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1/*
2 * Routines having to do with the 'struct sk_buff' memory handlers.
3 *
4 * Authors: Alan Cox <alan@lxorguk.ukuu.org.uk>
5 * Florian La Roche <rzsfl@rz.uni-sb.de>
6 *
7 * Fixes:
8 * Alan Cox : Fixed the worst of the load
9 * balancer bugs.
10 * Dave Platt : Interrupt stacking fix.
11 * Richard Kooijman : Timestamp fixes.
12 * Alan Cox : Changed buffer format.
13 * Alan Cox : destructor hook for AF_UNIX etc.
14 * Linus Torvalds : Better skb_clone.
15 * Alan Cox : Added skb_copy.
16 * Alan Cox : Added all the changed routines Linus
17 * only put in the headers
18 * Ray VanTassle : Fixed --skb->lock in free
19 * Alan Cox : skb_copy copy arp field
20 * Andi Kleen : slabified it.
21 * Robert Olsson : Removed skb_head_pool
22 *
23 * NOTE:
24 * The __skb_ routines should be called with interrupts
25 * disabled, or you better be *real* sure that the operation is atomic
26 * with respect to whatever list is being frobbed (e.g. via lock_sock()
27 * or via disabling bottom half handlers, etc).
28 *
29 * This program is free software; you can redistribute it and/or
30 * modify it under the terms of the GNU General Public License
31 * as published by the Free Software Foundation; either version
32 * 2 of the License, or (at your option) any later version.
33 */
34
35/*
36 * The functions in this file will not compile correctly with gcc 2.4.x
37 */
38
39#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
40
41#include <linux/module.h>
42#include <linux/types.h>
43#include <linux/kernel.h>
44#include <linux/kmemcheck.h>
45#include <linux/mm.h>
46#include <linux/interrupt.h>
47#include <linux/in.h>
48#include <linux/inet.h>
49#include <linux/slab.h>
50#include <linux/tcp.h>
51#include <linux/udp.h>
52#include <linux/netdevice.h>
53#ifdef CONFIG_NET_CLS_ACT
54#include <net/pkt_sched.h>
55#endif
56#include <linux/string.h>
57#include <linux/skbuff.h>
58#include <linux/splice.h>
59#include <linux/cache.h>
60#include <linux/rtnetlink.h>
61#include <linux/init.h>
62#include <linux/scatterlist.h>
63#include <linux/errqueue.h>
64#include <linux/prefetch.h>
65#include <linux/if_vlan.h>
66
67#include <net/protocol.h>
68#include <net/dst.h>
69#include <net/sock.h>
70#include <net/checksum.h>
71#include <net/ip6_checksum.h>
72#include <net/xfrm.h>
73
74#include <asm/uaccess.h>
75#include <trace/events/skb.h>
76#include <linux/highmem.h>
77#include <linux/capability.h>
78#include <linux/user_namespace.h>
79
80struct kmem_cache *skbuff_head_cache __read_mostly;
81static struct kmem_cache *skbuff_fclone_cache __read_mostly;
82int sysctl_max_skb_frags __read_mostly = MAX_SKB_FRAGS;
83EXPORT_SYMBOL(sysctl_max_skb_frags);
84
85/**
86 * skb_panic - private function for out-of-line support
87 * @skb: buffer
88 * @sz: size
89 * @addr: address
90 * @msg: skb_over_panic or skb_under_panic
91 *
92 * Out-of-line support for skb_put() and skb_push().
93 * Called via the wrapper skb_over_panic() or skb_under_panic().
94 * Keep out of line to prevent kernel bloat.
95 * __builtin_return_address is not used because it is not always reliable.
96 */
97static void skb_panic(struct sk_buff *skb, unsigned int sz, void *addr,
98 const char msg[])
99{
100 pr_emerg("%s: text:%p len:%d put:%d head:%p data:%p tail:%#lx end:%#lx dev:%s\n",
101 msg, addr, skb->len, sz, skb->head, skb->data,
102 (unsigned long)skb->tail, (unsigned long)skb->end,
103 skb->dev ? skb->dev->name : "<NULL>");
104 BUG();
105}
106
107static void skb_over_panic(struct sk_buff *skb, unsigned int sz, void *addr)
108{
109 skb_panic(skb, sz, addr, __func__);
110}
111
112static void skb_under_panic(struct sk_buff *skb, unsigned int sz, void *addr)
113{
114 skb_panic(skb, sz, addr, __func__);
115}
116
117/*
118 * kmalloc_reserve is a wrapper around kmalloc_node_track_caller that tells
119 * the caller if emergency pfmemalloc reserves are being used. If it is and
120 * the socket is later found to be SOCK_MEMALLOC then PFMEMALLOC reserves
121 * may be used. Otherwise, the packet data may be discarded until enough
122 * memory is free
123 */
124#define kmalloc_reserve(size, gfp, node, pfmemalloc) \
125 __kmalloc_reserve(size, gfp, node, _RET_IP_, pfmemalloc)
126
127static void *__kmalloc_reserve(size_t size, gfp_t flags, int node,
128 unsigned long ip, bool *pfmemalloc)
129{
130 void *obj;
131 bool ret_pfmemalloc = false;
132
133 /*
134 * Try a regular allocation, when that fails and we're not entitled
135 * to the reserves, fail.
136 */
137 obj = kmalloc_node_track_caller(size,
138 flags | __GFP_NOMEMALLOC | __GFP_NOWARN,
139 node);
140 if (obj || !(gfp_pfmemalloc_allowed(flags)))
141 goto out;
142
143 /* Try again but now we are using pfmemalloc reserves */
144 ret_pfmemalloc = true;
145 obj = kmalloc_node_track_caller(size, flags, node);
146
147out:
148 if (pfmemalloc)
149 *pfmemalloc = ret_pfmemalloc;
150
151 return obj;
152}
153
154/* Allocate a new skbuff. We do this ourselves so we can fill in a few
155 * 'private' fields and also do memory statistics to find all the
156 * [BEEP] leaks.
157 *
158 */
159
160struct sk_buff *__alloc_skb_head(gfp_t gfp_mask, int node)
161{
162 struct sk_buff *skb;
163
164 /* Get the HEAD */
165 skb = kmem_cache_alloc_node(skbuff_head_cache,
166 gfp_mask & ~__GFP_DMA, node);
167 if (!skb)
168 goto out;
169
170 /*
171 * Only clear those fields we need to clear, not those that we will
172 * actually initialise below. Hence, don't put any more fields after
173 * the tail pointer in struct sk_buff!
174 */
175 memset(skb, 0, offsetof(struct sk_buff, tail));
176 skb->head = NULL;
177 skb->truesize = sizeof(struct sk_buff);
178 atomic_set(&skb->users, 1);
179
180 skb->mac_header = (typeof(skb->mac_header))~0U;
181out:
182 return skb;
183}
184
185/**
186 * __alloc_skb - allocate a network buffer
187 * @size: size to allocate
188 * @gfp_mask: allocation mask
189 * @flags: If SKB_ALLOC_FCLONE is set, allocate from fclone cache
190 * instead of head cache and allocate a cloned (child) skb.
191 * If SKB_ALLOC_RX is set, __GFP_MEMALLOC will be used for
192 * allocations in case the data is required for writeback
193 * @node: numa node to allocate memory on
194 *
195 * Allocate a new &sk_buff. The returned buffer has no headroom and a
196 * tail room of at least size bytes. The object has a reference count
197 * of one. The return is the buffer. On a failure the return is %NULL.
198 *
199 * Buffers may only be allocated from interrupts using a @gfp_mask of
200 * %GFP_ATOMIC.
201 */
202struct sk_buff *__alloc_skb(unsigned int size, gfp_t gfp_mask,
203 int flags, int node)
204{
205 struct kmem_cache *cache;
206 struct skb_shared_info *shinfo;
207 struct sk_buff *skb;
208 u8 *data;
209 bool pfmemalloc;
210
211 cache = (flags & SKB_ALLOC_FCLONE)
212 ? skbuff_fclone_cache : skbuff_head_cache;
213
214 if (sk_memalloc_socks() && (flags & SKB_ALLOC_RX))
215 gfp_mask |= __GFP_MEMALLOC;
216
217 /* Get the HEAD */
218 skb = kmem_cache_alloc_node(cache, gfp_mask & ~__GFP_DMA, node);
219 if (!skb)
220 goto out;
221 prefetchw(skb);
222
223 /* We do our best to align skb_shared_info on a separate cache
224 * line. It usually works because kmalloc(X > SMP_CACHE_BYTES) gives
225 * aligned memory blocks, unless SLUB/SLAB debug is enabled.
226 * Both skb->head and skb_shared_info are cache line aligned.
227 */
228 size = SKB_DATA_ALIGN(size);
229 size += SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
230 data = kmalloc_reserve(size, gfp_mask, node, &pfmemalloc);
231 if (!data)
232 goto nodata;
233 /* kmalloc(size) might give us more room than requested.
234 * Put skb_shared_info exactly at the end of allocated zone,
235 * to allow max possible filling before reallocation.
236 */
237 size = SKB_WITH_OVERHEAD(ksize(data));
238 prefetchw(data + size);
239
240 /*
241 * Only clear those fields we need to clear, not those that we will
242 * actually initialise below. Hence, don't put any more fields after
243 * the tail pointer in struct sk_buff!
244 */
245 memset(skb, 0, offsetof(struct sk_buff, tail));
246 /* Account for allocated memory : skb + skb->head */
247 skb->truesize = SKB_TRUESIZE(size);
248 skb->pfmemalloc = pfmemalloc;
249 atomic_set(&skb->users, 1);
250 skb->head = data;
251 skb->data = data;
252 skb_reset_tail_pointer(skb);
253 skb->end = skb->tail + size;
254 skb->mac_header = (typeof(skb->mac_header))~0U;
255 skb->transport_header = (typeof(skb->transport_header))~0U;
256
257 /* make sure we initialize shinfo sequentially */
258 shinfo = skb_shinfo(skb);
259 memset(shinfo, 0, offsetof(struct skb_shared_info, dataref));
260 atomic_set(&shinfo->dataref, 1);
261 kmemcheck_annotate_variable(shinfo->destructor_arg);
262
263 if (flags & SKB_ALLOC_FCLONE) {
264 struct sk_buff_fclones *fclones;
265
266 fclones = container_of(skb, struct sk_buff_fclones, skb1);
267
268 kmemcheck_annotate_bitfield(&fclones->skb2, flags1);
269 skb->fclone = SKB_FCLONE_ORIG;
270 atomic_set(&fclones->fclone_ref, 1);
271
272 fclones->skb2.fclone = SKB_FCLONE_CLONE;
273 fclones->skb2.pfmemalloc = pfmemalloc;
274 }
275out:
276 return skb;
277nodata:
278 kmem_cache_free(cache, skb);
279 skb = NULL;
280 goto out;
281}
282EXPORT_SYMBOL(__alloc_skb);
283
284/**
285 * __build_skb - build a network buffer
286 * @data: data buffer provided by caller
287 * @frag_size: size of data, or 0 if head was kmalloced
288 *
289 * Allocate a new &sk_buff. Caller provides space holding head and
290 * skb_shared_info. @data must have been allocated by kmalloc() only if
291 * @frag_size is 0, otherwise data should come from the page allocator
292 * or vmalloc()
293 * The return is the new skb buffer.
294 * On a failure the return is %NULL, and @data is not freed.
295 * Notes :
296 * Before IO, driver allocates only data buffer where NIC put incoming frame
297 * Driver should add room at head (NET_SKB_PAD) and
298 * MUST add room at tail (SKB_DATA_ALIGN(skb_shared_info))
299 * After IO, driver calls build_skb(), to allocate sk_buff and populate it
300 * before giving packet to stack.
301 * RX rings only contains data buffers, not full skbs.
302 */
303struct sk_buff *__build_skb(void *data, unsigned int frag_size)
304{
305 struct skb_shared_info *shinfo;
306 struct sk_buff *skb;
307 unsigned int size = frag_size ? : ksize(data);
308
309 skb = kmem_cache_alloc(skbuff_head_cache, GFP_ATOMIC);
310 if (!skb)
311 return NULL;
312
313 size -= SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
314
315 memset(skb, 0, offsetof(struct sk_buff, tail));
316 skb->truesize = SKB_TRUESIZE(size);
317 atomic_set(&skb->users, 1);
318 skb->head = data;
319 skb->data = data;
320 skb_reset_tail_pointer(skb);
321 skb->end = skb->tail + size;
322 skb->mac_header = (typeof(skb->mac_header))~0U;
323 skb->transport_header = (typeof(skb->transport_header))~0U;
324
325 /* make sure we initialize shinfo sequentially */
326 shinfo = skb_shinfo(skb);
327 memset(shinfo, 0, offsetof(struct skb_shared_info, dataref));
328 atomic_set(&shinfo->dataref, 1);
329 kmemcheck_annotate_variable(shinfo->destructor_arg);
330
331 return skb;
332}
333
334/* build_skb() is wrapper over __build_skb(), that specifically
335 * takes care of skb->head and skb->pfmemalloc
336 * This means that if @frag_size is not zero, then @data must be backed
337 * by a page fragment, not kmalloc() or vmalloc()
338 */
339struct sk_buff *build_skb(void *data, unsigned int frag_size)
340{
341 struct sk_buff *skb = __build_skb(data, frag_size);
342
343 if (skb && frag_size) {
344 skb->head_frag = 1;
345 if (page_is_pfmemalloc(virt_to_head_page(data)))
346 skb->pfmemalloc = 1;
347 }
348 return skb;
349}
350EXPORT_SYMBOL(build_skb);
351
352#define NAPI_SKB_CACHE_SIZE 64
353
354struct napi_alloc_cache {
355 struct page_frag_cache page;
356 size_t skb_count;
357 void *skb_cache[NAPI_SKB_CACHE_SIZE];
358};
359
360static DEFINE_PER_CPU(struct page_frag_cache, netdev_alloc_cache);
361static DEFINE_PER_CPU(struct napi_alloc_cache, napi_alloc_cache);
362
363static void *__netdev_alloc_frag(unsigned int fragsz, gfp_t gfp_mask)
364{
365 struct page_frag_cache *nc;
366 unsigned long flags;
367 void *data;
368
369 local_irq_save(flags);
370 nc = this_cpu_ptr(&netdev_alloc_cache);
371 data = __alloc_page_frag(nc, fragsz, gfp_mask);
372 local_irq_restore(flags);
373 return data;
374}
375
376/**
377 * netdev_alloc_frag - allocate a page fragment
378 * @fragsz: fragment size
379 *
380 * Allocates a frag from a page for receive buffer.
381 * Uses GFP_ATOMIC allocations.
382 */
383void *netdev_alloc_frag(unsigned int fragsz)
384{
385 return __netdev_alloc_frag(fragsz, GFP_ATOMIC | __GFP_COLD);
386}
387EXPORT_SYMBOL(netdev_alloc_frag);
388
389static void *__napi_alloc_frag(unsigned int fragsz, gfp_t gfp_mask)
390{
391 struct napi_alloc_cache *nc = this_cpu_ptr(&napi_alloc_cache);
392
393 return __alloc_page_frag(&nc->page, fragsz, gfp_mask);
394}
395
396void *napi_alloc_frag(unsigned int fragsz)
397{
398 return __napi_alloc_frag(fragsz, GFP_ATOMIC | __GFP_COLD);
399}
400EXPORT_SYMBOL(napi_alloc_frag);
401
402/**
403 * __netdev_alloc_skb - allocate an skbuff for rx on a specific device
404 * @dev: network device to receive on
405 * @len: length to allocate
406 * @gfp_mask: get_free_pages mask, passed to alloc_skb
407 *
408 * Allocate a new &sk_buff and assign it a usage count of one. The
409 * buffer has NET_SKB_PAD headroom built in. Users should allocate
410 * the headroom they think they need without accounting for the
411 * built in space. The built in space is used for optimisations.
412 *
413 * %NULL is returned if there is no free memory.
414 */
415struct sk_buff *__netdev_alloc_skb(struct net_device *dev, unsigned int len,
416 gfp_t gfp_mask)
417{
418 struct page_frag_cache *nc;
419 unsigned long flags;
420 struct sk_buff *skb;
421 bool pfmemalloc;
422 void *data;
423
424 len += NET_SKB_PAD;
425
426 if ((len > SKB_WITH_OVERHEAD(PAGE_SIZE)) ||
427 (gfp_mask & (__GFP_DIRECT_RECLAIM | GFP_DMA))) {
428 skb = __alloc_skb(len, gfp_mask, SKB_ALLOC_RX, NUMA_NO_NODE);
429 if (!skb)
430 goto skb_fail;
431 goto skb_success;
432 }
433
434 len += SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
435 len = SKB_DATA_ALIGN(len);
436
437 if (sk_memalloc_socks())
438 gfp_mask |= __GFP_MEMALLOC;
439
440 local_irq_save(flags);
441
442 nc = this_cpu_ptr(&netdev_alloc_cache);
443 data = __alloc_page_frag(nc, len, gfp_mask);
444 pfmemalloc = nc->pfmemalloc;
445
446 local_irq_restore(flags);
447
448 if (unlikely(!data))
449 return NULL;
450
451 skb = __build_skb(data, len);
452 if (unlikely(!skb)) {
453 skb_free_frag(data);
454 return NULL;
455 }
456
457 /* use OR instead of assignment to avoid clearing of bits in mask */
458 if (pfmemalloc)
459 skb->pfmemalloc = 1;
460 skb->head_frag = 1;
461
462skb_success:
463 skb_reserve(skb, NET_SKB_PAD);
464 skb->dev = dev;
465
466skb_fail:
467 return skb;
468}
469EXPORT_SYMBOL(__netdev_alloc_skb);
470
471/**
472 * __napi_alloc_skb - allocate skbuff for rx in a specific NAPI instance
473 * @napi: napi instance this buffer was allocated for
474 * @len: length to allocate
475 * @gfp_mask: get_free_pages mask, passed to alloc_skb and alloc_pages
476 *
477 * Allocate a new sk_buff for use in NAPI receive. This buffer will
478 * attempt to allocate the head from a special reserved region used
479 * only for NAPI Rx allocation. By doing this we can save several
480 * CPU cycles by avoiding having to disable and re-enable IRQs.
481 *
482 * %NULL is returned if there is no free memory.
483 */
484struct sk_buff *__napi_alloc_skb(struct napi_struct *napi, unsigned int len,
485 gfp_t gfp_mask)
486{
487 struct napi_alloc_cache *nc = this_cpu_ptr(&napi_alloc_cache);
488 struct sk_buff *skb;
489 void *data;
490
491 len += NET_SKB_PAD + NET_IP_ALIGN;
492
493 if ((len > SKB_WITH_OVERHEAD(PAGE_SIZE)) ||
494 (gfp_mask & (__GFP_DIRECT_RECLAIM | GFP_DMA))) {
495 skb = __alloc_skb(len, gfp_mask, SKB_ALLOC_RX, NUMA_NO_NODE);
496 if (!skb)
497 goto skb_fail;
498 goto skb_success;
499 }
500
501 len += SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
502 len = SKB_DATA_ALIGN(len);
503
504 if (sk_memalloc_socks())
505 gfp_mask |= __GFP_MEMALLOC;
506
507 data = __alloc_page_frag(&nc->page, len, gfp_mask);
508 if (unlikely(!data))
509 return NULL;
510
511 skb = __build_skb(data, len);
512 if (unlikely(!skb)) {
513 skb_free_frag(data);
514 return NULL;
515 }
516
517 /* use OR instead of assignment to avoid clearing of bits in mask */
518 if (nc->page.pfmemalloc)
519 skb->pfmemalloc = 1;
520 skb->head_frag = 1;
521
522skb_success:
523 skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN);
524 skb->dev = napi->dev;
525
526skb_fail:
527 return skb;
528}
529EXPORT_SYMBOL(__napi_alloc_skb);
530
531void skb_add_rx_frag(struct sk_buff *skb, int i, struct page *page, int off,
532 int size, unsigned int truesize)
533{
534 skb_fill_page_desc(skb, i, page, off, size);
535 skb->len += size;
536 skb->data_len += size;
537 skb->truesize += truesize;
538}
539EXPORT_SYMBOL(skb_add_rx_frag);
540
541void skb_coalesce_rx_frag(struct sk_buff *skb, int i, int size,
542 unsigned int truesize)
543{
544 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
545
546 skb_frag_size_add(frag, size);
547 skb->len += size;
548 skb->data_len += size;
549 skb->truesize += truesize;
550}
551EXPORT_SYMBOL(skb_coalesce_rx_frag);
552
553static void skb_drop_list(struct sk_buff **listp)
554{
555 kfree_skb_list(*listp);
556 *listp = NULL;
557}
558
559static inline void skb_drop_fraglist(struct sk_buff *skb)
560{
561 skb_drop_list(&skb_shinfo(skb)->frag_list);
562}
563
564static void skb_clone_fraglist(struct sk_buff *skb)
565{
566 struct sk_buff *list;
567
568 skb_walk_frags(skb, list)
569 skb_get(list);
570}
571
572static void skb_free_head(struct sk_buff *skb)
573{
574 unsigned char *head = skb->head;
575
576 if (skb->head_frag)
577 skb_free_frag(head);
578 else
579 kfree(head);
580}
581
582static void skb_release_data(struct sk_buff *skb)
583{
584 struct skb_shared_info *shinfo = skb_shinfo(skb);
585 int i;
586
587 if (skb->cloned &&
588 atomic_sub_return(skb->nohdr ? (1 << SKB_DATAREF_SHIFT) + 1 : 1,
589 &shinfo->dataref))
590 return;
591
592 for (i = 0; i < shinfo->nr_frags; i++)
593 __skb_frag_unref(&shinfo->frags[i]);
594
595 /*
596 * If skb buf is from userspace, we need to notify the caller
597 * the lower device DMA has done;
598 */
599 if (shinfo->tx_flags & SKBTX_DEV_ZEROCOPY) {
600 struct ubuf_info *uarg;
601
602 uarg = shinfo->destructor_arg;
603 if (uarg->callback)
604 uarg->callback(uarg, true);
605 }
606
607 if (shinfo->frag_list)
608 kfree_skb_list(shinfo->frag_list);
609
610 skb_free_head(skb);
611}
612
613/*
614 * Free an skbuff by memory without cleaning the state.
615 */
616static void kfree_skbmem(struct sk_buff *skb)
617{
618 struct sk_buff_fclones *fclones;
619
620 switch (skb->fclone) {
621 case SKB_FCLONE_UNAVAILABLE:
622 kmem_cache_free(skbuff_head_cache, skb);
623 return;
624
625 case SKB_FCLONE_ORIG:
626 fclones = container_of(skb, struct sk_buff_fclones, skb1);
627
628 /* We usually free the clone (TX completion) before original skb
629 * This test would have no chance to be true for the clone,
630 * while here, branch prediction will be good.
631 */
632 if (atomic_read(&fclones->fclone_ref) == 1)
633 goto fastpath;
634 break;
635
636 default: /* SKB_FCLONE_CLONE */
637 fclones = container_of(skb, struct sk_buff_fclones, skb2);
638 break;
639 }
640 if (!atomic_dec_and_test(&fclones->fclone_ref))
641 return;
642fastpath:
643 kmem_cache_free(skbuff_fclone_cache, fclones);
644}
645
646static void skb_release_head_state(struct sk_buff *skb)
647{
648 skb_dst_drop(skb);
649#ifdef CONFIG_XFRM
650 secpath_put(skb->sp);
651#endif
652 if (skb->destructor) {
653 WARN_ON(in_irq());
654 skb->destructor(skb);
655 }
656#if IS_ENABLED(CONFIG_NF_CONNTRACK)
657 nf_conntrack_put(skb->nfct);
658#endif
659#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
660 nf_bridge_put(skb->nf_bridge);
661#endif
662}
663
664/* Free everything but the sk_buff shell. */
665static void skb_release_all(struct sk_buff *skb)
666{
667 skb_release_head_state(skb);
668 if (likely(skb->head))
669 skb_release_data(skb);
670}
671
672/**
673 * __kfree_skb - private function
674 * @skb: buffer
675 *
676 * Free an sk_buff. Release anything attached to the buffer.
677 * Clean the state. This is an internal helper function. Users should
678 * always call kfree_skb
679 */
680
681void __kfree_skb(struct sk_buff *skb)
682{
683 skb_release_all(skb);
684 kfree_skbmem(skb);
685}
686EXPORT_SYMBOL(__kfree_skb);
687
688/**
689 * kfree_skb - free an sk_buff
690 * @skb: buffer to free
691 *
692 * Drop a reference to the buffer and free it if the usage count has
693 * hit zero.
694 */
695void kfree_skb(struct sk_buff *skb)
696{
697 if (unlikely(!skb))
698 return;
699 if (likely(atomic_read(&skb->users) == 1))
700 smp_rmb();
701 else if (likely(!atomic_dec_and_test(&skb->users)))
702 return;
703 trace_kfree_skb(skb, __builtin_return_address(0));
704 __kfree_skb(skb);
705}
706EXPORT_SYMBOL(kfree_skb);
707
708void kfree_skb_list(struct sk_buff *segs)
709{
710 while (segs) {
711 struct sk_buff *next = segs->next;
712
713 kfree_skb(segs);
714 segs = next;
715 }
716}
717EXPORT_SYMBOL(kfree_skb_list);
718
719/**
720 * skb_tx_error - report an sk_buff xmit error
721 * @skb: buffer that triggered an error
722 *
723 * Report xmit error if a device callback is tracking this skb.
724 * skb must be freed afterwards.
725 */
726void skb_tx_error(struct sk_buff *skb)
727{
728 if (skb_shinfo(skb)->tx_flags & SKBTX_DEV_ZEROCOPY) {
729 struct ubuf_info *uarg;
730
731 uarg = skb_shinfo(skb)->destructor_arg;
732 if (uarg->callback)
733 uarg->callback(uarg, false);
734 skb_shinfo(skb)->tx_flags &= ~SKBTX_DEV_ZEROCOPY;
735 }
736}
737EXPORT_SYMBOL(skb_tx_error);
738
739/**
740 * consume_skb - free an skbuff
741 * @skb: buffer to free
742 *
743 * Drop a ref to the buffer and free it if the usage count has hit zero
744 * Functions identically to kfree_skb, but kfree_skb assumes that the frame
745 * is being dropped after a failure and notes that
746 */
747void consume_skb(struct sk_buff *skb)
748{
749 if (unlikely(!skb))
750 return;
751 if (likely(atomic_read(&skb->users) == 1))
752 smp_rmb();
753 else if (likely(!atomic_dec_and_test(&skb->users)))
754 return;
755 trace_consume_skb(skb);
756 __kfree_skb(skb);
757}
758EXPORT_SYMBOL(consume_skb);
759
760void __kfree_skb_flush(void)
761{
762 struct napi_alloc_cache *nc = this_cpu_ptr(&napi_alloc_cache);
763
764 /* flush skb_cache if containing objects */
765 if (nc->skb_count) {
766 kmem_cache_free_bulk(skbuff_head_cache, nc->skb_count,
767 nc->skb_cache);
768 nc->skb_count = 0;
769 }
770}
771
772static inline void _kfree_skb_defer(struct sk_buff *skb)
773{
774 struct napi_alloc_cache *nc = this_cpu_ptr(&napi_alloc_cache);
775
776 /* drop skb->head and call any destructors for packet */
777 skb_release_all(skb);
778
779 /* record skb to CPU local list */
780 nc->skb_cache[nc->skb_count++] = skb;
781
782#ifdef CONFIG_SLUB
783 /* SLUB writes into objects when freeing */
784 prefetchw(skb);
785#endif
786
787 /* flush skb_cache if it is filled */
788 if (unlikely(nc->skb_count == NAPI_SKB_CACHE_SIZE)) {
789 kmem_cache_free_bulk(skbuff_head_cache, NAPI_SKB_CACHE_SIZE,
790 nc->skb_cache);
791 nc->skb_count = 0;
792 }
793}
794void __kfree_skb_defer(struct sk_buff *skb)
795{
796 _kfree_skb_defer(skb);
797}
798
799void napi_consume_skb(struct sk_buff *skb, int budget)
800{
801 if (unlikely(!skb))
802 return;
803
804 /* Zero budget indicate non-NAPI context called us, like netpoll */
805 if (unlikely(!budget)) {
806 dev_consume_skb_any(skb);
807 return;
808 }
809
810 if (likely(atomic_read(&skb->users) == 1))
811 smp_rmb();
812 else if (likely(!atomic_dec_and_test(&skb->users)))
813 return;
814 /* if reaching here SKB is ready to free */
815 trace_consume_skb(skb);
816
817 /* if SKB is a clone, don't handle this case */
818 if (skb->fclone != SKB_FCLONE_UNAVAILABLE) {
819 __kfree_skb(skb);
820 return;
821 }
822
823 _kfree_skb_defer(skb);
824}
825EXPORT_SYMBOL(napi_consume_skb);
826
827/* Make sure a field is enclosed inside headers_start/headers_end section */
828#define CHECK_SKB_FIELD(field) \
829 BUILD_BUG_ON(offsetof(struct sk_buff, field) < \
830 offsetof(struct sk_buff, headers_start)); \
831 BUILD_BUG_ON(offsetof(struct sk_buff, field) > \
832 offsetof(struct sk_buff, headers_end)); \
833
834static void __copy_skb_header(struct sk_buff *new, const struct sk_buff *old)
835{
836 new->tstamp = old->tstamp;
837 /* We do not copy old->sk */
838 new->dev = old->dev;
839 memcpy(new->cb, old->cb, sizeof(old->cb));
840 skb_dst_copy(new, old);
841#ifdef CONFIG_XFRM
842 new->sp = secpath_get(old->sp);
843#endif
844 __nf_copy(new, old, false);
845
846 /* Note : this field could be in headers_start/headers_end section
847 * It is not yet because we do not want to have a 16 bit hole
848 */
849 new->queue_mapping = old->queue_mapping;
850
851 memcpy(&new->headers_start, &old->headers_start,
852 offsetof(struct sk_buff, headers_end) -
853 offsetof(struct sk_buff, headers_start));
854 CHECK_SKB_FIELD(protocol);
855 CHECK_SKB_FIELD(csum);
856 CHECK_SKB_FIELD(hash);
857 CHECK_SKB_FIELD(priority);
858 CHECK_SKB_FIELD(skb_iif);
859 CHECK_SKB_FIELD(vlan_proto);
860 CHECK_SKB_FIELD(vlan_tci);
861 CHECK_SKB_FIELD(transport_header);
862 CHECK_SKB_FIELD(network_header);
863 CHECK_SKB_FIELD(mac_header);
864 CHECK_SKB_FIELD(inner_protocol);
865 CHECK_SKB_FIELD(inner_transport_header);
866 CHECK_SKB_FIELD(inner_network_header);
867 CHECK_SKB_FIELD(inner_mac_header);
868 CHECK_SKB_FIELD(mark);
869#ifdef CONFIG_NETWORK_SECMARK
870 CHECK_SKB_FIELD(secmark);
871#endif
872#ifdef CONFIG_NET_RX_BUSY_POLL
873 CHECK_SKB_FIELD(napi_id);
874#endif
875#ifdef CONFIG_XPS
876 CHECK_SKB_FIELD(sender_cpu);
877#endif
878#ifdef CONFIG_NET_SCHED
879 CHECK_SKB_FIELD(tc_index);
880#ifdef CONFIG_NET_CLS_ACT
881 CHECK_SKB_FIELD(tc_verd);
882#endif
883#endif
884
885}
886
887/*
888 * You should not add any new code to this function. Add it to
889 * __copy_skb_header above instead.
890 */
891static struct sk_buff *__skb_clone(struct sk_buff *n, struct sk_buff *skb)
892{
893#define C(x) n->x = skb->x
894
895 n->next = n->prev = NULL;
896 n->sk = NULL;
897 __copy_skb_header(n, skb);
898
899 C(len);
900 C(data_len);
901 C(mac_len);
902 n->hdr_len = skb->nohdr ? skb_headroom(skb) : skb->hdr_len;
903 n->cloned = 1;
904 n->nohdr = 0;
905 n->destructor = NULL;
906 C(tail);
907 C(end);
908 C(head);
909 C(head_frag);
910 C(data);
911 C(truesize);
912 atomic_set(&n->users, 1);
913
914 atomic_inc(&(skb_shinfo(skb)->dataref));
915 skb->cloned = 1;
916
917 return n;
918#undef C
919}
920
921/**
922 * skb_morph - morph one skb into another
923 * @dst: the skb to receive the contents
924 * @src: the skb to supply the contents
925 *
926 * This is identical to skb_clone except that the target skb is
927 * supplied by the user.
928 *
929 * The target skb is returned upon exit.
930 */
931struct sk_buff *skb_morph(struct sk_buff *dst, struct sk_buff *src)
932{
933 skb_release_all(dst);
934 return __skb_clone(dst, src);
935}
936EXPORT_SYMBOL_GPL(skb_morph);
937
938/**
939 * skb_copy_ubufs - copy userspace skb frags buffers to kernel
940 * @skb: the skb to modify
941 * @gfp_mask: allocation priority
942 *
943 * This must be called on SKBTX_DEV_ZEROCOPY skb.
944 * It will copy all frags into kernel and drop the reference
945 * to userspace pages.
946 *
947 * If this function is called from an interrupt gfp_mask() must be
948 * %GFP_ATOMIC.
949 *
950 * Returns 0 on success or a negative error code on failure
951 * to allocate kernel memory to copy to.
952 */
953int skb_copy_ubufs(struct sk_buff *skb, gfp_t gfp_mask)
954{
955 int i;
956 int num_frags = skb_shinfo(skb)->nr_frags;
957 struct page *page, *head = NULL;
958 struct ubuf_info *uarg = skb_shinfo(skb)->destructor_arg;
959
960 for (i = 0; i < num_frags; i++) {
961 u8 *vaddr;
962 skb_frag_t *f = &skb_shinfo(skb)->frags[i];
963
964 page = alloc_page(gfp_mask);
965 if (!page) {
966 while (head) {
967 struct page *next = (struct page *)page_private(head);
968 put_page(head);
969 head = next;
970 }
971 return -ENOMEM;
972 }
973 vaddr = kmap_atomic(skb_frag_page(f));
974 memcpy(page_address(page),
975 vaddr + f->page_offset, skb_frag_size(f));
976 kunmap_atomic(vaddr);
977 set_page_private(page, (unsigned long)head);
978 head = page;
979 }
980
981 /* skb frags release userspace buffers */
982 for (i = 0; i < num_frags; i++)
983 skb_frag_unref(skb, i);
984
985 uarg->callback(uarg, false);
986
987 /* skb frags point to kernel buffers */
988 for (i = num_frags - 1; i >= 0; i--) {
989 __skb_fill_page_desc(skb, i, head, 0,
990 skb_shinfo(skb)->frags[i].size);
991 head = (struct page *)page_private(head);
992 }
993
994 skb_shinfo(skb)->tx_flags &= ~SKBTX_DEV_ZEROCOPY;
995 return 0;
996}
997EXPORT_SYMBOL_GPL(skb_copy_ubufs);
998
999/**
1000 * skb_clone - duplicate an sk_buff
1001 * @skb: buffer to clone
1002 * @gfp_mask: allocation priority
1003 *
1004 * Duplicate an &sk_buff. The new one is not owned by a socket. Both
1005 * copies share the same packet data but not structure. The new
1006 * buffer has a reference count of 1. If the allocation fails the
1007 * function returns %NULL otherwise the new buffer is returned.
1008 *
1009 * If this function is called from an interrupt gfp_mask() must be
1010 * %GFP_ATOMIC.
1011 */
1012
1013struct sk_buff *skb_clone(struct sk_buff *skb, gfp_t gfp_mask)
1014{
1015 struct sk_buff_fclones *fclones = container_of(skb,
1016 struct sk_buff_fclones,
1017 skb1);
1018 struct sk_buff *n;
1019
1020 if (skb_orphan_frags(skb, gfp_mask))
1021 return NULL;
1022
1023 if (skb->fclone == SKB_FCLONE_ORIG &&
1024 atomic_read(&fclones->fclone_ref) == 1) {
1025 n = &fclones->skb2;
1026 atomic_set(&fclones->fclone_ref, 2);
1027 } else {
1028 if (skb_pfmemalloc(skb))
1029 gfp_mask |= __GFP_MEMALLOC;
1030
1031 n = kmem_cache_alloc(skbuff_head_cache, gfp_mask);
1032 if (!n)
1033 return NULL;
1034
1035 kmemcheck_annotate_bitfield(n, flags1);
1036 n->fclone = SKB_FCLONE_UNAVAILABLE;
1037 }
1038
1039 return __skb_clone(n, skb);
1040}
1041EXPORT_SYMBOL(skb_clone);
1042
1043static void skb_headers_offset_update(struct sk_buff *skb, int off)
1044{
1045 /* Only adjust this if it actually is csum_start rather than csum */
1046 if (skb->ip_summed == CHECKSUM_PARTIAL)
1047 skb->csum_start += off;
1048 /* {transport,network,mac}_header and tail are relative to skb->head */
1049 skb->transport_header += off;
1050 skb->network_header += off;
1051 if (skb_mac_header_was_set(skb))
1052 skb->mac_header += off;
1053 skb->inner_transport_header += off;
1054 skb->inner_network_header += off;
1055 skb->inner_mac_header += off;
1056}
1057
1058static void copy_skb_header(struct sk_buff *new, const struct sk_buff *old)
1059{
1060 __copy_skb_header(new, old);
1061
1062 skb_shinfo(new)->gso_size = skb_shinfo(old)->gso_size;
1063 skb_shinfo(new)->gso_segs = skb_shinfo(old)->gso_segs;
1064 skb_shinfo(new)->gso_type = skb_shinfo(old)->gso_type;
1065}
1066
1067static inline int skb_alloc_rx_flag(const struct sk_buff *skb)
1068{
1069 if (skb_pfmemalloc(skb))
1070 return SKB_ALLOC_RX;
1071 return 0;
1072}
1073
1074/**
1075 * skb_copy - create private copy of an sk_buff
1076 * @skb: buffer to copy
1077 * @gfp_mask: allocation priority
1078 *
1079 * Make a copy of both an &sk_buff and its data. This is used when the
1080 * caller wishes to modify the data and needs a private copy of the
1081 * data to alter. Returns %NULL on failure or the pointer to the buffer
1082 * on success. The returned buffer has a reference count of 1.
1083 *
1084 * As by-product this function converts non-linear &sk_buff to linear
1085 * one, so that &sk_buff becomes completely private and caller is allowed
1086 * to modify all the data of returned buffer. This means that this
1087 * function is not recommended for use in circumstances when only
1088 * header is going to be modified. Use pskb_copy() instead.
1089 */
1090
1091struct sk_buff *skb_copy(const struct sk_buff *skb, gfp_t gfp_mask)
1092{
1093 int headerlen = skb_headroom(skb);
1094 unsigned int size = skb_end_offset(skb) + skb->data_len;
1095 struct sk_buff *n = __alloc_skb(size, gfp_mask,
1096 skb_alloc_rx_flag(skb), NUMA_NO_NODE);
1097
1098 if (!n)
1099 return NULL;
1100
1101 /* Set the data pointer */
1102 skb_reserve(n, headerlen);
1103 /* Set the tail pointer and length */
1104 skb_put(n, skb->len);
1105
1106 if (skb_copy_bits(skb, -headerlen, n->head, headerlen + skb->len))
1107 BUG();
1108
1109 copy_skb_header(n, skb);
1110 return n;
1111}
1112EXPORT_SYMBOL(skb_copy);
1113
1114/**
1115 * __pskb_copy_fclone - create copy of an sk_buff with private head.
1116 * @skb: buffer to copy
1117 * @headroom: headroom of new skb
1118 * @gfp_mask: allocation priority
1119 * @fclone: if true allocate the copy of the skb from the fclone
1120 * cache instead of the head cache; it is recommended to set this
1121 * to true for the cases where the copy will likely be cloned
1122 *
1123 * Make a copy of both an &sk_buff and part of its data, located
1124 * in header. Fragmented data remain shared. This is used when
1125 * the caller wishes to modify only header of &sk_buff and needs
1126 * private copy of the header to alter. Returns %NULL on failure
1127 * or the pointer to the buffer on success.
1128 * The returned buffer has a reference count of 1.
1129 */
1130
1131struct sk_buff *__pskb_copy_fclone(struct sk_buff *skb, int headroom,
1132 gfp_t gfp_mask, bool fclone)
1133{
1134 unsigned int size = skb_headlen(skb) + headroom;
1135 int flags = skb_alloc_rx_flag(skb) | (fclone ? SKB_ALLOC_FCLONE : 0);
1136 struct sk_buff *n = __alloc_skb(size, gfp_mask, flags, NUMA_NO_NODE);
1137
1138 if (!n)
1139 goto out;
1140
1141 /* Set the data pointer */
1142 skb_reserve(n, headroom);
1143 /* Set the tail pointer and length */
1144 skb_put(n, skb_headlen(skb));
1145 /* Copy the bytes */
1146 skb_copy_from_linear_data(skb, n->data, n->len);
1147
1148 n->truesize += skb->data_len;
1149 n->data_len = skb->data_len;
1150 n->len = skb->len;
1151
1152 if (skb_shinfo(skb)->nr_frags) {
1153 int i;
1154
1155 if (skb_orphan_frags(skb, gfp_mask)) {
1156 kfree_skb(n);
1157 n = NULL;
1158 goto out;
1159 }
1160 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
1161 skb_shinfo(n)->frags[i] = skb_shinfo(skb)->frags[i];
1162 skb_frag_ref(skb, i);
1163 }
1164 skb_shinfo(n)->nr_frags = i;
1165 }
1166
1167 if (skb_has_frag_list(skb)) {
1168 skb_shinfo(n)->frag_list = skb_shinfo(skb)->frag_list;
1169 skb_clone_fraglist(n);
1170 }
1171
1172 copy_skb_header(n, skb);
1173out:
1174 return n;
1175}
1176EXPORT_SYMBOL(__pskb_copy_fclone);
1177
1178/**
1179 * pskb_expand_head - reallocate header of &sk_buff
1180 * @skb: buffer to reallocate
1181 * @nhead: room to add at head
1182 * @ntail: room to add at tail
1183 * @gfp_mask: allocation priority
1184 *
1185 * Expands (or creates identical copy, if @nhead and @ntail are zero)
1186 * header of @skb. &sk_buff itself is not changed. &sk_buff MUST have
1187 * reference count of 1. Returns zero in the case of success or error,
1188 * if expansion failed. In the last case, &sk_buff is not changed.
1189 *
1190 * All the pointers pointing into skb header may change and must be
1191 * reloaded after call to this function.
1192 */
1193
1194int pskb_expand_head(struct sk_buff *skb, int nhead, int ntail,
1195 gfp_t gfp_mask)
1196{
1197 int i;
1198 u8 *data;
1199 int size = nhead + skb_end_offset(skb) + ntail;
1200 long off;
1201
1202 BUG_ON(nhead < 0);
1203
1204 if (skb_shared(skb))
1205 BUG();
1206
1207 size = SKB_DATA_ALIGN(size);
1208
1209 if (skb_pfmemalloc(skb))
1210 gfp_mask |= __GFP_MEMALLOC;
1211 data = kmalloc_reserve(size + SKB_DATA_ALIGN(sizeof(struct skb_shared_info)),
1212 gfp_mask, NUMA_NO_NODE, NULL);
1213 if (!data)
1214 goto nodata;
1215 size = SKB_WITH_OVERHEAD(ksize(data));
1216
1217 /* Copy only real data... and, alas, header. This should be
1218 * optimized for the cases when header is void.
1219 */
1220 memcpy(data + nhead, skb->head, skb_tail_pointer(skb) - skb->head);
1221
1222 memcpy((struct skb_shared_info *)(data + size),
1223 skb_shinfo(skb),
1224 offsetof(struct skb_shared_info, frags[skb_shinfo(skb)->nr_frags]));
1225
1226 /*
1227 * if shinfo is shared we must drop the old head gracefully, but if it
1228 * is not we can just drop the old head and let the existing refcount
1229 * be since all we did is relocate the values
1230 */
1231 if (skb_cloned(skb)) {
1232 /* copy this zero copy skb frags */
1233 if (skb_orphan_frags(skb, gfp_mask))
1234 goto nofrags;
1235 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
1236 skb_frag_ref(skb, i);
1237
1238 if (skb_has_frag_list(skb))
1239 skb_clone_fraglist(skb);
1240
1241 skb_release_data(skb);
1242 } else {
1243 skb_free_head(skb);
1244 }
1245 off = (data + nhead) - skb->head;
1246
1247 skb->head = data;
1248 skb->head_frag = 0;
1249 skb->data += off;
1250#ifdef NET_SKBUFF_DATA_USES_OFFSET
1251 skb->end = size;
1252 off = nhead;
1253#else
1254 skb->end = skb->head + size;
1255#endif
1256 skb->tail += off;
1257 skb_headers_offset_update(skb, nhead);
1258 skb->cloned = 0;
1259 skb->hdr_len = 0;
1260 skb->nohdr = 0;
1261 atomic_set(&skb_shinfo(skb)->dataref, 1);
1262 return 0;
1263
1264nofrags:
1265 kfree(data);
1266nodata:
1267 return -ENOMEM;
1268}
1269EXPORT_SYMBOL(pskb_expand_head);
1270
1271/* Make private copy of skb with writable head and some headroom */
1272
1273struct sk_buff *skb_realloc_headroom(struct sk_buff *skb, unsigned int headroom)
1274{
1275 struct sk_buff *skb2;
1276 int delta = headroom - skb_headroom(skb);
1277
1278 if (delta <= 0)
1279 skb2 = pskb_copy(skb, GFP_ATOMIC);
1280 else {
1281 skb2 = skb_clone(skb, GFP_ATOMIC);
1282 if (skb2 && pskb_expand_head(skb2, SKB_DATA_ALIGN(delta), 0,
1283 GFP_ATOMIC)) {
1284 kfree_skb(skb2);
1285 skb2 = NULL;
1286 }
1287 }
1288 return skb2;
1289}
1290EXPORT_SYMBOL(skb_realloc_headroom);
1291
1292/**
1293 * skb_copy_expand - copy and expand sk_buff
1294 * @skb: buffer to copy
1295 * @newheadroom: new free bytes at head
1296 * @newtailroom: new free bytes at tail
1297 * @gfp_mask: allocation priority
1298 *
1299 * Make a copy of both an &sk_buff and its data and while doing so
1300 * allocate additional space.
1301 *
1302 * This is used when the caller wishes to modify the data and needs a
1303 * private copy of the data to alter as well as more space for new fields.
1304 * Returns %NULL on failure or the pointer to the buffer
1305 * on success. The returned buffer has a reference count of 1.
1306 *
1307 * You must pass %GFP_ATOMIC as the allocation priority if this function
1308 * is called from an interrupt.
1309 */
1310struct sk_buff *skb_copy_expand(const struct sk_buff *skb,
1311 int newheadroom, int newtailroom,
1312 gfp_t gfp_mask)
1313{
1314 /*
1315 * Allocate the copy buffer
1316 */
1317 struct sk_buff *n = __alloc_skb(newheadroom + skb->len + newtailroom,
1318 gfp_mask, skb_alloc_rx_flag(skb),
1319 NUMA_NO_NODE);
1320 int oldheadroom = skb_headroom(skb);
1321 int head_copy_len, head_copy_off;
1322
1323 if (!n)
1324 return NULL;
1325
1326 skb_reserve(n, newheadroom);
1327
1328 /* Set the tail pointer and length */
1329 skb_put(n, skb->len);
1330
1331 head_copy_len = oldheadroom;
1332 head_copy_off = 0;
1333 if (newheadroom <= head_copy_len)
1334 head_copy_len = newheadroom;
1335 else
1336 head_copy_off = newheadroom - head_copy_len;
1337
1338 /* Copy the linear header and data. */
1339 if (skb_copy_bits(skb, -head_copy_len, n->head + head_copy_off,
1340 skb->len + head_copy_len))
1341 BUG();
1342
1343 copy_skb_header(n, skb);
1344
1345 skb_headers_offset_update(n, newheadroom - oldheadroom);
1346
1347 return n;
1348}
1349EXPORT_SYMBOL(skb_copy_expand);
1350
1351/**
1352 * skb_pad - zero pad the tail of an skb
1353 * @skb: buffer to pad
1354 * @pad: space to pad
1355 *
1356 * Ensure that a buffer is followed by a padding area that is zero
1357 * filled. Used by network drivers which may DMA or transfer data
1358 * beyond the buffer end onto the wire.
1359 *
1360 * May return error in out of memory cases. The skb is freed on error.
1361 */
1362
1363int skb_pad(struct sk_buff *skb, int pad)
1364{
1365 int err;
1366 int ntail;
1367
1368 /* If the skbuff is non linear tailroom is always zero.. */
1369 if (!skb_cloned(skb) && skb_tailroom(skb) >= pad) {
1370 memset(skb->data+skb->len, 0, pad);
1371 return 0;
1372 }
1373
1374 ntail = skb->data_len + pad - (skb->end - skb->tail);
1375 if (likely(skb_cloned(skb) || ntail > 0)) {
1376 err = pskb_expand_head(skb, 0, ntail, GFP_ATOMIC);
1377 if (unlikely(err))
1378 goto free_skb;
1379 }
1380
1381 /* FIXME: The use of this function with non-linear skb's really needs
1382 * to be audited.
1383 */
1384 err = skb_linearize(skb);
1385 if (unlikely(err))
1386 goto free_skb;
1387
1388 memset(skb->data + skb->len, 0, pad);
1389 return 0;
1390
1391free_skb:
1392 kfree_skb(skb);
1393 return err;
1394}
1395EXPORT_SYMBOL(skb_pad);
1396
1397/**
1398 * pskb_put - add data to the tail of a potentially fragmented buffer
1399 * @skb: start of the buffer to use
1400 * @tail: tail fragment of the buffer to use
1401 * @len: amount of data to add
1402 *
1403 * This function extends the used data area of the potentially
1404 * fragmented buffer. @tail must be the last fragment of @skb -- or
1405 * @skb itself. If this would exceed the total buffer size the kernel
1406 * will panic. A pointer to the first byte of the extra data is
1407 * returned.
1408 */
1409
1410unsigned char *pskb_put(struct sk_buff *skb, struct sk_buff *tail, int len)
1411{
1412 if (tail != skb) {
1413 skb->data_len += len;
1414 skb->len += len;
1415 }
1416 return skb_put(tail, len);
1417}
1418EXPORT_SYMBOL_GPL(pskb_put);
1419
1420/**
1421 * skb_put - add data to a buffer
1422 * @skb: buffer to use
1423 * @len: amount of data to add
1424 *
1425 * This function extends the used data area of the buffer. If this would
1426 * exceed the total buffer size the kernel will panic. A pointer to the
1427 * first byte of the extra data is returned.
1428 */
1429unsigned char *skb_put(struct sk_buff *skb, unsigned int len)
1430{
1431 unsigned char *tmp = skb_tail_pointer(skb);
1432 SKB_LINEAR_ASSERT(skb);
1433 skb->tail += len;
1434 skb->len += len;
1435 if (unlikely(skb->tail > skb->end))
1436 skb_over_panic(skb, len, __builtin_return_address(0));
1437 return tmp;
1438}
1439EXPORT_SYMBOL(skb_put);
1440
1441/**
1442 * skb_push - add data to the start of a buffer
1443 * @skb: buffer to use
1444 * @len: amount of data to add
1445 *
1446 * This function extends the used data area of the buffer at the buffer
1447 * start. If this would exceed the total buffer headroom the kernel will
1448 * panic. A pointer to the first byte of the extra data is returned.
1449 */
1450unsigned char *skb_push(struct sk_buff *skb, unsigned int len)
1451{
1452 skb->data -= len;
1453 skb->len += len;
1454 if (unlikely(skb->data<skb->head))
1455 skb_under_panic(skb, len, __builtin_return_address(0));
1456 return skb->data;
1457}
1458EXPORT_SYMBOL(skb_push);
1459
1460/**
1461 * skb_pull - remove data from the start of a buffer
1462 * @skb: buffer to use
1463 * @len: amount of data to remove
1464 *
1465 * This function removes data from the start of a buffer, returning
1466 * the memory to the headroom. A pointer to the next data in the buffer
1467 * is returned. Once the data has been pulled future pushes will overwrite
1468 * the old data.
1469 */
1470unsigned char *skb_pull(struct sk_buff *skb, unsigned int len)
1471{
1472 return skb_pull_inline(skb, len);
1473}
1474EXPORT_SYMBOL(skb_pull);
1475
1476/**
1477 * skb_trim - remove end from a buffer
1478 * @skb: buffer to alter
1479 * @len: new length
1480 *
1481 * Cut the length of a buffer down by removing data from the tail. If
1482 * the buffer is already under the length specified it is not modified.
1483 * The skb must be linear.
1484 */
1485void skb_trim(struct sk_buff *skb, unsigned int len)
1486{
1487 if (skb->len > len)
1488 __skb_trim(skb, len);
1489}
1490EXPORT_SYMBOL(skb_trim);
1491
1492/* Trims skb to length len. It can change skb pointers.
1493 */
1494
1495int ___pskb_trim(struct sk_buff *skb, unsigned int len)
1496{
1497 struct sk_buff **fragp;
1498 struct sk_buff *frag;
1499 int offset = skb_headlen(skb);
1500 int nfrags = skb_shinfo(skb)->nr_frags;
1501 int i;
1502 int err;
1503
1504 if (skb_cloned(skb) &&
1505 unlikely((err = pskb_expand_head(skb, 0, 0, GFP_ATOMIC))))
1506 return err;
1507
1508 i = 0;
1509 if (offset >= len)
1510 goto drop_pages;
1511
1512 for (; i < nfrags; i++) {
1513 int end = offset + skb_frag_size(&skb_shinfo(skb)->frags[i]);
1514
1515 if (end < len) {
1516 offset = end;
1517 continue;
1518 }
1519
1520 skb_frag_size_set(&skb_shinfo(skb)->frags[i++], len - offset);
1521
1522drop_pages:
1523 skb_shinfo(skb)->nr_frags = i;
1524
1525 for (; i < nfrags; i++)
1526 skb_frag_unref(skb, i);
1527
1528 if (skb_has_frag_list(skb))
1529 skb_drop_fraglist(skb);
1530 goto done;
1531 }
1532
1533 for (fragp = &skb_shinfo(skb)->frag_list; (frag = *fragp);
1534 fragp = &frag->next) {
1535 int end = offset + frag->len;
1536
1537 if (skb_shared(frag)) {
1538 struct sk_buff *nfrag;
1539
1540 nfrag = skb_clone(frag, GFP_ATOMIC);
1541 if (unlikely(!nfrag))
1542 return -ENOMEM;
1543
1544 nfrag->next = frag->next;
1545 consume_skb(frag);
1546 frag = nfrag;
1547 *fragp = frag;
1548 }
1549
1550 if (end < len) {
1551 offset = end;
1552 continue;
1553 }
1554
1555 if (end > len &&
1556 unlikely((err = pskb_trim(frag, len - offset))))
1557 return err;
1558
1559 if (frag->next)
1560 skb_drop_list(&frag->next);
1561 break;
1562 }
1563
1564done:
1565 if (len > skb_headlen(skb)) {
1566 skb->data_len -= skb->len - len;
1567 skb->len = len;
1568 } else {
1569 skb->len = len;
1570 skb->data_len = 0;
1571 skb_set_tail_pointer(skb, len);
1572 }
1573
1574 return 0;
1575}
1576EXPORT_SYMBOL(___pskb_trim);
1577
1578/**
1579 * __pskb_pull_tail - advance tail of skb header
1580 * @skb: buffer to reallocate
1581 * @delta: number of bytes to advance tail
1582 *
1583 * The function makes a sense only on a fragmented &sk_buff,
1584 * it expands header moving its tail forward and copying necessary
1585 * data from fragmented part.
1586 *
1587 * &sk_buff MUST have reference count of 1.
1588 *
1589 * Returns %NULL (and &sk_buff does not change) if pull failed
1590 * or value of new tail of skb in the case of success.
1591 *
1592 * All the pointers pointing into skb header may change and must be
1593 * reloaded after call to this function.
1594 */
1595
1596/* Moves tail of skb head forward, copying data from fragmented part,
1597 * when it is necessary.
1598 * 1. It may fail due to malloc failure.
1599 * 2. It may change skb pointers.
1600 *
1601 * It is pretty complicated. Luckily, it is called only in exceptional cases.
1602 */
1603unsigned char *__pskb_pull_tail(struct sk_buff *skb, int delta)
1604{
1605 /* If skb has not enough free space at tail, get new one
1606 * plus 128 bytes for future expansions. If we have enough
1607 * room at tail, reallocate without expansion only if skb is cloned.
1608 */
1609 int i, k, eat = (skb->tail + delta) - skb->end;
1610
1611 if (eat > 0 || skb_cloned(skb)) {
1612 if (pskb_expand_head(skb, 0, eat > 0 ? eat + 128 : 0,
1613 GFP_ATOMIC))
1614 return NULL;
1615 }
1616
1617 if (skb_copy_bits(skb, skb_headlen(skb), skb_tail_pointer(skb), delta))
1618 BUG();
1619
1620 /* Optimization: no fragments, no reasons to preestimate
1621 * size of pulled pages. Superb.
1622 */
1623 if (!skb_has_frag_list(skb))
1624 goto pull_pages;
1625
1626 /* Estimate size of pulled pages. */
1627 eat = delta;
1628 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
1629 int size = skb_frag_size(&skb_shinfo(skb)->frags[i]);
1630
1631 if (size >= eat)
1632 goto pull_pages;
1633 eat -= size;
1634 }
1635
1636 /* If we need update frag list, we are in troubles.
1637 * Certainly, it possible to add an offset to skb data,
1638 * but taking into account that pulling is expected to
1639 * be very rare operation, it is worth to fight against
1640 * further bloating skb head and crucify ourselves here instead.
1641 * Pure masohism, indeed. 8)8)
1642 */
1643 if (eat) {
1644 struct sk_buff *list = skb_shinfo(skb)->frag_list;
1645 struct sk_buff *clone = NULL;
1646 struct sk_buff *insp = NULL;
1647
1648 do {
1649 BUG_ON(!list);
1650
1651 if (list->len <= eat) {
1652 /* Eaten as whole. */
1653 eat -= list->len;
1654 list = list->next;
1655 insp = list;
1656 } else {
1657 /* Eaten partially. */
1658
1659 if (skb_shared(list)) {
1660 /* Sucks! We need to fork list. :-( */
1661 clone = skb_clone(list, GFP_ATOMIC);
1662 if (!clone)
1663 return NULL;
1664 insp = list->next;
1665 list = clone;
1666 } else {
1667 /* This may be pulled without
1668 * problems. */
1669 insp = list;
1670 }
1671 if (!pskb_pull(list, eat)) {
1672 kfree_skb(clone);
1673 return NULL;
1674 }
1675 break;
1676 }
1677 } while (eat);
1678
1679 /* Free pulled out fragments. */
1680 while ((list = skb_shinfo(skb)->frag_list) != insp) {
1681 skb_shinfo(skb)->frag_list = list->next;
1682 kfree_skb(list);
1683 }
1684 /* And insert new clone at head. */
1685 if (clone) {
1686 clone->next = list;
1687 skb_shinfo(skb)->frag_list = clone;
1688 }
1689 }
1690 /* Success! Now we may commit changes to skb data. */
1691
1692pull_pages:
1693 eat = delta;
1694 k = 0;
1695 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
1696 int size = skb_frag_size(&skb_shinfo(skb)->frags[i]);
1697
1698 if (size <= eat) {
1699 skb_frag_unref(skb, i);
1700 eat -= size;
1701 } else {
1702 skb_shinfo(skb)->frags[k] = skb_shinfo(skb)->frags[i];
1703 if (eat) {
1704 skb_shinfo(skb)->frags[k].page_offset += eat;
1705 skb_frag_size_sub(&skb_shinfo(skb)->frags[k], eat);
1706 eat = 0;
1707 }
1708 k++;
1709 }
1710 }
1711 skb_shinfo(skb)->nr_frags = k;
1712
1713 skb->tail += delta;
1714 skb->data_len -= delta;
1715
1716 return skb_tail_pointer(skb);
1717}
1718EXPORT_SYMBOL(__pskb_pull_tail);
1719
1720/**
1721 * skb_copy_bits - copy bits from skb to kernel buffer
1722 * @skb: source skb
1723 * @offset: offset in source
1724 * @to: destination buffer
1725 * @len: number of bytes to copy
1726 *
1727 * Copy the specified number of bytes from the source skb to the
1728 * destination buffer.
1729 *
1730 * CAUTION ! :
1731 * If its prototype is ever changed,
1732 * check arch/{*}/net/{*}.S files,
1733 * since it is called from BPF assembly code.
1734 */
1735int skb_copy_bits(const struct sk_buff *skb, int offset, void *to, int len)
1736{
1737 int start = skb_headlen(skb);
1738 struct sk_buff *frag_iter;
1739 int i, copy;
1740
1741 if (offset > (int)skb->len - len)
1742 goto fault;
1743
1744 /* Copy header. */
1745 if ((copy = start - offset) > 0) {
1746 if (copy > len)
1747 copy = len;
1748 skb_copy_from_linear_data_offset(skb, offset, to, copy);
1749 if ((len -= copy) == 0)
1750 return 0;
1751 offset += copy;
1752 to += copy;
1753 }
1754
1755 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
1756 int end;
1757 skb_frag_t *f = &skb_shinfo(skb)->frags[i];
1758
1759 WARN_ON(start > offset + len);
1760
1761 end = start + skb_frag_size(f);
1762 if ((copy = end - offset) > 0) {
1763 u8 *vaddr;
1764
1765 if (copy > len)
1766 copy = len;
1767
1768 vaddr = kmap_atomic(skb_frag_page(f));
1769 memcpy(to,
1770 vaddr + f->page_offset + offset - start,
1771 copy);
1772 kunmap_atomic(vaddr);
1773
1774 if ((len -= copy) == 0)
1775 return 0;
1776 offset += copy;
1777 to += copy;
1778 }
1779 start = end;
1780 }
1781
1782 skb_walk_frags(skb, frag_iter) {
1783 int end;
1784
1785 WARN_ON(start > offset + len);
1786
1787 end = start + frag_iter->len;
1788 if ((copy = end - offset) > 0) {
1789 if (copy > len)
1790 copy = len;
1791 if (skb_copy_bits(frag_iter, offset - start, to, copy))
1792 goto fault;
1793 if ((len -= copy) == 0)
1794 return 0;
1795 offset += copy;
1796 to += copy;
1797 }
1798 start = end;
1799 }
1800
1801 if (!len)
1802 return 0;
1803
1804fault:
1805 return -EFAULT;
1806}
1807EXPORT_SYMBOL(skb_copy_bits);
1808
1809/*
1810 * Callback from splice_to_pipe(), if we need to release some pages
1811 * at the end of the spd in case we error'ed out in filling the pipe.
1812 */
1813static void sock_spd_release(struct splice_pipe_desc *spd, unsigned int i)
1814{
1815 put_page(spd->pages[i]);
1816}
1817
1818static struct page *linear_to_page(struct page *page, unsigned int *len,
1819 unsigned int *offset,
1820 struct sock *sk)
1821{
1822 struct page_frag *pfrag = sk_page_frag(sk);
1823
1824 if (!sk_page_frag_refill(sk, pfrag))
1825 return NULL;
1826
1827 *len = min_t(unsigned int, *len, pfrag->size - pfrag->offset);
1828
1829 memcpy(page_address(pfrag->page) + pfrag->offset,
1830 page_address(page) + *offset, *len);
1831 *offset = pfrag->offset;
1832 pfrag->offset += *len;
1833
1834 return pfrag->page;
1835}
1836
1837static bool spd_can_coalesce(const struct splice_pipe_desc *spd,
1838 struct page *page,
1839 unsigned int offset)
1840{
1841 return spd->nr_pages &&
1842 spd->pages[spd->nr_pages - 1] == page &&
1843 (spd->partial[spd->nr_pages - 1].offset +
1844 spd->partial[spd->nr_pages - 1].len == offset);
1845}
1846
1847/*
1848 * Fill page/offset/length into spd, if it can hold more pages.
1849 */
1850static bool spd_fill_page(struct splice_pipe_desc *spd,
1851 struct pipe_inode_info *pipe, struct page *page,
1852 unsigned int *len, unsigned int offset,
1853 bool linear,
1854 struct sock *sk)
1855{
1856 if (unlikely(spd->nr_pages == MAX_SKB_FRAGS))
1857 return true;
1858
1859 if (linear) {
1860 page = linear_to_page(page, len, &offset, sk);
1861 if (!page)
1862 return true;
1863 }
1864 if (spd_can_coalesce(spd, page, offset)) {
1865 spd->partial[spd->nr_pages - 1].len += *len;
1866 return false;
1867 }
1868 get_page(page);
1869 spd->pages[spd->nr_pages] = page;
1870 spd->partial[spd->nr_pages].len = *len;
1871 spd->partial[spd->nr_pages].offset = offset;
1872 spd->nr_pages++;
1873
1874 return false;
1875}
1876
1877static bool __splice_segment(struct page *page, unsigned int poff,
1878 unsigned int plen, unsigned int *off,
1879 unsigned int *len,
1880 struct splice_pipe_desc *spd, bool linear,
1881 struct sock *sk,
1882 struct pipe_inode_info *pipe)
1883{
1884 if (!*len)
1885 return true;
1886
1887 /* skip this segment if already processed */
1888 if (*off >= plen) {
1889 *off -= plen;
1890 return false;
1891 }
1892
1893 /* ignore any bits we already processed */
1894 poff += *off;
1895 plen -= *off;
1896 *off = 0;
1897
1898 do {
1899 unsigned int flen = min(*len, plen);
1900
1901 if (spd_fill_page(spd, pipe, page, &flen, poff,
1902 linear, sk))
1903 return true;
1904 poff += flen;
1905 plen -= flen;
1906 *len -= flen;
1907 } while (*len && plen);
1908
1909 return false;
1910}
1911
1912/*
1913 * Map linear and fragment data from the skb to spd. It reports true if the
1914 * pipe is full or if we already spliced the requested length.
1915 */
1916static bool __skb_splice_bits(struct sk_buff *skb, struct pipe_inode_info *pipe,
1917 unsigned int *offset, unsigned int *len,
1918 struct splice_pipe_desc *spd, struct sock *sk)
1919{
1920 int seg;
1921 struct sk_buff *iter;
1922
1923 /* map the linear part :
1924 * If skb->head_frag is set, this 'linear' part is backed by a
1925 * fragment, and if the head is not shared with any clones then
1926 * we can avoid a copy since we own the head portion of this page.
1927 */
1928 if (__splice_segment(virt_to_page(skb->data),
1929 (unsigned long) skb->data & (PAGE_SIZE - 1),
1930 skb_headlen(skb),
1931 offset, len, spd,
1932 skb_head_is_locked(skb),
1933 sk, pipe))
1934 return true;
1935
1936 /*
1937 * then map the fragments
1938 */
1939 for (seg = 0; seg < skb_shinfo(skb)->nr_frags; seg++) {
1940 const skb_frag_t *f = &skb_shinfo(skb)->frags[seg];
1941
1942 if (__splice_segment(skb_frag_page(f),
1943 f->page_offset, skb_frag_size(f),
1944 offset, len, spd, false, sk, pipe))
1945 return true;
1946 }
1947
1948 skb_walk_frags(skb, iter) {
1949 if (*offset >= iter->len) {
1950 *offset -= iter->len;
1951 continue;
1952 }
1953 /* __skb_splice_bits() only fails if the output has no room
1954 * left, so no point in going over the frag_list for the error
1955 * case.
1956 */
1957 if (__skb_splice_bits(iter, pipe, offset, len, spd, sk))
1958 return true;
1959 }
1960
1961 return false;
1962}
1963
1964ssize_t skb_socket_splice(struct sock *sk,
1965 struct pipe_inode_info *pipe,
1966 struct splice_pipe_desc *spd)
1967{
1968 int ret;
1969
1970 /* Drop the socket lock, otherwise we have reverse
1971 * locking dependencies between sk_lock and i_mutex
1972 * here as compared to sendfile(). We enter here
1973 * with the socket lock held, and splice_to_pipe() will
1974 * grab the pipe inode lock. For sendfile() emulation,
1975 * we call into ->sendpage() with the i_mutex lock held
1976 * and networking will grab the socket lock.
1977 */
1978 release_sock(sk);
1979 ret = splice_to_pipe(pipe, spd);
1980 lock_sock(sk);
1981
1982 return ret;
1983}
1984
1985/*
1986 * Map data from the skb to a pipe. Should handle both the linear part,
1987 * the fragments, and the frag list.
1988 */
1989int skb_splice_bits(struct sk_buff *skb, struct sock *sk, unsigned int offset,
1990 struct pipe_inode_info *pipe, unsigned int tlen,
1991 unsigned int flags,
1992 ssize_t (*splice_cb)(struct sock *,
1993 struct pipe_inode_info *,
1994 struct splice_pipe_desc *))
1995{
1996 struct partial_page partial[MAX_SKB_FRAGS];
1997 struct page *pages[MAX_SKB_FRAGS];
1998 struct splice_pipe_desc spd = {
1999 .pages = pages,
2000 .partial = partial,
2001 .nr_pages_max = MAX_SKB_FRAGS,
2002 .flags = flags,
2003 .ops = &nosteal_pipe_buf_ops,
2004 .spd_release = sock_spd_release,
2005 };
2006 int ret = 0;
2007
2008 __skb_splice_bits(skb, pipe, &offset, &tlen, &spd, sk);
2009
2010 if (spd.nr_pages)
2011 ret = splice_cb(sk, pipe, &spd);
2012
2013 return ret;
2014}
2015EXPORT_SYMBOL_GPL(skb_splice_bits);
2016
2017/**
2018 * skb_store_bits - store bits from kernel buffer to skb
2019 * @skb: destination buffer
2020 * @offset: offset in destination
2021 * @from: source buffer
2022 * @len: number of bytes to copy
2023 *
2024 * Copy the specified number of bytes from the source buffer to the
2025 * destination skb. This function handles all the messy bits of
2026 * traversing fragment lists and such.
2027 */
2028
2029int skb_store_bits(struct sk_buff *skb, int offset, const void *from, int len)
2030{
2031 int start = skb_headlen(skb);
2032 struct sk_buff *frag_iter;
2033 int i, copy;
2034
2035 if (offset > (int)skb->len - len)
2036 goto fault;
2037
2038 if ((copy = start - offset) > 0) {
2039 if (copy > len)
2040 copy = len;
2041 skb_copy_to_linear_data_offset(skb, offset, from, copy);
2042 if ((len -= copy) == 0)
2043 return 0;
2044 offset += copy;
2045 from += copy;
2046 }
2047
2048 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
2049 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
2050 int end;
2051
2052 WARN_ON(start > offset + len);
2053
2054 end = start + skb_frag_size(frag);
2055 if ((copy = end - offset) > 0) {
2056 u8 *vaddr;
2057
2058 if (copy > len)
2059 copy = len;
2060
2061 vaddr = kmap_atomic(skb_frag_page(frag));
2062 memcpy(vaddr + frag->page_offset + offset - start,
2063 from, copy);
2064 kunmap_atomic(vaddr);
2065
2066 if ((len -= copy) == 0)
2067 return 0;
2068 offset += copy;
2069 from += copy;
2070 }
2071 start = end;
2072 }
2073
2074 skb_walk_frags(skb, frag_iter) {
2075 int end;
2076
2077 WARN_ON(start > offset + len);
2078
2079 end = start + frag_iter->len;
2080 if ((copy = end - offset) > 0) {
2081 if (copy > len)
2082 copy = len;
2083 if (skb_store_bits(frag_iter, offset - start,
2084 from, copy))
2085 goto fault;
2086 if ((len -= copy) == 0)
2087 return 0;
2088 offset += copy;
2089 from += copy;
2090 }
2091 start = end;
2092 }
2093 if (!len)
2094 return 0;
2095
2096fault:
2097 return -EFAULT;
2098}
2099EXPORT_SYMBOL(skb_store_bits);
2100
2101/* Checksum skb data. */
2102__wsum __skb_checksum(const struct sk_buff *skb, int offset, int len,
2103 __wsum csum, const struct skb_checksum_ops *ops)
2104{
2105 int start = skb_headlen(skb);
2106 int i, copy = start - offset;
2107 struct sk_buff *frag_iter;
2108 int pos = 0;
2109
2110 /* Checksum header. */
2111 if (copy > 0) {
2112 if (copy > len)
2113 copy = len;
2114 csum = ops->update(skb->data + offset, copy, csum);
2115 if ((len -= copy) == 0)
2116 return csum;
2117 offset += copy;
2118 pos = copy;
2119 }
2120
2121 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
2122 int end;
2123 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
2124
2125 WARN_ON(start > offset + len);
2126
2127 end = start + skb_frag_size(frag);
2128 if ((copy = end - offset) > 0) {
2129 __wsum csum2;
2130 u8 *vaddr;
2131
2132 if (copy > len)
2133 copy = len;
2134 vaddr = kmap_atomic(skb_frag_page(frag));
2135 csum2 = ops->update(vaddr + frag->page_offset +
2136 offset - start, copy, 0);
2137 kunmap_atomic(vaddr);
2138 csum = ops->combine(csum, csum2, pos, copy);
2139 if (!(len -= copy))
2140 return csum;
2141 offset += copy;
2142 pos += copy;
2143 }
2144 start = end;
2145 }
2146
2147 skb_walk_frags(skb, frag_iter) {
2148 int end;
2149
2150 WARN_ON(start > offset + len);
2151
2152 end = start + frag_iter->len;
2153 if ((copy = end - offset) > 0) {
2154 __wsum csum2;
2155 if (copy > len)
2156 copy = len;
2157 csum2 = __skb_checksum(frag_iter, offset - start,
2158 copy, 0, ops);
2159 csum = ops->combine(csum, csum2, pos, copy);
2160 if ((len -= copy) == 0)
2161 return csum;
2162 offset += copy;
2163 pos += copy;
2164 }
2165 start = end;
2166 }
2167 BUG_ON(len);
2168
2169 return csum;
2170}
2171EXPORT_SYMBOL(__skb_checksum);
2172
2173__wsum skb_checksum(const struct sk_buff *skb, int offset,
2174 int len, __wsum csum)
2175{
2176 const struct skb_checksum_ops ops = {
2177 .update = csum_partial_ext,
2178 .combine = csum_block_add_ext,
2179 };
2180
2181 return __skb_checksum(skb, offset, len, csum, &ops);
2182}
2183EXPORT_SYMBOL(skb_checksum);
2184
2185/* Both of above in one bottle. */
2186
2187__wsum skb_copy_and_csum_bits(const struct sk_buff *skb, int offset,
2188 u8 *to, int len, __wsum csum)
2189{
2190 int start = skb_headlen(skb);
2191 int i, copy = start - offset;
2192 struct sk_buff *frag_iter;
2193 int pos = 0;
2194
2195 /* Copy header. */
2196 if (copy > 0) {
2197 if (copy > len)
2198 copy = len;
2199 csum = csum_partial_copy_nocheck(skb->data + offset, to,
2200 copy, csum);
2201 if ((len -= copy) == 0)
2202 return csum;
2203 offset += copy;
2204 to += copy;
2205 pos = copy;
2206 }
2207
2208 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
2209 int end;
2210
2211 WARN_ON(start > offset + len);
2212
2213 end = start + skb_frag_size(&skb_shinfo(skb)->frags[i]);
2214 if ((copy = end - offset) > 0) {
2215 __wsum csum2;
2216 u8 *vaddr;
2217 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
2218
2219 if (copy > len)
2220 copy = len;
2221 vaddr = kmap_atomic(skb_frag_page(frag));
2222 csum2 = csum_partial_copy_nocheck(vaddr +
2223 frag->page_offset +
2224 offset - start, to,
2225 copy, 0);
2226 kunmap_atomic(vaddr);
2227 csum = csum_block_add(csum, csum2, pos);
2228 if (!(len -= copy))
2229 return csum;
2230 offset += copy;
2231 to += copy;
2232 pos += copy;
2233 }
2234 start = end;
2235 }
2236
2237 skb_walk_frags(skb, frag_iter) {
2238 __wsum csum2;
2239 int end;
2240
2241 WARN_ON(start > offset + len);
2242
2243 end = start + frag_iter->len;
2244 if ((copy = end - offset) > 0) {
2245 if (copy > len)
2246 copy = len;
2247 csum2 = skb_copy_and_csum_bits(frag_iter,
2248 offset - start,
2249 to, copy, 0);
2250 csum = csum_block_add(csum, csum2, pos);
2251 if ((len -= copy) == 0)
2252 return csum;
2253 offset += copy;
2254 to += copy;
2255 pos += copy;
2256 }
2257 start = end;
2258 }
2259 BUG_ON(len);
2260 return csum;
2261}
2262EXPORT_SYMBOL(skb_copy_and_csum_bits);
2263
2264 /**
2265 * skb_zerocopy_headlen - Calculate headroom needed for skb_zerocopy()
2266 * @from: source buffer
2267 *
2268 * Calculates the amount of linear headroom needed in the 'to' skb passed
2269 * into skb_zerocopy().
2270 */
2271unsigned int
2272skb_zerocopy_headlen(const struct sk_buff *from)
2273{
2274 unsigned int hlen = 0;
2275
2276 if (!from->head_frag ||
2277 skb_headlen(from) < L1_CACHE_BYTES ||
2278 skb_shinfo(from)->nr_frags >= MAX_SKB_FRAGS)
2279 hlen = skb_headlen(from);
2280
2281 if (skb_has_frag_list(from))
2282 hlen = from->len;
2283
2284 return hlen;
2285}
2286EXPORT_SYMBOL_GPL(skb_zerocopy_headlen);
2287
2288/**
2289 * skb_zerocopy - Zero copy skb to skb
2290 * @to: destination buffer
2291 * @from: source buffer
2292 * @len: number of bytes to copy from source buffer
2293 * @hlen: size of linear headroom in destination buffer
2294 *
2295 * Copies up to `len` bytes from `from` to `to` by creating references
2296 * to the frags in the source buffer.
2297 *
2298 * The `hlen` as calculated by skb_zerocopy_headlen() specifies the
2299 * headroom in the `to` buffer.
2300 *
2301 * Return value:
2302 * 0: everything is OK
2303 * -ENOMEM: couldn't orphan frags of @from due to lack of memory
2304 * -EFAULT: skb_copy_bits() found some problem with skb geometry
2305 */
2306int
2307skb_zerocopy(struct sk_buff *to, struct sk_buff *from, int len, int hlen)
2308{
2309 int i, j = 0;
2310 int plen = 0; /* length of skb->head fragment */
2311 int ret;
2312 struct page *page;
2313 unsigned int offset;
2314
2315 BUG_ON(!from->head_frag && !hlen);
2316
2317 /* dont bother with small payloads */
2318 if (len <= skb_tailroom(to))
2319 return skb_copy_bits(from, 0, skb_put(to, len), len);
2320
2321 if (hlen) {
2322 ret = skb_copy_bits(from, 0, skb_put(to, hlen), hlen);
2323 if (unlikely(ret))
2324 return ret;
2325 len -= hlen;
2326 } else {
2327 plen = min_t(int, skb_headlen(from), len);
2328 if (plen) {
2329 page = virt_to_head_page(from->head);
2330 offset = from->data - (unsigned char *)page_address(page);
2331 __skb_fill_page_desc(to, 0, page, offset, plen);
2332 get_page(page);
2333 j = 1;
2334 len -= plen;
2335 }
2336 }
2337
2338 to->truesize += len + plen;
2339 to->len += len + plen;
2340 to->data_len += len + plen;
2341
2342 if (unlikely(skb_orphan_frags(from, GFP_ATOMIC))) {
2343 skb_tx_error(from);
2344 return -ENOMEM;
2345 }
2346
2347 for (i = 0; i < skb_shinfo(from)->nr_frags; i++) {
2348 if (!len)
2349 break;
2350 skb_shinfo(to)->frags[j] = skb_shinfo(from)->frags[i];
2351 skb_shinfo(to)->frags[j].size = min_t(int, skb_shinfo(to)->frags[j].size, len);
2352 len -= skb_shinfo(to)->frags[j].size;
2353 skb_frag_ref(to, j);
2354 j++;
2355 }
2356 skb_shinfo(to)->nr_frags = j;
2357
2358 return 0;
2359}
2360EXPORT_SYMBOL_GPL(skb_zerocopy);
2361
2362void skb_copy_and_csum_dev(const struct sk_buff *skb, u8 *to)
2363{
2364 __wsum csum;
2365 long csstart;
2366
2367 if (skb->ip_summed == CHECKSUM_PARTIAL)
2368 csstart = skb_checksum_start_offset(skb);
2369 else
2370 csstart = skb_headlen(skb);
2371
2372 BUG_ON(csstart > skb_headlen(skb));
2373
2374 skb_copy_from_linear_data(skb, to, csstart);
2375
2376 csum = 0;
2377 if (csstart != skb->len)
2378 csum = skb_copy_and_csum_bits(skb, csstart, to + csstart,
2379 skb->len - csstart, 0);
2380
2381 if (skb->ip_summed == CHECKSUM_PARTIAL) {
2382 long csstuff = csstart + skb->csum_offset;
2383
2384 *((__sum16 *)(to + csstuff)) = csum_fold(csum);
2385 }
2386}
2387EXPORT_SYMBOL(skb_copy_and_csum_dev);
2388
2389/**
2390 * skb_dequeue - remove from the head of the queue
2391 * @list: list to dequeue from
2392 *
2393 * Remove the head of the list. The list lock is taken so the function
2394 * may be used safely with other locking list functions. The head item is
2395 * returned or %NULL if the list is empty.
2396 */
2397
2398struct sk_buff *skb_dequeue(struct sk_buff_head *list)
2399{
2400 unsigned long flags;
2401 struct sk_buff *result;
2402
2403 spin_lock_irqsave(&list->lock, flags);
2404 result = __skb_dequeue(list);
2405 spin_unlock_irqrestore(&list->lock, flags);
2406 return result;
2407}
2408EXPORT_SYMBOL(skb_dequeue);
2409
2410/**
2411 * skb_dequeue_tail - remove from the tail of the queue
2412 * @list: list to dequeue from
2413 *
2414 * Remove the tail of the list. The list lock is taken so the function
2415 * may be used safely with other locking list functions. The tail item is
2416 * returned or %NULL if the list is empty.
2417 */
2418struct sk_buff *skb_dequeue_tail(struct sk_buff_head *list)
2419{
2420 unsigned long flags;
2421 struct sk_buff *result;
2422
2423 spin_lock_irqsave(&list->lock, flags);
2424 result = __skb_dequeue_tail(list);
2425 spin_unlock_irqrestore(&list->lock, flags);
2426 return result;
2427}
2428EXPORT_SYMBOL(skb_dequeue_tail);
2429
2430/**
2431 * skb_queue_purge - empty a list
2432 * @list: list to empty
2433 *
2434 * Delete all buffers on an &sk_buff list. Each buffer is removed from
2435 * the list and one reference dropped. This function takes the list
2436 * lock and is atomic with respect to other list locking functions.
2437 */
2438void skb_queue_purge(struct sk_buff_head *list)
2439{
2440 struct sk_buff *skb;
2441 while ((skb = skb_dequeue(list)) != NULL)
2442 kfree_skb(skb);
2443}
2444EXPORT_SYMBOL(skb_queue_purge);
2445
2446/**
2447 * skb_queue_head - queue a buffer at the list head
2448 * @list: list to use
2449 * @newsk: buffer to queue
2450 *
2451 * Queue a buffer at the start of the list. This function takes the
2452 * list lock and can be used safely with other locking &sk_buff functions
2453 * safely.
2454 *
2455 * A buffer cannot be placed on two lists at the same time.
2456 */
2457void skb_queue_head(struct sk_buff_head *list, struct sk_buff *newsk)
2458{
2459 unsigned long flags;
2460
2461 spin_lock_irqsave(&list->lock, flags);
2462 __skb_queue_head(list, newsk);
2463 spin_unlock_irqrestore(&list->lock, flags);
2464}
2465EXPORT_SYMBOL(skb_queue_head);
2466
2467/**
2468 * skb_queue_tail - queue a buffer at the list tail
2469 * @list: list to use
2470 * @newsk: buffer to queue
2471 *
2472 * Queue a buffer at the tail of the list. This function takes the
2473 * list lock and can be used safely with other locking &sk_buff functions
2474 * safely.
2475 *
2476 * A buffer cannot be placed on two lists at the same time.
2477 */
2478void skb_queue_tail(struct sk_buff_head *list, struct sk_buff *newsk)
2479{
2480 unsigned long flags;
2481
2482 spin_lock_irqsave(&list->lock, flags);
2483 __skb_queue_tail(list, newsk);
2484 spin_unlock_irqrestore(&list->lock, flags);
2485}
2486EXPORT_SYMBOL(skb_queue_tail);
2487
2488/**
2489 * skb_unlink - remove a buffer from a list
2490 * @skb: buffer to remove
2491 * @list: list to use
2492 *
2493 * Remove a packet from a list. The list locks are taken and this
2494 * function is atomic with respect to other list locked calls
2495 *
2496 * You must know what list the SKB is on.
2497 */
2498void skb_unlink(struct sk_buff *skb, struct sk_buff_head *list)
2499{
2500 unsigned long flags;
2501
2502 spin_lock_irqsave(&list->lock, flags);
2503 __skb_unlink(skb, list);
2504 spin_unlock_irqrestore(&list->lock, flags);
2505}
2506EXPORT_SYMBOL(skb_unlink);
2507
2508/**
2509 * skb_append - append a buffer
2510 * @old: buffer to insert after
2511 * @newsk: buffer to insert
2512 * @list: list to use
2513 *
2514 * Place a packet after a given packet in a list. The list locks are taken
2515 * and this function is atomic with respect to other list locked calls.
2516 * A buffer cannot be placed on two lists at the same time.
2517 */
2518void skb_append(struct sk_buff *old, struct sk_buff *newsk, struct sk_buff_head *list)
2519{
2520 unsigned long flags;
2521
2522 spin_lock_irqsave(&list->lock, flags);
2523 __skb_queue_after(list, old, newsk);
2524 spin_unlock_irqrestore(&list->lock, flags);
2525}
2526EXPORT_SYMBOL(skb_append);
2527
2528/**
2529 * skb_insert - insert a buffer
2530 * @old: buffer to insert before
2531 * @newsk: buffer to insert
2532 * @list: list to use
2533 *
2534 * Place a packet before a given packet in a list. The list locks are
2535 * taken and this function is atomic with respect to other list locked
2536 * calls.
2537 *
2538 * A buffer cannot be placed on two lists at the same time.
2539 */
2540void skb_insert(struct sk_buff *old, struct sk_buff *newsk, struct sk_buff_head *list)
2541{
2542 unsigned long flags;
2543
2544 spin_lock_irqsave(&list->lock, flags);
2545 __skb_insert(newsk, old->prev, old, list);
2546 spin_unlock_irqrestore(&list->lock, flags);
2547}
2548EXPORT_SYMBOL(skb_insert);
2549
2550static inline void skb_split_inside_header(struct sk_buff *skb,
2551 struct sk_buff* skb1,
2552 const u32 len, const int pos)
2553{
2554 int i;
2555
2556 skb_copy_from_linear_data_offset(skb, len, skb_put(skb1, pos - len),
2557 pos - len);
2558 /* And move data appendix as is. */
2559 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
2560 skb_shinfo(skb1)->frags[i] = skb_shinfo(skb)->frags[i];
2561
2562 skb_shinfo(skb1)->nr_frags = skb_shinfo(skb)->nr_frags;
2563 skb_shinfo(skb)->nr_frags = 0;
2564 skb1->data_len = skb->data_len;
2565 skb1->len += skb1->data_len;
2566 skb->data_len = 0;
2567 skb->len = len;
2568 skb_set_tail_pointer(skb, len);
2569}
2570
2571static inline void skb_split_no_header(struct sk_buff *skb,
2572 struct sk_buff* skb1,
2573 const u32 len, int pos)
2574{
2575 int i, k = 0;
2576 const int nfrags = skb_shinfo(skb)->nr_frags;
2577
2578 skb_shinfo(skb)->nr_frags = 0;
2579 skb1->len = skb1->data_len = skb->len - len;
2580 skb->len = len;
2581 skb->data_len = len - pos;
2582
2583 for (i = 0; i < nfrags; i++) {
2584 int size = skb_frag_size(&skb_shinfo(skb)->frags[i]);
2585
2586 if (pos + size > len) {
2587 skb_shinfo(skb1)->frags[k] = skb_shinfo(skb)->frags[i];
2588
2589 if (pos < len) {
2590 /* Split frag.
2591 * We have two variants in this case:
2592 * 1. Move all the frag to the second
2593 * part, if it is possible. F.e.
2594 * this approach is mandatory for TUX,
2595 * where splitting is expensive.
2596 * 2. Split is accurately. We make this.
2597 */
2598 skb_frag_ref(skb, i);
2599 skb_shinfo(skb1)->frags[0].page_offset += len - pos;
2600 skb_frag_size_sub(&skb_shinfo(skb1)->frags[0], len - pos);
2601 skb_frag_size_set(&skb_shinfo(skb)->frags[i], len - pos);
2602 skb_shinfo(skb)->nr_frags++;
2603 }
2604 k++;
2605 } else
2606 skb_shinfo(skb)->nr_frags++;
2607 pos += size;
2608 }
2609 skb_shinfo(skb1)->nr_frags = k;
2610}
2611
2612/**
2613 * skb_split - Split fragmented skb to two parts at length len.
2614 * @skb: the buffer to split
2615 * @skb1: the buffer to receive the second part
2616 * @len: new length for skb
2617 */
2618void skb_split(struct sk_buff *skb, struct sk_buff *skb1, const u32 len)
2619{
2620 int pos = skb_headlen(skb);
2621
2622 skb_shinfo(skb1)->tx_flags = skb_shinfo(skb)->tx_flags & SKBTX_SHARED_FRAG;
2623 if (len < pos) /* Split line is inside header. */
2624 skb_split_inside_header(skb, skb1, len, pos);
2625 else /* Second chunk has no header, nothing to copy. */
2626 skb_split_no_header(skb, skb1, len, pos);
2627}
2628EXPORT_SYMBOL(skb_split);
2629
2630/* Shifting from/to a cloned skb is a no-go.
2631 *
2632 * Caller cannot keep skb_shinfo related pointers past calling here!
2633 */
2634static int skb_prepare_for_shift(struct sk_buff *skb)
2635{
2636 return skb_cloned(skb) && pskb_expand_head(skb, 0, 0, GFP_ATOMIC);
2637}
2638
2639/**
2640 * skb_shift - Shifts paged data partially from skb to another
2641 * @tgt: buffer into which tail data gets added
2642 * @skb: buffer from which the paged data comes from
2643 * @shiftlen: shift up to this many bytes
2644 *
2645 * Attempts to shift up to shiftlen worth of bytes, which may be less than
2646 * the length of the skb, from skb to tgt. Returns number bytes shifted.
2647 * It's up to caller to free skb if everything was shifted.
2648 *
2649 * If @tgt runs out of frags, the whole operation is aborted.
2650 *
2651 * Skb cannot include anything else but paged data while tgt is allowed
2652 * to have non-paged data as well.
2653 *
2654 * TODO: full sized shift could be optimized but that would need
2655 * specialized skb free'er to handle frags without up-to-date nr_frags.
2656 */
2657int skb_shift(struct sk_buff *tgt, struct sk_buff *skb, int shiftlen)
2658{
2659 int from, to, merge, todo;
2660 struct skb_frag_struct *fragfrom, *fragto;
2661
2662 BUG_ON(shiftlen > skb->len);
2663 BUG_ON(skb_headlen(skb)); /* Would corrupt stream */
2664
2665 todo = shiftlen;
2666 from = 0;
2667 to = skb_shinfo(tgt)->nr_frags;
2668 fragfrom = &skb_shinfo(skb)->frags[from];
2669
2670 /* Actual merge is delayed until the point when we know we can
2671 * commit all, so that we don't have to undo partial changes
2672 */
2673 if (!to ||
2674 !skb_can_coalesce(tgt, to, skb_frag_page(fragfrom),
2675 fragfrom->page_offset)) {
2676 merge = -1;
2677 } else {
2678 merge = to - 1;
2679
2680 todo -= skb_frag_size(fragfrom);
2681 if (todo < 0) {
2682 if (skb_prepare_for_shift(skb) ||
2683 skb_prepare_for_shift(tgt))
2684 return 0;
2685
2686 /* All previous frag pointers might be stale! */
2687 fragfrom = &skb_shinfo(skb)->frags[from];
2688 fragto = &skb_shinfo(tgt)->frags[merge];
2689
2690 skb_frag_size_add(fragto, shiftlen);
2691 skb_frag_size_sub(fragfrom, shiftlen);
2692 fragfrom->page_offset += shiftlen;
2693
2694 goto onlymerged;
2695 }
2696
2697 from++;
2698 }
2699
2700 /* Skip full, not-fitting skb to avoid expensive operations */
2701 if ((shiftlen == skb->len) &&
2702 (skb_shinfo(skb)->nr_frags - from) > (MAX_SKB_FRAGS - to))
2703 return 0;
2704
2705 if (skb_prepare_for_shift(skb) || skb_prepare_for_shift(tgt))
2706 return 0;
2707
2708 while ((todo > 0) && (from < skb_shinfo(skb)->nr_frags)) {
2709 if (to == MAX_SKB_FRAGS)
2710 return 0;
2711
2712 fragfrom = &skb_shinfo(skb)->frags[from];
2713 fragto = &skb_shinfo(tgt)->frags[to];
2714
2715 if (todo >= skb_frag_size(fragfrom)) {
2716 *fragto = *fragfrom;
2717 todo -= skb_frag_size(fragfrom);
2718 from++;
2719 to++;
2720
2721 } else {
2722 __skb_frag_ref(fragfrom);
2723 fragto->page = fragfrom->page;
2724 fragto->page_offset = fragfrom->page_offset;
2725 skb_frag_size_set(fragto, todo);
2726
2727 fragfrom->page_offset += todo;
2728 skb_frag_size_sub(fragfrom, todo);
2729 todo = 0;
2730
2731 to++;
2732 break;
2733 }
2734 }
2735
2736 /* Ready to "commit" this state change to tgt */
2737 skb_shinfo(tgt)->nr_frags = to;
2738
2739 if (merge >= 0) {
2740 fragfrom = &skb_shinfo(skb)->frags[0];
2741 fragto = &skb_shinfo(tgt)->frags[merge];
2742
2743 skb_frag_size_add(fragto, skb_frag_size(fragfrom));
2744 __skb_frag_unref(fragfrom);
2745 }
2746
2747 /* Reposition in the original skb */
2748 to = 0;
2749 while (from < skb_shinfo(skb)->nr_frags)
2750 skb_shinfo(skb)->frags[to++] = skb_shinfo(skb)->frags[from++];
2751 skb_shinfo(skb)->nr_frags = to;
2752
2753 BUG_ON(todo > 0 && !skb_shinfo(skb)->nr_frags);
2754
2755onlymerged:
2756 /* Most likely the tgt won't ever need its checksum anymore, skb on
2757 * the other hand might need it if it needs to be resent
2758 */
2759 tgt->ip_summed = CHECKSUM_PARTIAL;
2760 skb->ip_summed = CHECKSUM_PARTIAL;
2761
2762 /* Yak, is it really working this way? Some helper please? */
2763 skb->len -= shiftlen;
2764 skb->data_len -= shiftlen;
2765 skb->truesize -= shiftlen;
2766 tgt->len += shiftlen;
2767 tgt->data_len += shiftlen;
2768 tgt->truesize += shiftlen;
2769
2770 return shiftlen;
2771}
2772
2773/**
2774 * skb_prepare_seq_read - Prepare a sequential read of skb data
2775 * @skb: the buffer to read
2776 * @from: lower offset of data to be read
2777 * @to: upper offset of data to be read
2778 * @st: state variable
2779 *
2780 * Initializes the specified state variable. Must be called before
2781 * invoking skb_seq_read() for the first time.
2782 */
2783void skb_prepare_seq_read(struct sk_buff *skb, unsigned int from,
2784 unsigned int to, struct skb_seq_state *st)
2785{
2786 st->lower_offset = from;
2787 st->upper_offset = to;
2788 st->root_skb = st->cur_skb = skb;
2789 st->frag_idx = st->stepped_offset = 0;
2790 st->frag_data = NULL;
2791}
2792EXPORT_SYMBOL(skb_prepare_seq_read);
2793
2794/**
2795 * skb_seq_read - Sequentially read skb data
2796 * @consumed: number of bytes consumed by the caller so far
2797 * @data: destination pointer for data to be returned
2798 * @st: state variable
2799 *
2800 * Reads a block of skb data at @consumed relative to the
2801 * lower offset specified to skb_prepare_seq_read(). Assigns
2802 * the head of the data block to @data and returns the length
2803 * of the block or 0 if the end of the skb data or the upper
2804 * offset has been reached.
2805 *
2806 * The caller is not required to consume all of the data
2807 * returned, i.e. @consumed is typically set to the number
2808 * of bytes already consumed and the next call to
2809 * skb_seq_read() will return the remaining part of the block.
2810 *
2811 * Note 1: The size of each block of data returned can be arbitrary,
2812 * this limitation is the cost for zerocopy sequential
2813 * reads of potentially non linear data.
2814 *
2815 * Note 2: Fragment lists within fragments are not implemented
2816 * at the moment, state->root_skb could be replaced with
2817 * a stack for this purpose.
2818 */
2819unsigned int skb_seq_read(unsigned int consumed, const u8 **data,
2820 struct skb_seq_state *st)
2821{
2822 unsigned int block_limit, abs_offset = consumed + st->lower_offset;
2823 skb_frag_t *frag;
2824
2825 if (unlikely(abs_offset >= st->upper_offset)) {
2826 if (st->frag_data) {
2827 kunmap_atomic(st->frag_data);
2828 st->frag_data = NULL;
2829 }
2830 return 0;
2831 }
2832
2833next_skb:
2834 block_limit = skb_headlen(st->cur_skb) + st->stepped_offset;
2835
2836 if (abs_offset < block_limit && !st->frag_data) {
2837 *data = st->cur_skb->data + (abs_offset - st->stepped_offset);
2838 return block_limit - abs_offset;
2839 }
2840
2841 if (st->frag_idx == 0 && !st->frag_data)
2842 st->stepped_offset += skb_headlen(st->cur_skb);
2843
2844 while (st->frag_idx < skb_shinfo(st->cur_skb)->nr_frags) {
2845 frag = &skb_shinfo(st->cur_skb)->frags[st->frag_idx];
2846 block_limit = skb_frag_size(frag) + st->stepped_offset;
2847
2848 if (abs_offset < block_limit) {
2849 if (!st->frag_data)
2850 st->frag_data = kmap_atomic(skb_frag_page(frag));
2851
2852 *data = (u8 *) st->frag_data + frag->page_offset +
2853 (abs_offset - st->stepped_offset);
2854
2855 return block_limit - abs_offset;
2856 }
2857
2858 if (st->frag_data) {
2859 kunmap_atomic(st->frag_data);
2860 st->frag_data = NULL;
2861 }
2862
2863 st->frag_idx++;
2864 st->stepped_offset += skb_frag_size(frag);
2865 }
2866
2867 if (st->frag_data) {
2868 kunmap_atomic(st->frag_data);
2869 st->frag_data = NULL;
2870 }
2871
2872 if (st->root_skb == st->cur_skb && skb_has_frag_list(st->root_skb)) {
2873 st->cur_skb = skb_shinfo(st->root_skb)->frag_list;
2874 st->frag_idx = 0;
2875 goto next_skb;
2876 } else if (st->cur_skb->next) {
2877 st->cur_skb = st->cur_skb->next;
2878 st->frag_idx = 0;
2879 goto next_skb;
2880 }
2881
2882 return 0;
2883}
2884EXPORT_SYMBOL(skb_seq_read);
2885
2886/**
2887 * skb_abort_seq_read - Abort a sequential read of skb data
2888 * @st: state variable
2889 *
2890 * Must be called if skb_seq_read() was not called until it
2891 * returned 0.
2892 */
2893void skb_abort_seq_read(struct skb_seq_state *st)
2894{
2895 if (st->frag_data)
2896 kunmap_atomic(st->frag_data);
2897}
2898EXPORT_SYMBOL(skb_abort_seq_read);
2899
2900#define TS_SKB_CB(state) ((struct skb_seq_state *) &((state)->cb))
2901
2902static unsigned int skb_ts_get_next_block(unsigned int offset, const u8 **text,
2903 struct ts_config *conf,
2904 struct ts_state *state)
2905{
2906 return skb_seq_read(offset, text, TS_SKB_CB(state));
2907}
2908
2909static void skb_ts_finish(struct ts_config *conf, struct ts_state *state)
2910{
2911 skb_abort_seq_read(TS_SKB_CB(state));
2912}
2913
2914/**
2915 * skb_find_text - Find a text pattern in skb data
2916 * @skb: the buffer to look in
2917 * @from: search offset
2918 * @to: search limit
2919 * @config: textsearch configuration
2920 *
2921 * Finds a pattern in the skb data according to the specified
2922 * textsearch configuration. Use textsearch_next() to retrieve
2923 * subsequent occurrences of the pattern. Returns the offset
2924 * to the first occurrence or UINT_MAX if no match was found.
2925 */
2926unsigned int skb_find_text(struct sk_buff *skb, unsigned int from,
2927 unsigned int to, struct ts_config *config)
2928{
2929 struct ts_state state;
2930 unsigned int ret;
2931
2932 config->get_next_block = skb_ts_get_next_block;
2933 config->finish = skb_ts_finish;
2934
2935 skb_prepare_seq_read(skb, from, to, TS_SKB_CB(&state));
2936
2937 ret = textsearch_find(config, &state);
2938 return (ret <= to - from ? ret : UINT_MAX);
2939}
2940EXPORT_SYMBOL(skb_find_text);
2941
2942/**
2943 * skb_append_datato_frags - append the user data to a skb
2944 * @sk: sock structure
2945 * @skb: skb structure to be appended with user data.
2946 * @getfrag: call back function to be used for getting the user data
2947 * @from: pointer to user message iov
2948 * @length: length of the iov message
2949 *
2950 * Description: This procedure append the user data in the fragment part
2951 * of the skb if any page alloc fails user this procedure returns -ENOMEM
2952 */
2953int skb_append_datato_frags(struct sock *sk, struct sk_buff *skb,
2954 int (*getfrag)(void *from, char *to, int offset,
2955 int len, int odd, struct sk_buff *skb),
2956 void *from, int length)
2957{
2958 int frg_cnt = skb_shinfo(skb)->nr_frags;
2959 int copy;
2960 int offset = 0;
2961 int ret;
2962 struct page_frag *pfrag = ¤t->task_frag;
2963
2964 do {
2965 /* Return error if we don't have space for new frag */
2966 if (frg_cnt >= MAX_SKB_FRAGS)
2967 return -EMSGSIZE;
2968
2969 if (!sk_page_frag_refill(sk, pfrag))
2970 return -ENOMEM;
2971
2972 /* copy the user data to page */
2973 copy = min_t(int, length, pfrag->size - pfrag->offset);
2974
2975 ret = getfrag(from, page_address(pfrag->page) + pfrag->offset,
2976 offset, copy, 0, skb);
2977 if (ret < 0)
2978 return -EFAULT;
2979
2980 /* copy was successful so update the size parameters */
2981 skb_fill_page_desc(skb, frg_cnt, pfrag->page, pfrag->offset,
2982 copy);
2983 frg_cnt++;
2984 pfrag->offset += copy;
2985 get_page(pfrag->page);
2986
2987 skb->truesize += copy;
2988 atomic_add(copy, &sk->sk_wmem_alloc);
2989 skb->len += copy;
2990 skb->data_len += copy;
2991 offset += copy;
2992 length -= copy;
2993
2994 } while (length > 0);
2995
2996 return 0;
2997}
2998EXPORT_SYMBOL(skb_append_datato_frags);
2999
3000int skb_append_pagefrags(struct sk_buff *skb, struct page *page,
3001 int offset, size_t size)
3002{
3003 int i = skb_shinfo(skb)->nr_frags;
3004
3005 if (skb_can_coalesce(skb, i, page, offset)) {
3006 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], size);
3007 } else if (i < MAX_SKB_FRAGS) {
3008 get_page(page);
3009 skb_fill_page_desc(skb, i, page, offset, size);
3010 } else {
3011 return -EMSGSIZE;
3012 }
3013
3014 return 0;
3015}
3016EXPORT_SYMBOL_GPL(skb_append_pagefrags);
3017
3018/**
3019 * skb_push_rcsum - push skb and update receive checksum
3020 * @skb: buffer to update
3021 * @len: length of data pulled
3022 *
3023 * This function performs an skb_push on the packet and updates
3024 * the CHECKSUM_COMPLETE checksum. It should be used on
3025 * receive path processing instead of skb_push unless you know
3026 * that the checksum difference is zero (e.g., a valid IP header)
3027 * or you are setting ip_summed to CHECKSUM_NONE.
3028 */
3029static unsigned char *skb_push_rcsum(struct sk_buff *skb, unsigned len)
3030{
3031 skb_push(skb, len);
3032 skb_postpush_rcsum(skb, skb->data, len);
3033 return skb->data;
3034}
3035
3036/**
3037 * skb_pull_rcsum - pull skb and update receive checksum
3038 * @skb: buffer to update
3039 * @len: length of data pulled
3040 *
3041 * This function performs an skb_pull on the packet and updates
3042 * the CHECKSUM_COMPLETE checksum. It should be used on
3043 * receive path processing instead of skb_pull unless you know
3044 * that the checksum difference is zero (e.g., a valid IP header)
3045 * or you are setting ip_summed to CHECKSUM_NONE.
3046 */
3047unsigned char *skb_pull_rcsum(struct sk_buff *skb, unsigned int len)
3048{
3049 unsigned char *data = skb->data;
3050
3051 BUG_ON(len > skb->len);
3052 __skb_pull(skb, len);
3053 skb_postpull_rcsum(skb, data, len);
3054 return skb->data;
3055}
3056EXPORT_SYMBOL_GPL(skb_pull_rcsum);
3057
3058/**
3059 * skb_segment - Perform protocol segmentation on skb.
3060 * @head_skb: buffer to segment
3061 * @features: features for the output path (see dev->features)
3062 *
3063 * This function performs segmentation on the given skb. It returns
3064 * a pointer to the first in a list of new skbs for the segments.
3065 * In case of error it returns ERR_PTR(err).
3066 */
3067struct sk_buff *skb_segment(struct sk_buff *head_skb,
3068 netdev_features_t features)
3069{
3070 struct sk_buff *segs = NULL;
3071 struct sk_buff *tail = NULL;
3072 struct sk_buff *list_skb = skb_shinfo(head_skb)->frag_list;
3073 skb_frag_t *frag = skb_shinfo(head_skb)->frags;
3074 unsigned int mss = skb_shinfo(head_skb)->gso_size;
3075 unsigned int doffset = head_skb->data - skb_mac_header(head_skb);
3076 struct sk_buff *frag_skb = head_skb;
3077 unsigned int offset = doffset;
3078 unsigned int tnl_hlen = skb_tnl_header_len(head_skb);
3079 unsigned int headroom;
3080 unsigned int len;
3081 __be16 proto;
3082 bool csum;
3083 int sg = !!(features & NETIF_F_SG);
3084 int nfrags = skb_shinfo(head_skb)->nr_frags;
3085 int err = -ENOMEM;
3086 int i = 0;
3087 int pos;
3088 int dummy;
3089
3090 __skb_push(head_skb, doffset);
3091 proto = skb_network_protocol(head_skb, &dummy);
3092 if (unlikely(!proto))
3093 return ERR_PTR(-EINVAL);
3094
3095 csum = !!can_checksum_protocol(features, proto);
3096
3097 headroom = skb_headroom(head_skb);
3098 pos = skb_headlen(head_skb);
3099
3100 do {
3101 struct sk_buff *nskb;
3102 skb_frag_t *nskb_frag;
3103 int hsize;
3104 int size;
3105
3106 len = head_skb->len - offset;
3107 if (len > mss)
3108 len = mss;
3109
3110 hsize = skb_headlen(head_skb) - offset;
3111 if (hsize < 0)
3112 hsize = 0;
3113 if (hsize > len || !sg)
3114 hsize = len;
3115
3116 if (!hsize && i >= nfrags && skb_headlen(list_skb) &&
3117 (skb_headlen(list_skb) == len || sg)) {
3118 BUG_ON(skb_headlen(list_skb) > len);
3119
3120 i = 0;
3121 nfrags = skb_shinfo(list_skb)->nr_frags;
3122 frag = skb_shinfo(list_skb)->frags;
3123 frag_skb = list_skb;
3124 pos += skb_headlen(list_skb);
3125
3126 while (pos < offset + len) {
3127 BUG_ON(i >= nfrags);
3128
3129 size = skb_frag_size(frag);
3130 if (pos + size > offset + len)
3131 break;
3132
3133 i++;
3134 pos += size;
3135 frag++;
3136 }
3137
3138 nskb = skb_clone(list_skb, GFP_ATOMIC);
3139 list_skb = list_skb->next;
3140
3141 if (unlikely(!nskb))
3142 goto err;
3143
3144 if (unlikely(pskb_trim(nskb, len))) {
3145 kfree_skb(nskb);
3146 goto err;
3147 }
3148
3149 hsize = skb_end_offset(nskb);
3150 if (skb_cow_head(nskb, doffset + headroom)) {
3151 kfree_skb(nskb);
3152 goto err;
3153 }
3154
3155 nskb->truesize += skb_end_offset(nskb) - hsize;
3156 skb_release_head_state(nskb);
3157 __skb_push(nskb, doffset);
3158 } else {
3159 nskb = __alloc_skb(hsize + doffset + headroom,
3160 GFP_ATOMIC, skb_alloc_rx_flag(head_skb),
3161 NUMA_NO_NODE);
3162
3163 if (unlikely(!nskb))
3164 goto err;
3165
3166 skb_reserve(nskb, headroom);
3167 __skb_put(nskb, doffset);
3168 }
3169
3170 if (segs)
3171 tail->next = nskb;
3172 else
3173 segs = nskb;
3174 tail = nskb;
3175
3176 __copy_skb_header(nskb, head_skb);
3177
3178 skb_headers_offset_update(nskb, skb_headroom(nskb) - headroom);
3179 skb_reset_mac_len(nskb);
3180
3181 skb_copy_from_linear_data_offset(head_skb, -tnl_hlen,
3182 nskb->data - tnl_hlen,
3183 doffset + tnl_hlen);
3184
3185 if (nskb->len == len + doffset)
3186 goto perform_csum_check;
3187
3188 if (!sg) {
3189 if (!nskb->remcsum_offload)
3190 nskb->ip_summed = CHECKSUM_NONE;
3191 SKB_GSO_CB(nskb)->csum =
3192 skb_copy_and_csum_bits(head_skb, offset,
3193 skb_put(nskb, len),
3194 len, 0);
3195 SKB_GSO_CB(nskb)->csum_start =
3196 skb_headroom(nskb) + doffset;
3197 continue;
3198 }
3199
3200 nskb_frag = skb_shinfo(nskb)->frags;
3201
3202 skb_copy_from_linear_data_offset(head_skb, offset,
3203 skb_put(nskb, hsize), hsize);
3204
3205 skb_shinfo(nskb)->tx_flags = skb_shinfo(head_skb)->tx_flags &
3206 SKBTX_SHARED_FRAG;
3207
3208 while (pos < offset + len) {
3209 if (i >= nfrags) {
3210 BUG_ON(skb_headlen(list_skb));
3211
3212 i = 0;
3213 nfrags = skb_shinfo(list_skb)->nr_frags;
3214 frag = skb_shinfo(list_skb)->frags;
3215 frag_skb = list_skb;
3216
3217 BUG_ON(!nfrags);
3218
3219 list_skb = list_skb->next;
3220 }
3221
3222 if (unlikely(skb_shinfo(nskb)->nr_frags >=
3223 MAX_SKB_FRAGS)) {
3224 net_warn_ratelimited(
3225 "skb_segment: too many frags: %u %u\n",
3226 pos, mss);
3227 goto err;
3228 }
3229
3230 if (unlikely(skb_orphan_frags(frag_skb, GFP_ATOMIC)))
3231 goto err;
3232
3233 *nskb_frag = *frag;
3234 __skb_frag_ref(nskb_frag);
3235 size = skb_frag_size(nskb_frag);
3236
3237 if (pos < offset) {
3238 nskb_frag->page_offset += offset - pos;
3239 skb_frag_size_sub(nskb_frag, offset - pos);
3240 }
3241
3242 skb_shinfo(nskb)->nr_frags++;
3243
3244 if (pos + size <= offset + len) {
3245 i++;
3246 frag++;
3247 pos += size;
3248 } else {
3249 skb_frag_size_sub(nskb_frag, pos + size - (offset + len));
3250 goto skip_fraglist;
3251 }
3252
3253 nskb_frag++;
3254 }
3255
3256skip_fraglist:
3257 nskb->data_len = len - hsize;
3258 nskb->len += nskb->data_len;
3259 nskb->truesize += nskb->data_len;
3260
3261perform_csum_check:
3262 if (!csum) {
3263 if (skb_has_shared_frag(nskb)) {
3264 err = __skb_linearize(nskb);
3265 if (err)
3266 goto err;
3267 }
3268 if (!nskb->remcsum_offload)
3269 nskb->ip_summed = CHECKSUM_NONE;
3270 SKB_GSO_CB(nskb)->csum =
3271 skb_checksum(nskb, doffset,
3272 nskb->len - doffset, 0);
3273 SKB_GSO_CB(nskb)->csum_start =
3274 skb_headroom(nskb) + doffset;
3275 }
3276 } while ((offset += len) < head_skb->len);
3277
3278 /* Some callers want to get the end of the list.
3279 * Put it in segs->prev to avoid walking the list.
3280 * (see validate_xmit_skb_list() for example)
3281 */
3282 segs->prev = tail;
3283
3284 /* Following permits correct backpressure, for protocols
3285 * using skb_set_owner_w().
3286 * Idea is to tranfert ownership from head_skb to last segment.
3287 */
3288 if (head_skb->destructor == sock_wfree) {
3289 swap(tail->truesize, head_skb->truesize);
3290 swap(tail->destructor, head_skb->destructor);
3291 swap(tail->sk, head_skb->sk);
3292 }
3293 return segs;
3294
3295err:
3296 kfree_skb_list(segs);
3297 return ERR_PTR(err);
3298}
3299EXPORT_SYMBOL_GPL(skb_segment);
3300
3301int skb_gro_receive(struct sk_buff **head, struct sk_buff *skb)
3302{
3303 struct skb_shared_info *pinfo, *skbinfo = skb_shinfo(skb);
3304 unsigned int offset = skb_gro_offset(skb);
3305 unsigned int headlen = skb_headlen(skb);
3306 unsigned int len = skb_gro_len(skb);
3307 struct sk_buff *lp, *p = *head;
3308 unsigned int delta_truesize;
3309
3310 if (unlikely(p->len + len >= 65536))
3311 return -E2BIG;
3312
3313 lp = NAPI_GRO_CB(p)->last;
3314 pinfo = skb_shinfo(lp);
3315
3316 if (headlen <= offset) {
3317 skb_frag_t *frag;
3318 skb_frag_t *frag2;
3319 int i = skbinfo->nr_frags;
3320 int nr_frags = pinfo->nr_frags + i;
3321
3322 if (nr_frags > MAX_SKB_FRAGS)
3323 goto merge;
3324
3325 offset -= headlen;
3326 pinfo->nr_frags = nr_frags;
3327 skbinfo->nr_frags = 0;
3328
3329 frag = pinfo->frags + nr_frags;
3330 frag2 = skbinfo->frags + i;
3331 do {
3332 *--frag = *--frag2;
3333 } while (--i);
3334
3335 frag->page_offset += offset;
3336 skb_frag_size_sub(frag, offset);
3337
3338 /* all fragments truesize : remove (head size + sk_buff) */
3339 delta_truesize = skb->truesize -
3340 SKB_TRUESIZE(skb_end_offset(skb));
3341
3342 skb->truesize -= skb->data_len;
3343 skb->len -= skb->data_len;
3344 skb->data_len = 0;
3345
3346 NAPI_GRO_CB(skb)->free = NAPI_GRO_FREE;
3347 goto done;
3348 } else if (skb->head_frag) {
3349 int nr_frags = pinfo->nr_frags;
3350 skb_frag_t *frag = pinfo->frags + nr_frags;
3351 struct page *page = virt_to_head_page(skb->head);
3352 unsigned int first_size = headlen - offset;
3353 unsigned int first_offset;
3354
3355 if (nr_frags + 1 + skbinfo->nr_frags > MAX_SKB_FRAGS)
3356 goto merge;
3357
3358 first_offset = skb->data -
3359 (unsigned char *)page_address(page) +
3360 offset;
3361
3362 pinfo->nr_frags = nr_frags + 1 + skbinfo->nr_frags;
3363
3364 frag->page.p = page;
3365 frag->page_offset = first_offset;
3366 skb_frag_size_set(frag, first_size);
3367
3368 memcpy(frag + 1, skbinfo->frags, sizeof(*frag) * skbinfo->nr_frags);
3369 /* We dont need to clear skbinfo->nr_frags here */
3370
3371 delta_truesize = skb->truesize - SKB_DATA_ALIGN(sizeof(struct sk_buff));
3372 NAPI_GRO_CB(skb)->free = NAPI_GRO_FREE_STOLEN_HEAD;
3373 goto done;
3374 }
3375
3376merge:
3377 delta_truesize = skb->truesize;
3378 if (offset > headlen) {
3379 unsigned int eat = offset - headlen;
3380
3381 skbinfo->frags[0].page_offset += eat;
3382 skb_frag_size_sub(&skbinfo->frags[0], eat);
3383 skb->data_len -= eat;
3384 skb->len -= eat;
3385 offset = headlen;
3386 }
3387
3388 __skb_pull(skb, offset);
3389
3390 if (NAPI_GRO_CB(p)->last == p)
3391 skb_shinfo(p)->frag_list = skb;
3392 else
3393 NAPI_GRO_CB(p)->last->next = skb;
3394 NAPI_GRO_CB(p)->last = skb;
3395 __skb_header_release(skb);
3396 lp = p;
3397
3398done:
3399 NAPI_GRO_CB(p)->count++;
3400 p->data_len += len;
3401 p->truesize += delta_truesize;
3402 p->len += len;
3403 if (lp != p) {
3404 lp->data_len += len;
3405 lp->truesize += delta_truesize;
3406 lp->len += len;
3407 }
3408 NAPI_GRO_CB(skb)->same_flow = 1;
3409 return 0;
3410}
3411
3412void __init skb_init(void)
3413{
3414 skbuff_head_cache = kmem_cache_create("skbuff_head_cache",
3415 sizeof(struct sk_buff),
3416 0,
3417 SLAB_HWCACHE_ALIGN|SLAB_PANIC,
3418 NULL);
3419 skbuff_fclone_cache = kmem_cache_create("skbuff_fclone_cache",
3420 sizeof(struct sk_buff_fclones),
3421 0,
3422 SLAB_HWCACHE_ALIGN|SLAB_PANIC,
3423 NULL);
3424}
3425
3426/**
3427 * skb_to_sgvec - Fill a scatter-gather list from a socket buffer
3428 * @skb: Socket buffer containing the buffers to be mapped
3429 * @sg: The scatter-gather list to map into
3430 * @offset: The offset into the buffer's contents to start mapping
3431 * @len: Length of buffer space to be mapped
3432 *
3433 * Fill the specified scatter-gather list with mappings/pointers into a
3434 * region of the buffer space attached to a socket buffer.
3435 */
3436static int
3437__skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int len)
3438{
3439 int start = skb_headlen(skb);
3440 int i, copy = start - offset;
3441 struct sk_buff *frag_iter;
3442 int elt = 0;
3443
3444 if (copy > 0) {
3445 if (copy > len)
3446 copy = len;
3447 sg_set_buf(sg, skb->data + offset, copy);
3448 elt++;
3449 if ((len -= copy) == 0)
3450 return elt;
3451 offset += copy;
3452 }
3453
3454 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
3455 int end;
3456
3457 WARN_ON(start > offset + len);
3458
3459 end = start + skb_frag_size(&skb_shinfo(skb)->frags[i]);
3460 if ((copy = end - offset) > 0) {
3461 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
3462
3463 if (copy > len)
3464 copy = len;
3465 sg_set_page(&sg[elt], skb_frag_page(frag), copy,
3466 frag->page_offset+offset-start);
3467 elt++;
3468 if (!(len -= copy))
3469 return elt;
3470 offset += copy;
3471 }
3472 start = end;
3473 }
3474
3475 skb_walk_frags(skb, frag_iter) {
3476 int end;
3477
3478 WARN_ON(start > offset + len);
3479
3480 end = start + frag_iter->len;
3481 if ((copy = end - offset) > 0) {
3482 if (copy > len)
3483 copy = len;
3484 elt += __skb_to_sgvec(frag_iter, sg+elt, offset - start,
3485 copy);
3486 if ((len -= copy) == 0)
3487 return elt;
3488 offset += copy;
3489 }
3490 start = end;
3491 }
3492 BUG_ON(len);
3493 return elt;
3494}
3495
3496/* As compared with skb_to_sgvec, skb_to_sgvec_nomark only map skb to given
3497 * sglist without mark the sg which contain last skb data as the end.
3498 * So the caller can mannipulate sg list as will when padding new data after
3499 * the first call without calling sg_unmark_end to expend sg list.
3500 *
3501 * Scenario to use skb_to_sgvec_nomark:
3502 * 1. sg_init_table
3503 * 2. skb_to_sgvec_nomark(payload1)
3504 * 3. skb_to_sgvec_nomark(payload2)
3505 *
3506 * This is equivalent to:
3507 * 1. sg_init_table
3508 * 2. skb_to_sgvec(payload1)
3509 * 3. sg_unmark_end
3510 * 4. skb_to_sgvec(payload2)
3511 *
3512 * When mapping mutilple payload conditionally, skb_to_sgvec_nomark
3513 * is more preferable.
3514 */
3515int skb_to_sgvec_nomark(struct sk_buff *skb, struct scatterlist *sg,
3516 int offset, int len)
3517{
3518 return __skb_to_sgvec(skb, sg, offset, len);
3519}
3520EXPORT_SYMBOL_GPL(skb_to_sgvec_nomark);
3521
3522int skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int len)
3523{
3524 int nsg = __skb_to_sgvec(skb, sg, offset, len);
3525
3526 sg_mark_end(&sg[nsg - 1]);
3527
3528 return nsg;
3529}
3530EXPORT_SYMBOL_GPL(skb_to_sgvec);
3531
3532/**
3533 * skb_cow_data - Check that a socket buffer's data buffers are writable
3534 * @skb: The socket buffer to check.
3535 * @tailbits: Amount of trailing space to be added
3536 * @trailer: Returned pointer to the skb where the @tailbits space begins
3537 *
3538 * Make sure that the data buffers attached to a socket buffer are
3539 * writable. If they are not, private copies are made of the data buffers
3540 * and the socket buffer is set to use these instead.
3541 *
3542 * If @tailbits is given, make sure that there is space to write @tailbits
3543 * bytes of data beyond current end of socket buffer. @trailer will be
3544 * set to point to the skb in which this space begins.
3545 *
3546 * The number of scatterlist elements required to completely map the
3547 * COW'd and extended socket buffer will be returned.
3548 */
3549int skb_cow_data(struct sk_buff *skb, int tailbits, struct sk_buff **trailer)
3550{
3551 int copyflag;
3552 int elt;
3553 struct sk_buff *skb1, **skb_p;
3554
3555 /* If skb is cloned or its head is paged, reallocate
3556 * head pulling out all the pages (pages are considered not writable
3557 * at the moment even if they are anonymous).
3558 */
3559 if ((skb_cloned(skb) || skb_shinfo(skb)->nr_frags) &&
3560 __pskb_pull_tail(skb, skb_pagelen(skb)-skb_headlen(skb)) == NULL)
3561 return -ENOMEM;
3562
3563 /* Easy case. Most of packets will go this way. */
3564 if (!skb_has_frag_list(skb)) {
3565 /* A little of trouble, not enough of space for trailer.
3566 * This should not happen, when stack is tuned to generate
3567 * good frames. OK, on miss we reallocate and reserve even more
3568 * space, 128 bytes is fair. */
3569
3570 if (skb_tailroom(skb) < tailbits &&
3571 pskb_expand_head(skb, 0, tailbits-skb_tailroom(skb)+128, GFP_ATOMIC))
3572 return -ENOMEM;
3573
3574 /* Voila! */
3575 *trailer = skb;
3576 return 1;
3577 }
3578
3579 /* Misery. We are in troubles, going to mincer fragments... */
3580
3581 elt = 1;
3582 skb_p = &skb_shinfo(skb)->frag_list;
3583 copyflag = 0;
3584
3585 while ((skb1 = *skb_p) != NULL) {
3586 int ntail = 0;
3587
3588 /* The fragment is partially pulled by someone,
3589 * this can happen on input. Copy it and everything
3590 * after it. */
3591
3592 if (skb_shared(skb1))
3593 copyflag = 1;
3594
3595 /* If the skb is the last, worry about trailer. */
3596
3597 if (skb1->next == NULL && tailbits) {
3598 if (skb_shinfo(skb1)->nr_frags ||
3599 skb_has_frag_list(skb1) ||
3600 skb_tailroom(skb1) < tailbits)
3601 ntail = tailbits + 128;
3602 }
3603
3604 if (copyflag ||
3605 skb_cloned(skb1) ||
3606 ntail ||
3607 skb_shinfo(skb1)->nr_frags ||
3608 skb_has_frag_list(skb1)) {
3609 struct sk_buff *skb2;
3610
3611 /* Fuck, we are miserable poor guys... */
3612 if (ntail == 0)
3613 skb2 = skb_copy(skb1, GFP_ATOMIC);
3614 else
3615 skb2 = skb_copy_expand(skb1,
3616 skb_headroom(skb1),
3617 ntail,
3618 GFP_ATOMIC);
3619 if (unlikely(skb2 == NULL))
3620 return -ENOMEM;
3621
3622 if (skb1->sk)
3623 skb_set_owner_w(skb2, skb1->sk);
3624
3625 /* Looking around. Are we still alive?
3626 * OK, link new skb, drop old one */
3627
3628 skb2->next = skb1->next;
3629 *skb_p = skb2;
3630 kfree_skb(skb1);
3631 skb1 = skb2;
3632 }
3633 elt++;
3634 *trailer = skb1;
3635 skb_p = &skb1->next;
3636 }
3637
3638 return elt;
3639}
3640EXPORT_SYMBOL_GPL(skb_cow_data);
3641
3642static void sock_rmem_free(struct sk_buff *skb)
3643{
3644 struct sock *sk = skb->sk;
3645
3646 atomic_sub(skb->truesize, &sk->sk_rmem_alloc);
3647}
3648
3649/*
3650 * Note: We dont mem charge error packets (no sk_forward_alloc changes)
3651 */
3652int sock_queue_err_skb(struct sock *sk, struct sk_buff *skb)
3653{
3654 if (atomic_read(&sk->sk_rmem_alloc) + skb->truesize >=
3655 (unsigned int)sk->sk_rcvbuf)
3656 return -ENOMEM;
3657
3658 skb_orphan(skb);
3659 skb->sk = sk;
3660 skb->destructor = sock_rmem_free;
3661 atomic_add(skb->truesize, &sk->sk_rmem_alloc);
3662
3663 /* before exiting rcu section, make sure dst is refcounted */
3664 skb_dst_force(skb);
3665
3666 skb_queue_tail(&sk->sk_error_queue, skb);
3667 if (!sock_flag(sk, SOCK_DEAD))
3668 sk->sk_data_ready(sk);
3669 return 0;
3670}
3671EXPORT_SYMBOL(sock_queue_err_skb);
3672
3673struct sk_buff *sock_dequeue_err_skb(struct sock *sk)
3674{
3675 struct sk_buff_head *q = &sk->sk_error_queue;
3676 struct sk_buff *skb, *skb_next;
3677 unsigned long flags;
3678 int err = 0;
3679
3680 spin_lock_irqsave(&q->lock, flags);
3681 skb = __skb_dequeue(q);
3682 if (skb && (skb_next = skb_peek(q)))
3683 err = SKB_EXT_ERR(skb_next)->ee.ee_errno;
3684 spin_unlock_irqrestore(&q->lock, flags);
3685
3686 sk->sk_err = err;
3687 if (err)
3688 sk->sk_error_report(sk);
3689
3690 return skb;
3691}
3692EXPORT_SYMBOL(sock_dequeue_err_skb);
3693
3694/**
3695 * skb_clone_sk - create clone of skb, and take reference to socket
3696 * @skb: the skb to clone
3697 *
3698 * This function creates a clone of a buffer that holds a reference on
3699 * sk_refcnt. Buffers created via this function are meant to be
3700 * returned using sock_queue_err_skb, or free via kfree_skb.
3701 *
3702 * When passing buffers allocated with this function to sock_queue_err_skb
3703 * it is necessary to wrap the call with sock_hold/sock_put in order to
3704 * prevent the socket from being released prior to being enqueued on
3705 * the sk_error_queue.
3706 */
3707struct sk_buff *skb_clone_sk(struct sk_buff *skb)
3708{
3709 struct sock *sk = skb->sk;
3710 struct sk_buff *clone;
3711
3712 if (!sk || !atomic_inc_not_zero(&sk->sk_refcnt))
3713 return NULL;
3714
3715 clone = skb_clone(skb, GFP_ATOMIC);
3716 if (!clone) {
3717 sock_put(sk);
3718 return NULL;
3719 }
3720
3721 clone->sk = sk;
3722 clone->destructor = sock_efree;
3723
3724 return clone;
3725}
3726EXPORT_SYMBOL(skb_clone_sk);
3727
3728static void __skb_complete_tx_timestamp(struct sk_buff *skb,
3729 struct sock *sk,
3730 int tstype)
3731{
3732 struct sock_exterr_skb *serr;
3733 int err;
3734
3735 serr = SKB_EXT_ERR(skb);
3736 memset(serr, 0, sizeof(*serr));
3737 serr->ee.ee_errno = ENOMSG;
3738 serr->ee.ee_origin = SO_EE_ORIGIN_TIMESTAMPING;
3739 serr->ee.ee_info = tstype;
3740 if (sk->sk_tsflags & SOF_TIMESTAMPING_OPT_ID) {
3741 serr->ee.ee_data = skb_shinfo(skb)->tskey;
3742 if (sk->sk_protocol == IPPROTO_TCP &&
3743 sk->sk_type == SOCK_STREAM)
3744 serr->ee.ee_data -= sk->sk_tskey;
3745 }
3746
3747 err = sock_queue_err_skb(sk, skb);
3748
3749 if (err)
3750 kfree_skb(skb);
3751}
3752
3753static bool skb_may_tx_timestamp(struct sock *sk, bool tsonly)
3754{
3755 bool ret;
3756
3757 if (likely(sysctl_tstamp_allow_data || tsonly))
3758 return true;
3759
3760 read_lock_bh(&sk->sk_callback_lock);
3761 ret = sk->sk_socket && sk->sk_socket->file &&
3762 file_ns_capable(sk->sk_socket->file, &init_user_ns, CAP_NET_RAW);
3763 read_unlock_bh(&sk->sk_callback_lock);
3764 return ret;
3765}
3766
3767void skb_complete_tx_timestamp(struct sk_buff *skb,
3768 struct skb_shared_hwtstamps *hwtstamps)
3769{
3770 struct sock *sk = skb->sk;
3771
3772 if (!skb_may_tx_timestamp(sk, false))
3773 return;
3774
3775 /* take a reference to prevent skb_orphan() from freeing the socket */
3776 sock_hold(sk);
3777
3778 *skb_hwtstamps(skb) = *hwtstamps;
3779 __skb_complete_tx_timestamp(skb, sk, SCM_TSTAMP_SND);
3780
3781 sock_put(sk);
3782}
3783EXPORT_SYMBOL_GPL(skb_complete_tx_timestamp);
3784
3785void __skb_tstamp_tx(struct sk_buff *orig_skb,
3786 struct skb_shared_hwtstamps *hwtstamps,
3787 struct sock *sk, int tstype)
3788{
3789 struct sk_buff *skb;
3790 bool tsonly;
3791
3792 if (!sk)
3793 return;
3794
3795 tsonly = sk->sk_tsflags & SOF_TIMESTAMPING_OPT_TSONLY;
3796 if (!skb_may_tx_timestamp(sk, tsonly))
3797 return;
3798
3799 if (tsonly)
3800 skb = alloc_skb(0, GFP_ATOMIC);
3801 else
3802 skb = skb_clone(orig_skb, GFP_ATOMIC);
3803 if (!skb)
3804 return;
3805
3806 if (tsonly) {
3807 skb_shinfo(skb)->tx_flags = skb_shinfo(orig_skb)->tx_flags;
3808 skb_shinfo(skb)->tskey = skb_shinfo(orig_skb)->tskey;
3809 }
3810
3811 if (hwtstamps)
3812 *skb_hwtstamps(skb) = *hwtstamps;
3813 else
3814 skb->tstamp = ktime_get_real();
3815
3816 __skb_complete_tx_timestamp(skb, sk, tstype);
3817}
3818EXPORT_SYMBOL_GPL(__skb_tstamp_tx);
3819
3820void skb_tstamp_tx(struct sk_buff *orig_skb,
3821 struct skb_shared_hwtstamps *hwtstamps)
3822{
3823 return __skb_tstamp_tx(orig_skb, hwtstamps, orig_skb->sk,
3824 SCM_TSTAMP_SND);
3825}
3826EXPORT_SYMBOL_GPL(skb_tstamp_tx);
3827
3828void skb_complete_wifi_ack(struct sk_buff *skb, bool acked)
3829{
3830 struct sock *sk = skb->sk;
3831 struct sock_exterr_skb *serr;
3832 int err;
3833
3834 skb->wifi_acked_valid = 1;
3835 skb->wifi_acked = acked;
3836
3837 serr = SKB_EXT_ERR(skb);
3838 memset(serr, 0, sizeof(*serr));
3839 serr->ee.ee_errno = ENOMSG;
3840 serr->ee.ee_origin = SO_EE_ORIGIN_TXSTATUS;
3841
3842 /* take a reference to prevent skb_orphan() from freeing the socket */
3843 sock_hold(sk);
3844
3845 err = sock_queue_err_skb(sk, skb);
3846 if (err)
3847 kfree_skb(skb);
3848
3849 sock_put(sk);
3850}
3851EXPORT_SYMBOL_GPL(skb_complete_wifi_ack);
3852
3853/**
3854 * skb_partial_csum_set - set up and verify partial csum values for packet
3855 * @skb: the skb to set
3856 * @start: the number of bytes after skb->data to start checksumming.
3857 * @off: the offset from start to place the checksum.
3858 *
3859 * For untrusted partially-checksummed packets, we need to make sure the values
3860 * for skb->csum_start and skb->csum_offset are valid so we don't oops.
3861 *
3862 * This function checks and sets those values and skb->ip_summed: if this
3863 * returns false you should drop the packet.
3864 */
3865bool skb_partial_csum_set(struct sk_buff *skb, u16 start, u16 off)
3866{
3867 if (unlikely(start > skb_headlen(skb)) ||
3868 unlikely((int)start + off > skb_headlen(skb) - 2)) {
3869 net_warn_ratelimited("bad partial csum: csum=%u/%u len=%u\n",
3870 start, off, skb_headlen(skb));
3871 return false;
3872 }
3873 skb->ip_summed = CHECKSUM_PARTIAL;
3874 skb->csum_start = skb_headroom(skb) + start;
3875 skb->csum_offset = off;
3876 skb_set_transport_header(skb, start);
3877 return true;
3878}
3879EXPORT_SYMBOL_GPL(skb_partial_csum_set);
3880
3881static int skb_maybe_pull_tail(struct sk_buff *skb, unsigned int len,
3882 unsigned int max)
3883{
3884 if (skb_headlen(skb) >= len)
3885 return 0;
3886
3887 /* If we need to pullup then pullup to the max, so we
3888 * won't need to do it again.
3889 */
3890 if (max > skb->len)
3891 max = skb->len;
3892
3893 if (__pskb_pull_tail(skb, max - skb_headlen(skb)) == NULL)
3894 return -ENOMEM;
3895
3896 if (skb_headlen(skb) < len)
3897 return -EPROTO;
3898
3899 return 0;
3900}
3901
3902#define MAX_TCP_HDR_LEN (15 * 4)
3903
3904static __sum16 *skb_checksum_setup_ip(struct sk_buff *skb,
3905 typeof(IPPROTO_IP) proto,
3906 unsigned int off)
3907{
3908 switch (proto) {
3909 int err;
3910
3911 case IPPROTO_TCP:
3912 err = skb_maybe_pull_tail(skb, off + sizeof(struct tcphdr),
3913 off + MAX_TCP_HDR_LEN);
3914 if (!err && !skb_partial_csum_set(skb, off,
3915 offsetof(struct tcphdr,
3916 check)))
3917 err = -EPROTO;
3918 return err ? ERR_PTR(err) : &tcp_hdr(skb)->check;
3919
3920 case IPPROTO_UDP:
3921 err = skb_maybe_pull_tail(skb, off + sizeof(struct udphdr),
3922 off + sizeof(struct udphdr));
3923 if (!err && !skb_partial_csum_set(skb, off,
3924 offsetof(struct udphdr,
3925 check)))
3926 err = -EPROTO;
3927 return err ? ERR_PTR(err) : &udp_hdr(skb)->check;
3928 }
3929
3930 return ERR_PTR(-EPROTO);
3931}
3932
3933/* This value should be large enough to cover a tagged ethernet header plus
3934 * maximally sized IP and TCP or UDP headers.
3935 */
3936#define MAX_IP_HDR_LEN 128
3937
3938static int skb_checksum_setup_ipv4(struct sk_buff *skb, bool recalculate)
3939{
3940 unsigned int off;
3941 bool fragment;
3942 __sum16 *csum;
3943 int err;
3944
3945 fragment = false;
3946
3947 err = skb_maybe_pull_tail(skb,
3948 sizeof(struct iphdr),
3949 MAX_IP_HDR_LEN);
3950 if (err < 0)
3951 goto out;
3952
3953 if (ip_hdr(skb)->frag_off & htons(IP_OFFSET | IP_MF))
3954 fragment = true;
3955
3956 off = ip_hdrlen(skb);
3957
3958 err = -EPROTO;
3959
3960 if (fragment)
3961 goto out;
3962
3963 csum = skb_checksum_setup_ip(skb, ip_hdr(skb)->protocol, off);
3964 if (IS_ERR(csum))
3965 return PTR_ERR(csum);
3966
3967 if (recalculate)
3968 *csum = ~csum_tcpudp_magic(ip_hdr(skb)->saddr,
3969 ip_hdr(skb)->daddr,
3970 skb->len - off,
3971 ip_hdr(skb)->protocol, 0);
3972 err = 0;
3973
3974out:
3975 return err;
3976}
3977
3978/* This value should be large enough to cover a tagged ethernet header plus
3979 * an IPv6 header, all options, and a maximal TCP or UDP header.
3980 */
3981#define MAX_IPV6_HDR_LEN 256
3982
3983#define OPT_HDR(type, skb, off) \
3984 (type *)(skb_network_header(skb) + (off))
3985
3986static int skb_checksum_setup_ipv6(struct sk_buff *skb, bool recalculate)
3987{
3988 int err;
3989 u8 nexthdr;
3990 unsigned int off;
3991 unsigned int len;
3992 bool fragment;
3993 bool done;
3994 __sum16 *csum;
3995
3996 fragment = false;
3997 done = false;
3998
3999 off = sizeof(struct ipv6hdr);
4000
4001 err = skb_maybe_pull_tail(skb, off, MAX_IPV6_HDR_LEN);
4002 if (err < 0)
4003 goto out;
4004
4005 nexthdr = ipv6_hdr(skb)->nexthdr;
4006
4007 len = sizeof(struct ipv6hdr) + ntohs(ipv6_hdr(skb)->payload_len);
4008 while (off <= len && !done) {
4009 switch (nexthdr) {
4010 case IPPROTO_DSTOPTS:
4011 case IPPROTO_HOPOPTS:
4012 case IPPROTO_ROUTING: {
4013 struct ipv6_opt_hdr *hp;
4014
4015 err = skb_maybe_pull_tail(skb,
4016 off +
4017 sizeof(struct ipv6_opt_hdr),
4018 MAX_IPV6_HDR_LEN);
4019 if (err < 0)
4020 goto out;
4021
4022 hp = OPT_HDR(struct ipv6_opt_hdr, skb, off);
4023 nexthdr = hp->nexthdr;
4024 off += ipv6_optlen(hp);
4025 break;
4026 }
4027 case IPPROTO_AH: {
4028 struct ip_auth_hdr *hp;
4029
4030 err = skb_maybe_pull_tail(skb,
4031 off +
4032 sizeof(struct ip_auth_hdr),
4033 MAX_IPV6_HDR_LEN);
4034 if (err < 0)
4035 goto out;
4036
4037 hp = OPT_HDR(struct ip_auth_hdr, skb, off);
4038 nexthdr = hp->nexthdr;
4039 off += ipv6_authlen(hp);
4040 break;
4041 }
4042 case IPPROTO_FRAGMENT: {
4043 struct frag_hdr *hp;
4044
4045 err = skb_maybe_pull_tail(skb,
4046 off +
4047 sizeof(struct frag_hdr),
4048 MAX_IPV6_HDR_LEN);
4049 if (err < 0)
4050 goto out;
4051
4052 hp = OPT_HDR(struct frag_hdr, skb, off);
4053
4054 if (hp->frag_off & htons(IP6_OFFSET | IP6_MF))
4055 fragment = true;
4056
4057 nexthdr = hp->nexthdr;
4058 off += sizeof(struct frag_hdr);
4059 break;
4060 }
4061 default:
4062 done = true;
4063 break;
4064 }
4065 }
4066
4067 err = -EPROTO;
4068
4069 if (!done || fragment)
4070 goto out;
4071
4072 csum = skb_checksum_setup_ip(skb, nexthdr, off);
4073 if (IS_ERR(csum))
4074 return PTR_ERR(csum);
4075
4076 if (recalculate)
4077 *csum = ~csum_ipv6_magic(&ipv6_hdr(skb)->saddr,
4078 &ipv6_hdr(skb)->daddr,
4079 skb->len - off, nexthdr, 0);
4080 err = 0;
4081
4082out:
4083 return err;
4084}
4085
4086/**
4087 * skb_checksum_setup - set up partial checksum offset
4088 * @skb: the skb to set up
4089 * @recalculate: if true the pseudo-header checksum will be recalculated
4090 */
4091int skb_checksum_setup(struct sk_buff *skb, bool recalculate)
4092{
4093 int err;
4094
4095 switch (skb->protocol) {
4096 case htons(ETH_P_IP):
4097 err = skb_checksum_setup_ipv4(skb, recalculate);
4098 break;
4099
4100 case htons(ETH_P_IPV6):
4101 err = skb_checksum_setup_ipv6(skb, recalculate);
4102 break;
4103
4104 default:
4105 err = -EPROTO;
4106 break;
4107 }
4108
4109 return err;
4110}
4111EXPORT_SYMBOL(skb_checksum_setup);
4112
4113/**
4114 * skb_checksum_maybe_trim - maybe trims the given skb
4115 * @skb: the skb to check
4116 * @transport_len: the data length beyond the network header
4117 *
4118 * Checks whether the given skb has data beyond the given transport length.
4119 * If so, returns a cloned skb trimmed to this transport length.
4120 * Otherwise returns the provided skb. Returns NULL in error cases
4121 * (e.g. transport_len exceeds skb length or out-of-memory).
4122 *
4123 * Caller needs to set the skb transport header and free any returned skb if it
4124 * differs from the provided skb.
4125 */
4126static struct sk_buff *skb_checksum_maybe_trim(struct sk_buff *skb,
4127 unsigned int transport_len)
4128{
4129 struct sk_buff *skb_chk;
4130 unsigned int len = skb_transport_offset(skb) + transport_len;
4131 int ret;
4132
4133 if (skb->len < len)
4134 return NULL;
4135 else if (skb->len == len)
4136 return skb;
4137
4138 skb_chk = skb_clone(skb, GFP_ATOMIC);
4139 if (!skb_chk)
4140 return NULL;
4141
4142 ret = pskb_trim_rcsum(skb_chk, len);
4143 if (ret) {
4144 kfree_skb(skb_chk);
4145 return NULL;
4146 }
4147
4148 return skb_chk;
4149}
4150
4151/**
4152 * skb_checksum_trimmed - validate checksum of an skb
4153 * @skb: the skb to check
4154 * @transport_len: the data length beyond the network header
4155 * @skb_chkf: checksum function to use
4156 *
4157 * Applies the given checksum function skb_chkf to the provided skb.
4158 * Returns a checked and maybe trimmed skb. Returns NULL on error.
4159 *
4160 * If the skb has data beyond the given transport length, then a
4161 * trimmed & cloned skb is checked and returned.
4162 *
4163 * Caller needs to set the skb transport header and free any returned skb if it
4164 * differs from the provided skb.
4165 */
4166struct sk_buff *skb_checksum_trimmed(struct sk_buff *skb,
4167 unsigned int transport_len,
4168 __sum16(*skb_chkf)(struct sk_buff *skb))
4169{
4170 struct sk_buff *skb_chk;
4171 unsigned int offset = skb_transport_offset(skb);
4172 __sum16 ret;
4173
4174 skb_chk = skb_checksum_maybe_trim(skb, transport_len);
4175 if (!skb_chk)
4176 goto err;
4177
4178 if (!pskb_may_pull(skb_chk, offset))
4179 goto err;
4180
4181 skb_pull_rcsum(skb_chk, offset);
4182 ret = skb_chkf(skb_chk);
4183 skb_push_rcsum(skb_chk, offset);
4184
4185 if (ret)
4186 goto err;
4187
4188 return skb_chk;
4189
4190err:
4191 if (skb_chk && skb_chk != skb)
4192 kfree_skb(skb_chk);
4193
4194 return NULL;
4195
4196}
4197EXPORT_SYMBOL(skb_checksum_trimmed);
4198
4199void __skb_warn_lro_forwarding(const struct sk_buff *skb)
4200{
4201 net_warn_ratelimited("%s: received packets cannot be forwarded while LRO is enabled\n",
4202 skb->dev->name);
4203}
4204EXPORT_SYMBOL(__skb_warn_lro_forwarding);
4205
4206void kfree_skb_partial(struct sk_buff *skb, bool head_stolen)
4207{
4208 if (head_stolen) {
4209 skb_release_head_state(skb);
4210 kmem_cache_free(skbuff_head_cache, skb);
4211 } else {
4212 __kfree_skb(skb);
4213 }
4214}
4215EXPORT_SYMBOL(kfree_skb_partial);
4216
4217/**
4218 * skb_try_coalesce - try to merge skb to prior one
4219 * @to: prior buffer
4220 * @from: buffer to add
4221 * @fragstolen: pointer to boolean
4222 * @delta_truesize: how much more was allocated than was requested
4223 */
4224bool skb_try_coalesce(struct sk_buff *to, struct sk_buff *from,
4225 bool *fragstolen, int *delta_truesize)
4226{
4227 int i, delta, len = from->len;
4228
4229 *fragstolen = false;
4230
4231 if (skb_cloned(to))
4232 return false;
4233
4234 if (len <= skb_tailroom(to)) {
4235 if (len)
4236 BUG_ON(skb_copy_bits(from, 0, skb_put(to, len), len));
4237 *delta_truesize = 0;
4238 return true;
4239 }
4240
4241 if (skb_has_frag_list(to) || skb_has_frag_list(from))
4242 return false;
4243
4244 if (skb_headlen(from) != 0) {
4245 struct page *page;
4246 unsigned int offset;
4247
4248 if (skb_shinfo(to)->nr_frags +
4249 skb_shinfo(from)->nr_frags >= MAX_SKB_FRAGS)
4250 return false;
4251
4252 if (skb_head_is_locked(from))
4253 return false;
4254
4255 delta = from->truesize - SKB_DATA_ALIGN(sizeof(struct sk_buff));
4256
4257 page = virt_to_head_page(from->head);
4258 offset = from->data - (unsigned char *)page_address(page);
4259
4260 skb_fill_page_desc(to, skb_shinfo(to)->nr_frags,
4261 page, offset, skb_headlen(from));
4262 *fragstolen = true;
4263 } else {
4264 if (skb_shinfo(to)->nr_frags +
4265 skb_shinfo(from)->nr_frags > MAX_SKB_FRAGS)
4266 return false;
4267
4268 delta = from->truesize - SKB_TRUESIZE(skb_end_offset(from));
4269 }
4270
4271 WARN_ON_ONCE(delta < len);
4272
4273 memcpy(skb_shinfo(to)->frags + skb_shinfo(to)->nr_frags,
4274 skb_shinfo(from)->frags,
4275 skb_shinfo(from)->nr_frags * sizeof(skb_frag_t));
4276 skb_shinfo(to)->nr_frags += skb_shinfo(from)->nr_frags;
4277
4278 if (!skb_cloned(from))
4279 skb_shinfo(from)->nr_frags = 0;
4280
4281 /* if the skb is not cloned this does nothing
4282 * since we set nr_frags to 0.
4283 */
4284 for (i = 0; i < skb_shinfo(from)->nr_frags; i++)
4285 skb_frag_ref(from, i);
4286
4287 to->truesize += delta;
4288 to->len += len;
4289 to->data_len += len;
4290
4291 *delta_truesize = delta;
4292 return true;
4293}
4294EXPORT_SYMBOL(skb_try_coalesce);
4295
4296/**
4297 * skb_scrub_packet - scrub an skb
4298 *
4299 * @skb: buffer to clean
4300 * @xnet: packet is crossing netns
4301 *
4302 * skb_scrub_packet can be used after encapsulating or decapsulting a packet
4303 * into/from a tunnel. Some information have to be cleared during these
4304 * operations.
4305 * skb_scrub_packet can also be used to clean a skb before injecting it in
4306 * another namespace (@xnet == true). We have to clear all information in the
4307 * skb that could impact namespace isolation.
4308 */
4309void skb_scrub_packet(struct sk_buff *skb, bool xnet)
4310{
4311 skb->tstamp.tv64 = 0;
4312 skb->pkt_type = PACKET_HOST;
4313 skb->skb_iif = 0;
4314 skb->ignore_df = 0;
4315 skb_dst_drop(skb);
4316 secpath_reset(skb);
4317 nf_reset(skb);
4318 nf_reset_trace(skb);
4319
4320 if (!xnet)
4321 return;
4322
4323 skb_orphan(skb);
4324 skb->mark = 0;
4325}
4326EXPORT_SYMBOL_GPL(skb_scrub_packet);
4327
4328/**
4329 * skb_gso_transport_seglen - Return length of individual segments of a gso packet
4330 *
4331 * @skb: GSO skb
4332 *
4333 * skb_gso_transport_seglen is used to determine the real size of the
4334 * individual segments, including Layer4 headers (TCP/UDP).
4335 *
4336 * The MAC/L2 or network (IP, IPv6) headers are not accounted for.
4337 */
4338unsigned int skb_gso_transport_seglen(const struct sk_buff *skb)
4339{
4340 const struct skb_shared_info *shinfo = skb_shinfo(skb);
4341 unsigned int thlen = 0;
4342
4343 if (skb->encapsulation) {
4344 thlen = skb_inner_transport_header(skb) -
4345 skb_transport_header(skb);
4346
4347 if (likely(shinfo->gso_type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6)))
4348 thlen += inner_tcp_hdrlen(skb);
4349 } else if (likely(shinfo->gso_type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6))) {
4350 thlen = tcp_hdrlen(skb);
4351 }
4352 /* UFO sets gso_size to the size of the fragmentation
4353 * payload, i.e. the size of the L4 (UDP) header is already
4354 * accounted for.
4355 */
4356 return thlen + shinfo->gso_size;
4357}
4358EXPORT_SYMBOL_GPL(skb_gso_transport_seglen);
4359
4360static struct sk_buff *skb_reorder_vlan_header(struct sk_buff *skb)
4361{
4362 if (skb_cow(skb, skb_headroom(skb)) < 0) {
4363 kfree_skb(skb);
4364 return NULL;
4365 }
4366
4367 memmove(skb->data - ETH_HLEN, skb->data - skb->mac_len - VLAN_HLEN,
4368 2 * ETH_ALEN);
4369 skb->mac_header += VLAN_HLEN;
4370 return skb;
4371}
4372
4373struct sk_buff *skb_vlan_untag(struct sk_buff *skb)
4374{
4375 struct vlan_hdr *vhdr;
4376 u16 vlan_tci;
4377
4378 if (unlikely(skb_vlan_tag_present(skb))) {
4379 /* vlan_tci is already set-up so leave this for another time */
4380 return skb;
4381 }
4382
4383 skb = skb_share_check(skb, GFP_ATOMIC);
4384 if (unlikely(!skb))
4385 goto err_free;
4386
4387 if (unlikely(!pskb_may_pull(skb, VLAN_HLEN)))
4388 goto err_free;
4389
4390 vhdr = (struct vlan_hdr *)skb->data;
4391 vlan_tci = ntohs(vhdr->h_vlan_TCI);
4392 __vlan_hwaccel_put_tag(skb, skb->protocol, vlan_tci);
4393
4394 skb_pull_rcsum(skb, VLAN_HLEN);
4395 vlan_set_encap_proto(skb, vhdr);
4396
4397 skb = skb_reorder_vlan_header(skb);
4398 if (unlikely(!skb))
4399 goto err_free;
4400
4401 skb_reset_network_header(skb);
4402 skb_reset_transport_header(skb);
4403 skb_reset_mac_len(skb);
4404
4405 return skb;
4406
4407err_free:
4408 kfree_skb(skb);
4409 return NULL;
4410}
4411EXPORT_SYMBOL(skb_vlan_untag);
4412
4413int skb_ensure_writable(struct sk_buff *skb, int write_len)
4414{
4415 if (!pskb_may_pull(skb, write_len))
4416 return -ENOMEM;
4417
4418 if (!skb_cloned(skb) || skb_clone_writable(skb, write_len))
4419 return 0;
4420
4421 return pskb_expand_head(skb, 0, 0, GFP_ATOMIC);
4422}
4423EXPORT_SYMBOL(skb_ensure_writable);
4424
4425/* remove VLAN header from packet and update csum accordingly. */
4426static int __skb_vlan_pop(struct sk_buff *skb, u16 *vlan_tci)
4427{
4428 struct vlan_hdr *vhdr;
4429 unsigned int offset = skb->data - skb_mac_header(skb);
4430 int err;
4431
4432 __skb_push(skb, offset);
4433 err = skb_ensure_writable(skb, VLAN_ETH_HLEN);
4434 if (unlikely(err))
4435 goto pull;
4436
4437 skb_postpull_rcsum(skb, skb->data + (2 * ETH_ALEN), VLAN_HLEN);
4438
4439 vhdr = (struct vlan_hdr *)(skb->data + ETH_HLEN);
4440 *vlan_tci = ntohs(vhdr->h_vlan_TCI);
4441
4442 memmove(skb->data + VLAN_HLEN, skb->data, 2 * ETH_ALEN);
4443 __skb_pull(skb, VLAN_HLEN);
4444
4445 vlan_set_encap_proto(skb, vhdr);
4446 skb->mac_header += VLAN_HLEN;
4447
4448 if (skb_network_offset(skb) < ETH_HLEN)
4449 skb_set_network_header(skb, ETH_HLEN);
4450
4451 skb_reset_mac_len(skb);
4452pull:
4453 __skb_pull(skb, offset);
4454
4455 return err;
4456}
4457
4458int skb_vlan_pop(struct sk_buff *skb)
4459{
4460 u16 vlan_tci;
4461 __be16 vlan_proto;
4462 int err;
4463
4464 if (likely(skb_vlan_tag_present(skb))) {
4465 skb->vlan_tci = 0;
4466 } else {
4467 if (unlikely((skb->protocol != htons(ETH_P_8021Q) &&
4468 skb->protocol != htons(ETH_P_8021AD)) ||
4469 skb->len < VLAN_ETH_HLEN))
4470 return 0;
4471
4472 err = __skb_vlan_pop(skb, &vlan_tci);
4473 if (err)
4474 return err;
4475 }
4476 /* move next vlan tag to hw accel tag */
4477 if (likely((skb->protocol != htons(ETH_P_8021Q) &&
4478 skb->protocol != htons(ETH_P_8021AD)) ||
4479 skb->len < VLAN_ETH_HLEN))
4480 return 0;
4481
4482 vlan_proto = skb->protocol;
4483 err = __skb_vlan_pop(skb, &vlan_tci);
4484 if (unlikely(err))
4485 return err;
4486
4487 __vlan_hwaccel_put_tag(skb, vlan_proto, vlan_tci);
4488 return 0;
4489}
4490EXPORT_SYMBOL(skb_vlan_pop);
4491
4492int skb_vlan_push(struct sk_buff *skb, __be16 vlan_proto, u16 vlan_tci)
4493{
4494 if (skb_vlan_tag_present(skb)) {
4495 unsigned int offset = skb->data - skb_mac_header(skb);
4496 int err;
4497
4498 /* __vlan_insert_tag expect skb->data pointing to mac header.
4499 * So change skb->data before calling it and change back to
4500 * original position later
4501 */
4502 __skb_push(skb, offset);
4503 err = __vlan_insert_tag(skb, skb->vlan_proto,
4504 skb_vlan_tag_get(skb));
4505 if (err) {
4506 __skb_pull(skb, offset);
4507 return err;
4508 }
4509
4510 skb->protocol = skb->vlan_proto;
4511 skb->mac_len += VLAN_HLEN;
4512
4513 skb_postpush_rcsum(skb, skb->data + (2 * ETH_ALEN), VLAN_HLEN);
4514 __skb_pull(skb, offset);
4515 }
4516 __vlan_hwaccel_put_tag(skb, vlan_proto, vlan_tci);
4517 return 0;
4518}
4519EXPORT_SYMBOL(skb_vlan_push);
4520
4521/**
4522 * alloc_skb_with_frags - allocate skb with page frags
4523 *
4524 * @header_len: size of linear part
4525 * @data_len: needed length in frags
4526 * @max_page_order: max page order desired.
4527 * @errcode: pointer to error code if any
4528 * @gfp_mask: allocation mask
4529 *
4530 * This can be used to allocate a paged skb, given a maximal order for frags.
4531 */
4532struct sk_buff *alloc_skb_with_frags(unsigned long header_len,
4533 unsigned long data_len,
4534 int max_page_order,
4535 int *errcode,
4536 gfp_t gfp_mask)
4537{
4538 int npages = (data_len + (PAGE_SIZE - 1)) >> PAGE_SHIFT;
4539 unsigned long chunk;
4540 struct sk_buff *skb;
4541 struct page *page;
4542 gfp_t gfp_head;
4543 int i;
4544
4545 *errcode = -EMSGSIZE;
4546 /* Note this test could be relaxed, if we succeed to allocate
4547 * high order pages...
4548 */
4549 if (npages > MAX_SKB_FRAGS)
4550 return NULL;
4551
4552 gfp_head = gfp_mask;
4553 if (gfp_head & __GFP_DIRECT_RECLAIM)
4554 gfp_head |= __GFP_REPEAT;
4555
4556 *errcode = -ENOBUFS;
4557 skb = alloc_skb(header_len, gfp_head);
4558 if (!skb)
4559 return NULL;
4560
4561 skb->truesize += npages << PAGE_SHIFT;
4562
4563 for (i = 0; npages > 0; i++) {
4564 int order = max_page_order;
4565
4566 while (order) {
4567 if (npages >= 1 << order) {
4568 page = alloc_pages((gfp_mask & ~__GFP_DIRECT_RECLAIM) |
4569 __GFP_COMP |
4570 __GFP_NOWARN |
4571 __GFP_NORETRY,
4572 order);
4573 if (page)
4574 goto fill_page;
4575 /* Do not retry other high order allocations */
4576 order = 1;
4577 max_page_order = 0;
4578 }
4579 order--;
4580 }
4581 page = alloc_page(gfp_mask);
4582 if (!page)
4583 goto failure;
4584fill_page:
4585 chunk = min_t(unsigned long, data_len,
4586 PAGE_SIZE << order);
4587 skb_fill_page_desc(skb, i, page, 0, chunk);
4588 data_len -= chunk;
4589 npages -= 1 << order;
4590 }
4591 return skb;
4592
4593failure:
4594 kfree_skb(skb);
4595 return NULL;
4596}
4597EXPORT_SYMBOL(alloc_skb_with_frags);
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Routines having to do with the 'struct sk_buff' memory handlers.
4 *
5 * Authors: Alan Cox <alan@lxorguk.ukuu.org.uk>
6 * Florian La Roche <rzsfl@rz.uni-sb.de>
7 *
8 * Fixes:
9 * Alan Cox : Fixed the worst of the load
10 * balancer bugs.
11 * Dave Platt : Interrupt stacking fix.
12 * Richard Kooijman : Timestamp fixes.
13 * Alan Cox : Changed buffer format.
14 * Alan Cox : destructor hook for AF_UNIX etc.
15 * Linus Torvalds : Better skb_clone.
16 * Alan Cox : Added skb_copy.
17 * Alan Cox : Added all the changed routines Linus
18 * only put in the headers
19 * Ray VanTassle : Fixed --skb->lock in free
20 * Alan Cox : skb_copy copy arp field
21 * Andi Kleen : slabified it.
22 * Robert Olsson : Removed skb_head_pool
23 *
24 * NOTE:
25 * The __skb_ routines should be called with interrupts
26 * disabled, or you better be *real* sure that the operation is atomic
27 * with respect to whatever list is being frobbed (e.g. via lock_sock()
28 * or via disabling bottom half handlers, etc).
29 */
30
31/*
32 * The functions in this file will not compile correctly with gcc 2.4.x
33 */
34
35#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
36
37#include <linux/module.h>
38#include <linux/types.h>
39#include <linux/kernel.h>
40#include <linux/mm.h>
41#include <linux/interrupt.h>
42#include <linux/in.h>
43#include <linux/inet.h>
44#include <linux/slab.h>
45#include <linux/tcp.h>
46#include <linux/udp.h>
47#include <linux/sctp.h>
48#include <linux/netdevice.h>
49#ifdef CONFIG_NET_CLS_ACT
50#include <net/pkt_sched.h>
51#endif
52#include <linux/string.h>
53#include <linux/skbuff.h>
54#include <linux/skbuff_ref.h>
55#include <linux/splice.h>
56#include <linux/cache.h>
57#include <linux/rtnetlink.h>
58#include <linux/init.h>
59#include <linux/scatterlist.h>
60#include <linux/errqueue.h>
61#include <linux/prefetch.h>
62#include <linux/bitfield.h>
63#include <linux/if_vlan.h>
64#include <linux/mpls.h>
65#include <linux/kcov.h>
66#include <linux/iov_iter.h>
67
68#include <net/protocol.h>
69#include <net/dst.h>
70#include <net/sock.h>
71#include <net/checksum.h>
72#include <net/gro.h>
73#include <net/gso.h>
74#include <net/hotdata.h>
75#include <net/ip6_checksum.h>
76#include <net/xfrm.h>
77#include <net/mpls.h>
78#include <net/mptcp.h>
79#include <net/mctp.h>
80#include <net/page_pool/helpers.h>
81#include <net/dropreason.h>
82
83#include <linux/uaccess.h>
84#include <trace/events/skb.h>
85#include <linux/highmem.h>
86#include <linux/capability.h>
87#include <linux/user_namespace.h>
88#include <linux/indirect_call_wrapper.h>
89#include <linux/textsearch.h>
90
91#include "dev.h"
92#include "netmem_priv.h"
93#include "sock_destructor.h"
94
95#ifdef CONFIG_SKB_EXTENSIONS
96static struct kmem_cache *skbuff_ext_cache __ro_after_init;
97#endif
98
99#define GRO_MAX_HEAD_PAD (GRO_MAX_HEAD + NET_SKB_PAD + NET_IP_ALIGN)
100#define SKB_SMALL_HEAD_SIZE SKB_HEAD_ALIGN(max(MAX_TCP_HEADER, \
101 GRO_MAX_HEAD_PAD))
102
103/* We want SKB_SMALL_HEAD_CACHE_SIZE to not be a power of two.
104 * This should ensure that SKB_SMALL_HEAD_HEADROOM is a unique
105 * size, and we can differentiate heads from skb_small_head_cache
106 * vs system slabs by looking at their size (skb_end_offset()).
107 */
108#define SKB_SMALL_HEAD_CACHE_SIZE \
109 (is_power_of_2(SKB_SMALL_HEAD_SIZE) ? \
110 (SKB_SMALL_HEAD_SIZE + L1_CACHE_BYTES) : \
111 SKB_SMALL_HEAD_SIZE)
112
113#define SKB_SMALL_HEAD_HEADROOM \
114 SKB_WITH_OVERHEAD(SKB_SMALL_HEAD_CACHE_SIZE)
115
116/* kcm_write_msgs() relies on casting paged frags to bio_vec to use
117 * iov_iter_bvec(). These static asserts ensure the cast is valid is long as the
118 * netmem is a page.
119 */
120static_assert(offsetof(struct bio_vec, bv_page) ==
121 offsetof(skb_frag_t, netmem));
122static_assert(sizeof_field(struct bio_vec, bv_page) ==
123 sizeof_field(skb_frag_t, netmem));
124
125static_assert(offsetof(struct bio_vec, bv_len) == offsetof(skb_frag_t, len));
126static_assert(sizeof_field(struct bio_vec, bv_len) ==
127 sizeof_field(skb_frag_t, len));
128
129static_assert(offsetof(struct bio_vec, bv_offset) ==
130 offsetof(skb_frag_t, offset));
131static_assert(sizeof_field(struct bio_vec, bv_offset) ==
132 sizeof_field(skb_frag_t, offset));
133
134#undef FN
135#define FN(reason) [SKB_DROP_REASON_##reason] = #reason,
136static const char * const drop_reasons[] = {
137 [SKB_CONSUMED] = "CONSUMED",
138 DEFINE_DROP_REASON(FN, FN)
139};
140
141static const struct drop_reason_list drop_reasons_core = {
142 .reasons = drop_reasons,
143 .n_reasons = ARRAY_SIZE(drop_reasons),
144};
145
146const struct drop_reason_list __rcu *
147drop_reasons_by_subsys[SKB_DROP_REASON_SUBSYS_NUM] = {
148 [SKB_DROP_REASON_SUBSYS_CORE] = RCU_INITIALIZER(&drop_reasons_core),
149};
150EXPORT_SYMBOL(drop_reasons_by_subsys);
151
152/**
153 * drop_reasons_register_subsys - register another drop reason subsystem
154 * @subsys: the subsystem to register, must not be the core
155 * @list: the list of drop reasons within the subsystem, must point to
156 * a statically initialized list
157 */
158void drop_reasons_register_subsys(enum skb_drop_reason_subsys subsys,
159 const struct drop_reason_list *list)
160{
161 if (WARN(subsys <= SKB_DROP_REASON_SUBSYS_CORE ||
162 subsys >= ARRAY_SIZE(drop_reasons_by_subsys),
163 "invalid subsystem %d\n", subsys))
164 return;
165
166 /* must point to statically allocated memory, so INIT is OK */
167 RCU_INIT_POINTER(drop_reasons_by_subsys[subsys], list);
168}
169EXPORT_SYMBOL_GPL(drop_reasons_register_subsys);
170
171/**
172 * drop_reasons_unregister_subsys - unregister a drop reason subsystem
173 * @subsys: the subsystem to remove, must not be the core
174 *
175 * Note: This will synchronize_rcu() to ensure no users when it returns.
176 */
177void drop_reasons_unregister_subsys(enum skb_drop_reason_subsys subsys)
178{
179 if (WARN(subsys <= SKB_DROP_REASON_SUBSYS_CORE ||
180 subsys >= ARRAY_SIZE(drop_reasons_by_subsys),
181 "invalid subsystem %d\n", subsys))
182 return;
183
184 RCU_INIT_POINTER(drop_reasons_by_subsys[subsys], NULL);
185
186 synchronize_rcu();
187}
188EXPORT_SYMBOL_GPL(drop_reasons_unregister_subsys);
189
190/**
191 * skb_panic - private function for out-of-line support
192 * @skb: buffer
193 * @sz: size
194 * @addr: address
195 * @msg: skb_over_panic or skb_under_panic
196 *
197 * Out-of-line support for skb_put() and skb_push().
198 * Called via the wrapper skb_over_panic() or skb_under_panic().
199 * Keep out of line to prevent kernel bloat.
200 * __builtin_return_address is not used because it is not always reliable.
201 */
202static void skb_panic(struct sk_buff *skb, unsigned int sz, void *addr,
203 const char msg[])
204{
205 pr_emerg("%s: text:%px len:%d put:%d head:%px data:%px tail:%#lx end:%#lx dev:%s\n",
206 msg, addr, skb->len, sz, skb->head, skb->data,
207 (unsigned long)skb->tail, (unsigned long)skb->end,
208 skb->dev ? skb->dev->name : "<NULL>");
209 BUG();
210}
211
212static void skb_over_panic(struct sk_buff *skb, unsigned int sz, void *addr)
213{
214 skb_panic(skb, sz, addr, __func__);
215}
216
217static void skb_under_panic(struct sk_buff *skb, unsigned int sz, void *addr)
218{
219 skb_panic(skb, sz, addr, __func__);
220}
221
222#define NAPI_SKB_CACHE_SIZE 64
223#define NAPI_SKB_CACHE_BULK 16
224#define NAPI_SKB_CACHE_HALF (NAPI_SKB_CACHE_SIZE / 2)
225
226#if PAGE_SIZE == SZ_4K
227
228#define NAPI_HAS_SMALL_PAGE_FRAG 1
229#define NAPI_SMALL_PAGE_PFMEMALLOC(nc) ((nc).pfmemalloc)
230
231/* specialized page frag allocator using a single order 0 page
232 * and slicing it into 1K sized fragment. Constrained to systems
233 * with a very limited amount of 1K fragments fitting a single
234 * page - to avoid excessive truesize underestimation
235 */
236
237struct page_frag_1k {
238 void *va;
239 u16 offset;
240 bool pfmemalloc;
241};
242
243static void *page_frag_alloc_1k(struct page_frag_1k *nc, gfp_t gfp)
244{
245 struct page *page;
246 int offset;
247
248 offset = nc->offset - SZ_1K;
249 if (likely(offset >= 0))
250 goto use_frag;
251
252 page = alloc_pages_node(NUMA_NO_NODE, gfp, 0);
253 if (!page)
254 return NULL;
255
256 nc->va = page_address(page);
257 nc->pfmemalloc = page_is_pfmemalloc(page);
258 offset = PAGE_SIZE - SZ_1K;
259 page_ref_add(page, offset / SZ_1K);
260
261use_frag:
262 nc->offset = offset;
263 return nc->va + offset;
264}
265#else
266
267/* the small page is actually unused in this build; add dummy helpers
268 * to please the compiler and avoid later preprocessor's conditionals
269 */
270#define NAPI_HAS_SMALL_PAGE_FRAG 0
271#define NAPI_SMALL_PAGE_PFMEMALLOC(nc) false
272
273struct page_frag_1k {
274};
275
276static void *page_frag_alloc_1k(struct page_frag_1k *nc, gfp_t gfp_mask)
277{
278 return NULL;
279}
280
281#endif
282
283struct napi_alloc_cache {
284 local_lock_t bh_lock;
285 struct page_frag_cache page;
286 struct page_frag_1k page_small;
287 unsigned int skb_count;
288 void *skb_cache[NAPI_SKB_CACHE_SIZE];
289};
290
291static DEFINE_PER_CPU(struct page_frag_cache, netdev_alloc_cache);
292static DEFINE_PER_CPU(struct napi_alloc_cache, napi_alloc_cache) = {
293 .bh_lock = INIT_LOCAL_LOCK(bh_lock),
294};
295
296/* Double check that napi_get_frags() allocates skbs with
297 * skb->head being backed by slab, not a page fragment.
298 * This is to make sure bug fixed in 3226b158e67c
299 * ("net: avoid 32 x truesize under-estimation for tiny skbs")
300 * does not accidentally come back.
301 */
302void napi_get_frags_check(struct napi_struct *napi)
303{
304 struct sk_buff *skb;
305
306 local_bh_disable();
307 skb = napi_get_frags(napi);
308 WARN_ON_ONCE(!NAPI_HAS_SMALL_PAGE_FRAG && skb && skb->head_frag);
309 napi_free_frags(napi);
310 local_bh_enable();
311}
312
313void *__napi_alloc_frag_align(unsigned int fragsz, unsigned int align_mask)
314{
315 struct napi_alloc_cache *nc = this_cpu_ptr(&napi_alloc_cache);
316 void *data;
317
318 fragsz = SKB_DATA_ALIGN(fragsz);
319
320 local_lock_nested_bh(&napi_alloc_cache.bh_lock);
321 data = __page_frag_alloc_align(&nc->page, fragsz,
322 GFP_ATOMIC | __GFP_NOWARN, align_mask);
323 local_unlock_nested_bh(&napi_alloc_cache.bh_lock);
324 return data;
325
326}
327EXPORT_SYMBOL(__napi_alloc_frag_align);
328
329void *__netdev_alloc_frag_align(unsigned int fragsz, unsigned int align_mask)
330{
331 void *data;
332
333 if (in_hardirq() || irqs_disabled()) {
334 struct page_frag_cache *nc = this_cpu_ptr(&netdev_alloc_cache);
335
336 fragsz = SKB_DATA_ALIGN(fragsz);
337 data = __page_frag_alloc_align(nc, fragsz,
338 GFP_ATOMIC | __GFP_NOWARN,
339 align_mask);
340 } else {
341 local_bh_disable();
342 data = __napi_alloc_frag_align(fragsz, align_mask);
343 local_bh_enable();
344 }
345 return data;
346}
347EXPORT_SYMBOL(__netdev_alloc_frag_align);
348
349static struct sk_buff *napi_skb_cache_get(void)
350{
351 struct napi_alloc_cache *nc = this_cpu_ptr(&napi_alloc_cache);
352 struct sk_buff *skb;
353
354 local_lock_nested_bh(&napi_alloc_cache.bh_lock);
355 if (unlikely(!nc->skb_count)) {
356 nc->skb_count = kmem_cache_alloc_bulk(net_hotdata.skbuff_cache,
357 GFP_ATOMIC | __GFP_NOWARN,
358 NAPI_SKB_CACHE_BULK,
359 nc->skb_cache);
360 if (unlikely(!nc->skb_count)) {
361 local_unlock_nested_bh(&napi_alloc_cache.bh_lock);
362 return NULL;
363 }
364 }
365
366 skb = nc->skb_cache[--nc->skb_count];
367 local_unlock_nested_bh(&napi_alloc_cache.bh_lock);
368 kasan_mempool_unpoison_object(skb, kmem_cache_size(net_hotdata.skbuff_cache));
369
370 return skb;
371}
372
373static inline void __finalize_skb_around(struct sk_buff *skb, void *data,
374 unsigned int size)
375{
376 struct skb_shared_info *shinfo;
377
378 size -= SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
379
380 /* Assumes caller memset cleared SKB */
381 skb->truesize = SKB_TRUESIZE(size);
382 refcount_set(&skb->users, 1);
383 skb->head = data;
384 skb->data = data;
385 skb_reset_tail_pointer(skb);
386 skb_set_end_offset(skb, size);
387 skb->mac_header = (typeof(skb->mac_header))~0U;
388 skb->transport_header = (typeof(skb->transport_header))~0U;
389 skb->alloc_cpu = raw_smp_processor_id();
390 /* make sure we initialize shinfo sequentially */
391 shinfo = skb_shinfo(skb);
392 memset(shinfo, 0, offsetof(struct skb_shared_info, dataref));
393 atomic_set(&shinfo->dataref, 1);
394
395 skb_set_kcov_handle(skb, kcov_common_handle());
396}
397
398static inline void *__slab_build_skb(struct sk_buff *skb, void *data,
399 unsigned int *size)
400{
401 void *resized;
402
403 /* Must find the allocation size (and grow it to match). */
404 *size = ksize(data);
405 /* krealloc() will immediately return "data" when
406 * "ksize(data)" is requested: it is the existing upper
407 * bounds. As a result, GFP_ATOMIC will be ignored. Note
408 * that this "new" pointer needs to be passed back to the
409 * caller for use so the __alloc_size hinting will be
410 * tracked correctly.
411 */
412 resized = krealloc(data, *size, GFP_ATOMIC);
413 WARN_ON_ONCE(resized != data);
414 return resized;
415}
416
417/* build_skb() variant which can operate on slab buffers.
418 * Note that this should be used sparingly as slab buffers
419 * cannot be combined efficiently by GRO!
420 */
421struct sk_buff *slab_build_skb(void *data)
422{
423 struct sk_buff *skb;
424 unsigned int size;
425
426 skb = kmem_cache_alloc(net_hotdata.skbuff_cache,
427 GFP_ATOMIC | __GFP_NOWARN);
428 if (unlikely(!skb))
429 return NULL;
430
431 memset(skb, 0, offsetof(struct sk_buff, tail));
432 data = __slab_build_skb(skb, data, &size);
433 __finalize_skb_around(skb, data, size);
434
435 return skb;
436}
437EXPORT_SYMBOL(slab_build_skb);
438
439/* Caller must provide SKB that is memset cleared */
440static void __build_skb_around(struct sk_buff *skb, void *data,
441 unsigned int frag_size)
442{
443 unsigned int size = frag_size;
444
445 /* frag_size == 0 is considered deprecated now. Callers
446 * using slab buffer should use slab_build_skb() instead.
447 */
448 if (WARN_ONCE(size == 0, "Use slab_build_skb() instead"))
449 data = __slab_build_skb(skb, data, &size);
450
451 __finalize_skb_around(skb, data, size);
452}
453
454/**
455 * __build_skb - build a network buffer
456 * @data: data buffer provided by caller
457 * @frag_size: size of data (must not be 0)
458 *
459 * Allocate a new &sk_buff. Caller provides space holding head and
460 * skb_shared_info. @data must have been allocated from the page
461 * allocator or vmalloc(). (A @frag_size of 0 to indicate a kmalloc()
462 * allocation is deprecated, and callers should use slab_build_skb()
463 * instead.)
464 * The return is the new skb buffer.
465 * On a failure the return is %NULL, and @data is not freed.
466 * Notes :
467 * Before IO, driver allocates only data buffer where NIC put incoming frame
468 * Driver should add room at head (NET_SKB_PAD) and
469 * MUST add room at tail (SKB_DATA_ALIGN(skb_shared_info))
470 * After IO, driver calls build_skb(), to allocate sk_buff and populate it
471 * before giving packet to stack.
472 * RX rings only contains data buffers, not full skbs.
473 */
474struct sk_buff *__build_skb(void *data, unsigned int frag_size)
475{
476 struct sk_buff *skb;
477
478 skb = kmem_cache_alloc(net_hotdata.skbuff_cache,
479 GFP_ATOMIC | __GFP_NOWARN);
480 if (unlikely(!skb))
481 return NULL;
482
483 memset(skb, 0, offsetof(struct sk_buff, tail));
484 __build_skb_around(skb, data, frag_size);
485
486 return skb;
487}
488
489/* build_skb() is wrapper over __build_skb(), that specifically
490 * takes care of skb->head and skb->pfmemalloc
491 */
492struct sk_buff *build_skb(void *data, unsigned int frag_size)
493{
494 struct sk_buff *skb = __build_skb(data, frag_size);
495
496 if (likely(skb && frag_size)) {
497 skb->head_frag = 1;
498 skb_propagate_pfmemalloc(virt_to_head_page(data), skb);
499 }
500 return skb;
501}
502EXPORT_SYMBOL(build_skb);
503
504/**
505 * build_skb_around - build a network buffer around provided skb
506 * @skb: sk_buff provide by caller, must be memset cleared
507 * @data: data buffer provided by caller
508 * @frag_size: size of data
509 */
510struct sk_buff *build_skb_around(struct sk_buff *skb,
511 void *data, unsigned int frag_size)
512{
513 if (unlikely(!skb))
514 return NULL;
515
516 __build_skb_around(skb, data, frag_size);
517
518 if (frag_size) {
519 skb->head_frag = 1;
520 skb_propagate_pfmemalloc(virt_to_head_page(data), skb);
521 }
522 return skb;
523}
524EXPORT_SYMBOL(build_skb_around);
525
526/**
527 * __napi_build_skb - build a network buffer
528 * @data: data buffer provided by caller
529 * @frag_size: size of data
530 *
531 * Version of __build_skb() that uses NAPI percpu caches to obtain
532 * skbuff_head instead of inplace allocation.
533 *
534 * Returns a new &sk_buff on success, %NULL on allocation failure.
535 */
536static struct sk_buff *__napi_build_skb(void *data, unsigned int frag_size)
537{
538 struct sk_buff *skb;
539
540 skb = napi_skb_cache_get();
541 if (unlikely(!skb))
542 return NULL;
543
544 memset(skb, 0, offsetof(struct sk_buff, tail));
545 __build_skb_around(skb, data, frag_size);
546
547 return skb;
548}
549
550/**
551 * napi_build_skb - build a network buffer
552 * @data: data buffer provided by caller
553 * @frag_size: size of data
554 *
555 * Version of __napi_build_skb() that takes care of skb->head_frag
556 * and skb->pfmemalloc when the data is a page or page fragment.
557 *
558 * Returns a new &sk_buff on success, %NULL on allocation failure.
559 */
560struct sk_buff *napi_build_skb(void *data, unsigned int frag_size)
561{
562 struct sk_buff *skb = __napi_build_skb(data, frag_size);
563
564 if (likely(skb) && frag_size) {
565 skb->head_frag = 1;
566 skb_propagate_pfmemalloc(virt_to_head_page(data), skb);
567 }
568
569 return skb;
570}
571EXPORT_SYMBOL(napi_build_skb);
572
573/*
574 * kmalloc_reserve is a wrapper around kmalloc_node_track_caller that tells
575 * the caller if emergency pfmemalloc reserves are being used. If it is and
576 * the socket is later found to be SOCK_MEMALLOC then PFMEMALLOC reserves
577 * may be used. Otherwise, the packet data may be discarded until enough
578 * memory is free
579 */
580static void *kmalloc_reserve(unsigned int *size, gfp_t flags, int node,
581 bool *pfmemalloc)
582{
583 bool ret_pfmemalloc = false;
584 size_t obj_size;
585 void *obj;
586
587 obj_size = SKB_HEAD_ALIGN(*size);
588 if (obj_size <= SKB_SMALL_HEAD_CACHE_SIZE &&
589 !(flags & KMALLOC_NOT_NORMAL_BITS)) {
590 obj = kmem_cache_alloc_node(net_hotdata.skb_small_head_cache,
591 flags | __GFP_NOMEMALLOC | __GFP_NOWARN,
592 node);
593 *size = SKB_SMALL_HEAD_CACHE_SIZE;
594 if (obj || !(gfp_pfmemalloc_allowed(flags)))
595 goto out;
596 /* Try again but now we are using pfmemalloc reserves */
597 ret_pfmemalloc = true;
598 obj = kmem_cache_alloc_node(net_hotdata.skb_small_head_cache, flags, node);
599 goto out;
600 }
601
602 obj_size = kmalloc_size_roundup(obj_size);
603 /* The following cast might truncate high-order bits of obj_size, this
604 * is harmless because kmalloc(obj_size >= 2^32) will fail anyway.
605 */
606 *size = (unsigned int)obj_size;
607
608 /*
609 * Try a regular allocation, when that fails and we're not entitled
610 * to the reserves, fail.
611 */
612 obj = kmalloc_node_track_caller(obj_size,
613 flags | __GFP_NOMEMALLOC | __GFP_NOWARN,
614 node);
615 if (obj || !(gfp_pfmemalloc_allowed(flags)))
616 goto out;
617
618 /* Try again but now we are using pfmemalloc reserves */
619 ret_pfmemalloc = true;
620 obj = kmalloc_node_track_caller(obj_size, flags, node);
621
622out:
623 if (pfmemalloc)
624 *pfmemalloc = ret_pfmemalloc;
625
626 return obj;
627}
628
629/* Allocate a new skbuff. We do this ourselves so we can fill in a few
630 * 'private' fields and also do memory statistics to find all the
631 * [BEEP] leaks.
632 *
633 */
634
635/**
636 * __alloc_skb - allocate a network buffer
637 * @size: size to allocate
638 * @gfp_mask: allocation mask
639 * @flags: If SKB_ALLOC_FCLONE is set, allocate from fclone cache
640 * instead of head cache and allocate a cloned (child) skb.
641 * If SKB_ALLOC_RX is set, __GFP_MEMALLOC will be used for
642 * allocations in case the data is required for writeback
643 * @node: numa node to allocate memory on
644 *
645 * Allocate a new &sk_buff. The returned buffer has no headroom and a
646 * tail room of at least size bytes. The object has a reference count
647 * of one. The return is the buffer. On a failure the return is %NULL.
648 *
649 * Buffers may only be allocated from interrupts using a @gfp_mask of
650 * %GFP_ATOMIC.
651 */
652struct sk_buff *__alloc_skb(unsigned int size, gfp_t gfp_mask,
653 int flags, int node)
654{
655 struct kmem_cache *cache;
656 struct sk_buff *skb;
657 bool pfmemalloc;
658 u8 *data;
659
660 cache = (flags & SKB_ALLOC_FCLONE)
661 ? net_hotdata.skbuff_fclone_cache : net_hotdata.skbuff_cache;
662
663 if (sk_memalloc_socks() && (flags & SKB_ALLOC_RX))
664 gfp_mask |= __GFP_MEMALLOC;
665
666 /* Get the HEAD */
667 if ((flags & (SKB_ALLOC_FCLONE | SKB_ALLOC_NAPI)) == SKB_ALLOC_NAPI &&
668 likely(node == NUMA_NO_NODE || node == numa_mem_id()))
669 skb = napi_skb_cache_get();
670 else
671 skb = kmem_cache_alloc_node(cache, gfp_mask & ~GFP_DMA, node);
672 if (unlikely(!skb))
673 return NULL;
674 prefetchw(skb);
675
676 /* We do our best to align skb_shared_info on a separate cache
677 * line. It usually works because kmalloc(X > SMP_CACHE_BYTES) gives
678 * aligned memory blocks, unless SLUB/SLAB debug is enabled.
679 * Both skb->head and skb_shared_info are cache line aligned.
680 */
681 data = kmalloc_reserve(&size, gfp_mask, node, &pfmemalloc);
682 if (unlikely(!data))
683 goto nodata;
684 /* kmalloc_size_roundup() might give us more room than requested.
685 * Put skb_shared_info exactly at the end of allocated zone,
686 * to allow max possible filling before reallocation.
687 */
688 prefetchw(data + SKB_WITH_OVERHEAD(size));
689
690 /*
691 * Only clear those fields we need to clear, not those that we will
692 * actually initialise below. Hence, don't put any more fields after
693 * the tail pointer in struct sk_buff!
694 */
695 memset(skb, 0, offsetof(struct sk_buff, tail));
696 __build_skb_around(skb, data, size);
697 skb->pfmemalloc = pfmemalloc;
698
699 if (flags & SKB_ALLOC_FCLONE) {
700 struct sk_buff_fclones *fclones;
701
702 fclones = container_of(skb, struct sk_buff_fclones, skb1);
703
704 skb->fclone = SKB_FCLONE_ORIG;
705 refcount_set(&fclones->fclone_ref, 1);
706 }
707
708 return skb;
709
710nodata:
711 kmem_cache_free(cache, skb);
712 return NULL;
713}
714EXPORT_SYMBOL(__alloc_skb);
715
716/**
717 * __netdev_alloc_skb - allocate an skbuff for rx on a specific device
718 * @dev: network device to receive on
719 * @len: length to allocate
720 * @gfp_mask: get_free_pages mask, passed to alloc_skb
721 *
722 * Allocate a new &sk_buff and assign it a usage count of one. The
723 * buffer has NET_SKB_PAD headroom built in. Users should allocate
724 * the headroom they think they need without accounting for the
725 * built in space. The built in space is used for optimisations.
726 *
727 * %NULL is returned if there is no free memory.
728 */
729struct sk_buff *__netdev_alloc_skb(struct net_device *dev, unsigned int len,
730 gfp_t gfp_mask)
731{
732 struct page_frag_cache *nc;
733 struct sk_buff *skb;
734 bool pfmemalloc;
735 void *data;
736
737 len += NET_SKB_PAD;
738
739 /* If requested length is either too small or too big,
740 * we use kmalloc() for skb->head allocation.
741 */
742 if (len <= SKB_WITH_OVERHEAD(SKB_SMALL_HEAD_CACHE_SIZE) ||
743 len > SKB_WITH_OVERHEAD(PAGE_SIZE) ||
744 (gfp_mask & (__GFP_DIRECT_RECLAIM | GFP_DMA))) {
745 skb = __alloc_skb(len, gfp_mask, SKB_ALLOC_RX, NUMA_NO_NODE);
746 if (!skb)
747 goto skb_fail;
748 goto skb_success;
749 }
750
751 len = SKB_HEAD_ALIGN(len);
752
753 if (sk_memalloc_socks())
754 gfp_mask |= __GFP_MEMALLOC;
755
756 if (in_hardirq() || irqs_disabled()) {
757 nc = this_cpu_ptr(&netdev_alloc_cache);
758 data = page_frag_alloc(nc, len, gfp_mask);
759 pfmemalloc = page_frag_cache_is_pfmemalloc(nc);
760 } else {
761 local_bh_disable();
762 local_lock_nested_bh(&napi_alloc_cache.bh_lock);
763
764 nc = this_cpu_ptr(&napi_alloc_cache.page);
765 data = page_frag_alloc(nc, len, gfp_mask);
766 pfmemalloc = page_frag_cache_is_pfmemalloc(nc);
767
768 local_unlock_nested_bh(&napi_alloc_cache.bh_lock);
769 local_bh_enable();
770 }
771
772 if (unlikely(!data))
773 return NULL;
774
775 skb = __build_skb(data, len);
776 if (unlikely(!skb)) {
777 skb_free_frag(data);
778 return NULL;
779 }
780
781 if (pfmemalloc)
782 skb->pfmemalloc = 1;
783 skb->head_frag = 1;
784
785skb_success:
786 skb_reserve(skb, NET_SKB_PAD);
787 skb->dev = dev;
788
789skb_fail:
790 return skb;
791}
792EXPORT_SYMBOL(__netdev_alloc_skb);
793
794/**
795 * napi_alloc_skb - allocate skbuff for rx in a specific NAPI instance
796 * @napi: napi instance this buffer was allocated for
797 * @len: length to allocate
798 *
799 * Allocate a new sk_buff for use in NAPI receive. This buffer will
800 * attempt to allocate the head from a special reserved region used
801 * only for NAPI Rx allocation. By doing this we can save several
802 * CPU cycles by avoiding having to disable and re-enable IRQs.
803 *
804 * %NULL is returned if there is no free memory.
805 */
806struct sk_buff *napi_alloc_skb(struct napi_struct *napi, unsigned int len)
807{
808 gfp_t gfp_mask = GFP_ATOMIC | __GFP_NOWARN;
809 struct napi_alloc_cache *nc;
810 struct sk_buff *skb;
811 bool pfmemalloc;
812 void *data;
813
814 DEBUG_NET_WARN_ON_ONCE(!in_softirq());
815 len += NET_SKB_PAD + NET_IP_ALIGN;
816
817 /* If requested length is either too small or too big,
818 * we use kmalloc() for skb->head allocation.
819 * When the small frag allocator is available, prefer it over kmalloc
820 * for small fragments
821 */
822 if ((!NAPI_HAS_SMALL_PAGE_FRAG &&
823 len <= SKB_WITH_OVERHEAD(SKB_SMALL_HEAD_CACHE_SIZE)) ||
824 len > SKB_WITH_OVERHEAD(PAGE_SIZE) ||
825 (gfp_mask & (__GFP_DIRECT_RECLAIM | GFP_DMA))) {
826 skb = __alloc_skb(len, gfp_mask, SKB_ALLOC_RX | SKB_ALLOC_NAPI,
827 NUMA_NO_NODE);
828 if (!skb)
829 goto skb_fail;
830 goto skb_success;
831 }
832
833 if (sk_memalloc_socks())
834 gfp_mask |= __GFP_MEMALLOC;
835
836 local_lock_nested_bh(&napi_alloc_cache.bh_lock);
837 nc = this_cpu_ptr(&napi_alloc_cache);
838 if (NAPI_HAS_SMALL_PAGE_FRAG && len <= SKB_WITH_OVERHEAD(1024)) {
839 /* we are artificially inflating the allocation size, but
840 * that is not as bad as it may look like, as:
841 * - 'len' less than GRO_MAX_HEAD makes little sense
842 * - On most systems, larger 'len' values lead to fragment
843 * size above 512 bytes
844 * - kmalloc would use the kmalloc-1k slab for such values
845 * - Builds with smaller GRO_MAX_HEAD will very likely do
846 * little networking, as that implies no WiFi and no
847 * tunnels support, and 32 bits arches.
848 */
849 len = SZ_1K;
850
851 data = page_frag_alloc_1k(&nc->page_small, gfp_mask);
852 pfmemalloc = NAPI_SMALL_PAGE_PFMEMALLOC(nc->page_small);
853 } else {
854 len = SKB_HEAD_ALIGN(len);
855
856 data = page_frag_alloc(&nc->page, len, gfp_mask);
857 pfmemalloc = page_frag_cache_is_pfmemalloc(&nc->page);
858 }
859 local_unlock_nested_bh(&napi_alloc_cache.bh_lock);
860
861 if (unlikely(!data))
862 return NULL;
863
864 skb = __napi_build_skb(data, len);
865 if (unlikely(!skb)) {
866 skb_free_frag(data);
867 return NULL;
868 }
869
870 if (pfmemalloc)
871 skb->pfmemalloc = 1;
872 skb->head_frag = 1;
873
874skb_success:
875 skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN);
876 skb->dev = napi->dev;
877
878skb_fail:
879 return skb;
880}
881EXPORT_SYMBOL(napi_alloc_skb);
882
883void skb_add_rx_frag_netmem(struct sk_buff *skb, int i, netmem_ref netmem,
884 int off, int size, unsigned int truesize)
885{
886 DEBUG_NET_WARN_ON_ONCE(size > truesize);
887
888 skb_fill_netmem_desc(skb, i, netmem, off, size);
889 skb->len += size;
890 skb->data_len += size;
891 skb->truesize += truesize;
892}
893EXPORT_SYMBOL(skb_add_rx_frag_netmem);
894
895void skb_coalesce_rx_frag(struct sk_buff *skb, int i, int size,
896 unsigned int truesize)
897{
898 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
899
900 DEBUG_NET_WARN_ON_ONCE(size > truesize);
901
902 skb_frag_size_add(frag, size);
903 skb->len += size;
904 skb->data_len += size;
905 skb->truesize += truesize;
906}
907EXPORT_SYMBOL(skb_coalesce_rx_frag);
908
909static void skb_drop_list(struct sk_buff **listp)
910{
911 kfree_skb_list(*listp);
912 *listp = NULL;
913}
914
915static inline void skb_drop_fraglist(struct sk_buff *skb)
916{
917 skb_drop_list(&skb_shinfo(skb)->frag_list);
918}
919
920static void skb_clone_fraglist(struct sk_buff *skb)
921{
922 struct sk_buff *list;
923
924 skb_walk_frags(skb, list)
925 skb_get(list);
926}
927
928static bool is_pp_netmem(netmem_ref netmem)
929{
930 return (netmem_get_pp_magic(netmem) & ~0x3UL) == PP_SIGNATURE;
931}
932
933int skb_pp_cow_data(struct page_pool *pool, struct sk_buff **pskb,
934 unsigned int headroom)
935{
936#if IS_ENABLED(CONFIG_PAGE_POOL)
937 u32 size, truesize, len, max_head_size, off;
938 struct sk_buff *skb = *pskb, *nskb;
939 int err, i, head_off;
940 void *data;
941
942 /* XDP does not support fraglist so we need to linearize
943 * the skb.
944 */
945 if (skb_has_frag_list(skb))
946 return -EOPNOTSUPP;
947
948 max_head_size = SKB_WITH_OVERHEAD(PAGE_SIZE - headroom);
949 if (skb->len > max_head_size + MAX_SKB_FRAGS * PAGE_SIZE)
950 return -ENOMEM;
951
952 size = min_t(u32, skb->len, max_head_size);
953 truesize = SKB_HEAD_ALIGN(size) + headroom;
954 data = page_pool_dev_alloc_va(pool, &truesize);
955 if (!data)
956 return -ENOMEM;
957
958 nskb = napi_build_skb(data, truesize);
959 if (!nskb) {
960 page_pool_free_va(pool, data, true);
961 return -ENOMEM;
962 }
963
964 skb_reserve(nskb, headroom);
965 skb_copy_header(nskb, skb);
966 skb_mark_for_recycle(nskb);
967
968 err = skb_copy_bits(skb, 0, nskb->data, size);
969 if (err) {
970 consume_skb(nskb);
971 return err;
972 }
973 skb_put(nskb, size);
974
975 head_off = skb_headroom(nskb) - skb_headroom(skb);
976 skb_headers_offset_update(nskb, head_off);
977
978 off = size;
979 len = skb->len - off;
980 for (i = 0; i < MAX_SKB_FRAGS && off < skb->len; i++) {
981 struct page *page;
982 u32 page_off;
983
984 size = min_t(u32, len, PAGE_SIZE);
985 truesize = size;
986
987 page = page_pool_dev_alloc(pool, &page_off, &truesize);
988 if (!page) {
989 consume_skb(nskb);
990 return -ENOMEM;
991 }
992
993 skb_add_rx_frag(nskb, i, page, page_off, size, truesize);
994 err = skb_copy_bits(skb, off, page_address(page) + page_off,
995 size);
996 if (err) {
997 consume_skb(nskb);
998 return err;
999 }
1000
1001 len -= size;
1002 off += size;
1003 }
1004
1005 consume_skb(skb);
1006 *pskb = nskb;
1007
1008 return 0;
1009#else
1010 return -EOPNOTSUPP;
1011#endif
1012}
1013EXPORT_SYMBOL(skb_pp_cow_data);
1014
1015int skb_cow_data_for_xdp(struct page_pool *pool, struct sk_buff **pskb,
1016 struct bpf_prog *prog)
1017{
1018 if (!prog->aux->xdp_has_frags)
1019 return -EINVAL;
1020
1021 return skb_pp_cow_data(pool, pskb, XDP_PACKET_HEADROOM);
1022}
1023EXPORT_SYMBOL(skb_cow_data_for_xdp);
1024
1025#if IS_ENABLED(CONFIG_PAGE_POOL)
1026bool napi_pp_put_page(netmem_ref netmem)
1027{
1028 netmem = netmem_compound_head(netmem);
1029
1030 /* page->pp_magic is OR'ed with PP_SIGNATURE after the allocation
1031 * in order to preserve any existing bits, such as bit 0 for the
1032 * head page of compound page and bit 1 for pfmemalloc page, so
1033 * mask those bits for freeing side when doing below checking,
1034 * and page_is_pfmemalloc() is checked in __page_pool_put_page()
1035 * to avoid recycling the pfmemalloc page.
1036 */
1037 if (unlikely(!is_pp_netmem(netmem)))
1038 return false;
1039
1040 page_pool_put_full_netmem(netmem_get_pp(netmem), netmem, false);
1041
1042 return true;
1043}
1044EXPORT_SYMBOL(napi_pp_put_page);
1045#endif
1046
1047static bool skb_pp_recycle(struct sk_buff *skb, void *data)
1048{
1049 if (!IS_ENABLED(CONFIG_PAGE_POOL) || !skb->pp_recycle)
1050 return false;
1051 return napi_pp_put_page(page_to_netmem(virt_to_page(data)));
1052}
1053
1054/**
1055 * skb_pp_frag_ref() - Increase fragment references of a page pool aware skb
1056 * @skb: page pool aware skb
1057 *
1058 * Increase the fragment reference count (pp_ref_count) of a skb. This is
1059 * intended to gain fragment references only for page pool aware skbs,
1060 * i.e. when skb->pp_recycle is true, and not for fragments in a
1061 * non-pp-recycling skb. It has a fallback to increase references on normal
1062 * pages, as page pool aware skbs may also have normal page fragments.
1063 */
1064static int skb_pp_frag_ref(struct sk_buff *skb)
1065{
1066 struct skb_shared_info *shinfo;
1067 netmem_ref head_netmem;
1068 int i;
1069
1070 if (!skb->pp_recycle)
1071 return -EINVAL;
1072
1073 shinfo = skb_shinfo(skb);
1074
1075 for (i = 0; i < shinfo->nr_frags; i++) {
1076 head_netmem = netmem_compound_head(shinfo->frags[i].netmem);
1077 if (likely(is_pp_netmem(head_netmem)))
1078 page_pool_ref_netmem(head_netmem);
1079 else
1080 page_ref_inc(netmem_to_page(head_netmem));
1081 }
1082 return 0;
1083}
1084
1085static void skb_kfree_head(void *head, unsigned int end_offset)
1086{
1087 if (end_offset == SKB_SMALL_HEAD_HEADROOM)
1088 kmem_cache_free(net_hotdata.skb_small_head_cache, head);
1089 else
1090 kfree(head);
1091}
1092
1093static void skb_free_head(struct sk_buff *skb)
1094{
1095 unsigned char *head = skb->head;
1096
1097 if (skb->head_frag) {
1098 if (skb_pp_recycle(skb, head))
1099 return;
1100 skb_free_frag(head);
1101 } else {
1102 skb_kfree_head(head, skb_end_offset(skb));
1103 }
1104}
1105
1106static void skb_release_data(struct sk_buff *skb, enum skb_drop_reason reason)
1107{
1108 struct skb_shared_info *shinfo = skb_shinfo(skb);
1109 int i;
1110
1111 if (!skb_data_unref(skb, shinfo))
1112 goto exit;
1113
1114 if (skb_zcopy(skb)) {
1115 bool skip_unref = shinfo->flags & SKBFL_MANAGED_FRAG_REFS;
1116
1117 skb_zcopy_clear(skb, true);
1118 if (skip_unref)
1119 goto free_head;
1120 }
1121
1122 for (i = 0; i < shinfo->nr_frags; i++)
1123 __skb_frag_unref(&shinfo->frags[i], skb->pp_recycle);
1124
1125free_head:
1126 if (shinfo->frag_list)
1127 kfree_skb_list_reason(shinfo->frag_list, reason);
1128
1129 skb_free_head(skb);
1130exit:
1131 /* When we clone an SKB we copy the reycling bit. The pp_recycle
1132 * bit is only set on the head though, so in order to avoid races
1133 * while trying to recycle fragments on __skb_frag_unref() we need
1134 * to make one SKB responsible for triggering the recycle path.
1135 * So disable the recycling bit if an SKB is cloned and we have
1136 * additional references to the fragmented part of the SKB.
1137 * Eventually the last SKB will have the recycling bit set and it's
1138 * dataref set to 0, which will trigger the recycling
1139 */
1140 skb->pp_recycle = 0;
1141}
1142
1143/*
1144 * Free an skbuff by memory without cleaning the state.
1145 */
1146static void kfree_skbmem(struct sk_buff *skb)
1147{
1148 struct sk_buff_fclones *fclones;
1149
1150 switch (skb->fclone) {
1151 case SKB_FCLONE_UNAVAILABLE:
1152 kmem_cache_free(net_hotdata.skbuff_cache, skb);
1153 return;
1154
1155 case SKB_FCLONE_ORIG:
1156 fclones = container_of(skb, struct sk_buff_fclones, skb1);
1157
1158 /* We usually free the clone (TX completion) before original skb
1159 * This test would have no chance to be true for the clone,
1160 * while here, branch prediction will be good.
1161 */
1162 if (refcount_read(&fclones->fclone_ref) == 1)
1163 goto fastpath;
1164 break;
1165
1166 default: /* SKB_FCLONE_CLONE */
1167 fclones = container_of(skb, struct sk_buff_fclones, skb2);
1168 break;
1169 }
1170 if (!refcount_dec_and_test(&fclones->fclone_ref))
1171 return;
1172fastpath:
1173 kmem_cache_free(net_hotdata.skbuff_fclone_cache, fclones);
1174}
1175
1176void skb_release_head_state(struct sk_buff *skb)
1177{
1178 skb_dst_drop(skb);
1179 if (skb->destructor) {
1180 DEBUG_NET_WARN_ON_ONCE(in_hardirq());
1181 skb->destructor(skb);
1182 }
1183#if IS_ENABLED(CONFIG_NF_CONNTRACK)
1184 nf_conntrack_put(skb_nfct(skb));
1185#endif
1186 skb_ext_put(skb);
1187}
1188
1189/* Free everything but the sk_buff shell. */
1190static void skb_release_all(struct sk_buff *skb, enum skb_drop_reason reason)
1191{
1192 skb_release_head_state(skb);
1193 if (likely(skb->head))
1194 skb_release_data(skb, reason);
1195}
1196
1197/**
1198 * __kfree_skb - private function
1199 * @skb: buffer
1200 *
1201 * Free an sk_buff. Release anything attached to the buffer.
1202 * Clean the state. This is an internal helper function. Users should
1203 * always call kfree_skb
1204 */
1205
1206void __kfree_skb(struct sk_buff *skb)
1207{
1208 skb_release_all(skb, SKB_DROP_REASON_NOT_SPECIFIED);
1209 kfree_skbmem(skb);
1210}
1211EXPORT_SYMBOL(__kfree_skb);
1212
1213static __always_inline
1214bool __sk_skb_reason_drop(struct sock *sk, struct sk_buff *skb,
1215 enum skb_drop_reason reason)
1216{
1217 if (unlikely(!skb_unref(skb)))
1218 return false;
1219
1220 DEBUG_NET_WARN_ON_ONCE(reason == SKB_NOT_DROPPED_YET ||
1221 u32_get_bits(reason,
1222 SKB_DROP_REASON_SUBSYS_MASK) >=
1223 SKB_DROP_REASON_SUBSYS_NUM);
1224
1225 if (reason == SKB_CONSUMED)
1226 trace_consume_skb(skb, __builtin_return_address(0));
1227 else
1228 trace_kfree_skb(skb, __builtin_return_address(0), reason, sk);
1229 return true;
1230}
1231
1232/**
1233 * sk_skb_reason_drop - free an sk_buff with special reason
1234 * @sk: the socket to receive @skb, or NULL if not applicable
1235 * @skb: buffer to free
1236 * @reason: reason why this skb is dropped
1237 *
1238 * Drop a reference to the buffer and free it if the usage count has hit
1239 * zero. Meanwhile, pass the receiving socket and drop reason to
1240 * 'kfree_skb' tracepoint.
1241 */
1242void __fix_address
1243sk_skb_reason_drop(struct sock *sk, struct sk_buff *skb, enum skb_drop_reason reason)
1244{
1245 if (__sk_skb_reason_drop(sk, skb, reason))
1246 __kfree_skb(skb);
1247}
1248EXPORT_SYMBOL(sk_skb_reason_drop);
1249
1250#define KFREE_SKB_BULK_SIZE 16
1251
1252struct skb_free_array {
1253 unsigned int skb_count;
1254 void *skb_array[KFREE_SKB_BULK_SIZE];
1255};
1256
1257static void kfree_skb_add_bulk(struct sk_buff *skb,
1258 struct skb_free_array *sa,
1259 enum skb_drop_reason reason)
1260{
1261 /* if SKB is a clone, don't handle this case */
1262 if (unlikely(skb->fclone != SKB_FCLONE_UNAVAILABLE)) {
1263 __kfree_skb(skb);
1264 return;
1265 }
1266
1267 skb_release_all(skb, reason);
1268 sa->skb_array[sa->skb_count++] = skb;
1269
1270 if (unlikely(sa->skb_count == KFREE_SKB_BULK_SIZE)) {
1271 kmem_cache_free_bulk(net_hotdata.skbuff_cache, KFREE_SKB_BULK_SIZE,
1272 sa->skb_array);
1273 sa->skb_count = 0;
1274 }
1275}
1276
1277void __fix_address
1278kfree_skb_list_reason(struct sk_buff *segs, enum skb_drop_reason reason)
1279{
1280 struct skb_free_array sa;
1281
1282 sa.skb_count = 0;
1283
1284 while (segs) {
1285 struct sk_buff *next = segs->next;
1286
1287 if (__sk_skb_reason_drop(NULL, segs, reason)) {
1288 skb_poison_list(segs);
1289 kfree_skb_add_bulk(segs, &sa, reason);
1290 }
1291
1292 segs = next;
1293 }
1294
1295 if (sa.skb_count)
1296 kmem_cache_free_bulk(net_hotdata.skbuff_cache, sa.skb_count, sa.skb_array);
1297}
1298EXPORT_SYMBOL(kfree_skb_list_reason);
1299
1300/* Dump skb information and contents.
1301 *
1302 * Must only be called from net_ratelimit()-ed paths.
1303 *
1304 * Dumps whole packets if full_pkt, only headers otherwise.
1305 */
1306void skb_dump(const char *level, const struct sk_buff *skb, bool full_pkt)
1307{
1308 struct skb_shared_info *sh = skb_shinfo(skb);
1309 struct net_device *dev = skb->dev;
1310 struct sock *sk = skb->sk;
1311 struct sk_buff *list_skb;
1312 bool has_mac, has_trans;
1313 int headroom, tailroom;
1314 int i, len, seg_len;
1315
1316 if (full_pkt)
1317 len = skb->len;
1318 else
1319 len = min_t(int, skb->len, MAX_HEADER + 128);
1320
1321 headroom = skb_headroom(skb);
1322 tailroom = skb_tailroom(skb);
1323
1324 has_mac = skb_mac_header_was_set(skb);
1325 has_trans = skb_transport_header_was_set(skb);
1326
1327 printk("%sskb len=%u headroom=%u headlen=%u tailroom=%u\n"
1328 "mac=(%d,%d) mac_len=%u net=(%d,%d) trans=%d\n"
1329 "shinfo(txflags=%u nr_frags=%u gso(size=%hu type=%u segs=%hu))\n"
1330 "csum(0x%x start=%u offset=%u ip_summed=%u complete_sw=%u valid=%u level=%u)\n"
1331 "hash(0x%x sw=%u l4=%u) proto=0x%04x pkttype=%u iif=%d\n"
1332 "priority=0x%x mark=0x%x alloc_cpu=%u vlan_all=0x%x\n"
1333 "encapsulation=%d inner(proto=0x%04x, mac=%u, net=%u, trans=%u)\n",
1334 level, skb->len, headroom, skb_headlen(skb), tailroom,
1335 has_mac ? skb->mac_header : -1,
1336 has_mac ? skb_mac_header_len(skb) : -1,
1337 skb->mac_len,
1338 skb->network_header,
1339 has_trans ? skb_network_header_len(skb) : -1,
1340 has_trans ? skb->transport_header : -1,
1341 sh->tx_flags, sh->nr_frags,
1342 sh->gso_size, sh->gso_type, sh->gso_segs,
1343 skb->csum, skb->csum_start, skb->csum_offset, skb->ip_summed,
1344 skb->csum_complete_sw, skb->csum_valid, skb->csum_level,
1345 skb->hash, skb->sw_hash, skb->l4_hash,
1346 ntohs(skb->protocol), skb->pkt_type, skb->skb_iif,
1347 skb->priority, skb->mark, skb->alloc_cpu, skb->vlan_all,
1348 skb->encapsulation, skb->inner_protocol, skb->inner_mac_header,
1349 skb->inner_network_header, skb->inner_transport_header);
1350
1351 if (dev)
1352 printk("%sdev name=%s feat=%pNF\n",
1353 level, dev->name, &dev->features);
1354 if (sk)
1355 printk("%ssk family=%hu type=%u proto=%u\n",
1356 level, sk->sk_family, sk->sk_type, sk->sk_protocol);
1357
1358 if (full_pkt && headroom)
1359 print_hex_dump(level, "skb headroom: ", DUMP_PREFIX_OFFSET,
1360 16, 1, skb->head, headroom, false);
1361
1362 seg_len = min_t(int, skb_headlen(skb), len);
1363 if (seg_len)
1364 print_hex_dump(level, "skb linear: ", DUMP_PREFIX_OFFSET,
1365 16, 1, skb->data, seg_len, false);
1366 len -= seg_len;
1367
1368 if (full_pkt && tailroom)
1369 print_hex_dump(level, "skb tailroom: ", DUMP_PREFIX_OFFSET,
1370 16, 1, skb_tail_pointer(skb), tailroom, false);
1371
1372 for (i = 0; len && i < skb_shinfo(skb)->nr_frags; i++) {
1373 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
1374 u32 p_off, p_len, copied;
1375 struct page *p;
1376 u8 *vaddr;
1377
1378 if (skb_frag_is_net_iov(frag)) {
1379 printk("%sskb frag %d: not readable\n", level, i);
1380 len -= skb_frag_size(frag);
1381 if (!len)
1382 break;
1383 continue;
1384 }
1385
1386 skb_frag_foreach_page(frag, skb_frag_off(frag),
1387 skb_frag_size(frag), p, p_off, p_len,
1388 copied) {
1389 seg_len = min_t(int, p_len, len);
1390 vaddr = kmap_atomic(p);
1391 print_hex_dump(level, "skb frag: ",
1392 DUMP_PREFIX_OFFSET,
1393 16, 1, vaddr + p_off, seg_len, false);
1394 kunmap_atomic(vaddr);
1395 len -= seg_len;
1396 if (!len)
1397 break;
1398 }
1399 }
1400
1401 if (full_pkt && skb_has_frag_list(skb)) {
1402 printk("skb fraglist:\n");
1403 skb_walk_frags(skb, list_skb)
1404 skb_dump(level, list_skb, true);
1405 }
1406}
1407EXPORT_SYMBOL(skb_dump);
1408
1409/**
1410 * skb_tx_error - report an sk_buff xmit error
1411 * @skb: buffer that triggered an error
1412 *
1413 * Report xmit error if a device callback is tracking this skb.
1414 * skb must be freed afterwards.
1415 */
1416void skb_tx_error(struct sk_buff *skb)
1417{
1418 if (skb) {
1419 skb_zcopy_downgrade_managed(skb);
1420 skb_zcopy_clear(skb, true);
1421 }
1422}
1423EXPORT_SYMBOL(skb_tx_error);
1424
1425#ifdef CONFIG_TRACEPOINTS
1426/**
1427 * consume_skb - free an skbuff
1428 * @skb: buffer to free
1429 *
1430 * Drop a ref to the buffer and free it if the usage count has hit zero
1431 * Functions identically to kfree_skb, but kfree_skb assumes that the frame
1432 * is being dropped after a failure and notes that
1433 */
1434void consume_skb(struct sk_buff *skb)
1435{
1436 if (!skb_unref(skb))
1437 return;
1438
1439 trace_consume_skb(skb, __builtin_return_address(0));
1440 __kfree_skb(skb);
1441}
1442EXPORT_SYMBOL(consume_skb);
1443#endif
1444
1445/**
1446 * __consume_stateless_skb - free an skbuff, assuming it is stateless
1447 * @skb: buffer to free
1448 *
1449 * Alike consume_skb(), but this variant assumes that this is the last
1450 * skb reference and all the head states have been already dropped
1451 */
1452void __consume_stateless_skb(struct sk_buff *skb)
1453{
1454 trace_consume_skb(skb, __builtin_return_address(0));
1455 skb_release_data(skb, SKB_CONSUMED);
1456 kfree_skbmem(skb);
1457}
1458
1459static void napi_skb_cache_put(struct sk_buff *skb)
1460{
1461 struct napi_alloc_cache *nc = this_cpu_ptr(&napi_alloc_cache);
1462 u32 i;
1463
1464 if (!kasan_mempool_poison_object(skb))
1465 return;
1466
1467 local_lock_nested_bh(&napi_alloc_cache.bh_lock);
1468 nc->skb_cache[nc->skb_count++] = skb;
1469
1470 if (unlikely(nc->skb_count == NAPI_SKB_CACHE_SIZE)) {
1471 for (i = NAPI_SKB_CACHE_HALF; i < NAPI_SKB_CACHE_SIZE; i++)
1472 kasan_mempool_unpoison_object(nc->skb_cache[i],
1473 kmem_cache_size(net_hotdata.skbuff_cache));
1474
1475 kmem_cache_free_bulk(net_hotdata.skbuff_cache, NAPI_SKB_CACHE_HALF,
1476 nc->skb_cache + NAPI_SKB_CACHE_HALF);
1477 nc->skb_count = NAPI_SKB_CACHE_HALF;
1478 }
1479 local_unlock_nested_bh(&napi_alloc_cache.bh_lock);
1480}
1481
1482void __napi_kfree_skb(struct sk_buff *skb, enum skb_drop_reason reason)
1483{
1484 skb_release_all(skb, reason);
1485 napi_skb_cache_put(skb);
1486}
1487
1488void napi_skb_free_stolen_head(struct sk_buff *skb)
1489{
1490 if (unlikely(skb->slow_gro)) {
1491 nf_reset_ct(skb);
1492 skb_dst_drop(skb);
1493 skb_ext_put(skb);
1494 skb_orphan(skb);
1495 skb->slow_gro = 0;
1496 }
1497 napi_skb_cache_put(skb);
1498}
1499
1500void napi_consume_skb(struct sk_buff *skb, int budget)
1501{
1502 /* Zero budget indicate non-NAPI context called us, like netpoll */
1503 if (unlikely(!budget)) {
1504 dev_consume_skb_any(skb);
1505 return;
1506 }
1507
1508 DEBUG_NET_WARN_ON_ONCE(!in_softirq());
1509
1510 if (!skb_unref(skb))
1511 return;
1512
1513 /* if reaching here SKB is ready to free */
1514 trace_consume_skb(skb, __builtin_return_address(0));
1515
1516 /* if SKB is a clone, don't handle this case */
1517 if (skb->fclone != SKB_FCLONE_UNAVAILABLE) {
1518 __kfree_skb(skb);
1519 return;
1520 }
1521
1522 skb_release_all(skb, SKB_CONSUMED);
1523 napi_skb_cache_put(skb);
1524}
1525EXPORT_SYMBOL(napi_consume_skb);
1526
1527/* Make sure a field is contained by headers group */
1528#define CHECK_SKB_FIELD(field) \
1529 BUILD_BUG_ON(offsetof(struct sk_buff, field) != \
1530 offsetof(struct sk_buff, headers.field)); \
1531
1532static void __copy_skb_header(struct sk_buff *new, const struct sk_buff *old)
1533{
1534 new->tstamp = old->tstamp;
1535 /* We do not copy old->sk */
1536 new->dev = old->dev;
1537 memcpy(new->cb, old->cb, sizeof(old->cb));
1538 skb_dst_copy(new, old);
1539 __skb_ext_copy(new, old);
1540 __nf_copy(new, old, false);
1541
1542 /* Note : this field could be in the headers group.
1543 * It is not yet because we do not want to have a 16 bit hole
1544 */
1545 new->queue_mapping = old->queue_mapping;
1546
1547 memcpy(&new->headers, &old->headers, sizeof(new->headers));
1548 CHECK_SKB_FIELD(protocol);
1549 CHECK_SKB_FIELD(csum);
1550 CHECK_SKB_FIELD(hash);
1551 CHECK_SKB_FIELD(priority);
1552 CHECK_SKB_FIELD(skb_iif);
1553 CHECK_SKB_FIELD(vlan_proto);
1554 CHECK_SKB_FIELD(vlan_tci);
1555 CHECK_SKB_FIELD(transport_header);
1556 CHECK_SKB_FIELD(network_header);
1557 CHECK_SKB_FIELD(mac_header);
1558 CHECK_SKB_FIELD(inner_protocol);
1559 CHECK_SKB_FIELD(inner_transport_header);
1560 CHECK_SKB_FIELD(inner_network_header);
1561 CHECK_SKB_FIELD(inner_mac_header);
1562 CHECK_SKB_FIELD(mark);
1563#ifdef CONFIG_NETWORK_SECMARK
1564 CHECK_SKB_FIELD(secmark);
1565#endif
1566#ifdef CONFIG_NET_RX_BUSY_POLL
1567 CHECK_SKB_FIELD(napi_id);
1568#endif
1569 CHECK_SKB_FIELD(alloc_cpu);
1570#ifdef CONFIG_XPS
1571 CHECK_SKB_FIELD(sender_cpu);
1572#endif
1573#ifdef CONFIG_NET_SCHED
1574 CHECK_SKB_FIELD(tc_index);
1575#endif
1576
1577}
1578
1579/*
1580 * You should not add any new code to this function. Add it to
1581 * __copy_skb_header above instead.
1582 */
1583static struct sk_buff *__skb_clone(struct sk_buff *n, struct sk_buff *skb)
1584{
1585#define C(x) n->x = skb->x
1586
1587 n->next = n->prev = NULL;
1588 n->sk = NULL;
1589 __copy_skb_header(n, skb);
1590
1591 C(len);
1592 C(data_len);
1593 C(mac_len);
1594 n->hdr_len = skb->nohdr ? skb_headroom(skb) : skb->hdr_len;
1595 n->cloned = 1;
1596 n->nohdr = 0;
1597 n->peeked = 0;
1598 C(pfmemalloc);
1599 C(pp_recycle);
1600 n->destructor = NULL;
1601 C(tail);
1602 C(end);
1603 C(head);
1604 C(head_frag);
1605 C(data);
1606 C(truesize);
1607 refcount_set(&n->users, 1);
1608
1609 atomic_inc(&(skb_shinfo(skb)->dataref));
1610 skb->cloned = 1;
1611
1612 return n;
1613#undef C
1614}
1615
1616/**
1617 * alloc_skb_for_msg() - allocate sk_buff to wrap frag list forming a msg
1618 * @first: first sk_buff of the msg
1619 */
1620struct sk_buff *alloc_skb_for_msg(struct sk_buff *first)
1621{
1622 struct sk_buff *n;
1623
1624 n = alloc_skb(0, GFP_ATOMIC);
1625 if (!n)
1626 return NULL;
1627
1628 n->len = first->len;
1629 n->data_len = first->len;
1630 n->truesize = first->truesize;
1631
1632 skb_shinfo(n)->frag_list = first;
1633
1634 __copy_skb_header(n, first);
1635 n->destructor = NULL;
1636
1637 return n;
1638}
1639EXPORT_SYMBOL_GPL(alloc_skb_for_msg);
1640
1641/**
1642 * skb_morph - morph one skb into another
1643 * @dst: the skb to receive the contents
1644 * @src: the skb to supply the contents
1645 *
1646 * This is identical to skb_clone except that the target skb is
1647 * supplied by the user.
1648 *
1649 * The target skb is returned upon exit.
1650 */
1651struct sk_buff *skb_morph(struct sk_buff *dst, struct sk_buff *src)
1652{
1653 skb_release_all(dst, SKB_CONSUMED);
1654 return __skb_clone(dst, src);
1655}
1656EXPORT_SYMBOL_GPL(skb_morph);
1657
1658int mm_account_pinned_pages(struct mmpin *mmp, size_t size)
1659{
1660 unsigned long max_pg, num_pg, new_pg, old_pg, rlim;
1661 struct user_struct *user;
1662
1663 if (capable(CAP_IPC_LOCK) || !size)
1664 return 0;
1665
1666 rlim = rlimit(RLIMIT_MEMLOCK);
1667 if (rlim == RLIM_INFINITY)
1668 return 0;
1669
1670 num_pg = (size >> PAGE_SHIFT) + 2; /* worst case */
1671 max_pg = rlim >> PAGE_SHIFT;
1672 user = mmp->user ? : current_user();
1673
1674 old_pg = atomic_long_read(&user->locked_vm);
1675 do {
1676 new_pg = old_pg + num_pg;
1677 if (new_pg > max_pg)
1678 return -ENOBUFS;
1679 } while (!atomic_long_try_cmpxchg(&user->locked_vm, &old_pg, new_pg));
1680
1681 if (!mmp->user) {
1682 mmp->user = get_uid(user);
1683 mmp->num_pg = num_pg;
1684 } else {
1685 mmp->num_pg += num_pg;
1686 }
1687
1688 return 0;
1689}
1690EXPORT_SYMBOL_GPL(mm_account_pinned_pages);
1691
1692void mm_unaccount_pinned_pages(struct mmpin *mmp)
1693{
1694 if (mmp->user) {
1695 atomic_long_sub(mmp->num_pg, &mmp->user->locked_vm);
1696 free_uid(mmp->user);
1697 }
1698}
1699EXPORT_SYMBOL_GPL(mm_unaccount_pinned_pages);
1700
1701static struct ubuf_info *msg_zerocopy_alloc(struct sock *sk, size_t size)
1702{
1703 struct ubuf_info_msgzc *uarg;
1704 struct sk_buff *skb;
1705
1706 WARN_ON_ONCE(!in_task());
1707
1708 skb = sock_omalloc(sk, 0, GFP_KERNEL);
1709 if (!skb)
1710 return NULL;
1711
1712 BUILD_BUG_ON(sizeof(*uarg) > sizeof(skb->cb));
1713 uarg = (void *)skb->cb;
1714 uarg->mmp.user = NULL;
1715
1716 if (mm_account_pinned_pages(&uarg->mmp, size)) {
1717 kfree_skb(skb);
1718 return NULL;
1719 }
1720
1721 uarg->ubuf.ops = &msg_zerocopy_ubuf_ops;
1722 uarg->id = ((u32)atomic_inc_return(&sk->sk_zckey)) - 1;
1723 uarg->len = 1;
1724 uarg->bytelen = size;
1725 uarg->zerocopy = 1;
1726 uarg->ubuf.flags = SKBFL_ZEROCOPY_FRAG | SKBFL_DONT_ORPHAN;
1727 refcount_set(&uarg->ubuf.refcnt, 1);
1728 sock_hold(sk);
1729
1730 return &uarg->ubuf;
1731}
1732
1733static inline struct sk_buff *skb_from_uarg(struct ubuf_info_msgzc *uarg)
1734{
1735 return container_of((void *)uarg, struct sk_buff, cb);
1736}
1737
1738struct ubuf_info *msg_zerocopy_realloc(struct sock *sk, size_t size,
1739 struct ubuf_info *uarg)
1740{
1741 if (uarg) {
1742 struct ubuf_info_msgzc *uarg_zc;
1743 const u32 byte_limit = 1 << 19; /* limit to a few TSO */
1744 u32 bytelen, next;
1745
1746 /* there might be non MSG_ZEROCOPY users */
1747 if (uarg->ops != &msg_zerocopy_ubuf_ops)
1748 return NULL;
1749
1750 /* realloc only when socket is locked (TCP, UDP cork),
1751 * so uarg->len and sk_zckey access is serialized
1752 */
1753 if (!sock_owned_by_user(sk)) {
1754 WARN_ON_ONCE(1);
1755 return NULL;
1756 }
1757
1758 uarg_zc = uarg_to_msgzc(uarg);
1759 bytelen = uarg_zc->bytelen + size;
1760 if (uarg_zc->len == USHRT_MAX - 1 || bytelen > byte_limit) {
1761 /* TCP can create new skb to attach new uarg */
1762 if (sk->sk_type == SOCK_STREAM)
1763 goto new_alloc;
1764 return NULL;
1765 }
1766
1767 next = (u32)atomic_read(&sk->sk_zckey);
1768 if ((u32)(uarg_zc->id + uarg_zc->len) == next) {
1769 if (mm_account_pinned_pages(&uarg_zc->mmp, size))
1770 return NULL;
1771 uarg_zc->len++;
1772 uarg_zc->bytelen = bytelen;
1773 atomic_set(&sk->sk_zckey, ++next);
1774
1775 /* no extra ref when appending to datagram (MSG_MORE) */
1776 if (sk->sk_type == SOCK_STREAM)
1777 net_zcopy_get(uarg);
1778
1779 return uarg;
1780 }
1781 }
1782
1783new_alloc:
1784 return msg_zerocopy_alloc(sk, size);
1785}
1786EXPORT_SYMBOL_GPL(msg_zerocopy_realloc);
1787
1788static bool skb_zerocopy_notify_extend(struct sk_buff *skb, u32 lo, u16 len)
1789{
1790 struct sock_exterr_skb *serr = SKB_EXT_ERR(skb);
1791 u32 old_lo, old_hi;
1792 u64 sum_len;
1793
1794 old_lo = serr->ee.ee_info;
1795 old_hi = serr->ee.ee_data;
1796 sum_len = old_hi - old_lo + 1ULL + len;
1797
1798 if (sum_len >= (1ULL << 32))
1799 return false;
1800
1801 if (lo != old_hi + 1)
1802 return false;
1803
1804 serr->ee.ee_data += len;
1805 return true;
1806}
1807
1808static void __msg_zerocopy_callback(struct ubuf_info_msgzc *uarg)
1809{
1810 struct sk_buff *tail, *skb = skb_from_uarg(uarg);
1811 struct sock_exterr_skb *serr;
1812 struct sock *sk = skb->sk;
1813 struct sk_buff_head *q;
1814 unsigned long flags;
1815 bool is_zerocopy;
1816 u32 lo, hi;
1817 u16 len;
1818
1819 mm_unaccount_pinned_pages(&uarg->mmp);
1820
1821 /* if !len, there was only 1 call, and it was aborted
1822 * so do not queue a completion notification
1823 */
1824 if (!uarg->len || sock_flag(sk, SOCK_DEAD))
1825 goto release;
1826
1827 len = uarg->len;
1828 lo = uarg->id;
1829 hi = uarg->id + len - 1;
1830 is_zerocopy = uarg->zerocopy;
1831
1832 serr = SKB_EXT_ERR(skb);
1833 memset(serr, 0, sizeof(*serr));
1834 serr->ee.ee_errno = 0;
1835 serr->ee.ee_origin = SO_EE_ORIGIN_ZEROCOPY;
1836 serr->ee.ee_data = hi;
1837 serr->ee.ee_info = lo;
1838 if (!is_zerocopy)
1839 serr->ee.ee_code |= SO_EE_CODE_ZEROCOPY_COPIED;
1840
1841 q = &sk->sk_error_queue;
1842 spin_lock_irqsave(&q->lock, flags);
1843 tail = skb_peek_tail(q);
1844 if (!tail || SKB_EXT_ERR(tail)->ee.ee_origin != SO_EE_ORIGIN_ZEROCOPY ||
1845 !skb_zerocopy_notify_extend(tail, lo, len)) {
1846 __skb_queue_tail(q, skb);
1847 skb = NULL;
1848 }
1849 spin_unlock_irqrestore(&q->lock, flags);
1850
1851 sk_error_report(sk);
1852
1853release:
1854 consume_skb(skb);
1855 sock_put(sk);
1856}
1857
1858static void msg_zerocopy_complete(struct sk_buff *skb, struct ubuf_info *uarg,
1859 bool success)
1860{
1861 struct ubuf_info_msgzc *uarg_zc = uarg_to_msgzc(uarg);
1862
1863 uarg_zc->zerocopy = uarg_zc->zerocopy & success;
1864
1865 if (refcount_dec_and_test(&uarg->refcnt))
1866 __msg_zerocopy_callback(uarg_zc);
1867}
1868
1869void msg_zerocopy_put_abort(struct ubuf_info *uarg, bool have_uref)
1870{
1871 struct sock *sk = skb_from_uarg(uarg_to_msgzc(uarg))->sk;
1872
1873 atomic_dec(&sk->sk_zckey);
1874 uarg_to_msgzc(uarg)->len--;
1875
1876 if (have_uref)
1877 msg_zerocopy_complete(NULL, uarg, true);
1878}
1879EXPORT_SYMBOL_GPL(msg_zerocopy_put_abort);
1880
1881const struct ubuf_info_ops msg_zerocopy_ubuf_ops = {
1882 .complete = msg_zerocopy_complete,
1883};
1884EXPORT_SYMBOL_GPL(msg_zerocopy_ubuf_ops);
1885
1886int skb_zerocopy_iter_stream(struct sock *sk, struct sk_buff *skb,
1887 struct msghdr *msg, int len,
1888 struct ubuf_info *uarg)
1889{
1890 int err, orig_len = skb->len;
1891
1892 if (uarg->ops->link_skb) {
1893 err = uarg->ops->link_skb(skb, uarg);
1894 if (err)
1895 return err;
1896 } else {
1897 struct ubuf_info *orig_uarg = skb_zcopy(skb);
1898
1899 /* An skb can only point to one uarg. This edge case happens
1900 * when TCP appends to an skb, but zerocopy_realloc triggered
1901 * a new alloc.
1902 */
1903 if (orig_uarg && uarg != orig_uarg)
1904 return -EEXIST;
1905 }
1906
1907 err = __zerocopy_sg_from_iter(msg, sk, skb, &msg->msg_iter, len);
1908 if (err == -EFAULT || (err == -EMSGSIZE && skb->len == orig_len)) {
1909 struct sock *save_sk = skb->sk;
1910
1911 /* Streams do not free skb on error. Reset to prev state. */
1912 iov_iter_revert(&msg->msg_iter, skb->len - orig_len);
1913 skb->sk = sk;
1914 ___pskb_trim(skb, orig_len);
1915 skb->sk = save_sk;
1916 return err;
1917 }
1918
1919 skb_zcopy_set(skb, uarg, NULL);
1920 return skb->len - orig_len;
1921}
1922EXPORT_SYMBOL_GPL(skb_zerocopy_iter_stream);
1923
1924void __skb_zcopy_downgrade_managed(struct sk_buff *skb)
1925{
1926 int i;
1927
1928 skb_shinfo(skb)->flags &= ~SKBFL_MANAGED_FRAG_REFS;
1929 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
1930 skb_frag_ref(skb, i);
1931}
1932EXPORT_SYMBOL_GPL(__skb_zcopy_downgrade_managed);
1933
1934static int skb_zerocopy_clone(struct sk_buff *nskb, struct sk_buff *orig,
1935 gfp_t gfp_mask)
1936{
1937 if (skb_zcopy(orig)) {
1938 if (skb_zcopy(nskb)) {
1939 /* !gfp_mask callers are verified to !skb_zcopy(nskb) */
1940 if (!gfp_mask) {
1941 WARN_ON_ONCE(1);
1942 return -ENOMEM;
1943 }
1944 if (skb_uarg(nskb) == skb_uarg(orig))
1945 return 0;
1946 if (skb_copy_ubufs(nskb, GFP_ATOMIC))
1947 return -EIO;
1948 }
1949 skb_zcopy_set(nskb, skb_uarg(orig), NULL);
1950 }
1951 return 0;
1952}
1953
1954/**
1955 * skb_copy_ubufs - copy userspace skb frags buffers to kernel
1956 * @skb: the skb to modify
1957 * @gfp_mask: allocation priority
1958 *
1959 * This must be called on skb with SKBFL_ZEROCOPY_ENABLE.
1960 * It will copy all frags into kernel and drop the reference
1961 * to userspace pages.
1962 *
1963 * If this function is called from an interrupt gfp_mask() must be
1964 * %GFP_ATOMIC.
1965 *
1966 * Returns 0 on success or a negative error code on failure
1967 * to allocate kernel memory to copy to.
1968 */
1969int skb_copy_ubufs(struct sk_buff *skb, gfp_t gfp_mask)
1970{
1971 int num_frags = skb_shinfo(skb)->nr_frags;
1972 struct page *page, *head = NULL;
1973 int i, order, psize, new_frags;
1974 u32 d_off;
1975
1976 if (skb_shared(skb) || skb_unclone(skb, gfp_mask))
1977 return -EINVAL;
1978
1979 if (!skb_frags_readable(skb))
1980 return -EFAULT;
1981
1982 if (!num_frags)
1983 goto release;
1984
1985 /* We might have to allocate high order pages, so compute what minimum
1986 * page order is needed.
1987 */
1988 order = 0;
1989 while ((PAGE_SIZE << order) * MAX_SKB_FRAGS < __skb_pagelen(skb))
1990 order++;
1991 psize = (PAGE_SIZE << order);
1992
1993 new_frags = (__skb_pagelen(skb) + psize - 1) >> (PAGE_SHIFT + order);
1994 for (i = 0; i < new_frags; i++) {
1995 page = alloc_pages(gfp_mask | __GFP_COMP, order);
1996 if (!page) {
1997 while (head) {
1998 struct page *next = (struct page *)page_private(head);
1999 put_page(head);
2000 head = next;
2001 }
2002 return -ENOMEM;
2003 }
2004 set_page_private(page, (unsigned long)head);
2005 head = page;
2006 }
2007
2008 page = head;
2009 d_off = 0;
2010 for (i = 0; i < num_frags; i++) {
2011 skb_frag_t *f = &skb_shinfo(skb)->frags[i];
2012 u32 p_off, p_len, copied;
2013 struct page *p;
2014 u8 *vaddr;
2015
2016 skb_frag_foreach_page(f, skb_frag_off(f), skb_frag_size(f),
2017 p, p_off, p_len, copied) {
2018 u32 copy, done = 0;
2019 vaddr = kmap_atomic(p);
2020
2021 while (done < p_len) {
2022 if (d_off == psize) {
2023 d_off = 0;
2024 page = (struct page *)page_private(page);
2025 }
2026 copy = min_t(u32, psize - d_off, p_len - done);
2027 memcpy(page_address(page) + d_off,
2028 vaddr + p_off + done, copy);
2029 done += copy;
2030 d_off += copy;
2031 }
2032 kunmap_atomic(vaddr);
2033 }
2034 }
2035
2036 /* skb frags release userspace buffers */
2037 for (i = 0; i < num_frags; i++)
2038 skb_frag_unref(skb, i);
2039
2040 /* skb frags point to kernel buffers */
2041 for (i = 0; i < new_frags - 1; i++) {
2042 __skb_fill_netmem_desc(skb, i, page_to_netmem(head), 0, psize);
2043 head = (struct page *)page_private(head);
2044 }
2045 __skb_fill_netmem_desc(skb, new_frags - 1, page_to_netmem(head), 0,
2046 d_off);
2047 skb_shinfo(skb)->nr_frags = new_frags;
2048
2049release:
2050 skb_zcopy_clear(skb, false);
2051 return 0;
2052}
2053EXPORT_SYMBOL_GPL(skb_copy_ubufs);
2054
2055/**
2056 * skb_clone - duplicate an sk_buff
2057 * @skb: buffer to clone
2058 * @gfp_mask: allocation priority
2059 *
2060 * Duplicate an &sk_buff. The new one is not owned by a socket. Both
2061 * copies share the same packet data but not structure. The new
2062 * buffer has a reference count of 1. If the allocation fails the
2063 * function returns %NULL otherwise the new buffer is returned.
2064 *
2065 * If this function is called from an interrupt gfp_mask() must be
2066 * %GFP_ATOMIC.
2067 */
2068
2069struct sk_buff *skb_clone(struct sk_buff *skb, gfp_t gfp_mask)
2070{
2071 struct sk_buff_fclones *fclones = container_of(skb,
2072 struct sk_buff_fclones,
2073 skb1);
2074 struct sk_buff *n;
2075
2076 if (skb_orphan_frags(skb, gfp_mask))
2077 return NULL;
2078
2079 if (skb->fclone == SKB_FCLONE_ORIG &&
2080 refcount_read(&fclones->fclone_ref) == 1) {
2081 n = &fclones->skb2;
2082 refcount_set(&fclones->fclone_ref, 2);
2083 n->fclone = SKB_FCLONE_CLONE;
2084 } else {
2085 if (skb_pfmemalloc(skb))
2086 gfp_mask |= __GFP_MEMALLOC;
2087
2088 n = kmem_cache_alloc(net_hotdata.skbuff_cache, gfp_mask);
2089 if (!n)
2090 return NULL;
2091
2092 n->fclone = SKB_FCLONE_UNAVAILABLE;
2093 }
2094
2095 return __skb_clone(n, skb);
2096}
2097EXPORT_SYMBOL(skb_clone);
2098
2099void skb_headers_offset_update(struct sk_buff *skb, int off)
2100{
2101 /* Only adjust this if it actually is csum_start rather than csum */
2102 if (skb->ip_summed == CHECKSUM_PARTIAL)
2103 skb->csum_start += off;
2104 /* {transport,network,mac}_header and tail are relative to skb->head */
2105 skb->transport_header += off;
2106 skb->network_header += off;
2107 if (skb_mac_header_was_set(skb))
2108 skb->mac_header += off;
2109 skb->inner_transport_header += off;
2110 skb->inner_network_header += off;
2111 skb->inner_mac_header += off;
2112}
2113EXPORT_SYMBOL(skb_headers_offset_update);
2114
2115void skb_copy_header(struct sk_buff *new, const struct sk_buff *old)
2116{
2117 __copy_skb_header(new, old);
2118
2119 skb_shinfo(new)->gso_size = skb_shinfo(old)->gso_size;
2120 skb_shinfo(new)->gso_segs = skb_shinfo(old)->gso_segs;
2121 skb_shinfo(new)->gso_type = skb_shinfo(old)->gso_type;
2122}
2123EXPORT_SYMBOL(skb_copy_header);
2124
2125static inline int skb_alloc_rx_flag(const struct sk_buff *skb)
2126{
2127 if (skb_pfmemalloc(skb))
2128 return SKB_ALLOC_RX;
2129 return 0;
2130}
2131
2132/**
2133 * skb_copy - create private copy of an sk_buff
2134 * @skb: buffer to copy
2135 * @gfp_mask: allocation priority
2136 *
2137 * Make a copy of both an &sk_buff and its data. This is used when the
2138 * caller wishes to modify the data and needs a private copy of the
2139 * data to alter. Returns %NULL on failure or the pointer to the buffer
2140 * on success. The returned buffer has a reference count of 1.
2141 *
2142 * As by-product this function converts non-linear &sk_buff to linear
2143 * one, so that &sk_buff becomes completely private and caller is allowed
2144 * to modify all the data of returned buffer. This means that this
2145 * function is not recommended for use in circumstances when only
2146 * header is going to be modified. Use pskb_copy() instead.
2147 */
2148
2149struct sk_buff *skb_copy(const struct sk_buff *skb, gfp_t gfp_mask)
2150{
2151 struct sk_buff *n;
2152 unsigned int size;
2153 int headerlen;
2154
2155 if (!skb_frags_readable(skb))
2156 return NULL;
2157
2158 if (WARN_ON_ONCE(skb_shinfo(skb)->gso_type & SKB_GSO_FRAGLIST))
2159 return NULL;
2160
2161 headerlen = skb_headroom(skb);
2162 size = skb_end_offset(skb) + skb->data_len;
2163 n = __alloc_skb(size, gfp_mask,
2164 skb_alloc_rx_flag(skb), NUMA_NO_NODE);
2165 if (!n)
2166 return NULL;
2167
2168 /* Set the data pointer */
2169 skb_reserve(n, headerlen);
2170 /* Set the tail pointer and length */
2171 skb_put(n, skb->len);
2172
2173 BUG_ON(skb_copy_bits(skb, -headerlen, n->head, headerlen + skb->len));
2174
2175 skb_copy_header(n, skb);
2176 return n;
2177}
2178EXPORT_SYMBOL(skb_copy);
2179
2180/**
2181 * __pskb_copy_fclone - create copy of an sk_buff with private head.
2182 * @skb: buffer to copy
2183 * @headroom: headroom of new skb
2184 * @gfp_mask: allocation priority
2185 * @fclone: if true allocate the copy of the skb from the fclone
2186 * cache instead of the head cache; it is recommended to set this
2187 * to true for the cases where the copy will likely be cloned
2188 *
2189 * Make a copy of both an &sk_buff and part of its data, located
2190 * in header. Fragmented data remain shared. This is used when
2191 * the caller wishes to modify only header of &sk_buff and needs
2192 * private copy of the header to alter. Returns %NULL on failure
2193 * or the pointer to the buffer on success.
2194 * The returned buffer has a reference count of 1.
2195 */
2196
2197struct sk_buff *__pskb_copy_fclone(struct sk_buff *skb, int headroom,
2198 gfp_t gfp_mask, bool fclone)
2199{
2200 unsigned int size = skb_headlen(skb) + headroom;
2201 int flags = skb_alloc_rx_flag(skb) | (fclone ? SKB_ALLOC_FCLONE : 0);
2202 struct sk_buff *n = __alloc_skb(size, gfp_mask, flags, NUMA_NO_NODE);
2203
2204 if (!n)
2205 goto out;
2206
2207 /* Set the data pointer */
2208 skb_reserve(n, headroom);
2209 /* Set the tail pointer and length */
2210 skb_put(n, skb_headlen(skb));
2211 /* Copy the bytes */
2212 skb_copy_from_linear_data(skb, n->data, n->len);
2213
2214 n->truesize += skb->data_len;
2215 n->data_len = skb->data_len;
2216 n->len = skb->len;
2217
2218 if (skb_shinfo(skb)->nr_frags) {
2219 int i;
2220
2221 if (skb_orphan_frags(skb, gfp_mask) ||
2222 skb_zerocopy_clone(n, skb, gfp_mask)) {
2223 kfree_skb(n);
2224 n = NULL;
2225 goto out;
2226 }
2227 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
2228 skb_shinfo(n)->frags[i] = skb_shinfo(skb)->frags[i];
2229 skb_frag_ref(skb, i);
2230 }
2231 skb_shinfo(n)->nr_frags = i;
2232 }
2233
2234 if (skb_has_frag_list(skb)) {
2235 skb_shinfo(n)->frag_list = skb_shinfo(skb)->frag_list;
2236 skb_clone_fraglist(n);
2237 }
2238
2239 skb_copy_header(n, skb);
2240out:
2241 return n;
2242}
2243EXPORT_SYMBOL(__pskb_copy_fclone);
2244
2245/**
2246 * pskb_expand_head - reallocate header of &sk_buff
2247 * @skb: buffer to reallocate
2248 * @nhead: room to add at head
2249 * @ntail: room to add at tail
2250 * @gfp_mask: allocation priority
2251 *
2252 * Expands (or creates identical copy, if @nhead and @ntail are zero)
2253 * header of @skb. &sk_buff itself is not changed. &sk_buff MUST have
2254 * reference count of 1. Returns zero in the case of success or error,
2255 * if expansion failed. In the last case, &sk_buff is not changed.
2256 *
2257 * All the pointers pointing into skb header may change and must be
2258 * reloaded after call to this function.
2259 */
2260
2261int pskb_expand_head(struct sk_buff *skb, int nhead, int ntail,
2262 gfp_t gfp_mask)
2263{
2264 unsigned int osize = skb_end_offset(skb);
2265 unsigned int size = osize + nhead + ntail;
2266 long off;
2267 u8 *data;
2268 int i;
2269
2270 BUG_ON(nhead < 0);
2271
2272 BUG_ON(skb_shared(skb));
2273
2274 skb_zcopy_downgrade_managed(skb);
2275
2276 if (skb_pfmemalloc(skb))
2277 gfp_mask |= __GFP_MEMALLOC;
2278
2279 data = kmalloc_reserve(&size, gfp_mask, NUMA_NO_NODE, NULL);
2280 if (!data)
2281 goto nodata;
2282 size = SKB_WITH_OVERHEAD(size);
2283
2284 /* Copy only real data... and, alas, header. This should be
2285 * optimized for the cases when header is void.
2286 */
2287 memcpy(data + nhead, skb->head, skb_tail_pointer(skb) - skb->head);
2288
2289 memcpy((struct skb_shared_info *)(data + size),
2290 skb_shinfo(skb),
2291 offsetof(struct skb_shared_info, frags[skb_shinfo(skb)->nr_frags]));
2292
2293 /*
2294 * if shinfo is shared we must drop the old head gracefully, but if it
2295 * is not we can just drop the old head and let the existing refcount
2296 * be since all we did is relocate the values
2297 */
2298 if (skb_cloned(skb)) {
2299 if (skb_orphan_frags(skb, gfp_mask))
2300 goto nofrags;
2301 if (skb_zcopy(skb))
2302 refcount_inc(&skb_uarg(skb)->refcnt);
2303 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
2304 skb_frag_ref(skb, i);
2305
2306 if (skb_has_frag_list(skb))
2307 skb_clone_fraglist(skb);
2308
2309 skb_release_data(skb, SKB_CONSUMED);
2310 } else {
2311 skb_free_head(skb);
2312 }
2313 off = (data + nhead) - skb->head;
2314
2315 skb->head = data;
2316 skb->head_frag = 0;
2317 skb->data += off;
2318
2319 skb_set_end_offset(skb, size);
2320#ifdef NET_SKBUFF_DATA_USES_OFFSET
2321 off = nhead;
2322#endif
2323 skb->tail += off;
2324 skb_headers_offset_update(skb, nhead);
2325 skb->cloned = 0;
2326 skb->hdr_len = 0;
2327 skb->nohdr = 0;
2328 atomic_set(&skb_shinfo(skb)->dataref, 1);
2329
2330 skb_metadata_clear(skb);
2331
2332 /* It is not generally safe to change skb->truesize.
2333 * For the moment, we really care of rx path, or
2334 * when skb is orphaned (not attached to a socket).
2335 */
2336 if (!skb->sk || skb->destructor == sock_edemux)
2337 skb->truesize += size - osize;
2338
2339 return 0;
2340
2341nofrags:
2342 skb_kfree_head(data, size);
2343nodata:
2344 return -ENOMEM;
2345}
2346EXPORT_SYMBOL(pskb_expand_head);
2347
2348/* Make private copy of skb with writable head and some headroom */
2349
2350struct sk_buff *skb_realloc_headroom(struct sk_buff *skb, unsigned int headroom)
2351{
2352 struct sk_buff *skb2;
2353 int delta = headroom - skb_headroom(skb);
2354
2355 if (delta <= 0)
2356 skb2 = pskb_copy(skb, GFP_ATOMIC);
2357 else {
2358 skb2 = skb_clone(skb, GFP_ATOMIC);
2359 if (skb2 && pskb_expand_head(skb2, SKB_DATA_ALIGN(delta), 0,
2360 GFP_ATOMIC)) {
2361 kfree_skb(skb2);
2362 skb2 = NULL;
2363 }
2364 }
2365 return skb2;
2366}
2367EXPORT_SYMBOL(skb_realloc_headroom);
2368
2369/* Note: We plan to rework this in linux-6.4 */
2370int __skb_unclone_keeptruesize(struct sk_buff *skb, gfp_t pri)
2371{
2372 unsigned int saved_end_offset, saved_truesize;
2373 struct skb_shared_info *shinfo;
2374 int res;
2375
2376 saved_end_offset = skb_end_offset(skb);
2377 saved_truesize = skb->truesize;
2378
2379 res = pskb_expand_head(skb, 0, 0, pri);
2380 if (res)
2381 return res;
2382
2383 skb->truesize = saved_truesize;
2384
2385 if (likely(skb_end_offset(skb) == saved_end_offset))
2386 return 0;
2387
2388 /* We can not change skb->end if the original or new value
2389 * is SKB_SMALL_HEAD_HEADROOM, as it might break skb_kfree_head().
2390 */
2391 if (saved_end_offset == SKB_SMALL_HEAD_HEADROOM ||
2392 skb_end_offset(skb) == SKB_SMALL_HEAD_HEADROOM) {
2393 /* We think this path should not be taken.
2394 * Add a temporary trace to warn us just in case.
2395 */
2396 pr_err_once("__skb_unclone_keeptruesize() skb_end_offset() %u -> %u\n",
2397 saved_end_offset, skb_end_offset(skb));
2398 WARN_ON_ONCE(1);
2399 return 0;
2400 }
2401
2402 shinfo = skb_shinfo(skb);
2403
2404 /* We are about to change back skb->end,
2405 * we need to move skb_shinfo() to its new location.
2406 */
2407 memmove(skb->head + saved_end_offset,
2408 shinfo,
2409 offsetof(struct skb_shared_info, frags[shinfo->nr_frags]));
2410
2411 skb_set_end_offset(skb, saved_end_offset);
2412
2413 return 0;
2414}
2415
2416/**
2417 * skb_expand_head - reallocate header of &sk_buff
2418 * @skb: buffer to reallocate
2419 * @headroom: needed headroom
2420 *
2421 * Unlike skb_realloc_headroom, this one does not allocate a new skb
2422 * if possible; copies skb->sk to new skb as needed
2423 * and frees original skb in case of failures.
2424 *
2425 * It expect increased headroom and generates warning otherwise.
2426 */
2427
2428struct sk_buff *skb_expand_head(struct sk_buff *skb, unsigned int headroom)
2429{
2430 int delta = headroom - skb_headroom(skb);
2431 int osize = skb_end_offset(skb);
2432 struct sock *sk = skb->sk;
2433
2434 if (WARN_ONCE(delta <= 0,
2435 "%s is expecting an increase in the headroom", __func__))
2436 return skb;
2437
2438 delta = SKB_DATA_ALIGN(delta);
2439 /* pskb_expand_head() might crash, if skb is shared. */
2440 if (skb_shared(skb) || !is_skb_wmem(skb)) {
2441 struct sk_buff *nskb = skb_clone(skb, GFP_ATOMIC);
2442
2443 if (unlikely(!nskb))
2444 goto fail;
2445
2446 if (sk)
2447 skb_set_owner_w(nskb, sk);
2448 consume_skb(skb);
2449 skb = nskb;
2450 }
2451 if (pskb_expand_head(skb, delta, 0, GFP_ATOMIC))
2452 goto fail;
2453
2454 if (sk && is_skb_wmem(skb)) {
2455 delta = skb_end_offset(skb) - osize;
2456 refcount_add(delta, &sk->sk_wmem_alloc);
2457 skb->truesize += delta;
2458 }
2459 return skb;
2460
2461fail:
2462 kfree_skb(skb);
2463 return NULL;
2464}
2465EXPORT_SYMBOL(skb_expand_head);
2466
2467/**
2468 * skb_copy_expand - copy and expand sk_buff
2469 * @skb: buffer to copy
2470 * @newheadroom: new free bytes at head
2471 * @newtailroom: new free bytes at tail
2472 * @gfp_mask: allocation priority
2473 *
2474 * Make a copy of both an &sk_buff and its data and while doing so
2475 * allocate additional space.
2476 *
2477 * This is used when the caller wishes to modify the data and needs a
2478 * private copy of the data to alter as well as more space for new fields.
2479 * Returns %NULL on failure or the pointer to the buffer
2480 * on success. The returned buffer has a reference count of 1.
2481 *
2482 * You must pass %GFP_ATOMIC as the allocation priority if this function
2483 * is called from an interrupt.
2484 */
2485struct sk_buff *skb_copy_expand(const struct sk_buff *skb,
2486 int newheadroom, int newtailroom,
2487 gfp_t gfp_mask)
2488{
2489 /*
2490 * Allocate the copy buffer
2491 */
2492 int head_copy_len, head_copy_off;
2493 struct sk_buff *n;
2494 int oldheadroom;
2495
2496 if (!skb_frags_readable(skb))
2497 return NULL;
2498
2499 if (WARN_ON_ONCE(skb_shinfo(skb)->gso_type & SKB_GSO_FRAGLIST))
2500 return NULL;
2501
2502 oldheadroom = skb_headroom(skb);
2503 n = __alloc_skb(newheadroom + skb->len + newtailroom,
2504 gfp_mask, skb_alloc_rx_flag(skb),
2505 NUMA_NO_NODE);
2506 if (!n)
2507 return NULL;
2508
2509 skb_reserve(n, newheadroom);
2510
2511 /* Set the tail pointer and length */
2512 skb_put(n, skb->len);
2513
2514 head_copy_len = oldheadroom;
2515 head_copy_off = 0;
2516 if (newheadroom <= head_copy_len)
2517 head_copy_len = newheadroom;
2518 else
2519 head_copy_off = newheadroom - head_copy_len;
2520
2521 /* Copy the linear header and data. */
2522 BUG_ON(skb_copy_bits(skb, -head_copy_len, n->head + head_copy_off,
2523 skb->len + head_copy_len));
2524
2525 skb_copy_header(n, skb);
2526
2527 skb_headers_offset_update(n, newheadroom - oldheadroom);
2528
2529 return n;
2530}
2531EXPORT_SYMBOL(skb_copy_expand);
2532
2533/**
2534 * __skb_pad - zero pad the tail of an skb
2535 * @skb: buffer to pad
2536 * @pad: space to pad
2537 * @free_on_error: free buffer on error
2538 *
2539 * Ensure that a buffer is followed by a padding area that is zero
2540 * filled. Used by network drivers which may DMA or transfer data
2541 * beyond the buffer end onto the wire.
2542 *
2543 * May return error in out of memory cases. The skb is freed on error
2544 * if @free_on_error is true.
2545 */
2546
2547int __skb_pad(struct sk_buff *skb, int pad, bool free_on_error)
2548{
2549 int err;
2550 int ntail;
2551
2552 /* If the skbuff is non linear tailroom is always zero.. */
2553 if (!skb_cloned(skb) && skb_tailroom(skb) >= pad) {
2554 memset(skb->data+skb->len, 0, pad);
2555 return 0;
2556 }
2557
2558 ntail = skb->data_len + pad - (skb->end - skb->tail);
2559 if (likely(skb_cloned(skb) || ntail > 0)) {
2560 err = pskb_expand_head(skb, 0, ntail, GFP_ATOMIC);
2561 if (unlikely(err))
2562 goto free_skb;
2563 }
2564
2565 /* FIXME: The use of this function with non-linear skb's really needs
2566 * to be audited.
2567 */
2568 err = skb_linearize(skb);
2569 if (unlikely(err))
2570 goto free_skb;
2571
2572 memset(skb->data + skb->len, 0, pad);
2573 return 0;
2574
2575free_skb:
2576 if (free_on_error)
2577 kfree_skb(skb);
2578 return err;
2579}
2580EXPORT_SYMBOL(__skb_pad);
2581
2582/**
2583 * pskb_put - add data to the tail of a potentially fragmented buffer
2584 * @skb: start of the buffer to use
2585 * @tail: tail fragment of the buffer to use
2586 * @len: amount of data to add
2587 *
2588 * This function extends the used data area of the potentially
2589 * fragmented buffer. @tail must be the last fragment of @skb -- or
2590 * @skb itself. If this would exceed the total buffer size the kernel
2591 * will panic. A pointer to the first byte of the extra data is
2592 * returned.
2593 */
2594
2595void *pskb_put(struct sk_buff *skb, struct sk_buff *tail, int len)
2596{
2597 if (tail != skb) {
2598 skb->data_len += len;
2599 skb->len += len;
2600 }
2601 return skb_put(tail, len);
2602}
2603EXPORT_SYMBOL_GPL(pskb_put);
2604
2605/**
2606 * skb_put - add data to a buffer
2607 * @skb: buffer to use
2608 * @len: amount of data to add
2609 *
2610 * This function extends the used data area of the buffer. If this would
2611 * exceed the total buffer size the kernel will panic. A pointer to the
2612 * first byte of the extra data is returned.
2613 */
2614void *skb_put(struct sk_buff *skb, unsigned int len)
2615{
2616 void *tmp = skb_tail_pointer(skb);
2617 SKB_LINEAR_ASSERT(skb);
2618 skb->tail += len;
2619 skb->len += len;
2620 if (unlikely(skb->tail > skb->end))
2621 skb_over_panic(skb, len, __builtin_return_address(0));
2622 return tmp;
2623}
2624EXPORT_SYMBOL(skb_put);
2625
2626/**
2627 * skb_push - add data to the start of a buffer
2628 * @skb: buffer to use
2629 * @len: amount of data to add
2630 *
2631 * This function extends the used data area of the buffer at the buffer
2632 * start. If this would exceed the total buffer headroom the kernel will
2633 * panic. A pointer to the first byte of the extra data is returned.
2634 */
2635void *skb_push(struct sk_buff *skb, unsigned int len)
2636{
2637 skb->data -= len;
2638 skb->len += len;
2639 if (unlikely(skb->data < skb->head))
2640 skb_under_panic(skb, len, __builtin_return_address(0));
2641 return skb->data;
2642}
2643EXPORT_SYMBOL(skb_push);
2644
2645/**
2646 * skb_pull - remove data from the start of a buffer
2647 * @skb: buffer to use
2648 * @len: amount of data to remove
2649 *
2650 * This function removes data from the start of a buffer, returning
2651 * the memory to the headroom. A pointer to the next data in the buffer
2652 * is returned. Once the data has been pulled future pushes will overwrite
2653 * the old data.
2654 */
2655void *skb_pull(struct sk_buff *skb, unsigned int len)
2656{
2657 return skb_pull_inline(skb, len);
2658}
2659EXPORT_SYMBOL(skb_pull);
2660
2661/**
2662 * skb_pull_data - remove data from the start of a buffer returning its
2663 * original position.
2664 * @skb: buffer to use
2665 * @len: amount of data to remove
2666 *
2667 * This function removes data from the start of a buffer, returning
2668 * the memory to the headroom. A pointer to the original data in the buffer
2669 * is returned after checking if there is enough data to pull. Once the
2670 * data has been pulled future pushes will overwrite the old data.
2671 */
2672void *skb_pull_data(struct sk_buff *skb, size_t len)
2673{
2674 void *data = skb->data;
2675
2676 if (skb->len < len)
2677 return NULL;
2678
2679 skb_pull(skb, len);
2680
2681 return data;
2682}
2683EXPORT_SYMBOL(skb_pull_data);
2684
2685/**
2686 * skb_trim - remove end from a buffer
2687 * @skb: buffer to alter
2688 * @len: new length
2689 *
2690 * Cut the length of a buffer down by removing data from the tail. If
2691 * the buffer is already under the length specified it is not modified.
2692 * The skb must be linear.
2693 */
2694void skb_trim(struct sk_buff *skb, unsigned int len)
2695{
2696 if (skb->len > len)
2697 __skb_trim(skb, len);
2698}
2699EXPORT_SYMBOL(skb_trim);
2700
2701/* Trims skb to length len. It can change skb pointers.
2702 */
2703
2704int ___pskb_trim(struct sk_buff *skb, unsigned int len)
2705{
2706 struct sk_buff **fragp;
2707 struct sk_buff *frag;
2708 int offset = skb_headlen(skb);
2709 int nfrags = skb_shinfo(skb)->nr_frags;
2710 int i;
2711 int err;
2712
2713 if (skb_cloned(skb) &&
2714 unlikely((err = pskb_expand_head(skb, 0, 0, GFP_ATOMIC))))
2715 return err;
2716
2717 i = 0;
2718 if (offset >= len)
2719 goto drop_pages;
2720
2721 for (; i < nfrags; i++) {
2722 int end = offset + skb_frag_size(&skb_shinfo(skb)->frags[i]);
2723
2724 if (end < len) {
2725 offset = end;
2726 continue;
2727 }
2728
2729 skb_frag_size_set(&skb_shinfo(skb)->frags[i++], len - offset);
2730
2731drop_pages:
2732 skb_shinfo(skb)->nr_frags = i;
2733
2734 for (; i < nfrags; i++)
2735 skb_frag_unref(skb, i);
2736
2737 if (skb_has_frag_list(skb))
2738 skb_drop_fraglist(skb);
2739 goto done;
2740 }
2741
2742 for (fragp = &skb_shinfo(skb)->frag_list; (frag = *fragp);
2743 fragp = &frag->next) {
2744 int end = offset + frag->len;
2745
2746 if (skb_shared(frag)) {
2747 struct sk_buff *nfrag;
2748
2749 nfrag = skb_clone(frag, GFP_ATOMIC);
2750 if (unlikely(!nfrag))
2751 return -ENOMEM;
2752
2753 nfrag->next = frag->next;
2754 consume_skb(frag);
2755 frag = nfrag;
2756 *fragp = frag;
2757 }
2758
2759 if (end < len) {
2760 offset = end;
2761 continue;
2762 }
2763
2764 if (end > len &&
2765 unlikely((err = pskb_trim(frag, len - offset))))
2766 return err;
2767
2768 if (frag->next)
2769 skb_drop_list(&frag->next);
2770 break;
2771 }
2772
2773done:
2774 if (len > skb_headlen(skb)) {
2775 skb->data_len -= skb->len - len;
2776 skb->len = len;
2777 } else {
2778 skb->len = len;
2779 skb->data_len = 0;
2780 skb_set_tail_pointer(skb, len);
2781 }
2782
2783 if (!skb->sk || skb->destructor == sock_edemux)
2784 skb_condense(skb);
2785 return 0;
2786}
2787EXPORT_SYMBOL(___pskb_trim);
2788
2789/* Note : use pskb_trim_rcsum() instead of calling this directly
2790 */
2791int pskb_trim_rcsum_slow(struct sk_buff *skb, unsigned int len)
2792{
2793 if (skb->ip_summed == CHECKSUM_COMPLETE) {
2794 int delta = skb->len - len;
2795
2796 skb->csum = csum_block_sub(skb->csum,
2797 skb_checksum(skb, len, delta, 0),
2798 len);
2799 } else if (skb->ip_summed == CHECKSUM_PARTIAL) {
2800 int hdlen = (len > skb_headlen(skb)) ? skb_headlen(skb) : len;
2801 int offset = skb_checksum_start_offset(skb) + skb->csum_offset;
2802
2803 if (offset + sizeof(__sum16) > hdlen)
2804 return -EINVAL;
2805 }
2806 return __pskb_trim(skb, len);
2807}
2808EXPORT_SYMBOL(pskb_trim_rcsum_slow);
2809
2810/**
2811 * __pskb_pull_tail - advance tail of skb header
2812 * @skb: buffer to reallocate
2813 * @delta: number of bytes to advance tail
2814 *
2815 * The function makes a sense only on a fragmented &sk_buff,
2816 * it expands header moving its tail forward and copying necessary
2817 * data from fragmented part.
2818 *
2819 * &sk_buff MUST have reference count of 1.
2820 *
2821 * Returns %NULL (and &sk_buff does not change) if pull failed
2822 * or value of new tail of skb in the case of success.
2823 *
2824 * All the pointers pointing into skb header may change and must be
2825 * reloaded after call to this function.
2826 */
2827
2828/* Moves tail of skb head forward, copying data from fragmented part,
2829 * when it is necessary.
2830 * 1. It may fail due to malloc failure.
2831 * 2. It may change skb pointers.
2832 *
2833 * It is pretty complicated. Luckily, it is called only in exceptional cases.
2834 */
2835void *__pskb_pull_tail(struct sk_buff *skb, int delta)
2836{
2837 /* If skb has not enough free space at tail, get new one
2838 * plus 128 bytes for future expansions. If we have enough
2839 * room at tail, reallocate without expansion only if skb is cloned.
2840 */
2841 int i, k, eat = (skb->tail + delta) - skb->end;
2842
2843 if (!skb_frags_readable(skb))
2844 return NULL;
2845
2846 if (eat > 0 || skb_cloned(skb)) {
2847 if (pskb_expand_head(skb, 0, eat > 0 ? eat + 128 : 0,
2848 GFP_ATOMIC))
2849 return NULL;
2850 }
2851
2852 BUG_ON(skb_copy_bits(skb, skb_headlen(skb),
2853 skb_tail_pointer(skb), delta));
2854
2855 /* Optimization: no fragments, no reasons to preestimate
2856 * size of pulled pages. Superb.
2857 */
2858 if (!skb_has_frag_list(skb))
2859 goto pull_pages;
2860
2861 /* Estimate size of pulled pages. */
2862 eat = delta;
2863 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
2864 int size = skb_frag_size(&skb_shinfo(skb)->frags[i]);
2865
2866 if (size >= eat)
2867 goto pull_pages;
2868 eat -= size;
2869 }
2870
2871 /* If we need update frag list, we are in troubles.
2872 * Certainly, it is possible to add an offset to skb data,
2873 * but taking into account that pulling is expected to
2874 * be very rare operation, it is worth to fight against
2875 * further bloating skb head and crucify ourselves here instead.
2876 * Pure masohism, indeed. 8)8)
2877 */
2878 if (eat) {
2879 struct sk_buff *list = skb_shinfo(skb)->frag_list;
2880 struct sk_buff *clone = NULL;
2881 struct sk_buff *insp = NULL;
2882
2883 do {
2884 if (list->len <= eat) {
2885 /* Eaten as whole. */
2886 eat -= list->len;
2887 list = list->next;
2888 insp = list;
2889 } else {
2890 /* Eaten partially. */
2891 if (skb_is_gso(skb) && !list->head_frag &&
2892 skb_headlen(list))
2893 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
2894
2895 if (skb_shared(list)) {
2896 /* Sucks! We need to fork list. :-( */
2897 clone = skb_clone(list, GFP_ATOMIC);
2898 if (!clone)
2899 return NULL;
2900 insp = list->next;
2901 list = clone;
2902 } else {
2903 /* This may be pulled without
2904 * problems. */
2905 insp = list;
2906 }
2907 if (!pskb_pull(list, eat)) {
2908 kfree_skb(clone);
2909 return NULL;
2910 }
2911 break;
2912 }
2913 } while (eat);
2914
2915 /* Free pulled out fragments. */
2916 while ((list = skb_shinfo(skb)->frag_list) != insp) {
2917 skb_shinfo(skb)->frag_list = list->next;
2918 consume_skb(list);
2919 }
2920 /* And insert new clone at head. */
2921 if (clone) {
2922 clone->next = list;
2923 skb_shinfo(skb)->frag_list = clone;
2924 }
2925 }
2926 /* Success! Now we may commit changes to skb data. */
2927
2928pull_pages:
2929 eat = delta;
2930 k = 0;
2931 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
2932 int size = skb_frag_size(&skb_shinfo(skb)->frags[i]);
2933
2934 if (size <= eat) {
2935 skb_frag_unref(skb, i);
2936 eat -= size;
2937 } else {
2938 skb_frag_t *frag = &skb_shinfo(skb)->frags[k];
2939
2940 *frag = skb_shinfo(skb)->frags[i];
2941 if (eat) {
2942 skb_frag_off_add(frag, eat);
2943 skb_frag_size_sub(frag, eat);
2944 if (!i)
2945 goto end;
2946 eat = 0;
2947 }
2948 k++;
2949 }
2950 }
2951 skb_shinfo(skb)->nr_frags = k;
2952
2953end:
2954 skb->tail += delta;
2955 skb->data_len -= delta;
2956
2957 if (!skb->data_len)
2958 skb_zcopy_clear(skb, false);
2959
2960 return skb_tail_pointer(skb);
2961}
2962EXPORT_SYMBOL(__pskb_pull_tail);
2963
2964/**
2965 * skb_copy_bits - copy bits from skb to kernel buffer
2966 * @skb: source skb
2967 * @offset: offset in source
2968 * @to: destination buffer
2969 * @len: number of bytes to copy
2970 *
2971 * Copy the specified number of bytes from the source skb to the
2972 * destination buffer.
2973 *
2974 * CAUTION ! :
2975 * If its prototype is ever changed,
2976 * check arch/{*}/net/{*}.S files,
2977 * since it is called from BPF assembly code.
2978 */
2979int skb_copy_bits(const struct sk_buff *skb, int offset, void *to, int len)
2980{
2981 int start = skb_headlen(skb);
2982 struct sk_buff *frag_iter;
2983 int i, copy;
2984
2985 if (offset > (int)skb->len - len)
2986 goto fault;
2987
2988 /* Copy header. */
2989 if ((copy = start - offset) > 0) {
2990 if (copy > len)
2991 copy = len;
2992 skb_copy_from_linear_data_offset(skb, offset, to, copy);
2993 if ((len -= copy) == 0)
2994 return 0;
2995 offset += copy;
2996 to += copy;
2997 }
2998
2999 if (!skb_frags_readable(skb))
3000 goto fault;
3001
3002 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
3003 int end;
3004 skb_frag_t *f = &skb_shinfo(skb)->frags[i];
3005
3006 WARN_ON(start > offset + len);
3007
3008 end = start + skb_frag_size(f);
3009 if ((copy = end - offset) > 0) {
3010 u32 p_off, p_len, copied;
3011 struct page *p;
3012 u8 *vaddr;
3013
3014 if (copy > len)
3015 copy = len;
3016
3017 skb_frag_foreach_page(f,
3018 skb_frag_off(f) + offset - start,
3019 copy, p, p_off, p_len, copied) {
3020 vaddr = kmap_atomic(p);
3021 memcpy(to + copied, vaddr + p_off, p_len);
3022 kunmap_atomic(vaddr);
3023 }
3024
3025 if ((len -= copy) == 0)
3026 return 0;
3027 offset += copy;
3028 to += copy;
3029 }
3030 start = end;
3031 }
3032
3033 skb_walk_frags(skb, frag_iter) {
3034 int end;
3035
3036 WARN_ON(start > offset + len);
3037
3038 end = start + frag_iter->len;
3039 if ((copy = end - offset) > 0) {
3040 if (copy > len)
3041 copy = len;
3042 if (skb_copy_bits(frag_iter, offset - start, to, copy))
3043 goto fault;
3044 if ((len -= copy) == 0)
3045 return 0;
3046 offset += copy;
3047 to += copy;
3048 }
3049 start = end;
3050 }
3051
3052 if (!len)
3053 return 0;
3054
3055fault:
3056 return -EFAULT;
3057}
3058EXPORT_SYMBOL(skb_copy_bits);
3059
3060/*
3061 * Callback from splice_to_pipe(), if we need to release some pages
3062 * at the end of the spd in case we error'ed out in filling the pipe.
3063 */
3064static void sock_spd_release(struct splice_pipe_desc *spd, unsigned int i)
3065{
3066 put_page(spd->pages[i]);
3067}
3068
3069static struct page *linear_to_page(struct page *page, unsigned int *len,
3070 unsigned int *offset,
3071 struct sock *sk)
3072{
3073 struct page_frag *pfrag = sk_page_frag(sk);
3074
3075 if (!sk_page_frag_refill(sk, pfrag))
3076 return NULL;
3077
3078 *len = min_t(unsigned int, *len, pfrag->size - pfrag->offset);
3079
3080 memcpy(page_address(pfrag->page) + pfrag->offset,
3081 page_address(page) + *offset, *len);
3082 *offset = pfrag->offset;
3083 pfrag->offset += *len;
3084
3085 return pfrag->page;
3086}
3087
3088static bool spd_can_coalesce(const struct splice_pipe_desc *spd,
3089 struct page *page,
3090 unsigned int offset)
3091{
3092 return spd->nr_pages &&
3093 spd->pages[spd->nr_pages - 1] == page &&
3094 (spd->partial[spd->nr_pages - 1].offset +
3095 spd->partial[spd->nr_pages - 1].len == offset);
3096}
3097
3098/*
3099 * Fill page/offset/length into spd, if it can hold more pages.
3100 */
3101static bool spd_fill_page(struct splice_pipe_desc *spd,
3102 struct pipe_inode_info *pipe, struct page *page,
3103 unsigned int *len, unsigned int offset,
3104 bool linear,
3105 struct sock *sk)
3106{
3107 if (unlikely(spd->nr_pages == MAX_SKB_FRAGS))
3108 return true;
3109
3110 if (linear) {
3111 page = linear_to_page(page, len, &offset, sk);
3112 if (!page)
3113 return true;
3114 }
3115 if (spd_can_coalesce(spd, page, offset)) {
3116 spd->partial[spd->nr_pages - 1].len += *len;
3117 return false;
3118 }
3119 get_page(page);
3120 spd->pages[spd->nr_pages] = page;
3121 spd->partial[spd->nr_pages].len = *len;
3122 spd->partial[spd->nr_pages].offset = offset;
3123 spd->nr_pages++;
3124
3125 return false;
3126}
3127
3128static bool __splice_segment(struct page *page, unsigned int poff,
3129 unsigned int plen, unsigned int *off,
3130 unsigned int *len,
3131 struct splice_pipe_desc *spd, bool linear,
3132 struct sock *sk,
3133 struct pipe_inode_info *pipe)
3134{
3135 if (!*len)
3136 return true;
3137
3138 /* skip this segment if already processed */
3139 if (*off >= plen) {
3140 *off -= plen;
3141 return false;
3142 }
3143
3144 /* ignore any bits we already processed */
3145 poff += *off;
3146 plen -= *off;
3147 *off = 0;
3148
3149 do {
3150 unsigned int flen = min(*len, plen);
3151
3152 if (spd_fill_page(spd, pipe, page, &flen, poff,
3153 linear, sk))
3154 return true;
3155 poff += flen;
3156 plen -= flen;
3157 *len -= flen;
3158 } while (*len && plen);
3159
3160 return false;
3161}
3162
3163/*
3164 * Map linear and fragment data from the skb to spd. It reports true if the
3165 * pipe is full or if we already spliced the requested length.
3166 */
3167static bool __skb_splice_bits(struct sk_buff *skb, struct pipe_inode_info *pipe,
3168 unsigned int *offset, unsigned int *len,
3169 struct splice_pipe_desc *spd, struct sock *sk)
3170{
3171 int seg;
3172 struct sk_buff *iter;
3173
3174 /* map the linear part :
3175 * If skb->head_frag is set, this 'linear' part is backed by a
3176 * fragment, and if the head is not shared with any clones then
3177 * we can avoid a copy since we own the head portion of this page.
3178 */
3179 if (__splice_segment(virt_to_page(skb->data),
3180 (unsigned long) skb->data & (PAGE_SIZE - 1),
3181 skb_headlen(skb),
3182 offset, len, spd,
3183 skb_head_is_locked(skb),
3184 sk, pipe))
3185 return true;
3186
3187 /*
3188 * then map the fragments
3189 */
3190 if (!skb_frags_readable(skb))
3191 return false;
3192
3193 for (seg = 0; seg < skb_shinfo(skb)->nr_frags; seg++) {
3194 const skb_frag_t *f = &skb_shinfo(skb)->frags[seg];
3195
3196 if (WARN_ON_ONCE(!skb_frag_page(f)))
3197 return false;
3198
3199 if (__splice_segment(skb_frag_page(f),
3200 skb_frag_off(f), skb_frag_size(f),
3201 offset, len, spd, false, sk, pipe))
3202 return true;
3203 }
3204
3205 skb_walk_frags(skb, iter) {
3206 if (*offset >= iter->len) {
3207 *offset -= iter->len;
3208 continue;
3209 }
3210 /* __skb_splice_bits() only fails if the output has no room
3211 * left, so no point in going over the frag_list for the error
3212 * case.
3213 */
3214 if (__skb_splice_bits(iter, pipe, offset, len, spd, sk))
3215 return true;
3216 }
3217
3218 return false;
3219}
3220
3221/*
3222 * Map data from the skb to a pipe. Should handle both the linear part,
3223 * the fragments, and the frag list.
3224 */
3225int skb_splice_bits(struct sk_buff *skb, struct sock *sk, unsigned int offset,
3226 struct pipe_inode_info *pipe, unsigned int tlen,
3227 unsigned int flags)
3228{
3229 struct partial_page partial[MAX_SKB_FRAGS];
3230 struct page *pages[MAX_SKB_FRAGS];
3231 struct splice_pipe_desc spd = {
3232 .pages = pages,
3233 .partial = partial,
3234 .nr_pages_max = MAX_SKB_FRAGS,
3235 .ops = &nosteal_pipe_buf_ops,
3236 .spd_release = sock_spd_release,
3237 };
3238 int ret = 0;
3239
3240 __skb_splice_bits(skb, pipe, &offset, &tlen, &spd, sk);
3241
3242 if (spd.nr_pages)
3243 ret = splice_to_pipe(pipe, &spd);
3244
3245 return ret;
3246}
3247EXPORT_SYMBOL_GPL(skb_splice_bits);
3248
3249static int sendmsg_locked(struct sock *sk, struct msghdr *msg)
3250{
3251 struct socket *sock = sk->sk_socket;
3252 size_t size = msg_data_left(msg);
3253
3254 if (!sock)
3255 return -EINVAL;
3256
3257 if (!sock->ops->sendmsg_locked)
3258 return sock_no_sendmsg_locked(sk, msg, size);
3259
3260 return sock->ops->sendmsg_locked(sk, msg, size);
3261}
3262
3263static int sendmsg_unlocked(struct sock *sk, struct msghdr *msg)
3264{
3265 struct socket *sock = sk->sk_socket;
3266
3267 if (!sock)
3268 return -EINVAL;
3269 return sock_sendmsg(sock, msg);
3270}
3271
3272typedef int (*sendmsg_func)(struct sock *sk, struct msghdr *msg);
3273static int __skb_send_sock(struct sock *sk, struct sk_buff *skb, int offset,
3274 int len, sendmsg_func sendmsg)
3275{
3276 unsigned int orig_len = len;
3277 struct sk_buff *head = skb;
3278 unsigned short fragidx;
3279 int slen, ret;
3280
3281do_frag_list:
3282
3283 /* Deal with head data */
3284 while (offset < skb_headlen(skb) && len) {
3285 struct kvec kv;
3286 struct msghdr msg;
3287
3288 slen = min_t(int, len, skb_headlen(skb) - offset);
3289 kv.iov_base = skb->data + offset;
3290 kv.iov_len = slen;
3291 memset(&msg, 0, sizeof(msg));
3292 msg.msg_flags = MSG_DONTWAIT;
3293
3294 iov_iter_kvec(&msg.msg_iter, ITER_SOURCE, &kv, 1, slen);
3295 ret = INDIRECT_CALL_2(sendmsg, sendmsg_locked,
3296 sendmsg_unlocked, sk, &msg);
3297 if (ret <= 0)
3298 goto error;
3299
3300 offset += ret;
3301 len -= ret;
3302 }
3303
3304 /* All the data was skb head? */
3305 if (!len)
3306 goto out;
3307
3308 /* Make offset relative to start of frags */
3309 offset -= skb_headlen(skb);
3310
3311 /* Find where we are in frag list */
3312 for (fragidx = 0; fragidx < skb_shinfo(skb)->nr_frags; fragidx++) {
3313 skb_frag_t *frag = &skb_shinfo(skb)->frags[fragidx];
3314
3315 if (offset < skb_frag_size(frag))
3316 break;
3317
3318 offset -= skb_frag_size(frag);
3319 }
3320
3321 for (; len && fragidx < skb_shinfo(skb)->nr_frags; fragidx++) {
3322 skb_frag_t *frag = &skb_shinfo(skb)->frags[fragidx];
3323
3324 slen = min_t(size_t, len, skb_frag_size(frag) - offset);
3325
3326 while (slen) {
3327 struct bio_vec bvec;
3328 struct msghdr msg = {
3329 .msg_flags = MSG_SPLICE_PAGES | MSG_DONTWAIT,
3330 };
3331
3332 bvec_set_page(&bvec, skb_frag_page(frag), slen,
3333 skb_frag_off(frag) + offset);
3334 iov_iter_bvec(&msg.msg_iter, ITER_SOURCE, &bvec, 1,
3335 slen);
3336
3337 ret = INDIRECT_CALL_2(sendmsg, sendmsg_locked,
3338 sendmsg_unlocked, sk, &msg);
3339 if (ret <= 0)
3340 goto error;
3341
3342 len -= ret;
3343 offset += ret;
3344 slen -= ret;
3345 }
3346
3347 offset = 0;
3348 }
3349
3350 if (len) {
3351 /* Process any frag lists */
3352
3353 if (skb == head) {
3354 if (skb_has_frag_list(skb)) {
3355 skb = skb_shinfo(skb)->frag_list;
3356 goto do_frag_list;
3357 }
3358 } else if (skb->next) {
3359 skb = skb->next;
3360 goto do_frag_list;
3361 }
3362 }
3363
3364out:
3365 return orig_len - len;
3366
3367error:
3368 return orig_len == len ? ret : orig_len - len;
3369}
3370
3371/* Send skb data on a socket. Socket must be locked. */
3372int skb_send_sock_locked(struct sock *sk, struct sk_buff *skb, int offset,
3373 int len)
3374{
3375 return __skb_send_sock(sk, skb, offset, len, sendmsg_locked);
3376}
3377EXPORT_SYMBOL_GPL(skb_send_sock_locked);
3378
3379/* Send skb data on a socket. Socket must be unlocked. */
3380int skb_send_sock(struct sock *sk, struct sk_buff *skb, int offset, int len)
3381{
3382 return __skb_send_sock(sk, skb, offset, len, sendmsg_unlocked);
3383}
3384
3385/**
3386 * skb_store_bits - store bits from kernel buffer to skb
3387 * @skb: destination buffer
3388 * @offset: offset in destination
3389 * @from: source buffer
3390 * @len: number of bytes to copy
3391 *
3392 * Copy the specified number of bytes from the source buffer to the
3393 * destination skb. This function handles all the messy bits of
3394 * traversing fragment lists and such.
3395 */
3396
3397int skb_store_bits(struct sk_buff *skb, int offset, const void *from, int len)
3398{
3399 int start = skb_headlen(skb);
3400 struct sk_buff *frag_iter;
3401 int i, copy;
3402
3403 if (offset > (int)skb->len - len)
3404 goto fault;
3405
3406 if ((copy = start - offset) > 0) {
3407 if (copy > len)
3408 copy = len;
3409 skb_copy_to_linear_data_offset(skb, offset, from, copy);
3410 if ((len -= copy) == 0)
3411 return 0;
3412 offset += copy;
3413 from += copy;
3414 }
3415
3416 if (!skb_frags_readable(skb))
3417 goto fault;
3418
3419 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
3420 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
3421 int end;
3422
3423 WARN_ON(start > offset + len);
3424
3425 end = start + skb_frag_size(frag);
3426 if ((copy = end - offset) > 0) {
3427 u32 p_off, p_len, copied;
3428 struct page *p;
3429 u8 *vaddr;
3430
3431 if (copy > len)
3432 copy = len;
3433
3434 skb_frag_foreach_page(frag,
3435 skb_frag_off(frag) + offset - start,
3436 copy, p, p_off, p_len, copied) {
3437 vaddr = kmap_atomic(p);
3438 memcpy(vaddr + p_off, from + copied, p_len);
3439 kunmap_atomic(vaddr);
3440 }
3441
3442 if ((len -= copy) == 0)
3443 return 0;
3444 offset += copy;
3445 from += copy;
3446 }
3447 start = end;
3448 }
3449
3450 skb_walk_frags(skb, frag_iter) {
3451 int end;
3452
3453 WARN_ON(start > offset + len);
3454
3455 end = start + frag_iter->len;
3456 if ((copy = end - offset) > 0) {
3457 if (copy > len)
3458 copy = len;
3459 if (skb_store_bits(frag_iter, offset - start,
3460 from, copy))
3461 goto fault;
3462 if ((len -= copy) == 0)
3463 return 0;
3464 offset += copy;
3465 from += copy;
3466 }
3467 start = end;
3468 }
3469 if (!len)
3470 return 0;
3471
3472fault:
3473 return -EFAULT;
3474}
3475EXPORT_SYMBOL(skb_store_bits);
3476
3477/* Checksum skb data. */
3478__wsum __skb_checksum(const struct sk_buff *skb, int offset, int len,
3479 __wsum csum, const struct skb_checksum_ops *ops)
3480{
3481 int start = skb_headlen(skb);
3482 int i, copy = start - offset;
3483 struct sk_buff *frag_iter;
3484 int pos = 0;
3485
3486 /* Checksum header. */
3487 if (copy > 0) {
3488 if (copy > len)
3489 copy = len;
3490 csum = INDIRECT_CALL_1(ops->update, csum_partial_ext,
3491 skb->data + offset, copy, csum);
3492 if ((len -= copy) == 0)
3493 return csum;
3494 offset += copy;
3495 pos = copy;
3496 }
3497
3498 if (WARN_ON_ONCE(!skb_frags_readable(skb)))
3499 return 0;
3500
3501 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
3502 int end;
3503 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
3504
3505 WARN_ON(start > offset + len);
3506
3507 end = start + skb_frag_size(frag);
3508 if ((copy = end - offset) > 0) {
3509 u32 p_off, p_len, copied;
3510 struct page *p;
3511 __wsum csum2;
3512 u8 *vaddr;
3513
3514 if (copy > len)
3515 copy = len;
3516
3517 skb_frag_foreach_page(frag,
3518 skb_frag_off(frag) + offset - start,
3519 copy, p, p_off, p_len, copied) {
3520 vaddr = kmap_atomic(p);
3521 csum2 = INDIRECT_CALL_1(ops->update,
3522 csum_partial_ext,
3523 vaddr + p_off, p_len, 0);
3524 kunmap_atomic(vaddr);
3525 csum = INDIRECT_CALL_1(ops->combine,
3526 csum_block_add_ext, csum,
3527 csum2, pos, p_len);
3528 pos += p_len;
3529 }
3530
3531 if (!(len -= copy))
3532 return csum;
3533 offset += copy;
3534 }
3535 start = end;
3536 }
3537
3538 skb_walk_frags(skb, frag_iter) {
3539 int end;
3540
3541 WARN_ON(start > offset + len);
3542
3543 end = start + frag_iter->len;
3544 if ((copy = end - offset) > 0) {
3545 __wsum csum2;
3546 if (copy > len)
3547 copy = len;
3548 csum2 = __skb_checksum(frag_iter, offset - start,
3549 copy, 0, ops);
3550 csum = INDIRECT_CALL_1(ops->combine, csum_block_add_ext,
3551 csum, csum2, pos, copy);
3552 if ((len -= copy) == 0)
3553 return csum;
3554 offset += copy;
3555 pos += copy;
3556 }
3557 start = end;
3558 }
3559 BUG_ON(len);
3560
3561 return csum;
3562}
3563EXPORT_SYMBOL(__skb_checksum);
3564
3565__wsum skb_checksum(const struct sk_buff *skb, int offset,
3566 int len, __wsum csum)
3567{
3568 const struct skb_checksum_ops ops = {
3569 .update = csum_partial_ext,
3570 .combine = csum_block_add_ext,
3571 };
3572
3573 return __skb_checksum(skb, offset, len, csum, &ops);
3574}
3575EXPORT_SYMBOL(skb_checksum);
3576
3577/* Both of above in one bottle. */
3578
3579__wsum skb_copy_and_csum_bits(const struct sk_buff *skb, int offset,
3580 u8 *to, int len)
3581{
3582 int start = skb_headlen(skb);
3583 int i, copy = start - offset;
3584 struct sk_buff *frag_iter;
3585 int pos = 0;
3586 __wsum csum = 0;
3587
3588 /* Copy header. */
3589 if (copy > 0) {
3590 if (copy > len)
3591 copy = len;
3592 csum = csum_partial_copy_nocheck(skb->data + offset, to,
3593 copy);
3594 if ((len -= copy) == 0)
3595 return csum;
3596 offset += copy;
3597 to += copy;
3598 pos = copy;
3599 }
3600
3601 if (!skb_frags_readable(skb))
3602 return 0;
3603
3604 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
3605 int end;
3606
3607 WARN_ON(start > offset + len);
3608
3609 end = start + skb_frag_size(&skb_shinfo(skb)->frags[i]);
3610 if ((copy = end - offset) > 0) {
3611 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
3612 u32 p_off, p_len, copied;
3613 struct page *p;
3614 __wsum csum2;
3615 u8 *vaddr;
3616
3617 if (copy > len)
3618 copy = len;
3619
3620 skb_frag_foreach_page(frag,
3621 skb_frag_off(frag) + offset - start,
3622 copy, p, p_off, p_len, copied) {
3623 vaddr = kmap_atomic(p);
3624 csum2 = csum_partial_copy_nocheck(vaddr + p_off,
3625 to + copied,
3626 p_len);
3627 kunmap_atomic(vaddr);
3628 csum = csum_block_add(csum, csum2, pos);
3629 pos += p_len;
3630 }
3631
3632 if (!(len -= copy))
3633 return csum;
3634 offset += copy;
3635 to += copy;
3636 }
3637 start = end;
3638 }
3639
3640 skb_walk_frags(skb, frag_iter) {
3641 __wsum csum2;
3642 int end;
3643
3644 WARN_ON(start > offset + len);
3645
3646 end = start + frag_iter->len;
3647 if ((copy = end - offset) > 0) {
3648 if (copy > len)
3649 copy = len;
3650 csum2 = skb_copy_and_csum_bits(frag_iter,
3651 offset - start,
3652 to, copy);
3653 csum = csum_block_add(csum, csum2, pos);
3654 if ((len -= copy) == 0)
3655 return csum;
3656 offset += copy;
3657 to += copy;
3658 pos += copy;
3659 }
3660 start = end;
3661 }
3662 BUG_ON(len);
3663 return csum;
3664}
3665EXPORT_SYMBOL(skb_copy_and_csum_bits);
3666
3667__sum16 __skb_checksum_complete_head(struct sk_buff *skb, int len)
3668{
3669 __sum16 sum;
3670
3671 sum = csum_fold(skb_checksum(skb, 0, len, skb->csum));
3672 /* See comments in __skb_checksum_complete(). */
3673 if (likely(!sum)) {
3674 if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE) &&
3675 !skb->csum_complete_sw)
3676 netdev_rx_csum_fault(skb->dev, skb);
3677 }
3678 if (!skb_shared(skb))
3679 skb->csum_valid = !sum;
3680 return sum;
3681}
3682EXPORT_SYMBOL(__skb_checksum_complete_head);
3683
3684/* This function assumes skb->csum already holds pseudo header's checksum,
3685 * which has been changed from the hardware checksum, for example, by
3686 * __skb_checksum_validate_complete(). And, the original skb->csum must
3687 * have been validated unsuccessfully for CHECKSUM_COMPLETE case.
3688 *
3689 * It returns non-zero if the recomputed checksum is still invalid, otherwise
3690 * zero. The new checksum is stored back into skb->csum unless the skb is
3691 * shared.
3692 */
3693__sum16 __skb_checksum_complete(struct sk_buff *skb)
3694{
3695 __wsum csum;
3696 __sum16 sum;
3697
3698 csum = skb_checksum(skb, 0, skb->len, 0);
3699
3700 sum = csum_fold(csum_add(skb->csum, csum));
3701 /* This check is inverted, because we already knew the hardware
3702 * checksum is invalid before calling this function. So, if the
3703 * re-computed checksum is valid instead, then we have a mismatch
3704 * between the original skb->csum and skb_checksum(). This means either
3705 * the original hardware checksum is incorrect or we screw up skb->csum
3706 * when moving skb->data around.
3707 */
3708 if (likely(!sum)) {
3709 if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE) &&
3710 !skb->csum_complete_sw)
3711 netdev_rx_csum_fault(skb->dev, skb);
3712 }
3713
3714 if (!skb_shared(skb)) {
3715 /* Save full packet checksum */
3716 skb->csum = csum;
3717 skb->ip_summed = CHECKSUM_COMPLETE;
3718 skb->csum_complete_sw = 1;
3719 skb->csum_valid = !sum;
3720 }
3721
3722 return sum;
3723}
3724EXPORT_SYMBOL(__skb_checksum_complete);
3725
3726static __wsum warn_crc32c_csum_update(const void *buff, int len, __wsum sum)
3727{
3728 net_warn_ratelimited(
3729 "%s: attempt to compute crc32c without libcrc32c.ko\n",
3730 __func__);
3731 return 0;
3732}
3733
3734static __wsum warn_crc32c_csum_combine(__wsum csum, __wsum csum2,
3735 int offset, int len)
3736{
3737 net_warn_ratelimited(
3738 "%s: attempt to compute crc32c without libcrc32c.ko\n",
3739 __func__);
3740 return 0;
3741}
3742
3743static const struct skb_checksum_ops default_crc32c_ops = {
3744 .update = warn_crc32c_csum_update,
3745 .combine = warn_crc32c_csum_combine,
3746};
3747
3748const struct skb_checksum_ops *crc32c_csum_stub __read_mostly =
3749 &default_crc32c_ops;
3750EXPORT_SYMBOL(crc32c_csum_stub);
3751
3752 /**
3753 * skb_zerocopy_headlen - Calculate headroom needed for skb_zerocopy()
3754 * @from: source buffer
3755 *
3756 * Calculates the amount of linear headroom needed in the 'to' skb passed
3757 * into skb_zerocopy().
3758 */
3759unsigned int
3760skb_zerocopy_headlen(const struct sk_buff *from)
3761{
3762 unsigned int hlen = 0;
3763
3764 if (!from->head_frag ||
3765 skb_headlen(from) < L1_CACHE_BYTES ||
3766 skb_shinfo(from)->nr_frags >= MAX_SKB_FRAGS) {
3767 hlen = skb_headlen(from);
3768 if (!hlen)
3769 hlen = from->len;
3770 }
3771
3772 if (skb_has_frag_list(from))
3773 hlen = from->len;
3774
3775 return hlen;
3776}
3777EXPORT_SYMBOL_GPL(skb_zerocopy_headlen);
3778
3779/**
3780 * skb_zerocopy - Zero copy skb to skb
3781 * @to: destination buffer
3782 * @from: source buffer
3783 * @len: number of bytes to copy from source buffer
3784 * @hlen: size of linear headroom in destination buffer
3785 *
3786 * Copies up to `len` bytes from `from` to `to` by creating references
3787 * to the frags in the source buffer.
3788 *
3789 * The `hlen` as calculated by skb_zerocopy_headlen() specifies the
3790 * headroom in the `to` buffer.
3791 *
3792 * Return value:
3793 * 0: everything is OK
3794 * -ENOMEM: couldn't orphan frags of @from due to lack of memory
3795 * -EFAULT: skb_copy_bits() found some problem with skb geometry
3796 */
3797int
3798skb_zerocopy(struct sk_buff *to, struct sk_buff *from, int len, int hlen)
3799{
3800 int i, j = 0;
3801 int plen = 0; /* length of skb->head fragment */
3802 int ret;
3803 struct page *page;
3804 unsigned int offset;
3805
3806 BUG_ON(!from->head_frag && !hlen);
3807
3808 /* dont bother with small payloads */
3809 if (len <= skb_tailroom(to))
3810 return skb_copy_bits(from, 0, skb_put(to, len), len);
3811
3812 if (hlen) {
3813 ret = skb_copy_bits(from, 0, skb_put(to, hlen), hlen);
3814 if (unlikely(ret))
3815 return ret;
3816 len -= hlen;
3817 } else {
3818 plen = min_t(int, skb_headlen(from), len);
3819 if (plen) {
3820 page = virt_to_head_page(from->head);
3821 offset = from->data - (unsigned char *)page_address(page);
3822 __skb_fill_netmem_desc(to, 0, page_to_netmem(page),
3823 offset, plen);
3824 get_page(page);
3825 j = 1;
3826 len -= plen;
3827 }
3828 }
3829
3830 skb_len_add(to, len + plen);
3831
3832 if (unlikely(skb_orphan_frags(from, GFP_ATOMIC))) {
3833 skb_tx_error(from);
3834 return -ENOMEM;
3835 }
3836 skb_zerocopy_clone(to, from, GFP_ATOMIC);
3837
3838 for (i = 0; i < skb_shinfo(from)->nr_frags; i++) {
3839 int size;
3840
3841 if (!len)
3842 break;
3843 skb_shinfo(to)->frags[j] = skb_shinfo(from)->frags[i];
3844 size = min_t(int, skb_frag_size(&skb_shinfo(to)->frags[j]),
3845 len);
3846 skb_frag_size_set(&skb_shinfo(to)->frags[j], size);
3847 len -= size;
3848 skb_frag_ref(to, j);
3849 j++;
3850 }
3851 skb_shinfo(to)->nr_frags = j;
3852
3853 return 0;
3854}
3855EXPORT_SYMBOL_GPL(skb_zerocopy);
3856
3857void skb_copy_and_csum_dev(const struct sk_buff *skb, u8 *to)
3858{
3859 __wsum csum;
3860 long csstart;
3861
3862 if (skb->ip_summed == CHECKSUM_PARTIAL)
3863 csstart = skb_checksum_start_offset(skb);
3864 else
3865 csstart = skb_headlen(skb);
3866
3867 BUG_ON(csstart > skb_headlen(skb));
3868
3869 skb_copy_from_linear_data(skb, to, csstart);
3870
3871 csum = 0;
3872 if (csstart != skb->len)
3873 csum = skb_copy_and_csum_bits(skb, csstart, to + csstart,
3874 skb->len - csstart);
3875
3876 if (skb->ip_summed == CHECKSUM_PARTIAL) {
3877 long csstuff = csstart + skb->csum_offset;
3878
3879 *((__sum16 *)(to + csstuff)) = csum_fold(csum);
3880 }
3881}
3882EXPORT_SYMBOL(skb_copy_and_csum_dev);
3883
3884/**
3885 * skb_dequeue - remove from the head of the queue
3886 * @list: list to dequeue from
3887 *
3888 * Remove the head of the list. The list lock is taken so the function
3889 * may be used safely with other locking list functions. The head item is
3890 * returned or %NULL if the list is empty.
3891 */
3892
3893struct sk_buff *skb_dequeue(struct sk_buff_head *list)
3894{
3895 unsigned long flags;
3896 struct sk_buff *result;
3897
3898 spin_lock_irqsave(&list->lock, flags);
3899 result = __skb_dequeue(list);
3900 spin_unlock_irqrestore(&list->lock, flags);
3901 return result;
3902}
3903EXPORT_SYMBOL(skb_dequeue);
3904
3905/**
3906 * skb_dequeue_tail - remove from the tail of the queue
3907 * @list: list to dequeue from
3908 *
3909 * Remove the tail of the list. The list lock is taken so the function
3910 * may be used safely with other locking list functions. The tail item is
3911 * returned or %NULL if the list is empty.
3912 */
3913struct sk_buff *skb_dequeue_tail(struct sk_buff_head *list)
3914{
3915 unsigned long flags;
3916 struct sk_buff *result;
3917
3918 spin_lock_irqsave(&list->lock, flags);
3919 result = __skb_dequeue_tail(list);
3920 spin_unlock_irqrestore(&list->lock, flags);
3921 return result;
3922}
3923EXPORT_SYMBOL(skb_dequeue_tail);
3924
3925/**
3926 * skb_queue_purge_reason - empty a list
3927 * @list: list to empty
3928 * @reason: drop reason
3929 *
3930 * Delete all buffers on an &sk_buff list. Each buffer is removed from
3931 * the list and one reference dropped. This function takes the list
3932 * lock and is atomic with respect to other list locking functions.
3933 */
3934void skb_queue_purge_reason(struct sk_buff_head *list,
3935 enum skb_drop_reason reason)
3936{
3937 struct sk_buff_head tmp;
3938 unsigned long flags;
3939
3940 if (skb_queue_empty_lockless(list))
3941 return;
3942
3943 __skb_queue_head_init(&tmp);
3944
3945 spin_lock_irqsave(&list->lock, flags);
3946 skb_queue_splice_init(list, &tmp);
3947 spin_unlock_irqrestore(&list->lock, flags);
3948
3949 __skb_queue_purge_reason(&tmp, reason);
3950}
3951EXPORT_SYMBOL(skb_queue_purge_reason);
3952
3953/**
3954 * skb_rbtree_purge - empty a skb rbtree
3955 * @root: root of the rbtree to empty
3956 * Return value: the sum of truesizes of all purged skbs.
3957 *
3958 * Delete all buffers on an &sk_buff rbtree. Each buffer is removed from
3959 * the list and one reference dropped. This function does not take
3960 * any lock. Synchronization should be handled by the caller (e.g., TCP
3961 * out-of-order queue is protected by the socket lock).
3962 */
3963unsigned int skb_rbtree_purge(struct rb_root *root)
3964{
3965 struct rb_node *p = rb_first(root);
3966 unsigned int sum = 0;
3967
3968 while (p) {
3969 struct sk_buff *skb = rb_entry(p, struct sk_buff, rbnode);
3970
3971 p = rb_next(p);
3972 rb_erase(&skb->rbnode, root);
3973 sum += skb->truesize;
3974 kfree_skb(skb);
3975 }
3976 return sum;
3977}
3978
3979void skb_errqueue_purge(struct sk_buff_head *list)
3980{
3981 struct sk_buff *skb, *next;
3982 struct sk_buff_head kill;
3983 unsigned long flags;
3984
3985 __skb_queue_head_init(&kill);
3986
3987 spin_lock_irqsave(&list->lock, flags);
3988 skb_queue_walk_safe(list, skb, next) {
3989 if (SKB_EXT_ERR(skb)->ee.ee_origin == SO_EE_ORIGIN_ZEROCOPY ||
3990 SKB_EXT_ERR(skb)->ee.ee_origin == SO_EE_ORIGIN_TIMESTAMPING)
3991 continue;
3992 __skb_unlink(skb, list);
3993 __skb_queue_tail(&kill, skb);
3994 }
3995 spin_unlock_irqrestore(&list->lock, flags);
3996 __skb_queue_purge(&kill);
3997}
3998EXPORT_SYMBOL(skb_errqueue_purge);
3999
4000/**
4001 * skb_queue_head - queue a buffer at the list head
4002 * @list: list to use
4003 * @newsk: buffer to queue
4004 *
4005 * Queue a buffer at the start of the list. This function takes the
4006 * list lock and can be used safely with other locking &sk_buff functions
4007 * safely.
4008 *
4009 * A buffer cannot be placed on two lists at the same time.
4010 */
4011void skb_queue_head(struct sk_buff_head *list, struct sk_buff *newsk)
4012{
4013 unsigned long flags;
4014
4015 spin_lock_irqsave(&list->lock, flags);
4016 __skb_queue_head(list, newsk);
4017 spin_unlock_irqrestore(&list->lock, flags);
4018}
4019EXPORT_SYMBOL(skb_queue_head);
4020
4021/**
4022 * skb_queue_tail - queue a buffer at the list tail
4023 * @list: list to use
4024 * @newsk: buffer to queue
4025 *
4026 * Queue a buffer at the tail of the list. This function takes the
4027 * list lock and can be used safely with other locking &sk_buff functions
4028 * safely.
4029 *
4030 * A buffer cannot be placed on two lists at the same time.
4031 */
4032void skb_queue_tail(struct sk_buff_head *list, struct sk_buff *newsk)
4033{
4034 unsigned long flags;
4035
4036 spin_lock_irqsave(&list->lock, flags);
4037 __skb_queue_tail(list, newsk);
4038 spin_unlock_irqrestore(&list->lock, flags);
4039}
4040EXPORT_SYMBOL(skb_queue_tail);
4041
4042/**
4043 * skb_unlink - remove a buffer from a list
4044 * @skb: buffer to remove
4045 * @list: list to use
4046 *
4047 * Remove a packet from a list. The list locks are taken and this
4048 * function is atomic with respect to other list locked calls
4049 *
4050 * You must know what list the SKB is on.
4051 */
4052void skb_unlink(struct sk_buff *skb, struct sk_buff_head *list)
4053{
4054 unsigned long flags;
4055
4056 spin_lock_irqsave(&list->lock, flags);
4057 __skb_unlink(skb, list);
4058 spin_unlock_irqrestore(&list->lock, flags);
4059}
4060EXPORT_SYMBOL(skb_unlink);
4061
4062/**
4063 * skb_append - append a buffer
4064 * @old: buffer to insert after
4065 * @newsk: buffer to insert
4066 * @list: list to use
4067 *
4068 * Place a packet after a given packet in a list. The list locks are taken
4069 * and this function is atomic with respect to other list locked calls.
4070 * A buffer cannot be placed on two lists at the same time.
4071 */
4072void skb_append(struct sk_buff *old, struct sk_buff *newsk, struct sk_buff_head *list)
4073{
4074 unsigned long flags;
4075
4076 spin_lock_irqsave(&list->lock, flags);
4077 __skb_queue_after(list, old, newsk);
4078 spin_unlock_irqrestore(&list->lock, flags);
4079}
4080EXPORT_SYMBOL(skb_append);
4081
4082static inline void skb_split_inside_header(struct sk_buff *skb,
4083 struct sk_buff* skb1,
4084 const u32 len, const int pos)
4085{
4086 int i;
4087
4088 skb_copy_from_linear_data_offset(skb, len, skb_put(skb1, pos - len),
4089 pos - len);
4090 /* And move data appendix as is. */
4091 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
4092 skb_shinfo(skb1)->frags[i] = skb_shinfo(skb)->frags[i];
4093
4094 skb_shinfo(skb1)->nr_frags = skb_shinfo(skb)->nr_frags;
4095 skb1->unreadable = skb->unreadable;
4096 skb_shinfo(skb)->nr_frags = 0;
4097 skb1->data_len = skb->data_len;
4098 skb1->len += skb1->data_len;
4099 skb->data_len = 0;
4100 skb->len = len;
4101 skb_set_tail_pointer(skb, len);
4102}
4103
4104static inline void skb_split_no_header(struct sk_buff *skb,
4105 struct sk_buff* skb1,
4106 const u32 len, int pos)
4107{
4108 int i, k = 0;
4109 const int nfrags = skb_shinfo(skb)->nr_frags;
4110
4111 skb_shinfo(skb)->nr_frags = 0;
4112 skb1->len = skb1->data_len = skb->len - len;
4113 skb->len = len;
4114 skb->data_len = len - pos;
4115
4116 for (i = 0; i < nfrags; i++) {
4117 int size = skb_frag_size(&skb_shinfo(skb)->frags[i]);
4118
4119 if (pos + size > len) {
4120 skb_shinfo(skb1)->frags[k] = skb_shinfo(skb)->frags[i];
4121
4122 if (pos < len) {
4123 /* Split frag.
4124 * We have two variants in this case:
4125 * 1. Move all the frag to the second
4126 * part, if it is possible. F.e.
4127 * this approach is mandatory for TUX,
4128 * where splitting is expensive.
4129 * 2. Split is accurately. We make this.
4130 */
4131 skb_frag_ref(skb, i);
4132 skb_frag_off_add(&skb_shinfo(skb1)->frags[0], len - pos);
4133 skb_frag_size_sub(&skb_shinfo(skb1)->frags[0], len - pos);
4134 skb_frag_size_set(&skb_shinfo(skb)->frags[i], len - pos);
4135 skb_shinfo(skb)->nr_frags++;
4136 }
4137 k++;
4138 } else
4139 skb_shinfo(skb)->nr_frags++;
4140 pos += size;
4141 }
4142 skb_shinfo(skb1)->nr_frags = k;
4143
4144 skb1->unreadable = skb->unreadable;
4145}
4146
4147/**
4148 * skb_split - Split fragmented skb to two parts at length len.
4149 * @skb: the buffer to split
4150 * @skb1: the buffer to receive the second part
4151 * @len: new length for skb
4152 */
4153void skb_split(struct sk_buff *skb, struct sk_buff *skb1, const u32 len)
4154{
4155 int pos = skb_headlen(skb);
4156 const int zc_flags = SKBFL_SHARED_FRAG | SKBFL_PURE_ZEROCOPY;
4157
4158 skb_zcopy_downgrade_managed(skb);
4159
4160 skb_shinfo(skb1)->flags |= skb_shinfo(skb)->flags & zc_flags;
4161 skb_zerocopy_clone(skb1, skb, 0);
4162 if (len < pos) /* Split line is inside header. */
4163 skb_split_inside_header(skb, skb1, len, pos);
4164 else /* Second chunk has no header, nothing to copy. */
4165 skb_split_no_header(skb, skb1, len, pos);
4166}
4167EXPORT_SYMBOL(skb_split);
4168
4169/* Shifting from/to a cloned skb is a no-go.
4170 *
4171 * Caller cannot keep skb_shinfo related pointers past calling here!
4172 */
4173static int skb_prepare_for_shift(struct sk_buff *skb)
4174{
4175 return skb_unclone_keeptruesize(skb, GFP_ATOMIC);
4176}
4177
4178/**
4179 * skb_shift - Shifts paged data partially from skb to another
4180 * @tgt: buffer into which tail data gets added
4181 * @skb: buffer from which the paged data comes from
4182 * @shiftlen: shift up to this many bytes
4183 *
4184 * Attempts to shift up to shiftlen worth of bytes, which may be less than
4185 * the length of the skb, from skb to tgt. Returns number bytes shifted.
4186 * It's up to caller to free skb if everything was shifted.
4187 *
4188 * If @tgt runs out of frags, the whole operation is aborted.
4189 *
4190 * Skb cannot include anything else but paged data while tgt is allowed
4191 * to have non-paged data as well.
4192 *
4193 * TODO: full sized shift could be optimized but that would need
4194 * specialized skb free'er to handle frags without up-to-date nr_frags.
4195 */
4196int skb_shift(struct sk_buff *tgt, struct sk_buff *skb, int shiftlen)
4197{
4198 int from, to, merge, todo;
4199 skb_frag_t *fragfrom, *fragto;
4200
4201 BUG_ON(shiftlen > skb->len);
4202
4203 if (skb_headlen(skb))
4204 return 0;
4205 if (skb_zcopy(tgt) || skb_zcopy(skb))
4206 return 0;
4207
4208 DEBUG_NET_WARN_ON_ONCE(tgt->pp_recycle != skb->pp_recycle);
4209 DEBUG_NET_WARN_ON_ONCE(skb_cmp_decrypted(tgt, skb));
4210
4211 todo = shiftlen;
4212 from = 0;
4213 to = skb_shinfo(tgt)->nr_frags;
4214 fragfrom = &skb_shinfo(skb)->frags[from];
4215
4216 /* Actual merge is delayed until the point when we know we can
4217 * commit all, so that we don't have to undo partial changes
4218 */
4219 if (!skb_can_coalesce(tgt, to, skb_frag_page(fragfrom),
4220 skb_frag_off(fragfrom))) {
4221 merge = -1;
4222 } else {
4223 merge = to - 1;
4224
4225 todo -= skb_frag_size(fragfrom);
4226 if (todo < 0) {
4227 if (skb_prepare_for_shift(skb) ||
4228 skb_prepare_for_shift(tgt))
4229 return 0;
4230
4231 /* All previous frag pointers might be stale! */
4232 fragfrom = &skb_shinfo(skb)->frags[from];
4233 fragto = &skb_shinfo(tgt)->frags[merge];
4234
4235 skb_frag_size_add(fragto, shiftlen);
4236 skb_frag_size_sub(fragfrom, shiftlen);
4237 skb_frag_off_add(fragfrom, shiftlen);
4238
4239 goto onlymerged;
4240 }
4241
4242 from++;
4243 }
4244
4245 /* Skip full, not-fitting skb to avoid expensive operations */
4246 if ((shiftlen == skb->len) &&
4247 (skb_shinfo(skb)->nr_frags - from) > (MAX_SKB_FRAGS - to))
4248 return 0;
4249
4250 if (skb_prepare_for_shift(skb) || skb_prepare_for_shift(tgt))
4251 return 0;
4252
4253 while ((todo > 0) && (from < skb_shinfo(skb)->nr_frags)) {
4254 if (to == MAX_SKB_FRAGS)
4255 return 0;
4256
4257 fragfrom = &skb_shinfo(skb)->frags[from];
4258 fragto = &skb_shinfo(tgt)->frags[to];
4259
4260 if (todo >= skb_frag_size(fragfrom)) {
4261 *fragto = *fragfrom;
4262 todo -= skb_frag_size(fragfrom);
4263 from++;
4264 to++;
4265
4266 } else {
4267 __skb_frag_ref(fragfrom);
4268 skb_frag_page_copy(fragto, fragfrom);
4269 skb_frag_off_copy(fragto, fragfrom);
4270 skb_frag_size_set(fragto, todo);
4271
4272 skb_frag_off_add(fragfrom, todo);
4273 skb_frag_size_sub(fragfrom, todo);
4274 todo = 0;
4275
4276 to++;
4277 break;
4278 }
4279 }
4280
4281 /* Ready to "commit" this state change to tgt */
4282 skb_shinfo(tgt)->nr_frags = to;
4283
4284 if (merge >= 0) {
4285 fragfrom = &skb_shinfo(skb)->frags[0];
4286 fragto = &skb_shinfo(tgt)->frags[merge];
4287
4288 skb_frag_size_add(fragto, skb_frag_size(fragfrom));
4289 __skb_frag_unref(fragfrom, skb->pp_recycle);
4290 }
4291
4292 /* Reposition in the original skb */
4293 to = 0;
4294 while (from < skb_shinfo(skb)->nr_frags)
4295 skb_shinfo(skb)->frags[to++] = skb_shinfo(skb)->frags[from++];
4296 skb_shinfo(skb)->nr_frags = to;
4297
4298 BUG_ON(todo > 0 && !skb_shinfo(skb)->nr_frags);
4299
4300onlymerged:
4301 /* Most likely the tgt won't ever need its checksum anymore, skb on
4302 * the other hand might need it if it needs to be resent
4303 */
4304 tgt->ip_summed = CHECKSUM_PARTIAL;
4305 skb->ip_summed = CHECKSUM_PARTIAL;
4306
4307 skb_len_add(skb, -shiftlen);
4308 skb_len_add(tgt, shiftlen);
4309
4310 return shiftlen;
4311}
4312
4313/**
4314 * skb_prepare_seq_read - Prepare a sequential read of skb data
4315 * @skb: the buffer to read
4316 * @from: lower offset of data to be read
4317 * @to: upper offset of data to be read
4318 * @st: state variable
4319 *
4320 * Initializes the specified state variable. Must be called before
4321 * invoking skb_seq_read() for the first time.
4322 */
4323void skb_prepare_seq_read(struct sk_buff *skb, unsigned int from,
4324 unsigned int to, struct skb_seq_state *st)
4325{
4326 st->lower_offset = from;
4327 st->upper_offset = to;
4328 st->root_skb = st->cur_skb = skb;
4329 st->frag_idx = st->stepped_offset = 0;
4330 st->frag_data = NULL;
4331 st->frag_off = 0;
4332}
4333EXPORT_SYMBOL(skb_prepare_seq_read);
4334
4335/**
4336 * skb_seq_read - Sequentially read skb data
4337 * @consumed: number of bytes consumed by the caller so far
4338 * @data: destination pointer for data to be returned
4339 * @st: state variable
4340 *
4341 * Reads a block of skb data at @consumed relative to the
4342 * lower offset specified to skb_prepare_seq_read(). Assigns
4343 * the head of the data block to @data and returns the length
4344 * of the block or 0 if the end of the skb data or the upper
4345 * offset has been reached.
4346 *
4347 * The caller is not required to consume all of the data
4348 * returned, i.e. @consumed is typically set to the number
4349 * of bytes already consumed and the next call to
4350 * skb_seq_read() will return the remaining part of the block.
4351 *
4352 * Note 1: The size of each block of data returned can be arbitrary,
4353 * this limitation is the cost for zerocopy sequential
4354 * reads of potentially non linear data.
4355 *
4356 * Note 2: Fragment lists within fragments are not implemented
4357 * at the moment, state->root_skb could be replaced with
4358 * a stack for this purpose.
4359 */
4360unsigned int skb_seq_read(unsigned int consumed, const u8 **data,
4361 struct skb_seq_state *st)
4362{
4363 unsigned int block_limit, abs_offset = consumed + st->lower_offset;
4364 skb_frag_t *frag;
4365
4366 if (unlikely(abs_offset >= st->upper_offset)) {
4367 if (st->frag_data) {
4368 kunmap_atomic(st->frag_data);
4369 st->frag_data = NULL;
4370 }
4371 return 0;
4372 }
4373
4374next_skb:
4375 block_limit = skb_headlen(st->cur_skb) + st->stepped_offset;
4376
4377 if (abs_offset < block_limit && !st->frag_data) {
4378 *data = st->cur_skb->data + (abs_offset - st->stepped_offset);
4379 return block_limit - abs_offset;
4380 }
4381
4382 if (!skb_frags_readable(st->cur_skb))
4383 return 0;
4384
4385 if (st->frag_idx == 0 && !st->frag_data)
4386 st->stepped_offset += skb_headlen(st->cur_skb);
4387
4388 while (st->frag_idx < skb_shinfo(st->cur_skb)->nr_frags) {
4389 unsigned int pg_idx, pg_off, pg_sz;
4390
4391 frag = &skb_shinfo(st->cur_skb)->frags[st->frag_idx];
4392
4393 pg_idx = 0;
4394 pg_off = skb_frag_off(frag);
4395 pg_sz = skb_frag_size(frag);
4396
4397 if (skb_frag_must_loop(skb_frag_page(frag))) {
4398 pg_idx = (pg_off + st->frag_off) >> PAGE_SHIFT;
4399 pg_off = offset_in_page(pg_off + st->frag_off);
4400 pg_sz = min_t(unsigned int, pg_sz - st->frag_off,
4401 PAGE_SIZE - pg_off);
4402 }
4403
4404 block_limit = pg_sz + st->stepped_offset;
4405 if (abs_offset < block_limit) {
4406 if (!st->frag_data)
4407 st->frag_data = kmap_atomic(skb_frag_page(frag) + pg_idx);
4408
4409 *data = (u8 *)st->frag_data + pg_off +
4410 (abs_offset - st->stepped_offset);
4411
4412 return block_limit - abs_offset;
4413 }
4414
4415 if (st->frag_data) {
4416 kunmap_atomic(st->frag_data);
4417 st->frag_data = NULL;
4418 }
4419
4420 st->stepped_offset += pg_sz;
4421 st->frag_off += pg_sz;
4422 if (st->frag_off == skb_frag_size(frag)) {
4423 st->frag_off = 0;
4424 st->frag_idx++;
4425 }
4426 }
4427
4428 if (st->frag_data) {
4429 kunmap_atomic(st->frag_data);
4430 st->frag_data = NULL;
4431 }
4432
4433 if (st->root_skb == st->cur_skb && skb_has_frag_list(st->root_skb)) {
4434 st->cur_skb = skb_shinfo(st->root_skb)->frag_list;
4435 st->frag_idx = 0;
4436 goto next_skb;
4437 } else if (st->cur_skb->next) {
4438 st->cur_skb = st->cur_skb->next;
4439 st->frag_idx = 0;
4440 goto next_skb;
4441 }
4442
4443 return 0;
4444}
4445EXPORT_SYMBOL(skb_seq_read);
4446
4447/**
4448 * skb_abort_seq_read - Abort a sequential read of skb data
4449 * @st: state variable
4450 *
4451 * Must be called if skb_seq_read() was not called until it
4452 * returned 0.
4453 */
4454void skb_abort_seq_read(struct skb_seq_state *st)
4455{
4456 if (st->frag_data)
4457 kunmap_atomic(st->frag_data);
4458}
4459EXPORT_SYMBOL(skb_abort_seq_read);
4460
4461/**
4462 * skb_copy_seq_read() - copy from a skb_seq_state to a buffer
4463 * @st: source skb_seq_state
4464 * @offset: offset in source
4465 * @to: destination buffer
4466 * @len: number of bytes to copy
4467 *
4468 * Copy @len bytes from @offset bytes into the source @st to the destination
4469 * buffer @to. `offset` should increase (or be unchanged) with each subsequent
4470 * call to this function. If offset needs to decrease from the previous use `st`
4471 * should be reset first.
4472 *
4473 * Return: 0 on success or -EINVAL if the copy ended early
4474 */
4475int skb_copy_seq_read(struct skb_seq_state *st, int offset, void *to, int len)
4476{
4477 const u8 *data;
4478 u32 sqlen;
4479
4480 for (;;) {
4481 sqlen = skb_seq_read(offset, &data, st);
4482 if (sqlen == 0)
4483 return -EINVAL;
4484 if (sqlen >= len) {
4485 memcpy(to, data, len);
4486 return 0;
4487 }
4488 memcpy(to, data, sqlen);
4489 to += sqlen;
4490 offset += sqlen;
4491 len -= sqlen;
4492 }
4493}
4494EXPORT_SYMBOL(skb_copy_seq_read);
4495
4496#define TS_SKB_CB(state) ((struct skb_seq_state *) &((state)->cb))
4497
4498static unsigned int skb_ts_get_next_block(unsigned int offset, const u8 **text,
4499 struct ts_config *conf,
4500 struct ts_state *state)
4501{
4502 return skb_seq_read(offset, text, TS_SKB_CB(state));
4503}
4504
4505static void skb_ts_finish(struct ts_config *conf, struct ts_state *state)
4506{
4507 skb_abort_seq_read(TS_SKB_CB(state));
4508}
4509
4510/**
4511 * skb_find_text - Find a text pattern in skb data
4512 * @skb: the buffer to look in
4513 * @from: search offset
4514 * @to: search limit
4515 * @config: textsearch configuration
4516 *
4517 * Finds a pattern in the skb data according to the specified
4518 * textsearch configuration. Use textsearch_next() to retrieve
4519 * subsequent occurrences of the pattern. Returns the offset
4520 * to the first occurrence or UINT_MAX if no match was found.
4521 */
4522unsigned int skb_find_text(struct sk_buff *skb, unsigned int from,
4523 unsigned int to, struct ts_config *config)
4524{
4525 unsigned int patlen = config->ops->get_pattern_len(config);
4526 struct ts_state state;
4527 unsigned int ret;
4528
4529 BUILD_BUG_ON(sizeof(struct skb_seq_state) > sizeof(state.cb));
4530
4531 config->get_next_block = skb_ts_get_next_block;
4532 config->finish = skb_ts_finish;
4533
4534 skb_prepare_seq_read(skb, from, to, TS_SKB_CB(&state));
4535
4536 ret = textsearch_find(config, &state);
4537 return (ret + patlen <= to - from ? ret : UINT_MAX);
4538}
4539EXPORT_SYMBOL(skb_find_text);
4540
4541int skb_append_pagefrags(struct sk_buff *skb, struct page *page,
4542 int offset, size_t size, size_t max_frags)
4543{
4544 int i = skb_shinfo(skb)->nr_frags;
4545
4546 if (skb_can_coalesce(skb, i, page, offset)) {
4547 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], size);
4548 } else if (i < max_frags) {
4549 skb_zcopy_downgrade_managed(skb);
4550 get_page(page);
4551 skb_fill_page_desc_noacc(skb, i, page, offset, size);
4552 } else {
4553 return -EMSGSIZE;
4554 }
4555
4556 return 0;
4557}
4558EXPORT_SYMBOL_GPL(skb_append_pagefrags);
4559
4560/**
4561 * skb_pull_rcsum - pull skb and update receive checksum
4562 * @skb: buffer to update
4563 * @len: length of data pulled
4564 *
4565 * This function performs an skb_pull on the packet and updates
4566 * the CHECKSUM_COMPLETE checksum. It should be used on
4567 * receive path processing instead of skb_pull unless you know
4568 * that the checksum difference is zero (e.g., a valid IP header)
4569 * or you are setting ip_summed to CHECKSUM_NONE.
4570 */
4571void *skb_pull_rcsum(struct sk_buff *skb, unsigned int len)
4572{
4573 unsigned char *data = skb->data;
4574
4575 BUG_ON(len > skb->len);
4576 __skb_pull(skb, len);
4577 skb_postpull_rcsum(skb, data, len);
4578 return skb->data;
4579}
4580EXPORT_SYMBOL_GPL(skb_pull_rcsum);
4581
4582static inline skb_frag_t skb_head_frag_to_page_desc(struct sk_buff *frag_skb)
4583{
4584 skb_frag_t head_frag;
4585 struct page *page;
4586
4587 page = virt_to_head_page(frag_skb->head);
4588 skb_frag_fill_page_desc(&head_frag, page, frag_skb->data -
4589 (unsigned char *)page_address(page),
4590 skb_headlen(frag_skb));
4591 return head_frag;
4592}
4593
4594struct sk_buff *skb_segment_list(struct sk_buff *skb,
4595 netdev_features_t features,
4596 unsigned int offset)
4597{
4598 struct sk_buff *list_skb = skb_shinfo(skb)->frag_list;
4599 unsigned int tnl_hlen = skb_tnl_header_len(skb);
4600 unsigned int delta_truesize = 0;
4601 unsigned int delta_len = 0;
4602 struct sk_buff *tail = NULL;
4603 struct sk_buff *nskb, *tmp;
4604 int len_diff, err;
4605
4606 skb_push(skb, -skb_network_offset(skb) + offset);
4607
4608 /* Ensure the head is writeable before touching the shared info */
4609 err = skb_unclone(skb, GFP_ATOMIC);
4610 if (err)
4611 goto err_linearize;
4612
4613 skb_shinfo(skb)->frag_list = NULL;
4614
4615 while (list_skb) {
4616 nskb = list_skb;
4617 list_skb = list_skb->next;
4618
4619 err = 0;
4620 delta_truesize += nskb->truesize;
4621 if (skb_shared(nskb)) {
4622 tmp = skb_clone(nskb, GFP_ATOMIC);
4623 if (tmp) {
4624 consume_skb(nskb);
4625 nskb = tmp;
4626 err = skb_unclone(nskb, GFP_ATOMIC);
4627 } else {
4628 err = -ENOMEM;
4629 }
4630 }
4631
4632 if (!tail)
4633 skb->next = nskb;
4634 else
4635 tail->next = nskb;
4636
4637 if (unlikely(err)) {
4638 nskb->next = list_skb;
4639 goto err_linearize;
4640 }
4641
4642 tail = nskb;
4643
4644 delta_len += nskb->len;
4645
4646 skb_push(nskb, -skb_network_offset(nskb) + offset);
4647
4648 skb_release_head_state(nskb);
4649 len_diff = skb_network_header_len(nskb) - skb_network_header_len(skb);
4650 __copy_skb_header(nskb, skb);
4651
4652 skb_headers_offset_update(nskb, skb_headroom(nskb) - skb_headroom(skb));
4653 nskb->transport_header += len_diff;
4654 skb_copy_from_linear_data_offset(skb, -tnl_hlen,
4655 nskb->data - tnl_hlen,
4656 offset + tnl_hlen);
4657
4658 if (skb_needs_linearize(nskb, features) &&
4659 __skb_linearize(nskb))
4660 goto err_linearize;
4661 }
4662
4663 skb->truesize = skb->truesize - delta_truesize;
4664 skb->data_len = skb->data_len - delta_len;
4665 skb->len = skb->len - delta_len;
4666
4667 skb_gso_reset(skb);
4668
4669 skb->prev = tail;
4670
4671 if (skb_needs_linearize(skb, features) &&
4672 __skb_linearize(skb))
4673 goto err_linearize;
4674
4675 skb_get(skb);
4676
4677 return skb;
4678
4679err_linearize:
4680 kfree_skb_list(skb->next);
4681 skb->next = NULL;
4682 return ERR_PTR(-ENOMEM);
4683}
4684EXPORT_SYMBOL_GPL(skb_segment_list);
4685
4686/**
4687 * skb_segment - Perform protocol segmentation on skb.
4688 * @head_skb: buffer to segment
4689 * @features: features for the output path (see dev->features)
4690 *
4691 * This function performs segmentation on the given skb. It returns
4692 * a pointer to the first in a list of new skbs for the segments.
4693 * In case of error it returns ERR_PTR(err).
4694 */
4695struct sk_buff *skb_segment(struct sk_buff *head_skb,
4696 netdev_features_t features)
4697{
4698 struct sk_buff *segs = NULL;
4699 struct sk_buff *tail = NULL;
4700 struct sk_buff *list_skb = skb_shinfo(head_skb)->frag_list;
4701 unsigned int mss = skb_shinfo(head_skb)->gso_size;
4702 unsigned int doffset = head_skb->data - skb_mac_header(head_skb);
4703 unsigned int offset = doffset;
4704 unsigned int tnl_hlen = skb_tnl_header_len(head_skb);
4705 unsigned int partial_segs = 0;
4706 unsigned int headroom;
4707 unsigned int len = head_skb->len;
4708 struct sk_buff *frag_skb;
4709 skb_frag_t *frag;
4710 __be16 proto;
4711 bool csum, sg;
4712 int err = -ENOMEM;
4713 int i = 0;
4714 int nfrags, pos;
4715
4716 if ((skb_shinfo(head_skb)->gso_type & SKB_GSO_DODGY) &&
4717 mss != GSO_BY_FRAGS && mss != skb_headlen(head_skb)) {
4718 struct sk_buff *check_skb;
4719
4720 for (check_skb = list_skb; check_skb; check_skb = check_skb->next) {
4721 if (skb_headlen(check_skb) && !check_skb->head_frag) {
4722 /* gso_size is untrusted, and we have a frag_list with
4723 * a linear non head_frag item.
4724 *
4725 * If head_skb's headlen does not fit requested gso_size,
4726 * it means that the frag_list members do NOT terminate
4727 * on exact gso_size boundaries. Hence we cannot perform
4728 * skb_frag_t page sharing. Therefore we must fallback to
4729 * copying the frag_list skbs; we do so by disabling SG.
4730 */
4731 features &= ~NETIF_F_SG;
4732 break;
4733 }
4734 }
4735 }
4736
4737 __skb_push(head_skb, doffset);
4738 proto = skb_network_protocol(head_skb, NULL);
4739 if (unlikely(!proto))
4740 return ERR_PTR(-EINVAL);
4741
4742 sg = !!(features & NETIF_F_SG);
4743 csum = !!can_checksum_protocol(features, proto);
4744
4745 if (sg && csum && (mss != GSO_BY_FRAGS)) {
4746 if (!(features & NETIF_F_GSO_PARTIAL)) {
4747 struct sk_buff *iter;
4748 unsigned int frag_len;
4749
4750 if (!list_skb ||
4751 !net_gso_ok(features, skb_shinfo(head_skb)->gso_type))
4752 goto normal;
4753
4754 /* If we get here then all the required
4755 * GSO features except frag_list are supported.
4756 * Try to split the SKB to multiple GSO SKBs
4757 * with no frag_list.
4758 * Currently we can do that only when the buffers don't
4759 * have a linear part and all the buffers except
4760 * the last are of the same length.
4761 */
4762 frag_len = list_skb->len;
4763 skb_walk_frags(head_skb, iter) {
4764 if (frag_len != iter->len && iter->next)
4765 goto normal;
4766 if (skb_headlen(iter) && !iter->head_frag)
4767 goto normal;
4768
4769 len -= iter->len;
4770 }
4771
4772 if (len != frag_len)
4773 goto normal;
4774 }
4775
4776 /* GSO partial only requires that we trim off any excess that
4777 * doesn't fit into an MSS sized block, so take care of that
4778 * now.
4779 * Cap len to not accidentally hit GSO_BY_FRAGS.
4780 */
4781 partial_segs = min(len, GSO_BY_FRAGS - 1) / mss;
4782 if (partial_segs > 1)
4783 mss *= partial_segs;
4784 else
4785 partial_segs = 0;
4786 }
4787
4788normal:
4789 headroom = skb_headroom(head_skb);
4790 pos = skb_headlen(head_skb);
4791
4792 if (skb_orphan_frags(head_skb, GFP_ATOMIC))
4793 return ERR_PTR(-ENOMEM);
4794
4795 nfrags = skb_shinfo(head_skb)->nr_frags;
4796 frag = skb_shinfo(head_skb)->frags;
4797 frag_skb = head_skb;
4798
4799 do {
4800 struct sk_buff *nskb;
4801 skb_frag_t *nskb_frag;
4802 int hsize;
4803 int size;
4804
4805 if (unlikely(mss == GSO_BY_FRAGS)) {
4806 len = list_skb->len;
4807 } else {
4808 len = head_skb->len - offset;
4809 if (len > mss)
4810 len = mss;
4811 }
4812
4813 hsize = skb_headlen(head_skb) - offset;
4814
4815 if (hsize <= 0 && i >= nfrags && skb_headlen(list_skb) &&
4816 (skb_headlen(list_skb) == len || sg)) {
4817 BUG_ON(skb_headlen(list_skb) > len);
4818
4819 nskb = skb_clone(list_skb, GFP_ATOMIC);
4820 if (unlikely(!nskb))
4821 goto err;
4822
4823 i = 0;
4824 nfrags = skb_shinfo(list_skb)->nr_frags;
4825 frag = skb_shinfo(list_skb)->frags;
4826 frag_skb = list_skb;
4827 pos += skb_headlen(list_skb);
4828
4829 while (pos < offset + len) {
4830 BUG_ON(i >= nfrags);
4831
4832 size = skb_frag_size(frag);
4833 if (pos + size > offset + len)
4834 break;
4835
4836 i++;
4837 pos += size;
4838 frag++;
4839 }
4840
4841 list_skb = list_skb->next;
4842
4843 if (unlikely(pskb_trim(nskb, len))) {
4844 kfree_skb(nskb);
4845 goto err;
4846 }
4847
4848 hsize = skb_end_offset(nskb);
4849 if (skb_cow_head(nskb, doffset + headroom)) {
4850 kfree_skb(nskb);
4851 goto err;
4852 }
4853
4854 nskb->truesize += skb_end_offset(nskb) - hsize;
4855 skb_release_head_state(nskb);
4856 __skb_push(nskb, doffset);
4857 } else {
4858 if (hsize < 0)
4859 hsize = 0;
4860 if (hsize > len || !sg)
4861 hsize = len;
4862
4863 nskb = __alloc_skb(hsize + doffset + headroom,
4864 GFP_ATOMIC, skb_alloc_rx_flag(head_skb),
4865 NUMA_NO_NODE);
4866
4867 if (unlikely(!nskb))
4868 goto err;
4869
4870 skb_reserve(nskb, headroom);
4871 __skb_put(nskb, doffset);
4872 }
4873
4874 if (segs)
4875 tail->next = nskb;
4876 else
4877 segs = nskb;
4878 tail = nskb;
4879
4880 __copy_skb_header(nskb, head_skb);
4881
4882 skb_headers_offset_update(nskb, skb_headroom(nskb) - headroom);
4883 skb_reset_mac_len(nskb);
4884
4885 skb_copy_from_linear_data_offset(head_skb, -tnl_hlen,
4886 nskb->data - tnl_hlen,
4887 doffset + tnl_hlen);
4888
4889 if (nskb->len == len + doffset)
4890 goto perform_csum_check;
4891
4892 if (!sg) {
4893 if (!csum) {
4894 if (!nskb->remcsum_offload)
4895 nskb->ip_summed = CHECKSUM_NONE;
4896 SKB_GSO_CB(nskb)->csum =
4897 skb_copy_and_csum_bits(head_skb, offset,
4898 skb_put(nskb,
4899 len),
4900 len);
4901 SKB_GSO_CB(nskb)->csum_start =
4902 skb_headroom(nskb) + doffset;
4903 } else {
4904 if (skb_copy_bits(head_skb, offset, skb_put(nskb, len), len))
4905 goto err;
4906 }
4907 continue;
4908 }
4909
4910 nskb_frag = skb_shinfo(nskb)->frags;
4911
4912 skb_copy_from_linear_data_offset(head_skb, offset,
4913 skb_put(nskb, hsize), hsize);
4914
4915 skb_shinfo(nskb)->flags |= skb_shinfo(head_skb)->flags &
4916 SKBFL_SHARED_FRAG;
4917
4918 if (skb_zerocopy_clone(nskb, frag_skb, GFP_ATOMIC))
4919 goto err;
4920
4921 while (pos < offset + len) {
4922 if (i >= nfrags) {
4923 if (skb_orphan_frags(list_skb, GFP_ATOMIC) ||
4924 skb_zerocopy_clone(nskb, list_skb,
4925 GFP_ATOMIC))
4926 goto err;
4927
4928 i = 0;
4929 nfrags = skb_shinfo(list_skb)->nr_frags;
4930 frag = skb_shinfo(list_skb)->frags;
4931 frag_skb = list_skb;
4932 if (!skb_headlen(list_skb)) {
4933 BUG_ON(!nfrags);
4934 } else {
4935 BUG_ON(!list_skb->head_frag);
4936
4937 /* to make room for head_frag. */
4938 i--;
4939 frag--;
4940 }
4941
4942 list_skb = list_skb->next;
4943 }
4944
4945 if (unlikely(skb_shinfo(nskb)->nr_frags >=
4946 MAX_SKB_FRAGS)) {
4947 net_warn_ratelimited(
4948 "skb_segment: too many frags: %u %u\n",
4949 pos, mss);
4950 err = -EINVAL;
4951 goto err;
4952 }
4953
4954 *nskb_frag = (i < 0) ? skb_head_frag_to_page_desc(frag_skb) : *frag;
4955 __skb_frag_ref(nskb_frag);
4956 size = skb_frag_size(nskb_frag);
4957
4958 if (pos < offset) {
4959 skb_frag_off_add(nskb_frag, offset - pos);
4960 skb_frag_size_sub(nskb_frag, offset - pos);
4961 }
4962
4963 skb_shinfo(nskb)->nr_frags++;
4964
4965 if (pos + size <= offset + len) {
4966 i++;
4967 frag++;
4968 pos += size;
4969 } else {
4970 skb_frag_size_sub(nskb_frag, pos + size - (offset + len));
4971 goto skip_fraglist;
4972 }
4973
4974 nskb_frag++;
4975 }
4976
4977skip_fraglist:
4978 nskb->data_len = len - hsize;
4979 nskb->len += nskb->data_len;
4980 nskb->truesize += nskb->data_len;
4981
4982perform_csum_check:
4983 if (!csum) {
4984 if (skb_has_shared_frag(nskb) &&
4985 __skb_linearize(nskb))
4986 goto err;
4987
4988 if (!nskb->remcsum_offload)
4989 nskb->ip_summed = CHECKSUM_NONE;
4990 SKB_GSO_CB(nskb)->csum =
4991 skb_checksum(nskb, doffset,
4992 nskb->len - doffset, 0);
4993 SKB_GSO_CB(nskb)->csum_start =
4994 skb_headroom(nskb) + doffset;
4995 }
4996 } while ((offset += len) < head_skb->len);
4997
4998 /* Some callers want to get the end of the list.
4999 * Put it in segs->prev to avoid walking the list.
5000 * (see validate_xmit_skb_list() for example)
5001 */
5002 segs->prev = tail;
5003
5004 if (partial_segs) {
5005 struct sk_buff *iter;
5006 int type = skb_shinfo(head_skb)->gso_type;
5007 unsigned short gso_size = skb_shinfo(head_skb)->gso_size;
5008
5009 /* Update type to add partial and then remove dodgy if set */
5010 type |= (features & NETIF_F_GSO_PARTIAL) / NETIF_F_GSO_PARTIAL * SKB_GSO_PARTIAL;
5011 type &= ~SKB_GSO_DODGY;
5012
5013 /* Update GSO info and prepare to start updating headers on
5014 * our way back down the stack of protocols.
5015 */
5016 for (iter = segs; iter; iter = iter->next) {
5017 skb_shinfo(iter)->gso_size = gso_size;
5018 skb_shinfo(iter)->gso_segs = partial_segs;
5019 skb_shinfo(iter)->gso_type = type;
5020 SKB_GSO_CB(iter)->data_offset = skb_headroom(iter) + doffset;
5021 }
5022
5023 if (tail->len - doffset <= gso_size)
5024 skb_shinfo(tail)->gso_size = 0;
5025 else if (tail != segs)
5026 skb_shinfo(tail)->gso_segs = DIV_ROUND_UP(tail->len - doffset, gso_size);
5027 }
5028
5029 /* Following permits correct backpressure, for protocols
5030 * using skb_set_owner_w().
5031 * Idea is to tranfert ownership from head_skb to last segment.
5032 */
5033 if (head_skb->destructor == sock_wfree) {
5034 swap(tail->truesize, head_skb->truesize);
5035 swap(tail->destructor, head_skb->destructor);
5036 swap(tail->sk, head_skb->sk);
5037 }
5038 return segs;
5039
5040err:
5041 kfree_skb_list(segs);
5042 return ERR_PTR(err);
5043}
5044EXPORT_SYMBOL_GPL(skb_segment);
5045
5046#ifdef CONFIG_SKB_EXTENSIONS
5047#define SKB_EXT_ALIGN_VALUE 8
5048#define SKB_EXT_CHUNKSIZEOF(x) (ALIGN((sizeof(x)), SKB_EXT_ALIGN_VALUE) / SKB_EXT_ALIGN_VALUE)
5049
5050static const u8 skb_ext_type_len[] = {
5051#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
5052 [SKB_EXT_BRIDGE_NF] = SKB_EXT_CHUNKSIZEOF(struct nf_bridge_info),
5053#endif
5054#ifdef CONFIG_XFRM
5055 [SKB_EXT_SEC_PATH] = SKB_EXT_CHUNKSIZEOF(struct sec_path),
5056#endif
5057#if IS_ENABLED(CONFIG_NET_TC_SKB_EXT)
5058 [TC_SKB_EXT] = SKB_EXT_CHUNKSIZEOF(struct tc_skb_ext),
5059#endif
5060#if IS_ENABLED(CONFIG_MPTCP)
5061 [SKB_EXT_MPTCP] = SKB_EXT_CHUNKSIZEOF(struct mptcp_ext),
5062#endif
5063#if IS_ENABLED(CONFIG_MCTP_FLOWS)
5064 [SKB_EXT_MCTP] = SKB_EXT_CHUNKSIZEOF(struct mctp_flow),
5065#endif
5066};
5067
5068static __always_inline unsigned int skb_ext_total_length(void)
5069{
5070 unsigned int l = SKB_EXT_CHUNKSIZEOF(struct skb_ext);
5071 int i;
5072
5073 for (i = 0; i < ARRAY_SIZE(skb_ext_type_len); i++)
5074 l += skb_ext_type_len[i];
5075
5076 return l;
5077}
5078
5079static void skb_extensions_init(void)
5080{
5081 BUILD_BUG_ON(SKB_EXT_NUM >= 8);
5082#if !IS_ENABLED(CONFIG_KCOV_INSTRUMENT_ALL)
5083 BUILD_BUG_ON(skb_ext_total_length() > 255);
5084#endif
5085
5086 skbuff_ext_cache = kmem_cache_create("skbuff_ext_cache",
5087 SKB_EXT_ALIGN_VALUE * skb_ext_total_length(),
5088 0,
5089 SLAB_HWCACHE_ALIGN|SLAB_PANIC,
5090 NULL);
5091}
5092#else
5093static void skb_extensions_init(void) {}
5094#endif
5095
5096/* The SKB kmem_cache slab is critical for network performance. Never
5097 * merge/alias the slab with similar sized objects. This avoids fragmentation
5098 * that hurts performance of kmem_cache_{alloc,free}_bulk APIs.
5099 */
5100#ifndef CONFIG_SLUB_TINY
5101#define FLAG_SKB_NO_MERGE SLAB_NO_MERGE
5102#else /* CONFIG_SLUB_TINY - simple loop in kmem_cache_alloc_bulk */
5103#define FLAG_SKB_NO_MERGE 0
5104#endif
5105
5106void __init skb_init(void)
5107{
5108 net_hotdata.skbuff_cache = kmem_cache_create_usercopy("skbuff_head_cache",
5109 sizeof(struct sk_buff),
5110 0,
5111 SLAB_HWCACHE_ALIGN|SLAB_PANIC|
5112 FLAG_SKB_NO_MERGE,
5113 offsetof(struct sk_buff, cb),
5114 sizeof_field(struct sk_buff, cb),
5115 NULL);
5116 net_hotdata.skbuff_fclone_cache = kmem_cache_create("skbuff_fclone_cache",
5117 sizeof(struct sk_buff_fclones),
5118 0,
5119 SLAB_HWCACHE_ALIGN|SLAB_PANIC,
5120 NULL);
5121 /* usercopy should only access first SKB_SMALL_HEAD_HEADROOM bytes.
5122 * struct skb_shared_info is located at the end of skb->head,
5123 * and should not be copied to/from user.
5124 */
5125 net_hotdata.skb_small_head_cache = kmem_cache_create_usercopy("skbuff_small_head",
5126 SKB_SMALL_HEAD_CACHE_SIZE,
5127 0,
5128 SLAB_HWCACHE_ALIGN | SLAB_PANIC,
5129 0,
5130 SKB_SMALL_HEAD_HEADROOM,
5131 NULL);
5132 skb_extensions_init();
5133}
5134
5135static int
5136__skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int len,
5137 unsigned int recursion_level)
5138{
5139 int start = skb_headlen(skb);
5140 int i, copy = start - offset;
5141 struct sk_buff *frag_iter;
5142 int elt = 0;
5143
5144 if (unlikely(recursion_level >= 24))
5145 return -EMSGSIZE;
5146
5147 if (copy > 0) {
5148 if (copy > len)
5149 copy = len;
5150 sg_set_buf(sg, skb->data + offset, copy);
5151 elt++;
5152 if ((len -= copy) == 0)
5153 return elt;
5154 offset += copy;
5155 }
5156
5157 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
5158 int end;
5159
5160 WARN_ON(start > offset + len);
5161
5162 end = start + skb_frag_size(&skb_shinfo(skb)->frags[i]);
5163 if ((copy = end - offset) > 0) {
5164 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
5165 if (unlikely(elt && sg_is_last(&sg[elt - 1])))
5166 return -EMSGSIZE;
5167
5168 if (copy > len)
5169 copy = len;
5170 sg_set_page(&sg[elt], skb_frag_page(frag), copy,
5171 skb_frag_off(frag) + offset - start);
5172 elt++;
5173 if (!(len -= copy))
5174 return elt;
5175 offset += copy;
5176 }
5177 start = end;
5178 }
5179
5180 skb_walk_frags(skb, frag_iter) {
5181 int end, ret;
5182
5183 WARN_ON(start > offset + len);
5184
5185 end = start + frag_iter->len;
5186 if ((copy = end - offset) > 0) {
5187 if (unlikely(elt && sg_is_last(&sg[elt - 1])))
5188 return -EMSGSIZE;
5189
5190 if (copy > len)
5191 copy = len;
5192 ret = __skb_to_sgvec(frag_iter, sg+elt, offset - start,
5193 copy, recursion_level + 1);
5194 if (unlikely(ret < 0))
5195 return ret;
5196 elt += ret;
5197 if ((len -= copy) == 0)
5198 return elt;
5199 offset += copy;
5200 }
5201 start = end;
5202 }
5203 BUG_ON(len);
5204 return elt;
5205}
5206
5207/**
5208 * skb_to_sgvec - Fill a scatter-gather list from a socket buffer
5209 * @skb: Socket buffer containing the buffers to be mapped
5210 * @sg: The scatter-gather list to map into
5211 * @offset: The offset into the buffer's contents to start mapping
5212 * @len: Length of buffer space to be mapped
5213 *
5214 * Fill the specified scatter-gather list with mappings/pointers into a
5215 * region of the buffer space attached to a socket buffer. Returns either
5216 * the number of scatterlist items used, or -EMSGSIZE if the contents
5217 * could not fit.
5218 */
5219int skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int len)
5220{
5221 int nsg = __skb_to_sgvec(skb, sg, offset, len, 0);
5222
5223 if (nsg <= 0)
5224 return nsg;
5225
5226 sg_mark_end(&sg[nsg - 1]);
5227
5228 return nsg;
5229}
5230EXPORT_SYMBOL_GPL(skb_to_sgvec);
5231
5232/* As compared with skb_to_sgvec, skb_to_sgvec_nomark only map skb to given
5233 * sglist without mark the sg which contain last skb data as the end.
5234 * So the caller can mannipulate sg list as will when padding new data after
5235 * the first call without calling sg_unmark_end to expend sg list.
5236 *
5237 * Scenario to use skb_to_sgvec_nomark:
5238 * 1. sg_init_table
5239 * 2. skb_to_sgvec_nomark(payload1)
5240 * 3. skb_to_sgvec_nomark(payload2)
5241 *
5242 * This is equivalent to:
5243 * 1. sg_init_table
5244 * 2. skb_to_sgvec(payload1)
5245 * 3. sg_unmark_end
5246 * 4. skb_to_sgvec(payload2)
5247 *
5248 * When mapping multiple payload conditionally, skb_to_sgvec_nomark
5249 * is more preferable.
5250 */
5251int skb_to_sgvec_nomark(struct sk_buff *skb, struct scatterlist *sg,
5252 int offset, int len)
5253{
5254 return __skb_to_sgvec(skb, sg, offset, len, 0);
5255}
5256EXPORT_SYMBOL_GPL(skb_to_sgvec_nomark);
5257
5258
5259
5260/**
5261 * skb_cow_data - Check that a socket buffer's data buffers are writable
5262 * @skb: The socket buffer to check.
5263 * @tailbits: Amount of trailing space to be added
5264 * @trailer: Returned pointer to the skb where the @tailbits space begins
5265 *
5266 * Make sure that the data buffers attached to a socket buffer are
5267 * writable. If they are not, private copies are made of the data buffers
5268 * and the socket buffer is set to use these instead.
5269 *
5270 * If @tailbits is given, make sure that there is space to write @tailbits
5271 * bytes of data beyond current end of socket buffer. @trailer will be
5272 * set to point to the skb in which this space begins.
5273 *
5274 * The number of scatterlist elements required to completely map the
5275 * COW'd and extended socket buffer will be returned.
5276 */
5277int skb_cow_data(struct sk_buff *skb, int tailbits, struct sk_buff **trailer)
5278{
5279 int copyflag;
5280 int elt;
5281 struct sk_buff *skb1, **skb_p;
5282
5283 /* If skb is cloned or its head is paged, reallocate
5284 * head pulling out all the pages (pages are considered not writable
5285 * at the moment even if they are anonymous).
5286 */
5287 if ((skb_cloned(skb) || skb_shinfo(skb)->nr_frags) &&
5288 !__pskb_pull_tail(skb, __skb_pagelen(skb)))
5289 return -ENOMEM;
5290
5291 /* Easy case. Most of packets will go this way. */
5292 if (!skb_has_frag_list(skb)) {
5293 /* A little of trouble, not enough of space for trailer.
5294 * This should not happen, when stack is tuned to generate
5295 * good frames. OK, on miss we reallocate and reserve even more
5296 * space, 128 bytes is fair. */
5297
5298 if (skb_tailroom(skb) < tailbits &&
5299 pskb_expand_head(skb, 0, tailbits-skb_tailroom(skb)+128, GFP_ATOMIC))
5300 return -ENOMEM;
5301
5302 /* Voila! */
5303 *trailer = skb;
5304 return 1;
5305 }
5306
5307 /* Misery. We are in troubles, going to mincer fragments... */
5308
5309 elt = 1;
5310 skb_p = &skb_shinfo(skb)->frag_list;
5311 copyflag = 0;
5312
5313 while ((skb1 = *skb_p) != NULL) {
5314 int ntail = 0;
5315
5316 /* The fragment is partially pulled by someone,
5317 * this can happen on input. Copy it and everything
5318 * after it. */
5319
5320 if (skb_shared(skb1))
5321 copyflag = 1;
5322
5323 /* If the skb is the last, worry about trailer. */
5324
5325 if (skb1->next == NULL && tailbits) {
5326 if (skb_shinfo(skb1)->nr_frags ||
5327 skb_has_frag_list(skb1) ||
5328 skb_tailroom(skb1) < tailbits)
5329 ntail = tailbits + 128;
5330 }
5331
5332 if (copyflag ||
5333 skb_cloned(skb1) ||
5334 ntail ||
5335 skb_shinfo(skb1)->nr_frags ||
5336 skb_has_frag_list(skb1)) {
5337 struct sk_buff *skb2;
5338
5339 /* Fuck, we are miserable poor guys... */
5340 if (ntail == 0)
5341 skb2 = skb_copy(skb1, GFP_ATOMIC);
5342 else
5343 skb2 = skb_copy_expand(skb1,
5344 skb_headroom(skb1),
5345 ntail,
5346 GFP_ATOMIC);
5347 if (unlikely(skb2 == NULL))
5348 return -ENOMEM;
5349
5350 if (skb1->sk)
5351 skb_set_owner_w(skb2, skb1->sk);
5352
5353 /* Looking around. Are we still alive?
5354 * OK, link new skb, drop old one */
5355
5356 skb2->next = skb1->next;
5357 *skb_p = skb2;
5358 kfree_skb(skb1);
5359 skb1 = skb2;
5360 }
5361 elt++;
5362 *trailer = skb1;
5363 skb_p = &skb1->next;
5364 }
5365
5366 return elt;
5367}
5368EXPORT_SYMBOL_GPL(skb_cow_data);
5369
5370static void sock_rmem_free(struct sk_buff *skb)
5371{
5372 struct sock *sk = skb->sk;
5373
5374 atomic_sub(skb->truesize, &sk->sk_rmem_alloc);
5375}
5376
5377static void skb_set_err_queue(struct sk_buff *skb)
5378{
5379 /* pkt_type of skbs received on local sockets is never PACKET_OUTGOING.
5380 * So, it is safe to (mis)use it to mark skbs on the error queue.
5381 */
5382 skb->pkt_type = PACKET_OUTGOING;
5383 BUILD_BUG_ON(PACKET_OUTGOING == 0);
5384}
5385
5386/*
5387 * Note: We dont mem charge error packets (no sk_forward_alloc changes)
5388 */
5389int sock_queue_err_skb(struct sock *sk, struct sk_buff *skb)
5390{
5391 if (atomic_read(&sk->sk_rmem_alloc) + skb->truesize >=
5392 (unsigned int)READ_ONCE(sk->sk_rcvbuf))
5393 return -ENOMEM;
5394
5395 skb_orphan(skb);
5396 skb->sk = sk;
5397 skb->destructor = sock_rmem_free;
5398 atomic_add(skb->truesize, &sk->sk_rmem_alloc);
5399 skb_set_err_queue(skb);
5400
5401 /* before exiting rcu section, make sure dst is refcounted */
5402 skb_dst_force(skb);
5403
5404 skb_queue_tail(&sk->sk_error_queue, skb);
5405 if (!sock_flag(sk, SOCK_DEAD))
5406 sk_error_report(sk);
5407 return 0;
5408}
5409EXPORT_SYMBOL(sock_queue_err_skb);
5410
5411static bool is_icmp_err_skb(const struct sk_buff *skb)
5412{
5413 return skb && (SKB_EXT_ERR(skb)->ee.ee_origin == SO_EE_ORIGIN_ICMP ||
5414 SKB_EXT_ERR(skb)->ee.ee_origin == SO_EE_ORIGIN_ICMP6);
5415}
5416
5417struct sk_buff *sock_dequeue_err_skb(struct sock *sk)
5418{
5419 struct sk_buff_head *q = &sk->sk_error_queue;
5420 struct sk_buff *skb, *skb_next = NULL;
5421 bool icmp_next = false;
5422 unsigned long flags;
5423
5424 if (skb_queue_empty_lockless(q))
5425 return NULL;
5426
5427 spin_lock_irqsave(&q->lock, flags);
5428 skb = __skb_dequeue(q);
5429 if (skb && (skb_next = skb_peek(q))) {
5430 icmp_next = is_icmp_err_skb(skb_next);
5431 if (icmp_next)
5432 sk->sk_err = SKB_EXT_ERR(skb_next)->ee.ee_errno;
5433 }
5434 spin_unlock_irqrestore(&q->lock, flags);
5435
5436 if (is_icmp_err_skb(skb) && !icmp_next)
5437 sk->sk_err = 0;
5438
5439 if (skb_next)
5440 sk_error_report(sk);
5441
5442 return skb;
5443}
5444EXPORT_SYMBOL(sock_dequeue_err_skb);
5445
5446/**
5447 * skb_clone_sk - create clone of skb, and take reference to socket
5448 * @skb: the skb to clone
5449 *
5450 * This function creates a clone of a buffer that holds a reference on
5451 * sk_refcnt. Buffers created via this function are meant to be
5452 * returned using sock_queue_err_skb, or free via kfree_skb.
5453 *
5454 * When passing buffers allocated with this function to sock_queue_err_skb
5455 * it is necessary to wrap the call with sock_hold/sock_put in order to
5456 * prevent the socket from being released prior to being enqueued on
5457 * the sk_error_queue.
5458 */
5459struct sk_buff *skb_clone_sk(struct sk_buff *skb)
5460{
5461 struct sock *sk = skb->sk;
5462 struct sk_buff *clone;
5463
5464 if (!sk || !refcount_inc_not_zero(&sk->sk_refcnt))
5465 return NULL;
5466
5467 clone = skb_clone(skb, GFP_ATOMIC);
5468 if (!clone) {
5469 sock_put(sk);
5470 return NULL;
5471 }
5472
5473 clone->sk = sk;
5474 clone->destructor = sock_efree;
5475
5476 return clone;
5477}
5478EXPORT_SYMBOL(skb_clone_sk);
5479
5480static void __skb_complete_tx_timestamp(struct sk_buff *skb,
5481 struct sock *sk,
5482 int tstype,
5483 bool opt_stats)
5484{
5485 struct sock_exterr_skb *serr;
5486 int err;
5487
5488 BUILD_BUG_ON(sizeof(struct sock_exterr_skb) > sizeof(skb->cb));
5489
5490 serr = SKB_EXT_ERR(skb);
5491 memset(serr, 0, sizeof(*serr));
5492 serr->ee.ee_errno = ENOMSG;
5493 serr->ee.ee_origin = SO_EE_ORIGIN_TIMESTAMPING;
5494 serr->ee.ee_info = tstype;
5495 serr->opt_stats = opt_stats;
5496 serr->header.h4.iif = skb->dev ? skb->dev->ifindex : 0;
5497 if (READ_ONCE(sk->sk_tsflags) & SOF_TIMESTAMPING_OPT_ID) {
5498 serr->ee.ee_data = skb_shinfo(skb)->tskey;
5499 if (sk_is_tcp(sk))
5500 serr->ee.ee_data -= atomic_read(&sk->sk_tskey);
5501 }
5502
5503 err = sock_queue_err_skb(sk, skb);
5504
5505 if (err)
5506 kfree_skb(skb);
5507}
5508
5509static bool skb_may_tx_timestamp(struct sock *sk, bool tsonly)
5510{
5511 bool ret;
5512
5513 if (likely(tsonly || READ_ONCE(sock_net(sk)->core.sysctl_tstamp_allow_data)))
5514 return true;
5515
5516 read_lock_bh(&sk->sk_callback_lock);
5517 ret = sk->sk_socket && sk->sk_socket->file &&
5518 file_ns_capable(sk->sk_socket->file, &init_user_ns, CAP_NET_RAW);
5519 read_unlock_bh(&sk->sk_callback_lock);
5520 return ret;
5521}
5522
5523void skb_complete_tx_timestamp(struct sk_buff *skb,
5524 struct skb_shared_hwtstamps *hwtstamps)
5525{
5526 struct sock *sk = skb->sk;
5527
5528 if (!skb_may_tx_timestamp(sk, false))
5529 goto err;
5530
5531 /* Take a reference to prevent skb_orphan() from freeing the socket,
5532 * but only if the socket refcount is not zero.
5533 */
5534 if (likely(refcount_inc_not_zero(&sk->sk_refcnt))) {
5535 *skb_hwtstamps(skb) = *hwtstamps;
5536 __skb_complete_tx_timestamp(skb, sk, SCM_TSTAMP_SND, false);
5537 sock_put(sk);
5538 return;
5539 }
5540
5541err:
5542 kfree_skb(skb);
5543}
5544EXPORT_SYMBOL_GPL(skb_complete_tx_timestamp);
5545
5546void __skb_tstamp_tx(struct sk_buff *orig_skb,
5547 const struct sk_buff *ack_skb,
5548 struct skb_shared_hwtstamps *hwtstamps,
5549 struct sock *sk, int tstype)
5550{
5551 struct sk_buff *skb;
5552 bool tsonly, opt_stats = false;
5553 u32 tsflags;
5554
5555 if (!sk)
5556 return;
5557
5558 tsflags = READ_ONCE(sk->sk_tsflags);
5559 if (!hwtstamps && !(tsflags & SOF_TIMESTAMPING_OPT_TX_SWHW) &&
5560 skb_shinfo(orig_skb)->tx_flags & SKBTX_IN_PROGRESS)
5561 return;
5562
5563 tsonly = tsflags & SOF_TIMESTAMPING_OPT_TSONLY;
5564 if (!skb_may_tx_timestamp(sk, tsonly))
5565 return;
5566
5567 if (tsonly) {
5568#ifdef CONFIG_INET
5569 if ((tsflags & SOF_TIMESTAMPING_OPT_STATS) &&
5570 sk_is_tcp(sk)) {
5571 skb = tcp_get_timestamping_opt_stats(sk, orig_skb,
5572 ack_skb);
5573 opt_stats = true;
5574 } else
5575#endif
5576 skb = alloc_skb(0, GFP_ATOMIC);
5577 } else {
5578 skb = skb_clone(orig_skb, GFP_ATOMIC);
5579
5580 if (skb_orphan_frags_rx(skb, GFP_ATOMIC)) {
5581 kfree_skb(skb);
5582 return;
5583 }
5584 }
5585 if (!skb)
5586 return;
5587
5588 if (tsonly) {
5589 skb_shinfo(skb)->tx_flags |= skb_shinfo(orig_skb)->tx_flags &
5590 SKBTX_ANY_TSTAMP;
5591 skb_shinfo(skb)->tskey = skb_shinfo(orig_skb)->tskey;
5592 }
5593
5594 if (hwtstamps)
5595 *skb_hwtstamps(skb) = *hwtstamps;
5596 else
5597 __net_timestamp(skb);
5598
5599 __skb_complete_tx_timestamp(skb, sk, tstype, opt_stats);
5600}
5601EXPORT_SYMBOL_GPL(__skb_tstamp_tx);
5602
5603void skb_tstamp_tx(struct sk_buff *orig_skb,
5604 struct skb_shared_hwtstamps *hwtstamps)
5605{
5606 return __skb_tstamp_tx(orig_skb, NULL, hwtstamps, orig_skb->sk,
5607 SCM_TSTAMP_SND);
5608}
5609EXPORT_SYMBOL_GPL(skb_tstamp_tx);
5610
5611#ifdef CONFIG_WIRELESS
5612void skb_complete_wifi_ack(struct sk_buff *skb, bool acked)
5613{
5614 struct sock *sk = skb->sk;
5615 struct sock_exterr_skb *serr;
5616 int err = 1;
5617
5618 skb->wifi_acked_valid = 1;
5619 skb->wifi_acked = acked;
5620
5621 serr = SKB_EXT_ERR(skb);
5622 memset(serr, 0, sizeof(*serr));
5623 serr->ee.ee_errno = ENOMSG;
5624 serr->ee.ee_origin = SO_EE_ORIGIN_TXSTATUS;
5625
5626 /* Take a reference to prevent skb_orphan() from freeing the socket,
5627 * but only if the socket refcount is not zero.
5628 */
5629 if (likely(refcount_inc_not_zero(&sk->sk_refcnt))) {
5630 err = sock_queue_err_skb(sk, skb);
5631 sock_put(sk);
5632 }
5633 if (err)
5634 kfree_skb(skb);
5635}
5636EXPORT_SYMBOL_GPL(skb_complete_wifi_ack);
5637#endif /* CONFIG_WIRELESS */
5638
5639/**
5640 * skb_partial_csum_set - set up and verify partial csum values for packet
5641 * @skb: the skb to set
5642 * @start: the number of bytes after skb->data to start checksumming.
5643 * @off: the offset from start to place the checksum.
5644 *
5645 * For untrusted partially-checksummed packets, we need to make sure the values
5646 * for skb->csum_start and skb->csum_offset are valid so we don't oops.
5647 *
5648 * This function checks and sets those values and skb->ip_summed: if this
5649 * returns false you should drop the packet.
5650 */
5651bool skb_partial_csum_set(struct sk_buff *skb, u16 start, u16 off)
5652{
5653 u32 csum_end = (u32)start + (u32)off + sizeof(__sum16);
5654 u32 csum_start = skb_headroom(skb) + (u32)start;
5655
5656 if (unlikely(csum_start >= U16_MAX || csum_end > skb_headlen(skb))) {
5657 net_warn_ratelimited("bad partial csum: csum=%u/%u headroom=%u headlen=%u\n",
5658 start, off, skb_headroom(skb), skb_headlen(skb));
5659 return false;
5660 }
5661 skb->ip_summed = CHECKSUM_PARTIAL;
5662 skb->csum_start = csum_start;
5663 skb->csum_offset = off;
5664 skb->transport_header = csum_start;
5665 return true;
5666}
5667EXPORT_SYMBOL_GPL(skb_partial_csum_set);
5668
5669static int skb_maybe_pull_tail(struct sk_buff *skb, unsigned int len,
5670 unsigned int max)
5671{
5672 if (skb_headlen(skb) >= len)
5673 return 0;
5674
5675 /* If we need to pullup then pullup to the max, so we
5676 * won't need to do it again.
5677 */
5678 if (max > skb->len)
5679 max = skb->len;
5680
5681 if (__pskb_pull_tail(skb, max - skb_headlen(skb)) == NULL)
5682 return -ENOMEM;
5683
5684 if (skb_headlen(skb) < len)
5685 return -EPROTO;
5686
5687 return 0;
5688}
5689
5690#define MAX_TCP_HDR_LEN (15 * 4)
5691
5692static __sum16 *skb_checksum_setup_ip(struct sk_buff *skb,
5693 typeof(IPPROTO_IP) proto,
5694 unsigned int off)
5695{
5696 int err;
5697
5698 switch (proto) {
5699 case IPPROTO_TCP:
5700 err = skb_maybe_pull_tail(skb, off + sizeof(struct tcphdr),
5701 off + MAX_TCP_HDR_LEN);
5702 if (!err && !skb_partial_csum_set(skb, off,
5703 offsetof(struct tcphdr,
5704 check)))
5705 err = -EPROTO;
5706 return err ? ERR_PTR(err) : &tcp_hdr(skb)->check;
5707
5708 case IPPROTO_UDP:
5709 err = skb_maybe_pull_tail(skb, off + sizeof(struct udphdr),
5710 off + sizeof(struct udphdr));
5711 if (!err && !skb_partial_csum_set(skb, off,
5712 offsetof(struct udphdr,
5713 check)))
5714 err = -EPROTO;
5715 return err ? ERR_PTR(err) : &udp_hdr(skb)->check;
5716 }
5717
5718 return ERR_PTR(-EPROTO);
5719}
5720
5721/* This value should be large enough to cover a tagged ethernet header plus
5722 * maximally sized IP and TCP or UDP headers.
5723 */
5724#define MAX_IP_HDR_LEN 128
5725
5726static int skb_checksum_setup_ipv4(struct sk_buff *skb, bool recalculate)
5727{
5728 unsigned int off;
5729 bool fragment;
5730 __sum16 *csum;
5731 int err;
5732
5733 fragment = false;
5734
5735 err = skb_maybe_pull_tail(skb,
5736 sizeof(struct iphdr),
5737 MAX_IP_HDR_LEN);
5738 if (err < 0)
5739 goto out;
5740
5741 if (ip_is_fragment(ip_hdr(skb)))
5742 fragment = true;
5743
5744 off = ip_hdrlen(skb);
5745
5746 err = -EPROTO;
5747
5748 if (fragment)
5749 goto out;
5750
5751 csum = skb_checksum_setup_ip(skb, ip_hdr(skb)->protocol, off);
5752 if (IS_ERR(csum))
5753 return PTR_ERR(csum);
5754
5755 if (recalculate)
5756 *csum = ~csum_tcpudp_magic(ip_hdr(skb)->saddr,
5757 ip_hdr(skb)->daddr,
5758 skb->len - off,
5759 ip_hdr(skb)->protocol, 0);
5760 err = 0;
5761
5762out:
5763 return err;
5764}
5765
5766/* This value should be large enough to cover a tagged ethernet header plus
5767 * an IPv6 header, all options, and a maximal TCP or UDP header.
5768 */
5769#define MAX_IPV6_HDR_LEN 256
5770
5771#define OPT_HDR(type, skb, off) \
5772 (type *)(skb_network_header(skb) + (off))
5773
5774static int skb_checksum_setup_ipv6(struct sk_buff *skb, bool recalculate)
5775{
5776 int err;
5777 u8 nexthdr;
5778 unsigned int off;
5779 unsigned int len;
5780 bool fragment;
5781 bool done;
5782 __sum16 *csum;
5783
5784 fragment = false;
5785 done = false;
5786
5787 off = sizeof(struct ipv6hdr);
5788
5789 err = skb_maybe_pull_tail(skb, off, MAX_IPV6_HDR_LEN);
5790 if (err < 0)
5791 goto out;
5792
5793 nexthdr = ipv6_hdr(skb)->nexthdr;
5794
5795 len = sizeof(struct ipv6hdr) + ntohs(ipv6_hdr(skb)->payload_len);
5796 while (off <= len && !done) {
5797 switch (nexthdr) {
5798 case IPPROTO_DSTOPTS:
5799 case IPPROTO_HOPOPTS:
5800 case IPPROTO_ROUTING: {
5801 struct ipv6_opt_hdr *hp;
5802
5803 err = skb_maybe_pull_tail(skb,
5804 off +
5805 sizeof(struct ipv6_opt_hdr),
5806 MAX_IPV6_HDR_LEN);
5807 if (err < 0)
5808 goto out;
5809
5810 hp = OPT_HDR(struct ipv6_opt_hdr, skb, off);
5811 nexthdr = hp->nexthdr;
5812 off += ipv6_optlen(hp);
5813 break;
5814 }
5815 case IPPROTO_AH: {
5816 struct ip_auth_hdr *hp;
5817
5818 err = skb_maybe_pull_tail(skb,
5819 off +
5820 sizeof(struct ip_auth_hdr),
5821 MAX_IPV6_HDR_LEN);
5822 if (err < 0)
5823 goto out;
5824
5825 hp = OPT_HDR(struct ip_auth_hdr, skb, off);
5826 nexthdr = hp->nexthdr;
5827 off += ipv6_authlen(hp);
5828 break;
5829 }
5830 case IPPROTO_FRAGMENT: {
5831 struct frag_hdr *hp;
5832
5833 err = skb_maybe_pull_tail(skb,
5834 off +
5835 sizeof(struct frag_hdr),
5836 MAX_IPV6_HDR_LEN);
5837 if (err < 0)
5838 goto out;
5839
5840 hp = OPT_HDR(struct frag_hdr, skb, off);
5841
5842 if (hp->frag_off & htons(IP6_OFFSET | IP6_MF))
5843 fragment = true;
5844
5845 nexthdr = hp->nexthdr;
5846 off += sizeof(struct frag_hdr);
5847 break;
5848 }
5849 default:
5850 done = true;
5851 break;
5852 }
5853 }
5854
5855 err = -EPROTO;
5856
5857 if (!done || fragment)
5858 goto out;
5859
5860 csum = skb_checksum_setup_ip(skb, nexthdr, off);
5861 if (IS_ERR(csum))
5862 return PTR_ERR(csum);
5863
5864 if (recalculate)
5865 *csum = ~csum_ipv6_magic(&ipv6_hdr(skb)->saddr,
5866 &ipv6_hdr(skb)->daddr,
5867 skb->len - off, nexthdr, 0);
5868 err = 0;
5869
5870out:
5871 return err;
5872}
5873
5874/**
5875 * skb_checksum_setup - set up partial checksum offset
5876 * @skb: the skb to set up
5877 * @recalculate: if true the pseudo-header checksum will be recalculated
5878 */
5879int skb_checksum_setup(struct sk_buff *skb, bool recalculate)
5880{
5881 int err;
5882
5883 switch (skb->protocol) {
5884 case htons(ETH_P_IP):
5885 err = skb_checksum_setup_ipv4(skb, recalculate);
5886 break;
5887
5888 case htons(ETH_P_IPV6):
5889 err = skb_checksum_setup_ipv6(skb, recalculate);
5890 break;
5891
5892 default:
5893 err = -EPROTO;
5894 break;
5895 }
5896
5897 return err;
5898}
5899EXPORT_SYMBOL(skb_checksum_setup);
5900
5901/**
5902 * skb_checksum_maybe_trim - maybe trims the given skb
5903 * @skb: the skb to check
5904 * @transport_len: the data length beyond the network header
5905 *
5906 * Checks whether the given skb has data beyond the given transport length.
5907 * If so, returns a cloned skb trimmed to this transport length.
5908 * Otherwise returns the provided skb. Returns NULL in error cases
5909 * (e.g. transport_len exceeds skb length or out-of-memory).
5910 *
5911 * Caller needs to set the skb transport header and free any returned skb if it
5912 * differs from the provided skb.
5913 */
5914static struct sk_buff *skb_checksum_maybe_trim(struct sk_buff *skb,
5915 unsigned int transport_len)
5916{
5917 struct sk_buff *skb_chk;
5918 unsigned int len = skb_transport_offset(skb) + transport_len;
5919 int ret;
5920
5921 if (skb->len < len)
5922 return NULL;
5923 else if (skb->len == len)
5924 return skb;
5925
5926 skb_chk = skb_clone(skb, GFP_ATOMIC);
5927 if (!skb_chk)
5928 return NULL;
5929
5930 ret = pskb_trim_rcsum(skb_chk, len);
5931 if (ret) {
5932 kfree_skb(skb_chk);
5933 return NULL;
5934 }
5935
5936 return skb_chk;
5937}
5938
5939/**
5940 * skb_checksum_trimmed - validate checksum of an skb
5941 * @skb: the skb to check
5942 * @transport_len: the data length beyond the network header
5943 * @skb_chkf: checksum function to use
5944 *
5945 * Applies the given checksum function skb_chkf to the provided skb.
5946 * Returns a checked and maybe trimmed skb. Returns NULL on error.
5947 *
5948 * If the skb has data beyond the given transport length, then a
5949 * trimmed & cloned skb is checked and returned.
5950 *
5951 * Caller needs to set the skb transport header and free any returned skb if it
5952 * differs from the provided skb.
5953 */
5954struct sk_buff *skb_checksum_trimmed(struct sk_buff *skb,
5955 unsigned int transport_len,
5956 __sum16(*skb_chkf)(struct sk_buff *skb))
5957{
5958 struct sk_buff *skb_chk;
5959 unsigned int offset = skb_transport_offset(skb);
5960 __sum16 ret;
5961
5962 skb_chk = skb_checksum_maybe_trim(skb, transport_len);
5963 if (!skb_chk)
5964 goto err;
5965
5966 if (!pskb_may_pull(skb_chk, offset))
5967 goto err;
5968
5969 skb_pull_rcsum(skb_chk, offset);
5970 ret = skb_chkf(skb_chk);
5971 skb_push_rcsum(skb_chk, offset);
5972
5973 if (ret)
5974 goto err;
5975
5976 return skb_chk;
5977
5978err:
5979 if (skb_chk && skb_chk != skb)
5980 kfree_skb(skb_chk);
5981
5982 return NULL;
5983
5984}
5985EXPORT_SYMBOL(skb_checksum_trimmed);
5986
5987void __skb_warn_lro_forwarding(const struct sk_buff *skb)
5988{
5989 net_warn_ratelimited("%s: received packets cannot be forwarded while LRO is enabled\n",
5990 skb->dev->name);
5991}
5992EXPORT_SYMBOL(__skb_warn_lro_forwarding);
5993
5994void kfree_skb_partial(struct sk_buff *skb, bool head_stolen)
5995{
5996 if (head_stolen) {
5997 skb_release_head_state(skb);
5998 kmem_cache_free(net_hotdata.skbuff_cache, skb);
5999 } else {
6000 __kfree_skb(skb);
6001 }
6002}
6003EXPORT_SYMBOL(kfree_skb_partial);
6004
6005/**
6006 * skb_try_coalesce - try to merge skb to prior one
6007 * @to: prior buffer
6008 * @from: buffer to add
6009 * @fragstolen: pointer to boolean
6010 * @delta_truesize: how much more was allocated than was requested
6011 */
6012bool skb_try_coalesce(struct sk_buff *to, struct sk_buff *from,
6013 bool *fragstolen, int *delta_truesize)
6014{
6015 struct skb_shared_info *to_shinfo, *from_shinfo;
6016 int i, delta, len = from->len;
6017
6018 *fragstolen = false;
6019
6020 if (skb_cloned(to))
6021 return false;
6022
6023 /* In general, avoid mixing page_pool and non-page_pool allocated
6024 * pages within the same SKB. In theory we could take full
6025 * references if @from is cloned and !@to->pp_recycle but its
6026 * tricky (due to potential race with the clone disappearing) and
6027 * rare, so not worth dealing with.
6028 */
6029 if (to->pp_recycle != from->pp_recycle)
6030 return false;
6031
6032 if (skb_frags_readable(from) != skb_frags_readable(to))
6033 return false;
6034
6035 if (len <= skb_tailroom(to) && skb_frags_readable(from)) {
6036 if (len)
6037 BUG_ON(skb_copy_bits(from, 0, skb_put(to, len), len));
6038 *delta_truesize = 0;
6039 return true;
6040 }
6041
6042 to_shinfo = skb_shinfo(to);
6043 from_shinfo = skb_shinfo(from);
6044 if (to_shinfo->frag_list || from_shinfo->frag_list)
6045 return false;
6046 if (skb_zcopy(to) || skb_zcopy(from))
6047 return false;
6048
6049 if (skb_headlen(from) != 0) {
6050 struct page *page;
6051 unsigned int offset;
6052
6053 if (to_shinfo->nr_frags +
6054 from_shinfo->nr_frags >= MAX_SKB_FRAGS)
6055 return false;
6056
6057 if (skb_head_is_locked(from))
6058 return false;
6059
6060 delta = from->truesize - SKB_DATA_ALIGN(sizeof(struct sk_buff));
6061
6062 page = virt_to_head_page(from->head);
6063 offset = from->data - (unsigned char *)page_address(page);
6064
6065 skb_fill_page_desc(to, to_shinfo->nr_frags,
6066 page, offset, skb_headlen(from));
6067 *fragstolen = true;
6068 } else {
6069 if (to_shinfo->nr_frags +
6070 from_shinfo->nr_frags > MAX_SKB_FRAGS)
6071 return false;
6072
6073 delta = from->truesize - SKB_TRUESIZE(skb_end_offset(from));
6074 }
6075
6076 WARN_ON_ONCE(delta < len);
6077
6078 memcpy(to_shinfo->frags + to_shinfo->nr_frags,
6079 from_shinfo->frags,
6080 from_shinfo->nr_frags * sizeof(skb_frag_t));
6081 to_shinfo->nr_frags += from_shinfo->nr_frags;
6082
6083 if (!skb_cloned(from))
6084 from_shinfo->nr_frags = 0;
6085
6086 /* if the skb is not cloned this does nothing
6087 * since we set nr_frags to 0.
6088 */
6089 if (skb_pp_frag_ref(from)) {
6090 for (i = 0; i < from_shinfo->nr_frags; i++)
6091 __skb_frag_ref(&from_shinfo->frags[i]);
6092 }
6093
6094 to->truesize += delta;
6095 to->len += len;
6096 to->data_len += len;
6097
6098 *delta_truesize = delta;
6099 return true;
6100}
6101EXPORT_SYMBOL(skb_try_coalesce);
6102
6103/**
6104 * skb_scrub_packet - scrub an skb
6105 *
6106 * @skb: buffer to clean
6107 * @xnet: packet is crossing netns
6108 *
6109 * skb_scrub_packet can be used after encapsulating or decapsulating a packet
6110 * into/from a tunnel. Some information have to be cleared during these
6111 * operations.
6112 * skb_scrub_packet can also be used to clean a skb before injecting it in
6113 * another namespace (@xnet == true). We have to clear all information in the
6114 * skb that could impact namespace isolation.
6115 */
6116void skb_scrub_packet(struct sk_buff *skb, bool xnet)
6117{
6118 skb->pkt_type = PACKET_HOST;
6119 skb->skb_iif = 0;
6120 skb->ignore_df = 0;
6121 skb_dst_drop(skb);
6122 skb_ext_reset(skb);
6123 nf_reset_ct(skb);
6124 nf_reset_trace(skb);
6125
6126#ifdef CONFIG_NET_SWITCHDEV
6127 skb->offload_fwd_mark = 0;
6128 skb->offload_l3_fwd_mark = 0;
6129#endif
6130 ipvs_reset(skb);
6131
6132 if (!xnet)
6133 return;
6134
6135 skb->mark = 0;
6136 skb_clear_tstamp(skb);
6137}
6138EXPORT_SYMBOL_GPL(skb_scrub_packet);
6139
6140static struct sk_buff *skb_reorder_vlan_header(struct sk_buff *skb)
6141{
6142 int mac_len, meta_len;
6143 void *meta;
6144
6145 if (skb_cow(skb, skb_headroom(skb)) < 0) {
6146 kfree_skb(skb);
6147 return NULL;
6148 }
6149
6150 mac_len = skb->data - skb_mac_header(skb);
6151 if (likely(mac_len > VLAN_HLEN + ETH_TLEN)) {
6152 memmove(skb_mac_header(skb) + VLAN_HLEN, skb_mac_header(skb),
6153 mac_len - VLAN_HLEN - ETH_TLEN);
6154 }
6155
6156 meta_len = skb_metadata_len(skb);
6157 if (meta_len) {
6158 meta = skb_metadata_end(skb) - meta_len;
6159 memmove(meta + VLAN_HLEN, meta, meta_len);
6160 }
6161
6162 skb->mac_header += VLAN_HLEN;
6163 return skb;
6164}
6165
6166struct sk_buff *skb_vlan_untag(struct sk_buff *skb)
6167{
6168 struct vlan_hdr *vhdr;
6169 u16 vlan_tci;
6170
6171 if (unlikely(skb_vlan_tag_present(skb))) {
6172 /* vlan_tci is already set-up so leave this for another time */
6173 return skb;
6174 }
6175
6176 skb = skb_share_check(skb, GFP_ATOMIC);
6177 if (unlikely(!skb))
6178 goto err_free;
6179 /* We may access the two bytes after vlan_hdr in vlan_set_encap_proto(). */
6180 if (unlikely(!pskb_may_pull(skb, VLAN_HLEN + sizeof(unsigned short))))
6181 goto err_free;
6182
6183 vhdr = (struct vlan_hdr *)skb->data;
6184 vlan_tci = ntohs(vhdr->h_vlan_TCI);
6185 __vlan_hwaccel_put_tag(skb, skb->protocol, vlan_tci);
6186
6187 skb_pull_rcsum(skb, VLAN_HLEN);
6188 vlan_set_encap_proto(skb, vhdr);
6189
6190 skb = skb_reorder_vlan_header(skb);
6191 if (unlikely(!skb))
6192 goto err_free;
6193
6194 skb_reset_network_header(skb);
6195 if (!skb_transport_header_was_set(skb))
6196 skb_reset_transport_header(skb);
6197 skb_reset_mac_len(skb);
6198
6199 return skb;
6200
6201err_free:
6202 kfree_skb(skb);
6203 return NULL;
6204}
6205EXPORT_SYMBOL(skb_vlan_untag);
6206
6207int skb_ensure_writable(struct sk_buff *skb, unsigned int write_len)
6208{
6209 if (!pskb_may_pull(skb, write_len))
6210 return -ENOMEM;
6211
6212 if (!skb_frags_readable(skb))
6213 return -EFAULT;
6214
6215 if (!skb_cloned(skb) || skb_clone_writable(skb, write_len))
6216 return 0;
6217
6218 return pskb_expand_head(skb, 0, 0, GFP_ATOMIC);
6219}
6220EXPORT_SYMBOL(skb_ensure_writable);
6221
6222int skb_ensure_writable_head_tail(struct sk_buff *skb, struct net_device *dev)
6223{
6224 int needed_headroom = dev->needed_headroom;
6225 int needed_tailroom = dev->needed_tailroom;
6226
6227 /* For tail taggers, we need to pad short frames ourselves, to ensure
6228 * that the tail tag does not fail at its role of being at the end of
6229 * the packet, once the conduit interface pads the frame. Account for
6230 * that pad length here, and pad later.
6231 */
6232 if (unlikely(needed_tailroom && skb->len < ETH_ZLEN))
6233 needed_tailroom += ETH_ZLEN - skb->len;
6234 /* skb_headroom() returns unsigned int... */
6235 needed_headroom = max_t(int, needed_headroom - skb_headroom(skb), 0);
6236 needed_tailroom = max_t(int, needed_tailroom - skb_tailroom(skb), 0);
6237
6238 if (likely(!needed_headroom && !needed_tailroom && !skb_cloned(skb)))
6239 /* No reallocation needed, yay! */
6240 return 0;
6241
6242 return pskb_expand_head(skb, needed_headroom, needed_tailroom,
6243 GFP_ATOMIC);
6244}
6245EXPORT_SYMBOL(skb_ensure_writable_head_tail);
6246
6247/* remove VLAN header from packet and update csum accordingly.
6248 * expects a non skb_vlan_tag_present skb with a vlan tag payload
6249 */
6250int __skb_vlan_pop(struct sk_buff *skb, u16 *vlan_tci)
6251{
6252 int offset = skb->data - skb_mac_header(skb);
6253 int err;
6254
6255 if (WARN_ONCE(offset,
6256 "__skb_vlan_pop got skb with skb->data not at mac header (offset %d)\n",
6257 offset)) {
6258 return -EINVAL;
6259 }
6260
6261 err = skb_ensure_writable(skb, VLAN_ETH_HLEN);
6262 if (unlikely(err))
6263 return err;
6264
6265 skb_postpull_rcsum(skb, skb->data + (2 * ETH_ALEN), VLAN_HLEN);
6266
6267 vlan_remove_tag(skb, vlan_tci);
6268
6269 skb->mac_header += VLAN_HLEN;
6270
6271 if (skb_network_offset(skb) < ETH_HLEN)
6272 skb_set_network_header(skb, ETH_HLEN);
6273
6274 skb_reset_mac_len(skb);
6275
6276 return err;
6277}
6278EXPORT_SYMBOL(__skb_vlan_pop);
6279
6280/* Pop a vlan tag either from hwaccel or from payload.
6281 * Expects skb->data at mac header.
6282 */
6283int skb_vlan_pop(struct sk_buff *skb)
6284{
6285 u16 vlan_tci;
6286 __be16 vlan_proto;
6287 int err;
6288
6289 if (likely(skb_vlan_tag_present(skb))) {
6290 __vlan_hwaccel_clear_tag(skb);
6291 } else {
6292 if (unlikely(!eth_type_vlan(skb->protocol)))
6293 return 0;
6294
6295 err = __skb_vlan_pop(skb, &vlan_tci);
6296 if (err)
6297 return err;
6298 }
6299 /* move next vlan tag to hw accel tag */
6300 if (likely(!eth_type_vlan(skb->protocol)))
6301 return 0;
6302
6303 vlan_proto = skb->protocol;
6304 err = __skb_vlan_pop(skb, &vlan_tci);
6305 if (unlikely(err))
6306 return err;
6307
6308 __vlan_hwaccel_put_tag(skb, vlan_proto, vlan_tci);
6309 return 0;
6310}
6311EXPORT_SYMBOL(skb_vlan_pop);
6312
6313/* Push a vlan tag either into hwaccel or into payload (if hwaccel tag present).
6314 * Expects skb->data at mac header.
6315 */
6316int skb_vlan_push(struct sk_buff *skb, __be16 vlan_proto, u16 vlan_tci)
6317{
6318 if (skb_vlan_tag_present(skb)) {
6319 int offset = skb->data - skb_mac_header(skb);
6320 int err;
6321
6322 if (WARN_ONCE(offset,
6323 "skb_vlan_push got skb with skb->data not at mac header (offset %d)\n",
6324 offset)) {
6325 return -EINVAL;
6326 }
6327
6328 err = __vlan_insert_tag(skb, skb->vlan_proto,
6329 skb_vlan_tag_get(skb));
6330 if (err)
6331 return err;
6332
6333 skb->protocol = skb->vlan_proto;
6334 skb->network_header -= VLAN_HLEN;
6335
6336 skb_postpush_rcsum(skb, skb->data + (2 * ETH_ALEN), VLAN_HLEN);
6337 }
6338 __vlan_hwaccel_put_tag(skb, vlan_proto, vlan_tci);
6339 return 0;
6340}
6341EXPORT_SYMBOL(skb_vlan_push);
6342
6343/**
6344 * skb_eth_pop() - Drop the Ethernet header at the head of a packet
6345 *
6346 * @skb: Socket buffer to modify
6347 *
6348 * Drop the Ethernet header of @skb.
6349 *
6350 * Expects that skb->data points to the mac header and that no VLAN tags are
6351 * present.
6352 *
6353 * Returns 0 on success, -errno otherwise.
6354 */
6355int skb_eth_pop(struct sk_buff *skb)
6356{
6357 if (!pskb_may_pull(skb, ETH_HLEN) || skb_vlan_tagged(skb) ||
6358 skb_network_offset(skb) < ETH_HLEN)
6359 return -EPROTO;
6360
6361 skb_pull_rcsum(skb, ETH_HLEN);
6362 skb_reset_mac_header(skb);
6363 skb_reset_mac_len(skb);
6364
6365 return 0;
6366}
6367EXPORT_SYMBOL(skb_eth_pop);
6368
6369/**
6370 * skb_eth_push() - Add a new Ethernet header at the head of a packet
6371 *
6372 * @skb: Socket buffer to modify
6373 * @dst: Destination MAC address of the new header
6374 * @src: Source MAC address of the new header
6375 *
6376 * Prepend @skb with a new Ethernet header.
6377 *
6378 * Expects that skb->data points to the mac header, which must be empty.
6379 *
6380 * Returns 0 on success, -errno otherwise.
6381 */
6382int skb_eth_push(struct sk_buff *skb, const unsigned char *dst,
6383 const unsigned char *src)
6384{
6385 struct ethhdr *eth;
6386 int err;
6387
6388 if (skb_network_offset(skb) || skb_vlan_tag_present(skb))
6389 return -EPROTO;
6390
6391 err = skb_cow_head(skb, sizeof(*eth));
6392 if (err < 0)
6393 return err;
6394
6395 skb_push(skb, sizeof(*eth));
6396 skb_reset_mac_header(skb);
6397 skb_reset_mac_len(skb);
6398
6399 eth = eth_hdr(skb);
6400 ether_addr_copy(eth->h_dest, dst);
6401 ether_addr_copy(eth->h_source, src);
6402 eth->h_proto = skb->protocol;
6403
6404 skb_postpush_rcsum(skb, eth, sizeof(*eth));
6405
6406 return 0;
6407}
6408EXPORT_SYMBOL(skb_eth_push);
6409
6410/* Update the ethertype of hdr and the skb csum value if required. */
6411static void skb_mod_eth_type(struct sk_buff *skb, struct ethhdr *hdr,
6412 __be16 ethertype)
6413{
6414 if (skb->ip_summed == CHECKSUM_COMPLETE) {
6415 __be16 diff[] = { ~hdr->h_proto, ethertype };
6416
6417 skb->csum = csum_partial((char *)diff, sizeof(diff), skb->csum);
6418 }
6419
6420 hdr->h_proto = ethertype;
6421}
6422
6423/**
6424 * skb_mpls_push() - push a new MPLS header after mac_len bytes from start of
6425 * the packet
6426 *
6427 * @skb: buffer
6428 * @mpls_lse: MPLS label stack entry to push
6429 * @mpls_proto: ethertype of the new MPLS header (expects 0x8847 or 0x8848)
6430 * @mac_len: length of the MAC header
6431 * @ethernet: flag to indicate if the resulting packet after skb_mpls_push is
6432 * ethernet
6433 *
6434 * Expects skb->data at mac header.
6435 *
6436 * Returns 0 on success, -errno otherwise.
6437 */
6438int skb_mpls_push(struct sk_buff *skb, __be32 mpls_lse, __be16 mpls_proto,
6439 int mac_len, bool ethernet)
6440{
6441 struct mpls_shim_hdr *lse;
6442 int err;
6443
6444 if (unlikely(!eth_p_mpls(mpls_proto)))
6445 return -EINVAL;
6446
6447 /* Networking stack does not allow simultaneous Tunnel and MPLS GSO. */
6448 if (skb->encapsulation)
6449 return -EINVAL;
6450
6451 err = skb_cow_head(skb, MPLS_HLEN);
6452 if (unlikely(err))
6453 return err;
6454
6455 if (!skb->inner_protocol) {
6456 skb_set_inner_network_header(skb, skb_network_offset(skb));
6457 skb_set_inner_protocol(skb, skb->protocol);
6458 }
6459
6460 skb_push(skb, MPLS_HLEN);
6461 memmove(skb_mac_header(skb) - MPLS_HLEN, skb_mac_header(skb),
6462 mac_len);
6463 skb_reset_mac_header(skb);
6464 skb_set_network_header(skb, mac_len);
6465 skb_reset_mac_len(skb);
6466
6467 lse = mpls_hdr(skb);
6468 lse->label_stack_entry = mpls_lse;
6469 skb_postpush_rcsum(skb, lse, MPLS_HLEN);
6470
6471 if (ethernet && mac_len >= ETH_HLEN)
6472 skb_mod_eth_type(skb, eth_hdr(skb), mpls_proto);
6473 skb->protocol = mpls_proto;
6474
6475 return 0;
6476}
6477EXPORT_SYMBOL_GPL(skb_mpls_push);
6478
6479/**
6480 * skb_mpls_pop() - pop the outermost MPLS header
6481 *
6482 * @skb: buffer
6483 * @next_proto: ethertype of header after popped MPLS header
6484 * @mac_len: length of the MAC header
6485 * @ethernet: flag to indicate if the packet is ethernet
6486 *
6487 * Expects skb->data at mac header.
6488 *
6489 * Returns 0 on success, -errno otherwise.
6490 */
6491int skb_mpls_pop(struct sk_buff *skb, __be16 next_proto, int mac_len,
6492 bool ethernet)
6493{
6494 int err;
6495
6496 if (unlikely(!eth_p_mpls(skb->protocol)))
6497 return 0;
6498
6499 err = skb_ensure_writable(skb, mac_len + MPLS_HLEN);
6500 if (unlikely(err))
6501 return err;
6502
6503 skb_postpull_rcsum(skb, mpls_hdr(skb), MPLS_HLEN);
6504 memmove(skb_mac_header(skb) + MPLS_HLEN, skb_mac_header(skb),
6505 mac_len);
6506
6507 __skb_pull(skb, MPLS_HLEN);
6508 skb_reset_mac_header(skb);
6509 skb_set_network_header(skb, mac_len);
6510
6511 if (ethernet && mac_len >= ETH_HLEN) {
6512 struct ethhdr *hdr;
6513
6514 /* use mpls_hdr() to get ethertype to account for VLANs. */
6515 hdr = (struct ethhdr *)((void *)mpls_hdr(skb) - ETH_HLEN);
6516 skb_mod_eth_type(skb, hdr, next_proto);
6517 }
6518 skb->protocol = next_proto;
6519
6520 return 0;
6521}
6522EXPORT_SYMBOL_GPL(skb_mpls_pop);
6523
6524/**
6525 * skb_mpls_update_lse() - modify outermost MPLS header and update csum
6526 *
6527 * @skb: buffer
6528 * @mpls_lse: new MPLS label stack entry to update to
6529 *
6530 * Expects skb->data at mac header.
6531 *
6532 * Returns 0 on success, -errno otherwise.
6533 */
6534int skb_mpls_update_lse(struct sk_buff *skb, __be32 mpls_lse)
6535{
6536 int err;
6537
6538 if (unlikely(!eth_p_mpls(skb->protocol)))
6539 return -EINVAL;
6540
6541 err = skb_ensure_writable(skb, skb->mac_len + MPLS_HLEN);
6542 if (unlikely(err))
6543 return err;
6544
6545 if (skb->ip_summed == CHECKSUM_COMPLETE) {
6546 __be32 diff[] = { ~mpls_hdr(skb)->label_stack_entry, mpls_lse };
6547
6548 skb->csum = csum_partial((char *)diff, sizeof(diff), skb->csum);
6549 }
6550
6551 mpls_hdr(skb)->label_stack_entry = mpls_lse;
6552
6553 return 0;
6554}
6555EXPORT_SYMBOL_GPL(skb_mpls_update_lse);
6556
6557/**
6558 * skb_mpls_dec_ttl() - decrement the TTL of the outermost MPLS header
6559 *
6560 * @skb: buffer
6561 *
6562 * Expects skb->data at mac header.
6563 *
6564 * Returns 0 on success, -errno otherwise.
6565 */
6566int skb_mpls_dec_ttl(struct sk_buff *skb)
6567{
6568 u32 lse;
6569 u8 ttl;
6570
6571 if (unlikely(!eth_p_mpls(skb->protocol)))
6572 return -EINVAL;
6573
6574 if (!pskb_may_pull(skb, skb_network_offset(skb) + MPLS_HLEN))
6575 return -ENOMEM;
6576
6577 lse = be32_to_cpu(mpls_hdr(skb)->label_stack_entry);
6578 ttl = (lse & MPLS_LS_TTL_MASK) >> MPLS_LS_TTL_SHIFT;
6579 if (!--ttl)
6580 return -EINVAL;
6581
6582 lse &= ~MPLS_LS_TTL_MASK;
6583 lse |= ttl << MPLS_LS_TTL_SHIFT;
6584
6585 return skb_mpls_update_lse(skb, cpu_to_be32(lse));
6586}
6587EXPORT_SYMBOL_GPL(skb_mpls_dec_ttl);
6588
6589/**
6590 * alloc_skb_with_frags - allocate skb with page frags
6591 *
6592 * @header_len: size of linear part
6593 * @data_len: needed length in frags
6594 * @order: max page order desired.
6595 * @errcode: pointer to error code if any
6596 * @gfp_mask: allocation mask
6597 *
6598 * This can be used to allocate a paged skb, given a maximal order for frags.
6599 */
6600struct sk_buff *alloc_skb_with_frags(unsigned long header_len,
6601 unsigned long data_len,
6602 int order,
6603 int *errcode,
6604 gfp_t gfp_mask)
6605{
6606 unsigned long chunk;
6607 struct sk_buff *skb;
6608 struct page *page;
6609 int nr_frags = 0;
6610
6611 *errcode = -EMSGSIZE;
6612 if (unlikely(data_len > MAX_SKB_FRAGS * (PAGE_SIZE << order)))
6613 return NULL;
6614
6615 *errcode = -ENOBUFS;
6616 skb = alloc_skb(header_len, gfp_mask);
6617 if (!skb)
6618 return NULL;
6619
6620 while (data_len) {
6621 if (nr_frags == MAX_SKB_FRAGS - 1)
6622 goto failure;
6623 while (order && PAGE_ALIGN(data_len) < (PAGE_SIZE << order))
6624 order--;
6625
6626 if (order) {
6627 page = alloc_pages((gfp_mask & ~__GFP_DIRECT_RECLAIM) |
6628 __GFP_COMP |
6629 __GFP_NOWARN,
6630 order);
6631 if (!page) {
6632 order--;
6633 continue;
6634 }
6635 } else {
6636 page = alloc_page(gfp_mask);
6637 if (!page)
6638 goto failure;
6639 }
6640 chunk = min_t(unsigned long, data_len,
6641 PAGE_SIZE << order);
6642 skb_fill_page_desc(skb, nr_frags, page, 0, chunk);
6643 nr_frags++;
6644 skb->truesize += (PAGE_SIZE << order);
6645 data_len -= chunk;
6646 }
6647 return skb;
6648
6649failure:
6650 kfree_skb(skb);
6651 return NULL;
6652}
6653EXPORT_SYMBOL(alloc_skb_with_frags);
6654
6655/* carve out the first off bytes from skb when off < headlen */
6656static int pskb_carve_inside_header(struct sk_buff *skb, const u32 off,
6657 const int headlen, gfp_t gfp_mask)
6658{
6659 int i;
6660 unsigned int size = skb_end_offset(skb);
6661 int new_hlen = headlen - off;
6662 u8 *data;
6663
6664 if (skb_pfmemalloc(skb))
6665 gfp_mask |= __GFP_MEMALLOC;
6666
6667 data = kmalloc_reserve(&size, gfp_mask, NUMA_NO_NODE, NULL);
6668 if (!data)
6669 return -ENOMEM;
6670 size = SKB_WITH_OVERHEAD(size);
6671
6672 /* Copy real data, and all frags */
6673 skb_copy_from_linear_data_offset(skb, off, data, new_hlen);
6674 skb->len -= off;
6675
6676 memcpy((struct skb_shared_info *)(data + size),
6677 skb_shinfo(skb),
6678 offsetof(struct skb_shared_info,
6679 frags[skb_shinfo(skb)->nr_frags]));
6680 if (skb_cloned(skb)) {
6681 /* drop the old head gracefully */
6682 if (skb_orphan_frags(skb, gfp_mask)) {
6683 skb_kfree_head(data, size);
6684 return -ENOMEM;
6685 }
6686 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
6687 skb_frag_ref(skb, i);
6688 if (skb_has_frag_list(skb))
6689 skb_clone_fraglist(skb);
6690 skb_release_data(skb, SKB_CONSUMED);
6691 } else {
6692 /* we can reuse existing recount- all we did was
6693 * relocate values
6694 */
6695 skb_free_head(skb);
6696 }
6697
6698 skb->head = data;
6699 skb->data = data;
6700 skb->head_frag = 0;
6701 skb_set_end_offset(skb, size);
6702 skb_set_tail_pointer(skb, skb_headlen(skb));
6703 skb_headers_offset_update(skb, 0);
6704 skb->cloned = 0;
6705 skb->hdr_len = 0;
6706 skb->nohdr = 0;
6707 atomic_set(&skb_shinfo(skb)->dataref, 1);
6708
6709 return 0;
6710}
6711
6712static int pskb_carve(struct sk_buff *skb, const u32 off, gfp_t gfp);
6713
6714/* carve out the first eat bytes from skb's frag_list. May recurse into
6715 * pskb_carve()
6716 */
6717static int pskb_carve_frag_list(struct sk_buff *skb,
6718 struct skb_shared_info *shinfo, int eat,
6719 gfp_t gfp_mask)
6720{
6721 struct sk_buff *list = shinfo->frag_list;
6722 struct sk_buff *clone = NULL;
6723 struct sk_buff *insp = NULL;
6724
6725 do {
6726 if (!list) {
6727 pr_err("Not enough bytes to eat. Want %d\n", eat);
6728 return -EFAULT;
6729 }
6730 if (list->len <= eat) {
6731 /* Eaten as whole. */
6732 eat -= list->len;
6733 list = list->next;
6734 insp = list;
6735 } else {
6736 /* Eaten partially. */
6737 if (skb_shared(list)) {
6738 clone = skb_clone(list, gfp_mask);
6739 if (!clone)
6740 return -ENOMEM;
6741 insp = list->next;
6742 list = clone;
6743 } else {
6744 /* This may be pulled without problems. */
6745 insp = list;
6746 }
6747 if (pskb_carve(list, eat, gfp_mask) < 0) {
6748 kfree_skb(clone);
6749 return -ENOMEM;
6750 }
6751 break;
6752 }
6753 } while (eat);
6754
6755 /* Free pulled out fragments. */
6756 while ((list = shinfo->frag_list) != insp) {
6757 shinfo->frag_list = list->next;
6758 consume_skb(list);
6759 }
6760 /* And insert new clone at head. */
6761 if (clone) {
6762 clone->next = list;
6763 shinfo->frag_list = clone;
6764 }
6765 return 0;
6766}
6767
6768/* carve off first len bytes from skb. Split line (off) is in the
6769 * non-linear part of skb
6770 */
6771static int pskb_carve_inside_nonlinear(struct sk_buff *skb, const u32 off,
6772 int pos, gfp_t gfp_mask)
6773{
6774 int i, k = 0;
6775 unsigned int size = skb_end_offset(skb);
6776 u8 *data;
6777 const int nfrags = skb_shinfo(skb)->nr_frags;
6778 struct skb_shared_info *shinfo;
6779
6780 if (skb_pfmemalloc(skb))
6781 gfp_mask |= __GFP_MEMALLOC;
6782
6783 data = kmalloc_reserve(&size, gfp_mask, NUMA_NO_NODE, NULL);
6784 if (!data)
6785 return -ENOMEM;
6786 size = SKB_WITH_OVERHEAD(size);
6787
6788 memcpy((struct skb_shared_info *)(data + size),
6789 skb_shinfo(skb), offsetof(struct skb_shared_info, frags[0]));
6790 if (skb_orphan_frags(skb, gfp_mask)) {
6791 skb_kfree_head(data, size);
6792 return -ENOMEM;
6793 }
6794 shinfo = (struct skb_shared_info *)(data + size);
6795 for (i = 0; i < nfrags; i++) {
6796 int fsize = skb_frag_size(&skb_shinfo(skb)->frags[i]);
6797
6798 if (pos + fsize > off) {
6799 shinfo->frags[k] = skb_shinfo(skb)->frags[i];
6800
6801 if (pos < off) {
6802 /* Split frag.
6803 * We have two variants in this case:
6804 * 1. Move all the frag to the second
6805 * part, if it is possible. F.e.
6806 * this approach is mandatory for TUX,
6807 * where splitting is expensive.
6808 * 2. Split is accurately. We make this.
6809 */
6810 skb_frag_off_add(&shinfo->frags[0], off - pos);
6811 skb_frag_size_sub(&shinfo->frags[0], off - pos);
6812 }
6813 skb_frag_ref(skb, i);
6814 k++;
6815 }
6816 pos += fsize;
6817 }
6818 shinfo->nr_frags = k;
6819 if (skb_has_frag_list(skb))
6820 skb_clone_fraglist(skb);
6821
6822 /* split line is in frag list */
6823 if (k == 0 && pskb_carve_frag_list(skb, shinfo, off - pos, gfp_mask)) {
6824 /* skb_frag_unref() is not needed here as shinfo->nr_frags = 0. */
6825 if (skb_has_frag_list(skb))
6826 kfree_skb_list(skb_shinfo(skb)->frag_list);
6827 skb_kfree_head(data, size);
6828 return -ENOMEM;
6829 }
6830 skb_release_data(skb, SKB_CONSUMED);
6831
6832 skb->head = data;
6833 skb->head_frag = 0;
6834 skb->data = data;
6835 skb_set_end_offset(skb, size);
6836 skb_reset_tail_pointer(skb);
6837 skb_headers_offset_update(skb, 0);
6838 skb->cloned = 0;
6839 skb->hdr_len = 0;
6840 skb->nohdr = 0;
6841 skb->len -= off;
6842 skb->data_len = skb->len;
6843 atomic_set(&skb_shinfo(skb)->dataref, 1);
6844 return 0;
6845}
6846
6847/* remove len bytes from the beginning of the skb */
6848static int pskb_carve(struct sk_buff *skb, const u32 len, gfp_t gfp)
6849{
6850 int headlen = skb_headlen(skb);
6851
6852 if (len < headlen)
6853 return pskb_carve_inside_header(skb, len, headlen, gfp);
6854 else
6855 return pskb_carve_inside_nonlinear(skb, len, headlen, gfp);
6856}
6857
6858/* Extract to_copy bytes starting at off from skb, and return this in
6859 * a new skb
6860 */
6861struct sk_buff *pskb_extract(struct sk_buff *skb, int off,
6862 int to_copy, gfp_t gfp)
6863{
6864 struct sk_buff *clone = skb_clone(skb, gfp);
6865
6866 if (!clone)
6867 return NULL;
6868
6869 if (pskb_carve(clone, off, gfp) < 0 ||
6870 pskb_trim(clone, to_copy)) {
6871 kfree_skb(clone);
6872 return NULL;
6873 }
6874 return clone;
6875}
6876EXPORT_SYMBOL(pskb_extract);
6877
6878/**
6879 * skb_condense - try to get rid of fragments/frag_list if possible
6880 * @skb: buffer
6881 *
6882 * Can be used to save memory before skb is added to a busy queue.
6883 * If packet has bytes in frags and enough tail room in skb->head,
6884 * pull all of them, so that we can free the frags right now and adjust
6885 * truesize.
6886 * Notes:
6887 * We do not reallocate skb->head thus can not fail.
6888 * Caller must re-evaluate skb->truesize if needed.
6889 */
6890void skb_condense(struct sk_buff *skb)
6891{
6892 if (skb->data_len) {
6893 if (skb->data_len > skb->end - skb->tail ||
6894 skb_cloned(skb) || !skb_frags_readable(skb))
6895 return;
6896
6897 /* Nice, we can free page frag(s) right now */
6898 __pskb_pull_tail(skb, skb->data_len);
6899 }
6900 /* At this point, skb->truesize might be over estimated,
6901 * because skb had a fragment, and fragments do not tell
6902 * their truesize.
6903 * When we pulled its content into skb->head, fragment
6904 * was freed, but __pskb_pull_tail() could not possibly
6905 * adjust skb->truesize, not knowing the frag truesize.
6906 */
6907 skb->truesize = SKB_TRUESIZE(skb_end_offset(skb));
6908}
6909EXPORT_SYMBOL(skb_condense);
6910
6911#ifdef CONFIG_SKB_EXTENSIONS
6912static void *skb_ext_get_ptr(struct skb_ext *ext, enum skb_ext_id id)
6913{
6914 return (void *)ext + (ext->offset[id] * SKB_EXT_ALIGN_VALUE);
6915}
6916
6917/**
6918 * __skb_ext_alloc - allocate a new skb extensions storage
6919 *
6920 * @flags: See kmalloc().
6921 *
6922 * Returns the newly allocated pointer. The pointer can later attached to a
6923 * skb via __skb_ext_set().
6924 * Note: caller must handle the skb_ext as an opaque data.
6925 */
6926struct skb_ext *__skb_ext_alloc(gfp_t flags)
6927{
6928 struct skb_ext *new = kmem_cache_alloc(skbuff_ext_cache, flags);
6929
6930 if (new) {
6931 memset(new->offset, 0, sizeof(new->offset));
6932 refcount_set(&new->refcnt, 1);
6933 }
6934
6935 return new;
6936}
6937
6938static struct skb_ext *skb_ext_maybe_cow(struct skb_ext *old,
6939 unsigned int old_active)
6940{
6941 struct skb_ext *new;
6942
6943 if (refcount_read(&old->refcnt) == 1)
6944 return old;
6945
6946 new = kmem_cache_alloc(skbuff_ext_cache, GFP_ATOMIC);
6947 if (!new)
6948 return NULL;
6949
6950 memcpy(new, old, old->chunks * SKB_EXT_ALIGN_VALUE);
6951 refcount_set(&new->refcnt, 1);
6952
6953#ifdef CONFIG_XFRM
6954 if (old_active & (1 << SKB_EXT_SEC_PATH)) {
6955 struct sec_path *sp = skb_ext_get_ptr(old, SKB_EXT_SEC_PATH);
6956 unsigned int i;
6957
6958 for (i = 0; i < sp->len; i++)
6959 xfrm_state_hold(sp->xvec[i]);
6960 }
6961#endif
6962#ifdef CONFIG_MCTP_FLOWS
6963 if (old_active & (1 << SKB_EXT_MCTP)) {
6964 struct mctp_flow *flow = skb_ext_get_ptr(old, SKB_EXT_MCTP);
6965
6966 if (flow->key)
6967 refcount_inc(&flow->key->refs);
6968 }
6969#endif
6970 __skb_ext_put(old);
6971 return new;
6972}
6973
6974/**
6975 * __skb_ext_set - attach the specified extension storage to this skb
6976 * @skb: buffer
6977 * @id: extension id
6978 * @ext: extension storage previously allocated via __skb_ext_alloc()
6979 *
6980 * Existing extensions, if any, are cleared.
6981 *
6982 * Returns the pointer to the extension.
6983 */
6984void *__skb_ext_set(struct sk_buff *skb, enum skb_ext_id id,
6985 struct skb_ext *ext)
6986{
6987 unsigned int newlen, newoff = SKB_EXT_CHUNKSIZEOF(*ext);
6988
6989 skb_ext_put(skb);
6990 newlen = newoff + skb_ext_type_len[id];
6991 ext->chunks = newlen;
6992 ext->offset[id] = newoff;
6993 skb->extensions = ext;
6994 skb->active_extensions = 1 << id;
6995 return skb_ext_get_ptr(ext, id);
6996}
6997
6998/**
6999 * skb_ext_add - allocate space for given extension, COW if needed
7000 * @skb: buffer
7001 * @id: extension to allocate space for
7002 *
7003 * Allocates enough space for the given extension.
7004 * If the extension is already present, a pointer to that extension
7005 * is returned.
7006 *
7007 * If the skb was cloned, COW applies and the returned memory can be
7008 * modified without changing the extension space of clones buffers.
7009 *
7010 * Returns pointer to the extension or NULL on allocation failure.
7011 */
7012void *skb_ext_add(struct sk_buff *skb, enum skb_ext_id id)
7013{
7014 struct skb_ext *new, *old = NULL;
7015 unsigned int newlen, newoff;
7016
7017 if (skb->active_extensions) {
7018 old = skb->extensions;
7019
7020 new = skb_ext_maybe_cow(old, skb->active_extensions);
7021 if (!new)
7022 return NULL;
7023
7024 if (__skb_ext_exist(new, id))
7025 goto set_active;
7026
7027 newoff = new->chunks;
7028 } else {
7029 newoff = SKB_EXT_CHUNKSIZEOF(*new);
7030
7031 new = __skb_ext_alloc(GFP_ATOMIC);
7032 if (!new)
7033 return NULL;
7034 }
7035
7036 newlen = newoff + skb_ext_type_len[id];
7037 new->chunks = newlen;
7038 new->offset[id] = newoff;
7039set_active:
7040 skb->slow_gro = 1;
7041 skb->extensions = new;
7042 skb->active_extensions |= 1 << id;
7043 return skb_ext_get_ptr(new, id);
7044}
7045EXPORT_SYMBOL(skb_ext_add);
7046
7047#ifdef CONFIG_XFRM
7048static void skb_ext_put_sp(struct sec_path *sp)
7049{
7050 unsigned int i;
7051
7052 for (i = 0; i < sp->len; i++)
7053 xfrm_state_put(sp->xvec[i]);
7054}
7055#endif
7056
7057#ifdef CONFIG_MCTP_FLOWS
7058static void skb_ext_put_mctp(struct mctp_flow *flow)
7059{
7060 if (flow->key)
7061 mctp_key_unref(flow->key);
7062}
7063#endif
7064
7065void __skb_ext_del(struct sk_buff *skb, enum skb_ext_id id)
7066{
7067 struct skb_ext *ext = skb->extensions;
7068
7069 skb->active_extensions &= ~(1 << id);
7070 if (skb->active_extensions == 0) {
7071 skb->extensions = NULL;
7072 __skb_ext_put(ext);
7073#ifdef CONFIG_XFRM
7074 } else if (id == SKB_EXT_SEC_PATH &&
7075 refcount_read(&ext->refcnt) == 1) {
7076 struct sec_path *sp = skb_ext_get_ptr(ext, SKB_EXT_SEC_PATH);
7077
7078 skb_ext_put_sp(sp);
7079 sp->len = 0;
7080#endif
7081 }
7082}
7083EXPORT_SYMBOL(__skb_ext_del);
7084
7085void __skb_ext_put(struct skb_ext *ext)
7086{
7087 /* If this is last clone, nothing can increment
7088 * it after check passes. Avoids one atomic op.
7089 */
7090 if (refcount_read(&ext->refcnt) == 1)
7091 goto free_now;
7092
7093 if (!refcount_dec_and_test(&ext->refcnt))
7094 return;
7095free_now:
7096#ifdef CONFIG_XFRM
7097 if (__skb_ext_exist(ext, SKB_EXT_SEC_PATH))
7098 skb_ext_put_sp(skb_ext_get_ptr(ext, SKB_EXT_SEC_PATH));
7099#endif
7100#ifdef CONFIG_MCTP_FLOWS
7101 if (__skb_ext_exist(ext, SKB_EXT_MCTP))
7102 skb_ext_put_mctp(skb_ext_get_ptr(ext, SKB_EXT_MCTP));
7103#endif
7104
7105 kmem_cache_free(skbuff_ext_cache, ext);
7106}
7107EXPORT_SYMBOL(__skb_ext_put);
7108#endif /* CONFIG_SKB_EXTENSIONS */
7109
7110static void kfree_skb_napi_cache(struct sk_buff *skb)
7111{
7112 /* if SKB is a clone, don't handle this case */
7113 if (skb->fclone != SKB_FCLONE_UNAVAILABLE) {
7114 __kfree_skb(skb);
7115 return;
7116 }
7117
7118 local_bh_disable();
7119 __napi_kfree_skb(skb, SKB_CONSUMED);
7120 local_bh_enable();
7121}
7122
7123/**
7124 * skb_attempt_defer_free - queue skb for remote freeing
7125 * @skb: buffer
7126 *
7127 * Put @skb in a per-cpu list, using the cpu which
7128 * allocated the skb/pages to reduce false sharing
7129 * and memory zone spinlock contention.
7130 */
7131void skb_attempt_defer_free(struct sk_buff *skb)
7132{
7133 int cpu = skb->alloc_cpu;
7134 struct softnet_data *sd;
7135 unsigned int defer_max;
7136 bool kick;
7137
7138 if (cpu == raw_smp_processor_id() ||
7139 WARN_ON_ONCE(cpu >= nr_cpu_ids) ||
7140 !cpu_online(cpu)) {
7141nodefer: kfree_skb_napi_cache(skb);
7142 return;
7143 }
7144
7145 DEBUG_NET_WARN_ON_ONCE(skb_dst(skb));
7146 DEBUG_NET_WARN_ON_ONCE(skb->destructor);
7147
7148 sd = &per_cpu(softnet_data, cpu);
7149 defer_max = READ_ONCE(net_hotdata.sysctl_skb_defer_max);
7150 if (READ_ONCE(sd->defer_count) >= defer_max)
7151 goto nodefer;
7152
7153 spin_lock_bh(&sd->defer_lock);
7154 /* Send an IPI every time queue reaches half capacity. */
7155 kick = sd->defer_count == (defer_max >> 1);
7156 /* Paired with the READ_ONCE() few lines above */
7157 WRITE_ONCE(sd->defer_count, sd->defer_count + 1);
7158
7159 skb->next = sd->defer_list;
7160 /* Paired with READ_ONCE() in skb_defer_free_flush() */
7161 WRITE_ONCE(sd->defer_list, skb);
7162 spin_unlock_bh(&sd->defer_lock);
7163
7164 /* Make sure to trigger NET_RX_SOFTIRQ on the remote CPU
7165 * if we are unlucky enough (this seems very unlikely).
7166 */
7167 if (unlikely(kick))
7168 kick_defer_list_purge(sd, cpu);
7169}
7170
7171static void skb_splice_csum_page(struct sk_buff *skb, struct page *page,
7172 size_t offset, size_t len)
7173{
7174 const char *kaddr;
7175 __wsum csum;
7176
7177 kaddr = kmap_local_page(page);
7178 csum = csum_partial(kaddr + offset, len, 0);
7179 kunmap_local(kaddr);
7180 skb->csum = csum_block_add(skb->csum, csum, skb->len);
7181}
7182
7183/**
7184 * skb_splice_from_iter - Splice (or copy) pages to skbuff
7185 * @skb: The buffer to add pages to
7186 * @iter: Iterator representing the pages to be added
7187 * @maxsize: Maximum amount of pages to be added
7188 * @gfp: Allocation flags
7189 *
7190 * This is a common helper function for supporting MSG_SPLICE_PAGES. It
7191 * extracts pages from an iterator and adds them to the socket buffer if
7192 * possible, copying them to fragments if not possible (such as if they're slab
7193 * pages).
7194 *
7195 * Returns the amount of data spliced/copied or -EMSGSIZE if there's
7196 * insufficient space in the buffer to transfer anything.
7197 */
7198ssize_t skb_splice_from_iter(struct sk_buff *skb, struct iov_iter *iter,
7199 ssize_t maxsize, gfp_t gfp)
7200{
7201 size_t frag_limit = READ_ONCE(net_hotdata.sysctl_max_skb_frags);
7202 struct page *pages[8], **ppages = pages;
7203 ssize_t spliced = 0, ret = 0;
7204 unsigned int i;
7205
7206 while (iter->count > 0) {
7207 ssize_t space, nr, len;
7208 size_t off;
7209
7210 ret = -EMSGSIZE;
7211 space = frag_limit - skb_shinfo(skb)->nr_frags;
7212 if (space < 0)
7213 break;
7214
7215 /* We might be able to coalesce without increasing nr_frags */
7216 nr = clamp_t(size_t, space, 1, ARRAY_SIZE(pages));
7217
7218 len = iov_iter_extract_pages(iter, &ppages, maxsize, nr, 0, &off);
7219 if (len <= 0) {
7220 ret = len ?: -EIO;
7221 break;
7222 }
7223
7224 i = 0;
7225 do {
7226 struct page *page = pages[i++];
7227 size_t part = min_t(size_t, PAGE_SIZE - off, len);
7228
7229 ret = -EIO;
7230 if (WARN_ON_ONCE(!sendpage_ok(page)))
7231 goto out;
7232
7233 ret = skb_append_pagefrags(skb, page, off, part,
7234 frag_limit);
7235 if (ret < 0) {
7236 iov_iter_revert(iter, len);
7237 goto out;
7238 }
7239
7240 if (skb->ip_summed == CHECKSUM_NONE)
7241 skb_splice_csum_page(skb, page, off, part);
7242
7243 off = 0;
7244 spliced += part;
7245 maxsize -= part;
7246 len -= part;
7247 } while (len > 0);
7248
7249 if (maxsize <= 0)
7250 break;
7251 }
7252
7253out:
7254 skb_len_add(skb, spliced);
7255 return spliced ?: ret;
7256}
7257EXPORT_SYMBOL(skb_splice_from_iter);
7258
7259static __always_inline
7260size_t memcpy_from_iter_csum(void *iter_from, size_t progress,
7261 size_t len, void *to, void *priv2)
7262{
7263 __wsum *csum = priv2;
7264 __wsum next = csum_partial_copy_nocheck(iter_from, to + progress, len);
7265
7266 *csum = csum_block_add(*csum, next, progress);
7267 return 0;
7268}
7269
7270static __always_inline
7271size_t copy_from_user_iter_csum(void __user *iter_from, size_t progress,
7272 size_t len, void *to, void *priv2)
7273{
7274 __wsum next, *csum = priv2;
7275
7276 next = csum_and_copy_from_user(iter_from, to + progress, len);
7277 *csum = csum_block_add(*csum, next, progress);
7278 return next ? 0 : len;
7279}
7280
7281bool csum_and_copy_from_iter_full(void *addr, size_t bytes,
7282 __wsum *csum, struct iov_iter *i)
7283{
7284 size_t copied;
7285
7286 if (WARN_ON_ONCE(!i->data_source))
7287 return false;
7288 copied = iterate_and_advance2(i, bytes, addr, csum,
7289 copy_from_user_iter_csum,
7290 memcpy_from_iter_csum);
7291 if (likely(copied == bytes))
7292 return true;
7293 iov_iter_revert(i, copied);
7294 return false;
7295}
7296EXPORT_SYMBOL(csum_and_copy_from_iter_full);