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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/splice.h>
55#include <linux/cache.h>
56#include <linux/rtnetlink.h>
57#include <linux/init.h>
58#include <linux/scatterlist.h>
59#include <linux/errqueue.h>
60#include <linux/prefetch.h>
61#include <linux/if_vlan.h>
62#include <linux/mpls.h>
63#include <linux/kcov.h>
64
65#include <net/protocol.h>
66#include <net/dst.h>
67#include <net/sock.h>
68#include <net/checksum.h>
69#include <net/ip6_checksum.h>
70#include <net/xfrm.h>
71#include <net/mpls.h>
72#include <net/mptcp.h>
73#include <net/page_pool.h>
74
75#include <linux/uaccess.h>
76#include <trace/events/skb.h>
77#include <linux/highmem.h>
78#include <linux/capability.h>
79#include <linux/user_namespace.h>
80#include <linux/indirect_call_wrapper.h>
81
82#include "datagram.h"
83
84struct kmem_cache *skbuff_head_cache __ro_after_init;
85static struct kmem_cache *skbuff_fclone_cache __ro_after_init;
86#ifdef CONFIG_SKB_EXTENSIONS
87static struct kmem_cache *skbuff_ext_cache __ro_after_init;
88#endif
89int sysctl_max_skb_frags __read_mostly = MAX_SKB_FRAGS;
90EXPORT_SYMBOL(sysctl_max_skb_frags);
91
92/**
93 * skb_panic - private function for out-of-line support
94 * @skb: buffer
95 * @sz: size
96 * @addr: address
97 * @msg: skb_over_panic or skb_under_panic
98 *
99 * Out-of-line support for skb_put() and skb_push().
100 * Called via the wrapper skb_over_panic() or skb_under_panic().
101 * Keep out of line to prevent kernel bloat.
102 * __builtin_return_address is not used because it is not always reliable.
103 */
104static void skb_panic(struct sk_buff *skb, unsigned int sz, void *addr,
105 const char msg[])
106{
107 pr_emerg("%s: text:%px len:%d put:%d head:%px data:%px tail:%#lx end:%#lx dev:%s\n",
108 msg, addr, skb->len, sz, skb->head, skb->data,
109 (unsigned long)skb->tail, (unsigned long)skb->end,
110 skb->dev ? skb->dev->name : "<NULL>");
111 BUG();
112}
113
114static void skb_over_panic(struct sk_buff *skb, unsigned int sz, void *addr)
115{
116 skb_panic(skb, sz, addr, __func__);
117}
118
119static void skb_under_panic(struct sk_buff *skb, unsigned int sz, void *addr)
120{
121 skb_panic(skb, sz, addr, __func__);
122}
123
124#define NAPI_SKB_CACHE_SIZE 64
125#define NAPI_SKB_CACHE_BULK 16
126#define NAPI_SKB_CACHE_HALF (NAPI_SKB_CACHE_SIZE / 2)
127
128struct napi_alloc_cache {
129 struct page_frag_cache page;
130 unsigned int skb_count;
131 void *skb_cache[NAPI_SKB_CACHE_SIZE];
132};
133
134static DEFINE_PER_CPU(struct page_frag_cache, netdev_alloc_cache);
135static DEFINE_PER_CPU(struct napi_alloc_cache, napi_alloc_cache);
136
137static void *__alloc_frag_align(unsigned int fragsz, gfp_t gfp_mask,
138 unsigned int align_mask)
139{
140 struct napi_alloc_cache *nc = this_cpu_ptr(&napi_alloc_cache);
141
142 return page_frag_alloc_align(&nc->page, fragsz, gfp_mask, align_mask);
143}
144
145void *__napi_alloc_frag_align(unsigned int fragsz, unsigned int align_mask)
146{
147 fragsz = SKB_DATA_ALIGN(fragsz);
148
149 return __alloc_frag_align(fragsz, GFP_ATOMIC, align_mask);
150}
151EXPORT_SYMBOL(__napi_alloc_frag_align);
152
153void *__netdev_alloc_frag_align(unsigned int fragsz, unsigned int align_mask)
154{
155 struct page_frag_cache *nc;
156 void *data;
157
158 fragsz = SKB_DATA_ALIGN(fragsz);
159 if (in_irq() || irqs_disabled()) {
160 nc = this_cpu_ptr(&netdev_alloc_cache);
161 data = page_frag_alloc_align(nc, fragsz, GFP_ATOMIC, align_mask);
162 } else {
163 local_bh_disable();
164 data = __alloc_frag_align(fragsz, GFP_ATOMIC, align_mask);
165 local_bh_enable();
166 }
167 return data;
168}
169EXPORT_SYMBOL(__netdev_alloc_frag_align);
170
171static struct sk_buff *napi_skb_cache_get(void)
172{
173 struct napi_alloc_cache *nc = this_cpu_ptr(&napi_alloc_cache);
174 struct sk_buff *skb;
175
176 if (unlikely(!nc->skb_count))
177 nc->skb_count = kmem_cache_alloc_bulk(skbuff_head_cache,
178 GFP_ATOMIC,
179 NAPI_SKB_CACHE_BULK,
180 nc->skb_cache);
181 if (unlikely(!nc->skb_count))
182 return NULL;
183
184 skb = nc->skb_cache[--nc->skb_count];
185 kasan_unpoison_object_data(skbuff_head_cache, skb);
186
187 return skb;
188}
189
190/* Caller must provide SKB that is memset cleared */
191static void __build_skb_around(struct sk_buff *skb, void *data,
192 unsigned int frag_size)
193{
194 struct skb_shared_info *shinfo;
195 unsigned int size = frag_size ? : ksize(data);
196
197 size -= SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
198
199 /* Assumes caller memset cleared SKB */
200 skb->truesize = SKB_TRUESIZE(size);
201 refcount_set(&skb->users, 1);
202 skb->head = data;
203 skb->data = data;
204 skb_reset_tail_pointer(skb);
205 skb->end = skb->tail + size;
206 skb->mac_header = (typeof(skb->mac_header))~0U;
207 skb->transport_header = (typeof(skb->transport_header))~0U;
208
209 /* make sure we initialize shinfo sequentially */
210 shinfo = skb_shinfo(skb);
211 memset(shinfo, 0, offsetof(struct skb_shared_info, dataref));
212 atomic_set(&shinfo->dataref, 1);
213
214 skb_set_kcov_handle(skb, kcov_common_handle());
215}
216
217/**
218 * __build_skb - build a network buffer
219 * @data: data buffer provided by caller
220 * @frag_size: size of data, or 0 if head was kmalloced
221 *
222 * Allocate a new &sk_buff. Caller provides space holding head and
223 * skb_shared_info. @data must have been allocated by kmalloc() only if
224 * @frag_size is 0, otherwise data should come from the page allocator
225 * or vmalloc()
226 * The return is the new skb buffer.
227 * On a failure the return is %NULL, and @data is not freed.
228 * Notes :
229 * Before IO, driver allocates only data buffer where NIC put incoming frame
230 * Driver should add room at head (NET_SKB_PAD) and
231 * MUST add room at tail (SKB_DATA_ALIGN(skb_shared_info))
232 * After IO, driver calls build_skb(), to allocate sk_buff and populate it
233 * before giving packet to stack.
234 * RX rings only contains data buffers, not full skbs.
235 */
236struct sk_buff *__build_skb(void *data, unsigned int frag_size)
237{
238 struct sk_buff *skb;
239
240 skb = kmem_cache_alloc(skbuff_head_cache, GFP_ATOMIC);
241 if (unlikely(!skb))
242 return NULL;
243
244 memset(skb, 0, offsetof(struct sk_buff, tail));
245 __build_skb_around(skb, data, frag_size);
246
247 return skb;
248}
249
250/* build_skb() is wrapper over __build_skb(), that specifically
251 * takes care of skb->head and skb->pfmemalloc
252 * This means that if @frag_size is not zero, then @data must be backed
253 * by a page fragment, not kmalloc() or vmalloc()
254 */
255struct sk_buff *build_skb(void *data, unsigned int frag_size)
256{
257 struct sk_buff *skb = __build_skb(data, frag_size);
258
259 if (skb && frag_size) {
260 skb->head_frag = 1;
261 if (page_is_pfmemalloc(virt_to_head_page(data)))
262 skb->pfmemalloc = 1;
263 }
264 return skb;
265}
266EXPORT_SYMBOL(build_skb);
267
268/**
269 * build_skb_around - build a network buffer around provided skb
270 * @skb: sk_buff provide by caller, must be memset cleared
271 * @data: data buffer provided by caller
272 * @frag_size: size of data, or 0 if head was kmalloced
273 */
274struct sk_buff *build_skb_around(struct sk_buff *skb,
275 void *data, unsigned int frag_size)
276{
277 if (unlikely(!skb))
278 return NULL;
279
280 __build_skb_around(skb, data, frag_size);
281
282 if (frag_size) {
283 skb->head_frag = 1;
284 if (page_is_pfmemalloc(virt_to_head_page(data)))
285 skb->pfmemalloc = 1;
286 }
287 return skb;
288}
289EXPORT_SYMBOL(build_skb_around);
290
291/**
292 * __napi_build_skb - build a network buffer
293 * @data: data buffer provided by caller
294 * @frag_size: size of data, or 0 if head was kmalloced
295 *
296 * Version of __build_skb() that uses NAPI percpu caches to obtain
297 * skbuff_head instead of inplace allocation.
298 *
299 * Returns a new &sk_buff on success, %NULL on allocation failure.
300 */
301static struct sk_buff *__napi_build_skb(void *data, unsigned int frag_size)
302{
303 struct sk_buff *skb;
304
305 skb = napi_skb_cache_get();
306 if (unlikely(!skb))
307 return NULL;
308
309 memset(skb, 0, offsetof(struct sk_buff, tail));
310 __build_skb_around(skb, data, frag_size);
311
312 return skb;
313}
314
315/**
316 * napi_build_skb - build a network buffer
317 * @data: data buffer provided by caller
318 * @frag_size: size of data, or 0 if head was kmalloced
319 *
320 * Version of __napi_build_skb() that takes care of skb->head_frag
321 * and skb->pfmemalloc when the data is a page or page fragment.
322 *
323 * Returns a new &sk_buff on success, %NULL on allocation failure.
324 */
325struct sk_buff *napi_build_skb(void *data, unsigned int frag_size)
326{
327 struct sk_buff *skb = __napi_build_skb(data, frag_size);
328
329 if (likely(skb) && frag_size) {
330 skb->head_frag = 1;
331 skb_propagate_pfmemalloc(virt_to_head_page(data), skb);
332 }
333
334 return skb;
335}
336EXPORT_SYMBOL(napi_build_skb);
337
338/*
339 * kmalloc_reserve is a wrapper around kmalloc_node_track_caller that tells
340 * the caller if emergency pfmemalloc reserves are being used. If it is and
341 * the socket is later found to be SOCK_MEMALLOC then PFMEMALLOC reserves
342 * may be used. Otherwise, the packet data may be discarded until enough
343 * memory is free
344 */
345static void *kmalloc_reserve(size_t size, gfp_t flags, int node,
346 bool *pfmemalloc)
347{
348 void *obj;
349 bool ret_pfmemalloc = false;
350
351 /*
352 * Try a regular allocation, when that fails and we're not entitled
353 * to the reserves, fail.
354 */
355 obj = kmalloc_node_track_caller(size,
356 flags | __GFP_NOMEMALLOC | __GFP_NOWARN,
357 node);
358 if (obj || !(gfp_pfmemalloc_allowed(flags)))
359 goto out;
360
361 /* Try again but now we are using pfmemalloc reserves */
362 ret_pfmemalloc = true;
363 obj = kmalloc_node_track_caller(size, flags, node);
364
365out:
366 if (pfmemalloc)
367 *pfmemalloc = ret_pfmemalloc;
368
369 return obj;
370}
371
372/* Allocate a new skbuff. We do this ourselves so we can fill in a few
373 * 'private' fields and also do memory statistics to find all the
374 * [BEEP] leaks.
375 *
376 */
377
378/**
379 * __alloc_skb - allocate a network buffer
380 * @size: size to allocate
381 * @gfp_mask: allocation mask
382 * @flags: If SKB_ALLOC_FCLONE is set, allocate from fclone cache
383 * instead of head cache and allocate a cloned (child) skb.
384 * If SKB_ALLOC_RX is set, __GFP_MEMALLOC will be used for
385 * allocations in case the data is required for writeback
386 * @node: numa node to allocate memory on
387 *
388 * Allocate a new &sk_buff. The returned buffer has no headroom and a
389 * tail room of at least size bytes. The object has a reference count
390 * of one. The return is the buffer. On a failure the return is %NULL.
391 *
392 * Buffers may only be allocated from interrupts using a @gfp_mask of
393 * %GFP_ATOMIC.
394 */
395struct sk_buff *__alloc_skb(unsigned int size, gfp_t gfp_mask,
396 int flags, int node)
397{
398 struct kmem_cache *cache;
399 struct sk_buff *skb;
400 u8 *data;
401 bool pfmemalloc;
402
403 cache = (flags & SKB_ALLOC_FCLONE)
404 ? skbuff_fclone_cache : skbuff_head_cache;
405
406 if (sk_memalloc_socks() && (flags & SKB_ALLOC_RX))
407 gfp_mask |= __GFP_MEMALLOC;
408
409 /* Get the HEAD */
410 if ((flags & (SKB_ALLOC_FCLONE | SKB_ALLOC_NAPI)) == SKB_ALLOC_NAPI &&
411 likely(node == NUMA_NO_NODE || node == numa_mem_id()))
412 skb = napi_skb_cache_get();
413 else
414 skb = kmem_cache_alloc_node(cache, gfp_mask & ~GFP_DMA, node);
415 if (unlikely(!skb))
416 return NULL;
417 prefetchw(skb);
418
419 /* We do our best to align skb_shared_info on a separate cache
420 * line. It usually works because kmalloc(X > SMP_CACHE_BYTES) gives
421 * aligned memory blocks, unless SLUB/SLAB debug is enabled.
422 * Both skb->head and skb_shared_info are cache line aligned.
423 */
424 size = SKB_DATA_ALIGN(size);
425 size += SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
426 data = kmalloc_reserve(size, gfp_mask, node, &pfmemalloc);
427 if (unlikely(!data))
428 goto nodata;
429 /* kmalloc(size) might give us more room than requested.
430 * Put skb_shared_info exactly at the end of allocated zone,
431 * to allow max possible filling before reallocation.
432 */
433 size = SKB_WITH_OVERHEAD(ksize(data));
434 prefetchw(data + size);
435
436 /*
437 * Only clear those fields we need to clear, not those that we will
438 * actually initialise below. Hence, don't put any more fields after
439 * the tail pointer in struct sk_buff!
440 */
441 memset(skb, 0, offsetof(struct sk_buff, tail));
442 __build_skb_around(skb, data, 0);
443 skb->pfmemalloc = pfmemalloc;
444
445 if (flags & SKB_ALLOC_FCLONE) {
446 struct sk_buff_fclones *fclones;
447
448 fclones = container_of(skb, struct sk_buff_fclones, skb1);
449
450 skb->fclone = SKB_FCLONE_ORIG;
451 refcount_set(&fclones->fclone_ref, 1);
452
453 fclones->skb2.fclone = SKB_FCLONE_CLONE;
454 }
455
456 return skb;
457
458nodata:
459 kmem_cache_free(cache, skb);
460 return NULL;
461}
462EXPORT_SYMBOL(__alloc_skb);
463
464/**
465 * __netdev_alloc_skb - allocate an skbuff for rx on a specific device
466 * @dev: network device to receive on
467 * @len: length to allocate
468 * @gfp_mask: get_free_pages mask, passed to alloc_skb
469 *
470 * Allocate a new &sk_buff and assign it a usage count of one. The
471 * buffer has NET_SKB_PAD headroom built in. Users should allocate
472 * the headroom they think they need without accounting for the
473 * built in space. The built in space is used for optimisations.
474 *
475 * %NULL is returned if there is no free memory.
476 */
477struct sk_buff *__netdev_alloc_skb(struct net_device *dev, unsigned int len,
478 gfp_t gfp_mask)
479{
480 struct page_frag_cache *nc;
481 struct sk_buff *skb;
482 bool pfmemalloc;
483 void *data;
484
485 len += NET_SKB_PAD;
486
487 /* If requested length is either too small or too big,
488 * we use kmalloc() for skb->head allocation.
489 */
490 if (len <= SKB_WITH_OVERHEAD(1024) ||
491 len > SKB_WITH_OVERHEAD(PAGE_SIZE) ||
492 (gfp_mask & (__GFP_DIRECT_RECLAIM | GFP_DMA))) {
493 skb = __alloc_skb(len, gfp_mask, SKB_ALLOC_RX, NUMA_NO_NODE);
494 if (!skb)
495 goto skb_fail;
496 goto skb_success;
497 }
498
499 len += SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
500 len = SKB_DATA_ALIGN(len);
501
502 if (sk_memalloc_socks())
503 gfp_mask |= __GFP_MEMALLOC;
504
505 if (in_irq() || irqs_disabled()) {
506 nc = this_cpu_ptr(&netdev_alloc_cache);
507 data = page_frag_alloc(nc, len, gfp_mask);
508 pfmemalloc = nc->pfmemalloc;
509 } else {
510 local_bh_disable();
511 nc = this_cpu_ptr(&napi_alloc_cache.page);
512 data = page_frag_alloc(nc, len, gfp_mask);
513 pfmemalloc = nc->pfmemalloc;
514 local_bh_enable();
515 }
516
517 if (unlikely(!data))
518 return NULL;
519
520 skb = __build_skb(data, len);
521 if (unlikely(!skb)) {
522 skb_free_frag(data);
523 return NULL;
524 }
525
526 if (pfmemalloc)
527 skb->pfmemalloc = 1;
528 skb->head_frag = 1;
529
530skb_success:
531 skb_reserve(skb, NET_SKB_PAD);
532 skb->dev = dev;
533
534skb_fail:
535 return skb;
536}
537EXPORT_SYMBOL(__netdev_alloc_skb);
538
539/**
540 * __napi_alloc_skb - allocate skbuff for rx in a specific NAPI instance
541 * @napi: napi instance this buffer was allocated for
542 * @len: length to allocate
543 * @gfp_mask: get_free_pages mask, passed to alloc_skb and alloc_pages
544 *
545 * Allocate a new sk_buff for use in NAPI receive. This buffer will
546 * attempt to allocate the head from a special reserved region used
547 * only for NAPI Rx allocation. By doing this we can save several
548 * CPU cycles by avoiding having to disable and re-enable IRQs.
549 *
550 * %NULL is returned if there is no free memory.
551 */
552struct sk_buff *__napi_alloc_skb(struct napi_struct *napi, unsigned int len,
553 gfp_t gfp_mask)
554{
555 struct napi_alloc_cache *nc;
556 struct sk_buff *skb;
557 void *data;
558
559 len += NET_SKB_PAD + NET_IP_ALIGN;
560
561 /* If requested length is either too small or too big,
562 * we use kmalloc() for skb->head allocation.
563 */
564 if (len <= SKB_WITH_OVERHEAD(1024) ||
565 len > SKB_WITH_OVERHEAD(PAGE_SIZE) ||
566 (gfp_mask & (__GFP_DIRECT_RECLAIM | GFP_DMA))) {
567 skb = __alloc_skb(len, gfp_mask, SKB_ALLOC_RX | SKB_ALLOC_NAPI,
568 NUMA_NO_NODE);
569 if (!skb)
570 goto skb_fail;
571 goto skb_success;
572 }
573
574 nc = this_cpu_ptr(&napi_alloc_cache);
575 len += SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
576 len = SKB_DATA_ALIGN(len);
577
578 if (sk_memalloc_socks())
579 gfp_mask |= __GFP_MEMALLOC;
580
581 data = page_frag_alloc(&nc->page, len, gfp_mask);
582 if (unlikely(!data))
583 return NULL;
584
585 skb = __napi_build_skb(data, len);
586 if (unlikely(!skb)) {
587 skb_free_frag(data);
588 return NULL;
589 }
590
591 if (nc->page.pfmemalloc)
592 skb->pfmemalloc = 1;
593 skb->head_frag = 1;
594
595skb_success:
596 skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN);
597 skb->dev = napi->dev;
598
599skb_fail:
600 return skb;
601}
602EXPORT_SYMBOL(__napi_alloc_skb);
603
604void skb_add_rx_frag(struct sk_buff *skb, int i, struct page *page, int off,
605 int size, unsigned int truesize)
606{
607 skb_fill_page_desc(skb, i, page, off, size);
608 skb->len += size;
609 skb->data_len += size;
610 skb->truesize += truesize;
611}
612EXPORT_SYMBOL(skb_add_rx_frag);
613
614void skb_coalesce_rx_frag(struct sk_buff *skb, int i, int size,
615 unsigned int truesize)
616{
617 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
618
619 skb_frag_size_add(frag, size);
620 skb->len += size;
621 skb->data_len += size;
622 skb->truesize += truesize;
623}
624EXPORT_SYMBOL(skb_coalesce_rx_frag);
625
626static void skb_drop_list(struct sk_buff **listp)
627{
628 kfree_skb_list(*listp);
629 *listp = NULL;
630}
631
632static inline void skb_drop_fraglist(struct sk_buff *skb)
633{
634 skb_drop_list(&skb_shinfo(skb)->frag_list);
635}
636
637static void skb_clone_fraglist(struct sk_buff *skb)
638{
639 struct sk_buff *list;
640
641 skb_walk_frags(skb, list)
642 skb_get(list);
643}
644
645static void skb_free_head(struct sk_buff *skb)
646{
647 unsigned char *head = skb->head;
648
649 if (skb->head_frag) {
650 if (skb_pp_recycle(skb, head))
651 return;
652 skb_free_frag(head);
653 } else {
654 kfree(head);
655 }
656}
657
658static void skb_release_data(struct sk_buff *skb)
659{
660 struct skb_shared_info *shinfo = skb_shinfo(skb);
661 int i;
662
663 if (skb->cloned &&
664 atomic_sub_return(skb->nohdr ? (1 << SKB_DATAREF_SHIFT) + 1 : 1,
665 &shinfo->dataref))
666 goto exit;
667
668 skb_zcopy_clear(skb, true);
669
670 for (i = 0; i < shinfo->nr_frags; i++)
671 __skb_frag_unref(&shinfo->frags[i], skb->pp_recycle);
672
673 if (shinfo->frag_list)
674 kfree_skb_list(shinfo->frag_list);
675
676 skb_free_head(skb);
677exit:
678 /* When we clone an SKB we copy the reycling bit. The pp_recycle
679 * bit is only set on the head though, so in order to avoid races
680 * while trying to recycle fragments on __skb_frag_unref() we need
681 * to make one SKB responsible for triggering the recycle path.
682 * So disable the recycling bit if an SKB is cloned and we have
683 * additional references to to the fragmented part of the SKB.
684 * Eventually the last SKB will have the recycling bit set and it's
685 * dataref set to 0, which will trigger the recycling
686 */
687 skb->pp_recycle = 0;
688}
689
690/*
691 * Free an skbuff by memory without cleaning the state.
692 */
693static void kfree_skbmem(struct sk_buff *skb)
694{
695 struct sk_buff_fclones *fclones;
696
697 switch (skb->fclone) {
698 case SKB_FCLONE_UNAVAILABLE:
699 kmem_cache_free(skbuff_head_cache, skb);
700 return;
701
702 case SKB_FCLONE_ORIG:
703 fclones = container_of(skb, struct sk_buff_fclones, skb1);
704
705 /* We usually free the clone (TX completion) before original skb
706 * This test would have no chance to be true for the clone,
707 * while here, branch prediction will be good.
708 */
709 if (refcount_read(&fclones->fclone_ref) == 1)
710 goto fastpath;
711 break;
712
713 default: /* SKB_FCLONE_CLONE */
714 fclones = container_of(skb, struct sk_buff_fclones, skb2);
715 break;
716 }
717 if (!refcount_dec_and_test(&fclones->fclone_ref))
718 return;
719fastpath:
720 kmem_cache_free(skbuff_fclone_cache, fclones);
721}
722
723void skb_release_head_state(struct sk_buff *skb)
724{
725 skb_dst_drop(skb);
726 if (skb->destructor) {
727 WARN_ON(in_irq());
728 skb->destructor(skb);
729 }
730#if IS_ENABLED(CONFIG_NF_CONNTRACK)
731 nf_conntrack_put(skb_nfct(skb));
732#endif
733 skb_ext_put(skb);
734}
735
736/* Free everything but the sk_buff shell. */
737static void skb_release_all(struct sk_buff *skb)
738{
739 skb_release_head_state(skb);
740 if (likely(skb->head))
741 skb_release_data(skb);
742}
743
744/**
745 * __kfree_skb - private function
746 * @skb: buffer
747 *
748 * Free an sk_buff. Release anything attached to the buffer.
749 * Clean the state. This is an internal helper function. Users should
750 * always call kfree_skb
751 */
752
753void __kfree_skb(struct sk_buff *skb)
754{
755 skb_release_all(skb);
756 kfree_skbmem(skb);
757}
758EXPORT_SYMBOL(__kfree_skb);
759
760/**
761 * kfree_skb - free an sk_buff
762 * @skb: buffer to free
763 *
764 * Drop a reference to the buffer and free it if the usage count has
765 * hit zero.
766 */
767void kfree_skb(struct sk_buff *skb)
768{
769 if (!skb_unref(skb))
770 return;
771
772 trace_kfree_skb(skb, __builtin_return_address(0));
773 __kfree_skb(skb);
774}
775EXPORT_SYMBOL(kfree_skb);
776
777void kfree_skb_list(struct sk_buff *segs)
778{
779 while (segs) {
780 struct sk_buff *next = segs->next;
781
782 kfree_skb(segs);
783 segs = next;
784 }
785}
786EXPORT_SYMBOL(kfree_skb_list);
787
788/* Dump skb information and contents.
789 *
790 * Must only be called from net_ratelimit()-ed paths.
791 *
792 * Dumps whole packets if full_pkt, only headers otherwise.
793 */
794void skb_dump(const char *level, const struct sk_buff *skb, bool full_pkt)
795{
796 struct skb_shared_info *sh = skb_shinfo(skb);
797 struct net_device *dev = skb->dev;
798 struct sock *sk = skb->sk;
799 struct sk_buff *list_skb;
800 bool has_mac, has_trans;
801 int headroom, tailroom;
802 int i, len, seg_len;
803
804 if (full_pkt)
805 len = skb->len;
806 else
807 len = min_t(int, skb->len, MAX_HEADER + 128);
808
809 headroom = skb_headroom(skb);
810 tailroom = skb_tailroom(skb);
811
812 has_mac = skb_mac_header_was_set(skb);
813 has_trans = skb_transport_header_was_set(skb);
814
815 printk("%sskb len=%u headroom=%u headlen=%u tailroom=%u\n"
816 "mac=(%d,%d) net=(%d,%d) trans=%d\n"
817 "shinfo(txflags=%u nr_frags=%u gso(size=%hu type=%u segs=%hu))\n"
818 "csum(0x%x ip_summed=%u complete_sw=%u valid=%u level=%u)\n"
819 "hash(0x%x sw=%u l4=%u) proto=0x%04x pkttype=%u iif=%d\n",
820 level, skb->len, headroom, skb_headlen(skb), tailroom,
821 has_mac ? skb->mac_header : -1,
822 has_mac ? skb_mac_header_len(skb) : -1,
823 skb->network_header,
824 has_trans ? skb_network_header_len(skb) : -1,
825 has_trans ? skb->transport_header : -1,
826 sh->tx_flags, sh->nr_frags,
827 sh->gso_size, sh->gso_type, sh->gso_segs,
828 skb->csum, skb->ip_summed, skb->csum_complete_sw,
829 skb->csum_valid, skb->csum_level,
830 skb->hash, skb->sw_hash, skb->l4_hash,
831 ntohs(skb->protocol), skb->pkt_type, skb->skb_iif);
832
833 if (dev)
834 printk("%sdev name=%s feat=0x%pNF\n",
835 level, dev->name, &dev->features);
836 if (sk)
837 printk("%ssk family=%hu type=%u proto=%u\n",
838 level, sk->sk_family, sk->sk_type, sk->sk_protocol);
839
840 if (full_pkt && headroom)
841 print_hex_dump(level, "skb headroom: ", DUMP_PREFIX_OFFSET,
842 16, 1, skb->head, headroom, false);
843
844 seg_len = min_t(int, skb_headlen(skb), len);
845 if (seg_len)
846 print_hex_dump(level, "skb linear: ", DUMP_PREFIX_OFFSET,
847 16, 1, skb->data, seg_len, false);
848 len -= seg_len;
849
850 if (full_pkt && tailroom)
851 print_hex_dump(level, "skb tailroom: ", DUMP_PREFIX_OFFSET,
852 16, 1, skb_tail_pointer(skb), tailroom, false);
853
854 for (i = 0; len && i < skb_shinfo(skb)->nr_frags; i++) {
855 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
856 u32 p_off, p_len, copied;
857 struct page *p;
858 u8 *vaddr;
859
860 skb_frag_foreach_page(frag, skb_frag_off(frag),
861 skb_frag_size(frag), p, p_off, p_len,
862 copied) {
863 seg_len = min_t(int, p_len, len);
864 vaddr = kmap_atomic(p);
865 print_hex_dump(level, "skb frag: ",
866 DUMP_PREFIX_OFFSET,
867 16, 1, vaddr + p_off, seg_len, false);
868 kunmap_atomic(vaddr);
869 len -= seg_len;
870 if (!len)
871 break;
872 }
873 }
874
875 if (full_pkt && skb_has_frag_list(skb)) {
876 printk("skb fraglist:\n");
877 skb_walk_frags(skb, list_skb)
878 skb_dump(level, list_skb, true);
879 }
880}
881EXPORT_SYMBOL(skb_dump);
882
883/**
884 * skb_tx_error - report an sk_buff xmit error
885 * @skb: buffer that triggered an error
886 *
887 * Report xmit error if a device callback is tracking this skb.
888 * skb must be freed afterwards.
889 */
890void skb_tx_error(struct sk_buff *skb)
891{
892 skb_zcopy_clear(skb, true);
893}
894EXPORT_SYMBOL(skb_tx_error);
895
896#ifdef CONFIG_TRACEPOINTS
897/**
898 * consume_skb - free an skbuff
899 * @skb: buffer to free
900 *
901 * Drop a ref to the buffer and free it if the usage count has hit zero
902 * Functions identically to kfree_skb, but kfree_skb assumes that the frame
903 * is being dropped after a failure and notes that
904 */
905void consume_skb(struct sk_buff *skb)
906{
907 if (!skb_unref(skb))
908 return;
909
910 trace_consume_skb(skb);
911 __kfree_skb(skb);
912}
913EXPORT_SYMBOL(consume_skb);
914#endif
915
916/**
917 * __consume_stateless_skb - free an skbuff, assuming it is stateless
918 * @skb: buffer to free
919 *
920 * Alike consume_skb(), but this variant assumes that this is the last
921 * skb reference and all the head states have been already dropped
922 */
923void __consume_stateless_skb(struct sk_buff *skb)
924{
925 trace_consume_skb(skb);
926 skb_release_data(skb);
927 kfree_skbmem(skb);
928}
929
930static void napi_skb_cache_put(struct sk_buff *skb)
931{
932 struct napi_alloc_cache *nc = this_cpu_ptr(&napi_alloc_cache);
933 u32 i;
934
935 kasan_poison_object_data(skbuff_head_cache, skb);
936 nc->skb_cache[nc->skb_count++] = skb;
937
938 if (unlikely(nc->skb_count == NAPI_SKB_CACHE_SIZE)) {
939 for (i = NAPI_SKB_CACHE_HALF; i < NAPI_SKB_CACHE_SIZE; i++)
940 kasan_unpoison_object_data(skbuff_head_cache,
941 nc->skb_cache[i]);
942
943 kmem_cache_free_bulk(skbuff_head_cache, NAPI_SKB_CACHE_HALF,
944 nc->skb_cache + NAPI_SKB_CACHE_HALF);
945 nc->skb_count = NAPI_SKB_CACHE_HALF;
946 }
947}
948
949void __kfree_skb_defer(struct sk_buff *skb)
950{
951 skb_release_all(skb);
952 napi_skb_cache_put(skb);
953}
954
955void napi_skb_free_stolen_head(struct sk_buff *skb)
956{
957 nf_reset_ct(skb);
958 skb_dst_drop(skb);
959 skb_ext_put(skb);
960 napi_skb_cache_put(skb);
961}
962
963void napi_consume_skb(struct sk_buff *skb, int budget)
964{
965 /* Zero budget indicate non-NAPI context called us, like netpoll */
966 if (unlikely(!budget)) {
967 dev_consume_skb_any(skb);
968 return;
969 }
970
971 lockdep_assert_in_softirq();
972
973 if (!skb_unref(skb))
974 return;
975
976 /* if reaching here SKB is ready to free */
977 trace_consume_skb(skb);
978
979 /* if SKB is a clone, don't handle this case */
980 if (skb->fclone != SKB_FCLONE_UNAVAILABLE) {
981 __kfree_skb(skb);
982 return;
983 }
984
985 skb_release_all(skb);
986 napi_skb_cache_put(skb);
987}
988EXPORT_SYMBOL(napi_consume_skb);
989
990/* Make sure a field is enclosed inside headers_start/headers_end section */
991#define CHECK_SKB_FIELD(field) \
992 BUILD_BUG_ON(offsetof(struct sk_buff, field) < \
993 offsetof(struct sk_buff, headers_start)); \
994 BUILD_BUG_ON(offsetof(struct sk_buff, field) > \
995 offsetof(struct sk_buff, headers_end)); \
996
997static void __copy_skb_header(struct sk_buff *new, const struct sk_buff *old)
998{
999 new->tstamp = old->tstamp;
1000 /* We do not copy old->sk */
1001 new->dev = old->dev;
1002 memcpy(new->cb, old->cb, sizeof(old->cb));
1003 skb_dst_copy(new, old);
1004 __skb_ext_copy(new, old);
1005 __nf_copy(new, old, false);
1006
1007 /* Note : this field could be in headers_start/headers_end section
1008 * It is not yet because we do not want to have a 16 bit hole
1009 */
1010 new->queue_mapping = old->queue_mapping;
1011
1012 memcpy(&new->headers_start, &old->headers_start,
1013 offsetof(struct sk_buff, headers_end) -
1014 offsetof(struct sk_buff, headers_start));
1015 CHECK_SKB_FIELD(protocol);
1016 CHECK_SKB_FIELD(csum);
1017 CHECK_SKB_FIELD(hash);
1018 CHECK_SKB_FIELD(priority);
1019 CHECK_SKB_FIELD(skb_iif);
1020 CHECK_SKB_FIELD(vlan_proto);
1021 CHECK_SKB_FIELD(vlan_tci);
1022 CHECK_SKB_FIELD(transport_header);
1023 CHECK_SKB_FIELD(network_header);
1024 CHECK_SKB_FIELD(mac_header);
1025 CHECK_SKB_FIELD(inner_protocol);
1026 CHECK_SKB_FIELD(inner_transport_header);
1027 CHECK_SKB_FIELD(inner_network_header);
1028 CHECK_SKB_FIELD(inner_mac_header);
1029 CHECK_SKB_FIELD(mark);
1030#ifdef CONFIG_NETWORK_SECMARK
1031 CHECK_SKB_FIELD(secmark);
1032#endif
1033#ifdef CONFIG_NET_RX_BUSY_POLL
1034 CHECK_SKB_FIELD(napi_id);
1035#endif
1036#ifdef CONFIG_XPS
1037 CHECK_SKB_FIELD(sender_cpu);
1038#endif
1039#ifdef CONFIG_NET_SCHED
1040 CHECK_SKB_FIELD(tc_index);
1041#endif
1042
1043}
1044
1045/*
1046 * You should not add any new code to this function. Add it to
1047 * __copy_skb_header above instead.
1048 */
1049static struct sk_buff *__skb_clone(struct sk_buff *n, struct sk_buff *skb)
1050{
1051#define C(x) n->x = skb->x
1052
1053 n->next = n->prev = NULL;
1054 n->sk = NULL;
1055 __copy_skb_header(n, skb);
1056
1057 C(len);
1058 C(data_len);
1059 C(mac_len);
1060 n->hdr_len = skb->nohdr ? skb_headroom(skb) : skb->hdr_len;
1061 n->cloned = 1;
1062 n->nohdr = 0;
1063 n->peeked = 0;
1064 C(pfmemalloc);
1065 C(pp_recycle);
1066 n->destructor = NULL;
1067 C(tail);
1068 C(end);
1069 C(head);
1070 C(head_frag);
1071 C(data);
1072 C(truesize);
1073 refcount_set(&n->users, 1);
1074
1075 atomic_inc(&(skb_shinfo(skb)->dataref));
1076 skb->cloned = 1;
1077
1078 return n;
1079#undef C
1080}
1081
1082/**
1083 * alloc_skb_for_msg() - allocate sk_buff to wrap frag list forming a msg
1084 * @first: first sk_buff of the msg
1085 */
1086struct sk_buff *alloc_skb_for_msg(struct sk_buff *first)
1087{
1088 struct sk_buff *n;
1089
1090 n = alloc_skb(0, GFP_ATOMIC);
1091 if (!n)
1092 return NULL;
1093
1094 n->len = first->len;
1095 n->data_len = first->len;
1096 n->truesize = first->truesize;
1097
1098 skb_shinfo(n)->frag_list = first;
1099
1100 __copy_skb_header(n, first);
1101 n->destructor = NULL;
1102
1103 return n;
1104}
1105EXPORT_SYMBOL_GPL(alloc_skb_for_msg);
1106
1107/**
1108 * skb_morph - morph one skb into another
1109 * @dst: the skb to receive the contents
1110 * @src: the skb to supply the contents
1111 *
1112 * This is identical to skb_clone except that the target skb is
1113 * supplied by the user.
1114 *
1115 * The target skb is returned upon exit.
1116 */
1117struct sk_buff *skb_morph(struct sk_buff *dst, struct sk_buff *src)
1118{
1119 skb_release_all(dst);
1120 return __skb_clone(dst, src);
1121}
1122EXPORT_SYMBOL_GPL(skb_morph);
1123
1124int mm_account_pinned_pages(struct mmpin *mmp, size_t size)
1125{
1126 unsigned long max_pg, num_pg, new_pg, old_pg;
1127 struct user_struct *user;
1128
1129 if (capable(CAP_IPC_LOCK) || !size)
1130 return 0;
1131
1132 num_pg = (size >> PAGE_SHIFT) + 2; /* worst case */
1133 max_pg = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
1134 user = mmp->user ? : current_user();
1135
1136 do {
1137 old_pg = atomic_long_read(&user->locked_vm);
1138 new_pg = old_pg + num_pg;
1139 if (new_pg > max_pg)
1140 return -ENOBUFS;
1141 } while (atomic_long_cmpxchg(&user->locked_vm, old_pg, new_pg) !=
1142 old_pg);
1143
1144 if (!mmp->user) {
1145 mmp->user = get_uid(user);
1146 mmp->num_pg = num_pg;
1147 } else {
1148 mmp->num_pg += num_pg;
1149 }
1150
1151 return 0;
1152}
1153EXPORT_SYMBOL_GPL(mm_account_pinned_pages);
1154
1155void mm_unaccount_pinned_pages(struct mmpin *mmp)
1156{
1157 if (mmp->user) {
1158 atomic_long_sub(mmp->num_pg, &mmp->user->locked_vm);
1159 free_uid(mmp->user);
1160 }
1161}
1162EXPORT_SYMBOL_GPL(mm_unaccount_pinned_pages);
1163
1164struct ubuf_info *msg_zerocopy_alloc(struct sock *sk, size_t size)
1165{
1166 struct ubuf_info *uarg;
1167 struct sk_buff *skb;
1168
1169 WARN_ON_ONCE(!in_task());
1170
1171 skb = sock_omalloc(sk, 0, GFP_KERNEL);
1172 if (!skb)
1173 return NULL;
1174
1175 BUILD_BUG_ON(sizeof(*uarg) > sizeof(skb->cb));
1176 uarg = (void *)skb->cb;
1177 uarg->mmp.user = NULL;
1178
1179 if (mm_account_pinned_pages(&uarg->mmp, size)) {
1180 kfree_skb(skb);
1181 return NULL;
1182 }
1183
1184 uarg->callback = msg_zerocopy_callback;
1185 uarg->id = ((u32)atomic_inc_return(&sk->sk_zckey)) - 1;
1186 uarg->len = 1;
1187 uarg->bytelen = size;
1188 uarg->zerocopy = 1;
1189 uarg->flags = SKBFL_ZEROCOPY_FRAG;
1190 refcount_set(&uarg->refcnt, 1);
1191 sock_hold(sk);
1192
1193 return uarg;
1194}
1195EXPORT_SYMBOL_GPL(msg_zerocopy_alloc);
1196
1197static inline struct sk_buff *skb_from_uarg(struct ubuf_info *uarg)
1198{
1199 return container_of((void *)uarg, struct sk_buff, cb);
1200}
1201
1202struct ubuf_info *msg_zerocopy_realloc(struct sock *sk, size_t size,
1203 struct ubuf_info *uarg)
1204{
1205 if (uarg) {
1206 const u32 byte_limit = 1 << 19; /* limit to a few TSO */
1207 u32 bytelen, next;
1208
1209 /* realloc only when socket is locked (TCP, UDP cork),
1210 * so uarg->len and sk_zckey access is serialized
1211 */
1212 if (!sock_owned_by_user(sk)) {
1213 WARN_ON_ONCE(1);
1214 return NULL;
1215 }
1216
1217 bytelen = uarg->bytelen + size;
1218 if (uarg->len == USHRT_MAX - 1 || bytelen > byte_limit) {
1219 /* TCP can create new skb to attach new uarg */
1220 if (sk->sk_type == SOCK_STREAM)
1221 goto new_alloc;
1222 return NULL;
1223 }
1224
1225 next = (u32)atomic_read(&sk->sk_zckey);
1226 if ((u32)(uarg->id + uarg->len) == next) {
1227 if (mm_account_pinned_pages(&uarg->mmp, size))
1228 return NULL;
1229 uarg->len++;
1230 uarg->bytelen = bytelen;
1231 atomic_set(&sk->sk_zckey, ++next);
1232
1233 /* no extra ref when appending to datagram (MSG_MORE) */
1234 if (sk->sk_type == SOCK_STREAM)
1235 net_zcopy_get(uarg);
1236
1237 return uarg;
1238 }
1239 }
1240
1241new_alloc:
1242 return msg_zerocopy_alloc(sk, size);
1243}
1244EXPORT_SYMBOL_GPL(msg_zerocopy_realloc);
1245
1246static bool skb_zerocopy_notify_extend(struct sk_buff *skb, u32 lo, u16 len)
1247{
1248 struct sock_exterr_skb *serr = SKB_EXT_ERR(skb);
1249 u32 old_lo, old_hi;
1250 u64 sum_len;
1251
1252 old_lo = serr->ee.ee_info;
1253 old_hi = serr->ee.ee_data;
1254 sum_len = old_hi - old_lo + 1ULL + len;
1255
1256 if (sum_len >= (1ULL << 32))
1257 return false;
1258
1259 if (lo != old_hi + 1)
1260 return false;
1261
1262 serr->ee.ee_data += len;
1263 return true;
1264}
1265
1266static void __msg_zerocopy_callback(struct ubuf_info *uarg)
1267{
1268 struct sk_buff *tail, *skb = skb_from_uarg(uarg);
1269 struct sock_exterr_skb *serr;
1270 struct sock *sk = skb->sk;
1271 struct sk_buff_head *q;
1272 unsigned long flags;
1273 bool is_zerocopy;
1274 u32 lo, hi;
1275 u16 len;
1276
1277 mm_unaccount_pinned_pages(&uarg->mmp);
1278
1279 /* if !len, there was only 1 call, and it was aborted
1280 * so do not queue a completion notification
1281 */
1282 if (!uarg->len || sock_flag(sk, SOCK_DEAD))
1283 goto release;
1284
1285 len = uarg->len;
1286 lo = uarg->id;
1287 hi = uarg->id + len - 1;
1288 is_zerocopy = uarg->zerocopy;
1289
1290 serr = SKB_EXT_ERR(skb);
1291 memset(serr, 0, sizeof(*serr));
1292 serr->ee.ee_errno = 0;
1293 serr->ee.ee_origin = SO_EE_ORIGIN_ZEROCOPY;
1294 serr->ee.ee_data = hi;
1295 serr->ee.ee_info = lo;
1296 if (!is_zerocopy)
1297 serr->ee.ee_code |= SO_EE_CODE_ZEROCOPY_COPIED;
1298
1299 q = &sk->sk_error_queue;
1300 spin_lock_irqsave(&q->lock, flags);
1301 tail = skb_peek_tail(q);
1302 if (!tail || SKB_EXT_ERR(tail)->ee.ee_origin != SO_EE_ORIGIN_ZEROCOPY ||
1303 !skb_zerocopy_notify_extend(tail, lo, len)) {
1304 __skb_queue_tail(q, skb);
1305 skb = NULL;
1306 }
1307 spin_unlock_irqrestore(&q->lock, flags);
1308
1309 sk_error_report(sk);
1310
1311release:
1312 consume_skb(skb);
1313 sock_put(sk);
1314}
1315
1316void msg_zerocopy_callback(struct sk_buff *skb, struct ubuf_info *uarg,
1317 bool success)
1318{
1319 uarg->zerocopy = uarg->zerocopy & success;
1320
1321 if (refcount_dec_and_test(&uarg->refcnt))
1322 __msg_zerocopy_callback(uarg);
1323}
1324EXPORT_SYMBOL_GPL(msg_zerocopy_callback);
1325
1326void msg_zerocopy_put_abort(struct ubuf_info *uarg, bool have_uref)
1327{
1328 struct sock *sk = skb_from_uarg(uarg)->sk;
1329
1330 atomic_dec(&sk->sk_zckey);
1331 uarg->len--;
1332
1333 if (have_uref)
1334 msg_zerocopy_callback(NULL, uarg, true);
1335}
1336EXPORT_SYMBOL_GPL(msg_zerocopy_put_abort);
1337
1338int skb_zerocopy_iter_dgram(struct sk_buff *skb, struct msghdr *msg, int len)
1339{
1340 return __zerocopy_sg_from_iter(skb->sk, skb, &msg->msg_iter, len);
1341}
1342EXPORT_SYMBOL_GPL(skb_zerocopy_iter_dgram);
1343
1344int skb_zerocopy_iter_stream(struct sock *sk, struct sk_buff *skb,
1345 struct msghdr *msg, int len,
1346 struct ubuf_info *uarg)
1347{
1348 struct ubuf_info *orig_uarg = skb_zcopy(skb);
1349 struct iov_iter orig_iter = msg->msg_iter;
1350 int err, orig_len = skb->len;
1351
1352 /* An skb can only point to one uarg. This edge case happens when
1353 * TCP appends to an skb, but zerocopy_realloc triggered a new alloc.
1354 */
1355 if (orig_uarg && uarg != orig_uarg)
1356 return -EEXIST;
1357
1358 err = __zerocopy_sg_from_iter(sk, skb, &msg->msg_iter, len);
1359 if (err == -EFAULT || (err == -EMSGSIZE && skb->len == orig_len)) {
1360 struct sock *save_sk = skb->sk;
1361
1362 /* Streams do not free skb on error. Reset to prev state. */
1363 msg->msg_iter = orig_iter;
1364 skb->sk = sk;
1365 ___pskb_trim(skb, orig_len);
1366 skb->sk = save_sk;
1367 return err;
1368 }
1369
1370 skb_zcopy_set(skb, uarg, NULL);
1371 return skb->len - orig_len;
1372}
1373EXPORT_SYMBOL_GPL(skb_zerocopy_iter_stream);
1374
1375static int skb_zerocopy_clone(struct sk_buff *nskb, struct sk_buff *orig,
1376 gfp_t gfp_mask)
1377{
1378 if (skb_zcopy(orig)) {
1379 if (skb_zcopy(nskb)) {
1380 /* !gfp_mask callers are verified to !skb_zcopy(nskb) */
1381 if (!gfp_mask) {
1382 WARN_ON_ONCE(1);
1383 return -ENOMEM;
1384 }
1385 if (skb_uarg(nskb) == skb_uarg(orig))
1386 return 0;
1387 if (skb_copy_ubufs(nskb, GFP_ATOMIC))
1388 return -EIO;
1389 }
1390 skb_zcopy_set(nskb, skb_uarg(orig), NULL);
1391 }
1392 return 0;
1393}
1394
1395/**
1396 * skb_copy_ubufs - copy userspace skb frags buffers to kernel
1397 * @skb: the skb to modify
1398 * @gfp_mask: allocation priority
1399 *
1400 * This must be called on skb with SKBFL_ZEROCOPY_ENABLE.
1401 * It will copy all frags into kernel and drop the reference
1402 * to userspace pages.
1403 *
1404 * If this function is called from an interrupt gfp_mask() must be
1405 * %GFP_ATOMIC.
1406 *
1407 * Returns 0 on success or a negative error code on failure
1408 * to allocate kernel memory to copy to.
1409 */
1410int skb_copy_ubufs(struct sk_buff *skb, gfp_t gfp_mask)
1411{
1412 int num_frags = skb_shinfo(skb)->nr_frags;
1413 struct page *page, *head = NULL;
1414 int i, new_frags;
1415 u32 d_off;
1416
1417 if (skb_shared(skb) || skb_unclone(skb, gfp_mask))
1418 return -EINVAL;
1419
1420 if (!num_frags)
1421 goto release;
1422
1423 new_frags = (__skb_pagelen(skb) + PAGE_SIZE - 1) >> PAGE_SHIFT;
1424 for (i = 0; i < new_frags; i++) {
1425 page = alloc_page(gfp_mask);
1426 if (!page) {
1427 while (head) {
1428 struct page *next = (struct page *)page_private(head);
1429 put_page(head);
1430 head = next;
1431 }
1432 return -ENOMEM;
1433 }
1434 set_page_private(page, (unsigned long)head);
1435 head = page;
1436 }
1437
1438 page = head;
1439 d_off = 0;
1440 for (i = 0; i < num_frags; i++) {
1441 skb_frag_t *f = &skb_shinfo(skb)->frags[i];
1442 u32 p_off, p_len, copied;
1443 struct page *p;
1444 u8 *vaddr;
1445
1446 skb_frag_foreach_page(f, skb_frag_off(f), skb_frag_size(f),
1447 p, p_off, p_len, copied) {
1448 u32 copy, done = 0;
1449 vaddr = kmap_atomic(p);
1450
1451 while (done < p_len) {
1452 if (d_off == PAGE_SIZE) {
1453 d_off = 0;
1454 page = (struct page *)page_private(page);
1455 }
1456 copy = min_t(u32, PAGE_SIZE - d_off, p_len - done);
1457 memcpy(page_address(page) + d_off,
1458 vaddr + p_off + done, copy);
1459 done += copy;
1460 d_off += copy;
1461 }
1462 kunmap_atomic(vaddr);
1463 }
1464 }
1465
1466 /* skb frags release userspace buffers */
1467 for (i = 0; i < num_frags; i++)
1468 skb_frag_unref(skb, i);
1469
1470 /* skb frags point to kernel buffers */
1471 for (i = 0; i < new_frags - 1; i++) {
1472 __skb_fill_page_desc(skb, i, head, 0, PAGE_SIZE);
1473 head = (struct page *)page_private(head);
1474 }
1475 __skb_fill_page_desc(skb, new_frags - 1, head, 0, d_off);
1476 skb_shinfo(skb)->nr_frags = new_frags;
1477
1478release:
1479 skb_zcopy_clear(skb, false);
1480 return 0;
1481}
1482EXPORT_SYMBOL_GPL(skb_copy_ubufs);
1483
1484/**
1485 * skb_clone - duplicate an sk_buff
1486 * @skb: buffer to clone
1487 * @gfp_mask: allocation priority
1488 *
1489 * Duplicate an &sk_buff. The new one is not owned by a socket. Both
1490 * copies share the same packet data but not structure. The new
1491 * buffer has a reference count of 1. If the allocation fails the
1492 * function returns %NULL otherwise the new buffer is returned.
1493 *
1494 * If this function is called from an interrupt gfp_mask() must be
1495 * %GFP_ATOMIC.
1496 */
1497
1498struct sk_buff *skb_clone(struct sk_buff *skb, gfp_t gfp_mask)
1499{
1500 struct sk_buff_fclones *fclones = container_of(skb,
1501 struct sk_buff_fclones,
1502 skb1);
1503 struct sk_buff *n;
1504
1505 if (skb_orphan_frags(skb, gfp_mask))
1506 return NULL;
1507
1508 if (skb->fclone == SKB_FCLONE_ORIG &&
1509 refcount_read(&fclones->fclone_ref) == 1) {
1510 n = &fclones->skb2;
1511 refcount_set(&fclones->fclone_ref, 2);
1512 } else {
1513 if (skb_pfmemalloc(skb))
1514 gfp_mask |= __GFP_MEMALLOC;
1515
1516 n = kmem_cache_alloc(skbuff_head_cache, gfp_mask);
1517 if (!n)
1518 return NULL;
1519
1520 n->fclone = SKB_FCLONE_UNAVAILABLE;
1521 }
1522
1523 return __skb_clone(n, skb);
1524}
1525EXPORT_SYMBOL(skb_clone);
1526
1527void skb_headers_offset_update(struct sk_buff *skb, int off)
1528{
1529 /* Only adjust this if it actually is csum_start rather than csum */
1530 if (skb->ip_summed == CHECKSUM_PARTIAL)
1531 skb->csum_start += off;
1532 /* {transport,network,mac}_header and tail are relative to skb->head */
1533 skb->transport_header += off;
1534 skb->network_header += off;
1535 if (skb_mac_header_was_set(skb))
1536 skb->mac_header += off;
1537 skb->inner_transport_header += off;
1538 skb->inner_network_header += off;
1539 skb->inner_mac_header += off;
1540}
1541EXPORT_SYMBOL(skb_headers_offset_update);
1542
1543void skb_copy_header(struct sk_buff *new, const struct sk_buff *old)
1544{
1545 __copy_skb_header(new, old);
1546
1547 skb_shinfo(new)->gso_size = skb_shinfo(old)->gso_size;
1548 skb_shinfo(new)->gso_segs = skb_shinfo(old)->gso_segs;
1549 skb_shinfo(new)->gso_type = skb_shinfo(old)->gso_type;
1550}
1551EXPORT_SYMBOL(skb_copy_header);
1552
1553static inline int skb_alloc_rx_flag(const struct sk_buff *skb)
1554{
1555 if (skb_pfmemalloc(skb))
1556 return SKB_ALLOC_RX;
1557 return 0;
1558}
1559
1560/**
1561 * skb_copy - create private copy of an sk_buff
1562 * @skb: buffer to copy
1563 * @gfp_mask: allocation priority
1564 *
1565 * Make a copy of both an &sk_buff and its data. This is used when the
1566 * caller wishes to modify the data and needs a private copy of the
1567 * data to alter. Returns %NULL on failure or the pointer to the buffer
1568 * on success. The returned buffer has a reference count of 1.
1569 *
1570 * As by-product this function converts non-linear &sk_buff to linear
1571 * one, so that &sk_buff becomes completely private and caller is allowed
1572 * to modify all the data of returned buffer. This means that this
1573 * function is not recommended for use in circumstances when only
1574 * header is going to be modified. Use pskb_copy() instead.
1575 */
1576
1577struct sk_buff *skb_copy(const struct sk_buff *skb, gfp_t gfp_mask)
1578{
1579 int headerlen = skb_headroom(skb);
1580 unsigned int size = skb_end_offset(skb) + skb->data_len;
1581 struct sk_buff *n = __alloc_skb(size, gfp_mask,
1582 skb_alloc_rx_flag(skb), NUMA_NO_NODE);
1583
1584 if (!n)
1585 return NULL;
1586
1587 /* Set the data pointer */
1588 skb_reserve(n, headerlen);
1589 /* Set the tail pointer and length */
1590 skb_put(n, skb->len);
1591
1592 BUG_ON(skb_copy_bits(skb, -headerlen, n->head, headerlen + skb->len));
1593
1594 skb_copy_header(n, skb);
1595 return n;
1596}
1597EXPORT_SYMBOL(skb_copy);
1598
1599/**
1600 * __pskb_copy_fclone - create copy of an sk_buff with private head.
1601 * @skb: buffer to copy
1602 * @headroom: headroom of new skb
1603 * @gfp_mask: allocation priority
1604 * @fclone: if true allocate the copy of the skb from the fclone
1605 * cache instead of the head cache; it is recommended to set this
1606 * to true for the cases where the copy will likely be cloned
1607 *
1608 * Make a copy of both an &sk_buff and part of its data, located
1609 * in header. Fragmented data remain shared. This is used when
1610 * the caller wishes to modify only header of &sk_buff and needs
1611 * private copy of the header to alter. Returns %NULL on failure
1612 * or the pointer to the buffer on success.
1613 * The returned buffer has a reference count of 1.
1614 */
1615
1616struct sk_buff *__pskb_copy_fclone(struct sk_buff *skb, int headroom,
1617 gfp_t gfp_mask, bool fclone)
1618{
1619 unsigned int size = skb_headlen(skb) + headroom;
1620 int flags = skb_alloc_rx_flag(skb) | (fclone ? SKB_ALLOC_FCLONE : 0);
1621 struct sk_buff *n = __alloc_skb(size, gfp_mask, flags, NUMA_NO_NODE);
1622
1623 if (!n)
1624 goto out;
1625
1626 /* Set the data pointer */
1627 skb_reserve(n, headroom);
1628 /* Set the tail pointer and length */
1629 skb_put(n, skb_headlen(skb));
1630 /* Copy the bytes */
1631 skb_copy_from_linear_data(skb, n->data, n->len);
1632
1633 n->truesize += skb->data_len;
1634 n->data_len = skb->data_len;
1635 n->len = skb->len;
1636
1637 if (skb_shinfo(skb)->nr_frags) {
1638 int i;
1639
1640 if (skb_orphan_frags(skb, gfp_mask) ||
1641 skb_zerocopy_clone(n, skb, gfp_mask)) {
1642 kfree_skb(n);
1643 n = NULL;
1644 goto out;
1645 }
1646 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
1647 skb_shinfo(n)->frags[i] = skb_shinfo(skb)->frags[i];
1648 skb_frag_ref(skb, i);
1649 }
1650 skb_shinfo(n)->nr_frags = i;
1651 }
1652
1653 if (skb_has_frag_list(skb)) {
1654 skb_shinfo(n)->frag_list = skb_shinfo(skb)->frag_list;
1655 skb_clone_fraglist(n);
1656 }
1657
1658 skb_copy_header(n, skb);
1659out:
1660 return n;
1661}
1662EXPORT_SYMBOL(__pskb_copy_fclone);
1663
1664/**
1665 * pskb_expand_head - reallocate header of &sk_buff
1666 * @skb: buffer to reallocate
1667 * @nhead: room to add at head
1668 * @ntail: room to add at tail
1669 * @gfp_mask: allocation priority
1670 *
1671 * Expands (or creates identical copy, if @nhead and @ntail are zero)
1672 * header of @skb. &sk_buff itself is not changed. &sk_buff MUST have
1673 * reference count of 1. Returns zero in the case of success or error,
1674 * if expansion failed. In the last case, &sk_buff is not changed.
1675 *
1676 * All the pointers pointing into skb header may change and must be
1677 * reloaded after call to this function.
1678 */
1679
1680int pskb_expand_head(struct sk_buff *skb, int nhead, int ntail,
1681 gfp_t gfp_mask)
1682{
1683 int i, osize = skb_end_offset(skb);
1684 int size = osize + nhead + ntail;
1685 long off;
1686 u8 *data;
1687
1688 BUG_ON(nhead < 0);
1689
1690 BUG_ON(skb_shared(skb));
1691
1692 size = SKB_DATA_ALIGN(size);
1693
1694 if (skb_pfmemalloc(skb))
1695 gfp_mask |= __GFP_MEMALLOC;
1696 data = kmalloc_reserve(size + SKB_DATA_ALIGN(sizeof(struct skb_shared_info)),
1697 gfp_mask, NUMA_NO_NODE, NULL);
1698 if (!data)
1699 goto nodata;
1700 size = SKB_WITH_OVERHEAD(ksize(data));
1701
1702 /* Copy only real data... and, alas, header. This should be
1703 * optimized for the cases when header is void.
1704 */
1705 memcpy(data + nhead, skb->head, skb_tail_pointer(skb) - skb->head);
1706
1707 memcpy((struct skb_shared_info *)(data + size),
1708 skb_shinfo(skb),
1709 offsetof(struct skb_shared_info, frags[skb_shinfo(skb)->nr_frags]));
1710
1711 /*
1712 * if shinfo is shared we must drop the old head gracefully, but if it
1713 * is not we can just drop the old head and let the existing refcount
1714 * be since all we did is relocate the values
1715 */
1716 if (skb_cloned(skb)) {
1717 if (skb_orphan_frags(skb, gfp_mask))
1718 goto nofrags;
1719 if (skb_zcopy(skb))
1720 refcount_inc(&skb_uarg(skb)->refcnt);
1721 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
1722 skb_frag_ref(skb, i);
1723
1724 if (skb_has_frag_list(skb))
1725 skb_clone_fraglist(skb);
1726
1727 skb_release_data(skb);
1728 } else {
1729 skb_free_head(skb);
1730 }
1731 off = (data + nhead) - skb->head;
1732
1733 skb->head = data;
1734 skb->head_frag = 0;
1735 skb->data += off;
1736#ifdef NET_SKBUFF_DATA_USES_OFFSET
1737 skb->end = size;
1738 off = nhead;
1739#else
1740 skb->end = skb->head + size;
1741#endif
1742 skb->tail += off;
1743 skb_headers_offset_update(skb, nhead);
1744 skb->cloned = 0;
1745 skb->hdr_len = 0;
1746 skb->nohdr = 0;
1747 atomic_set(&skb_shinfo(skb)->dataref, 1);
1748
1749 skb_metadata_clear(skb);
1750
1751 /* It is not generally safe to change skb->truesize.
1752 * For the moment, we really care of rx path, or
1753 * when skb is orphaned (not attached to a socket).
1754 */
1755 if (!skb->sk || skb->destructor == sock_edemux)
1756 skb->truesize += size - osize;
1757
1758 return 0;
1759
1760nofrags:
1761 kfree(data);
1762nodata:
1763 return -ENOMEM;
1764}
1765EXPORT_SYMBOL(pskb_expand_head);
1766
1767/* Make private copy of skb with writable head and some headroom */
1768
1769struct sk_buff *skb_realloc_headroom(struct sk_buff *skb, unsigned int headroom)
1770{
1771 struct sk_buff *skb2;
1772 int delta = headroom - skb_headroom(skb);
1773
1774 if (delta <= 0)
1775 skb2 = pskb_copy(skb, GFP_ATOMIC);
1776 else {
1777 skb2 = skb_clone(skb, GFP_ATOMIC);
1778 if (skb2 && pskb_expand_head(skb2, SKB_DATA_ALIGN(delta), 0,
1779 GFP_ATOMIC)) {
1780 kfree_skb(skb2);
1781 skb2 = NULL;
1782 }
1783 }
1784 return skb2;
1785}
1786EXPORT_SYMBOL(skb_realloc_headroom);
1787
1788/**
1789 * skb_copy_expand - copy and expand sk_buff
1790 * @skb: buffer to copy
1791 * @newheadroom: new free bytes at head
1792 * @newtailroom: new free bytes at tail
1793 * @gfp_mask: allocation priority
1794 *
1795 * Make a copy of both an &sk_buff and its data and while doing so
1796 * allocate additional space.
1797 *
1798 * This is used when the caller wishes to modify the data and needs a
1799 * private copy of the data to alter as well as more space for new fields.
1800 * Returns %NULL on failure or the pointer to the buffer
1801 * on success. The returned buffer has a reference count of 1.
1802 *
1803 * You must pass %GFP_ATOMIC as the allocation priority if this function
1804 * is called from an interrupt.
1805 */
1806struct sk_buff *skb_copy_expand(const struct sk_buff *skb,
1807 int newheadroom, int newtailroom,
1808 gfp_t gfp_mask)
1809{
1810 /*
1811 * Allocate the copy buffer
1812 */
1813 struct sk_buff *n = __alloc_skb(newheadroom + skb->len + newtailroom,
1814 gfp_mask, skb_alloc_rx_flag(skb),
1815 NUMA_NO_NODE);
1816 int oldheadroom = skb_headroom(skb);
1817 int head_copy_len, head_copy_off;
1818
1819 if (!n)
1820 return NULL;
1821
1822 skb_reserve(n, newheadroom);
1823
1824 /* Set the tail pointer and length */
1825 skb_put(n, skb->len);
1826
1827 head_copy_len = oldheadroom;
1828 head_copy_off = 0;
1829 if (newheadroom <= head_copy_len)
1830 head_copy_len = newheadroom;
1831 else
1832 head_copy_off = newheadroom - head_copy_len;
1833
1834 /* Copy the linear header and data. */
1835 BUG_ON(skb_copy_bits(skb, -head_copy_len, n->head + head_copy_off,
1836 skb->len + head_copy_len));
1837
1838 skb_copy_header(n, skb);
1839
1840 skb_headers_offset_update(n, newheadroom - oldheadroom);
1841
1842 return n;
1843}
1844EXPORT_SYMBOL(skb_copy_expand);
1845
1846/**
1847 * __skb_pad - zero pad the tail of an skb
1848 * @skb: buffer to pad
1849 * @pad: space to pad
1850 * @free_on_error: free buffer on error
1851 *
1852 * Ensure that a buffer is followed by a padding area that is zero
1853 * filled. Used by network drivers which may DMA or transfer data
1854 * beyond the buffer end onto the wire.
1855 *
1856 * May return error in out of memory cases. The skb is freed on error
1857 * if @free_on_error is true.
1858 */
1859
1860int __skb_pad(struct sk_buff *skb, int pad, bool free_on_error)
1861{
1862 int err;
1863 int ntail;
1864
1865 /* If the skbuff is non linear tailroom is always zero.. */
1866 if (!skb_cloned(skb) && skb_tailroom(skb) >= pad) {
1867 memset(skb->data+skb->len, 0, pad);
1868 return 0;
1869 }
1870
1871 ntail = skb->data_len + pad - (skb->end - skb->tail);
1872 if (likely(skb_cloned(skb) || ntail > 0)) {
1873 err = pskb_expand_head(skb, 0, ntail, GFP_ATOMIC);
1874 if (unlikely(err))
1875 goto free_skb;
1876 }
1877
1878 /* FIXME: The use of this function with non-linear skb's really needs
1879 * to be audited.
1880 */
1881 err = skb_linearize(skb);
1882 if (unlikely(err))
1883 goto free_skb;
1884
1885 memset(skb->data + skb->len, 0, pad);
1886 return 0;
1887
1888free_skb:
1889 if (free_on_error)
1890 kfree_skb(skb);
1891 return err;
1892}
1893EXPORT_SYMBOL(__skb_pad);
1894
1895/**
1896 * pskb_put - add data to the tail of a potentially fragmented buffer
1897 * @skb: start of the buffer to use
1898 * @tail: tail fragment of the buffer to use
1899 * @len: amount of data to add
1900 *
1901 * This function extends the used data area of the potentially
1902 * fragmented buffer. @tail must be the last fragment of @skb -- or
1903 * @skb itself. If this would exceed the total buffer size the kernel
1904 * will panic. A pointer to the first byte of the extra data is
1905 * returned.
1906 */
1907
1908void *pskb_put(struct sk_buff *skb, struct sk_buff *tail, int len)
1909{
1910 if (tail != skb) {
1911 skb->data_len += len;
1912 skb->len += len;
1913 }
1914 return skb_put(tail, len);
1915}
1916EXPORT_SYMBOL_GPL(pskb_put);
1917
1918/**
1919 * skb_put - add data to a buffer
1920 * @skb: buffer to use
1921 * @len: amount of data to add
1922 *
1923 * This function extends the used data area of the buffer. If this would
1924 * exceed the total buffer size the kernel will panic. A pointer to the
1925 * first byte of the extra data is returned.
1926 */
1927void *skb_put(struct sk_buff *skb, unsigned int len)
1928{
1929 void *tmp = skb_tail_pointer(skb);
1930 SKB_LINEAR_ASSERT(skb);
1931 skb->tail += len;
1932 skb->len += len;
1933 if (unlikely(skb->tail > skb->end))
1934 skb_over_panic(skb, len, __builtin_return_address(0));
1935 return tmp;
1936}
1937EXPORT_SYMBOL(skb_put);
1938
1939/**
1940 * skb_push - add data to the start of a buffer
1941 * @skb: buffer to use
1942 * @len: amount of data to add
1943 *
1944 * This function extends the used data area of the buffer at the buffer
1945 * start. If this would exceed the total buffer headroom the kernel will
1946 * panic. A pointer to the first byte of the extra data is returned.
1947 */
1948void *skb_push(struct sk_buff *skb, unsigned int len)
1949{
1950 skb->data -= len;
1951 skb->len += len;
1952 if (unlikely(skb->data < skb->head))
1953 skb_under_panic(skb, len, __builtin_return_address(0));
1954 return skb->data;
1955}
1956EXPORT_SYMBOL(skb_push);
1957
1958/**
1959 * skb_pull - remove data from the start of a buffer
1960 * @skb: buffer to use
1961 * @len: amount of data to remove
1962 *
1963 * This function removes data from the start of a buffer, returning
1964 * the memory to the headroom. A pointer to the next data in the buffer
1965 * is returned. Once the data has been pulled future pushes will overwrite
1966 * the old data.
1967 */
1968void *skb_pull(struct sk_buff *skb, unsigned int len)
1969{
1970 return skb_pull_inline(skb, len);
1971}
1972EXPORT_SYMBOL(skb_pull);
1973
1974/**
1975 * skb_trim - remove end from a buffer
1976 * @skb: buffer to alter
1977 * @len: new length
1978 *
1979 * Cut the length of a buffer down by removing data from the tail. If
1980 * the buffer is already under the length specified it is not modified.
1981 * The skb must be linear.
1982 */
1983void skb_trim(struct sk_buff *skb, unsigned int len)
1984{
1985 if (skb->len > len)
1986 __skb_trim(skb, len);
1987}
1988EXPORT_SYMBOL(skb_trim);
1989
1990/* Trims skb to length len. It can change skb pointers.
1991 */
1992
1993int ___pskb_trim(struct sk_buff *skb, unsigned int len)
1994{
1995 struct sk_buff **fragp;
1996 struct sk_buff *frag;
1997 int offset = skb_headlen(skb);
1998 int nfrags = skb_shinfo(skb)->nr_frags;
1999 int i;
2000 int err;
2001
2002 if (skb_cloned(skb) &&
2003 unlikely((err = pskb_expand_head(skb, 0, 0, GFP_ATOMIC))))
2004 return err;
2005
2006 i = 0;
2007 if (offset >= len)
2008 goto drop_pages;
2009
2010 for (; i < nfrags; i++) {
2011 int end = offset + skb_frag_size(&skb_shinfo(skb)->frags[i]);
2012
2013 if (end < len) {
2014 offset = end;
2015 continue;
2016 }
2017
2018 skb_frag_size_set(&skb_shinfo(skb)->frags[i++], len - offset);
2019
2020drop_pages:
2021 skb_shinfo(skb)->nr_frags = i;
2022
2023 for (; i < nfrags; i++)
2024 skb_frag_unref(skb, i);
2025
2026 if (skb_has_frag_list(skb))
2027 skb_drop_fraglist(skb);
2028 goto done;
2029 }
2030
2031 for (fragp = &skb_shinfo(skb)->frag_list; (frag = *fragp);
2032 fragp = &frag->next) {
2033 int end = offset + frag->len;
2034
2035 if (skb_shared(frag)) {
2036 struct sk_buff *nfrag;
2037
2038 nfrag = skb_clone(frag, GFP_ATOMIC);
2039 if (unlikely(!nfrag))
2040 return -ENOMEM;
2041
2042 nfrag->next = frag->next;
2043 consume_skb(frag);
2044 frag = nfrag;
2045 *fragp = frag;
2046 }
2047
2048 if (end < len) {
2049 offset = end;
2050 continue;
2051 }
2052
2053 if (end > len &&
2054 unlikely((err = pskb_trim(frag, len - offset))))
2055 return err;
2056
2057 if (frag->next)
2058 skb_drop_list(&frag->next);
2059 break;
2060 }
2061
2062done:
2063 if (len > skb_headlen(skb)) {
2064 skb->data_len -= skb->len - len;
2065 skb->len = len;
2066 } else {
2067 skb->len = len;
2068 skb->data_len = 0;
2069 skb_set_tail_pointer(skb, len);
2070 }
2071
2072 if (!skb->sk || skb->destructor == sock_edemux)
2073 skb_condense(skb);
2074 return 0;
2075}
2076EXPORT_SYMBOL(___pskb_trim);
2077
2078/* Note : use pskb_trim_rcsum() instead of calling this directly
2079 */
2080int pskb_trim_rcsum_slow(struct sk_buff *skb, unsigned int len)
2081{
2082 if (skb->ip_summed == CHECKSUM_COMPLETE) {
2083 int delta = skb->len - len;
2084
2085 skb->csum = csum_block_sub(skb->csum,
2086 skb_checksum(skb, len, delta, 0),
2087 len);
2088 } else if (skb->ip_summed == CHECKSUM_PARTIAL) {
2089 int hdlen = (len > skb_headlen(skb)) ? skb_headlen(skb) : len;
2090 int offset = skb_checksum_start_offset(skb) + skb->csum_offset;
2091
2092 if (offset + sizeof(__sum16) > hdlen)
2093 return -EINVAL;
2094 }
2095 return __pskb_trim(skb, len);
2096}
2097EXPORT_SYMBOL(pskb_trim_rcsum_slow);
2098
2099/**
2100 * __pskb_pull_tail - advance tail of skb header
2101 * @skb: buffer to reallocate
2102 * @delta: number of bytes to advance tail
2103 *
2104 * The function makes a sense only on a fragmented &sk_buff,
2105 * it expands header moving its tail forward and copying necessary
2106 * data from fragmented part.
2107 *
2108 * &sk_buff MUST have reference count of 1.
2109 *
2110 * Returns %NULL (and &sk_buff does not change) if pull failed
2111 * or value of new tail of skb in the case of success.
2112 *
2113 * All the pointers pointing into skb header may change and must be
2114 * reloaded after call to this function.
2115 */
2116
2117/* Moves tail of skb head forward, copying data from fragmented part,
2118 * when it is necessary.
2119 * 1. It may fail due to malloc failure.
2120 * 2. It may change skb pointers.
2121 *
2122 * It is pretty complicated. Luckily, it is called only in exceptional cases.
2123 */
2124void *__pskb_pull_tail(struct sk_buff *skb, int delta)
2125{
2126 /* If skb has not enough free space at tail, get new one
2127 * plus 128 bytes for future expansions. If we have enough
2128 * room at tail, reallocate without expansion only if skb is cloned.
2129 */
2130 int i, k, eat = (skb->tail + delta) - skb->end;
2131
2132 if (eat > 0 || skb_cloned(skb)) {
2133 if (pskb_expand_head(skb, 0, eat > 0 ? eat + 128 : 0,
2134 GFP_ATOMIC))
2135 return NULL;
2136 }
2137
2138 BUG_ON(skb_copy_bits(skb, skb_headlen(skb),
2139 skb_tail_pointer(skb), delta));
2140
2141 /* Optimization: no fragments, no reasons to preestimate
2142 * size of pulled pages. Superb.
2143 */
2144 if (!skb_has_frag_list(skb))
2145 goto pull_pages;
2146
2147 /* Estimate size of pulled pages. */
2148 eat = delta;
2149 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
2150 int size = skb_frag_size(&skb_shinfo(skb)->frags[i]);
2151
2152 if (size >= eat)
2153 goto pull_pages;
2154 eat -= size;
2155 }
2156
2157 /* If we need update frag list, we are in troubles.
2158 * Certainly, it is possible to add an offset to skb data,
2159 * but taking into account that pulling is expected to
2160 * be very rare operation, it is worth to fight against
2161 * further bloating skb head and crucify ourselves here instead.
2162 * Pure masohism, indeed. 8)8)
2163 */
2164 if (eat) {
2165 struct sk_buff *list = skb_shinfo(skb)->frag_list;
2166 struct sk_buff *clone = NULL;
2167 struct sk_buff *insp = NULL;
2168
2169 do {
2170 if (list->len <= eat) {
2171 /* Eaten as whole. */
2172 eat -= list->len;
2173 list = list->next;
2174 insp = list;
2175 } else {
2176 /* Eaten partially. */
2177
2178 if (skb_shared(list)) {
2179 /* Sucks! We need to fork list. :-( */
2180 clone = skb_clone(list, GFP_ATOMIC);
2181 if (!clone)
2182 return NULL;
2183 insp = list->next;
2184 list = clone;
2185 } else {
2186 /* This may be pulled without
2187 * problems. */
2188 insp = list;
2189 }
2190 if (!pskb_pull(list, eat)) {
2191 kfree_skb(clone);
2192 return NULL;
2193 }
2194 break;
2195 }
2196 } while (eat);
2197
2198 /* Free pulled out fragments. */
2199 while ((list = skb_shinfo(skb)->frag_list) != insp) {
2200 skb_shinfo(skb)->frag_list = list->next;
2201 kfree_skb(list);
2202 }
2203 /* And insert new clone at head. */
2204 if (clone) {
2205 clone->next = list;
2206 skb_shinfo(skb)->frag_list = clone;
2207 }
2208 }
2209 /* Success! Now we may commit changes to skb data. */
2210
2211pull_pages:
2212 eat = delta;
2213 k = 0;
2214 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
2215 int size = skb_frag_size(&skb_shinfo(skb)->frags[i]);
2216
2217 if (size <= eat) {
2218 skb_frag_unref(skb, i);
2219 eat -= size;
2220 } else {
2221 skb_frag_t *frag = &skb_shinfo(skb)->frags[k];
2222
2223 *frag = skb_shinfo(skb)->frags[i];
2224 if (eat) {
2225 skb_frag_off_add(frag, eat);
2226 skb_frag_size_sub(frag, eat);
2227 if (!i)
2228 goto end;
2229 eat = 0;
2230 }
2231 k++;
2232 }
2233 }
2234 skb_shinfo(skb)->nr_frags = k;
2235
2236end:
2237 skb->tail += delta;
2238 skb->data_len -= delta;
2239
2240 if (!skb->data_len)
2241 skb_zcopy_clear(skb, false);
2242
2243 return skb_tail_pointer(skb);
2244}
2245EXPORT_SYMBOL(__pskb_pull_tail);
2246
2247/**
2248 * skb_copy_bits - copy bits from skb to kernel buffer
2249 * @skb: source skb
2250 * @offset: offset in source
2251 * @to: destination buffer
2252 * @len: number of bytes to copy
2253 *
2254 * Copy the specified number of bytes from the source skb to the
2255 * destination buffer.
2256 *
2257 * CAUTION ! :
2258 * If its prototype is ever changed,
2259 * check arch/{*}/net/{*}.S files,
2260 * since it is called from BPF assembly code.
2261 */
2262int skb_copy_bits(const struct sk_buff *skb, int offset, void *to, int len)
2263{
2264 int start = skb_headlen(skb);
2265 struct sk_buff *frag_iter;
2266 int i, copy;
2267
2268 if (offset > (int)skb->len - len)
2269 goto fault;
2270
2271 /* Copy header. */
2272 if ((copy = start - offset) > 0) {
2273 if (copy > len)
2274 copy = len;
2275 skb_copy_from_linear_data_offset(skb, offset, to, copy);
2276 if ((len -= copy) == 0)
2277 return 0;
2278 offset += copy;
2279 to += copy;
2280 }
2281
2282 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
2283 int end;
2284 skb_frag_t *f = &skb_shinfo(skb)->frags[i];
2285
2286 WARN_ON(start > offset + len);
2287
2288 end = start + skb_frag_size(f);
2289 if ((copy = end - offset) > 0) {
2290 u32 p_off, p_len, copied;
2291 struct page *p;
2292 u8 *vaddr;
2293
2294 if (copy > len)
2295 copy = len;
2296
2297 skb_frag_foreach_page(f,
2298 skb_frag_off(f) + offset - start,
2299 copy, p, p_off, p_len, copied) {
2300 vaddr = kmap_atomic(p);
2301 memcpy(to + copied, vaddr + p_off, p_len);
2302 kunmap_atomic(vaddr);
2303 }
2304
2305 if ((len -= copy) == 0)
2306 return 0;
2307 offset += copy;
2308 to += copy;
2309 }
2310 start = end;
2311 }
2312
2313 skb_walk_frags(skb, frag_iter) {
2314 int end;
2315
2316 WARN_ON(start > offset + len);
2317
2318 end = start + frag_iter->len;
2319 if ((copy = end - offset) > 0) {
2320 if (copy > len)
2321 copy = len;
2322 if (skb_copy_bits(frag_iter, offset - start, to, copy))
2323 goto fault;
2324 if ((len -= copy) == 0)
2325 return 0;
2326 offset += copy;
2327 to += copy;
2328 }
2329 start = end;
2330 }
2331
2332 if (!len)
2333 return 0;
2334
2335fault:
2336 return -EFAULT;
2337}
2338EXPORT_SYMBOL(skb_copy_bits);
2339
2340/*
2341 * Callback from splice_to_pipe(), if we need to release some pages
2342 * at the end of the spd in case we error'ed out in filling the pipe.
2343 */
2344static void sock_spd_release(struct splice_pipe_desc *spd, unsigned int i)
2345{
2346 put_page(spd->pages[i]);
2347}
2348
2349static struct page *linear_to_page(struct page *page, unsigned int *len,
2350 unsigned int *offset,
2351 struct sock *sk)
2352{
2353 struct page_frag *pfrag = sk_page_frag(sk);
2354
2355 if (!sk_page_frag_refill(sk, pfrag))
2356 return NULL;
2357
2358 *len = min_t(unsigned int, *len, pfrag->size - pfrag->offset);
2359
2360 memcpy(page_address(pfrag->page) + pfrag->offset,
2361 page_address(page) + *offset, *len);
2362 *offset = pfrag->offset;
2363 pfrag->offset += *len;
2364
2365 return pfrag->page;
2366}
2367
2368static bool spd_can_coalesce(const struct splice_pipe_desc *spd,
2369 struct page *page,
2370 unsigned int offset)
2371{
2372 return spd->nr_pages &&
2373 spd->pages[spd->nr_pages - 1] == page &&
2374 (spd->partial[spd->nr_pages - 1].offset +
2375 spd->partial[spd->nr_pages - 1].len == offset);
2376}
2377
2378/*
2379 * Fill page/offset/length into spd, if it can hold more pages.
2380 */
2381static bool spd_fill_page(struct splice_pipe_desc *spd,
2382 struct pipe_inode_info *pipe, struct page *page,
2383 unsigned int *len, unsigned int offset,
2384 bool linear,
2385 struct sock *sk)
2386{
2387 if (unlikely(spd->nr_pages == MAX_SKB_FRAGS))
2388 return true;
2389
2390 if (linear) {
2391 page = linear_to_page(page, len, &offset, sk);
2392 if (!page)
2393 return true;
2394 }
2395 if (spd_can_coalesce(spd, page, offset)) {
2396 spd->partial[spd->nr_pages - 1].len += *len;
2397 return false;
2398 }
2399 get_page(page);
2400 spd->pages[spd->nr_pages] = page;
2401 spd->partial[spd->nr_pages].len = *len;
2402 spd->partial[spd->nr_pages].offset = offset;
2403 spd->nr_pages++;
2404
2405 return false;
2406}
2407
2408static bool __splice_segment(struct page *page, unsigned int poff,
2409 unsigned int plen, unsigned int *off,
2410 unsigned int *len,
2411 struct splice_pipe_desc *spd, bool linear,
2412 struct sock *sk,
2413 struct pipe_inode_info *pipe)
2414{
2415 if (!*len)
2416 return true;
2417
2418 /* skip this segment if already processed */
2419 if (*off >= plen) {
2420 *off -= plen;
2421 return false;
2422 }
2423
2424 /* ignore any bits we already processed */
2425 poff += *off;
2426 plen -= *off;
2427 *off = 0;
2428
2429 do {
2430 unsigned int flen = min(*len, plen);
2431
2432 if (spd_fill_page(spd, pipe, page, &flen, poff,
2433 linear, sk))
2434 return true;
2435 poff += flen;
2436 plen -= flen;
2437 *len -= flen;
2438 } while (*len && plen);
2439
2440 return false;
2441}
2442
2443/*
2444 * Map linear and fragment data from the skb to spd. It reports true if the
2445 * pipe is full or if we already spliced the requested length.
2446 */
2447static bool __skb_splice_bits(struct sk_buff *skb, struct pipe_inode_info *pipe,
2448 unsigned int *offset, unsigned int *len,
2449 struct splice_pipe_desc *spd, struct sock *sk)
2450{
2451 int seg;
2452 struct sk_buff *iter;
2453
2454 /* map the linear part :
2455 * If skb->head_frag is set, this 'linear' part is backed by a
2456 * fragment, and if the head is not shared with any clones then
2457 * we can avoid a copy since we own the head portion of this page.
2458 */
2459 if (__splice_segment(virt_to_page(skb->data),
2460 (unsigned long) skb->data & (PAGE_SIZE - 1),
2461 skb_headlen(skb),
2462 offset, len, spd,
2463 skb_head_is_locked(skb),
2464 sk, pipe))
2465 return true;
2466
2467 /*
2468 * then map the fragments
2469 */
2470 for (seg = 0; seg < skb_shinfo(skb)->nr_frags; seg++) {
2471 const skb_frag_t *f = &skb_shinfo(skb)->frags[seg];
2472
2473 if (__splice_segment(skb_frag_page(f),
2474 skb_frag_off(f), skb_frag_size(f),
2475 offset, len, spd, false, sk, pipe))
2476 return true;
2477 }
2478
2479 skb_walk_frags(skb, iter) {
2480 if (*offset >= iter->len) {
2481 *offset -= iter->len;
2482 continue;
2483 }
2484 /* __skb_splice_bits() only fails if the output has no room
2485 * left, so no point in going over the frag_list for the error
2486 * case.
2487 */
2488 if (__skb_splice_bits(iter, pipe, offset, len, spd, sk))
2489 return true;
2490 }
2491
2492 return false;
2493}
2494
2495/*
2496 * Map data from the skb to a pipe. Should handle both the linear part,
2497 * the fragments, and the frag list.
2498 */
2499int skb_splice_bits(struct sk_buff *skb, struct sock *sk, unsigned int offset,
2500 struct pipe_inode_info *pipe, unsigned int tlen,
2501 unsigned int flags)
2502{
2503 struct partial_page partial[MAX_SKB_FRAGS];
2504 struct page *pages[MAX_SKB_FRAGS];
2505 struct splice_pipe_desc spd = {
2506 .pages = pages,
2507 .partial = partial,
2508 .nr_pages_max = MAX_SKB_FRAGS,
2509 .ops = &nosteal_pipe_buf_ops,
2510 .spd_release = sock_spd_release,
2511 };
2512 int ret = 0;
2513
2514 __skb_splice_bits(skb, pipe, &offset, &tlen, &spd, sk);
2515
2516 if (spd.nr_pages)
2517 ret = splice_to_pipe(pipe, &spd);
2518
2519 return ret;
2520}
2521EXPORT_SYMBOL_GPL(skb_splice_bits);
2522
2523static int sendmsg_unlocked(struct sock *sk, struct msghdr *msg,
2524 struct kvec *vec, size_t num, size_t size)
2525{
2526 struct socket *sock = sk->sk_socket;
2527
2528 if (!sock)
2529 return -EINVAL;
2530 return kernel_sendmsg(sock, msg, vec, num, size);
2531}
2532
2533static int sendpage_unlocked(struct sock *sk, struct page *page, int offset,
2534 size_t size, int flags)
2535{
2536 struct socket *sock = sk->sk_socket;
2537
2538 if (!sock)
2539 return -EINVAL;
2540 return kernel_sendpage(sock, page, offset, size, flags);
2541}
2542
2543typedef int (*sendmsg_func)(struct sock *sk, struct msghdr *msg,
2544 struct kvec *vec, size_t num, size_t size);
2545typedef int (*sendpage_func)(struct sock *sk, struct page *page, int offset,
2546 size_t size, int flags);
2547static int __skb_send_sock(struct sock *sk, struct sk_buff *skb, int offset,
2548 int len, sendmsg_func sendmsg, sendpage_func sendpage)
2549{
2550 unsigned int orig_len = len;
2551 struct sk_buff *head = skb;
2552 unsigned short fragidx;
2553 int slen, ret;
2554
2555do_frag_list:
2556
2557 /* Deal with head data */
2558 while (offset < skb_headlen(skb) && len) {
2559 struct kvec kv;
2560 struct msghdr msg;
2561
2562 slen = min_t(int, len, skb_headlen(skb) - offset);
2563 kv.iov_base = skb->data + offset;
2564 kv.iov_len = slen;
2565 memset(&msg, 0, sizeof(msg));
2566 msg.msg_flags = MSG_DONTWAIT;
2567
2568 ret = INDIRECT_CALL_2(sendmsg, kernel_sendmsg_locked,
2569 sendmsg_unlocked, sk, &msg, &kv, 1, slen);
2570 if (ret <= 0)
2571 goto error;
2572
2573 offset += ret;
2574 len -= ret;
2575 }
2576
2577 /* All the data was skb head? */
2578 if (!len)
2579 goto out;
2580
2581 /* Make offset relative to start of frags */
2582 offset -= skb_headlen(skb);
2583
2584 /* Find where we are in frag list */
2585 for (fragidx = 0; fragidx < skb_shinfo(skb)->nr_frags; fragidx++) {
2586 skb_frag_t *frag = &skb_shinfo(skb)->frags[fragidx];
2587
2588 if (offset < skb_frag_size(frag))
2589 break;
2590
2591 offset -= skb_frag_size(frag);
2592 }
2593
2594 for (; len && fragidx < skb_shinfo(skb)->nr_frags; fragidx++) {
2595 skb_frag_t *frag = &skb_shinfo(skb)->frags[fragidx];
2596
2597 slen = min_t(size_t, len, skb_frag_size(frag) - offset);
2598
2599 while (slen) {
2600 ret = INDIRECT_CALL_2(sendpage, kernel_sendpage_locked,
2601 sendpage_unlocked, sk,
2602 skb_frag_page(frag),
2603 skb_frag_off(frag) + offset,
2604 slen, MSG_DONTWAIT);
2605 if (ret <= 0)
2606 goto error;
2607
2608 len -= ret;
2609 offset += ret;
2610 slen -= ret;
2611 }
2612
2613 offset = 0;
2614 }
2615
2616 if (len) {
2617 /* Process any frag lists */
2618
2619 if (skb == head) {
2620 if (skb_has_frag_list(skb)) {
2621 skb = skb_shinfo(skb)->frag_list;
2622 goto do_frag_list;
2623 }
2624 } else if (skb->next) {
2625 skb = skb->next;
2626 goto do_frag_list;
2627 }
2628 }
2629
2630out:
2631 return orig_len - len;
2632
2633error:
2634 return orig_len == len ? ret : orig_len - len;
2635}
2636
2637/* Send skb data on a socket. Socket must be locked. */
2638int skb_send_sock_locked(struct sock *sk, struct sk_buff *skb, int offset,
2639 int len)
2640{
2641 return __skb_send_sock(sk, skb, offset, len, kernel_sendmsg_locked,
2642 kernel_sendpage_locked);
2643}
2644EXPORT_SYMBOL_GPL(skb_send_sock_locked);
2645
2646/* Send skb data on a socket. Socket must be unlocked. */
2647int skb_send_sock(struct sock *sk, struct sk_buff *skb, int offset, int len)
2648{
2649 return __skb_send_sock(sk, skb, offset, len, sendmsg_unlocked,
2650 sendpage_unlocked);
2651}
2652
2653/**
2654 * skb_store_bits - store bits from kernel buffer to skb
2655 * @skb: destination buffer
2656 * @offset: offset in destination
2657 * @from: source buffer
2658 * @len: number of bytes to copy
2659 *
2660 * Copy the specified number of bytes from the source buffer to the
2661 * destination skb. This function handles all the messy bits of
2662 * traversing fragment lists and such.
2663 */
2664
2665int skb_store_bits(struct sk_buff *skb, int offset, const void *from, int len)
2666{
2667 int start = skb_headlen(skb);
2668 struct sk_buff *frag_iter;
2669 int i, copy;
2670
2671 if (offset > (int)skb->len - len)
2672 goto fault;
2673
2674 if ((copy = start - offset) > 0) {
2675 if (copy > len)
2676 copy = len;
2677 skb_copy_to_linear_data_offset(skb, offset, from, copy);
2678 if ((len -= copy) == 0)
2679 return 0;
2680 offset += copy;
2681 from += copy;
2682 }
2683
2684 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
2685 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
2686 int end;
2687
2688 WARN_ON(start > offset + len);
2689
2690 end = start + skb_frag_size(frag);
2691 if ((copy = end - offset) > 0) {
2692 u32 p_off, p_len, copied;
2693 struct page *p;
2694 u8 *vaddr;
2695
2696 if (copy > len)
2697 copy = len;
2698
2699 skb_frag_foreach_page(frag,
2700 skb_frag_off(frag) + offset - start,
2701 copy, p, p_off, p_len, copied) {
2702 vaddr = kmap_atomic(p);
2703 memcpy(vaddr + p_off, from + copied, p_len);
2704 kunmap_atomic(vaddr);
2705 }
2706
2707 if ((len -= copy) == 0)
2708 return 0;
2709 offset += copy;
2710 from += copy;
2711 }
2712 start = end;
2713 }
2714
2715 skb_walk_frags(skb, frag_iter) {
2716 int end;
2717
2718 WARN_ON(start > offset + len);
2719
2720 end = start + frag_iter->len;
2721 if ((copy = end - offset) > 0) {
2722 if (copy > len)
2723 copy = len;
2724 if (skb_store_bits(frag_iter, offset - start,
2725 from, copy))
2726 goto fault;
2727 if ((len -= copy) == 0)
2728 return 0;
2729 offset += copy;
2730 from += copy;
2731 }
2732 start = end;
2733 }
2734 if (!len)
2735 return 0;
2736
2737fault:
2738 return -EFAULT;
2739}
2740EXPORT_SYMBOL(skb_store_bits);
2741
2742/* Checksum skb data. */
2743__wsum __skb_checksum(const struct sk_buff *skb, int offset, int len,
2744 __wsum csum, const struct skb_checksum_ops *ops)
2745{
2746 int start = skb_headlen(skb);
2747 int i, copy = start - offset;
2748 struct sk_buff *frag_iter;
2749 int pos = 0;
2750
2751 /* Checksum header. */
2752 if (copy > 0) {
2753 if (copy > len)
2754 copy = len;
2755 csum = INDIRECT_CALL_1(ops->update, csum_partial_ext,
2756 skb->data + offset, copy, csum);
2757 if ((len -= copy) == 0)
2758 return csum;
2759 offset += copy;
2760 pos = copy;
2761 }
2762
2763 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
2764 int end;
2765 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
2766
2767 WARN_ON(start > offset + len);
2768
2769 end = start + skb_frag_size(frag);
2770 if ((copy = end - offset) > 0) {
2771 u32 p_off, p_len, copied;
2772 struct page *p;
2773 __wsum csum2;
2774 u8 *vaddr;
2775
2776 if (copy > len)
2777 copy = len;
2778
2779 skb_frag_foreach_page(frag,
2780 skb_frag_off(frag) + offset - start,
2781 copy, p, p_off, p_len, copied) {
2782 vaddr = kmap_atomic(p);
2783 csum2 = INDIRECT_CALL_1(ops->update,
2784 csum_partial_ext,
2785 vaddr + p_off, p_len, 0);
2786 kunmap_atomic(vaddr);
2787 csum = INDIRECT_CALL_1(ops->combine,
2788 csum_block_add_ext, csum,
2789 csum2, pos, p_len);
2790 pos += p_len;
2791 }
2792
2793 if (!(len -= copy))
2794 return csum;
2795 offset += copy;
2796 }
2797 start = end;
2798 }
2799
2800 skb_walk_frags(skb, frag_iter) {
2801 int end;
2802
2803 WARN_ON(start > offset + len);
2804
2805 end = start + frag_iter->len;
2806 if ((copy = end - offset) > 0) {
2807 __wsum csum2;
2808 if (copy > len)
2809 copy = len;
2810 csum2 = __skb_checksum(frag_iter, offset - start,
2811 copy, 0, ops);
2812 csum = INDIRECT_CALL_1(ops->combine, csum_block_add_ext,
2813 csum, csum2, pos, copy);
2814 if ((len -= copy) == 0)
2815 return csum;
2816 offset += copy;
2817 pos += copy;
2818 }
2819 start = end;
2820 }
2821 BUG_ON(len);
2822
2823 return csum;
2824}
2825EXPORT_SYMBOL(__skb_checksum);
2826
2827__wsum skb_checksum(const struct sk_buff *skb, int offset,
2828 int len, __wsum csum)
2829{
2830 const struct skb_checksum_ops ops = {
2831 .update = csum_partial_ext,
2832 .combine = csum_block_add_ext,
2833 };
2834
2835 return __skb_checksum(skb, offset, len, csum, &ops);
2836}
2837EXPORT_SYMBOL(skb_checksum);
2838
2839/* Both of above in one bottle. */
2840
2841__wsum skb_copy_and_csum_bits(const struct sk_buff *skb, int offset,
2842 u8 *to, int len)
2843{
2844 int start = skb_headlen(skb);
2845 int i, copy = start - offset;
2846 struct sk_buff *frag_iter;
2847 int pos = 0;
2848 __wsum csum = 0;
2849
2850 /* Copy header. */
2851 if (copy > 0) {
2852 if (copy > len)
2853 copy = len;
2854 csum = csum_partial_copy_nocheck(skb->data + offset, to,
2855 copy);
2856 if ((len -= copy) == 0)
2857 return csum;
2858 offset += copy;
2859 to += copy;
2860 pos = copy;
2861 }
2862
2863 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
2864 int end;
2865
2866 WARN_ON(start > offset + len);
2867
2868 end = start + skb_frag_size(&skb_shinfo(skb)->frags[i]);
2869 if ((copy = end - offset) > 0) {
2870 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
2871 u32 p_off, p_len, copied;
2872 struct page *p;
2873 __wsum csum2;
2874 u8 *vaddr;
2875
2876 if (copy > len)
2877 copy = len;
2878
2879 skb_frag_foreach_page(frag,
2880 skb_frag_off(frag) + offset - start,
2881 copy, p, p_off, p_len, copied) {
2882 vaddr = kmap_atomic(p);
2883 csum2 = csum_partial_copy_nocheck(vaddr + p_off,
2884 to + copied,
2885 p_len);
2886 kunmap_atomic(vaddr);
2887 csum = csum_block_add(csum, csum2, pos);
2888 pos += p_len;
2889 }
2890
2891 if (!(len -= copy))
2892 return csum;
2893 offset += copy;
2894 to += copy;
2895 }
2896 start = end;
2897 }
2898
2899 skb_walk_frags(skb, frag_iter) {
2900 __wsum csum2;
2901 int end;
2902
2903 WARN_ON(start > offset + len);
2904
2905 end = start + frag_iter->len;
2906 if ((copy = end - offset) > 0) {
2907 if (copy > len)
2908 copy = len;
2909 csum2 = skb_copy_and_csum_bits(frag_iter,
2910 offset - start,
2911 to, copy);
2912 csum = csum_block_add(csum, csum2, pos);
2913 if ((len -= copy) == 0)
2914 return csum;
2915 offset += copy;
2916 to += copy;
2917 pos += copy;
2918 }
2919 start = end;
2920 }
2921 BUG_ON(len);
2922 return csum;
2923}
2924EXPORT_SYMBOL(skb_copy_and_csum_bits);
2925
2926__sum16 __skb_checksum_complete_head(struct sk_buff *skb, int len)
2927{
2928 __sum16 sum;
2929
2930 sum = csum_fold(skb_checksum(skb, 0, len, skb->csum));
2931 /* See comments in __skb_checksum_complete(). */
2932 if (likely(!sum)) {
2933 if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE) &&
2934 !skb->csum_complete_sw)
2935 netdev_rx_csum_fault(skb->dev, skb);
2936 }
2937 if (!skb_shared(skb))
2938 skb->csum_valid = !sum;
2939 return sum;
2940}
2941EXPORT_SYMBOL(__skb_checksum_complete_head);
2942
2943/* This function assumes skb->csum already holds pseudo header's checksum,
2944 * which has been changed from the hardware checksum, for example, by
2945 * __skb_checksum_validate_complete(). And, the original skb->csum must
2946 * have been validated unsuccessfully for CHECKSUM_COMPLETE case.
2947 *
2948 * It returns non-zero if the recomputed checksum is still invalid, otherwise
2949 * zero. The new checksum is stored back into skb->csum unless the skb is
2950 * shared.
2951 */
2952__sum16 __skb_checksum_complete(struct sk_buff *skb)
2953{
2954 __wsum csum;
2955 __sum16 sum;
2956
2957 csum = skb_checksum(skb, 0, skb->len, 0);
2958
2959 sum = csum_fold(csum_add(skb->csum, csum));
2960 /* This check is inverted, because we already knew the hardware
2961 * checksum is invalid before calling this function. So, if the
2962 * re-computed checksum is valid instead, then we have a mismatch
2963 * between the original skb->csum and skb_checksum(). This means either
2964 * the original hardware checksum is incorrect or we screw up skb->csum
2965 * when moving skb->data around.
2966 */
2967 if (likely(!sum)) {
2968 if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE) &&
2969 !skb->csum_complete_sw)
2970 netdev_rx_csum_fault(skb->dev, skb);
2971 }
2972
2973 if (!skb_shared(skb)) {
2974 /* Save full packet checksum */
2975 skb->csum = csum;
2976 skb->ip_summed = CHECKSUM_COMPLETE;
2977 skb->csum_complete_sw = 1;
2978 skb->csum_valid = !sum;
2979 }
2980
2981 return sum;
2982}
2983EXPORT_SYMBOL(__skb_checksum_complete);
2984
2985static __wsum warn_crc32c_csum_update(const void *buff, int len, __wsum sum)
2986{
2987 net_warn_ratelimited(
2988 "%s: attempt to compute crc32c without libcrc32c.ko\n",
2989 __func__);
2990 return 0;
2991}
2992
2993static __wsum warn_crc32c_csum_combine(__wsum csum, __wsum csum2,
2994 int offset, int len)
2995{
2996 net_warn_ratelimited(
2997 "%s: attempt to compute crc32c without libcrc32c.ko\n",
2998 __func__);
2999 return 0;
3000}
3001
3002static const struct skb_checksum_ops default_crc32c_ops = {
3003 .update = warn_crc32c_csum_update,
3004 .combine = warn_crc32c_csum_combine,
3005};
3006
3007const struct skb_checksum_ops *crc32c_csum_stub __read_mostly =
3008 &default_crc32c_ops;
3009EXPORT_SYMBOL(crc32c_csum_stub);
3010
3011 /**
3012 * skb_zerocopy_headlen - Calculate headroom needed for skb_zerocopy()
3013 * @from: source buffer
3014 *
3015 * Calculates the amount of linear headroom needed in the 'to' skb passed
3016 * into skb_zerocopy().
3017 */
3018unsigned int
3019skb_zerocopy_headlen(const struct sk_buff *from)
3020{
3021 unsigned int hlen = 0;
3022
3023 if (!from->head_frag ||
3024 skb_headlen(from) < L1_CACHE_BYTES ||
3025 skb_shinfo(from)->nr_frags >= MAX_SKB_FRAGS) {
3026 hlen = skb_headlen(from);
3027 if (!hlen)
3028 hlen = from->len;
3029 }
3030
3031 if (skb_has_frag_list(from))
3032 hlen = from->len;
3033
3034 return hlen;
3035}
3036EXPORT_SYMBOL_GPL(skb_zerocopy_headlen);
3037
3038/**
3039 * skb_zerocopy - Zero copy skb to skb
3040 * @to: destination buffer
3041 * @from: source buffer
3042 * @len: number of bytes to copy from source buffer
3043 * @hlen: size of linear headroom in destination buffer
3044 *
3045 * Copies up to `len` bytes from `from` to `to` by creating references
3046 * to the frags in the source buffer.
3047 *
3048 * The `hlen` as calculated by skb_zerocopy_headlen() specifies the
3049 * headroom in the `to` buffer.
3050 *
3051 * Return value:
3052 * 0: everything is OK
3053 * -ENOMEM: couldn't orphan frags of @from due to lack of memory
3054 * -EFAULT: skb_copy_bits() found some problem with skb geometry
3055 */
3056int
3057skb_zerocopy(struct sk_buff *to, struct sk_buff *from, int len, int hlen)
3058{
3059 int i, j = 0;
3060 int plen = 0; /* length of skb->head fragment */
3061 int ret;
3062 struct page *page;
3063 unsigned int offset;
3064
3065 BUG_ON(!from->head_frag && !hlen);
3066
3067 /* dont bother with small payloads */
3068 if (len <= skb_tailroom(to))
3069 return skb_copy_bits(from, 0, skb_put(to, len), len);
3070
3071 if (hlen) {
3072 ret = skb_copy_bits(from, 0, skb_put(to, hlen), hlen);
3073 if (unlikely(ret))
3074 return ret;
3075 len -= hlen;
3076 } else {
3077 plen = min_t(int, skb_headlen(from), len);
3078 if (plen) {
3079 page = virt_to_head_page(from->head);
3080 offset = from->data - (unsigned char *)page_address(page);
3081 __skb_fill_page_desc(to, 0, page, offset, plen);
3082 get_page(page);
3083 j = 1;
3084 len -= plen;
3085 }
3086 }
3087
3088 to->truesize += len + plen;
3089 to->len += len + plen;
3090 to->data_len += len + plen;
3091
3092 if (unlikely(skb_orphan_frags(from, GFP_ATOMIC))) {
3093 skb_tx_error(from);
3094 return -ENOMEM;
3095 }
3096 skb_zerocopy_clone(to, from, GFP_ATOMIC);
3097
3098 for (i = 0; i < skb_shinfo(from)->nr_frags; i++) {
3099 int size;
3100
3101 if (!len)
3102 break;
3103 skb_shinfo(to)->frags[j] = skb_shinfo(from)->frags[i];
3104 size = min_t(int, skb_frag_size(&skb_shinfo(to)->frags[j]),
3105 len);
3106 skb_frag_size_set(&skb_shinfo(to)->frags[j], size);
3107 len -= size;
3108 skb_frag_ref(to, j);
3109 j++;
3110 }
3111 skb_shinfo(to)->nr_frags = j;
3112
3113 return 0;
3114}
3115EXPORT_SYMBOL_GPL(skb_zerocopy);
3116
3117void skb_copy_and_csum_dev(const struct sk_buff *skb, u8 *to)
3118{
3119 __wsum csum;
3120 long csstart;
3121
3122 if (skb->ip_summed == CHECKSUM_PARTIAL)
3123 csstart = skb_checksum_start_offset(skb);
3124 else
3125 csstart = skb_headlen(skb);
3126
3127 BUG_ON(csstart > skb_headlen(skb));
3128
3129 skb_copy_from_linear_data(skb, to, csstart);
3130
3131 csum = 0;
3132 if (csstart != skb->len)
3133 csum = skb_copy_and_csum_bits(skb, csstart, to + csstart,
3134 skb->len - csstart);
3135
3136 if (skb->ip_summed == CHECKSUM_PARTIAL) {
3137 long csstuff = csstart + skb->csum_offset;
3138
3139 *((__sum16 *)(to + csstuff)) = csum_fold(csum);
3140 }
3141}
3142EXPORT_SYMBOL(skb_copy_and_csum_dev);
3143
3144/**
3145 * skb_dequeue - remove from the head of the queue
3146 * @list: list to dequeue from
3147 *
3148 * Remove the head of the list. The list lock is taken so the function
3149 * may be used safely with other locking list functions. The head item is
3150 * returned or %NULL if the list is empty.
3151 */
3152
3153struct sk_buff *skb_dequeue(struct sk_buff_head *list)
3154{
3155 unsigned long flags;
3156 struct sk_buff *result;
3157
3158 spin_lock_irqsave(&list->lock, flags);
3159 result = __skb_dequeue(list);
3160 spin_unlock_irqrestore(&list->lock, flags);
3161 return result;
3162}
3163EXPORT_SYMBOL(skb_dequeue);
3164
3165/**
3166 * skb_dequeue_tail - remove from the tail of the queue
3167 * @list: list to dequeue from
3168 *
3169 * Remove the tail of the list. The list lock is taken so the function
3170 * may be used safely with other locking list functions. The tail item is
3171 * returned or %NULL if the list is empty.
3172 */
3173struct sk_buff *skb_dequeue_tail(struct sk_buff_head *list)
3174{
3175 unsigned long flags;
3176 struct sk_buff *result;
3177
3178 spin_lock_irqsave(&list->lock, flags);
3179 result = __skb_dequeue_tail(list);
3180 spin_unlock_irqrestore(&list->lock, flags);
3181 return result;
3182}
3183EXPORT_SYMBOL(skb_dequeue_tail);
3184
3185/**
3186 * skb_queue_purge - empty a list
3187 * @list: list to empty
3188 *
3189 * Delete all buffers on an &sk_buff list. Each buffer is removed from
3190 * the list and one reference dropped. This function takes the list
3191 * lock and is atomic with respect to other list locking functions.
3192 */
3193void skb_queue_purge(struct sk_buff_head *list)
3194{
3195 struct sk_buff *skb;
3196 while ((skb = skb_dequeue(list)) != NULL)
3197 kfree_skb(skb);
3198}
3199EXPORT_SYMBOL(skb_queue_purge);
3200
3201/**
3202 * skb_rbtree_purge - empty a skb rbtree
3203 * @root: root of the rbtree to empty
3204 * Return value: the sum of truesizes of all purged skbs.
3205 *
3206 * Delete all buffers on an &sk_buff rbtree. Each buffer is removed from
3207 * the list and one reference dropped. This function does not take
3208 * any lock. Synchronization should be handled by the caller (e.g., TCP
3209 * out-of-order queue is protected by the socket lock).
3210 */
3211unsigned int skb_rbtree_purge(struct rb_root *root)
3212{
3213 struct rb_node *p = rb_first(root);
3214 unsigned int sum = 0;
3215
3216 while (p) {
3217 struct sk_buff *skb = rb_entry(p, struct sk_buff, rbnode);
3218
3219 p = rb_next(p);
3220 rb_erase(&skb->rbnode, root);
3221 sum += skb->truesize;
3222 kfree_skb(skb);
3223 }
3224 return sum;
3225}
3226
3227/**
3228 * skb_queue_head - queue a buffer at the list head
3229 * @list: list to use
3230 * @newsk: buffer to queue
3231 *
3232 * Queue a buffer at the start of the list. This function takes the
3233 * list lock and can be used safely with other locking &sk_buff functions
3234 * safely.
3235 *
3236 * A buffer cannot be placed on two lists at the same time.
3237 */
3238void skb_queue_head(struct sk_buff_head *list, struct sk_buff *newsk)
3239{
3240 unsigned long flags;
3241
3242 spin_lock_irqsave(&list->lock, flags);
3243 __skb_queue_head(list, newsk);
3244 spin_unlock_irqrestore(&list->lock, flags);
3245}
3246EXPORT_SYMBOL(skb_queue_head);
3247
3248/**
3249 * skb_queue_tail - queue a buffer at the list tail
3250 * @list: list to use
3251 * @newsk: buffer to queue
3252 *
3253 * Queue a buffer at the tail of the list. This function takes the
3254 * list lock and can be used safely with other locking &sk_buff functions
3255 * safely.
3256 *
3257 * A buffer cannot be placed on two lists at the same time.
3258 */
3259void skb_queue_tail(struct sk_buff_head *list, struct sk_buff *newsk)
3260{
3261 unsigned long flags;
3262
3263 spin_lock_irqsave(&list->lock, flags);
3264 __skb_queue_tail(list, newsk);
3265 spin_unlock_irqrestore(&list->lock, flags);
3266}
3267EXPORT_SYMBOL(skb_queue_tail);
3268
3269/**
3270 * skb_unlink - remove a buffer from a list
3271 * @skb: buffer to remove
3272 * @list: list to use
3273 *
3274 * Remove a packet from a list. The list locks are taken and this
3275 * function is atomic with respect to other list locked calls
3276 *
3277 * You must know what list the SKB is on.
3278 */
3279void skb_unlink(struct sk_buff *skb, struct sk_buff_head *list)
3280{
3281 unsigned long flags;
3282
3283 spin_lock_irqsave(&list->lock, flags);
3284 __skb_unlink(skb, list);
3285 spin_unlock_irqrestore(&list->lock, flags);
3286}
3287EXPORT_SYMBOL(skb_unlink);
3288
3289/**
3290 * skb_append - append a buffer
3291 * @old: buffer to insert after
3292 * @newsk: buffer to insert
3293 * @list: list to use
3294 *
3295 * Place a packet after a given packet in a list. The list locks are taken
3296 * and this function is atomic with respect to other list locked calls.
3297 * A buffer cannot be placed on two lists at the same time.
3298 */
3299void skb_append(struct sk_buff *old, struct sk_buff *newsk, struct sk_buff_head *list)
3300{
3301 unsigned long flags;
3302
3303 spin_lock_irqsave(&list->lock, flags);
3304 __skb_queue_after(list, old, newsk);
3305 spin_unlock_irqrestore(&list->lock, flags);
3306}
3307EXPORT_SYMBOL(skb_append);
3308
3309static inline void skb_split_inside_header(struct sk_buff *skb,
3310 struct sk_buff* skb1,
3311 const u32 len, const int pos)
3312{
3313 int i;
3314
3315 skb_copy_from_linear_data_offset(skb, len, skb_put(skb1, pos - len),
3316 pos - len);
3317 /* And move data appendix as is. */
3318 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
3319 skb_shinfo(skb1)->frags[i] = skb_shinfo(skb)->frags[i];
3320
3321 skb_shinfo(skb1)->nr_frags = skb_shinfo(skb)->nr_frags;
3322 skb_shinfo(skb)->nr_frags = 0;
3323 skb1->data_len = skb->data_len;
3324 skb1->len += skb1->data_len;
3325 skb->data_len = 0;
3326 skb->len = len;
3327 skb_set_tail_pointer(skb, len);
3328}
3329
3330static inline void skb_split_no_header(struct sk_buff *skb,
3331 struct sk_buff* skb1,
3332 const u32 len, int pos)
3333{
3334 int i, k = 0;
3335 const int nfrags = skb_shinfo(skb)->nr_frags;
3336
3337 skb_shinfo(skb)->nr_frags = 0;
3338 skb1->len = skb1->data_len = skb->len - len;
3339 skb->len = len;
3340 skb->data_len = len - pos;
3341
3342 for (i = 0; i < nfrags; i++) {
3343 int size = skb_frag_size(&skb_shinfo(skb)->frags[i]);
3344
3345 if (pos + size > len) {
3346 skb_shinfo(skb1)->frags[k] = skb_shinfo(skb)->frags[i];
3347
3348 if (pos < len) {
3349 /* Split frag.
3350 * We have two variants in this case:
3351 * 1. Move all the frag to the second
3352 * part, if it is possible. F.e.
3353 * this approach is mandatory for TUX,
3354 * where splitting is expensive.
3355 * 2. Split is accurately. We make this.
3356 */
3357 skb_frag_ref(skb, i);
3358 skb_frag_off_add(&skb_shinfo(skb1)->frags[0], len - pos);
3359 skb_frag_size_sub(&skb_shinfo(skb1)->frags[0], len - pos);
3360 skb_frag_size_set(&skb_shinfo(skb)->frags[i], len - pos);
3361 skb_shinfo(skb)->nr_frags++;
3362 }
3363 k++;
3364 } else
3365 skb_shinfo(skb)->nr_frags++;
3366 pos += size;
3367 }
3368 skb_shinfo(skb1)->nr_frags = k;
3369}
3370
3371/**
3372 * skb_split - Split fragmented skb to two parts at length len.
3373 * @skb: the buffer to split
3374 * @skb1: the buffer to receive the second part
3375 * @len: new length for skb
3376 */
3377void skb_split(struct sk_buff *skb, struct sk_buff *skb1, const u32 len)
3378{
3379 int pos = skb_headlen(skb);
3380
3381 skb_shinfo(skb1)->flags |= skb_shinfo(skb)->flags & SKBFL_SHARED_FRAG;
3382 skb_zerocopy_clone(skb1, skb, 0);
3383 if (len < pos) /* Split line is inside header. */
3384 skb_split_inside_header(skb, skb1, len, pos);
3385 else /* Second chunk has no header, nothing to copy. */
3386 skb_split_no_header(skb, skb1, len, pos);
3387}
3388EXPORT_SYMBOL(skb_split);
3389
3390/* Shifting from/to a cloned skb is a no-go.
3391 *
3392 * Caller cannot keep skb_shinfo related pointers past calling here!
3393 */
3394static int skb_prepare_for_shift(struct sk_buff *skb)
3395{
3396 int ret = 0;
3397
3398 if (skb_cloned(skb)) {
3399 /* Save and restore truesize: pskb_expand_head() may reallocate
3400 * memory where ksize(kmalloc(S)) != ksize(kmalloc(S)), but we
3401 * cannot change truesize at this point.
3402 */
3403 unsigned int save_truesize = skb->truesize;
3404
3405 ret = pskb_expand_head(skb, 0, 0, GFP_ATOMIC);
3406 skb->truesize = save_truesize;
3407 }
3408 return ret;
3409}
3410
3411/**
3412 * skb_shift - Shifts paged data partially from skb to another
3413 * @tgt: buffer into which tail data gets added
3414 * @skb: buffer from which the paged data comes from
3415 * @shiftlen: shift up to this many bytes
3416 *
3417 * Attempts to shift up to shiftlen worth of bytes, which may be less than
3418 * the length of the skb, from skb to tgt. Returns number bytes shifted.
3419 * It's up to caller to free skb if everything was shifted.
3420 *
3421 * If @tgt runs out of frags, the whole operation is aborted.
3422 *
3423 * Skb cannot include anything else but paged data while tgt is allowed
3424 * to have non-paged data as well.
3425 *
3426 * TODO: full sized shift could be optimized but that would need
3427 * specialized skb free'er to handle frags without up-to-date nr_frags.
3428 */
3429int skb_shift(struct sk_buff *tgt, struct sk_buff *skb, int shiftlen)
3430{
3431 int from, to, merge, todo;
3432 skb_frag_t *fragfrom, *fragto;
3433
3434 BUG_ON(shiftlen > skb->len);
3435
3436 if (skb_headlen(skb))
3437 return 0;
3438 if (skb_zcopy(tgt) || skb_zcopy(skb))
3439 return 0;
3440
3441 todo = shiftlen;
3442 from = 0;
3443 to = skb_shinfo(tgt)->nr_frags;
3444 fragfrom = &skb_shinfo(skb)->frags[from];
3445
3446 /* Actual merge is delayed until the point when we know we can
3447 * commit all, so that we don't have to undo partial changes
3448 */
3449 if (!to ||
3450 !skb_can_coalesce(tgt, to, skb_frag_page(fragfrom),
3451 skb_frag_off(fragfrom))) {
3452 merge = -1;
3453 } else {
3454 merge = to - 1;
3455
3456 todo -= skb_frag_size(fragfrom);
3457 if (todo < 0) {
3458 if (skb_prepare_for_shift(skb) ||
3459 skb_prepare_for_shift(tgt))
3460 return 0;
3461
3462 /* All previous frag pointers might be stale! */
3463 fragfrom = &skb_shinfo(skb)->frags[from];
3464 fragto = &skb_shinfo(tgt)->frags[merge];
3465
3466 skb_frag_size_add(fragto, shiftlen);
3467 skb_frag_size_sub(fragfrom, shiftlen);
3468 skb_frag_off_add(fragfrom, shiftlen);
3469
3470 goto onlymerged;
3471 }
3472
3473 from++;
3474 }
3475
3476 /* Skip full, not-fitting skb to avoid expensive operations */
3477 if ((shiftlen == skb->len) &&
3478 (skb_shinfo(skb)->nr_frags - from) > (MAX_SKB_FRAGS - to))
3479 return 0;
3480
3481 if (skb_prepare_for_shift(skb) || skb_prepare_for_shift(tgt))
3482 return 0;
3483
3484 while ((todo > 0) && (from < skb_shinfo(skb)->nr_frags)) {
3485 if (to == MAX_SKB_FRAGS)
3486 return 0;
3487
3488 fragfrom = &skb_shinfo(skb)->frags[from];
3489 fragto = &skb_shinfo(tgt)->frags[to];
3490
3491 if (todo >= skb_frag_size(fragfrom)) {
3492 *fragto = *fragfrom;
3493 todo -= skb_frag_size(fragfrom);
3494 from++;
3495 to++;
3496
3497 } else {
3498 __skb_frag_ref(fragfrom);
3499 skb_frag_page_copy(fragto, fragfrom);
3500 skb_frag_off_copy(fragto, fragfrom);
3501 skb_frag_size_set(fragto, todo);
3502
3503 skb_frag_off_add(fragfrom, todo);
3504 skb_frag_size_sub(fragfrom, todo);
3505 todo = 0;
3506
3507 to++;
3508 break;
3509 }
3510 }
3511
3512 /* Ready to "commit" this state change to tgt */
3513 skb_shinfo(tgt)->nr_frags = to;
3514
3515 if (merge >= 0) {
3516 fragfrom = &skb_shinfo(skb)->frags[0];
3517 fragto = &skb_shinfo(tgt)->frags[merge];
3518
3519 skb_frag_size_add(fragto, skb_frag_size(fragfrom));
3520 __skb_frag_unref(fragfrom, skb->pp_recycle);
3521 }
3522
3523 /* Reposition in the original skb */
3524 to = 0;
3525 while (from < skb_shinfo(skb)->nr_frags)
3526 skb_shinfo(skb)->frags[to++] = skb_shinfo(skb)->frags[from++];
3527 skb_shinfo(skb)->nr_frags = to;
3528
3529 BUG_ON(todo > 0 && !skb_shinfo(skb)->nr_frags);
3530
3531onlymerged:
3532 /* Most likely the tgt won't ever need its checksum anymore, skb on
3533 * the other hand might need it if it needs to be resent
3534 */
3535 tgt->ip_summed = CHECKSUM_PARTIAL;
3536 skb->ip_summed = CHECKSUM_PARTIAL;
3537
3538 /* Yak, is it really working this way? Some helper please? */
3539 skb->len -= shiftlen;
3540 skb->data_len -= shiftlen;
3541 skb->truesize -= shiftlen;
3542 tgt->len += shiftlen;
3543 tgt->data_len += shiftlen;
3544 tgt->truesize += shiftlen;
3545
3546 return shiftlen;
3547}
3548
3549/**
3550 * skb_prepare_seq_read - Prepare a sequential read of skb data
3551 * @skb: the buffer to read
3552 * @from: lower offset of data to be read
3553 * @to: upper offset of data to be read
3554 * @st: state variable
3555 *
3556 * Initializes the specified state variable. Must be called before
3557 * invoking skb_seq_read() for the first time.
3558 */
3559void skb_prepare_seq_read(struct sk_buff *skb, unsigned int from,
3560 unsigned int to, struct skb_seq_state *st)
3561{
3562 st->lower_offset = from;
3563 st->upper_offset = to;
3564 st->root_skb = st->cur_skb = skb;
3565 st->frag_idx = st->stepped_offset = 0;
3566 st->frag_data = NULL;
3567 st->frag_off = 0;
3568}
3569EXPORT_SYMBOL(skb_prepare_seq_read);
3570
3571/**
3572 * skb_seq_read - Sequentially read skb data
3573 * @consumed: number of bytes consumed by the caller so far
3574 * @data: destination pointer for data to be returned
3575 * @st: state variable
3576 *
3577 * Reads a block of skb data at @consumed relative to the
3578 * lower offset specified to skb_prepare_seq_read(). Assigns
3579 * the head of the data block to @data and returns the length
3580 * of the block or 0 if the end of the skb data or the upper
3581 * offset has been reached.
3582 *
3583 * The caller is not required to consume all of the data
3584 * returned, i.e. @consumed is typically set to the number
3585 * of bytes already consumed and the next call to
3586 * skb_seq_read() will return the remaining part of the block.
3587 *
3588 * Note 1: The size of each block of data returned can be arbitrary,
3589 * this limitation is the cost for zerocopy sequential
3590 * reads of potentially non linear data.
3591 *
3592 * Note 2: Fragment lists within fragments are not implemented
3593 * at the moment, state->root_skb could be replaced with
3594 * a stack for this purpose.
3595 */
3596unsigned int skb_seq_read(unsigned int consumed, const u8 **data,
3597 struct skb_seq_state *st)
3598{
3599 unsigned int block_limit, abs_offset = consumed + st->lower_offset;
3600 skb_frag_t *frag;
3601
3602 if (unlikely(abs_offset >= st->upper_offset)) {
3603 if (st->frag_data) {
3604 kunmap_atomic(st->frag_data);
3605 st->frag_data = NULL;
3606 }
3607 return 0;
3608 }
3609
3610next_skb:
3611 block_limit = skb_headlen(st->cur_skb) + st->stepped_offset;
3612
3613 if (abs_offset < block_limit && !st->frag_data) {
3614 *data = st->cur_skb->data + (abs_offset - st->stepped_offset);
3615 return block_limit - abs_offset;
3616 }
3617
3618 if (st->frag_idx == 0 && !st->frag_data)
3619 st->stepped_offset += skb_headlen(st->cur_skb);
3620
3621 while (st->frag_idx < skb_shinfo(st->cur_skb)->nr_frags) {
3622 unsigned int pg_idx, pg_off, pg_sz;
3623
3624 frag = &skb_shinfo(st->cur_skb)->frags[st->frag_idx];
3625
3626 pg_idx = 0;
3627 pg_off = skb_frag_off(frag);
3628 pg_sz = skb_frag_size(frag);
3629
3630 if (skb_frag_must_loop(skb_frag_page(frag))) {
3631 pg_idx = (pg_off + st->frag_off) >> PAGE_SHIFT;
3632 pg_off = offset_in_page(pg_off + st->frag_off);
3633 pg_sz = min_t(unsigned int, pg_sz - st->frag_off,
3634 PAGE_SIZE - pg_off);
3635 }
3636
3637 block_limit = pg_sz + st->stepped_offset;
3638 if (abs_offset < block_limit) {
3639 if (!st->frag_data)
3640 st->frag_data = kmap_atomic(skb_frag_page(frag) + pg_idx);
3641
3642 *data = (u8 *)st->frag_data + pg_off +
3643 (abs_offset - st->stepped_offset);
3644
3645 return block_limit - abs_offset;
3646 }
3647
3648 if (st->frag_data) {
3649 kunmap_atomic(st->frag_data);
3650 st->frag_data = NULL;
3651 }
3652
3653 st->stepped_offset += pg_sz;
3654 st->frag_off += pg_sz;
3655 if (st->frag_off == skb_frag_size(frag)) {
3656 st->frag_off = 0;
3657 st->frag_idx++;
3658 }
3659 }
3660
3661 if (st->frag_data) {
3662 kunmap_atomic(st->frag_data);
3663 st->frag_data = NULL;
3664 }
3665
3666 if (st->root_skb == st->cur_skb && skb_has_frag_list(st->root_skb)) {
3667 st->cur_skb = skb_shinfo(st->root_skb)->frag_list;
3668 st->frag_idx = 0;
3669 goto next_skb;
3670 } else if (st->cur_skb->next) {
3671 st->cur_skb = st->cur_skb->next;
3672 st->frag_idx = 0;
3673 goto next_skb;
3674 }
3675
3676 return 0;
3677}
3678EXPORT_SYMBOL(skb_seq_read);
3679
3680/**
3681 * skb_abort_seq_read - Abort a sequential read of skb data
3682 * @st: state variable
3683 *
3684 * Must be called if skb_seq_read() was not called until it
3685 * returned 0.
3686 */
3687void skb_abort_seq_read(struct skb_seq_state *st)
3688{
3689 if (st->frag_data)
3690 kunmap_atomic(st->frag_data);
3691}
3692EXPORT_SYMBOL(skb_abort_seq_read);
3693
3694#define TS_SKB_CB(state) ((struct skb_seq_state *) &((state)->cb))
3695
3696static unsigned int skb_ts_get_next_block(unsigned int offset, const u8 **text,
3697 struct ts_config *conf,
3698 struct ts_state *state)
3699{
3700 return skb_seq_read(offset, text, TS_SKB_CB(state));
3701}
3702
3703static void skb_ts_finish(struct ts_config *conf, struct ts_state *state)
3704{
3705 skb_abort_seq_read(TS_SKB_CB(state));
3706}
3707
3708/**
3709 * skb_find_text - Find a text pattern in skb data
3710 * @skb: the buffer to look in
3711 * @from: search offset
3712 * @to: search limit
3713 * @config: textsearch configuration
3714 *
3715 * Finds a pattern in the skb data according to the specified
3716 * textsearch configuration. Use textsearch_next() to retrieve
3717 * subsequent occurrences of the pattern. Returns the offset
3718 * to the first occurrence or UINT_MAX if no match was found.
3719 */
3720unsigned int skb_find_text(struct sk_buff *skb, unsigned int from,
3721 unsigned int to, struct ts_config *config)
3722{
3723 struct ts_state state;
3724 unsigned int ret;
3725
3726 BUILD_BUG_ON(sizeof(struct skb_seq_state) > sizeof(state.cb));
3727
3728 config->get_next_block = skb_ts_get_next_block;
3729 config->finish = skb_ts_finish;
3730
3731 skb_prepare_seq_read(skb, from, to, TS_SKB_CB(&state));
3732
3733 ret = textsearch_find(config, &state);
3734 return (ret <= to - from ? ret : UINT_MAX);
3735}
3736EXPORT_SYMBOL(skb_find_text);
3737
3738int skb_append_pagefrags(struct sk_buff *skb, struct page *page,
3739 int offset, size_t size)
3740{
3741 int i = skb_shinfo(skb)->nr_frags;
3742
3743 if (skb_can_coalesce(skb, i, page, offset)) {
3744 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], size);
3745 } else if (i < MAX_SKB_FRAGS) {
3746 get_page(page);
3747 skb_fill_page_desc(skb, i, page, offset, size);
3748 } else {
3749 return -EMSGSIZE;
3750 }
3751
3752 return 0;
3753}
3754EXPORT_SYMBOL_GPL(skb_append_pagefrags);
3755
3756/**
3757 * skb_pull_rcsum - pull skb and update receive checksum
3758 * @skb: buffer to update
3759 * @len: length of data pulled
3760 *
3761 * This function performs an skb_pull on the packet and updates
3762 * the CHECKSUM_COMPLETE checksum. It should be used on
3763 * receive path processing instead of skb_pull unless you know
3764 * that the checksum difference is zero (e.g., a valid IP header)
3765 * or you are setting ip_summed to CHECKSUM_NONE.
3766 */
3767void *skb_pull_rcsum(struct sk_buff *skb, unsigned int len)
3768{
3769 unsigned char *data = skb->data;
3770
3771 BUG_ON(len > skb->len);
3772 __skb_pull(skb, len);
3773 skb_postpull_rcsum(skb, data, len);
3774 return skb->data;
3775}
3776EXPORT_SYMBOL_GPL(skb_pull_rcsum);
3777
3778static inline skb_frag_t skb_head_frag_to_page_desc(struct sk_buff *frag_skb)
3779{
3780 skb_frag_t head_frag;
3781 struct page *page;
3782
3783 page = virt_to_head_page(frag_skb->head);
3784 __skb_frag_set_page(&head_frag, page);
3785 skb_frag_off_set(&head_frag, frag_skb->data -
3786 (unsigned char *)page_address(page));
3787 skb_frag_size_set(&head_frag, skb_headlen(frag_skb));
3788 return head_frag;
3789}
3790
3791struct sk_buff *skb_segment_list(struct sk_buff *skb,
3792 netdev_features_t features,
3793 unsigned int offset)
3794{
3795 struct sk_buff *list_skb = skb_shinfo(skb)->frag_list;
3796 unsigned int tnl_hlen = skb_tnl_header_len(skb);
3797 unsigned int delta_truesize = 0;
3798 unsigned int delta_len = 0;
3799 struct sk_buff *tail = NULL;
3800 struct sk_buff *nskb, *tmp;
3801 int err;
3802
3803 skb_push(skb, -skb_network_offset(skb) + offset);
3804
3805 skb_shinfo(skb)->frag_list = NULL;
3806
3807 do {
3808 nskb = list_skb;
3809 list_skb = list_skb->next;
3810
3811 err = 0;
3812 if (skb_shared(nskb)) {
3813 tmp = skb_clone(nskb, GFP_ATOMIC);
3814 if (tmp) {
3815 consume_skb(nskb);
3816 nskb = tmp;
3817 err = skb_unclone(nskb, GFP_ATOMIC);
3818 } else {
3819 err = -ENOMEM;
3820 }
3821 }
3822
3823 if (!tail)
3824 skb->next = nskb;
3825 else
3826 tail->next = nskb;
3827
3828 if (unlikely(err)) {
3829 nskb->next = list_skb;
3830 goto err_linearize;
3831 }
3832
3833 tail = nskb;
3834
3835 delta_len += nskb->len;
3836 delta_truesize += nskb->truesize;
3837
3838 skb_push(nskb, -skb_network_offset(nskb) + offset);
3839
3840 skb_release_head_state(nskb);
3841 __copy_skb_header(nskb, skb);
3842
3843 skb_headers_offset_update(nskb, skb_headroom(nskb) - skb_headroom(skb));
3844 skb_copy_from_linear_data_offset(skb, -tnl_hlen,
3845 nskb->data - tnl_hlen,
3846 offset + tnl_hlen);
3847
3848 if (skb_needs_linearize(nskb, features) &&
3849 __skb_linearize(nskb))
3850 goto err_linearize;
3851
3852 } while (list_skb);
3853
3854 skb->truesize = skb->truesize - delta_truesize;
3855 skb->data_len = skb->data_len - delta_len;
3856 skb->len = skb->len - delta_len;
3857
3858 skb_gso_reset(skb);
3859
3860 skb->prev = tail;
3861
3862 if (skb_needs_linearize(skb, features) &&
3863 __skb_linearize(skb))
3864 goto err_linearize;
3865
3866 skb_get(skb);
3867
3868 return skb;
3869
3870err_linearize:
3871 kfree_skb_list(skb->next);
3872 skb->next = NULL;
3873 return ERR_PTR(-ENOMEM);
3874}
3875EXPORT_SYMBOL_GPL(skb_segment_list);
3876
3877int skb_gro_receive_list(struct sk_buff *p, struct sk_buff *skb)
3878{
3879 if (unlikely(p->len + skb->len >= 65536))
3880 return -E2BIG;
3881
3882 if (NAPI_GRO_CB(p)->last == p)
3883 skb_shinfo(p)->frag_list = skb;
3884 else
3885 NAPI_GRO_CB(p)->last->next = skb;
3886
3887 skb_pull(skb, skb_gro_offset(skb));
3888
3889 NAPI_GRO_CB(p)->last = skb;
3890 NAPI_GRO_CB(p)->count++;
3891 p->data_len += skb->len;
3892 p->truesize += skb->truesize;
3893 p->len += skb->len;
3894
3895 NAPI_GRO_CB(skb)->same_flow = 1;
3896
3897 return 0;
3898}
3899
3900/**
3901 * skb_segment - Perform protocol segmentation on skb.
3902 * @head_skb: buffer to segment
3903 * @features: features for the output path (see dev->features)
3904 *
3905 * This function performs segmentation on the given skb. It returns
3906 * a pointer to the first in a list of new skbs for the segments.
3907 * In case of error it returns ERR_PTR(err).
3908 */
3909struct sk_buff *skb_segment(struct sk_buff *head_skb,
3910 netdev_features_t features)
3911{
3912 struct sk_buff *segs = NULL;
3913 struct sk_buff *tail = NULL;
3914 struct sk_buff *list_skb = skb_shinfo(head_skb)->frag_list;
3915 skb_frag_t *frag = skb_shinfo(head_skb)->frags;
3916 unsigned int mss = skb_shinfo(head_skb)->gso_size;
3917 unsigned int doffset = head_skb->data - skb_mac_header(head_skb);
3918 struct sk_buff *frag_skb = head_skb;
3919 unsigned int offset = doffset;
3920 unsigned int tnl_hlen = skb_tnl_header_len(head_skb);
3921 unsigned int partial_segs = 0;
3922 unsigned int headroom;
3923 unsigned int len = head_skb->len;
3924 __be16 proto;
3925 bool csum, sg;
3926 int nfrags = skb_shinfo(head_skb)->nr_frags;
3927 int err = -ENOMEM;
3928 int i = 0;
3929 int pos;
3930
3931 if (list_skb && !list_skb->head_frag && skb_headlen(list_skb) &&
3932 (skb_shinfo(head_skb)->gso_type & SKB_GSO_DODGY)) {
3933 /* gso_size is untrusted, and we have a frag_list with a linear
3934 * non head_frag head.
3935 *
3936 * (we assume checking the first list_skb member suffices;
3937 * i.e if either of the list_skb members have non head_frag
3938 * head, then the first one has too).
3939 *
3940 * If head_skb's headlen does not fit requested gso_size, it
3941 * means that the frag_list members do NOT terminate on exact
3942 * gso_size boundaries. Hence we cannot perform skb_frag_t page
3943 * sharing. Therefore we must fallback to copying the frag_list
3944 * skbs; we do so by disabling SG.
3945 */
3946 if (mss != GSO_BY_FRAGS && mss != skb_headlen(head_skb))
3947 features &= ~NETIF_F_SG;
3948 }
3949
3950 __skb_push(head_skb, doffset);
3951 proto = skb_network_protocol(head_skb, NULL);
3952 if (unlikely(!proto))
3953 return ERR_PTR(-EINVAL);
3954
3955 sg = !!(features & NETIF_F_SG);
3956 csum = !!can_checksum_protocol(features, proto);
3957
3958 if (sg && csum && (mss != GSO_BY_FRAGS)) {
3959 if (!(features & NETIF_F_GSO_PARTIAL)) {
3960 struct sk_buff *iter;
3961 unsigned int frag_len;
3962
3963 if (!list_skb ||
3964 !net_gso_ok(features, skb_shinfo(head_skb)->gso_type))
3965 goto normal;
3966
3967 /* If we get here then all the required
3968 * GSO features except frag_list are supported.
3969 * Try to split the SKB to multiple GSO SKBs
3970 * with no frag_list.
3971 * Currently we can do that only when the buffers don't
3972 * have a linear part and all the buffers except
3973 * the last are of the same length.
3974 */
3975 frag_len = list_skb->len;
3976 skb_walk_frags(head_skb, iter) {
3977 if (frag_len != iter->len && iter->next)
3978 goto normal;
3979 if (skb_headlen(iter) && !iter->head_frag)
3980 goto normal;
3981
3982 len -= iter->len;
3983 }
3984
3985 if (len != frag_len)
3986 goto normal;
3987 }
3988
3989 /* GSO partial only requires that we trim off any excess that
3990 * doesn't fit into an MSS sized block, so take care of that
3991 * now.
3992 */
3993 partial_segs = len / mss;
3994 if (partial_segs > 1)
3995 mss *= partial_segs;
3996 else
3997 partial_segs = 0;
3998 }
3999
4000normal:
4001 headroom = skb_headroom(head_skb);
4002 pos = skb_headlen(head_skb);
4003
4004 do {
4005 struct sk_buff *nskb;
4006 skb_frag_t *nskb_frag;
4007 int hsize;
4008 int size;
4009
4010 if (unlikely(mss == GSO_BY_FRAGS)) {
4011 len = list_skb->len;
4012 } else {
4013 len = head_skb->len - offset;
4014 if (len > mss)
4015 len = mss;
4016 }
4017
4018 hsize = skb_headlen(head_skb) - offset;
4019
4020 if (hsize <= 0 && i >= nfrags && skb_headlen(list_skb) &&
4021 (skb_headlen(list_skb) == len || sg)) {
4022 BUG_ON(skb_headlen(list_skb) > len);
4023
4024 i = 0;
4025 nfrags = skb_shinfo(list_skb)->nr_frags;
4026 frag = skb_shinfo(list_skb)->frags;
4027 frag_skb = list_skb;
4028 pos += skb_headlen(list_skb);
4029
4030 while (pos < offset + len) {
4031 BUG_ON(i >= nfrags);
4032
4033 size = skb_frag_size(frag);
4034 if (pos + size > offset + len)
4035 break;
4036
4037 i++;
4038 pos += size;
4039 frag++;
4040 }
4041
4042 nskb = skb_clone(list_skb, GFP_ATOMIC);
4043 list_skb = list_skb->next;
4044
4045 if (unlikely(!nskb))
4046 goto err;
4047
4048 if (unlikely(pskb_trim(nskb, len))) {
4049 kfree_skb(nskb);
4050 goto err;
4051 }
4052
4053 hsize = skb_end_offset(nskb);
4054 if (skb_cow_head(nskb, doffset + headroom)) {
4055 kfree_skb(nskb);
4056 goto err;
4057 }
4058
4059 nskb->truesize += skb_end_offset(nskb) - hsize;
4060 skb_release_head_state(nskb);
4061 __skb_push(nskb, doffset);
4062 } else {
4063 if (hsize < 0)
4064 hsize = 0;
4065 if (hsize > len || !sg)
4066 hsize = len;
4067
4068 nskb = __alloc_skb(hsize + doffset + headroom,
4069 GFP_ATOMIC, skb_alloc_rx_flag(head_skb),
4070 NUMA_NO_NODE);
4071
4072 if (unlikely(!nskb))
4073 goto err;
4074
4075 skb_reserve(nskb, headroom);
4076 __skb_put(nskb, doffset);
4077 }
4078
4079 if (segs)
4080 tail->next = nskb;
4081 else
4082 segs = nskb;
4083 tail = nskb;
4084
4085 __copy_skb_header(nskb, head_skb);
4086
4087 skb_headers_offset_update(nskb, skb_headroom(nskb) - headroom);
4088 skb_reset_mac_len(nskb);
4089
4090 skb_copy_from_linear_data_offset(head_skb, -tnl_hlen,
4091 nskb->data - tnl_hlen,
4092 doffset + tnl_hlen);
4093
4094 if (nskb->len == len + doffset)
4095 goto perform_csum_check;
4096
4097 if (!sg) {
4098 if (!csum) {
4099 if (!nskb->remcsum_offload)
4100 nskb->ip_summed = CHECKSUM_NONE;
4101 SKB_GSO_CB(nskb)->csum =
4102 skb_copy_and_csum_bits(head_skb, offset,
4103 skb_put(nskb,
4104 len),
4105 len);
4106 SKB_GSO_CB(nskb)->csum_start =
4107 skb_headroom(nskb) + doffset;
4108 } else {
4109 skb_copy_bits(head_skb, offset,
4110 skb_put(nskb, len),
4111 len);
4112 }
4113 continue;
4114 }
4115
4116 nskb_frag = skb_shinfo(nskb)->frags;
4117
4118 skb_copy_from_linear_data_offset(head_skb, offset,
4119 skb_put(nskb, hsize), hsize);
4120
4121 skb_shinfo(nskb)->flags |= skb_shinfo(head_skb)->flags &
4122 SKBFL_SHARED_FRAG;
4123
4124 if (skb_orphan_frags(frag_skb, GFP_ATOMIC) ||
4125 skb_zerocopy_clone(nskb, frag_skb, GFP_ATOMIC))
4126 goto err;
4127
4128 while (pos < offset + len) {
4129 if (i >= nfrags) {
4130 i = 0;
4131 nfrags = skb_shinfo(list_skb)->nr_frags;
4132 frag = skb_shinfo(list_skb)->frags;
4133 frag_skb = list_skb;
4134 if (!skb_headlen(list_skb)) {
4135 BUG_ON(!nfrags);
4136 } else {
4137 BUG_ON(!list_skb->head_frag);
4138
4139 /* to make room for head_frag. */
4140 i--;
4141 frag--;
4142 }
4143 if (skb_orphan_frags(frag_skb, GFP_ATOMIC) ||
4144 skb_zerocopy_clone(nskb, frag_skb,
4145 GFP_ATOMIC))
4146 goto err;
4147
4148 list_skb = list_skb->next;
4149 }
4150
4151 if (unlikely(skb_shinfo(nskb)->nr_frags >=
4152 MAX_SKB_FRAGS)) {
4153 net_warn_ratelimited(
4154 "skb_segment: too many frags: %u %u\n",
4155 pos, mss);
4156 err = -EINVAL;
4157 goto err;
4158 }
4159
4160 *nskb_frag = (i < 0) ? skb_head_frag_to_page_desc(frag_skb) : *frag;
4161 __skb_frag_ref(nskb_frag);
4162 size = skb_frag_size(nskb_frag);
4163
4164 if (pos < offset) {
4165 skb_frag_off_add(nskb_frag, offset - pos);
4166 skb_frag_size_sub(nskb_frag, offset - pos);
4167 }
4168
4169 skb_shinfo(nskb)->nr_frags++;
4170
4171 if (pos + size <= offset + len) {
4172 i++;
4173 frag++;
4174 pos += size;
4175 } else {
4176 skb_frag_size_sub(nskb_frag, pos + size - (offset + len));
4177 goto skip_fraglist;
4178 }
4179
4180 nskb_frag++;
4181 }
4182
4183skip_fraglist:
4184 nskb->data_len = len - hsize;
4185 nskb->len += nskb->data_len;
4186 nskb->truesize += nskb->data_len;
4187
4188perform_csum_check:
4189 if (!csum) {
4190 if (skb_has_shared_frag(nskb) &&
4191 __skb_linearize(nskb))
4192 goto err;
4193
4194 if (!nskb->remcsum_offload)
4195 nskb->ip_summed = CHECKSUM_NONE;
4196 SKB_GSO_CB(nskb)->csum =
4197 skb_checksum(nskb, doffset,
4198 nskb->len - doffset, 0);
4199 SKB_GSO_CB(nskb)->csum_start =
4200 skb_headroom(nskb) + doffset;
4201 }
4202 } while ((offset += len) < head_skb->len);
4203
4204 /* Some callers want to get the end of the list.
4205 * Put it in segs->prev to avoid walking the list.
4206 * (see validate_xmit_skb_list() for example)
4207 */
4208 segs->prev = tail;
4209
4210 if (partial_segs) {
4211 struct sk_buff *iter;
4212 int type = skb_shinfo(head_skb)->gso_type;
4213 unsigned short gso_size = skb_shinfo(head_skb)->gso_size;
4214
4215 /* Update type to add partial and then remove dodgy if set */
4216 type |= (features & NETIF_F_GSO_PARTIAL) / NETIF_F_GSO_PARTIAL * SKB_GSO_PARTIAL;
4217 type &= ~SKB_GSO_DODGY;
4218
4219 /* Update GSO info and prepare to start updating headers on
4220 * our way back down the stack of protocols.
4221 */
4222 for (iter = segs; iter; iter = iter->next) {
4223 skb_shinfo(iter)->gso_size = gso_size;
4224 skb_shinfo(iter)->gso_segs = partial_segs;
4225 skb_shinfo(iter)->gso_type = type;
4226 SKB_GSO_CB(iter)->data_offset = skb_headroom(iter) + doffset;
4227 }
4228
4229 if (tail->len - doffset <= gso_size)
4230 skb_shinfo(tail)->gso_size = 0;
4231 else if (tail != segs)
4232 skb_shinfo(tail)->gso_segs = DIV_ROUND_UP(tail->len - doffset, gso_size);
4233 }
4234
4235 /* Following permits correct backpressure, for protocols
4236 * using skb_set_owner_w().
4237 * Idea is to tranfert ownership from head_skb to last segment.
4238 */
4239 if (head_skb->destructor == sock_wfree) {
4240 swap(tail->truesize, head_skb->truesize);
4241 swap(tail->destructor, head_skb->destructor);
4242 swap(tail->sk, head_skb->sk);
4243 }
4244 return segs;
4245
4246err:
4247 kfree_skb_list(segs);
4248 return ERR_PTR(err);
4249}
4250EXPORT_SYMBOL_GPL(skb_segment);
4251
4252int skb_gro_receive(struct sk_buff *p, struct sk_buff *skb)
4253{
4254 struct skb_shared_info *pinfo, *skbinfo = skb_shinfo(skb);
4255 unsigned int offset = skb_gro_offset(skb);
4256 unsigned int headlen = skb_headlen(skb);
4257 unsigned int len = skb_gro_len(skb);
4258 unsigned int delta_truesize;
4259 struct sk_buff *lp;
4260
4261 if (unlikely(p->len + len >= 65536 || NAPI_GRO_CB(skb)->flush))
4262 return -E2BIG;
4263
4264 lp = NAPI_GRO_CB(p)->last;
4265 pinfo = skb_shinfo(lp);
4266
4267 if (headlen <= offset) {
4268 skb_frag_t *frag;
4269 skb_frag_t *frag2;
4270 int i = skbinfo->nr_frags;
4271 int nr_frags = pinfo->nr_frags + i;
4272
4273 if (nr_frags > MAX_SKB_FRAGS)
4274 goto merge;
4275
4276 offset -= headlen;
4277 pinfo->nr_frags = nr_frags;
4278 skbinfo->nr_frags = 0;
4279
4280 frag = pinfo->frags + nr_frags;
4281 frag2 = skbinfo->frags + i;
4282 do {
4283 *--frag = *--frag2;
4284 } while (--i);
4285
4286 skb_frag_off_add(frag, offset);
4287 skb_frag_size_sub(frag, offset);
4288
4289 /* all fragments truesize : remove (head size + sk_buff) */
4290 delta_truesize = skb->truesize -
4291 SKB_TRUESIZE(skb_end_offset(skb));
4292
4293 skb->truesize -= skb->data_len;
4294 skb->len -= skb->data_len;
4295 skb->data_len = 0;
4296
4297 NAPI_GRO_CB(skb)->free = NAPI_GRO_FREE;
4298 goto done;
4299 } else if (skb->head_frag) {
4300 int nr_frags = pinfo->nr_frags;
4301 skb_frag_t *frag = pinfo->frags + nr_frags;
4302 struct page *page = virt_to_head_page(skb->head);
4303 unsigned int first_size = headlen - offset;
4304 unsigned int first_offset;
4305
4306 if (nr_frags + 1 + skbinfo->nr_frags > MAX_SKB_FRAGS)
4307 goto merge;
4308
4309 first_offset = skb->data -
4310 (unsigned char *)page_address(page) +
4311 offset;
4312
4313 pinfo->nr_frags = nr_frags + 1 + skbinfo->nr_frags;
4314
4315 __skb_frag_set_page(frag, page);
4316 skb_frag_off_set(frag, first_offset);
4317 skb_frag_size_set(frag, first_size);
4318
4319 memcpy(frag + 1, skbinfo->frags, sizeof(*frag) * skbinfo->nr_frags);
4320 /* We dont need to clear skbinfo->nr_frags here */
4321
4322 delta_truesize = skb->truesize - SKB_DATA_ALIGN(sizeof(struct sk_buff));
4323 NAPI_GRO_CB(skb)->free = NAPI_GRO_FREE_STOLEN_HEAD;
4324 goto done;
4325 }
4326
4327merge:
4328 delta_truesize = skb->truesize;
4329 if (offset > headlen) {
4330 unsigned int eat = offset - headlen;
4331
4332 skb_frag_off_add(&skbinfo->frags[0], eat);
4333 skb_frag_size_sub(&skbinfo->frags[0], eat);
4334 skb->data_len -= eat;
4335 skb->len -= eat;
4336 offset = headlen;
4337 }
4338
4339 __skb_pull(skb, offset);
4340
4341 if (NAPI_GRO_CB(p)->last == p)
4342 skb_shinfo(p)->frag_list = skb;
4343 else
4344 NAPI_GRO_CB(p)->last->next = skb;
4345 NAPI_GRO_CB(p)->last = skb;
4346 __skb_header_release(skb);
4347 lp = p;
4348
4349done:
4350 NAPI_GRO_CB(p)->count++;
4351 p->data_len += len;
4352 p->truesize += delta_truesize;
4353 p->len += len;
4354 if (lp != p) {
4355 lp->data_len += len;
4356 lp->truesize += delta_truesize;
4357 lp->len += len;
4358 }
4359 NAPI_GRO_CB(skb)->same_flow = 1;
4360 return 0;
4361}
4362
4363#ifdef CONFIG_SKB_EXTENSIONS
4364#define SKB_EXT_ALIGN_VALUE 8
4365#define SKB_EXT_CHUNKSIZEOF(x) (ALIGN((sizeof(x)), SKB_EXT_ALIGN_VALUE) / SKB_EXT_ALIGN_VALUE)
4366
4367static const u8 skb_ext_type_len[] = {
4368#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
4369 [SKB_EXT_BRIDGE_NF] = SKB_EXT_CHUNKSIZEOF(struct nf_bridge_info),
4370#endif
4371#ifdef CONFIG_XFRM
4372 [SKB_EXT_SEC_PATH] = SKB_EXT_CHUNKSIZEOF(struct sec_path),
4373#endif
4374#if IS_ENABLED(CONFIG_NET_TC_SKB_EXT)
4375 [TC_SKB_EXT] = SKB_EXT_CHUNKSIZEOF(struct tc_skb_ext),
4376#endif
4377#if IS_ENABLED(CONFIG_MPTCP)
4378 [SKB_EXT_MPTCP] = SKB_EXT_CHUNKSIZEOF(struct mptcp_ext),
4379#endif
4380};
4381
4382static __always_inline unsigned int skb_ext_total_length(void)
4383{
4384 return SKB_EXT_CHUNKSIZEOF(struct skb_ext) +
4385#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
4386 skb_ext_type_len[SKB_EXT_BRIDGE_NF] +
4387#endif
4388#ifdef CONFIG_XFRM
4389 skb_ext_type_len[SKB_EXT_SEC_PATH] +
4390#endif
4391#if IS_ENABLED(CONFIG_NET_TC_SKB_EXT)
4392 skb_ext_type_len[TC_SKB_EXT] +
4393#endif
4394#if IS_ENABLED(CONFIG_MPTCP)
4395 skb_ext_type_len[SKB_EXT_MPTCP] +
4396#endif
4397 0;
4398}
4399
4400static void skb_extensions_init(void)
4401{
4402 BUILD_BUG_ON(SKB_EXT_NUM >= 8);
4403 BUILD_BUG_ON(skb_ext_total_length() > 255);
4404
4405 skbuff_ext_cache = kmem_cache_create("skbuff_ext_cache",
4406 SKB_EXT_ALIGN_VALUE * skb_ext_total_length(),
4407 0,
4408 SLAB_HWCACHE_ALIGN|SLAB_PANIC,
4409 NULL);
4410}
4411#else
4412static void skb_extensions_init(void) {}
4413#endif
4414
4415void __init skb_init(void)
4416{
4417 skbuff_head_cache = kmem_cache_create_usercopy("skbuff_head_cache",
4418 sizeof(struct sk_buff),
4419 0,
4420 SLAB_HWCACHE_ALIGN|SLAB_PANIC,
4421 offsetof(struct sk_buff, cb),
4422 sizeof_field(struct sk_buff, cb),
4423 NULL);
4424 skbuff_fclone_cache = kmem_cache_create("skbuff_fclone_cache",
4425 sizeof(struct sk_buff_fclones),
4426 0,
4427 SLAB_HWCACHE_ALIGN|SLAB_PANIC,
4428 NULL);
4429 skb_extensions_init();
4430}
4431
4432static int
4433__skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int len,
4434 unsigned int recursion_level)
4435{
4436 int start = skb_headlen(skb);
4437 int i, copy = start - offset;
4438 struct sk_buff *frag_iter;
4439 int elt = 0;
4440
4441 if (unlikely(recursion_level >= 24))
4442 return -EMSGSIZE;
4443
4444 if (copy > 0) {
4445 if (copy > len)
4446 copy = len;
4447 sg_set_buf(sg, skb->data + offset, copy);
4448 elt++;
4449 if ((len -= copy) == 0)
4450 return elt;
4451 offset += copy;
4452 }
4453
4454 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
4455 int end;
4456
4457 WARN_ON(start > offset + len);
4458
4459 end = start + skb_frag_size(&skb_shinfo(skb)->frags[i]);
4460 if ((copy = end - offset) > 0) {
4461 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
4462 if (unlikely(elt && sg_is_last(&sg[elt - 1])))
4463 return -EMSGSIZE;
4464
4465 if (copy > len)
4466 copy = len;
4467 sg_set_page(&sg[elt], skb_frag_page(frag), copy,
4468 skb_frag_off(frag) + offset - start);
4469 elt++;
4470 if (!(len -= copy))
4471 return elt;
4472 offset += copy;
4473 }
4474 start = end;
4475 }
4476
4477 skb_walk_frags(skb, frag_iter) {
4478 int end, ret;
4479
4480 WARN_ON(start > offset + len);
4481
4482 end = start + frag_iter->len;
4483 if ((copy = end - offset) > 0) {
4484 if (unlikely(elt && sg_is_last(&sg[elt - 1])))
4485 return -EMSGSIZE;
4486
4487 if (copy > len)
4488 copy = len;
4489 ret = __skb_to_sgvec(frag_iter, sg+elt, offset - start,
4490 copy, recursion_level + 1);
4491 if (unlikely(ret < 0))
4492 return ret;
4493 elt += ret;
4494 if ((len -= copy) == 0)
4495 return elt;
4496 offset += copy;
4497 }
4498 start = end;
4499 }
4500 BUG_ON(len);
4501 return elt;
4502}
4503
4504/**
4505 * skb_to_sgvec - Fill a scatter-gather list from a socket buffer
4506 * @skb: Socket buffer containing the buffers to be mapped
4507 * @sg: The scatter-gather list to map into
4508 * @offset: The offset into the buffer's contents to start mapping
4509 * @len: Length of buffer space to be mapped
4510 *
4511 * Fill the specified scatter-gather list with mappings/pointers into a
4512 * region of the buffer space attached to a socket buffer. Returns either
4513 * the number of scatterlist items used, or -EMSGSIZE if the contents
4514 * could not fit.
4515 */
4516int skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int len)
4517{
4518 int nsg = __skb_to_sgvec(skb, sg, offset, len, 0);
4519
4520 if (nsg <= 0)
4521 return nsg;
4522
4523 sg_mark_end(&sg[nsg - 1]);
4524
4525 return nsg;
4526}
4527EXPORT_SYMBOL_GPL(skb_to_sgvec);
4528
4529/* As compared with skb_to_sgvec, skb_to_sgvec_nomark only map skb to given
4530 * sglist without mark the sg which contain last skb data as the end.
4531 * So the caller can mannipulate sg list as will when padding new data after
4532 * the first call without calling sg_unmark_end to expend sg list.
4533 *
4534 * Scenario to use skb_to_sgvec_nomark:
4535 * 1. sg_init_table
4536 * 2. skb_to_sgvec_nomark(payload1)
4537 * 3. skb_to_sgvec_nomark(payload2)
4538 *
4539 * This is equivalent to:
4540 * 1. sg_init_table
4541 * 2. skb_to_sgvec(payload1)
4542 * 3. sg_unmark_end
4543 * 4. skb_to_sgvec(payload2)
4544 *
4545 * When mapping mutilple payload conditionally, skb_to_sgvec_nomark
4546 * is more preferable.
4547 */
4548int skb_to_sgvec_nomark(struct sk_buff *skb, struct scatterlist *sg,
4549 int offset, int len)
4550{
4551 return __skb_to_sgvec(skb, sg, offset, len, 0);
4552}
4553EXPORT_SYMBOL_GPL(skb_to_sgvec_nomark);
4554
4555
4556
4557/**
4558 * skb_cow_data - Check that a socket buffer's data buffers are writable
4559 * @skb: The socket buffer to check.
4560 * @tailbits: Amount of trailing space to be added
4561 * @trailer: Returned pointer to the skb where the @tailbits space begins
4562 *
4563 * Make sure that the data buffers attached to a socket buffer are
4564 * writable. If they are not, private copies are made of the data buffers
4565 * and the socket buffer is set to use these instead.
4566 *
4567 * If @tailbits is given, make sure that there is space to write @tailbits
4568 * bytes of data beyond current end of socket buffer. @trailer will be
4569 * set to point to the skb in which this space begins.
4570 *
4571 * The number of scatterlist elements required to completely map the
4572 * COW'd and extended socket buffer will be returned.
4573 */
4574int skb_cow_data(struct sk_buff *skb, int tailbits, struct sk_buff **trailer)
4575{
4576 int copyflag;
4577 int elt;
4578 struct sk_buff *skb1, **skb_p;
4579
4580 /* If skb is cloned or its head is paged, reallocate
4581 * head pulling out all the pages (pages are considered not writable
4582 * at the moment even if they are anonymous).
4583 */
4584 if ((skb_cloned(skb) || skb_shinfo(skb)->nr_frags) &&
4585 !__pskb_pull_tail(skb, __skb_pagelen(skb)))
4586 return -ENOMEM;
4587
4588 /* Easy case. Most of packets will go this way. */
4589 if (!skb_has_frag_list(skb)) {
4590 /* A little of trouble, not enough of space for trailer.
4591 * This should not happen, when stack is tuned to generate
4592 * good frames. OK, on miss we reallocate and reserve even more
4593 * space, 128 bytes is fair. */
4594
4595 if (skb_tailroom(skb) < tailbits &&
4596 pskb_expand_head(skb, 0, tailbits-skb_tailroom(skb)+128, GFP_ATOMIC))
4597 return -ENOMEM;
4598
4599 /* Voila! */
4600 *trailer = skb;
4601 return 1;
4602 }
4603
4604 /* Misery. We are in troubles, going to mincer fragments... */
4605
4606 elt = 1;
4607 skb_p = &skb_shinfo(skb)->frag_list;
4608 copyflag = 0;
4609
4610 while ((skb1 = *skb_p) != NULL) {
4611 int ntail = 0;
4612
4613 /* The fragment is partially pulled by someone,
4614 * this can happen on input. Copy it and everything
4615 * after it. */
4616
4617 if (skb_shared(skb1))
4618 copyflag = 1;
4619
4620 /* If the skb is the last, worry about trailer. */
4621
4622 if (skb1->next == NULL && tailbits) {
4623 if (skb_shinfo(skb1)->nr_frags ||
4624 skb_has_frag_list(skb1) ||
4625 skb_tailroom(skb1) < tailbits)
4626 ntail = tailbits + 128;
4627 }
4628
4629 if (copyflag ||
4630 skb_cloned(skb1) ||
4631 ntail ||
4632 skb_shinfo(skb1)->nr_frags ||
4633 skb_has_frag_list(skb1)) {
4634 struct sk_buff *skb2;
4635
4636 /* Fuck, we are miserable poor guys... */
4637 if (ntail == 0)
4638 skb2 = skb_copy(skb1, GFP_ATOMIC);
4639 else
4640 skb2 = skb_copy_expand(skb1,
4641 skb_headroom(skb1),
4642 ntail,
4643 GFP_ATOMIC);
4644 if (unlikely(skb2 == NULL))
4645 return -ENOMEM;
4646
4647 if (skb1->sk)
4648 skb_set_owner_w(skb2, skb1->sk);
4649
4650 /* Looking around. Are we still alive?
4651 * OK, link new skb, drop old one */
4652
4653 skb2->next = skb1->next;
4654 *skb_p = skb2;
4655 kfree_skb(skb1);
4656 skb1 = skb2;
4657 }
4658 elt++;
4659 *trailer = skb1;
4660 skb_p = &skb1->next;
4661 }
4662
4663 return elt;
4664}
4665EXPORT_SYMBOL_GPL(skb_cow_data);
4666
4667static void sock_rmem_free(struct sk_buff *skb)
4668{
4669 struct sock *sk = skb->sk;
4670
4671 atomic_sub(skb->truesize, &sk->sk_rmem_alloc);
4672}
4673
4674static void skb_set_err_queue(struct sk_buff *skb)
4675{
4676 /* pkt_type of skbs received on local sockets is never PACKET_OUTGOING.
4677 * So, it is safe to (mis)use it to mark skbs on the error queue.
4678 */
4679 skb->pkt_type = PACKET_OUTGOING;
4680 BUILD_BUG_ON(PACKET_OUTGOING == 0);
4681}
4682
4683/*
4684 * Note: We dont mem charge error packets (no sk_forward_alloc changes)
4685 */
4686int sock_queue_err_skb(struct sock *sk, struct sk_buff *skb)
4687{
4688 if (atomic_read(&sk->sk_rmem_alloc) + skb->truesize >=
4689 (unsigned int)READ_ONCE(sk->sk_rcvbuf))
4690 return -ENOMEM;
4691
4692 skb_orphan(skb);
4693 skb->sk = sk;
4694 skb->destructor = sock_rmem_free;
4695 atomic_add(skb->truesize, &sk->sk_rmem_alloc);
4696 skb_set_err_queue(skb);
4697
4698 /* before exiting rcu section, make sure dst is refcounted */
4699 skb_dst_force(skb);
4700
4701 skb_queue_tail(&sk->sk_error_queue, skb);
4702 if (!sock_flag(sk, SOCK_DEAD))
4703 sk_error_report(sk);
4704 return 0;
4705}
4706EXPORT_SYMBOL(sock_queue_err_skb);
4707
4708static bool is_icmp_err_skb(const struct sk_buff *skb)
4709{
4710 return skb && (SKB_EXT_ERR(skb)->ee.ee_origin == SO_EE_ORIGIN_ICMP ||
4711 SKB_EXT_ERR(skb)->ee.ee_origin == SO_EE_ORIGIN_ICMP6);
4712}
4713
4714struct sk_buff *sock_dequeue_err_skb(struct sock *sk)
4715{
4716 struct sk_buff_head *q = &sk->sk_error_queue;
4717 struct sk_buff *skb, *skb_next = NULL;
4718 bool icmp_next = false;
4719 unsigned long flags;
4720
4721 spin_lock_irqsave(&q->lock, flags);
4722 skb = __skb_dequeue(q);
4723 if (skb && (skb_next = skb_peek(q))) {
4724 icmp_next = is_icmp_err_skb(skb_next);
4725 if (icmp_next)
4726 sk->sk_err = SKB_EXT_ERR(skb_next)->ee.ee_errno;
4727 }
4728 spin_unlock_irqrestore(&q->lock, flags);
4729
4730 if (is_icmp_err_skb(skb) && !icmp_next)
4731 sk->sk_err = 0;
4732
4733 if (skb_next)
4734 sk_error_report(sk);
4735
4736 return skb;
4737}
4738EXPORT_SYMBOL(sock_dequeue_err_skb);
4739
4740/**
4741 * skb_clone_sk - create clone of skb, and take reference to socket
4742 * @skb: the skb to clone
4743 *
4744 * This function creates a clone of a buffer that holds a reference on
4745 * sk_refcnt. Buffers created via this function are meant to be
4746 * returned using sock_queue_err_skb, or free via kfree_skb.
4747 *
4748 * When passing buffers allocated with this function to sock_queue_err_skb
4749 * it is necessary to wrap the call with sock_hold/sock_put in order to
4750 * prevent the socket from being released prior to being enqueued on
4751 * the sk_error_queue.
4752 */
4753struct sk_buff *skb_clone_sk(struct sk_buff *skb)
4754{
4755 struct sock *sk = skb->sk;
4756 struct sk_buff *clone;
4757
4758 if (!sk || !refcount_inc_not_zero(&sk->sk_refcnt))
4759 return NULL;
4760
4761 clone = skb_clone(skb, GFP_ATOMIC);
4762 if (!clone) {
4763 sock_put(sk);
4764 return NULL;
4765 }
4766
4767 clone->sk = sk;
4768 clone->destructor = sock_efree;
4769
4770 return clone;
4771}
4772EXPORT_SYMBOL(skb_clone_sk);
4773
4774static void __skb_complete_tx_timestamp(struct sk_buff *skb,
4775 struct sock *sk,
4776 int tstype,
4777 bool opt_stats)
4778{
4779 struct sock_exterr_skb *serr;
4780 int err;
4781
4782 BUILD_BUG_ON(sizeof(struct sock_exterr_skb) > sizeof(skb->cb));
4783
4784 serr = SKB_EXT_ERR(skb);
4785 memset(serr, 0, sizeof(*serr));
4786 serr->ee.ee_errno = ENOMSG;
4787 serr->ee.ee_origin = SO_EE_ORIGIN_TIMESTAMPING;
4788 serr->ee.ee_info = tstype;
4789 serr->opt_stats = opt_stats;
4790 serr->header.h4.iif = skb->dev ? skb->dev->ifindex : 0;
4791 if (sk->sk_tsflags & SOF_TIMESTAMPING_OPT_ID) {
4792 serr->ee.ee_data = skb_shinfo(skb)->tskey;
4793 if (sk->sk_protocol == IPPROTO_TCP &&
4794 sk->sk_type == SOCK_STREAM)
4795 serr->ee.ee_data -= sk->sk_tskey;
4796 }
4797
4798 err = sock_queue_err_skb(sk, skb);
4799
4800 if (err)
4801 kfree_skb(skb);
4802}
4803
4804static bool skb_may_tx_timestamp(struct sock *sk, bool tsonly)
4805{
4806 bool ret;
4807
4808 if (likely(sysctl_tstamp_allow_data || tsonly))
4809 return true;
4810
4811 read_lock_bh(&sk->sk_callback_lock);
4812 ret = sk->sk_socket && sk->sk_socket->file &&
4813 file_ns_capable(sk->sk_socket->file, &init_user_ns, CAP_NET_RAW);
4814 read_unlock_bh(&sk->sk_callback_lock);
4815 return ret;
4816}
4817
4818void skb_complete_tx_timestamp(struct sk_buff *skb,
4819 struct skb_shared_hwtstamps *hwtstamps)
4820{
4821 struct sock *sk = skb->sk;
4822
4823 if (!skb_may_tx_timestamp(sk, false))
4824 goto err;
4825
4826 /* Take a reference to prevent skb_orphan() from freeing the socket,
4827 * but only if the socket refcount is not zero.
4828 */
4829 if (likely(refcount_inc_not_zero(&sk->sk_refcnt))) {
4830 *skb_hwtstamps(skb) = *hwtstamps;
4831 __skb_complete_tx_timestamp(skb, sk, SCM_TSTAMP_SND, false);
4832 sock_put(sk);
4833 return;
4834 }
4835
4836err:
4837 kfree_skb(skb);
4838}
4839EXPORT_SYMBOL_GPL(skb_complete_tx_timestamp);
4840
4841void __skb_tstamp_tx(struct sk_buff *orig_skb,
4842 const struct sk_buff *ack_skb,
4843 struct skb_shared_hwtstamps *hwtstamps,
4844 struct sock *sk, int tstype)
4845{
4846 struct sk_buff *skb;
4847 bool tsonly, opt_stats = false;
4848
4849 if (!sk)
4850 return;
4851
4852 if (!hwtstamps && !(sk->sk_tsflags & SOF_TIMESTAMPING_OPT_TX_SWHW) &&
4853 skb_shinfo(orig_skb)->tx_flags & SKBTX_IN_PROGRESS)
4854 return;
4855
4856 tsonly = sk->sk_tsflags & SOF_TIMESTAMPING_OPT_TSONLY;
4857 if (!skb_may_tx_timestamp(sk, tsonly))
4858 return;
4859
4860 if (tsonly) {
4861#ifdef CONFIG_INET
4862 if ((sk->sk_tsflags & SOF_TIMESTAMPING_OPT_STATS) &&
4863 sk->sk_protocol == IPPROTO_TCP &&
4864 sk->sk_type == SOCK_STREAM) {
4865 skb = tcp_get_timestamping_opt_stats(sk, orig_skb,
4866 ack_skb);
4867 opt_stats = true;
4868 } else
4869#endif
4870 skb = alloc_skb(0, GFP_ATOMIC);
4871 } else {
4872 skb = skb_clone(orig_skb, GFP_ATOMIC);
4873 }
4874 if (!skb)
4875 return;
4876
4877 if (tsonly) {
4878 skb_shinfo(skb)->tx_flags |= skb_shinfo(orig_skb)->tx_flags &
4879 SKBTX_ANY_TSTAMP;
4880 skb_shinfo(skb)->tskey = skb_shinfo(orig_skb)->tskey;
4881 }
4882
4883 if (hwtstamps)
4884 *skb_hwtstamps(skb) = *hwtstamps;
4885 else
4886 skb->tstamp = ktime_get_real();
4887
4888 __skb_complete_tx_timestamp(skb, sk, tstype, opt_stats);
4889}
4890EXPORT_SYMBOL_GPL(__skb_tstamp_tx);
4891
4892void skb_tstamp_tx(struct sk_buff *orig_skb,
4893 struct skb_shared_hwtstamps *hwtstamps)
4894{
4895 return __skb_tstamp_tx(orig_skb, NULL, hwtstamps, orig_skb->sk,
4896 SCM_TSTAMP_SND);
4897}
4898EXPORT_SYMBOL_GPL(skb_tstamp_tx);
4899
4900void skb_complete_wifi_ack(struct sk_buff *skb, bool acked)
4901{
4902 struct sock *sk = skb->sk;
4903 struct sock_exterr_skb *serr;
4904 int err = 1;
4905
4906 skb->wifi_acked_valid = 1;
4907 skb->wifi_acked = acked;
4908
4909 serr = SKB_EXT_ERR(skb);
4910 memset(serr, 0, sizeof(*serr));
4911 serr->ee.ee_errno = ENOMSG;
4912 serr->ee.ee_origin = SO_EE_ORIGIN_TXSTATUS;
4913
4914 /* Take a reference to prevent skb_orphan() from freeing the socket,
4915 * but only if the socket refcount is not zero.
4916 */
4917 if (likely(refcount_inc_not_zero(&sk->sk_refcnt))) {
4918 err = sock_queue_err_skb(sk, skb);
4919 sock_put(sk);
4920 }
4921 if (err)
4922 kfree_skb(skb);
4923}
4924EXPORT_SYMBOL_GPL(skb_complete_wifi_ack);
4925
4926/**
4927 * skb_partial_csum_set - set up and verify partial csum values for packet
4928 * @skb: the skb to set
4929 * @start: the number of bytes after skb->data to start checksumming.
4930 * @off: the offset from start to place the checksum.
4931 *
4932 * For untrusted partially-checksummed packets, we need to make sure the values
4933 * for skb->csum_start and skb->csum_offset are valid so we don't oops.
4934 *
4935 * This function checks and sets those values and skb->ip_summed: if this
4936 * returns false you should drop the packet.
4937 */
4938bool skb_partial_csum_set(struct sk_buff *skb, u16 start, u16 off)
4939{
4940 u32 csum_end = (u32)start + (u32)off + sizeof(__sum16);
4941 u32 csum_start = skb_headroom(skb) + (u32)start;
4942
4943 if (unlikely(csum_start > U16_MAX || csum_end > skb_headlen(skb))) {
4944 net_warn_ratelimited("bad partial csum: csum=%u/%u headroom=%u headlen=%u\n",
4945 start, off, skb_headroom(skb), skb_headlen(skb));
4946 return false;
4947 }
4948 skb->ip_summed = CHECKSUM_PARTIAL;
4949 skb->csum_start = csum_start;
4950 skb->csum_offset = off;
4951 skb_set_transport_header(skb, start);
4952 return true;
4953}
4954EXPORT_SYMBOL_GPL(skb_partial_csum_set);
4955
4956static int skb_maybe_pull_tail(struct sk_buff *skb, unsigned int len,
4957 unsigned int max)
4958{
4959 if (skb_headlen(skb) >= len)
4960 return 0;
4961
4962 /* If we need to pullup then pullup to the max, so we
4963 * won't need to do it again.
4964 */
4965 if (max > skb->len)
4966 max = skb->len;
4967
4968 if (__pskb_pull_tail(skb, max - skb_headlen(skb)) == NULL)
4969 return -ENOMEM;
4970
4971 if (skb_headlen(skb) < len)
4972 return -EPROTO;
4973
4974 return 0;
4975}
4976
4977#define MAX_TCP_HDR_LEN (15 * 4)
4978
4979static __sum16 *skb_checksum_setup_ip(struct sk_buff *skb,
4980 typeof(IPPROTO_IP) proto,
4981 unsigned int off)
4982{
4983 int err;
4984
4985 switch (proto) {
4986 case IPPROTO_TCP:
4987 err = skb_maybe_pull_tail(skb, off + sizeof(struct tcphdr),
4988 off + MAX_TCP_HDR_LEN);
4989 if (!err && !skb_partial_csum_set(skb, off,
4990 offsetof(struct tcphdr,
4991 check)))
4992 err = -EPROTO;
4993 return err ? ERR_PTR(err) : &tcp_hdr(skb)->check;
4994
4995 case IPPROTO_UDP:
4996 err = skb_maybe_pull_tail(skb, off + sizeof(struct udphdr),
4997 off + sizeof(struct udphdr));
4998 if (!err && !skb_partial_csum_set(skb, off,
4999 offsetof(struct udphdr,
5000 check)))
5001 err = -EPROTO;
5002 return err ? ERR_PTR(err) : &udp_hdr(skb)->check;
5003 }
5004
5005 return ERR_PTR(-EPROTO);
5006}
5007
5008/* This value should be large enough to cover a tagged ethernet header plus
5009 * maximally sized IP and TCP or UDP headers.
5010 */
5011#define MAX_IP_HDR_LEN 128
5012
5013static int skb_checksum_setup_ipv4(struct sk_buff *skb, bool recalculate)
5014{
5015 unsigned int off;
5016 bool fragment;
5017 __sum16 *csum;
5018 int err;
5019
5020 fragment = false;
5021
5022 err = skb_maybe_pull_tail(skb,
5023 sizeof(struct iphdr),
5024 MAX_IP_HDR_LEN);
5025 if (err < 0)
5026 goto out;
5027
5028 if (ip_is_fragment(ip_hdr(skb)))
5029 fragment = true;
5030
5031 off = ip_hdrlen(skb);
5032
5033 err = -EPROTO;
5034
5035 if (fragment)
5036 goto out;
5037
5038 csum = skb_checksum_setup_ip(skb, ip_hdr(skb)->protocol, off);
5039 if (IS_ERR(csum))
5040 return PTR_ERR(csum);
5041
5042 if (recalculate)
5043 *csum = ~csum_tcpudp_magic(ip_hdr(skb)->saddr,
5044 ip_hdr(skb)->daddr,
5045 skb->len - off,
5046 ip_hdr(skb)->protocol, 0);
5047 err = 0;
5048
5049out:
5050 return err;
5051}
5052
5053/* This value should be large enough to cover a tagged ethernet header plus
5054 * an IPv6 header, all options, and a maximal TCP or UDP header.
5055 */
5056#define MAX_IPV6_HDR_LEN 256
5057
5058#define OPT_HDR(type, skb, off) \
5059 (type *)(skb_network_header(skb) + (off))
5060
5061static int skb_checksum_setup_ipv6(struct sk_buff *skb, bool recalculate)
5062{
5063 int err;
5064 u8 nexthdr;
5065 unsigned int off;
5066 unsigned int len;
5067 bool fragment;
5068 bool done;
5069 __sum16 *csum;
5070
5071 fragment = false;
5072 done = false;
5073
5074 off = sizeof(struct ipv6hdr);
5075
5076 err = skb_maybe_pull_tail(skb, off, MAX_IPV6_HDR_LEN);
5077 if (err < 0)
5078 goto out;
5079
5080 nexthdr = ipv6_hdr(skb)->nexthdr;
5081
5082 len = sizeof(struct ipv6hdr) + ntohs(ipv6_hdr(skb)->payload_len);
5083 while (off <= len && !done) {
5084 switch (nexthdr) {
5085 case IPPROTO_DSTOPTS:
5086 case IPPROTO_HOPOPTS:
5087 case IPPROTO_ROUTING: {
5088 struct ipv6_opt_hdr *hp;
5089
5090 err = skb_maybe_pull_tail(skb,
5091 off +
5092 sizeof(struct ipv6_opt_hdr),
5093 MAX_IPV6_HDR_LEN);
5094 if (err < 0)
5095 goto out;
5096
5097 hp = OPT_HDR(struct ipv6_opt_hdr, skb, off);
5098 nexthdr = hp->nexthdr;
5099 off += ipv6_optlen(hp);
5100 break;
5101 }
5102 case IPPROTO_AH: {
5103 struct ip_auth_hdr *hp;
5104
5105 err = skb_maybe_pull_tail(skb,
5106 off +
5107 sizeof(struct ip_auth_hdr),
5108 MAX_IPV6_HDR_LEN);
5109 if (err < 0)
5110 goto out;
5111
5112 hp = OPT_HDR(struct ip_auth_hdr, skb, off);
5113 nexthdr = hp->nexthdr;
5114 off += ipv6_authlen(hp);
5115 break;
5116 }
5117 case IPPROTO_FRAGMENT: {
5118 struct frag_hdr *hp;
5119
5120 err = skb_maybe_pull_tail(skb,
5121 off +
5122 sizeof(struct frag_hdr),
5123 MAX_IPV6_HDR_LEN);
5124 if (err < 0)
5125 goto out;
5126
5127 hp = OPT_HDR(struct frag_hdr, skb, off);
5128
5129 if (hp->frag_off & htons(IP6_OFFSET | IP6_MF))
5130 fragment = true;
5131
5132 nexthdr = hp->nexthdr;
5133 off += sizeof(struct frag_hdr);
5134 break;
5135 }
5136 default:
5137 done = true;
5138 break;
5139 }
5140 }
5141
5142 err = -EPROTO;
5143
5144 if (!done || fragment)
5145 goto out;
5146
5147 csum = skb_checksum_setup_ip(skb, nexthdr, off);
5148 if (IS_ERR(csum))
5149 return PTR_ERR(csum);
5150
5151 if (recalculate)
5152 *csum = ~csum_ipv6_magic(&ipv6_hdr(skb)->saddr,
5153 &ipv6_hdr(skb)->daddr,
5154 skb->len - off, nexthdr, 0);
5155 err = 0;
5156
5157out:
5158 return err;
5159}
5160
5161/**
5162 * skb_checksum_setup - set up partial checksum offset
5163 * @skb: the skb to set up
5164 * @recalculate: if true the pseudo-header checksum will be recalculated
5165 */
5166int skb_checksum_setup(struct sk_buff *skb, bool recalculate)
5167{
5168 int err;
5169
5170 switch (skb->protocol) {
5171 case htons(ETH_P_IP):
5172 err = skb_checksum_setup_ipv4(skb, recalculate);
5173 break;
5174
5175 case htons(ETH_P_IPV6):
5176 err = skb_checksum_setup_ipv6(skb, recalculate);
5177 break;
5178
5179 default:
5180 err = -EPROTO;
5181 break;
5182 }
5183
5184 return err;
5185}
5186EXPORT_SYMBOL(skb_checksum_setup);
5187
5188/**
5189 * skb_checksum_maybe_trim - maybe trims the given skb
5190 * @skb: the skb to check
5191 * @transport_len: the data length beyond the network header
5192 *
5193 * Checks whether the given skb has data beyond the given transport length.
5194 * If so, returns a cloned skb trimmed to this transport length.
5195 * Otherwise returns the provided skb. Returns NULL in error cases
5196 * (e.g. transport_len exceeds skb length or out-of-memory).
5197 *
5198 * Caller needs to set the skb transport header and free any returned skb if it
5199 * differs from the provided skb.
5200 */
5201static struct sk_buff *skb_checksum_maybe_trim(struct sk_buff *skb,
5202 unsigned int transport_len)
5203{
5204 struct sk_buff *skb_chk;
5205 unsigned int len = skb_transport_offset(skb) + transport_len;
5206 int ret;
5207
5208 if (skb->len < len)
5209 return NULL;
5210 else if (skb->len == len)
5211 return skb;
5212
5213 skb_chk = skb_clone(skb, GFP_ATOMIC);
5214 if (!skb_chk)
5215 return NULL;
5216
5217 ret = pskb_trim_rcsum(skb_chk, len);
5218 if (ret) {
5219 kfree_skb(skb_chk);
5220 return NULL;
5221 }
5222
5223 return skb_chk;
5224}
5225
5226/**
5227 * skb_checksum_trimmed - validate checksum of an skb
5228 * @skb: the skb to check
5229 * @transport_len: the data length beyond the network header
5230 * @skb_chkf: checksum function to use
5231 *
5232 * Applies the given checksum function skb_chkf to the provided skb.
5233 * Returns a checked and maybe trimmed skb. Returns NULL on error.
5234 *
5235 * If the skb has data beyond the given transport length, then a
5236 * trimmed & cloned skb is checked and returned.
5237 *
5238 * Caller needs to set the skb transport header and free any returned skb if it
5239 * differs from the provided skb.
5240 */
5241struct sk_buff *skb_checksum_trimmed(struct sk_buff *skb,
5242 unsigned int transport_len,
5243 __sum16(*skb_chkf)(struct sk_buff *skb))
5244{
5245 struct sk_buff *skb_chk;
5246 unsigned int offset = skb_transport_offset(skb);
5247 __sum16 ret;
5248
5249 skb_chk = skb_checksum_maybe_trim(skb, transport_len);
5250 if (!skb_chk)
5251 goto err;
5252
5253 if (!pskb_may_pull(skb_chk, offset))
5254 goto err;
5255
5256 skb_pull_rcsum(skb_chk, offset);
5257 ret = skb_chkf(skb_chk);
5258 skb_push_rcsum(skb_chk, offset);
5259
5260 if (ret)
5261 goto err;
5262
5263 return skb_chk;
5264
5265err:
5266 if (skb_chk && skb_chk != skb)
5267 kfree_skb(skb_chk);
5268
5269 return NULL;
5270
5271}
5272EXPORT_SYMBOL(skb_checksum_trimmed);
5273
5274void __skb_warn_lro_forwarding(const struct sk_buff *skb)
5275{
5276 net_warn_ratelimited("%s: received packets cannot be forwarded while LRO is enabled\n",
5277 skb->dev->name);
5278}
5279EXPORT_SYMBOL(__skb_warn_lro_forwarding);
5280
5281void kfree_skb_partial(struct sk_buff *skb, bool head_stolen)
5282{
5283 if (head_stolen) {
5284 skb_release_head_state(skb);
5285 kmem_cache_free(skbuff_head_cache, skb);
5286 } else {
5287 __kfree_skb(skb);
5288 }
5289}
5290EXPORT_SYMBOL(kfree_skb_partial);
5291
5292/**
5293 * skb_try_coalesce - try to merge skb to prior one
5294 * @to: prior buffer
5295 * @from: buffer to add
5296 * @fragstolen: pointer to boolean
5297 * @delta_truesize: how much more was allocated than was requested
5298 */
5299bool skb_try_coalesce(struct sk_buff *to, struct sk_buff *from,
5300 bool *fragstolen, int *delta_truesize)
5301{
5302 struct skb_shared_info *to_shinfo, *from_shinfo;
5303 int i, delta, len = from->len;
5304
5305 *fragstolen = false;
5306
5307 if (skb_cloned(to))
5308 return false;
5309
5310 /* The page pool signature of struct page will eventually figure out
5311 * which pages can be recycled or not but for now let's prohibit slab
5312 * allocated and page_pool allocated SKBs from being coalesced.
5313 */
5314 if (to->pp_recycle != from->pp_recycle)
5315 return false;
5316
5317 if (len <= skb_tailroom(to)) {
5318 if (len)
5319 BUG_ON(skb_copy_bits(from, 0, skb_put(to, len), len));
5320 *delta_truesize = 0;
5321 return true;
5322 }
5323
5324 to_shinfo = skb_shinfo(to);
5325 from_shinfo = skb_shinfo(from);
5326 if (to_shinfo->frag_list || from_shinfo->frag_list)
5327 return false;
5328 if (skb_zcopy(to) || skb_zcopy(from))
5329 return false;
5330
5331 if (skb_headlen(from) != 0) {
5332 struct page *page;
5333 unsigned int offset;
5334
5335 if (to_shinfo->nr_frags +
5336 from_shinfo->nr_frags >= MAX_SKB_FRAGS)
5337 return false;
5338
5339 if (skb_head_is_locked(from))
5340 return false;
5341
5342 delta = from->truesize - SKB_DATA_ALIGN(sizeof(struct sk_buff));
5343
5344 page = virt_to_head_page(from->head);
5345 offset = from->data - (unsigned char *)page_address(page);
5346
5347 skb_fill_page_desc(to, to_shinfo->nr_frags,
5348 page, offset, skb_headlen(from));
5349 *fragstolen = true;
5350 } else {
5351 if (to_shinfo->nr_frags +
5352 from_shinfo->nr_frags > MAX_SKB_FRAGS)
5353 return false;
5354
5355 delta = from->truesize - SKB_TRUESIZE(skb_end_offset(from));
5356 }
5357
5358 WARN_ON_ONCE(delta < len);
5359
5360 memcpy(to_shinfo->frags + to_shinfo->nr_frags,
5361 from_shinfo->frags,
5362 from_shinfo->nr_frags * sizeof(skb_frag_t));
5363 to_shinfo->nr_frags += from_shinfo->nr_frags;
5364
5365 if (!skb_cloned(from))
5366 from_shinfo->nr_frags = 0;
5367
5368 /* if the skb is not cloned this does nothing
5369 * since we set nr_frags to 0.
5370 */
5371 for (i = 0; i < from_shinfo->nr_frags; i++)
5372 __skb_frag_ref(&from_shinfo->frags[i]);
5373
5374 to->truesize += delta;
5375 to->len += len;
5376 to->data_len += len;
5377
5378 *delta_truesize = delta;
5379 return true;
5380}
5381EXPORT_SYMBOL(skb_try_coalesce);
5382
5383/**
5384 * skb_scrub_packet - scrub an skb
5385 *
5386 * @skb: buffer to clean
5387 * @xnet: packet is crossing netns
5388 *
5389 * skb_scrub_packet can be used after encapsulating or decapsulting a packet
5390 * into/from a tunnel. Some information have to be cleared during these
5391 * operations.
5392 * skb_scrub_packet can also be used to clean a skb before injecting it in
5393 * another namespace (@xnet == true). We have to clear all information in the
5394 * skb that could impact namespace isolation.
5395 */
5396void skb_scrub_packet(struct sk_buff *skb, bool xnet)
5397{
5398 skb->pkt_type = PACKET_HOST;
5399 skb->skb_iif = 0;
5400 skb->ignore_df = 0;
5401 skb_dst_drop(skb);
5402 skb_ext_reset(skb);
5403 nf_reset_ct(skb);
5404 nf_reset_trace(skb);
5405
5406#ifdef CONFIG_NET_SWITCHDEV
5407 skb->offload_fwd_mark = 0;
5408 skb->offload_l3_fwd_mark = 0;
5409#endif
5410
5411 if (!xnet)
5412 return;
5413
5414 ipvs_reset(skb);
5415 skb->mark = 0;
5416 skb->tstamp = 0;
5417}
5418EXPORT_SYMBOL_GPL(skb_scrub_packet);
5419
5420/**
5421 * skb_gso_transport_seglen - Return length of individual segments of a gso packet
5422 *
5423 * @skb: GSO skb
5424 *
5425 * skb_gso_transport_seglen is used to determine the real size of the
5426 * individual segments, including Layer4 headers (TCP/UDP).
5427 *
5428 * The MAC/L2 or network (IP, IPv6) headers are not accounted for.
5429 */
5430static unsigned int skb_gso_transport_seglen(const struct sk_buff *skb)
5431{
5432 const struct skb_shared_info *shinfo = skb_shinfo(skb);
5433 unsigned int thlen = 0;
5434
5435 if (skb->encapsulation) {
5436 thlen = skb_inner_transport_header(skb) -
5437 skb_transport_header(skb);
5438
5439 if (likely(shinfo->gso_type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6)))
5440 thlen += inner_tcp_hdrlen(skb);
5441 } else if (likely(shinfo->gso_type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6))) {
5442 thlen = tcp_hdrlen(skb);
5443 } else if (unlikely(skb_is_gso_sctp(skb))) {
5444 thlen = sizeof(struct sctphdr);
5445 } else if (shinfo->gso_type & SKB_GSO_UDP_L4) {
5446 thlen = sizeof(struct udphdr);
5447 }
5448 /* UFO sets gso_size to the size of the fragmentation
5449 * payload, i.e. the size of the L4 (UDP) header is already
5450 * accounted for.
5451 */
5452 return thlen + shinfo->gso_size;
5453}
5454
5455/**
5456 * skb_gso_network_seglen - Return length of individual segments of a gso packet
5457 *
5458 * @skb: GSO skb
5459 *
5460 * skb_gso_network_seglen is used to determine the real size of the
5461 * individual segments, including Layer3 (IP, IPv6) and L4 headers (TCP/UDP).
5462 *
5463 * The MAC/L2 header is not accounted for.
5464 */
5465static unsigned int skb_gso_network_seglen(const struct sk_buff *skb)
5466{
5467 unsigned int hdr_len = skb_transport_header(skb) -
5468 skb_network_header(skb);
5469
5470 return hdr_len + skb_gso_transport_seglen(skb);
5471}
5472
5473/**
5474 * skb_gso_mac_seglen - Return length of individual segments of a gso packet
5475 *
5476 * @skb: GSO skb
5477 *
5478 * skb_gso_mac_seglen is used to determine the real size of the
5479 * individual segments, including MAC/L2, Layer3 (IP, IPv6) and L4
5480 * headers (TCP/UDP).
5481 */
5482static unsigned int skb_gso_mac_seglen(const struct sk_buff *skb)
5483{
5484 unsigned int hdr_len = skb_transport_header(skb) - skb_mac_header(skb);
5485
5486 return hdr_len + skb_gso_transport_seglen(skb);
5487}
5488
5489/**
5490 * skb_gso_size_check - check the skb size, considering GSO_BY_FRAGS
5491 *
5492 * There are a couple of instances where we have a GSO skb, and we
5493 * want to determine what size it would be after it is segmented.
5494 *
5495 * We might want to check:
5496 * - L3+L4+payload size (e.g. IP forwarding)
5497 * - L2+L3+L4+payload size (e.g. sanity check before passing to driver)
5498 *
5499 * This is a helper to do that correctly considering GSO_BY_FRAGS.
5500 *
5501 * @skb: GSO skb
5502 *
5503 * @seg_len: The segmented length (from skb_gso_*_seglen). In the
5504 * GSO_BY_FRAGS case this will be [header sizes + GSO_BY_FRAGS].
5505 *
5506 * @max_len: The maximum permissible length.
5507 *
5508 * Returns true if the segmented length <= max length.
5509 */
5510static inline bool skb_gso_size_check(const struct sk_buff *skb,
5511 unsigned int seg_len,
5512 unsigned int max_len) {
5513 const struct skb_shared_info *shinfo = skb_shinfo(skb);
5514 const struct sk_buff *iter;
5515
5516 if (shinfo->gso_size != GSO_BY_FRAGS)
5517 return seg_len <= max_len;
5518
5519 /* Undo this so we can re-use header sizes */
5520 seg_len -= GSO_BY_FRAGS;
5521
5522 skb_walk_frags(skb, iter) {
5523 if (seg_len + skb_headlen(iter) > max_len)
5524 return false;
5525 }
5526
5527 return true;
5528}
5529
5530/**
5531 * skb_gso_validate_network_len - Will a split GSO skb fit into a given MTU?
5532 *
5533 * @skb: GSO skb
5534 * @mtu: MTU to validate against
5535 *
5536 * skb_gso_validate_network_len validates if a given skb will fit a
5537 * wanted MTU once split. It considers L3 headers, L4 headers, and the
5538 * payload.
5539 */
5540bool skb_gso_validate_network_len(const struct sk_buff *skb, unsigned int mtu)
5541{
5542 return skb_gso_size_check(skb, skb_gso_network_seglen(skb), mtu);
5543}
5544EXPORT_SYMBOL_GPL(skb_gso_validate_network_len);
5545
5546/**
5547 * skb_gso_validate_mac_len - Will a split GSO skb fit in a given length?
5548 *
5549 * @skb: GSO skb
5550 * @len: length to validate against
5551 *
5552 * skb_gso_validate_mac_len validates if a given skb will fit a wanted
5553 * length once split, including L2, L3 and L4 headers and the payload.
5554 */
5555bool skb_gso_validate_mac_len(const struct sk_buff *skb, unsigned int len)
5556{
5557 return skb_gso_size_check(skb, skb_gso_mac_seglen(skb), len);
5558}
5559EXPORT_SYMBOL_GPL(skb_gso_validate_mac_len);
5560
5561static struct sk_buff *skb_reorder_vlan_header(struct sk_buff *skb)
5562{
5563 int mac_len, meta_len;
5564 void *meta;
5565
5566 if (skb_cow(skb, skb_headroom(skb)) < 0) {
5567 kfree_skb(skb);
5568 return NULL;
5569 }
5570
5571 mac_len = skb->data - skb_mac_header(skb);
5572 if (likely(mac_len > VLAN_HLEN + ETH_TLEN)) {
5573 memmove(skb_mac_header(skb) + VLAN_HLEN, skb_mac_header(skb),
5574 mac_len - VLAN_HLEN - ETH_TLEN);
5575 }
5576
5577 meta_len = skb_metadata_len(skb);
5578 if (meta_len) {
5579 meta = skb_metadata_end(skb) - meta_len;
5580 memmove(meta + VLAN_HLEN, meta, meta_len);
5581 }
5582
5583 skb->mac_header += VLAN_HLEN;
5584 return skb;
5585}
5586
5587struct sk_buff *skb_vlan_untag(struct sk_buff *skb)
5588{
5589 struct vlan_hdr *vhdr;
5590 u16 vlan_tci;
5591
5592 if (unlikely(skb_vlan_tag_present(skb))) {
5593 /* vlan_tci is already set-up so leave this for another time */
5594 return skb;
5595 }
5596
5597 skb = skb_share_check(skb, GFP_ATOMIC);
5598 if (unlikely(!skb))
5599 goto err_free;
5600 /* We may access the two bytes after vlan_hdr in vlan_set_encap_proto(). */
5601 if (unlikely(!pskb_may_pull(skb, VLAN_HLEN + sizeof(unsigned short))))
5602 goto err_free;
5603
5604 vhdr = (struct vlan_hdr *)skb->data;
5605 vlan_tci = ntohs(vhdr->h_vlan_TCI);
5606 __vlan_hwaccel_put_tag(skb, skb->protocol, vlan_tci);
5607
5608 skb_pull_rcsum(skb, VLAN_HLEN);
5609 vlan_set_encap_proto(skb, vhdr);
5610
5611 skb = skb_reorder_vlan_header(skb);
5612 if (unlikely(!skb))
5613 goto err_free;
5614
5615 skb_reset_network_header(skb);
5616 if (!skb_transport_header_was_set(skb))
5617 skb_reset_transport_header(skb);
5618 skb_reset_mac_len(skb);
5619
5620 return skb;
5621
5622err_free:
5623 kfree_skb(skb);
5624 return NULL;
5625}
5626EXPORT_SYMBOL(skb_vlan_untag);
5627
5628int skb_ensure_writable(struct sk_buff *skb, int write_len)
5629{
5630 if (!pskb_may_pull(skb, write_len))
5631 return -ENOMEM;
5632
5633 if (!skb_cloned(skb) || skb_clone_writable(skb, write_len))
5634 return 0;
5635
5636 return pskb_expand_head(skb, 0, 0, GFP_ATOMIC);
5637}
5638EXPORT_SYMBOL(skb_ensure_writable);
5639
5640/* remove VLAN header from packet and update csum accordingly.
5641 * expects a non skb_vlan_tag_present skb with a vlan tag payload
5642 */
5643int __skb_vlan_pop(struct sk_buff *skb, u16 *vlan_tci)
5644{
5645 struct vlan_hdr *vhdr;
5646 int offset = skb->data - skb_mac_header(skb);
5647 int err;
5648
5649 if (WARN_ONCE(offset,
5650 "__skb_vlan_pop got skb with skb->data not at mac header (offset %d)\n",
5651 offset)) {
5652 return -EINVAL;
5653 }
5654
5655 err = skb_ensure_writable(skb, VLAN_ETH_HLEN);
5656 if (unlikely(err))
5657 return err;
5658
5659 skb_postpull_rcsum(skb, skb->data + (2 * ETH_ALEN), VLAN_HLEN);
5660
5661 vhdr = (struct vlan_hdr *)(skb->data + ETH_HLEN);
5662 *vlan_tci = ntohs(vhdr->h_vlan_TCI);
5663
5664 memmove(skb->data + VLAN_HLEN, skb->data, 2 * ETH_ALEN);
5665 __skb_pull(skb, VLAN_HLEN);
5666
5667 vlan_set_encap_proto(skb, vhdr);
5668 skb->mac_header += VLAN_HLEN;
5669
5670 if (skb_network_offset(skb) < ETH_HLEN)
5671 skb_set_network_header(skb, ETH_HLEN);
5672
5673 skb_reset_mac_len(skb);
5674
5675 return err;
5676}
5677EXPORT_SYMBOL(__skb_vlan_pop);
5678
5679/* Pop a vlan tag either from hwaccel or from payload.
5680 * Expects skb->data at mac header.
5681 */
5682int skb_vlan_pop(struct sk_buff *skb)
5683{
5684 u16 vlan_tci;
5685 __be16 vlan_proto;
5686 int err;
5687
5688 if (likely(skb_vlan_tag_present(skb))) {
5689 __vlan_hwaccel_clear_tag(skb);
5690 } else {
5691 if (unlikely(!eth_type_vlan(skb->protocol)))
5692 return 0;
5693
5694 err = __skb_vlan_pop(skb, &vlan_tci);
5695 if (err)
5696 return err;
5697 }
5698 /* move next vlan tag to hw accel tag */
5699 if (likely(!eth_type_vlan(skb->protocol)))
5700 return 0;
5701
5702 vlan_proto = skb->protocol;
5703 err = __skb_vlan_pop(skb, &vlan_tci);
5704 if (unlikely(err))
5705 return err;
5706
5707 __vlan_hwaccel_put_tag(skb, vlan_proto, vlan_tci);
5708 return 0;
5709}
5710EXPORT_SYMBOL(skb_vlan_pop);
5711
5712/* Push a vlan tag either into hwaccel or into payload (if hwaccel tag present).
5713 * Expects skb->data at mac header.
5714 */
5715int skb_vlan_push(struct sk_buff *skb, __be16 vlan_proto, u16 vlan_tci)
5716{
5717 if (skb_vlan_tag_present(skb)) {
5718 int offset = skb->data - skb_mac_header(skb);
5719 int err;
5720
5721 if (WARN_ONCE(offset,
5722 "skb_vlan_push got skb with skb->data not at mac header (offset %d)\n",
5723 offset)) {
5724 return -EINVAL;
5725 }
5726
5727 err = __vlan_insert_tag(skb, skb->vlan_proto,
5728 skb_vlan_tag_get(skb));
5729 if (err)
5730 return err;
5731
5732 skb->protocol = skb->vlan_proto;
5733 skb->mac_len += VLAN_HLEN;
5734
5735 skb_postpush_rcsum(skb, skb->data + (2 * ETH_ALEN), VLAN_HLEN);
5736 }
5737 __vlan_hwaccel_put_tag(skb, vlan_proto, vlan_tci);
5738 return 0;
5739}
5740EXPORT_SYMBOL(skb_vlan_push);
5741
5742/**
5743 * skb_eth_pop() - Drop the Ethernet header at the head of a packet
5744 *
5745 * @skb: Socket buffer to modify
5746 *
5747 * Drop the Ethernet header of @skb.
5748 *
5749 * Expects that skb->data points to the mac header and that no VLAN tags are
5750 * present.
5751 *
5752 * Returns 0 on success, -errno otherwise.
5753 */
5754int skb_eth_pop(struct sk_buff *skb)
5755{
5756 if (!pskb_may_pull(skb, ETH_HLEN) || skb_vlan_tagged(skb) ||
5757 skb_network_offset(skb) < ETH_HLEN)
5758 return -EPROTO;
5759
5760 skb_pull_rcsum(skb, ETH_HLEN);
5761 skb_reset_mac_header(skb);
5762 skb_reset_mac_len(skb);
5763
5764 return 0;
5765}
5766EXPORT_SYMBOL(skb_eth_pop);
5767
5768/**
5769 * skb_eth_push() - Add a new Ethernet header at the head of a packet
5770 *
5771 * @skb: Socket buffer to modify
5772 * @dst: Destination MAC address of the new header
5773 * @src: Source MAC address of the new header
5774 *
5775 * Prepend @skb with a new Ethernet header.
5776 *
5777 * Expects that skb->data points to the mac header, which must be empty.
5778 *
5779 * Returns 0 on success, -errno otherwise.
5780 */
5781int skb_eth_push(struct sk_buff *skb, const unsigned char *dst,
5782 const unsigned char *src)
5783{
5784 struct ethhdr *eth;
5785 int err;
5786
5787 if (skb_network_offset(skb) || skb_vlan_tag_present(skb))
5788 return -EPROTO;
5789
5790 err = skb_cow_head(skb, sizeof(*eth));
5791 if (err < 0)
5792 return err;
5793
5794 skb_push(skb, sizeof(*eth));
5795 skb_reset_mac_header(skb);
5796 skb_reset_mac_len(skb);
5797
5798 eth = eth_hdr(skb);
5799 ether_addr_copy(eth->h_dest, dst);
5800 ether_addr_copy(eth->h_source, src);
5801 eth->h_proto = skb->protocol;
5802
5803 skb_postpush_rcsum(skb, eth, sizeof(*eth));
5804
5805 return 0;
5806}
5807EXPORT_SYMBOL(skb_eth_push);
5808
5809/* Update the ethertype of hdr and the skb csum value if required. */
5810static void skb_mod_eth_type(struct sk_buff *skb, struct ethhdr *hdr,
5811 __be16 ethertype)
5812{
5813 if (skb->ip_summed == CHECKSUM_COMPLETE) {
5814 __be16 diff[] = { ~hdr->h_proto, ethertype };
5815
5816 skb->csum = csum_partial((char *)diff, sizeof(diff), skb->csum);
5817 }
5818
5819 hdr->h_proto = ethertype;
5820}
5821
5822/**
5823 * skb_mpls_push() - push a new MPLS header after mac_len bytes from start of
5824 * the packet
5825 *
5826 * @skb: buffer
5827 * @mpls_lse: MPLS label stack entry to push
5828 * @mpls_proto: ethertype of the new MPLS header (expects 0x8847 or 0x8848)
5829 * @mac_len: length of the MAC header
5830 * @ethernet: flag to indicate if the resulting packet after skb_mpls_push is
5831 * ethernet
5832 *
5833 * Expects skb->data at mac header.
5834 *
5835 * Returns 0 on success, -errno otherwise.
5836 */
5837int skb_mpls_push(struct sk_buff *skb, __be32 mpls_lse, __be16 mpls_proto,
5838 int mac_len, bool ethernet)
5839{
5840 struct mpls_shim_hdr *lse;
5841 int err;
5842
5843 if (unlikely(!eth_p_mpls(mpls_proto)))
5844 return -EINVAL;
5845
5846 /* Networking stack does not allow simultaneous Tunnel and MPLS GSO. */
5847 if (skb->encapsulation)
5848 return -EINVAL;
5849
5850 err = skb_cow_head(skb, MPLS_HLEN);
5851 if (unlikely(err))
5852 return err;
5853
5854 if (!skb->inner_protocol) {
5855 skb_set_inner_network_header(skb, skb_network_offset(skb));
5856 skb_set_inner_protocol(skb, skb->protocol);
5857 }
5858
5859 skb_push(skb, MPLS_HLEN);
5860 memmove(skb_mac_header(skb) - MPLS_HLEN, skb_mac_header(skb),
5861 mac_len);
5862 skb_reset_mac_header(skb);
5863 skb_set_network_header(skb, mac_len);
5864 skb_reset_mac_len(skb);
5865
5866 lse = mpls_hdr(skb);
5867 lse->label_stack_entry = mpls_lse;
5868 skb_postpush_rcsum(skb, lse, MPLS_HLEN);
5869
5870 if (ethernet && mac_len >= ETH_HLEN)
5871 skb_mod_eth_type(skb, eth_hdr(skb), mpls_proto);
5872 skb->protocol = mpls_proto;
5873
5874 return 0;
5875}
5876EXPORT_SYMBOL_GPL(skb_mpls_push);
5877
5878/**
5879 * skb_mpls_pop() - pop the outermost MPLS header
5880 *
5881 * @skb: buffer
5882 * @next_proto: ethertype of header after popped MPLS header
5883 * @mac_len: length of the MAC header
5884 * @ethernet: flag to indicate if the packet is ethernet
5885 *
5886 * Expects skb->data at mac header.
5887 *
5888 * Returns 0 on success, -errno otherwise.
5889 */
5890int skb_mpls_pop(struct sk_buff *skb, __be16 next_proto, int mac_len,
5891 bool ethernet)
5892{
5893 int err;
5894
5895 if (unlikely(!eth_p_mpls(skb->protocol)))
5896 return 0;
5897
5898 err = skb_ensure_writable(skb, mac_len + MPLS_HLEN);
5899 if (unlikely(err))
5900 return err;
5901
5902 skb_postpull_rcsum(skb, mpls_hdr(skb), MPLS_HLEN);
5903 memmove(skb_mac_header(skb) + MPLS_HLEN, skb_mac_header(skb),
5904 mac_len);
5905
5906 __skb_pull(skb, MPLS_HLEN);
5907 skb_reset_mac_header(skb);
5908 skb_set_network_header(skb, mac_len);
5909
5910 if (ethernet && mac_len >= ETH_HLEN) {
5911 struct ethhdr *hdr;
5912
5913 /* use mpls_hdr() to get ethertype to account for VLANs. */
5914 hdr = (struct ethhdr *)((void *)mpls_hdr(skb) - ETH_HLEN);
5915 skb_mod_eth_type(skb, hdr, next_proto);
5916 }
5917 skb->protocol = next_proto;
5918
5919 return 0;
5920}
5921EXPORT_SYMBOL_GPL(skb_mpls_pop);
5922
5923/**
5924 * skb_mpls_update_lse() - modify outermost MPLS header and update csum
5925 *
5926 * @skb: buffer
5927 * @mpls_lse: new MPLS label stack entry to update to
5928 *
5929 * Expects skb->data at mac header.
5930 *
5931 * Returns 0 on success, -errno otherwise.
5932 */
5933int skb_mpls_update_lse(struct sk_buff *skb, __be32 mpls_lse)
5934{
5935 int err;
5936
5937 if (unlikely(!eth_p_mpls(skb->protocol)))
5938 return -EINVAL;
5939
5940 err = skb_ensure_writable(skb, skb->mac_len + MPLS_HLEN);
5941 if (unlikely(err))
5942 return err;
5943
5944 if (skb->ip_summed == CHECKSUM_COMPLETE) {
5945 __be32 diff[] = { ~mpls_hdr(skb)->label_stack_entry, mpls_lse };
5946
5947 skb->csum = csum_partial((char *)diff, sizeof(diff), skb->csum);
5948 }
5949
5950 mpls_hdr(skb)->label_stack_entry = mpls_lse;
5951
5952 return 0;
5953}
5954EXPORT_SYMBOL_GPL(skb_mpls_update_lse);
5955
5956/**
5957 * skb_mpls_dec_ttl() - decrement the TTL of the outermost MPLS header
5958 *
5959 * @skb: buffer
5960 *
5961 * Expects skb->data at mac header.
5962 *
5963 * Returns 0 on success, -errno otherwise.
5964 */
5965int skb_mpls_dec_ttl(struct sk_buff *skb)
5966{
5967 u32 lse;
5968 u8 ttl;
5969
5970 if (unlikely(!eth_p_mpls(skb->protocol)))
5971 return -EINVAL;
5972
5973 if (!pskb_may_pull(skb, skb_network_offset(skb) + MPLS_HLEN))
5974 return -ENOMEM;
5975
5976 lse = be32_to_cpu(mpls_hdr(skb)->label_stack_entry);
5977 ttl = (lse & MPLS_LS_TTL_MASK) >> MPLS_LS_TTL_SHIFT;
5978 if (!--ttl)
5979 return -EINVAL;
5980
5981 lse &= ~MPLS_LS_TTL_MASK;
5982 lse |= ttl << MPLS_LS_TTL_SHIFT;
5983
5984 return skb_mpls_update_lse(skb, cpu_to_be32(lse));
5985}
5986EXPORT_SYMBOL_GPL(skb_mpls_dec_ttl);
5987
5988/**
5989 * alloc_skb_with_frags - allocate skb with page frags
5990 *
5991 * @header_len: size of linear part
5992 * @data_len: needed length in frags
5993 * @max_page_order: max page order desired.
5994 * @errcode: pointer to error code if any
5995 * @gfp_mask: allocation mask
5996 *
5997 * This can be used to allocate a paged skb, given a maximal order for frags.
5998 */
5999struct sk_buff *alloc_skb_with_frags(unsigned long header_len,
6000 unsigned long data_len,
6001 int max_page_order,
6002 int *errcode,
6003 gfp_t gfp_mask)
6004{
6005 int npages = (data_len + (PAGE_SIZE - 1)) >> PAGE_SHIFT;
6006 unsigned long chunk;
6007 struct sk_buff *skb;
6008 struct page *page;
6009 int i;
6010
6011 *errcode = -EMSGSIZE;
6012 /* Note this test could be relaxed, if we succeed to allocate
6013 * high order pages...
6014 */
6015 if (npages > MAX_SKB_FRAGS)
6016 return NULL;
6017
6018 *errcode = -ENOBUFS;
6019 skb = alloc_skb(header_len, gfp_mask);
6020 if (!skb)
6021 return NULL;
6022
6023 skb->truesize += npages << PAGE_SHIFT;
6024
6025 for (i = 0; npages > 0; i++) {
6026 int order = max_page_order;
6027
6028 while (order) {
6029 if (npages >= 1 << order) {
6030 page = alloc_pages((gfp_mask & ~__GFP_DIRECT_RECLAIM) |
6031 __GFP_COMP |
6032 __GFP_NOWARN,
6033 order);
6034 if (page)
6035 goto fill_page;
6036 /* Do not retry other high order allocations */
6037 order = 1;
6038 max_page_order = 0;
6039 }
6040 order--;
6041 }
6042 page = alloc_page(gfp_mask);
6043 if (!page)
6044 goto failure;
6045fill_page:
6046 chunk = min_t(unsigned long, data_len,
6047 PAGE_SIZE << order);
6048 skb_fill_page_desc(skb, i, page, 0, chunk);
6049 data_len -= chunk;
6050 npages -= 1 << order;
6051 }
6052 return skb;
6053
6054failure:
6055 kfree_skb(skb);
6056 return NULL;
6057}
6058EXPORT_SYMBOL(alloc_skb_with_frags);
6059
6060/* carve out the first off bytes from skb when off < headlen */
6061static int pskb_carve_inside_header(struct sk_buff *skb, const u32 off,
6062 const int headlen, gfp_t gfp_mask)
6063{
6064 int i;
6065 int size = skb_end_offset(skb);
6066 int new_hlen = headlen - off;
6067 u8 *data;
6068
6069 size = SKB_DATA_ALIGN(size);
6070
6071 if (skb_pfmemalloc(skb))
6072 gfp_mask |= __GFP_MEMALLOC;
6073 data = kmalloc_reserve(size +
6074 SKB_DATA_ALIGN(sizeof(struct skb_shared_info)),
6075 gfp_mask, NUMA_NO_NODE, NULL);
6076 if (!data)
6077 return -ENOMEM;
6078
6079 size = SKB_WITH_OVERHEAD(ksize(data));
6080
6081 /* Copy real data, and all frags */
6082 skb_copy_from_linear_data_offset(skb, off, data, new_hlen);
6083 skb->len -= off;
6084
6085 memcpy((struct skb_shared_info *)(data + size),
6086 skb_shinfo(skb),
6087 offsetof(struct skb_shared_info,
6088 frags[skb_shinfo(skb)->nr_frags]));
6089 if (skb_cloned(skb)) {
6090 /* drop the old head gracefully */
6091 if (skb_orphan_frags(skb, gfp_mask)) {
6092 kfree(data);
6093 return -ENOMEM;
6094 }
6095 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
6096 skb_frag_ref(skb, i);
6097 if (skb_has_frag_list(skb))
6098 skb_clone_fraglist(skb);
6099 skb_release_data(skb);
6100 } else {
6101 /* we can reuse existing recount- all we did was
6102 * relocate values
6103 */
6104 skb_free_head(skb);
6105 }
6106
6107 skb->head = data;
6108 skb->data = data;
6109 skb->head_frag = 0;
6110#ifdef NET_SKBUFF_DATA_USES_OFFSET
6111 skb->end = size;
6112#else
6113 skb->end = skb->head + size;
6114#endif
6115 skb_set_tail_pointer(skb, skb_headlen(skb));
6116 skb_headers_offset_update(skb, 0);
6117 skb->cloned = 0;
6118 skb->hdr_len = 0;
6119 skb->nohdr = 0;
6120 atomic_set(&skb_shinfo(skb)->dataref, 1);
6121
6122 return 0;
6123}
6124
6125static int pskb_carve(struct sk_buff *skb, const u32 off, gfp_t gfp);
6126
6127/* carve out the first eat bytes from skb's frag_list. May recurse into
6128 * pskb_carve()
6129 */
6130static int pskb_carve_frag_list(struct sk_buff *skb,
6131 struct skb_shared_info *shinfo, int eat,
6132 gfp_t gfp_mask)
6133{
6134 struct sk_buff *list = shinfo->frag_list;
6135 struct sk_buff *clone = NULL;
6136 struct sk_buff *insp = NULL;
6137
6138 do {
6139 if (!list) {
6140 pr_err("Not enough bytes to eat. Want %d\n", eat);
6141 return -EFAULT;
6142 }
6143 if (list->len <= eat) {
6144 /* Eaten as whole. */
6145 eat -= list->len;
6146 list = list->next;
6147 insp = list;
6148 } else {
6149 /* Eaten partially. */
6150 if (skb_shared(list)) {
6151 clone = skb_clone(list, gfp_mask);
6152 if (!clone)
6153 return -ENOMEM;
6154 insp = list->next;
6155 list = clone;
6156 } else {
6157 /* This may be pulled without problems. */
6158 insp = list;
6159 }
6160 if (pskb_carve(list, eat, gfp_mask) < 0) {
6161 kfree_skb(clone);
6162 return -ENOMEM;
6163 }
6164 break;
6165 }
6166 } while (eat);
6167
6168 /* Free pulled out fragments. */
6169 while ((list = shinfo->frag_list) != insp) {
6170 shinfo->frag_list = list->next;
6171 kfree_skb(list);
6172 }
6173 /* And insert new clone at head. */
6174 if (clone) {
6175 clone->next = list;
6176 shinfo->frag_list = clone;
6177 }
6178 return 0;
6179}
6180
6181/* carve off first len bytes from skb. Split line (off) is in the
6182 * non-linear part of skb
6183 */
6184static int pskb_carve_inside_nonlinear(struct sk_buff *skb, const u32 off,
6185 int pos, gfp_t gfp_mask)
6186{
6187 int i, k = 0;
6188 int size = skb_end_offset(skb);
6189 u8 *data;
6190 const int nfrags = skb_shinfo(skb)->nr_frags;
6191 struct skb_shared_info *shinfo;
6192
6193 size = SKB_DATA_ALIGN(size);
6194
6195 if (skb_pfmemalloc(skb))
6196 gfp_mask |= __GFP_MEMALLOC;
6197 data = kmalloc_reserve(size +
6198 SKB_DATA_ALIGN(sizeof(struct skb_shared_info)),
6199 gfp_mask, NUMA_NO_NODE, NULL);
6200 if (!data)
6201 return -ENOMEM;
6202
6203 size = SKB_WITH_OVERHEAD(ksize(data));
6204
6205 memcpy((struct skb_shared_info *)(data + size),
6206 skb_shinfo(skb), offsetof(struct skb_shared_info, frags[0]));
6207 if (skb_orphan_frags(skb, gfp_mask)) {
6208 kfree(data);
6209 return -ENOMEM;
6210 }
6211 shinfo = (struct skb_shared_info *)(data + size);
6212 for (i = 0; i < nfrags; i++) {
6213 int fsize = skb_frag_size(&skb_shinfo(skb)->frags[i]);
6214
6215 if (pos + fsize > off) {
6216 shinfo->frags[k] = skb_shinfo(skb)->frags[i];
6217
6218 if (pos < off) {
6219 /* Split frag.
6220 * We have two variants in this case:
6221 * 1. Move all the frag to the second
6222 * part, if it is possible. F.e.
6223 * this approach is mandatory for TUX,
6224 * where splitting is expensive.
6225 * 2. Split is accurately. We make this.
6226 */
6227 skb_frag_off_add(&shinfo->frags[0], off - pos);
6228 skb_frag_size_sub(&shinfo->frags[0], off - pos);
6229 }
6230 skb_frag_ref(skb, i);
6231 k++;
6232 }
6233 pos += fsize;
6234 }
6235 shinfo->nr_frags = k;
6236 if (skb_has_frag_list(skb))
6237 skb_clone_fraglist(skb);
6238
6239 /* split line is in frag list */
6240 if (k == 0 && pskb_carve_frag_list(skb, shinfo, off - pos, gfp_mask)) {
6241 /* skb_frag_unref() is not needed here as shinfo->nr_frags = 0. */
6242 if (skb_has_frag_list(skb))
6243 kfree_skb_list(skb_shinfo(skb)->frag_list);
6244 kfree(data);
6245 return -ENOMEM;
6246 }
6247 skb_release_data(skb);
6248
6249 skb->head = data;
6250 skb->head_frag = 0;
6251 skb->data = data;
6252#ifdef NET_SKBUFF_DATA_USES_OFFSET
6253 skb->end = size;
6254#else
6255 skb->end = skb->head + size;
6256#endif
6257 skb_reset_tail_pointer(skb);
6258 skb_headers_offset_update(skb, 0);
6259 skb->cloned = 0;
6260 skb->hdr_len = 0;
6261 skb->nohdr = 0;
6262 skb->len -= off;
6263 skb->data_len = skb->len;
6264 atomic_set(&skb_shinfo(skb)->dataref, 1);
6265 return 0;
6266}
6267
6268/* remove len bytes from the beginning of the skb */
6269static int pskb_carve(struct sk_buff *skb, const u32 len, gfp_t gfp)
6270{
6271 int headlen = skb_headlen(skb);
6272
6273 if (len < headlen)
6274 return pskb_carve_inside_header(skb, len, headlen, gfp);
6275 else
6276 return pskb_carve_inside_nonlinear(skb, len, headlen, gfp);
6277}
6278
6279/* Extract to_copy bytes starting at off from skb, and return this in
6280 * a new skb
6281 */
6282struct sk_buff *pskb_extract(struct sk_buff *skb, int off,
6283 int to_copy, gfp_t gfp)
6284{
6285 struct sk_buff *clone = skb_clone(skb, gfp);
6286
6287 if (!clone)
6288 return NULL;
6289
6290 if (pskb_carve(clone, off, gfp) < 0 ||
6291 pskb_trim(clone, to_copy)) {
6292 kfree_skb(clone);
6293 return NULL;
6294 }
6295 return clone;
6296}
6297EXPORT_SYMBOL(pskb_extract);
6298
6299/**
6300 * skb_condense - try to get rid of fragments/frag_list if possible
6301 * @skb: buffer
6302 *
6303 * Can be used to save memory before skb is added to a busy queue.
6304 * If packet has bytes in frags and enough tail room in skb->head,
6305 * pull all of them, so that we can free the frags right now and adjust
6306 * truesize.
6307 * Notes:
6308 * We do not reallocate skb->head thus can not fail.
6309 * Caller must re-evaluate skb->truesize if needed.
6310 */
6311void skb_condense(struct sk_buff *skb)
6312{
6313 if (skb->data_len) {
6314 if (skb->data_len > skb->end - skb->tail ||
6315 skb_cloned(skb))
6316 return;
6317
6318 /* Nice, we can free page frag(s) right now */
6319 __pskb_pull_tail(skb, skb->data_len);
6320 }
6321 /* At this point, skb->truesize might be over estimated,
6322 * because skb had a fragment, and fragments do not tell
6323 * their truesize.
6324 * When we pulled its content into skb->head, fragment
6325 * was freed, but __pskb_pull_tail() could not possibly
6326 * adjust skb->truesize, not knowing the frag truesize.
6327 */
6328 skb->truesize = SKB_TRUESIZE(skb_end_offset(skb));
6329}
6330
6331#ifdef CONFIG_SKB_EXTENSIONS
6332static void *skb_ext_get_ptr(struct skb_ext *ext, enum skb_ext_id id)
6333{
6334 return (void *)ext + (ext->offset[id] * SKB_EXT_ALIGN_VALUE);
6335}
6336
6337/**
6338 * __skb_ext_alloc - allocate a new skb extensions storage
6339 *
6340 * @flags: See kmalloc().
6341 *
6342 * Returns the newly allocated pointer. The pointer can later attached to a
6343 * skb via __skb_ext_set().
6344 * Note: caller must handle the skb_ext as an opaque data.
6345 */
6346struct skb_ext *__skb_ext_alloc(gfp_t flags)
6347{
6348 struct skb_ext *new = kmem_cache_alloc(skbuff_ext_cache, flags);
6349
6350 if (new) {
6351 memset(new->offset, 0, sizeof(new->offset));
6352 refcount_set(&new->refcnt, 1);
6353 }
6354
6355 return new;
6356}
6357
6358static struct skb_ext *skb_ext_maybe_cow(struct skb_ext *old,
6359 unsigned int old_active)
6360{
6361 struct skb_ext *new;
6362
6363 if (refcount_read(&old->refcnt) == 1)
6364 return old;
6365
6366 new = kmem_cache_alloc(skbuff_ext_cache, GFP_ATOMIC);
6367 if (!new)
6368 return NULL;
6369
6370 memcpy(new, old, old->chunks * SKB_EXT_ALIGN_VALUE);
6371 refcount_set(&new->refcnt, 1);
6372
6373#ifdef CONFIG_XFRM
6374 if (old_active & (1 << SKB_EXT_SEC_PATH)) {
6375 struct sec_path *sp = skb_ext_get_ptr(old, SKB_EXT_SEC_PATH);
6376 unsigned int i;
6377
6378 for (i = 0; i < sp->len; i++)
6379 xfrm_state_hold(sp->xvec[i]);
6380 }
6381#endif
6382 __skb_ext_put(old);
6383 return new;
6384}
6385
6386/**
6387 * __skb_ext_set - attach the specified extension storage to this skb
6388 * @skb: buffer
6389 * @id: extension id
6390 * @ext: extension storage previously allocated via __skb_ext_alloc()
6391 *
6392 * Existing extensions, if any, are cleared.
6393 *
6394 * Returns the pointer to the extension.
6395 */
6396void *__skb_ext_set(struct sk_buff *skb, enum skb_ext_id id,
6397 struct skb_ext *ext)
6398{
6399 unsigned int newlen, newoff = SKB_EXT_CHUNKSIZEOF(*ext);
6400
6401 skb_ext_put(skb);
6402 newlen = newoff + skb_ext_type_len[id];
6403 ext->chunks = newlen;
6404 ext->offset[id] = newoff;
6405 skb->extensions = ext;
6406 skb->active_extensions = 1 << id;
6407 return skb_ext_get_ptr(ext, id);
6408}
6409
6410/**
6411 * skb_ext_add - allocate space for given extension, COW if needed
6412 * @skb: buffer
6413 * @id: extension to allocate space for
6414 *
6415 * Allocates enough space for the given extension.
6416 * If the extension is already present, a pointer to that extension
6417 * is returned.
6418 *
6419 * If the skb was cloned, COW applies and the returned memory can be
6420 * modified without changing the extension space of clones buffers.
6421 *
6422 * Returns pointer to the extension or NULL on allocation failure.
6423 */
6424void *skb_ext_add(struct sk_buff *skb, enum skb_ext_id id)
6425{
6426 struct skb_ext *new, *old = NULL;
6427 unsigned int newlen, newoff;
6428
6429 if (skb->active_extensions) {
6430 old = skb->extensions;
6431
6432 new = skb_ext_maybe_cow(old, skb->active_extensions);
6433 if (!new)
6434 return NULL;
6435
6436 if (__skb_ext_exist(new, id))
6437 goto set_active;
6438
6439 newoff = new->chunks;
6440 } else {
6441 newoff = SKB_EXT_CHUNKSIZEOF(*new);
6442
6443 new = __skb_ext_alloc(GFP_ATOMIC);
6444 if (!new)
6445 return NULL;
6446 }
6447
6448 newlen = newoff + skb_ext_type_len[id];
6449 new->chunks = newlen;
6450 new->offset[id] = newoff;
6451set_active:
6452 skb->extensions = new;
6453 skb->active_extensions |= 1 << id;
6454 return skb_ext_get_ptr(new, id);
6455}
6456EXPORT_SYMBOL(skb_ext_add);
6457
6458#ifdef CONFIG_XFRM
6459static void skb_ext_put_sp(struct sec_path *sp)
6460{
6461 unsigned int i;
6462
6463 for (i = 0; i < sp->len; i++)
6464 xfrm_state_put(sp->xvec[i]);
6465}
6466#endif
6467
6468void __skb_ext_del(struct sk_buff *skb, enum skb_ext_id id)
6469{
6470 struct skb_ext *ext = skb->extensions;
6471
6472 skb->active_extensions &= ~(1 << id);
6473 if (skb->active_extensions == 0) {
6474 skb->extensions = NULL;
6475 __skb_ext_put(ext);
6476#ifdef CONFIG_XFRM
6477 } else if (id == SKB_EXT_SEC_PATH &&
6478 refcount_read(&ext->refcnt) == 1) {
6479 struct sec_path *sp = skb_ext_get_ptr(ext, SKB_EXT_SEC_PATH);
6480
6481 skb_ext_put_sp(sp);
6482 sp->len = 0;
6483#endif
6484 }
6485}
6486EXPORT_SYMBOL(__skb_ext_del);
6487
6488void __skb_ext_put(struct skb_ext *ext)
6489{
6490 /* If this is last clone, nothing can increment
6491 * it after check passes. Avoids one atomic op.
6492 */
6493 if (refcount_read(&ext->refcnt) == 1)
6494 goto free_now;
6495
6496 if (!refcount_dec_and_test(&ext->refcnt))
6497 return;
6498free_now:
6499#ifdef CONFIG_XFRM
6500 if (__skb_ext_exist(ext, SKB_EXT_SEC_PATH))
6501 skb_ext_put_sp(skb_ext_get_ptr(ext, SKB_EXT_SEC_PATH));
6502#endif
6503
6504 kmem_cache_free(skbuff_ext_cache, ext);
6505}
6506EXPORT_SYMBOL(__skb_ext_put);
6507#endif /* CONFIG_SKB_EXTENSIONS */
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/netdevice.h>
51#ifdef CONFIG_NET_CLS_ACT
52#include <net/pkt_sched.h>
53#endif
54#include <linux/string.h>
55#include <linux/skbuff.h>
56#include <linux/splice.h>
57#include <linux/cache.h>
58#include <linux/rtnetlink.h>
59#include <linux/init.h>
60#include <linux/scatterlist.h>
61#include <linux/errqueue.h>
62#include <linux/prefetch.h>
63
64#include <net/protocol.h>
65#include <net/dst.h>
66#include <net/sock.h>
67#include <net/checksum.h>
68#include <net/xfrm.h>
69
70#include <asm/uaccess.h>
71#include <trace/events/skb.h>
72#include <linux/highmem.h>
73
74struct kmem_cache *skbuff_head_cache __read_mostly;
75static struct kmem_cache *skbuff_fclone_cache __read_mostly;
76
77static void sock_pipe_buf_release(struct pipe_inode_info *pipe,
78 struct pipe_buffer *buf)
79{
80 put_page(buf->page);
81}
82
83static void sock_pipe_buf_get(struct pipe_inode_info *pipe,
84 struct pipe_buffer *buf)
85{
86 get_page(buf->page);
87}
88
89static int sock_pipe_buf_steal(struct pipe_inode_info *pipe,
90 struct pipe_buffer *buf)
91{
92 return 1;
93}
94
95
96/* Pipe buffer operations for a socket. */
97static const struct pipe_buf_operations sock_pipe_buf_ops = {
98 .can_merge = 0,
99 .map = generic_pipe_buf_map,
100 .unmap = generic_pipe_buf_unmap,
101 .confirm = generic_pipe_buf_confirm,
102 .release = sock_pipe_buf_release,
103 .steal = sock_pipe_buf_steal,
104 .get = sock_pipe_buf_get,
105};
106
107/*
108 * Keep out-of-line to prevent kernel bloat.
109 * __builtin_return_address is not used because it is not always
110 * reliable.
111 */
112
113/**
114 * skb_over_panic - private function
115 * @skb: buffer
116 * @sz: size
117 * @here: address
118 *
119 * Out of line support code for skb_put(). Not user callable.
120 */
121static void skb_over_panic(struct sk_buff *skb, int sz, void *here)
122{
123 pr_emerg("%s: text:%p len:%d put:%d head:%p data:%p tail:%#lx end:%#lx dev:%s\n",
124 __func__, here, skb->len, sz, skb->head, skb->data,
125 (unsigned long)skb->tail, (unsigned long)skb->end,
126 skb->dev ? skb->dev->name : "<NULL>");
127 BUG();
128}
129
130/**
131 * skb_under_panic - private function
132 * @skb: buffer
133 * @sz: size
134 * @here: address
135 *
136 * Out of line support code for skb_push(). Not user callable.
137 */
138
139static void skb_under_panic(struct sk_buff *skb, int sz, void *here)
140{
141 pr_emerg("%s: text:%p len:%d put:%d head:%p data:%p tail:%#lx end:%#lx dev:%s\n",
142 __func__, here, skb->len, sz, skb->head, skb->data,
143 (unsigned long)skb->tail, (unsigned long)skb->end,
144 skb->dev ? skb->dev->name : "<NULL>");
145 BUG();
146}
147
148/* Allocate a new skbuff. We do this ourselves so we can fill in a few
149 * 'private' fields and also do memory statistics to find all the
150 * [BEEP] leaks.
151 *
152 */
153
154/**
155 * __alloc_skb - allocate a network buffer
156 * @size: size to allocate
157 * @gfp_mask: allocation mask
158 * @fclone: allocate from fclone cache instead of head cache
159 * and allocate a cloned (child) skb
160 * @node: numa node to allocate memory on
161 *
162 * Allocate a new &sk_buff. The returned buffer has no headroom and a
163 * tail room of size bytes. The object has a reference count of one.
164 * The return is the buffer. On a failure the return is %NULL.
165 *
166 * Buffers may only be allocated from interrupts using a @gfp_mask of
167 * %GFP_ATOMIC.
168 */
169struct sk_buff *__alloc_skb(unsigned int size, gfp_t gfp_mask,
170 int fclone, int node)
171{
172 struct kmem_cache *cache;
173 struct skb_shared_info *shinfo;
174 struct sk_buff *skb;
175 u8 *data;
176
177 cache = fclone ? skbuff_fclone_cache : skbuff_head_cache;
178
179 /* Get the HEAD */
180 skb = kmem_cache_alloc_node(cache, gfp_mask & ~__GFP_DMA, node);
181 if (!skb)
182 goto out;
183 prefetchw(skb);
184
185 /* We do our best to align skb_shared_info on a separate cache
186 * line. It usually works because kmalloc(X > SMP_CACHE_BYTES) gives
187 * aligned memory blocks, unless SLUB/SLAB debug is enabled.
188 * Both skb->head and skb_shared_info are cache line aligned.
189 */
190 size = SKB_DATA_ALIGN(size);
191 size += SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
192 data = kmalloc_node_track_caller(size, gfp_mask, node);
193 if (!data)
194 goto nodata;
195 /* kmalloc(size) might give us more room than requested.
196 * Put skb_shared_info exactly at the end of allocated zone,
197 * to allow max possible filling before reallocation.
198 */
199 size = SKB_WITH_OVERHEAD(ksize(data));
200 prefetchw(data + size);
201
202 /*
203 * Only clear those fields we need to clear, not those that we will
204 * actually initialise below. Hence, don't put any more fields after
205 * the tail pointer in struct sk_buff!
206 */
207 memset(skb, 0, offsetof(struct sk_buff, tail));
208 /* Account for allocated memory : skb + skb->head */
209 skb->truesize = SKB_TRUESIZE(size);
210 atomic_set(&skb->users, 1);
211 skb->head = data;
212 skb->data = data;
213 skb_reset_tail_pointer(skb);
214 skb->end = skb->tail + size;
215#ifdef NET_SKBUFF_DATA_USES_OFFSET
216 skb->mac_header = ~0U;
217#endif
218
219 /* make sure we initialize shinfo sequentially */
220 shinfo = skb_shinfo(skb);
221 memset(shinfo, 0, offsetof(struct skb_shared_info, dataref));
222 atomic_set(&shinfo->dataref, 1);
223 kmemcheck_annotate_variable(shinfo->destructor_arg);
224
225 if (fclone) {
226 struct sk_buff *child = skb + 1;
227 atomic_t *fclone_ref = (atomic_t *) (child + 1);
228
229 kmemcheck_annotate_bitfield(child, flags1);
230 kmemcheck_annotate_bitfield(child, flags2);
231 skb->fclone = SKB_FCLONE_ORIG;
232 atomic_set(fclone_ref, 1);
233
234 child->fclone = SKB_FCLONE_UNAVAILABLE;
235 }
236out:
237 return skb;
238nodata:
239 kmem_cache_free(cache, skb);
240 skb = NULL;
241 goto out;
242}
243EXPORT_SYMBOL(__alloc_skb);
244
245/**
246 * build_skb - build a network buffer
247 * @data: data buffer provided by caller
248 * @frag_size: size of fragment, or 0 if head was kmalloced
249 *
250 * Allocate a new &sk_buff. Caller provides space holding head and
251 * skb_shared_info. @data must have been allocated by kmalloc()
252 * The return is the new skb buffer.
253 * On a failure the return is %NULL, and @data is not freed.
254 * Notes :
255 * Before IO, driver allocates only data buffer where NIC put incoming frame
256 * Driver should add room at head (NET_SKB_PAD) and
257 * MUST add room at tail (SKB_DATA_ALIGN(skb_shared_info))
258 * After IO, driver calls build_skb(), to allocate sk_buff and populate it
259 * before giving packet to stack.
260 * RX rings only contains data buffers, not full skbs.
261 */
262struct sk_buff *build_skb(void *data, unsigned int frag_size)
263{
264 struct skb_shared_info *shinfo;
265 struct sk_buff *skb;
266 unsigned int size = frag_size ? : ksize(data);
267
268 skb = kmem_cache_alloc(skbuff_head_cache, GFP_ATOMIC);
269 if (!skb)
270 return NULL;
271
272 size -= SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
273
274 memset(skb, 0, offsetof(struct sk_buff, tail));
275 skb->truesize = SKB_TRUESIZE(size);
276 skb->head_frag = frag_size != 0;
277 atomic_set(&skb->users, 1);
278 skb->head = data;
279 skb->data = data;
280 skb_reset_tail_pointer(skb);
281 skb->end = skb->tail + size;
282#ifdef NET_SKBUFF_DATA_USES_OFFSET
283 skb->mac_header = ~0U;
284#endif
285
286 /* make sure we initialize shinfo sequentially */
287 shinfo = skb_shinfo(skb);
288 memset(shinfo, 0, offsetof(struct skb_shared_info, dataref));
289 atomic_set(&shinfo->dataref, 1);
290 kmemcheck_annotate_variable(shinfo->destructor_arg);
291
292 return skb;
293}
294EXPORT_SYMBOL(build_skb);
295
296struct netdev_alloc_cache {
297 struct page *page;
298 unsigned int offset;
299};
300static DEFINE_PER_CPU(struct netdev_alloc_cache, netdev_alloc_cache);
301
302/**
303 * netdev_alloc_frag - allocate a page fragment
304 * @fragsz: fragment size
305 *
306 * Allocates a frag from a page for receive buffer.
307 * Uses GFP_ATOMIC allocations.
308 */
309void *netdev_alloc_frag(unsigned int fragsz)
310{
311 struct netdev_alloc_cache *nc;
312 void *data = NULL;
313 unsigned long flags;
314
315 local_irq_save(flags);
316 nc = &__get_cpu_var(netdev_alloc_cache);
317 if (unlikely(!nc->page)) {
318refill:
319 nc->page = alloc_page(GFP_ATOMIC | __GFP_COLD);
320 nc->offset = 0;
321 }
322 if (likely(nc->page)) {
323 if (nc->offset + fragsz > PAGE_SIZE) {
324 put_page(nc->page);
325 goto refill;
326 }
327 data = page_address(nc->page) + nc->offset;
328 nc->offset += fragsz;
329 get_page(nc->page);
330 }
331 local_irq_restore(flags);
332 return data;
333}
334EXPORT_SYMBOL(netdev_alloc_frag);
335
336/**
337 * __netdev_alloc_skb - allocate an skbuff for rx on a specific device
338 * @dev: network device to receive on
339 * @length: length to allocate
340 * @gfp_mask: get_free_pages mask, passed to alloc_skb
341 *
342 * Allocate a new &sk_buff and assign it a usage count of one. The
343 * buffer has unspecified headroom built in. Users should allocate
344 * the headroom they think they need without accounting for the
345 * built in space. The built in space is used for optimisations.
346 *
347 * %NULL is returned if there is no free memory.
348 */
349struct sk_buff *__netdev_alloc_skb(struct net_device *dev,
350 unsigned int length, gfp_t gfp_mask)
351{
352 struct sk_buff *skb = NULL;
353 unsigned int fragsz = SKB_DATA_ALIGN(length + NET_SKB_PAD) +
354 SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
355
356 if (fragsz <= PAGE_SIZE && !(gfp_mask & (__GFP_WAIT | GFP_DMA))) {
357 void *data = netdev_alloc_frag(fragsz);
358
359 if (likely(data)) {
360 skb = build_skb(data, fragsz);
361 if (unlikely(!skb))
362 put_page(virt_to_head_page(data));
363 }
364 } else {
365 skb = __alloc_skb(length + NET_SKB_PAD, gfp_mask, 0, NUMA_NO_NODE);
366 }
367 if (likely(skb)) {
368 skb_reserve(skb, NET_SKB_PAD);
369 skb->dev = dev;
370 }
371 return skb;
372}
373EXPORT_SYMBOL(__netdev_alloc_skb);
374
375void skb_add_rx_frag(struct sk_buff *skb, int i, struct page *page, int off,
376 int size, unsigned int truesize)
377{
378 skb_fill_page_desc(skb, i, page, off, size);
379 skb->len += size;
380 skb->data_len += size;
381 skb->truesize += truesize;
382}
383EXPORT_SYMBOL(skb_add_rx_frag);
384
385static void skb_drop_list(struct sk_buff **listp)
386{
387 struct sk_buff *list = *listp;
388
389 *listp = NULL;
390
391 do {
392 struct sk_buff *this = list;
393 list = list->next;
394 kfree_skb(this);
395 } while (list);
396}
397
398static inline void skb_drop_fraglist(struct sk_buff *skb)
399{
400 skb_drop_list(&skb_shinfo(skb)->frag_list);
401}
402
403static void skb_clone_fraglist(struct sk_buff *skb)
404{
405 struct sk_buff *list;
406
407 skb_walk_frags(skb, list)
408 skb_get(list);
409}
410
411static void skb_free_head(struct sk_buff *skb)
412{
413 if (skb->head_frag)
414 put_page(virt_to_head_page(skb->head));
415 else
416 kfree(skb->head);
417}
418
419static void skb_release_data(struct sk_buff *skb)
420{
421 if (!skb->cloned ||
422 !atomic_sub_return(skb->nohdr ? (1 << SKB_DATAREF_SHIFT) + 1 : 1,
423 &skb_shinfo(skb)->dataref)) {
424 if (skb_shinfo(skb)->nr_frags) {
425 int i;
426 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
427 skb_frag_unref(skb, i);
428 }
429
430 /*
431 * If skb buf is from userspace, we need to notify the caller
432 * the lower device DMA has done;
433 */
434 if (skb_shinfo(skb)->tx_flags & SKBTX_DEV_ZEROCOPY) {
435 struct ubuf_info *uarg;
436
437 uarg = skb_shinfo(skb)->destructor_arg;
438 if (uarg->callback)
439 uarg->callback(uarg);
440 }
441
442 if (skb_has_frag_list(skb))
443 skb_drop_fraglist(skb);
444
445 skb_free_head(skb);
446 }
447}
448
449/*
450 * Free an skbuff by memory without cleaning the state.
451 */
452static void kfree_skbmem(struct sk_buff *skb)
453{
454 struct sk_buff *other;
455 atomic_t *fclone_ref;
456
457 switch (skb->fclone) {
458 case SKB_FCLONE_UNAVAILABLE:
459 kmem_cache_free(skbuff_head_cache, skb);
460 break;
461
462 case SKB_FCLONE_ORIG:
463 fclone_ref = (atomic_t *) (skb + 2);
464 if (atomic_dec_and_test(fclone_ref))
465 kmem_cache_free(skbuff_fclone_cache, skb);
466 break;
467
468 case SKB_FCLONE_CLONE:
469 fclone_ref = (atomic_t *) (skb + 1);
470 other = skb - 1;
471
472 /* The clone portion is available for
473 * fast-cloning again.
474 */
475 skb->fclone = SKB_FCLONE_UNAVAILABLE;
476
477 if (atomic_dec_and_test(fclone_ref))
478 kmem_cache_free(skbuff_fclone_cache, other);
479 break;
480 }
481}
482
483static void skb_release_head_state(struct sk_buff *skb)
484{
485 skb_dst_drop(skb);
486#ifdef CONFIG_XFRM
487 secpath_put(skb->sp);
488#endif
489 if (skb->destructor) {
490 WARN_ON(in_irq());
491 skb->destructor(skb);
492 }
493#if IS_ENABLED(CONFIG_NF_CONNTRACK)
494 nf_conntrack_put(skb->nfct);
495#endif
496#ifdef NET_SKBUFF_NF_DEFRAG_NEEDED
497 nf_conntrack_put_reasm(skb->nfct_reasm);
498#endif
499#ifdef CONFIG_BRIDGE_NETFILTER
500 nf_bridge_put(skb->nf_bridge);
501#endif
502/* XXX: IS this still necessary? - JHS */
503#ifdef CONFIG_NET_SCHED
504 skb->tc_index = 0;
505#ifdef CONFIG_NET_CLS_ACT
506 skb->tc_verd = 0;
507#endif
508#endif
509}
510
511/* Free everything but the sk_buff shell. */
512static void skb_release_all(struct sk_buff *skb)
513{
514 skb_release_head_state(skb);
515 skb_release_data(skb);
516}
517
518/**
519 * __kfree_skb - private function
520 * @skb: buffer
521 *
522 * Free an sk_buff. Release anything attached to the buffer.
523 * Clean the state. This is an internal helper function. Users should
524 * always call kfree_skb
525 */
526
527void __kfree_skb(struct sk_buff *skb)
528{
529 skb_release_all(skb);
530 kfree_skbmem(skb);
531}
532EXPORT_SYMBOL(__kfree_skb);
533
534/**
535 * kfree_skb - free an sk_buff
536 * @skb: buffer to free
537 *
538 * Drop a reference to the buffer and free it if the usage count has
539 * hit zero.
540 */
541void kfree_skb(struct sk_buff *skb)
542{
543 if (unlikely(!skb))
544 return;
545 if (likely(atomic_read(&skb->users) == 1))
546 smp_rmb();
547 else if (likely(!atomic_dec_and_test(&skb->users)))
548 return;
549 trace_kfree_skb(skb, __builtin_return_address(0));
550 __kfree_skb(skb);
551}
552EXPORT_SYMBOL(kfree_skb);
553
554/**
555 * consume_skb - free an skbuff
556 * @skb: buffer to free
557 *
558 * Drop a ref to the buffer and free it if the usage count has hit zero
559 * Functions identically to kfree_skb, but kfree_skb assumes that the frame
560 * is being dropped after a failure and notes that
561 */
562void consume_skb(struct sk_buff *skb)
563{
564 if (unlikely(!skb))
565 return;
566 if (likely(atomic_read(&skb->users) == 1))
567 smp_rmb();
568 else if (likely(!atomic_dec_and_test(&skb->users)))
569 return;
570 trace_consume_skb(skb);
571 __kfree_skb(skb);
572}
573EXPORT_SYMBOL(consume_skb);
574
575/**
576 * skb_recycle - clean up an skb for reuse
577 * @skb: buffer
578 *
579 * Recycles the skb to be reused as a receive buffer. This
580 * function does any necessary reference count dropping, and
581 * cleans up the skbuff as if it just came from __alloc_skb().
582 */
583void skb_recycle(struct sk_buff *skb)
584{
585 struct skb_shared_info *shinfo;
586
587 skb_release_head_state(skb);
588
589 shinfo = skb_shinfo(skb);
590 memset(shinfo, 0, offsetof(struct skb_shared_info, dataref));
591 atomic_set(&shinfo->dataref, 1);
592
593 memset(skb, 0, offsetof(struct sk_buff, tail));
594 skb->data = skb->head + NET_SKB_PAD;
595 skb_reset_tail_pointer(skb);
596}
597EXPORT_SYMBOL(skb_recycle);
598
599/**
600 * skb_recycle_check - check if skb can be reused for receive
601 * @skb: buffer
602 * @skb_size: minimum receive buffer size
603 *
604 * Checks that the skb passed in is not shared or cloned, and
605 * that it is linear and its head portion at least as large as
606 * skb_size so that it can be recycled as a receive buffer.
607 * If these conditions are met, this function does any necessary
608 * reference count dropping and cleans up the skbuff as if it
609 * just came from __alloc_skb().
610 */
611bool skb_recycle_check(struct sk_buff *skb, int skb_size)
612{
613 if (!skb_is_recycleable(skb, skb_size))
614 return false;
615
616 skb_recycle(skb);
617
618 return true;
619}
620EXPORT_SYMBOL(skb_recycle_check);
621
622static void __copy_skb_header(struct sk_buff *new, const struct sk_buff *old)
623{
624 new->tstamp = old->tstamp;
625 new->dev = old->dev;
626 new->transport_header = old->transport_header;
627 new->network_header = old->network_header;
628 new->mac_header = old->mac_header;
629 skb_dst_copy(new, old);
630 new->rxhash = old->rxhash;
631 new->ooo_okay = old->ooo_okay;
632 new->l4_rxhash = old->l4_rxhash;
633 new->no_fcs = old->no_fcs;
634#ifdef CONFIG_XFRM
635 new->sp = secpath_get(old->sp);
636#endif
637 memcpy(new->cb, old->cb, sizeof(old->cb));
638 new->csum = old->csum;
639 new->local_df = old->local_df;
640 new->pkt_type = old->pkt_type;
641 new->ip_summed = old->ip_summed;
642 skb_copy_queue_mapping(new, old);
643 new->priority = old->priority;
644#if IS_ENABLED(CONFIG_IP_VS)
645 new->ipvs_property = old->ipvs_property;
646#endif
647 new->protocol = old->protocol;
648 new->mark = old->mark;
649 new->skb_iif = old->skb_iif;
650 __nf_copy(new, old);
651#if IS_ENABLED(CONFIG_NETFILTER_XT_TARGET_TRACE)
652 new->nf_trace = old->nf_trace;
653#endif
654#ifdef CONFIG_NET_SCHED
655 new->tc_index = old->tc_index;
656#ifdef CONFIG_NET_CLS_ACT
657 new->tc_verd = old->tc_verd;
658#endif
659#endif
660 new->vlan_tci = old->vlan_tci;
661
662 skb_copy_secmark(new, old);
663}
664
665/*
666 * You should not add any new code to this function. Add it to
667 * __copy_skb_header above instead.
668 */
669static struct sk_buff *__skb_clone(struct sk_buff *n, struct sk_buff *skb)
670{
671#define C(x) n->x = skb->x
672
673 n->next = n->prev = NULL;
674 n->sk = NULL;
675 __copy_skb_header(n, skb);
676
677 C(len);
678 C(data_len);
679 C(mac_len);
680 n->hdr_len = skb->nohdr ? skb_headroom(skb) : skb->hdr_len;
681 n->cloned = 1;
682 n->nohdr = 0;
683 n->destructor = NULL;
684 C(tail);
685 C(end);
686 C(head);
687 C(head_frag);
688 C(data);
689 C(truesize);
690 atomic_set(&n->users, 1);
691
692 atomic_inc(&(skb_shinfo(skb)->dataref));
693 skb->cloned = 1;
694
695 return n;
696#undef C
697}
698
699/**
700 * skb_morph - morph one skb into another
701 * @dst: the skb to receive the contents
702 * @src: the skb to supply the contents
703 *
704 * This is identical to skb_clone except that the target skb is
705 * supplied by the user.
706 *
707 * The target skb is returned upon exit.
708 */
709struct sk_buff *skb_morph(struct sk_buff *dst, struct sk_buff *src)
710{
711 skb_release_all(dst);
712 return __skb_clone(dst, src);
713}
714EXPORT_SYMBOL_GPL(skb_morph);
715
716/* skb_copy_ubufs - copy userspace skb frags buffers to kernel
717 * @skb: the skb to modify
718 * @gfp_mask: allocation priority
719 *
720 * This must be called on SKBTX_DEV_ZEROCOPY skb.
721 * It will copy all frags into kernel and drop the reference
722 * to userspace pages.
723 *
724 * If this function is called from an interrupt gfp_mask() must be
725 * %GFP_ATOMIC.
726 *
727 * Returns 0 on success or a negative error code on failure
728 * to allocate kernel memory to copy to.
729 */
730int skb_copy_ubufs(struct sk_buff *skb, gfp_t gfp_mask)
731{
732 int i;
733 int num_frags = skb_shinfo(skb)->nr_frags;
734 struct page *page, *head = NULL;
735 struct ubuf_info *uarg = skb_shinfo(skb)->destructor_arg;
736
737 for (i = 0; i < num_frags; i++) {
738 u8 *vaddr;
739 skb_frag_t *f = &skb_shinfo(skb)->frags[i];
740
741 page = alloc_page(GFP_ATOMIC);
742 if (!page) {
743 while (head) {
744 struct page *next = (struct page *)head->private;
745 put_page(head);
746 head = next;
747 }
748 return -ENOMEM;
749 }
750 vaddr = kmap_atomic(skb_frag_page(f));
751 memcpy(page_address(page),
752 vaddr + f->page_offset, skb_frag_size(f));
753 kunmap_atomic(vaddr);
754 page->private = (unsigned long)head;
755 head = page;
756 }
757
758 /* skb frags release userspace buffers */
759 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
760 skb_frag_unref(skb, i);
761
762 uarg->callback(uarg);
763
764 /* skb frags point to kernel buffers */
765 for (i = skb_shinfo(skb)->nr_frags; i > 0; i--) {
766 __skb_fill_page_desc(skb, i-1, head, 0,
767 skb_shinfo(skb)->frags[i - 1].size);
768 head = (struct page *)head->private;
769 }
770
771 skb_shinfo(skb)->tx_flags &= ~SKBTX_DEV_ZEROCOPY;
772 return 0;
773}
774
775
776/**
777 * skb_clone - duplicate an sk_buff
778 * @skb: buffer to clone
779 * @gfp_mask: allocation priority
780 *
781 * Duplicate an &sk_buff. The new one is not owned by a socket. Both
782 * copies share the same packet data but not structure. The new
783 * buffer has a reference count of 1. If the allocation fails the
784 * function returns %NULL otherwise the new buffer is returned.
785 *
786 * If this function is called from an interrupt gfp_mask() must be
787 * %GFP_ATOMIC.
788 */
789
790struct sk_buff *skb_clone(struct sk_buff *skb, gfp_t gfp_mask)
791{
792 struct sk_buff *n;
793
794 if (skb_shinfo(skb)->tx_flags & SKBTX_DEV_ZEROCOPY) {
795 if (skb_copy_ubufs(skb, gfp_mask))
796 return NULL;
797 }
798
799 n = skb + 1;
800 if (skb->fclone == SKB_FCLONE_ORIG &&
801 n->fclone == SKB_FCLONE_UNAVAILABLE) {
802 atomic_t *fclone_ref = (atomic_t *) (n + 1);
803 n->fclone = SKB_FCLONE_CLONE;
804 atomic_inc(fclone_ref);
805 } else {
806 n = kmem_cache_alloc(skbuff_head_cache, gfp_mask);
807 if (!n)
808 return NULL;
809
810 kmemcheck_annotate_bitfield(n, flags1);
811 kmemcheck_annotate_bitfield(n, flags2);
812 n->fclone = SKB_FCLONE_UNAVAILABLE;
813 }
814
815 return __skb_clone(n, skb);
816}
817EXPORT_SYMBOL(skb_clone);
818
819static void copy_skb_header(struct sk_buff *new, const struct sk_buff *old)
820{
821#ifndef NET_SKBUFF_DATA_USES_OFFSET
822 /*
823 * Shift between the two data areas in bytes
824 */
825 unsigned long offset = new->data - old->data;
826#endif
827
828 __copy_skb_header(new, old);
829
830#ifndef NET_SKBUFF_DATA_USES_OFFSET
831 /* {transport,network,mac}_header are relative to skb->head */
832 new->transport_header += offset;
833 new->network_header += offset;
834 if (skb_mac_header_was_set(new))
835 new->mac_header += offset;
836#endif
837 skb_shinfo(new)->gso_size = skb_shinfo(old)->gso_size;
838 skb_shinfo(new)->gso_segs = skb_shinfo(old)->gso_segs;
839 skb_shinfo(new)->gso_type = skb_shinfo(old)->gso_type;
840}
841
842/**
843 * skb_copy - create private copy of an sk_buff
844 * @skb: buffer to copy
845 * @gfp_mask: allocation priority
846 *
847 * Make a copy of both an &sk_buff and its data. This is used when the
848 * caller wishes to modify the data and needs a private copy of the
849 * data to alter. Returns %NULL on failure or the pointer to the buffer
850 * on success. The returned buffer has a reference count of 1.
851 *
852 * As by-product this function converts non-linear &sk_buff to linear
853 * one, so that &sk_buff becomes completely private and caller is allowed
854 * to modify all the data of returned buffer. This means that this
855 * function is not recommended for use in circumstances when only
856 * header is going to be modified. Use pskb_copy() instead.
857 */
858
859struct sk_buff *skb_copy(const struct sk_buff *skb, gfp_t gfp_mask)
860{
861 int headerlen = skb_headroom(skb);
862 unsigned int size = skb_end_offset(skb) + skb->data_len;
863 struct sk_buff *n = alloc_skb(size, gfp_mask);
864
865 if (!n)
866 return NULL;
867
868 /* Set the data pointer */
869 skb_reserve(n, headerlen);
870 /* Set the tail pointer and length */
871 skb_put(n, skb->len);
872
873 if (skb_copy_bits(skb, -headerlen, n->head, headerlen + skb->len))
874 BUG();
875
876 copy_skb_header(n, skb);
877 return n;
878}
879EXPORT_SYMBOL(skb_copy);
880
881/**
882 * __pskb_copy - create copy of an sk_buff with private head.
883 * @skb: buffer to copy
884 * @headroom: headroom of new skb
885 * @gfp_mask: allocation priority
886 *
887 * Make a copy of both an &sk_buff and part of its data, located
888 * in header. Fragmented data remain shared. This is used when
889 * the caller wishes to modify only header of &sk_buff and needs
890 * private copy of the header to alter. Returns %NULL on failure
891 * or the pointer to the buffer on success.
892 * The returned buffer has a reference count of 1.
893 */
894
895struct sk_buff *__pskb_copy(struct sk_buff *skb, int headroom, gfp_t gfp_mask)
896{
897 unsigned int size = skb_headlen(skb) + headroom;
898 struct sk_buff *n = alloc_skb(size, gfp_mask);
899
900 if (!n)
901 goto out;
902
903 /* Set the data pointer */
904 skb_reserve(n, headroom);
905 /* Set the tail pointer and length */
906 skb_put(n, skb_headlen(skb));
907 /* Copy the bytes */
908 skb_copy_from_linear_data(skb, n->data, n->len);
909
910 n->truesize += skb->data_len;
911 n->data_len = skb->data_len;
912 n->len = skb->len;
913
914 if (skb_shinfo(skb)->nr_frags) {
915 int i;
916
917 if (skb_shinfo(skb)->tx_flags & SKBTX_DEV_ZEROCOPY) {
918 if (skb_copy_ubufs(skb, gfp_mask)) {
919 kfree_skb(n);
920 n = NULL;
921 goto out;
922 }
923 }
924 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
925 skb_shinfo(n)->frags[i] = skb_shinfo(skb)->frags[i];
926 skb_frag_ref(skb, i);
927 }
928 skb_shinfo(n)->nr_frags = i;
929 }
930
931 if (skb_has_frag_list(skb)) {
932 skb_shinfo(n)->frag_list = skb_shinfo(skb)->frag_list;
933 skb_clone_fraglist(n);
934 }
935
936 copy_skb_header(n, skb);
937out:
938 return n;
939}
940EXPORT_SYMBOL(__pskb_copy);
941
942/**
943 * pskb_expand_head - reallocate header of &sk_buff
944 * @skb: buffer to reallocate
945 * @nhead: room to add at head
946 * @ntail: room to add at tail
947 * @gfp_mask: allocation priority
948 *
949 * Expands (or creates identical copy, if &nhead and &ntail are zero)
950 * header of skb. &sk_buff itself is not changed. &sk_buff MUST have
951 * reference count of 1. Returns zero in the case of success or error,
952 * if expansion failed. In the last case, &sk_buff is not changed.
953 *
954 * All the pointers pointing into skb header may change and must be
955 * reloaded after call to this function.
956 */
957
958int pskb_expand_head(struct sk_buff *skb, int nhead, int ntail,
959 gfp_t gfp_mask)
960{
961 int i;
962 u8 *data;
963 int size = nhead + skb_end_offset(skb) + ntail;
964 long off;
965
966 BUG_ON(nhead < 0);
967
968 if (skb_shared(skb))
969 BUG();
970
971 size = SKB_DATA_ALIGN(size);
972
973 data = kmalloc(size + SKB_DATA_ALIGN(sizeof(struct skb_shared_info)),
974 gfp_mask);
975 if (!data)
976 goto nodata;
977 size = SKB_WITH_OVERHEAD(ksize(data));
978
979 /* Copy only real data... and, alas, header. This should be
980 * optimized for the cases when header is void.
981 */
982 memcpy(data + nhead, skb->head, skb_tail_pointer(skb) - skb->head);
983
984 memcpy((struct skb_shared_info *)(data + size),
985 skb_shinfo(skb),
986 offsetof(struct skb_shared_info, frags[skb_shinfo(skb)->nr_frags]));
987
988 /*
989 * if shinfo is shared we must drop the old head gracefully, but if it
990 * is not we can just drop the old head and let the existing refcount
991 * be since all we did is relocate the values
992 */
993 if (skb_cloned(skb)) {
994 /* copy this zero copy skb frags */
995 if (skb_shinfo(skb)->tx_flags & SKBTX_DEV_ZEROCOPY) {
996 if (skb_copy_ubufs(skb, gfp_mask))
997 goto nofrags;
998 }
999 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
1000 skb_frag_ref(skb, i);
1001
1002 if (skb_has_frag_list(skb))
1003 skb_clone_fraglist(skb);
1004
1005 skb_release_data(skb);
1006 } else {
1007 skb_free_head(skb);
1008 }
1009 off = (data + nhead) - skb->head;
1010
1011 skb->head = data;
1012 skb->head_frag = 0;
1013 skb->data += off;
1014#ifdef NET_SKBUFF_DATA_USES_OFFSET
1015 skb->end = size;
1016 off = nhead;
1017#else
1018 skb->end = skb->head + size;
1019#endif
1020 /* {transport,network,mac}_header and tail are relative to skb->head */
1021 skb->tail += off;
1022 skb->transport_header += off;
1023 skb->network_header += off;
1024 if (skb_mac_header_was_set(skb))
1025 skb->mac_header += off;
1026 /* Only adjust this if it actually is csum_start rather than csum */
1027 if (skb->ip_summed == CHECKSUM_PARTIAL)
1028 skb->csum_start += nhead;
1029 skb->cloned = 0;
1030 skb->hdr_len = 0;
1031 skb->nohdr = 0;
1032 atomic_set(&skb_shinfo(skb)->dataref, 1);
1033 return 0;
1034
1035nofrags:
1036 kfree(data);
1037nodata:
1038 return -ENOMEM;
1039}
1040EXPORT_SYMBOL(pskb_expand_head);
1041
1042/* Make private copy of skb with writable head and some headroom */
1043
1044struct sk_buff *skb_realloc_headroom(struct sk_buff *skb, unsigned int headroom)
1045{
1046 struct sk_buff *skb2;
1047 int delta = headroom - skb_headroom(skb);
1048
1049 if (delta <= 0)
1050 skb2 = pskb_copy(skb, GFP_ATOMIC);
1051 else {
1052 skb2 = skb_clone(skb, GFP_ATOMIC);
1053 if (skb2 && pskb_expand_head(skb2, SKB_DATA_ALIGN(delta), 0,
1054 GFP_ATOMIC)) {
1055 kfree_skb(skb2);
1056 skb2 = NULL;
1057 }
1058 }
1059 return skb2;
1060}
1061EXPORT_SYMBOL(skb_realloc_headroom);
1062
1063/**
1064 * skb_copy_expand - copy and expand sk_buff
1065 * @skb: buffer to copy
1066 * @newheadroom: new free bytes at head
1067 * @newtailroom: new free bytes at tail
1068 * @gfp_mask: allocation priority
1069 *
1070 * Make a copy of both an &sk_buff and its data and while doing so
1071 * allocate additional space.
1072 *
1073 * This is used when the caller wishes to modify the data and needs a
1074 * private copy of the data to alter as well as more space for new fields.
1075 * Returns %NULL on failure or the pointer to the buffer
1076 * on success. The returned buffer has a reference count of 1.
1077 *
1078 * You must pass %GFP_ATOMIC as the allocation priority if this function
1079 * is called from an interrupt.
1080 */
1081struct sk_buff *skb_copy_expand(const struct sk_buff *skb,
1082 int newheadroom, int newtailroom,
1083 gfp_t gfp_mask)
1084{
1085 /*
1086 * Allocate the copy buffer
1087 */
1088 struct sk_buff *n = alloc_skb(newheadroom + skb->len + newtailroom,
1089 gfp_mask);
1090 int oldheadroom = skb_headroom(skb);
1091 int head_copy_len, head_copy_off;
1092 int off;
1093
1094 if (!n)
1095 return NULL;
1096
1097 skb_reserve(n, newheadroom);
1098
1099 /* Set the tail pointer and length */
1100 skb_put(n, skb->len);
1101
1102 head_copy_len = oldheadroom;
1103 head_copy_off = 0;
1104 if (newheadroom <= head_copy_len)
1105 head_copy_len = newheadroom;
1106 else
1107 head_copy_off = newheadroom - head_copy_len;
1108
1109 /* Copy the linear header and data. */
1110 if (skb_copy_bits(skb, -head_copy_len, n->head + head_copy_off,
1111 skb->len + head_copy_len))
1112 BUG();
1113
1114 copy_skb_header(n, skb);
1115
1116 off = newheadroom - oldheadroom;
1117 if (n->ip_summed == CHECKSUM_PARTIAL)
1118 n->csum_start += off;
1119#ifdef NET_SKBUFF_DATA_USES_OFFSET
1120 n->transport_header += off;
1121 n->network_header += off;
1122 if (skb_mac_header_was_set(skb))
1123 n->mac_header += off;
1124#endif
1125
1126 return n;
1127}
1128EXPORT_SYMBOL(skb_copy_expand);
1129
1130/**
1131 * skb_pad - zero pad the tail of an skb
1132 * @skb: buffer to pad
1133 * @pad: space to pad
1134 *
1135 * Ensure that a buffer is followed by a padding area that is zero
1136 * filled. Used by network drivers which may DMA or transfer data
1137 * beyond the buffer end onto the wire.
1138 *
1139 * May return error in out of memory cases. The skb is freed on error.
1140 */
1141
1142int skb_pad(struct sk_buff *skb, int pad)
1143{
1144 int err;
1145 int ntail;
1146
1147 /* If the skbuff is non linear tailroom is always zero.. */
1148 if (!skb_cloned(skb) && skb_tailroom(skb) >= pad) {
1149 memset(skb->data+skb->len, 0, pad);
1150 return 0;
1151 }
1152
1153 ntail = skb->data_len + pad - (skb->end - skb->tail);
1154 if (likely(skb_cloned(skb) || ntail > 0)) {
1155 err = pskb_expand_head(skb, 0, ntail, GFP_ATOMIC);
1156 if (unlikely(err))
1157 goto free_skb;
1158 }
1159
1160 /* FIXME: The use of this function with non-linear skb's really needs
1161 * to be audited.
1162 */
1163 err = skb_linearize(skb);
1164 if (unlikely(err))
1165 goto free_skb;
1166
1167 memset(skb->data + skb->len, 0, pad);
1168 return 0;
1169
1170free_skb:
1171 kfree_skb(skb);
1172 return err;
1173}
1174EXPORT_SYMBOL(skb_pad);
1175
1176/**
1177 * skb_put - add data to a buffer
1178 * @skb: buffer to use
1179 * @len: amount of data to add
1180 *
1181 * This function extends the used data area of the buffer. If this would
1182 * exceed the total buffer size the kernel will panic. A pointer to the
1183 * first byte of the extra data is returned.
1184 */
1185unsigned char *skb_put(struct sk_buff *skb, unsigned int len)
1186{
1187 unsigned char *tmp = skb_tail_pointer(skb);
1188 SKB_LINEAR_ASSERT(skb);
1189 skb->tail += len;
1190 skb->len += len;
1191 if (unlikely(skb->tail > skb->end))
1192 skb_over_panic(skb, len, __builtin_return_address(0));
1193 return tmp;
1194}
1195EXPORT_SYMBOL(skb_put);
1196
1197/**
1198 * skb_push - add data to the start of a buffer
1199 * @skb: buffer to use
1200 * @len: amount of data to add
1201 *
1202 * This function extends the used data area of the buffer at the buffer
1203 * start. If this would exceed the total buffer headroom the kernel will
1204 * panic. A pointer to the first byte of the extra data is returned.
1205 */
1206unsigned char *skb_push(struct sk_buff *skb, unsigned int len)
1207{
1208 skb->data -= len;
1209 skb->len += len;
1210 if (unlikely(skb->data<skb->head))
1211 skb_under_panic(skb, len, __builtin_return_address(0));
1212 return skb->data;
1213}
1214EXPORT_SYMBOL(skb_push);
1215
1216/**
1217 * skb_pull - remove data from the start of a buffer
1218 * @skb: buffer to use
1219 * @len: amount of data to remove
1220 *
1221 * This function removes data from the start of a buffer, returning
1222 * the memory to the headroom. A pointer to the next data in the buffer
1223 * is returned. Once the data has been pulled future pushes will overwrite
1224 * the old data.
1225 */
1226unsigned char *skb_pull(struct sk_buff *skb, unsigned int len)
1227{
1228 return skb_pull_inline(skb, len);
1229}
1230EXPORT_SYMBOL(skb_pull);
1231
1232/**
1233 * skb_trim - remove end from a buffer
1234 * @skb: buffer to alter
1235 * @len: new length
1236 *
1237 * Cut the length of a buffer down by removing data from the tail. If
1238 * the buffer is already under the length specified it is not modified.
1239 * The skb must be linear.
1240 */
1241void skb_trim(struct sk_buff *skb, unsigned int len)
1242{
1243 if (skb->len > len)
1244 __skb_trim(skb, len);
1245}
1246EXPORT_SYMBOL(skb_trim);
1247
1248/* Trims skb to length len. It can change skb pointers.
1249 */
1250
1251int ___pskb_trim(struct sk_buff *skb, unsigned int len)
1252{
1253 struct sk_buff **fragp;
1254 struct sk_buff *frag;
1255 int offset = skb_headlen(skb);
1256 int nfrags = skb_shinfo(skb)->nr_frags;
1257 int i;
1258 int err;
1259
1260 if (skb_cloned(skb) &&
1261 unlikely((err = pskb_expand_head(skb, 0, 0, GFP_ATOMIC))))
1262 return err;
1263
1264 i = 0;
1265 if (offset >= len)
1266 goto drop_pages;
1267
1268 for (; i < nfrags; i++) {
1269 int end = offset + skb_frag_size(&skb_shinfo(skb)->frags[i]);
1270
1271 if (end < len) {
1272 offset = end;
1273 continue;
1274 }
1275
1276 skb_frag_size_set(&skb_shinfo(skb)->frags[i++], len - offset);
1277
1278drop_pages:
1279 skb_shinfo(skb)->nr_frags = i;
1280
1281 for (; i < nfrags; i++)
1282 skb_frag_unref(skb, i);
1283
1284 if (skb_has_frag_list(skb))
1285 skb_drop_fraglist(skb);
1286 goto done;
1287 }
1288
1289 for (fragp = &skb_shinfo(skb)->frag_list; (frag = *fragp);
1290 fragp = &frag->next) {
1291 int end = offset + frag->len;
1292
1293 if (skb_shared(frag)) {
1294 struct sk_buff *nfrag;
1295
1296 nfrag = skb_clone(frag, GFP_ATOMIC);
1297 if (unlikely(!nfrag))
1298 return -ENOMEM;
1299
1300 nfrag->next = frag->next;
1301 consume_skb(frag);
1302 frag = nfrag;
1303 *fragp = frag;
1304 }
1305
1306 if (end < len) {
1307 offset = end;
1308 continue;
1309 }
1310
1311 if (end > len &&
1312 unlikely((err = pskb_trim(frag, len - offset))))
1313 return err;
1314
1315 if (frag->next)
1316 skb_drop_list(&frag->next);
1317 break;
1318 }
1319
1320done:
1321 if (len > skb_headlen(skb)) {
1322 skb->data_len -= skb->len - len;
1323 skb->len = len;
1324 } else {
1325 skb->len = len;
1326 skb->data_len = 0;
1327 skb_set_tail_pointer(skb, len);
1328 }
1329
1330 return 0;
1331}
1332EXPORT_SYMBOL(___pskb_trim);
1333
1334/**
1335 * __pskb_pull_tail - advance tail of skb header
1336 * @skb: buffer to reallocate
1337 * @delta: number of bytes to advance tail
1338 *
1339 * The function makes a sense only on a fragmented &sk_buff,
1340 * it expands header moving its tail forward and copying necessary
1341 * data from fragmented part.
1342 *
1343 * &sk_buff MUST have reference count of 1.
1344 *
1345 * Returns %NULL (and &sk_buff does not change) if pull failed
1346 * or value of new tail of skb in the case of success.
1347 *
1348 * All the pointers pointing into skb header may change and must be
1349 * reloaded after call to this function.
1350 */
1351
1352/* Moves tail of skb head forward, copying data from fragmented part,
1353 * when it is necessary.
1354 * 1. It may fail due to malloc failure.
1355 * 2. It may change skb pointers.
1356 *
1357 * It is pretty complicated. Luckily, it is called only in exceptional cases.
1358 */
1359unsigned char *__pskb_pull_tail(struct sk_buff *skb, int delta)
1360{
1361 /* If skb has not enough free space at tail, get new one
1362 * plus 128 bytes for future expansions. If we have enough
1363 * room at tail, reallocate without expansion only if skb is cloned.
1364 */
1365 int i, k, eat = (skb->tail + delta) - skb->end;
1366
1367 if (eat > 0 || skb_cloned(skb)) {
1368 if (pskb_expand_head(skb, 0, eat > 0 ? eat + 128 : 0,
1369 GFP_ATOMIC))
1370 return NULL;
1371 }
1372
1373 if (skb_copy_bits(skb, skb_headlen(skb), skb_tail_pointer(skb), delta))
1374 BUG();
1375
1376 /* Optimization: no fragments, no reasons to preestimate
1377 * size of pulled pages. Superb.
1378 */
1379 if (!skb_has_frag_list(skb))
1380 goto pull_pages;
1381
1382 /* Estimate size of pulled pages. */
1383 eat = delta;
1384 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
1385 int size = skb_frag_size(&skb_shinfo(skb)->frags[i]);
1386
1387 if (size >= eat)
1388 goto pull_pages;
1389 eat -= size;
1390 }
1391
1392 /* If we need update frag list, we are in troubles.
1393 * Certainly, it possible to add an offset to skb data,
1394 * but taking into account that pulling is expected to
1395 * be very rare operation, it is worth to fight against
1396 * further bloating skb head and crucify ourselves here instead.
1397 * Pure masohism, indeed. 8)8)
1398 */
1399 if (eat) {
1400 struct sk_buff *list = skb_shinfo(skb)->frag_list;
1401 struct sk_buff *clone = NULL;
1402 struct sk_buff *insp = NULL;
1403
1404 do {
1405 BUG_ON(!list);
1406
1407 if (list->len <= eat) {
1408 /* Eaten as whole. */
1409 eat -= list->len;
1410 list = list->next;
1411 insp = list;
1412 } else {
1413 /* Eaten partially. */
1414
1415 if (skb_shared(list)) {
1416 /* Sucks! We need to fork list. :-( */
1417 clone = skb_clone(list, GFP_ATOMIC);
1418 if (!clone)
1419 return NULL;
1420 insp = list->next;
1421 list = clone;
1422 } else {
1423 /* This may be pulled without
1424 * problems. */
1425 insp = list;
1426 }
1427 if (!pskb_pull(list, eat)) {
1428 kfree_skb(clone);
1429 return NULL;
1430 }
1431 break;
1432 }
1433 } while (eat);
1434
1435 /* Free pulled out fragments. */
1436 while ((list = skb_shinfo(skb)->frag_list) != insp) {
1437 skb_shinfo(skb)->frag_list = list->next;
1438 kfree_skb(list);
1439 }
1440 /* And insert new clone at head. */
1441 if (clone) {
1442 clone->next = list;
1443 skb_shinfo(skb)->frag_list = clone;
1444 }
1445 }
1446 /* Success! Now we may commit changes to skb data. */
1447
1448pull_pages:
1449 eat = delta;
1450 k = 0;
1451 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
1452 int size = skb_frag_size(&skb_shinfo(skb)->frags[i]);
1453
1454 if (size <= eat) {
1455 skb_frag_unref(skb, i);
1456 eat -= size;
1457 } else {
1458 skb_shinfo(skb)->frags[k] = skb_shinfo(skb)->frags[i];
1459 if (eat) {
1460 skb_shinfo(skb)->frags[k].page_offset += eat;
1461 skb_frag_size_sub(&skb_shinfo(skb)->frags[k], eat);
1462 eat = 0;
1463 }
1464 k++;
1465 }
1466 }
1467 skb_shinfo(skb)->nr_frags = k;
1468
1469 skb->tail += delta;
1470 skb->data_len -= delta;
1471
1472 return skb_tail_pointer(skb);
1473}
1474EXPORT_SYMBOL(__pskb_pull_tail);
1475
1476/**
1477 * skb_copy_bits - copy bits from skb to kernel buffer
1478 * @skb: source skb
1479 * @offset: offset in source
1480 * @to: destination buffer
1481 * @len: number of bytes to copy
1482 *
1483 * Copy the specified number of bytes from the source skb to the
1484 * destination buffer.
1485 *
1486 * CAUTION ! :
1487 * If its prototype is ever changed,
1488 * check arch/{*}/net/{*}.S files,
1489 * since it is called from BPF assembly code.
1490 */
1491int skb_copy_bits(const struct sk_buff *skb, int offset, void *to, int len)
1492{
1493 int start = skb_headlen(skb);
1494 struct sk_buff *frag_iter;
1495 int i, copy;
1496
1497 if (offset > (int)skb->len - len)
1498 goto fault;
1499
1500 /* Copy header. */
1501 if ((copy = start - offset) > 0) {
1502 if (copy > len)
1503 copy = len;
1504 skb_copy_from_linear_data_offset(skb, offset, to, copy);
1505 if ((len -= copy) == 0)
1506 return 0;
1507 offset += copy;
1508 to += copy;
1509 }
1510
1511 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
1512 int end;
1513 skb_frag_t *f = &skb_shinfo(skb)->frags[i];
1514
1515 WARN_ON(start > offset + len);
1516
1517 end = start + skb_frag_size(f);
1518 if ((copy = end - offset) > 0) {
1519 u8 *vaddr;
1520
1521 if (copy > len)
1522 copy = len;
1523
1524 vaddr = kmap_atomic(skb_frag_page(f));
1525 memcpy(to,
1526 vaddr + f->page_offset + offset - start,
1527 copy);
1528 kunmap_atomic(vaddr);
1529
1530 if ((len -= copy) == 0)
1531 return 0;
1532 offset += copy;
1533 to += copy;
1534 }
1535 start = end;
1536 }
1537
1538 skb_walk_frags(skb, frag_iter) {
1539 int end;
1540
1541 WARN_ON(start > offset + len);
1542
1543 end = start + frag_iter->len;
1544 if ((copy = end - offset) > 0) {
1545 if (copy > len)
1546 copy = len;
1547 if (skb_copy_bits(frag_iter, offset - start, to, copy))
1548 goto fault;
1549 if ((len -= copy) == 0)
1550 return 0;
1551 offset += copy;
1552 to += copy;
1553 }
1554 start = end;
1555 }
1556
1557 if (!len)
1558 return 0;
1559
1560fault:
1561 return -EFAULT;
1562}
1563EXPORT_SYMBOL(skb_copy_bits);
1564
1565/*
1566 * Callback from splice_to_pipe(), if we need to release some pages
1567 * at the end of the spd in case we error'ed out in filling the pipe.
1568 */
1569static void sock_spd_release(struct splice_pipe_desc *spd, unsigned int i)
1570{
1571 put_page(spd->pages[i]);
1572}
1573
1574static struct page *linear_to_page(struct page *page, unsigned int *len,
1575 unsigned int *offset,
1576 struct sk_buff *skb, struct sock *sk)
1577{
1578 struct page *p = sk->sk_sndmsg_page;
1579 unsigned int off;
1580
1581 if (!p) {
1582new_page:
1583 p = sk->sk_sndmsg_page = alloc_pages(sk->sk_allocation, 0);
1584 if (!p)
1585 return NULL;
1586
1587 off = sk->sk_sndmsg_off = 0;
1588 /* hold one ref to this page until it's full */
1589 } else {
1590 unsigned int mlen;
1591
1592 /* If we are the only user of the page, we can reset offset */
1593 if (page_count(p) == 1)
1594 sk->sk_sndmsg_off = 0;
1595 off = sk->sk_sndmsg_off;
1596 mlen = PAGE_SIZE - off;
1597 if (mlen < 64 && mlen < *len) {
1598 put_page(p);
1599 goto new_page;
1600 }
1601
1602 *len = min_t(unsigned int, *len, mlen);
1603 }
1604
1605 memcpy(page_address(p) + off, page_address(page) + *offset, *len);
1606 sk->sk_sndmsg_off += *len;
1607 *offset = off;
1608
1609 return p;
1610}
1611
1612static bool spd_can_coalesce(const struct splice_pipe_desc *spd,
1613 struct page *page,
1614 unsigned int offset)
1615{
1616 return spd->nr_pages &&
1617 spd->pages[spd->nr_pages - 1] == page &&
1618 (spd->partial[spd->nr_pages - 1].offset +
1619 spd->partial[spd->nr_pages - 1].len == offset);
1620}
1621
1622/*
1623 * Fill page/offset/length into spd, if it can hold more pages.
1624 */
1625static bool spd_fill_page(struct splice_pipe_desc *spd,
1626 struct pipe_inode_info *pipe, struct page *page,
1627 unsigned int *len, unsigned int offset,
1628 struct sk_buff *skb, bool linear,
1629 struct sock *sk)
1630{
1631 if (unlikely(spd->nr_pages == MAX_SKB_FRAGS))
1632 return true;
1633
1634 if (linear) {
1635 page = linear_to_page(page, len, &offset, skb, sk);
1636 if (!page)
1637 return true;
1638 }
1639 if (spd_can_coalesce(spd, page, offset)) {
1640 spd->partial[spd->nr_pages - 1].len += *len;
1641 return false;
1642 }
1643 get_page(page);
1644 spd->pages[spd->nr_pages] = page;
1645 spd->partial[spd->nr_pages].len = *len;
1646 spd->partial[spd->nr_pages].offset = offset;
1647 spd->nr_pages++;
1648
1649 return false;
1650}
1651
1652static inline void __segment_seek(struct page **page, unsigned int *poff,
1653 unsigned int *plen, unsigned int off)
1654{
1655 unsigned long n;
1656
1657 *poff += off;
1658 n = *poff / PAGE_SIZE;
1659 if (n)
1660 *page = nth_page(*page, n);
1661
1662 *poff = *poff % PAGE_SIZE;
1663 *plen -= off;
1664}
1665
1666static bool __splice_segment(struct page *page, unsigned int poff,
1667 unsigned int plen, unsigned int *off,
1668 unsigned int *len, struct sk_buff *skb,
1669 struct splice_pipe_desc *spd, bool linear,
1670 struct sock *sk,
1671 struct pipe_inode_info *pipe)
1672{
1673 if (!*len)
1674 return true;
1675
1676 /* skip this segment if already processed */
1677 if (*off >= plen) {
1678 *off -= plen;
1679 return false;
1680 }
1681
1682 /* ignore any bits we already processed */
1683 if (*off) {
1684 __segment_seek(&page, &poff, &plen, *off);
1685 *off = 0;
1686 }
1687
1688 do {
1689 unsigned int flen = min(*len, plen);
1690
1691 /* the linear region may spread across several pages */
1692 flen = min_t(unsigned int, flen, PAGE_SIZE - poff);
1693
1694 if (spd_fill_page(spd, pipe, page, &flen, poff, skb, linear, sk))
1695 return true;
1696
1697 __segment_seek(&page, &poff, &plen, flen);
1698 *len -= flen;
1699
1700 } while (*len && plen);
1701
1702 return false;
1703}
1704
1705/*
1706 * Map linear and fragment data from the skb to spd. It reports true if the
1707 * pipe is full or if we already spliced the requested length.
1708 */
1709static bool __skb_splice_bits(struct sk_buff *skb, struct pipe_inode_info *pipe,
1710 unsigned int *offset, unsigned int *len,
1711 struct splice_pipe_desc *spd, struct sock *sk)
1712{
1713 int seg;
1714
1715 /* map the linear part :
1716 * If skb->head_frag is set, this 'linear' part is backed by a
1717 * fragment, and if the head is not shared with any clones then
1718 * we can avoid a copy since we own the head portion of this page.
1719 */
1720 if (__splice_segment(virt_to_page(skb->data),
1721 (unsigned long) skb->data & (PAGE_SIZE - 1),
1722 skb_headlen(skb),
1723 offset, len, skb, spd,
1724 skb_head_is_locked(skb),
1725 sk, pipe))
1726 return true;
1727
1728 /*
1729 * then map the fragments
1730 */
1731 for (seg = 0; seg < skb_shinfo(skb)->nr_frags; seg++) {
1732 const skb_frag_t *f = &skb_shinfo(skb)->frags[seg];
1733
1734 if (__splice_segment(skb_frag_page(f),
1735 f->page_offset, skb_frag_size(f),
1736 offset, len, skb, spd, false, sk, pipe))
1737 return true;
1738 }
1739
1740 return false;
1741}
1742
1743/*
1744 * Map data from the skb to a pipe. Should handle both the linear part,
1745 * the fragments, and the frag list. It does NOT handle frag lists within
1746 * the frag list, if such a thing exists. We'd probably need to recurse to
1747 * handle that cleanly.
1748 */
1749int skb_splice_bits(struct sk_buff *skb, unsigned int offset,
1750 struct pipe_inode_info *pipe, unsigned int tlen,
1751 unsigned int flags)
1752{
1753 struct partial_page partial[MAX_SKB_FRAGS];
1754 struct page *pages[MAX_SKB_FRAGS];
1755 struct splice_pipe_desc spd = {
1756 .pages = pages,
1757 .partial = partial,
1758 .nr_pages_max = MAX_SKB_FRAGS,
1759 .flags = flags,
1760 .ops = &sock_pipe_buf_ops,
1761 .spd_release = sock_spd_release,
1762 };
1763 struct sk_buff *frag_iter;
1764 struct sock *sk = skb->sk;
1765 int ret = 0;
1766
1767 /*
1768 * __skb_splice_bits() only fails if the output has no room left,
1769 * so no point in going over the frag_list for the error case.
1770 */
1771 if (__skb_splice_bits(skb, pipe, &offset, &tlen, &spd, sk))
1772 goto done;
1773 else if (!tlen)
1774 goto done;
1775
1776 /*
1777 * now see if we have a frag_list to map
1778 */
1779 skb_walk_frags(skb, frag_iter) {
1780 if (!tlen)
1781 break;
1782 if (__skb_splice_bits(frag_iter, pipe, &offset, &tlen, &spd, sk))
1783 break;
1784 }
1785
1786done:
1787 if (spd.nr_pages) {
1788 /*
1789 * Drop the socket lock, otherwise we have reverse
1790 * locking dependencies between sk_lock and i_mutex
1791 * here as compared to sendfile(). We enter here
1792 * with the socket lock held, and splice_to_pipe() will
1793 * grab the pipe inode lock. For sendfile() emulation,
1794 * we call into ->sendpage() with the i_mutex lock held
1795 * and networking will grab the socket lock.
1796 */
1797 release_sock(sk);
1798 ret = splice_to_pipe(pipe, &spd);
1799 lock_sock(sk);
1800 }
1801
1802 return ret;
1803}
1804
1805/**
1806 * skb_store_bits - store bits from kernel buffer to skb
1807 * @skb: destination buffer
1808 * @offset: offset in destination
1809 * @from: source buffer
1810 * @len: number of bytes to copy
1811 *
1812 * Copy the specified number of bytes from the source buffer to the
1813 * destination skb. This function handles all the messy bits of
1814 * traversing fragment lists and such.
1815 */
1816
1817int skb_store_bits(struct sk_buff *skb, int offset, const void *from, int len)
1818{
1819 int start = skb_headlen(skb);
1820 struct sk_buff *frag_iter;
1821 int i, copy;
1822
1823 if (offset > (int)skb->len - len)
1824 goto fault;
1825
1826 if ((copy = start - offset) > 0) {
1827 if (copy > len)
1828 copy = len;
1829 skb_copy_to_linear_data_offset(skb, offset, from, copy);
1830 if ((len -= copy) == 0)
1831 return 0;
1832 offset += copy;
1833 from += copy;
1834 }
1835
1836 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
1837 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
1838 int end;
1839
1840 WARN_ON(start > offset + len);
1841
1842 end = start + skb_frag_size(frag);
1843 if ((copy = end - offset) > 0) {
1844 u8 *vaddr;
1845
1846 if (copy > len)
1847 copy = len;
1848
1849 vaddr = kmap_atomic(skb_frag_page(frag));
1850 memcpy(vaddr + frag->page_offset + offset - start,
1851 from, copy);
1852 kunmap_atomic(vaddr);
1853
1854 if ((len -= copy) == 0)
1855 return 0;
1856 offset += copy;
1857 from += copy;
1858 }
1859 start = end;
1860 }
1861
1862 skb_walk_frags(skb, frag_iter) {
1863 int end;
1864
1865 WARN_ON(start > offset + len);
1866
1867 end = start + frag_iter->len;
1868 if ((copy = end - offset) > 0) {
1869 if (copy > len)
1870 copy = len;
1871 if (skb_store_bits(frag_iter, offset - start,
1872 from, copy))
1873 goto fault;
1874 if ((len -= copy) == 0)
1875 return 0;
1876 offset += copy;
1877 from += copy;
1878 }
1879 start = end;
1880 }
1881 if (!len)
1882 return 0;
1883
1884fault:
1885 return -EFAULT;
1886}
1887EXPORT_SYMBOL(skb_store_bits);
1888
1889/* Checksum skb data. */
1890
1891__wsum skb_checksum(const struct sk_buff *skb, int offset,
1892 int len, __wsum csum)
1893{
1894 int start = skb_headlen(skb);
1895 int i, copy = start - offset;
1896 struct sk_buff *frag_iter;
1897 int pos = 0;
1898
1899 /* Checksum header. */
1900 if (copy > 0) {
1901 if (copy > len)
1902 copy = len;
1903 csum = csum_partial(skb->data + offset, copy, csum);
1904 if ((len -= copy) == 0)
1905 return csum;
1906 offset += copy;
1907 pos = copy;
1908 }
1909
1910 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
1911 int end;
1912 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
1913
1914 WARN_ON(start > offset + len);
1915
1916 end = start + skb_frag_size(frag);
1917 if ((copy = end - offset) > 0) {
1918 __wsum csum2;
1919 u8 *vaddr;
1920
1921 if (copy > len)
1922 copy = len;
1923 vaddr = kmap_atomic(skb_frag_page(frag));
1924 csum2 = csum_partial(vaddr + frag->page_offset +
1925 offset - start, copy, 0);
1926 kunmap_atomic(vaddr);
1927 csum = csum_block_add(csum, csum2, pos);
1928 if (!(len -= copy))
1929 return csum;
1930 offset += copy;
1931 pos += copy;
1932 }
1933 start = end;
1934 }
1935
1936 skb_walk_frags(skb, frag_iter) {
1937 int end;
1938
1939 WARN_ON(start > offset + len);
1940
1941 end = start + frag_iter->len;
1942 if ((copy = end - offset) > 0) {
1943 __wsum csum2;
1944 if (copy > len)
1945 copy = len;
1946 csum2 = skb_checksum(frag_iter, offset - start,
1947 copy, 0);
1948 csum = csum_block_add(csum, csum2, pos);
1949 if ((len -= copy) == 0)
1950 return csum;
1951 offset += copy;
1952 pos += copy;
1953 }
1954 start = end;
1955 }
1956 BUG_ON(len);
1957
1958 return csum;
1959}
1960EXPORT_SYMBOL(skb_checksum);
1961
1962/* Both of above in one bottle. */
1963
1964__wsum skb_copy_and_csum_bits(const struct sk_buff *skb, int offset,
1965 u8 *to, int len, __wsum csum)
1966{
1967 int start = skb_headlen(skb);
1968 int i, copy = start - offset;
1969 struct sk_buff *frag_iter;
1970 int pos = 0;
1971
1972 /* Copy header. */
1973 if (copy > 0) {
1974 if (copy > len)
1975 copy = len;
1976 csum = csum_partial_copy_nocheck(skb->data + offset, to,
1977 copy, csum);
1978 if ((len -= copy) == 0)
1979 return csum;
1980 offset += copy;
1981 to += copy;
1982 pos = copy;
1983 }
1984
1985 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
1986 int end;
1987
1988 WARN_ON(start > offset + len);
1989
1990 end = start + skb_frag_size(&skb_shinfo(skb)->frags[i]);
1991 if ((copy = end - offset) > 0) {
1992 __wsum csum2;
1993 u8 *vaddr;
1994 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
1995
1996 if (copy > len)
1997 copy = len;
1998 vaddr = kmap_atomic(skb_frag_page(frag));
1999 csum2 = csum_partial_copy_nocheck(vaddr +
2000 frag->page_offset +
2001 offset - start, to,
2002 copy, 0);
2003 kunmap_atomic(vaddr);
2004 csum = csum_block_add(csum, csum2, pos);
2005 if (!(len -= copy))
2006 return csum;
2007 offset += copy;
2008 to += copy;
2009 pos += copy;
2010 }
2011 start = end;
2012 }
2013
2014 skb_walk_frags(skb, frag_iter) {
2015 __wsum csum2;
2016 int end;
2017
2018 WARN_ON(start > offset + len);
2019
2020 end = start + frag_iter->len;
2021 if ((copy = end - offset) > 0) {
2022 if (copy > len)
2023 copy = len;
2024 csum2 = skb_copy_and_csum_bits(frag_iter,
2025 offset - start,
2026 to, copy, 0);
2027 csum = csum_block_add(csum, csum2, pos);
2028 if ((len -= copy) == 0)
2029 return csum;
2030 offset += copy;
2031 to += copy;
2032 pos += copy;
2033 }
2034 start = end;
2035 }
2036 BUG_ON(len);
2037 return csum;
2038}
2039EXPORT_SYMBOL(skb_copy_and_csum_bits);
2040
2041void skb_copy_and_csum_dev(const struct sk_buff *skb, u8 *to)
2042{
2043 __wsum csum;
2044 long csstart;
2045
2046 if (skb->ip_summed == CHECKSUM_PARTIAL)
2047 csstart = skb_checksum_start_offset(skb);
2048 else
2049 csstart = skb_headlen(skb);
2050
2051 BUG_ON(csstart > skb_headlen(skb));
2052
2053 skb_copy_from_linear_data(skb, to, csstart);
2054
2055 csum = 0;
2056 if (csstart != skb->len)
2057 csum = skb_copy_and_csum_bits(skb, csstart, to + csstart,
2058 skb->len - csstart, 0);
2059
2060 if (skb->ip_summed == CHECKSUM_PARTIAL) {
2061 long csstuff = csstart + skb->csum_offset;
2062
2063 *((__sum16 *)(to + csstuff)) = csum_fold(csum);
2064 }
2065}
2066EXPORT_SYMBOL(skb_copy_and_csum_dev);
2067
2068/**
2069 * skb_dequeue - remove from the head of the queue
2070 * @list: list to dequeue from
2071 *
2072 * Remove the head of the list. The list lock is taken so the function
2073 * may be used safely with other locking list functions. The head item is
2074 * returned or %NULL if the list is empty.
2075 */
2076
2077struct sk_buff *skb_dequeue(struct sk_buff_head *list)
2078{
2079 unsigned long flags;
2080 struct sk_buff *result;
2081
2082 spin_lock_irqsave(&list->lock, flags);
2083 result = __skb_dequeue(list);
2084 spin_unlock_irqrestore(&list->lock, flags);
2085 return result;
2086}
2087EXPORT_SYMBOL(skb_dequeue);
2088
2089/**
2090 * skb_dequeue_tail - remove from the tail of the queue
2091 * @list: list to dequeue from
2092 *
2093 * Remove the tail of the list. The list lock is taken so the function
2094 * may be used safely with other locking list functions. The tail item is
2095 * returned or %NULL if the list is empty.
2096 */
2097struct sk_buff *skb_dequeue_tail(struct sk_buff_head *list)
2098{
2099 unsigned long flags;
2100 struct sk_buff *result;
2101
2102 spin_lock_irqsave(&list->lock, flags);
2103 result = __skb_dequeue_tail(list);
2104 spin_unlock_irqrestore(&list->lock, flags);
2105 return result;
2106}
2107EXPORT_SYMBOL(skb_dequeue_tail);
2108
2109/**
2110 * skb_queue_purge - empty a list
2111 * @list: list to empty
2112 *
2113 * Delete all buffers on an &sk_buff list. Each buffer is removed from
2114 * the list and one reference dropped. This function takes the list
2115 * lock and is atomic with respect to other list locking functions.
2116 */
2117void skb_queue_purge(struct sk_buff_head *list)
2118{
2119 struct sk_buff *skb;
2120 while ((skb = skb_dequeue(list)) != NULL)
2121 kfree_skb(skb);
2122}
2123EXPORT_SYMBOL(skb_queue_purge);
2124
2125/**
2126 * skb_queue_head - queue a buffer at the list head
2127 * @list: list to use
2128 * @newsk: buffer to queue
2129 *
2130 * Queue a buffer at the start of the list. This function takes the
2131 * list lock and can be used safely with other locking &sk_buff functions
2132 * safely.
2133 *
2134 * A buffer cannot be placed on two lists at the same time.
2135 */
2136void skb_queue_head(struct sk_buff_head *list, struct sk_buff *newsk)
2137{
2138 unsigned long flags;
2139
2140 spin_lock_irqsave(&list->lock, flags);
2141 __skb_queue_head(list, newsk);
2142 spin_unlock_irqrestore(&list->lock, flags);
2143}
2144EXPORT_SYMBOL(skb_queue_head);
2145
2146/**
2147 * skb_queue_tail - queue a buffer at the list tail
2148 * @list: list to use
2149 * @newsk: buffer to queue
2150 *
2151 * Queue a buffer at the tail of the list. This function takes the
2152 * list lock and can be used safely with other locking &sk_buff functions
2153 * safely.
2154 *
2155 * A buffer cannot be placed on two lists at the same time.
2156 */
2157void skb_queue_tail(struct sk_buff_head *list, struct sk_buff *newsk)
2158{
2159 unsigned long flags;
2160
2161 spin_lock_irqsave(&list->lock, flags);
2162 __skb_queue_tail(list, newsk);
2163 spin_unlock_irqrestore(&list->lock, flags);
2164}
2165EXPORT_SYMBOL(skb_queue_tail);
2166
2167/**
2168 * skb_unlink - remove a buffer from a list
2169 * @skb: buffer to remove
2170 * @list: list to use
2171 *
2172 * Remove a packet from a list. The list locks are taken and this
2173 * function is atomic with respect to other list locked calls
2174 *
2175 * You must know what list the SKB is on.
2176 */
2177void skb_unlink(struct sk_buff *skb, struct sk_buff_head *list)
2178{
2179 unsigned long flags;
2180
2181 spin_lock_irqsave(&list->lock, flags);
2182 __skb_unlink(skb, list);
2183 spin_unlock_irqrestore(&list->lock, flags);
2184}
2185EXPORT_SYMBOL(skb_unlink);
2186
2187/**
2188 * skb_append - append a buffer
2189 * @old: buffer to insert after
2190 * @newsk: buffer to insert
2191 * @list: list to use
2192 *
2193 * Place a packet after a given packet in a list. The list locks are taken
2194 * and this function is atomic with respect to other list locked calls.
2195 * A buffer cannot be placed on two lists at the same time.
2196 */
2197void skb_append(struct sk_buff *old, struct sk_buff *newsk, struct sk_buff_head *list)
2198{
2199 unsigned long flags;
2200
2201 spin_lock_irqsave(&list->lock, flags);
2202 __skb_queue_after(list, old, newsk);
2203 spin_unlock_irqrestore(&list->lock, flags);
2204}
2205EXPORT_SYMBOL(skb_append);
2206
2207/**
2208 * skb_insert - insert a buffer
2209 * @old: buffer to insert before
2210 * @newsk: buffer to insert
2211 * @list: list to use
2212 *
2213 * Place a packet before a given packet in a list. The list locks are
2214 * taken and this function is atomic with respect to other list locked
2215 * calls.
2216 *
2217 * A buffer cannot be placed on two lists at the same time.
2218 */
2219void skb_insert(struct sk_buff *old, struct sk_buff *newsk, struct sk_buff_head *list)
2220{
2221 unsigned long flags;
2222
2223 spin_lock_irqsave(&list->lock, flags);
2224 __skb_insert(newsk, old->prev, old, list);
2225 spin_unlock_irqrestore(&list->lock, flags);
2226}
2227EXPORT_SYMBOL(skb_insert);
2228
2229static inline void skb_split_inside_header(struct sk_buff *skb,
2230 struct sk_buff* skb1,
2231 const u32 len, const int pos)
2232{
2233 int i;
2234
2235 skb_copy_from_linear_data_offset(skb, len, skb_put(skb1, pos - len),
2236 pos - len);
2237 /* And move data appendix as is. */
2238 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
2239 skb_shinfo(skb1)->frags[i] = skb_shinfo(skb)->frags[i];
2240
2241 skb_shinfo(skb1)->nr_frags = skb_shinfo(skb)->nr_frags;
2242 skb_shinfo(skb)->nr_frags = 0;
2243 skb1->data_len = skb->data_len;
2244 skb1->len += skb1->data_len;
2245 skb->data_len = 0;
2246 skb->len = len;
2247 skb_set_tail_pointer(skb, len);
2248}
2249
2250static inline void skb_split_no_header(struct sk_buff *skb,
2251 struct sk_buff* skb1,
2252 const u32 len, int pos)
2253{
2254 int i, k = 0;
2255 const int nfrags = skb_shinfo(skb)->nr_frags;
2256
2257 skb_shinfo(skb)->nr_frags = 0;
2258 skb1->len = skb1->data_len = skb->len - len;
2259 skb->len = len;
2260 skb->data_len = len - pos;
2261
2262 for (i = 0; i < nfrags; i++) {
2263 int size = skb_frag_size(&skb_shinfo(skb)->frags[i]);
2264
2265 if (pos + size > len) {
2266 skb_shinfo(skb1)->frags[k] = skb_shinfo(skb)->frags[i];
2267
2268 if (pos < len) {
2269 /* Split frag.
2270 * We have two variants in this case:
2271 * 1. Move all the frag to the second
2272 * part, if it is possible. F.e.
2273 * this approach is mandatory for TUX,
2274 * where splitting is expensive.
2275 * 2. Split is accurately. We make this.
2276 */
2277 skb_frag_ref(skb, i);
2278 skb_shinfo(skb1)->frags[0].page_offset += len - pos;
2279 skb_frag_size_sub(&skb_shinfo(skb1)->frags[0], len - pos);
2280 skb_frag_size_set(&skb_shinfo(skb)->frags[i], len - pos);
2281 skb_shinfo(skb)->nr_frags++;
2282 }
2283 k++;
2284 } else
2285 skb_shinfo(skb)->nr_frags++;
2286 pos += size;
2287 }
2288 skb_shinfo(skb1)->nr_frags = k;
2289}
2290
2291/**
2292 * skb_split - Split fragmented skb to two parts at length len.
2293 * @skb: the buffer to split
2294 * @skb1: the buffer to receive the second part
2295 * @len: new length for skb
2296 */
2297void skb_split(struct sk_buff *skb, struct sk_buff *skb1, const u32 len)
2298{
2299 int pos = skb_headlen(skb);
2300
2301 if (len < pos) /* Split line is inside header. */
2302 skb_split_inside_header(skb, skb1, len, pos);
2303 else /* Second chunk has no header, nothing to copy. */
2304 skb_split_no_header(skb, skb1, len, pos);
2305}
2306EXPORT_SYMBOL(skb_split);
2307
2308/* Shifting from/to a cloned skb is a no-go.
2309 *
2310 * Caller cannot keep skb_shinfo related pointers past calling here!
2311 */
2312static int skb_prepare_for_shift(struct sk_buff *skb)
2313{
2314 return skb_cloned(skb) && pskb_expand_head(skb, 0, 0, GFP_ATOMIC);
2315}
2316
2317/**
2318 * skb_shift - Shifts paged data partially from skb to another
2319 * @tgt: buffer into which tail data gets added
2320 * @skb: buffer from which the paged data comes from
2321 * @shiftlen: shift up to this many bytes
2322 *
2323 * Attempts to shift up to shiftlen worth of bytes, which may be less than
2324 * the length of the skb, from skb to tgt. Returns number bytes shifted.
2325 * It's up to caller to free skb if everything was shifted.
2326 *
2327 * If @tgt runs out of frags, the whole operation is aborted.
2328 *
2329 * Skb cannot include anything else but paged data while tgt is allowed
2330 * to have non-paged data as well.
2331 *
2332 * TODO: full sized shift could be optimized but that would need
2333 * specialized skb free'er to handle frags without up-to-date nr_frags.
2334 */
2335int skb_shift(struct sk_buff *tgt, struct sk_buff *skb, int shiftlen)
2336{
2337 int from, to, merge, todo;
2338 struct skb_frag_struct *fragfrom, *fragto;
2339
2340 BUG_ON(shiftlen > skb->len);
2341 BUG_ON(skb_headlen(skb)); /* Would corrupt stream */
2342
2343 todo = shiftlen;
2344 from = 0;
2345 to = skb_shinfo(tgt)->nr_frags;
2346 fragfrom = &skb_shinfo(skb)->frags[from];
2347
2348 /* Actual merge is delayed until the point when we know we can
2349 * commit all, so that we don't have to undo partial changes
2350 */
2351 if (!to ||
2352 !skb_can_coalesce(tgt, to, skb_frag_page(fragfrom),
2353 fragfrom->page_offset)) {
2354 merge = -1;
2355 } else {
2356 merge = to - 1;
2357
2358 todo -= skb_frag_size(fragfrom);
2359 if (todo < 0) {
2360 if (skb_prepare_for_shift(skb) ||
2361 skb_prepare_for_shift(tgt))
2362 return 0;
2363
2364 /* All previous frag pointers might be stale! */
2365 fragfrom = &skb_shinfo(skb)->frags[from];
2366 fragto = &skb_shinfo(tgt)->frags[merge];
2367
2368 skb_frag_size_add(fragto, shiftlen);
2369 skb_frag_size_sub(fragfrom, shiftlen);
2370 fragfrom->page_offset += shiftlen;
2371
2372 goto onlymerged;
2373 }
2374
2375 from++;
2376 }
2377
2378 /* Skip full, not-fitting skb to avoid expensive operations */
2379 if ((shiftlen == skb->len) &&
2380 (skb_shinfo(skb)->nr_frags - from) > (MAX_SKB_FRAGS - to))
2381 return 0;
2382
2383 if (skb_prepare_for_shift(skb) || skb_prepare_for_shift(tgt))
2384 return 0;
2385
2386 while ((todo > 0) && (from < skb_shinfo(skb)->nr_frags)) {
2387 if (to == MAX_SKB_FRAGS)
2388 return 0;
2389
2390 fragfrom = &skb_shinfo(skb)->frags[from];
2391 fragto = &skb_shinfo(tgt)->frags[to];
2392
2393 if (todo >= skb_frag_size(fragfrom)) {
2394 *fragto = *fragfrom;
2395 todo -= skb_frag_size(fragfrom);
2396 from++;
2397 to++;
2398
2399 } else {
2400 __skb_frag_ref(fragfrom);
2401 fragto->page = fragfrom->page;
2402 fragto->page_offset = fragfrom->page_offset;
2403 skb_frag_size_set(fragto, todo);
2404
2405 fragfrom->page_offset += todo;
2406 skb_frag_size_sub(fragfrom, todo);
2407 todo = 0;
2408
2409 to++;
2410 break;
2411 }
2412 }
2413
2414 /* Ready to "commit" this state change to tgt */
2415 skb_shinfo(tgt)->nr_frags = to;
2416
2417 if (merge >= 0) {
2418 fragfrom = &skb_shinfo(skb)->frags[0];
2419 fragto = &skb_shinfo(tgt)->frags[merge];
2420
2421 skb_frag_size_add(fragto, skb_frag_size(fragfrom));
2422 __skb_frag_unref(fragfrom);
2423 }
2424
2425 /* Reposition in the original skb */
2426 to = 0;
2427 while (from < skb_shinfo(skb)->nr_frags)
2428 skb_shinfo(skb)->frags[to++] = skb_shinfo(skb)->frags[from++];
2429 skb_shinfo(skb)->nr_frags = to;
2430
2431 BUG_ON(todo > 0 && !skb_shinfo(skb)->nr_frags);
2432
2433onlymerged:
2434 /* Most likely the tgt won't ever need its checksum anymore, skb on
2435 * the other hand might need it if it needs to be resent
2436 */
2437 tgt->ip_summed = CHECKSUM_PARTIAL;
2438 skb->ip_summed = CHECKSUM_PARTIAL;
2439
2440 /* Yak, is it really working this way? Some helper please? */
2441 skb->len -= shiftlen;
2442 skb->data_len -= shiftlen;
2443 skb->truesize -= shiftlen;
2444 tgt->len += shiftlen;
2445 tgt->data_len += shiftlen;
2446 tgt->truesize += shiftlen;
2447
2448 return shiftlen;
2449}
2450
2451/**
2452 * skb_prepare_seq_read - Prepare a sequential read of skb data
2453 * @skb: the buffer to read
2454 * @from: lower offset of data to be read
2455 * @to: upper offset of data to be read
2456 * @st: state variable
2457 *
2458 * Initializes the specified state variable. Must be called before
2459 * invoking skb_seq_read() for the first time.
2460 */
2461void skb_prepare_seq_read(struct sk_buff *skb, unsigned int from,
2462 unsigned int to, struct skb_seq_state *st)
2463{
2464 st->lower_offset = from;
2465 st->upper_offset = to;
2466 st->root_skb = st->cur_skb = skb;
2467 st->frag_idx = st->stepped_offset = 0;
2468 st->frag_data = NULL;
2469}
2470EXPORT_SYMBOL(skb_prepare_seq_read);
2471
2472/**
2473 * skb_seq_read - Sequentially read skb data
2474 * @consumed: number of bytes consumed by the caller so far
2475 * @data: destination pointer for data to be returned
2476 * @st: state variable
2477 *
2478 * Reads a block of skb data at &consumed relative to the
2479 * lower offset specified to skb_prepare_seq_read(). Assigns
2480 * the head of the data block to &data and returns the length
2481 * of the block or 0 if the end of the skb data or the upper
2482 * offset has been reached.
2483 *
2484 * The caller is not required to consume all of the data
2485 * returned, i.e. &consumed is typically set to the number
2486 * of bytes already consumed and the next call to
2487 * skb_seq_read() will return the remaining part of the block.
2488 *
2489 * Note 1: The size of each block of data returned can be arbitrary,
2490 * this limitation is the cost for zerocopy seqeuental
2491 * reads of potentially non linear data.
2492 *
2493 * Note 2: Fragment lists within fragments are not implemented
2494 * at the moment, state->root_skb could be replaced with
2495 * a stack for this purpose.
2496 */
2497unsigned int skb_seq_read(unsigned int consumed, const u8 **data,
2498 struct skb_seq_state *st)
2499{
2500 unsigned int block_limit, abs_offset = consumed + st->lower_offset;
2501 skb_frag_t *frag;
2502
2503 if (unlikely(abs_offset >= st->upper_offset))
2504 return 0;
2505
2506next_skb:
2507 block_limit = skb_headlen(st->cur_skb) + st->stepped_offset;
2508
2509 if (abs_offset < block_limit && !st->frag_data) {
2510 *data = st->cur_skb->data + (abs_offset - st->stepped_offset);
2511 return block_limit - abs_offset;
2512 }
2513
2514 if (st->frag_idx == 0 && !st->frag_data)
2515 st->stepped_offset += skb_headlen(st->cur_skb);
2516
2517 while (st->frag_idx < skb_shinfo(st->cur_skb)->nr_frags) {
2518 frag = &skb_shinfo(st->cur_skb)->frags[st->frag_idx];
2519 block_limit = skb_frag_size(frag) + st->stepped_offset;
2520
2521 if (abs_offset < block_limit) {
2522 if (!st->frag_data)
2523 st->frag_data = kmap_atomic(skb_frag_page(frag));
2524
2525 *data = (u8 *) st->frag_data + frag->page_offset +
2526 (abs_offset - st->stepped_offset);
2527
2528 return block_limit - abs_offset;
2529 }
2530
2531 if (st->frag_data) {
2532 kunmap_atomic(st->frag_data);
2533 st->frag_data = NULL;
2534 }
2535
2536 st->frag_idx++;
2537 st->stepped_offset += skb_frag_size(frag);
2538 }
2539
2540 if (st->frag_data) {
2541 kunmap_atomic(st->frag_data);
2542 st->frag_data = NULL;
2543 }
2544
2545 if (st->root_skb == st->cur_skb && skb_has_frag_list(st->root_skb)) {
2546 st->cur_skb = skb_shinfo(st->root_skb)->frag_list;
2547 st->frag_idx = 0;
2548 goto next_skb;
2549 } else if (st->cur_skb->next) {
2550 st->cur_skb = st->cur_skb->next;
2551 st->frag_idx = 0;
2552 goto next_skb;
2553 }
2554
2555 return 0;
2556}
2557EXPORT_SYMBOL(skb_seq_read);
2558
2559/**
2560 * skb_abort_seq_read - Abort a sequential read of skb data
2561 * @st: state variable
2562 *
2563 * Must be called if skb_seq_read() was not called until it
2564 * returned 0.
2565 */
2566void skb_abort_seq_read(struct skb_seq_state *st)
2567{
2568 if (st->frag_data)
2569 kunmap_atomic(st->frag_data);
2570}
2571EXPORT_SYMBOL(skb_abort_seq_read);
2572
2573#define TS_SKB_CB(state) ((struct skb_seq_state *) &((state)->cb))
2574
2575static unsigned int skb_ts_get_next_block(unsigned int offset, const u8 **text,
2576 struct ts_config *conf,
2577 struct ts_state *state)
2578{
2579 return skb_seq_read(offset, text, TS_SKB_CB(state));
2580}
2581
2582static void skb_ts_finish(struct ts_config *conf, struct ts_state *state)
2583{
2584 skb_abort_seq_read(TS_SKB_CB(state));
2585}
2586
2587/**
2588 * skb_find_text - Find a text pattern in skb data
2589 * @skb: the buffer to look in
2590 * @from: search offset
2591 * @to: search limit
2592 * @config: textsearch configuration
2593 * @state: uninitialized textsearch state variable
2594 *
2595 * Finds a pattern in the skb data according to the specified
2596 * textsearch configuration. Use textsearch_next() to retrieve
2597 * subsequent occurrences of the pattern. Returns the offset
2598 * to the first occurrence or UINT_MAX if no match was found.
2599 */
2600unsigned int skb_find_text(struct sk_buff *skb, unsigned int from,
2601 unsigned int to, struct ts_config *config,
2602 struct ts_state *state)
2603{
2604 unsigned int ret;
2605
2606 config->get_next_block = skb_ts_get_next_block;
2607 config->finish = skb_ts_finish;
2608
2609 skb_prepare_seq_read(skb, from, to, TS_SKB_CB(state));
2610
2611 ret = textsearch_find(config, state);
2612 return (ret <= to - from ? ret : UINT_MAX);
2613}
2614EXPORT_SYMBOL(skb_find_text);
2615
2616/**
2617 * skb_append_datato_frags: - append the user data to a skb
2618 * @sk: sock structure
2619 * @skb: skb structure to be appened with user data.
2620 * @getfrag: call back function to be used for getting the user data
2621 * @from: pointer to user message iov
2622 * @length: length of the iov message
2623 *
2624 * Description: This procedure append the user data in the fragment part
2625 * of the skb if any page alloc fails user this procedure returns -ENOMEM
2626 */
2627int skb_append_datato_frags(struct sock *sk, struct sk_buff *skb,
2628 int (*getfrag)(void *from, char *to, int offset,
2629 int len, int odd, struct sk_buff *skb),
2630 void *from, int length)
2631{
2632 int frg_cnt = 0;
2633 skb_frag_t *frag = NULL;
2634 struct page *page = NULL;
2635 int copy, left;
2636 int offset = 0;
2637 int ret;
2638
2639 do {
2640 /* Return error if we don't have space for new frag */
2641 frg_cnt = skb_shinfo(skb)->nr_frags;
2642 if (frg_cnt >= MAX_SKB_FRAGS)
2643 return -EFAULT;
2644
2645 /* allocate a new page for next frag */
2646 page = alloc_pages(sk->sk_allocation, 0);
2647
2648 /* If alloc_page fails just return failure and caller will
2649 * free previous allocated pages by doing kfree_skb()
2650 */
2651 if (page == NULL)
2652 return -ENOMEM;
2653
2654 /* initialize the next frag */
2655 skb_fill_page_desc(skb, frg_cnt, page, 0, 0);
2656 skb->truesize += PAGE_SIZE;
2657 atomic_add(PAGE_SIZE, &sk->sk_wmem_alloc);
2658
2659 /* get the new initialized frag */
2660 frg_cnt = skb_shinfo(skb)->nr_frags;
2661 frag = &skb_shinfo(skb)->frags[frg_cnt - 1];
2662
2663 /* copy the user data to page */
2664 left = PAGE_SIZE - frag->page_offset;
2665 copy = (length > left)? left : length;
2666
2667 ret = getfrag(from, skb_frag_address(frag) + skb_frag_size(frag),
2668 offset, copy, 0, skb);
2669 if (ret < 0)
2670 return -EFAULT;
2671
2672 /* copy was successful so update the size parameters */
2673 skb_frag_size_add(frag, copy);
2674 skb->len += copy;
2675 skb->data_len += copy;
2676 offset += copy;
2677 length -= copy;
2678
2679 } while (length > 0);
2680
2681 return 0;
2682}
2683EXPORT_SYMBOL(skb_append_datato_frags);
2684
2685/**
2686 * skb_pull_rcsum - pull skb and update receive checksum
2687 * @skb: buffer to update
2688 * @len: length of data pulled
2689 *
2690 * This function performs an skb_pull on the packet and updates
2691 * the CHECKSUM_COMPLETE checksum. It should be used on
2692 * receive path processing instead of skb_pull unless you know
2693 * that the checksum difference is zero (e.g., a valid IP header)
2694 * or you are setting ip_summed to CHECKSUM_NONE.
2695 */
2696unsigned char *skb_pull_rcsum(struct sk_buff *skb, unsigned int len)
2697{
2698 BUG_ON(len > skb->len);
2699 skb->len -= len;
2700 BUG_ON(skb->len < skb->data_len);
2701 skb_postpull_rcsum(skb, skb->data, len);
2702 return skb->data += len;
2703}
2704EXPORT_SYMBOL_GPL(skb_pull_rcsum);
2705
2706/**
2707 * skb_segment - Perform protocol segmentation on skb.
2708 * @skb: buffer to segment
2709 * @features: features for the output path (see dev->features)
2710 *
2711 * This function performs segmentation on the given skb. It returns
2712 * a pointer to the first in a list of new skbs for the segments.
2713 * In case of error it returns ERR_PTR(err).
2714 */
2715struct sk_buff *skb_segment(struct sk_buff *skb, netdev_features_t features)
2716{
2717 struct sk_buff *segs = NULL;
2718 struct sk_buff *tail = NULL;
2719 struct sk_buff *fskb = skb_shinfo(skb)->frag_list;
2720 unsigned int mss = skb_shinfo(skb)->gso_size;
2721 unsigned int doffset = skb->data - skb_mac_header(skb);
2722 unsigned int offset = doffset;
2723 unsigned int headroom;
2724 unsigned int len;
2725 int sg = !!(features & NETIF_F_SG);
2726 int nfrags = skb_shinfo(skb)->nr_frags;
2727 int err = -ENOMEM;
2728 int i = 0;
2729 int pos;
2730
2731 __skb_push(skb, doffset);
2732 headroom = skb_headroom(skb);
2733 pos = skb_headlen(skb);
2734
2735 do {
2736 struct sk_buff *nskb;
2737 skb_frag_t *frag;
2738 int hsize;
2739 int size;
2740
2741 len = skb->len - offset;
2742 if (len > mss)
2743 len = mss;
2744
2745 hsize = skb_headlen(skb) - offset;
2746 if (hsize < 0)
2747 hsize = 0;
2748 if (hsize > len || !sg)
2749 hsize = len;
2750
2751 if (!hsize && i >= nfrags) {
2752 BUG_ON(fskb->len != len);
2753
2754 pos += len;
2755 nskb = skb_clone(fskb, GFP_ATOMIC);
2756 fskb = fskb->next;
2757
2758 if (unlikely(!nskb))
2759 goto err;
2760
2761 hsize = skb_end_offset(nskb);
2762 if (skb_cow_head(nskb, doffset + headroom)) {
2763 kfree_skb(nskb);
2764 goto err;
2765 }
2766
2767 nskb->truesize += skb_end_offset(nskb) - hsize;
2768 skb_release_head_state(nskb);
2769 __skb_push(nskb, doffset);
2770 } else {
2771 nskb = alloc_skb(hsize + doffset + headroom,
2772 GFP_ATOMIC);
2773
2774 if (unlikely(!nskb))
2775 goto err;
2776
2777 skb_reserve(nskb, headroom);
2778 __skb_put(nskb, doffset);
2779 }
2780
2781 if (segs)
2782 tail->next = nskb;
2783 else
2784 segs = nskb;
2785 tail = nskb;
2786
2787 __copy_skb_header(nskb, skb);
2788 nskb->mac_len = skb->mac_len;
2789
2790 /* nskb and skb might have different headroom */
2791 if (nskb->ip_summed == CHECKSUM_PARTIAL)
2792 nskb->csum_start += skb_headroom(nskb) - headroom;
2793
2794 skb_reset_mac_header(nskb);
2795 skb_set_network_header(nskb, skb->mac_len);
2796 nskb->transport_header = (nskb->network_header +
2797 skb_network_header_len(skb));
2798 skb_copy_from_linear_data(skb, nskb->data, doffset);
2799
2800 if (fskb != skb_shinfo(skb)->frag_list)
2801 continue;
2802
2803 if (!sg) {
2804 nskb->ip_summed = CHECKSUM_NONE;
2805 nskb->csum = skb_copy_and_csum_bits(skb, offset,
2806 skb_put(nskb, len),
2807 len, 0);
2808 continue;
2809 }
2810
2811 frag = skb_shinfo(nskb)->frags;
2812
2813 skb_copy_from_linear_data_offset(skb, offset,
2814 skb_put(nskb, hsize), hsize);
2815
2816 while (pos < offset + len && i < nfrags) {
2817 *frag = skb_shinfo(skb)->frags[i];
2818 __skb_frag_ref(frag);
2819 size = skb_frag_size(frag);
2820
2821 if (pos < offset) {
2822 frag->page_offset += offset - pos;
2823 skb_frag_size_sub(frag, offset - pos);
2824 }
2825
2826 skb_shinfo(nskb)->nr_frags++;
2827
2828 if (pos + size <= offset + len) {
2829 i++;
2830 pos += size;
2831 } else {
2832 skb_frag_size_sub(frag, pos + size - (offset + len));
2833 goto skip_fraglist;
2834 }
2835
2836 frag++;
2837 }
2838
2839 if (pos < offset + len) {
2840 struct sk_buff *fskb2 = fskb;
2841
2842 BUG_ON(pos + fskb->len != offset + len);
2843
2844 pos += fskb->len;
2845 fskb = fskb->next;
2846
2847 if (fskb2->next) {
2848 fskb2 = skb_clone(fskb2, GFP_ATOMIC);
2849 if (!fskb2)
2850 goto err;
2851 } else
2852 skb_get(fskb2);
2853
2854 SKB_FRAG_ASSERT(nskb);
2855 skb_shinfo(nskb)->frag_list = fskb2;
2856 }
2857
2858skip_fraglist:
2859 nskb->data_len = len - hsize;
2860 nskb->len += nskb->data_len;
2861 nskb->truesize += nskb->data_len;
2862 } while ((offset += len) < skb->len);
2863
2864 return segs;
2865
2866err:
2867 while ((skb = segs)) {
2868 segs = skb->next;
2869 kfree_skb(skb);
2870 }
2871 return ERR_PTR(err);
2872}
2873EXPORT_SYMBOL_GPL(skb_segment);
2874
2875int skb_gro_receive(struct sk_buff **head, struct sk_buff *skb)
2876{
2877 struct sk_buff *p = *head;
2878 struct sk_buff *nskb;
2879 struct skb_shared_info *skbinfo = skb_shinfo(skb);
2880 struct skb_shared_info *pinfo = skb_shinfo(p);
2881 unsigned int headroom;
2882 unsigned int len = skb_gro_len(skb);
2883 unsigned int offset = skb_gro_offset(skb);
2884 unsigned int headlen = skb_headlen(skb);
2885 unsigned int delta_truesize;
2886
2887 if (p->len + len >= 65536)
2888 return -E2BIG;
2889
2890 if (pinfo->frag_list)
2891 goto merge;
2892 else if (headlen <= offset) {
2893 skb_frag_t *frag;
2894 skb_frag_t *frag2;
2895 int i = skbinfo->nr_frags;
2896 int nr_frags = pinfo->nr_frags + i;
2897
2898 offset -= headlen;
2899
2900 if (nr_frags > MAX_SKB_FRAGS)
2901 return -E2BIG;
2902
2903 pinfo->nr_frags = nr_frags;
2904 skbinfo->nr_frags = 0;
2905
2906 frag = pinfo->frags + nr_frags;
2907 frag2 = skbinfo->frags + i;
2908 do {
2909 *--frag = *--frag2;
2910 } while (--i);
2911
2912 frag->page_offset += offset;
2913 skb_frag_size_sub(frag, offset);
2914
2915 /* all fragments truesize : remove (head size + sk_buff) */
2916 delta_truesize = skb->truesize -
2917 SKB_TRUESIZE(skb_end_offset(skb));
2918
2919 skb->truesize -= skb->data_len;
2920 skb->len -= skb->data_len;
2921 skb->data_len = 0;
2922
2923 NAPI_GRO_CB(skb)->free = NAPI_GRO_FREE;
2924 goto done;
2925 } else if (skb->head_frag) {
2926 int nr_frags = pinfo->nr_frags;
2927 skb_frag_t *frag = pinfo->frags + nr_frags;
2928 struct page *page = virt_to_head_page(skb->head);
2929 unsigned int first_size = headlen - offset;
2930 unsigned int first_offset;
2931
2932 if (nr_frags + 1 + skbinfo->nr_frags > MAX_SKB_FRAGS)
2933 return -E2BIG;
2934
2935 first_offset = skb->data -
2936 (unsigned char *)page_address(page) +
2937 offset;
2938
2939 pinfo->nr_frags = nr_frags + 1 + skbinfo->nr_frags;
2940
2941 frag->page.p = page;
2942 frag->page_offset = first_offset;
2943 skb_frag_size_set(frag, first_size);
2944
2945 memcpy(frag + 1, skbinfo->frags, sizeof(*frag) * skbinfo->nr_frags);
2946 /* We dont need to clear skbinfo->nr_frags here */
2947
2948 delta_truesize = skb->truesize - SKB_DATA_ALIGN(sizeof(struct sk_buff));
2949 NAPI_GRO_CB(skb)->free = NAPI_GRO_FREE_STOLEN_HEAD;
2950 goto done;
2951 } else if (skb_gro_len(p) != pinfo->gso_size)
2952 return -E2BIG;
2953
2954 headroom = skb_headroom(p);
2955 nskb = alloc_skb(headroom + skb_gro_offset(p), GFP_ATOMIC);
2956 if (unlikely(!nskb))
2957 return -ENOMEM;
2958
2959 __copy_skb_header(nskb, p);
2960 nskb->mac_len = p->mac_len;
2961
2962 skb_reserve(nskb, headroom);
2963 __skb_put(nskb, skb_gro_offset(p));
2964
2965 skb_set_mac_header(nskb, skb_mac_header(p) - p->data);
2966 skb_set_network_header(nskb, skb_network_offset(p));
2967 skb_set_transport_header(nskb, skb_transport_offset(p));
2968
2969 __skb_pull(p, skb_gro_offset(p));
2970 memcpy(skb_mac_header(nskb), skb_mac_header(p),
2971 p->data - skb_mac_header(p));
2972
2973 *NAPI_GRO_CB(nskb) = *NAPI_GRO_CB(p);
2974 skb_shinfo(nskb)->frag_list = p;
2975 skb_shinfo(nskb)->gso_size = pinfo->gso_size;
2976 pinfo->gso_size = 0;
2977 skb_header_release(p);
2978 nskb->prev = p;
2979
2980 nskb->data_len += p->len;
2981 nskb->truesize += p->truesize;
2982 nskb->len += p->len;
2983
2984 *head = nskb;
2985 nskb->next = p->next;
2986 p->next = NULL;
2987
2988 p = nskb;
2989
2990merge:
2991 delta_truesize = skb->truesize;
2992 if (offset > headlen) {
2993 unsigned int eat = offset - headlen;
2994
2995 skbinfo->frags[0].page_offset += eat;
2996 skb_frag_size_sub(&skbinfo->frags[0], eat);
2997 skb->data_len -= eat;
2998 skb->len -= eat;
2999 offset = headlen;
3000 }
3001
3002 __skb_pull(skb, offset);
3003
3004 p->prev->next = skb;
3005 p->prev = skb;
3006 skb_header_release(skb);
3007
3008done:
3009 NAPI_GRO_CB(p)->count++;
3010 p->data_len += len;
3011 p->truesize += delta_truesize;
3012 p->len += len;
3013
3014 NAPI_GRO_CB(skb)->same_flow = 1;
3015 return 0;
3016}
3017EXPORT_SYMBOL_GPL(skb_gro_receive);
3018
3019void __init skb_init(void)
3020{
3021 skbuff_head_cache = kmem_cache_create("skbuff_head_cache",
3022 sizeof(struct sk_buff),
3023 0,
3024 SLAB_HWCACHE_ALIGN|SLAB_PANIC,
3025 NULL);
3026 skbuff_fclone_cache = kmem_cache_create("skbuff_fclone_cache",
3027 (2*sizeof(struct sk_buff)) +
3028 sizeof(atomic_t),
3029 0,
3030 SLAB_HWCACHE_ALIGN|SLAB_PANIC,
3031 NULL);
3032}
3033
3034/**
3035 * skb_to_sgvec - Fill a scatter-gather list from a socket buffer
3036 * @skb: Socket buffer containing the buffers to be mapped
3037 * @sg: The scatter-gather list to map into
3038 * @offset: The offset into the buffer's contents to start mapping
3039 * @len: Length of buffer space to be mapped
3040 *
3041 * Fill the specified scatter-gather list with mappings/pointers into a
3042 * region of the buffer space attached to a socket buffer.
3043 */
3044static int
3045__skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int len)
3046{
3047 int start = skb_headlen(skb);
3048 int i, copy = start - offset;
3049 struct sk_buff *frag_iter;
3050 int elt = 0;
3051
3052 if (copy > 0) {
3053 if (copy > len)
3054 copy = len;
3055 sg_set_buf(sg, skb->data + offset, copy);
3056 elt++;
3057 if ((len -= copy) == 0)
3058 return elt;
3059 offset += copy;
3060 }
3061
3062 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
3063 int end;
3064
3065 WARN_ON(start > offset + len);
3066
3067 end = start + skb_frag_size(&skb_shinfo(skb)->frags[i]);
3068 if ((copy = end - offset) > 0) {
3069 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
3070
3071 if (copy > len)
3072 copy = len;
3073 sg_set_page(&sg[elt], skb_frag_page(frag), copy,
3074 frag->page_offset+offset-start);
3075 elt++;
3076 if (!(len -= copy))
3077 return elt;
3078 offset += copy;
3079 }
3080 start = end;
3081 }
3082
3083 skb_walk_frags(skb, frag_iter) {
3084 int end;
3085
3086 WARN_ON(start > offset + len);
3087
3088 end = start + frag_iter->len;
3089 if ((copy = end - offset) > 0) {
3090 if (copy > len)
3091 copy = len;
3092 elt += __skb_to_sgvec(frag_iter, sg+elt, offset - start,
3093 copy);
3094 if ((len -= copy) == 0)
3095 return elt;
3096 offset += copy;
3097 }
3098 start = end;
3099 }
3100 BUG_ON(len);
3101 return elt;
3102}
3103
3104int skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int len)
3105{
3106 int nsg = __skb_to_sgvec(skb, sg, offset, len);
3107
3108 sg_mark_end(&sg[nsg - 1]);
3109
3110 return nsg;
3111}
3112EXPORT_SYMBOL_GPL(skb_to_sgvec);
3113
3114/**
3115 * skb_cow_data - Check that a socket buffer's data buffers are writable
3116 * @skb: The socket buffer to check.
3117 * @tailbits: Amount of trailing space to be added
3118 * @trailer: Returned pointer to the skb where the @tailbits space begins
3119 *
3120 * Make sure that the data buffers attached to a socket buffer are
3121 * writable. If they are not, private copies are made of the data buffers
3122 * and the socket buffer is set to use these instead.
3123 *
3124 * If @tailbits is given, make sure that there is space to write @tailbits
3125 * bytes of data beyond current end of socket buffer. @trailer will be
3126 * set to point to the skb in which this space begins.
3127 *
3128 * The number of scatterlist elements required to completely map the
3129 * COW'd and extended socket buffer will be returned.
3130 */
3131int skb_cow_data(struct sk_buff *skb, int tailbits, struct sk_buff **trailer)
3132{
3133 int copyflag;
3134 int elt;
3135 struct sk_buff *skb1, **skb_p;
3136
3137 /* If skb is cloned or its head is paged, reallocate
3138 * head pulling out all the pages (pages are considered not writable
3139 * at the moment even if they are anonymous).
3140 */
3141 if ((skb_cloned(skb) || skb_shinfo(skb)->nr_frags) &&
3142 __pskb_pull_tail(skb, skb_pagelen(skb)-skb_headlen(skb)) == NULL)
3143 return -ENOMEM;
3144
3145 /* Easy case. Most of packets will go this way. */
3146 if (!skb_has_frag_list(skb)) {
3147 /* A little of trouble, not enough of space for trailer.
3148 * This should not happen, when stack is tuned to generate
3149 * good frames. OK, on miss we reallocate and reserve even more
3150 * space, 128 bytes is fair. */
3151
3152 if (skb_tailroom(skb) < tailbits &&
3153 pskb_expand_head(skb, 0, tailbits-skb_tailroom(skb)+128, GFP_ATOMIC))
3154 return -ENOMEM;
3155
3156 /* Voila! */
3157 *trailer = skb;
3158 return 1;
3159 }
3160
3161 /* Misery. We are in troubles, going to mincer fragments... */
3162
3163 elt = 1;
3164 skb_p = &skb_shinfo(skb)->frag_list;
3165 copyflag = 0;
3166
3167 while ((skb1 = *skb_p) != NULL) {
3168 int ntail = 0;
3169
3170 /* The fragment is partially pulled by someone,
3171 * this can happen on input. Copy it and everything
3172 * after it. */
3173
3174 if (skb_shared(skb1))
3175 copyflag = 1;
3176
3177 /* If the skb is the last, worry about trailer. */
3178
3179 if (skb1->next == NULL && tailbits) {
3180 if (skb_shinfo(skb1)->nr_frags ||
3181 skb_has_frag_list(skb1) ||
3182 skb_tailroom(skb1) < tailbits)
3183 ntail = tailbits + 128;
3184 }
3185
3186 if (copyflag ||
3187 skb_cloned(skb1) ||
3188 ntail ||
3189 skb_shinfo(skb1)->nr_frags ||
3190 skb_has_frag_list(skb1)) {
3191 struct sk_buff *skb2;
3192
3193 /* Fuck, we are miserable poor guys... */
3194 if (ntail == 0)
3195 skb2 = skb_copy(skb1, GFP_ATOMIC);
3196 else
3197 skb2 = skb_copy_expand(skb1,
3198 skb_headroom(skb1),
3199 ntail,
3200 GFP_ATOMIC);
3201 if (unlikely(skb2 == NULL))
3202 return -ENOMEM;
3203
3204 if (skb1->sk)
3205 skb_set_owner_w(skb2, skb1->sk);
3206
3207 /* Looking around. Are we still alive?
3208 * OK, link new skb, drop old one */
3209
3210 skb2->next = skb1->next;
3211 *skb_p = skb2;
3212 kfree_skb(skb1);
3213 skb1 = skb2;
3214 }
3215 elt++;
3216 *trailer = skb1;
3217 skb_p = &skb1->next;
3218 }
3219
3220 return elt;
3221}
3222EXPORT_SYMBOL_GPL(skb_cow_data);
3223
3224static void sock_rmem_free(struct sk_buff *skb)
3225{
3226 struct sock *sk = skb->sk;
3227
3228 atomic_sub(skb->truesize, &sk->sk_rmem_alloc);
3229}
3230
3231/*
3232 * Note: We dont mem charge error packets (no sk_forward_alloc changes)
3233 */
3234int sock_queue_err_skb(struct sock *sk, struct sk_buff *skb)
3235{
3236 int len = skb->len;
3237
3238 if (atomic_read(&sk->sk_rmem_alloc) + skb->truesize >=
3239 (unsigned int)sk->sk_rcvbuf)
3240 return -ENOMEM;
3241
3242 skb_orphan(skb);
3243 skb->sk = sk;
3244 skb->destructor = sock_rmem_free;
3245 atomic_add(skb->truesize, &sk->sk_rmem_alloc);
3246
3247 /* before exiting rcu section, make sure dst is refcounted */
3248 skb_dst_force(skb);
3249
3250 skb_queue_tail(&sk->sk_error_queue, skb);
3251 if (!sock_flag(sk, SOCK_DEAD))
3252 sk->sk_data_ready(sk, len);
3253 return 0;
3254}
3255EXPORT_SYMBOL(sock_queue_err_skb);
3256
3257void skb_tstamp_tx(struct sk_buff *orig_skb,
3258 struct skb_shared_hwtstamps *hwtstamps)
3259{
3260 struct sock *sk = orig_skb->sk;
3261 struct sock_exterr_skb *serr;
3262 struct sk_buff *skb;
3263 int err;
3264
3265 if (!sk)
3266 return;
3267
3268 skb = skb_clone(orig_skb, GFP_ATOMIC);
3269 if (!skb)
3270 return;
3271
3272 if (hwtstamps) {
3273 *skb_hwtstamps(skb) =
3274 *hwtstamps;
3275 } else {
3276 /*
3277 * no hardware time stamps available,
3278 * so keep the shared tx_flags and only
3279 * store software time stamp
3280 */
3281 skb->tstamp = ktime_get_real();
3282 }
3283
3284 serr = SKB_EXT_ERR(skb);
3285 memset(serr, 0, sizeof(*serr));
3286 serr->ee.ee_errno = ENOMSG;
3287 serr->ee.ee_origin = SO_EE_ORIGIN_TIMESTAMPING;
3288
3289 err = sock_queue_err_skb(sk, skb);
3290
3291 if (err)
3292 kfree_skb(skb);
3293}
3294EXPORT_SYMBOL_GPL(skb_tstamp_tx);
3295
3296void skb_complete_wifi_ack(struct sk_buff *skb, bool acked)
3297{
3298 struct sock *sk = skb->sk;
3299 struct sock_exterr_skb *serr;
3300 int err;
3301
3302 skb->wifi_acked_valid = 1;
3303 skb->wifi_acked = acked;
3304
3305 serr = SKB_EXT_ERR(skb);
3306 memset(serr, 0, sizeof(*serr));
3307 serr->ee.ee_errno = ENOMSG;
3308 serr->ee.ee_origin = SO_EE_ORIGIN_TXSTATUS;
3309
3310 err = sock_queue_err_skb(sk, skb);
3311 if (err)
3312 kfree_skb(skb);
3313}
3314EXPORT_SYMBOL_GPL(skb_complete_wifi_ack);
3315
3316
3317/**
3318 * skb_partial_csum_set - set up and verify partial csum values for packet
3319 * @skb: the skb to set
3320 * @start: the number of bytes after skb->data to start checksumming.
3321 * @off: the offset from start to place the checksum.
3322 *
3323 * For untrusted partially-checksummed packets, we need to make sure the values
3324 * for skb->csum_start and skb->csum_offset are valid so we don't oops.
3325 *
3326 * This function checks and sets those values and skb->ip_summed: if this
3327 * returns false you should drop the packet.
3328 */
3329bool skb_partial_csum_set(struct sk_buff *skb, u16 start, u16 off)
3330{
3331 if (unlikely(start > skb_headlen(skb)) ||
3332 unlikely((int)start + off > skb_headlen(skb) - 2)) {
3333 net_warn_ratelimited("bad partial csum: csum=%u/%u len=%u\n",
3334 start, off, skb_headlen(skb));
3335 return false;
3336 }
3337 skb->ip_summed = CHECKSUM_PARTIAL;
3338 skb->csum_start = skb_headroom(skb) + start;
3339 skb->csum_offset = off;
3340 return true;
3341}
3342EXPORT_SYMBOL_GPL(skb_partial_csum_set);
3343
3344void __skb_warn_lro_forwarding(const struct sk_buff *skb)
3345{
3346 net_warn_ratelimited("%s: received packets cannot be forwarded while LRO is enabled\n",
3347 skb->dev->name);
3348}
3349EXPORT_SYMBOL(__skb_warn_lro_forwarding);
3350
3351void kfree_skb_partial(struct sk_buff *skb, bool head_stolen)
3352{
3353 if (head_stolen)
3354 kmem_cache_free(skbuff_head_cache, skb);
3355 else
3356 __kfree_skb(skb);
3357}
3358EXPORT_SYMBOL(kfree_skb_partial);
3359
3360/**
3361 * skb_try_coalesce - try to merge skb to prior one
3362 * @to: prior buffer
3363 * @from: buffer to add
3364 * @fragstolen: pointer to boolean
3365 * @delta_truesize: how much more was allocated than was requested
3366 */
3367bool skb_try_coalesce(struct sk_buff *to, struct sk_buff *from,
3368 bool *fragstolen, int *delta_truesize)
3369{
3370 int i, delta, len = from->len;
3371
3372 *fragstolen = false;
3373
3374 if (skb_cloned(to))
3375 return false;
3376
3377 if (len <= skb_tailroom(to)) {
3378 BUG_ON(skb_copy_bits(from, 0, skb_put(to, len), len));
3379 *delta_truesize = 0;
3380 return true;
3381 }
3382
3383 if (skb_has_frag_list(to) || skb_has_frag_list(from))
3384 return false;
3385
3386 if (skb_headlen(from) != 0) {
3387 struct page *page;
3388 unsigned int offset;
3389
3390 if (skb_shinfo(to)->nr_frags +
3391 skb_shinfo(from)->nr_frags >= MAX_SKB_FRAGS)
3392 return false;
3393
3394 if (skb_head_is_locked(from))
3395 return false;
3396
3397 delta = from->truesize - SKB_DATA_ALIGN(sizeof(struct sk_buff));
3398
3399 page = virt_to_head_page(from->head);
3400 offset = from->data - (unsigned char *)page_address(page);
3401
3402 skb_fill_page_desc(to, skb_shinfo(to)->nr_frags,
3403 page, offset, skb_headlen(from));
3404 *fragstolen = true;
3405 } else {
3406 if (skb_shinfo(to)->nr_frags +
3407 skb_shinfo(from)->nr_frags > MAX_SKB_FRAGS)
3408 return false;
3409
3410 delta = from->truesize -
3411 SKB_TRUESIZE(skb_end_pointer(from) - from->head);
3412 }
3413
3414 WARN_ON_ONCE(delta < len);
3415
3416 memcpy(skb_shinfo(to)->frags + skb_shinfo(to)->nr_frags,
3417 skb_shinfo(from)->frags,
3418 skb_shinfo(from)->nr_frags * sizeof(skb_frag_t));
3419 skb_shinfo(to)->nr_frags += skb_shinfo(from)->nr_frags;
3420
3421 if (!skb_cloned(from))
3422 skb_shinfo(from)->nr_frags = 0;
3423
3424 /* if the skb is cloned this does nothing since we set nr_frags to 0 */
3425 for (i = 0; i < skb_shinfo(from)->nr_frags; i++)
3426 skb_frag_ref(from, i);
3427
3428 to->truesize += delta;
3429 to->len += len;
3430 to->data_len += len;
3431
3432 *delta_truesize = delta;
3433 return true;
3434}
3435EXPORT_SYMBOL(skb_try_coalesce);