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1/*
2 * Routines having to do with the 'struct sk_buff' memory handlers.
3 *
4 * Authors: Alan Cox <alan@lxorguk.ukuu.org.uk>
5 * Florian La Roche <rzsfl@rz.uni-sb.de>
6 *
7 * Fixes:
8 * Alan Cox : Fixed the worst of the load
9 * balancer bugs.
10 * Dave Platt : Interrupt stacking fix.
11 * Richard Kooijman : Timestamp fixes.
12 * Alan Cox : Changed buffer format.
13 * Alan Cox : destructor hook for AF_UNIX etc.
14 * Linus Torvalds : Better skb_clone.
15 * Alan Cox : Added skb_copy.
16 * Alan Cox : Added all the changed routines Linus
17 * only put in the headers
18 * Ray VanTassle : Fixed --skb->lock in free
19 * Alan Cox : skb_copy copy arp field
20 * Andi Kleen : slabified it.
21 * Robert Olsson : Removed skb_head_pool
22 *
23 * NOTE:
24 * The __skb_ routines should be called with interrupts
25 * disabled, or you better be *real* sure that the operation is atomic
26 * with respect to whatever list is being frobbed (e.g. via lock_sock()
27 * or via disabling bottom half handlers, etc).
28 *
29 * This program is free software; you can redistribute it and/or
30 * modify it under the terms of the GNU General Public License
31 * as published by the Free Software Foundation; either version
32 * 2 of the License, or (at your option) any later version.
33 */
34
35/*
36 * The functions in this file will not compile correctly with gcc 2.4.x
37 */
38
39#include <linux/module.h>
40#include <linux/types.h>
41#include <linux/kernel.h>
42#include <linux/kmemcheck.h>
43#include <linux/mm.h>
44#include <linux/interrupt.h>
45#include <linux/in.h>
46#include <linux/inet.h>
47#include <linux/slab.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
62#include <net/protocol.h>
63#include <net/dst.h>
64#include <net/sock.h>
65#include <net/checksum.h>
66#include <net/xfrm.h>
67
68#include <asm/uaccess.h>
69#include <asm/system.h>
70#include <trace/events/skb.h>
71
72#include "kmap_skb.h"
73
74static struct 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 printk(KERN_EMERG "skb_over_panic: text:%p len:%d put:%d head:%p "
124 "data:%p tail:%#lx end:%#lx dev:%s\n",
125 here, skb->len, sz, skb->head, skb->data,
126 (unsigned long)skb->tail, (unsigned long)skb->end,
127 skb->dev ? skb->dev->name : "<NULL>");
128 BUG();
129}
130
131/**
132 * skb_under_panic - private function
133 * @skb: buffer
134 * @sz: size
135 * @here: address
136 *
137 * Out of line support code for skb_push(). Not user callable.
138 */
139
140static void skb_under_panic(struct sk_buff *skb, int sz, void *here)
141{
142 printk(KERN_EMERG "skb_under_panic: text:%p len:%d put:%d head:%p "
143 "data:%p tail:%#lx end:%#lx dev:%s\n",
144 here, skb->len, sz, skb->head, skb->data,
145 (unsigned long)skb->tail, (unsigned long)skb->end,
146 skb->dev ? skb->dev->name : "<NULL>");
147 BUG();
148}
149
150/* Allocate a new skbuff. We do this ourselves so we can fill in a few
151 * 'private' fields and also do memory statistics to find all the
152 * [BEEP] leaks.
153 *
154 */
155
156/**
157 * __alloc_skb - allocate a network buffer
158 * @size: size to allocate
159 * @gfp_mask: allocation mask
160 * @fclone: allocate from fclone cache instead of head cache
161 * and allocate a cloned (child) skb
162 * @node: numa node to allocate memory on
163 *
164 * Allocate a new &sk_buff. The returned buffer has no headroom and a
165 * tail room of size bytes. The object has a reference count of one.
166 * The return is the buffer. On a failure the return is %NULL.
167 *
168 * Buffers may only be allocated from interrupts using a @gfp_mask of
169 * %GFP_ATOMIC.
170 */
171struct sk_buff *__alloc_skb(unsigned int size, gfp_t gfp_mask,
172 int fclone, int node)
173{
174 struct kmem_cache *cache;
175 struct skb_shared_info *shinfo;
176 struct sk_buff *skb;
177 u8 *data;
178
179 cache = fclone ? skbuff_fclone_cache : skbuff_head_cache;
180
181 /* Get the HEAD */
182 skb = kmem_cache_alloc_node(cache, gfp_mask & ~__GFP_DMA, node);
183 if (!skb)
184 goto out;
185 prefetchw(skb);
186
187 size = SKB_DATA_ALIGN(size);
188 data = kmalloc_node_track_caller(size + sizeof(struct skb_shared_info),
189 gfp_mask, node);
190 if (!data)
191 goto nodata;
192 prefetchw(data + size);
193
194 /*
195 * Only clear those fields we need to clear, not those that we will
196 * actually initialise below. Hence, don't put any more fields after
197 * the tail pointer in struct sk_buff!
198 */
199 memset(skb, 0, offsetof(struct sk_buff, tail));
200 skb->truesize = size + sizeof(struct sk_buff);
201 atomic_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#ifdef NET_SKBUFF_DATA_USES_OFFSET
207 skb->mac_header = ~0U;
208#endif
209
210 /* make sure we initialize shinfo sequentially */
211 shinfo = skb_shinfo(skb);
212 memset(shinfo, 0, offsetof(struct skb_shared_info, dataref));
213 atomic_set(&shinfo->dataref, 1);
214 kmemcheck_annotate_variable(shinfo->destructor_arg);
215
216 if (fclone) {
217 struct sk_buff *child = skb + 1;
218 atomic_t *fclone_ref = (atomic_t *) (child + 1);
219
220 kmemcheck_annotate_bitfield(child, flags1);
221 kmemcheck_annotate_bitfield(child, flags2);
222 skb->fclone = SKB_FCLONE_ORIG;
223 atomic_set(fclone_ref, 1);
224
225 child->fclone = SKB_FCLONE_UNAVAILABLE;
226 }
227out:
228 return skb;
229nodata:
230 kmem_cache_free(cache, skb);
231 skb = NULL;
232 goto out;
233}
234EXPORT_SYMBOL(__alloc_skb);
235
236/**
237 * __netdev_alloc_skb - allocate an skbuff for rx on a specific device
238 * @dev: network device to receive on
239 * @length: length to allocate
240 * @gfp_mask: get_free_pages mask, passed to alloc_skb
241 *
242 * Allocate a new &sk_buff and assign it a usage count of one. The
243 * buffer has unspecified headroom built in. Users should allocate
244 * the headroom they think they need without accounting for the
245 * built in space. The built in space is used for optimisations.
246 *
247 * %NULL is returned if there is no free memory.
248 */
249struct sk_buff *__netdev_alloc_skb(struct net_device *dev,
250 unsigned int length, gfp_t gfp_mask)
251{
252 struct sk_buff *skb;
253
254 skb = __alloc_skb(length + NET_SKB_PAD, gfp_mask, 0, NUMA_NO_NODE);
255 if (likely(skb)) {
256 skb_reserve(skb, NET_SKB_PAD);
257 skb->dev = dev;
258 }
259 return skb;
260}
261EXPORT_SYMBOL(__netdev_alloc_skb);
262
263void skb_add_rx_frag(struct sk_buff *skb, int i, struct page *page, int off,
264 int size)
265{
266 skb_fill_page_desc(skb, i, page, off, size);
267 skb->len += size;
268 skb->data_len += size;
269 skb->truesize += size;
270}
271EXPORT_SYMBOL(skb_add_rx_frag);
272
273/**
274 * dev_alloc_skb - allocate an skbuff for receiving
275 * @length: length to allocate
276 *
277 * Allocate a new &sk_buff and assign it a usage count of one. The
278 * buffer has unspecified headroom built in. Users should allocate
279 * the headroom they think they need without accounting for the
280 * built in space. The built in space is used for optimisations.
281 *
282 * %NULL is returned if there is no free memory. Although this function
283 * allocates memory it can be called from an interrupt.
284 */
285struct sk_buff *dev_alloc_skb(unsigned int length)
286{
287 /*
288 * There is more code here than it seems:
289 * __dev_alloc_skb is an inline
290 */
291 return __dev_alloc_skb(length, GFP_ATOMIC);
292}
293EXPORT_SYMBOL(dev_alloc_skb);
294
295static void skb_drop_list(struct sk_buff **listp)
296{
297 struct sk_buff *list = *listp;
298
299 *listp = NULL;
300
301 do {
302 struct sk_buff *this = list;
303 list = list->next;
304 kfree_skb(this);
305 } while (list);
306}
307
308static inline void skb_drop_fraglist(struct sk_buff *skb)
309{
310 skb_drop_list(&skb_shinfo(skb)->frag_list);
311}
312
313static void skb_clone_fraglist(struct sk_buff *skb)
314{
315 struct sk_buff *list;
316
317 skb_walk_frags(skb, list)
318 skb_get(list);
319}
320
321static void skb_release_data(struct sk_buff *skb)
322{
323 if (!skb->cloned ||
324 !atomic_sub_return(skb->nohdr ? (1 << SKB_DATAREF_SHIFT) + 1 : 1,
325 &skb_shinfo(skb)->dataref)) {
326 if (skb_shinfo(skb)->nr_frags) {
327 int i;
328 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
329 put_page(skb_shinfo(skb)->frags[i].page);
330 }
331
332 /*
333 * If skb buf is from userspace, we need to notify the caller
334 * the lower device DMA has done;
335 */
336 if (skb_shinfo(skb)->tx_flags & SKBTX_DEV_ZEROCOPY) {
337 struct ubuf_info *uarg;
338
339 uarg = skb_shinfo(skb)->destructor_arg;
340 if (uarg->callback)
341 uarg->callback(uarg);
342 }
343
344 if (skb_has_frag_list(skb))
345 skb_drop_fraglist(skb);
346
347 kfree(skb->head);
348 }
349}
350
351/*
352 * Free an skbuff by memory without cleaning the state.
353 */
354static void kfree_skbmem(struct sk_buff *skb)
355{
356 struct sk_buff *other;
357 atomic_t *fclone_ref;
358
359 switch (skb->fclone) {
360 case SKB_FCLONE_UNAVAILABLE:
361 kmem_cache_free(skbuff_head_cache, skb);
362 break;
363
364 case SKB_FCLONE_ORIG:
365 fclone_ref = (atomic_t *) (skb + 2);
366 if (atomic_dec_and_test(fclone_ref))
367 kmem_cache_free(skbuff_fclone_cache, skb);
368 break;
369
370 case SKB_FCLONE_CLONE:
371 fclone_ref = (atomic_t *) (skb + 1);
372 other = skb - 1;
373
374 /* The clone portion is available for
375 * fast-cloning again.
376 */
377 skb->fclone = SKB_FCLONE_UNAVAILABLE;
378
379 if (atomic_dec_and_test(fclone_ref))
380 kmem_cache_free(skbuff_fclone_cache, other);
381 break;
382 }
383}
384
385static void skb_release_head_state(struct sk_buff *skb)
386{
387 skb_dst_drop(skb);
388#ifdef CONFIG_XFRM
389 secpath_put(skb->sp);
390#endif
391 if (skb->destructor) {
392 WARN_ON(in_irq());
393 skb->destructor(skb);
394 }
395#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
396 nf_conntrack_put(skb->nfct);
397#endif
398#ifdef NET_SKBUFF_NF_DEFRAG_NEEDED
399 nf_conntrack_put_reasm(skb->nfct_reasm);
400#endif
401#ifdef CONFIG_BRIDGE_NETFILTER
402 nf_bridge_put(skb->nf_bridge);
403#endif
404/* XXX: IS this still necessary? - JHS */
405#ifdef CONFIG_NET_SCHED
406 skb->tc_index = 0;
407#ifdef CONFIG_NET_CLS_ACT
408 skb->tc_verd = 0;
409#endif
410#endif
411}
412
413/* Free everything but the sk_buff shell. */
414static void skb_release_all(struct sk_buff *skb)
415{
416 skb_release_head_state(skb);
417 skb_release_data(skb);
418}
419
420/**
421 * __kfree_skb - private function
422 * @skb: buffer
423 *
424 * Free an sk_buff. Release anything attached to the buffer.
425 * Clean the state. This is an internal helper function. Users should
426 * always call kfree_skb
427 */
428
429void __kfree_skb(struct sk_buff *skb)
430{
431 skb_release_all(skb);
432 kfree_skbmem(skb);
433}
434EXPORT_SYMBOL(__kfree_skb);
435
436/**
437 * kfree_skb - free an sk_buff
438 * @skb: buffer to free
439 *
440 * Drop a reference to the buffer and free it if the usage count has
441 * hit zero.
442 */
443void kfree_skb(struct sk_buff *skb)
444{
445 if (unlikely(!skb))
446 return;
447 if (likely(atomic_read(&skb->users) == 1))
448 smp_rmb();
449 else if (likely(!atomic_dec_and_test(&skb->users)))
450 return;
451 trace_kfree_skb(skb, __builtin_return_address(0));
452 __kfree_skb(skb);
453}
454EXPORT_SYMBOL(kfree_skb);
455
456/**
457 * consume_skb - free an skbuff
458 * @skb: buffer to free
459 *
460 * Drop a ref to the buffer and free it if the usage count has hit zero
461 * Functions identically to kfree_skb, but kfree_skb assumes that the frame
462 * is being dropped after a failure and notes that
463 */
464void consume_skb(struct sk_buff *skb)
465{
466 if (unlikely(!skb))
467 return;
468 if (likely(atomic_read(&skb->users) == 1))
469 smp_rmb();
470 else if (likely(!atomic_dec_and_test(&skb->users)))
471 return;
472 trace_consume_skb(skb);
473 __kfree_skb(skb);
474}
475EXPORT_SYMBOL(consume_skb);
476
477/**
478 * skb_recycle_check - check if skb can be reused for receive
479 * @skb: buffer
480 * @skb_size: minimum receive buffer size
481 *
482 * Checks that the skb passed in is not shared or cloned, and
483 * that it is linear and its head portion at least as large as
484 * skb_size so that it can be recycled as a receive buffer.
485 * If these conditions are met, this function does any necessary
486 * reference count dropping and cleans up the skbuff as if it
487 * just came from __alloc_skb().
488 */
489bool skb_recycle_check(struct sk_buff *skb, int skb_size)
490{
491 struct skb_shared_info *shinfo;
492
493 if (irqs_disabled())
494 return false;
495
496 if (skb_shinfo(skb)->tx_flags & SKBTX_DEV_ZEROCOPY)
497 return false;
498
499 if (skb_is_nonlinear(skb) || skb->fclone != SKB_FCLONE_UNAVAILABLE)
500 return false;
501
502 skb_size = SKB_DATA_ALIGN(skb_size + NET_SKB_PAD);
503 if (skb_end_pointer(skb) - skb->head < skb_size)
504 return false;
505
506 if (skb_shared(skb) || skb_cloned(skb))
507 return false;
508
509 skb_release_head_state(skb);
510
511 shinfo = skb_shinfo(skb);
512 memset(shinfo, 0, offsetof(struct skb_shared_info, dataref));
513 atomic_set(&shinfo->dataref, 1);
514
515 memset(skb, 0, offsetof(struct sk_buff, tail));
516 skb->data = skb->head + NET_SKB_PAD;
517 skb_reset_tail_pointer(skb);
518
519 return true;
520}
521EXPORT_SYMBOL(skb_recycle_check);
522
523static void __copy_skb_header(struct sk_buff *new, const struct sk_buff *old)
524{
525 new->tstamp = old->tstamp;
526 new->dev = old->dev;
527 new->transport_header = old->transport_header;
528 new->network_header = old->network_header;
529 new->mac_header = old->mac_header;
530 skb_dst_copy(new, old);
531 new->rxhash = old->rxhash;
532#ifdef CONFIG_XFRM
533 new->sp = secpath_get(old->sp);
534#endif
535 memcpy(new->cb, old->cb, sizeof(old->cb));
536 new->csum = old->csum;
537 new->local_df = old->local_df;
538 new->pkt_type = old->pkt_type;
539 new->ip_summed = old->ip_summed;
540 skb_copy_queue_mapping(new, old);
541 new->priority = old->priority;
542#if defined(CONFIG_IP_VS) || defined(CONFIG_IP_VS_MODULE)
543 new->ipvs_property = old->ipvs_property;
544#endif
545 new->protocol = old->protocol;
546 new->mark = old->mark;
547 new->skb_iif = old->skb_iif;
548 __nf_copy(new, old);
549#if defined(CONFIG_NETFILTER_XT_TARGET_TRACE) || \
550 defined(CONFIG_NETFILTER_XT_TARGET_TRACE_MODULE)
551 new->nf_trace = old->nf_trace;
552#endif
553#ifdef CONFIG_NET_SCHED
554 new->tc_index = old->tc_index;
555#ifdef CONFIG_NET_CLS_ACT
556 new->tc_verd = old->tc_verd;
557#endif
558#endif
559 new->vlan_tci = old->vlan_tci;
560
561 skb_copy_secmark(new, old);
562}
563
564/*
565 * You should not add any new code to this function. Add it to
566 * __copy_skb_header above instead.
567 */
568static struct sk_buff *__skb_clone(struct sk_buff *n, struct sk_buff *skb)
569{
570#define C(x) n->x = skb->x
571
572 n->next = n->prev = NULL;
573 n->sk = NULL;
574 __copy_skb_header(n, skb);
575
576 C(len);
577 C(data_len);
578 C(mac_len);
579 n->hdr_len = skb->nohdr ? skb_headroom(skb) : skb->hdr_len;
580 n->cloned = 1;
581 n->nohdr = 0;
582 n->destructor = NULL;
583 C(tail);
584 C(end);
585 C(head);
586 C(data);
587 C(truesize);
588 atomic_set(&n->users, 1);
589
590 atomic_inc(&(skb_shinfo(skb)->dataref));
591 skb->cloned = 1;
592
593 return n;
594#undef C
595}
596
597/**
598 * skb_morph - morph one skb into another
599 * @dst: the skb to receive the contents
600 * @src: the skb to supply the contents
601 *
602 * This is identical to skb_clone except that the target skb is
603 * supplied by the user.
604 *
605 * The target skb is returned upon exit.
606 */
607struct sk_buff *skb_morph(struct sk_buff *dst, struct sk_buff *src)
608{
609 skb_release_all(dst);
610 return __skb_clone(dst, src);
611}
612EXPORT_SYMBOL_GPL(skb_morph);
613
614/* skb_copy_ubufs - copy userspace skb frags buffers to kernel
615 * @skb: the skb to modify
616 * @gfp_mask: allocation priority
617 *
618 * This must be called on SKBTX_DEV_ZEROCOPY skb.
619 * It will copy all frags into kernel and drop the reference
620 * to userspace pages.
621 *
622 * If this function is called from an interrupt gfp_mask() must be
623 * %GFP_ATOMIC.
624 *
625 * Returns 0 on success or a negative error code on failure
626 * to allocate kernel memory to copy to.
627 */
628int skb_copy_ubufs(struct sk_buff *skb, gfp_t gfp_mask)
629{
630 int i;
631 int num_frags = skb_shinfo(skb)->nr_frags;
632 struct page *page, *head = NULL;
633 struct ubuf_info *uarg = skb_shinfo(skb)->destructor_arg;
634
635 for (i = 0; i < num_frags; i++) {
636 u8 *vaddr;
637 skb_frag_t *f = &skb_shinfo(skb)->frags[i];
638
639 page = alloc_page(GFP_ATOMIC);
640 if (!page) {
641 while (head) {
642 struct page *next = (struct page *)head->private;
643 put_page(head);
644 head = next;
645 }
646 return -ENOMEM;
647 }
648 vaddr = kmap_skb_frag(&skb_shinfo(skb)->frags[i]);
649 memcpy(page_address(page),
650 vaddr + f->page_offset, f->size);
651 kunmap_skb_frag(vaddr);
652 page->private = (unsigned long)head;
653 head = page;
654 }
655
656 /* skb frags release userspace buffers */
657 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
658 put_page(skb_shinfo(skb)->frags[i].page);
659
660 uarg->callback(uarg);
661
662 /* skb frags point to kernel buffers */
663 for (i = skb_shinfo(skb)->nr_frags; i > 0; i--) {
664 skb_shinfo(skb)->frags[i - 1].page_offset = 0;
665 skb_shinfo(skb)->frags[i - 1].page = head;
666 head = (struct page *)head->private;
667 }
668
669 skb_shinfo(skb)->tx_flags &= ~SKBTX_DEV_ZEROCOPY;
670 return 0;
671}
672
673
674/**
675 * skb_clone - duplicate an sk_buff
676 * @skb: buffer to clone
677 * @gfp_mask: allocation priority
678 *
679 * Duplicate an &sk_buff. The new one is not owned by a socket. Both
680 * copies share the same packet data but not structure. The new
681 * buffer has a reference count of 1. If the allocation fails the
682 * function returns %NULL otherwise the new buffer is returned.
683 *
684 * If this function is called from an interrupt gfp_mask() must be
685 * %GFP_ATOMIC.
686 */
687
688struct sk_buff *skb_clone(struct sk_buff *skb, gfp_t gfp_mask)
689{
690 struct sk_buff *n;
691
692 if (skb_shinfo(skb)->tx_flags & SKBTX_DEV_ZEROCOPY) {
693 if (skb_copy_ubufs(skb, gfp_mask))
694 return NULL;
695 }
696
697 n = skb + 1;
698 if (skb->fclone == SKB_FCLONE_ORIG &&
699 n->fclone == SKB_FCLONE_UNAVAILABLE) {
700 atomic_t *fclone_ref = (atomic_t *) (n + 1);
701 n->fclone = SKB_FCLONE_CLONE;
702 atomic_inc(fclone_ref);
703 } else {
704 n = kmem_cache_alloc(skbuff_head_cache, gfp_mask);
705 if (!n)
706 return NULL;
707
708 kmemcheck_annotate_bitfield(n, flags1);
709 kmemcheck_annotate_bitfield(n, flags2);
710 n->fclone = SKB_FCLONE_UNAVAILABLE;
711 }
712
713 return __skb_clone(n, skb);
714}
715EXPORT_SYMBOL(skb_clone);
716
717static void copy_skb_header(struct sk_buff *new, const struct sk_buff *old)
718{
719#ifndef NET_SKBUFF_DATA_USES_OFFSET
720 /*
721 * Shift between the two data areas in bytes
722 */
723 unsigned long offset = new->data - old->data;
724#endif
725
726 __copy_skb_header(new, old);
727
728#ifndef NET_SKBUFF_DATA_USES_OFFSET
729 /* {transport,network,mac}_header are relative to skb->head */
730 new->transport_header += offset;
731 new->network_header += offset;
732 if (skb_mac_header_was_set(new))
733 new->mac_header += offset;
734#endif
735 skb_shinfo(new)->gso_size = skb_shinfo(old)->gso_size;
736 skb_shinfo(new)->gso_segs = skb_shinfo(old)->gso_segs;
737 skb_shinfo(new)->gso_type = skb_shinfo(old)->gso_type;
738}
739
740/**
741 * skb_copy - create private copy of an sk_buff
742 * @skb: buffer to copy
743 * @gfp_mask: allocation priority
744 *
745 * Make a copy of both an &sk_buff and its data. This is used when the
746 * caller wishes to modify the data and needs a private copy of the
747 * data to alter. Returns %NULL on failure or the pointer to the buffer
748 * on success. The returned buffer has a reference count of 1.
749 *
750 * As by-product this function converts non-linear &sk_buff to linear
751 * one, so that &sk_buff becomes completely private and caller is allowed
752 * to modify all the data of returned buffer. This means that this
753 * function is not recommended for use in circumstances when only
754 * header is going to be modified. Use pskb_copy() instead.
755 */
756
757struct sk_buff *skb_copy(const struct sk_buff *skb, gfp_t gfp_mask)
758{
759 int headerlen = skb_headroom(skb);
760 unsigned int size = (skb_end_pointer(skb) - skb->head) + skb->data_len;
761 struct sk_buff *n = alloc_skb(size, gfp_mask);
762
763 if (!n)
764 return NULL;
765
766 /* Set the data pointer */
767 skb_reserve(n, headerlen);
768 /* Set the tail pointer and length */
769 skb_put(n, skb->len);
770
771 if (skb_copy_bits(skb, -headerlen, n->head, headerlen + skb->len))
772 BUG();
773
774 copy_skb_header(n, skb);
775 return n;
776}
777EXPORT_SYMBOL(skb_copy);
778
779/**
780 * pskb_copy - create copy of an sk_buff with private head.
781 * @skb: buffer to copy
782 * @gfp_mask: allocation priority
783 *
784 * Make a copy of both an &sk_buff and part of its data, located
785 * in header. Fragmented data remain shared. This is used when
786 * the caller wishes to modify only header of &sk_buff and needs
787 * private copy of the header to alter. Returns %NULL on failure
788 * or the pointer to the buffer on success.
789 * The returned buffer has a reference count of 1.
790 */
791
792struct sk_buff *pskb_copy(struct sk_buff *skb, gfp_t gfp_mask)
793{
794 unsigned int size = skb_end_pointer(skb) - skb->head;
795 struct sk_buff *n = alloc_skb(size, gfp_mask);
796
797 if (!n)
798 goto out;
799
800 /* Set the data pointer */
801 skb_reserve(n, skb_headroom(skb));
802 /* Set the tail pointer and length */
803 skb_put(n, skb_headlen(skb));
804 /* Copy the bytes */
805 skb_copy_from_linear_data(skb, n->data, n->len);
806
807 n->truesize += skb->data_len;
808 n->data_len = skb->data_len;
809 n->len = skb->len;
810
811 if (skb_shinfo(skb)->nr_frags) {
812 int i;
813
814 if (skb_shinfo(skb)->tx_flags & SKBTX_DEV_ZEROCOPY) {
815 if (skb_copy_ubufs(skb, gfp_mask)) {
816 kfree_skb(n);
817 n = NULL;
818 goto out;
819 }
820 }
821 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
822 skb_shinfo(n)->frags[i] = skb_shinfo(skb)->frags[i];
823 get_page(skb_shinfo(n)->frags[i].page);
824 }
825 skb_shinfo(n)->nr_frags = i;
826 }
827
828 if (skb_has_frag_list(skb)) {
829 skb_shinfo(n)->frag_list = skb_shinfo(skb)->frag_list;
830 skb_clone_fraglist(n);
831 }
832
833 copy_skb_header(n, skb);
834out:
835 return n;
836}
837EXPORT_SYMBOL(pskb_copy);
838
839/**
840 * pskb_expand_head - reallocate header of &sk_buff
841 * @skb: buffer to reallocate
842 * @nhead: room to add at head
843 * @ntail: room to add at tail
844 * @gfp_mask: allocation priority
845 *
846 * Expands (or creates identical copy, if &nhead and &ntail are zero)
847 * header of skb. &sk_buff itself is not changed. &sk_buff MUST have
848 * reference count of 1. Returns zero in the case of success or error,
849 * if expansion failed. In the last case, &sk_buff is not changed.
850 *
851 * All the pointers pointing into skb header may change and must be
852 * reloaded after call to this function.
853 */
854
855int pskb_expand_head(struct sk_buff *skb, int nhead, int ntail,
856 gfp_t gfp_mask)
857{
858 int i;
859 u8 *data;
860 int size = nhead + (skb_end_pointer(skb) - skb->head) + ntail;
861 long off;
862 bool fastpath;
863
864 BUG_ON(nhead < 0);
865
866 if (skb_shared(skb))
867 BUG();
868
869 size = SKB_DATA_ALIGN(size);
870
871 /* Check if we can avoid taking references on fragments if we own
872 * the last reference on skb->head. (see skb_release_data())
873 */
874 if (!skb->cloned)
875 fastpath = true;
876 else {
877 int delta = skb->nohdr ? (1 << SKB_DATAREF_SHIFT) + 1 : 1;
878 fastpath = atomic_read(&skb_shinfo(skb)->dataref) == delta;
879 }
880
881 if (fastpath &&
882 size + sizeof(struct skb_shared_info) <= ksize(skb->head)) {
883 memmove(skb->head + size, skb_shinfo(skb),
884 offsetof(struct skb_shared_info,
885 frags[skb_shinfo(skb)->nr_frags]));
886 memmove(skb->head + nhead, skb->head,
887 skb_tail_pointer(skb) - skb->head);
888 off = nhead;
889 goto adjust_others;
890 }
891
892 data = kmalloc(size + sizeof(struct skb_shared_info), gfp_mask);
893 if (!data)
894 goto nodata;
895
896 /* Copy only real data... and, alas, header. This should be
897 * optimized for the cases when header is void.
898 */
899 memcpy(data + nhead, skb->head, skb_tail_pointer(skb) - skb->head);
900
901 memcpy((struct skb_shared_info *)(data + size),
902 skb_shinfo(skb),
903 offsetof(struct skb_shared_info, frags[skb_shinfo(skb)->nr_frags]));
904
905 if (fastpath) {
906 kfree(skb->head);
907 } else {
908 /* copy this zero copy skb frags */
909 if (skb_shinfo(skb)->tx_flags & SKBTX_DEV_ZEROCOPY) {
910 if (skb_copy_ubufs(skb, gfp_mask))
911 goto nofrags;
912 }
913 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
914 get_page(skb_shinfo(skb)->frags[i].page);
915
916 if (skb_has_frag_list(skb))
917 skb_clone_fraglist(skb);
918
919 skb_release_data(skb);
920 }
921 off = (data + nhead) - skb->head;
922
923 skb->head = data;
924adjust_others:
925 skb->data += off;
926#ifdef NET_SKBUFF_DATA_USES_OFFSET
927 skb->end = size;
928 off = nhead;
929#else
930 skb->end = skb->head + size;
931#endif
932 /* {transport,network,mac}_header and tail are relative to skb->head */
933 skb->tail += off;
934 skb->transport_header += off;
935 skb->network_header += off;
936 if (skb_mac_header_was_set(skb))
937 skb->mac_header += off;
938 /* Only adjust this if it actually is csum_start rather than csum */
939 if (skb->ip_summed == CHECKSUM_PARTIAL)
940 skb->csum_start += nhead;
941 skb->cloned = 0;
942 skb->hdr_len = 0;
943 skb->nohdr = 0;
944 atomic_set(&skb_shinfo(skb)->dataref, 1);
945 return 0;
946
947nofrags:
948 kfree(data);
949nodata:
950 return -ENOMEM;
951}
952EXPORT_SYMBOL(pskb_expand_head);
953
954/* Make private copy of skb with writable head and some headroom */
955
956struct sk_buff *skb_realloc_headroom(struct sk_buff *skb, unsigned int headroom)
957{
958 struct sk_buff *skb2;
959 int delta = headroom - skb_headroom(skb);
960
961 if (delta <= 0)
962 skb2 = pskb_copy(skb, GFP_ATOMIC);
963 else {
964 skb2 = skb_clone(skb, GFP_ATOMIC);
965 if (skb2 && pskb_expand_head(skb2, SKB_DATA_ALIGN(delta), 0,
966 GFP_ATOMIC)) {
967 kfree_skb(skb2);
968 skb2 = NULL;
969 }
970 }
971 return skb2;
972}
973EXPORT_SYMBOL(skb_realloc_headroom);
974
975/**
976 * skb_copy_expand - copy and expand sk_buff
977 * @skb: buffer to copy
978 * @newheadroom: new free bytes at head
979 * @newtailroom: new free bytes at tail
980 * @gfp_mask: allocation priority
981 *
982 * Make a copy of both an &sk_buff and its data and while doing so
983 * allocate additional space.
984 *
985 * This is used when the caller wishes to modify the data and needs a
986 * private copy of the data to alter as well as more space for new fields.
987 * Returns %NULL on failure or the pointer to the buffer
988 * on success. The returned buffer has a reference count of 1.
989 *
990 * You must pass %GFP_ATOMIC as the allocation priority if this function
991 * is called from an interrupt.
992 */
993struct sk_buff *skb_copy_expand(const struct sk_buff *skb,
994 int newheadroom, int newtailroom,
995 gfp_t gfp_mask)
996{
997 /*
998 * Allocate the copy buffer
999 */
1000 struct sk_buff *n = alloc_skb(newheadroom + skb->len + newtailroom,
1001 gfp_mask);
1002 int oldheadroom = skb_headroom(skb);
1003 int head_copy_len, head_copy_off;
1004 int off;
1005
1006 if (!n)
1007 return NULL;
1008
1009 skb_reserve(n, newheadroom);
1010
1011 /* Set the tail pointer and length */
1012 skb_put(n, skb->len);
1013
1014 head_copy_len = oldheadroom;
1015 head_copy_off = 0;
1016 if (newheadroom <= head_copy_len)
1017 head_copy_len = newheadroom;
1018 else
1019 head_copy_off = newheadroom - head_copy_len;
1020
1021 /* Copy the linear header and data. */
1022 if (skb_copy_bits(skb, -head_copy_len, n->head + head_copy_off,
1023 skb->len + head_copy_len))
1024 BUG();
1025
1026 copy_skb_header(n, skb);
1027
1028 off = newheadroom - oldheadroom;
1029 if (n->ip_summed == CHECKSUM_PARTIAL)
1030 n->csum_start += off;
1031#ifdef NET_SKBUFF_DATA_USES_OFFSET
1032 n->transport_header += off;
1033 n->network_header += off;
1034 if (skb_mac_header_was_set(skb))
1035 n->mac_header += off;
1036#endif
1037
1038 return n;
1039}
1040EXPORT_SYMBOL(skb_copy_expand);
1041
1042/**
1043 * skb_pad - zero pad the tail of an skb
1044 * @skb: buffer to pad
1045 * @pad: space to pad
1046 *
1047 * Ensure that a buffer is followed by a padding area that is zero
1048 * filled. Used by network drivers which may DMA or transfer data
1049 * beyond the buffer end onto the wire.
1050 *
1051 * May return error in out of memory cases. The skb is freed on error.
1052 */
1053
1054int skb_pad(struct sk_buff *skb, int pad)
1055{
1056 int err;
1057 int ntail;
1058
1059 /* If the skbuff is non linear tailroom is always zero.. */
1060 if (!skb_cloned(skb) && skb_tailroom(skb) >= pad) {
1061 memset(skb->data+skb->len, 0, pad);
1062 return 0;
1063 }
1064
1065 ntail = skb->data_len + pad - (skb->end - skb->tail);
1066 if (likely(skb_cloned(skb) || ntail > 0)) {
1067 err = pskb_expand_head(skb, 0, ntail, GFP_ATOMIC);
1068 if (unlikely(err))
1069 goto free_skb;
1070 }
1071
1072 /* FIXME: The use of this function with non-linear skb's really needs
1073 * to be audited.
1074 */
1075 err = skb_linearize(skb);
1076 if (unlikely(err))
1077 goto free_skb;
1078
1079 memset(skb->data + skb->len, 0, pad);
1080 return 0;
1081
1082free_skb:
1083 kfree_skb(skb);
1084 return err;
1085}
1086EXPORT_SYMBOL(skb_pad);
1087
1088/**
1089 * skb_put - add data to a buffer
1090 * @skb: buffer to use
1091 * @len: amount of data to add
1092 *
1093 * This function extends the used data area of the buffer. If this would
1094 * exceed the total buffer size the kernel will panic. A pointer to the
1095 * first byte of the extra data is returned.
1096 */
1097unsigned char *skb_put(struct sk_buff *skb, unsigned int len)
1098{
1099 unsigned char *tmp = skb_tail_pointer(skb);
1100 SKB_LINEAR_ASSERT(skb);
1101 skb->tail += len;
1102 skb->len += len;
1103 if (unlikely(skb->tail > skb->end))
1104 skb_over_panic(skb, len, __builtin_return_address(0));
1105 return tmp;
1106}
1107EXPORT_SYMBOL(skb_put);
1108
1109/**
1110 * skb_push - add data to the start of a buffer
1111 * @skb: buffer to use
1112 * @len: amount of data to add
1113 *
1114 * This function extends the used data area of the buffer at the buffer
1115 * start. If this would exceed the total buffer headroom the kernel will
1116 * panic. A pointer to the first byte of the extra data is returned.
1117 */
1118unsigned char *skb_push(struct sk_buff *skb, unsigned int len)
1119{
1120 skb->data -= len;
1121 skb->len += len;
1122 if (unlikely(skb->data<skb->head))
1123 skb_under_panic(skb, len, __builtin_return_address(0));
1124 return skb->data;
1125}
1126EXPORT_SYMBOL(skb_push);
1127
1128/**
1129 * skb_pull - remove data from the start of a buffer
1130 * @skb: buffer to use
1131 * @len: amount of data to remove
1132 *
1133 * This function removes data from the start of a buffer, returning
1134 * the memory to the headroom. A pointer to the next data in the buffer
1135 * is returned. Once the data has been pulled future pushes will overwrite
1136 * the old data.
1137 */
1138unsigned char *skb_pull(struct sk_buff *skb, unsigned int len)
1139{
1140 return skb_pull_inline(skb, len);
1141}
1142EXPORT_SYMBOL(skb_pull);
1143
1144/**
1145 * skb_trim - remove end from a buffer
1146 * @skb: buffer to alter
1147 * @len: new length
1148 *
1149 * Cut the length of a buffer down by removing data from the tail. If
1150 * the buffer is already under the length specified it is not modified.
1151 * The skb must be linear.
1152 */
1153void skb_trim(struct sk_buff *skb, unsigned int len)
1154{
1155 if (skb->len > len)
1156 __skb_trim(skb, len);
1157}
1158EXPORT_SYMBOL(skb_trim);
1159
1160/* Trims skb to length len. It can change skb pointers.
1161 */
1162
1163int ___pskb_trim(struct sk_buff *skb, unsigned int len)
1164{
1165 struct sk_buff **fragp;
1166 struct sk_buff *frag;
1167 int offset = skb_headlen(skb);
1168 int nfrags = skb_shinfo(skb)->nr_frags;
1169 int i;
1170 int err;
1171
1172 if (skb_cloned(skb) &&
1173 unlikely((err = pskb_expand_head(skb, 0, 0, GFP_ATOMIC))))
1174 return err;
1175
1176 i = 0;
1177 if (offset >= len)
1178 goto drop_pages;
1179
1180 for (; i < nfrags; i++) {
1181 int end = offset + skb_shinfo(skb)->frags[i].size;
1182
1183 if (end < len) {
1184 offset = end;
1185 continue;
1186 }
1187
1188 skb_shinfo(skb)->frags[i++].size = len - offset;
1189
1190drop_pages:
1191 skb_shinfo(skb)->nr_frags = i;
1192
1193 for (; i < nfrags; i++)
1194 put_page(skb_shinfo(skb)->frags[i].page);
1195
1196 if (skb_has_frag_list(skb))
1197 skb_drop_fraglist(skb);
1198 goto done;
1199 }
1200
1201 for (fragp = &skb_shinfo(skb)->frag_list; (frag = *fragp);
1202 fragp = &frag->next) {
1203 int end = offset + frag->len;
1204
1205 if (skb_shared(frag)) {
1206 struct sk_buff *nfrag;
1207
1208 nfrag = skb_clone(frag, GFP_ATOMIC);
1209 if (unlikely(!nfrag))
1210 return -ENOMEM;
1211
1212 nfrag->next = frag->next;
1213 kfree_skb(frag);
1214 frag = nfrag;
1215 *fragp = frag;
1216 }
1217
1218 if (end < len) {
1219 offset = end;
1220 continue;
1221 }
1222
1223 if (end > len &&
1224 unlikely((err = pskb_trim(frag, len - offset))))
1225 return err;
1226
1227 if (frag->next)
1228 skb_drop_list(&frag->next);
1229 break;
1230 }
1231
1232done:
1233 if (len > skb_headlen(skb)) {
1234 skb->data_len -= skb->len - len;
1235 skb->len = len;
1236 } else {
1237 skb->len = len;
1238 skb->data_len = 0;
1239 skb_set_tail_pointer(skb, len);
1240 }
1241
1242 return 0;
1243}
1244EXPORT_SYMBOL(___pskb_trim);
1245
1246/**
1247 * __pskb_pull_tail - advance tail of skb header
1248 * @skb: buffer to reallocate
1249 * @delta: number of bytes to advance tail
1250 *
1251 * The function makes a sense only on a fragmented &sk_buff,
1252 * it expands header moving its tail forward and copying necessary
1253 * data from fragmented part.
1254 *
1255 * &sk_buff MUST have reference count of 1.
1256 *
1257 * Returns %NULL (and &sk_buff does not change) if pull failed
1258 * or value of new tail of skb in the case of success.
1259 *
1260 * All the pointers pointing into skb header may change and must be
1261 * reloaded after call to this function.
1262 */
1263
1264/* Moves tail of skb head forward, copying data from fragmented part,
1265 * when it is necessary.
1266 * 1. It may fail due to malloc failure.
1267 * 2. It may change skb pointers.
1268 *
1269 * It is pretty complicated. Luckily, it is called only in exceptional cases.
1270 */
1271unsigned char *__pskb_pull_tail(struct sk_buff *skb, int delta)
1272{
1273 /* If skb has not enough free space at tail, get new one
1274 * plus 128 bytes for future expansions. If we have enough
1275 * room at tail, reallocate without expansion only if skb is cloned.
1276 */
1277 int i, k, eat = (skb->tail + delta) - skb->end;
1278
1279 if (eat > 0 || skb_cloned(skb)) {
1280 if (pskb_expand_head(skb, 0, eat > 0 ? eat + 128 : 0,
1281 GFP_ATOMIC))
1282 return NULL;
1283 }
1284
1285 if (skb_copy_bits(skb, skb_headlen(skb), skb_tail_pointer(skb), delta))
1286 BUG();
1287
1288 /* Optimization: no fragments, no reasons to preestimate
1289 * size of pulled pages. Superb.
1290 */
1291 if (!skb_has_frag_list(skb))
1292 goto pull_pages;
1293
1294 /* Estimate size of pulled pages. */
1295 eat = delta;
1296 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
1297 if (skb_shinfo(skb)->frags[i].size >= eat)
1298 goto pull_pages;
1299 eat -= skb_shinfo(skb)->frags[i].size;
1300 }
1301
1302 /* If we need update frag list, we are in troubles.
1303 * Certainly, it possible to add an offset to skb data,
1304 * but taking into account that pulling is expected to
1305 * be very rare operation, it is worth to fight against
1306 * further bloating skb head and crucify ourselves here instead.
1307 * Pure masohism, indeed. 8)8)
1308 */
1309 if (eat) {
1310 struct sk_buff *list = skb_shinfo(skb)->frag_list;
1311 struct sk_buff *clone = NULL;
1312 struct sk_buff *insp = NULL;
1313
1314 do {
1315 BUG_ON(!list);
1316
1317 if (list->len <= eat) {
1318 /* Eaten as whole. */
1319 eat -= list->len;
1320 list = list->next;
1321 insp = list;
1322 } else {
1323 /* Eaten partially. */
1324
1325 if (skb_shared(list)) {
1326 /* Sucks! We need to fork list. :-( */
1327 clone = skb_clone(list, GFP_ATOMIC);
1328 if (!clone)
1329 return NULL;
1330 insp = list->next;
1331 list = clone;
1332 } else {
1333 /* This may be pulled without
1334 * problems. */
1335 insp = list;
1336 }
1337 if (!pskb_pull(list, eat)) {
1338 kfree_skb(clone);
1339 return NULL;
1340 }
1341 break;
1342 }
1343 } while (eat);
1344
1345 /* Free pulled out fragments. */
1346 while ((list = skb_shinfo(skb)->frag_list) != insp) {
1347 skb_shinfo(skb)->frag_list = list->next;
1348 kfree_skb(list);
1349 }
1350 /* And insert new clone at head. */
1351 if (clone) {
1352 clone->next = list;
1353 skb_shinfo(skb)->frag_list = clone;
1354 }
1355 }
1356 /* Success! Now we may commit changes to skb data. */
1357
1358pull_pages:
1359 eat = delta;
1360 k = 0;
1361 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
1362 if (skb_shinfo(skb)->frags[i].size <= eat) {
1363 put_page(skb_shinfo(skb)->frags[i].page);
1364 eat -= skb_shinfo(skb)->frags[i].size;
1365 } else {
1366 skb_shinfo(skb)->frags[k] = skb_shinfo(skb)->frags[i];
1367 if (eat) {
1368 skb_shinfo(skb)->frags[k].page_offset += eat;
1369 skb_shinfo(skb)->frags[k].size -= eat;
1370 eat = 0;
1371 }
1372 k++;
1373 }
1374 }
1375 skb_shinfo(skb)->nr_frags = k;
1376
1377 skb->tail += delta;
1378 skb->data_len -= delta;
1379
1380 return skb_tail_pointer(skb);
1381}
1382EXPORT_SYMBOL(__pskb_pull_tail);
1383
1384/**
1385 * skb_copy_bits - copy bits from skb to kernel buffer
1386 * @skb: source skb
1387 * @offset: offset in source
1388 * @to: destination buffer
1389 * @len: number of bytes to copy
1390 *
1391 * Copy the specified number of bytes from the source skb to the
1392 * destination buffer.
1393 *
1394 * CAUTION ! :
1395 * If its prototype is ever changed,
1396 * check arch/{*}/net/{*}.S files,
1397 * since it is called from BPF assembly code.
1398 */
1399int skb_copy_bits(const struct sk_buff *skb, int offset, void *to, int len)
1400{
1401 int start = skb_headlen(skb);
1402 struct sk_buff *frag_iter;
1403 int i, copy;
1404
1405 if (offset > (int)skb->len - len)
1406 goto fault;
1407
1408 /* Copy header. */
1409 if ((copy = start - offset) > 0) {
1410 if (copy > len)
1411 copy = len;
1412 skb_copy_from_linear_data_offset(skb, offset, to, copy);
1413 if ((len -= copy) == 0)
1414 return 0;
1415 offset += copy;
1416 to += copy;
1417 }
1418
1419 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
1420 int end;
1421
1422 WARN_ON(start > offset + len);
1423
1424 end = start + skb_shinfo(skb)->frags[i].size;
1425 if ((copy = end - offset) > 0) {
1426 u8 *vaddr;
1427
1428 if (copy > len)
1429 copy = len;
1430
1431 vaddr = kmap_skb_frag(&skb_shinfo(skb)->frags[i]);
1432 memcpy(to,
1433 vaddr + skb_shinfo(skb)->frags[i].page_offset+
1434 offset - start, copy);
1435 kunmap_skb_frag(vaddr);
1436
1437 if ((len -= copy) == 0)
1438 return 0;
1439 offset += copy;
1440 to += copy;
1441 }
1442 start = end;
1443 }
1444
1445 skb_walk_frags(skb, frag_iter) {
1446 int end;
1447
1448 WARN_ON(start > offset + len);
1449
1450 end = start + frag_iter->len;
1451 if ((copy = end - offset) > 0) {
1452 if (copy > len)
1453 copy = len;
1454 if (skb_copy_bits(frag_iter, offset - start, to, copy))
1455 goto fault;
1456 if ((len -= copy) == 0)
1457 return 0;
1458 offset += copy;
1459 to += copy;
1460 }
1461 start = end;
1462 }
1463
1464 if (!len)
1465 return 0;
1466
1467fault:
1468 return -EFAULT;
1469}
1470EXPORT_SYMBOL(skb_copy_bits);
1471
1472/*
1473 * Callback from splice_to_pipe(), if we need to release some pages
1474 * at the end of the spd in case we error'ed out in filling the pipe.
1475 */
1476static void sock_spd_release(struct splice_pipe_desc *spd, unsigned int i)
1477{
1478 put_page(spd->pages[i]);
1479}
1480
1481static inline struct page *linear_to_page(struct page *page, unsigned int *len,
1482 unsigned int *offset,
1483 struct sk_buff *skb, struct sock *sk)
1484{
1485 struct page *p = sk->sk_sndmsg_page;
1486 unsigned int off;
1487
1488 if (!p) {
1489new_page:
1490 p = sk->sk_sndmsg_page = alloc_pages(sk->sk_allocation, 0);
1491 if (!p)
1492 return NULL;
1493
1494 off = sk->sk_sndmsg_off = 0;
1495 /* hold one ref to this page until it's full */
1496 } else {
1497 unsigned int mlen;
1498
1499 off = sk->sk_sndmsg_off;
1500 mlen = PAGE_SIZE - off;
1501 if (mlen < 64 && mlen < *len) {
1502 put_page(p);
1503 goto new_page;
1504 }
1505
1506 *len = min_t(unsigned int, *len, mlen);
1507 }
1508
1509 memcpy(page_address(p) + off, page_address(page) + *offset, *len);
1510 sk->sk_sndmsg_off += *len;
1511 *offset = off;
1512 get_page(p);
1513
1514 return p;
1515}
1516
1517/*
1518 * Fill page/offset/length into spd, if it can hold more pages.
1519 */
1520static inline int spd_fill_page(struct splice_pipe_desc *spd,
1521 struct pipe_inode_info *pipe, struct page *page,
1522 unsigned int *len, unsigned int offset,
1523 struct sk_buff *skb, int linear,
1524 struct sock *sk)
1525{
1526 if (unlikely(spd->nr_pages == pipe->buffers))
1527 return 1;
1528
1529 if (linear) {
1530 page = linear_to_page(page, len, &offset, skb, sk);
1531 if (!page)
1532 return 1;
1533 } else
1534 get_page(page);
1535
1536 spd->pages[spd->nr_pages] = page;
1537 spd->partial[spd->nr_pages].len = *len;
1538 spd->partial[spd->nr_pages].offset = offset;
1539 spd->nr_pages++;
1540
1541 return 0;
1542}
1543
1544static inline void __segment_seek(struct page **page, unsigned int *poff,
1545 unsigned int *plen, unsigned int off)
1546{
1547 unsigned long n;
1548
1549 *poff += off;
1550 n = *poff / PAGE_SIZE;
1551 if (n)
1552 *page = nth_page(*page, n);
1553
1554 *poff = *poff % PAGE_SIZE;
1555 *plen -= off;
1556}
1557
1558static inline int __splice_segment(struct page *page, unsigned int poff,
1559 unsigned int plen, unsigned int *off,
1560 unsigned int *len, struct sk_buff *skb,
1561 struct splice_pipe_desc *spd, int linear,
1562 struct sock *sk,
1563 struct pipe_inode_info *pipe)
1564{
1565 if (!*len)
1566 return 1;
1567
1568 /* skip this segment if already processed */
1569 if (*off >= plen) {
1570 *off -= plen;
1571 return 0;
1572 }
1573
1574 /* ignore any bits we already processed */
1575 if (*off) {
1576 __segment_seek(&page, &poff, &plen, *off);
1577 *off = 0;
1578 }
1579
1580 do {
1581 unsigned int flen = min(*len, plen);
1582
1583 /* the linear region may spread across several pages */
1584 flen = min_t(unsigned int, flen, PAGE_SIZE - poff);
1585
1586 if (spd_fill_page(spd, pipe, page, &flen, poff, skb, linear, sk))
1587 return 1;
1588
1589 __segment_seek(&page, &poff, &plen, flen);
1590 *len -= flen;
1591
1592 } while (*len && plen);
1593
1594 return 0;
1595}
1596
1597/*
1598 * Map linear and fragment data from the skb to spd. It reports failure if the
1599 * pipe is full or if we already spliced the requested length.
1600 */
1601static int __skb_splice_bits(struct sk_buff *skb, struct pipe_inode_info *pipe,
1602 unsigned int *offset, unsigned int *len,
1603 struct splice_pipe_desc *spd, struct sock *sk)
1604{
1605 int seg;
1606
1607 /*
1608 * map the linear part
1609 */
1610 if (__splice_segment(virt_to_page(skb->data),
1611 (unsigned long) skb->data & (PAGE_SIZE - 1),
1612 skb_headlen(skb),
1613 offset, len, skb, spd, 1, sk, pipe))
1614 return 1;
1615
1616 /*
1617 * then map the fragments
1618 */
1619 for (seg = 0; seg < skb_shinfo(skb)->nr_frags; seg++) {
1620 const skb_frag_t *f = &skb_shinfo(skb)->frags[seg];
1621
1622 if (__splice_segment(f->page, f->page_offset, f->size,
1623 offset, len, skb, spd, 0, sk, pipe))
1624 return 1;
1625 }
1626
1627 return 0;
1628}
1629
1630/*
1631 * Map data from the skb to a pipe. Should handle both the linear part,
1632 * the fragments, and the frag list. It does NOT handle frag lists within
1633 * the frag list, if such a thing exists. We'd probably need to recurse to
1634 * handle that cleanly.
1635 */
1636int skb_splice_bits(struct sk_buff *skb, unsigned int offset,
1637 struct pipe_inode_info *pipe, unsigned int tlen,
1638 unsigned int flags)
1639{
1640 struct partial_page partial[PIPE_DEF_BUFFERS];
1641 struct page *pages[PIPE_DEF_BUFFERS];
1642 struct splice_pipe_desc spd = {
1643 .pages = pages,
1644 .partial = partial,
1645 .flags = flags,
1646 .ops = &sock_pipe_buf_ops,
1647 .spd_release = sock_spd_release,
1648 };
1649 struct sk_buff *frag_iter;
1650 struct sock *sk = skb->sk;
1651 int ret = 0;
1652
1653 if (splice_grow_spd(pipe, &spd))
1654 return -ENOMEM;
1655
1656 /*
1657 * __skb_splice_bits() only fails if the output has no room left,
1658 * so no point in going over the frag_list for the error case.
1659 */
1660 if (__skb_splice_bits(skb, pipe, &offset, &tlen, &spd, sk))
1661 goto done;
1662 else if (!tlen)
1663 goto done;
1664
1665 /*
1666 * now see if we have a frag_list to map
1667 */
1668 skb_walk_frags(skb, frag_iter) {
1669 if (!tlen)
1670 break;
1671 if (__skb_splice_bits(frag_iter, pipe, &offset, &tlen, &spd, sk))
1672 break;
1673 }
1674
1675done:
1676 if (spd.nr_pages) {
1677 /*
1678 * Drop the socket lock, otherwise we have reverse
1679 * locking dependencies between sk_lock and i_mutex
1680 * here as compared to sendfile(). We enter here
1681 * with the socket lock held, and splice_to_pipe() will
1682 * grab the pipe inode lock. For sendfile() emulation,
1683 * we call into ->sendpage() with the i_mutex lock held
1684 * and networking will grab the socket lock.
1685 */
1686 release_sock(sk);
1687 ret = splice_to_pipe(pipe, &spd);
1688 lock_sock(sk);
1689 }
1690
1691 splice_shrink_spd(pipe, &spd);
1692 return ret;
1693}
1694
1695/**
1696 * skb_store_bits - store bits from kernel buffer to skb
1697 * @skb: destination buffer
1698 * @offset: offset in destination
1699 * @from: source buffer
1700 * @len: number of bytes to copy
1701 *
1702 * Copy the specified number of bytes from the source buffer to the
1703 * destination skb. This function handles all the messy bits of
1704 * traversing fragment lists and such.
1705 */
1706
1707int skb_store_bits(struct sk_buff *skb, int offset, const void *from, int len)
1708{
1709 int start = skb_headlen(skb);
1710 struct sk_buff *frag_iter;
1711 int i, copy;
1712
1713 if (offset > (int)skb->len - len)
1714 goto fault;
1715
1716 if ((copy = start - offset) > 0) {
1717 if (copy > len)
1718 copy = len;
1719 skb_copy_to_linear_data_offset(skb, offset, from, copy);
1720 if ((len -= copy) == 0)
1721 return 0;
1722 offset += copy;
1723 from += copy;
1724 }
1725
1726 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
1727 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
1728 int end;
1729
1730 WARN_ON(start > offset + len);
1731
1732 end = start + frag->size;
1733 if ((copy = end - offset) > 0) {
1734 u8 *vaddr;
1735
1736 if (copy > len)
1737 copy = len;
1738
1739 vaddr = kmap_skb_frag(frag);
1740 memcpy(vaddr + frag->page_offset + offset - start,
1741 from, copy);
1742 kunmap_skb_frag(vaddr);
1743
1744 if ((len -= copy) == 0)
1745 return 0;
1746 offset += copy;
1747 from += copy;
1748 }
1749 start = end;
1750 }
1751
1752 skb_walk_frags(skb, frag_iter) {
1753 int end;
1754
1755 WARN_ON(start > offset + len);
1756
1757 end = start + frag_iter->len;
1758 if ((copy = end - offset) > 0) {
1759 if (copy > len)
1760 copy = len;
1761 if (skb_store_bits(frag_iter, offset - start,
1762 from, copy))
1763 goto fault;
1764 if ((len -= copy) == 0)
1765 return 0;
1766 offset += copy;
1767 from += copy;
1768 }
1769 start = end;
1770 }
1771 if (!len)
1772 return 0;
1773
1774fault:
1775 return -EFAULT;
1776}
1777EXPORT_SYMBOL(skb_store_bits);
1778
1779/* Checksum skb data. */
1780
1781__wsum skb_checksum(const struct sk_buff *skb, int offset,
1782 int len, __wsum csum)
1783{
1784 int start = skb_headlen(skb);
1785 int i, copy = start - offset;
1786 struct sk_buff *frag_iter;
1787 int pos = 0;
1788
1789 /* Checksum header. */
1790 if (copy > 0) {
1791 if (copy > len)
1792 copy = len;
1793 csum = csum_partial(skb->data + offset, copy, csum);
1794 if ((len -= copy) == 0)
1795 return csum;
1796 offset += copy;
1797 pos = copy;
1798 }
1799
1800 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
1801 int end;
1802
1803 WARN_ON(start > offset + len);
1804
1805 end = start + skb_shinfo(skb)->frags[i].size;
1806 if ((copy = end - offset) > 0) {
1807 __wsum csum2;
1808 u8 *vaddr;
1809 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
1810
1811 if (copy > len)
1812 copy = len;
1813 vaddr = kmap_skb_frag(frag);
1814 csum2 = csum_partial(vaddr + frag->page_offset +
1815 offset - start, copy, 0);
1816 kunmap_skb_frag(vaddr);
1817 csum = csum_block_add(csum, csum2, pos);
1818 if (!(len -= copy))
1819 return csum;
1820 offset += copy;
1821 pos += copy;
1822 }
1823 start = end;
1824 }
1825
1826 skb_walk_frags(skb, frag_iter) {
1827 int end;
1828
1829 WARN_ON(start > offset + len);
1830
1831 end = start + frag_iter->len;
1832 if ((copy = end - offset) > 0) {
1833 __wsum csum2;
1834 if (copy > len)
1835 copy = len;
1836 csum2 = skb_checksum(frag_iter, offset - start,
1837 copy, 0);
1838 csum = csum_block_add(csum, csum2, pos);
1839 if ((len -= copy) == 0)
1840 return csum;
1841 offset += copy;
1842 pos += copy;
1843 }
1844 start = end;
1845 }
1846 BUG_ON(len);
1847
1848 return csum;
1849}
1850EXPORT_SYMBOL(skb_checksum);
1851
1852/* Both of above in one bottle. */
1853
1854__wsum skb_copy_and_csum_bits(const struct sk_buff *skb, int offset,
1855 u8 *to, int len, __wsum csum)
1856{
1857 int start = skb_headlen(skb);
1858 int i, copy = start - offset;
1859 struct sk_buff *frag_iter;
1860 int pos = 0;
1861
1862 /* Copy header. */
1863 if (copy > 0) {
1864 if (copy > len)
1865 copy = len;
1866 csum = csum_partial_copy_nocheck(skb->data + offset, to,
1867 copy, csum);
1868 if ((len -= copy) == 0)
1869 return csum;
1870 offset += copy;
1871 to += copy;
1872 pos = copy;
1873 }
1874
1875 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
1876 int end;
1877
1878 WARN_ON(start > offset + len);
1879
1880 end = start + skb_shinfo(skb)->frags[i].size;
1881 if ((copy = end - offset) > 0) {
1882 __wsum csum2;
1883 u8 *vaddr;
1884 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
1885
1886 if (copy > len)
1887 copy = len;
1888 vaddr = kmap_skb_frag(frag);
1889 csum2 = csum_partial_copy_nocheck(vaddr +
1890 frag->page_offset +
1891 offset - start, to,
1892 copy, 0);
1893 kunmap_skb_frag(vaddr);
1894 csum = csum_block_add(csum, csum2, pos);
1895 if (!(len -= copy))
1896 return csum;
1897 offset += copy;
1898 to += copy;
1899 pos += copy;
1900 }
1901 start = end;
1902 }
1903
1904 skb_walk_frags(skb, frag_iter) {
1905 __wsum csum2;
1906 int end;
1907
1908 WARN_ON(start > offset + len);
1909
1910 end = start + frag_iter->len;
1911 if ((copy = end - offset) > 0) {
1912 if (copy > len)
1913 copy = len;
1914 csum2 = skb_copy_and_csum_bits(frag_iter,
1915 offset - start,
1916 to, copy, 0);
1917 csum = csum_block_add(csum, csum2, pos);
1918 if ((len -= copy) == 0)
1919 return csum;
1920 offset += copy;
1921 to += copy;
1922 pos += copy;
1923 }
1924 start = end;
1925 }
1926 BUG_ON(len);
1927 return csum;
1928}
1929EXPORT_SYMBOL(skb_copy_and_csum_bits);
1930
1931void skb_copy_and_csum_dev(const struct sk_buff *skb, u8 *to)
1932{
1933 __wsum csum;
1934 long csstart;
1935
1936 if (skb->ip_summed == CHECKSUM_PARTIAL)
1937 csstart = skb_checksum_start_offset(skb);
1938 else
1939 csstart = skb_headlen(skb);
1940
1941 BUG_ON(csstart > skb_headlen(skb));
1942
1943 skb_copy_from_linear_data(skb, to, csstart);
1944
1945 csum = 0;
1946 if (csstart != skb->len)
1947 csum = skb_copy_and_csum_bits(skb, csstart, to + csstart,
1948 skb->len - csstart, 0);
1949
1950 if (skb->ip_summed == CHECKSUM_PARTIAL) {
1951 long csstuff = csstart + skb->csum_offset;
1952
1953 *((__sum16 *)(to + csstuff)) = csum_fold(csum);
1954 }
1955}
1956EXPORT_SYMBOL(skb_copy_and_csum_dev);
1957
1958/**
1959 * skb_dequeue - remove from the head of the queue
1960 * @list: list to dequeue from
1961 *
1962 * Remove the head of the list. The list lock is taken so the function
1963 * may be used safely with other locking list functions. The head item is
1964 * returned or %NULL if the list is empty.
1965 */
1966
1967struct sk_buff *skb_dequeue(struct sk_buff_head *list)
1968{
1969 unsigned long flags;
1970 struct sk_buff *result;
1971
1972 spin_lock_irqsave(&list->lock, flags);
1973 result = __skb_dequeue(list);
1974 spin_unlock_irqrestore(&list->lock, flags);
1975 return result;
1976}
1977EXPORT_SYMBOL(skb_dequeue);
1978
1979/**
1980 * skb_dequeue_tail - remove from the tail of the queue
1981 * @list: list to dequeue from
1982 *
1983 * Remove the tail of the list. The list lock is taken so the function
1984 * may be used safely with other locking list functions. The tail item is
1985 * returned or %NULL if the list is empty.
1986 */
1987struct sk_buff *skb_dequeue_tail(struct sk_buff_head *list)
1988{
1989 unsigned long flags;
1990 struct sk_buff *result;
1991
1992 spin_lock_irqsave(&list->lock, flags);
1993 result = __skb_dequeue_tail(list);
1994 spin_unlock_irqrestore(&list->lock, flags);
1995 return result;
1996}
1997EXPORT_SYMBOL(skb_dequeue_tail);
1998
1999/**
2000 * skb_queue_purge - empty a list
2001 * @list: list to empty
2002 *
2003 * Delete all buffers on an &sk_buff list. Each buffer is removed from
2004 * the list and one reference dropped. This function takes the list
2005 * lock and is atomic with respect to other list locking functions.
2006 */
2007void skb_queue_purge(struct sk_buff_head *list)
2008{
2009 struct sk_buff *skb;
2010 while ((skb = skb_dequeue(list)) != NULL)
2011 kfree_skb(skb);
2012}
2013EXPORT_SYMBOL(skb_queue_purge);
2014
2015/**
2016 * skb_queue_head - queue a buffer at the list head
2017 * @list: list to use
2018 * @newsk: buffer to queue
2019 *
2020 * Queue a buffer at the start of the list. This function takes the
2021 * list lock and can be used safely with other locking &sk_buff functions
2022 * safely.
2023 *
2024 * A buffer cannot be placed on two lists at the same time.
2025 */
2026void skb_queue_head(struct sk_buff_head *list, struct sk_buff *newsk)
2027{
2028 unsigned long flags;
2029
2030 spin_lock_irqsave(&list->lock, flags);
2031 __skb_queue_head(list, newsk);
2032 spin_unlock_irqrestore(&list->lock, flags);
2033}
2034EXPORT_SYMBOL(skb_queue_head);
2035
2036/**
2037 * skb_queue_tail - queue a buffer at the list tail
2038 * @list: list to use
2039 * @newsk: buffer to queue
2040 *
2041 * Queue a buffer at the tail of the list. This function takes the
2042 * list lock and can be used safely with other locking &sk_buff functions
2043 * safely.
2044 *
2045 * A buffer cannot be placed on two lists at the same time.
2046 */
2047void skb_queue_tail(struct sk_buff_head *list, struct sk_buff *newsk)
2048{
2049 unsigned long flags;
2050
2051 spin_lock_irqsave(&list->lock, flags);
2052 __skb_queue_tail(list, newsk);
2053 spin_unlock_irqrestore(&list->lock, flags);
2054}
2055EXPORT_SYMBOL(skb_queue_tail);
2056
2057/**
2058 * skb_unlink - remove a buffer from a list
2059 * @skb: buffer to remove
2060 * @list: list to use
2061 *
2062 * Remove a packet from a list. The list locks are taken and this
2063 * function is atomic with respect to other list locked calls
2064 *
2065 * You must know what list the SKB is on.
2066 */
2067void skb_unlink(struct sk_buff *skb, struct sk_buff_head *list)
2068{
2069 unsigned long flags;
2070
2071 spin_lock_irqsave(&list->lock, flags);
2072 __skb_unlink(skb, list);
2073 spin_unlock_irqrestore(&list->lock, flags);
2074}
2075EXPORT_SYMBOL(skb_unlink);
2076
2077/**
2078 * skb_append - append a buffer
2079 * @old: buffer to insert after
2080 * @newsk: buffer to insert
2081 * @list: list to use
2082 *
2083 * Place a packet after a given packet in a list. The list locks are taken
2084 * and this function is atomic with respect to other list locked calls.
2085 * A buffer cannot be placed on two lists at the same time.
2086 */
2087void skb_append(struct sk_buff *old, struct sk_buff *newsk, struct sk_buff_head *list)
2088{
2089 unsigned long flags;
2090
2091 spin_lock_irqsave(&list->lock, flags);
2092 __skb_queue_after(list, old, newsk);
2093 spin_unlock_irqrestore(&list->lock, flags);
2094}
2095EXPORT_SYMBOL(skb_append);
2096
2097/**
2098 * skb_insert - insert a buffer
2099 * @old: buffer to insert before
2100 * @newsk: buffer to insert
2101 * @list: list to use
2102 *
2103 * Place a packet before a given packet in a list. The list locks are
2104 * taken and this function is atomic with respect to other list locked
2105 * calls.
2106 *
2107 * A buffer cannot be placed on two lists at the same time.
2108 */
2109void skb_insert(struct sk_buff *old, struct sk_buff *newsk, struct sk_buff_head *list)
2110{
2111 unsigned long flags;
2112
2113 spin_lock_irqsave(&list->lock, flags);
2114 __skb_insert(newsk, old->prev, old, list);
2115 spin_unlock_irqrestore(&list->lock, flags);
2116}
2117EXPORT_SYMBOL(skb_insert);
2118
2119static inline void skb_split_inside_header(struct sk_buff *skb,
2120 struct sk_buff* skb1,
2121 const u32 len, const int pos)
2122{
2123 int i;
2124
2125 skb_copy_from_linear_data_offset(skb, len, skb_put(skb1, pos - len),
2126 pos - len);
2127 /* And move data appendix as is. */
2128 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
2129 skb_shinfo(skb1)->frags[i] = skb_shinfo(skb)->frags[i];
2130
2131 skb_shinfo(skb1)->nr_frags = skb_shinfo(skb)->nr_frags;
2132 skb_shinfo(skb)->nr_frags = 0;
2133 skb1->data_len = skb->data_len;
2134 skb1->len += skb1->data_len;
2135 skb->data_len = 0;
2136 skb->len = len;
2137 skb_set_tail_pointer(skb, len);
2138}
2139
2140static inline void skb_split_no_header(struct sk_buff *skb,
2141 struct sk_buff* skb1,
2142 const u32 len, int pos)
2143{
2144 int i, k = 0;
2145 const int nfrags = skb_shinfo(skb)->nr_frags;
2146
2147 skb_shinfo(skb)->nr_frags = 0;
2148 skb1->len = skb1->data_len = skb->len - len;
2149 skb->len = len;
2150 skb->data_len = len - pos;
2151
2152 for (i = 0; i < nfrags; i++) {
2153 int size = skb_shinfo(skb)->frags[i].size;
2154
2155 if (pos + size > len) {
2156 skb_shinfo(skb1)->frags[k] = skb_shinfo(skb)->frags[i];
2157
2158 if (pos < len) {
2159 /* Split frag.
2160 * We have two variants in this case:
2161 * 1. Move all the frag to the second
2162 * part, if it is possible. F.e.
2163 * this approach is mandatory for TUX,
2164 * where splitting is expensive.
2165 * 2. Split is accurately. We make this.
2166 */
2167 get_page(skb_shinfo(skb)->frags[i].page);
2168 skb_shinfo(skb1)->frags[0].page_offset += len - pos;
2169 skb_shinfo(skb1)->frags[0].size -= len - pos;
2170 skb_shinfo(skb)->frags[i].size = len - pos;
2171 skb_shinfo(skb)->nr_frags++;
2172 }
2173 k++;
2174 } else
2175 skb_shinfo(skb)->nr_frags++;
2176 pos += size;
2177 }
2178 skb_shinfo(skb1)->nr_frags = k;
2179}
2180
2181/**
2182 * skb_split - Split fragmented skb to two parts at length len.
2183 * @skb: the buffer to split
2184 * @skb1: the buffer to receive the second part
2185 * @len: new length for skb
2186 */
2187void skb_split(struct sk_buff *skb, struct sk_buff *skb1, const u32 len)
2188{
2189 int pos = skb_headlen(skb);
2190
2191 if (len < pos) /* Split line is inside header. */
2192 skb_split_inside_header(skb, skb1, len, pos);
2193 else /* Second chunk has no header, nothing to copy. */
2194 skb_split_no_header(skb, skb1, len, pos);
2195}
2196EXPORT_SYMBOL(skb_split);
2197
2198/* Shifting from/to a cloned skb is a no-go.
2199 *
2200 * Caller cannot keep skb_shinfo related pointers past calling here!
2201 */
2202static int skb_prepare_for_shift(struct sk_buff *skb)
2203{
2204 return skb_cloned(skb) && pskb_expand_head(skb, 0, 0, GFP_ATOMIC);
2205}
2206
2207/**
2208 * skb_shift - Shifts paged data partially from skb to another
2209 * @tgt: buffer into which tail data gets added
2210 * @skb: buffer from which the paged data comes from
2211 * @shiftlen: shift up to this many bytes
2212 *
2213 * Attempts to shift up to shiftlen worth of bytes, which may be less than
2214 * the length of the skb, from tgt to skb. Returns number bytes shifted.
2215 * It's up to caller to free skb if everything was shifted.
2216 *
2217 * If @tgt runs out of frags, the whole operation is aborted.
2218 *
2219 * Skb cannot include anything else but paged data while tgt is allowed
2220 * to have non-paged data as well.
2221 *
2222 * TODO: full sized shift could be optimized but that would need
2223 * specialized skb free'er to handle frags without up-to-date nr_frags.
2224 */
2225int skb_shift(struct sk_buff *tgt, struct sk_buff *skb, int shiftlen)
2226{
2227 int from, to, merge, todo;
2228 struct skb_frag_struct *fragfrom, *fragto;
2229
2230 BUG_ON(shiftlen > skb->len);
2231 BUG_ON(skb_headlen(skb)); /* Would corrupt stream */
2232
2233 todo = shiftlen;
2234 from = 0;
2235 to = skb_shinfo(tgt)->nr_frags;
2236 fragfrom = &skb_shinfo(skb)->frags[from];
2237
2238 /* Actual merge is delayed until the point when we know we can
2239 * commit all, so that we don't have to undo partial changes
2240 */
2241 if (!to ||
2242 !skb_can_coalesce(tgt, to, fragfrom->page, fragfrom->page_offset)) {
2243 merge = -1;
2244 } else {
2245 merge = to - 1;
2246
2247 todo -= fragfrom->size;
2248 if (todo < 0) {
2249 if (skb_prepare_for_shift(skb) ||
2250 skb_prepare_for_shift(tgt))
2251 return 0;
2252
2253 /* All previous frag pointers might be stale! */
2254 fragfrom = &skb_shinfo(skb)->frags[from];
2255 fragto = &skb_shinfo(tgt)->frags[merge];
2256
2257 fragto->size += shiftlen;
2258 fragfrom->size -= shiftlen;
2259 fragfrom->page_offset += shiftlen;
2260
2261 goto onlymerged;
2262 }
2263
2264 from++;
2265 }
2266
2267 /* Skip full, not-fitting skb to avoid expensive operations */
2268 if ((shiftlen == skb->len) &&
2269 (skb_shinfo(skb)->nr_frags - from) > (MAX_SKB_FRAGS - to))
2270 return 0;
2271
2272 if (skb_prepare_for_shift(skb) || skb_prepare_for_shift(tgt))
2273 return 0;
2274
2275 while ((todo > 0) && (from < skb_shinfo(skb)->nr_frags)) {
2276 if (to == MAX_SKB_FRAGS)
2277 return 0;
2278
2279 fragfrom = &skb_shinfo(skb)->frags[from];
2280 fragto = &skb_shinfo(tgt)->frags[to];
2281
2282 if (todo >= fragfrom->size) {
2283 *fragto = *fragfrom;
2284 todo -= fragfrom->size;
2285 from++;
2286 to++;
2287
2288 } else {
2289 get_page(fragfrom->page);
2290 fragto->page = fragfrom->page;
2291 fragto->page_offset = fragfrom->page_offset;
2292 fragto->size = todo;
2293
2294 fragfrom->page_offset += todo;
2295 fragfrom->size -= todo;
2296 todo = 0;
2297
2298 to++;
2299 break;
2300 }
2301 }
2302
2303 /* Ready to "commit" this state change to tgt */
2304 skb_shinfo(tgt)->nr_frags = to;
2305
2306 if (merge >= 0) {
2307 fragfrom = &skb_shinfo(skb)->frags[0];
2308 fragto = &skb_shinfo(tgt)->frags[merge];
2309
2310 fragto->size += fragfrom->size;
2311 put_page(fragfrom->page);
2312 }
2313
2314 /* Reposition in the original skb */
2315 to = 0;
2316 while (from < skb_shinfo(skb)->nr_frags)
2317 skb_shinfo(skb)->frags[to++] = skb_shinfo(skb)->frags[from++];
2318 skb_shinfo(skb)->nr_frags = to;
2319
2320 BUG_ON(todo > 0 && !skb_shinfo(skb)->nr_frags);
2321
2322onlymerged:
2323 /* Most likely the tgt won't ever need its checksum anymore, skb on
2324 * the other hand might need it if it needs to be resent
2325 */
2326 tgt->ip_summed = CHECKSUM_PARTIAL;
2327 skb->ip_summed = CHECKSUM_PARTIAL;
2328
2329 /* Yak, is it really working this way? Some helper please? */
2330 skb->len -= shiftlen;
2331 skb->data_len -= shiftlen;
2332 skb->truesize -= shiftlen;
2333 tgt->len += shiftlen;
2334 tgt->data_len += shiftlen;
2335 tgt->truesize += shiftlen;
2336
2337 return shiftlen;
2338}
2339
2340/**
2341 * skb_prepare_seq_read - Prepare a sequential read of skb data
2342 * @skb: the buffer to read
2343 * @from: lower offset of data to be read
2344 * @to: upper offset of data to be read
2345 * @st: state variable
2346 *
2347 * Initializes the specified state variable. Must be called before
2348 * invoking skb_seq_read() for the first time.
2349 */
2350void skb_prepare_seq_read(struct sk_buff *skb, unsigned int from,
2351 unsigned int to, struct skb_seq_state *st)
2352{
2353 st->lower_offset = from;
2354 st->upper_offset = to;
2355 st->root_skb = st->cur_skb = skb;
2356 st->frag_idx = st->stepped_offset = 0;
2357 st->frag_data = NULL;
2358}
2359EXPORT_SYMBOL(skb_prepare_seq_read);
2360
2361/**
2362 * skb_seq_read - Sequentially read skb data
2363 * @consumed: number of bytes consumed by the caller so far
2364 * @data: destination pointer for data to be returned
2365 * @st: state variable
2366 *
2367 * Reads a block of skb data at &consumed relative to the
2368 * lower offset specified to skb_prepare_seq_read(). Assigns
2369 * the head of the data block to &data and returns the length
2370 * of the block or 0 if the end of the skb data or the upper
2371 * offset has been reached.
2372 *
2373 * The caller is not required to consume all of the data
2374 * returned, i.e. &consumed is typically set to the number
2375 * of bytes already consumed and the next call to
2376 * skb_seq_read() will return the remaining part of the block.
2377 *
2378 * Note 1: The size of each block of data returned can be arbitrary,
2379 * this limitation is the cost for zerocopy seqeuental
2380 * reads of potentially non linear data.
2381 *
2382 * Note 2: Fragment lists within fragments are not implemented
2383 * at the moment, state->root_skb could be replaced with
2384 * a stack for this purpose.
2385 */
2386unsigned int skb_seq_read(unsigned int consumed, const u8 **data,
2387 struct skb_seq_state *st)
2388{
2389 unsigned int block_limit, abs_offset = consumed + st->lower_offset;
2390 skb_frag_t *frag;
2391
2392 if (unlikely(abs_offset >= st->upper_offset))
2393 return 0;
2394
2395next_skb:
2396 block_limit = skb_headlen(st->cur_skb) + st->stepped_offset;
2397
2398 if (abs_offset < block_limit && !st->frag_data) {
2399 *data = st->cur_skb->data + (abs_offset - st->stepped_offset);
2400 return block_limit - abs_offset;
2401 }
2402
2403 if (st->frag_idx == 0 && !st->frag_data)
2404 st->stepped_offset += skb_headlen(st->cur_skb);
2405
2406 while (st->frag_idx < skb_shinfo(st->cur_skb)->nr_frags) {
2407 frag = &skb_shinfo(st->cur_skb)->frags[st->frag_idx];
2408 block_limit = frag->size + st->stepped_offset;
2409
2410 if (abs_offset < block_limit) {
2411 if (!st->frag_data)
2412 st->frag_data = kmap_skb_frag(frag);
2413
2414 *data = (u8 *) st->frag_data + frag->page_offset +
2415 (abs_offset - st->stepped_offset);
2416
2417 return block_limit - abs_offset;
2418 }
2419
2420 if (st->frag_data) {
2421 kunmap_skb_frag(st->frag_data);
2422 st->frag_data = NULL;
2423 }
2424
2425 st->frag_idx++;
2426 st->stepped_offset += frag->size;
2427 }
2428
2429 if (st->frag_data) {
2430 kunmap_skb_frag(st->frag_data);
2431 st->frag_data = NULL;
2432 }
2433
2434 if (st->root_skb == st->cur_skb && skb_has_frag_list(st->root_skb)) {
2435 st->cur_skb = skb_shinfo(st->root_skb)->frag_list;
2436 st->frag_idx = 0;
2437 goto next_skb;
2438 } else if (st->cur_skb->next) {
2439 st->cur_skb = st->cur_skb->next;
2440 st->frag_idx = 0;
2441 goto next_skb;
2442 }
2443
2444 return 0;
2445}
2446EXPORT_SYMBOL(skb_seq_read);
2447
2448/**
2449 * skb_abort_seq_read - Abort a sequential read of skb data
2450 * @st: state variable
2451 *
2452 * Must be called if skb_seq_read() was not called until it
2453 * returned 0.
2454 */
2455void skb_abort_seq_read(struct skb_seq_state *st)
2456{
2457 if (st->frag_data)
2458 kunmap_skb_frag(st->frag_data);
2459}
2460EXPORT_SYMBOL(skb_abort_seq_read);
2461
2462#define TS_SKB_CB(state) ((struct skb_seq_state *) &((state)->cb))
2463
2464static unsigned int skb_ts_get_next_block(unsigned int offset, const u8 **text,
2465 struct ts_config *conf,
2466 struct ts_state *state)
2467{
2468 return skb_seq_read(offset, text, TS_SKB_CB(state));
2469}
2470
2471static void skb_ts_finish(struct ts_config *conf, struct ts_state *state)
2472{
2473 skb_abort_seq_read(TS_SKB_CB(state));
2474}
2475
2476/**
2477 * skb_find_text - Find a text pattern in skb data
2478 * @skb: the buffer to look in
2479 * @from: search offset
2480 * @to: search limit
2481 * @config: textsearch configuration
2482 * @state: uninitialized textsearch state variable
2483 *
2484 * Finds a pattern in the skb data according to the specified
2485 * textsearch configuration. Use textsearch_next() to retrieve
2486 * subsequent occurrences of the pattern. Returns the offset
2487 * to the first occurrence or UINT_MAX if no match was found.
2488 */
2489unsigned int skb_find_text(struct sk_buff *skb, unsigned int from,
2490 unsigned int to, struct ts_config *config,
2491 struct ts_state *state)
2492{
2493 unsigned int ret;
2494
2495 config->get_next_block = skb_ts_get_next_block;
2496 config->finish = skb_ts_finish;
2497
2498 skb_prepare_seq_read(skb, from, to, TS_SKB_CB(state));
2499
2500 ret = textsearch_find(config, state);
2501 return (ret <= to - from ? ret : UINT_MAX);
2502}
2503EXPORT_SYMBOL(skb_find_text);
2504
2505/**
2506 * skb_append_datato_frags: - append the user data to a skb
2507 * @sk: sock structure
2508 * @skb: skb structure to be appened with user data.
2509 * @getfrag: call back function to be used for getting the user data
2510 * @from: pointer to user message iov
2511 * @length: length of the iov message
2512 *
2513 * Description: This procedure append the user data in the fragment part
2514 * of the skb if any page alloc fails user this procedure returns -ENOMEM
2515 */
2516int skb_append_datato_frags(struct sock *sk, struct sk_buff *skb,
2517 int (*getfrag)(void *from, char *to, int offset,
2518 int len, int odd, struct sk_buff *skb),
2519 void *from, int length)
2520{
2521 int frg_cnt = 0;
2522 skb_frag_t *frag = NULL;
2523 struct page *page = NULL;
2524 int copy, left;
2525 int offset = 0;
2526 int ret;
2527
2528 do {
2529 /* Return error if we don't have space for new frag */
2530 frg_cnt = skb_shinfo(skb)->nr_frags;
2531 if (frg_cnt >= MAX_SKB_FRAGS)
2532 return -EFAULT;
2533
2534 /* allocate a new page for next frag */
2535 page = alloc_pages(sk->sk_allocation, 0);
2536
2537 /* If alloc_page fails just return failure and caller will
2538 * free previous allocated pages by doing kfree_skb()
2539 */
2540 if (page == NULL)
2541 return -ENOMEM;
2542
2543 /* initialize the next frag */
2544 skb_fill_page_desc(skb, frg_cnt, page, 0, 0);
2545 skb->truesize += PAGE_SIZE;
2546 atomic_add(PAGE_SIZE, &sk->sk_wmem_alloc);
2547
2548 /* get the new initialized frag */
2549 frg_cnt = skb_shinfo(skb)->nr_frags;
2550 frag = &skb_shinfo(skb)->frags[frg_cnt - 1];
2551
2552 /* copy the user data to page */
2553 left = PAGE_SIZE - frag->page_offset;
2554 copy = (length > left)? left : length;
2555
2556 ret = getfrag(from, (page_address(frag->page) +
2557 frag->page_offset + frag->size),
2558 offset, copy, 0, skb);
2559 if (ret < 0)
2560 return -EFAULT;
2561
2562 /* copy was successful so update the size parameters */
2563 frag->size += copy;
2564 skb->len += copy;
2565 skb->data_len += copy;
2566 offset += copy;
2567 length -= copy;
2568
2569 } while (length > 0);
2570
2571 return 0;
2572}
2573EXPORT_SYMBOL(skb_append_datato_frags);
2574
2575/**
2576 * skb_pull_rcsum - pull skb and update receive checksum
2577 * @skb: buffer to update
2578 * @len: length of data pulled
2579 *
2580 * This function performs an skb_pull on the packet and updates
2581 * the CHECKSUM_COMPLETE checksum. It should be used on
2582 * receive path processing instead of skb_pull unless you know
2583 * that the checksum difference is zero (e.g., a valid IP header)
2584 * or you are setting ip_summed to CHECKSUM_NONE.
2585 */
2586unsigned char *skb_pull_rcsum(struct sk_buff *skb, unsigned int len)
2587{
2588 BUG_ON(len > skb->len);
2589 skb->len -= len;
2590 BUG_ON(skb->len < skb->data_len);
2591 skb_postpull_rcsum(skb, skb->data, len);
2592 return skb->data += len;
2593}
2594EXPORT_SYMBOL_GPL(skb_pull_rcsum);
2595
2596/**
2597 * skb_segment - Perform protocol segmentation on skb.
2598 * @skb: buffer to segment
2599 * @features: features for the output path (see dev->features)
2600 *
2601 * This function performs segmentation on the given skb. It returns
2602 * a pointer to the first in a list of new skbs for the segments.
2603 * In case of error it returns ERR_PTR(err).
2604 */
2605struct sk_buff *skb_segment(struct sk_buff *skb, u32 features)
2606{
2607 struct sk_buff *segs = NULL;
2608 struct sk_buff *tail = NULL;
2609 struct sk_buff *fskb = skb_shinfo(skb)->frag_list;
2610 unsigned int mss = skb_shinfo(skb)->gso_size;
2611 unsigned int doffset = skb->data - skb_mac_header(skb);
2612 unsigned int offset = doffset;
2613 unsigned int headroom;
2614 unsigned int len;
2615 int sg = !!(features & NETIF_F_SG);
2616 int nfrags = skb_shinfo(skb)->nr_frags;
2617 int err = -ENOMEM;
2618 int i = 0;
2619 int pos;
2620
2621 __skb_push(skb, doffset);
2622 headroom = skb_headroom(skb);
2623 pos = skb_headlen(skb);
2624
2625 do {
2626 struct sk_buff *nskb;
2627 skb_frag_t *frag;
2628 int hsize;
2629 int size;
2630
2631 len = skb->len - offset;
2632 if (len > mss)
2633 len = mss;
2634
2635 hsize = skb_headlen(skb) - offset;
2636 if (hsize < 0)
2637 hsize = 0;
2638 if (hsize > len || !sg)
2639 hsize = len;
2640
2641 if (!hsize && i >= nfrags) {
2642 BUG_ON(fskb->len != len);
2643
2644 pos += len;
2645 nskb = skb_clone(fskb, GFP_ATOMIC);
2646 fskb = fskb->next;
2647
2648 if (unlikely(!nskb))
2649 goto err;
2650
2651 hsize = skb_end_pointer(nskb) - nskb->head;
2652 if (skb_cow_head(nskb, doffset + headroom)) {
2653 kfree_skb(nskb);
2654 goto err;
2655 }
2656
2657 nskb->truesize += skb_end_pointer(nskb) - nskb->head -
2658 hsize;
2659 skb_release_head_state(nskb);
2660 __skb_push(nskb, doffset);
2661 } else {
2662 nskb = alloc_skb(hsize + doffset + headroom,
2663 GFP_ATOMIC);
2664
2665 if (unlikely(!nskb))
2666 goto err;
2667
2668 skb_reserve(nskb, headroom);
2669 __skb_put(nskb, doffset);
2670 }
2671
2672 if (segs)
2673 tail->next = nskb;
2674 else
2675 segs = nskb;
2676 tail = nskb;
2677
2678 __copy_skb_header(nskb, skb);
2679 nskb->mac_len = skb->mac_len;
2680
2681 /* nskb and skb might have different headroom */
2682 if (nskb->ip_summed == CHECKSUM_PARTIAL)
2683 nskb->csum_start += skb_headroom(nskb) - headroom;
2684
2685 skb_reset_mac_header(nskb);
2686 skb_set_network_header(nskb, skb->mac_len);
2687 nskb->transport_header = (nskb->network_header +
2688 skb_network_header_len(skb));
2689 skb_copy_from_linear_data(skb, nskb->data, doffset);
2690
2691 if (fskb != skb_shinfo(skb)->frag_list)
2692 continue;
2693
2694 if (!sg) {
2695 nskb->ip_summed = CHECKSUM_NONE;
2696 nskb->csum = skb_copy_and_csum_bits(skb, offset,
2697 skb_put(nskb, len),
2698 len, 0);
2699 continue;
2700 }
2701
2702 frag = skb_shinfo(nskb)->frags;
2703
2704 skb_copy_from_linear_data_offset(skb, offset,
2705 skb_put(nskb, hsize), hsize);
2706
2707 while (pos < offset + len && i < nfrags) {
2708 *frag = skb_shinfo(skb)->frags[i];
2709 get_page(frag->page);
2710 size = frag->size;
2711
2712 if (pos < offset) {
2713 frag->page_offset += offset - pos;
2714 frag->size -= offset - pos;
2715 }
2716
2717 skb_shinfo(nskb)->nr_frags++;
2718
2719 if (pos + size <= offset + len) {
2720 i++;
2721 pos += size;
2722 } else {
2723 frag->size -= pos + size - (offset + len);
2724 goto skip_fraglist;
2725 }
2726
2727 frag++;
2728 }
2729
2730 if (pos < offset + len) {
2731 struct sk_buff *fskb2 = fskb;
2732
2733 BUG_ON(pos + fskb->len != offset + len);
2734
2735 pos += fskb->len;
2736 fskb = fskb->next;
2737
2738 if (fskb2->next) {
2739 fskb2 = skb_clone(fskb2, GFP_ATOMIC);
2740 if (!fskb2)
2741 goto err;
2742 } else
2743 skb_get(fskb2);
2744
2745 SKB_FRAG_ASSERT(nskb);
2746 skb_shinfo(nskb)->frag_list = fskb2;
2747 }
2748
2749skip_fraglist:
2750 nskb->data_len = len - hsize;
2751 nskb->len += nskb->data_len;
2752 nskb->truesize += nskb->data_len;
2753 } while ((offset += len) < skb->len);
2754
2755 return segs;
2756
2757err:
2758 while ((skb = segs)) {
2759 segs = skb->next;
2760 kfree_skb(skb);
2761 }
2762 return ERR_PTR(err);
2763}
2764EXPORT_SYMBOL_GPL(skb_segment);
2765
2766int skb_gro_receive(struct sk_buff **head, struct sk_buff *skb)
2767{
2768 struct sk_buff *p = *head;
2769 struct sk_buff *nskb;
2770 struct skb_shared_info *skbinfo = skb_shinfo(skb);
2771 struct skb_shared_info *pinfo = skb_shinfo(p);
2772 unsigned int headroom;
2773 unsigned int len = skb_gro_len(skb);
2774 unsigned int offset = skb_gro_offset(skb);
2775 unsigned int headlen = skb_headlen(skb);
2776
2777 if (p->len + len >= 65536)
2778 return -E2BIG;
2779
2780 if (pinfo->frag_list)
2781 goto merge;
2782 else if (headlen <= offset) {
2783 skb_frag_t *frag;
2784 skb_frag_t *frag2;
2785 int i = skbinfo->nr_frags;
2786 int nr_frags = pinfo->nr_frags + i;
2787
2788 offset -= headlen;
2789
2790 if (nr_frags > MAX_SKB_FRAGS)
2791 return -E2BIG;
2792
2793 pinfo->nr_frags = nr_frags;
2794 skbinfo->nr_frags = 0;
2795
2796 frag = pinfo->frags + nr_frags;
2797 frag2 = skbinfo->frags + i;
2798 do {
2799 *--frag = *--frag2;
2800 } while (--i);
2801
2802 frag->page_offset += offset;
2803 frag->size -= offset;
2804
2805 skb->truesize -= skb->data_len;
2806 skb->len -= skb->data_len;
2807 skb->data_len = 0;
2808
2809 NAPI_GRO_CB(skb)->free = 1;
2810 goto done;
2811 } else if (skb_gro_len(p) != pinfo->gso_size)
2812 return -E2BIG;
2813
2814 headroom = skb_headroom(p);
2815 nskb = alloc_skb(headroom + skb_gro_offset(p), GFP_ATOMIC);
2816 if (unlikely(!nskb))
2817 return -ENOMEM;
2818
2819 __copy_skb_header(nskb, p);
2820 nskb->mac_len = p->mac_len;
2821
2822 skb_reserve(nskb, headroom);
2823 __skb_put(nskb, skb_gro_offset(p));
2824
2825 skb_set_mac_header(nskb, skb_mac_header(p) - p->data);
2826 skb_set_network_header(nskb, skb_network_offset(p));
2827 skb_set_transport_header(nskb, skb_transport_offset(p));
2828
2829 __skb_pull(p, skb_gro_offset(p));
2830 memcpy(skb_mac_header(nskb), skb_mac_header(p),
2831 p->data - skb_mac_header(p));
2832
2833 *NAPI_GRO_CB(nskb) = *NAPI_GRO_CB(p);
2834 skb_shinfo(nskb)->frag_list = p;
2835 skb_shinfo(nskb)->gso_size = pinfo->gso_size;
2836 pinfo->gso_size = 0;
2837 skb_header_release(p);
2838 nskb->prev = p;
2839
2840 nskb->data_len += p->len;
2841 nskb->truesize += p->len;
2842 nskb->len += p->len;
2843
2844 *head = nskb;
2845 nskb->next = p->next;
2846 p->next = NULL;
2847
2848 p = nskb;
2849
2850merge:
2851 if (offset > headlen) {
2852 unsigned int eat = offset - headlen;
2853
2854 skbinfo->frags[0].page_offset += eat;
2855 skbinfo->frags[0].size -= eat;
2856 skb->data_len -= eat;
2857 skb->len -= eat;
2858 offset = headlen;
2859 }
2860
2861 __skb_pull(skb, offset);
2862
2863 p->prev->next = skb;
2864 p->prev = skb;
2865 skb_header_release(skb);
2866
2867done:
2868 NAPI_GRO_CB(p)->count++;
2869 p->data_len += len;
2870 p->truesize += len;
2871 p->len += len;
2872
2873 NAPI_GRO_CB(skb)->same_flow = 1;
2874 return 0;
2875}
2876EXPORT_SYMBOL_GPL(skb_gro_receive);
2877
2878void __init skb_init(void)
2879{
2880 skbuff_head_cache = kmem_cache_create("skbuff_head_cache",
2881 sizeof(struct sk_buff),
2882 0,
2883 SLAB_HWCACHE_ALIGN|SLAB_PANIC,
2884 NULL);
2885 skbuff_fclone_cache = kmem_cache_create("skbuff_fclone_cache",
2886 (2*sizeof(struct sk_buff)) +
2887 sizeof(atomic_t),
2888 0,
2889 SLAB_HWCACHE_ALIGN|SLAB_PANIC,
2890 NULL);
2891}
2892
2893/**
2894 * skb_to_sgvec - Fill a scatter-gather list from a socket buffer
2895 * @skb: Socket buffer containing the buffers to be mapped
2896 * @sg: The scatter-gather list to map into
2897 * @offset: The offset into the buffer's contents to start mapping
2898 * @len: Length of buffer space to be mapped
2899 *
2900 * Fill the specified scatter-gather list with mappings/pointers into a
2901 * region of the buffer space attached to a socket buffer.
2902 */
2903static int
2904__skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int len)
2905{
2906 int start = skb_headlen(skb);
2907 int i, copy = start - offset;
2908 struct sk_buff *frag_iter;
2909 int elt = 0;
2910
2911 if (copy > 0) {
2912 if (copy > len)
2913 copy = len;
2914 sg_set_buf(sg, skb->data + offset, copy);
2915 elt++;
2916 if ((len -= copy) == 0)
2917 return elt;
2918 offset += copy;
2919 }
2920
2921 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
2922 int end;
2923
2924 WARN_ON(start > offset + len);
2925
2926 end = start + skb_shinfo(skb)->frags[i].size;
2927 if ((copy = end - offset) > 0) {
2928 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
2929
2930 if (copy > len)
2931 copy = len;
2932 sg_set_page(&sg[elt], frag->page, copy,
2933 frag->page_offset+offset-start);
2934 elt++;
2935 if (!(len -= copy))
2936 return elt;
2937 offset += copy;
2938 }
2939 start = end;
2940 }
2941
2942 skb_walk_frags(skb, frag_iter) {
2943 int end;
2944
2945 WARN_ON(start > offset + len);
2946
2947 end = start + frag_iter->len;
2948 if ((copy = end - offset) > 0) {
2949 if (copy > len)
2950 copy = len;
2951 elt += __skb_to_sgvec(frag_iter, sg+elt, offset - start,
2952 copy);
2953 if ((len -= copy) == 0)
2954 return elt;
2955 offset += copy;
2956 }
2957 start = end;
2958 }
2959 BUG_ON(len);
2960 return elt;
2961}
2962
2963int skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int len)
2964{
2965 int nsg = __skb_to_sgvec(skb, sg, offset, len);
2966
2967 sg_mark_end(&sg[nsg - 1]);
2968
2969 return nsg;
2970}
2971EXPORT_SYMBOL_GPL(skb_to_sgvec);
2972
2973/**
2974 * skb_cow_data - Check that a socket buffer's data buffers are writable
2975 * @skb: The socket buffer to check.
2976 * @tailbits: Amount of trailing space to be added
2977 * @trailer: Returned pointer to the skb where the @tailbits space begins
2978 *
2979 * Make sure that the data buffers attached to a socket buffer are
2980 * writable. If they are not, private copies are made of the data buffers
2981 * and the socket buffer is set to use these instead.
2982 *
2983 * If @tailbits is given, make sure that there is space to write @tailbits
2984 * bytes of data beyond current end of socket buffer. @trailer will be
2985 * set to point to the skb in which this space begins.
2986 *
2987 * The number of scatterlist elements required to completely map the
2988 * COW'd and extended socket buffer will be returned.
2989 */
2990int skb_cow_data(struct sk_buff *skb, int tailbits, struct sk_buff **trailer)
2991{
2992 int copyflag;
2993 int elt;
2994 struct sk_buff *skb1, **skb_p;
2995
2996 /* If skb is cloned or its head is paged, reallocate
2997 * head pulling out all the pages (pages are considered not writable
2998 * at the moment even if they are anonymous).
2999 */
3000 if ((skb_cloned(skb) || skb_shinfo(skb)->nr_frags) &&
3001 __pskb_pull_tail(skb, skb_pagelen(skb)-skb_headlen(skb)) == NULL)
3002 return -ENOMEM;
3003
3004 /* Easy case. Most of packets will go this way. */
3005 if (!skb_has_frag_list(skb)) {
3006 /* A little of trouble, not enough of space for trailer.
3007 * This should not happen, when stack is tuned to generate
3008 * good frames. OK, on miss we reallocate and reserve even more
3009 * space, 128 bytes is fair. */
3010
3011 if (skb_tailroom(skb) < tailbits &&
3012 pskb_expand_head(skb, 0, tailbits-skb_tailroom(skb)+128, GFP_ATOMIC))
3013 return -ENOMEM;
3014
3015 /* Voila! */
3016 *trailer = skb;
3017 return 1;
3018 }
3019
3020 /* Misery. We are in troubles, going to mincer fragments... */
3021
3022 elt = 1;
3023 skb_p = &skb_shinfo(skb)->frag_list;
3024 copyflag = 0;
3025
3026 while ((skb1 = *skb_p) != NULL) {
3027 int ntail = 0;
3028
3029 /* The fragment is partially pulled by someone,
3030 * this can happen on input. Copy it and everything
3031 * after it. */
3032
3033 if (skb_shared(skb1))
3034 copyflag = 1;
3035
3036 /* If the skb is the last, worry about trailer. */
3037
3038 if (skb1->next == NULL && tailbits) {
3039 if (skb_shinfo(skb1)->nr_frags ||
3040 skb_has_frag_list(skb1) ||
3041 skb_tailroom(skb1) < tailbits)
3042 ntail = tailbits + 128;
3043 }
3044
3045 if (copyflag ||
3046 skb_cloned(skb1) ||
3047 ntail ||
3048 skb_shinfo(skb1)->nr_frags ||
3049 skb_has_frag_list(skb1)) {
3050 struct sk_buff *skb2;
3051
3052 /* Fuck, we are miserable poor guys... */
3053 if (ntail == 0)
3054 skb2 = skb_copy(skb1, GFP_ATOMIC);
3055 else
3056 skb2 = skb_copy_expand(skb1,
3057 skb_headroom(skb1),
3058 ntail,
3059 GFP_ATOMIC);
3060 if (unlikely(skb2 == NULL))
3061 return -ENOMEM;
3062
3063 if (skb1->sk)
3064 skb_set_owner_w(skb2, skb1->sk);
3065
3066 /* Looking around. Are we still alive?
3067 * OK, link new skb, drop old one */
3068
3069 skb2->next = skb1->next;
3070 *skb_p = skb2;
3071 kfree_skb(skb1);
3072 skb1 = skb2;
3073 }
3074 elt++;
3075 *trailer = skb1;
3076 skb_p = &skb1->next;
3077 }
3078
3079 return elt;
3080}
3081EXPORT_SYMBOL_GPL(skb_cow_data);
3082
3083static void sock_rmem_free(struct sk_buff *skb)
3084{
3085 struct sock *sk = skb->sk;
3086
3087 atomic_sub(skb->truesize, &sk->sk_rmem_alloc);
3088}
3089
3090/*
3091 * Note: We dont mem charge error packets (no sk_forward_alloc changes)
3092 */
3093int sock_queue_err_skb(struct sock *sk, struct sk_buff *skb)
3094{
3095 if (atomic_read(&sk->sk_rmem_alloc) + skb->truesize >=
3096 (unsigned)sk->sk_rcvbuf)
3097 return -ENOMEM;
3098
3099 skb_orphan(skb);
3100 skb->sk = sk;
3101 skb->destructor = sock_rmem_free;
3102 atomic_add(skb->truesize, &sk->sk_rmem_alloc);
3103
3104 /* before exiting rcu section, make sure dst is refcounted */
3105 skb_dst_force(skb);
3106
3107 skb_queue_tail(&sk->sk_error_queue, skb);
3108 if (!sock_flag(sk, SOCK_DEAD))
3109 sk->sk_data_ready(sk, skb->len);
3110 return 0;
3111}
3112EXPORT_SYMBOL(sock_queue_err_skb);
3113
3114void skb_tstamp_tx(struct sk_buff *orig_skb,
3115 struct skb_shared_hwtstamps *hwtstamps)
3116{
3117 struct sock *sk = orig_skb->sk;
3118 struct sock_exterr_skb *serr;
3119 struct sk_buff *skb;
3120 int err;
3121
3122 if (!sk)
3123 return;
3124
3125 skb = skb_clone(orig_skb, GFP_ATOMIC);
3126 if (!skb)
3127 return;
3128
3129 if (hwtstamps) {
3130 *skb_hwtstamps(skb) =
3131 *hwtstamps;
3132 } else {
3133 /*
3134 * no hardware time stamps available,
3135 * so keep the shared tx_flags and only
3136 * store software time stamp
3137 */
3138 skb->tstamp = ktime_get_real();
3139 }
3140
3141 serr = SKB_EXT_ERR(skb);
3142 memset(serr, 0, sizeof(*serr));
3143 serr->ee.ee_errno = ENOMSG;
3144 serr->ee.ee_origin = SO_EE_ORIGIN_TIMESTAMPING;
3145
3146 err = sock_queue_err_skb(sk, skb);
3147
3148 if (err)
3149 kfree_skb(skb);
3150}
3151EXPORT_SYMBOL_GPL(skb_tstamp_tx);
3152
3153
3154/**
3155 * skb_partial_csum_set - set up and verify partial csum values for packet
3156 * @skb: the skb to set
3157 * @start: the number of bytes after skb->data to start checksumming.
3158 * @off: the offset from start to place the checksum.
3159 *
3160 * For untrusted partially-checksummed packets, we need to make sure the values
3161 * for skb->csum_start and skb->csum_offset are valid so we don't oops.
3162 *
3163 * This function checks and sets those values and skb->ip_summed: if this
3164 * returns false you should drop the packet.
3165 */
3166bool skb_partial_csum_set(struct sk_buff *skb, u16 start, u16 off)
3167{
3168 if (unlikely(start > skb_headlen(skb)) ||
3169 unlikely((int)start + off > skb_headlen(skb) - 2)) {
3170 if (net_ratelimit())
3171 printk(KERN_WARNING
3172 "bad partial csum: csum=%u/%u len=%u\n",
3173 start, off, skb_headlen(skb));
3174 return false;
3175 }
3176 skb->ip_summed = CHECKSUM_PARTIAL;
3177 skb->csum_start = skb_headroom(skb) + start;
3178 skb->csum_offset = off;
3179 return true;
3180}
3181EXPORT_SYMBOL_GPL(skb_partial_csum_set);
3182
3183void __skb_warn_lro_forwarding(const struct sk_buff *skb)
3184{
3185 if (net_ratelimit())
3186 pr_warning("%s: received packets cannot be forwarded"
3187 " while LRO is enabled\n", skb->dev->name);
3188}
3189EXPORT_SYMBOL(__skb_warn_lro_forwarding);
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/bitfield.h>
62#include <linux/if_vlan.h>
63#include <linux/mpls.h>
64#include <linux/kcov.h>
65#include <linux/iov_iter.h>
66
67#include <net/protocol.h>
68#include <net/dst.h>
69#include <net/sock.h>
70#include <net/checksum.h>
71#include <net/gso.h>
72#include <net/hotdata.h>
73#include <net/ip6_checksum.h>
74#include <net/xfrm.h>
75#include <net/mpls.h>
76#include <net/mptcp.h>
77#include <net/mctp.h>
78#include <net/page_pool/helpers.h>
79#include <net/dropreason.h>
80
81#include <linux/uaccess.h>
82#include <trace/events/skb.h>
83#include <linux/highmem.h>
84#include <linux/capability.h>
85#include <linux/user_namespace.h>
86#include <linux/indirect_call_wrapper.h>
87#include <linux/textsearch.h>
88
89#include "dev.h"
90#include "sock_destructor.h"
91
92#ifdef CONFIG_SKB_EXTENSIONS
93static struct kmem_cache *skbuff_ext_cache __ro_after_init;
94#endif
95
96#define SKB_SMALL_HEAD_SIZE SKB_HEAD_ALIGN(MAX_TCP_HEADER)
97
98/* We want SKB_SMALL_HEAD_CACHE_SIZE to not be a power of two.
99 * This should ensure that SKB_SMALL_HEAD_HEADROOM is a unique
100 * size, and we can differentiate heads from skb_small_head_cache
101 * vs system slabs by looking at their size (skb_end_offset()).
102 */
103#define SKB_SMALL_HEAD_CACHE_SIZE \
104 (is_power_of_2(SKB_SMALL_HEAD_SIZE) ? \
105 (SKB_SMALL_HEAD_SIZE + L1_CACHE_BYTES) : \
106 SKB_SMALL_HEAD_SIZE)
107
108#define SKB_SMALL_HEAD_HEADROOM \
109 SKB_WITH_OVERHEAD(SKB_SMALL_HEAD_CACHE_SIZE)
110
111int sysctl_max_skb_frags __read_mostly = MAX_SKB_FRAGS;
112EXPORT_SYMBOL(sysctl_max_skb_frags);
113
114/* kcm_write_msgs() relies on casting paged frags to bio_vec to use
115 * iov_iter_bvec(). These static asserts ensure the cast is valid is long as the
116 * netmem is a page.
117 */
118static_assert(offsetof(struct bio_vec, bv_page) ==
119 offsetof(skb_frag_t, netmem));
120static_assert(sizeof_field(struct bio_vec, bv_page) ==
121 sizeof_field(skb_frag_t, netmem));
122
123static_assert(offsetof(struct bio_vec, bv_len) == offsetof(skb_frag_t, len));
124static_assert(sizeof_field(struct bio_vec, bv_len) ==
125 sizeof_field(skb_frag_t, len));
126
127static_assert(offsetof(struct bio_vec, bv_offset) ==
128 offsetof(skb_frag_t, offset));
129static_assert(sizeof_field(struct bio_vec, bv_offset) ==
130 sizeof_field(skb_frag_t, offset));
131
132#undef FN
133#define FN(reason) [SKB_DROP_REASON_##reason] = #reason,
134static const char * const drop_reasons[] = {
135 [SKB_CONSUMED] = "CONSUMED",
136 DEFINE_DROP_REASON(FN, FN)
137};
138
139static const struct drop_reason_list drop_reasons_core = {
140 .reasons = drop_reasons,
141 .n_reasons = ARRAY_SIZE(drop_reasons),
142};
143
144const struct drop_reason_list __rcu *
145drop_reasons_by_subsys[SKB_DROP_REASON_SUBSYS_NUM] = {
146 [SKB_DROP_REASON_SUBSYS_CORE] = RCU_INITIALIZER(&drop_reasons_core),
147};
148EXPORT_SYMBOL(drop_reasons_by_subsys);
149
150/**
151 * drop_reasons_register_subsys - register another drop reason subsystem
152 * @subsys: the subsystem to register, must not be the core
153 * @list: the list of drop reasons within the subsystem, must point to
154 * a statically initialized list
155 */
156void drop_reasons_register_subsys(enum skb_drop_reason_subsys subsys,
157 const struct drop_reason_list *list)
158{
159 if (WARN(subsys <= SKB_DROP_REASON_SUBSYS_CORE ||
160 subsys >= ARRAY_SIZE(drop_reasons_by_subsys),
161 "invalid subsystem %d\n", subsys))
162 return;
163
164 /* must point to statically allocated memory, so INIT is OK */
165 RCU_INIT_POINTER(drop_reasons_by_subsys[subsys], list);
166}
167EXPORT_SYMBOL_GPL(drop_reasons_register_subsys);
168
169/**
170 * drop_reasons_unregister_subsys - unregister a drop reason subsystem
171 * @subsys: the subsystem to remove, must not be the core
172 *
173 * Note: This will synchronize_rcu() to ensure no users when it returns.
174 */
175void drop_reasons_unregister_subsys(enum skb_drop_reason_subsys subsys)
176{
177 if (WARN(subsys <= SKB_DROP_REASON_SUBSYS_CORE ||
178 subsys >= ARRAY_SIZE(drop_reasons_by_subsys),
179 "invalid subsystem %d\n", subsys))
180 return;
181
182 RCU_INIT_POINTER(drop_reasons_by_subsys[subsys], NULL);
183
184 synchronize_rcu();
185}
186EXPORT_SYMBOL_GPL(drop_reasons_unregister_subsys);
187
188/**
189 * skb_panic - private function for out-of-line support
190 * @skb: buffer
191 * @sz: size
192 * @addr: address
193 * @msg: skb_over_panic or skb_under_panic
194 *
195 * Out-of-line support for skb_put() and skb_push().
196 * Called via the wrapper skb_over_panic() or skb_under_panic().
197 * Keep out of line to prevent kernel bloat.
198 * __builtin_return_address is not used because it is not always reliable.
199 */
200static void skb_panic(struct sk_buff *skb, unsigned int sz, void *addr,
201 const char msg[])
202{
203 pr_emerg("%s: text:%px len:%d put:%d head:%px data:%px tail:%#lx end:%#lx dev:%s\n",
204 msg, addr, skb->len, sz, skb->head, skb->data,
205 (unsigned long)skb->tail, (unsigned long)skb->end,
206 skb->dev ? skb->dev->name : "<NULL>");
207 BUG();
208}
209
210static void skb_over_panic(struct sk_buff *skb, unsigned int sz, void *addr)
211{
212 skb_panic(skb, sz, addr, __func__);
213}
214
215static void skb_under_panic(struct sk_buff *skb, unsigned int sz, void *addr)
216{
217 skb_panic(skb, sz, addr, __func__);
218}
219
220#define NAPI_SKB_CACHE_SIZE 64
221#define NAPI_SKB_CACHE_BULK 16
222#define NAPI_SKB_CACHE_HALF (NAPI_SKB_CACHE_SIZE / 2)
223
224#if PAGE_SIZE == SZ_4K
225
226#define NAPI_HAS_SMALL_PAGE_FRAG 1
227#define NAPI_SMALL_PAGE_PFMEMALLOC(nc) ((nc).pfmemalloc)
228
229/* specialized page frag allocator using a single order 0 page
230 * and slicing it into 1K sized fragment. Constrained to systems
231 * with a very limited amount of 1K fragments fitting a single
232 * page - to avoid excessive truesize underestimation
233 */
234
235struct page_frag_1k {
236 void *va;
237 u16 offset;
238 bool pfmemalloc;
239};
240
241static void *page_frag_alloc_1k(struct page_frag_1k *nc, gfp_t gfp)
242{
243 struct page *page;
244 int offset;
245
246 offset = nc->offset - SZ_1K;
247 if (likely(offset >= 0))
248 goto use_frag;
249
250 page = alloc_pages_node(NUMA_NO_NODE, gfp, 0);
251 if (!page)
252 return NULL;
253
254 nc->va = page_address(page);
255 nc->pfmemalloc = page_is_pfmemalloc(page);
256 offset = PAGE_SIZE - SZ_1K;
257 page_ref_add(page, offset / SZ_1K);
258
259use_frag:
260 nc->offset = offset;
261 return nc->va + offset;
262}
263#else
264
265/* the small page is actually unused in this build; add dummy helpers
266 * to please the compiler and avoid later preprocessor's conditionals
267 */
268#define NAPI_HAS_SMALL_PAGE_FRAG 0
269#define NAPI_SMALL_PAGE_PFMEMALLOC(nc) false
270
271struct page_frag_1k {
272};
273
274static void *page_frag_alloc_1k(struct page_frag_1k *nc, gfp_t gfp_mask)
275{
276 return NULL;
277}
278
279#endif
280
281struct napi_alloc_cache {
282 struct page_frag_cache page;
283 struct page_frag_1k page_small;
284 unsigned int skb_count;
285 void *skb_cache[NAPI_SKB_CACHE_SIZE];
286};
287
288static DEFINE_PER_CPU(struct page_frag_cache, netdev_alloc_cache);
289static DEFINE_PER_CPU(struct napi_alloc_cache, napi_alloc_cache);
290
291/* Double check that napi_get_frags() allocates skbs with
292 * skb->head being backed by slab, not a page fragment.
293 * This is to make sure bug fixed in 3226b158e67c
294 * ("net: avoid 32 x truesize under-estimation for tiny skbs")
295 * does not accidentally come back.
296 */
297void napi_get_frags_check(struct napi_struct *napi)
298{
299 struct sk_buff *skb;
300
301 local_bh_disable();
302 skb = napi_get_frags(napi);
303 WARN_ON_ONCE(!NAPI_HAS_SMALL_PAGE_FRAG && skb && skb->head_frag);
304 napi_free_frags(napi);
305 local_bh_enable();
306}
307
308void *__napi_alloc_frag_align(unsigned int fragsz, unsigned int align_mask)
309{
310 struct napi_alloc_cache *nc = this_cpu_ptr(&napi_alloc_cache);
311
312 fragsz = SKB_DATA_ALIGN(fragsz);
313
314 return __page_frag_alloc_align(&nc->page, fragsz, GFP_ATOMIC,
315 align_mask);
316}
317EXPORT_SYMBOL(__napi_alloc_frag_align);
318
319void *__netdev_alloc_frag_align(unsigned int fragsz, unsigned int align_mask)
320{
321 void *data;
322
323 fragsz = SKB_DATA_ALIGN(fragsz);
324 if (in_hardirq() || irqs_disabled()) {
325 struct page_frag_cache *nc = this_cpu_ptr(&netdev_alloc_cache);
326
327 data = __page_frag_alloc_align(nc, fragsz, GFP_ATOMIC,
328 align_mask);
329 } else {
330 struct napi_alloc_cache *nc;
331
332 local_bh_disable();
333 nc = this_cpu_ptr(&napi_alloc_cache);
334 data = __page_frag_alloc_align(&nc->page, fragsz, GFP_ATOMIC,
335 align_mask);
336 local_bh_enable();
337 }
338 return data;
339}
340EXPORT_SYMBOL(__netdev_alloc_frag_align);
341
342static struct sk_buff *napi_skb_cache_get(void)
343{
344 struct napi_alloc_cache *nc = this_cpu_ptr(&napi_alloc_cache);
345 struct sk_buff *skb;
346
347 if (unlikely(!nc->skb_count)) {
348 nc->skb_count = kmem_cache_alloc_bulk(net_hotdata.skbuff_cache,
349 GFP_ATOMIC,
350 NAPI_SKB_CACHE_BULK,
351 nc->skb_cache);
352 if (unlikely(!nc->skb_count))
353 return NULL;
354 }
355
356 skb = nc->skb_cache[--nc->skb_count];
357 kasan_mempool_unpoison_object(skb, kmem_cache_size(net_hotdata.skbuff_cache));
358
359 return skb;
360}
361
362static inline void __finalize_skb_around(struct sk_buff *skb, void *data,
363 unsigned int size)
364{
365 struct skb_shared_info *shinfo;
366
367 size -= SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
368
369 /* Assumes caller memset cleared SKB */
370 skb->truesize = SKB_TRUESIZE(size);
371 refcount_set(&skb->users, 1);
372 skb->head = data;
373 skb->data = data;
374 skb_reset_tail_pointer(skb);
375 skb_set_end_offset(skb, size);
376 skb->mac_header = (typeof(skb->mac_header))~0U;
377 skb->transport_header = (typeof(skb->transport_header))~0U;
378 skb->alloc_cpu = raw_smp_processor_id();
379 /* make sure we initialize shinfo sequentially */
380 shinfo = skb_shinfo(skb);
381 memset(shinfo, 0, offsetof(struct skb_shared_info, dataref));
382 atomic_set(&shinfo->dataref, 1);
383
384 skb_set_kcov_handle(skb, kcov_common_handle());
385}
386
387static inline void *__slab_build_skb(struct sk_buff *skb, void *data,
388 unsigned int *size)
389{
390 void *resized;
391
392 /* Must find the allocation size (and grow it to match). */
393 *size = ksize(data);
394 /* krealloc() will immediately return "data" when
395 * "ksize(data)" is requested: it is the existing upper
396 * bounds. As a result, GFP_ATOMIC will be ignored. Note
397 * that this "new" pointer needs to be passed back to the
398 * caller for use so the __alloc_size hinting will be
399 * tracked correctly.
400 */
401 resized = krealloc(data, *size, GFP_ATOMIC);
402 WARN_ON_ONCE(resized != data);
403 return resized;
404}
405
406/* build_skb() variant which can operate on slab buffers.
407 * Note that this should be used sparingly as slab buffers
408 * cannot be combined efficiently by GRO!
409 */
410struct sk_buff *slab_build_skb(void *data)
411{
412 struct sk_buff *skb;
413 unsigned int size;
414
415 skb = kmem_cache_alloc(net_hotdata.skbuff_cache, GFP_ATOMIC);
416 if (unlikely(!skb))
417 return NULL;
418
419 memset(skb, 0, offsetof(struct sk_buff, tail));
420 data = __slab_build_skb(skb, data, &size);
421 __finalize_skb_around(skb, data, size);
422
423 return skb;
424}
425EXPORT_SYMBOL(slab_build_skb);
426
427/* Caller must provide SKB that is memset cleared */
428static void __build_skb_around(struct sk_buff *skb, void *data,
429 unsigned int frag_size)
430{
431 unsigned int size = frag_size;
432
433 /* frag_size == 0 is considered deprecated now. Callers
434 * using slab buffer should use slab_build_skb() instead.
435 */
436 if (WARN_ONCE(size == 0, "Use slab_build_skb() instead"))
437 data = __slab_build_skb(skb, data, &size);
438
439 __finalize_skb_around(skb, data, size);
440}
441
442/**
443 * __build_skb - build a network buffer
444 * @data: data buffer provided by caller
445 * @frag_size: size of data (must not be 0)
446 *
447 * Allocate a new &sk_buff. Caller provides space holding head and
448 * skb_shared_info. @data must have been allocated from the page
449 * allocator or vmalloc(). (A @frag_size of 0 to indicate a kmalloc()
450 * allocation is deprecated, and callers should use slab_build_skb()
451 * instead.)
452 * The return is the new skb buffer.
453 * On a failure the return is %NULL, and @data is not freed.
454 * Notes :
455 * Before IO, driver allocates only data buffer where NIC put incoming frame
456 * Driver should add room at head (NET_SKB_PAD) and
457 * MUST add room at tail (SKB_DATA_ALIGN(skb_shared_info))
458 * After IO, driver calls build_skb(), to allocate sk_buff and populate it
459 * before giving packet to stack.
460 * RX rings only contains data buffers, not full skbs.
461 */
462struct sk_buff *__build_skb(void *data, unsigned int frag_size)
463{
464 struct sk_buff *skb;
465
466 skb = kmem_cache_alloc(net_hotdata.skbuff_cache, GFP_ATOMIC);
467 if (unlikely(!skb))
468 return NULL;
469
470 memset(skb, 0, offsetof(struct sk_buff, tail));
471 __build_skb_around(skb, data, frag_size);
472
473 return skb;
474}
475
476/* build_skb() is wrapper over __build_skb(), that specifically
477 * takes care of skb->head and skb->pfmemalloc
478 */
479struct sk_buff *build_skb(void *data, unsigned int frag_size)
480{
481 struct sk_buff *skb = __build_skb(data, frag_size);
482
483 if (likely(skb && frag_size)) {
484 skb->head_frag = 1;
485 skb_propagate_pfmemalloc(virt_to_head_page(data), skb);
486 }
487 return skb;
488}
489EXPORT_SYMBOL(build_skb);
490
491/**
492 * build_skb_around - build a network buffer around provided skb
493 * @skb: sk_buff provide by caller, must be memset cleared
494 * @data: data buffer provided by caller
495 * @frag_size: size of data
496 */
497struct sk_buff *build_skb_around(struct sk_buff *skb,
498 void *data, unsigned int frag_size)
499{
500 if (unlikely(!skb))
501 return NULL;
502
503 __build_skb_around(skb, data, frag_size);
504
505 if (frag_size) {
506 skb->head_frag = 1;
507 skb_propagate_pfmemalloc(virt_to_head_page(data), skb);
508 }
509 return skb;
510}
511EXPORT_SYMBOL(build_skb_around);
512
513/**
514 * __napi_build_skb - build a network buffer
515 * @data: data buffer provided by caller
516 * @frag_size: size of data
517 *
518 * Version of __build_skb() that uses NAPI percpu caches to obtain
519 * skbuff_head instead of inplace allocation.
520 *
521 * Returns a new &sk_buff on success, %NULL on allocation failure.
522 */
523static struct sk_buff *__napi_build_skb(void *data, unsigned int frag_size)
524{
525 struct sk_buff *skb;
526
527 skb = napi_skb_cache_get();
528 if (unlikely(!skb))
529 return NULL;
530
531 memset(skb, 0, offsetof(struct sk_buff, tail));
532 __build_skb_around(skb, data, frag_size);
533
534 return skb;
535}
536
537/**
538 * napi_build_skb - build a network buffer
539 * @data: data buffer provided by caller
540 * @frag_size: size of data
541 *
542 * Version of __napi_build_skb() that takes care of skb->head_frag
543 * and skb->pfmemalloc when the data is a page or page fragment.
544 *
545 * Returns a new &sk_buff on success, %NULL on allocation failure.
546 */
547struct sk_buff *napi_build_skb(void *data, unsigned int frag_size)
548{
549 struct sk_buff *skb = __napi_build_skb(data, frag_size);
550
551 if (likely(skb) && frag_size) {
552 skb->head_frag = 1;
553 skb_propagate_pfmemalloc(virt_to_head_page(data), skb);
554 }
555
556 return skb;
557}
558EXPORT_SYMBOL(napi_build_skb);
559
560/*
561 * kmalloc_reserve is a wrapper around kmalloc_node_track_caller that tells
562 * the caller if emergency pfmemalloc reserves are being used. If it is and
563 * the socket is later found to be SOCK_MEMALLOC then PFMEMALLOC reserves
564 * may be used. Otherwise, the packet data may be discarded until enough
565 * memory is free
566 */
567static void *kmalloc_reserve(unsigned int *size, gfp_t flags, int node,
568 bool *pfmemalloc)
569{
570 bool ret_pfmemalloc = false;
571 size_t obj_size;
572 void *obj;
573
574 obj_size = SKB_HEAD_ALIGN(*size);
575 if (obj_size <= SKB_SMALL_HEAD_CACHE_SIZE &&
576 !(flags & KMALLOC_NOT_NORMAL_BITS)) {
577 obj = kmem_cache_alloc_node(net_hotdata.skb_small_head_cache,
578 flags | __GFP_NOMEMALLOC | __GFP_NOWARN,
579 node);
580 *size = SKB_SMALL_HEAD_CACHE_SIZE;
581 if (obj || !(gfp_pfmemalloc_allowed(flags)))
582 goto out;
583 /* Try again but now we are using pfmemalloc reserves */
584 ret_pfmemalloc = true;
585 obj = kmem_cache_alloc_node(net_hotdata.skb_small_head_cache, flags, node);
586 goto out;
587 }
588
589 obj_size = kmalloc_size_roundup(obj_size);
590 /* The following cast might truncate high-order bits of obj_size, this
591 * is harmless because kmalloc(obj_size >= 2^32) will fail anyway.
592 */
593 *size = (unsigned int)obj_size;
594
595 /*
596 * Try a regular allocation, when that fails and we're not entitled
597 * to the reserves, fail.
598 */
599 obj = kmalloc_node_track_caller(obj_size,
600 flags | __GFP_NOMEMALLOC | __GFP_NOWARN,
601 node);
602 if (obj || !(gfp_pfmemalloc_allowed(flags)))
603 goto out;
604
605 /* Try again but now we are using pfmemalloc reserves */
606 ret_pfmemalloc = true;
607 obj = kmalloc_node_track_caller(obj_size, flags, node);
608
609out:
610 if (pfmemalloc)
611 *pfmemalloc = ret_pfmemalloc;
612
613 return obj;
614}
615
616/* Allocate a new skbuff. We do this ourselves so we can fill in a few
617 * 'private' fields and also do memory statistics to find all the
618 * [BEEP] leaks.
619 *
620 */
621
622/**
623 * __alloc_skb - allocate a network buffer
624 * @size: size to allocate
625 * @gfp_mask: allocation mask
626 * @flags: If SKB_ALLOC_FCLONE is set, allocate from fclone cache
627 * instead of head cache and allocate a cloned (child) skb.
628 * If SKB_ALLOC_RX is set, __GFP_MEMALLOC will be used for
629 * allocations in case the data is required for writeback
630 * @node: numa node to allocate memory on
631 *
632 * Allocate a new &sk_buff. The returned buffer has no headroom and a
633 * tail room of at least size bytes. The object has a reference count
634 * of one. The return is the buffer. On a failure the return is %NULL.
635 *
636 * Buffers may only be allocated from interrupts using a @gfp_mask of
637 * %GFP_ATOMIC.
638 */
639struct sk_buff *__alloc_skb(unsigned int size, gfp_t gfp_mask,
640 int flags, int node)
641{
642 struct kmem_cache *cache;
643 struct sk_buff *skb;
644 bool pfmemalloc;
645 u8 *data;
646
647 cache = (flags & SKB_ALLOC_FCLONE)
648 ? net_hotdata.skbuff_fclone_cache : net_hotdata.skbuff_cache;
649
650 if (sk_memalloc_socks() && (flags & SKB_ALLOC_RX))
651 gfp_mask |= __GFP_MEMALLOC;
652
653 /* Get the HEAD */
654 if ((flags & (SKB_ALLOC_FCLONE | SKB_ALLOC_NAPI)) == SKB_ALLOC_NAPI &&
655 likely(node == NUMA_NO_NODE || node == numa_mem_id()))
656 skb = napi_skb_cache_get();
657 else
658 skb = kmem_cache_alloc_node(cache, gfp_mask & ~GFP_DMA, node);
659 if (unlikely(!skb))
660 return NULL;
661 prefetchw(skb);
662
663 /* We do our best to align skb_shared_info on a separate cache
664 * line. It usually works because kmalloc(X > SMP_CACHE_BYTES) gives
665 * aligned memory blocks, unless SLUB/SLAB debug is enabled.
666 * Both skb->head and skb_shared_info are cache line aligned.
667 */
668 data = kmalloc_reserve(&size, gfp_mask, node, &pfmemalloc);
669 if (unlikely(!data))
670 goto nodata;
671 /* kmalloc_size_roundup() might give us more room than requested.
672 * Put skb_shared_info exactly at the end of allocated zone,
673 * to allow max possible filling before reallocation.
674 */
675 prefetchw(data + SKB_WITH_OVERHEAD(size));
676
677 /*
678 * Only clear those fields we need to clear, not those that we will
679 * actually initialise below. Hence, don't put any more fields after
680 * the tail pointer in struct sk_buff!
681 */
682 memset(skb, 0, offsetof(struct sk_buff, tail));
683 __build_skb_around(skb, data, size);
684 skb->pfmemalloc = pfmemalloc;
685
686 if (flags & SKB_ALLOC_FCLONE) {
687 struct sk_buff_fclones *fclones;
688
689 fclones = container_of(skb, struct sk_buff_fclones, skb1);
690
691 skb->fclone = SKB_FCLONE_ORIG;
692 refcount_set(&fclones->fclone_ref, 1);
693 }
694
695 return skb;
696
697nodata:
698 kmem_cache_free(cache, skb);
699 return NULL;
700}
701EXPORT_SYMBOL(__alloc_skb);
702
703/**
704 * __netdev_alloc_skb - allocate an skbuff for rx on a specific device
705 * @dev: network device to receive on
706 * @len: length to allocate
707 * @gfp_mask: get_free_pages mask, passed to alloc_skb
708 *
709 * Allocate a new &sk_buff and assign it a usage count of one. The
710 * buffer has NET_SKB_PAD headroom built in. Users should allocate
711 * the headroom they think they need without accounting for the
712 * built in space. The built in space is used for optimisations.
713 *
714 * %NULL is returned if there is no free memory.
715 */
716struct sk_buff *__netdev_alloc_skb(struct net_device *dev, unsigned int len,
717 gfp_t gfp_mask)
718{
719 struct page_frag_cache *nc;
720 struct sk_buff *skb;
721 bool pfmemalloc;
722 void *data;
723
724 len += NET_SKB_PAD;
725
726 /* If requested length is either too small or too big,
727 * we use kmalloc() for skb->head allocation.
728 */
729 if (len <= SKB_WITH_OVERHEAD(1024) ||
730 len > SKB_WITH_OVERHEAD(PAGE_SIZE) ||
731 (gfp_mask & (__GFP_DIRECT_RECLAIM | GFP_DMA))) {
732 skb = __alloc_skb(len, gfp_mask, SKB_ALLOC_RX, NUMA_NO_NODE);
733 if (!skb)
734 goto skb_fail;
735 goto skb_success;
736 }
737
738 len = SKB_HEAD_ALIGN(len);
739
740 if (sk_memalloc_socks())
741 gfp_mask |= __GFP_MEMALLOC;
742
743 if (in_hardirq() || irqs_disabled()) {
744 nc = this_cpu_ptr(&netdev_alloc_cache);
745 data = page_frag_alloc(nc, len, gfp_mask);
746 pfmemalloc = nc->pfmemalloc;
747 } else {
748 local_bh_disable();
749 nc = this_cpu_ptr(&napi_alloc_cache.page);
750 data = page_frag_alloc(nc, len, gfp_mask);
751 pfmemalloc = nc->pfmemalloc;
752 local_bh_enable();
753 }
754
755 if (unlikely(!data))
756 return NULL;
757
758 skb = __build_skb(data, len);
759 if (unlikely(!skb)) {
760 skb_free_frag(data);
761 return NULL;
762 }
763
764 if (pfmemalloc)
765 skb->pfmemalloc = 1;
766 skb->head_frag = 1;
767
768skb_success:
769 skb_reserve(skb, NET_SKB_PAD);
770 skb->dev = dev;
771
772skb_fail:
773 return skb;
774}
775EXPORT_SYMBOL(__netdev_alloc_skb);
776
777/**
778 * __napi_alloc_skb - allocate skbuff for rx in a specific NAPI instance
779 * @napi: napi instance this buffer was allocated for
780 * @len: length to allocate
781 * @gfp_mask: get_free_pages mask, passed to alloc_skb and alloc_pages
782 *
783 * Allocate a new sk_buff for use in NAPI receive. This buffer will
784 * attempt to allocate the head from a special reserved region used
785 * only for NAPI Rx allocation. By doing this we can save several
786 * CPU cycles by avoiding having to disable and re-enable IRQs.
787 *
788 * %NULL is returned if there is no free memory.
789 */
790struct sk_buff *__napi_alloc_skb(struct napi_struct *napi, unsigned int len,
791 gfp_t gfp_mask)
792{
793 struct napi_alloc_cache *nc;
794 struct sk_buff *skb;
795 bool pfmemalloc;
796 void *data;
797
798 DEBUG_NET_WARN_ON_ONCE(!in_softirq());
799 len += NET_SKB_PAD + NET_IP_ALIGN;
800
801 /* If requested length is either too small or too big,
802 * we use kmalloc() for skb->head allocation.
803 * When the small frag allocator is available, prefer it over kmalloc
804 * for small fragments
805 */
806 if ((!NAPI_HAS_SMALL_PAGE_FRAG && len <= SKB_WITH_OVERHEAD(1024)) ||
807 len > SKB_WITH_OVERHEAD(PAGE_SIZE) ||
808 (gfp_mask & (__GFP_DIRECT_RECLAIM | GFP_DMA))) {
809 skb = __alloc_skb(len, gfp_mask, SKB_ALLOC_RX | SKB_ALLOC_NAPI,
810 NUMA_NO_NODE);
811 if (!skb)
812 goto skb_fail;
813 goto skb_success;
814 }
815
816 nc = this_cpu_ptr(&napi_alloc_cache);
817
818 if (sk_memalloc_socks())
819 gfp_mask |= __GFP_MEMALLOC;
820
821 if (NAPI_HAS_SMALL_PAGE_FRAG && len <= SKB_WITH_OVERHEAD(1024)) {
822 /* we are artificially inflating the allocation size, but
823 * that is not as bad as it may look like, as:
824 * - 'len' less than GRO_MAX_HEAD makes little sense
825 * - On most systems, larger 'len' values lead to fragment
826 * size above 512 bytes
827 * - kmalloc would use the kmalloc-1k slab for such values
828 * - Builds with smaller GRO_MAX_HEAD will very likely do
829 * little networking, as that implies no WiFi and no
830 * tunnels support, and 32 bits arches.
831 */
832 len = SZ_1K;
833
834 data = page_frag_alloc_1k(&nc->page_small, gfp_mask);
835 pfmemalloc = NAPI_SMALL_PAGE_PFMEMALLOC(nc->page_small);
836 } else {
837 len = SKB_HEAD_ALIGN(len);
838
839 data = page_frag_alloc(&nc->page, len, gfp_mask);
840 pfmemalloc = nc->page.pfmemalloc;
841 }
842
843 if (unlikely(!data))
844 return NULL;
845
846 skb = __napi_build_skb(data, len);
847 if (unlikely(!skb)) {
848 skb_free_frag(data);
849 return NULL;
850 }
851
852 if (pfmemalloc)
853 skb->pfmemalloc = 1;
854 skb->head_frag = 1;
855
856skb_success:
857 skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN);
858 skb->dev = napi->dev;
859
860skb_fail:
861 return skb;
862}
863EXPORT_SYMBOL(__napi_alloc_skb);
864
865void skb_add_rx_frag_netmem(struct sk_buff *skb, int i, netmem_ref netmem,
866 int off, int size, unsigned int truesize)
867{
868 DEBUG_NET_WARN_ON_ONCE(size > truesize);
869
870 skb_fill_netmem_desc(skb, i, netmem, off, size);
871 skb->len += size;
872 skb->data_len += size;
873 skb->truesize += truesize;
874}
875EXPORT_SYMBOL(skb_add_rx_frag_netmem);
876
877void skb_coalesce_rx_frag(struct sk_buff *skb, int i, int size,
878 unsigned int truesize)
879{
880 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
881
882 DEBUG_NET_WARN_ON_ONCE(size > truesize);
883
884 skb_frag_size_add(frag, size);
885 skb->len += size;
886 skb->data_len += size;
887 skb->truesize += truesize;
888}
889EXPORT_SYMBOL(skb_coalesce_rx_frag);
890
891static void skb_drop_list(struct sk_buff **listp)
892{
893 kfree_skb_list(*listp);
894 *listp = NULL;
895}
896
897static inline void skb_drop_fraglist(struct sk_buff *skb)
898{
899 skb_drop_list(&skb_shinfo(skb)->frag_list);
900}
901
902static void skb_clone_fraglist(struct sk_buff *skb)
903{
904 struct sk_buff *list;
905
906 skb_walk_frags(skb, list)
907 skb_get(list);
908}
909
910static bool is_pp_page(struct page *page)
911{
912 return (page->pp_magic & ~0x3UL) == PP_SIGNATURE;
913}
914
915int skb_pp_cow_data(struct page_pool *pool, struct sk_buff **pskb,
916 unsigned int headroom)
917{
918#if IS_ENABLED(CONFIG_PAGE_POOL)
919 u32 size, truesize, len, max_head_size, off;
920 struct sk_buff *skb = *pskb, *nskb;
921 int err, i, head_off;
922 void *data;
923
924 /* XDP does not support fraglist so we need to linearize
925 * the skb.
926 */
927 if (skb_has_frag_list(skb))
928 return -EOPNOTSUPP;
929
930 max_head_size = SKB_WITH_OVERHEAD(PAGE_SIZE - headroom);
931 if (skb->len > max_head_size + MAX_SKB_FRAGS * PAGE_SIZE)
932 return -ENOMEM;
933
934 size = min_t(u32, skb->len, max_head_size);
935 truesize = SKB_HEAD_ALIGN(size) + headroom;
936 data = page_pool_dev_alloc_va(pool, &truesize);
937 if (!data)
938 return -ENOMEM;
939
940 nskb = napi_build_skb(data, truesize);
941 if (!nskb) {
942 page_pool_free_va(pool, data, true);
943 return -ENOMEM;
944 }
945
946 skb_reserve(nskb, headroom);
947 skb_copy_header(nskb, skb);
948 skb_mark_for_recycle(nskb);
949
950 err = skb_copy_bits(skb, 0, nskb->data, size);
951 if (err) {
952 consume_skb(nskb);
953 return err;
954 }
955 skb_put(nskb, size);
956
957 head_off = skb_headroom(nskb) - skb_headroom(skb);
958 skb_headers_offset_update(nskb, head_off);
959
960 off = size;
961 len = skb->len - off;
962 for (i = 0; i < MAX_SKB_FRAGS && off < skb->len; i++) {
963 struct page *page;
964 u32 page_off;
965
966 size = min_t(u32, len, PAGE_SIZE);
967 truesize = size;
968
969 page = page_pool_dev_alloc(pool, &page_off, &truesize);
970 if (!page) {
971 consume_skb(nskb);
972 return -ENOMEM;
973 }
974
975 skb_add_rx_frag(nskb, i, page, page_off, size, truesize);
976 err = skb_copy_bits(skb, off, page_address(page) + page_off,
977 size);
978 if (err) {
979 consume_skb(nskb);
980 return err;
981 }
982
983 len -= size;
984 off += size;
985 }
986
987 consume_skb(skb);
988 *pskb = nskb;
989
990 return 0;
991#else
992 return -EOPNOTSUPP;
993#endif
994}
995EXPORT_SYMBOL(skb_pp_cow_data);
996
997int skb_cow_data_for_xdp(struct page_pool *pool, struct sk_buff **pskb,
998 struct bpf_prog *prog)
999{
1000 if (!prog->aux->xdp_has_frags)
1001 return -EINVAL;
1002
1003 return skb_pp_cow_data(pool, pskb, XDP_PACKET_HEADROOM);
1004}
1005EXPORT_SYMBOL(skb_cow_data_for_xdp);
1006
1007#if IS_ENABLED(CONFIG_PAGE_POOL)
1008bool napi_pp_put_page(struct page *page, bool napi_safe)
1009{
1010 bool allow_direct = false;
1011 struct page_pool *pp;
1012
1013 page = compound_head(page);
1014
1015 /* page->pp_magic is OR'ed with PP_SIGNATURE after the allocation
1016 * in order to preserve any existing bits, such as bit 0 for the
1017 * head page of compound page and bit 1 for pfmemalloc page, so
1018 * mask those bits for freeing side when doing below checking,
1019 * and page_is_pfmemalloc() is checked in __page_pool_put_page()
1020 * to avoid recycling the pfmemalloc page.
1021 */
1022 if (unlikely(!is_pp_page(page)))
1023 return false;
1024
1025 pp = page->pp;
1026
1027 /* Allow direct recycle if we have reasons to believe that we are
1028 * in the same context as the consumer would run, so there's
1029 * no possible race.
1030 * __page_pool_put_page() makes sure we're not in hardirq context
1031 * and interrupts are enabled prior to accessing the cache.
1032 */
1033 if (napi_safe || in_softirq()) {
1034 const struct napi_struct *napi = READ_ONCE(pp->p.napi);
1035 unsigned int cpuid = smp_processor_id();
1036
1037 allow_direct = napi && READ_ONCE(napi->list_owner) == cpuid;
1038 allow_direct |= READ_ONCE(pp->cpuid) == cpuid;
1039 }
1040
1041 /* Driver set this to memory recycling info. Reset it on recycle.
1042 * This will *not* work for NIC using a split-page memory model.
1043 * The page will be returned to the pool here regardless of the
1044 * 'flipped' fragment being in use or not.
1045 */
1046 page_pool_put_full_page(pp, page, allow_direct);
1047
1048 return true;
1049}
1050EXPORT_SYMBOL(napi_pp_put_page);
1051#endif
1052
1053static bool skb_pp_recycle(struct sk_buff *skb, void *data, bool napi_safe)
1054{
1055 if (!IS_ENABLED(CONFIG_PAGE_POOL) || !skb->pp_recycle)
1056 return false;
1057 return napi_pp_put_page(virt_to_page(data), napi_safe);
1058}
1059
1060/**
1061 * skb_pp_frag_ref() - Increase fragment references of a page pool aware skb
1062 * @skb: page pool aware skb
1063 *
1064 * Increase the fragment reference count (pp_ref_count) of a skb. This is
1065 * intended to gain fragment references only for page pool aware skbs,
1066 * i.e. when skb->pp_recycle is true, and not for fragments in a
1067 * non-pp-recycling skb. It has a fallback to increase references on normal
1068 * pages, as page pool aware skbs may also have normal page fragments.
1069 */
1070static int skb_pp_frag_ref(struct sk_buff *skb)
1071{
1072 struct skb_shared_info *shinfo;
1073 struct page *head_page;
1074 int i;
1075
1076 if (!skb->pp_recycle)
1077 return -EINVAL;
1078
1079 shinfo = skb_shinfo(skb);
1080
1081 for (i = 0; i < shinfo->nr_frags; i++) {
1082 head_page = compound_head(skb_frag_page(&shinfo->frags[i]));
1083 if (likely(is_pp_page(head_page)))
1084 page_pool_ref_page(head_page);
1085 else
1086 page_ref_inc(head_page);
1087 }
1088 return 0;
1089}
1090
1091static void skb_kfree_head(void *head, unsigned int end_offset)
1092{
1093 if (end_offset == SKB_SMALL_HEAD_HEADROOM)
1094 kmem_cache_free(net_hotdata.skb_small_head_cache, head);
1095 else
1096 kfree(head);
1097}
1098
1099static void skb_free_head(struct sk_buff *skb, bool napi_safe)
1100{
1101 unsigned char *head = skb->head;
1102
1103 if (skb->head_frag) {
1104 if (skb_pp_recycle(skb, head, napi_safe))
1105 return;
1106 skb_free_frag(head);
1107 } else {
1108 skb_kfree_head(head, skb_end_offset(skb));
1109 }
1110}
1111
1112static void skb_release_data(struct sk_buff *skb, enum skb_drop_reason reason,
1113 bool napi_safe)
1114{
1115 struct skb_shared_info *shinfo = skb_shinfo(skb);
1116 int i;
1117
1118 if (!skb_data_unref(skb, shinfo))
1119 goto exit;
1120
1121 if (skb_zcopy(skb)) {
1122 bool skip_unref = shinfo->flags & SKBFL_MANAGED_FRAG_REFS;
1123
1124 skb_zcopy_clear(skb, true);
1125 if (skip_unref)
1126 goto free_head;
1127 }
1128
1129 for (i = 0; i < shinfo->nr_frags; i++)
1130 napi_frag_unref(&shinfo->frags[i], skb->pp_recycle, napi_safe);
1131
1132free_head:
1133 if (shinfo->frag_list)
1134 kfree_skb_list_reason(shinfo->frag_list, reason);
1135
1136 skb_free_head(skb, napi_safe);
1137exit:
1138 /* When we clone an SKB we copy the reycling bit. The pp_recycle
1139 * bit is only set on the head though, so in order to avoid races
1140 * while trying to recycle fragments on __skb_frag_unref() we need
1141 * to make one SKB responsible for triggering the recycle path.
1142 * So disable the recycling bit if an SKB is cloned and we have
1143 * additional references to the fragmented part of the SKB.
1144 * Eventually the last SKB will have the recycling bit set and it's
1145 * dataref set to 0, which will trigger the recycling
1146 */
1147 skb->pp_recycle = 0;
1148}
1149
1150/*
1151 * Free an skbuff by memory without cleaning the state.
1152 */
1153static void kfree_skbmem(struct sk_buff *skb)
1154{
1155 struct sk_buff_fclones *fclones;
1156
1157 switch (skb->fclone) {
1158 case SKB_FCLONE_UNAVAILABLE:
1159 kmem_cache_free(net_hotdata.skbuff_cache, skb);
1160 return;
1161
1162 case SKB_FCLONE_ORIG:
1163 fclones = container_of(skb, struct sk_buff_fclones, skb1);
1164
1165 /* We usually free the clone (TX completion) before original skb
1166 * This test would have no chance to be true for the clone,
1167 * while here, branch prediction will be good.
1168 */
1169 if (refcount_read(&fclones->fclone_ref) == 1)
1170 goto fastpath;
1171 break;
1172
1173 default: /* SKB_FCLONE_CLONE */
1174 fclones = container_of(skb, struct sk_buff_fclones, skb2);
1175 break;
1176 }
1177 if (!refcount_dec_and_test(&fclones->fclone_ref))
1178 return;
1179fastpath:
1180 kmem_cache_free(net_hotdata.skbuff_fclone_cache, fclones);
1181}
1182
1183void skb_release_head_state(struct sk_buff *skb)
1184{
1185 skb_dst_drop(skb);
1186 if (skb->destructor) {
1187 DEBUG_NET_WARN_ON_ONCE(in_hardirq());
1188 skb->destructor(skb);
1189 }
1190#if IS_ENABLED(CONFIG_NF_CONNTRACK)
1191 nf_conntrack_put(skb_nfct(skb));
1192#endif
1193 skb_ext_put(skb);
1194}
1195
1196/* Free everything but the sk_buff shell. */
1197static void skb_release_all(struct sk_buff *skb, enum skb_drop_reason reason,
1198 bool napi_safe)
1199{
1200 skb_release_head_state(skb);
1201 if (likely(skb->head))
1202 skb_release_data(skb, reason, napi_safe);
1203}
1204
1205/**
1206 * __kfree_skb - private function
1207 * @skb: buffer
1208 *
1209 * Free an sk_buff. Release anything attached to the buffer.
1210 * Clean the state. This is an internal helper function. Users should
1211 * always call kfree_skb
1212 */
1213
1214void __kfree_skb(struct sk_buff *skb)
1215{
1216 skb_release_all(skb, SKB_DROP_REASON_NOT_SPECIFIED, false);
1217 kfree_skbmem(skb);
1218}
1219EXPORT_SYMBOL(__kfree_skb);
1220
1221static __always_inline
1222bool __kfree_skb_reason(struct sk_buff *skb, enum skb_drop_reason reason)
1223{
1224 if (unlikely(!skb_unref(skb)))
1225 return false;
1226
1227 DEBUG_NET_WARN_ON_ONCE(reason == SKB_NOT_DROPPED_YET ||
1228 u32_get_bits(reason,
1229 SKB_DROP_REASON_SUBSYS_MASK) >=
1230 SKB_DROP_REASON_SUBSYS_NUM);
1231
1232 if (reason == SKB_CONSUMED)
1233 trace_consume_skb(skb, __builtin_return_address(0));
1234 else
1235 trace_kfree_skb(skb, __builtin_return_address(0), reason);
1236 return true;
1237}
1238
1239/**
1240 * kfree_skb_reason - free an sk_buff with special reason
1241 * @skb: buffer to free
1242 * @reason: reason why this skb is dropped
1243 *
1244 * Drop a reference to the buffer and free it if the usage count has
1245 * hit zero. Meanwhile, pass the drop reason to 'kfree_skb'
1246 * tracepoint.
1247 */
1248void __fix_address
1249kfree_skb_reason(struct sk_buff *skb, enum skb_drop_reason reason)
1250{
1251 if (__kfree_skb_reason(skb, reason))
1252 __kfree_skb(skb);
1253}
1254EXPORT_SYMBOL(kfree_skb_reason);
1255
1256#define KFREE_SKB_BULK_SIZE 16
1257
1258struct skb_free_array {
1259 unsigned int skb_count;
1260 void *skb_array[KFREE_SKB_BULK_SIZE];
1261};
1262
1263static void kfree_skb_add_bulk(struct sk_buff *skb,
1264 struct skb_free_array *sa,
1265 enum skb_drop_reason reason)
1266{
1267 /* if SKB is a clone, don't handle this case */
1268 if (unlikely(skb->fclone != SKB_FCLONE_UNAVAILABLE)) {
1269 __kfree_skb(skb);
1270 return;
1271 }
1272
1273 skb_release_all(skb, reason, false);
1274 sa->skb_array[sa->skb_count++] = skb;
1275
1276 if (unlikely(sa->skb_count == KFREE_SKB_BULK_SIZE)) {
1277 kmem_cache_free_bulk(net_hotdata.skbuff_cache, KFREE_SKB_BULK_SIZE,
1278 sa->skb_array);
1279 sa->skb_count = 0;
1280 }
1281}
1282
1283void __fix_address
1284kfree_skb_list_reason(struct sk_buff *segs, enum skb_drop_reason reason)
1285{
1286 struct skb_free_array sa;
1287
1288 sa.skb_count = 0;
1289
1290 while (segs) {
1291 struct sk_buff *next = segs->next;
1292
1293 if (__kfree_skb_reason(segs, reason)) {
1294 skb_poison_list(segs);
1295 kfree_skb_add_bulk(segs, &sa, reason);
1296 }
1297
1298 segs = next;
1299 }
1300
1301 if (sa.skb_count)
1302 kmem_cache_free_bulk(net_hotdata.skbuff_cache, sa.skb_count, sa.skb_array);
1303}
1304EXPORT_SYMBOL(kfree_skb_list_reason);
1305
1306/* Dump skb information and contents.
1307 *
1308 * Must only be called from net_ratelimit()-ed paths.
1309 *
1310 * Dumps whole packets if full_pkt, only headers otherwise.
1311 */
1312void skb_dump(const char *level, const struct sk_buff *skb, bool full_pkt)
1313{
1314 struct skb_shared_info *sh = skb_shinfo(skb);
1315 struct net_device *dev = skb->dev;
1316 struct sock *sk = skb->sk;
1317 struct sk_buff *list_skb;
1318 bool has_mac, has_trans;
1319 int headroom, tailroom;
1320 int i, len, seg_len;
1321
1322 if (full_pkt)
1323 len = skb->len;
1324 else
1325 len = min_t(int, skb->len, MAX_HEADER + 128);
1326
1327 headroom = skb_headroom(skb);
1328 tailroom = skb_tailroom(skb);
1329
1330 has_mac = skb_mac_header_was_set(skb);
1331 has_trans = skb_transport_header_was_set(skb);
1332
1333 printk("%sskb len=%u headroom=%u headlen=%u tailroom=%u\n"
1334 "mac=(%d,%d) net=(%d,%d) trans=%d\n"
1335 "shinfo(txflags=%u nr_frags=%u gso(size=%hu type=%u segs=%hu))\n"
1336 "csum(0x%x ip_summed=%u complete_sw=%u valid=%u level=%u)\n"
1337 "hash(0x%x sw=%u l4=%u) proto=0x%04x pkttype=%u iif=%d\n",
1338 level, skb->len, headroom, skb_headlen(skb), tailroom,
1339 has_mac ? skb->mac_header : -1,
1340 has_mac ? skb_mac_header_len(skb) : -1,
1341 skb->network_header,
1342 has_trans ? skb_network_header_len(skb) : -1,
1343 has_trans ? skb->transport_header : -1,
1344 sh->tx_flags, sh->nr_frags,
1345 sh->gso_size, sh->gso_type, sh->gso_segs,
1346 skb->csum, skb->ip_summed, skb->csum_complete_sw,
1347 skb->csum_valid, skb->csum_level,
1348 skb->hash, skb->sw_hash, skb->l4_hash,
1349 ntohs(skb->protocol), skb->pkt_type, skb->skb_iif);
1350
1351 if (dev)
1352 printk("%sdev name=%s feat=%pNF\n",
1353 level, dev->name, &dev->features);
1354 if (sk)
1355 printk("%ssk family=%hu type=%u proto=%u\n",
1356 level, sk->sk_family, sk->sk_type, sk->sk_protocol);
1357
1358 if (full_pkt && headroom)
1359 print_hex_dump(level, "skb headroom: ", DUMP_PREFIX_OFFSET,
1360 16, 1, skb->head, headroom, false);
1361
1362 seg_len = min_t(int, skb_headlen(skb), len);
1363 if (seg_len)
1364 print_hex_dump(level, "skb linear: ", DUMP_PREFIX_OFFSET,
1365 16, 1, skb->data, seg_len, false);
1366 len -= seg_len;
1367
1368 if (full_pkt && tailroom)
1369 print_hex_dump(level, "skb tailroom: ", DUMP_PREFIX_OFFSET,
1370 16, 1, skb_tail_pointer(skb), tailroom, false);
1371
1372 for (i = 0; len && i < skb_shinfo(skb)->nr_frags; i++) {
1373 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
1374 u32 p_off, p_len, copied;
1375 struct page *p;
1376 u8 *vaddr;
1377
1378 skb_frag_foreach_page(frag, skb_frag_off(frag),
1379 skb_frag_size(frag), p, p_off, p_len,
1380 copied) {
1381 seg_len = min_t(int, p_len, len);
1382 vaddr = kmap_atomic(p);
1383 print_hex_dump(level, "skb frag: ",
1384 DUMP_PREFIX_OFFSET,
1385 16, 1, vaddr + p_off, seg_len, false);
1386 kunmap_atomic(vaddr);
1387 len -= seg_len;
1388 if (!len)
1389 break;
1390 }
1391 }
1392
1393 if (full_pkt && skb_has_frag_list(skb)) {
1394 printk("skb fraglist:\n");
1395 skb_walk_frags(skb, list_skb)
1396 skb_dump(level, list_skb, true);
1397 }
1398}
1399EXPORT_SYMBOL(skb_dump);
1400
1401/**
1402 * skb_tx_error - report an sk_buff xmit error
1403 * @skb: buffer that triggered an error
1404 *
1405 * Report xmit error if a device callback is tracking this skb.
1406 * skb must be freed afterwards.
1407 */
1408void skb_tx_error(struct sk_buff *skb)
1409{
1410 if (skb) {
1411 skb_zcopy_downgrade_managed(skb);
1412 skb_zcopy_clear(skb, true);
1413 }
1414}
1415EXPORT_SYMBOL(skb_tx_error);
1416
1417#ifdef CONFIG_TRACEPOINTS
1418/**
1419 * consume_skb - free an skbuff
1420 * @skb: buffer to free
1421 *
1422 * Drop a ref to the buffer and free it if the usage count has hit zero
1423 * Functions identically to kfree_skb, but kfree_skb assumes that the frame
1424 * is being dropped after a failure and notes that
1425 */
1426void consume_skb(struct sk_buff *skb)
1427{
1428 if (!skb_unref(skb))
1429 return;
1430
1431 trace_consume_skb(skb, __builtin_return_address(0));
1432 __kfree_skb(skb);
1433}
1434EXPORT_SYMBOL(consume_skb);
1435#endif
1436
1437/**
1438 * __consume_stateless_skb - free an skbuff, assuming it is stateless
1439 * @skb: buffer to free
1440 *
1441 * Alike consume_skb(), but this variant assumes that this is the last
1442 * skb reference and all the head states have been already dropped
1443 */
1444void __consume_stateless_skb(struct sk_buff *skb)
1445{
1446 trace_consume_skb(skb, __builtin_return_address(0));
1447 skb_release_data(skb, SKB_CONSUMED, false);
1448 kfree_skbmem(skb);
1449}
1450
1451static void napi_skb_cache_put(struct sk_buff *skb)
1452{
1453 struct napi_alloc_cache *nc = this_cpu_ptr(&napi_alloc_cache);
1454 u32 i;
1455
1456 if (!kasan_mempool_poison_object(skb))
1457 return;
1458
1459 nc->skb_cache[nc->skb_count++] = skb;
1460
1461 if (unlikely(nc->skb_count == NAPI_SKB_CACHE_SIZE)) {
1462 for (i = NAPI_SKB_CACHE_HALF; i < NAPI_SKB_CACHE_SIZE; i++)
1463 kasan_mempool_unpoison_object(nc->skb_cache[i],
1464 kmem_cache_size(net_hotdata.skbuff_cache));
1465
1466 kmem_cache_free_bulk(net_hotdata.skbuff_cache, NAPI_SKB_CACHE_HALF,
1467 nc->skb_cache + NAPI_SKB_CACHE_HALF);
1468 nc->skb_count = NAPI_SKB_CACHE_HALF;
1469 }
1470}
1471
1472void __napi_kfree_skb(struct sk_buff *skb, enum skb_drop_reason reason)
1473{
1474 skb_release_all(skb, reason, true);
1475 napi_skb_cache_put(skb);
1476}
1477
1478void napi_skb_free_stolen_head(struct sk_buff *skb)
1479{
1480 if (unlikely(skb->slow_gro)) {
1481 nf_reset_ct(skb);
1482 skb_dst_drop(skb);
1483 skb_ext_put(skb);
1484 skb_orphan(skb);
1485 skb->slow_gro = 0;
1486 }
1487 napi_skb_cache_put(skb);
1488}
1489
1490void napi_consume_skb(struct sk_buff *skb, int budget)
1491{
1492 /* Zero budget indicate non-NAPI context called us, like netpoll */
1493 if (unlikely(!budget)) {
1494 dev_consume_skb_any(skb);
1495 return;
1496 }
1497
1498 DEBUG_NET_WARN_ON_ONCE(!in_softirq());
1499
1500 if (!skb_unref(skb))
1501 return;
1502
1503 /* if reaching here SKB is ready to free */
1504 trace_consume_skb(skb, __builtin_return_address(0));
1505
1506 /* if SKB is a clone, don't handle this case */
1507 if (skb->fclone != SKB_FCLONE_UNAVAILABLE) {
1508 __kfree_skb(skb);
1509 return;
1510 }
1511
1512 skb_release_all(skb, SKB_CONSUMED, !!budget);
1513 napi_skb_cache_put(skb);
1514}
1515EXPORT_SYMBOL(napi_consume_skb);
1516
1517/* Make sure a field is contained by headers group */
1518#define CHECK_SKB_FIELD(field) \
1519 BUILD_BUG_ON(offsetof(struct sk_buff, field) != \
1520 offsetof(struct sk_buff, headers.field)); \
1521
1522static void __copy_skb_header(struct sk_buff *new, const struct sk_buff *old)
1523{
1524 new->tstamp = old->tstamp;
1525 /* We do not copy old->sk */
1526 new->dev = old->dev;
1527 memcpy(new->cb, old->cb, sizeof(old->cb));
1528 skb_dst_copy(new, old);
1529 __skb_ext_copy(new, old);
1530 __nf_copy(new, old, false);
1531
1532 /* Note : this field could be in the headers group.
1533 * It is not yet because we do not want to have a 16 bit hole
1534 */
1535 new->queue_mapping = old->queue_mapping;
1536
1537 memcpy(&new->headers, &old->headers, sizeof(new->headers));
1538 CHECK_SKB_FIELD(protocol);
1539 CHECK_SKB_FIELD(csum);
1540 CHECK_SKB_FIELD(hash);
1541 CHECK_SKB_FIELD(priority);
1542 CHECK_SKB_FIELD(skb_iif);
1543 CHECK_SKB_FIELD(vlan_proto);
1544 CHECK_SKB_FIELD(vlan_tci);
1545 CHECK_SKB_FIELD(transport_header);
1546 CHECK_SKB_FIELD(network_header);
1547 CHECK_SKB_FIELD(mac_header);
1548 CHECK_SKB_FIELD(inner_protocol);
1549 CHECK_SKB_FIELD(inner_transport_header);
1550 CHECK_SKB_FIELD(inner_network_header);
1551 CHECK_SKB_FIELD(inner_mac_header);
1552 CHECK_SKB_FIELD(mark);
1553#ifdef CONFIG_NETWORK_SECMARK
1554 CHECK_SKB_FIELD(secmark);
1555#endif
1556#ifdef CONFIG_NET_RX_BUSY_POLL
1557 CHECK_SKB_FIELD(napi_id);
1558#endif
1559 CHECK_SKB_FIELD(alloc_cpu);
1560#ifdef CONFIG_XPS
1561 CHECK_SKB_FIELD(sender_cpu);
1562#endif
1563#ifdef CONFIG_NET_SCHED
1564 CHECK_SKB_FIELD(tc_index);
1565#endif
1566
1567}
1568
1569/*
1570 * You should not add any new code to this function. Add it to
1571 * __copy_skb_header above instead.
1572 */
1573static struct sk_buff *__skb_clone(struct sk_buff *n, struct sk_buff *skb)
1574{
1575#define C(x) n->x = skb->x
1576
1577 n->next = n->prev = NULL;
1578 n->sk = NULL;
1579 __copy_skb_header(n, skb);
1580
1581 C(len);
1582 C(data_len);
1583 C(mac_len);
1584 n->hdr_len = skb->nohdr ? skb_headroom(skb) : skb->hdr_len;
1585 n->cloned = 1;
1586 n->nohdr = 0;
1587 n->peeked = 0;
1588 C(pfmemalloc);
1589 C(pp_recycle);
1590 n->destructor = NULL;
1591 C(tail);
1592 C(end);
1593 C(head);
1594 C(head_frag);
1595 C(data);
1596 C(truesize);
1597 refcount_set(&n->users, 1);
1598
1599 atomic_inc(&(skb_shinfo(skb)->dataref));
1600 skb->cloned = 1;
1601
1602 return n;
1603#undef C
1604}
1605
1606/**
1607 * alloc_skb_for_msg() - allocate sk_buff to wrap frag list forming a msg
1608 * @first: first sk_buff of the msg
1609 */
1610struct sk_buff *alloc_skb_for_msg(struct sk_buff *first)
1611{
1612 struct sk_buff *n;
1613
1614 n = alloc_skb(0, GFP_ATOMIC);
1615 if (!n)
1616 return NULL;
1617
1618 n->len = first->len;
1619 n->data_len = first->len;
1620 n->truesize = first->truesize;
1621
1622 skb_shinfo(n)->frag_list = first;
1623
1624 __copy_skb_header(n, first);
1625 n->destructor = NULL;
1626
1627 return n;
1628}
1629EXPORT_SYMBOL_GPL(alloc_skb_for_msg);
1630
1631/**
1632 * skb_morph - morph one skb into another
1633 * @dst: the skb to receive the contents
1634 * @src: the skb to supply the contents
1635 *
1636 * This is identical to skb_clone except that the target skb is
1637 * supplied by the user.
1638 *
1639 * The target skb is returned upon exit.
1640 */
1641struct sk_buff *skb_morph(struct sk_buff *dst, struct sk_buff *src)
1642{
1643 skb_release_all(dst, SKB_CONSUMED, false);
1644 return __skb_clone(dst, src);
1645}
1646EXPORT_SYMBOL_GPL(skb_morph);
1647
1648int mm_account_pinned_pages(struct mmpin *mmp, size_t size)
1649{
1650 unsigned long max_pg, num_pg, new_pg, old_pg, rlim;
1651 struct user_struct *user;
1652
1653 if (capable(CAP_IPC_LOCK) || !size)
1654 return 0;
1655
1656 rlim = rlimit(RLIMIT_MEMLOCK);
1657 if (rlim == RLIM_INFINITY)
1658 return 0;
1659
1660 num_pg = (size >> PAGE_SHIFT) + 2; /* worst case */
1661 max_pg = rlim >> PAGE_SHIFT;
1662 user = mmp->user ? : current_user();
1663
1664 old_pg = atomic_long_read(&user->locked_vm);
1665 do {
1666 new_pg = old_pg + num_pg;
1667 if (new_pg > max_pg)
1668 return -ENOBUFS;
1669 } while (!atomic_long_try_cmpxchg(&user->locked_vm, &old_pg, new_pg));
1670
1671 if (!mmp->user) {
1672 mmp->user = get_uid(user);
1673 mmp->num_pg = num_pg;
1674 } else {
1675 mmp->num_pg += num_pg;
1676 }
1677
1678 return 0;
1679}
1680EXPORT_SYMBOL_GPL(mm_account_pinned_pages);
1681
1682void mm_unaccount_pinned_pages(struct mmpin *mmp)
1683{
1684 if (mmp->user) {
1685 atomic_long_sub(mmp->num_pg, &mmp->user->locked_vm);
1686 free_uid(mmp->user);
1687 }
1688}
1689EXPORT_SYMBOL_GPL(mm_unaccount_pinned_pages);
1690
1691static struct ubuf_info *msg_zerocopy_alloc(struct sock *sk, size_t size)
1692{
1693 struct ubuf_info_msgzc *uarg;
1694 struct sk_buff *skb;
1695
1696 WARN_ON_ONCE(!in_task());
1697
1698 skb = sock_omalloc(sk, 0, GFP_KERNEL);
1699 if (!skb)
1700 return NULL;
1701
1702 BUILD_BUG_ON(sizeof(*uarg) > sizeof(skb->cb));
1703 uarg = (void *)skb->cb;
1704 uarg->mmp.user = NULL;
1705
1706 if (mm_account_pinned_pages(&uarg->mmp, size)) {
1707 kfree_skb(skb);
1708 return NULL;
1709 }
1710
1711 uarg->ubuf.callback = msg_zerocopy_callback;
1712 uarg->id = ((u32)atomic_inc_return(&sk->sk_zckey)) - 1;
1713 uarg->len = 1;
1714 uarg->bytelen = size;
1715 uarg->zerocopy = 1;
1716 uarg->ubuf.flags = SKBFL_ZEROCOPY_FRAG | SKBFL_DONT_ORPHAN;
1717 refcount_set(&uarg->ubuf.refcnt, 1);
1718 sock_hold(sk);
1719
1720 return &uarg->ubuf;
1721}
1722
1723static inline struct sk_buff *skb_from_uarg(struct ubuf_info_msgzc *uarg)
1724{
1725 return container_of((void *)uarg, struct sk_buff, cb);
1726}
1727
1728struct ubuf_info *msg_zerocopy_realloc(struct sock *sk, size_t size,
1729 struct ubuf_info *uarg)
1730{
1731 if (uarg) {
1732 struct ubuf_info_msgzc *uarg_zc;
1733 const u32 byte_limit = 1 << 19; /* limit to a few TSO */
1734 u32 bytelen, next;
1735
1736 /* there might be non MSG_ZEROCOPY users */
1737 if (uarg->callback != msg_zerocopy_callback)
1738 return NULL;
1739
1740 /* realloc only when socket is locked (TCP, UDP cork),
1741 * so uarg->len and sk_zckey access is serialized
1742 */
1743 if (!sock_owned_by_user(sk)) {
1744 WARN_ON_ONCE(1);
1745 return NULL;
1746 }
1747
1748 uarg_zc = uarg_to_msgzc(uarg);
1749 bytelen = uarg_zc->bytelen + size;
1750 if (uarg_zc->len == USHRT_MAX - 1 || bytelen > byte_limit) {
1751 /* TCP can create new skb to attach new uarg */
1752 if (sk->sk_type == SOCK_STREAM)
1753 goto new_alloc;
1754 return NULL;
1755 }
1756
1757 next = (u32)atomic_read(&sk->sk_zckey);
1758 if ((u32)(uarg_zc->id + uarg_zc->len) == next) {
1759 if (mm_account_pinned_pages(&uarg_zc->mmp, size))
1760 return NULL;
1761 uarg_zc->len++;
1762 uarg_zc->bytelen = bytelen;
1763 atomic_set(&sk->sk_zckey, ++next);
1764
1765 /* no extra ref when appending to datagram (MSG_MORE) */
1766 if (sk->sk_type == SOCK_STREAM)
1767 net_zcopy_get(uarg);
1768
1769 return uarg;
1770 }
1771 }
1772
1773new_alloc:
1774 return msg_zerocopy_alloc(sk, size);
1775}
1776EXPORT_SYMBOL_GPL(msg_zerocopy_realloc);
1777
1778static bool skb_zerocopy_notify_extend(struct sk_buff *skb, u32 lo, u16 len)
1779{
1780 struct sock_exterr_skb *serr = SKB_EXT_ERR(skb);
1781 u32 old_lo, old_hi;
1782 u64 sum_len;
1783
1784 old_lo = serr->ee.ee_info;
1785 old_hi = serr->ee.ee_data;
1786 sum_len = old_hi - old_lo + 1ULL + len;
1787
1788 if (sum_len >= (1ULL << 32))
1789 return false;
1790
1791 if (lo != old_hi + 1)
1792 return false;
1793
1794 serr->ee.ee_data += len;
1795 return true;
1796}
1797
1798static void __msg_zerocopy_callback(struct ubuf_info_msgzc *uarg)
1799{
1800 struct sk_buff *tail, *skb = skb_from_uarg(uarg);
1801 struct sock_exterr_skb *serr;
1802 struct sock *sk = skb->sk;
1803 struct sk_buff_head *q;
1804 unsigned long flags;
1805 bool is_zerocopy;
1806 u32 lo, hi;
1807 u16 len;
1808
1809 mm_unaccount_pinned_pages(&uarg->mmp);
1810
1811 /* if !len, there was only 1 call, and it was aborted
1812 * so do not queue a completion notification
1813 */
1814 if (!uarg->len || sock_flag(sk, SOCK_DEAD))
1815 goto release;
1816
1817 len = uarg->len;
1818 lo = uarg->id;
1819 hi = uarg->id + len - 1;
1820 is_zerocopy = uarg->zerocopy;
1821
1822 serr = SKB_EXT_ERR(skb);
1823 memset(serr, 0, sizeof(*serr));
1824 serr->ee.ee_errno = 0;
1825 serr->ee.ee_origin = SO_EE_ORIGIN_ZEROCOPY;
1826 serr->ee.ee_data = hi;
1827 serr->ee.ee_info = lo;
1828 if (!is_zerocopy)
1829 serr->ee.ee_code |= SO_EE_CODE_ZEROCOPY_COPIED;
1830
1831 q = &sk->sk_error_queue;
1832 spin_lock_irqsave(&q->lock, flags);
1833 tail = skb_peek_tail(q);
1834 if (!tail || SKB_EXT_ERR(tail)->ee.ee_origin != SO_EE_ORIGIN_ZEROCOPY ||
1835 !skb_zerocopy_notify_extend(tail, lo, len)) {
1836 __skb_queue_tail(q, skb);
1837 skb = NULL;
1838 }
1839 spin_unlock_irqrestore(&q->lock, flags);
1840
1841 sk_error_report(sk);
1842
1843release:
1844 consume_skb(skb);
1845 sock_put(sk);
1846}
1847
1848void msg_zerocopy_callback(struct sk_buff *skb, struct ubuf_info *uarg,
1849 bool success)
1850{
1851 struct ubuf_info_msgzc *uarg_zc = uarg_to_msgzc(uarg);
1852
1853 uarg_zc->zerocopy = uarg_zc->zerocopy & success;
1854
1855 if (refcount_dec_and_test(&uarg->refcnt))
1856 __msg_zerocopy_callback(uarg_zc);
1857}
1858EXPORT_SYMBOL_GPL(msg_zerocopy_callback);
1859
1860void msg_zerocopy_put_abort(struct ubuf_info *uarg, bool have_uref)
1861{
1862 struct sock *sk = skb_from_uarg(uarg_to_msgzc(uarg))->sk;
1863
1864 atomic_dec(&sk->sk_zckey);
1865 uarg_to_msgzc(uarg)->len--;
1866
1867 if (have_uref)
1868 msg_zerocopy_callback(NULL, uarg, true);
1869}
1870EXPORT_SYMBOL_GPL(msg_zerocopy_put_abort);
1871
1872int skb_zerocopy_iter_stream(struct sock *sk, struct sk_buff *skb,
1873 struct msghdr *msg, int len,
1874 struct ubuf_info *uarg)
1875{
1876 struct ubuf_info *orig_uarg = skb_zcopy(skb);
1877 int err, orig_len = skb->len;
1878
1879 /* An skb can only point to one uarg. This edge case happens when
1880 * TCP appends to an skb, but zerocopy_realloc triggered a new alloc.
1881 */
1882 if (orig_uarg && uarg != orig_uarg)
1883 return -EEXIST;
1884
1885 err = __zerocopy_sg_from_iter(msg, sk, skb, &msg->msg_iter, len);
1886 if (err == -EFAULT || (err == -EMSGSIZE && skb->len == orig_len)) {
1887 struct sock *save_sk = skb->sk;
1888
1889 /* Streams do not free skb on error. Reset to prev state. */
1890 iov_iter_revert(&msg->msg_iter, skb->len - orig_len);
1891 skb->sk = sk;
1892 ___pskb_trim(skb, orig_len);
1893 skb->sk = save_sk;
1894 return err;
1895 }
1896
1897 skb_zcopy_set(skb, uarg, NULL);
1898 return skb->len - orig_len;
1899}
1900EXPORT_SYMBOL_GPL(skb_zerocopy_iter_stream);
1901
1902void __skb_zcopy_downgrade_managed(struct sk_buff *skb)
1903{
1904 int i;
1905
1906 skb_shinfo(skb)->flags &= ~SKBFL_MANAGED_FRAG_REFS;
1907 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
1908 skb_frag_ref(skb, i);
1909}
1910EXPORT_SYMBOL_GPL(__skb_zcopy_downgrade_managed);
1911
1912static int skb_zerocopy_clone(struct sk_buff *nskb, struct sk_buff *orig,
1913 gfp_t gfp_mask)
1914{
1915 if (skb_zcopy(orig)) {
1916 if (skb_zcopy(nskb)) {
1917 /* !gfp_mask callers are verified to !skb_zcopy(nskb) */
1918 if (!gfp_mask) {
1919 WARN_ON_ONCE(1);
1920 return -ENOMEM;
1921 }
1922 if (skb_uarg(nskb) == skb_uarg(orig))
1923 return 0;
1924 if (skb_copy_ubufs(nskb, GFP_ATOMIC))
1925 return -EIO;
1926 }
1927 skb_zcopy_set(nskb, skb_uarg(orig), NULL);
1928 }
1929 return 0;
1930}
1931
1932/**
1933 * skb_copy_ubufs - copy userspace skb frags buffers to kernel
1934 * @skb: the skb to modify
1935 * @gfp_mask: allocation priority
1936 *
1937 * This must be called on skb with SKBFL_ZEROCOPY_ENABLE.
1938 * It will copy all frags into kernel and drop the reference
1939 * to userspace pages.
1940 *
1941 * If this function is called from an interrupt gfp_mask() must be
1942 * %GFP_ATOMIC.
1943 *
1944 * Returns 0 on success or a negative error code on failure
1945 * to allocate kernel memory to copy to.
1946 */
1947int skb_copy_ubufs(struct sk_buff *skb, gfp_t gfp_mask)
1948{
1949 int num_frags = skb_shinfo(skb)->nr_frags;
1950 struct page *page, *head = NULL;
1951 int i, order, psize, new_frags;
1952 u32 d_off;
1953
1954 if (skb_shared(skb) || skb_unclone(skb, gfp_mask))
1955 return -EINVAL;
1956
1957 if (!num_frags)
1958 goto release;
1959
1960 /* We might have to allocate high order pages, so compute what minimum
1961 * page order is needed.
1962 */
1963 order = 0;
1964 while ((PAGE_SIZE << order) * MAX_SKB_FRAGS < __skb_pagelen(skb))
1965 order++;
1966 psize = (PAGE_SIZE << order);
1967
1968 new_frags = (__skb_pagelen(skb) + psize - 1) >> (PAGE_SHIFT + order);
1969 for (i = 0; i < new_frags; i++) {
1970 page = alloc_pages(gfp_mask | __GFP_COMP, order);
1971 if (!page) {
1972 while (head) {
1973 struct page *next = (struct page *)page_private(head);
1974 put_page(head);
1975 head = next;
1976 }
1977 return -ENOMEM;
1978 }
1979 set_page_private(page, (unsigned long)head);
1980 head = page;
1981 }
1982
1983 page = head;
1984 d_off = 0;
1985 for (i = 0; i < num_frags; i++) {
1986 skb_frag_t *f = &skb_shinfo(skb)->frags[i];
1987 u32 p_off, p_len, copied;
1988 struct page *p;
1989 u8 *vaddr;
1990
1991 skb_frag_foreach_page(f, skb_frag_off(f), skb_frag_size(f),
1992 p, p_off, p_len, copied) {
1993 u32 copy, done = 0;
1994 vaddr = kmap_atomic(p);
1995
1996 while (done < p_len) {
1997 if (d_off == psize) {
1998 d_off = 0;
1999 page = (struct page *)page_private(page);
2000 }
2001 copy = min_t(u32, psize - d_off, p_len - done);
2002 memcpy(page_address(page) + d_off,
2003 vaddr + p_off + done, copy);
2004 done += copy;
2005 d_off += copy;
2006 }
2007 kunmap_atomic(vaddr);
2008 }
2009 }
2010
2011 /* skb frags release userspace buffers */
2012 for (i = 0; i < num_frags; i++)
2013 skb_frag_unref(skb, i);
2014
2015 /* skb frags point to kernel buffers */
2016 for (i = 0; i < new_frags - 1; i++) {
2017 __skb_fill_netmem_desc(skb, i, page_to_netmem(head), 0, psize);
2018 head = (struct page *)page_private(head);
2019 }
2020 __skb_fill_netmem_desc(skb, new_frags - 1, page_to_netmem(head), 0,
2021 d_off);
2022 skb_shinfo(skb)->nr_frags = new_frags;
2023
2024release:
2025 skb_zcopy_clear(skb, false);
2026 return 0;
2027}
2028EXPORT_SYMBOL_GPL(skb_copy_ubufs);
2029
2030/**
2031 * skb_clone - duplicate an sk_buff
2032 * @skb: buffer to clone
2033 * @gfp_mask: allocation priority
2034 *
2035 * Duplicate an &sk_buff. The new one is not owned by a socket. Both
2036 * copies share the same packet data but not structure. The new
2037 * buffer has a reference count of 1. If the allocation fails the
2038 * function returns %NULL otherwise the new buffer is returned.
2039 *
2040 * If this function is called from an interrupt gfp_mask() must be
2041 * %GFP_ATOMIC.
2042 */
2043
2044struct sk_buff *skb_clone(struct sk_buff *skb, gfp_t gfp_mask)
2045{
2046 struct sk_buff_fclones *fclones = container_of(skb,
2047 struct sk_buff_fclones,
2048 skb1);
2049 struct sk_buff *n;
2050
2051 if (skb_orphan_frags(skb, gfp_mask))
2052 return NULL;
2053
2054 if (skb->fclone == SKB_FCLONE_ORIG &&
2055 refcount_read(&fclones->fclone_ref) == 1) {
2056 n = &fclones->skb2;
2057 refcount_set(&fclones->fclone_ref, 2);
2058 n->fclone = SKB_FCLONE_CLONE;
2059 } else {
2060 if (skb_pfmemalloc(skb))
2061 gfp_mask |= __GFP_MEMALLOC;
2062
2063 n = kmem_cache_alloc(net_hotdata.skbuff_cache, gfp_mask);
2064 if (!n)
2065 return NULL;
2066
2067 n->fclone = SKB_FCLONE_UNAVAILABLE;
2068 }
2069
2070 return __skb_clone(n, skb);
2071}
2072EXPORT_SYMBOL(skb_clone);
2073
2074void skb_headers_offset_update(struct sk_buff *skb, int off)
2075{
2076 /* Only adjust this if it actually is csum_start rather than csum */
2077 if (skb->ip_summed == CHECKSUM_PARTIAL)
2078 skb->csum_start += off;
2079 /* {transport,network,mac}_header and tail are relative to skb->head */
2080 skb->transport_header += off;
2081 skb->network_header += off;
2082 if (skb_mac_header_was_set(skb))
2083 skb->mac_header += off;
2084 skb->inner_transport_header += off;
2085 skb->inner_network_header += off;
2086 skb->inner_mac_header += off;
2087}
2088EXPORT_SYMBOL(skb_headers_offset_update);
2089
2090void skb_copy_header(struct sk_buff *new, const struct sk_buff *old)
2091{
2092 __copy_skb_header(new, old);
2093
2094 skb_shinfo(new)->gso_size = skb_shinfo(old)->gso_size;
2095 skb_shinfo(new)->gso_segs = skb_shinfo(old)->gso_segs;
2096 skb_shinfo(new)->gso_type = skb_shinfo(old)->gso_type;
2097}
2098EXPORT_SYMBOL(skb_copy_header);
2099
2100static inline int skb_alloc_rx_flag(const struct sk_buff *skb)
2101{
2102 if (skb_pfmemalloc(skb))
2103 return SKB_ALLOC_RX;
2104 return 0;
2105}
2106
2107/**
2108 * skb_copy - create private copy of an sk_buff
2109 * @skb: buffer to copy
2110 * @gfp_mask: allocation priority
2111 *
2112 * Make a copy of both an &sk_buff and its data. This is used when the
2113 * caller wishes to modify the data and needs a private copy of the
2114 * data to alter. Returns %NULL on failure or the pointer to the buffer
2115 * on success. The returned buffer has a reference count of 1.
2116 *
2117 * As by-product this function converts non-linear &sk_buff to linear
2118 * one, so that &sk_buff becomes completely private and caller is allowed
2119 * to modify all the data of returned buffer. This means that this
2120 * function is not recommended for use in circumstances when only
2121 * header is going to be modified. Use pskb_copy() instead.
2122 */
2123
2124struct sk_buff *skb_copy(const struct sk_buff *skb, gfp_t gfp_mask)
2125{
2126 struct sk_buff *n;
2127 unsigned int size;
2128 int headerlen;
2129
2130 if (WARN_ON_ONCE(skb_shinfo(skb)->gso_type & SKB_GSO_FRAGLIST))
2131 return NULL;
2132
2133 headerlen = skb_headroom(skb);
2134 size = skb_end_offset(skb) + skb->data_len;
2135 n = __alloc_skb(size, gfp_mask,
2136 skb_alloc_rx_flag(skb), NUMA_NO_NODE);
2137 if (!n)
2138 return NULL;
2139
2140 /* Set the data pointer */
2141 skb_reserve(n, headerlen);
2142 /* Set the tail pointer and length */
2143 skb_put(n, skb->len);
2144
2145 BUG_ON(skb_copy_bits(skb, -headerlen, n->head, headerlen + skb->len));
2146
2147 skb_copy_header(n, skb);
2148 return n;
2149}
2150EXPORT_SYMBOL(skb_copy);
2151
2152/**
2153 * __pskb_copy_fclone - create copy of an sk_buff with private head.
2154 * @skb: buffer to copy
2155 * @headroom: headroom of new skb
2156 * @gfp_mask: allocation priority
2157 * @fclone: if true allocate the copy of the skb from the fclone
2158 * cache instead of the head cache; it is recommended to set this
2159 * to true for the cases where the copy will likely be cloned
2160 *
2161 * Make a copy of both an &sk_buff and part of its data, located
2162 * in header. Fragmented data remain shared. This is used when
2163 * the caller wishes to modify only header of &sk_buff and needs
2164 * private copy of the header to alter. Returns %NULL on failure
2165 * or the pointer to the buffer on success.
2166 * The returned buffer has a reference count of 1.
2167 */
2168
2169struct sk_buff *__pskb_copy_fclone(struct sk_buff *skb, int headroom,
2170 gfp_t gfp_mask, bool fclone)
2171{
2172 unsigned int size = skb_headlen(skb) + headroom;
2173 int flags = skb_alloc_rx_flag(skb) | (fclone ? SKB_ALLOC_FCLONE : 0);
2174 struct sk_buff *n = __alloc_skb(size, gfp_mask, flags, NUMA_NO_NODE);
2175
2176 if (!n)
2177 goto out;
2178
2179 /* Set the data pointer */
2180 skb_reserve(n, headroom);
2181 /* Set the tail pointer and length */
2182 skb_put(n, skb_headlen(skb));
2183 /* Copy the bytes */
2184 skb_copy_from_linear_data(skb, n->data, n->len);
2185
2186 n->truesize += skb->data_len;
2187 n->data_len = skb->data_len;
2188 n->len = skb->len;
2189
2190 if (skb_shinfo(skb)->nr_frags) {
2191 int i;
2192
2193 if (skb_orphan_frags(skb, gfp_mask) ||
2194 skb_zerocopy_clone(n, skb, gfp_mask)) {
2195 kfree_skb(n);
2196 n = NULL;
2197 goto out;
2198 }
2199 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
2200 skb_shinfo(n)->frags[i] = skb_shinfo(skb)->frags[i];
2201 skb_frag_ref(skb, i);
2202 }
2203 skb_shinfo(n)->nr_frags = i;
2204 }
2205
2206 if (skb_has_frag_list(skb)) {
2207 skb_shinfo(n)->frag_list = skb_shinfo(skb)->frag_list;
2208 skb_clone_fraglist(n);
2209 }
2210
2211 skb_copy_header(n, skb);
2212out:
2213 return n;
2214}
2215EXPORT_SYMBOL(__pskb_copy_fclone);
2216
2217/**
2218 * pskb_expand_head - reallocate header of &sk_buff
2219 * @skb: buffer to reallocate
2220 * @nhead: room to add at head
2221 * @ntail: room to add at tail
2222 * @gfp_mask: allocation priority
2223 *
2224 * Expands (or creates identical copy, if @nhead and @ntail are zero)
2225 * header of @skb. &sk_buff itself is not changed. &sk_buff MUST have
2226 * reference count of 1. Returns zero in the case of success or error,
2227 * if expansion failed. In the last case, &sk_buff is not changed.
2228 *
2229 * All the pointers pointing into skb header may change and must be
2230 * reloaded after call to this function.
2231 */
2232
2233int pskb_expand_head(struct sk_buff *skb, int nhead, int ntail,
2234 gfp_t gfp_mask)
2235{
2236 unsigned int osize = skb_end_offset(skb);
2237 unsigned int size = osize + nhead + ntail;
2238 long off;
2239 u8 *data;
2240 int i;
2241
2242 BUG_ON(nhead < 0);
2243
2244 BUG_ON(skb_shared(skb));
2245
2246 skb_zcopy_downgrade_managed(skb);
2247
2248 if (skb_pfmemalloc(skb))
2249 gfp_mask |= __GFP_MEMALLOC;
2250
2251 data = kmalloc_reserve(&size, gfp_mask, NUMA_NO_NODE, NULL);
2252 if (!data)
2253 goto nodata;
2254 size = SKB_WITH_OVERHEAD(size);
2255
2256 /* Copy only real data... and, alas, header. This should be
2257 * optimized for the cases when header is void.
2258 */
2259 memcpy(data + nhead, skb->head, skb_tail_pointer(skb) - skb->head);
2260
2261 memcpy((struct skb_shared_info *)(data + size),
2262 skb_shinfo(skb),
2263 offsetof(struct skb_shared_info, frags[skb_shinfo(skb)->nr_frags]));
2264
2265 /*
2266 * if shinfo is shared we must drop the old head gracefully, but if it
2267 * is not we can just drop the old head and let the existing refcount
2268 * be since all we did is relocate the values
2269 */
2270 if (skb_cloned(skb)) {
2271 if (skb_orphan_frags(skb, gfp_mask))
2272 goto nofrags;
2273 if (skb_zcopy(skb))
2274 refcount_inc(&skb_uarg(skb)->refcnt);
2275 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
2276 skb_frag_ref(skb, i);
2277
2278 if (skb_has_frag_list(skb))
2279 skb_clone_fraglist(skb);
2280
2281 skb_release_data(skb, SKB_CONSUMED, false);
2282 } else {
2283 skb_free_head(skb, false);
2284 }
2285 off = (data + nhead) - skb->head;
2286
2287 skb->head = data;
2288 skb->head_frag = 0;
2289 skb->data += off;
2290
2291 skb_set_end_offset(skb, size);
2292#ifdef NET_SKBUFF_DATA_USES_OFFSET
2293 off = nhead;
2294#endif
2295 skb->tail += off;
2296 skb_headers_offset_update(skb, nhead);
2297 skb->cloned = 0;
2298 skb->hdr_len = 0;
2299 skb->nohdr = 0;
2300 atomic_set(&skb_shinfo(skb)->dataref, 1);
2301
2302 skb_metadata_clear(skb);
2303
2304 /* It is not generally safe to change skb->truesize.
2305 * For the moment, we really care of rx path, or
2306 * when skb is orphaned (not attached to a socket).
2307 */
2308 if (!skb->sk || skb->destructor == sock_edemux)
2309 skb->truesize += size - osize;
2310
2311 return 0;
2312
2313nofrags:
2314 skb_kfree_head(data, size);
2315nodata:
2316 return -ENOMEM;
2317}
2318EXPORT_SYMBOL(pskb_expand_head);
2319
2320/* Make private copy of skb with writable head and some headroom */
2321
2322struct sk_buff *skb_realloc_headroom(struct sk_buff *skb, unsigned int headroom)
2323{
2324 struct sk_buff *skb2;
2325 int delta = headroom - skb_headroom(skb);
2326
2327 if (delta <= 0)
2328 skb2 = pskb_copy(skb, GFP_ATOMIC);
2329 else {
2330 skb2 = skb_clone(skb, GFP_ATOMIC);
2331 if (skb2 && pskb_expand_head(skb2, SKB_DATA_ALIGN(delta), 0,
2332 GFP_ATOMIC)) {
2333 kfree_skb(skb2);
2334 skb2 = NULL;
2335 }
2336 }
2337 return skb2;
2338}
2339EXPORT_SYMBOL(skb_realloc_headroom);
2340
2341/* Note: We plan to rework this in linux-6.4 */
2342int __skb_unclone_keeptruesize(struct sk_buff *skb, gfp_t pri)
2343{
2344 unsigned int saved_end_offset, saved_truesize;
2345 struct skb_shared_info *shinfo;
2346 int res;
2347
2348 saved_end_offset = skb_end_offset(skb);
2349 saved_truesize = skb->truesize;
2350
2351 res = pskb_expand_head(skb, 0, 0, pri);
2352 if (res)
2353 return res;
2354
2355 skb->truesize = saved_truesize;
2356
2357 if (likely(skb_end_offset(skb) == saved_end_offset))
2358 return 0;
2359
2360 /* We can not change skb->end if the original or new value
2361 * is SKB_SMALL_HEAD_HEADROOM, as it might break skb_kfree_head().
2362 */
2363 if (saved_end_offset == SKB_SMALL_HEAD_HEADROOM ||
2364 skb_end_offset(skb) == SKB_SMALL_HEAD_HEADROOM) {
2365 /* We think this path should not be taken.
2366 * Add a temporary trace to warn us just in case.
2367 */
2368 pr_err_once("__skb_unclone_keeptruesize() skb_end_offset() %u -> %u\n",
2369 saved_end_offset, skb_end_offset(skb));
2370 WARN_ON_ONCE(1);
2371 return 0;
2372 }
2373
2374 shinfo = skb_shinfo(skb);
2375
2376 /* We are about to change back skb->end,
2377 * we need to move skb_shinfo() to its new location.
2378 */
2379 memmove(skb->head + saved_end_offset,
2380 shinfo,
2381 offsetof(struct skb_shared_info, frags[shinfo->nr_frags]));
2382
2383 skb_set_end_offset(skb, saved_end_offset);
2384
2385 return 0;
2386}
2387
2388/**
2389 * skb_expand_head - reallocate header of &sk_buff
2390 * @skb: buffer to reallocate
2391 * @headroom: needed headroom
2392 *
2393 * Unlike skb_realloc_headroom, this one does not allocate a new skb
2394 * if possible; copies skb->sk to new skb as needed
2395 * and frees original skb in case of failures.
2396 *
2397 * It expect increased headroom and generates warning otherwise.
2398 */
2399
2400struct sk_buff *skb_expand_head(struct sk_buff *skb, unsigned int headroom)
2401{
2402 int delta = headroom - skb_headroom(skb);
2403 int osize = skb_end_offset(skb);
2404 struct sock *sk = skb->sk;
2405
2406 if (WARN_ONCE(delta <= 0,
2407 "%s is expecting an increase in the headroom", __func__))
2408 return skb;
2409
2410 delta = SKB_DATA_ALIGN(delta);
2411 /* pskb_expand_head() might crash, if skb is shared. */
2412 if (skb_shared(skb) || !is_skb_wmem(skb)) {
2413 struct sk_buff *nskb = skb_clone(skb, GFP_ATOMIC);
2414
2415 if (unlikely(!nskb))
2416 goto fail;
2417
2418 if (sk)
2419 skb_set_owner_w(nskb, sk);
2420 consume_skb(skb);
2421 skb = nskb;
2422 }
2423 if (pskb_expand_head(skb, delta, 0, GFP_ATOMIC))
2424 goto fail;
2425
2426 if (sk && is_skb_wmem(skb)) {
2427 delta = skb_end_offset(skb) - osize;
2428 refcount_add(delta, &sk->sk_wmem_alloc);
2429 skb->truesize += delta;
2430 }
2431 return skb;
2432
2433fail:
2434 kfree_skb(skb);
2435 return NULL;
2436}
2437EXPORT_SYMBOL(skb_expand_head);
2438
2439/**
2440 * skb_copy_expand - copy and expand sk_buff
2441 * @skb: buffer to copy
2442 * @newheadroom: new free bytes at head
2443 * @newtailroom: new free bytes at tail
2444 * @gfp_mask: allocation priority
2445 *
2446 * Make a copy of both an &sk_buff and its data and while doing so
2447 * allocate additional space.
2448 *
2449 * This is used when the caller wishes to modify the data and needs a
2450 * private copy of the data to alter as well as more space for new fields.
2451 * Returns %NULL on failure or the pointer to the buffer
2452 * on success. The returned buffer has a reference count of 1.
2453 *
2454 * You must pass %GFP_ATOMIC as the allocation priority if this function
2455 * is called from an interrupt.
2456 */
2457struct sk_buff *skb_copy_expand(const struct sk_buff *skb,
2458 int newheadroom, int newtailroom,
2459 gfp_t gfp_mask)
2460{
2461 /*
2462 * Allocate the copy buffer
2463 */
2464 int head_copy_len, head_copy_off;
2465 struct sk_buff *n;
2466 int oldheadroom;
2467
2468 if (WARN_ON_ONCE(skb_shinfo(skb)->gso_type & SKB_GSO_FRAGLIST))
2469 return NULL;
2470
2471 oldheadroom = skb_headroom(skb);
2472 n = __alloc_skb(newheadroom + skb->len + newtailroom,
2473 gfp_mask, skb_alloc_rx_flag(skb),
2474 NUMA_NO_NODE);
2475 if (!n)
2476 return NULL;
2477
2478 skb_reserve(n, newheadroom);
2479
2480 /* Set the tail pointer and length */
2481 skb_put(n, skb->len);
2482
2483 head_copy_len = oldheadroom;
2484 head_copy_off = 0;
2485 if (newheadroom <= head_copy_len)
2486 head_copy_len = newheadroom;
2487 else
2488 head_copy_off = newheadroom - head_copy_len;
2489
2490 /* Copy the linear header and data. */
2491 BUG_ON(skb_copy_bits(skb, -head_copy_len, n->head + head_copy_off,
2492 skb->len + head_copy_len));
2493
2494 skb_copy_header(n, skb);
2495
2496 skb_headers_offset_update(n, newheadroom - oldheadroom);
2497
2498 return n;
2499}
2500EXPORT_SYMBOL(skb_copy_expand);
2501
2502/**
2503 * __skb_pad - zero pad the tail of an skb
2504 * @skb: buffer to pad
2505 * @pad: space to pad
2506 * @free_on_error: free buffer on error
2507 *
2508 * Ensure that a buffer is followed by a padding area that is zero
2509 * filled. Used by network drivers which may DMA or transfer data
2510 * beyond the buffer end onto the wire.
2511 *
2512 * May return error in out of memory cases. The skb is freed on error
2513 * if @free_on_error is true.
2514 */
2515
2516int __skb_pad(struct sk_buff *skb, int pad, bool free_on_error)
2517{
2518 int err;
2519 int ntail;
2520
2521 /* If the skbuff is non linear tailroom is always zero.. */
2522 if (!skb_cloned(skb) && skb_tailroom(skb) >= pad) {
2523 memset(skb->data+skb->len, 0, pad);
2524 return 0;
2525 }
2526
2527 ntail = skb->data_len + pad - (skb->end - skb->tail);
2528 if (likely(skb_cloned(skb) || ntail > 0)) {
2529 err = pskb_expand_head(skb, 0, ntail, GFP_ATOMIC);
2530 if (unlikely(err))
2531 goto free_skb;
2532 }
2533
2534 /* FIXME: The use of this function with non-linear skb's really needs
2535 * to be audited.
2536 */
2537 err = skb_linearize(skb);
2538 if (unlikely(err))
2539 goto free_skb;
2540
2541 memset(skb->data + skb->len, 0, pad);
2542 return 0;
2543
2544free_skb:
2545 if (free_on_error)
2546 kfree_skb(skb);
2547 return err;
2548}
2549EXPORT_SYMBOL(__skb_pad);
2550
2551/**
2552 * pskb_put - add data to the tail of a potentially fragmented buffer
2553 * @skb: start of the buffer to use
2554 * @tail: tail fragment of the buffer to use
2555 * @len: amount of data to add
2556 *
2557 * This function extends the used data area of the potentially
2558 * fragmented buffer. @tail must be the last fragment of @skb -- or
2559 * @skb itself. If this would exceed the total buffer size the kernel
2560 * will panic. A pointer to the first byte of the extra data is
2561 * returned.
2562 */
2563
2564void *pskb_put(struct sk_buff *skb, struct sk_buff *tail, int len)
2565{
2566 if (tail != skb) {
2567 skb->data_len += len;
2568 skb->len += len;
2569 }
2570 return skb_put(tail, len);
2571}
2572EXPORT_SYMBOL_GPL(pskb_put);
2573
2574/**
2575 * skb_put - add data to a buffer
2576 * @skb: buffer to use
2577 * @len: amount of data to add
2578 *
2579 * This function extends the used data area of the buffer. If this would
2580 * exceed the total buffer size the kernel will panic. A pointer to the
2581 * first byte of the extra data is returned.
2582 */
2583void *skb_put(struct sk_buff *skb, unsigned int len)
2584{
2585 void *tmp = skb_tail_pointer(skb);
2586 SKB_LINEAR_ASSERT(skb);
2587 skb->tail += len;
2588 skb->len += len;
2589 if (unlikely(skb->tail > skb->end))
2590 skb_over_panic(skb, len, __builtin_return_address(0));
2591 return tmp;
2592}
2593EXPORT_SYMBOL(skb_put);
2594
2595/**
2596 * skb_push - add data to the start of a buffer
2597 * @skb: buffer to use
2598 * @len: amount of data to add
2599 *
2600 * This function extends the used data area of the buffer at the buffer
2601 * start. If this would exceed the total buffer headroom the kernel will
2602 * panic. A pointer to the first byte of the extra data is returned.
2603 */
2604void *skb_push(struct sk_buff *skb, unsigned int len)
2605{
2606 skb->data -= len;
2607 skb->len += len;
2608 if (unlikely(skb->data < skb->head))
2609 skb_under_panic(skb, len, __builtin_return_address(0));
2610 return skb->data;
2611}
2612EXPORT_SYMBOL(skb_push);
2613
2614/**
2615 * skb_pull - remove data from the start of a buffer
2616 * @skb: buffer to use
2617 * @len: amount of data to remove
2618 *
2619 * This function removes data from the start of a buffer, returning
2620 * the memory to the headroom. A pointer to the next data in the buffer
2621 * is returned. Once the data has been pulled future pushes will overwrite
2622 * the old data.
2623 */
2624void *skb_pull(struct sk_buff *skb, unsigned int len)
2625{
2626 return skb_pull_inline(skb, len);
2627}
2628EXPORT_SYMBOL(skb_pull);
2629
2630/**
2631 * skb_pull_data - remove data from the start of a buffer returning its
2632 * original position.
2633 * @skb: buffer to use
2634 * @len: amount of data to remove
2635 *
2636 * This function removes data from the start of a buffer, returning
2637 * the memory to the headroom. A pointer to the original data in the buffer
2638 * is returned after checking if there is enough data to pull. Once the
2639 * data has been pulled future pushes will overwrite the old data.
2640 */
2641void *skb_pull_data(struct sk_buff *skb, size_t len)
2642{
2643 void *data = skb->data;
2644
2645 if (skb->len < len)
2646 return NULL;
2647
2648 skb_pull(skb, len);
2649
2650 return data;
2651}
2652EXPORT_SYMBOL(skb_pull_data);
2653
2654/**
2655 * skb_trim - remove end from a buffer
2656 * @skb: buffer to alter
2657 * @len: new length
2658 *
2659 * Cut the length of a buffer down by removing data from the tail. If
2660 * the buffer is already under the length specified it is not modified.
2661 * The skb must be linear.
2662 */
2663void skb_trim(struct sk_buff *skb, unsigned int len)
2664{
2665 if (skb->len > len)
2666 __skb_trim(skb, len);
2667}
2668EXPORT_SYMBOL(skb_trim);
2669
2670/* Trims skb to length len. It can change skb pointers.
2671 */
2672
2673int ___pskb_trim(struct sk_buff *skb, unsigned int len)
2674{
2675 struct sk_buff **fragp;
2676 struct sk_buff *frag;
2677 int offset = skb_headlen(skb);
2678 int nfrags = skb_shinfo(skb)->nr_frags;
2679 int i;
2680 int err;
2681
2682 if (skb_cloned(skb) &&
2683 unlikely((err = pskb_expand_head(skb, 0, 0, GFP_ATOMIC))))
2684 return err;
2685
2686 i = 0;
2687 if (offset >= len)
2688 goto drop_pages;
2689
2690 for (; i < nfrags; i++) {
2691 int end = offset + skb_frag_size(&skb_shinfo(skb)->frags[i]);
2692
2693 if (end < len) {
2694 offset = end;
2695 continue;
2696 }
2697
2698 skb_frag_size_set(&skb_shinfo(skb)->frags[i++], len - offset);
2699
2700drop_pages:
2701 skb_shinfo(skb)->nr_frags = i;
2702
2703 for (; i < nfrags; i++)
2704 skb_frag_unref(skb, i);
2705
2706 if (skb_has_frag_list(skb))
2707 skb_drop_fraglist(skb);
2708 goto done;
2709 }
2710
2711 for (fragp = &skb_shinfo(skb)->frag_list; (frag = *fragp);
2712 fragp = &frag->next) {
2713 int end = offset + frag->len;
2714
2715 if (skb_shared(frag)) {
2716 struct sk_buff *nfrag;
2717
2718 nfrag = skb_clone(frag, GFP_ATOMIC);
2719 if (unlikely(!nfrag))
2720 return -ENOMEM;
2721
2722 nfrag->next = frag->next;
2723 consume_skb(frag);
2724 frag = nfrag;
2725 *fragp = frag;
2726 }
2727
2728 if (end < len) {
2729 offset = end;
2730 continue;
2731 }
2732
2733 if (end > len &&
2734 unlikely((err = pskb_trim(frag, len - offset))))
2735 return err;
2736
2737 if (frag->next)
2738 skb_drop_list(&frag->next);
2739 break;
2740 }
2741
2742done:
2743 if (len > skb_headlen(skb)) {
2744 skb->data_len -= skb->len - len;
2745 skb->len = len;
2746 } else {
2747 skb->len = len;
2748 skb->data_len = 0;
2749 skb_set_tail_pointer(skb, len);
2750 }
2751
2752 if (!skb->sk || skb->destructor == sock_edemux)
2753 skb_condense(skb);
2754 return 0;
2755}
2756EXPORT_SYMBOL(___pskb_trim);
2757
2758/* Note : use pskb_trim_rcsum() instead of calling this directly
2759 */
2760int pskb_trim_rcsum_slow(struct sk_buff *skb, unsigned int len)
2761{
2762 if (skb->ip_summed == CHECKSUM_COMPLETE) {
2763 int delta = skb->len - len;
2764
2765 skb->csum = csum_block_sub(skb->csum,
2766 skb_checksum(skb, len, delta, 0),
2767 len);
2768 } else if (skb->ip_summed == CHECKSUM_PARTIAL) {
2769 int hdlen = (len > skb_headlen(skb)) ? skb_headlen(skb) : len;
2770 int offset = skb_checksum_start_offset(skb) + skb->csum_offset;
2771
2772 if (offset + sizeof(__sum16) > hdlen)
2773 return -EINVAL;
2774 }
2775 return __pskb_trim(skb, len);
2776}
2777EXPORT_SYMBOL(pskb_trim_rcsum_slow);
2778
2779/**
2780 * __pskb_pull_tail - advance tail of skb header
2781 * @skb: buffer to reallocate
2782 * @delta: number of bytes to advance tail
2783 *
2784 * The function makes a sense only on a fragmented &sk_buff,
2785 * it expands header moving its tail forward and copying necessary
2786 * data from fragmented part.
2787 *
2788 * &sk_buff MUST have reference count of 1.
2789 *
2790 * Returns %NULL (and &sk_buff does not change) if pull failed
2791 * or value of new tail of skb in the case of success.
2792 *
2793 * All the pointers pointing into skb header may change and must be
2794 * reloaded after call to this function.
2795 */
2796
2797/* Moves tail of skb head forward, copying data from fragmented part,
2798 * when it is necessary.
2799 * 1. It may fail due to malloc failure.
2800 * 2. It may change skb pointers.
2801 *
2802 * It is pretty complicated. Luckily, it is called only in exceptional cases.
2803 */
2804void *__pskb_pull_tail(struct sk_buff *skb, int delta)
2805{
2806 /* If skb has not enough free space at tail, get new one
2807 * plus 128 bytes for future expansions. If we have enough
2808 * room at tail, reallocate without expansion only if skb is cloned.
2809 */
2810 int i, k, eat = (skb->tail + delta) - skb->end;
2811
2812 if (eat > 0 || skb_cloned(skb)) {
2813 if (pskb_expand_head(skb, 0, eat > 0 ? eat + 128 : 0,
2814 GFP_ATOMIC))
2815 return NULL;
2816 }
2817
2818 BUG_ON(skb_copy_bits(skb, skb_headlen(skb),
2819 skb_tail_pointer(skb), delta));
2820
2821 /* Optimization: no fragments, no reasons to preestimate
2822 * size of pulled pages. Superb.
2823 */
2824 if (!skb_has_frag_list(skb))
2825 goto pull_pages;
2826
2827 /* Estimate size of pulled pages. */
2828 eat = delta;
2829 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
2830 int size = skb_frag_size(&skb_shinfo(skb)->frags[i]);
2831
2832 if (size >= eat)
2833 goto pull_pages;
2834 eat -= size;
2835 }
2836
2837 /* If we need update frag list, we are in troubles.
2838 * Certainly, it is possible to add an offset to skb data,
2839 * but taking into account that pulling is expected to
2840 * be very rare operation, it is worth to fight against
2841 * further bloating skb head and crucify ourselves here instead.
2842 * Pure masohism, indeed. 8)8)
2843 */
2844 if (eat) {
2845 struct sk_buff *list = skb_shinfo(skb)->frag_list;
2846 struct sk_buff *clone = NULL;
2847 struct sk_buff *insp = NULL;
2848
2849 do {
2850 if (list->len <= eat) {
2851 /* Eaten as whole. */
2852 eat -= list->len;
2853 list = list->next;
2854 insp = list;
2855 } else {
2856 /* Eaten partially. */
2857 if (skb_is_gso(skb) && !list->head_frag &&
2858 skb_headlen(list))
2859 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
2860
2861 if (skb_shared(list)) {
2862 /* Sucks! We need to fork list. :-( */
2863 clone = skb_clone(list, GFP_ATOMIC);
2864 if (!clone)
2865 return NULL;
2866 insp = list->next;
2867 list = clone;
2868 } else {
2869 /* This may be pulled without
2870 * problems. */
2871 insp = list;
2872 }
2873 if (!pskb_pull(list, eat)) {
2874 kfree_skb(clone);
2875 return NULL;
2876 }
2877 break;
2878 }
2879 } while (eat);
2880
2881 /* Free pulled out fragments. */
2882 while ((list = skb_shinfo(skb)->frag_list) != insp) {
2883 skb_shinfo(skb)->frag_list = list->next;
2884 consume_skb(list);
2885 }
2886 /* And insert new clone at head. */
2887 if (clone) {
2888 clone->next = list;
2889 skb_shinfo(skb)->frag_list = clone;
2890 }
2891 }
2892 /* Success! Now we may commit changes to skb data. */
2893
2894pull_pages:
2895 eat = delta;
2896 k = 0;
2897 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
2898 int size = skb_frag_size(&skb_shinfo(skb)->frags[i]);
2899
2900 if (size <= eat) {
2901 skb_frag_unref(skb, i);
2902 eat -= size;
2903 } else {
2904 skb_frag_t *frag = &skb_shinfo(skb)->frags[k];
2905
2906 *frag = skb_shinfo(skb)->frags[i];
2907 if (eat) {
2908 skb_frag_off_add(frag, eat);
2909 skb_frag_size_sub(frag, eat);
2910 if (!i)
2911 goto end;
2912 eat = 0;
2913 }
2914 k++;
2915 }
2916 }
2917 skb_shinfo(skb)->nr_frags = k;
2918
2919end:
2920 skb->tail += delta;
2921 skb->data_len -= delta;
2922
2923 if (!skb->data_len)
2924 skb_zcopy_clear(skb, false);
2925
2926 return skb_tail_pointer(skb);
2927}
2928EXPORT_SYMBOL(__pskb_pull_tail);
2929
2930/**
2931 * skb_copy_bits - copy bits from skb to kernel buffer
2932 * @skb: source skb
2933 * @offset: offset in source
2934 * @to: destination buffer
2935 * @len: number of bytes to copy
2936 *
2937 * Copy the specified number of bytes from the source skb to the
2938 * destination buffer.
2939 *
2940 * CAUTION ! :
2941 * If its prototype is ever changed,
2942 * check arch/{*}/net/{*}.S files,
2943 * since it is called from BPF assembly code.
2944 */
2945int skb_copy_bits(const struct sk_buff *skb, int offset, void *to, int len)
2946{
2947 int start = skb_headlen(skb);
2948 struct sk_buff *frag_iter;
2949 int i, copy;
2950
2951 if (offset > (int)skb->len - len)
2952 goto fault;
2953
2954 /* Copy header. */
2955 if ((copy = start - offset) > 0) {
2956 if (copy > len)
2957 copy = len;
2958 skb_copy_from_linear_data_offset(skb, offset, to, copy);
2959 if ((len -= copy) == 0)
2960 return 0;
2961 offset += copy;
2962 to += copy;
2963 }
2964
2965 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
2966 int end;
2967 skb_frag_t *f = &skb_shinfo(skb)->frags[i];
2968
2969 WARN_ON(start > offset + len);
2970
2971 end = start + skb_frag_size(f);
2972 if ((copy = end - offset) > 0) {
2973 u32 p_off, p_len, copied;
2974 struct page *p;
2975 u8 *vaddr;
2976
2977 if (copy > len)
2978 copy = len;
2979
2980 skb_frag_foreach_page(f,
2981 skb_frag_off(f) + offset - start,
2982 copy, p, p_off, p_len, copied) {
2983 vaddr = kmap_atomic(p);
2984 memcpy(to + copied, vaddr + p_off, p_len);
2985 kunmap_atomic(vaddr);
2986 }
2987
2988 if ((len -= copy) == 0)
2989 return 0;
2990 offset += copy;
2991 to += copy;
2992 }
2993 start = end;
2994 }
2995
2996 skb_walk_frags(skb, frag_iter) {
2997 int end;
2998
2999 WARN_ON(start > offset + len);
3000
3001 end = start + frag_iter->len;
3002 if ((copy = end - offset) > 0) {
3003 if (copy > len)
3004 copy = len;
3005 if (skb_copy_bits(frag_iter, offset - start, to, copy))
3006 goto fault;
3007 if ((len -= copy) == 0)
3008 return 0;
3009 offset += copy;
3010 to += copy;
3011 }
3012 start = end;
3013 }
3014
3015 if (!len)
3016 return 0;
3017
3018fault:
3019 return -EFAULT;
3020}
3021EXPORT_SYMBOL(skb_copy_bits);
3022
3023/*
3024 * Callback from splice_to_pipe(), if we need to release some pages
3025 * at the end of the spd in case we error'ed out in filling the pipe.
3026 */
3027static void sock_spd_release(struct splice_pipe_desc *spd, unsigned int i)
3028{
3029 put_page(spd->pages[i]);
3030}
3031
3032static struct page *linear_to_page(struct page *page, unsigned int *len,
3033 unsigned int *offset,
3034 struct sock *sk)
3035{
3036 struct page_frag *pfrag = sk_page_frag(sk);
3037
3038 if (!sk_page_frag_refill(sk, pfrag))
3039 return NULL;
3040
3041 *len = min_t(unsigned int, *len, pfrag->size - pfrag->offset);
3042
3043 memcpy(page_address(pfrag->page) + pfrag->offset,
3044 page_address(page) + *offset, *len);
3045 *offset = pfrag->offset;
3046 pfrag->offset += *len;
3047
3048 return pfrag->page;
3049}
3050
3051static bool spd_can_coalesce(const struct splice_pipe_desc *spd,
3052 struct page *page,
3053 unsigned int offset)
3054{
3055 return spd->nr_pages &&
3056 spd->pages[spd->nr_pages - 1] == page &&
3057 (spd->partial[spd->nr_pages - 1].offset +
3058 spd->partial[spd->nr_pages - 1].len == offset);
3059}
3060
3061/*
3062 * Fill page/offset/length into spd, if it can hold more pages.
3063 */
3064static bool spd_fill_page(struct splice_pipe_desc *spd,
3065 struct pipe_inode_info *pipe, struct page *page,
3066 unsigned int *len, unsigned int offset,
3067 bool linear,
3068 struct sock *sk)
3069{
3070 if (unlikely(spd->nr_pages == MAX_SKB_FRAGS))
3071 return true;
3072
3073 if (linear) {
3074 page = linear_to_page(page, len, &offset, sk);
3075 if (!page)
3076 return true;
3077 }
3078 if (spd_can_coalesce(spd, page, offset)) {
3079 spd->partial[spd->nr_pages - 1].len += *len;
3080 return false;
3081 }
3082 get_page(page);
3083 spd->pages[spd->nr_pages] = page;
3084 spd->partial[spd->nr_pages].len = *len;
3085 spd->partial[spd->nr_pages].offset = offset;
3086 spd->nr_pages++;
3087
3088 return false;
3089}
3090
3091static bool __splice_segment(struct page *page, unsigned int poff,
3092 unsigned int plen, unsigned int *off,
3093 unsigned int *len,
3094 struct splice_pipe_desc *spd, bool linear,
3095 struct sock *sk,
3096 struct pipe_inode_info *pipe)
3097{
3098 if (!*len)
3099 return true;
3100
3101 /* skip this segment if already processed */
3102 if (*off >= plen) {
3103 *off -= plen;
3104 return false;
3105 }
3106
3107 /* ignore any bits we already processed */
3108 poff += *off;
3109 plen -= *off;
3110 *off = 0;
3111
3112 do {
3113 unsigned int flen = min(*len, plen);
3114
3115 if (spd_fill_page(spd, pipe, page, &flen, poff,
3116 linear, sk))
3117 return true;
3118 poff += flen;
3119 plen -= flen;
3120 *len -= flen;
3121 } while (*len && plen);
3122
3123 return false;
3124}
3125
3126/*
3127 * Map linear and fragment data from the skb to spd. It reports true if the
3128 * pipe is full or if we already spliced the requested length.
3129 */
3130static bool __skb_splice_bits(struct sk_buff *skb, struct pipe_inode_info *pipe,
3131 unsigned int *offset, unsigned int *len,
3132 struct splice_pipe_desc *spd, struct sock *sk)
3133{
3134 int seg;
3135 struct sk_buff *iter;
3136
3137 /* map the linear part :
3138 * If skb->head_frag is set, this 'linear' part is backed by a
3139 * fragment, and if the head is not shared with any clones then
3140 * we can avoid a copy since we own the head portion of this page.
3141 */
3142 if (__splice_segment(virt_to_page(skb->data),
3143 (unsigned long) skb->data & (PAGE_SIZE - 1),
3144 skb_headlen(skb),
3145 offset, len, spd,
3146 skb_head_is_locked(skb),
3147 sk, pipe))
3148 return true;
3149
3150 /*
3151 * then map the fragments
3152 */
3153 for (seg = 0; seg < skb_shinfo(skb)->nr_frags; seg++) {
3154 const skb_frag_t *f = &skb_shinfo(skb)->frags[seg];
3155
3156 if (__splice_segment(skb_frag_page(f),
3157 skb_frag_off(f), skb_frag_size(f),
3158 offset, len, spd, false, sk, pipe))
3159 return true;
3160 }
3161
3162 skb_walk_frags(skb, iter) {
3163 if (*offset >= iter->len) {
3164 *offset -= iter->len;
3165 continue;
3166 }
3167 /* __skb_splice_bits() only fails if the output has no room
3168 * left, so no point in going over the frag_list for the error
3169 * case.
3170 */
3171 if (__skb_splice_bits(iter, pipe, offset, len, spd, sk))
3172 return true;
3173 }
3174
3175 return false;
3176}
3177
3178/*
3179 * Map data from the skb to a pipe. Should handle both the linear part,
3180 * the fragments, and the frag list.
3181 */
3182int skb_splice_bits(struct sk_buff *skb, struct sock *sk, unsigned int offset,
3183 struct pipe_inode_info *pipe, unsigned int tlen,
3184 unsigned int flags)
3185{
3186 struct partial_page partial[MAX_SKB_FRAGS];
3187 struct page *pages[MAX_SKB_FRAGS];
3188 struct splice_pipe_desc spd = {
3189 .pages = pages,
3190 .partial = partial,
3191 .nr_pages_max = MAX_SKB_FRAGS,
3192 .ops = &nosteal_pipe_buf_ops,
3193 .spd_release = sock_spd_release,
3194 };
3195 int ret = 0;
3196
3197 __skb_splice_bits(skb, pipe, &offset, &tlen, &spd, sk);
3198
3199 if (spd.nr_pages)
3200 ret = splice_to_pipe(pipe, &spd);
3201
3202 return ret;
3203}
3204EXPORT_SYMBOL_GPL(skb_splice_bits);
3205
3206static int sendmsg_locked(struct sock *sk, struct msghdr *msg)
3207{
3208 struct socket *sock = sk->sk_socket;
3209 size_t size = msg_data_left(msg);
3210
3211 if (!sock)
3212 return -EINVAL;
3213
3214 if (!sock->ops->sendmsg_locked)
3215 return sock_no_sendmsg_locked(sk, msg, size);
3216
3217 return sock->ops->sendmsg_locked(sk, msg, size);
3218}
3219
3220static int sendmsg_unlocked(struct sock *sk, struct msghdr *msg)
3221{
3222 struct socket *sock = sk->sk_socket;
3223
3224 if (!sock)
3225 return -EINVAL;
3226 return sock_sendmsg(sock, msg);
3227}
3228
3229typedef int (*sendmsg_func)(struct sock *sk, struct msghdr *msg);
3230static int __skb_send_sock(struct sock *sk, struct sk_buff *skb, int offset,
3231 int len, sendmsg_func sendmsg)
3232{
3233 unsigned int orig_len = len;
3234 struct sk_buff *head = skb;
3235 unsigned short fragidx;
3236 int slen, ret;
3237
3238do_frag_list:
3239
3240 /* Deal with head data */
3241 while (offset < skb_headlen(skb) && len) {
3242 struct kvec kv;
3243 struct msghdr msg;
3244
3245 slen = min_t(int, len, skb_headlen(skb) - offset);
3246 kv.iov_base = skb->data + offset;
3247 kv.iov_len = slen;
3248 memset(&msg, 0, sizeof(msg));
3249 msg.msg_flags = MSG_DONTWAIT;
3250
3251 iov_iter_kvec(&msg.msg_iter, ITER_SOURCE, &kv, 1, slen);
3252 ret = INDIRECT_CALL_2(sendmsg, sendmsg_locked,
3253 sendmsg_unlocked, sk, &msg);
3254 if (ret <= 0)
3255 goto error;
3256
3257 offset += ret;
3258 len -= ret;
3259 }
3260
3261 /* All the data was skb head? */
3262 if (!len)
3263 goto out;
3264
3265 /* Make offset relative to start of frags */
3266 offset -= skb_headlen(skb);
3267
3268 /* Find where we are in frag list */
3269 for (fragidx = 0; fragidx < skb_shinfo(skb)->nr_frags; fragidx++) {
3270 skb_frag_t *frag = &skb_shinfo(skb)->frags[fragidx];
3271
3272 if (offset < skb_frag_size(frag))
3273 break;
3274
3275 offset -= skb_frag_size(frag);
3276 }
3277
3278 for (; len && fragidx < skb_shinfo(skb)->nr_frags; fragidx++) {
3279 skb_frag_t *frag = &skb_shinfo(skb)->frags[fragidx];
3280
3281 slen = min_t(size_t, len, skb_frag_size(frag) - offset);
3282
3283 while (slen) {
3284 struct bio_vec bvec;
3285 struct msghdr msg = {
3286 .msg_flags = MSG_SPLICE_PAGES | MSG_DONTWAIT,
3287 };
3288
3289 bvec_set_page(&bvec, skb_frag_page(frag), slen,
3290 skb_frag_off(frag) + offset);
3291 iov_iter_bvec(&msg.msg_iter, ITER_SOURCE, &bvec, 1,
3292 slen);
3293
3294 ret = INDIRECT_CALL_2(sendmsg, sendmsg_locked,
3295 sendmsg_unlocked, sk, &msg);
3296 if (ret <= 0)
3297 goto error;
3298
3299 len -= ret;
3300 offset += ret;
3301 slen -= ret;
3302 }
3303
3304 offset = 0;
3305 }
3306
3307 if (len) {
3308 /* Process any frag lists */
3309
3310 if (skb == head) {
3311 if (skb_has_frag_list(skb)) {
3312 skb = skb_shinfo(skb)->frag_list;
3313 goto do_frag_list;
3314 }
3315 } else if (skb->next) {
3316 skb = skb->next;
3317 goto do_frag_list;
3318 }
3319 }
3320
3321out:
3322 return orig_len - len;
3323
3324error:
3325 return orig_len == len ? ret : orig_len - len;
3326}
3327
3328/* Send skb data on a socket. Socket must be locked. */
3329int skb_send_sock_locked(struct sock *sk, struct sk_buff *skb, int offset,
3330 int len)
3331{
3332 return __skb_send_sock(sk, skb, offset, len, sendmsg_locked);
3333}
3334EXPORT_SYMBOL_GPL(skb_send_sock_locked);
3335
3336/* Send skb data on a socket. Socket must be unlocked. */
3337int skb_send_sock(struct sock *sk, struct sk_buff *skb, int offset, int len)
3338{
3339 return __skb_send_sock(sk, skb, offset, len, sendmsg_unlocked);
3340}
3341
3342/**
3343 * skb_store_bits - store bits from kernel buffer to skb
3344 * @skb: destination buffer
3345 * @offset: offset in destination
3346 * @from: source buffer
3347 * @len: number of bytes to copy
3348 *
3349 * Copy the specified number of bytes from the source buffer to the
3350 * destination skb. This function handles all the messy bits of
3351 * traversing fragment lists and such.
3352 */
3353
3354int skb_store_bits(struct sk_buff *skb, int offset, const void *from, int len)
3355{
3356 int start = skb_headlen(skb);
3357 struct sk_buff *frag_iter;
3358 int i, copy;
3359
3360 if (offset > (int)skb->len - len)
3361 goto fault;
3362
3363 if ((copy = start - offset) > 0) {
3364 if (copy > len)
3365 copy = len;
3366 skb_copy_to_linear_data_offset(skb, offset, from, copy);
3367 if ((len -= copy) == 0)
3368 return 0;
3369 offset += copy;
3370 from += copy;
3371 }
3372
3373 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
3374 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
3375 int end;
3376
3377 WARN_ON(start > offset + len);
3378
3379 end = start + skb_frag_size(frag);
3380 if ((copy = end - offset) > 0) {
3381 u32 p_off, p_len, copied;
3382 struct page *p;
3383 u8 *vaddr;
3384
3385 if (copy > len)
3386 copy = len;
3387
3388 skb_frag_foreach_page(frag,
3389 skb_frag_off(frag) + offset - start,
3390 copy, p, p_off, p_len, copied) {
3391 vaddr = kmap_atomic(p);
3392 memcpy(vaddr + p_off, from + copied, p_len);
3393 kunmap_atomic(vaddr);
3394 }
3395
3396 if ((len -= copy) == 0)
3397 return 0;
3398 offset += copy;
3399 from += copy;
3400 }
3401 start = end;
3402 }
3403
3404 skb_walk_frags(skb, frag_iter) {
3405 int end;
3406
3407 WARN_ON(start > offset + len);
3408
3409 end = start + frag_iter->len;
3410 if ((copy = end - offset) > 0) {
3411 if (copy > len)
3412 copy = len;
3413 if (skb_store_bits(frag_iter, offset - start,
3414 from, copy))
3415 goto fault;
3416 if ((len -= copy) == 0)
3417 return 0;
3418 offset += copy;
3419 from += copy;
3420 }
3421 start = end;
3422 }
3423 if (!len)
3424 return 0;
3425
3426fault:
3427 return -EFAULT;
3428}
3429EXPORT_SYMBOL(skb_store_bits);
3430
3431/* Checksum skb data. */
3432__wsum __skb_checksum(const struct sk_buff *skb, int offset, int len,
3433 __wsum csum, const struct skb_checksum_ops *ops)
3434{
3435 int start = skb_headlen(skb);
3436 int i, copy = start - offset;
3437 struct sk_buff *frag_iter;
3438 int pos = 0;
3439
3440 /* Checksum header. */
3441 if (copy > 0) {
3442 if (copy > len)
3443 copy = len;
3444 csum = INDIRECT_CALL_1(ops->update, csum_partial_ext,
3445 skb->data + offset, copy, csum);
3446 if ((len -= copy) == 0)
3447 return csum;
3448 offset += copy;
3449 pos = copy;
3450 }
3451
3452 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
3453 int end;
3454 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
3455
3456 WARN_ON(start > offset + len);
3457
3458 end = start + skb_frag_size(frag);
3459 if ((copy = end - offset) > 0) {
3460 u32 p_off, p_len, copied;
3461 struct page *p;
3462 __wsum csum2;
3463 u8 *vaddr;
3464
3465 if (copy > len)
3466 copy = len;
3467
3468 skb_frag_foreach_page(frag,
3469 skb_frag_off(frag) + offset - start,
3470 copy, p, p_off, p_len, copied) {
3471 vaddr = kmap_atomic(p);
3472 csum2 = INDIRECT_CALL_1(ops->update,
3473 csum_partial_ext,
3474 vaddr + p_off, p_len, 0);
3475 kunmap_atomic(vaddr);
3476 csum = INDIRECT_CALL_1(ops->combine,
3477 csum_block_add_ext, csum,
3478 csum2, pos, p_len);
3479 pos += p_len;
3480 }
3481
3482 if (!(len -= copy))
3483 return csum;
3484 offset += copy;
3485 }
3486 start = end;
3487 }
3488
3489 skb_walk_frags(skb, frag_iter) {
3490 int end;
3491
3492 WARN_ON(start > offset + len);
3493
3494 end = start + frag_iter->len;
3495 if ((copy = end - offset) > 0) {
3496 __wsum csum2;
3497 if (copy > len)
3498 copy = len;
3499 csum2 = __skb_checksum(frag_iter, offset - start,
3500 copy, 0, ops);
3501 csum = INDIRECT_CALL_1(ops->combine, csum_block_add_ext,
3502 csum, csum2, pos, copy);
3503 if ((len -= copy) == 0)
3504 return csum;
3505 offset += copy;
3506 pos += copy;
3507 }
3508 start = end;
3509 }
3510 BUG_ON(len);
3511
3512 return csum;
3513}
3514EXPORT_SYMBOL(__skb_checksum);
3515
3516__wsum skb_checksum(const struct sk_buff *skb, int offset,
3517 int len, __wsum csum)
3518{
3519 const struct skb_checksum_ops ops = {
3520 .update = csum_partial_ext,
3521 .combine = csum_block_add_ext,
3522 };
3523
3524 return __skb_checksum(skb, offset, len, csum, &ops);
3525}
3526EXPORT_SYMBOL(skb_checksum);
3527
3528/* Both of above in one bottle. */
3529
3530__wsum skb_copy_and_csum_bits(const struct sk_buff *skb, int offset,
3531 u8 *to, int len)
3532{
3533 int start = skb_headlen(skb);
3534 int i, copy = start - offset;
3535 struct sk_buff *frag_iter;
3536 int pos = 0;
3537 __wsum csum = 0;
3538
3539 /* Copy header. */
3540 if (copy > 0) {
3541 if (copy > len)
3542 copy = len;
3543 csum = csum_partial_copy_nocheck(skb->data + offset, to,
3544 copy);
3545 if ((len -= copy) == 0)
3546 return csum;
3547 offset += copy;
3548 to += copy;
3549 pos = copy;
3550 }
3551
3552 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
3553 int end;
3554
3555 WARN_ON(start > offset + len);
3556
3557 end = start + skb_frag_size(&skb_shinfo(skb)->frags[i]);
3558 if ((copy = end - offset) > 0) {
3559 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
3560 u32 p_off, p_len, copied;
3561 struct page *p;
3562 __wsum csum2;
3563 u8 *vaddr;
3564
3565 if (copy > len)
3566 copy = len;
3567
3568 skb_frag_foreach_page(frag,
3569 skb_frag_off(frag) + offset - start,
3570 copy, p, p_off, p_len, copied) {
3571 vaddr = kmap_atomic(p);
3572 csum2 = csum_partial_copy_nocheck(vaddr + p_off,
3573 to + copied,
3574 p_len);
3575 kunmap_atomic(vaddr);
3576 csum = csum_block_add(csum, csum2, pos);
3577 pos += p_len;
3578 }
3579
3580 if (!(len -= copy))
3581 return csum;
3582 offset += copy;
3583 to += copy;
3584 }
3585 start = end;
3586 }
3587
3588 skb_walk_frags(skb, frag_iter) {
3589 __wsum csum2;
3590 int end;
3591
3592 WARN_ON(start > offset + len);
3593
3594 end = start + frag_iter->len;
3595 if ((copy = end - offset) > 0) {
3596 if (copy > len)
3597 copy = len;
3598 csum2 = skb_copy_and_csum_bits(frag_iter,
3599 offset - start,
3600 to, copy);
3601 csum = csum_block_add(csum, csum2, pos);
3602 if ((len -= copy) == 0)
3603 return csum;
3604 offset += copy;
3605 to += copy;
3606 pos += copy;
3607 }
3608 start = end;
3609 }
3610 BUG_ON(len);
3611 return csum;
3612}
3613EXPORT_SYMBOL(skb_copy_and_csum_bits);
3614
3615__sum16 __skb_checksum_complete_head(struct sk_buff *skb, int len)
3616{
3617 __sum16 sum;
3618
3619 sum = csum_fold(skb_checksum(skb, 0, len, skb->csum));
3620 /* See comments in __skb_checksum_complete(). */
3621 if (likely(!sum)) {
3622 if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE) &&
3623 !skb->csum_complete_sw)
3624 netdev_rx_csum_fault(skb->dev, skb);
3625 }
3626 if (!skb_shared(skb))
3627 skb->csum_valid = !sum;
3628 return sum;
3629}
3630EXPORT_SYMBOL(__skb_checksum_complete_head);
3631
3632/* This function assumes skb->csum already holds pseudo header's checksum,
3633 * which has been changed from the hardware checksum, for example, by
3634 * __skb_checksum_validate_complete(). And, the original skb->csum must
3635 * have been validated unsuccessfully for CHECKSUM_COMPLETE case.
3636 *
3637 * It returns non-zero if the recomputed checksum is still invalid, otherwise
3638 * zero. The new checksum is stored back into skb->csum unless the skb is
3639 * shared.
3640 */
3641__sum16 __skb_checksum_complete(struct sk_buff *skb)
3642{
3643 __wsum csum;
3644 __sum16 sum;
3645
3646 csum = skb_checksum(skb, 0, skb->len, 0);
3647
3648 sum = csum_fold(csum_add(skb->csum, csum));
3649 /* This check is inverted, because we already knew the hardware
3650 * checksum is invalid before calling this function. So, if the
3651 * re-computed checksum is valid instead, then we have a mismatch
3652 * between the original skb->csum and skb_checksum(). This means either
3653 * the original hardware checksum is incorrect or we screw up skb->csum
3654 * when moving skb->data around.
3655 */
3656 if (likely(!sum)) {
3657 if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE) &&
3658 !skb->csum_complete_sw)
3659 netdev_rx_csum_fault(skb->dev, skb);
3660 }
3661
3662 if (!skb_shared(skb)) {
3663 /* Save full packet checksum */
3664 skb->csum = csum;
3665 skb->ip_summed = CHECKSUM_COMPLETE;
3666 skb->csum_complete_sw = 1;
3667 skb->csum_valid = !sum;
3668 }
3669
3670 return sum;
3671}
3672EXPORT_SYMBOL(__skb_checksum_complete);
3673
3674static __wsum warn_crc32c_csum_update(const void *buff, int len, __wsum sum)
3675{
3676 net_warn_ratelimited(
3677 "%s: attempt to compute crc32c without libcrc32c.ko\n",
3678 __func__);
3679 return 0;
3680}
3681
3682static __wsum warn_crc32c_csum_combine(__wsum csum, __wsum csum2,
3683 int offset, int len)
3684{
3685 net_warn_ratelimited(
3686 "%s: attempt to compute crc32c without libcrc32c.ko\n",
3687 __func__);
3688 return 0;
3689}
3690
3691static const struct skb_checksum_ops default_crc32c_ops = {
3692 .update = warn_crc32c_csum_update,
3693 .combine = warn_crc32c_csum_combine,
3694};
3695
3696const struct skb_checksum_ops *crc32c_csum_stub __read_mostly =
3697 &default_crc32c_ops;
3698EXPORT_SYMBOL(crc32c_csum_stub);
3699
3700 /**
3701 * skb_zerocopy_headlen - Calculate headroom needed for skb_zerocopy()
3702 * @from: source buffer
3703 *
3704 * Calculates the amount of linear headroom needed in the 'to' skb passed
3705 * into skb_zerocopy().
3706 */
3707unsigned int
3708skb_zerocopy_headlen(const struct sk_buff *from)
3709{
3710 unsigned int hlen = 0;
3711
3712 if (!from->head_frag ||
3713 skb_headlen(from) < L1_CACHE_BYTES ||
3714 skb_shinfo(from)->nr_frags >= MAX_SKB_FRAGS) {
3715 hlen = skb_headlen(from);
3716 if (!hlen)
3717 hlen = from->len;
3718 }
3719
3720 if (skb_has_frag_list(from))
3721 hlen = from->len;
3722
3723 return hlen;
3724}
3725EXPORT_SYMBOL_GPL(skb_zerocopy_headlen);
3726
3727/**
3728 * skb_zerocopy - Zero copy skb to skb
3729 * @to: destination buffer
3730 * @from: source buffer
3731 * @len: number of bytes to copy from source buffer
3732 * @hlen: size of linear headroom in destination buffer
3733 *
3734 * Copies up to `len` bytes from `from` to `to` by creating references
3735 * to the frags in the source buffer.
3736 *
3737 * The `hlen` as calculated by skb_zerocopy_headlen() specifies the
3738 * headroom in the `to` buffer.
3739 *
3740 * Return value:
3741 * 0: everything is OK
3742 * -ENOMEM: couldn't orphan frags of @from due to lack of memory
3743 * -EFAULT: skb_copy_bits() found some problem with skb geometry
3744 */
3745int
3746skb_zerocopy(struct sk_buff *to, struct sk_buff *from, int len, int hlen)
3747{
3748 int i, j = 0;
3749 int plen = 0; /* length of skb->head fragment */
3750 int ret;
3751 struct page *page;
3752 unsigned int offset;
3753
3754 BUG_ON(!from->head_frag && !hlen);
3755
3756 /* dont bother with small payloads */
3757 if (len <= skb_tailroom(to))
3758 return skb_copy_bits(from, 0, skb_put(to, len), len);
3759
3760 if (hlen) {
3761 ret = skb_copy_bits(from, 0, skb_put(to, hlen), hlen);
3762 if (unlikely(ret))
3763 return ret;
3764 len -= hlen;
3765 } else {
3766 plen = min_t(int, skb_headlen(from), len);
3767 if (plen) {
3768 page = virt_to_head_page(from->head);
3769 offset = from->data - (unsigned char *)page_address(page);
3770 __skb_fill_netmem_desc(to, 0, page_to_netmem(page),
3771 offset, plen);
3772 get_page(page);
3773 j = 1;
3774 len -= plen;
3775 }
3776 }
3777
3778 skb_len_add(to, len + plen);
3779
3780 if (unlikely(skb_orphan_frags(from, GFP_ATOMIC))) {
3781 skb_tx_error(from);
3782 return -ENOMEM;
3783 }
3784 skb_zerocopy_clone(to, from, GFP_ATOMIC);
3785
3786 for (i = 0; i < skb_shinfo(from)->nr_frags; i++) {
3787 int size;
3788
3789 if (!len)
3790 break;
3791 skb_shinfo(to)->frags[j] = skb_shinfo(from)->frags[i];
3792 size = min_t(int, skb_frag_size(&skb_shinfo(to)->frags[j]),
3793 len);
3794 skb_frag_size_set(&skb_shinfo(to)->frags[j], size);
3795 len -= size;
3796 skb_frag_ref(to, j);
3797 j++;
3798 }
3799 skb_shinfo(to)->nr_frags = j;
3800
3801 return 0;
3802}
3803EXPORT_SYMBOL_GPL(skb_zerocopy);
3804
3805void skb_copy_and_csum_dev(const struct sk_buff *skb, u8 *to)
3806{
3807 __wsum csum;
3808 long csstart;
3809
3810 if (skb->ip_summed == CHECKSUM_PARTIAL)
3811 csstart = skb_checksum_start_offset(skb);
3812 else
3813 csstart = skb_headlen(skb);
3814
3815 BUG_ON(csstart > skb_headlen(skb));
3816
3817 skb_copy_from_linear_data(skb, to, csstart);
3818
3819 csum = 0;
3820 if (csstart != skb->len)
3821 csum = skb_copy_and_csum_bits(skb, csstart, to + csstart,
3822 skb->len - csstart);
3823
3824 if (skb->ip_summed == CHECKSUM_PARTIAL) {
3825 long csstuff = csstart + skb->csum_offset;
3826
3827 *((__sum16 *)(to + csstuff)) = csum_fold(csum);
3828 }
3829}
3830EXPORT_SYMBOL(skb_copy_and_csum_dev);
3831
3832/**
3833 * skb_dequeue - remove from the head of the queue
3834 * @list: list to dequeue from
3835 *
3836 * Remove the head of the list. The list lock is taken so the function
3837 * may be used safely with other locking list functions. The head item is
3838 * returned or %NULL if the list is empty.
3839 */
3840
3841struct sk_buff *skb_dequeue(struct sk_buff_head *list)
3842{
3843 unsigned long flags;
3844 struct sk_buff *result;
3845
3846 spin_lock_irqsave(&list->lock, flags);
3847 result = __skb_dequeue(list);
3848 spin_unlock_irqrestore(&list->lock, flags);
3849 return result;
3850}
3851EXPORT_SYMBOL(skb_dequeue);
3852
3853/**
3854 * skb_dequeue_tail - remove from the tail of the queue
3855 * @list: list to dequeue from
3856 *
3857 * Remove the tail of the list. The list lock is taken so the function
3858 * may be used safely with other locking list functions. The tail item is
3859 * returned or %NULL if the list is empty.
3860 */
3861struct sk_buff *skb_dequeue_tail(struct sk_buff_head *list)
3862{
3863 unsigned long flags;
3864 struct sk_buff *result;
3865
3866 spin_lock_irqsave(&list->lock, flags);
3867 result = __skb_dequeue_tail(list);
3868 spin_unlock_irqrestore(&list->lock, flags);
3869 return result;
3870}
3871EXPORT_SYMBOL(skb_dequeue_tail);
3872
3873/**
3874 * skb_queue_purge_reason - empty a list
3875 * @list: list to empty
3876 * @reason: drop reason
3877 *
3878 * Delete all buffers on an &sk_buff list. Each buffer is removed from
3879 * the list and one reference dropped. This function takes the list
3880 * lock and is atomic with respect to other list locking functions.
3881 */
3882void skb_queue_purge_reason(struct sk_buff_head *list,
3883 enum skb_drop_reason reason)
3884{
3885 struct sk_buff_head tmp;
3886 unsigned long flags;
3887
3888 if (skb_queue_empty_lockless(list))
3889 return;
3890
3891 __skb_queue_head_init(&tmp);
3892
3893 spin_lock_irqsave(&list->lock, flags);
3894 skb_queue_splice_init(list, &tmp);
3895 spin_unlock_irqrestore(&list->lock, flags);
3896
3897 __skb_queue_purge_reason(&tmp, reason);
3898}
3899EXPORT_SYMBOL(skb_queue_purge_reason);
3900
3901/**
3902 * skb_rbtree_purge - empty a skb rbtree
3903 * @root: root of the rbtree to empty
3904 * Return value: the sum of truesizes of all purged skbs.
3905 *
3906 * Delete all buffers on an &sk_buff rbtree. Each buffer is removed from
3907 * the list and one reference dropped. This function does not take
3908 * any lock. Synchronization should be handled by the caller (e.g., TCP
3909 * out-of-order queue is protected by the socket lock).
3910 */
3911unsigned int skb_rbtree_purge(struct rb_root *root)
3912{
3913 struct rb_node *p = rb_first(root);
3914 unsigned int sum = 0;
3915
3916 while (p) {
3917 struct sk_buff *skb = rb_entry(p, struct sk_buff, rbnode);
3918
3919 p = rb_next(p);
3920 rb_erase(&skb->rbnode, root);
3921 sum += skb->truesize;
3922 kfree_skb(skb);
3923 }
3924 return sum;
3925}
3926
3927void skb_errqueue_purge(struct sk_buff_head *list)
3928{
3929 struct sk_buff *skb, *next;
3930 struct sk_buff_head kill;
3931 unsigned long flags;
3932
3933 __skb_queue_head_init(&kill);
3934
3935 spin_lock_irqsave(&list->lock, flags);
3936 skb_queue_walk_safe(list, skb, next) {
3937 if (SKB_EXT_ERR(skb)->ee.ee_origin == SO_EE_ORIGIN_ZEROCOPY ||
3938 SKB_EXT_ERR(skb)->ee.ee_origin == SO_EE_ORIGIN_TIMESTAMPING)
3939 continue;
3940 __skb_unlink(skb, list);
3941 __skb_queue_tail(&kill, skb);
3942 }
3943 spin_unlock_irqrestore(&list->lock, flags);
3944 __skb_queue_purge(&kill);
3945}
3946EXPORT_SYMBOL(skb_errqueue_purge);
3947
3948/**
3949 * skb_queue_head - queue a buffer at the list head
3950 * @list: list to use
3951 * @newsk: buffer to queue
3952 *
3953 * Queue a buffer at the start of the list. This function takes the
3954 * list lock and can be used safely with other locking &sk_buff functions
3955 * safely.
3956 *
3957 * A buffer cannot be placed on two lists at the same time.
3958 */
3959void skb_queue_head(struct sk_buff_head *list, struct sk_buff *newsk)
3960{
3961 unsigned long flags;
3962
3963 spin_lock_irqsave(&list->lock, flags);
3964 __skb_queue_head(list, newsk);
3965 spin_unlock_irqrestore(&list->lock, flags);
3966}
3967EXPORT_SYMBOL(skb_queue_head);
3968
3969/**
3970 * skb_queue_tail - queue a buffer at the list tail
3971 * @list: list to use
3972 * @newsk: buffer to queue
3973 *
3974 * Queue a buffer at the tail of the list. This function takes the
3975 * list lock and can be used safely with other locking &sk_buff functions
3976 * safely.
3977 *
3978 * A buffer cannot be placed on two lists at the same time.
3979 */
3980void skb_queue_tail(struct sk_buff_head *list, struct sk_buff *newsk)
3981{
3982 unsigned long flags;
3983
3984 spin_lock_irqsave(&list->lock, flags);
3985 __skb_queue_tail(list, newsk);
3986 spin_unlock_irqrestore(&list->lock, flags);
3987}
3988EXPORT_SYMBOL(skb_queue_tail);
3989
3990/**
3991 * skb_unlink - remove a buffer from a list
3992 * @skb: buffer to remove
3993 * @list: list to use
3994 *
3995 * Remove a packet from a list. The list locks are taken and this
3996 * function is atomic with respect to other list locked calls
3997 *
3998 * You must know what list the SKB is on.
3999 */
4000void skb_unlink(struct sk_buff *skb, struct sk_buff_head *list)
4001{
4002 unsigned long flags;
4003
4004 spin_lock_irqsave(&list->lock, flags);
4005 __skb_unlink(skb, list);
4006 spin_unlock_irqrestore(&list->lock, flags);
4007}
4008EXPORT_SYMBOL(skb_unlink);
4009
4010/**
4011 * skb_append - append a buffer
4012 * @old: buffer to insert after
4013 * @newsk: buffer to insert
4014 * @list: list to use
4015 *
4016 * Place a packet after a given packet in a list. The list locks are taken
4017 * and this function is atomic with respect to other list locked calls.
4018 * A buffer cannot be placed on two lists at the same time.
4019 */
4020void skb_append(struct sk_buff *old, struct sk_buff *newsk, struct sk_buff_head *list)
4021{
4022 unsigned long flags;
4023
4024 spin_lock_irqsave(&list->lock, flags);
4025 __skb_queue_after(list, old, newsk);
4026 spin_unlock_irqrestore(&list->lock, flags);
4027}
4028EXPORT_SYMBOL(skb_append);
4029
4030static inline void skb_split_inside_header(struct sk_buff *skb,
4031 struct sk_buff* skb1,
4032 const u32 len, const int pos)
4033{
4034 int i;
4035
4036 skb_copy_from_linear_data_offset(skb, len, skb_put(skb1, pos - len),
4037 pos - len);
4038 /* And move data appendix as is. */
4039 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
4040 skb_shinfo(skb1)->frags[i] = skb_shinfo(skb)->frags[i];
4041
4042 skb_shinfo(skb1)->nr_frags = skb_shinfo(skb)->nr_frags;
4043 skb_shinfo(skb)->nr_frags = 0;
4044 skb1->data_len = skb->data_len;
4045 skb1->len += skb1->data_len;
4046 skb->data_len = 0;
4047 skb->len = len;
4048 skb_set_tail_pointer(skb, len);
4049}
4050
4051static inline void skb_split_no_header(struct sk_buff *skb,
4052 struct sk_buff* skb1,
4053 const u32 len, int pos)
4054{
4055 int i, k = 0;
4056 const int nfrags = skb_shinfo(skb)->nr_frags;
4057
4058 skb_shinfo(skb)->nr_frags = 0;
4059 skb1->len = skb1->data_len = skb->len - len;
4060 skb->len = len;
4061 skb->data_len = len - pos;
4062
4063 for (i = 0; i < nfrags; i++) {
4064 int size = skb_frag_size(&skb_shinfo(skb)->frags[i]);
4065
4066 if (pos + size > len) {
4067 skb_shinfo(skb1)->frags[k] = skb_shinfo(skb)->frags[i];
4068
4069 if (pos < len) {
4070 /* Split frag.
4071 * We have two variants in this case:
4072 * 1. Move all the frag to the second
4073 * part, if it is possible. F.e.
4074 * this approach is mandatory for TUX,
4075 * where splitting is expensive.
4076 * 2. Split is accurately. We make this.
4077 */
4078 skb_frag_ref(skb, i);
4079 skb_frag_off_add(&skb_shinfo(skb1)->frags[0], len - pos);
4080 skb_frag_size_sub(&skb_shinfo(skb1)->frags[0], len - pos);
4081 skb_frag_size_set(&skb_shinfo(skb)->frags[i], len - pos);
4082 skb_shinfo(skb)->nr_frags++;
4083 }
4084 k++;
4085 } else
4086 skb_shinfo(skb)->nr_frags++;
4087 pos += size;
4088 }
4089 skb_shinfo(skb1)->nr_frags = k;
4090}
4091
4092/**
4093 * skb_split - Split fragmented skb to two parts at length len.
4094 * @skb: the buffer to split
4095 * @skb1: the buffer to receive the second part
4096 * @len: new length for skb
4097 */
4098void skb_split(struct sk_buff *skb, struct sk_buff *skb1, const u32 len)
4099{
4100 int pos = skb_headlen(skb);
4101 const int zc_flags = SKBFL_SHARED_FRAG | SKBFL_PURE_ZEROCOPY;
4102
4103 skb_zcopy_downgrade_managed(skb);
4104
4105 skb_shinfo(skb1)->flags |= skb_shinfo(skb)->flags & zc_flags;
4106 skb_zerocopy_clone(skb1, skb, 0);
4107 if (len < pos) /* Split line is inside header. */
4108 skb_split_inside_header(skb, skb1, len, pos);
4109 else /* Second chunk has no header, nothing to copy. */
4110 skb_split_no_header(skb, skb1, len, pos);
4111}
4112EXPORT_SYMBOL(skb_split);
4113
4114/* Shifting from/to a cloned skb is a no-go.
4115 *
4116 * Caller cannot keep skb_shinfo related pointers past calling here!
4117 */
4118static int skb_prepare_for_shift(struct sk_buff *skb)
4119{
4120 return skb_unclone_keeptruesize(skb, GFP_ATOMIC);
4121}
4122
4123/**
4124 * skb_shift - Shifts paged data partially from skb to another
4125 * @tgt: buffer into which tail data gets added
4126 * @skb: buffer from which the paged data comes from
4127 * @shiftlen: shift up to this many bytes
4128 *
4129 * Attempts to shift up to shiftlen worth of bytes, which may be less than
4130 * the length of the skb, from skb to tgt. Returns number bytes shifted.
4131 * It's up to caller to free skb if everything was shifted.
4132 *
4133 * If @tgt runs out of frags, the whole operation is aborted.
4134 *
4135 * Skb cannot include anything else but paged data while tgt is allowed
4136 * to have non-paged data as well.
4137 *
4138 * TODO: full sized shift could be optimized but that would need
4139 * specialized skb free'er to handle frags without up-to-date nr_frags.
4140 */
4141int skb_shift(struct sk_buff *tgt, struct sk_buff *skb, int shiftlen)
4142{
4143 int from, to, merge, todo;
4144 skb_frag_t *fragfrom, *fragto;
4145
4146 BUG_ON(shiftlen > skb->len);
4147
4148 if (skb_headlen(skb))
4149 return 0;
4150 if (skb_zcopy(tgt) || skb_zcopy(skb))
4151 return 0;
4152
4153 todo = shiftlen;
4154 from = 0;
4155 to = skb_shinfo(tgt)->nr_frags;
4156 fragfrom = &skb_shinfo(skb)->frags[from];
4157
4158 /* Actual merge is delayed until the point when we know we can
4159 * commit all, so that we don't have to undo partial changes
4160 */
4161 if (!to ||
4162 !skb_can_coalesce(tgt, to, skb_frag_page(fragfrom),
4163 skb_frag_off(fragfrom))) {
4164 merge = -1;
4165 } else {
4166 merge = to - 1;
4167
4168 todo -= skb_frag_size(fragfrom);
4169 if (todo < 0) {
4170 if (skb_prepare_for_shift(skb) ||
4171 skb_prepare_for_shift(tgt))
4172 return 0;
4173
4174 /* All previous frag pointers might be stale! */
4175 fragfrom = &skb_shinfo(skb)->frags[from];
4176 fragto = &skb_shinfo(tgt)->frags[merge];
4177
4178 skb_frag_size_add(fragto, shiftlen);
4179 skb_frag_size_sub(fragfrom, shiftlen);
4180 skb_frag_off_add(fragfrom, shiftlen);
4181
4182 goto onlymerged;
4183 }
4184
4185 from++;
4186 }
4187
4188 /* Skip full, not-fitting skb to avoid expensive operations */
4189 if ((shiftlen == skb->len) &&
4190 (skb_shinfo(skb)->nr_frags - from) > (MAX_SKB_FRAGS - to))
4191 return 0;
4192
4193 if (skb_prepare_for_shift(skb) || skb_prepare_for_shift(tgt))
4194 return 0;
4195
4196 while ((todo > 0) && (from < skb_shinfo(skb)->nr_frags)) {
4197 if (to == MAX_SKB_FRAGS)
4198 return 0;
4199
4200 fragfrom = &skb_shinfo(skb)->frags[from];
4201 fragto = &skb_shinfo(tgt)->frags[to];
4202
4203 if (todo >= skb_frag_size(fragfrom)) {
4204 *fragto = *fragfrom;
4205 todo -= skb_frag_size(fragfrom);
4206 from++;
4207 to++;
4208
4209 } else {
4210 __skb_frag_ref(fragfrom);
4211 skb_frag_page_copy(fragto, fragfrom);
4212 skb_frag_off_copy(fragto, fragfrom);
4213 skb_frag_size_set(fragto, todo);
4214
4215 skb_frag_off_add(fragfrom, todo);
4216 skb_frag_size_sub(fragfrom, todo);
4217 todo = 0;
4218
4219 to++;
4220 break;
4221 }
4222 }
4223
4224 /* Ready to "commit" this state change to tgt */
4225 skb_shinfo(tgt)->nr_frags = to;
4226
4227 if (merge >= 0) {
4228 fragfrom = &skb_shinfo(skb)->frags[0];
4229 fragto = &skb_shinfo(tgt)->frags[merge];
4230
4231 skb_frag_size_add(fragto, skb_frag_size(fragfrom));
4232 __skb_frag_unref(fragfrom, skb->pp_recycle);
4233 }
4234
4235 /* Reposition in the original skb */
4236 to = 0;
4237 while (from < skb_shinfo(skb)->nr_frags)
4238 skb_shinfo(skb)->frags[to++] = skb_shinfo(skb)->frags[from++];
4239 skb_shinfo(skb)->nr_frags = to;
4240
4241 BUG_ON(todo > 0 && !skb_shinfo(skb)->nr_frags);
4242
4243onlymerged:
4244 /* Most likely the tgt won't ever need its checksum anymore, skb on
4245 * the other hand might need it if it needs to be resent
4246 */
4247 tgt->ip_summed = CHECKSUM_PARTIAL;
4248 skb->ip_summed = CHECKSUM_PARTIAL;
4249
4250 skb_len_add(skb, -shiftlen);
4251 skb_len_add(tgt, shiftlen);
4252
4253 return shiftlen;
4254}
4255
4256/**
4257 * skb_prepare_seq_read - Prepare a sequential read of skb data
4258 * @skb: the buffer to read
4259 * @from: lower offset of data to be read
4260 * @to: upper offset of data to be read
4261 * @st: state variable
4262 *
4263 * Initializes the specified state variable. Must be called before
4264 * invoking skb_seq_read() for the first time.
4265 */
4266void skb_prepare_seq_read(struct sk_buff *skb, unsigned int from,
4267 unsigned int to, struct skb_seq_state *st)
4268{
4269 st->lower_offset = from;
4270 st->upper_offset = to;
4271 st->root_skb = st->cur_skb = skb;
4272 st->frag_idx = st->stepped_offset = 0;
4273 st->frag_data = NULL;
4274 st->frag_off = 0;
4275}
4276EXPORT_SYMBOL(skb_prepare_seq_read);
4277
4278/**
4279 * skb_seq_read - Sequentially read skb data
4280 * @consumed: number of bytes consumed by the caller so far
4281 * @data: destination pointer for data to be returned
4282 * @st: state variable
4283 *
4284 * Reads a block of skb data at @consumed relative to the
4285 * lower offset specified to skb_prepare_seq_read(). Assigns
4286 * the head of the data block to @data and returns the length
4287 * of the block or 0 if the end of the skb data or the upper
4288 * offset has been reached.
4289 *
4290 * The caller is not required to consume all of the data
4291 * returned, i.e. @consumed is typically set to the number
4292 * of bytes already consumed and the next call to
4293 * skb_seq_read() will return the remaining part of the block.
4294 *
4295 * Note 1: The size of each block of data returned can be arbitrary,
4296 * this limitation is the cost for zerocopy sequential
4297 * reads of potentially non linear data.
4298 *
4299 * Note 2: Fragment lists within fragments are not implemented
4300 * at the moment, state->root_skb could be replaced with
4301 * a stack for this purpose.
4302 */
4303unsigned int skb_seq_read(unsigned int consumed, const u8 **data,
4304 struct skb_seq_state *st)
4305{
4306 unsigned int block_limit, abs_offset = consumed + st->lower_offset;
4307 skb_frag_t *frag;
4308
4309 if (unlikely(abs_offset >= st->upper_offset)) {
4310 if (st->frag_data) {
4311 kunmap_atomic(st->frag_data);
4312 st->frag_data = NULL;
4313 }
4314 return 0;
4315 }
4316
4317next_skb:
4318 block_limit = skb_headlen(st->cur_skb) + st->stepped_offset;
4319
4320 if (abs_offset < block_limit && !st->frag_data) {
4321 *data = st->cur_skb->data + (abs_offset - st->stepped_offset);
4322 return block_limit - abs_offset;
4323 }
4324
4325 if (st->frag_idx == 0 && !st->frag_data)
4326 st->stepped_offset += skb_headlen(st->cur_skb);
4327
4328 while (st->frag_idx < skb_shinfo(st->cur_skb)->nr_frags) {
4329 unsigned int pg_idx, pg_off, pg_sz;
4330
4331 frag = &skb_shinfo(st->cur_skb)->frags[st->frag_idx];
4332
4333 pg_idx = 0;
4334 pg_off = skb_frag_off(frag);
4335 pg_sz = skb_frag_size(frag);
4336
4337 if (skb_frag_must_loop(skb_frag_page(frag))) {
4338 pg_idx = (pg_off + st->frag_off) >> PAGE_SHIFT;
4339 pg_off = offset_in_page(pg_off + st->frag_off);
4340 pg_sz = min_t(unsigned int, pg_sz - st->frag_off,
4341 PAGE_SIZE - pg_off);
4342 }
4343
4344 block_limit = pg_sz + st->stepped_offset;
4345 if (abs_offset < block_limit) {
4346 if (!st->frag_data)
4347 st->frag_data = kmap_atomic(skb_frag_page(frag) + pg_idx);
4348
4349 *data = (u8 *)st->frag_data + pg_off +
4350 (abs_offset - st->stepped_offset);
4351
4352 return block_limit - abs_offset;
4353 }
4354
4355 if (st->frag_data) {
4356 kunmap_atomic(st->frag_data);
4357 st->frag_data = NULL;
4358 }
4359
4360 st->stepped_offset += pg_sz;
4361 st->frag_off += pg_sz;
4362 if (st->frag_off == skb_frag_size(frag)) {
4363 st->frag_off = 0;
4364 st->frag_idx++;
4365 }
4366 }
4367
4368 if (st->frag_data) {
4369 kunmap_atomic(st->frag_data);
4370 st->frag_data = NULL;
4371 }
4372
4373 if (st->root_skb == st->cur_skb && skb_has_frag_list(st->root_skb)) {
4374 st->cur_skb = skb_shinfo(st->root_skb)->frag_list;
4375 st->frag_idx = 0;
4376 goto next_skb;
4377 } else if (st->cur_skb->next) {
4378 st->cur_skb = st->cur_skb->next;
4379 st->frag_idx = 0;
4380 goto next_skb;
4381 }
4382
4383 return 0;
4384}
4385EXPORT_SYMBOL(skb_seq_read);
4386
4387/**
4388 * skb_abort_seq_read - Abort a sequential read of skb data
4389 * @st: state variable
4390 *
4391 * Must be called if skb_seq_read() was not called until it
4392 * returned 0.
4393 */
4394void skb_abort_seq_read(struct skb_seq_state *st)
4395{
4396 if (st->frag_data)
4397 kunmap_atomic(st->frag_data);
4398}
4399EXPORT_SYMBOL(skb_abort_seq_read);
4400
4401#define TS_SKB_CB(state) ((struct skb_seq_state *) &((state)->cb))
4402
4403static unsigned int skb_ts_get_next_block(unsigned int offset, const u8 **text,
4404 struct ts_config *conf,
4405 struct ts_state *state)
4406{
4407 return skb_seq_read(offset, text, TS_SKB_CB(state));
4408}
4409
4410static void skb_ts_finish(struct ts_config *conf, struct ts_state *state)
4411{
4412 skb_abort_seq_read(TS_SKB_CB(state));
4413}
4414
4415/**
4416 * skb_find_text - Find a text pattern in skb data
4417 * @skb: the buffer to look in
4418 * @from: search offset
4419 * @to: search limit
4420 * @config: textsearch configuration
4421 *
4422 * Finds a pattern in the skb data according to the specified
4423 * textsearch configuration. Use textsearch_next() to retrieve
4424 * subsequent occurrences of the pattern. Returns the offset
4425 * to the first occurrence or UINT_MAX if no match was found.
4426 */
4427unsigned int skb_find_text(struct sk_buff *skb, unsigned int from,
4428 unsigned int to, struct ts_config *config)
4429{
4430 unsigned int patlen = config->ops->get_pattern_len(config);
4431 struct ts_state state;
4432 unsigned int ret;
4433
4434 BUILD_BUG_ON(sizeof(struct skb_seq_state) > sizeof(state.cb));
4435
4436 config->get_next_block = skb_ts_get_next_block;
4437 config->finish = skb_ts_finish;
4438
4439 skb_prepare_seq_read(skb, from, to, TS_SKB_CB(&state));
4440
4441 ret = textsearch_find(config, &state);
4442 return (ret + patlen <= to - from ? ret : UINT_MAX);
4443}
4444EXPORT_SYMBOL(skb_find_text);
4445
4446int skb_append_pagefrags(struct sk_buff *skb, struct page *page,
4447 int offset, size_t size, size_t max_frags)
4448{
4449 int i = skb_shinfo(skb)->nr_frags;
4450
4451 if (skb_can_coalesce(skb, i, page, offset)) {
4452 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], size);
4453 } else if (i < max_frags) {
4454 skb_zcopy_downgrade_managed(skb);
4455 get_page(page);
4456 skb_fill_page_desc_noacc(skb, i, page, offset, size);
4457 } else {
4458 return -EMSGSIZE;
4459 }
4460
4461 return 0;
4462}
4463EXPORT_SYMBOL_GPL(skb_append_pagefrags);
4464
4465/**
4466 * skb_pull_rcsum - pull skb and update receive checksum
4467 * @skb: buffer to update
4468 * @len: length of data pulled
4469 *
4470 * This function performs an skb_pull on the packet and updates
4471 * the CHECKSUM_COMPLETE checksum. It should be used on
4472 * receive path processing instead of skb_pull unless you know
4473 * that the checksum difference is zero (e.g., a valid IP header)
4474 * or you are setting ip_summed to CHECKSUM_NONE.
4475 */
4476void *skb_pull_rcsum(struct sk_buff *skb, unsigned int len)
4477{
4478 unsigned char *data = skb->data;
4479
4480 BUG_ON(len > skb->len);
4481 __skb_pull(skb, len);
4482 skb_postpull_rcsum(skb, data, len);
4483 return skb->data;
4484}
4485EXPORT_SYMBOL_GPL(skb_pull_rcsum);
4486
4487static inline skb_frag_t skb_head_frag_to_page_desc(struct sk_buff *frag_skb)
4488{
4489 skb_frag_t head_frag;
4490 struct page *page;
4491
4492 page = virt_to_head_page(frag_skb->head);
4493 skb_frag_fill_page_desc(&head_frag, page, frag_skb->data -
4494 (unsigned char *)page_address(page),
4495 skb_headlen(frag_skb));
4496 return head_frag;
4497}
4498
4499struct sk_buff *skb_segment_list(struct sk_buff *skb,
4500 netdev_features_t features,
4501 unsigned int offset)
4502{
4503 struct sk_buff *list_skb = skb_shinfo(skb)->frag_list;
4504 unsigned int tnl_hlen = skb_tnl_header_len(skb);
4505 unsigned int delta_truesize = 0;
4506 unsigned int delta_len = 0;
4507 struct sk_buff *tail = NULL;
4508 struct sk_buff *nskb, *tmp;
4509 int len_diff, err;
4510
4511 skb_push(skb, -skb_network_offset(skb) + offset);
4512
4513 /* Ensure the head is writeable before touching the shared info */
4514 err = skb_unclone(skb, GFP_ATOMIC);
4515 if (err)
4516 goto err_linearize;
4517
4518 skb_shinfo(skb)->frag_list = NULL;
4519
4520 while (list_skb) {
4521 nskb = list_skb;
4522 list_skb = list_skb->next;
4523
4524 err = 0;
4525 delta_truesize += nskb->truesize;
4526 if (skb_shared(nskb)) {
4527 tmp = skb_clone(nskb, GFP_ATOMIC);
4528 if (tmp) {
4529 consume_skb(nskb);
4530 nskb = tmp;
4531 err = skb_unclone(nskb, GFP_ATOMIC);
4532 } else {
4533 err = -ENOMEM;
4534 }
4535 }
4536
4537 if (!tail)
4538 skb->next = nskb;
4539 else
4540 tail->next = nskb;
4541
4542 if (unlikely(err)) {
4543 nskb->next = list_skb;
4544 goto err_linearize;
4545 }
4546
4547 tail = nskb;
4548
4549 delta_len += nskb->len;
4550
4551 skb_push(nskb, -skb_network_offset(nskb) + offset);
4552
4553 skb_release_head_state(nskb);
4554 len_diff = skb_network_header_len(nskb) - skb_network_header_len(skb);
4555 __copy_skb_header(nskb, skb);
4556
4557 skb_headers_offset_update(nskb, skb_headroom(nskb) - skb_headroom(skb));
4558 nskb->transport_header += len_diff;
4559 skb_copy_from_linear_data_offset(skb, -tnl_hlen,
4560 nskb->data - tnl_hlen,
4561 offset + tnl_hlen);
4562
4563 if (skb_needs_linearize(nskb, features) &&
4564 __skb_linearize(nskb))
4565 goto err_linearize;
4566 }
4567
4568 skb->truesize = skb->truesize - delta_truesize;
4569 skb->data_len = skb->data_len - delta_len;
4570 skb->len = skb->len - delta_len;
4571
4572 skb_gso_reset(skb);
4573
4574 skb->prev = tail;
4575
4576 if (skb_needs_linearize(skb, features) &&
4577 __skb_linearize(skb))
4578 goto err_linearize;
4579
4580 skb_get(skb);
4581
4582 return skb;
4583
4584err_linearize:
4585 kfree_skb_list(skb->next);
4586 skb->next = NULL;
4587 return ERR_PTR(-ENOMEM);
4588}
4589EXPORT_SYMBOL_GPL(skb_segment_list);
4590
4591/**
4592 * skb_segment - Perform protocol segmentation on skb.
4593 * @head_skb: buffer to segment
4594 * @features: features for the output path (see dev->features)
4595 *
4596 * This function performs segmentation on the given skb. It returns
4597 * a pointer to the first in a list of new skbs for the segments.
4598 * In case of error it returns ERR_PTR(err).
4599 */
4600struct sk_buff *skb_segment(struct sk_buff *head_skb,
4601 netdev_features_t features)
4602{
4603 struct sk_buff *segs = NULL;
4604 struct sk_buff *tail = NULL;
4605 struct sk_buff *list_skb = skb_shinfo(head_skb)->frag_list;
4606 unsigned int mss = skb_shinfo(head_skb)->gso_size;
4607 unsigned int doffset = head_skb->data - skb_mac_header(head_skb);
4608 unsigned int offset = doffset;
4609 unsigned int tnl_hlen = skb_tnl_header_len(head_skb);
4610 unsigned int partial_segs = 0;
4611 unsigned int headroom;
4612 unsigned int len = head_skb->len;
4613 struct sk_buff *frag_skb;
4614 skb_frag_t *frag;
4615 __be16 proto;
4616 bool csum, sg;
4617 int err = -ENOMEM;
4618 int i = 0;
4619 int nfrags, pos;
4620
4621 if ((skb_shinfo(head_skb)->gso_type & SKB_GSO_DODGY) &&
4622 mss != GSO_BY_FRAGS && mss != skb_headlen(head_skb)) {
4623 struct sk_buff *check_skb;
4624
4625 for (check_skb = list_skb; check_skb; check_skb = check_skb->next) {
4626 if (skb_headlen(check_skb) && !check_skb->head_frag) {
4627 /* gso_size is untrusted, and we have a frag_list with
4628 * a linear non head_frag item.
4629 *
4630 * If head_skb's headlen does not fit requested gso_size,
4631 * it means that the frag_list members do NOT terminate
4632 * on exact gso_size boundaries. Hence we cannot perform
4633 * skb_frag_t page sharing. Therefore we must fallback to
4634 * copying the frag_list skbs; we do so by disabling SG.
4635 */
4636 features &= ~NETIF_F_SG;
4637 break;
4638 }
4639 }
4640 }
4641
4642 __skb_push(head_skb, doffset);
4643 proto = skb_network_protocol(head_skb, NULL);
4644 if (unlikely(!proto))
4645 return ERR_PTR(-EINVAL);
4646
4647 sg = !!(features & NETIF_F_SG);
4648 csum = !!can_checksum_protocol(features, proto);
4649
4650 if (sg && csum && (mss != GSO_BY_FRAGS)) {
4651 if (!(features & NETIF_F_GSO_PARTIAL)) {
4652 struct sk_buff *iter;
4653 unsigned int frag_len;
4654
4655 if (!list_skb ||
4656 !net_gso_ok(features, skb_shinfo(head_skb)->gso_type))
4657 goto normal;
4658
4659 /* If we get here then all the required
4660 * GSO features except frag_list are supported.
4661 * Try to split the SKB to multiple GSO SKBs
4662 * with no frag_list.
4663 * Currently we can do that only when the buffers don't
4664 * have a linear part and all the buffers except
4665 * the last are of the same length.
4666 */
4667 frag_len = list_skb->len;
4668 skb_walk_frags(head_skb, iter) {
4669 if (frag_len != iter->len && iter->next)
4670 goto normal;
4671 if (skb_headlen(iter) && !iter->head_frag)
4672 goto normal;
4673
4674 len -= iter->len;
4675 }
4676
4677 if (len != frag_len)
4678 goto normal;
4679 }
4680
4681 /* GSO partial only requires that we trim off any excess that
4682 * doesn't fit into an MSS sized block, so take care of that
4683 * now.
4684 * Cap len to not accidentally hit GSO_BY_FRAGS.
4685 */
4686 partial_segs = min(len, GSO_BY_FRAGS - 1) / mss;
4687 if (partial_segs > 1)
4688 mss *= partial_segs;
4689 else
4690 partial_segs = 0;
4691 }
4692
4693normal:
4694 headroom = skb_headroom(head_skb);
4695 pos = skb_headlen(head_skb);
4696
4697 if (skb_orphan_frags(head_skb, GFP_ATOMIC))
4698 return ERR_PTR(-ENOMEM);
4699
4700 nfrags = skb_shinfo(head_skb)->nr_frags;
4701 frag = skb_shinfo(head_skb)->frags;
4702 frag_skb = head_skb;
4703
4704 do {
4705 struct sk_buff *nskb;
4706 skb_frag_t *nskb_frag;
4707 int hsize;
4708 int size;
4709
4710 if (unlikely(mss == GSO_BY_FRAGS)) {
4711 len = list_skb->len;
4712 } else {
4713 len = head_skb->len - offset;
4714 if (len > mss)
4715 len = mss;
4716 }
4717
4718 hsize = skb_headlen(head_skb) - offset;
4719
4720 if (hsize <= 0 && i >= nfrags && skb_headlen(list_skb) &&
4721 (skb_headlen(list_skb) == len || sg)) {
4722 BUG_ON(skb_headlen(list_skb) > len);
4723
4724 nskb = skb_clone(list_skb, GFP_ATOMIC);
4725 if (unlikely(!nskb))
4726 goto err;
4727
4728 i = 0;
4729 nfrags = skb_shinfo(list_skb)->nr_frags;
4730 frag = skb_shinfo(list_skb)->frags;
4731 frag_skb = list_skb;
4732 pos += skb_headlen(list_skb);
4733
4734 while (pos < offset + len) {
4735 BUG_ON(i >= nfrags);
4736
4737 size = skb_frag_size(frag);
4738 if (pos + size > offset + len)
4739 break;
4740
4741 i++;
4742 pos += size;
4743 frag++;
4744 }
4745
4746 list_skb = list_skb->next;
4747
4748 if (unlikely(pskb_trim(nskb, len))) {
4749 kfree_skb(nskb);
4750 goto err;
4751 }
4752
4753 hsize = skb_end_offset(nskb);
4754 if (skb_cow_head(nskb, doffset + headroom)) {
4755 kfree_skb(nskb);
4756 goto err;
4757 }
4758
4759 nskb->truesize += skb_end_offset(nskb) - hsize;
4760 skb_release_head_state(nskb);
4761 __skb_push(nskb, doffset);
4762 } else {
4763 if (hsize < 0)
4764 hsize = 0;
4765 if (hsize > len || !sg)
4766 hsize = len;
4767
4768 nskb = __alloc_skb(hsize + doffset + headroom,
4769 GFP_ATOMIC, skb_alloc_rx_flag(head_skb),
4770 NUMA_NO_NODE);
4771
4772 if (unlikely(!nskb))
4773 goto err;
4774
4775 skb_reserve(nskb, headroom);
4776 __skb_put(nskb, doffset);
4777 }
4778
4779 if (segs)
4780 tail->next = nskb;
4781 else
4782 segs = nskb;
4783 tail = nskb;
4784
4785 __copy_skb_header(nskb, head_skb);
4786
4787 skb_headers_offset_update(nskb, skb_headroom(nskb) - headroom);
4788 skb_reset_mac_len(nskb);
4789
4790 skb_copy_from_linear_data_offset(head_skb, -tnl_hlen,
4791 nskb->data - tnl_hlen,
4792 doffset + tnl_hlen);
4793
4794 if (nskb->len == len + doffset)
4795 goto perform_csum_check;
4796
4797 if (!sg) {
4798 if (!csum) {
4799 if (!nskb->remcsum_offload)
4800 nskb->ip_summed = CHECKSUM_NONE;
4801 SKB_GSO_CB(nskb)->csum =
4802 skb_copy_and_csum_bits(head_skb, offset,
4803 skb_put(nskb,
4804 len),
4805 len);
4806 SKB_GSO_CB(nskb)->csum_start =
4807 skb_headroom(nskb) + doffset;
4808 } else {
4809 if (skb_copy_bits(head_skb, offset, skb_put(nskb, len), len))
4810 goto err;
4811 }
4812 continue;
4813 }
4814
4815 nskb_frag = skb_shinfo(nskb)->frags;
4816
4817 skb_copy_from_linear_data_offset(head_skb, offset,
4818 skb_put(nskb, hsize), hsize);
4819
4820 skb_shinfo(nskb)->flags |= skb_shinfo(head_skb)->flags &
4821 SKBFL_SHARED_FRAG;
4822
4823 if (skb_zerocopy_clone(nskb, frag_skb, GFP_ATOMIC))
4824 goto err;
4825
4826 while (pos < offset + len) {
4827 if (i >= nfrags) {
4828 if (skb_orphan_frags(list_skb, GFP_ATOMIC) ||
4829 skb_zerocopy_clone(nskb, list_skb,
4830 GFP_ATOMIC))
4831 goto err;
4832
4833 i = 0;
4834 nfrags = skb_shinfo(list_skb)->nr_frags;
4835 frag = skb_shinfo(list_skb)->frags;
4836 frag_skb = list_skb;
4837 if (!skb_headlen(list_skb)) {
4838 BUG_ON(!nfrags);
4839 } else {
4840 BUG_ON(!list_skb->head_frag);
4841
4842 /* to make room for head_frag. */
4843 i--;
4844 frag--;
4845 }
4846
4847 list_skb = list_skb->next;
4848 }
4849
4850 if (unlikely(skb_shinfo(nskb)->nr_frags >=
4851 MAX_SKB_FRAGS)) {
4852 net_warn_ratelimited(
4853 "skb_segment: too many frags: %u %u\n",
4854 pos, mss);
4855 err = -EINVAL;
4856 goto err;
4857 }
4858
4859 *nskb_frag = (i < 0) ? skb_head_frag_to_page_desc(frag_skb) : *frag;
4860 __skb_frag_ref(nskb_frag);
4861 size = skb_frag_size(nskb_frag);
4862
4863 if (pos < offset) {
4864 skb_frag_off_add(nskb_frag, offset - pos);
4865 skb_frag_size_sub(nskb_frag, offset - pos);
4866 }
4867
4868 skb_shinfo(nskb)->nr_frags++;
4869
4870 if (pos + size <= offset + len) {
4871 i++;
4872 frag++;
4873 pos += size;
4874 } else {
4875 skb_frag_size_sub(nskb_frag, pos + size - (offset + len));
4876 goto skip_fraglist;
4877 }
4878
4879 nskb_frag++;
4880 }
4881
4882skip_fraglist:
4883 nskb->data_len = len - hsize;
4884 nskb->len += nskb->data_len;
4885 nskb->truesize += nskb->data_len;
4886
4887perform_csum_check:
4888 if (!csum) {
4889 if (skb_has_shared_frag(nskb) &&
4890 __skb_linearize(nskb))
4891 goto err;
4892
4893 if (!nskb->remcsum_offload)
4894 nskb->ip_summed = CHECKSUM_NONE;
4895 SKB_GSO_CB(nskb)->csum =
4896 skb_checksum(nskb, doffset,
4897 nskb->len - doffset, 0);
4898 SKB_GSO_CB(nskb)->csum_start =
4899 skb_headroom(nskb) + doffset;
4900 }
4901 } while ((offset += len) < head_skb->len);
4902
4903 /* Some callers want to get the end of the list.
4904 * Put it in segs->prev to avoid walking the list.
4905 * (see validate_xmit_skb_list() for example)
4906 */
4907 segs->prev = tail;
4908
4909 if (partial_segs) {
4910 struct sk_buff *iter;
4911 int type = skb_shinfo(head_skb)->gso_type;
4912 unsigned short gso_size = skb_shinfo(head_skb)->gso_size;
4913
4914 /* Update type to add partial and then remove dodgy if set */
4915 type |= (features & NETIF_F_GSO_PARTIAL) / NETIF_F_GSO_PARTIAL * SKB_GSO_PARTIAL;
4916 type &= ~SKB_GSO_DODGY;
4917
4918 /* Update GSO info and prepare to start updating headers on
4919 * our way back down the stack of protocols.
4920 */
4921 for (iter = segs; iter; iter = iter->next) {
4922 skb_shinfo(iter)->gso_size = gso_size;
4923 skb_shinfo(iter)->gso_segs = partial_segs;
4924 skb_shinfo(iter)->gso_type = type;
4925 SKB_GSO_CB(iter)->data_offset = skb_headroom(iter) + doffset;
4926 }
4927
4928 if (tail->len - doffset <= gso_size)
4929 skb_shinfo(tail)->gso_size = 0;
4930 else if (tail != segs)
4931 skb_shinfo(tail)->gso_segs = DIV_ROUND_UP(tail->len - doffset, gso_size);
4932 }
4933
4934 /* Following permits correct backpressure, for protocols
4935 * using skb_set_owner_w().
4936 * Idea is to tranfert ownership from head_skb to last segment.
4937 */
4938 if (head_skb->destructor == sock_wfree) {
4939 swap(tail->truesize, head_skb->truesize);
4940 swap(tail->destructor, head_skb->destructor);
4941 swap(tail->sk, head_skb->sk);
4942 }
4943 return segs;
4944
4945err:
4946 kfree_skb_list(segs);
4947 return ERR_PTR(err);
4948}
4949EXPORT_SYMBOL_GPL(skb_segment);
4950
4951#ifdef CONFIG_SKB_EXTENSIONS
4952#define SKB_EXT_ALIGN_VALUE 8
4953#define SKB_EXT_CHUNKSIZEOF(x) (ALIGN((sizeof(x)), SKB_EXT_ALIGN_VALUE) / SKB_EXT_ALIGN_VALUE)
4954
4955static const u8 skb_ext_type_len[] = {
4956#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
4957 [SKB_EXT_BRIDGE_NF] = SKB_EXT_CHUNKSIZEOF(struct nf_bridge_info),
4958#endif
4959#ifdef CONFIG_XFRM
4960 [SKB_EXT_SEC_PATH] = SKB_EXT_CHUNKSIZEOF(struct sec_path),
4961#endif
4962#if IS_ENABLED(CONFIG_NET_TC_SKB_EXT)
4963 [TC_SKB_EXT] = SKB_EXT_CHUNKSIZEOF(struct tc_skb_ext),
4964#endif
4965#if IS_ENABLED(CONFIG_MPTCP)
4966 [SKB_EXT_MPTCP] = SKB_EXT_CHUNKSIZEOF(struct mptcp_ext),
4967#endif
4968#if IS_ENABLED(CONFIG_MCTP_FLOWS)
4969 [SKB_EXT_MCTP] = SKB_EXT_CHUNKSIZEOF(struct mctp_flow),
4970#endif
4971};
4972
4973static __always_inline unsigned int skb_ext_total_length(void)
4974{
4975 unsigned int l = SKB_EXT_CHUNKSIZEOF(struct skb_ext);
4976 int i;
4977
4978 for (i = 0; i < ARRAY_SIZE(skb_ext_type_len); i++)
4979 l += skb_ext_type_len[i];
4980
4981 return l;
4982}
4983
4984static void skb_extensions_init(void)
4985{
4986 BUILD_BUG_ON(SKB_EXT_NUM >= 8);
4987#if !IS_ENABLED(CONFIG_KCOV_INSTRUMENT_ALL)
4988 BUILD_BUG_ON(skb_ext_total_length() > 255);
4989#endif
4990
4991 skbuff_ext_cache = kmem_cache_create("skbuff_ext_cache",
4992 SKB_EXT_ALIGN_VALUE * skb_ext_total_length(),
4993 0,
4994 SLAB_HWCACHE_ALIGN|SLAB_PANIC,
4995 NULL);
4996}
4997#else
4998static void skb_extensions_init(void) {}
4999#endif
5000
5001/* The SKB kmem_cache slab is critical for network performance. Never
5002 * merge/alias the slab with similar sized objects. This avoids fragmentation
5003 * that hurts performance of kmem_cache_{alloc,free}_bulk APIs.
5004 */
5005#ifndef CONFIG_SLUB_TINY
5006#define FLAG_SKB_NO_MERGE SLAB_NO_MERGE
5007#else /* CONFIG_SLUB_TINY - simple loop in kmem_cache_alloc_bulk */
5008#define FLAG_SKB_NO_MERGE 0
5009#endif
5010
5011void __init skb_init(void)
5012{
5013 net_hotdata.skbuff_cache = kmem_cache_create_usercopy("skbuff_head_cache",
5014 sizeof(struct sk_buff),
5015 0,
5016 SLAB_HWCACHE_ALIGN|SLAB_PANIC|
5017 FLAG_SKB_NO_MERGE,
5018 offsetof(struct sk_buff, cb),
5019 sizeof_field(struct sk_buff, cb),
5020 NULL);
5021 net_hotdata.skbuff_fclone_cache = kmem_cache_create("skbuff_fclone_cache",
5022 sizeof(struct sk_buff_fclones),
5023 0,
5024 SLAB_HWCACHE_ALIGN|SLAB_PANIC,
5025 NULL);
5026 /* usercopy should only access first SKB_SMALL_HEAD_HEADROOM bytes.
5027 * struct skb_shared_info is located at the end of skb->head,
5028 * and should not be copied to/from user.
5029 */
5030 net_hotdata.skb_small_head_cache = kmem_cache_create_usercopy("skbuff_small_head",
5031 SKB_SMALL_HEAD_CACHE_SIZE,
5032 0,
5033 SLAB_HWCACHE_ALIGN | SLAB_PANIC,
5034 0,
5035 SKB_SMALL_HEAD_HEADROOM,
5036 NULL);
5037 skb_extensions_init();
5038}
5039
5040static int
5041__skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int len,
5042 unsigned int recursion_level)
5043{
5044 int start = skb_headlen(skb);
5045 int i, copy = start - offset;
5046 struct sk_buff *frag_iter;
5047 int elt = 0;
5048
5049 if (unlikely(recursion_level >= 24))
5050 return -EMSGSIZE;
5051
5052 if (copy > 0) {
5053 if (copy > len)
5054 copy = len;
5055 sg_set_buf(sg, skb->data + offset, copy);
5056 elt++;
5057 if ((len -= copy) == 0)
5058 return elt;
5059 offset += copy;
5060 }
5061
5062 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
5063 int end;
5064
5065 WARN_ON(start > offset + len);
5066
5067 end = start + skb_frag_size(&skb_shinfo(skb)->frags[i]);
5068 if ((copy = end - offset) > 0) {
5069 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
5070 if (unlikely(elt && sg_is_last(&sg[elt - 1])))
5071 return -EMSGSIZE;
5072
5073 if (copy > len)
5074 copy = len;
5075 sg_set_page(&sg[elt], skb_frag_page(frag), copy,
5076 skb_frag_off(frag) + offset - start);
5077 elt++;
5078 if (!(len -= copy))
5079 return elt;
5080 offset += copy;
5081 }
5082 start = end;
5083 }
5084
5085 skb_walk_frags(skb, frag_iter) {
5086 int end, ret;
5087
5088 WARN_ON(start > offset + len);
5089
5090 end = start + frag_iter->len;
5091 if ((copy = end - offset) > 0) {
5092 if (unlikely(elt && sg_is_last(&sg[elt - 1])))
5093 return -EMSGSIZE;
5094
5095 if (copy > len)
5096 copy = len;
5097 ret = __skb_to_sgvec(frag_iter, sg+elt, offset - start,
5098 copy, recursion_level + 1);
5099 if (unlikely(ret < 0))
5100 return ret;
5101 elt += ret;
5102 if ((len -= copy) == 0)
5103 return elt;
5104 offset += copy;
5105 }
5106 start = end;
5107 }
5108 BUG_ON(len);
5109 return elt;
5110}
5111
5112/**
5113 * skb_to_sgvec - Fill a scatter-gather list from a socket buffer
5114 * @skb: Socket buffer containing the buffers to be mapped
5115 * @sg: The scatter-gather list to map into
5116 * @offset: The offset into the buffer's contents to start mapping
5117 * @len: Length of buffer space to be mapped
5118 *
5119 * Fill the specified scatter-gather list with mappings/pointers into a
5120 * region of the buffer space attached to a socket buffer. Returns either
5121 * the number of scatterlist items used, or -EMSGSIZE if the contents
5122 * could not fit.
5123 */
5124int skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int len)
5125{
5126 int nsg = __skb_to_sgvec(skb, sg, offset, len, 0);
5127
5128 if (nsg <= 0)
5129 return nsg;
5130
5131 sg_mark_end(&sg[nsg - 1]);
5132
5133 return nsg;
5134}
5135EXPORT_SYMBOL_GPL(skb_to_sgvec);
5136
5137/* As compared with skb_to_sgvec, skb_to_sgvec_nomark only map skb to given
5138 * sglist without mark the sg which contain last skb data as the end.
5139 * So the caller can mannipulate sg list as will when padding new data after
5140 * the first call without calling sg_unmark_end to expend sg list.
5141 *
5142 * Scenario to use skb_to_sgvec_nomark:
5143 * 1. sg_init_table
5144 * 2. skb_to_sgvec_nomark(payload1)
5145 * 3. skb_to_sgvec_nomark(payload2)
5146 *
5147 * This is equivalent to:
5148 * 1. sg_init_table
5149 * 2. skb_to_sgvec(payload1)
5150 * 3. sg_unmark_end
5151 * 4. skb_to_sgvec(payload2)
5152 *
5153 * When mapping mutilple payload conditionally, skb_to_sgvec_nomark
5154 * is more preferable.
5155 */
5156int skb_to_sgvec_nomark(struct sk_buff *skb, struct scatterlist *sg,
5157 int offset, int len)
5158{
5159 return __skb_to_sgvec(skb, sg, offset, len, 0);
5160}
5161EXPORT_SYMBOL_GPL(skb_to_sgvec_nomark);
5162
5163
5164
5165/**
5166 * skb_cow_data - Check that a socket buffer's data buffers are writable
5167 * @skb: The socket buffer to check.
5168 * @tailbits: Amount of trailing space to be added
5169 * @trailer: Returned pointer to the skb where the @tailbits space begins
5170 *
5171 * Make sure that the data buffers attached to a socket buffer are
5172 * writable. If they are not, private copies are made of the data buffers
5173 * and the socket buffer is set to use these instead.
5174 *
5175 * If @tailbits is given, make sure that there is space to write @tailbits
5176 * bytes of data beyond current end of socket buffer. @trailer will be
5177 * set to point to the skb in which this space begins.
5178 *
5179 * The number of scatterlist elements required to completely map the
5180 * COW'd and extended socket buffer will be returned.
5181 */
5182int skb_cow_data(struct sk_buff *skb, int tailbits, struct sk_buff **trailer)
5183{
5184 int copyflag;
5185 int elt;
5186 struct sk_buff *skb1, **skb_p;
5187
5188 /* If skb is cloned or its head is paged, reallocate
5189 * head pulling out all the pages (pages are considered not writable
5190 * at the moment even if they are anonymous).
5191 */
5192 if ((skb_cloned(skb) || skb_shinfo(skb)->nr_frags) &&
5193 !__pskb_pull_tail(skb, __skb_pagelen(skb)))
5194 return -ENOMEM;
5195
5196 /* Easy case. Most of packets will go this way. */
5197 if (!skb_has_frag_list(skb)) {
5198 /* A little of trouble, not enough of space for trailer.
5199 * This should not happen, when stack is tuned to generate
5200 * good frames. OK, on miss we reallocate and reserve even more
5201 * space, 128 bytes is fair. */
5202
5203 if (skb_tailroom(skb) < tailbits &&
5204 pskb_expand_head(skb, 0, tailbits-skb_tailroom(skb)+128, GFP_ATOMIC))
5205 return -ENOMEM;
5206
5207 /* Voila! */
5208 *trailer = skb;
5209 return 1;
5210 }
5211
5212 /* Misery. We are in troubles, going to mincer fragments... */
5213
5214 elt = 1;
5215 skb_p = &skb_shinfo(skb)->frag_list;
5216 copyflag = 0;
5217
5218 while ((skb1 = *skb_p) != NULL) {
5219 int ntail = 0;
5220
5221 /* The fragment is partially pulled by someone,
5222 * this can happen on input. Copy it and everything
5223 * after it. */
5224
5225 if (skb_shared(skb1))
5226 copyflag = 1;
5227
5228 /* If the skb is the last, worry about trailer. */
5229
5230 if (skb1->next == NULL && tailbits) {
5231 if (skb_shinfo(skb1)->nr_frags ||
5232 skb_has_frag_list(skb1) ||
5233 skb_tailroom(skb1) < tailbits)
5234 ntail = tailbits + 128;
5235 }
5236
5237 if (copyflag ||
5238 skb_cloned(skb1) ||
5239 ntail ||
5240 skb_shinfo(skb1)->nr_frags ||
5241 skb_has_frag_list(skb1)) {
5242 struct sk_buff *skb2;
5243
5244 /* Fuck, we are miserable poor guys... */
5245 if (ntail == 0)
5246 skb2 = skb_copy(skb1, GFP_ATOMIC);
5247 else
5248 skb2 = skb_copy_expand(skb1,
5249 skb_headroom(skb1),
5250 ntail,
5251 GFP_ATOMIC);
5252 if (unlikely(skb2 == NULL))
5253 return -ENOMEM;
5254
5255 if (skb1->sk)
5256 skb_set_owner_w(skb2, skb1->sk);
5257
5258 /* Looking around. Are we still alive?
5259 * OK, link new skb, drop old one */
5260
5261 skb2->next = skb1->next;
5262 *skb_p = skb2;
5263 kfree_skb(skb1);
5264 skb1 = skb2;
5265 }
5266 elt++;
5267 *trailer = skb1;
5268 skb_p = &skb1->next;
5269 }
5270
5271 return elt;
5272}
5273EXPORT_SYMBOL_GPL(skb_cow_data);
5274
5275static void sock_rmem_free(struct sk_buff *skb)
5276{
5277 struct sock *sk = skb->sk;
5278
5279 atomic_sub(skb->truesize, &sk->sk_rmem_alloc);
5280}
5281
5282static void skb_set_err_queue(struct sk_buff *skb)
5283{
5284 /* pkt_type of skbs received on local sockets is never PACKET_OUTGOING.
5285 * So, it is safe to (mis)use it to mark skbs on the error queue.
5286 */
5287 skb->pkt_type = PACKET_OUTGOING;
5288 BUILD_BUG_ON(PACKET_OUTGOING == 0);
5289}
5290
5291/*
5292 * Note: We dont mem charge error packets (no sk_forward_alloc changes)
5293 */
5294int sock_queue_err_skb(struct sock *sk, struct sk_buff *skb)
5295{
5296 if (atomic_read(&sk->sk_rmem_alloc) + skb->truesize >=
5297 (unsigned int)READ_ONCE(sk->sk_rcvbuf))
5298 return -ENOMEM;
5299
5300 skb_orphan(skb);
5301 skb->sk = sk;
5302 skb->destructor = sock_rmem_free;
5303 atomic_add(skb->truesize, &sk->sk_rmem_alloc);
5304 skb_set_err_queue(skb);
5305
5306 /* before exiting rcu section, make sure dst is refcounted */
5307 skb_dst_force(skb);
5308
5309 skb_queue_tail(&sk->sk_error_queue, skb);
5310 if (!sock_flag(sk, SOCK_DEAD))
5311 sk_error_report(sk);
5312 return 0;
5313}
5314EXPORT_SYMBOL(sock_queue_err_skb);
5315
5316static bool is_icmp_err_skb(const struct sk_buff *skb)
5317{
5318 return skb && (SKB_EXT_ERR(skb)->ee.ee_origin == SO_EE_ORIGIN_ICMP ||
5319 SKB_EXT_ERR(skb)->ee.ee_origin == SO_EE_ORIGIN_ICMP6);
5320}
5321
5322struct sk_buff *sock_dequeue_err_skb(struct sock *sk)
5323{
5324 struct sk_buff_head *q = &sk->sk_error_queue;
5325 struct sk_buff *skb, *skb_next = NULL;
5326 bool icmp_next = false;
5327 unsigned long flags;
5328
5329 if (skb_queue_empty_lockless(q))
5330 return NULL;
5331
5332 spin_lock_irqsave(&q->lock, flags);
5333 skb = __skb_dequeue(q);
5334 if (skb && (skb_next = skb_peek(q))) {
5335 icmp_next = is_icmp_err_skb(skb_next);
5336 if (icmp_next)
5337 sk->sk_err = SKB_EXT_ERR(skb_next)->ee.ee_errno;
5338 }
5339 spin_unlock_irqrestore(&q->lock, flags);
5340
5341 if (is_icmp_err_skb(skb) && !icmp_next)
5342 sk->sk_err = 0;
5343
5344 if (skb_next)
5345 sk_error_report(sk);
5346
5347 return skb;
5348}
5349EXPORT_SYMBOL(sock_dequeue_err_skb);
5350
5351/**
5352 * skb_clone_sk - create clone of skb, and take reference to socket
5353 * @skb: the skb to clone
5354 *
5355 * This function creates a clone of a buffer that holds a reference on
5356 * sk_refcnt. Buffers created via this function are meant to be
5357 * returned using sock_queue_err_skb, or free via kfree_skb.
5358 *
5359 * When passing buffers allocated with this function to sock_queue_err_skb
5360 * it is necessary to wrap the call with sock_hold/sock_put in order to
5361 * prevent the socket from being released prior to being enqueued on
5362 * the sk_error_queue.
5363 */
5364struct sk_buff *skb_clone_sk(struct sk_buff *skb)
5365{
5366 struct sock *sk = skb->sk;
5367 struct sk_buff *clone;
5368
5369 if (!sk || !refcount_inc_not_zero(&sk->sk_refcnt))
5370 return NULL;
5371
5372 clone = skb_clone(skb, GFP_ATOMIC);
5373 if (!clone) {
5374 sock_put(sk);
5375 return NULL;
5376 }
5377
5378 clone->sk = sk;
5379 clone->destructor = sock_efree;
5380
5381 return clone;
5382}
5383EXPORT_SYMBOL(skb_clone_sk);
5384
5385static void __skb_complete_tx_timestamp(struct sk_buff *skb,
5386 struct sock *sk,
5387 int tstype,
5388 bool opt_stats)
5389{
5390 struct sock_exterr_skb *serr;
5391 int err;
5392
5393 BUILD_BUG_ON(sizeof(struct sock_exterr_skb) > sizeof(skb->cb));
5394
5395 serr = SKB_EXT_ERR(skb);
5396 memset(serr, 0, sizeof(*serr));
5397 serr->ee.ee_errno = ENOMSG;
5398 serr->ee.ee_origin = SO_EE_ORIGIN_TIMESTAMPING;
5399 serr->ee.ee_info = tstype;
5400 serr->opt_stats = opt_stats;
5401 serr->header.h4.iif = skb->dev ? skb->dev->ifindex : 0;
5402 if (READ_ONCE(sk->sk_tsflags) & SOF_TIMESTAMPING_OPT_ID) {
5403 serr->ee.ee_data = skb_shinfo(skb)->tskey;
5404 if (sk_is_tcp(sk))
5405 serr->ee.ee_data -= atomic_read(&sk->sk_tskey);
5406 }
5407
5408 err = sock_queue_err_skb(sk, skb);
5409
5410 if (err)
5411 kfree_skb(skb);
5412}
5413
5414static bool skb_may_tx_timestamp(struct sock *sk, bool tsonly)
5415{
5416 bool ret;
5417
5418 if (likely(READ_ONCE(sysctl_tstamp_allow_data) || tsonly))
5419 return true;
5420
5421 read_lock_bh(&sk->sk_callback_lock);
5422 ret = sk->sk_socket && sk->sk_socket->file &&
5423 file_ns_capable(sk->sk_socket->file, &init_user_ns, CAP_NET_RAW);
5424 read_unlock_bh(&sk->sk_callback_lock);
5425 return ret;
5426}
5427
5428void skb_complete_tx_timestamp(struct sk_buff *skb,
5429 struct skb_shared_hwtstamps *hwtstamps)
5430{
5431 struct sock *sk = skb->sk;
5432
5433 if (!skb_may_tx_timestamp(sk, false))
5434 goto err;
5435
5436 /* Take a reference to prevent skb_orphan() from freeing the socket,
5437 * but only if the socket refcount is not zero.
5438 */
5439 if (likely(refcount_inc_not_zero(&sk->sk_refcnt))) {
5440 *skb_hwtstamps(skb) = *hwtstamps;
5441 __skb_complete_tx_timestamp(skb, sk, SCM_TSTAMP_SND, false);
5442 sock_put(sk);
5443 return;
5444 }
5445
5446err:
5447 kfree_skb(skb);
5448}
5449EXPORT_SYMBOL_GPL(skb_complete_tx_timestamp);
5450
5451void __skb_tstamp_tx(struct sk_buff *orig_skb,
5452 const struct sk_buff *ack_skb,
5453 struct skb_shared_hwtstamps *hwtstamps,
5454 struct sock *sk, int tstype)
5455{
5456 struct sk_buff *skb;
5457 bool tsonly, opt_stats = false;
5458 u32 tsflags;
5459
5460 if (!sk)
5461 return;
5462
5463 tsflags = READ_ONCE(sk->sk_tsflags);
5464 if (!hwtstamps && !(tsflags & SOF_TIMESTAMPING_OPT_TX_SWHW) &&
5465 skb_shinfo(orig_skb)->tx_flags & SKBTX_IN_PROGRESS)
5466 return;
5467
5468 tsonly = tsflags & SOF_TIMESTAMPING_OPT_TSONLY;
5469 if (!skb_may_tx_timestamp(sk, tsonly))
5470 return;
5471
5472 if (tsonly) {
5473#ifdef CONFIG_INET
5474 if ((tsflags & SOF_TIMESTAMPING_OPT_STATS) &&
5475 sk_is_tcp(sk)) {
5476 skb = tcp_get_timestamping_opt_stats(sk, orig_skb,
5477 ack_skb);
5478 opt_stats = true;
5479 } else
5480#endif
5481 skb = alloc_skb(0, GFP_ATOMIC);
5482 } else {
5483 skb = skb_clone(orig_skb, GFP_ATOMIC);
5484
5485 if (skb_orphan_frags_rx(skb, GFP_ATOMIC)) {
5486 kfree_skb(skb);
5487 return;
5488 }
5489 }
5490 if (!skb)
5491 return;
5492
5493 if (tsonly) {
5494 skb_shinfo(skb)->tx_flags |= skb_shinfo(orig_skb)->tx_flags &
5495 SKBTX_ANY_TSTAMP;
5496 skb_shinfo(skb)->tskey = skb_shinfo(orig_skb)->tskey;
5497 }
5498
5499 if (hwtstamps)
5500 *skb_hwtstamps(skb) = *hwtstamps;
5501 else
5502 __net_timestamp(skb);
5503
5504 __skb_complete_tx_timestamp(skb, sk, tstype, opt_stats);
5505}
5506EXPORT_SYMBOL_GPL(__skb_tstamp_tx);
5507
5508void skb_tstamp_tx(struct sk_buff *orig_skb,
5509 struct skb_shared_hwtstamps *hwtstamps)
5510{
5511 return __skb_tstamp_tx(orig_skb, NULL, hwtstamps, orig_skb->sk,
5512 SCM_TSTAMP_SND);
5513}
5514EXPORT_SYMBOL_GPL(skb_tstamp_tx);
5515
5516#ifdef CONFIG_WIRELESS
5517void skb_complete_wifi_ack(struct sk_buff *skb, bool acked)
5518{
5519 struct sock *sk = skb->sk;
5520 struct sock_exterr_skb *serr;
5521 int err = 1;
5522
5523 skb->wifi_acked_valid = 1;
5524 skb->wifi_acked = acked;
5525
5526 serr = SKB_EXT_ERR(skb);
5527 memset(serr, 0, sizeof(*serr));
5528 serr->ee.ee_errno = ENOMSG;
5529 serr->ee.ee_origin = SO_EE_ORIGIN_TXSTATUS;
5530
5531 /* Take a reference to prevent skb_orphan() from freeing the socket,
5532 * but only if the socket refcount is not zero.
5533 */
5534 if (likely(refcount_inc_not_zero(&sk->sk_refcnt))) {
5535 err = sock_queue_err_skb(sk, skb);
5536 sock_put(sk);
5537 }
5538 if (err)
5539 kfree_skb(skb);
5540}
5541EXPORT_SYMBOL_GPL(skb_complete_wifi_ack);
5542#endif /* CONFIG_WIRELESS */
5543
5544/**
5545 * skb_partial_csum_set - set up and verify partial csum values for packet
5546 * @skb: the skb to set
5547 * @start: the number of bytes after skb->data to start checksumming.
5548 * @off: the offset from start to place the checksum.
5549 *
5550 * For untrusted partially-checksummed packets, we need to make sure the values
5551 * for skb->csum_start and skb->csum_offset are valid so we don't oops.
5552 *
5553 * This function checks and sets those values and skb->ip_summed: if this
5554 * returns false you should drop the packet.
5555 */
5556bool skb_partial_csum_set(struct sk_buff *skb, u16 start, u16 off)
5557{
5558 u32 csum_end = (u32)start + (u32)off + sizeof(__sum16);
5559 u32 csum_start = skb_headroom(skb) + (u32)start;
5560
5561 if (unlikely(csum_start >= U16_MAX || csum_end > skb_headlen(skb))) {
5562 net_warn_ratelimited("bad partial csum: csum=%u/%u headroom=%u headlen=%u\n",
5563 start, off, skb_headroom(skb), skb_headlen(skb));
5564 return false;
5565 }
5566 skb->ip_summed = CHECKSUM_PARTIAL;
5567 skb->csum_start = csum_start;
5568 skb->csum_offset = off;
5569 skb->transport_header = csum_start;
5570 return true;
5571}
5572EXPORT_SYMBOL_GPL(skb_partial_csum_set);
5573
5574static int skb_maybe_pull_tail(struct sk_buff *skb, unsigned int len,
5575 unsigned int max)
5576{
5577 if (skb_headlen(skb) >= len)
5578 return 0;
5579
5580 /* If we need to pullup then pullup to the max, so we
5581 * won't need to do it again.
5582 */
5583 if (max > skb->len)
5584 max = skb->len;
5585
5586 if (__pskb_pull_tail(skb, max - skb_headlen(skb)) == NULL)
5587 return -ENOMEM;
5588
5589 if (skb_headlen(skb) < len)
5590 return -EPROTO;
5591
5592 return 0;
5593}
5594
5595#define MAX_TCP_HDR_LEN (15 * 4)
5596
5597static __sum16 *skb_checksum_setup_ip(struct sk_buff *skb,
5598 typeof(IPPROTO_IP) proto,
5599 unsigned int off)
5600{
5601 int err;
5602
5603 switch (proto) {
5604 case IPPROTO_TCP:
5605 err = skb_maybe_pull_tail(skb, off + sizeof(struct tcphdr),
5606 off + MAX_TCP_HDR_LEN);
5607 if (!err && !skb_partial_csum_set(skb, off,
5608 offsetof(struct tcphdr,
5609 check)))
5610 err = -EPROTO;
5611 return err ? ERR_PTR(err) : &tcp_hdr(skb)->check;
5612
5613 case IPPROTO_UDP:
5614 err = skb_maybe_pull_tail(skb, off + sizeof(struct udphdr),
5615 off + sizeof(struct udphdr));
5616 if (!err && !skb_partial_csum_set(skb, off,
5617 offsetof(struct udphdr,
5618 check)))
5619 err = -EPROTO;
5620 return err ? ERR_PTR(err) : &udp_hdr(skb)->check;
5621 }
5622
5623 return ERR_PTR(-EPROTO);
5624}
5625
5626/* This value should be large enough to cover a tagged ethernet header plus
5627 * maximally sized IP and TCP or UDP headers.
5628 */
5629#define MAX_IP_HDR_LEN 128
5630
5631static int skb_checksum_setup_ipv4(struct sk_buff *skb, bool recalculate)
5632{
5633 unsigned int off;
5634 bool fragment;
5635 __sum16 *csum;
5636 int err;
5637
5638 fragment = false;
5639
5640 err = skb_maybe_pull_tail(skb,
5641 sizeof(struct iphdr),
5642 MAX_IP_HDR_LEN);
5643 if (err < 0)
5644 goto out;
5645
5646 if (ip_is_fragment(ip_hdr(skb)))
5647 fragment = true;
5648
5649 off = ip_hdrlen(skb);
5650
5651 err = -EPROTO;
5652
5653 if (fragment)
5654 goto out;
5655
5656 csum = skb_checksum_setup_ip(skb, ip_hdr(skb)->protocol, off);
5657 if (IS_ERR(csum))
5658 return PTR_ERR(csum);
5659
5660 if (recalculate)
5661 *csum = ~csum_tcpudp_magic(ip_hdr(skb)->saddr,
5662 ip_hdr(skb)->daddr,
5663 skb->len - off,
5664 ip_hdr(skb)->protocol, 0);
5665 err = 0;
5666
5667out:
5668 return err;
5669}
5670
5671/* This value should be large enough to cover a tagged ethernet header plus
5672 * an IPv6 header, all options, and a maximal TCP or UDP header.
5673 */
5674#define MAX_IPV6_HDR_LEN 256
5675
5676#define OPT_HDR(type, skb, off) \
5677 (type *)(skb_network_header(skb) + (off))
5678
5679static int skb_checksum_setup_ipv6(struct sk_buff *skb, bool recalculate)
5680{
5681 int err;
5682 u8 nexthdr;
5683 unsigned int off;
5684 unsigned int len;
5685 bool fragment;
5686 bool done;
5687 __sum16 *csum;
5688
5689 fragment = false;
5690 done = false;
5691
5692 off = sizeof(struct ipv6hdr);
5693
5694 err = skb_maybe_pull_tail(skb, off, MAX_IPV6_HDR_LEN);
5695 if (err < 0)
5696 goto out;
5697
5698 nexthdr = ipv6_hdr(skb)->nexthdr;
5699
5700 len = sizeof(struct ipv6hdr) + ntohs(ipv6_hdr(skb)->payload_len);
5701 while (off <= len && !done) {
5702 switch (nexthdr) {
5703 case IPPROTO_DSTOPTS:
5704 case IPPROTO_HOPOPTS:
5705 case IPPROTO_ROUTING: {
5706 struct ipv6_opt_hdr *hp;
5707
5708 err = skb_maybe_pull_tail(skb,
5709 off +
5710 sizeof(struct ipv6_opt_hdr),
5711 MAX_IPV6_HDR_LEN);
5712 if (err < 0)
5713 goto out;
5714
5715 hp = OPT_HDR(struct ipv6_opt_hdr, skb, off);
5716 nexthdr = hp->nexthdr;
5717 off += ipv6_optlen(hp);
5718 break;
5719 }
5720 case IPPROTO_AH: {
5721 struct ip_auth_hdr *hp;
5722
5723 err = skb_maybe_pull_tail(skb,
5724 off +
5725 sizeof(struct ip_auth_hdr),
5726 MAX_IPV6_HDR_LEN);
5727 if (err < 0)
5728 goto out;
5729
5730 hp = OPT_HDR(struct ip_auth_hdr, skb, off);
5731 nexthdr = hp->nexthdr;
5732 off += ipv6_authlen(hp);
5733 break;
5734 }
5735 case IPPROTO_FRAGMENT: {
5736 struct frag_hdr *hp;
5737
5738 err = skb_maybe_pull_tail(skb,
5739 off +
5740 sizeof(struct frag_hdr),
5741 MAX_IPV6_HDR_LEN);
5742 if (err < 0)
5743 goto out;
5744
5745 hp = OPT_HDR(struct frag_hdr, skb, off);
5746
5747 if (hp->frag_off & htons(IP6_OFFSET | IP6_MF))
5748 fragment = true;
5749
5750 nexthdr = hp->nexthdr;
5751 off += sizeof(struct frag_hdr);
5752 break;
5753 }
5754 default:
5755 done = true;
5756 break;
5757 }
5758 }
5759
5760 err = -EPROTO;
5761
5762 if (!done || fragment)
5763 goto out;
5764
5765 csum = skb_checksum_setup_ip(skb, nexthdr, off);
5766 if (IS_ERR(csum))
5767 return PTR_ERR(csum);
5768
5769 if (recalculate)
5770 *csum = ~csum_ipv6_magic(&ipv6_hdr(skb)->saddr,
5771 &ipv6_hdr(skb)->daddr,
5772 skb->len - off, nexthdr, 0);
5773 err = 0;
5774
5775out:
5776 return err;
5777}
5778
5779/**
5780 * skb_checksum_setup - set up partial checksum offset
5781 * @skb: the skb to set up
5782 * @recalculate: if true the pseudo-header checksum will be recalculated
5783 */
5784int skb_checksum_setup(struct sk_buff *skb, bool recalculate)
5785{
5786 int err;
5787
5788 switch (skb->protocol) {
5789 case htons(ETH_P_IP):
5790 err = skb_checksum_setup_ipv4(skb, recalculate);
5791 break;
5792
5793 case htons(ETH_P_IPV6):
5794 err = skb_checksum_setup_ipv6(skb, recalculate);
5795 break;
5796
5797 default:
5798 err = -EPROTO;
5799 break;
5800 }
5801
5802 return err;
5803}
5804EXPORT_SYMBOL(skb_checksum_setup);
5805
5806/**
5807 * skb_checksum_maybe_trim - maybe trims the given skb
5808 * @skb: the skb to check
5809 * @transport_len: the data length beyond the network header
5810 *
5811 * Checks whether the given skb has data beyond the given transport length.
5812 * If so, returns a cloned skb trimmed to this transport length.
5813 * Otherwise returns the provided skb. Returns NULL in error cases
5814 * (e.g. transport_len exceeds skb length or out-of-memory).
5815 *
5816 * Caller needs to set the skb transport header and free any returned skb if it
5817 * differs from the provided skb.
5818 */
5819static struct sk_buff *skb_checksum_maybe_trim(struct sk_buff *skb,
5820 unsigned int transport_len)
5821{
5822 struct sk_buff *skb_chk;
5823 unsigned int len = skb_transport_offset(skb) + transport_len;
5824 int ret;
5825
5826 if (skb->len < len)
5827 return NULL;
5828 else if (skb->len == len)
5829 return skb;
5830
5831 skb_chk = skb_clone(skb, GFP_ATOMIC);
5832 if (!skb_chk)
5833 return NULL;
5834
5835 ret = pskb_trim_rcsum(skb_chk, len);
5836 if (ret) {
5837 kfree_skb(skb_chk);
5838 return NULL;
5839 }
5840
5841 return skb_chk;
5842}
5843
5844/**
5845 * skb_checksum_trimmed - validate checksum of an skb
5846 * @skb: the skb to check
5847 * @transport_len: the data length beyond the network header
5848 * @skb_chkf: checksum function to use
5849 *
5850 * Applies the given checksum function skb_chkf to the provided skb.
5851 * Returns a checked and maybe trimmed skb. Returns NULL on error.
5852 *
5853 * If the skb has data beyond the given transport length, then a
5854 * trimmed & cloned skb is checked and returned.
5855 *
5856 * Caller needs to set the skb transport header and free any returned skb if it
5857 * differs from the provided skb.
5858 */
5859struct sk_buff *skb_checksum_trimmed(struct sk_buff *skb,
5860 unsigned int transport_len,
5861 __sum16(*skb_chkf)(struct sk_buff *skb))
5862{
5863 struct sk_buff *skb_chk;
5864 unsigned int offset = skb_transport_offset(skb);
5865 __sum16 ret;
5866
5867 skb_chk = skb_checksum_maybe_trim(skb, transport_len);
5868 if (!skb_chk)
5869 goto err;
5870
5871 if (!pskb_may_pull(skb_chk, offset))
5872 goto err;
5873
5874 skb_pull_rcsum(skb_chk, offset);
5875 ret = skb_chkf(skb_chk);
5876 skb_push_rcsum(skb_chk, offset);
5877
5878 if (ret)
5879 goto err;
5880
5881 return skb_chk;
5882
5883err:
5884 if (skb_chk && skb_chk != skb)
5885 kfree_skb(skb_chk);
5886
5887 return NULL;
5888
5889}
5890EXPORT_SYMBOL(skb_checksum_trimmed);
5891
5892void __skb_warn_lro_forwarding(const struct sk_buff *skb)
5893{
5894 net_warn_ratelimited("%s: received packets cannot be forwarded while LRO is enabled\n",
5895 skb->dev->name);
5896}
5897EXPORT_SYMBOL(__skb_warn_lro_forwarding);
5898
5899void kfree_skb_partial(struct sk_buff *skb, bool head_stolen)
5900{
5901 if (head_stolen) {
5902 skb_release_head_state(skb);
5903 kmem_cache_free(net_hotdata.skbuff_cache, skb);
5904 } else {
5905 __kfree_skb(skb);
5906 }
5907}
5908EXPORT_SYMBOL(kfree_skb_partial);
5909
5910/**
5911 * skb_try_coalesce - try to merge skb to prior one
5912 * @to: prior buffer
5913 * @from: buffer to add
5914 * @fragstolen: pointer to boolean
5915 * @delta_truesize: how much more was allocated than was requested
5916 */
5917bool skb_try_coalesce(struct sk_buff *to, struct sk_buff *from,
5918 bool *fragstolen, int *delta_truesize)
5919{
5920 struct skb_shared_info *to_shinfo, *from_shinfo;
5921 int i, delta, len = from->len;
5922
5923 *fragstolen = false;
5924
5925 if (skb_cloned(to))
5926 return false;
5927
5928 /* In general, avoid mixing page_pool and non-page_pool allocated
5929 * pages within the same SKB. In theory we could take full
5930 * references if @from is cloned and !@to->pp_recycle but its
5931 * tricky (due to potential race with the clone disappearing) and
5932 * rare, so not worth dealing with.
5933 */
5934 if (to->pp_recycle != from->pp_recycle)
5935 return false;
5936
5937 if (len <= skb_tailroom(to)) {
5938 if (len)
5939 BUG_ON(skb_copy_bits(from, 0, skb_put(to, len), len));
5940 *delta_truesize = 0;
5941 return true;
5942 }
5943
5944 to_shinfo = skb_shinfo(to);
5945 from_shinfo = skb_shinfo(from);
5946 if (to_shinfo->frag_list || from_shinfo->frag_list)
5947 return false;
5948 if (skb_zcopy(to) || skb_zcopy(from))
5949 return false;
5950
5951 if (skb_headlen(from) != 0) {
5952 struct page *page;
5953 unsigned int offset;
5954
5955 if (to_shinfo->nr_frags +
5956 from_shinfo->nr_frags >= MAX_SKB_FRAGS)
5957 return false;
5958
5959 if (skb_head_is_locked(from))
5960 return false;
5961
5962 delta = from->truesize - SKB_DATA_ALIGN(sizeof(struct sk_buff));
5963
5964 page = virt_to_head_page(from->head);
5965 offset = from->data - (unsigned char *)page_address(page);
5966
5967 skb_fill_page_desc(to, to_shinfo->nr_frags,
5968 page, offset, skb_headlen(from));
5969 *fragstolen = true;
5970 } else {
5971 if (to_shinfo->nr_frags +
5972 from_shinfo->nr_frags > MAX_SKB_FRAGS)
5973 return false;
5974
5975 delta = from->truesize - SKB_TRUESIZE(skb_end_offset(from));
5976 }
5977
5978 WARN_ON_ONCE(delta < len);
5979
5980 memcpy(to_shinfo->frags + to_shinfo->nr_frags,
5981 from_shinfo->frags,
5982 from_shinfo->nr_frags * sizeof(skb_frag_t));
5983 to_shinfo->nr_frags += from_shinfo->nr_frags;
5984
5985 if (!skb_cloned(from))
5986 from_shinfo->nr_frags = 0;
5987
5988 /* if the skb is not cloned this does nothing
5989 * since we set nr_frags to 0.
5990 */
5991 if (skb_pp_frag_ref(from)) {
5992 for (i = 0; i < from_shinfo->nr_frags; i++)
5993 __skb_frag_ref(&from_shinfo->frags[i]);
5994 }
5995
5996 to->truesize += delta;
5997 to->len += len;
5998 to->data_len += len;
5999
6000 *delta_truesize = delta;
6001 return true;
6002}
6003EXPORT_SYMBOL(skb_try_coalesce);
6004
6005/**
6006 * skb_scrub_packet - scrub an skb
6007 *
6008 * @skb: buffer to clean
6009 * @xnet: packet is crossing netns
6010 *
6011 * skb_scrub_packet can be used after encapsulating or decapsulting a packet
6012 * into/from a tunnel. Some information have to be cleared during these
6013 * operations.
6014 * skb_scrub_packet can also be used to clean a skb before injecting it in
6015 * another namespace (@xnet == true). We have to clear all information in the
6016 * skb that could impact namespace isolation.
6017 */
6018void skb_scrub_packet(struct sk_buff *skb, bool xnet)
6019{
6020 skb->pkt_type = PACKET_HOST;
6021 skb->skb_iif = 0;
6022 skb->ignore_df = 0;
6023 skb_dst_drop(skb);
6024 skb_ext_reset(skb);
6025 nf_reset_ct(skb);
6026 nf_reset_trace(skb);
6027
6028#ifdef CONFIG_NET_SWITCHDEV
6029 skb->offload_fwd_mark = 0;
6030 skb->offload_l3_fwd_mark = 0;
6031#endif
6032
6033 if (!xnet)
6034 return;
6035
6036 ipvs_reset(skb);
6037 skb->mark = 0;
6038 skb_clear_tstamp(skb);
6039}
6040EXPORT_SYMBOL_GPL(skb_scrub_packet);
6041
6042static struct sk_buff *skb_reorder_vlan_header(struct sk_buff *skb)
6043{
6044 int mac_len, meta_len;
6045 void *meta;
6046
6047 if (skb_cow(skb, skb_headroom(skb)) < 0) {
6048 kfree_skb(skb);
6049 return NULL;
6050 }
6051
6052 mac_len = skb->data - skb_mac_header(skb);
6053 if (likely(mac_len > VLAN_HLEN + ETH_TLEN)) {
6054 memmove(skb_mac_header(skb) + VLAN_HLEN, skb_mac_header(skb),
6055 mac_len - VLAN_HLEN - ETH_TLEN);
6056 }
6057
6058 meta_len = skb_metadata_len(skb);
6059 if (meta_len) {
6060 meta = skb_metadata_end(skb) - meta_len;
6061 memmove(meta + VLAN_HLEN, meta, meta_len);
6062 }
6063
6064 skb->mac_header += VLAN_HLEN;
6065 return skb;
6066}
6067
6068struct sk_buff *skb_vlan_untag(struct sk_buff *skb)
6069{
6070 struct vlan_hdr *vhdr;
6071 u16 vlan_tci;
6072
6073 if (unlikely(skb_vlan_tag_present(skb))) {
6074 /* vlan_tci is already set-up so leave this for another time */
6075 return skb;
6076 }
6077
6078 skb = skb_share_check(skb, GFP_ATOMIC);
6079 if (unlikely(!skb))
6080 goto err_free;
6081 /* We may access the two bytes after vlan_hdr in vlan_set_encap_proto(). */
6082 if (unlikely(!pskb_may_pull(skb, VLAN_HLEN + sizeof(unsigned short))))
6083 goto err_free;
6084
6085 vhdr = (struct vlan_hdr *)skb->data;
6086 vlan_tci = ntohs(vhdr->h_vlan_TCI);
6087 __vlan_hwaccel_put_tag(skb, skb->protocol, vlan_tci);
6088
6089 skb_pull_rcsum(skb, VLAN_HLEN);
6090 vlan_set_encap_proto(skb, vhdr);
6091
6092 skb = skb_reorder_vlan_header(skb);
6093 if (unlikely(!skb))
6094 goto err_free;
6095
6096 skb_reset_network_header(skb);
6097 if (!skb_transport_header_was_set(skb))
6098 skb_reset_transport_header(skb);
6099 skb_reset_mac_len(skb);
6100
6101 return skb;
6102
6103err_free:
6104 kfree_skb(skb);
6105 return NULL;
6106}
6107EXPORT_SYMBOL(skb_vlan_untag);
6108
6109int skb_ensure_writable(struct sk_buff *skb, unsigned int write_len)
6110{
6111 if (!pskb_may_pull(skb, write_len))
6112 return -ENOMEM;
6113
6114 if (!skb_cloned(skb) || skb_clone_writable(skb, write_len))
6115 return 0;
6116
6117 return pskb_expand_head(skb, 0, 0, GFP_ATOMIC);
6118}
6119EXPORT_SYMBOL(skb_ensure_writable);
6120
6121int skb_ensure_writable_head_tail(struct sk_buff *skb, struct net_device *dev)
6122{
6123 int needed_headroom = dev->needed_headroom;
6124 int needed_tailroom = dev->needed_tailroom;
6125
6126 /* For tail taggers, we need to pad short frames ourselves, to ensure
6127 * that the tail tag does not fail at its role of being at the end of
6128 * the packet, once the conduit interface pads the frame. Account for
6129 * that pad length here, and pad later.
6130 */
6131 if (unlikely(needed_tailroom && skb->len < ETH_ZLEN))
6132 needed_tailroom += ETH_ZLEN - skb->len;
6133 /* skb_headroom() returns unsigned int... */
6134 needed_headroom = max_t(int, needed_headroom - skb_headroom(skb), 0);
6135 needed_tailroom = max_t(int, needed_tailroom - skb_tailroom(skb), 0);
6136
6137 if (likely(!needed_headroom && !needed_tailroom && !skb_cloned(skb)))
6138 /* No reallocation needed, yay! */
6139 return 0;
6140
6141 return pskb_expand_head(skb, needed_headroom, needed_tailroom,
6142 GFP_ATOMIC);
6143}
6144EXPORT_SYMBOL(skb_ensure_writable_head_tail);
6145
6146/* remove VLAN header from packet and update csum accordingly.
6147 * expects a non skb_vlan_tag_present skb with a vlan tag payload
6148 */
6149int __skb_vlan_pop(struct sk_buff *skb, u16 *vlan_tci)
6150{
6151 int offset = skb->data - skb_mac_header(skb);
6152 int err;
6153
6154 if (WARN_ONCE(offset,
6155 "__skb_vlan_pop got skb with skb->data not at mac header (offset %d)\n",
6156 offset)) {
6157 return -EINVAL;
6158 }
6159
6160 err = skb_ensure_writable(skb, VLAN_ETH_HLEN);
6161 if (unlikely(err))
6162 return err;
6163
6164 skb_postpull_rcsum(skb, skb->data + (2 * ETH_ALEN), VLAN_HLEN);
6165
6166 vlan_remove_tag(skb, vlan_tci);
6167
6168 skb->mac_header += VLAN_HLEN;
6169
6170 if (skb_network_offset(skb) < ETH_HLEN)
6171 skb_set_network_header(skb, ETH_HLEN);
6172
6173 skb_reset_mac_len(skb);
6174
6175 return err;
6176}
6177EXPORT_SYMBOL(__skb_vlan_pop);
6178
6179/* Pop a vlan tag either from hwaccel or from payload.
6180 * Expects skb->data at mac header.
6181 */
6182int skb_vlan_pop(struct sk_buff *skb)
6183{
6184 u16 vlan_tci;
6185 __be16 vlan_proto;
6186 int err;
6187
6188 if (likely(skb_vlan_tag_present(skb))) {
6189 __vlan_hwaccel_clear_tag(skb);
6190 } else {
6191 if (unlikely(!eth_type_vlan(skb->protocol)))
6192 return 0;
6193
6194 err = __skb_vlan_pop(skb, &vlan_tci);
6195 if (err)
6196 return err;
6197 }
6198 /* move next vlan tag to hw accel tag */
6199 if (likely(!eth_type_vlan(skb->protocol)))
6200 return 0;
6201
6202 vlan_proto = skb->protocol;
6203 err = __skb_vlan_pop(skb, &vlan_tci);
6204 if (unlikely(err))
6205 return err;
6206
6207 __vlan_hwaccel_put_tag(skb, vlan_proto, vlan_tci);
6208 return 0;
6209}
6210EXPORT_SYMBOL(skb_vlan_pop);
6211
6212/* Push a vlan tag either into hwaccel or into payload (if hwaccel tag present).
6213 * Expects skb->data at mac header.
6214 */
6215int skb_vlan_push(struct sk_buff *skb, __be16 vlan_proto, u16 vlan_tci)
6216{
6217 if (skb_vlan_tag_present(skb)) {
6218 int offset = skb->data - skb_mac_header(skb);
6219 int err;
6220
6221 if (WARN_ONCE(offset,
6222 "skb_vlan_push got skb with skb->data not at mac header (offset %d)\n",
6223 offset)) {
6224 return -EINVAL;
6225 }
6226
6227 err = __vlan_insert_tag(skb, skb->vlan_proto,
6228 skb_vlan_tag_get(skb));
6229 if (err)
6230 return err;
6231
6232 skb->protocol = skb->vlan_proto;
6233 skb->mac_len += VLAN_HLEN;
6234
6235 skb_postpush_rcsum(skb, skb->data + (2 * ETH_ALEN), VLAN_HLEN);
6236 }
6237 __vlan_hwaccel_put_tag(skb, vlan_proto, vlan_tci);
6238 return 0;
6239}
6240EXPORT_SYMBOL(skb_vlan_push);
6241
6242/**
6243 * skb_eth_pop() - Drop the Ethernet header at the head of a packet
6244 *
6245 * @skb: Socket buffer to modify
6246 *
6247 * Drop the Ethernet header of @skb.
6248 *
6249 * Expects that skb->data points to the mac header and that no VLAN tags are
6250 * present.
6251 *
6252 * Returns 0 on success, -errno otherwise.
6253 */
6254int skb_eth_pop(struct sk_buff *skb)
6255{
6256 if (!pskb_may_pull(skb, ETH_HLEN) || skb_vlan_tagged(skb) ||
6257 skb_network_offset(skb) < ETH_HLEN)
6258 return -EPROTO;
6259
6260 skb_pull_rcsum(skb, ETH_HLEN);
6261 skb_reset_mac_header(skb);
6262 skb_reset_mac_len(skb);
6263
6264 return 0;
6265}
6266EXPORT_SYMBOL(skb_eth_pop);
6267
6268/**
6269 * skb_eth_push() - Add a new Ethernet header at the head of a packet
6270 *
6271 * @skb: Socket buffer to modify
6272 * @dst: Destination MAC address of the new header
6273 * @src: Source MAC address of the new header
6274 *
6275 * Prepend @skb with a new Ethernet header.
6276 *
6277 * Expects that skb->data points to the mac header, which must be empty.
6278 *
6279 * Returns 0 on success, -errno otherwise.
6280 */
6281int skb_eth_push(struct sk_buff *skb, const unsigned char *dst,
6282 const unsigned char *src)
6283{
6284 struct ethhdr *eth;
6285 int err;
6286
6287 if (skb_network_offset(skb) || skb_vlan_tag_present(skb))
6288 return -EPROTO;
6289
6290 err = skb_cow_head(skb, sizeof(*eth));
6291 if (err < 0)
6292 return err;
6293
6294 skb_push(skb, sizeof(*eth));
6295 skb_reset_mac_header(skb);
6296 skb_reset_mac_len(skb);
6297
6298 eth = eth_hdr(skb);
6299 ether_addr_copy(eth->h_dest, dst);
6300 ether_addr_copy(eth->h_source, src);
6301 eth->h_proto = skb->protocol;
6302
6303 skb_postpush_rcsum(skb, eth, sizeof(*eth));
6304
6305 return 0;
6306}
6307EXPORT_SYMBOL(skb_eth_push);
6308
6309/* Update the ethertype of hdr and the skb csum value if required. */
6310static void skb_mod_eth_type(struct sk_buff *skb, struct ethhdr *hdr,
6311 __be16 ethertype)
6312{
6313 if (skb->ip_summed == CHECKSUM_COMPLETE) {
6314 __be16 diff[] = { ~hdr->h_proto, ethertype };
6315
6316 skb->csum = csum_partial((char *)diff, sizeof(diff), skb->csum);
6317 }
6318
6319 hdr->h_proto = ethertype;
6320}
6321
6322/**
6323 * skb_mpls_push() - push a new MPLS header after mac_len bytes from start of
6324 * the packet
6325 *
6326 * @skb: buffer
6327 * @mpls_lse: MPLS label stack entry to push
6328 * @mpls_proto: ethertype of the new MPLS header (expects 0x8847 or 0x8848)
6329 * @mac_len: length of the MAC header
6330 * @ethernet: flag to indicate if the resulting packet after skb_mpls_push is
6331 * ethernet
6332 *
6333 * Expects skb->data at mac header.
6334 *
6335 * Returns 0 on success, -errno otherwise.
6336 */
6337int skb_mpls_push(struct sk_buff *skb, __be32 mpls_lse, __be16 mpls_proto,
6338 int mac_len, bool ethernet)
6339{
6340 struct mpls_shim_hdr *lse;
6341 int err;
6342
6343 if (unlikely(!eth_p_mpls(mpls_proto)))
6344 return -EINVAL;
6345
6346 /* Networking stack does not allow simultaneous Tunnel and MPLS GSO. */
6347 if (skb->encapsulation)
6348 return -EINVAL;
6349
6350 err = skb_cow_head(skb, MPLS_HLEN);
6351 if (unlikely(err))
6352 return err;
6353
6354 if (!skb->inner_protocol) {
6355 skb_set_inner_network_header(skb, skb_network_offset(skb));
6356 skb_set_inner_protocol(skb, skb->protocol);
6357 }
6358
6359 skb_push(skb, MPLS_HLEN);
6360 memmove(skb_mac_header(skb) - MPLS_HLEN, skb_mac_header(skb),
6361 mac_len);
6362 skb_reset_mac_header(skb);
6363 skb_set_network_header(skb, mac_len);
6364 skb_reset_mac_len(skb);
6365
6366 lse = mpls_hdr(skb);
6367 lse->label_stack_entry = mpls_lse;
6368 skb_postpush_rcsum(skb, lse, MPLS_HLEN);
6369
6370 if (ethernet && mac_len >= ETH_HLEN)
6371 skb_mod_eth_type(skb, eth_hdr(skb), mpls_proto);
6372 skb->protocol = mpls_proto;
6373
6374 return 0;
6375}
6376EXPORT_SYMBOL_GPL(skb_mpls_push);
6377
6378/**
6379 * skb_mpls_pop() - pop the outermost MPLS header
6380 *
6381 * @skb: buffer
6382 * @next_proto: ethertype of header after popped MPLS header
6383 * @mac_len: length of the MAC header
6384 * @ethernet: flag to indicate if the packet is ethernet
6385 *
6386 * Expects skb->data at mac header.
6387 *
6388 * Returns 0 on success, -errno otherwise.
6389 */
6390int skb_mpls_pop(struct sk_buff *skb, __be16 next_proto, int mac_len,
6391 bool ethernet)
6392{
6393 int err;
6394
6395 if (unlikely(!eth_p_mpls(skb->protocol)))
6396 return 0;
6397
6398 err = skb_ensure_writable(skb, mac_len + MPLS_HLEN);
6399 if (unlikely(err))
6400 return err;
6401
6402 skb_postpull_rcsum(skb, mpls_hdr(skb), MPLS_HLEN);
6403 memmove(skb_mac_header(skb) + MPLS_HLEN, skb_mac_header(skb),
6404 mac_len);
6405
6406 __skb_pull(skb, MPLS_HLEN);
6407 skb_reset_mac_header(skb);
6408 skb_set_network_header(skb, mac_len);
6409
6410 if (ethernet && mac_len >= ETH_HLEN) {
6411 struct ethhdr *hdr;
6412
6413 /* use mpls_hdr() to get ethertype to account for VLANs. */
6414 hdr = (struct ethhdr *)((void *)mpls_hdr(skb) - ETH_HLEN);
6415 skb_mod_eth_type(skb, hdr, next_proto);
6416 }
6417 skb->protocol = next_proto;
6418
6419 return 0;
6420}
6421EXPORT_SYMBOL_GPL(skb_mpls_pop);
6422
6423/**
6424 * skb_mpls_update_lse() - modify outermost MPLS header and update csum
6425 *
6426 * @skb: buffer
6427 * @mpls_lse: new MPLS label stack entry to update to
6428 *
6429 * Expects skb->data at mac header.
6430 *
6431 * Returns 0 on success, -errno otherwise.
6432 */
6433int skb_mpls_update_lse(struct sk_buff *skb, __be32 mpls_lse)
6434{
6435 int err;
6436
6437 if (unlikely(!eth_p_mpls(skb->protocol)))
6438 return -EINVAL;
6439
6440 err = skb_ensure_writable(skb, skb->mac_len + MPLS_HLEN);
6441 if (unlikely(err))
6442 return err;
6443
6444 if (skb->ip_summed == CHECKSUM_COMPLETE) {
6445 __be32 diff[] = { ~mpls_hdr(skb)->label_stack_entry, mpls_lse };
6446
6447 skb->csum = csum_partial((char *)diff, sizeof(diff), skb->csum);
6448 }
6449
6450 mpls_hdr(skb)->label_stack_entry = mpls_lse;
6451
6452 return 0;
6453}
6454EXPORT_SYMBOL_GPL(skb_mpls_update_lse);
6455
6456/**
6457 * skb_mpls_dec_ttl() - decrement the TTL of the outermost MPLS header
6458 *
6459 * @skb: buffer
6460 *
6461 * Expects skb->data at mac header.
6462 *
6463 * Returns 0 on success, -errno otherwise.
6464 */
6465int skb_mpls_dec_ttl(struct sk_buff *skb)
6466{
6467 u32 lse;
6468 u8 ttl;
6469
6470 if (unlikely(!eth_p_mpls(skb->protocol)))
6471 return -EINVAL;
6472
6473 if (!pskb_may_pull(skb, skb_network_offset(skb) + MPLS_HLEN))
6474 return -ENOMEM;
6475
6476 lse = be32_to_cpu(mpls_hdr(skb)->label_stack_entry);
6477 ttl = (lse & MPLS_LS_TTL_MASK) >> MPLS_LS_TTL_SHIFT;
6478 if (!--ttl)
6479 return -EINVAL;
6480
6481 lse &= ~MPLS_LS_TTL_MASK;
6482 lse |= ttl << MPLS_LS_TTL_SHIFT;
6483
6484 return skb_mpls_update_lse(skb, cpu_to_be32(lse));
6485}
6486EXPORT_SYMBOL_GPL(skb_mpls_dec_ttl);
6487
6488/**
6489 * alloc_skb_with_frags - allocate skb with page frags
6490 *
6491 * @header_len: size of linear part
6492 * @data_len: needed length in frags
6493 * @order: max page order desired.
6494 * @errcode: pointer to error code if any
6495 * @gfp_mask: allocation mask
6496 *
6497 * This can be used to allocate a paged skb, given a maximal order for frags.
6498 */
6499struct sk_buff *alloc_skb_with_frags(unsigned long header_len,
6500 unsigned long data_len,
6501 int order,
6502 int *errcode,
6503 gfp_t gfp_mask)
6504{
6505 unsigned long chunk;
6506 struct sk_buff *skb;
6507 struct page *page;
6508 int nr_frags = 0;
6509
6510 *errcode = -EMSGSIZE;
6511 if (unlikely(data_len > MAX_SKB_FRAGS * (PAGE_SIZE << order)))
6512 return NULL;
6513
6514 *errcode = -ENOBUFS;
6515 skb = alloc_skb(header_len, gfp_mask);
6516 if (!skb)
6517 return NULL;
6518
6519 while (data_len) {
6520 if (nr_frags == MAX_SKB_FRAGS - 1)
6521 goto failure;
6522 while (order && PAGE_ALIGN(data_len) < (PAGE_SIZE << order))
6523 order--;
6524
6525 if (order) {
6526 page = alloc_pages((gfp_mask & ~__GFP_DIRECT_RECLAIM) |
6527 __GFP_COMP |
6528 __GFP_NOWARN,
6529 order);
6530 if (!page) {
6531 order--;
6532 continue;
6533 }
6534 } else {
6535 page = alloc_page(gfp_mask);
6536 if (!page)
6537 goto failure;
6538 }
6539 chunk = min_t(unsigned long, data_len,
6540 PAGE_SIZE << order);
6541 skb_fill_page_desc(skb, nr_frags, page, 0, chunk);
6542 nr_frags++;
6543 skb->truesize += (PAGE_SIZE << order);
6544 data_len -= chunk;
6545 }
6546 return skb;
6547
6548failure:
6549 kfree_skb(skb);
6550 return NULL;
6551}
6552EXPORT_SYMBOL(alloc_skb_with_frags);
6553
6554/* carve out the first off bytes from skb when off < headlen */
6555static int pskb_carve_inside_header(struct sk_buff *skb, const u32 off,
6556 const int headlen, gfp_t gfp_mask)
6557{
6558 int i;
6559 unsigned int size = skb_end_offset(skb);
6560 int new_hlen = headlen - off;
6561 u8 *data;
6562
6563 if (skb_pfmemalloc(skb))
6564 gfp_mask |= __GFP_MEMALLOC;
6565
6566 data = kmalloc_reserve(&size, gfp_mask, NUMA_NO_NODE, NULL);
6567 if (!data)
6568 return -ENOMEM;
6569 size = SKB_WITH_OVERHEAD(size);
6570
6571 /* Copy real data, and all frags */
6572 skb_copy_from_linear_data_offset(skb, off, data, new_hlen);
6573 skb->len -= off;
6574
6575 memcpy((struct skb_shared_info *)(data + size),
6576 skb_shinfo(skb),
6577 offsetof(struct skb_shared_info,
6578 frags[skb_shinfo(skb)->nr_frags]));
6579 if (skb_cloned(skb)) {
6580 /* drop the old head gracefully */
6581 if (skb_orphan_frags(skb, gfp_mask)) {
6582 skb_kfree_head(data, size);
6583 return -ENOMEM;
6584 }
6585 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
6586 skb_frag_ref(skb, i);
6587 if (skb_has_frag_list(skb))
6588 skb_clone_fraglist(skb);
6589 skb_release_data(skb, SKB_CONSUMED, false);
6590 } else {
6591 /* we can reuse existing recount- all we did was
6592 * relocate values
6593 */
6594 skb_free_head(skb, false);
6595 }
6596
6597 skb->head = data;
6598 skb->data = data;
6599 skb->head_frag = 0;
6600 skb_set_end_offset(skb, size);
6601 skb_set_tail_pointer(skb, skb_headlen(skb));
6602 skb_headers_offset_update(skb, 0);
6603 skb->cloned = 0;
6604 skb->hdr_len = 0;
6605 skb->nohdr = 0;
6606 atomic_set(&skb_shinfo(skb)->dataref, 1);
6607
6608 return 0;
6609}
6610
6611static int pskb_carve(struct sk_buff *skb, const u32 off, gfp_t gfp);
6612
6613/* carve out the first eat bytes from skb's frag_list. May recurse into
6614 * pskb_carve()
6615 */
6616static int pskb_carve_frag_list(struct sk_buff *skb,
6617 struct skb_shared_info *shinfo, int eat,
6618 gfp_t gfp_mask)
6619{
6620 struct sk_buff *list = shinfo->frag_list;
6621 struct sk_buff *clone = NULL;
6622 struct sk_buff *insp = NULL;
6623
6624 do {
6625 if (!list) {
6626 pr_err("Not enough bytes to eat. Want %d\n", eat);
6627 return -EFAULT;
6628 }
6629 if (list->len <= eat) {
6630 /* Eaten as whole. */
6631 eat -= list->len;
6632 list = list->next;
6633 insp = list;
6634 } else {
6635 /* Eaten partially. */
6636 if (skb_shared(list)) {
6637 clone = skb_clone(list, gfp_mask);
6638 if (!clone)
6639 return -ENOMEM;
6640 insp = list->next;
6641 list = clone;
6642 } else {
6643 /* This may be pulled without problems. */
6644 insp = list;
6645 }
6646 if (pskb_carve(list, eat, gfp_mask) < 0) {
6647 kfree_skb(clone);
6648 return -ENOMEM;
6649 }
6650 break;
6651 }
6652 } while (eat);
6653
6654 /* Free pulled out fragments. */
6655 while ((list = shinfo->frag_list) != insp) {
6656 shinfo->frag_list = list->next;
6657 consume_skb(list);
6658 }
6659 /* And insert new clone at head. */
6660 if (clone) {
6661 clone->next = list;
6662 shinfo->frag_list = clone;
6663 }
6664 return 0;
6665}
6666
6667/* carve off first len bytes from skb. Split line (off) is in the
6668 * non-linear part of skb
6669 */
6670static int pskb_carve_inside_nonlinear(struct sk_buff *skb, const u32 off,
6671 int pos, gfp_t gfp_mask)
6672{
6673 int i, k = 0;
6674 unsigned int size = skb_end_offset(skb);
6675 u8 *data;
6676 const int nfrags = skb_shinfo(skb)->nr_frags;
6677 struct skb_shared_info *shinfo;
6678
6679 if (skb_pfmemalloc(skb))
6680 gfp_mask |= __GFP_MEMALLOC;
6681
6682 data = kmalloc_reserve(&size, gfp_mask, NUMA_NO_NODE, NULL);
6683 if (!data)
6684 return -ENOMEM;
6685 size = SKB_WITH_OVERHEAD(size);
6686
6687 memcpy((struct skb_shared_info *)(data + size),
6688 skb_shinfo(skb), offsetof(struct skb_shared_info, frags[0]));
6689 if (skb_orphan_frags(skb, gfp_mask)) {
6690 skb_kfree_head(data, size);
6691 return -ENOMEM;
6692 }
6693 shinfo = (struct skb_shared_info *)(data + size);
6694 for (i = 0; i < nfrags; i++) {
6695 int fsize = skb_frag_size(&skb_shinfo(skb)->frags[i]);
6696
6697 if (pos + fsize > off) {
6698 shinfo->frags[k] = skb_shinfo(skb)->frags[i];
6699
6700 if (pos < off) {
6701 /* Split frag.
6702 * We have two variants in this case:
6703 * 1. Move all the frag to the second
6704 * part, if it is possible. F.e.
6705 * this approach is mandatory for TUX,
6706 * where splitting is expensive.
6707 * 2. Split is accurately. We make this.
6708 */
6709 skb_frag_off_add(&shinfo->frags[0], off - pos);
6710 skb_frag_size_sub(&shinfo->frags[0], off - pos);
6711 }
6712 skb_frag_ref(skb, i);
6713 k++;
6714 }
6715 pos += fsize;
6716 }
6717 shinfo->nr_frags = k;
6718 if (skb_has_frag_list(skb))
6719 skb_clone_fraglist(skb);
6720
6721 /* split line is in frag list */
6722 if (k == 0 && pskb_carve_frag_list(skb, shinfo, off - pos, gfp_mask)) {
6723 /* skb_frag_unref() is not needed here as shinfo->nr_frags = 0. */
6724 if (skb_has_frag_list(skb))
6725 kfree_skb_list(skb_shinfo(skb)->frag_list);
6726 skb_kfree_head(data, size);
6727 return -ENOMEM;
6728 }
6729 skb_release_data(skb, SKB_CONSUMED, false);
6730
6731 skb->head = data;
6732 skb->head_frag = 0;
6733 skb->data = data;
6734 skb_set_end_offset(skb, size);
6735 skb_reset_tail_pointer(skb);
6736 skb_headers_offset_update(skb, 0);
6737 skb->cloned = 0;
6738 skb->hdr_len = 0;
6739 skb->nohdr = 0;
6740 skb->len -= off;
6741 skb->data_len = skb->len;
6742 atomic_set(&skb_shinfo(skb)->dataref, 1);
6743 return 0;
6744}
6745
6746/* remove len bytes from the beginning of the skb */
6747static int pskb_carve(struct sk_buff *skb, const u32 len, gfp_t gfp)
6748{
6749 int headlen = skb_headlen(skb);
6750
6751 if (len < headlen)
6752 return pskb_carve_inside_header(skb, len, headlen, gfp);
6753 else
6754 return pskb_carve_inside_nonlinear(skb, len, headlen, gfp);
6755}
6756
6757/* Extract to_copy bytes starting at off from skb, and return this in
6758 * a new skb
6759 */
6760struct sk_buff *pskb_extract(struct sk_buff *skb, int off,
6761 int to_copy, gfp_t gfp)
6762{
6763 struct sk_buff *clone = skb_clone(skb, gfp);
6764
6765 if (!clone)
6766 return NULL;
6767
6768 if (pskb_carve(clone, off, gfp) < 0 ||
6769 pskb_trim(clone, to_copy)) {
6770 kfree_skb(clone);
6771 return NULL;
6772 }
6773 return clone;
6774}
6775EXPORT_SYMBOL(pskb_extract);
6776
6777/**
6778 * skb_condense - try to get rid of fragments/frag_list if possible
6779 * @skb: buffer
6780 *
6781 * Can be used to save memory before skb is added to a busy queue.
6782 * If packet has bytes in frags and enough tail room in skb->head,
6783 * pull all of them, so that we can free the frags right now and adjust
6784 * truesize.
6785 * Notes:
6786 * We do not reallocate skb->head thus can not fail.
6787 * Caller must re-evaluate skb->truesize if needed.
6788 */
6789void skb_condense(struct sk_buff *skb)
6790{
6791 if (skb->data_len) {
6792 if (skb->data_len > skb->end - skb->tail ||
6793 skb_cloned(skb))
6794 return;
6795
6796 /* Nice, we can free page frag(s) right now */
6797 __pskb_pull_tail(skb, skb->data_len);
6798 }
6799 /* At this point, skb->truesize might be over estimated,
6800 * because skb had a fragment, and fragments do not tell
6801 * their truesize.
6802 * When we pulled its content into skb->head, fragment
6803 * was freed, but __pskb_pull_tail() could not possibly
6804 * adjust skb->truesize, not knowing the frag truesize.
6805 */
6806 skb->truesize = SKB_TRUESIZE(skb_end_offset(skb));
6807}
6808EXPORT_SYMBOL(skb_condense);
6809
6810#ifdef CONFIG_SKB_EXTENSIONS
6811static void *skb_ext_get_ptr(struct skb_ext *ext, enum skb_ext_id id)
6812{
6813 return (void *)ext + (ext->offset[id] * SKB_EXT_ALIGN_VALUE);
6814}
6815
6816/**
6817 * __skb_ext_alloc - allocate a new skb extensions storage
6818 *
6819 * @flags: See kmalloc().
6820 *
6821 * Returns the newly allocated pointer. The pointer can later attached to a
6822 * skb via __skb_ext_set().
6823 * Note: caller must handle the skb_ext as an opaque data.
6824 */
6825struct skb_ext *__skb_ext_alloc(gfp_t flags)
6826{
6827 struct skb_ext *new = kmem_cache_alloc(skbuff_ext_cache, flags);
6828
6829 if (new) {
6830 memset(new->offset, 0, sizeof(new->offset));
6831 refcount_set(&new->refcnt, 1);
6832 }
6833
6834 return new;
6835}
6836
6837static struct skb_ext *skb_ext_maybe_cow(struct skb_ext *old,
6838 unsigned int old_active)
6839{
6840 struct skb_ext *new;
6841
6842 if (refcount_read(&old->refcnt) == 1)
6843 return old;
6844
6845 new = kmem_cache_alloc(skbuff_ext_cache, GFP_ATOMIC);
6846 if (!new)
6847 return NULL;
6848
6849 memcpy(new, old, old->chunks * SKB_EXT_ALIGN_VALUE);
6850 refcount_set(&new->refcnt, 1);
6851
6852#ifdef CONFIG_XFRM
6853 if (old_active & (1 << SKB_EXT_SEC_PATH)) {
6854 struct sec_path *sp = skb_ext_get_ptr(old, SKB_EXT_SEC_PATH);
6855 unsigned int i;
6856
6857 for (i = 0; i < sp->len; i++)
6858 xfrm_state_hold(sp->xvec[i]);
6859 }
6860#endif
6861#ifdef CONFIG_MCTP_FLOWS
6862 if (old_active & (1 << SKB_EXT_MCTP)) {
6863 struct mctp_flow *flow = skb_ext_get_ptr(old, SKB_EXT_MCTP);
6864
6865 if (flow->key)
6866 refcount_inc(&flow->key->refs);
6867 }
6868#endif
6869 __skb_ext_put(old);
6870 return new;
6871}
6872
6873/**
6874 * __skb_ext_set - attach the specified extension storage to this skb
6875 * @skb: buffer
6876 * @id: extension id
6877 * @ext: extension storage previously allocated via __skb_ext_alloc()
6878 *
6879 * Existing extensions, if any, are cleared.
6880 *
6881 * Returns the pointer to the extension.
6882 */
6883void *__skb_ext_set(struct sk_buff *skb, enum skb_ext_id id,
6884 struct skb_ext *ext)
6885{
6886 unsigned int newlen, newoff = SKB_EXT_CHUNKSIZEOF(*ext);
6887
6888 skb_ext_put(skb);
6889 newlen = newoff + skb_ext_type_len[id];
6890 ext->chunks = newlen;
6891 ext->offset[id] = newoff;
6892 skb->extensions = ext;
6893 skb->active_extensions = 1 << id;
6894 return skb_ext_get_ptr(ext, id);
6895}
6896
6897/**
6898 * skb_ext_add - allocate space for given extension, COW if needed
6899 * @skb: buffer
6900 * @id: extension to allocate space for
6901 *
6902 * Allocates enough space for the given extension.
6903 * If the extension is already present, a pointer to that extension
6904 * is returned.
6905 *
6906 * If the skb was cloned, COW applies and the returned memory can be
6907 * modified without changing the extension space of clones buffers.
6908 *
6909 * Returns pointer to the extension or NULL on allocation failure.
6910 */
6911void *skb_ext_add(struct sk_buff *skb, enum skb_ext_id id)
6912{
6913 struct skb_ext *new, *old = NULL;
6914 unsigned int newlen, newoff;
6915
6916 if (skb->active_extensions) {
6917 old = skb->extensions;
6918
6919 new = skb_ext_maybe_cow(old, skb->active_extensions);
6920 if (!new)
6921 return NULL;
6922
6923 if (__skb_ext_exist(new, id))
6924 goto set_active;
6925
6926 newoff = new->chunks;
6927 } else {
6928 newoff = SKB_EXT_CHUNKSIZEOF(*new);
6929
6930 new = __skb_ext_alloc(GFP_ATOMIC);
6931 if (!new)
6932 return NULL;
6933 }
6934
6935 newlen = newoff + skb_ext_type_len[id];
6936 new->chunks = newlen;
6937 new->offset[id] = newoff;
6938set_active:
6939 skb->slow_gro = 1;
6940 skb->extensions = new;
6941 skb->active_extensions |= 1 << id;
6942 return skb_ext_get_ptr(new, id);
6943}
6944EXPORT_SYMBOL(skb_ext_add);
6945
6946#ifdef CONFIG_XFRM
6947static void skb_ext_put_sp(struct sec_path *sp)
6948{
6949 unsigned int i;
6950
6951 for (i = 0; i < sp->len; i++)
6952 xfrm_state_put(sp->xvec[i]);
6953}
6954#endif
6955
6956#ifdef CONFIG_MCTP_FLOWS
6957static void skb_ext_put_mctp(struct mctp_flow *flow)
6958{
6959 if (flow->key)
6960 mctp_key_unref(flow->key);
6961}
6962#endif
6963
6964void __skb_ext_del(struct sk_buff *skb, enum skb_ext_id id)
6965{
6966 struct skb_ext *ext = skb->extensions;
6967
6968 skb->active_extensions &= ~(1 << id);
6969 if (skb->active_extensions == 0) {
6970 skb->extensions = NULL;
6971 __skb_ext_put(ext);
6972#ifdef CONFIG_XFRM
6973 } else if (id == SKB_EXT_SEC_PATH &&
6974 refcount_read(&ext->refcnt) == 1) {
6975 struct sec_path *sp = skb_ext_get_ptr(ext, SKB_EXT_SEC_PATH);
6976
6977 skb_ext_put_sp(sp);
6978 sp->len = 0;
6979#endif
6980 }
6981}
6982EXPORT_SYMBOL(__skb_ext_del);
6983
6984void __skb_ext_put(struct skb_ext *ext)
6985{
6986 /* If this is last clone, nothing can increment
6987 * it after check passes. Avoids one atomic op.
6988 */
6989 if (refcount_read(&ext->refcnt) == 1)
6990 goto free_now;
6991
6992 if (!refcount_dec_and_test(&ext->refcnt))
6993 return;
6994free_now:
6995#ifdef CONFIG_XFRM
6996 if (__skb_ext_exist(ext, SKB_EXT_SEC_PATH))
6997 skb_ext_put_sp(skb_ext_get_ptr(ext, SKB_EXT_SEC_PATH));
6998#endif
6999#ifdef CONFIG_MCTP_FLOWS
7000 if (__skb_ext_exist(ext, SKB_EXT_MCTP))
7001 skb_ext_put_mctp(skb_ext_get_ptr(ext, SKB_EXT_MCTP));
7002#endif
7003
7004 kmem_cache_free(skbuff_ext_cache, ext);
7005}
7006EXPORT_SYMBOL(__skb_ext_put);
7007#endif /* CONFIG_SKB_EXTENSIONS */
7008
7009/**
7010 * skb_attempt_defer_free - queue skb for remote freeing
7011 * @skb: buffer
7012 *
7013 * Put @skb in a per-cpu list, using the cpu which
7014 * allocated the skb/pages to reduce false sharing
7015 * and memory zone spinlock contention.
7016 */
7017void skb_attempt_defer_free(struct sk_buff *skb)
7018{
7019 int cpu = skb->alloc_cpu;
7020 struct softnet_data *sd;
7021 unsigned int defer_max;
7022 bool kick;
7023
7024 if (WARN_ON_ONCE(cpu >= nr_cpu_ids) ||
7025 !cpu_online(cpu) ||
7026 cpu == raw_smp_processor_id()) {
7027nodefer: __kfree_skb(skb);
7028 return;
7029 }
7030
7031 DEBUG_NET_WARN_ON_ONCE(skb_dst(skb));
7032 DEBUG_NET_WARN_ON_ONCE(skb->destructor);
7033
7034 sd = &per_cpu(softnet_data, cpu);
7035 defer_max = READ_ONCE(sysctl_skb_defer_max);
7036 if (READ_ONCE(sd->defer_count) >= defer_max)
7037 goto nodefer;
7038
7039 spin_lock_bh(&sd->defer_lock);
7040 /* Send an IPI every time queue reaches half capacity. */
7041 kick = sd->defer_count == (defer_max >> 1);
7042 /* Paired with the READ_ONCE() few lines above */
7043 WRITE_ONCE(sd->defer_count, sd->defer_count + 1);
7044
7045 skb->next = sd->defer_list;
7046 /* Paired with READ_ONCE() in skb_defer_free_flush() */
7047 WRITE_ONCE(sd->defer_list, skb);
7048 spin_unlock_bh(&sd->defer_lock);
7049
7050 /* Make sure to trigger NET_RX_SOFTIRQ on the remote CPU
7051 * if we are unlucky enough (this seems very unlikely).
7052 */
7053 if (unlikely(kick) && !cmpxchg(&sd->defer_ipi_scheduled, 0, 1))
7054 smp_call_function_single_async(cpu, &sd->defer_csd);
7055}
7056
7057static void skb_splice_csum_page(struct sk_buff *skb, struct page *page,
7058 size_t offset, size_t len)
7059{
7060 const char *kaddr;
7061 __wsum csum;
7062
7063 kaddr = kmap_local_page(page);
7064 csum = csum_partial(kaddr + offset, len, 0);
7065 kunmap_local(kaddr);
7066 skb->csum = csum_block_add(skb->csum, csum, skb->len);
7067}
7068
7069/**
7070 * skb_splice_from_iter - Splice (or copy) pages to skbuff
7071 * @skb: The buffer to add pages to
7072 * @iter: Iterator representing the pages to be added
7073 * @maxsize: Maximum amount of pages to be added
7074 * @gfp: Allocation flags
7075 *
7076 * This is a common helper function for supporting MSG_SPLICE_PAGES. It
7077 * extracts pages from an iterator and adds them to the socket buffer if
7078 * possible, copying them to fragments if not possible (such as if they're slab
7079 * pages).
7080 *
7081 * Returns the amount of data spliced/copied or -EMSGSIZE if there's
7082 * insufficient space in the buffer to transfer anything.
7083 */
7084ssize_t skb_splice_from_iter(struct sk_buff *skb, struct iov_iter *iter,
7085 ssize_t maxsize, gfp_t gfp)
7086{
7087 size_t frag_limit = READ_ONCE(sysctl_max_skb_frags);
7088 struct page *pages[8], **ppages = pages;
7089 ssize_t spliced = 0, ret = 0;
7090 unsigned int i;
7091
7092 while (iter->count > 0) {
7093 ssize_t space, nr, len;
7094 size_t off;
7095
7096 ret = -EMSGSIZE;
7097 space = frag_limit - skb_shinfo(skb)->nr_frags;
7098 if (space < 0)
7099 break;
7100
7101 /* We might be able to coalesce without increasing nr_frags */
7102 nr = clamp_t(size_t, space, 1, ARRAY_SIZE(pages));
7103
7104 len = iov_iter_extract_pages(iter, &ppages, maxsize, nr, 0, &off);
7105 if (len <= 0) {
7106 ret = len ?: -EIO;
7107 break;
7108 }
7109
7110 i = 0;
7111 do {
7112 struct page *page = pages[i++];
7113 size_t part = min_t(size_t, PAGE_SIZE - off, len);
7114
7115 ret = -EIO;
7116 if (WARN_ON_ONCE(!sendpage_ok(page)))
7117 goto out;
7118
7119 ret = skb_append_pagefrags(skb, page, off, part,
7120 frag_limit);
7121 if (ret < 0) {
7122 iov_iter_revert(iter, len);
7123 goto out;
7124 }
7125
7126 if (skb->ip_summed == CHECKSUM_NONE)
7127 skb_splice_csum_page(skb, page, off, part);
7128
7129 off = 0;
7130 spliced += part;
7131 maxsize -= part;
7132 len -= part;
7133 } while (len > 0);
7134
7135 if (maxsize <= 0)
7136 break;
7137 }
7138
7139out:
7140 skb_len_add(skb, spliced);
7141 return spliced ?: ret;
7142}
7143EXPORT_SYMBOL(skb_splice_from_iter);
7144
7145static __always_inline
7146size_t memcpy_from_iter_csum(void *iter_from, size_t progress,
7147 size_t len, void *to, void *priv2)
7148{
7149 __wsum *csum = priv2;
7150 __wsum next = csum_partial_copy_nocheck(iter_from, to + progress, len);
7151
7152 *csum = csum_block_add(*csum, next, progress);
7153 return 0;
7154}
7155
7156static __always_inline
7157size_t copy_from_user_iter_csum(void __user *iter_from, size_t progress,
7158 size_t len, void *to, void *priv2)
7159{
7160 __wsum next, *csum = priv2;
7161
7162 next = csum_and_copy_from_user(iter_from, to + progress, len);
7163 *csum = csum_block_add(*csum, next, progress);
7164 return next ? 0 : len;
7165}
7166
7167bool csum_and_copy_from_iter_full(void *addr, size_t bytes,
7168 __wsum *csum, struct iov_iter *i)
7169{
7170 size_t copied;
7171
7172 if (WARN_ON_ONCE(!i->data_source))
7173 return false;
7174 copied = iterate_and_advance2(i, bytes, addr, csum,
7175 copy_from_user_iter_csum,
7176 memcpy_from_iter_csum);
7177 if (likely(copied == bytes))
7178 return true;
7179 iov_iter_revert(i, copied);
7180 return false;
7181}
7182EXPORT_SYMBOL(csum_and_copy_from_iter_full);