2 * Routines having to do with the 'struct sk_buff' memory handlers.
4 * Authors: Alan Cox <iiitac@pyr.swan.ac.uk>
5 * Florian La Roche <rzsfl@rz.uni-sb.de>
7 * Version: $Id: skbuff.c,v 1.90 2001/11/07 05:56:19 davem Exp $
10 * Alan Cox : Fixed the worst of the load
12 * Dave Platt : Interrupt stacking fix.
13 * Richard Kooijman : Timestamp fixes.
14 * Alan Cox : Changed buffer format.
15 * Alan Cox : destructor hook for AF_UNIX etc.
16 * Linus Torvalds : Better skb_clone.
17 * Alan Cox : Added skb_copy.
18 * Alan Cox : Added all the changed routines Linus
19 * only put in the headers
20 * Ray VanTassle : Fixed --skb->lock in free
21 * Alan Cox : skb_copy copy arp field
22 * Andi Kleen : slabified it.
23 * Robert Olsson : Removed skb_head_pool
26 * The __skb_ routines should be called with interrupts
27 * disabled, or you better be *real* sure that the operation is atomic
28 * with respect to whatever list is being frobbed (e.g. via lock_sock()
29 * or via disabling bottom half handlers, etc).
31 * This program is free software; you can redistribute it and/or
32 * modify it under the terms of the GNU General Public License
33 * as published by the Free Software Foundation; either version
34 * 2 of the License, or (at your option) any later version.
38 * The functions in this file will not compile correctly with gcc 2.4.x
41 #include <linux/module.h>
42 #include <linux/types.h>
43 #include <linux/kernel.h>
45 #include <linux/interrupt.h>
47 #include <linux/inet.h>
48 #include <linux/slab.h>
49 #include <linux/netdevice.h>
50 #ifdef CONFIG_NET_CLS_ACT
51 #include <net/pkt_sched.h>
53 #include <linux/string.h>
54 #include <linux/skbuff.h>
55 #include <linux/cache.h>
56 #include <linux/rtnetlink.h>
57 #include <linux/init.h>
59 #include <net/protocol.h>
62 #include <net/checksum.h>
65 #include <asm/uaccess.h>
66 #include <asm/system.h>
70 static struct kmem_cache *skbuff_head_cache __read_mostly;
71 static struct kmem_cache *skbuff_fclone_cache __read_mostly;
74 * Keep out-of-line to prevent kernel bloat.
75 * __builtin_return_address is not used because it is not always
80 * skb_over_panic - private function
85 * Out of line support code for skb_put(). Not user callable.
87 void skb_over_panic(struct sk_buff *skb, int sz, void *here)
89 printk(KERN_EMERG "skb_over_panic: text:%p len:%d put:%d head:%p "
90 "data:%p tail:%p end:%p dev:%s\n",
91 here, skb->len, sz, skb->head, skb->data, skb->tail, skb->end,
92 skb->dev ? skb->dev->name : "<NULL>");
97 * skb_under_panic - private function
102 * Out of line support code for skb_push(). Not user callable.
105 void skb_under_panic(struct sk_buff *skb, int sz, void *here)
107 printk(KERN_EMERG "skb_under_panic: text:%p len:%d put:%d head:%p "
108 "data:%p tail:%p end:%p dev:%s\n",
109 here, skb->len, sz, skb->head, skb->data, skb->tail, skb->end,
110 skb->dev ? skb->dev->name : "<NULL>");
114 void skb_truesize_bug(struct sk_buff *skb)
116 printk(KERN_ERR "SKB BUG: Invalid truesize (%u) "
117 "len=%u, sizeof(sk_buff)=%Zd\n",
118 skb->truesize, skb->len, sizeof(struct sk_buff));
120 EXPORT_SYMBOL(skb_truesize_bug);
122 /* Allocate a new skbuff. We do this ourselves so we can fill in a few
123 * 'private' fields and also do memory statistics to find all the
129 * __alloc_skb - allocate a network buffer
130 * @size: size to allocate
131 * @gfp_mask: allocation mask
132 * @fclone: allocate from fclone cache instead of head cache
133 * and allocate a cloned (child) skb
134 * @node: numa node to allocate memory on
136 * Allocate a new &sk_buff. The returned buffer has no headroom and a
137 * tail room of size bytes. The object has a reference count of one.
138 * The return is the buffer. On a failure the return is %NULL.
140 * Buffers may only be allocated from interrupts using a @gfp_mask of
143 struct sk_buff *__alloc_skb(unsigned int size, gfp_t gfp_mask,
144 int fclone, int node)
146 struct kmem_cache *cache;
147 struct skb_shared_info *shinfo;
151 cache = fclone ? skbuff_fclone_cache : skbuff_head_cache;
154 skb = kmem_cache_alloc_node(cache, gfp_mask & ~__GFP_DMA, node);
158 /* Get the DATA. Size must match skb_add_mtu(). */
159 size = SKB_DATA_ALIGN(size);
160 data = kmalloc_node_track_caller(size + sizeof(struct skb_shared_info),
165 memset(skb, 0, offsetof(struct sk_buff, truesize));
166 skb->truesize = size + sizeof(struct sk_buff);
167 atomic_set(&skb->users, 1);
171 skb->end = data + size;
172 /* make sure we initialize shinfo sequentially */
173 shinfo = skb_shinfo(skb);
174 atomic_set(&shinfo->dataref, 1);
175 shinfo->nr_frags = 0;
176 shinfo->gso_size = 0;
177 shinfo->gso_segs = 0;
178 shinfo->gso_type = 0;
179 shinfo->ip6_frag_id = 0;
180 shinfo->frag_list = NULL;
183 struct sk_buff *child = skb + 1;
184 atomic_t *fclone_ref = (atomic_t *) (child + 1);
186 skb->fclone = SKB_FCLONE_ORIG;
187 atomic_set(fclone_ref, 1);
189 child->fclone = SKB_FCLONE_UNAVAILABLE;
194 kmem_cache_free(cache, skb);
200 * __netdev_alloc_skb - allocate an skbuff for rx on a specific device
201 * @dev: network device to receive on
202 * @length: length to allocate
203 * @gfp_mask: get_free_pages mask, passed to alloc_skb
205 * Allocate a new &sk_buff and assign it a usage count of one. The
206 * buffer has unspecified headroom built in. Users should allocate
207 * the headroom they think they need without accounting for the
208 * built in space. The built in space is used for optimisations.
210 * %NULL is returned if there is no free memory.
212 struct sk_buff *__netdev_alloc_skb(struct net_device *dev,
213 unsigned int length, gfp_t gfp_mask)
215 int node = dev->dev.parent ? dev_to_node(dev->dev.parent) : -1;
218 skb = __alloc_skb(length + NET_SKB_PAD, gfp_mask, 0, node);
220 skb_reserve(skb, NET_SKB_PAD);
226 static void skb_drop_list(struct sk_buff **listp)
228 struct sk_buff *list = *listp;
233 struct sk_buff *this = list;
239 static inline void skb_drop_fraglist(struct sk_buff *skb)
241 skb_drop_list(&skb_shinfo(skb)->frag_list);
244 static void skb_clone_fraglist(struct sk_buff *skb)
246 struct sk_buff *list;
248 for (list = skb_shinfo(skb)->frag_list; list; list = list->next)
252 static void skb_release_data(struct sk_buff *skb)
255 !atomic_sub_return(skb->nohdr ? (1 << SKB_DATAREF_SHIFT) + 1 : 1,
256 &skb_shinfo(skb)->dataref)) {
257 if (skb_shinfo(skb)->nr_frags) {
259 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
260 put_page(skb_shinfo(skb)->frags[i].page);
263 if (skb_shinfo(skb)->frag_list)
264 skb_drop_fraglist(skb);
271 * Free an skbuff by memory without cleaning the state.
273 void kfree_skbmem(struct sk_buff *skb)
275 struct sk_buff *other;
276 atomic_t *fclone_ref;
278 skb_release_data(skb);
279 switch (skb->fclone) {
280 case SKB_FCLONE_UNAVAILABLE:
281 kmem_cache_free(skbuff_head_cache, skb);
284 case SKB_FCLONE_ORIG:
285 fclone_ref = (atomic_t *) (skb + 2);
286 if (atomic_dec_and_test(fclone_ref))
287 kmem_cache_free(skbuff_fclone_cache, skb);
290 case SKB_FCLONE_CLONE:
291 fclone_ref = (atomic_t *) (skb + 1);
294 /* The clone portion is available for
295 * fast-cloning again.
297 skb->fclone = SKB_FCLONE_UNAVAILABLE;
299 if (atomic_dec_and_test(fclone_ref))
300 kmem_cache_free(skbuff_fclone_cache, other);
306 * __kfree_skb - private function
309 * Free an sk_buff. Release anything attached to the buffer.
310 * Clean the state. This is an internal helper function. Users should
311 * always call kfree_skb
314 void __kfree_skb(struct sk_buff *skb)
316 dst_release(skb->dst);
318 secpath_put(skb->sp);
320 if (skb->destructor) {
322 skb->destructor(skb);
324 #ifdef CONFIG_NETFILTER
325 nf_conntrack_put(skb->nfct);
326 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
327 nf_conntrack_put_reasm(skb->nfct_reasm);
329 #ifdef CONFIG_BRIDGE_NETFILTER
330 nf_bridge_put(skb->nf_bridge);
333 /* XXX: IS this still necessary? - JHS */
334 #ifdef CONFIG_NET_SCHED
336 #ifdef CONFIG_NET_CLS_ACT
345 * kfree_skb - free an sk_buff
346 * @skb: buffer to free
348 * Drop a reference to the buffer and free it if the usage count has
351 void kfree_skb(struct sk_buff *skb)
355 if (likely(atomic_read(&skb->users) == 1))
357 else if (likely(!atomic_dec_and_test(&skb->users)))
363 * skb_clone - duplicate an sk_buff
364 * @skb: buffer to clone
365 * @gfp_mask: allocation priority
367 * Duplicate an &sk_buff. The new one is not owned by a socket. Both
368 * copies share the same packet data but not structure. The new
369 * buffer has a reference count of 1. If the allocation fails the
370 * function returns %NULL otherwise the new buffer is returned.
372 * If this function is called from an interrupt gfp_mask() must be
376 struct sk_buff *skb_clone(struct sk_buff *skb, gfp_t gfp_mask)
381 if (skb->fclone == SKB_FCLONE_ORIG &&
382 n->fclone == SKB_FCLONE_UNAVAILABLE) {
383 atomic_t *fclone_ref = (atomic_t *) (n + 1);
384 n->fclone = SKB_FCLONE_CLONE;
385 atomic_inc(fclone_ref);
387 n = kmem_cache_alloc(skbuff_head_cache, gfp_mask);
390 n->fclone = SKB_FCLONE_UNAVAILABLE;
393 #define C(x) n->x = skb->x
395 n->next = n->prev = NULL;
406 secpath_get(skb->sp);
408 memcpy(n->cb, skb->cb, sizeof(skb->cb));
419 #if defined(CONFIG_IP_VS) || defined(CONFIG_IP_VS_MODULE)
423 n->destructor = NULL;
426 #ifdef CONFIG_NET_SCHED
428 #ifdef CONFIG_NET_CLS_ACT
429 n->tc_verd = SET_TC_VERD(skb->tc_verd,0);
430 n->tc_verd = CLR_TC_OK2MUNGE(n->tc_verd);
431 n->tc_verd = CLR_TC_MUNGED(n->tc_verd);
434 skb_copy_secmark(n, skb);
437 atomic_set(&n->users, 1);
443 atomic_inc(&(skb_shinfo(skb)->dataref));
449 static void copy_skb_header(struct sk_buff *new, const struct sk_buff *old)
452 * Shift between the two data areas in bytes
454 unsigned long offset = new->data - old->data;
458 new->priority = old->priority;
459 new->protocol = old->protocol;
460 new->dst = dst_clone(old->dst);
462 new->sp = secpath_get(old->sp);
464 new->h.raw = old->h.raw + offset;
465 new->nh.raw = old->nh.raw + offset;
466 new->mac.raw = old->mac.raw + offset;
467 memcpy(new->cb, old->cb, sizeof(old->cb));
468 new->local_df = old->local_df;
469 new->fclone = SKB_FCLONE_UNAVAILABLE;
470 new->pkt_type = old->pkt_type;
471 new->tstamp = old->tstamp;
472 new->destructor = NULL;
473 new->mark = old->mark;
475 #if defined(CONFIG_IP_VS) || defined(CONFIG_IP_VS_MODULE)
476 new->ipvs_property = old->ipvs_property;
478 #ifdef CONFIG_NET_SCHED
479 #ifdef CONFIG_NET_CLS_ACT
480 new->tc_verd = old->tc_verd;
482 new->tc_index = old->tc_index;
484 skb_copy_secmark(new, old);
485 atomic_set(&new->users, 1);
486 skb_shinfo(new)->gso_size = skb_shinfo(old)->gso_size;
487 skb_shinfo(new)->gso_segs = skb_shinfo(old)->gso_segs;
488 skb_shinfo(new)->gso_type = skb_shinfo(old)->gso_type;
492 * skb_copy - create private copy of an sk_buff
493 * @skb: buffer to copy
494 * @gfp_mask: allocation priority
496 * Make a copy of both an &sk_buff and its data. This is used when the
497 * caller wishes to modify the data and needs a private copy of the
498 * data to alter. Returns %NULL on failure or the pointer to the buffer
499 * on success. The returned buffer has a reference count of 1.
501 * As by-product this function converts non-linear &sk_buff to linear
502 * one, so that &sk_buff becomes completely private and caller is allowed
503 * to modify all the data of returned buffer. This means that this
504 * function is not recommended for use in circumstances when only
505 * header is going to be modified. Use pskb_copy() instead.
508 struct sk_buff *skb_copy(const struct sk_buff *skb, gfp_t gfp_mask)
510 int headerlen = skb->data - skb->head;
512 * Allocate the copy buffer
514 struct sk_buff *n = alloc_skb(skb->end - skb->head + skb->data_len,
519 /* Set the data pointer */
520 skb_reserve(n, headerlen);
521 /* Set the tail pointer and length */
522 skb_put(n, skb->len);
524 n->ip_summed = skb->ip_summed;
526 if (skb_copy_bits(skb, -headerlen, n->head, headerlen + skb->len))
529 copy_skb_header(n, skb);
535 * pskb_copy - create copy of an sk_buff with private head.
536 * @skb: buffer to copy
537 * @gfp_mask: allocation priority
539 * Make a copy of both an &sk_buff and part of its data, located
540 * in header. Fragmented data remain shared. This is used when
541 * the caller wishes to modify only header of &sk_buff and needs
542 * private copy of the header to alter. Returns %NULL on failure
543 * or the pointer to the buffer on success.
544 * The returned buffer has a reference count of 1.
547 struct sk_buff *pskb_copy(struct sk_buff *skb, gfp_t gfp_mask)
550 * Allocate the copy buffer
552 struct sk_buff *n = alloc_skb(skb->end - skb->head, gfp_mask);
557 /* Set the data pointer */
558 skb_reserve(n, skb->data - skb->head);
559 /* Set the tail pointer and length */
560 skb_put(n, skb_headlen(skb));
562 memcpy(n->data, skb->data, n->len);
564 n->ip_summed = skb->ip_summed;
566 n->truesize += skb->data_len;
567 n->data_len = skb->data_len;
570 if (skb_shinfo(skb)->nr_frags) {
573 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
574 skb_shinfo(n)->frags[i] = skb_shinfo(skb)->frags[i];
575 get_page(skb_shinfo(n)->frags[i].page);
577 skb_shinfo(n)->nr_frags = i;
580 if (skb_shinfo(skb)->frag_list) {
581 skb_shinfo(n)->frag_list = skb_shinfo(skb)->frag_list;
582 skb_clone_fraglist(n);
585 copy_skb_header(n, skb);
591 * pskb_expand_head - reallocate header of &sk_buff
592 * @skb: buffer to reallocate
593 * @nhead: room to add at head
594 * @ntail: room to add at tail
595 * @gfp_mask: allocation priority
597 * Expands (or creates identical copy, if &nhead and &ntail are zero)
598 * header of skb. &sk_buff itself is not changed. &sk_buff MUST have
599 * reference count of 1. Returns zero in the case of success or error,
600 * if expansion failed. In the last case, &sk_buff is not changed.
602 * All the pointers pointing into skb header may change and must be
603 * reloaded after call to this function.
606 int pskb_expand_head(struct sk_buff *skb, int nhead, int ntail,
611 int size = nhead + (skb->end - skb->head) + ntail;
617 size = SKB_DATA_ALIGN(size);
619 data = kmalloc(size + sizeof(struct skb_shared_info), gfp_mask);
623 /* Copy only real data... and, alas, header. This should be
624 * optimized for the cases when header is void. */
625 memcpy(data + nhead, skb->head, skb->tail - skb->head);
626 memcpy(data + size, skb->end, sizeof(struct skb_shared_info));
628 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
629 get_page(skb_shinfo(skb)->frags[i].page);
631 if (skb_shinfo(skb)->frag_list)
632 skb_clone_fraglist(skb);
634 skb_release_data(skb);
636 off = (data + nhead) - skb->head;
639 skb->end = data + size;
647 atomic_set(&skb_shinfo(skb)->dataref, 1);
654 /* Make private copy of skb with writable head and some headroom */
656 struct sk_buff *skb_realloc_headroom(struct sk_buff *skb, unsigned int headroom)
658 struct sk_buff *skb2;
659 int delta = headroom - skb_headroom(skb);
662 skb2 = pskb_copy(skb, GFP_ATOMIC);
664 skb2 = skb_clone(skb, GFP_ATOMIC);
665 if (skb2 && pskb_expand_head(skb2, SKB_DATA_ALIGN(delta), 0,
676 * skb_copy_expand - copy and expand sk_buff
677 * @skb: buffer to copy
678 * @newheadroom: new free bytes at head
679 * @newtailroom: new free bytes at tail
680 * @gfp_mask: allocation priority
682 * Make a copy of both an &sk_buff and its data and while doing so
683 * allocate additional space.
685 * This is used when the caller wishes to modify the data and needs a
686 * private copy of the data to alter as well as more space for new fields.
687 * Returns %NULL on failure or the pointer to the buffer
688 * on success. The returned buffer has a reference count of 1.
690 * You must pass %GFP_ATOMIC as the allocation priority if this function
691 * is called from an interrupt.
693 * BUG ALERT: ip_summed is not copied. Why does this work? Is it used
694 * only by netfilter in the cases when checksum is recalculated? --ANK
696 struct sk_buff *skb_copy_expand(const struct sk_buff *skb,
697 int newheadroom, int newtailroom,
701 * Allocate the copy buffer
703 struct sk_buff *n = alloc_skb(newheadroom + skb->len + newtailroom,
705 int head_copy_len, head_copy_off;
710 skb_reserve(n, newheadroom);
712 /* Set the tail pointer and length */
713 skb_put(n, skb->len);
715 head_copy_len = skb_headroom(skb);
717 if (newheadroom <= head_copy_len)
718 head_copy_len = newheadroom;
720 head_copy_off = newheadroom - head_copy_len;
722 /* Copy the linear header and data. */
723 if (skb_copy_bits(skb, -head_copy_len, n->head + head_copy_off,
724 skb->len + head_copy_len))
727 copy_skb_header(n, skb);
733 * skb_pad - zero pad the tail of an skb
734 * @skb: buffer to pad
737 * Ensure that a buffer is followed by a padding area that is zero
738 * filled. Used by network drivers which may DMA or transfer data
739 * beyond the buffer end onto the wire.
741 * May return error in out of memory cases. The skb is freed on error.
744 int skb_pad(struct sk_buff *skb, int pad)
749 /* If the skbuff is non linear tailroom is always zero.. */
750 if (!skb_cloned(skb) && skb_tailroom(skb) >= pad) {
751 memset(skb->data+skb->len, 0, pad);
755 ntail = skb->data_len + pad - (skb->end - skb->tail);
756 if (likely(skb_cloned(skb) || ntail > 0)) {
757 err = pskb_expand_head(skb, 0, ntail, GFP_ATOMIC);
762 /* FIXME: The use of this function with non-linear skb's really needs
765 err = skb_linearize(skb);
769 memset(skb->data + skb->len, 0, pad);
777 /* Trims skb to length len. It can change skb pointers.
780 int ___pskb_trim(struct sk_buff *skb, unsigned int len)
782 struct sk_buff **fragp;
783 struct sk_buff *frag;
784 int offset = skb_headlen(skb);
785 int nfrags = skb_shinfo(skb)->nr_frags;
789 if (skb_cloned(skb) &&
790 unlikely((err = pskb_expand_head(skb, 0, 0, GFP_ATOMIC))))
797 for (; i < nfrags; i++) {
798 int end = offset + skb_shinfo(skb)->frags[i].size;
805 skb_shinfo(skb)->frags[i++].size = len - offset;
808 skb_shinfo(skb)->nr_frags = i;
810 for (; i < nfrags; i++)
811 put_page(skb_shinfo(skb)->frags[i].page);
813 if (skb_shinfo(skb)->frag_list)
814 skb_drop_fraglist(skb);
818 for (fragp = &skb_shinfo(skb)->frag_list; (frag = *fragp);
819 fragp = &frag->next) {
820 int end = offset + frag->len;
822 if (skb_shared(frag)) {
823 struct sk_buff *nfrag;
825 nfrag = skb_clone(frag, GFP_ATOMIC);
826 if (unlikely(!nfrag))
829 nfrag->next = frag->next;
841 unlikely((err = pskb_trim(frag, len - offset))))
845 skb_drop_list(&frag->next);
850 if (len > skb_headlen(skb)) {
851 skb->data_len -= skb->len - len;
856 skb->tail = skb->data + len;
863 * __pskb_pull_tail - advance tail of skb header
864 * @skb: buffer to reallocate
865 * @delta: number of bytes to advance tail
867 * The function makes a sense only on a fragmented &sk_buff,
868 * it expands header moving its tail forward and copying necessary
869 * data from fragmented part.
871 * &sk_buff MUST have reference count of 1.
873 * Returns %NULL (and &sk_buff does not change) if pull failed
874 * or value of new tail of skb in the case of success.
876 * All the pointers pointing into skb header may change and must be
877 * reloaded after call to this function.
880 /* Moves tail of skb head forward, copying data from fragmented part,
881 * when it is necessary.
882 * 1. It may fail due to malloc failure.
883 * 2. It may change skb pointers.
885 * It is pretty complicated. Luckily, it is called only in exceptional cases.
887 unsigned char *__pskb_pull_tail(struct sk_buff *skb, int delta)
889 /* If skb has not enough free space at tail, get new one
890 * plus 128 bytes for future expansions. If we have enough
891 * room at tail, reallocate without expansion only if skb is cloned.
893 int i, k, eat = (skb->tail + delta) - skb->end;
895 if (eat > 0 || skb_cloned(skb)) {
896 if (pskb_expand_head(skb, 0, eat > 0 ? eat + 128 : 0,
901 if (skb_copy_bits(skb, skb_headlen(skb), skb->tail, delta))
904 /* Optimization: no fragments, no reasons to preestimate
905 * size of pulled pages. Superb.
907 if (!skb_shinfo(skb)->frag_list)
910 /* Estimate size of pulled pages. */
912 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
913 if (skb_shinfo(skb)->frags[i].size >= eat)
915 eat -= skb_shinfo(skb)->frags[i].size;
918 /* If we need update frag list, we are in troubles.
919 * Certainly, it possible to add an offset to skb data,
920 * but taking into account that pulling is expected to
921 * be very rare operation, it is worth to fight against
922 * further bloating skb head and crucify ourselves here instead.
923 * Pure masohism, indeed. 8)8)
926 struct sk_buff *list = skb_shinfo(skb)->frag_list;
927 struct sk_buff *clone = NULL;
928 struct sk_buff *insp = NULL;
933 if (list->len <= eat) {
934 /* Eaten as whole. */
939 /* Eaten partially. */
941 if (skb_shared(list)) {
942 /* Sucks! We need to fork list. :-( */
943 clone = skb_clone(list, GFP_ATOMIC);
949 /* This may be pulled without
953 if (!pskb_pull(list, eat)) {
962 /* Free pulled out fragments. */
963 while ((list = skb_shinfo(skb)->frag_list) != insp) {
964 skb_shinfo(skb)->frag_list = list->next;
967 /* And insert new clone at head. */
970 skb_shinfo(skb)->frag_list = clone;
973 /* Success! Now we may commit changes to skb data. */
978 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
979 if (skb_shinfo(skb)->frags[i].size <= eat) {
980 put_page(skb_shinfo(skb)->frags[i].page);
981 eat -= skb_shinfo(skb)->frags[i].size;
983 skb_shinfo(skb)->frags[k] = skb_shinfo(skb)->frags[i];
985 skb_shinfo(skb)->frags[k].page_offset += eat;
986 skb_shinfo(skb)->frags[k].size -= eat;
992 skb_shinfo(skb)->nr_frags = k;
995 skb->data_len -= delta;
1000 /* Copy some data bits from skb to kernel buffer. */
1002 int skb_copy_bits(const struct sk_buff *skb, int offset, void *to, int len)
1005 int start = skb_headlen(skb);
1007 if (offset > (int)skb->len - len)
1011 if ((copy = start - offset) > 0) {
1014 memcpy(to, skb->data + offset, copy);
1015 if ((len -= copy) == 0)
1021 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
1024 BUG_TRAP(start <= offset + len);
1026 end = start + skb_shinfo(skb)->frags[i].size;
1027 if ((copy = end - offset) > 0) {
1033 vaddr = kmap_skb_frag(&skb_shinfo(skb)->frags[i]);
1035 vaddr + skb_shinfo(skb)->frags[i].page_offset+
1036 offset - start, copy);
1037 kunmap_skb_frag(vaddr);
1039 if ((len -= copy) == 0)
1047 if (skb_shinfo(skb)->frag_list) {
1048 struct sk_buff *list = skb_shinfo(skb)->frag_list;
1050 for (; list; list = list->next) {
1053 BUG_TRAP(start <= offset + len);
1055 end = start + list->len;
1056 if ((copy = end - offset) > 0) {
1059 if (skb_copy_bits(list, offset - start,
1062 if ((len -= copy) == 0)
1078 * skb_store_bits - store bits from kernel buffer to skb
1079 * @skb: destination buffer
1080 * @offset: offset in destination
1081 * @from: source buffer
1082 * @len: number of bytes to copy
1084 * Copy the specified number of bytes from the source buffer to the
1085 * destination skb. This function handles all the messy bits of
1086 * traversing fragment lists and such.
1089 int skb_store_bits(const struct sk_buff *skb, int offset, void *from, int len)
1092 int start = skb_headlen(skb);
1094 if (offset > (int)skb->len - len)
1097 if ((copy = start - offset) > 0) {
1100 memcpy(skb->data + offset, from, copy);
1101 if ((len -= copy) == 0)
1107 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
1108 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
1111 BUG_TRAP(start <= offset + len);
1113 end = start + frag->size;
1114 if ((copy = end - offset) > 0) {
1120 vaddr = kmap_skb_frag(frag);
1121 memcpy(vaddr + frag->page_offset + offset - start,
1123 kunmap_skb_frag(vaddr);
1125 if ((len -= copy) == 0)
1133 if (skb_shinfo(skb)->frag_list) {
1134 struct sk_buff *list = skb_shinfo(skb)->frag_list;
1136 for (; list; list = list->next) {
1139 BUG_TRAP(start <= offset + len);
1141 end = start + list->len;
1142 if ((copy = end - offset) > 0) {
1145 if (skb_store_bits(list, offset - start,
1148 if ((len -= copy) == 0)
1163 EXPORT_SYMBOL(skb_store_bits);
1165 /* Checksum skb data. */
1167 __wsum skb_checksum(const struct sk_buff *skb, int offset,
1168 int len, __wsum csum)
1170 int start = skb_headlen(skb);
1171 int i, copy = start - offset;
1174 /* Checksum header. */
1178 csum = csum_partial(skb->data + offset, copy, csum);
1179 if ((len -= copy) == 0)
1185 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
1188 BUG_TRAP(start <= offset + len);
1190 end = start + skb_shinfo(skb)->frags[i].size;
1191 if ((copy = end - offset) > 0) {
1194 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
1198 vaddr = kmap_skb_frag(frag);
1199 csum2 = csum_partial(vaddr + frag->page_offset +
1200 offset - start, copy, 0);
1201 kunmap_skb_frag(vaddr);
1202 csum = csum_block_add(csum, csum2, pos);
1211 if (skb_shinfo(skb)->frag_list) {
1212 struct sk_buff *list = skb_shinfo(skb)->frag_list;
1214 for (; list; list = list->next) {
1217 BUG_TRAP(start <= offset + len);
1219 end = start + list->len;
1220 if ((copy = end - offset) > 0) {
1224 csum2 = skb_checksum(list, offset - start,
1226 csum = csum_block_add(csum, csum2, pos);
1227 if ((len -= copy) == 0)
1240 /* Both of above in one bottle. */
1242 __wsum skb_copy_and_csum_bits(const struct sk_buff *skb, int offset,
1243 u8 *to, int len, __wsum csum)
1245 int start = skb_headlen(skb);
1246 int i, copy = start - offset;
1253 csum = csum_partial_copy_nocheck(skb->data + offset, to,
1255 if ((len -= copy) == 0)
1262 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
1265 BUG_TRAP(start <= offset + len);
1267 end = start + skb_shinfo(skb)->frags[i].size;
1268 if ((copy = end - offset) > 0) {
1271 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
1275 vaddr = kmap_skb_frag(frag);
1276 csum2 = csum_partial_copy_nocheck(vaddr +
1280 kunmap_skb_frag(vaddr);
1281 csum = csum_block_add(csum, csum2, pos);
1291 if (skb_shinfo(skb)->frag_list) {
1292 struct sk_buff *list = skb_shinfo(skb)->frag_list;
1294 for (; list; list = list->next) {
1298 BUG_TRAP(start <= offset + len);
1300 end = start + list->len;
1301 if ((copy = end - offset) > 0) {
1304 csum2 = skb_copy_and_csum_bits(list,
1307 csum = csum_block_add(csum, csum2, pos);
1308 if ((len -= copy) == 0)
1321 void skb_copy_and_csum_dev(const struct sk_buff *skb, u8 *to)
1326 if (skb->ip_summed == CHECKSUM_PARTIAL)
1327 csstart = skb_transport_offset(skb);
1329 csstart = skb_headlen(skb);
1331 BUG_ON(csstart > skb_headlen(skb));
1333 memcpy(to, skb->data, csstart);
1336 if (csstart != skb->len)
1337 csum = skb_copy_and_csum_bits(skb, csstart, to + csstart,
1338 skb->len - csstart, 0);
1340 if (skb->ip_summed == CHECKSUM_PARTIAL) {
1341 long csstuff = csstart + skb->csum_offset;
1343 *((__sum16 *)(to + csstuff)) = csum_fold(csum);
1348 * skb_dequeue - remove from the head of the queue
1349 * @list: list to dequeue from
1351 * Remove the head of the list. The list lock is taken so the function
1352 * may be used safely with other locking list functions. The head item is
1353 * returned or %NULL if the list is empty.
1356 struct sk_buff *skb_dequeue(struct sk_buff_head *list)
1358 unsigned long flags;
1359 struct sk_buff *result;
1361 spin_lock_irqsave(&list->lock, flags);
1362 result = __skb_dequeue(list);
1363 spin_unlock_irqrestore(&list->lock, flags);
1368 * skb_dequeue_tail - remove from the tail of the queue
1369 * @list: list to dequeue from
1371 * Remove the tail of the list. The list lock is taken so the function
1372 * may be used safely with other locking list functions. The tail item is
1373 * returned or %NULL if the list is empty.
1375 struct sk_buff *skb_dequeue_tail(struct sk_buff_head *list)
1377 unsigned long flags;
1378 struct sk_buff *result;
1380 spin_lock_irqsave(&list->lock, flags);
1381 result = __skb_dequeue_tail(list);
1382 spin_unlock_irqrestore(&list->lock, flags);
1387 * skb_queue_purge - empty a list
1388 * @list: list to empty
1390 * Delete all buffers on an &sk_buff list. Each buffer is removed from
1391 * the list and one reference dropped. This function takes the list
1392 * lock and is atomic with respect to other list locking functions.
1394 void skb_queue_purge(struct sk_buff_head *list)
1396 struct sk_buff *skb;
1397 while ((skb = skb_dequeue(list)) != NULL)
1402 * skb_queue_head - queue a buffer at the list head
1403 * @list: list to use
1404 * @newsk: buffer to queue
1406 * Queue a buffer at the start of the list. This function takes the
1407 * list lock and can be used safely with other locking &sk_buff functions
1410 * A buffer cannot be placed on two lists at the same time.
1412 void skb_queue_head(struct sk_buff_head *list, struct sk_buff *newsk)
1414 unsigned long flags;
1416 spin_lock_irqsave(&list->lock, flags);
1417 __skb_queue_head(list, newsk);
1418 spin_unlock_irqrestore(&list->lock, flags);
1422 * skb_queue_tail - queue a buffer at the list tail
1423 * @list: list to use
1424 * @newsk: buffer to queue
1426 * Queue a buffer at the tail of the list. This function takes the
1427 * list lock and can be used safely with other locking &sk_buff functions
1430 * A buffer cannot be placed on two lists at the same time.
1432 void skb_queue_tail(struct sk_buff_head *list, struct sk_buff *newsk)
1434 unsigned long flags;
1436 spin_lock_irqsave(&list->lock, flags);
1437 __skb_queue_tail(list, newsk);
1438 spin_unlock_irqrestore(&list->lock, flags);
1442 * skb_unlink - remove a buffer from a list
1443 * @skb: buffer to remove
1444 * @list: list to use
1446 * Remove a packet from a list. The list locks are taken and this
1447 * function is atomic with respect to other list locked calls
1449 * You must know what list the SKB is on.
1451 void skb_unlink(struct sk_buff *skb, struct sk_buff_head *list)
1453 unsigned long flags;
1455 spin_lock_irqsave(&list->lock, flags);
1456 __skb_unlink(skb, list);
1457 spin_unlock_irqrestore(&list->lock, flags);
1461 * skb_append - append a buffer
1462 * @old: buffer to insert after
1463 * @newsk: buffer to insert
1464 * @list: list to use
1466 * Place a packet after a given packet in a list. The list locks are taken
1467 * and this function is atomic with respect to other list locked calls.
1468 * A buffer cannot be placed on two lists at the same time.
1470 void skb_append(struct sk_buff *old, struct sk_buff *newsk, struct sk_buff_head *list)
1472 unsigned long flags;
1474 spin_lock_irqsave(&list->lock, flags);
1475 __skb_append(old, newsk, list);
1476 spin_unlock_irqrestore(&list->lock, flags);
1481 * skb_insert - insert a buffer
1482 * @old: buffer to insert before
1483 * @newsk: buffer to insert
1484 * @list: list to use
1486 * Place a packet before a given packet in a list. The list locks are
1487 * taken and this function is atomic with respect to other list locked
1490 * A buffer cannot be placed on two lists at the same time.
1492 void skb_insert(struct sk_buff *old, struct sk_buff *newsk, struct sk_buff_head *list)
1494 unsigned long flags;
1496 spin_lock_irqsave(&list->lock, flags);
1497 __skb_insert(newsk, old->prev, old, list);
1498 spin_unlock_irqrestore(&list->lock, flags);
1503 * Tune the memory allocator for a new MTU size.
1505 void skb_add_mtu(int mtu)
1507 /* Must match allocation in alloc_skb */
1508 mtu = SKB_DATA_ALIGN(mtu) + sizeof(struct skb_shared_info);
1510 kmem_add_cache_size(mtu);
1514 static inline void skb_split_inside_header(struct sk_buff *skb,
1515 struct sk_buff* skb1,
1516 const u32 len, const int pos)
1520 memcpy(skb_put(skb1, pos - len), skb->data + len, pos - len);
1522 /* And move data appendix as is. */
1523 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
1524 skb_shinfo(skb1)->frags[i] = skb_shinfo(skb)->frags[i];
1526 skb_shinfo(skb1)->nr_frags = skb_shinfo(skb)->nr_frags;
1527 skb_shinfo(skb)->nr_frags = 0;
1528 skb1->data_len = skb->data_len;
1529 skb1->len += skb1->data_len;
1532 skb->tail = skb->data + len;
1535 static inline void skb_split_no_header(struct sk_buff *skb,
1536 struct sk_buff* skb1,
1537 const u32 len, int pos)
1540 const int nfrags = skb_shinfo(skb)->nr_frags;
1542 skb_shinfo(skb)->nr_frags = 0;
1543 skb1->len = skb1->data_len = skb->len - len;
1545 skb->data_len = len - pos;
1547 for (i = 0; i < nfrags; i++) {
1548 int size = skb_shinfo(skb)->frags[i].size;
1550 if (pos + size > len) {
1551 skb_shinfo(skb1)->frags[k] = skb_shinfo(skb)->frags[i];
1555 * We have two variants in this case:
1556 * 1. Move all the frag to the second
1557 * part, if it is possible. F.e.
1558 * this approach is mandatory for TUX,
1559 * where splitting is expensive.
1560 * 2. Split is accurately. We make this.
1562 get_page(skb_shinfo(skb)->frags[i].page);
1563 skb_shinfo(skb1)->frags[0].page_offset += len - pos;
1564 skb_shinfo(skb1)->frags[0].size -= len - pos;
1565 skb_shinfo(skb)->frags[i].size = len - pos;
1566 skb_shinfo(skb)->nr_frags++;
1570 skb_shinfo(skb)->nr_frags++;
1573 skb_shinfo(skb1)->nr_frags = k;
1577 * skb_split - Split fragmented skb to two parts at length len.
1578 * @skb: the buffer to split
1579 * @skb1: the buffer to receive the second part
1580 * @len: new length for skb
1582 void skb_split(struct sk_buff *skb, struct sk_buff *skb1, const u32 len)
1584 int pos = skb_headlen(skb);
1586 if (len < pos) /* Split line is inside header. */
1587 skb_split_inside_header(skb, skb1, len, pos);
1588 else /* Second chunk has no header, nothing to copy. */
1589 skb_split_no_header(skb, skb1, len, pos);
1593 * skb_prepare_seq_read - Prepare a sequential read of skb data
1594 * @skb: the buffer to read
1595 * @from: lower offset of data to be read
1596 * @to: upper offset of data to be read
1597 * @st: state variable
1599 * Initializes the specified state variable. Must be called before
1600 * invoking skb_seq_read() for the first time.
1602 void skb_prepare_seq_read(struct sk_buff *skb, unsigned int from,
1603 unsigned int to, struct skb_seq_state *st)
1605 st->lower_offset = from;
1606 st->upper_offset = to;
1607 st->root_skb = st->cur_skb = skb;
1608 st->frag_idx = st->stepped_offset = 0;
1609 st->frag_data = NULL;
1613 * skb_seq_read - Sequentially read skb data
1614 * @consumed: number of bytes consumed by the caller so far
1615 * @data: destination pointer for data to be returned
1616 * @st: state variable
1618 * Reads a block of skb data at &consumed relative to the
1619 * lower offset specified to skb_prepare_seq_read(). Assigns
1620 * the head of the data block to &data and returns the length
1621 * of the block or 0 if the end of the skb data or the upper
1622 * offset has been reached.
1624 * The caller is not required to consume all of the data
1625 * returned, i.e. &consumed is typically set to the number
1626 * of bytes already consumed and the next call to
1627 * skb_seq_read() will return the remaining part of the block.
1629 * Note: The size of each block of data returned can be arbitary,
1630 * this limitation is the cost for zerocopy seqeuental
1631 * reads of potentially non linear data.
1633 * Note: Fragment lists within fragments are not implemented
1634 * at the moment, state->root_skb could be replaced with
1635 * a stack for this purpose.
1637 unsigned int skb_seq_read(unsigned int consumed, const u8 **data,
1638 struct skb_seq_state *st)
1640 unsigned int block_limit, abs_offset = consumed + st->lower_offset;
1643 if (unlikely(abs_offset >= st->upper_offset))
1647 block_limit = skb_headlen(st->cur_skb);
1649 if (abs_offset < block_limit) {
1650 *data = st->cur_skb->data + abs_offset;
1651 return block_limit - abs_offset;
1654 if (st->frag_idx == 0 && !st->frag_data)
1655 st->stepped_offset += skb_headlen(st->cur_skb);
1657 while (st->frag_idx < skb_shinfo(st->cur_skb)->nr_frags) {
1658 frag = &skb_shinfo(st->cur_skb)->frags[st->frag_idx];
1659 block_limit = frag->size + st->stepped_offset;
1661 if (abs_offset < block_limit) {
1663 st->frag_data = kmap_skb_frag(frag);
1665 *data = (u8 *) st->frag_data + frag->page_offset +
1666 (abs_offset - st->stepped_offset);
1668 return block_limit - abs_offset;
1671 if (st->frag_data) {
1672 kunmap_skb_frag(st->frag_data);
1673 st->frag_data = NULL;
1677 st->stepped_offset += frag->size;
1680 if (st->cur_skb->next) {
1681 st->cur_skb = st->cur_skb->next;
1684 } else if (st->root_skb == st->cur_skb &&
1685 skb_shinfo(st->root_skb)->frag_list) {
1686 st->cur_skb = skb_shinfo(st->root_skb)->frag_list;
1694 * skb_abort_seq_read - Abort a sequential read of skb data
1695 * @st: state variable
1697 * Must be called if skb_seq_read() was not called until it
1700 void skb_abort_seq_read(struct skb_seq_state *st)
1703 kunmap_skb_frag(st->frag_data);
1706 #define TS_SKB_CB(state) ((struct skb_seq_state *) &((state)->cb))
1708 static unsigned int skb_ts_get_next_block(unsigned int offset, const u8 **text,
1709 struct ts_config *conf,
1710 struct ts_state *state)
1712 return skb_seq_read(offset, text, TS_SKB_CB(state));
1715 static void skb_ts_finish(struct ts_config *conf, struct ts_state *state)
1717 skb_abort_seq_read(TS_SKB_CB(state));
1721 * skb_find_text - Find a text pattern in skb data
1722 * @skb: the buffer to look in
1723 * @from: search offset
1725 * @config: textsearch configuration
1726 * @state: uninitialized textsearch state variable
1728 * Finds a pattern in the skb data according to the specified
1729 * textsearch configuration. Use textsearch_next() to retrieve
1730 * subsequent occurrences of the pattern. Returns the offset
1731 * to the first occurrence or UINT_MAX if no match was found.
1733 unsigned int skb_find_text(struct sk_buff *skb, unsigned int from,
1734 unsigned int to, struct ts_config *config,
1735 struct ts_state *state)
1739 config->get_next_block = skb_ts_get_next_block;
1740 config->finish = skb_ts_finish;
1742 skb_prepare_seq_read(skb, from, to, TS_SKB_CB(state));
1744 ret = textsearch_find(config, state);
1745 return (ret <= to - from ? ret : UINT_MAX);
1749 * skb_append_datato_frags: - append the user data to a skb
1750 * @sk: sock structure
1751 * @skb: skb structure to be appened with user data.
1752 * @getfrag: call back function to be used for getting the user data
1753 * @from: pointer to user message iov
1754 * @length: length of the iov message
1756 * Description: This procedure append the user data in the fragment part
1757 * of the skb if any page alloc fails user this procedure returns -ENOMEM
1759 int skb_append_datato_frags(struct sock *sk, struct sk_buff *skb,
1760 int (*getfrag)(void *from, char *to, int offset,
1761 int len, int odd, struct sk_buff *skb),
1762 void *from, int length)
1765 skb_frag_t *frag = NULL;
1766 struct page *page = NULL;
1772 /* Return error if we don't have space for new frag */
1773 frg_cnt = skb_shinfo(skb)->nr_frags;
1774 if (frg_cnt >= MAX_SKB_FRAGS)
1777 /* allocate a new page for next frag */
1778 page = alloc_pages(sk->sk_allocation, 0);
1780 /* If alloc_page fails just return failure and caller will
1781 * free previous allocated pages by doing kfree_skb()
1786 /* initialize the next frag */
1787 sk->sk_sndmsg_page = page;
1788 sk->sk_sndmsg_off = 0;
1789 skb_fill_page_desc(skb, frg_cnt, page, 0, 0);
1790 skb->truesize += PAGE_SIZE;
1791 atomic_add(PAGE_SIZE, &sk->sk_wmem_alloc);
1793 /* get the new initialized frag */
1794 frg_cnt = skb_shinfo(skb)->nr_frags;
1795 frag = &skb_shinfo(skb)->frags[frg_cnt - 1];
1797 /* copy the user data to page */
1798 left = PAGE_SIZE - frag->page_offset;
1799 copy = (length > left)? left : length;
1801 ret = getfrag(from, (page_address(frag->page) +
1802 frag->page_offset + frag->size),
1803 offset, copy, 0, skb);
1807 /* copy was successful so update the size parameters */
1808 sk->sk_sndmsg_off += copy;
1811 skb->data_len += copy;
1815 } while (length > 0);
1821 * skb_pull_rcsum - pull skb and update receive checksum
1822 * @skb: buffer to update
1823 * @start: start of data before pull
1824 * @len: length of data pulled
1826 * This function performs an skb_pull on the packet and updates
1827 * update the CHECKSUM_COMPLETE checksum. It should be used on
1828 * receive path processing instead of skb_pull unless you know
1829 * that the checksum difference is zero (e.g., a valid IP header)
1830 * or you are setting ip_summed to CHECKSUM_NONE.
1832 unsigned char *skb_pull_rcsum(struct sk_buff *skb, unsigned int len)
1834 BUG_ON(len > skb->len);
1836 BUG_ON(skb->len < skb->data_len);
1837 skb_postpull_rcsum(skb, skb->data, len);
1838 return skb->data += len;
1841 EXPORT_SYMBOL_GPL(skb_pull_rcsum);
1844 * skb_segment - Perform protocol segmentation on skb.
1845 * @skb: buffer to segment
1846 * @features: features for the output path (see dev->features)
1848 * This function performs segmentation on the given skb. It returns
1849 * the segment at the given position. It returns NULL if there are
1850 * no more segments to generate, or when an error is encountered.
1852 struct sk_buff *skb_segment(struct sk_buff *skb, int features)
1854 struct sk_buff *segs = NULL;
1855 struct sk_buff *tail = NULL;
1856 unsigned int mss = skb_shinfo(skb)->gso_size;
1857 unsigned int doffset = skb->data - skb_mac_header(skb);
1858 unsigned int offset = doffset;
1859 unsigned int headroom;
1861 int sg = features & NETIF_F_SG;
1862 int nfrags = skb_shinfo(skb)->nr_frags;
1867 __skb_push(skb, doffset);
1868 headroom = skb_headroom(skb);
1869 pos = skb_headlen(skb);
1872 struct sk_buff *nskb;
1878 len = skb->len - offset;
1882 hsize = skb_headlen(skb) - offset;
1885 if (hsize > len || !sg)
1888 nskb = alloc_skb(hsize + doffset + headroom, GFP_ATOMIC);
1889 if (unlikely(!nskb))
1898 nskb->dev = skb->dev;
1899 nskb->priority = skb->priority;
1900 nskb->protocol = skb->protocol;
1901 nskb->dst = dst_clone(skb->dst);
1902 memcpy(nskb->cb, skb->cb, sizeof(skb->cb));
1903 nskb->pkt_type = skb->pkt_type;
1904 nskb->mac_len = skb->mac_len;
1906 skb_reserve(nskb, headroom);
1907 skb_reset_mac_header(nskb);
1908 nskb->nh.raw = nskb->data + skb->mac_len;
1909 nskb->h.raw = nskb->nh.raw + (skb->h.raw - skb->nh.raw);
1910 memcpy(skb_put(nskb, doffset), skb->data, doffset);
1913 nskb->csum = skb_copy_and_csum_bits(skb, offset,
1919 frag = skb_shinfo(nskb)->frags;
1922 nskb->ip_summed = CHECKSUM_PARTIAL;
1923 nskb->csum = skb->csum;
1924 memcpy(skb_put(nskb, hsize), skb->data + offset, hsize);
1926 while (pos < offset + len) {
1927 BUG_ON(i >= nfrags);
1929 *frag = skb_shinfo(skb)->frags[i];
1930 get_page(frag->page);
1934 frag->page_offset += offset - pos;
1935 frag->size -= offset - pos;
1940 if (pos + size <= offset + len) {
1944 frag->size -= pos + size - (offset + len);
1951 skb_shinfo(nskb)->nr_frags = k;
1952 nskb->data_len = len - hsize;
1953 nskb->len += nskb->data_len;
1954 nskb->truesize += nskb->data_len;
1955 } while ((offset += len) < skb->len);
1960 while ((skb = segs)) {
1964 return ERR_PTR(err);
1967 EXPORT_SYMBOL_GPL(skb_segment);
1969 void __init skb_init(void)
1971 skbuff_head_cache = kmem_cache_create("skbuff_head_cache",
1972 sizeof(struct sk_buff),
1974 SLAB_HWCACHE_ALIGN|SLAB_PANIC,
1976 skbuff_fclone_cache = kmem_cache_create("skbuff_fclone_cache",
1977 (2*sizeof(struct sk_buff)) +
1980 SLAB_HWCACHE_ALIGN|SLAB_PANIC,
1984 EXPORT_SYMBOL(___pskb_trim);
1985 EXPORT_SYMBOL(__kfree_skb);
1986 EXPORT_SYMBOL(kfree_skb);
1987 EXPORT_SYMBOL(__pskb_pull_tail);
1988 EXPORT_SYMBOL(__alloc_skb);
1989 EXPORT_SYMBOL(__netdev_alloc_skb);
1990 EXPORT_SYMBOL(pskb_copy);
1991 EXPORT_SYMBOL(pskb_expand_head);
1992 EXPORT_SYMBOL(skb_checksum);
1993 EXPORT_SYMBOL(skb_clone);
1994 EXPORT_SYMBOL(skb_clone_fraglist);
1995 EXPORT_SYMBOL(skb_copy);
1996 EXPORT_SYMBOL(skb_copy_and_csum_bits);
1997 EXPORT_SYMBOL(skb_copy_and_csum_dev);
1998 EXPORT_SYMBOL(skb_copy_bits);
1999 EXPORT_SYMBOL(skb_copy_expand);
2000 EXPORT_SYMBOL(skb_over_panic);
2001 EXPORT_SYMBOL(skb_pad);
2002 EXPORT_SYMBOL(skb_realloc_headroom);
2003 EXPORT_SYMBOL(skb_under_panic);
2004 EXPORT_SYMBOL(skb_dequeue);
2005 EXPORT_SYMBOL(skb_dequeue_tail);
2006 EXPORT_SYMBOL(skb_insert);
2007 EXPORT_SYMBOL(skb_queue_purge);
2008 EXPORT_SYMBOL(skb_queue_head);
2009 EXPORT_SYMBOL(skb_queue_tail);
2010 EXPORT_SYMBOL(skb_unlink);
2011 EXPORT_SYMBOL(skb_append);
2012 EXPORT_SYMBOL(skb_split);
2013 EXPORT_SYMBOL(skb_prepare_seq_read);
2014 EXPORT_SYMBOL(skb_seq_read);
2015 EXPORT_SYMBOL(skb_abort_seq_read);
2016 EXPORT_SYMBOL(skb_find_text);
2017 EXPORT_SYMBOL(skb_append_datato_frags);