2 * Routines having to do with the 'struct sk_buff' memory handlers.
4 * Authors: Alan Cox <alan@lxorguk.ukuu.org.uk>
5 * Florian La Roche <rzsfl@rz.uni-sb.de>
8 * Alan Cox : Fixed the worst of the load
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
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).
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.
36 * The functions in this file will not compile correctly with gcc 2.4.x
39 #include <linux/module.h>
40 #include <linux/types.h>
41 #include <linux/kernel.h>
43 #include <linux/interrupt.h>
45 #include <linux/inet.h>
46 #include <linux/slab.h>
47 #include <linux/netdevice.h>
48 #ifdef CONFIG_NET_CLS_ACT
49 #include <net/pkt_sched.h>
51 #include <linux/string.h>
52 #include <linux/skbuff.h>
53 #include <linux/splice.h>
54 #include <linux/cache.h>
55 #include <linux/rtnetlink.h>
56 #include <linux/init.h>
57 #include <linux/scatterlist.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;
73 static void sock_pipe_buf_release(struct pipe_inode_info *pipe,
74 struct pipe_buffer *buf)
76 struct sk_buff *skb = (struct sk_buff *) buf->private;
81 static void sock_pipe_buf_get(struct pipe_inode_info *pipe,
82 struct pipe_buffer *buf)
84 struct sk_buff *skb = (struct sk_buff *) buf->private;
89 static int sock_pipe_buf_steal(struct pipe_inode_info *pipe,
90 struct pipe_buffer *buf)
96 /* Pipe buffer operations for a socket. */
97 static struct pipe_buf_operations sock_pipe_buf_ops = {
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,
108 * Keep out-of-line to prevent kernel bloat.
109 * __builtin_return_address is not used because it is not always
114 * skb_over_panic - private function
119 * Out of line support code for skb_put(). Not user callable.
121 void skb_over_panic(struct sk_buff *skb, int sz, void *here)
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>");
132 * skb_under_panic - private function
137 * Out of line support code for skb_push(). Not user callable.
140 void skb_under_panic(struct sk_buff *skb, int sz, void *here)
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>");
150 void skb_truesize_bug(struct sk_buff *skb)
152 WARN(net_ratelimit(), KERN_ERR "SKB BUG: Invalid truesize (%u) "
153 "len=%u, sizeof(sk_buff)=%Zd\n",
154 skb->truesize, skb->len, sizeof(struct sk_buff));
156 EXPORT_SYMBOL(skb_truesize_bug);
158 /* Allocate a new skbuff. We do this ourselves so we can fill in a few
159 * 'private' fields and also do memory statistics to find all the
165 * __alloc_skb - allocate a network buffer
166 * @size: size to allocate
167 * @gfp_mask: allocation mask
168 * @fclone: allocate from fclone cache instead of head cache
169 * and allocate a cloned (child) skb
170 * @node: numa node to allocate memory on
172 * Allocate a new &sk_buff. The returned buffer has no headroom and a
173 * tail room of size bytes. The object has a reference count of one.
174 * The return is the buffer. On a failure the return is %NULL.
176 * Buffers may only be allocated from interrupts using a @gfp_mask of
179 struct sk_buff *__alloc_skb(unsigned int size, gfp_t gfp_mask,
180 int fclone, int node)
182 struct kmem_cache *cache;
183 struct skb_shared_info *shinfo;
187 cache = fclone ? skbuff_fclone_cache : skbuff_head_cache;
190 skb = kmem_cache_alloc_node(cache, gfp_mask & ~__GFP_DMA, node);
194 size = SKB_DATA_ALIGN(size);
195 data = kmalloc_node_track_caller(size + sizeof(struct skb_shared_info),
201 * Only clear those fields we need to clear, not those that we will
202 * actually initialise below. Hence, don't put any more fields after
203 * the tail pointer in struct sk_buff!
205 memset(skb, 0, offsetof(struct sk_buff, tail));
206 skb->truesize = size + sizeof(struct sk_buff);
207 atomic_set(&skb->users, 1);
210 skb_reset_tail_pointer(skb);
211 skb->end = skb->tail + size;
212 /* make sure we initialize shinfo sequentially */
213 shinfo = skb_shinfo(skb);
214 atomic_set(&shinfo->dataref, 1);
215 shinfo->nr_frags = 0;
216 shinfo->gso_size = 0;
217 shinfo->gso_segs = 0;
218 shinfo->gso_type = 0;
219 shinfo->ip6_frag_id = 0;
220 shinfo->frag_list = NULL;
223 struct sk_buff *child = skb + 1;
224 atomic_t *fclone_ref = (atomic_t *) (child + 1);
226 skb->fclone = SKB_FCLONE_ORIG;
227 atomic_set(fclone_ref, 1);
229 child->fclone = SKB_FCLONE_UNAVAILABLE;
234 kmem_cache_free(cache, skb);
240 * __netdev_alloc_skb - allocate an skbuff for rx on a specific device
241 * @dev: network device to receive on
242 * @length: length to allocate
243 * @gfp_mask: get_free_pages mask, passed to alloc_skb
245 * Allocate a new &sk_buff and assign it a usage count of one. The
246 * buffer has unspecified headroom built in. Users should allocate
247 * the headroom they think they need without accounting for the
248 * built in space. The built in space is used for optimisations.
250 * %NULL is returned if there is no free memory.
252 struct sk_buff *__netdev_alloc_skb(struct net_device *dev,
253 unsigned int length, gfp_t gfp_mask)
255 int node = dev->dev.parent ? dev_to_node(dev->dev.parent) : -1;
258 skb = __alloc_skb(length + NET_SKB_PAD, gfp_mask, 0, node);
260 skb_reserve(skb, NET_SKB_PAD);
266 struct page *__netdev_alloc_page(struct net_device *dev, gfp_t gfp_mask)
268 int node = dev->dev.parent ? dev_to_node(dev->dev.parent) : -1;
271 page = alloc_pages_node(node, gfp_mask, 0);
274 EXPORT_SYMBOL(__netdev_alloc_page);
276 void skb_add_rx_frag(struct sk_buff *skb, int i, struct page *page, int off,
279 skb_fill_page_desc(skb, i, page, off, size);
281 skb->data_len += size;
282 skb->truesize += size;
284 EXPORT_SYMBOL(skb_add_rx_frag);
287 * dev_alloc_skb - allocate an skbuff for receiving
288 * @length: length to allocate
290 * Allocate a new &sk_buff and assign it a usage count of one. The
291 * buffer has unspecified headroom built in. Users should allocate
292 * the headroom they think they need without accounting for the
293 * built in space. The built in space is used for optimisations.
295 * %NULL is returned if there is no free memory. Although this function
296 * allocates memory it can be called from an interrupt.
298 struct sk_buff *dev_alloc_skb(unsigned int length)
301 * There is more code here than it seems:
302 * __dev_alloc_skb is an inline
304 return __dev_alloc_skb(length, GFP_ATOMIC);
306 EXPORT_SYMBOL(dev_alloc_skb);
308 static void skb_drop_list(struct sk_buff **listp)
310 struct sk_buff *list = *listp;
315 struct sk_buff *this = list;
321 static inline void skb_drop_fraglist(struct sk_buff *skb)
323 skb_drop_list(&skb_shinfo(skb)->frag_list);
326 static void skb_clone_fraglist(struct sk_buff *skb)
328 struct sk_buff *list;
330 for (list = skb_shinfo(skb)->frag_list; list; list = list->next)
334 static void skb_release_data(struct sk_buff *skb)
337 !atomic_sub_return(skb->nohdr ? (1 << SKB_DATAREF_SHIFT) + 1 : 1,
338 &skb_shinfo(skb)->dataref)) {
339 if (skb_shinfo(skb)->nr_frags) {
341 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
342 put_page(skb_shinfo(skb)->frags[i].page);
345 if (skb_shinfo(skb)->frag_list)
346 skb_drop_fraglist(skb);
353 * Free an skbuff by memory without cleaning the state.
355 static void kfree_skbmem(struct sk_buff *skb)
357 struct sk_buff *other;
358 atomic_t *fclone_ref;
360 switch (skb->fclone) {
361 case SKB_FCLONE_UNAVAILABLE:
362 kmem_cache_free(skbuff_head_cache, skb);
365 case SKB_FCLONE_ORIG:
366 fclone_ref = (atomic_t *) (skb + 2);
367 if (atomic_dec_and_test(fclone_ref))
368 kmem_cache_free(skbuff_fclone_cache, skb);
371 case SKB_FCLONE_CLONE:
372 fclone_ref = (atomic_t *) (skb + 1);
375 /* The clone portion is available for
376 * fast-cloning again.
378 skb->fclone = SKB_FCLONE_UNAVAILABLE;
380 if (atomic_dec_and_test(fclone_ref))
381 kmem_cache_free(skbuff_fclone_cache, other);
386 static void skb_release_head_state(struct sk_buff *skb)
388 dst_release(skb->dst);
390 secpath_put(skb->sp);
392 if (skb->destructor) {
394 skb->destructor(skb);
396 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
397 nf_conntrack_put(skb->nfct);
398 nf_conntrack_put_reasm(skb->nfct_reasm);
400 #ifdef CONFIG_BRIDGE_NETFILTER
401 nf_bridge_put(skb->nf_bridge);
403 /* XXX: IS this still necessary? - JHS */
404 #ifdef CONFIG_NET_SCHED
406 #ifdef CONFIG_NET_CLS_ACT
412 /* Free everything but the sk_buff shell. */
413 static void skb_release_all(struct sk_buff *skb)
415 skb_release_head_state(skb);
416 skb_release_data(skb);
420 * __kfree_skb - private function
423 * Free an sk_buff. Release anything attached to the buffer.
424 * Clean the state. This is an internal helper function. Users should
425 * always call kfree_skb
428 void __kfree_skb(struct sk_buff *skb)
430 skb_release_all(skb);
435 * kfree_skb - free an sk_buff
436 * @skb: buffer to free
438 * Drop a reference to the buffer and free it if the usage count has
441 void kfree_skb(struct sk_buff *skb)
445 if (likely(atomic_read(&skb->users) == 1))
447 else if (likely(!atomic_dec_and_test(&skb->users)))
453 * skb_recycle_check - check if skb can be reused for receive
455 * @skb_size: minimum receive buffer size
457 * Checks that the skb passed in is not shared or cloned, and
458 * that it is linear and its head portion at least as large as
459 * skb_size so that it can be recycled as a receive buffer.
460 * If these conditions are met, this function does any necessary
461 * reference count dropping and cleans up the skbuff as if it
462 * just came from __alloc_skb().
464 int skb_recycle_check(struct sk_buff *skb, int skb_size)
466 struct skb_shared_info *shinfo;
468 if (skb_is_nonlinear(skb) || skb->fclone != SKB_FCLONE_UNAVAILABLE)
471 skb_size = SKB_DATA_ALIGN(skb_size + NET_SKB_PAD);
472 if (skb_end_pointer(skb) - skb->head < skb_size)
475 if (skb_shared(skb) || skb_cloned(skb))
478 skb_release_head_state(skb);
479 shinfo = skb_shinfo(skb);
480 atomic_set(&shinfo->dataref, 1);
481 shinfo->nr_frags = 0;
482 shinfo->gso_size = 0;
483 shinfo->gso_segs = 0;
484 shinfo->gso_type = 0;
485 shinfo->ip6_frag_id = 0;
486 shinfo->frag_list = NULL;
488 memset(skb, 0, offsetof(struct sk_buff, tail));
489 skb->data = skb->head + NET_SKB_PAD;
490 skb_reset_tail_pointer(skb);
494 EXPORT_SYMBOL(skb_recycle_check);
496 static void __copy_skb_header(struct sk_buff *new, const struct sk_buff *old)
498 new->tstamp = old->tstamp;
500 new->transport_header = old->transport_header;
501 new->network_header = old->network_header;
502 new->mac_header = old->mac_header;
503 new->dst = dst_clone(old->dst);
505 new->sp = secpath_get(old->sp);
507 memcpy(new->cb, old->cb, sizeof(old->cb));
508 new->csum_start = old->csum_start;
509 new->csum_offset = old->csum_offset;
510 new->local_df = old->local_df;
511 new->pkt_type = old->pkt_type;
512 new->ip_summed = old->ip_summed;
513 skb_copy_queue_mapping(new, old);
514 new->priority = old->priority;
515 #if defined(CONFIG_IP_VS) || defined(CONFIG_IP_VS_MODULE)
516 new->ipvs_property = old->ipvs_property;
518 new->protocol = old->protocol;
519 new->mark = old->mark;
521 #if defined(CONFIG_NETFILTER_XT_TARGET_TRACE) || \
522 defined(CONFIG_NETFILTER_XT_TARGET_TRACE_MODULE)
523 new->nf_trace = old->nf_trace;
525 #ifdef CONFIG_NET_SCHED
526 new->tc_index = old->tc_index;
527 #ifdef CONFIG_NET_CLS_ACT
528 new->tc_verd = old->tc_verd;
531 new->vlan_tci = old->vlan_tci;
533 skb_copy_secmark(new, old);
536 static struct sk_buff *__skb_clone(struct sk_buff *n, struct sk_buff *skb)
538 #define C(x) n->x = skb->x
540 n->next = n->prev = NULL;
542 __copy_skb_header(n, skb);
547 n->hdr_len = skb->nohdr ? skb_headroom(skb) : skb->hdr_len;
550 n->destructor = NULL;
557 #if defined(CONFIG_MAC80211) || defined(CONFIG_MAC80211_MODULE)
561 atomic_set(&n->users, 1);
563 atomic_inc(&(skb_shinfo(skb)->dataref));
571 * skb_morph - morph one skb into another
572 * @dst: the skb to receive the contents
573 * @src: the skb to supply the contents
575 * This is identical to skb_clone except that the target skb is
576 * supplied by the user.
578 * The target skb is returned upon exit.
580 struct sk_buff *skb_morph(struct sk_buff *dst, struct sk_buff *src)
582 skb_release_all(dst);
583 return __skb_clone(dst, src);
585 EXPORT_SYMBOL_GPL(skb_morph);
588 * skb_clone - duplicate an sk_buff
589 * @skb: buffer to clone
590 * @gfp_mask: allocation priority
592 * Duplicate an &sk_buff. The new one is not owned by a socket. Both
593 * copies share the same packet data but not structure. The new
594 * buffer has a reference count of 1. If the allocation fails the
595 * function returns %NULL otherwise the new buffer is returned.
597 * If this function is called from an interrupt gfp_mask() must be
601 struct sk_buff *skb_clone(struct sk_buff *skb, gfp_t gfp_mask)
606 if (skb->fclone == SKB_FCLONE_ORIG &&
607 n->fclone == SKB_FCLONE_UNAVAILABLE) {
608 atomic_t *fclone_ref = (atomic_t *) (n + 1);
609 n->fclone = SKB_FCLONE_CLONE;
610 atomic_inc(fclone_ref);
612 n = kmem_cache_alloc(skbuff_head_cache, gfp_mask);
615 n->fclone = SKB_FCLONE_UNAVAILABLE;
618 return __skb_clone(n, skb);
621 static void copy_skb_header(struct sk_buff *new, const struct sk_buff *old)
623 #ifndef NET_SKBUFF_DATA_USES_OFFSET
625 * Shift between the two data areas in bytes
627 unsigned long offset = new->data - old->data;
630 __copy_skb_header(new, old);
632 #ifndef NET_SKBUFF_DATA_USES_OFFSET
633 /* {transport,network,mac}_header are relative to skb->head */
634 new->transport_header += offset;
635 new->network_header += offset;
636 new->mac_header += offset;
638 skb_shinfo(new)->gso_size = skb_shinfo(old)->gso_size;
639 skb_shinfo(new)->gso_segs = skb_shinfo(old)->gso_segs;
640 skb_shinfo(new)->gso_type = skb_shinfo(old)->gso_type;
644 * skb_copy - create private copy of an sk_buff
645 * @skb: buffer to copy
646 * @gfp_mask: allocation priority
648 * Make a copy of both an &sk_buff and its data. This is used when the
649 * caller wishes to modify the data and needs a private copy of the
650 * data to alter. Returns %NULL on failure or the pointer to the buffer
651 * on success. The returned buffer has a reference count of 1.
653 * As by-product this function converts non-linear &sk_buff to linear
654 * one, so that &sk_buff becomes completely private and caller is allowed
655 * to modify all the data of returned buffer. This means that this
656 * function is not recommended for use in circumstances when only
657 * header is going to be modified. Use pskb_copy() instead.
660 struct sk_buff *skb_copy(const struct sk_buff *skb, gfp_t gfp_mask)
662 int headerlen = skb->data - skb->head;
664 * Allocate the copy buffer
667 #ifdef NET_SKBUFF_DATA_USES_OFFSET
668 n = alloc_skb(skb->end + skb->data_len, gfp_mask);
670 n = alloc_skb(skb->end - skb->head + skb->data_len, gfp_mask);
675 /* Set the data pointer */
676 skb_reserve(n, headerlen);
677 /* Set the tail pointer and length */
678 skb_put(n, skb->len);
680 if (skb_copy_bits(skb, -headerlen, n->head, headerlen + skb->len))
683 copy_skb_header(n, skb);
689 * pskb_copy - create copy of an sk_buff with private head.
690 * @skb: buffer to copy
691 * @gfp_mask: allocation priority
693 * Make a copy of both an &sk_buff and part of its data, located
694 * in header. Fragmented data remain shared. This is used when
695 * the caller wishes to modify only header of &sk_buff and needs
696 * private copy of the header to alter. Returns %NULL on failure
697 * or the pointer to the buffer on success.
698 * The returned buffer has a reference count of 1.
701 struct sk_buff *pskb_copy(struct sk_buff *skb, gfp_t gfp_mask)
704 * Allocate the copy buffer
707 #ifdef NET_SKBUFF_DATA_USES_OFFSET
708 n = alloc_skb(skb->end, gfp_mask);
710 n = alloc_skb(skb->end - skb->head, gfp_mask);
715 /* Set the data pointer */
716 skb_reserve(n, skb->data - skb->head);
717 /* Set the tail pointer and length */
718 skb_put(n, skb_headlen(skb));
720 skb_copy_from_linear_data(skb, n->data, n->len);
722 n->truesize += skb->data_len;
723 n->data_len = skb->data_len;
726 if (skb_shinfo(skb)->nr_frags) {
729 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
730 skb_shinfo(n)->frags[i] = skb_shinfo(skb)->frags[i];
731 get_page(skb_shinfo(n)->frags[i].page);
733 skb_shinfo(n)->nr_frags = i;
736 if (skb_shinfo(skb)->frag_list) {
737 skb_shinfo(n)->frag_list = skb_shinfo(skb)->frag_list;
738 skb_clone_fraglist(n);
741 copy_skb_header(n, skb);
747 * pskb_expand_head - reallocate header of &sk_buff
748 * @skb: buffer to reallocate
749 * @nhead: room to add at head
750 * @ntail: room to add at tail
751 * @gfp_mask: allocation priority
753 * Expands (or creates identical copy, if &nhead and &ntail are zero)
754 * header of skb. &sk_buff itself is not changed. &sk_buff MUST have
755 * reference count of 1. Returns zero in the case of success or error,
756 * if expansion failed. In the last case, &sk_buff is not changed.
758 * All the pointers pointing into skb header may change and must be
759 * reloaded after call to this function.
762 int pskb_expand_head(struct sk_buff *skb, int nhead, int ntail,
767 #ifdef NET_SKBUFF_DATA_USES_OFFSET
768 int size = nhead + skb->end + ntail;
770 int size = nhead + (skb->end - skb->head) + ntail;
779 size = SKB_DATA_ALIGN(size);
781 data = kmalloc(size + sizeof(struct skb_shared_info), gfp_mask);
785 /* Copy only real data... and, alas, header. This should be
786 * optimized for the cases when header is void. */
787 #ifdef NET_SKBUFF_DATA_USES_OFFSET
788 memcpy(data + nhead, skb->head, skb->tail);
790 memcpy(data + nhead, skb->head, skb->tail - skb->head);
792 memcpy(data + size, skb_end_pointer(skb),
793 sizeof(struct skb_shared_info));
795 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
796 get_page(skb_shinfo(skb)->frags[i].page);
798 if (skb_shinfo(skb)->frag_list)
799 skb_clone_fraglist(skb);
801 skb_release_data(skb);
803 off = (data + nhead) - skb->head;
807 #ifdef NET_SKBUFF_DATA_USES_OFFSET
811 skb->end = skb->head + size;
813 /* {transport,network,mac}_header and tail are relative to skb->head */
815 skb->transport_header += off;
816 skb->network_header += off;
817 skb->mac_header += off;
818 skb->csum_start += nhead;
822 atomic_set(&skb_shinfo(skb)->dataref, 1);
829 /* Make private copy of skb with writable head and some headroom */
831 struct sk_buff *skb_realloc_headroom(struct sk_buff *skb, unsigned int headroom)
833 struct sk_buff *skb2;
834 int delta = headroom - skb_headroom(skb);
837 skb2 = pskb_copy(skb, GFP_ATOMIC);
839 skb2 = skb_clone(skb, GFP_ATOMIC);
840 if (skb2 && pskb_expand_head(skb2, SKB_DATA_ALIGN(delta), 0,
851 * skb_copy_expand - copy and expand sk_buff
852 * @skb: buffer to copy
853 * @newheadroom: new free bytes at head
854 * @newtailroom: new free bytes at tail
855 * @gfp_mask: allocation priority
857 * Make a copy of both an &sk_buff and its data and while doing so
858 * allocate additional space.
860 * This is used when the caller wishes to modify the data and needs a
861 * private copy of the data to alter as well as more space for new fields.
862 * Returns %NULL on failure or the pointer to the buffer
863 * on success. The returned buffer has a reference count of 1.
865 * You must pass %GFP_ATOMIC as the allocation priority if this function
866 * is called from an interrupt.
868 struct sk_buff *skb_copy_expand(const struct sk_buff *skb,
869 int newheadroom, int newtailroom,
873 * Allocate the copy buffer
875 struct sk_buff *n = alloc_skb(newheadroom + skb->len + newtailroom,
877 int oldheadroom = skb_headroom(skb);
878 int head_copy_len, head_copy_off;
884 skb_reserve(n, newheadroom);
886 /* Set the tail pointer and length */
887 skb_put(n, skb->len);
889 head_copy_len = oldheadroom;
891 if (newheadroom <= head_copy_len)
892 head_copy_len = newheadroom;
894 head_copy_off = newheadroom - head_copy_len;
896 /* Copy the linear header and data. */
897 if (skb_copy_bits(skb, -head_copy_len, n->head + head_copy_off,
898 skb->len + head_copy_len))
901 copy_skb_header(n, skb);
903 off = newheadroom - oldheadroom;
904 n->csum_start += off;
905 #ifdef NET_SKBUFF_DATA_USES_OFFSET
906 n->transport_header += off;
907 n->network_header += off;
908 n->mac_header += off;
915 * skb_pad - zero pad the tail of an skb
916 * @skb: buffer to pad
919 * Ensure that a buffer is followed by a padding area that is zero
920 * filled. Used by network drivers which may DMA or transfer data
921 * beyond the buffer end onto the wire.
923 * May return error in out of memory cases. The skb is freed on error.
926 int skb_pad(struct sk_buff *skb, int pad)
931 /* If the skbuff is non linear tailroom is always zero.. */
932 if (!skb_cloned(skb) && skb_tailroom(skb) >= pad) {
933 memset(skb->data+skb->len, 0, pad);
937 ntail = skb->data_len + pad - (skb->end - skb->tail);
938 if (likely(skb_cloned(skb) || ntail > 0)) {
939 err = pskb_expand_head(skb, 0, ntail, GFP_ATOMIC);
944 /* FIXME: The use of this function with non-linear skb's really needs
947 err = skb_linearize(skb);
951 memset(skb->data + skb->len, 0, pad);
960 * skb_put - add data to a buffer
961 * @skb: buffer to use
962 * @len: amount of data to add
964 * This function extends the used data area of the buffer. If this would
965 * exceed the total buffer size the kernel will panic. A pointer to the
966 * first byte of the extra data is returned.
968 unsigned char *skb_put(struct sk_buff *skb, unsigned int len)
970 unsigned char *tmp = skb_tail_pointer(skb);
971 SKB_LINEAR_ASSERT(skb);
974 if (unlikely(skb->tail > skb->end))
975 skb_over_panic(skb, len, __builtin_return_address(0));
978 EXPORT_SYMBOL(skb_put);
981 * skb_push - add data to the start of a buffer
982 * @skb: buffer to use
983 * @len: amount of data to add
985 * This function extends the used data area of the buffer at the buffer
986 * start. If this would exceed the total buffer headroom the kernel will
987 * panic. A pointer to the first byte of the extra data is returned.
989 unsigned char *skb_push(struct sk_buff *skb, unsigned int len)
993 if (unlikely(skb->data<skb->head))
994 skb_under_panic(skb, len, __builtin_return_address(0));
997 EXPORT_SYMBOL(skb_push);
1000 * skb_pull - remove data from the start of a buffer
1001 * @skb: buffer to use
1002 * @len: amount of data to remove
1004 * This function removes data from the start of a buffer, returning
1005 * the memory to the headroom. A pointer to the next data in the buffer
1006 * is returned. Once the data has been pulled future pushes will overwrite
1009 unsigned char *skb_pull(struct sk_buff *skb, unsigned int len)
1011 return unlikely(len > skb->len) ? NULL : __skb_pull(skb, len);
1013 EXPORT_SYMBOL(skb_pull);
1016 * skb_trim - remove end from a buffer
1017 * @skb: buffer to alter
1020 * Cut the length of a buffer down by removing data from the tail. If
1021 * the buffer is already under the length specified it is not modified.
1022 * The skb must be linear.
1024 void skb_trim(struct sk_buff *skb, unsigned int len)
1027 __skb_trim(skb, len);
1029 EXPORT_SYMBOL(skb_trim);
1031 /* Trims skb to length len. It can change skb pointers.
1034 int ___pskb_trim(struct sk_buff *skb, unsigned int len)
1036 struct sk_buff **fragp;
1037 struct sk_buff *frag;
1038 int offset = skb_headlen(skb);
1039 int nfrags = skb_shinfo(skb)->nr_frags;
1043 if (skb_cloned(skb) &&
1044 unlikely((err = pskb_expand_head(skb, 0, 0, GFP_ATOMIC))))
1051 for (; i < nfrags; i++) {
1052 int end = offset + skb_shinfo(skb)->frags[i].size;
1059 skb_shinfo(skb)->frags[i++].size = len - offset;
1062 skb_shinfo(skb)->nr_frags = i;
1064 for (; i < nfrags; i++)
1065 put_page(skb_shinfo(skb)->frags[i].page);
1067 if (skb_shinfo(skb)->frag_list)
1068 skb_drop_fraglist(skb);
1072 for (fragp = &skb_shinfo(skb)->frag_list; (frag = *fragp);
1073 fragp = &frag->next) {
1074 int end = offset + frag->len;
1076 if (skb_shared(frag)) {
1077 struct sk_buff *nfrag;
1079 nfrag = skb_clone(frag, GFP_ATOMIC);
1080 if (unlikely(!nfrag))
1083 nfrag->next = frag->next;
1095 unlikely((err = pskb_trim(frag, len - offset))))
1099 skb_drop_list(&frag->next);
1104 if (len > skb_headlen(skb)) {
1105 skb->data_len -= skb->len - len;
1110 skb_set_tail_pointer(skb, len);
1117 * __pskb_pull_tail - advance tail of skb header
1118 * @skb: buffer to reallocate
1119 * @delta: number of bytes to advance tail
1121 * The function makes a sense only on a fragmented &sk_buff,
1122 * it expands header moving its tail forward and copying necessary
1123 * data from fragmented part.
1125 * &sk_buff MUST have reference count of 1.
1127 * Returns %NULL (and &sk_buff does not change) if pull failed
1128 * or value of new tail of skb in the case of success.
1130 * All the pointers pointing into skb header may change and must be
1131 * reloaded after call to this function.
1134 /* Moves tail of skb head forward, copying data from fragmented part,
1135 * when it is necessary.
1136 * 1. It may fail due to malloc failure.
1137 * 2. It may change skb pointers.
1139 * It is pretty complicated. Luckily, it is called only in exceptional cases.
1141 unsigned char *__pskb_pull_tail(struct sk_buff *skb, int delta)
1143 /* If skb has not enough free space at tail, get new one
1144 * plus 128 bytes for future expansions. If we have enough
1145 * room at tail, reallocate without expansion only if skb is cloned.
1147 int i, k, eat = (skb->tail + delta) - skb->end;
1149 if (eat > 0 || skb_cloned(skb)) {
1150 if (pskb_expand_head(skb, 0, eat > 0 ? eat + 128 : 0,
1155 if (skb_copy_bits(skb, skb_headlen(skb), skb_tail_pointer(skb), delta))
1158 /* Optimization: no fragments, no reasons to preestimate
1159 * size of pulled pages. Superb.
1161 if (!skb_shinfo(skb)->frag_list)
1164 /* Estimate size of pulled pages. */
1166 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
1167 if (skb_shinfo(skb)->frags[i].size >= eat)
1169 eat -= skb_shinfo(skb)->frags[i].size;
1172 /* If we need update frag list, we are in troubles.
1173 * Certainly, it possible to add an offset to skb data,
1174 * but taking into account that pulling is expected to
1175 * be very rare operation, it is worth to fight against
1176 * further bloating skb head and crucify ourselves here instead.
1177 * Pure masohism, indeed. 8)8)
1180 struct sk_buff *list = skb_shinfo(skb)->frag_list;
1181 struct sk_buff *clone = NULL;
1182 struct sk_buff *insp = NULL;
1187 if (list->len <= eat) {
1188 /* Eaten as whole. */
1193 /* Eaten partially. */
1195 if (skb_shared(list)) {
1196 /* Sucks! We need to fork list. :-( */
1197 clone = skb_clone(list, GFP_ATOMIC);
1203 /* This may be pulled without
1207 if (!pskb_pull(list, eat)) {
1216 /* Free pulled out fragments. */
1217 while ((list = skb_shinfo(skb)->frag_list) != insp) {
1218 skb_shinfo(skb)->frag_list = list->next;
1221 /* And insert new clone at head. */
1224 skb_shinfo(skb)->frag_list = clone;
1227 /* Success! Now we may commit changes to skb data. */
1232 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
1233 if (skb_shinfo(skb)->frags[i].size <= eat) {
1234 put_page(skb_shinfo(skb)->frags[i].page);
1235 eat -= skb_shinfo(skb)->frags[i].size;
1237 skb_shinfo(skb)->frags[k] = skb_shinfo(skb)->frags[i];
1239 skb_shinfo(skb)->frags[k].page_offset += eat;
1240 skb_shinfo(skb)->frags[k].size -= eat;
1246 skb_shinfo(skb)->nr_frags = k;
1249 skb->data_len -= delta;
1251 return skb_tail_pointer(skb);
1254 /* Copy some data bits from skb to kernel buffer. */
1256 int skb_copy_bits(const struct sk_buff *skb, int offset, void *to, int len)
1259 int start = skb_headlen(skb);
1261 if (offset > (int)skb->len - len)
1265 if ((copy = start - offset) > 0) {
1268 skb_copy_from_linear_data_offset(skb, offset, to, copy);
1269 if ((len -= copy) == 0)
1275 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
1278 WARN_ON(start > offset + len);
1280 end = start + skb_shinfo(skb)->frags[i].size;
1281 if ((copy = end - offset) > 0) {
1287 vaddr = kmap_skb_frag(&skb_shinfo(skb)->frags[i]);
1289 vaddr + skb_shinfo(skb)->frags[i].page_offset+
1290 offset - start, copy);
1291 kunmap_skb_frag(vaddr);
1293 if ((len -= copy) == 0)
1301 if (skb_shinfo(skb)->frag_list) {
1302 struct sk_buff *list = skb_shinfo(skb)->frag_list;
1304 for (; list; list = list->next) {
1307 WARN_ON(start > offset + len);
1309 end = start + list->len;
1310 if ((copy = end - offset) > 0) {
1313 if (skb_copy_bits(list, offset - start,
1316 if ((len -= copy) == 0)
1332 * Callback from splice_to_pipe(), if we need to release some pages
1333 * at the end of the spd in case we error'ed out in filling the pipe.
1335 static void sock_spd_release(struct splice_pipe_desc *spd, unsigned int i)
1337 struct sk_buff *skb = (struct sk_buff *) spd->partial[i].private;
1343 * Fill page/offset/length into spd, if it can hold more pages.
1345 static inline int spd_fill_page(struct splice_pipe_desc *spd, struct page *page,
1346 unsigned int len, unsigned int offset,
1347 struct sk_buff *skb)
1349 if (unlikely(spd->nr_pages == PIPE_BUFFERS))
1352 spd->pages[spd->nr_pages] = page;
1353 spd->partial[spd->nr_pages].len = len;
1354 spd->partial[spd->nr_pages].offset = offset;
1355 spd->partial[spd->nr_pages].private = (unsigned long) skb_get(skb);
1360 static inline void __segment_seek(struct page **page, unsigned int *poff,
1361 unsigned int *plen, unsigned int off)
1364 *page += *poff / PAGE_SIZE;
1365 *poff = *poff % PAGE_SIZE;
1369 static inline int __splice_segment(struct page *page, unsigned int poff,
1370 unsigned int plen, unsigned int *off,
1371 unsigned int *len, struct sk_buff *skb,
1372 struct splice_pipe_desc *spd)
1377 /* skip this segment if already processed */
1383 /* ignore any bits we already processed */
1385 __segment_seek(&page, &poff, &plen, *off);
1390 unsigned int flen = min(*len, plen);
1392 /* the linear region may spread across several pages */
1393 flen = min_t(unsigned int, flen, PAGE_SIZE - poff);
1395 if (spd_fill_page(spd, page, flen, poff, skb))
1398 __segment_seek(&page, &poff, &plen, flen);
1401 } while (*len && plen);
1407 * Map linear and fragment data from the skb to spd. It reports failure if the
1408 * pipe is full or if we already spliced the requested length.
1410 static int __skb_splice_bits(struct sk_buff *skb, unsigned int *offset,
1412 struct splice_pipe_desc *spd)
1417 * map the linear part
1419 if (__splice_segment(virt_to_page(skb->data),
1420 (unsigned long) skb->data & (PAGE_SIZE - 1),
1422 offset, len, skb, spd))
1426 * then map the fragments
1428 for (seg = 0; seg < skb_shinfo(skb)->nr_frags; seg++) {
1429 const skb_frag_t *f = &skb_shinfo(skb)->frags[seg];
1431 if (__splice_segment(f->page, f->page_offset, f->size,
1432 offset, len, skb, spd))
1440 * Map data from the skb to a pipe. Should handle both the linear part,
1441 * the fragments, and the frag list. It does NOT handle frag lists within
1442 * the frag list, if such a thing exists. We'd probably need to recurse to
1443 * handle that cleanly.
1445 int skb_splice_bits(struct sk_buff *__skb, unsigned int offset,
1446 struct pipe_inode_info *pipe, unsigned int tlen,
1449 struct partial_page partial[PIPE_BUFFERS];
1450 struct page *pages[PIPE_BUFFERS];
1451 struct splice_pipe_desc spd = {
1455 .ops = &sock_pipe_buf_ops,
1456 .spd_release = sock_spd_release,
1458 struct sk_buff *skb;
1461 * I'd love to avoid the clone here, but tcp_read_sock()
1462 * ignores reference counts and unconditonally kills the sk_buff
1463 * on return from the actor.
1465 skb = skb_clone(__skb, GFP_KERNEL);
1470 * __skb_splice_bits() only fails if the output has no room left,
1471 * so no point in going over the frag_list for the error case.
1473 if (__skb_splice_bits(skb, &offset, &tlen, &spd))
1479 * now see if we have a frag_list to map
1481 if (skb_shinfo(skb)->frag_list) {
1482 struct sk_buff *list = skb_shinfo(skb)->frag_list;
1484 for (; list && tlen; list = list->next) {
1485 if (__skb_splice_bits(list, &offset, &tlen, &spd))
1492 * drop our reference to the clone, the pipe consumption will
1499 struct sock *sk = __skb->sk;
1502 * Drop the socket lock, otherwise we have reverse
1503 * locking dependencies between sk_lock and i_mutex
1504 * here as compared to sendfile(). We enter here
1505 * with the socket lock held, and splice_to_pipe() will
1506 * grab the pipe inode lock. For sendfile() emulation,
1507 * we call into ->sendpage() with the i_mutex lock held
1508 * and networking will grab the socket lock.
1511 ret = splice_to_pipe(pipe, &spd);
1520 * skb_store_bits - store bits from kernel buffer to skb
1521 * @skb: destination buffer
1522 * @offset: offset in destination
1523 * @from: source buffer
1524 * @len: number of bytes to copy
1526 * Copy the specified number of bytes from the source buffer to the
1527 * destination skb. This function handles all the messy bits of
1528 * traversing fragment lists and such.
1531 int skb_store_bits(struct sk_buff *skb, int offset, const void *from, int len)
1534 int start = skb_headlen(skb);
1536 if (offset > (int)skb->len - len)
1539 if ((copy = start - offset) > 0) {
1542 skb_copy_to_linear_data_offset(skb, offset, from, copy);
1543 if ((len -= copy) == 0)
1549 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
1550 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
1553 WARN_ON(start > offset + len);
1555 end = start + frag->size;
1556 if ((copy = end - offset) > 0) {
1562 vaddr = kmap_skb_frag(frag);
1563 memcpy(vaddr + frag->page_offset + offset - start,
1565 kunmap_skb_frag(vaddr);
1567 if ((len -= copy) == 0)
1575 if (skb_shinfo(skb)->frag_list) {
1576 struct sk_buff *list = skb_shinfo(skb)->frag_list;
1578 for (; list; list = list->next) {
1581 WARN_ON(start > offset + len);
1583 end = start + list->len;
1584 if ((copy = end - offset) > 0) {
1587 if (skb_store_bits(list, offset - start,
1590 if ((len -= copy) == 0)
1605 EXPORT_SYMBOL(skb_store_bits);
1607 /* Checksum skb data. */
1609 __wsum skb_checksum(const struct sk_buff *skb, int offset,
1610 int len, __wsum csum)
1612 int start = skb_headlen(skb);
1613 int i, copy = start - offset;
1616 /* Checksum header. */
1620 csum = csum_partial(skb->data + offset, copy, csum);
1621 if ((len -= copy) == 0)
1627 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
1630 WARN_ON(start > offset + len);
1632 end = start + skb_shinfo(skb)->frags[i].size;
1633 if ((copy = end - offset) > 0) {
1636 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
1640 vaddr = kmap_skb_frag(frag);
1641 csum2 = csum_partial(vaddr + frag->page_offset +
1642 offset - start, copy, 0);
1643 kunmap_skb_frag(vaddr);
1644 csum = csum_block_add(csum, csum2, pos);
1653 if (skb_shinfo(skb)->frag_list) {
1654 struct sk_buff *list = skb_shinfo(skb)->frag_list;
1656 for (; list; list = list->next) {
1659 WARN_ON(start > offset + len);
1661 end = start + list->len;
1662 if ((copy = end - offset) > 0) {
1666 csum2 = skb_checksum(list, offset - start,
1668 csum = csum_block_add(csum, csum2, pos);
1669 if ((len -= copy) == 0)
1682 /* Both of above in one bottle. */
1684 __wsum skb_copy_and_csum_bits(const struct sk_buff *skb, int offset,
1685 u8 *to, int len, __wsum csum)
1687 int start = skb_headlen(skb);
1688 int i, copy = start - offset;
1695 csum = csum_partial_copy_nocheck(skb->data + offset, to,
1697 if ((len -= copy) == 0)
1704 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
1707 WARN_ON(start > offset + len);
1709 end = start + skb_shinfo(skb)->frags[i].size;
1710 if ((copy = end - offset) > 0) {
1713 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
1717 vaddr = kmap_skb_frag(frag);
1718 csum2 = csum_partial_copy_nocheck(vaddr +
1722 kunmap_skb_frag(vaddr);
1723 csum = csum_block_add(csum, csum2, pos);
1733 if (skb_shinfo(skb)->frag_list) {
1734 struct sk_buff *list = skb_shinfo(skb)->frag_list;
1736 for (; list; list = list->next) {
1740 WARN_ON(start > offset + len);
1742 end = start + list->len;
1743 if ((copy = end - offset) > 0) {
1746 csum2 = skb_copy_and_csum_bits(list,
1749 csum = csum_block_add(csum, csum2, pos);
1750 if ((len -= copy) == 0)
1763 void skb_copy_and_csum_dev(const struct sk_buff *skb, u8 *to)
1768 if (skb->ip_summed == CHECKSUM_PARTIAL)
1769 csstart = skb->csum_start - skb_headroom(skb);
1771 csstart = skb_headlen(skb);
1773 BUG_ON(csstart > skb_headlen(skb));
1775 skb_copy_from_linear_data(skb, to, csstart);
1778 if (csstart != skb->len)
1779 csum = skb_copy_and_csum_bits(skb, csstart, to + csstart,
1780 skb->len - csstart, 0);
1782 if (skb->ip_summed == CHECKSUM_PARTIAL) {
1783 long csstuff = csstart + skb->csum_offset;
1785 *((__sum16 *)(to + csstuff)) = csum_fold(csum);
1790 * skb_dequeue - remove from the head of the queue
1791 * @list: list to dequeue from
1793 * Remove the head of the list. The list lock is taken so the function
1794 * may be used safely with other locking list functions. The head item is
1795 * returned or %NULL if the list is empty.
1798 struct sk_buff *skb_dequeue(struct sk_buff_head *list)
1800 unsigned long flags;
1801 struct sk_buff *result;
1803 spin_lock_irqsave(&list->lock, flags);
1804 result = __skb_dequeue(list);
1805 spin_unlock_irqrestore(&list->lock, flags);
1810 * skb_dequeue_tail - remove from the tail of the queue
1811 * @list: list to dequeue from
1813 * Remove the tail of the list. The list lock is taken so the function
1814 * may be used safely with other locking list functions. The tail item is
1815 * returned or %NULL if the list is empty.
1817 struct sk_buff *skb_dequeue_tail(struct sk_buff_head *list)
1819 unsigned long flags;
1820 struct sk_buff *result;
1822 spin_lock_irqsave(&list->lock, flags);
1823 result = __skb_dequeue_tail(list);
1824 spin_unlock_irqrestore(&list->lock, flags);
1829 * skb_queue_purge - empty a list
1830 * @list: list to empty
1832 * Delete all buffers on an &sk_buff list. Each buffer is removed from
1833 * the list and one reference dropped. This function takes the list
1834 * lock and is atomic with respect to other list locking functions.
1836 void skb_queue_purge(struct sk_buff_head *list)
1838 struct sk_buff *skb;
1839 while ((skb = skb_dequeue(list)) != NULL)
1844 * skb_queue_head - queue a buffer at the list head
1845 * @list: list to use
1846 * @newsk: buffer to queue
1848 * Queue a buffer at the start of the list. This function takes the
1849 * list lock and can be used safely with other locking &sk_buff functions
1852 * A buffer cannot be placed on two lists at the same time.
1854 void skb_queue_head(struct sk_buff_head *list, struct sk_buff *newsk)
1856 unsigned long flags;
1858 spin_lock_irqsave(&list->lock, flags);
1859 __skb_queue_head(list, newsk);
1860 spin_unlock_irqrestore(&list->lock, flags);
1864 * skb_queue_tail - queue a buffer at the list tail
1865 * @list: list to use
1866 * @newsk: buffer to queue
1868 * Queue a buffer at the tail of the list. This function takes the
1869 * list lock and can be used safely with other locking &sk_buff functions
1872 * A buffer cannot be placed on two lists at the same time.
1874 void skb_queue_tail(struct sk_buff_head *list, struct sk_buff *newsk)
1876 unsigned long flags;
1878 spin_lock_irqsave(&list->lock, flags);
1879 __skb_queue_tail(list, newsk);
1880 spin_unlock_irqrestore(&list->lock, flags);
1884 * skb_unlink - remove a buffer from a list
1885 * @skb: buffer to remove
1886 * @list: list to use
1888 * Remove a packet from a list. The list locks are taken and this
1889 * function is atomic with respect to other list locked calls
1891 * You must know what list the SKB is on.
1893 void skb_unlink(struct sk_buff *skb, struct sk_buff_head *list)
1895 unsigned long flags;
1897 spin_lock_irqsave(&list->lock, flags);
1898 __skb_unlink(skb, list);
1899 spin_unlock_irqrestore(&list->lock, flags);
1903 * skb_append - append a buffer
1904 * @old: buffer to insert after
1905 * @newsk: buffer to insert
1906 * @list: list to use
1908 * Place a packet after a given packet in a list. The list locks are taken
1909 * and this function is atomic with respect to other list locked calls.
1910 * A buffer cannot be placed on two lists at the same time.
1912 void skb_append(struct sk_buff *old, struct sk_buff *newsk, struct sk_buff_head *list)
1914 unsigned long flags;
1916 spin_lock_irqsave(&list->lock, flags);
1917 __skb_queue_after(list, old, newsk);
1918 spin_unlock_irqrestore(&list->lock, flags);
1923 * skb_insert - insert a buffer
1924 * @old: buffer to insert before
1925 * @newsk: buffer to insert
1926 * @list: list to use
1928 * Place a packet before a given packet in a list. The list locks are
1929 * taken and this function is atomic with respect to other list locked
1932 * A buffer cannot be placed on two lists at the same time.
1934 void skb_insert(struct sk_buff *old, struct sk_buff *newsk, struct sk_buff_head *list)
1936 unsigned long flags;
1938 spin_lock_irqsave(&list->lock, flags);
1939 __skb_insert(newsk, old->prev, old, list);
1940 spin_unlock_irqrestore(&list->lock, flags);
1943 static inline void skb_split_inside_header(struct sk_buff *skb,
1944 struct sk_buff* skb1,
1945 const u32 len, const int pos)
1949 skb_copy_from_linear_data_offset(skb, len, skb_put(skb1, pos - len),
1951 /* And move data appendix as is. */
1952 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
1953 skb_shinfo(skb1)->frags[i] = skb_shinfo(skb)->frags[i];
1955 skb_shinfo(skb1)->nr_frags = skb_shinfo(skb)->nr_frags;
1956 skb_shinfo(skb)->nr_frags = 0;
1957 skb1->data_len = skb->data_len;
1958 skb1->len += skb1->data_len;
1961 skb_set_tail_pointer(skb, len);
1964 static inline void skb_split_no_header(struct sk_buff *skb,
1965 struct sk_buff* skb1,
1966 const u32 len, int pos)
1969 const int nfrags = skb_shinfo(skb)->nr_frags;
1971 skb_shinfo(skb)->nr_frags = 0;
1972 skb1->len = skb1->data_len = skb->len - len;
1974 skb->data_len = len - pos;
1976 for (i = 0; i < nfrags; i++) {
1977 int size = skb_shinfo(skb)->frags[i].size;
1979 if (pos + size > len) {
1980 skb_shinfo(skb1)->frags[k] = skb_shinfo(skb)->frags[i];
1984 * We have two variants in this case:
1985 * 1. Move all the frag to the second
1986 * part, if it is possible. F.e.
1987 * this approach is mandatory for TUX,
1988 * where splitting is expensive.
1989 * 2. Split is accurately. We make this.
1991 get_page(skb_shinfo(skb)->frags[i].page);
1992 skb_shinfo(skb1)->frags[0].page_offset += len - pos;
1993 skb_shinfo(skb1)->frags[0].size -= len - pos;
1994 skb_shinfo(skb)->frags[i].size = len - pos;
1995 skb_shinfo(skb)->nr_frags++;
1999 skb_shinfo(skb)->nr_frags++;
2002 skb_shinfo(skb1)->nr_frags = k;
2006 * skb_split - Split fragmented skb to two parts at length len.
2007 * @skb: the buffer to split
2008 * @skb1: the buffer to receive the second part
2009 * @len: new length for skb
2011 void skb_split(struct sk_buff *skb, struct sk_buff *skb1, const u32 len)
2013 int pos = skb_headlen(skb);
2015 if (len < pos) /* Split line is inside header. */
2016 skb_split_inside_header(skb, skb1, len, pos);
2017 else /* Second chunk has no header, nothing to copy. */
2018 skb_split_no_header(skb, skb1, len, pos);
2021 /* Shifting from/to a cloned skb is a no-go.
2023 * Caller cannot keep skb_shinfo related pointers past calling here!
2025 static int skb_prepare_for_shift(struct sk_buff *skb)
2027 return skb_cloned(skb) && pskb_expand_head(skb, 0, 0, GFP_ATOMIC);
2031 * skb_shift - Shifts paged data partially from skb to another
2032 * @tgt: buffer into which tail data gets added
2033 * @skb: buffer from which the paged data comes from
2034 * @shiftlen: shift up to this many bytes
2036 * Attempts to shift up to shiftlen worth of bytes, which may be less than
2037 * the length of the skb, from tgt to skb. Returns number bytes shifted.
2038 * It's up to caller to free skb if everything was shifted.
2040 * If @tgt runs out of frags, the whole operation is aborted.
2042 * Skb cannot include anything else but paged data while tgt is allowed
2043 * to have non-paged data as well.
2045 * TODO: full sized shift could be optimized but that would need
2046 * specialized skb free'er to handle frags without up-to-date nr_frags.
2048 int skb_shift(struct sk_buff *tgt, struct sk_buff *skb, int shiftlen)
2050 int from, to, merge, todo;
2051 struct skb_frag_struct *fragfrom, *fragto;
2053 BUG_ON(shiftlen > skb->len);
2054 BUG_ON(skb_headlen(skb)); /* Would corrupt stream */
2058 to = skb_shinfo(tgt)->nr_frags;
2059 fragfrom = &skb_shinfo(skb)->frags[from];
2061 /* Actual merge is delayed until the point when we know we can
2062 * commit all, so that we don't have to undo partial changes
2065 !skb_can_coalesce(tgt, to, fragfrom->page, fragfrom->page_offset)) {
2070 todo -= fragfrom->size;
2072 if (skb_prepare_for_shift(skb) ||
2073 skb_prepare_for_shift(tgt))
2076 /* All previous frag pointers might be stale! */
2077 fragfrom = &skb_shinfo(skb)->frags[from];
2078 fragto = &skb_shinfo(tgt)->frags[merge];
2080 fragto->size += shiftlen;
2081 fragfrom->size -= shiftlen;
2082 fragfrom->page_offset += shiftlen;
2090 /* Skip full, not-fitting skb to avoid expensive operations */
2091 if ((shiftlen == skb->len) &&
2092 (skb_shinfo(skb)->nr_frags - from) > (MAX_SKB_FRAGS - to))
2095 if (skb_prepare_for_shift(skb) || skb_prepare_for_shift(tgt))
2098 while ((todo > 0) && (from < skb_shinfo(skb)->nr_frags)) {
2099 if (to == MAX_SKB_FRAGS)
2102 fragfrom = &skb_shinfo(skb)->frags[from];
2103 fragto = &skb_shinfo(tgt)->frags[to];
2105 if (todo >= fragfrom->size) {
2106 *fragto = *fragfrom;
2107 todo -= fragfrom->size;
2112 get_page(fragfrom->page);
2113 fragto->page = fragfrom->page;
2114 fragto->page_offset = fragfrom->page_offset;
2115 fragto->size = todo;
2117 fragfrom->page_offset += todo;
2118 fragfrom->size -= todo;
2126 /* Ready to "commit" this state change to tgt */
2127 skb_shinfo(tgt)->nr_frags = to;
2130 fragfrom = &skb_shinfo(skb)->frags[0];
2131 fragto = &skb_shinfo(tgt)->frags[merge];
2133 fragto->size += fragfrom->size;
2134 put_page(fragfrom->page);
2137 /* Reposition in the original skb */
2139 while (from < skb_shinfo(skb)->nr_frags)
2140 skb_shinfo(skb)->frags[to++] = skb_shinfo(skb)->frags[from++];
2141 skb_shinfo(skb)->nr_frags = to;
2143 BUG_ON(todo > 0 && !skb_shinfo(skb)->nr_frags);
2146 /* Most likely the tgt won't ever need its checksum anymore, skb on
2147 * the other hand might need it if it needs to be resent
2149 tgt->ip_summed = CHECKSUM_PARTIAL;
2150 skb->ip_summed = CHECKSUM_PARTIAL;
2152 /* Yak, is it really working this way? Some helper please? */
2153 skb->len -= shiftlen;
2154 skb->data_len -= shiftlen;
2155 skb->truesize -= shiftlen;
2156 tgt->len += shiftlen;
2157 tgt->data_len += shiftlen;
2158 tgt->truesize += shiftlen;
2164 * skb_prepare_seq_read - Prepare a sequential read of skb data
2165 * @skb: the buffer to read
2166 * @from: lower offset of data to be read
2167 * @to: upper offset of data to be read
2168 * @st: state variable
2170 * Initializes the specified state variable. Must be called before
2171 * invoking skb_seq_read() for the first time.
2173 void skb_prepare_seq_read(struct sk_buff *skb, unsigned int from,
2174 unsigned int to, struct skb_seq_state *st)
2176 st->lower_offset = from;
2177 st->upper_offset = to;
2178 st->root_skb = st->cur_skb = skb;
2179 st->frag_idx = st->stepped_offset = 0;
2180 st->frag_data = NULL;
2184 * skb_seq_read - Sequentially read skb data
2185 * @consumed: number of bytes consumed by the caller so far
2186 * @data: destination pointer for data to be returned
2187 * @st: state variable
2189 * Reads a block of skb data at &consumed relative to the
2190 * lower offset specified to skb_prepare_seq_read(). Assigns
2191 * the head of the data block to &data and returns the length
2192 * of the block or 0 if the end of the skb data or the upper
2193 * offset has been reached.
2195 * The caller is not required to consume all of the data
2196 * returned, i.e. &consumed is typically set to the number
2197 * of bytes already consumed and the next call to
2198 * skb_seq_read() will return the remaining part of the block.
2200 * Note 1: The size of each block of data returned can be arbitary,
2201 * this limitation is the cost for zerocopy seqeuental
2202 * reads of potentially non linear data.
2204 * Note 2: Fragment lists within fragments are not implemented
2205 * at the moment, state->root_skb could be replaced with
2206 * a stack for this purpose.
2208 unsigned int skb_seq_read(unsigned int consumed, const u8 **data,
2209 struct skb_seq_state *st)
2211 unsigned int block_limit, abs_offset = consumed + st->lower_offset;
2214 if (unlikely(abs_offset >= st->upper_offset))
2218 block_limit = skb_headlen(st->cur_skb);
2220 if (abs_offset < block_limit) {
2221 *data = st->cur_skb->data + abs_offset;
2222 return block_limit - abs_offset;
2225 if (st->frag_idx == 0 && !st->frag_data)
2226 st->stepped_offset += skb_headlen(st->cur_skb);
2228 while (st->frag_idx < skb_shinfo(st->cur_skb)->nr_frags) {
2229 frag = &skb_shinfo(st->cur_skb)->frags[st->frag_idx];
2230 block_limit = frag->size + st->stepped_offset;
2232 if (abs_offset < block_limit) {
2234 st->frag_data = kmap_skb_frag(frag);
2236 *data = (u8 *) st->frag_data + frag->page_offset +
2237 (abs_offset - st->stepped_offset);
2239 return block_limit - abs_offset;
2242 if (st->frag_data) {
2243 kunmap_skb_frag(st->frag_data);
2244 st->frag_data = NULL;
2248 st->stepped_offset += frag->size;
2251 if (st->frag_data) {
2252 kunmap_skb_frag(st->frag_data);
2253 st->frag_data = NULL;
2256 if (st->cur_skb->next) {
2257 st->cur_skb = st->cur_skb->next;
2260 } else if (st->root_skb == st->cur_skb &&
2261 skb_shinfo(st->root_skb)->frag_list) {
2262 st->cur_skb = skb_shinfo(st->root_skb)->frag_list;
2270 * skb_abort_seq_read - Abort a sequential read of skb data
2271 * @st: state variable
2273 * Must be called if skb_seq_read() was not called until it
2276 void skb_abort_seq_read(struct skb_seq_state *st)
2279 kunmap_skb_frag(st->frag_data);
2282 #define TS_SKB_CB(state) ((struct skb_seq_state *) &((state)->cb))
2284 static unsigned int skb_ts_get_next_block(unsigned int offset, const u8 **text,
2285 struct ts_config *conf,
2286 struct ts_state *state)
2288 return skb_seq_read(offset, text, TS_SKB_CB(state));
2291 static void skb_ts_finish(struct ts_config *conf, struct ts_state *state)
2293 skb_abort_seq_read(TS_SKB_CB(state));
2297 * skb_find_text - Find a text pattern in skb data
2298 * @skb: the buffer to look in
2299 * @from: search offset
2301 * @config: textsearch configuration
2302 * @state: uninitialized textsearch state variable
2304 * Finds a pattern in the skb data according to the specified
2305 * textsearch configuration. Use textsearch_next() to retrieve
2306 * subsequent occurrences of the pattern. Returns the offset
2307 * to the first occurrence or UINT_MAX if no match was found.
2309 unsigned int skb_find_text(struct sk_buff *skb, unsigned int from,
2310 unsigned int to, struct ts_config *config,
2311 struct ts_state *state)
2315 config->get_next_block = skb_ts_get_next_block;
2316 config->finish = skb_ts_finish;
2318 skb_prepare_seq_read(skb, from, to, TS_SKB_CB(state));
2320 ret = textsearch_find(config, state);
2321 return (ret <= to - from ? ret : UINT_MAX);
2325 * skb_append_datato_frags: - append the user data to a skb
2326 * @sk: sock structure
2327 * @skb: skb structure to be appened with user data.
2328 * @getfrag: call back function to be used for getting the user data
2329 * @from: pointer to user message iov
2330 * @length: length of the iov message
2332 * Description: This procedure append the user data in the fragment part
2333 * of the skb if any page alloc fails user this procedure returns -ENOMEM
2335 int skb_append_datato_frags(struct sock *sk, struct sk_buff *skb,
2336 int (*getfrag)(void *from, char *to, int offset,
2337 int len, int odd, struct sk_buff *skb),
2338 void *from, int length)
2341 skb_frag_t *frag = NULL;
2342 struct page *page = NULL;
2348 /* Return error if we don't have space for new frag */
2349 frg_cnt = skb_shinfo(skb)->nr_frags;
2350 if (frg_cnt >= MAX_SKB_FRAGS)
2353 /* allocate a new page for next frag */
2354 page = alloc_pages(sk->sk_allocation, 0);
2356 /* If alloc_page fails just return failure and caller will
2357 * free previous allocated pages by doing kfree_skb()
2362 /* initialize the next frag */
2363 sk->sk_sndmsg_page = page;
2364 sk->sk_sndmsg_off = 0;
2365 skb_fill_page_desc(skb, frg_cnt, page, 0, 0);
2366 skb->truesize += PAGE_SIZE;
2367 atomic_add(PAGE_SIZE, &sk->sk_wmem_alloc);
2369 /* get the new initialized frag */
2370 frg_cnt = skb_shinfo(skb)->nr_frags;
2371 frag = &skb_shinfo(skb)->frags[frg_cnt - 1];
2373 /* copy the user data to page */
2374 left = PAGE_SIZE - frag->page_offset;
2375 copy = (length > left)? left : length;
2377 ret = getfrag(from, (page_address(frag->page) +
2378 frag->page_offset + frag->size),
2379 offset, copy, 0, skb);
2383 /* copy was successful so update the size parameters */
2384 sk->sk_sndmsg_off += copy;
2387 skb->data_len += copy;
2391 } while (length > 0);
2397 * skb_pull_rcsum - pull skb and update receive checksum
2398 * @skb: buffer to update
2399 * @len: length of data pulled
2401 * This function performs an skb_pull on the packet and updates
2402 * the CHECKSUM_COMPLETE checksum. It should be used on
2403 * receive path processing instead of skb_pull unless you know
2404 * that the checksum difference is zero (e.g., a valid IP header)
2405 * or you are setting ip_summed to CHECKSUM_NONE.
2407 unsigned char *skb_pull_rcsum(struct sk_buff *skb, unsigned int len)
2409 BUG_ON(len > skb->len);
2411 BUG_ON(skb->len < skb->data_len);
2412 skb_postpull_rcsum(skb, skb->data, len);
2413 return skb->data += len;
2416 EXPORT_SYMBOL_GPL(skb_pull_rcsum);
2419 * skb_segment - Perform protocol segmentation on skb.
2420 * @skb: buffer to segment
2421 * @features: features for the output path (see dev->features)
2423 * This function performs segmentation on the given skb. It returns
2424 * a pointer to the first in a list of new skbs for the segments.
2425 * In case of error it returns ERR_PTR(err).
2427 struct sk_buff *skb_segment(struct sk_buff *skb, int features)
2429 struct sk_buff *segs = NULL;
2430 struct sk_buff *tail = NULL;
2431 struct sk_buff *fskb = skb_shinfo(skb)->frag_list;
2432 unsigned int mss = skb_shinfo(skb)->gso_size;
2433 unsigned int doffset = skb->data - skb_mac_header(skb);
2434 unsigned int offset = doffset;
2435 unsigned int headroom;
2437 int sg = features & NETIF_F_SG;
2438 int nfrags = skb_shinfo(skb)->nr_frags;
2443 __skb_push(skb, doffset);
2444 headroom = skb_headroom(skb);
2445 pos = skb_headlen(skb);
2448 struct sk_buff *nskb;
2453 len = skb->len - offset;
2457 hsize = skb_headlen(skb) - offset;
2460 if (hsize > len || !sg)
2463 if (!hsize && i >= nfrags) {
2464 BUG_ON(fskb->len != len);
2467 nskb = skb_clone(fskb, GFP_ATOMIC);
2470 if (unlikely(!nskb))
2473 hsize = skb_end_pointer(nskb) - nskb->head;
2474 if (skb_cow_head(nskb, doffset + headroom)) {
2479 nskb->truesize += skb_end_pointer(nskb) - nskb->head -
2481 skb_release_head_state(nskb);
2482 __skb_push(nskb, doffset);
2484 nskb = alloc_skb(hsize + doffset + headroom,
2487 if (unlikely(!nskb))
2490 skb_reserve(nskb, headroom);
2491 __skb_put(nskb, doffset);
2500 __copy_skb_header(nskb, skb);
2501 nskb->mac_len = skb->mac_len;
2503 skb_reset_mac_header(nskb);
2504 skb_set_network_header(nskb, skb->mac_len);
2505 nskb->transport_header = (nskb->network_header +
2506 skb_network_header_len(skb));
2507 skb_copy_from_linear_data(skb, nskb->data, doffset);
2509 if (pos >= offset + len)
2513 nskb->ip_summed = CHECKSUM_NONE;
2514 nskb->csum = skb_copy_and_csum_bits(skb, offset,
2520 frag = skb_shinfo(nskb)->frags;
2522 skb_copy_from_linear_data_offset(skb, offset,
2523 skb_put(nskb, hsize), hsize);
2525 while (pos < offset + len && i < nfrags) {
2526 *frag = skb_shinfo(skb)->frags[i];
2527 get_page(frag->page);
2531 frag->page_offset += offset - pos;
2532 frag->size -= offset - pos;
2535 skb_shinfo(nskb)->nr_frags++;
2537 if (pos + size <= offset + len) {
2541 frag->size -= pos + size - (offset + len);
2548 if (pos < offset + len) {
2549 struct sk_buff *fskb2 = fskb;
2551 BUG_ON(pos + fskb->len != offset + len);
2557 fskb2 = skb_clone(fskb2, GFP_ATOMIC);
2563 BUG_ON(skb_shinfo(nskb)->frag_list);
2564 skb_shinfo(nskb)->frag_list = fskb2;
2568 nskb->data_len = len - hsize;
2569 nskb->len += nskb->data_len;
2570 nskb->truesize += nskb->data_len;
2571 } while ((offset += len) < skb->len);
2576 while ((skb = segs)) {
2580 return ERR_PTR(err);
2583 EXPORT_SYMBOL_GPL(skb_segment);
2585 int skb_gro_receive(struct sk_buff **head, struct sk_buff *skb)
2587 struct sk_buff *p = *head;
2588 struct sk_buff *nskb;
2589 unsigned int headroom;
2590 unsigned int hlen = p->data - skb_mac_header(p);
2592 if (hlen + p->len + skb->len >= 65536)
2595 if (skb_shinfo(p)->frag_list)
2597 else if (!skb_headlen(p) && !skb_headlen(skb) &&
2598 skb_shinfo(p)->nr_frags + skb_shinfo(skb)->nr_frags <
2600 memcpy(skb_shinfo(p)->frags + skb_shinfo(p)->nr_frags,
2601 skb_shinfo(skb)->frags,
2602 skb_shinfo(skb)->nr_frags * sizeof(skb_frag_t));
2604 skb_shinfo(p)->nr_frags += skb_shinfo(skb)->nr_frags;
2605 skb_shinfo(skb)->nr_frags = 0;
2607 skb->truesize -= skb->data_len;
2608 skb->len -= skb->data_len;
2611 NAPI_GRO_CB(skb)->free = 1;
2615 headroom = skb_headroom(p);
2616 nskb = netdev_alloc_skb(p->dev, headroom);
2617 if (unlikely(!nskb))
2620 __copy_skb_header(nskb, p);
2621 nskb->mac_len = p->mac_len;
2623 skb_reserve(nskb, headroom);
2625 skb_set_mac_header(nskb, -hlen);
2626 skb_set_network_header(nskb, skb_network_offset(p));
2627 skb_set_transport_header(nskb, skb_transport_offset(p));
2629 memcpy(skb_mac_header(nskb), skb_mac_header(p), hlen);
2631 *NAPI_GRO_CB(nskb) = *NAPI_GRO_CB(p);
2632 skb_shinfo(nskb)->frag_list = p;
2633 skb_shinfo(nskb)->gso_size = skb_shinfo(p)->gso_size;
2634 skb_header_release(p);
2637 nskb->data_len += p->len;
2638 nskb->truesize += p->len;
2639 nskb->len += p->len;
2642 nskb->next = p->next;
2648 p->prev->next = skb;
2650 skb_header_release(skb);
2653 NAPI_GRO_CB(p)->count++;
2654 p->data_len += skb->len;
2655 p->truesize += skb->len;
2658 NAPI_GRO_CB(skb)->same_flow = 1;
2661 EXPORT_SYMBOL_GPL(skb_gro_receive);
2663 void __init skb_init(void)
2665 skbuff_head_cache = kmem_cache_create("skbuff_head_cache",
2666 sizeof(struct sk_buff),
2668 SLAB_HWCACHE_ALIGN|SLAB_PANIC,
2670 skbuff_fclone_cache = kmem_cache_create("skbuff_fclone_cache",
2671 (2*sizeof(struct sk_buff)) +
2674 SLAB_HWCACHE_ALIGN|SLAB_PANIC,
2679 * skb_to_sgvec - Fill a scatter-gather list from a socket buffer
2680 * @skb: Socket buffer containing the buffers to be mapped
2681 * @sg: The scatter-gather list to map into
2682 * @offset: The offset into the buffer's contents to start mapping
2683 * @len: Length of buffer space to be mapped
2685 * Fill the specified scatter-gather list with mappings/pointers into a
2686 * region of the buffer space attached to a socket buffer.
2689 __skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int len)
2691 int start = skb_headlen(skb);
2692 int i, copy = start - offset;
2698 sg_set_buf(sg, skb->data + offset, copy);
2700 if ((len -= copy) == 0)
2705 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
2708 WARN_ON(start > offset + len);
2710 end = start + skb_shinfo(skb)->frags[i].size;
2711 if ((copy = end - offset) > 0) {
2712 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
2716 sg_set_page(&sg[elt], frag->page, copy,
2717 frag->page_offset+offset-start);
2726 if (skb_shinfo(skb)->frag_list) {
2727 struct sk_buff *list = skb_shinfo(skb)->frag_list;
2729 for (; list; list = list->next) {
2732 WARN_ON(start > offset + len);
2734 end = start + list->len;
2735 if ((copy = end - offset) > 0) {
2738 elt += __skb_to_sgvec(list, sg+elt, offset - start,
2740 if ((len -= copy) == 0)
2751 int skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int len)
2753 int nsg = __skb_to_sgvec(skb, sg, offset, len);
2755 sg_mark_end(&sg[nsg - 1]);
2761 * skb_cow_data - Check that a socket buffer's data buffers are writable
2762 * @skb: The socket buffer to check.
2763 * @tailbits: Amount of trailing space to be added
2764 * @trailer: Returned pointer to the skb where the @tailbits space begins
2766 * Make sure that the data buffers attached to a socket buffer are
2767 * writable. If they are not, private copies are made of the data buffers
2768 * and the socket buffer is set to use these instead.
2770 * If @tailbits is given, make sure that there is space to write @tailbits
2771 * bytes of data beyond current end of socket buffer. @trailer will be
2772 * set to point to the skb in which this space begins.
2774 * The number of scatterlist elements required to completely map the
2775 * COW'd and extended socket buffer will be returned.
2777 int skb_cow_data(struct sk_buff *skb, int tailbits, struct sk_buff **trailer)
2781 struct sk_buff *skb1, **skb_p;
2783 /* If skb is cloned or its head is paged, reallocate
2784 * head pulling out all the pages (pages are considered not writable
2785 * at the moment even if they are anonymous).
2787 if ((skb_cloned(skb) || skb_shinfo(skb)->nr_frags) &&
2788 __pskb_pull_tail(skb, skb_pagelen(skb)-skb_headlen(skb)) == NULL)
2791 /* Easy case. Most of packets will go this way. */
2792 if (!skb_shinfo(skb)->frag_list) {
2793 /* A little of trouble, not enough of space for trailer.
2794 * This should not happen, when stack is tuned to generate
2795 * good frames. OK, on miss we reallocate and reserve even more
2796 * space, 128 bytes is fair. */
2798 if (skb_tailroom(skb) < tailbits &&
2799 pskb_expand_head(skb, 0, tailbits-skb_tailroom(skb)+128, GFP_ATOMIC))
2807 /* Misery. We are in troubles, going to mincer fragments... */
2810 skb_p = &skb_shinfo(skb)->frag_list;
2813 while ((skb1 = *skb_p) != NULL) {
2816 /* The fragment is partially pulled by someone,
2817 * this can happen on input. Copy it and everything
2820 if (skb_shared(skb1))
2823 /* If the skb is the last, worry about trailer. */
2825 if (skb1->next == NULL && tailbits) {
2826 if (skb_shinfo(skb1)->nr_frags ||
2827 skb_shinfo(skb1)->frag_list ||
2828 skb_tailroom(skb1) < tailbits)
2829 ntail = tailbits + 128;
2835 skb_shinfo(skb1)->nr_frags ||
2836 skb_shinfo(skb1)->frag_list) {
2837 struct sk_buff *skb2;
2839 /* Fuck, we are miserable poor guys... */
2841 skb2 = skb_copy(skb1, GFP_ATOMIC);
2843 skb2 = skb_copy_expand(skb1,
2847 if (unlikely(skb2 == NULL))
2851 skb_set_owner_w(skb2, skb1->sk);
2853 /* Looking around. Are we still alive?
2854 * OK, link new skb, drop old one */
2856 skb2->next = skb1->next;
2863 skb_p = &skb1->next;
2870 * skb_partial_csum_set - set up and verify partial csum values for packet
2871 * @skb: the skb to set
2872 * @start: the number of bytes after skb->data to start checksumming.
2873 * @off: the offset from start to place the checksum.
2875 * For untrusted partially-checksummed packets, we need to make sure the values
2876 * for skb->csum_start and skb->csum_offset are valid so we don't oops.
2878 * This function checks and sets those values and skb->ip_summed: if this
2879 * returns false you should drop the packet.
2881 bool skb_partial_csum_set(struct sk_buff *skb, u16 start, u16 off)
2883 if (unlikely(start > skb->len - 2) ||
2884 unlikely((int)start + off > skb->len - 2)) {
2885 if (net_ratelimit())
2887 "bad partial csum: csum=%u/%u len=%u\n",
2888 start, off, skb->len);
2891 skb->ip_summed = CHECKSUM_PARTIAL;
2892 skb->csum_start = skb_headroom(skb) + start;
2893 skb->csum_offset = off;
2897 void __skb_warn_lro_forwarding(const struct sk_buff *skb)
2899 if (net_ratelimit())
2900 pr_warning("%s: received packets cannot be forwarded"
2901 " while LRO is enabled\n", skb->dev->name);
2904 EXPORT_SYMBOL(___pskb_trim);
2905 EXPORT_SYMBOL(__kfree_skb);
2906 EXPORT_SYMBOL(kfree_skb);
2907 EXPORT_SYMBOL(__pskb_pull_tail);
2908 EXPORT_SYMBOL(__alloc_skb);
2909 EXPORT_SYMBOL(__netdev_alloc_skb);
2910 EXPORT_SYMBOL(pskb_copy);
2911 EXPORT_SYMBOL(pskb_expand_head);
2912 EXPORT_SYMBOL(skb_checksum);
2913 EXPORT_SYMBOL(skb_clone);
2914 EXPORT_SYMBOL(skb_copy);
2915 EXPORT_SYMBOL(skb_copy_and_csum_bits);
2916 EXPORT_SYMBOL(skb_copy_and_csum_dev);
2917 EXPORT_SYMBOL(skb_copy_bits);
2918 EXPORT_SYMBOL(skb_copy_expand);
2919 EXPORT_SYMBOL(skb_over_panic);
2920 EXPORT_SYMBOL(skb_pad);
2921 EXPORT_SYMBOL(skb_realloc_headroom);
2922 EXPORT_SYMBOL(skb_under_panic);
2923 EXPORT_SYMBOL(skb_dequeue);
2924 EXPORT_SYMBOL(skb_dequeue_tail);
2925 EXPORT_SYMBOL(skb_insert);
2926 EXPORT_SYMBOL(skb_queue_purge);
2927 EXPORT_SYMBOL(skb_queue_head);
2928 EXPORT_SYMBOL(skb_queue_tail);
2929 EXPORT_SYMBOL(skb_unlink);
2930 EXPORT_SYMBOL(skb_append);
2931 EXPORT_SYMBOL(skb_split);
2932 EXPORT_SYMBOL(skb_prepare_seq_read);
2933 EXPORT_SYMBOL(skb_seq_read);
2934 EXPORT_SYMBOL(skb_abort_seq_read);
2935 EXPORT_SYMBOL(skb_find_text);
2936 EXPORT_SYMBOL(skb_append_datato_frags);
2937 EXPORT_SYMBOL(__skb_warn_lro_forwarding);
2939 EXPORT_SYMBOL_GPL(skb_to_sgvec);
2940 EXPORT_SYMBOL_GPL(skb_cow_data);
2941 EXPORT_SYMBOL_GPL(skb_partial_csum_set);