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>
58 #include <linux/scatterlist.h>
60 #include <net/protocol.h>
63 #include <net/checksum.h>
66 #include <asm/uaccess.h>
67 #include <asm/system.h>
71 static struct kmem_cache
*skbuff_head_cache __read_mostly
;
72 static struct kmem_cache
*skbuff_fclone_cache __read_mostly
;
75 * Keep out-of-line to prevent kernel bloat.
76 * __builtin_return_address is not used because it is not always
81 * skb_over_panic - private function
86 * Out of line support code for skb_put(). Not user callable.
88 void skb_over_panic(struct sk_buff
*skb
, int sz
, void *here
)
90 printk(KERN_EMERG
"skb_over_panic: text:%p len:%d put:%d head:%p "
91 "data:%p tail:%#lx end:%#lx dev:%s\n",
92 here
, skb
->len
, sz
, skb
->head
, skb
->data
,
93 (unsigned long)skb
->tail
, (unsigned long)skb
->end
,
94 skb
->dev
? skb
->dev
->name
: "<NULL>");
99 * skb_under_panic - private function
104 * Out of line support code for skb_push(). Not user callable.
107 void skb_under_panic(struct sk_buff
*skb
, int sz
, void *here
)
109 printk(KERN_EMERG
"skb_under_panic: text:%p len:%d put:%d head:%p "
110 "data:%p tail:%#lx end:%#lx dev:%s\n",
111 here
, skb
->len
, sz
, skb
->head
, skb
->data
,
112 (unsigned long)skb
->tail
, (unsigned long)skb
->end
,
113 skb
->dev
? skb
->dev
->name
: "<NULL>");
117 void skb_truesize_bug(struct sk_buff
*skb
)
119 printk(KERN_ERR
"SKB BUG: Invalid truesize (%u) "
120 "len=%u, sizeof(sk_buff)=%Zd\n",
121 skb
->truesize
, skb
->len
, sizeof(struct sk_buff
));
123 EXPORT_SYMBOL(skb_truesize_bug
);
125 /* Allocate a new skbuff. We do this ourselves so we can fill in a few
126 * 'private' fields and also do memory statistics to find all the
132 * __alloc_skb - allocate a network buffer
133 * @size: size to allocate
134 * @gfp_mask: allocation mask
135 * @fclone: allocate from fclone cache instead of head cache
136 * and allocate a cloned (child) skb
137 * @node: numa node to allocate memory on
139 * Allocate a new &sk_buff. The returned buffer has no headroom and a
140 * tail room of size bytes. The object has a reference count of one.
141 * The return is the buffer. On a failure the return is %NULL.
143 * Buffers may only be allocated from interrupts using a @gfp_mask of
146 struct sk_buff
*__alloc_skb(unsigned int size
, gfp_t gfp_mask
,
147 int fclone
, int node
)
149 struct kmem_cache
*cache
;
150 struct skb_shared_info
*shinfo
;
154 cache
= fclone
? skbuff_fclone_cache
: skbuff_head_cache
;
157 skb
= kmem_cache_alloc_node(cache
, gfp_mask
& ~__GFP_DMA
, node
);
161 size
= SKB_DATA_ALIGN(size
);
162 data
= kmalloc_node_track_caller(size
+ sizeof(struct skb_shared_info
),
168 * See comment in sk_buff definition, just before the 'tail' member
170 memset(skb
, 0, offsetof(struct sk_buff
, tail
));
171 skb
->truesize
= size
+ sizeof(struct sk_buff
);
172 atomic_set(&skb
->users
, 1);
175 skb_reset_tail_pointer(skb
);
176 skb
->end
= skb
->tail
+ size
;
177 /* make sure we initialize shinfo sequentially */
178 shinfo
= skb_shinfo(skb
);
179 atomic_set(&shinfo
->dataref
, 1);
180 shinfo
->nr_frags
= 0;
181 shinfo
->gso_size
= 0;
182 shinfo
->gso_segs
= 0;
183 shinfo
->gso_type
= 0;
184 shinfo
->ip6_frag_id
= 0;
185 shinfo
->frag_list
= NULL
;
188 struct sk_buff
*child
= skb
+ 1;
189 atomic_t
*fclone_ref
= (atomic_t
*) (child
+ 1);
191 skb
->fclone
= SKB_FCLONE_ORIG
;
192 atomic_set(fclone_ref
, 1);
194 child
->fclone
= SKB_FCLONE_UNAVAILABLE
;
199 kmem_cache_free(cache
, skb
);
205 * __netdev_alloc_skb - allocate an skbuff for rx on a specific device
206 * @dev: network device to receive on
207 * @length: length to allocate
208 * @gfp_mask: get_free_pages mask, passed to alloc_skb
210 * Allocate a new &sk_buff and assign it a usage count of one. The
211 * buffer has unspecified headroom built in. Users should allocate
212 * the headroom they think they need without accounting for the
213 * built in space. The built in space is used for optimisations.
215 * %NULL is returned if there is no free memory.
217 struct sk_buff
*__netdev_alloc_skb(struct net_device
*dev
,
218 unsigned int length
, gfp_t gfp_mask
)
220 int node
= dev
->dev
.parent
? dev_to_node(dev
->dev
.parent
) : -1;
223 skb
= __alloc_skb(length
+ NET_SKB_PAD
, gfp_mask
, 0, node
);
225 skb_reserve(skb
, NET_SKB_PAD
);
231 static void skb_drop_list(struct sk_buff
**listp
)
233 struct sk_buff
*list
= *listp
;
238 struct sk_buff
*this = list
;
244 static inline void skb_drop_fraglist(struct sk_buff
*skb
)
246 skb_drop_list(&skb_shinfo(skb
)->frag_list
);
249 static void skb_clone_fraglist(struct sk_buff
*skb
)
251 struct sk_buff
*list
;
253 for (list
= skb_shinfo(skb
)->frag_list
; list
; list
= list
->next
)
257 static void skb_release_data(struct sk_buff
*skb
)
260 !atomic_sub_return(skb
->nohdr
? (1 << SKB_DATAREF_SHIFT
) + 1 : 1,
261 &skb_shinfo(skb
)->dataref
)) {
262 if (skb_shinfo(skb
)->nr_frags
) {
264 for (i
= 0; i
< skb_shinfo(skb
)->nr_frags
; i
++)
265 put_page(skb_shinfo(skb
)->frags
[i
].page
);
268 if (skb_shinfo(skb
)->frag_list
)
269 skb_drop_fraglist(skb
);
276 * Free an skbuff by memory without cleaning the state.
278 static void kfree_skbmem(struct sk_buff
*skb
)
280 struct sk_buff
*other
;
281 atomic_t
*fclone_ref
;
283 switch (skb
->fclone
) {
284 case SKB_FCLONE_UNAVAILABLE
:
285 kmem_cache_free(skbuff_head_cache
, skb
);
288 case SKB_FCLONE_ORIG
:
289 fclone_ref
= (atomic_t
*) (skb
+ 2);
290 if (atomic_dec_and_test(fclone_ref
))
291 kmem_cache_free(skbuff_fclone_cache
, skb
);
294 case SKB_FCLONE_CLONE
:
295 fclone_ref
= (atomic_t
*) (skb
+ 1);
298 /* The clone portion is available for
299 * fast-cloning again.
301 skb
->fclone
= SKB_FCLONE_UNAVAILABLE
;
303 if (atomic_dec_and_test(fclone_ref
))
304 kmem_cache_free(skbuff_fclone_cache
, other
);
309 /* Free everything but the sk_buff shell. */
310 static void skb_release_all(struct sk_buff
*skb
)
312 dst_release(skb
->dst
);
314 secpath_put(skb
->sp
);
316 if (skb
->destructor
) {
318 skb
->destructor(skb
);
320 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
321 nf_conntrack_put(skb
->nfct
);
322 nf_conntrack_put_reasm(skb
->nfct_reasm
);
324 #ifdef CONFIG_BRIDGE_NETFILTER
325 nf_bridge_put(skb
->nf_bridge
);
327 /* XXX: IS this still necessary? - JHS */
328 #ifdef CONFIG_NET_SCHED
330 #ifdef CONFIG_NET_CLS_ACT
334 skb_release_data(skb
);
338 * __kfree_skb - private function
341 * Free an sk_buff. Release anything attached to the buffer.
342 * Clean the state. This is an internal helper function. Users should
343 * always call kfree_skb
346 void __kfree_skb(struct sk_buff
*skb
)
348 skb_release_all(skb
);
353 * kfree_skb - free an sk_buff
354 * @skb: buffer to free
356 * Drop a reference to the buffer and free it if the usage count has
359 void kfree_skb(struct sk_buff
*skb
)
363 if (likely(atomic_read(&skb
->users
) == 1))
365 else if (likely(!atomic_dec_and_test(&skb
->users
)))
370 static void __copy_skb_header(struct sk_buff
*new, const struct sk_buff
*old
)
372 new->tstamp
= old
->tstamp
;
374 new->transport_header
= old
->transport_header
;
375 new->network_header
= old
->network_header
;
376 new->mac_header
= old
->mac_header
;
377 new->dst
= dst_clone(old
->dst
);
379 new->sp
= secpath_get(old
->sp
);
381 memcpy(new->cb
, old
->cb
, sizeof(old
->cb
));
382 new->csum_start
= old
->csum_start
;
383 new->csum_offset
= old
->csum_offset
;
384 new->local_df
= old
->local_df
;
385 new->pkt_type
= old
->pkt_type
;
386 new->ip_summed
= old
->ip_summed
;
387 skb_copy_queue_mapping(new, old
);
388 new->priority
= old
->priority
;
389 #if defined(CONFIG_IP_VS) || defined(CONFIG_IP_VS_MODULE)
390 new->ipvs_property
= old
->ipvs_property
;
392 new->protocol
= old
->protocol
;
393 new->mark
= old
->mark
;
395 #if defined(CONFIG_NETFILTER_XT_TARGET_TRACE) || \
396 defined(CONFIG_NETFILTER_XT_TARGET_TRACE_MODULE)
397 new->nf_trace
= old
->nf_trace
;
399 #ifdef CONFIG_NET_SCHED
400 new->tc_index
= old
->tc_index
;
401 #ifdef CONFIG_NET_CLS_ACT
402 new->tc_verd
= old
->tc_verd
;
405 skb_copy_secmark(new, old
);
408 static struct sk_buff
*__skb_clone(struct sk_buff
*n
, struct sk_buff
*skb
)
410 #define C(x) n->x = skb->x
412 n
->next
= n
->prev
= NULL
;
414 __copy_skb_header(n
, skb
);
419 n
->hdr_len
= skb
->nohdr
? skb_headroom(skb
) : skb
->hdr_len
;
422 n
->destructor
= NULL
;
429 atomic_set(&n
->users
, 1);
431 atomic_inc(&(skb_shinfo(skb
)->dataref
));
439 * skb_morph - morph one skb into another
440 * @dst: the skb to receive the contents
441 * @src: the skb to supply the contents
443 * This is identical to skb_clone except that the target skb is
444 * supplied by the user.
446 * The target skb is returned upon exit.
448 struct sk_buff
*skb_morph(struct sk_buff
*dst
, struct sk_buff
*src
)
450 skb_release_all(dst
);
451 return __skb_clone(dst
, src
);
453 EXPORT_SYMBOL_GPL(skb_morph
);
456 * skb_clone - duplicate an sk_buff
457 * @skb: buffer to clone
458 * @gfp_mask: allocation priority
460 * Duplicate an &sk_buff. The new one is not owned by a socket. Both
461 * copies share the same packet data but not structure. The new
462 * buffer has a reference count of 1. If the allocation fails the
463 * function returns %NULL otherwise the new buffer is returned.
465 * If this function is called from an interrupt gfp_mask() must be
469 struct sk_buff
*skb_clone(struct sk_buff
*skb
, gfp_t gfp_mask
)
474 if (skb
->fclone
== SKB_FCLONE_ORIG
&&
475 n
->fclone
== SKB_FCLONE_UNAVAILABLE
) {
476 atomic_t
*fclone_ref
= (atomic_t
*) (n
+ 1);
477 n
->fclone
= SKB_FCLONE_CLONE
;
478 atomic_inc(fclone_ref
);
480 n
= kmem_cache_alloc(skbuff_head_cache
, gfp_mask
);
483 n
->fclone
= SKB_FCLONE_UNAVAILABLE
;
486 return __skb_clone(n
, skb
);
489 static void copy_skb_header(struct sk_buff
*new, const struct sk_buff
*old
)
491 #ifndef NET_SKBUFF_DATA_USES_OFFSET
493 * Shift between the two data areas in bytes
495 unsigned long offset
= new->data
- old
->data
;
498 __copy_skb_header(new, old
);
500 #ifndef NET_SKBUFF_DATA_USES_OFFSET
501 /* {transport,network,mac}_header are relative to skb->head */
502 new->transport_header
+= offset
;
503 new->network_header
+= offset
;
504 new->mac_header
+= offset
;
506 skb_shinfo(new)->gso_size
= skb_shinfo(old
)->gso_size
;
507 skb_shinfo(new)->gso_segs
= skb_shinfo(old
)->gso_segs
;
508 skb_shinfo(new)->gso_type
= skb_shinfo(old
)->gso_type
;
512 * skb_copy - create private copy of an sk_buff
513 * @skb: buffer to copy
514 * @gfp_mask: allocation priority
516 * Make a copy of both an &sk_buff and its data. This is used when the
517 * caller wishes to modify the data and needs a private copy of the
518 * data to alter. Returns %NULL on failure or the pointer to the buffer
519 * on success. The returned buffer has a reference count of 1.
521 * As by-product this function converts non-linear &sk_buff to linear
522 * one, so that &sk_buff becomes completely private and caller is allowed
523 * to modify all the data of returned buffer. This means that this
524 * function is not recommended for use in circumstances when only
525 * header is going to be modified. Use pskb_copy() instead.
528 struct sk_buff
*skb_copy(const struct sk_buff
*skb
, gfp_t gfp_mask
)
530 int headerlen
= skb
->data
- skb
->head
;
532 * Allocate the copy buffer
535 #ifdef NET_SKBUFF_DATA_USES_OFFSET
536 n
= alloc_skb(skb
->end
+ skb
->data_len
, gfp_mask
);
538 n
= alloc_skb(skb
->end
- skb
->head
+ skb
->data_len
, gfp_mask
);
543 /* Set the data pointer */
544 skb_reserve(n
, headerlen
);
545 /* Set the tail pointer and length */
546 skb_put(n
, skb
->len
);
548 if (skb_copy_bits(skb
, -headerlen
, n
->head
, headerlen
+ skb
->len
))
551 copy_skb_header(n
, skb
);
557 * pskb_copy - create copy of an sk_buff with private head.
558 * @skb: buffer to copy
559 * @gfp_mask: allocation priority
561 * Make a copy of both an &sk_buff and part of its data, located
562 * in header. Fragmented data remain shared. This is used when
563 * the caller wishes to modify only header of &sk_buff and needs
564 * private copy of the header to alter. Returns %NULL on failure
565 * or the pointer to the buffer on success.
566 * The returned buffer has a reference count of 1.
569 struct sk_buff
*pskb_copy(struct sk_buff
*skb
, gfp_t gfp_mask
)
572 * Allocate the copy buffer
575 #ifdef NET_SKBUFF_DATA_USES_OFFSET
576 n
= alloc_skb(skb
->end
, gfp_mask
);
578 n
= alloc_skb(skb
->end
- skb
->head
, gfp_mask
);
583 /* Set the data pointer */
584 skb_reserve(n
, skb
->data
- skb
->head
);
585 /* Set the tail pointer and length */
586 skb_put(n
, skb_headlen(skb
));
588 skb_copy_from_linear_data(skb
, n
->data
, n
->len
);
590 n
->truesize
+= skb
->data_len
;
591 n
->data_len
= skb
->data_len
;
594 if (skb_shinfo(skb
)->nr_frags
) {
597 for (i
= 0; i
< skb_shinfo(skb
)->nr_frags
; i
++) {
598 skb_shinfo(n
)->frags
[i
] = skb_shinfo(skb
)->frags
[i
];
599 get_page(skb_shinfo(n
)->frags
[i
].page
);
601 skb_shinfo(n
)->nr_frags
= i
;
604 if (skb_shinfo(skb
)->frag_list
) {
605 skb_shinfo(n
)->frag_list
= skb_shinfo(skb
)->frag_list
;
606 skb_clone_fraglist(n
);
609 copy_skb_header(n
, skb
);
615 * pskb_expand_head - reallocate header of &sk_buff
616 * @skb: buffer to reallocate
617 * @nhead: room to add at head
618 * @ntail: room to add at tail
619 * @gfp_mask: allocation priority
621 * Expands (or creates identical copy, if &nhead and &ntail are zero)
622 * header of skb. &sk_buff itself is not changed. &sk_buff MUST have
623 * reference count of 1. Returns zero in the case of success or error,
624 * if expansion failed. In the last case, &sk_buff is not changed.
626 * All the pointers pointing into skb header may change and must be
627 * reloaded after call to this function.
630 int pskb_expand_head(struct sk_buff
*skb
, int nhead
, int ntail
,
635 #ifdef NET_SKBUFF_DATA_USES_OFFSET
636 int size
= nhead
+ skb
->end
+ ntail
;
638 int size
= nhead
+ (skb
->end
- skb
->head
) + ntail
;
645 size
= SKB_DATA_ALIGN(size
);
647 data
= kmalloc(size
+ sizeof(struct skb_shared_info
), gfp_mask
);
651 /* Copy only real data... and, alas, header. This should be
652 * optimized for the cases when header is void. */
653 #ifdef NET_SKBUFF_DATA_USES_OFFSET
654 memcpy(data
+ nhead
, skb
->head
, skb
->tail
);
656 memcpy(data
+ nhead
, skb
->head
, skb
->tail
- skb
->head
);
658 memcpy(data
+ size
, skb_end_pointer(skb
),
659 sizeof(struct skb_shared_info
));
661 for (i
= 0; i
< skb_shinfo(skb
)->nr_frags
; i
++)
662 get_page(skb_shinfo(skb
)->frags
[i
].page
);
664 if (skb_shinfo(skb
)->frag_list
)
665 skb_clone_fraglist(skb
);
667 skb_release_data(skb
);
669 off
= (data
+ nhead
) - skb
->head
;
673 #ifdef NET_SKBUFF_DATA_USES_OFFSET
677 skb
->end
= skb
->head
+ size
;
679 /* {transport,network,mac}_header and tail are relative to skb->head */
681 skb
->transport_header
+= off
;
682 skb
->network_header
+= off
;
683 skb
->mac_header
+= off
;
684 skb
->csum_start
+= nhead
;
688 atomic_set(&skb_shinfo(skb
)->dataref
, 1);
695 /* Make private copy of skb with writable head and some headroom */
697 struct sk_buff
*skb_realloc_headroom(struct sk_buff
*skb
, unsigned int headroom
)
699 struct sk_buff
*skb2
;
700 int delta
= headroom
- skb_headroom(skb
);
703 skb2
= pskb_copy(skb
, GFP_ATOMIC
);
705 skb2
= skb_clone(skb
, GFP_ATOMIC
);
706 if (skb2
&& pskb_expand_head(skb2
, SKB_DATA_ALIGN(delta
), 0,
717 * skb_copy_expand - copy and expand sk_buff
718 * @skb: buffer to copy
719 * @newheadroom: new free bytes at head
720 * @newtailroom: new free bytes at tail
721 * @gfp_mask: allocation priority
723 * Make a copy of both an &sk_buff and its data and while doing so
724 * allocate additional space.
726 * This is used when the caller wishes to modify the data and needs a
727 * private copy of the data to alter as well as more space for new fields.
728 * Returns %NULL on failure or the pointer to the buffer
729 * on success. The returned buffer has a reference count of 1.
731 * You must pass %GFP_ATOMIC as the allocation priority if this function
732 * is called from an interrupt.
734 struct sk_buff
*skb_copy_expand(const struct sk_buff
*skb
,
735 int newheadroom
, int newtailroom
,
739 * Allocate the copy buffer
741 struct sk_buff
*n
= alloc_skb(newheadroom
+ skb
->len
+ newtailroom
,
743 int oldheadroom
= skb_headroom(skb
);
744 int head_copy_len
, head_copy_off
;
750 skb_reserve(n
, newheadroom
);
752 /* Set the tail pointer and length */
753 skb_put(n
, skb
->len
);
755 head_copy_len
= oldheadroom
;
757 if (newheadroom
<= head_copy_len
)
758 head_copy_len
= newheadroom
;
760 head_copy_off
= newheadroom
- head_copy_len
;
762 /* Copy the linear header and data. */
763 if (skb_copy_bits(skb
, -head_copy_len
, n
->head
+ head_copy_off
,
764 skb
->len
+ head_copy_len
))
767 copy_skb_header(n
, skb
);
769 off
= newheadroom
- oldheadroom
;
770 n
->csum_start
+= off
;
771 #ifdef NET_SKBUFF_DATA_USES_OFFSET
772 n
->transport_header
+= off
;
773 n
->network_header
+= off
;
774 n
->mac_header
+= off
;
781 * skb_pad - zero pad the tail of an skb
782 * @skb: buffer to pad
785 * Ensure that a buffer is followed by a padding area that is zero
786 * filled. Used by network drivers which may DMA or transfer data
787 * beyond the buffer end onto the wire.
789 * May return error in out of memory cases. The skb is freed on error.
792 int skb_pad(struct sk_buff
*skb
, int pad
)
797 /* If the skbuff is non linear tailroom is always zero.. */
798 if (!skb_cloned(skb
) && skb_tailroom(skb
) >= pad
) {
799 memset(skb
->data
+skb
->len
, 0, pad
);
803 ntail
= skb
->data_len
+ pad
- (skb
->end
- skb
->tail
);
804 if (likely(skb_cloned(skb
) || ntail
> 0)) {
805 err
= pskb_expand_head(skb
, 0, ntail
, GFP_ATOMIC
);
810 /* FIXME: The use of this function with non-linear skb's really needs
813 err
= skb_linearize(skb
);
817 memset(skb
->data
+ skb
->len
, 0, pad
);
825 /* Trims skb to length len. It can change skb pointers.
828 int ___pskb_trim(struct sk_buff
*skb
, unsigned int len
)
830 struct sk_buff
**fragp
;
831 struct sk_buff
*frag
;
832 int offset
= skb_headlen(skb
);
833 int nfrags
= skb_shinfo(skb
)->nr_frags
;
837 if (skb_cloned(skb
) &&
838 unlikely((err
= pskb_expand_head(skb
, 0, 0, GFP_ATOMIC
))))
845 for (; i
< nfrags
; i
++) {
846 int end
= offset
+ skb_shinfo(skb
)->frags
[i
].size
;
853 skb_shinfo(skb
)->frags
[i
++].size
= len
- offset
;
856 skb_shinfo(skb
)->nr_frags
= i
;
858 for (; i
< nfrags
; i
++)
859 put_page(skb_shinfo(skb
)->frags
[i
].page
);
861 if (skb_shinfo(skb
)->frag_list
)
862 skb_drop_fraglist(skb
);
866 for (fragp
= &skb_shinfo(skb
)->frag_list
; (frag
= *fragp
);
867 fragp
= &frag
->next
) {
868 int end
= offset
+ frag
->len
;
870 if (skb_shared(frag
)) {
871 struct sk_buff
*nfrag
;
873 nfrag
= skb_clone(frag
, GFP_ATOMIC
);
874 if (unlikely(!nfrag
))
877 nfrag
->next
= frag
->next
;
889 unlikely((err
= pskb_trim(frag
, len
- offset
))))
893 skb_drop_list(&frag
->next
);
898 if (len
> skb_headlen(skb
)) {
899 skb
->data_len
-= skb
->len
- len
;
904 skb_set_tail_pointer(skb
, len
);
911 * __pskb_pull_tail - advance tail of skb header
912 * @skb: buffer to reallocate
913 * @delta: number of bytes to advance tail
915 * The function makes a sense only on a fragmented &sk_buff,
916 * it expands header moving its tail forward and copying necessary
917 * data from fragmented part.
919 * &sk_buff MUST have reference count of 1.
921 * Returns %NULL (and &sk_buff does not change) if pull failed
922 * or value of new tail of skb in the case of success.
924 * All the pointers pointing into skb header may change and must be
925 * reloaded after call to this function.
928 /* Moves tail of skb head forward, copying data from fragmented part,
929 * when it is necessary.
930 * 1. It may fail due to malloc failure.
931 * 2. It may change skb pointers.
933 * It is pretty complicated. Luckily, it is called only in exceptional cases.
935 unsigned char *__pskb_pull_tail(struct sk_buff
*skb
, int delta
)
937 /* If skb has not enough free space at tail, get new one
938 * plus 128 bytes for future expansions. If we have enough
939 * room at tail, reallocate without expansion only if skb is cloned.
941 int i
, k
, eat
= (skb
->tail
+ delta
) - skb
->end
;
943 if (eat
> 0 || skb_cloned(skb
)) {
944 if (pskb_expand_head(skb
, 0, eat
> 0 ? eat
+ 128 : 0,
949 if (skb_copy_bits(skb
, skb_headlen(skb
), skb_tail_pointer(skb
), delta
))
952 /* Optimization: no fragments, no reasons to preestimate
953 * size of pulled pages. Superb.
955 if (!skb_shinfo(skb
)->frag_list
)
958 /* Estimate size of pulled pages. */
960 for (i
= 0; i
< skb_shinfo(skb
)->nr_frags
; i
++) {
961 if (skb_shinfo(skb
)->frags
[i
].size
>= eat
)
963 eat
-= skb_shinfo(skb
)->frags
[i
].size
;
966 /* If we need update frag list, we are in troubles.
967 * Certainly, it possible to add an offset to skb data,
968 * but taking into account that pulling is expected to
969 * be very rare operation, it is worth to fight against
970 * further bloating skb head and crucify ourselves here instead.
971 * Pure masohism, indeed. 8)8)
974 struct sk_buff
*list
= skb_shinfo(skb
)->frag_list
;
975 struct sk_buff
*clone
= NULL
;
976 struct sk_buff
*insp
= NULL
;
981 if (list
->len
<= eat
) {
982 /* Eaten as whole. */
987 /* Eaten partially. */
989 if (skb_shared(list
)) {
990 /* Sucks! We need to fork list. :-( */
991 clone
= skb_clone(list
, GFP_ATOMIC
);
997 /* This may be pulled without
1001 if (!pskb_pull(list
, eat
)) {
1010 /* Free pulled out fragments. */
1011 while ((list
= skb_shinfo(skb
)->frag_list
) != insp
) {
1012 skb_shinfo(skb
)->frag_list
= list
->next
;
1015 /* And insert new clone at head. */
1018 skb_shinfo(skb
)->frag_list
= clone
;
1021 /* Success! Now we may commit changes to skb data. */
1026 for (i
= 0; i
< skb_shinfo(skb
)->nr_frags
; i
++) {
1027 if (skb_shinfo(skb
)->frags
[i
].size
<= eat
) {
1028 put_page(skb_shinfo(skb
)->frags
[i
].page
);
1029 eat
-= skb_shinfo(skb
)->frags
[i
].size
;
1031 skb_shinfo(skb
)->frags
[k
] = skb_shinfo(skb
)->frags
[i
];
1033 skb_shinfo(skb
)->frags
[k
].page_offset
+= eat
;
1034 skb_shinfo(skb
)->frags
[k
].size
-= eat
;
1040 skb_shinfo(skb
)->nr_frags
= k
;
1043 skb
->data_len
-= delta
;
1045 return skb_tail_pointer(skb
);
1048 /* Copy some data bits from skb to kernel buffer. */
1050 int skb_copy_bits(const struct sk_buff
*skb
, int offset
, void *to
, int len
)
1053 int start
= skb_headlen(skb
);
1055 if (offset
> (int)skb
->len
- len
)
1059 if ((copy
= start
- offset
) > 0) {
1062 skb_copy_from_linear_data_offset(skb
, offset
, to
, copy
);
1063 if ((len
-= copy
) == 0)
1069 for (i
= 0; i
< skb_shinfo(skb
)->nr_frags
; i
++) {
1072 BUG_TRAP(start
<= offset
+ len
);
1074 end
= start
+ skb_shinfo(skb
)->frags
[i
].size
;
1075 if ((copy
= end
- offset
) > 0) {
1081 vaddr
= kmap_skb_frag(&skb_shinfo(skb
)->frags
[i
]);
1083 vaddr
+ skb_shinfo(skb
)->frags
[i
].page_offset
+
1084 offset
- start
, copy
);
1085 kunmap_skb_frag(vaddr
);
1087 if ((len
-= copy
) == 0)
1095 if (skb_shinfo(skb
)->frag_list
) {
1096 struct sk_buff
*list
= skb_shinfo(skb
)->frag_list
;
1098 for (; list
; list
= list
->next
) {
1101 BUG_TRAP(start
<= offset
+ len
);
1103 end
= start
+ list
->len
;
1104 if ((copy
= end
- offset
) > 0) {
1107 if (skb_copy_bits(list
, offset
- start
,
1110 if ((len
-= copy
) == 0)
1126 * skb_store_bits - store bits from kernel buffer to skb
1127 * @skb: destination buffer
1128 * @offset: offset in destination
1129 * @from: source buffer
1130 * @len: number of bytes to copy
1132 * Copy the specified number of bytes from the source buffer to the
1133 * destination skb. This function handles all the messy bits of
1134 * traversing fragment lists and such.
1137 int skb_store_bits(struct sk_buff
*skb
, int offset
, const void *from
, int len
)
1140 int start
= skb_headlen(skb
);
1142 if (offset
> (int)skb
->len
- len
)
1145 if ((copy
= start
- offset
) > 0) {
1148 skb_copy_to_linear_data_offset(skb
, offset
, from
, copy
);
1149 if ((len
-= copy
) == 0)
1155 for (i
= 0; i
< skb_shinfo(skb
)->nr_frags
; i
++) {
1156 skb_frag_t
*frag
= &skb_shinfo(skb
)->frags
[i
];
1159 BUG_TRAP(start
<= offset
+ len
);
1161 end
= start
+ frag
->size
;
1162 if ((copy
= end
- offset
) > 0) {
1168 vaddr
= kmap_skb_frag(frag
);
1169 memcpy(vaddr
+ frag
->page_offset
+ offset
- start
,
1171 kunmap_skb_frag(vaddr
);
1173 if ((len
-= copy
) == 0)
1181 if (skb_shinfo(skb
)->frag_list
) {
1182 struct sk_buff
*list
= skb_shinfo(skb
)->frag_list
;
1184 for (; list
; list
= list
->next
) {
1187 BUG_TRAP(start
<= offset
+ len
);
1189 end
= start
+ list
->len
;
1190 if ((copy
= end
- offset
) > 0) {
1193 if (skb_store_bits(list
, offset
- start
,
1196 if ((len
-= copy
) == 0)
1211 EXPORT_SYMBOL(skb_store_bits
);
1213 /* Checksum skb data. */
1215 __wsum
skb_checksum(const struct sk_buff
*skb
, int offset
,
1216 int len
, __wsum csum
)
1218 int start
= skb_headlen(skb
);
1219 int i
, copy
= start
- offset
;
1222 /* Checksum header. */
1226 csum
= csum_partial(skb
->data
+ offset
, copy
, csum
);
1227 if ((len
-= copy
) == 0)
1233 for (i
= 0; i
< skb_shinfo(skb
)->nr_frags
; i
++) {
1236 BUG_TRAP(start
<= offset
+ len
);
1238 end
= start
+ skb_shinfo(skb
)->frags
[i
].size
;
1239 if ((copy
= end
- offset
) > 0) {
1242 skb_frag_t
*frag
= &skb_shinfo(skb
)->frags
[i
];
1246 vaddr
= kmap_skb_frag(frag
);
1247 csum2
= csum_partial(vaddr
+ frag
->page_offset
+
1248 offset
- start
, copy
, 0);
1249 kunmap_skb_frag(vaddr
);
1250 csum
= csum_block_add(csum
, csum2
, pos
);
1259 if (skb_shinfo(skb
)->frag_list
) {
1260 struct sk_buff
*list
= skb_shinfo(skb
)->frag_list
;
1262 for (; list
; list
= list
->next
) {
1265 BUG_TRAP(start
<= offset
+ len
);
1267 end
= start
+ list
->len
;
1268 if ((copy
= end
- offset
) > 0) {
1272 csum2
= skb_checksum(list
, offset
- start
,
1274 csum
= csum_block_add(csum
, csum2
, pos
);
1275 if ((len
-= copy
) == 0)
1288 /* Both of above in one bottle. */
1290 __wsum
skb_copy_and_csum_bits(const struct sk_buff
*skb
, int offset
,
1291 u8
*to
, int len
, __wsum csum
)
1293 int start
= skb_headlen(skb
);
1294 int i
, copy
= start
- offset
;
1301 csum
= csum_partial_copy_nocheck(skb
->data
+ offset
, to
,
1303 if ((len
-= copy
) == 0)
1310 for (i
= 0; i
< skb_shinfo(skb
)->nr_frags
; i
++) {
1313 BUG_TRAP(start
<= offset
+ len
);
1315 end
= start
+ skb_shinfo(skb
)->frags
[i
].size
;
1316 if ((copy
= end
- offset
) > 0) {
1319 skb_frag_t
*frag
= &skb_shinfo(skb
)->frags
[i
];
1323 vaddr
= kmap_skb_frag(frag
);
1324 csum2
= csum_partial_copy_nocheck(vaddr
+
1328 kunmap_skb_frag(vaddr
);
1329 csum
= csum_block_add(csum
, csum2
, pos
);
1339 if (skb_shinfo(skb
)->frag_list
) {
1340 struct sk_buff
*list
= skb_shinfo(skb
)->frag_list
;
1342 for (; list
; list
= list
->next
) {
1346 BUG_TRAP(start
<= offset
+ len
);
1348 end
= start
+ list
->len
;
1349 if ((copy
= end
- offset
) > 0) {
1352 csum2
= skb_copy_and_csum_bits(list
,
1355 csum
= csum_block_add(csum
, csum2
, pos
);
1356 if ((len
-= copy
) == 0)
1369 void skb_copy_and_csum_dev(const struct sk_buff
*skb
, u8
*to
)
1374 if (skb
->ip_summed
== CHECKSUM_PARTIAL
)
1375 csstart
= skb
->csum_start
- skb_headroom(skb
);
1377 csstart
= skb_headlen(skb
);
1379 BUG_ON(csstart
> skb_headlen(skb
));
1381 skb_copy_from_linear_data(skb
, to
, csstart
);
1384 if (csstart
!= skb
->len
)
1385 csum
= skb_copy_and_csum_bits(skb
, csstart
, to
+ csstart
,
1386 skb
->len
- csstart
, 0);
1388 if (skb
->ip_summed
== CHECKSUM_PARTIAL
) {
1389 long csstuff
= csstart
+ skb
->csum_offset
;
1391 *((__sum16
*)(to
+ csstuff
)) = csum_fold(csum
);
1396 * skb_dequeue - remove from the head of the queue
1397 * @list: list to dequeue from
1399 * Remove the head of the list. The list lock is taken so the function
1400 * may be used safely with other locking list functions. The head item is
1401 * returned or %NULL if the list is empty.
1404 struct sk_buff
*skb_dequeue(struct sk_buff_head
*list
)
1406 unsigned long flags
;
1407 struct sk_buff
*result
;
1409 spin_lock_irqsave(&list
->lock
, flags
);
1410 result
= __skb_dequeue(list
);
1411 spin_unlock_irqrestore(&list
->lock
, flags
);
1416 * skb_dequeue_tail - remove from the tail of the queue
1417 * @list: list to dequeue from
1419 * Remove the tail of the list. The list lock is taken so the function
1420 * may be used safely with other locking list functions. The tail item is
1421 * returned or %NULL if the list is empty.
1423 struct sk_buff
*skb_dequeue_tail(struct sk_buff_head
*list
)
1425 unsigned long flags
;
1426 struct sk_buff
*result
;
1428 spin_lock_irqsave(&list
->lock
, flags
);
1429 result
= __skb_dequeue_tail(list
);
1430 spin_unlock_irqrestore(&list
->lock
, flags
);
1435 * skb_queue_purge - empty a list
1436 * @list: list to empty
1438 * Delete all buffers on an &sk_buff list. Each buffer is removed from
1439 * the list and one reference dropped. This function takes the list
1440 * lock and is atomic with respect to other list locking functions.
1442 void skb_queue_purge(struct sk_buff_head
*list
)
1444 struct sk_buff
*skb
;
1445 while ((skb
= skb_dequeue(list
)) != NULL
)
1450 * skb_queue_head - queue a buffer at the list head
1451 * @list: list to use
1452 * @newsk: buffer to queue
1454 * Queue a buffer at the start of the list. This function takes the
1455 * list lock and can be used safely with other locking &sk_buff functions
1458 * A buffer cannot be placed on two lists at the same time.
1460 void skb_queue_head(struct sk_buff_head
*list
, struct sk_buff
*newsk
)
1462 unsigned long flags
;
1464 spin_lock_irqsave(&list
->lock
, flags
);
1465 __skb_queue_head(list
, newsk
);
1466 spin_unlock_irqrestore(&list
->lock
, flags
);
1470 * skb_queue_tail - queue a buffer at the list tail
1471 * @list: list to use
1472 * @newsk: buffer to queue
1474 * Queue a buffer at the tail of the list. This function takes the
1475 * list lock and can be used safely with other locking &sk_buff functions
1478 * A buffer cannot be placed on two lists at the same time.
1480 void skb_queue_tail(struct sk_buff_head
*list
, struct sk_buff
*newsk
)
1482 unsigned long flags
;
1484 spin_lock_irqsave(&list
->lock
, flags
);
1485 __skb_queue_tail(list
, newsk
);
1486 spin_unlock_irqrestore(&list
->lock
, flags
);
1490 * skb_unlink - remove a buffer from a list
1491 * @skb: buffer to remove
1492 * @list: list to use
1494 * Remove a packet from a list. The list locks are taken and this
1495 * function is atomic with respect to other list locked calls
1497 * You must know what list the SKB is on.
1499 void skb_unlink(struct sk_buff
*skb
, struct sk_buff_head
*list
)
1501 unsigned long flags
;
1503 spin_lock_irqsave(&list
->lock
, flags
);
1504 __skb_unlink(skb
, list
);
1505 spin_unlock_irqrestore(&list
->lock
, flags
);
1509 * skb_append - append a buffer
1510 * @old: buffer to insert after
1511 * @newsk: buffer to insert
1512 * @list: list to use
1514 * Place a packet after a given packet in a list. The list locks are taken
1515 * and this function is atomic with respect to other list locked calls.
1516 * A buffer cannot be placed on two lists at the same time.
1518 void skb_append(struct sk_buff
*old
, struct sk_buff
*newsk
, struct sk_buff_head
*list
)
1520 unsigned long flags
;
1522 spin_lock_irqsave(&list
->lock
, flags
);
1523 __skb_append(old
, newsk
, list
);
1524 spin_unlock_irqrestore(&list
->lock
, flags
);
1529 * skb_insert - insert a buffer
1530 * @old: buffer to insert before
1531 * @newsk: buffer to insert
1532 * @list: list to use
1534 * Place a packet before a given packet in a list. The list locks are
1535 * taken and this function is atomic with respect to other list locked
1538 * A buffer cannot be placed on two lists at the same time.
1540 void skb_insert(struct sk_buff
*old
, struct sk_buff
*newsk
, struct sk_buff_head
*list
)
1542 unsigned long flags
;
1544 spin_lock_irqsave(&list
->lock
, flags
);
1545 __skb_insert(newsk
, old
->prev
, old
, list
);
1546 spin_unlock_irqrestore(&list
->lock
, flags
);
1549 static inline void skb_split_inside_header(struct sk_buff
*skb
,
1550 struct sk_buff
* skb1
,
1551 const u32 len
, const int pos
)
1555 skb_copy_from_linear_data_offset(skb
, len
, skb_put(skb1
, pos
- len
),
1557 /* And move data appendix as is. */
1558 for (i
= 0; i
< skb_shinfo(skb
)->nr_frags
; i
++)
1559 skb_shinfo(skb1
)->frags
[i
] = skb_shinfo(skb
)->frags
[i
];
1561 skb_shinfo(skb1
)->nr_frags
= skb_shinfo(skb
)->nr_frags
;
1562 skb_shinfo(skb
)->nr_frags
= 0;
1563 skb1
->data_len
= skb
->data_len
;
1564 skb1
->len
+= skb1
->data_len
;
1567 skb_set_tail_pointer(skb
, len
);
1570 static inline void skb_split_no_header(struct sk_buff
*skb
,
1571 struct sk_buff
* skb1
,
1572 const u32 len
, int pos
)
1575 const int nfrags
= skb_shinfo(skb
)->nr_frags
;
1577 skb_shinfo(skb
)->nr_frags
= 0;
1578 skb1
->len
= skb1
->data_len
= skb
->len
- len
;
1580 skb
->data_len
= len
- pos
;
1582 for (i
= 0; i
< nfrags
; i
++) {
1583 int size
= skb_shinfo(skb
)->frags
[i
].size
;
1585 if (pos
+ size
> len
) {
1586 skb_shinfo(skb1
)->frags
[k
] = skb_shinfo(skb
)->frags
[i
];
1590 * We have two variants in this case:
1591 * 1. Move all the frag to the second
1592 * part, if it is possible. F.e.
1593 * this approach is mandatory for TUX,
1594 * where splitting is expensive.
1595 * 2. Split is accurately. We make this.
1597 get_page(skb_shinfo(skb
)->frags
[i
].page
);
1598 skb_shinfo(skb1
)->frags
[0].page_offset
+= len
- pos
;
1599 skb_shinfo(skb1
)->frags
[0].size
-= len
- pos
;
1600 skb_shinfo(skb
)->frags
[i
].size
= len
- pos
;
1601 skb_shinfo(skb
)->nr_frags
++;
1605 skb_shinfo(skb
)->nr_frags
++;
1608 skb_shinfo(skb1
)->nr_frags
= k
;
1612 * skb_split - Split fragmented skb to two parts at length len.
1613 * @skb: the buffer to split
1614 * @skb1: the buffer to receive the second part
1615 * @len: new length for skb
1617 void skb_split(struct sk_buff
*skb
, struct sk_buff
*skb1
, const u32 len
)
1619 int pos
= skb_headlen(skb
);
1621 if (len
< pos
) /* Split line is inside header. */
1622 skb_split_inside_header(skb
, skb1
, len
, pos
);
1623 else /* Second chunk has no header, nothing to copy. */
1624 skb_split_no_header(skb
, skb1
, len
, pos
);
1628 * skb_prepare_seq_read - Prepare a sequential read of skb data
1629 * @skb: the buffer to read
1630 * @from: lower offset of data to be read
1631 * @to: upper offset of data to be read
1632 * @st: state variable
1634 * Initializes the specified state variable. Must be called before
1635 * invoking skb_seq_read() for the first time.
1637 void skb_prepare_seq_read(struct sk_buff
*skb
, unsigned int from
,
1638 unsigned int to
, struct skb_seq_state
*st
)
1640 st
->lower_offset
= from
;
1641 st
->upper_offset
= to
;
1642 st
->root_skb
= st
->cur_skb
= skb
;
1643 st
->frag_idx
= st
->stepped_offset
= 0;
1644 st
->frag_data
= NULL
;
1648 * skb_seq_read - Sequentially read skb data
1649 * @consumed: number of bytes consumed by the caller so far
1650 * @data: destination pointer for data to be returned
1651 * @st: state variable
1653 * Reads a block of skb data at &consumed relative to the
1654 * lower offset specified to skb_prepare_seq_read(). Assigns
1655 * the head of the data block to &data and returns the length
1656 * of the block or 0 if the end of the skb data or the upper
1657 * offset has been reached.
1659 * The caller is not required to consume all of the data
1660 * returned, i.e. &consumed is typically set to the number
1661 * of bytes already consumed and the next call to
1662 * skb_seq_read() will return the remaining part of the block.
1664 * Note: The size of each block of data returned can be arbitary,
1665 * this limitation is the cost for zerocopy seqeuental
1666 * reads of potentially non linear data.
1668 * Note: Fragment lists within fragments are not implemented
1669 * at the moment, state->root_skb could be replaced with
1670 * a stack for this purpose.
1672 unsigned int skb_seq_read(unsigned int consumed
, const u8
**data
,
1673 struct skb_seq_state
*st
)
1675 unsigned int block_limit
, abs_offset
= consumed
+ st
->lower_offset
;
1678 if (unlikely(abs_offset
>= st
->upper_offset
))
1682 block_limit
= skb_headlen(st
->cur_skb
);
1684 if (abs_offset
< block_limit
) {
1685 *data
= st
->cur_skb
->data
+ abs_offset
;
1686 return block_limit
- abs_offset
;
1689 if (st
->frag_idx
== 0 && !st
->frag_data
)
1690 st
->stepped_offset
+= skb_headlen(st
->cur_skb
);
1692 while (st
->frag_idx
< skb_shinfo(st
->cur_skb
)->nr_frags
) {
1693 frag
= &skb_shinfo(st
->cur_skb
)->frags
[st
->frag_idx
];
1694 block_limit
= frag
->size
+ st
->stepped_offset
;
1696 if (abs_offset
< block_limit
) {
1698 st
->frag_data
= kmap_skb_frag(frag
);
1700 *data
= (u8
*) st
->frag_data
+ frag
->page_offset
+
1701 (abs_offset
- st
->stepped_offset
);
1703 return block_limit
- abs_offset
;
1706 if (st
->frag_data
) {
1707 kunmap_skb_frag(st
->frag_data
);
1708 st
->frag_data
= NULL
;
1712 st
->stepped_offset
+= frag
->size
;
1715 if (st
->frag_data
) {
1716 kunmap_skb_frag(st
->frag_data
);
1717 st
->frag_data
= NULL
;
1720 if (st
->cur_skb
->next
) {
1721 st
->cur_skb
= st
->cur_skb
->next
;
1724 } else if (st
->root_skb
== st
->cur_skb
&&
1725 skb_shinfo(st
->root_skb
)->frag_list
) {
1726 st
->cur_skb
= skb_shinfo(st
->root_skb
)->frag_list
;
1734 * skb_abort_seq_read - Abort a sequential read of skb data
1735 * @st: state variable
1737 * Must be called if skb_seq_read() was not called until it
1740 void skb_abort_seq_read(struct skb_seq_state
*st
)
1743 kunmap_skb_frag(st
->frag_data
);
1746 #define TS_SKB_CB(state) ((struct skb_seq_state *) &((state)->cb))
1748 static unsigned int skb_ts_get_next_block(unsigned int offset
, const u8
**text
,
1749 struct ts_config
*conf
,
1750 struct ts_state
*state
)
1752 return skb_seq_read(offset
, text
, TS_SKB_CB(state
));
1755 static void skb_ts_finish(struct ts_config
*conf
, struct ts_state
*state
)
1757 skb_abort_seq_read(TS_SKB_CB(state
));
1761 * skb_find_text - Find a text pattern in skb data
1762 * @skb: the buffer to look in
1763 * @from: search offset
1765 * @config: textsearch configuration
1766 * @state: uninitialized textsearch state variable
1768 * Finds a pattern in the skb data according to the specified
1769 * textsearch configuration. Use textsearch_next() to retrieve
1770 * subsequent occurrences of the pattern. Returns the offset
1771 * to the first occurrence or UINT_MAX if no match was found.
1773 unsigned int skb_find_text(struct sk_buff
*skb
, unsigned int from
,
1774 unsigned int to
, struct ts_config
*config
,
1775 struct ts_state
*state
)
1779 config
->get_next_block
= skb_ts_get_next_block
;
1780 config
->finish
= skb_ts_finish
;
1782 skb_prepare_seq_read(skb
, from
, to
, TS_SKB_CB(state
));
1784 ret
= textsearch_find(config
, state
);
1785 return (ret
<= to
- from
? ret
: UINT_MAX
);
1789 * skb_append_datato_frags: - append the user data to a skb
1790 * @sk: sock structure
1791 * @skb: skb structure to be appened with user data.
1792 * @getfrag: call back function to be used for getting the user data
1793 * @from: pointer to user message iov
1794 * @length: length of the iov message
1796 * Description: This procedure append the user data in the fragment part
1797 * of the skb if any page alloc fails user this procedure returns -ENOMEM
1799 int skb_append_datato_frags(struct sock
*sk
, struct sk_buff
*skb
,
1800 int (*getfrag
)(void *from
, char *to
, int offset
,
1801 int len
, int odd
, struct sk_buff
*skb
),
1802 void *from
, int length
)
1805 skb_frag_t
*frag
= NULL
;
1806 struct page
*page
= NULL
;
1812 /* Return error if we don't have space for new frag */
1813 frg_cnt
= skb_shinfo(skb
)->nr_frags
;
1814 if (frg_cnt
>= MAX_SKB_FRAGS
)
1817 /* allocate a new page for next frag */
1818 page
= alloc_pages(sk
->sk_allocation
, 0);
1820 /* If alloc_page fails just return failure and caller will
1821 * free previous allocated pages by doing kfree_skb()
1826 /* initialize the next frag */
1827 sk
->sk_sndmsg_page
= page
;
1828 sk
->sk_sndmsg_off
= 0;
1829 skb_fill_page_desc(skb
, frg_cnt
, page
, 0, 0);
1830 skb
->truesize
+= PAGE_SIZE
;
1831 atomic_add(PAGE_SIZE
, &sk
->sk_wmem_alloc
);
1833 /* get the new initialized frag */
1834 frg_cnt
= skb_shinfo(skb
)->nr_frags
;
1835 frag
= &skb_shinfo(skb
)->frags
[frg_cnt
- 1];
1837 /* copy the user data to page */
1838 left
= PAGE_SIZE
- frag
->page_offset
;
1839 copy
= (length
> left
)? left
: length
;
1841 ret
= getfrag(from
, (page_address(frag
->page
) +
1842 frag
->page_offset
+ frag
->size
),
1843 offset
, copy
, 0, skb
);
1847 /* copy was successful so update the size parameters */
1848 sk
->sk_sndmsg_off
+= copy
;
1851 skb
->data_len
+= copy
;
1855 } while (length
> 0);
1861 * skb_pull_rcsum - pull skb and update receive checksum
1862 * @skb: buffer to update
1863 * @start: start of data before pull
1864 * @len: length of data pulled
1866 * This function performs an skb_pull on the packet and updates
1867 * update the CHECKSUM_COMPLETE checksum. It should be used on
1868 * receive path processing instead of skb_pull unless you know
1869 * that the checksum difference is zero (e.g., a valid IP header)
1870 * or you are setting ip_summed to CHECKSUM_NONE.
1872 unsigned char *skb_pull_rcsum(struct sk_buff
*skb
, unsigned int len
)
1874 BUG_ON(len
> skb
->len
);
1876 BUG_ON(skb
->len
< skb
->data_len
);
1877 skb_postpull_rcsum(skb
, skb
->data
, len
);
1878 return skb
->data
+= len
;
1881 EXPORT_SYMBOL_GPL(skb_pull_rcsum
);
1884 * skb_segment - Perform protocol segmentation on skb.
1885 * @skb: buffer to segment
1886 * @features: features for the output path (see dev->features)
1888 * This function performs segmentation on the given skb. It returns
1889 * the segment at the given position. It returns NULL if there are
1890 * no more segments to generate, or when an error is encountered.
1892 struct sk_buff
*skb_segment(struct sk_buff
*skb
, int features
)
1894 struct sk_buff
*segs
= NULL
;
1895 struct sk_buff
*tail
= NULL
;
1896 unsigned int mss
= skb_shinfo(skb
)->gso_size
;
1897 unsigned int doffset
= skb
->data
- skb_mac_header(skb
);
1898 unsigned int offset
= doffset
;
1899 unsigned int headroom
;
1901 int sg
= features
& NETIF_F_SG
;
1902 int nfrags
= skb_shinfo(skb
)->nr_frags
;
1907 __skb_push(skb
, doffset
);
1908 headroom
= skb_headroom(skb
);
1909 pos
= skb_headlen(skb
);
1912 struct sk_buff
*nskb
;
1918 len
= skb
->len
- offset
;
1922 hsize
= skb_headlen(skb
) - offset
;
1925 if (hsize
> len
|| !sg
)
1928 nskb
= alloc_skb(hsize
+ doffset
+ headroom
, GFP_ATOMIC
);
1929 if (unlikely(!nskb
))
1938 nskb
->dev
= skb
->dev
;
1939 skb_copy_queue_mapping(nskb
, skb
);
1940 nskb
->priority
= skb
->priority
;
1941 nskb
->protocol
= skb
->protocol
;
1942 nskb
->dst
= dst_clone(skb
->dst
);
1943 memcpy(nskb
->cb
, skb
->cb
, sizeof(skb
->cb
));
1944 nskb
->pkt_type
= skb
->pkt_type
;
1945 nskb
->mac_len
= skb
->mac_len
;
1947 skb_reserve(nskb
, headroom
);
1948 skb_reset_mac_header(nskb
);
1949 skb_set_network_header(nskb
, skb
->mac_len
);
1950 nskb
->transport_header
= (nskb
->network_header
+
1951 skb_network_header_len(skb
));
1952 skb_copy_from_linear_data(skb
, skb_put(nskb
, doffset
),
1955 nskb
->csum
= skb_copy_and_csum_bits(skb
, offset
,
1961 frag
= skb_shinfo(nskb
)->frags
;
1964 nskb
->ip_summed
= CHECKSUM_PARTIAL
;
1965 nskb
->csum
= skb
->csum
;
1966 skb_copy_from_linear_data_offset(skb
, offset
,
1967 skb_put(nskb
, hsize
), hsize
);
1969 while (pos
< offset
+ len
) {
1970 BUG_ON(i
>= nfrags
);
1972 *frag
= skb_shinfo(skb
)->frags
[i
];
1973 get_page(frag
->page
);
1977 frag
->page_offset
+= offset
- pos
;
1978 frag
->size
-= offset
- pos
;
1983 if (pos
+ size
<= offset
+ len
) {
1987 frag
->size
-= pos
+ size
- (offset
+ len
);
1994 skb_shinfo(nskb
)->nr_frags
= k
;
1995 nskb
->data_len
= len
- hsize
;
1996 nskb
->len
+= nskb
->data_len
;
1997 nskb
->truesize
+= nskb
->data_len
;
1998 } while ((offset
+= len
) < skb
->len
);
2003 while ((skb
= segs
)) {
2007 return ERR_PTR(err
);
2010 EXPORT_SYMBOL_GPL(skb_segment
);
2012 void __init
skb_init(void)
2014 skbuff_head_cache
= kmem_cache_create("skbuff_head_cache",
2015 sizeof(struct sk_buff
),
2017 SLAB_HWCACHE_ALIGN
|SLAB_PANIC
,
2019 skbuff_fclone_cache
= kmem_cache_create("skbuff_fclone_cache",
2020 (2*sizeof(struct sk_buff
)) +
2023 SLAB_HWCACHE_ALIGN
|SLAB_PANIC
,
2028 * skb_to_sgvec - Fill a scatter-gather list from a socket buffer
2029 * @skb: Socket buffer containing the buffers to be mapped
2030 * @sg: The scatter-gather list to map into
2031 * @offset: The offset into the buffer's contents to start mapping
2032 * @len: Length of buffer space to be mapped
2034 * Fill the specified scatter-gather list with mappings/pointers into a
2035 * region of the buffer space attached to a socket buffer.
2038 __skb_to_sgvec(struct sk_buff
*skb
, struct scatterlist
*sg
, int offset
, int len
)
2040 int start
= skb_headlen(skb
);
2041 int i
, copy
= start
- offset
;
2047 sg_set_buf(sg
, skb
->data
+ offset
, copy
);
2049 if ((len
-= copy
) == 0)
2054 for (i
= 0; i
< skb_shinfo(skb
)->nr_frags
; i
++) {
2057 BUG_TRAP(start
<= offset
+ len
);
2059 end
= start
+ skb_shinfo(skb
)->frags
[i
].size
;
2060 if ((copy
= end
- offset
) > 0) {
2061 skb_frag_t
*frag
= &skb_shinfo(skb
)->frags
[i
];
2065 sg_set_page(&sg
[elt
], frag
->page
, copy
,
2066 frag
->page_offset
+offset
-start
);
2075 if (skb_shinfo(skb
)->frag_list
) {
2076 struct sk_buff
*list
= skb_shinfo(skb
)->frag_list
;
2078 for (; list
; list
= list
->next
) {
2081 BUG_TRAP(start
<= offset
+ len
);
2083 end
= start
+ list
->len
;
2084 if ((copy
= end
- offset
) > 0) {
2087 elt
+= __skb_to_sgvec(list
, sg
+elt
, offset
- start
,
2089 if ((len
-= copy
) == 0)
2100 int skb_to_sgvec(struct sk_buff
*skb
, struct scatterlist
*sg
, int offset
, int len
)
2102 int nsg
= __skb_to_sgvec(skb
, sg
, offset
, len
);
2104 sg_mark_end(&sg
[nsg
- 1]);
2110 * skb_cow_data - Check that a socket buffer's data buffers are writable
2111 * @skb: The socket buffer to check.
2112 * @tailbits: Amount of trailing space to be added
2113 * @trailer: Returned pointer to the skb where the @tailbits space begins
2115 * Make sure that the data buffers attached to a socket buffer are
2116 * writable. If they are not, private copies are made of the data buffers
2117 * and the socket buffer is set to use these instead.
2119 * If @tailbits is given, make sure that there is space to write @tailbits
2120 * bytes of data beyond current end of socket buffer. @trailer will be
2121 * set to point to the skb in which this space begins.
2123 * The number of scatterlist elements required to completely map the
2124 * COW'd and extended socket buffer will be returned.
2126 int skb_cow_data(struct sk_buff
*skb
, int tailbits
, struct sk_buff
**trailer
)
2130 struct sk_buff
*skb1
, **skb_p
;
2132 /* If skb is cloned or its head is paged, reallocate
2133 * head pulling out all the pages (pages are considered not writable
2134 * at the moment even if they are anonymous).
2136 if ((skb_cloned(skb
) || skb_shinfo(skb
)->nr_frags
) &&
2137 __pskb_pull_tail(skb
, skb_pagelen(skb
)-skb_headlen(skb
)) == NULL
)
2140 /* Easy case. Most of packets will go this way. */
2141 if (!skb_shinfo(skb
)->frag_list
) {
2142 /* A little of trouble, not enough of space for trailer.
2143 * This should not happen, when stack is tuned to generate
2144 * good frames. OK, on miss we reallocate and reserve even more
2145 * space, 128 bytes is fair. */
2147 if (skb_tailroom(skb
) < tailbits
&&
2148 pskb_expand_head(skb
, 0, tailbits
-skb_tailroom(skb
)+128, GFP_ATOMIC
))
2156 /* Misery. We are in troubles, going to mincer fragments... */
2159 skb_p
= &skb_shinfo(skb
)->frag_list
;
2162 while ((skb1
= *skb_p
) != NULL
) {
2165 /* The fragment is partially pulled by someone,
2166 * this can happen on input. Copy it and everything
2169 if (skb_shared(skb1
))
2172 /* If the skb is the last, worry about trailer. */
2174 if (skb1
->next
== NULL
&& tailbits
) {
2175 if (skb_shinfo(skb1
)->nr_frags
||
2176 skb_shinfo(skb1
)->frag_list
||
2177 skb_tailroom(skb1
) < tailbits
)
2178 ntail
= tailbits
+ 128;
2184 skb_shinfo(skb1
)->nr_frags
||
2185 skb_shinfo(skb1
)->frag_list
) {
2186 struct sk_buff
*skb2
;
2188 /* Fuck, we are miserable poor guys... */
2190 skb2
= skb_copy(skb1
, GFP_ATOMIC
);
2192 skb2
= skb_copy_expand(skb1
,
2196 if (unlikely(skb2
== NULL
))
2200 skb_set_owner_w(skb2
, skb1
->sk
);
2202 /* Looking around. Are we still alive?
2203 * OK, link new skb, drop old one */
2205 skb2
->next
= skb1
->next
;
2212 skb_p
= &skb1
->next
;
2218 EXPORT_SYMBOL(___pskb_trim
);
2219 EXPORT_SYMBOL(__kfree_skb
);
2220 EXPORT_SYMBOL(kfree_skb
);
2221 EXPORT_SYMBOL(__pskb_pull_tail
);
2222 EXPORT_SYMBOL(__alloc_skb
);
2223 EXPORT_SYMBOL(__netdev_alloc_skb
);
2224 EXPORT_SYMBOL(pskb_copy
);
2225 EXPORT_SYMBOL(pskb_expand_head
);
2226 EXPORT_SYMBOL(skb_checksum
);
2227 EXPORT_SYMBOL(skb_clone
);
2228 EXPORT_SYMBOL(skb_copy
);
2229 EXPORT_SYMBOL(skb_copy_and_csum_bits
);
2230 EXPORT_SYMBOL(skb_copy_and_csum_dev
);
2231 EXPORT_SYMBOL(skb_copy_bits
);
2232 EXPORT_SYMBOL(skb_copy_expand
);
2233 EXPORT_SYMBOL(skb_over_panic
);
2234 EXPORT_SYMBOL(skb_pad
);
2235 EXPORT_SYMBOL(skb_realloc_headroom
);
2236 EXPORT_SYMBOL(skb_under_panic
);
2237 EXPORT_SYMBOL(skb_dequeue
);
2238 EXPORT_SYMBOL(skb_dequeue_tail
);
2239 EXPORT_SYMBOL(skb_insert
);
2240 EXPORT_SYMBOL(skb_queue_purge
);
2241 EXPORT_SYMBOL(skb_queue_head
);
2242 EXPORT_SYMBOL(skb_queue_tail
);
2243 EXPORT_SYMBOL(skb_unlink
);
2244 EXPORT_SYMBOL(skb_append
);
2245 EXPORT_SYMBOL(skb_split
);
2246 EXPORT_SYMBOL(skb_prepare_seq_read
);
2247 EXPORT_SYMBOL(skb_seq_read
);
2248 EXPORT_SYMBOL(skb_abort_seq_read
);
2249 EXPORT_SYMBOL(skb_find_text
);
2250 EXPORT_SYMBOL(skb_append_datato_frags
);
2252 EXPORT_SYMBOL_GPL(skb_to_sgvec
);
2253 EXPORT_SYMBOL_GPL(skb_cow_data
);