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>
58 #include <linux/errqueue.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
;
74 static void sock_pipe_buf_release(struct pipe_inode_info
*pipe
,
75 struct pipe_buffer
*buf
)
80 static void sock_pipe_buf_get(struct pipe_inode_info
*pipe
,
81 struct pipe_buffer
*buf
)
86 static int sock_pipe_buf_steal(struct pipe_inode_info
*pipe
,
87 struct pipe_buffer
*buf
)
93 /* Pipe buffer operations for a socket. */
94 static struct pipe_buf_operations sock_pipe_buf_ops
= {
96 .map
= generic_pipe_buf_map
,
97 .unmap
= generic_pipe_buf_unmap
,
98 .confirm
= generic_pipe_buf_confirm
,
99 .release
= sock_pipe_buf_release
,
100 .steal
= sock_pipe_buf_steal
,
101 .get
= sock_pipe_buf_get
,
105 * Keep out-of-line to prevent kernel bloat.
106 * __builtin_return_address is not used because it is not always
111 * skb_over_panic - private function
116 * Out of line support code for skb_put(). Not user callable.
118 void skb_over_panic(struct sk_buff
*skb
, int sz
, void *here
)
120 printk(KERN_EMERG
"skb_over_panic: text:%p len:%d put:%d head:%p "
121 "data:%p tail:%#lx end:%#lx dev:%s\n",
122 here
, skb
->len
, sz
, skb
->head
, skb
->data
,
123 (unsigned long)skb
->tail
, (unsigned long)skb
->end
,
124 skb
->dev
? skb
->dev
->name
: "<NULL>");
127 EXPORT_SYMBOL(skb_over_panic
);
130 * skb_under_panic - private function
135 * Out of line support code for skb_push(). Not user callable.
138 void skb_under_panic(struct sk_buff
*skb
, int sz
, void *here
)
140 printk(KERN_EMERG
"skb_under_panic: text:%p len:%d put:%d head:%p "
141 "data:%p tail:%#lx end:%#lx dev:%s\n",
142 here
, skb
->len
, sz
, skb
->head
, skb
->data
,
143 (unsigned long)skb
->tail
, (unsigned long)skb
->end
,
144 skb
->dev
? skb
->dev
->name
: "<NULL>");
147 EXPORT_SYMBOL(skb_under_panic
);
149 void skb_truesize_bug(struct sk_buff
*skb
)
151 WARN(net_ratelimit(), KERN_ERR
"SKB BUG: Invalid truesize (%u) "
152 "len=%u, sizeof(sk_buff)=%Zd\n",
153 skb
->truesize
, skb
->len
, sizeof(struct sk_buff
));
155 EXPORT_SYMBOL(skb_truesize_bug
);
157 /* Allocate a new skbuff. We do this ourselves so we can fill in a few
158 * 'private' fields and also do memory statistics to find all the
164 * __alloc_skb - allocate a network buffer
165 * @size: size to allocate
166 * @gfp_mask: allocation mask
167 * @fclone: allocate from fclone cache instead of head cache
168 * and allocate a cloned (child) skb
169 * @node: numa node to allocate memory on
171 * Allocate a new &sk_buff. The returned buffer has no headroom and a
172 * tail room of size bytes. The object has a reference count of one.
173 * The return is the buffer. On a failure the return is %NULL.
175 * Buffers may only be allocated from interrupts using a @gfp_mask of
178 struct sk_buff
*__alloc_skb(unsigned int size
, gfp_t gfp_mask
,
179 int fclone
, int node
)
181 struct kmem_cache
*cache
;
182 struct skb_shared_info
*shinfo
;
186 cache
= fclone
? skbuff_fclone_cache
: skbuff_head_cache
;
189 skb
= kmem_cache_alloc_node(cache
, gfp_mask
& ~__GFP_DMA
, node
);
193 size
= SKB_DATA_ALIGN(size
);
194 data
= kmalloc_node_track_caller(size
+ sizeof(struct skb_shared_info
),
200 * Only clear those fields we need to clear, not those that we will
201 * actually initialise below. Hence, don't put any more fields after
202 * the tail pointer in struct sk_buff!
204 memset(skb
, 0, offsetof(struct sk_buff
, tail
));
205 skb
->truesize
= size
+ sizeof(struct sk_buff
);
206 atomic_set(&skb
->users
, 1);
209 skb_reset_tail_pointer(skb
);
210 skb
->end
= skb
->tail
+ size
;
211 /* make sure we initialize shinfo sequentially */
212 shinfo
= skb_shinfo(skb
);
213 atomic_set(&shinfo
->dataref
, 1);
214 shinfo
->nr_frags
= 0;
215 shinfo
->gso_size
= 0;
216 shinfo
->gso_segs
= 0;
217 shinfo
->gso_type
= 0;
218 shinfo
->ip6_frag_id
= 0;
219 shinfo
->tx_flags
.flags
= 0;
220 shinfo
->frag_list
= NULL
;
221 memset(&shinfo
->hwtstamps
, 0, sizeof(shinfo
->hwtstamps
));
224 struct sk_buff
*child
= skb
+ 1;
225 atomic_t
*fclone_ref
= (atomic_t
*) (child
+ 1);
227 skb
->fclone
= SKB_FCLONE_ORIG
;
228 atomic_set(fclone_ref
, 1);
230 child
->fclone
= SKB_FCLONE_UNAVAILABLE
;
235 kmem_cache_free(cache
, skb
);
239 EXPORT_SYMBOL(__alloc_skb
);
242 * __netdev_alloc_skb - allocate an skbuff for rx on a specific device
243 * @dev: network device to receive on
244 * @length: length to allocate
245 * @gfp_mask: get_free_pages mask, passed to alloc_skb
247 * Allocate a new &sk_buff and assign it a usage count of one. The
248 * buffer has unspecified headroom built in. Users should allocate
249 * the headroom they think they need without accounting for the
250 * built in space. The built in space is used for optimisations.
252 * %NULL is returned if there is no free memory.
254 struct sk_buff
*__netdev_alloc_skb(struct net_device
*dev
,
255 unsigned int length
, gfp_t gfp_mask
)
257 int node
= dev
->dev
.parent
? dev_to_node(dev
->dev
.parent
) : -1;
260 skb
= __alloc_skb(length
+ NET_SKB_PAD
, gfp_mask
, 0, node
);
262 skb_reserve(skb
, NET_SKB_PAD
);
267 EXPORT_SYMBOL(__netdev_alloc_skb
);
269 struct page
*__netdev_alloc_page(struct net_device
*dev
, gfp_t gfp_mask
)
271 int node
= dev
->dev
.parent
? dev_to_node(dev
->dev
.parent
) : -1;
274 page
= alloc_pages_node(node
, gfp_mask
, 0);
277 EXPORT_SYMBOL(__netdev_alloc_page
);
279 void skb_add_rx_frag(struct sk_buff
*skb
, int i
, struct page
*page
, int off
,
282 skb_fill_page_desc(skb
, i
, page
, off
, size
);
284 skb
->data_len
+= size
;
285 skb
->truesize
+= size
;
287 EXPORT_SYMBOL(skb_add_rx_frag
);
290 * dev_alloc_skb - allocate an skbuff for receiving
291 * @length: length to allocate
293 * Allocate a new &sk_buff and assign it a usage count of one. The
294 * buffer has unspecified headroom built in. Users should allocate
295 * the headroom they think they need without accounting for the
296 * built in space. The built in space is used for optimisations.
298 * %NULL is returned if there is no free memory. Although this function
299 * allocates memory it can be called from an interrupt.
301 struct sk_buff
*dev_alloc_skb(unsigned int length
)
304 * There is more code here than it seems:
305 * __dev_alloc_skb is an inline
307 return __dev_alloc_skb(length
, GFP_ATOMIC
);
309 EXPORT_SYMBOL(dev_alloc_skb
);
311 static void skb_drop_list(struct sk_buff
**listp
)
313 struct sk_buff
*list
= *listp
;
318 struct sk_buff
*this = list
;
324 static inline void skb_drop_fraglist(struct sk_buff
*skb
)
326 skb_drop_list(&skb_shinfo(skb
)->frag_list
);
329 static void skb_clone_fraglist(struct sk_buff
*skb
)
331 struct sk_buff
*list
;
333 for (list
= skb_shinfo(skb
)->frag_list
; list
; list
= list
->next
)
337 static void skb_release_data(struct sk_buff
*skb
)
340 !atomic_sub_return(skb
->nohdr
? (1 << SKB_DATAREF_SHIFT
) + 1 : 1,
341 &skb_shinfo(skb
)->dataref
)) {
342 if (skb_shinfo(skb
)->nr_frags
) {
344 for (i
= 0; i
< skb_shinfo(skb
)->nr_frags
; i
++)
345 put_page(skb_shinfo(skb
)->frags
[i
].page
);
348 if (skb_shinfo(skb
)->frag_list
)
349 skb_drop_fraglist(skb
);
356 * Free an skbuff by memory without cleaning the state.
358 static void kfree_skbmem(struct sk_buff
*skb
)
360 struct sk_buff
*other
;
361 atomic_t
*fclone_ref
;
363 switch (skb
->fclone
) {
364 case SKB_FCLONE_UNAVAILABLE
:
365 kmem_cache_free(skbuff_head_cache
, skb
);
368 case SKB_FCLONE_ORIG
:
369 fclone_ref
= (atomic_t
*) (skb
+ 2);
370 if (atomic_dec_and_test(fclone_ref
))
371 kmem_cache_free(skbuff_fclone_cache
, skb
);
374 case SKB_FCLONE_CLONE
:
375 fclone_ref
= (atomic_t
*) (skb
+ 1);
378 /* The clone portion is available for
379 * fast-cloning again.
381 skb
->fclone
= SKB_FCLONE_UNAVAILABLE
;
383 if (atomic_dec_and_test(fclone_ref
))
384 kmem_cache_free(skbuff_fclone_cache
, other
);
389 static void skb_release_head_state(struct sk_buff
*skb
)
391 dst_release(skb
->dst
);
393 secpath_put(skb
->sp
);
395 if (skb
->destructor
) {
397 skb
->destructor(skb
);
399 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
400 nf_conntrack_put(skb
->nfct
);
401 nf_conntrack_put_reasm(skb
->nfct_reasm
);
403 #ifdef CONFIG_BRIDGE_NETFILTER
404 nf_bridge_put(skb
->nf_bridge
);
406 /* XXX: IS this still necessary? - JHS */
407 #ifdef CONFIG_NET_SCHED
409 #ifdef CONFIG_NET_CLS_ACT
415 /* Free everything but the sk_buff shell. */
416 static void skb_release_all(struct sk_buff
*skb
)
418 skb_release_head_state(skb
);
419 skb_release_data(skb
);
423 * __kfree_skb - private function
426 * Free an sk_buff. Release anything attached to the buffer.
427 * Clean the state. This is an internal helper function. Users should
428 * always call kfree_skb
431 void __kfree_skb(struct sk_buff
*skb
)
433 skb_release_all(skb
);
436 EXPORT_SYMBOL(__kfree_skb
);
439 * kfree_skb - free an sk_buff
440 * @skb: buffer to free
442 * Drop a reference to the buffer and free it if the usage count has
445 void kfree_skb(struct sk_buff
*skb
)
449 if (likely(atomic_read(&skb
->users
) == 1))
451 else if (likely(!atomic_dec_and_test(&skb
->users
)))
455 EXPORT_SYMBOL(kfree_skb
);
458 * skb_recycle_check - check if skb can be reused for receive
460 * @skb_size: minimum receive buffer size
462 * Checks that the skb passed in is not shared or cloned, and
463 * that it is linear and its head portion at least as large as
464 * skb_size so that it can be recycled as a receive buffer.
465 * If these conditions are met, this function does any necessary
466 * reference count dropping and cleans up the skbuff as if it
467 * just came from __alloc_skb().
469 int skb_recycle_check(struct sk_buff
*skb
, int skb_size
)
471 struct skb_shared_info
*shinfo
;
473 if (skb_is_nonlinear(skb
) || skb
->fclone
!= SKB_FCLONE_UNAVAILABLE
)
476 skb_size
= SKB_DATA_ALIGN(skb_size
+ NET_SKB_PAD
);
477 if (skb_end_pointer(skb
) - skb
->head
< skb_size
)
480 if (skb_shared(skb
) || skb_cloned(skb
))
483 skb_release_head_state(skb
);
484 shinfo
= skb_shinfo(skb
);
485 atomic_set(&shinfo
->dataref
, 1);
486 shinfo
->nr_frags
= 0;
487 shinfo
->gso_size
= 0;
488 shinfo
->gso_segs
= 0;
489 shinfo
->gso_type
= 0;
490 shinfo
->ip6_frag_id
= 0;
491 shinfo
->frag_list
= NULL
;
493 memset(skb
, 0, offsetof(struct sk_buff
, tail
));
494 skb
->data
= skb
->head
+ NET_SKB_PAD
;
495 skb_reset_tail_pointer(skb
);
499 EXPORT_SYMBOL(skb_recycle_check
);
501 static void __copy_skb_header(struct sk_buff
*new, const struct sk_buff
*old
)
503 new->tstamp
= old
->tstamp
;
505 new->transport_header
= old
->transport_header
;
506 new->network_header
= old
->network_header
;
507 new->mac_header
= old
->mac_header
;
508 new->dst
= dst_clone(old
->dst
);
510 new->sp
= secpath_get(old
->sp
);
512 memcpy(new->cb
, old
->cb
, sizeof(old
->cb
));
513 new->csum_start
= old
->csum_start
;
514 new->csum_offset
= old
->csum_offset
;
515 new->local_df
= old
->local_df
;
516 new->pkt_type
= old
->pkt_type
;
517 new->ip_summed
= old
->ip_summed
;
518 skb_copy_queue_mapping(new, old
);
519 new->priority
= old
->priority
;
520 #if defined(CONFIG_IP_VS) || defined(CONFIG_IP_VS_MODULE)
521 new->ipvs_property
= old
->ipvs_property
;
523 new->protocol
= old
->protocol
;
524 new->mark
= old
->mark
;
526 #if defined(CONFIG_NETFILTER_XT_TARGET_TRACE) || \
527 defined(CONFIG_NETFILTER_XT_TARGET_TRACE_MODULE)
528 new->nf_trace
= old
->nf_trace
;
530 #ifdef CONFIG_NET_SCHED
531 new->tc_index
= old
->tc_index
;
532 #ifdef CONFIG_NET_CLS_ACT
533 new->tc_verd
= old
->tc_verd
;
536 new->vlan_tci
= old
->vlan_tci
;
538 skb_copy_secmark(new, old
);
541 static struct sk_buff
*__skb_clone(struct sk_buff
*n
, struct sk_buff
*skb
)
543 #define C(x) n->x = skb->x
545 n
->next
= n
->prev
= NULL
;
547 __copy_skb_header(n
, skb
);
552 n
->hdr_len
= skb
->nohdr
? skb_headroom(skb
) : skb
->hdr_len
;
555 n
->destructor
= NULL
;
562 #if defined(CONFIG_MAC80211) || defined(CONFIG_MAC80211_MODULE)
566 atomic_set(&n
->users
, 1);
568 atomic_inc(&(skb_shinfo(skb
)->dataref
));
576 * skb_morph - morph one skb into another
577 * @dst: the skb to receive the contents
578 * @src: the skb to supply the contents
580 * This is identical to skb_clone except that the target skb is
581 * supplied by the user.
583 * The target skb is returned upon exit.
585 struct sk_buff
*skb_morph(struct sk_buff
*dst
, struct sk_buff
*src
)
587 skb_release_all(dst
);
588 return __skb_clone(dst
, src
);
590 EXPORT_SYMBOL_GPL(skb_morph
);
593 * skb_clone - duplicate an sk_buff
594 * @skb: buffer to clone
595 * @gfp_mask: allocation priority
597 * Duplicate an &sk_buff. The new one is not owned by a socket. Both
598 * copies share the same packet data but not structure. The new
599 * buffer has a reference count of 1. If the allocation fails the
600 * function returns %NULL otherwise the new buffer is returned.
602 * If this function is called from an interrupt gfp_mask() must be
606 struct sk_buff
*skb_clone(struct sk_buff
*skb
, gfp_t gfp_mask
)
611 if (skb
->fclone
== SKB_FCLONE_ORIG
&&
612 n
->fclone
== SKB_FCLONE_UNAVAILABLE
) {
613 atomic_t
*fclone_ref
= (atomic_t
*) (n
+ 1);
614 n
->fclone
= SKB_FCLONE_CLONE
;
615 atomic_inc(fclone_ref
);
617 n
= kmem_cache_alloc(skbuff_head_cache
, gfp_mask
);
620 n
->fclone
= SKB_FCLONE_UNAVAILABLE
;
623 return __skb_clone(n
, skb
);
625 EXPORT_SYMBOL(skb_clone
);
627 static void copy_skb_header(struct sk_buff
*new, const struct sk_buff
*old
)
629 #ifndef NET_SKBUFF_DATA_USES_OFFSET
631 * Shift between the two data areas in bytes
633 unsigned long offset
= new->data
- old
->data
;
636 __copy_skb_header(new, old
);
638 #ifndef NET_SKBUFF_DATA_USES_OFFSET
639 /* {transport,network,mac}_header are relative to skb->head */
640 new->transport_header
+= offset
;
641 new->network_header
+= offset
;
642 new->mac_header
+= offset
;
644 skb_shinfo(new)->gso_size
= skb_shinfo(old
)->gso_size
;
645 skb_shinfo(new)->gso_segs
= skb_shinfo(old
)->gso_segs
;
646 skb_shinfo(new)->gso_type
= skb_shinfo(old
)->gso_type
;
650 * skb_copy - create private copy of an sk_buff
651 * @skb: buffer to copy
652 * @gfp_mask: allocation priority
654 * Make a copy of both an &sk_buff and its data. This is used when the
655 * caller wishes to modify the data and needs a private copy of the
656 * data to alter. Returns %NULL on failure or the pointer to the buffer
657 * on success. The returned buffer has a reference count of 1.
659 * As by-product this function converts non-linear &sk_buff to linear
660 * one, so that &sk_buff becomes completely private and caller is allowed
661 * to modify all the data of returned buffer. This means that this
662 * function is not recommended for use in circumstances when only
663 * header is going to be modified. Use pskb_copy() instead.
666 struct sk_buff
*skb_copy(const struct sk_buff
*skb
, gfp_t gfp_mask
)
668 int headerlen
= skb
->data
- skb
->head
;
670 * Allocate the copy buffer
673 #ifdef NET_SKBUFF_DATA_USES_OFFSET
674 n
= alloc_skb(skb
->end
+ skb
->data_len
, gfp_mask
);
676 n
= alloc_skb(skb
->end
- skb
->head
+ skb
->data_len
, gfp_mask
);
681 /* Set the data pointer */
682 skb_reserve(n
, headerlen
);
683 /* Set the tail pointer and length */
684 skb_put(n
, skb
->len
);
686 if (skb_copy_bits(skb
, -headerlen
, n
->head
, headerlen
+ skb
->len
))
689 copy_skb_header(n
, skb
);
692 EXPORT_SYMBOL(skb_copy
);
695 * pskb_copy - create copy of an sk_buff with private head.
696 * @skb: buffer to copy
697 * @gfp_mask: allocation priority
699 * Make a copy of both an &sk_buff and part of its data, located
700 * in header. Fragmented data remain shared. This is used when
701 * the caller wishes to modify only header of &sk_buff and needs
702 * private copy of the header to alter. Returns %NULL on failure
703 * or the pointer to the buffer on success.
704 * The returned buffer has a reference count of 1.
707 struct sk_buff
*pskb_copy(struct sk_buff
*skb
, gfp_t gfp_mask
)
710 * Allocate the copy buffer
713 #ifdef NET_SKBUFF_DATA_USES_OFFSET
714 n
= alloc_skb(skb
->end
, gfp_mask
);
716 n
= alloc_skb(skb
->end
- skb
->head
, gfp_mask
);
721 /* Set the data pointer */
722 skb_reserve(n
, skb
->data
- skb
->head
);
723 /* Set the tail pointer and length */
724 skb_put(n
, skb_headlen(skb
));
726 skb_copy_from_linear_data(skb
, n
->data
, n
->len
);
728 n
->truesize
+= skb
->data_len
;
729 n
->data_len
= skb
->data_len
;
732 if (skb_shinfo(skb
)->nr_frags
) {
735 for (i
= 0; i
< skb_shinfo(skb
)->nr_frags
; i
++) {
736 skb_shinfo(n
)->frags
[i
] = skb_shinfo(skb
)->frags
[i
];
737 get_page(skb_shinfo(n
)->frags
[i
].page
);
739 skb_shinfo(n
)->nr_frags
= i
;
742 if (skb_shinfo(skb
)->frag_list
) {
743 skb_shinfo(n
)->frag_list
= skb_shinfo(skb
)->frag_list
;
744 skb_clone_fraglist(n
);
747 copy_skb_header(n
, skb
);
751 EXPORT_SYMBOL(pskb_copy
);
754 * pskb_expand_head - reallocate header of &sk_buff
755 * @skb: buffer to reallocate
756 * @nhead: room to add at head
757 * @ntail: room to add at tail
758 * @gfp_mask: allocation priority
760 * Expands (or creates identical copy, if &nhead and &ntail are zero)
761 * header of skb. &sk_buff itself is not changed. &sk_buff MUST have
762 * reference count of 1. Returns zero in the case of success or error,
763 * if expansion failed. In the last case, &sk_buff is not changed.
765 * All the pointers pointing into skb header may change and must be
766 * reloaded after call to this function.
769 int pskb_expand_head(struct sk_buff
*skb
, int nhead
, int ntail
,
774 #ifdef NET_SKBUFF_DATA_USES_OFFSET
775 int size
= nhead
+ skb
->end
+ ntail
;
777 int size
= nhead
+ (skb
->end
- skb
->head
) + ntail
;
786 size
= SKB_DATA_ALIGN(size
);
788 data
= kmalloc(size
+ sizeof(struct skb_shared_info
), gfp_mask
);
792 /* Copy only real data... and, alas, header. This should be
793 * optimized for the cases when header is void. */
794 #ifdef NET_SKBUFF_DATA_USES_OFFSET
795 memcpy(data
+ nhead
, skb
->head
, skb
->tail
);
797 memcpy(data
+ nhead
, skb
->head
, skb
->tail
- skb
->head
);
799 memcpy(data
+ size
, skb_end_pointer(skb
),
800 sizeof(struct skb_shared_info
));
802 for (i
= 0; i
< skb_shinfo(skb
)->nr_frags
; i
++)
803 get_page(skb_shinfo(skb
)->frags
[i
].page
);
805 if (skb_shinfo(skb
)->frag_list
)
806 skb_clone_fraglist(skb
);
808 skb_release_data(skb
);
810 off
= (data
+ nhead
) - skb
->head
;
814 #ifdef NET_SKBUFF_DATA_USES_OFFSET
818 skb
->end
= skb
->head
+ size
;
820 /* {transport,network,mac}_header and tail are relative to skb->head */
822 skb
->transport_header
+= off
;
823 skb
->network_header
+= off
;
824 skb
->mac_header
+= off
;
825 skb
->csum_start
+= nhead
;
829 atomic_set(&skb_shinfo(skb
)->dataref
, 1);
835 EXPORT_SYMBOL(pskb_expand_head
);
837 /* Make private copy of skb with writable head and some headroom */
839 struct sk_buff
*skb_realloc_headroom(struct sk_buff
*skb
, unsigned int headroom
)
841 struct sk_buff
*skb2
;
842 int delta
= headroom
- skb_headroom(skb
);
845 skb2
= pskb_copy(skb
, GFP_ATOMIC
);
847 skb2
= skb_clone(skb
, GFP_ATOMIC
);
848 if (skb2
&& pskb_expand_head(skb2
, SKB_DATA_ALIGN(delta
), 0,
856 EXPORT_SYMBOL(skb_realloc_headroom
);
859 * skb_copy_expand - copy and expand sk_buff
860 * @skb: buffer to copy
861 * @newheadroom: new free bytes at head
862 * @newtailroom: new free bytes at tail
863 * @gfp_mask: allocation priority
865 * Make a copy of both an &sk_buff and its data and while doing so
866 * allocate additional space.
868 * This is used when the caller wishes to modify the data and needs a
869 * private copy of the data to alter as well as more space for new fields.
870 * Returns %NULL on failure or the pointer to the buffer
871 * on success. The returned buffer has a reference count of 1.
873 * You must pass %GFP_ATOMIC as the allocation priority if this function
874 * is called from an interrupt.
876 struct sk_buff
*skb_copy_expand(const struct sk_buff
*skb
,
877 int newheadroom
, int newtailroom
,
881 * Allocate the copy buffer
883 struct sk_buff
*n
= alloc_skb(newheadroom
+ skb
->len
+ newtailroom
,
885 int oldheadroom
= skb_headroom(skb
);
886 int head_copy_len
, head_copy_off
;
892 skb_reserve(n
, newheadroom
);
894 /* Set the tail pointer and length */
895 skb_put(n
, skb
->len
);
897 head_copy_len
= oldheadroom
;
899 if (newheadroom
<= head_copy_len
)
900 head_copy_len
= newheadroom
;
902 head_copy_off
= newheadroom
- head_copy_len
;
904 /* Copy the linear header and data. */
905 if (skb_copy_bits(skb
, -head_copy_len
, n
->head
+ head_copy_off
,
906 skb
->len
+ head_copy_len
))
909 copy_skb_header(n
, skb
);
911 off
= newheadroom
- oldheadroom
;
912 n
->csum_start
+= off
;
913 #ifdef NET_SKBUFF_DATA_USES_OFFSET
914 n
->transport_header
+= off
;
915 n
->network_header
+= off
;
916 n
->mac_header
+= off
;
921 EXPORT_SYMBOL(skb_copy_expand
);
924 * skb_pad - zero pad the tail of an skb
925 * @skb: buffer to pad
928 * Ensure that a buffer is followed by a padding area that is zero
929 * filled. Used by network drivers which may DMA or transfer data
930 * beyond the buffer end onto the wire.
932 * May return error in out of memory cases. The skb is freed on error.
935 int skb_pad(struct sk_buff
*skb
, int pad
)
940 /* If the skbuff is non linear tailroom is always zero.. */
941 if (!skb_cloned(skb
) && skb_tailroom(skb
) >= pad
) {
942 memset(skb
->data
+skb
->len
, 0, pad
);
946 ntail
= skb
->data_len
+ pad
- (skb
->end
- skb
->tail
);
947 if (likely(skb_cloned(skb
) || ntail
> 0)) {
948 err
= pskb_expand_head(skb
, 0, ntail
, GFP_ATOMIC
);
953 /* FIXME: The use of this function with non-linear skb's really needs
956 err
= skb_linearize(skb
);
960 memset(skb
->data
+ skb
->len
, 0, pad
);
967 EXPORT_SYMBOL(skb_pad
);
970 * skb_put - add data to a buffer
971 * @skb: buffer to use
972 * @len: amount of data to add
974 * This function extends the used data area of the buffer. If this would
975 * exceed the total buffer size the kernel will panic. A pointer to the
976 * first byte of the extra data is returned.
978 unsigned char *skb_put(struct sk_buff
*skb
, unsigned int len
)
980 unsigned char *tmp
= skb_tail_pointer(skb
);
981 SKB_LINEAR_ASSERT(skb
);
984 if (unlikely(skb
->tail
> skb
->end
))
985 skb_over_panic(skb
, len
, __builtin_return_address(0));
988 EXPORT_SYMBOL(skb_put
);
991 * skb_push - add data to the start of a buffer
992 * @skb: buffer to use
993 * @len: amount of data to add
995 * This function extends the used data area of the buffer at the buffer
996 * start. If this would exceed the total buffer headroom the kernel will
997 * panic. A pointer to the first byte of the extra data is returned.
999 unsigned char *skb_push(struct sk_buff
*skb
, unsigned int len
)
1003 if (unlikely(skb
->data
<skb
->head
))
1004 skb_under_panic(skb
, len
, __builtin_return_address(0));
1007 EXPORT_SYMBOL(skb_push
);
1010 * skb_pull - remove data from the start of a buffer
1011 * @skb: buffer to use
1012 * @len: amount of data to remove
1014 * This function removes data from the start of a buffer, returning
1015 * the memory to the headroom. A pointer to the next data in the buffer
1016 * is returned. Once the data has been pulled future pushes will overwrite
1019 unsigned char *skb_pull(struct sk_buff
*skb
, unsigned int len
)
1021 return unlikely(len
> skb
->len
) ? NULL
: __skb_pull(skb
, len
);
1023 EXPORT_SYMBOL(skb_pull
);
1026 * skb_trim - remove end from a buffer
1027 * @skb: buffer to alter
1030 * Cut the length of a buffer down by removing data from the tail. If
1031 * the buffer is already under the length specified it is not modified.
1032 * The skb must be linear.
1034 void skb_trim(struct sk_buff
*skb
, unsigned int len
)
1037 __skb_trim(skb
, len
);
1039 EXPORT_SYMBOL(skb_trim
);
1041 /* Trims skb to length len. It can change skb pointers.
1044 int ___pskb_trim(struct sk_buff
*skb
, unsigned int len
)
1046 struct sk_buff
**fragp
;
1047 struct sk_buff
*frag
;
1048 int offset
= skb_headlen(skb
);
1049 int nfrags
= skb_shinfo(skb
)->nr_frags
;
1053 if (skb_cloned(skb
) &&
1054 unlikely((err
= pskb_expand_head(skb
, 0, 0, GFP_ATOMIC
))))
1061 for (; i
< nfrags
; i
++) {
1062 int end
= offset
+ skb_shinfo(skb
)->frags
[i
].size
;
1069 skb_shinfo(skb
)->frags
[i
++].size
= len
- offset
;
1072 skb_shinfo(skb
)->nr_frags
= i
;
1074 for (; i
< nfrags
; i
++)
1075 put_page(skb_shinfo(skb
)->frags
[i
].page
);
1077 if (skb_shinfo(skb
)->frag_list
)
1078 skb_drop_fraglist(skb
);
1082 for (fragp
= &skb_shinfo(skb
)->frag_list
; (frag
= *fragp
);
1083 fragp
= &frag
->next
) {
1084 int end
= offset
+ frag
->len
;
1086 if (skb_shared(frag
)) {
1087 struct sk_buff
*nfrag
;
1089 nfrag
= skb_clone(frag
, GFP_ATOMIC
);
1090 if (unlikely(!nfrag
))
1093 nfrag
->next
= frag
->next
;
1105 unlikely((err
= pskb_trim(frag
, len
- offset
))))
1109 skb_drop_list(&frag
->next
);
1114 if (len
> skb_headlen(skb
)) {
1115 skb
->data_len
-= skb
->len
- len
;
1120 skb_set_tail_pointer(skb
, len
);
1125 EXPORT_SYMBOL(___pskb_trim
);
1128 * __pskb_pull_tail - advance tail of skb header
1129 * @skb: buffer to reallocate
1130 * @delta: number of bytes to advance tail
1132 * The function makes a sense only on a fragmented &sk_buff,
1133 * it expands header moving its tail forward and copying necessary
1134 * data from fragmented part.
1136 * &sk_buff MUST have reference count of 1.
1138 * Returns %NULL (and &sk_buff does not change) if pull failed
1139 * or value of new tail of skb in the case of success.
1141 * All the pointers pointing into skb header may change and must be
1142 * reloaded after call to this function.
1145 /* Moves tail of skb head forward, copying data from fragmented part,
1146 * when it is necessary.
1147 * 1. It may fail due to malloc failure.
1148 * 2. It may change skb pointers.
1150 * It is pretty complicated. Luckily, it is called only in exceptional cases.
1152 unsigned char *__pskb_pull_tail(struct sk_buff
*skb
, int delta
)
1154 /* If skb has not enough free space at tail, get new one
1155 * plus 128 bytes for future expansions. If we have enough
1156 * room at tail, reallocate without expansion only if skb is cloned.
1158 int i
, k
, eat
= (skb
->tail
+ delta
) - skb
->end
;
1160 if (eat
> 0 || skb_cloned(skb
)) {
1161 if (pskb_expand_head(skb
, 0, eat
> 0 ? eat
+ 128 : 0,
1166 if (skb_copy_bits(skb
, skb_headlen(skb
), skb_tail_pointer(skb
), delta
))
1169 /* Optimization: no fragments, no reasons to preestimate
1170 * size of pulled pages. Superb.
1172 if (!skb_shinfo(skb
)->frag_list
)
1175 /* Estimate size of pulled pages. */
1177 for (i
= 0; i
< skb_shinfo(skb
)->nr_frags
; i
++) {
1178 if (skb_shinfo(skb
)->frags
[i
].size
>= eat
)
1180 eat
-= skb_shinfo(skb
)->frags
[i
].size
;
1183 /* If we need update frag list, we are in troubles.
1184 * Certainly, it possible to add an offset to skb data,
1185 * but taking into account that pulling is expected to
1186 * be very rare operation, it is worth to fight against
1187 * further bloating skb head and crucify ourselves here instead.
1188 * Pure masohism, indeed. 8)8)
1191 struct sk_buff
*list
= skb_shinfo(skb
)->frag_list
;
1192 struct sk_buff
*clone
= NULL
;
1193 struct sk_buff
*insp
= NULL
;
1198 if (list
->len
<= eat
) {
1199 /* Eaten as whole. */
1204 /* Eaten partially. */
1206 if (skb_shared(list
)) {
1207 /* Sucks! We need to fork list. :-( */
1208 clone
= skb_clone(list
, GFP_ATOMIC
);
1214 /* This may be pulled without
1218 if (!pskb_pull(list
, eat
)) {
1227 /* Free pulled out fragments. */
1228 while ((list
= skb_shinfo(skb
)->frag_list
) != insp
) {
1229 skb_shinfo(skb
)->frag_list
= list
->next
;
1232 /* And insert new clone at head. */
1235 skb_shinfo(skb
)->frag_list
= clone
;
1238 /* Success! Now we may commit changes to skb data. */
1243 for (i
= 0; i
< skb_shinfo(skb
)->nr_frags
; i
++) {
1244 if (skb_shinfo(skb
)->frags
[i
].size
<= eat
) {
1245 put_page(skb_shinfo(skb
)->frags
[i
].page
);
1246 eat
-= skb_shinfo(skb
)->frags
[i
].size
;
1248 skb_shinfo(skb
)->frags
[k
] = skb_shinfo(skb
)->frags
[i
];
1250 skb_shinfo(skb
)->frags
[k
].page_offset
+= eat
;
1251 skb_shinfo(skb
)->frags
[k
].size
-= eat
;
1257 skb_shinfo(skb
)->nr_frags
= k
;
1260 skb
->data_len
-= delta
;
1262 return skb_tail_pointer(skb
);
1264 EXPORT_SYMBOL(__pskb_pull_tail
);
1266 /* Copy some data bits from skb to kernel buffer. */
1268 int skb_copy_bits(const struct sk_buff
*skb
, int offset
, void *to
, int len
)
1271 int start
= skb_headlen(skb
);
1273 if (offset
> (int)skb
->len
- len
)
1277 if ((copy
= start
- offset
) > 0) {
1280 skb_copy_from_linear_data_offset(skb
, offset
, to
, copy
);
1281 if ((len
-= copy
) == 0)
1287 for (i
= 0; i
< skb_shinfo(skb
)->nr_frags
; i
++) {
1290 WARN_ON(start
> offset
+ len
);
1292 end
= start
+ skb_shinfo(skb
)->frags
[i
].size
;
1293 if ((copy
= end
- offset
) > 0) {
1299 vaddr
= kmap_skb_frag(&skb_shinfo(skb
)->frags
[i
]);
1301 vaddr
+ skb_shinfo(skb
)->frags
[i
].page_offset
+
1302 offset
- start
, copy
);
1303 kunmap_skb_frag(vaddr
);
1305 if ((len
-= copy
) == 0)
1313 if (skb_shinfo(skb
)->frag_list
) {
1314 struct sk_buff
*list
= skb_shinfo(skb
)->frag_list
;
1316 for (; list
; list
= list
->next
) {
1319 WARN_ON(start
> offset
+ len
);
1321 end
= start
+ list
->len
;
1322 if ((copy
= end
- offset
) > 0) {
1325 if (skb_copy_bits(list
, offset
- start
,
1328 if ((len
-= copy
) == 0)
1342 EXPORT_SYMBOL(skb_copy_bits
);
1345 * Callback from splice_to_pipe(), if we need to release some pages
1346 * at the end of the spd in case we error'ed out in filling the pipe.
1348 static void sock_spd_release(struct splice_pipe_desc
*spd
, unsigned int i
)
1350 put_page(spd
->pages
[i
]);
1353 static inline struct page
*linear_to_page(struct page
*page
, unsigned int *len
,
1354 unsigned int *offset
,
1355 struct sk_buff
*skb
)
1357 struct sock
*sk
= skb
->sk
;
1358 struct page
*p
= sk
->sk_sndmsg_page
;
1363 p
= sk
->sk_sndmsg_page
= alloc_pages(sk
->sk_allocation
, 0);
1367 off
= sk
->sk_sndmsg_off
= 0;
1368 /* hold one ref to this page until it's full */
1372 off
= sk
->sk_sndmsg_off
;
1373 mlen
= PAGE_SIZE
- off
;
1374 if (mlen
< 64 && mlen
< *len
) {
1379 *len
= min_t(unsigned int, *len
, mlen
);
1382 memcpy(page_address(p
) + off
, page_address(page
) + *offset
, *len
);
1383 sk
->sk_sndmsg_off
+= *len
;
1391 * Fill page/offset/length into spd, if it can hold more pages.
1393 static inline int spd_fill_page(struct splice_pipe_desc
*spd
, struct page
*page
,
1394 unsigned int *len
, unsigned int offset
,
1395 struct sk_buff
*skb
, int linear
)
1397 if (unlikely(spd
->nr_pages
== PIPE_BUFFERS
))
1401 page
= linear_to_page(page
, len
, &offset
, skb
);
1407 spd
->pages
[spd
->nr_pages
] = page
;
1408 spd
->partial
[spd
->nr_pages
].len
= *len
;
1409 spd
->partial
[spd
->nr_pages
].offset
= offset
;
1415 static inline void __segment_seek(struct page
**page
, unsigned int *poff
,
1416 unsigned int *plen
, unsigned int off
)
1421 n
= *poff
/ PAGE_SIZE
;
1423 *page
= nth_page(*page
, n
);
1425 *poff
= *poff
% PAGE_SIZE
;
1429 static inline int __splice_segment(struct page
*page
, unsigned int poff
,
1430 unsigned int plen
, unsigned int *off
,
1431 unsigned int *len
, struct sk_buff
*skb
,
1432 struct splice_pipe_desc
*spd
, int linear
)
1437 /* skip this segment if already processed */
1443 /* ignore any bits we already processed */
1445 __segment_seek(&page
, &poff
, &plen
, *off
);
1450 unsigned int flen
= min(*len
, plen
);
1452 /* the linear region may spread across several pages */
1453 flen
= min_t(unsigned int, flen
, PAGE_SIZE
- poff
);
1455 if (spd_fill_page(spd
, page
, &flen
, poff
, skb
, linear
))
1458 __segment_seek(&page
, &poff
, &plen
, flen
);
1461 } while (*len
&& plen
);
1467 * Map linear and fragment data from the skb to spd. It reports failure if the
1468 * pipe is full or if we already spliced the requested length.
1470 static int __skb_splice_bits(struct sk_buff
*skb
, unsigned int *offset
,
1472 struct splice_pipe_desc
*spd
)
1477 * map the linear part
1479 if (__splice_segment(virt_to_page(skb
->data
),
1480 (unsigned long) skb
->data
& (PAGE_SIZE
- 1),
1482 offset
, len
, skb
, spd
, 1))
1486 * then map the fragments
1488 for (seg
= 0; seg
< skb_shinfo(skb
)->nr_frags
; seg
++) {
1489 const skb_frag_t
*f
= &skb_shinfo(skb
)->frags
[seg
];
1491 if (__splice_segment(f
->page
, f
->page_offset
, f
->size
,
1492 offset
, len
, skb
, spd
, 0))
1500 * Map data from the skb to a pipe. Should handle both the linear part,
1501 * the fragments, and the frag list. It does NOT handle frag lists within
1502 * the frag list, if such a thing exists. We'd probably need to recurse to
1503 * handle that cleanly.
1505 int skb_splice_bits(struct sk_buff
*skb
, unsigned int offset
,
1506 struct pipe_inode_info
*pipe
, unsigned int tlen
,
1509 struct partial_page partial
[PIPE_BUFFERS
];
1510 struct page
*pages
[PIPE_BUFFERS
];
1511 struct splice_pipe_desc spd
= {
1515 .ops
= &sock_pipe_buf_ops
,
1516 .spd_release
= sock_spd_release
,
1520 * __skb_splice_bits() only fails if the output has no room left,
1521 * so no point in going over the frag_list for the error case.
1523 if (__skb_splice_bits(skb
, &offset
, &tlen
, &spd
))
1529 * now see if we have a frag_list to map
1531 if (skb_shinfo(skb
)->frag_list
) {
1532 struct sk_buff
*list
= skb_shinfo(skb
)->frag_list
;
1534 for (; list
&& tlen
; list
= list
->next
) {
1535 if (__skb_splice_bits(list
, &offset
, &tlen
, &spd
))
1542 struct sock
*sk
= skb
->sk
;
1546 * Drop the socket lock, otherwise we have reverse
1547 * locking dependencies between sk_lock and i_mutex
1548 * here as compared to sendfile(). We enter here
1549 * with the socket lock held, and splice_to_pipe() will
1550 * grab the pipe inode lock. For sendfile() emulation,
1551 * we call into ->sendpage() with the i_mutex lock held
1552 * and networking will grab the socket lock.
1555 ret
= splice_to_pipe(pipe
, &spd
);
1564 * skb_store_bits - store bits from kernel buffer to skb
1565 * @skb: destination buffer
1566 * @offset: offset in destination
1567 * @from: source buffer
1568 * @len: number of bytes to copy
1570 * Copy the specified number of bytes from the source buffer to the
1571 * destination skb. This function handles all the messy bits of
1572 * traversing fragment lists and such.
1575 int skb_store_bits(struct sk_buff
*skb
, int offset
, const void *from
, int len
)
1578 int start
= skb_headlen(skb
);
1580 if (offset
> (int)skb
->len
- len
)
1583 if ((copy
= start
- offset
) > 0) {
1586 skb_copy_to_linear_data_offset(skb
, offset
, from
, copy
);
1587 if ((len
-= copy
) == 0)
1593 for (i
= 0; i
< skb_shinfo(skb
)->nr_frags
; i
++) {
1594 skb_frag_t
*frag
= &skb_shinfo(skb
)->frags
[i
];
1597 WARN_ON(start
> offset
+ len
);
1599 end
= start
+ frag
->size
;
1600 if ((copy
= end
- offset
) > 0) {
1606 vaddr
= kmap_skb_frag(frag
);
1607 memcpy(vaddr
+ frag
->page_offset
+ offset
- start
,
1609 kunmap_skb_frag(vaddr
);
1611 if ((len
-= copy
) == 0)
1619 if (skb_shinfo(skb
)->frag_list
) {
1620 struct sk_buff
*list
= skb_shinfo(skb
)->frag_list
;
1622 for (; list
; list
= list
->next
) {
1625 WARN_ON(start
> offset
+ len
);
1627 end
= start
+ list
->len
;
1628 if ((copy
= end
- offset
) > 0) {
1631 if (skb_store_bits(list
, offset
- start
,
1634 if ((len
-= copy
) == 0)
1648 EXPORT_SYMBOL(skb_store_bits
);
1650 /* Checksum skb data. */
1652 __wsum
skb_checksum(const struct sk_buff
*skb
, int offset
,
1653 int len
, __wsum csum
)
1655 int start
= skb_headlen(skb
);
1656 int i
, copy
= start
- offset
;
1659 /* Checksum header. */
1663 csum
= csum_partial(skb
->data
+ offset
, copy
, csum
);
1664 if ((len
-= copy
) == 0)
1670 for (i
= 0; i
< skb_shinfo(skb
)->nr_frags
; i
++) {
1673 WARN_ON(start
> offset
+ len
);
1675 end
= start
+ skb_shinfo(skb
)->frags
[i
].size
;
1676 if ((copy
= end
- offset
) > 0) {
1679 skb_frag_t
*frag
= &skb_shinfo(skb
)->frags
[i
];
1683 vaddr
= kmap_skb_frag(frag
);
1684 csum2
= csum_partial(vaddr
+ frag
->page_offset
+
1685 offset
- start
, copy
, 0);
1686 kunmap_skb_frag(vaddr
);
1687 csum
= csum_block_add(csum
, csum2
, pos
);
1696 if (skb_shinfo(skb
)->frag_list
) {
1697 struct sk_buff
*list
= skb_shinfo(skb
)->frag_list
;
1699 for (; list
; list
= list
->next
) {
1702 WARN_ON(start
> offset
+ len
);
1704 end
= start
+ list
->len
;
1705 if ((copy
= end
- offset
) > 0) {
1709 csum2
= skb_checksum(list
, offset
- start
,
1711 csum
= csum_block_add(csum
, csum2
, pos
);
1712 if ((len
-= copy
) == 0)
1724 EXPORT_SYMBOL(skb_checksum
);
1726 /* Both of above in one bottle. */
1728 __wsum
skb_copy_and_csum_bits(const struct sk_buff
*skb
, int offset
,
1729 u8
*to
, int len
, __wsum csum
)
1731 int start
= skb_headlen(skb
);
1732 int i
, copy
= start
- offset
;
1739 csum
= csum_partial_copy_nocheck(skb
->data
+ offset
, to
,
1741 if ((len
-= copy
) == 0)
1748 for (i
= 0; i
< skb_shinfo(skb
)->nr_frags
; i
++) {
1751 WARN_ON(start
> offset
+ len
);
1753 end
= start
+ skb_shinfo(skb
)->frags
[i
].size
;
1754 if ((copy
= end
- offset
) > 0) {
1757 skb_frag_t
*frag
= &skb_shinfo(skb
)->frags
[i
];
1761 vaddr
= kmap_skb_frag(frag
);
1762 csum2
= csum_partial_copy_nocheck(vaddr
+
1766 kunmap_skb_frag(vaddr
);
1767 csum
= csum_block_add(csum
, csum2
, pos
);
1777 if (skb_shinfo(skb
)->frag_list
) {
1778 struct sk_buff
*list
= skb_shinfo(skb
)->frag_list
;
1780 for (; list
; list
= list
->next
) {
1784 WARN_ON(start
> offset
+ len
);
1786 end
= start
+ list
->len
;
1787 if ((copy
= end
- offset
) > 0) {
1790 csum2
= skb_copy_and_csum_bits(list
,
1793 csum
= csum_block_add(csum
, csum2
, pos
);
1794 if ((len
-= copy
) == 0)
1806 EXPORT_SYMBOL(skb_copy_and_csum_bits
);
1808 void skb_copy_and_csum_dev(const struct sk_buff
*skb
, u8
*to
)
1813 if (skb
->ip_summed
== CHECKSUM_PARTIAL
)
1814 csstart
= skb
->csum_start
- skb_headroom(skb
);
1816 csstart
= skb_headlen(skb
);
1818 BUG_ON(csstart
> skb_headlen(skb
));
1820 skb_copy_from_linear_data(skb
, to
, csstart
);
1823 if (csstart
!= skb
->len
)
1824 csum
= skb_copy_and_csum_bits(skb
, csstart
, to
+ csstart
,
1825 skb
->len
- csstart
, 0);
1827 if (skb
->ip_summed
== CHECKSUM_PARTIAL
) {
1828 long csstuff
= csstart
+ skb
->csum_offset
;
1830 *((__sum16
*)(to
+ csstuff
)) = csum_fold(csum
);
1833 EXPORT_SYMBOL(skb_copy_and_csum_dev
);
1836 * skb_dequeue - remove from the head of the queue
1837 * @list: list to dequeue from
1839 * Remove the head of the list. The list lock is taken so the function
1840 * may be used safely with other locking list functions. The head item is
1841 * returned or %NULL if the list is empty.
1844 struct sk_buff
*skb_dequeue(struct sk_buff_head
*list
)
1846 unsigned long flags
;
1847 struct sk_buff
*result
;
1849 spin_lock_irqsave(&list
->lock
, flags
);
1850 result
= __skb_dequeue(list
);
1851 spin_unlock_irqrestore(&list
->lock
, flags
);
1854 EXPORT_SYMBOL(skb_dequeue
);
1857 * skb_dequeue_tail - remove from the tail of the queue
1858 * @list: list to dequeue from
1860 * Remove the tail of the list. The list lock is taken so the function
1861 * may be used safely with other locking list functions. The tail item is
1862 * returned or %NULL if the list is empty.
1864 struct sk_buff
*skb_dequeue_tail(struct sk_buff_head
*list
)
1866 unsigned long flags
;
1867 struct sk_buff
*result
;
1869 spin_lock_irqsave(&list
->lock
, flags
);
1870 result
= __skb_dequeue_tail(list
);
1871 spin_unlock_irqrestore(&list
->lock
, flags
);
1874 EXPORT_SYMBOL(skb_dequeue_tail
);
1877 * skb_queue_purge - empty a list
1878 * @list: list to empty
1880 * Delete all buffers on an &sk_buff list. Each buffer is removed from
1881 * the list and one reference dropped. This function takes the list
1882 * lock and is atomic with respect to other list locking functions.
1884 void skb_queue_purge(struct sk_buff_head
*list
)
1886 struct sk_buff
*skb
;
1887 while ((skb
= skb_dequeue(list
)) != NULL
)
1890 EXPORT_SYMBOL(skb_queue_purge
);
1893 * skb_queue_head - queue a buffer at the list head
1894 * @list: list to use
1895 * @newsk: buffer to queue
1897 * Queue a buffer at the start of the list. This function takes the
1898 * list lock and can be used safely with other locking &sk_buff functions
1901 * A buffer cannot be placed on two lists at the same time.
1903 void skb_queue_head(struct sk_buff_head
*list
, struct sk_buff
*newsk
)
1905 unsigned long flags
;
1907 spin_lock_irqsave(&list
->lock
, flags
);
1908 __skb_queue_head(list
, newsk
);
1909 spin_unlock_irqrestore(&list
->lock
, flags
);
1911 EXPORT_SYMBOL(skb_queue_head
);
1914 * skb_queue_tail - queue a buffer at the list tail
1915 * @list: list to use
1916 * @newsk: buffer to queue
1918 * Queue a buffer at the tail of the list. This function takes the
1919 * list lock and can be used safely with other locking &sk_buff functions
1922 * A buffer cannot be placed on two lists at the same time.
1924 void skb_queue_tail(struct sk_buff_head
*list
, struct sk_buff
*newsk
)
1926 unsigned long flags
;
1928 spin_lock_irqsave(&list
->lock
, flags
);
1929 __skb_queue_tail(list
, newsk
);
1930 spin_unlock_irqrestore(&list
->lock
, flags
);
1932 EXPORT_SYMBOL(skb_queue_tail
);
1935 * skb_unlink - remove a buffer from a list
1936 * @skb: buffer to remove
1937 * @list: list to use
1939 * Remove a packet from a list. The list locks are taken and this
1940 * function is atomic with respect to other list locked calls
1942 * You must know what list the SKB is on.
1944 void skb_unlink(struct sk_buff
*skb
, struct sk_buff_head
*list
)
1946 unsigned long flags
;
1948 spin_lock_irqsave(&list
->lock
, flags
);
1949 __skb_unlink(skb
, list
);
1950 spin_unlock_irqrestore(&list
->lock
, flags
);
1952 EXPORT_SYMBOL(skb_unlink
);
1955 * skb_append - append a buffer
1956 * @old: buffer to insert after
1957 * @newsk: buffer to insert
1958 * @list: list to use
1960 * Place a packet after a given packet in a list. The list locks are taken
1961 * and this function is atomic with respect to other list locked calls.
1962 * A buffer cannot be placed on two lists at the same time.
1964 void skb_append(struct sk_buff
*old
, struct sk_buff
*newsk
, struct sk_buff_head
*list
)
1966 unsigned long flags
;
1968 spin_lock_irqsave(&list
->lock
, flags
);
1969 __skb_queue_after(list
, old
, newsk
);
1970 spin_unlock_irqrestore(&list
->lock
, flags
);
1972 EXPORT_SYMBOL(skb_append
);
1975 * skb_insert - insert a buffer
1976 * @old: buffer to insert before
1977 * @newsk: buffer to insert
1978 * @list: list to use
1980 * Place a packet before a given packet in a list. The list locks are
1981 * taken and this function is atomic with respect to other list locked
1984 * A buffer cannot be placed on two lists at the same time.
1986 void skb_insert(struct sk_buff
*old
, struct sk_buff
*newsk
, struct sk_buff_head
*list
)
1988 unsigned long flags
;
1990 spin_lock_irqsave(&list
->lock
, flags
);
1991 __skb_insert(newsk
, old
->prev
, old
, list
);
1992 spin_unlock_irqrestore(&list
->lock
, flags
);
1994 EXPORT_SYMBOL(skb_insert
);
1996 static inline void skb_split_inside_header(struct sk_buff
*skb
,
1997 struct sk_buff
* skb1
,
1998 const u32 len
, const int pos
)
2002 skb_copy_from_linear_data_offset(skb
, len
, skb_put(skb1
, pos
- len
),
2004 /* And move data appendix as is. */
2005 for (i
= 0; i
< skb_shinfo(skb
)->nr_frags
; i
++)
2006 skb_shinfo(skb1
)->frags
[i
] = skb_shinfo(skb
)->frags
[i
];
2008 skb_shinfo(skb1
)->nr_frags
= skb_shinfo(skb
)->nr_frags
;
2009 skb_shinfo(skb
)->nr_frags
= 0;
2010 skb1
->data_len
= skb
->data_len
;
2011 skb1
->len
+= skb1
->data_len
;
2014 skb_set_tail_pointer(skb
, len
);
2017 static inline void skb_split_no_header(struct sk_buff
*skb
,
2018 struct sk_buff
* skb1
,
2019 const u32 len
, int pos
)
2022 const int nfrags
= skb_shinfo(skb
)->nr_frags
;
2024 skb_shinfo(skb
)->nr_frags
= 0;
2025 skb1
->len
= skb1
->data_len
= skb
->len
- len
;
2027 skb
->data_len
= len
- pos
;
2029 for (i
= 0; i
< nfrags
; i
++) {
2030 int size
= skb_shinfo(skb
)->frags
[i
].size
;
2032 if (pos
+ size
> len
) {
2033 skb_shinfo(skb1
)->frags
[k
] = skb_shinfo(skb
)->frags
[i
];
2037 * We have two variants in this case:
2038 * 1. Move all the frag to the second
2039 * part, if it is possible. F.e.
2040 * this approach is mandatory for TUX,
2041 * where splitting is expensive.
2042 * 2. Split is accurately. We make this.
2044 get_page(skb_shinfo(skb
)->frags
[i
].page
);
2045 skb_shinfo(skb1
)->frags
[0].page_offset
+= len
- pos
;
2046 skb_shinfo(skb1
)->frags
[0].size
-= len
- pos
;
2047 skb_shinfo(skb
)->frags
[i
].size
= len
- pos
;
2048 skb_shinfo(skb
)->nr_frags
++;
2052 skb_shinfo(skb
)->nr_frags
++;
2055 skb_shinfo(skb1
)->nr_frags
= k
;
2059 * skb_split - Split fragmented skb to two parts at length len.
2060 * @skb: the buffer to split
2061 * @skb1: the buffer to receive the second part
2062 * @len: new length for skb
2064 void skb_split(struct sk_buff
*skb
, struct sk_buff
*skb1
, const u32 len
)
2066 int pos
= skb_headlen(skb
);
2068 if (len
< pos
) /* Split line is inside header. */
2069 skb_split_inside_header(skb
, skb1
, len
, pos
);
2070 else /* Second chunk has no header, nothing to copy. */
2071 skb_split_no_header(skb
, skb1
, len
, pos
);
2073 EXPORT_SYMBOL(skb_split
);
2075 /* Shifting from/to a cloned skb is a no-go.
2077 * Caller cannot keep skb_shinfo related pointers past calling here!
2079 static int skb_prepare_for_shift(struct sk_buff
*skb
)
2081 return skb_cloned(skb
) && pskb_expand_head(skb
, 0, 0, GFP_ATOMIC
);
2085 * skb_shift - Shifts paged data partially from skb to another
2086 * @tgt: buffer into which tail data gets added
2087 * @skb: buffer from which the paged data comes from
2088 * @shiftlen: shift up to this many bytes
2090 * Attempts to shift up to shiftlen worth of bytes, which may be less than
2091 * the length of the skb, from tgt to skb. Returns number bytes shifted.
2092 * It's up to caller to free skb if everything was shifted.
2094 * If @tgt runs out of frags, the whole operation is aborted.
2096 * Skb cannot include anything else but paged data while tgt is allowed
2097 * to have non-paged data as well.
2099 * TODO: full sized shift could be optimized but that would need
2100 * specialized skb free'er to handle frags without up-to-date nr_frags.
2102 int skb_shift(struct sk_buff
*tgt
, struct sk_buff
*skb
, int shiftlen
)
2104 int from
, to
, merge
, todo
;
2105 struct skb_frag_struct
*fragfrom
, *fragto
;
2107 BUG_ON(shiftlen
> skb
->len
);
2108 BUG_ON(skb_headlen(skb
)); /* Would corrupt stream */
2112 to
= skb_shinfo(tgt
)->nr_frags
;
2113 fragfrom
= &skb_shinfo(skb
)->frags
[from
];
2115 /* Actual merge is delayed until the point when we know we can
2116 * commit all, so that we don't have to undo partial changes
2119 !skb_can_coalesce(tgt
, to
, fragfrom
->page
, fragfrom
->page_offset
)) {
2124 todo
-= fragfrom
->size
;
2126 if (skb_prepare_for_shift(skb
) ||
2127 skb_prepare_for_shift(tgt
))
2130 /* All previous frag pointers might be stale! */
2131 fragfrom
= &skb_shinfo(skb
)->frags
[from
];
2132 fragto
= &skb_shinfo(tgt
)->frags
[merge
];
2134 fragto
->size
+= shiftlen
;
2135 fragfrom
->size
-= shiftlen
;
2136 fragfrom
->page_offset
+= shiftlen
;
2144 /* Skip full, not-fitting skb to avoid expensive operations */
2145 if ((shiftlen
== skb
->len
) &&
2146 (skb_shinfo(skb
)->nr_frags
- from
) > (MAX_SKB_FRAGS
- to
))
2149 if (skb_prepare_for_shift(skb
) || skb_prepare_for_shift(tgt
))
2152 while ((todo
> 0) && (from
< skb_shinfo(skb
)->nr_frags
)) {
2153 if (to
== MAX_SKB_FRAGS
)
2156 fragfrom
= &skb_shinfo(skb
)->frags
[from
];
2157 fragto
= &skb_shinfo(tgt
)->frags
[to
];
2159 if (todo
>= fragfrom
->size
) {
2160 *fragto
= *fragfrom
;
2161 todo
-= fragfrom
->size
;
2166 get_page(fragfrom
->page
);
2167 fragto
->page
= fragfrom
->page
;
2168 fragto
->page_offset
= fragfrom
->page_offset
;
2169 fragto
->size
= todo
;
2171 fragfrom
->page_offset
+= todo
;
2172 fragfrom
->size
-= todo
;
2180 /* Ready to "commit" this state change to tgt */
2181 skb_shinfo(tgt
)->nr_frags
= to
;
2184 fragfrom
= &skb_shinfo(skb
)->frags
[0];
2185 fragto
= &skb_shinfo(tgt
)->frags
[merge
];
2187 fragto
->size
+= fragfrom
->size
;
2188 put_page(fragfrom
->page
);
2191 /* Reposition in the original skb */
2193 while (from
< skb_shinfo(skb
)->nr_frags
)
2194 skb_shinfo(skb
)->frags
[to
++] = skb_shinfo(skb
)->frags
[from
++];
2195 skb_shinfo(skb
)->nr_frags
= to
;
2197 BUG_ON(todo
> 0 && !skb_shinfo(skb
)->nr_frags
);
2200 /* Most likely the tgt won't ever need its checksum anymore, skb on
2201 * the other hand might need it if it needs to be resent
2203 tgt
->ip_summed
= CHECKSUM_PARTIAL
;
2204 skb
->ip_summed
= CHECKSUM_PARTIAL
;
2206 /* Yak, is it really working this way? Some helper please? */
2207 skb
->len
-= shiftlen
;
2208 skb
->data_len
-= shiftlen
;
2209 skb
->truesize
-= shiftlen
;
2210 tgt
->len
+= shiftlen
;
2211 tgt
->data_len
+= shiftlen
;
2212 tgt
->truesize
+= shiftlen
;
2218 * skb_prepare_seq_read - Prepare a sequential read of skb data
2219 * @skb: the buffer to read
2220 * @from: lower offset of data to be read
2221 * @to: upper offset of data to be read
2222 * @st: state variable
2224 * Initializes the specified state variable. Must be called before
2225 * invoking skb_seq_read() for the first time.
2227 void skb_prepare_seq_read(struct sk_buff
*skb
, unsigned int from
,
2228 unsigned int to
, struct skb_seq_state
*st
)
2230 st
->lower_offset
= from
;
2231 st
->upper_offset
= to
;
2232 st
->root_skb
= st
->cur_skb
= skb
;
2233 st
->frag_idx
= st
->stepped_offset
= 0;
2234 st
->frag_data
= NULL
;
2236 EXPORT_SYMBOL(skb_prepare_seq_read
);
2239 * skb_seq_read - Sequentially read skb data
2240 * @consumed: number of bytes consumed by the caller so far
2241 * @data: destination pointer for data to be returned
2242 * @st: state variable
2244 * Reads a block of skb data at &consumed relative to the
2245 * lower offset specified to skb_prepare_seq_read(). Assigns
2246 * the head of the data block to &data and returns the length
2247 * of the block or 0 if the end of the skb data or the upper
2248 * offset has been reached.
2250 * The caller is not required to consume all of the data
2251 * returned, i.e. &consumed is typically set to the number
2252 * of bytes already consumed and the next call to
2253 * skb_seq_read() will return the remaining part of the block.
2255 * Note 1: The size of each block of data returned can be arbitary,
2256 * this limitation is the cost for zerocopy seqeuental
2257 * reads of potentially non linear data.
2259 * Note 2: Fragment lists within fragments are not implemented
2260 * at the moment, state->root_skb could be replaced with
2261 * a stack for this purpose.
2263 unsigned int skb_seq_read(unsigned int consumed
, const u8
**data
,
2264 struct skb_seq_state
*st
)
2266 unsigned int block_limit
, abs_offset
= consumed
+ st
->lower_offset
;
2269 if (unlikely(abs_offset
>= st
->upper_offset
))
2273 block_limit
= skb_headlen(st
->cur_skb
) + st
->stepped_offset
;
2275 if (abs_offset
< block_limit
) {
2276 *data
= st
->cur_skb
->data
+ (abs_offset
- st
->stepped_offset
);
2277 return block_limit
- abs_offset
;
2280 if (st
->frag_idx
== 0 && !st
->frag_data
)
2281 st
->stepped_offset
+= skb_headlen(st
->cur_skb
);
2283 while (st
->frag_idx
< skb_shinfo(st
->cur_skb
)->nr_frags
) {
2284 frag
= &skb_shinfo(st
->cur_skb
)->frags
[st
->frag_idx
];
2285 block_limit
= frag
->size
+ st
->stepped_offset
;
2287 if (abs_offset
< block_limit
) {
2289 st
->frag_data
= kmap_skb_frag(frag
);
2291 *data
= (u8
*) st
->frag_data
+ frag
->page_offset
+
2292 (abs_offset
- st
->stepped_offset
);
2294 return block_limit
- abs_offset
;
2297 if (st
->frag_data
) {
2298 kunmap_skb_frag(st
->frag_data
);
2299 st
->frag_data
= NULL
;
2303 st
->stepped_offset
+= frag
->size
;
2306 if (st
->frag_data
) {
2307 kunmap_skb_frag(st
->frag_data
);
2308 st
->frag_data
= NULL
;
2311 if (st
->root_skb
== st
->cur_skb
&&
2312 skb_shinfo(st
->root_skb
)->frag_list
) {
2313 st
->cur_skb
= skb_shinfo(st
->root_skb
)->frag_list
;
2316 } else if (st
->cur_skb
->next
) {
2317 st
->cur_skb
= st
->cur_skb
->next
;
2324 EXPORT_SYMBOL(skb_seq_read
);
2327 * skb_abort_seq_read - Abort a sequential read of skb data
2328 * @st: state variable
2330 * Must be called if skb_seq_read() was not called until it
2333 void skb_abort_seq_read(struct skb_seq_state
*st
)
2336 kunmap_skb_frag(st
->frag_data
);
2338 EXPORT_SYMBOL(skb_abort_seq_read
);
2340 #define TS_SKB_CB(state) ((struct skb_seq_state *) &((state)->cb))
2342 static unsigned int skb_ts_get_next_block(unsigned int offset
, const u8
**text
,
2343 struct ts_config
*conf
,
2344 struct ts_state
*state
)
2346 return skb_seq_read(offset
, text
, TS_SKB_CB(state
));
2349 static void skb_ts_finish(struct ts_config
*conf
, struct ts_state
*state
)
2351 skb_abort_seq_read(TS_SKB_CB(state
));
2355 * skb_find_text - Find a text pattern in skb data
2356 * @skb: the buffer to look in
2357 * @from: search offset
2359 * @config: textsearch configuration
2360 * @state: uninitialized textsearch state variable
2362 * Finds a pattern in the skb data according to the specified
2363 * textsearch configuration. Use textsearch_next() to retrieve
2364 * subsequent occurrences of the pattern. Returns the offset
2365 * to the first occurrence or UINT_MAX if no match was found.
2367 unsigned int skb_find_text(struct sk_buff
*skb
, unsigned int from
,
2368 unsigned int to
, struct ts_config
*config
,
2369 struct ts_state
*state
)
2373 config
->get_next_block
= skb_ts_get_next_block
;
2374 config
->finish
= skb_ts_finish
;
2376 skb_prepare_seq_read(skb
, from
, to
, TS_SKB_CB(state
));
2378 ret
= textsearch_find(config
, state
);
2379 return (ret
<= to
- from
? ret
: UINT_MAX
);
2381 EXPORT_SYMBOL(skb_find_text
);
2384 * skb_append_datato_frags: - append the user data to a skb
2385 * @sk: sock structure
2386 * @skb: skb structure to be appened with user data.
2387 * @getfrag: call back function to be used for getting the user data
2388 * @from: pointer to user message iov
2389 * @length: length of the iov message
2391 * Description: This procedure append the user data in the fragment part
2392 * of the skb if any page alloc fails user this procedure returns -ENOMEM
2394 int skb_append_datato_frags(struct sock
*sk
, struct sk_buff
*skb
,
2395 int (*getfrag
)(void *from
, char *to
, int offset
,
2396 int len
, int odd
, struct sk_buff
*skb
),
2397 void *from
, int length
)
2400 skb_frag_t
*frag
= NULL
;
2401 struct page
*page
= NULL
;
2407 /* Return error if we don't have space for new frag */
2408 frg_cnt
= skb_shinfo(skb
)->nr_frags
;
2409 if (frg_cnt
>= MAX_SKB_FRAGS
)
2412 /* allocate a new page for next frag */
2413 page
= alloc_pages(sk
->sk_allocation
, 0);
2415 /* If alloc_page fails just return failure and caller will
2416 * free previous allocated pages by doing kfree_skb()
2421 /* initialize the next frag */
2422 sk
->sk_sndmsg_page
= page
;
2423 sk
->sk_sndmsg_off
= 0;
2424 skb_fill_page_desc(skb
, frg_cnt
, page
, 0, 0);
2425 skb
->truesize
+= PAGE_SIZE
;
2426 atomic_add(PAGE_SIZE
, &sk
->sk_wmem_alloc
);
2428 /* get the new initialized frag */
2429 frg_cnt
= skb_shinfo(skb
)->nr_frags
;
2430 frag
= &skb_shinfo(skb
)->frags
[frg_cnt
- 1];
2432 /* copy the user data to page */
2433 left
= PAGE_SIZE
- frag
->page_offset
;
2434 copy
= (length
> left
)? left
: length
;
2436 ret
= getfrag(from
, (page_address(frag
->page
) +
2437 frag
->page_offset
+ frag
->size
),
2438 offset
, copy
, 0, skb
);
2442 /* copy was successful so update the size parameters */
2443 sk
->sk_sndmsg_off
+= copy
;
2446 skb
->data_len
+= copy
;
2450 } while (length
> 0);
2454 EXPORT_SYMBOL(skb_append_datato_frags
);
2457 * skb_pull_rcsum - pull skb and update receive checksum
2458 * @skb: buffer to update
2459 * @len: length of data pulled
2461 * This function performs an skb_pull on the packet and updates
2462 * the CHECKSUM_COMPLETE checksum. It should be used on
2463 * receive path processing instead of skb_pull unless you know
2464 * that the checksum difference is zero (e.g., a valid IP header)
2465 * or you are setting ip_summed to CHECKSUM_NONE.
2467 unsigned char *skb_pull_rcsum(struct sk_buff
*skb
, unsigned int len
)
2469 BUG_ON(len
> skb
->len
);
2471 BUG_ON(skb
->len
< skb
->data_len
);
2472 skb_postpull_rcsum(skb
, skb
->data
, len
);
2473 return skb
->data
+= len
;
2476 EXPORT_SYMBOL_GPL(skb_pull_rcsum
);
2479 * skb_segment - Perform protocol segmentation on skb.
2480 * @skb: buffer to segment
2481 * @features: features for the output path (see dev->features)
2483 * This function performs segmentation on the given skb. It returns
2484 * a pointer to the first in a list of new skbs for the segments.
2485 * In case of error it returns ERR_PTR(err).
2487 struct sk_buff
*skb_segment(struct sk_buff
*skb
, int features
)
2489 struct sk_buff
*segs
= NULL
;
2490 struct sk_buff
*tail
= NULL
;
2491 struct sk_buff
*fskb
= skb_shinfo(skb
)->frag_list
;
2492 unsigned int mss
= skb_shinfo(skb
)->gso_size
;
2493 unsigned int doffset
= skb
->data
- skb_mac_header(skb
);
2494 unsigned int offset
= doffset
;
2495 unsigned int headroom
;
2497 int sg
= features
& NETIF_F_SG
;
2498 int nfrags
= skb_shinfo(skb
)->nr_frags
;
2503 __skb_push(skb
, doffset
);
2504 headroom
= skb_headroom(skb
);
2505 pos
= skb_headlen(skb
);
2508 struct sk_buff
*nskb
;
2513 len
= skb
->len
- offset
;
2517 hsize
= skb_headlen(skb
) - offset
;
2520 if (hsize
> len
|| !sg
)
2523 if (!hsize
&& i
>= nfrags
) {
2524 BUG_ON(fskb
->len
!= len
);
2527 nskb
= skb_clone(fskb
, GFP_ATOMIC
);
2530 if (unlikely(!nskb
))
2533 hsize
= skb_end_pointer(nskb
) - nskb
->head
;
2534 if (skb_cow_head(nskb
, doffset
+ headroom
)) {
2539 nskb
->truesize
+= skb_end_pointer(nskb
) - nskb
->head
-
2541 skb_release_head_state(nskb
);
2542 __skb_push(nskb
, doffset
);
2544 nskb
= alloc_skb(hsize
+ doffset
+ headroom
,
2547 if (unlikely(!nskb
))
2550 skb_reserve(nskb
, headroom
);
2551 __skb_put(nskb
, doffset
);
2560 __copy_skb_header(nskb
, skb
);
2561 nskb
->mac_len
= skb
->mac_len
;
2563 skb_reset_mac_header(nskb
);
2564 skb_set_network_header(nskb
, skb
->mac_len
);
2565 nskb
->transport_header
= (nskb
->network_header
+
2566 skb_network_header_len(skb
));
2567 skb_copy_from_linear_data(skb
, nskb
->data
, doffset
);
2569 if (pos
>= offset
+ len
)
2573 nskb
->ip_summed
= CHECKSUM_NONE
;
2574 nskb
->csum
= skb_copy_and_csum_bits(skb
, offset
,
2580 frag
= skb_shinfo(nskb
)->frags
;
2582 skb_copy_from_linear_data_offset(skb
, offset
,
2583 skb_put(nskb
, hsize
), hsize
);
2585 while (pos
< offset
+ len
&& i
< nfrags
) {
2586 *frag
= skb_shinfo(skb
)->frags
[i
];
2587 get_page(frag
->page
);
2591 frag
->page_offset
+= offset
- pos
;
2592 frag
->size
-= offset
- pos
;
2595 skb_shinfo(nskb
)->nr_frags
++;
2597 if (pos
+ size
<= offset
+ len
) {
2601 frag
->size
-= pos
+ size
- (offset
+ len
);
2608 if (pos
< offset
+ len
) {
2609 struct sk_buff
*fskb2
= fskb
;
2611 BUG_ON(pos
+ fskb
->len
!= offset
+ len
);
2617 fskb2
= skb_clone(fskb2
, GFP_ATOMIC
);
2623 BUG_ON(skb_shinfo(nskb
)->frag_list
);
2624 skb_shinfo(nskb
)->frag_list
= fskb2
;
2628 nskb
->data_len
= len
- hsize
;
2629 nskb
->len
+= nskb
->data_len
;
2630 nskb
->truesize
+= nskb
->data_len
;
2631 } while ((offset
+= len
) < skb
->len
);
2636 while ((skb
= segs
)) {
2640 return ERR_PTR(err
);
2642 EXPORT_SYMBOL_GPL(skb_segment
);
2644 int skb_gro_receive(struct sk_buff
**head
, struct sk_buff
*skb
)
2646 struct sk_buff
*p
= *head
;
2647 struct sk_buff
*nskb
;
2648 unsigned int headroom
;
2649 unsigned int len
= skb_gro_len(skb
);
2651 if (p
->len
+ len
>= 65536)
2654 if (skb_shinfo(p
)->frag_list
)
2656 else if (skb_headlen(skb
) <= skb_gro_offset(skb
)) {
2657 if (skb_shinfo(p
)->nr_frags
+ skb_shinfo(skb
)->nr_frags
>
2661 skb_shinfo(skb
)->frags
[0].page_offset
+=
2662 skb_gro_offset(skb
) - skb_headlen(skb
);
2663 skb_shinfo(skb
)->frags
[0].size
-=
2664 skb_gro_offset(skb
) - skb_headlen(skb
);
2666 memcpy(skb_shinfo(p
)->frags
+ skb_shinfo(p
)->nr_frags
,
2667 skb_shinfo(skb
)->frags
,
2668 skb_shinfo(skb
)->nr_frags
* sizeof(skb_frag_t
));
2670 skb_shinfo(p
)->nr_frags
+= skb_shinfo(skb
)->nr_frags
;
2671 skb_shinfo(skb
)->nr_frags
= 0;
2673 skb
->truesize
-= skb
->data_len
;
2674 skb
->len
-= skb
->data_len
;
2677 NAPI_GRO_CB(skb
)->free
= 1;
2681 headroom
= skb_headroom(p
);
2682 nskb
= netdev_alloc_skb(p
->dev
, headroom
+ skb_gro_offset(p
));
2683 if (unlikely(!nskb
))
2686 __copy_skb_header(nskb
, p
);
2687 nskb
->mac_len
= p
->mac_len
;
2689 skb_reserve(nskb
, headroom
);
2690 __skb_put(nskb
, skb_gro_offset(p
));
2692 skb_set_mac_header(nskb
, skb_mac_header(p
) - p
->data
);
2693 skb_set_network_header(nskb
, skb_network_offset(p
));
2694 skb_set_transport_header(nskb
, skb_transport_offset(p
));
2696 __skb_pull(p
, skb_gro_offset(p
));
2697 memcpy(skb_mac_header(nskb
), skb_mac_header(p
),
2698 p
->data
- skb_mac_header(p
));
2700 *NAPI_GRO_CB(nskb
) = *NAPI_GRO_CB(p
);
2701 skb_shinfo(nskb
)->frag_list
= p
;
2702 skb_shinfo(nskb
)->gso_size
= skb_shinfo(p
)->gso_size
;
2703 skb_header_release(p
);
2706 nskb
->data_len
+= p
->len
;
2707 nskb
->truesize
+= p
->len
;
2708 nskb
->len
+= p
->len
;
2711 nskb
->next
= p
->next
;
2717 if (skb_gro_offset(skb
) > skb_headlen(skb
)) {
2718 skb_shinfo(skb
)->frags
[0].page_offset
+=
2719 skb_gro_offset(skb
) - skb_headlen(skb
);
2720 skb_shinfo(skb
)->frags
[0].size
-=
2721 skb_gro_offset(skb
) - skb_headlen(skb
);
2722 skb_gro_reset_offset(skb
);
2723 skb_gro_pull(skb
, skb_headlen(skb
));
2726 __skb_pull(skb
, skb_gro_offset(skb
));
2728 p
->prev
->next
= skb
;
2730 skb_header_release(skb
);
2733 NAPI_GRO_CB(p
)->count
++;
2738 NAPI_GRO_CB(skb
)->same_flow
= 1;
2741 EXPORT_SYMBOL_GPL(skb_gro_receive
);
2743 void __init
skb_init(void)
2745 skbuff_head_cache
= kmem_cache_create("skbuff_head_cache",
2746 sizeof(struct sk_buff
),
2748 SLAB_HWCACHE_ALIGN
|SLAB_PANIC
,
2750 skbuff_fclone_cache
= kmem_cache_create("skbuff_fclone_cache",
2751 (2*sizeof(struct sk_buff
)) +
2754 SLAB_HWCACHE_ALIGN
|SLAB_PANIC
,
2759 * skb_to_sgvec - Fill a scatter-gather list from a socket buffer
2760 * @skb: Socket buffer containing the buffers to be mapped
2761 * @sg: The scatter-gather list to map into
2762 * @offset: The offset into the buffer's contents to start mapping
2763 * @len: Length of buffer space to be mapped
2765 * Fill the specified scatter-gather list with mappings/pointers into a
2766 * region of the buffer space attached to a socket buffer.
2769 __skb_to_sgvec(struct sk_buff
*skb
, struct scatterlist
*sg
, int offset
, int len
)
2771 int start
= skb_headlen(skb
);
2772 int i
, copy
= start
- offset
;
2778 sg_set_buf(sg
, skb
->data
+ offset
, copy
);
2780 if ((len
-= copy
) == 0)
2785 for (i
= 0; i
< skb_shinfo(skb
)->nr_frags
; i
++) {
2788 WARN_ON(start
> offset
+ len
);
2790 end
= start
+ skb_shinfo(skb
)->frags
[i
].size
;
2791 if ((copy
= end
- offset
) > 0) {
2792 skb_frag_t
*frag
= &skb_shinfo(skb
)->frags
[i
];
2796 sg_set_page(&sg
[elt
], frag
->page
, copy
,
2797 frag
->page_offset
+offset
-start
);
2806 if (skb_shinfo(skb
)->frag_list
) {
2807 struct sk_buff
*list
= skb_shinfo(skb
)->frag_list
;
2809 for (; list
; list
= list
->next
) {
2812 WARN_ON(start
> offset
+ len
);
2814 end
= start
+ list
->len
;
2815 if ((copy
= end
- offset
) > 0) {
2818 elt
+= __skb_to_sgvec(list
, sg
+elt
, offset
- start
,
2820 if ((len
-= copy
) == 0)
2831 int skb_to_sgvec(struct sk_buff
*skb
, struct scatterlist
*sg
, int offset
, int len
)
2833 int nsg
= __skb_to_sgvec(skb
, sg
, offset
, len
);
2835 sg_mark_end(&sg
[nsg
- 1]);
2839 EXPORT_SYMBOL_GPL(skb_to_sgvec
);
2842 * skb_cow_data - Check that a socket buffer's data buffers are writable
2843 * @skb: The socket buffer to check.
2844 * @tailbits: Amount of trailing space to be added
2845 * @trailer: Returned pointer to the skb where the @tailbits space begins
2847 * Make sure that the data buffers attached to a socket buffer are
2848 * writable. If they are not, private copies are made of the data buffers
2849 * and the socket buffer is set to use these instead.
2851 * If @tailbits is given, make sure that there is space to write @tailbits
2852 * bytes of data beyond current end of socket buffer. @trailer will be
2853 * set to point to the skb in which this space begins.
2855 * The number of scatterlist elements required to completely map the
2856 * COW'd and extended socket buffer will be returned.
2858 int skb_cow_data(struct sk_buff
*skb
, int tailbits
, struct sk_buff
**trailer
)
2862 struct sk_buff
*skb1
, **skb_p
;
2864 /* If skb is cloned or its head is paged, reallocate
2865 * head pulling out all the pages (pages are considered not writable
2866 * at the moment even if they are anonymous).
2868 if ((skb_cloned(skb
) || skb_shinfo(skb
)->nr_frags
) &&
2869 __pskb_pull_tail(skb
, skb_pagelen(skb
)-skb_headlen(skb
)) == NULL
)
2872 /* Easy case. Most of packets will go this way. */
2873 if (!skb_shinfo(skb
)->frag_list
) {
2874 /* A little of trouble, not enough of space for trailer.
2875 * This should not happen, when stack is tuned to generate
2876 * good frames. OK, on miss we reallocate and reserve even more
2877 * space, 128 bytes is fair. */
2879 if (skb_tailroom(skb
) < tailbits
&&
2880 pskb_expand_head(skb
, 0, tailbits
-skb_tailroom(skb
)+128, GFP_ATOMIC
))
2888 /* Misery. We are in troubles, going to mincer fragments... */
2891 skb_p
= &skb_shinfo(skb
)->frag_list
;
2894 while ((skb1
= *skb_p
) != NULL
) {
2897 /* The fragment is partially pulled by someone,
2898 * this can happen on input. Copy it and everything
2901 if (skb_shared(skb1
))
2904 /* If the skb is the last, worry about trailer. */
2906 if (skb1
->next
== NULL
&& tailbits
) {
2907 if (skb_shinfo(skb1
)->nr_frags
||
2908 skb_shinfo(skb1
)->frag_list
||
2909 skb_tailroom(skb1
) < tailbits
)
2910 ntail
= tailbits
+ 128;
2916 skb_shinfo(skb1
)->nr_frags
||
2917 skb_shinfo(skb1
)->frag_list
) {
2918 struct sk_buff
*skb2
;
2920 /* Fuck, we are miserable poor guys... */
2922 skb2
= skb_copy(skb1
, GFP_ATOMIC
);
2924 skb2
= skb_copy_expand(skb1
,
2928 if (unlikely(skb2
== NULL
))
2932 skb_set_owner_w(skb2
, skb1
->sk
);
2934 /* Looking around. Are we still alive?
2935 * OK, link new skb, drop old one */
2937 skb2
->next
= skb1
->next
;
2944 skb_p
= &skb1
->next
;
2949 EXPORT_SYMBOL_GPL(skb_cow_data
);
2951 void skb_tstamp_tx(struct sk_buff
*orig_skb
,
2952 struct skb_shared_hwtstamps
*hwtstamps
)
2954 struct sock
*sk
= orig_skb
->sk
;
2955 struct sock_exterr_skb
*serr
;
2956 struct sk_buff
*skb
;
2962 skb
= skb_clone(orig_skb
, GFP_ATOMIC
);
2967 *skb_hwtstamps(skb
) =
2971 * no hardware time stamps available,
2972 * so keep the skb_shared_tx and only
2973 * store software time stamp
2975 skb
->tstamp
= ktime_get_real();
2978 serr
= SKB_EXT_ERR(skb
);
2979 memset(serr
, 0, sizeof(*serr
));
2980 serr
->ee
.ee_errno
= ENOMSG
;
2981 serr
->ee
.ee_origin
= SO_EE_ORIGIN_TIMESTAMPING
;
2982 err
= sock_queue_err_skb(sk
, skb
);
2986 EXPORT_SYMBOL_GPL(skb_tstamp_tx
);
2990 * skb_partial_csum_set - set up and verify partial csum values for packet
2991 * @skb: the skb to set
2992 * @start: the number of bytes after skb->data to start checksumming.
2993 * @off: the offset from start to place the checksum.
2995 * For untrusted partially-checksummed packets, we need to make sure the values
2996 * for skb->csum_start and skb->csum_offset are valid so we don't oops.
2998 * This function checks and sets those values and skb->ip_summed: if this
2999 * returns false you should drop the packet.
3001 bool skb_partial_csum_set(struct sk_buff
*skb
, u16 start
, u16 off
)
3003 if (unlikely(start
> skb
->len
- 2) ||
3004 unlikely((int)start
+ off
> skb
->len
- 2)) {
3005 if (net_ratelimit())
3007 "bad partial csum: csum=%u/%u len=%u\n",
3008 start
, off
, skb
->len
);
3011 skb
->ip_summed
= CHECKSUM_PARTIAL
;
3012 skb
->csum_start
= skb_headroom(skb
) + start
;
3013 skb
->csum_offset
= off
;
3016 EXPORT_SYMBOL_GPL(skb_partial_csum_set
);
3018 void __skb_warn_lro_forwarding(const struct sk_buff
*skb
)
3020 if (net_ratelimit())
3021 pr_warning("%s: received packets cannot be forwarded"
3022 " while LRO is enabled\n", skb
->dev
->name
);
3024 EXPORT_SYMBOL(__skb_warn_lro_forwarding
);