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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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/tcp.h>
50 #include <linux/udp.h>
51 #include <linux/sctp.h>
52 #include <linux/netdevice.h>
53 #ifdef CONFIG_NET_CLS_ACT
54 #include <net/pkt_sched.h>
56 #include <linux/string.h>
57 #include <linux/skbuff.h>
58 #include <linux/splice.h>
59 #include <linux/cache.h>
60 #include <linux/rtnetlink.h>
61 #include <linux/init.h>
62 #include <linux/scatterlist.h>
63 #include <linux/errqueue.h>
64 #include <linux/prefetch.h>
65 #include <linux/if_vlan.h>
67 #include <net/protocol.h>
70 #include <net/checksum.h>
71 #include <net/ip6_checksum.h>
74 #include <linux/uaccess.h>
75 #include <trace/events/skb.h>
76 #include <linux/highmem.h>
77 #include <linux/capability.h>
78 #include <linux/user_namespace.h>
80 struct kmem_cache
*skbuff_head_cache __ro_after_init
;
81 static struct kmem_cache
*skbuff_fclone_cache __ro_after_init
;
82 #ifdef CONFIG_SKB_EXTENSIONS
83 static struct kmem_cache
*skbuff_ext_cache __ro_after_init
;
85 int sysctl_max_skb_frags __read_mostly
= MAX_SKB_FRAGS
;
86 EXPORT_SYMBOL(sysctl_max_skb_frags
);
89 * skb_panic - private function for out-of-line support
93 * @msg: skb_over_panic or skb_under_panic
95 * Out-of-line support for skb_put() and skb_push().
96 * Called via the wrapper skb_over_panic() or skb_under_panic().
97 * Keep out of line to prevent kernel bloat.
98 * __builtin_return_address is not used because it is not always reliable.
100 static void skb_panic(struct sk_buff
*skb
, unsigned int sz
, void *addr
,
103 pr_emerg("%s: text:%p len:%d put:%d head:%p data:%p tail:%#lx end:%#lx dev:%s\n",
104 msg
, addr
, skb
->len
, sz
, skb
->head
, skb
->data
,
105 (unsigned long)skb
->tail
, (unsigned long)skb
->end
,
106 skb
->dev
? skb
->dev
->name
: "<NULL>");
110 static void skb_over_panic(struct sk_buff
*skb
, unsigned int sz
, void *addr
)
112 skb_panic(skb
, sz
, addr
, __func__
);
115 static void skb_under_panic(struct sk_buff
*skb
, unsigned int sz
, void *addr
)
117 skb_panic(skb
, sz
, addr
, __func__
);
121 * kmalloc_reserve is a wrapper around kmalloc_node_track_caller that tells
122 * the caller if emergency pfmemalloc reserves are being used. If it is and
123 * the socket is later found to be SOCK_MEMALLOC then PFMEMALLOC reserves
124 * may be used. Otherwise, the packet data may be discarded until enough
127 #define kmalloc_reserve(size, gfp, node, pfmemalloc) \
128 __kmalloc_reserve(size, gfp, node, _RET_IP_, pfmemalloc)
130 static void *__kmalloc_reserve(size_t size
, gfp_t flags
, int node
,
131 unsigned long ip
, bool *pfmemalloc
)
134 bool ret_pfmemalloc
= false;
137 * Try a regular allocation, when that fails and we're not entitled
138 * to the reserves, fail.
140 obj
= kmalloc_node_track_caller(size
,
141 flags
| __GFP_NOMEMALLOC
| __GFP_NOWARN
,
143 if (obj
|| !(gfp_pfmemalloc_allowed(flags
)))
146 /* Try again but now we are using pfmemalloc reserves */
147 ret_pfmemalloc
= true;
148 obj
= kmalloc_node_track_caller(size
, flags
, node
);
152 *pfmemalloc
= ret_pfmemalloc
;
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 * @flags: If SKB_ALLOC_FCLONE is set, allocate from fclone cache
168 * instead of head cache and allocate a cloned (child) skb.
169 * If SKB_ALLOC_RX is set, __GFP_MEMALLOC will be used for
170 * allocations in case the data is required for writeback
171 * @node: numa node to allocate memory on
173 * Allocate a new &sk_buff. The returned buffer has no headroom and a
174 * tail room of at least size bytes. The object has a reference count
175 * of one. The return is the buffer. On a failure the return is %NULL.
177 * Buffers may only be allocated from interrupts using a @gfp_mask of
180 struct sk_buff
*__alloc_skb(unsigned int size
, gfp_t gfp_mask
,
183 struct kmem_cache
*cache
;
184 struct skb_shared_info
*shinfo
;
189 cache
= (flags
& SKB_ALLOC_FCLONE
)
190 ? skbuff_fclone_cache
: skbuff_head_cache
;
192 if (sk_memalloc_socks() && (flags
& SKB_ALLOC_RX
))
193 gfp_mask
|= __GFP_MEMALLOC
;
196 skb
= kmem_cache_alloc_node(cache
, gfp_mask
& ~__GFP_DMA
, node
);
201 /* We do our best to align skb_shared_info on a separate cache
202 * line. It usually works because kmalloc(X > SMP_CACHE_BYTES) gives
203 * aligned memory blocks, unless SLUB/SLAB debug is enabled.
204 * Both skb->head and skb_shared_info are cache line aligned.
206 size
= SKB_DATA_ALIGN(size
);
207 size
+= SKB_DATA_ALIGN(sizeof(struct skb_shared_info
));
208 data
= kmalloc_reserve(size
, gfp_mask
, node
, &pfmemalloc
);
211 /* kmalloc(size) might give us more room than requested.
212 * Put skb_shared_info exactly at the end of allocated zone,
213 * to allow max possible filling before reallocation.
215 size
= SKB_WITH_OVERHEAD(ksize(data
));
216 prefetchw(data
+ size
);
219 * Only clear those fields we need to clear, not those that we will
220 * actually initialise below. Hence, don't put any more fields after
221 * the tail pointer in struct sk_buff!
223 memset(skb
, 0, offsetof(struct sk_buff
, tail
));
224 /* Account for allocated memory : skb + skb->head */
225 skb
->truesize
= SKB_TRUESIZE(size
);
226 skb
->pfmemalloc
= pfmemalloc
;
227 refcount_set(&skb
->users
, 1);
230 skb_reset_tail_pointer(skb
);
231 skb
->end
= skb
->tail
+ size
;
232 skb
->mac_header
= (typeof(skb
->mac_header
))~0U;
233 skb
->transport_header
= (typeof(skb
->transport_header
))~0U;
235 /* make sure we initialize shinfo sequentially */
236 shinfo
= skb_shinfo(skb
);
237 memset(shinfo
, 0, offsetof(struct skb_shared_info
, dataref
));
238 atomic_set(&shinfo
->dataref
, 1);
240 if (flags
& SKB_ALLOC_FCLONE
) {
241 struct sk_buff_fclones
*fclones
;
243 fclones
= container_of(skb
, struct sk_buff_fclones
, skb1
);
245 skb
->fclone
= SKB_FCLONE_ORIG
;
246 refcount_set(&fclones
->fclone_ref
, 1);
248 fclones
->skb2
.fclone
= SKB_FCLONE_CLONE
;
253 kmem_cache_free(cache
, skb
);
257 EXPORT_SYMBOL(__alloc_skb
);
260 * __build_skb - build a network buffer
261 * @data: data buffer provided by caller
262 * @frag_size: size of data, or 0 if head was kmalloced
264 * Allocate a new &sk_buff. Caller provides space holding head and
265 * skb_shared_info. @data must have been allocated by kmalloc() only if
266 * @frag_size is 0, otherwise data should come from the page allocator
268 * The return is the new skb buffer.
269 * On a failure the return is %NULL, and @data is not freed.
271 * Before IO, driver allocates only data buffer where NIC put incoming frame
272 * Driver should add room at head (NET_SKB_PAD) and
273 * MUST add room at tail (SKB_DATA_ALIGN(skb_shared_info))
274 * After IO, driver calls build_skb(), to allocate sk_buff and populate it
275 * before giving packet to stack.
276 * RX rings only contains data buffers, not full skbs.
278 struct sk_buff
*__build_skb(void *data
, unsigned int frag_size
)
280 struct skb_shared_info
*shinfo
;
282 unsigned int size
= frag_size
? : ksize(data
);
284 skb
= kmem_cache_alloc(skbuff_head_cache
, GFP_ATOMIC
);
288 size
-= SKB_DATA_ALIGN(sizeof(struct skb_shared_info
));
290 memset(skb
, 0, offsetof(struct sk_buff
, tail
));
291 skb
->truesize
= SKB_TRUESIZE(size
);
292 refcount_set(&skb
->users
, 1);
295 skb_reset_tail_pointer(skb
);
296 skb
->end
= skb
->tail
+ size
;
297 skb
->mac_header
= (typeof(skb
->mac_header
))~0U;
298 skb
->transport_header
= (typeof(skb
->transport_header
))~0U;
300 /* make sure we initialize shinfo sequentially */
301 shinfo
= skb_shinfo(skb
);
302 memset(shinfo
, 0, offsetof(struct skb_shared_info
, dataref
));
303 atomic_set(&shinfo
->dataref
, 1);
308 /* build_skb() is wrapper over __build_skb(), that specifically
309 * takes care of skb->head and skb->pfmemalloc
310 * This means that if @frag_size is not zero, then @data must be backed
311 * by a page fragment, not kmalloc() or vmalloc()
313 struct sk_buff
*build_skb(void *data
, unsigned int frag_size
)
315 struct sk_buff
*skb
= __build_skb(data
, frag_size
);
317 if (skb
&& frag_size
) {
319 if (page_is_pfmemalloc(virt_to_head_page(data
)))
324 EXPORT_SYMBOL(build_skb
);
326 #define NAPI_SKB_CACHE_SIZE 64
328 struct napi_alloc_cache
{
329 struct page_frag_cache page
;
330 unsigned int skb_count
;
331 void *skb_cache
[NAPI_SKB_CACHE_SIZE
];
334 static DEFINE_PER_CPU(struct page_frag_cache
, netdev_alloc_cache
);
335 static DEFINE_PER_CPU(struct napi_alloc_cache
, napi_alloc_cache
);
337 static void *__netdev_alloc_frag(unsigned int fragsz
, gfp_t gfp_mask
)
339 struct page_frag_cache
*nc
;
343 local_irq_save(flags
);
344 nc
= this_cpu_ptr(&netdev_alloc_cache
);
345 data
= page_frag_alloc(nc
, fragsz
, gfp_mask
);
346 local_irq_restore(flags
);
351 * netdev_alloc_frag - allocate a page fragment
352 * @fragsz: fragment size
354 * Allocates a frag from a page for receive buffer.
355 * Uses GFP_ATOMIC allocations.
357 void *netdev_alloc_frag(unsigned int fragsz
)
359 fragsz
= SKB_DATA_ALIGN(fragsz
);
361 return __netdev_alloc_frag(fragsz
, GFP_ATOMIC
);
363 EXPORT_SYMBOL(netdev_alloc_frag
);
365 static void *__napi_alloc_frag(unsigned int fragsz
, gfp_t gfp_mask
)
367 struct napi_alloc_cache
*nc
= this_cpu_ptr(&napi_alloc_cache
);
369 return page_frag_alloc(&nc
->page
, fragsz
, gfp_mask
);
372 void *napi_alloc_frag(unsigned int fragsz
)
374 fragsz
= SKB_DATA_ALIGN(fragsz
);
376 return __napi_alloc_frag(fragsz
, GFP_ATOMIC
);
378 EXPORT_SYMBOL(napi_alloc_frag
);
381 * __netdev_alloc_skb - allocate an skbuff for rx on a specific device
382 * @dev: network device to receive on
383 * @len: length to allocate
384 * @gfp_mask: get_free_pages mask, passed to alloc_skb
386 * Allocate a new &sk_buff and assign it a usage count of one. The
387 * buffer has NET_SKB_PAD headroom built in. Users should allocate
388 * the headroom they think they need without accounting for the
389 * built in space. The built in space is used for optimisations.
391 * %NULL is returned if there is no free memory.
393 struct sk_buff
*__netdev_alloc_skb(struct net_device
*dev
, unsigned int len
,
396 struct page_frag_cache
*nc
;
404 if ((len
> SKB_WITH_OVERHEAD(PAGE_SIZE
)) ||
405 (gfp_mask
& (__GFP_DIRECT_RECLAIM
| GFP_DMA
))) {
406 skb
= __alloc_skb(len
, gfp_mask
, SKB_ALLOC_RX
, NUMA_NO_NODE
);
412 len
+= SKB_DATA_ALIGN(sizeof(struct skb_shared_info
));
413 len
= SKB_DATA_ALIGN(len
);
415 if (sk_memalloc_socks())
416 gfp_mask
|= __GFP_MEMALLOC
;
418 local_irq_save(flags
);
420 nc
= this_cpu_ptr(&netdev_alloc_cache
);
421 data
= page_frag_alloc(nc
, len
, gfp_mask
);
422 pfmemalloc
= nc
->pfmemalloc
;
424 local_irq_restore(flags
);
429 skb
= __build_skb(data
, len
);
430 if (unlikely(!skb
)) {
435 /* use OR instead of assignment to avoid clearing of bits in mask */
441 skb_reserve(skb
, NET_SKB_PAD
);
447 EXPORT_SYMBOL(__netdev_alloc_skb
);
450 * __napi_alloc_skb - allocate skbuff for rx in a specific NAPI instance
451 * @napi: napi instance this buffer was allocated for
452 * @len: length to allocate
453 * @gfp_mask: get_free_pages mask, passed to alloc_skb and alloc_pages
455 * Allocate a new sk_buff for use in NAPI receive. This buffer will
456 * attempt to allocate the head from a special reserved region used
457 * only for NAPI Rx allocation. By doing this we can save several
458 * CPU cycles by avoiding having to disable and re-enable IRQs.
460 * %NULL is returned if there is no free memory.
462 struct sk_buff
*__napi_alloc_skb(struct napi_struct
*napi
, unsigned int len
,
465 struct napi_alloc_cache
*nc
= this_cpu_ptr(&napi_alloc_cache
);
469 len
+= NET_SKB_PAD
+ NET_IP_ALIGN
;
471 if ((len
> SKB_WITH_OVERHEAD(PAGE_SIZE
)) ||
472 (gfp_mask
& (__GFP_DIRECT_RECLAIM
| GFP_DMA
))) {
473 skb
= __alloc_skb(len
, gfp_mask
, SKB_ALLOC_RX
, NUMA_NO_NODE
);
479 len
+= SKB_DATA_ALIGN(sizeof(struct skb_shared_info
));
480 len
= SKB_DATA_ALIGN(len
);
482 if (sk_memalloc_socks())
483 gfp_mask
|= __GFP_MEMALLOC
;
485 data
= page_frag_alloc(&nc
->page
, len
, gfp_mask
);
489 skb
= __build_skb(data
, len
);
490 if (unlikely(!skb
)) {
495 /* use OR instead of assignment to avoid clearing of bits in mask */
496 if (nc
->page
.pfmemalloc
)
501 skb_reserve(skb
, NET_SKB_PAD
+ NET_IP_ALIGN
);
502 skb
->dev
= napi
->dev
;
507 EXPORT_SYMBOL(__napi_alloc_skb
);
509 void skb_add_rx_frag(struct sk_buff
*skb
, int i
, struct page
*page
, int off
,
510 int size
, unsigned int truesize
)
512 skb_fill_page_desc(skb
, i
, page
, off
, size
);
514 skb
->data_len
+= size
;
515 skb
->truesize
+= truesize
;
517 EXPORT_SYMBOL(skb_add_rx_frag
);
519 void skb_coalesce_rx_frag(struct sk_buff
*skb
, int i
, int size
,
520 unsigned int truesize
)
522 skb_frag_t
*frag
= &skb_shinfo(skb
)->frags
[i
];
524 skb_frag_size_add(frag
, size
);
526 skb
->data_len
+= size
;
527 skb
->truesize
+= truesize
;
529 EXPORT_SYMBOL(skb_coalesce_rx_frag
);
531 static void skb_drop_list(struct sk_buff
**listp
)
533 kfree_skb_list(*listp
);
537 static inline void skb_drop_fraglist(struct sk_buff
*skb
)
539 skb_drop_list(&skb_shinfo(skb
)->frag_list
);
542 static void skb_clone_fraglist(struct sk_buff
*skb
)
544 struct sk_buff
*list
;
546 skb_walk_frags(skb
, list
)
550 static void skb_free_head(struct sk_buff
*skb
)
552 unsigned char *head
= skb
->head
;
560 static void skb_release_data(struct sk_buff
*skb
)
562 struct skb_shared_info
*shinfo
= skb_shinfo(skb
);
566 atomic_sub_return(skb
->nohdr
? (1 << SKB_DATAREF_SHIFT
) + 1 : 1,
570 for (i
= 0; i
< shinfo
->nr_frags
; i
++)
571 __skb_frag_unref(&shinfo
->frags
[i
]);
573 if (shinfo
->frag_list
)
574 kfree_skb_list(shinfo
->frag_list
);
576 skb_zcopy_clear(skb
, true);
581 * Free an skbuff by memory without cleaning the state.
583 static void kfree_skbmem(struct sk_buff
*skb
)
585 struct sk_buff_fclones
*fclones
;
587 switch (skb
->fclone
) {
588 case SKB_FCLONE_UNAVAILABLE
:
589 kmem_cache_free(skbuff_head_cache
, skb
);
592 case SKB_FCLONE_ORIG
:
593 fclones
= container_of(skb
, struct sk_buff_fclones
, skb1
);
595 /* We usually free the clone (TX completion) before original skb
596 * This test would have no chance to be true for the clone,
597 * while here, branch prediction will be good.
599 if (refcount_read(&fclones
->fclone_ref
) == 1)
603 default: /* SKB_FCLONE_CLONE */
604 fclones
= container_of(skb
, struct sk_buff_fclones
, skb2
);
607 if (!refcount_dec_and_test(&fclones
->fclone_ref
))
610 kmem_cache_free(skbuff_fclone_cache
, fclones
);
613 void skb_release_head_state(struct sk_buff
*skb
)
616 if (skb
->destructor
) {
618 skb
->destructor(skb
);
620 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
621 nf_conntrack_put(skb_nfct(skb
));
626 /* Free everything but the sk_buff shell. */
627 static void skb_release_all(struct sk_buff
*skb
)
629 skb_release_head_state(skb
);
630 if (likely(skb
->head
))
631 skb_release_data(skb
);
635 * __kfree_skb - private function
638 * Free an sk_buff. Release anything attached to the buffer.
639 * Clean the state. This is an internal helper function. Users should
640 * always call kfree_skb
643 void __kfree_skb(struct sk_buff
*skb
)
645 skb_release_all(skb
);
648 EXPORT_SYMBOL(__kfree_skb
);
651 * kfree_skb - free an sk_buff
652 * @skb: buffer to free
654 * Drop a reference to the buffer and free it if the usage count has
657 void kfree_skb(struct sk_buff
*skb
)
662 trace_kfree_skb(skb
, __builtin_return_address(0));
665 EXPORT_SYMBOL(kfree_skb
);
667 void kfree_skb_list(struct sk_buff
*segs
)
670 struct sk_buff
*next
= segs
->next
;
676 EXPORT_SYMBOL(kfree_skb_list
);
679 * skb_tx_error - report an sk_buff xmit error
680 * @skb: buffer that triggered an error
682 * Report xmit error if a device callback is tracking this skb.
683 * skb must be freed afterwards.
685 void skb_tx_error(struct sk_buff
*skb
)
687 skb_zcopy_clear(skb
, true);
689 EXPORT_SYMBOL(skb_tx_error
);
692 * consume_skb - free an skbuff
693 * @skb: buffer to free
695 * Drop a ref to the buffer and free it if the usage count has hit zero
696 * Functions identically to kfree_skb, but kfree_skb assumes that the frame
697 * is being dropped after a failure and notes that
699 void consume_skb(struct sk_buff
*skb
)
704 trace_consume_skb(skb
);
707 EXPORT_SYMBOL(consume_skb
);
710 * consume_stateless_skb - free an skbuff, assuming it is stateless
711 * @skb: buffer to free
713 * Alike consume_skb(), but this variant assumes that this is the last
714 * skb reference and all the head states have been already dropped
716 void __consume_stateless_skb(struct sk_buff
*skb
)
718 trace_consume_skb(skb
);
719 skb_release_data(skb
);
723 void __kfree_skb_flush(void)
725 struct napi_alloc_cache
*nc
= this_cpu_ptr(&napi_alloc_cache
);
727 /* flush skb_cache if containing objects */
729 kmem_cache_free_bulk(skbuff_head_cache
, nc
->skb_count
,
735 static inline void _kfree_skb_defer(struct sk_buff
*skb
)
737 struct napi_alloc_cache
*nc
= this_cpu_ptr(&napi_alloc_cache
);
739 /* drop skb->head and call any destructors for packet */
740 skb_release_all(skb
);
742 /* record skb to CPU local list */
743 nc
->skb_cache
[nc
->skb_count
++] = skb
;
746 /* SLUB writes into objects when freeing */
750 /* flush skb_cache if it is filled */
751 if (unlikely(nc
->skb_count
== NAPI_SKB_CACHE_SIZE
)) {
752 kmem_cache_free_bulk(skbuff_head_cache
, NAPI_SKB_CACHE_SIZE
,
757 void __kfree_skb_defer(struct sk_buff
*skb
)
759 _kfree_skb_defer(skb
);
762 void napi_consume_skb(struct sk_buff
*skb
, int budget
)
767 /* Zero budget indicate non-NAPI context called us, like netpoll */
768 if (unlikely(!budget
)) {
769 dev_consume_skb_any(skb
);
776 /* if reaching here SKB is ready to free */
777 trace_consume_skb(skb
);
779 /* if SKB is a clone, don't handle this case */
780 if (skb
->fclone
!= SKB_FCLONE_UNAVAILABLE
) {
785 _kfree_skb_defer(skb
);
787 EXPORT_SYMBOL(napi_consume_skb
);
789 /* Make sure a field is enclosed inside headers_start/headers_end section */
790 #define CHECK_SKB_FIELD(field) \
791 BUILD_BUG_ON(offsetof(struct sk_buff, field) < \
792 offsetof(struct sk_buff, headers_start)); \
793 BUILD_BUG_ON(offsetof(struct sk_buff, field) > \
794 offsetof(struct sk_buff, headers_end)); \
796 static void __copy_skb_header(struct sk_buff *new, const struct sk_buff *old)
798 new->tstamp
= old
->tstamp
;
799 /* We do not copy old->sk */
801 memcpy(new->cb
, old
->cb
, sizeof(old
->cb
));
802 skb_dst_copy(new, old
);
803 __skb_ext_copy(new, old
);
804 __nf_copy(new, old
, false);
806 /* Note : this field could be in headers_start/headers_end section
807 * It is not yet because we do not want to have a 16 bit hole
809 new->queue_mapping
= old
->queue_mapping
;
811 memcpy(&new->headers_start
, &old
->headers_start
,
812 offsetof(struct sk_buff
, headers_end
) -
813 offsetof(struct sk_buff
, headers_start
));
814 CHECK_SKB_FIELD(protocol
);
815 CHECK_SKB_FIELD(csum
);
816 CHECK_SKB_FIELD(hash
);
817 CHECK_SKB_FIELD(priority
);
818 CHECK_SKB_FIELD(skb_iif
);
819 CHECK_SKB_FIELD(vlan_proto
);
820 CHECK_SKB_FIELD(vlan_tci
);
821 CHECK_SKB_FIELD(transport_header
);
822 CHECK_SKB_FIELD(network_header
);
823 CHECK_SKB_FIELD(mac_header
);
824 CHECK_SKB_FIELD(inner_protocol
);
825 CHECK_SKB_FIELD(inner_transport_header
);
826 CHECK_SKB_FIELD(inner_network_header
);
827 CHECK_SKB_FIELD(inner_mac_header
);
828 CHECK_SKB_FIELD(mark
);
829 #ifdef CONFIG_NETWORK_SECMARK
830 CHECK_SKB_FIELD(secmark
);
832 #ifdef CONFIG_NET_RX_BUSY_POLL
833 CHECK_SKB_FIELD(napi_id
);
836 CHECK_SKB_FIELD(sender_cpu
);
838 #ifdef CONFIG_NET_SCHED
839 CHECK_SKB_FIELD(tc_index
);
845 * You should not add any new code to this function. Add it to
846 * __copy_skb_header above instead.
848 static struct sk_buff
*__skb_clone(struct sk_buff
*n
, struct sk_buff
*skb
)
850 #define C(x) n->x = skb->x
852 n
->next
= n
->prev
= NULL
;
854 __copy_skb_header(n
, skb
);
859 n
->hdr_len
= skb
->nohdr
? skb_headroom(skb
) : skb
->hdr_len
;
864 n
->destructor
= NULL
;
871 refcount_set(&n
->users
, 1);
873 atomic_inc(&(skb_shinfo(skb
)->dataref
));
881 * skb_morph - morph one skb into another
882 * @dst: the skb to receive the contents
883 * @src: the skb to supply the contents
885 * This is identical to skb_clone except that the target skb is
886 * supplied by the user.
888 * The target skb is returned upon exit.
890 struct sk_buff
*skb_morph(struct sk_buff
*dst
, struct sk_buff
*src
)
892 skb_release_all(dst
);
893 return __skb_clone(dst
, src
);
895 EXPORT_SYMBOL_GPL(skb_morph
);
897 int mm_account_pinned_pages(struct mmpin
*mmp
, size_t size
)
899 unsigned long max_pg
, num_pg
, new_pg
, old_pg
;
900 struct user_struct
*user
;
902 if (capable(CAP_IPC_LOCK
) || !size
)
905 num_pg
= (size
>> PAGE_SHIFT
) + 2; /* worst case */
906 max_pg
= rlimit(RLIMIT_MEMLOCK
) >> PAGE_SHIFT
;
907 user
= mmp
->user
? : current_user();
910 old_pg
= atomic_long_read(&user
->locked_vm
);
911 new_pg
= old_pg
+ num_pg
;
914 } while (atomic_long_cmpxchg(&user
->locked_vm
, old_pg
, new_pg
) !=
918 mmp
->user
= get_uid(user
);
919 mmp
->num_pg
= num_pg
;
921 mmp
->num_pg
+= num_pg
;
926 EXPORT_SYMBOL_GPL(mm_account_pinned_pages
);
928 void mm_unaccount_pinned_pages(struct mmpin
*mmp
)
931 atomic_long_sub(mmp
->num_pg
, &mmp
->user
->locked_vm
);
935 EXPORT_SYMBOL_GPL(mm_unaccount_pinned_pages
);
937 struct ubuf_info
*sock_zerocopy_alloc(struct sock
*sk
, size_t size
)
939 struct ubuf_info
*uarg
;
942 WARN_ON_ONCE(!in_task());
944 skb
= sock_omalloc(sk
, 0, GFP_KERNEL
);
948 BUILD_BUG_ON(sizeof(*uarg
) > sizeof(skb
->cb
));
949 uarg
= (void *)skb
->cb
;
950 uarg
->mmp
.user
= NULL
;
952 if (mm_account_pinned_pages(&uarg
->mmp
, size
)) {
957 uarg
->callback
= sock_zerocopy_callback
;
958 uarg
->id
= ((u32
)atomic_inc_return(&sk
->sk_zckey
)) - 1;
960 uarg
->bytelen
= size
;
962 refcount_set(&uarg
->refcnt
, 1);
967 EXPORT_SYMBOL_GPL(sock_zerocopy_alloc
);
969 static inline struct sk_buff
*skb_from_uarg(struct ubuf_info
*uarg
)
971 return container_of((void *)uarg
, struct sk_buff
, cb
);
974 struct ubuf_info
*sock_zerocopy_realloc(struct sock
*sk
, size_t size
,
975 struct ubuf_info
*uarg
)
978 const u32 byte_limit
= 1 << 19; /* limit to a few TSO */
981 /* realloc only when socket is locked (TCP, UDP cork),
982 * so uarg->len and sk_zckey access is serialized
984 if (!sock_owned_by_user(sk
)) {
989 bytelen
= uarg
->bytelen
+ size
;
990 if (uarg
->len
== USHRT_MAX
- 1 || bytelen
> byte_limit
) {
991 /* TCP can create new skb to attach new uarg */
992 if (sk
->sk_type
== SOCK_STREAM
)
997 next
= (u32
)atomic_read(&sk
->sk_zckey
);
998 if ((u32
)(uarg
->id
+ uarg
->len
) == next
) {
999 if (mm_account_pinned_pages(&uarg
->mmp
, size
))
1002 uarg
->bytelen
= bytelen
;
1003 atomic_set(&sk
->sk_zckey
, ++next
);
1004 sock_zerocopy_get(uarg
);
1010 return sock_zerocopy_alloc(sk
, size
);
1012 EXPORT_SYMBOL_GPL(sock_zerocopy_realloc
);
1014 static bool skb_zerocopy_notify_extend(struct sk_buff
*skb
, u32 lo
, u16 len
)
1016 struct sock_exterr_skb
*serr
= SKB_EXT_ERR(skb
);
1020 old_lo
= serr
->ee
.ee_info
;
1021 old_hi
= serr
->ee
.ee_data
;
1022 sum_len
= old_hi
- old_lo
+ 1ULL + len
;
1024 if (sum_len
>= (1ULL << 32))
1027 if (lo
!= old_hi
+ 1)
1030 serr
->ee
.ee_data
+= len
;
1034 void sock_zerocopy_callback(struct ubuf_info
*uarg
, bool success
)
1036 struct sk_buff
*tail
, *skb
= skb_from_uarg(uarg
);
1037 struct sock_exterr_skb
*serr
;
1038 struct sock
*sk
= skb
->sk
;
1039 struct sk_buff_head
*q
;
1040 unsigned long flags
;
1044 mm_unaccount_pinned_pages(&uarg
->mmp
);
1046 /* if !len, there was only 1 call, and it was aborted
1047 * so do not queue a completion notification
1049 if (!uarg
->len
|| sock_flag(sk
, SOCK_DEAD
))
1054 hi
= uarg
->id
+ len
- 1;
1056 serr
= SKB_EXT_ERR(skb
);
1057 memset(serr
, 0, sizeof(*serr
));
1058 serr
->ee
.ee_errno
= 0;
1059 serr
->ee
.ee_origin
= SO_EE_ORIGIN_ZEROCOPY
;
1060 serr
->ee
.ee_data
= hi
;
1061 serr
->ee
.ee_info
= lo
;
1063 serr
->ee
.ee_code
|= SO_EE_CODE_ZEROCOPY_COPIED
;
1065 q
= &sk
->sk_error_queue
;
1066 spin_lock_irqsave(&q
->lock
, flags
);
1067 tail
= skb_peek_tail(q
);
1068 if (!tail
|| SKB_EXT_ERR(tail
)->ee
.ee_origin
!= SO_EE_ORIGIN_ZEROCOPY
||
1069 !skb_zerocopy_notify_extend(tail
, lo
, len
)) {
1070 __skb_queue_tail(q
, skb
);
1073 spin_unlock_irqrestore(&q
->lock
, flags
);
1075 sk
->sk_error_report(sk
);
1081 EXPORT_SYMBOL_GPL(sock_zerocopy_callback
);
1083 void sock_zerocopy_put(struct ubuf_info
*uarg
)
1085 if (uarg
&& refcount_dec_and_test(&uarg
->refcnt
)) {
1087 uarg
->callback(uarg
, uarg
->zerocopy
);
1089 consume_skb(skb_from_uarg(uarg
));
1092 EXPORT_SYMBOL_GPL(sock_zerocopy_put
);
1094 void sock_zerocopy_put_abort(struct ubuf_info
*uarg
, bool have_uref
)
1097 struct sock
*sk
= skb_from_uarg(uarg
)->sk
;
1099 atomic_dec(&sk
->sk_zckey
);
1103 sock_zerocopy_put(uarg
);
1106 EXPORT_SYMBOL_GPL(sock_zerocopy_put_abort
);
1108 extern int __zerocopy_sg_from_iter(struct sock
*sk
, struct sk_buff
*skb
,
1109 struct iov_iter
*from
, size_t length
);
1111 int skb_zerocopy_iter_dgram(struct sk_buff
*skb
, struct msghdr
*msg
, int len
)
1113 return __zerocopy_sg_from_iter(skb
->sk
, skb
, &msg
->msg_iter
, len
);
1115 EXPORT_SYMBOL_GPL(skb_zerocopy_iter_dgram
);
1117 int skb_zerocopy_iter_stream(struct sock
*sk
, struct sk_buff
*skb
,
1118 struct msghdr
*msg
, int len
,
1119 struct ubuf_info
*uarg
)
1121 struct ubuf_info
*orig_uarg
= skb_zcopy(skb
);
1122 struct iov_iter orig_iter
= msg
->msg_iter
;
1123 int err
, orig_len
= skb
->len
;
1125 /* An skb can only point to one uarg. This edge case happens when
1126 * TCP appends to an skb, but zerocopy_realloc triggered a new alloc.
1128 if (orig_uarg
&& uarg
!= orig_uarg
)
1131 err
= __zerocopy_sg_from_iter(sk
, skb
, &msg
->msg_iter
, len
);
1132 if (err
== -EFAULT
|| (err
== -EMSGSIZE
&& skb
->len
== orig_len
)) {
1133 struct sock
*save_sk
= skb
->sk
;
1135 /* Streams do not free skb on error. Reset to prev state. */
1136 msg
->msg_iter
= orig_iter
;
1138 ___pskb_trim(skb
, orig_len
);
1143 skb_zcopy_set(skb
, uarg
, NULL
);
1144 return skb
->len
- orig_len
;
1146 EXPORT_SYMBOL_GPL(skb_zerocopy_iter_stream
);
1148 static int skb_zerocopy_clone(struct sk_buff
*nskb
, struct sk_buff
*orig
,
1151 if (skb_zcopy(orig
)) {
1152 if (skb_zcopy(nskb
)) {
1153 /* !gfp_mask callers are verified to !skb_zcopy(nskb) */
1158 if (skb_uarg(nskb
) == skb_uarg(orig
))
1160 if (skb_copy_ubufs(nskb
, GFP_ATOMIC
))
1163 skb_zcopy_set(nskb
, skb_uarg(orig
), NULL
);
1169 * skb_copy_ubufs - copy userspace skb frags buffers to kernel
1170 * @skb: the skb to modify
1171 * @gfp_mask: allocation priority
1173 * This must be called on SKBTX_DEV_ZEROCOPY skb.
1174 * It will copy all frags into kernel and drop the reference
1175 * to userspace pages.
1177 * If this function is called from an interrupt gfp_mask() must be
1180 * Returns 0 on success or a negative error code on failure
1181 * to allocate kernel memory to copy to.
1183 int skb_copy_ubufs(struct sk_buff
*skb
, gfp_t gfp_mask
)
1185 int num_frags
= skb_shinfo(skb
)->nr_frags
;
1186 struct page
*page
, *head
= NULL
;
1190 if (skb_shared(skb
) || skb_unclone(skb
, gfp_mask
))
1196 new_frags
= (__skb_pagelen(skb
) + PAGE_SIZE
- 1) >> PAGE_SHIFT
;
1197 for (i
= 0; i
< new_frags
; i
++) {
1198 page
= alloc_page(gfp_mask
);
1201 struct page
*next
= (struct page
*)page_private(head
);
1207 set_page_private(page
, (unsigned long)head
);
1213 for (i
= 0; i
< num_frags
; i
++) {
1214 skb_frag_t
*f
= &skb_shinfo(skb
)->frags
[i
];
1215 u32 p_off
, p_len
, copied
;
1219 skb_frag_foreach_page(f
, f
->page_offset
, skb_frag_size(f
),
1220 p
, p_off
, p_len
, copied
) {
1222 vaddr
= kmap_atomic(p
);
1224 while (done
< p_len
) {
1225 if (d_off
== PAGE_SIZE
) {
1227 page
= (struct page
*)page_private(page
);
1229 copy
= min_t(u32
, PAGE_SIZE
- d_off
, p_len
- done
);
1230 memcpy(page_address(page
) + d_off
,
1231 vaddr
+ p_off
+ done
, copy
);
1235 kunmap_atomic(vaddr
);
1239 /* skb frags release userspace buffers */
1240 for (i
= 0; i
< num_frags
; i
++)
1241 skb_frag_unref(skb
, i
);
1243 /* skb frags point to kernel buffers */
1244 for (i
= 0; i
< new_frags
- 1; i
++) {
1245 __skb_fill_page_desc(skb
, i
, head
, 0, PAGE_SIZE
);
1246 head
= (struct page
*)page_private(head
);
1248 __skb_fill_page_desc(skb
, new_frags
- 1, head
, 0, d_off
);
1249 skb_shinfo(skb
)->nr_frags
= new_frags
;
1252 skb_zcopy_clear(skb
, false);
1255 EXPORT_SYMBOL_GPL(skb_copy_ubufs
);
1258 * skb_clone - duplicate an sk_buff
1259 * @skb: buffer to clone
1260 * @gfp_mask: allocation priority
1262 * Duplicate an &sk_buff. The new one is not owned by a socket. Both
1263 * copies share the same packet data but not structure. The new
1264 * buffer has a reference count of 1. If the allocation fails the
1265 * function returns %NULL otherwise the new buffer is returned.
1267 * If this function is called from an interrupt gfp_mask() must be
1271 struct sk_buff
*skb_clone(struct sk_buff
*skb
, gfp_t gfp_mask
)
1273 struct sk_buff_fclones
*fclones
= container_of(skb
,
1274 struct sk_buff_fclones
,
1278 if (skb_orphan_frags(skb
, gfp_mask
))
1281 if (skb
->fclone
== SKB_FCLONE_ORIG
&&
1282 refcount_read(&fclones
->fclone_ref
) == 1) {
1284 refcount_set(&fclones
->fclone_ref
, 2);
1286 if (skb_pfmemalloc(skb
))
1287 gfp_mask
|= __GFP_MEMALLOC
;
1289 n
= kmem_cache_alloc(skbuff_head_cache
, gfp_mask
);
1293 n
->fclone
= SKB_FCLONE_UNAVAILABLE
;
1296 return __skb_clone(n
, skb
);
1298 EXPORT_SYMBOL(skb_clone
);
1300 void skb_headers_offset_update(struct sk_buff
*skb
, int off
)
1302 /* Only adjust this if it actually is csum_start rather than csum */
1303 if (skb
->ip_summed
== CHECKSUM_PARTIAL
)
1304 skb
->csum_start
+= off
;
1305 /* {transport,network,mac}_header and tail are relative to skb->head */
1306 skb
->transport_header
+= off
;
1307 skb
->network_header
+= off
;
1308 if (skb_mac_header_was_set(skb
))
1309 skb
->mac_header
+= off
;
1310 skb
->inner_transport_header
+= off
;
1311 skb
->inner_network_header
+= off
;
1312 skb
->inner_mac_header
+= off
;
1314 EXPORT_SYMBOL(skb_headers_offset_update
);
1316 void skb_copy_header(struct sk_buff
*new, const struct sk_buff
*old
)
1318 __copy_skb_header(new, old
);
1320 skb_shinfo(new)->gso_size
= skb_shinfo(old
)->gso_size
;
1321 skb_shinfo(new)->gso_segs
= skb_shinfo(old
)->gso_segs
;
1322 skb_shinfo(new)->gso_type
= skb_shinfo(old
)->gso_type
;
1324 EXPORT_SYMBOL(skb_copy_header
);
1326 static inline int skb_alloc_rx_flag(const struct sk_buff
*skb
)
1328 if (skb_pfmemalloc(skb
))
1329 return SKB_ALLOC_RX
;
1334 * skb_copy - create private copy of an sk_buff
1335 * @skb: buffer to copy
1336 * @gfp_mask: allocation priority
1338 * Make a copy of both an &sk_buff and its data. This is used when the
1339 * caller wishes to modify the data and needs a private copy of the
1340 * data to alter. Returns %NULL on failure or the pointer to the buffer
1341 * on success. The returned buffer has a reference count of 1.
1343 * As by-product this function converts non-linear &sk_buff to linear
1344 * one, so that &sk_buff becomes completely private and caller is allowed
1345 * to modify all the data of returned buffer. This means that this
1346 * function is not recommended for use in circumstances when only
1347 * header is going to be modified. Use pskb_copy() instead.
1350 struct sk_buff
*skb_copy(const struct sk_buff
*skb
, gfp_t gfp_mask
)
1352 int headerlen
= skb_headroom(skb
);
1353 unsigned int size
= skb_end_offset(skb
) + skb
->data_len
;
1354 struct sk_buff
*n
= __alloc_skb(size
, gfp_mask
,
1355 skb_alloc_rx_flag(skb
), NUMA_NO_NODE
);
1360 /* Set the data pointer */
1361 skb_reserve(n
, headerlen
);
1362 /* Set the tail pointer and length */
1363 skb_put(n
, skb
->len
);
1365 BUG_ON(skb_copy_bits(skb
, -headerlen
, n
->head
, headerlen
+ skb
->len
));
1367 skb_copy_header(n
, skb
);
1370 EXPORT_SYMBOL(skb_copy
);
1373 * __pskb_copy_fclone - create copy of an sk_buff with private head.
1374 * @skb: buffer to copy
1375 * @headroom: headroom of new skb
1376 * @gfp_mask: allocation priority
1377 * @fclone: if true allocate the copy of the skb from the fclone
1378 * cache instead of the head cache; it is recommended to set this
1379 * to true for the cases where the copy will likely be cloned
1381 * Make a copy of both an &sk_buff and part of its data, located
1382 * in header. Fragmented data remain shared. This is used when
1383 * the caller wishes to modify only header of &sk_buff and needs
1384 * private copy of the header to alter. Returns %NULL on failure
1385 * or the pointer to the buffer on success.
1386 * The returned buffer has a reference count of 1.
1389 struct sk_buff
*__pskb_copy_fclone(struct sk_buff
*skb
, int headroom
,
1390 gfp_t gfp_mask
, bool fclone
)
1392 unsigned int size
= skb_headlen(skb
) + headroom
;
1393 int flags
= skb_alloc_rx_flag(skb
) | (fclone
? SKB_ALLOC_FCLONE
: 0);
1394 struct sk_buff
*n
= __alloc_skb(size
, gfp_mask
, flags
, NUMA_NO_NODE
);
1399 /* Set the data pointer */
1400 skb_reserve(n
, headroom
);
1401 /* Set the tail pointer and length */
1402 skb_put(n
, skb_headlen(skb
));
1403 /* Copy the bytes */
1404 skb_copy_from_linear_data(skb
, n
->data
, n
->len
);
1406 n
->truesize
+= skb
->data_len
;
1407 n
->data_len
= skb
->data_len
;
1410 if (skb_shinfo(skb
)->nr_frags
) {
1413 if (skb_orphan_frags(skb
, gfp_mask
) ||
1414 skb_zerocopy_clone(n
, skb
, gfp_mask
)) {
1419 for (i
= 0; i
< skb_shinfo(skb
)->nr_frags
; i
++) {
1420 skb_shinfo(n
)->frags
[i
] = skb_shinfo(skb
)->frags
[i
];
1421 skb_frag_ref(skb
, i
);
1423 skb_shinfo(n
)->nr_frags
= i
;
1426 if (skb_has_frag_list(skb
)) {
1427 skb_shinfo(n
)->frag_list
= skb_shinfo(skb
)->frag_list
;
1428 skb_clone_fraglist(n
);
1431 skb_copy_header(n
, skb
);
1435 EXPORT_SYMBOL(__pskb_copy_fclone
);
1438 * pskb_expand_head - reallocate header of &sk_buff
1439 * @skb: buffer to reallocate
1440 * @nhead: room to add at head
1441 * @ntail: room to add at tail
1442 * @gfp_mask: allocation priority
1444 * Expands (or creates identical copy, if @nhead and @ntail are zero)
1445 * header of @skb. &sk_buff itself is not changed. &sk_buff MUST have
1446 * reference count of 1. Returns zero in the case of success or error,
1447 * if expansion failed. In the last case, &sk_buff is not changed.
1449 * All the pointers pointing into skb header may change and must be
1450 * reloaded after call to this function.
1453 int pskb_expand_head(struct sk_buff
*skb
, int nhead
, int ntail
,
1456 int i
, osize
= skb_end_offset(skb
);
1457 int size
= osize
+ nhead
+ ntail
;
1463 BUG_ON(skb_shared(skb
));
1465 size
= SKB_DATA_ALIGN(size
);
1467 if (skb_pfmemalloc(skb
))
1468 gfp_mask
|= __GFP_MEMALLOC
;
1469 data
= kmalloc_reserve(size
+ SKB_DATA_ALIGN(sizeof(struct skb_shared_info
)),
1470 gfp_mask
, NUMA_NO_NODE
, NULL
);
1473 size
= SKB_WITH_OVERHEAD(ksize(data
));
1475 /* Copy only real data... and, alas, header. This should be
1476 * optimized for the cases when header is void.
1478 memcpy(data
+ nhead
, skb
->head
, skb_tail_pointer(skb
) - skb
->head
);
1480 memcpy((struct skb_shared_info
*)(data
+ size
),
1482 offsetof(struct skb_shared_info
, frags
[skb_shinfo(skb
)->nr_frags
]));
1485 * if shinfo is shared we must drop the old head gracefully, but if it
1486 * is not we can just drop the old head and let the existing refcount
1487 * be since all we did is relocate the values
1489 if (skb_cloned(skb
)) {
1490 if (skb_orphan_frags(skb
, gfp_mask
))
1493 refcount_inc(&skb_uarg(skb
)->refcnt
);
1494 for (i
= 0; i
< skb_shinfo(skb
)->nr_frags
; i
++)
1495 skb_frag_ref(skb
, i
);
1497 if (skb_has_frag_list(skb
))
1498 skb_clone_fraglist(skb
);
1500 skb_release_data(skb
);
1504 off
= (data
+ nhead
) - skb
->head
;
1509 #ifdef NET_SKBUFF_DATA_USES_OFFSET
1513 skb
->end
= skb
->head
+ size
;
1516 skb_headers_offset_update(skb
, nhead
);
1520 atomic_set(&skb_shinfo(skb
)->dataref
, 1);
1522 skb_metadata_clear(skb
);
1524 /* It is not generally safe to change skb->truesize.
1525 * For the moment, we really care of rx path, or
1526 * when skb is orphaned (not attached to a socket).
1528 if (!skb
->sk
|| skb
->destructor
== sock_edemux
)
1529 skb
->truesize
+= size
- osize
;
1538 EXPORT_SYMBOL(pskb_expand_head
);
1540 /* Make private copy of skb with writable head and some headroom */
1542 struct sk_buff
*skb_realloc_headroom(struct sk_buff
*skb
, unsigned int headroom
)
1544 struct sk_buff
*skb2
;
1545 int delta
= headroom
- skb_headroom(skb
);
1548 skb2
= pskb_copy(skb
, GFP_ATOMIC
);
1550 skb2
= skb_clone(skb
, GFP_ATOMIC
);
1551 if (skb2
&& pskb_expand_head(skb2
, SKB_DATA_ALIGN(delta
), 0,
1559 EXPORT_SYMBOL(skb_realloc_headroom
);
1562 * skb_copy_expand - copy and expand sk_buff
1563 * @skb: buffer to copy
1564 * @newheadroom: new free bytes at head
1565 * @newtailroom: new free bytes at tail
1566 * @gfp_mask: allocation priority
1568 * Make a copy of both an &sk_buff and its data and while doing so
1569 * allocate additional space.
1571 * This is used when the caller wishes to modify the data and needs a
1572 * private copy of the data to alter as well as more space for new fields.
1573 * Returns %NULL on failure or the pointer to the buffer
1574 * on success. The returned buffer has a reference count of 1.
1576 * You must pass %GFP_ATOMIC as the allocation priority if this function
1577 * is called from an interrupt.
1579 struct sk_buff
*skb_copy_expand(const struct sk_buff
*skb
,
1580 int newheadroom
, int newtailroom
,
1584 * Allocate the copy buffer
1586 struct sk_buff
*n
= __alloc_skb(newheadroom
+ skb
->len
+ newtailroom
,
1587 gfp_mask
, skb_alloc_rx_flag(skb
),
1589 int oldheadroom
= skb_headroom(skb
);
1590 int head_copy_len
, head_copy_off
;
1595 skb_reserve(n
, newheadroom
);
1597 /* Set the tail pointer and length */
1598 skb_put(n
, skb
->len
);
1600 head_copy_len
= oldheadroom
;
1602 if (newheadroom
<= head_copy_len
)
1603 head_copy_len
= newheadroom
;
1605 head_copy_off
= newheadroom
- head_copy_len
;
1607 /* Copy the linear header and data. */
1608 BUG_ON(skb_copy_bits(skb
, -head_copy_len
, n
->head
+ head_copy_off
,
1609 skb
->len
+ head_copy_len
));
1611 skb_copy_header(n
, skb
);
1613 skb_headers_offset_update(n
, newheadroom
- oldheadroom
);
1617 EXPORT_SYMBOL(skb_copy_expand
);
1620 * __skb_pad - zero pad the tail of an skb
1621 * @skb: buffer to pad
1622 * @pad: space to pad
1623 * @free_on_error: free buffer on error
1625 * Ensure that a buffer is followed by a padding area that is zero
1626 * filled. Used by network drivers which may DMA or transfer data
1627 * beyond the buffer end onto the wire.
1629 * May return error in out of memory cases. The skb is freed on error
1630 * if @free_on_error is true.
1633 int __skb_pad(struct sk_buff
*skb
, int pad
, bool free_on_error
)
1638 /* If the skbuff is non linear tailroom is always zero.. */
1639 if (!skb_cloned(skb
) && skb_tailroom(skb
) >= pad
) {
1640 memset(skb
->data
+skb
->len
, 0, pad
);
1644 ntail
= skb
->data_len
+ pad
- (skb
->end
- skb
->tail
);
1645 if (likely(skb_cloned(skb
) || ntail
> 0)) {
1646 err
= pskb_expand_head(skb
, 0, ntail
, GFP_ATOMIC
);
1651 /* FIXME: The use of this function with non-linear skb's really needs
1654 err
= skb_linearize(skb
);
1658 memset(skb
->data
+ skb
->len
, 0, pad
);
1666 EXPORT_SYMBOL(__skb_pad
);
1669 * pskb_put - add data to the tail of a potentially fragmented buffer
1670 * @skb: start of the buffer to use
1671 * @tail: tail fragment of the buffer to use
1672 * @len: amount of data to add
1674 * This function extends the used data area of the potentially
1675 * fragmented buffer. @tail must be the last fragment of @skb -- or
1676 * @skb itself. If this would exceed the total buffer size the kernel
1677 * will panic. A pointer to the first byte of the extra data is
1681 void *pskb_put(struct sk_buff
*skb
, struct sk_buff
*tail
, int len
)
1684 skb
->data_len
+= len
;
1687 return skb_put(tail
, len
);
1689 EXPORT_SYMBOL_GPL(pskb_put
);
1692 * skb_put - add data to a buffer
1693 * @skb: buffer to use
1694 * @len: amount of data to add
1696 * This function extends the used data area of the buffer. If this would
1697 * exceed the total buffer size the kernel will panic. A pointer to the
1698 * first byte of the extra data is returned.
1700 void *skb_put(struct sk_buff
*skb
, unsigned int len
)
1702 void *tmp
= skb_tail_pointer(skb
);
1703 SKB_LINEAR_ASSERT(skb
);
1706 if (unlikely(skb
->tail
> skb
->end
))
1707 skb_over_panic(skb
, len
, __builtin_return_address(0));
1710 EXPORT_SYMBOL(skb_put
);
1713 * skb_push - add data to the start of a buffer
1714 * @skb: buffer to use
1715 * @len: amount of data to add
1717 * This function extends the used data area of the buffer at the buffer
1718 * start. If this would exceed the total buffer headroom the kernel will
1719 * panic. A pointer to the first byte of the extra data is returned.
1721 void *skb_push(struct sk_buff
*skb
, unsigned int len
)
1725 if (unlikely(skb
->data
< skb
->head
))
1726 skb_under_panic(skb
, len
, __builtin_return_address(0));
1729 EXPORT_SYMBOL(skb_push
);
1732 * skb_pull - remove data from the start of a buffer
1733 * @skb: buffer to use
1734 * @len: amount of data to remove
1736 * This function removes data from the start of a buffer, returning
1737 * the memory to the headroom. A pointer to the next data in the buffer
1738 * is returned. Once the data has been pulled future pushes will overwrite
1741 void *skb_pull(struct sk_buff
*skb
, unsigned int len
)
1743 return skb_pull_inline(skb
, len
);
1745 EXPORT_SYMBOL(skb_pull
);
1748 * skb_trim - remove end from a buffer
1749 * @skb: buffer to alter
1752 * Cut the length of a buffer down by removing data from the tail. If
1753 * the buffer is already under the length specified it is not modified.
1754 * The skb must be linear.
1756 void skb_trim(struct sk_buff
*skb
, unsigned int len
)
1759 __skb_trim(skb
, len
);
1761 EXPORT_SYMBOL(skb_trim
);
1763 /* Trims skb to length len. It can change skb pointers.
1766 int ___pskb_trim(struct sk_buff
*skb
, unsigned int len
)
1768 struct sk_buff
**fragp
;
1769 struct sk_buff
*frag
;
1770 int offset
= skb_headlen(skb
);
1771 int nfrags
= skb_shinfo(skb
)->nr_frags
;
1775 if (skb_cloned(skb
) &&
1776 unlikely((err
= pskb_expand_head(skb
, 0, 0, GFP_ATOMIC
))))
1783 for (; i
< nfrags
; i
++) {
1784 int end
= offset
+ skb_frag_size(&skb_shinfo(skb
)->frags
[i
]);
1791 skb_frag_size_set(&skb_shinfo(skb
)->frags
[i
++], len
- offset
);
1794 skb_shinfo(skb
)->nr_frags
= i
;
1796 for (; i
< nfrags
; i
++)
1797 skb_frag_unref(skb
, i
);
1799 if (skb_has_frag_list(skb
))
1800 skb_drop_fraglist(skb
);
1804 for (fragp
= &skb_shinfo(skb
)->frag_list
; (frag
= *fragp
);
1805 fragp
= &frag
->next
) {
1806 int end
= offset
+ frag
->len
;
1808 if (skb_shared(frag
)) {
1809 struct sk_buff
*nfrag
;
1811 nfrag
= skb_clone(frag
, GFP_ATOMIC
);
1812 if (unlikely(!nfrag
))
1815 nfrag
->next
= frag
->next
;
1827 unlikely((err
= pskb_trim(frag
, len
- offset
))))
1831 skb_drop_list(&frag
->next
);
1836 if (len
> skb_headlen(skb
)) {
1837 skb
->data_len
-= skb
->len
- len
;
1842 skb_set_tail_pointer(skb
, len
);
1845 if (!skb
->sk
|| skb
->destructor
== sock_edemux
)
1849 EXPORT_SYMBOL(___pskb_trim
);
1851 /* Note : use pskb_trim_rcsum() instead of calling this directly
1853 int pskb_trim_rcsum_slow(struct sk_buff
*skb
, unsigned int len
)
1855 if (skb
->ip_summed
== CHECKSUM_COMPLETE
) {
1856 int delta
= skb
->len
- len
;
1858 skb
->csum
= csum_block_sub(skb
->csum
,
1859 skb_checksum(skb
, len
, delta
, 0),
1862 return __pskb_trim(skb
, len
);
1864 EXPORT_SYMBOL(pskb_trim_rcsum_slow
);
1867 * __pskb_pull_tail - advance tail of skb header
1868 * @skb: buffer to reallocate
1869 * @delta: number of bytes to advance tail
1871 * The function makes a sense only on a fragmented &sk_buff,
1872 * it expands header moving its tail forward and copying necessary
1873 * data from fragmented part.
1875 * &sk_buff MUST have reference count of 1.
1877 * Returns %NULL (and &sk_buff does not change) if pull failed
1878 * or value of new tail of skb in the case of success.
1880 * All the pointers pointing into skb header may change and must be
1881 * reloaded after call to this function.
1884 /* Moves tail of skb head forward, copying data from fragmented part,
1885 * when it is necessary.
1886 * 1. It may fail due to malloc failure.
1887 * 2. It may change skb pointers.
1889 * It is pretty complicated. Luckily, it is called only in exceptional cases.
1891 void *__pskb_pull_tail(struct sk_buff
*skb
, int delta
)
1893 /* If skb has not enough free space at tail, get new one
1894 * plus 128 bytes for future expansions. If we have enough
1895 * room at tail, reallocate without expansion only if skb is cloned.
1897 int i
, k
, eat
= (skb
->tail
+ delta
) - skb
->end
;
1899 if (eat
> 0 || skb_cloned(skb
)) {
1900 if (pskb_expand_head(skb
, 0, eat
> 0 ? eat
+ 128 : 0,
1905 BUG_ON(skb_copy_bits(skb
, skb_headlen(skb
),
1906 skb_tail_pointer(skb
), delta
));
1908 /* Optimization: no fragments, no reasons to preestimate
1909 * size of pulled pages. Superb.
1911 if (!skb_has_frag_list(skb
))
1914 /* Estimate size of pulled pages. */
1916 for (i
= 0; i
< skb_shinfo(skb
)->nr_frags
; i
++) {
1917 int size
= skb_frag_size(&skb_shinfo(skb
)->frags
[i
]);
1924 /* If we need update frag list, we are in troubles.
1925 * Certainly, it is possible to add an offset to skb data,
1926 * but taking into account that pulling is expected to
1927 * be very rare operation, it is worth to fight against
1928 * further bloating skb head and crucify ourselves here instead.
1929 * Pure masohism, indeed. 8)8)
1932 struct sk_buff
*list
= skb_shinfo(skb
)->frag_list
;
1933 struct sk_buff
*clone
= NULL
;
1934 struct sk_buff
*insp
= NULL
;
1937 if (list
->len
<= eat
) {
1938 /* Eaten as whole. */
1943 /* Eaten partially. */
1945 if (skb_shared(list
)) {
1946 /* Sucks! We need to fork list. :-( */
1947 clone
= skb_clone(list
, GFP_ATOMIC
);
1953 /* This may be pulled without
1957 if (!pskb_pull(list
, eat
)) {
1965 /* Free pulled out fragments. */
1966 while ((list
= skb_shinfo(skb
)->frag_list
) != insp
) {
1967 skb_shinfo(skb
)->frag_list
= list
->next
;
1970 /* And insert new clone at head. */
1973 skb_shinfo(skb
)->frag_list
= clone
;
1976 /* Success! Now we may commit changes to skb data. */
1981 for (i
= 0; i
< skb_shinfo(skb
)->nr_frags
; i
++) {
1982 int size
= skb_frag_size(&skb_shinfo(skb
)->frags
[i
]);
1985 skb_frag_unref(skb
, i
);
1988 skb_shinfo(skb
)->frags
[k
] = skb_shinfo(skb
)->frags
[i
];
1990 skb_shinfo(skb
)->frags
[k
].page_offset
+= eat
;
1991 skb_frag_size_sub(&skb_shinfo(skb
)->frags
[k
], eat
);
1999 skb_shinfo(skb
)->nr_frags
= k
;
2003 skb
->data_len
-= delta
;
2006 skb_zcopy_clear(skb
, false);
2008 return skb_tail_pointer(skb
);
2010 EXPORT_SYMBOL(__pskb_pull_tail
);
2013 * skb_copy_bits - copy bits from skb to kernel buffer
2015 * @offset: offset in source
2016 * @to: destination buffer
2017 * @len: number of bytes to copy
2019 * Copy the specified number of bytes from the source skb to the
2020 * destination buffer.
2023 * If its prototype is ever changed,
2024 * check arch/{*}/net/{*}.S files,
2025 * since it is called from BPF assembly code.
2027 int skb_copy_bits(const struct sk_buff
*skb
, int offset
, void *to
, int len
)
2029 int start
= skb_headlen(skb
);
2030 struct sk_buff
*frag_iter
;
2033 if (offset
> (int)skb
->len
- len
)
2037 if ((copy
= start
- offset
) > 0) {
2040 skb_copy_from_linear_data_offset(skb
, offset
, to
, copy
);
2041 if ((len
-= copy
) == 0)
2047 for (i
= 0; i
< skb_shinfo(skb
)->nr_frags
; i
++) {
2049 skb_frag_t
*f
= &skb_shinfo(skb
)->frags
[i
];
2051 WARN_ON(start
> offset
+ len
);
2053 end
= start
+ skb_frag_size(f
);
2054 if ((copy
= end
- offset
) > 0) {
2055 u32 p_off
, p_len
, copied
;
2062 skb_frag_foreach_page(f
,
2063 f
->page_offset
+ offset
- start
,
2064 copy
, p
, p_off
, p_len
, copied
) {
2065 vaddr
= kmap_atomic(p
);
2066 memcpy(to
+ copied
, vaddr
+ p_off
, p_len
);
2067 kunmap_atomic(vaddr
);
2070 if ((len
-= copy
) == 0)
2078 skb_walk_frags(skb
, frag_iter
) {
2081 WARN_ON(start
> offset
+ len
);
2083 end
= start
+ frag_iter
->len
;
2084 if ((copy
= end
- offset
) > 0) {
2087 if (skb_copy_bits(frag_iter
, offset
- start
, to
, copy
))
2089 if ((len
-= copy
) == 0)
2103 EXPORT_SYMBOL(skb_copy_bits
);
2106 * Callback from splice_to_pipe(), if we need to release some pages
2107 * at the end of the spd in case we error'ed out in filling the pipe.
2109 static void sock_spd_release(struct splice_pipe_desc
*spd
, unsigned int i
)
2111 put_page(spd
->pages
[i
]);
2114 static struct page
*linear_to_page(struct page
*page
, unsigned int *len
,
2115 unsigned int *offset
,
2118 struct page_frag
*pfrag
= sk_page_frag(sk
);
2120 if (!sk_page_frag_refill(sk
, pfrag
))
2123 *len
= min_t(unsigned int, *len
, pfrag
->size
- pfrag
->offset
);
2125 memcpy(page_address(pfrag
->page
) + pfrag
->offset
,
2126 page_address(page
) + *offset
, *len
);
2127 *offset
= pfrag
->offset
;
2128 pfrag
->offset
+= *len
;
2133 static bool spd_can_coalesce(const struct splice_pipe_desc
*spd
,
2135 unsigned int offset
)
2137 return spd
->nr_pages
&&
2138 spd
->pages
[spd
->nr_pages
- 1] == page
&&
2139 (spd
->partial
[spd
->nr_pages
- 1].offset
+
2140 spd
->partial
[spd
->nr_pages
- 1].len
== offset
);
2144 * Fill page/offset/length into spd, if it can hold more pages.
2146 static bool spd_fill_page(struct splice_pipe_desc
*spd
,
2147 struct pipe_inode_info
*pipe
, struct page
*page
,
2148 unsigned int *len
, unsigned int offset
,
2152 if (unlikely(spd
->nr_pages
== MAX_SKB_FRAGS
))
2156 page
= linear_to_page(page
, len
, &offset
, sk
);
2160 if (spd_can_coalesce(spd
, page
, offset
)) {
2161 spd
->partial
[spd
->nr_pages
- 1].len
+= *len
;
2165 spd
->pages
[spd
->nr_pages
] = page
;
2166 spd
->partial
[spd
->nr_pages
].len
= *len
;
2167 spd
->partial
[spd
->nr_pages
].offset
= offset
;
2173 static bool __splice_segment(struct page
*page
, unsigned int poff
,
2174 unsigned int plen
, unsigned int *off
,
2176 struct splice_pipe_desc
*spd
, bool linear
,
2178 struct pipe_inode_info
*pipe
)
2183 /* skip this segment if already processed */
2189 /* ignore any bits we already processed */
2195 unsigned int flen
= min(*len
, plen
);
2197 if (spd_fill_page(spd
, pipe
, page
, &flen
, poff
,
2203 } while (*len
&& plen
);
2209 * Map linear and fragment data from the skb to spd. It reports true if the
2210 * pipe is full or if we already spliced the requested length.
2212 static bool __skb_splice_bits(struct sk_buff
*skb
, struct pipe_inode_info
*pipe
,
2213 unsigned int *offset
, unsigned int *len
,
2214 struct splice_pipe_desc
*spd
, struct sock
*sk
)
2217 struct sk_buff
*iter
;
2219 /* map the linear part :
2220 * If skb->head_frag is set, this 'linear' part is backed by a
2221 * fragment, and if the head is not shared with any clones then
2222 * we can avoid a copy since we own the head portion of this page.
2224 if (__splice_segment(virt_to_page(skb
->data
),
2225 (unsigned long) skb
->data
& (PAGE_SIZE
- 1),
2228 skb_head_is_locked(skb
),
2233 * then map the fragments
2235 for (seg
= 0; seg
< skb_shinfo(skb
)->nr_frags
; seg
++) {
2236 const skb_frag_t
*f
= &skb_shinfo(skb
)->frags
[seg
];
2238 if (__splice_segment(skb_frag_page(f
),
2239 f
->page_offset
, skb_frag_size(f
),
2240 offset
, len
, spd
, false, sk
, pipe
))
2244 skb_walk_frags(skb
, iter
) {
2245 if (*offset
>= iter
->len
) {
2246 *offset
-= iter
->len
;
2249 /* __skb_splice_bits() only fails if the output has no room
2250 * left, so no point in going over the frag_list for the error
2253 if (__skb_splice_bits(iter
, pipe
, offset
, len
, spd
, sk
))
2261 * Map data from the skb to a pipe. Should handle both the linear part,
2262 * the fragments, and the frag list.
2264 int skb_splice_bits(struct sk_buff
*skb
, struct sock
*sk
, unsigned int offset
,
2265 struct pipe_inode_info
*pipe
, unsigned int tlen
,
2268 struct partial_page partial
[MAX_SKB_FRAGS
];
2269 struct page
*pages
[MAX_SKB_FRAGS
];
2270 struct splice_pipe_desc spd
= {
2273 .nr_pages_max
= MAX_SKB_FRAGS
,
2274 .ops
= &nosteal_pipe_buf_ops
,
2275 .spd_release
= sock_spd_release
,
2279 __skb_splice_bits(skb
, pipe
, &offset
, &tlen
, &spd
, sk
);
2282 ret
= splice_to_pipe(pipe
, &spd
);
2286 EXPORT_SYMBOL_GPL(skb_splice_bits
);
2288 /* Send skb data on a socket. Socket must be locked. */
2289 int skb_send_sock_locked(struct sock
*sk
, struct sk_buff
*skb
, int offset
,
2292 unsigned int orig_len
= len
;
2293 struct sk_buff
*head
= skb
;
2294 unsigned short fragidx
;
2299 /* Deal with head data */
2300 while (offset
< skb_headlen(skb
) && len
) {
2304 slen
= min_t(int, len
, skb_headlen(skb
) - offset
);
2305 kv
.iov_base
= skb
->data
+ offset
;
2307 memset(&msg
, 0, sizeof(msg
));
2309 ret
= kernel_sendmsg_locked(sk
, &msg
, &kv
, 1, slen
);
2317 /* All the data was skb head? */
2321 /* Make offset relative to start of frags */
2322 offset
-= skb_headlen(skb
);
2324 /* Find where we are in frag list */
2325 for (fragidx
= 0; fragidx
< skb_shinfo(skb
)->nr_frags
; fragidx
++) {
2326 skb_frag_t
*frag
= &skb_shinfo(skb
)->frags
[fragidx
];
2328 if (offset
< frag
->size
)
2331 offset
-= frag
->size
;
2334 for (; len
&& fragidx
< skb_shinfo(skb
)->nr_frags
; fragidx
++) {
2335 skb_frag_t
*frag
= &skb_shinfo(skb
)->frags
[fragidx
];
2337 slen
= min_t(size_t, len
, frag
->size
- offset
);
2340 ret
= kernel_sendpage_locked(sk
, frag
->page
.p
,
2341 frag
->page_offset
+ offset
,
2342 slen
, MSG_DONTWAIT
);
2355 /* Process any frag lists */
2358 if (skb_has_frag_list(skb
)) {
2359 skb
= skb_shinfo(skb
)->frag_list
;
2362 } else if (skb
->next
) {
2369 return orig_len
- len
;
2372 return orig_len
== len
? ret
: orig_len
- len
;
2374 EXPORT_SYMBOL_GPL(skb_send_sock_locked
);
2377 * skb_store_bits - store bits from kernel buffer to skb
2378 * @skb: destination buffer
2379 * @offset: offset in destination
2380 * @from: source buffer
2381 * @len: number of bytes to copy
2383 * Copy the specified number of bytes from the source buffer to the
2384 * destination skb. This function handles all the messy bits of
2385 * traversing fragment lists and such.
2388 int skb_store_bits(struct sk_buff
*skb
, int offset
, const void *from
, int len
)
2390 int start
= skb_headlen(skb
);
2391 struct sk_buff
*frag_iter
;
2394 if (offset
> (int)skb
->len
- len
)
2397 if ((copy
= start
- offset
) > 0) {
2400 skb_copy_to_linear_data_offset(skb
, offset
, from
, copy
);
2401 if ((len
-= copy
) == 0)
2407 for (i
= 0; i
< skb_shinfo(skb
)->nr_frags
; i
++) {
2408 skb_frag_t
*frag
= &skb_shinfo(skb
)->frags
[i
];
2411 WARN_ON(start
> offset
+ len
);
2413 end
= start
+ skb_frag_size(frag
);
2414 if ((copy
= end
- offset
) > 0) {
2415 u32 p_off
, p_len
, copied
;
2422 skb_frag_foreach_page(frag
,
2423 frag
->page_offset
+ offset
- start
,
2424 copy
, p
, p_off
, p_len
, copied
) {
2425 vaddr
= kmap_atomic(p
);
2426 memcpy(vaddr
+ p_off
, from
+ copied
, p_len
);
2427 kunmap_atomic(vaddr
);
2430 if ((len
-= copy
) == 0)
2438 skb_walk_frags(skb
, frag_iter
) {
2441 WARN_ON(start
> offset
+ len
);
2443 end
= start
+ frag_iter
->len
;
2444 if ((copy
= end
- offset
) > 0) {
2447 if (skb_store_bits(frag_iter
, offset
- start
,
2450 if ((len
-= copy
) == 0)
2463 EXPORT_SYMBOL(skb_store_bits
);
2465 /* Checksum skb data. */
2466 __wsum
__skb_checksum(const struct sk_buff
*skb
, int offset
, int len
,
2467 __wsum csum
, const struct skb_checksum_ops
*ops
)
2469 int start
= skb_headlen(skb
);
2470 int i
, copy
= start
- offset
;
2471 struct sk_buff
*frag_iter
;
2474 /* Checksum header. */
2478 csum
= ops
->update(skb
->data
+ offset
, copy
, csum
);
2479 if ((len
-= copy
) == 0)
2485 for (i
= 0; i
< skb_shinfo(skb
)->nr_frags
; i
++) {
2487 skb_frag_t
*frag
= &skb_shinfo(skb
)->frags
[i
];
2489 WARN_ON(start
> offset
+ len
);
2491 end
= start
+ skb_frag_size(frag
);
2492 if ((copy
= end
- offset
) > 0) {
2493 u32 p_off
, p_len
, copied
;
2501 skb_frag_foreach_page(frag
,
2502 frag
->page_offset
+ offset
- start
,
2503 copy
, p
, p_off
, p_len
, copied
) {
2504 vaddr
= kmap_atomic(p
);
2505 csum2
= ops
->update(vaddr
+ p_off
, p_len
, 0);
2506 kunmap_atomic(vaddr
);
2507 csum
= ops
->combine(csum
, csum2
, pos
, p_len
);
2518 skb_walk_frags(skb
, frag_iter
) {
2521 WARN_ON(start
> offset
+ len
);
2523 end
= start
+ frag_iter
->len
;
2524 if ((copy
= end
- offset
) > 0) {
2528 csum2
= __skb_checksum(frag_iter
, offset
- start
,
2530 csum
= ops
->combine(csum
, csum2
, pos
, copy
);
2531 if ((len
-= copy
) == 0)
2542 EXPORT_SYMBOL(__skb_checksum
);
2544 __wsum
skb_checksum(const struct sk_buff
*skb
, int offset
,
2545 int len
, __wsum csum
)
2547 const struct skb_checksum_ops ops
= {
2548 .update
= csum_partial_ext
,
2549 .combine
= csum_block_add_ext
,
2552 return __skb_checksum(skb
, offset
, len
, csum
, &ops
);
2554 EXPORT_SYMBOL(skb_checksum
);
2556 /* Both of above in one bottle. */
2558 __wsum
skb_copy_and_csum_bits(const struct sk_buff
*skb
, int offset
,
2559 u8
*to
, int len
, __wsum csum
)
2561 int start
= skb_headlen(skb
);
2562 int i
, copy
= start
- offset
;
2563 struct sk_buff
*frag_iter
;
2570 csum
= csum_partial_copy_nocheck(skb
->data
+ offset
, to
,
2572 if ((len
-= copy
) == 0)
2579 for (i
= 0; i
< skb_shinfo(skb
)->nr_frags
; i
++) {
2582 WARN_ON(start
> offset
+ len
);
2584 end
= start
+ skb_frag_size(&skb_shinfo(skb
)->frags
[i
]);
2585 if ((copy
= end
- offset
) > 0) {
2586 skb_frag_t
*frag
= &skb_shinfo(skb
)->frags
[i
];
2587 u32 p_off
, p_len
, copied
;
2595 skb_frag_foreach_page(frag
,
2596 frag
->page_offset
+ offset
- start
,
2597 copy
, p
, p_off
, p_len
, copied
) {
2598 vaddr
= kmap_atomic(p
);
2599 csum2
= csum_partial_copy_nocheck(vaddr
+ p_off
,
2602 kunmap_atomic(vaddr
);
2603 csum
= csum_block_add(csum
, csum2
, pos
);
2615 skb_walk_frags(skb
, frag_iter
) {
2619 WARN_ON(start
> offset
+ len
);
2621 end
= start
+ frag_iter
->len
;
2622 if ((copy
= end
- offset
) > 0) {
2625 csum2
= skb_copy_and_csum_bits(frag_iter
,
2628 csum
= csum_block_add(csum
, csum2
, pos
);
2629 if ((len
-= copy
) == 0)
2640 EXPORT_SYMBOL(skb_copy_and_csum_bits
);
2642 __sum16
__skb_checksum_complete_head(struct sk_buff
*skb
, int len
)
2646 sum
= csum_fold(skb_checksum(skb
, 0, len
, skb
->csum
));
2647 /* See comments in __skb_checksum_complete(). */
2649 if (unlikely(skb
->ip_summed
== CHECKSUM_COMPLETE
) &&
2650 !skb
->csum_complete_sw
)
2651 netdev_rx_csum_fault(skb
->dev
, skb
);
2653 if (!skb_shared(skb
))
2654 skb
->csum_valid
= !sum
;
2657 EXPORT_SYMBOL(__skb_checksum_complete_head
);
2659 /* This function assumes skb->csum already holds pseudo header's checksum,
2660 * which has been changed from the hardware checksum, for example, by
2661 * __skb_checksum_validate_complete(). And, the original skb->csum must
2662 * have been validated unsuccessfully for CHECKSUM_COMPLETE case.
2664 * It returns non-zero if the recomputed checksum is still invalid, otherwise
2665 * zero. The new checksum is stored back into skb->csum unless the skb is
2668 __sum16
__skb_checksum_complete(struct sk_buff
*skb
)
2673 csum
= skb_checksum(skb
, 0, skb
->len
, 0);
2675 sum
= csum_fold(csum_add(skb
->csum
, csum
));
2676 /* This check is inverted, because we already knew the hardware
2677 * checksum is invalid before calling this function. So, if the
2678 * re-computed checksum is valid instead, then we have a mismatch
2679 * between the original skb->csum and skb_checksum(). This means either
2680 * the original hardware checksum is incorrect or we screw up skb->csum
2681 * when moving skb->data around.
2684 if (unlikely(skb
->ip_summed
== CHECKSUM_COMPLETE
) &&
2685 !skb
->csum_complete_sw
)
2686 netdev_rx_csum_fault(skb
->dev
, skb
);
2689 if (!skb_shared(skb
)) {
2690 /* Save full packet checksum */
2692 skb
->ip_summed
= CHECKSUM_COMPLETE
;
2693 skb
->csum_complete_sw
= 1;
2694 skb
->csum_valid
= !sum
;
2699 EXPORT_SYMBOL(__skb_checksum_complete
);
2701 static __wsum
warn_crc32c_csum_update(const void *buff
, int len
, __wsum sum
)
2703 net_warn_ratelimited(
2704 "%s: attempt to compute crc32c without libcrc32c.ko\n",
2709 static __wsum
warn_crc32c_csum_combine(__wsum csum
, __wsum csum2
,
2710 int offset
, int len
)
2712 net_warn_ratelimited(
2713 "%s: attempt to compute crc32c without libcrc32c.ko\n",
2718 static const struct skb_checksum_ops default_crc32c_ops
= {
2719 .update
= warn_crc32c_csum_update
,
2720 .combine
= warn_crc32c_csum_combine
,
2723 const struct skb_checksum_ops
*crc32c_csum_stub __read_mostly
=
2724 &default_crc32c_ops
;
2725 EXPORT_SYMBOL(crc32c_csum_stub
);
2728 * skb_zerocopy_headlen - Calculate headroom needed for skb_zerocopy()
2729 * @from: source buffer
2731 * Calculates the amount of linear headroom needed in the 'to' skb passed
2732 * into skb_zerocopy().
2735 skb_zerocopy_headlen(const struct sk_buff
*from
)
2737 unsigned int hlen
= 0;
2739 if (!from
->head_frag
||
2740 skb_headlen(from
) < L1_CACHE_BYTES
||
2741 skb_shinfo(from
)->nr_frags
>= MAX_SKB_FRAGS
)
2742 hlen
= skb_headlen(from
);
2744 if (skb_has_frag_list(from
))
2749 EXPORT_SYMBOL_GPL(skb_zerocopy_headlen
);
2752 * skb_zerocopy - Zero copy skb to skb
2753 * @to: destination buffer
2754 * @from: source buffer
2755 * @len: number of bytes to copy from source buffer
2756 * @hlen: size of linear headroom in destination buffer
2758 * Copies up to `len` bytes from `from` to `to` by creating references
2759 * to the frags in the source buffer.
2761 * The `hlen` as calculated by skb_zerocopy_headlen() specifies the
2762 * headroom in the `to` buffer.
2765 * 0: everything is OK
2766 * -ENOMEM: couldn't orphan frags of @from due to lack of memory
2767 * -EFAULT: skb_copy_bits() found some problem with skb geometry
2770 skb_zerocopy(struct sk_buff
*to
, struct sk_buff
*from
, int len
, int hlen
)
2773 int plen
= 0; /* length of skb->head fragment */
2776 unsigned int offset
;
2778 BUG_ON(!from
->head_frag
&& !hlen
);
2780 /* dont bother with small payloads */
2781 if (len
<= skb_tailroom(to
))
2782 return skb_copy_bits(from
, 0, skb_put(to
, len
), len
);
2785 ret
= skb_copy_bits(from
, 0, skb_put(to
, hlen
), hlen
);
2790 plen
= min_t(int, skb_headlen(from
), len
);
2792 page
= virt_to_head_page(from
->head
);
2793 offset
= from
->data
- (unsigned char *)page_address(page
);
2794 __skb_fill_page_desc(to
, 0, page
, offset
, plen
);
2801 to
->truesize
+= len
+ plen
;
2802 to
->len
+= len
+ plen
;
2803 to
->data_len
+= len
+ plen
;
2805 if (unlikely(skb_orphan_frags(from
, GFP_ATOMIC
))) {
2809 skb_zerocopy_clone(to
, from
, GFP_ATOMIC
);
2811 for (i
= 0; i
< skb_shinfo(from
)->nr_frags
; i
++) {
2814 skb_shinfo(to
)->frags
[j
] = skb_shinfo(from
)->frags
[i
];
2815 skb_shinfo(to
)->frags
[j
].size
= min_t(int, skb_shinfo(to
)->frags
[j
].size
, len
);
2816 len
-= skb_shinfo(to
)->frags
[j
].size
;
2817 skb_frag_ref(to
, j
);
2820 skb_shinfo(to
)->nr_frags
= j
;
2824 EXPORT_SYMBOL_GPL(skb_zerocopy
);
2826 void skb_copy_and_csum_dev(const struct sk_buff
*skb
, u8
*to
)
2831 if (skb
->ip_summed
== CHECKSUM_PARTIAL
)
2832 csstart
= skb_checksum_start_offset(skb
);
2834 csstart
= skb_headlen(skb
);
2836 BUG_ON(csstart
> skb_headlen(skb
));
2838 skb_copy_from_linear_data(skb
, to
, csstart
);
2841 if (csstart
!= skb
->len
)
2842 csum
= skb_copy_and_csum_bits(skb
, csstart
, to
+ csstart
,
2843 skb
->len
- csstart
, 0);
2845 if (skb
->ip_summed
== CHECKSUM_PARTIAL
) {
2846 long csstuff
= csstart
+ skb
->csum_offset
;
2848 *((__sum16
*)(to
+ csstuff
)) = csum_fold(csum
);
2851 EXPORT_SYMBOL(skb_copy_and_csum_dev
);
2854 * skb_dequeue - remove from the head of the queue
2855 * @list: list to dequeue from
2857 * Remove the head of the list. The list lock is taken so the function
2858 * may be used safely with other locking list functions. The head item is
2859 * returned or %NULL if the list is empty.
2862 struct sk_buff
*skb_dequeue(struct sk_buff_head
*list
)
2864 unsigned long flags
;
2865 struct sk_buff
*result
;
2867 spin_lock_irqsave(&list
->lock
, flags
);
2868 result
= __skb_dequeue(list
);
2869 spin_unlock_irqrestore(&list
->lock
, flags
);
2872 EXPORT_SYMBOL(skb_dequeue
);
2875 * skb_dequeue_tail - remove from the tail of the queue
2876 * @list: list to dequeue from
2878 * Remove the tail of the list. The list lock is taken so the function
2879 * may be used safely with other locking list functions. The tail item is
2880 * returned or %NULL if the list is empty.
2882 struct sk_buff
*skb_dequeue_tail(struct sk_buff_head
*list
)
2884 unsigned long flags
;
2885 struct sk_buff
*result
;
2887 spin_lock_irqsave(&list
->lock
, flags
);
2888 result
= __skb_dequeue_tail(list
);
2889 spin_unlock_irqrestore(&list
->lock
, flags
);
2892 EXPORT_SYMBOL(skb_dequeue_tail
);
2895 * skb_queue_purge - empty a list
2896 * @list: list to empty
2898 * Delete all buffers on an &sk_buff list. Each buffer is removed from
2899 * the list and one reference dropped. This function takes the list
2900 * lock and is atomic with respect to other list locking functions.
2902 void skb_queue_purge(struct sk_buff_head
*list
)
2904 struct sk_buff
*skb
;
2905 while ((skb
= skb_dequeue(list
)) != NULL
)
2908 EXPORT_SYMBOL(skb_queue_purge
);
2911 * skb_rbtree_purge - empty a skb rbtree
2912 * @root: root of the rbtree to empty
2913 * Return value: the sum of truesizes of all purged skbs.
2915 * Delete all buffers on an &sk_buff rbtree. Each buffer is removed from
2916 * the list and one reference dropped. This function does not take
2917 * any lock. Synchronization should be handled by the caller (e.g., TCP
2918 * out-of-order queue is protected by the socket lock).
2920 unsigned int skb_rbtree_purge(struct rb_root
*root
)
2922 struct rb_node
*p
= rb_first(root
);
2923 unsigned int sum
= 0;
2926 struct sk_buff
*skb
= rb_entry(p
, struct sk_buff
, rbnode
);
2929 rb_erase(&skb
->rbnode
, root
);
2930 sum
+= skb
->truesize
;
2937 * skb_queue_head - queue a buffer at the list head
2938 * @list: list to use
2939 * @newsk: buffer to queue
2941 * Queue a buffer at the start of the list. This function takes the
2942 * list lock and can be used safely with other locking &sk_buff functions
2945 * A buffer cannot be placed on two lists at the same time.
2947 void skb_queue_head(struct sk_buff_head
*list
, struct sk_buff
*newsk
)
2949 unsigned long flags
;
2951 spin_lock_irqsave(&list
->lock
, flags
);
2952 __skb_queue_head(list
, newsk
);
2953 spin_unlock_irqrestore(&list
->lock
, flags
);
2955 EXPORT_SYMBOL(skb_queue_head
);
2958 * skb_queue_tail - queue a buffer at the list tail
2959 * @list: list to use
2960 * @newsk: buffer to queue
2962 * Queue a buffer at the tail of the list. This function takes the
2963 * list lock and can be used safely with other locking &sk_buff functions
2966 * A buffer cannot be placed on two lists at the same time.
2968 void skb_queue_tail(struct sk_buff_head
*list
, struct sk_buff
*newsk
)
2970 unsigned long flags
;
2972 spin_lock_irqsave(&list
->lock
, flags
);
2973 __skb_queue_tail(list
, newsk
);
2974 spin_unlock_irqrestore(&list
->lock
, flags
);
2976 EXPORT_SYMBOL(skb_queue_tail
);
2979 * skb_unlink - remove a buffer from a list
2980 * @skb: buffer to remove
2981 * @list: list to use
2983 * Remove a packet from a list. The list locks are taken and this
2984 * function is atomic with respect to other list locked calls
2986 * You must know what list the SKB is on.
2988 void skb_unlink(struct sk_buff
*skb
, struct sk_buff_head
*list
)
2990 unsigned long flags
;
2992 spin_lock_irqsave(&list
->lock
, flags
);
2993 __skb_unlink(skb
, list
);
2994 spin_unlock_irqrestore(&list
->lock
, flags
);
2996 EXPORT_SYMBOL(skb_unlink
);
2999 * skb_append - append a buffer
3000 * @old: buffer to insert after
3001 * @newsk: buffer to insert
3002 * @list: list to use
3004 * Place a packet after a given packet in a list. The list locks are taken
3005 * and this function is atomic with respect to other list locked calls.
3006 * A buffer cannot be placed on two lists at the same time.
3008 void skb_append(struct sk_buff
*old
, struct sk_buff
*newsk
, struct sk_buff_head
*list
)
3010 unsigned long flags
;
3012 spin_lock_irqsave(&list
->lock
, flags
);
3013 __skb_queue_after(list
, old
, newsk
);
3014 spin_unlock_irqrestore(&list
->lock
, flags
);
3016 EXPORT_SYMBOL(skb_append
);
3018 static inline void skb_split_inside_header(struct sk_buff
*skb
,
3019 struct sk_buff
* skb1
,
3020 const u32 len
, const int pos
)
3024 skb_copy_from_linear_data_offset(skb
, len
, skb_put(skb1
, pos
- len
),
3026 /* And move data appendix as is. */
3027 for (i
= 0; i
< skb_shinfo(skb
)->nr_frags
; i
++)
3028 skb_shinfo(skb1
)->frags
[i
] = skb_shinfo(skb
)->frags
[i
];
3030 skb_shinfo(skb1
)->nr_frags
= skb_shinfo(skb
)->nr_frags
;
3031 skb_shinfo(skb
)->nr_frags
= 0;
3032 skb1
->data_len
= skb
->data_len
;
3033 skb1
->len
+= skb1
->data_len
;
3036 skb_set_tail_pointer(skb
, len
);
3039 static inline void skb_split_no_header(struct sk_buff
*skb
,
3040 struct sk_buff
* skb1
,
3041 const u32 len
, int pos
)
3044 const int nfrags
= skb_shinfo(skb
)->nr_frags
;
3046 skb_shinfo(skb
)->nr_frags
= 0;
3047 skb1
->len
= skb1
->data_len
= skb
->len
- len
;
3049 skb
->data_len
= len
- pos
;
3051 for (i
= 0; i
< nfrags
; i
++) {
3052 int size
= skb_frag_size(&skb_shinfo(skb
)->frags
[i
]);
3054 if (pos
+ size
> len
) {
3055 skb_shinfo(skb1
)->frags
[k
] = skb_shinfo(skb
)->frags
[i
];
3059 * We have two variants in this case:
3060 * 1. Move all the frag to the second
3061 * part, if it is possible. F.e.
3062 * this approach is mandatory for TUX,
3063 * where splitting is expensive.
3064 * 2. Split is accurately. We make this.
3066 skb_frag_ref(skb
, i
);
3067 skb_shinfo(skb1
)->frags
[0].page_offset
+= len
- pos
;
3068 skb_frag_size_sub(&skb_shinfo(skb1
)->frags
[0], len
- pos
);
3069 skb_frag_size_set(&skb_shinfo(skb
)->frags
[i
], len
- pos
);
3070 skb_shinfo(skb
)->nr_frags
++;
3074 skb_shinfo(skb
)->nr_frags
++;
3077 skb_shinfo(skb1
)->nr_frags
= k
;
3081 * skb_split - Split fragmented skb to two parts at length len.
3082 * @skb: the buffer to split
3083 * @skb1: the buffer to receive the second part
3084 * @len: new length for skb
3086 void skb_split(struct sk_buff
*skb
, struct sk_buff
*skb1
, const u32 len
)
3088 int pos
= skb_headlen(skb
);
3090 skb_shinfo(skb1
)->tx_flags
|= skb_shinfo(skb
)->tx_flags
&
3092 skb_zerocopy_clone(skb1
, skb
, 0);
3093 if (len
< pos
) /* Split line is inside header. */
3094 skb_split_inside_header(skb
, skb1
, len
, pos
);
3095 else /* Second chunk has no header, nothing to copy. */
3096 skb_split_no_header(skb
, skb1
, len
, pos
);
3098 EXPORT_SYMBOL(skb_split
);
3100 /* Shifting from/to a cloned skb is a no-go.
3102 * Caller cannot keep skb_shinfo related pointers past calling here!
3104 static int skb_prepare_for_shift(struct sk_buff
*skb
)
3106 return skb_cloned(skb
) && pskb_expand_head(skb
, 0, 0, GFP_ATOMIC
);
3110 * skb_shift - Shifts paged data partially from skb to another
3111 * @tgt: buffer into which tail data gets added
3112 * @skb: buffer from which the paged data comes from
3113 * @shiftlen: shift up to this many bytes
3115 * Attempts to shift up to shiftlen worth of bytes, which may be less than
3116 * the length of the skb, from skb to tgt. Returns number bytes shifted.
3117 * It's up to caller to free skb if everything was shifted.
3119 * If @tgt runs out of frags, the whole operation is aborted.
3121 * Skb cannot include anything else but paged data while tgt is allowed
3122 * to have non-paged data as well.
3124 * TODO: full sized shift could be optimized but that would need
3125 * specialized skb free'er to handle frags without up-to-date nr_frags.
3127 int skb_shift(struct sk_buff
*tgt
, struct sk_buff
*skb
, int shiftlen
)
3129 int from
, to
, merge
, todo
;
3130 struct skb_frag_struct
*fragfrom
, *fragto
;
3132 BUG_ON(shiftlen
> skb
->len
);
3134 if (skb_headlen(skb
))
3136 if (skb_zcopy(tgt
) || skb_zcopy(skb
))
3141 to
= skb_shinfo(tgt
)->nr_frags
;
3142 fragfrom
= &skb_shinfo(skb
)->frags
[from
];
3144 /* Actual merge is delayed until the point when we know we can
3145 * commit all, so that we don't have to undo partial changes
3148 !skb_can_coalesce(tgt
, to
, skb_frag_page(fragfrom
),
3149 fragfrom
->page_offset
)) {
3154 todo
-= skb_frag_size(fragfrom
);
3156 if (skb_prepare_for_shift(skb
) ||
3157 skb_prepare_for_shift(tgt
))
3160 /* All previous frag pointers might be stale! */
3161 fragfrom
= &skb_shinfo(skb
)->frags
[from
];
3162 fragto
= &skb_shinfo(tgt
)->frags
[merge
];
3164 skb_frag_size_add(fragto
, shiftlen
);
3165 skb_frag_size_sub(fragfrom
, shiftlen
);
3166 fragfrom
->page_offset
+= shiftlen
;
3174 /* Skip full, not-fitting skb to avoid expensive operations */
3175 if ((shiftlen
== skb
->len
) &&
3176 (skb_shinfo(skb
)->nr_frags
- from
) > (MAX_SKB_FRAGS
- to
))
3179 if (skb_prepare_for_shift(skb
) || skb_prepare_for_shift(tgt
))
3182 while ((todo
> 0) && (from
< skb_shinfo(skb
)->nr_frags
)) {
3183 if (to
== MAX_SKB_FRAGS
)
3186 fragfrom
= &skb_shinfo(skb
)->frags
[from
];
3187 fragto
= &skb_shinfo(tgt
)->frags
[to
];
3189 if (todo
>= skb_frag_size(fragfrom
)) {
3190 *fragto
= *fragfrom
;
3191 todo
-= skb_frag_size(fragfrom
);
3196 __skb_frag_ref(fragfrom
);
3197 fragto
->page
= fragfrom
->page
;
3198 fragto
->page_offset
= fragfrom
->page_offset
;
3199 skb_frag_size_set(fragto
, todo
);
3201 fragfrom
->page_offset
+= todo
;
3202 skb_frag_size_sub(fragfrom
, todo
);
3210 /* Ready to "commit" this state change to tgt */
3211 skb_shinfo(tgt
)->nr_frags
= to
;
3214 fragfrom
= &skb_shinfo(skb
)->frags
[0];
3215 fragto
= &skb_shinfo(tgt
)->frags
[merge
];
3217 skb_frag_size_add(fragto
, skb_frag_size(fragfrom
));
3218 __skb_frag_unref(fragfrom
);
3221 /* Reposition in the original skb */
3223 while (from
< skb_shinfo(skb
)->nr_frags
)
3224 skb_shinfo(skb
)->frags
[to
++] = skb_shinfo(skb
)->frags
[from
++];
3225 skb_shinfo(skb
)->nr_frags
= to
;
3227 BUG_ON(todo
> 0 && !skb_shinfo(skb
)->nr_frags
);
3230 /* Most likely the tgt won't ever need its checksum anymore, skb on
3231 * the other hand might need it if it needs to be resent
3233 tgt
->ip_summed
= CHECKSUM_PARTIAL
;
3234 skb
->ip_summed
= CHECKSUM_PARTIAL
;
3236 /* Yak, is it really working this way? Some helper please? */
3237 skb
->len
-= shiftlen
;
3238 skb
->data_len
-= shiftlen
;
3239 skb
->truesize
-= shiftlen
;
3240 tgt
->len
+= shiftlen
;
3241 tgt
->data_len
+= shiftlen
;
3242 tgt
->truesize
+= shiftlen
;
3248 * skb_prepare_seq_read - Prepare a sequential read of skb data
3249 * @skb: the buffer to read
3250 * @from: lower offset of data to be read
3251 * @to: upper offset of data to be read
3252 * @st: state variable
3254 * Initializes the specified state variable. Must be called before
3255 * invoking skb_seq_read() for the first time.
3257 void skb_prepare_seq_read(struct sk_buff
*skb
, unsigned int from
,
3258 unsigned int to
, struct skb_seq_state
*st
)
3260 st
->lower_offset
= from
;
3261 st
->upper_offset
= to
;
3262 st
->root_skb
= st
->cur_skb
= skb
;
3263 st
->frag_idx
= st
->stepped_offset
= 0;
3264 st
->frag_data
= NULL
;
3266 EXPORT_SYMBOL(skb_prepare_seq_read
);
3269 * skb_seq_read - Sequentially read skb data
3270 * @consumed: number of bytes consumed by the caller so far
3271 * @data: destination pointer for data to be returned
3272 * @st: state variable
3274 * Reads a block of skb data at @consumed relative to the
3275 * lower offset specified to skb_prepare_seq_read(). Assigns
3276 * the head of the data block to @data and returns the length
3277 * of the block or 0 if the end of the skb data or the upper
3278 * offset has been reached.
3280 * The caller is not required to consume all of the data
3281 * returned, i.e. @consumed is typically set to the number
3282 * of bytes already consumed and the next call to
3283 * skb_seq_read() will return the remaining part of the block.
3285 * Note 1: The size of each block of data returned can be arbitrary,
3286 * this limitation is the cost for zerocopy sequential
3287 * reads of potentially non linear data.
3289 * Note 2: Fragment lists within fragments are not implemented
3290 * at the moment, state->root_skb could be replaced with
3291 * a stack for this purpose.
3293 unsigned int skb_seq_read(unsigned int consumed
, const u8
**data
,
3294 struct skb_seq_state
*st
)
3296 unsigned int block_limit
, abs_offset
= consumed
+ st
->lower_offset
;
3299 if (unlikely(abs_offset
>= st
->upper_offset
)) {
3300 if (st
->frag_data
) {
3301 kunmap_atomic(st
->frag_data
);
3302 st
->frag_data
= NULL
;
3308 block_limit
= skb_headlen(st
->cur_skb
) + st
->stepped_offset
;
3310 if (abs_offset
< block_limit
&& !st
->frag_data
) {
3311 *data
= st
->cur_skb
->data
+ (abs_offset
- st
->stepped_offset
);
3312 return block_limit
- abs_offset
;
3315 if (st
->frag_idx
== 0 && !st
->frag_data
)
3316 st
->stepped_offset
+= skb_headlen(st
->cur_skb
);
3318 while (st
->frag_idx
< skb_shinfo(st
->cur_skb
)->nr_frags
) {
3319 frag
= &skb_shinfo(st
->cur_skb
)->frags
[st
->frag_idx
];
3320 block_limit
= skb_frag_size(frag
) + st
->stepped_offset
;
3322 if (abs_offset
< block_limit
) {
3324 st
->frag_data
= kmap_atomic(skb_frag_page(frag
));
3326 *data
= (u8
*) st
->frag_data
+ frag
->page_offset
+
3327 (abs_offset
- st
->stepped_offset
);
3329 return block_limit
- abs_offset
;
3332 if (st
->frag_data
) {
3333 kunmap_atomic(st
->frag_data
);
3334 st
->frag_data
= NULL
;
3338 st
->stepped_offset
+= skb_frag_size(frag
);
3341 if (st
->frag_data
) {
3342 kunmap_atomic(st
->frag_data
);
3343 st
->frag_data
= NULL
;
3346 if (st
->root_skb
== st
->cur_skb
&& skb_has_frag_list(st
->root_skb
)) {
3347 st
->cur_skb
= skb_shinfo(st
->root_skb
)->frag_list
;
3350 } else if (st
->cur_skb
->next
) {
3351 st
->cur_skb
= st
->cur_skb
->next
;
3358 EXPORT_SYMBOL(skb_seq_read
);
3361 * skb_abort_seq_read - Abort a sequential read of skb data
3362 * @st: state variable
3364 * Must be called if skb_seq_read() was not called until it
3367 void skb_abort_seq_read(struct skb_seq_state
*st
)
3370 kunmap_atomic(st
->frag_data
);
3372 EXPORT_SYMBOL(skb_abort_seq_read
);
3374 #define TS_SKB_CB(state) ((struct skb_seq_state *) &((state)->cb))
3376 static unsigned int skb_ts_get_next_block(unsigned int offset
, const u8
**text
,
3377 struct ts_config
*conf
,
3378 struct ts_state
*state
)
3380 return skb_seq_read(offset
, text
, TS_SKB_CB(state
));
3383 static void skb_ts_finish(struct ts_config
*conf
, struct ts_state
*state
)
3385 skb_abort_seq_read(TS_SKB_CB(state
));
3389 * skb_find_text - Find a text pattern in skb data
3390 * @skb: the buffer to look in
3391 * @from: search offset
3393 * @config: textsearch configuration
3395 * Finds a pattern in the skb data according to the specified
3396 * textsearch configuration. Use textsearch_next() to retrieve
3397 * subsequent occurrences of the pattern. Returns the offset
3398 * to the first occurrence or UINT_MAX if no match was found.
3400 unsigned int skb_find_text(struct sk_buff
*skb
, unsigned int from
,
3401 unsigned int to
, struct ts_config
*config
)
3403 struct ts_state state
;
3406 config
->get_next_block
= skb_ts_get_next_block
;
3407 config
->finish
= skb_ts_finish
;
3409 skb_prepare_seq_read(skb
, from
, to
, TS_SKB_CB(&state
));
3411 ret
= textsearch_find(config
, &state
);
3412 return (ret
<= to
- from
? ret
: UINT_MAX
);
3414 EXPORT_SYMBOL(skb_find_text
);
3416 int skb_append_pagefrags(struct sk_buff
*skb
, struct page
*page
,
3417 int offset
, size_t size
)
3419 int i
= skb_shinfo(skb
)->nr_frags
;
3421 if (skb_can_coalesce(skb
, i
, page
, offset
)) {
3422 skb_frag_size_add(&skb_shinfo(skb
)->frags
[i
- 1], size
);
3423 } else if (i
< MAX_SKB_FRAGS
) {
3425 skb_fill_page_desc(skb
, i
, page
, offset
, size
);
3432 EXPORT_SYMBOL_GPL(skb_append_pagefrags
);
3435 * skb_pull_rcsum - pull skb and update receive checksum
3436 * @skb: buffer to update
3437 * @len: length of data pulled
3439 * This function performs an skb_pull on the packet and updates
3440 * the CHECKSUM_COMPLETE checksum. It should be used on
3441 * receive path processing instead of skb_pull unless you know
3442 * that the checksum difference is zero (e.g., a valid IP header)
3443 * or you are setting ip_summed to CHECKSUM_NONE.
3445 void *skb_pull_rcsum(struct sk_buff
*skb
, unsigned int len
)
3447 unsigned char *data
= skb
->data
;
3449 BUG_ON(len
> skb
->len
);
3450 __skb_pull(skb
, len
);
3451 skb_postpull_rcsum(skb
, data
, len
);
3454 EXPORT_SYMBOL_GPL(skb_pull_rcsum
);
3456 static inline skb_frag_t
skb_head_frag_to_page_desc(struct sk_buff
*frag_skb
)
3458 skb_frag_t head_frag
;
3461 page
= virt_to_head_page(frag_skb
->head
);
3462 head_frag
.page
.p
= page
;
3463 head_frag
.page_offset
= frag_skb
->data
-
3464 (unsigned char *)page_address(page
);
3465 head_frag
.size
= skb_headlen(frag_skb
);
3470 * skb_segment - Perform protocol segmentation on skb.
3471 * @head_skb: buffer to segment
3472 * @features: features for the output path (see dev->features)
3474 * This function performs segmentation on the given skb. It returns
3475 * a pointer to the first in a list of new skbs for the segments.
3476 * In case of error it returns ERR_PTR(err).
3478 struct sk_buff
*skb_segment(struct sk_buff
*head_skb
,
3479 netdev_features_t features
)
3481 struct sk_buff
*segs
= NULL
;
3482 struct sk_buff
*tail
= NULL
;
3483 struct sk_buff
*list_skb
= skb_shinfo(head_skb
)->frag_list
;
3484 skb_frag_t
*frag
= skb_shinfo(head_skb
)->frags
;
3485 unsigned int mss
= skb_shinfo(head_skb
)->gso_size
;
3486 unsigned int doffset
= head_skb
->data
- skb_mac_header(head_skb
);
3487 struct sk_buff
*frag_skb
= head_skb
;
3488 unsigned int offset
= doffset
;
3489 unsigned int tnl_hlen
= skb_tnl_header_len(head_skb
);
3490 unsigned int partial_segs
= 0;
3491 unsigned int headroom
;
3492 unsigned int len
= head_skb
->len
;
3495 int nfrags
= skb_shinfo(head_skb
)->nr_frags
;
3501 __skb_push(head_skb
, doffset
);
3502 proto
= skb_network_protocol(head_skb
, &dummy
);
3503 if (unlikely(!proto
))
3504 return ERR_PTR(-EINVAL
);
3506 sg
= !!(features
& NETIF_F_SG
);
3507 csum
= !!can_checksum_protocol(features
, proto
);
3509 if (sg
&& csum
&& (mss
!= GSO_BY_FRAGS
)) {
3510 if (!(features
& NETIF_F_GSO_PARTIAL
)) {
3511 struct sk_buff
*iter
;
3512 unsigned int frag_len
;
3515 !net_gso_ok(features
, skb_shinfo(head_skb
)->gso_type
))
3518 /* If we get here then all the required
3519 * GSO features except frag_list are supported.
3520 * Try to split the SKB to multiple GSO SKBs
3521 * with no frag_list.
3522 * Currently we can do that only when the buffers don't
3523 * have a linear part and all the buffers except
3524 * the last are of the same length.
3526 frag_len
= list_skb
->len
;
3527 skb_walk_frags(head_skb
, iter
) {
3528 if (frag_len
!= iter
->len
&& iter
->next
)
3530 if (skb_headlen(iter
) && !iter
->head_frag
)
3536 if (len
!= frag_len
)
3540 /* GSO partial only requires that we trim off any excess that
3541 * doesn't fit into an MSS sized block, so take care of that
3544 partial_segs
= len
/ mss
;
3545 if (partial_segs
> 1)
3546 mss
*= partial_segs
;
3552 headroom
= skb_headroom(head_skb
);
3553 pos
= skb_headlen(head_skb
);
3556 struct sk_buff
*nskb
;
3557 skb_frag_t
*nskb_frag
;
3561 if (unlikely(mss
== GSO_BY_FRAGS
)) {
3562 len
= list_skb
->len
;
3564 len
= head_skb
->len
- offset
;
3569 hsize
= skb_headlen(head_skb
) - offset
;
3572 if (hsize
> len
|| !sg
)
3575 if (!hsize
&& i
>= nfrags
&& skb_headlen(list_skb
) &&
3576 (skb_headlen(list_skb
) == len
|| sg
)) {
3577 BUG_ON(skb_headlen(list_skb
) > len
);
3580 nfrags
= skb_shinfo(list_skb
)->nr_frags
;
3581 frag
= skb_shinfo(list_skb
)->frags
;
3582 frag_skb
= list_skb
;
3583 pos
+= skb_headlen(list_skb
);
3585 while (pos
< offset
+ len
) {
3586 BUG_ON(i
>= nfrags
);
3588 size
= skb_frag_size(frag
);
3589 if (pos
+ size
> offset
+ len
)
3597 nskb
= skb_clone(list_skb
, GFP_ATOMIC
);
3598 list_skb
= list_skb
->next
;
3600 if (unlikely(!nskb
))
3603 if (unlikely(pskb_trim(nskb
, len
))) {
3608 hsize
= skb_end_offset(nskb
);
3609 if (skb_cow_head(nskb
, doffset
+ headroom
)) {
3614 nskb
->truesize
+= skb_end_offset(nskb
) - hsize
;
3615 skb_release_head_state(nskb
);
3616 __skb_push(nskb
, doffset
);
3618 nskb
= __alloc_skb(hsize
+ doffset
+ headroom
,
3619 GFP_ATOMIC
, skb_alloc_rx_flag(head_skb
),
3622 if (unlikely(!nskb
))
3625 skb_reserve(nskb
, headroom
);
3626 __skb_put(nskb
, doffset
);
3635 __copy_skb_header(nskb
, head_skb
);
3637 skb_headers_offset_update(nskb
, skb_headroom(nskb
) - headroom
);
3638 skb_reset_mac_len(nskb
);
3640 skb_copy_from_linear_data_offset(head_skb
, -tnl_hlen
,
3641 nskb
->data
- tnl_hlen
,
3642 doffset
+ tnl_hlen
);
3644 if (nskb
->len
== len
+ doffset
)
3645 goto perform_csum_check
;
3648 if (!nskb
->remcsum_offload
)
3649 nskb
->ip_summed
= CHECKSUM_NONE
;
3650 SKB_GSO_CB(nskb
)->csum
=
3651 skb_copy_and_csum_bits(head_skb
, offset
,
3654 SKB_GSO_CB(nskb
)->csum_start
=
3655 skb_headroom(nskb
) + doffset
;
3659 nskb_frag
= skb_shinfo(nskb
)->frags
;
3661 skb_copy_from_linear_data_offset(head_skb
, offset
,
3662 skb_put(nskb
, hsize
), hsize
);
3664 skb_shinfo(nskb
)->tx_flags
|= skb_shinfo(head_skb
)->tx_flags
&
3667 if (skb_orphan_frags(frag_skb
, GFP_ATOMIC
) ||
3668 skb_zerocopy_clone(nskb
, frag_skb
, GFP_ATOMIC
))
3671 while (pos
< offset
+ len
) {
3674 nfrags
= skb_shinfo(list_skb
)->nr_frags
;
3675 frag
= skb_shinfo(list_skb
)->frags
;
3676 frag_skb
= list_skb
;
3677 if (!skb_headlen(list_skb
)) {
3680 BUG_ON(!list_skb
->head_frag
);
3682 /* to make room for head_frag. */
3686 if (skb_orphan_frags(frag_skb
, GFP_ATOMIC
) ||
3687 skb_zerocopy_clone(nskb
, frag_skb
,
3691 list_skb
= list_skb
->next
;
3694 if (unlikely(skb_shinfo(nskb
)->nr_frags
>=
3696 net_warn_ratelimited(
3697 "skb_segment: too many frags: %u %u\n",
3703 *nskb_frag
= (i
< 0) ? skb_head_frag_to_page_desc(frag_skb
) : *frag
;
3704 __skb_frag_ref(nskb_frag
);
3705 size
= skb_frag_size(nskb_frag
);
3708 nskb_frag
->page_offset
+= offset
- pos
;
3709 skb_frag_size_sub(nskb_frag
, offset
- pos
);
3712 skb_shinfo(nskb
)->nr_frags
++;
3714 if (pos
+ size
<= offset
+ len
) {
3719 skb_frag_size_sub(nskb_frag
, pos
+ size
- (offset
+ len
));
3727 nskb
->data_len
= len
- hsize
;
3728 nskb
->len
+= nskb
->data_len
;
3729 nskb
->truesize
+= nskb
->data_len
;
3733 if (skb_has_shared_frag(nskb
) &&
3734 __skb_linearize(nskb
))
3737 if (!nskb
->remcsum_offload
)
3738 nskb
->ip_summed
= CHECKSUM_NONE
;
3739 SKB_GSO_CB(nskb
)->csum
=
3740 skb_checksum(nskb
, doffset
,
3741 nskb
->len
- doffset
, 0);
3742 SKB_GSO_CB(nskb
)->csum_start
=
3743 skb_headroom(nskb
) + doffset
;
3745 } while ((offset
+= len
) < head_skb
->len
);
3747 /* Some callers want to get the end of the list.
3748 * Put it in segs->prev to avoid walking the list.
3749 * (see validate_xmit_skb_list() for example)
3754 struct sk_buff
*iter
;
3755 int type
= skb_shinfo(head_skb
)->gso_type
;
3756 unsigned short gso_size
= skb_shinfo(head_skb
)->gso_size
;
3758 /* Update type to add partial and then remove dodgy if set */
3759 type
|= (features
& NETIF_F_GSO_PARTIAL
) / NETIF_F_GSO_PARTIAL
* SKB_GSO_PARTIAL
;
3760 type
&= ~SKB_GSO_DODGY
;
3762 /* Update GSO info and prepare to start updating headers on
3763 * our way back down the stack of protocols.
3765 for (iter
= segs
; iter
; iter
= iter
->next
) {
3766 skb_shinfo(iter
)->gso_size
= gso_size
;
3767 skb_shinfo(iter
)->gso_segs
= partial_segs
;
3768 skb_shinfo(iter
)->gso_type
= type
;
3769 SKB_GSO_CB(iter
)->data_offset
= skb_headroom(iter
) + doffset
;
3772 if (tail
->len
- doffset
<= gso_size
)
3773 skb_shinfo(tail
)->gso_size
= 0;
3774 else if (tail
!= segs
)
3775 skb_shinfo(tail
)->gso_segs
= DIV_ROUND_UP(tail
->len
- doffset
, gso_size
);
3778 /* Following permits correct backpressure, for protocols
3779 * using skb_set_owner_w().
3780 * Idea is to tranfert ownership from head_skb to last segment.
3782 if (head_skb
->destructor
== sock_wfree
) {
3783 swap(tail
->truesize
, head_skb
->truesize
);
3784 swap(tail
->destructor
, head_skb
->destructor
);
3785 swap(tail
->sk
, head_skb
->sk
);
3790 kfree_skb_list(segs
);
3791 return ERR_PTR(err
);
3793 EXPORT_SYMBOL_GPL(skb_segment
);
3795 int skb_gro_receive(struct sk_buff
*p
, struct sk_buff
*skb
)
3797 struct skb_shared_info
*pinfo
, *skbinfo
= skb_shinfo(skb
);
3798 unsigned int offset
= skb_gro_offset(skb
);
3799 unsigned int headlen
= skb_headlen(skb
);
3800 unsigned int len
= skb_gro_len(skb
);
3801 unsigned int delta_truesize
;
3804 if (unlikely(p
->len
+ len
>= 65536))
3807 lp
= NAPI_GRO_CB(p
)->last
;
3808 pinfo
= skb_shinfo(lp
);
3810 if (headlen
<= offset
) {
3813 int i
= skbinfo
->nr_frags
;
3814 int nr_frags
= pinfo
->nr_frags
+ i
;
3816 if (nr_frags
> MAX_SKB_FRAGS
)
3820 pinfo
->nr_frags
= nr_frags
;
3821 skbinfo
->nr_frags
= 0;
3823 frag
= pinfo
->frags
+ nr_frags
;
3824 frag2
= skbinfo
->frags
+ i
;
3829 frag
->page_offset
+= offset
;
3830 skb_frag_size_sub(frag
, offset
);
3832 /* all fragments truesize : remove (head size + sk_buff) */
3833 delta_truesize
= skb
->truesize
-
3834 SKB_TRUESIZE(skb_end_offset(skb
));
3836 skb
->truesize
-= skb
->data_len
;
3837 skb
->len
-= skb
->data_len
;
3840 NAPI_GRO_CB(skb
)->free
= NAPI_GRO_FREE
;
3842 } else if (skb
->head_frag
) {
3843 int nr_frags
= pinfo
->nr_frags
;
3844 skb_frag_t
*frag
= pinfo
->frags
+ nr_frags
;
3845 struct page
*page
= virt_to_head_page(skb
->head
);
3846 unsigned int first_size
= headlen
- offset
;
3847 unsigned int first_offset
;
3849 if (nr_frags
+ 1 + skbinfo
->nr_frags
> MAX_SKB_FRAGS
)
3852 first_offset
= skb
->data
-
3853 (unsigned char *)page_address(page
) +
3856 pinfo
->nr_frags
= nr_frags
+ 1 + skbinfo
->nr_frags
;
3858 frag
->page
.p
= page
;
3859 frag
->page_offset
= first_offset
;
3860 skb_frag_size_set(frag
, first_size
);
3862 memcpy(frag
+ 1, skbinfo
->frags
, sizeof(*frag
) * skbinfo
->nr_frags
);
3863 /* We dont need to clear skbinfo->nr_frags here */
3865 delta_truesize
= skb
->truesize
- SKB_DATA_ALIGN(sizeof(struct sk_buff
));
3866 NAPI_GRO_CB(skb
)->free
= NAPI_GRO_FREE_STOLEN_HEAD
;
3871 delta_truesize
= skb
->truesize
;
3872 if (offset
> headlen
) {
3873 unsigned int eat
= offset
- headlen
;
3875 skbinfo
->frags
[0].page_offset
+= eat
;
3876 skb_frag_size_sub(&skbinfo
->frags
[0], eat
);
3877 skb
->data_len
-= eat
;
3882 __skb_pull(skb
, offset
);
3884 if (NAPI_GRO_CB(p
)->last
== p
)
3885 skb_shinfo(p
)->frag_list
= skb
;
3887 NAPI_GRO_CB(p
)->last
->next
= skb
;
3888 NAPI_GRO_CB(p
)->last
= skb
;
3889 __skb_header_release(skb
);
3893 NAPI_GRO_CB(p
)->count
++;
3895 p
->truesize
+= delta_truesize
;
3898 lp
->data_len
+= len
;
3899 lp
->truesize
+= delta_truesize
;
3902 NAPI_GRO_CB(skb
)->same_flow
= 1;
3905 EXPORT_SYMBOL_GPL(skb_gro_receive
);
3907 #ifdef CONFIG_SKB_EXTENSIONS
3908 #define SKB_EXT_ALIGN_VALUE 8
3909 #define SKB_EXT_CHUNKSIZEOF(x) (ALIGN((sizeof(x)), SKB_EXT_ALIGN_VALUE) / SKB_EXT_ALIGN_VALUE)
3911 static const u8 skb_ext_type_len
[] = {
3912 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
3913 [SKB_EXT_BRIDGE_NF
] = SKB_EXT_CHUNKSIZEOF(struct nf_bridge_info
),
3916 [SKB_EXT_SEC_PATH
] = SKB_EXT_CHUNKSIZEOF(struct sec_path
),
3920 static __always_inline
unsigned int skb_ext_total_length(void)
3922 return SKB_EXT_CHUNKSIZEOF(struct skb_ext
) +
3923 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
3924 skb_ext_type_len
[SKB_EXT_BRIDGE_NF
] +
3927 skb_ext_type_len
[SKB_EXT_SEC_PATH
] +
3932 static void skb_extensions_init(void)
3934 BUILD_BUG_ON(SKB_EXT_NUM
>= 8);
3935 BUILD_BUG_ON(skb_ext_total_length() > 255);
3937 skbuff_ext_cache
= kmem_cache_create("skbuff_ext_cache",
3938 SKB_EXT_ALIGN_VALUE
* skb_ext_total_length(),
3940 SLAB_HWCACHE_ALIGN
|SLAB_PANIC
,
3944 static void skb_extensions_init(void) {}
3947 void __init
skb_init(void)
3949 skbuff_head_cache
= kmem_cache_create_usercopy("skbuff_head_cache",
3950 sizeof(struct sk_buff
),
3952 SLAB_HWCACHE_ALIGN
|SLAB_PANIC
,
3953 offsetof(struct sk_buff
, cb
),
3954 sizeof_field(struct sk_buff
, cb
),
3956 skbuff_fclone_cache
= kmem_cache_create("skbuff_fclone_cache",
3957 sizeof(struct sk_buff_fclones
),
3959 SLAB_HWCACHE_ALIGN
|SLAB_PANIC
,
3961 skb_extensions_init();
3965 __skb_to_sgvec(struct sk_buff
*skb
, struct scatterlist
*sg
, int offset
, int len
,
3966 unsigned int recursion_level
)
3968 int start
= skb_headlen(skb
);
3969 int i
, copy
= start
- offset
;
3970 struct sk_buff
*frag_iter
;
3973 if (unlikely(recursion_level
>= 24))
3979 sg_set_buf(sg
, skb
->data
+ offset
, copy
);
3981 if ((len
-= copy
) == 0)
3986 for (i
= 0; i
< skb_shinfo(skb
)->nr_frags
; i
++) {
3989 WARN_ON(start
> offset
+ len
);
3991 end
= start
+ skb_frag_size(&skb_shinfo(skb
)->frags
[i
]);
3992 if ((copy
= end
- offset
) > 0) {
3993 skb_frag_t
*frag
= &skb_shinfo(skb
)->frags
[i
];
3994 if (unlikely(elt
&& sg_is_last(&sg
[elt
- 1])))
3999 sg_set_page(&sg
[elt
], skb_frag_page(frag
), copy
,
4000 frag
->page_offset
+offset
-start
);
4009 skb_walk_frags(skb
, frag_iter
) {
4012 WARN_ON(start
> offset
+ len
);
4014 end
= start
+ frag_iter
->len
;
4015 if ((copy
= end
- offset
) > 0) {
4016 if (unlikely(elt
&& sg_is_last(&sg
[elt
- 1])))
4021 ret
= __skb_to_sgvec(frag_iter
, sg
+elt
, offset
- start
,
4022 copy
, recursion_level
+ 1);
4023 if (unlikely(ret
< 0))
4026 if ((len
-= copy
) == 0)
4037 * skb_to_sgvec - Fill a scatter-gather list from a socket buffer
4038 * @skb: Socket buffer containing the buffers to be mapped
4039 * @sg: The scatter-gather list to map into
4040 * @offset: The offset into the buffer's contents to start mapping
4041 * @len: Length of buffer space to be mapped
4043 * Fill the specified scatter-gather list with mappings/pointers into a
4044 * region of the buffer space attached to a socket buffer. Returns either
4045 * the number of scatterlist items used, or -EMSGSIZE if the contents
4048 int skb_to_sgvec(struct sk_buff
*skb
, struct scatterlist
*sg
, int offset
, int len
)
4050 int nsg
= __skb_to_sgvec(skb
, sg
, offset
, len
, 0);
4055 sg_mark_end(&sg
[nsg
- 1]);
4059 EXPORT_SYMBOL_GPL(skb_to_sgvec
);
4061 /* As compared with skb_to_sgvec, skb_to_sgvec_nomark only map skb to given
4062 * sglist without mark the sg which contain last skb data as the end.
4063 * So the caller can mannipulate sg list as will when padding new data after
4064 * the first call without calling sg_unmark_end to expend sg list.
4066 * Scenario to use skb_to_sgvec_nomark:
4068 * 2. skb_to_sgvec_nomark(payload1)
4069 * 3. skb_to_sgvec_nomark(payload2)
4071 * This is equivalent to:
4073 * 2. skb_to_sgvec(payload1)
4075 * 4. skb_to_sgvec(payload2)
4077 * When mapping mutilple payload conditionally, skb_to_sgvec_nomark
4078 * is more preferable.
4080 int skb_to_sgvec_nomark(struct sk_buff
*skb
, struct scatterlist
*sg
,
4081 int offset
, int len
)
4083 return __skb_to_sgvec(skb
, sg
, offset
, len
, 0);
4085 EXPORT_SYMBOL_GPL(skb_to_sgvec_nomark
);
4090 * skb_cow_data - Check that a socket buffer's data buffers are writable
4091 * @skb: The socket buffer to check.
4092 * @tailbits: Amount of trailing space to be added
4093 * @trailer: Returned pointer to the skb where the @tailbits space begins
4095 * Make sure that the data buffers attached to a socket buffer are
4096 * writable. If they are not, private copies are made of the data buffers
4097 * and the socket buffer is set to use these instead.
4099 * If @tailbits is given, make sure that there is space to write @tailbits
4100 * bytes of data beyond current end of socket buffer. @trailer will be
4101 * set to point to the skb in which this space begins.
4103 * The number of scatterlist elements required to completely map the
4104 * COW'd and extended socket buffer will be returned.
4106 int skb_cow_data(struct sk_buff
*skb
, int tailbits
, struct sk_buff
**trailer
)
4110 struct sk_buff
*skb1
, **skb_p
;
4112 /* If skb is cloned or its head is paged, reallocate
4113 * head pulling out all the pages (pages are considered not writable
4114 * at the moment even if they are anonymous).
4116 if ((skb_cloned(skb
) || skb_shinfo(skb
)->nr_frags
) &&
4117 __pskb_pull_tail(skb
, skb_pagelen(skb
)-skb_headlen(skb
)) == NULL
)
4120 /* Easy case. Most of packets will go this way. */
4121 if (!skb_has_frag_list(skb
)) {
4122 /* A little of trouble, not enough of space for trailer.
4123 * This should not happen, when stack is tuned to generate
4124 * good frames. OK, on miss we reallocate and reserve even more
4125 * space, 128 bytes is fair. */
4127 if (skb_tailroom(skb
) < tailbits
&&
4128 pskb_expand_head(skb
, 0, tailbits
-skb_tailroom(skb
)+128, GFP_ATOMIC
))
4136 /* Misery. We are in troubles, going to mincer fragments... */
4139 skb_p
= &skb_shinfo(skb
)->frag_list
;
4142 while ((skb1
= *skb_p
) != NULL
) {
4145 /* The fragment is partially pulled by someone,
4146 * this can happen on input. Copy it and everything
4149 if (skb_shared(skb1
))
4152 /* If the skb is the last, worry about trailer. */
4154 if (skb1
->next
== NULL
&& tailbits
) {
4155 if (skb_shinfo(skb1
)->nr_frags
||
4156 skb_has_frag_list(skb1
) ||
4157 skb_tailroom(skb1
) < tailbits
)
4158 ntail
= tailbits
+ 128;
4164 skb_shinfo(skb1
)->nr_frags
||
4165 skb_has_frag_list(skb1
)) {
4166 struct sk_buff
*skb2
;
4168 /* Fuck, we are miserable poor guys... */
4170 skb2
= skb_copy(skb1
, GFP_ATOMIC
);
4172 skb2
= skb_copy_expand(skb1
,
4176 if (unlikely(skb2
== NULL
))
4180 skb_set_owner_w(skb2
, skb1
->sk
);
4182 /* Looking around. Are we still alive?
4183 * OK, link new skb, drop old one */
4185 skb2
->next
= skb1
->next
;
4192 skb_p
= &skb1
->next
;
4197 EXPORT_SYMBOL_GPL(skb_cow_data
);
4199 static void sock_rmem_free(struct sk_buff
*skb
)
4201 struct sock
*sk
= skb
->sk
;
4203 atomic_sub(skb
->truesize
, &sk
->sk_rmem_alloc
);
4206 static void skb_set_err_queue(struct sk_buff
*skb
)
4208 /* pkt_type of skbs received on local sockets is never PACKET_OUTGOING.
4209 * So, it is safe to (mis)use it to mark skbs on the error queue.
4211 skb
->pkt_type
= PACKET_OUTGOING
;
4212 BUILD_BUG_ON(PACKET_OUTGOING
== 0);
4216 * Note: We dont mem charge error packets (no sk_forward_alloc changes)
4218 int sock_queue_err_skb(struct sock
*sk
, struct sk_buff
*skb
)
4220 if (atomic_read(&sk
->sk_rmem_alloc
) + skb
->truesize
>=
4221 (unsigned int)sk
->sk_rcvbuf
)
4226 skb
->destructor
= sock_rmem_free
;
4227 atomic_add(skb
->truesize
, &sk
->sk_rmem_alloc
);
4228 skb_set_err_queue(skb
);
4230 /* before exiting rcu section, make sure dst is refcounted */
4233 skb_queue_tail(&sk
->sk_error_queue
, skb
);
4234 if (!sock_flag(sk
, SOCK_DEAD
))
4235 sk
->sk_error_report(sk
);
4238 EXPORT_SYMBOL(sock_queue_err_skb
);
4240 static bool is_icmp_err_skb(const struct sk_buff
*skb
)
4242 return skb
&& (SKB_EXT_ERR(skb
)->ee
.ee_origin
== SO_EE_ORIGIN_ICMP
||
4243 SKB_EXT_ERR(skb
)->ee
.ee_origin
== SO_EE_ORIGIN_ICMP6
);
4246 struct sk_buff
*sock_dequeue_err_skb(struct sock
*sk
)
4248 struct sk_buff_head
*q
= &sk
->sk_error_queue
;
4249 struct sk_buff
*skb
, *skb_next
= NULL
;
4250 bool icmp_next
= false;
4251 unsigned long flags
;
4253 spin_lock_irqsave(&q
->lock
, flags
);
4254 skb
= __skb_dequeue(q
);
4255 if (skb
&& (skb_next
= skb_peek(q
))) {
4256 icmp_next
= is_icmp_err_skb(skb_next
);
4258 sk
->sk_err
= SKB_EXT_ERR(skb_next
)->ee
.ee_origin
;
4260 spin_unlock_irqrestore(&q
->lock
, flags
);
4262 if (is_icmp_err_skb(skb
) && !icmp_next
)
4266 sk
->sk_error_report(sk
);
4270 EXPORT_SYMBOL(sock_dequeue_err_skb
);
4273 * skb_clone_sk - create clone of skb, and take reference to socket
4274 * @skb: the skb to clone
4276 * This function creates a clone of a buffer that holds a reference on
4277 * sk_refcnt. Buffers created via this function are meant to be
4278 * returned using sock_queue_err_skb, or free via kfree_skb.
4280 * When passing buffers allocated with this function to sock_queue_err_skb
4281 * it is necessary to wrap the call with sock_hold/sock_put in order to
4282 * prevent the socket from being released prior to being enqueued on
4283 * the sk_error_queue.
4285 struct sk_buff
*skb_clone_sk(struct sk_buff
*skb
)
4287 struct sock
*sk
= skb
->sk
;
4288 struct sk_buff
*clone
;
4290 if (!sk
|| !refcount_inc_not_zero(&sk
->sk_refcnt
))
4293 clone
= skb_clone(skb
, GFP_ATOMIC
);
4300 clone
->destructor
= sock_efree
;
4304 EXPORT_SYMBOL(skb_clone_sk
);
4306 static void __skb_complete_tx_timestamp(struct sk_buff
*skb
,
4311 struct sock_exterr_skb
*serr
;
4314 BUILD_BUG_ON(sizeof(struct sock_exterr_skb
) > sizeof(skb
->cb
));
4316 serr
= SKB_EXT_ERR(skb
);
4317 memset(serr
, 0, sizeof(*serr
));
4318 serr
->ee
.ee_errno
= ENOMSG
;
4319 serr
->ee
.ee_origin
= SO_EE_ORIGIN_TIMESTAMPING
;
4320 serr
->ee
.ee_info
= tstype
;
4321 serr
->opt_stats
= opt_stats
;
4322 serr
->header
.h4
.iif
= skb
->dev
? skb
->dev
->ifindex
: 0;
4323 if (sk
->sk_tsflags
& SOF_TIMESTAMPING_OPT_ID
) {
4324 serr
->ee
.ee_data
= skb_shinfo(skb
)->tskey
;
4325 if (sk
->sk_protocol
== IPPROTO_TCP
&&
4326 sk
->sk_type
== SOCK_STREAM
)
4327 serr
->ee
.ee_data
-= sk
->sk_tskey
;
4330 err
= sock_queue_err_skb(sk
, skb
);
4336 static bool skb_may_tx_timestamp(struct sock
*sk
, bool tsonly
)
4340 if (likely(sysctl_tstamp_allow_data
|| tsonly
))
4343 read_lock_bh(&sk
->sk_callback_lock
);
4344 ret
= sk
->sk_socket
&& sk
->sk_socket
->file
&&
4345 file_ns_capable(sk
->sk_socket
->file
, &init_user_ns
, CAP_NET_RAW
);
4346 read_unlock_bh(&sk
->sk_callback_lock
);
4350 void skb_complete_tx_timestamp(struct sk_buff
*skb
,
4351 struct skb_shared_hwtstamps
*hwtstamps
)
4353 struct sock
*sk
= skb
->sk
;
4355 if (!skb_may_tx_timestamp(sk
, false))
4358 /* Take a reference to prevent skb_orphan() from freeing the socket,
4359 * but only if the socket refcount is not zero.
4361 if (likely(refcount_inc_not_zero(&sk
->sk_refcnt
))) {
4362 *skb_hwtstamps(skb
) = *hwtstamps
;
4363 __skb_complete_tx_timestamp(skb
, sk
, SCM_TSTAMP_SND
, false);
4371 EXPORT_SYMBOL_GPL(skb_complete_tx_timestamp
);
4373 void __skb_tstamp_tx(struct sk_buff
*orig_skb
,
4374 struct skb_shared_hwtstamps
*hwtstamps
,
4375 struct sock
*sk
, int tstype
)
4377 struct sk_buff
*skb
;
4378 bool tsonly
, opt_stats
= false;
4383 if (!hwtstamps
&& !(sk
->sk_tsflags
& SOF_TIMESTAMPING_OPT_TX_SWHW
) &&
4384 skb_shinfo(orig_skb
)->tx_flags
& SKBTX_IN_PROGRESS
)
4387 tsonly
= sk
->sk_tsflags
& SOF_TIMESTAMPING_OPT_TSONLY
;
4388 if (!skb_may_tx_timestamp(sk
, tsonly
))
4393 if ((sk
->sk_tsflags
& SOF_TIMESTAMPING_OPT_STATS
) &&
4394 sk
->sk_protocol
== IPPROTO_TCP
&&
4395 sk
->sk_type
== SOCK_STREAM
) {
4396 skb
= tcp_get_timestamping_opt_stats(sk
);
4400 skb
= alloc_skb(0, GFP_ATOMIC
);
4402 skb
= skb_clone(orig_skb
, GFP_ATOMIC
);
4408 skb_shinfo(skb
)->tx_flags
|= skb_shinfo(orig_skb
)->tx_flags
&
4410 skb_shinfo(skb
)->tskey
= skb_shinfo(orig_skb
)->tskey
;
4414 *skb_hwtstamps(skb
) = *hwtstamps
;
4416 skb
->tstamp
= ktime_get_real();
4418 __skb_complete_tx_timestamp(skb
, sk
, tstype
, opt_stats
);
4420 EXPORT_SYMBOL_GPL(__skb_tstamp_tx
);
4422 void skb_tstamp_tx(struct sk_buff
*orig_skb
,
4423 struct skb_shared_hwtstamps
*hwtstamps
)
4425 return __skb_tstamp_tx(orig_skb
, hwtstamps
, orig_skb
->sk
,
4428 EXPORT_SYMBOL_GPL(skb_tstamp_tx
);
4430 void skb_complete_wifi_ack(struct sk_buff
*skb
, bool acked
)
4432 struct sock
*sk
= skb
->sk
;
4433 struct sock_exterr_skb
*serr
;
4436 skb
->wifi_acked_valid
= 1;
4437 skb
->wifi_acked
= acked
;
4439 serr
= SKB_EXT_ERR(skb
);
4440 memset(serr
, 0, sizeof(*serr
));
4441 serr
->ee
.ee_errno
= ENOMSG
;
4442 serr
->ee
.ee_origin
= SO_EE_ORIGIN_TXSTATUS
;
4444 /* Take a reference to prevent skb_orphan() from freeing the socket,
4445 * but only if the socket refcount is not zero.
4447 if (likely(refcount_inc_not_zero(&sk
->sk_refcnt
))) {
4448 err
= sock_queue_err_skb(sk
, skb
);
4454 EXPORT_SYMBOL_GPL(skb_complete_wifi_ack
);
4457 * skb_partial_csum_set - set up and verify partial csum values for packet
4458 * @skb: the skb to set
4459 * @start: the number of bytes after skb->data to start checksumming.
4460 * @off: the offset from start to place the checksum.
4462 * For untrusted partially-checksummed packets, we need to make sure the values
4463 * for skb->csum_start and skb->csum_offset are valid so we don't oops.
4465 * This function checks and sets those values and skb->ip_summed: if this
4466 * returns false you should drop the packet.
4468 bool skb_partial_csum_set(struct sk_buff
*skb
, u16 start
, u16 off
)
4470 u32 csum_end
= (u32
)start
+ (u32
)off
+ sizeof(__sum16
);
4471 u32 csum_start
= skb_headroom(skb
) + (u32
)start
;
4473 if (unlikely(csum_start
> U16_MAX
|| csum_end
> skb_headlen(skb
))) {
4474 net_warn_ratelimited("bad partial csum: csum=%u/%u headroom=%u headlen=%u\n",
4475 start
, off
, skb_headroom(skb
), skb_headlen(skb
));
4478 skb
->ip_summed
= CHECKSUM_PARTIAL
;
4479 skb
->csum_start
= csum_start
;
4480 skb
->csum_offset
= off
;
4481 skb_set_transport_header(skb
, start
);
4484 EXPORT_SYMBOL_GPL(skb_partial_csum_set
);
4486 static int skb_maybe_pull_tail(struct sk_buff
*skb
, unsigned int len
,
4489 if (skb_headlen(skb
) >= len
)
4492 /* If we need to pullup then pullup to the max, so we
4493 * won't need to do it again.
4498 if (__pskb_pull_tail(skb
, max
- skb_headlen(skb
)) == NULL
)
4501 if (skb_headlen(skb
) < len
)
4507 #define MAX_TCP_HDR_LEN (15 * 4)
4509 static __sum16
*skb_checksum_setup_ip(struct sk_buff
*skb
,
4510 typeof(IPPROTO_IP
) proto
,
4517 err
= skb_maybe_pull_tail(skb
, off
+ sizeof(struct tcphdr
),
4518 off
+ MAX_TCP_HDR_LEN
);
4519 if (!err
&& !skb_partial_csum_set(skb
, off
,
4520 offsetof(struct tcphdr
,
4523 return err
? ERR_PTR(err
) : &tcp_hdr(skb
)->check
;
4526 err
= skb_maybe_pull_tail(skb
, off
+ sizeof(struct udphdr
),
4527 off
+ sizeof(struct udphdr
));
4528 if (!err
&& !skb_partial_csum_set(skb
, off
,
4529 offsetof(struct udphdr
,
4532 return err
? ERR_PTR(err
) : &udp_hdr(skb
)->check
;
4535 return ERR_PTR(-EPROTO
);
4538 /* This value should be large enough to cover a tagged ethernet header plus
4539 * maximally sized IP and TCP or UDP headers.
4541 #define MAX_IP_HDR_LEN 128
4543 static int skb_checksum_setup_ipv4(struct sk_buff
*skb
, bool recalculate
)
4552 err
= skb_maybe_pull_tail(skb
,
4553 sizeof(struct iphdr
),
4558 if (ip_hdr(skb
)->frag_off
& htons(IP_OFFSET
| IP_MF
))
4561 off
= ip_hdrlen(skb
);
4568 csum
= skb_checksum_setup_ip(skb
, ip_hdr(skb
)->protocol
, off
);
4570 return PTR_ERR(csum
);
4573 *csum
= ~csum_tcpudp_magic(ip_hdr(skb
)->saddr
,
4576 ip_hdr(skb
)->protocol
, 0);
4583 /* This value should be large enough to cover a tagged ethernet header plus
4584 * an IPv6 header, all options, and a maximal TCP or UDP header.
4586 #define MAX_IPV6_HDR_LEN 256
4588 #define OPT_HDR(type, skb, off) \
4589 (type *)(skb_network_header(skb) + (off))
4591 static int skb_checksum_setup_ipv6(struct sk_buff
*skb
, bool recalculate
)
4604 off
= sizeof(struct ipv6hdr
);
4606 err
= skb_maybe_pull_tail(skb
, off
, MAX_IPV6_HDR_LEN
);
4610 nexthdr
= ipv6_hdr(skb
)->nexthdr
;
4612 len
= sizeof(struct ipv6hdr
) + ntohs(ipv6_hdr(skb
)->payload_len
);
4613 while (off
<= len
&& !done
) {
4615 case IPPROTO_DSTOPTS
:
4616 case IPPROTO_HOPOPTS
:
4617 case IPPROTO_ROUTING
: {
4618 struct ipv6_opt_hdr
*hp
;
4620 err
= skb_maybe_pull_tail(skb
,
4622 sizeof(struct ipv6_opt_hdr
),
4627 hp
= OPT_HDR(struct ipv6_opt_hdr
, skb
, off
);
4628 nexthdr
= hp
->nexthdr
;
4629 off
+= ipv6_optlen(hp
);
4633 struct ip_auth_hdr
*hp
;
4635 err
= skb_maybe_pull_tail(skb
,
4637 sizeof(struct ip_auth_hdr
),
4642 hp
= OPT_HDR(struct ip_auth_hdr
, skb
, off
);
4643 nexthdr
= hp
->nexthdr
;
4644 off
+= ipv6_authlen(hp
);
4647 case IPPROTO_FRAGMENT
: {
4648 struct frag_hdr
*hp
;
4650 err
= skb_maybe_pull_tail(skb
,
4652 sizeof(struct frag_hdr
),
4657 hp
= OPT_HDR(struct frag_hdr
, skb
, off
);
4659 if (hp
->frag_off
& htons(IP6_OFFSET
| IP6_MF
))
4662 nexthdr
= hp
->nexthdr
;
4663 off
+= sizeof(struct frag_hdr
);
4674 if (!done
|| fragment
)
4677 csum
= skb_checksum_setup_ip(skb
, nexthdr
, off
);
4679 return PTR_ERR(csum
);
4682 *csum
= ~csum_ipv6_magic(&ipv6_hdr(skb
)->saddr
,
4683 &ipv6_hdr(skb
)->daddr
,
4684 skb
->len
- off
, nexthdr
, 0);
4692 * skb_checksum_setup - set up partial checksum offset
4693 * @skb: the skb to set up
4694 * @recalculate: if true the pseudo-header checksum will be recalculated
4696 int skb_checksum_setup(struct sk_buff
*skb
, bool recalculate
)
4700 switch (skb
->protocol
) {
4701 case htons(ETH_P_IP
):
4702 err
= skb_checksum_setup_ipv4(skb
, recalculate
);
4705 case htons(ETH_P_IPV6
):
4706 err
= skb_checksum_setup_ipv6(skb
, recalculate
);
4716 EXPORT_SYMBOL(skb_checksum_setup
);
4719 * skb_checksum_maybe_trim - maybe trims the given skb
4720 * @skb: the skb to check
4721 * @transport_len: the data length beyond the network header
4723 * Checks whether the given skb has data beyond the given transport length.
4724 * If so, returns a cloned skb trimmed to this transport length.
4725 * Otherwise returns the provided skb. Returns NULL in error cases
4726 * (e.g. transport_len exceeds skb length or out-of-memory).
4728 * Caller needs to set the skb transport header and free any returned skb if it
4729 * differs from the provided skb.
4731 static struct sk_buff
*skb_checksum_maybe_trim(struct sk_buff
*skb
,
4732 unsigned int transport_len
)
4734 struct sk_buff
*skb_chk
;
4735 unsigned int len
= skb_transport_offset(skb
) + transport_len
;
4740 else if (skb
->len
== len
)
4743 skb_chk
= skb_clone(skb
, GFP_ATOMIC
);
4747 ret
= pskb_trim_rcsum(skb_chk
, len
);
4757 * skb_checksum_trimmed - validate checksum of an skb
4758 * @skb: the skb to check
4759 * @transport_len: the data length beyond the network header
4760 * @skb_chkf: checksum function to use
4762 * Applies the given checksum function skb_chkf to the provided skb.
4763 * Returns a checked and maybe trimmed skb. Returns NULL on error.
4765 * If the skb has data beyond the given transport length, then a
4766 * trimmed & cloned skb is checked and returned.
4768 * Caller needs to set the skb transport header and free any returned skb if it
4769 * differs from the provided skb.
4771 struct sk_buff
*skb_checksum_trimmed(struct sk_buff
*skb
,
4772 unsigned int transport_len
,
4773 __sum16(*skb_chkf
)(struct sk_buff
*skb
))
4775 struct sk_buff
*skb_chk
;
4776 unsigned int offset
= skb_transport_offset(skb
);
4779 skb_chk
= skb_checksum_maybe_trim(skb
, transport_len
);
4783 if (!pskb_may_pull(skb_chk
, offset
))
4786 skb_pull_rcsum(skb_chk
, offset
);
4787 ret
= skb_chkf(skb_chk
);
4788 skb_push_rcsum(skb_chk
, offset
);
4796 if (skb_chk
&& skb_chk
!= skb
)
4802 EXPORT_SYMBOL(skb_checksum_trimmed
);
4804 void __skb_warn_lro_forwarding(const struct sk_buff
*skb
)
4806 net_warn_ratelimited("%s: received packets cannot be forwarded while LRO is enabled\n",
4809 EXPORT_SYMBOL(__skb_warn_lro_forwarding
);
4811 void kfree_skb_partial(struct sk_buff
*skb
, bool head_stolen
)
4814 skb_release_head_state(skb
);
4815 kmem_cache_free(skbuff_head_cache
, skb
);
4820 EXPORT_SYMBOL(kfree_skb_partial
);
4823 * skb_try_coalesce - try to merge skb to prior one
4825 * @from: buffer to add
4826 * @fragstolen: pointer to boolean
4827 * @delta_truesize: how much more was allocated than was requested
4829 bool skb_try_coalesce(struct sk_buff
*to
, struct sk_buff
*from
,
4830 bool *fragstolen
, int *delta_truesize
)
4832 struct skb_shared_info
*to_shinfo
, *from_shinfo
;
4833 int i
, delta
, len
= from
->len
;
4835 *fragstolen
= false;
4840 if (len
<= skb_tailroom(to
)) {
4842 BUG_ON(skb_copy_bits(from
, 0, skb_put(to
, len
), len
));
4843 *delta_truesize
= 0;
4847 to_shinfo
= skb_shinfo(to
);
4848 from_shinfo
= skb_shinfo(from
);
4849 if (to_shinfo
->frag_list
|| from_shinfo
->frag_list
)
4851 if (skb_zcopy(to
) || skb_zcopy(from
))
4854 if (skb_headlen(from
) != 0) {
4856 unsigned int offset
;
4858 if (to_shinfo
->nr_frags
+
4859 from_shinfo
->nr_frags
>= MAX_SKB_FRAGS
)
4862 if (skb_head_is_locked(from
))
4865 delta
= from
->truesize
- SKB_DATA_ALIGN(sizeof(struct sk_buff
));
4867 page
= virt_to_head_page(from
->head
);
4868 offset
= from
->data
- (unsigned char *)page_address(page
);
4870 skb_fill_page_desc(to
, to_shinfo
->nr_frags
,
4871 page
, offset
, skb_headlen(from
));
4874 if (to_shinfo
->nr_frags
+
4875 from_shinfo
->nr_frags
> MAX_SKB_FRAGS
)
4878 delta
= from
->truesize
- SKB_TRUESIZE(skb_end_offset(from
));
4881 WARN_ON_ONCE(delta
< len
);
4883 memcpy(to_shinfo
->frags
+ to_shinfo
->nr_frags
,
4885 from_shinfo
->nr_frags
* sizeof(skb_frag_t
));
4886 to_shinfo
->nr_frags
+= from_shinfo
->nr_frags
;
4888 if (!skb_cloned(from
))
4889 from_shinfo
->nr_frags
= 0;
4891 /* if the skb is not cloned this does nothing
4892 * since we set nr_frags to 0.
4894 for (i
= 0; i
< from_shinfo
->nr_frags
; i
++)
4895 __skb_frag_ref(&from_shinfo
->frags
[i
]);
4897 to
->truesize
+= delta
;
4899 to
->data_len
+= len
;
4901 *delta_truesize
= delta
;
4904 EXPORT_SYMBOL(skb_try_coalesce
);
4907 * skb_scrub_packet - scrub an skb
4909 * @skb: buffer to clean
4910 * @xnet: packet is crossing netns
4912 * skb_scrub_packet can be used after encapsulating or decapsulting a packet
4913 * into/from a tunnel. Some information have to be cleared during these
4915 * skb_scrub_packet can also be used to clean a skb before injecting it in
4916 * another namespace (@xnet == true). We have to clear all information in the
4917 * skb that could impact namespace isolation.
4919 void skb_scrub_packet(struct sk_buff
*skb
, bool xnet
)
4921 skb
->pkt_type
= PACKET_HOST
;
4927 nf_reset_trace(skb
);
4929 #ifdef CONFIG_NET_SWITCHDEV
4930 skb
->offload_fwd_mark
= 0;
4931 skb
->offload_l3_fwd_mark
= 0;
4941 EXPORT_SYMBOL_GPL(skb_scrub_packet
);
4944 * skb_gso_transport_seglen - Return length of individual segments of a gso packet
4948 * skb_gso_transport_seglen is used to determine the real size of the
4949 * individual segments, including Layer4 headers (TCP/UDP).
4951 * The MAC/L2 or network (IP, IPv6) headers are not accounted for.
4953 static unsigned int skb_gso_transport_seglen(const struct sk_buff
*skb
)
4955 const struct skb_shared_info
*shinfo
= skb_shinfo(skb
);
4956 unsigned int thlen
= 0;
4958 if (skb
->encapsulation
) {
4959 thlen
= skb_inner_transport_header(skb
) -
4960 skb_transport_header(skb
);
4962 if (likely(shinfo
->gso_type
& (SKB_GSO_TCPV4
| SKB_GSO_TCPV6
)))
4963 thlen
+= inner_tcp_hdrlen(skb
);
4964 } else if (likely(shinfo
->gso_type
& (SKB_GSO_TCPV4
| SKB_GSO_TCPV6
))) {
4965 thlen
= tcp_hdrlen(skb
);
4966 } else if (unlikely(skb_is_gso_sctp(skb
))) {
4967 thlen
= sizeof(struct sctphdr
);
4968 } else if (shinfo
->gso_type
& SKB_GSO_UDP_L4
) {
4969 thlen
= sizeof(struct udphdr
);
4971 /* UFO sets gso_size to the size of the fragmentation
4972 * payload, i.e. the size of the L4 (UDP) header is already
4975 return thlen
+ shinfo
->gso_size
;
4979 * skb_gso_network_seglen - Return length of individual segments of a gso packet
4983 * skb_gso_network_seglen is used to determine the real size of the
4984 * individual segments, including Layer3 (IP, IPv6) and L4 headers (TCP/UDP).
4986 * The MAC/L2 header is not accounted for.
4988 static unsigned int skb_gso_network_seglen(const struct sk_buff
*skb
)
4990 unsigned int hdr_len
= skb_transport_header(skb
) -
4991 skb_network_header(skb
);
4993 return hdr_len
+ skb_gso_transport_seglen(skb
);
4997 * skb_gso_mac_seglen - Return length of individual segments of a gso packet
5001 * skb_gso_mac_seglen is used to determine the real size of the
5002 * individual segments, including MAC/L2, Layer3 (IP, IPv6) and L4
5003 * headers (TCP/UDP).
5005 static unsigned int skb_gso_mac_seglen(const struct sk_buff
*skb
)
5007 unsigned int hdr_len
= skb_transport_header(skb
) - skb_mac_header(skb
);
5009 return hdr_len
+ skb_gso_transport_seglen(skb
);
5013 * skb_gso_size_check - check the skb size, considering GSO_BY_FRAGS
5015 * There are a couple of instances where we have a GSO skb, and we
5016 * want to determine what size it would be after it is segmented.
5018 * We might want to check:
5019 * - L3+L4+payload size (e.g. IP forwarding)
5020 * - L2+L3+L4+payload size (e.g. sanity check before passing to driver)
5022 * This is a helper to do that correctly considering GSO_BY_FRAGS.
5026 * @seg_len: The segmented length (from skb_gso_*_seglen). In the
5027 * GSO_BY_FRAGS case this will be [header sizes + GSO_BY_FRAGS].
5029 * @max_len: The maximum permissible length.
5031 * Returns true if the segmented length <= max length.
5033 static inline bool skb_gso_size_check(const struct sk_buff
*skb
,
5034 unsigned int seg_len
,
5035 unsigned int max_len
) {
5036 const struct skb_shared_info
*shinfo
= skb_shinfo(skb
);
5037 const struct sk_buff
*iter
;
5039 if (shinfo
->gso_size
!= GSO_BY_FRAGS
)
5040 return seg_len
<= max_len
;
5042 /* Undo this so we can re-use header sizes */
5043 seg_len
-= GSO_BY_FRAGS
;
5045 skb_walk_frags(skb
, iter
) {
5046 if (seg_len
+ skb_headlen(iter
) > max_len
)
5054 * skb_gso_validate_network_len - Will a split GSO skb fit into a given MTU?
5057 * @mtu: MTU to validate against
5059 * skb_gso_validate_network_len validates if a given skb will fit a
5060 * wanted MTU once split. It considers L3 headers, L4 headers, and the
5063 bool skb_gso_validate_network_len(const struct sk_buff
*skb
, unsigned int mtu
)
5065 return skb_gso_size_check(skb
, skb_gso_network_seglen(skb
), mtu
);
5067 EXPORT_SYMBOL_GPL(skb_gso_validate_network_len
);
5070 * skb_gso_validate_mac_len - Will a split GSO skb fit in a given length?
5073 * @len: length to validate against
5075 * skb_gso_validate_mac_len validates if a given skb will fit a wanted
5076 * length once split, including L2, L3 and L4 headers and the payload.
5078 bool skb_gso_validate_mac_len(const struct sk_buff
*skb
, unsigned int len
)
5080 return skb_gso_size_check(skb
, skb_gso_mac_seglen(skb
), len
);
5082 EXPORT_SYMBOL_GPL(skb_gso_validate_mac_len
);
5084 static struct sk_buff
*skb_reorder_vlan_header(struct sk_buff
*skb
)
5088 if (skb_cow(skb
, skb_headroom(skb
)) < 0) {
5093 mac_len
= skb
->data
- skb_mac_header(skb
);
5094 if (likely(mac_len
> VLAN_HLEN
+ ETH_TLEN
)) {
5095 memmove(skb_mac_header(skb
) + VLAN_HLEN
, skb_mac_header(skb
),
5096 mac_len
- VLAN_HLEN
- ETH_TLEN
);
5098 skb
->mac_header
+= VLAN_HLEN
;
5102 struct sk_buff
*skb_vlan_untag(struct sk_buff
*skb
)
5104 struct vlan_hdr
*vhdr
;
5107 if (unlikely(skb_vlan_tag_present(skb
))) {
5108 /* vlan_tci is already set-up so leave this for another time */
5112 skb
= skb_share_check(skb
, GFP_ATOMIC
);
5116 if (unlikely(!pskb_may_pull(skb
, VLAN_HLEN
)))
5119 vhdr
= (struct vlan_hdr
*)skb
->data
;
5120 vlan_tci
= ntohs(vhdr
->h_vlan_TCI
);
5121 __vlan_hwaccel_put_tag(skb
, skb
->protocol
, vlan_tci
);
5123 skb_pull_rcsum(skb
, VLAN_HLEN
);
5124 vlan_set_encap_proto(skb
, vhdr
);
5126 skb
= skb_reorder_vlan_header(skb
);
5130 skb_reset_network_header(skb
);
5131 skb_reset_transport_header(skb
);
5132 skb_reset_mac_len(skb
);
5140 EXPORT_SYMBOL(skb_vlan_untag
);
5142 int skb_ensure_writable(struct sk_buff
*skb
, int write_len
)
5144 if (!pskb_may_pull(skb
, write_len
))
5147 if (!skb_cloned(skb
) || skb_clone_writable(skb
, write_len
))
5150 return pskb_expand_head(skb
, 0, 0, GFP_ATOMIC
);
5152 EXPORT_SYMBOL(skb_ensure_writable
);
5154 /* remove VLAN header from packet and update csum accordingly.
5155 * expects a non skb_vlan_tag_present skb with a vlan tag payload
5157 int __skb_vlan_pop(struct sk_buff
*skb
, u16
*vlan_tci
)
5159 struct vlan_hdr
*vhdr
;
5160 int offset
= skb
->data
- skb_mac_header(skb
);
5163 if (WARN_ONCE(offset
,
5164 "__skb_vlan_pop got skb with skb->data not at mac header (offset %d)\n",
5169 err
= skb_ensure_writable(skb
, VLAN_ETH_HLEN
);
5173 skb_postpull_rcsum(skb
, skb
->data
+ (2 * ETH_ALEN
), VLAN_HLEN
);
5175 vhdr
= (struct vlan_hdr
*)(skb
->data
+ ETH_HLEN
);
5176 *vlan_tci
= ntohs(vhdr
->h_vlan_TCI
);
5178 memmove(skb
->data
+ VLAN_HLEN
, skb
->data
, 2 * ETH_ALEN
);
5179 __skb_pull(skb
, VLAN_HLEN
);
5181 vlan_set_encap_proto(skb
, vhdr
);
5182 skb
->mac_header
+= VLAN_HLEN
;
5184 if (skb_network_offset(skb
) < ETH_HLEN
)
5185 skb_set_network_header(skb
, ETH_HLEN
);
5187 skb_reset_mac_len(skb
);
5191 EXPORT_SYMBOL(__skb_vlan_pop
);
5193 /* Pop a vlan tag either from hwaccel or from payload.
5194 * Expects skb->data at mac header.
5196 int skb_vlan_pop(struct sk_buff
*skb
)
5202 if (likely(skb_vlan_tag_present(skb
))) {
5203 __vlan_hwaccel_clear_tag(skb
);
5205 if (unlikely(!eth_type_vlan(skb
->protocol
)))
5208 err
= __skb_vlan_pop(skb
, &vlan_tci
);
5212 /* move next vlan tag to hw accel tag */
5213 if (likely(!eth_type_vlan(skb
->protocol
)))
5216 vlan_proto
= skb
->protocol
;
5217 err
= __skb_vlan_pop(skb
, &vlan_tci
);
5221 __vlan_hwaccel_put_tag(skb
, vlan_proto
, vlan_tci
);
5224 EXPORT_SYMBOL(skb_vlan_pop
);
5226 /* Push a vlan tag either into hwaccel or into payload (if hwaccel tag present).
5227 * Expects skb->data at mac header.
5229 int skb_vlan_push(struct sk_buff
*skb
, __be16 vlan_proto
, u16 vlan_tci
)
5231 if (skb_vlan_tag_present(skb
)) {
5232 int offset
= skb
->data
- skb_mac_header(skb
);
5235 if (WARN_ONCE(offset
,
5236 "skb_vlan_push got skb with skb->data not at mac header (offset %d)\n",
5241 err
= __vlan_insert_tag(skb
, skb
->vlan_proto
,
5242 skb_vlan_tag_get(skb
));
5246 skb
->protocol
= skb
->vlan_proto
;
5247 skb
->mac_len
+= VLAN_HLEN
;
5249 skb_postpush_rcsum(skb
, skb
->data
+ (2 * ETH_ALEN
), VLAN_HLEN
);
5251 __vlan_hwaccel_put_tag(skb
, vlan_proto
, vlan_tci
);
5254 EXPORT_SYMBOL(skb_vlan_push
);
5257 * alloc_skb_with_frags - allocate skb with page frags
5259 * @header_len: size of linear part
5260 * @data_len: needed length in frags
5261 * @max_page_order: max page order desired.
5262 * @errcode: pointer to error code if any
5263 * @gfp_mask: allocation mask
5265 * This can be used to allocate a paged skb, given a maximal order for frags.
5267 struct sk_buff
*alloc_skb_with_frags(unsigned long header_len
,
5268 unsigned long data_len
,
5273 int npages
= (data_len
+ (PAGE_SIZE
- 1)) >> PAGE_SHIFT
;
5274 unsigned long chunk
;
5275 struct sk_buff
*skb
;
5279 *errcode
= -EMSGSIZE
;
5280 /* Note this test could be relaxed, if we succeed to allocate
5281 * high order pages...
5283 if (npages
> MAX_SKB_FRAGS
)
5286 *errcode
= -ENOBUFS
;
5287 skb
= alloc_skb(header_len
, gfp_mask
);
5291 skb
->truesize
+= npages
<< PAGE_SHIFT
;
5293 for (i
= 0; npages
> 0; i
++) {
5294 int order
= max_page_order
;
5297 if (npages
>= 1 << order
) {
5298 page
= alloc_pages((gfp_mask
& ~__GFP_DIRECT_RECLAIM
) |
5304 /* Do not retry other high order allocations */
5310 page
= alloc_page(gfp_mask
);
5314 chunk
= min_t(unsigned long, data_len
,
5315 PAGE_SIZE
<< order
);
5316 skb_fill_page_desc(skb
, i
, page
, 0, chunk
);
5318 npages
-= 1 << order
;
5326 EXPORT_SYMBOL(alloc_skb_with_frags
);
5328 /* carve out the first off bytes from skb when off < headlen */
5329 static int pskb_carve_inside_header(struct sk_buff
*skb
, const u32 off
,
5330 const int headlen
, gfp_t gfp_mask
)
5333 int size
= skb_end_offset(skb
);
5334 int new_hlen
= headlen
- off
;
5337 size
= SKB_DATA_ALIGN(size
);
5339 if (skb_pfmemalloc(skb
))
5340 gfp_mask
|= __GFP_MEMALLOC
;
5341 data
= kmalloc_reserve(size
+
5342 SKB_DATA_ALIGN(sizeof(struct skb_shared_info
)),
5343 gfp_mask
, NUMA_NO_NODE
, NULL
);
5347 size
= SKB_WITH_OVERHEAD(ksize(data
));
5349 /* Copy real data, and all frags */
5350 skb_copy_from_linear_data_offset(skb
, off
, data
, new_hlen
);
5353 memcpy((struct skb_shared_info
*)(data
+ size
),
5355 offsetof(struct skb_shared_info
,
5356 frags
[skb_shinfo(skb
)->nr_frags
]));
5357 if (skb_cloned(skb
)) {
5358 /* drop the old head gracefully */
5359 if (skb_orphan_frags(skb
, gfp_mask
)) {
5363 for (i
= 0; i
< skb_shinfo(skb
)->nr_frags
; i
++)
5364 skb_frag_ref(skb
, i
);
5365 if (skb_has_frag_list(skb
))
5366 skb_clone_fraglist(skb
);
5367 skb_release_data(skb
);
5369 /* we can reuse existing recount- all we did was
5378 #ifdef NET_SKBUFF_DATA_USES_OFFSET
5381 skb
->end
= skb
->head
+ size
;
5383 skb_set_tail_pointer(skb
, skb_headlen(skb
));
5384 skb_headers_offset_update(skb
, 0);
5388 atomic_set(&skb_shinfo(skb
)->dataref
, 1);
5393 static int pskb_carve(struct sk_buff
*skb
, const u32 off
, gfp_t gfp
);
5395 /* carve out the first eat bytes from skb's frag_list. May recurse into
5398 static int pskb_carve_frag_list(struct sk_buff
*skb
,
5399 struct skb_shared_info
*shinfo
, int eat
,
5402 struct sk_buff
*list
= shinfo
->frag_list
;
5403 struct sk_buff
*clone
= NULL
;
5404 struct sk_buff
*insp
= NULL
;
5408 pr_err("Not enough bytes to eat. Want %d\n", eat
);
5411 if (list
->len
<= eat
) {
5412 /* Eaten as whole. */
5417 /* Eaten partially. */
5418 if (skb_shared(list
)) {
5419 clone
= skb_clone(list
, gfp_mask
);
5425 /* This may be pulled without problems. */
5428 if (pskb_carve(list
, eat
, gfp_mask
) < 0) {
5436 /* Free pulled out fragments. */
5437 while ((list
= shinfo
->frag_list
) != insp
) {
5438 shinfo
->frag_list
= list
->next
;
5441 /* And insert new clone at head. */
5444 shinfo
->frag_list
= clone
;
5449 /* carve off first len bytes from skb. Split line (off) is in the
5450 * non-linear part of skb
5452 static int pskb_carve_inside_nonlinear(struct sk_buff
*skb
, const u32 off
,
5453 int pos
, gfp_t gfp_mask
)
5456 int size
= skb_end_offset(skb
);
5458 const int nfrags
= skb_shinfo(skb
)->nr_frags
;
5459 struct skb_shared_info
*shinfo
;
5461 size
= SKB_DATA_ALIGN(size
);
5463 if (skb_pfmemalloc(skb
))
5464 gfp_mask
|= __GFP_MEMALLOC
;
5465 data
= kmalloc_reserve(size
+
5466 SKB_DATA_ALIGN(sizeof(struct skb_shared_info
)),
5467 gfp_mask
, NUMA_NO_NODE
, NULL
);
5471 size
= SKB_WITH_OVERHEAD(ksize(data
));
5473 memcpy((struct skb_shared_info
*)(data
+ size
),
5474 skb_shinfo(skb
), offsetof(struct skb_shared_info
,
5475 frags
[skb_shinfo(skb
)->nr_frags
]));
5476 if (skb_orphan_frags(skb
, gfp_mask
)) {
5480 shinfo
= (struct skb_shared_info
*)(data
+ size
);
5481 for (i
= 0; i
< nfrags
; i
++) {
5482 int fsize
= skb_frag_size(&skb_shinfo(skb
)->frags
[i
]);
5484 if (pos
+ fsize
> off
) {
5485 shinfo
->frags
[k
] = skb_shinfo(skb
)->frags
[i
];
5489 * We have two variants in this case:
5490 * 1. Move all the frag to the second
5491 * part, if it is possible. F.e.
5492 * this approach is mandatory for TUX,
5493 * where splitting is expensive.
5494 * 2. Split is accurately. We make this.
5496 shinfo
->frags
[0].page_offset
+= off
- pos
;
5497 skb_frag_size_sub(&shinfo
->frags
[0], off
- pos
);
5499 skb_frag_ref(skb
, i
);
5504 shinfo
->nr_frags
= k
;
5505 if (skb_has_frag_list(skb
))
5506 skb_clone_fraglist(skb
);
5509 /* split line is in frag list */
5510 pskb_carve_frag_list(skb
, shinfo
, off
- pos
, gfp_mask
);
5512 skb_release_data(skb
);
5517 #ifdef NET_SKBUFF_DATA_USES_OFFSET
5520 skb
->end
= skb
->head
+ size
;
5522 skb_reset_tail_pointer(skb
);
5523 skb_headers_offset_update(skb
, 0);
5528 skb
->data_len
= skb
->len
;
5529 atomic_set(&skb_shinfo(skb
)->dataref
, 1);
5533 /* remove len bytes from the beginning of the skb */
5534 static int pskb_carve(struct sk_buff
*skb
, const u32 len
, gfp_t gfp
)
5536 int headlen
= skb_headlen(skb
);
5539 return pskb_carve_inside_header(skb
, len
, headlen
, gfp
);
5541 return pskb_carve_inside_nonlinear(skb
, len
, headlen
, gfp
);
5544 /* Extract to_copy bytes starting at off from skb, and return this in
5547 struct sk_buff
*pskb_extract(struct sk_buff
*skb
, int off
,
5548 int to_copy
, gfp_t gfp
)
5550 struct sk_buff
*clone
= skb_clone(skb
, gfp
);
5555 if (pskb_carve(clone
, off
, gfp
) < 0 ||
5556 pskb_trim(clone
, to_copy
)) {
5562 EXPORT_SYMBOL(pskb_extract
);
5565 * skb_condense - try to get rid of fragments/frag_list if possible
5568 * Can be used to save memory before skb is added to a busy queue.
5569 * If packet has bytes in frags and enough tail room in skb->head,
5570 * pull all of them, so that we can free the frags right now and adjust
5573 * We do not reallocate skb->head thus can not fail.
5574 * Caller must re-evaluate skb->truesize if needed.
5576 void skb_condense(struct sk_buff
*skb
)
5578 if (skb
->data_len
) {
5579 if (skb
->data_len
> skb
->end
- skb
->tail
||
5583 /* Nice, we can free page frag(s) right now */
5584 __pskb_pull_tail(skb
, skb
->data_len
);
5586 /* At this point, skb->truesize might be over estimated,
5587 * because skb had a fragment, and fragments do not tell
5589 * When we pulled its content into skb->head, fragment
5590 * was freed, but __pskb_pull_tail() could not possibly
5591 * adjust skb->truesize, not knowing the frag truesize.
5593 skb
->truesize
= SKB_TRUESIZE(skb_end_offset(skb
));
5596 #ifdef CONFIG_SKB_EXTENSIONS
5597 static void *skb_ext_get_ptr(struct skb_ext
*ext
, enum skb_ext_id id
)
5599 return (void *)ext
+ (ext
->offset
[id
] * SKB_EXT_ALIGN_VALUE
);
5602 static struct skb_ext
*skb_ext_alloc(void)
5604 struct skb_ext
*new = kmem_cache_alloc(skbuff_ext_cache
, GFP_ATOMIC
);
5607 memset(new->offset
, 0, sizeof(new->offset
));
5608 refcount_set(&new->refcnt
, 1);
5614 static struct skb_ext
*skb_ext_maybe_cow(struct skb_ext
*old
,
5615 unsigned int old_active
)
5617 struct skb_ext
*new;
5619 if (refcount_read(&old
->refcnt
) == 1)
5622 new = kmem_cache_alloc(skbuff_ext_cache
, GFP_ATOMIC
);
5626 memcpy(new, old
, old
->chunks
* SKB_EXT_ALIGN_VALUE
);
5627 refcount_set(&new->refcnt
, 1);
5630 if (old_active
& (1 << SKB_EXT_SEC_PATH
)) {
5631 struct sec_path
*sp
= skb_ext_get_ptr(old
, SKB_EXT_SEC_PATH
);
5634 for (i
= 0; i
< sp
->len
; i
++)
5635 xfrm_state_hold(sp
->xvec
[i
]);
5643 * skb_ext_add - allocate space for given extension, COW if needed
5645 * @id: extension to allocate space for
5647 * Allocates enough space for the given extension.
5648 * If the extension is already present, a pointer to that extension
5651 * If the skb was cloned, COW applies and the returned memory can be
5652 * modified without changing the extension space of clones buffers.
5654 * Returns pointer to the extension or NULL on allocation failure.
5656 void *skb_ext_add(struct sk_buff
*skb
, enum skb_ext_id id
)
5658 struct skb_ext
*new, *old
= NULL
;
5659 unsigned int newlen
, newoff
;
5661 if (skb
->active_extensions
) {
5662 old
= skb
->extensions
;
5664 new = skb_ext_maybe_cow(old
, skb
->active_extensions
);
5668 if (__skb_ext_exist(new, id
))
5671 newoff
= new->chunks
;
5673 newoff
= SKB_EXT_CHUNKSIZEOF(*new);
5675 new = skb_ext_alloc();
5680 newlen
= newoff
+ skb_ext_type_len
[id
];
5681 new->chunks
= newlen
;
5682 new->offset
[id
] = newoff
;
5684 skb
->extensions
= new;
5685 skb
->active_extensions
|= 1 << id
;
5686 return skb_ext_get_ptr(new, id
);
5688 EXPORT_SYMBOL(skb_ext_add
);
5691 static void skb_ext_put_sp(struct sec_path
*sp
)
5695 for (i
= 0; i
< sp
->len
; i
++)
5696 xfrm_state_put(sp
->xvec
[i
]);
5700 void __skb_ext_del(struct sk_buff
*skb
, enum skb_ext_id id
)
5702 struct skb_ext
*ext
= skb
->extensions
;
5704 skb
->active_extensions
&= ~(1 << id
);
5705 if (skb
->active_extensions
== 0) {
5706 skb
->extensions
= NULL
;
5709 } else if (id
== SKB_EXT_SEC_PATH
&&
5710 refcount_read(&ext
->refcnt
) == 1) {
5711 struct sec_path
*sp
= skb_ext_get_ptr(ext
, SKB_EXT_SEC_PATH
);
5718 EXPORT_SYMBOL(__skb_ext_del
);
5720 void __skb_ext_put(struct skb_ext
*ext
)
5722 /* If this is last clone, nothing can increment
5723 * it after check passes. Avoids one atomic op.
5725 if (refcount_read(&ext
->refcnt
) == 1)
5728 if (!refcount_dec_and_test(&ext
->refcnt
))
5732 if (__skb_ext_exist(ext
, SKB_EXT_SEC_PATH
))
5733 skb_ext_put_sp(skb_ext_get_ptr(ext
, SKB_EXT_SEC_PATH
));
5736 kmem_cache_free(skbuff_ext_cache
, ext
);
5738 EXPORT_SYMBOL(__skb_ext_put
);
5739 #endif /* CONFIG_SKB_EXTENSIONS */