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>
44 #include <linux/kmemcheck.h>
46 #include <linux/interrupt.h>
48 #include <linux/inet.h>
49 #include <linux/slab.h>
50 #include <linux/tcp.h>
51 #include <linux/udp.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 <asm/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 __read_mostly
;
81 static struct kmem_cache
*skbuff_fclone_cache __read_mostly
;
82 int sysctl_max_skb_frags __read_mostly
= MAX_SKB_FRAGS
;
83 EXPORT_SYMBOL(sysctl_max_skb_frags
);
86 * skb_panic - private function for out-of-line support
90 * @msg: skb_over_panic or skb_under_panic
92 * Out-of-line support for skb_put() and skb_push().
93 * Called via the wrapper skb_over_panic() or skb_under_panic().
94 * Keep out of line to prevent kernel bloat.
95 * __builtin_return_address is not used because it is not always reliable.
97 static void skb_panic(struct sk_buff
*skb
, unsigned int sz
, void *addr
,
100 pr_emerg("%s: text:%p len:%d put:%d head:%p data:%p tail:%#lx end:%#lx dev:%s\n",
101 msg
, addr
, skb
->len
, sz
, skb
->head
, skb
->data
,
102 (unsigned long)skb
->tail
, (unsigned long)skb
->end
,
103 skb
->dev
? skb
->dev
->name
: "<NULL>");
107 static void skb_over_panic(struct sk_buff
*skb
, unsigned int sz
, void *addr
)
109 skb_panic(skb
, sz
, addr
, __func__
);
112 static void skb_under_panic(struct sk_buff
*skb
, unsigned int sz
, void *addr
)
114 skb_panic(skb
, sz
, addr
, __func__
);
118 * kmalloc_reserve is a wrapper around kmalloc_node_track_caller that tells
119 * the caller if emergency pfmemalloc reserves are being used. If it is and
120 * the socket is later found to be SOCK_MEMALLOC then PFMEMALLOC reserves
121 * may be used. Otherwise, the packet data may be discarded until enough
124 #define kmalloc_reserve(size, gfp, node, pfmemalloc) \
125 __kmalloc_reserve(size, gfp, node, _RET_IP_, pfmemalloc)
127 static void *__kmalloc_reserve(size_t size
, gfp_t flags
, int node
,
128 unsigned long ip
, bool *pfmemalloc
)
131 bool ret_pfmemalloc
= false;
134 * Try a regular allocation, when that fails and we're not entitled
135 * to the reserves, fail.
137 obj
= kmalloc_node_track_caller(size
,
138 flags
| __GFP_NOMEMALLOC
| __GFP_NOWARN
,
140 if (obj
|| !(gfp_pfmemalloc_allowed(flags
)))
143 /* Try again but now we are using pfmemalloc reserves */
144 ret_pfmemalloc
= true;
145 obj
= kmalloc_node_track_caller(size
, flags
, node
);
149 *pfmemalloc
= ret_pfmemalloc
;
154 /* Allocate a new skbuff. We do this ourselves so we can fill in a few
155 * 'private' fields and also do memory statistics to find all the
160 struct sk_buff
*__alloc_skb_head(gfp_t gfp_mask
, int node
)
165 skb
= kmem_cache_alloc_node(skbuff_head_cache
,
166 gfp_mask
& ~__GFP_DMA
, node
);
171 * Only clear those fields we need to clear, not those that we will
172 * actually initialise below. Hence, don't put any more fields after
173 * the tail pointer in struct sk_buff!
175 memset(skb
, 0, offsetof(struct sk_buff
, tail
));
177 skb
->truesize
= sizeof(struct sk_buff
);
178 atomic_set(&skb
->users
, 1);
180 skb
->mac_header
= (typeof(skb
->mac_header
))~0U;
186 * __alloc_skb - allocate a network buffer
187 * @size: size to allocate
188 * @gfp_mask: allocation mask
189 * @flags: If SKB_ALLOC_FCLONE is set, allocate from fclone cache
190 * instead of head cache and allocate a cloned (child) skb.
191 * If SKB_ALLOC_RX is set, __GFP_MEMALLOC will be used for
192 * allocations in case the data is required for writeback
193 * @node: numa node to allocate memory on
195 * Allocate a new &sk_buff. The returned buffer has no headroom and a
196 * tail room of at least size bytes. The object has a reference count
197 * of one. The return is the buffer. On a failure the return is %NULL.
199 * Buffers may only be allocated from interrupts using a @gfp_mask of
202 struct sk_buff
*__alloc_skb(unsigned int size
, gfp_t gfp_mask
,
205 struct kmem_cache
*cache
;
206 struct skb_shared_info
*shinfo
;
211 cache
= (flags
& SKB_ALLOC_FCLONE
)
212 ? skbuff_fclone_cache
: skbuff_head_cache
;
214 if (sk_memalloc_socks() && (flags
& SKB_ALLOC_RX
))
215 gfp_mask
|= __GFP_MEMALLOC
;
218 skb
= kmem_cache_alloc_node(cache
, gfp_mask
& ~__GFP_DMA
, node
);
223 /* We do our best to align skb_shared_info on a separate cache
224 * line. It usually works because kmalloc(X > SMP_CACHE_BYTES) gives
225 * aligned memory blocks, unless SLUB/SLAB debug is enabled.
226 * Both skb->head and skb_shared_info are cache line aligned.
228 size
= SKB_DATA_ALIGN(size
);
229 size
+= SKB_DATA_ALIGN(sizeof(struct skb_shared_info
));
230 data
= kmalloc_reserve(size
, gfp_mask
, node
, &pfmemalloc
);
233 /* kmalloc(size) might give us more room than requested.
234 * Put skb_shared_info exactly at the end of allocated zone,
235 * to allow max possible filling before reallocation.
237 size
= SKB_WITH_OVERHEAD(ksize(data
));
238 prefetchw(data
+ size
);
241 * Only clear those fields we need to clear, not those that we will
242 * actually initialise below. Hence, don't put any more fields after
243 * the tail pointer in struct sk_buff!
245 memset(skb
, 0, offsetof(struct sk_buff
, tail
));
246 /* Account for allocated memory : skb + skb->head */
247 skb
->truesize
= SKB_TRUESIZE(size
);
248 skb
->pfmemalloc
= pfmemalloc
;
249 atomic_set(&skb
->users
, 1);
252 skb_reset_tail_pointer(skb
);
253 skb
->end
= skb
->tail
+ size
;
254 skb
->mac_header
= (typeof(skb
->mac_header
))~0U;
255 skb
->transport_header
= (typeof(skb
->transport_header
))~0U;
257 /* make sure we initialize shinfo sequentially */
258 shinfo
= skb_shinfo(skb
);
259 memset(shinfo
, 0, offsetof(struct skb_shared_info
, dataref
));
260 atomic_set(&shinfo
->dataref
, 1);
261 kmemcheck_annotate_variable(shinfo
->destructor_arg
);
263 if (flags
& SKB_ALLOC_FCLONE
) {
264 struct sk_buff_fclones
*fclones
;
266 fclones
= container_of(skb
, struct sk_buff_fclones
, skb1
);
268 kmemcheck_annotate_bitfield(&fclones
->skb2
, flags1
);
269 skb
->fclone
= SKB_FCLONE_ORIG
;
270 atomic_set(&fclones
->fclone_ref
, 1);
272 fclones
->skb2
.fclone
= SKB_FCLONE_CLONE
;
273 fclones
->skb2
.pfmemalloc
= pfmemalloc
;
278 kmem_cache_free(cache
, skb
);
282 EXPORT_SYMBOL(__alloc_skb
);
285 * __build_skb - build a network buffer
286 * @data: data buffer provided by caller
287 * @frag_size: size of data, or 0 if head was kmalloced
289 * Allocate a new &sk_buff. Caller provides space holding head and
290 * skb_shared_info. @data must have been allocated by kmalloc() only if
291 * @frag_size is 0, otherwise data should come from the page allocator
293 * The return is the new skb buffer.
294 * On a failure the return is %NULL, and @data is not freed.
296 * Before IO, driver allocates only data buffer where NIC put incoming frame
297 * Driver should add room at head (NET_SKB_PAD) and
298 * MUST add room at tail (SKB_DATA_ALIGN(skb_shared_info))
299 * After IO, driver calls build_skb(), to allocate sk_buff and populate it
300 * before giving packet to stack.
301 * RX rings only contains data buffers, not full skbs.
303 struct sk_buff
*__build_skb(void *data
, unsigned int frag_size
)
305 struct skb_shared_info
*shinfo
;
307 unsigned int size
= frag_size
? : ksize(data
);
309 skb
= kmem_cache_alloc(skbuff_head_cache
, GFP_ATOMIC
);
313 size
-= SKB_DATA_ALIGN(sizeof(struct skb_shared_info
));
315 memset(skb
, 0, offsetof(struct sk_buff
, tail
));
316 skb
->truesize
= SKB_TRUESIZE(size
);
317 atomic_set(&skb
->users
, 1);
320 skb_reset_tail_pointer(skb
);
321 skb
->end
= skb
->tail
+ size
;
322 skb
->mac_header
= (typeof(skb
->mac_header
))~0U;
323 skb
->transport_header
= (typeof(skb
->transport_header
))~0U;
325 /* make sure we initialize shinfo sequentially */
326 shinfo
= skb_shinfo(skb
);
327 memset(shinfo
, 0, offsetof(struct skb_shared_info
, dataref
));
328 atomic_set(&shinfo
->dataref
, 1);
329 kmemcheck_annotate_variable(shinfo
->destructor_arg
);
334 /* build_skb() is wrapper over __build_skb(), that specifically
335 * takes care of skb->head and skb->pfmemalloc
336 * This means that if @frag_size is not zero, then @data must be backed
337 * by a page fragment, not kmalloc() or vmalloc()
339 struct sk_buff
*build_skb(void *data
, unsigned int frag_size
)
341 struct sk_buff
*skb
= __build_skb(data
, frag_size
);
343 if (skb
&& frag_size
) {
345 if (page_is_pfmemalloc(virt_to_head_page(data
)))
350 EXPORT_SYMBOL(build_skb
);
352 static DEFINE_PER_CPU(struct page_frag_cache
, netdev_alloc_cache
);
353 static DEFINE_PER_CPU(struct page_frag_cache
, napi_alloc_cache
);
355 static void *__netdev_alloc_frag(unsigned int fragsz
, gfp_t gfp_mask
)
357 struct page_frag_cache
*nc
;
361 local_irq_save(flags
);
362 nc
= this_cpu_ptr(&netdev_alloc_cache
);
363 data
= __alloc_page_frag(nc
, fragsz
, gfp_mask
);
364 local_irq_restore(flags
);
369 * netdev_alloc_frag - allocate a page fragment
370 * @fragsz: fragment size
372 * Allocates a frag from a page for receive buffer.
373 * Uses GFP_ATOMIC allocations.
375 void *netdev_alloc_frag(unsigned int fragsz
)
377 return __netdev_alloc_frag(fragsz
, GFP_ATOMIC
| __GFP_COLD
);
379 EXPORT_SYMBOL(netdev_alloc_frag
);
381 static void *__napi_alloc_frag(unsigned int fragsz
, gfp_t gfp_mask
)
383 struct page_frag_cache
*nc
= this_cpu_ptr(&napi_alloc_cache
);
385 return __alloc_page_frag(nc
, fragsz
, gfp_mask
);
388 void *napi_alloc_frag(unsigned int fragsz
)
390 return __napi_alloc_frag(fragsz
, GFP_ATOMIC
| __GFP_COLD
);
392 EXPORT_SYMBOL(napi_alloc_frag
);
395 * __netdev_alloc_skb - allocate an skbuff for rx on a specific device
396 * @dev: network device to receive on
397 * @len: length to allocate
398 * @gfp_mask: get_free_pages mask, passed to alloc_skb
400 * Allocate a new &sk_buff and assign it a usage count of one. The
401 * buffer has NET_SKB_PAD headroom built in. Users should allocate
402 * the headroom they think they need without accounting for the
403 * built in space. The built in space is used for optimisations.
405 * %NULL is returned if there is no free memory.
407 struct sk_buff
*__netdev_alloc_skb(struct net_device
*dev
, unsigned int len
,
410 struct page_frag_cache
*nc
;
418 if ((len
> SKB_WITH_OVERHEAD(PAGE_SIZE
)) ||
419 (gfp_mask
& (__GFP_DIRECT_RECLAIM
| GFP_DMA
))) {
420 skb
= __alloc_skb(len
, gfp_mask
, SKB_ALLOC_RX
, NUMA_NO_NODE
);
426 len
+= SKB_DATA_ALIGN(sizeof(struct skb_shared_info
));
427 len
= SKB_DATA_ALIGN(len
);
429 if (sk_memalloc_socks())
430 gfp_mask
|= __GFP_MEMALLOC
;
432 local_irq_save(flags
);
434 nc
= this_cpu_ptr(&netdev_alloc_cache
);
435 data
= __alloc_page_frag(nc
, len
, gfp_mask
);
436 pfmemalloc
= nc
->pfmemalloc
;
438 local_irq_restore(flags
);
443 skb
= __build_skb(data
, len
);
444 if (unlikely(!skb
)) {
449 /* use OR instead of assignment to avoid clearing of bits in mask */
455 skb_reserve(skb
, NET_SKB_PAD
);
461 EXPORT_SYMBOL(__netdev_alloc_skb
);
464 * __napi_alloc_skb - allocate skbuff for rx in a specific NAPI instance
465 * @napi: napi instance this buffer was allocated for
466 * @len: length to allocate
467 * @gfp_mask: get_free_pages mask, passed to alloc_skb and alloc_pages
469 * Allocate a new sk_buff for use in NAPI receive. This buffer will
470 * attempt to allocate the head from a special reserved region used
471 * only for NAPI Rx allocation. By doing this we can save several
472 * CPU cycles by avoiding having to disable and re-enable IRQs.
474 * %NULL is returned if there is no free memory.
476 struct sk_buff
*__napi_alloc_skb(struct napi_struct
*napi
, unsigned int len
,
479 struct page_frag_cache
*nc
= this_cpu_ptr(&napi_alloc_cache
);
483 len
+= NET_SKB_PAD
+ NET_IP_ALIGN
;
485 if ((len
> SKB_WITH_OVERHEAD(PAGE_SIZE
)) ||
486 (gfp_mask
& (__GFP_DIRECT_RECLAIM
| GFP_DMA
))) {
487 skb
= __alloc_skb(len
, gfp_mask
, SKB_ALLOC_RX
, NUMA_NO_NODE
);
493 len
+= SKB_DATA_ALIGN(sizeof(struct skb_shared_info
));
494 len
= SKB_DATA_ALIGN(len
);
496 if (sk_memalloc_socks())
497 gfp_mask
|= __GFP_MEMALLOC
;
499 data
= __alloc_page_frag(nc
, len
, gfp_mask
);
503 skb
= __build_skb(data
, len
);
504 if (unlikely(!skb
)) {
509 /* use OR instead of assignment to avoid clearing of bits in mask */
515 skb_reserve(skb
, NET_SKB_PAD
+ NET_IP_ALIGN
);
516 skb
->dev
= napi
->dev
;
521 EXPORT_SYMBOL(__napi_alloc_skb
);
523 void skb_add_rx_frag(struct sk_buff
*skb
, int i
, struct page
*page
, int off
,
524 int size
, unsigned int truesize
)
526 skb_fill_page_desc(skb
, i
, page
, off
, size
);
528 skb
->data_len
+= size
;
529 skb
->truesize
+= truesize
;
531 EXPORT_SYMBOL(skb_add_rx_frag
);
533 void skb_coalesce_rx_frag(struct sk_buff
*skb
, int i
, int size
,
534 unsigned int truesize
)
536 skb_frag_t
*frag
= &skb_shinfo(skb
)->frags
[i
];
538 skb_frag_size_add(frag
, size
);
540 skb
->data_len
+= size
;
541 skb
->truesize
+= truesize
;
543 EXPORT_SYMBOL(skb_coalesce_rx_frag
);
545 static void skb_drop_list(struct sk_buff
**listp
)
547 kfree_skb_list(*listp
);
551 static inline void skb_drop_fraglist(struct sk_buff
*skb
)
553 skb_drop_list(&skb_shinfo(skb
)->frag_list
);
556 static void skb_clone_fraglist(struct sk_buff
*skb
)
558 struct sk_buff
*list
;
560 skb_walk_frags(skb
, list
)
564 static void skb_free_head(struct sk_buff
*skb
)
566 unsigned char *head
= skb
->head
;
574 static void skb_release_data(struct sk_buff
*skb
)
576 struct skb_shared_info
*shinfo
= skb_shinfo(skb
);
580 atomic_sub_return(skb
->nohdr
? (1 << SKB_DATAREF_SHIFT
) + 1 : 1,
584 for (i
= 0; i
< shinfo
->nr_frags
; i
++)
585 __skb_frag_unref(&shinfo
->frags
[i
]);
588 * If skb buf is from userspace, we need to notify the caller
589 * the lower device DMA has done;
591 if (shinfo
->tx_flags
& SKBTX_DEV_ZEROCOPY
) {
592 struct ubuf_info
*uarg
;
594 uarg
= shinfo
->destructor_arg
;
596 uarg
->callback(uarg
, true);
599 if (shinfo
->frag_list
)
600 kfree_skb_list(shinfo
->frag_list
);
606 * Free an skbuff by memory without cleaning the state.
608 static void kfree_skbmem(struct sk_buff
*skb
)
610 struct sk_buff_fclones
*fclones
;
612 switch (skb
->fclone
) {
613 case SKB_FCLONE_UNAVAILABLE
:
614 kmem_cache_free(skbuff_head_cache
, skb
);
617 case SKB_FCLONE_ORIG
:
618 fclones
= container_of(skb
, struct sk_buff_fclones
, skb1
);
620 /* We usually free the clone (TX completion) before original skb
621 * This test would have no chance to be true for the clone,
622 * while here, branch prediction will be good.
624 if (atomic_read(&fclones
->fclone_ref
) == 1)
628 default: /* SKB_FCLONE_CLONE */
629 fclones
= container_of(skb
, struct sk_buff_fclones
, skb2
);
632 if (!atomic_dec_and_test(&fclones
->fclone_ref
))
635 kmem_cache_free(skbuff_fclone_cache
, fclones
);
638 static void skb_release_head_state(struct sk_buff
*skb
)
642 secpath_put(skb
->sp
);
644 if (skb
->destructor
) {
646 skb
->destructor(skb
);
648 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
649 nf_conntrack_put(skb
->nfct
);
651 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
652 nf_bridge_put(skb
->nf_bridge
);
656 /* Free everything but the sk_buff shell. */
657 static void skb_release_all(struct sk_buff
*skb
)
659 skb_release_head_state(skb
);
660 if (likely(skb
->head
))
661 skb_release_data(skb
);
665 * __kfree_skb - private function
668 * Free an sk_buff. Release anything attached to the buffer.
669 * Clean the state. This is an internal helper function. Users should
670 * always call kfree_skb
673 void __kfree_skb(struct sk_buff
*skb
)
675 skb_release_all(skb
);
678 EXPORT_SYMBOL(__kfree_skb
);
681 * kfree_skb - free an sk_buff
682 * @skb: buffer to free
684 * Drop a reference to the buffer and free it if the usage count has
687 void kfree_skb(struct sk_buff
*skb
)
691 if (likely(atomic_read(&skb
->users
) == 1))
693 else if (likely(!atomic_dec_and_test(&skb
->users
)))
695 trace_kfree_skb(skb
, __builtin_return_address(0));
698 EXPORT_SYMBOL(kfree_skb
);
700 void kfree_skb_list(struct sk_buff
*segs
)
703 struct sk_buff
*next
= segs
->next
;
709 EXPORT_SYMBOL(kfree_skb_list
);
712 * skb_tx_error - report an sk_buff xmit error
713 * @skb: buffer that triggered an error
715 * Report xmit error if a device callback is tracking this skb.
716 * skb must be freed afterwards.
718 void skb_tx_error(struct sk_buff
*skb
)
720 if (skb_shinfo(skb
)->tx_flags
& SKBTX_DEV_ZEROCOPY
) {
721 struct ubuf_info
*uarg
;
723 uarg
= skb_shinfo(skb
)->destructor_arg
;
725 uarg
->callback(uarg
, false);
726 skb_shinfo(skb
)->tx_flags
&= ~SKBTX_DEV_ZEROCOPY
;
729 EXPORT_SYMBOL(skb_tx_error
);
732 * consume_skb - free an skbuff
733 * @skb: buffer to free
735 * Drop a ref to the buffer and free it if the usage count has hit zero
736 * Functions identically to kfree_skb, but kfree_skb assumes that the frame
737 * is being dropped after a failure and notes that
739 void consume_skb(struct sk_buff
*skb
)
743 if (likely(atomic_read(&skb
->users
) == 1))
745 else if (likely(!atomic_dec_and_test(&skb
->users
)))
747 trace_consume_skb(skb
);
750 EXPORT_SYMBOL(consume_skb
);
752 /* Make sure a field is enclosed inside headers_start/headers_end section */
753 #define CHECK_SKB_FIELD(field) \
754 BUILD_BUG_ON(offsetof(struct sk_buff, field) < \
755 offsetof(struct sk_buff, headers_start)); \
756 BUILD_BUG_ON(offsetof(struct sk_buff, field) > \
757 offsetof(struct sk_buff, headers_end)); \
759 static void __copy_skb_header(struct sk_buff *new, const struct sk_buff *old)
761 new->tstamp
= old
->tstamp
;
762 /* We do not copy old->sk */
764 memcpy(new->cb
, old
->cb
, sizeof(old
->cb
));
765 skb_dst_copy(new, old
);
767 new->sp
= secpath_get(old
->sp
);
769 __nf_copy(new, old
, false);
771 /* Note : this field could be in headers_start/headers_end section
772 * It is not yet because we do not want to have a 16 bit hole
774 new->queue_mapping
= old
->queue_mapping
;
776 memcpy(&new->headers_start
, &old
->headers_start
,
777 offsetof(struct sk_buff
, headers_end
) -
778 offsetof(struct sk_buff
, headers_start
));
779 CHECK_SKB_FIELD(protocol
);
780 CHECK_SKB_FIELD(csum
);
781 CHECK_SKB_FIELD(hash
);
782 CHECK_SKB_FIELD(priority
);
783 CHECK_SKB_FIELD(skb_iif
);
784 CHECK_SKB_FIELD(vlan_proto
);
785 CHECK_SKB_FIELD(vlan_tci
);
786 CHECK_SKB_FIELD(transport_header
);
787 CHECK_SKB_FIELD(network_header
);
788 CHECK_SKB_FIELD(mac_header
);
789 CHECK_SKB_FIELD(inner_protocol
);
790 CHECK_SKB_FIELD(inner_transport_header
);
791 CHECK_SKB_FIELD(inner_network_header
);
792 CHECK_SKB_FIELD(inner_mac_header
);
793 CHECK_SKB_FIELD(mark
);
794 #ifdef CONFIG_NETWORK_SECMARK
795 CHECK_SKB_FIELD(secmark
);
797 #ifdef CONFIG_NET_RX_BUSY_POLL
798 CHECK_SKB_FIELD(napi_id
);
801 CHECK_SKB_FIELD(sender_cpu
);
803 #ifdef CONFIG_NET_SCHED
804 CHECK_SKB_FIELD(tc_index
);
805 #ifdef CONFIG_NET_CLS_ACT
806 CHECK_SKB_FIELD(tc_verd
);
813 * You should not add any new code to this function. Add it to
814 * __copy_skb_header above instead.
816 static struct sk_buff
*__skb_clone(struct sk_buff
*n
, struct sk_buff
*skb
)
818 #define C(x) n->x = skb->x
820 n
->next
= n
->prev
= NULL
;
822 __copy_skb_header(n
, skb
);
827 n
->hdr_len
= skb
->nohdr
? skb_headroom(skb
) : skb
->hdr_len
;
830 n
->destructor
= NULL
;
837 atomic_set(&n
->users
, 1);
839 atomic_inc(&(skb_shinfo(skb
)->dataref
));
847 * skb_morph - morph one skb into another
848 * @dst: the skb to receive the contents
849 * @src: the skb to supply the contents
851 * This is identical to skb_clone except that the target skb is
852 * supplied by the user.
854 * The target skb is returned upon exit.
856 struct sk_buff
*skb_morph(struct sk_buff
*dst
, struct sk_buff
*src
)
858 skb_release_all(dst
);
859 return __skb_clone(dst
, src
);
861 EXPORT_SYMBOL_GPL(skb_morph
);
864 * skb_copy_ubufs - copy userspace skb frags buffers to kernel
865 * @skb: the skb to modify
866 * @gfp_mask: allocation priority
868 * This must be called on SKBTX_DEV_ZEROCOPY skb.
869 * It will copy all frags into kernel and drop the reference
870 * to userspace pages.
872 * If this function is called from an interrupt gfp_mask() must be
875 * Returns 0 on success or a negative error code on failure
876 * to allocate kernel memory to copy to.
878 int skb_copy_ubufs(struct sk_buff
*skb
, gfp_t gfp_mask
)
881 int num_frags
= skb_shinfo(skb
)->nr_frags
;
882 struct page
*page
, *head
= NULL
;
883 struct ubuf_info
*uarg
= skb_shinfo(skb
)->destructor_arg
;
885 for (i
= 0; i
< num_frags
; i
++) {
887 skb_frag_t
*f
= &skb_shinfo(skb
)->frags
[i
];
889 page
= alloc_page(gfp_mask
);
892 struct page
*next
= (struct page
*)page_private(head
);
898 vaddr
= kmap_atomic(skb_frag_page(f
));
899 memcpy(page_address(page
),
900 vaddr
+ f
->page_offset
, skb_frag_size(f
));
901 kunmap_atomic(vaddr
);
902 set_page_private(page
, (unsigned long)head
);
906 /* skb frags release userspace buffers */
907 for (i
= 0; i
< num_frags
; i
++)
908 skb_frag_unref(skb
, i
);
910 uarg
->callback(uarg
, false);
912 /* skb frags point to kernel buffers */
913 for (i
= num_frags
- 1; i
>= 0; i
--) {
914 __skb_fill_page_desc(skb
, i
, head
, 0,
915 skb_shinfo(skb
)->frags
[i
].size
);
916 head
= (struct page
*)page_private(head
);
919 skb_shinfo(skb
)->tx_flags
&= ~SKBTX_DEV_ZEROCOPY
;
922 EXPORT_SYMBOL_GPL(skb_copy_ubufs
);
925 * skb_clone - duplicate an sk_buff
926 * @skb: buffer to clone
927 * @gfp_mask: allocation priority
929 * Duplicate an &sk_buff. The new one is not owned by a socket. Both
930 * copies share the same packet data but not structure. The new
931 * buffer has a reference count of 1. If the allocation fails the
932 * function returns %NULL otherwise the new buffer is returned.
934 * If this function is called from an interrupt gfp_mask() must be
938 struct sk_buff
*skb_clone(struct sk_buff
*skb
, gfp_t gfp_mask
)
940 struct sk_buff_fclones
*fclones
= container_of(skb
,
941 struct sk_buff_fclones
,
945 if (skb_orphan_frags(skb
, gfp_mask
))
948 if (skb
->fclone
== SKB_FCLONE_ORIG
&&
949 atomic_read(&fclones
->fclone_ref
) == 1) {
951 atomic_set(&fclones
->fclone_ref
, 2);
953 if (skb_pfmemalloc(skb
))
954 gfp_mask
|= __GFP_MEMALLOC
;
956 n
= kmem_cache_alloc(skbuff_head_cache
, gfp_mask
);
960 kmemcheck_annotate_bitfield(n
, flags1
);
961 n
->fclone
= SKB_FCLONE_UNAVAILABLE
;
964 return __skb_clone(n
, skb
);
966 EXPORT_SYMBOL(skb_clone
);
968 static void skb_headers_offset_update(struct sk_buff
*skb
, int off
)
970 /* Only adjust this if it actually is csum_start rather than csum */
971 if (skb
->ip_summed
== CHECKSUM_PARTIAL
)
972 skb
->csum_start
+= off
;
973 /* {transport,network,mac}_header and tail are relative to skb->head */
974 skb
->transport_header
+= off
;
975 skb
->network_header
+= off
;
976 if (skb_mac_header_was_set(skb
))
977 skb
->mac_header
+= off
;
978 skb
->inner_transport_header
+= off
;
979 skb
->inner_network_header
+= off
;
980 skb
->inner_mac_header
+= off
;
983 static void copy_skb_header(struct sk_buff
*new, const struct sk_buff
*old
)
985 __copy_skb_header(new, old
);
987 skb_shinfo(new)->gso_size
= skb_shinfo(old
)->gso_size
;
988 skb_shinfo(new)->gso_segs
= skb_shinfo(old
)->gso_segs
;
989 skb_shinfo(new)->gso_type
= skb_shinfo(old
)->gso_type
;
992 static inline int skb_alloc_rx_flag(const struct sk_buff
*skb
)
994 if (skb_pfmemalloc(skb
))
1000 * skb_copy - create private copy of an sk_buff
1001 * @skb: buffer to copy
1002 * @gfp_mask: allocation priority
1004 * Make a copy of both an &sk_buff and its data. This is used when the
1005 * caller wishes to modify the data and needs a private copy of the
1006 * data to alter. Returns %NULL on failure or the pointer to the buffer
1007 * on success. The returned buffer has a reference count of 1.
1009 * As by-product this function converts non-linear &sk_buff to linear
1010 * one, so that &sk_buff becomes completely private and caller is allowed
1011 * to modify all the data of returned buffer. This means that this
1012 * function is not recommended for use in circumstances when only
1013 * header is going to be modified. Use pskb_copy() instead.
1016 struct sk_buff
*skb_copy(const struct sk_buff
*skb
, gfp_t gfp_mask
)
1018 int headerlen
= skb_headroom(skb
);
1019 unsigned int size
= skb_end_offset(skb
) + skb
->data_len
;
1020 struct sk_buff
*n
= __alloc_skb(size
, gfp_mask
,
1021 skb_alloc_rx_flag(skb
), NUMA_NO_NODE
);
1026 /* Set the data pointer */
1027 skb_reserve(n
, headerlen
);
1028 /* Set the tail pointer and length */
1029 skb_put(n
, skb
->len
);
1031 if (skb_copy_bits(skb
, -headerlen
, n
->head
, headerlen
+ skb
->len
))
1034 copy_skb_header(n
, skb
);
1037 EXPORT_SYMBOL(skb_copy
);
1040 * __pskb_copy_fclone - create copy of an sk_buff with private head.
1041 * @skb: buffer to copy
1042 * @headroom: headroom of new skb
1043 * @gfp_mask: allocation priority
1044 * @fclone: if true allocate the copy of the skb from the fclone
1045 * cache instead of the head cache; it is recommended to set this
1046 * to true for the cases where the copy will likely be cloned
1048 * Make a copy of both an &sk_buff and part of its data, located
1049 * in header. Fragmented data remain shared. This is used when
1050 * the caller wishes to modify only header of &sk_buff and needs
1051 * private copy of the header to alter. Returns %NULL on failure
1052 * or the pointer to the buffer on success.
1053 * The returned buffer has a reference count of 1.
1056 struct sk_buff
*__pskb_copy_fclone(struct sk_buff
*skb
, int headroom
,
1057 gfp_t gfp_mask
, bool fclone
)
1059 unsigned int size
= skb_headlen(skb
) + headroom
;
1060 int flags
= skb_alloc_rx_flag(skb
) | (fclone
? SKB_ALLOC_FCLONE
: 0);
1061 struct sk_buff
*n
= __alloc_skb(size
, gfp_mask
, flags
, NUMA_NO_NODE
);
1066 /* Set the data pointer */
1067 skb_reserve(n
, headroom
);
1068 /* Set the tail pointer and length */
1069 skb_put(n
, skb_headlen(skb
));
1070 /* Copy the bytes */
1071 skb_copy_from_linear_data(skb
, n
->data
, n
->len
);
1073 n
->truesize
+= skb
->data_len
;
1074 n
->data_len
= skb
->data_len
;
1077 if (skb_shinfo(skb
)->nr_frags
) {
1080 if (skb_orphan_frags(skb
, gfp_mask
)) {
1085 for (i
= 0; i
< skb_shinfo(skb
)->nr_frags
; i
++) {
1086 skb_shinfo(n
)->frags
[i
] = skb_shinfo(skb
)->frags
[i
];
1087 skb_frag_ref(skb
, i
);
1089 skb_shinfo(n
)->nr_frags
= i
;
1092 if (skb_has_frag_list(skb
)) {
1093 skb_shinfo(n
)->frag_list
= skb_shinfo(skb
)->frag_list
;
1094 skb_clone_fraglist(n
);
1097 copy_skb_header(n
, skb
);
1101 EXPORT_SYMBOL(__pskb_copy_fclone
);
1104 * pskb_expand_head - reallocate header of &sk_buff
1105 * @skb: buffer to reallocate
1106 * @nhead: room to add at head
1107 * @ntail: room to add at tail
1108 * @gfp_mask: allocation priority
1110 * Expands (or creates identical copy, if @nhead and @ntail are zero)
1111 * header of @skb. &sk_buff itself is not changed. &sk_buff MUST have
1112 * reference count of 1. Returns zero in the case of success or error,
1113 * if expansion failed. In the last case, &sk_buff is not changed.
1115 * All the pointers pointing into skb header may change and must be
1116 * reloaded after call to this function.
1119 int pskb_expand_head(struct sk_buff
*skb
, int nhead
, int ntail
,
1124 int size
= nhead
+ skb_end_offset(skb
) + ntail
;
1129 if (skb_shared(skb
))
1132 size
= SKB_DATA_ALIGN(size
);
1134 if (skb_pfmemalloc(skb
))
1135 gfp_mask
|= __GFP_MEMALLOC
;
1136 data
= kmalloc_reserve(size
+ SKB_DATA_ALIGN(sizeof(struct skb_shared_info
)),
1137 gfp_mask
, NUMA_NO_NODE
, NULL
);
1140 size
= SKB_WITH_OVERHEAD(ksize(data
));
1142 /* Copy only real data... and, alas, header. This should be
1143 * optimized for the cases when header is void.
1145 memcpy(data
+ nhead
, skb
->head
, skb_tail_pointer(skb
) - skb
->head
);
1147 memcpy((struct skb_shared_info
*)(data
+ size
),
1149 offsetof(struct skb_shared_info
, frags
[skb_shinfo(skb
)->nr_frags
]));
1152 * if shinfo is shared we must drop the old head gracefully, but if it
1153 * is not we can just drop the old head and let the existing refcount
1154 * be since all we did is relocate the values
1156 if (skb_cloned(skb
)) {
1157 /* copy this zero copy skb frags */
1158 if (skb_orphan_frags(skb
, gfp_mask
))
1160 for (i
= 0; i
< skb_shinfo(skb
)->nr_frags
; i
++)
1161 skb_frag_ref(skb
, i
);
1163 if (skb_has_frag_list(skb
))
1164 skb_clone_fraglist(skb
);
1166 skb_release_data(skb
);
1170 off
= (data
+ nhead
) - skb
->head
;
1175 #ifdef NET_SKBUFF_DATA_USES_OFFSET
1179 skb
->end
= skb
->head
+ size
;
1182 skb_headers_offset_update(skb
, nhead
);
1186 atomic_set(&skb_shinfo(skb
)->dataref
, 1);
1194 EXPORT_SYMBOL(pskb_expand_head
);
1196 /* Make private copy of skb with writable head and some headroom */
1198 struct sk_buff
*skb_realloc_headroom(struct sk_buff
*skb
, unsigned int headroom
)
1200 struct sk_buff
*skb2
;
1201 int delta
= headroom
- skb_headroom(skb
);
1204 skb2
= pskb_copy(skb
, GFP_ATOMIC
);
1206 skb2
= skb_clone(skb
, GFP_ATOMIC
);
1207 if (skb2
&& pskb_expand_head(skb2
, SKB_DATA_ALIGN(delta
), 0,
1215 EXPORT_SYMBOL(skb_realloc_headroom
);
1218 * skb_copy_expand - copy and expand sk_buff
1219 * @skb: buffer to copy
1220 * @newheadroom: new free bytes at head
1221 * @newtailroom: new free bytes at tail
1222 * @gfp_mask: allocation priority
1224 * Make a copy of both an &sk_buff and its data and while doing so
1225 * allocate additional space.
1227 * This is used when the caller wishes to modify the data and needs a
1228 * private copy of the data to alter as well as more space for new fields.
1229 * Returns %NULL on failure or the pointer to the buffer
1230 * on success. The returned buffer has a reference count of 1.
1232 * You must pass %GFP_ATOMIC as the allocation priority if this function
1233 * is called from an interrupt.
1235 struct sk_buff
*skb_copy_expand(const struct sk_buff
*skb
,
1236 int newheadroom
, int newtailroom
,
1240 * Allocate the copy buffer
1242 struct sk_buff
*n
= __alloc_skb(newheadroom
+ skb
->len
+ newtailroom
,
1243 gfp_mask
, skb_alloc_rx_flag(skb
),
1245 int oldheadroom
= skb_headroom(skb
);
1246 int head_copy_len
, head_copy_off
;
1251 skb_reserve(n
, newheadroom
);
1253 /* Set the tail pointer and length */
1254 skb_put(n
, skb
->len
);
1256 head_copy_len
= oldheadroom
;
1258 if (newheadroom
<= head_copy_len
)
1259 head_copy_len
= newheadroom
;
1261 head_copy_off
= newheadroom
- head_copy_len
;
1263 /* Copy the linear header and data. */
1264 if (skb_copy_bits(skb
, -head_copy_len
, n
->head
+ head_copy_off
,
1265 skb
->len
+ head_copy_len
))
1268 copy_skb_header(n
, skb
);
1270 skb_headers_offset_update(n
, newheadroom
- oldheadroom
);
1274 EXPORT_SYMBOL(skb_copy_expand
);
1277 * skb_pad - zero pad the tail of an skb
1278 * @skb: buffer to pad
1279 * @pad: space to pad
1281 * Ensure that a buffer is followed by a padding area that is zero
1282 * filled. Used by network drivers which may DMA or transfer data
1283 * beyond the buffer end onto the wire.
1285 * May return error in out of memory cases. The skb is freed on error.
1288 int skb_pad(struct sk_buff
*skb
, int pad
)
1293 /* If the skbuff is non linear tailroom is always zero.. */
1294 if (!skb_cloned(skb
) && skb_tailroom(skb
) >= pad
) {
1295 memset(skb
->data
+skb
->len
, 0, pad
);
1299 ntail
= skb
->data_len
+ pad
- (skb
->end
- skb
->tail
);
1300 if (likely(skb_cloned(skb
) || ntail
> 0)) {
1301 err
= pskb_expand_head(skb
, 0, ntail
, GFP_ATOMIC
);
1306 /* FIXME: The use of this function with non-linear skb's really needs
1309 err
= skb_linearize(skb
);
1313 memset(skb
->data
+ skb
->len
, 0, pad
);
1320 EXPORT_SYMBOL(skb_pad
);
1323 * pskb_put - add data to the tail of a potentially fragmented buffer
1324 * @skb: start of the buffer to use
1325 * @tail: tail fragment of the buffer to use
1326 * @len: amount of data to add
1328 * This function extends the used data area of the potentially
1329 * fragmented buffer. @tail must be the last fragment of @skb -- or
1330 * @skb itself. If this would exceed the total buffer size the kernel
1331 * will panic. A pointer to the first byte of the extra data is
1335 unsigned char *pskb_put(struct sk_buff
*skb
, struct sk_buff
*tail
, int len
)
1338 skb
->data_len
+= len
;
1341 return skb_put(tail
, len
);
1343 EXPORT_SYMBOL_GPL(pskb_put
);
1346 * skb_put - add data to a buffer
1347 * @skb: buffer to use
1348 * @len: amount of data to add
1350 * This function extends the used data area of the buffer. If this would
1351 * exceed the total buffer size the kernel will panic. A pointer to the
1352 * first byte of the extra data is returned.
1354 unsigned char *skb_put(struct sk_buff
*skb
, unsigned int len
)
1356 unsigned char *tmp
= skb_tail_pointer(skb
);
1357 SKB_LINEAR_ASSERT(skb
);
1360 if (unlikely(skb
->tail
> skb
->end
))
1361 skb_over_panic(skb
, len
, __builtin_return_address(0));
1364 EXPORT_SYMBOL(skb_put
);
1367 * skb_push - add data to the start of a buffer
1368 * @skb: buffer to use
1369 * @len: amount of data to add
1371 * This function extends the used data area of the buffer at the buffer
1372 * start. If this would exceed the total buffer headroom the kernel will
1373 * panic. A pointer to the first byte of the extra data is returned.
1375 unsigned char *skb_push(struct sk_buff
*skb
, unsigned int len
)
1379 if (unlikely(skb
->data
<skb
->head
))
1380 skb_under_panic(skb
, len
, __builtin_return_address(0));
1383 EXPORT_SYMBOL(skb_push
);
1386 * skb_pull - remove data from the start of a buffer
1387 * @skb: buffer to use
1388 * @len: amount of data to remove
1390 * This function removes data from the start of a buffer, returning
1391 * the memory to the headroom. A pointer to the next data in the buffer
1392 * is returned. Once the data has been pulled future pushes will overwrite
1395 unsigned char *skb_pull(struct sk_buff
*skb
, unsigned int len
)
1397 return skb_pull_inline(skb
, len
);
1399 EXPORT_SYMBOL(skb_pull
);
1402 * skb_trim - remove end from a buffer
1403 * @skb: buffer to alter
1406 * Cut the length of a buffer down by removing data from the tail. If
1407 * the buffer is already under the length specified it is not modified.
1408 * The skb must be linear.
1410 void skb_trim(struct sk_buff
*skb
, unsigned int len
)
1413 __skb_trim(skb
, len
);
1415 EXPORT_SYMBOL(skb_trim
);
1417 /* Trims skb to length len. It can change skb pointers.
1420 int ___pskb_trim(struct sk_buff
*skb
, unsigned int len
)
1422 struct sk_buff
**fragp
;
1423 struct sk_buff
*frag
;
1424 int offset
= skb_headlen(skb
);
1425 int nfrags
= skb_shinfo(skb
)->nr_frags
;
1429 if (skb_cloned(skb
) &&
1430 unlikely((err
= pskb_expand_head(skb
, 0, 0, GFP_ATOMIC
))))
1437 for (; i
< nfrags
; i
++) {
1438 int end
= offset
+ skb_frag_size(&skb_shinfo(skb
)->frags
[i
]);
1445 skb_frag_size_set(&skb_shinfo(skb
)->frags
[i
++], len
- offset
);
1448 skb_shinfo(skb
)->nr_frags
= i
;
1450 for (; i
< nfrags
; i
++)
1451 skb_frag_unref(skb
, i
);
1453 if (skb_has_frag_list(skb
))
1454 skb_drop_fraglist(skb
);
1458 for (fragp
= &skb_shinfo(skb
)->frag_list
; (frag
= *fragp
);
1459 fragp
= &frag
->next
) {
1460 int end
= offset
+ frag
->len
;
1462 if (skb_shared(frag
)) {
1463 struct sk_buff
*nfrag
;
1465 nfrag
= skb_clone(frag
, GFP_ATOMIC
);
1466 if (unlikely(!nfrag
))
1469 nfrag
->next
= frag
->next
;
1481 unlikely((err
= pskb_trim(frag
, len
- offset
))))
1485 skb_drop_list(&frag
->next
);
1490 if (len
> skb_headlen(skb
)) {
1491 skb
->data_len
-= skb
->len
- len
;
1496 skb_set_tail_pointer(skb
, len
);
1501 EXPORT_SYMBOL(___pskb_trim
);
1504 * __pskb_pull_tail - advance tail of skb header
1505 * @skb: buffer to reallocate
1506 * @delta: number of bytes to advance tail
1508 * The function makes a sense only on a fragmented &sk_buff,
1509 * it expands header moving its tail forward and copying necessary
1510 * data from fragmented part.
1512 * &sk_buff MUST have reference count of 1.
1514 * Returns %NULL (and &sk_buff does not change) if pull failed
1515 * or value of new tail of skb in the case of success.
1517 * All the pointers pointing into skb header may change and must be
1518 * reloaded after call to this function.
1521 /* Moves tail of skb head forward, copying data from fragmented part,
1522 * when it is necessary.
1523 * 1. It may fail due to malloc failure.
1524 * 2. It may change skb pointers.
1526 * It is pretty complicated. Luckily, it is called only in exceptional cases.
1528 unsigned char *__pskb_pull_tail(struct sk_buff
*skb
, int delta
)
1530 /* If skb has not enough free space at tail, get new one
1531 * plus 128 bytes for future expansions. If we have enough
1532 * room at tail, reallocate without expansion only if skb is cloned.
1534 int i
, k
, eat
= (skb
->tail
+ delta
) - skb
->end
;
1536 if (eat
> 0 || skb_cloned(skb
)) {
1537 if (pskb_expand_head(skb
, 0, eat
> 0 ? eat
+ 128 : 0,
1542 if (skb_copy_bits(skb
, skb_headlen(skb
), skb_tail_pointer(skb
), delta
))
1545 /* Optimization: no fragments, no reasons to preestimate
1546 * size of pulled pages. Superb.
1548 if (!skb_has_frag_list(skb
))
1551 /* Estimate size of pulled pages. */
1553 for (i
= 0; i
< skb_shinfo(skb
)->nr_frags
; i
++) {
1554 int size
= skb_frag_size(&skb_shinfo(skb
)->frags
[i
]);
1561 /* If we need update frag list, we are in troubles.
1562 * Certainly, it possible to add an offset to skb data,
1563 * but taking into account that pulling is expected to
1564 * be very rare operation, it is worth to fight against
1565 * further bloating skb head and crucify ourselves here instead.
1566 * Pure masohism, indeed. 8)8)
1569 struct sk_buff
*list
= skb_shinfo(skb
)->frag_list
;
1570 struct sk_buff
*clone
= NULL
;
1571 struct sk_buff
*insp
= NULL
;
1576 if (list
->len
<= eat
) {
1577 /* Eaten as whole. */
1582 /* Eaten partially. */
1584 if (skb_shared(list
)) {
1585 /* Sucks! We need to fork list. :-( */
1586 clone
= skb_clone(list
, GFP_ATOMIC
);
1592 /* This may be pulled without
1596 if (!pskb_pull(list
, eat
)) {
1604 /* Free pulled out fragments. */
1605 while ((list
= skb_shinfo(skb
)->frag_list
) != insp
) {
1606 skb_shinfo(skb
)->frag_list
= list
->next
;
1609 /* And insert new clone at head. */
1612 skb_shinfo(skb
)->frag_list
= clone
;
1615 /* Success! Now we may commit changes to skb data. */
1620 for (i
= 0; i
< skb_shinfo(skb
)->nr_frags
; i
++) {
1621 int size
= skb_frag_size(&skb_shinfo(skb
)->frags
[i
]);
1624 skb_frag_unref(skb
, i
);
1627 skb_shinfo(skb
)->frags
[k
] = skb_shinfo(skb
)->frags
[i
];
1629 skb_shinfo(skb
)->frags
[k
].page_offset
+= eat
;
1630 skb_frag_size_sub(&skb_shinfo(skb
)->frags
[k
], eat
);
1636 skb_shinfo(skb
)->nr_frags
= k
;
1639 skb
->data_len
-= delta
;
1641 return skb_tail_pointer(skb
);
1643 EXPORT_SYMBOL(__pskb_pull_tail
);
1646 * skb_copy_bits - copy bits from skb to kernel buffer
1648 * @offset: offset in source
1649 * @to: destination buffer
1650 * @len: number of bytes to copy
1652 * Copy the specified number of bytes from the source skb to the
1653 * destination buffer.
1656 * If its prototype is ever changed,
1657 * check arch/{*}/net/{*}.S files,
1658 * since it is called from BPF assembly code.
1660 int skb_copy_bits(const struct sk_buff
*skb
, int offset
, void *to
, int len
)
1662 int start
= skb_headlen(skb
);
1663 struct sk_buff
*frag_iter
;
1666 if (offset
> (int)skb
->len
- len
)
1670 if ((copy
= start
- offset
) > 0) {
1673 skb_copy_from_linear_data_offset(skb
, offset
, to
, copy
);
1674 if ((len
-= copy
) == 0)
1680 for (i
= 0; i
< skb_shinfo(skb
)->nr_frags
; i
++) {
1682 skb_frag_t
*f
= &skb_shinfo(skb
)->frags
[i
];
1684 WARN_ON(start
> offset
+ len
);
1686 end
= start
+ skb_frag_size(f
);
1687 if ((copy
= end
- offset
) > 0) {
1693 vaddr
= kmap_atomic(skb_frag_page(f
));
1695 vaddr
+ f
->page_offset
+ offset
- start
,
1697 kunmap_atomic(vaddr
);
1699 if ((len
-= copy
) == 0)
1707 skb_walk_frags(skb
, frag_iter
) {
1710 WARN_ON(start
> offset
+ len
);
1712 end
= start
+ frag_iter
->len
;
1713 if ((copy
= end
- offset
) > 0) {
1716 if (skb_copy_bits(frag_iter
, offset
- start
, to
, copy
))
1718 if ((len
-= copy
) == 0)
1732 EXPORT_SYMBOL(skb_copy_bits
);
1735 * Callback from splice_to_pipe(), if we need to release some pages
1736 * at the end of the spd in case we error'ed out in filling the pipe.
1738 static void sock_spd_release(struct splice_pipe_desc
*spd
, unsigned int i
)
1740 put_page(spd
->pages
[i
]);
1743 static struct page
*linear_to_page(struct page
*page
, unsigned int *len
,
1744 unsigned int *offset
,
1747 struct page_frag
*pfrag
= sk_page_frag(sk
);
1749 if (!sk_page_frag_refill(sk
, pfrag
))
1752 *len
= min_t(unsigned int, *len
, pfrag
->size
- pfrag
->offset
);
1754 memcpy(page_address(pfrag
->page
) + pfrag
->offset
,
1755 page_address(page
) + *offset
, *len
);
1756 *offset
= pfrag
->offset
;
1757 pfrag
->offset
+= *len
;
1762 static bool spd_can_coalesce(const struct splice_pipe_desc
*spd
,
1764 unsigned int offset
)
1766 return spd
->nr_pages
&&
1767 spd
->pages
[spd
->nr_pages
- 1] == page
&&
1768 (spd
->partial
[spd
->nr_pages
- 1].offset
+
1769 spd
->partial
[spd
->nr_pages
- 1].len
== offset
);
1773 * Fill page/offset/length into spd, if it can hold more pages.
1775 static bool spd_fill_page(struct splice_pipe_desc
*spd
,
1776 struct pipe_inode_info
*pipe
, struct page
*page
,
1777 unsigned int *len
, unsigned int offset
,
1781 if (unlikely(spd
->nr_pages
== MAX_SKB_FRAGS
))
1785 page
= linear_to_page(page
, len
, &offset
, sk
);
1789 if (spd_can_coalesce(spd
, page
, offset
)) {
1790 spd
->partial
[spd
->nr_pages
- 1].len
+= *len
;
1794 spd
->pages
[spd
->nr_pages
] = page
;
1795 spd
->partial
[spd
->nr_pages
].len
= *len
;
1796 spd
->partial
[spd
->nr_pages
].offset
= offset
;
1802 static bool __splice_segment(struct page
*page
, unsigned int poff
,
1803 unsigned int plen
, unsigned int *off
,
1805 struct splice_pipe_desc
*spd
, bool linear
,
1807 struct pipe_inode_info
*pipe
)
1812 /* skip this segment if already processed */
1818 /* ignore any bits we already processed */
1824 unsigned int flen
= min(*len
, plen
);
1826 if (spd_fill_page(spd
, pipe
, page
, &flen
, poff
,
1832 } while (*len
&& plen
);
1838 * Map linear and fragment data from the skb to spd. It reports true if the
1839 * pipe is full or if we already spliced the requested length.
1841 static bool __skb_splice_bits(struct sk_buff
*skb
, struct pipe_inode_info
*pipe
,
1842 unsigned int *offset
, unsigned int *len
,
1843 struct splice_pipe_desc
*spd
, struct sock
*sk
)
1847 /* map the linear part :
1848 * If skb->head_frag is set, this 'linear' part is backed by a
1849 * fragment, and if the head is not shared with any clones then
1850 * we can avoid a copy since we own the head portion of this page.
1852 if (__splice_segment(virt_to_page(skb
->data
),
1853 (unsigned long) skb
->data
& (PAGE_SIZE
- 1),
1856 skb_head_is_locked(skb
),
1861 * then map the fragments
1863 for (seg
= 0; seg
< skb_shinfo(skb
)->nr_frags
; seg
++) {
1864 const skb_frag_t
*f
= &skb_shinfo(skb
)->frags
[seg
];
1866 if (__splice_segment(skb_frag_page(f
),
1867 f
->page_offset
, skb_frag_size(f
),
1868 offset
, len
, spd
, false, sk
, pipe
))
1875 ssize_t
skb_socket_splice(struct sock
*sk
,
1876 struct pipe_inode_info
*pipe
,
1877 struct splice_pipe_desc
*spd
)
1881 /* Drop the socket lock, otherwise we have reverse
1882 * locking dependencies between sk_lock and i_mutex
1883 * here as compared to sendfile(). We enter here
1884 * with the socket lock held, and splice_to_pipe() will
1885 * grab the pipe inode lock. For sendfile() emulation,
1886 * we call into ->sendpage() with the i_mutex lock held
1887 * and networking will grab the socket lock.
1890 ret
= splice_to_pipe(pipe
, spd
);
1897 * Map data from the skb to a pipe. Should handle both the linear part,
1898 * the fragments, and the frag list. It does NOT handle frag lists within
1899 * the frag list, if such a thing exists. We'd probably need to recurse to
1900 * handle that cleanly.
1902 int skb_splice_bits(struct sk_buff
*skb
, struct sock
*sk
, unsigned int offset
,
1903 struct pipe_inode_info
*pipe
, unsigned int tlen
,
1905 ssize_t (*splice_cb
)(struct sock
*,
1906 struct pipe_inode_info
*,
1907 struct splice_pipe_desc
*))
1909 struct partial_page partial
[MAX_SKB_FRAGS
];
1910 struct page
*pages
[MAX_SKB_FRAGS
];
1911 struct splice_pipe_desc spd
= {
1914 .nr_pages_max
= MAX_SKB_FRAGS
,
1916 .ops
= &nosteal_pipe_buf_ops
,
1917 .spd_release
= sock_spd_release
,
1919 struct sk_buff
*frag_iter
;
1923 * __skb_splice_bits() only fails if the output has no room left,
1924 * so no point in going over the frag_list for the error case.
1926 if (__skb_splice_bits(skb
, pipe
, &offset
, &tlen
, &spd
, sk
))
1932 * now see if we have a frag_list to map
1934 skb_walk_frags(skb
, frag_iter
) {
1937 if (__skb_splice_bits(frag_iter
, pipe
, &offset
, &tlen
, &spd
, sk
))
1943 ret
= splice_cb(sk
, pipe
, &spd
);
1947 EXPORT_SYMBOL_GPL(skb_splice_bits
);
1950 * skb_store_bits - store bits from kernel buffer to skb
1951 * @skb: destination buffer
1952 * @offset: offset in destination
1953 * @from: source buffer
1954 * @len: number of bytes to copy
1956 * Copy the specified number of bytes from the source buffer to the
1957 * destination skb. This function handles all the messy bits of
1958 * traversing fragment lists and such.
1961 int skb_store_bits(struct sk_buff
*skb
, int offset
, const void *from
, int len
)
1963 int start
= skb_headlen(skb
);
1964 struct sk_buff
*frag_iter
;
1967 if (offset
> (int)skb
->len
- len
)
1970 if ((copy
= start
- offset
) > 0) {
1973 skb_copy_to_linear_data_offset(skb
, offset
, from
, copy
);
1974 if ((len
-= copy
) == 0)
1980 for (i
= 0; i
< skb_shinfo(skb
)->nr_frags
; i
++) {
1981 skb_frag_t
*frag
= &skb_shinfo(skb
)->frags
[i
];
1984 WARN_ON(start
> offset
+ len
);
1986 end
= start
+ skb_frag_size(frag
);
1987 if ((copy
= end
- offset
) > 0) {
1993 vaddr
= kmap_atomic(skb_frag_page(frag
));
1994 memcpy(vaddr
+ frag
->page_offset
+ offset
- start
,
1996 kunmap_atomic(vaddr
);
1998 if ((len
-= copy
) == 0)
2006 skb_walk_frags(skb
, frag_iter
) {
2009 WARN_ON(start
> offset
+ len
);
2011 end
= start
+ frag_iter
->len
;
2012 if ((copy
= end
- offset
) > 0) {
2015 if (skb_store_bits(frag_iter
, offset
- start
,
2018 if ((len
-= copy
) == 0)
2031 EXPORT_SYMBOL(skb_store_bits
);
2033 /* Checksum skb data. */
2034 __wsum
__skb_checksum(const struct sk_buff
*skb
, int offset
, int len
,
2035 __wsum csum
, const struct skb_checksum_ops
*ops
)
2037 int start
= skb_headlen(skb
);
2038 int i
, copy
= start
- offset
;
2039 struct sk_buff
*frag_iter
;
2042 /* Checksum header. */
2046 csum
= ops
->update(skb
->data
+ offset
, copy
, csum
);
2047 if ((len
-= copy
) == 0)
2053 for (i
= 0; i
< skb_shinfo(skb
)->nr_frags
; i
++) {
2055 skb_frag_t
*frag
= &skb_shinfo(skb
)->frags
[i
];
2057 WARN_ON(start
> offset
+ len
);
2059 end
= start
+ skb_frag_size(frag
);
2060 if ((copy
= end
- offset
) > 0) {
2066 vaddr
= kmap_atomic(skb_frag_page(frag
));
2067 csum2
= ops
->update(vaddr
+ frag
->page_offset
+
2068 offset
- start
, copy
, 0);
2069 kunmap_atomic(vaddr
);
2070 csum
= ops
->combine(csum
, csum2
, pos
, copy
);
2079 skb_walk_frags(skb
, frag_iter
) {
2082 WARN_ON(start
> offset
+ len
);
2084 end
= start
+ frag_iter
->len
;
2085 if ((copy
= end
- offset
) > 0) {
2089 csum2
= __skb_checksum(frag_iter
, offset
- start
,
2091 csum
= ops
->combine(csum
, csum2
, pos
, copy
);
2092 if ((len
-= copy
) == 0)
2103 EXPORT_SYMBOL(__skb_checksum
);
2105 __wsum
skb_checksum(const struct sk_buff
*skb
, int offset
,
2106 int len
, __wsum csum
)
2108 const struct skb_checksum_ops ops
= {
2109 .update
= csum_partial_ext
,
2110 .combine
= csum_block_add_ext
,
2113 return __skb_checksum(skb
, offset
, len
, csum
, &ops
);
2115 EXPORT_SYMBOL(skb_checksum
);
2117 /* Both of above in one bottle. */
2119 __wsum
skb_copy_and_csum_bits(const struct sk_buff
*skb
, int offset
,
2120 u8
*to
, int len
, __wsum csum
)
2122 int start
= skb_headlen(skb
);
2123 int i
, copy
= start
- offset
;
2124 struct sk_buff
*frag_iter
;
2131 csum
= csum_partial_copy_nocheck(skb
->data
+ offset
, to
,
2133 if ((len
-= copy
) == 0)
2140 for (i
= 0; i
< skb_shinfo(skb
)->nr_frags
; i
++) {
2143 WARN_ON(start
> offset
+ len
);
2145 end
= start
+ skb_frag_size(&skb_shinfo(skb
)->frags
[i
]);
2146 if ((copy
= end
- offset
) > 0) {
2149 skb_frag_t
*frag
= &skb_shinfo(skb
)->frags
[i
];
2153 vaddr
= kmap_atomic(skb_frag_page(frag
));
2154 csum2
= csum_partial_copy_nocheck(vaddr
+
2158 kunmap_atomic(vaddr
);
2159 csum
= csum_block_add(csum
, csum2
, pos
);
2169 skb_walk_frags(skb
, frag_iter
) {
2173 WARN_ON(start
> offset
+ len
);
2175 end
= start
+ frag_iter
->len
;
2176 if ((copy
= end
- offset
) > 0) {
2179 csum2
= skb_copy_and_csum_bits(frag_iter
,
2182 csum
= csum_block_add(csum
, csum2
, pos
);
2183 if ((len
-= copy
) == 0)
2194 EXPORT_SYMBOL(skb_copy_and_csum_bits
);
2197 * skb_zerocopy_headlen - Calculate headroom needed for skb_zerocopy()
2198 * @from: source buffer
2200 * Calculates the amount of linear headroom needed in the 'to' skb passed
2201 * into skb_zerocopy().
2204 skb_zerocopy_headlen(const struct sk_buff
*from
)
2206 unsigned int hlen
= 0;
2208 if (!from
->head_frag
||
2209 skb_headlen(from
) < L1_CACHE_BYTES
||
2210 skb_shinfo(from
)->nr_frags
>= MAX_SKB_FRAGS
)
2211 hlen
= skb_headlen(from
);
2213 if (skb_has_frag_list(from
))
2218 EXPORT_SYMBOL_GPL(skb_zerocopy_headlen
);
2221 * skb_zerocopy - Zero copy skb to skb
2222 * @to: destination buffer
2223 * @from: source buffer
2224 * @len: number of bytes to copy from source buffer
2225 * @hlen: size of linear headroom in destination buffer
2227 * Copies up to `len` bytes from `from` to `to` by creating references
2228 * to the frags in the source buffer.
2230 * The `hlen` as calculated by skb_zerocopy_headlen() specifies the
2231 * headroom in the `to` buffer.
2234 * 0: everything is OK
2235 * -ENOMEM: couldn't orphan frags of @from due to lack of memory
2236 * -EFAULT: skb_copy_bits() found some problem with skb geometry
2239 skb_zerocopy(struct sk_buff
*to
, struct sk_buff
*from
, int len
, int hlen
)
2242 int plen
= 0; /* length of skb->head fragment */
2245 unsigned int offset
;
2247 BUG_ON(!from
->head_frag
&& !hlen
);
2249 /* dont bother with small payloads */
2250 if (len
<= skb_tailroom(to
))
2251 return skb_copy_bits(from
, 0, skb_put(to
, len
), len
);
2254 ret
= skb_copy_bits(from
, 0, skb_put(to
, hlen
), hlen
);
2259 plen
= min_t(int, skb_headlen(from
), len
);
2261 page
= virt_to_head_page(from
->head
);
2262 offset
= from
->data
- (unsigned char *)page_address(page
);
2263 __skb_fill_page_desc(to
, 0, page
, offset
, plen
);
2270 to
->truesize
+= len
+ plen
;
2271 to
->len
+= len
+ plen
;
2272 to
->data_len
+= len
+ plen
;
2274 if (unlikely(skb_orphan_frags(from
, GFP_ATOMIC
))) {
2279 for (i
= 0; i
< skb_shinfo(from
)->nr_frags
; i
++) {
2282 skb_shinfo(to
)->frags
[j
] = skb_shinfo(from
)->frags
[i
];
2283 skb_shinfo(to
)->frags
[j
].size
= min_t(int, skb_shinfo(to
)->frags
[j
].size
, len
);
2284 len
-= skb_shinfo(to
)->frags
[j
].size
;
2285 skb_frag_ref(to
, j
);
2288 skb_shinfo(to
)->nr_frags
= j
;
2292 EXPORT_SYMBOL_GPL(skb_zerocopy
);
2294 void skb_copy_and_csum_dev(const struct sk_buff
*skb
, u8
*to
)
2299 if (skb
->ip_summed
== CHECKSUM_PARTIAL
)
2300 csstart
= skb_checksum_start_offset(skb
);
2302 csstart
= skb_headlen(skb
);
2304 BUG_ON(csstart
> skb_headlen(skb
));
2306 skb_copy_from_linear_data(skb
, to
, csstart
);
2309 if (csstart
!= skb
->len
)
2310 csum
= skb_copy_and_csum_bits(skb
, csstart
, to
+ csstart
,
2311 skb
->len
- csstart
, 0);
2313 if (skb
->ip_summed
== CHECKSUM_PARTIAL
) {
2314 long csstuff
= csstart
+ skb
->csum_offset
;
2316 *((__sum16
*)(to
+ csstuff
)) = csum_fold(csum
);
2319 EXPORT_SYMBOL(skb_copy_and_csum_dev
);
2322 * skb_dequeue - remove from the head of the queue
2323 * @list: list to dequeue from
2325 * Remove the head of the list. The list lock is taken so the function
2326 * may be used safely with other locking list functions. The head item is
2327 * returned or %NULL if the list is empty.
2330 struct sk_buff
*skb_dequeue(struct sk_buff_head
*list
)
2332 unsigned long flags
;
2333 struct sk_buff
*result
;
2335 spin_lock_irqsave(&list
->lock
, flags
);
2336 result
= __skb_dequeue(list
);
2337 spin_unlock_irqrestore(&list
->lock
, flags
);
2340 EXPORT_SYMBOL(skb_dequeue
);
2343 * skb_dequeue_tail - remove from the tail of the queue
2344 * @list: list to dequeue from
2346 * Remove the tail of the list. The list lock is taken so the function
2347 * may be used safely with other locking list functions. The tail item is
2348 * returned or %NULL if the list is empty.
2350 struct sk_buff
*skb_dequeue_tail(struct sk_buff_head
*list
)
2352 unsigned long flags
;
2353 struct sk_buff
*result
;
2355 spin_lock_irqsave(&list
->lock
, flags
);
2356 result
= __skb_dequeue_tail(list
);
2357 spin_unlock_irqrestore(&list
->lock
, flags
);
2360 EXPORT_SYMBOL(skb_dequeue_tail
);
2363 * skb_queue_purge - empty a list
2364 * @list: list to empty
2366 * Delete all buffers on an &sk_buff list. Each buffer is removed from
2367 * the list and one reference dropped. This function takes the list
2368 * lock and is atomic with respect to other list locking functions.
2370 void skb_queue_purge(struct sk_buff_head
*list
)
2372 struct sk_buff
*skb
;
2373 while ((skb
= skb_dequeue(list
)) != NULL
)
2376 EXPORT_SYMBOL(skb_queue_purge
);
2379 * skb_queue_head - queue a buffer at the list head
2380 * @list: list to use
2381 * @newsk: buffer to queue
2383 * Queue a buffer at the start of the list. This function takes the
2384 * list lock and can be used safely with other locking &sk_buff functions
2387 * A buffer cannot be placed on two lists at the same time.
2389 void skb_queue_head(struct sk_buff_head
*list
, struct sk_buff
*newsk
)
2391 unsigned long flags
;
2393 spin_lock_irqsave(&list
->lock
, flags
);
2394 __skb_queue_head(list
, newsk
);
2395 spin_unlock_irqrestore(&list
->lock
, flags
);
2397 EXPORT_SYMBOL(skb_queue_head
);
2400 * skb_queue_tail - queue a buffer at the list tail
2401 * @list: list to use
2402 * @newsk: buffer to queue
2404 * Queue a buffer at the tail of the list. This function takes the
2405 * list lock and can be used safely with other locking &sk_buff functions
2408 * A buffer cannot be placed on two lists at the same time.
2410 void skb_queue_tail(struct sk_buff_head
*list
, struct sk_buff
*newsk
)
2412 unsigned long flags
;
2414 spin_lock_irqsave(&list
->lock
, flags
);
2415 __skb_queue_tail(list
, newsk
);
2416 spin_unlock_irqrestore(&list
->lock
, flags
);
2418 EXPORT_SYMBOL(skb_queue_tail
);
2421 * skb_unlink - remove a buffer from a list
2422 * @skb: buffer to remove
2423 * @list: list to use
2425 * Remove a packet from a list. The list locks are taken and this
2426 * function is atomic with respect to other list locked calls
2428 * You must know what list the SKB is on.
2430 void skb_unlink(struct sk_buff
*skb
, struct sk_buff_head
*list
)
2432 unsigned long flags
;
2434 spin_lock_irqsave(&list
->lock
, flags
);
2435 __skb_unlink(skb
, list
);
2436 spin_unlock_irqrestore(&list
->lock
, flags
);
2438 EXPORT_SYMBOL(skb_unlink
);
2441 * skb_append - append a buffer
2442 * @old: buffer to insert after
2443 * @newsk: buffer to insert
2444 * @list: list to use
2446 * Place a packet after a given packet in a list. The list locks are taken
2447 * and this function is atomic with respect to other list locked calls.
2448 * A buffer cannot be placed on two lists at the same time.
2450 void skb_append(struct sk_buff
*old
, struct sk_buff
*newsk
, struct sk_buff_head
*list
)
2452 unsigned long flags
;
2454 spin_lock_irqsave(&list
->lock
, flags
);
2455 __skb_queue_after(list
, old
, newsk
);
2456 spin_unlock_irqrestore(&list
->lock
, flags
);
2458 EXPORT_SYMBOL(skb_append
);
2461 * skb_insert - insert a buffer
2462 * @old: buffer to insert before
2463 * @newsk: buffer to insert
2464 * @list: list to use
2466 * Place a packet before a given packet in a list. The list locks are
2467 * taken and this function is atomic with respect to other list locked
2470 * A buffer cannot be placed on two lists at the same time.
2472 void skb_insert(struct sk_buff
*old
, struct sk_buff
*newsk
, struct sk_buff_head
*list
)
2474 unsigned long flags
;
2476 spin_lock_irqsave(&list
->lock
, flags
);
2477 __skb_insert(newsk
, old
->prev
, old
, list
);
2478 spin_unlock_irqrestore(&list
->lock
, flags
);
2480 EXPORT_SYMBOL(skb_insert
);
2482 static inline void skb_split_inside_header(struct sk_buff
*skb
,
2483 struct sk_buff
* skb1
,
2484 const u32 len
, const int pos
)
2488 skb_copy_from_linear_data_offset(skb
, len
, skb_put(skb1
, pos
- len
),
2490 /* And move data appendix as is. */
2491 for (i
= 0; i
< skb_shinfo(skb
)->nr_frags
; i
++)
2492 skb_shinfo(skb1
)->frags
[i
] = skb_shinfo(skb
)->frags
[i
];
2494 skb_shinfo(skb1
)->nr_frags
= skb_shinfo(skb
)->nr_frags
;
2495 skb_shinfo(skb
)->nr_frags
= 0;
2496 skb1
->data_len
= skb
->data_len
;
2497 skb1
->len
+= skb1
->data_len
;
2500 skb_set_tail_pointer(skb
, len
);
2503 static inline void skb_split_no_header(struct sk_buff
*skb
,
2504 struct sk_buff
* skb1
,
2505 const u32 len
, int pos
)
2508 const int nfrags
= skb_shinfo(skb
)->nr_frags
;
2510 skb_shinfo(skb
)->nr_frags
= 0;
2511 skb1
->len
= skb1
->data_len
= skb
->len
- len
;
2513 skb
->data_len
= len
- pos
;
2515 for (i
= 0; i
< nfrags
; i
++) {
2516 int size
= skb_frag_size(&skb_shinfo(skb
)->frags
[i
]);
2518 if (pos
+ size
> len
) {
2519 skb_shinfo(skb1
)->frags
[k
] = skb_shinfo(skb
)->frags
[i
];
2523 * We have two variants in this case:
2524 * 1. Move all the frag to the second
2525 * part, if it is possible. F.e.
2526 * this approach is mandatory for TUX,
2527 * where splitting is expensive.
2528 * 2. Split is accurately. We make this.
2530 skb_frag_ref(skb
, i
);
2531 skb_shinfo(skb1
)->frags
[0].page_offset
+= len
- pos
;
2532 skb_frag_size_sub(&skb_shinfo(skb1
)->frags
[0], len
- pos
);
2533 skb_frag_size_set(&skb_shinfo(skb
)->frags
[i
], len
- pos
);
2534 skb_shinfo(skb
)->nr_frags
++;
2538 skb_shinfo(skb
)->nr_frags
++;
2541 skb_shinfo(skb1
)->nr_frags
= k
;
2545 * skb_split - Split fragmented skb to two parts at length len.
2546 * @skb: the buffer to split
2547 * @skb1: the buffer to receive the second part
2548 * @len: new length for skb
2550 void skb_split(struct sk_buff
*skb
, struct sk_buff
*skb1
, const u32 len
)
2552 int pos
= skb_headlen(skb
);
2554 skb_shinfo(skb1
)->tx_flags
= skb_shinfo(skb
)->tx_flags
& SKBTX_SHARED_FRAG
;
2555 if (len
< pos
) /* Split line is inside header. */
2556 skb_split_inside_header(skb
, skb1
, len
, pos
);
2557 else /* Second chunk has no header, nothing to copy. */
2558 skb_split_no_header(skb
, skb1
, len
, pos
);
2560 EXPORT_SYMBOL(skb_split
);
2562 /* Shifting from/to a cloned skb is a no-go.
2564 * Caller cannot keep skb_shinfo related pointers past calling here!
2566 static int skb_prepare_for_shift(struct sk_buff
*skb
)
2568 return skb_cloned(skb
) && pskb_expand_head(skb
, 0, 0, GFP_ATOMIC
);
2572 * skb_shift - Shifts paged data partially from skb to another
2573 * @tgt: buffer into which tail data gets added
2574 * @skb: buffer from which the paged data comes from
2575 * @shiftlen: shift up to this many bytes
2577 * Attempts to shift up to shiftlen worth of bytes, which may be less than
2578 * the length of the skb, from skb to tgt. Returns number bytes shifted.
2579 * It's up to caller to free skb if everything was shifted.
2581 * If @tgt runs out of frags, the whole operation is aborted.
2583 * Skb cannot include anything else but paged data while tgt is allowed
2584 * to have non-paged data as well.
2586 * TODO: full sized shift could be optimized but that would need
2587 * specialized skb free'er to handle frags without up-to-date nr_frags.
2589 int skb_shift(struct sk_buff
*tgt
, struct sk_buff
*skb
, int shiftlen
)
2591 int from
, to
, merge
, todo
;
2592 struct skb_frag_struct
*fragfrom
, *fragto
;
2594 BUG_ON(shiftlen
> skb
->len
);
2595 BUG_ON(skb_headlen(skb
)); /* Would corrupt stream */
2599 to
= skb_shinfo(tgt
)->nr_frags
;
2600 fragfrom
= &skb_shinfo(skb
)->frags
[from
];
2602 /* Actual merge is delayed until the point when we know we can
2603 * commit all, so that we don't have to undo partial changes
2606 !skb_can_coalesce(tgt
, to
, skb_frag_page(fragfrom
),
2607 fragfrom
->page_offset
)) {
2612 todo
-= skb_frag_size(fragfrom
);
2614 if (skb_prepare_for_shift(skb
) ||
2615 skb_prepare_for_shift(tgt
))
2618 /* All previous frag pointers might be stale! */
2619 fragfrom
= &skb_shinfo(skb
)->frags
[from
];
2620 fragto
= &skb_shinfo(tgt
)->frags
[merge
];
2622 skb_frag_size_add(fragto
, shiftlen
);
2623 skb_frag_size_sub(fragfrom
, shiftlen
);
2624 fragfrom
->page_offset
+= shiftlen
;
2632 /* Skip full, not-fitting skb to avoid expensive operations */
2633 if ((shiftlen
== skb
->len
) &&
2634 (skb_shinfo(skb
)->nr_frags
- from
) > (MAX_SKB_FRAGS
- to
))
2637 if (skb_prepare_for_shift(skb
) || skb_prepare_for_shift(tgt
))
2640 while ((todo
> 0) && (from
< skb_shinfo(skb
)->nr_frags
)) {
2641 if (to
== MAX_SKB_FRAGS
)
2644 fragfrom
= &skb_shinfo(skb
)->frags
[from
];
2645 fragto
= &skb_shinfo(tgt
)->frags
[to
];
2647 if (todo
>= skb_frag_size(fragfrom
)) {
2648 *fragto
= *fragfrom
;
2649 todo
-= skb_frag_size(fragfrom
);
2654 __skb_frag_ref(fragfrom
);
2655 fragto
->page
= fragfrom
->page
;
2656 fragto
->page_offset
= fragfrom
->page_offset
;
2657 skb_frag_size_set(fragto
, todo
);
2659 fragfrom
->page_offset
+= todo
;
2660 skb_frag_size_sub(fragfrom
, todo
);
2668 /* Ready to "commit" this state change to tgt */
2669 skb_shinfo(tgt
)->nr_frags
= to
;
2672 fragfrom
= &skb_shinfo(skb
)->frags
[0];
2673 fragto
= &skb_shinfo(tgt
)->frags
[merge
];
2675 skb_frag_size_add(fragto
, skb_frag_size(fragfrom
));
2676 __skb_frag_unref(fragfrom
);
2679 /* Reposition in the original skb */
2681 while (from
< skb_shinfo(skb
)->nr_frags
)
2682 skb_shinfo(skb
)->frags
[to
++] = skb_shinfo(skb
)->frags
[from
++];
2683 skb_shinfo(skb
)->nr_frags
= to
;
2685 BUG_ON(todo
> 0 && !skb_shinfo(skb
)->nr_frags
);
2688 /* Most likely the tgt won't ever need its checksum anymore, skb on
2689 * the other hand might need it if it needs to be resent
2691 tgt
->ip_summed
= CHECKSUM_PARTIAL
;
2692 skb
->ip_summed
= CHECKSUM_PARTIAL
;
2694 /* Yak, is it really working this way? Some helper please? */
2695 skb
->len
-= shiftlen
;
2696 skb
->data_len
-= shiftlen
;
2697 skb
->truesize
-= shiftlen
;
2698 tgt
->len
+= shiftlen
;
2699 tgt
->data_len
+= shiftlen
;
2700 tgt
->truesize
+= shiftlen
;
2706 * skb_prepare_seq_read - Prepare a sequential read of skb data
2707 * @skb: the buffer to read
2708 * @from: lower offset of data to be read
2709 * @to: upper offset of data to be read
2710 * @st: state variable
2712 * Initializes the specified state variable. Must be called before
2713 * invoking skb_seq_read() for the first time.
2715 void skb_prepare_seq_read(struct sk_buff
*skb
, unsigned int from
,
2716 unsigned int to
, struct skb_seq_state
*st
)
2718 st
->lower_offset
= from
;
2719 st
->upper_offset
= to
;
2720 st
->root_skb
= st
->cur_skb
= skb
;
2721 st
->frag_idx
= st
->stepped_offset
= 0;
2722 st
->frag_data
= NULL
;
2724 EXPORT_SYMBOL(skb_prepare_seq_read
);
2727 * skb_seq_read - Sequentially read skb data
2728 * @consumed: number of bytes consumed by the caller so far
2729 * @data: destination pointer for data to be returned
2730 * @st: state variable
2732 * Reads a block of skb data at @consumed relative to the
2733 * lower offset specified to skb_prepare_seq_read(). Assigns
2734 * the head of the data block to @data and returns the length
2735 * of the block or 0 if the end of the skb data or the upper
2736 * offset has been reached.
2738 * The caller is not required to consume all of the data
2739 * returned, i.e. @consumed is typically set to the number
2740 * of bytes already consumed and the next call to
2741 * skb_seq_read() will return the remaining part of the block.
2743 * Note 1: The size of each block of data returned can be arbitrary,
2744 * this limitation is the cost for zerocopy sequential
2745 * reads of potentially non linear data.
2747 * Note 2: Fragment lists within fragments are not implemented
2748 * at the moment, state->root_skb could be replaced with
2749 * a stack for this purpose.
2751 unsigned int skb_seq_read(unsigned int consumed
, const u8
**data
,
2752 struct skb_seq_state
*st
)
2754 unsigned int block_limit
, abs_offset
= consumed
+ st
->lower_offset
;
2757 if (unlikely(abs_offset
>= st
->upper_offset
)) {
2758 if (st
->frag_data
) {
2759 kunmap_atomic(st
->frag_data
);
2760 st
->frag_data
= NULL
;
2766 block_limit
= skb_headlen(st
->cur_skb
) + st
->stepped_offset
;
2768 if (abs_offset
< block_limit
&& !st
->frag_data
) {
2769 *data
= st
->cur_skb
->data
+ (abs_offset
- st
->stepped_offset
);
2770 return block_limit
- abs_offset
;
2773 if (st
->frag_idx
== 0 && !st
->frag_data
)
2774 st
->stepped_offset
+= skb_headlen(st
->cur_skb
);
2776 while (st
->frag_idx
< skb_shinfo(st
->cur_skb
)->nr_frags
) {
2777 frag
= &skb_shinfo(st
->cur_skb
)->frags
[st
->frag_idx
];
2778 block_limit
= skb_frag_size(frag
) + st
->stepped_offset
;
2780 if (abs_offset
< block_limit
) {
2782 st
->frag_data
= kmap_atomic(skb_frag_page(frag
));
2784 *data
= (u8
*) st
->frag_data
+ frag
->page_offset
+
2785 (abs_offset
- st
->stepped_offset
);
2787 return block_limit
- abs_offset
;
2790 if (st
->frag_data
) {
2791 kunmap_atomic(st
->frag_data
);
2792 st
->frag_data
= NULL
;
2796 st
->stepped_offset
+= skb_frag_size(frag
);
2799 if (st
->frag_data
) {
2800 kunmap_atomic(st
->frag_data
);
2801 st
->frag_data
= NULL
;
2804 if (st
->root_skb
== st
->cur_skb
&& skb_has_frag_list(st
->root_skb
)) {
2805 st
->cur_skb
= skb_shinfo(st
->root_skb
)->frag_list
;
2808 } else if (st
->cur_skb
->next
) {
2809 st
->cur_skb
= st
->cur_skb
->next
;
2816 EXPORT_SYMBOL(skb_seq_read
);
2819 * skb_abort_seq_read - Abort a sequential read of skb data
2820 * @st: state variable
2822 * Must be called if skb_seq_read() was not called until it
2825 void skb_abort_seq_read(struct skb_seq_state
*st
)
2828 kunmap_atomic(st
->frag_data
);
2830 EXPORT_SYMBOL(skb_abort_seq_read
);
2832 #define TS_SKB_CB(state) ((struct skb_seq_state *) &((state)->cb))
2834 static unsigned int skb_ts_get_next_block(unsigned int offset
, const u8
**text
,
2835 struct ts_config
*conf
,
2836 struct ts_state
*state
)
2838 return skb_seq_read(offset
, text
, TS_SKB_CB(state
));
2841 static void skb_ts_finish(struct ts_config
*conf
, struct ts_state
*state
)
2843 skb_abort_seq_read(TS_SKB_CB(state
));
2847 * skb_find_text - Find a text pattern in skb data
2848 * @skb: the buffer to look in
2849 * @from: search offset
2851 * @config: textsearch configuration
2853 * Finds a pattern in the skb data according to the specified
2854 * textsearch configuration. Use textsearch_next() to retrieve
2855 * subsequent occurrences of the pattern. Returns the offset
2856 * to the first occurrence or UINT_MAX if no match was found.
2858 unsigned int skb_find_text(struct sk_buff
*skb
, unsigned int from
,
2859 unsigned int to
, struct ts_config
*config
)
2861 struct ts_state state
;
2864 config
->get_next_block
= skb_ts_get_next_block
;
2865 config
->finish
= skb_ts_finish
;
2867 skb_prepare_seq_read(skb
, from
, to
, TS_SKB_CB(&state
));
2869 ret
= textsearch_find(config
, &state
);
2870 return (ret
<= to
- from
? ret
: UINT_MAX
);
2872 EXPORT_SYMBOL(skb_find_text
);
2875 * skb_append_datato_frags - append the user data to a skb
2876 * @sk: sock structure
2877 * @skb: skb structure to be appended with user data.
2878 * @getfrag: call back function to be used for getting the user data
2879 * @from: pointer to user message iov
2880 * @length: length of the iov message
2882 * Description: This procedure append the user data in the fragment part
2883 * of the skb if any page alloc fails user this procedure returns -ENOMEM
2885 int skb_append_datato_frags(struct sock
*sk
, struct sk_buff
*skb
,
2886 int (*getfrag
)(void *from
, char *to
, int offset
,
2887 int len
, int odd
, struct sk_buff
*skb
),
2888 void *from
, int length
)
2890 int frg_cnt
= skb_shinfo(skb
)->nr_frags
;
2894 struct page_frag
*pfrag
= ¤t
->task_frag
;
2897 /* Return error if we don't have space for new frag */
2898 if (frg_cnt
>= MAX_SKB_FRAGS
)
2901 if (!sk_page_frag_refill(sk
, pfrag
))
2904 /* copy the user data to page */
2905 copy
= min_t(int, length
, pfrag
->size
- pfrag
->offset
);
2907 ret
= getfrag(from
, page_address(pfrag
->page
) + pfrag
->offset
,
2908 offset
, copy
, 0, skb
);
2912 /* copy was successful so update the size parameters */
2913 skb_fill_page_desc(skb
, frg_cnt
, pfrag
->page
, pfrag
->offset
,
2916 pfrag
->offset
+= copy
;
2917 get_page(pfrag
->page
);
2919 skb
->truesize
+= copy
;
2920 atomic_add(copy
, &sk
->sk_wmem_alloc
);
2922 skb
->data_len
+= copy
;
2926 } while (length
> 0);
2930 EXPORT_SYMBOL(skb_append_datato_frags
);
2932 int skb_append_pagefrags(struct sk_buff
*skb
, struct page
*page
,
2933 int offset
, size_t size
)
2935 int i
= skb_shinfo(skb
)->nr_frags
;
2937 if (skb_can_coalesce(skb
, i
, page
, offset
)) {
2938 skb_frag_size_add(&skb_shinfo(skb
)->frags
[i
- 1], size
);
2939 } else if (i
< MAX_SKB_FRAGS
) {
2941 skb_fill_page_desc(skb
, i
, page
, offset
, size
);
2948 EXPORT_SYMBOL_GPL(skb_append_pagefrags
);
2951 * skb_pull_rcsum - pull skb and update receive checksum
2952 * @skb: buffer to update
2953 * @len: length of data pulled
2955 * This function performs an skb_pull on the packet and updates
2956 * the CHECKSUM_COMPLETE checksum. It should be used on
2957 * receive path processing instead of skb_pull unless you know
2958 * that the checksum difference is zero (e.g., a valid IP header)
2959 * or you are setting ip_summed to CHECKSUM_NONE.
2961 unsigned char *skb_pull_rcsum(struct sk_buff
*skb
, unsigned int len
)
2963 unsigned char *data
= skb
->data
;
2965 BUG_ON(len
> skb
->len
);
2966 __skb_pull(skb
, len
);
2967 skb_postpull_rcsum(skb
, data
, len
);
2970 EXPORT_SYMBOL_GPL(skb_pull_rcsum
);
2973 * skb_segment - Perform protocol segmentation on skb.
2974 * @head_skb: buffer to segment
2975 * @features: features for the output path (see dev->features)
2977 * This function performs segmentation on the given skb. It returns
2978 * a pointer to the first in a list of new skbs for the segments.
2979 * In case of error it returns ERR_PTR(err).
2981 struct sk_buff
*skb_segment(struct sk_buff
*head_skb
,
2982 netdev_features_t features
)
2984 struct sk_buff
*segs
= NULL
;
2985 struct sk_buff
*tail
= NULL
;
2986 struct sk_buff
*list_skb
= skb_shinfo(head_skb
)->frag_list
;
2987 skb_frag_t
*frag
= skb_shinfo(head_skb
)->frags
;
2988 unsigned int mss
= skb_shinfo(head_skb
)->gso_size
;
2989 unsigned int doffset
= head_skb
->data
- skb_mac_header(head_skb
);
2990 struct sk_buff
*frag_skb
= head_skb
;
2991 unsigned int offset
= doffset
;
2992 unsigned int tnl_hlen
= skb_tnl_header_len(head_skb
);
2993 unsigned int headroom
;
2997 int sg
= !!(features
& NETIF_F_SG
);
2998 int nfrags
= skb_shinfo(head_skb
)->nr_frags
;
3004 __skb_push(head_skb
, doffset
);
3005 proto
= skb_network_protocol(head_skb
, &dummy
);
3006 if (unlikely(!proto
))
3007 return ERR_PTR(-EINVAL
);
3009 csum
= !head_skb
->encap_hdr_csum
&&
3010 !!can_checksum_protocol(features
, proto
);
3012 headroom
= skb_headroom(head_skb
);
3013 pos
= skb_headlen(head_skb
);
3016 struct sk_buff
*nskb
;
3017 skb_frag_t
*nskb_frag
;
3021 len
= head_skb
->len
- offset
;
3025 hsize
= skb_headlen(head_skb
) - offset
;
3028 if (hsize
> len
|| !sg
)
3031 if (!hsize
&& i
>= nfrags
&& skb_headlen(list_skb
) &&
3032 (skb_headlen(list_skb
) == len
|| sg
)) {
3033 BUG_ON(skb_headlen(list_skb
) > len
);
3036 nfrags
= skb_shinfo(list_skb
)->nr_frags
;
3037 frag
= skb_shinfo(list_skb
)->frags
;
3038 frag_skb
= list_skb
;
3039 pos
+= skb_headlen(list_skb
);
3041 while (pos
< offset
+ len
) {
3042 BUG_ON(i
>= nfrags
);
3044 size
= skb_frag_size(frag
);
3045 if (pos
+ size
> offset
+ len
)
3053 nskb
= skb_clone(list_skb
, GFP_ATOMIC
);
3054 list_skb
= list_skb
->next
;
3056 if (unlikely(!nskb
))
3059 if (unlikely(pskb_trim(nskb
, len
))) {
3064 hsize
= skb_end_offset(nskb
);
3065 if (skb_cow_head(nskb
, doffset
+ headroom
)) {
3070 nskb
->truesize
+= skb_end_offset(nskb
) - hsize
;
3071 skb_release_head_state(nskb
);
3072 __skb_push(nskb
, doffset
);
3074 nskb
= __alloc_skb(hsize
+ doffset
+ headroom
,
3075 GFP_ATOMIC
, skb_alloc_rx_flag(head_skb
),
3078 if (unlikely(!nskb
))
3081 skb_reserve(nskb
, headroom
);
3082 __skb_put(nskb
, doffset
);
3091 __copy_skb_header(nskb
, head_skb
);
3093 skb_headers_offset_update(nskb
, skb_headroom(nskb
) - headroom
);
3094 skb_reset_mac_len(nskb
);
3096 skb_copy_from_linear_data_offset(head_skb
, -tnl_hlen
,
3097 nskb
->data
- tnl_hlen
,
3098 doffset
+ tnl_hlen
);
3100 if (nskb
->len
== len
+ doffset
)
3101 goto perform_csum_check
;
3103 if (!sg
&& !nskb
->remcsum_offload
) {
3104 nskb
->ip_summed
= CHECKSUM_NONE
;
3105 nskb
->csum
= skb_copy_and_csum_bits(head_skb
, offset
,
3108 SKB_GSO_CB(nskb
)->csum_start
=
3109 skb_headroom(nskb
) + doffset
;
3113 nskb_frag
= skb_shinfo(nskb
)->frags
;
3115 skb_copy_from_linear_data_offset(head_skb
, offset
,
3116 skb_put(nskb
, hsize
), hsize
);
3118 skb_shinfo(nskb
)->tx_flags
= skb_shinfo(head_skb
)->tx_flags
&
3121 while (pos
< offset
+ len
) {
3123 BUG_ON(skb_headlen(list_skb
));
3126 nfrags
= skb_shinfo(list_skb
)->nr_frags
;
3127 frag
= skb_shinfo(list_skb
)->frags
;
3128 frag_skb
= list_skb
;
3132 list_skb
= list_skb
->next
;
3135 if (unlikely(skb_shinfo(nskb
)->nr_frags
>=
3137 net_warn_ratelimited(
3138 "skb_segment: too many frags: %u %u\n",
3143 if (unlikely(skb_orphan_frags(frag_skb
, GFP_ATOMIC
)))
3147 __skb_frag_ref(nskb_frag
);
3148 size
= skb_frag_size(nskb_frag
);
3151 nskb_frag
->page_offset
+= offset
- pos
;
3152 skb_frag_size_sub(nskb_frag
, offset
- pos
);
3155 skb_shinfo(nskb
)->nr_frags
++;
3157 if (pos
+ size
<= offset
+ len
) {
3162 skb_frag_size_sub(nskb_frag
, pos
+ size
- (offset
+ len
));
3170 nskb
->data_len
= len
- hsize
;
3171 nskb
->len
+= nskb
->data_len
;
3172 nskb
->truesize
+= nskb
->data_len
;
3175 if (!csum
&& !nskb
->remcsum_offload
) {
3176 nskb
->csum
= skb_checksum(nskb
, doffset
,
3177 nskb
->len
- doffset
, 0);
3178 nskb
->ip_summed
= CHECKSUM_NONE
;
3179 SKB_GSO_CB(nskb
)->csum_start
=
3180 skb_headroom(nskb
) + doffset
;
3182 } while ((offset
+= len
) < head_skb
->len
);
3184 /* Some callers want to get the end of the list.
3185 * Put it in segs->prev to avoid walking the list.
3186 * (see validate_xmit_skb_list() for example)
3190 /* Following permits correct backpressure, for protocols
3191 * using skb_set_owner_w().
3192 * Idea is to tranfert ownership from head_skb to last segment.
3194 if (head_skb
->destructor
== sock_wfree
) {
3195 swap(tail
->truesize
, head_skb
->truesize
);
3196 swap(tail
->destructor
, head_skb
->destructor
);
3197 swap(tail
->sk
, head_skb
->sk
);
3202 kfree_skb_list(segs
);
3203 return ERR_PTR(err
);
3205 EXPORT_SYMBOL_GPL(skb_segment
);
3207 int skb_gro_receive(struct sk_buff
**head
, struct sk_buff
*skb
)
3209 struct skb_shared_info
*pinfo
, *skbinfo
= skb_shinfo(skb
);
3210 unsigned int offset
= skb_gro_offset(skb
);
3211 unsigned int headlen
= skb_headlen(skb
);
3212 unsigned int len
= skb_gro_len(skb
);
3213 struct sk_buff
*lp
, *p
= *head
;
3214 unsigned int delta_truesize
;
3216 if (unlikely(p
->len
+ len
>= 65536))
3219 lp
= NAPI_GRO_CB(p
)->last
;
3220 pinfo
= skb_shinfo(lp
);
3222 if (headlen
<= offset
) {
3225 int i
= skbinfo
->nr_frags
;
3226 int nr_frags
= pinfo
->nr_frags
+ i
;
3228 if (nr_frags
> MAX_SKB_FRAGS
)
3232 pinfo
->nr_frags
= nr_frags
;
3233 skbinfo
->nr_frags
= 0;
3235 frag
= pinfo
->frags
+ nr_frags
;
3236 frag2
= skbinfo
->frags
+ i
;
3241 frag
->page_offset
+= offset
;
3242 skb_frag_size_sub(frag
, offset
);
3244 /* all fragments truesize : remove (head size + sk_buff) */
3245 delta_truesize
= skb
->truesize
-
3246 SKB_TRUESIZE(skb_end_offset(skb
));
3248 skb
->truesize
-= skb
->data_len
;
3249 skb
->len
-= skb
->data_len
;
3252 NAPI_GRO_CB(skb
)->free
= NAPI_GRO_FREE
;
3254 } else if (skb
->head_frag
) {
3255 int nr_frags
= pinfo
->nr_frags
;
3256 skb_frag_t
*frag
= pinfo
->frags
+ nr_frags
;
3257 struct page
*page
= virt_to_head_page(skb
->head
);
3258 unsigned int first_size
= headlen
- offset
;
3259 unsigned int first_offset
;
3261 if (nr_frags
+ 1 + skbinfo
->nr_frags
> MAX_SKB_FRAGS
)
3264 first_offset
= skb
->data
-
3265 (unsigned char *)page_address(page
) +
3268 pinfo
->nr_frags
= nr_frags
+ 1 + skbinfo
->nr_frags
;
3270 frag
->page
.p
= page
;
3271 frag
->page_offset
= first_offset
;
3272 skb_frag_size_set(frag
, first_size
);
3274 memcpy(frag
+ 1, skbinfo
->frags
, sizeof(*frag
) * skbinfo
->nr_frags
);
3275 /* We dont need to clear skbinfo->nr_frags here */
3277 delta_truesize
= skb
->truesize
- SKB_DATA_ALIGN(sizeof(struct sk_buff
));
3278 NAPI_GRO_CB(skb
)->free
= NAPI_GRO_FREE_STOLEN_HEAD
;
3283 delta_truesize
= skb
->truesize
;
3284 if (offset
> headlen
) {
3285 unsigned int eat
= offset
- headlen
;
3287 skbinfo
->frags
[0].page_offset
+= eat
;
3288 skb_frag_size_sub(&skbinfo
->frags
[0], eat
);
3289 skb
->data_len
-= eat
;
3294 __skb_pull(skb
, offset
);
3296 if (NAPI_GRO_CB(p
)->last
== p
)
3297 skb_shinfo(p
)->frag_list
= skb
;
3299 NAPI_GRO_CB(p
)->last
->next
= skb
;
3300 NAPI_GRO_CB(p
)->last
= skb
;
3301 __skb_header_release(skb
);
3305 NAPI_GRO_CB(p
)->count
++;
3307 p
->truesize
+= delta_truesize
;
3310 lp
->data_len
+= len
;
3311 lp
->truesize
+= delta_truesize
;
3314 NAPI_GRO_CB(skb
)->same_flow
= 1;
3318 void __init
skb_init(void)
3320 skbuff_head_cache
= kmem_cache_create("skbuff_head_cache",
3321 sizeof(struct sk_buff
),
3323 SLAB_HWCACHE_ALIGN
|SLAB_PANIC
,
3325 skbuff_fclone_cache
= kmem_cache_create("skbuff_fclone_cache",
3326 sizeof(struct sk_buff_fclones
),
3328 SLAB_HWCACHE_ALIGN
|SLAB_PANIC
,
3333 * skb_to_sgvec - Fill a scatter-gather list from a socket buffer
3334 * @skb: Socket buffer containing the buffers to be mapped
3335 * @sg: The scatter-gather list to map into
3336 * @offset: The offset into the buffer's contents to start mapping
3337 * @len: Length of buffer space to be mapped
3339 * Fill the specified scatter-gather list with mappings/pointers into a
3340 * region of the buffer space attached to a socket buffer.
3343 __skb_to_sgvec(struct sk_buff
*skb
, struct scatterlist
*sg
, int offset
, int len
)
3345 int start
= skb_headlen(skb
);
3346 int i
, copy
= start
- offset
;
3347 struct sk_buff
*frag_iter
;
3353 sg_set_buf(sg
, skb
->data
+ offset
, copy
);
3355 if ((len
-= copy
) == 0)
3360 for (i
= 0; i
< skb_shinfo(skb
)->nr_frags
; i
++) {
3363 WARN_ON(start
> offset
+ len
);
3365 end
= start
+ skb_frag_size(&skb_shinfo(skb
)->frags
[i
]);
3366 if ((copy
= end
- offset
) > 0) {
3367 skb_frag_t
*frag
= &skb_shinfo(skb
)->frags
[i
];
3371 sg_set_page(&sg
[elt
], skb_frag_page(frag
), copy
,
3372 frag
->page_offset
+offset
-start
);
3381 skb_walk_frags(skb
, frag_iter
) {
3384 WARN_ON(start
> offset
+ len
);
3386 end
= start
+ frag_iter
->len
;
3387 if ((copy
= end
- offset
) > 0) {
3390 elt
+= __skb_to_sgvec(frag_iter
, sg
+elt
, offset
- start
,
3392 if ((len
-= copy
) == 0)
3402 /* As compared with skb_to_sgvec, skb_to_sgvec_nomark only map skb to given
3403 * sglist without mark the sg which contain last skb data as the end.
3404 * So the caller can mannipulate sg list as will when padding new data after
3405 * the first call without calling sg_unmark_end to expend sg list.
3407 * Scenario to use skb_to_sgvec_nomark:
3409 * 2. skb_to_sgvec_nomark(payload1)
3410 * 3. skb_to_sgvec_nomark(payload2)
3412 * This is equivalent to:
3414 * 2. skb_to_sgvec(payload1)
3416 * 4. skb_to_sgvec(payload2)
3418 * When mapping mutilple payload conditionally, skb_to_sgvec_nomark
3419 * is more preferable.
3421 int skb_to_sgvec_nomark(struct sk_buff
*skb
, struct scatterlist
*sg
,
3422 int offset
, int len
)
3424 return __skb_to_sgvec(skb
, sg
, offset
, len
);
3426 EXPORT_SYMBOL_GPL(skb_to_sgvec_nomark
);
3428 int skb_to_sgvec(struct sk_buff
*skb
, struct scatterlist
*sg
, int offset
, int len
)
3430 int nsg
= __skb_to_sgvec(skb
, sg
, offset
, len
);
3432 sg_mark_end(&sg
[nsg
- 1]);
3436 EXPORT_SYMBOL_GPL(skb_to_sgvec
);
3439 * skb_cow_data - Check that a socket buffer's data buffers are writable
3440 * @skb: The socket buffer to check.
3441 * @tailbits: Amount of trailing space to be added
3442 * @trailer: Returned pointer to the skb where the @tailbits space begins
3444 * Make sure that the data buffers attached to a socket buffer are
3445 * writable. If they are not, private copies are made of the data buffers
3446 * and the socket buffer is set to use these instead.
3448 * If @tailbits is given, make sure that there is space to write @tailbits
3449 * bytes of data beyond current end of socket buffer. @trailer will be
3450 * set to point to the skb in which this space begins.
3452 * The number of scatterlist elements required to completely map the
3453 * COW'd and extended socket buffer will be returned.
3455 int skb_cow_data(struct sk_buff
*skb
, int tailbits
, struct sk_buff
**trailer
)
3459 struct sk_buff
*skb1
, **skb_p
;
3461 /* If skb is cloned or its head is paged, reallocate
3462 * head pulling out all the pages (pages are considered not writable
3463 * at the moment even if they are anonymous).
3465 if ((skb_cloned(skb
) || skb_shinfo(skb
)->nr_frags
) &&
3466 __pskb_pull_tail(skb
, skb_pagelen(skb
)-skb_headlen(skb
)) == NULL
)
3469 /* Easy case. Most of packets will go this way. */
3470 if (!skb_has_frag_list(skb
)) {
3471 /* A little of trouble, not enough of space for trailer.
3472 * This should not happen, when stack is tuned to generate
3473 * good frames. OK, on miss we reallocate and reserve even more
3474 * space, 128 bytes is fair. */
3476 if (skb_tailroom(skb
) < tailbits
&&
3477 pskb_expand_head(skb
, 0, tailbits
-skb_tailroom(skb
)+128, GFP_ATOMIC
))
3485 /* Misery. We are in troubles, going to mincer fragments... */
3488 skb_p
= &skb_shinfo(skb
)->frag_list
;
3491 while ((skb1
= *skb_p
) != NULL
) {
3494 /* The fragment is partially pulled by someone,
3495 * this can happen on input. Copy it and everything
3498 if (skb_shared(skb1
))
3501 /* If the skb is the last, worry about trailer. */
3503 if (skb1
->next
== NULL
&& tailbits
) {
3504 if (skb_shinfo(skb1
)->nr_frags
||
3505 skb_has_frag_list(skb1
) ||
3506 skb_tailroom(skb1
) < tailbits
)
3507 ntail
= tailbits
+ 128;
3513 skb_shinfo(skb1
)->nr_frags
||
3514 skb_has_frag_list(skb1
)) {
3515 struct sk_buff
*skb2
;
3517 /* Fuck, we are miserable poor guys... */
3519 skb2
= skb_copy(skb1
, GFP_ATOMIC
);
3521 skb2
= skb_copy_expand(skb1
,
3525 if (unlikely(skb2
== NULL
))
3529 skb_set_owner_w(skb2
, skb1
->sk
);
3531 /* Looking around. Are we still alive?
3532 * OK, link new skb, drop old one */
3534 skb2
->next
= skb1
->next
;
3541 skb_p
= &skb1
->next
;
3546 EXPORT_SYMBOL_GPL(skb_cow_data
);
3548 static void sock_rmem_free(struct sk_buff
*skb
)
3550 struct sock
*sk
= skb
->sk
;
3552 atomic_sub(skb
->truesize
, &sk
->sk_rmem_alloc
);
3556 * Note: We dont mem charge error packets (no sk_forward_alloc changes)
3558 int sock_queue_err_skb(struct sock
*sk
, struct sk_buff
*skb
)
3560 if (atomic_read(&sk
->sk_rmem_alloc
) + skb
->truesize
>=
3561 (unsigned int)sk
->sk_rcvbuf
)
3566 skb
->destructor
= sock_rmem_free
;
3567 atomic_add(skb
->truesize
, &sk
->sk_rmem_alloc
);
3569 /* before exiting rcu section, make sure dst is refcounted */
3572 skb_queue_tail(&sk
->sk_error_queue
, skb
);
3573 if (!sock_flag(sk
, SOCK_DEAD
))
3574 sk
->sk_data_ready(sk
);
3577 EXPORT_SYMBOL(sock_queue_err_skb
);
3579 struct sk_buff
*sock_dequeue_err_skb(struct sock
*sk
)
3581 struct sk_buff_head
*q
= &sk
->sk_error_queue
;
3582 struct sk_buff
*skb
, *skb_next
;
3583 unsigned long flags
;
3586 spin_lock_irqsave(&q
->lock
, flags
);
3587 skb
= __skb_dequeue(q
);
3588 if (skb
&& (skb_next
= skb_peek(q
)))
3589 err
= SKB_EXT_ERR(skb_next
)->ee
.ee_errno
;
3590 spin_unlock_irqrestore(&q
->lock
, flags
);
3594 sk
->sk_error_report(sk
);
3598 EXPORT_SYMBOL(sock_dequeue_err_skb
);
3601 * skb_clone_sk - create clone of skb, and take reference to socket
3602 * @skb: the skb to clone
3604 * This function creates a clone of a buffer that holds a reference on
3605 * sk_refcnt. Buffers created via this function are meant to be
3606 * returned using sock_queue_err_skb, or free via kfree_skb.
3608 * When passing buffers allocated with this function to sock_queue_err_skb
3609 * it is necessary to wrap the call with sock_hold/sock_put in order to
3610 * prevent the socket from being released prior to being enqueued on
3611 * the sk_error_queue.
3613 struct sk_buff
*skb_clone_sk(struct sk_buff
*skb
)
3615 struct sock
*sk
= skb
->sk
;
3616 struct sk_buff
*clone
;
3618 if (!sk
|| !atomic_inc_not_zero(&sk
->sk_refcnt
))
3621 clone
= skb_clone(skb
, GFP_ATOMIC
);
3628 clone
->destructor
= sock_efree
;
3632 EXPORT_SYMBOL(skb_clone_sk
);
3634 static void __skb_complete_tx_timestamp(struct sk_buff
*skb
,
3638 struct sock_exterr_skb
*serr
;
3641 serr
= SKB_EXT_ERR(skb
);
3642 memset(serr
, 0, sizeof(*serr
));
3643 serr
->ee
.ee_errno
= ENOMSG
;
3644 serr
->ee
.ee_origin
= SO_EE_ORIGIN_TIMESTAMPING
;
3645 serr
->ee
.ee_info
= tstype
;
3646 if (sk
->sk_tsflags
& SOF_TIMESTAMPING_OPT_ID
) {
3647 serr
->ee
.ee_data
= skb_shinfo(skb
)->tskey
;
3648 if (sk
->sk_protocol
== IPPROTO_TCP
&&
3649 sk
->sk_type
== SOCK_STREAM
)
3650 serr
->ee
.ee_data
-= sk
->sk_tskey
;
3653 err
= sock_queue_err_skb(sk
, skb
);
3659 static bool skb_may_tx_timestamp(struct sock
*sk
, bool tsonly
)
3663 if (likely(sysctl_tstamp_allow_data
|| tsonly
))
3666 read_lock_bh(&sk
->sk_callback_lock
);
3667 ret
= sk
->sk_socket
&& sk
->sk_socket
->file
&&
3668 file_ns_capable(sk
->sk_socket
->file
, &init_user_ns
, CAP_NET_RAW
);
3669 read_unlock_bh(&sk
->sk_callback_lock
);
3673 void skb_complete_tx_timestamp(struct sk_buff
*skb
,
3674 struct skb_shared_hwtstamps
*hwtstamps
)
3676 struct sock
*sk
= skb
->sk
;
3678 if (!skb_may_tx_timestamp(sk
, false))
3681 /* take a reference to prevent skb_orphan() from freeing the socket */
3684 *skb_hwtstamps(skb
) = *hwtstamps
;
3685 __skb_complete_tx_timestamp(skb
, sk
, SCM_TSTAMP_SND
);
3689 EXPORT_SYMBOL_GPL(skb_complete_tx_timestamp
);
3691 void __skb_tstamp_tx(struct sk_buff
*orig_skb
,
3692 struct skb_shared_hwtstamps
*hwtstamps
,
3693 struct sock
*sk
, int tstype
)
3695 struct sk_buff
*skb
;
3701 tsonly
= sk
->sk_tsflags
& SOF_TIMESTAMPING_OPT_TSONLY
;
3702 if (!skb_may_tx_timestamp(sk
, tsonly
))
3706 skb
= alloc_skb(0, GFP_ATOMIC
);
3708 skb
= skb_clone(orig_skb
, GFP_ATOMIC
);
3713 skb_shinfo(skb
)->tx_flags
= skb_shinfo(orig_skb
)->tx_flags
;
3714 skb_shinfo(skb
)->tskey
= skb_shinfo(orig_skb
)->tskey
;
3718 *skb_hwtstamps(skb
) = *hwtstamps
;
3720 skb
->tstamp
= ktime_get_real();
3722 __skb_complete_tx_timestamp(skb
, sk
, tstype
);
3724 EXPORT_SYMBOL_GPL(__skb_tstamp_tx
);
3726 void skb_tstamp_tx(struct sk_buff
*orig_skb
,
3727 struct skb_shared_hwtstamps
*hwtstamps
)
3729 return __skb_tstamp_tx(orig_skb
, hwtstamps
, orig_skb
->sk
,
3732 EXPORT_SYMBOL_GPL(skb_tstamp_tx
);
3734 void skb_complete_wifi_ack(struct sk_buff
*skb
, bool acked
)
3736 struct sock
*sk
= skb
->sk
;
3737 struct sock_exterr_skb
*serr
;
3740 skb
->wifi_acked_valid
= 1;
3741 skb
->wifi_acked
= acked
;
3743 serr
= SKB_EXT_ERR(skb
);
3744 memset(serr
, 0, sizeof(*serr
));
3745 serr
->ee
.ee_errno
= ENOMSG
;
3746 serr
->ee
.ee_origin
= SO_EE_ORIGIN_TXSTATUS
;
3748 /* take a reference to prevent skb_orphan() from freeing the socket */
3751 err
= sock_queue_err_skb(sk
, skb
);
3757 EXPORT_SYMBOL_GPL(skb_complete_wifi_ack
);
3760 * skb_partial_csum_set - set up and verify partial csum values for packet
3761 * @skb: the skb to set
3762 * @start: the number of bytes after skb->data to start checksumming.
3763 * @off: the offset from start to place the checksum.
3765 * For untrusted partially-checksummed packets, we need to make sure the values
3766 * for skb->csum_start and skb->csum_offset are valid so we don't oops.
3768 * This function checks and sets those values and skb->ip_summed: if this
3769 * returns false you should drop the packet.
3771 bool skb_partial_csum_set(struct sk_buff
*skb
, u16 start
, u16 off
)
3773 if (unlikely(start
> skb_headlen(skb
)) ||
3774 unlikely((int)start
+ off
> skb_headlen(skb
) - 2)) {
3775 net_warn_ratelimited("bad partial csum: csum=%u/%u len=%u\n",
3776 start
, off
, skb_headlen(skb
));
3779 skb
->ip_summed
= CHECKSUM_PARTIAL
;
3780 skb
->csum_start
= skb_headroom(skb
) + start
;
3781 skb
->csum_offset
= off
;
3782 skb_set_transport_header(skb
, start
);
3785 EXPORT_SYMBOL_GPL(skb_partial_csum_set
);
3787 static int skb_maybe_pull_tail(struct sk_buff
*skb
, unsigned int len
,
3790 if (skb_headlen(skb
) >= len
)
3793 /* If we need to pullup then pullup to the max, so we
3794 * won't need to do it again.
3799 if (__pskb_pull_tail(skb
, max
- skb_headlen(skb
)) == NULL
)
3802 if (skb_headlen(skb
) < len
)
3808 #define MAX_TCP_HDR_LEN (15 * 4)
3810 static __sum16
*skb_checksum_setup_ip(struct sk_buff
*skb
,
3811 typeof(IPPROTO_IP
) proto
,
3818 err
= skb_maybe_pull_tail(skb
, off
+ sizeof(struct tcphdr
),
3819 off
+ MAX_TCP_HDR_LEN
);
3820 if (!err
&& !skb_partial_csum_set(skb
, off
,
3821 offsetof(struct tcphdr
,
3824 return err
? ERR_PTR(err
) : &tcp_hdr(skb
)->check
;
3827 err
= skb_maybe_pull_tail(skb
, off
+ sizeof(struct udphdr
),
3828 off
+ sizeof(struct udphdr
));
3829 if (!err
&& !skb_partial_csum_set(skb
, off
,
3830 offsetof(struct udphdr
,
3833 return err
? ERR_PTR(err
) : &udp_hdr(skb
)->check
;
3836 return ERR_PTR(-EPROTO
);
3839 /* This value should be large enough to cover a tagged ethernet header plus
3840 * maximally sized IP and TCP or UDP headers.
3842 #define MAX_IP_HDR_LEN 128
3844 static int skb_checksum_setup_ipv4(struct sk_buff
*skb
, bool recalculate
)
3853 err
= skb_maybe_pull_tail(skb
,
3854 sizeof(struct iphdr
),
3859 if (ip_hdr(skb
)->frag_off
& htons(IP_OFFSET
| IP_MF
))
3862 off
= ip_hdrlen(skb
);
3869 csum
= skb_checksum_setup_ip(skb
, ip_hdr(skb
)->protocol
, off
);
3871 return PTR_ERR(csum
);
3874 *csum
= ~csum_tcpudp_magic(ip_hdr(skb
)->saddr
,
3877 ip_hdr(skb
)->protocol
, 0);
3884 /* This value should be large enough to cover a tagged ethernet header plus
3885 * an IPv6 header, all options, and a maximal TCP or UDP header.
3887 #define MAX_IPV6_HDR_LEN 256
3889 #define OPT_HDR(type, skb, off) \
3890 (type *)(skb_network_header(skb) + (off))
3892 static int skb_checksum_setup_ipv6(struct sk_buff
*skb
, bool recalculate
)
3905 off
= sizeof(struct ipv6hdr
);
3907 err
= skb_maybe_pull_tail(skb
, off
, MAX_IPV6_HDR_LEN
);
3911 nexthdr
= ipv6_hdr(skb
)->nexthdr
;
3913 len
= sizeof(struct ipv6hdr
) + ntohs(ipv6_hdr(skb
)->payload_len
);
3914 while (off
<= len
&& !done
) {
3916 case IPPROTO_DSTOPTS
:
3917 case IPPROTO_HOPOPTS
:
3918 case IPPROTO_ROUTING
: {
3919 struct ipv6_opt_hdr
*hp
;
3921 err
= skb_maybe_pull_tail(skb
,
3923 sizeof(struct ipv6_opt_hdr
),
3928 hp
= OPT_HDR(struct ipv6_opt_hdr
, skb
, off
);
3929 nexthdr
= hp
->nexthdr
;
3930 off
+= ipv6_optlen(hp
);
3934 struct ip_auth_hdr
*hp
;
3936 err
= skb_maybe_pull_tail(skb
,
3938 sizeof(struct ip_auth_hdr
),
3943 hp
= OPT_HDR(struct ip_auth_hdr
, skb
, off
);
3944 nexthdr
= hp
->nexthdr
;
3945 off
+= ipv6_authlen(hp
);
3948 case IPPROTO_FRAGMENT
: {
3949 struct frag_hdr
*hp
;
3951 err
= skb_maybe_pull_tail(skb
,
3953 sizeof(struct frag_hdr
),
3958 hp
= OPT_HDR(struct frag_hdr
, skb
, off
);
3960 if (hp
->frag_off
& htons(IP6_OFFSET
| IP6_MF
))
3963 nexthdr
= hp
->nexthdr
;
3964 off
+= sizeof(struct frag_hdr
);
3975 if (!done
|| fragment
)
3978 csum
= skb_checksum_setup_ip(skb
, nexthdr
, off
);
3980 return PTR_ERR(csum
);
3983 *csum
= ~csum_ipv6_magic(&ipv6_hdr(skb
)->saddr
,
3984 &ipv6_hdr(skb
)->daddr
,
3985 skb
->len
- off
, nexthdr
, 0);
3993 * skb_checksum_setup - set up partial checksum offset
3994 * @skb: the skb to set up
3995 * @recalculate: if true the pseudo-header checksum will be recalculated
3997 int skb_checksum_setup(struct sk_buff
*skb
, bool recalculate
)
4001 switch (skb
->protocol
) {
4002 case htons(ETH_P_IP
):
4003 err
= skb_checksum_setup_ipv4(skb
, recalculate
);
4006 case htons(ETH_P_IPV6
):
4007 err
= skb_checksum_setup_ipv6(skb
, recalculate
);
4017 EXPORT_SYMBOL(skb_checksum_setup
);
4020 * skb_checksum_maybe_trim - maybe trims the given skb
4021 * @skb: the skb to check
4022 * @transport_len: the data length beyond the network header
4024 * Checks whether the given skb has data beyond the given transport length.
4025 * If so, returns a cloned skb trimmed to this transport length.
4026 * Otherwise returns the provided skb. Returns NULL in error cases
4027 * (e.g. transport_len exceeds skb length or out-of-memory).
4029 * Caller needs to set the skb transport header and free any returned skb if it
4030 * differs from the provided skb.
4032 static struct sk_buff
*skb_checksum_maybe_trim(struct sk_buff
*skb
,
4033 unsigned int transport_len
)
4035 struct sk_buff
*skb_chk
;
4036 unsigned int len
= skb_transport_offset(skb
) + transport_len
;
4041 else if (skb
->len
== len
)
4044 skb_chk
= skb_clone(skb
, GFP_ATOMIC
);
4048 ret
= pskb_trim_rcsum(skb_chk
, len
);
4058 * skb_checksum_trimmed - validate checksum of an skb
4059 * @skb: the skb to check
4060 * @transport_len: the data length beyond the network header
4061 * @skb_chkf: checksum function to use
4063 * Applies the given checksum function skb_chkf to the provided skb.
4064 * Returns a checked and maybe trimmed skb. Returns NULL on error.
4066 * If the skb has data beyond the given transport length, then a
4067 * trimmed & cloned skb is checked and returned.
4069 * Caller needs to set the skb transport header and free any returned skb if it
4070 * differs from the provided skb.
4072 struct sk_buff
*skb_checksum_trimmed(struct sk_buff
*skb
,
4073 unsigned int transport_len
,
4074 __sum16(*skb_chkf
)(struct sk_buff
*skb
))
4076 struct sk_buff
*skb_chk
;
4077 unsigned int offset
= skb_transport_offset(skb
);
4080 skb_chk
= skb_checksum_maybe_trim(skb
, transport_len
);
4084 if (!pskb_may_pull(skb_chk
, offset
))
4087 __skb_pull(skb_chk
, offset
);
4088 ret
= skb_chkf(skb_chk
);
4089 __skb_push(skb_chk
, offset
);
4097 if (skb_chk
&& skb_chk
!= skb
)
4103 EXPORT_SYMBOL(skb_checksum_trimmed
);
4105 void __skb_warn_lro_forwarding(const struct sk_buff
*skb
)
4107 net_warn_ratelimited("%s: received packets cannot be forwarded while LRO is enabled\n",
4110 EXPORT_SYMBOL(__skb_warn_lro_forwarding
);
4112 void kfree_skb_partial(struct sk_buff
*skb
, bool head_stolen
)
4115 skb_release_head_state(skb
);
4116 kmem_cache_free(skbuff_head_cache
, skb
);
4121 EXPORT_SYMBOL(kfree_skb_partial
);
4124 * skb_try_coalesce - try to merge skb to prior one
4126 * @from: buffer to add
4127 * @fragstolen: pointer to boolean
4128 * @delta_truesize: how much more was allocated than was requested
4130 bool skb_try_coalesce(struct sk_buff
*to
, struct sk_buff
*from
,
4131 bool *fragstolen
, int *delta_truesize
)
4133 int i
, delta
, len
= from
->len
;
4135 *fragstolen
= false;
4140 if (len
<= skb_tailroom(to
)) {
4142 BUG_ON(skb_copy_bits(from
, 0, skb_put(to
, len
), len
));
4143 *delta_truesize
= 0;
4147 if (skb_has_frag_list(to
) || skb_has_frag_list(from
))
4150 if (skb_headlen(from
) != 0) {
4152 unsigned int offset
;
4154 if (skb_shinfo(to
)->nr_frags
+
4155 skb_shinfo(from
)->nr_frags
>= MAX_SKB_FRAGS
)
4158 if (skb_head_is_locked(from
))
4161 delta
= from
->truesize
- SKB_DATA_ALIGN(sizeof(struct sk_buff
));
4163 page
= virt_to_head_page(from
->head
);
4164 offset
= from
->data
- (unsigned char *)page_address(page
);
4166 skb_fill_page_desc(to
, skb_shinfo(to
)->nr_frags
,
4167 page
, offset
, skb_headlen(from
));
4170 if (skb_shinfo(to
)->nr_frags
+
4171 skb_shinfo(from
)->nr_frags
> MAX_SKB_FRAGS
)
4174 delta
= from
->truesize
- SKB_TRUESIZE(skb_end_offset(from
));
4177 WARN_ON_ONCE(delta
< len
);
4179 memcpy(skb_shinfo(to
)->frags
+ skb_shinfo(to
)->nr_frags
,
4180 skb_shinfo(from
)->frags
,
4181 skb_shinfo(from
)->nr_frags
* sizeof(skb_frag_t
));
4182 skb_shinfo(to
)->nr_frags
+= skb_shinfo(from
)->nr_frags
;
4184 if (!skb_cloned(from
))
4185 skb_shinfo(from
)->nr_frags
= 0;
4187 /* if the skb is not cloned this does nothing
4188 * since we set nr_frags to 0.
4190 for (i
= 0; i
< skb_shinfo(from
)->nr_frags
; i
++)
4191 skb_frag_ref(from
, i
);
4193 to
->truesize
+= delta
;
4195 to
->data_len
+= len
;
4197 *delta_truesize
= delta
;
4200 EXPORT_SYMBOL(skb_try_coalesce
);
4203 * skb_scrub_packet - scrub an skb
4205 * @skb: buffer to clean
4206 * @xnet: packet is crossing netns
4208 * skb_scrub_packet can be used after encapsulating or decapsulting a packet
4209 * into/from a tunnel. Some information have to be cleared during these
4211 * skb_scrub_packet can also be used to clean a skb before injecting it in
4212 * another namespace (@xnet == true). We have to clear all information in the
4213 * skb that could impact namespace isolation.
4215 void skb_scrub_packet(struct sk_buff
*skb
, bool xnet
)
4217 skb
->tstamp
.tv64
= 0;
4218 skb
->pkt_type
= PACKET_HOST
;
4222 skb_sender_cpu_clear(skb
);
4225 nf_reset_trace(skb
);
4233 EXPORT_SYMBOL_GPL(skb_scrub_packet
);
4236 * skb_gso_transport_seglen - Return length of individual segments of a gso packet
4240 * skb_gso_transport_seglen is used to determine the real size of the
4241 * individual segments, including Layer4 headers (TCP/UDP).
4243 * The MAC/L2 or network (IP, IPv6) headers are not accounted for.
4245 unsigned int skb_gso_transport_seglen(const struct sk_buff
*skb
)
4247 const struct skb_shared_info
*shinfo
= skb_shinfo(skb
);
4248 unsigned int thlen
= 0;
4250 if (skb
->encapsulation
) {
4251 thlen
= skb_inner_transport_header(skb
) -
4252 skb_transport_header(skb
);
4254 if (likely(shinfo
->gso_type
& (SKB_GSO_TCPV4
| SKB_GSO_TCPV6
)))
4255 thlen
+= inner_tcp_hdrlen(skb
);
4256 } else if (likely(shinfo
->gso_type
& (SKB_GSO_TCPV4
| SKB_GSO_TCPV6
))) {
4257 thlen
= tcp_hdrlen(skb
);
4259 /* UFO sets gso_size to the size of the fragmentation
4260 * payload, i.e. the size of the L4 (UDP) header is already
4263 return thlen
+ shinfo
->gso_size
;
4265 EXPORT_SYMBOL_GPL(skb_gso_transport_seglen
);
4267 static struct sk_buff
*skb_reorder_vlan_header(struct sk_buff
*skb
)
4269 if (skb_cow(skb
, skb_headroom(skb
)) < 0) {
4274 memmove(skb
->data
- ETH_HLEN
, skb
->data
- skb
->mac_len
- VLAN_HLEN
,
4276 skb
->mac_header
+= VLAN_HLEN
;
4280 struct sk_buff
*skb_vlan_untag(struct sk_buff
*skb
)
4282 struct vlan_hdr
*vhdr
;
4285 if (unlikely(skb_vlan_tag_present(skb
))) {
4286 /* vlan_tci is already set-up so leave this for another time */
4290 skb
= skb_share_check(skb
, GFP_ATOMIC
);
4294 if (unlikely(!pskb_may_pull(skb
, VLAN_HLEN
)))
4297 vhdr
= (struct vlan_hdr
*)skb
->data
;
4298 vlan_tci
= ntohs(vhdr
->h_vlan_TCI
);
4299 __vlan_hwaccel_put_tag(skb
, skb
->protocol
, vlan_tci
);
4301 skb_pull_rcsum(skb
, VLAN_HLEN
);
4302 vlan_set_encap_proto(skb
, vhdr
);
4304 skb
= skb_reorder_vlan_header(skb
);
4308 skb_reset_network_header(skb
);
4309 skb_reset_transport_header(skb
);
4310 skb_reset_mac_len(skb
);
4318 EXPORT_SYMBOL(skb_vlan_untag
);
4320 int skb_ensure_writable(struct sk_buff
*skb
, int write_len
)
4322 if (!pskb_may_pull(skb
, write_len
))
4325 if (!skb_cloned(skb
) || skb_clone_writable(skb
, write_len
))
4328 return pskb_expand_head(skb
, 0, 0, GFP_ATOMIC
);
4330 EXPORT_SYMBOL(skb_ensure_writable
);
4332 /* remove VLAN header from packet and update csum accordingly. */
4333 static int __skb_vlan_pop(struct sk_buff
*skb
, u16
*vlan_tci
)
4335 struct vlan_hdr
*vhdr
;
4336 unsigned int offset
= skb
->data
- skb_mac_header(skb
);
4339 __skb_push(skb
, offset
);
4340 err
= skb_ensure_writable(skb
, VLAN_ETH_HLEN
);
4344 skb_postpull_rcsum(skb
, skb
->data
+ (2 * ETH_ALEN
), VLAN_HLEN
);
4346 vhdr
= (struct vlan_hdr
*)(skb
->data
+ ETH_HLEN
);
4347 *vlan_tci
= ntohs(vhdr
->h_vlan_TCI
);
4349 memmove(skb
->data
+ VLAN_HLEN
, skb
->data
, 2 * ETH_ALEN
);
4350 __skb_pull(skb
, VLAN_HLEN
);
4352 vlan_set_encap_proto(skb
, vhdr
);
4353 skb
->mac_header
+= VLAN_HLEN
;
4355 if (skb_network_offset(skb
) < ETH_HLEN
)
4356 skb_set_network_header(skb
, ETH_HLEN
);
4358 skb_reset_mac_len(skb
);
4360 __skb_pull(skb
, offset
);
4365 int skb_vlan_pop(struct sk_buff
*skb
)
4371 if (likely(skb_vlan_tag_present(skb
))) {
4374 if (unlikely((skb
->protocol
!= htons(ETH_P_8021Q
) &&
4375 skb
->protocol
!= htons(ETH_P_8021AD
)) ||
4376 skb
->len
< VLAN_ETH_HLEN
))
4379 err
= __skb_vlan_pop(skb
, &vlan_tci
);
4383 /* move next vlan tag to hw accel tag */
4384 if (likely((skb
->protocol
!= htons(ETH_P_8021Q
) &&
4385 skb
->protocol
!= htons(ETH_P_8021AD
)) ||
4386 skb
->len
< VLAN_ETH_HLEN
))
4389 vlan_proto
= skb
->protocol
;
4390 err
= __skb_vlan_pop(skb
, &vlan_tci
);
4394 __vlan_hwaccel_put_tag(skb
, vlan_proto
, vlan_tci
);
4397 EXPORT_SYMBOL(skb_vlan_pop
);
4399 int skb_vlan_push(struct sk_buff
*skb
, __be16 vlan_proto
, u16 vlan_tci
)
4401 if (skb_vlan_tag_present(skb
)) {
4402 unsigned int offset
= skb
->data
- skb_mac_header(skb
);
4405 /* __vlan_insert_tag expect skb->data pointing to mac header.
4406 * So change skb->data before calling it and change back to
4407 * original position later
4409 __skb_push(skb
, offset
);
4410 err
= __vlan_insert_tag(skb
, skb
->vlan_proto
,
4411 skb_vlan_tag_get(skb
));
4414 skb
->protocol
= skb
->vlan_proto
;
4415 skb
->mac_len
+= VLAN_HLEN
;
4416 __skb_pull(skb
, offset
);
4418 if (skb
->ip_summed
== CHECKSUM_COMPLETE
)
4419 skb
->csum
= csum_add(skb
->csum
, csum_partial(skb
->data
4420 + (2 * ETH_ALEN
), VLAN_HLEN
, 0));
4422 __vlan_hwaccel_put_tag(skb
, vlan_proto
, vlan_tci
);
4425 EXPORT_SYMBOL(skb_vlan_push
);
4428 * alloc_skb_with_frags - allocate skb with page frags
4430 * @header_len: size of linear part
4431 * @data_len: needed length in frags
4432 * @max_page_order: max page order desired.
4433 * @errcode: pointer to error code if any
4434 * @gfp_mask: allocation mask
4436 * This can be used to allocate a paged skb, given a maximal order for frags.
4438 struct sk_buff
*alloc_skb_with_frags(unsigned long header_len
,
4439 unsigned long data_len
,
4444 int npages
= (data_len
+ (PAGE_SIZE
- 1)) >> PAGE_SHIFT
;
4445 unsigned long chunk
;
4446 struct sk_buff
*skb
;
4451 *errcode
= -EMSGSIZE
;
4452 /* Note this test could be relaxed, if we succeed to allocate
4453 * high order pages...
4455 if (npages
> MAX_SKB_FRAGS
)
4458 gfp_head
= gfp_mask
;
4459 if (gfp_head
& __GFP_DIRECT_RECLAIM
)
4460 gfp_head
|= __GFP_REPEAT
;
4462 *errcode
= -ENOBUFS
;
4463 skb
= alloc_skb(header_len
, gfp_head
);
4467 skb
->truesize
+= npages
<< PAGE_SHIFT
;
4469 for (i
= 0; npages
> 0; i
++) {
4470 int order
= max_page_order
;
4473 if (npages
>= 1 << order
) {
4474 page
= alloc_pages((gfp_mask
& ~__GFP_DIRECT_RECLAIM
) |
4481 /* Do not retry other high order allocations */
4487 page
= alloc_page(gfp_mask
);
4491 chunk
= min_t(unsigned long, data_len
,
4492 PAGE_SIZE
<< order
);
4493 skb_fill_page_desc(skb
, i
, page
, 0, chunk
);
4495 npages
-= 1 << order
;
4503 EXPORT_SYMBOL(alloc_skb_with_frags
);