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/netdevice.h>
51 #ifdef CONFIG_NET_CLS_ACT
52 #include <net/pkt_sched.h>
54 #include <linux/string.h>
55 #include <linux/skbuff.h>
56 #include <linux/splice.h>
57 #include <linux/cache.h>
58 #include <linux/rtnetlink.h>
59 #include <linux/init.h>
60 #include <linux/scatterlist.h>
61 #include <linux/errqueue.h>
62 #include <linux/prefetch.h>
64 #include <net/protocol.h>
67 #include <net/checksum.h>
70 #include <asm/uaccess.h>
71 #include <trace/events/skb.h>
72 #include <linux/highmem.h>
74 struct kmem_cache
*skbuff_head_cache __read_mostly
;
75 static struct kmem_cache
*skbuff_fclone_cache __read_mostly
;
77 static void sock_pipe_buf_release(struct pipe_inode_info
*pipe
,
78 struct pipe_buffer
*buf
)
83 static void sock_pipe_buf_get(struct pipe_inode_info
*pipe
,
84 struct pipe_buffer
*buf
)
89 static int sock_pipe_buf_steal(struct pipe_inode_info
*pipe
,
90 struct pipe_buffer
*buf
)
96 /* Pipe buffer operations for a socket. */
97 static const struct pipe_buf_operations sock_pipe_buf_ops
= {
99 .map
= generic_pipe_buf_map
,
100 .unmap
= generic_pipe_buf_unmap
,
101 .confirm
= generic_pipe_buf_confirm
,
102 .release
= sock_pipe_buf_release
,
103 .steal
= sock_pipe_buf_steal
,
104 .get
= sock_pipe_buf_get
,
108 * Keep out-of-line to prevent kernel bloat.
109 * __builtin_return_address is not used because it is not always
114 * skb_over_panic - private function
119 * Out of line support code for skb_put(). Not user callable.
121 static void skb_over_panic(struct sk_buff
*skb
, int sz
, void *here
)
123 pr_emerg("%s: text:%p len:%d put:%d head:%p data:%p tail:%#lx end:%#lx dev:%s\n",
124 __func__
, here
, skb
->len
, sz
, skb
->head
, skb
->data
,
125 (unsigned long)skb
->tail
, (unsigned long)skb
->end
,
126 skb
->dev
? skb
->dev
->name
: "<NULL>");
131 * skb_under_panic - private function
136 * Out of line support code for skb_push(). Not user callable.
139 static void skb_under_panic(struct sk_buff
*skb
, int sz
, void *here
)
141 pr_emerg("%s: text:%p len:%d put:%d head:%p data:%p tail:%#lx end:%#lx dev:%s\n",
142 __func__
, here
, skb
->len
, sz
, skb
->head
, skb
->data
,
143 (unsigned long)skb
->tail
, (unsigned long)skb
->end
,
144 skb
->dev
? skb
->dev
->name
: "<NULL>");
150 * kmalloc_reserve is a wrapper around kmalloc_node_track_caller that tells
151 * the caller if emergency pfmemalloc reserves are being used. If it is and
152 * the socket is later found to be SOCK_MEMALLOC then PFMEMALLOC reserves
153 * may be used. Otherwise, the packet data may be discarded until enough
156 #define kmalloc_reserve(size, gfp, node, pfmemalloc) \
157 __kmalloc_reserve(size, gfp, node, _RET_IP_, pfmemalloc)
159 static void *__kmalloc_reserve(size_t size
, gfp_t flags
, int node
,
160 unsigned long ip
, bool *pfmemalloc
)
163 bool ret_pfmemalloc
= false;
166 * Try a regular allocation, when that fails and we're not entitled
167 * to the reserves, fail.
169 obj
= kmalloc_node_track_caller(size
,
170 flags
| __GFP_NOMEMALLOC
| __GFP_NOWARN
,
172 if (obj
|| !(gfp_pfmemalloc_allowed(flags
)))
175 /* Try again but now we are using pfmemalloc reserves */
176 ret_pfmemalloc
= true;
177 obj
= kmalloc_node_track_caller(size
, flags
, node
);
181 *pfmemalloc
= ret_pfmemalloc
;
186 /* Allocate a new skbuff. We do this ourselves so we can fill in a few
187 * 'private' fields and also do memory statistics to find all the
193 * __alloc_skb - allocate a network buffer
194 * @size: size to allocate
195 * @gfp_mask: allocation mask
196 * @flags: If SKB_ALLOC_FCLONE is set, allocate from fclone cache
197 * instead of head cache and allocate a cloned (child) skb.
198 * If SKB_ALLOC_RX is set, __GFP_MEMALLOC will be used for
199 * allocations in case the data is required for writeback
200 * @node: numa node to allocate memory on
202 * Allocate a new &sk_buff. The returned buffer has no headroom and a
203 * tail room of at least size bytes. The object has a reference count
204 * of one. The return is the buffer. On a failure the return is %NULL.
206 * Buffers may only be allocated from interrupts using a @gfp_mask of
209 struct sk_buff
*__alloc_skb(unsigned int size
, gfp_t gfp_mask
,
212 struct kmem_cache
*cache
;
213 struct skb_shared_info
*shinfo
;
218 cache
= (flags
& SKB_ALLOC_FCLONE
)
219 ? skbuff_fclone_cache
: skbuff_head_cache
;
221 if (sk_memalloc_socks() && (flags
& SKB_ALLOC_RX
))
222 gfp_mask
|= __GFP_MEMALLOC
;
225 skb
= kmem_cache_alloc_node(cache
, gfp_mask
& ~__GFP_DMA
, node
);
230 /* We do our best to align skb_shared_info on a separate cache
231 * line. It usually works because kmalloc(X > SMP_CACHE_BYTES) gives
232 * aligned memory blocks, unless SLUB/SLAB debug is enabled.
233 * Both skb->head and skb_shared_info are cache line aligned.
235 size
= SKB_DATA_ALIGN(size
);
236 size
+= SKB_DATA_ALIGN(sizeof(struct skb_shared_info
));
237 data
= kmalloc_reserve(size
, gfp_mask
, node
, &pfmemalloc
);
240 /* kmalloc(size) might give us more room than requested.
241 * Put skb_shared_info exactly at the end of allocated zone,
242 * to allow max possible filling before reallocation.
244 size
= SKB_WITH_OVERHEAD(ksize(data
));
245 prefetchw(data
+ size
);
248 * Only clear those fields we need to clear, not those that we will
249 * actually initialise below. Hence, don't put any more fields after
250 * the tail pointer in struct sk_buff!
252 memset(skb
, 0, offsetof(struct sk_buff
, tail
));
253 /* Account for allocated memory : skb + skb->head */
254 skb
->truesize
= SKB_TRUESIZE(size
);
255 skb
->pfmemalloc
= pfmemalloc
;
256 atomic_set(&skb
->users
, 1);
259 skb_reset_tail_pointer(skb
);
260 skb
->end
= skb
->tail
+ size
;
261 #ifdef NET_SKBUFF_DATA_USES_OFFSET
262 skb
->mac_header
= ~0U;
263 skb
->transport_header
= ~0U;
266 /* make sure we initialize shinfo sequentially */
267 shinfo
= skb_shinfo(skb
);
268 memset(shinfo
, 0, offsetof(struct skb_shared_info
, dataref
));
269 atomic_set(&shinfo
->dataref
, 1);
270 kmemcheck_annotate_variable(shinfo
->destructor_arg
);
272 if (flags
& SKB_ALLOC_FCLONE
) {
273 struct sk_buff
*child
= skb
+ 1;
274 atomic_t
*fclone_ref
= (atomic_t
*) (child
+ 1);
276 kmemcheck_annotate_bitfield(child
, flags1
);
277 kmemcheck_annotate_bitfield(child
, flags2
);
278 skb
->fclone
= SKB_FCLONE_ORIG
;
279 atomic_set(fclone_ref
, 1);
281 child
->fclone
= SKB_FCLONE_UNAVAILABLE
;
282 child
->pfmemalloc
= pfmemalloc
;
287 kmem_cache_free(cache
, skb
);
291 EXPORT_SYMBOL(__alloc_skb
);
294 * build_skb - build a network buffer
295 * @data: data buffer provided by caller
296 * @frag_size: size of fragment, or 0 if head was kmalloced
298 * Allocate a new &sk_buff. Caller provides space holding head and
299 * skb_shared_info. @data must have been allocated by kmalloc()
300 * The return is the new skb buffer.
301 * On a failure the return is %NULL, and @data is not freed.
303 * Before IO, driver allocates only data buffer where NIC put incoming frame
304 * Driver should add room at head (NET_SKB_PAD) and
305 * MUST add room at tail (SKB_DATA_ALIGN(skb_shared_info))
306 * After IO, driver calls build_skb(), to allocate sk_buff and populate it
307 * before giving packet to stack.
308 * RX rings only contains data buffers, not full skbs.
310 struct sk_buff
*build_skb(void *data
, unsigned int frag_size
)
312 struct skb_shared_info
*shinfo
;
314 unsigned int size
= frag_size
? : ksize(data
);
316 skb
= kmem_cache_alloc(skbuff_head_cache
, GFP_ATOMIC
);
320 size
-= SKB_DATA_ALIGN(sizeof(struct skb_shared_info
));
322 memset(skb
, 0, offsetof(struct sk_buff
, tail
));
323 skb
->truesize
= SKB_TRUESIZE(size
);
324 skb
->head_frag
= frag_size
!= 0;
325 atomic_set(&skb
->users
, 1);
328 skb_reset_tail_pointer(skb
);
329 skb
->end
= skb
->tail
+ size
;
330 #ifdef NET_SKBUFF_DATA_USES_OFFSET
331 skb
->mac_header
= ~0U;
332 skb
->transport_header
= ~0U;
335 /* make sure we initialize shinfo sequentially */
336 shinfo
= skb_shinfo(skb
);
337 memset(shinfo
, 0, offsetof(struct skb_shared_info
, dataref
));
338 atomic_set(&shinfo
->dataref
, 1);
339 kmemcheck_annotate_variable(shinfo
->destructor_arg
);
343 EXPORT_SYMBOL(build_skb
);
345 struct netdev_alloc_cache
{
346 struct page_frag frag
;
347 /* we maintain a pagecount bias, so that we dont dirty cache line
348 * containing page->_count every time we allocate a fragment.
350 unsigned int pagecnt_bias
;
352 static DEFINE_PER_CPU(struct netdev_alloc_cache
, netdev_alloc_cache
);
354 #define NETDEV_FRAG_PAGE_MAX_ORDER get_order(32768)
355 #define NETDEV_FRAG_PAGE_MAX_SIZE (PAGE_SIZE << NETDEV_FRAG_PAGE_MAX_ORDER)
356 #define NETDEV_PAGECNT_MAX_BIAS NETDEV_FRAG_PAGE_MAX_SIZE
358 static void *__netdev_alloc_frag(unsigned int fragsz
, gfp_t gfp_mask
)
360 struct netdev_alloc_cache
*nc
;
365 local_irq_save(flags
);
366 nc
= &__get_cpu_var(netdev_alloc_cache
);
367 if (unlikely(!nc
->frag
.page
)) {
369 for (order
= NETDEV_FRAG_PAGE_MAX_ORDER
; ;) {
370 gfp_t gfp
= gfp_mask
;
373 gfp
|= __GFP_COMP
| __GFP_NOWARN
;
374 nc
->frag
.page
= alloc_pages(gfp
, order
);
375 if (likely(nc
->frag
.page
))
380 nc
->frag
.size
= PAGE_SIZE
<< order
;
382 atomic_set(&nc
->frag
.page
->_count
, NETDEV_PAGECNT_MAX_BIAS
);
383 nc
->pagecnt_bias
= NETDEV_PAGECNT_MAX_BIAS
;
387 if (nc
->frag
.offset
+ fragsz
> nc
->frag
.size
) {
388 /* avoid unnecessary locked operations if possible */
389 if ((atomic_read(&nc
->frag
.page
->_count
) == nc
->pagecnt_bias
) ||
390 atomic_sub_and_test(nc
->pagecnt_bias
, &nc
->frag
.page
->_count
))
395 data
= page_address(nc
->frag
.page
) + nc
->frag
.offset
;
396 nc
->frag
.offset
+= fragsz
;
399 local_irq_restore(flags
);
404 * netdev_alloc_frag - allocate a page fragment
405 * @fragsz: fragment size
407 * Allocates a frag from a page for receive buffer.
408 * Uses GFP_ATOMIC allocations.
410 void *netdev_alloc_frag(unsigned int fragsz
)
412 return __netdev_alloc_frag(fragsz
, GFP_ATOMIC
| __GFP_COLD
);
414 EXPORT_SYMBOL(netdev_alloc_frag
);
417 * __netdev_alloc_skb - allocate an skbuff for rx on a specific device
418 * @dev: network device to receive on
419 * @length: length to allocate
420 * @gfp_mask: get_free_pages mask, passed to alloc_skb
422 * Allocate a new &sk_buff and assign it a usage count of one. The
423 * buffer has unspecified headroom built in. Users should allocate
424 * the headroom they think they need without accounting for the
425 * built in space. The built in space is used for optimisations.
427 * %NULL is returned if there is no free memory.
429 struct sk_buff
*__netdev_alloc_skb(struct net_device
*dev
,
430 unsigned int length
, gfp_t gfp_mask
)
432 struct sk_buff
*skb
= NULL
;
433 unsigned int fragsz
= SKB_DATA_ALIGN(length
+ NET_SKB_PAD
) +
434 SKB_DATA_ALIGN(sizeof(struct skb_shared_info
));
436 if (fragsz
<= PAGE_SIZE
&& !(gfp_mask
& (__GFP_WAIT
| GFP_DMA
))) {
439 if (sk_memalloc_socks())
440 gfp_mask
|= __GFP_MEMALLOC
;
442 data
= __netdev_alloc_frag(fragsz
, gfp_mask
);
445 skb
= build_skb(data
, fragsz
);
447 put_page(virt_to_head_page(data
));
450 skb
= __alloc_skb(length
+ NET_SKB_PAD
, gfp_mask
,
451 SKB_ALLOC_RX
, NUMA_NO_NODE
);
454 skb_reserve(skb
, NET_SKB_PAD
);
459 EXPORT_SYMBOL(__netdev_alloc_skb
);
461 void skb_add_rx_frag(struct sk_buff
*skb
, int i
, struct page
*page
, int off
,
462 int size
, unsigned int truesize
)
464 skb_fill_page_desc(skb
, i
, page
, off
, size
);
466 skb
->data_len
+= size
;
467 skb
->truesize
+= truesize
;
469 EXPORT_SYMBOL(skb_add_rx_frag
);
471 static void skb_drop_list(struct sk_buff
**listp
)
473 struct sk_buff
*list
= *listp
;
478 struct sk_buff
*this = list
;
484 static inline void skb_drop_fraglist(struct sk_buff
*skb
)
486 skb_drop_list(&skb_shinfo(skb
)->frag_list
);
489 static void skb_clone_fraglist(struct sk_buff
*skb
)
491 struct sk_buff
*list
;
493 skb_walk_frags(skb
, list
)
497 static void skb_free_head(struct sk_buff
*skb
)
500 put_page(virt_to_head_page(skb
->head
));
505 static void skb_release_data(struct sk_buff
*skb
)
508 !atomic_sub_return(skb
->nohdr
? (1 << SKB_DATAREF_SHIFT
) + 1 : 1,
509 &skb_shinfo(skb
)->dataref
)) {
510 if (skb_shinfo(skb
)->nr_frags
) {
512 for (i
= 0; i
< skb_shinfo(skb
)->nr_frags
; i
++)
513 skb_frag_unref(skb
, i
);
517 * If skb buf is from userspace, we need to notify the caller
518 * the lower device DMA has done;
520 if (skb_shinfo(skb
)->tx_flags
& SKBTX_DEV_ZEROCOPY
) {
521 struct ubuf_info
*uarg
;
523 uarg
= skb_shinfo(skb
)->destructor_arg
;
525 uarg
->callback(uarg
, true);
528 if (skb_has_frag_list(skb
))
529 skb_drop_fraglist(skb
);
536 * Free an skbuff by memory without cleaning the state.
538 static void kfree_skbmem(struct sk_buff
*skb
)
540 struct sk_buff
*other
;
541 atomic_t
*fclone_ref
;
543 switch (skb
->fclone
) {
544 case SKB_FCLONE_UNAVAILABLE
:
545 kmem_cache_free(skbuff_head_cache
, skb
);
548 case SKB_FCLONE_ORIG
:
549 fclone_ref
= (atomic_t
*) (skb
+ 2);
550 if (atomic_dec_and_test(fclone_ref
))
551 kmem_cache_free(skbuff_fclone_cache
, skb
);
554 case SKB_FCLONE_CLONE
:
555 fclone_ref
= (atomic_t
*) (skb
+ 1);
558 /* The clone portion is available for
559 * fast-cloning again.
561 skb
->fclone
= SKB_FCLONE_UNAVAILABLE
;
563 if (atomic_dec_and_test(fclone_ref
))
564 kmem_cache_free(skbuff_fclone_cache
, other
);
569 static void skb_release_head_state(struct sk_buff
*skb
)
573 secpath_put(skb
->sp
);
575 if (skb
->destructor
) {
577 skb
->destructor(skb
);
579 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
580 nf_conntrack_put(skb
->nfct
);
582 #ifdef NET_SKBUFF_NF_DEFRAG_NEEDED
583 nf_conntrack_put_reasm(skb
->nfct_reasm
);
585 #ifdef CONFIG_BRIDGE_NETFILTER
586 nf_bridge_put(skb
->nf_bridge
);
588 /* XXX: IS this still necessary? - JHS */
589 #ifdef CONFIG_NET_SCHED
591 #ifdef CONFIG_NET_CLS_ACT
597 /* Free everything but the sk_buff shell. */
598 static void skb_release_all(struct sk_buff
*skb
)
600 skb_release_head_state(skb
);
601 skb_release_data(skb
);
605 * __kfree_skb - private function
608 * Free an sk_buff. Release anything attached to the buffer.
609 * Clean the state. This is an internal helper function. Users should
610 * always call kfree_skb
613 void __kfree_skb(struct sk_buff
*skb
)
615 skb_release_all(skb
);
618 EXPORT_SYMBOL(__kfree_skb
);
621 * kfree_skb - free an sk_buff
622 * @skb: buffer to free
624 * Drop a reference to the buffer and free it if the usage count has
627 void kfree_skb(struct sk_buff
*skb
)
631 if (likely(atomic_read(&skb
->users
) == 1))
633 else if (likely(!atomic_dec_and_test(&skb
->users
)))
635 trace_kfree_skb(skb
, __builtin_return_address(0));
638 EXPORT_SYMBOL(kfree_skb
);
641 * skb_tx_error - report an sk_buff xmit error
642 * @skb: buffer that triggered an error
644 * Report xmit error if a device callback is tracking this skb.
645 * skb must be freed afterwards.
647 void skb_tx_error(struct sk_buff
*skb
)
649 if (skb_shinfo(skb
)->tx_flags
& SKBTX_DEV_ZEROCOPY
) {
650 struct ubuf_info
*uarg
;
652 uarg
= skb_shinfo(skb
)->destructor_arg
;
654 uarg
->callback(uarg
, false);
655 skb_shinfo(skb
)->tx_flags
&= ~SKBTX_DEV_ZEROCOPY
;
658 EXPORT_SYMBOL(skb_tx_error
);
661 * consume_skb - free an skbuff
662 * @skb: buffer to free
664 * Drop a ref to the buffer and free it if the usage count has hit zero
665 * Functions identically to kfree_skb, but kfree_skb assumes that the frame
666 * is being dropped after a failure and notes that
668 void consume_skb(struct sk_buff
*skb
)
672 if (likely(atomic_read(&skb
->users
) == 1))
674 else if (likely(!atomic_dec_and_test(&skb
->users
)))
676 trace_consume_skb(skb
);
679 EXPORT_SYMBOL(consume_skb
);
681 static void __copy_skb_header(struct sk_buff
*new, const struct sk_buff
*old
)
683 new->tstamp
= old
->tstamp
;
685 new->transport_header
= old
->transport_header
;
686 new->network_header
= old
->network_header
;
687 new->mac_header
= old
->mac_header
;
688 new->inner_transport_header
= old
->inner_transport_header
;
689 new->inner_network_header
= old
->inner_transport_header
;
690 skb_dst_copy(new, old
);
691 new->rxhash
= old
->rxhash
;
692 new->ooo_okay
= old
->ooo_okay
;
693 new->l4_rxhash
= old
->l4_rxhash
;
694 new->no_fcs
= old
->no_fcs
;
695 new->encapsulation
= old
->encapsulation
;
697 new->sp
= secpath_get(old
->sp
);
699 memcpy(new->cb
, old
->cb
, sizeof(old
->cb
));
700 new->csum
= old
->csum
;
701 new->local_df
= old
->local_df
;
702 new->pkt_type
= old
->pkt_type
;
703 new->ip_summed
= old
->ip_summed
;
704 skb_copy_queue_mapping(new, old
);
705 new->priority
= old
->priority
;
706 #if IS_ENABLED(CONFIG_IP_VS)
707 new->ipvs_property
= old
->ipvs_property
;
709 new->pfmemalloc
= old
->pfmemalloc
;
710 new->protocol
= old
->protocol
;
711 new->mark
= old
->mark
;
712 new->skb_iif
= old
->skb_iif
;
714 #if IS_ENABLED(CONFIG_NETFILTER_XT_TARGET_TRACE)
715 new->nf_trace
= old
->nf_trace
;
717 #ifdef CONFIG_NET_SCHED
718 new->tc_index
= old
->tc_index
;
719 #ifdef CONFIG_NET_CLS_ACT
720 new->tc_verd
= old
->tc_verd
;
723 new->vlan_tci
= old
->vlan_tci
;
725 skb_copy_secmark(new, old
);
729 * You should not add any new code to this function. Add it to
730 * __copy_skb_header above instead.
732 static struct sk_buff
*__skb_clone(struct sk_buff
*n
, struct sk_buff
*skb
)
734 #define C(x) n->x = skb->x
736 n
->next
= n
->prev
= NULL
;
738 __copy_skb_header(n
, skb
);
743 n
->hdr_len
= skb
->nohdr
? skb_headroom(skb
) : skb
->hdr_len
;
746 n
->destructor
= NULL
;
753 atomic_set(&n
->users
, 1);
755 atomic_inc(&(skb_shinfo(skb
)->dataref
));
763 * skb_morph - morph one skb into another
764 * @dst: the skb to receive the contents
765 * @src: the skb to supply the contents
767 * This is identical to skb_clone except that the target skb is
768 * supplied by the user.
770 * The target skb is returned upon exit.
772 struct sk_buff
*skb_morph(struct sk_buff
*dst
, struct sk_buff
*src
)
774 skb_release_all(dst
);
775 return __skb_clone(dst
, src
);
777 EXPORT_SYMBOL_GPL(skb_morph
);
780 * skb_copy_ubufs - copy userspace skb frags buffers to kernel
781 * @skb: the skb to modify
782 * @gfp_mask: allocation priority
784 * This must be called on SKBTX_DEV_ZEROCOPY skb.
785 * It will copy all frags into kernel and drop the reference
786 * to userspace pages.
788 * If this function is called from an interrupt gfp_mask() must be
791 * Returns 0 on success or a negative error code on failure
792 * to allocate kernel memory to copy to.
794 int skb_copy_ubufs(struct sk_buff
*skb
, gfp_t gfp_mask
)
797 int num_frags
= skb_shinfo(skb
)->nr_frags
;
798 struct page
*page
, *head
= NULL
;
799 struct ubuf_info
*uarg
= skb_shinfo(skb
)->destructor_arg
;
801 for (i
= 0; i
< num_frags
; i
++) {
803 skb_frag_t
*f
= &skb_shinfo(skb
)->frags
[i
];
805 page
= alloc_page(gfp_mask
);
808 struct page
*next
= (struct page
*)head
->private;
814 vaddr
= kmap_atomic(skb_frag_page(f
));
815 memcpy(page_address(page
),
816 vaddr
+ f
->page_offset
, skb_frag_size(f
));
817 kunmap_atomic(vaddr
);
818 page
->private = (unsigned long)head
;
822 /* skb frags release userspace buffers */
823 for (i
= 0; i
< num_frags
; i
++)
824 skb_frag_unref(skb
, i
);
826 uarg
->callback(uarg
, false);
828 /* skb frags point to kernel buffers */
829 for (i
= num_frags
- 1; i
>= 0; i
--) {
830 __skb_fill_page_desc(skb
, i
, head
, 0,
831 skb_shinfo(skb
)->frags
[i
].size
);
832 head
= (struct page
*)head
->private;
835 skb_shinfo(skb
)->tx_flags
&= ~SKBTX_DEV_ZEROCOPY
;
838 EXPORT_SYMBOL_GPL(skb_copy_ubufs
);
841 * skb_clone - duplicate an sk_buff
842 * @skb: buffer to clone
843 * @gfp_mask: allocation priority
845 * Duplicate an &sk_buff. The new one is not owned by a socket. Both
846 * copies share the same packet data but not structure. The new
847 * buffer has a reference count of 1. If the allocation fails the
848 * function returns %NULL otherwise the new buffer is returned.
850 * If this function is called from an interrupt gfp_mask() must be
854 struct sk_buff
*skb_clone(struct sk_buff
*skb
, gfp_t gfp_mask
)
858 if (skb_orphan_frags(skb
, gfp_mask
))
862 if (skb
->fclone
== SKB_FCLONE_ORIG
&&
863 n
->fclone
== SKB_FCLONE_UNAVAILABLE
) {
864 atomic_t
*fclone_ref
= (atomic_t
*) (n
+ 1);
865 n
->fclone
= SKB_FCLONE_CLONE
;
866 atomic_inc(fclone_ref
);
868 if (skb_pfmemalloc(skb
))
869 gfp_mask
|= __GFP_MEMALLOC
;
871 n
= kmem_cache_alloc(skbuff_head_cache
, gfp_mask
);
875 kmemcheck_annotate_bitfield(n
, flags1
);
876 kmemcheck_annotate_bitfield(n
, flags2
);
877 n
->fclone
= SKB_FCLONE_UNAVAILABLE
;
880 return __skb_clone(n
, skb
);
882 EXPORT_SYMBOL(skb_clone
);
884 static void copy_skb_header(struct sk_buff
*new, const struct sk_buff
*old
)
886 #ifndef NET_SKBUFF_DATA_USES_OFFSET
888 * Shift between the two data areas in bytes
890 unsigned long offset
= new->data
- old
->data
;
893 __copy_skb_header(new, old
);
895 #ifndef NET_SKBUFF_DATA_USES_OFFSET
896 /* {transport,network,mac}_header are relative to skb->head */
897 new->transport_header
+= offset
;
898 new->network_header
+= offset
;
899 if (skb_mac_header_was_set(new))
900 new->mac_header
+= offset
;
901 new->inner_transport_header
+= offset
;
902 new->inner_network_header
+= offset
;
904 skb_shinfo(new)->gso_size
= skb_shinfo(old
)->gso_size
;
905 skb_shinfo(new)->gso_segs
= skb_shinfo(old
)->gso_segs
;
906 skb_shinfo(new)->gso_type
= skb_shinfo(old
)->gso_type
;
909 static inline int skb_alloc_rx_flag(const struct sk_buff
*skb
)
911 if (skb_pfmemalloc(skb
))
917 * skb_copy - create private copy of an sk_buff
918 * @skb: buffer to copy
919 * @gfp_mask: allocation priority
921 * Make a copy of both an &sk_buff and its data. This is used when the
922 * caller wishes to modify the data and needs a private copy of the
923 * data to alter. Returns %NULL on failure or the pointer to the buffer
924 * on success. The returned buffer has a reference count of 1.
926 * As by-product this function converts non-linear &sk_buff to linear
927 * one, so that &sk_buff becomes completely private and caller is allowed
928 * to modify all the data of returned buffer. This means that this
929 * function is not recommended for use in circumstances when only
930 * header is going to be modified. Use pskb_copy() instead.
933 struct sk_buff
*skb_copy(const struct sk_buff
*skb
, gfp_t gfp_mask
)
935 int headerlen
= skb_headroom(skb
);
936 unsigned int size
= skb_end_offset(skb
) + skb
->data_len
;
937 struct sk_buff
*n
= __alloc_skb(size
, gfp_mask
,
938 skb_alloc_rx_flag(skb
), NUMA_NO_NODE
);
943 /* Set the data pointer */
944 skb_reserve(n
, headerlen
);
945 /* Set the tail pointer and length */
946 skb_put(n
, skb
->len
);
948 if (skb_copy_bits(skb
, -headerlen
, n
->head
, headerlen
+ skb
->len
))
951 copy_skb_header(n
, skb
);
954 EXPORT_SYMBOL(skb_copy
);
957 * __pskb_copy - create copy of an sk_buff with private head.
958 * @skb: buffer to copy
959 * @headroom: headroom of new skb
960 * @gfp_mask: allocation priority
962 * Make a copy of both an &sk_buff and part of its data, located
963 * in header. Fragmented data remain shared. This is used when
964 * the caller wishes to modify only header of &sk_buff and needs
965 * private copy of the header to alter. Returns %NULL on failure
966 * or the pointer to the buffer on success.
967 * The returned buffer has a reference count of 1.
970 struct sk_buff
*__pskb_copy(struct sk_buff
*skb
, int headroom
, gfp_t gfp_mask
)
972 unsigned int size
= skb_headlen(skb
) + headroom
;
973 struct sk_buff
*n
= __alloc_skb(size
, gfp_mask
,
974 skb_alloc_rx_flag(skb
), NUMA_NO_NODE
);
979 /* Set the data pointer */
980 skb_reserve(n
, headroom
);
981 /* Set the tail pointer and length */
982 skb_put(n
, skb_headlen(skb
));
984 skb_copy_from_linear_data(skb
, n
->data
, n
->len
);
986 n
->truesize
+= skb
->data_len
;
987 n
->data_len
= skb
->data_len
;
990 if (skb_shinfo(skb
)->nr_frags
) {
993 if (skb_orphan_frags(skb
, gfp_mask
)) {
998 for (i
= 0; i
< skb_shinfo(skb
)->nr_frags
; i
++) {
999 skb_shinfo(n
)->frags
[i
] = skb_shinfo(skb
)->frags
[i
];
1000 skb_frag_ref(skb
, i
);
1002 skb_shinfo(n
)->nr_frags
= i
;
1005 if (skb_has_frag_list(skb
)) {
1006 skb_shinfo(n
)->frag_list
= skb_shinfo(skb
)->frag_list
;
1007 skb_clone_fraglist(n
);
1010 copy_skb_header(n
, skb
);
1014 EXPORT_SYMBOL(__pskb_copy
);
1017 * pskb_expand_head - reallocate header of &sk_buff
1018 * @skb: buffer to reallocate
1019 * @nhead: room to add at head
1020 * @ntail: room to add at tail
1021 * @gfp_mask: allocation priority
1023 * Expands (or creates identical copy, if &nhead and &ntail are zero)
1024 * header of skb. &sk_buff itself is not changed. &sk_buff MUST have
1025 * reference count of 1. Returns zero in the case of success or error,
1026 * if expansion failed. In the last case, &sk_buff is not changed.
1028 * All the pointers pointing into skb header may change and must be
1029 * reloaded after call to this function.
1032 int pskb_expand_head(struct sk_buff
*skb
, int nhead
, int ntail
,
1037 int size
= nhead
+ skb_end_offset(skb
) + ntail
;
1042 if (skb_shared(skb
))
1045 size
= SKB_DATA_ALIGN(size
);
1047 if (skb_pfmemalloc(skb
))
1048 gfp_mask
|= __GFP_MEMALLOC
;
1049 data
= kmalloc_reserve(size
+ SKB_DATA_ALIGN(sizeof(struct skb_shared_info
)),
1050 gfp_mask
, NUMA_NO_NODE
, NULL
);
1053 size
= SKB_WITH_OVERHEAD(ksize(data
));
1055 /* Copy only real data... and, alas, header. This should be
1056 * optimized for the cases when header is void.
1058 memcpy(data
+ nhead
, skb
->head
, skb_tail_pointer(skb
) - skb
->head
);
1060 memcpy((struct skb_shared_info
*)(data
+ size
),
1062 offsetof(struct skb_shared_info
, frags
[skb_shinfo(skb
)->nr_frags
]));
1065 * if shinfo is shared we must drop the old head gracefully, but if it
1066 * is not we can just drop the old head and let the existing refcount
1067 * be since all we did is relocate the values
1069 if (skb_cloned(skb
)) {
1070 /* copy this zero copy skb frags */
1071 if (skb_orphan_frags(skb
, gfp_mask
))
1073 for (i
= 0; i
< skb_shinfo(skb
)->nr_frags
; i
++)
1074 skb_frag_ref(skb
, i
);
1076 if (skb_has_frag_list(skb
))
1077 skb_clone_fraglist(skb
);
1079 skb_release_data(skb
);
1083 off
= (data
+ nhead
) - skb
->head
;
1088 #ifdef NET_SKBUFF_DATA_USES_OFFSET
1092 skb
->end
= skb
->head
+ size
;
1094 /* {transport,network,mac}_header and tail are relative to skb->head */
1096 skb
->transport_header
+= off
;
1097 skb
->network_header
+= off
;
1098 if (skb_mac_header_was_set(skb
))
1099 skb
->mac_header
+= off
;
1100 skb
->inner_transport_header
+= off
;
1101 skb
->inner_network_header
+= off
;
1102 /* Only adjust this if it actually is csum_start rather than csum */
1103 if (skb
->ip_summed
== CHECKSUM_PARTIAL
)
1104 skb
->csum_start
+= nhead
;
1108 atomic_set(&skb_shinfo(skb
)->dataref
, 1);
1116 EXPORT_SYMBOL(pskb_expand_head
);
1118 /* Make private copy of skb with writable head and some headroom */
1120 struct sk_buff
*skb_realloc_headroom(struct sk_buff
*skb
, unsigned int headroom
)
1122 struct sk_buff
*skb2
;
1123 int delta
= headroom
- skb_headroom(skb
);
1126 skb2
= pskb_copy(skb
, GFP_ATOMIC
);
1128 skb2
= skb_clone(skb
, GFP_ATOMIC
);
1129 if (skb2
&& pskb_expand_head(skb2
, SKB_DATA_ALIGN(delta
), 0,
1137 EXPORT_SYMBOL(skb_realloc_headroom
);
1140 * skb_copy_expand - copy and expand sk_buff
1141 * @skb: buffer to copy
1142 * @newheadroom: new free bytes at head
1143 * @newtailroom: new free bytes at tail
1144 * @gfp_mask: allocation priority
1146 * Make a copy of both an &sk_buff and its data and while doing so
1147 * allocate additional space.
1149 * This is used when the caller wishes to modify the data and needs a
1150 * private copy of the data to alter as well as more space for new fields.
1151 * Returns %NULL on failure or the pointer to the buffer
1152 * on success. The returned buffer has a reference count of 1.
1154 * You must pass %GFP_ATOMIC as the allocation priority if this function
1155 * is called from an interrupt.
1157 struct sk_buff
*skb_copy_expand(const struct sk_buff
*skb
,
1158 int newheadroom
, int newtailroom
,
1162 * Allocate the copy buffer
1164 struct sk_buff
*n
= __alloc_skb(newheadroom
+ skb
->len
+ newtailroom
,
1165 gfp_mask
, skb_alloc_rx_flag(skb
),
1167 int oldheadroom
= skb_headroom(skb
);
1168 int head_copy_len
, head_copy_off
;
1174 skb_reserve(n
, newheadroom
);
1176 /* Set the tail pointer and length */
1177 skb_put(n
, skb
->len
);
1179 head_copy_len
= oldheadroom
;
1181 if (newheadroom
<= head_copy_len
)
1182 head_copy_len
= newheadroom
;
1184 head_copy_off
= newheadroom
- head_copy_len
;
1186 /* Copy the linear header and data. */
1187 if (skb_copy_bits(skb
, -head_copy_len
, n
->head
+ head_copy_off
,
1188 skb
->len
+ head_copy_len
))
1191 copy_skb_header(n
, skb
);
1193 off
= newheadroom
- oldheadroom
;
1194 if (n
->ip_summed
== CHECKSUM_PARTIAL
)
1195 n
->csum_start
+= off
;
1196 #ifdef NET_SKBUFF_DATA_USES_OFFSET
1197 n
->transport_header
+= off
;
1198 n
->network_header
+= off
;
1199 if (skb_mac_header_was_set(skb
))
1200 n
->mac_header
+= off
;
1201 n
->inner_transport_header
+= off
;
1202 n
->inner_network_header
+= off
;
1207 EXPORT_SYMBOL(skb_copy_expand
);
1210 * skb_pad - zero pad the tail of an skb
1211 * @skb: buffer to pad
1212 * @pad: space to pad
1214 * Ensure that a buffer is followed by a padding area that is zero
1215 * filled. Used by network drivers which may DMA or transfer data
1216 * beyond the buffer end onto the wire.
1218 * May return error in out of memory cases. The skb is freed on error.
1221 int skb_pad(struct sk_buff
*skb
, int pad
)
1226 /* If the skbuff is non linear tailroom is always zero.. */
1227 if (!skb_cloned(skb
) && skb_tailroom(skb
) >= pad
) {
1228 memset(skb
->data
+skb
->len
, 0, pad
);
1232 ntail
= skb
->data_len
+ pad
- (skb
->end
- skb
->tail
);
1233 if (likely(skb_cloned(skb
) || ntail
> 0)) {
1234 err
= pskb_expand_head(skb
, 0, ntail
, GFP_ATOMIC
);
1239 /* FIXME: The use of this function with non-linear skb's really needs
1242 err
= skb_linearize(skb
);
1246 memset(skb
->data
+ skb
->len
, 0, pad
);
1253 EXPORT_SYMBOL(skb_pad
);
1256 * skb_put - add data to a buffer
1257 * @skb: buffer to use
1258 * @len: amount of data to add
1260 * This function extends the used data area of the buffer. If this would
1261 * exceed the total buffer size the kernel will panic. A pointer to the
1262 * first byte of the extra data is returned.
1264 unsigned char *skb_put(struct sk_buff
*skb
, unsigned int len
)
1266 unsigned char *tmp
= skb_tail_pointer(skb
);
1267 SKB_LINEAR_ASSERT(skb
);
1270 if (unlikely(skb
->tail
> skb
->end
))
1271 skb_over_panic(skb
, len
, __builtin_return_address(0));
1274 EXPORT_SYMBOL(skb_put
);
1277 * skb_push - add data to the start of a buffer
1278 * @skb: buffer to use
1279 * @len: amount of data to add
1281 * This function extends the used data area of the buffer at the buffer
1282 * start. If this would exceed the total buffer headroom the kernel will
1283 * panic. A pointer to the first byte of the extra data is returned.
1285 unsigned char *skb_push(struct sk_buff
*skb
, unsigned int len
)
1289 if (unlikely(skb
->data
<skb
->head
))
1290 skb_under_panic(skb
, len
, __builtin_return_address(0));
1293 EXPORT_SYMBOL(skb_push
);
1296 * skb_pull - remove data from the start of a buffer
1297 * @skb: buffer to use
1298 * @len: amount of data to remove
1300 * This function removes data from the start of a buffer, returning
1301 * the memory to the headroom. A pointer to the next data in the buffer
1302 * is returned. Once the data has been pulled future pushes will overwrite
1305 unsigned char *skb_pull(struct sk_buff
*skb
, unsigned int len
)
1307 return skb_pull_inline(skb
, len
);
1309 EXPORT_SYMBOL(skb_pull
);
1312 * skb_trim - remove end from a buffer
1313 * @skb: buffer to alter
1316 * Cut the length of a buffer down by removing data from the tail. If
1317 * the buffer is already under the length specified it is not modified.
1318 * The skb must be linear.
1320 void skb_trim(struct sk_buff
*skb
, unsigned int len
)
1323 __skb_trim(skb
, len
);
1325 EXPORT_SYMBOL(skb_trim
);
1327 /* Trims skb to length len. It can change skb pointers.
1330 int ___pskb_trim(struct sk_buff
*skb
, unsigned int len
)
1332 struct sk_buff
**fragp
;
1333 struct sk_buff
*frag
;
1334 int offset
= skb_headlen(skb
);
1335 int nfrags
= skb_shinfo(skb
)->nr_frags
;
1339 if (skb_cloned(skb
) &&
1340 unlikely((err
= pskb_expand_head(skb
, 0, 0, GFP_ATOMIC
))))
1347 for (; i
< nfrags
; i
++) {
1348 int end
= offset
+ skb_frag_size(&skb_shinfo(skb
)->frags
[i
]);
1355 skb_frag_size_set(&skb_shinfo(skb
)->frags
[i
++], len
- offset
);
1358 skb_shinfo(skb
)->nr_frags
= i
;
1360 for (; i
< nfrags
; i
++)
1361 skb_frag_unref(skb
, i
);
1363 if (skb_has_frag_list(skb
))
1364 skb_drop_fraglist(skb
);
1368 for (fragp
= &skb_shinfo(skb
)->frag_list
; (frag
= *fragp
);
1369 fragp
= &frag
->next
) {
1370 int end
= offset
+ frag
->len
;
1372 if (skb_shared(frag
)) {
1373 struct sk_buff
*nfrag
;
1375 nfrag
= skb_clone(frag
, GFP_ATOMIC
);
1376 if (unlikely(!nfrag
))
1379 nfrag
->next
= frag
->next
;
1391 unlikely((err
= pskb_trim(frag
, len
- offset
))))
1395 skb_drop_list(&frag
->next
);
1400 if (len
> skb_headlen(skb
)) {
1401 skb
->data_len
-= skb
->len
- len
;
1406 skb_set_tail_pointer(skb
, len
);
1411 EXPORT_SYMBOL(___pskb_trim
);
1414 * __pskb_pull_tail - advance tail of skb header
1415 * @skb: buffer to reallocate
1416 * @delta: number of bytes to advance tail
1418 * The function makes a sense only on a fragmented &sk_buff,
1419 * it expands header moving its tail forward and copying necessary
1420 * data from fragmented part.
1422 * &sk_buff MUST have reference count of 1.
1424 * Returns %NULL (and &sk_buff does not change) if pull failed
1425 * or value of new tail of skb in the case of success.
1427 * All the pointers pointing into skb header may change and must be
1428 * reloaded after call to this function.
1431 /* Moves tail of skb head forward, copying data from fragmented part,
1432 * when it is necessary.
1433 * 1. It may fail due to malloc failure.
1434 * 2. It may change skb pointers.
1436 * It is pretty complicated. Luckily, it is called only in exceptional cases.
1438 unsigned char *__pskb_pull_tail(struct sk_buff
*skb
, int delta
)
1440 /* If skb has not enough free space at tail, get new one
1441 * plus 128 bytes for future expansions. If we have enough
1442 * room at tail, reallocate without expansion only if skb is cloned.
1444 int i
, k
, eat
= (skb
->tail
+ delta
) - skb
->end
;
1446 if (eat
> 0 || skb_cloned(skb
)) {
1447 if (pskb_expand_head(skb
, 0, eat
> 0 ? eat
+ 128 : 0,
1452 if (skb_copy_bits(skb
, skb_headlen(skb
), skb_tail_pointer(skb
), delta
))
1455 /* Optimization: no fragments, no reasons to preestimate
1456 * size of pulled pages. Superb.
1458 if (!skb_has_frag_list(skb
))
1461 /* Estimate size of pulled pages. */
1463 for (i
= 0; i
< skb_shinfo(skb
)->nr_frags
; i
++) {
1464 int size
= skb_frag_size(&skb_shinfo(skb
)->frags
[i
]);
1471 /* If we need update frag list, we are in troubles.
1472 * Certainly, it possible to add an offset to skb data,
1473 * but taking into account that pulling is expected to
1474 * be very rare operation, it is worth to fight against
1475 * further bloating skb head and crucify ourselves here instead.
1476 * Pure masohism, indeed. 8)8)
1479 struct sk_buff
*list
= skb_shinfo(skb
)->frag_list
;
1480 struct sk_buff
*clone
= NULL
;
1481 struct sk_buff
*insp
= NULL
;
1486 if (list
->len
<= eat
) {
1487 /* Eaten as whole. */
1492 /* Eaten partially. */
1494 if (skb_shared(list
)) {
1495 /* Sucks! We need to fork list. :-( */
1496 clone
= skb_clone(list
, GFP_ATOMIC
);
1502 /* This may be pulled without
1506 if (!pskb_pull(list
, eat
)) {
1514 /* Free pulled out fragments. */
1515 while ((list
= skb_shinfo(skb
)->frag_list
) != insp
) {
1516 skb_shinfo(skb
)->frag_list
= list
->next
;
1519 /* And insert new clone at head. */
1522 skb_shinfo(skb
)->frag_list
= clone
;
1525 /* Success! Now we may commit changes to skb data. */
1530 for (i
= 0; i
< skb_shinfo(skb
)->nr_frags
; i
++) {
1531 int size
= skb_frag_size(&skb_shinfo(skb
)->frags
[i
]);
1534 skb_frag_unref(skb
, i
);
1537 skb_shinfo(skb
)->frags
[k
] = skb_shinfo(skb
)->frags
[i
];
1539 skb_shinfo(skb
)->frags
[k
].page_offset
+= eat
;
1540 skb_frag_size_sub(&skb_shinfo(skb
)->frags
[k
], eat
);
1546 skb_shinfo(skb
)->nr_frags
= k
;
1549 skb
->data_len
-= delta
;
1551 return skb_tail_pointer(skb
);
1553 EXPORT_SYMBOL(__pskb_pull_tail
);
1556 * skb_copy_bits - copy bits from skb to kernel buffer
1558 * @offset: offset in source
1559 * @to: destination buffer
1560 * @len: number of bytes to copy
1562 * Copy the specified number of bytes from the source skb to the
1563 * destination buffer.
1566 * If its prototype is ever changed,
1567 * check arch/{*}/net/{*}.S files,
1568 * since it is called from BPF assembly code.
1570 int skb_copy_bits(const struct sk_buff
*skb
, int offset
, void *to
, int len
)
1572 int start
= skb_headlen(skb
);
1573 struct sk_buff
*frag_iter
;
1576 if (offset
> (int)skb
->len
- len
)
1580 if ((copy
= start
- offset
) > 0) {
1583 skb_copy_from_linear_data_offset(skb
, offset
, to
, copy
);
1584 if ((len
-= copy
) == 0)
1590 for (i
= 0; i
< skb_shinfo(skb
)->nr_frags
; i
++) {
1592 skb_frag_t
*f
= &skb_shinfo(skb
)->frags
[i
];
1594 WARN_ON(start
> offset
+ len
);
1596 end
= start
+ skb_frag_size(f
);
1597 if ((copy
= end
- offset
) > 0) {
1603 vaddr
= kmap_atomic(skb_frag_page(f
));
1605 vaddr
+ f
->page_offset
+ offset
- start
,
1607 kunmap_atomic(vaddr
);
1609 if ((len
-= copy
) == 0)
1617 skb_walk_frags(skb
, frag_iter
) {
1620 WARN_ON(start
> offset
+ len
);
1622 end
= start
+ frag_iter
->len
;
1623 if ((copy
= end
- offset
) > 0) {
1626 if (skb_copy_bits(frag_iter
, offset
- start
, to
, copy
))
1628 if ((len
-= copy
) == 0)
1642 EXPORT_SYMBOL(skb_copy_bits
);
1645 * Callback from splice_to_pipe(), if we need to release some pages
1646 * at the end of the spd in case we error'ed out in filling the pipe.
1648 static void sock_spd_release(struct splice_pipe_desc
*spd
, unsigned int i
)
1650 put_page(spd
->pages
[i
]);
1653 static struct page
*linear_to_page(struct page
*page
, unsigned int *len
,
1654 unsigned int *offset
,
1657 struct page_frag
*pfrag
= sk_page_frag(sk
);
1659 if (!sk_page_frag_refill(sk
, pfrag
))
1662 *len
= min_t(unsigned int, *len
, pfrag
->size
- pfrag
->offset
);
1664 memcpy(page_address(pfrag
->page
) + pfrag
->offset
,
1665 page_address(page
) + *offset
, *len
);
1666 *offset
= pfrag
->offset
;
1667 pfrag
->offset
+= *len
;
1672 static bool spd_can_coalesce(const struct splice_pipe_desc
*spd
,
1674 unsigned int offset
)
1676 return spd
->nr_pages
&&
1677 spd
->pages
[spd
->nr_pages
- 1] == page
&&
1678 (spd
->partial
[spd
->nr_pages
- 1].offset
+
1679 spd
->partial
[spd
->nr_pages
- 1].len
== offset
);
1683 * Fill page/offset/length into spd, if it can hold more pages.
1685 static bool spd_fill_page(struct splice_pipe_desc
*spd
,
1686 struct pipe_inode_info
*pipe
, struct page
*page
,
1687 unsigned int *len
, unsigned int offset
,
1691 if (unlikely(spd
->nr_pages
== MAX_SKB_FRAGS
))
1695 page
= linear_to_page(page
, len
, &offset
, sk
);
1699 if (spd_can_coalesce(spd
, page
, offset
)) {
1700 spd
->partial
[spd
->nr_pages
- 1].len
+= *len
;
1704 spd
->pages
[spd
->nr_pages
] = page
;
1705 spd
->partial
[spd
->nr_pages
].len
= *len
;
1706 spd
->partial
[spd
->nr_pages
].offset
= offset
;
1712 static bool __splice_segment(struct page
*page
, unsigned int poff
,
1713 unsigned int plen
, unsigned int *off
,
1715 struct splice_pipe_desc
*spd
, bool linear
,
1717 struct pipe_inode_info
*pipe
)
1722 /* skip this segment if already processed */
1728 /* ignore any bits we already processed */
1734 unsigned int flen
= min(*len
, plen
);
1736 if (spd_fill_page(spd
, pipe
, page
, &flen
, poff
,
1742 } while (*len
&& plen
);
1748 * Map linear and fragment data from the skb to spd. It reports true if the
1749 * pipe is full or if we already spliced the requested length.
1751 static bool __skb_splice_bits(struct sk_buff
*skb
, struct pipe_inode_info
*pipe
,
1752 unsigned int *offset
, unsigned int *len
,
1753 struct splice_pipe_desc
*spd
, struct sock
*sk
)
1757 /* map the linear part :
1758 * If skb->head_frag is set, this 'linear' part is backed by a
1759 * fragment, and if the head is not shared with any clones then
1760 * we can avoid a copy since we own the head portion of this page.
1762 if (__splice_segment(virt_to_page(skb
->data
),
1763 (unsigned long) skb
->data
& (PAGE_SIZE
- 1),
1766 skb_head_is_locked(skb
),
1771 * then map the fragments
1773 for (seg
= 0; seg
< skb_shinfo(skb
)->nr_frags
; seg
++) {
1774 const skb_frag_t
*f
= &skb_shinfo(skb
)->frags
[seg
];
1776 if (__splice_segment(skb_frag_page(f
),
1777 f
->page_offset
, skb_frag_size(f
),
1778 offset
, len
, spd
, false, sk
, pipe
))
1786 * Map data from the skb to a pipe. Should handle both the linear part,
1787 * the fragments, and the frag list. It does NOT handle frag lists within
1788 * the frag list, if such a thing exists. We'd probably need to recurse to
1789 * handle that cleanly.
1791 int skb_splice_bits(struct sk_buff
*skb
, unsigned int offset
,
1792 struct pipe_inode_info
*pipe
, unsigned int tlen
,
1795 struct partial_page partial
[MAX_SKB_FRAGS
];
1796 struct page
*pages
[MAX_SKB_FRAGS
];
1797 struct splice_pipe_desc spd
= {
1800 .nr_pages_max
= MAX_SKB_FRAGS
,
1802 .ops
= &sock_pipe_buf_ops
,
1803 .spd_release
= sock_spd_release
,
1805 struct sk_buff
*frag_iter
;
1806 struct sock
*sk
= skb
->sk
;
1810 * __skb_splice_bits() only fails if the output has no room left,
1811 * so no point in going over the frag_list for the error case.
1813 if (__skb_splice_bits(skb
, pipe
, &offset
, &tlen
, &spd
, sk
))
1819 * now see if we have a frag_list to map
1821 skb_walk_frags(skb
, frag_iter
) {
1824 if (__skb_splice_bits(frag_iter
, pipe
, &offset
, &tlen
, &spd
, sk
))
1831 * Drop the socket lock, otherwise we have reverse
1832 * locking dependencies between sk_lock and i_mutex
1833 * here as compared to sendfile(). We enter here
1834 * with the socket lock held, and splice_to_pipe() will
1835 * grab the pipe inode lock. For sendfile() emulation,
1836 * we call into ->sendpage() with the i_mutex lock held
1837 * and networking will grab the socket lock.
1840 ret
= splice_to_pipe(pipe
, &spd
);
1848 * skb_store_bits - store bits from kernel buffer to skb
1849 * @skb: destination buffer
1850 * @offset: offset in destination
1851 * @from: source buffer
1852 * @len: number of bytes to copy
1854 * Copy the specified number of bytes from the source buffer to the
1855 * destination skb. This function handles all the messy bits of
1856 * traversing fragment lists and such.
1859 int skb_store_bits(struct sk_buff
*skb
, int offset
, const void *from
, int len
)
1861 int start
= skb_headlen(skb
);
1862 struct sk_buff
*frag_iter
;
1865 if (offset
> (int)skb
->len
- len
)
1868 if ((copy
= start
- offset
) > 0) {
1871 skb_copy_to_linear_data_offset(skb
, offset
, from
, copy
);
1872 if ((len
-= copy
) == 0)
1878 for (i
= 0; i
< skb_shinfo(skb
)->nr_frags
; i
++) {
1879 skb_frag_t
*frag
= &skb_shinfo(skb
)->frags
[i
];
1882 WARN_ON(start
> offset
+ len
);
1884 end
= start
+ skb_frag_size(frag
);
1885 if ((copy
= end
- offset
) > 0) {
1891 vaddr
= kmap_atomic(skb_frag_page(frag
));
1892 memcpy(vaddr
+ frag
->page_offset
+ offset
- start
,
1894 kunmap_atomic(vaddr
);
1896 if ((len
-= copy
) == 0)
1904 skb_walk_frags(skb
, frag_iter
) {
1907 WARN_ON(start
> offset
+ len
);
1909 end
= start
+ frag_iter
->len
;
1910 if ((copy
= end
- offset
) > 0) {
1913 if (skb_store_bits(frag_iter
, offset
- start
,
1916 if ((len
-= copy
) == 0)
1929 EXPORT_SYMBOL(skb_store_bits
);
1931 /* Checksum skb data. */
1933 __wsum
skb_checksum(const struct sk_buff
*skb
, int offset
,
1934 int len
, __wsum csum
)
1936 int start
= skb_headlen(skb
);
1937 int i
, copy
= start
- offset
;
1938 struct sk_buff
*frag_iter
;
1941 /* Checksum header. */
1945 csum
= csum_partial(skb
->data
+ offset
, copy
, csum
);
1946 if ((len
-= copy
) == 0)
1952 for (i
= 0; i
< skb_shinfo(skb
)->nr_frags
; i
++) {
1954 skb_frag_t
*frag
= &skb_shinfo(skb
)->frags
[i
];
1956 WARN_ON(start
> offset
+ len
);
1958 end
= start
+ skb_frag_size(frag
);
1959 if ((copy
= end
- offset
) > 0) {
1965 vaddr
= kmap_atomic(skb_frag_page(frag
));
1966 csum2
= csum_partial(vaddr
+ frag
->page_offset
+
1967 offset
- start
, copy
, 0);
1968 kunmap_atomic(vaddr
);
1969 csum
= csum_block_add(csum
, csum2
, pos
);
1978 skb_walk_frags(skb
, frag_iter
) {
1981 WARN_ON(start
> offset
+ len
);
1983 end
= start
+ frag_iter
->len
;
1984 if ((copy
= end
- offset
) > 0) {
1988 csum2
= skb_checksum(frag_iter
, offset
- start
,
1990 csum
= csum_block_add(csum
, csum2
, pos
);
1991 if ((len
-= copy
) == 0)
2002 EXPORT_SYMBOL(skb_checksum
);
2004 /* Both of above in one bottle. */
2006 __wsum
skb_copy_and_csum_bits(const struct sk_buff
*skb
, int offset
,
2007 u8
*to
, int len
, __wsum csum
)
2009 int start
= skb_headlen(skb
);
2010 int i
, copy
= start
- offset
;
2011 struct sk_buff
*frag_iter
;
2018 csum
= csum_partial_copy_nocheck(skb
->data
+ offset
, to
,
2020 if ((len
-= copy
) == 0)
2027 for (i
= 0; i
< skb_shinfo(skb
)->nr_frags
; i
++) {
2030 WARN_ON(start
> offset
+ len
);
2032 end
= start
+ skb_frag_size(&skb_shinfo(skb
)->frags
[i
]);
2033 if ((copy
= end
- offset
) > 0) {
2036 skb_frag_t
*frag
= &skb_shinfo(skb
)->frags
[i
];
2040 vaddr
= kmap_atomic(skb_frag_page(frag
));
2041 csum2
= csum_partial_copy_nocheck(vaddr
+
2045 kunmap_atomic(vaddr
);
2046 csum
= csum_block_add(csum
, csum2
, pos
);
2056 skb_walk_frags(skb
, frag_iter
) {
2060 WARN_ON(start
> offset
+ len
);
2062 end
= start
+ frag_iter
->len
;
2063 if ((copy
= end
- offset
) > 0) {
2066 csum2
= skb_copy_and_csum_bits(frag_iter
,
2069 csum
= csum_block_add(csum
, csum2
, pos
);
2070 if ((len
-= copy
) == 0)
2081 EXPORT_SYMBOL(skb_copy_and_csum_bits
);
2083 void skb_copy_and_csum_dev(const struct sk_buff
*skb
, u8
*to
)
2088 if (skb
->ip_summed
== CHECKSUM_PARTIAL
)
2089 csstart
= skb_checksum_start_offset(skb
);
2091 csstart
= skb_headlen(skb
);
2093 BUG_ON(csstart
> skb_headlen(skb
));
2095 skb_copy_from_linear_data(skb
, to
, csstart
);
2098 if (csstart
!= skb
->len
)
2099 csum
= skb_copy_and_csum_bits(skb
, csstart
, to
+ csstart
,
2100 skb
->len
- csstart
, 0);
2102 if (skb
->ip_summed
== CHECKSUM_PARTIAL
) {
2103 long csstuff
= csstart
+ skb
->csum_offset
;
2105 *((__sum16
*)(to
+ csstuff
)) = csum_fold(csum
);
2108 EXPORT_SYMBOL(skb_copy_and_csum_dev
);
2111 * skb_dequeue - remove from the head of the queue
2112 * @list: list to dequeue from
2114 * Remove the head of the list. The list lock is taken so the function
2115 * may be used safely with other locking list functions. The head item is
2116 * returned or %NULL if the list is empty.
2119 struct sk_buff
*skb_dequeue(struct sk_buff_head
*list
)
2121 unsigned long flags
;
2122 struct sk_buff
*result
;
2124 spin_lock_irqsave(&list
->lock
, flags
);
2125 result
= __skb_dequeue(list
);
2126 spin_unlock_irqrestore(&list
->lock
, flags
);
2129 EXPORT_SYMBOL(skb_dequeue
);
2132 * skb_dequeue_tail - remove from the tail of the queue
2133 * @list: list to dequeue from
2135 * Remove the tail of the list. The list lock is taken so the function
2136 * may be used safely with other locking list functions. The tail item is
2137 * returned or %NULL if the list is empty.
2139 struct sk_buff
*skb_dequeue_tail(struct sk_buff_head
*list
)
2141 unsigned long flags
;
2142 struct sk_buff
*result
;
2144 spin_lock_irqsave(&list
->lock
, flags
);
2145 result
= __skb_dequeue_tail(list
);
2146 spin_unlock_irqrestore(&list
->lock
, flags
);
2149 EXPORT_SYMBOL(skb_dequeue_tail
);
2152 * skb_queue_purge - empty a list
2153 * @list: list to empty
2155 * Delete all buffers on an &sk_buff list. Each buffer is removed from
2156 * the list and one reference dropped. This function takes the list
2157 * lock and is atomic with respect to other list locking functions.
2159 void skb_queue_purge(struct sk_buff_head
*list
)
2161 struct sk_buff
*skb
;
2162 while ((skb
= skb_dequeue(list
)) != NULL
)
2165 EXPORT_SYMBOL(skb_queue_purge
);
2168 * skb_queue_head - queue a buffer at the list head
2169 * @list: list to use
2170 * @newsk: buffer to queue
2172 * Queue a buffer at the start of the list. This function takes the
2173 * list lock and can be used safely with other locking &sk_buff functions
2176 * A buffer cannot be placed on two lists at the same time.
2178 void skb_queue_head(struct sk_buff_head
*list
, struct sk_buff
*newsk
)
2180 unsigned long flags
;
2182 spin_lock_irqsave(&list
->lock
, flags
);
2183 __skb_queue_head(list
, newsk
);
2184 spin_unlock_irqrestore(&list
->lock
, flags
);
2186 EXPORT_SYMBOL(skb_queue_head
);
2189 * skb_queue_tail - queue a buffer at the list tail
2190 * @list: list to use
2191 * @newsk: buffer to queue
2193 * Queue a buffer at the tail of the list. This function takes the
2194 * list lock and can be used safely with other locking &sk_buff functions
2197 * A buffer cannot be placed on two lists at the same time.
2199 void skb_queue_tail(struct sk_buff_head
*list
, struct sk_buff
*newsk
)
2201 unsigned long flags
;
2203 spin_lock_irqsave(&list
->lock
, flags
);
2204 __skb_queue_tail(list
, newsk
);
2205 spin_unlock_irqrestore(&list
->lock
, flags
);
2207 EXPORT_SYMBOL(skb_queue_tail
);
2210 * skb_unlink - remove a buffer from a list
2211 * @skb: buffer to remove
2212 * @list: list to use
2214 * Remove a packet from a list. The list locks are taken and this
2215 * function is atomic with respect to other list locked calls
2217 * You must know what list the SKB is on.
2219 void skb_unlink(struct sk_buff
*skb
, struct sk_buff_head
*list
)
2221 unsigned long flags
;
2223 spin_lock_irqsave(&list
->lock
, flags
);
2224 __skb_unlink(skb
, list
);
2225 spin_unlock_irqrestore(&list
->lock
, flags
);
2227 EXPORT_SYMBOL(skb_unlink
);
2230 * skb_append - append a buffer
2231 * @old: buffer to insert after
2232 * @newsk: buffer to insert
2233 * @list: list to use
2235 * Place a packet after a given packet in a list. The list locks are taken
2236 * and this function is atomic with respect to other list locked calls.
2237 * A buffer cannot be placed on two lists at the same time.
2239 void skb_append(struct sk_buff
*old
, struct sk_buff
*newsk
, struct sk_buff_head
*list
)
2241 unsigned long flags
;
2243 spin_lock_irqsave(&list
->lock
, flags
);
2244 __skb_queue_after(list
, old
, newsk
);
2245 spin_unlock_irqrestore(&list
->lock
, flags
);
2247 EXPORT_SYMBOL(skb_append
);
2250 * skb_insert - insert a buffer
2251 * @old: buffer to insert before
2252 * @newsk: buffer to insert
2253 * @list: list to use
2255 * Place a packet before a given packet in a list. The list locks are
2256 * taken and this function is atomic with respect to other list locked
2259 * A buffer cannot be placed on two lists at the same time.
2261 void skb_insert(struct sk_buff
*old
, struct sk_buff
*newsk
, struct sk_buff_head
*list
)
2263 unsigned long flags
;
2265 spin_lock_irqsave(&list
->lock
, flags
);
2266 __skb_insert(newsk
, old
->prev
, old
, list
);
2267 spin_unlock_irqrestore(&list
->lock
, flags
);
2269 EXPORT_SYMBOL(skb_insert
);
2271 static inline void skb_split_inside_header(struct sk_buff
*skb
,
2272 struct sk_buff
* skb1
,
2273 const u32 len
, const int pos
)
2277 skb_copy_from_linear_data_offset(skb
, len
, skb_put(skb1
, pos
- len
),
2279 /* And move data appendix as is. */
2280 for (i
= 0; i
< skb_shinfo(skb
)->nr_frags
; i
++)
2281 skb_shinfo(skb1
)->frags
[i
] = skb_shinfo(skb
)->frags
[i
];
2283 skb_shinfo(skb1
)->nr_frags
= skb_shinfo(skb
)->nr_frags
;
2284 skb_shinfo(skb
)->nr_frags
= 0;
2285 skb1
->data_len
= skb
->data_len
;
2286 skb1
->len
+= skb1
->data_len
;
2289 skb_set_tail_pointer(skb
, len
);
2292 static inline void skb_split_no_header(struct sk_buff
*skb
,
2293 struct sk_buff
* skb1
,
2294 const u32 len
, int pos
)
2297 const int nfrags
= skb_shinfo(skb
)->nr_frags
;
2299 skb_shinfo(skb
)->nr_frags
= 0;
2300 skb1
->len
= skb1
->data_len
= skb
->len
- len
;
2302 skb
->data_len
= len
- pos
;
2304 for (i
= 0; i
< nfrags
; i
++) {
2305 int size
= skb_frag_size(&skb_shinfo(skb
)->frags
[i
]);
2307 if (pos
+ size
> len
) {
2308 skb_shinfo(skb1
)->frags
[k
] = skb_shinfo(skb
)->frags
[i
];
2312 * We have two variants in this case:
2313 * 1. Move all the frag to the second
2314 * part, if it is possible. F.e.
2315 * this approach is mandatory for TUX,
2316 * where splitting is expensive.
2317 * 2. Split is accurately. We make this.
2319 skb_frag_ref(skb
, i
);
2320 skb_shinfo(skb1
)->frags
[0].page_offset
+= len
- pos
;
2321 skb_frag_size_sub(&skb_shinfo(skb1
)->frags
[0], len
- pos
);
2322 skb_frag_size_set(&skb_shinfo(skb
)->frags
[i
], len
- pos
);
2323 skb_shinfo(skb
)->nr_frags
++;
2327 skb_shinfo(skb
)->nr_frags
++;
2330 skb_shinfo(skb1
)->nr_frags
= k
;
2334 * skb_split - Split fragmented skb to two parts at length len.
2335 * @skb: the buffer to split
2336 * @skb1: the buffer to receive the second part
2337 * @len: new length for skb
2339 void skb_split(struct sk_buff
*skb
, struct sk_buff
*skb1
, const u32 len
)
2341 int pos
= skb_headlen(skb
);
2343 if (len
< pos
) /* Split line is inside header. */
2344 skb_split_inside_header(skb
, skb1
, len
, pos
);
2345 else /* Second chunk has no header, nothing to copy. */
2346 skb_split_no_header(skb
, skb1
, len
, pos
);
2348 EXPORT_SYMBOL(skb_split
);
2350 /* Shifting from/to a cloned skb is a no-go.
2352 * Caller cannot keep skb_shinfo related pointers past calling here!
2354 static int skb_prepare_for_shift(struct sk_buff
*skb
)
2356 return skb_cloned(skb
) && pskb_expand_head(skb
, 0, 0, GFP_ATOMIC
);
2360 * skb_shift - Shifts paged data partially from skb to another
2361 * @tgt: buffer into which tail data gets added
2362 * @skb: buffer from which the paged data comes from
2363 * @shiftlen: shift up to this many bytes
2365 * Attempts to shift up to shiftlen worth of bytes, which may be less than
2366 * the length of the skb, from skb to tgt. Returns number bytes shifted.
2367 * It's up to caller to free skb if everything was shifted.
2369 * If @tgt runs out of frags, the whole operation is aborted.
2371 * Skb cannot include anything else but paged data while tgt is allowed
2372 * to have non-paged data as well.
2374 * TODO: full sized shift could be optimized but that would need
2375 * specialized skb free'er to handle frags without up-to-date nr_frags.
2377 int skb_shift(struct sk_buff
*tgt
, struct sk_buff
*skb
, int shiftlen
)
2379 int from
, to
, merge
, todo
;
2380 struct skb_frag_struct
*fragfrom
, *fragto
;
2382 BUG_ON(shiftlen
> skb
->len
);
2383 BUG_ON(skb_headlen(skb
)); /* Would corrupt stream */
2387 to
= skb_shinfo(tgt
)->nr_frags
;
2388 fragfrom
= &skb_shinfo(skb
)->frags
[from
];
2390 /* Actual merge is delayed until the point when we know we can
2391 * commit all, so that we don't have to undo partial changes
2394 !skb_can_coalesce(tgt
, to
, skb_frag_page(fragfrom
),
2395 fragfrom
->page_offset
)) {
2400 todo
-= skb_frag_size(fragfrom
);
2402 if (skb_prepare_for_shift(skb
) ||
2403 skb_prepare_for_shift(tgt
))
2406 /* All previous frag pointers might be stale! */
2407 fragfrom
= &skb_shinfo(skb
)->frags
[from
];
2408 fragto
= &skb_shinfo(tgt
)->frags
[merge
];
2410 skb_frag_size_add(fragto
, shiftlen
);
2411 skb_frag_size_sub(fragfrom
, shiftlen
);
2412 fragfrom
->page_offset
+= shiftlen
;
2420 /* Skip full, not-fitting skb to avoid expensive operations */
2421 if ((shiftlen
== skb
->len
) &&
2422 (skb_shinfo(skb
)->nr_frags
- from
) > (MAX_SKB_FRAGS
- to
))
2425 if (skb_prepare_for_shift(skb
) || skb_prepare_for_shift(tgt
))
2428 while ((todo
> 0) && (from
< skb_shinfo(skb
)->nr_frags
)) {
2429 if (to
== MAX_SKB_FRAGS
)
2432 fragfrom
= &skb_shinfo(skb
)->frags
[from
];
2433 fragto
= &skb_shinfo(tgt
)->frags
[to
];
2435 if (todo
>= skb_frag_size(fragfrom
)) {
2436 *fragto
= *fragfrom
;
2437 todo
-= skb_frag_size(fragfrom
);
2442 __skb_frag_ref(fragfrom
);
2443 fragto
->page
= fragfrom
->page
;
2444 fragto
->page_offset
= fragfrom
->page_offset
;
2445 skb_frag_size_set(fragto
, todo
);
2447 fragfrom
->page_offset
+= todo
;
2448 skb_frag_size_sub(fragfrom
, todo
);
2456 /* Ready to "commit" this state change to tgt */
2457 skb_shinfo(tgt
)->nr_frags
= to
;
2460 fragfrom
= &skb_shinfo(skb
)->frags
[0];
2461 fragto
= &skb_shinfo(tgt
)->frags
[merge
];
2463 skb_frag_size_add(fragto
, skb_frag_size(fragfrom
));
2464 __skb_frag_unref(fragfrom
);
2467 /* Reposition in the original skb */
2469 while (from
< skb_shinfo(skb
)->nr_frags
)
2470 skb_shinfo(skb
)->frags
[to
++] = skb_shinfo(skb
)->frags
[from
++];
2471 skb_shinfo(skb
)->nr_frags
= to
;
2473 BUG_ON(todo
> 0 && !skb_shinfo(skb
)->nr_frags
);
2476 /* Most likely the tgt won't ever need its checksum anymore, skb on
2477 * the other hand might need it if it needs to be resent
2479 tgt
->ip_summed
= CHECKSUM_PARTIAL
;
2480 skb
->ip_summed
= CHECKSUM_PARTIAL
;
2482 /* Yak, is it really working this way? Some helper please? */
2483 skb
->len
-= shiftlen
;
2484 skb
->data_len
-= shiftlen
;
2485 skb
->truesize
-= shiftlen
;
2486 tgt
->len
+= shiftlen
;
2487 tgt
->data_len
+= shiftlen
;
2488 tgt
->truesize
+= shiftlen
;
2494 * skb_prepare_seq_read - Prepare a sequential read of skb data
2495 * @skb: the buffer to read
2496 * @from: lower offset of data to be read
2497 * @to: upper offset of data to be read
2498 * @st: state variable
2500 * Initializes the specified state variable. Must be called before
2501 * invoking skb_seq_read() for the first time.
2503 void skb_prepare_seq_read(struct sk_buff
*skb
, unsigned int from
,
2504 unsigned int to
, struct skb_seq_state
*st
)
2506 st
->lower_offset
= from
;
2507 st
->upper_offset
= to
;
2508 st
->root_skb
= st
->cur_skb
= skb
;
2509 st
->frag_idx
= st
->stepped_offset
= 0;
2510 st
->frag_data
= NULL
;
2512 EXPORT_SYMBOL(skb_prepare_seq_read
);
2515 * skb_seq_read - Sequentially read skb data
2516 * @consumed: number of bytes consumed by the caller so far
2517 * @data: destination pointer for data to be returned
2518 * @st: state variable
2520 * Reads a block of skb data at &consumed relative to the
2521 * lower offset specified to skb_prepare_seq_read(). Assigns
2522 * the head of the data block to &data and returns the length
2523 * of the block or 0 if the end of the skb data or the upper
2524 * offset has been reached.
2526 * The caller is not required to consume all of the data
2527 * returned, i.e. &consumed is typically set to the number
2528 * of bytes already consumed and the next call to
2529 * skb_seq_read() will return the remaining part of the block.
2531 * Note 1: The size of each block of data returned can be arbitrary,
2532 * this limitation is the cost for zerocopy seqeuental
2533 * reads of potentially non linear data.
2535 * Note 2: Fragment lists within fragments are not implemented
2536 * at the moment, state->root_skb could be replaced with
2537 * a stack for this purpose.
2539 unsigned int skb_seq_read(unsigned int consumed
, const u8
**data
,
2540 struct skb_seq_state
*st
)
2542 unsigned int block_limit
, abs_offset
= consumed
+ st
->lower_offset
;
2545 if (unlikely(abs_offset
>= st
->upper_offset
))
2549 block_limit
= skb_headlen(st
->cur_skb
) + st
->stepped_offset
;
2551 if (abs_offset
< block_limit
&& !st
->frag_data
) {
2552 *data
= st
->cur_skb
->data
+ (abs_offset
- st
->stepped_offset
);
2553 return block_limit
- abs_offset
;
2556 if (st
->frag_idx
== 0 && !st
->frag_data
)
2557 st
->stepped_offset
+= skb_headlen(st
->cur_skb
);
2559 while (st
->frag_idx
< skb_shinfo(st
->cur_skb
)->nr_frags
) {
2560 frag
= &skb_shinfo(st
->cur_skb
)->frags
[st
->frag_idx
];
2561 block_limit
= skb_frag_size(frag
) + st
->stepped_offset
;
2563 if (abs_offset
< block_limit
) {
2565 st
->frag_data
= kmap_atomic(skb_frag_page(frag
));
2567 *data
= (u8
*) st
->frag_data
+ frag
->page_offset
+
2568 (abs_offset
- st
->stepped_offset
);
2570 return block_limit
- abs_offset
;
2573 if (st
->frag_data
) {
2574 kunmap_atomic(st
->frag_data
);
2575 st
->frag_data
= NULL
;
2579 st
->stepped_offset
+= skb_frag_size(frag
);
2582 if (st
->frag_data
) {
2583 kunmap_atomic(st
->frag_data
);
2584 st
->frag_data
= NULL
;
2587 if (st
->root_skb
== st
->cur_skb
&& skb_has_frag_list(st
->root_skb
)) {
2588 st
->cur_skb
= skb_shinfo(st
->root_skb
)->frag_list
;
2591 } else if (st
->cur_skb
->next
) {
2592 st
->cur_skb
= st
->cur_skb
->next
;
2599 EXPORT_SYMBOL(skb_seq_read
);
2602 * skb_abort_seq_read - Abort a sequential read of skb data
2603 * @st: state variable
2605 * Must be called if skb_seq_read() was not called until it
2608 void skb_abort_seq_read(struct skb_seq_state
*st
)
2611 kunmap_atomic(st
->frag_data
);
2613 EXPORT_SYMBOL(skb_abort_seq_read
);
2615 #define TS_SKB_CB(state) ((struct skb_seq_state *) &((state)->cb))
2617 static unsigned int skb_ts_get_next_block(unsigned int offset
, const u8
**text
,
2618 struct ts_config
*conf
,
2619 struct ts_state
*state
)
2621 return skb_seq_read(offset
, text
, TS_SKB_CB(state
));
2624 static void skb_ts_finish(struct ts_config
*conf
, struct ts_state
*state
)
2626 skb_abort_seq_read(TS_SKB_CB(state
));
2630 * skb_find_text - Find a text pattern in skb data
2631 * @skb: the buffer to look in
2632 * @from: search offset
2634 * @config: textsearch configuration
2635 * @state: uninitialized textsearch state variable
2637 * Finds a pattern in the skb data according to the specified
2638 * textsearch configuration. Use textsearch_next() to retrieve
2639 * subsequent occurrences of the pattern. Returns the offset
2640 * to the first occurrence or UINT_MAX if no match was found.
2642 unsigned int skb_find_text(struct sk_buff
*skb
, unsigned int from
,
2643 unsigned int to
, struct ts_config
*config
,
2644 struct ts_state
*state
)
2648 config
->get_next_block
= skb_ts_get_next_block
;
2649 config
->finish
= skb_ts_finish
;
2651 skb_prepare_seq_read(skb
, from
, to
, TS_SKB_CB(state
));
2653 ret
= textsearch_find(config
, state
);
2654 return (ret
<= to
- from
? ret
: UINT_MAX
);
2656 EXPORT_SYMBOL(skb_find_text
);
2659 * skb_append_datato_frags - append the user data to a skb
2660 * @sk: sock structure
2661 * @skb: skb structure to be appened with user data.
2662 * @getfrag: call back function to be used for getting the user data
2663 * @from: pointer to user message iov
2664 * @length: length of the iov message
2666 * Description: This procedure append the user data in the fragment part
2667 * of the skb if any page alloc fails user this procedure returns -ENOMEM
2669 int skb_append_datato_frags(struct sock
*sk
, struct sk_buff
*skb
,
2670 int (*getfrag
)(void *from
, char *to
, int offset
,
2671 int len
, int odd
, struct sk_buff
*skb
),
2672 void *from
, int length
)
2674 int frg_cnt
= skb_shinfo(skb
)->nr_frags
;
2678 struct page_frag
*pfrag
= ¤t
->task_frag
;
2681 /* Return error if we don't have space for new frag */
2682 if (frg_cnt
>= MAX_SKB_FRAGS
)
2685 if (!sk_page_frag_refill(sk
, pfrag
))
2688 /* copy the user data to page */
2689 copy
= min_t(int, length
, pfrag
->size
- pfrag
->offset
);
2691 ret
= getfrag(from
, page_address(pfrag
->page
) + pfrag
->offset
,
2692 offset
, copy
, 0, skb
);
2696 /* copy was successful so update the size parameters */
2697 skb_fill_page_desc(skb
, frg_cnt
, pfrag
->page
, pfrag
->offset
,
2700 pfrag
->offset
+= copy
;
2701 get_page(pfrag
->page
);
2703 skb
->truesize
+= copy
;
2704 atomic_add(copy
, &sk
->sk_wmem_alloc
);
2706 skb
->data_len
+= copy
;
2710 } while (length
> 0);
2714 EXPORT_SYMBOL(skb_append_datato_frags
);
2717 * skb_pull_rcsum - pull skb and update receive checksum
2718 * @skb: buffer to update
2719 * @len: length of data pulled
2721 * This function performs an skb_pull on the packet and updates
2722 * the CHECKSUM_COMPLETE checksum. It should be used on
2723 * receive path processing instead of skb_pull unless you know
2724 * that the checksum difference is zero (e.g., a valid IP header)
2725 * or you are setting ip_summed to CHECKSUM_NONE.
2727 unsigned char *skb_pull_rcsum(struct sk_buff
*skb
, unsigned int len
)
2729 BUG_ON(len
> skb
->len
);
2731 BUG_ON(skb
->len
< skb
->data_len
);
2732 skb_postpull_rcsum(skb
, skb
->data
, len
);
2733 return skb
->data
+= len
;
2735 EXPORT_SYMBOL_GPL(skb_pull_rcsum
);
2738 * skb_segment - Perform protocol segmentation on skb.
2739 * @skb: buffer to segment
2740 * @features: features for the output path (see dev->features)
2742 * This function performs segmentation on the given skb. It returns
2743 * a pointer to the first in a list of new skbs for the segments.
2744 * In case of error it returns ERR_PTR(err).
2746 struct sk_buff
*skb_segment(struct sk_buff
*skb
, netdev_features_t features
)
2748 struct sk_buff
*segs
= NULL
;
2749 struct sk_buff
*tail
= NULL
;
2750 struct sk_buff
*fskb
= skb_shinfo(skb
)->frag_list
;
2751 unsigned int mss
= skb_shinfo(skb
)->gso_size
;
2752 unsigned int doffset
= skb
->data
- skb_mac_header(skb
);
2753 unsigned int offset
= doffset
;
2754 unsigned int headroom
;
2756 int sg
= !!(features
& NETIF_F_SG
);
2757 int nfrags
= skb_shinfo(skb
)->nr_frags
;
2762 __skb_push(skb
, doffset
);
2763 headroom
= skb_headroom(skb
);
2764 pos
= skb_headlen(skb
);
2767 struct sk_buff
*nskb
;
2772 len
= skb
->len
- offset
;
2776 hsize
= skb_headlen(skb
) - offset
;
2779 if (hsize
> len
|| !sg
)
2782 if (!hsize
&& i
>= nfrags
) {
2783 BUG_ON(fskb
->len
!= len
);
2786 nskb
= skb_clone(fskb
, GFP_ATOMIC
);
2789 if (unlikely(!nskb
))
2792 hsize
= skb_end_offset(nskb
);
2793 if (skb_cow_head(nskb
, doffset
+ headroom
)) {
2798 nskb
->truesize
+= skb_end_offset(nskb
) - hsize
;
2799 skb_release_head_state(nskb
);
2800 __skb_push(nskb
, doffset
);
2802 nskb
= __alloc_skb(hsize
+ doffset
+ headroom
,
2803 GFP_ATOMIC
, skb_alloc_rx_flag(skb
),
2806 if (unlikely(!nskb
))
2809 skb_reserve(nskb
, headroom
);
2810 __skb_put(nskb
, doffset
);
2819 __copy_skb_header(nskb
, skb
);
2820 nskb
->mac_len
= skb
->mac_len
;
2822 /* nskb and skb might have different headroom */
2823 if (nskb
->ip_summed
== CHECKSUM_PARTIAL
)
2824 nskb
->csum_start
+= skb_headroom(nskb
) - headroom
;
2826 skb_reset_mac_header(nskb
);
2827 skb_set_network_header(nskb
, skb
->mac_len
);
2828 nskb
->transport_header
= (nskb
->network_header
+
2829 skb_network_header_len(skb
));
2830 skb_copy_from_linear_data(skb
, nskb
->data
, doffset
);
2832 if (fskb
!= skb_shinfo(skb
)->frag_list
)
2836 nskb
->ip_summed
= CHECKSUM_NONE
;
2837 nskb
->csum
= skb_copy_and_csum_bits(skb
, offset
,
2843 frag
= skb_shinfo(nskb
)->frags
;
2845 skb_copy_from_linear_data_offset(skb
, offset
,
2846 skb_put(nskb
, hsize
), hsize
);
2848 while (pos
< offset
+ len
&& i
< nfrags
) {
2849 *frag
= skb_shinfo(skb
)->frags
[i
];
2850 __skb_frag_ref(frag
);
2851 size
= skb_frag_size(frag
);
2854 frag
->page_offset
+= offset
- pos
;
2855 skb_frag_size_sub(frag
, offset
- pos
);
2858 skb_shinfo(nskb
)->nr_frags
++;
2860 if (pos
+ size
<= offset
+ len
) {
2864 skb_frag_size_sub(frag
, pos
+ size
- (offset
+ len
));
2871 if (pos
< offset
+ len
) {
2872 struct sk_buff
*fskb2
= fskb
;
2874 BUG_ON(pos
+ fskb
->len
!= offset
+ len
);
2880 fskb2
= skb_clone(fskb2
, GFP_ATOMIC
);
2886 SKB_FRAG_ASSERT(nskb
);
2887 skb_shinfo(nskb
)->frag_list
= fskb2
;
2891 nskb
->data_len
= len
- hsize
;
2892 nskb
->len
+= nskb
->data_len
;
2893 nskb
->truesize
+= nskb
->data_len
;
2894 } while ((offset
+= len
) < skb
->len
);
2899 while ((skb
= segs
)) {
2903 return ERR_PTR(err
);
2905 EXPORT_SYMBOL_GPL(skb_segment
);
2907 int skb_gro_receive(struct sk_buff
**head
, struct sk_buff
*skb
)
2909 struct sk_buff
*p
= *head
;
2910 struct sk_buff
*nskb
;
2911 struct skb_shared_info
*skbinfo
= skb_shinfo(skb
);
2912 struct skb_shared_info
*pinfo
= skb_shinfo(p
);
2913 unsigned int headroom
;
2914 unsigned int len
= skb_gro_len(skb
);
2915 unsigned int offset
= skb_gro_offset(skb
);
2916 unsigned int headlen
= skb_headlen(skb
);
2917 unsigned int delta_truesize
;
2919 if (p
->len
+ len
>= 65536)
2922 if (pinfo
->frag_list
)
2924 else if (headlen
<= offset
) {
2927 int i
= skbinfo
->nr_frags
;
2928 int nr_frags
= pinfo
->nr_frags
+ i
;
2932 if (nr_frags
> MAX_SKB_FRAGS
)
2935 pinfo
->nr_frags
= nr_frags
;
2936 skbinfo
->nr_frags
= 0;
2938 frag
= pinfo
->frags
+ nr_frags
;
2939 frag2
= skbinfo
->frags
+ i
;
2944 frag
->page_offset
+= offset
;
2945 skb_frag_size_sub(frag
, offset
);
2947 /* all fragments truesize : remove (head size + sk_buff) */
2948 delta_truesize
= skb
->truesize
-
2949 SKB_TRUESIZE(skb_end_offset(skb
));
2951 skb
->truesize
-= skb
->data_len
;
2952 skb
->len
-= skb
->data_len
;
2955 NAPI_GRO_CB(skb
)->free
= NAPI_GRO_FREE
;
2957 } else if (skb
->head_frag
) {
2958 int nr_frags
= pinfo
->nr_frags
;
2959 skb_frag_t
*frag
= pinfo
->frags
+ nr_frags
;
2960 struct page
*page
= virt_to_head_page(skb
->head
);
2961 unsigned int first_size
= headlen
- offset
;
2962 unsigned int first_offset
;
2964 if (nr_frags
+ 1 + skbinfo
->nr_frags
> MAX_SKB_FRAGS
)
2967 first_offset
= skb
->data
-
2968 (unsigned char *)page_address(page
) +
2971 pinfo
->nr_frags
= nr_frags
+ 1 + skbinfo
->nr_frags
;
2973 frag
->page
.p
= page
;
2974 frag
->page_offset
= first_offset
;
2975 skb_frag_size_set(frag
, first_size
);
2977 memcpy(frag
+ 1, skbinfo
->frags
, sizeof(*frag
) * skbinfo
->nr_frags
);
2978 /* We dont need to clear skbinfo->nr_frags here */
2980 delta_truesize
= skb
->truesize
- SKB_DATA_ALIGN(sizeof(struct sk_buff
));
2981 NAPI_GRO_CB(skb
)->free
= NAPI_GRO_FREE_STOLEN_HEAD
;
2983 } else if (skb_gro_len(p
) != pinfo
->gso_size
)
2986 headroom
= skb_headroom(p
);
2987 nskb
= alloc_skb(headroom
+ skb_gro_offset(p
), GFP_ATOMIC
);
2988 if (unlikely(!nskb
))
2991 __copy_skb_header(nskb
, p
);
2992 nskb
->mac_len
= p
->mac_len
;
2994 skb_reserve(nskb
, headroom
);
2995 __skb_put(nskb
, skb_gro_offset(p
));
2997 skb_set_mac_header(nskb
, skb_mac_header(p
) - p
->data
);
2998 skb_set_network_header(nskb
, skb_network_offset(p
));
2999 skb_set_transport_header(nskb
, skb_transport_offset(p
));
3001 __skb_pull(p
, skb_gro_offset(p
));
3002 memcpy(skb_mac_header(nskb
), skb_mac_header(p
),
3003 p
->data
- skb_mac_header(p
));
3005 skb_shinfo(nskb
)->frag_list
= p
;
3006 skb_shinfo(nskb
)->gso_size
= pinfo
->gso_size
;
3007 pinfo
->gso_size
= 0;
3008 skb_header_release(p
);
3009 NAPI_GRO_CB(nskb
)->last
= p
;
3011 nskb
->data_len
+= p
->len
;
3012 nskb
->truesize
+= p
->truesize
;
3013 nskb
->len
+= p
->len
;
3016 nskb
->next
= p
->next
;
3022 delta_truesize
= skb
->truesize
;
3023 if (offset
> headlen
) {
3024 unsigned int eat
= offset
- headlen
;
3026 skbinfo
->frags
[0].page_offset
+= eat
;
3027 skb_frag_size_sub(&skbinfo
->frags
[0], eat
);
3028 skb
->data_len
-= eat
;
3033 __skb_pull(skb
, offset
);
3035 NAPI_GRO_CB(p
)->last
->next
= skb
;
3036 NAPI_GRO_CB(p
)->last
= skb
;
3037 skb_header_release(skb
);
3040 NAPI_GRO_CB(p
)->count
++;
3042 p
->truesize
+= delta_truesize
;
3045 NAPI_GRO_CB(skb
)->same_flow
= 1;
3048 EXPORT_SYMBOL_GPL(skb_gro_receive
);
3050 void __init
skb_init(void)
3052 skbuff_head_cache
= kmem_cache_create("skbuff_head_cache",
3053 sizeof(struct sk_buff
),
3055 SLAB_HWCACHE_ALIGN
|SLAB_PANIC
,
3057 skbuff_fclone_cache
= kmem_cache_create("skbuff_fclone_cache",
3058 (2*sizeof(struct sk_buff
)) +
3061 SLAB_HWCACHE_ALIGN
|SLAB_PANIC
,
3066 * skb_to_sgvec - Fill a scatter-gather list from a socket buffer
3067 * @skb: Socket buffer containing the buffers to be mapped
3068 * @sg: The scatter-gather list to map into
3069 * @offset: The offset into the buffer's contents to start mapping
3070 * @len: Length of buffer space to be mapped
3072 * Fill the specified scatter-gather list with mappings/pointers into a
3073 * region of the buffer space attached to a socket buffer.
3076 __skb_to_sgvec(struct sk_buff
*skb
, struct scatterlist
*sg
, int offset
, int len
)
3078 int start
= skb_headlen(skb
);
3079 int i
, copy
= start
- offset
;
3080 struct sk_buff
*frag_iter
;
3086 sg_set_buf(sg
, skb
->data
+ offset
, copy
);
3088 if ((len
-= copy
) == 0)
3093 for (i
= 0; i
< skb_shinfo(skb
)->nr_frags
; i
++) {
3096 WARN_ON(start
> offset
+ len
);
3098 end
= start
+ skb_frag_size(&skb_shinfo(skb
)->frags
[i
]);
3099 if ((copy
= end
- offset
) > 0) {
3100 skb_frag_t
*frag
= &skb_shinfo(skb
)->frags
[i
];
3104 sg_set_page(&sg
[elt
], skb_frag_page(frag
), copy
,
3105 frag
->page_offset
+offset
-start
);
3114 skb_walk_frags(skb
, frag_iter
) {
3117 WARN_ON(start
> offset
+ len
);
3119 end
= start
+ frag_iter
->len
;
3120 if ((copy
= end
- offset
) > 0) {
3123 elt
+= __skb_to_sgvec(frag_iter
, sg
+elt
, offset
- start
,
3125 if ((len
-= copy
) == 0)
3135 int skb_to_sgvec(struct sk_buff
*skb
, struct scatterlist
*sg
, int offset
, int len
)
3137 int nsg
= __skb_to_sgvec(skb
, sg
, offset
, len
);
3139 sg_mark_end(&sg
[nsg
- 1]);
3143 EXPORT_SYMBOL_GPL(skb_to_sgvec
);
3146 * skb_cow_data - Check that a socket buffer's data buffers are writable
3147 * @skb: The socket buffer to check.
3148 * @tailbits: Amount of trailing space to be added
3149 * @trailer: Returned pointer to the skb where the @tailbits space begins
3151 * Make sure that the data buffers attached to a socket buffer are
3152 * writable. If they are not, private copies are made of the data buffers
3153 * and the socket buffer is set to use these instead.
3155 * If @tailbits is given, make sure that there is space to write @tailbits
3156 * bytes of data beyond current end of socket buffer. @trailer will be
3157 * set to point to the skb in which this space begins.
3159 * The number of scatterlist elements required to completely map the
3160 * COW'd and extended socket buffer will be returned.
3162 int skb_cow_data(struct sk_buff
*skb
, int tailbits
, struct sk_buff
**trailer
)
3166 struct sk_buff
*skb1
, **skb_p
;
3168 /* If skb is cloned or its head is paged, reallocate
3169 * head pulling out all the pages (pages are considered not writable
3170 * at the moment even if they are anonymous).
3172 if ((skb_cloned(skb
) || skb_shinfo(skb
)->nr_frags
) &&
3173 __pskb_pull_tail(skb
, skb_pagelen(skb
)-skb_headlen(skb
)) == NULL
)
3176 /* Easy case. Most of packets will go this way. */
3177 if (!skb_has_frag_list(skb
)) {
3178 /* A little of trouble, not enough of space for trailer.
3179 * This should not happen, when stack is tuned to generate
3180 * good frames. OK, on miss we reallocate and reserve even more
3181 * space, 128 bytes is fair. */
3183 if (skb_tailroom(skb
) < tailbits
&&
3184 pskb_expand_head(skb
, 0, tailbits
-skb_tailroom(skb
)+128, GFP_ATOMIC
))
3192 /* Misery. We are in troubles, going to mincer fragments... */
3195 skb_p
= &skb_shinfo(skb
)->frag_list
;
3198 while ((skb1
= *skb_p
) != NULL
) {
3201 /* The fragment is partially pulled by someone,
3202 * this can happen on input. Copy it and everything
3205 if (skb_shared(skb1
))
3208 /* If the skb is the last, worry about trailer. */
3210 if (skb1
->next
== NULL
&& tailbits
) {
3211 if (skb_shinfo(skb1
)->nr_frags
||
3212 skb_has_frag_list(skb1
) ||
3213 skb_tailroom(skb1
) < tailbits
)
3214 ntail
= tailbits
+ 128;
3220 skb_shinfo(skb1
)->nr_frags
||
3221 skb_has_frag_list(skb1
)) {
3222 struct sk_buff
*skb2
;
3224 /* Fuck, we are miserable poor guys... */
3226 skb2
= skb_copy(skb1
, GFP_ATOMIC
);
3228 skb2
= skb_copy_expand(skb1
,
3232 if (unlikely(skb2
== NULL
))
3236 skb_set_owner_w(skb2
, skb1
->sk
);
3238 /* Looking around. Are we still alive?
3239 * OK, link new skb, drop old one */
3241 skb2
->next
= skb1
->next
;
3248 skb_p
= &skb1
->next
;
3253 EXPORT_SYMBOL_GPL(skb_cow_data
);
3255 static void sock_rmem_free(struct sk_buff
*skb
)
3257 struct sock
*sk
= skb
->sk
;
3259 atomic_sub(skb
->truesize
, &sk
->sk_rmem_alloc
);
3263 * Note: We dont mem charge error packets (no sk_forward_alloc changes)
3265 int sock_queue_err_skb(struct sock
*sk
, struct sk_buff
*skb
)
3269 if (atomic_read(&sk
->sk_rmem_alloc
) + skb
->truesize
>=
3270 (unsigned int)sk
->sk_rcvbuf
)
3275 skb
->destructor
= sock_rmem_free
;
3276 atomic_add(skb
->truesize
, &sk
->sk_rmem_alloc
);
3278 /* before exiting rcu section, make sure dst is refcounted */
3281 skb_queue_tail(&sk
->sk_error_queue
, skb
);
3282 if (!sock_flag(sk
, SOCK_DEAD
))
3283 sk
->sk_data_ready(sk
, len
);
3286 EXPORT_SYMBOL(sock_queue_err_skb
);
3288 void skb_tstamp_tx(struct sk_buff
*orig_skb
,
3289 struct skb_shared_hwtstamps
*hwtstamps
)
3291 struct sock
*sk
= orig_skb
->sk
;
3292 struct sock_exterr_skb
*serr
;
3293 struct sk_buff
*skb
;
3299 skb
= skb_clone(orig_skb
, GFP_ATOMIC
);
3304 *skb_hwtstamps(skb
) =
3308 * no hardware time stamps available,
3309 * so keep the shared tx_flags and only
3310 * store software time stamp
3312 skb
->tstamp
= ktime_get_real();
3315 serr
= SKB_EXT_ERR(skb
);
3316 memset(serr
, 0, sizeof(*serr
));
3317 serr
->ee
.ee_errno
= ENOMSG
;
3318 serr
->ee
.ee_origin
= SO_EE_ORIGIN_TIMESTAMPING
;
3320 err
= sock_queue_err_skb(sk
, skb
);
3325 EXPORT_SYMBOL_GPL(skb_tstamp_tx
);
3327 void skb_complete_wifi_ack(struct sk_buff
*skb
, bool acked
)
3329 struct sock
*sk
= skb
->sk
;
3330 struct sock_exterr_skb
*serr
;
3333 skb
->wifi_acked_valid
= 1;
3334 skb
->wifi_acked
= acked
;
3336 serr
= SKB_EXT_ERR(skb
);
3337 memset(serr
, 0, sizeof(*serr
));
3338 serr
->ee
.ee_errno
= ENOMSG
;
3339 serr
->ee
.ee_origin
= SO_EE_ORIGIN_TXSTATUS
;
3341 err
= sock_queue_err_skb(sk
, skb
);
3345 EXPORT_SYMBOL_GPL(skb_complete_wifi_ack
);
3349 * skb_partial_csum_set - set up and verify partial csum values for packet
3350 * @skb: the skb to set
3351 * @start: the number of bytes after skb->data to start checksumming.
3352 * @off: the offset from start to place the checksum.
3354 * For untrusted partially-checksummed packets, we need to make sure the values
3355 * for skb->csum_start and skb->csum_offset are valid so we don't oops.
3357 * This function checks and sets those values and skb->ip_summed: if this
3358 * returns false you should drop the packet.
3360 bool skb_partial_csum_set(struct sk_buff
*skb
, u16 start
, u16 off
)
3362 if (unlikely(start
> skb_headlen(skb
)) ||
3363 unlikely((int)start
+ off
> skb_headlen(skb
) - 2)) {
3364 net_warn_ratelimited("bad partial csum: csum=%u/%u len=%u\n",
3365 start
, off
, skb_headlen(skb
));
3368 skb
->ip_summed
= CHECKSUM_PARTIAL
;
3369 skb
->csum_start
= skb_headroom(skb
) + start
;
3370 skb
->csum_offset
= off
;
3373 EXPORT_SYMBOL_GPL(skb_partial_csum_set
);
3375 void __skb_warn_lro_forwarding(const struct sk_buff
*skb
)
3377 net_warn_ratelimited("%s: received packets cannot be forwarded while LRO is enabled\n",
3380 EXPORT_SYMBOL(__skb_warn_lro_forwarding
);
3382 void kfree_skb_partial(struct sk_buff
*skb
, bool head_stolen
)
3385 skb_release_head_state(skb
);
3386 kmem_cache_free(skbuff_head_cache
, skb
);
3391 EXPORT_SYMBOL(kfree_skb_partial
);
3394 * skb_try_coalesce - try to merge skb to prior one
3396 * @from: buffer to add
3397 * @fragstolen: pointer to boolean
3398 * @delta_truesize: how much more was allocated than was requested
3400 bool skb_try_coalesce(struct sk_buff
*to
, struct sk_buff
*from
,
3401 bool *fragstolen
, int *delta_truesize
)
3403 int i
, delta
, len
= from
->len
;
3405 *fragstolen
= false;
3410 if (len
<= skb_tailroom(to
)) {
3411 BUG_ON(skb_copy_bits(from
, 0, skb_put(to
, len
), len
));
3412 *delta_truesize
= 0;
3416 if (skb_has_frag_list(to
) || skb_has_frag_list(from
))
3419 if (skb_headlen(from
) != 0) {
3421 unsigned int offset
;
3423 if (skb_shinfo(to
)->nr_frags
+
3424 skb_shinfo(from
)->nr_frags
>= MAX_SKB_FRAGS
)
3427 if (skb_head_is_locked(from
))
3430 delta
= from
->truesize
- SKB_DATA_ALIGN(sizeof(struct sk_buff
));
3432 page
= virt_to_head_page(from
->head
);
3433 offset
= from
->data
- (unsigned char *)page_address(page
);
3435 skb_fill_page_desc(to
, skb_shinfo(to
)->nr_frags
,
3436 page
, offset
, skb_headlen(from
));
3439 if (skb_shinfo(to
)->nr_frags
+
3440 skb_shinfo(from
)->nr_frags
> MAX_SKB_FRAGS
)
3443 delta
= from
->truesize
- SKB_TRUESIZE(skb_end_offset(from
));
3446 WARN_ON_ONCE(delta
< len
);
3448 memcpy(skb_shinfo(to
)->frags
+ skb_shinfo(to
)->nr_frags
,
3449 skb_shinfo(from
)->frags
,
3450 skb_shinfo(from
)->nr_frags
* sizeof(skb_frag_t
));
3451 skb_shinfo(to
)->nr_frags
+= skb_shinfo(from
)->nr_frags
;
3453 if (!skb_cloned(from
))
3454 skb_shinfo(from
)->nr_frags
= 0;
3456 /* if the skb is not cloned this does nothing
3457 * since we set nr_frags to 0.
3459 for (i
= 0; i
< skb_shinfo(from
)->nr_frags
; i
++)
3460 skb_frag_ref(from
, i
);
3462 to
->truesize
+= delta
;
3464 to
->data_len
+= len
;
3466 *delta_truesize
= delta
;
3469 EXPORT_SYMBOL(skb_try_coalesce
);