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38
39#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
40
41#include <linux/module.h>
42#include <linux/types.h>
43#include <linux/kernel.h>
44#include <linux/kmemcheck.h>
45#include <linux/mm.h>
46#include <linux/interrupt.h>
47#include <linux/in.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>
55#endif
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>
66
67#include <net/protocol.h>
68#include <net/dst.h>
69#include <net/sock.h>
70#include <net/checksum.h>
71#include <net/ip6_checksum.h>
72#include <net/xfrm.h>
73
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>
79
80struct kmem_cache *skbuff_head_cache __read_mostly;
81static struct kmem_cache *skbuff_fclone_cache __read_mostly;
82
83
84
85
86
87
88
89
90
91
92
93
94
95static void skb_panic(struct sk_buff *skb, unsigned int sz, void *addr,
96 const char msg[])
97{
98 pr_emerg("%s: text:%p len:%d put:%d head:%p data:%p tail:%#lx end:%#lx dev:%s\n",
99 msg, addr, skb->len, sz, skb->head, skb->data,
100 (unsigned long)skb->tail, (unsigned long)skb->end,
101 skb->dev ? skb->dev->name : "<NULL>");
102 BUG();
103}
104
105static void skb_over_panic(struct sk_buff *skb, unsigned int sz, void *addr)
106{
107 skb_panic(skb, sz, addr, __func__);
108}
109
110static void skb_under_panic(struct sk_buff *skb, unsigned int sz, void *addr)
111{
112 skb_panic(skb, sz, addr, __func__);
113}
114
115
116
117
118
119
120
121
122#define kmalloc_reserve(size, gfp, node, pfmemalloc) \
123 __kmalloc_reserve(size, gfp, node, _RET_IP_, pfmemalloc)
124
125static void *__kmalloc_reserve(size_t size, gfp_t flags, int node,
126 unsigned long ip, bool *pfmemalloc)
127{
128 void *obj;
129 bool ret_pfmemalloc = false;
130
131
132
133
134
135 obj = kmalloc_node_track_caller(size,
136 flags | __GFP_NOMEMALLOC | __GFP_NOWARN,
137 node);
138 if (obj || !(gfp_pfmemalloc_allowed(flags)))
139 goto out;
140
141
142 ret_pfmemalloc = true;
143 obj = kmalloc_node_track_caller(size, flags, node);
144
145out:
146 if (pfmemalloc)
147 *pfmemalloc = ret_pfmemalloc;
148
149 return obj;
150}
151
152
153
154
155
156
157
158struct sk_buff *__alloc_skb_head(gfp_t gfp_mask, int node)
159{
160 struct sk_buff *skb;
161
162
163 skb = kmem_cache_alloc_node(skbuff_head_cache,
164 gfp_mask & ~__GFP_DMA, node);
165 if (!skb)
166 goto out;
167
168
169
170
171
172
173 memset(skb, 0, offsetof(struct sk_buff, tail));
174 skb->head = NULL;
175 skb->truesize = sizeof(struct sk_buff);
176 atomic_set(&skb->users, 1);
177
178 skb->mac_header = (typeof(skb->mac_header))~0U;
179out:
180 return skb;
181}
182
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198
199
200struct sk_buff *__alloc_skb(unsigned int size, gfp_t gfp_mask,
201 int flags, int node)
202{
203 struct kmem_cache *cache;
204 struct skb_shared_info *shinfo;
205 struct sk_buff *skb;
206 u8 *data;
207 bool pfmemalloc;
208
209 cache = (flags & SKB_ALLOC_FCLONE)
210 ? skbuff_fclone_cache : skbuff_head_cache;
211
212 if (sk_memalloc_socks() && (flags & SKB_ALLOC_RX))
213 gfp_mask |= __GFP_MEMALLOC;
214
215
216 skb = kmem_cache_alloc_node(cache, gfp_mask & ~__GFP_DMA, node);
217 if (!skb)
218 goto out;
219 prefetchw(skb);
220
221
222
223
224
225
226 size = SKB_DATA_ALIGN(size);
227 size += SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
228 data = kmalloc_reserve(size, gfp_mask, node, &pfmemalloc);
229 if (!data)
230 goto nodata;
231
232
233
234
235 size = SKB_WITH_OVERHEAD(ksize(data));
236 prefetchw(data + size);
237
238
239
240
241
242
243 memset(skb, 0, offsetof(struct sk_buff, tail));
244
245 skb->truesize = SKB_TRUESIZE(size);
246 skb->pfmemalloc = pfmemalloc;
247 atomic_set(&skb->users, 1);
248 skb->head = data;
249 skb->data = data;
250 skb_reset_tail_pointer(skb);
251 skb->end = skb->tail + size;
252 skb->mac_header = (typeof(skb->mac_header))~0U;
253 skb->transport_header = (typeof(skb->transport_header))~0U;
254
255
256 shinfo = skb_shinfo(skb);
257 memset(shinfo, 0, offsetof(struct skb_shared_info, dataref));
258 atomic_set(&shinfo->dataref, 1);
259 kmemcheck_annotate_variable(shinfo->destructor_arg);
260
261 if (flags & SKB_ALLOC_FCLONE) {
262 struct sk_buff_fclones *fclones;
263
264 fclones = container_of(skb, struct sk_buff_fclones, skb1);
265
266 kmemcheck_annotate_bitfield(&fclones->skb2, flags1);
267 skb->fclone = SKB_FCLONE_ORIG;
268 atomic_set(&fclones->fclone_ref, 1);
269
270 fclones->skb2.fclone = SKB_FCLONE_CLONE;
271 fclones->skb2.pfmemalloc = pfmemalloc;
272 }
273out:
274 return skb;
275nodata:
276 kmem_cache_free(cache, skb);
277 skb = NULL;
278 goto out;
279}
280EXPORT_SYMBOL(__alloc_skb);
281
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300
301struct sk_buff *__build_skb(void *data, unsigned int frag_size)
302{
303 struct skb_shared_info *shinfo;
304 struct sk_buff *skb;
305 unsigned int size = frag_size ? : ksize(data);
306
307 skb = kmem_cache_alloc(skbuff_head_cache, GFP_ATOMIC);
308 if (!skb)
309 return NULL;
310
311 size -= SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
312
313 memset(skb, 0, offsetof(struct sk_buff, tail));
314 skb->truesize = SKB_TRUESIZE(size);
315 atomic_set(&skb->users, 1);
316 skb->head = data;
317 skb->data = data;
318 skb_reset_tail_pointer(skb);
319 skb->end = skb->tail + size;
320 skb->mac_header = (typeof(skb->mac_header))~0U;
321 skb->transport_header = (typeof(skb->transport_header))~0U;
322
323
324 shinfo = skb_shinfo(skb);
325 memset(shinfo, 0, offsetof(struct skb_shared_info, dataref));
326 atomic_set(&shinfo->dataref, 1);
327 kmemcheck_annotate_variable(shinfo->destructor_arg);
328
329 return skb;
330}
331
332
333
334
335
336
337struct sk_buff *build_skb(void *data, unsigned int frag_size)
338{
339 struct sk_buff *skb = __build_skb(data, frag_size);
340
341 if (skb && frag_size) {
342 skb->head_frag = 1;
343 if (virt_to_head_page(data)->pfmemalloc)
344 skb->pfmemalloc = 1;
345 }
346 return skb;
347}
348EXPORT_SYMBOL(build_skb);
349
350struct netdev_alloc_cache {
351 struct page_frag frag;
352
353
354
355 unsigned int pagecnt_bias;
356};
357static DEFINE_PER_CPU(struct netdev_alloc_cache, netdev_alloc_cache);
358static DEFINE_PER_CPU(struct netdev_alloc_cache, napi_alloc_cache);
359
360static struct page *__page_frag_refill(struct netdev_alloc_cache *nc,
361 gfp_t gfp_mask)
362{
363 const unsigned int order = NETDEV_FRAG_PAGE_MAX_ORDER;
364 struct page *page = NULL;
365 gfp_t gfp = gfp_mask;
366
367 if (order) {
368 gfp_mask |= __GFP_COMP | __GFP_NOWARN | __GFP_NORETRY |
369 __GFP_NOMEMALLOC;
370 page = alloc_pages_node(NUMA_NO_NODE, gfp_mask, order);
371 nc->frag.size = PAGE_SIZE << (page ? order : 0);
372 }
373
374 if (unlikely(!page))
375 page = alloc_pages_node(NUMA_NO_NODE, gfp, 0);
376
377 nc->frag.page = page;
378
379 return page;
380}
381
382static void *__alloc_page_frag(struct netdev_alloc_cache __percpu *cache,
383 unsigned int fragsz, gfp_t gfp_mask)
384{
385 struct netdev_alloc_cache *nc = this_cpu_ptr(cache);
386 struct page *page = nc->frag.page;
387 unsigned int size;
388 int offset;
389
390 if (unlikely(!page)) {
391refill:
392 page = __page_frag_refill(nc, gfp_mask);
393 if (!page)
394 return NULL;
395
396
397 size = NETDEV_FRAG_PAGE_MAX_ORDER ? nc->frag.size : PAGE_SIZE;
398
399
400
401
402 atomic_add(size - 1, &page->_count);
403
404
405 nc->pagecnt_bias = size;
406 nc->frag.offset = size;
407 }
408
409 offset = nc->frag.offset - fragsz;
410 if (unlikely(offset < 0)) {
411 if (!atomic_sub_and_test(nc->pagecnt_bias, &page->_count))
412 goto refill;
413
414
415 size = NETDEV_FRAG_PAGE_MAX_ORDER ? nc->frag.size : PAGE_SIZE;
416
417
418 atomic_set(&page->_count, size);
419
420
421 nc->pagecnt_bias = size;
422 offset = size - fragsz;
423 }
424
425 nc->pagecnt_bias--;
426 nc->frag.offset = offset;
427
428 return page_address(page) + offset;
429}
430
431static void *__netdev_alloc_frag(unsigned int fragsz, gfp_t gfp_mask)
432{
433 unsigned long flags;
434 void *data;
435
436 local_irq_save(flags);
437 data = __alloc_page_frag(&netdev_alloc_cache, fragsz, gfp_mask);
438 local_irq_restore(flags);
439 return data;
440}
441
442
443
444
445
446
447
448
449void *netdev_alloc_frag(unsigned int fragsz)
450{
451 return __netdev_alloc_frag(fragsz, GFP_ATOMIC | __GFP_COLD);
452}
453EXPORT_SYMBOL(netdev_alloc_frag);
454
455static void *__napi_alloc_frag(unsigned int fragsz, gfp_t gfp_mask)
456{
457 return __alloc_page_frag(&napi_alloc_cache, fragsz, gfp_mask);
458}
459
460void *napi_alloc_frag(unsigned int fragsz)
461{
462 return __napi_alloc_frag(fragsz, GFP_ATOMIC | __GFP_COLD);
463}
464EXPORT_SYMBOL(napi_alloc_frag);
465
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480
481
482static struct sk_buff *__alloc_rx_skb(unsigned int length, gfp_t gfp_mask,
483 int flags)
484{
485 struct sk_buff *skb = NULL;
486 unsigned int fragsz = SKB_DATA_ALIGN(length) +
487 SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
488
489 if (fragsz <= PAGE_SIZE && !(gfp_mask & (__GFP_WAIT | GFP_DMA))) {
490 void *data;
491
492 if (sk_memalloc_socks())
493 gfp_mask |= __GFP_MEMALLOC;
494
495 data = (flags & SKB_ALLOC_NAPI) ?
496 __napi_alloc_frag(fragsz, gfp_mask) :
497 __netdev_alloc_frag(fragsz, gfp_mask);
498
499 if (likely(data)) {
500 skb = build_skb(data, fragsz);
501 if (unlikely(!skb))
502 put_page(virt_to_head_page(data));
503 }
504 } else {
505 skb = __alloc_skb(length, gfp_mask,
506 SKB_ALLOC_RX, NUMA_NO_NODE);
507 }
508 return skb;
509}
510
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522
523
524struct sk_buff *__netdev_alloc_skb(struct net_device *dev,
525 unsigned int length, gfp_t gfp_mask)
526{
527 struct sk_buff *skb;
528
529 length += NET_SKB_PAD;
530 skb = __alloc_rx_skb(length, gfp_mask, 0);
531
532 if (likely(skb)) {
533 skb_reserve(skb, NET_SKB_PAD);
534 skb->dev = dev;
535 }
536
537 return skb;
538}
539EXPORT_SYMBOL(__netdev_alloc_skb);
540
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552
553
554struct sk_buff *__napi_alloc_skb(struct napi_struct *napi,
555 unsigned int length, gfp_t gfp_mask)
556{
557 struct sk_buff *skb;
558
559 length += NET_SKB_PAD + NET_IP_ALIGN;
560 skb = __alloc_rx_skb(length, gfp_mask, SKB_ALLOC_NAPI);
561
562 if (likely(skb)) {
563 skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN);
564 skb->dev = napi->dev;
565 }
566
567 return skb;
568}
569EXPORT_SYMBOL(__napi_alloc_skb);
570
571void skb_add_rx_frag(struct sk_buff *skb, int i, struct page *page, int off,
572 int size, unsigned int truesize)
573{
574 skb_fill_page_desc(skb, i, page, off, size);
575 skb->len += size;
576 skb->data_len += size;
577 skb->truesize += truesize;
578}
579EXPORT_SYMBOL(skb_add_rx_frag);
580
581void skb_coalesce_rx_frag(struct sk_buff *skb, int i, int size,
582 unsigned int truesize)
583{
584 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
585
586 skb_frag_size_add(frag, size);
587 skb->len += size;
588 skb->data_len += size;
589 skb->truesize += truesize;
590}
591EXPORT_SYMBOL(skb_coalesce_rx_frag);
592
593static void skb_drop_list(struct sk_buff **listp)
594{
595 kfree_skb_list(*listp);
596 *listp = NULL;
597}
598
599static inline void skb_drop_fraglist(struct sk_buff *skb)
600{
601 skb_drop_list(&skb_shinfo(skb)->frag_list);
602}
603
604static void skb_clone_fraglist(struct sk_buff *skb)
605{
606 struct sk_buff *list;
607
608 skb_walk_frags(skb, list)
609 skb_get(list);
610}
611
612static void skb_free_head(struct sk_buff *skb)
613{
614 if (skb->head_frag)
615 put_page(virt_to_head_page(skb->head));
616 else
617 kfree(skb->head);
618}
619
620static void skb_release_data(struct sk_buff *skb)
621{
622 struct skb_shared_info *shinfo = skb_shinfo(skb);
623 int i;
624
625 if (skb->cloned &&
626 atomic_sub_return(skb->nohdr ? (1 << SKB_DATAREF_SHIFT) + 1 : 1,
627 &shinfo->dataref))
628 return;
629
630 for (i = 0; i < shinfo->nr_frags; i++)
631 __skb_frag_unref(&shinfo->frags[i]);
632
633
634
635
636
637 if (shinfo->tx_flags & SKBTX_DEV_ZEROCOPY) {
638 struct ubuf_info *uarg;
639
640 uarg = shinfo->destructor_arg;
641 if (uarg->callback)
642 uarg->callback(uarg, true);
643 }
644
645 if (shinfo->frag_list)
646 kfree_skb_list(shinfo->frag_list);
647
648 skb_free_head(skb);
649}
650
651
652
653
654static void kfree_skbmem(struct sk_buff *skb)
655{
656 struct sk_buff_fclones *fclones;
657
658 switch (skb->fclone) {
659 case SKB_FCLONE_UNAVAILABLE:
660 kmem_cache_free(skbuff_head_cache, skb);
661 return;
662
663 case SKB_FCLONE_ORIG:
664 fclones = container_of(skb, struct sk_buff_fclones, skb1);
665
666
667
668
669
670 if (atomic_read(&fclones->fclone_ref) == 1)
671 goto fastpath;
672 break;
673
674 default:
675 fclones = container_of(skb, struct sk_buff_fclones, skb2);
676 break;
677 }
678 if (!atomic_dec_and_test(&fclones->fclone_ref))
679 return;
680fastpath:
681 kmem_cache_free(skbuff_fclone_cache, fclones);
682}
683
684static void skb_release_head_state(struct sk_buff *skb)
685{
686 skb_dst_drop(skb);
687#ifdef CONFIG_XFRM
688 secpath_put(skb->sp);
689#endif
690 if (skb->destructor) {
691 WARN_ON(in_irq());
692 skb->destructor(skb);
693 }
694#if IS_ENABLED(CONFIG_NF_CONNTRACK)
695 nf_conntrack_put(skb->nfct);
696#endif
697#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
698 nf_bridge_put(skb->nf_bridge);
699#endif
700}
701
702
703static void skb_release_all(struct sk_buff *skb)
704{
705 skb_release_head_state(skb);
706 if (likely(skb->head))
707 skb_release_data(skb);
708}
709
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717
718
719void __kfree_skb(struct sk_buff *skb)
720{
721 skb_release_all(skb);
722 kfree_skbmem(skb);
723}
724EXPORT_SYMBOL(__kfree_skb);
725
726
727
728
729
730
731
732
733void kfree_skb(struct sk_buff *skb)
734{
735 if (unlikely(!skb))
736 return;
737 if (likely(atomic_read(&skb->users) == 1))
738 smp_rmb();
739 else if (likely(!atomic_dec_and_test(&skb->users)))
740 return;
741 trace_kfree_skb(skb, __builtin_return_address(0));
742 __kfree_skb(skb);
743}
744EXPORT_SYMBOL(kfree_skb);
745
746void kfree_skb_list(struct sk_buff *segs)
747{
748 while (segs) {
749 struct sk_buff *next = segs->next;
750
751 kfree_skb(segs);
752 segs = next;
753 }
754}
755EXPORT_SYMBOL(kfree_skb_list);
756
757
758
759
760
761
762
763
764void skb_tx_error(struct sk_buff *skb)
765{
766 if (skb_shinfo(skb)->tx_flags & SKBTX_DEV_ZEROCOPY) {
767 struct ubuf_info *uarg;
768
769 uarg = skb_shinfo(skb)->destructor_arg;
770 if (uarg->callback)
771 uarg->callback(uarg, false);
772 skb_shinfo(skb)->tx_flags &= ~SKBTX_DEV_ZEROCOPY;
773 }
774}
775EXPORT_SYMBOL(skb_tx_error);
776
777
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781
782
783
784
785void consume_skb(struct sk_buff *skb)
786{
787 if (unlikely(!skb))
788 return;
789 if (likely(atomic_read(&skb->users) == 1))
790 smp_rmb();
791 else if (likely(!atomic_dec_and_test(&skb->users)))
792 return;
793 trace_consume_skb(skb);
794 __kfree_skb(skb);
795}
796EXPORT_SYMBOL(consume_skb);
797
798
799#define CHECK_SKB_FIELD(field) \
800 BUILD_BUG_ON(offsetof(struct sk_buff, field) < \
801 offsetof(struct sk_buff, headers_start)); \
802 BUILD_BUG_ON(offsetof(struct sk_buff, field) > \
803 offsetof(struct sk_buff, headers_end)); \
804
805static void __copy_skb_header(struct sk_buff *new, const struct sk_buff *old)
806{
807 new->tstamp = old->tstamp;
808
809 new->dev = old->dev;
810 memcpy(new->cb, old->cb, sizeof(old->cb));
811 skb_dst_copy(new, old);
812#ifdef CONFIG_XFRM
813 new->sp = secpath_get(old->sp);
814#endif
815 __nf_copy(new, old, false);
816
817
818
819
820 new->queue_mapping = old->queue_mapping;
821
822 memcpy(&new->headers_start, &old->headers_start,
823 offsetof(struct sk_buff, headers_end) -
824 offsetof(struct sk_buff, headers_start));
825 CHECK_SKB_FIELD(protocol);
826 CHECK_SKB_FIELD(csum);
827 CHECK_SKB_FIELD(hash);
828 CHECK_SKB_FIELD(priority);
829 CHECK_SKB_FIELD(skb_iif);
830 CHECK_SKB_FIELD(vlan_proto);
831 CHECK_SKB_FIELD(vlan_tci);
832 CHECK_SKB_FIELD(transport_header);
833 CHECK_SKB_FIELD(network_header);
834 CHECK_SKB_FIELD(mac_header);
835 CHECK_SKB_FIELD(inner_protocol);
836 CHECK_SKB_FIELD(inner_transport_header);
837 CHECK_SKB_FIELD(inner_network_header);
838 CHECK_SKB_FIELD(inner_mac_header);
839 CHECK_SKB_FIELD(mark);
840#ifdef CONFIG_NETWORK_SECMARK
841 CHECK_SKB_FIELD(secmark);
842#endif
843#ifdef CONFIG_NET_RX_BUSY_POLL
844 CHECK_SKB_FIELD(napi_id);
845#endif
846#ifdef CONFIG_XPS
847 CHECK_SKB_FIELD(sender_cpu);
848#endif
849#ifdef CONFIG_NET_SCHED
850 CHECK_SKB_FIELD(tc_index);
851#ifdef CONFIG_NET_CLS_ACT
852 CHECK_SKB_FIELD(tc_verd);
853#endif
854#endif
855
856}
857
858
859
860
861
862static struct sk_buff *__skb_clone(struct sk_buff *n, struct sk_buff *skb)
863{
864#define C(x) n->x = skb->x
865
866 n->next = n->prev = NULL;
867 n->sk = NULL;
868 __copy_skb_header(n, skb);
869
870 C(len);
871 C(data_len);
872 C(mac_len);
873 n->hdr_len = skb->nohdr ? skb_headroom(skb) : skb->hdr_len;
874 n->cloned = 1;
875 n->nohdr = 0;
876 n->destructor = NULL;
877 C(tail);
878 C(end);
879 C(head);
880 C(head_frag);
881 C(data);
882 C(truesize);
883 atomic_set(&n->users, 1);
884
885 atomic_inc(&(skb_shinfo(skb)->dataref));
886 skb->cloned = 1;
887
888 return n;
889#undef C
890}
891
892
893
894
895
896
897
898
899
900
901
902struct sk_buff *skb_morph(struct sk_buff *dst, struct sk_buff *src)
903{
904 skb_release_all(dst);
905 return __skb_clone(dst, src);
906}
907EXPORT_SYMBOL_GPL(skb_morph);
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924int skb_copy_ubufs(struct sk_buff *skb, gfp_t gfp_mask)
925{
926 int i;
927 int num_frags = skb_shinfo(skb)->nr_frags;
928 struct page *page, *head = NULL;
929 struct ubuf_info *uarg = skb_shinfo(skb)->destructor_arg;
930
931 for (i = 0; i < num_frags; i++) {
932 u8 *vaddr;
933 skb_frag_t *f = &skb_shinfo(skb)->frags[i];
934
935 page = alloc_page(gfp_mask);
936 if (!page) {
937 while (head) {
938 struct page *next = (struct page *)page_private(head);
939 put_page(head);
940 head = next;
941 }
942 return -ENOMEM;
943 }
944 vaddr = kmap_atomic(skb_frag_page(f));
945 memcpy(page_address(page),
946 vaddr + f->page_offset, skb_frag_size(f));
947 kunmap_atomic(vaddr);
948 set_page_private(page, (unsigned long)head);
949 head = page;
950 }
951
952
953 for (i = 0; i < num_frags; i++)
954 skb_frag_unref(skb, i);
955
956 uarg->callback(uarg, false);
957
958
959 for (i = num_frags - 1; i >= 0; i--) {
960 __skb_fill_page_desc(skb, i, head, 0,
961 skb_shinfo(skb)->frags[i].size);
962 head = (struct page *)page_private(head);
963 }
964
965 skb_shinfo(skb)->tx_flags &= ~SKBTX_DEV_ZEROCOPY;
966 return 0;
967}
968EXPORT_SYMBOL_GPL(skb_copy_ubufs);
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984struct sk_buff *skb_clone(struct sk_buff *skb, gfp_t gfp_mask)
985{
986 struct sk_buff_fclones *fclones = container_of(skb,
987 struct sk_buff_fclones,
988 skb1);
989 struct sk_buff *n;
990
991 if (skb_orphan_frags(skb, gfp_mask))
992 return NULL;
993
994 if (skb->fclone == SKB_FCLONE_ORIG &&
995 atomic_read(&fclones->fclone_ref) == 1) {
996 n = &fclones->skb2;
997 atomic_set(&fclones->fclone_ref, 2);
998 } else {
999 if (skb_pfmemalloc(skb))
1000 gfp_mask |= __GFP_MEMALLOC;
1001
1002 n = kmem_cache_alloc(skbuff_head_cache, gfp_mask);
1003 if (!n)
1004 return NULL;
1005
1006 kmemcheck_annotate_bitfield(n, flags1);
1007 n->fclone = SKB_FCLONE_UNAVAILABLE;
1008 }
1009
1010 return __skb_clone(n, skb);
1011}
1012EXPORT_SYMBOL(skb_clone);
1013
1014static void skb_headers_offset_update(struct sk_buff *skb, int off)
1015{
1016
1017 if (skb->ip_summed == CHECKSUM_PARTIAL)
1018 skb->csum_start += off;
1019
1020 skb->transport_header += off;
1021 skb->network_header += off;
1022 if (skb_mac_header_was_set(skb))
1023 skb->mac_header += off;
1024 skb->inner_transport_header += off;
1025 skb->inner_network_header += off;
1026 skb->inner_mac_header += off;
1027}
1028
1029static void copy_skb_header(struct sk_buff *new, const struct sk_buff *old)
1030{
1031 __copy_skb_header(new, old);
1032
1033 skb_shinfo(new)->gso_size = skb_shinfo(old)->gso_size;
1034 skb_shinfo(new)->gso_segs = skb_shinfo(old)->gso_segs;
1035 skb_shinfo(new)->gso_type = skb_shinfo(old)->gso_type;
1036}
1037
1038static inline int skb_alloc_rx_flag(const struct sk_buff *skb)
1039{
1040 if (skb_pfmemalloc(skb))
1041 return SKB_ALLOC_RX;
1042 return 0;
1043}
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062struct sk_buff *skb_copy(const struct sk_buff *skb, gfp_t gfp_mask)
1063{
1064 int headerlen = skb_headroom(skb);
1065 unsigned int size = skb_end_offset(skb) + skb->data_len;
1066 struct sk_buff *n = __alloc_skb(size, gfp_mask,
1067 skb_alloc_rx_flag(skb), NUMA_NO_NODE);
1068
1069 if (!n)
1070 return NULL;
1071
1072
1073 skb_reserve(n, headerlen);
1074
1075 skb_put(n, skb->len);
1076
1077 if (skb_copy_bits(skb, -headerlen, n->head, headerlen + skb->len))
1078 BUG();
1079
1080 copy_skb_header(n, skb);
1081 return n;
1082}
1083EXPORT_SYMBOL(skb_copy);
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102struct sk_buff *__pskb_copy_fclone(struct sk_buff *skb, int headroom,
1103 gfp_t gfp_mask, bool fclone)
1104{
1105 unsigned int size = skb_headlen(skb) + headroom;
1106 int flags = skb_alloc_rx_flag(skb) | (fclone ? SKB_ALLOC_FCLONE : 0);
1107 struct sk_buff *n = __alloc_skb(size, gfp_mask, flags, NUMA_NO_NODE);
1108
1109 if (!n)
1110 goto out;
1111
1112
1113 skb_reserve(n, headroom);
1114
1115 skb_put(n, skb_headlen(skb));
1116
1117 skb_copy_from_linear_data(skb, n->data, n->len);
1118
1119 n->truesize += skb->data_len;
1120 n->data_len = skb->data_len;
1121 n->len = skb->len;
1122
1123 if (skb_shinfo(skb)->nr_frags) {
1124 int i;
1125
1126 if (skb_orphan_frags(skb, gfp_mask)) {
1127 kfree_skb(n);
1128 n = NULL;
1129 goto out;
1130 }
1131 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
1132 skb_shinfo(n)->frags[i] = skb_shinfo(skb)->frags[i];
1133 skb_frag_ref(skb, i);
1134 }
1135 skb_shinfo(n)->nr_frags = i;
1136 }
1137
1138 if (skb_has_frag_list(skb)) {
1139 skb_shinfo(n)->frag_list = skb_shinfo(skb)->frag_list;
1140 skb_clone_fraglist(n);
1141 }
1142
1143 copy_skb_header(n, skb);
1144out:
1145 return n;
1146}
1147EXPORT_SYMBOL(__pskb_copy_fclone);
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165int pskb_expand_head(struct sk_buff *skb, int nhead, int ntail,
1166 gfp_t gfp_mask)
1167{
1168 int i;
1169 u8 *data;
1170 int size = nhead + skb_end_offset(skb) + ntail;
1171 long off;
1172
1173 BUG_ON(nhead < 0);
1174
1175 if (skb_shared(skb))
1176 BUG();
1177
1178 size = SKB_DATA_ALIGN(size);
1179
1180 if (skb_pfmemalloc(skb))
1181 gfp_mask |= __GFP_MEMALLOC;
1182 data = kmalloc_reserve(size + SKB_DATA_ALIGN(sizeof(struct skb_shared_info)),
1183 gfp_mask, NUMA_NO_NODE, NULL);
1184 if (!data)
1185 goto nodata;
1186 size = SKB_WITH_OVERHEAD(ksize(data));
1187
1188
1189
1190
1191 memcpy(data + nhead, skb->head, skb_tail_pointer(skb) - skb->head);
1192
1193 memcpy((struct skb_shared_info *)(data + size),
1194 skb_shinfo(skb),
1195 offsetof(struct skb_shared_info, frags[skb_shinfo(skb)->nr_frags]));
1196
1197
1198
1199
1200
1201
1202 if (skb_cloned(skb)) {
1203
1204 if (skb_orphan_frags(skb, gfp_mask))
1205 goto nofrags;
1206 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
1207 skb_frag_ref(skb, i);
1208
1209 if (skb_has_frag_list(skb))
1210 skb_clone_fraglist(skb);
1211
1212 skb_release_data(skb);
1213 } else {
1214 skb_free_head(skb);
1215 }
1216 off = (data + nhead) - skb->head;
1217
1218 skb->head = data;
1219 skb->head_frag = 0;
1220 skb->data += off;
1221#ifdef NET_SKBUFF_DATA_USES_OFFSET
1222 skb->end = size;
1223 off = nhead;
1224#else
1225 skb->end = skb->head + size;
1226#endif
1227 skb->tail += off;
1228 skb_headers_offset_update(skb, nhead);
1229 skb->cloned = 0;
1230 skb->hdr_len = 0;
1231 skb->nohdr = 0;
1232 atomic_set(&skb_shinfo(skb)->dataref, 1);
1233 return 0;
1234
1235nofrags:
1236 kfree(data);
1237nodata:
1238 return -ENOMEM;
1239}
1240EXPORT_SYMBOL(pskb_expand_head);
1241
1242
1243
1244struct sk_buff *skb_realloc_headroom(struct sk_buff *skb, unsigned int headroom)
1245{
1246 struct sk_buff *skb2;
1247 int delta = headroom - skb_headroom(skb);
1248
1249 if (delta <= 0)
1250 skb2 = pskb_copy(skb, GFP_ATOMIC);
1251 else {
1252 skb2 = skb_clone(skb, GFP_ATOMIC);
1253 if (skb2 && pskb_expand_head(skb2, SKB_DATA_ALIGN(delta), 0,
1254 GFP_ATOMIC)) {
1255 kfree_skb(skb2);
1256 skb2 = NULL;
1257 }
1258 }
1259 return skb2;
1260}
1261EXPORT_SYMBOL(skb_realloc_headroom);
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281struct sk_buff *skb_copy_expand(const struct sk_buff *skb,
1282 int newheadroom, int newtailroom,
1283 gfp_t gfp_mask)
1284{
1285
1286
1287
1288 struct sk_buff *n = __alloc_skb(newheadroom + skb->len + newtailroom,
1289 gfp_mask, skb_alloc_rx_flag(skb),
1290 NUMA_NO_NODE);
1291 int oldheadroom = skb_headroom(skb);
1292 int head_copy_len, head_copy_off;
1293
1294 if (!n)
1295 return NULL;
1296
1297 skb_reserve(n, newheadroom);
1298
1299
1300 skb_put(n, skb->len);
1301
1302 head_copy_len = oldheadroom;
1303 head_copy_off = 0;
1304 if (newheadroom <= head_copy_len)
1305 head_copy_len = newheadroom;
1306 else
1307 head_copy_off = newheadroom - head_copy_len;
1308
1309
1310 if (skb_copy_bits(skb, -head_copy_len, n->head + head_copy_off,
1311 skb->len + head_copy_len))
1312 BUG();
1313
1314 copy_skb_header(n, skb);
1315
1316 skb_headers_offset_update(n, newheadroom - oldheadroom);
1317
1318 return n;
1319}
1320EXPORT_SYMBOL(skb_copy_expand);
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334int skb_pad(struct sk_buff *skb, int pad)
1335{
1336 int err;
1337 int ntail;
1338
1339
1340 if (!skb_cloned(skb) && skb_tailroom(skb) >= pad) {
1341 memset(skb->data+skb->len, 0, pad);
1342 return 0;
1343 }
1344
1345 ntail = skb->data_len + pad - (skb->end - skb->tail);
1346 if (likely(skb_cloned(skb) || ntail > 0)) {
1347 err = pskb_expand_head(skb, 0, ntail, GFP_ATOMIC);
1348 if (unlikely(err))
1349 goto free_skb;
1350 }
1351
1352
1353
1354
1355 err = skb_linearize(skb);
1356 if (unlikely(err))
1357 goto free_skb;
1358
1359 memset(skb->data + skb->len, 0, pad);
1360 return 0;
1361
1362free_skb:
1363 kfree_skb(skb);
1364 return err;
1365}
1366EXPORT_SYMBOL(skb_pad);
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381unsigned char *pskb_put(struct sk_buff *skb, struct sk_buff *tail, int len)
1382{
1383 if (tail != skb) {
1384 skb->data_len += len;
1385 skb->len += len;
1386 }
1387 return skb_put(tail, len);
1388}
1389EXPORT_SYMBOL_GPL(pskb_put);
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400unsigned char *skb_put(struct sk_buff *skb, unsigned int len)
1401{
1402 unsigned char *tmp = skb_tail_pointer(skb);
1403 SKB_LINEAR_ASSERT(skb);
1404 skb->tail += len;
1405 skb->len += len;
1406 if (unlikely(skb->tail > skb->end))
1407 skb_over_panic(skb, len, __builtin_return_address(0));
1408 return tmp;
1409}
1410EXPORT_SYMBOL(skb_put);
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421unsigned char *skb_push(struct sk_buff *skb, unsigned int len)
1422{
1423 skb->data -= len;
1424 skb->len += len;
1425 if (unlikely(skb->data<skb->head))
1426 skb_under_panic(skb, len, __builtin_return_address(0));
1427 return skb->data;
1428}
1429EXPORT_SYMBOL(skb_push);
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441unsigned char *skb_pull(struct sk_buff *skb, unsigned int len)
1442{
1443 return skb_pull_inline(skb, len);
1444}
1445EXPORT_SYMBOL(skb_pull);
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456void skb_trim(struct sk_buff *skb, unsigned int len)
1457{
1458 if (skb->len > len)
1459 __skb_trim(skb, len);
1460}
1461EXPORT_SYMBOL(skb_trim);
1462
1463
1464
1465
1466int ___pskb_trim(struct sk_buff *skb, unsigned int len)
1467{
1468 struct sk_buff **fragp;
1469 struct sk_buff *frag;
1470 int offset = skb_headlen(skb);
1471 int nfrags = skb_shinfo(skb)->nr_frags;
1472 int i;
1473 int err;
1474
1475 if (skb_cloned(skb) &&
1476 unlikely((err = pskb_expand_head(skb, 0, 0, GFP_ATOMIC))))
1477 return err;
1478
1479 i = 0;
1480 if (offset >= len)
1481 goto drop_pages;
1482
1483 for (; i < nfrags; i++) {
1484 int end = offset + skb_frag_size(&skb_shinfo(skb)->frags[i]);
1485
1486 if (end < len) {
1487 offset = end;
1488 continue;
1489 }
1490
1491 skb_frag_size_set(&skb_shinfo(skb)->frags[i++], len - offset);
1492
1493drop_pages:
1494 skb_shinfo(skb)->nr_frags = i;
1495
1496 for (; i < nfrags; i++)
1497 skb_frag_unref(skb, i);
1498
1499 if (skb_has_frag_list(skb))
1500 skb_drop_fraglist(skb);
1501 goto done;
1502 }
1503
1504 for (fragp = &skb_shinfo(skb)->frag_list; (frag = *fragp);
1505 fragp = &frag->next) {
1506 int end = offset + frag->len;
1507
1508 if (skb_shared(frag)) {
1509 struct sk_buff *nfrag;
1510
1511 nfrag = skb_clone(frag, GFP_ATOMIC);
1512 if (unlikely(!nfrag))
1513 return -ENOMEM;
1514
1515 nfrag->next = frag->next;
1516 consume_skb(frag);
1517 frag = nfrag;
1518 *fragp = frag;
1519 }
1520
1521 if (end < len) {
1522 offset = end;
1523 continue;
1524 }
1525
1526 if (end > len &&
1527 unlikely((err = pskb_trim(frag, len - offset))))
1528 return err;
1529
1530 if (frag->next)
1531 skb_drop_list(&frag->next);
1532 break;
1533 }
1534
1535done:
1536 if (len > skb_headlen(skb)) {
1537 skb->data_len -= skb->len - len;
1538 skb->len = len;
1539 } else {
1540 skb->len = len;
1541 skb->data_len = 0;
1542 skb_set_tail_pointer(skb, len);
1543 }
1544
1545 return 0;
1546}
1547EXPORT_SYMBOL(___pskb_trim);
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574unsigned char *__pskb_pull_tail(struct sk_buff *skb, int delta)
1575{
1576
1577
1578
1579
1580 int i, k, eat = (skb->tail + delta) - skb->end;
1581
1582 if (eat > 0 || skb_cloned(skb)) {
1583 if (pskb_expand_head(skb, 0, eat > 0 ? eat + 128 : 0,
1584 GFP_ATOMIC))
1585 return NULL;
1586 }
1587
1588 if (skb_copy_bits(skb, skb_headlen(skb), skb_tail_pointer(skb), delta))
1589 BUG();
1590
1591
1592
1593
1594 if (!skb_has_frag_list(skb))
1595 goto pull_pages;
1596
1597
1598 eat = delta;
1599 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
1600 int size = skb_frag_size(&skb_shinfo(skb)->frags[i]);
1601
1602 if (size >= eat)
1603 goto pull_pages;
1604 eat -= size;
1605 }
1606
1607
1608
1609
1610
1611
1612
1613
1614 if (eat) {
1615 struct sk_buff *list = skb_shinfo(skb)->frag_list;
1616 struct sk_buff *clone = NULL;
1617 struct sk_buff *insp = NULL;
1618
1619 do {
1620 BUG_ON(!list);
1621
1622 if (list->len <= eat) {
1623
1624 eat -= list->len;
1625 list = list->next;
1626 insp = list;
1627 } else {
1628
1629
1630 if (skb_shared(list)) {
1631
1632 clone = skb_clone(list, GFP_ATOMIC);
1633 if (!clone)
1634 return NULL;
1635 insp = list->next;
1636 list = clone;
1637 } else {
1638
1639
1640 insp = list;
1641 }
1642 if (!pskb_pull(list, eat)) {
1643 kfree_skb(clone);
1644 return NULL;
1645 }
1646 break;
1647 }
1648 } while (eat);
1649
1650
1651 while ((list = skb_shinfo(skb)->frag_list) != insp) {
1652 skb_shinfo(skb)->frag_list = list->next;
1653 kfree_skb(list);
1654 }
1655
1656 if (clone) {
1657 clone->next = list;
1658 skb_shinfo(skb)->frag_list = clone;
1659 }
1660 }
1661
1662
1663pull_pages:
1664 eat = delta;
1665 k = 0;
1666 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
1667 int size = skb_frag_size(&skb_shinfo(skb)->frags[i]);
1668
1669 if (size <= eat) {
1670 skb_frag_unref(skb, i);
1671 eat -= size;
1672 } else {
1673 skb_shinfo(skb)->frags[k] = skb_shinfo(skb)->frags[i];
1674 if (eat) {
1675 skb_shinfo(skb)->frags[k].page_offset += eat;
1676 skb_frag_size_sub(&skb_shinfo(skb)->frags[k], eat);
1677 eat = 0;
1678 }
1679 k++;
1680 }
1681 }
1682 skb_shinfo(skb)->nr_frags = k;
1683
1684 skb->tail += delta;
1685 skb->data_len -= delta;
1686
1687 return skb_tail_pointer(skb);
1688}
1689EXPORT_SYMBOL(__pskb_pull_tail);
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706int skb_copy_bits(const struct sk_buff *skb, int offset, void *to, int len)
1707{
1708 int start = skb_headlen(skb);
1709 struct sk_buff *frag_iter;
1710 int i, copy;
1711
1712 if (offset > (int)skb->len - len)
1713 goto fault;
1714
1715
1716 if ((copy = start - offset) > 0) {
1717 if (copy > len)
1718 copy = len;
1719 skb_copy_from_linear_data_offset(skb, offset, to, copy);
1720 if ((len -= copy) == 0)
1721 return 0;
1722 offset += copy;
1723 to += copy;
1724 }
1725
1726 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
1727 int end;
1728 skb_frag_t *f = &skb_shinfo(skb)->frags[i];
1729
1730 WARN_ON(start > offset + len);
1731
1732 end = start + skb_frag_size(f);
1733 if ((copy = end - offset) > 0) {
1734 u8 *vaddr;
1735
1736 if (copy > len)
1737 copy = len;
1738
1739 vaddr = kmap_atomic(skb_frag_page(f));
1740 memcpy(to,
1741 vaddr + f->page_offset + offset - start,
1742 copy);
1743 kunmap_atomic(vaddr);
1744
1745 if ((len -= copy) == 0)
1746 return 0;
1747 offset += copy;
1748 to += copy;
1749 }
1750 start = end;
1751 }
1752
1753 skb_walk_frags(skb, frag_iter) {
1754 int end;
1755
1756 WARN_ON(start > offset + len);
1757
1758 end = start + frag_iter->len;
1759 if ((copy = end - offset) > 0) {
1760 if (copy > len)
1761 copy = len;
1762 if (skb_copy_bits(frag_iter, offset - start, to, copy))
1763 goto fault;
1764 if ((len -= copy) == 0)
1765 return 0;
1766 offset += copy;
1767 to += copy;
1768 }
1769 start = end;
1770 }
1771
1772 if (!len)
1773 return 0;
1774
1775fault:
1776 return -EFAULT;
1777}
1778EXPORT_SYMBOL(skb_copy_bits);
1779
1780
1781
1782
1783
1784static void sock_spd_release(struct splice_pipe_desc *spd, unsigned int i)
1785{
1786 put_page(spd->pages[i]);
1787}
1788
1789static struct page *linear_to_page(struct page *page, unsigned int *len,
1790 unsigned int *offset,
1791 struct sock *sk)
1792{
1793 struct page_frag *pfrag = sk_page_frag(sk);
1794
1795 if (!sk_page_frag_refill(sk, pfrag))
1796 return NULL;
1797
1798 *len = min_t(unsigned int, *len, pfrag->size - pfrag->offset);
1799
1800 memcpy(page_address(pfrag->page) + pfrag->offset,
1801 page_address(page) + *offset, *len);
1802 *offset = pfrag->offset;
1803 pfrag->offset += *len;
1804
1805 return pfrag->page;
1806}
1807
1808static bool spd_can_coalesce(const struct splice_pipe_desc *spd,
1809 struct page *page,
1810 unsigned int offset)
1811{
1812 return spd->nr_pages &&
1813 spd->pages[spd->nr_pages - 1] == page &&
1814 (spd->partial[spd->nr_pages - 1].offset +
1815 spd->partial[spd->nr_pages - 1].len == offset);
1816}
1817
1818
1819
1820
1821static bool spd_fill_page(struct splice_pipe_desc *spd,
1822 struct pipe_inode_info *pipe, struct page *page,
1823 unsigned int *len, unsigned int offset,
1824 bool linear,
1825 struct sock *sk)
1826{
1827 if (unlikely(spd->nr_pages == MAX_SKB_FRAGS))
1828 return true;
1829
1830 if (linear) {
1831 page = linear_to_page(page, len, &offset, sk);
1832 if (!page)
1833 return true;
1834 }
1835 if (spd_can_coalesce(spd, page, offset)) {
1836 spd->partial[spd->nr_pages - 1].len += *len;
1837 return false;
1838 }
1839 get_page(page);
1840 spd->pages[spd->nr_pages] = page;
1841 spd->partial[spd->nr_pages].len = *len;
1842 spd->partial[spd->nr_pages].offset = offset;
1843 spd->nr_pages++;
1844
1845 return false;
1846}
1847
1848static bool __splice_segment(struct page *page, unsigned int poff,
1849 unsigned int plen, unsigned int *off,
1850 unsigned int *len,
1851 struct splice_pipe_desc *spd, bool linear,
1852 struct sock *sk,
1853 struct pipe_inode_info *pipe)
1854{
1855 if (!*len)
1856 return true;
1857
1858
1859 if (*off >= plen) {
1860 *off -= plen;
1861 return false;
1862 }
1863
1864
1865 poff += *off;
1866 plen -= *off;
1867 *off = 0;
1868
1869 do {
1870 unsigned int flen = min(*len, plen);
1871
1872 if (spd_fill_page(spd, pipe, page, &flen, poff,
1873 linear, sk))
1874 return true;
1875 poff += flen;
1876 plen -= flen;
1877 *len -= flen;
1878 } while (*len && plen);
1879
1880 return false;
1881}
1882
1883
1884
1885
1886
1887static bool __skb_splice_bits(struct sk_buff *skb, struct pipe_inode_info *pipe,
1888 unsigned int *offset, unsigned int *len,
1889 struct splice_pipe_desc *spd, struct sock *sk)
1890{
1891 int seg;
1892
1893
1894
1895
1896
1897
1898 if (__splice_segment(virt_to_page(skb->data),
1899 (unsigned long) skb->data & (PAGE_SIZE - 1),
1900 skb_headlen(skb),
1901 offset, len, spd,
1902 skb_head_is_locked(skb),
1903 sk, pipe))
1904 return true;
1905
1906
1907
1908
1909 for (seg = 0; seg < skb_shinfo(skb)->nr_frags; seg++) {
1910 const skb_frag_t *f = &skb_shinfo(skb)->frags[seg];
1911
1912 if (__splice_segment(skb_frag_page(f),
1913 f->page_offset, skb_frag_size(f),
1914 offset, len, spd, false, sk, pipe))
1915 return true;
1916 }
1917
1918 return false;
1919}
1920
1921
1922
1923
1924
1925
1926
1927int skb_splice_bits(struct sk_buff *skb, unsigned int offset,
1928 struct pipe_inode_info *pipe, unsigned int tlen,
1929 unsigned int flags)
1930{
1931 struct partial_page partial[MAX_SKB_FRAGS];
1932 struct page *pages[MAX_SKB_FRAGS];
1933 struct splice_pipe_desc spd = {
1934 .pages = pages,
1935 .partial = partial,
1936 .nr_pages_max = MAX_SKB_FRAGS,
1937 .flags = flags,
1938 .ops = &nosteal_pipe_buf_ops,
1939 .spd_release = sock_spd_release,
1940 };
1941 struct sk_buff *frag_iter;
1942 struct sock *sk = skb->sk;
1943 int ret = 0;
1944
1945
1946
1947
1948
1949 if (__skb_splice_bits(skb, pipe, &offset, &tlen, &spd, sk))
1950 goto done;
1951 else if (!tlen)
1952 goto done;
1953
1954
1955
1956
1957 skb_walk_frags(skb, frag_iter) {
1958 if (!tlen)
1959 break;
1960 if (__skb_splice_bits(frag_iter, pipe, &offset, &tlen, &spd, sk))
1961 break;
1962 }
1963
1964done:
1965 if (spd.nr_pages) {
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975 release_sock(sk);
1976 ret = splice_to_pipe(pipe, &spd);
1977 lock_sock(sk);
1978 }
1979
1980 return ret;
1981}
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995int skb_store_bits(struct sk_buff *skb, int offset, const void *from, int len)
1996{
1997 int start = skb_headlen(skb);
1998 struct sk_buff *frag_iter;
1999 int i, copy;
2000
2001 if (offset > (int)skb->len - len)
2002 goto fault;
2003
2004 if ((copy = start - offset) > 0) {
2005 if (copy > len)
2006 copy = len;
2007 skb_copy_to_linear_data_offset(skb, offset, from, copy);
2008 if ((len -= copy) == 0)
2009 return 0;
2010 offset += copy;
2011 from += copy;
2012 }
2013
2014 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
2015 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
2016 int end;
2017
2018 WARN_ON(start > offset + len);
2019
2020 end = start + skb_frag_size(frag);
2021 if ((copy = end - offset) > 0) {
2022 u8 *vaddr;
2023
2024 if (copy > len)
2025 copy = len;
2026
2027 vaddr = kmap_atomic(skb_frag_page(frag));
2028 memcpy(vaddr + frag->page_offset + offset - start,
2029 from, copy);
2030 kunmap_atomic(vaddr);
2031
2032 if ((len -= copy) == 0)
2033 return 0;
2034 offset += copy;
2035 from += copy;
2036 }
2037 start = end;
2038 }
2039
2040 skb_walk_frags(skb, frag_iter) {
2041 int end;
2042
2043 WARN_ON(start > offset + len);
2044
2045 end = start + frag_iter->len;
2046 if ((copy = end - offset) > 0) {
2047 if (copy > len)
2048 copy = len;
2049 if (skb_store_bits(frag_iter, offset - start,
2050 from, copy))
2051 goto fault;
2052 if ((len -= copy) == 0)
2053 return 0;
2054 offset += copy;
2055 from += copy;
2056 }
2057 start = end;
2058 }
2059 if (!len)
2060 return 0;
2061
2062fault:
2063 return -EFAULT;
2064}
2065EXPORT_SYMBOL(skb_store_bits);
2066
2067
2068__wsum __skb_checksum(const struct sk_buff *skb, int offset, int len,
2069 __wsum csum, const struct skb_checksum_ops *ops)
2070{
2071 int start = skb_headlen(skb);
2072 int i, copy = start - offset;
2073 struct sk_buff *frag_iter;
2074 int pos = 0;
2075
2076
2077 if (copy > 0) {
2078 if (copy > len)
2079 copy = len;
2080 csum = ops->update(skb->data + offset, copy, csum);
2081 if ((len -= copy) == 0)
2082 return csum;
2083 offset += copy;
2084 pos = copy;
2085 }
2086
2087 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
2088 int end;
2089 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
2090
2091 WARN_ON(start > offset + len);
2092
2093 end = start + skb_frag_size(frag);
2094 if ((copy = end - offset) > 0) {
2095 __wsum csum2;
2096 u8 *vaddr;
2097
2098 if (copy > len)
2099 copy = len;
2100 vaddr = kmap_atomic(skb_frag_page(frag));
2101 csum2 = ops->update(vaddr + frag->page_offset +
2102 offset - start, copy, 0);
2103 kunmap_atomic(vaddr);
2104 csum = ops->combine(csum, csum2, pos, copy);
2105 if (!(len -= copy))
2106 return csum;
2107 offset += copy;
2108 pos += copy;
2109 }
2110 start = end;
2111 }
2112
2113 skb_walk_frags(skb, frag_iter) {
2114 int end;
2115
2116 WARN_ON(start > offset + len);
2117
2118 end = start + frag_iter->len;
2119 if ((copy = end - offset) > 0) {
2120 __wsum csum2;
2121 if (copy > len)
2122 copy = len;
2123 csum2 = __skb_checksum(frag_iter, offset - start,
2124 copy, 0, ops);
2125 csum = ops->combine(csum, csum2, pos, copy);
2126 if ((len -= copy) == 0)
2127 return csum;
2128 offset += copy;
2129 pos += copy;
2130 }
2131 start = end;
2132 }
2133 BUG_ON(len);
2134
2135 return csum;
2136}
2137EXPORT_SYMBOL(__skb_checksum);
2138
2139__wsum skb_checksum(const struct sk_buff *skb, int offset,
2140 int len, __wsum csum)
2141{
2142 const struct skb_checksum_ops ops = {
2143 .update = csum_partial_ext,
2144 .combine = csum_block_add_ext,
2145 };
2146
2147 return __skb_checksum(skb, offset, len, csum, &ops);
2148}
2149EXPORT_SYMBOL(skb_checksum);
2150
2151
2152
2153__wsum skb_copy_and_csum_bits(const struct sk_buff *skb, int offset,
2154 u8 *to, int len, __wsum csum)
2155{
2156 int start = skb_headlen(skb);
2157 int i, copy = start - offset;
2158 struct sk_buff *frag_iter;
2159 int pos = 0;
2160
2161
2162 if (copy > 0) {
2163 if (copy > len)
2164 copy = len;
2165 csum = csum_partial_copy_nocheck(skb->data + offset, to,
2166 copy, csum);
2167 if ((len -= copy) == 0)
2168 return csum;
2169 offset += copy;
2170 to += copy;
2171 pos = copy;
2172 }
2173
2174 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
2175 int end;
2176
2177 WARN_ON(start > offset + len);
2178
2179 end = start + skb_frag_size(&skb_shinfo(skb)->frags[i]);
2180 if ((copy = end - offset) > 0) {
2181 __wsum csum2;
2182 u8 *vaddr;
2183 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
2184
2185 if (copy > len)
2186 copy = len;
2187 vaddr = kmap_atomic(skb_frag_page(frag));
2188 csum2 = csum_partial_copy_nocheck(vaddr +
2189 frag->page_offset +
2190 offset - start, to,
2191 copy, 0);
2192 kunmap_atomic(vaddr);
2193 csum = csum_block_add(csum, csum2, pos);
2194 if (!(len -= copy))
2195 return csum;
2196 offset += copy;
2197 to += copy;
2198 pos += copy;
2199 }
2200 start = end;
2201 }
2202
2203 skb_walk_frags(skb, frag_iter) {
2204 __wsum csum2;
2205 int end;
2206
2207 WARN_ON(start > offset + len);
2208
2209 end = start + frag_iter->len;
2210 if ((copy = end - offset) > 0) {
2211 if (copy > len)
2212 copy = len;
2213 csum2 = skb_copy_and_csum_bits(frag_iter,
2214 offset - start,
2215 to, copy, 0);
2216 csum = csum_block_add(csum, csum2, pos);
2217 if ((len -= copy) == 0)
2218 return csum;
2219 offset += copy;
2220 to += copy;
2221 pos += copy;
2222 }
2223 start = end;
2224 }
2225 BUG_ON(len);
2226 return csum;
2227}
2228EXPORT_SYMBOL(skb_copy_and_csum_bits);
2229
2230
2231
2232
2233
2234
2235
2236
2237unsigned int
2238skb_zerocopy_headlen(const struct sk_buff *from)
2239{
2240 unsigned int hlen = 0;
2241
2242 if (!from->head_frag ||
2243 skb_headlen(from) < L1_CACHE_BYTES ||
2244 skb_shinfo(from)->nr_frags >= MAX_SKB_FRAGS)
2245 hlen = skb_headlen(from);
2246
2247 if (skb_has_frag_list(from))
2248 hlen = from->len;
2249
2250 return hlen;
2251}
2252EXPORT_SYMBOL_GPL(skb_zerocopy_headlen);
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272int
2273skb_zerocopy(struct sk_buff *to, struct sk_buff *from, int len, int hlen)
2274{
2275 int i, j = 0;
2276 int plen = 0;
2277 int ret;
2278 struct page *page;
2279 unsigned int offset;
2280
2281 BUG_ON(!from->head_frag && !hlen);
2282
2283
2284 if (len <= skb_tailroom(to))
2285 return skb_copy_bits(from, 0, skb_put(to, len), len);
2286
2287 if (hlen) {
2288 ret = skb_copy_bits(from, 0, skb_put(to, hlen), hlen);
2289 if (unlikely(ret))
2290 return ret;
2291 len -= hlen;
2292 } else {
2293 plen = min_t(int, skb_headlen(from), len);
2294 if (plen) {
2295 page = virt_to_head_page(from->head);
2296 offset = from->data - (unsigned char *)page_address(page);
2297 __skb_fill_page_desc(to, 0, page, offset, plen);
2298 get_page(page);
2299 j = 1;
2300 len -= plen;
2301 }
2302 }
2303
2304 to->truesize += len + plen;
2305 to->len += len + plen;
2306 to->data_len += len + plen;
2307
2308 if (unlikely(skb_orphan_frags(from, GFP_ATOMIC))) {
2309 skb_tx_error(from);
2310 return -ENOMEM;
2311 }
2312
2313 for (i = 0; i < skb_shinfo(from)->nr_frags; i++) {
2314 if (!len)
2315 break;
2316 skb_shinfo(to)->frags[j] = skb_shinfo(from)->frags[i];
2317 skb_shinfo(to)->frags[j].size = min_t(int, skb_shinfo(to)->frags[j].size, len);
2318 len -= skb_shinfo(to)->frags[j].size;
2319 skb_frag_ref(to, j);
2320 j++;
2321 }
2322 skb_shinfo(to)->nr_frags = j;
2323
2324 return 0;
2325}
2326EXPORT_SYMBOL_GPL(skb_zerocopy);
2327
2328void skb_copy_and_csum_dev(const struct sk_buff *skb, u8 *to)
2329{
2330 __wsum csum;
2331 long csstart;
2332
2333 if (skb->ip_summed == CHECKSUM_PARTIAL)
2334 csstart = skb_checksum_start_offset(skb);
2335 else
2336 csstart = skb_headlen(skb);
2337
2338 BUG_ON(csstart > skb_headlen(skb));
2339
2340 skb_copy_from_linear_data(skb, to, csstart);
2341
2342 csum = 0;
2343 if (csstart != skb->len)
2344 csum = skb_copy_and_csum_bits(skb, csstart, to + csstart,
2345 skb->len - csstart, 0);
2346
2347 if (skb->ip_summed == CHECKSUM_PARTIAL) {
2348 long csstuff = csstart + skb->csum_offset;
2349
2350 *((__sum16 *)(to + csstuff)) = csum_fold(csum);
2351 }
2352}
2353EXPORT_SYMBOL(skb_copy_and_csum_dev);
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364struct sk_buff *skb_dequeue(struct sk_buff_head *list)
2365{
2366 unsigned long flags;
2367 struct sk_buff *result;
2368
2369 spin_lock_irqsave(&list->lock, flags);
2370 result = __skb_dequeue(list);
2371 spin_unlock_irqrestore(&list->lock, flags);
2372 return result;
2373}
2374EXPORT_SYMBOL(skb_dequeue);
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384struct sk_buff *skb_dequeue_tail(struct sk_buff_head *list)
2385{
2386 unsigned long flags;
2387 struct sk_buff *result;
2388
2389 spin_lock_irqsave(&list->lock, flags);
2390 result = __skb_dequeue_tail(list);
2391 spin_unlock_irqrestore(&list->lock, flags);
2392 return result;
2393}
2394EXPORT_SYMBOL(skb_dequeue_tail);
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404void skb_queue_purge(struct sk_buff_head *list)
2405{
2406 struct sk_buff *skb;
2407 while ((skb = skb_dequeue(list)) != NULL)
2408 kfree_skb(skb);
2409}
2410EXPORT_SYMBOL(skb_queue_purge);
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423void skb_queue_head(struct sk_buff_head *list, struct sk_buff *newsk)
2424{
2425 unsigned long flags;
2426
2427 spin_lock_irqsave(&list->lock, flags);
2428 __skb_queue_head(list, newsk);
2429 spin_unlock_irqrestore(&list->lock, flags);
2430}
2431EXPORT_SYMBOL(skb_queue_head);
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444void skb_queue_tail(struct sk_buff_head *list, struct sk_buff *newsk)
2445{
2446 unsigned long flags;
2447
2448 spin_lock_irqsave(&list->lock, flags);
2449 __skb_queue_tail(list, newsk);
2450 spin_unlock_irqrestore(&list->lock, flags);
2451}
2452EXPORT_SYMBOL(skb_queue_tail);
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464void skb_unlink(struct sk_buff *skb, struct sk_buff_head *list)
2465{
2466 unsigned long flags;
2467
2468 spin_lock_irqsave(&list->lock, flags);
2469 __skb_unlink(skb, list);
2470 spin_unlock_irqrestore(&list->lock, flags);
2471}
2472EXPORT_SYMBOL(skb_unlink);
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484void skb_append(struct sk_buff *old, struct sk_buff *newsk, struct sk_buff_head *list)
2485{
2486 unsigned long flags;
2487
2488 spin_lock_irqsave(&list->lock, flags);
2489 __skb_queue_after(list, old, newsk);
2490 spin_unlock_irqrestore(&list->lock, flags);
2491}
2492EXPORT_SYMBOL(skb_append);
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506void skb_insert(struct sk_buff *old, struct sk_buff *newsk, struct sk_buff_head *list)
2507{
2508 unsigned long flags;
2509
2510 spin_lock_irqsave(&list->lock, flags);
2511 __skb_insert(newsk, old->prev, old, list);
2512 spin_unlock_irqrestore(&list->lock, flags);
2513}
2514EXPORT_SYMBOL(skb_insert);
2515
2516static inline void skb_split_inside_header(struct sk_buff *skb,
2517 struct sk_buff* skb1,
2518 const u32 len, const int pos)
2519{
2520 int i;
2521
2522 skb_copy_from_linear_data_offset(skb, len, skb_put(skb1, pos - len),
2523 pos - len);
2524
2525 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
2526 skb_shinfo(skb1)->frags[i] = skb_shinfo(skb)->frags[i];
2527
2528 skb_shinfo(skb1)->nr_frags = skb_shinfo(skb)->nr_frags;
2529 skb_shinfo(skb)->nr_frags = 0;
2530 skb1->data_len = skb->data_len;
2531 skb1->len += skb1->data_len;
2532 skb->data_len = 0;
2533 skb->len = len;
2534 skb_set_tail_pointer(skb, len);
2535}
2536
2537static inline void skb_split_no_header(struct sk_buff *skb,
2538 struct sk_buff* skb1,
2539 const u32 len, int pos)
2540{
2541 int i, k = 0;
2542 const int nfrags = skb_shinfo(skb)->nr_frags;
2543
2544 skb_shinfo(skb)->nr_frags = 0;
2545 skb1->len = skb1->data_len = skb->len - len;
2546 skb->len = len;
2547 skb->data_len = len - pos;
2548
2549 for (i = 0; i < nfrags; i++) {
2550 int size = skb_frag_size(&skb_shinfo(skb)->frags[i]);
2551
2552 if (pos + size > len) {
2553 skb_shinfo(skb1)->frags[k] = skb_shinfo(skb)->frags[i];
2554
2555 if (pos < len) {
2556
2557
2558
2559
2560
2561
2562
2563
2564 skb_frag_ref(skb, i);
2565 skb_shinfo(skb1)->frags[0].page_offset += len - pos;
2566 skb_frag_size_sub(&skb_shinfo(skb1)->frags[0], len - pos);
2567 skb_frag_size_set(&skb_shinfo(skb)->frags[i], len - pos);
2568 skb_shinfo(skb)->nr_frags++;
2569 }
2570 k++;
2571 } else
2572 skb_shinfo(skb)->nr_frags++;
2573 pos += size;
2574 }
2575 skb_shinfo(skb1)->nr_frags = k;
2576}
2577
2578
2579
2580
2581
2582
2583
2584void skb_split(struct sk_buff *skb, struct sk_buff *skb1, const u32 len)
2585{
2586 int pos = skb_headlen(skb);
2587
2588 skb_shinfo(skb1)->tx_flags = skb_shinfo(skb)->tx_flags & SKBTX_SHARED_FRAG;
2589 if (len < pos)
2590 skb_split_inside_header(skb, skb1, len, pos);
2591 else
2592 skb_split_no_header(skb, skb1, len, pos);
2593}
2594EXPORT_SYMBOL(skb_split);
2595
2596
2597
2598
2599
2600static int skb_prepare_for_shift(struct sk_buff *skb)
2601{
2602 return skb_cloned(skb) && pskb_expand_head(skb, 0, 0, GFP_ATOMIC);
2603}
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623int skb_shift(struct sk_buff *tgt, struct sk_buff *skb, int shiftlen)
2624{
2625 int from, to, merge, todo;
2626 struct skb_frag_struct *fragfrom, *fragto;
2627
2628 BUG_ON(shiftlen > skb->len);
2629 BUG_ON(skb_headlen(skb));
2630
2631 todo = shiftlen;
2632 from = 0;
2633 to = skb_shinfo(tgt)->nr_frags;
2634 fragfrom = &skb_shinfo(skb)->frags[from];
2635
2636
2637
2638
2639 if (!to ||
2640 !skb_can_coalesce(tgt, to, skb_frag_page(fragfrom),
2641 fragfrom->page_offset)) {
2642 merge = -1;
2643 } else {
2644 merge = to - 1;
2645
2646 todo -= skb_frag_size(fragfrom);
2647 if (todo < 0) {
2648 if (skb_prepare_for_shift(skb) ||
2649 skb_prepare_for_shift(tgt))
2650 return 0;
2651
2652
2653 fragfrom = &skb_shinfo(skb)->frags[from];
2654 fragto = &skb_shinfo(tgt)->frags[merge];
2655
2656 skb_frag_size_add(fragto, shiftlen);
2657 skb_frag_size_sub(fragfrom, shiftlen);
2658 fragfrom->page_offset += shiftlen;
2659
2660 goto onlymerged;
2661 }
2662
2663 from++;
2664 }
2665
2666
2667 if ((shiftlen == skb->len) &&
2668 (skb_shinfo(skb)->nr_frags - from) > (MAX_SKB_FRAGS - to))
2669 return 0;
2670
2671 if (skb_prepare_for_shift(skb) || skb_prepare_for_shift(tgt))
2672 return 0;
2673
2674 while ((todo > 0) && (from < skb_shinfo(skb)->nr_frags)) {
2675 if (to == MAX_SKB_FRAGS)
2676 return 0;
2677
2678 fragfrom = &skb_shinfo(skb)->frags[from];
2679 fragto = &skb_shinfo(tgt)->frags[to];
2680
2681 if (todo >= skb_frag_size(fragfrom)) {
2682 *fragto = *fragfrom;
2683 todo -= skb_frag_size(fragfrom);
2684 from++;
2685 to++;
2686
2687 } else {
2688 __skb_frag_ref(fragfrom);
2689 fragto->page = fragfrom->page;
2690 fragto->page_offset = fragfrom->page_offset;
2691 skb_frag_size_set(fragto, todo);
2692
2693 fragfrom->page_offset += todo;
2694 skb_frag_size_sub(fragfrom, todo);
2695 todo = 0;
2696
2697 to++;
2698 break;
2699 }
2700 }
2701
2702
2703 skb_shinfo(tgt)->nr_frags = to;
2704
2705 if (merge >= 0) {
2706 fragfrom = &skb_shinfo(skb)->frags[0];
2707 fragto = &skb_shinfo(tgt)->frags[merge];
2708
2709 skb_frag_size_add(fragto, skb_frag_size(fragfrom));
2710 __skb_frag_unref(fragfrom);
2711 }
2712
2713
2714 to = 0;
2715 while (from < skb_shinfo(skb)->nr_frags)
2716 skb_shinfo(skb)->frags[to++] = skb_shinfo(skb)->frags[from++];
2717 skb_shinfo(skb)->nr_frags = to;
2718
2719 BUG_ON(todo > 0 && !skb_shinfo(skb)->nr_frags);
2720
2721onlymerged:
2722
2723
2724
2725 tgt->ip_summed = CHECKSUM_PARTIAL;
2726 skb->ip_summed = CHECKSUM_PARTIAL;
2727
2728
2729 skb->len -= shiftlen;
2730 skb->data_len -= shiftlen;
2731 skb->truesize -= shiftlen;
2732 tgt->len += shiftlen;
2733 tgt->data_len += shiftlen;
2734 tgt->truesize += shiftlen;
2735
2736 return shiftlen;
2737}
2738
2739
2740
2741
2742
2743
2744
2745
2746
2747
2748
2749void skb_prepare_seq_read(struct sk_buff *skb, unsigned int from,
2750 unsigned int to, struct skb_seq_state *st)
2751{
2752 st->lower_offset = from;
2753 st->upper_offset = to;
2754 st->root_skb = st->cur_skb = skb;
2755 st->frag_idx = st->stepped_offset = 0;
2756 st->frag_data = NULL;
2757}
2758EXPORT_SYMBOL(skb_prepare_seq_read);
2759
2760
2761
2762
2763
2764
2765
2766
2767
2768
2769
2770
2771
2772
2773
2774
2775
2776
2777
2778
2779
2780
2781
2782
2783
2784
2785unsigned int skb_seq_read(unsigned int consumed, const u8 **data,
2786 struct skb_seq_state *st)
2787{
2788 unsigned int block_limit, abs_offset = consumed + st->lower_offset;
2789 skb_frag_t *frag;
2790
2791 if (unlikely(abs_offset >= st->upper_offset)) {
2792 if (st->frag_data) {
2793 kunmap_atomic(st->frag_data);
2794 st->frag_data = NULL;
2795 }
2796 return 0;
2797 }
2798
2799next_skb:
2800 block_limit = skb_headlen(st->cur_skb) + st->stepped_offset;
2801
2802 if (abs_offset < block_limit && !st->frag_data) {
2803 *data = st->cur_skb->data + (abs_offset - st->stepped_offset);
2804 return block_limit - abs_offset;
2805 }
2806
2807 if (st->frag_idx == 0 && !st->frag_data)
2808 st->stepped_offset += skb_headlen(st->cur_skb);
2809
2810 while (st->frag_idx < skb_shinfo(st->cur_skb)->nr_frags) {
2811 frag = &skb_shinfo(st->cur_skb)->frags[st->frag_idx];
2812 block_limit = skb_frag_size(frag) + st->stepped_offset;
2813
2814 if (abs_offset < block_limit) {
2815 if (!st->frag_data)
2816 st->frag_data = kmap_atomic(skb_frag_page(frag));
2817
2818 *data = (u8 *) st->frag_data + frag->page_offset +
2819 (abs_offset - st->stepped_offset);
2820
2821 return block_limit - abs_offset;
2822 }
2823
2824 if (st->frag_data) {
2825 kunmap_atomic(st->frag_data);
2826 st->frag_data = NULL;
2827 }
2828
2829 st->frag_idx++;
2830 st->stepped_offset += skb_frag_size(frag);
2831 }
2832
2833 if (st->frag_data) {
2834 kunmap_atomic(st->frag_data);
2835 st->frag_data = NULL;
2836 }
2837
2838 if (st->root_skb == st->cur_skb && skb_has_frag_list(st->root_skb)) {
2839 st->cur_skb = skb_shinfo(st->root_skb)->frag_list;
2840 st->frag_idx = 0;
2841 goto next_skb;
2842 } else if (st->cur_skb->next) {
2843 st->cur_skb = st->cur_skb->next;
2844 st->frag_idx = 0;
2845 goto next_skb;
2846 }
2847
2848 return 0;
2849}
2850EXPORT_SYMBOL(skb_seq_read);
2851
2852
2853
2854
2855
2856
2857
2858
2859void skb_abort_seq_read(struct skb_seq_state *st)
2860{
2861 if (st->frag_data)
2862 kunmap_atomic(st->frag_data);
2863}
2864EXPORT_SYMBOL(skb_abort_seq_read);
2865
2866#define TS_SKB_CB(state) ((struct skb_seq_state *) &((state)->cb))
2867
2868static unsigned int skb_ts_get_next_block(unsigned int offset, const u8 **text,
2869 struct ts_config *conf,
2870 struct ts_state *state)
2871{
2872 return skb_seq_read(offset, text, TS_SKB_CB(state));
2873}
2874
2875static void skb_ts_finish(struct ts_config *conf, struct ts_state *state)
2876{
2877 skb_abort_seq_read(TS_SKB_CB(state));
2878}
2879
2880
2881
2882
2883
2884
2885
2886
2887
2888
2889
2890
2891
2892unsigned int skb_find_text(struct sk_buff *skb, unsigned int from,
2893 unsigned int to, struct ts_config *config)
2894{
2895 struct ts_state state;
2896 unsigned int ret;
2897
2898 config->get_next_block = skb_ts_get_next_block;
2899 config->finish = skb_ts_finish;
2900
2901 skb_prepare_seq_read(skb, from, to, TS_SKB_CB(&state));
2902
2903 ret = textsearch_find(config, &state);
2904 return (ret <= to - from ? ret : UINT_MAX);
2905}
2906EXPORT_SYMBOL(skb_find_text);
2907
2908
2909
2910
2911
2912
2913
2914
2915
2916
2917
2918
2919int skb_append_datato_frags(struct sock *sk, struct sk_buff *skb,
2920 int (*getfrag)(void *from, char *to, int offset,
2921 int len, int odd, struct sk_buff *skb),
2922 void *from, int length)
2923{
2924 int frg_cnt = skb_shinfo(skb)->nr_frags;
2925 int copy;
2926 int offset = 0;
2927 int ret;
2928 struct page_frag *pfrag = ¤t->task_frag;
2929
2930 do {
2931
2932 if (frg_cnt >= MAX_SKB_FRAGS)
2933 return -EMSGSIZE;
2934
2935 if (!sk_page_frag_refill(sk, pfrag))
2936 return -ENOMEM;
2937
2938
2939 copy = min_t(int, length, pfrag->size - pfrag->offset);
2940
2941 ret = getfrag(from, page_address(pfrag->page) + pfrag->offset,
2942 offset, copy, 0, skb);
2943 if (ret < 0)
2944 return -EFAULT;
2945
2946
2947 skb_fill_page_desc(skb, frg_cnt, pfrag->page, pfrag->offset,
2948 copy);
2949 frg_cnt++;
2950 pfrag->offset += copy;
2951 get_page(pfrag->page);
2952
2953 skb->truesize += copy;
2954 atomic_add(copy, &sk->sk_wmem_alloc);
2955 skb->len += copy;
2956 skb->data_len += copy;
2957 offset += copy;
2958 length -= copy;
2959
2960 } while (length > 0);
2961
2962 return 0;
2963}
2964EXPORT_SYMBOL(skb_append_datato_frags);
2965
2966
2967
2968
2969
2970
2971
2972
2973
2974
2975
2976
2977unsigned char *skb_pull_rcsum(struct sk_buff *skb, unsigned int len)
2978{
2979 BUG_ON(len > skb->len);
2980 skb->len -= len;
2981 BUG_ON(skb->len < skb->data_len);
2982 skb_postpull_rcsum(skb, skb->data, len);
2983 return skb->data += len;
2984}
2985EXPORT_SYMBOL_GPL(skb_pull_rcsum);
2986
2987
2988
2989
2990
2991
2992
2993
2994
2995
2996struct sk_buff *skb_segment(struct sk_buff *head_skb,
2997 netdev_features_t features)
2998{
2999 struct sk_buff *segs = NULL;
3000 struct sk_buff *tail = NULL;
3001 struct sk_buff *list_skb = skb_shinfo(head_skb)->frag_list;
3002 skb_frag_t *frag = skb_shinfo(head_skb)->frags;
3003 unsigned int mss = skb_shinfo(head_skb)->gso_size;
3004 unsigned int doffset = head_skb->data - skb_mac_header(head_skb);
3005 struct sk_buff *frag_skb = head_skb;
3006 unsigned int offset = doffset;
3007 unsigned int tnl_hlen = skb_tnl_header_len(head_skb);
3008 unsigned int headroom;
3009 unsigned int len;
3010 __be16 proto;
3011 bool csum;
3012 int sg = !!(features & NETIF_F_SG);
3013 int nfrags = skb_shinfo(head_skb)->nr_frags;
3014 int err = -ENOMEM;
3015 int i = 0;
3016 int pos;
3017 int dummy;
3018
3019 __skb_push(head_skb, doffset);
3020 proto = skb_network_protocol(head_skb, &dummy);
3021 if (unlikely(!proto))
3022 return ERR_PTR(-EINVAL);
3023
3024 csum = !head_skb->encap_hdr_csum &&
3025 !!can_checksum_protocol(features, proto);
3026
3027 headroom = skb_headroom(head_skb);
3028 pos = skb_headlen(head_skb);
3029
3030 do {
3031 struct sk_buff *nskb;
3032 skb_frag_t *nskb_frag;
3033 int hsize;
3034 int size;
3035
3036 len = head_skb->len - offset;
3037 if (len > mss)
3038 len = mss;
3039
3040 hsize = skb_headlen(head_skb) - offset;
3041 if (hsize < 0)
3042 hsize = 0;
3043 if (hsize > len || !sg)
3044 hsize = len;
3045
3046 if (!hsize && i >= nfrags && skb_headlen(list_skb) &&
3047 (skb_headlen(list_skb) == len || sg)) {
3048 BUG_ON(skb_headlen(list_skb) > len);
3049
3050 i = 0;
3051 nfrags = skb_shinfo(list_skb)->nr_frags;
3052 frag = skb_shinfo(list_skb)->frags;
3053 frag_skb = list_skb;
3054 pos += skb_headlen(list_skb);
3055
3056 while (pos < offset + len) {
3057 BUG_ON(i >= nfrags);
3058
3059 size = skb_frag_size(frag);
3060 if (pos + size > offset + len)
3061 break;
3062
3063 i++;
3064 pos += size;
3065 frag++;
3066 }
3067
3068 nskb = skb_clone(list_skb, GFP_ATOMIC);
3069 list_skb = list_skb->next;
3070
3071 if (unlikely(!nskb))
3072 goto err;
3073
3074 if (unlikely(pskb_trim(nskb, len))) {
3075 kfree_skb(nskb);
3076 goto err;
3077 }
3078
3079 hsize = skb_end_offset(nskb);
3080 if (skb_cow_head(nskb, doffset + headroom)) {
3081 kfree_skb(nskb);
3082 goto err;
3083 }
3084
3085 nskb->truesize += skb_end_offset(nskb) - hsize;
3086 skb_release_head_state(nskb);
3087 __skb_push(nskb, doffset);
3088 } else {
3089 nskb = __alloc_skb(hsize + doffset + headroom,
3090 GFP_ATOMIC, skb_alloc_rx_flag(head_skb),
3091 NUMA_NO_NODE);
3092
3093 if (unlikely(!nskb))
3094 goto err;
3095
3096 skb_reserve(nskb, headroom);
3097 __skb_put(nskb, doffset);
3098 }
3099
3100 if (segs)
3101 tail->next = nskb;
3102 else
3103 segs = nskb;
3104 tail = nskb;
3105
3106 __copy_skb_header(nskb, head_skb);
3107
3108 skb_headers_offset_update(nskb, skb_headroom(nskb) - headroom);
3109 skb_reset_mac_len(nskb);
3110
3111 skb_copy_from_linear_data_offset(head_skb, -tnl_hlen,
3112 nskb->data - tnl_hlen,
3113 doffset + tnl_hlen);
3114
3115 if (nskb->len == len + doffset)
3116 goto perform_csum_check;
3117
3118 if (!sg && !nskb->remcsum_offload) {
3119 nskb->ip_summed = CHECKSUM_NONE;
3120 nskb->csum = skb_copy_and_csum_bits(head_skb, offset,
3121 skb_put(nskb, len),
3122 len, 0);
3123 SKB_GSO_CB(nskb)->csum_start =
3124 skb_headroom(nskb) + doffset;
3125 continue;
3126 }
3127
3128 nskb_frag = skb_shinfo(nskb)->frags;
3129
3130 skb_copy_from_linear_data_offset(head_skb, offset,
3131 skb_put(nskb, hsize), hsize);
3132
3133 skb_shinfo(nskb)->tx_flags = skb_shinfo(head_skb)->tx_flags &
3134 SKBTX_SHARED_FRAG;
3135
3136 while (pos < offset + len) {
3137 if (i >= nfrags) {
3138 BUG_ON(skb_headlen(list_skb));
3139
3140 i = 0;
3141 nfrags = skb_shinfo(list_skb)->nr_frags;
3142 frag = skb_shinfo(list_skb)->frags;
3143 frag_skb = list_skb;
3144
3145 BUG_ON(!nfrags);
3146
3147 list_skb = list_skb->next;
3148 }
3149
3150 if (unlikely(skb_shinfo(nskb)->nr_frags >=
3151 MAX_SKB_FRAGS)) {
3152 net_warn_ratelimited(
3153 "skb_segment: too many frags: %u %u\n",
3154 pos, mss);
3155 goto err;
3156 }
3157
3158 if (unlikely(skb_orphan_frags(frag_skb, GFP_ATOMIC)))
3159 goto err;
3160
3161 *nskb_frag = *frag;
3162 __skb_frag_ref(nskb_frag);
3163 size = skb_frag_size(nskb_frag);
3164
3165 if (pos < offset) {
3166 nskb_frag->page_offset += offset - pos;
3167 skb_frag_size_sub(nskb_frag, offset - pos);
3168 }
3169
3170 skb_shinfo(nskb)->nr_frags++;
3171
3172 if (pos + size <= offset + len) {
3173 i++;
3174 frag++;
3175 pos += size;
3176 } else {
3177 skb_frag_size_sub(nskb_frag, pos + size - (offset + len));
3178 goto skip_fraglist;
3179 }
3180
3181 nskb_frag++;
3182 }
3183
3184skip_fraglist:
3185 nskb->data_len = len - hsize;
3186 nskb->len += nskb->data_len;
3187 nskb->truesize += nskb->data_len;
3188
3189perform_csum_check:
3190 if (!csum && !nskb->remcsum_offload) {
3191 nskb->csum = skb_checksum(nskb, doffset,
3192 nskb->len - doffset, 0);
3193 nskb->ip_summed = CHECKSUM_NONE;
3194 SKB_GSO_CB(nskb)->csum_start =
3195 skb_headroom(nskb) + doffset;
3196 }
3197 } while ((offset += len) < head_skb->len);
3198
3199
3200
3201
3202
3203 segs->prev = tail;
3204
3205
3206
3207
3208
3209 if (head_skb->destructor == sock_wfree) {
3210 swap(tail->truesize, head_skb->truesize);
3211 swap(tail->destructor, head_skb->destructor);
3212 swap(tail->sk, head_skb->sk);
3213 }
3214 return segs;
3215
3216err:
3217 kfree_skb_list(segs);
3218 return ERR_PTR(err);
3219}
3220EXPORT_SYMBOL_GPL(skb_segment);
3221
3222int skb_gro_receive(struct sk_buff **head, struct sk_buff *skb)
3223{
3224 struct skb_shared_info *pinfo, *skbinfo = skb_shinfo(skb);
3225 unsigned int offset = skb_gro_offset(skb);
3226 unsigned int headlen = skb_headlen(skb);
3227 unsigned int len = skb_gro_len(skb);
3228 struct sk_buff *lp, *p = *head;
3229 unsigned int delta_truesize;
3230
3231 if (unlikely(p->len + len >= 65536))
3232 return -E2BIG;
3233
3234 lp = NAPI_GRO_CB(p)->last;
3235 pinfo = skb_shinfo(lp);
3236
3237 if (headlen <= offset) {
3238 skb_frag_t *frag;
3239 skb_frag_t *frag2;
3240 int i = skbinfo->nr_frags;
3241 int nr_frags = pinfo->nr_frags + i;
3242
3243 if (nr_frags > MAX_SKB_FRAGS)
3244 goto merge;
3245
3246 offset -= headlen;
3247 pinfo->nr_frags = nr_frags;
3248 skbinfo->nr_frags = 0;
3249
3250 frag = pinfo->frags + nr_frags;
3251 frag2 = skbinfo->frags + i;
3252 do {
3253 *--frag = *--frag2;
3254 } while (--i);
3255
3256 frag->page_offset += offset;
3257 skb_frag_size_sub(frag, offset);
3258
3259
3260 delta_truesize = skb->truesize -
3261 SKB_TRUESIZE(skb_end_offset(skb));
3262
3263 skb->truesize -= skb->data_len;
3264 skb->len -= skb->data_len;
3265 skb->data_len = 0;
3266
3267 NAPI_GRO_CB(skb)->free = NAPI_GRO_FREE;
3268 goto done;
3269 } else if (skb->head_frag) {
3270 int nr_frags = pinfo->nr_frags;
3271 skb_frag_t *frag = pinfo->frags + nr_frags;
3272 struct page *page = virt_to_head_page(skb->head);
3273 unsigned int first_size = headlen - offset;
3274 unsigned int first_offset;
3275
3276 if (nr_frags + 1 + skbinfo->nr_frags > MAX_SKB_FRAGS)
3277 goto merge;
3278
3279 first_offset = skb->data -
3280 (unsigned char *)page_address(page) +
3281 offset;
3282
3283 pinfo->nr_frags = nr_frags + 1 + skbinfo->nr_frags;
3284
3285 frag->page.p = page;
3286 frag->page_offset = first_offset;
3287 skb_frag_size_set(frag, first_size);
3288
3289 memcpy(frag + 1, skbinfo->frags, sizeof(*frag) * skbinfo->nr_frags);
3290
3291
3292 delta_truesize = skb->truesize - SKB_DATA_ALIGN(sizeof(struct sk_buff));
3293 NAPI_GRO_CB(skb)->free = NAPI_GRO_FREE_STOLEN_HEAD;
3294 goto done;
3295 }
3296
3297merge:
3298 delta_truesize = skb->truesize;
3299 if (offset > headlen) {
3300 unsigned int eat = offset - headlen;
3301
3302 skbinfo->frags[0].page_offset += eat;
3303 skb_frag_size_sub(&skbinfo->frags[0], eat);
3304 skb->data_len -= eat;
3305 skb->len -= eat;
3306 offset = headlen;
3307 }
3308
3309 __skb_pull(skb, offset);
3310
3311 if (NAPI_GRO_CB(p)->last == p)
3312 skb_shinfo(p)->frag_list = skb;
3313 else
3314 NAPI_GRO_CB(p)->last->next = skb;
3315 NAPI_GRO_CB(p)->last = skb;
3316 __skb_header_release(skb);
3317 lp = p;
3318
3319done:
3320 NAPI_GRO_CB(p)->count++;
3321 p->data_len += len;
3322 p->truesize += delta_truesize;
3323 p->len += len;
3324 if (lp != p) {
3325 lp->data_len += len;
3326 lp->truesize += delta_truesize;
3327 lp->len += len;
3328 }
3329 NAPI_GRO_CB(skb)->same_flow = 1;
3330 return 0;
3331}
3332
3333void __init skb_init(void)
3334{
3335 skbuff_head_cache = kmem_cache_create("skbuff_head_cache",
3336 sizeof(struct sk_buff),
3337 0,
3338 SLAB_HWCACHE_ALIGN|SLAB_PANIC,
3339 NULL);
3340 skbuff_fclone_cache = kmem_cache_create("skbuff_fclone_cache",
3341 sizeof(struct sk_buff_fclones),
3342 0,
3343 SLAB_HWCACHE_ALIGN|SLAB_PANIC,
3344 NULL);
3345}
3346
3347
3348
3349
3350
3351
3352
3353
3354
3355
3356
3357static int
3358__skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int len)
3359{
3360 int start = skb_headlen(skb);
3361 int i, copy = start - offset;
3362 struct sk_buff *frag_iter;
3363 int elt = 0;
3364
3365 if (copy > 0) {
3366 if (copy > len)
3367 copy = len;
3368 sg_set_buf(sg, skb->data + offset, copy);
3369 elt++;
3370 if ((len -= copy) == 0)
3371 return elt;
3372 offset += copy;
3373 }
3374
3375 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
3376 int end;
3377
3378 WARN_ON(start > offset + len);
3379
3380 end = start + skb_frag_size(&skb_shinfo(skb)->frags[i]);
3381 if ((copy = end - offset) > 0) {
3382 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
3383
3384 if (copy > len)
3385 copy = len;
3386 sg_set_page(&sg[elt], skb_frag_page(frag), copy,
3387 frag->page_offset+offset-start);
3388 elt++;
3389 if (!(len -= copy))
3390 return elt;
3391 offset += copy;
3392 }
3393 start = end;
3394 }
3395
3396 skb_walk_frags(skb, frag_iter) {
3397 int end;
3398
3399 WARN_ON(start > offset + len);
3400
3401 end = start + frag_iter->len;
3402 if ((copy = end - offset) > 0) {
3403 if (copy > len)
3404 copy = len;
3405 elt += __skb_to_sgvec(frag_iter, sg+elt, offset - start,
3406 copy);
3407 if ((len -= copy) == 0)
3408 return elt;
3409 offset += copy;
3410 }
3411 start = end;
3412 }
3413 BUG_ON(len);
3414 return elt;
3415}
3416
3417
3418
3419
3420
3421
3422
3423
3424
3425
3426
3427
3428
3429
3430
3431
3432
3433
3434
3435
3436int skb_to_sgvec_nomark(struct sk_buff *skb, struct scatterlist *sg,
3437 int offset, int len)
3438{
3439 return __skb_to_sgvec(skb, sg, offset, len);
3440}
3441EXPORT_SYMBOL_GPL(skb_to_sgvec_nomark);
3442
3443int skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int len)
3444{
3445 int nsg = __skb_to_sgvec(skb, sg, offset, len);
3446
3447 sg_mark_end(&sg[nsg - 1]);
3448
3449 return nsg;
3450}
3451EXPORT_SYMBOL_GPL(skb_to_sgvec);
3452
3453
3454
3455
3456
3457
3458
3459
3460
3461
3462
3463
3464
3465
3466
3467
3468
3469
3470int skb_cow_data(struct sk_buff *skb, int tailbits, struct sk_buff **trailer)
3471{
3472 int copyflag;
3473 int elt;
3474 struct sk_buff *skb1, **skb_p;
3475
3476
3477
3478
3479
3480 if ((skb_cloned(skb) || skb_shinfo(skb)->nr_frags) &&
3481 __pskb_pull_tail(skb, skb_pagelen(skb)-skb_headlen(skb)) == NULL)
3482 return -ENOMEM;
3483
3484
3485 if (!skb_has_frag_list(skb)) {
3486
3487
3488
3489
3490
3491 if (skb_tailroom(skb) < tailbits &&
3492 pskb_expand_head(skb, 0, tailbits-skb_tailroom(skb)+128, GFP_ATOMIC))
3493 return -ENOMEM;
3494
3495
3496 *trailer = skb;
3497 return 1;
3498 }
3499
3500
3501
3502 elt = 1;
3503 skb_p = &skb_shinfo(skb)->frag_list;
3504 copyflag = 0;
3505
3506 while ((skb1 = *skb_p) != NULL) {
3507 int ntail = 0;
3508
3509
3510
3511
3512
3513 if (skb_shared(skb1))
3514 copyflag = 1;
3515
3516
3517
3518 if (skb1->next == NULL && tailbits) {
3519 if (skb_shinfo(skb1)->nr_frags ||
3520 skb_has_frag_list(skb1) ||
3521 skb_tailroom(skb1) < tailbits)
3522 ntail = tailbits + 128;
3523 }
3524
3525 if (copyflag ||
3526 skb_cloned(skb1) ||
3527 ntail ||
3528 skb_shinfo(skb1)->nr_frags ||
3529 skb_has_frag_list(skb1)) {
3530 struct sk_buff *skb2;
3531
3532
3533 if (ntail == 0)
3534 skb2 = skb_copy(skb1, GFP_ATOMIC);
3535 else
3536 skb2 = skb_copy_expand(skb1,
3537 skb_headroom(skb1),
3538 ntail,
3539 GFP_ATOMIC);
3540 if (unlikely(skb2 == NULL))
3541 return -ENOMEM;
3542
3543 if (skb1->sk)
3544 skb_set_owner_w(skb2, skb1->sk);
3545
3546
3547
3548
3549 skb2->next = skb1->next;
3550 *skb_p = skb2;
3551 kfree_skb(skb1);
3552 skb1 = skb2;
3553 }
3554 elt++;
3555 *trailer = skb1;
3556 skb_p = &skb1->next;
3557 }
3558
3559 return elt;
3560}
3561EXPORT_SYMBOL_GPL(skb_cow_data);
3562
3563static void sock_rmem_free(struct sk_buff *skb)
3564{
3565 struct sock *sk = skb->sk;
3566
3567 atomic_sub(skb->truesize, &sk->sk_rmem_alloc);
3568}
3569
3570
3571
3572
3573int sock_queue_err_skb(struct sock *sk, struct sk_buff *skb)
3574{
3575 if (atomic_read(&sk->sk_rmem_alloc) + skb->truesize >=
3576 (unsigned int)sk->sk_rcvbuf)
3577 return -ENOMEM;
3578
3579 skb_orphan(skb);
3580 skb->sk = sk;
3581 skb->destructor = sock_rmem_free;
3582 atomic_add(skb->truesize, &sk->sk_rmem_alloc);
3583
3584
3585 skb_dst_force(skb);
3586
3587 skb_queue_tail(&sk->sk_error_queue, skb);
3588 if (!sock_flag(sk, SOCK_DEAD))
3589 sk->sk_data_ready(sk);
3590 return 0;
3591}
3592EXPORT_SYMBOL(sock_queue_err_skb);
3593
3594struct sk_buff *sock_dequeue_err_skb(struct sock *sk)
3595{
3596 struct sk_buff_head *q = &sk->sk_error_queue;
3597 struct sk_buff *skb, *skb_next;
3598 unsigned long flags;
3599 int err = 0;
3600
3601 spin_lock_irqsave(&q->lock, flags);
3602 skb = __skb_dequeue(q);
3603 if (skb && (skb_next = skb_peek(q)))
3604 err = SKB_EXT_ERR(skb_next)->ee.ee_errno;
3605 spin_unlock_irqrestore(&q->lock, flags);
3606
3607 sk->sk_err = err;
3608 if (err)
3609 sk->sk_error_report(sk);
3610
3611 return skb;
3612}
3613EXPORT_SYMBOL(sock_dequeue_err_skb);
3614
3615
3616
3617
3618
3619
3620
3621
3622
3623
3624
3625
3626
3627
3628struct sk_buff *skb_clone_sk(struct sk_buff *skb)
3629{
3630 struct sock *sk = skb->sk;
3631 struct sk_buff *clone;
3632
3633 if (!sk || !atomic_inc_not_zero(&sk->sk_refcnt))
3634 return NULL;
3635
3636 clone = skb_clone(skb, GFP_ATOMIC);
3637 if (!clone) {
3638 sock_put(sk);
3639 return NULL;
3640 }
3641
3642 clone->sk = sk;
3643 clone->destructor = sock_efree;
3644
3645 return clone;
3646}
3647EXPORT_SYMBOL(skb_clone_sk);
3648
3649static void __skb_complete_tx_timestamp(struct sk_buff *skb,
3650 struct sock *sk,
3651 int tstype)
3652{
3653 struct sock_exterr_skb *serr;
3654 int err;
3655
3656 serr = SKB_EXT_ERR(skb);
3657 memset(serr, 0, sizeof(*serr));
3658 serr->ee.ee_errno = ENOMSG;
3659 serr->ee.ee_origin = SO_EE_ORIGIN_TIMESTAMPING;
3660 serr->ee.ee_info = tstype;
3661 if (sk->sk_tsflags & SOF_TIMESTAMPING_OPT_ID) {
3662 serr->ee.ee_data = skb_shinfo(skb)->tskey;
3663 if (sk->sk_protocol == IPPROTO_TCP)
3664 serr->ee.ee_data -= sk->sk_tskey;
3665 }
3666
3667 err = sock_queue_err_skb(sk, skb);
3668
3669 if (err)
3670 kfree_skb(skb);
3671}
3672
3673static bool skb_may_tx_timestamp(struct sock *sk, bool tsonly)
3674{
3675 bool ret;
3676
3677 if (likely(sysctl_tstamp_allow_data || tsonly))
3678 return true;
3679
3680 read_lock_bh(&sk->sk_callback_lock);
3681 ret = sk->sk_socket && sk->sk_socket->file &&
3682 file_ns_capable(sk->sk_socket->file, &init_user_ns, CAP_NET_RAW);
3683 read_unlock_bh(&sk->sk_callback_lock);
3684 return ret;
3685}
3686
3687void skb_complete_tx_timestamp(struct sk_buff *skb,
3688 struct skb_shared_hwtstamps *hwtstamps)
3689{
3690 struct sock *sk = skb->sk;
3691
3692 if (!skb_may_tx_timestamp(sk, false))
3693 return;
3694
3695
3696 sock_hold(sk);
3697
3698 *skb_hwtstamps(skb) = *hwtstamps;
3699 __skb_complete_tx_timestamp(skb, sk, SCM_TSTAMP_SND);
3700
3701 sock_put(sk);
3702}
3703EXPORT_SYMBOL_GPL(skb_complete_tx_timestamp);
3704
3705void __skb_tstamp_tx(struct sk_buff *orig_skb,
3706 struct skb_shared_hwtstamps *hwtstamps,
3707 struct sock *sk, int tstype)
3708{
3709 struct sk_buff *skb;
3710 bool tsonly;
3711
3712 if (!sk)
3713 return;
3714
3715 tsonly = sk->sk_tsflags & SOF_TIMESTAMPING_OPT_TSONLY;
3716 if (!skb_may_tx_timestamp(sk, tsonly))
3717 return;
3718
3719 if (tsonly)
3720 skb = alloc_skb(0, GFP_ATOMIC);
3721 else
3722 skb = skb_clone(orig_skb, GFP_ATOMIC);
3723 if (!skb)
3724 return;
3725
3726 if (tsonly) {
3727 skb_shinfo(skb)->tx_flags = skb_shinfo(orig_skb)->tx_flags;
3728 skb_shinfo(skb)->tskey = skb_shinfo(orig_skb)->tskey;
3729 }
3730
3731 if (hwtstamps)
3732 *skb_hwtstamps(skb) = *hwtstamps;
3733 else
3734 skb->tstamp = ktime_get_real();
3735
3736 __skb_complete_tx_timestamp(skb, sk, tstype);
3737}
3738EXPORT_SYMBOL_GPL(__skb_tstamp_tx);
3739
3740void skb_tstamp_tx(struct sk_buff *orig_skb,
3741 struct skb_shared_hwtstamps *hwtstamps)
3742{
3743 return __skb_tstamp_tx(orig_skb, hwtstamps, orig_skb->sk,
3744 SCM_TSTAMP_SND);
3745}
3746EXPORT_SYMBOL_GPL(skb_tstamp_tx);
3747
3748void skb_complete_wifi_ack(struct sk_buff *skb, bool acked)
3749{
3750 struct sock *sk = skb->sk;
3751 struct sock_exterr_skb *serr;
3752 int err;
3753
3754 skb->wifi_acked_valid = 1;
3755 skb->wifi_acked = acked;
3756
3757 serr = SKB_EXT_ERR(skb);
3758 memset(serr, 0, sizeof(*serr));
3759 serr->ee.ee_errno = ENOMSG;
3760 serr->ee.ee_origin = SO_EE_ORIGIN_TXSTATUS;
3761
3762
3763 sock_hold(sk);
3764
3765 err = sock_queue_err_skb(sk, skb);
3766 if (err)
3767 kfree_skb(skb);
3768
3769 sock_put(sk);
3770}
3771EXPORT_SYMBOL_GPL(skb_complete_wifi_ack);
3772
3773
3774
3775
3776
3777
3778
3779
3780
3781
3782
3783
3784
3785bool skb_partial_csum_set(struct sk_buff *skb, u16 start, u16 off)
3786{
3787 if (unlikely(start > skb_headlen(skb)) ||
3788 unlikely((int)start + off > skb_headlen(skb) - 2)) {
3789 net_warn_ratelimited("bad partial csum: csum=%u/%u len=%u\n",
3790 start, off, skb_headlen(skb));
3791 return false;
3792 }
3793 skb->ip_summed = CHECKSUM_PARTIAL;
3794 skb->csum_start = skb_headroom(skb) + start;
3795 skb->csum_offset = off;
3796 skb_set_transport_header(skb, start);
3797 return true;
3798}
3799EXPORT_SYMBOL_GPL(skb_partial_csum_set);
3800
3801static int skb_maybe_pull_tail(struct sk_buff *skb, unsigned int len,
3802 unsigned int max)
3803{
3804 if (skb_headlen(skb) >= len)
3805 return 0;
3806
3807
3808
3809
3810 if (max > skb->len)
3811 max = skb->len;
3812
3813 if (__pskb_pull_tail(skb, max - skb_headlen(skb)) == NULL)
3814 return -ENOMEM;
3815
3816 if (skb_headlen(skb) < len)
3817 return -EPROTO;
3818
3819 return 0;
3820}
3821
3822#define MAX_TCP_HDR_LEN (15 * 4)
3823
3824static __sum16 *skb_checksum_setup_ip(struct sk_buff *skb,
3825 typeof(IPPROTO_IP) proto,
3826 unsigned int off)
3827{
3828 switch (proto) {
3829 int err;
3830
3831 case IPPROTO_TCP:
3832 err = skb_maybe_pull_tail(skb, off + sizeof(struct tcphdr),
3833 off + MAX_TCP_HDR_LEN);
3834 if (!err && !skb_partial_csum_set(skb, off,
3835 offsetof(struct tcphdr,
3836 check)))
3837 err = -EPROTO;
3838 return err ? ERR_PTR(err) : &tcp_hdr(skb)->check;
3839
3840 case IPPROTO_UDP:
3841 err = skb_maybe_pull_tail(skb, off + sizeof(struct udphdr),
3842 off + sizeof(struct udphdr));
3843 if (!err && !skb_partial_csum_set(skb, off,
3844 offsetof(struct udphdr,
3845 check)))
3846 err = -EPROTO;
3847 return err ? ERR_PTR(err) : &udp_hdr(skb)->check;
3848 }
3849
3850 return ERR_PTR(-EPROTO);
3851}
3852
3853
3854
3855
3856#define MAX_IP_HDR_LEN 128
3857
3858static int skb_checksum_setup_ipv4(struct sk_buff *skb, bool recalculate)
3859{
3860 unsigned int off;
3861 bool fragment;
3862 __sum16 *csum;
3863 int err;
3864
3865 fragment = false;
3866
3867 err = skb_maybe_pull_tail(skb,
3868 sizeof(struct iphdr),
3869 MAX_IP_HDR_LEN);
3870 if (err < 0)
3871 goto out;
3872
3873 if (ip_hdr(skb)->frag_off & htons(IP_OFFSET | IP_MF))
3874 fragment = true;
3875
3876 off = ip_hdrlen(skb);
3877
3878 err = -EPROTO;
3879
3880 if (fragment)
3881 goto out;
3882
3883 csum = skb_checksum_setup_ip(skb, ip_hdr(skb)->protocol, off);
3884 if (IS_ERR(csum))
3885 return PTR_ERR(csum);
3886
3887 if (recalculate)
3888 *csum = ~csum_tcpudp_magic(ip_hdr(skb)->saddr,
3889 ip_hdr(skb)->daddr,
3890 skb->len - off,
3891 ip_hdr(skb)->protocol, 0);
3892 err = 0;
3893
3894out:
3895 return err;
3896}
3897
3898
3899
3900
3901#define MAX_IPV6_HDR_LEN 256
3902
3903#define OPT_HDR(type, skb, off) \
3904 (type *)(skb_network_header(skb) + (off))
3905
3906static int skb_checksum_setup_ipv6(struct sk_buff *skb, bool recalculate)
3907{
3908 int err;
3909 u8 nexthdr;
3910 unsigned int off;
3911 unsigned int len;
3912 bool fragment;
3913 bool done;
3914 __sum16 *csum;
3915
3916 fragment = false;
3917 done = false;
3918
3919 off = sizeof(struct ipv6hdr);
3920
3921 err = skb_maybe_pull_tail(skb, off, MAX_IPV6_HDR_LEN);
3922 if (err < 0)
3923 goto out;
3924
3925 nexthdr = ipv6_hdr(skb)->nexthdr;
3926
3927 len = sizeof(struct ipv6hdr) + ntohs(ipv6_hdr(skb)->payload_len);
3928 while (off <= len && !done) {
3929 switch (nexthdr) {
3930 case IPPROTO_DSTOPTS:
3931 case IPPROTO_HOPOPTS:
3932 case IPPROTO_ROUTING: {
3933 struct ipv6_opt_hdr *hp;
3934
3935 err = skb_maybe_pull_tail(skb,
3936 off +
3937 sizeof(struct ipv6_opt_hdr),
3938 MAX_IPV6_HDR_LEN);
3939 if (err < 0)
3940 goto out;
3941
3942 hp = OPT_HDR(struct ipv6_opt_hdr, skb, off);
3943 nexthdr = hp->nexthdr;
3944 off += ipv6_optlen(hp);
3945 break;
3946 }
3947 case IPPROTO_AH: {
3948 struct ip_auth_hdr *hp;
3949
3950 err = skb_maybe_pull_tail(skb,
3951 off +
3952 sizeof(struct ip_auth_hdr),
3953 MAX_IPV6_HDR_LEN);
3954 if (err < 0)
3955 goto out;
3956
3957 hp = OPT_HDR(struct ip_auth_hdr, skb, off);
3958 nexthdr = hp->nexthdr;
3959 off += ipv6_authlen(hp);
3960 break;
3961 }
3962 case IPPROTO_FRAGMENT: {
3963 struct frag_hdr *hp;
3964
3965 err = skb_maybe_pull_tail(skb,
3966 off +
3967 sizeof(struct frag_hdr),
3968 MAX_IPV6_HDR_LEN);
3969 if (err < 0)
3970 goto out;
3971
3972 hp = OPT_HDR(struct frag_hdr, skb, off);
3973
3974 if (hp->frag_off & htons(IP6_OFFSET | IP6_MF))
3975 fragment = true;
3976
3977 nexthdr = hp->nexthdr;
3978 off += sizeof(struct frag_hdr);
3979 break;
3980 }
3981 default:
3982 done = true;
3983 break;
3984 }
3985 }
3986
3987 err = -EPROTO;
3988
3989 if (!done || fragment)
3990 goto out;
3991
3992 csum = skb_checksum_setup_ip(skb, nexthdr, off);
3993 if (IS_ERR(csum))
3994 return PTR_ERR(csum);
3995
3996 if (recalculate)
3997 *csum = ~csum_ipv6_magic(&ipv6_hdr(skb)->saddr,
3998 &ipv6_hdr(skb)->daddr,
3999 skb->len - off, nexthdr, 0);
4000 err = 0;
4001
4002out:
4003 return err;
4004}
4005
4006
4007
4008
4009
4010
4011int skb_checksum_setup(struct sk_buff *skb, bool recalculate)
4012{
4013 int err;
4014
4015 switch (skb->protocol) {
4016 case htons(ETH_P_IP):
4017 err = skb_checksum_setup_ipv4(skb, recalculate);
4018 break;
4019
4020 case htons(ETH_P_IPV6):
4021 err = skb_checksum_setup_ipv6(skb, recalculate);
4022 break;
4023
4024 default:
4025 err = -EPROTO;
4026 break;
4027 }
4028
4029 return err;
4030}
4031EXPORT_SYMBOL(skb_checksum_setup);
4032
4033void __skb_warn_lro_forwarding(const struct sk_buff *skb)
4034{
4035 net_warn_ratelimited("%s: received packets cannot be forwarded while LRO is enabled\n",
4036 skb->dev->name);
4037}
4038EXPORT_SYMBOL(__skb_warn_lro_forwarding);
4039
4040void kfree_skb_partial(struct sk_buff *skb, bool head_stolen)
4041{
4042 if (head_stolen) {
4043 skb_release_head_state(skb);
4044 kmem_cache_free(skbuff_head_cache, skb);
4045 } else {
4046 __kfree_skb(skb);
4047 }
4048}
4049EXPORT_SYMBOL(kfree_skb_partial);
4050
4051
4052
4053
4054
4055
4056
4057
4058bool skb_try_coalesce(struct sk_buff *to, struct sk_buff *from,
4059 bool *fragstolen, int *delta_truesize)
4060{
4061 int i, delta, len = from->len;
4062
4063 *fragstolen = false;
4064
4065 if (skb_cloned(to))
4066 return false;
4067
4068 if (len <= skb_tailroom(to)) {
4069 if (len)
4070 BUG_ON(skb_copy_bits(from, 0, skb_put(to, len), len));
4071 *delta_truesize = 0;
4072 return true;
4073 }
4074
4075 if (skb_has_frag_list(to) || skb_has_frag_list(from))
4076 return false;
4077
4078 if (skb_headlen(from) != 0) {
4079 struct page *page;
4080 unsigned int offset;
4081
4082 if (skb_shinfo(to)->nr_frags +
4083 skb_shinfo(from)->nr_frags >= MAX_SKB_FRAGS)
4084 return false;
4085
4086 if (skb_head_is_locked(from))
4087 return false;
4088
4089 delta = from->truesize - SKB_DATA_ALIGN(sizeof(struct sk_buff));
4090
4091 page = virt_to_head_page(from->head);
4092 offset = from->data - (unsigned char *)page_address(page);
4093
4094 skb_fill_page_desc(to, skb_shinfo(to)->nr_frags,
4095 page, offset, skb_headlen(from));
4096 *fragstolen = true;
4097 } else {
4098 if (skb_shinfo(to)->nr_frags +
4099 skb_shinfo(from)->nr_frags > MAX_SKB_FRAGS)
4100 return false;
4101
4102 delta = from->truesize - SKB_TRUESIZE(skb_end_offset(from));
4103 }
4104
4105 WARN_ON_ONCE(delta < len);
4106
4107 memcpy(skb_shinfo(to)->frags + skb_shinfo(to)->nr_frags,
4108 skb_shinfo(from)->frags,
4109 skb_shinfo(from)->nr_frags * sizeof(skb_frag_t));
4110 skb_shinfo(to)->nr_frags += skb_shinfo(from)->nr_frags;
4111
4112 if (!skb_cloned(from))
4113 skb_shinfo(from)->nr_frags = 0;
4114
4115
4116
4117
4118 for (i = 0; i < skb_shinfo(from)->nr_frags; i++)
4119 skb_frag_ref(from, i);
4120
4121 to->truesize += delta;
4122 to->len += len;
4123 to->data_len += len;
4124
4125 *delta_truesize = delta;
4126 return true;
4127}
4128EXPORT_SYMBOL(skb_try_coalesce);
4129
4130
4131
4132
4133
4134
4135
4136
4137
4138
4139
4140
4141
4142
4143void skb_scrub_packet(struct sk_buff *skb, bool xnet)
4144{
4145 skb->tstamp.tv64 = 0;
4146 skb->pkt_type = PACKET_HOST;
4147 skb->skb_iif = 0;
4148 skb->ignore_df = 0;
4149 skb_dst_drop(skb);
4150 skb_sender_cpu_clear(skb);
4151 secpath_reset(skb);
4152 nf_reset(skb);
4153 nf_reset_trace(skb);
4154
4155 if (!xnet)
4156 return;
4157
4158 skb_orphan(skb);
4159 skb->mark = 0;
4160}
4161EXPORT_SYMBOL_GPL(skb_scrub_packet);
4162
4163
4164
4165
4166
4167
4168
4169
4170
4171
4172
4173unsigned int skb_gso_transport_seglen(const struct sk_buff *skb)
4174{
4175 const struct skb_shared_info *shinfo = skb_shinfo(skb);
4176 unsigned int thlen = 0;
4177
4178 if (skb->encapsulation) {
4179 thlen = skb_inner_transport_header(skb) -
4180 skb_transport_header(skb);
4181
4182 if (likely(shinfo->gso_type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6)))
4183 thlen += inner_tcp_hdrlen(skb);
4184 } else if (likely(shinfo->gso_type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6))) {
4185 thlen = tcp_hdrlen(skb);
4186 }
4187
4188
4189
4190
4191 return thlen + shinfo->gso_size;
4192}
4193EXPORT_SYMBOL_GPL(skb_gso_transport_seglen);
4194
4195static struct sk_buff *skb_reorder_vlan_header(struct sk_buff *skb)
4196{
4197 if (skb_cow(skb, skb_headroom(skb)) < 0) {
4198 kfree_skb(skb);
4199 return NULL;
4200 }
4201
4202 memmove(skb->data - ETH_HLEN, skb->data - VLAN_ETH_HLEN, 2 * ETH_ALEN);
4203 skb->mac_header += VLAN_HLEN;
4204 return skb;
4205}
4206
4207struct sk_buff *skb_vlan_untag(struct sk_buff *skb)
4208{
4209 struct vlan_hdr *vhdr;
4210 u16 vlan_tci;
4211
4212 if (unlikely(skb_vlan_tag_present(skb))) {
4213
4214 return skb;
4215 }
4216
4217 skb = skb_share_check(skb, GFP_ATOMIC);
4218 if (unlikely(!skb))
4219 goto err_free;
4220
4221 if (unlikely(!pskb_may_pull(skb, VLAN_HLEN)))
4222 goto err_free;
4223
4224 vhdr = (struct vlan_hdr *)skb->data;
4225 vlan_tci = ntohs(vhdr->h_vlan_TCI);
4226 __vlan_hwaccel_put_tag(skb, skb->protocol, vlan_tci);
4227
4228 skb_pull_rcsum(skb, VLAN_HLEN);
4229 vlan_set_encap_proto(skb, vhdr);
4230
4231 skb = skb_reorder_vlan_header(skb);
4232 if (unlikely(!skb))
4233 goto err_free;
4234
4235 skb_reset_network_header(skb);
4236 skb_reset_transport_header(skb);
4237 skb_reset_mac_len(skb);
4238
4239 return skb;
4240
4241err_free:
4242 kfree_skb(skb);
4243 return NULL;
4244}
4245EXPORT_SYMBOL(skb_vlan_untag);
4246
4247int skb_ensure_writable(struct sk_buff *skb, int write_len)
4248{
4249 if (!pskb_may_pull(skb, write_len))
4250 return -ENOMEM;
4251
4252 if (!skb_cloned(skb) || skb_clone_writable(skb, write_len))
4253 return 0;
4254
4255 return pskb_expand_head(skb, 0, 0, GFP_ATOMIC);
4256}
4257EXPORT_SYMBOL(skb_ensure_writable);
4258
4259
4260static int __skb_vlan_pop(struct sk_buff *skb, u16 *vlan_tci)
4261{
4262 struct vlan_hdr *vhdr;
4263 unsigned int offset = skb->data - skb_mac_header(skb);
4264 int err;
4265
4266 __skb_push(skb, offset);
4267 err = skb_ensure_writable(skb, VLAN_ETH_HLEN);
4268 if (unlikely(err))
4269 goto pull;
4270
4271 skb_postpull_rcsum(skb, skb->data + (2 * ETH_ALEN), VLAN_HLEN);
4272
4273 vhdr = (struct vlan_hdr *)(skb->data + ETH_HLEN);
4274 *vlan_tci = ntohs(vhdr->h_vlan_TCI);
4275
4276 memmove(skb->data + VLAN_HLEN, skb->data, 2 * ETH_ALEN);
4277 __skb_pull(skb, VLAN_HLEN);
4278
4279 vlan_set_encap_proto(skb, vhdr);
4280 skb->mac_header += VLAN_HLEN;
4281
4282 if (skb_network_offset(skb) < ETH_HLEN)
4283 skb_set_network_header(skb, ETH_HLEN);
4284
4285 skb_reset_mac_len(skb);
4286pull:
4287 __skb_pull(skb, offset);
4288
4289 return err;
4290}
4291
4292int skb_vlan_pop(struct sk_buff *skb)
4293{
4294 u16 vlan_tci;
4295 __be16 vlan_proto;
4296 int err;
4297
4298 if (likely(skb_vlan_tag_present(skb))) {
4299 skb->vlan_tci = 0;
4300 } else {
4301 if (unlikely((skb->protocol != htons(ETH_P_8021Q) &&
4302 skb->protocol != htons(ETH_P_8021AD)) ||
4303 skb->len < VLAN_ETH_HLEN))
4304 return 0;
4305
4306 err = __skb_vlan_pop(skb, &vlan_tci);
4307 if (err)
4308 return err;
4309 }
4310
4311 if (likely((skb->protocol != htons(ETH_P_8021Q) &&
4312 skb->protocol != htons(ETH_P_8021AD)) ||
4313 skb->len < VLAN_ETH_HLEN))
4314 return 0;
4315
4316 vlan_proto = skb->protocol;
4317 err = __skb_vlan_pop(skb, &vlan_tci);
4318 if (unlikely(err))
4319 return err;
4320
4321 __vlan_hwaccel_put_tag(skb, vlan_proto, vlan_tci);
4322 return 0;
4323}
4324EXPORT_SYMBOL(skb_vlan_pop);
4325
4326int skb_vlan_push(struct sk_buff *skb, __be16 vlan_proto, u16 vlan_tci)
4327{
4328 if (skb_vlan_tag_present(skb)) {
4329 unsigned int offset = skb->data - skb_mac_header(skb);
4330 int err;
4331
4332
4333
4334
4335
4336 __skb_push(skb, offset);
4337 err = __vlan_insert_tag(skb, skb->vlan_proto,
4338 skb_vlan_tag_get(skb));
4339 if (err)
4340 return err;
4341 skb->protocol = skb->vlan_proto;
4342 skb->mac_len += VLAN_HLEN;
4343 __skb_pull(skb, offset);
4344
4345 if (skb->ip_summed == CHECKSUM_COMPLETE)
4346 skb->csum = csum_add(skb->csum, csum_partial(skb->data
4347 + (2 * ETH_ALEN), VLAN_HLEN, 0));
4348 }
4349 __vlan_hwaccel_put_tag(skb, vlan_proto, vlan_tci);
4350 return 0;
4351}
4352EXPORT_SYMBOL(skb_vlan_push);
4353
4354
4355
4356
4357
4358
4359
4360
4361
4362
4363
4364
4365struct sk_buff *alloc_skb_with_frags(unsigned long header_len,
4366 unsigned long data_len,
4367 int max_page_order,
4368 int *errcode,
4369 gfp_t gfp_mask)
4370{
4371 int npages = (data_len + (PAGE_SIZE - 1)) >> PAGE_SHIFT;
4372 unsigned long chunk;
4373 struct sk_buff *skb;
4374 struct page *page;
4375 gfp_t gfp_head;
4376 int i;
4377
4378 *errcode = -EMSGSIZE;
4379
4380
4381
4382 if (npages > MAX_SKB_FRAGS)
4383 return NULL;
4384
4385 gfp_head = gfp_mask;
4386 if (gfp_head & __GFP_WAIT)
4387 gfp_head |= __GFP_REPEAT;
4388
4389 *errcode = -ENOBUFS;
4390 skb = alloc_skb(header_len, gfp_head);
4391 if (!skb)
4392 return NULL;
4393
4394 skb->truesize += npages << PAGE_SHIFT;
4395
4396 for (i = 0; npages > 0; i++) {
4397 int order = max_page_order;
4398
4399 while (order) {
4400 if (npages >= 1 << order) {
4401 page = alloc_pages((gfp_mask & ~__GFP_WAIT) |
4402 __GFP_COMP |
4403 __GFP_NOWARN |
4404 __GFP_NORETRY,
4405 order);
4406 if (page)
4407 goto fill_page;
4408
4409 order = 1;
4410 max_page_order = 0;
4411 }
4412 order--;
4413 }
4414 page = alloc_page(gfp_mask);
4415 if (!page)
4416 goto failure;
4417fill_page:
4418 chunk = min_t(unsigned long, data_len,
4419 PAGE_SIZE << order);
4420 skb_fill_page_desc(skb, i, page, 0, chunk);
4421 data_len -= chunk;
4422 npages -= 1 << order;
4423 }
4424 return skb;
4425
4426failure:
4427 kfree_skb(skb);
4428 return NULL;
4429}
4430EXPORT_SYMBOL(alloc_skb_with_frags);
4431