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1 /*
2 * Definitions for the 'struct sk_buff' memory handlers.
3 *
4 * Authors:
5 * Alan Cox, <gw4pts@gw4pts.ampr.org>
6 * Florian La Roche, <rzsfl@rz.uni-sb.de>
7 *
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License
10 * as published by the Free Software Foundation; either version
11 * 2 of the License, or (at your option) any later version.
12 */
13
14 #ifndef _LINUX_SKBUFF_H
15 #define _LINUX_SKBUFF_H
16
17 #include <linux/kernel.h>
18 #include <linux/kmemcheck.h>
19 #include <linux/compiler.h>
20 #include <linux/time.h>
21 #include <linux/cache.h>
22
23 #include <asm/atomic.h>
24 #include <asm/types.h>
25 #include <linux/spinlock.h>
26 #include <linux/net.h>
27 #include <linux/textsearch.h>
28 #include <net/checksum.h>
29 #include <linux/rcupdate.h>
30 #include <linux/dmaengine.h>
31 #include <linux/hrtimer.h>
32
33 /* Don't change this without changing skb_csum_unnecessary! */
34 #define CHECKSUM_NONE 0
35 #define CHECKSUM_UNNECESSARY 1
36 #define CHECKSUM_COMPLETE 2
37 #define CHECKSUM_PARTIAL 3
38
39 #define SKB_DATA_ALIGN(X) (((X) + (SMP_CACHE_BYTES - 1)) & \
40 ~(SMP_CACHE_BYTES - 1))
41 #define SKB_WITH_OVERHEAD(X) \
42 ((X) - SKB_DATA_ALIGN(sizeof(struct skb_shared_info)))
43 #define SKB_MAX_ORDER(X, ORDER) \
44 SKB_WITH_OVERHEAD((PAGE_SIZE << (ORDER)) - (X))
45 #define SKB_MAX_HEAD(X) (SKB_MAX_ORDER((X), 0))
46 #define SKB_MAX_ALLOC (SKB_MAX_ORDER(0, 2))
47
48 /* A. Checksumming of received packets by device.
49 *
50 * NONE: device failed to checksum this packet.
51 * skb->csum is undefined.
52 *
53 * UNNECESSARY: device parsed packet and wouldbe verified checksum.
54 * skb->csum is undefined.
55 * It is bad option, but, unfortunately, many of vendors do this.
56 * Apparently with secret goal to sell you new device, when you
57 * will add new protocol to your host. F.e. IPv6. 8)
58 *
59 * COMPLETE: the most generic way. Device supplied checksum of _all_
60 * the packet as seen by netif_rx in skb->csum.
61 * NOTE: Even if device supports only some protocols, but
62 * is able to produce some skb->csum, it MUST use COMPLETE,
63 * not UNNECESSARY.
64 *
65 * PARTIAL: identical to the case for output below. This may occur
66 * on a packet received directly from another Linux OS, e.g.,
67 * a virtualised Linux kernel on the same host. The packet can
68 * be treated in the same way as UNNECESSARY except that on
69 * output (i.e., forwarding) the checksum must be filled in
70 * by the OS or the hardware.
71 *
72 * B. Checksumming on output.
73 *
74 * NONE: skb is checksummed by protocol or csum is not required.
75 *
76 * PARTIAL: device is required to csum packet as seen by hard_start_xmit
77 * from skb->csum_start to the end and to record the checksum
78 * at skb->csum_start + skb->csum_offset.
79 *
80 * Device must show its capabilities in dev->features, set
81 * at device setup time.
82 * NETIF_F_HW_CSUM - it is clever device, it is able to checksum
83 * everything.
84 * NETIF_F_NO_CSUM - loopback or reliable single hop media.
85 * NETIF_F_IP_CSUM - device is dumb. It is able to csum only
86 * TCP/UDP over IPv4. Sigh. Vendors like this
87 * way by an unknown reason. Though, see comment above
88 * about CHECKSUM_UNNECESSARY. 8)
89 * NETIF_F_IPV6_CSUM about as dumb as the last one but does IPv6 instead.
90 *
91 * Any questions? No questions, good. --ANK
92 */
93
94 struct net_device;
95 struct scatterlist;
96 struct pipe_inode_info;
97
98 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
99 struct nf_conntrack {
100 atomic_t use;
101 };
102 #endif
103
104 #ifdef CONFIG_BRIDGE_NETFILTER
105 struct nf_bridge_info {
106 atomic_t use;
107 struct net_device *physindev;
108 struct net_device *physoutdev;
109 unsigned int mask;
110 unsigned long data[32 / sizeof(unsigned long)];
111 };
112 #endif
113
114 struct sk_buff_head {
115 /* These two members must be first. */
116 struct sk_buff *next;
117 struct sk_buff *prev;
118
119 __u32 qlen;
120 spinlock_t lock;
121 };
122
123 struct sk_buff;
124
125 /* To allow 64K frame to be packed as single skb without frag_list */
126 #define MAX_SKB_FRAGS (65536/PAGE_SIZE + 2)
127
128 typedef struct skb_frag_struct skb_frag_t;
129
130 struct skb_frag_struct {
131 struct page *page;
132 __u32 page_offset;
133 __u32 size;
134 };
135
136 #define HAVE_HW_TIME_STAMP
137
138 /**
139 * struct skb_shared_hwtstamps - hardware time stamps
140 * @hwtstamp: hardware time stamp transformed into duration
141 * since arbitrary point in time
142 * @syststamp: hwtstamp transformed to system time base
143 *
144 * Software time stamps generated by ktime_get_real() are stored in
145 * skb->tstamp. The relation between the different kinds of time
146 * stamps is as follows:
147 *
148 * syststamp and tstamp can be compared against each other in
149 * arbitrary combinations. The accuracy of a
150 * syststamp/tstamp/"syststamp from other device" comparison is
151 * limited by the accuracy of the transformation into system time
152 * base. This depends on the device driver and its underlying
153 * hardware.
154 *
155 * hwtstamps can only be compared against other hwtstamps from
156 * the same device.
157 *
158 * This structure is attached to packets as part of the
159 * &skb_shared_info. Use skb_hwtstamps() to get a pointer.
160 */
161 struct skb_shared_hwtstamps {
162 ktime_t hwtstamp;
163 ktime_t syststamp;
164 };
165
166 /**
167 * struct skb_shared_tx - instructions for time stamping of outgoing packets
168 * @hardware: generate hardware time stamp
169 * @software: generate software time stamp
170 * @in_progress: device driver is going to provide
171 * hardware time stamp
172 * @flags: all shared_tx flags
173 *
174 * These flags are attached to packets as part of the
175 * &skb_shared_info. Use skb_tx() to get a pointer.
176 */
177 union skb_shared_tx {
178 struct {
179 __u8 hardware:1,
180 software:1,
181 in_progress:1;
182 };
183 __u8 flags;
184 };
185
186 /* This data is invariant across clones and lives at
187 * the end of the header data, ie. at skb->end.
188 */
189 struct skb_shared_info {
190 unsigned short nr_frags;
191 unsigned short gso_size;
192 /* Warning: this field is not always filled in (UFO)! */
193 unsigned short gso_segs;
194 unsigned short gso_type;
195 __be32 ip6_frag_id;
196 union skb_shared_tx tx_flags;
197 struct sk_buff *frag_list;
198 struct skb_shared_hwtstamps hwtstamps;
199
200 /*
201 * Warning : all fields before dataref are cleared in __alloc_skb()
202 */
203 atomic_t dataref;
204
205 skb_frag_t frags[MAX_SKB_FRAGS];
206 /* Intermediate layers must ensure that destructor_arg
207 * remains valid until skb destructor */
208 void * destructor_arg;
209 };
210
211 /* We divide dataref into two halves. The higher 16 bits hold references
212 * to the payload part of skb->data. The lower 16 bits hold references to
213 * the entire skb->data. A clone of a headerless skb holds the length of
214 * the header in skb->hdr_len.
215 *
216 * All users must obey the rule that the skb->data reference count must be
217 * greater than or equal to the payload reference count.
218 *
219 * Holding a reference to the payload part means that the user does not
220 * care about modifications to the header part of skb->data.
221 */
222 #define SKB_DATAREF_SHIFT 16
223 #define SKB_DATAREF_MASK ((1 << SKB_DATAREF_SHIFT) - 1)
224
225
226 enum {
227 SKB_FCLONE_UNAVAILABLE,
228 SKB_FCLONE_ORIG,
229 SKB_FCLONE_CLONE,
230 };
231
232 enum {
233 SKB_GSO_TCPV4 = 1 << 0,
234 SKB_GSO_UDP = 1 << 1,
235
236 /* This indicates the skb is from an untrusted source. */
237 SKB_GSO_DODGY = 1 << 2,
238
239 /* This indicates the tcp segment has CWR set. */
240 SKB_GSO_TCP_ECN = 1 << 3,
241
242 SKB_GSO_TCPV6 = 1 << 4,
243
244 SKB_GSO_FCOE = 1 << 5,
245 };
246
247 #if BITS_PER_LONG > 32
248 #define NET_SKBUFF_DATA_USES_OFFSET 1
249 #endif
250
251 #ifdef NET_SKBUFF_DATA_USES_OFFSET
252 typedef unsigned int sk_buff_data_t;
253 #else
254 typedef unsigned char *sk_buff_data_t;
255 #endif
256
257 /**
258 * struct sk_buff - socket buffer
259 * @next: Next buffer in list
260 * @prev: Previous buffer in list
261 * @sk: Socket we are owned by
262 * @tstamp: Time we arrived
263 * @dev: Device we arrived on/are leaving by
264 * @transport_header: Transport layer header
265 * @network_header: Network layer header
266 * @mac_header: Link layer header
267 * @_skb_refdst: destination entry (with norefcount bit)
268 * @sp: the security path, used for xfrm
269 * @cb: Control buffer. Free for use by every layer. Put private vars here
270 * @len: Length of actual data
271 * @data_len: Data length
272 * @mac_len: Length of link layer header
273 * @hdr_len: writable header length of cloned skb
274 * @csum: Checksum (must include start/offset pair)
275 * @csum_start: Offset from skb->head where checksumming should start
276 * @csum_offset: Offset from csum_start where checksum should be stored
277 * @local_df: allow local fragmentation
278 * @cloned: Head may be cloned (check refcnt to be sure)
279 * @nohdr: Payload reference only, must not modify header
280 * @pkt_type: Packet class
281 * @fclone: skbuff clone status
282 * @ip_summed: Driver fed us an IP checksum
283 * @priority: Packet queueing priority
284 * @users: User count - see {datagram,tcp}.c
285 * @protocol: Packet protocol from driver
286 * @truesize: Buffer size
287 * @head: Head of buffer
288 * @data: Data head pointer
289 * @tail: Tail pointer
290 * @end: End pointer
291 * @destructor: Destruct function
292 * @mark: Generic packet mark
293 * @nfct: Associated connection, if any
294 * @ipvs_property: skbuff is owned by ipvs
295 * @peeked: this packet has been seen already, so stats have been
296 * done for it, don't do them again
297 * @nf_trace: netfilter packet trace flag
298 * @nfctinfo: Relationship of this skb to the connection
299 * @nfct_reasm: netfilter conntrack re-assembly pointer
300 * @nf_bridge: Saved data about a bridged frame - see br_netfilter.c
301 * @skb_iif: ifindex of device we arrived on
302 * @rxhash: the packet hash computed on receive
303 * @queue_mapping: Queue mapping for multiqueue devices
304 * @tc_index: Traffic control index
305 * @tc_verd: traffic control verdict
306 * @ndisc_nodetype: router type (from link layer)
307 * @dma_cookie: a cookie to one of several possible DMA operations
308 * done by skb DMA functions
309 * @secmark: security marking
310 * @vlan_tci: vlan tag control information
311 */
312
313 struct sk_buff {
314 /* These two members must be first. */
315 struct sk_buff *next;
316 struct sk_buff *prev;
317
318 ktime_t tstamp;
319
320 struct sock *sk;
321 struct net_device *dev;
322
323 /*
324 * This is the control buffer. It is free to use for every
325 * layer. Please put your private variables there. If you
326 * want to keep them across layers you have to do a skb_clone()
327 * first. This is owned by whoever has the skb queued ATM.
328 */
329 char cb[48] __aligned(8);
330
331 unsigned long _skb_refdst;
332 #ifdef CONFIG_XFRM
333 struct sec_path *sp;
334 #endif
335 unsigned int len,
336 data_len;
337 __u16 mac_len,
338 hdr_len;
339 union {
340 __wsum csum;
341 struct {
342 __u16 csum_start;
343 __u16 csum_offset;
344 };
345 };
346 __u32 priority;
347 kmemcheck_bitfield_begin(flags1);
348 __u8 local_df:1,
349 cloned:1,
350 ip_summed:2,
351 nohdr:1,
352 nfctinfo:3;
353 __u8 pkt_type:3,
354 fclone:2,
355 ipvs_property:1,
356 peeked:1,
357 nf_trace:1;
358 kmemcheck_bitfield_end(flags1);
359 __be16 protocol;
360
361 void (*destructor)(struct sk_buff *skb);
362 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
363 struct nf_conntrack *nfct;
364 struct sk_buff *nfct_reasm;
365 #endif
366 #ifdef CONFIG_BRIDGE_NETFILTER
367 struct nf_bridge_info *nf_bridge;
368 #endif
369
370 int skb_iif;
371 #ifdef CONFIG_NET_SCHED
372 __u16 tc_index; /* traffic control index */
373 #ifdef CONFIG_NET_CLS_ACT
374 __u16 tc_verd; /* traffic control verdict */
375 #endif
376 #endif
377
378 __u32 rxhash;
379
380 kmemcheck_bitfield_begin(flags2);
381 __u16 queue_mapping:16;
382 #ifdef CONFIG_IPV6_NDISC_NODETYPE
383 __u8 ndisc_nodetype:2,
384 deliver_no_wcard:1;
385 #else
386 __u8 deliver_no_wcard:1;
387 #endif
388 kmemcheck_bitfield_end(flags2);
389
390 /* 0/14 bit hole */
391
392 #ifdef CONFIG_NET_DMA
393 dma_cookie_t dma_cookie;
394 #endif
395 #ifdef CONFIG_NETWORK_SECMARK
396 __u32 secmark;
397 #endif
398 union {
399 __u32 mark;
400 __u32 dropcount;
401 };
402
403 __u16 vlan_tci;
404
405 sk_buff_data_t transport_header;
406 sk_buff_data_t network_header;
407 sk_buff_data_t mac_header;
408 /* These elements must be at the end, see alloc_skb() for details. */
409 sk_buff_data_t tail;
410 sk_buff_data_t end;
411 unsigned char *head,
412 *data;
413 unsigned int truesize;
414 atomic_t users;
415 };
416
417 #ifdef __KERNEL__
418 /*
419 * Handling routines are only of interest to the kernel
420 */
421 #include <linux/slab.h>
422
423 #include <asm/system.h>
424
425 /*
426 * skb might have a dst pointer attached, refcounted or not.
427 * _skb_refdst low order bit is set if refcount was _not_ taken
428 */
429 #define SKB_DST_NOREF 1UL
430 #define SKB_DST_PTRMASK ~(SKB_DST_NOREF)
431
432 /**
433 * skb_dst - returns skb dst_entry
434 * @skb: buffer
435 *
436 * Returns skb dst_entry, regardless of reference taken or not.
437 */
438 static inline struct dst_entry *skb_dst(const struct sk_buff *skb)
439 {
440 /* If refdst was not refcounted, check we still are in a
441 * rcu_read_lock section
442 */
443 WARN_ON((skb->_skb_refdst & SKB_DST_NOREF) &&
444 !rcu_read_lock_held() &&
445 !rcu_read_lock_bh_held());
446 return (struct dst_entry *)(skb->_skb_refdst & SKB_DST_PTRMASK);
447 }
448
449 /**
450 * skb_dst_set - sets skb dst
451 * @skb: buffer
452 * @dst: dst entry
453 *
454 * Sets skb dst, assuming a reference was taken on dst and should
455 * be released by skb_dst_drop()
456 */
457 static inline void skb_dst_set(struct sk_buff *skb, struct dst_entry *dst)
458 {
459 skb->_skb_refdst = (unsigned long)dst;
460 }
461
462 /**
463 * skb_dst_set_noref - sets skb dst, without a reference
464 * @skb: buffer
465 * @dst: dst entry
466 *
467 * Sets skb dst, assuming a reference was not taken on dst
468 * skb_dst_drop() should not dst_release() this dst
469 */
470 static inline void skb_dst_set_noref(struct sk_buff *skb, struct dst_entry *dst)
471 {
472 WARN_ON(!rcu_read_lock_held() && !rcu_read_lock_bh_held());
473 skb->_skb_refdst = (unsigned long)dst | SKB_DST_NOREF;
474 }
475
476 /**
477 * skb_dst_is_noref - Test if skb dst isnt refcounted
478 * @skb: buffer
479 */
480 static inline bool skb_dst_is_noref(const struct sk_buff *skb)
481 {
482 return (skb->_skb_refdst & SKB_DST_NOREF) && skb_dst(skb);
483 }
484
485 static inline struct rtable *skb_rtable(const struct sk_buff *skb)
486 {
487 return (struct rtable *)skb_dst(skb);
488 }
489
490 extern void kfree_skb(struct sk_buff *skb);
491 extern void consume_skb(struct sk_buff *skb);
492 extern void __kfree_skb(struct sk_buff *skb);
493 extern struct sk_buff *__alloc_skb(unsigned int size,
494 gfp_t priority, int fclone, int node);
495 static inline struct sk_buff *alloc_skb(unsigned int size,
496 gfp_t priority)
497 {
498 return __alloc_skb(size, priority, 0, -1);
499 }
500
501 static inline struct sk_buff *alloc_skb_fclone(unsigned int size,
502 gfp_t priority)
503 {
504 return __alloc_skb(size, priority, 1, -1);
505 }
506
507 extern bool skb_recycle_check(struct sk_buff *skb, int skb_size);
508
509 extern struct sk_buff *skb_morph(struct sk_buff *dst, struct sk_buff *src);
510 extern struct sk_buff *skb_clone(struct sk_buff *skb,
511 gfp_t priority);
512 extern struct sk_buff *skb_copy(const struct sk_buff *skb,
513 gfp_t priority);
514 extern struct sk_buff *pskb_copy(struct sk_buff *skb,
515 gfp_t gfp_mask);
516 extern int pskb_expand_head(struct sk_buff *skb,
517 int nhead, int ntail,
518 gfp_t gfp_mask);
519 extern struct sk_buff *skb_realloc_headroom(struct sk_buff *skb,
520 unsigned int headroom);
521 extern struct sk_buff *skb_copy_expand(const struct sk_buff *skb,
522 int newheadroom, int newtailroom,
523 gfp_t priority);
524 extern int skb_to_sgvec(struct sk_buff *skb,
525 struct scatterlist *sg, int offset,
526 int len);
527 extern int skb_cow_data(struct sk_buff *skb, int tailbits,
528 struct sk_buff **trailer);
529 extern int skb_pad(struct sk_buff *skb, int pad);
530 #define dev_kfree_skb(a) consume_skb(a)
531
532 extern int skb_append_datato_frags(struct sock *sk, struct sk_buff *skb,
533 int getfrag(void *from, char *to, int offset,
534 int len,int odd, struct sk_buff *skb),
535 void *from, int length);
536
537 struct skb_seq_state {
538 __u32 lower_offset;
539 __u32 upper_offset;
540 __u32 frag_idx;
541 __u32 stepped_offset;
542 struct sk_buff *root_skb;
543 struct sk_buff *cur_skb;
544 __u8 *frag_data;
545 };
546
547 extern void skb_prepare_seq_read(struct sk_buff *skb,
548 unsigned int from, unsigned int to,
549 struct skb_seq_state *st);
550 extern unsigned int skb_seq_read(unsigned int consumed, const u8 **data,
551 struct skb_seq_state *st);
552 extern void skb_abort_seq_read(struct skb_seq_state *st);
553
554 extern unsigned int skb_find_text(struct sk_buff *skb, unsigned int from,
555 unsigned int to, struct ts_config *config,
556 struct ts_state *state);
557
558 #ifdef NET_SKBUFF_DATA_USES_OFFSET
559 static inline unsigned char *skb_end_pointer(const struct sk_buff *skb)
560 {
561 return skb->head + skb->end;
562 }
563 #else
564 static inline unsigned char *skb_end_pointer(const struct sk_buff *skb)
565 {
566 return skb->end;
567 }
568 #endif
569
570 /* Internal */
571 #define skb_shinfo(SKB) ((struct skb_shared_info *)(skb_end_pointer(SKB)))
572
573 static inline struct skb_shared_hwtstamps *skb_hwtstamps(struct sk_buff *skb)
574 {
575 return &skb_shinfo(skb)->hwtstamps;
576 }
577
578 static inline union skb_shared_tx *skb_tx(struct sk_buff *skb)
579 {
580 return &skb_shinfo(skb)->tx_flags;
581 }
582
583 /**
584 * skb_queue_empty - check if a queue is empty
585 * @list: queue head
586 *
587 * Returns true if the queue is empty, false otherwise.
588 */
589 static inline int skb_queue_empty(const struct sk_buff_head *list)
590 {
591 return list->next == (struct sk_buff *)list;
592 }
593
594 /**
595 * skb_queue_is_last - check if skb is the last entry in the queue
596 * @list: queue head
597 * @skb: buffer
598 *
599 * Returns true if @skb is the last buffer on the list.
600 */
601 static inline bool skb_queue_is_last(const struct sk_buff_head *list,
602 const struct sk_buff *skb)
603 {
604 return (skb->next == (struct sk_buff *) list);
605 }
606
607 /**
608 * skb_queue_is_first - check if skb is the first entry in the queue
609 * @list: queue head
610 * @skb: buffer
611 *
612 * Returns true if @skb is the first buffer on the list.
613 */
614 static inline bool skb_queue_is_first(const struct sk_buff_head *list,
615 const struct sk_buff *skb)
616 {
617 return (skb->prev == (struct sk_buff *) list);
618 }
619
620 /**
621 * skb_queue_next - return the next packet in the queue
622 * @list: queue head
623 * @skb: current buffer
624 *
625 * Return the next packet in @list after @skb. It is only valid to
626 * call this if skb_queue_is_last() evaluates to false.
627 */
628 static inline struct sk_buff *skb_queue_next(const struct sk_buff_head *list,
629 const struct sk_buff *skb)
630 {
631 /* This BUG_ON may seem severe, but if we just return then we
632 * are going to dereference garbage.
633 */
634 BUG_ON(skb_queue_is_last(list, skb));
635 return skb->next;
636 }
637
638 /**
639 * skb_queue_prev - return the prev packet in the queue
640 * @list: queue head
641 * @skb: current buffer
642 *
643 * Return the prev packet in @list before @skb. It is only valid to
644 * call this if skb_queue_is_first() evaluates to false.
645 */
646 static inline struct sk_buff *skb_queue_prev(const struct sk_buff_head *list,
647 const struct sk_buff *skb)
648 {
649 /* This BUG_ON may seem severe, but if we just return then we
650 * are going to dereference garbage.
651 */
652 BUG_ON(skb_queue_is_first(list, skb));
653 return skb->prev;
654 }
655
656 /**
657 * skb_get - reference buffer
658 * @skb: buffer to reference
659 *
660 * Makes another reference to a socket buffer and returns a pointer
661 * to the buffer.
662 */
663 static inline struct sk_buff *skb_get(struct sk_buff *skb)
664 {
665 atomic_inc(&skb->users);
666 return skb;
667 }
668
669 /*
670 * If users == 1, we are the only owner and are can avoid redundant
671 * atomic change.
672 */
673
674 /**
675 * skb_cloned - is the buffer a clone
676 * @skb: buffer to check
677 *
678 * Returns true if the buffer was generated with skb_clone() and is
679 * one of multiple shared copies of the buffer. Cloned buffers are
680 * shared data so must not be written to under normal circumstances.
681 */
682 static inline int skb_cloned(const struct sk_buff *skb)
683 {
684 return skb->cloned &&
685 (atomic_read(&skb_shinfo(skb)->dataref) & SKB_DATAREF_MASK) != 1;
686 }
687
688 /**
689 * skb_header_cloned - is the header a clone
690 * @skb: buffer to check
691 *
692 * Returns true if modifying the header part of the buffer requires
693 * the data to be copied.
694 */
695 static inline int skb_header_cloned(const struct sk_buff *skb)
696 {
697 int dataref;
698
699 if (!skb->cloned)
700 return 0;
701
702 dataref = atomic_read(&skb_shinfo(skb)->dataref);
703 dataref = (dataref & SKB_DATAREF_MASK) - (dataref >> SKB_DATAREF_SHIFT);
704 return dataref != 1;
705 }
706
707 /**
708 * skb_header_release - release reference to header
709 * @skb: buffer to operate on
710 *
711 * Drop a reference to the header part of the buffer. This is done
712 * by acquiring a payload reference. You must not read from the header
713 * part of skb->data after this.
714 */
715 static inline void skb_header_release(struct sk_buff *skb)
716 {
717 BUG_ON(skb->nohdr);
718 skb->nohdr = 1;
719 atomic_add(1 << SKB_DATAREF_SHIFT, &skb_shinfo(skb)->dataref);
720 }
721
722 /**
723 * skb_shared - is the buffer shared
724 * @skb: buffer to check
725 *
726 * Returns true if more than one person has a reference to this
727 * buffer.
728 */
729 static inline int skb_shared(const struct sk_buff *skb)
730 {
731 return atomic_read(&skb->users) != 1;
732 }
733
734 /**
735 * skb_share_check - check if buffer is shared and if so clone it
736 * @skb: buffer to check
737 * @pri: priority for memory allocation
738 *
739 * If the buffer is shared the buffer is cloned and the old copy
740 * drops a reference. A new clone with a single reference is returned.
741 * If the buffer is not shared the original buffer is returned. When
742 * being called from interrupt status or with spinlocks held pri must
743 * be GFP_ATOMIC.
744 *
745 * NULL is returned on a memory allocation failure.
746 */
747 static inline struct sk_buff *skb_share_check(struct sk_buff *skb,
748 gfp_t pri)
749 {
750 might_sleep_if(pri & __GFP_WAIT);
751 if (skb_shared(skb)) {
752 struct sk_buff *nskb = skb_clone(skb, pri);
753 kfree_skb(skb);
754 skb = nskb;
755 }
756 return skb;
757 }
758
759 /*
760 * Copy shared buffers into a new sk_buff. We effectively do COW on
761 * packets to handle cases where we have a local reader and forward
762 * and a couple of other messy ones. The normal one is tcpdumping
763 * a packet thats being forwarded.
764 */
765
766 /**
767 * skb_unshare - make a copy of a shared buffer
768 * @skb: buffer to check
769 * @pri: priority for memory allocation
770 *
771 * If the socket buffer is a clone then this function creates a new
772 * copy of the data, drops a reference count on the old copy and returns
773 * the new copy with the reference count at 1. If the buffer is not a clone
774 * the original buffer is returned. When called with a spinlock held or
775 * from interrupt state @pri must be %GFP_ATOMIC
776 *
777 * %NULL is returned on a memory allocation failure.
778 */
779 static inline struct sk_buff *skb_unshare(struct sk_buff *skb,
780 gfp_t pri)
781 {
782 might_sleep_if(pri & __GFP_WAIT);
783 if (skb_cloned(skb)) {
784 struct sk_buff *nskb = skb_copy(skb, pri);
785 kfree_skb(skb); /* Free our shared copy */
786 skb = nskb;
787 }
788 return skb;
789 }
790
791 /**
792 * skb_peek - peek at the head of an &sk_buff_head
793 * @list_: list to peek at
794 *
795 * Peek an &sk_buff. Unlike most other operations you _MUST_
796 * be careful with this one. A peek leaves the buffer on the
797 * list and someone else may run off with it. You must hold
798 * the appropriate locks or have a private queue to do this.
799 *
800 * Returns %NULL for an empty list or a pointer to the head element.
801 * The reference count is not incremented and the reference is therefore
802 * volatile. Use with caution.
803 */
804 static inline struct sk_buff *skb_peek(struct sk_buff_head *list_)
805 {
806 struct sk_buff *list = ((struct sk_buff *)list_)->next;
807 if (list == (struct sk_buff *)list_)
808 list = NULL;
809 return list;
810 }
811
812 /**
813 * skb_peek_tail - peek at the tail of an &sk_buff_head
814 * @list_: list to peek at
815 *
816 * Peek an &sk_buff. Unlike most other operations you _MUST_
817 * be careful with this one. A peek leaves the buffer on the
818 * list and someone else may run off with it. You must hold
819 * the appropriate locks or have a private queue to do this.
820 *
821 * Returns %NULL for an empty list or a pointer to the tail element.
822 * The reference count is not incremented and the reference is therefore
823 * volatile. Use with caution.
824 */
825 static inline struct sk_buff *skb_peek_tail(struct sk_buff_head *list_)
826 {
827 struct sk_buff *list = ((struct sk_buff *)list_)->prev;
828 if (list == (struct sk_buff *)list_)
829 list = NULL;
830 return list;
831 }
832
833 /**
834 * skb_queue_len - get queue length
835 * @list_: list to measure
836 *
837 * Return the length of an &sk_buff queue.
838 */
839 static inline __u32 skb_queue_len(const struct sk_buff_head *list_)
840 {
841 return list_->qlen;
842 }
843
844 /**
845 * __skb_queue_head_init - initialize non-spinlock portions of sk_buff_head
846 * @list: queue to initialize
847 *
848 * This initializes only the list and queue length aspects of
849 * an sk_buff_head object. This allows to initialize the list
850 * aspects of an sk_buff_head without reinitializing things like
851 * the spinlock. It can also be used for on-stack sk_buff_head
852 * objects where the spinlock is known to not be used.
853 */
854 static inline void __skb_queue_head_init(struct sk_buff_head *list)
855 {
856 list->prev = list->next = (struct sk_buff *)list;
857 list->qlen = 0;
858 }
859
860 /*
861 * This function creates a split out lock class for each invocation;
862 * this is needed for now since a whole lot of users of the skb-queue
863 * infrastructure in drivers have different locking usage (in hardirq)
864 * than the networking core (in softirq only). In the long run either the
865 * network layer or drivers should need annotation to consolidate the
866 * main types of usage into 3 classes.
867 */
868 static inline void skb_queue_head_init(struct sk_buff_head *list)
869 {
870 spin_lock_init(&list->lock);
871 __skb_queue_head_init(list);
872 }
873
874 static inline void skb_queue_head_init_class(struct sk_buff_head *list,
875 struct lock_class_key *class)
876 {
877 skb_queue_head_init(list);
878 lockdep_set_class(&list->lock, class);
879 }
880
881 /*
882 * Insert an sk_buff on a list.
883 *
884 * The "__skb_xxxx()" functions are the non-atomic ones that
885 * can only be called with interrupts disabled.
886 */
887 extern void skb_insert(struct sk_buff *old, struct sk_buff *newsk, struct sk_buff_head *list);
888 static inline void __skb_insert(struct sk_buff *newsk,
889 struct sk_buff *prev, struct sk_buff *next,
890 struct sk_buff_head *list)
891 {
892 newsk->next = next;
893 newsk->prev = prev;
894 next->prev = prev->next = newsk;
895 list->qlen++;
896 }
897
898 static inline void __skb_queue_splice(const struct sk_buff_head *list,
899 struct sk_buff *prev,
900 struct sk_buff *next)
901 {
902 struct sk_buff *first = list->next;
903 struct sk_buff *last = list->prev;
904
905 first->prev = prev;
906 prev->next = first;
907
908 last->next = next;
909 next->prev = last;
910 }
911
912 /**
913 * skb_queue_splice - join two skb lists, this is designed for stacks
914 * @list: the new list to add
915 * @head: the place to add it in the first list
916 */
917 static inline void skb_queue_splice(const struct sk_buff_head *list,
918 struct sk_buff_head *head)
919 {
920 if (!skb_queue_empty(list)) {
921 __skb_queue_splice(list, (struct sk_buff *) head, head->next);
922 head->qlen += list->qlen;
923 }
924 }
925
926 /**
927 * skb_queue_splice - join two skb lists and reinitialise the emptied list
928 * @list: the new list to add
929 * @head: the place to add it in the first list
930 *
931 * The list at @list is reinitialised
932 */
933 static inline void skb_queue_splice_init(struct sk_buff_head *list,
934 struct sk_buff_head *head)
935 {
936 if (!skb_queue_empty(list)) {
937 __skb_queue_splice(list, (struct sk_buff *) head, head->next);
938 head->qlen += list->qlen;
939 __skb_queue_head_init(list);
940 }
941 }
942
943 /**
944 * skb_queue_splice_tail - join two skb lists, each list being a queue
945 * @list: the new list to add
946 * @head: the place to add it in the first list
947 */
948 static inline void skb_queue_splice_tail(const struct sk_buff_head *list,
949 struct sk_buff_head *head)
950 {
951 if (!skb_queue_empty(list)) {
952 __skb_queue_splice(list, head->prev, (struct sk_buff *) head);
953 head->qlen += list->qlen;
954 }
955 }
956
957 /**
958 * skb_queue_splice_tail - join two skb lists and reinitialise the emptied list
959 * @list: the new list to add
960 * @head: the place to add it in the first list
961 *
962 * Each of the lists is a queue.
963 * The list at @list is reinitialised
964 */
965 static inline void skb_queue_splice_tail_init(struct sk_buff_head *list,
966 struct sk_buff_head *head)
967 {
968 if (!skb_queue_empty(list)) {
969 __skb_queue_splice(list, head->prev, (struct sk_buff *) head);
970 head->qlen += list->qlen;
971 __skb_queue_head_init(list);
972 }
973 }
974
975 /**
976 * __skb_queue_after - queue a buffer at the list head
977 * @list: list to use
978 * @prev: place after this buffer
979 * @newsk: buffer to queue
980 *
981 * Queue a buffer int the middle of a list. This function takes no locks
982 * and you must therefore hold required locks before calling it.
983 *
984 * A buffer cannot be placed on two lists at the same time.
985 */
986 static inline void __skb_queue_after(struct sk_buff_head *list,
987 struct sk_buff *prev,
988 struct sk_buff *newsk)
989 {
990 __skb_insert(newsk, prev, prev->next, list);
991 }
992
993 extern void skb_append(struct sk_buff *old, struct sk_buff *newsk,
994 struct sk_buff_head *list);
995
996 static inline void __skb_queue_before(struct sk_buff_head *list,
997 struct sk_buff *next,
998 struct sk_buff *newsk)
999 {
1000 __skb_insert(newsk, next->prev, next, list);
1001 }
1002
1003 /**
1004 * __skb_queue_head - queue a buffer at the list head
1005 * @list: list to use
1006 * @newsk: buffer to queue
1007 *
1008 * Queue a buffer at the start of a list. This function takes no locks
1009 * and you must therefore hold required locks before calling it.
1010 *
1011 * A buffer cannot be placed on two lists at the same time.
1012 */
1013 extern void skb_queue_head(struct sk_buff_head *list, struct sk_buff *newsk);
1014 static inline void __skb_queue_head(struct sk_buff_head *list,
1015 struct sk_buff *newsk)
1016 {
1017 __skb_queue_after(list, (struct sk_buff *)list, newsk);
1018 }
1019
1020 /**
1021 * __skb_queue_tail - queue a buffer at the list tail
1022 * @list: list to use
1023 * @newsk: buffer to queue
1024 *
1025 * Queue a buffer at the end of a list. This function takes no locks
1026 * and you must therefore hold required locks before calling it.
1027 *
1028 * A buffer cannot be placed on two lists at the same time.
1029 */
1030 extern void skb_queue_tail(struct sk_buff_head *list, struct sk_buff *newsk);
1031 static inline void __skb_queue_tail(struct sk_buff_head *list,
1032 struct sk_buff *newsk)
1033 {
1034 __skb_queue_before(list, (struct sk_buff *)list, newsk);
1035 }
1036
1037 /*
1038 * remove sk_buff from list. _Must_ be called atomically, and with
1039 * the list known..
1040 */
1041 extern void skb_unlink(struct sk_buff *skb, struct sk_buff_head *list);
1042 static inline void __skb_unlink(struct sk_buff *skb, struct sk_buff_head *list)
1043 {
1044 struct sk_buff *next, *prev;
1045
1046 list->qlen--;
1047 next = skb->next;
1048 prev = skb->prev;
1049 skb->next = skb->prev = NULL;
1050 next->prev = prev;
1051 prev->next = next;
1052 }
1053
1054 /**
1055 * __skb_dequeue - remove from the head of the queue
1056 * @list: list to dequeue from
1057 *
1058 * Remove the head of the list. This function does not take any locks
1059 * so must be used with appropriate locks held only. The head item is
1060 * returned or %NULL if the list is empty.
1061 */
1062 extern struct sk_buff *skb_dequeue(struct sk_buff_head *list);
1063 static inline struct sk_buff *__skb_dequeue(struct sk_buff_head *list)
1064 {
1065 struct sk_buff *skb = skb_peek(list);
1066 if (skb)
1067 __skb_unlink(skb, list);
1068 return skb;
1069 }
1070
1071 /**
1072 * __skb_dequeue_tail - remove from the tail of the queue
1073 * @list: list to dequeue from
1074 *
1075 * Remove the tail of the list. This function does not take any locks
1076 * so must be used with appropriate locks held only. The tail item is
1077 * returned or %NULL if the list is empty.
1078 */
1079 extern struct sk_buff *skb_dequeue_tail(struct sk_buff_head *list);
1080 static inline struct sk_buff *__skb_dequeue_tail(struct sk_buff_head *list)
1081 {
1082 struct sk_buff *skb = skb_peek_tail(list);
1083 if (skb)
1084 __skb_unlink(skb, list);
1085 return skb;
1086 }
1087
1088
1089 static inline int skb_is_nonlinear(const struct sk_buff *skb)
1090 {
1091 return skb->data_len;
1092 }
1093
1094 static inline unsigned int skb_headlen(const struct sk_buff *skb)
1095 {
1096 return skb->len - skb->data_len;
1097 }
1098
1099 static inline int skb_pagelen(const struct sk_buff *skb)
1100 {
1101 int i, len = 0;
1102
1103 for (i = (int)skb_shinfo(skb)->nr_frags - 1; i >= 0; i--)
1104 len += skb_shinfo(skb)->frags[i].size;
1105 return len + skb_headlen(skb);
1106 }
1107
1108 static inline void skb_fill_page_desc(struct sk_buff *skb, int i,
1109 struct page *page, int off, int size)
1110 {
1111 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
1112
1113 frag->page = page;
1114 frag->page_offset = off;
1115 frag->size = size;
1116 skb_shinfo(skb)->nr_frags = i + 1;
1117 }
1118
1119 extern void skb_add_rx_frag(struct sk_buff *skb, int i, struct page *page,
1120 int off, int size);
1121
1122 #define SKB_PAGE_ASSERT(skb) BUG_ON(skb_shinfo(skb)->nr_frags)
1123 #define SKB_FRAG_ASSERT(skb) BUG_ON(skb_has_frags(skb))
1124 #define SKB_LINEAR_ASSERT(skb) BUG_ON(skb_is_nonlinear(skb))
1125
1126 #ifdef NET_SKBUFF_DATA_USES_OFFSET
1127 static inline unsigned char *skb_tail_pointer(const struct sk_buff *skb)
1128 {
1129 return skb->head + skb->tail;
1130 }
1131
1132 static inline void skb_reset_tail_pointer(struct sk_buff *skb)
1133 {
1134 skb->tail = skb->data - skb->head;
1135 }
1136
1137 static inline void skb_set_tail_pointer(struct sk_buff *skb, const int offset)
1138 {
1139 skb_reset_tail_pointer(skb);
1140 skb->tail += offset;
1141 }
1142 #else /* NET_SKBUFF_DATA_USES_OFFSET */
1143 static inline unsigned char *skb_tail_pointer(const struct sk_buff *skb)
1144 {
1145 return skb->tail;
1146 }
1147
1148 static inline void skb_reset_tail_pointer(struct sk_buff *skb)
1149 {
1150 skb->tail = skb->data;
1151 }
1152
1153 static inline void skb_set_tail_pointer(struct sk_buff *skb, const int offset)
1154 {
1155 skb->tail = skb->data + offset;
1156 }
1157
1158 #endif /* NET_SKBUFF_DATA_USES_OFFSET */
1159
1160 /*
1161 * Add data to an sk_buff
1162 */
1163 extern unsigned char *skb_put(struct sk_buff *skb, unsigned int len);
1164 static inline unsigned char *__skb_put(struct sk_buff *skb, unsigned int len)
1165 {
1166 unsigned char *tmp = skb_tail_pointer(skb);
1167 SKB_LINEAR_ASSERT(skb);
1168 skb->tail += len;
1169 skb->len += len;
1170 return tmp;
1171 }
1172
1173 extern unsigned char *skb_push(struct sk_buff *skb, unsigned int len);
1174 static inline unsigned char *__skb_push(struct sk_buff *skb, unsigned int len)
1175 {
1176 skb->data -= len;
1177 skb->len += len;
1178 return skb->data;
1179 }
1180
1181 extern unsigned char *skb_pull(struct sk_buff *skb, unsigned int len);
1182 static inline unsigned char *__skb_pull(struct sk_buff *skb, unsigned int len)
1183 {
1184 skb->len -= len;
1185 BUG_ON(skb->len < skb->data_len);
1186 return skb->data += len;
1187 }
1188
1189 static inline unsigned char *skb_pull_inline(struct sk_buff *skb, unsigned int len)
1190 {
1191 return unlikely(len > skb->len) ? NULL : __skb_pull(skb, len);
1192 }
1193
1194 extern unsigned char *__pskb_pull_tail(struct sk_buff *skb, int delta);
1195
1196 static inline unsigned char *__pskb_pull(struct sk_buff *skb, unsigned int len)
1197 {
1198 if (len > skb_headlen(skb) &&
1199 !__pskb_pull_tail(skb, len - skb_headlen(skb)))
1200 return NULL;
1201 skb->len -= len;
1202 return skb->data += len;
1203 }
1204
1205 static inline unsigned char *pskb_pull(struct sk_buff *skb, unsigned int len)
1206 {
1207 return unlikely(len > skb->len) ? NULL : __pskb_pull(skb, len);
1208 }
1209
1210 static inline int pskb_may_pull(struct sk_buff *skb, unsigned int len)
1211 {
1212 if (likely(len <= skb_headlen(skb)))
1213 return 1;
1214 if (unlikely(len > skb->len))
1215 return 0;
1216 return __pskb_pull_tail(skb, len - skb_headlen(skb)) != NULL;
1217 }
1218
1219 /**
1220 * skb_headroom - bytes at buffer head
1221 * @skb: buffer to check
1222 *
1223 * Return the number of bytes of free space at the head of an &sk_buff.
1224 */
1225 static inline unsigned int skb_headroom(const struct sk_buff *skb)
1226 {
1227 return skb->data - skb->head;
1228 }
1229
1230 /**
1231 * skb_tailroom - bytes at buffer end
1232 * @skb: buffer to check
1233 *
1234 * Return the number of bytes of free space at the tail of an sk_buff
1235 */
1236 static inline int skb_tailroom(const struct sk_buff *skb)
1237 {
1238 return skb_is_nonlinear(skb) ? 0 : skb->end - skb->tail;
1239 }
1240
1241 /**
1242 * skb_reserve - adjust headroom
1243 * @skb: buffer to alter
1244 * @len: bytes to move
1245 *
1246 * Increase the headroom of an empty &sk_buff by reducing the tail
1247 * room. This is only allowed for an empty buffer.
1248 */
1249 static inline void skb_reserve(struct sk_buff *skb, int len)
1250 {
1251 skb->data += len;
1252 skb->tail += len;
1253 }
1254
1255 #ifdef NET_SKBUFF_DATA_USES_OFFSET
1256 static inline unsigned char *skb_transport_header(const struct sk_buff *skb)
1257 {
1258 return skb->head + skb->transport_header;
1259 }
1260
1261 static inline void skb_reset_transport_header(struct sk_buff *skb)
1262 {
1263 skb->transport_header = skb->data - skb->head;
1264 }
1265
1266 static inline void skb_set_transport_header(struct sk_buff *skb,
1267 const int offset)
1268 {
1269 skb_reset_transport_header(skb);
1270 skb->transport_header += offset;
1271 }
1272
1273 static inline unsigned char *skb_network_header(const struct sk_buff *skb)
1274 {
1275 return skb->head + skb->network_header;
1276 }
1277
1278 static inline void skb_reset_network_header(struct sk_buff *skb)
1279 {
1280 skb->network_header = skb->data - skb->head;
1281 }
1282
1283 static inline void skb_set_network_header(struct sk_buff *skb, const int offset)
1284 {
1285 skb_reset_network_header(skb);
1286 skb->network_header += offset;
1287 }
1288
1289 static inline unsigned char *skb_mac_header(const struct sk_buff *skb)
1290 {
1291 return skb->head + skb->mac_header;
1292 }
1293
1294 static inline int skb_mac_header_was_set(const struct sk_buff *skb)
1295 {
1296 return skb->mac_header != ~0U;
1297 }
1298
1299 static inline void skb_reset_mac_header(struct sk_buff *skb)
1300 {
1301 skb->mac_header = skb->data - skb->head;
1302 }
1303
1304 static inline void skb_set_mac_header(struct sk_buff *skb, const int offset)
1305 {
1306 skb_reset_mac_header(skb);
1307 skb->mac_header += offset;
1308 }
1309
1310 #else /* NET_SKBUFF_DATA_USES_OFFSET */
1311
1312 static inline unsigned char *skb_transport_header(const struct sk_buff *skb)
1313 {
1314 return skb->transport_header;
1315 }
1316
1317 static inline void skb_reset_transport_header(struct sk_buff *skb)
1318 {
1319 skb->transport_header = skb->data;
1320 }
1321
1322 static inline void skb_set_transport_header(struct sk_buff *skb,
1323 const int offset)
1324 {
1325 skb->transport_header = skb->data + offset;
1326 }
1327
1328 static inline unsigned char *skb_network_header(const struct sk_buff *skb)
1329 {
1330 return skb->network_header;
1331 }
1332
1333 static inline void skb_reset_network_header(struct sk_buff *skb)
1334 {
1335 skb->network_header = skb->data;
1336 }
1337
1338 static inline void skb_set_network_header(struct sk_buff *skb, const int offset)
1339 {
1340 skb->network_header = skb->data + offset;
1341 }
1342
1343 static inline unsigned char *skb_mac_header(const struct sk_buff *skb)
1344 {
1345 return skb->mac_header;
1346 }
1347
1348 static inline int skb_mac_header_was_set(const struct sk_buff *skb)
1349 {
1350 return skb->mac_header != NULL;
1351 }
1352
1353 static inline void skb_reset_mac_header(struct sk_buff *skb)
1354 {
1355 skb->mac_header = skb->data;
1356 }
1357
1358 static inline void skb_set_mac_header(struct sk_buff *skb, const int offset)
1359 {
1360 skb->mac_header = skb->data + offset;
1361 }
1362 #endif /* NET_SKBUFF_DATA_USES_OFFSET */
1363
1364 static inline int skb_transport_offset(const struct sk_buff *skb)
1365 {
1366 return skb_transport_header(skb) - skb->data;
1367 }
1368
1369 static inline u32 skb_network_header_len(const struct sk_buff *skb)
1370 {
1371 return skb->transport_header - skb->network_header;
1372 }
1373
1374 static inline int skb_network_offset(const struct sk_buff *skb)
1375 {
1376 return skb_network_header(skb) - skb->data;
1377 }
1378
1379 /*
1380 * CPUs often take a performance hit when accessing unaligned memory
1381 * locations. The actual performance hit varies, it can be small if the
1382 * hardware handles it or large if we have to take an exception and fix it
1383 * in software.
1384 *
1385 * Since an ethernet header is 14 bytes network drivers often end up with
1386 * the IP header at an unaligned offset. The IP header can be aligned by
1387 * shifting the start of the packet by 2 bytes. Drivers should do this
1388 * with:
1389 *
1390 * skb_reserve(skb, NET_IP_ALIGN);
1391 *
1392 * The downside to this alignment of the IP header is that the DMA is now
1393 * unaligned. On some architectures the cost of an unaligned DMA is high
1394 * and this cost outweighs the gains made by aligning the IP header.
1395 *
1396 * Since this trade off varies between architectures, we allow NET_IP_ALIGN
1397 * to be overridden.
1398 */
1399 #ifndef NET_IP_ALIGN
1400 #define NET_IP_ALIGN 2
1401 #endif
1402
1403 /*
1404 * The networking layer reserves some headroom in skb data (via
1405 * dev_alloc_skb). This is used to avoid having to reallocate skb data when
1406 * the header has to grow. In the default case, if the header has to grow
1407 * 32 bytes or less we avoid the reallocation.
1408 *
1409 * Unfortunately this headroom changes the DMA alignment of the resulting
1410 * network packet. As for NET_IP_ALIGN, this unaligned DMA is expensive
1411 * on some architectures. An architecture can override this value,
1412 * perhaps setting it to a cacheline in size (since that will maintain
1413 * cacheline alignment of the DMA). It must be a power of 2.
1414 *
1415 * Various parts of the networking layer expect at least 32 bytes of
1416 * headroom, you should not reduce this.
1417 * With RPS, we raised NET_SKB_PAD to 64 so that get_rps_cpus() fetches span
1418 * a 64 bytes aligned block to fit modern (>= 64 bytes) cache line sizes
1419 * NET_IP_ALIGN(2) + ethernet_header(14) + IP_header(20/40) + ports(8)
1420 */
1421 #ifndef NET_SKB_PAD
1422 #define NET_SKB_PAD 64
1423 #endif
1424
1425 extern int ___pskb_trim(struct sk_buff *skb, unsigned int len);
1426
1427 static inline void __skb_trim(struct sk_buff *skb, unsigned int len)
1428 {
1429 if (unlikely(skb->data_len)) {
1430 WARN_ON(1);
1431 return;
1432 }
1433 skb->len = len;
1434 skb_set_tail_pointer(skb, len);
1435 }
1436
1437 extern void skb_trim(struct sk_buff *skb, unsigned int len);
1438
1439 static inline int __pskb_trim(struct sk_buff *skb, unsigned int len)
1440 {
1441 if (skb->data_len)
1442 return ___pskb_trim(skb, len);
1443 __skb_trim(skb, len);
1444 return 0;
1445 }
1446
1447 static inline int pskb_trim(struct sk_buff *skb, unsigned int len)
1448 {
1449 return (len < skb->len) ? __pskb_trim(skb, len) : 0;
1450 }
1451
1452 /**
1453 * pskb_trim_unique - remove end from a paged unique (not cloned) buffer
1454 * @skb: buffer to alter
1455 * @len: new length
1456 *
1457 * This is identical to pskb_trim except that the caller knows that
1458 * the skb is not cloned so we should never get an error due to out-
1459 * of-memory.
1460 */
1461 static inline void pskb_trim_unique(struct sk_buff *skb, unsigned int len)
1462 {
1463 int err = pskb_trim(skb, len);
1464 BUG_ON(err);
1465 }
1466
1467 /**
1468 * skb_orphan - orphan a buffer
1469 * @skb: buffer to orphan
1470 *
1471 * If a buffer currently has an owner then we call the owner's
1472 * destructor function and make the @skb unowned. The buffer continues
1473 * to exist but is no longer charged to its former owner.
1474 */
1475 static inline void skb_orphan(struct sk_buff *skb)
1476 {
1477 if (skb->destructor)
1478 skb->destructor(skb);
1479 skb->destructor = NULL;
1480 skb->sk = NULL;
1481 }
1482
1483 /**
1484 * __skb_queue_purge - empty a list
1485 * @list: list to empty
1486 *
1487 * Delete all buffers on an &sk_buff list. Each buffer is removed from
1488 * the list and one reference dropped. This function does not take the
1489 * list lock and the caller must hold the relevant locks to use it.
1490 */
1491 extern void skb_queue_purge(struct sk_buff_head *list);
1492 static inline void __skb_queue_purge(struct sk_buff_head *list)
1493 {
1494 struct sk_buff *skb;
1495 while ((skb = __skb_dequeue(list)) != NULL)
1496 kfree_skb(skb);
1497 }
1498
1499 /**
1500 * __dev_alloc_skb - allocate an skbuff for receiving
1501 * @length: length to allocate
1502 * @gfp_mask: get_free_pages mask, passed to alloc_skb
1503 *
1504 * Allocate a new &sk_buff and assign it a usage count of one. The
1505 * buffer has unspecified headroom built in. Users should allocate
1506 * the headroom they think they need without accounting for the
1507 * built in space. The built in space is used for optimisations.
1508 *
1509 * %NULL is returned if there is no free memory.
1510 */
1511 static inline struct sk_buff *__dev_alloc_skb(unsigned int length,
1512 gfp_t gfp_mask)
1513 {
1514 struct sk_buff *skb = alloc_skb(length + NET_SKB_PAD, gfp_mask);
1515 if (likely(skb))
1516 skb_reserve(skb, NET_SKB_PAD);
1517 return skb;
1518 }
1519
1520 extern struct sk_buff *dev_alloc_skb(unsigned int length);
1521
1522 extern struct sk_buff *__netdev_alloc_skb(struct net_device *dev,
1523 unsigned int length, gfp_t gfp_mask);
1524
1525 /**
1526 * netdev_alloc_skb - allocate an skbuff for rx on a specific device
1527 * @dev: network device to receive on
1528 * @length: length to allocate
1529 *
1530 * Allocate a new &sk_buff and assign it a usage count of one. The
1531 * buffer has unspecified headroom built in. Users should allocate
1532 * the headroom they think they need without accounting for the
1533 * built in space. The built in space is used for optimisations.
1534 *
1535 * %NULL is returned if there is no free memory. Although this function
1536 * allocates memory it can be called from an interrupt.
1537 */
1538 static inline struct sk_buff *netdev_alloc_skb(struct net_device *dev,
1539 unsigned int length)
1540 {
1541 return __netdev_alloc_skb(dev, length, GFP_ATOMIC);
1542 }
1543
1544 static inline struct sk_buff *netdev_alloc_skb_ip_align(struct net_device *dev,
1545 unsigned int length)
1546 {
1547 struct sk_buff *skb = netdev_alloc_skb(dev, length + NET_IP_ALIGN);
1548
1549 if (NET_IP_ALIGN && skb)
1550 skb_reserve(skb, NET_IP_ALIGN);
1551 return skb;
1552 }
1553
1554 extern struct page *__netdev_alloc_page(struct net_device *dev, gfp_t gfp_mask);
1555
1556 /**
1557 * netdev_alloc_page - allocate a page for ps-rx on a specific device
1558 * @dev: network device to receive on
1559 *
1560 * Allocate a new page node local to the specified device.
1561 *
1562 * %NULL is returned if there is no free memory.
1563 */
1564 static inline struct page *netdev_alloc_page(struct net_device *dev)
1565 {
1566 return __netdev_alloc_page(dev, GFP_ATOMIC);
1567 }
1568
1569 static inline void netdev_free_page(struct net_device *dev, struct page *page)
1570 {
1571 __free_page(page);
1572 }
1573
1574 /**
1575 * skb_clone_writable - is the header of a clone writable
1576 * @skb: buffer to check
1577 * @len: length up to which to write
1578 *
1579 * Returns true if modifying the header part of the cloned buffer
1580 * does not requires the data to be copied.
1581 */
1582 static inline int skb_clone_writable(struct sk_buff *skb, unsigned int len)
1583 {
1584 return !skb_header_cloned(skb) &&
1585 skb_headroom(skb) + len <= skb->hdr_len;
1586 }
1587
1588 static inline int __skb_cow(struct sk_buff *skb, unsigned int headroom,
1589 int cloned)
1590 {
1591 int delta = 0;
1592
1593 if (headroom < NET_SKB_PAD)
1594 headroom = NET_SKB_PAD;
1595 if (headroom > skb_headroom(skb))
1596 delta = headroom - skb_headroom(skb);
1597
1598 if (delta || cloned)
1599 return pskb_expand_head(skb, ALIGN(delta, NET_SKB_PAD), 0,
1600 GFP_ATOMIC);
1601 return 0;
1602 }
1603
1604 /**
1605 * skb_cow - copy header of skb when it is required
1606 * @skb: buffer to cow
1607 * @headroom: needed headroom
1608 *
1609 * If the skb passed lacks sufficient headroom or its data part
1610 * is shared, data is reallocated. If reallocation fails, an error
1611 * is returned and original skb is not changed.
1612 *
1613 * The result is skb with writable area skb->head...skb->tail
1614 * and at least @headroom of space at head.
1615 */
1616 static inline int skb_cow(struct sk_buff *skb, unsigned int headroom)
1617 {
1618 return __skb_cow(skb, headroom, skb_cloned(skb));
1619 }
1620
1621 /**
1622 * skb_cow_head - skb_cow but only making the head writable
1623 * @skb: buffer to cow
1624 * @headroom: needed headroom
1625 *
1626 * This function is identical to skb_cow except that we replace the
1627 * skb_cloned check by skb_header_cloned. It should be used when
1628 * you only need to push on some header and do not need to modify
1629 * the data.
1630 */
1631 static inline int skb_cow_head(struct sk_buff *skb, unsigned int headroom)
1632 {
1633 return __skb_cow(skb, headroom, skb_header_cloned(skb));
1634 }
1635
1636 /**
1637 * skb_padto - pad an skbuff up to a minimal size
1638 * @skb: buffer to pad
1639 * @len: minimal length
1640 *
1641 * Pads up a buffer to ensure the trailing bytes exist and are
1642 * blanked. If the buffer already contains sufficient data it
1643 * is untouched. Otherwise it is extended. Returns zero on
1644 * success. The skb is freed on error.
1645 */
1646
1647 static inline int skb_padto(struct sk_buff *skb, unsigned int len)
1648 {
1649 unsigned int size = skb->len;
1650 if (likely(size >= len))
1651 return 0;
1652 return skb_pad(skb, len - size);
1653 }
1654
1655 static inline int skb_add_data(struct sk_buff *skb,
1656 char __user *from, int copy)
1657 {
1658 const int off = skb->len;
1659
1660 if (skb->ip_summed == CHECKSUM_NONE) {
1661 int err = 0;
1662 __wsum csum = csum_and_copy_from_user(from, skb_put(skb, copy),
1663 copy, 0, &err);
1664 if (!err) {
1665 skb->csum = csum_block_add(skb->csum, csum, off);
1666 return 0;
1667 }
1668 } else if (!copy_from_user(skb_put(skb, copy), from, copy))
1669 return 0;
1670
1671 __skb_trim(skb, off);
1672 return -EFAULT;
1673 }
1674
1675 static inline int skb_can_coalesce(struct sk_buff *skb, int i,
1676 struct page *page, int off)
1677 {
1678 if (i) {
1679 struct skb_frag_struct *frag = &skb_shinfo(skb)->frags[i - 1];
1680
1681 return page == frag->page &&
1682 off == frag->page_offset + frag->size;
1683 }
1684 return 0;
1685 }
1686
1687 static inline int __skb_linearize(struct sk_buff *skb)
1688 {
1689 return __pskb_pull_tail(skb, skb->data_len) ? 0 : -ENOMEM;
1690 }
1691
1692 /**
1693 * skb_linearize - convert paged skb to linear one
1694 * @skb: buffer to linarize
1695 *
1696 * If there is no free memory -ENOMEM is returned, otherwise zero
1697 * is returned and the old skb data released.
1698 */
1699 static inline int skb_linearize(struct sk_buff *skb)
1700 {
1701 return skb_is_nonlinear(skb) ? __skb_linearize(skb) : 0;
1702 }
1703
1704 /**
1705 * skb_linearize_cow - make sure skb is linear and writable
1706 * @skb: buffer to process
1707 *
1708 * If there is no free memory -ENOMEM is returned, otherwise zero
1709 * is returned and the old skb data released.
1710 */
1711 static inline int skb_linearize_cow(struct sk_buff *skb)
1712 {
1713 return skb_is_nonlinear(skb) || skb_cloned(skb) ?
1714 __skb_linearize(skb) : 0;
1715 }
1716
1717 /**
1718 * skb_postpull_rcsum - update checksum for received skb after pull
1719 * @skb: buffer to update
1720 * @start: start of data before pull
1721 * @len: length of data pulled
1722 *
1723 * After doing a pull on a received packet, you need to call this to
1724 * update the CHECKSUM_COMPLETE checksum, or set ip_summed to
1725 * CHECKSUM_NONE so that it can be recomputed from scratch.
1726 */
1727
1728 static inline void skb_postpull_rcsum(struct sk_buff *skb,
1729 const void *start, unsigned int len)
1730 {
1731 if (skb->ip_summed == CHECKSUM_COMPLETE)
1732 skb->csum = csum_sub(skb->csum, csum_partial(start, len, 0));
1733 }
1734
1735 unsigned char *skb_pull_rcsum(struct sk_buff *skb, unsigned int len);
1736
1737 /**
1738 * pskb_trim_rcsum - trim received skb and update checksum
1739 * @skb: buffer to trim
1740 * @len: new length
1741 *
1742 * This is exactly the same as pskb_trim except that it ensures the
1743 * checksum of received packets are still valid after the operation.
1744 */
1745
1746 static inline int pskb_trim_rcsum(struct sk_buff *skb, unsigned int len)
1747 {
1748 if (likely(len >= skb->len))
1749 return 0;
1750 if (skb->ip_summed == CHECKSUM_COMPLETE)
1751 skb->ip_summed = CHECKSUM_NONE;
1752 return __pskb_trim(skb, len);
1753 }
1754
1755 #define skb_queue_walk(queue, skb) \
1756 for (skb = (queue)->next; \
1757 prefetch(skb->next), (skb != (struct sk_buff *)(queue)); \
1758 skb = skb->next)
1759
1760 #define skb_queue_walk_safe(queue, skb, tmp) \
1761 for (skb = (queue)->next, tmp = skb->next; \
1762 skb != (struct sk_buff *)(queue); \
1763 skb = tmp, tmp = skb->next)
1764
1765 #define skb_queue_walk_from(queue, skb) \
1766 for (; prefetch(skb->next), (skb != (struct sk_buff *)(queue)); \
1767 skb = skb->next)
1768
1769 #define skb_queue_walk_from_safe(queue, skb, tmp) \
1770 for (tmp = skb->next; \
1771 skb != (struct sk_buff *)(queue); \
1772 skb = tmp, tmp = skb->next)
1773
1774 #define skb_queue_reverse_walk(queue, skb) \
1775 for (skb = (queue)->prev; \
1776 prefetch(skb->prev), (skb != (struct sk_buff *)(queue)); \
1777 skb = skb->prev)
1778
1779
1780 static inline bool skb_has_frags(const struct sk_buff *skb)
1781 {
1782 return skb_shinfo(skb)->frag_list != NULL;
1783 }
1784
1785 static inline void skb_frag_list_init(struct sk_buff *skb)
1786 {
1787 skb_shinfo(skb)->frag_list = NULL;
1788 }
1789
1790 static inline void skb_frag_add_head(struct sk_buff *skb, struct sk_buff *frag)
1791 {
1792 frag->next = skb_shinfo(skb)->frag_list;
1793 skb_shinfo(skb)->frag_list = frag;
1794 }
1795
1796 #define skb_walk_frags(skb, iter) \
1797 for (iter = skb_shinfo(skb)->frag_list; iter; iter = iter->next)
1798
1799 extern struct sk_buff *__skb_recv_datagram(struct sock *sk, unsigned flags,
1800 int *peeked, int *err);
1801 extern struct sk_buff *skb_recv_datagram(struct sock *sk, unsigned flags,
1802 int noblock, int *err);
1803 extern unsigned int datagram_poll(struct file *file, struct socket *sock,
1804 struct poll_table_struct *wait);
1805 extern int skb_copy_datagram_iovec(const struct sk_buff *from,
1806 int offset, struct iovec *to,
1807 int size);
1808 extern int skb_copy_and_csum_datagram_iovec(struct sk_buff *skb,
1809 int hlen,
1810 struct iovec *iov);
1811 extern int skb_copy_datagram_from_iovec(struct sk_buff *skb,
1812 int offset,
1813 const struct iovec *from,
1814 int from_offset,
1815 int len);
1816 extern int skb_copy_datagram_const_iovec(const struct sk_buff *from,
1817 int offset,
1818 const struct iovec *to,
1819 int to_offset,
1820 int size);
1821 extern void skb_free_datagram(struct sock *sk, struct sk_buff *skb);
1822 extern void skb_free_datagram_locked(struct sock *sk,
1823 struct sk_buff *skb);
1824 extern int skb_kill_datagram(struct sock *sk, struct sk_buff *skb,
1825 unsigned int flags);
1826 extern __wsum skb_checksum(const struct sk_buff *skb, int offset,
1827 int len, __wsum csum);
1828 extern int skb_copy_bits(const struct sk_buff *skb, int offset,
1829 void *to, int len);
1830 extern int skb_store_bits(struct sk_buff *skb, int offset,
1831 const void *from, int len);
1832 extern __wsum skb_copy_and_csum_bits(const struct sk_buff *skb,
1833 int offset, u8 *to, int len,
1834 __wsum csum);
1835 extern int skb_splice_bits(struct sk_buff *skb,
1836 unsigned int offset,
1837 struct pipe_inode_info *pipe,
1838 unsigned int len,
1839 unsigned int flags);
1840 extern void skb_copy_and_csum_dev(const struct sk_buff *skb, u8 *to);
1841 extern void skb_split(struct sk_buff *skb,
1842 struct sk_buff *skb1, const u32 len);
1843 extern int skb_shift(struct sk_buff *tgt, struct sk_buff *skb,
1844 int shiftlen);
1845
1846 extern struct sk_buff *skb_segment(struct sk_buff *skb, int features);
1847
1848 static inline void *skb_header_pointer(const struct sk_buff *skb, int offset,
1849 int len, void *buffer)
1850 {
1851 int hlen = skb_headlen(skb);
1852
1853 if (hlen - offset >= len)
1854 return skb->data + offset;
1855
1856 if (skb_copy_bits(skb, offset, buffer, len) < 0)
1857 return NULL;
1858
1859 return buffer;
1860 }
1861
1862 static inline void skb_copy_from_linear_data(const struct sk_buff *skb,
1863 void *to,
1864 const unsigned int len)
1865 {
1866 memcpy(to, skb->data, len);
1867 }
1868
1869 static inline void skb_copy_from_linear_data_offset(const struct sk_buff *skb,
1870 const int offset, void *to,
1871 const unsigned int len)
1872 {
1873 memcpy(to, skb->data + offset, len);
1874 }
1875
1876 static inline void skb_copy_to_linear_data(struct sk_buff *skb,
1877 const void *from,
1878 const unsigned int len)
1879 {
1880 memcpy(skb->data, from, len);
1881 }
1882
1883 static inline void skb_copy_to_linear_data_offset(struct sk_buff *skb,
1884 const int offset,
1885 const void *from,
1886 const unsigned int len)
1887 {
1888 memcpy(skb->data + offset, from, len);
1889 }
1890
1891 extern void skb_init(void);
1892
1893 static inline ktime_t skb_get_ktime(const struct sk_buff *skb)
1894 {
1895 return skb->tstamp;
1896 }
1897
1898 /**
1899 * skb_get_timestamp - get timestamp from a skb
1900 * @skb: skb to get stamp from
1901 * @stamp: pointer to struct timeval to store stamp in
1902 *
1903 * Timestamps are stored in the skb as offsets to a base timestamp.
1904 * This function converts the offset back to a struct timeval and stores
1905 * it in stamp.
1906 */
1907 static inline void skb_get_timestamp(const struct sk_buff *skb,
1908 struct timeval *stamp)
1909 {
1910 *stamp = ktime_to_timeval(skb->tstamp);
1911 }
1912
1913 static inline void skb_get_timestampns(const struct sk_buff *skb,
1914 struct timespec *stamp)
1915 {
1916 *stamp = ktime_to_timespec(skb->tstamp);
1917 }
1918
1919 static inline void __net_timestamp(struct sk_buff *skb)
1920 {
1921 skb->tstamp = ktime_get_real();
1922 }
1923
1924 static inline ktime_t net_timedelta(ktime_t t)
1925 {
1926 return ktime_sub(ktime_get_real(), t);
1927 }
1928
1929 static inline ktime_t net_invalid_timestamp(void)
1930 {
1931 return ktime_set(0, 0);
1932 }
1933
1934 /**
1935 * skb_tstamp_tx - queue clone of skb with send time stamps
1936 * @orig_skb: the original outgoing packet
1937 * @hwtstamps: hardware time stamps, may be NULL if not available
1938 *
1939 * If the skb has a socket associated, then this function clones the
1940 * skb (thus sharing the actual data and optional structures), stores
1941 * the optional hardware time stamping information (if non NULL) or
1942 * generates a software time stamp (otherwise), then queues the clone
1943 * to the error queue of the socket. Errors are silently ignored.
1944 */
1945 extern void skb_tstamp_tx(struct sk_buff *orig_skb,
1946 struct skb_shared_hwtstamps *hwtstamps);
1947
1948 extern __sum16 __skb_checksum_complete_head(struct sk_buff *skb, int len);
1949 extern __sum16 __skb_checksum_complete(struct sk_buff *skb);
1950
1951 static inline int skb_csum_unnecessary(const struct sk_buff *skb)
1952 {
1953 return skb->ip_summed & CHECKSUM_UNNECESSARY;
1954 }
1955
1956 /**
1957 * skb_checksum_complete - Calculate checksum of an entire packet
1958 * @skb: packet to process
1959 *
1960 * This function calculates the checksum over the entire packet plus
1961 * the value of skb->csum. The latter can be used to supply the
1962 * checksum of a pseudo header as used by TCP/UDP. It returns the
1963 * checksum.
1964 *
1965 * For protocols that contain complete checksums such as ICMP/TCP/UDP,
1966 * this function can be used to verify that checksum on received
1967 * packets. In that case the function should return zero if the
1968 * checksum is correct. In particular, this function will return zero
1969 * if skb->ip_summed is CHECKSUM_UNNECESSARY which indicates that the
1970 * hardware has already verified the correctness of the checksum.
1971 */
1972 static inline __sum16 skb_checksum_complete(struct sk_buff *skb)
1973 {
1974 return skb_csum_unnecessary(skb) ?
1975 0 : __skb_checksum_complete(skb);
1976 }
1977
1978 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
1979 extern void nf_conntrack_destroy(struct nf_conntrack *nfct);
1980 static inline void nf_conntrack_put(struct nf_conntrack *nfct)
1981 {
1982 if (nfct && atomic_dec_and_test(&nfct->use))
1983 nf_conntrack_destroy(nfct);
1984 }
1985 static inline void nf_conntrack_get(struct nf_conntrack *nfct)
1986 {
1987 if (nfct)
1988 atomic_inc(&nfct->use);
1989 }
1990 static inline void nf_conntrack_get_reasm(struct sk_buff *skb)
1991 {
1992 if (skb)
1993 atomic_inc(&skb->users);
1994 }
1995 static inline void nf_conntrack_put_reasm(struct sk_buff *skb)
1996 {
1997 if (skb)
1998 kfree_skb(skb);
1999 }
2000 #endif
2001 #ifdef CONFIG_BRIDGE_NETFILTER
2002 static inline void nf_bridge_put(struct nf_bridge_info *nf_bridge)
2003 {
2004 if (nf_bridge && atomic_dec_and_test(&nf_bridge->use))
2005 kfree(nf_bridge);
2006 }
2007 static inline void nf_bridge_get(struct nf_bridge_info *nf_bridge)
2008 {
2009 if (nf_bridge)
2010 atomic_inc(&nf_bridge->use);
2011 }
2012 #endif /* CONFIG_BRIDGE_NETFILTER */
2013 static inline void nf_reset(struct sk_buff *skb)
2014 {
2015 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
2016 nf_conntrack_put(skb->nfct);
2017 skb->nfct = NULL;
2018 nf_conntrack_put_reasm(skb->nfct_reasm);
2019 skb->nfct_reasm = NULL;
2020 #endif
2021 #ifdef CONFIG_BRIDGE_NETFILTER
2022 nf_bridge_put(skb->nf_bridge);
2023 skb->nf_bridge = NULL;
2024 #endif
2025 }
2026
2027 /* Note: This doesn't put any conntrack and bridge info in dst. */
2028 static inline void __nf_copy(struct sk_buff *dst, const struct sk_buff *src)
2029 {
2030 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
2031 dst->nfct = src->nfct;
2032 nf_conntrack_get(src->nfct);
2033 dst->nfctinfo = src->nfctinfo;
2034 dst->nfct_reasm = src->nfct_reasm;
2035 nf_conntrack_get_reasm(src->nfct_reasm);
2036 #endif
2037 #ifdef CONFIG_BRIDGE_NETFILTER
2038 dst->nf_bridge = src->nf_bridge;
2039 nf_bridge_get(src->nf_bridge);
2040 #endif
2041 }
2042
2043 static inline void nf_copy(struct sk_buff *dst, const struct sk_buff *src)
2044 {
2045 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
2046 nf_conntrack_put(dst->nfct);
2047 nf_conntrack_put_reasm(dst->nfct_reasm);
2048 #endif
2049 #ifdef CONFIG_BRIDGE_NETFILTER
2050 nf_bridge_put(dst->nf_bridge);
2051 #endif
2052 __nf_copy(dst, src);
2053 }
2054
2055 #ifdef CONFIG_NETWORK_SECMARK
2056 static inline void skb_copy_secmark(struct sk_buff *to, const struct sk_buff *from)
2057 {
2058 to->secmark = from->secmark;
2059 }
2060
2061 static inline void skb_init_secmark(struct sk_buff *skb)
2062 {
2063 skb->secmark = 0;
2064 }
2065 #else
2066 static inline void skb_copy_secmark(struct sk_buff *to, const struct sk_buff *from)
2067 { }
2068
2069 static inline void skb_init_secmark(struct sk_buff *skb)
2070 { }
2071 #endif
2072
2073 static inline void skb_set_queue_mapping(struct sk_buff *skb, u16 queue_mapping)
2074 {
2075 skb->queue_mapping = queue_mapping;
2076 }
2077
2078 static inline u16 skb_get_queue_mapping(const struct sk_buff *skb)
2079 {
2080 return skb->queue_mapping;
2081 }
2082
2083 static inline void skb_copy_queue_mapping(struct sk_buff *to, const struct sk_buff *from)
2084 {
2085 to->queue_mapping = from->queue_mapping;
2086 }
2087
2088 static inline void skb_record_rx_queue(struct sk_buff *skb, u16 rx_queue)
2089 {
2090 skb->queue_mapping = rx_queue + 1;
2091 }
2092
2093 static inline u16 skb_get_rx_queue(const struct sk_buff *skb)
2094 {
2095 return skb->queue_mapping - 1;
2096 }
2097
2098 static inline bool skb_rx_queue_recorded(const struct sk_buff *skb)
2099 {
2100 return (skb->queue_mapping != 0);
2101 }
2102
2103 extern u16 skb_tx_hash(const struct net_device *dev,
2104 const struct sk_buff *skb);
2105
2106 #ifdef CONFIG_XFRM
2107 static inline struct sec_path *skb_sec_path(struct sk_buff *skb)
2108 {
2109 return skb->sp;
2110 }
2111 #else
2112 static inline struct sec_path *skb_sec_path(struct sk_buff *skb)
2113 {
2114 return NULL;
2115 }
2116 #endif
2117
2118 static inline int skb_is_gso(const struct sk_buff *skb)
2119 {
2120 return skb_shinfo(skb)->gso_size;
2121 }
2122
2123 static inline int skb_is_gso_v6(const struct sk_buff *skb)
2124 {
2125 return skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6;
2126 }
2127
2128 extern void __skb_warn_lro_forwarding(const struct sk_buff *skb);
2129
2130 static inline bool skb_warn_if_lro(const struct sk_buff *skb)
2131 {
2132 /* LRO sets gso_size but not gso_type, whereas if GSO is really
2133 * wanted then gso_type will be set. */
2134 struct skb_shared_info *shinfo = skb_shinfo(skb);
2135 if (shinfo->gso_size != 0 && unlikely(shinfo->gso_type == 0)) {
2136 __skb_warn_lro_forwarding(skb);
2137 return true;
2138 }
2139 return false;
2140 }
2141
2142 static inline void skb_forward_csum(struct sk_buff *skb)
2143 {
2144 /* Unfortunately we don't support this one. Any brave souls? */
2145 if (skb->ip_summed == CHECKSUM_COMPLETE)
2146 skb->ip_summed = CHECKSUM_NONE;
2147 }
2148
2149 bool skb_partial_csum_set(struct sk_buff *skb, u16 start, u16 off);
2150 #endif /* __KERNEL__ */
2151 #endif /* _LINUX_SKBUFF_H */