2 * Definitions for the 'struct sk_buff' memory handlers.
5 * Alan Cox, <gw4pts@gw4pts.ampr.org>
6 * Florian La Roche, <rzsfl@rz.uni-sb.de>
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.
14 #ifndef _LINUX_SKBUFF_H
15 #define _LINUX_SKBUFF_H
17 #include <linux/kernel.h>
18 #include <linux/compiler.h>
19 #include <linux/time.h>
20 #include <linux/cache.h>
22 #include <asm/atomic.h>
23 #include <asm/types.h>
24 #include <linux/spinlock.h>
25 #include <linux/net.h>
26 #include <linux/textsearch.h>
27 #include <net/checksum.h>
28 #include <linux/rcupdate.h>
29 #include <linux/dmaengine.h>
30 #include <linux/hrtimer.h>
32 /* Don't change this without changing skb_csum_unnecessary! */
33 #define CHECKSUM_NONE 0
34 #define CHECKSUM_UNNECESSARY 1
35 #define CHECKSUM_COMPLETE 2
36 #define CHECKSUM_PARTIAL 3
38 #define SKB_DATA_ALIGN(X) (((X) + (SMP_CACHE_BYTES - 1)) & \
39 ~(SMP_CACHE_BYTES - 1))
40 #define SKB_WITH_OVERHEAD(X) \
41 ((X) - SKB_DATA_ALIGN(sizeof(struct skb_shared_info)))
42 #define SKB_MAX_ORDER(X, ORDER) \
43 SKB_WITH_OVERHEAD((PAGE_SIZE << (ORDER)) - (X))
44 #define SKB_MAX_HEAD(X) (SKB_MAX_ORDER((X), 0))
45 #define SKB_MAX_ALLOC (SKB_MAX_ORDER(0, 2))
47 /* A. Checksumming of received packets by device.
49 * NONE: device failed to checksum this packet.
50 * skb->csum is undefined.
52 * UNNECESSARY: device parsed packet and wouldbe verified checksum.
53 * skb->csum is undefined.
54 * It is bad option, but, unfortunately, many of vendors do this.
55 * Apparently with secret goal to sell you new device, when you
56 * will add new protocol to your host. F.e. IPv6. 8)
58 * COMPLETE: the most generic way. Device supplied checksum of _all_
59 * the packet as seen by netif_rx in skb->csum.
60 * NOTE: Even if device supports only some protocols, but
61 * is able to produce some skb->csum, it MUST use COMPLETE,
64 * PARTIAL: identical to the case for output below. This may occur
65 * on a packet received directly from another Linux OS, e.g.,
66 * a virtualised Linux kernel on the same host. The packet can
67 * be treated in the same way as UNNECESSARY except that on
68 * output (i.e., forwarding) the checksum must be filled in
69 * by the OS or the hardware.
71 * B. Checksumming on output.
73 * NONE: skb is checksummed by protocol or csum is not required.
75 * PARTIAL: device is required to csum packet as seen by hard_start_xmit
76 * from skb->csum_start to the end and to record the checksum
77 * at skb->csum_start + skb->csum_offset.
79 * Device must show its capabilities in dev->features, set
80 * at device setup time.
81 * NETIF_F_HW_CSUM - it is clever device, it is able to checksum
83 * NETIF_F_NO_CSUM - loopback or reliable single hop media.
84 * NETIF_F_IP_CSUM - device is dumb. It is able to csum only
85 * TCP/UDP over IPv4. Sigh. Vendors like this
86 * way by an unknown reason. Though, see comment above
87 * about CHECKSUM_UNNECESSARY. 8)
88 * NETIF_F_IPV6_CSUM about as dumb as the last one but does IPv6 instead.
90 * Any questions? No questions, good. --ANK
95 struct pipe_inode_info;
97 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
103 #ifdef CONFIG_BRIDGE_NETFILTER
104 struct nf_bridge_info {
106 struct net_device *physindev;
107 struct net_device *physoutdev;
109 unsigned long data[32 / sizeof(unsigned long)];
113 struct sk_buff_head {
114 /* These two members must be first. */
115 struct sk_buff *next;
116 struct sk_buff *prev;
124 /* To allow 64K frame to be packed as single skb without frag_list */
125 #define MAX_SKB_FRAGS (65536/PAGE_SIZE + 2)
127 typedef struct skb_frag_struct skb_frag_t;
129 struct skb_frag_struct {
135 #define HAVE_HW_TIME_STAMP
138 * struct skb_shared_hwtstamps - hardware time stamps
139 * @hwtstamp: hardware time stamp transformed into duration
140 * since arbitrary point in time
141 * @syststamp: hwtstamp transformed to system time base
143 * Software time stamps generated by ktime_get_real() are stored in
144 * skb->tstamp. The relation between the different kinds of time
145 * stamps is as follows:
147 * syststamp and tstamp can be compared against each other in
148 * arbitrary combinations. The accuracy of a
149 * syststamp/tstamp/"syststamp from other device" comparison is
150 * limited by the accuracy of the transformation into system time
151 * base. This depends on the device driver and its underlying
154 * hwtstamps can only be compared against other hwtstamps from
157 * This structure is attached to packets as part of the
158 * &skb_shared_info. Use skb_hwtstamps() to get a pointer.
160 struct skb_shared_hwtstamps {
166 * struct skb_shared_tx - instructions for time stamping of outgoing packets
167 * @hardware: generate hardware time stamp
168 * @software: generate software time stamp
169 * @in_progress: device driver is going to provide
170 * hardware time stamp
172 * These flags are attached to packets as part of the
173 * &skb_shared_info. Use skb_tx() to get a pointer.
175 union skb_shared_tx {
184 /* This data is invariant across clones and lives at
185 * the end of the header data, ie. at skb->end.
187 struct skb_shared_info {
189 unsigned short nr_frags;
190 unsigned short gso_size;
191 /* Warning: this field is not always filled in (UFO)! */
192 unsigned short gso_segs;
193 unsigned short gso_type;
195 union skb_shared_tx tx_flags;
196 #ifdef CONFIG_HAS_DMA
197 unsigned int num_dma_maps;
199 struct sk_buff *frag_list;
200 struct skb_shared_hwtstamps hwtstamps;
201 skb_frag_t frags[MAX_SKB_FRAGS];
202 #ifdef CONFIG_HAS_DMA
203 dma_addr_t dma_maps[MAX_SKB_FRAGS + 1];
207 /* We divide dataref into two halves. The higher 16 bits hold references
208 * to the payload part of skb->data. The lower 16 bits hold references to
209 * the entire skb->data. A clone of a headerless skb holds the length of
210 * the header in skb->hdr_len.
212 * All users must obey the rule that the skb->data reference count must be
213 * greater than or equal to the payload reference count.
215 * Holding a reference to the payload part means that the user does not
216 * care about modifications to the header part of skb->data.
218 #define SKB_DATAREF_SHIFT 16
219 #define SKB_DATAREF_MASK ((1 << SKB_DATAREF_SHIFT) - 1)
223 SKB_FCLONE_UNAVAILABLE,
229 SKB_GSO_TCPV4 = 1 << 0,
230 SKB_GSO_UDP = 1 << 1,
232 /* This indicates the skb is from an untrusted source. */
233 SKB_GSO_DODGY = 1 << 2,
235 /* This indicates the tcp segment has CWR set. */
236 SKB_GSO_TCP_ECN = 1 << 3,
238 SKB_GSO_TCPV6 = 1 << 4,
241 #if BITS_PER_LONG > 32
242 #define NET_SKBUFF_DATA_USES_OFFSET 1
245 #ifdef NET_SKBUFF_DATA_USES_OFFSET
246 typedef unsigned int sk_buff_data_t;
248 typedef unsigned char *sk_buff_data_t;
252 * struct sk_buff - socket buffer
253 * @next: Next buffer in list
254 * @prev: Previous buffer in list
255 * @sk: Socket we are owned by
256 * @tstamp: Time we arrived
257 * @dev: Device we arrived on/are leaving by
258 * @transport_header: Transport layer header
259 * @network_header: Network layer header
260 * @mac_header: Link layer header
261 * @dst: destination entry
262 * @sp: the security path, used for xfrm
263 * @cb: Control buffer. Free for use by every layer. Put private vars here
264 * @len: Length of actual data
265 * @data_len: Data length
266 * @mac_len: Length of link layer header
267 * @hdr_len: writable header length of cloned skb
268 * @csum: Checksum (must include start/offset pair)
269 * @csum_start: Offset from skb->head where checksumming should start
270 * @csum_offset: Offset from csum_start where checksum should be stored
271 * @local_df: allow local fragmentation
272 * @cloned: Head may be cloned (check refcnt to be sure)
273 * @nohdr: Payload reference only, must not modify header
274 * @pkt_type: Packet class
275 * @fclone: skbuff clone status
276 * @ip_summed: Driver fed us an IP checksum
277 * @priority: Packet queueing priority
278 * @users: User count - see {datagram,tcp}.c
279 * @protocol: Packet protocol from driver
280 * @truesize: Buffer size
281 * @head: Head of buffer
282 * @data: Data head pointer
283 * @tail: Tail pointer
285 * @destructor: Destruct function
286 * @mark: Generic packet mark
287 * @nfct: Associated connection, if any
288 * @ipvs_property: skbuff is owned by ipvs
289 * @peeked: this packet has been seen already, so stats have been
290 * done for it, don't do them again
291 * @nf_trace: netfilter packet trace flag
292 * @nfctinfo: Relationship of this skb to the connection
293 * @nfct_reasm: netfilter conntrack re-assembly pointer
294 * @nf_bridge: Saved data about a bridged frame - see br_netfilter.c
295 * @iif: ifindex of device we arrived on
296 * @queue_mapping: Queue mapping for multiqueue devices
297 * @tc_index: Traffic control index
298 * @tc_verd: traffic control verdict
299 * @ndisc_nodetype: router type (from link layer)
300 * @do_not_encrypt: set to prevent encryption of this frame
301 * @requeue: set to indicate that the wireless core should attempt
302 * a software retry on this frame if we failed to
303 * receive an ACK for it
304 * @dma_cookie: a cookie to one of several possible DMA operations
305 * done by skb DMA functions
306 * @secmark: security marking
307 * @vlan_tci: vlan tag control information
311 /* These two members must be first. */
312 struct sk_buff *next;
313 struct sk_buff *prev;
317 struct net_device *dev;
320 struct dst_entry *dst;
321 struct rtable *rtable;
327 * This is the control buffer. It is free to use for every
328 * layer. Please put your private variables there. If you
329 * want to keep them across layers you have to do a skb_clone()
330 * first. This is owned by whoever has the skb queued ATM.
358 void (*destructor)(struct sk_buff *skb);
359 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
360 struct nf_conntrack *nfct;
361 struct sk_buff *nfct_reasm;
363 #ifdef CONFIG_BRIDGE_NETFILTER
364 struct nf_bridge_info *nf_bridge;
369 #ifdef CONFIG_NET_SCHED
370 __u16 tc_index; /* traffic control index */
371 #ifdef CONFIG_NET_CLS_ACT
372 __u16 tc_verd; /* traffic control verdict */
375 #ifdef CONFIG_IPV6_NDISC_NODETYPE
376 __u8 ndisc_nodetype:2;
378 #if defined(CONFIG_MAC80211) || defined(CONFIG_MAC80211_MODULE)
379 __u8 do_not_encrypt:1;
382 /* 0/13/14 bit hole */
384 #ifdef CONFIG_NET_DMA
385 dma_cookie_t dma_cookie;
387 #ifdef CONFIG_NETWORK_SECMARK
395 sk_buff_data_t transport_header;
396 sk_buff_data_t network_header;
397 sk_buff_data_t mac_header;
398 /* These elements must be at the end, see alloc_skb() for details. */
403 unsigned int truesize;
409 * Handling routines are only of interest to the kernel
411 #include <linux/slab.h>
413 #include <asm/system.h>
415 #ifdef CONFIG_HAS_DMA
416 #include <linux/dma-mapping.h>
417 extern int skb_dma_map(struct device *dev, struct sk_buff *skb,
418 enum dma_data_direction dir);
419 extern void skb_dma_unmap(struct device *dev, struct sk_buff *skb,
420 enum dma_data_direction dir);
423 extern void kfree_skb(struct sk_buff *skb);
424 extern void __kfree_skb(struct sk_buff *skb);
425 extern struct sk_buff *__alloc_skb(unsigned int size,
426 gfp_t priority, int fclone, int node);
427 static inline struct sk_buff *alloc_skb(unsigned int size,
430 return __alloc_skb(size, priority, 0, -1);
433 static inline struct sk_buff *alloc_skb_fclone(unsigned int size,
436 return __alloc_skb(size, priority, 1, -1);
439 extern int skb_recycle_check(struct sk_buff *skb, int skb_size);
441 extern struct sk_buff *skb_morph(struct sk_buff *dst, struct sk_buff *src);
442 extern struct sk_buff *skb_clone(struct sk_buff *skb,
444 extern struct sk_buff *skb_copy(const struct sk_buff *skb,
446 extern struct sk_buff *pskb_copy(struct sk_buff *skb,
448 extern int pskb_expand_head(struct sk_buff *skb,
449 int nhead, int ntail,
451 extern struct sk_buff *skb_realloc_headroom(struct sk_buff *skb,
452 unsigned int headroom);
453 extern struct sk_buff *skb_copy_expand(const struct sk_buff *skb,
454 int newheadroom, int newtailroom,
456 extern int skb_to_sgvec(struct sk_buff *skb,
457 struct scatterlist *sg, int offset,
459 extern int skb_cow_data(struct sk_buff *skb, int tailbits,
460 struct sk_buff **trailer);
461 extern int skb_pad(struct sk_buff *skb, int pad);
462 #define dev_kfree_skb(a) kfree_skb(a)
463 extern void skb_over_panic(struct sk_buff *skb, int len,
465 extern void skb_under_panic(struct sk_buff *skb, int len,
468 extern int skb_append_datato_frags(struct sock *sk, struct sk_buff *skb,
469 int getfrag(void *from, char *to, int offset,
470 int len,int odd, struct sk_buff *skb),
471 void *from, int length);
478 __u32 stepped_offset;
479 struct sk_buff *root_skb;
480 struct sk_buff *cur_skb;
484 extern void skb_prepare_seq_read(struct sk_buff *skb,
485 unsigned int from, unsigned int to,
486 struct skb_seq_state *st);
487 extern unsigned int skb_seq_read(unsigned int consumed, const u8 **data,
488 struct skb_seq_state *st);
489 extern void skb_abort_seq_read(struct skb_seq_state *st);
491 extern unsigned int skb_find_text(struct sk_buff *skb, unsigned int from,
492 unsigned int to, struct ts_config *config,
493 struct ts_state *state);
495 #ifdef NET_SKBUFF_DATA_USES_OFFSET
496 static inline unsigned char *skb_end_pointer(const struct sk_buff *skb)
498 return skb->head + skb->end;
501 static inline unsigned char *skb_end_pointer(const struct sk_buff *skb)
508 #define skb_shinfo(SKB) ((struct skb_shared_info *)(skb_end_pointer(SKB)))
510 static inline struct skb_shared_hwtstamps *skb_hwtstamps(struct sk_buff *skb)
512 return &skb_shinfo(skb)->hwtstamps;
515 static inline union skb_shared_tx *skb_tx(struct sk_buff *skb)
517 return &skb_shinfo(skb)->tx_flags;
521 * skb_queue_empty - check if a queue is empty
524 * Returns true if the queue is empty, false otherwise.
526 static inline int skb_queue_empty(const struct sk_buff_head *list)
528 return list->next == (struct sk_buff *)list;
532 * skb_queue_is_last - check if skb is the last entry in the queue
536 * Returns true if @skb is the last buffer on the list.
538 static inline bool skb_queue_is_last(const struct sk_buff_head *list,
539 const struct sk_buff *skb)
541 return (skb->next == (struct sk_buff *) list);
545 * skb_queue_is_first - check if skb is the first entry in the queue
549 * Returns true if @skb is the first buffer on the list.
551 static inline bool skb_queue_is_first(const struct sk_buff_head *list,
552 const struct sk_buff *skb)
554 return (skb->prev == (struct sk_buff *) list);
558 * skb_queue_next - return the next packet in the queue
560 * @skb: current buffer
562 * Return the next packet in @list after @skb. It is only valid to
563 * call this if skb_queue_is_last() evaluates to false.
565 static inline struct sk_buff *skb_queue_next(const struct sk_buff_head *list,
566 const struct sk_buff *skb)
568 /* This BUG_ON may seem severe, but if we just return then we
569 * are going to dereference garbage.
571 BUG_ON(skb_queue_is_last(list, skb));
576 * skb_queue_prev - return the prev packet in the queue
578 * @skb: current buffer
580 * Return the prev packet in @list before @skb. It is only valid to
581 * call this if skb_queue_is_first() evaluates to false.
583 static inline struct sk_buff *skb_queue_prev(const struct sk_buff_head *list,
584 const struct sk_buff *skb)
586 /* This BUG_ON may seem severe, but if we just return then we
587 * are going to dereference garbage.
589 BUG_ON(skb_queue_is_first(list, skb));
594 * skb_get - reference buffer
595 * @skb: buffer to reference
597 * Makes another reference to a socket buffer and returns a pointer
600 static inline struct sk_buff *skb_get(struct sk_buff *skb)
602 atomic_inc(&skb->users);
607 * If users == 1, we are the only owner and are can avoid redundant
612 * skb_cloned - is the buffer a clone
613 * @skb: buffer to check
615 * Returns true if the buffer was generated with skb_clone() and is
616 * one of multiple shared copies of the buffer. Cloned buffers are
617 * shared data so must not be written to under normal circumstances.
619 static inline int skb_cloned(const struct sk_buff *skb)
621 return skb->cloned &&
622 (atomic_read(&skb_shinfo(skb)->dataref) & SKB_DATAREF_MASK) != 1;
626 * skb_header_cloned - is the header a clone
627 * @skb: buffer to check
629 * Returns true if modifying the header part of the buffer requires
630 * the data to be copied.
632 static inline int skb_header_cloned(const struct sk_buff *skb)
639 dataref = atomic_read(&skb_shinfo(skb)->dataref);
640 dataref = (dataref & SKB_DATAREF_MASK) - (dataref >> SKB_DATAREF_SHIFT);
645 * skb_header_release - release reference to header
646 * @skb: buffer to operate on
648 * Drop a reference to the header part of the buffer. This is done
649 * by acquiring a payload reference. You must not read from the header
650 * part of skb->data after this.
652 static inline void skb_header_release(struct sk_buff *skb)
656 atomic_add(1 << SKB_DATAREF_SHIFT, &skb_shinfo(skb)->dataref);
660 * skb_shared - is the buffer shared
661 * @skb: buffer to check
663 * Returns true if more than one person has a reference to this
666 static inline int skb_shared(const struct sk_buff *skb)
668 return atomic_read(&skb->users) != 1;
672 * skb_share_check - check if buffer is shared and if so clone it
673 * @skb: buffer to check
674 * @pri: priority for memory allocation
676 * If the buffer is shared the buffer is cloned and the old copy
677 * drops a reference. A new clone with a single reference is returned.
678 * If the buffer is not shared the original buffer is returned. When
679 * being called from interrupt status or with spinlocks held pri must
682 * NULL is returned on a memory allocation failure.
684 static inline struct sk_buff *skb_share_check(struct sk_buff *skb,
687 might_sleep_if(pri & __GFP_WAIT);
688 if (skb_shared(skb)) {
689 struct sk_buff *nskb = skb_clone(skb, pri);
697 * Copy shared buffers into a new sk_buff. We effectively do COW on
698 * packets to handle cases where we have a local reader and forward
699 * and a couple of other messy ones. The normal one is tcpdumping
700 * a packet thats being forwarded.
704 * skb_unshare - make a copy of a shared buffer
705 * @skb: buffer to check
706 * @pri: priority for memory allocation
708 * If the socket buffer is a clone then this function creates a new
709 * copy of the data, drops a reference count on the old copy and returns
710 * the new copy with the reference count at 1. If the buffer is not a clone
711 * the original buffer is returned. When called with a spinlock held or
712 * from interrupt state @pri must be %GFP_ATOMIC
714 * %NULL is returned on a memory allocation failure.
716 static inline struct sk_buff *skb_unshare(struct sk_buff *skb,
719 might_sleep_if(pri & __GFP_WAIT);
720 if (skb_cloned(skb)) {
721 struct sk_buff *nskb = skb_copy(skb, pri);
722 kfree_skb(skb); /* Free our shared copy */
730 * @list_: list to peek at
732 * Peek an &sk_buff. Unlike most other operations you _MUST_
733 * be careful with this one. A peek leaves the buffer on the
734 * list and someone else may run off with it. You must hold
735 * the appropriate locks or have a private queue to do this.
737 * Returns %NULL for an empty list or a pointer to the head element.
738 * The reference count is not incremented and the reference is therefore
739 * volatile. Use with caution.
741 static inline struct sk_buff *skb_peek(struct sk_buff_head *list_)
743 struct sk_buff *list = ((struct sk_buff *)list_)->next;
744 if (list == (struct sk_buff *)list_)
751 * @list_: list to peek at
753 * Peek an &sk_buff. Unlike most other operations you _MUST_
754 * be careful with this one. A peek leaves the buffer on the
755 * list and someone else may run off with it. You must hold
756 * the appropriate locks or have a private queue to do this.
758 * Returns %NULL for an empty list or a pointer to the tail element.
759 * The reference count is not incremented and the reference is therefore
760 * volatile. Use with caution.
762 static inline struct sk_buff *skb_peek_tail(struct sk_buff_head *list_)
764 struct sk_buff *list = ((struct sk_buff *)list_)->prev;
765 if (list == (struct sk_buff *)list_)
771 * skb_queue_len - get queue length
772 * @list_: list to measure
774 * Return the length of an &sk_buff queue.
776 static inline __u32 skb_queue_len(const struct sk_buff_head *list_)
782 * __skb_queue_head_init - initialize non-spinlock portions of sk_buff_head
783 * @list: queue to initialize
785 * This initializes only the list and queue length aspects of
786 * an sk_buff_head object. This allows to initialize the list
787 * aspects of an sk_buff_head without reinitializing things like
788 * the spinlock. It can also be used for on-stack sk_buff_head
789 * objects where the spinlock is known to not be used.
791 static inline void __skb_queue_head_init(struct sk_buff_head *list)
793 list->prev = list->next = (struct sk_buff *)list;
798 * This function creates a split out lock class for each invocation;
799 * this is needed for now since a whole lot of users of the skb-queue
800 * infrastructure in drivers have different locking usage (in hardirq)
801 * than the networking core (in softirq only). In the long run either the
802 * network layer or drivers should need annotation to consolidate the
803 * main types of usage into 3 classes.
805 static inline void skb_queue_head_init(struct sk_buff_head *list)
807 spin_lock_init(&list->lock);
808 __skb_queue_head_init(list);
811 static inline void skb_queue_head_init_class(struct sk_buff_head *list,
812 struct lock_class_key *class)
814 skb_queue_head_init(list);
815 lockdep_set_class(&list->lock, class);
819 * Insert an sk_buff on a list.
821 * The "__skb_xxxx()" functions are the non-atomic ones that
822 * can only be called with interrupts disabled.
824 extern void skb_insert(struct sk_buff *old, struct sk_buff *newsk, struct sk_buff_head *list);
825 static inline void __skb_insert(struct sk_buff *newsk,
826 struct sk_buff *prev, struct sk_buff *next,
827 struct sk_buff_head *list)
831 next->prev = prev->next = newsk;
835 static inline void __skb_queue_splice(const struct sk_buff_head *list,
836 struct sk_buff *prev,
837 struct sk_buff *next)
839 struct sk_buff *first = list->next;
840 struct sk_buff *last = list->prev;
850 * skb_queue_splice - join two skb lists, this is designed for stacks
851 * @list: the new list to add
852 * @head: the place to add it in the first list
854 static inline void skb_queue_splice(const struct sk_buff_head *list,
855 struct sk_buff_head *head)
857 if (!skb_queue_empty(list)) {
858 __skb_queue_splice(list, (struct sk_buff *) head, head->next);
859 head->qlen += list->qlen;
864 * skb_queue_splice - join two skb lists and reinitialise the emptied list
865 * @list: the new list to add
866 * @head: the place to add it in the first list
868 * The list at @list is reinitialised
870 static inline void skb_queue_splice_init(struct sk_buff_head *list,
871 struct sk_buff_head *head)
873 if (!skb_queue_empty(list)) {
874 __skb_queue_splice(list, (struct sk_buff *) head, head->next);
875 head->qlen += list->qlen;
876 __skb_queue_head_init(list);
881 * skb_queue_splice_tail - join two skb lists, each list being a queue
882 * @list: the new list to add
883 * @head: the place to add it in the first list
885 static inline void skb_queue_splice_tail(const struct sk_buff_head *list,
886 struct sk_buff_head *head)
888 if (!skb_queue_empty(list)) {
889 __skb_queue_splice(list, head->prev, (struct sk_buff *) head);
890 head->qlen += list->qlen;
895 * skb_queue_splice_tail - join two skb lists and reinitialise the emptied list
896 * @list: the new list to add
897 * @head: the place to add it in the first list
899 * Each of the lists is a queue.
900 * The list at @list is reinitialised
902 static inline void skb_queue_splice_tail_init(struct sk_buff_head *list,
903 struct sk_buff_head *head)
905 if (!skb_queue_empty(list)) {
906 __skb_queue_splice(list, head->prev, (struct sk_buff *) head);
907 head->qlen += list->qlen;
908 __skb_queue_head_init(list);
913 * __skb_queue_after - queue a buffer at the list head
915 * @prev: place after this buffer
916 * @newsk: buffer to queue
918 * Queue a buffer int the middle of a list. This function takes no locks
919 * and you must therefore hold required locks before calling it.
921 * A buffer cannot be placed on two lists at the same time.
923 static inline void __skb_queue_after(struct sk_buff_head *list,
924 struct sk_buff *prev,
925 struct sk_buff *newsk)
927 __skb_insert(newsk, prev, prev->next, list);
930 extern void skb_append(struct sk_buff *old, struct sk_buff *newsk,
931 struct sk_buff_head *list);
933 static inline void __skb_queue_before(struct sk_buff_head *list,
934 struct sk_buff *next,
935 struct sk_buff *newsk)
937 __skb_insert(newsk, next->prev, next, list);
941 * __skb_queue_head - queue a buffer at the list head
943 * @newsk: buffer to queue
945 * Queue a buffer at the start of a list. This function takes no locks
946 * and you must therefore hold required locks before calling it.
948 * A buffer cannot be placed on two lists at the same time.
950 extern void skb_queue_head(struct sk_buff_head *list, struct sk_buff *newsk);
951 static inline void __skb_queue_head(struct sk_buff_head *list,
952 struct sk_buff *newsk)
954 __skb_queue_after(list, (struct sk_buff *)list, newsk);
958 * __skb_queue_tail - queue a buffer at the list tail
960 * @newsk: buffer to queue
962 * Queue a buffer at the end of a list. This function takes no locks
963 * and you must therefore hold required locks before calling it.
965 * A buffer cannot be placed on two lists at the same time.
967 extern void skb_queue_tail(struct sk_buff_head *list, struct sk_buff *newsk);
968 static inline void __skb_queue_tail(struct sk_buff_head *list,
969 struct sk_buff *newsk)
971 __skb_queue_before(list, (struct sk_buff *)list, newsk);
975 * remove sk_buff from list. _Must_ be called atomically, and with
978 extern void skb_unlink(struct sk_buff *skb, struct sk_buff_head *list);
979 static inline void __skb_unlink(struct sk_buff *skb, struct sk_buff_head *list)
981 struct sk_buff *next, *prev;
986 skb->next = skb->prev = NULL;
992 * __skb_dequeue - remove from the head of the queue
993 * @list: list to dequeue from
995 * Remove the head of the list. This function does not take any locks
996 * so must be used with appropriate locks held only. The head item is
997 * returned or %NULL if the list is empty.
999 extern struct sk_buff *skb_dequeue(struct sk_buff_head *list);
1000 static inline struct sk_buff *__skb_dequeue(struct sk_buff_head *list)
1002 struct sk_buff *skb = skb_peek(list);
1004 __skb_unlink(skb, list);
1009 * __skb_dequeue_tail - remove from the tail of the queue
1010 * @list: list to dequeue from
1012 * Remove the tail of the list. This function does not take any locks
1013 * so must be used with appropriate locks held only. The tail item is
1014 * returned or %NULL if the list is empty.
1016 extern struct sk_buff *skb_dequeue_tail(struct sk_buff_head *list);
1017 static inline struct sk_buff *__skb_dequeue_tail(struct sk_buff_head *list)
1019 struct sk_buff *skb = skb_peek_tail(list);
1021 __skb_unlink(skb, list);
1026 static inline int skb_is_nonlinear(const struct sk_buff *skb)
1028 return skb->data_len;
1031 static inline unsigned int skb_headlen(const struct sk_buff *skb)
1033 return skb->len - skb->data_len;
1036 static inline int skb_pagelen(const struct sk_buff *skb)
1040 for (i = (int)skb_shinfo(skb)->nr_frags - 1; i >= 0; i--)
1041 len += skb_shinfo(skb)->frags[i].size;
1042 return len + skb_headlen(skb);
1045 static inline void skb_fill_page_desc(struct sk_buff *skb, int i,
1046 struct page *page, int off, int size)
1048 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
1051 frag->page_offset = off;
1053 skb_shinfo(skb)->nr_frags = i + 1;
1056 extern void skb_add_rx_frag(struct sk_buff *skb, int i, struct page *page,
1059 #define SKB_PAGE_ASSERT(skb) BUG_ON(skb_shinfo(skb)->nr_frags)
1060 #define SKB_FRAG_ASSERT(skb) BUG_ON(skb_shinfo(skb)->frag_list)
1061 #define SKB_LINEAR_ASSERT(skb) BUG_ON(skb_is_nonlinear(skb))
1063 #ifdef NET_SKBUFF_DATA_USES_OFFSET
1064 static inline unsigned char *skb_tail_pointer(const struct sk_buff *skb)
1066 return skb->head + skb->tail;
1069 static inline void skb_reset_tail_pointer(struct sk_buff *skb)
1071 skb->tail = skb->data - skb->head;
1074 static inline void skb_set_tail_pointer(struct sk_buff *skb, const int offset)
1076 skb_reset_tail_pointer(skb);
1077 skb->tail += offset;
1079 #else /* NET_SKBUFF_DATA_USES_OFFSET */
1080 static inline unsigned char *skb_tail_pointer(const struct sk_buff *skb)
1085 static inline void skb_reset_tail_pointer(struct sk_buff *skb)
1087 skb->tail = skb->data;
1090 static inline void skb_set_tail_pointer(struct sk_buff *skb, const int offset)
1092 skb->tail = skb->data + offset;
1095 #endif /* NET_SKBUFF_DATA_USES_OFFSET */
1098 * Add data to an sk_buff
1100 extern unsigned char *skb_put(struct sk_buff *skb, unsigned int len);
1101 static inline unsigned char *__skb_put(struct sk_buff *skb, unsigned int len)
1103 unsigned char *tmp = skb_tail_pointer(skb);
1104 SKB_LINEAR_ASSERT(skb);
1110 extern unsigned char *skb_push(struct sk_buff *skb, unsigned int len);
1111 static inline unsigned char *__skb_push(struct sk_buff *skb, unsigned int len)
1118 extern unsigned char *skb_pull(struct sk_buff *skb, unsigned int len);
1119 static inline unsigned char *__skb_pull(struct sk_buff *skb, unsigned int len)
1122 BUG_ON(skb->len < skb->data_len);
1123 return skb->data += len;
1126 extern unsigned char *__pskb_pull_tail(struct sk_buff *skb, int delta);
1128 static inline unsigned char *__pskb_pull(struct sk_buff *skb, unsigned int len)
1130 if (len > skb_headlen(skb) &&
1131 !__pskb_pull_tail(skb, len - skb_headlen(skb)))
1134 return skb->data += len;
1137 static inline unsigned char *pskb_pull(struct sk_buff *skb, unsigned int len)
1139 return unlikely(len > skb->len) ? NULL : __pskb_pull(skb, len);
1142 static inline int pskb_may_pull(struct sk_buff *skb, unsigned int len)
1144 if (likely(len <= skb_headlen(skb)))
1146 if (unlikely(len > skb->len))
1148 return __pskb_pull_tail(skb, len - skb_headlen(skb)) != NULL;
1152 * skb_headroom - bytes at buffer head
1153 * @skb: buffer to check
1155 * Return the number of bytes of free space at the head of an &sk_buff.
1157 static inline unsigned int skb_headroom(const struct sk_buff *skb)
1159 return skb->data - skb->head;
1163 * skb_tailroom - bytes at buffer end
1164 * @skb: buffer to check
1166 * Return the number of bytes of free space at the tail of an sk_buff
1168 static inline int skb_tailroom(const struct sk_buff *skb)
1170 return skb_is_nonlinear(skb) ? 0 : skb->end - skb->tail;
1174 * skb_reserve - adjust headroom
1175 * @skb: buffer to alter
1176 * @len: bytes to move
1178 * Increase the headroom of an empty &sk_buff by reducing the tail
1179 * room. This is only allowed for an empty buffer.
1181 static inline void skb_reserve(struct sk_buff *skb, int len)
1187 #ifdef NET_SKBUFF_DATA_USES_OFFSET
1188 static inline unsigned char *skb_transport_header(const struct sk_buff *skb)
1190 return skb->head + skb->transport_header;
1193 static inline void skb_reset_transport_header(struct sk_buff *skb)
1195 skb->transport_header = skb->data - skb->head;
1198 static inline void skb_set_transport_header(struct sk_buff *skb,
1201 skb_reset_transport_header(skb);
1202 skb->transport_header += offset;
1205 static inline unsigned char *skb_network_header(const struct sk_buff *skb)
1207 return skb->head + skb->network_header;
1210 static inline void skb_reset_network_header(struct sk_buff *skb)
1212 skb->network_header = skb->data - skb->head;
1215 static inline void skb_set_network_header(struct sk_buff *skb, const int offset)
1217 skb_reset_network_header(skb);
1218 skb->network_header += offset;
1221 static inline unsigned char *skb_mac_header(const struct sk_buff *skb)
1223 return skb->head + skb->mac_header;
1226 static inline int skb_mac_header_was_set(const struct sk_buff *skb)
1228 return skb->mac_header != ~0U;
1231 static inline void skb_reset_mac_header(struct sk_buff *skb)
1233 skb->mac_header = skb->data - skb->head;
1236 static inline void skb_set_mac_header(struct sk_buff *skb, const int offset)
1238 skb_reset_mac_header(skb);
1239 skb->mac_header += offset;
1242 #else /* NET_SKBUFF_DATA_USES_OFFSET */
1244 static inline unsigned char *skb_transport_header(const struct sk_buff *skb)
1246 return skb->transport_header;
1249 static inline void skb_reset_transport_header(struct sk_buff *skb)
1251 skb->transport_header = skb->data;
1254 static inline void skb_set_transport_header(struct sk_buff *skb,
1257 skb->transport_header = skb->data + offset;
1260 static inline unsigned char *skb_network_header(const struct sk_buff *skb)
1262 return skb->network_header;
1265 static inline void skb_reset_network_header(struct sk_buff *skb)
1267 skb->network_header = skb->data;
1270 static inline void skb_set_network_header(struct sk_buff *skb, const int offset)
1272 skb->network_header = skb->data + offset;
1275 static inline unsigned char *skb_mac_header(const struct sk_buff *skb)
1277 return skb->mac_header;
1280 static inline int skb_mac_header_was_set(const struct sk_buff *skb)
1282 return skb->mac_header != NULL;
1285 static inline void skb_reset_mac_header(struct sk_buff *skb)
1287 skb->mac_header = skb->data;
1290 static inline void skb_set_mac_header(struct sk_buff *skb, const int offset)
1292 skb->mac_header = skb->data + offset;
1294 #endif /* NET_SKBUFF_DATA_USES_OFFSET */
1296 static inline int skb_transport_offset(const struct sk_buff *skb)
1298 return skb_transport_header(skb) - skb->data;
1301 static inline u32 skb_network_header_len(const struct sk_buff *skb)
1303 return skb->transport_header - skb->network_header;
1306 static inline int skb_network_offset(const struct sk_buff *skb)
1308 return skb_network_header(skb) - skb->data;
1312 * CPUs often take a performance hit when accessing unaligned memory
1313 * locations. The actual performance hit varies, it can be small if the
1314 * hardware handles it or large if we have to take an exception and fix it
1317 * Since an ethernet header is 14 bytes network drivers often end up with
1318 * the IP header at an unaligned offset. The IP header can be aligned by
1319 * shifting the start of the packet by 2 bytes. Drivers should do this
1322 * skb_reserve(NET_IP_ALIGN);
1324 * The downside to this alignment of the IP header is that the DMA is now
1325 * unaligned. On some architectures the cost of an unaligned DMA is high
1326 * and this cost outweighs the gains made by aligning the IP header.
1328 * Since this trade off varies between architectures, we allow NET_IP_ALIGN
1331 #ifndef NET_IP_ALIGN
1332 #define NET_IP_ALIGN 2
1336 * The networking layer reserves some headroom in skb data (via
1337 * dev_alloc_skb). This is used to avoid having to reallocate skb data when
1338 * the header has to grow. In the default case, if the header has to grow
1339 * 32 bytes or less we avoid the reallocation.
1341 * Unfortunately this headroom changes the DMA alignment of the resulting
1342 * network packet. As for NET_IP_ALIGN, this unaligned DMA is expensive
1343 * on some architectures. An architecture can override this value,
1344 * perhaps setting it to a cacheline in size (since that will maintain
1345 * cacheline alignment of the DMA). It must be a power of 2.
1347 * Various parts of the networking layer expect at least 32 bytes of
1348 * headroom, you should not reduce this.
1351 #define NET_SKB_PAD 32
1354 extern int ___pskb_trim(struct sk_buff *skb, unsigned int len);
1356 static inline void __skb_trim(struct sk_buff *skb, unsigned int len)
1358 if (unlikely(skb->data_len)) {
1363 skb_set_tail_pointer(skb, len);
1366 extern void skb_trim(struct sk_buff *skb, unsigned int len);
1368 static inline int __pskb_trim(struct sk_buff *skb, unsigned int len)
1371 return ___pskb_trim(skb, len);
1372 __skb_trim(skb, len);
1376 static inline int pskb_trim(struct sk_buff *skb, unsigned int len)
1378 return (len < skb->len) ? __pskb_trim(skb, len) : 0;
1382 * pskb_trim_unique - remove end from a paged unique (not cloned) buffer
1383 * @skb: buffer to alter
1386 * This is identical to pskb_trim except that the caller knows that
1387 * the skb is not cloned so we should never get an error due to out-
1390 static inline void pskb_trim_unique(struct sk_buff *skb, unsigned int len)
1392 int err = pskb_trim(skb, len);
1397 * skb_orphan - orphan a buffer
1398 * @skb: buffer to orphan
1400 * If a buffer currently has an owner then we call the owner's
1401 * destructor function and make the @skb unowned. The buffer continues
1402 * to exist but is no longer charged to its former owner.
1404 static inline void skb_orphan(struct sk_buff *skb)
1406 if (skb->destructor)
1407 skb->destructor(skb);
1408 skb->destructor = NULL;
1413 * __skb_queue_purge - empty a list
1414 * @list: list to empty
1416 * Delete all buffers on an &sk_buff list. Each buffer is removed from
1417 * the list and one reference dropped. This function does not take the
1418 * list lock and the caller must hold the relevant locks to use it.
1420 extern void skb_queue_purge(struct sk_buff_head *list);
1421 static inline void __skb_queue_purge(struct sk_buff_head *list)
1423 struct sk_buff *skb;
1424 while ((skb = __skb_dequeue(list)) != NULL)
1429 * __dev_alloc_skb - allocate an skbuff for receiving
1430 * @length: length to allocate
1431 * @gfp_mask: get_free_pages mask, passed to alloc_skb
1433 * Allocate a new &sk_buff and assign it a usage count of one. The
1434 * buffer has unspecified headroom built in. Users should allocate
1435 * the headroom they think they need without accounting for the
1436 * built in space. The built in space is used for optimisations.
1438 * %NULL is returned if there is no free memory.
1440 static inline struct sk_buff *__dev_alloc_skb(unsigned int length,
1443 struct sk_buff *skb = alloc_skb(length + NET_SKB_PAD, gfp_mask);
1445 skb_reserve(skb, NET_SKB_PAD);
1449 extern struct sk_buff *dev_alloc_skb(unsigned int length);
1451 extern struct sk_buff *__netdev_alloc_skb(struct net_device *dev,
1452 unsigned int length, gfp_t gfp_mask);
1455 * netdev_alloc_skb - allocate an skbuff for rx on a specific device
1456 * @dev: network device to receive on
1457 * @length: length to allocate
1459 * Allocate a new &sk_buff and assign it a usage count of one. The
1460 * buffer has unspecified headroom built in. Users should allocate
1461 * the headroom they think they need without accounting for the
1462 * built in space. The built in space is used for optimisations.
1464 * %NULL is returned if there is no free memory. Although this function
1465 * allocates memory it can be called from an interrupt.
1467 static inline struct sk_buff *netdev_alloc_skb(struct net_device *dev,
1468 unsigned int length)
1470 return __netdev_alloc_skb(dev, length, GFP_ATOMIC);
1473 extern struct page *__netdev_alloc_page(struct net_device *dev, gfp_t gfp_mask);
1476 * netdev_alloc_page - allocate a page for ps-rx on a specific device
1477 * @dev: network device to receive on
1479 * Allocate a new page node local to the specified device.
1481 * %NULL is returned if there is no free memory.
1483 static inline struct page *netdev_alloc_page(struct net_device *dev)
1485 return __netdev_alloc_page(dev, GFP_ATOMIC);
1488 static inline void netdev_free_page(struct net_device *dev, struct page *page)
1494 * skb_clone_writable - is the header of a clone writable
1495 * @skb: buffer to check
1496 * @len: length up to which to write
1498 * Returns true if modifying the header part of the cloned buffer
1499 * does not requires the data to be copied.
1501 static inline int skb_clone_writable(struct sk_buff *skb, unsigned int len)
1503 return !skb_header_cloned(skb) &&
1504 skb_headroom(skb) + len <= skb->hdr_len;
1507 static inline int __skb_cow(struct sk_buff *skb, unsigned int headroom,
1512 if (headroom < NET_SKB_PAD)
1513 headroom = NET_SKB_PAD;
1514 if (headroom > skb_headroom(skb))
1515 delta = headroom - skb_headroom(skb);
1517 if (delta || cloned)
1518 return pskb_expand_head(skb, ALIGN(delta, NET_SKB_PAD), 0,
1524 * skb_cow - copy header of skb when it is required
1525 * @skb: buffer to cow
1526 * @headroom: needed headroom
1528 * If the skb passed lacks sufficient headroom or its data part
1529 * is shared, data is reallocated. If reallocation fails, an error
1530 * is returned and original skb is not changed.
1532 * The result is skb with writable area skb->head...skb->tail
1533 * and at least @headroom of space at head.
1535 static inline int skb_cow(struct sk_buff *skb, unsigned int headroom)
1537 return __skb_cow(skb, headroom, skb_cloned(skb));
1541 * skb_cow_head - skb_cow but only making the head writable
1542 * @skb: buffer to cow
1543 * @headroom: needed headroom
1545 * This function is identical to skb_cow except that we replace the
1546 * skb_cloned check by skb_header_cloned. It should be used when
1547 * you only need to push on some header and do not need to modify
1550 static inline int skb_cow_head(struct sk_buff *skb, unsigned int headroom)
1552 return __skb_cow(skb, headroom, skb_header_cloned(skb));
1556 * skb_padto - pad an skbuff up to a minimal size
1557 * @skb: buffer to pad
1558 * @len: minimal length
1560 * Pads up a buffer to ensure the trailing bytes exist and are
1561 * blanked. If the buffer already contains sufficient data it
1562 * is untouched. Otherwise it is extended. Returns zero on
1563 * success. The skb is freed on error.
1566 static inline int skb_padto(struct sk_buff *skb, unsigned int len)
1568 unsigned int size = skb->len;
1569 if (likely(size >= len))
1571 return skb_pad(skb, len - size);
1574 static inline int skb_add_data(struct sk_buff *skb,
1575 char __user *from, int copy)
1577 const int off = skb->len;
1579 if (skb->ip_summed == CHECKSUM_NONE) {
1581 __wsum csum = csum_and_copy_from_user(from, skb_put(skb, copy),
1584 skb->csum = csum_block_add(skb->csum, csum, off);
1587 } else if (!copy_from_user(skb_put(skb, copy), from, copy))
1590 __skb_trim(skb, off);
1594 static inline int skb_can_coalesce(struct sk_buff *skb, int i,
1595 struct page *page, int off)
1598 struct skb_frag_struct *frag = &skb_shinfo(skb)->frags[i - 1];
1600 return page == frag->page &&
1601 off == frag->page_offset + frag->size;
1606 static inline int __skb_linearize(struct sk_buff *skb)
1608 return __pskb_pull_tail(skb, skb->data_len) ? 0 : -ENOMEM;
1612 * skb_linearize - convert paged skb to linear one
1613 * @skb: buffer to linarize
1615 * If there is no free memory -ENOMEM is returned, otherwise zero
1616 * is returned and the old skb data released.
1618 static inline int skb_linearize(struct sk_buff *skb)
1620 return skb_is_nonlinear(skb) ? __skb_linearize(skb) : 0;
1624 * skb_linearize_cow - make sure skb is linear and writable
1625 * @skb: buffer to process
1627 * If there is no free memory -ENOMEM is returned, otherwise zero
1628 * is returned and the old skb data released.
1630 static inline int skb_linearize_cow(struct sk_buff *skb)
1632 return skb_is_nonlinear(skb) || skb_cloned(skb) ?
1633 __skb_linearize(skb) : 0;
1637 * skb_postpull_rcsum - update checksum for received skb after pull
1638 * @skb: buffer to update
1639 * @start: start of data before pull
1640 * @len: length of data pulled
1642 * After doing a pull on a received packet, you need to call this to
1643 * update the CHECKSUM_COMPLETE checksum, or set ip_summed to
1644 * CHECKSUM_NONE so that it can be recomputed from scratch.
1647 static inline void skb_postpull_rcsum(struct sk_buff *skb,
1648 const void *start, unsigned int len)
1650 if (skb->ip_summed == CHECKSUM_COMPLETE)
1651 skb->csum = csum_sub(skb->csum, csum_partial(start, len, 0));
1654 unsigned char *skb_pull_rcsum(struct sk_buff *skb, unsigned int len);
1657 * pskb_trim_rcsum - trim received skb and update checksum
1658 * @skb: buffer to trim
1661 * This is exactly the same as pskb_trim except that it ensures the
1662 * checksum of received packets are still valid after the operation.
1665 static inline int pskb_trim_rcsum(struct sk_buff *skb, unsigned int len)
1667 if (likely(len >= skb->len))
1669 if (skb->ip_summed == CHECKSUM_COMPLETE)
1670 skb->ip_summed = CHECKSUM_NONE;
1671 return __pskb_trim(skb, len);
1674 #define skb_queue_walk(queue, skb) \
1675 for (skb = (queue)->next; \
1676 prefetch(skb->next), (skb != (struct sk_buff *)(queue)); \
1679 #define skb_queue_walk_safe(queue, skb, tmp) \
1680 for (skb = (queue)->next, tmp = skb->next; \
1681 skb != (struct sk_buff *)(queue); \
1682 skb = tmp, tmp = skb->next)
1684 #define skb_queue_walk_from(queue, skb) \
1685 for (; prefetch(skb->next), (skb != (struct sk_buff *)(queue)); \
1688 #define skb_queue_walk_from_safe(queue, skb, tmp) \
1689 for (tmp = skb->next; \
1690 skb != (struct sk_buff *)(queue); \
1691 skb = tmp, tmp = skb->next)
1693 #define skb_queue_reverse_walk(queue, skb) \
1694 for (skb = (queue)->prev; \
1695 prefetch(skb->prev), (skb != (struct sk_buff *)(queue)); \
1699 extern struct sk_buff *__skb_recv_datagram(struct sock *sk, unsigned flags,
1700 int *peeked, int *err);
1701 extern struct sk_buff *skb_recv_datagram(struct sock *sk, unsigned flags,
1702 int noblock, int *err);
1703 extern unsigned int datagram_poll(struct file *file, struct socket *sock,
1704 struct poll_table_struct *wait);
1705 extern int skb_copy_datagram_iovec(const struct sk_buff *from,
1706 int offset, struct iovec *to,
1708 extern int skb_copy_and_csum_datagram_iovec(struct sk_buff *skb,
1711 extern int skb_copy_datagram_from_iovec(struct sk_buff *skb,
1715 extern void skb_free_datagram(struct sock *sk, struct sk_buff *skb);
1716 extern int skb_kill_datagram(struct sock *sk, struct sk_buff *skb,
1717 unsigned int flags);
1718 extern __wsum skb_checksum(const struct sk_buff *skb, int offset,
1719 int len, __wsum csum);
1720 extern int skb_copy_bits(const struct sk_buff *skb, int offset,
1722 extern int skb_store_bits(struct sk_buff *skb, int offset,
1723 const void *from, int len);
1724 extern __wsum skb_copy_and_csum_bits(const struct sk_buff *skb,
1725 int offset, u8 *to, int len,
1727 extern int skb_splice_bits(struct sk_buff *skb,
1728 unsigned int offset,
1729 struct pipe_inode_info *pipe,
1731 unsigned int flags);
1732 extern void skb_copy_and_csum_dev(const struct sk_buff *skb, u8 *to);
1733 extern void skb_split(struct sk_buff *skb,
1734 struct sk_buff *skb1, const u32 len);
1735 extern int skb_shift(struct sk_buff *tgt, struct sk_buff *skb,
1738 extern struct sk_buff *skb_segment(struct sk_buff *skb, int features);
1740 static inline void *skb_header_pointer(const struct sk_buff *skb, int offset,
1741 int len, void *buffer)
1743 int hlen = skb_headlen(skb);
1745 if (hlen - offset >= len)
1746 return skb->data + offset;
1748 if (skb_copy_bits(skb, offset, buffer, len) < 0)
1754 static inline void skb_copy_from_linear_data(const struct sk_buff *skb,
1756 const unsigned int len)
1758 memcpy(to, skb->data, len);
1761 static inline void skb_copy_from_linear_data_offset(const struct sk_buff *skb,
1762 const int offset, void *to,
1763 const unsigned int len)
1765 memcpy(to, skb->data + offset, len);
1768 static inline void skb_copy_to_linear_data(struct sk_buff *skb,
1770 const unsigned int len)
1772 memcpy(skb->data, from, len);
1775 static inline void skb_copy_to_linear_data_offset(struct sk_buff *skb,
1778 const unsigned int len)
1780 memcpy(skb->data + offset, from, len);
1783 extern void skb_init(void);
1785 static inline ktime_t skb_get_ktime(const struct sk_buff *skb)
1791 * skb_get_timestamp - get timestamp from a skb
1792 * @skb: skb to get stamp from
1793 * @stamp: pointer to struct timeval to store stamp in
1795 * Timestamps are stored in the skb as offsets to a base timestamp.
1796 * This function converts the offset back to a struct timeval and stores
1799 static inline void skb_get_timestamp(const struct sk_buff *skb,
1800 struct timeval *stamp)
1802 *stamp = ktime_to_timeval(skb->tstamp);
1805 static inline void skb_get_timestampns(const struct sk_buff *skb,
1806 struct timespec *stamp)
1808 *stamp = ktime_to_timespec(skb->tstamp);
1811 static inline void __net_timestamp(struct sk_buff *skb)
1813 skb->tstamp = ktime_get_real();
1816 static inline ktime_t net_timedelta(ktime_t t)
1818 return ktime_sub(ktime_get_real(), t);
1821 static inline ktime_t net_invalid_timestamp(void)
1823 return ktime_set(0, 0);
1827 * skb_tstamp_tx - queue clone of skb with send time stamps
1828 * @orig_skb: the original outgoing packet
1829 * @hwtstamps: hardware time stamps, may be NULL if not available
1831 * If the skb has a socket associated, then this function clones the
1832 * skb (thus sharing the actual data and optional structures), stores
1833 * the optional hardware time stamping information (if non NULL) or
1834 * generates a software time stamp (otherwise), then queues the clone
1835 * to the error queue of the socket. Errors are silently ignored.
1837 extern void skb_tstamp_tx(struct sk_buff *orig_skb,
1838 struct skb_shared_hwtstamps *hwtstamps);
1840 extern __sum16 __skb_checksum_complete_head(struct sk_buff *skb, int len);
1841 extern __sum16 __skb_checksum_complete(struct sk_buff *skb);
1843 static inline int skb_csum_unnecessary(const struct sk_buff *skb)
1845 return skb->ip_summed & CHECKSUM_UNNECESSARY;
1849 * skb_checksum_complete - Calculate checksum of an entire packet
1850 * @skb: packet to process
1852 * This function calculates the checksum over the entire packet plus
1853 * the value of skb->csum. The latter can be used to supply the
1854 * checksum of a pseudo header as used by TCP/UDP. It returns the
1857 * For protocols that contain complete checksums such as ICMP/TCP/UDP,
1858 * this function can be used to verify that checksum on received
1859 * packets. In that case the function should return zero if the
1860 * checksum is correct. In particular, this function will return zero
1861 * if skb->ip_summed is CHECKSUM_UNNECESSARY which indicates that the
1862 * hardware has already verified the correctness of the checksum.
1864 static inline __sum16 skb_checksum_complete(struct sk_buff *skb)
1866 return skb_csum_unnecessary(skb) ?
1867 0 : __skb_checksum_complete(skb);
1870 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
1871 extern void nf_conntrack_destroy(struct nf_conntrack *nfct);
1872 static inline void nf_conntrack_put(struct nf_conntrack *nfct)
1874 if (nfct && atomic_dec_and_test(&nfct->use))
1875 nf_conntrack_destroy(nfct);
1877 static inline void nf_conntrack_get(struct nf_conntrack *nfct)
1880 atomic_inc(&nfct->use);
1882 static inline void nf_conntrack_get_reasm(struct sk_buff *skb)
1885 atomic_inc(&skb->users);
1887 static inline void nf_conntrack_put_reasm(struct sk_buff *skb)
1893 #ifdef CONFIG_BRIDGE_NETFILTER
1894 static inline void nf_bridge_put(struct nf_bridge_info *nf_bridge)
1896 if (nf_bridge && atomic_dec_and_test(&nf_bridge->use))
1899 static inline void nf_bridge_get(struct nf_bridge_info *nf_bridge)
1902 atomic_inc(&nf_bridge->use);
1904 #endif /* CONFIG_BRIDGE_NETFILTER */
1905 static inline void nf_reset(struct sk_buff *skb)
1907 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
1908 nf_conntrack_put(skb->nfct);
1910 nf_conntrack_put_reasm(skb->nfct_reasm);
1911 skb->nfct_reasm = NULL;
1913 #ifdef CONFIG_BRIDGE_NETFILTER
1914 nf_bridge_put(skb->nf_bridge);
1915 skb->nf_bridge = NULL;
1919 /* Note: This doesn't put any conntrack and bridge info in dst. */
1920 static inline void __nf_copy(struct sk_buff *dst, const struct sk_buff *src)
1922 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
1923 dst->nfct = src->nfct;
1924 nf_conntrack_get(src->nfct);
1925 dst->nfctinfo = src->nfctinfo;
1926 dst->nfct_reasm = src->nfct_reasm;
1927 nf_conntrack_get_reasm(src->nfct_reasm);
1929 #ifdef CONFIG_BRIDGE_NETFILTER
1930 dst->nf_bridge = src->nf_bridge;
1931 nf_bridge_get(src->nf_bridge);
1935 static inline void nf_copy(struct sk_buff *dst, const struct sk_buff *src)
1937 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
1938 nf_conntrack_put(dst->nfct);
1939 nf_conntrack_put_reasm(dst->nfct_reasm);
1941 #ifdef CONFIG_BRIDGE_NETFILTER
1942 nf_bridge_put(dst->nf_bridge);
1944 __nf_copy(dst, src);
1947 #ifdef CONFIG_NETWORK_SECMARK
1948 static inline void skb_copy_secmark(struct sk_buff *to, const struct sk_buff *from)
1950 to->secmark = from->secmark;
1953 static inline void skb_init_secmark(struct sk_buff *skb)
1958 static inline void skb_copy_secmark(struct sk_buff *to, const struct sk_buff *from)
1961 static inline void skb_init_secmark(struct sk_buff *skb)
1965 static inline void skb_set_queue_mapping(struct sk_buff *skb, u16 queue_mapping)
1967 skb->queue_mapping = queue_mapping;
1970 static inline u16 skb_get_queue_mapping(struct sk_buff *skb)
1972 return skb->queue_mapping;
1975 static inline void skb_copy_queue_mapping(struct sk_buff *to, const struct sk_buff *from)
1977 to->queue_mapping = from->queue_mapping;
1980 static inline void skb_record_rx_queue(struct sk_buff *skb, u16 rx_queue)
1982 skb->queue_mapping = rx_queue + 1;
1985 static inline u16 skb_get_rx_queue(struct sk_buff *skb)
1987 return skb->queue_mapping - 1;
1990 static inline bool skb_rx_queue_recorded(struct sk_buff *skb)
1992 return (skb->queue_mapping != 0);
1996 static inline struct sec_path *skb_sec_path(struct sk_buff *skb)
2001 static inline struct sec_path *skb_sec_path(struct sk_buff *skb)
2007 static inline int skb_is_gso(const struct sk_buff *skb)
2009 return skb_shinfo(skb)->gso_size;
2012 static inline int skb_is_gso_v6(const struct sk_buff *skb)
2014 return skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6;
2017 extern void __skb_warn_lro_forwarding(const struct sk_buff *skb);
2019 static inline bool skb_warn_if_lro(const struct sk_buff *skb)
2021 /* LRO sets gso_size but not gso_type, whereas if GSO is really
2022 * wanted then gso_type will be set. */
2023 struct skb_shared_info *shinfo = skb_shinfo(skb);
2024 if (shinfo->gso_size != 0 && unlikely(shinfo->gso_type == 0)) {
2025 __skb_warn_lro_forwarding(skb);
2031 static inline void skb_forward_csum(struct sk_buff *skb)
2033 /* Unfortunately we don't support this one. Any brave souls? */
2034 if (skb->ip_summed == CHECKSUM_COMPLETE)
2035 skb->ip_summed = CHECKSUM_NONE;
2038 bool skb_partial_csum_set(struct sk_buff *skb, u16 start, u16 off);
2039 #endif /* __KERNEL__ */
2040 #endif /* _LINUX_SKBUFF_H */