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/kmemcheck.h>
19 #include <linux/compiler.h>
20 #include <linux/time.h>
21 #include <linux/cache.h>
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>
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
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))
48 /* A. Checksumming of received packets by device.
50 * NONE: device failed to checksum this packet.
51 * skb->csum is undefined.
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)
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,
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.
72 * B. Checksumming on output.
74 * NONE: skb is checksummed by protocol or csum is not required.
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.
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
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.
91 * Any questions? No questions, good. --ANK
96 struct pipe_inode_info;
98 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
104 #ifdef CONFIG_BRIDGE_NETFILTER
105 struct nf_bridge_info {
107 struct net_device *physindev;
108 struct net_device *physoutdev;
110 unsigned long data[32 / sizeof(unsigned long)];
114 struct sk_buff_head {
115 /* These two members must be first. */
116 struct sk_buff *next;
117 struct sk_buff *prev;
125 /* To allow 64K frame to be packed as single skb without frag_list */
126 #define MAX_SKB_FRAGS (65536/PAGE_SIZE + 2)
128 typedef struct skb_frag_struct skb_frag_t;
130 struct skb_frag_struct {
136 #define HAVE_HW_TIME_STAMP
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
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:
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
155 * hwtstamps can only be compared against other hwtstamps from
158 * This structure is attached to packets as part of the
159 * &skb_shared_info. Use skb_hwtstamps() to get a pointer.
161 struct skb_shared_hwtstamps {
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
174 * These flags are attached to packets as part of the
175 * &skb_shared_info. Use skb_tx() to get a pointer.
177 union skb_shared_tx {
186 /* This data is invariant across clones and lives at
187 * the end of the header data, ie. at skb->end.
189 struct skb_shared_info {
191 unsigned short nr_frags;
192 unsigned short gso_size;
193 /* Warning: this field is not always filled in (UFO)! */
194 unsigned short gso_segs;
195 unsigned short gso_type;
197 union skb_shared_tx tx_flags;
198 struct sk_buff *frag_list;
199 struct skb_shared_hwtstamps hwtstamps;
200 skb_frag_t frags[MAX_SKB_FRAGS];
201 /* Intermediate layers must ensure that destructor_arg
202 * remains valid until skb destructor */
203 void * destructor_arg;
206 /* We divide dataref into two halves. The higher 16 bits hold references
207 * to the payload part of skb->data. The lower 16 bits hold references to
208 * the entire skb->data. A clone of a headerless skb holds the length of
209 * the header in skb->hdr_len.
211 * All users must obey the rule that the skb->data reference count must be
212 * greater than or equal to the payload reference count.
214 * Holding a reference to the payload part means that the user does not
215 * care about modifications to the header part of skb->data.
217 #define SKB_DATAREF_SHIFT 16
218 #define SKB_DATAREF_MASK ((1 << SKB_DATAREF_SHIFT) - 1)
222 SKB_FCLONE_UNAVAILABLE,
228 SKB_GSO_TCPV4 = 1 << 0,
229 SKB_GSO_UDP = 1 << 1,
231 /* This indicates the skb is from an untrusted source. */
232 SKB_GSO_DODGY = 1 << 2,
234 /* This indicates the tcp segment has CWR set. */
235 SKB_GSO_TCP_ECN = 1 << 3,
237 SKB_GSO_TCPV6 = 1 << 4,
239 SKB_GSO_FCOE = 1 << 5,
242 #if BITS_PER_LONG > 32
243 #define NET_SKBUFF_DATA_USES_OFFSET 1
246 #ifdef NET_SKBUFF_DATA_USES_OFFSET
247 typedef unsigned int sk_buff_data_t;
249 typedef unsigned char *sk_buff_data_t;
253 * struct sk_buff - socket buffer
254 * @next: Next buffer in list
255 * @prev: Previous buffer in list
256 * @sk: Socket we are owned by
257 * @tstamp: Time we arrived
258 * @dev: Device we arrived on/are leaving by
259 * @transport_header: Transport layer header
260 * @network_header: Network layer header
261 * @mac_header: Link layer header
262 * @_skb_dst: destination entry
263 * @sp: the security path, used for xfrm
264 * @cb: Control buffer. Free for use by every layer. Put private vars here
265 * @len: Length of actual data
266 * @data_len: Data length
267 * @mac_len: Length of link layer header
268 * @hdr_len: writable header length of cloned skb
269 * @csum: Checksum (must include start/offset pair)
270 * @csum_start: Offset from skb->head where checksumming should start
271 * @csum_offset: Offset from csum_start where checksum should be stored
272 * @local_df: allow local fragmentation
273 * @cloned: Head may be cloned (check refcnt to be sure)
274 * @nohdr: Payload reference only, must not modify header
275 * @pkt_type: Packet class
276 * @fclone: skbuff clone status
277 * @ip_summed: Driver fed us an IP checksum
278 * @priority: Packet queueing priority
279 * @users: User count - see {datagram,tcp}.c
280 * @protocol: Packet protocol from driver
281 * @truesize: Buffer size
282 * @head: Head of buffer
283 * @data: Data head pointer
284 * @tail: Tail pointer
286 * @destructor: Destruct function
287 * @mark: Generic packet mark
288 * @nfct: Associated connection, if any
289 * @ipvs_property: skbuff is owned by ipvs
290 * @peeked: this packet has been seen already, so stats have been
291 * done for it, don't do them again
292 * @nf_trace: netfilter packet trace flag
293 * @nfctinfo: Relationship of this skb to the connection
294 * @nfct_reasm: netfilter conntrack re-assembly pointer
295 * @nf_bridge: Saved data about a bridged frame - see br_netfilter.c
296 * @skb_iif: ifindex of device we arrived on
297 * @rxhash: the packet hash computed on receive
298 * @queue_mapping: Queue mapping for multiqueue devices
299 * @tc_index: Traffic control index
300 * @tc_verd: traffic control verdict
301 * @ndisc_nodetype: router type (from link layer)
302 * @dma_cookie: a cookie to one of several possible DMA operations
303 * done by skb DMA functions
304 * @secmark: security marking
305 * @vlan_tci: vlan tag control information
309 /* These two members must be first. */
310 struct sk_buff *next;
311 struct sk_buff *prev;
316 struct net_device *dev;
319 * This is the control buffer. It is free to use for every
320 * layer. Please put your private variables there. If you
321 * want to keep them across layers you have to do a skb_clone()
322 * first. This is owned by whoever has the skb queued ATM.
324 char cb[48] __aligned(8);
326 unsigned long _skb_dst;
342 kmemcheck_bitfield_begin(flags1);
353 kmemcheck_bitfield_end(flags1);
356 void (*destructor)(struct sk_buff *skb);
357 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
358 struct nf_conntrack *nfct;
359 struct sk_buff *nfct_reasm;
361 #ifdef CONFIG_BRIDGE_NETFILTER
362 struct nf_bridge_info *nf_bridge;
366 #ifdef CONFIG_NET_SCHED
367 __u16 tc_index; /* traffic control index */
368 #ifdef CONFIG_NET_CLS_ACT
369 __u16 tc_verd; /* traffic control verdict */
375 kmemcheck_bitfield_begin(flags2);
376 __u16 queue_mapping:16;
377 #ifdef CONFIG_IPV6_NDISC_NODETYPE
378 __u8 ndisc_nodetype:2;
380 kmemcheck_bitfield_end(flags2);
384 #ifdef CONFIG_NET_DMA
385 dma_cookie_t dma_cookie;
387 #ifdef CONFIG_NETWORK_SECMARK
397 sk_buff_data_t transport_header;
398 sk_buff_data_t network_header;
399 sk_buff_data_t mac_header;
400 /* These elements must be at the end, see alloc_skb() for details. */
405 unsigned int truesize;
411 * Handling routines are only of interest to the kernel
413 #include <linux/slab.h>
415 #include <asm/system.h>
417 static inline struct dst_entry *skb_dst(const struct sk_buff *skb)
419 return (struct dst_entry *)skb->_skb_dst;
422 static inline void skb_dst_set(struct sk_buff *skb, struct dst_entry *dst)
424 skb->_skb_dst = (unsigned long)dst;
427 static inline struct rtable *skb_rtable(const struct sk_buff *skb)
429 return (struct rtable *)skb_dst(skb);
432 extern void kfree_skb(struct sk_buff *skb);
433 extern void consume_skb(struct sk_buff *skb);
434 extern void __kfree_skb(struct sk_buff *skb);
435 extern struct sk_buff *__alloc_skb(unsigned int size,
436 gfp_t priority, int fclone, int node);
437 static inline struct sk_buff *alloc_skb(unsigned int size,
440 return __alloc_skb(size, priority, 0, -1);
443 static inline struct sk_buff *alloc_skb_fclone(unsigned int size,
446 return __alloc_skb(size, priority, 1, -1);
449 extern int skb_recycle_check(struct sk_buff *skb, int skb_size);
451 extern struct sk_buff *skb_morph(struct sk_buff *dst, struct sk_buff *src);
452 extern struct sk_buff *skb_clone(struct sk_buff *skb,
454 extern struct sk_buff *skb_copy(const struct sk_buff *skb,
456 extern struct sk_buff *pskb_copy(struct sk_buff *skb,
458 extern int pskb_expand_head(struct sk_buff *skb,
459 int nhead, int ntail,
461 extern struct sk_buff *skb_realloc_headroom(struct sk_buff *skb,
462 unsigned int headroom);
463 extern struct sk_buff *skb_copy_expand(const struct sk_buff *skb,
464 int newheadroom, int newtailroom,
466 extern int skb_to_sgvec(struct sk_buff *skb,
467 struct scatterlist *sg, int offset,
469 extern int skb_cow_data(struct sk_buff *skb, int tailbits,
470 struct sk_buff **trailer);
471 extern int skb_pad(struct sk_buff *skb, int pad);
472 #define dev_kfree_skb(a) consume_skb(a)
474 extern int skb_append_datato_frags(struct sock *sk, struct sk_buff *skb,
475 int getfrag(void *from, char *to, int offset,
476 int len,int odd, struct sk_buff *skb),
477 void *from, int length);
479 struct skb_seq_state {
483 __u32 stepped_offset;
484 struct sk_buff *root_skb;
485 struct sk_buff *cur_skb;
489 extern void skb_prepare_seq_read(struct sk_buff *skb,
490 unsigned int from, unsigned int to,
491 struct skb_seq_state *st);
492 extern unsigned int skb_seq_read(unsigned int consumed, const u8 **data,
493 struct skb_seq_state *st);
494 extern void skb_abort_seq_read(struct skb_seq_state *st);
496 extern unsigned int skb_find_text(struct sk_buff *skb, unsigned int from,
497 unsigned int to, struct ts_config *config,
498 struct ts_state *state);
500 #ifdef NET_SKBUFF_DATA_USES_OFFSET
501 static inline unsigned char *skb_end_pointer(const struct sk_buff *skb)
503 return skb->head + skb->end;
506 static inline unsigned char *skb_end_pointer(const struct sk_buff *skb)
513 #define skb_shinfo(SKB) ((struct skb_shared_info *)(skb_end_pointer(SKB)))
515 static inline struct skb_shared_hwtstamps *skb_hwtstamps(struct sk_buff *skb)
517 return &skb_shinfo(skb)->hwtstamps;
520 static inline union skb_shared_tx *skb_tx(struct sk_buff *skb)
522 return &skb_shinfo(skb)->tx_flags;
526 * skb_queue_empty - check if a queue is empty
529 * Returns true if the queue is empty, false otherwise.
531 static inline int skb_queue_empty(const struct sk_buff_head *list)
533 return list->next == (struct sk_buff *)list;
537 * skb_queue_is_last - check if skb is the last entry in the queue
541 * Returns true if @skb is the last buffer on the list.
543 static inline bool skb_queue_is_last(const struct sk_buff_head *list,
544 const struct sk_buff *skb)
546 return (skb->next == (struct sk_buff *) list);
550 * skb_queue_is_first - check if skb is the first entry in the queue
554 * Returns true if @skb is the first buffer on the list.
556 static inline bool skb_queue_is_first(const struct sk_buff_head *list,
557 const struct sk_buff *skb)
559 return (skb->prev == (struct sk_buff *) list);
563 * skb_queue_next - return the next packet in the queue
565 * @skb: current buffer
567 * Return the next packet in @list after @skb. It is only valid to
568 * call this if skb_queue_is_last() evaluates to false.
570 static inline struct sk_buff *skb_queue_next(const struct sk_buff_head *list,
571 const struct sk_buff *skb)
573 /* This BUG_ON may seem severe, but if we just return then we
574 * are going to dereference garbage.
576 BUG_ON(skb_queue_is_last(list, skb));
581 * skb_queue_prev - return the prev packet in the queue
583 * @skb: current buffer
585 * Return the prev packet in @list before @skb. It is only valid to
586 * call this if skb_queue_is_first() evaluates to false.
588 static inline struct sk_buff *skb_queue_prev(const struct sk_buff_head *list,
589 const struct sk_buff *skb)
591 /* This BUG_ON may seem severe, but if we just return then we
592 * are going to dereference garbage.
594 BUG_ON(skb_queue_is_first(list, skb));
599 * skb_get - reference buffer
600 * @skb: buffer to reference
602 * Makes another reference to a socket buffer and returns a pointer
605 static inline struct sk_buff *skb_get(struct sk_buff *skb)
607 atomic_inc(&skb->users);
612 * If users == 1, we are the only owner and are can avoid redundant
617 * skb_cloned - is the buffer a clone
618 * @skb: buffer to check
620 * Returns true if the buffer was generated with skb_clone() and is
621 * one of multiple shared copies of the buffer. Cloned buffers are
622 * shared data so must not be written to under normal circumstances.
624 static inline int skb_cloned(const struct sk_buff *skb)
626 return skb->cloned &&
627 (atomic_read(&skb_shinfo(skb)->dataref) & SKB_DATAREF_MASK) != 1;
631 * skb_header_cloned - is the header a clone
632 * @skb: buffer to check
634 * Returns true if modifying the header part of the buffer requires
635 * the data to be copied.
637 static inline int skb_header_cloned(const struct sk_buff *skb)
644 dataref = atomic_read(&skb_shinfo(skb)->dataref);
645 dataref = (dataref & SKB_DATAREF_MASK) - (dataref >> SKB_DATAREF_SHIFT);
650 * skb_header_release - release reference to header
651 * @skb: buffer to operate on
653 * Drop a reference to the header part of the buffer. This is done
654 * by acquiring a payload reference. You must not read from the header
655 * part of skb->data after this.
657 static inline void skb_header_release(struct sk_buff *skb)
661 atomic_add(1 << SKB_DATAREF_SHIFT, &skb_shinfo(skb)->dataref);
665 * skb_shared - is the buffer shared
666 * @skb: buffer to check
668 * Returns true if more than one person has a reference to this
671 static inline int skb_shared(const struct sk_buff *skb)
673 return atomic_read(&skb->users) != 1;
677 * skb_share_check - check if buffer is shared and if so clone it
678 * @skb: buffer to check
679 * @pri: priority for memory allocation
681 * If the buffer is shared the buffer is cloned and the old copy
682 * drops a reference. A new clone with a single reference is returned.
683 * If the buffer is not shared the original buffer is returned. When
684 * being called from interrupt status or with spinlocks held pri must
687 * NULL is returned on a memory allocation failure.
689 static inline struct sk_buff *skb_share_check(struct sk_buff *skb,
692 might_sleep_if(pri & __GFP_WAIT);
693 if (skb_shared(skb)) {
694 struct sk_buff *nskb = skb_clone(skb, pri);
702 * Copy shared buffers into a new sk_buff. We effectively do COW on
703 * packets to handle cases where we have a local reader and forward
704 * and a couple of other messy ones. The normal one is tcpdumping
705 * a packet thats being forwarded.
709 * skb_unshare - make a copy of a shared buffer
710 * @skb: buffer to check
711 * @pri: priority for memory allocation
713 * If the socket buffer is a clone then this function creates a new
714 * copy of the data, drops a reference count on the old copy and returns
715 * the new copy with the reference count at 1. If the buffer is not a clone
716 * the original buffer is returned. When called with a spinlock held or
717 * from interrupt state @pri must be %GFP_ATOMIC
719 * %NULL is returned on a memory allocation failure.
721 static inline struct sk_buff *skb_unshare(struct sk_buff *skb,
724 might_sleep_if(pri & __GFP_WAIT);
725 if (skb_cloned(skb)) {
726 struct sk_buff *nskb = skb_copy(skb, pri);
727 kfree_skb(skb); /* Free our shared copy */
734 * skb_peek - peek at the head of an &sk_buff_head
735 * @list_: list to peek at
737 * Peek an &sk_buff. Unlike most other operations you _MUST_
738 * be careful with this one. A peek leaves the buffer on the
739 * list and someone else may run off with it. You must hold
740 * the appropriate locks or have a private queue to do this.
742 * Returns %NULL for an empty list or a pointer to the head element.
743 * The reference count is not incremented and the reference is therefore
744 * volatile. Use with caution.
746 static inline struct sk_buff *skb_peek(struct sk_buff_head *list_)
748 struct sk_buff *list = ((struct sk_buff *)list_)->next;
749 if (list == (struct sk_buff *)list_)
755 * skb_peek_tail - peek at the tail of an &sk_buff_head
756 * @list_: list to peek at
758 * Peek an &sk_buff. Unlike most other operations you _MUST_
759 * be careful with this one. A peek leaves the buffer on the
760 * list and someone else may run off with it. You must hold
761 * the appropriate locks or have a private queue to do this.
763 * Returns %NULL for an empty list or a pointer to the tail element.
764 * The reference count is not incremented and the reference is therefore
765 * volatile. Use with caution.
767 static inline struct sk_buff *skb_peek_tail(struct sk_buff_head *list_)
769 struct sk_buff *list = ((struct sk_buff *)list_)->prev;
770 if (list == (struct sk_buff *)list_)
776 * skb_queue_len - get queue length
777 * @list_: list to measure
779 * Return the length of an &sk_buff queue.
781 static inline __u32 skb_queue_len(const struct sk_buff_head *list_)
787 * __skb_queue_head_init - initialize non-spinlock portions of sk_buff_head
788 * @list: queue to initialize
790 * This initializes only the list and queue length aspects of
791 * an sk_buff_head object. This allows to initialize the list
792 * aspects of an sk_buff_head without reinitializing things like
793 * the spinlock. It can also be used for on-stack sk_buff_head
794 * objects where the spinlock is known to not be used.
796 static inline void __skb_queue_head_init(struct sk_buff_head *list)
798 list->prev = list->next = (struct sk_buff *)list;
803 * This function creates a split out lock class for each invocation;
804 * this is needed for now since a whole lot of users of the skb-queue
805 * infrastructure in drivers have different locking usage (in hardirq)
806 * than the networking core (in softirq only). In the long run either the
807 * network layer or drivers should need annotation to consolidate the
808 * main types of usage into 3 classes.
810 static inline void skb_queue_head_init(struct sk_buff_head *list)
812 spin_lock_init(&list->lock);
813 __skb_queue_head_init(list);
816 static inline void skb_queue_head_init_class(struct sk_buff_head *list,
817 struct lock_class_key *class)
819 skb_queue_head_init(list);
820 lockdep_set_class(&list->lock, class);
824 * Insert an sk_buff on a list.
826 * The "__skb_xxxx()" functions are the non-atomic ones that
827 * can only be called with interrupts disabled.
829 extern void skb_insert(struct sk_buff *old, struct sk_buff *newsk, struct sk_buff_head *list);
830 static inline void __skb_insert(struct sk_buff *newsk,
831 struct sk_buff *prev, struct sk_buff *next,
832 struct sk_buff_head *list)
836 next->prev = prev->next = newsk;
840 static inline void __skb_queue_splice(const struct sk_buff_head *list,
841 struct sk_buff *prev,
842 struct sk_buff *next)
844 struct sk_buff *first = list->next;
845 struct sk_buff *last = list->prev;
855 * skb_queue_splice - join two skb lists, this is designed for stacks
856 * @list: the new list to add
857 * @head: the place to add it in the first list
859 static inline void skb_queue_splice(const struct sk_buff_head *list,
860 struct sk_buff_head *head)
862 if (!skb_queue_empty(list)) {
863 __skb_queue_splice(list, (struct sk_buff *) head, head->next);
864 head->qlen += list->qlen;
869 * skb_queue_splice - join two skb lists and reinitialise the emptied list
870 * @list: the new list to add
871 * @head: the place to add it in the first list
873 * The list at @list is reinitialised
875 static inline void skb_queue_splice_init(struct sk_buff_head *list,
876 struct sk_buff_head *head)
878 if (!skb_queue_empty(list)) {
879 __skb_queue_splice(list, (struct sk_buff *) head, head->next);
880 head->qlen += list->qlen;
881 __skb_queue_head_init(list);
886 * skb_queue_splice_tail - join two skb lists, each list being a queue
887 * @list: the new list to add
888 * @head: the place to add it in the first list
890 static inline void skb_queue_splice_tail(const struct sk_buff_head *list,
891 struct sk_buff_head *head)
893 if (!skb_queue_empty(list)) {
894 __skb_queue_splice(list, head->prev, (struct sk_buff *) head);
895 head->qlen += list->qlen;
900 * skb_queue_splice_tail - join two skb lists and reinitialise the emptied list
901 * @list: the new list to add
902 * @head: the place to add it in the first list
904 * Each of the lists is a queue.
905 * The list at @list is reinitialised
907 static inline void skb_queue_splice_tail_init(struct sk_buff_head *list,
908 struct sk_buff_head *head)
910 if (!skb_queue_empty(list)) {
911 __skb_queue_splice(list, head->prev, (struct sk_buff *) head);
912 head->qlen += list->qlen;
913 __skb_queue_head_init(list);
918 * __skb_queue_after - queue a buffer at the list head
920 * @prev: place after this buffer
921 * @newsk: buffer to queue
923 * Queue a buffer int the middle of a list. This function takes no locks
924 * and you must therefore hold required locks before calling it.
926 * A buffer cannot be placed on two lists at the same time.
928 static inline void __skb_queue_after(struct sk_buff_head *list,
929 struct sk_buff *prev,
930 struct sk_buff *newsk)
932 __skb_insert(newsk, prev, prev->next, list);
935 extern void skb_append(struct sk_buff *old, struct sk_buff *newsk,
936 struct sk_buff_head *list);
938 static inline void __skb_queue_before(struct sk_buff_head *list,
939 struct sk_buff *next,
940 struct sk_buff *newsk)
942 __skb_insert(newsk, next->prev, next, list);
946 * __skb_queue_head - queue a buffer at the list head
948 * @newsk: buffer to queue
950 * Queue a buffer at the start of a list. This function takes no locks
951 * and you must therefore hold required locks before calling it.
953 * A buffer cannot be placed on two lists at the same time.
955 extern void skb_queue_head(struct sk_buff_head *list, struct sk_buff *newsk);
956 static inline void __skb_queue_head(struct sk_buff_head *list,
957 struct sk_buff *newsk)
959 __skb_queue_after(list, (struct sk_buff *)list, newsk);
963 * __skb_queue_tail - queue a buffer at the list tail
965 * @newsk: buffer to queue
967 * Queue a buffer at the end of a list. This function takes no locks
968 * and you must therefore hold required locks before calling it.
970 * A buffer cannot be placed on two lists at the same time.
972 extern void skb_queue_tail(struct sk_buff_head *list, struct sk_buff *newsk);
973 static inline void __skb_queue_tail(struct sk_buff_head *list,
974 struct sk_buff *newsk)
976 __skb_queue_before(list, (struct sk_buff *)list, newsk);
980 * remove sk_buff from list. _Must_ be called atomically, and with
983 extern void skb_unlink(struct sk_buff *skb, struct sk_buff_head *list);
984 static inline void __skb_unlink(struct sk_buff *skb, struct sk_buff_head *list)
986 struct sk_buff *next, *prev;
991 skb->next = skb->prev = NULL;
997 * __skb_dequeue - remove from the head of the queue
998 * @list: list to dequeue from
1000 * Remove the head of the list. This function does not take any locks
1001 * so must be used with appropriate locks held only. The head item is
1002 * returned or %NULL if the list is empty.
1004 extern struct sk_buff *skb_dequeue(struct sk_buff_head *list);
1005 static inline struct sk_buff *__skb_dequeue(struct sk_buff_head *list)
1007 struct sk_buff *skb = skb_peek(list);
1009 __skb_unlink(skb, list);
1014 * __skb_dequeue_tail - remove from the tail of the queue
1015 * @list: list to dequeue from
1017 * Remove the tail of the list. This function does not take any locks
1018 * so must be used with appropriate locks held only. The tail item is
1019 * returned or %NULL if the list is empty.
1021 extern struct sk_buff *skb_dequeue_tail(struct sk_buff_head *list);
1022 static inline struct sk_buff *__skb_dequeue_tail(struct sk_buff_head *list)
1024 struct sk_buff *skb = skb_peek_tail(list);
1026 __skb_unlink(skb, list);
1031 static inline int skb_is_nonlinear(const struct sk_buff *skb)
1033 return skb->data_len;
1036 static inline unsigned int skb_headlen(const struct sk_buff *skb)
1038 return skb->len - skb->data_len;
1041 static inline int skb_pagelen(const struct sk_buff *skb)
1045 for (i = (int)skb_shinfo(skb)->nr_frags - 1; i >= 0; i--)
1046 len += skb_shinfo(skb)->frags[i].size;
1047 return len + skb_headlen(skb);
1050 static inline void skb_fill_page_desc(struct sk_buff *skb, int i,
1051 struct page *page, int off, int size)
1053 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
1056 frag->page_offset = off;
1058 skb_shinfo(skb)->nr_frags = i + 1;
1061 extern void skb_add_rx_frag(struct sk_buff *skb, int i, struct page *page,
1064 #define SKB_PAGE_ASSERT(skb) BUG_ON(skb_shinfo(skb)->nr_frags)
1065 #define SKB_FRAG_ASSERT(skb) BUG_ON(skb_has_frags(skb))
1066 #define SKB_LINEAR_ASSERT(skb) BUG_ON(skb_is_nonlinear(skb))
1068 #ifdef NET_SKBUFF_DATA_USES_OFFSET
1069 static inline unsigned char *skb_tail_pointer(const struct sk_buff *skb)
1071 return skb->head + skb->tail;
1074 static inline void skb_reset_tail_pointer(struct sk_buff *skb)
1076 skb->tail = skb->data - skb->head;
1079 static inline void skb_set_tail_pointer(struct sk_buff *skb, const int offset)
1081 skb_reset_tail_pointer(skb);
1082 skb->tail += offset;
1084 #else /* NET_SKBUFF_DATA_USES_OFFSET */
1085 static inline unsigned char *skb_tail_pointer(const struct sk_buff *skb)
1090 static inline void skb_reset_tail_pointer(struct sk_buff *skb)
1092 skb->tail = skb->data;
1095 static inline void skb_set_tail_pointer(struct sk_buff *skb, const int offset)
1097 skb->tail = skb->data + offset;
1100 #endif /* NET_SKBUFF_DATA_USES_OFFSET */
1103 * Add data to an sk_buff
1105 extern unsigned char *skb_put(struct sk_buff *skb, unsigned int len);
1106 static inline unsigned char *__skb_put(struct sk_buff *skb, unsigned int len)
1108 unsigned char *tmp = skb_tail_pointer(skb);
1109 SKB_LINEAR_ASSERT(skb);
1115 extern unsigned char *skb_push(struct sk_buff *skb, unsigned int len);
1116 static inline unsigned char *__skb_push(struct sk_buff *skb, unsigned int len)
1123 extern unsigned char *skb_pull(struct sk_buff *skb, unsigned int len);
1124 static inline unsigned char *__skb_pull(struct sk_buff *skb, unsigned int len)
1127 BUG_ON(skb->len < skb->data_len);
1128 return skb->data += len;
1131 extern unsigned char *__pskb_pull_tail(struct sk_buff *skb, int delta);
1133 static inline unsigned char *__pskb_pull(struct sk_buff *skb, unsigned int len)
1135 if (len > skb_headlen(skb) &&
1136 !__pskb_pull_tail(skb, len - skb_headlen(skb)))
1139 return skb->data += len;
1142 static inline unsigned char *pskb_pull(struct sk_buff *skb, unsigned int len)
1144 return unlikely(len > skb->len) ? NULL : __pskb_pull(skb, len);
1147 static inline int pskb_may_pull(struct sk_buff *skb, unsigned int len)
1149 if (likely(len <= skb_headlen(skb)))
1151 if (unlikely(len > skb->len))
1153 return __pskb_pull_tail(skb, len - skb_headlen(skb)) != NULL;
1157 * skb_headroom - bytes at buffer head
1158 * @skb: buffer to check
1160 * Return the number of bytes of free space at the head of an &sk_buff.
1162 static inline unsigned int skb_headroom(const struct sk_buff *skb)
1164 return skb->data - skb->head;
1168 * skb_tailroom - bytes at buffer end
1169 * @skb: buffer to check
1171 * Return the number of bytes of free space at the tail of an sk_buff
1173 static inline int skb_tailroom(const struct sk_buff *skb)
1175 return skb_is_nonlinear(skb) ? 0 : skb->end - skb->tail;
1179 * skb_reserve - adjust headroom
1180 * @skb: buffer to alter
1181 * @len: bytes to move
1183 * Increase the headroom of an empty &sk_buff by reducing the tail
1184 * room. This is only allowed for an empty buffer.
1186 static inline void skb_reserve(struct sk_buff *skb, int len)
1192 #ifdef NET_SKBUFF_DATA_USES_OFFSET
1193 static inline unsigned char *skb_transport_header(const struct sk_buff *skb)
1195 return skb->head + skb->transport_header;
1198 static inline void skb_reset_transport_header(struct sk_buff *skb)
1200 skb->transport_header = skb->data - skb->head;
1203 static inline void skb_set_transport_header(struct sk_buff *skb,
1206 skb_reset_transport_header(skb);
1207 skb->transport_header += offset;
1210 static inline unsigned char *skb_network_header(const struct sk_buff *skb)
1212 return skb->head + skb->network_header;
1215 static inline void skb_reset_network_header(struct sk_buff *skb)
1217 skb->network_header = skb->data - skb->head;
1220 static inline void skb_set_network_header(struct sk_buff *skb, const int offset)
1222 skb_reset_network_header(skb);
1223 skb->network_header += offset;
1226 static inline unsigned char *skb_mac_header(const struct sk_buff *skb)
1228 return skb->head + skb->mac_header;
1231 static inline int skb_mac_header_was_set(const struct sk_buff *skb)
1233 return skb->mac_header != ~0U;
1236 static inline void skb_reset_mac_header(struct sk_buff *skb)
1238 skb->mac_header = skb->data - skb->head;
1241 static inline void skb_set_mac_header(struct sk_buff *skb, const int offset)
1243 skb_reset_mac_header(skb);
1244 skb->mac_header += offset;
1247 #else /* NET_SKBUFF_DATA_USES_OFFSET */
1249 static inline unsigned char *skb_transport_header(const struct sk_buff *skb)
1251 return skb->transport_header;
1254 static inline void skb_reset_transport_header(struct sk_buff *skb)
1256 skb->transport_header = skb->data;
1259 static inline void skb_set_transport_header(struct sk_buff *skb,
1262 skb->transport_header = skb->data + offset;
1265 static inline unsigned char *skb_network_header(const struct sk_buff *skb)
1267 return skb->network_header;
1270 static inline void skb_reset_network_header(struct sk_buff *skb)
1272 skb->network_header = skb->data;
1275 static inline void skb_set_network_header(struct sk_buff *skb, const int offset)
1277 skb->network_header = skb->data + offset;
1280 static inline unsigned char *skb_mac_header(const struct sk_buff *skb)
1282 return skb->mac_header;
1285 static inline int skb_mac_header_was_set(const struct sk_buff *skb)
1287 return skb->mac_header != NULL;
1290 static inline void skb_reset_mac_header(struct sk_buff *skb)
1292 skb->mac_header = skb->data;
1295 static inline void skb_set_mac_header(struct sk_buff *skb, const int offset)
1297 skb->mac_header = skb->data + offset;
1299 #endif /* NET_SKBUFF_DATA_USES_OFFSET */
1301 static inline int skb_transport_offset(const struct sk_buff *skb)
1303 return skb_transport_header(skb) - skb->data;
1306 static inline u32 skb_network_header_len(const struct sk_buff *skb)
1308 return skb->transport_header - skb->network_header;
1311 static inline int skb_network_offset(const struct sk_buff *skb)
1313 return skb_network_header(skb) - skb->data;
1317 * CPUs often take a performance hit when accessing unaligned memory
1318 * locations. The actual performance hit varies, it can be small if the
1319 * hardware handles it or large if we have to take an exception and fix it
1322 * Since an ethernet header is 14 bytes network drivers often end up with
1323 * the IP header at an unaligned offset. The IP header can be aligned by
1324 * shifting the start of the packet by 2 bytes. Drivers should do this
1327 * skb_reserve(skb, NET_IP_ALIGN);
1329 * The downside to this alignment of the IP header is that the DMA is now
1330 * unaligned. On some architectures the cost of an unaligned DMA is high
1331 * and this cost outweighs the gains made by aligning the IP header.
1333 * Since this trade off varies between architectures, we allow NET_IP_ALIGN
1336 #ifndef NET_IP_ALIGN
1337 #define NET_IP_ALIGN 2
1341 * The networking layer reserves some headroom in skb data (via
1342 * dev_alloc_skb). This is used to avoid having to reallocate skb data when
1343 * the header has to grow. In the default case, if the header has to grow
1344 * 32 bytes or less we avoid the reallocation.
1346 * Unfortunately this headroom changes the DMA alignment of the resulting
1347 * network packet. As for NET_IP_ALIGN, this unaligned DMA is expensive
1348 * on some architectures. An architecture can override this value,
1349 * perhaps setting it to a cacheline in size (since that will maintain
1350 * cacheline alignment of the DMA). It must be a power of 2.
1352 * Various parts of the networking layer expect at least 32 bytes of
1353 * headroom, you should not reduce this.
1356 #define NET_SKB_PAD 32
1359 extern int ___pskb_trim(struct sk_buff *skb, unsigned int len);
1361 static inline void __skb_trim(struct sk_buff *skb, unsigned int len)
1363 if (unlikely(skb->data_len)) {
1368 skb_set_tail_pointer(skb, len);
1371 extern void skb_trim(struct sk_buff *skb, unsigned int len);
1373 static inline int __pskb_trim(struct sk_buff *skb, unsigned int len)
1376 return ___pskb_trim(skb, len);
1377 __skb_trim(skb, len);
1381 static inline int pskb_trim(struct sk_buff *skb, unsigned int len)
1383 return (len < skb->len) ? __pskb_trim(skb, len) : 0;
1387 * pskb_trim_unique - remove end from a paged unique (not cloned) buffer
1388 * @skb: buffer to alter
1391 * This is identical to pskb_trim except that the caller knows that
1392 * the skb is not cloned so we should never get an error due to out-
1395 static inline void pskb_trim_unique(struct sk_buff *skb, unsigned int len)
1397 int err = pskb_trim(skb, len);
1402 * skb_orphan - orphan a buffer
1403 * @skb: buffer to orphan
1405 * If a buffer currently has an owner then we call the owner's
1406 * destructor function and make the @skb unowned. The buffer continues
1407 * to exist but is no longer charged to its former owner.
1409 static inline void skb_orphan(struct sk_buff *skb)
1411 if (skb->destructor)
1412 skb->destructor(skb);
1413 skb->destructor = NULL;
1418 * __skb_queue_purge - empty a list
1419 * @list: list to empty
1421 * Delete all buffers on an &sk_buff list. Each buffer is removed from
1422 * the list and one reference dropped. This function does not take the
1423 * list lock and the caller must hold the relevant locks to use it.
1425 extern void skb_queue_purge(struct sk_buff_head *list);
1426 static inline void __skb_queue_purge(struct sk_buff_head *list)
1428 struct sk_buff *skb;
1429 while ((skb = __skb_dequeue(list)) != NULL)
1434 * __dev_alloc_skb - allocate an skbuff for receiving
1435 * @length: length to allocate
1436 * @gfp_mask: get_free_pages mask, passed to alloc_skb
1438 * Allocate a new &sk_buff and assign it a usage count of one. The
1439 * buffer has unspecified headroom built in. Users should allocate
1440 * the headroom they think they need without accounting for the
1441 * built in space. The built in space is used for optimisations.
1443 * %NULL is returned if there is no free memory.
1445 static inline struct sk_buff *__dev_alloc_skb(unsigned int length,
1448 struct sk_buff *skb = alloc_skb(length + NET_SKB_PAD, gfp_mask);
1450 skb_reserve(skb, NET_SKB_PAD);
1454 extern struct sk_buff *dev_alloc_skb(unsigned int length);
1456 extern struct sk_buff *__netdev_alloc_skb(struct net_device *dev,
1457 unsigned int length, gfp_t gfp_mask);
1460 * netdev_alloc_skb - allocate an skbuff for rx on a specific device
1461 * @dev: network device to receive on
1462 * @length: length to allocate
1464 * Allocate a new &sk_buff and assign it a usage count of one. The
1465 * buffer has unspecified headroom built in. Users should allocate
1466 * the headroom they think they need without accounting for the
1467 * built in space. The built in space is used for optimisations.
1469 * %NULL is returned if there is no free memory. Although this function
1470 * allocates memory it can be called from an interrupt.
1472 static inline struct sk_buff *netdev_alloc_skb(struct net_device *dev,
1473 unsigned int length)
1475 return __netdev_alloc_skb(dev, length, GFP_ATOMIC);
1478 static inline struct sk_buff *netdev_alloc_skb_ip_align(struct net_device *dev,
1479 unsigned int length)
1481 struct sk_buff *skb = netdev_alloc_skb(dev, length + NET_IP_ALIGN);
1483 if (NET_IP_ALIGN && skb)
1484 skb_reserve(skb, NET_IP_ALIGN);
1488 extern struct page *__netdev_alloc_page(struct net_device *dev, gfp_t gfp_mask);
1491 * netdev_alloc_page - allocate a page for ps-rx on a specific device
1492 * @dev: network device to receive on
1494 * Allocate a new page node local to the specified device.
1496 * %NULL is returned if there is no free memory.
1498 static inline struct page *netdev_alloc_page(struct net_device *dev)
1500 return __netdev_alloc_page(dev, GFP_ATOMIC);
1503 static inline void netdev_free_page(struct net_device *dev, struct page *page)
1509 * skb_clone_writable - is the header of a clone writable
1510 * @skb: buffer to check
1511 * @len: length up to which to write
1513 * Returns true if modifying the header part of the cloned buffer
1514 * does not requires the data to be copied.
1516 static inline int skb_clone_writable(struct sk_buff *skb, unsigned int len)
1518 return !skb_header_cloned(skb) &&
1519 skb_headroom(skb) + len <= skb->hdr_len;
1522 static inline int __skb_cow(struct sk_buff *skb, unsigned int headroom,
1527 if (headroom < NET_SKB_PAD)
1528 headroom = NET_SKB_PAD;
1529 if (headroom > skb_headroom(skb))
1530 delta = headroom - skb_headroom(skb);
1532 if (delta || cloned)
1533 return pskb_expand_head(skb, ALIGN(delta, NET_SKB_PAD), 0,
1539 * skb_cow - copy header of skb when it is required
1540 * @skb: buffer to cow
1541 * @headroom: needed headroom
1543 * If the skb passed lacks sufficient headroom or its data part
1544 * is shared, data is reallocated. If reallocation fails, an error
1545 * is returned and original skb is not changed.
1547 * The result is skb with writable area skb->head...skb->tail
1548 * and at least @headroom of space at head.
1550 static inline int skb_cow(struct sk_buff *skb, unsigned int headroom)
1552 return __skb_cow(skb, headroom, skb_cloned(skb));
1556 * skb_cow_head - skb_cow but only making the head writable
1557 * @skb: buffer to cow
1558 * @headroom: needed headroom
1560 * This function is identical to skb_cow except that we replace the
1561 * skb_cloned check by skb_header_cloned. It should be used when
1562 * you only need to push on some header and do not need to modify
1565 static inline int skb_cow_head(struct sk_buff *skb, unsigned int headroom)
1567 return __skb_cow(skb, headroom, skb_header_cloned(skb));
1571 * skb_padto - pad an skbuff up to a minimal size
1572 * @skb: buffer to pad
1573 * @len: minimal length
1575 * Pads up a buffer to ensure the trailing bytes exist and are
1576 * blanked. If the buffer already contains sufficient data it
1577 * is untouched. Otherwise it is extended. Returns zero on
1578 * success. The skb is freed on error.
1581 static inline int skb_padto(struct sk_buff *skb, unsigned int len)
1583 unsigned int size = skb->len;
1584 if (likely(size >= len))
1586 return skb_pad(skb, len - size);
1589 static inline int skb_add_data(struct sk_buff *skb,
1590 char __user *from, int copy)
1592 const int off = skb->len;
1594 if (skb->ip_summed == CHECKSUM_NONE) {
1596 __wsum csum = csum_and_copy_from_user(from, skb_put(skb, copy),
1599 skb->csum = csum_block_add(skb->csum, csum, off);
1602 } else if (!copy_from_user(skb_put(skb, copy), from, copy))
1605 __skb_trim(skb, off);
1609 static inline int skb_can_coalesce(struct sk_buff *skb, int i,
1610 struct page *page, int off)
1613 struct skb_frag_struct *frag = &skb_shinfo(skb)->frags[i - 1];
1615 return page == frag->page &&
1616 off == frag->page_offset + frag->size;
1621 static inline int __skb_linearize(struct sk_buff *skb)
1623 return __pskb_pull_tail(skb, skb->data_len) ? 0 : -ENOMEM;
1627 * skb_linearize - convert paged skb to linear one
1628 * @skb: buffer to linarize
1630 * If there is no free memory -ENOMEM is returned, otherwise zero
1631 * is returned and the old skb data released.
1633 static inline int skb_linearize(struct sk_buff *skb)
1635 return skb_is_nonlinear(skb) ? __skb_linearize(skb) : 0;
1639 * skb_linearize_cow - make sure skb is linear and writable
1640 * @skb: buffer to process
1642 * If there is no free memory -ENOMEM is returned, otherwise zero
1643 * is returned and the old skb data released.
1645 static inline int skb_linearize_cow(struct sk_buff *skb)
1647 return skb_is_nonlinear(skb) || skb_cloned(skb) ?
1648 __skb_linearize(skb) : 0;
1652 * skb_postpull_rcsum - update checksum for received skb after pull
1653 * @skb: buffer to update
1654 * @start: start of data before pull
1655 * @len: length of data pulled
1657 * After doing a pull on a received packet, you need to call this to
1658 * update the CHECKSUM_COMPLETE checksum, or set ip_summed to
1659 * CHECKSUM_NONE so that it can be recomputed from scratch.
1662 static inline void skb_postpull_rcsum(struct sk_buff *skb,
1663 const void *start, unsigned int len)
1665 if (skb->ip_summed == CHECKSUM_COMPLETE)
1666 skb->csum = csum_sub(skb->csum, csum_partial(start, len, 0));
1669 unsigned char *skb_pull_rcsum(struct sk_buff *skb, unsigned int len);
1672 * pskb_trim_rcsum - trim received skb and update checksum
1673 * @skb: buffer to trim
1676 * This is exactly the same as pskb_trim except that it ensures the
1677 * checksum of received packets are still valid after the operation.
1680 static inline int pskb_trim_rcsum(struct sk_buff *skb, unsigned int len)
1682 if (likely(len >= skb->len))
1684 if (skb->ip_summed == CHECKSUM_COMPLETE)
1685 skb->ip_summed = CHECKSUM_NONE;
1686 return __pskb_trim(skb, len);
1689 #define skb_queue_walk(queue, skb) \
1690 for (skb = (queue)->next; \
1691 prefetch(skb->next), (skb != (struct sk_buff *)(queue)); \
1694 #define skb_queue_walk_safe(queue, skb, tmp) \
1695 for (skb = (queue)->next, tmp = skb->next; \
1696 skb != (struct sk_buff *)(queue); \
1697 skb = tmp, tmp = skb->next)
1699 #define skb_queue_walk_from(queue, skb) \
1700 for (; prefetch(skb->next), (skb != (struct sk_buff *)(queue)); \
1703 #define skb_queue_walk_from_safe(queue, skb, tmp) \
1704 for (tmp = skb->next; \
1705 skb != (struct sk_buff *)(queue); \
1706 skb = tmp, tmp = skb->next)
1708 #define skb_queue_reverse_walk(queue, skb) \
1709 for (skb = (queue)->prev; \
1710 prefetch(skb->prev), (skb != (struct sk_buff *)(queue)); \
1714 static inline bool skb_has_frags(const struct sk_buff *skb)
1716 return skb_shinfo(skb)->frag_list != NULL;
1719 static inline void skb_frag_list_init(struct sk_buff *skb)
1721 skb_shinfo(skb)->frag_list = NULL;
1724 static inline void skb_frag_add_head(struct sk_buff *skb, struct sk_buff *frag)
1726 frag->next = skb_shinfo(skb)->frag_list;
1727 skb_shinfo(skb)->frag_list = frag;
1730 #define skb_walk_frags(skb, iter) \
1731 for (iter = skb_shinfo(skb)->frag_list; iter; iter = iter->next)
1733 extern struct sk_buff *__skb_recv_datagram(struct sock *sk, unsigned flags,
1734 int *peeked, int *err);
1735 extern struct sk_buff *skb_recv_datagram(struct sock *sk, unsigned flags,
1736 int noblock, int *err);
1737 extern unsigned int datagram_poll(struct file *file, struct socket *sock,
1738 struct poll_table_struct *wait);
1739 extern int skb_copy_datagram_iovec(const struct sk_buff *from,
1740 int offset, struct iovec *to,
1742 extern int skb_copy_and_csum_datagram_iovec(struct sk_buff *skb,
1745 extern int skb_copy_datagram_from_iovec(struct sk_buff *skb,
1747 const struct iovec *from,
1750 extern int skb_copy_datagram_const_iovec(const struct sk_buff *from,
1752 const struct iovec *to,
1755 extern void skb_free_datagram(struct sock *sk, struct sk_buff *skb);
1756 extern void skb_free_datagram_locked(struct sock *sk,
1757 struct sk_buff *skb);
1758 extern int skb_kill_datagram(struct sock *sk, struct sk_buff *skb,
1759 unsigned int flags);
1760 extern __wsum skb_checksum(const struct sk_buff *skb, int offset,
1761 int len, __wsum csum);
1762 extern int skb_copy_bits(const struct sk_buff *skb, int offset,
1764 extern int skb_store_bits(struct sk_buff *skb, int offset,
1765 const void *from, int len);
1766 extern __wsum skb_copy_and_csum_bits(const struct sk_buff *skb,
1767 int offset, u8 *to, int len,
1769 extern int skb_splice_bits(struct sk_buff *skb,
1770 unsigned int offset,
1771 struct pipe_inode_info *pipe,
1773 unsigned int flags);
1774 extern void skb_copy_and_csum_dev(const struct sk_buff *skb, u8 *to);
1775 extern void skb_split(struct sk_buff *skb,
1776 struct sk_buff *skb1, const u32 len);
1777 extern int skb_shift(struct sk_buff *tgt, struct sk_buff *skb,
1780 extern struct sk_buff *skb_segment(struct sk_buff *skb, int features);
1782 static inline void *skb_header_pointer(const struct sk_buff *skb, int offset,
1783 int len, void *buffer)
1785 int hlen = skb_headlen(skb);
1787 if (hlen - offset >= len)
1788 return skb->data + offset;
1790 if (skb_copy_bits(skb, offset, buffer, len) < 0)
1796 static inline void skb_copy_from_linear_data(const struct sk_buff *skb,
1798 const unsigned int len)
1800 memcpy(to, skb->data, len);
1803 static inline void skb_copy_from_linear_data_offset(const struct sk_buff *skb,
1804 const int offset, void *to,
1805 const unsigned int len)
1807 memcpy(to, skb->data + offset, len);
1810 static inline void skb_copy_to_linear_data(struct sk_buff *skb,
1812 const unsigned int len)
1814 memcpy(skb->data, from, len);
1817 static inline void skb_copy_to_linear_data_offset(struct sk_buff *skb,
1820 const unsigned int len)
1822 memcpy(skb->data + offset, from, len);
1825 extern void skb_init(void);
1827 static inline ktime_t skb_get_ktime(const struct sk_buff *skb)
1833 * skb_get_timestamp - get timestamp from a skb
1834 * @skb: skb to get stamp from
1835 * @stamp: pointer to struct timeval to store stamp in
1837 * Timestamps are stored in the skb as offsets to a base timestamp.
1838 * This function converts the offset back to a struct timeval and stores
1841 static inline void skb_get_timestamp(const struct sk_buff *skb,
1842 struct timeval *stamp)
1844 *stamp = ktime_to_timeval(skb->tstamp);
1847 static inline void skb_get_timestampns(const struct sk_buff *skb,
1848 struct timespec *stamp)
1850 *stamp = ktime_to_timespec(skb->tstamp);
1853 static inline void __net_timestamp(struct sk_buff *skb)
1855 skb->tstamp = ktime_get_real();
1858 static inline ktime_t net_timedelta(ktime_t t)
1860 return ktime_sub(ktime_get_real(), t);
1863 static inline ktime_t net_invalid_timestamp(void)
1865 return ktime_set(0, 0);
1869 * skb_tstamp_tx - queue clone of skb with send time stamps
1870 * @orig_skb: the original outgoing packet
1871 * @hwtstamps: hardware time stamps, may be NULL if not available
1873 * If the skb has a socket associated, then this function clones the
1874 * skb (thus sharing the actual data and optional structures), stores
1875 * the optional hardware time stamping information (if non NULL) or
1876 * generates a software time stamp (otherwise), then queues the clone
1877 * to the error queue of the socket. Errors are silently ignored.
1879 extern void skb_tstamp_tx(struct sk_buff *orig_skb,
1880 struct skb_shared_hwtstamps *hwtstamps);
1882 extern __sum16 __skb_checksum_complete_head(struct sk_buff *skb, int len);
1883 extern __sum16 __skb_checksum_complete(struct sk_buff *skb);
1885 static inline int skb_csum_unnecessary(const struct sk_buff *skb)
1887 return skb->ip_summed & CHECKSUM_UNNECESSARY;
1891 * skb_checksum_complete - Calculate checksum of an entire packet
1892 * @skb: packet to process
1894 * This function calculates the checksum over the entire packet plus
1895 * the value of skb->csum. The latter can be used to supply the
1896 * checksum of a pseudo header as used by TCP/UDP. It returns the
1899 * For protocols that contain complete checksums such as ICMP/TCP/UDP,
1900 * this function can be used to verify that checksum on received
1901 * packets. In that case the function should return zero if the
1902 * checksum is correct. In particular, this function will return zero
1903 * if skb->ip_summed is CHECKSUM_UNNECESSARY which indicates that the
1904 * hardware has already verified the correctness of the checksum.
1906 static inline __sum16 skb_checksum_complete(struct sk_buff *skb)
1908 return skb_csum_unnecessary(skb) ?
1909 0 : __skb_checksum_complete(skb);
1912 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
1913 extern void nf_conntrack_destroy(struct nf_conntrack *nfct);
1914 static inline void nf_conntrack_put(struct nf_conntrack *nfct)
1916 if (nfct && atomic_dec_and_test(&nfct->use))
1917 nf_conntrack_destroy(nfct);
1919 static inline void nf_conntrack_get(struct nf_conntrack *nfct)
1922 atomic_inc(&nfct->use);
1924 static inline void nf_conntrack_get_reasm(struct sk_buff *skb)
1927 atomic_inc(&skb->users);
1929 static inline void nf_conntrack_put_reasm(struct sk_buff *skb)
1935 #ifdef CONFIG_BRIDGE_NETFILTER
1936 static inline void nf_bridge_put(struct nf_bridge_info *nf_bridge)
1938 if (nf_bridge && atomic_dec_and_test(&nf_bridge->use))
1941 static inline void nf_bridge_get(struct nf_bridge_info *nf_bridge)
1944 atomic_inc(&nf_bridge->use);
1946 #endif /* CONFIG_BRIDGE_NETFILTER */
1947 static inline void nf_reset(struct sk_buff *skb)
1949 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
1950 nf_conntrack_put(skb->nfct);
1952 nf_conntrack_put_reasm(skb->nfct_reasm);
1953 skb->nfct_reasm = NULL;
1955 #ifdef CONFIG_BRIDGE_NETFILTER
1956 nf_bridge_put(skb->nf_bridge);
1957 skb->nf_bridge = NULL;
1961 /* Note: This doesn't put any conntrack and bridge info in dst. */
1962 static inline void __nf_copy(struct sk_buff *dst, const struct sk_buff *src)
1964 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
1965 dst->nfct = src->nfct;
1966 nf_conntrack_get(src->nfct);
1967 dst->nfctinfo = src->nfctinfo;
1968 dst->nfct_reasm = src->nfct_reasm;
1969 nf_conntrack_get_reasm(src->nfct_reasm);
1971 #ifdef CONFIG_BRIDGE_NETFILTER
1972 dst->nf_bridge = src->nf_bridge;
1973 nf_bridge_get(src->nf_bridge);
1977 static inline void nf_copy(struct sk_buff *dst, const struct sk_buff *src)
1979 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
1980 nf_conntrack_put(dst->nfct);
1981 nf_conntrack_put_reasm(dst->nfct_reasm);
1983 #ifdef CONFIG_BRIDGE_NETFILTER
1984 nf_bridge_put(dst->nf_bridge);
1986 __nf_copy(dst, src);
1989 #ifdef CONFIG_NETWORK_SECMARK
1990 static inline void skb_copy_secmark(struct sk_buff *to, const struct sk_buff *from)
1992 to->secmark = from->secmark;
1995 static inline void skb_init_secmark(struct sk_buff *skb)
2000 static inline void skb_copy_secmark(struct sk_buff *to, const struct sk_buff *from)
2003 static inline void skb_init_secmark(struct sk_buff *skb)
2007 static inline void skb_set_queue_mapping(struct sk_buff *skb, u16 queue_mapping)
2009 skb->queue_mapping = queue_mapping;
2012 static inline u16 skb_get_queue_mapping(const struct sk_buff *skb)
2014 return skb->queue_mapping;
2017 static inline void skb_copy_queue_mapping(struct sk_buff *to, const struct sk_buff *from)
2019 to->queue_mapping = from->queue_mapping;
2022 static inline void skb_record_rx_queue(struct sk_buff *skb, u16 rx_queue)
2024 skb->queue_mapping = rx_queue + 1;
2027 static inline u16 skb_get_rx_queue(const struct sk_buff *skb)
2029 return skb->queue_mapping - 1;
2032 static inline bool skb_rx_queue_recorded(const struct sk_buff *skb)
2034 return (skb->queue_mapping != 0);
2037 extern u16 skb_tx_hash(const struct net_device *dev,
2038 const struct sk_buff *skb);
2041 static inline struct sec_path *skb_sec_path(struct sk_buff *skb)
2046 static inline struct sec_path *skb_sec_path(struct sk_buff *skb)
2052 static inline int skb_is_gso(const struct sk_buff *skb)
2054 return skb_shinfo(skb)->gso_size;
2057 static inline int skb_is_gso_v6(const struct sk_buff *skb)
2059 return skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6;
2062 extern void __skb_warn_lro_forwarding(const struct sk_buff *skb);
2064 static inline bool skb_warn_if_lro(const struct sk_buff *skb)
2066 /* LRO sets gso_size but not gso_type, whereas if GSO is really
2067 * wanted then gso_type will be set. */
2068 struct skb_shared_info *shinfo = skb_shinfo(skb);
2069 if (shinfo->gso_size != 0 && unlikely(shinfo->gso_type == 0)) {
2070 __skb_warn_lro_forwarding(skb);
2076 static inline void skb_forward_csum(struct sk_buff *skb)
2078 /* Unfortunately we don't support this one. Any brave souls? */
2079 if (skb->ip_summed == CHECKSUM_COMPLETE)
2080 skb->ip_summed = CHECKSUM_NONE;
2083 bool skb_partial_csum_set(struct sk_buff *skb, u16 start, u16 off);
2084 #endif /* __KERNEL__ */
2085 #endif /* _LINUX_SKBUFF_H */