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 <linux/atomic.h>
24 #include <asm/types.h>
25 #include <linux/spinlock.h>
26 #include <linux/net.h>
27 #include <linux/textsearch.h>
28 #include <net/checksum.h>
29 #include <linux/rcupdate.h>
30 #include <linux/dmaengine.h>
31 #include <linux/hrtimer.h>
32 #include <linux/dma-mapping.h>
34 /* Don't change this without changing skb_csum_unnecessary! */
35 #define CHECKSUM_NONE 0
36 #define CHECKSUM_UNNECESSARY 1
37 #define CHECKSUM_COMPLETE 2
38 #define CHECKSUM_PARTIAL 3
40 #define SKB_DATA_ALIGN(X) (((X) + (SMP_CACHE_BYTES - 1)) & \
41 ~(SMP_CACHE_BYTES - 1))
42 #define SKB_WITH_OVERHEAD(X) \
43 ((X) - SKB_DATA_ALIGN(sizeof(struct skb_shared_info)))
44 #define SKB_MAX_ORDER(X, ORDER) \
45 SKB_WITH_OVERHEAD((PAGE_SIZE << (ORDER)) - (X))
46 #define SKB_MAX_HEAD(X) (SKB_MAX_ORDER((X), 0))
47 #define SKB_MAX_ALLOC (SKB_MAX_ORDER(0, 2))
49 /* return minimum truesize of one skb containing X bytes of data */
50 #define SKB_TRUESIZE(X) ((X) + \
51 SKB_DATA_ALIGN(sizeof(struct sk_buff)) + \
52 SKB_DATA_ALIGN(sizeof(struct skb_shared_info)))
54 /* A. Checksumming of received packets by device.
56 * NONE: device failed to checksum this packet.
57 * skb->csum is undefined.
59 * UNNECESSARY: device parsed packet and wouldbe verified checksum.
60 * skb->csum is undefined.
61 * It is bad option, but, unfortunately, many of vendors do this.
62 * Apparently with secret goal to sell you new device, when you
63 * will add new protocol to your host. F.e. IPv6. 8)
65 * COMPLETE: the most generic way. Device supplied checksum of _all_
66 * the packet as seen by netif_rx in skb->csum.
67 * NOTE: Even if device supports only some protocols, but
68 * is able to produce some skb->csum, it MUST use COMPLETE,
71 * PARTIAL: identical to the case for output below. This may occur
72 * on a packet received directly from another Linux OS, e.g.,
73 * a virtualised Linux kernel on the same host. The packet can
74 * be treated in the same way as UNNECESSARY except that on
75 * output (i.e., forwarding) the checksum must be filled in
76 * by the OS or the hardware.
78 * B. Checksumming on output.
80 * NONE: skb is checksummed by protocol or csum is not required.
82 * PARTIAL: device is required to csum packet as seen by hard_start_xmit
83 * from skb->csum_start to the end and to record the checksum
84 * at skb->csum_start + skb->csum_offset.
86 * Device must show its capabilities in dev->features, set
87 * at device setup time.
88 * NETIF_F_HW_CSUM - it is clever device, it is able to checksum
90 * NETIF_F_NO_CSUM - loopback or reliable single hop media.
91 * NETIF_F_IP_CSUM - device is dumb. It is able to csum only
92 * TCP/UDP over IPv4. Sigh. Vendors like this
93 * way by an unknown reason. Though, see comment above
94 * about CHECKSUM_UNNECESSARY. 8)
95 * NETIF_F_IPV6_CSUM about as dumb as the last one but does IPv6 instead.
97 * Any questions? No questions, good. --ANK
102 struct pipe_inode_info;
104 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
105 struct nf_conntrack {
110 #ifdef CONFIG_BRIDGE_NETFILTER
111 struct nf_bridge_info {
113 struct net_device *physindev;
114 struct net_device *physoutdev;
116 unsigned long data[32 / sizeof(unsigned long)];
120 struct sk_buff_head {
121 /* These two members must be first. */
122 struct sk_buff *next;
123 struct sk_buff *prev;
131 /* To allow 64K frame to be packed as single skb without frag_list. Since
132 * GRO uses frags we allocate at least 16 regardless of page size.
134 #if (65536/PAGE_SIZE + 2) < 16
135 #define MAX_SKB_FRAGS 16UL
137 #define MAX_SKB_FRAGS (65536/PAGE_SIZE + 2)
140 typedef struct skb_frag_struct skb_frag_t;
142 struct skb_frag_struct {
146 #if (BITS_PER_LONG > 32) || (PAGE_SIZE >= 65536)
155 static inline unsigned int skb_frag_size(const skb_frag_t *frag)
160 static inline void skb_frag_size_set(skb_frag_t *frag, unsigned int size)
165 static inline void skb_frag_size_add(skb_frag_t *frag, int delta)
170 static inline void skb_frag_size_sub(skb_frag_t *frag, int delta)
175 #define HAVE_HW_TIME_STAMP
178 * struct skb_shared_hwtstamps - hardware time stamps
179 * @hwtstamp: hardware time stamp transformed into duration
180 * since arbitrary point in time
181 * @syststamp: hwtstamp transformed to system time base
183 * Software time stamps generated by ktime_get_real() are stored in
184 * skb->tstamp. The relation between the different kinds of time
185 * stamps is as follows:
187 * syststamp and tstamp can be compared against each other in
188 * arbitrary combinations. The accuracy of a
189 * syststamp/tstamp/"syststamp from other device" comparison is
190 * limited by the accuracy of the transformation into system time
191 * base. This depends on the device driver and its underlying
194 * hwtstamps can only be compared against other hwtstamps from
197 * This structure is attached to packets as part of the
198 * &skb_shared_info. Use skb_hwtstamps() to get a pointer.
200 struct skb_shared_hwtstamps {
205 /* Definitions for tx_flags in struct skb_shared_info */
207 /* generate hardware time stamp */
208 SKBTX_HW_TSTAMP = 1 << 0,
210 /* generate software time stamp */
211 SKBTX_SW_TSTAMP = 1 << 1,
213 /* device driver is going to provide hardware time stamp */
214 SKBTX_IN_PROGRESS = 1 << 2,
216 /* ensure the originating sk reference is available on driver level */
217 SKBTX_DRV_NEEDS_SK_REF = 1 << 3,
219 /* device driver supports TX zero-copy buffers */
220 SKBTX_DEV_ZEROCOPY = 1 << 4,
224 * The callback notifies userspace to release buffers when skb DMA is done in
225 * lower device, the skb last reference should be 0 when calling this.
226 * The desc is used to track userspace buffer index.
229 void (*callback)(void *);
234 /* This data is invariant across clones and lives at
235 * the end of the header data, ie. at skb->end.
237 struct skb_shared_info {
238 unsigned short nr_frags;
239 unsigned short gso_size;
240 /* Warning: this field is not always filled in (UFO)! */
241 unsigned short gso_segs;
242 unsigned short gso_type;
245 struct sk_buff *frag_list;
246 struct skb_shared_hwtstamps hwtstamps;
249 * Warning : all fields before dataref are cleared in __alloc_skb()
253 /* Intermediate layers must ensure that destructor_arg
254 * remains valid until skb destructor */
255 void * destructor_arg;
257 /* must be last field, see pskb_expand_head() */
258 skb_frag_t frags[MAX_SKB_FRAGS];
261 /* We divide dataref into two halves. The higher 16 bits hold references
262 * to the payload part of skb->data. The lower 16 bits hold references to
263 * the entire skb->data. A clone of a headerless skb holds the length of
264 * the header in skb->hdr_len.
266 * All users must obey the rule that the skb->data reference count must be
267 * greater than or equal to the payload reference count.
269 * Holding a reference to the payload part means that the user does not
270 * care about modifications to the header part of skb->data.
272 #define SKB_DATAREF_SHIFT 16
273 #define SKB_DATAREF_MASK ((1 << SKB_DATAREF_SHIFT) - 1)
277 SKB_FCLONE_UNAVAILABLE,
283 SKB_GSO_TCPV4 = 1 << 0,
284 SKB_GSO_UDP = 1 << 1,
286 /* This indicates the skb is from an untrusted source. */
287 SKB_GSO_DODGY = 1 << 2,
289 /* This indicates the tcp segment has CWR set. */
290 SKB_GSO_TCP_ECN = 1 << 3,
292 SKB_GSO_TCPV6 = 1 << 4,
294 SKB_GSO_FCOE = 1 << 5,
297 #if BITS_PER_LONG > 32
298 #define NET_SKBUFF_DATA_USES_OFFSET 1
301 #ifdef NET_SKBUFF_DATA_USES_OFFSET
302 typedef unsigned int sk_buff_data_t;
304 typedef unsigned char *sk_buff_data_t;
307 #if defined(CONFIG_NF_DEFRAG_IPV4) || defined(CONFIG_NF_DEFRAG_IPV4_MODULE) || \
308 defined(CONFIG_NF_DEFRAG_IPV6) || defined(CONFIG_NF_DEFRAG_IPV6_MODULE)
309 #define NET_SKBUFF_NF_DEFRAG_NEEDED 1
313 * struct sk_buff - socket buffer
314 * @next: Next buffer in list
315 * @prev: Previous buffer in list
316 * @tstamp: Time we arrived
317 * @sk: Socket we are owned by
318 * @dev: Device we arrived on/are leaving by
319 * @cb: Control buffer. Free for use by every layer. Put private vars here
320 * @_skb_refdst: destination entry (with norefcount bit)
321 * @sp: the security path, used for xfrm
322 * @len: Length of actual data
323 * @data_len: Data length
324 * @mac_len: Length of link layer header
325 * @hdr_len: writable header length of cloned skb
326 * @csum: Checksum (must include start/offset pair)
327 * @csum_start: Offset from skb->head where checksumming should start
328 * @csum_offset: Offset from csum_start where checksum should be stored
329 * @priority: Packet queueing priority
330 * @local_df: allow local fragmentation
331 * @cloned: Head may be cloned (check refcnt to be sure)
332 * @ip_summed: Driver fed us an IP checksum
333 * @nohdr: Payload reference only, must not modify header
334 * @nfctinfo: Relationship of this skb to the connection
335 * @pkt_type: Packet class
336 * @fclone: skbuff clone status
337 * @ipvs_property: skbuff is owned by ipvs
338 * @peeked: this packet has been seen already, so stats have been
339 * done for it, don't do them again
340 * @nf_trace: netfilter packet trace flag
341 * @protocol: Packet protocol from driver
342 * @destructor: Destruct function
343 * @nfct: Associated connection, if any
344 * @nfct_reasm: netfilter conntrack re-assembly pointer
345 * @nf_bridge: Saved data about a bridged frame - see br_netfilter.c
346 * @skb_iif: ifindex of device we arrived on
347 * @tc_index: Traffic control index
348 * @tc_verd: traffic control verdict
349 * @rxhash: the packet hash computed on receive
350 * @queue_mapping: Queue mapping for multiqueue devices
351 * @ndisc_nodetype: router type (from link layer)
352 * @ooo_okay: allow the mapping of a socket to a queue to be changed
353 * @l4_rxhash: indicate rxhash is a canonical 4-tuple hash over transport
355 * @dma_cookie: a cookie to one of several possible DMA operations
356 * done by skb DMA functions
357 * @secmark: security marking
358 * @mark: Generic packet mark
359 * @dropcount: total number of sk_receive_queue overflows
360 * @vlan_tci: vlan tag control information
361 * @transport_header: Transport layer header
362 * @network_header: Network layer header
363 * @mac_header: Link layer header
364 * @tail: Tail pointer
366 * @head: Head of buffer
367 * @data: Data head pointer
368 * @truesize: Buffer size
369 * @users: User count - see {datagram,tcp}.c
373 /* These two members must be first. */
374 struct sk_buff *next;
375 struct sk_buff *prev;
380 struct net_device *dev;
383 * This is the control buffer. It is free to use for every
384 * layer. Please put your private variables there. If you
385 * want to keep them across layers you have to do a skb_clone()
386 * first. This is owned by whoever has the skb queued ATM.
388 char cb[48] __aligned(8);
390 unsigned long _skb_refdst;
406 kmemcheck_bitfield_begin(flags1);
417 kmemcheck_bitfield_end(flags1);
420 void (*destructor)(struct sk_buff *skb);
421 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
422 struct nf_conntrack *nfct;
424 #ifdef NET_SKBUFF_NF_DEFRAG_NEEDED
425 struct sk_buff *nfct_reasm;
427 #ifdef CONFIG_BRIDGE_NETFILTER
428 struct nf_bridge_info *nf_bridge;
432 #ifdef CONFIG_NET_SCHED
433 __u16 tc_index; /* traffic control index */
434 #ifdef CONFIG_NET_CLS_ACT
435 __u16 tc_verd; /* traffic control verdict */
442 kmemcheck_bitfield_begin(flags2);
443 #ifdef CONFIG_IPV6_NDISC_NODETYPE
444 __u8 ndisc_nodetype:2;
448 kmemcheck_bitfield_end(flags2);
452 #ifdef CONFIG_NET_DMA
453 dma_cookie_t dma_cookie;
455 #ifdef CONFIG_NETWORK_SECMARK
465 sk_buff_data_t transport_header;
466 sk_buff_data_t network_header;
467 sk_buff_data_t mac_header;
468 /* These elements must be at the end, see alloc_skb() for details. */
473 unsigned int truesize;
479 * Handling routines are only of interest to the kernel
481 #include <linux/slab.h>
483 #include <asm/system.h>
486 * skb might have a dst pointer attached, refcounted or not.
487 * _skb_refdst low order bit is set if refcount was _not_ taken
489 #define SKB_DST_NOREF 1UL
490 #define SKB_DST_PTRMASK ~(SKB_DST_NOREF)
493 * skb_dst - returns skb dst_entry
496 * Returns skb dst_entry, regardless of reference taken or not.
498 static inline struct dst_entry *skb_dst(const struct sk_buff *skb)
500 /* If refdst was not refcounted, check we still are in a
501 * rcu_read_lock section
503 WARN_ON((skb->_skb_refdst & SKB_DST_NOREF) &&
504 !rcu_read_lock_held() &&
505 !rcu_read_lock_bh_held());
506 return (struct dst_entry *)(skb->_skb_refdst & SKB_DST_PTRMASK);
510 * skb_dst_set - sets skb dst
514 * Sets skb dst, assuming a reference was taken on dst and should
515 * be released by skb_dst_drop()
517 static inline void skb_dst_set(struct sk_buff *skb, struct dst_entry *dst)
519 skb->_skb_refdst = (unsigned long)dst;
522 extern void skb_dst_set_noref(struct sk_buff *skb, struct dst_entry *dst);
525 * skb_dst_is_noref - Test if skb dst isn't refcounted
528 static inline bool skb_dst_is_noref(const struct sk_buff *skb)
530 return (skb->_skb_refdst & SKB_DST_NOREF) && skb_dst(skb);
533 static inline struct rtable *skb_rtable(const struct sk_buff *skb)
535 return (struct rtable *)skb_dst(skb);
538 extern void kfree_skb(struct sk_buff *skb);
539 extern void consume_skb(struct sk_buff *skb);
540 extern void __kfree_skb(struct sk_buff *skb);
541 extern struct sk_buff *__alloc_skb(unsigned int size,
542 gfp_t priority, int fclone, int node);
543 static inline struct sk_buff *alloc_skb(unsigned int size,
546 return __alloc_skb(size, priority, 0, NUMA_NO_NODE);
549 static inline struct sk_buff *alloc_skb_fclone(unsigned int size,
552 return __alloc_skb(size, priority, 1, NUMA_NO_NODE);
555 extern void skb_recycle(struct sk_buff *skb);
556 extern bool skb_recycle_check(struct sk_buff *skb, int skb_size);
558 extern struct sk_buff *skb_morph(struct sk_buff *dst, struct sk_buff *src);
559 extern int skb_copy_ubufs(struct sk_buff *skb, gfp_t gfp_mask);
560 extern struct sk_buff *skb_clone(struct sk_buff *skb,
562 extern struct sk_buff *skb_copy(const struct sk_buff *skb,
564 extern struct sk_buff *pskb_copy(struct sk_buff *skb,
566 extern int pskb_expand_head(struct sk_buff *skb,
567 int nhead, int ntail,
569 extern struct sk_buff *skb_realloc_headroom(struct sk_buff *skb,
570 unsigned int headroom);
571 extern struct sk_buff *skb_copy_expand(const struct sk_buff *skb,
572 int newheadroom, int newtailroom,
574 extern int skb_to_sgvec(struct sk_buff *skb,
575 struct scatterlist *sg, int offset,
577 extern int skb_cow_data(struct sk_buff *skb, int tailbits,
578 struct sk_buff **trailer);
579 extern int skb_pad(struct sk_buff *skb, int pad);
580 #define dev_kfree_skb(a) consume_skb(a)
582 extern int skb_append_datato_frags(struct sock *sk, struct sk_buff *skb,
583 int getfrag(void *from, char *to, int offset,
584 int len,int odd, struct sk_buff *skb),
585 void *from, int length);
587 struct skb_seq_state {
591 __u32 stepped_offset;
592 struct sk_buff *root_skb;
593 struct sk_buff *cur_skb;
597 extern void skb_prepare_seq_read(struct sk_buff *skb,
598 unsigned int from, unsigned int to,
599 struct skb_seq_state *st);
600 extern unsigned int skb_seq_read(unsigned int consumed, const u8 **data,
601 struct skb_seq_state *st);
602 extern void skb_abort_seq_read(struct skb_seq_state *st);
604 extern unsigned int skb_find_text(struct sk_buff *skb, unsigned int from,
605 unsigned int to, struct ts_config *config,
606 struct ts_state *state);
608 extern void __skb_get_rxhash(struct sk_buff *skb);
609 static inline __u32 skb_get_rxhash(struct sk_buff *skb)
612 __skb_get_rxhash(skb);
617 #ifdef NET_SKBUFF_DATA_USES_OFFSET
618 static inline unsigned char *skb_end_pointer(const struct sk_buff *skb)
620 return skb->head + skb->end;
623 static inline unsigned char *skb_end_pointer(const struct sk_buff *skb)
630 #define skb_shinfo(SKB) ((struct skb_shared_info *)(skb_end_pointer(SKB)))
632 static inline struct skb_shared_hwtstamps *skb_hwtstamps(struct sk_buff *skb)
634 return &skb_shinfo(skb)->hwtstamps;
638 * skb_queue_empty - check if a queue is empty
641 * Returns true if the queue is empty, false otherwise.
643 static inline int skb_queue_empty(const struct sk_buff_head *list)
645 return list->next == (struct sk_buff *)list;
649 * skb_queue_is_last - check if skb is the last entry in the queue
653 * Returns true if @skb is the last buffer on the list.
655 static inline bool skb_queue_is_last(const struct sk_buff_head *list,
656 const struct sk_buff *skb)
658 return skb->next == (struct sk_buff *)list;
662 * skb_queue_is_first - check if skb is the first entry in the queue
666 * Returns true if @skb is the first buffer on the list.
668 static inline bool skb_queue_is_first(const struct sk_buff_head *list,
669 const struct sk_buff *skb)
671 return skb->prev == (struct sk_buff *)list;
675 * skb_queue_next - return the next packet in the queue
677 * @skb: current buffer
679 * Return the next packet in @list after @skb. It is only valid to
680 * call this if skb_queue_is_last() evaluates to false.
682 static inline struct sk_buff *skb_queue_next(const struct sk_buff_head *list,
683 const struct sk_buff *skb)
685 /* This BUG_ON may seem severe, but if we just return then we
686 * are going to dereference garbage.
688 BUG_ON(skb_queue_is_last(list, skb));
693 * skb_queue_prev - return the prev packet in the queue
695 * @skb: current buffer
697 * Return the prev packet in @list before @skb. It is only valid to
698 * call this if skb_queue_is_first() evaluates to false.
700 static inline struct sk_buff *skb_queue_prev(const struct sk_buff_head *list,
701 const struct sk_buff *skb)
703 /* This BUG_ON may seem severe, but if we just return then we
704 * are going to dereference garbage.
706 BUG_ON(skb_queue_is_first(list, skb));
711 * skb_get - reference buffer
712 * @skb: buffer to reference
714 * Makes another reference to a socket buffer and returns a pointer
717 static inline struct sk_buff *skb_get(struct sk_buff *skb)
719 atomic_inc(&skb->users);
724 * If users == 1, we are the only owner and are can avoid redundant
729 * skb_cloned - is the buffer a clone
730 * @skb: buffer to check
732 * Returns true if the buffer was generated with skb_clone() and is
733 * one of multiple shared copies of the buffer. Cloned buffers are
734 * shared data so must not be written to under normal circumstances.
736 static inline int skb_cloned(const struct sk_buff *skb)
738 return skb->cloned &&
739 (atomic_read(&skb_shinfo(skb)->dataref) & SKB_DATAREF_MASK) != 1;
743 * skb_header_cloned - is the header a clone
744 * @skb: buffer to check
746 * Returns true if modifying the header part of the buffer requires
747 * the data to be copied.
749 static inline int skb_header_cloned(const struct sk_buff *skb)
756 dataref = atomic_read(&skb_shinfo(skb)->dataref);
757 dataref = (dataref & SKB_DATAREF_MASK) - (dataref >> SKB_DATAREF_SHIFT);
762 * skb_header_release - release reference to header
763 * @skb: buffer to operate on
765 * Drop a reference to the header part of the buffer. This is done
766 * by acquiring a payload reference. You must not read from the header
767 * part of skb->data after this.
769 static inline void skb_header_release(struct sk_buff *skb)
773 atomic_add(1 << SKB_DATAREF_SHIFT, &skb_shinfo(skb)->dataref);
777 * skb_shared - is the buffer shared
778 * @skb: buffer to check
780 * Returns true if more than one person has a reference to this
783 static inline int skb_shared(const struct sk_buff *skb)
785 return atomic_read(&skb->users) != 1;
789 * skb_share_check - check if buffer is shared and if so clone it
790 * @skb: buffer to check
791 * @pri: priority for memory allocation
793 * If the buffer is shared the buffer is cloned and the old copy
794 * drops a reference. A new clone with a single reference is returned.
795 * If the buffer is not shared the original buffer is returned. When
796 * being called from interrupt status or with spinlocks held pri must
799 * NULL is returned on a memory allocation failure.
801 static inline struct sk_buff *skb_share_check(struct sk_buff *skb,
804 might_sleep_if(pri & __GFP_WAIT);
805 if (skb_shared(skb)) {
806 struct sk_buff *nskb = skb_clone(skb, pri);
814 * Copy shared buffers into a new sk_buff. We effectively do COW on
815 * packets to handle cases where we have a local reader and forward
816 * and a couple of other messy ones. The normal one is tcpdumping
817 * a packet thats being forwarded.
821 * skb_unshare - make a copy of a shared buffer
822 * @skb: buffer to check
823 * @pri: priority for memory allocation
825 * If the socket buffer is a clone then this function creates a new
826 * copy of the data, drops a reference count on the old copy and returns
827 * the new copy with the reference count at 1. If the buffer is not a clone
828 * the original buffer is returned. When called with a spinlock held or
829 * from interrupt state @pri must be %GFP_ATOMIC
831 * %NULL is returned on a memory allocation failure.
833 static inline struct sk_buff *skb_unshare(struct sk_buff *skb,
836 might_sleep_if(pri & __GFP_WAIT);
837 if (skb_cloned(skb)) {
838 struct sk_buff *nskb = skb_copy(skb, pri);
839 kfree_skb(skb); /* Free our shared copy */
846 * skb_peek - peek at the head of an &sk_buff_head
847 * @list_: list to peek at
849 * Peek an &sk_buff. Unlike most other operations you _MUST_
850 * be careful with this one. A peek leaves the buffer on the
851 * list and someone else may run off with it. You must hold
852 * the appropriate locks or have a private queue to do this.
854 * Returns %NULL for an empty list or a pointer to the head element.
855 * The reference count is not incremented and the reference is therefore
856 * volatile. Use with caution.
858 static inline struct sk_buff *skb_peek(const struct sk_buff_head *list_)
860 struct sk_buff *list = ((const struct sk_buff *)list_)->next;
861 if (list == (struct sk_buff *)list_)
867 * skb_peek_tail - peek at the tail of an &sk_buff_head
868 * @list_: list to peek at
870 * Peek an &sk_buff. Unlike most other operations you _MUST_
871 * be careful with this one. A peek leaves the buffer on the
872 * list and someone else may run off with it. You must hold
873 * the appropriate locks or have a private queue to do this.
875 * Returns %NULL for an empty list or a pointer to the tail element.
876 * The reference count is not incremented and the reference is therefore
877 * volatile. Use with caution.
879 static inline struct sk_buff *skb_peek_tail(const struct sk_buff_head *list_)
881 struct sk_buff *list = ((const struct sk_buff *)list_)->prev;
882 if (list == (struct sk_buff *)list_)
888 * skb_queue_len - get queue length
889 * @list_: list to measure
891 * Return the length of an &sk_buff queue.
893 static inline __u32 skb_queue_len(const struct sk_buff_head *list_)
899 * __skb_queue_head_init - initialize non-spinlock portions of sk_buff_head
900 * @list: queue to initialize
902 * This initializes only the list and queue length aspects of
903 * an sk_buff_head object. This allows to initialize the list
904 * aspects of an sk_buff_head without reinitializing things like
905 * the spinlock. It can also be used for on-stack sk_buff_head
906 * objects where the spinlock is known to not be used.
908 static inline void __skb_queue_head_init(struct sk_buff_head *list)
910 list->prev = list->next = (struct sk_buff *)list;
915 * This function creates a split out lock class for each invocation;
916 * this is needed for now since a whole lot of users of the skb-queue
917 * infrastructure in drivers have different locking usage (in hardirq)
918 * than the networking core (in softirq only). In the long run either the
919 * network layer or drivers should need annotation to consolidate the
920 * main types of usage into 3 classes.
922 static inline void skb_queue_head_init(struct sk_buff_head *list)
924 spin_lock_init(&list->lock);
925 __skb_queue_head_init(list);
928 static inline void skb_queue_head_init_class(struct sk_buff_head *list,
929 struct lock_class_key *class)
931 skb_queue_head_init(list);
932 lockdep_set_class(&list->lock, class);
936 * Insert an sk_buff on a list.
938 * The "__skb_xxxx()" functions are the non-atomic ones that
939 * can only be called with interrupts disabled.
941 extern void skb_insert(struct sk_buff *old, struct sk_buff *newsk, struct sk_buff_head *list);
942 static inline void __skb_insert(struct sk_buff *newsk,
943 struct sk_buff *prev, struct sk_buff *next,
944 struct sk_buff_head *list)
948 next->prev = prev->next = newsk;
952 static inline void __skb_queue_splice(const struct sk_buff_head *list,
953 struct sk_buff *prev,
954 struct sk_buff *next)
956 struct sk_buff *first = list->next;
957 struct sk_buff *last = list->prev;
967 * skb_queue_splice - join two skb lists, this is designed for stacks
968 * @list: the new list to add
969 * @head: the place to add it in the first list
971 static inline void skb_queue_splice(const struct sk_buff_head *list,
972 struct sk_buff_head *head)
974 if (!skb_queue_empty(list)) {
975 __skb_queue_splice(list, (struct sk_buff *) head, head->next);
976 head->qlen += list->qlen;
981 * skb_queue_splice - join two skb lists and reinitialise the emptied list
982 * @list: the new list to add
983 * @head: the place to add it in the first list
985 * The list at @list is reinitialised
987 static inline void skb_queue_splice_init(struct sk_buff_head *list,
988 struct sk_buff_head *head)
990 if (!skb_queue_empty(list)) {
991 __skb_queue_splice(list, (struct sk_buff *) head, head->next);
992 head->qlen += list->qlen;
993 __skb_queue_head_init(list);
998 * skb_queue_splice_tail - join two skb lists, each list being a queue
999 * @list: the new list to add
1000 * @head: the place to add it in the first list
1002 static inline void skb_queue_splice_tail(const struct sk_buff_head *list,
1003 struct sk_buff_head *head)
1005 if (!skb_queue_empty(list)) {
1006 __skb_queue_splice(list, head->prev, (struct sk_buff *) head);
1007 head->qlen += list->qlen;
1012 * skb_queue_splice_tail - join two skb lists and reinitialise the emptied list
1013 * @list: the new list to add
1014 * @head: the place to add it in the first list
1016 * Each of the lists is a queue.
1017 * The list at @list is reinitialised
1019 static inline void skb_queue_splice_tail_init(struct sk_buff_head *list,
1020 struct sk_buff_head *head)
1022 if (!skb_queue_empty(list)) {
1023 __skb_queue_splice(list, head->prev, (struct sk_buff *) head);
1024 head->qlen += list->qlen;
1025 __skb_queue_head_init(list);
1030 * __skb_queue_after - queue a buffer at the list head
1031 * @list: list to use
1032 * @prev: place after this buffer
1033 * @newsk: buffer to queue
1035 * Queue a buffer int the middle of a list. This function takes no locks
1036 * and you must therefore hold required locks before calling it.
1038 * A buffer cannot be placed on two lists at the same time.
1040 static inline void __skb_queue_after(struct sk_buff_head *list,
1041 struct sk_buff *prev,
1042 struct sk_buff *newsk)
1044 __skb_insert(newsk, prev, prev->next, list);
1047 extern void skb_append(struct sk_buff *old, struct sk_buff *newsk,
1048 struct sk_buff_head *list);
1050 static inline void __skb_queue_before(struct sk_buff_head *list,
1051 struct sk_buff *next,
1052 struct sk_buff *newsk)
1054 __skb_insert(newsk, next->prev, next, list);
1058 * __skb_queue_head - queue a buffer at the list head
1059 * @list: list to use
1060 * @newsk: buffer to queue
1062 * Queue a buffer at the start of a list. This function takes no locks
1063 * and you must therefore hold required locks before calling it.
1065 * A buffer cannot be placed on two lists at the same time.
1067 extern void skb_queue_head(struct sk_buff_head *list, struct sk_buff *newsk);
1068 static inline void __skb_queue_head(struct sk_buff_head *list,
1069 struct sk_buff *newsk)
1071 __skb_queue_after(list, (struct sk_buff *)list, newsk);
1075 * __skb_queue_tail - queue a buffer at the list tail
1076 * @list: list to use
1077 * @newsk: buffer to queue
1079 * Queue a buffer at the end of a list. This function takes no locks
1080 * and you must therefore hold required locks before calling it.
1082 * A buffer cannot be placed on two lists at the same time.
1084 extern void skb_queue_tail(struct sk_buff_head *list, struct sk_buff *newsk);
1085 static inline void __skb_queue_tail(struct sk_buff_head *list,
1086 struct sk_buff *newsk)
1088 __skb_queue_before(list, (struct sk_buff *)list, newsk);
1092 * remove sk_buff from list. _Must_ be called atomically, and with
1095 extern void skb_unlink(struct sk_buff *skb, struct sk_buff_head *list);
1096 static inline void __skb_unlink(struct sk_buff *skb, struct sk_buff_head *list)
1098 struct sk_buff *next, *prev;
1103 skb->next = skb->prev = NULL;
1109 * __skb_dequeue - remove from the head of the queue
1110 * @list: list to dequeue from
1112 * Remove the head of the list. This function does not take any locks
1113 * so must be used with appropriate locks held only. The head item is
1114 * returned or %NULL if the list is empty.
1116 extern struct sk_buff *skb_dequeue(struct sk_buff_head *list);
1117 static inline struct sk_buff *__skb_dequeue(struct sk_buff_head *list)
1119 struct sk_buff *skb = skb_peek(list);
1121 __skb_unlink(skb, list);
1126 * __skb_dequeue_tail - remove from the tail of the queue
1127 * @list: list to dequeue from
1129 * Remove the tail of the list. This function does not take any locks
1130 * so must be used with appropriate locks held only. The tail item is
1131 * returned or %NULL if the list is empty.
1133 extern struct sk_buff *skb_dequeue_tail(struct sk_buff_head *list);
1134 static inline struct sk_buff *__skb_dequeue_tail(struct sk_buff_head *list)
1136 struct sk_buff *skb = skb_peek_tail(list);
1138 __skb_unlink(skb, list);
1143 static inline int skb_is_nonlinear(const struct sk_buff *skb)
1145 return skb->data_len;
1148 static inline unsigned int skb_headlen(const struct sk_buff *skb)
1150 return skb->len - skb->data_len;
1153 static inline int skb_pagelen(const struct sk_buff *skb)
1157 for (i = (int)skb_shinfo(skb)->nr_frags - 1; i >= 0; i--)
1158 len += skb_frag_size(&skb_shinfo(skb)->frags[i]);
1159 return len + skb_headlen(skb);
1163 * __skb_fill_page_desc - initialise a paged fragment in an skb
1164 * @skb: buffer containing fragment to be initialised
1165 * @i: paged fragment index to initialise
1166 * @page: the page to use for this fragment
1167 * @off: the offset to the data with @page
1168 * @size: the length of the data
1170 * Initialises the @i'th fragment of @skb to point to &size bytes at
1171 * offset @off within @page.
1173 * Does not take any additional reference on the fragment.
1175 static inline void __skb_fill_page_desc(struct sk_buff *skb, int i,
1176 struct page *page, int off, int size)
1178 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
1180 frag->page.p = page;
1181 frag->page_offset = off;
1182 skb_frag_size_set(frag, size);
1186 * skb_fill_page_desc - initialise a paged fragment in an skb
1187 * @skb: buffer containing fragment to be initialised
1188 * @i: paged fragment index to initialise
1189 * @page: the page to use for this fragment
1190 * @off: the offset to the data with @page
1191 * @size: the length of the data
1193 * As per __skb_fill_page_desc() -- initialises the @i'th fragment of
1194 * @skb to point to &size bytes at offset @off within @page. In
1195 * addition updates @skb such that @i is the last fragment.
1197 * Does not take any additional reference on the fragment.
1199 static inline void skb_fill_page_desc(struct sk_buff *skb, int i,
1200 struct page *page, int off, int size)
1202 __skb_fill_page_desc(skb, i, page, off, size);
1203 skb_shinfo(skb)->nr_frags = i + 1;
1206 extern void skb_add_rx_frag(struct sk_buff *skb, int i, struct page *page,
1209 #define SKB_PAGE_ASSERT(skb) BUG_ON(skb_shinfo(skb)->nr_frags)
1210 #define SKB_FRAG_ASSERT(skb) BUG_ON(skb_has_frag_list(skb))
1211 #define SKB_LINEAR_ASSERT(skb) BUG_ON(skb_is_nonlinear(skb))
1213 #ifdef NET_SKBUFF_DATA_USES_OFFSET
1214 static inline unsigned char *skb_tail_pointer(const struct sk_buff *skb)
1216 return skb->head + skb->tail;
1219 static inline void skb_reset_tail_pointer(struct sk_buff *skb)
1221 skb->tail = skb->data - skb->head;
1224 static inline void skb_set_tail_pointer(struct sk_buff *skb, const int offset)
1226 skb_reset_tail_pointer(skb);
1227 skb->tail += offset;
1229 #else /* NET_SKBUFF_DATA_USES_OFFSET */
1230 static inline unsigned char *skb_tail_pointer(const struct sk_buff *skb)
1235 static inline void skb_reset_tail_pointer(struct sk_buff *skb)
1237 skb->tail = skb->data;
1240 static inline void skb_set_tail_pointer(struct sk_buff *skb, const int offset)
1242 skb->tail = skb->data + offset;
1245 #endif /* NET_SKBUFF_DATA_USES_OFFSET */
1248 * Add data to an sk_buff
1250 extern unsigned char *skb_put(struct sk_buff *skb, unsigned int len);
1251 static inline unsigned char *__skb_put(struct sk_buff *skb, unsigned int len)
1253 unsigned char *tmp = skb_tail_pointer(skb);
1254 SKB_LINEAR_ASSERT(skb);
1260 extern unsigned char *skb_push(struct sk_buff *skb, unsigned int len);
1261 static inline unsigned char *__skb_push(struct sk_buff *skb, unsigned int len)
1268 extern unsigned char *skb_pull(struct sk_buff *skb, unsigned int len);
1269 static inline unsigned char *__skb_pull(struct sk_buff *skb, unsigned int len)
1272 BUG_ON(skb->len < skb->data_len);
1273 return skb->data += len;
1276 static inline unsigned char *skb_pull_inline(struct sk_buff *skb, unsigned int len)
1278 return unlikely(len > skb->len) ? NULL : __skb_pull(skb, len);
1281 extern unsigned char *__pskb_pull_tail(struct sk_buff *skb, int delta);
1283 static inline unsigned char *__pskb_pull(struct sk_buff *skb, unsigned int len)
1285 if (len > skb_headlen(skb) &&
1286 !__pskb_pull_tail(skb, len - skb_headlen(skb)))
1289 return skb->data += len;
1292 static inline unsigned char *pskb_pull(struct sk_buff *skb, unsigned int len)
1294 return unlikely(len > skb->len) ? NULL : __pskb_pull(skb, len);
1297 static inline int pskb_may_pull(struct sk_buff *skb, unsigned int len)
1299 if (likely(len <= skb_headlen(skb)))
1301 if (unlikely(len > skb->len))
1303 return __pskb_pull_tail(skb, len - skb_headlen(skb)) != NULL;
1307 * skb_headroom - bytes at buffer head
1308 * @skb: buffer to check
1310 * Return the number of bytes of free space at the head of an &sk_buff.
1312 static inline unsigned int skb_headroom(const struct sk_buff *skb)
1314 return skb->data - skb->head;
1318 * skb_tailroom - bytes at buffer end
1319 * @skb: buffer to check
1321 * Return the number of bytes of free space at the tail of an sk_buff
1323 static inline int skb_tailroom(const struct sk_buff *skb)
1325 return skb_is_nonlinear(skb) ? 0 : skb->end - skb->tail;
1329 * skb_reserve - adjust headroom
1330 * @skb: buffer to alter
1331 * @len: bytes to move
1333 * Increase the headroom of an empty &sk_buff by reducing the tail
1334 * room. This is only allowed for an empty buffer.
1336 static inline void skb_reserve(struct sk_buff *skb, int len)
1342 static inline void skb_reset_mac_len(struct sk_buff *skb)
1344 skb->mac_len = skb->network_header - skb->mac_header;
1347 #ifdef NET_SKBUFF_DATA_USES_OFFSET
1348 static inline unsigned char *skb_transport_header(const struct sk_buff *skb)
1350 return skb->head + skb->transport_header;
1353 static inline void skb_reset_transport_header(struct sk_buff *skb)
1355 skb->transport_header = skb->data - skb->head;
1358 static inline void skb_set_transport_header(struct sk_buff *skb,
1361 skb_reset_transport_header(skb);
1362 skb->transport_header += offset;
1365 static inline unsigned char *skb_network_header(const struct sk_buff *skb)
1367 return skb->head + skb->network_header;
1370 static inline void skb_reset_network_header(struct sk_buff *skb)
1372 skb->network_header = skb->data - skb->head;
1375 static inline void skb_set_network_header(struct sk_buff *skb, const int offset)
1377 skb_reset_network_header(skb);
1378 skb->network_header += offset;
1381 static inline unsigned char *skb_mac_header(const struct sk_buff *skb)
1383 return skb->head + skb->mac_header;
1386 static inline int skb_mac_header_was_set(const struct sk_buff *skb)
1388 return skb->mac_header != ~0U;
1391 static inline void skb_reset_mac_header(struct sk_buff *skb)
1393 skb->mac_header = skb->data - skb->head;
1396 static inline void skb_set_mac_header(struct sk_buff *skb, const int offset)
1398 skb_reset_mac_header(skb);
1399 skb->mac_header += offset;
1402 #else /* NET_SKBUFF_DATA_USES_OFFSET */
1404 static inline unsigned char *skb_transport_header(const struct sk_buff *skb)
1406 return skb->transport_header;
1409 static inline void skb_reset_transport_header(struct sk_buff *skb)
1411 skb->transport_header = skb->data;
1414 static inline void skb_set_transport_header(struct sk_buff *skb,
1417 skb->transport_header = skb->data + offset;
1420 static inline unsigned char *skb_network_header(const struct sk_buff *skb)
1422 return skb->network_header;
1425 static inline void skb_reset_network_header(struct sk_buff *skb)
1427 skb->network_header = skb->data;
1430 static inline void skb_set_network_header(struct sk_buff *skb, const int offset)
1432 skb->network_header = skb->data + offset;
1435 static inline unsigned char *skb_mac_header(const struct sk_buff *skb)
1437 return skb->mac_header;
1440 static inline int skb_mac_header_was_set(const struct sk_buff *skb)
1442 return skb->mac_header != NULL;
1445 static inline void skb_reset_mac_header(struct sk_buff *skb)
1447 skb->mac_header = skb->data;
1450 static inline void skb_set_mac_header(struct sk_buff *skb, const int offset)
1452 skb->mac_header = skb->data + offset;
1454 #endif /* NET_SKBUFF_DATA_USES_OFFSET */
1456 static inline void skb_mac_header_rebuild(struct sk_buff *skb)
1458 if (skb_mac_header_was_set(skb)) {
1459 const unsigned char *old_mac = skb_mac_header(skb);
1461 skb_set_mac_header(skb, -skb->mac_len);
1462 memmove(skb_mac_header(skb), old_mac, skb->mac_len);
1466 static inline int skb_checksum_start_offset(const struct sk_buff *skb)
1468 return skb->csum_start - skb_headroom(skb);
1471 static inline int skb_transport_offset(const struct sk_buff *skb)
1473 return skb_transport_header(skb) - skb->data;
1476 static inline u32 skb_network_header_len(const struct sk_buff *skb)
1478 return skb->transport_header - skb->network_header;
1481 static inline int skb_network_offset(const struct sk_buff *skb)
1483 return skb_network_header(skb) - skb->data;
1486 static inline int pskb_network_may_pull(struct sk_buff *skb, unsigned int len)
1488 return pskb_may_pull(skb, skb_network_offset(skb) + len);
1492 * CPUs often take a performance hit when accessing unaligned memory
1493 * locations. The actual performance hit varies, it can be small if the
1494 * hardware handles it or large if we have to take an exception and fix it
1497 * Since an ethernet header is 14 bytes network drivers often end up with
1498 * the IP header at an unaligned offset. The IP header can be aligned by
1499 * shifting the start of the packet by 2 bytes. Drivers should do this
1502 * skb_reserve(skb, NET_IP_ALIGN);
1504 * The downside to this alignment of the IP header is that the DMA is now
1505 * unaligned. On some architectures the cost of an unaligned DMA is high
1506 * and this cost outweighs the gains made by aligning the IP header.
1508 * Since this trade off varies between architectures, we allow NET_IP_ALIGN
1511 #ifndef NET_IP_ALIGN
1512 #define NET_IP_ALIGN 2
1516 * The networking layer reserves some headroom in skb data (via
1517 * dev_alloc_skb). This is used to avoid having to reallocate skb data when
1518 * the header has to grow. In the default case, if the header has to grow
1519 * 32 bytes or less we avoid the reallocation.
1521 * Unfortunately this headroom changes the DMA alignment of the resulting
1522 * network packet. As for NET_IP_ALIGN, this unaligned DMA is expensive
1523 * on some architectures. An architecture can override this value,
1524 * perhaps setting it to a cacheline in size (since that will maintain
1525 * cacheline alignment of the DMA). It must be a power of 2.
1527 * Various parts of the networking layer expect at least 32 bytes of
1528 * headroom, you should not reduce this.
1530 * Using max(32, L1_CACHE_BYTES) makes sense (especially with RPS)
1531 * to reduce average number of cache lines per packet.
1532 * get_rps_cpus() for example only access one 64 bytes aligned block :
1533 * NET_IP_ALIGN(2) + ethernet_header(14) + IP_header(20/40) + ports(8)
1536 #define NET_SKB_PAD max(32, L1_CACHE_BYTES)
1539 extern int ___pskb_trim(struct sk_buff *skb, unsigned int len);
1541 static inline void __skb_trim(struct sk_buff *skb, unsigned int len)
1543 if (unlikely(skb_is_nonlinear(skb))) {
1548 skb_set_tail_pointer(skb, len);
1551 extern void skb_trim(struct sk_buff *skb, unsigned int len);
1553 static inline int __pskb_trim(struct sk_buff *skb, unsigned int len)
1556 return ___pskb_trim(skb, len);
1557 __skb_trim(skb, len);
1561 static inline int pskb_trim(struct sk_buff *skb, unsigned int len)
1563 return (len < skb->len) ? __pskb_trim(skb, len) : 0;
1567 * pskb_trim_unique - remove end from a paged unique (not cloned) buffer
1568 * @skb: buffer to alter
1571 * This is identical to pskb_trim except that the caller knows that
1572 * the skb is not cloned so we should never get an error due to out-
1575 static inline void pskb_trim_unique(struct sk_buff *skb, unsigned int len)
1577 int err = pskb_trim(skb, len);
1582 * skb_orphan - orphan a buffer
1583 * @skb: buffer to orphan
1585 * If a buffer currently has an owner then we call the owner's
1586 * destructor function and make the @skb unowned. The buffer continues
1587 * to exist but is no longer charged to its former owner.
1589 static inline void skb_orphan(struct sk_buff *skb)
1591 if (skb->destructor)
1592 skb->destructor(skb);
1593 skb->destructor = NULL;
1598 * __skb_queue_purge - empty a list
1599 * @list: list to empty
1601 * Delete all buffers on an &sk_buff list. Each buffer is removed from
1602 * the list and one reference dropped. This function does not take the
1603 * list lock and the caller must hold the relevant locks to use it.
1605 extern void skb_queue_purge(struct sk_buff_head *list);
1606 static inline void __skb_queue_purge(struct sk_buff_head *list)
1608 struct sk_buff *skb;
1609 while ((skb = __skb_dequeue(list)) != NULL)
1614 * __dev_alloc_skb - allocate an skbuff for receiving
1615 * @length: length to allocate
1616 * @gfp_mask: get_free_pages mask, passed to alloc_skb
1618 * Allocate a new &sk_buff and assign it a usage count of one. The
1619 * buffer has unspecified headroom built in. Users should allocate
1620 * the headroom they think they need without accounting for the
1621 * built in space. The built in space is used for optimisations.
1623 * %NULL is returned if there is no free memory.
1625 static inline struct sk_buff *__dev_alloc_skb(unsigned int length,
1628 struct sk_buff *skb = alloc_skb(length + NET_SKB_PAD, gfp_mask);
1630 skb_reserve(skb, NET_SKB_PAD);
1634 extern struct sk_buff *dev_alloc_skb(unsigned int length);
1636 extern struct sk_buff *__netdev_alloc_skb(struct net_device *dev,
1637 unsigned int length, gfp_t gfp_mask);
1640 * netdev_alloc_skb - allocate an skbuff for rx on a specific device
1641 * @dev: network device to receive on
1642 * @length: length to allocate
1644 * Allocate a new &sk_buff and assign it a usage count of one. The
1645 * buffer has unspecified headroom built in. Users should allocate
1646 * the headroom they think they need without accounting for the
1647 * built in space. The built in space is used for optimisations.
1649 * %NULL is returned if there is no free memory. Although this function
1650 * allocates memory it can be called from an interrupt.
1652 static inline struct sk_buff *netdev_alloc_skb(struct net_device *dev,
1653 unsigned int length)
1655 return __netdev_alloc_skb(dev, length, GFP_ATOMIC);
1658 static inline struct sk_buff *__netdev_alloc_skb_ip_align(struct net_device *dev,
1659 unsigned int length, gfp_t gfp)
1661 struct sk_buff *skb = __netdev_alloc_skb(dev, length + NET_IP_ALIGN, gfp);
1663 if (NET_IP_ALIGN && skb)
1664 skb_reserve(skb, NET_IP_ALIGN);
1668 static inline struct sk_buff *netdev_alloc_skb_ip_align(struct net_device *dev,
1669 unsigned int length)
1671 return __netdev_alloc_skb_ip_align(dev, length, GFP_ATOMIC);
1675 * __netdev_alloc_page - allocate a page for ps-rx on a specific device
1676 * @dev: network device to receive on
1677 * @gfp_mask: alloc_pages_node mask
1679 * Allocate a new page. dev currently unused.
1681 * %NULL is returned if there is no free memory.
1683 static inline struct page *__netdev_alloc_page(struct net_device *dev, gfp_t gfp_mask)
1685 return alloc_pages_node(NUMA_NO_NODE, gfp_mask, 0);
1689 * netdev_alloc_page - allocate a page for ps-rx on a specific device
1690 * @dev: network device to receive on
1692 * Allocate a new page. dev currently unused.
1694 * %NULL is returned if there is no free memory.
1696 static inline struct page *netdev_alloc_page(struct net_device *dev)
1698 return __netdev_alloc_page(dev, GFP_ATOMIC);
1701 static inline void netdev_free_page(struct net_device *dev, struct page *page)
1707 * skb_frag_page - retrieve the page refered to by a paged fragment
1708 * @frag: the paged fragment
1710 * Returns the &struct page associated with @frag.
1712 static inline struct page *skb_frag_page(const skb_frag_t *frag)
1714 return frag->page.p;
1718 * __skb_frag_ref - take an addition reference on a paged fragment.
1719 * @frag: the paged fragment
1721 * Takes an additional reference on the paged fragment @frag.
1723 static inline void __skb_frag_ref(skb_frag_t *frag)
1725 get_page(skb_frag_page(frag));
1729 * skb_frag_ref - take an addition reference on a paged fragment of an skb.
1731 * @f: the fragment offset.
1733 * Takes an additional reference on the @f'th paged fragment of @skb.
1735 static inline void skb_frag_ref(struct sk_buff *skb, int f)
1737 __skb_frag_ref(&skb_shinfo(skb)->frags[f]);
1741 * __skb_frag_unref - release a reference on a paged fragment.
1742 * @frag: the paged fragment
1744 * Releases a reference on the paged fragment @frag.
1746 static inline void __skb_frag_unref(skb_frag_t *frag)
1748 put_page(skb_frag_page(frag));
1752 * skb_frag_unref - release a reference on a paged fragment of an skb.
1754 * @f: the fragment offset
1756 * Releases a reference on the @f'th paged fragment of @skb.
1758 static inline void skb_frag_unref(struct sk_buff *skb, int f)
1760 __skb_frag_unref(&skb_shinfo(skb)->frags[f]);
1764 * skb_frag_address - gets the address of the data contained in a paged fragment
1765 * @frag: the paged fragment buffer
1767 * Returns the address of the data within @frag. The page must already
1770 static inline void *skb_frag_address(const skb_frag_t *frag)
1772 return page_address(skb_frag_page(frag)) + frag->page_offset;
1776 * skb_frag_address_safe - gets the address of the data contained in a paged fragment
1777 * @frag: the paged fragment buffer
1779 * Returns the address of the data within @frag. Checks that the page
1780 * is mapped and returns %NULL otherwise.
1782 static inline void *skb_frag_address_safe(const skb_frag_t *frag)
1784 void *ptr = page_address(skb_frag_page(frag));
1788 return ptr + frag->page_offset;
1792 * __skb_frag_set_page - sets the page contained in a paged fragment
1793 * @frag: the paged fragment
1794 * @page: the page to set
1796 * Sets the fragment @frag to contain @page.
1798 static inline void __skb_frag_set_page(skb_frag_t *frag, struct page *page)
1800 frag->page.p = page;
1804 * skb_frag_set_page - sets the page contained in a paged fragment of an skb
1806 * @f: the fragment offset
1807 * @page: the page to set
1809 * Sets the @f'th fragment of @skb to contain @page.
1811 static inline void skb_frag_set_page(struct sk_buff *skb, int f,
1814 __skb_frag_set_page(&skb_shinfo(skb)->frags[f], page);
1818 * skb_frag_dma_map - maps a paged fragment via the DMA API
1819 * @dev: the device to map the fragment to
1820 * @frag: the paged fragment to map
1821 * @offset: the offset within the fragment (starting at the
1822 * fragment's own offset)
1823 * @size: the number of bytes to map
1824 * @dir: the direction of the mapping (%PCI_DMA_*)
1826 * Maps the page associated with @frag to @device.
1828 static inline dma_addr_t skb_frag_dma_map(struct device *dev,
1829 const skb_frag_t *frag,
1830 size_t offset, size_t size,
1831 enum dma_data_direction dir)
1833 return dma_map_page(dev, skb_frag_page(frag),
1834 frag->page_offset + offset, size, dir);
1838 * skb_clone_writable - is the header of a clone writable
1839 * @skb: buffer to check
1840 * @len: length up to which to write
1842 * Returns true if modifying the header part of the cloned buffer
1843 * does not requires the data to be copied.
1845 static inline int skb_clone_writable(const struct sk_buff *skb, unsigned int len)
1847 return !skb_header_cloned(skb) &&
1848 skb_headroom(skb) + len <= skb->hdr_len;
1851 static inline int __skb_cow(struct sk_buff *skb, unsigned int headroom,
1856 if (headroom < NET_SKB_PAD)
1857 headroom = NET_SKB_PAD;
1858 if (headroom > skb_headroom(skb))
1859 delta = headroom - skb_headroom(skb);
1861 if (delta || cloned)
1862 return pskb_expand_head(skb, ALIGN(delta, NET_SKB_PAD), 0,
1868 * skb_cow - copy header of skb when it is required
1869 * @skb: buffer to cow
1870 * @headroom: needed headroom
1872 * If the skb passed lacks sufficient headroom or its data part
1873 * is shared, data is reallocated. If reallocation fails, an error
1874 * is returned and original skb is not changed.
1876 * The result is skb with writable area skb->head...skb->tail
1877 * and at least @headroom of space at head.
1879 static inline int skb_cow(struct sk_buff *skb, unsigned int headroom)
1881 return __skb_cow(skb, headroom, skb_cloned(skb));
1885 * skb_cow_head - skb_cow but only making the head writable
1886 * @skb: buffer to cow
1887 * @headroom: needed headroom
1889 * This function is identical to skb_cow except that we replace the
1890 * skb_cloned check by skb_header_cloned. It should be used when
1891 * you only need to push on some header and do not need to modify
1894 static inline int skb_cow_head(struct sk_buff *skb, unsigned int headroom)
1896 return __skb_cow(skb, headroom, skb_header_cloned(skb));
1900 * skb_padto - pad an skbuff up to a minimal size
1901 * @skb: buffer to pad
1902 * @len: minimal length
1904 * Pads up a buffer to ensure the trailing bytes exist and are
1905 * blanked. If the buffer already contains sufficient data it
1906 * is untouched. Otherwise it is extended. Returns zero on
1907 * success. The skb is freed on error.
1910 static inline int skb_padto(struct sk_buff *skb, unsigned int len)
1912 unsigned int size = skb->len;
1913 if (likely(size >= len))
1915 return skb_pad(skb, len - size);
1918 static inline int skb_add_data(struct sk_buff *skb,
1919 char __user *from, int copy)
1921 const int off = skb->len;
1923 if (skb->ip_summed == CHECKSUM_NONE) {
1925 __wsum csum = csum_and_copy_from_user(from, skb_put(skb, copy),
1928 skb->csum = csum_block_add(skb->csum, csum, off);
1931 } else if (!copy_from_user(skb_put(skb, copy), from, copy))
1934 __skb_trim(skb, off);
1938 static inline int skb_can_coalesce(struct sk_buff *skb, int i,
1939 const struct page *page, int off)
1942 const struct skb_frag_struct *frag = &skb_shinfo(skb)->frags[i - 1];
1944 return page == skb_frag_page(frag) &&
1945 off == frag->page_offset + skb_frag_size(frag);
1950 static inline int __skb_linearize(struct sk_buff *skb)
1952 return __pskb_pull_tail(skb, skb->data_len) ? 0 : -ENOMEM;
1956 * skb_linearize - convert paged skb to linear one
1957 * @skb: buffer to linarize
1959 * If there is no free memory -ENOMEM is returned, otherwise zero
1960 * is returned and the old skb data released.
1962 static inline int skb_linearize(struct sk_buff *skb)
1964 return skb_is_nonlinear(skb) ? __skb_linearize(skb) : 0;
1968 * skb_linearize_cow - make sure skb is linear and writable
1969 * @skb: buffer to process
1971 * If there is no free memory -ENOMEM is returned, otherwise zero
1972 * is returned and the old skb data released.
1974 static inline int skb_linearize_cow(struct sk_buff *skb)
1976 return skb_is_nonlinear(skb) || skb_cloned(skb) ?
1977 __skb_linearize(skb) : 0;
1981 * skb_postpull_rcsum - update checksum for received skb after pull
1982 * @skb: buffer to update
1983 * @start: start of data before pull
1984 * @len: length of data pulled
1986 * After doing a pull on a received packet, you need to call this to
1987 * update the CHECKSUM_COMPLETE checksum, or set ip_summed to
1988 * CHECKSUM_NONE so that it can be recomputed from scratch.
1991 static inline void skb_postpull_rcsum(struct sk_buff *skb,
1992 const void *start, unsigned int len)
1994 if (skb->ip_summed == CHECKSUM_COMPLETE)
1995 skb->csum = csum_sub(skb->csum, csum_partial(start, len, 0));
1998 unsigned char *skb_pull_rcsum(struct sk_buff *skb, unsigned int len);
2001 * pskb_trim_rcsum - trim received skb and update checksum
2002 * @skb: buffer to trim
2005 * This is exactly the same as pskb_trim except that it ensures the
2006 * checksum of received packets are still valid after the operation.
2009 static inline int pskb_trim_rcsum(struct sk_buff *skb, unsigned int len)
2011 if (likely(len >= skb->len))
2013 if (skb->ip_summed == CHECKSUM_COMPLETE)
2014 skb->ip_summed = CHECKSUM_NONE;
2015 return __pskb_trim(skb, len);
2018 #define skb_queue_walk(queue, skb) \
2019 for (skb = (queue)->next; \
2020 skb != (struct sk_buff *)(queue); \
2023 #define skb_queue_walk_safe(queue, skb, tmp) \
2024 for (skb = (queue)->next, tmp = skb->next; \
2025 skb != (struct sk_buff *)(queue); \
2026 skb = tmp, tmp = skb->next)
2028 #define skb_queue_walk_from(queue, skb) \
2029 for (; skb != (struct sk_buff *)(queue); \
2032 #define skb_queue_walk_from_safe(queue, skb, tmp) \
2033 for (tmp = skb->next; \
2034 skb != (struct sk_buff *)(queue); \
2035 skb = tmp, tmp = skb->next)
2037 #define skb_queue_reverse_walk(queue, skb) \
2038 for (skb = (queue)->prev; \
2039 skb != (struct sk_buff *)(queue); \
2042 #define skb_queue_reverse_walk_safe(queue, skb, tmp) \
2043 for (skb = (queue)->prev, tmp = skb->prev; \
2044 skb != (struct sk_buff *)(queue); \
2045 skb = tmp, tmp = skb->prev)
2047 #define skb_queue_reverse_walk_from_safe(queue, skb, tmp) \
2048 for (tmp = skb->prev; \
2049 skb != (struct sk_buff *)(queue); \
2050 skb = tmp, tmp = skb->prev)
2052 static inline bool skb_has_frag_list(const struct sk_buff *skb)
2054 return skb_shinfo(skb)->frag_list != NULL;
2057 static inline void skb_frag_list_init(struct sk_buff *skb)
2059 skb_shinfo(skb)->frag_list = NULL;
2062 static inline void skb_frag_add_head(struct sk_buff *skb, struct sk_buff *frag)
2064 frag->next = skb_shinfo(skb)->frag_list;
2065 skb_shinfo(skb)->frag_list = frag;
2068 #define skb_walk_frags(skb, iter) \
2069 for (iter = skb_shinfo(skb)->frag_list; iter; iter = iter->next)
2071 extern struct sk_buff *__skb_recv_datagram(struct sock *sk, unsigned flags,
2072 int *peeked, int *err);
2073 extern struct sk_buff *skb_recv_datagram(struct sock *sk, unsigned flags,
2074 int noblock, int *err);
2075 extern unsigned int datagram_poll(struct file *file, struct socket *sock,
2076 struct poll_table_struct *wait);
2077 extern int skb_copy_datagram_iovec(const struct sk_buff *from,
2078 int offset, struct iovec *to,
2080 extern int skb_copy_and_csum_datagram_iovec(struct sk_buff *skb,
2083 extern int skb_copy_datagram_from_iovec(struct sk_buff *skb,
2085 const struct iovec *from,
2088 extern int skb_copy_datagram_const_iovec(const struct sk_buff *from,
2090 const struct iovec *to,
2093 extern void skb_free_datagram(struct sock *sk, struct sk_buff *skb);
2094 extern void skb_free_datagram_locked(struct sock *sk,
2095 struct sk_buff *skb);
2096 extern int skb_kill_datagram(struct sock *sk, struct sk_buff *skb,
2097 unsigned int flags);
2098 extern __wsum skb_checksum(const struct sk_buff *skb, int offset,
2099 int len, __wsum csum);
2100 extern int skb_copy_bits(const struct sk_buff *skb, int offset,
2102 extern int skb_store_bits(struct sk_buff *skb, int offset,
2103 const void *from, int len);
2104 extern __wsum skb_copy_and_csum_bits(const struct sk_buff *skb,
2105 int offset, u8 *to, int len,
2107 extern int skb_splice_bits(struct sk_buff *skb,
2108 unsigned int offset,
2109 struct pipe_inode_info *pipe,
2111 unsigned int flags);
2112 extern void skb_copy_and_csum_dev(const struct sk_buff *skb, u8 *to);
2113 extern void skb_split(struct sk_buff *skb,
2114 struct sk_buff *skb1, const u32 len);
2115 extern int skb_shift(struct sk_buff *tgt, struct sk_buff *skb,
2118 extern struct sk_buff *skb_segment(struct sk_buff *skb, u32 features);
2120 static inline void *skb_header_pointer(const struct sk_buff *skb, int offset,
2121 int len, void *buffer)
2123 int hlen = skb_headlen(skb);
2125 if (hlen - offset >= len)
2126 return skb->data + offset;
2128 if (skb_copy_bits(skb, offset, buffer, len) < 0)
2134 static inline void skb_copy_from_linear_data(const struct sk_buff *skb,
2136 const unsigned int len)
2138 memcpy(to, skb->data, len);
2141 static inline void skb_copy_from_linear_data_offset(const struct sk_buff *skb,
2142 const int offset, void *to,
2143 const unsigned int len)
2145 memcpy(to, skb->data + offset, len);
2148 static inline void skb_copy_to_linear_data(struct sk_buff *skb,
2150 const unsigned int len)
2152 memcpy(skb->data, from, len);
2155 static inline void skb_copy_to_linear_data_offset(struct sk_buff *skb,
2158 const unsigned int len)
2160 memcpy(skb->data + offset, from, len);
2163 extern void skb_init(void);
2165 static inline ktime_t skb_get_ktime(const struct sk_buff *skb)
2171 * skb_get_timestamp - get timestamp from a skb
2172 * @skb: skb to get stamp from
2173 * @stamp: pointer to struct timeval to store stamp in
2175 * Timestamps are stored in the skb as offsets to a base timestamp.
2176 * This function converts the offset back to a struct timeval and stores
2179 static inline void skb_get_timestamp(const struct sk_buff *skb,
2180 struct timeval *stamp)
2182 *stamp = ktime_to_timeval(skb->tstamp);
2185 static inline void skb_get_timestampns(const struct sk_buff *skb,
2186 struct timespec *stamp)
2188 *stamp = ktime_to_timespec(skb->tstamp);
2191 static inline void __net_timestamp(struct sk_buff *skb)
2193 skb->tstamp = ktime_get_real();
2196 static inline ktime_t net_timedelta(ktime_t t)
2198 return ktime_sub(ktime_get_real(), t);
2201 static inline ktime_t net_invalid_timestamp(void)
2203 return ktime_set(0, 0);
2206 extern void skb_timestamping_init(void);
2208 #ifdef CONFIG_NETWORK_PHY_TIMESTAMPING
2210 extern void skb_clone_tx_timestamp(struct sk_buff *skb);
2211 extern bool skb_defer_rx_timestamp(struct sk_buff *skb);
2213 #else /* CONFIG_NETWORK_PHY_TIMESTAMPING */
2215 static inline void skb_clone_tx_timestamp(struct sk_buff *skb)
2219 static inline bool skb_defer_rx_timestamp(struct sk_buff *skb)
2224 #endif /* !CONFIG_NETWORK_PHY_TIMESTAMPING */
2227 * skb_complete_tx_timestamp() - deliver cloned skb with tx timestamps
2229 * PHY drivers may accept clones of transmitted packets for
2230 * timestamping via their phy_driver.txtstamp method. These drivers
2231 * must call this function to return the skb back to the stack, with
2232 * or without a timestamp.
2234 * @skb: clone of the the original outgoing packet
2235 * @hwtstamps: hardware time stamps, may be NULL if not available
2238 void skb_complete_tx_timestamp(struct sk_buff *skb,
2239 struct skb_shared_hwtstamps *hwtstamps);
2242 * skb_tstamp_tx - queue clone of skb with send time stamps
2243 * @orig_skb: the original outgoing packet
2244 * @hwtstamps: hardware time stamps, may be NULL if not available
2246 * If the skb has a socket associated, then this function clones the
2247 * skb (thus sharing the actual data and optional structures), stores
2248 * the optional hardware time stamping information (if non NULL) or
2249 * generates a software time stamp (otherwise), then queues the clone
2250 * to the error queue of the socket. Errors are silently ignored.
2252 extern void skb_tstamp_tx(struct sk_buff *orig_skb,
2253 struct skb_shared_hwtstamps *hwtstamps);
2255 static inline void sw_tx_timestamp(struct sk_buff *skb)
2257 if (skb_shinfo(skb)->tx_flags & SKBTX_SW_TSTAMP &&
2258 !(skb_shinfo(skb)->tx_flags & SKBTX_IN_PROGRESS))
2259 skb_tstamp_tx(skb, NULL);
2263 * skb_tx_timestamp() - Driver hook for transmit timestamping
2265 * Ethernet MAC Drivers should call this function in their hard_xmit()
2266 * function immediately before giving the sk_buff to the MAC hardware.
2268 * @skb: A socket buffer.
2270 static inline void skb_tx_timestamp(struct sk_buff *skb)
2272 skb_clone_tx_timestamp(skb);
2273 sw_tx_timestamp(skb);
2276 extern __sum16 __skb_checksum_complete_head(struct sk_buff *skb, int len);
2277 extern __sum16 __skb_checksum_complete(struct sk_buff *skb);
2279 static inline int skb_csum_unnecessary(const struct sk_buff *skb)
2281 return skb->ip_summed & CHECKSUM_UNNECESSARY;
2285 * skb_checksum_complete - Calculate checksum of an entire packet
2286 * @skb: packet to process
2288 * This function calculates the checksum over the entire packet plus
2289 * the value of skb->csum. The latter can be used to supply the
2290 * checksum of a pseudo header as used by TCP/UDP. It returns the
2293 * For protocols that contain complete checksums such as ICMP/TCP/UDP,
2294 * this function can be used to verify that checksum on received
2295 * packets. In that case the function should return zero if the
2296 * checksum is correct. In particular, this function will return zero
2297 * if skb->ip_summed is CHECKSUM_UNNECESSARY which indicates that the
2298 * hardware has already verified the correctness of the checksum.
2300 static inline __sum16 skb_checksum_complete(struct sk_buff *skb)
2302 return skb_csum_unnecessary(skb) ?
2303 0 : __skb_checksum_complete(skb);
2306 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
2307 extern void nf_conntrack_destroy(struct nf_conntrack *nfct);
2308 static inline void nf_conntrack_put(struct nf_conntrack *nfct)
2310 if (nfct && atomic_dec_and_test(&nfct->use))
2311 nf_conntrack_destroy(nfct);
2313 static inline void nf_conntrack_get(struct nf_conntrack *nfct)
2316 atomic_inc(&nfct->use);
2319 #ifdef NET_SKBUFF_NF_DEFRAG_NEEDED
2320 static inline void nf_conntrack_get_reasm(struct sk_buff *skb)
2323 atomic_inc(&skb->users);
2325 static inline void nf_conntrack_put_reasm(struct sk_buff *skb)
2331 #ifdef CONFIG_BRIDGE_NETFILTER
2332 static inline void nf_bridge_put(struct nf_bridge_info *nf_bridge)
2334 if (nf_bridge && atomic_dec_and_test(&nf_bridge->use))
2337 static inline void nf_bridge_get(struct nf_bridge_info *nf_bridge)
2340 atomic_inc(&nf_bridge->use);
2342 #endif /* CONFIG_BRIDGE_NETFILTER */
2343 static inline void nf_reset(struct sk_buff *skb)
2345 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
2346 nf_conntrack_put(skb->nfct);
2349 #ifdef NET_SKBUFF_NF_DEFRAG_NEEDED
2350 nf_conntrack_put_reasm(skb->nfct_reasm);
2351 skb->nfct_reasm = NULL;
2353 #ifdef CONFIG_BRIDGE_NETFILTER
2354 nf_bridge_put(skb->nf_bridge);
2355 skb->nf_bridge = NULL;
2359 /* Note: This doesn't put any conntrack and bridge info in dst. */
2360 static inline void __nf_copy(struct sk_buff *dst, const struct sk_buff *src)
2362 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
2363 dst->nfct = src->nfct;
2364 nf_conntrack_get(src->nfct);
2365 dst->nfctinfo = src->nfctinfo;
2367 #ifdef NET_SKBUFF_NF_DEFRAG_NEEDED
2368 dst->nfct_reasm = src->nfct_reasm;
2369 nf_conntrack_get_reasm(src->nfct_reasm);
2371 #ifdef CONFIG_BRIDGE_NETFILTER
2372 dst->nf_bridge = src->nf_bridge;
2373 nf_bridge_get(src->nf_bridge);
2377 static inline void nf_copy(struct sk_buff *dst, const struct sk_buff *src)
2379 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
2380 nf_conntrack_put(dst->nfct);
2382 #ifdef NET_SKBUFF_NF_DEFRAG_NEEDED
2383 nf_conntrack_put_reasm(dst->nfct_reasm);
2385 #ifdef CONFIG_BRIDGE_NETFILTER
2386 nf_bridge_put(dst->nf_bridge);
2388 __nf_copy(dst, src);
2391 #ifdef CONFIG_NETWORK_SECMARK
2392 static inline void skb_copy_secmark(struct sk_buff *to, const struct sk_buff *from)
2394 to->secmark = from->secmark;
2397 static inline void skb_init_secmark(struct sk_buff *skb)
2402 static inline void skb_copy_secmark(struct sk_buff *to, const struct sk_buff *from)
2405 static inline void skb_init_secmark(struct sk_buff *skb)
2409 static inline void skb_set_queue_mapping(struct sk_buff *skb, u16 queue_mapping)
2411 skb->queue_mapping = queue_mapping;
2414 static inline u16 skb_get_queue_mapping(const struct sk_buff *skb)
2416 return skb->queue_mapping;
2419 static inline void skb_copy_queue_mapping(struct sk_buff *to, const struct sk_buff *from)
2421 to->queue_mapping = from->queue_mapping;
2424 static inline void skb_record_rx_queue(struct sk_buff *skb, u16 rx_queue)
2426 skb->queue_mapping = rx_queue + 1;
2429 static inline u16 skb_get_rx_queue(const struct sk_buff *skb)
2431 return skb->queue_mapping - 1;
2434 static inline bool skb_rx_queue_recorded(const struct sk_buff *skb)
2436 return skb->queue_mapping != 0;
2439 extern u16 __skb_tx_hash(const struct net_device *dev,
2440 const struct sk_buff *skb,
2441 unsigned int num_tx_queues);
2444 static inline struct sec_path *skb_sec_path(struct sk_buff *skb)
2449 static inline struct sec_path *skb_sec_path(struct sk_buff *skb)
2455 static inline int skb_is_gso(const struct sk_buff *skb)
2457 return skb_shinfo(skb)->gso_size;
2460 static inline int skb_is_gso_v6(const struct sk_buff *skb)
2462 return skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6;
2465 extern void __skb_warn_lro_forwarding(const struct sk_buff *skb);
2467 static inline bool skb_warn_if_lro(const struct sk_buff *skb)
2469 /* LRO sets gso_size but not gso_type, whereas if GSO is really
2470 * wanted then gso_type will be set. */
2471 const struct skb_shared_info *shinfo = skb_shinfo(skb);
2473 if (skb_is_nonlinear(skb) && shinfo->gso_size != 0 &&
2474 unlikely(shinfo->gso_type == 0)) {
2475 __skb_warn_lro_forwarding(skb);
2481 static inline void skb_forward_csum(struct sk_buff *skb)
2483 /* Unfortunately we don't support this one. Any brave souls? */
2484 if (skb->ip_summed == CHECKSUM_COMPLETE)
2485 skb->ip_summed = CHECKSUM_NONE;
2489 * skb_checksum_none_assert - make sure skb ip_summed is CHECKSUM_NONE
2490 * @skb: skb to check
2492 * fresh skbs have their ip_summed set to CHECKSUM_NONE.
2493 * Instead of forcing ip_summed to CHECKSUM_NONE, we can
2494 * use this helper, to document places where we make this assertion.
2496 static inline void skb_checksum_none_assert(const struct sk_buff *skb)
2499 BUG_ON(skb->ip_summed != CHECKSUM_NONE);
2503 bool skb_partial_csum_set(struct sk_buff *skb, u16 start, u16 off);
2505 static inline bool skb_is_recycleable(const struct sk_buff *skb, int skb_size)
2507 if (irqs_disabled())
2510 if (skb_shinfo(skb)->tx_flags & SKBTX_DEV_ZEROCOPY)
2513 if (skb_is_nonlinear(skb) || skb->fclone != SKB_FCLONE_UNAVAILABLE)
2516 skb_size = SKB_DATA_ALIGN(skb_size + NET_SKB_PAD);
2517 if (skb_end_pointer(skb) - skb->head < skb_size)
2520 if (skb_shared(skb) || skb_cloned(skb))
2525 #endif /* __KERNEL__ */
2526 #endif /* _LINUX_SKBUFF_H */