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>
33 #include <linux/netdev_features.h>
35 /* Don't change this without changing skb_csum_unnecessary! */
36 #define CHECKSUM_NONE 0
37 #define CHECKSUM_UNNECESSARY 1
38 #define CHECKSUM_COMPLETE 2
39 #define CHECKSUM_PARTIAL 3
41 #define SKB_DATA_ALIGN(X) (((X) + (SMP_CACHE_BYTES - 1)) & \
42 ~(SMP_CACHE_BYTES - 1))
43 #define SKB_WITH_OVERHEAD(X) \
44 ((X) - SKB_DATA_ALIGN(sizeof(struct skb_shared_info)))
45 #define SKB_MAX_ORDER(X, ORDER) \
46 SKB_WITH_OVERHEAD((PAGE_SIZE << (ORDER)) - (X))
47 #define SKB_MAX_HEAD(X) (SKB_MAX_ORDER((X), 0))
48 #define SKB_MAX_ALLOC (SKB_MAX_ORDER(0, 2))
50 /* return minimum truesize of one skb containing X bytes of data */
51 #define SKB_TRUESIZE(X) ((X) + \
52 SKB_DATA_ALIGN(sizeof(struct sk_buff)) + \
53 SKB_DATA_ALIGN(sizeof(struct skb_shared_info)))
55 /* A. Checksumming of received packets by device.
57 * NONE: device failed to checksum this packet.
58 * skb->csum is undefined.
60 * UNNECESSARY: device parsed packet and wouldbe verified checksum.
61 * skb->csum is undefined.
62 * It is bad option, but, unfortunately, many of vendors do this.
63 * Apparently with secret goal to sell you new device, when you
64 * will add new protocol to your host. F.e. IPv6. 8)
66 * COMPLETE: the most generic way. Device supplied checksum of _all_
67 * the packet as seen by netif_rx in skb->csum.
68 * NOTE: Even if device supports only some protocols, but
69 * is able to produce some skb->csum, it MUST use COMPLETE,
72 * PARTIAL: identical to the case for output below. This may occur
73 * on a packet received directly from another Linux OS, e.g.,
74 * a virtualised Linux kernel on the same host. The packet can
75 * be treated in the same way as UNNECESSARY except that on
76 * output (i.e., forwarding) the checksum must be filled in
77 * by the OS or the hardware.
79 * B. Checksumming on output.
81 * NONE: skb is checksummed by protocol or csum is not required.
83 * PARTIAL: device is required to csum packet as seen by hard_start_xmit
84 * from skb->csum_start to the end and to record the checksum
85 * at skb->csum_start + skb->csum_offset.
87 * Device must show its capabilities in dev->features, set
88 * at device setup time.
89 * NETIF_F_HW_CSUM - it is clever device, it is able to checksum
91 * NETIF_F_NO_CSUM - loopback or reliable single hop media.
92 * NETIF_F_IP_CSUM - device is dumb. It is able to csum only
93 * TCP/UDP over IPv4. Sigh. Vendors like this
94 * way by an unknown reason. Though, see comment above
95 * about CHECKSUM_UNNECESSARY. 8)
96 * NETIF_F_IPV6_CSUM about as dumb as the last one but does IPv6 instead.
98 * Any questions? No questions, good. --ANK
103 struct pipe_inode_info;
105 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
106 struct nf_conntrack {
111 #ifdef CONFIG_BRIDGE_NETFILTER
112 struct nf_bridge_info {
114 struct net_device *physindev;
115 struct net_device *physoutdev;
117 unsigned long data[32 / sizeof(unsigned long)];
121 struct sk_buff_head {
122 /* These two members must be first. */
123 struct sk_buff *next;
124 struct sk_buff *prev;
132 /* To allow 64K frame to be packed as single skb without frag_list. Since
133 * GRO uses frags we allocate at least 16 regardless of page size.
135 #if (65536/PAGE_SIZE + 2) < 16
136 #define MAX_SKB_FRAGS 16UL
138 #define MAX_SKB_FRAGS (65536/PAGE_SIZE + 2)
141 typedef struct skb_frag_struct skb_frag_t;
143 struct skb_frag_struct {
147 #if (BITS_PER_LONG > 32) || (PAGE_SIZE >= 65536)
156 static inline unsigned int skb_frag_size(const skb_frag_t *frag)
161 static inline void skb_frag_size_set(skb_frag_t *frag, unsigned int size)
166 static inline void skb_frag_size_add(skb_frag_t *frag, int delta)
171 static inline void skb_frag_size_sub(skb_frag_t *frag, int delta)
176 #define HAVE_HW_TIME_STAMP
179 * struct skb_shared_hwtstamps - hardware time stamps
180 * @hwtstamp: hardware time stamp transformed into duration
181 * since arbitrary point in time
182 * @syststamp: hwtstamp transformed to system time base
184 * Software time stamps generated by ktime_get_real() are stored in
185 * skb->tstamp. The relation between the different kinds of time
186 * stamps is as follows:
188 * syststamp and tstamp can be compared against each other in
189 * arbitrary combinations. The accuracy of a
190 * syststamp/tstamp/"syststamp from other device" comparison is
191 * limited by the accuracy of the transformation into system time
192 * base. This depends on the device driver and its underlying
195 * hwtstamps can only be compared against other hwtstamps from
198 * This structure is attached to packets as part of the
199 * &skb_shared_info. Use skb_hwtstamps() to get a pointer.
201 struct skb_shared_hwtstamps {
206 /* Definitions for tx_flags in struct skb_shared_info */
208 /* generate hardware time stamp */
209 SKBTX_HW_TSTAMP = 1 << 0,
211 /* generate software time stamp */
212 SKBTX_SW_TSTAMP = 1 << 1,
214 /* device driver is going to provide hardware time stamp */
215 SKBTX_IN_PROGRESS = 1 << 2,
217 /* ensure the originating sk reference is available on driver level */
218 SKBTX_DRV_NEEDS_SK_REF = 1 << 3,
220 /* device driver supports TX zero-copy buffers */
221 SKBTX_DEV_ZEROCOPY = 1 << 4,
225 * The callback notifies userspace to release buffers when skb DMA is done in
226 * lower device, the skb last reference should be 0 when calling this.
227 * The desc is used to track userspace buffer index.
230 void (*callback)(void *);
235 /* This data is invariant across clones and lives at
236 * the end of the header data, ie. at skb->end.
238 struct skb_shared_info {
239 unsigned short nr_frags;
240 unsigned short gso_size;
241 /* Warning: this field is not always filled in (UFO)! */
242 unsigned short gso_segs;
243 unsigned short gso_type;
246 struct sk_buff *frag_list;
247 struct skb_shared_hwtstamps hwtstamps;
250 * Warning : all fields before dataref are cleared in __alloc_skb()
254 /* Intermediate layers must ensure that destructor_arg
255 * remains valid until skb destructor */
256 void * destructor_arg;
258 /* must be last field, see pskb_expand_head() */
259 skb_frag_t frags[MAX_SKB_FRAGS];
262 /* We divide dataref into two halves. The higher 16 bits hold references
263 * to the payload part of skb->data. The lower 16 bits hold references to
264 * the entire skb->data. A clone of a headerless skb holds the length of
265 * the header in skb->hdr_len.
267 * All users must obey the rule that the skb->data reference count must be
268 * greater than or equal to the payload reference count.
270 * Holding a reference to the payload part means that the user does not
271 * care about modifications to the header part of skb->data.
273 #define SKB_DATAREF_SHIFT 16
274 #define SKB_DATAREF_MASK ((1 << SKB_DATAREF_SHIFT) - 1)
278 SKB_FCLONE_UNAVAILABLE,
284 SKB_GSO_TCPV4 = 1 << 0,
285 SKB_GSO_UDP = 1 << 1,
287 /* This indicates the skb is from an untrusted source. */
288 SKB_GSO_DODGY = 1 << 2,
290 /* This indicates the tcp segment has CWR set. */
291 SKB_GSO_TCP_ECN = 1 << 3,
293 SKB_GSO_TCPV6 = 1 << 4,
295 SKB_GSO_FCOE = 1 << 5,
298 #if BITS_PER_LONG > 32
299 #define NET_SKBUFF_DATA_USES_OFFSET 1
302 #ifdef NET_SKBUFF_DATA_USES_OFFSET
303 typedef unsigned int sk_buff_data_t;
305 typedef unsigned char *sk_buff_data_t;
308 #if defined(CONFIG_NF_DEFRAG_IPV4) || defined(CONFIG_NF_DEFRAG_IPV4_MODULE) || \
309 defined(CONFIG_NF_DEFRAG_IPV6) || defined(CONFIG_NF_DEFRAG_IPV6_MODULE)
310 #define NET_SKBUFF_NF_DEFRAG_NEEDED 1
314 * struct sk_buff - socket buffer
315 * @next: Next buffer in list
316 * @prev: Previous buffer in list
317 * @tstamp: Time we arrived
318 * @sk: Socket we are owned by
319 * @dev: Device we arrived on/are leaving by
320 * @cb: Control buffer. Free for use by every layer. Put private vars here
321 * @_skb_refdst: destination entry (with norefcount bit)
322 * @sp: the security path, used for xfrm
323 * @len: Length of actual data
324 * @data_len: Data length
325 * @mac_len: Length of link layer header
326 * @hdr_len: writable header length of cloned skb
327 * @csum: Checksum (must include start/offset pair)
328 * @csum_start: Offset from skb->head where checksumming should start
329 * @csum_offset: Offset from csum_start where checksum should be stored
330 * @priority: Packet queueing priority
331 * @local_df: allow local fragmentation
332 * @cloned: Head may be cloned (check refcnt to be sure)
333 * @ip_summed: Driver fed us an IP checksum
334 * @nohdr: Payload reference only, must not modify header
335 * @nfctinfo: Relationship of this skb to the connection
336 * @pkt_type: Packet class
337 * @fclone: skbuff clone status
338 * @ipvs_property: skbuff is owned by ipvs
339 * @peeked: this packet has been seen already, so stats have been
340 * done for it, don't do them again
341 * @nf_trace: netfilter packet trace flag
342 * @protocol: Packet protocol from driver
343 * @destructor: Destruct function
344 * @nfct: Associated connection, if any
345 * @nfct_reasm: netfilter conntrack re-assembly pointer
346 * @nf_bridge: Saved data about a bridged frame - see br_netfilter.c
347 * @skb_iif: ifindex of device we arrived on
348 * @tc_index: Traffic control index
349 * @tc_verd: traffic control verdict
350 * @rxhash: the packet hash computed on receive
351 * @queue_mapping: Queue mapping for multiqueue devices
352 * @ndisc_nodetype: router type (from link layer)
353 * @ooo_okay: allow the mapping of a socket to a queue to be changed
354 * @l4_rxhash: indicate rxhash is a canonical 4-tuple hash over transport
356 * @dma_cookie: a cookie to one of several possible DMA operations
357 * done by skb DMA functions
358 * @secmark: security marking
359 * @mark: Generic packet mark
360 * @dropcount: total number of sk_receive_queue overflows
361 * @vlan_tci: vlan tag control information
362 * @transport_header: Transport layer header
363 * @network_header: Network layer header
364 * @mac_header: Link layer header
365 * @tail: Tail pointer
367 * @head: Head of buffer
368 * @data: Data head pointer
369 * @truesize: Buffer size
370 * @users: User count - see {datagram,tcp}.c
374 /* These two members must be first. */
375 struct sk_buff *next;
376 struct sk_buff *prev;
381 struct net_device *dev;
384 * This is the control buffer. It is free to use for every
385 * layer. Please put your private variables there. If you
386 * want to keep them across layers you have to do a skb_clone()
387 * first. This is owned by whoever has the skb queued ATM.
389 char cb[48] __aligned(8);
391 unsigned long _skb_refdst;
407 kmemcheck_bitfield_begin(flags1);
418 kmemcheck_bitfield_end(flags1);
421 void (*destructor)(struct sk_buff *skb);
422 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
423 struct nf_conntrack *nfct;
425 #ifdef NET_SKBUFF_NF_DEFRAG_NEEDED
426 struct sk_buff *nfct_reasm;
428 #ifdef CONFIG_BRIDGE_NETFILTER
429 struct nf_bridge_info *nf_bridge;
433 #ifdef CONFIG_NET_SCHED
434 __u16 tc_index; /* traffic control index */
435 #ifdef CONFIG_NET_CLS_ACT
436 __u16 tc_verd; /* traffic control verdict */
443 kmemcheck_bitfield_begin(flags2);
444 #ifdef CONFIG_IPV6_NDISC_NODETYPE
445 __u8 ndisc_nodetype:2;
449 kmemcheck_bitfield_end(flags2);
453 #ifdef CONFIG_NET_DMA
454 dma_cookie_t dma_cookie;
456 #ifdef CONFIG_NETWORK_SECMARK
466 sk_buff_data_t transport_header;
467 sk_buff_data_t network_header;
468 sk_buff_data_t mac_header;
469 /* These elements must be at the end, see alloc_skb() for details. */
474 unsigned int truesize;
480 * Handling routines are only of interest to the kernel
482 #include <linux/slab.h>
484 #include <asm/system.h>
487 * skb might have a dst pointer attached, refcounted or not.
488 * _skb_refdst low order bit is set if refcount was _not_ taken
490 #define SKB_DST_NOREF 1UL
491 #define SKB_DST_PTRMASK ~(SKB_DST_NOREF)
494 * skb_dst - returns skb dst_entry
497 * Returns skb dst_entry, regardless of reference taken or not.
499 static inline struct dst_entry *skb_dst(const struct sk_buff *skb)
501 /* If refdst was not refcounted, check we still are in a
502 * rcu_read_lock section
504 WARN_ON((skb->_skb_refdst & SKB_DST_NOREF) &&
505 !rcu_read_lock_held() &&
506 !rcu_read_lock_bh_held());
507 return (struct dst_entry *)(skb->_skb_refdst & SKB_DST_PTRMASK);
511 * skb_dst_set - sets skb dst
515 * Sets skb dst, assuming a reference was taken on dst and should
516 * be released by skb_dst_drop()
518 static inline void skb_dst_set(struct sk_buff *skb, struct dst_entry *dst)
520 skb->_skb_refdst = (unsigned long)dst;
523 extern void skb_dst_set_noref(struct sk_buff *skb, struct dst_entry *dst);
526 * skb_dst_is_noref - Test if skb dst isn't refcounted
529 static inline bool skb_dst_is_noref(const struct sk_buff *skb)
531 return (skb->_skb_refdst & SKB_DST_NOREF) && skb_dst(skb);
534 static inline struct rtable *skb_rtable(const struct sk_buff *skb)
536 return (struct rtable *)skb_dst(skb);
539 extern void kfree_skb(struct sk_buff *skb);
540 extern void consume_skb(struct sk_buff *skb);
541 extern void __kfree_skb(struct sk_buff *skb);
542 extern struct sk_buff *__alloc_skb(unsigned int size,
543 gfp_t priority, int fclone, int node);
544 extern struct sk_buff *build_skb(void *data);
545 static inline struct sk_buff *alloc_skb(unsigned int size,
548 return __alloc_skb(size, priority, 0, NUMA_NO_NODE);
551 static inline struct sk_buff *alloc_skb_fclone(unsigned int size,
554 return __alloc_skb(size, priority, 1, NUMA_NO_NODE);
557 extern void skb_recycle(struct sk_buff *skb);
558 extern bool skb_recycle_check(struct sk_buff *skb, int skb_size);
560 extern struct sk_buff *skb_morph(struct sk_buff *dst, struct sk_buff *src);
561 extern int skb_copy_ubufs(struct sk_buff *skb, gfp_t gfp_mask);
562 extern struct sk_buff *skb_clone(struct sk_buff *skb,
564 extern struct sk_buff *skb_copy(const struct sk_buff *skb,
566 extern struct sk_buff *pskb_copy(struct sk_buff *skb,
568 extern int pskb_expand_head(struct sk_buff *skb,
569 int nhead, int ntail,
571 extern struct sk_buff *skb_realloc_headroom(struct sk_buff *skb,
572 unsigned int headroom);
573 extern struct sk_buff *skb_copy_expand(const struct sk_buff *skb,
574 int newheadroom, int newtailroom,
576 extern int skb_to_sgvec(struct sk_buff *skb,
577 struct scatterlist *sg, int offset,
579 extern int skb_cow_data(struct sk_buff *skb, int tailbits,
580 struct sk_buff **trailer);
581 extern int skb_pad(struct sk_buff *skb, int pad);
582 #define dev_kfree_skb(a) consume_skb(a)
584 extern int skb_append_datato_frags(struct sock *sk, struct sk_buff *skb,
585 int getfrag(void *from, char *to, int offset,
586 int len,int odd, struct sk_buff *skb),
587 void *from, int length);
589 struct skb_seq_state {
593 __u32 stepped_offset;
594 struct sk_buff *root_skb;
595 struct sk_buff *cur_skb;
599 extern void skb_prepare_seq_read(struct sk_buff *skb,
600 unsigned int from, unsigned int to,
601 struct skb_seq_state *st);
602 extern unsigned int skb_seq_read(unsigned int consumed, const u8 **data,
603 struct skb_seq_state *st);
604 extern void skb_abort_seq_read(struct skb_seq_state *st);
606 extern unsigned int skb_find_text(struct sk_buff *skb, unsigned int from,
607 unsigned int to, struct ts_config *config,
608 struct ts_state *state);
610 extern void __skb_get_rxhash(struct sk_buff *skb);
611 static inline __u32 skb_get_rxhash(struct sk_buff *skb)
614 __skb_get_rxhash(skb);
619 #ifdef NET_SKBUFF_DATA_USES_OFFSET
620 static inline unsigned char *skb_end_pointer(const struct sk_buff *skb)
622 return skb->head + skb->end;
625 static inline unsigned char *skb_end_pointer(const struct sk_buff *skb)
632 #define skb_shinfo(SKB) ((struct skb_shared_info *)(skb_end_pointer(SKB)))
634 static inline struct skb_shared_hwtstamps *skb_hwtstamps(struct sk_buff *skb)
636 return &skb_shinfo(skb)->hwtstamps;
640 * skb_queue_empty - check if a queue is empty
643 * Returns true if the queue is empty, false otherwise.
645 static inline int skb_queue_empty(const struct sk_buff_head *list)
647 return list->next == (struct sk_buff *)list;
651 * skb_queue_is_last - check if skb is the last entry in the queue
655 * Returns true if @skb is the last buffer on the list.
657 static inline bool skb_queue_is_last(const struct sk_buff_head *list,
658 const struct sk_buff *skb)
660 return skb->next == (struct sk_buff *)list;
664 * skb_queue_is_first - check if skb is the first entry in the queue
668 * Returns true if @skb is the first buffer on the list.
670 static inline bool skb_queue_is_first(const struct sk_buff_head *list,
671 const struct sk_buff *skb)
673 return skb->prev == (struct sk_buff *)list;
677 * skb_queue_next - return the next packet in the queue
679 * @skb: current buffer
681 * Return the next packet in @list after @skb. It is only valid to
682 * call this if skb_queue_is_last() evaluates to false.
684 static inline struct sk_buff *skb_queue_next(const struct sk_buff_head *list,
685 const struct sk_buff *skb)
687 /* This BUG_ON may seem severe, but if we just return then we
688 * are going to dereference garbage.
690 BUG_ON(skb_queue_is_last(list, skb));
695 * skb_queue_prev - return the prev packet in the queue
697 * @skb: current buffer
699 * Return the prev packet in @list before @skb. It is only valid to
700 * call this if skb_queue_is_first() evaluates to false.
702 static inline struct sk_buff *skb_queue_prev(const struct sk_buff_head *list,
703 const struct sk_buff *skb)
705 /* This BUG_ON may seem severe, but if we just return then we
706 * are going to dereference garbage.
708 BUG_ON(skb_queue_is_first(list, skb));
713 * skb_get - reference buffer
714 * @skb: buffer to reference
716 * Makes another reference to a socket buffer and returns a pointer
719 static inline struct sk_buff *skb_get(struct sk_buff *skb)
721 atomic_inc(&skb->users);
726 * If users == 1, we are the only owner and are can avoid redundant
731 * skb_cloned - is the buffer a clone
732 * @skb: buffer to check
734 * Returns true if the buffer was generated with skb_clone() and is
735 * one of multiple shared copies of the buffer. Cloned buffers are
736 * shared data so must not be written to under normal circumstances.
738 static inline int skb_cloned(const struct sk_buff *skb)
740 return skb->cloned &&
741 (atomic_read(&skb_shinfo(skb)->dataref) & SKB_DATAREF_MASK) != 1;
745 * skb_header_cloned - is the header a clone
746 * @skb: buffer to check
748 * Returns true if modifying the header part of the buffer requires
749 * the data to be copied.
751 static inline int skb_header_cloned(const struct sk_buff *skb)
758 dataref = atomic_read(&skb_shinfo(skb)->dataref);
759 dataref = (dataref & SKB_DATAREF_MASK) - (dataref >> SKB_DATAREF_SHIFT);
764 * skb_header_release - release reference to header
765 * @skb: buffer to operate on
767 * Drop a reference to the header part of the buffer. This is done
768 * by acquiring a payload reference. You must not read from the header
769 * part of skb->data after this.
771 static inline void skb_header_release(struct sk_buff *skb)
775 atomic_add(1 << SKB_DATAREF_SHIFT, &skb_shinfo(skb)->dataref);
779 * skb_shared - is the buffer shared
780 * @skb: buffer to check
782 * Returns true if more than one person has a reference to this
785 static inline int skb_shared(const struct sk_buff *skb)
787 return atomic_read(&skb->users) != 1;
791 * skb_share_check - check if buffer is shared and if so clone it
792 * @skb: buffer to check
793 * @pri: priority for memory allocation
795 * If the buffer is shared the buffer is cloned and the old copy
796 * drops a reference. A new clone with a single reference is returned.
797 * If the buffer is not shared the original buffer is returned. When
798 * being called from interrupt status or with spinlocks held pri must
801 * NULL is returned on a memory allocation failure.
803 static inline struct sk_buff *skb_share_check(struct sk_buff *skb,
806 might_sleep_if(pri & __GFP_WAIT);
807 if (skb_shared(skb)) {
808 struct sk_buff *nskb = skb_clone(skb, pri);
816 * Copy shared buffers into a new sk_buff. We effectively do COW on
817 * packets to handle cases where we have a local reader and forward
818 * and a couple of other messy ones. The normal one is tcpdumping
819 * a packet thats being forwarded.
823 * skb_unshare - make a copy of a shared buffer
824 * @skb: buffer to check
825 * @pri: priority for memory allocation
827 * If the socket buffer is a clone then this function creates a new
828 * copy of the data, drops a reference count on the old copy and returns
829 * the new copy with the reference count at 1. If the buffer is not a clone
830 * the original buffer is returned. When called with a spinlock held or
831 * from interrupt state @pri must be %GFP_ATOMIC
833 * %NULL is returned on a memory allocation failure.
835 static inline struct sk_buff *skb_unshare(struct sk_buff *skb,
838 might_sleep_if(pri & __GFP_WAIT);
839 if (skb_cloned(skb)) {
840 struct sk_buff *nskb = skb_copy(skb, pri);
841 kfree_skb(skb); /* Free our shared copy */
848 * skb_peek - peek at the head of an &sk_buff_head
849 * @list_: list to peek at
851 * Peek an &sk_buff. Unlike most other operations you _MUST_
852 * be careful with this one. A peek leaves the buffer on the
853 * list and someone else may run off with it. You must hold
854 * the appropriate locks or have a private queue to do this.
856 * Returns %NULL for an empty list or a pointer to the head element.
857 * The reference count is not incremented and the reference is therefore
858 * volatile. Use with caution.
860 static inline struct sk_buff *skb_peek(const struct sk_buff_head *list_)
862 struct sk_buff *list = ((const struct sk_buff *)list_)->next;
863 if (list == (struct sk_buff *)list_)
869 * skb_peek_tail - peek at the tail of an &sk_buff_head
870 * @list_: list to peek at
872 * Peek an &sk_buff. Unlike most other operations you _MUST_
873 * be careful with this one. A peek leaves the buffer on the
874 * list and someone else may run off with it. You must hold
875 * the appropriate locks or have a private queue to do this.
877 * Returns %NULL for an empty list or a pointer to the tail element.
878 * The reference count is not incremented and the reference is therefore
879 * volatile. Use with caution.
881 static inline struct sk_buff *skb_peek_tail(const struct sk_buff_head *list_)
883 struct sk_buff *list = ((const struct sk_buff *)list_)->prev;
884 if (list == (struct sk_buff *)list_)
890 * skb_queue_len - get queue length
891 * @list_: list to measure
893 * Return the length of an &sk_buff queue.
895 static inline __u32 skb_queue_len(const struct sk_buff_head *list_)
901 * __skb_queue_head_init - initialize non-spinlock portions of sk_buff_head
902 * @list: queue to initialize
904 * This initializes only the list and queue length aspects of
905 * an sk_buff_head object. This allows to initialize the list
906 * aspects of an sk_buff_head without reinitializing things like
907 * the spinlock. It can also be used for on-stack sk_buff_head
908 * objects where the spinlock is known to not be used.
910 static inline void __skb_queue_head_init(struct sk_buff_head *list)
912 list->prev = list->next = (struct sk_buff *)list;
917 * This function creates a split out lock class for each invocation;
918 * this is needed for now since a whole lot of users of the skb-queue
919 * infrastructure in drivers have different locking usage (in hardirq)
920 * than the networking core (in softirq only). In the long run either the
921 * network layer or drivers should need annotation to consolidate the
922 * main types of usage into 3 classes.
924 static inline void skb_queue_head_init(struct sk_buff_head *list)
926 spin_lock_init(&list->lock);
927 __skb_queue_head_init(list);
930 static inline void skb_queue_head_init_class(struct sk_buff_head *list,
931 struct lock_class_key *class)
933 skb_queue_head_init(list);
934 lockdep_set_class(&list->lock, class);
938 * Insert an sk_buff on a list.
940 * The "__skb_xxxx()" functions are the non-atomic ones that
941 * can only be called with interrupts disabled.
943 extern void skb_insert(struct sk_buff *old, struct sk_buff *newsk, struct sk_buff_head *list);
944 static inline void __skb_insert(struct sk_buff *newsk,
945 struct sk_buff *prev, struct sk_buff *next,
946 struct sk_buff_head *list)
950 next->prev = prev->next = newsk;
954 static inline void __skb_queue_splice(const struct sk_buff_head *list,
955 struct sk_buff *prev,
956 struct sk_buff *next)
958 struct sk_buff *first = list->next;
959 struct sk_buff *last = list->prev;
969 * skb_queue_splice - join two skb lists, this is designed for stacks
970 * @list: the new list to add
971 * @head: the place to add it in the first list
973 static inline void skb_queue_splice(const struct sk_buff_head *list,
974 struct sk_buff_head *head)
976 if (!skb_queue_empty(list)) {
977 __skb_queue_splice(list, (struct sk_buff *) head, head->next);
978 head->qlen += list->qlen;
983 * skb_queue_splice - join two skb lists and reinitialise the emptied list
984 * @list: the new list to add
985 * @head: the place to add it in the first list
987 * The list at @list is reinitialised
989 static inline void skb_queue_splice_init(struct sk_buff_head *list,
990 struct sk_buff_head *head)
992 if (!skb_queue_empty(list)) {
993 __skb_queue_splice(list, (struct sk_buff *) head, head->next);
994 head->qlen += list->qlen;
995 __skb_queue_head_init(list);
1000 * skb_queue_splice_tail - join two skb lists, each list being a queue
1001 * @list: the new list to add
1002 * @head: the place to add it in the first list
1004 static inline void skb_queue_splice_tail(const struct sk_buff_head *list,
1005 struct sk_buff_head *head)
1007 if (!skb_queue_empty(list)) {
1008 __skb_queue_splice(list, head->prev, (struct sk_buff *) head);
1009 head->qlen += list->qlen;
1014 * skb_queue_splice_tail - join two skb lists and reinitialise the emptied list
1015 * @list: the new list to add
1016 * @head: the place to add it in the first list
1018 * Each of the lists is a queue.
1019 * The list at @list is reinitialised
1021 static inline void skb_queue_splice_tail_init(struct sk_buff_head *list,
1022 struct sk_buff_head *head)
1024 if (!skb_queue_empty(list)) {
1025 __skb_queue_splice(list, head->prev, (struct sk_buff *) head);
1026 head->qlen += list->qlen;
1027 __skb_queue_head_init(list);
1032 * __skb_queue_after - queue a buffer at the list head
1033 * @list: list to use
1034 * @prev: place after this buffer
1035 * @newsk: buffer to queue
1037 * Queue a buffer int the middle of a list. This function takes no locks
1038 * and you must therefore hold required locks before calling it.
1040 * A buffer cannot be placed on two lists at the same time.
1042 static inline void __skb_queue_after(struct sk_buff_head *list,
1043 struct sk_buff *prev,
1044 struct sk_buff *newsk)
1046 __skb_insert(newsk, prev, prev->next, list);
1049 extern void skb_append(struct sk_buff *old, struct sk_buff *newsk,
1050 struct sk_buff_head *list);
1052 static inline void __skb_queue_before(struct sk_buff_head *list,
1053 struct sk_buff *next,
1054 struct sk_buff *newsk)
1056 __skb_insert(newsk, next->prev, next, list);
1060 * __skb_queue_head - queue a buffer at the list head
1061 * @list: list to use
1062 * @newsk: buffer to queue
1064 * Queue a buffer at the start of a list. This function takes no locks
1065 * and you must therefore hold required locks before calling it.
1067 * A buffer cannot be placed on two lists at the same time.
1069 extern void skb_queue_head(struct sk_buff_head *list, struct sk_buff *newsk);
1070 static inline void __skb_queue_head(struct sk_buff_head *list,
1071 struct sk_buff *newsk)
1073 __skb_queue_after(list, (struct sk_buff *)list, newsk);
1077 * __skb_queue_tail - queue a buffer at the list tail
1078 * @list: list to use
1079 * @newsk: buffer to queue
1081 * Queue a buffer at the end of a list. This function takes no locks
1082 * and you must therefore hold required locks before calling it.
1084 * A buffer cannot be placed on two lists at the same time.
1086 extern void skb_queue_tail(struct sk_buff_head *list, struct sk_buff *newsk);
1087 static inline void __skb_queue_tail(struct sk_buff_head *list,
1088 struct sk_buff *newsk)
1090 __skb_queue_before(list, (struct sk_buff *)list, newsk);
1094 * remove sk_buff from list. _Must_ be called atomically, and with
1097 extern void skb_unlink(struct sk_buff *skb, struct sk_buff_head *list);
1098 static inline void __skb_unlink(struct sk_buff *skb, struct sk_buff_head *list)
1100 struct sk_buff *next, *prev;
1105 skb->next = skb->prev = NULL;
1111 * __skb_dequeue - remove from the head of the queue
1112 * @list: list to dequeue from
1114 * Remove the head of the list. This function does not take any locks
1115 * so must be used with appropriate locks held only. The head item is
1116 * returned or %NULL if the list is empty.
1118 extern struct sk_buff *skb_dequeue(struct sk_buff_head *list);
1119 static inline struct sk_buff *__skb_dequeue(struct sk_buff_head *list)
1121 struct sk_buff *skb = skb_peek(list);
1123 __skb_unlink(skb, list);
1128 * __skb_dequeue_tail - remove from the tail of the queue
1129 * @list: list to dequeue from
1131 * Remove the tail of the list. This function does not take any locks
1132 * so must be used with appropriate locks held only. The tail item is
1133 * returned or %NULL if the list is empty.
1135 extern struct sk_buff *skb_dequeue_tail(struct sk_buff_head *list);
1136 static inline struct sk_buff *__skb_dequeue_tail(struct sk_buff_head *list)
1138 struct sk_buff *skb = skb_peek_tail(list);
1140 __skb_unlink(skb, list);
1145 static inline int skb_is_nonlinear(const struct sk_buff *skb)
1147 return skb->data_len;
1150 static inline unsigned int skb_headlen(const struct sk_buff *skb)
1152 return skb->len - skb->data_len;
1155 static inline int skb_pagelen(const struct sk_buff *skb)
1159 for (i = (int)skb_shinfo(skb)->nr_frags - 1; i >= 0; i--)
1160 len += skb_frag_size(&skb_shinfo(skb)->frags[i]);
1161 return len + skb_headlen(skb);
1165 * __skb_fill_page_desc - initialise a paged fragment in an skb
1166 * @skb: buffer containing fragment to be initialised
1167 * @i: paged fragment index to initialise
1168 * @page: the page to use for this fragment
1169 * @off: the offset to the data with @page
1170 * @size: the length of the data
1172 * Initialises the @i'th fragment of @skb to point to &size bytes at
1173 * offset @off within @page.
1175 * Does not take any additional reference on the fragment.
1177 static inline void __skb_fill_page_desc(struct sk_buff *skb, int i,
1178 struct page *page, int off, int size)
1180 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
1182 frag->page.p = page;
1183 frag->page_offset = off;
1184 skb_frag_size_set(frag, size);
1188 * skb_fill_page_desc - initialise a paged fragment in an skb
1189 * @skb: buffer containing fragment to be initialised
1190 * @i: paged fragment index to initialise
1191 * @page: the page to use for this fragment
1192 * @off: the offset to the data with @page
1193 * @size: the length of the data
1195 * As per __skb_fill_page_desc() -- initialises the @i'th fragment of
1196 * @skb to point to &size bytes at offset @off within @page. In
1197 * addition updates @skb such that @i is the last fragment.
1199 * Does not take any additional reference on the fragment.
1201 static inline void skb_fill_page_desc(struct sk_buff *skb, int i,
1202 struct page *page, int off, int size)
1204 __skb_fill_page_desc(skb, i, page, off, size);
1205 skb_shinfo(skb)->nr_frags = i + 1;
1208 extern void skb_add_rx_frag(struct sk_buff *skb, int i, struct page *page,
1211 #define SKB_PAGE_ASSERT(skb) BUG_ON(skb_shinfo(skb)->nr_frags)
1212 #define SKB_FRAG_ASSERT(skb) BUG_ON(skb_has_frag_list(skb))
1213 #define SKB_LINEAR_ASSERT(skb) BUG_ON(skb_is_nonlinear(skb))
1215 #ifdef NET_SKBUFF_DATA_USES_OFFSET
1216 static inline unsigned char *skb_tail_pointer(const struct sk_buff *skb)
1218 return skb->head + skb->tail;
1221 static inline void skb_reset_tail_pointer(struct sk_buff *skb)
1223 skb->tail = skb->data - skb->head;
1226 static inline void skb_set_tail_pointer(struct sk_buff *skb, const int offset)
1228 skb_reset_tail_pointer(skb);
1229 skb->tail += offset;
1231 #else /* NET_SKBUFF_DATA_USES_OFFSET */
1232 static inline unsigned char *skb_tail_pointer(const struct sk_buff *skb)
1237 static inline void skb_reset_tail_pointer(struct sk_buff *skb)
1239 skb->tail = skb->data;
1242 static inline void skb_set_tail_pointer(struct sk_buff *skb, const int offset)
1244 skb->tail = skb->data + offset;
1247 #endif /* NET_SKBUFF_DATA_USES_OFFSET */
1250 * Add data to an sk_buff
1252 extern unsigned char *skb_put(struct sk_buff *skb, unsigned int len);
1253 static inline unsigned char *__skb_put(struct sk_buff *skb, unsigned int len)
1255 unsigned char *tmp = skb_tail_pointer(skb);
1256 SKB_LINEAR_ASSERT(skb);
1262 extern unsigned char *skb_push(struct sk_buff *skb, unsigned int len);
1263 static inline unsigned char *__skb_push(struct sk_buff *skb, unsigned int len)
1270 extern unsigned char *skb_pull(struct sk_buff *skb, unsigned int len);
1271 static inline unsigned char *__skb_pull(struct sk_buff *skb, unsigned int len)
1274 BUG_ON(skb->len < skb->data_len);
1275 return skb->data += len;
1278 static inline unsigned char *skb_pull_inline(struct sk_buff *skb, unsigned int len)
1280 return unlikely(len > skb->len) ? NULL : __skb_pull(skb, len);
1283 extern unsigned char *__pskb_pull_tail(struct sk_buff *skb, int delta);
1285 static inline unsigned char *__pskb_pull(struct sk_buff *skb, unsigned int len)
1287 if (len > skb_headlen(skb) &&
1288 !__pskb_pull_tail(skb, len - skb_headlen(skb)))
1291 return skb->data += len;
1294 static inline unsigned char *pskb_pull(struct sk_buff *skb, unsigned int len)
1296 return unlikely(len > skb->len) ? NULL : __pskb_pull(skb, len);
1299 static inline int pskb_may_pull(struct sk_buff *skb, unsigned int len)
1301 if (likely(len <= skb_headlen(skb)))
1303 if (unlikely(len > skb->len))
1305 return __pskb_pull_tail(skb, len - skb_headlen(skb)) != NULL;
1309 * skb_headroom - bytes at buffer head
1310 * @skb: buffer to check
1312 * Return the number of bytes of free space at the head of an &sk_buff.
1314 static inline unsigned int skb_headroom(const struct sk_buff *skb)
1316 return skb->data - skb->head;
1320 * skb_tailroom - bytes at buffer end
1321 * @skb: buffer to check
1323 * Return the number of bytes of free space at the tail of an sk_buff
1325 static inline int skb_tailroom(const struct sk_buff *skb)
1327 return skb_is_nonlinear(skb) ? 0 : skb->end - skb->tail;
1331 * skb_reserve - adjust headroom
1332 * @skb: buffer to alter
1333 * @len: bytes to move
1335 * Increase the headroom of an empty &sk_buff by reducing the tail
1336 * room. This is only allowed for an empty buffer.
1338 static inline void skb_reserve(struct sk_buff *skb, int len)
1344 static inline void skb_reset_mac_len(struct sk_buff *skb)
1346 skb->mac_len = skb->network_header - skb->mac_header;
1349 #ifdef NET_SKBUFF_DATA_USES_OFFSET
1350 static inline unsigned char *skb_transport_header(const struct sk_buff *skb)
1352 return skb->head + skb->transport_header;
1355 static inline void skb_reset_transport_header(struct sk_buff *skb)
1357 skb->transport_header = skb->data - skb->head;
1360 static inline void skb_set_transport_header(struct sk_buff *skb,
1363 skb_reset_transport_header(skb);
1364 skb->transport_header += offset;
1367 static inline unsigned char *skb_network_header(const struct sk_buff *skb)
1369 return skb->head + skb->network_header;
1372 static inline void skb_reset_network_header(struct sk_buff *skb)
1374 skb->network_header = skb->data - skb->head;
1377 static inline void skb_set_network_header(struct sk_buff *skb, const int offset)
1379 skb_reset_network_header(skb);
1380 skb->network_header += offset;
1383 static inline unsigned char *skb_mac_header(const struct sk_buff *skb)
1385 return skb->head + skb->mac_header;
1388 static inline int skb_mac_header_was_set(const struct sk_buff *skb)
1390 return skb->mac_header != ~0U;
1393 static inline void skb_reset_mac_header(struct sk_buff *skb)
1395 skb->mac_header = skb->data - skb->head;
1398 static inline void skb_set_mac_header(struct sk_buff *skb, const int offset)
1400 skb_reset_mac_header(skb);
1401 skb->mac_header += offset;
1404 #else /* NET_SKBUFF_DATA_USES_OFFSET */
1406 static inline unsigned char *skb_transport_header(const struct sk_buff *skb)
1408 return skb->transport_header;
1411 static inline void skb_reset_transport_header(struct sk_buff *skb)
1413 skb->transport_header = skb->data;
1416 static inline void skb_set_transport_header(struct sk_buff *skb,
1419 skb->transport_header = skb->data + offset;
1422 static inline unsigned char *skb_network_header(const struct sk_buff *skb)
1424 return skb->network_header;
1427 static inline void skb_reset_network_header(struct sk_buff *skb)
1429 skb->network_header = skb->data;
1432 static inline void skb_set_network_header(struct sk_buff *skb, const int offset)
1434 skb->network_header = skb->data + offset;
1437 static inline unsigned char *skb_mac_header(const struct sk_buff *skb)
1439 return skb->mac_header;
1442 static inline int skb_mac_header_was_set(const struct sk_buff *skb)
1444 return skb->mac_header != NULL;
1447 static inline void skb_reset_mac_header(struct sk_buff *skb)
1449 skb->mac_header = skb->data;
1452 static inline void skb_set_mac_header(struct sk_buff *skb, const int offset)
1454 skb->mac_header = skb->data + offset;
1456 #endif /* NET_SKBUFF_DATA_USES_OFFSET */
1458 static inline int skb_checksum_start_offset(const struct sk_buff *skb)
1460 return skb->csum_start - skb_headroom(skb);
1463 static inline int skb_transport_offset(const struct sk_buff *skb)
1465 return skb_transport_header(skb) - skb->data;
1468 static inline u32 skb_network_header_len(const struct sk_buff *skb)
1470 return skb->transport_header - skb->network_header;
1473 static inline int skb_network_offset(const struct sk_buff *skb)
1475 return skb_network_header(skb) - skb->data;
1478 static inline int pskb_network_may_pull(struct sk_buff *skb, unsigned int len)
1480 return pskb_may_pull(skb, skb_network_offset(skb) + len);
1484 * CPUs often take a performance hit when accessing unaligned memory
1485 * locations. The actual performance hit varies, it can be small if the
1486 * hardware handles it or large if we have to take an exception and fix it
1489 * Since an ethernet header is 14 bytes network drivers often end up with
1490 * the IP header at an unaligned offset. The IP header can be aligned by
1491 * shifting the start of the packet by 2 bytes. Drivers should do this
1494 * skb_reserve(skb, NET_IP_ALIGN);
1496 * The downside to this alignment of the IP header is that the DMA is now
1497 * unaligned. On some architectures the cost of an unaligned DMA is high
1498 * and this cost outweighs the gains made by aligning the IP header.
1500 * Since this trade off varies between architectures, we allow NET_IP_ALIGN
1503 #ifndef NET_IP_ALIGN
1504 #define NET_IP_ALIGN 2
1508 * The networking layer reserves some headroom in skb data (via
1509 * dev_alloc_skb). This is used to avoid having to reallocate skb data when
1510 * the header has to grow. In the default case, if the header has to grow
1511 * 32 bytes or less we avoid the reallocation.
1513 * Unfortunately this headroom changes the DMA alignment of the resulting
1514 * network packet. As for NET_IP_ALIGN, this unaligned DMA is expensive
1515 * on some architectures. An architecture can override this value,
1516 * perhaps setting it to a cacheline in size (since that will maintain
1517 * cacheline alignment of the DMA). It must be a power of 2.
1519 * Various parts of the networking layer expect at least 32 bytes of
1520 * headroom, you should not reduce this.
1522 * Using max(32, L1_CACHE_BYTES) makes sense (especially with RPS)
1523 * to reduce average number of cache lines per packet.
1524 * get_rps_cpus() for example only access one 64 bytes aligned block :
1525 * NET_IP_ALIGN(2) + ethernet_header(14) + IP_header(20/40) + ports(8)
1528 #define NET_SKB_PAD max(32, L1_CACHE_BYTES)
1531 extern int ___pskb_trim(struct sk_buff *skb, unsigned int len);
1533 static inline void __skb_trim(struct sk_buff *skb, unsigned int len)
1535 if (unlikely(skb_is_nonlinear(skb))) {
1540 skb_set_tail_pointer(skb, len);
1543 extern void skb_trim(struct sk_buff *skb, unsigned int len);
1545 static inline int __pskb_trim(struct sk_buff *skb, unsigned int len)
1548 return ___pskb_trim(skb, len);
1549 __skb_trim(skb, len);
1553 static inline int pskb_trim(struct sk_buff *skb, unsigned int len)
1555 return (len < skb->len) ? __pskb_trim(skb, len) : 0;
1559 * pskb_trim_unique - remove end from a paged unique (not cloned) buffer
1560 * @skb: buffer to alter
1563 * This is identical to pskb_trim except that the caller knows that
1564 * the skb is not cloned so we should never get an error due to out-
1567 static inline void pskb_trim_unique(struct sk_buff *skb, unsigned int len)
1569 int err = pskb_trim(skb, len);
1574 * skb_orphan - orphan a buffer
1575 * @skb: buffer to orphan
1577 * If a buffer currently has an owner then we call the owner's
1578 * destructor function and make the @skb unowned. The buffer continues
1579 * to exist but is no longer charged to its former owner.
1581 static inline void skb_orphan(struct sk_buff *skb)
1583 if (skb->destructor)
1584 skb->destructor(skb);
1585 skb->destructor = NULL;
1590 * __skb_queue_purge - empty a list
1591 * @list: list to empty
1593 * Delete all buffers on an &sk_buff list. Each buffer is removed from
1594 * the list and one reference dropped. This function does not take the
1595 * list lock and the caller must hold the relevant locks to use it.
1597 extern void skb_queue_purge(struct sk_buff_head *list);
1598 static inline void __skb_queue_purge(struct sk_buff_head *list)
1600 struct sk_buff *skb;
1601 while ((skb = __skb_dequeue(list)) != NULL)
1606 * __dev_alloc_skb - allocate an skbuff for receiving
1607 * @length: length to allocate
1608 * @gfp_mask: get_free_pages mask, passed to alloc_skb
1610 * Allocate a new &sk_buff and assign it a usage count of one. The
1611 * buffer has unspecified headroom built in. Users should allocate
1612 * the headroom they think they need without accounting for the
1613 * built in space. The built in space is used for optimisations.
1615 * %NULL is returned if there is no free memory.
1617 static inline struct sk_buff *__dev_alloc_skb(unsigned int length,
1620 struct sk_buff *skb = alloc_skb(length + NET_SKB_PAD, gfp_mask);
1622 skb_reserve(skb, NET_SKB_PAD);
1626 extern struct sk_buff *dev_alloc_skb(unsigned int length);
1628 extern struct sk_buff *__netdev_alloc_skb(struct net_device *dev,
1629 unsigned int length, gfp_t gfp_mask);
1632 * netdev_alloc_skb - allocate an skbuff for rx on a specific device
1633 * @dev: network device to receive on
1634 * @length: length to allocate
1636 * Allocate a new &sk_buff and assign it a usage count of one. The
1637 * buffer has unspecified headroom built in. Users should allocate
1638 * the headroom they think they need without accounting for the
1639 * built in space. The built in space is used for optimisations.
1641 * %NULL is returned if there is no free memory. Although this function
1642 * allocates memory it can be called from an interrupt.
1644 static inline struct sk_buff *netdev_alloc_skb(struct net_device *dev,
1645 unsigned int length)
1647 return __netdev_alloc_skb(dev, length, GFP_ATOMIC);
1650 static inline struct sk_buff *__netdev_alloc_skb_ip_align(struct net_device *dev,
1651 unsigned int length, gfp_t gfp)
1653 struct sk_buff *skb = __netdev_alloc_skb(dev, length + NET_IP_ALIGN, gfp);
1655 if (NET_IP_ALIGN && skb)
1656 skb_reserve(skb, NET_IP_ALIGN);
1660 static inline struct sk_buff *netdev_alloc_skb_ip_align(struct net_device *dev,
1661 unsigned int length)
1663 return __netdev_alloc_skb_ip_align(dev, length, GFP_ATOMIC);
1667 * __netdev_alloc_page - allocate a page for ps-rx on a specific device
1668 * @dev: network device to receive on
1669 * @gfp_mask: alloc_pages_node mask
1671 * Allocate a new page. dev currently unused.
1673 * %NULL is returned if there is no free memory.
1675 static inline struct page *__netdev_alloc_page(struct net_device *dev, gfp_t gfp_mask)
1677 return alloc_pages_node(NUMA_NO_NODE, gfp_mask, 0);
1681 * netdev_alloc_page - allocate a page for ps-rx on a specific device
1682 * @dev: network device to receive on
1684 * Allocate a new page. dev currently unused.
1686 * %NULL is returned if there is no free memory.
1688 static inline struct page *netdev_alloc_page(struct net_device *dev)
1690 return __netdev_alloc_page(dev, GFP_ATOMIC);
1693 static inline void netdev_free_page(struct net_device *dev, struct page *page)
1699 * skb_frag_page - retrieve the page refered to by a paged fragment
1700 * @frag: the paged fragment
1702 * Returns the &struct page associated with @frag.
1704 static inline struct page *skb_frag_page(const skb_frag_t *frag)
1706 return frag->page.p;
1710 * __skb_frag_ref - take an addition reference on a paged fragment.
1711 * @frag: the paged fragment
1713 * Takes an additional reference on the paged fragment @frag.
1715 static inline void __skb_frag_ref(skb_frag_t *frag)
1717 get_page(skb_frag_page(frag));
1721 * skb_frag_ref - take an addition reference on a paged fragment of an skb.
1723 * @f: the fragment offset.
1725 * Takes an additional reference on the @f'th paged fragment of @skb.
1727 static inline void skb_frag_ref(struct sk_buff *skb, int f)
1729 __skb_frag_ref(&skb_shinfo(skb)->frags[f]);
1733 * __skb_frag_unref - release a reference on a paged fragment.
1734 * @frag: the paged fragment
1736 * Releases a reference on the paged fragment @frag.
1738 static inline void __skb_frag_unref(skb_frag_t *frag)
1740 put_page(skb_frag_page(frag));
1744 * skb_frag_unref - release a reference on a paged fragment of an skb.
1746 * @f: the fragment offset
1748 * Releases a reference on the @f'th paged fragment of @skb.
1750 static inline void skb_frag_unref(struct sk_buff *skb, int f)
1752 __skb_frag_unref(&skb_shinfo(skb)->frags[f]);
1756 * skb_frag_address - gets the address of the data contained in a paged fragment
1757 * @frag: the paged fragment buffer
1759 * Returns the address of the data within @frag. The page must already
1762 static inline void *skb_frag_address(const skb_frag_t *frag)
1764 return page_address(skb_frag_page(frag)) + frag->page_offset;
1768 * skb_frag_address_safe - gets the address of the data contained in a paged fragment
1769 * @frag: the paged fragment buffer
1771 * Returns the address of the data within @frag. Checks that the page
1772 * is mapped and returns %NULL otherwise.
1774 static inline void *skb_frag_address_safe(const skb_frag_t *frag)
1776 void *ptr = page_address(skb_frag_page(frag));
1780 return ptr + frag->page_offset;
1784 * __skb_frag_set_page - sets the page contained in a paged fragment
1785 * @frag: the paged fragment
1786 * @page: the page to set
1788 * Sets the fragment @frag to contain @page.
1790 static inline void __skb_frag_set_page(skb_frag_t *frag, struct page *page)
1792 frag->page.p = page;
1796 * skb_frag_set_page - sets the page contained in a paged fragment of an skb
1798 * @f: the fragment offset
1799 * @page: the page to set
1801 * Sets the @f'th fragment of @skb to contain @page.
1803 static inline void skb_frag_set_page(struct sk_buff *skb, int f,
1806 __skb_frag_set_page(&skb_shinfo(skb)->frags[f], page);
1810 * skb_frag_dma_map - maps a paged fragment via the DMA API
1811 * @dev: the device to map the fragment to
1812 * @frag: the paged fragment to map
1813 * @offset: the offset within the fragment (starting at the
1814 * fragment's own offset)
1815 * @size: the number of bytes to map
1816 * @dir: the direction of the mapping (%PCI_DMA_*)
1818 * Maps the page associated with @frag to @device.
1820 static inline dma_addr_t skb_frag_dma_map(struct device *dev,
1821 const skb_frag_t *frag,
1822 size_t offset, size_t size,
1823 enum dma_data_direction dir)
1825 return dma_map_page(dev, skb_frag_page(frag),
1826 frag->page_offset + offset, size, dir);
1830 * skb_clone_writable - is the header of a clone writable
1831 * @skb: buffer to check
1832 * @len: length up to which to write
1834 * Returns true if modifying the header part of the cloned buffer
1835 * does not requires the data to be copied.
1837 static inline int skb_clone_writable(const struct sk_buff *skb, unsigned int len)
1839 return !skb_header_cloned(skb) &&
1840 skb_headroom(skb) + len <= skb->hdr_len;
1843 static inline int __skb_cow(struct sk_buff *skb, unsigned int headroom,
1848 if (headroom < NET_SKB_PAD)
1849 headroom = NET_SKB_PAD;
1850 if (headroom > skb_headroom(skb))
1851 delta = headroom - skb_headroom(skb);
1853 if (delta || cloned)
1854 return pskb_expand_head(skb, ALIGN(delta, NET_SKB_PAD), 0,
1860 * skb_cow - copy header of skb when it is required
1861 * @skb: buffer to cow
1862 * @headroom: needed headroom
1864 * If the skb passed lacks sufficient headroom or its data part
1865 * is shared, data is reallocated. If reallocation fails, an error
1866 * is returned and original skb is not changed.
1868 * The result is skb with writable area skb->head...skb->tail
1869 * and at least @headroom of space at head.
1871 static inline int skb_cow(struct sk_buff *skb, unsigned int headroom)
1873 return __skb_cow(skb, headroom, skb_cloned(skb));
1877 * skb_cow_head - skb_cow but only making the head writable
1878 * @skb: buffer to cow
1879 * @headroom: needed headroom
1881 * This function is identical to skb_cow except that we replace the
1882 * skb_cloned check by skb_header_cloned. It should be used when
1883 * you only need to push on some header and do not need to modify
1886 static inline int skb_cow_head(struct sk_buff *skb, unsigned int headroom)
1888 return __skb_cow(skb, headroom, skb_header_cloned(skb));
1892 * skb_padto - pad an skbuff up to a minimal size
1893 * @skb: buffer to pad
1894 * @len: minimal length
1896 * Pads up a buffer to ensure the trailing bytes exist and are
1897 * blanked. If the buffer already contains sufficient data it
1898 * is untouched. Otherwise it is extended. Returns zero on
1899 * success. The skb is freed on error.
1902 static inline int skb_padto(struct sk_buff *skb, unsigned int len)
1904 unsigned int size = skb->len;
1905 if (likely(size >= len))
1907 return skb_pad(skb, len - size);
1910 static inline int skb_add_data(struct sk_buff *skb,
1911 char __user *from, int copy)
1913 const int off = skb->len;
1915 if (skb->ip_summed == CHECKSUM_NONE) {
1917 __wsum csum = csum_and_copy_from_user(from, skb_put(skb, copy),
1920 skb->csum = csum_block_add(skb->csum, csum, off);
1923 } else if (!copy_from_user(skb_put(skb, copy), from, copy))
1926 __skb_trim(skb, off);
1930 static inline int skb_can_coalesce(struct sk_buff *skb, int i,
1931 const struct page *page, int off)
1934 const struct skb_frag_struct *frag = &skb_shinfo(skb)->frags[i - 1];
1936 return page == skb_frag_page(frag) &&
1937 off == frag->page_offset + skb_frag_size(frag);
1942 static inline int __skb_linearize(struct sk_buff *skb)
1944 return __pskb_pull_tail(skb, skb->data_len) ? 0 : -ENOMEM;
1948 * skb_linearize - convert paged skb to linear one
1949 * @skb: buffer to linarize
1951 * If there is no free memory -ENOMEM is returned, otherwise zero
1952 * is returned and the old skb data released.
1954 static inline int skb_linearize(struct sk_buff *skb)
1956 return skb_is_nonlinear(skb) ? __skb_linearize(skb) : 0;
1960 * skb_linearize_cow - make sure skb is linear and writable
1961 * @skb: buffer to process
1963 * If there is no free memory -ENOMEM is returned, otherwise zero
1964 * is returned and the old skb data released.
1966 static inline int skb_linearize_cow(struct sk_buff *skb)
1968 return skb_is_nonlinear(skb) || skb_cloned(skb) ?
1969 __skb_linearize(skb) : 0;
1973 * skb_postpull_rcsum - update checksum for received skb after pull
1974 * @skb: buffer to update
1975 * @start: start of data before pull
1976 * @len: length of data pulled
1978 * After doing a pull on a received packet, you need to call this to
1979 * update the CHECKSUM_COMPLETE checksum, or set ip_summed to
1980 * CHECKSUM_NONE so that it can be recomputed from scratch.
1983 static inline void skb_postpull_rcsum(struct sk_buff *skb,
1984 const void *start, unsigned int len)
1986 if (skb->ip_summed == CHECKSUM_COMPLETE)
1987 skb->csum = csum_sub(skb->csum, csum_partial(start, len, 0));
1990 unsigned char *skb_pull_rcsum(struct sk_buff *skb, unsigned int len);
1993 * pskb_trim_rcsum - trim received skb and update checksum
1994 * @skb: buffer to trim
1997 * This is exactly the same as pskb_trim except that it ensures the
1998 * checksum of received packets are still valid after the operation.
2001 static inline int pskb_trim_rcsum(struct sk_buff *skb, unsigned int len)
2003 if (likely(len >= skb->len))
2005 if (skb->ip_summed == CHECKSUM_COMPLETE)
2006 skb->ip_summed = CHECKSUM_NONE;
2007 return __pskb_trim(skb, len);
2010 #define skb_queue_walk(queue, skb) \
2011 for (skb = (queue)->next; \
2012 skb != (struct sk_buff *)(queue); \
2015 #define skb_queue_walk_safe(queue, skb, tmp) \
2016 for (skb = (queue)->next, tmp = skb->next; \
2017 skb != (struct sk_buff *)(queue); \
2018 skb = tmp, tmp = skb->next)
2020 #define skb_queue_walk_from(queue, skb) \
2021 for (; skb != (struct sk_buff *)(queue); \
2024 #define skb_queue_walk_from_safe(queue, skb, tmp) \
2025 for (tmp = skb->next; \
2026 skb != (struct sk_buff *)(queue); \
2027 skb = tmp, tmp = skb->next)
2029 #define skb_queue_reverse_walk(queue, skb) \
2030 for (skb = (queue)->prev; \
2031 skb != (struct sk_buff *)(queue); \
2034 #define skb_queue_reverse_walk_safe(queue, skb, tmp) \
2035 for (skb = (queue)->prev, tmp = skb->prev; \
2036 skb != (struct sk_buff *)(queue); \
2037 skb = tmp, tmp = skb->prev)
2039 #define skb_queue_reverse_walk_from_safe(queue, skb, tmp) \
2040 for (tmp = skb->prev; \
2041 skb != (struct sk_buff *)(queue); \
2042 skb = tmp, tmp = skb->prev)
2044 static inline bool skb_has_frag_list(const struct sk_buff *skb)
2046 return skb_shinfo(skb)->frag_list != NULL;
2049 static inline void skb_frag_list_init(struct sk_buff *skb)
2051 skb_shinfo(skb)->frag_list = NULL;
2054 static inline void skb_frag_add_head(struct sk_buff *skb, struct sk_buff *frag)
2056 frag->next = skb_shinfo(skb)->frag_list;
2057 skb_shinfo(skb)->frag_list = frag;
2060 #define skb_walk_frags(skb, iter) \
2061 for (iter = skb_shinfo(skb)->frag_list; iter; iter = iter->next)
2063 extern struct sk_buff *__skb_recv_datagram(struct sock *sk, unsigned flags,
2064 int *peeked, int *err);
2065 extern struct sk_buff *skb_recv_datagram(struct sock *sk, unsigned flags,
2066 int noblock, int *err);
2067 extern unsigned int datagram_poll(struct file *file, struct socket *sock,
2068 struct poll_table_struct *wait);
2069 extern int skb_copy_datagram_iovec(const struct sk_buff *from,
2070 int offset, struct iovec *to,
2072 extern int skb_copy_and_csum_datagram_iovec(struct sk_buff *skb,
2075 extern int skb_copy_datagram_from_iovec(struct sk_buff *skb,
2077 const struct iovec *from,
2080 extern int skb_copy_datagram_const_iovec(const struct sk_buff *from,
2082 const struct iovec *to,
2085 extern void skb_free_datagram(struct sock *sk, struct sk_buff *skb);
2086 extern void skb_free_datagram_locked(struct sock *sk,
2087 struct sk_buff *skb);
2088 extern int skb_kill_datagram(struct sock *sk, struct sk_buff *skb,
2089 unsigned int flags);
2090 extern __wsum skb_checksum(const struct sk_buff *skb, int offset,
2091 int len, __wsum csum);
2092 extern int skb_copy_bits(const struct sk_buff *skb, int offset,
2094 extern int skb_store_bits(struct sk_buff *skb, int offset,
2095 const void *from, int len);
2096 extern __wsum skb_copy_and_csum_bits(const struct sk_buff *skb,
2097 int offset, u8 *to, int len,
2099 extern int skb_splice_bits(struct sk_buff *skb,
2100 unsigned int offset,
2101 struct pipe_inode_info *pipe,
2103 unsigned int flags);
2104 extern void skb_copy_and_csum_dev(const struct sk_buff *skb, u8 *to);
2105 extern void skb_split(struct sk_buff *skb,
2106 struct sk_buff *skb1, const u32 len);
2107 extern int skb_shift(struct sk_buff *tgt, struct sk_buff *skb,
2110 extern struct sk_buff *skb_segment(struct sk_buff *skb,
2111 netdev_features_t features);
2113 static inline void *skb_header_pointer(const struct sk_buff *skb, int offset,
2114 int len, void *buffer)
2116 int hlen = skb_headlen(skb);
2118 if (hlen - offset >= len)
2119 return skb->data + offset;
2121 if (skb_copy_bits(skb, offset, buffer, len) < 0)
2127 static inline void skb_copy_from_linear_data(const struct sk_buff *skb,
2129 const unsigned int len)
2131 memcpy(to, skb->data, len);
2134 static inline void skb_copy_from_linear_data_offset(const struct sk_buff *skb,
2135 const int offset, void *to,
2136 const unsigned int len)
2138 memcpy(to, skb->data + offset, len);
2141 static inline void skb_copy_to_linear_data(struct sk_buff *skb,
2143 const unsigned int len)
2145 memcpy(skb->data, from, len);
2148 static inline void skb_copy_to_linear_data_offset(struct sk_buff *skb,
2151 const unsigned int len)
2153 memcpy(skb->data + offset, from, len);
2156 extern void skb_init(void);
2158 static inline ktime_t skb_get_ktime(const struct sk_buff *skb)
2164 * skb_get_timestamp - get timestamp from a skb
2165 * @skb: skb to get stamp from
2166 * @stamp: pointer to struct timeval to store stamp in
2168 * Timestamps are stored in the skb as offsets to a base timestamp.
2169 * This function converts the offset back to a struct timeval and stores
2172 static inline void skb_get_timestamp(const struct sk_buff *skb,
2173 struct timeval *stamp)
2175 *stamp = ktime_to_timeval(skb->tstamp);
2178 static inline void skb_get_timestampns(const struct sk_buff *skb,
2179 struct timespec *stamp)
2181 *stamp = ktime_to_timespec(skb->tstamp);
2184 static inline void __net_timestamp(struct sk_buff *skb)
2186 skb->tstamp = ktime_get_real();
2189 static inline ktime_t net_timedelta(ktime_t t)
2191 return ktime_sub(ktime_get_real(), t);
2194 static inline ktime_t net_invalid_timestamp(void)
2196 return ktime_set(0, 0);
2199 extern void skb_timestamping_init(void);
2201 #ifdef CONFIG_NETWORK_PHY_TIMESTAMPING
2203 extern void skb_clone_tx_timestamp(struct sk_buff *skb);
2204 extern bool skb_defer_rx_timestamp(struct sk_buff *skb);
2206 #else /* CONFIG_NETWORK_PHY_TIMESTAMPING */
2208 static inline void skb_clone_tx_timestamp(struct sk_buff *skb)
2212 static inline bool skb_defer_rx_timestamp(struct sk_buff *skb)
2217 #endif /* !CONFIG_NETWORK_PHY_TIMESTAMPING */
2220 * skb_complete_tx_timestamp() - deliver cloned skb with tx timestamps
2222 * PHY drivers may accept clones of transmitted packets for
2223 * timestamping via their phy_driver.txtstamp method. These drivers
2224 * must call this function to return the skb back to the stack, with
2225 * or without a timestamp.
2227 * @skb: clone of the the original outgoing packet
2228 * @hwtstamps: hardware time stamps, may be NULL if not available
2231 void skb_complete_tx_timestamp(struct sk_buff *skb,
2232 struct skb_shared_hwtstamps *hwtstamps);
2235 * skb_tstamp_tx - queue clone of skb with send time stamps
2236 * @orig_skb: the original outgoing packet
2237 * @hwtstamps: hardware time stamps, may be NULL if not available
2239 * If the skb has a socket associated, then this function clones the
2240 * skb (thus sharing the actual data and optional structures), stores
2241 * the optional hardware time stamping information (if non NULL) or
2242 * generates a software time stamp (otherwise), then queues the clone
2243 * to the error queue of the socket. Errors are silently ignored.
2245 extern void skb_tstamp_tx(struct sk_buff *orig_skb,
2246 struct skb_shared_hwtstamps *hwtstamps);
2248 static inline void sw_tx_timestamp(struct sk_buff *skb)
2250 if (skb_shinfo(skb)->tx_flags & SKBTX_SW_TSTAMP &&
2251 !(skb_shinfo(skb)->tx_flags & SKBTX_IN_PROGRESS))
2252 skb_tstamp_tx(skb, NULL);
2256 * skb_tx_timestamp() - Driver hook for transmit timestamping
2258 * Ethernet MAC Drivers should call this function in their hard_xmit()
2259 * function immediately before giving the sk_buff to the MAC hardware.
2261 * @skb: A socket buffer.
2263 static inline void skb_tx_timestamp(struct sk_buff *skb)
2265 skb_clone_tx_timestamp(skb);
2266 sw_tx_timestamp(skb);
2269 extern __sum16 __skb_checksum_complete_head(struct sk_buff *skb, int len);
2270 extern __sum16 __skb_checksum_complete(struct sk_buff *skb);
2272 static inline int skb_csum_unnecessary(const struct sk_buff *skb)
2274 return skb->ip_summed & CHECKSUM_UNNECESSARY;
2278 * skb_checksum_complete - Calculate checksum of an entire packet
2279 * @skb: packet to process
2281 * This function calculates the checksum over the entire packet plus
2282 * the value of skb->csum. The latter can be used to supply the
2283 * checksum of a pseudo header as used by TCP/UDP. It returns the
2286 * For protocols that contain complete checksums such as ICMP/TCP/UDP,
2287 * this function can be used to verify that checksum on received
2288 * packets. In that case the function should return zero if the
2289 * checksum is correct. In particular, this function will return zero
2290 * if skb->ip_summed is CHECKSUM_UNNECESSARY which indicates that the
2291 * hardware has already verified the correctness of the checksum.
2293 static inline __sum16 skb_checksum_complete(struct sk_buff *skb)
2295 return skb_csum_unnecessary(skb) ?
2296 0 : __skb_checksum_complete(skb);
2299 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
2300 extern void nf_conntrack_destroy(struct nf_conntrack *nfct);
2301 static inline void nf_conntrack_put(struct nf_conntrack *nfct)
2303 if (nfct && atomic_dec_and_test(&nfct->use))
2304 nf_conntrack_destroy(nfct);
2306 static inline void nf_conntrack_get(struct nf_conntrack *nfct)
2309 atomic_inc(&nfct->use);
2312 #ifdef NET_SKBUFF_NF_DEFRAG_NEEDED
2313 static inline void nf_conntrack_get_reasm(struct sk_buff *skb)
2316 atomic_inc(&skb->users);
2318 static inline void nf_conntrack_put_reasm(struct sk_buff *skb)
2324 #ifdef CONFIG_BRIDGE_NETFILTER
2325 static inline void nf_bridge_put(struct nf_bridge_info *nf_bridge)
2327 if (nf_bridge && atomic_dec_and_test(&nf_bridge->use))
2330 static inline void nf_bridge_get(struct nf_bridge_info *nf_bridge)
2333 atomic_inc(&nf_bridge->use);
2335 #endif /* CONFIG_BRIDGE_NETFILTER */
2336 static inline void nf_reset(struct sk_buff *skb)
2338 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
2339 nf_conntrack_put(skb->nfct);
2342 #ifdef NET_SKBUFF_NF_DEFRAG_NEEDED
2343 nf_conntrack_put_reasm(skb->nfct_reasm);
2344 skb->nfct_reasm = NULL;
2346 #ifdef CONFIG_BRIDGE_NETFILTER
2347 nf_bridge_put(skb->nf_bridge);
2348 skb->nf_bridge = NULL;
2352 /* Note: This doesn't put any conntrack and bridge info in dst. */
2353 static inline void __nf_copy(struct sk_buff *dst, const struct sk_buff *src)
2355 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
2356 dst->nfct = src->nfct;
2357 nf_conntrack_get(src->nfct);
2358 dst->nfctinfo = src->nfctinfo;
2360 #ifdef NET_SKBUFF_NF_DEFRAG_NEEDED
2361 dst->nfct_reasm = src->nfct_reasm;
2362 nf_conntrack_get_reasm(src->nfct_reasm);
2364 #ifdef CONFIG_BRIDGE_NETFILTER
2365 dst->nf_bridge = src->nf_bridge;
2366 nf_bridge_get(src->nf_bridge);
2370 static inline void nf_copy(struct sk_buff *dst, const struct sk_buff *src)
2372 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
2373 nf_conntrack_put(dst->nfct);
2375 #ifdef NET_SKBUFF_NF_DEFRAG_NEEDED
2376 nf_conntrack_put_reasm(dst->nfct_reasm);
2378 #ifdef CONFIG_BRIDGE_NETFILTER
2379 nf_bridge_put(dst->nf_bridge);
2381 __nf_copy(dst, src);
2384 #ifdef CONFIG_NETWORK_SECMARK
2385 static inline void skb_copy_secmark(struct sk_buff *to, const struct sk_buff *from)
2387 to->secmark = from->secmark;
2390 static inline void skb_init_secmark(struct sk_buff *skb)
2395 static inline void skb_copy_secmark(struct sk_buff *to, const struct sk_buff *from)
2398 static inline void skb_init_secmark(struct sk_buff *skb)
2402 static inline void skb_set_queue_mapping(struct sk_buff *skb, u16 queue_mapping)
2404 skb->queue_mapping = queue_mapping;
2407 static inline u16 skb_get_queue_mapping(const struct sk_buff *skb)
2409 return skb->queue_mapping;
2412 static inline void skb_copy_queue_mapping(struct sk_buff *to, const struct sk_buff *from)
2414 to->queue_mapping = from->queue_mapping;
2417 static inline void skb_record_rx_queue(struct sk_buff *skb, u16 rx_queue)
2419 skb->queue_mapping = rx_queue + 1;
2422 static inline u16 skb_get_rx_queue(const struct sk_buff *skb)
2424 return skb->queue_mapping - 1;
2427 static inline bool skb_rx_queue_recorded(const struct sk_buff *skb)
2429 return skb->queue_mapping != 0;
2432 extern u16 __skb_tx_hash(const struct net_device *dev,
2433 const struct sk_buff *skb,
2434 unsigned int num_tx_queues);
2437 static inline struct sec_path *skb_sec_path(struct sk_buff *skb)
2442 static inline struct sec_path *skb_sec_path(struct sk_buff *skb)
2448 static inline int skb_is_gso(const struct sk_buff *skb)
2450 return skb_shinfo(skb)->gso_size;
2453 static inline int skb_is_gso_v6(const struct sk_buff *skb)
2455 return skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6;
2458 extern void __skb_warn_lro_forwarding(const struct sk_buff *skb);
2460 static inline bool skb_warn_if_lro(const struct sk_buff *skb)
2462 /* LRO sets gso_size but not gso_type, whereas if GSO is really
2463 * wanted then gso_type will be set. */
2464 const struct skb_shared_info *shinfo = skb_shinfo(skb);
2466 if (skb_is_nonlinear(skb) && shinfo->gso_size != 0 &&
2467 unlikely(shinfo->gso_type == 0)) {
2468 __skb_warn_lro_forwarding(skb);
2474 static inline void skb_forward_csum(struct sk_buff *skb)
2476 /* Unfortunately we don't support this one. Any brave souls? */
2477 if (skb->ip_summed == CHECKSUM_COMPLETE)
2478 skb->ip_summed = CHECKSUM_NONE;
2482 * skb_checksum_none_assert - make sure skb ip_summed is CHECKSUM_NONE
2483 * @skb: skb to check
2485 * fresh skbs have their ip_summed set to CHECKSUM_NONE.
2486 * Instead of forcing ip_summed to CHECKSUM_NONE, we can
2487 * use this helper, to document places where we make this assertion.
2489 static inline void skb_checksum_none_assert(const struct sk_buff *skb)
2492 BUG_ON(skb->ip_summed != CHECKSUM_NONE);
2496 bool skb_partial_csum_set(struct sk_buff *skb, u16 start, u16 off);
2498 static inline bool skb_is_recycleable(const struct sk_buff *skb, int skb_size)
2500 if (irqs_disabled())
2503 if (skb_shinfo(skb)->tx_flags & SKBTX_DEV_ZEROCOPY)
2506 if (skb_is_nonlinear(skb) || skb->fclone != SKB_FCLONE_UNAVAILABLE)
2509 skb_size = SKB_DATA_ALIGN(skb_size + NET_SKB_PAD);
2510 if (skb_end_pointer(skb) - skb->head < skb_size)
2513 if (skb_shared(skb) || skb_cloned(skb))
2518 #endif /* __KERNEL__ */
2519 #endif /* _LINUX_SKBUFF_H */