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_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 we
132 * require 64K/PAGE_SIZE pages plus 1 additional page to allow for
133 * buffers which do not start on a page boundary.
135 * Since GRO uses frags we allocate at least 16 regardless of page
138 #if (65536/PAGE_SIZE + 1) < 16
139 #define MAX_SKB_FRAGS 16UL
141 #define MAX_SKB_FRAGS (65536/PAGE_SIZE + 1)
144 typedef struct skb_frag_struct skb_frag_t;
146 struct skb_frag_struct {
150 #if (BITS_PER_LONG > 32) || (PAGE_SIZE >= 65536)
159 static inline unsigned int skb_frag_size(const skb_frag_t *frag)
164 static inline void skb_frag_size_set(skb_frag_t *frag, unsigned int size)
169 static inline void skb_frag_size_add(skb_frag_t *frag, int delta)
174 static inline void skb_frag_size_sub(skb_frag_t *frag, int delta)
179 #define HAVE_HW_TIME_STAMP
182 * struct skb_shared_hwtstamps - hardware time stamps
183 * @hwtstamp: hardware time stamp transformed into duration
184 * since arbitrary point in time
185 * @syststamp: hwtstamp transformed to system time base
187 * Software time stamps generated by ktime_get_real() are stored in
188 * skb->tstamp. The relation between the different kinds of time
189 * stamps is as follows:
191 * syststamp and tstamp can be compared against each other in
192 * arbitrary combinations. The accuracy of a
193 * syststamp/tstamp/"syststamp from other device" comparison is
194 * limited by the accuracy of the transformation into system time
195 * base. This depends on the device driver and its underlying
198 * hwtstamps can only be compared against other hwtstamps from
201 * This structure is attached to packets as part of the
202 * &skb_shared_info. Use skb_hwtstamps() to get a pointer.
204 struct skb_shared_hwtstamps {
209 /* Definitions for tx_flags in struct skb_shared_info */
211 /* generate hardware time stamp */
212 SKBTX_HW_TSTAMP = 1 << 0,
214 /* generate software time stamp */
215 SKBTX_SW_TSTAMP = 1 << 1,
217 /* device driver is going to provide hardware time stamp */
218 SKBTX_IN_PROGRESS = 1 << 2,
220 /* ensure the originating sk reference is available on driver level */
221 SKBTX_DRV_NEEDS_SK_REF = 1 << 3,
223 /* device driver supports TX zero-copy buffers */
224 SKBTX_DEV_ZEROCOPY = 1 << 4,
226 /* generate wifi status information (where possible) */
227 SKBTX_WIFI_STATUS = 1 << 5,
231 * The callback notifies userspace to release buffers when skb DMA is done in
232 * lower device, the skb last reference should be 0 when calling this.
233 * The desc is used to track userspace buffer index.
236 void (*callback)(void *);
241 /* This data is invariant across clones and lives at
242 * the end of the header data, ie. at skb->end.
244 struct skb_shared_info {
245 unsigned char nr_frags;
247 unsigned short gso_size;
248 /* Warning: this field is not always filled in (UFO)! */
249 unsigned short gso_segs;
250 unsigned short gso_type;
251 struct sk_buff *frag_list;
252 struct skb_shared_hwtstamps hwtstamps;
256 * Warning : all fields before dataref are cleared in __alloc_skb()
260 /* Intermediate layers must ensure that destructor_arg
261 * remains valid until skb destructor */
262 void * destructor_arg;
264 /* must be last field, see pskb_expand_head() */
265 skb_frag_t frags[MAX_SKB_FRAGS];
268 /* We divide dataref into two halves. The higher 16 bits hold references
269 * to the payload part of skb->data. The lower 16 bits hold references to
270 * the entire skb->data. A clone of a headerless skb holds the length of
271 * the header in skb->hdr_len.
273 * All users must obey the rule that the skb->data reference count must be
274 * greater than or equal to the payload reference count.
276 * Holding a reference to the payload part means that the user does not
277 * care about modifications to the header part of skb->data.
279 #define SKB_DATAREF_SHIFT 16
280 #define SKB_DATAREF_MASK ((1 << SKB_DATAREF_SHIFT) - 1)
284 SKB_FCLONE_UNAVAILABLE,
290 SKB_GSO_TCPV4 = 1 << 0,
291 SKB_GSO_UDP = 1 << 1,
293 /* This indicates the skb is from an untrusted source. */
294 SKB_GSO_DODGY = 1 << 2,
296 /* This indicates the tcp segment has CWR set. */
297 SKB_GSO_TCP_ECN = 1 << 3,
299 SKB_GSO_TCPV6 = 1 << 4,
301 SKB_GSO_FCOE = 1 << 5,
304 #if BITS_PER_LONG > 32
305 #define NET_SKBUFF_DATA_USES_OFFSET 1
308 #ifdef NET_SKBUFF_DATA_USES_OFFSET
309 typedef unsigned int sk_buff_data_t;
311 typedef unsigned char *sk_buff_data_t;
314 #if defined(CONFIG_NF_DEFRAG_IPV4) || defined(CONFIG_NF_DEFRAG_IPV4_MODULE) || \
315 defined(CONFIG_NF_DEFRAG_IPV6) || defined(CONFIG_NF_DEFRAG_IPV6_MODULE)
316 #define NET_SKBUFF_NF_DEFRAG_NEEDED 1
320 * struct sk_buff - socket buffer
321 * @next: Next buffer in list
322 * @prev: Previous buffer in list
323 * @tstamp: Time we arrived
324 * @sk: Socket we are owned by
325 * @dev: Device we arrived on/are leaving by
326 * @cb: Control buffer. Free for use by every layer. Put private vars here
327 * @_skb_refdst: destination entry (with norefcount bit)
328 * @sp: the security path, used for xfrm
329 * @len: Length of actual data
330 * @data_len: Data length
331 * @mac_len: Length of link layer header
332 * @hdr_len: writable header length of cloned skb
333 * @csum: Checksum (must include start/offset pair)
334 * @csum_start: Offset from skb->head where checksumming should start
335 * @csum_offset: Offset from csum_start where checksum should be stored
336 * @priority: Packet queueing priority
337 * @local_df: allow local fragmentation
338 * @cloned: Head may be cloned (check refcnt to be sure)
339 * @ip_summed: Driver fed us an IP checksum
340 * @nohdr: Payload reference only, must not modify header
341 * @nfctinfo: Relationship of this skb to the connection
342 * @pkt_type: Packet class
343 * @fclone: skbuff clone status
344 * @ipvs_property: skbuff is owned by ipvs
345 * @peeked: this packet has been seen already, so stats have been
346 * done for it, don't do them again
347 * @nf_trace: netfilter packet trace flag
348 * @protocol: Packet protocol from driver
349 * @destructor: Destruct function
350 * @nfct: Associated connection, if any
351 * @nfct_reasm: netfilter conntrack re-assembly pointer
352 * @nf_bridge: Saved data about a bridged frame - see br_netfilter.c
353 * @skb_iif: ifindex of device we arrived on
354 * @tc_index: Traffic control index
355 * @tc_verd: traffic control verdict
356 * @rxhash: the packet hash computed on receive
357 * @queue_mapping: Queue mapping for multiqueue devices
358 * @ndisc_nodetype: router type (from link layer)
359 * @ooo_okay: allow the mapping of a socket to a queue to be changed
360 * @l4_rxhash: indicate rxhash is a canonical 4-tuple hash over transport
362 * @wifi_acked_valid: wifi_acked was set
363 * @wifi_acked: whether frame was acked on wifi or not
364 * @dma_cookie: a cookie to one of several possible DMA operations
365 * done by skb DMA functions
366 * @secmark: security marking
367 * @mark: Generic packet mark
368 * @dropcount: total number of sk_receive_queue overflows
369 * @vlan_tci: vlan tag control information
370 * @transport_header: Transport layer header
371 * @network_header: Network layer header
372 * @mac_header: Link layer header
373 * @tail: Tail pointer
375 * @head: Head of buffer
376 * @data: Data head pointer
377 * @truesize: Buffer size
378 * @users: User count - see {datagram,tcp}.c
382 /* These two members must be first. */
383 struct sk_buff *next;
384 struct sk_buff *prev;
389 struct net_device *dev;
392 * This is the control buffer. It is free to use for every
393 * layer. Please put your private variables there. If you
394 * want to keep them across layers you have to do a skb_clone()
395 * first. This is owned by whoever has the skb queued ATM.
397 char cb[48] __aligned(8);
399 unsigned long _skb_refdst;
415 kmemcheck_bitfield_begin(flags1);
426 kmemcheck_bitfield_end(flags1);
429 void (*destructor)(struct sk_buff *skb);
430 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
431 struct nf_conntrack *nfct;
433 #ifdef NET_SKBUFF_NF_DEFRAG_NEEDED
434 struct sk_buff *nfct_reasm;
436 #ifdef CONFIG_BRIDGE_NETFILTER
437 struct nf_bridge_info *nf_bridge;
446 #ifdef CONFIG_NET_SCHED
447 __u16 tc_index; /* traffic control index */
448 #ifdef CONFIG_NET_CLS_ACT
449 __u16 tc_verd; /* traffic control verdict */
454 kmemcheck_bitfield_begin(flags2);
455 #ifdef CONFIG_IPV6_NDISC_NODETYPE
456 __u8 ndisc_nodetype:2;
460 __u8 wifi_acked_valid:1;
462 /* 10/12 bit hole (depending on ndisc_nodetype presence) */
463 kmemcheck_bitfield_end(flags2);
465 #ifdef CONFIG_NET_DMA
466 dma_cookie_t dma_cookie;
468 #ifdef CONFIG_NETWORK_SECMARK
476 sk_buff_data_t transport_header;
477 sk_buff_data_t network_header;
478 sk_buff_data_t mac_header;
479 /* These elements must be at the end, see alloc_skb() for details. */
484 unsigned int truesize;
490 * Handling routines are only of interest to the kernel
492 #include <linux/slab.h>
494 #include <asm/system.h>
497 * skb might have a dst pointer attached, refcounted or not.
498 * _skb_refdst low order bit is set if refcount was _not_ taken
500 #define SKB_DST_NOREF 1UL
501 #define SKB_DST_PTRMASK ~(SKB_DST_NOREF)
504 * skb_dst - returns skb dst_entry
507 * Returns skb dst_entry, regardless of reference taken or not.
509 static inline struct dst_entry *skb_dst(const struct sk_buff *skb)
511 /* If refdst was not refcounted, check we still are in a
512 * rcu_read_lock section
514 WARN_ON((skb->_skb_refdst & SKB_DST_NOREF) &&
515 !rcu_read_lock_held() &&
516 !rcu_read_lock_bh_held());
517 return (struct dst_entry *)(skb->_skb_refdst & SKB_DST_PTRMASK);
521 * skb_dst_set - sets skb dst
525 * Sets skb dst, assuming a reference was taken on dst and should
526 * be released by skb_dst_drop()
528 static inline void skb_dst_set(struct sk_buff *skb, struct dst_entry *dst)
530 skb->_skb_refdst = (unsigned long)dst;
533 extern void skb_dst_set_noref(struct sk_buff *skb, struct dst_entry *dst);
536 * skb_dst_is_noref - Test if skb dst isn't refcounted
539 static inline bool skb_dst_is_noref(const struct sk_buff *skb)
541 return (skb->_skb_refdst & SKB_DST_NOREF) && skb_dst(skb);
544 static inline struct rtable *skb_rtable(const struct sk_buff *skb)
546 return (struct rtable *)skb_dst(skb);
549 extern void kfree_skb(struct sk_buff *skb);
550 extern void consume_skb(struct sk_buff *skb);
551 extern void __kfree_skb(struct sk_buff *skb);
552 extern struct sk_buff *__alloc_skb(unsigned int size,
553 gfp_t priority, int fclone, int node);
554 extern struct sk_buff *build_skb(void *data);
555 static inline struct sk_buff *alloc_skb(unsigned int size,
558 return __alloc_skb(size, priority, 0, NUMA_NO_NODE);
561 static inline struct sk_buff *alloc_skb_fclone(unsigned int size,
564 return __alloc_skb(size, priority, 1, NUMA_NO_NODE);
567 extern void skb_recycle(struct sk_buff *skb);
568 extern bool skb_recycle_check(struct sk_buff *skb, int skb_size);
570 extern struct sk_buff *skb_morph(struct sk_buff *dst, struct sk_buff *src);
571 extern int skb_copy_ubufs(struct sk_buff *skb, gfp_t gfp_mask);
572 extern struct sk_buff *skb_clone(struct sk_buff *skb,
574 extern struct sk_buff *skb_copy(const struct sk_buff *skb,
576 extern struct sk_buff *__pskb_copy(struct sk_buff *skb,
577 int headroom, gfp_t gfp_mask);
579 extern int pskb_expand_head(struct sk_buff *skb,
580 int nhead, int ntail,
582 extern struct sk_buff *skb_realloc_headroom(struct sk_buff *skb,
583 unsigned int headroom);
584 extern struct sk_buff *skb_copy_expand(const struct sk_buff *skb,
585 int newheadroom, int newtailroom,
587 extern int skb_to_sgvec(struct sk_buff *skb,
588 struct scatterlist *sg, int offset,
590 extern int skb_cow_data(struct sk_buff *skb, int tailbits,
591 struct sk_buff **trailer);
592 extern int skb_pad(struct sk_buff *skb, int pad);
593 #define dev_kfree_skb(a) consume_skb(a)
595 extern int skb_append_datato_frags(struct sock *sk, struct sk_buff *skb,
596 int getfrag(void *from, char *to, int offset,
597 int len,int odd, struct sk_buff *skb),
598 void *from, int length);
600 struct skb_seq_state {
604 __u32 stepped_offset;
605 struct sk_buff *root_skb;
606 struct sk_buff *cur_skb;
610 extern void skb_prepare_seq_read(struct sk_buff *skb,
611 unsigned int from, unsigned int to,
612 struct skb_seq_state *st);
613 extern unsigned int skb_seq_read(unsigned int consumed, const u8 **data,
614 struct skb_seq_state *st);
615 extern void skb_abort_seq_read(struct skb_seq_state *st);
617 extern unsigned int skb_find_text(struct sk_buff *skb, unsigned int from,
618 unsigned int to, struct ts_config *config,
619 struct ts_state *state);
621 extern void __skb_get_rxhash(struct sk_buff *skb);
622 static inline __u32 skb_get_rxhash(struct sk_buff *skb)
625 __skb_get_rxhash(skb);
630 #ifdef NET_SKBUFF_DATA_USES_OFFSET
631 static inline unsigned char *skb_end_pointer(const struct sk_buff *skb)
633 return skb->head + skb->end;
636 static inline unsigned char *skb_end_pointer(const struct sk_buff *skb)
643 #define skb_shinfo(SKB) ((struct skb_shared_info *)(skb_end_pointer(SKB)))
645 static inline struct skb_shared_hwtstamps *skb_hwtstamps(struct sk_buff *skb)
647 return &skb_shinfo(skb)->hwtstamps;
651 * skb_queue_empty - check if a queue is empty
654 * Returns true if the queue is empty, false otherwise.
656 static inline int skb_queue_empty(const struct sk_buff_head *list)
658 return list->next == (struct sk_buff *)list;
662 * skb_queue_is_last - check if skb is the last entry in the queue
666 * Returns true if @skb is the last buffer on the list.
668 static inline bool skb_queue_is_last(const struct sk_buff_head *list,
669 const struct sk_buff *skb)
671 return skb->next == (struct sk_buff *)list;
675 * skb_queue_is_first - check if skb is the first entry in the queue
679 * Returns true if @skb is the first buffer on the list.
681 static inline bool skb_queue_is_first(const struct sk_buff_head *list,
682 const struct sk_buff *skb)
684 return skb->prev == (struct sk_buff *)list;
688 * skb_queue_next - return the next packet in the queue
690 * @skb: current buffer
692 * Return the next packet in @list after @skb. It is only valid to
693 * call this if skb_queue_is_last() evaluates to false.
695 static inline struct sk_buff *skb_queue_next(const struct sk_buff_head *list,
696 const struct sk_buff *skb)
698 /* This BUG_ON may seem severe, but if we just return then we
699 * are going to dereference garbage.
701 BUG_ON(skb_queue_is_last(list, skb));
706 * skb_queue_prev - return the prev packet in the queue
708 * @skb: current buffer
710 * Return the prev packet in @list before @skb. It is only valid to
711 * call this if skb_queue_is_first() evaluates to false.
713 static inline struct sk_buff *skb_queue_prev(const struct sk_buff_head *list,
714 const struct sk_buff *skb)
716 /* This BUG_ON may seem severe, but if we just return then we
717 * are going to dereference garbage.
719 BUG_ON(skb_queue_is_first(list, skb));
724 * skb_get - reference buffer
725 * @skb: buffer to reference
727 * Makes another reference to a socket buffer and returns a pointer
730 static inline struct sk_buff *skb_get(struct sk_buff *skb)
732 atomic_inc(&skb->users);
737 * If users == 1, we are the only owner and are can avoid redundant
742 * skb_cloned - is the buffer a clone
743 * @skb: buffer to check
745 * Returns true if the buffer was generated with skb_clone() and is
746 * one of multiple shared copies of the buffer. Cloned buffers are
747 * shared data so must not be written to under normal circumstances.
749 static inline int skb_cloned(const struct sk_buff *skb)
751 return skb->cloned &&
752 (atomic_read(&skb_shinfo(skb)->dataref) & SKB_DATAREF_MASK) != 1;
756 * skb_header_cloned - is the header a clone
757 * @skb: buffer to check
759 * Returns true if modifying the header part of the buffer requires
760 * the data to be copied.
762 static inline int skb_header_cloned(const struct sk_buff *skb)
769 dataref = atomic_read(&skb_shinfo(skb)->dataref);
770 dataref = (dataref & SKB_DATAREF_MASK) - (dataref >> SKB_DATAREF_SHIFT);
775 * skb_header_release - release reference to header
776 * @skb: buffer to operate on
778 * Drop a reference to the header part of the buffer. This is done
779 * by acquiring a payload reference. You must not read from the header
780 * part of skb->data after this.
782 static inline void skb_header_release(struct sk_buff *skb)
786 atomic_add(1 << SKB_DATAREF_SHIFT, &skb_shinfo(skb)->dataref);
790 * skb_shared - is the buffer shared
791 * @skb: buffer to check
793 * Returns true if more than one person has a reference to this
796 static inline int skb_shared(const struct sk_buff *skb)
798 return atomic_read(&skb->users) != 1;
802 * skb_share_check - check if buffer is shared and if so clone it
803 * @skb: buffer to check
804 * @pri: priority for memory allocation
806 * If the buffer is shared the buffer is cloned and the old copy
807 * drops a reference. A new clone with a single reference is returned.
808 * If the buffer is not shared the original buffer is returned. When
809 * being called from interrupt status or with spinlocks held pri must
812 * NULL is returned on a memory allocation failure.
814 static inline struct sk_buff *skb_share_check(struct sk_buff *skb,
817 might_sleep_if(pri & __GFP_WAIT);
818 if (skb_shared(skb)) {
819 struct sk_buff *nskb = skb_clone(skb, pri);
827 * Copy shared buffers into a new sk_buff. We effectively do COW on
828 * packets to handle cases where we have a local reader and forward
829 * and a couple of other messy ones. The normal one is tcpdumping
830 * a packet thats being forwarded.
834 * skb_unshare - make a copy of a shared buffer
835 * @skb: buffer to check
836 * @pri: priority for memory allocation
838 * If the socket buffer is a clone then this function creates a new
839 * copy of the data, drops a reference count on the old copy and returns
840 * the new copy with the reference count at 1. If the buffer is not a clone
841 * the original buffer is returned. When called with a spinlock held or
842 * from interrupt state @pri must be %GFP_ATOMIC
844 * %NULL is returned on a memory allocation failure.
846 static inline struct sk_buff *skb_unshare(struct sk_buff *skb,
849 might_sleep_if(pri & __GFP_WAIT);
850 if (skb_cloned(skb)) {
851 struct sk_buff *nskb = skb_copy(skb, pri);
852 kfree_skb(skb); /* Free our shared copy */
859 * skb_peek - peek at the head of an &sk_buff_head
860 * @list_: list to peek at
862 * Peek an &sk_buff. Unlike most other operations you _MUST_
863 * be careful with this one. A peek leaves the buffer on the
864 * list and someone else may run off with it. You must hold
865 * the appropriate locks or have a private queue to do this.
867 * Returns %NULL for an empty list or a pointer to the head element.
868 * The reference count is not incremented and the reference is therefore
869 * volatile. Use with caution.
871 static inline struct sk_buff *skb_peek(const struct sk_buff_head *list_)
873 struct sk_buff *list = ((const struct sk_buff *)list_)->next;
874 if (list == (struct sk_buff *)list_)
880 * skb_peek_tail - peek at the tail of an &sk_buff_head
881 * @list_: list to peek at
883 * Peek an &sk_buff. Unlike most other operations you _MUST_
884 * be careful with this one. A peek leaves the buffer on the
885 * list and someone else may run off with it. You must hold
886 * the appropriate locks or have a private queue to do this.
888 * Returns %NULL for an empty list or a pointer to the tail element.
889 * The reference count is not incremented and the reference is therefore
890 * volatile. Use with caution.
892 static inline struct sk_buff *skb_peek_tail(const struct sk_buff_head *list_)
894 struct sk_buff *list = ((const struct sk_buff *)list_)->prev;
895 if (list == (struct sk_buff *)list_)
901 * skb_queue_len - get queue length
902 * @list_: list to measure
904 * Return the length of an &sk_buff queue.
906 static inline __u32 skb_queue_len(const struct sk_buff_head *list_)
912 * __skb_queue_head_init - initialize non-spinlock portions of sk_buff_head
913 * @list: queue to initialize
915 * This initializes only the list and queue length aspects of
916 * an sk_buff_head object. This allows to initialize the list
917 * aspects of an sk_buff_head without reinitializing things like
918 * the spinlock. It can also be used for on-stack sk_buff_head
919 * objects where the spinlock is known to not be used.
921 static inline void __skb_queue_head_init(struct sk_buff_head *list)
923 list->prev = list->next = (struct sk_buff *)list;
928 * This function creates a split out lock class for each invocation;
929 * this is needed for now since a whole lot of users of the skb-queue
930 * infrastructure in drivers have different locking usage (in hardirq)
931 * than the networking core (in softirq only). In the long run either the
932 * network layer or drivers should need annotation to consolidate the
933 * main types of usage into 3 classes.
935 static inline void skb_queue_head_init(struct sk_buff_head *list)
937 spin_lock_init(&list->lock);
938 __skb_queue_head_init(list);
941 static inline void skb_queue_head_init_class(struct sk_buff_head *list,
942 struct lock_class_key *class)
944 skb_queue_head_init(list);
945 lockdep_set_class(&list->lock, class);
949 * Insert an sk_buff on a list.
951 * The "__skb_xxxx()" functions are the non-atomic ones that
952 * can only be called with interrupts disabled.
954 extern void skb_insert(struct sk_buff *old, struct sk_buff *newsk, struct sk_buff_head *list);
955 static inline void __skb_insert(struct sk_buff *newsk,
956 struct sk_buff *prev, struct sk_buff *next,
957 struct sk_buff_head *list)
961 next->prev = prev->next = newsk;
965 static inline void __skb_queue_splice(const struct sk_buff_head *list,
966 struct sk_buff *prev,
967 struct sk_buff *next)
969 struct sk_buff *first = list->next;
970 struct sk_buff *last = list->prev;
980 * skb_queue_splice - join two skb lists, this is designed for stacks
981 * @list: the new list to add
982 * @head: the place to add it in the first list
984 static inline void skb_queue_splice(const struct sk_buff_head *list,
985 struct sk_buff_head *head)
987 if (!skb_queue_empty(list)) {
988 __skb_queue_splice(list, (struct sk_buff *) head, head->next);
989 head->qlen += list->qlen;
994 * skb_queue_splice - join two skb lists and reinitialise the emptied list
995 * @list: the new list to add
996 * @head: the place to add it in the first list
998 * The list at @list is reinitialised
1000 static inline void skb_queue_splice_init(struct sk_buff_head *list,
1001 struct sk_buff_head *head)
1003 if (!skb_queue_empty(list)) {
1004 __skb_queue_splice(list, (struct sk_buff *) head, head->next);
1005 head->qlen += list->qlen;
1006 __skb_queue_head_init(list);
1011 * skb_queue_splice_tail - join two skb lists, each list being a queue
1012 * @list: the new list to add
1013 * @head: the place to add it in the first list
1015 static inline void skb_queue_splice_tail(const struct sk_buff_head *list,
1016 struct sk_buff_head *head)
1018 if (!skb_queue_empty(list)) {
1019 __skb_queue_splice(list, head->prev, (struct sk_buff *) head);
1020 head->qlen += list->qlen;
1025 * skb_queue_splice_tail - join two skb lists and reinitialise the emptied list
1026 * @list: the new list to add
1027 * @head: the place to add it in the first list
1029 * Each of the lists is a queue.
1030 * The list at @list is reinitialised
1032 static inline void skb_queue_splice_tail_init(struct sk_buff_head *list,
1033 struct sk_buff_head *head)
1035 if (!skb_queue_empty(list)) {
1036 __skb_queue_splice(list, head->prev, (struct sk_buff *) head);
1037 head->qlen += list->qlen;
1038 __skb_queue_head_init(list);
1043 * __skb_queue_after - queue a buffer at the list head
1044 * @list: list to use
1045 * @prev: place after this buffer
1046 * @newsk: buffer to queue
1048 * Queue a buffer int the middle of a list. This function takes no locks
1049 * and you must therefore hold required locks before calling it.
1051 * A buffer cannot be placed on two lists at the same time.
1053 static inline void __skb_queue_after(struct sk_buff_head *list,
1054 struct sk_buff *prev,
1055 struct sk_buff *newsk)
1057 __skb_insert(newsk, prev, prev->next, list);
1060 extern void skb_append(struct sk_buff *old, struct sk_buff *newsk,
1061 struct sk_buff_head *list);
1063 static inline void __skb_queue_before(struct sk_buff_head *list,
1064 struct sk_buff *next,
1065 struct sk_buff *newsk)
1067 __skb_insert(newsk, next->prev, next, list);
1071 * __skb_queue_head - queue a buffer at the list head
1072 * @list: list to use
1073 * @newsk: buffer to queue
1075 * Queue a buffer at the start of a list. This function takes no locks
1076 * and you must therefore hold required locks before calling it.
1078 * A buffer cannot be placed on two lists at the same time.
1080 extern void skb_queue_head(struct sk_buff_head *list, struct sk_buff *newsk);
1081 static inline void __skb_queue_head(struct sk_buff_head *list,
1082 struct sk_buff *newsk)
1084 __skb_queue_after(list, (struct sk_buff *)list, newsk);
1088 * __skb_queue_tail - queue a buffer at the list tail
1089 * @list: list to use
1090 * @newsk: buffer to queue
1092 * Queue a buffer at the end of a list. This function takes no locks
1093 * and you must therefore hold required locks before calling it.
1095 * A buffer cannot be placed on two lists at the same time.
1097 extern void skb_queue_tail(struct sk_buff_head *list, struct sk_buff *newsk);
1098 static inline void __skb_queue_tail(struct sk_buff_head *list,
1099 struct sk_buff *newsk)
1101 __skb_queue_before(list, (struct sk_buff *)list, newsk);
1105 * remove sk_buff from list. _Must_ be called atomically, and with
1108 extern void skb_unlink(struct sk_buff *skb, struct sk_buff_head *list);
1109 static inline void __skb_unlink(struct sk_buff *skb, struct sk_buff_head *list)
1111 struct sk_buff *next, *prev;
1116 skb->next = skb->prev = NULL;
1122 * __skb_dequeue - remove from the head of the queue
1123 * @list: list to dequeue from
1125 * Remove the head of the list. This function does not take any locks
1126 * so must be used with appropriate locks held only. The head item is
1127 * returned or %NULL if the list is empty.
1129 extern struct sk_buff *skb_dequeue(struct sk_buff_head *list);
1130 static inline struct sk_buff *__skb_dequeue(struct sk_buff_head *list)
1132 struct sk_buff *skb = skb_peek(list);
1134 __skb_unlink(skb, list);
1139 * __skb_dequeue_tail - remove from the tail of the queue
1140 * @list: list to dequeue from
1142 * Remove the tail of the list. This function does not take any locks
1143 * so must be used with appropriate locks held only. The tail item is
1144 * returned or %NULL if the list is empty.
1146 extern struct sk_buff *skb_dequeue_tail(struct sk_buff_head *list);
1147 static inline struct sk_buff *__skb_dequeue_tail(struct sk_buff_head *list)
1149 struct sk_buff *skb = skb_peek_tail(list);
1151 __skb_unlink(skb, list);
1156 static inline int skb_is_nonlinear(const struct sk_buff *skb)
1158 return skb->data_len;
1161 static inline unsigned int skb_headlen(const struct sk_buff *skb)
1163 return skb->len - skb->data_len;
1166 static inline int skb_pagelen(const struct sk_buff *skb)
1170 for (i = (int)skb_shinfo(skb)->nr_frags - 1; i >= 0; i--)
1171 len += skb_frag_size(&skb_shinfo(skb)->frags[i]);
1172 return len + skb_headlen(skb);
1176 * __skb_fill_page_desc - initialise a paged fragment in an skb
1177 * @skb: buffer containing fragment to be initialised
1178 * @i: paged fragment index to initialise
1179 * @page: the page to use for this fragment
1180 * @off: the offset to the data with @page
1181 * @size: the length of the data
1183 * Initialises the @i'th fragment of @skb to point to &size bytes at
1184 * offset @off within @page.
1186 * Does not take any additional reference on the fragment.
1188 static inline void __skb_fill_page_desc(struct sk_buff *skb, int i,
1189 struct page *page, int off, int size)
1191 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
1193 frag->page.p = page;
1194 frag->page_offset = off;
1195 skb_frag_size_set(frag, size);
1199 * skb_fill_page_desc - initialise a paged fragment in an skb
1200 * @skb: buffer containing fragment to be initialised
1201 * @i: paged fragment index to initialise
1202 * @page: the page to use for this fragment
1203 * @off: the offset to the data with @page
1204 * @size: the length of the data
1206 * As per __skb_fill_page_desc() -- initialises the @i'th fragment of
1207 * @skb to point to &size bytes at offset @off within @page. In
1208 * addition updates @skb such that @i is the last fragment.
1210 * Does not take any additional reference on the fragment.
1212 static inline void skb_fill_page_desc(struct sk_buff *skb, int i,
1213 struct page *page, int off, int size)
1215 __skb_fill_page_desc(skb, i, page, off, size);
1216 skb_shinfo(skb)->nr_frags = i + 1;
1219 extern void skb_add_rx_frag(struct sk_buff *skb, int i, struct page *page,
1222 #define SKB_PAGE_ASSERT(skb) BUG_ON(skb_shinfo(skb)->nr_frags)
1223 #define SKB_FRAG_ASSERT(skb) BUG_ON(skb_has_frag_list(skb))
1224 #define SKB_LINEAR_ASSERT(skb) BUG_ON(skb_is_nonlinear(skb))
1226 #ifdef NET_SKBUFF_DATA_USES_OFFSET
1227 static inline unsigned char *skb_tail_pointer(const struct sk_buff *skb)
1229 return skb->head + skb->tail;
1232 static inline void skb_reset_tail_pointer(struct sk_buff *skb)
1234 skb->tail = skb->data - skb->head;
1237 static inline void skb_set_tail_pointer(struct sk_buff *skb, const int offset)
1239 skb_reset_tail_pointer(skb);
1240 skb->tail += offset;
1242 #else /* NET_SKBUFF_DATA_USES_OFFSET */
1243 static inline unsigned char *skb_tail_pointer(const struct sk_buff *skb)
1248 static inline void skb_reset_tail_pointer(struct sk_buff *skb)
1250 skb->tail = skb->data;
1253 static inline void skb_set_tail_pointer(struct sk_buff *skb, const int offset)
1255 skb->tail = skb->data + offset;
1258 #endif /* NET_SKBUFF_DATA_USES_OFFSET */
1261 * Add data to an sk_buff
1263 extern unsigned char *skb_put(struct sk_buff *skb, unsigned int len);
1264 static inline unsigned char *__skb_put(struct sk_buff *skb, unsigned int len)
1266 unsigned char *tmp = skb_tail_pointer(skb);
1267 SKB_LINEAR_ASSERT(skb);
1273 extern unsigned char *skb_push(struct sk_buff *skb, unsigned int len);
1274 static inline unsigned char *__skb_push(struct sk_buff *skb, unsigned int len)
1281 extern unsigned char *skb_pull(struct sk_buff *skb, unsigned int len);
1282 static inline unsigned char *__skb_pull(struct sk_buff *skb, unsigned int len)
1285 BUG_ON(skb->len < skb->data_len);
1286 return skb->data += len;
1289 static inline unsigned char *skb_pull_inline(struct sk_buff *skb, unsigned int len)
1291 return unlikely(len > skb->len) ? NULL : __skb_pull(skb, len);
1294 extern unsigned char *__pskb_pull_tail(struct sk_buff *skb, int delta);
1296 static inline unsigned char *__pskb_pull(struct sk_buff *skb, unsigned int len)
1298 if (len > skb_headlen(skb) &&
1299 !__pskb_pull_tail(skb, len - skb_headlen(skb)))
1302 return skb->data += len;
1305 static inline unsigned char *pskb_pull(struct sk_buff *skb, unsigned int len)
1307 return unlikely(len > skb->len) ? NULL : __pskb_pull(skb, len);
1310 static inline int pskb_may_pull(struct sk_buff *skb, unsigned int len)
1312 if (likely(len <= skb_headlen(skb)))
1314 if (unlikely(len > skb->len))
1316 return __pskb_pull_tail(skb, len - skb_headlen(skb)) != NULL;
1320 * skb_headroom - bytes at buffer head
1321 * @skb: buffer to check
1323 * Return the number of bytes of free space at the head of an &sk_buff.
1325 static inline unsigned int skb_headroom(const struct sk_buff *skb)
1327 return skb->data - skb->head;
1331 * skb_tailroom - bytes at buffer end
1332 * @skb: buffer to check
1334 * Return the number of bytes of free space at the tail of an sk_buff
1336 static inline int skb_tailroom(const struct sk_buff *skb)
1338 return skb_is_nonlinear(skb) ? 0 : skb->end - skb->tail;
1342 * skb_reserve - adjust headroom
1343 * @skb: buffer to alter
1344 * @len: bytes to move
1346 * Increase the headroom of an empty &sk_buff by reducing the tail
1347 * room. This is only allowed for an empty buffer.
1349 static inline void skb_reserve(struct sk_buff *skb, int len)
1355 static inline void skb_reset_mac_len(struct sk_buff *skb)
1357 skb->mac_len = skb->network_header - skb->mac_header;
1360 #ifdef NET_SKBUFF_DATA_USES_OFFSET
1361 static inline unsigned char *skb_transport_header(const struct sk_buff *skb)
1363 return skb->head + skb->transport_header;
1366 static inline void skb_reset_transport_header(struct sk_buff *skb)
1368 skb->transport_header = skb->data - skb->head;
1371 static inline void skb_set_transport_header(struct sk_buff *skb,
1374 skb_reset_transport_header(skb);
1375 skb->transport_header += offset;
1378 static inline unsigned char *skb_network_header(const struct sk_buff *skb)
1380 return skb->head + skb->network_header;
1383 static inline void skb_reset_network_header(struct sk_buff *skb)
1385 skb->network_header = skb->data - skb->head;
1388 static inline void skb_set_network_header(struct sk_buff *skb, const int offset)
1390 skb_reset_network_header(skb);
1391 skb->network_header += offset;
1394 static inline unsigned char *skb_mac_header(const struct sk_buff *skb)
1396 return skb->head + skb->mac_header;
1399 static inline int skb_mac_header_was_set(const struct sk_buff *skb)
1401 return skb->mac_header != ~0U;
1404 static inline void skb_reset_mac_header(struct sk_buff *skb)
1406 skb->mac_header = skb->data - skb->head;
1409 static inline void skb_set_mac_header(struct sk_buff *skb, const int offset)
1411 skb_reset_mac_header(skb);
1412 skb->mac_header += offset;
1415 #else /* NET_SKBUFF_DATA_USES_OFFSET */
1417 static inline unsigned char *skb_transport_header(const struct sk_buff *skb)
1419 return skb->transport_header;
1422 static inline void skb_reset_transport_header(struct sk_buff *skb)
1424 skb->transport_header = skb->data;
1427 static inline void skb_set_transport_header(struct sk_buff *skb,
1430 skb->transport_header = skb->data + offset;
1433 static inline unsigned char *skb_network_header(const struct sk_buff *skb)
1435 return skb->network_header;
1438 static inline void skb_reset_network_header(struct sk_buff *skb)
1440 skb->network_header = skb->data;
1443 static inline void skb_set_network_header(struct sk_buff *skb, const int offset)
1445 skb->network_header = skb->data + offset;
1448 static inline unsigned char *skb_mac_header(const struct sk_buff *skb)
1450 return skb->mac_header;
1453 static inline int skb_mac_header_was_set(const struct sk_buff *skb)
1455 return skb->mac_header != NULL;
1458 static inline void skb_reset_mac_header(struct sk_buff *skb)
1460 skb->mac_header = skb->data;
1463 static inline void skb_set_mac_header(struct sk_buff *skb, const int offset)
1465 skb->mac_header = skb->data + offset;
1467 #endif /* NET_SKBUFF_DATA_USES_OFFSET */
1469 static inline int skb_checksum_start_offset(const struct sk_buff *skb)
1471 return skb->csum_start - skb_headroom(skb);
1474 static inline int skb_transport_offset(const struct sk_buff *skb)
1476 return skb_transport_header(skb) - skb->data;
1479 static inline u32 skb_network_header_len(const struct sk_buff *skb)
1481 return skb->transport_header - skb->network_header;
1484 static inline int skb_network_offset(const struct sk_buff *skb)
1486 return skb_network_header(skb) - skb->data;
1489 static inline int pskb_network_may_pull(struct sk_buff *skb, unsigned int len)
1491 return pskb_may_pull(skb, skb_network_offset(skb) + len);
1495 * CPUs often take a performance hit when accessing unaligned memory
1496 * locations. The actual performance hit varies, it can be small if the
1497 * hardware handles it or large if we have to take an exception and fix it
1500 * Since an ethernet header is 14 bytes network drivers often end up with
1501 * the IP header at an unaligned offset. The IP header can be aligned by
1502 * shifting the start of the packet by 2 bytes. Drivers should do this
1505 * skb_reserve(skb, NET_IP_ALIGN);
1507 * The downside to this alignment of the IP header is that the DMA is now
1508 * unaligned. On some architectures the cost of an unaligned DMA is high
1509 * and this cost outweighs the gains made by aligning the IP header.
1511 * Since this trade off varies between architectures, we allow NET_IP_ALIGN
1514 #ifndef NET_IP_ALIGN
1515 #define NET_IP_ALIGN 2
1519 * The networking layer reserves some headroom in skb data (via
1520 * dev_alloc_skb). This is used to avoid having to reallocate skb data when
1521 * the header has to grow. In the default case, if the header has to grow
1522 * 32 bytes or less we avoid the reallocation.
1524 * Unfortunately this headroom changes the DMA alignment of the resulting
1525 * network packet. As for NET_IP_ALIGN, this unaligned DMA is expensive
1526 * on some architectures. An architecture can override this value,
1527 * perhaps setting it to a cacheline in size (since that will maintain
1528 * cacheline alignment of the DMA). It must be a power of 2.
1530 * Various parts of the networking layer expect at least 32 bytes of
1531 * headroom, you should not reduce this.
1533 * Using max(32, L1_CACHE_BYTES) makes sense (especially with RPS)
1534 * to reduce average number of cache lines per packet.
1535 * get_rps_cpus() for example only access one 64 bytes aligned block :
1536 * NET_IP_ALIGN(2) + ethernet_header(14) + IP_header(20/40) + ports(8)
1539 #define NET_SKB_PAD max(32, L1_CACHE_BYTES)
1542 extern int ___pskb_trim(struct sk_buff *skb, unsigned int len);
1544 static inline void __skb_trim(struct sk_buff *skb, unsigned int len)
1546 if (unlikely(skb_is_nonlinear(skb))) {
1551 skb_set_tail_pointer(skb, len);
1554 extern void skb_trim(struct sk_buff *skb, unsigned int len);
1556 static inline int __pskb_trim(struct sk_buff *skb, unsigned int len)
1559 return ___pskb_trim(skb, len);
1560 __skb_trim(skb, len);
1564 static inline int pskb_trim(struct sk_buff *skb, unsigned int len)
1566 return (len < skb->len) ? __pskb_trim(skb, len) : 0;
1570 * pskb_trim_unique - remove end from a paged unique (not cloned) buffer
1571 * @skb: buffer to alter
1574 * This is identical to pskb_trim except that the caller knows that
1575 * the skb is not cloned so we should never get an error due to out-
1578 static inline void pskb_trim_unique(struct sk_buff *skb, unsigned int len)
1580 int err = pskb_trim(skb, len);
1585 * skb_orphan - orphan a buffer
1586 * @skb: buffer to orphan
1588 * If a buffer currently has an owner then we call the owner's
1589 * destructor function and make the @skb unowned. The buffer continues
1590 * to exist but is no longer charged to its former owner.
1592 static inline void skb_orphan(struct sk_buff *skb)
1594 if (skb->destructor)
1595 skb->destructor(skb);
1596 skb->destructor = NULL;
1601 * __skb_queue_purge - empty a list
1602 * @list: list to empty
1604 * Delete all buffers on an &sk_buff list. Each buffer is removed from
1605 * the list and one reference dropped. This function does not take the
1606 * list lock and the caller must hold the relevant locks to use it.
1608 extern void skb_queue_purge(struct sk_buff_head *list);
1609 static inline void __skb_queue_purge(struct sk_buff_head *list)
1611 struct sk_buff *skb;
1612 while ((skb = __skb_dequeue(list)) != NULL)
1617 * __dev_alloc_skb - allocate an skbuff for receiving
1618 * @length: length to allocate
1619 * @gfp_mask: get_free_pages mask, passed to alloc_skb
1621 * Allocate a new &sk_buff and assign it a usage count of one. The
1622 * buffer has unspecified headroom built in. Users should allocate
1623 * the headroom they think they need without accounting for the
1624 * built in space. The built in space is used for optimisations.
1626 * %NULL is returned if there is no free memory.
1628 static inline struct sk_buff *__dev_alloc_skb(unsigned int length,
1631 struct sk_buff *skb = alloc_skb(length + NET_SKB_PAD, gfp_mask);
1633 skb_reserve(skb, NET_SKB_PAD);
1637 extern struct sk_buff *dev_alloc_skb(unsigned int length);
1639 extern struct sk_buff *__netdev_alloc_skb(struct net_device *dev,
1640 unsigned int length, gfp_t gfp_mask);
1643 * netdev_alloc_skb - allocate an skbuff for rx on a specific device
1644 * @dev: network device to receive on
1645 * @length: length to allocate
1647 * Allocate a new &sk_buff and assign it a usage count of one. The
1648 * buffer has unspecified headroom built in. Users should allocate
1649 * the headroom they think they need without accounting for the
1650 * built in space. The built in space is used for optimisations.
1652 * %NULL is returned if there is no free memory. Although this function
1653 * allocates memory it can be called from an interrupt.
1655 static inline struct sk_buff *netdev_alloc_skb(struct net_device *dev,
1656 unsigned int length)
1658 return __netdev_alloc_skb(dev, length, GFP_ATOMIC);
1661 static inline struct sk_buff *__netdev_alloc_skb_ip_align(struct net_device *dev,
1662 unsigned int length, gfp_t gfp)
1664 struct sk_buff *skb = __netdev_alloc_skb(dev, length + NET_IP_ALIGN, gfp);
1666 if (NET_IP_ALIGN && skb)
1667 skb_reserve(skb, NET_IP_ALIGN);
1671 static inline struct sk_buff *netdev_alloc_skb_ip_align(struct net_device *dev,
1672 unsigned int length)
1674 return __netdev_alloc_skb_ip_align(dev, length, GFP_ATOMIC);
1678 * skb_frag_page - retrieve the page refered to by a paged fragment
1679 * @frag: the paged fragment
1681 * Returns the &struct page associated with @frag.
1683 static inline struct page *skb_frag_page(const skb_frag_t *frag)
1685 return frag->page.p;
1689 * __skb_frag_ref - take an addition reference on a paged fragment.
1690 * @frag: the paged fragment
1692 * Takes an additional reference on the paged fragment @frag.
1694 static inline void __skb_frag_ref(skb_frag_t *frag)
1696 get_page(skb_frag_page(frag));
1700 * skb_frag_ref - take an addition reference on a paged fragment of an skb.
1702 * @f: the fragment offset.
1704 * Takes an additional reference on the @f'th paged fragment of @skb.
1706 static inline void skb_frag_ref(struct sk_buff *skb, int f)
1708 __skb_frag_ref(&skb_shinfo(skb)->frags[f]);
1712 * __skb_frag_unref - release a reference on a paged fragment.
1713 * @frag: the paged fragment
1715 * Releases a reference on the paged fragment @frag.
1717 static inline void __skb_frag_unref(skb_frag_t *frag)
1719 put_page(skb_frag_page(frag));
1723 * skb_frag_unref - release a reference on a paged fragment of an skb.
1725 * @f: the fragment offset
1727 * Releases a reference on the @f'th paged fragment of @skb.
1729 static inline void skb_frag_unref(struct sk_buff *skb, int f)
1731 __skb_frag_unref(&skb_shinfo(skb)->frags[f]);
1735 * skb_frag_address - gets the address of the data contained in a paged fragment
1736 * @frag: the paged fragment buffer
1738 * Returns the address of the data within @frag. The page must already
1741 static inline void *skb_frag_address(const skb_frag_t *frag)
1743 return page_address(skb_frag_page(frag)) + frag->page_offset;
1747 * skb_frag_address_safe - gets the address of the data contained in a paged fragment
1748 * @frag: the paged fragment buffer
1750 * Returns the address of the data within @frag. Checks that the page
1751 * is mapped and returns %NULL otherwise.
1753 static inline void *skb_frag_address_safe(const skb_frag_t *frag)
1755 void *ptr = page_address(skb_frag_page(frag));
1759 return ptr + frag->page_offset;
1763 * __skb_frag_set_page - sets the page contained in a paged fragment
1764 * @frag: the paged fragment
1765 * @page: the page to set
1767 * Sets the fragment @frag to contain @page.
1769 static inline void __skb_frag_set_page(skb_frag_t *frag, struct page *page)
1771 frag->page.p = page;
1775 * skb_frag_set_page - sets the page contained in a paged fragment of an skb
1777 * @f: the fragment offset
1778 * @page: the page to set
1780 * Sets the @f'th fragment of @skb to contain @page.
1782 static inline void skb_frag_set_page(struct sk_buff *skb, int f,
1785 __skb_frag_set_page(&skb_shinfo(skb)->frags[f], page);
1789 * skb_frag_dma_map - maps a paged fragment via the DMA API
1790 * @dev: the device to map the fragment to
1791 * @frag: the paged fragment to map
1792 * @offset: the offset within the fragment (starting at the
1793 * fragment's own offset)
1794 * @size: the number of bytes to map
1795 * @dir: the direction of the mapping (%PCI_DMA_*)
1797 * Maps the page associated with @frag to @device.
1799 static inline dma_addr_t skb_frag_dma_map(struct device *dev,
1800 const skb_frag_t *frag,
1801 size_t offset, size_t size,
1802 enum dma_data_direction dir)
1804 return dma_map_page(dev, skb_frag_page(frag),
1805 frag->page_offset + offset, size, dir);
1808 static inline struct sk_buff *pskb_copy(struct sk_buff *skb,
1811 return __pskb_copy(skb, skb_headroom(skb), gfp_mask);
1815 * skb_clone_writable - is the header of a clone writable
1816 * @skb: buffer to check
1817 * @len: length up to which to write
1819 * Returns true if modifying the header part of the cloned buffer
1820 * does not requires the data to be copied.
1822 static inline int skb_clone_writable(const struct sk_buff *skb, unsigned int len)
1824 return !skb_header_cloned(skb) &&
1825 skb_headroom(skb) + len <= skb->hdr_len;
1828 static inline int __skb_cow(struct sk_buff *skb, unsigned int headroom,
1833 if (headroom < NET_SKB_PAD)
1834 headroom = NET_SKB_PAD;
1835 if (headroom > skb_headroom(skb))
1836 delta = headroom - skb_headroom(skb);
1838 if (delta || cloned)
1839 return pskb_expand_head(skb, ALIGN(delta, NET_SKB_PAD), 0,
1845 * skb_cow - copy header of skb when it is required
1846 * @skb: buffer to cow
1847 * @headroom: needed headroom
1849 * If the skb passed lacks sufficient headroom or its data part
1850 * is shared, data is reallocated. If reallocation fails, an error
1851 * is returned and original skb is not changed.
1853 * The result is skb with writable area skb->head...skb->tail
1854 * and at least @headroom of space at head.
1856 static inline int skb_cow(struct sk_buff *skb, unsigned int headroom)
1858 return __skb_cow(skb, headroom, skb_cloned(skb));
1862 * skb_cow_head - skb_cow but only making the head writable
1863 * @skb: buffer to cow
1864 * @headroom: needed headroom
1866 * This function is identical to skb_cow except that we replace the
1867 * skb_cloned check by skb_header_cloned. It should be used when
1868 * you only need to push on some header and do not need to modify
1871 static inline int skb_cow_head(struct sk_buff *skb, unsigned int headroom)
1873 return __skb_cow(skb, headroom, skb_header_cloned(skb));
1877 * skb_padto - pad an skbuff up to a minimal size
1878 * @skb: buffer to pad
1879 * @len: minimal length
1881 * Pads up a buffer to ensure the trailing bytes exist and are
1882 * blanked. If the buffer already contains sufficient data it
1883 * is untouched. Otherwise it is extended. Returns zero on
1884 * success. The skb is freed on error.
1887 static inline int skb_padto(struct sk_buff *skb, unsigned int len)
1889 unsigned int size = skb->len;
1890 if (likely(size >= len))
1892 return skb_pad(skb, len - size);
1895 static inline int skb_add_data(struct sk_buff *skb,
1896 char __user *from, int copy)
1898 const int off = skb->len;
1900 if (skb->ip_summed == CHECKSUM_NONE) {
1902 __wsum csum = csum_and_copy_from_user(from, skb_put(skb, copy),
1905 skb->csum = csum_block_add(skb->csum, csum, off);
1908 } else if (!copy_from_user(skb_put(skb, copy), from, copy))
1911 __skb_trim(skb, off);
1915 static inline int skb_can_coalesce(struct sk_buff *skb, int i,
1916 const struct page *page, int off)
1919 const struct skb_frag_struct *frag = &skb_shinfo(skb)->frags[i - 1];
1921 return page == skb_frag_page(frag) &&
1922 off == frag->page_offset + skb_frag_size(frag);
1927 static inline int __skb_linearize(struct sk_buff *skb)
1929 return __pskb_pull_tail(skb, skb->data_len) ? 0 : -ENOMEM;
1933 * skb_linearize - convert paged skb to linear one
1934 * @skb: buffer to linarize
1936 * If there is no free memory -ENOMEM is returned, otherwise zero
1937 * is returned and the old skb data released.
1939 static inline int skb_linearize(struct sk_buff *skb)
1941 return skb_is_nonlinear(skb) ? __skb_linearize(skb) : 0;
1945 * skb_linearize_cow - make sure skb is linear and writable
1946 * @skb: buffer to process
1948 * If there is no free memory -ENOMEM is returned, otherwise zero
1949 * is returned and the old skb data released.
1951 static inline int skb_linearize_cow(struct sk_buff *skb)
1953 return skb_is_nonlinear(skb) || skb_cloned(skb) ?
1954 __skb_linearize(skb) : 0;
1958 * skb_postpull_rcsum - update checksum for received skb after pull
1959 * @skb: buffer to update
1960 * @start: start of data before pull
1961 * @len: length of data pulled
1963 * After doing a pull on a received packet, you need to call this to
1964 * update the CHECKSUM_COMPLETE checksum, or set ip_summed to
1965 * CHECKSUM_NONE so that it can be recomputed from scratch.
1968 static inline void skb_postpull_rcsum(struct sk_buff *skb,
1969 const void *start, unsigned int len)
1971 if (skb->ip_summed == CHECKSUM_COMPLETE)
1972 skb->csum = csum_sub(skb->csum, csum_partial(start, len, 0));
1975 unsigned char *skb_pull_rcsum(struct sk_buff *skb, unsigned int len);
1978 * pskb_trim_rcsum - trim received skb and update checksum
1979 * @skb: buffer to trim
1982 * This is exactly the same as pskb_trim except that it ensures the
1983 * checksum of received packets are still valid after the operation.
1986 static inline int pskb_trim_rcsum(struct sk_buff *skb, unsigned int len)
1988 if (likely(len >= skb->len))
1990 if (skb->ip_summed == CHECKSUM_COMPLETE)
1991 skb->ip_summed = CHECKSUM_NONE;
1992 return __pskb_trim(skb, len);
1995 #define skb_queue_walk(queue, skb) \
1996 for (skb = (queue)->next; \
1997 skb != (struct sk_buff *)(queue); \
2000 #define skb_queue_walk_safe(queue, skb, tmp) \
2001 for (skb = (queue)->next, tmp = skb->next; \
2002 skb != (struct sk_buff *)(queue); \
2003 skb = tmp, tmp = skb->next)
2005 #define skb_queue_walk_from(queue, skb) \
2006 for (; skb != (struct sk_buff *)(queue); \
2009 #define skb_queue_walk_from_safe(queue, skb, tmp) \
2010 for (tmp = skb->next; \
2011 skb != (struct sk_buff *)(queue); \
2012 skb = tmp, tmp = skb->next)
2014 #define skb_queue_reverse_walk(queue, skb) \
2015 for (skb = (queue)->prev; \
2016 skb != (struct sk_buff *)(queue); \
2019 #define skb_queue_reverse_walk_safe(queue, skb, tmp) \
2020 for (skb = (queue)->prev, tmp = skb->prev; \
2021 skb != (struct sk_buff *)(queue); \
2022 skb = tmp, tmp = skb->prev)
2024 #define skb_queue_reverse_walk_from_safe(queue, skb, tmp) \
2025 for (tmp = skb->prev; \
2026 skb != (struct sk_buff *)(queue); \
2027 skb = tmp, tmp = skb->prev)
2029 static inline bool skb_has_frag_list(const struct sk_buff *skb)
2031 return skb_shinfo(skb)->frag_list != NULL;
2034 static inline void skb_frag_list_init(struct sk_buff *skb)
2036 skb_shinfo(skb)->frag_list = NULL;
2039 static inline void skb_frag_add_head(struct sk_buff *skb, struct sk_buff *frag)
2041 frag->next = skb_shinfo(skb)->frag_list;
2042 skb_shinfo(skb)->frag_list = frag;
2045 #define skb_walk_frags(skb, iter) \
2046 for (iter = skb_shinfo(skb)->frag_list; iter; iter = iter->next)
2048 extern struct sk_buff *__skb_recv_datagram(struct sock *sk, unsigned flags,
2049 int *peeked, int *err);
2050 extern struct sk_buff *skb_recv_datagram(struct sock *sk, unsigned flags,
2051 int noblock, int *err);
2052 extern unsigned int datagram_poll(struct file *file, struct socket *sock,
2053 struct poll_table_struct *wait);
2054 extern int skb_copy_datagram_iovec(const struct sk_buff *from,
2055 int offset, struct iovec *to,
2057 extern int skb_copy_and_csum_datagram_iovec(struct sk_buff *skb,
2060 extern int skb_copy_datagram_from_iovec(struct sk_buff *skb,
2062 const struct iovec *from,
2065 extern int skb_copy_datagram_const_iovec(const struct sk_buff *from,
2067 const struct iovec *to,
2070 extern void skb_free_datagram(struct sock *sk, struct sk_buff *skb);
2071 extern void skb_free_datagram_locked(struct sock *sk,
2072 struct sk_buff *skb);
2073 extern int skb_kill_datagram(struct sock *sk, struct sk_buff *skb,
2074 unsigned int flags);
2075 extern __wsum skb_checksum(const struct sk_buff *skb, int offset,
2076 int len, __wsum csum);
2077 extern int skb_copy_bits(const struct sk_buff *skb, int offset,
2079 extern int skb_store_bits(struct sk_buff *skb, int offset,
2080 const void *from, int len);
2081 extern __wsum skb_copy_and_csum_bits(const struct sk_buff *skb,
2082 int offset, u8 *to, int len,
2084 extern int skb_splice_bits(struct sk_buff *skb,
2085 unsigned int offset,
2086 struct pipe_inode_info *pipe,
2088 unsigned int flags);
2089 extern void skb_copy_and_csum_dev(const struct sk_buff *skb, u8 *to);
2090 extern void skb_split(struct sk_buff *skb,
2091 struct sk_buff *skb1, const u32 len);
2092 extern int skb_shift(struct sk_buff *tgt, struct sk_buff *skb,
2095 extern struct sk_buff *skb_segment(struct sk_buff *skb,
2096 netdev_features_t features);
2098 static inline void *skb_header_pointer(const struct sk_buff *skb, int offset,
2099 int len, void *buffer)
2101 int hlen = skb_headlen(skb);
2103 if (hlen - offset >= len)
2104 return skb->data + offset;
2106 if (skb_copy_bits(skb, offset, buffer, len) < 0)
2112 static inline void skb_copy_from_linear_data(const struct sk_buff *skb,
2114 const unsigned int len)
2116 memcpy(to, skb->data, len);
2119 static inline void skb_copy_from_linear_data_offset(const struct sk_buff *skb,
2120 const int offset, void *to,
2121 const unsigned int len)
2123 memcpy(to, skb->data + offset, len);
2126 static inline void skb_copy_to_linear_data(struct sk_buff *skb,
2128 const unsigned int len)
2130 memcpy(skb->data, from, len);
2133 static inline void skb_copy_to_linear_data_offset(struct sk_buff *skb,
2136 const unsigned int len)
2138 memcpy(skb->data + offset, from, len);
2141 extern void skb_init(void);
2143 static inline ktime_t skb_get_ktime(const struct sk_buff *skb)
2149 * skb_get_timestamp - get timestamp from a skb
2150 * @skb: skb to get stamp from
2151 * @stamp: pointer to struct timeval to store stamp in
2153 * Timestamps are stored in the skb as offsets to a base timestamp.
2154 * This function converts the offset back to a struct timeval and stores
2157 static inline void skb_get_timestamp(const struct sk_buff *skb,
2158 struct timeval *stamp)
2160 *stamp = ktime_to_timeval(skb->tstamp);
2163 static inline void skb_get_timestampns(const struct sk_buff *skb,
2164 struct timespec *stamp)
2166 *stamp = ktime_to_timespec(skb->tstamp);
2169 static inline void __net_timestamp(struct sk_buff *skb)
2171 skb->tstamp = ktime_get_real();
2174 static inline ktime_t net_timedelta(ktime_t t)
2176 return ktime_sub(ktime_get_real(), t);
2179 static inline ktime_t net_invalid_timestamp(void)
2181 return ktime_set(0, 0);
2184 extern void skb_timestamping_init(void);
2186 #ifdef CONFIG_NETWORK_PHY_TIMESTAMPING
2188 extern void skb_clone_tx_timestamp(struct sk_buff *skb);
2189 extern bool skb_defer_rx_timestamp(struct sk_buff *skb);
2191 #else /* CONFIG_NETWORK_PHY_TIMESTAMPING */
2193 static inline void skb_clone_tx_timestamp(struct sk_buff *skb)
2197 static inline bool skb_defer_rx_timestamp(struct sk_buff *skb)
2202 #endif /* !CONFIG_NETWORK_PHY_TIMESTAMPING */
2205 * skb_complete_tx_timestamp() - deliver cloned skb with tx timestamps
2207 * PHY drivers may accept clones of transmitted packets for
2208 * timestamping via their phy_driver.txtstamp method. These drivers
2209 * must call this function to return the skb back to the stack, with
2210 * or without a timestamp.
2212 * @skb: clone of the the original outgoing packet
2213 * @hwtstamps: hardware time stamps, may be NULL if not available
2216 void skb_complete_tx_timestamp(struct sk_buff *skb,
2217 struct skb_shared_hwtstamps *hwtstamps);
2220 * skb_tstamp_tx - queue clone of skb with send time stamps
2221 * @orig_skb: the original outgoing packet
2222 * @hwtstamps: hardware time stamps, may be NULL if not available
2224 * If the skb has a socket associated, then this function clones the
2225 * skb (thus sharing the actual data and optional structures), stores
2226 * the optional hardware time stamping information (if non NULL) or
2227 * generates a software time stamp (otherwise), then queues the clone
2228 * to the error queue of the socket. Errors are silently ignored.
2230 extern void skb_tstamp_tx(struct sk_buff *orig_skb,
2231 struct skb_shared_hwtstamps *hwtstamps);
2233 static inline void sw_tx_timestamp(struct sk_buff *skb)
2235 if (skb_shinfo(skb)->tx_flags & SKBTX_SW_TSTAMP &&
2236 !(skb_shinfo(skb)->tx_flags & SKBTX_IN_PROGRESS))
2237 skb_tstamp_tx(skb, NULL);
2241 * skb_tx_timestamp() - Driver hook for transmit timestamping
2243 * Ethernet MAC Drivers should call this function in their hard_xmit()
2244 * function immediately before giving the sk_buff to the MAC hardware.
2246 * @skb: A socket buffer.
2248 static inline void skb_tx_timestamp(struct sk_buff *skb)
2250 skb_clone_tx_timestamp(skb);
2251 sw_tx_timestamp(skb);
2255 * skb_complete_wifi_ack - deliver skb with wifi status
2257 * @skb: the original outgoing packet
2258 * @acked: ack status
2261 void skb_complete_wifi_ack(struct sk_buff *skb, bool acked);
2263 extern __sum16 __skb_checksum_complete_head(struct sk_buff *skb, int len);
2264 extern __sum16 __skb_checksum_complete(struct sk_buff *skb);
2266 static inline int skb_csum_unnecessary(const struct sk_buff *skb)
2268 return skb->ip_summed & CHECKSUM_UNNECESSARY;
2272 * skb_checksum_complete - Calculate checksum of an entire packet
2273 * @skb: packet to process
2275 * This function calculates the checksum over the entire packet plus
2276 * the value of skb->csum. The latter can be used to supply the
2277 * checksum of a pseudo header as used by TCP/UDP. It returns the
2280 * For protocols that contain complete checksums such as ICMP/TCP/UDP,
2281 * this function can be used to verify that checksum on received
2282 * packets. In that case the function should return zero if the
2283 * checksum is correct. In particular, this function will return zero
2284 * if skb->ip_summed is CHECKSUM_UNNECESSARY which indicates that the
2285 * hardware has already verified the correctness of the checksum.
2287 static inline __sum16 skb_checksum_complete(struct sk_buff *skb)
2289 return skb_csum_unnecessary(skb) ?
2290 0 : __skb_checksum_complete(skb);
2293 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
2294 extern void nf_conntrack_destroy(struct nf_conntrack *nfct);
2295 static inline void nf_conntrack_put(struct nf_conntrack *nfct)
2297 if (nfct && atomic_dec_and_test(&nfct->use))
2298 nf_conntrack_destroy(nfct);
2300 static inline void nf_conntrack_get(struct nf_conntrack *nfct)
2303 atomic_inc(&nfct->use);
2306 #ifdef NET_SKBUFF_NF_DEFRAG_NEEDED
2307 static inline void nf_conntrack_get_reasm(struct sk_buff *skb)
2310 atomic_inc(&skb->users);
2312 static inline void nf_conntrack_put_reasm(struct sk_buff *skb)
2318 #ifdef CONFIG_BRIDGE_NETFILTER
2319 static inline void nf_bridge_put(struct nf_bridge_info *nf_bridge)
2321 if (nf_bridge && atomic_dec_and_test(&nf_bridge->use))
2324 static inline void nf_bridge_get(struct nf_bridge_info *nf_bridge)
2327 atomic_inc(&nf_bridge->use);
2329 #endif /* CONFIG_BRIDGE_NETFILTER */
2330 static inline void nf_reset(struct sk_buff *skb)
2332 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
2333 nf_conntrack_put(skb->nfct);
2336 #ifdef NET_SKBUFF_NF_DEFRAG_NEEDED
2337 nf_conntrack_put_reasm(skb->nfct_reasm);
2338 skb->nfct_reasm = NULL;
2340 #ifdef CONFIG_BRIDGE_NETFILTER
2341 nf_bridge_put(skb->nf_bridge);
2342 skb->nf_bridge = NULL;
2346 /* Note: This doesn't put any conntrack and bridge info in dst. */
2347 static inline void __nf_copy(struct sk_buff *dst, const struct sk_buff *src)
2349 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
2350 dst->nfct = src->nfct;
2351 nf_conntrack_get(src->nfct);
2352 dst->nfctinfo = src->nfctinfo;
2354 #ifdef NET_SKBUFF_NF_DEFRAG_NEEDED
2355 dst->nfct_reasm = src->nfct_reasm;
2356 nf_conntrack_get_reasm(src->nfct_reasm);
2358 #ifdef CONFIG_BRIDGE_NETFILTER
2359 dst->nf_bridge = src->nf_bridge;
2360 nf_bridge_get(src->nf_bridge);
2364 static inline void nf_copy(struct sk_buff *dst, const struct sk_buff *src)
2366 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
2367 nf_conntrack_put(dst->nfct);
2369 #ifdef NET_SKBUFF_NF_DEFRAG_NEEDED
2370 nf_conntrack_put_reasm(dst->nfct_reasm);
2372 #ifdef CONFIG_BRIDGE_NETFILTER
2373 nf_bridge_put(dst->nf_bridge);
2375 __nf_copy(dst, src);
2378 #ifdef CONFIG_NETWORK_SECMARK
2379 static inline void skb_copy_secmark(struct sk_buff *to, const struct sk_buff *from)
2381 to->secmark = from->secmark;
2384 static inline void skb_init_secmark(struct sk_buff *skb)
2389 static inline void skb_copy_secmark(struct sk_buff *to, const struct sk_buff *from)
2392 static inline void skb_init_secmark(struct sk_buff *skb)
2396 static inline void skb_set_queue_mapping(struct sk_buff *skb, u16 queue_mapping)
2398 skb->queue_mapping = queue_mapping;
2401 static inline u16 skb_get_queue_mapping(const struct sk_buff *skb)
2403 return skb->queue_mapping;
2406 static inline void skb_copy_queue_mapping(struct sk_buff *to, const struct sk_buff *from)
2408 to->queue_mapping = from->queue_mapping;
2411 static inline void skb_record_rx_queue(struct sk_buff *skb, u16 rx_queue)
2413 skb->queue_mapping = rx_queue + 1;
2416 static inline u16 skb_get_rx_queue(const struct sk_buff *skb)
2418 return skb->queue_mapping - 1;
2421 static inline bool skb_rx_queue_recorded(const struct sk_buff *skb)
2423 return skb->queue_mapping != 0;
2426 extern u16 __skb_tx_hash(const struct net_device *dev,
2427 const struct sk_buff *skb,
2428 unsigned int num_tx_queues);
2431 static inline struct sec_path *skb_sec_path(struct sk_buff *skb)
2436 static inline struct sec_path *skb_sec_path(struct sk_buff *skb)
2442 static inline int skb_is_gso(const struct sk_buff *skb)
2444 return skb_shinfo(skb)->gso_size;
2447 static inline int skb_is_gso_v6(const struct sk_buff *skb)
2449 return skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6;
2452 extern void __skb_warn_lro_forwarding(const struct sk_buff *skb);
2454 static inline bool skb_warn_if_lro(const struct sk_buff *skb)
2456 /* LRO sets gso_size but not gso_type, whereas if GSO is really
2457 * wanted then gso_type will be set. */
2458 const struct skb_shared_info *shinfo = skb_shinfo(skb);
2460 if (skb_is_nonlinear(skb) && shinfo->gso_size != 0 &&
2461 unlikely(shinfo->gso_type == 0)) {
2462 __skb_warn_lro_forwarding(skb);
2468 static inline void skb_forward_csum(struct sk_buff *skb)
2470 /* Unfortunately we don't support this one. Any brave souls? */
2471 if (skb->ip_summed == CHECKSUM_COMPLETE)
2472 skb->ip_summed = CHECKSUM_NONE;
2476 * skb_checksum_none_assert - make sure skb ip_summed is CHECKSUM_NONE
2477 * @skb: skb to check
2479 * fresh skbs have their ip_summed set to CHECKSUM_NONE.
2480 * Instead of forcing ip_summed to CHECKSUM_NONE, we can
2481 * use this helper, to document places where we make this assertion.
2483 static inline void skb_checksum_none_assert(const struct sk_buff *skb)
2486 BUG_ON(skb->ip_summed != CHECKSUM_NONE);
2490 bool skb_partial_csum_set(struct sk_buff *skb, u16 start, u16 off);
2492 static inline bool skb_is_recycleable(const struct sk_buff *skb, int skb_size)
2494 if (irqs_disabled())
2497 if (skb_shinfo(skb)->tx_flags & SKBTX_DEV_ZEROCOPY)
2500 if (skb_is_nonlinear(skb) || skb->fclone != SKB_FCLONE_UNAVAILABLE)
2503 skb_size = SKB_DATA_ALIGN(skb_size + NET_SKB_PAD);
2504 if (skb_end_pointer(skb) - skb->head < skb_size)
2507 if (skb_shared(skb) || skb_cloned(skb))
2512 #endif /* __KERNEL__ */
2513 #endif /* _LINUX_SKBUFF_H */