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1 /*
2 * Definitions for the 'struct sk_buff' memory handlers.
3 *
4 * Authors:
5 * Alan Cox, <gw4pts@gw4pts.ampr.org>
6 * Florian La Roche, <rzsfl@rz.uni-sb.de>
7 *
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.
12 */
13
14 #ifndef _LINUX_SKBUFF_H
15 #define _LINUX_SKBUFF_H
16
17 #include <linux/kernel.h>
18 #include <linux/kmemcheck.h>
19 #include <linux/compiler.h>
20 #include <linux/time.h>
21 #include <linux/bug.h>
22 #include <linux/cache.h>
23
24 #include <linux/atomic.h>
25 #include <asm/types.h>
26 #include <linux/spinlock.h>
27 #include <linux/net.h>
28 #include <linux/textsearch.h>
29 #include <net/checksum.h>
30 #include <linux/rcupdate.h>
31 #include <linux/dmaengine.h>
32 #include <linux/hrtimer.h>
33 #include <linux/dma-mapping.h>
34 #include <linux/netdev_features.h>
35
36 /* Don't change this without changing skb_csum_unnecessary! */
37 #define CHECKSUM_NONE 0
38 #define CHECKSUM_UNNECESSARY 1
39 #define CHECKSUM_COMPLETE 2
40 #define CHECKSUM_PARTIAL 3
41
42 #define SKB_DATA_ALIGN(X) (((X) + (SMP_CACHE_BYTES - 1)) & \
43 ~(SMP_CACHE_BYTES - 1))
44 #define SKB_WITH_OVERHEAD(X) \
45 ((X) - SKB_DATA_ALIGN(sizeof(struct skb_shared_info)))
46 #define SKB_MAX_ORDER(X, ORDER) \
47 SKB_WITH_OVERHEAD((PAGE_SIZE << (ORDER)) - (X))
48 #define SKB_MAX_HEAD(X) (SKB_MAX_ORDER((X), 0))
49 #define SKB_MAX_ALLOC (SKB_MAX_ORDER(0, 2))
50
51 /* return minimum truesize of one skb containing X bytes of data */
52 #define SKB_TRUESIZE(X) ((X) + \
53 SKB_DATA_ALIGN(sizeof(struct sk_buff)) + \
54 SKB_DATA_ALIGN(sizeof(struct skb_shared_info)))
55
56 /* A. Checksumming of received packets by device.
57 *
58 * NONE: device failed to checksum this packet.
59 * skb->csum is undefined.
60 *
61 * UNNECESSARY: device parsed packet and wouldbe verified checksum.
62 * skb->csum is undefined.
63 * It is bad option, but, unfortunately, many of vendors do this.
64 * Apparently with secret goal to sell you new device, when you
65 * will add new protocol to your host. F.e. IPv6. 8)
66 *
67 * COMPLETE: the most generic way. Device supplied checksum of _all_
68 * the packet as seen by netif_rx in skb->csum.
69 * NOTE: Even if device supports only some protocols, but
70 * is able to produce some skb->csum, it MUST use COMPLETE,
71 * not UNNECESSARY.
72 *
73 * PARTIAL: identical to the case for output below. This may occur
74 * on a packet received directly from another Linux OS, e.g.,
75 * a virtualised Linux kernel on the same host. The packet can
76 * be treated in the same way as UNNECESSARY except that on
77 * output (i.e., forwarding) the checksum must be filled in
78 * by the OS or the hardware.
79 *
80 * B. Checksumming on output.
81 *
82 * NONE: skb is checksummed by protocol or csum is not required.
83 *
84 * PARTIAL: device is required to csum packet as seen by hard_start_xmit
85 * from skb->csum_start to the end and to record the checksum
86 * at skb->csum_start + skb->csum_offset.
87 *
88 * Device must show its capabilities in dev->features, set
89 * at device setup time.
90 * NETIF_F_HW_CSUM - it is clever device, it is able to checksum
91 * everything.
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.
97 *
98 * UNNECESSARY: device will do per protocol specific csum. Protocol drivers
99 * that do not want net to perform the checksum calculation should use
100 * this flag in their outgoing skbs.
101 * NETIF_F_FCOE_CRC this indicates the device can do FCoE FC CRC
102 * offload. Correspondingly, the FCoE protocol driver
103 * stack should use CHECKSUM_UNNECESSARY.
104 *
105 * Any questions? No questions, good. --ANK
106 */
107
108 struct net_device;
109 struct scatterlist;
110 struct pipe_inode_info;
111
112 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
113 struct nf_conntrack {
114 atomic_t use;
115 };
116 #endif
117
118 #ifdef CONFIG_BRIDGE_NETFILTER
119 struct nf_bridge_info {
120 atomic_t use;
121 unsigned int mask;
122 struct net_device *physindev;
123 struct net_device *physoutdev;
124 unsigned long data[32 / sizeof(unsigned long)];
125 };
126 #endif
127
128 struct sk_buff_head {
129 /* These two members must be first. */
130 struct sk_buff *next;
131 struct sk_buff *prev;
132
133 __u32 qlen;
134 spinlock_t lock;
135 };
136
137 struct sk_buff;
138
139 /* To allow 64K frame to be packed as single skb without frag_list we
140 * require 64K/PAGE_SIZE pages plus 1 additional page to allow for
141 * buffers which do not start on a page boundary.
142 *
143 * Since GRO uses frags we allocate at least 16 regardless of page
144 * size.
145 */
146 #if (65536/PAGE_SIZE + 1) < 16
147 #define MAX_SKB_FRAGS 16UL
148 #else
149 #define MAX_SKB_FRAGS (65536/PAGE_SIZE + 1)
150 #endif
151
152 typedef struct skb_frag_struct skb_frag_t;
153
154 struct skb_frag_struct {
155 struct {
156 struct page *p;
157 } page;
158 #if (BITS_PER_LONG > 32) || (PAGE_SIZE >= 65536)
159 __u32 page_offset;
160 __u32 size;
161 #else
162 __u16 page_offset;
163 __u16 size;
164 #endif
165 };
166
167 static inline unsigned int skb_frag_size(const skb_frag_t *frag)
168 {
169 return frag->size;
170 }
171
172 static inline void skb_frag_size_set(skb_frag_t *frag, unsigned int size)
173 {
174 frag->size = size;
175 }
176
177 static inline void skb_frag_size_add(skb_frag_t *frag, int delta)
178 {
179 frag->size += delta;
180 }
181
182 static inline void skb_frag_size_sub(skb_frag_t *frag, int delta)
183 {
184 frag->size -= delta;
185 }
186
187 #define HAVE_HW_TIME_STAMP
188
189 /**
190 * struct skb_shared_hwtstamps - hardware time stamps
191 * @hwtstamp: hardware time stamp transformed into duration
192 * since arbitrary point in time
193 * @syststamp: hwtstamp transformed to system time base
194 *
195 * Software time stamps generated by ktime_get_real() are stored in
196 * skb->tstamp. The relation between the different kinds of time
197 * stamps is as follows:
198 *
199 * syststamp and tstamp can be compared against each other in
200 * arbitrary combinations. The accuracy of a
201 * syststamp/tstamp/"syststamp from other device" comparison is
202 * limited by the accuracy of the transformation into system time
203 * base. This depends on the device driver and its underlying
204 * hardware.
205 *
206 * hwtstamps can only be compared against other hwtstamps from
207 * the same device.
208 *
209 * This structure is attached to packets as part of the
210 * &skb_shared_info. Use skb_hwtstamps() to get a pointer.
211 */
212 struct skb_shared_hwtstamps {
213 ktime_t hwtstamp;
214 ktime_t syststamp;
215 };
216
217 /* Definitions for tx_flags in struct skb_shared_info */
218 enum {
219 /* generate hardware time stamp */
220 SKBTX_HW_TSTAMP = 1 << 0,
221
222 /* generate software time stamp */
223 SKBTX_SW_TSTAMP = 1 << 1,
224
225 /* device driver is going to provide hardware time stamp */
226 SKBTX_IN_PROGRESS = 1 << 2,
227
228 /* device driver supports TX zero-copy buffers */
229 SKBTX_DEV_ZEROCOPY = 1 << 3,
230
231 /* generate wifi status information (where possible) */
232 SKBTX_WIFI_STATUS = 1 << 4,
233 };
234
235 /*
236 * The callback notifies userspace to release buffers when skb DMA is done in
237 * lower device, the skb last reference should be 0 when calling this.
238 * The ctx field is used to track device context.
239 * The desc field is used to track userspace buffer index.
240 */
241 struct ubuf_info {
242 void (*callback)(struct ubuf_info *);
243 void *ctx;
244 unsigned long desc;
245 };
246
247 /* This data is invariant across clones and lives at
248 * the end of the header data, ie. at skb->end.
249 */
250 struct skb_shared_info {
251 unsigned char nr_frags;
252 __u8 tx_flags;
253 unsigned short gso_size;
254 /* Warning: this field is not always filled in (UFO)! */
255 unsigned short gso_segs;
256 unsigned short gso_type;
257 struct sk_buff *frag_list;
258 struct skb_shared_hwtstamps hwtstamps;
259 __be32 ip6_frag_id;
260
261 /*
262 * Warning : all fields before dataref are cleared in __alloc_skb()
263 */
264 atomic_t dataref;
265
266 /* Intermediate layers must ensure that destructor_arg
267 * remains valid until skb destructor */
268 void * destructor_arg;
269
270 /* must be last field, see pskb_expand_head() */
271 skb_frag_t frags[MAX_SKB_FRAGS];
272 };
273
274 /* We divide dataref into two halves. The higher 16 bits hold references
275 * to the payload part of skb->data. The lower 16 bits hold references to
276 * the entire skb->data. A clone of a headerless skb holds the length of
277 * the header in skb->hdr_len.
278 *
279 * All users must obey the rule that the skb->data reference count must be
280 * greater than or equal to the payload reference count.
281 *
282 * Holding a reference to the payload part means that the user does not
283 * care about modifications to the header part of skb->data.
284 */
285 #define SKB_DATAREF_SHIFT 16
286 #define SKB_DATAREF_MASK ((1 << SKB_DATAREF_SHIFT) - 1)
287
288
289 enum {
290 SKB_FCLONE_UNAVAILABLE,
291 SKB_FCLONE_ORIG,
292 SKB_FCLONE_CLONE,
293 };
294
295 enum {
296 SKB_GSO_TCPV4 = 1 << 0,
297 SKB_GSO_UDP = 1 << 1,
298
299 /* This indicates the skb is from an untrusted source. */
300 SKB_GSO_DODGY = 1 << 2,
301
302 /* This indicates the tcp segment has CWR set. */
303 SKB_GSO_TCP_ECN = 1 << 3,
304
305 SKB_GSO_TCPV6 = 1 << 4,
306
307 SKB_GSO_FCOE = 1 << 5,
308 };
309
310 #if BITS_PER_LONG > 32
311 #define NET_SKBUFF_DATA_USES_OFFSET 1
312 #endif
313
314 #ifdef NET_SKBUFF_DATA_USES_OFFSET
315 typedef unsigned int sk_buff_data_t;
316 #else
317 typedef unsigned char *sk_buff_data_t;
318 #endif
319
320 #if defined(CONFIG_NF_DEFRAG_IPV4) || defined(CONFIG_NF_DEFRAG_IPV4_MODULE) || \
321 defined(CONFIG_NF_DEFRAG_IPV6) || defined(CONFIG_NF_DEFRAG_IPV6_MODULE)
322 #define NET_SKBUFF_NF_DEFRAG_NEEDED 1
323 #endif
324
325 /**
326 * struct sk_buff - socket buffer
327 * @next: Next buffer in list
328 * @prev: Previous buffer in list
329 * @tstamp: Time we arrived
330 * @sk: Socket we are owned by
331 * @dev: Device we arrived on/are leaving by
332 * @cb: Control buffer. Free for use by every layer. Put private vars here
333 * @_skb_refdst: destination entry (with norefcount bit)
334 * @sp: the security path, used for xfrm
335 * @len: Length of actual data
336 * @data_len: Data length
337 * @mac_len: Length of link layer header
338 * @hdr_len: writable header length of cloned skb
339 * @csum: Checksum (must include start/offset pair)
340 * @csum_start: Offset from skb->head where checksumming should start
341 * @csum_offset: Offset from csum_start where checksum should be stored
342 * @priority: Packet queueing priority
343 * @local_df: allow local fragmentation
344 * @cloned: Head may be cloned (check refcnt to be sure)
345 * @ip_summed: Driver fed us an IP checksum
346 * @nohdr: Payload reference only, must not modify header
347 * @nfctinfo: Relationship of this skb to the connection
348 * @pkt_type: Packet class
349 * @fclone: skbuff clone status
350 * @ipvs_property: skbuff is owned by ipvs
351 * @peeked: this packet has been seen already, so stats have been
352 * done for it, don't do them again
353 * @nf_trace: netfilter packet trace flag
354 * @protocol: Packet protocol from driver
355 * @destructor: Destruct function
356 * @nfct: Associated connection, if any
357 * @nfct_reasm: netfilter conntrack re-assembly pointer
358 * @nf_bridge: Saved data about a bridged frame - see br_netfilter.c
359 * @skb_iif: ifindex of device we arrived on
360 * @tc_index: Traffic control index
361 * @tc_verd: traffic control verdict
362 * @rxhash: the packet hash computed on receive
363 * @queue_mapping: Queue mapping for multiqueue devices
364 * @ndisc_nodetype: router type (from link layer)
365 * @ooo_okay: allow the mapping of a socket to a queue to be changed
366 * @l4_rxhash: indicate rxhash is a canonical 4-tuple hash over transport
367 * ports.
368 * @wifi_acked_valid: wifi_acked was set
369 * @wifi_acked: whether frame was acked on wifi or not
370 * @no_fcs: Request NIC to treat last 4 bytes as Ethernet FCS
371 * @dma_cookie: a cookie to one of several possible DMA operations
372 * done by skb DMA functions
373 * @secmark: security marking
374 * @mark: Generic packet mark
375 * @dropcount: total number of sk_receive_queue overflows
376 * @vlan_tci: vlan tag control information
377 * @transport_header: Transport layer header
378 * @network_header: Network layer header
379 * @mac_header: Link layer header
380 * @tail: Tail pointer
381 * @end: End pointer
382 * @head: Head of buffer
383 * @data: Data head pointer
384 * @truesize: Buffer size
385 * @users: User count - see {datagram,tcp}.c
386 */
387
388 struct sk_buff {
389 /* These two members must be first. */
390 struct sk_buff *next;
391 struct sk_buff *prev;
392
393 ktime_t tstamp;
394
395 struct sock *sk;
396 struct net_device *dev;
397
398 /*
399 * This is the control buffer. It is free to use for every
400 * layer. Please put your private variables there. If you
401 * want to keep them across layers you have to do a skb_clone()
402 * first. This is owned by whoever has the skb queued ATM.
403 */
404 char cb[48] __aligned(8);
405
406 unsigned long _skb_refdst;
407 #ifdef CONFIG_XFRM
408 struct sec_path *sp;
409 #endif
410 unsigned int len,
411 data_len;
412 __u16 mac_len,
413 hdr_len;
414 union {
415 __wsum csum;
416 struct {
417 __u16 csum_start;
418 __u16 csum_offset;
419 };
420 };
421 __u32 priority;
422 kmemcheck_bitfield_begin(flags1);
423 __u8 local_df:1,
424 cloned:1,
425 ip_summed:2,
426 nohdr:1,
427 nfctinfo:3;
428 __u8 pkt_type:3,
429 fclone:2,
430 ipvs_property:1,
431 peeked:1,
432 nf_trace:1;
433 kmemcheck_bitfield_end(flags1);
434 __be16 protocol;
435
436 void (*destructor)(struct sk_buff *skb);
437 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
438 struct nf_conntrack *nfct;
439 #endif
440 #ifdef NET_SKBUFF_NF_DEFRAG_NEEDED
441 struct sk_buff *nfct_reasm;
442 #endif
443 #ifdef CONFIG_BRIDGE_NETFILTER
444 struct nf_bridge_info *nf_bridge;
445 #endif
446
447 int skb_iif;
448
449 __u32 rxhash;
450
451 __u16 vlan_tci;
452
453 #ifdef CONFIG_NET_SCHED
454 __u16 tc_index; /* traffic control index */
455 #ifdef CONFIG_NET_CLS_ACT
456 __u16 tc_verd; /* traffic control verdict */
457 #endif
458 #endif
459
460 __u16 queue_mapping;
461 kmemcheck_bitfield_begin(flags2);
462 #ifdef CONFIG_IPV6_NDISC_NODETYPE
463 __u8 ndisc_nodetype:2;
464 #endif
465 __u8 pfmemalloc:1;
466 __u8 ooo_okay:1;
467 __u8 l4_rxhash:1;
468 __u8 wifi_acked_valid:1;
469 __u8 wifi_acked:1;
470 __u8 no_fcs:1;
471 __u8 head_frag:1;
472 /* 8/10 bit hole (depending on ndisc_nodetype presence) */
473 kmemcheck_bitfield_end(flags2);
474
475 #ifdef CONFIG_NET_DMA
476 dma_cookie_t dma_cookie;
477 #endif
478 #ifdef CONFIG_NETWORK_SECMARK
479 __u32 secmark;
480 #endif
481 union {
482 __u32 mark;
483 __u32 dropcount;
484 __u32 avail_size;
485 };
486
487 sk_buff_data_t transport_header;
488 sk_buff_data_t network_header;
489 sk_buff_data_t mac_header;
490 /* These elements must be at the end, see alloc_skb() for details. */
491 sk_buff_data_t tail;
492 sk_buff_data_t end;
493 unsigned char *head,
494 *data;
495 unsigned int truesize;
496 atomic_t users;
497 };
498
499 #ifdef __KERNEL__
500 /*
501 * Handling routines are only of interest to the kernel
502 */
503 #include <linux/slab.h>
504
505
506 #define SKB_ALLOC_FCLONE 0x01
507 #define SKB_ALLOC_RX 0x02
508
509 /* Returns true if the skb was allocated from PFMEMALLOC reserves */
510 static inline bool skb_pfmemalloc(const struct sk_buff *skb)
511 {
512 return unlikely(skb->pfmemalloc);
513 }
514
515 /*
516 * skb might have a dst pointer attached, refcounted or not.
517 * _skb_refdst low order bit is set if refcount was _not_ taken
518 */
519 #define SKB_DST_NOREF 1UL
520 #define SKB_DST_PTRMASK ~(SKB_DST_NOREF)
521
522 /**
523 * skb_dst - returns skb dst_entry
524 * @skb: buffer
525 *
526 * Returns skb dst_entry, regardless of reference taken or not.
527 */
528 static inline struct dst_entry *skb_dst(const struct sk_buff *skb)
529 {
530 /* If refdst was not refcounted, check we still are in a
531 * rcu_read_lock section
532 */
533 WARN_ON((skb->_skb_refdst & SKB_DST_NOREF) &&
534 !rcu_read_lock_held() &&
535 !rcu_read_lock_bh_held());
536 return (struct dst_entry *)(skb->_skb_refdst & SKB_DST_PTRMASK);
537 }
538
539 /**
540 * skb_dst_set - sets skb dst
541 * @skb: buffer
542 * @dst: dst entry
543 *
544 * Sets skb dst, assuming a reference was taken on dst and should
545 * be released by skb_dst_drop()
546 */
547 static inline void skb_dst_set(struct sk_buff *skb, struct dst_entry *dst)
548 {
549 skb->_skb_refdst = (unsigned long)dst;
550 }
551
552 extern void skb_dst_set_noref(struct sk_buff *skb, struct dst_entry *dst);
553
554 /**
555 * skb_dst_is_noref - Test if skb dst isn't refcounted
556 * @skb: buffer
557 */
558 static inline bool skb_dst_is_noref(const struct sk_buff *skb)
559 {
560 return (skb->_skb_refdst & SKB_DST_NOREF) && skb_dst(skb);
561 }
562
563 static inline struct rtable *skb_rtable(const struct sk_buff *skb)
564 {
565 return (struct rtable *)skb_dst(skb);
566 }
567
568 extern void kfree_skb(struct sk_buff *skb);
569 extern void consume_skb(struct sk_buff *skb);
570 extern void __kfree_skb(struct sk_buff *skb);
571 extern struct kmem_cache *skbuff_head_cache;
572
573 extern void kfree_skb_partial(struct sk_buff *skb, bool head_stolen);
574 extern bool skb_try_coalesce(struct sk_buff *to, struct sk_buff *from,
575 bool *fragstolen, int *delta_truesize);
576
577 extern struct sk_buff *__alloc_skb(unsigned int size,
578 gfp_t priority, int flags, int node);
579 extern struct sk_buff *build_skb(void *data, unsigned int frag_size);
580 static inline struct sk_buff *alloc_skb(unsigned int size,
581 gfp_t priority)
582 {
583 return __alloc_skb(size, priority, 0, NUMA_NO_NODE);
584 }
585
586 static inline struct sk_buff *alloc_skb_fclone(unsigned int size,
587 gfp_t priority)
588 {
589 return __alloc_skb(size, priority, SKB_ALLOC_FCLONE, NUMA_NO_NODE);
590 }
591
592 extern void skb_recycle(struct sk_buff *skb);
593 extern bool skb_recycle_check(struct sk_buff *skb, int skb_size);
594
595 extern struct sk_buff *skb_morph(struct sk_buff *dst, struct sk_buff *src);
596 extern int skb_copy_ubufs(struct sk_buff *skb, gfp_t gfp_mask);
597 extern struct sk_buff *skb_clone(struct sk_buff *skb,
598 gfp_t priority);
599 extern struct sk_buff *skb_copy(const struct sk_buff *skb,
600 gfp_t priority);
601 extern struct sk_buff *__pskb_copy(struct sk_buff *skb,
602 int headroom, gfp_t gfp_mask);
603
604 extern int pskb_expand_head(struct sk_buff *skb,
605 int nhead, int ntail,
606 gfp_t gfp_mask);
607 extern struct sk_buff *skb_realloc_headroom(struct sk_buff *skb,
608 unsigned int headroom);
609 extern struct sk_buff *skb_copy_expand(const struct sk_buff *skb,
610 int newheadroom, int newtailroom,
611 gfp_t priority);
612 extern int skb_to_sgvec(struct sk_buff *skb,
613 struct scatterlist *sg, int offset,
614 int len);
615 extern int skb_cow_data(struct sk_buff *skb, int tailbits,
616 struct sk_buff **trailer);
617 extern int skb_pad(struct sk_buff *skb, int pad);
618 #define dev_kfree_skb(a) consume_skb(a)
619
620 extern int skb_append_datato_frags(struct sock *sk, struct sk_buff *skb,
621 int getfrag(void *from, char *to, int offset,
622 int len,int odd, struct sk_buff *skb),
623 void *from, int length);
624
625 struct skb_seq_state {
626 __u32 lower_offset;
627 __u32 upper_offset;
628 __u32 frag_idx;
629 __u32 stepped_offset;
630 struct sk_buff *root_skb;
631 struct sk_buff *cur_skb;
632 __u8 *frag_data;
633 };
634
635 extern void skb_prepare_seq_read(struct sk_buff *skb,
636 unsigned int from, unsigned int to,
637 struct skb_seq_state *st);
638 extern unsigned int skb_seq_read(unsigned int consumed, const u8 **data,
639 struct skb_seq_state *st);
640 extern void skb_abort_seq_read(struct skb_seq_state *st);
641
642 extern unsigned int skb_find_text(struct sk_buff *skb, unsigned int from,
643 unsigned int to, struct ts_config *config,
644 struct ts_state *state);
645
646 extern void __skb_get_rxhash(struct sk_buff *skb);
647 static inline __u32 skb_get_rxhash(struct sk_buff *skb)
648 {
649 if (!skb->rxhash)
650 __skb_get_rxhash(skb);
651
652 return skb->rxhash;
653 }
654
655 #ifdef NET_SKBUFF_DATA_USES_OFFSET
656 static inline unsigned char *skb_end_pointer(const struct sk_buff *skb)
657 {
658 return skb->head + skb->end;
659 }
660
661 static inline unsigned int skb_end_offset(const struct sk_buff *skb)
662 {
663 return skb->end;
664 }
665 #else
666 static inline unsigned char *skb_end_pointer(const struct sk_buff *skb)
667 {
668 return skb->end;
669 }
670
671 static inline unsigned int skb_end_offset(const struct sk_buff *skb)
672 {
673 return skb->end - skb->head;
674 }
675 #endif
676
677 /* Internal */
678 #define skb_shinfo(SKB) ((struct skb_shared_info *)(skb_end_pointer(SKB)))
679
680 static inline struct skb_shared_hwtstamps *skb_hwtstamps(struct sk_buff *skb)
681 {
682 return &skb_shinfo(skb)->hwtstamps;
683 }
684
685 /**
686 * skb_queue_empty - check if a queue is empty
687 * @list: queue head
688 *
689 * Returns true if the queue is empty, false otherwise.
690 */
691 static inline int skb_queue_empty(const struct sk_buff_head *list)
692 {
693 return list->next == (struct sk_buff *)list;
694 }
695
696 /**
697 * skb_queue_is_last - check if skb is the last entry in the queue
698 * @list: queue head
699 * @skb: buffer
700 *
701 * Returns true if @skb is the last buffer on the list.
702 */
703 static inline bool skb_queue_is_last(const struct sk_buff_head *list,
704 const struct sk_buff *skb)
705 {
706 return skb->next == (struct sk_buff *)list;
707 }
708
709 /**
710 * skb_queue_is_first - check if skb is the first entry in the queue
711 * @list: queue head
712 * @skb: buffer
713 *
714 * Returns true if @skb is the first buffer on the list.
715 */
716 static inline bool skb_queue_is_first(const struct sk_buff_head *list,
717 const struct sk_buff *skb)
718 {
719 return skb->prev == (struct sk_buff *)list;
720 }
721
722 /**
723 * skb_queue_next - return the next packet in the queue
724 * @list: queue head
725 * @skb: current buffer
726 *
727 * Return the next packet in @list after @skb. It is only valid to
728 * call this if skb_queue_is_last() evaluates to false.
729 */
730 static inline struct sk_buff *skb_queue_next(const struct sk_buff_head *list,
731 const struct sk_buff *skb)
732 {
733 /* This BUG_ON may seem severe, but if we just return then we
734 * are going to dereference garbage.
735 */
736 BUG_ON(skb_queue_is_last(list, skb));
737 return skb->next;
738 }
739
740 /**
741 * skb_queue_prev - return the prev packet in the queue
742 * @list: queue head
743 * @skb: current buffer
744 *
745 * Return the prev packet in @list before @skb. It is only valid to
746 * call this if skb_queue_is_first() evaluates to false.
747 */
748 static inline struct sk_buff *skb_queue_prev(const struct sk_buff_head *list,
749 const struct sk_buff *skb)
750 {
751 /* This BUG_ON may seem severe, but if we just return then we
752 * are going to dereference garbage.
753 */
754 BUG_ON(skb_queue_is_first(list, skb));
755 return skb->prev;
756 }
757
758 /**
759 * skb_get - reference buffer
760 * @skb: buffer to reference
761 *
762 * Makes another reference to a socket buffer and returns a pointer
763 * to the buffer.
764 */
765 static inline struct sk_buff *skb_get(struct sk_buff *skb)
766 {
767 atomic_inc(&skb->users);
768 return skb;
769 }
770
771 /*
772 * If users == 1, we are the only owner and are can avoid redundant
773 * atomic change.
774 */
775
776 /**
777 * skb_cloned - is the buffer a clone
778 * @skb: buffer to check
779 *
780 * Returns true if the buffer was generated with skb_clone() and is
781 * one of multiple shared copies of the buffer. Cloned buffers are
782 * shared data so must not be written to under normal circumstances.
783 */
784 static inline int skb_cloned(const struct sk_buff *skb)
785 {
786 return skb->cloned &&
787 (atomic_read(&skb_shinfo(skb)->dataref) & SKB_DATAREF_MASK) != 1;
788 }
789
790 /**
791 * skb_header_cloned - is the header a clone
792 * @skb: buffer to check
793 *
794 * Returns true if modifying the header part of the buffer requires
795 * the data to be copied.
796 */
797 static inline int skb_header_cloned(const struct sk_buff *skb)
798 {
799 int dataref;
800
801 if (!skb->cloned)
802 return 0;
803
804 dataref = atomic_read(&skb_shinfo(skb)->dataref);
805 dataref = (dataref & SKB_DATAREF_MASK) - (dataref >> SKB_DATAREF_SHIFT);
806 return dataref != 1;
807 }
808
809 /**
810 * skb_header_release - release reference to header
811 * @skb: buffer to operate on
812 *
813 * Drop a reference to the header part of the buffer. This is done
814 * by acquiring a payload reference. You must not read from the header
815 * part of skb->data after this.
816 */
817 static inline void skb_header_release(struct sk_buff *skb)
818 {
819 BUG_ON(skb->nohdr);
820 skb->nohdr = 1;
821 atomic_add(1 << SKB_DATAREF_SHIFT, &skb_shinfo(skb)->dataref);
822 }
823
824 /**
825 * skb_shared - is the buffer shared
826 * @skb: buffer to check
827 *
828 * Returns true if more than one person has a reference to this
829 * buffer.
830 */
831 static inline int skb_shared(const struct sk_buff *skb)
832 {
833 return atomic_read(&skb->users) != 1;
834 }
835
836 /**
837 * skb_share_check - check if buffer is shared and if so clone it
838 * @skb: buffer to check
839 * @pri: priority for memory allocation
840 *
841 * If the buffer is shared the buffer is cloned and the old copy
842 * drops a reference. A new clone with a single reference is returned.
843 * If the buffer is not shared the original buffer is returned. When
844 * being called from interrupt status or with spinlocks held pri must
845 * be GFP_ATOMIC.
846 *
847 * NULL is returned on a memory allocation failure.
848 */
849 static inline struct sk_buff *skb_share_check(struct sk_buff *skb, gfp_t pri)
850 {
851 might_sleep_if(pri & __GFP_WAIT);
852 if (skb_shared(skb)) {
853 struct sk_buff *nskb = skb_clone(skb, pri);
854
855 if (likely(nskb))
856 consume_skb(skb);
857 else
858 kfree_skb(skb);
859 skb = nskb;
860 }
861 return skb;
862 }
863
864 /*
865 * Copy shared buffers into a new sk_buff. We effectively do COW on
866 * packets to handle cases where we have a local reader and forward
867 * and a couple of other messy ones. The normal one is tcpdumping
868 * a packet thats being forwarded.
869 */
870
871 /**
872 * skb_unshare - make a copy of a shared buffer
873 * @skb: buffer to check
874 * @pri: priority for memory allocation
875 *
876 * If the socket buffer is a clone then this function creates a new
877 * copy of the data, drops a reference count on the old copy and returns
878 * the new copy with the reference count at 1. If the buffer is not a clone
879 * the original buffer is returned. When called with a spinlock held or
880 * from interrupt state @pri must be %GFP_ATOMIC
881 *
882 * %NULL is returned on a memory allocation failure.
883 */
884 static inline struct sk_buff *skb_unshare(struct sk_buff *skb,
885 gfp_t pri)
886 {
887 might_sleep_if(pri & __GFP_WAIT);
888 if (skb_cloned(skb)) {
889 struct sk_buff *nskb = skb_copy(skb, pri);
890 kfree_skb(skb); /* Free our shared copy */
891 skb = nskb;
892 }
893 return skb;
894 }
895
896 /**
897 * skb_peek - peek at the head of an &sk_buff_head
898 * @list_: list to peek at
899 *
900 * Peek an &sk_buff. Unlike most other operations you _MUST_
901 * be careful with this one. A peek leaves the buffer on the
902 * list and someone else may run off with it. You must hold
903 * the appropriate locks or have a private queue to do this.
904 *
905 * Returns %NULL for an empty list or a pointer to the head element.
906 * The reference count is not incremented and the reference is therefore
907 * volatile. Use with caution.
908 */
909 static inline struct sk_buff *skb_peek(const struct sk_buff_head *list_)
910 {
911 struct sk_buff *skb = list_->next;
912
913 if (skb == (struct sk_buff *)list_)
914 skb = NULL;
915 return skb;
916 }
917
918 /**
919 * skb_peek_next - peek skb following the given one from a queue
920 * @skb: skb to start from
921 * @list_: list to peek at
922 *
923 * Returns %NULL when the end of the list is met or a pointer to the
924 * next element. The reference count is not incremented and the
925 * reference is therefore volatile. Use with caution.
926 */
927 static inline struct sk_buff *skb_peek_next(struct sk_buff *skb,
928 const struct sk_buff_head *list_)
929 {
930 struct sk_buff *next = skb->next;
931
932 if (next == (struct sk_buff *)list_)
933 next = NULL;
934 return next;
935 }
936
937 /**
938 * skb_peek_tail - peek at the tail of an &sk_buff_head
939 * @list_: list to peek at
940 *
941 * Peek an &sk_buff. Unlike most other operations you _MUST_
942 * be careful with this one. A peek leaves the buffer on the
943 * list and someone else may run off with it. You must hold
944 * the appropriate locks or have a private queue to do this.
945 *
946 * Returns %NULL for an empty list or a pointer to the tail element.
947 * The reference count is not incremented and the reference is therefore
948 * volatile. Use with caution.
949 */
950 static inline struct sk_buff *skb_peek_tail(const struct sk_buff_head *list_)
951 {
952 struct sk_buff *skb = list_->prev;
953
954 if (skb == (struct sk_buff *)list_)
955 skb = NULL;
956 return skb;
957
958 }
959
960 /**
961 * skb_queue_len - get queue length
962 * @list_: list to measure
963 *
964 * Return the length of an &sk_buff queue.
965 */
966 static inline __u32 skb_queue_len(const struct sk_buff_head *list_)
967 {
968 return list_->qlen;
969 }
970
971 /**
972 * __skb_queue_head_init - initialize non-spinlock portions of sk_buff_head
973 * @list: queue to initialize
974 *
975 * This initializes only the list and queue length aspects of
976 * an sk_buff_head object. This allows to initialize the list
977 * aspects of an sk_buff_head without reinitializing things like
978 * the spinlock. It can also be used for on-stack sk_buff_head
979 * objects where the spinlock is known to not be used.
980 */
981 static inline void __skb_queue_head_init(struct sk_buff_head *list)
982 {
983 list->prev = list->next = (struct sk_buff *)list;
984 list->qlen = 0;
985 }
986
987 /*
988 * This function creates a split out lock class for each invocation;
989 * this is needed for now since a whole lot of users of the skb-queue
990 * infrastructure in drivers have different locking usage (in hardirq)
991 * than the networking core (in softirq only). In the long run either the
992 * network layer or drivers should need annotation to consolidate the
993 * main types of usage into 3 classes.
994 */
995 static inline void skb_queue_head_init(struct sk_buff_head *list)
996 {
997 spin_lock_init(&list->lock);
998 __skb_queue_head_init(list);
999 }
1000
1001 static inline void skb_queue_head_init_class(struct sk_buff_head *list,
1002 struct lock_class_key *class)
1003 {
1004 skb_queue_head_init(list);
1005 lockdep_set_class(&list->lock, class);
1006 }
1007
1008 /*
1009 * Insert an sk_buff on a list.
1010 *
1011 * The "__skb_xxxx()" functions are the non-atomic ones that
1012 * can only be called with interrupts disabled.
1013 */
1014 extern void skb_insert(struct sk_buff *old, struct sk_buff *newsk, struct sk_buff_head *list);
1015 static inline void __skb_insert(struct sk_buff *newsk,
1016 struct sk_buff *prev, struct sk_buff *next,
1017 struct sk_buff_head *list)
1018 {
1019 newsk->next = next;
1020 newsk->prev = prev;
1021 next->prev = prev->next = newsk;
1022 list->qlen++;
1023 }
1024
1025 static inline void __skb_queue_splice(const struct sk_buff_head *list,
1026 struct sk_buff *prev,
1027 struct sk_buff *next)
1028 {
1029 struct sk_buff *first = list->next;
1030 struct sk_buff *last = list->prev;
1031
1032 first->prev = prev;
1033 prev->next = first;
1034
1035 last->next = next;
1036 next->prev = last;
1037 }
1038
1039 /**
1040 * skb_queue_splice - join two skb lists, this is designed for stacks
1041 * @list: the new list to add
1042 * @head: the place to add it in the first list
1043 */
1044 static inline void skb_queue_splice(const struct sk_buff_head *list,
1045 struct sk_buff_head *head)
1046 {
1047 if (!skb_queue_empty(list)) {
1048 __skb_queue_splice(list, (struct sk_buff *) head, head->next);
1049 head->qlen += list->qlen;
1050 }
1051 }
1052
1053 /**
1054 * skb_queue_splice_init - join two skb lists and reinitialise the emptied list
1055 * @list: the new list to add
1056 * @head: the place to add it in the first list
1057 *
1058 * The list at @list is reinitialised
1059 */
1060 static inline void skb_queue_splice_init(struct sk_buff_head *list,
1061 struct sk_buff_head *head)
1062 {
1063 if (!skb_queue_empty(list)) {
1064 __skb_queue_splice(list, (struct sk_buff *) head, head->next);
1065 head->qlen += list->qlen;
1066 __skb_queue_head_init(list);
1067 }
1068 }
1069
1070 /**
1071 * skb_queue_splice_tail - join two skb lists, each list being a queue
1072 * @list: the new list to add
1073 * @head: the place to add it in the first list
1074 */
1075 static inline void skb_queue_splice_tail(const struct sk_buff_head *list,
1076 struct sk_buff_head *head)
1077 {
1078 if (!skb_queue_empty(list)) {
1079 __skb_queue_splice(list, head->prev, (struct sk_buff *) head);
1080 head->qlen += list->qlen;
1081 }
1082 }
1083
1084 /**
1085 * skb_queue_splice_tail_init - join two skb lists and reinitialise the emptied list
1086 * @list: the new list to add
1087 * @head: the place to add it in the first list
1088 *
1089 * Each of the lists is a queue.
1090 * The list at @list is reinitialised
1091 */
1092 static inline void skb_queue_splice_tail_init(struct sk_buff_head *list,
1093 struct sk_buff_head *head)
1094 {
1095 if (!skb_queue_empty(list)) {
1096 __skb_queue_splice(list, head->prev, (struct sk_buff *) head);
1097 head->qlen += list->qlen;
1098 __skb_queue_head_init(list);
1099 }
1100 }
1101
1102 /**
1103 * __skb_queue_after - queue a buffer at the list head
1104 * @list: list to use
1105 * @prev: place after this buffer
1106 * @newsk: buffer to queue
1107 *
1108 * Queue a buffer int the middle of a list. This function takes no locks
1109 * and you must therefore hold required locks before calling it.
1110 *
1111 * A buffer cannot be placed on two lists at the same time.
1112 */
1113 static inline void __skb_queue_after(struct sk_buff_head *list,
1114 struct sk_buff *prev,
1115 struct sk_buff *newsk)
1116 {
1117 __skb_insert(newsk, prev, prev->next, list);
1118 }
1119
1120 extern void skb_append(struct sk_buff *old, struct sk_buff *newsk,
1121 struct sk_buff_head *list);
1122
1123 static inline void __skb_queue_before(struct sk_buff_head *list,
1124 struct sk_buff *next,
1125 struct sk_buff *newsk)
1126 {
1127 __skb_insert(newsk, next->prev, next, list);
1128 }
1129
1130 /**
1131 * __skb_queue_head - queue a buffer at the list head
1132 * @list: list to use
1133 * @newsk: buffer to queue
1134 *
1135 * Queue a buffer at the start of a list. This function takes no locks
1136 * and you must therefore hold required locks before calling it.
1137 *
1138 * A buffer cannot be placed on two lists at the same time.
1139 */
1140 extern void skb_queue_head(struct sk_buff_head *list, struct sk_buff *newsk);
1141 static inline void __skb_queue_head(struct sk_buff_head *list,
1142 struct sk_buff *newsk)
1143 {
1144 __skb_queue_after(list, (struct sk_buff *)list, newsk);
1145 }
1146
1147 /**
1148 * __skb_queue_tail - queue a buffer at the list tail
1149 * @list: list to use
1150 * @newsk: buffer to queue
1151 *
1152 * Queue a buffer at the end of a list. This function takes no locks
1153 * and you must therefore hold required locks before calling it.
1154 *
1155 * A buffer cannot be placed on two lists at the same time.
1156 */
1157 extern void skb_queue_tail(struct sk_buff_head *list, struct sk_buff *newsk);
1158 static inline void __skb_queue_tail(struct sk_buff_head *list,
1159 struct sk_buff *newsk)
1160 {
1161 __skb_queue_before(list, (struct sk_buff *)list, newsk);
1162 }
1163
1164 /*
1165 * remove sk_buff from list. _Must_ be called atomically, and with
1166 * the list known..
1167 */
1168 extern void skb_unlink(struct sk_buff *skb, struct sk_buff_head *list);
1169 static inline void __skb_unlink(struct sk_buff *skb, struct sk_buff_head *list)
1170 {
1171 struct sk_buff *next, *prev;
1172
1173 list->qlen--;
1174 next = skb->next;
1175 prev = skb->prev;
1176 skb->next = skb->prev = NULL;
1177 next->prev = prev;
1178 prev->next = next;
1179 }
1180
1181 /**
1182 * __skb_dequeue - remove from the head of the queue
1183 * @list: list to dequeue from
1184 *
1185 * Remove the head of the list. This function does not take any locks
1186 * so must be used with appropriate locks held only. The head item is
1187 * returned or %NULL if the list is empty.
1188 */
1189 extern struct sk_buff *skb_dequeue(struct sk_buff_head *list);
1190 static inline struct sk_buff *__skb_dequeue(struct sk_buff_head *list)
1191 {
1192 struct sk_buff *skb = skb_peek(list);
1193 if (skb)
1194 __skb_unlink(skb, list);
1195 return skb;
1196 }
1197
1198 /**
1199 * __skb_dequeue_tail - remove from the tail of the queue
1200 * @list: list to dequeue from
1201 *
1202 * Remove the tail of the list. This function does not take any locks
1203 * so must be used with appropriate locks held only. The tail item is
1204 * returned or %NULL if the list is empty.
1205 */
1206 extern struct sk_buff *skb_dequeue_tail(struct sk_buff_head *list);
1207 static inline struct sk_buff *__skb_dequeue_tail(struct sk_buff_head *list)
1208 {
1209 struct sk_buff *skb = skb_peek_tail(list);
1210 if (skb)
1211 __skb_unlink(skb, list);
1212 return skb;
1213 }
1214
1215
1216 static inline bool skb_is_nonlinear(const struct sk_buff *skb)
1217 {
1218 return skb->data_len;
1219 }
1220
1221 static inline unsigned int skb_headlen(const struct sk_buff *skb)
1222 {
1223 return skb->len - skb->data_len;
1224 }
1225
1226 static inline int skb_pagelen(const struct sk_buff *skb)
1227 {
1228 int i, len = 0;
1229
1230 for (i = (int)skb_shinfo(skb)->nr_frags - 1; i >= 0; i--)
1231 len += skb_frag_size(&skb_shinfo(skb)->frags[i]);
1232 return len + skb_headlen(skb);
1233 }
1234
1235 /**
1236 * __skb_fill_page_desc - initialise a paged fragment in an skb
1237 * @skb: buffer containing fragment to be initialised
1238 * @i: paged fragment index to initialise
1239 * @page: the page to use for this fragment
1240 * @off: the offset to the data with @page
1241 * @size: the length of the data
1242 *
1243 * Initialises the @i'th fragment of @skb to point to &size bytes at
1244 * offset @off within @page.
1245 *
1246 * Does not take any additional reference on the fragment.
1247 */
1248 static inline void __skb_fill_page_desc(struct sk_buff *skb, int i,
1249 struct page *page, int off, int size)
1250 {
1251 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
1252
1253 /*
1254 * Propagate page->pfmemalloc to the skb if we can. The problem is
1255 * that not all callers have unique ownership of the page. If
1256 * pfmemalloc is set, we check the mapping as a mapping implies
1257 * page->index is set (index and pfmemalloc share space).
1258 * If it's a valid mapping, we cannot use page->pfmemalloc but we
1259 * do not lose pfmemalloc information as the pages would not be
1260 * allocated using __GFP_MEMALLOC.
1261 */
1262 if (page->pfmemalloc && !page->mapping)
1263 skb->pfmemalloc = true;
1264 frag->page.p = page;
1265 frag->page_offset = off;
1266 skb_frag_size_set(frag, size);
1267 }
1268
1269 /**
1270 * skb_fill_page_desc - initialise a paged fragment in an skb
1271 * @skb: buffer containing fragment to be initialised
1272 * @i: paged fragment index to initialise
1273 * @page: the page to use for this fragment
1274 * @off: the offset to the data with @page
1275 * @size: the length of the data
1276 *
1277 * As per __skb_fill_page_desc() -- initialises the @i'th fragment of
1278 * @skb to point to &size bytes at offset @off within @page. In
1279 * addition updates @skb such that @i is the last fragment.
1280 *
1281 * Does not take any additional reference on the fragment.
1282 */
1283 static inline void skb_fill_page_desc(struct sk_buff *skb, int i,
1284 struct page *page, int off, int size)
1285 {
1286 __skb_fill_page_desc(skb, i, page, off, size);
1287 skb_shinfo(skb)->nr_frags = i + 1;
1288 }
1289
1290 extern void skb_add_rx_frag(struct sk_buff *skb, int i, struct page *page,
1291 int off, int size, unsigned int truesize);
1292
1293 #define SKB_PAGE_ASSERT(skb) BUG_ON(skb_shinfo(skb)->nr_frags)
1294 #define SKB_FRAG_ASSERT(skb) BUG_ON(skb_has_frag_list(skb))
1295 #define SKB_LINEAR_ASSERT(skb) BUG_ON(skb_is_nonlinear(skb))
1296
1297 #ifdef NET_SKBUFF_DATA_USES_OFFSET
1298 static inline unsigned char *skb_tail_pointer(const struct sk_buff *skb)
1299 {
1300 return skb->head + skb->tail;
1301 }
1302
1303 static inline void skb_reset_tail_pointer(struct sk_buff *skb)
1304 {
1305 skb->tail = skb->data - skb->head;
1306 }
1307
1308 static inline void skb_set_tail_pointer(struct sk_buff *skb, const int offset)
1309 {
1310 skb_reset_tail_pointer(skb);
1311 skb->tail += offset;
1312 }
1313 #else /* NET_SKBUFF_DATA_USES_OFFSET */
1314 static inline unsigned char *skb_tail_pointer(const struct sk_buff *skb)
1315 {
1316 return skb->tail;
1317 }
1318
1319 static inline void skb_reset_tail_pointer(struct sk_buff *skb)
1320 {
1321 skb->tail = skb->data;
1322 }
1323
1324 static inline void skb_set_tail_pointer(struct sk_buff *skb, const int offset)
1325 {
1326 skb->tail = skb->data + offset;
1327 }
1328
1329 #endif /* NET_SKBUFF_DATA_USES_OFFSET */
1330
1331 /*
1332 * Add data to an sk_buff
1333 */
1334 extern unsigned char *skb_put(struct sk_buff *skb, unsigned int len);
1335 static inline unsigned char *__skb_put(struct sk_buff *skb, unsigned int len)
1336 {
1337 unsigned char *tmp = skb_tail_pointer(skb);
1338 SKB_LINEAR_ASSERT(skb);
1339 skb->tail += len;
1340 skb->len += len;
1341 return tmp;
1342 }
1343
1344 extern unsigned char *skb_push(struct sk_buff *skb, unsigned int len);
1345 static inline unsigned char *__skb_push(struct sk_buff *skb, unsigned int len)
1346 {
1347 skb->data -= len;
1348 skb->len += len;
1349 return skb->data;
1350 }
1351
1352 extern unsigned char *skb_pull(struct sk_buff *skb, unsigned int len);
1353 static inline unsigned char *__skb_pull(struct sk_buff *skb, unsigned int len)
1354 {
1355 skb->len -= len;
1356 BUG_ON(skb->len < skb->data_len);
1357 return skb->data += len;
1358 }
1359
1360 static inline unsigned char *skb_pull_inline(struct sk_buff *skb, unsigned int len)
1361 {
1362 return unlikely(len > skb->len) ? NULL : __skb_pull(skb, len);
1363 }
1364
1365 extern unsigned char *__pskb_pull_tail(struct sk_buff *skb, int delta);
1366
1367 static inline unsigned char *__pskb_pull(struct sk_buff *skb, unsigned int len)
1368 {
1369 if (len > skb_headlen(skb) &&
1370 !__pskb_pull_tail(skb, len - skb_headlen(skb)))
1371 return NULL;
1372 skb->len -= len;
1373 return skb->data += len;
1374 }
1375
1376 static inline unsigned char *pskb_pull(struct sk_buff *skb, unsigned int len)
1377 {
1378 return unlikely(len > skb->len) ? NULL : __pskb_pull(skb, len);
1379 }
1380
1381 static inline int pskb_may_pull(struct sk_buff *skb, unsigned int len)
1382 {
1383 if (likely(len <= skb_headlen(skb)))
1384 return 1;
1385 if (unlikely(len > skb->len))
1386 return 0;
1387 return __pskb_pull_tail(skb, len - skb_headlen(skb)) != NULL;
1388 }
1389
1390 /**
1391 * skb_headroom - bytes at buffer head
1392 * @skb: buffer to check
1393 *
1394 * Return the number of bytes of free space at the head of an &sk_buff.
1395 */
1396 static inline unsigned int skb_headroom(const struct sk_buff *skb)
1397 {
1398 return skb->data - skb->head;
1399 }
1400
1401 /**
1402 * skb_tailroom - bytes at buffer end
1403 * @skb: buffer to check
1404 *
1405 * Return the number of bytes of free space at the tail of an sk_buff
1406 */
1407 static inline int skb_tailroom(const struct sk_buff *skb)
1408 {
1409 return skb_is_nonlinear(skb) ? 0 : skb->end - skb->tail;
1410 }
1411
1412 /**
1413 * skb_availroom - bytes at buffer end
1414 * @skb: buffer to check
1415 *
1416 * Return the number of bytes of free space at the tail of an sk_buff
1417 * allocated by sk_stream_alloc()
1418 */
1419 static inline int skb_availroom(const struct sk_buff *skb)
1420 {
1421 return skb_is_nonlinear(skb) ? 0 : skb->avail_size - skb->len;
1422 }
1423
1424 /**
1425 * skb_reserve - adjust headroom
1426 * @skb: buffer to alter
1427 * @len: bytes to move
1428 *
1429 * Increase the headroom of an empty &sk_buff by reducing the tail
1430 * room. This is only allowed for an empty buffer.
1431 */
1432 static inline void skb_reserve(struct sk_buff *skb, int len)
1433 {
1434 skb->data += len;
1435 skb->tail += len;
1436 }
1437
1438 static inline void skb_reset_mac_len(struct sk_buff *skb)
1439 {
1440 skb->mac_len = skb->network_header - skb->mac_header;
1441 }
1442
1443 #ifdef NET_SKBUFF_DATA_USES_OFFSET
1444 static inline unsigned char *skb_transport_header(const struct sk_buff *skb)
1445 {
1446 return skb->head + skb->transport_header;
1447 }
1448
1449 static inline void skb_reset_transport_header(struct sk_buff *skb)
1450 {
1451 skb->transport_header = skb->data - skb->head;
1452 }
1453
1454 static inline void skb_set_transport_header(struct sk_buff *skb,
1455 const int offset)
1456 {
1457 skb_reset_transport_header(skb);
1458 skb->transport_header += offset;
1459 }
1460
1461 static inline unsigned char *skb_network_header(const struct sk_buff *skb)
1462 {
1463 return skb->head + skb->network_header;
1464 }
1465
1466 static inline void skb_reset_network_header(struct sk_buff *skb)
1467 {
1468 skb->network_header = skb->data - skb->head;
1469 }
1470
1471 static inline void skb_set_network_header(struct sk_buff *skb, const int offset)
1472 {
1473 skb_reset_network_header(skb);
1474 skb->network_header += offset;
1475 }
1476
1477 static inline unsigned char *skb_mac_header(const struct sk_buff *skb)
1478 {
1479 return skb->head + skb->mac_header;
1480 }
1481
1482 static inline int skb_mac_header_was_set(const struct sk_buff *skb)
1483 {
1484 return skb->mac_header != ~0U;
1485 }
1486
1487 static inline void skb_reset_mac_header(struct sk_buff *skb)
1488 {
1489 skb->mac_header = skb->data - skb->head;
1490 }
1491
1492 static inline void skb_set_mac_header(struct sk_buff *skb, const int offset)
1493 {
1494 skb_reset_mac_header(skb);
1495 skb->mac_header += offset;
1496 }
1497
1498 #else /* NET_SKBUFF_DATA_USES_OFFSET */
1499
1500 static inline unsigned char *skb_transport_header(const struct sk_buff *skb)
1501 {
1502 return skb->transport_header;
1503 }
1504
1505 static inline void skb_reset_transport_header(struct sk_buff *skb)
1506 {
1507 skb->transport_header = skb->data;
1508 }
1509
1510 static inline void skb_set_transport_header(struct sk_buff *skb,
1511 const int offset)
1512 {
1513 skb->transport_header = skb->data + offset;
1514 }
1515
1516 static inline unsigned char *skb_network_header(const struct sk_buff *skb)
1517 {
1518 return skb->network_header;
1519 }
1520
1521 static inline void skb_reset_network_header(struct sk_buff *skb)
1522 {
1523 skb->network_header = skb->data;
1524 }
1525
1526 static inline void skb_set_network_header(struct sk_buff *skb, const int offset)
1527 {
1528 skb->network_header = skb->data + offset;
1529 }
1530
1531 static inline unsigned char *skb_mac_header(const struct sk_buff *skb)
1532 {
1533 return skb->mac_header;
1534 }
1535
1536 static inline int skb_mac_header_was_set(const struct sk_buff *skb)
1537 {
1538 return skb->mac_header != NULL;
1539 }
1540
1541 static inline void skb_reset_mac_header(struct sk_buff *skb)
1542 {
1543 skb->mac_header = skb->data;
1544 }
1545
1546 static inline void skb_set_mac_header(struct sk_buff *skb, const int offset)
1547 {
1548 skb->mac_header = skb->data + offset;
1549 }
1550 #endif /* NET_SKBUFF_DATA_USES_OFFSET */
1551
1552 static inline void skb_mac_header_rebuild(struct sk_buff *skb)
1553 {
1554 if (skb_mac_header_was_set(skb)) {
1555 const unsigned char *old_mac = skb_mac_header(skb);
1556
1557 skb_set_mac_header(skb, -skb->mac_len);
1558 memmove(skb_mac_header(skb), old_mac, skb->mac_len);
1559 }
1560 }
1561
1562 static inline int skb_checksum_start_offset(const struct sk_buff *skb)
1563 {
1564 return skb->csum_start - skb_headroom(skb);
1565 }
1566
1567 static inline int skb_transport_offset(const struct sk_buff *skb)
1568 {
1569 return skb_transport_header(skb) - skb->data;
1570 }
1571
1572 static inline u32 skb_network_header_len(const struct sk_buff *skb)
1573 {
1574 return skb->transport_header - skb->network_header;
1575 }
1576
1577 static inline int skb_network_offset(const struct sk_buff *skb)
1578 {
1579 return skb_network_header(skb) - skb->data;
1580 }
1581
1582 static inline int pskb_network_may_pull(struct sk_buff *skb, unsigned int len)
1583 {
1584 return pskb_may_pull(skb, skb_network_offset(skb) + len);
1585 }
1586
1587 /*
1588 * CPUs often take a performance hit when accessing unaligned memory
1589 * locations. The actual performance hit varies, it can be small if the
1590 * hardware handles it or large if we have to take an exception and fix it
1591 * in software.
1592 *
1593 * Since an ethernet header is 14 bytes network drivers often end up with
1594 * the IP header at an unaligned offset. The IP header can be aligned by
1595 * shifting the start of the packet by 2 bytes. Drivers should do this
1596 * with:
1597 *
1598 * skb_reserve(skb, NET_IP_ALIGN);
1599 *
1600 * The downside to this alignment of the IP header is that the DMA is now
1601 * unaligned. On some architectures the cost of an unaligned DMA is high
1602 * and this cost outweighs the gains made by aligning the IP header.
1603 *
1604 * Since this trade off varies between architectures, we allow NET_IP_ALIGN
1605 * to be overridden.
1606 */
1607 #ifndef NET_IP_ALIGN
1608 #define NET_IP_ALIGN 2
1609 #endif
1610
1611 /*
1612 * The networking layer reserves some headroom in skb data (via
1613 * dev_alloc_skb). This is used to avoid having to reallocate skb data when
1614 * the header has to grow. In the default case, if the header has to grow
1615 * 32 bytes or less we avoid the reallocation.
1616 *
1617 * Unfortunately this headroom changes the DMA alignment of the resulting
1618 * network packet. As for NET_IP_ALIGN, this unaligned DMA is expensive
1619 * on some architectures. An architecture can override this value,
1620 * perhaps setting it to a cacheline in size (since that will maintain
1621 * cacheline alignment of the DMA). It must be a power of 2.
1622 *
1623 * Various parts of the networking layer expect at least 32 bytes of
1624 * headroom, you should not reduce this.
1625 *
1626 * Using max(32, L1_CACHE_BYTES) makes sense (especially with RPS)
1627 * to reduce average number of cache lines per packet.
1628 * get_rps_cpus() for example only access one 64 bytes aligned block :
1629 * NET_IP_ALIGN(2) + ethernet_header(14) + IP_header(20/40) + ports(8)
1630 */
1631 #ifndef NET_SKB_PAD
1632 #define NET_SKB_PAD max(32, L1_CACHE_BYTES)
1633 #endif
1634
1635 extern int ___pskb_trim(struct sk_buff *skb, unsigned int len);
1636
1637 static inline void __skb_trim(struct sk_buff *skb, unsigned int len)
1638 {
1639 if (unlikely(skb_is_nonlinear(skb))) {
1640 WARN_ON(1);
1641 return;
1642 }
1643 skb->len = len;
1644 skb_set_tail_pointer(skb, len);
1645 }
1646
1647 extern void skb_trim(struct sk_buff *skb, unsigned int len);
1648
1649 static inline int __pskb_trim(struct sk_buff *skb, unsigned int len)
1650 {
1651 if (skb->data_len)
1652 return ___pskb_trim(skb, len);
1653 __skb_trim(skb, len);
1654 return 0;
1655 }
1656
1657 static inline int pskb_trim(struct sk_buff *skb, unsigned int len)
1658 {
1659 return (len < skb->len) ? __pskb_trim(skb, len) : 0;
1660 }
1661
1662 /**
1663 * pskb_trim_unique - remove end from a paged unique (not cloned) buffer
1664 * @skb: buffer to alter
1665 * @len: new length
1666 *
1667 * This is identical to pskb_trim except that the caller knows that
1668 * the skb is not cloned so we should never get an error due to out-
1669 * of-memory.
1670 */
1671 static inline void pskb_trim_unique(struct sk_buff *skb, unsigned int len)
1672 {
1673 int err = pskb_trim(skb, len);
1674 BUG_ON(err);
1675 }
1676
1677 /**
1678 * skb_orphan - orphan a buffer
1679 * @skb: buffer to orphan
1680 *
1681 * If a buffer currently has an owner then we call the owner's
1682 * destructor function and make the @skb unowned. The buffer continues
1683 * to exist but is no longer charged to its former owner.
1684 */
1685 static inline void skb_orphan(struct sk_buff *skb)
1686 {
1687 if (skb->destructor)
1688 skb->destructor(skb);
1689 skb->destructor = NULL;
1690 skb->sk = NULL;
1691 }
1692
1693 /**
1694 * skb_orphan_frags - orphan the frags contained in a buffer
1695 * @skb: buffer to orphan frags from
1696 * @gfp_mask: allocation mask for replacement pages
1697 *
1698 * For each frag in the SKB which needs a destructor (i.e. has an
1699 * owner) create a copy of that frag and release the original
1700 * page by calling the destructor.
1701 */
1702 static inline int skb_orphan_frags(struct sk_buff *skb, gfp_t gfp_mask)
1703 {
1704 if (likely(!(skb_shinfo(skb)->tx_flags & SKBTX_DEV_ZEROCOPY)))
1705 return 0;
1706 return skb_copy_ubufs(skb, gfp_mask);
1707 }
1708
1709 /**
1710 * __skb_queue_purge - empty a list
1711 * @list: list to empty
1712 *
1713 * Delete all buffers on an &sk_buff list. Each buffer is removed from
1714 * the list and one reference dropped. This function does not take the
1715 * list lock and the caller must hold the relevant locks to use it.
1716 */
1717 extern void skb_queue_purge(struct sk_buff_head *list);
1718 static inline void __skb_queue_purge(struct sk_buff_head *list)
1719 {
1720 struct sk_buff *skb;
1721 while ((skb = __skb_dequeue(list)) != NULL)
1722 kfree_skb(skb);
1723 }
1724
1725 extern void *netdev_alloc_frag(unsigned int fragsz);
1726
1727 extern struct sk_buff *__netdev_alloc_skb(struct net_device *dev,
1728 unsigned int length,
1729 gfp_t gfp_mask);
1730
1731 /**
1732 * netdev_alloc_skb - allocate an skbuff for rx on a specific device
1733 * @dev: network device to receive on
1734 * @length: length to allocate
1735 *
1736 * Allocate a new &sk_buff and assign it a usage count of one. The
1737 * buffer has unspecified headroom built in. Users should allocate
1738 * the headroom they think they need without accounting for the
1739 * built in space. The built in space is used for optimisations.
1740 *
1741 * %NULL is returned if there is no free memory. Although this function
1742 * allocates memory it can be called from an interrupt.
1743 */
1744 static inline struct sk_buff *netdev_alloc_skb(struct net_device *dev,
1745 unsigned int length)
1746 {
1747 return __netdev_alloc_skb(dev, length, GFP_ATOMIC);
1748 }
1749
1750 /* legacy helper around __netdev_alloc_skb() */
1751 static inline struct sk_buff *__dev_alloc_skb(unsigned int length,
1752 gfp_t gfp_mask)
1753 {
1754 return __netdev_alloc_skb(NULL, length, gfp_mask);
1755 }
1756
1757 /* legacy helper around netdev_alloc_skb() */
1758 static inline struct sk_buff *dev_alloc_skb(unsigned int length)
1759 {
1760 return netdev_alloc_skb(NULL, length);
1761 }
1762
1763
1764 static inline struct sk_buff *__netdev_alloc_skb_ip_align(struct net_device *dev,
1765 unsigned int length, gfp_t gfp)
1766 {
1767 struct sk_buff *skb = __netdev_alloc_skb(dev, length + NET_IP_ALIGN, gfp);
1768
1769 if (NET_IP_ALIGN && skb)
1770 skb_reserve(skb, NET_IP_ALIGN);
1771 return skb;
1772 }
1773
1774 static inline struct sk_buff *netdev_alloc_skb_ip_align(struct net_device *dev,
1775 unsigned int length)
1776 {
1777 return __netdev_alloc_skb_ip_align(dev, length, GFP_ATOMIC);
1778 }
1779
1780 /*
1781 * __skb_alloc_page - allocate pages for ps-rx on a skb and preserve pfmemalloc data
1782 * @gfp_mask: alloc_pages_node mask. Set __GFP_NOMEMALLOC if not for network packet RX
1783 * @skb: skb to set pfmemalloc on if __GFP_MEMALLOC is used
1784 * @order: size of the allocation
1785 *
1786 * Allocate a new page.
1787 *
1788 * %NULL is returned if there is no free memory.
1789 */
1790 static inline struct page *__skb_alloc_pages(gfp_t gfp_mask,
1791 struct sk_buff *skb,
1792 unsigned int order)
1793 {
1794 struct page *page;
1795
1796 gfp_mask |= __GFP_COLD;
1797
1798 if (!(gfp_mask & __GFP_NOMEMALLOC))
1799 gfp_mask |= __GFP_MEMALLOC;
1800
1801 page = alloc_pages_node(NUMA_NO_NODE, gfp_mask, order);
1802 if (skb && page && page->pfmemalloc)
1803 skb->pfmemalloc = true;
1804
1805 return page;
1806 }
1807
1808 /**
1809 * __skb_alloc_page - allocate a page for ps-rx for a given skb and preserve pfmemalloc data
1810 * @gfp_mask: alloc_pages_node mask. Set __GFP_NOMEMALLOC if not for network packet RX
1811 * @skb: skb to set pfmemalloc on if __GFP_MEMALLOC is used
1812 *
1813 * Allocate a new page.
1814 *
1815 * %NULL is returned if there is no free memory.
1816 */
1817 static inline struct page *__skb_alloc_page(gfp_t gfp_mask,
1818 struct sk_buff *skb)
1819 {
1820 return __skb_alloc_pages(gfp_mask, skb, 0);
1821 }
1822
1823 /**
1824 * skb_propagate_pfmemalloc - Propagate pfmemalloc if skb is allocated after RX page
1825 * @page: The page that was allocated from skb_alloc_page
1826 * @skb: The skb that may need pfmemalloc set
1827 */
1828 static inline void skb_propagate_pfmemalloc(struct page *page,
1829 struct sk_buff *skb)
1830 {
1831 if (page && page->pfmemalloc)
1832 skb->pfmemalloc = true;
1833 }
1834
1835 /**
1836 * skb_frag_page - retrieve the page refered to by a paged fragment
1837 * @frag: the paged fragment
1838 *
1839 * Returns the &struct page associated with @frag.
1840 */
1841 static inline struct page *skb_frag_page(const skb_frag_t *frag)
1842 {
1843 return frag->page.p;
1844 }
1845
1846 /**
1847 * __skb_frag_ref - take an addition reference on a paged fragment.
1848 * @frag: the paged fragment
1849 *
1850 * Takes an additional reference on the paged fragment @frag.
1851 */
1852 static inline void __skb_frag_ref(skb_frag_t *frag)
1853 {
1854 get_page(skb_frag_page(frag));
1855 }
1856
1857 /**
1858 * skb_frag_ref - take an addition reference on a paged fragment of an skb.
1859 * @skb: the buffer
1860 * @f: the fragment offset.
1861 *
1862 * Takes an additional reference on the @f'th paged fragment of @skb.
1863 */
1864 static inline void skb_frag_ref(struct sk_buff *skb, int f)
1865 {
1866 __skb_frag_ref(&skb_shinfo(skb)->frags[f]);
1867 }
1868
1869 /**
1870 * __skb_frag_unref - release a reference on a paged fragment.
1871 * @frag: the paged fragment
1872 *
1873 * Releases a reference on the paged fragment @frag.
1874 */
1875 static inline void __skb_frag_unref(skb_frag_t *frag)
1876 {
1877 put_page(skb_frag_page(frag));
1878 }
1879
1880 /**
1881 * skb_frag_unref - release a reference on a paged fragment of an skb.
1882 * @skb: the buffer
1883 * @f: the fragment offset
1884 *
1885 * Releases a reference on the @f'th paged fragment of @skb.
1886 */
1887 static inline void skb_frag_unref(struct sk_buff *skb, int f)
1888 {
1889 __skb_frag_unref(&skb_shinfo(skb)->frags[f]);
1890 }
1891
1892 /**
1893 * skb_frag_address - gets the address of the data contained in a paged fragment
1894 * @frag: the paged fragment buffer
1895 *
1896 * Returns the address of the data within @frag. The page must already
1897 * be mapped.
1898 */
1899 static inline void *skb_frag_address(const skb_frag_t *frag)
1900 {
1901 return page_address(skb_frag_page(frag)) + frag->page_offset;
1902 }
1903
1904 /**
1905 * skb_frag_address_safe - gets the address of the data contained in a paged fragment
1906 * @frag: the paged fragment buffer
1907 *
1908 * Returns the address of the data within @frag. Checks that the page
1909 * is mapped and returns %NULL otherwise.
1910 */
1911 static inline void *skb_frag_address_safe(const skb_frag_t *frag)
1912 {
1913 void *ptr = page_address(skb_frag_page(frag));
1914 if (unlikely(!ptr))
1915 return NULL;
1916
1917 return ptr + frag->page_offset;
1918 }
1919
1920 /**
1921 * __skb_frag_set_page - sets the page contained in a paged fragment
1922 * @frag: the paged fragment
1923 * @page: the page to set
1924 *
1925 * Sets the fragment @frag to contain @page.
1926 */
1927 static inline void __skb_frag_set_page(skb_frag_t *frag, struct page *page)
1928 {
1929 frag->page.p = page;
1930 }
1931
1932 /**
1933 * skb_frag_set_page - sets the page contained in a paged fragment of an skb
1934 * @skb: the buffer
1935 * @f: the fragment offset
1936 * @page: the page to set
1937 *
1938 * Sets the @f'th fragment of @skb to contain @page.
1939 */
1940 static inline void skb_frag_set_page(struct sk_buff *skb, int f,
1941 struct page *page)
1942 {
1943 __skb_frag_set_page(&skb_shinfo(skb)->frags[f], page);
1944 }
1945
1946 /**
1947 * skb_frag_dma_map - maps a paged fragment via the DMA API
1948 * @dev: the device to map the fragment to
1949 * @frag: the paged fragment to map
1950 * @offset: the offset within the fragment (starting at the
1951 * fragment's own offset)
1952 * @size: the number of bytes to map
1953 * @dir: the direction of the mapping (%PCI_DMA_*)
1954 *
1955 * Maps the page associated with @frag to @device.
1956 */
1957 static inline dma_addr_t skb_frag_dma_map(struct device *dev,
1958 const skb_frag_t *frag,
1959 size_t offset, size_t size,
1960 enum dma_data_direction dir)
1961 {
1962 return dma_map_page(dev, skb_frag_page(frag),
1963 frag->page_offset + offset, size, dir);
1964 }
1965
1966 static inline struct sk_buff *pskb_copy(struct sk_buff *skb,
1967 gfp_t gfp_mask)
1968 {
1969 return __pskb_copy(skb, skb_headroom(skb), gfp_mask);
1970 }
1971
1972 /**
1973 * skb_clone_writable - is the header of a clone writable
1974 * @skb: buffer to check
1975 * @len: length up to which to write
1976 *
1977 * Returns true if modifying the header part of the cloned buffer
1978 * does not requires the data to be copied.
1979 */
1980 static inline int skb_clone_writable(const struct sk_buff *skb, unsigned int len)
1981 {
1982 return !skb_header_cloned(skb) &&
1983 skb_headroom(skb) + len <= skb->hdr_len;
1984 }
1985
1986 static inline int __skb_cow(struct sk_buff *skb, unsigned int headroom,
1987 int cloned)
1988 {
1989 int delta = 0;
1990
1991 if (headroom > skb_headroom(skb))
1992 delta = headroom - skb_headroom(skb);
1993
1994 if (delta || cloned)
1995 return pskb_expand_head(skb, ALIGN(delta, NET_SKB_PAD), 0,
1996 GFP_ATOMIC);
1997 return 0;
1998 }
1999
2000 /**
2001 * skb_cow - copy header of skb when it is required
2002 * @skb: buffer to cow
2003 * @headroom: needed headroom
2004 *
2005 * If the skb passed lacks sufficient headroom or its data part
2006 * is shared, data is reallocated. If reallocation fails, an error
2007 * is returned and original skb is not changed.
2008 *
2009 * The result is skb with writable area skb->head...skb->tail
2010 * and at least @headroom of space at head.
2011 */
2012 static inline int skb_cow(struct sk_buff *skb, unsigned int headroom)
2013 {
2014 return __skb_cow(skb, headroom, skb_cloned(skb));
2015 }
2016
2017 /**
2018 * skb_cow_head - skb_cow but only making the head writable
2019 * @skb: buffer to cow
2020 * @headroom: needed headroom
2021 *
2022 * This function is identical to skb_cow except that we replace the
2023 * skb_cloned check by skb_header_cloned. It should be used when
2024 * you only need to push on some header and do not need to modify
2025 * the data.
2026 */
2027 static inline int skb_cow_head(struct sk_buff *skb, unsigned int headroom)
2028 {
2029 return __skb_cow(skb, headroom, skb_header_cloned(skb));
2030 }
2031
2032 /**
2033 * skb_padto - pad an skbuff up to a minimal size
2034 * @skb: buffer to pad
2035 * @len: minimal length
2036 *
2037 * Pads up a buffer to ensure the trailing bytes exist and are
2038 * blanked. If the buffer already contains sufficient data it
2039 * is untouched. Otherwise it is extended. Returns zero on
2040 * success. The skb is freed on error.
2041 */
2042
2043 static inline int skb_padto(struct sk_buff *skb, unsigned int len)
2044 {
2045 unsigned int size = skb->len;
2046 if (likely(size >= len))
2047 return 0;
2048 return skb_pad(skb, len - size);
2049 }
2050
2051 static inline int skb_add_data(struct sk_buff *skb,
2052 char __user *from, int copy)
2053 {
2054 const int off = skb->len;
2055
2056 if (skb->ip_summed == CHECKSUM_NONE) {
2057 int err = 0;
2058 __wsum csum = csum_and_copy_from_user(from, skb_put(skb, copy),
2059 copy, 0, &err);
2060 if (!err) {
2061 skb->csum = csum_block_add(skb->csum, csum, off);
2062 return 0;
2063 }
2064 } else if (!copy_from_user(skb_put(skb, copy), from, copy))
2065 return 0;
2066
2067 __skb_trim(skb, off);
2068 return -EFAULT;
2069 }
2070
2071 static inline bool skb_can_coalesce(struct sk_buff *skb, int i,
2072 const struct page *page, int off)
2073 {
2074 if (i) {
2075 const struct skb_frag_struct *frag = &skb_shinfo(skb)->frags[i - 1];
2076
2077 return page == skb_frag_page(frag) &&
2078 off == frag->page_offset + skb_frag_size(frag);
2079 }
2080 return false;
2081 }
2082
2083 static inline int __skb_linearize(struct sk_buff *skb)
2084 {
2085 return __pskb_pull_tail(skb, skb->data_len) ? 0 : -ENOMEM;
2086 }
2087
2088 /**
2089 * skb_linearize - convert paged skb to linear one
2090 * @skb: buffer to linarize
2091 *
2092 * If there is no free memory -ENOMEM is returned, otherwise zero
2093 * is returned and the old skb data released.
2094 */
2095 static inline int skb_linearize(struct sk_buff *skb)
2096 {
2097 return skb_is_nonlinear(skb) ? __skb_linearize(skb) : 0;
2098 }
2099
2100 /**
2101 * skb_linearize_cow - make sure skb is linear and writable
2102 * @skb: buffer to process
2103 *
2104 * If there is no free memory -ENOMEM is returned, otherwise zero
2105 * is returned and the old skb data released.
2106 */
2107 static inline int skb_linearize_cow(struct sk_buff *skb)
2108 {
2109 return skb_is_nonlinear(skb) || skb_cloned(skb) ?
2110 __skb_linearize(skb) : 0;
2111 }
2112
2113 /**
2114 * skb_postpull_rcsum - update checksum for received skb after pull
2115 * @skb: buffer to update
2116 * @start: start of data before pull
2117 * @len: length of data pulled
2118 *
2119 * After doing a pull on a received packet, you need to call this to
2120 * update the CHECKSUM_COMPLETE checksum, or set ip_summed to
2121 * CHECKSUM_NONE so that it can be recomputed from scratch.
2122 */
2123
2124 static inline void skb_postpull_rcsum(struct sk_buff *skb,
2125 const void *start, unsigned int len)
2126 {
2127 if (skb->ip_summed == CHECKSUM_COMPLETE)
2128 skb->csum = csum_sub(skb->csum, csum_partial(start, len, 0));
2129 }
2130
2131 unsigned char *skb_pull_rcsum(struct sk_buff *skb, unsigned int len);
2132
2133 /**
2134 * pskb_trim_rcsum - trim received skb and update checksum
2135 * @skb: buffer to trim
2136 * @len: new length
2137 *
2138 * This is exactly the same as pskb_trim except that it ensures the
2139 * checksum of received packets are still valid after the operation.
2140 */
2141
2142 static inline int pskb_trim_rcsum(struct sk_buff *skb, unsigned int len)
2143 {
2144 if (likely(len >= skb->len))
2145 return 0;
2146 if (skb->ip_summed == CHECKSUM_COMPLETE)
2147 skb->ip_summed = CHECKSUM_NONE;
2148 return __pskb_trim(skb, len);
2149 }
2150
2151 #define skb_queue_walk(queue, skb) \
2152 for (skb = (queue)->next; \
2153 skb != (struct sk_buff *)(queue); \
2154 skb = skb->next)
2155
2156 #define skb_queue_walk_safe(queue, skb, tmp) \
2157 for (skb = (queue)->next, tmp = skb->next; \
2158 skb != (struct sk_buff *)(queue); \
2159 skb = tmp, tmp = skb->next)
2160
2161 #define skb_queue_walk_from(queue, skb) \
2162 for (; skb != (struct sk_buff *)(queue); \
2163 skb = skb->next)
2164
2165 #define skb_queue_walk_from_safe(queue, skb, tmp) \
2166 for (tmp = skb->next; \
2167 skb != (struct sk_buff *)(queue); \
2168 skb = tmp, tmp = skb->next)
2169
2170 #define skb_queue_reverse_walk(queue, skb) \
2171 for (skb = (queue)->prev; \
2172 skb != (struct sk_buff *)(queue); \
2173 skb = skb->prev)
2174
2175 #define skb_queue_reverse_walk_safe(queue, skb, tmp) \
2176 for (skb = (queue)->prev, tmp = skb->prev; \
2177 skb != (struct sk_buff *)(queue); \
2178 skb = tmp, tmp = skb->prev)
2179
2180 #define skb_queue_reverse_walk_from_safe(queue, skb, tmp) \
2181 for (tmp = skb->prev; \
2182 skb != (struct sk_buff *)(queue); \
2183 skb = tmp, tmp = skb->prev)
2184
2185 static inline bool skb_has_frag_list(const struct sk_buff *skb)
2186 {
2187 return skb_shinfo(skb)->frag_list != NULL;
2188 }
2189
2190 static inline void skb_frag_list_init(struct sk_buff *skb)
2191 {
2192 skb_shinfo(skb)->frag_list = NULL;
2193 }
2194
2195 static inline void skb_frag_add_head(struct sk_buff *skb, struct sk_buff *frag)
2196 {
2197 frag->next = skb_shinfo(skb)->frag_list;
2198 skb_shinfo(skb)->frag_list = frag;
2199 }
2200
2201 #define skb_walk_frags(skb, iter) \
2202 for (iter = skb_shinfo(skb)->frag_list; iter; iter = iter->next)
2203
2204 extern struct sk_buff *__skb_recv_datagram(struct sock *sk, unsigned flags,
2205 int *peeked, int *off, int *err);
2206 extern struct sk_buff *skb_recv_datagram(struct sock *sk, unsigned flags,
2207 int noblock, int *err);
2208 extern unsigned int datagram_poll(struct file *file, struct socket *sock,
2209 struct poll_table_struct *wait);
2210 extern int skb_copy_datagram_iovec(const struct sk_buff *from,
2211 int offset, struct iovec *to,
2212 int size);
2213 extern int skb_copy_and_csum_datagram_iovec(struct sk_buff *skb,
2214 int hlen,
2215 struct iovec *iov);
2216 extern int skb_copy_datagram_from_iovec(struct sk_buff *skb,
2217 int offset,
2218 const struct iovec *from,
2219 int from_offset,
2220 int len);
2221 extern int skb_copy_datagram_const_iovec(const struct sk_buff *from,
2222 int offset,
2223 const struct iovec *to,
2224 int to_offset,
2225 int size);
2226 extern void skb_free_datagram(struct sock *sk, struct sk_buff *skb);
2227 extern void skb_free_datagram_locked(struct sock *sk,
2228 struct sk_buff *skb);
2229 extern int skb_kill_datagram(struct sock *sk, struct sk_buff *skb,
2230 unsigned int flags);
2231 extern __wsum skb_checksum(const struct sk_buff *skb, int offset,
2232 int len, __wsum csum);
2233 extern int skb_copy_bits(const struct sk_buff *skb, int offset,
2234 void *to, int len);
2235 extern int skb_store_bits(struct sk_buff *skb, int offset,
2236 const void *from, int len);
2237 extern __wsum skb_copy_and_csum_bits(const struct sk_buff *skb,
2238 int offset, u8 *to, int len,
2239 __wsum csum);
2240 extern int skb_splice_bits(struct sk_buff *skb,
2241 unsigned int offset,
2242 struct pipe_inode_info *pipe,
2243 unsigned int len,
2244 unsigned int flags);
2245 extern void skb_copy_and_csum_dev(const struct sk_buff *skb, u8 *to);
2246 extern void skb_split(struct sk_buff *skb,
2247 struct sk_buff *skb1, const u32 len);
2248 extern int skb_shift(struct sk_buff *tgt, struct sk_buff *skb,
2249 int shiftlen);
2250
2251 extern struct sk_buff *skb_segment(struct sk_buff *skb,
2252 netdev_features_t features);
2253
2254 static inline void *skb_header_pointer(const struct sk_buff *skb, int offset,
2255 int len, void *buffer)
2256 {
2257 int hlen = skb_headlen(skb);
2258
2259 if (hlen - offset >= len)
2260 return skb->data + offset;
2261
2262 if (skb_copy_bits(skb, offset, buffer, len) < 0)
2263 return NULL;
2264
2265 return buffer;
2266 }
2267
2268 static inline void skb_copy_from_linear_data(const struct sk_buff *skb,
2269 void *to,
2270 const unsigned int len)
2271 {
2272 memcpy(to, skb->data, len);
2273 }
2274
2275 static inline void skb_copy_from_linear_data_offset(const struct sk_buff *skb,
2276 const int offset, void *to,
2277 const unsigned int len)
2278 {
2279 memcpy(to, skb->data + offset, len);
2280 }
2281
2282 static inline void skb_copy_to_linear_data(struct sk_buff *skb,
2283 const void *from,
2284 const unsigned int len)
2285 {
2286 memcpy(skb->data, from, len);
2287 }
2288
2289 static inline void skb_copy_to_linear_data_offset(struct sk_buff *skb,
2290 const int offset,
2291 const void *from,
2292 const unsigned int len)
2293 {
2294 memcpy(skb->data + offset, from, len);
2295 }
2296
2297 extern void skb_init(void);
2298
2299 static inline ktime_t skb_get_ktime(const struct sk_buff *skb)
2300 {
2301 return skb->tstamp;
2302 }
2303
2304 /**
2305 * skb_get_timestamp - get timestamp from a skb
2306 * @skb: skb to get stamp from
2307 * @stamp: pointer to struct timeval to store stamp in
2308 *
2309 * Timestamps are stored in the skb as offsets to a base timestamp.
2310 * This function converts the offset back to a struct timeval and stores
2311 * it in stamp.
2312 */
2313 static inline void skb_get_timestamp(const struct sk_buff *skb,
2314 struct timeval *stamp)
2315 {
2316 *stamp = ktime_to_timeval(skb->tstamp);
2317 }
2318
2319 static inline void skb_get_timestampns(const struct sk_buff *skb,
2320 struct timespec *stamp)
2321 {
2322 *stamp = ktime_to_timespec(skb->tstamp);
2323 }
2324
2325 static inline void __net_timestamp(struct sk_buff *skb)
2326 {
2327 skb->tstamp = ktime_get_real();
2328 }
2329
2330 static inline ktime_t net_timedelta(ktime_t t)
2331 {
2332 return ktime_sub(ktime_get_real(), t);
2333 }
2334
2335 static inline ktime_t net_invalid_timestamp(void)
2336 {
2337 return ktime_set(0, 0);
2338 }
2339
2340 extern void skb_timestamping_init(void);
2341
2342 #ifdef CONFIG_NETWORK_PHY_TIMESTAMPING
2343
2344 extern void skb_clone_tx_timestamp(struct sk_buff *skb);
2345 extern bool skb_defer_rx_timestamp(struct sk_buff *skb);
2346
2347 #else /* CONFIG_NETWORK_PHY_TIMESTAMPING */
2348
2349 static inline void skb_clone_tx_timestamp(struct sk_buff *skb)
2350 {
2351 }
2352
2353 static inline bool skb_defer_rx_timestamp(struct sk_buff *skb)
2354 {
2355 return false;
2356 }
2357
2358 #endif /* !CONFIG_NETWORK_PHY_TIMESTAMPING */
2359
2360 /**
2361 * skb_complete_tx_timestamp() - deliver cloned skb with tx timestamps
2362 *
2363 * PHY drivers may accept clones of transmitted packets for
2364 * timestamping via their phy_driver.txtstamp method. These drivers
2365 * must call this function to return the skb back to the stack, with
2366 * or without a timestamp.
2367 *
2368 * @skb: clone of the the original outgoing packet
2369 * @hwtstamps: hardware time stamps, may be NULL if not available
2370 *
2371 */
2372 void skb_complete_tx_timestamp(struct sk_buff *skb,
2373 struct skb_shared_hwtstamps *hwtstamps);
2374
2375 /**
2376 * skb_tstamp_tx - queue clone of skb with send time stamps
2377 * @orig_skb: the original outgoing packet
2378 * @hwtstamps: hardware time stamps, may be NULL if not available
2379 *
2380 * If the skb has a socket associated, then this function clones the
2381 * skb (thus sharing the actual data and optional structures), stores
2382 * the optional hardware time stamping information (if non NULL) or
2383 * generates a software time stamp (otherwise), then queues the clone
2384 * to the error queue of the socket. Errors are silently ignored.
2385 */
2386 extern void skb_tstamp_tx(struct sk_buff *orig_skb,
2387 struct skb_shared_hwtstamps *hwtstamps);
2388
2389 static inline void sw_tx_timestamp(struct sk_buff *skb)
2390 {
2391 if (skb_shinfo(skb)->tx_flags & SKBTX_SW_TSTAMP &&
2392 !(skb_shinfo(skb)->tx_flags & SKBTX_IN_PROGRESS))
2393 skb_tstamp_tx(skb, NULL);
2394 }
2395
2396 /**
2397 * skb_tx_timestamp() - Driver hook for transmit timestamping
2398 *
2399 * Ethernet MAC Drivers should call this function in their hard_xmit()
2400 * function immediately before giving the sk_buff to the MAC hardware.
2401 *
2402 * @skb: A socket buffer.
2403 */
2404 static inline void skb_tx_timestamp(struct sk_buff *skb)
2405 {
2406 skb_clone_tx_timestamp(skb);
2407 sw_tx_timestamp(skb);
2408 }
2409
2410 /**
2411 * skb_complete_wifi_ack - deliver skb with wifi status
2412 *
2413 * @skb: the original outgoing packet
2414 * @acked: ack status
2415 *
2416 */
2417 void skb_complete_wifi_ack(struct sk_buff *skb, bool acked);
2418
2419 extern __sum16 __skb_checksum_complete_head(struct sk_buff *skb, int len);
2420 extern __sum16 __skb_checksum_complete(struct sk_buff *skb);
2421
2422 static inline int skb_csum_unnecessary(const struct sk_buff *skb)
2423 {
2424 return skb->ip_summed & CHECKSUM_UNNECESSARY;
2425 }
2426
2427 /**
2428 * skb_checksum_complete - Calculate checksum of an entire packet
2429 * @skb: packet to process
2430 *
2431 * This function calculates the checksum over the entire packet plus
2432 * the value of skb->csum. The latter can be used to supply the
2433 * checksum of a pseudo header as used by TCP/UDP. It returns the
2434 * checksum.
2435 *
2436 * For protocols that contain complete checksums such as ICMP/TCP/UDP,
2437 * this function can be used to verify that checksum on received
2438 * packets. In that case the function should return zero if the
2439 * checksum is correct. In particular, this function will return zero
2440 * if skb->ip_summed is CHECKSUM_UNNECESSARY which indicates that the
2441 * hardware has already verified the correctness of the checksum.
2442 */
2443 static inline __sum16 skb_checksum_complete(struct sk_buff *skb)
2444 {
2445 return skb_csum_unnecessary(skb) ?
2446 0 : __skb_checksum_complete(skb);
2447 }
2448
2449 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
2450 extern void nf_conntrack_destroy(struct nf_conntrack *nfct);
2451 static inline void nf_conntrack_put(struct nf_conntrack *nfct)
2452 {
2453 if (nfct && atomic_dec_and_test(&nfct->use))
2454 nf_conntrack_destroy(nfct);
2455 }
2456 static inline void nf_conntrack_get(struct nf_conntrack *nfct)
2457 {
2458 if (nfct)
2459 atomic_inc(&nfct->use);
2460 }
2461 #endif
2462 #ifdef NET_SKBUFF_NF_DEFRAG_NEEDED
2463 static inline void nf_conntrack_get_reasm(struct sk_buff *skb)
2464 {
2465 if (skb)
2466 atomic_inc(&skb->users);
2467 }
2468 static inline void nf_conntrack_put_reasm(struct sk_buff *skb)
2469 {
2470 if (skb)
2471 kfree_skb(skb);
2472 }
2473 #endif
2474 #ifdef CONFIG_BRIDGE_NETFILTER
2475 static inline void nf_bridge_put(struct nf_bridge_info *nf_bridge)
2476 {
2477 if (nf_bridge && atomic_dec_and_test(&nf_bridge->use))
2478 kfree(nf_bridge);
2479 }
2480 static inline void nf_bridge_get(struct nf_bridge_info *nf_bridge)
2481 {
2482 if (nf_bridge)
2483 atomic_inc(&nf_bridge->use);
2484 }
2485 #endif /* CONFIG_BRIDGE_NETFILTER */
2486 static inline void nf_reset(struct sk_buff *skb)
2487 {
2488 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
2489 nf_conntrack_put(skb->nfct);
2490 skb->nfct = NULL;
2491 #endif
2492 #ifdef NET_SKBUFF_NF_DEFRAG_NEEDED
2493 nf_conntrack_put_reasm(skb->nfct_reasm);
2494 skb->nfct_reasm = NULL;
2495 #endif
2496 #ifdef CONFIG_BRIDGE_NETFILTER
2497 nf_bridge_put(skb->nf_bridge);
2498 skb->nf_bridge = NULL;
2499 #endif
2500 }
2501
2502 /* Note: This doesn't put any conntrack and bridge info in dst. */
2503 static inline void __nf_copy(struct sk_buff *dst, const struct sk_buff *src)
2504 {
2505 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
2506 dst->nfct = src->nfct;
2507 nf_conntrack_get(src->nfct);
2508 dst->nfctinfo = src->nfctinfo;
2509 #endif
2510 #ifdef NET_SKBUFF_NF_DEFRAG_NEEDED
2511 dst->nfct_reasm = src->nfct_reasm;
2512 nf_conntrack_get_reasm(src->nfct_reasm);
2513 #endif
2514 #ifdef CONFIG_BRIDGE_NETFILTER
2515 dst->nf_bridge = src->nf_bridge;
2516 nf_bridge_get(src->nf_bridge);
2517 #endif
2518 }
2519
2520 static inline void nf_copy(struct sk_buff *dst, const struct sk_buff *src)
2521 {
2522 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
2523 nf_conntrack_put(dst->nfct);
2524 #endif
2525 #ifdef NET_SKBUFF_NF_DEFRAG_NEEDED
2526 nf_conntrack_put_reasm(dst->nfct_reasm);
2527 #endif
2528 #ifdef CONFIG_BRIDGE_NETFILTER
2529 nf_bridge_put(dst->nf_bridge);
2530 #endif
2531 __nf_copy(dst, src);
2532 }
2533
2534 #ifdef CONFIG_NETWORK_SECMARK
2535 static inline void skb_copy_secmark(struct sk_buff *to, const struct sk_buff *from)
2536 {
2537 to->secmark = from->secmark;
2538 }
2539
2540 static inline void skb_init_secmark(struct sk_buff *skb)
2541 {
2542 skb->secmark = 0;
2543 }
2544 #else
2545 static inline void skb_copy_secmark(struct sk_buff *to, const struct sk_buff *from)
2546 { }
2547
2548 static inline void skb_init_secmark(struct sk_buff *skb)
2549 { }
2550 #endif
2551
2552 static inline void skb_set_queue_mapping(struct sk_buff *skb, u16 queue_mapping)
2553 {
2554 skb->queue_mapping = queue_mapping;
2555 }
2556
2557 static inline u16 skb_get_queue_mapping(const struct sk_buff *skb)
2558 {
2559 return skb->queue_mapping;
2560 }
2561
2562 static inline void skb_copy_queue_mapping(struct sk_buff *to, const struct sk_buff *from)
2563 {
2564 to->queue_mapping = from->queue_mapping;
2565 }
2566
2567 static inline void skb_record_rx_queue(struct sk_buff *skb, u16 rx_queue)
2568 {
2569 skb->queue_mapping = rx_queue + 1;
2570 }
2571
2572 static inline u16 skb_get_rx_queue(const struct sk_buff *skb)
2573 {
2574 return skb->queue_mapping - 1;
2575 }
2576
2577 static inline bool skb_rx_queue_recorded(const struct sk_buff *skb)
2578 {
2579 return skb->queue_mapping != 0;
2580 }
2581
2582 extern u16 __skb_tx_hash(const struct net_device *dev,
2583 const struct sk_buff *skb,
2584 unsigned int num_tx_queues);
2585
2586 #ifdef CONFIG_XFRM
2587 static inline struct sec_path *skb_sec_path(struct sk_buff *skb)
2588 {
2589 return skb->sp;
2590 }
2591 #else
2592 static inline struct sec_path *skb_sec_path(struct sk_buff *skb)
2593 {
2594 return NULL;
2595 }
2596 #endif
2597
2598 static inline bool skb_is_gso(const struct sk_buff *skb)
2599 {
2600 return skb_shinfo(skb)->gso_size;
2601 }
2602
2603 static inline bool skb_is_gso_v6(const struct sk_buff *skb)
2604 {
2605 return skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6;
2606 }
2607
2608 extern void __skb_warn_lro_forwarding(const struct sk_buff *skb);
2609
2610 static inline bool skb_warn_if_lro(const struct sk_buff *skb)
2611 {
2612 /* LRO sets gso_size but not gso_type, whereas if GSO is really
2613 * wanted then gso_type will be set. */
2614 const struct skb_shared_info *shinfo = skb_shinfo(skb);
2615
2616 if (skb_is_nonlinear(skb) && shinfo->gso_size != 0 &&
2617 unlikely(shinfo->gso_type == 0)) {
2618 __skb_warn_lro_forwarding(skb);
2619 return true;
2620 }
2621 return false;
2622 }
2623
2624 static inline void skb_forward_csum(struct sk_buff *skb)
2625 {
2626 /* Unfortunately we don't support this one. Any brave souls? */
2627 if (skb->ip_summed == CHECKSUM_COMPLETE)
2628 skb->ip_summed = CHECKSUM_NONE;
2629 }
2630
2631 /**
2632 * skb_checksum_none_assert - make sure skb ip_summed is CHECKSUM_NONE
2633 * @skb: skb to check
2634 *
2635 * fresh skbs have their ip_summed set to CHECKSUM_NONE.
2636 * Instead of forcing ip_summed to CHECKSUM_NONE, we can
2637 * use this helper, to document places where we make this assertion.
2638 */
2639 static inline void skb_checksum_none_assert(const struct sk_buff *skb)
2640 {
2641 #ifdef DEBUG
2642 BUG_ON(skb->ip_summed != CHECKSUM_NONE);
2643 #endif
2644 }
2645
2646 bool skb_partial_csum_set(struct sk_buff *skb, u16 start, u16 off);
2647
2648 static inline bool skb_is_recycleable(const struct sk_buff *skb, int skb_size)
2649 {
2650 if (irqs_disabled())
2651 return false;
2652
2653 if (skb_shinfo(skb)->tx_flags & SKBTX_DEV_ZEROCOPY)
2654 return false;
2655
2656 if (skb_is_nonlinear(skb) || skb->fclone != SKB_FCLONE_UNAVAILABLE)
2657 return false;
2658
2659 skb_size = SKB_DATA_ALIGN(skb_size + NET_SKB_PAD);
2660 if (skb_end_offset(skb) < skb_size)
2661 return false;
2662
2663 if (skb_shared(skb) || skb_cloned(skb))
2664 return false;
2665
2666 return true;
2667 }
2668
2669 /**
2670 * skb_head_is_locked - Determine if the skb->head is locked down
2671 * @skb: skb to check
2672 *
2673 * The head on skbs build around a head frag can be removed if they are
2674 * not cloned. This function returns true if the skb head is locked down
2675 * due to either being allocated via kmalloc, or by being a clone with
2676 * multiple references to the head.
2677 */
2678 static inline bool skb_head_is_locked(const struct sk_buff *skb)
2679 {
2680 return !skb->head_frag || skb_cloned(skb);
2681 }
2682 #endif /* __KERNEL__ */
2683 #endif /* _LINUX_SKBUFF_H */