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#include <linux/rbtree.h>
24#include <linux/socket.h>
25
26#include <linux/atomic.h>
27#include <asm/types.h>
28#include <linux/spinlock.h>
29#include <linux/net.h>
30#include <linux/textsearch.h>
31#include <net/checksum.h>
32#include <linux/rcupdate.h>
33#include <linux/hrtimer.h>
34#include <linux/dma-mapping.h>
35#include <linux/netdev_features.h>
36#include <linux/sched.h>
37#include <linux/sched/clock.h>
38#include <net/flow_dissector.h>
39#include <linux/splice.h>
40#include <linux/in6.h>
41#include <linux/if_packet.h>
42#include <net/flow.h>
43
44/* The interface for checksum offload between the stack and networking drivers
45 * is as follows...
46 *
47 * A. IP checksum related features
48 *
49 * Drivers advertise checksum offload capabilities in the features of a device.
50 * From the stack's point of view these are capabilities offered by the driver,
51 * a driver typically only advertises features that it is capable of offloading
52 * to its device.
53 *
54 * The checksum related features are:
55 *
56 * NETIF_F_HW_CSUM - The driver (or its device) is able to compute one
57 * IP (one's complement) checksum for any combination
58 * of protocols or protocol layering. The checksum is
59 * computed and set in a packet per the CHECKSUM_PARTIAL
60 * interface (see below).
61 *
62 * NETIF_F_IP_CSUM - Driver (device) is only able to checksum plain
63 * TCP or UDP packets over IPv4. These are specifically
64 * unencapsulated packets of the form IPv4|TCP or
65 * IPv4|UDP where the Protocol field in the IPv4 header
66 * is TCP or UDP. The IPv4 header may contain IP options
67 * This feature cannot be set in features for a device
68 * with NETIF_F_HW_CSUM also set. This feature is being
69 * DEPRECATED (see below).
70 *
71 * NETIF_F_IPV6_CSUM - Driver (device) is only able to checksum plain
72 * TCP or UDP packets over IPv6. These are specifically
73 * unencapsulated packets of the form IPv6|TCP or
74 * IPv4|UDP where the Next Header field in the IPv6
75 * header is either TCP or UDP. IPv6 extension headers
76 * are not supported with this feature. This feature
77 * cannot be set in features for a device with
78 * NETIF_F_HW_CSUM also set. This feature is being
79 * DEPRECATED (see below).
80 *
81 * NETIF_F_RXCSUM - Driver (device) performs receive checksum offload.
82 * This flag is used only used to disable the RX checksum
83 * feature for a device. The stack will accept receive
84 * checksum indication in packets received on a device
85 * regardless of whether NETIF_F_RXCSUM is set.
86 *
87 * B. Checksumming of received packets by device. Indication of checksum
88 * verification is in set skb->ip_summed. Possible values are:
89 *
90 * CHECKSUM_NONE:
91 *
92 * Device did not checksum this packet e.g. due to lack of capabilities.
93 * The packet contains full (though not verified) checksum in packet but
94 * not in skb->csum. Thus, skb->csum is undefined in this case.
95 *
96 * CHECKSUM_UNNECESSARY:
97 *
98 * The hardware you're dealing with doesn't calculate the full checksum
99 * (as in CHECKSUM_COMPLETE), but it does parse headers and verify checksums
100 * for specific protocols. For such packets it will set CHECKSUM_UNNECESSARY
101 * if their checksums are okay. skb->csum is still undefined in this case
102 * though. A driver or device must never modify the checksum field in the
103 * packet even if checksum is verified.
104 *
105 * CHECKSUM_UNNECESSARY is applicable to following protocols:
106 * TCP: IPv6 and IPv4.
107 * UDP: IPv4 and IPv6. A device may apply CHECKSUM_UNNECESSARY to a
108 * zero UDP checksum for either IPv4 or IPv6, the networking stack
109 * may perform further validation in this case.
110 * GRE: only if the checksum is present in the header.
111 * SCTP: indicates the CRC in SCTP header has been validated.
112 *
113 * skb->csum_level indicates the number of consecutive checksums found in
114 * the packet minus one that have been verified as CHECKSUM_UNNECESSARY.
115 * For instance if a device receives an IPv6->UDP->GRE->IPv4->TCP packet
116 * and a device is able to verify the checksums for UDP (possibly zero),
117 * GRE (checksum flag is set), and TCP-- skb->csum_level would be set to
118 * two. If the device were only able to verify the UDP checksum and not
119 * GRE, either because it doesn't support GRE checksum of because GRE
120 * checksum is bad, skb->csum_level would be set to zero (TCP checksum is
121 * not considered in this case).
122 *
123 * CHECKSUM_COMPLETE:
124 *
125 * This is the most generic way. The device supplied checksum of the _whole_
126 * packet as seen by netif_rx() and fills out in skb->csum. Meaning, the
127 * hardware doesn't need to parse L3/L4 headers to implement this.
128 *
129 * Note: Even if device supports only some protocols, but is able to produce
130 * skb->csum, it MUST use CHECKSUM_COMPLETE, not CHECKSUM_UNNECESSARY.
131 *
132 * CHECKSUM_PARTIAL:
133 *
134 * A checksum is set up to be offloaded to a device as described in the
135 * output description for CHECKSUM_PARTIAL. This may occur on a packet
136 * received directly from another Linux OS, e.g., a virtualized Linux kernel
137 * on the same host, or it may be set in the input path in GRO or remote
138 * checksum offload. For the purposes of checksum verification, the checksum
139 * referred to by skb->csum_start + skb->csum_offset and any preceding
140 * checksums in the packet are considered verified. Any checksums in the
141 * packet that are after the checksum being offloaded are not considered to
142 * be verified.
143 *
144 * C. Checksumming on transmit for non-GSO. The stack requests checksum offload
145 * in the skb->ip_summed for a packet. Values are:
146 *
147 * CHECKSUM_PARTIAL:
148 *
149 * The driver is required to checksum the packet as seen by hard_start_xmit()
150 * from skb->csum_start up to the end, and to record/write the checksum at
151 * offset skb->csum_start + skb->csum_offset. A driver may verify that the
152 * csum_start and csum_offset values are valid values given the length and
153 * offset of the packet, however they should not attempt to validate that the
154 * checksum refers to a legitimate transport layer checksum-- it is the
155 * purview of the stack to validate that csum_start and csum_offset are set
156 * correctly.
157 *
158 * When the stack requests checksum offload for a packet, the driver MUST
159 * ensure that the checksum is set correctly. A driver can either offload the
160 * checksum calculation to the device, or call skb_checksum_help (in the case
161 * that the device does not support offload for a particular checksum).
162 *
163 * NETIF_F_IP_CSUM and NETIF_F_IPV6_CSUM are being deprecated in favor of
164 * NETIF_F_HW_CSUM. New devices should use NETIF_F_HW_CSUM to indicate
165 * checksum offload capability. If a device has limited checksum capabilities
166 * (for instance can only perform NETIF_F_IP_CSUM or NETIF_F_IPV6_CSUM as
167 * described above) a helper function can be called to resolve
168 * CHECKSUM_PARTIAL. The helper functions are skb_csum_off_chk*. The helper
169 * function takes a spec argument that describes the protocol layer that is
170 * supported for checksum offload and can be called for each packet. If a
171 * packet does not match the specification for offload, skb_checksum_help
172 * is called to resolve the checksum.
173 *
174 * CHECKSUM_NONE:
175 *
176 * The skb was already checksummed by the protocol, or a checksum is not
177 * required.
178 *
179 * CHECKSUM_UNNECESSARY:
180 *
181 * This has the same meaning on as CHECKSUM_NONE for checksum offload on
182 * output.
183 *
184 * CHECKSUM_COMPLETE:
185 * Not used in checksum output. If a driver observes a packet with this value
186 * set in skbuff, if should treat as CHECKSUM_NONE being set.
187 *
188 * D. Non-IP checksum (CRC) offloads
189 *
190 * NETIF_F_SCTP_CRC - This feature indicates that a device is capable of
191 * offloading the SCTP CRC in a packet. To perform this offload the stack
192 * will set ip_summed to CHECKSUM_PARTIAL and set csum_start and csum_offset
193 * accordingly. Note the there is no indication in the skbuff that the
194 * CHECKSUM_PARTIAL refers to an SCTP checksum, a driver that supports
195 * both IP checksum offload and SCTP CRC offload must verify which offload
196 * is configured for a packet presumably by inspecting packet headers.
197 *
198 * NETIF_F_FCOE_CRC - This feature indicates that a device is capable of
199 * offloading the FCOE CRC in a packet. To perform this offload the stack
200 * will set ip_summed to CHECKSUM_PARTIAL and set csum_start and csum_offset
201 * accordingly. Note the there is no indication in the skbuff that the
202 * CHECKSUM_PARTIAL refers to an FCOE checksum, a driver that supports
203 * both IP checksum offload and FCOE CRC offload must verify which offload
204 * is configured for a packet presumably by inspecting packet headers.
205 *
206 * E. Checksumming on output with GSO.
207 *
208 * In the case of a GSO packet (skb_is_gso(skb) is true), checksum offload
209 * is implied by the SKB_GSO_* flags in gso_type. Most obviously, if the
210 * gso_type is SKB_GSO_TCPV4 or SKB_GSO_TCPV6, TCP checksum offload as
211 * part of the GSO operation is implied. If a checksum is being offloaded
212 * with GSO then ip_summed is CHECKSUM_PARTIAL, csum_start and csum_offset
213 * are set to refer to the outermost checksum being offload (two offloaded
214 * checksums are possible with UDP encapsulation).
215 */
216
217/* Don't change this without changing skb_csum_unnecessary! */
218#define CHECKSUM_NONE 0
219#define CHECKSUM_UNNECESSARY 1
220#define CHECKSUM_COMPLETE 2
221#define CHECKSUM_PARTIAL 3
222
223/* Maximum value in skb->csum_level */
224#define SKB_MAX_CSUM_LEVEL 3
225
226#define SKB_DATA_ALIGN(X) ALIGN(X, SMP_CACHE_BYTES)
227#define SKB_WITH_OVERHEAD(X) \
228 ((X) - SKB_DATA_ALIGN(sizeof(struct skb_shared_info)))
229#define SKB_MAX_ORDER(X, ORDER) \
230 SKB_WITH_OVERHEAD((PAGE_SIZE << (ORDER)) - (X))
231#define SKB_MAX_HEAD(X) (SKB_MAX_ORDER((X), 0))
232#define SKB_MAX_ALLOC (SKB_MAX_ORDER(0, 2))
233
234/* return minimum truesize of one skb containing X bytes of data */
235#define SKB_TRUESIZE(X) ((X) + \
236 SKB_DATA_ALIGN(sizeof(struct sk_buff)) + \
237 SKB_DATA_ALIGN(sizeof(struct skb_shared_info)))
238
239struct net_device;
240struct scatterlist;
241struct pipe_inode_info;
242struct iov_iter;
243struct napi_struct;
244
245#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
246struct nf_conntrack {
247 atomic_t use;
248};
249#endif
250
251#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
252struct nf_bridge_info {
253 atomic_t use;
254 enum {
255 BRNF_PROTO_UNCHANGED,
256 BRNF_PROTO_8021Q,
257 BRNF_PROTO_PPPOE
258 } orig_proto:8;
259 u8 pkt_otherhost:1;
260 u8 in_prerouting:1;
261 u8 bridged_dnat:1;
262 __u16 frag_max_size;
263 struct net_device *physindev;
264
265 /* always valid & non-NULL from FORWARD on, for physdev match */
266 struct net_device *physoutdev;
267 union {
268 /* prerouting: detect dnat in orig/reply direction */
269 __be32 ipv4_daddr;
270 struct in6_addr ipv6_daddr;
271
272 /* after prerouting + nat detected: store original source
273 * mac since neigh resolution overwrites it, only used while
274 * skb is out in neigh layer.
275 */
276 char neigh_header[8];
277 };
278};
279#endif
280
281struct sk_buff_head {
282 /* These two members must be first. */
283 struct sk_buff *next;
284 struct sk_buff *prev;
285
286 __u32 qlen;
287 spinlock_t lock;
288};
289
290struct sk_buff;
291
292/* To allow 64K frame to be packed as single skb without frag_list we
293 * require 64K/PAGE_SIZE pages plus 1 additional page to allow for
294 * buffers which do not start on a page boundary.
295 *
296 * Since GRO uses frags we allocate at least 16 regardless of page
297 * size.
298 */
299#if (65536/PAGE_SIZE + 1) < 16
300#define MAX_SKB_FRAGS 16UL
301#else
302#define MAX_SKB_FRAGS (65536/PAGE_SIZE + 1)
303#endif
304extern int sysctl_max_skb_frags;
305
306/* Set skb_shinfo(skb)->gso_size to this in case you want skb_segment to
307 * segment using its current segmentation instead.
308 */
309#define GSO_BY_FRAGS 0xFFFF
310
311typedef struct skb_frag_struct skb_frag_t;
312
313struct skb_frag_struct {
314 struct {
315 struct page *p;
316 } page;
317#if (BITS_PER_LONG > 32) || (PAGE_SIZE >= 65536)
318 __u32 page_offset;
319 __u32 size;
320#else
321 __u16 page_offset;
322 __u16 size;
323#endif
324};
325
326static inline unsigned int skb_frag_size(const skb_frag_t *frag)
327{
328 return frag->size;
329}
330
331static inline void skb_frag_size_set(skb_frag_t *frag, unsigned int size)
332{
333 frag->size = size;
334}
335
336static inline void skb_frag_size_add(skb_frag_t *frag, int delta)
337{
338 frag->size += delta;
339}
340
341static inline void skb_frag_size_sub(skb_frag_t *frag, int delta)
342{
343 frag->size -= delta;
344}
345
346#define HAVE_HW_TIME_STAMP
347
348/**
349 * struct skb_shared_hwtstamps - hardware time stamps
350 * @hwtstamp: hardware time stamp transformed into duration
351 * since arbitrary point in time
352 *
353 * Software time stamps generated by ktime_get_real() are stored in
354 * skb->tstamp.
355 *
356 * hwtstamps can only be compared against other hwtstamps from
357 * the same device.
358 *
359 * This structure is attached to packets as part of the
360 * &skb_shared_info. Use skb_hwtstamps() to get a pointer.
361 */
362struct skb_shared_hwtstamps {
363 ktime_t hwtstamp;
364};
365
366/* Definitions for tx_flags in struct skb_shared_info */
367enum {
368 /* generate hardware time stamp */
369 SKBTX_HW_TSTAMP = 1 << 0,
370
371 /* generate software time stamp when queueing packet to NIC */
372 SKBTX_SW_TSTAMP = 1 << 1,
373
374 /* device driver is going to provide hardware time stamp */
375 SKBTX_IN_PROGRESS = 1 << 2,
376
377 /* device driver supports TX zero-copy buffers */
378 SKBTX_DEV_ZEROCOPY = 1 << 3,
379
380 /* generate wifi status information (where possible) */
381 SKBTX_WIFI_STATUS = 1 << 4,
382
383 /* This indicates at least one fragment might be overwritten
384 * (as in vmsplice(), sendfile() ...)
385 * If we need to compute a TX checksum, we'll need to copy
386 * all frags to avoid possible bad checksum
387 */
388 SKBTX_SHARED_FRAG = 1 << 5,
389
390 /* generate software time stamp when entering packet scheduling */
391 SKBTX_SCHED_TSTAMP = 1 << 6,
392};
393
394#define SKBTX_ANY_SW_TSTAMP (SKBTX_SW_TSTAMP | \
395 SKBTX_SCHED_TSTAMP)
396#define SKBTX_ANY_TSTAMP (SKBTX_HW_TSTAMP | SKBTX_ANY_SW_TSTAMP)
397
398/*
399 * The callback notifies userspace to release buffers when skb DMA is done in
400 * lower device, the skb last reference should be 0 when calling this.
401 * The zerocopy_success argument is true if zero copy transmit occurred,
402 * false on data copy or out of memory error caused by data copy attempt.
403 * The ctx field is used to track device context.
404 * The desc field is used to track userspace buffer index.
405 */
406struct ubuf_info {
407 void (*callback)(struct ubuf_info *, bool zerocopy_success);
408 void *ctx;
409 unsigned long desc;
410};
411
412/* This data is invariant across clones and lives at
413 * the end of the header data, ie. at skb->end.
414 */
415struct skb_shared_info {
416 unsigned char nr_frags;
417 __u8 tx_flags;
418 unsigned short gso_size;
419 /* Warning: this field is not always filled in (UFO)! */
420 unsigned short gso_segs;
421 unsigned short gso_type;
422 struct sk_buff *frag_list;
423 struct skb_shared_hwtstamps hwtstamps;
424 u32 tskey;
425 __be32 ip6_frag_id;
426
427 /*
428 * Warning : all fields before dataref are cleared in __alloc_skb()
429 */
430 atomic_t dataref;
431
432 /* Intermediate layers must ensure that destructor_arg
433 * remains valid until skb destructor */
434 void * destructor_arg;
435
436 /* must be last field, see pskb_expand_head() */
437 skb_frag_t frags[MAX_SKB_FRAGS];
438};
439
440/* We divide dataref into two halves. The higher 16 bits hold references
441 * to the payload part of skb->data. The lower 16 bits hold references to
442 * the entire skb->data. A clone of a headerless skb holds the length of
443 * the header in skb->hdr_len.
444 *
445 * All users must obey the rule that the skb->data reference count must be
446 * greater than or equal to the payload reference count.
447 *
448 * Holding a reference to the payload part means that the user does not
449 * care about modifications to the header part of skb->data.
450 */
451#define SKB_DATAREF_SHIFT 16
452#define SKB_DATAREF_MASK ((1 << SKB_DATAREF_SHIFT) - 1)
453
454
455enum {
456 SKB_FCLONE_UNAVAILABLE, /* skb has no fclone (from head_cache) */
457 SKB_FCLONE_ORIG, /* orig skb (from fclone_cache) */
458 SKB_FCLONE_CLONE, /* companion fclone skb (from fclone_cache) */
459};
460
461enum {
462 SKB_GSO_TCPV4 = 1 << 0,
463 SKB_GSO_UDP = 1 << 1,
464
465 /* This indicates the skb is from an untrusted source. */
466 SKB_GSO_DODGY = 1 << 2,
467
468 /* This indicates the tcp segment has CWR set. */
469 SKB_GSO_TCP_ECN = 1 << 3,
470
471 SKB_GSO_TCP_FIXEDID = 1 << 4,
472
473 SKB_GSO_TCPV6 = 1 << 5,
474
475 SKB_GSO_FCOE = 1 << 6,
476
477 SKB_GSO_GRE = 1 << 7,
478
479 SKB_GSO_GRE_CSUM = 1 << 8,
480
481 SKB_GSO_IPXIP4 = 1 << 9,
482
483 SKB_GSO_IPXIP6 = 1 << 10,
484
485 SKB_GSO_UDP_TUNNEL = 1 << 11,
486
487 SKB_GSO_UDP_TUNNEL_CSUM = 1 << 12,
488
489 SKB_GSO_PARTIAL = 1 << 13,
490
491 SKB_GSO_TUNNEL_REMCSUM = 1 << 14,
492
493 SKB_GSO_SCTP = 1 << 15,
494};
495
496#if BITS_PER_LONG > 32
497#define NET_SKBUFF_DATA_USES_OFFSET 1
498#endif
499
500#ifdef NET_SKBUFF_DATA_USES_OFFSET
501typedef unsigned int sk_buff_data_t;
502#else
503typedef unsigned char *sk_buff_data_t;
504#endif
505
506/**
507 * struct skb_mstamp - multi resolution time stamps
508 * @stamp_us: timestamp in us resolution
509 * @stamp_jiffies: timestamp in jiffies
510 */
511struct skb_mstamp {
512 union {
513 u64 v64;
514 struct {
515 u32 stamp_us;
516 u32 stamp_jiffies;
517 };
518 };
519};
520
521/**
522 * skb_mstamp_get - get current timestamp
523 * @cl: place to store timestamps
524 */
525static inline void skb_mstamp_get(struct skb_mstamp *cl)
526{
527 u64 val = local_clock();
528
529 do_div(val, NSEC_PER_USEC);
530 cl->stamp_us = (u32)val;
531 cl->stamp_jiffies = (u32)jiffies;
532}
533
534/**
535 * skb_mstamp_delta - compute the difference in usec between two skb_mstamp
536 * @t1: pointer to newest sample
537 * @t0: pointer to oldest sample
538 */
539static inline u32 skb_mstamp_us_delta(const struct skb_mstamp *t1,
540 const struct skb_mstamp *t0)
541{
542 s32 delta_us = t1->stamp_us - t0->stamp_us;
543 u32 delta_jiffies = t1->stamp_jiffies - t0->stamp_jiffies;
544
545 /* If delta_us is negative, this might be because interval is too big,
546 * or local_clock() drift is too big : fallback using jiffies.
547 */
548 if (delta_us <= 0 ||
549 delta_jiffies >= (INT_MAX / (USEC_PER_SEC / HZ)))
550
551 delta_us = jiffies_to_usecs(delta_jiffies);
552
553 return delta_us;
554}
555
556static inline bool skb_mstamp_after(const struct skb_mstamp *t1,
557 const struct skb_mstamp *t0)
558{
559 s32 diff = t1->stamp_jiffies - t0->stamp_jiffies;
560
561 if (!diff)
562 diff = t1->stamp_us - t0->stamp_us;
563 return diff > 0;
564}
565
566/**
567 * struct sk_buff - socket buffer
568 * @next: Next buffer in list
569 * @prev: Previous buffer in list
570 * @tstamp: Time we arrived/left
571 * @rbnode: RB tree node, alternative to next/prev for netem/tcp
572 * @sk: Socket we are owned by
573 * @dev: Device we arrived on/are leaving by
574 * @cb: Control buffer. Free for use by every layer. Put private vars here
575 * @_skb_refdst: destination entry (with norefcount bit)
576 * @sp: the security path, used for xfrm
577 * @len: Length of actual data
578 * @data_len: Data length
579 * @mac_len: Length of link layer header
580 * @hdr_len: writable header length of cloned skb
581 * @csum: Checksum (must include start/offset pair)
582 * @csum_start: Offset from skb->head where checksumming should start
583 * @csum_offset: Offset from csum_start where checksum should be stored
584 * @priority: Packet queueing priority
585 * @ignore_df: allow local fragmentation
586 * @cloned: Head may be cloned (check refcnt to be sure)
587 * @ip_summed: Driver fed us an IP checksum
588 * @nohdr: Payload reference only, must not modify header
589 * @pkt_type: Packet class
590 * @fclone: skbuff clone status
591 * @ipvs_property: skbuff is owned by ipvs
592 * @tc_skip_classify: do not classify packet. set by IFB device
593 * @tc_at_ingress: used within tc_classify to distinguish in/egress
594 * @tc_redirected: packet was redirected by a tc action
595 * @tc_from_ingress: if tc_redirected, tc_at_ingress at time of redirect
596 * @peeked: this packet has been seen already, so stats have been
597 * done for it, don't do them again
598 * @nf_trace: netfilter packet trace flag
599 * @protocol: Packet protocol from driver
600 * @destructor: Destruct function
601 * @_nfct: Associated connection, if any (with nfctinfo bits)
602 * @nf_bridge: Saved data about a bridged frame - see br_netfilter.c
603 * @skb_iif: ifindex of device we arrived on
604 * @tc_index: Traffic control index
605 * @hash: the packet hash
606 * @queue_mapping: Queue mapping for multiqueue devices
607 * @xmit_more: More SKBs are pending for this queue
608 * @ndisc_nodetype: router type (from link layer)
609 * @ooo_okay: allow the mapping of a socket to a queue to be changed
610 * @l4_hash: indicate hash is a canonical 4-tuple hash over transport
611 * ports.
612 * @sw_hash: indicates hash was computed in software stack
613 * @wifi_acked_valid: wifi_acked was set
614 * @wifi_acked: whether frame was acked on wifi or not
615 * @no_fcs: Request NIC to treat last 4 bytes as Ethernet FCS
616 * @dst_pending_confirm: need to confirm neighbour
617 * @napi_id: id of the NAPI struct this skb came from
618 * @secmark: security marking
619 * @mark: Generic packet mark
620 * @vlan_proto: vlan encapsulation protocol
621 * @vlan_tci: vlan tag control information
622 * @inner_protocol: Protocol (encapsulation)
623 * @inner_transport_header: Inner transport layer header (encapsulation)
624 * @inner_network_header: Network layer header (encapsulation)
625 * @inner_mac_header: Link layer header (encapsulation)
626 * @transport_header: Transport layer header
627 * @network_header: Network layer header
628 * @mac_header: Link layer header
629 * @tail: Tail pointer
630 * @end: End pointer
631 * @head: Head of buffer
632 * @data: Data head pointer
633 * @truesize: Buffer size
634 * @users: User count - see {datagram,tcp}.c
635 */
636
637struct sk_buff {
638 union {
639 struct {
640 /* These two members must be first. */
641 struct sk_buff *next;
642 struct sk_buff *prev;
643
644 union {
645 ktime_t tstamp;
646 struct skb_mstamp skb_mstamp;
647 };
648 };
649 struct rb_node rbnode; /* used in netem & tcp stack */
650 };
651 struct sock *sk;
652
653 union {
654 struct net_device *dev;
655 /* Some protocols might use this space to store information,
656 * while device pointer would be NULL.
657 * UDP receive path is one user.
658 */
659 unsigned long dev_scratch;
660 };
661 /*
662 * This is the control buffer. It is free to use for every
663 * layer. Please put your private variables there. If you
664 * want to keep them across layers you have to do a skb_clone()
665 * first. This is owned by whoever has the skb queued ATM.
666 */
667 char cb[48] __aligned(8);
668
669 unsigned long _skb_refdst;
670 void (*destructor)(struct sk_buff *skb);
671#ifdef CONFIG_XFRM
672 struct sec_path *sp;
673#endif
674#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
675 unsigned long _nfct;
676#endif
677#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
678 struct nf_bridge_info *nf_bridge;
679#endif
680 unsigned int len,
681 data_len;
682 __u16 mac_len,
683 hdr_len;
684
685 /* Following fields are _not_ copied in __copy_skb_header()
686 * Note that queue_mapping is here mostly to fill a hole.
687 */
688 kmemcheck_bitfield_begin(flags1);
689 __u16 queue_mapping;
690
691/* if you move cloned around you also must adapt those constants */
692#ifdef __BIG_ENDIAN_BITFIELD
693#define CLONED_MASK (1 << 7)
694#else
695#define CLONED_MASK 1
696#endif
697#define CLONED_OFFSET() offsetof(struct sk_buff, __cloned_offset)
698
699 __u8 __cloned_offset[0];
700 __u8 cloned:1,
701 nohdr:1,
702 fclone:2,
703 peeked:1,
704 head_frag:1,
705 xmit_more:1,
706 __unused:1; /* one bit hole */
707 kmemcheck_bitfield_end(flags1);
708
709 /* fields enclosed in headers_start/headers_end are copied
710 * using a single memcpy() in __copy_skb_header()
711 */
712 /* private: */
713 __u32 headers_start[0];
714 /* public: */
715
716/* if you move pkt_type around you also must adapt those constants */
717#ifdef __BIG_ENDIAN_BITFIELD
718#define PKT_TYPE_MAX (7 << 5)
719#else
720#define PKT_TYPE_MAX 7
721#endif
722#define PKT_TYPE_OFFSET() offsetof(struct sk_buff, __pkt_type_offset)
723
724 __u8 __pkt_type_offset[0];
725 __u8 pkt_type:3;
726 __u8 pfmemalloc:1;
727 __u8 ignore_df:1;
728
729 __u8 nf_trace:1;
730 __u8 ip_summed:2;
731 __u8 ooo_okay:1;
732 __u8 l4_hash:1;
733 __u8 sw_hash:1;
734 __u8 wifi_acked_valid:1;
735 __u8 wifi_acked:1;
736
737 __u8 no_fcs:1;
738 /* Indicates the inner headers are valid in the skbuff. */
739 __u8 encapsulation:1;
740 __u8 encap_hdr_csum:1;
741 __u8 csum_valid:1;
742 __u8 csum_complete_sw:1;
743 __u8 csum_level:2;
744 __u8 csum_bad:1;
745
746 __u8 dst_pending_confirm:1;
747#ifdef CONFIG_IPV6_NDISC_NODETYPE
748 __u8 ndisc_nodetype:2;
749#endif
750 __u8 ipvs_property:1;
751 __u8 inner_protocol_type:1;
752 __u8 remcsum_offload:1;
753#ifdef CONFIG_NET_SWITCHDEV
754 __u8 offload_fwd_mark:1;
755#endif
756#ifdef CONFIG_NET_CLS_ACT
757 __u8 tc_skip_classify:1;
758 __u8 tc_at_ingress:1;
759 __u8 tc_redirected:1;
760 __u8 tc_from_ingress:1;
761#endif
762
763#ifdef CONFIG_NET_SCHED
764 __u16 tc_index; /* traffic control index */
765#endif
766
767 union {
768 __wsum csum;
769 struct {
770 __u16 csum_start;
771 __u16 csum_offset;
772 };
773 };
774 __u32 priority;
775 int skb_iif;
776 __u32 hash;
777 __be16 vlan_proto;
778 __u16 vlan_tci;
779#if defined(CONFIG_NET_RX_BUSY_POLL) || defined(CONFIG_XPS)
780 union {
781 unsigned int napi_id;
782 unsigned int sender_cpu;
783 };
784#endif
785#ifdef CONFIG_NETWORK_SECMARK
786 __u32 secmark;
787#endif
788
789 union {
790 __u32 mark;
791 __u32 reserved_tailroom;
792 };
793
794 union {
795 __be16 inner_protocol;
796 __u8 inner_ipproto;
797 };
798
799 __u16 inner_transport_header;
800 __u16 inner_network_header;
801 __u16 inner_mac_header;
802
803 __be16 protocol;
804 __u16 transport_header;
805 __u16 network_header;
806 __u16 mac_header;
807
808 /* private: */
809 __u32 headers_end[0];
810 /* public: */
811
812 /* These elements must be at the end, see alloc_skb() for details. */
813 sk_buff_data_t tail;
814 sk_buff_data_t end;
815 unsigned char *head,
816 *data;
817 unsigned int truesize;
818 atomic_t users;
819};
820
821#ifdef __KERNEL__
822/*
823 * Handling routines are only of interest to the kernel
824 */
825#include <linux/slab.h>
826
827
828#define SKB_ALLOC_FCLONE 0x01
829#define SKB_ALLOC_RX 0x02
830#define SKB_ALLOC_NAPI 0x04
831
832/* Returns true if the skb was allocated from PFMEMALLOC reserves */
833static inline bool skb_pfmemalloc(const struct sk_buff *skb)
834{
835 return unlikely(skb->pfmemalloc);
836}
837
838/*
839 * skb might have a dst pointer attached, refcounted or not.
840 * _skb_refdst low order bit is set if refcount was _not_ taken
841 */
842#define SKB_DST_NOREF 1UL
843#define SKB_DST_PTRMASK ~(SKB_DST_NOREF)
844
845#define SKB_NFCT_PTRMASK ~(7UL)
846/**
847 * skb_dst - returns skb dst_entry
848 * @skb: buffer
849 *
850 * Returns skb dst_entry, regardless of reference taken or not.
851 */
852static inline struct dst_entry *skb_dst(const struct sk_buff *skb)
853{
854 /* If refdst was not refcounted, check we still are in a
855 * rcu_read_lock section
856 */
857 WARN_ON((skb->_skb_refdst & SKB_DST_NOREF) &&
858 !rcu_read_lock_held() &&
859 !rcu_read_lock_bh_held());
860 return (struct dst_entry *)(skb->_skb_refdst & SKB_DST_PTRMASK);
861}
862
863/**
864 * skb_dst_set - sets skb dst
865 * @skb: buffer
866 * @dst: dst entry
867 *
868 * Sets skb dst, assuming a reference was taken on dst and should
869 * be released by skb_dst_drop()
870 */
871static inline void skb_dst_set(struct sk_buff *skb, struct dst_entry *dst)
872{
873 skb->_skb_refdst = (unsigned long)dst;
874}
875
876/**
877 * skb_dst_set_noref - sets skb dst, hopefully, without taking reference
878 * @skb: buffer
879 * @dst: dst entry
880 *
881 * Sets skb dst, assuming a reference was not taken on dst.
882 * If dst entry is cached, we do not take reference and dst_release
883 * will be avoided by refdst_drop. If dst entry is not cached, we take
884 * reference, so that last dst_release can destroy the dst immediately.
885 */
886static inline void skb_dst_set_noref(struct sk_buff *skb, struct dst_entry *dst)
887{
888 WARN_ON(!rcu_read_lock_held() && !rcu_read_lock_bh_held());
889 skb->_skb_refdst = (unsigned long)dst | SKB_DST_NOREF;
890}
891
892/**
893 * skb_dst_is_noref - Test if skb dst isn't refcounted
894 * @skb: buffer
895 */
896static inline bool skb_dst_is_noref(const struct sk_buff *skb)
897{
898 return (skb->_skb_refdst & SKB_DST_NOREF) && skb_dst(skb);
899}
900
901static inline struct rtable *skb_rtable(const struct sk_buff *skb)
902{
903 return (struct rtable *)skb_dst(skb);
904}
905
906/* For mangling skb->pkt_type from user space side from applications
907 * such as nft, tc, etc, we only allow a conservative subset of
908 * possible pkt_types to be set.
909*/
910static inline bool skb_pkt_type_ok(u32 ptype)
911{
912 return ptype <= PACKET_OTHERHOST;
913}
914
915void kfree_skb(struct sk_buff *skb);
916void kfree_skb_list(struct sk_buff *segs);
917void skb_tx_error(struct sk_buff *skb);
918void consume_skb(struct sk_buff *skb);
919void __kfree_skb(struct sk_buff *skb);
920extern struct kmem_cache *skbuff_head_cache;
921
922void kfree_skb_partial(struct sk_buff *skb, bool head_stolen);
923bool skb_try_coalesce(struct sk_buff *to, struct sk_buff *from,
924 bool *fragstolen, int *delta_truesize);
925
926struct sk_buff *__alloc_skb(unsigned int size, gfp_t priority, int flags,
927 int node);
928struct sk_buff *__build_skb(void *data, unsigned int frag_size);
929struct sk_buff *build_skb(void *data, unsigned int frag_size);
930static inline struct sk_buff *alloc_skb(unsigned int size,
931 gfp_t priority)
932{
933 return __alloc_skb(size, priority, 0, NUMA_NO_NODE);
934}
935
936struct sk_buff *alloc_skb_with_frags(unsigned long header_len,
937 unsigned long data_len,
938 int max_page_order,
939 int *errcode,
940 gfp_t gfp_mask);
941
942/* Layout of fast clones : [skb1][skb2][fclone_ref] */
943struct sk_buff_fclones {
944 struct sk_buff skb1;
945
946 struct sk_buff skb2;
947
948 atomic_t fclone_ref;
949};
950
951/**
952 * skb_fclone_busy - check if fclone is busy
953 * @sk: socket
954 * @skb: buffer
955 *
956 * Returns true if skb is a fast clone, and its clone is not freed.
957 * Some drivers call skb_orphan() in their ndo_start_xmit(),
958 * so we also check that this didnt happen.
959 */
960static inline bool skb_fclone_busy(const struct sock *sk,
961 const struct sk_buff *skb)
962{
963 const struct sk_buff_fclones *fclones;
964
965 fclones = container_of(skb, struct sk_buff_fclones, skb1);
966
967 return skb->fclone == SKB_FCLONE_ORIG &&
968 atomic_read(&fclones->fclone_ref) > 1 &&
969 fclones->skb2.sk == sk;
970}
971
972static inline struct sk_buff *alloc_skb_fclone(unsigned int size,
973 gfp_t priority)
974{
975 return __alloc_skb(size, priority, SKB_ALLOC_FCLONE, NUMA_NO_NODE);
976}
977
978struct sk_buff *__alloc_skb_head(gfp_t priority, int node);
979static inline struct sk_buff *alloc_skb_head(gfp_t priority)
980{
981 return __alloc_skb_head(priority, -1);
982}
983
984struct sk_buff *skb_morph(struct sk_buff *dst, struct sk_buff *src);
985int skb_copy_ubufs(struct sk_buff *skb, gfp_t gfp_mask);
986struct sk_buff *skb_clone(struct sk_buff *skb, gfp_t priority);
987struct sk_buff *skb_copy(const struct sk_buff *skb, gfp_t priority);
988struct sk_buff *__pskb_copy_fclone(struct sk_buff *skb, int headroom,
989 gfp_t gfp_mask, bool fclone);
990static inline struct sk_buff *__pskb_copy(struct sk_buff *skb, int headroom,
991 gfp_t gfp_mask)
992{
993 return __pskb_copy_fclone(skb, headroom, gfp_mask, false);
994}
995
996int pskb_expand_head(struct sk_buff *skb, int nhead, int ntail, gfp_t gfp_mask);
997struct sk_buff *skb_realloc_headroom(struct sk_buff *skb,
998 unsigned int headroom);
999struct sk_buff *skb_copy_expand(const struct sk_buff *skb, int newheadroom,
1000 int newtailroom, gfp_t priority);
1001int skb_to_sgvec_nomark(struct sk_buff *skb, struct scatterlist *sg,
1002 int offset, int len);
1003int skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset,
1004 int len);
1005int skb_cow_data(struct sk_buff *skb, int tailbits, struct sk_buff **trailer);
1006int skb_pad(struct sk_buff *skb, int pad);
1007#define dev_kfree_skb(a) consume_skb(a)
1008
1009int skb_append_datato_frags(struct sock *sk, struct sk_buff *skb,
1010 int getfrag(void *from, char *to, int offset,
1011 int len, int odd, struct sk_buff *skb),
1012 void *from, int length);
1013
1014int skb_append_pagefrags(struct sk_buff *skb, struct page *page,
1015 int offset, size_t size);
1016
1017struct skb_seq_state {
1018 __u32 lower_offset;
1019 __u32 upper_offset;
1020 __u32 frag_idx;
1021 __u32 stepped_offset;
1022 struct sk_buff *root_skb;
1023 struct sk_buff *cur_skb;
1024 __u8 *frag_data;
1025};
1026
1027void skb_prepare_seq_read(struct sk_buff *skb, unsigned int from,
1028 unsigned int to, struct skb_seq_state *st);
1029unsigned int skb_seq_read(unsigned int consumed, const u8 **data,
1030 struct skb_seq_state *st);
1031void skb_abort_seq_read(struct skb_seq_state *st);
1032
1033unsigned int skb_find_text(struct sk_buff *skb, unsigned int from,
1034 unsigned int to, struct ts_config *config);
1035
1036/*
1037 * Packet hash types specify the type of hash in skb_set_hash.
1038 *
1039 * Hash types refer to the protocol layer addresses which are used to
1040 * construct a packet's hash. The hashes are used to differentiate or identify
1041 * flows of the protocol layer for the hash type. Hash types are either
1042 * layer-2 (L2), layer-3 (L3), or layer-4 (L4).
1043 *
1044 * Properties of hashes:
1045 *
1046 * 1) Two packets in different flows have different hash values
1047 * 2) Two packets in the same flow should have the same hash value
1048 *
1049 * A hash at a higher layer is considered to be more specific. A driver should
1050 * set the most specific hash possible.
1051 *
1052 * A driver cannot indicate a more specific hash than the layer at which a hash
1053 * was computed. For instance an L3 hash cannot be set as an L4 hash.
1054 *
1055 * A driver may indicate a hash level which is less specific than the
1056 * actual layer the hash was computed on. For instance, a hash computed
1057 * at L4 may be considered an L3 hash. This should only be done if the
1058 * driver can't unambiguously determine that the HW computed the hash at
1059 * the higher layer. Note that the "should" in the second property above
1060 * permits this.
1061 */
1062enum pkt_hash_types {
1063 PKT_HASH_TYPE_NONE, /* Undefined type */
1064 PKT_HASH_TYPE_L2, /* Input: src_MAC, dest_MAC */
1065 PKT_HASH_TYPE_L3, /* Input: src_IP, dst_IP */
1066 PKT_HASH_TYPE_L4, /* Input: src_IP, dst_IP, src_port, dst_port */
1067};
1068
1069static inline void skb_clear_hash(struct sk_buff *skb)
1070{
1071 skb->hash = 0;
1072 skb->sw_hash = 0;
1073 skb->l4_hash = 0;
1074}
1075
1076static inline void skb_clear_hash_if_not_l4(struct sk_buff *skb)
1077{
1078 if (!skb->l4_hash)
1079 skb_clear_hash(skb);
1080}
1081
1082static inline void
1083__skb_set_hash(struct sk_buff *skb, __u32 hash, bool is_sw, bool is_l4)
1084{
1085 skb->l4_hash = is_l4;
1086 skb->sw_hash = is_sw;
1087 skb->hash = hash;
1088}
1089
1090static inline void
1091skb_set_hash(struct sk_buff *skb, __u32 hash, enum pkt_hash_types type)
1092{
1093 /* Used by drivers to set hash from HW */
1094 __skb_set_hash(skb, hash, false, type == PKT_HASH_TYPE_L4);
1095}
1096
1097static inline void
1098__skb_set_sw_hash(struct sk_buff *skb, __u32 hash, bool is_l4)
1099{
1100 __skb_set_hash(skb, hash, true, is_l4);
1101}
1102
1103void __skb_get_hash(struct sk_buff *skb);
1104u32 __skb_get_hash_symmetric(const struct sk_buff *skb);
1105u32 skb_get_poff(const struct sk_buff *skb);
1106u32 __skb_get_poff(const struct sk_buff *skb, void *data,
1107 const struct flow_keys *keys, int hlen);
1108__be32 __skb_flow_get_ports(const struct sk_buff *skb, int thoff, u8 ip_proto,
1109 void *data, int hlen_proto);
1110
1111static inline __be32 skb_flow_get_ports(const struct sk_buff *skb,
1112 int thoff, u8 ip_proto)
1113{
1114 return __skb_flow_get_ports(skb, thoff, ip_proto, NULL, 0);
1115}
1116
1117void skb_flow_dissector_init(struct flow_dissector *flow_dissector,
1118 const struct flow_dissector_key *key,
1119 unsigned int key_count);
1120
1121bool __skb_flow_dissect(const struct sk_buff *skb,
1122 struct flow_dissector *flow_dissector,
1123 void *target_container,
1124 void *data, __be16 proto, int nhoff, int hlen,
1125 unsigned int flags);
1126
1127static inline bool skb_flow_dissect(const struct sk_buff *skb,
1128 struct flow_dissector *flow_dissector,
1129 void *target_container, unsigned int flags)
1130{
1131 return __skb_flow_dissect(skb, flow_dissector, target_container,
1132 NULL, 0, 0, 0, flags);
1133}
1134
1135static inline bool skb_flow_dissect_flow_keys(const struct sk_buff *skb,
1136 struct flow_keys *flow,
1137 unsigned int flags)
1138{
1139 memset(flow, 0, sizeof(*flow));
1140 return __skb_flow_dissect(skb, &flow_keys_dissector, flow,
1141 NULL, 0, 0, 0, flags);
1142}
1143
1144static inline bool skb_flow_dissect_flow_keys_buf(struct flow_keys *flow,
1145 void *data, __be16 proto,
1146 int nhoff, int hlen,
1147 unsigned int flags)
1148{
1149 memset(flow, 0, sizeof(*flow));
1150 return __skb_flow_dissect(NULL, &flow_keys_buf_dissector, flow,
1151 data, proto, nhoff, hlen, flags);
1152}
1153
1154static inline __u32 skb_get_hash(struct sk_buff *skb)
1155{
1156 if (!skb->l4_hash && !skb->sw_hash)
1157 __skb_get_hash(skb);
1158
1159 return skb->hash;
1160}
1161
1162__u32 __skb_get_hash_flowi6(struct sk_buff *skb, const struct flowi6 *fl6);
1163
1164static inline __u32 skb_get_hash_flowi6(struct sk_buff *skb, const struct flowi6 *fl6)
1165{
1166 if (!skb->l4_hash && !skb->sw_hash) {
1167 struct flow_keys keys;
1168 __u32 hash = __get_hash_from_flowi6(fl6, &keys);
1169
1170 __skb_set_sw_hash(skb, hash, flow_keys_have_l4(&keys));
1171 }
1172
1173 return skb->hash;
1174}
1175
1176__u32 __skb_get_hash_flowi4(struct sk_buff *skb, const struct flowi4 *fl);
1177
1178static inline __u32 skb_get_hash_flowi4(struct sk_buff *skb, const struct flowi4 *fl4)
1179{
1180 if (!skb->l4_hash && !skb->sw_hash) {
1181 struct flow_keys keys;
1182 __u32 hash = __get_hash_from_flowi4(fl4, &keys);
1183
1184 __skb_set_sw_hash(skb, hash, flow_keys_have_l4(&keys));
1185 }
1186
1187 return skb->hash;
1188}
1189
1190__u32 skb_get_hash_perturb(const struct sk_buff *skb, u32 perturb);
1191
1192static inline __u32 skb_get_hash_raw(const struct sk_buff *skb)
1193{
1194 return skb->hash;
1195}
1196
1197static inline void skb_copy_hash(struct sk_buff *to, const struct sk_buff *from)
1198{
1199 to->hash = from->hash;
1200 to->sw_hash = from->sw_hash;
1201 to->l4_hash = from->l4_hash;
1202};
1203
1204#ifdef NET_SKBUFF_DATA_USES_OFFSET
1205static inline unsigned char *skb_end_pointer(const struct sk_buff *skb)
1206{
1207 return skb->head + skb->end;
1208}
1209
1210static inline unsigned int skb_end_offset(const struct sk_buff *skb)
1211{
1212 return skb->end;
1213}
1214#else
1215static inline unsigned char *skb_end_pointer(const struct sk_buff *skb)
1216{
1217 return skb->end;
1218}
1219
1220static inline unsigned int skb_end_offset(const struct sk_buff *skb)
1221{
1222 return skb->end - skb->head;
1223}
1224#endif
1225
1226/* Internal */
1227#define skb_shinfo(SKB) ((struct skb_shared_info *)(skb_end_pointer(SKB)))
1228
1229static inline struct skb_shared_hwtstamps *skb_hwtstamps(struct sk_buff *skb)
1230{
1231 return &skb_shinfo(skb)->hwtstamps;
1232}
1233
1234/**
1235 * skb_queue_empty - check if a queue is empty
1236 * @list: queue head
1237 *
1238 * Returns true if the queue is empty, false otherwise.
1239 */
1240static inline int skb_queue_empty(const struct sk_buff_head *list)
1241{
1242 return list->next == (const struct sk_buff *) list;
1243}
1244
1245/**
1246 * skb_queue_is_last - check if skb is the last entry in the queue
1247 * @list: queue head
1248 * @skb: buffer
1249 *
1250 * Returns true if @skb is the last buffer on the list.
1251 */
1252static inline bool skb_queue_is_last(const struct sk_buff_head *list,
1253 const struct sk_buff *skb)
1254{
1255 return skb->next == (const struct sk_buff *) list;
1256}
1257
1258/**
1259 * skb_queue_is_first - check if skb is the first entry in the queue
1260 * @list: queue head
1261 * @skb: buffer
1262 *
1263 * Returns true if @skb is the first buffer on the list.
1264 */
1265static inline bool skb_queue_is_first(const struct sk_buff_head *list,
1266 const struct sk_buff *skb)
1267{
1268 return skb->prev == (const struct sk_buff *) list;
1269}
1270
1271/**
1272 * skb_queue_next - return the next packet in the queue
1273 * @list: queue head
1274 * @skb: current buffer
1275 *
1276 * Return the next packet in @list after @skb. It is only valid to
1277 * call this if skb_queue_is_last() evaluates to false.
1278 */
1279static inline struct sk_buff *skb_queue_next(const struct sk_buff_head *list,
1280 const struct sk_buff *skb)
1281{
1282 /* This BUG_ON may seem severe, but if we just return then we
1283 * are going to dereference garbage.
1284 */
1285 BUG_ON(skb_queue_is_last(list, skb));
1286 return skb->next;
1287}
1288
1289/**
1290 * skb_queue_prev - return the prev packet in the queue
1291 * @list: queue head
1292 * @skb: current buffer
1293 *
1294 * Return the prev packet in @list before @skb. It is only valid to
1295 * call this if skb_queue_is_first() evaluates to false.
1296 */
1297static inline struct sk_buff *skb_queue_prev(const struct sk_buff_head *list,
1298 const struct sk_buff *skb)
1299{
1300 /* This BUG_ON may seem severe, but if we just return then we
1301 * are going to dereference garbage.
1302 */
1303 BUG_ON(skb_queue_is_first(list, skb));
1304 return skb->prev;
1305}
1306
1307/**
1308 * skb_get - reference buffer
1309 * @skb: buffer to reference
1310 *
1311 * Makes another reference to a socket buffer and returns a pointer
1312 * to the buffer.
1313 */
1314static inline struct sk_buff *skb_get(struct sk_buff *skb)
1315{
1316 atomic_inc(&skb->users);
1317 return skb;
1318}
1319
1320/*
1321 * If users == 1, we are the only owner and are can avoid redundant
1322 * atomic change.
1323 */
1324
1325/**
1326 * skb_cloned - is the buffer a clone
1327 * @skb: buffer to check
1328 *
1329 * Returns true if the buffer was generated with skb_clone() and is
1330 * one of multiple shared copies of the buffer. Cloned buffers are
1331 * shared data so must not be written to under normal circumstances.
1332 */
1333static inline int skb_cloned(const struct sk_buff *skb)
1334{
1335 return skb->cloned &&
1336 (atomic_read(&skb_shinfo(skb)->dataref) & SKB_DATAREF_MASK) != 1;
1337}
1338
1339static inline int skb_unclone(struct sk_buff *skb, gfp_t pri)
1340{
1341 might_sleep_if(gfpflags_allow_blocking(pri));
1342
1343 if (skb_cloned(skb))
1344 return pskb_expand_head(skb, 0, 0, pri);
1345
1346 return 0;
1347}
1348
1349/**
1350 * skb_header_cloned - is the header a clone
1351 * @skb: buffer to check
1352 *
1353 * Returns true if modifying the header part of the buffer requires
1354 * the data to be copied.
1355 */
1356static inline int skb_header_cloned(const struct sk_buff *skb)
1357{
1358 int dataref;
1359
1360 if (!skb->cloned)
1361 return 0;
1362
1363 dataref = atomic_read(&skb_shinfo(skb)->dataref);
1364 dataref = (dataref & SKB_DATAREF_MASK) - (dataref >> SKB_DATAREF_SHIFT);
1365 return dataref != 1;
1366}
1367
1368static inline int skb_header_unclone(struct sk_buff *skb, gfp_t pri)
1369{
1370 might_sleep_if(gfpflags_allow_blocking(pri));
1371
1372 if (skb_header_cloned(skb))
1373 return pskb_expand_head(skb, 0, 0, pri);
1374
1375 return 0;
1376}
1377
1378/**
1379 * skb_header_release - release reference to header
1380 * @skb: buffer to operate on
1381 *
1382 * Drop a reference to the header part of the buffer. This is done
1383 * by acquiring a payload reference. You must not read from the header
1384 * part of skb->data after this.
1385 * Note : Check if you can use __skb_header_release() instead.
1386 */
1387static inline void skb_header_release(struct sk_buff *skb)
1388{
1389 BUG_ON(skb->nohdr);
1390 skb->nohdr = 1;
1391 atomic_add(1 << SKB_DATAREF_SHIFT, &skb_shinfo(skb)->dataref);
1392}
1393
1394/**
1395 * __skb_header_release - release reference to header
1396 * @skb: buffer to operate on
1397 *
1398 * Variant of skb_header_release() assuming skb is private to caller.
1399 * We can avoid one atomic operation.
1400 */
1401static inline void __skb_header_release(struct sk_buff *skb)
1402{
1403 skb->nohdr = 1;
1404 atomic_set(&skb_shinfo(skb)->dataref, 1 + (1 << SKB_DATAREF_SHIFT));
1405}
1406
1407
1408/**
1409 * skb_shared - is the buffer shared
1410 * @skb: buffer to check
1411 *
1412 * Returns true if more than one person has a reference to this
1413 * buffer.
1414 */
1415static inline int skb_shared(const struct sk_buff *skb)
1416{
1417 return atomic_read(&skb->users) != 1;
1418}
1419
1420/**
1421 * skb_share_check - check if buffer is shared and if so clone it
1422 * @skb: buffer to check
1423 * @pri: priority for memory allocation
1424 *
1425 * If the buffer is shared the buffer is cloned and the old copy
1426 * drops a reference. A new clone with a single reference is returned.
1427 * If the buffer is not shared the original buffer is returned. When
1428 * being called from interrupt status or with spinlocks held pri must
1429 * be GFP_ATOMIC.
1430 *
1431 * NULL is returned on a memory allocation failure.
1432 */
1433static inline struct sk_buff *skb_share_check(struct sk_buff *skb, gfp_t pri)
1434{
1435 might_sleep_if(gfpflags_allow_blocking(pri));
1436 if (skb_shared(skb)) {
1437 struct sk_buff *nskb = skb_clone(skb, pri);
1438
1439 if (likely(nskb))
1440 consume_skb(skb);
1441 else
1442 kfree_skb(skb);
1443 skb = nskb;
1444 }
1445 return skb;
1446}
1447
1448/*
1449 * Copy shared buffers into a new sk_buff. We effectively do COW on
1450 * packets to handle cases where we have a local reader and forward
1451 * and a couple of other messy ones. The normal one is tcpdumping
1452 * a packet thats being forwarded.
1453 */
1454
1455/**
1456 * skb_unshare - make a copy of a shared buffer
1457 * @skb: buffer to check
1458 * @pri: priority for memory allocation
1459 *
1460 * If the socket buffer is a clone then this function creates a new
1461 * copy of the data, drops a reference count on the old copy and returns
1462 * the new copy with the reference count at 1. If the buffer is not a clone
1463 * the original buffer is returned. When called with a spinlock held or
1464 * from interrupt state @pri must be %GFP_ATOMIC
1465 *
1466 * %NULL is returned on a memory allocation failure.
1467 */
1468static inline struct sk_buff *skb_unshare(struct sk_buff *skb,
1469 gfp_t pri)
1470{
1471 might_sleep_if(gfpflags_allow_blocking(pri));
1472 if (skb_cloned(skb)) {
1473 struct sk_buff *nskb = skb_copy(skb, pri);
1474
1475 /* Free our shared copy */
1476 if (likely(nskb))
1477 consume_skb(skb);
1478 else
1479 kfree_skb(skb);
1480 skb = nskb;
1481 }
1482 return skb;
1483}
1484
1485/**
1486 * skb_peek - peek at the head of an &sk_buff_head
1487 * @list_: list to peek at
1488 *
1489 * Peek an &sk_buff. Unlike most other operations you _MUST_
1490 * be careful with this one. A peek leaves the buffer on the
1491 * list and someone else may run off with it. You must hold
1492 * the appropriate locks or have a private queue to do this.
1493 *
1494 * Returns %NULL for an empty list or a pointer to the head element.
1495 * The reference count is not incremented and the reference is therefore
1496 * volatile. Use with caution.
1497 */
1498static inline struct sk_buff *skb_peek(const struct sk_buff_head *list_)
1499{
1500 struct sk_buff *skb = list_->next;
1501
1502 if (skb == (struct sk_buff *)list_)
1503 skb = NULL;
1504 return skb;
1505}
1506
1507/**
1508 * skb_peek_next - peek skb following the given one from a queue
1509 * @skb: skb to start from
1510 * @list_: list to peek at
1511 *
1512 * Returns %NULL when the end of the list is met or a pointer to the
1513 * next element. The reference count is not incremented and the
1514 * reference is therefore volatile. Use with caution.
1515 */
1516static inline struct sk_buff *skb_peek_next(struct sk_buff *skb,
1517 const struct sk_buff_head *list_)
1518{
1519 struct sk_buff *next = skb->next;
1520
1521 if (next == (struct sk_buff *)list_)
1522 next = NULL;
1523 return next;
1524}
1525
1526/**
1527 * skb_peek_tail - peek at the tail of an &sk_buff_head
1528 * @list_: list to peek at
1529 *
1530 * Peek an &sk_buff. Unlike most other operations you _MUST_
1531 * be careful with this one. A peek leaves the buffer on the
1532 * list and someone else may run off with it. You must hold
1533 * the appropriate locks or have a private queue to do this.
1534 *
1535 * Returns %NULL for an empty list or a pointer to the tail element.
1536 * The reference count is not incremented and the reference is therefore
1537 * volatile. Use with caution.
1538 */
1539static inline struct sk_buff *skb_peek_tail(const struct sk_buff_head *list_)
1540{
1541 struct sk_buff *skb = list_->prev;
1542
1543 if (skb == (struct sk_buff *)list_)
1544 skb = NULL;
1545 return skb;
1546
1547}
1548
1549/**
1550 * skb_queue_len - get queue length
1551 * @list_: list to measure
1552 *
1553 * Return the length of an &sk_buff queue.
1554 */
1555static inline __u32 skb_queue_len(const struct sk_buff_head *list_)
1556{
1557 return list_->qlen;
1558}
1559
1560/**
1561 * __skb_queue_head_init - initialize non-spinlock portions of sk_buff_head
1562 * @list: queue to initialize
1563 *
1564 * This initializes only the list and queue length aspects of
1565 * an sk_buff_head object. This allows to initialize the list
1566 * aspects of an sk_buff_head without reinitializing things like
1567 * the spinlock. It can also be used for on-stack sk_buff_head
1568 * objects where the spinlock is known to not be used.
1569 */
1570static inline void __skb_queue_head_init(struct sk_buff_head *list)
1571{
1572 list->prev = list->next = (struct sk_buff *)list;
1573 list->qlen = 0;
1574}
1575
1576/*
1577 * This function creates a split out lock class for each invocation;
1578 * this is needed for now since a whole lot of users of the skb-queue
1579 * infrastructure in drivers have different locking usage (in hardirq)
1580 * than the networking core (in softirq only). In the long run either the
1581 * network layer or drivers should need annotation to consolidate the
1582 * main types of usage into 3 classes.
1583 */
1584static inline void skb_queue_head_init(struct sk_buff_head *list)
1585{
1586 spin_lock_init(&list->lock);
1587 __skb_queue_head_init(list);
1588}
1589
1590static inline void skb_queue_head_init_class(struct sk_buff_head *list,
1591 struct lock_class_key *class)
1592{
1593 skb_queue_head_init(list);
1594 lockdep_set_class(&list->lock, class);
1595}
1596
1597/*
1598 * Insert an sk_buff on a list.
1599 *
1600 * The "__skb_xxxx()" functions are the non-atomic ones that
1601 * can only be called with interrupts disabled.
1602 */
1603void skb_insert(struct sk_buff *old, struct sk_buff *newsk,
1604 struct sk_buff_head *list);
1605static inline void __skb_insert(struct sk_buff *newsk,
1606 struct sk_buff *prev, struct sk_buff *next,
1607 struct sk_buff_head *list)
1608{
1609 newsk->next = next;
1610 newsk->prev = prev;
1611 next->prev = prev->next = newsk;
1612 list->qlen++;
1613}
1614
1615static inline void __skb_queue_splice(const struct sk_buff_head *list,
1616 struct sk_buff *prev,
1617 struct sk_buff *next)
1618{
1619 struct sk_buff *first = list->next;
1620 struct sk_buff *last = list->prev;
1621
1622 first->prev = prev;
1623 prev->next = first;
1624
1625 last->next = next;
1626 next->prev = last;
1627}
1628
1629/**
1630 * skb_queue_splice - join two skb lists, this is designed for stacks
1631 * @list: the new list to add
1632 * @head: the place to add it in the first list
1633 */
1634static inline void skb_queue_splice(const struct sk_buff_head *list,
1635 struct sk_buff_head *head)
1636{
1637 if (!skb_queue_empty(list)) {
1638 __skb_queue_splice(list, (struct sk_buff *) head, head->next);
1639 head->qlen += list->qlen;
1640 }
1641}
1642
1643/**
1644 * skb_queue_splice_init - join two skb lists and reinitialise the emptied list
1645 * @list: the new list to add
1646 * @head: the place to add it in the first list
1647 *
1648 * The list at @list is reinitialised
1649 */
1650static inline void skb_queue_splice_init(struct sk_buff_head *list,
1651 struct sk_buff_head *head)
1652{
1653 if (!skb_queue_empty(list)) {
1654 __skb_queue_splice(list, (struct sk_buff *) head, head->next);
1655 head->qlen += list->qlen;
1656 __skb_queue_head_init(list);
1657 }
1658}
1659
1660/**
1661 * skb_queue_splice_tail - join two skb lists, each list being a queue
1662 * @list: the new list to add
1663 * @head: the place to add it in the first list
1664 */
1665static inline void skb_queue_splice_tail(const struct sk_buff_head *list,
1666 struct sk_buff_head *head)
1667{
1668 if (!skb_queue_empty(list)) {
1669 __skb_queue_splice(list, head->prev, (struct sk_buff *) head);
1670 head->qlen += list->qlen;
1671 }
1672}
1673
1674/**
1675 * skb_queue_splice_tail_init - join two skb lists and reinitialise the emptied list
1676 * @list: the new list to add
1677 * @head: the place to add it in the first list
1678 *
1679 * Each of the lists is a queue.
1680 * The list at @list is reinitialised
1681 */
1682static inline void skb_queue_splice_tail_init(struct sk_buff_head *list,
1683 struct sk_buff_head *head)
1684{
1685 if (!skb_queue_empty(list)) {
1686 __skb_queue_splice(list, head->prev, (struct sk_buff *) head);
1687 head->qlen += list->qlen;
1688 __skb_queue_head_init(list);
1689 }
1690}
1691
1692/**
1693 * __skb_queue_after - queue a buffer at the list head
1694 * @list: list to use
1695 * @prev: place after this buffer
1696 * @newsk: buffer to queue
1697 *
1698 * Queue a buffer int the middle of a list. This function takes no locks
1699 * and you must therefore hold required locks before calling it.
1700 *
1701 * A buffer cannot be placed on two lists at the same time.
1702 */
1703static inline void __skb_queue_after(struct sk_buff_head *list,
1704 struct sk_buff *prev,
1705 struct sk_buff *newsk)
1706{
1707 __skb_insert(newsk, prev, prev->next, list);
1708}
1709
1710void skb_append(struct sk_buff *old, struct sk_buff *newsk,
1711 struct sk_buff_head *list);
1712
1713static inline void __skb_queue_before(struct sk_buff_head *list,
1714 struct sk_buff *next,
1715 struct sk_buff *newsk)
1716{
1717 __skb_insert(newsk, next->prev, next, list);
1718}
1719
1720/**
1721 * __skb_queue_head - queue a buffer at the list head
1722 * @list: list to use
1723 * @newsk: buffer to queue
1724 *
1725 * Queue a buffer at the start of a list. This function takes no locks
1726 * and you must therefore hold required locks before calling it.
1727 *
1728 * A buffer cannot be placed on two lists at the same time.
1729 */
1730void skb_queue_head(struct sk_buff_head *list, struct sk_buff *newsk);
1731static inline void __skb_queue_head(struct sk_buff_head *list,
1732 struct sk_buff *newsk)
1733{
1734 __skb_queue_after(list, (struct sk_buff *)list, newsk);
1735}
1736
1737/**
1738 * __skb_queue_tail - queue a buffer at the list tail
1739 * @list: list to use
1740 * @newsk: buffer to queue
1741 *
1742 * Queue a buffer at the end of a list. This function takes no locks
1743 * and you must therefore hold required locks before calling it.
1744 *
1745 * A buffer cannot be placed on two lists at the same time.
1746 */
1747void skb_queue_tail(struct sk_buff_head *list, struct sk_buff *newsk);
1748static inline void __skb_queue_tail(struct sk_buff_head *list,
1749 struct sk_buff *newsk)
1750{
1751 __skb_queue_before(list, (struct sk_buff *)list, newsk);
1752}
1753
1754/*
1755 * remove sk_buff from list. _Must_ be called atomically, and with
1756 * the list known..
1757 */
1758void skb_unlink(struct sk_buff *skb, struct sk_buff_head *list);
1759static inline void __skb_unlink(struct sk_buff *skb, struct sk_buff_head *list)
1760{
1761 struct sk_buff *next, *prev;
1762
1763 list->qlen--;
1764 next = skb->next;
1765 prev = skb->prev;
1766 skb->next = skb->prev = NULL;
1767 next->prev = prev;
1768 prev->next = next;
1769}
1770
1771/**
1772 * __skb_dequeue - remove from the head of the queue
1773 * @list: list to dequeue from
1774 *
1775 * Remove the head of the list. This function does not take any locks
1776 * so must be used with appropriate locks held only. The head item is
1777 * returned or %NULL if the list is empty.
1778 */
1779struct sk_buff *skb_dequeue(struct sk_buff_head *list);
1780static inline struct sk_buff *__skb_dequeue(struct sk_buff_head *list)
1781{
1782 struct sk_buff *skb = skb_peek(list);
1783 if (skb)
1784 __skb_unlink(skb, list);
1785 return skb;
1786}
1787
1788/**
1789 * __skb_dequeue_tail - remove from the tail of the queue
1790 * @list: list to dequeue from
1791 *
1792 * Remove the tail of the list. This function does not take any locks
1793 * so must be used with appropriate locks held only. The tail item is
1794 * returned or %NULL if the list is empty.
1795 */
1796struct sk_buff *skb_dequeue_tail(struct sk_buff_head *list);
1797static inline struct sk_buff *__skb_dequeue_tail(struct sk_buff_head *list)
1798{
1799 struct sk_buff *skb = skb_peek_tail(list);
1800 if (skb)
1801 __skb_unlink(skb, list);
1802 return skb;
1803}
1804
1805
1806static inline bool skb_is_nonlinear(const struct sk_buff *skb)
1807{
1808 return skb->data_len;
1809}
1810
1811static inline unsigned int skb_headlen(const struct sk_buff *skb)
1812{
1813 return skb->len - skb->data_len;
1814}
1815
1816static inline unsigned int skb_pagelen(const struct sk_buff *skb)
1817{
1818 unsigned int i, len = 0;
1819
1820 for (i = skb_shinfo(skb)->nr_frags - 1; (int)i >= 0; i--)
1821 len += skb_frag_size(&skb_shinfo(skb)->frags[i]);
1822 return len + skb_headlen(skb);
1823}
1824
1825/**
1826 * __skb_fill_page_desc - initialise a paged fragment in an skb
1827 * @skb: buffer containing fragment to be initialised
1828 * @i: paged fragment index to initialise
1829 * @page: the page to use for this fragment
1830 * @off: the offset to the data with @page
1831 * @size: the length of the data
1832 *
1833 * Initialises the @i'th fragment of @skb to point to &size bytes at
1834 * offset @off within @page.
1835 *
1836 * Does not take any additional reference on the fragment.
1837 */
1838static inline void __skb_fill_page_desc(struct sk_buff *skb, int i,
1839 struct page *page, int off, int size)
1840{
1841 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
1842
1843 /*
1844 * Propagate page pfmemalloc to the skb if we can. The problem is
1845 * that not all callers have unique ownership of the page but rely
1846 * on page_is_pfmemalloc doing the right thing(tm).
1847 */
1848 frag->page.p = page;
1849 frag->page_offset = off;
1850 skb_frag_size_set(frag, size);
1851
1852 page = compound_head(page);
1853 if (page_is_pfmemalloc(page))
1854 skb->pfmemalloc = true;
1855}
1856
1857/**
1858 * skb_fill_page_desc - initialise a paged fragment in an skb
1859 * @skb: buffer containing fragment to be initialised
1860 * @i: paged fragment index to initialise
1861 * @page: the page to use for this fragment
1862 * @off: the offset to the data with @page
1863 * @size: the length of the data
1864 *
1865 * As per __skb_fill_page_desc() -- initialises the @i'th fragment of
1866 * @skb to point to @size bytes at offset @off within @page. In
1867 * addition updates @skb such that @i is the last fragment.
1868 *
1869 * Does not take any additional reference on the fragment.
1870 */
1871static inline void skb_fill_page_desc(struct sk_buff *skb, int i,
1872 struct page *page, int off, int size)
1873{
1874 __skb_fill_page_desc(skb, i, page, off, size);
1875 skb_shinfo(skb)->nr_frags = i + 1;
1876}
1877
1878void skb_add_rx_frag(struct sk_buff *skb, int i, struct page *page, int off,
1879 int size, unsigned int truesize);
1880
1881void skb_coalesce_rx_frag(struct sk_buff *skb, int i, int size,
1882 unsigned int truesize);
1883
1884#define SKB_PAGE_ASSERT(skb) BUG_ON(skb_shinfo(skb)->nr_frags)
1885#define SKB_FRAG_ASSERT(skb) BUG_ON(skb_has_frag_list(skb))
1886#define SKB_LINEAR_ASSERT(skb) BUG_ON(skb_is_nonlinear(skb))
1887
1888#ifdef NET_SKBUFF_DATA_USES_OFFSET
1889static inline unsigned char *skb_tail_pointer(const struct sk_buff *skb)
1890{
1891 return skb->head + skb->tail;
1892}
1893
1894static inline void skb_reset_tail_pointer(struct sk_buff *skb)
1895{
1896 skb->tail = skb->data - skb->head;
1897}
1898
1899static inline void skb_set_tail_pointer(struct sk_buff *skb, const int offset)
1900{
1901 skb_reset_tail_pointer(skb);
1902 skb->tail += offset;
1903}
1904
1905#else /* NET_SKBUFF_DATA_USES_OFFSET */
1906static inline unsigned char *skb_tail_pointer(const struct sk_buff *skb)
1907{
1908 return skb->tail;
1909}
1910
1911static inline void skb_reset_tail_pointer(struct sk_buff *skb)
1912{
1913 skb->tail = skb->data;
1914}
1915
1916static inline void skb_set_tail_pointer(struct sk_buff *skb, const int offset)
1917{
1918 skb->tail = skb->data + offset;
1919}
1920
1921#endif /* NET_SKBUFF_DATA_USES_OFFSET */
1922
1923/*
1924 * Add data to an sk_buff
1925 */
1926unsigned char *pskb_put(struct sk_buff *skb, struct sk_buff *tail, int len);
1927unsigned char *skb_put(struct sk_buff *skb, unsigned int len);
1928static inline unsigned char *__skb_put(struct sk_buff *skb, unsigned int len)
1929{
1930 unsigned char *tmp = skb_tail_pointer(skb);
1931 SKB_LINEAR_ASSERT(skb);
1932 skb->tail += len;
1933 skb->len += len;
1934 return tmp;
1935}
1936
1937unsigned char *skb_push(struct sk_buff *skb, unsigned int len);
1938static inline unsigned char *__skb_push(struct sk_buff *skb, unsigned int len)
1939{
1940 skb->data -= len;
1941 skb->len += len;
1942 return skb->data;
1943}
1944
1945unsigned char *skb_pull(struct sk_buff *skb, unsigned int len);
1946static inline unsigned char *__skb_pull(struct sk_buff *skb, unsigned int len)
1947{
1948 skb->len -= len;
1949 BUG_ON(skb->len < skb->data_len);
1950 return skb->data += len;
1951}
1952
1953static inline unsigned char *skb_pull_inline(struct sk_buff *skb, unsigned int len)
1954{
1955 return unlikely(len > skb->len) ? NULL : __skb_pull(skb, len);
1956}
1957
1958unsigned char *__pskb_pull_tail(struct sk_buff *skb, int delta);
1959
1960static inline unsigned char *__pskb_pull(struct sk_buff *skb, unsigned int len)
1961{
1962 if (len > skb_headlen(skb) &&
1963 !__pskb_pull_tail(skb, len - skb_headlen(skb)))
1964 return NULL;
1965 skb->len -= len;
1966 return skb->data += len;
1967}
1968
1969static inline unsigned char *pskb_pull(struct sk_buff *skb, unsigned int len)
1970{
1971 return unlikely(len > skb->len) ? NULL : __pskb_pull(skb, len);
1972}
1973
1974static inline int pskb_may_pull(struct sk_buff *skb, unsigned int len)
1975{
1976 if (likely(len <= skb_headlen(skb)))
1977 return 1;
1978 if (unlikely(len > skb->len))
1979 return 0;
1980 return __pskb_pull_tail(skb, len - skb_headlen(skb)) != NULL;
1981}
1982
1983void skb_condense(struct sk_buff *skb);
1984
1985/**
1986 * skb_headroom - bytes at buffer head
1987 * @skb: buffer to check
1988 *
1989 * Return the number of bytes of free space at the head of an &sk_buff.
1990 */
1991static inline unsigned int skb_headroom(const struct sk_buff *skb)
1992{
1993 return skb->data - skb->head;
1994}
1995
1996/**
1997 * skb_tailroom - bytes at buffer end
1998 * @skb: buffer to check
1999 *
2000 * Return the number of bytes of free space at the tail of an sk_buff
2001 */
2002static inline int skb_tailroom(const struct sk_buff *skb)
2003{
2004 return skb_is_nonlinear(skb) ? 0 : skb->end - skb->tail;
2005}
2006
2007/**
2008 * skb_availroom - bytes at buffer end
2009 * @skb: buffer to check
2010 *
2011 * Return the number of bytes of free space at the tail of an sk_buff
2012 * allocated by sk_stream_alloc()
2013 */
2014static inline int skb_availroom(const struct sk_buff *skb)
2015{
2016 if (skb_is_nonlinear(skb))
2017 return 0;
2018
2019 return skb->end - skb->tail - skb->reserved_tailroom;
2020}
2021
2022/**
2023 * skb_reserve - adjust headroom
2024 * @skb: buffer to alter
2025 * @len: bytes to move
2026 *
2027 * Increase the headroom of an empty &sk_buff by reducing the tail
2028 * room. This is only allowed for an empty buffer.
2029 */
2030static inline void skb_reserve(struct sk_buff *skb, int len)
2031{
2032 skb->data += len;
2033 skb->tail += len;
2034}
2035
2036/**
2037 * skb_tailroom_reserve - adjust reserved_tailroom
2038 * @skb: buffer to alter
2039 * @mtu: maximum amount of headlen permitted
2040 * @needed_tailroom: minimum amount of reserved_tailroom
2041 *
2042 * Set reserved_tailroom so that headlen can be as large as possible but
2043 * not larger than mtu and tailroom cannot be smaller than
2044 * needed_tailroom.
2045 * The required headroom should already have been reserved before using
2046 * this function.
2047 */
2048static inline void skb_tailroom_reserve(struct sk_buff *skb, unsigned int mtu,
2049 unsigned int needed_tailroom)
2050{
2051 SKB_LINEAR_ASSERT(skb);
2052 if (mtu < skb_tailroom(skb) - needed_tailroom)
2053 /* use at most mtu */
2054 skb->reserved_tailroom = skb_tailroom(skb) - mtu;
2055 else
2056 /* use up to all available space */
2057 skb->reserved_tailroom = needed_tailroom;
2058}
2059
2060#define ENCAP_TYPE_ETHER 0
2061#define ENCAP_TYPE_IPPROTO 1
2062
2063static inline void skb_set_inner_protocol(struct sk_buff *skb,
2064 __be16 protocol)
2065{
2066 skb->inner_protocol = protocol;
2067 skb->inner_protocol_type = ENCAP_TYPE_ETHER;
2068}
2069
2070static inline void skb_set_inner_ipproto(struct sk_buff *skb,
2071 __u8 ipproto)
2072{
2073 skb->inner_ipproto = ipproto;
2074 skb->inner_protocol_type = ENCAP_TYPE_IPPROTO;
2075}
2076
2077static inline void skb_reset_inner_headers(struct sk_buff *skb)
2078{
2079 skb->inner_mac_header = skb->mac_header;
2080 skb->inner_network_header = skb->network_header;
2081 skb->inner_transport_header = skb->transport_header;
2082}
2083
2084static inline void skb_reset_mac_len(struct sk_buff *skb)
2085{
2086 skb->mac_len = skb->network_header - skb->mac_header;
2087}
2088
2089static inline unsigned char *skb_inner_transport_header(const struct sk_buff
2090 *skb)
2091{
2092 return skb->head + skb->inner_transport_header;
2093}
2094
2095static inline int skb_inner_transport_offset(const struct sk_buff *skb)
2096{
2097 return skb_inner_transport_header(skb) - skb->data;
2098}
2099
2100static inline void skb_reset_inner_transport_header(struct sk_buff *skb)
2101{
2102 skb->inner_transport_header = skb->data - skb->head;
2103}
2104
2105static inline void skb_set_inner_transport_header(struct sk_buff *skb,
2106 const int offset)
2107{
2108 skb_reset_inner_transport_header(skb);
2109 skb->inner_transport_header += offset;
2110}
2111
2112static inline unsigned char *skb_inner_network_header(const struct sk_buff *skb)
2113{
2114 return skb->head + skb->inner_network_header;
2115}
2116
2117static inline void skb_reset_inner_network_header(struct sk_buff *skb)
2118{
2119 skb->inner_network_header = skb->data - skb->head;
2120}
2121
2122static inline void skb_set_inner_network_header(struct sk_buff *skb,
2123 const int offset)
2124{
2125 skb_reset_inner_network_header(skb);
2126 skb->inner_network_header += offset;
2127}
2128
2129static inline unsigned char *skb_inner_mac_header(const struct sk_buff *skb)
2130{
2131 return skb->head + skb->inner_mac_header;
2132}
2133
2134static inline void skb_reset_inner_mac_header(struct sk_buff *skb)
2135{
2136 skb->inner_mac_header = skb->data - skb->head;
2137}
2138
2139static inline void skb_set_inner_mac_header(struct sk_buff *skb,
2140 const int offset)
2141{
2142 skb_reset_inner_mac_header(skb);
2143 skb->inner_mac_header += offset;
2144}
2145static inline bool skb_transport_header_was_set(const struct sk_buff *skb)
2146{
2147 return skb->transport_header != (typeof(skb->transport_header))~0U;
2148}
2149
2150static inline unsigned char *skb_transport_header(const struct sk_buff *skb)
2151{
2152 return skb->head + skb->transport_header;
2153}
2154
2155static inline void skb_reset_transport_header(struct sk_buff *skb)
2156{
2157 skb->transport_header = skb->data - skb->head;
2158}
2159
2160static inline void skb_set_transport_header(struct sk_buff *skb,
2161 const int offset)
2162{
2163 skb_reset_transport_header(skb);
2164 skb->transport_header += offset;
2165}
2166
2167static inline unsigned char *skb_network_header(const struct sk_buff *skb)
2168{
2169 return skb->head + skb->network_header;
2170}
2171
2172static inline void skb_reset_network_header(struct sk_buff *skb)
2173{
2174 skb->network_header = skb->data - skb->head;
2175}
2176
2177static inline void skb_set_network_header(struct sk_buff *skb, const int offset)
2178{
2179 skb_reset_network_header(skb);
2180 skb->network_header += offset;
2181}
2182
2183static inline unsigned char *skb_mac_header(const struct sk_buff *skb)
2184{
2185 return skb->head + skb->mac_header;
2186}
2187
2188static inline int skb_mac_offset(const struct sk_buff *skb)
2189{
2190 return skb_mac_header(skb) - skb->data;
2191}
2192
2193static inline int skb_mac_header_was_set(const struct sk_buff *skb)
2194{
2195 return skb->mac_header != (typeof(skb->mac_header))~0U;
2196}
2197
2198static inline void skb_reset_mac_header(struct sk_buff *skb)
2199{
2200 skb->mac_header = skb->data - skb->head;
2201}
2202
2203static inline void skb_set_mac_header(struct sk_buff *skb, const int offset)
2204{
2205 skb_reset_mac_header(skb);
2206 skb->mac_header += offset;
2207}
2208
2209static inline void skb_pop_mac_header(struct sk_buff *skb)
2210{
2211 skb->mac_header = skb->network_header;
2212}
2213
2214static inline void skb_probe_transport_header(struct sk_buff *skb,
2215 const int offset_hint)
2216{
2217 struct flow_keys keys;
2218
2219 if (skb_transport_header_was_set(skb))
2220 return;
2221 else if (skb_flow_dissect_flow_keys(skb, &keys, 0))
2222 skb_set_transport_header(skb, keys.control.thoff);
2223 else
2224 skb_set_transport_header(skb, offset_hint);
2225}
2226
2227static inline void skb_mac_header_rebuild(struct sk_buff *skb)
2228{
2229 if (skb_mac_header_was_set(skb)) {
2230 const unsigned char *old_mac = skb_mac_header(skb);
2231
2232 skb_set_mac_header(skb, -skb->mac_len);
2233 memmove(skb_mac_header(skb), old_mac, skb->mac_len);
2234 }
2235}
2236
2237static inline int skb_checksum_start_offset(const struct sk_buff *skb)
2238{
2239 return skb->csum_start - skb_headroom(skb);
2240}
2241
2242static inline unsigned char *skb_checksum_start(const struct sk_buff *skb)
2243{
2244 return skb->head + skb->csum_start;
2245}
2246
2247static inline int skb_transport_offset(const struct sk_buff *skb)
2248{
2249 return skb_transport_header(skb) - skb->data;
2250}
2251
2252static inline u32 skb_network_header_len(const struct sk_buff *skb)
2253{
2254 return skb->transport_header - skb->network_header;
2255}
2256
2257static inline u32 skb_inner_network_header_len(const struct sk_buff *skb)
2258{
2259 return skb->inner_transport_header - skb->inner_network_header;
2260}
2261
2262static inline int skb_network_offset(const struct sk_buff *skb)
2263{
2264 return skb_network_header(skb) - skb->data;
2265}
2266
2267static inline int skb_inner_network_offset(const struct sk_buff *skb)
2268{
2269 return skb_inner_network_header(skb) - skb->data;
2270}
2271
2272static inline int pskb_network_may_pull(struct sk_buff *skb, unsigned int len)
2273{
2274 return pskb_may_pull(skb, skb_network_offset(skb) + len);
2275}
2276
2277/*
2278 * CPUs often take a performance hit when accessing unaligned memory
2279 * locations. The actual performance hit varies, it can be small if the
2280 * hardware handles it or large if we have to take an exception and fix it
2281 * in software.
2282 *
2283 * Since an ethernet header is 14 bytes network drivers often end up with
2284 * the IP header at an unaligned offset. The IP header can be aligned by
2285 * shifting the start of the packet by 2 bytes. Drivers should do this
2286 * with:
2287 *
2288 * skb_reserve(skb, NET_IP_ALIGN);
2289 *
2290 * The downside to this alignment of the IP header is that the DMA is now
2291 * unaligned. On some architectures the cost of an unaligned DMA is high
2292 * and this cost outweighs the gains made by aligning the IP header.
2293 *
2294 * Since this trade off varies between architectures, we allow NET_IP_ALIGN
2295 * to be overridden.
2296 */
2297#ifndef NET_IP_ALIGN
2298#define NET_IP_ALIGN 2
2299#endif
2300
2301/*
2302 * The networking layer reserves some headroom in skb data (via
2303 * dev_alloc_skb). This is used to avoid having to reallocate skb data when
2304 * the header has to grow. In the default case, if the header has to grow
2305 * 32 bytes or less we avoid the reallocation.
2306 *
2307 * Unfortunately this headroom changes the DMA alignment of the resulting
2308 * network packet. As for NET_IP_ALIGN, this unaligned DMA is expensive
2309 * on some architectures. An architecture can override this value,
2310 * perhaps setting it to a cacheline in size (since that will maintain
2311 * cacheline alignment of the DMA). It must be a power of 2.
2312 *
2313 * Various parts of the networking layer expect at least 32 bytes of
2314 * headroom, you should not reduce this.
2315 *
2316 * Using max(32, L1_CACHE_BYTES) makes sense (especially with RPS)
2317 * to reduce average number of cache lines per packet.
2318 * get_rps_cpus() for example only access one 64 bytes aligned block :
2319 * NET_IP_ALIGN(2) + ethernet_header(14) + IP_header(20/40) + ports(8)
2320 */
2321#ifndef NET_SKB_PAD
2322#define NET_SKB_PAD max(32, L1_CACHE_BYTES)
2323#endif
2324
2325int ___pskb_trim(struct sk_buff *skb, unsigned int len);
2326
2327static inline void __skb_set_length(struct sk_buff *skb, unsigned int len)
2328{
2329 if (unlikely(skb_is_nonlinear(skb))) {
2330 WARN_ON(1);
2331 return;
2332 }
2333 skb->len = len;
2334 skb_set_tail_pointer(skb, len);
2335}
2336
2337static inline void __skb_trim(struct sk_buff *skb, unsigned int len)
2338{
2339 __skb_set_length(skb, len);
2340}
2341
2342void skb_trim(struct sk_buff *skb, unsigned int len);
2343
2344static inline int __pskb_trim(struct sk_buff *skb, unsigned int len)
2345{
2346 if (skb->data_len)
2347 return ___pskb_trim(skb, len);
2348 __skb_trim(skb, len);
2349 return 0;
2350}
2351
2352static inline int pskb_trim(struct sk_buff *skb, unsigned int len)
2353{
2354 return (len < skb->len) ? __pskb_trim(skb, len) : 0;
2355}
2356
2357/**
2358 * pskb_trim_unique - remove end from a paged unique (not cloned) buffer
2359 * @skb: buffer to alter
2360 * @len: new length
2361 *
2362 * This is identical to pskb_trim except that the caller knows that
2363 * the skb is not cloned so we should never get an error due to out-
2364 * of-memory.
2365 */
2366static inline void pskb_trim_unique(struct sk_buff *skb, unsigned int len)
2367{
2368 int err = pskb_trim(skb, len);
2369 BUG_ON(err);
2370}
2371
2372static inline int __skb_grow(struct sk_buff *skb, unsigned int len)
2373{
2374 unsigned int diff = len - skb->len;
2375
2376 if (skb_tailroom(skb) < diff) {
2377 int ret = pskb_expand_head(skb, 0, diff - skb_tailroom(skb),
2378 GFP_ATOMIC);
2379 if (ret)
2380 return ret;
2381 }
2382 __skb_set_length(skb, len);
2383 return 0;
2384}
2385
2386/**
2387 * skb_orphan - orphan a buffer
2388 * @skb: buffer to orphan
2389 *
2390 * If a buffer currently has an owner then we call the owner's
2391 * destructor function and make the @skb unowned. The buffer continues
2392 * to exist but is no longer charged to its former owner.
2393 */
2394static inline void skb_orphan(struct sk_buff *skb)
2395{
2396 if (skb->destructor) {
2397 skb->destructor(skb);
2398 skb->destructor = NULL;
2399 skb->sk = NULL;
2400 } else {
2401 BUG_ON(skb->sk);
2402 }
2403}
2404
2405/**
2406 * skb_orphan_frags - orphan the frags contained in a buffer
2407 * @skb: buffer to orphan frags from
2408 * @gfp_mask: allocation mask for replacement pages
2409 *
2410 * For each frag in the SKB which needs a destructor (i.e. has an
2411 * owner) create a copy of that frag and release the original
2412 * page by calling the destructor.
2413 */
2414static inline int skb_orphan_frags(struct sk_buff *skb, gfp_t gfp_mask)
2415{
2416 if (likely(!(skb_shinfo(skb)->tx_flags & SKBTX_DEV_ZEROCOPY)))
2417 return 0;
2418 return skb_copy_ubufs(skb, gfp_mask);
2419}
2420
2421/**
2422 * __skb_queue_purge - empty a list
2423 * @list: list to empty
2424 *
2425 * Delete all buffers on an &sk_buff list. Each buffer is removed from
2426 * the list and one reference dropped. This function does not take the
2427 * list lock and the caller must hold the relevant locks to use it.
2428 */
2429void skb_queue_purge(struct sk_buff_head *list);
2430static inline void __skb_queue_purge(struct sk_buff_head *list)
2431{
2432 struct sk_buff *skb;
2433 while ((skb = __skb_dequeue(list)) != NULL)
2434 kfree_skb(skb);
2435}
2436
2437void skb_rbtree_purge(struct rb_root *root);
2438
2439void *netdev_alloc_frag(unsigned int fragsz);
2440
2441struct sk_buff *__netdev_alloc_skb(struct net_device *dev, unsigned int length,
2442 gfp_t gfp_mask);
2443
2444/**
2445 * netdev_alloc_skb - allocate an skbuff for rx on a specific device
2446 * @dev: network device to receive on
2447 * @length: length to allocate
2448 *
2449 * Allocate a new &sk_buff and assign it a usage count of one. The
2450 * buffer has unspecified headroom built in. Users should allocate
2451 * the headroom they think they need without accounting for the
2452 * built in space. The built in space is used for optimisations.
2453 *
2454 * %NULL is returned if there is no free memory. Although this function
2455 * allocates memory it can be called from an interrupt.
2456 */
2457static inline struct sk_buff *netdev_alloc_skb(struct net_device *dev,
2458 unsigned int length)
2459{
2460 return __netdev_alloc_skb(dev, length, GFP_ATOMIC);
2461}
2462
2463/* legacy helper around __netdev_alloc_skb() */
2464static inline struct sk_buff *__dev_alloc_skb(unsigned int length,
2465 gfp_t gfp_mask)
2466{
2467 return __netdev_alloc_skb(NULL, length, gfp_mask);
2468}
2469
2470/* legacy helper around netdev_alloc_skb() */
2471static inline struct sk_buff *dev_alloc_skb(unsigned int length)
2472{
2473 return netdev_alloc_skb(NULL, length);
2474}
2475
2476
2477static inline struct sk_buff *__netdev_alloc_skb_ip_align(struct net_device *dev,
2478 unsigned int length, gfp_t gfp)
2479{
2480 struct sk_buff *skb = __netdev_alloc_skb(dev, length + NET_IP_ALIGN, gfp);
2481
2482 if (NET_IP_ALIGN && skb)
2483 skb_reserve(skb, NET_IP_ALIGN);
2484 return skb;
2485}
2486
2487static inline struct sk_buff *netdev_alloc_skb_ip_align(struct net_device *dev,
2488 unsigned int length)
2489{
2490 return __netdev_alloc_skb_ip_align(dev, length, GFP_ATOMIC);
2491}
2492
2493static inline void skb_free_frag(void *addr)
2494{
2495 page_frag_free(addr);
2496}
2497
2498void *napi_alloc_frag(unsigned int fragsz);
2499struct sk_buff *__napi_alloc_skb(struct napi_struct *napi,
2500 unsigned int length, gfp_t gfp_mask);
2501static inline struct sk_buff *napi_alloc_skb(struct napi_struct *napi,
2502 unsigned int length)
2503{
2504 return __napi_alloc_skb(napi, length, GFP_ATOMIC);
2505}
2506void napi_consume_skb(struct sk_buff *skb, int budget);
2507
2508void __kfree_skb_flush(void);
2509void __kfree_skb_defer(struct sk_buff *skb);
2510
2511/**
2512 * __dev_alloc_pages - allocate page for network Rx
2513 * @gfp_mask: allocation priority. Set __GFP_NOMEMALLOC if not for network Rx
2514 * @order: size of the allocation
2515 *
2516 * Allocate a new page.
2517 *
2518 * %NULL is returned if there is no free memory.
2519*/
2520static inline struct page *__dev_alloc_pages(gfp_t gfp_mask,
2521 unsigned int order)
2522{
2523 /* This piece of code contains several assumptions.
2524 * 1. This is for device Rx, therefor a cold page is preferred.
2525 * 2. The expectation is the user wants a compound page.
2526 * 3. If requesting a order 0 page it will not be compound
2527 * due to the check to see if order has a value in prep_new_page
2528 * 4. __GFP_MEMALLOC is ignored if __GFP_NOMEMALLOC is set due to
2529 * code in gfp_to_alloc_flags that should be enforcing this.
2530 */
2531 gfp_mask |= __GFP_COLD | __GFP_COMP | __GFP_MEMALLOC;
2532
2533 return alloc_pages_node(NUMA_NO_NODE, gfp_mask, order);
2534}
2535
2536static inline struct page *dev_alloc_pages(unsigned int order)
2537{
2538 return __dev_alloc_pages(GFP_ATOMIC | __GFP_NOWARN, order);
2539}
2540
2541/**
2542 * __dev_alloc_page - allocate a page for network Rx
2543 * @gfp_mask: allocation priority. Set __GFP_NOMEMALLOC if not for network Rx
2544 *
2545 * Allocate a new page.
2546 *
2547 * %NULL is returned if there is no free memory.
2548 */
2549static inline struct page *__dev_alloc_page(gfp_t gfp_mask)
2550{
2551 return __dev_alloc_pages(gfp_mask, 0);
2552}
2553
2554static inline struct page *dev_alloc_page(void)
2555{
2556 return dev_alloc_pages(0);
2557}
2558
2559/**
2560 * skb_propagate_pfmemalloc - Propagate pfmemalloc if skb is allocated after RX page
2561 * @page: The page that was allocated from skb_alloc_page
2562 * @skb: The skb that may need pfmemalloc set
2563 */
2564static inline void skb_propagate_pfmemalloc(struct page *page,
2565 struct sk_buff *skb)
2566{
2567 if (page_is_pfmemalloc(page))
2568 skb->pfmemalloc = true;
2569}
2570
2571/**
2572 * skb_frag_page - retrieve the page referred to by a paged fragment
2573 * @frag: the paged fragment
2574 *
2575 * Returns the &struct page associated with @frag.
2576 */
2577static inline struct page *skb_frag_page(const skb_frag_t *frag)
2578{
2579 return frag->page.p;
2580}
2581
2582/**
2583 * __skb_frag_ref - take an addition reference on a paged fragment.
2584 * @frag: the paged fragment
2585 *
2586 * Takes an additional reference on the paged fragment @frag.
2587 */
2588static inline void __skb_frag_ref(skb_frag_t *frag)
2589{
2590 get_page(skb_frag_page(frag));
2591}
2592
2593/**
2594 * skb_frag_ref - take an addition reference on a paged fragment of an skb.
2595 * @skb: the buffer
2596 * @f: the fragment offset.
2597 *
2598 * Takes an additional reference on the @f'th paged fragment of @skb.
2599 */
2600static inline void skb_frag_ref(struct sk_buff *skb, int f)
2601{
2602 __skb_frag_ref(&skb_shinfo(skb)->frags[f]);
2603}
2604
2605/**
2606 * __skb_frag_unref - release a reference on a paged fragment.
2607 * @frag: the paged fragment
2608 *
2609 * Releases a reference on the paged fragment @frag.
2610 */
2611static inline void __skb_frag_unref(skb_frag_t *frag)
2612{
2613 put_page(skb_frag_page(frag));
2614}
2615
2616/**
2617 * skb_frag_unref - release a reference on a paged fragment of an skb.
2618 * @skb: the buffer
2619 * @f: the fragment offset
2620 *
2621 * Releases a reference on the @f'th paged fragment of @skb.
2622 */
2623static inline void skb_frag_unref(struct sk_buff *skb, int f)
2624{
2625 __skb_frag_unref(&skb_shinfo(skb)->frags[f]);
2626}
2627
2628/**
2629 * skb_frag_address - gets the address of the data contained in a paged fragment
2630 * @frag: the paged fragment buffer
2631 *
2632 * Returns the address of the data within @frag. The page must already
2633 * be mapped.
2634 */
2635static inline void *skb_frag_address(const skb_frag_t *frag)
2636{
2637 return page_address(skb_frag_page(frag)) + frag->page_offset;
2638}
2639
2640/**
2641 * skb_frag_address_safe - gets the address of the data contained in a paged fragment
2642 * @frag: the paged fragment buffer
2643 *
2644 * Returns the address of the data within @frag. Checks that the page
2645 * is mapped and returns %NULL otherwise.
2646 */
2647static inline void *skb_frag_address_safe(const skb_frag_t *frag)
2648{
2649 void *ptr = page_address(skb_frag_page(frag));
2650 if (unlikely(!ptr))
2651 return NULL;
2652
2653 return ptr + frag->page_offset;
2654}
2655
2656/**
2657 * __skb_frag_set_page - sets the page contained in a paged fragment
2658 * @frag: the paged fragment
2659 * @page: the page to set
2660 *
2661 * Sets the fragment @frag to contain @page.
2662 */
2663static inline void __skb_frag_set_page(skb_frag_t *frag, struct page *page)
2664{
2665 frag->page.p = page;
2666}
2667
2668/**
2669 * skb_frag_set_page - sets the page contained in a paged fragment of an skb
2670 * @skb: the buffer
2671 * @f: the fragment offset
2672 * @page: the page to set
2673 *
2674 * Sets the @f'th fragment of @skb to contain @page.
2675 */
2676static inline void skb_frag_set_page(struct sk_buff *skb, int f,
2677 struct page *page)
2678{
2679 __skb_frag_set_page(&skb_shinfo(skb)->frags[f], page);
2680}
2681
2682bool skb_page_frag_refill(unsigned int sz, struct page_frag *pfrag, gfp_t prio);
2683
2684/**
2685 * skb_frag_dma_map - maps a paged fragment via the DMA API
2686 * @dev: the device to map the fragment to
2687 * @frag: the paged fragment to map
2688 * @offset: the offset within the fragment (starting at the
2689 * fragment's own offset)
2690 * @size: the number of bytes to map
2691 * @dir: the direction of the mapping (%PCI_DMA_*)
2692 *
2693 * Maps the page associated with @frag to @device.
2694 */
2695static inline dma_addr_t skb_frag_dma_map(struct device *dev,
2696 const skb_frag_t *frag,
2697 size_t offset, size_t size,
2698 enum dma_data_direction dir)
2699{
2700 return dma_map_page(dev, skb_frag_page(frag),
2701 frag->page_offset + offset, size, dir);
2702}
2703
2704static inline struct sk_buff *pskb_copy(struct sk_buff *skb,
2705 gfp_t gfp_mask)
2706{
2707 return __pskb_copy(skb, skb_headroom(skb), gfp_mask);
2708}
2709
2710
2711static inline struct sk_buff *pskb_copy_for_clone(struct sk_buff *skb,
2712 gfp_t gfp_mask)
2713{
2714 return __pskb_copy_fclone(skb, skb_headroom(skb), gfp_mask, true);
2715}
2716
2717
2718/**
2719 * skb_clone_writable - is the header of a clone writable
2720 * @skb: buffer to check
2721 * @len: length up to which to write
2722 *
2723 * Returns true if modifying the header part of the cloned buffer
2724 * does not requires the data to be copied.
2725 */
2726static inline int skb_clone_writable(const struct sk_buff *skb, unsigned int len)
2727{
2728 return !skb_header_cloned(skb) &&
2729 skb_headroom(skb) + len <= skb->hdr_len;
2730}
2731
2732static inline int skb_try_make_writable(struct sk_buff *skb,
2733 unsigned int write_len)
2734{
2735 return skb_cloned(skb) && !skb_clone_writable(skb, write_len) &&
2736 pskb_expand_head(skb, 0, 0, GFP_ATOMIC);
2737}
2738
2739static inline int __skb_cow(struct sk_buff *skb, unsigned int headroom,
2740 int cloned)
2741{
2742 int delta = 0;
2743
2744 if (headroom > skb_headroom(skb))
2745 delta = headroom - skb_headroom(skb);
2746
2747 if (delta || cloned)
2748 return pskb_expand_head(skb, ALIGN(delta, NET_SKB_PAD), 0,
2749 GFP_ATOMIC);
2750 return 0;
2751}
2752
2753/**
2754 * skb_cow - copy header of skb when it is required
2755 * @skb: buffer to cow
2756 * @headroom: needed headroom
2757 *
2758 * If the skb passed lacks sufficient headroom or its data part
2759 * is shared, data is reallocated. If reallocation fails, an error
2760 * is returned and original skb is not changed.
2761 *
2762 * The result is skb with writable area skb->head...skb->tail
2763 * and at least @headroom of space at head.
2764 */
2765static inline int skb_cow(struct sk_buff *skb, unsigned int headroom)
2766{
2767 return __skb_cow(skb, headroom, skb_cloned(skb));
2768}
2769
2770/**
2771 * skb_cow_head - skb_cow but only making the head writable
2772 * @skb: buffer to cow
2773 * @headroom: needed headroom
2774 *
2775 * This function is identical to skb_cow except that we replace the
2776 * skb_cloned check by skb_header_cloned. It should be used when
2777 * you only need to push on some header and do not need to modify
2778 * the data.
2779 */
2780static inline int skb_cow_head(struct sk_buff *skb, unsigned int headroom)
2781{
2782 return __skb_cow(skb, headroom, skb_header_cloned(skb));
2783}
2784
2785/**
2786 * skb_padto - pad an skbuff up to a minimal size
2787 * @skb: buffer to pad
2788 * @len: minimal length
2789 *
2790 * Pads up a buffer to ensure the trailing bytes exist and are
2791 * blanked. If the buffer already contains sufficient data it
2792 * is untouched. Otherwise it is extended. Returns zero on
2793 * success. The skb is freed on error.
2794 */
2795static inline int skb_padto(struct sk_buff *skb, unsigned int len)
2796{
2797 unsigned int size = skb->len;
2798 if (likely(size >= len))
2799 return 0;
2800 return skb_pad(skb, len - size);
2801}
2802
2803/**
2804 * skb_put_padto - increase size and pad an skbuff up to a minimal size
2805 * @skb: buffer to pad
2806 * @len: minimal length
2807 *
2808 * Pads up a buffer to ensure the trailing bytes exist and are
2809 * blanked. If the buffer already contains sufficient data it
2810 * is untouched. Otherwise it is extended. Returns zero on
2811 * success. The skb is freed on error.
2812 */
2813static inline int skb_put_padto(struct sk_buff *skb, unsigned int len)
2814{
2815 unsigned int size = skb->len;
2816
2817 if (unlikely(size < len)) {
2818 len -= size;
2819 if (skb_pad(skb, len))
2820 return -ENOMEM;
2821 __skb_put(skb, len);
2822 }
2823 return 0;
2824}
2825
2826static inline int skb_add_data(struct sk_buff *skb,
2827 struct iov_iter *from, int copy)
2828{
2829 const int off = skb->len;
2830
2831 if (skb->ip_summed == CHECKSUM_NONE) {
2832 __wsum csum = 0;
2833 if (csum_and_copy_from_iter_full(skb_put(skb, copy), copy,
2834 &csum, from)) {
2835 skb->csum = csum_block_add(skb->csum, csum, off);
2836 return 0;
2837 }
2838 } else if (copy_from_iter_full(skb_put(skb, copy), copy, from))
2839 return 0;
2840
2841 __skb_trim(skb, off);
2842 return -EFAULT;
2843}
2844
2845static inline bool skb_can_coalesce(struct sk_buff *skb, int i,
2846 const struct page *page, int off)
2847{
2848 if (i) {
2849 const struct skb_frag_struct *frag = &skb_shinfo(skb)->frags[i - 1];
2850
2851 return page == skb_frag_page(frag) &&
2852 off == frag->page_offset + skb_frag_size(frag);
2853 }
2854 return false;
2855}
2856
2857static inline int __skb_linearize(struct sk_buff *skb)
2858{
2859 return __pskb_pull_tail(skb, skb->data_len) ? 0 : -ENOMEM;
2860}
2861
2862/**
2863 * skb_linearize - convert paged skb to linear one
2864 * @skb: buffer to linarize
2865 *
2866 * If there is no free memory -ENOMEM is returned, otherwise zero
2867 * is returned and the old skb data released.
2868 */
2869static inline int skb_linearize(struct sk_buff *skb)
2870{
2871 return skb_is_nonlinear(skb) ? __skb_linearize(skb) : 0;
2872}
2873
2874/**
2875 * skb_has_shared_frag - can any frag be overwritten
2876 * @skb: buffer to test
2877 *
2878 * Return true if the skb has at least one frag that might be modified
2879 * by an external entity (as in vmsplice()/sendfile())
2880 */
2881static inline bool skb_has_shared_frag(const struct sk_buff *skb)
2882{
2883 return skb_is_nonlinear(skb) &&
2884 skb_shinfo(skb)->tx_flags & SKBTX_SHARED_FRAG;
2885}
2886
2887/**
2888 * skb_linearize_cow - make sure skb is linear and writable
2889 * @skb: buffer to process
2890 *
2891 * If there is no free memory -ENOMEM is returned, otherwise zero
2892 * is returned and the old skb data released.
2893 */
2894static inline int skb_linearize_cow(struct sk_buff *skb)
2895{
2896 return skb_is_nonlinear(skb) || skb_cloned(skb) ?
2897 __skb_linearize(skb) : 0;
2898}
2899
2900static __always_inline void
2901__skb_postpull_rcsum(struct sk_buff *skb, const void *start, unsigned int len,
2902 unsigned int off)
2903{
2904 if (skb->ip_summed == CHECKSUM_COMPLETE)
2905 skb->csum = csum_block_sub(skb->csum,
2906 csum_partial(start, len, 0), off);
2907 else if (skb->ip_summed == CHECKSUM_PARTIAL &&
2908 skb_checksum_start_offset(skb) < 0)
2909 skb->ip_summed = CHECKSUM_NONE;
2910}
2911
2912/**
2913 * skb_postpull_rcsum - update checksum for received skb after pull
2914 * @skb: buffer to update
2915 * @start: start of data before pull
2916 * @len: length of data pulled
2917 *
2918 * After doing a pull on a received packet, you need to call this to
2919 * update the CHECKSUM_COMPLETE checksum, or set ip_summed to
2920 * CHECKSUM_NONE so that it can be recomputed from scratch.
2921 */
2922static inline void skb_postpull_rcsum(struct sk_buff *skb,
2923 const void *start, unsigned int len)
2924{
2925 __skb_postpull_rcsum(skb, start, len, 0);
2926}
2927
2928static __always_inline void
2929__skb_postpush_rcsum(struct sk_buff *skb, const void *start, unsigned int len,
2930 unsigned int off)
2931{
2932 if (skb->ip_summed == CHECKSUM_COMPLETE)
2933 skb->csum = csum_block_add(skb->csum,
2934 csum_partial(start, len, 0), off);
2935}
2936
2937/**
2938 * skb_postpush_rcsum - update checksum for received skb after push
2939 * @skb: buffer to update
2940 * @start: start of data after push
2941 * @len: length of data pushed
2942 *
2943 * After doing a push on a received packet, you need to call this to
2944 * update the CHECKSUM_COMPLETE checksum.
2945 */
2946static inline void skb_postpush_rcsum(struct sk_buff *skb,
2947 const void *start, unsigned int len)
2948{
2949 __skb_postpush_rcsum(skb, start, len, 0);
2950}
2951
2952unsigned char *skb_pull_rcsum(struct sk_buff *skb, unsigned int len);
2953
2954/**
2955 * skb_push_rcsum - push skb and update receive checksum
2956 * @skb: buffer to update
2957 * @len: length of data pulled
2958 *
2959 * This function performs an skb_push on the packet and updates
2960 * the CHECKSUM_COMPLETE checksum. It should be used on
2961 * receive path processing instead of skb_push unless you know
2962 * that the checksum difference is zero (e.g., a valid IP header)
2963 * or you are setting ip_summed to CHECKSUM_NONE.
2964 */
2965static inline unsigned char *skb_push_rcsum(struct sk_buff *skb,
2966 unsigned int len)
2967{
2968 skb_push(skb, len);
2969 skb_postpush_rcsum(skb, skb->data, len);
2970 return skb->data;
2971}
2972
2973/**
2974 * pskb_trim_rcsum - trim received skb and update checksum
2975 * @skb: buffer to trim
2976 * @len: new length
2977 *
2978 * This is exactly the same as pskb_trim except that it ensures the
2979 * checksum of received packets are still valid after the operation.
2980 */
2981
2982static inline int pskb_trim_rcsum(struct sk_buff *skb, unsigned int len)
2983{
2984 if (likely(len >= skb->len))
2985 return 0;
2986 if (skb->ip_summed == CHECKSUM_COMPLETE)
2987 skb->ip_summed = CHECKSUM_NONE;
2988 return __pskb_trim(skb, len);
2989}
2990
2991static inline int __skb_trim_rcsum(struct sk_buff *skb, unsigned int len)
2992{
2993 if (skb->ip_summed == CHECKSUM_COMPLETE)
2994 skb->ip_summed = CHECKSUM_NONE;
2995 __skb_trim(skb, len);
2996 return 0;
2997}
2998
2999static inline int __skb_grow_rcsum(struct sk_buff *skb, unsigned int len)
3000{
3001 if (skb->ip_summed == CHECKSUM_COMPLETE)
3002 skb->ip_summed = CHECKSUM_NONE;
3003 return __skb_grow(skb, len);
3004}
3005
3006#define skb_queue_walk(queue, skb) \
3007 for (skb = (queue)->next; \
3008 skb != (struct sk_buff *)(queue); \
3009 skb = skb->next)
3010
3011#define skb_queue_walk_safe(queue, skb, tmp) \
3012 for (skb = (queue)->next, tmp = skb->next; \
3013 skb != (struct sk_buff *)(queue); \
3014 skb = tmp, tmp = skb->next)
3015
3016#define skb_queue_walk_from(queue, skb) \
3017 for (; skb != (struct sk_buff *)(queue); \
3018 skb = skb->next)
3019
3020#define skb_queue_walk_from_safe(queue, skb, tmp) \
3021 for (tmp = skb->next; \
3022 skb != (struct sk_buff *)(queue); \
3023 skb = tmp, tmp = skb->next)
3024
3025#define skb_queue_reverse_walk(queue, skb) \
3026 for (skb = (queue)->prev; \
3027 skb != (struct sk_buff *)(queue); \
3028 skb = skb->prev)
3029
3030#define skb_queue_reverse_walk_safe(queue, skb, tmp) \
3031 for (skb = (queue)->prev, tmp = skb->prev; \
3032 skb != (struct sk_buff *)(queue); \
3033 skb = tmp, tmp = skb->prev)
3034
3035#define skb_queue_reverse_walk_from_safe(queue, skb, tmp) \
3036 for (tmp = skb->prev; \
3037 skb != (struct sk_buff *)(queue); \
3038 skb = tmp, tmp = skb->prev)
3039
3040static inline bool skb_has_frag_list(const struct sk_buff *skb)
3041{
3042 return skb_shinfo(skb)->frag_list != NULL;
3043}
3044
3045static inline void skb_frag_list_init(struct sk_buff *skb)
3046{
3047 skb_shinfo(skb)->frag_list = NULL;
3048}
3049
3050#define skb_walk_frags(skb, iter) \
3051 for (iter = skb_shinfo(skb)->frag_list; iter; iter = iter->next)
3052
3053
3054int __skb_wait_for_more_packets(struct sock *sk, int *err, long *timeo_p,
3055 const struct sk_buff *skb);
3056struct sk_buff *__skb_try_recv_datagram(struct sock *sk, unsigned flags,
3057 void (*destructor)(struct sock *sk,
3058 struct sk_buff *skb),
3059 int *peeked, int *off, int *err,
3060 struct sk_buff **last);
3061struct sk_buff *__skb_recv_datagram(struct sock *sk, unsigned flags,
3062 void (*destructor)(struct sock *sk,
3063 struct sk_buff *skb),
3064 int *peeked, int *off, int *err);
3065struct sk_buff *skb_recv_datagram(struct sock *sk, unsigned flags, int noblock,
3066 int *err);
3067unsigned int datagram_poll(struct file *file, struct socket *sock,
3068 struct poll_table_struct *wait);
3069int skb_copy_datagram_iter(const struct sk_buff *from, int offset,
3070 struct iov_iter *to, int size);
3071static inline int skb_copy_datagram_msg(const struct sk_buff *from, int offset,
3072 struct msghdr *msg, int size)
3073{
3074 return skb_copy_datagram_iter(from, offset, &msg->msg_iter, size);
3075}
3076int skb_copy_and_csum_datagram_msg(struct sk_buff *skb, int hlen,
3077 struct msghdr *msg);
3078int skb_copy_datagram_from_iter(struct sk_buff *skb, int offset,
3079 struct iov_iter *from, int len);
3080int zerocopy_sg_from_iter(struct sk_buff *skb, struct iov_iter *frm);
3081void skb_free_datagram(struct sock *sk, struct sk_buff *skb);
3082void __skb_free_datagram_locked(struct sock *sk, struct sk_buff *skb, int len);
3083static inline void skb_free_datagram_locked(struct sock *sk,
3084 struct sk_buff *skb)
3085{
3086 __skb_free_datagram_locked(sk, skb, 0);
3087}
3088int skb_kill_datagram(struct sock *sk, struct sk_buff *skb, unsigned int flags);
3089int skb_copy_bits(const struct sk_buff *skb, int offset, void *to, int len);
3090int skb_store_bits(struct sk_buff *skb, int offset, const void *from, int len);
3091__wsum skb_copy_and_csum_bits(const struct sk_buff *skb, int offset, u8 *to,
3092 int len, __wsum csum);
3093int skb_splice_bits(struct sk_buff *skb, struct sock *sk, unsigned int offset,
3094 struct pipe_inode_info *pipe, unsigned int len,
3095 unsigned int flags);
3096void skb_copy_and_csum_dev(const struct sk_buff *skb, u8 *to);
3097unsigned int skb_zerocopy_headlen(const struct sk_buff *from);
3098int skb_zerocopy(struct sk_buff *to, struct sk_buff *from,
3099 int len, int hlen);
3100void skb_split(struct sk_buff *skb, struct sk_buff *skb1, const u32 len);
3101int skb_shift(struct sk_buff *tgt, struct sk_buff *skb, int shiftlen);
3102void skb_scrub_packet(struct sk_buff *skb, bool xnet);
3103unsigned int skb_gso_transport_seglen(const struct sk_buff *skb);
3104bool skb_gso_validate_mtu(const struct sk_buff *skb, unsigned int mtu);
3105struct sk_buff *skb_segment(struct sk_buff *skb, netdev_features_t features);
3106struct sk_buff *skb_vlan_untag(struct sk_buff *skb);
3107int skb_ensure_writable(struct sk_buff *skb, int write_len);
3108int __skb_vlan_pop(struct sk_buff *skb, u16 *vlan_tci);
3109int skb_vlan_pop(struct sk_buff *skb);
3110int skb_vlan_push(struct sk_buff *skb, __be16 vlan_proto, u16 vlan_tci);
3111struct sk_buff *pskb_extract(struct sk_buff *skb, int off, int to_copy,
3112 gfp_t gfp);
3113
3114static inline int memcpy_from_msg(void *data, struct msghdr *msg, int len)
3115{
3116 return copy_from_iter(data, len, &msg->msg_iter) == len ? 0 : -EFAULT;
3117}
3118
3119static inline int memcpy_to_msg(struct msghdr *msg, void *data, int len)
3120{
3121 return copy_to_iter(data, len, &msg->msg_iter) == len ? 0 : -EFAULT;
3122}
3123
3124struct skb_checksum_ops {
3125 __wsum (*update)(const void *mem, int len, __wsum wsum);
3126 __wsum (*combine)(__wsum csum, __wsum csum2, int offset, int len);
3127};
3128
3129__wsum __skb_checksum(const struct sk_buff *skb, int offset, int len,
3130 __wsum csum, const struct skb_checksum_ops *ops);
3131__wsum skb_checksum(const struct sk_buff *skb, int offset, int len,
3132 __wsum csum);
3133
3134static inline void * __must_check
3135__skb_header_pointer(const struct sk_buff *skb, int offset,
3136 int len, void *data, int hlen, void *buffer)
3137{
3138 if (hlen - offset >= len)
3139 return data + offset;
3140
3141 if (!skb ||
3142 skb_copy_bits(skb, offset, buffer, len) < 0)
3143 return NULL;
3144
3145 return buffer;
3146}
3147
3148static inline void * __must_check
3149skb_header_pointer(const struct sk_buff *skb, int offset, int len, void *buffer)
3150{
3151 return __skb_header_pointer(skb, offset, len, skb->data,
3152 skb_headlen(skb), buffer);
3153}
3154
3155/**
3156 * skb_needs_linearize - check if we need to linearize a given skb
3157 * depending on the given device features.
3158 * @skb: socket buffer to check
3159 * @features: net device features
3160 *
3161 * Returns true if either:
3162 * 1. skb has frag_list and the device doesn't support FRAGLIST, or
3163 * 2. skb is fragmented and the device does not support SG.
3164 */
3165static inline bool skb_needs_linearize(struct sk_buff *skb,
3166 netdev_features_t features)
3167{
3168 return skb_is_nonlinear(skb) &&
3169 ((skb_has_frag_list(skb) && !(features & NETIF_F_FRAGLIST)) ||
3170 (skb_shinfo(skb)->nr_frags && !(features & NETIF_F_SG)));
3171}
3172
3173static inline void skb_copy_from_linear_data(const struct sk_buff *skb,
3174 void *to,
3175 const unsigned int len)
3176{
3177 memcpy(to, skb->data, len);
3178}
3179
3180static inline void skb_copy_from_linear_data_offset(const struct sk_buff *skb,
3181 const int offset, void *to,
3182 const unsigned int len)
3183{
3184 memcpy(to, skb->data + offset, len);
3185}
3186
3187static inline void skb_copy_to_linear_data(struct sk_buff *skb,
3188 const void *from,
3189 const unsigned int len)
3190{
3191 memcpy(skb->data, from, len);
3192}
3193
3194static inline void skb_copy_to_linear_data_offset(struct sk_buff *skb,
3195 const int offset,
3196 const void *from,
3197 const unsigned int len)
3198{
3199 memcpy(skb->data + offset, from, len);
3200}
3201
3202void skb_init(void);
3203
3204static inline ktime_t skb_get_ktime(const struct sk_buff *skb)
3205{
3206 return skb->tstamp;
3207}
3208
3209/**
3210 * skb_get_timestamp - get timestamp from a skb
3211 * @skb: skb to get stamp from
3212 * @stamp: pointer to struct timeval to store stamp in
3213 *
3214 * Timestamps are stored in the skb as offsets to a base timestamp.
3215 * This function converts the offset back to a struct timeval and stores
3216 * it in stamp.
3217 */
3218static inline void skb_get_timestamp(const struct sk_buff *skb,
3219 struct timeval *stamp)
3220{
3221 *stamp = ktime_to_timeval(skb->tstamp);
3222}
3223
3224static inline void skb_get_timestampns(const struct sk_buff *skb,
3225 struct timespec *stamp)
3226{
3227 *stamp = ktime_to_timespec(skb->tstamp);
3228}
3229
3230static inline void __net_timestamp(struct sk_buff *skb)
3231{
3232 skb->tstamp = ktime_get_real();
3233}
3234
3235static inline ktime_t net_timedelta(ktime_t t)
3236{
3237 return ktime_sub(ktime_get_real(), t);
3238}
3239
3240static inline ktime_t net_invalid_timestamp(void)
3241{
3242 return 0;
3243}
3244
3245struct sk_buff *skb_clone_sk(struct sk_buff *skb);
3246
3247#ifdef CONFIG_NETWORK_PHY_TIMESTAMPING
3248
3249void skb_clone_tx_timestamp(struct sk_buff *skb);
3250bool skb_defer_rx_timestamp(struct sk_buff *skb);
3251
3252#else /* CONFIG_NETWORK_PHY_TIMESTAMPING */
3253
3254static inline void skb_clone_tx_timestamp(struct sk_buff *skb)
3255{
3256}
3257
3258static inline bool skb_defer_rx_timestamp(struct sk_buff *skb)
3259{
3260 return false;
3261}
3262
3263#endif /* !CONFIG_NETWORK_PHY_TIMESTAMPING */
3264
3265/**
3266 * skb_complete_tx_timestamp() - deliver cloned skb with tx timestamps
3267 *
3268 * PHY drivers may accept clones of transmitted packets for
3269 * timestamping via their phy_driver.txtstamp method. These drivers
3270 * must call this function to return the skb back to the stack with a
3271 * timestamp.
3272 *
3273 * @skb: clone of the the original outgoing packet
3274 * @hwtstamps: hardware time stamps
3275 *
3276 */
3277void skb_complete_tx_timestamp(struct sk_buff *skb,
3278 struct skb_shared_hwtstamps *hwtstamps);
3279
3280void __skb_tstamp_tx(struct sk_buff *orig_skb,
3281 struct skb_shared_hwtstamps *hwtstamps,
3282 struct sock *sk, int tstype);
3283
3284/**
3285 * skb_tstamp_tx - queue clone of skb with send time stamps
3286 * @orig_skb: the original outgoing packet
3287 * @hwtstamps: hardware time stamps, may be NULL if not available
3288 *
3289 * If the skb has a socket associated, then this function clones the
3290 * skb (thus sharing the actual data and optional structures), stores
3291 * the optional hardware time stamping information (if non NULL) or
3292 * generates a software time stamp (otherwise), then queues the clone
3293 * to the error queue of the socket. Errors are silently ignored.
3294 */
3295void skb_tstamp_tx(struct sk_buff *orig_skb,
3296 struct skb_shared_hwtstamps *hwtstamps);
3297
3298static inline void sw_tx_timestamp(struct sk_buff *skb)
3299{
3300 if (skb_shinfo(skb)->tx_flags & SKBTX_SW_TSTAMP &&
3301 !(skb_shinfo(skb)->tx_flags & SKBTX_IN_PROGRESS))
3302 skb_tstamp_tx(skb, NULL);
3303}
3304
3305/**
3306 * skb_tx_timestamp() - Driver hook for transmit timestamping
3307 *
3308 * Ethernet MAC Drivers should call this function in their hard_xmit()
3309 * function immediately before giving the sk_buff to the MAC hardware.
3310 *
3311 * Specifically, one should make absolutely sure that this function is
3312 * called before TX completion of this packet can trigger. Otherwise
3313 * the packet could potentially already be freed.
3314 *
3315 * @skb: A socket buffer.
3316 */
3317static inline void skb_tx_timestamp(struct sk_buff *skb)
3318{
3319 skb_clone_tx_timestamp(skb);
3320 sw_tx_timestamp(skb);
3321}
3322
3323/**
3324 * skb_complete_wifi_ack - deliver skb with wifi status
3325 *
3326 * @skb: the original outgoing packet
3327 * @acked: ack status
3328 *
3329 */
3330void skb_complete_wifi_ack(struct sk_buff *skb, bool acked);
3331
3332__sum16 __skb_checksum_complete_head(struct sk_buff *skb, int len);
3333__sum16 __skb_checksum_complete(struct sk_buff *skb);
3334
3335static inline int skb_csum_unnecessary(const struct sk_buff *skb)
3336{
3337 return ((skb->ip_summed == CHECKSUM_UNNECESSARY) ||
3338 skb->csum_valid ||
3339 (skb->ip_summed == CHECKSUM_PARTIAL &&
3340 skb_checksum_start_offset(skb) >= 0));
3341}
3342
3343/**
3344 * skb_checksum_complete - Calculate checksum of an entire packet
3345 * @skb: packet to process
3346 *
3347 * This function calculates the checksum over the entire packet plus
3348 * the value of skb->csum. The latter can be used to supply the
3349 * checksum of a pseudo header as used by TCP/UDP. It returns the
3350 * checksum.
3351 *
3352 * For protocols that contain complete checksums such as ICMP/TCP/UDP,
3353 * this function can be used to verify that checksum on received
3354 * packets. In that case the function should return zero if the
3355 * checksum is correct. In particular, this function will return zero
3356 * if skb->ip_summed is CHECKSUM_UNNECESSARY which indicates that the
3357 * hardware has already verified the correctness of the checksum.
3358 */
3359static inline __sum16 skb_checksum_complete(struct sk_buff *skb)
3360{
3361 return skb_csum_unnecessary(skb) ?
3362 0 : __skb_checksum_complete(skb);
3363}
3364
3365static inline void __skb_decr_checksum_unnecessary(struct sk_buff *skb)
3366{
3367 if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
3368 if (skb->csum_level == 0)
3369 skb->ip_summed = CHECKSUM_NONE;
3370 else
3371 skb->csum_level--;
3372 }
3373}
3374
3375static inline void __skb_incr_checksum_unnecessary(struct sk_buff *skb)
3376{
3377 if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
3378 if (skb->csum_level < SKB_MAX_CSUM_LEVEL)
3379 skb->csum_level++;
3380 } else if (skb->ip_summed == CHECKSUM_NONE) {
3381 skb->ip_summed = CHECKSUM_UNNECESSARY;
3382 skb->csum_level = 0;
3383 }
3384}
3385
3386static inline void __skb_mark_checksum_bad(struct sk_buff *skb)
3387{
3388 /* Mark current checksum as bad (typically called from GRO
3389 * path). In the case that ip_summed is CHECKSUM_NONE
3390 * this must be the first checksum encountered in the packet.
3391 * When ip_summed is CHECKSUM_UNNECESSARY, this is the first
3392 * checksum after the last one validated. For UDP, a zero
3393 * checksum can not be marked as bad.
3394 */
3395
3396 if (skb->ip_summed == CHECKSUM_NONE ||
3397 skb->ip_summed == CHECKSUM_UNNECESSARY)
3398 skb->csum_bad = 1;
3399}
3400
3401/* Check if we need to perform checksum complete validation.
3402 *
3403 * Returns true if checksum complete is needed, false otherwise
3404 * (either checksum is unnecessary or zero checksum is allowed).
3405 */
3406static inline bool __skb_checksum_validate_needed(struct sk_buff *skb,
3407 bool zero_okay,
3408 __sum16 check)
3409{
3410 if (skb_csum_unnecessary(skb) || (zero_okay && !check)) {
3411 skb->csum_valid = 1;
3412 __skb_decr_checksum_unnecessary(skb);
3413 return false;
3414 }
3415
3416 return true;
3417}
3418
3419/* For small packets <= CHECKSUM_BREAK peform checksum complete directly
3420 * in checksum_init.
3421 */
3422#define CHECKSUM_BREAK 76
3423
3424/* Unset checksum-complete
3425 *
3426 * Unset checksum complete can be done when packet is being modified
3427 * (uncompressed for instance) and checksum-complete value is
3428 * invalidated.
3429 */
3430static inline void skb_checksum_complete_unset(struct sk_buff *skb)
3431{
3432 if (skb->ip_summed == CHECKSUM_COMPLETE)
3433 skb->ip_summed = CHECKSUM_NONE;
3434}
3435
3436/* Validate (init) checksum based on checksum complete.
3437 *
3438 * Return values:
3439 * 0: checksum is validated or try to in skb_checksum_complete. In the latter
3440 * case the ip_summed will not be CHECKSUM_UNNECESSARY and the pseudo
3441 * checksum is stored in skb->csum for use in __skb_checksum_complete
3442 * non-zero: value of invalid checksum
3443 *
3444 */
3445static inline __sum16 __skb_checksum_validate_complete(struct sk_buff *skb,
3446 bool complete,
3447 __wsum psum)
3448{
3449 if (skb->ip_summed == CHECKSUM_COMPLETE) {
3450 if (!csum_fold(csum_add(psum, skb->csum))) {
3451 skb->csum_valid = 1;
3452 return 0;
3453 }
3454 } else if (skb->csum_bad) {
3455 /* ip_summed == CHECKSUM_NONE in this case */
3456 return (__force __sum16)1;
3457 }
3458
3459 skb->csum = psum;
3460
3461 if (complete || skb->len <= CHECKSUM_BREAK) {
3462 __sum16 csum;
3463
3464 csum = __skb_checksum_complete(skb);
3465 skb->csum_valid = !csum;
3466 return csum;
3467 }
3468
3469 return 0;
3470}
3471
3472static inline __wsum null_compute_pseudo(struct sk_buff *skb, int proto)
3473{
3474 return 0;
3475}
3476
3477/* Perform checksum validate (init). Note that this is a macro since we only
3478 * want to calculate the pseudo header which is an input function if necessary.
3479 * First we try to validate without any computation (checksum unnecessary) and
3480 * then calculate based on checksum complete calling the function to compute
3481 * pseudo header.
3482 *
3483 * Return values:
3484 * 0: checksum is validated or try to in skb_checksum_complete
3485 * non-zero: value of invalid checksum
3486 */
3487#define __skb_checksum_validate(skb, proto, complete, \
3488 zero_okay, check, compute_pseudo) \
3489({ \
3490 __sum16 __ret = 0; \
3491 skb->csum_valid = 0; \
3492 if (__skb_checksum_validate_needed(skb, zero_okay, check)) \
3493 __ret = __skb_checksum_validate_complete(skb, \
3494 complete, compute_pseudo(skb, proto)); \
3495 __ret; \
3496})
3497
3498#define skb_checksum_init(skb, proto, compute_pseudo) \
3499 __skb_checksum_validate(skb, proto, false, false, 0, compute_pseudo)
3500
3501#define skb_checksum_init_zero_check(skb, proto, check, compute_pseudo) \
3502 __skb_checksum_validate(skb, proto, false, true, check, compute_pseudo)
3503
3504#define skb_checksum_validate(skb, proto, compute_pseudo) \
3505 __skb_checksum_validate(skb, proto, true, false, 0, compute_pseudo)
3506
3507#define skb_checksum_validate_zero_check(skb, proto, check, \
3508 compute_pseudo) \
3509 __skb_checksum_validate(skb, proto, true, true, check, compute_pseudo)
3510
3511#define skb_checksum_simple_validate(skb) \
3512 __skb_checksum_validate(skb, 0, true, false, 0, null_compute_pseudo)
3513
3514static inline bool __skb_checksum_convert_check(struct sk_buff *skb)
3515{
3516 return (skb->ip_summed == CHECKSUM_NONE &&
3517 skb->csum_valid && !skb->csum_bad);
3518}
3519
3520static inline void __skb_checksum_convert(struct sk_buff *skb,
3521 __sum16 check, __wsum pseudo)
3522{
3523 skb->csum = ~pseudo;
3524 skb->ip_summed = CHECKSUM_COMPLETE;
3525}
3526
3527#define skb_checksum_try_convert(skb, proto, check, compute_pseudo) \
3528do { \
3529 if (__skb_checksum_convert_check(skb)) \
3530 __skb_checksum_convert(skb, check, \
3531 compute_pseudo(skb, proto)); \
3532} while (0)
3533
3534static inline void skb_remcsum_adjust_partial(struct sk_buff *skb, void *ptr,
3535 u16 start, u16 offset)
3536{
3537 skb->ip_summed = CHECKSUM_PARTIAL;
3538 skb->csum_start = ((unsigned char *)ptr + start) - skb->head;
3539 skb->csum_offset = offset - start;
3540}
3541
3542/* Update skbuf and packet to reflect the remote checksum offload operation.
3543 * When called, ptr indicates the starting point for skb->csum when
3544 * ip_summed is CHECKSUM_COMPLETE. If we need create checksum complete
3545 * here, skb_postpull_rcsum is done so skb->csum start is ptr.
3546 */
3547static inline void skb_remcsum_process(struct sk_buff *skb, void *ptr,
3548 int start, int offset, bool nopartial)
3549{
3550 __wsum delta;
3551
3552 if (!nopartial) {
3553 skb_remcsum_adjust_partial(skb, ptr, start, offset);
3554 return;
3555 }
3556
3557 if (unlikely(skb->ip_summed != CHECKSUM_COMPLETE)) {
3558 __skb_checksum_complete(skb);
3559 skb_postpull_rcsum(skb, skb->data, ptr - (void *)skb->data);
3560 }
3561
3562 delta = remcsum_adjust(ptr, skb->csum, start, offset);
3563
3564 /* Adjust skb->csum since we changed the packet */
3565 skb->csum = csum_add(skb->csum, delta);
3566}
3567
3568static inline struct nf_conntrack *skb_nfct(const struct sk_buff *skb)
3569{
3570#if IS_ENABLED(CONFIG_NF_CONNTRACK)
3571 return (void *)(skb->_nfct & SKB_NFCT_PTRMASK);
3572#else
3573 return NULL;
3574#endif
3575}
3576
3577#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
3578void nf_conntrack_destroy(struct nf_conntrack *nfct);
3579static inline void nf_conntrack_put(struct nf_conntrack *nfct)
3580{
3581 if (nfct && atomic_dec_and_test(&nfct->use))
3582 nf_conntrack_destroy(nfct);
3583}
3584static inline void nf_conntrack_get(struct nf_conntrack *nfct)
3585{
3586 if (nfct)
3587 atomic_inc(&nfct->use);
3588}
3589#endif
3590#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
3591static inline void nf_bridge_put(struct nf_bridge_info *nf_bridge)
3592{
3593 if (nf_bridge && atomic_dec_and_test(&nf_bridge->use))
3594 kfree(nf_bridge);
3595}
3596static inline void nf_bridge_get(struct nf_bridge_info *nf_bridge)
3597{
3598 if (nf_bridge)
3599 atomic_inc(&nf_bridge->use);
3600}
3601#endif /* CONFIG_BRIDGE_NETFILTER */
3602static inline void nf_reset(struct sk_buff *skb)
3603{
3604#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
3605 nf_conntrack_put(skb_nfct(skb));
3606 skb->_nfct = 0;
3607#endif
3608#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
3609 nf_bridge_put(skb->nf_bridge);
3610 skb->nf_bridge = NULL;
3611#endif
3612}
3613
3614static inline void nf_reset_trace(struct sk_buff *skb)
3615{
3616#if IS_ENABLED(CONFIG_NETFILTER_XT_TARGET_TRACE) || defined(CONFIG_NF_TABLES)
3617 skb->nf_trace = 0;
3618#endif
3619}
3620
3621/* Note: This doesn't put any conntrack and bridge info in dst. */
3622static inline void __nf_copy(struct sk_buff *dst, const struct sk_buff *src,
3623 bool copy)
3624{
3625#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
3626 dst->_nfct = src->_nfct;
3627 nf_conntrack_get(skb_nfct(src));
3628#endif
3629#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
3630 dst->nf_bridge = src->nf_bridge;
3631 nf_bridge_get(src->nf_bridge);
3632#endif
3633#if IS_ENABLED(CONFIG_NETFILTER_XT_TARGET_TRACE) || defined(CONFIG_NF_TABLES)
3634 if (copy)
3635 dst->nf_trace = src->nf_trace;
3636#endif
3637}
3638
3639static inline void nf_copy(struct sk_buff *dst, const struct sk_buff *src)
3640{
3641#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
3642 nf_conntrack_put(skb_nfct(dst));
3643#endif
3644#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
3645 nf_bridge_put(dst->nf_bridge);
3646#endif
3647 __nf_copy(dst, src, true);
3648}
3649
3650#ifdef CONFIG_NETWORK_SECMARK
3651static inline void skb_copy_secmark(struct sk_buff *to, const struct sk_buff *from)
3652{
3653 to->secmark = from->secmark;
3654}
3655
3656static inline void skb_init_secmark(struct sk_buff *skb)
3657{
3658 skb->secmark = 0;
3659}
3660#else
3661static inline void skb_copy_secmark(struct sk_buff *to, const struct sk_buff *from)
3662{ }
3663
3664static inline void skb_init_secmark(struct sk_buff *skb)
3665{ }
3666#endif
3667
3668static inline bool skb_irq_freeable(const struct sk_buff *skb)
3669{
3670 return !skb->destructor &&
3671#if IS_ENABLED(CONFIG_XFRM)
3672 !skb->sp &&
3673#endif
3674 !skb_nfct(skb) &&
3675 !skb->_skb_refdst &&
3676 !skb_has_frag_list(skb);
3677}
3678
3679static inline void skb_set_queue_mapping(struct sk_buff *skb, u16 queue_mapping)
3680{
3681 skb->queue_mapping = queue_mapping;
3682}
3683
3684static inline u16 skb_get_queue_mapping(const struct sk_buff *skb)
3685{
3686 return skb->queue_mapping;
3687}
3688
3689static inline void skb_copy_queue_mapping(struct sk_buff *to, const struct sk_buff *from)
3690{
3691 to->queue_mapping = from->queue_mapping;
3692}
3693
3694static inline void skb_record_rx_queue(struct sk_buff *skb, u16 rx_queue)
3695{
3696 skb->queue_mapping = rx_queue + 1;
3697}
3698
3699static inline u16 skb_get_rx_queue(const struct sk_buff *skb)
3700{
3701 return skb->queue_mapping - 1;
3702}
3703
3704static inline bool skb_rx_queue_recorded(const struct sk_buff *skb)
3705{
3706 return skb->queue_mapping != 0;
3707}
3708
3709static inline void skb_set_dst_pending_confirm(struct sk_buff *skb, u32 val)
3710{
3711 skb->dst_pending_confirm = val;
3712}
3713
3714static inline bool skb_get_dst_pending_confirm(const struct sk_buff *skb)
3715{
3716 return skb->dst_pending_confirm != 0;
3717}
3718
3719static inline struct sec_path *skb_sec_path(struct sk_buff *skb)
3720{
3721#ifdef CONFIG_XFRM
3722 return skb->sp;
3723#else
3724 return NULL;
3725#endif
3726}
3727
3728/* Keeps track of mac header offset relative to skb->head.
3729 * It is useful for TSO of Tunneling protocol. e.g. GRE.
3730 * For non-tunnel skb it points to skb_mac_header() and for
3731 * tunnel skb it points to outer mac header.
3732 * Keeps track of level of encapsulation of network headers.
3733 */
3734struct skb_gso_cb {
3735 union {
3736 int mac_offset;
3737 int data_offset;
3738 };
3739 int encap_level;
3740 __wsum csum;
3741 __u16 csum_start;
3742};
3743#define SKB_SGO_CB_OFFSET 32
3744#define SKB_GSO_CB(skb) ((struct skb_gso_cb *)((skb)->cb + SKB_SGO_CB_OFFSET))
3745
3746static inline int skb_tnl_header_len(const struct sk_buff *inner_skb)
3747{
3748 return (skb_mac_header(inner_skb) - inner_skb->head) -
3749 SKB_GSO_CB(inner_skb)->mac_offset;
3750}
3751
3752static inline int gso_pskb_expand_head(struct sk_buff *skb, int extra)
3753{
3754 int new_headroom, headroom;
3755 int ret;
3756
3757 headroom = skb_headroom(skb);
3758 ret = pskb_expand_head(skb, extra, 0, GFP_ATOMIC);
3759 if (ret)
3760 return ret;
3761
3762 new_headroom = skb_headroom(skb);
3763 SKB_GSO_CB(skb)->mac_offset += (new_headroom - headroom);
3764 return 0;
3765}
3766
3767static inline void gso_reset_checksum(struct sk_buff *skb, __wsum res)
3768{
3769 /* Do not update partial checksums if remote checksum is enabled. */
3770 if (skb->remcsum_offload)
3771 return;
3772
3773 SKB_GSO_CB(skb)->csum = res;
3774 SKB_GSO_CB(skb)->csum_start = skb_checksum_start(skb) - skb->head;
3775}
3776
3777/* Compute the checksum for a gso segment. First compute the checksum value
3778 * from the start of transport header to SKB_GSO_CB(skb)->csum_start, and
3779 * then add in skb->csum (checksum from csum_start to end of packet).
3780 * skb->csum and csum_start are then updated to reflect the checksum of the
3781 * resultant packet starting from the transport header-- the resultant checksum
3782 * is in the res argument (i.e. normally zero or ~ of checksum of a pseudo
3783 * header.
3784 */
3785static inline __sum16 gso_make_checksum(struct sk_buff *skb, __wsum res)
3786{
3787 unsigned char *csum_start = skb_transport_header(skb);
3788 int plen = (skb->head + SKB_GSO_CB(skb)->csum_start) - csum_start;
3789 __wsum partial = SKB_GSO_CB(skb)->csum;
3790
3791 SKB_GSO_CB(skb)->csum = res;
3792 SKB_GSO_CB(skb)->csum_start = csum_start - skb->head;
3793
3794 return csum_fold(csum_partial(csum_start, plen, partial));
3795}
3796
3797static inline bool skb_is_gso(const struct sk_buff *skb)
3798{
3799 return skb_shinfo(skb)->gso_size;
3800}
3801
3802/* Note: Should be called only if skb_is_gso(skb) is true */
3803static inline bool skb_is_gso_v6(const struct sk_buff *skb)
3804{
3805 return skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6;
3806}
3807
3808static inline void skb_gso_reset(struct sk_buff *skb)
3809{
3810 skb_shinfo(skb)->gso_size = 0;
3811 skb_shinfo(skb)->gso_segs = 0;
3812 skb_shinfo(skb)->gso_type = 0;
3813}
3814
3815void __skb_warn_lro_forwarding(const struct sk_buff *skb);
3816
3817static inline bool skb_warn_if_lro(const struct sk_buff *skb)
3818{
3819 /* LRO sets gso_size but not gso_type, whereas if GSO is really
3820 * wanted then gso_type will be set. */
3821 const struct skb_shared_info *shinfo = skb_shinfo(skb);
3822
3823 if (skb_is_nonlinear(skb) && shinfo->gso_size != 0 &&
3824 unlikely(shinfo->gso_type == 0)) {
3825 __skb_warn_lro_forwarding(skb);
3826 return true;
3827 }
3828 return false;
3829}
3830
3831static inline void skb_forward_csum(struct sk_buff *skb)
3832{
3833 /* Unfortunately we don't support this one. Any brave souls? */
3834 if (skb->ip_summed == CHECKSUM_COMPLETE)
3835 skb->ip_summed = CHECKSUM_NONE;
3836}
3837
3838/**
3839 * skb_checksum_none_assert - make sure skb ip_summed is CHECKSUM_NONE
3840 * @skb: skb to check
3841 *
3842 * fresh skbs have their ip_summed set to CHECKSUM_NONE.
3843 * Instead of forcing ip_summed to CHECKSUM_NONE, we can
3844 * use this helper, to document places where we make this assertion.
3845 */
3846static inline void skb_checksum_none_assert(const struct sk_buff *skb)
3847{
3848#ifdef DEBUG
3849 BUG_ON(skb->ip_summed != CHECKSUM_NONE);
3850#endif
3851}
3852
3853bool skb_partial_csum_set(struct sk_buff *skb, u16 start, u16 off);
3854
3855int skb_checksum_setup(struct sk_buff *skb, bool recalculate);
3856struct sk_buff *skb_checksum_trimmed(struct sk_buff *skb,
3857 unsigned int transport_len,
3858 __sum16(*skb_chkf)(struct sk_buff *skb));
3859
3860/**
3861 * skb_head_is_locked - Determine if the skb->head is locked down
3862 * @skb: skb to check
3863 *
3864 * The head on skbs build around a head frag can be removed if they are
3865 * not cloned. This function returns true if the skb head is locked down
3866 * due to either being allocated via kmalloc, or by being a clone with
3867 * multiple references to the head.
3868 */
3869static inline bool skb_head_is_locked(const struct sk_buff *skb)
3870{
3871 return !skb->head_frag || skb_cloned(skb);
3872}
3873
3874/**
3875 * skb_gso_network_seglen - Return length of individual segments of a gso packet
3876 *
3877 * @skb: GSO skb
3878 *
3879 * skb_gso_network_seglen is used to determine the real size of the
3880 * individual segments, including Layer3 (IP, IPv6) and L4 headers (TCP/UDP).
3881 *
3882 * The MAC/L2 header is not accounted for.
3883 */
3884static inline unsigned int skb_gso_network_seglen(const struct sk_buff *skb)
3885{
3886 unsigned int hdr_len = skb_transport_header(skb) -
3887 skb_network_header(skb);
3888 return hdr_len + skb_gso_transport_seglen(skb);
3889}
3890
3891/* Local Checksum Offload.
3892 * Compute outer checksum based on the assumption that the
3893 * inner checksum will be offloaded later.
3894 * See Documentation/networking/checksum-offloads.txt for
3895 * explanation of how this works.
3896 * Fill in outer checksum adjustment (e.g. with sum of outer
3897 * pseudo-header) before calling.
3898 * Also ensure that inner checksum is in linear data area.
3899 */
3900static inline __wsum lco_csum(struct sk_buff *skb)
3901{
3902 unsigned char *csum_start = skb_checksum_start(skb);
3903 unsigned char *l4_hdr = skb_transport_header(skb);
3904 __wsum partial;
3905
3906 /* Start with complement of inner checksum adjustment */
3907 partial = ~csum_unfold(*(__force __sum16 *)(csum_start +
3908 skb->csum_offset));
3909
3910 /* Add in checksum of our headers (incl. outer checksum
3911 * adjustment filled in by caller) and return result.
3912 */
3913 return csum_partial(l4_hdr, csum_start - l4_hdr, partial);
3914}
3915
3916#endif /* __KERNEL__ */
3917#endif /* _LINUX_SKBUFF_H */
3918