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