1 /* SPDX-License-Identifier: GPL-2.0-or-later */ 2 /* 3 * Definitions for the 'struct sk_buff' memory handlers. 4 * 5 * Authors: 6 * Alan Cox, <gw4pts@gw4pts.ampr.org> 7 * Florian La Roche, <rzsfl@rz.uni-sb.de> 8 */ 9 10 #ifndef _LINUX_SKBUFF_H 11 #define _LINUX_SKBUFF_H 12 13 #include <linux/kernel.h> 14 #include <linux/compiler.h> 15 #include <linux/time.h> 16 #include <linux/bug.h> 17 #include <linux/bvec.h> 18 #include <linux/cache.h> 19 #include <linux/rbtree.h> 20 #include <linux/socket.h> 21 #include <linux/refcount.h> 22 23 #include <linux/atomic.h> 24 #include <asm/types.h> 25 #include <linux/spinlock.h> 26 #include <linux/net.h> 27 #include <linux/textsearch.h> 28 #include <net/checksum.h> 29 #include <linux/rcupdate.h> 30 #include <linux/hrtimer.h> 31 #include <linux/dma-mapping.h> 32 #include <linux/netdev_features.h> 33 #include <linux/sched.h> 34 #include <linux/sched/clock.h> 35 #include <net/flow_dissector.h> 36 #include <linux/splice.h> 37 #include <linux/in6.h> 38 #include <linux/if_packet.h> 39 #include <net/flow.h> 40 #if IS_ENABLED(CONFIG_NF_CONNTRACK) 41 #include <linux/netfilter/nf_conntrack_common.h> 42 #endif 43 44 /* The interface for checksum offload between the stack and networking drivers 45 * is as follows... 46 * 47 * A. IP checksum related features 48 * 49 * Drivers advertise checksum offload capabilities in the features of a device. 50 * From the stack's point of view these are capabilities offered by the driver, 51 * a driver typically only advertises features that it is capable of offloading 52 * to its device. 53 * 54 * The checksum related features are: 55 * 56 * NETIF_F_HW_CSUM - The driver (or its device) is able to compute one 57 * IP (one's complement) checksum for any combination 58 * of protocols or protocol layering. The checksum is 59 * computed and set in a packet per the CHECKSUM_PARTIAL 60 * interface (see below). 61 * 62 * NETIF_F_IP_CSUM - Driver (device) is only able to checksum plain 63 * TCP or UDP packets over IPv4. These are specifically 64 * unencapsulated packets of the form IPv4|TCP or 65 * IPv4|UDP where the Protocol field in the IPv4 header 66 * is TCP or UDP. The IPv4 header may contain IP options 67 * This feature cannot be set in features for a device 68 * with NETIF_F_HW_CSUM also set. This feature is being 69 * DEPRECATED (see below). 70 * 71 * NETIF_F_IPV6_CSUM - Driver (device) is only able to checksum plain 72 * TCP or UDP packets over IPv6. These are specifically 73 * unencapsulated packets of the form IPv6|TCP or 74 * IPv4|UDP where the Next Header field in the IPv6 75 * header is either TCP or UDP. IPv6 extension headers 76 * are not supported with this feature. This feature 77 * cannot be set in features for a device with 78 * NETIF_F_HW_CSUM also set. This feature is being 79 * DEPRECATED (see below). 80 * 81 * NETIF_F_RXCSUM - Driver (device) performs receive checksum offload. 82 * This flag is used only used to disable the RX checksum 83 * feature for a device. The stack will accept receive 84 * checksum indication in packets received on a device 85 * regardless of whether NETIF_F_RXCSUM is set. 86 * 87 * B. Checksumming of received packets by device. Indication of checksum 88 * verification is in set skb->ip_summed. Possible values are: 89 * 90 * CHECKSUM_NONE: 91 * 92 * Device did not checksum this packet e.g. due to lack of capabilities. 93 * The packet contains full (though not verified) checksum in packet but 94 * not in skb->csum. Thus, skb->csum is undefined in this case. 95 * 96 * CHECKSUM_UNNECESSARY: 97 * 98 * The hardware you're dealing with doesn't calculate the full checksum 99 * (as in CHECKSUM_COMPLETE), but it does parse headers and verify checksums 100 * for specific protocols. For such packets it will set CHECKSUM_UNNECESSARY 101 * if their checksums are okay. skb->csum is still undefined in this case 102 * though. A driver or device must never modify the checksum field in the 103 * packet even if checksum is verified. 104 * 105 * CHECKSUM_UNNECESSARY is applicable to following protocols: 106 * TCP: IPv6 and IPv4. 107 * UDP: IPv4 and IPv6. A device may apply CHECKSUM_UNNECESSARY to a 108 * zero UDP checksum for either IPv4 or IPv6, the networking stack 109 * may perform further validation in this case. 110 * GRE: only if the checksum is present in the header. 111 * SCTP: indicates the CRC in SCTP header has been validated. 112 * FCOE: indicates the CRC in FC frame has been validated. 113 * 114 * skb->csum_level indicates the number of consecutive checksums found in 115 * the packet minus one that have been verified as CHECKSUM_UNNECESSARY. 116 * For instance if a device receives an IPv6->UDP->GRE->IPv4->TCP packet 117 * and a device is able to verify the checksums for UDP (possibly zero), 118 * GRE (checksum flag is set), and TCP-- skb->csum_level would be set to 119 * two. If the device were only able to verify the UDP checksum and not 120 * GRE, either because it doesn't support GRE checksum of because GRE 121 * checksum is bad, skb->csum_level would be set to zero (TCP checksum is 122 * not considered in this case). 123 * 124 * CHECKSUM_COMPLETE: 125 * 126 * This is the most generic way. The device supplied checksum of the _whole_ 127 * packet as seen by netif_rx() and fills out in skb->csum. Meaning, the 128 * hardware doesn't need to parse L3/L4 headers to implement this. 129 * 130 * Notes: 131 * - Even if device supports only some protocols, but is able to produce 132 * skb->csum, it MUST use CHECKSUM_COMPLETE, not CHECKSUM_UNNECESSARY. 133 * - CHECKSUM_COMPLETE is not applicable to SCTP and FCoE protocols. 134 * 135 * CHECKSUM_PARTIAL: 136 * 137 * A checksum is set up to be offloaded to a device as described in the 138 * output description for CHECKSUM_PARTIAL. This may occur on a packet 139 * received directly from another Linux OS, e.g., a virtualized Linux kernel 140 * on the same host, or it may be set in the input path in GRO or remote 141 * checksum offload. For the purposes of checksum verification, the checksum 142 * referred to by skb->csum_start + skb->csum_offset and any preceding 143 * checksums in the packet are considered verified. Any checksums in the 144 * packet that are after the checksum being offloaded are not considered to 145 * be verified. 146 * 147 * C. Checksumming on transmit for non-GSO. The stack requests checksum offload 148 * in the skb->ip_summed for a packet. Values are: 149 * 150 * CHECKSUM_PARTIAL: 151 * 152 * The driver is required to checksum the packet as seen by hard_start_xmit() 153 * from skb->csum_start up to the end, and to record/write the checksum at 154 * offset skb->csum_start + skb->csum_offset. A driver may verify that the 155 * csum_start and csum_offset values are valid values given the length and 156 * offset of the packet, however they should not attempt to validate that the 157 * checksum refers to a legitimate transport layer checksum-- it is the 158 * purview of the stack to validate that csum_start and csum_offset are set 159 * correctly. 160 * 161 * When the stack requests checksum offload for a packet, the driver MUST 162 * ensure that the checksum is set correctly. A driver can either offload the 163 * checksum calculation to the device, or call skb_checksum_help (in the case 164 * that the device does not support offload for a particular checksum). 165 * 166 * NETIF_F_IP_CSUM and NETIF_F_IPV6_CSUM are being deprecated in favor of 167 * NETIF_F_HW_CSUM. New devices should use NETIF_F_HW_CSUM to indicate 168 * checksum offload capability. 169 * skb_csum_hwoffload_help() can be called to resolve CHECKSUM_PARTIAL based 170 * on network device checksumming capabilities: if a packet does not match 171 * them, skb_checksum_help or skb_crc32c_help (depending on the value of 172 * csum_not_inet, see item D.) is called to resolve the checksum. 173 * 174 * CHECKSUM_NONE: 175 * 176 * The skb was already checksummed by the protocol, or a checksum is not 177 * required. 178 * 179 * CHECKSUM_UNNECESSARY: 180 * 181 * This has the same meaning on as CHECKSUM_NONE for checksum offload on 182 * output. 183 * 184 * CHECKSUM_COMPLETE: 185 * Not used in checksum output. If a driver observes a packet with this value 186 * set in skbuff, if should treat as CHECKSUM_NONE being set. 187 * 188 * D. Non-IP checksum (CRC) offloads 189 * 190 * NETIF_F_SCTP_CRC - This feature indicates that a device is capable of 191 * offloading the SCTP CRC in a packet. To perform this offload the stack 192 * will set set csum_start and csum_offset accordingly, set ip_summed to 193 * CHECKSUM_PARTIAL and set csum_not_inet to 1, to provide an indication in 194 * the skbuff that the CHECKSUM_PARTIAL refers to CRC32c. 195 * A driver that supports both IP checksum offload and SCTP CRC32c offload 196 * must verify which offload is configured for a packet by testing the 197 * value of skb->csum_not_inet; skb_crc32c_csum_help is provided to resolve 198 * CHECKSUM_PARTIAL on skbs where csum_not_inet is set to 1. 199 * 200 * NETIF_F_FCOE_CRC - This feature indicates that a device is capable of 201 * offloading the FCOE CRC in a packet. To perform this offload the stack 202 * will set ip_summed to CHECKSUM_PARTIAL and set csum_start and csum_offset 203 * accordingly. Note the there is no indication in the skbuff that the 204 * CHECKSUM_PARTIAL refers to an FCOE checksum, a driver that supports 205 * both IP checksum offload and FCOE CRC offload must verify which offload 206 * is configured for a packet presumably by inspecting packet headers. 207 * 208 * E. Checksumming on output with GSO. 209 * 210 * In the case of a GSO packet (skb_is_gso(skb) is true), checksum offload 211 * is implied by the SKB_GSO_* flags in gso_type. Most obviously, if the 212 * gso_type is SKB_GSO_TCPV4 or SKB_GSO_TCPV6, TCP checksum offload as 213 * part of the GSO operation is implied. If a checksum is being offloaded 214 * with GSO then ip_summed is CHECKSUM_PARTIAL, csum_start and csum_offset 215 * are set to refer to the outermost checksum being offload (two offloaded 216 * checksums are possible with UDP encapsulation). 217 */ 218 219 /* Don't change this without changing skb_csum_unnecessary! */ 220 #define CHECKSUM_NONE 0 221 #define CHECKSUM_UNNECESSARY 1 222 #define CHECKSUM_COMPLETE 2 223 #define CHECKSUM_PARTIAL 3 224 225 /* Maximum value in skb->csum_level */ 226 #define SKB_MAX_CSUM_LEVEL 3 227 228 #define SKB_DATA_ALIGN(X) ALIGN(X, SMP_CACHE_BYTES) 229 #define SKB_WITH_OVERHEAD(X) \ 230 ((X) - SKB_DATA_ALIGN(sizeof(struct skb_shared_info))) 231 #define SKB_MAX_ORDER(X, ORDER) \ 232 SKB_WITH_OVERHEAD((PAGE_SIZE << (ORDER)) - (X)) 233 #define SKB_MAX_HEAD(X) (SKB_MAX_ORDER((X), 0)) 234 #define SKB_MAX_ALLOC (SKB_MAX_ORDER(0, 2)) 235 236 /* return minimum truesize of one skb containing X bytes of data */ 237 #define SKB_TRUESIZE(X) ((X) + \ 238 SKB_DATA_ALIGN(sizeof(struct sk_buff)) + \ 239 SKB_DATA_ALIGN(sizeof(struct skb_shared_info))) 240 241 struct net_device; 242 struct scatterlist; 243 struct pipe_inode_info; 244 struct iov_iter; 245 struct napi_struct; 246 struct bpf_prog; 247 union bpf_attr; 248 struct skb_ext; 249 250 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER) 251 struct nf_bridge_info { 252 enum { 253 BRNF_PROTO_UNCHANGED, 254 BRNF_PROTO_8021Q, 255 BRNF_PROTO_PPPOE 256 } orig_proto:8; 257 u8 pkt_otherhost:1; 258 u8 in_prerouting:1; 259 u8 bridged_dnat:1; 260 __u16 frag_max_size; 261 struct net_device *physindev; 262 263 /* always valid & non-NULL from FORWARD on, for physdev match */ 264 struct net_device *physoutdev; 265 union { 266 /* prerouting: detect dnat in orig/reply direction */ 267 __be32 ipv4_daddr; 268 struct in6_addr ipv6_daddr; 269 270 /* after prerouting + nat detected: store original source 271 * mac since neigh resolution overwrites it, only used while 272 * skb is out in neigh layer. 273 */ 274 char neigh_header[8]; 275 }; 276 }; 277 #endif 278 279 #if IS_ENABLED(CONFIG_NET_TC_SKB_EXT) 280 /* Chain in tc_skb_ext will be used to share the tc chain with 281 * ovs recirc_id. It will be set to the current chain by tc 282 * and read by ovs to recirc_id. 283 */ 284 struct tc_skb_ext { 285 __u32 chain; 286 }; 287 #endif 288 289 struct sk_buff_head { 290 /* These two members must be first. */ 291 struct sk_buff *next; 292 struct sk_buff *prev; 293 294 __u32 qlen; 295 spinlock_t lock; 296 }; 297 298 struct sk_buff; 299 300 /* To allow 64K frame to be packed as single skb without frag_list we 301 * require 64K/PAGE_SIZE pages plus 1 additional page to allow for 302 * buffers which do not start on a page boundary. 303 * 304 * Since GRO uses frags we allocate at least 16 regardless of page 305 * size. 306 */ 307 #if (65536/PAGE_SIZE + 1) < 16 308 #define MAX_SKB_FRAGS 16UL 309 #else 310 #define MAX_SKB_FRAGS (65536/PAGE_SIZE + 1) 311 #endif 312 extern int sysctl_max_skb_frags; 313 314 /* Set skb_shinfo(skb)->gso_size to this in case you want skb_segment to 315 * segment using its current segmentation instead. 316 */ 317 #define GSO_BY_FRAGS 0xFFFF 318 319 typedef struct bio_vec skb_frag_t; 320 321 /** 322 * skb_frag_size() - Returns the size of a skb fragment 323 * @frag: skb fragment 324 */ 325 static inline unsigned int skb_frag_size(const skb_frag_t *frag) 326 { 327 return frag->bv_len; 328 } 329 330 /** 331 * skb_frag_size_set() - Sets the size of a skb fragment 332 * @frag: skb fragment 333 * @size: size of fragment 334 */ 335 static inline void skb_frag_size_set(skb_frag_t *frag, unsigned int size) 336 { 337 frag->bv_len = size; 338 } 339 340 /** 341 * skb_frag_size_add() - Increments the size of a skb fragment by @delta 342 * @frag: skb fragment 343 * @delta: value to add 344 */ 345 static inline void skb_frag_size_add(skb_frag_t *frag, int delta) 346 { 347 frag->bv_len += delta; 348 } 349 350 /** 351 * skb_frag_size_sub() - Decrements the size of a skb fragment by @delta 352 * @frag: skb fragment 353 * @delta: value to subtract 354 */ 355 static inline void skb_frag_size_sub(skb_frag_t *frag, int delta) 356 { 357 frag->bv_len -= delta; 358 } 359 360 /** 361 * skb_frag_must_loop - Test if %p is a high memory page 362 * @p: fragment's page 363 */ 364 static inline bool skb_frag_must_loop(struct page *p) 365 { 366 #if defined(CONFIG_HIGHMEM) 367 if (PageHighMem(p)) 368 return true; 369 #endif 370 return false; 371 } 372 373 /** 374 * skb_frag_foreach_page - loop over pages in a fragment 375 * 376 * @f: skb frag to operate on 377 * @f_off: offset from start of f->bv_page 378 * @f_len: length from f_off to loop over 379 * @p: (temp var) current page 380 * @p_off: (temp var) offset from start of current page, 381 * non-zero only on first page. 382 * @p_len: (temp var) length in current page, 383 * < PAGE_SIZE only on first and last page. 384 * @copied: (temp var) length so far, excluding current p_len. 385 * 386 * A fragment can hold a compound page, in which case per-page 387 * operations, notably kmap_atomic, must be called for each 388 * regular page. 389 */ 390 #define skb_frag_foreach_page(f, f_off, f_len, p, p_off, p_len, copied) \ 391 for (p = skb_frag_page(f) + ((f_off) >> PAGE_SHIFT), \ 392 p_off = (f_off) & (PAGE_SIZE - 1), \ 393 p_len = skb_frag_must_loop(p) ? \ 394 min_t(u32, f_len, PAGE_SIZE - p_off) : f_len, \ 395 copied = 0; \ 396 copied < f_len; \ 397 copied += p_len, p++, p_off = 0, \ 398 p_len = min_t(u32, f_len - copied, PAGE_SIZE)) \ 399 400 #define HAVE_HW_TIME_STAMP 401 402 /** 403 * struct skb_shared_hwtstamps - hardware time stamps 404 * @hwtstamp: hardware time stamp transformed into duration 405 * since arbitrary point in time 406 * 407 * Software time stamps generated by ktime_get_real() are stored in 408 * skb->tstamp. 409 * 410 * hwtstamps can only be compared against other hwtstamps from 411 * the same device. 412 * 413 * This structure is attached to packets as part of the 414 * &skb_shared_info. Use skb_hwtstamps() to get a pointer. 415 */ 416 struct skb_shared_hwtstamps { 417 ktime_t hwtstamp; 418 }; 419 420 /* Definitions for tx_flags in struct skb_shared_info */ 421 enum { 422 /* generate hardware time stamp */ 423 SKBTX_HW_TSTAMP = 1 << 0, 424 425 /* generate software time stamp when queueing packet to NIC */ 426 SKBTX_SW_TSTAMP = 1 << 1, 427 428 /* device driver is going to provide hardware time stamp */ 429 SKBTX_IN_PROGRESS = 1 << 2, 430 431 /* device driver supports TX zero-copy buffers */ 432 SKBTX_DEV_ZEROCOPY = 1 << 3, 433 434 /* generate wifi status information (where possible) */ 435 SKBTX_WIFI_STATUS = 1 << 4, 436 437 /* This indicates at least one fragment might be overwritten 438 * (as in vmsplice(), sendfile() ...) 439 * If we need to compute a TX checksum, we'll need to copy 440 * all frags to avoid possible bad checksum 441 */ 442 SKBTX_SHARED_FRAG = 1 << 5, 443 444 /* generate software time stamp when entering packet scheduling */ 445 SKBTX_SCHED_TSTAMP = 1 << 6, 446 }; 447 448 #define SKBTX_ZEROCOPY_FRAG (SKBTX_DEV_ZEROCOPY | SKBTX_SHARED_FRAG) 449 #define SKBTX_ANY_SW_TSTAMP (SKBTX_SW_TSTAMP | \ 450 SKBTX_SCHED_TSTAMP) 451 #define SKBTX_ANY_TSTAMP (SKBTX_HW_TSTAMP | SKBTX_ANY_SW_TSTAMP) 452 453 /* 454 * The callback notifies userspace to release buffers when skb DMA is done in 455 * lower device, the skb last reference should be 0 when calling this. 456 * The zerocopy_success argument is true if zero copy transmit occurred, 457 * false on data copy or out of memory error caused by data copy attempt. 458 * The ctx field is used to track device context. 459 * The desc field is used to track userspace buffer index. 460 */ 461 struct ubuf_info { 462 void (*callback)(struct ubuf_info *, bool zerocopy_success); 463 union { 464 struct { 465 unsigned long desc; 466 void *ctx; 467 }; 468 struct { 469 u32 id; 470 u16 len; 471 u16 zerocopy:1; 472 u32 bytelen; 473 }; 474 }; 475 refcount_t refcnt; 476 477 struct mmpin { 478 struct user_struct *user; 479 unsigned int num_pg; 480 } mmp; 481 }; 482 483 #define skb_uarg(SKB) ((struct ubuf_info *)(skb_shinfo(SKB)->destructor_arg)) 484 485 int mm_account_pinned_pages(struct mmpin *mmp, size_t size); 486 void mm_unaccount_pinned_pages(struct mmpin *mmp); 487 488 struct ubuf_info *sock_zerocopy_alloc(struct sock *sk, size_t size); 489 struct ubuf_info *sock_zerocopy_realloc(struct sock *sk, size_t size, 490 struct ubuf_info *uarg); 491 492 static inline void sock_zerocopy_get(struct ubuf_info *uarg) 493 { 494 refcount_inc(&uarg->refcnt); 495 } 496 497 void sock_zerocopy_put(struct ubuf_info *uarg); 498 void sock_zerocopy_put_abort(struct ubuf_info *uarg, bool have_uref); 499 500 void sock_zerocopy_callback(struct ubuf_info *uarg, bool success); 501 502 int skb_zerocopy_iter_dgram(struct sk_buff *skb, struct msghdr *msg, int len); 503 int skb_zerocopy_iter_stream(struct sock *sk, struct sk_buff *skb, 504 struct msghdr *msg, int len, 505 struct ubuf_info *uarg); 506 507 /* This data is invariant across clones and lives at 508 * the end of the header data, ie. at skb->end. 509 */ 510 struct skb_shared_info { 511 __u8 __unused; 512 __u8 meta_len; 513 __u8 nr_frags; 514 __u8 tx_flags; 515 unsigned short gso_size; 516 /* Warning: this field is not always filled in (UFO)! */ 517 unsigned short gso_segs; 518 struct sk_buff *frag_list; 519 struct skb_shared_hwtstamps hwtstamps; 520 unsigned int gso_type; 521 u32 tskey; 522 523 /* 524 * Warning : all fields before dataref are cleared in __alloc_skb() 525 */ 526 atomic_t dataref; 527 528 /* Intermediate layers must ensure that destructor_arg 529 * remains valid until skb destructor */ 530 void * destructor_arg; 531 532 /* must be last field, see pskb_expand_head() */ 533 skb_frag_t frags[MAX_SKB_FRAGS]; 534 }; 535 536 /* We divide dataref into two halves. The higher 16 bits hold references 537 * to the payload part of skb->data. The lower 16 bits hold references to 538 * the entire skb->data. A clone of a headerless skb holds the length of 539 * the header in skb->hdr_len. 540 * 541 * All users must obey the rule that the skb->data reference count must be 542 * greater than or equal to the payload reference count. 543 * 544 * Holding a reference to the payload part means that the user does not 545 * care about modifications to the header part of skb->data. 546 */ 547 #define SKB_DATAREF_SHIFT 16 548 #define SKB_DATAREF_MASK ((1 << SKB_DATAREF_SHIFT) - 1) 549 550 551 enum { 552 SKB_FCLONE_UNAVAILABLE, /* skb has no fclone (from head_cache) */ 553 SKB_FCLONE_ORIG, /* orig skb (from fclone_cache) */ 554 SKB_FCLONE_CLONE, /* companion fclone skb (from fclone_cache) */ 555 }; 556 557 enum { 558 SKB_GSO_TCPV4 = 1 << 0, 559 560 /* This indicates the skb is from an untrusted source. */ 561 SKB_GSO_DODGY = 1 << 1, 562 563 /* This indicates the tcp segment has CWR set. */ 564 SKB_GSO_TCP_ECN = 1 << 2, 565 566 SKB_GSO_TCP_FIXEDID = 1 << 3, 567 568 SKB_GSO_TCPV6 = 1 << 4, 569 570 SKB_GSO_FCOE = 1 << 5, 571 572 SKB_GSO_GRE = 1 << 6, 573 574 SKB_GSO_GRE_CSUM = 1 << 7, 575 576 SKB_GSO_IPXIP4 = 1 << 8, 577 578 SKB_GSO_IPXIP6 = 1 << 9, 579 580 SKB_GSO_UDP_TUNNEL = 1 << 10, 581 582 SKB_GSO_UDP_TUNNEL_CSUM = 1 << 11, 583 584 SKB_GSO_PARTIAL = 1 << 12, 585 586 SKB_GSO_TUNNEL_REMCSUM = 1 << 13, 587 588 SKB_GSO_SCTP = 1 << 14, 589 590 SKB_GSO_ESP = 1 << 15, 591 592 SKB_GSO_UDP = 1 << 16, 593 594 SKB_GSO_UDP_L4 = 1 << 17, 595 }; 596 597 #if BITS_PER_LONG > 32 598 #define NET_SKBUFF_DATA_USES_OFFSET 1 599 #endif 600 601 #ifdef NET_SKBUFF_DATA_USES_OFFSET 602 typedef unsigned int sk_buff_data_t; 603 #else 604 typedef unsigned char *sk_buff_data_t; 605 #endif 606 607 /** 608 * struct sk_buff - socket buffer 609 * @next: Next buffer in list 610 * @prev: Previous buffer in list 611 * @tstamp: Time we arrived/left 612 * @rbnode: RB tree node, alternative to next/prev for netem/tcp 613 * @sk: Socket we are owned by 614 * @dev: Device we arrived on/are leaving by 615 * @cb: Control buffer. Free for use by every layer. Put private vars here 616 * @_skb_refdst: destination entry (with norefcount bit) 617 * @sp: the security path, used for xfrm 618 * @len: Length of actual data 619 * @data_len: Data length 620 * @mac_len: Length of link layer header 621 * @hdr_len: writable header length of cloned skb 622 * @csum: Checksum (must include start/offset pair) 623 * @csum_start: Offset from skb->head where checksumming should start 624 * @csum_offset: Offset from csum_start where checksum should be stored 625 * @priority: Packet queueing priority 626 * @ignore_df: allow local fragmentation 627 * @cloned: Head may be cloned (check refcnt to be sure) 628 * @ip_summed: Driver fed us an IP checksum 629 * @nohdr: Payload reference only, must not modify header 630 * @pkt_type: Packet class 631 * @fclone: skbuff clone status 632 * @ipvs_property: skbuff is owned by ipvs 633 * @offload_fwd_mark: Packet was L2-forwarded in hardware 634 * @offload_l3_fwd_mark: Packet was L3-forwarded in hardware 635 * @tc_skip_classify: do not classify packet. set by IFB device 636 * @tc_at_ingress: used within tc_classify to distinguish in/egress 637 * @tc_redirected: packet was redirected by a tc action 638 * @tc_from_ingress: if tc_redirected, tc_at_ingress at time of redirect 639 * @peeked: this packet has been seen already, so stats have been 640 * done for it, don't do them again 641 * @nf_trace: netfilter packet trace flag 642 * @protocol: Packet protocol from driver 643 * @destructor: Destruct function 644 * @tcp_tsorted_anchor: list structure for TCP (tp->tsorted_sent_queue) 645 * @_nfct: Associated connection, if any (with nfctinfo bits) 646 * @nf_bridge: Saved data about a bridged frame - see br_netfilter.c 647 * @skb_iif: ifindex of device we arrived on 648 * @tc_index: Traffic control index 649 * @hash: the packet hash 650 * @queue_mapping: Queue mapping for multiqueue devices 651 * @pfmemalloc: skbuff was allocated from PFMEMALLOC reserves 652 * @active_extensions: active extensions (skb_ext_id types) 653 * @ndisc_nodetype: router type (from link layer) 654 * @ooo_okay: allow the mapping of a socket to a queue to be changed 655 * @l4_hash: indicate hash is a canonical 4-tuple hash over transport 656 * ports. 657 * @sw_hash: indicates hash was computed in software stack 658 * @wifi_acked_valid: wifi_acked was set 659 * @wifi_acked: whether frame was acked on wifi or not 660 * @no_fcs: Request NIC to treat last 4 bytes as Ethernet FCS 661 * @csum_not_inet: use CRC32c to resolve CHECKSUM_PARTIAL 662 * @dst_pending_confirm: need to confirm neighbour 663 * @decrypted: Decrypted SKB 664 * @napi_id: id of the NAPI struct this skb came from 665 * @secmark: security marking 666 * @mark: Generic packet mark 667 * @vlan_proto: vlan encapsulation protocol 668 * @vlan_tci: vlan tag control information 669 * @inner_protocol: Protocol (encapsulation) 670 * @inner_transport_header: Inner transport layer header (encapsulation) 671 * @inner_network_header: Network layer header (encapsulation) 672 * @inner_mac_header: Link layer header (encapsulation) 673 * @transport_header: Transport layer header 674 * @network_header: Network layer header 675 * @mac_header: Link layer header 676 * @tail: Tail pointer 677 * @end: End pointer 678 * @head: Head of buffer 679 * @data: Data head pointer 680 * @truesize: Buffer size 681 * @users: User count - see {datagram,tcp}.c 682 * @extensions: allocated extensions, valid if active_extensions is nonzero 683 */ 684 685 struct sk_buff { 686 union { 687 struct { 688 /* These two members must be first. */ 689 struct sk_buff *next; 690 struct sk_buff *prev; 691 692 union { 693 struct net_device *dev; 694 /* Some protocols might use this space to store information, 695 * while device pointer would be NULL. 696 * UDP receive path is one user. 697 */ 698 unsigned long dev_scratch; 699 }; 700 }; 701 struct rb_node rbnode; /* used in netem, ip4 defrag, and tcp stack */ 702 struct list_head list; 703 }; 704 705 union { 706 struct sock *sk; 707 int ip_defrag_offset; 708 }; 709 710 union { 711 ktime_t tstamp; 712 u64 skb_mstamp_ns; /* earliest departure time */ 713 }; 714 /* 715 * This is the control buffer. It is free to use for every 716 * layer. Please put your private variables there. If you 717 * want to keep them across layers you have to do a skb_clone() 718 * first. This is owned by whoever has the skb queued ATM. 719 */ 720 char cb[48] __aligned(8); 721 722 union { 723 struct { 724 unsigned long _skb_refdst; 725 void (*destructor)(struct sk_buff *skb); 726 }; 727 struct list_head tcp_tsorted_anchor; 728 }; 729 730 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE) 731 unsigned long _nfct; 732 #endif 733 unsigned int len, 734 data_len; 735 __u16 mac_len, 736 hdr_len; 737 738 /* Following fields are _not_ copied in __copy_skb_header() 739 * Note that queue_mapping is here mostly to fill a hole. 740 */ 741 __u16 queue_mapping; 742 743 /* if you move cloned around you also must adapt those constants */ 744 #ifdef __BIG_ENDIAN_BITFIELD 745 #define CLONED_MASK (1 << 7) 746 #else 747 #define CLONED_MASK 1 748 #endif 749 #define CLONED_OFFSET() offsetof(struct sk_buff, __cloned_offset) 750 751 __u8 __cloned_offset[0]; 752 __u8 cloned:1, 753 nohdr:1, 754 fclone:2, 755 peeked:1, 756 head_frag:1, 757 pfmemalloc:1; 758 #ifdef CONFIG_SKB_EXTENSIONS 759 __u8 active_extensions; 760 #endif 761 /* fields enclosed in headers_start/headers_end are copied 762 * using a single memcpy() in __copy_skb_header() 763 */ 764 /* private: */ 765 __u32 headers_start[0]; 766 /* public: */ 767 768 /* if you move pkt_type around you also must adapt those constants */ 769 #ifdef __BIG_ENDIAN_BITFIELD 770 #define PKT_TYPE_MAX (7 << 5) 771 #else 772 #define PKT_TYPE_MAX 7 773 #endif 774 #define PKT_TYPE_OFFSET() offsetof(struct sk_buff, __pkt_type_offset) 775 776 __u8 __pkt_type_offset[0]; 777 __u8 pkt_type:3; 778 __u8 ignore_df:1; 779 __u8 nf_trace:1; 780 __u8 ip_summed:2; 781 __u8 ooo_okay:1; 782 783 __u8 l4_hash:1; 784 __u8 sw_hash:1; 785 __u8 wifi_acked_valid:1; 786 __u8 wifi_acked:1; 787 __u8 no_fcs:1; 788 /* Indicates the inner headers are valid in the skbuff. */ 789 __u8 encapsulation:1; 790 __u8 encap_hdr_csum:1; 791 __u8 csum_valid:1; 792 793 #ifdef __BIG_ENDIAN_BITFIELD 794 #define PKT_VLAN_PRESENT_BIT 7 795 #else 796 #define PKT_VLAN_PRESENT_BIT 0 797 #endif 798 #define PKT_VLAN_PRESENT_OFFSET() offsetof(struct sk_buff, __pkt_vlan_present_offset) 799 __u8 __pkt_vlan_present_offset[0]; 800 __u8 vlan_present:1; 801 __u8 csum_complete_sw:1; 802 __u8 csum_level:2; 803 __u8 csum_not_inet:1; 804 __u8 dst_pending_confirm:1; 805 #ifdef CONFIG_IPV6_NDISC_NODETYPE 806 __u8 ndisc_nodetype:2; 807 #endif 808 809 __u8 ipvs_property:1; 810 __u8 inner_protocol_type:1; 811 __u8 remcsum_offload:1; 812 #ifdef CONFIG_NET_SWITCHDEV 813 __u8 offload_fwd_mark:1; 814 __u8 offload_l3_fwd_mark:1; 815 #endif 816 #ifdef CONFIG_NET_CLS_ACT 817 __u8 tc_skip_classify:1; 818 __u8 tc_at_ingress:1; 819 __u8 tc_redirected:1; 820 __u8 tc_from_ingress:1; 821 #endif 822 #ifdef CONFIG_TLS_DEVICE 823 __u8 decrypted:1; 824 #endif 825 826 #ifdef CONFIG_NET_SCHED 827 __u16 tc_index; /* traffic control index */ 828 #endif 829 830 union { 831 __wsum csum; 832 struct { 833 __u16 csum_start; 834 __u16 csum_offset; 835 }; 836 }; 837 __u32 priority; 838 int skb_iif; 839 __u32 hash; 840 __be16 vlan_proto; 841 __u16 vlan_tci; 842 #if defined(CONFIG_NET_RX_BUSY_POLL) || defined(CONFIG_XPS) 843 union { 844 unsigned int napi_id; 845 unsigned int sender_cpu; 846 }; 847 #endif 848 #ifdef CONFIG_NETWORK_SECMARK 849 __u32 secmark; 850 #endif 851 852 union { 853 __u32 mark; 854 __u32 reserved_tailroom; 855 }; 856 857 union { 858 __be16 inner_protocol; 859 __u8 inner_ipproto; 860 }; 861 862 __u16 inner_transport_header; 863 __u16 inner_network_header; 864 __u16 inner_mac_header; 865 866 __be16 protocol; 867 __u16 transport_header; 868 __u16 network_header; 869 __u16 mac_header; 870 871 /* private: */ 872 __u32 headers_end[0]; 873 /* public: */ 874 875 /* These elements must be at the end, see alloc_skb() for details. */ 876 sk_buff_data_t tail; 877 sk_buff_data_t end; 878 unsigned char *head, 879 *data; 880 unsigned int truesize; 881 refcount_t users; 882 883 #ifdef CONFIG_SKB_EXTENSIONS 884 /* only useable after checking ->active_extensions != 0 */ 885 struct skb_ext *extensions; 886 #endif 887 }; 888 889 #ifdef __KERNEL__ 890 /* 891 * Handling routines are only of interest to the kernel 892 */ 893 894 #define SKB_ALLOC_FCLONE 0x01 895 #define SKB_ALLOC_RX 0x02 896 #define SKB_ALLOC_NAPI 0x04 897 898 /** 899 * skb_pfmemalloc - Test if the skb was allocated from PFMEMALLOC reserves 900 * @skb: buffer 901 */ 902 static inline bool skb_pfmemalloc(const struct sk_buff *skb) 903 { 904 return unlikely(skb->pfmemalloc); 905 } 906 907 /* 908 * skb might have a dst pointer attached, refcounted or not. 909 * _skb_refdst low order bit is set if refcount was _not_ taken 910 */ 911 #define SKB_DST_NOREF 1UL 912 #define SKB_DST_PTRMASK ~(SKB_DST_NOREF) 913 914 /** 915 * skb_dst - returns skb dst_entry 916 * @skb: buffer 917 * 918 * Returns skb dst_entry, regardless of reference taken or not. 919 */ 920 static inline struct dst_entry *skb_dst(const struct sk_buff *skb) 921 { 922 /* If refdst was not refcounted, check we still are in a 923 * rcu_read_lock section 924 */ 925 WARN_ON((skb->_skb_refdst & SKB_DST_NOREF) && 926 !rcu_read_lock_held() && 927 !rcu_read_lock_bh_held()); 928 return (struct dst_entry *)(skb->_skb_refdst & SKB_DST_PTRMASK); 929 } 930 931 /** 932 * skb_dst_set - sets skb dst 933 * @skb: buffer 934 * @dst: dst entry 935 * 936 * Sets skb dst, assuming a reference was taken on dst and should 937 * be released by skb_dst_drop() 938 */ 939 static inline void skb_dst_set(struct sk_buff *skb, struct dst_entry *dst) 940 { 941 skb->_skb_refdst = (unsigned long)dst; 942 } 943 944 /** 945 * skb_dst_set_noref - sets skb dst, hopefully, without taking reference 946 * @skb: buffer 947 * @dst: dst entry 948 * 949 * Sets skb dst, assuming a reference was not taken on dst. 950 * If dst entry is cached, we do not take reference and dst_release 951 * will be avoided by refdst_drop. If dst entry is not cached, we take 952 * reference, so that last dst_release can destroy the dst immediately. 953 */ 954 static inline void skb_dst_set_noref(struct sk_buff *skb, struct dst_entry *dst) 955 { 956 WARN_ON(!rcu_read_lock_held() && !rcu_read_lock_bh_held()); 957 skb->_skb_refdst = (unsigned long)dst | SKB_DST_NOREF; 958 } 959 960 /** 961 * skb_dst_is_noref - Test if skb dst isn't refcounted 962 * @skb: buffer 963 */ 964 static inline bool skb_dst_is_noref(const struct sk_buff *skb) 965 { 966 return (skb->_skb_refdst & SKB_DST_NOREF) && skb_dst(skb); 967 } 968 969 /** 970 * skb_rtable - Returns the skb &rtable 971 * @skb: buffer 972 */ 973 static inline struct rtable *skb_rtable(const struct sk_buff *skb) 974 { 975 return (struct rtable *)skb_dst(skb); 976 } 977 978 /* For mangling skb->pkt_type from user space side from applications 979 * such as nft, tc, etc, we only allow a conservative subset of 980 * possible pkt_types to be set. 981 */ 982 static inline bool skb_pkt_type_ok(u32 ptype) 983 { 984 return ptype <= PACKET_OTHERHOST; 985 } 986 987 /** 988 * skb_napi_id - Returns the skb's NAPI id 989 * @skb: buffer 990 */ 991 static inline unsigned int skb_napi_id(const struct sk_buff *skb) 992 { 993 #ifdef CONFIG_NET_RX_BUSY_POLL 994 return skb->napi_id; 995 #else 996 return 0; 997 #endif 998 } 999 1000 /** 1001 * skb_unref - decrement the skb's reference count 1002 * @skb: buffer 1003 * 1004 * Returns true if we can free the skb. 1005 */ 1006 static inline bool skb_unref(struct sk_buff *skb) 1007 { 1008 if (unlikely(!skb)) 1009 return false; 1010 if (likely(refcount_read(&skb->users) == 1)) 1011 smp_rmb(); 1012 else if (likely(!refcount_dec_and_test(&skb->users))) 1013 return false; 1014 1015 return true; 1016 } 1017 1018 void skb_release_head_state(struct sk_buff *skb); 1019 void kfree_skb(struct sk_buff *skb); 1020 void kfree_skb_list(struct sk_buff *segs); 1021 void skb_dump(const char *level, const struct sk_buff *skb, bool full_pkt); 1022 void skb_tx_error(struct sk_buff *skb); 1023 void consume_skb(struct sk_buff *skb); 1024 void __consume_stateless_skb(struct sk_buff *skb); 1025 void __kfree_skb(struct sk_buff *skb); 1026 extern struct kmem_cache *skbuff_head_cache; 1027 1028 void kfree_skb_partial(struct sk_buff *skb, bool head_stolen); 1029 bool skb_try_coalesce(struct sk_buff *to, struct sk_buff *from, 1030 bool *fragstolen, int *delta_truesize); 1031 1032 struct sk_buff *__alloc_skb(unsigned int size, gfp_t priority, int flags, 1033 int node); 1034 struct sk_buff *__build_skb(void *data, unsigned int frag_size); 1035 struct sk_buff *build_skb(void *data, unsigned int frag_size); 1036 struct sk_buff *build_skb_around(struct sk_buff *skb, 1037 void *data, unsigned int frag_size); 1038 1039 /** 1040 * alloc_skb - allocate a network buffer 1041 * @size: size to allocate 1042 * @priority: allocation mask 1043 * 1044 * This function is a convenient wrapper around __alloc_skb(). 1045 */ 1046 static inline struct sk_buff *alloc_skb(unsigned int size, 1047 gfp_t priority) 1048 { 1049 return __alloc_skb(size, priority, 0, NUMA_NO_NODE); 1050 } 1051 1052 struct sk_buff *alloc_skb_with_frags(unsigned long header_len, 1053 unsigned long data_len, 1054 int max_page_order, 1055 int *errcode, 1056 gfp_t gfp_mask); 1057 struct sk_buff *alloc_skb_for_msg(struct sk_buff *first); 1058 1059 /* Layout of fast clones : [skb1][skb2][fclone_ref] */ 1060 struct sk_buff_fclones { 1061 struct sk_buff skb1; 1062 1063 struct sk_buff skb2; 1064 1065 refcount_t fclone_ref; 1066 }; 1067 1068 /** 1069 * skb_fclone_busy - check if fclone is busy 1070 * @sk: socket 1071 * @skb: buffer 1072 * 1073 * Returns true if skb is a fast clone, and its clone is not freed. 1074 * Some drivers call skb_orphan() in their ndo_start_xmit(), 1075 * so we also check that this didnt happen. 1076 */ 1077 static inline bool skb_fclone_busy(const struct sock *sk, 1078 const struct sk_buff *skb) 1079 { 1080 const struct sk_buff_fclones *fclones; 1081 1082 fclones = container_of(skb, struct sk_buff_fclones, skb1); 1083 1084 return skb->fclone == SKB_FCLONE_ORIG && 1085 refcount_read(&fclones->fclone_ref) > 1 && 1086 fclones->skb2.sk == sk; 1087 } 1088 1089 /** 1090 * alloc_skb_fclone - allocate a network buffer from fclone cache 1091 * @size: size to allocate 1092 * @priority: allocation mask 1093 * 1094 * This function is a convenient wrapper around __alloc_skb(). 1095 */ 1096 static inline struct sk_buff *alloc_skb_fclone(unsigned int size, 1097 gfp_t priority) 1098 { 1099 return __alloc_skb(size, priority, SKB_ALLOC_FCLONE, NUMA_NO_NODE); 1100 } 1101 1102 struct sk_buff *skb_morph(struct sk_buff *dst, struct sk_buff *src); 1103 void skb_headers_offset_update(struct sk_buff *skb, int off); 1104 int skb_copy_ubufs(struct sk_buff *skb, gfp_t gfp_mask); 1105 struct sk_buff *skb_clone(struct sk_buff *skb, gfp_t priority); 1106 void skb_copy_header(struct sk_buff *new, const struct sk_buff *old); 1107 struct sk_buff *skb_copy(const struct sk_buff *skb, gfp_t priority); 1108 struct sk_buff *__pskb_copy_fclone(struct sk_buff *skb, int headroom, 1109 gfp_t gfp_mask, bool fclone); 1110 static inline struct sk_buff *__pskb_copy(struct sk_buff *skb, int headroom, 1111 gfp_t gfp_mask) 1112 { 1113 return __pskb_copy_fclone(skb, headroom, gfp_mask, false); 1114 } 1115 1116 int pskb_expand_head(struct sk_buff *skb, int nhead, int ntail, gfp_t gfp_mask); 1117 struct sk_buff *skb_realloc_headroom(struct sk_buff *skb, 1118 unsigned int headroom); 1119 struct sk_buff *skb_copy_expand(const struct sk_buff *skb, int newheadroom, 1120 int newtailroom, gfp_t priority); 1121 int __must_check skb_to_sgvec_nomark(struct sk_buff *skb, struct scatterlist *sg, 1122 int offset, int len); 1123 int __must_check skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, 1124 int offset, int len); 1125 int skb_cow_data(struct sk_buff *skb, int tailbits, struct sk_buff **trailer); 1126 int __skb_pad(struct sk_buff *skb, int pad, bool free_on_error); 1127 1128 /** 1129 * skb_pad - zero pad the tail of an skb 1130 * @skb: buffer to pad 1131 * @pad: space to pad 1132 * 1133 * Ensure that a buffer is followed by a padding area that is zero 1134 * filled. Used by network drivers which may DMA or transfer data 1135 * beyond the buffer end onto the wire. 1136 * 1137 * May return error in out of memory cases. The skb is freed on error. 1138 */ 1139 static inline int skb_pad(struct sk_buff *skb, int pad) 1140 { 1141 return __skb_pad(skb, pad, true); 1142 } 1143 #define dev_kfree_skb(a) consume_skb(a) 1144 1145 int skb_append_pagefrags(struct sk_buff *skb, struct page *page, 1146 int offset, size_t size); 1147 1148 struct skb_seq_state { 1149 __u32 lower_offset; 1150 __u32 upper_offset; 1151 __u32 frag_idx; 1152 __u32 stepped_offset; 1153 struct sk_buff *root_skb; 1154 struct sk_buff *cur_skb; 1155 __u8 *frag_data; 1156 }; 1157 1158 void skb_prepare_seq_read(struct sk_buff *skb, unsigned int from, 1159 unsigned int to, struct skb_seq_state *st); 1160 unsigned int skb_seq_read(unsigned int consumed, const u8 **data, 1161 struct skb_seq_state *st); 1162 void skb_abort_seq_read(struct skb_seq_state *st); 1163 1164 unsigned int skb_find_text(struct sk_buff *skb, unsigned int from, 1165 unsigned int to, struct ts_config *config); 1166 1167 /* 1168 * Packet hash types specify the type of hash in skb_set_hash. 1169 * 1170 * Hash types refer to the protocol layer addresses which are used to 1171 * construct a packet's hash. The hashes are used to differentiate or identify 1172 * flows of the protocol layer for the hash type. Hash types are either 1173 * layer-2 (L2), layer-3 (L3), or layer-4 (L4). 1174 * 1175 * Properties of hashes: 1176 * 1177 * 1) Two packets in different flows have different hash values 1178 * 2) Two packets in the same flow should have the same hash value 1179 * 1180 * A hash at a higher layer is considered to be more specific. A driver should 1181 * set the most specific hash possible. 1182 * 1183 * A driver cannot indicate a more specific hash than the layer at which a hash 1184 * was computed. For instance an L3 hash cannot be set as an L4 hash. 1185 * 1186 * A driver may indicate a hash level which is less specific than the 1187 * actual layer the hash was computed on. For instance, a hash computed 1188 * at L4 may be considered an L3 hash. This should only be done if the 1189 * driver can't unambiguously determine that the HW computed the hash at 1190 * the higher layer. Note that the "should" in the second property above 1191 * permits this. 1192 */ 1193 enum pkt_hash_types { 1194 PKT_HASH_TYPE_NONE, /* Undefined type */ 1195 PKT_HASH_TYPE_L2, /* Input: src_MAC, dest_MAC */ 1196 PKT_HASH_TYPE_L3, /* Input: src_IP, dst_IP */ 1197 PKT_HASH_TYPE_L4, /* Input: src_IP, dst_IP, src_port, dst_port */ 1198 }; 1199 1200 static inline void skb_clear_hash(struct sk_buff *skb) 1201 { 1202 skb->hash = 0; 1203 skb->sw_hash = 0; 1204 skb->l4_hash = 0; 1205 } 1206 1207 static inline void skb_clear_hash_if_not_l4(struct sk_buff *skb) 1208 { 1209 if (!skb->l4_hash) 1210 skb_clear_hash(skb); 1211 } 1212 1213 static inline void 1214 __skb_set_hash(struct sk_buff *skb, __u32 hash, bool is_sw, bool is_l4) 1215 { 1216 skb->l4_hash = is_l4; 1217 skb->sw_hash = is_sw; 1218 skb->hash = hash; 1219 } 1220 1221 static inline void 1222 skb_set_hash(struct sk_buff *skb, __u32 hash, enum pkt_hash_types type) 1223 { 1224 /* Used by drivers to set hash from HW */ 1225 __skb_set_hash(skb, hash, false, type == PKT_HASH_TYPE_L4); 1226 } 1227 1228 static inline void 1229 __skb_set_sw_hash(struct sk_buff *skb, __u32 hash, bool is_l4) 1230 { 1231 __skb_set_hash(skb, hash, true, is_l4); 1232 } 1233 1234 void __skb_get_hash(struct sk_buff *skb); 1235 u32 __skb_get_hash_symmetric(const struct sk_buff *skb); 1236 u32 skb_get_poff(const struct sk_buff *skb); 1237 u32 __skb_get_poff(const struct sk_buff *skb, void *data, 1238 const struct flow_keys_basic *keys, int hlen); 1239 __be32 __skb_flow_get_ports(const struct sk_buff *skb, int thoff, u8 ip_proto, 1240 void *data, int hlen_proto); 1241 1242 static inline __be32 skb_flow_get_ports(const struct sk_buff *skb, 1243 int thoff, u8 ip_proto) 1244 { 1245 return __skb_flow_get_ports(skb, thoff, ip_proto, NULL, 0); 1246 } 1247 1248 void skb_flow_dissector_init(struct flow_dissector *flow_dissector, 1249 const struct flow_dissector_key *key, 1250 unsigned int key_count); 1251 1252 #ifdef CONFIG_NET 1253 int skb_flow_dissector_prog_query(const union bpf_attr *attr, 1254 union bpf_attr __user *uattr); 1255 int skb_flow_dissector_bpf_prog_attach(const union bpf_attr *attr, 1256 struct bpf_prog *prog); 1257 1258 int skb_flow_dissector_bpf_prog_detach(const union bpf_attr *attr); 1259 #else 1260 static inline int skb_flow_dissector_prog_query(const union bpf_attr *attr, 1261 union bpf_attr __user *uattr) 1262 { 1263 return -EOPNOTSUPP; 1264 } 1265 1266 static inline int skb_flow_dissector_bpf_prog_attach(const union bpf_attr *attr, 1267 struct bpf_prog *prog) 1268 { 1269 return -EOPNOTSUPP; 1270 } 1271 1272 static inline int skb_flow_dissector_bpf_prog_detach(const union bpf_attr *attr) 1273 { 1274 return -EOPNOTSUPP; 1275 } 1276 #endif 1277 1278 struct bpf_flow_dissector; 1279 bool bpf_flow_dissect(struct bpf_prog *prog, struct bpf_flow_dissector *ctx, 1280 __be16 proto, int nhoff, int hlen, unsigned int flags); 1281 1282 bool __skb_flow_dissect(const struct net *net, 1283 const struct sk_buff *skb, 1284 struct flow_dissector *flow_dissector, 1285 void *target_container, 1286 void *data, __be16 proto, int nhoff, int hlen, 1287 unsigned int flags); 1288 1289 static inline bool skb_flow_dissect(const struct sk_buff *skb, 1290 struct flow_dissector *flow_dissector, 1291 void *target_container, unsigned int flags) 1292 { 1293 return __skb_flow_dissect(NULL, skb, flow_dissector, 1294 target_container, NULL, 0, 0, 0, flags); 1295 } 1296 1297 static inline bool skb_flow_dissect_flow_keys(const struct sk_buff *skb, 1298 struct flow_keys *flow, 1299 unsigned int flags) 1300 { 1301 memset(flow, 0, sizeof(*flow)); 1302 return __skb_flow_dissect(NULL, skb, &flow_keys_dissector, 1303 flow, NULL, 0, 0, 0, flags); 1304 } 1305 1306 static inline bool 1307 skb_flow_dissect_flow_keys_basic(const struct net *net, 1308 const struct sk_buff *skb, 1309 struct flow_keys_basic *flow, void *data, 1310 __be16 proto, int nhoff, int hlen, 1311 unsigned int flags) 1312 { 1313 memset(flow, 0, sizeof(*flow)); 1314 return __skb_flow_dissect(net, skb, &flow_keys_basic_dissector, flow, 1315 data, proto, nhoff, hlen, flags); 1316 } 1317 1318 void skb_flow_dissect_meta(const struct sk_buff *skb, 1319 struct flow_dissector *flow_dissector, 1320 void *target_container); 1321 1322 /* Gets a skb connection tracking info, ctinfo map should be a 1323 * a map of mapsize to translate enum ip_conntrack_info states 1324 * to user states. 1325 */ 1326 void 1327 skb_flow_dissect_ct(const struct sk_buff *skb, 1328 struct flow_dissector *flow_dissector, 1329 void *target_container, 1330 u16 *ctinfo_map, 1331 size_t mapsize); 1332 void 1333 skb_flow_dissect_tunnel_info(const struct sk_buff *skb, 1334 struct flow_dissector *flow_dissector, 1335 void *target_container); 1336 1337 static inline __u32 skb_get_hash(struct sk_buff *skb) 1338 { 1339 if (!skb->l4_hash && !skb->sw_hash) 1340 __skb_get_hash(skb); 1341 1342 return skb->hash; 1343 } 1344 1345 static inline __u32 skb_get_hash_flowi6(struct sk_buff *skb, const struct flowi6 *fl6) 1346 { 1347 if (!skb->l4_hash && !skb->sw_hash) { 1348 struct flow_keys keys; 1349 __u32 hash = __get_hash_from_flowi6(fl6, &keys); 1350 1351 __skb_set_sw_hash(skb, hash, flow_keys_have_l4(&keys)); 1352 } 1353 1354 return skb->hash; 1355 } 1356 1357 __u32 skb_get_hash_perturb(const struct sk_buff *skb, 1358 const siphash_key_t *perturb); 1359 1360 static inline __u32 skb_get_hash_raw(const struct sk_buff *skb) 1361 { 1362 return skb->hash; 1363 } 1364 1365 static inline void skb_copy_hash(struct sk_buff *to, const struct sk_buff *from) 1366 { 1367 to->hash = from->hash; 1368 to->sw_hash = from->sw_hash; 1369 to->l4_hash = from->l4_hash; 1370 }; 1371 1372 static inline void skb_copy_decrypted(struct sk_buff *to, 1373 const struct sk_buff *from) 1374 { 1375 #ifdef CONFIG_TLS_DEVICE 1376 to->decrypted = from->decrypted; 1377 #endif 1378 } 1379 1380 #ifdef NET_SKBUFF_DATA_USES_OFFSET 1381 static inline unsigned char *skb_end_pointer(const struct sk_buff *skb) 1382 { 1383 return skb->head + skb->end; 1384 } 1385 1386 static inline unsigned int skb_end_offset(const struct sk_buff *skb) 1387 { 1388 return skb->end; 1389 } 1390 #else 1391 static inline unsigned char *skb_end_pointer(const struct sk_buff *skb) 1392 { 1393 return skb->end; 1394 } 1395 1396 static inline unsigned int skb_end_offset(const struct sk_buff *skb) 1397 { 1398 return skb->end - skb->head; 1399 } 1400 #endif 1401 1402 /* Internal */ 1403 #define skb_shinfo(SKB) ((struct skb_shared_info *)(skb_end_pointer(SKB))) 1404 1405 static inline struct skb_shared_hwtstamps *skb_hwtstamps(struct sk_buff *skb) 1406 { 1407 return &skb_shinfo(skb)->hwtstamps; 1408 } 1409 1410 static inline struct ubuf_info *skb_zcopy(struct sk_buff *skb) 1411 { 1412 bool is_zcopy = skb && skb_shinfo(skb)->tx_flags & SKBTX_DEV_ZEROCOPY; 1413 1414 return is_zcopy ? skb_uarg(skb) : NULL; 1415 } 1416 1417 static inline void skb_zcopy_set(struct sk_buff *skb, struct ubuf_info *uarg, 1418 bool *have_ref) 1419 { 1420 if (skb && uarg && !skb_zcopy(skb)) { 1421 if (unlikely(have_ref && *have_ref)) 1422 *have_ref = false; 1423 else 1424 sock_zerocopy_get(uarg); 1425 skb_shinfo(skb)->destructor_arg = uarg; 1426 skb_shinfo(skb)->tx_flags |= SKBTX_ZEROCOPY_FRAG; 1427 } 1428 } 1429 1430 static inline void skb_zcopy_set_nouarg(struct sk_buff *skb, void *val) 1431 { 1432 skb_shinfo(skb)->destructor_arg = (void *)((uintptr_t) val | 0x1UL); 1433 skb_shinfo(skb)->tx_flags |= SKBTX_ZEROCOPY_FRAG; 1434 } 1435 1436 static inline bool skb_zcopy_is_nouarg(struct sk_buff *skb) 1437 { 1438 return (uintptr_t) skb_shinfo(skb)->destructor_arg & 0x1UL; 1439 } 1440 1441 static inline void *skb_zcopy_get_nouarg(struct sk_buff *skb) 1442 { 1443 return (void *)((uintptr_t) skb_shinfo(skb)->destructor_arg & ~0x1UL); 1444 } 1445 1446 /* Release a reference on a zerocopy structure */ 1447 static inline void skb_zcopy_clear(struct sk_buff *skb, bool zerocopy) 1448 { 1449 struct ubuf_info *uarg = skb_zcopy(skb); 1450 1451 if (uarg) { 1452 if (skb_zcopy_is_nouarg(skb)) { 1453 /* no notification callback */ 1454 } else if (uarg->callback == sock_zerocopy_callback) { 1455 uarg->zerocopy = uarg->zerocopy && zerocopy; 1456 sock_zerocopy_put(uarg); 1457 } else { 1458 uarg->callback(uarg, zerocopy); 1459 } 1460 1461 skb_shinfo(skb)->tx_flags &= ~SKBTX_ZEROCOPY_FRAG; 1462 } 1463 } 1464 1465 /* Abort a zerocopy operation and revert zckey on error in send syscall */ 1466 static inline void skb_zcopy_abort(struct sk_buff *skb) 1467 { 1468 struct ubuf_info *uarg = skb_zcopy(skb); 1469 1470 if (uarg) { 1471 sock_zerocopy_put_abort(uarg, false); 1472 skb_shinfo(skb)->tx_flags &= ~SKBTX_ZEROCOPY_FRAG; 1473 } 1474 } 1475 1476 static inline void skb_mark_not_on_list(struct sk_buff *skb) 1477 { 1478 skb->next = NULL; 1479 } 1480 1481 static inline void skb_list_del_init(struct sk_buff *skb) 1482 { 1483 __list_del_entry(&skb->list); 1484 skb_mark_not_on_list(skb); 1485 } 1486 1487 /** 1488 * skb_queue_empty - check if a queue is empty 1489 * @list: queue head 1490 * 1491 * Returns true if the queue is empty, false otherwise. 1492 */ 1493 static inline int skb_queue_empty(const struct sk_buff_head *list) 1494 { 1495 return list->next == (const struct sk_buff *) list; 1496 } 1497 1498 /** 1499 * skb_queue_empty_lockless - check if a queue is empty 1500 * @list: queue head 1501 * 1502 * Returns true if the queue is empty, false otherwise. 1503 * This variant can be used in lockless contexts. 1504 */ 1505 static inline bool skb_queue_empty_lockless(const struct sk_buff_head *list) 1506 { 1507 return READ_ONCE(list->next) == (const struct sk_buff *) list; 1508 } 1509 1510 1511 /** 1512 * skb_queue_is_last - check if skb is the last entry in the queue 1513 * @list: queue head 1514 * @skb: buffer 1515 * 1516 * Returns true if @skb is the last buffer on the list. 1517 */ 1518 static inline bool skb_queue_is_last(const struct sk_buff_head *list, 1519 const struct sk_buff *skb) 1520 { 1521 return skb->next == (const struct sk_buff *) list; 1522 } 1523 1524 /** 1525 * skb_queue_is_first - check if skb is the first entry in the queue 1526 * @list: queue head 1527 * @skb: buffer 1528 * 1529 * Returns true if @skb is the first buffer on the list. 1530 */ 1531 static inline bool skb_queue_is_first(const struct sk_buff_head *list, 1532 const struct sk_buff *skb) 1533 { 1534 return skb->prev == (const struct sk_buff *) list; 1535 } 1536 1537 /** 1538 * skb_queue_next - return the next packet in the queue 1539 * @list: queue head 1540 * @skb: current buffer 1541 * 1542 * Return the next packet in @list after @skb. It is only valid to 1543 * call this if skb_queue_is_last() evaluates to false. 1544 */ 1545 static inline struct sk_buff *skb_queue_next(const struct sk_buff_head *list, 1546 const struct sk_buff *skb) 1547 { 1548 /* This BUG_ON may seem severe, but if we just return then we 1549 * are going to dereference garbage. 1550 */ 1551 BUG_ON(skb_queue_is_last(list, skb)); 1552 return skb->next; 1553 } 1554 1555 /** 1556 * skb_queue_prev - return the prev packet in the queue 1557 * @list: queue head 1558 * @skb: current buffer 1559 * 1560 * Return the prev packet in @list before @skb. It is only valid to 1561 * call this if skb_queue_is_first() evaluates to false. 1562 */ 1563 static inline struct sk_buff *skb_queue_prev(const struct sk_buff_head *list, 1564 const struct sk_buff *skb) 1565 { 1566 /* This BUG_ON may seem severe, but if we just return then we 1567 * are going to dereference garbage. 1568 */ 1569 BUG_ON(skb_queue_is_first(list, skb)); 1570 return skb->prev; 1571 } 1572 1573 /** 1574 * skb_get - reference buffer 1575 * @skb: buffer to reference 1576 * 1577 * Makes another reference to a socket buffer and returns a pointer 1578 * to the buffer. 1579 */ 1580 static inline struct sk_buff *skb_get(struct sk_buff *skb) 1581 { 1582 refcount_inc(&skb->users); 1583 return skb; 1584 } 1585 1586 /* 1587 * If users == 1, we are the only owner and can avoid redundant atomic changes. 1588 */ 1589 1590 /** 1591 * skb_cloned - is the buffer a clone 1592 * @skb: buffer to check 1593 * 1594 * Returns true if the buffer was generated with skb_clone() and is 1595 * one of multiple shared copies of the buffer. Cloned buffers are 1596 * shared data so must not be written to under normal circumstances. 1597 */ 1598 static inline int skb_cloned(const struct sk_buff *skb) 1599 { 1600 return skb->cloned && 1601 (atomic_read(&skb_shinfo(skb)->dataref) & SKB_DATAREF_MASK) != 1; 1602 } 1603 1604 static inline int skb_unclone(struct sk_buff *skb, gfp_t pri) 1605 { 1606 might_sleep_if(gfpflags_allow_blocking(pri)); 1607 1608 if (skb_cloned(skb)) 1609 return pskb_expand_head(skb, 0, 0, pri); 1610 1611 return 0; 1612 } 1613 1614 /** 1615 * skb_header_cloned - is the header a clone 1616 * @skb: buffer to check 1617 * 1618 * Returns true if modifying the header part of the buffer requires 1619 * the data to be copied. 1620 */ 1621 static inline int skb_header_cloned(const struct sk_buff *skb) 1622 { 1623 int dataref; 1624 1625 if (!skb->cloned) 1626 return 0; 1627 1628 dataref = atomic_read(&skb_shinfo(skb)->dataref); 1629 dataref = (dataref & SKB_DATAREF_MASK) - (dataref >> SKB_DATAREF_SHIFT); 1630 return dataref != 1; 1631 } 1632 1633 static inline int skb_header_unclone(struct sk_buff *skb, gfp_t pri) 1634 { 1635 might_sleep_if(gfpflags_allow_blocking(pri)); 1636 1637 if (skb_header_cloned(skb)) 1638 return pskb_expand_head(skb, 0, 0, pri); 1639 1640 return 0; 1641 } 1642 1643 /** 1644 * __skb_header_release - release reference to header 1645 * @skb: buffer to operate on 1646 */ 1647 static inline void __skb_header_release(struct sk_buff *skb) 1648 { 1649 skb->nohdr = 1; 1650 atomic_set(&skb_shinfo(skb)->dataref, 1 + (1 << SKB_DATAREF_SHIFT)); 1651 } 1652 1653 1654 /** 1655 * skb_shared - is the buffer shared 1656 * @skb: buffer to check 1657 * 1658 * Returns true if more than one person has a reference to this 1659 * buffer. 1660 */ 1661 static inline int skb_shared(const struct sk_buff *skb) 1662 { 1663 return refcount_read(&skb->users) != 1; 1664 } 1665 1666 /** 1667 * skb_share_check - check if buffer is shared and if so clone it 1668 * @skb: buffer to check 1669 * @pri: priority for memory allocation 1670 * 1671 * If the buffer is shared the buffer is cloned and the old copy 1672 * drops a reference. A new clone with a single reference is returned. 1673 * If the buffer is not shared the original buffer is returned. When 1674 * being called from interrupt status or with spinlocks held pri must 1675 * be GFP_ATOMIC. 1676 * 1677 * NULL is returned on a memory allocation failure. 1678 */ 1679 static inline struct sk_buff *skb_share_check(struct sk_buff *skb, gfp_t pri) 1680 { 1681 might_sleep_if(gfpflags_allow_blocking(pri)); 1682 if (skb_shared(skb)) { 1683 struct sk_buff *nskb = skb_clone(skb, pri); 1684 1685 if (likely(nskb)) 1686 consume_skb(skb); 1687 else 1688 kfree_skb(skb); 1689 skb = nskb; 1690 } 1691 return skb; 1692 } 1693 1694 /* 1695 * Copy shared buffers into a new sk_buff. We effectively do COW on 1696 * packets to handle cases where we have a local reader and forward 1697 * and a couple of other messy ones. The normal one is tcpdumping 1698 * a packet thats being forwarded. 1699 */ 1700 1701 /** 1702 * skb_unshare - make a copy of a shared buffer 1703 * @skb: buffer to check 1704 * @pri: priority for memory allocation 1705 * 1706 * If the socket buffer is a clone then this function creates a new 1707 * copy of the data, drops a reference count on the old copy and returns 1708 * the new copy with the reference count at 1. If the buffer is not a clone 1709 * the original buffer is returned. When called with a spinlock held or 1710 * from interrupt state @pri must be %GFP_ATOMIC 1711 * 1712 * %NULL is returned on a memory allocation failure. 1713 */ 1714 static inline struct sk_buff *skb_unshare(struct sk_buff *skb, 1715 gfp_t pri) 1716 { 1717 might_sleep_if(gfpflags_allow_blocking(pri)); 1718 if (skb_cloned(skb)) { 1719 struct sk_buff *nskb = skb_copy(skb, pri); 1720 1721 /* Free our shared copy */ 1722 if (likely(nskb)) 1723 consume_skb(skb); 1724 else 1725 kfree_skb(skb); 1726 skb = nskb; 1727 } 1728 return skb; 1729 } 1730 1731 /** 1732 * skb_peek - peek at the head of an &sk_buff_head 1733 * @list_: list to peek at 1734 * 1735 * Peek an &sk_buff. Unlike most other operations you _MUST_ 1736 * be careful with this one. A peek leaves the buffer on the 1737 * list and someone else may run off with it. You must hold 1738 * the appropriate locks or have a private queue to do this. 1739 * 1740 * Returns %NULL for an empty list or a pointer to the head element. 1741 * The reference count is not incremented and the reference is therefore 1742 * volatile. Use with caution. 1743 */ 1744 static inline struct sk_buff *skb_peek(const struct sk_buff_head *list_) 1745 { 1746 struct sk_buff *skb = list_->next; 1747 1748 if (skb == (struct sk_buff *)list_) 1749 skb = NULL; 1750 return skb; 1751 } 1752 1753 /** 1754 * __skb_peek - peek at the head of a non-empty &sk_buff_head 1755 * @list_: list to peek at 1756 * 1757 * Like skb_peek(), but the caller knows that the list is not empty. 1758 */ 1759 static inline struct sk_buff *__skb_peek(const struct sk_buff_head *list_) 1760 { 1761 return list_->next; 1762 } 1763 1764 /** 1765 * skb_peek_next - peek skb following the given one from a queue 1766 * @skb: skb to start from 1767 * @list_: list to peek at 1768 * 1769 * Returns %NULL when the end of the list is met or a pointer to the 1770 * next element. The reference count is not incremented and the 1771 * reference is therefore volatile. Use with caution. 1772 */ 1773 static inline struct sk_buff *skb_peek_next(struct sk_buff *skb, 1774 const struct sk_buff_head *list_) 1775 { 1776 struct sk_buff *next = skb->next; 1777 1778 if (next == (struct sk_buff *)list_) 1779 next = NULL; 1780 return next; 1781 } 1782 1783 /** 1784 * skb_peek_tail - peek at the tail of an &sk_buff_head 1785 * @list_: list to peek at 1786 * 1787 * Peek an &sk_buff. Unlike most other operations you _MUST_ 1788 * be careful with this one. A peek leaves the buffer on the 1789 * list and someone else may run off with it. You must hold 1790 * the appropriate locks or have a private queue to do this. 1791 * 1792 * Returns %NULL for an empty list or a pointer to the tail element. 1793 * The reference count is not incremented and the reference is therefore 1794 * volatile. Use with caution. 1795 */ 1796 static inline struct sk_buff *skb_peek_tail(const struct sk_buff_head *list_) 1797 { 1798 struct sk_buff *skb = READ_ONCE(list_->prev); 1799 1800 if (skb == (struct sk_buff *)list_) 1801 skb = NULL; 1802 return skb; 1803 1804 } 1805 1806 /** 1807 * skb_queue_len - get queue length 1808 * @list_: list to measure 1809 * 1810 * Return the length of an &sk_buff queue. 1811 */ 1812 static inline __u32 skb_queue_len(const struct sk_buff_head *list_) 1813 { 1814 return list_->qlen; 1815 } 1816 1817 /** 1818 * __skb_queue_head_init - initialize non-spinlock portions of sk_buff_head 1819 * @list: queue to initialize 1820 * 1821 * This initializes only the list and queue length aspects of 1822 * an sk_buff_head object. This allows to initialize the list 1823 * aspects of an sk_buff_head without reinitializing things like 1824 * the spinlock. It can also be used for on-stack sk_buff_head 1825 * objects where the spinlock is known to not be used. 1826 */ 1827 static inline void __skb_queue_head_init(struct sk_buff_head *list) 1828 { 1829 list->prev = list->next = (struct sk_buff *)list; 1830 list->qlen = 0; 1831 } 1832 1833 /* 1834 * This function creates a split out lock class for each invocation; 1835 * this is needed for now since a whole lot of users of the skb-queue 1836 * infrastructure in drivers have different locking usage (in hardirq) 1837 * than the networking core (in softirq only). In the long run either the 1838 * network layer or drivers should need annotation to consolidate the 1839 * main types of usage into 3 classes. 1840 */ 1841 static inline void skb_queue_head_init(struct sk_buff_head *list) 1842 { 1843 spin_lock_init(&list->lock); 1844 __skb_queue_head_init(list); 1845 } 1846 1847 static inline void skb_queue_head_init_class(struct sk_buff_head *list, 1848 struct lock_class_key *class) 1849 { 1850 skb_queue_head_init(list); 1851 lockdep_set_class(&list->lock, class); 1852 } 1853 1854 /* 1855 * Insert an sk_buff on a list. 1856 * 1857 * The "__skb_xxxx()" functions are the non-atomic ones that 1858 * can only be called with interrupts disabled. 1859 */ 1860 static inline void __skb_insert(struct sk_buff *newsk, 1861 struct sk_buff *prev, struct sk_buff *next, 1862 struct sk_buff_head *list) 1863 { 1864 /* See skb_queue_empty_lockless() and skb_peek_tail() 1865 * for the opposite READ_ONCE() 1866 */ 1867 WRITE_ONCE(newsk->next, next); 1868 WRITE_ONCE(newsk->prev, prev); 1869 WRITE_ONCE(next->prev, newsk); 1870 WRITE_ONCE(prev->next, newsk); 1871 list->qlen++; 1872 } 1873 1874 static inline void __skb_queue_splice(const struct sk_buff_head *list, 1875 struct sk_buff *prev, 1876 struct sk_buff *next) 1877 { 1878 struct sk_buff *first = list->next; 1879 struct sk_buff *last = list->prev; 1880 1881 WRITE_ONCE(first->prev, prev); 1882 WRITE_ONCE(prev->next, first); 1883 1884 WRITE_ONCE(last->next, next); 1885 WRITE_ONCE(next->prev, last); 1886 } 1887 1888 /** 1889 * skb_queue_splice - join two skb lists, this is designed for stacks 1890 * @list: the new list to add 1891 * @head: the place to add it in the first list 1892 */ 1893 static inline void skb_queue_splice(const struct sk_buff_head *list, 1894 struct sk_buff_head *head) 1895 { 1896 if (!skb_queue_empty(list)) { 1897 __skb_queue_splice(list, (struct sk_buff *) head, head->next); 1898 head->qlen += list->qlen; 1899 } 1900 } 1901 1902 /** 1903 * skb_queue_splice_init - join two skb lists and reinitialise the emptied list 1904 * @list: the new list to add 1905 * @head: the place to add it in the first list 1906 * 1907 * The list at @list is reinitialised 1908 */ 1909 static inline void skb_queue_splice_init(struct sk_buff_head *list, 1910 struct sk_buff_head *head) 1911 { 1912 if (!skb_queue_empty(list)) { 1913 __skb_queue_splice(list, (struct sk_buff *) head, head->next); 1914 head->qlen += list->qlen; 1915 __skb_queue_head_init(list); 1916 } 1917 } 1918 1919 /** 1920 * skb_queue_splice_tail - join two skb lists, each list being a queue 1921 * @list: the new list to add 1922 * @head: the place to add it in the first list 1923 */ 1924 static inline void skb_queue_splice_tail(const struct sk_buff_head *list, 1925 struct sk_buff_head *head) 1926 { 1927 if (!skb_queue_empty(list)) { 1928 __skb_queue_splice(list, head->prev, (struct sk_buff *) head); 1929 head->qlen += list->qlen; 1930 } 1931 } 1932 1933 /** 1934 * skb_queue_splice_tail_init - join two skb lists and reinitialise the emptied list 1935 * @list: the new list to add 1936 * @head: the place to add it in the first list 1937 * 1938 * Each of the lists is a queue. 1939 * The list at @list is reinitialised 1940 */ 1941 static inline void skb_queue_splice_tail_init(struct sk_buff_head *list, 1942 struct sk_buff_head *head) 1943 { 1944 if (!skb_queue_empty(list)) { 1945 __skb_queue_splice(list, head->prev, (struct sk_buff *) head); 1946 head->qlen += list->qlen; 1947 __skb_queue_head_init(list); 1948 } 1949 } 1950 1951 /** 1952 * __skb_queue_after - queue a buffer at the list head 1953 * @list: list to use 1954 * @prev: place after this buffer 1955 * @newsk: buffer to queue 1956 * 1957 * Queue a buffer int the middle of a list. This function takes no locks 1958 * and you must therefore hold required locks before calling it. 1959 * 1960 * A buffer cannot be placed on two lists at the same time. 1961 */ 1962 static inline void __skb_queue_after(struct sk_buff_head *list, 1963 struct sk_buff *prev, 1964 struct sk_buff *newsk) 1965 { 1966 __skb_insert(newsk, prev, prev->next, list); 1967 } 1968 1969 void skb_append(struct sk_buff *old, struct sk_buff *newsk, 1970 struct sk_buff_head *list); 1971 1972 static inline void __skb_queue_before(struct sk_buff_head *list, 1973 struct sk_buff *next, 1974 struct sk_buff *newsk) 1975 { 1976 __skb_insert(newsk, next->prev, next, list); 1977 } 1978 1979 /** 1980 * __skb_queue_head - queue a buffer at the list head 1981 * @list: list to use 1982 * @newsk: buffer to queue 1983 * 1984 * Queue a buffer at the start of a list. This function takes no locks 1985 * and you must therefore hold required locks before calling it. 1986 * 1987 * A buffer cannot be placed on two lists at the same time. 1988 */ 1989 static inline void __skb_queue_head(struct sk_buff_head *list, 1990 struct sk_buff *newsk) 1991 { 1992 __skb_queue_after(list, (struct sk_buff *)list, newsk); 1993 } 1994 void skb_queue_head(struct sk_buff_head *list, struct sk_buff *newsk); 1995 1996 /** 1997 * __skb_queue_tail - queue a buffer at the list tail 1998 * @list: list to use 1999 * @newsk: buffer to queue 2000 * 2001 * Queue a buffer at the end of a list. This function takes no locks 2002 * and you must therefore hold required locks before calling it. 2003 * 2004 * A buffer cannot be placed on two lists at the same time. 2005 */ 2006 static inline void __skb_queue_tail(struct sk_buff_head *list, 2007 struct sk_buff *newsk) 2008 { 2009 __skb_queue_before(list, (struct sk_buff *)list, newsk); 2010 } 2011 void skb_queue_tail(struct sk_buff_head *list, struct sk_buff *newsk); 2012 2013 /* 2014 * remove sk_buff from list. _Must_ be called atomically, and with 2015 * the list known.. 2016 */ 2017 void skb_unlink(struct sk_buff *skb, struct sk_buff_head *list); 2018 static inline void __skb_unlink(struct sk_buff *skb, struct sk_buff_head *list) 2019 { 2020 struct sk_buff *next, *prev; 2021 2022 list->qlen--; 2023 next = skb->next; 2024 prev = skb->prev; 2025 skb->next = skb->prev = NULL; 2026 WRITE_ONCE(next->prev, prev); 2027 WRITE_ONCE(prev->next, next); 2028 } 2029 2030 /** 2031 * __skb_dequeue - remove from the head of the queue 2032 * @list: list to dequeue from 2033 * 2034 * Remove the head of the list. This function does not take any locks 2035 * so must be used with appropriate locks held only. The head item is 2036 * returned or %NULL if the list is empty. 2037 */ 2038 static inline struct sk_buff *__skb_dequeue(struct sk_buff_head *list) 2039 { 2040 struct sk_buff *skb = skb_peek(list); 2041 if (skb) 2042 __skb_unlink(skb, list); 2043 return skb; 2044 } 2045 struct sk_buff *skb_dequeue(struct sk_buff_head *list); 2046 2047 /** 2048 * __skb_dequeue_tail - remove from the tail of the queue 2049 * @list: list to dequeue from 2050 * 2051 * Remove the tail of the list. This function does not take any locks 2052 * so must be used with appropriate locks held only. The tail item is 2053 * returned or %NULL if the list is empty. 2054 */ 2055 static inline struct sk_buff *__skb_dequeue_tail(struct sk_buff_head *list) 2056 { 2057 struct sk_buff *skb = skb_peek_tail(list); 2058 if (skb) 2059 __skb_unlink(skb, list); 2060 return skb; 2061 } 2062 struct sk_buff *skb_dequeue_tail(struct sk_buff_head *list); 2063 2064 2065 static inline bool skb_is_nonlinear(const struct sk_buff *skb) 2066 { 2067 return skb->data_len; 2068 } 2069 2070 static inline unsigned int skb_headlen(const struct sk_buff *skb) 2071 { 2072 return skb->len - skb->data_len; 2073 } 2074 2075 static inline unsigned int __skb_pagelen(const struct sk_buff *skb) 2076 { 2077 unsigned int i, len = 0; 2078 2079 for (i = skb_shinfo(skb)->nr_frags - 1; (int)i >= 0; i--) 2080 len += skb_frag_size(&skb_shinfo(skb)->frags[i]); 2081 return len; 2082 } 2083 2084 static inline unsigned int skb_pagelen(const struct sk_buff *skb) 2085 { 2086 return skb_headlen(skb) + __skb_pagelen(skb); 2087 } 2088 2089 /** 2090 * __skb_fill_page_desc - initialise a paged fragment in an skb 2091 * @skb: buffer containing fragment to be initialised 2092 * @i: paged fragment index to initialise 2093 * @page: the page to use for this fragment 2094 * @off: the offset to the data with @page 2095 * @size: the length of the data 2096 * 2097 * Initialises the @i'th fragment of @skb to point to &size bytes at 2098 * offset @off within @page. 2099 * 2100 * Does not take any additional reference on the fragment. 2101 */ 2102 static inline void __skb_fill_page_desc(struct sk_buff *skb, int i, 2103 struct page *page, int off, int size) 2104 { 2105 skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; 2106 2107 /* 2108 * Propagate page pfmemalloc to the skb if we can. The problem is 2109 * that not all callers have unique ownership of the page but rely 2110 * on page_is_pfmemalloc doing the right thing(tm). 2111 */ 2112 frag->bv_page = page; 2113 frag->bv_offset = off; 2114 skb_frag_size_set(frag, size); 2115 2116 page = compound_head(page); 2117 if (page_is_pfmemalloc(page)) 2118 skb->pfmemalloc = true; 2119 } 2120 2121 /** 2122 * skb_fill_page_desc - initialise a paged fragment in an skb 2123 * @skb: buffer containing fragment to be initialised 2124 * @i: paged fragment index to initialise 2125 * @page: the page to use for this fragment 2126 * @off: the offset to the data with @page 2127 * @size: the length of the data 2128 * 2129 * As per __skb_fill_page_desc() -- initialises the @i'th fragment of 2130 * @skb to point to @size bytes at offset @off within @page. In 2131 * addition updates @skb such that @i is the last fragment. 2132 * 2133 * Does not take any additional reference on the fragment. 2134 */ 2135 static inline void skb_fill_page_desc(struct sk_buff *skb, int i, 2136 struct page *page, int off, int size) 2137 { 2138 __skb_fill_page_desc(skb, i, page, off, size); 2139 skb_shinfo(skb)->nr_frags = i + 1; 2140 } 2141 2142 void skb_add_rx_frag(struct sk_buff *skb, int i, struct page *page, int off, 2143 int size, unsigned int truesize); 2144 2145 void skb_coalesce_rx_frag(struct sk_buff *skb, int i, int size, 2146 unsigned int truesize); 2147 2148 #define SKB_LINEAR_ASSERT(skb) BUG_ON(skb_is_nonlinear(skb)) 2149 2150 #ifdef NET_SKBUFF_DATA_USES_OFFSET 2151 static inline unsigned char *skb_tail_pointer(const struct sk_buff *skb) 2152 { 2153 return skb->head + skb->tail; 2154 } 2155 2156 static inline void skb_reset_tail_pointer(struct sk_buff *skb) 2157 { 2158 skb->tail = skb->data - skb->head; 2159 } 2160 2161 static inline void skb_set_tail_pointer(struct sk_buff *skb, const int offset) 2162 { 2163 skb_reset_tail_pointer(skb); 2164 skb->tail += offset; 2165 } 2166 2167 #else /* NET_SKBUFF_DATA_USES_OFFSET */ 2168 static inline unsigned char *skb_tail_pointer(const struct sk_buff *skb) 2169 { 2170 return skb->tail; 2171 } 2172 2173 static inline void skb_reset_tail_pointer(struct sk_buff *skb) 2174 { 2175 skb->tail = skb->data; 2176 } 2177 2178 static inline void skb_set_tail_pointer(struct sk_buff *skb, const int offset) 2179 { 2180 skb->tail = skb->data + offset; 2181 } 2182 2183 #endif /* NET_SKBUFF_DATA_USES_OFFSET */ 2184 2185 /* 2186 * Add data to an sk_buff 2187 */ 2188 void *pskb_put(struct sk_buff *skb, struct sk_buff *tail, int len); 2189 void *skb_put(struct sk_buff *skb, unsigned int len); 2190 static inline void *__skb_put(struct sk_buff *skb, unsigned int len) 2191 { 2192 void *tmp = skb_tail_pointer(skb); 2193 SKB_LINEAR_ASSERT(skb); 2194 skb->tail += len; 2195 skb->len += len; 2196 return tmp; 2197 } 2198 2199 static inline void *__skb_put_zero(struct sk_buff *skb, unsigned int len) 2200 { 2201 void *tmp = __skb_put(skb, len); 2202 2203 memset(tmp, 0, len); 2204 return tmp; 2205 } 2206 2207 static inline void *__skb_put_data(struct sk_buff *skb, const void *data, 2208 unsigned int len) 2209 { 2210 void *tmp = __skb_put(skb, len); 2211 2212 memcpy(tmp, data, len); 2213 return tmp; 2214 } 2215 2216 static inline void __skb_put_u8(struct sk_buff *skb, u8 val) 2217 { 2218 *(u8 *)__skb_put(skb, 1) = val; 2219 } 2220 2221 static inline void *skb_put_zero(struct sk_buff *skb, unsigned int len) 2222 { 2223 void *tmp = skb_put(skb, len); 2224 2225 memset(tmp, 0, len); 2226 2227 return tmp; 2228 } 2229 2230 static inline void *skb_put_data(struct sk_buff *skb, const void *data, 2231 unsigned int len) 2232 { 2233 void *tmp = skb_put(skb, len); 2234 2235 memcpy(tmp, data, len); 2236 2237 return tmp; 2238 } 2239 2240 static inline void skb_put_u8(struct sk_buff *skb, u8 val) 2241 { 2242 *(u8 *)skb_put(skb, 1) = val; 2243 } 2244 2245 void *skb_push(struct sk_buff *skb, unsigned int len); 2246 static inline void *__skb_push(struct sk_buff *skb, unsigned int len) 2247 { 2248 skb->data -= len; 2249 skb->len += len; 2250 return skb->data; 2251 } 2252 2253 void *skb_pull(struct sk_buff *skb, unsigned int len); 2254 static inline void *__skb_pull(struct sk_buff *skb, unsigned int len) 2255 { 2256 skb->len -= len; 2257 BUG_ON(skb->len < skb->data_len); 2258 return skb->data += len; 2259 } 2260 2261 static inline void *skb_pull_inline(struct sk_buff *skb, unsigned int len) 2262 { 2263 return unlikely(len > skb->len) ? NULL : __skb_pull(skb, len); 2264 } 2265 2266 void *__pskb_pull_tail(struct sk_buff *skb, int delta); 2267 2268 static inline void *__pskb_pull(struct sk_buff *skb, unsigned int len) 2269 { 2270 if (len > skb_headlen(skb) && 2271 !__pskb_pull_tail(skb, len - skb_headlen(skb))) 2272 return NULL; 2273 skb->len -= len; 2274 return skb->data += len; 2275 } 2276 2277 static inline void *pskb_pull(struct sk_buff *skb, unsigned int len) 2278 { 2279 return unlikely(len > skb->len) ? NULL : __pskb_pull(skb, len); 2280 } 2281 2282 static inline bool pskb_may_pull(struct sk_buff *skb, unsigned int len) 2283 { 2284 if (likely(len <= skb_headlen(skb))) 2285 return true; 2286 if (unlikely(len > skb->len)) 2287 return false; 2288 return __pskb_pull_tail(skb, len - skb_headlen(skb)) != NULL; 2289 } 2290 2291 void skb_condense(struct sk_buff *skb); 2292 2293 /** 2294 * skb_headroom - bytes at buffer head 2295 * @skb: buffer to check 2296 * 2297 * Return the number of bytes of free space at the head of an &sk_buff. 2298 */ 2299 static inline unsigned int skb_headroom(const struct sk_buff *skb) 2300 { 2301 return skb->data - skb->head; 2302 } 2303 2304 /** 2305 * skb_tailroom - bytes at buffer end 2306 * @skb: buffer to check 2307 * 2308 * Return the number of bytes of free space at the tail of an sk_buff 2309 */ 2310 static inline int skb_tailroom(const struct sk_buff *skb) 2311 { 2312 return skb_is_nonlinear(skb) ? 0 : skb->end - skb->tail; 2313 } 2314 2315 /** 2316 * skb_availroom - bytes at buffer end 2317 * @skb: buffer to check 2318 * 2319 * Return the number of bytes of free space at the tail of an sk_buff 2320 * allocated by sk_stream_alloc() 2321 */ 2322 static inline int skb_availroom(const struct sk_buff *skb) 2323 { 2324 if (skb_is_nonlinear(skb)) 2325 return 0; 2326 2327 return skb->end - skb->tail - skb->reserved_tailroom; 2328 } 2329 2330 /** 2331 * skb_reserve - adjust headroom 2332 * @skb: buffer to alter 2333 * @len: bytes to move 2334 * 2335 * Increase the headroom of an empty &sk_buff by reducing the tail 2336 * room. This is only allowed for an empty buffer. 2337 */ 2338 static inline void skb_reserve(struct sk_buff *skb, int len) 2339 { 2340 skb->data += len; 2341 skb->tail += len; 2342 } 2343 2344 /** 2345 * skb_tailroom_reserve - adjust reserved_tailroom 2346 * @skb: buffer to alter 2347 * @mtu: maximum amount of headlen permitted 2348 * @needed_tailroom: minimum amount of reserved_tailroom 2349 * 2350 * Set reserved_tailroom so that headlen can be as large as possible but 2351 * not larger than mtu and tailroom cannot be smaller than 2352 * needed_tailroom. 2353 * The required headroom should already have been reserved before using 2354 * this function. 2355 */ 2356 static inline void skb_tailroom_reserve(struct sk_buff *skb, unsigned int mtu, 2357 unsigned int needed_tailroom) 2358 { 2359 SKB_LINEAR_ASSERT(skb); 2360 if (mtu < skb_tailroom(skb) - needed_tailroom) 2361 /* use at most mtu */ 2362 skb->reserved_tailroom = skb_tailroom(skb) - mtu; 2363 else 2364 /* use up to all available space */ 2365 skb->reserved_tailroom = needed_tailroom; 2366 } 2367 2368 #define ENCAP_TYPE_ETHER 0 2369 #define ENCAP_TYPE_IPPROTO 1 2370 2371 static inline void skb_set_inner_protocol(struct sk_buff *skb, 2372 __be16 protocol) 2373 { 2374 skb->inner_protocol = protocol; 2375 skb->inner_protocol_type = ENCAP_TYPE_ETHER; 2376 } 2377 2378 static inline void skb_set_inner_ipproto(struct sk_buff *skb, 2379 __u8 ipproto) 2380 { 2381 skb->inner_ipproto = ipproto; 2382 skb->inner_protocol_type = ENCAP_TYPE_IPPROTO; 2383 } 2384 2385 static inline void skb_reset_inner_headers(struct sk_buff *skb) 2386 { 2387 skb->inner_mac_header = skb->mac_header; 2388 skb->inner_network_header = skb->network_header; 2389 skb->inner_transport_header = skb->transport_header; 2390 } 2391 2392 static inline void skb_reset_mac_len(struct sk_buff *skb) 2393 { 2394 skb->mac_len = skb->network_header - skb->mac_header; 2395 } 2396 2397 static inline unsigned char *skb_inner_transport_header(const struct sk_buff 2398 *skb) 2399 { 2400 return skb->head + skb->inner_transport_header; 2401 } 2402 2403 static inline int skb_inner_transport_offset(const struct sk_buff *skb) 2404 { 2405 return skb_inner_transport_header(skb) - skb->data; 2406 } 2407 2408 static inline void skb_reset_inner_transport_header(struct sk_buff *skb) 2409 { 2410 skb->inner_transport_header = skb->data - skb->head; 2411 } 2412 2413 static inline void skb_set_inner_transport_header(struct sk_buff *skb, 2414 const int offset) 2415 { 2416 skb_reset_inner_transport_header(skb); 2417 skb->inner_transport_header += offset; 2418 } 2419 2420 static inline unsigned char *skb_inner_network_header(const struct sk_buff *skb) 2421 { 2422 return skb->head + skb->inner_network_header; 2423 } 2424 2425 static inline void skb_reset_inner_network_header(struct sk_buff *skb) 2426 { 2427 skb->inner_network_header = skb->data - skb->head; 2428 } 2429 2430 static inline void skb_set_inner_network_header(struct sk_buff *skb, 2431 const int offset) 2432 { 2433 skb_reset_inner_network_header(skb); 2434 skb->inner_network_header += offset; 2435 } 2436 2437 static inline unsigned char *skb_inner_mac_header(const struct sk_buff *skb) 2438 { 2439 return skb->head + skb->inner_mac_header; 2440 } 2441 2442 static inline void skb_reset_inner_mac_header(struct sk_buff *skb) 2443 { 2444 skb->inner_mac_header = skb->data - skb->head; 2445 } 2446 2447 static inline void skb_set_inner_mac_header(struct sk_buff *skb, 2448 const int offset) 2449 { 2450 skb_reset_inner_mac_header(skb); 2451 skb->inner_mac_header += offset; 2452 } 2453 static inline bool skb_transport_header_was_set(const struct sk_buff *skb) 2454 { 2455 return skb->transport_header != (typeof(skb->transport_header))~0U; 2456 } 2457 2458 static inline unsigned char *skb_transport_header(const struct sk_buff *skb) 2459 { 2460 return skb->head + skb->transport_header; 2461 } 2462 2463 static inline void skb_reset_transport_header(struct sk_buff *skb) 2464 { 2465 skb->transport_header = skb->data - skb->head; 2466 } 2467 2468 static inline void skb_set_transport_header(struct sk_buff *skb, 2469 const int offset) 2470 { 2471 skb_reset_transport_header(skb); 2472 skb->transport_header += offset; 2473 } 2474 2475 static inline unsigned char *skb_network_header(const struct sk_buff *skb) 2476 { 2477 return skb->head + skb->network_header; 2478 } 2479 2480 static inline void skb_reset_network_header(struct sk_buff *skb) 2481 { 2482 skb->network_header = skb->data - skb->head; 2483 } 2484 2485 static inline void skb_set_network_header(struct sk_buff *skb, const int offset) 2486 { 2487 skb_reset_network_header(skb); 2488 skb->network_header += offset; 2489 } 2490 2491 static inline unsigned char *skb_mac_header(const struct sk_buff *skb) 2492 { 2493 return skb->head + skb->mac_header; 2494 } 2495 2496 static inline int skb_mac_offset(const struct sk_buff *skb) 2497 { 2498 return skb_mac_header(skb) - skb->data; 2499 } 2500 2501 static inline u32 skb_mac_header_len(const struct sk_buff *skb) 2502 { 2503 return skb->network_header - skb->mac_header; 2504 } 2505 2506 static inline int skb_mac_header_was_set(const struct sk_buff *skb) 2507 { 2508 return skb->mac_header != (typeof(skb->mac_header))~0U; 2509 } 2510 2511 static inline void skb_reset_mac_header(struct sk_buff *skb) 2512 { 2513 skb->mac_header = skb->data - skb->head; 2514 } 2515 2516 static inline void skb_set_mac_header(struct sk_buff *skb, const int offset) 2517 { 2518 skb_reset_mac_header(skb); 2519 skb->mac_header += offset; 2520 } 2521 2522 static inline void skb_pop_mac_header(struct sk_buff *skb) 2523 { 2524 skb->mac_header = skb->network_header; 2525 } 2526 2527 static inline void skb_probe_transport_header(struct sk_buff *skb) 2528 { 2529 struct flow_keys_basic keys; 2530 2531 if (skb_transport_header_was_set(skb)) 2532 return; 2533 2534 if (skb_flow_dissect_flow_keys_basic(NULL, skb, &keys, 2535 NULL, 0, 0, 0, 0)) 2536 skb_set_transport_header(skb, keys.control.thoff); 2537 } 2538 2539 static inline void skb_mac_header_rebuild(struct sk_buff *skb) 2540 { 2541 if (skb_mac_header_was_set(skb)) { 2542 const unsigned char *old_mac = skb_mac_header(skb); 2543 2544 skb_set_mac_header(skb, -skb->mac_len); 2545 memmove(skb_mac_header(skb), old_mac, skb->mac_len); 2546 } 2547 } 2548 2549 static inline int skb_checksum_start_offset(const struct sk_buff *skb) 2550 { 2551 return skb->csum_start - skb_headroom(skb); 2552 } 2553 2554 static inline unsigned char *skb_checksum_start(const struct sk_buff *skb) 2555 { 2556 return skb->head + skb->csum_start; 2557 } 2558 2559 static inline int skb_transport_offset(const struct sk_buff *skb) 2560 { 2561 return skb_transport_header(skb) - skb->data; 2562 } 2563 2564 static inline u32 skb_network_header_len(const struct sk_buff *skb) 2565 { 2566 return skb->transport_header - skb->network_header; 2567 } 2568 2569 static inline u32 skb_inner_network_header_len(const struct sk_buff *skb) 2570 { 2571 return skb->inner_transport_header - skb->inner_network_header; 2572 } 2573 2574 static inline int skb_network_offset(const struct sk_buff *skb) 2575 { 2576 return skb_network_header(skb) - skb->data; 2577 } 2578 2579 static inline int skb_inner_network_offset(const struct sk_buff *skb) 2580 { 2581 return skb_inner_network_header(skb) - skb->data; 2582 } 2583 2584 static inline int pskb_network_may_pull(struct sk_buff *skb, unsigned int len) 2585 { 2586 return pskb_may_pull(skb, skb_network_offset(skb) + len); 2587 } 2588 2589 /* 2590 * CPUs often take a performance hit when accessing unaligned memory 2591 * locations. The actual performance hit varies, it can be small if the 2592 * hardware handles it or large if we have to take an exception and fix it 2593 * in software. 2594 * 2595 * Since an ethernet header is 14 bytes network drivers often end up with 2596 * the IP header at an unaligned offset. The IP header can be aligned by 2597 * shifting the start of the packet by 2 bytes. Drivers should do this 2598 * with: 2599 * 2600 * skb_reserve(skb, NET_IP_ALIGN); 2601 * 2602 * The downside to this alignment of the IP header is that the DMA is now 2603 * unaligned. On some architectures the cost of an unaligned DMA is high 2604 * and this cost outweighs the gains made by aligning the IP header. 2605 * 2606 * Since this trade off varies between architectures, we allow NET_IP_ALIGN 2607 * to be overridden. 2608 */ 2609 #ifndef NET_IP_ALIGN 2610 #define NET_IP_ALIGN 2 2611 #endif 2612 2613 /* 2614 * The networking layer reserves some headroom in skb data (via 2615 * dev_alloc_skb). This is used to avoid having to reallocate skb data when 2616 * the header has to grow. In the default case, if the header has to grow 2617 * 32 bytes or less we avoid the reallocation. 2618 * 2619 * Unfortunately this headroom changes the DMA alignment of the resulting 2620 * network packet. As for NET_IP_ALIGN, this unaligned DMA is expensive 2621 * on some architectures. An architecture can override this value, 2622 * perhaps setting it to a cacheline in size (since that will maintain 2623 * cacheline alignment of the DMA). It must be a power of 2. 2624 * 2625 * Various parts of the networking layer expect at least 32 bytes of 2626 * headroom, you should not reduce this. 2627 * 2628 * Using max(32, L1_CACHE_BYTES) makes sense (especially with RPS) 2629 * to reduce average number of cache lines per packet. 2630 * get_rps_cpus() for example only access one 64 bytes aligned block : 2631 * NET_IP_ALIGN(2) + ethernet_header(14) + IP_header(20/40) + ports(8) 2632 */ 2633 #ifndef NET_SKB_PAD 2634 #define NET_SKB_PAD max(32, L1_CACHE_BYTES) 2635 #endif 2636 2637 int ___pskb_trim(struct sk_buff *skb, unsigned int len); 2638 2639 static inline void __skb_set_length(struct sk_buff *skb, unsigned int len) 2640 { 2641 if (WARN_ON(skb_is_nonlinear(skb))) 2642 return; 2643 skb->len = len; 2644 skb_set_tail_pointer(skb, len); 2645 } 2646 2647 static inline void __skb_trim(struct sk_buff *skb, unsigned int len) 2648 { 2649 __skb_set_length(skb, len); 2650 } 2651 2652 void skb_trim(struct sk_buff *skb, unsigned int len); 2653 2654 static inline int __pskb_trim(struct sk_buff *skb, unsigned int len) 2655 { 2656 if (skb->data_len) 2657 return ___pskb_trim(skb, len); 2658 __skb_trim(skb, len); 2659 return 0; 2660 } 2661 2662 static inline int pskb_trim(struct sk_buff *skb, unsigned int len) 2663 { 2664 return (len < skb->len) ? __pskb_trim(skb, len) : 0; 2665 } 2666 2667 /** 2668 * pskb_trim_unique - remove end from a paged unique (not cloned) buffer 2669 * @skb: buffer to alter 2670 * @len: new length 2671 * 2672 * This is identical to pskb_trim except that the caller knows that 2673 * the skb is not cloned so we should never get an error due to out- 2674 * of-memory. 2675 */ 2676 static inline void pskb_trim_unique(struct sk_buff *skb, unsigned int len) 2677 { 2678 int err = pskb_trim(skb, len); 2679 BUG_ON(err); 2680 } 2681 2682 static inline int __skb_grow(struct sk_buff *skb, unsigned int len) 2683 { 2684 unsigned int diff = len - skb->len; 2685 2686 if (skb_tailroom(skb) < diff) { 2687 int ret = pskb_expand_head(skb, 0, diff - skb_tailroom(skb), 2688 GFP_ATOMIC); 2689 if (ret) 2690 return ret; 2691 } 2692 __skb_set_length(skb, len); 2693 return 0; 2694 } 2695 2696 /** 2697 * skb_orphan - orphan a buffer 2698 * @skb: buffer to orphan 2699 * 2700 * If a buffer currently has an owner then we call the owner's 2701 * destructor function and make the @skb unowned. The buffer continues 2702 * to exist but is no longer charged to its former owner. 2703 */ 2704 static inline void skb_orphan(struct sk_buff *skb) 2705 { 2706 if (skb->destructor) { 2707 skb->destructor(skb); 2708 skb->destructor = NULL; 2709 skb->sk = NULL; 2710 } else { 2711 BUG_ON(skb->sk); 2712 } 2713 } 2714 2715 /** 2716 * skb_orphan_frags - orphan the frags contained in a buffer 2717 * @skb: buffer to orphan frags from 2718 * @gfp_mask: allocation mask for replacement pages 2719 * 2720 * For each frag in the SKB which needs a destructor (i.e. has an 2721 * owner) create a copy of that frag and release the original 2722 * page by calling the destructor. 2723 */ 2724 static inline int skb_orphan_frags(struct sk_buff *skb, gfp_t gfp_mask) 2725 { 2726 if (likely(!skb_zcopy(skb))) 2727 return 0; 2728 if (!skb_zcopy_is_nouarg(skb) && 2729 skb_uarg(skb)->callback == sock_zerocopy_callback) 2730 return 0; 2731 return skb_copy_ubufs(skb, gfp_mask); 2732 } 2733 2734 /* Frags must be orphaned, even if refcounted, if skb might loop to rx path */ 2735 static inline int skb_orphan_frags_rx(struct sk_buff *skb, gfp_t gfp_mask) 2736 { 2737 if (likely(!skb_zcopy(skb))) 2738 return 0; 2739 return skb_copy_ubufs(skb, gfp_mask); 2740 } 2741 2742 /** 2743 * __skb_queue_purge - empty a list 2744 * @list: list to empty 2745 * 2746 * Delete all buffers on an &sk_buff list. Each buffer is removed from 2747 * the list and one reference dropped. This function does not take the 2748 * list lock and the caller must hold the relevant locks to use it. 2749 */ 2750 static inline void __skb_queue_purge(struct sk_buff_head *list) 2751 { 2752 struct sk_buff *skb; 2753 while ((skb = __skb_dequeue(list)) != NULL) 2754 kfree_skb(skb); 2755 } 2756 void skb_queue_purge(struct sk_buff_head *list); 2757 2758 unsigned int skb_rbtree_purge(struct rb_root *root); 2759 2760 void *netdev_alloc_frag(unsigned int fragsz); 2761 2762 struct sk_buff *__netdev_alloc_skb(struct net_device *dev, unsigned int length, 2763 gfp_t gfp_mask); 2764 2765 /** 2766 * netdev_alloc_skb - allocate an skbuff for rx on a specific device 2767 * @dev: network device to receive on 2768 * @length: length to allocate 2769 * 2770 * Allocate a new &sk_buff and assign it a usage count of one. The 2771 * buffer has unspecified headroom built in. Users should allocate 2772 * the headroom they think they need without accounting for the 2773 * built in space. The built in space is used for optimisations. 2774 * 2775 * %NULL is returned if there is no free memory. Although this function 2776 * allocates memory it can be called from an interrupt. 2777 */ 2778 static inline struct sk_buff *netdev_alloc_skb(struct net_device *dev, 2779 unsigned int length) 2780 { 2781 return __netdev_alloc_skb(dev, length, GFP_ATOMIC); 2782 } 2783 2784 /* legacy helper around __netdev_alloc_skb() */ 2785 static inline struct sk_buff *__dev_alloc_skb(unsigned int length, 2786 gfp_t gfp_mask) 2787 { 2788 return __netdev_alloc_skb(NULL, length, gfp_mask); 2789 } 2790 2791 /* legacy helper around netdev_alloc_skb() */ 2792 static inline struct sk_buff *dev_alloc_skb(unsigned int length) 2793 { 2794 return netdev_alloc_skb(NULL, length); 2795 } 2796 2797 2798 static inline struct sk_buff *__netdev_alloc_skb_ip_align(struct net_device *dev, 2799 unsigned int length, gfp_t gfp) 2800 { 2801 struct sk_buff *skb = __netdev_alloc_skb(dev, length + NET_IP_ALIGN, gfp); 2802 2803 if (NET_IP_ALIGN && skb) 2804 skb_reserve(skb, NET_IP_ALIGN); 2805 return skb; 2806 } 2807 2808 static inline struct sk_buff *netdev_alloc_skb_ip_align(struct net_device *dev, 2809 unsigned int length) 2810 { 2811 return __netdev_alloc_skb_ip_align(dev, length, GFP_ATOMIC); 2812 } 2813 2814 static inline void skb_free_frag(void *addr) 2815 { 2816 page_frag_free(addr); 2817 } 2818 2819 void *napi_alloc_frag(unsigned int fragsz); 2820 struct sk_buff *__napi_alloc_skb(struct napi_struct *napi, 2821 unsigned int length, gfp_t gfp_mask); 2822 static inline struct sk_buff *napi_alloc_skb(struct napi_struct *napi, 2823 unsigned int length) 2824 { 2825 return __napi_alloc_skb(napi, length, GFP_ATOMIC); 2826 } 2827 void napi_consume_skb(struct sk_buff *skb, int budget); 2828 2829 void __kfree_skb_flush(void); 2830 void __kfree_skb_defer(struct sk_buff *skb); 2831 2832 /** 2833 * __dev_alloc_pages - allocate page for network Rx 2834 * @gfp_mask: allocation priority. Set __GFP_NOMEMALLOC if not for network Rx 2835 * @order: size of the allocation 2836 * 2837 * Allocate a new page. 2838 * 2839 * %NULL is returned if there is no free memory. 2840 */ 2841 static inline struct page *__dev_alloc_pages(gfp_t gfp_mask, 2842 unsigned int order) 2843 { 2844 /* This piece of code contains several assumptions. 2845 * 1. This is for device Rx, therefor a cold page is preferred. 2846 * 2. The expectation is the user wants a compound page. 2847 * 3. If requesting a order 0 page it will not be compound 2848 * due to the check to see if order has a value in prep_new_page 2849 * 4. __GFP_MEMALLOC is ignored if __GFP_NOMEMALLOC is set due to 2850 * code in gfp_to_alloc_flags that should be enforcing this. 2851 */ 2852 gfp_mask |= __GFP_COMP | __GFP_MEMALLOC; 2853 2854 return alloc_pages_node(NUMA_NO_NODE, gfp_mask, order); 2855 } 2856 2857 static inline struct page *dev_alloc_pages(unsigned int order) 2858 { 2859 return __dev_alloc_pages(GFP_ATOMIC | __GFP_NOWARN, order); 2860 } 2861 2862 /** 2863 * __dev_alloc_page - allocate a page for network Rx 2864 * @gfp_mask: allocation priority. Set __GFP_NOMEMALLOC if not for network Rx 2865 * 2866 * Allocate a new page. 2867 * 2868 * %NULL is returned if there is no free memory. 2869 */ 2870 static inline struct page *__dev_alloc_page(gfp_t gfp_mask) 2871 { 2872 return __dev_alloc_pages(gfp_mask, 0); 2873 } 2874 2875 static inline struct page *dev_alloc_page(void) 2876 { 2877 return dev_alloc_pages(0); 2878 } 2879 2880 /** 2881 * skb_propagate_pfmemalloc - Propagate pfmemalloc if skb is allocated after RX page 2882 * @page: The page that was allocated from skb_alloc_page 2883 * @skb: The skb that may need pfmemalloc set 2884 */ 2885 static inline void skb_propagate_pfmemalloc(struct page *page, 2886 struct sk_buff *skb) 2887 { 2888 if (page_is_pfmemalloc(page)) 2889 skb->pfmemalloc = true; 2890 } 2891 2892 /** 2893 * skb_frag_off() - Returns the offset of a skb fragment 2894 * @frag: the paged fragment 2895 */ 2896 static inline unsigned int skb_frag_off(const skb_frag_t *frag) 2897 { 2898 return frag->bv_offset; 2899 } 2900 2901 /** 2902 * skb_frag_off_add() - Increments the offset of a skb fragment by @delta 2903 * @frag: skb fragment 2904 * @delta: value to add 2905 */ 2906 static inline void skb_frag_off_add(skb_frag_t *frag, int delta) 2907 { 2908 frag->bv_offset += delta; 2909 } 2910 2911 /** 2912 * skb_frag_off_set() - Sets the offset of a skb fragment 2913 * @frag: skb fragment 2914 * @offset: offset of fragment 2915 */ 2916 static inline void skb_frag_off_set(skb_frag_t *frag, unsigned int offset) 2917 { 2918 frag->bv_offset = offset; 2919 } 2920 2921 /** 2922 * skb_frag_off_copy() - Sets the offset of a skb fragment from another fragment 2923 * @fragto: skb fragment where offset is set 2924 * @fragfrom: skb fragment offset is copied from 2925 */ 2926 static inline void skb_frag_off_copy(skb_frag_t *fragto, 2927 const skb_frag_t *fragfrom) 2928 { 2929 fragto->bv_offset = fragfrom->bv_offset; 2930 } 2931 2932 /** 2933 * skb_frag_page - retrieve the page referred to by a paged fragment 2934 * @frag: the paged fragment 2935 * 2936 * Returns the &struct page associated with @frag. 2937 */ 2938 static inline struct page *skb_frag_page(const skb_frag_t *frag) 2939 { 2940 return frag->bv_page; 2941 } 2942 2943 /** 2944 * __skb_frag_ref - take an addition reference on a paged fragment. 2945 * @frag: the paged fragment 2946 * 2947 * Takes an additional reference on the paged fragment @frag. 2948 */ 2949 static inline void __skb_frag_ref(skb_frag_t *frag) 2950 { 2951 get_page(skb_frag_page(frag)); 2952 } 2953 2954 /** 2955 * skb_frag_ref - take an addition reference on a paged fragment of an skb. 2956 * @skb: the buffer 2957 * @f: the fragment offset. 2958 * 2959 * Takes an additional reference on the @f'th paged fragment of @skb. 2960 */ 2961 static inline void skb_frag_ref(struct sk_buff *skb, int f) 2962 { 2963 __skb_frag_ref(&skb_shinfo(skb)->frags[f]); 2964 } 2965 2966 /** 2967 * __skb_frag_unref - release a reference on a paged fragment. 2968 * @frag: the paged fragment 2969 * 2970 * Releases a reference on the paged fragment @frag. 2971 */ 2972 static inline void __skb_frag_unref(skb_frag_t *frag) 2973 { 2974 put_page(skb_frag_page(frag)); 2975 } 2976 2977 /** 2978 * skb_frag_unref - release a reference on a paged fragment of an skb. 2979 * @skb: the buffer 2980 * @f: the fragment offset 2981 * 2982 * Releases a reference on the @f'th paged fragment of @skb. 2983 */ 2984 static inline void skb_frag_unref(struct sk_buff *skb, int f) 2985 { 2986 __skb_frag_unref(&skb_shinfo(skb)->frags[f]); 2987 } 2988 2989 /** 2990 * skb_frag_address - gets the address of the data contained in a paged fragment 2991 * @frag: the paged fragment buffer 2992 * 2993 * Returns the address of the data within @frag. The page must already 2994 * be mapped. 2995 */ 2996 static inline void *skb_frag_address(const skb_frag_t *frag) 2997 { 2998 return page_address(skb_frag_page(frag)) + skb_frag_off(frag); 2999 } 3000 3001 /** 3002 * skb_frag_address_safe - gets the address of the data contained in a paged fragment 3003 * @frag: the paged fragment buffer 3004 * 3005 * Returns the address of the data within @frag. Checks that the page 3006 * is mapped and returns %NULL otherwise. 3007 */ 3008 static inline void *skb_frag_address_safe(const skb_frag_t *frag) 3009 { 3010 void *ptr = page_address(skb_frag_page(frag)); 3011 if (unlikely(!ptr)) 3012 return NULL; 3013 3014 return ptr + skb_frag_off(frag); 3015 } 3016 3017 /** 3018 * skb_frag_page_copy() - sets the page in a fragment from another fragment 3019 * @fragto: skb fragment where page is set 3020 * @fragfrom: skb fragment page is copied from 3021 */ 3022 static inline void skb_frag_page_copy(skb_frag_t *fragto, 3023 const skb_frag_t *fragfrom) 3024 { 3025 fragto->bv_page = fragfrom->bv_page; 3026 } 3027 3028 /** 3029 * __skb_frag_set_page - sets the page contained in a paged fragment 3030 * @frag: the paged fragment 3031 * @page: the page to set 3032 * 3033 * Sets the fragment @frag to contain @page. 3034 */ 3035 static inline void __skb_frag_set_page(skb_frag_t *frag, struct page *page) 3036 { 3037 frag->bv_page = page; 3038 } 3039 3040 /** 3041 * skb_frag_set_page - sets the page contained in a paged fragment of an skb 3042 * @skb: the buffer 3043 * @f: the fragment offset 3044 * @page: the page to set 3045 * 3046 * Sets the @f'th fragment of @skb to contain @page. 3047 */ 3048 static inline void skb_frag_set_page(struct sk_buff *skb, int f, 3049 struct page *page) 3050 { 3051 __skb_frag_set_page(&skb_shinfo(skb)->frags[f], page); 3052 } 3053 3054 bool skb_page_frag_refill(unsigned int sz, struct page_frag *pfrag, gfp_t prio); 3055 3056 /** 3057 * skb_frag_dma_map - maps a paged fragment via the DMA API 3058 * @dev: the device to map the fragment to 3059 * @frag: the paged fragment to map 3060 * @offset: the offset within the fragment (starting at the 3061 * fragment's own offset) 3062 * @size: the number of bytes to map 3063 * @dir: the direction of the mapping (``PCI_DMA_*``) 3064 * 3065 * Maps the page associated with @frag to @device. 3066 */ 3067 static inline dma_addr_t skb_frag_dma_map(struct device *dev, 3068 const skb_frag_t *frag, 3069 size_t offset, size_t size, 3070 enum dma_data_direction dir) 3071 { 3072 return dma_map_page(dev, skb_frag_page(frag), 3073 skb_frag_off(frag) + offset, size, dir); 3074 } 3075 3076 static inline struct sk_buff *pskb_copy(struct sk_buff *skb, 3077 gfp_t gfp_mask) 3078 { 3079 return __pskb_copy(skb, skb_headroom(skb), gfp_mask); 3080 } 3081 3082 3083 static inline struct sk_buff *pskb_copy_for_clone(struct sk_buff *skb, 3084 gfp_t gfp_mask) 3085 { 3086 return __pskb_copy_fclone(skb, skb_headroom(skb), gfp_mask, true); 3087 } 3088 3089 3090 /** 3091 * skb_clone_writable - is the header of a clone writable 3092 * @skb: buffer to check 3093 * @len: length up to which to write 3094 * 3095 * Returns true if modifying the header part of the cloned buffer 3096 * does not requires the data to be copied. 3097 */ 3098 static inline int skb_clone_writable(const struct sk_buff *skb, unsigned int len) 3099 { 3100 return !skb_header_cloned(skb) && 3101 skb_headroom(skb) + len <= skb->hdr_len; 3102 } 3103 3104 static inline int skb_try_make_writable(struct sk_buff *skb, 3105 unsigned int write_len) 3106 { 3107 return skb_cloned(skb) && !skb_clone_writable(skb, write_len) && 3108 pskb_expand_head(skb, 0, 0, GFP_ATOMIC); 3109 } 3110 3111 static inline int __skb_cow(struct sk_buff *skb, unsigned int headroom, 3112 int cloned) 3113 { 3114 int delta = 0; 3115 3116 if (headroom > skb_headroom(skb)) 3117 delta = headroom - skb_headroom(skb); 3118 3119 if (delta || cloned) 3120 return pskb_expand_head(skb, ALIGN(delta, NET_SKB_PAD), 0, 3121 GFP_ATOMIC); 3122 return 0; 3123 } 3124 3125 /** 3126 * skb_cow - copy header of skb when it is required 3127 * @skb: buffer to cow 3128 * @headroom: needed headroom 3129 * 3130 * If the skb passed lacks sufficient headroom or its data part 3131 * is shared, data is reallocated. If reallocation fails, an error 3132 * is returned and original skb is not changed. 3133 * 3134 * The result is skb with writable area skb->head...skb->tail 3135 * and at least @headroom of space at head. 3136 */ 3137 static inline int skb_cow(struct sk_buff *skb, unsigned int headroom) 3138 { 3139 return __skb_cow(skb, headroom, skb_cloned(skb)); 3140 } 3141 3142 /** 3143 * skb_cow_head - skb_cow but only making the head writable 3144 * @skb: buffer to cow 3145 * @headroom: needed headroom 3146 * 3147 * This function is identical to skb_cow except that we replace the 3148 * skb_cloned check by skb_header_cloned. It should be used when 3149 * you only need to push on some header and do not need to modify 3150 * the data. 3151 */ 3152 static inline int skb_cow_head(struct sk_buff *skb, unsigned int headroom) 3153 { 3154 return __skb_cow(skb, headroom, skb_header_cloned(skb)); 3155 } 3156 3157 /** 3158 * skb_padto - pad an skbuff up to a minimal size 3159 * @skb: buffer to pad 3160 * @len: minimal length 3161 * 3162 * Pads up a buffer to ensure the trailing bytes exist and are 3163 * blanked. If the buffer already contains sufficient data it 3164 * is untouched. Otherwise it is extended. Returns zero on 3165 * success. The skb is freed on error. 3166 */ 3167 static inline int skb_padto(struct sk_buff *skb, unsigned int len) 3168 { 3169 unsigned int size = skb->len; 3170 if (likely(size >= len)) 3171 return 0; 3172 return skb_pad(skb, len - size); 3173 } 3174 3175 /** 3176 * __skb_put_padto - increase size and pad an skbuff up to a minimal size 3177 * @skb: buffer to pad 3178 * @len: minimal length 3179 * @free_on_error: free buffer on error 3180 * 3181 * Pads up a buffer to ensure the trailing bytes exist and are 3182 * blanked. If the buffer already contains sufficient data it 3183 * is untouched. Otherwise it is extended. Returns zero on 3184 * success. The skb is freed on error if @free_on_error is true. 3185 */ 3186 static inline int __skb_put_padto(struct sk_buff *skb, unsigned int len, 3187 bool free_on_error) 3188 { 3189 unsigned int size = skb->len; 3190 3191 if (unlikely(size < len)) { 3192 len -= size; 3193 if (__skb_pad(skb, len, free_on_error)) 3194 return -ENOMEM; 3195 __skb_put(skb, len); 3196 } 3197 return 0; 3198 } 3199 3200 /** 3201 * skb_put_padto - increase size and pad an skbuff up to a minimal size 3202 * @skb: buffer to pad 3203 * @len: minimal length 3204 * 3205 * Pads up a buffer to ensure the trailing bytes exist and are 3206 * blanked. If the buffer already contains sufficient data it 3207 * is untouched. Otherwise it is extended. Returns zero on 3208 * success. The skb is freed on error. 3209 */ 3210 static inline int skb_put_padto(struct sk_buff *skb, unsigned int len) 3211 { 3212 return __skb_put_padto(skb, len, true); 3213 } 3214 3215 static inline int skb_add_data(struct sk_buff *skb, 3216 struct iov_iter *from, int copy) 3217 { 3218 const int off = skb->len; 3219 3220 if (skb->ip_summed == CHECKSUM_NONE) { 3221 __wsum csum = 0; 3222 if (csum_and_copy_from_iter_full(skb_put(skb, copy), copy, 3223 &csum, from)) { 3224 skb->csum = csum_block_add(skb->csum, csum, off); 3225 return 0; 3226 } 3227 } else if (copy_from_iter_full(skb_put(skb, copy), copy, from)) 3228 return 0; 3229 3230 __skb_trim(skb, off); 3231 return -EFAULT; 3232 } 3233 3234 static inline bool skb_can_coalesce(struct sk_buff *skb, int i, 3235 const struct page *page, int off) 3236 { 3237 if (skb_zcopy(skb)) 3238 return false; 3239 if (i) { 3240 const skb_frag_t *frag = &skb_shinfo(skb)->frags[i - 1]; 3241 3242 return page == skb_frag_page(frag) && 3243 off == skb_frag_off(frag) + skb_frag_size(frag); 3244 } 3245 return false; 3246 } 3247 3248 static inline int __skb_linearize(struct sk_buff *skb) 3249 { 3250 return __pskb_pull_tail(skb, skb->data_len) ? 0 : -ENOMEM; 3251 } 3252 3253 /** 3254 * skb_linearize - convert paged skb to linear one 3255 * @skb: buffer to linarize 3256 * 3257 * If there is no free memory -ENOMEM is returned, otherwise zero 3258 * is returned and the old skb data released. 3259 */ 3260 static inline int skb_linearize(struct sk_buff *skb) 3261 { 3262 return skb_is_nonlinear(skb) ? __skb_linearize(skb) : 0; 3263 } 3264 3265 /** 3266 * skb_has_shared_frag - can any frag be overwritten 3267 * @skb: buffer to test 3268 * 3269 * Return true if the skb has at least one frag that might be modified 3270 * by an external entity (as in vmsplice()/sendfile()) 3271 */ 3272 static inline bool skb_has_shared_frag(const struct sk_buff *skb) 3273 { 3274 return skb_is_nonlinear(skb) && 3275 skb_shinfo(skb)->tx_flags & SKBTX_SHARED_FRAG; 3276 } 3277 3278 /** 3279 * skb_linearize_cow - make sure skb is linear and writable 3280 * @skb: buffer to process 3281 * 3282 * If there is no free memory -ENOMEM is returned, otherwise zero 3283 * is returned and the old skb data released. 3284 */ 3285 static inline int skb_linearize_cow(struct sk_buff *skb) 3286 { 3287 return skb_is_nonlinear(skb) || skb_cloned(skb) ? 3288 __skb_linearize(skb) : 0; 3289 } 3290 3291 static __always_inline void 3292 __skb_postpull_rcsum(struct sk_buff *skb, const void *start, unsigned int len, 3293 unsigned int off) 3294 { 3295 if (skb->ip_summed == CHECKSUM_COMPLETE) 3296 skb->csum = csum_block_sub(skb->csum, 3297 csum_partial(start, len, 0), off); 3298 else if (skb->ip_summed == CHECKSUM_PARTIAL && 3299 skb_checksum_start_offset(skb) < 0) 3300 skb->ip_summed = CHECKSUM_NONE; 3301 } 3302 3303 /** 3304 * skb_postpull_rcsum - update checksum for received skb after pull 3305 * @skb: buffer to update 3306 * @start: start of data before pull 3307 * @len: length of data pulled 3308 * 3309 * After doing a pull on a received packet, you need to call this to 3310 * update the CHECKSUM_COMPLETE checksum, or set ip_summed to 3311 * CHECKSUM_NONE so that it can be recomputed from scratch. 3312 */ 3313 static inline void skb_postpull_rcsum(struct sk_buff *skb, 3314 const void *start, unsigned int len) 3315 { 3316 __skb_postpull_rcsum(skb, start, len, 0); 3317 } 3318 3319 static __always_inline void 3320 __skb_postpush_rcsum(struct sk_buff *skb, const void *start, unsigned int len, 3321 unsigned int off) 3322 { 3323 if (skb->ip_summed == CHECKSUM_COMPLETE) 3324 skb->csum = csum_block_add(skb->csum, 3325 csum_partial(start, len, 0), off); 3326 } 3327 3328 /** 3329 * skb_postpush_rcsum - update checksum for received skb after push 3330 * @skb: buffer to update 3331 * @start: start of data after push 3332 * @len: length of data pushed 3333 * 3334 * After doing a push on a received packet, you need to call this to 3335 * update the CHECKSUM_COMPLETE checksum. 3336 */ 3337 static inline void skb_postpush_rcsum(struct sk_buff *skb, 3338 const void *start, unsigned int len) 3339 { 3340 __skb_postpush_rcsum(skb, start, len, 0); 3341 } 3342 3343 void *skb_pull_rcsum(struct sk_buff *skb, unsigned int len); 3344 3345 /** 3346 * skb_push_rcsum - push skb and update receive checksum 3347 * @skb: buffer to update 3348 * @len: length of data pulled 3349 * 3350 * This function performs an skb_push on the packet and updates 3351 * the CHECKSUM_COMPLETE checksum. It should be used on 3352 * receive path processing instead of skb_push unless you know 3353 * that the checksum difference is zero (e.g., a valid IP header) 3354 * or you are setting ip_summed to CHECKSUM_NONE. 3355 */ 3356 static inline void *skb_push_rcsum(struct sk_buff *skb, unsigned int len) 3357 { 3358 skb_push(skb, len); 3359 skb_postpush_rcsum(skb, skb->data, len); 3360 return skb->data; 3361 } 3362 3363 int pskb_trim_rcsum_slow(struct sk_buff *skb, unsigned int len); 3364 /** 3365 * pskb_trim_rcsum - trim received skb and update checksum 3366 * @skb: buffer to trim 3367 * @len: new length 3368 * 3369 * This is exactly the same as pskb_trim except that it ensures the 3370 * checksum of received packets are still valid after the operation. 3371 * It can change skb pointers. 3372 */ 3373 3374 static inline int pskb_trim_rcsum(struct sk_buff *skb, unsigned int len) 3375 { 3376 if (likely(len >= skb->len)) 3377 return 0; 3378 return pskb_trim_rcsum_slow(skb, len); 3379 } 3380 3381 static inline int __skb_trim_rcsum(struct sk_buff *skb, unsigned int len) 3382 { 3383 if (skb->ip_summed == CHECKSUM_COMPLETE) 3384 skb->ip_summed = CHECKSUM_NONE; 3385 __skb_trim(skb, len); 3386 return 0; 3387 } 3388 3389 static inline int __skb_grow_rcsum(struct sk_buff *skb, unsigned int len) 3390 { 3391 if (skb->ip_summed == CHECKSUM_COMPLETE) 3392 skb->ip_summed = CHECKSUM_NONE; 3393 return __skb_grow(skb, len); 3394 } 3395 3396 #define rb_to_skb(rb) rb_entry_safe(rb, struct sk_buff, rbnode) 3397 #define skb_rb_first(root) rb_to_skb(rb_first(root)) 3398 #define skb_rb_last(root) rb_to_skb(rb_last(root)) 3399 #define skb_rb_next(skb) rb_to_skb(rb_next(&(skb)->rbnode)) 3400 #define skb_rb_prev(skb) rb_to_skb(rb_prev(&(skb)->rbnode)) 3401 3402 #define skb_queue_walk(queue, skb) \ 3403 for (skb = (queue)->next; \ 3404 skb != (struct sk_buff *)(queue); \ 3405 skb = skb->next) 3406 3407 #define skb_queue_walk_safe(queue, skb, tmp) \ 3408 for (skb = (queue)->next, tmp = skb->next; \ 3409 skb != (struct sk_buff *)(queue); \ 3410 skb = tmp, tmp = skb->next) 3411 3412 #define skb_queue_walk_from(queue, skb) \ 3413 for (; skb != (struct sk_buff *)(queue); \ 3414 skb = skb->next) 3415 3416 #define skb_rbtree_walk(skb, root) \ 3417 for (skb = skb_rb_first(root); skb != NULL; \ 3418 skb = skb_rb_next(skb)) 3419 3420 #define skb_rbtree_walk_from(skb) \ 3421 for (; skb != NULL; \ 3422 skb = skb_rb_next(skb)) 3423 3424 #define skb_rbtree_walk_from_safe(skb, tmp) \ 3425 for (; tmp = skb ? skb_rb_next(skb) : NULL, (skb != NULL); \ 3426 skb = tmp) 3427 3428 #define skb_queue_walk_from_safe(queue, skb, tmp) \ 3429 for (tmp = skb->next; \ 3430 skb != (struct sk_buff *)(queue); \ 3431 skb = tmp, tmp = skb->next) 3432 3433 #define skb_queue_reverse_walk(queue, skb) \ 3434 for (skb = (queue)->prev; \ 3435 skb != (struct sk_buff *)(queue); \ 3436 skb = skb->prev) 3437 3438 #define skb_queue_reverse_walk_safe(queue, skb, tmp) \ 3439 for (skb = (queue)->prev, tmp = skb->prev; \ 3440 skb != (struct sk_buff *)(queue); \ 3441 skb = tmp, tmp = skb->prev) 3442 3443 #define skb_queue_reverse_walk_from_safe(queue, skb, tmp) \ 3444 for (tmp = skb->prev; \ 3445 skb != (struct sk_buff *)(queue); \ 3446 skb = tmp, tmp = skb->prev) 3447 3448 static inline bool skb_has_frag_list(const struct sk_buff *skb) 3449 { 3450 return skb_shinfo(skb)->frag_list != NULL; 3451 } 3452 3453 static inline void skb_frag_list_init(struct sk_buff *skb) 3454 { 3455 skb_shinfo(skb)->frag_list = NULL; 3456 } 3457 3458 #define skb_walk_frags(skb, iter) \ 3459 for (iter = skb_shinfo(skb)->frag_list; iter; iter = iter->next) 3460 3461 3462 int __skb_wait_for_more_packets(struct sock *sk, int *err, long *timeo_p, 3463 const struct sk_buff *skb); 3464 struct sk_buff *__skb_try_recv_from_queue(struct sock *sk, 3465 struct sk_buff_head *queue, 3466 unsigned int flags, 3467 void (*destructor)(struct sock *sk, 3468 struct sk_buff *skb), 3469 int *off, int *err, 3470 struct sk_buff **last); 3471 struct sk_buff *__skb_try_recv_datagram(struct sock *sk, unsigned flags, 3472 void (*destructor)(struct sock *sk, 3473 struct sk_buff *skb), 3474 int *off, int *err, 3475 struct sk_buff **last); 3476 struct sk_buff *__skb_recv_datagram(struct sock *sk, unsigned flags, 3477 void (*destructor)(struct sock *sk, 3478 struct sk_buff *skb), 3479 int *off, int *err); 3480 struct sk_buff *skb_recv_datagram(struct sock *sk, unsigned flags, int noblock, 3481 int *err); 3482 __poll_t datagram_poll(struct file *file, struct socket *sock, 3483 struct poll_table_struct *wait); 3484 int skb_copy_datagram_iter(const struct sk_buff *from, int offset, 3485 struct iov_iter *to, int size); 3486 static inline int skb_copy_datagram_msg(const struct sk_buff *from, int offset, 3487 struct msghdr *msg, int size) 3488 { 3489 return skb_copy_datagram_iter(from, offset, &msg->msg_iter, size); 3490 } 3491 int skb_copy_and_csum_datagram_msg(struct sk_buff *skb, int hlen, 3492 struct msghdr *msg); 3493 int skb_copy_and_hash_datagram_iter(const struct sk_buff *skb, int offset, 3494 struct iov_iter *to, int len, 3495 struct ahash_request *hash); 3496 int skb_copy_datagram_from_iter(struct sk_buff *skb, int offset, 3497 struct iov_iter *from, int len); 3498 int zerocopy_sg_from_iter(struct sk_buff *skb, struct iov_iter *frm); 3499 void skb_free_datagram(struct sock *sk, struct sk_buff *skb); 3500 void __skb_free_datagram_locked(struct sock *sk, struct sk_buff *skb, int len); 3501 static inline void skb_free_datagram_locked(struct sock *sk, 3502 struct sk_buff *skb) 3503 { 3504 __skb_free_datagram_locked(sk, skb, 0); 3505 } 3506 int skb_kill_datagram(struct sock *sk, struct sk_buff *skb, unsigned int flags); 3507 int skb_copy_bits(const struct sk_buff *skb, int offset, void *to, int len); 3508 int skb_store_bits(struct sk_buff *skb, int offset, const void *from, int len); 3509 __wsum skb_copy_and_csum_bits(const struct sk_buff *skb, int offset, u8 *to, 3510 int len, __wsum csum); 3511 int skb_splice_bits(struct sk_buff *skb, struct sock *sk, unsigned int offset, 3512 struct pipe_inode_info *pipe, unsigned int len, 3513 unsigned int flags); 3514 int skb_send_sock_locked(struct sock *sk, struct sk_buff *skb, int offset, 3515 int len); 3516 void skb_copy_and_csum_dev(const struct sk_buff *skb, u8 *to); 3517 unsigned int skb_zerocopy_headlen(const struct sk_buff *from); 3518 int skb_zerocopy(struct sk_buff *to, struct sk_buff *from, 3519 int len, int hlen); 3520 void skb_split(struct sk_buff *skb, struct sk_buff *skb1, const u32 len); 3521 int skb_shift(struct sk_buff *tgt, struct sk_buff *skb, int shiftlen); 3522 void skb_scrub_packet(struct sk_buff *skb, bool xnet); 3523 bool skb_gso_validate_network_len(const struct sk_buff *skb, unsigned int mtu); 3524 bool skb_gso_validate_mac_len(const struct sk_buff *skb, unsigned int len); 3525 struct sk_buff *skb_segment(struct sk_buff *skb, netdev_features_t features); 3526 struct sk_buff *skb_vlan_untag(struct sk_buff *skb); 3527 int skb_ensure_writable(struct sk_buff *skb, int write_len); 3528 int __skb_vlan_pop(struct sk_buff *skb, u16 *vlan_tci); 3529 int skb_vlan_pop(struct sk_buff *skb); 3530 int skb_vlan_push(struct sk_buff *skb, __be16 vlan_proto, u16 vlan_tci); 3531 int skb_mpls_push(struct sk_buff *skb, __be32 mpls_lse, __be16 mpls_proto, 3532 int mac_len, bool ethernet); 3533 int skb_mpls_pop(struct sk_buff *skb, __be16 next_proto, int mac_len, 3534 bool ethernet); 3535 int skb_mpls_update_lse(struct sk_buff *skb, __be32 mpls_lse); 3536 int skb_mpls_dec_ttl(struct sk_buff *skb); 3537 struct sk_buff *pskb_extract(struct sk_buff *skb, int off, int to_copy, 3538 gfp_t gfp); 3539 3540 static inline int memcpy_from_msg(void *data, struct msghdr *msg, int len) 3541 { 3542 return copy_from_iter_full(data, len, &msg->msg_iter) ? 0 : -EFAULT; 3543 } 3544 3545 static inline int memcpy_to_msg(struct msghdr *msg, void *data, int len) 3546 { 3547 return copy_to_iter(data, len, &msg->msg_iter) == len ? 0 : -EFAULT; 3548 } 3549 3550 struct skb_checksum_ops { 3551 __wsum (*update)(const void *mem, int len, __wsum wsum); 3552 __wsum (*combine)(__wsum csum, __wsum csum2, int offset, int len); 3553 }; 3554 3555 extern const struct skb_checksum_ops *crc32c_csum_stub __read_mostly; 3556 3557 __wsum __skb_checksum(const struct sk_buff *skb, int offset, int len, 3558 __wsum csum, const struct skb_checksum_ops *ops); 3559 __wsum skb_checksum(const struct sk_buff *skb, int offset, int len, 3560 __wsum csum); 3561 3562 static inline void * __must_check 3563 __skb_header_pointer(const struct sk_buff *skb, int offset, 3564 int len, void *data, int hlen, void *buffer) 3565 { 3566 if (hlen - offset >= len) 3567 return data + offset; 3568 3569 if (!skb || 3570 skb_copy_bits(skb, offset, buffer, len) < 0) 3571 return NULL; 3572 3573 return buffer; 3574 } 3575 3576 static inline void * __must_check 3577 skb_header_pointer(const struct sk_buff *skb, int offset, int len, void *buffer) 3578 { 3579 return __skb_header_pointer(skb, offset, len, skb->data, 3580 skb_headlen(skb), buffer); 3581 } 3582 3583 /** 3584 * skb_needs_linearize - check if we need to linearize a given skb 3585 * depending on the given device features. 3586 * @skb: socket buffer to check 3587 * @features: net device features 3588 * 3589 * Returns true if either: 3590 * 1. skb has frag_list and the device doesn't support FRAGLIST, or 3591 * 2. skb is fragmented and the device does not support SG. 3592 */ 3593 static inline bool skb_needs_linearize(struct sk_buff *skb, 3594 netdev_features_t features) 3595 { 3596 return skb_is_nonlinear(skb) && 3597 ((skb_has_frag_list(skb) && !(features & NETIF_F_FRAGLIST)) || 3598 (skb_shinfo(skb)->nr_frags && !(features & NETIF_F_SG))); 3599 } 3600 3601 static inline void skb_copy_from_linear_data(const struct sk_buff *skb, 3602 void *to, 3603 const unsigned int len) 3604 { 3605 memcpy(to, skb->data, len); 3606 } 3607 3608 static inline void skb_copy_from_linear_data_offset(const struct sk_buff *skb, 3609 const int offset, void *to, 3610 const unsigned int len) 3611 { 3612 memcpy(to, skb->data + offset, len); 3613 } 3614 3615 static inline void skb_copy_to_linear_data(struct sk_buff *skb, 3616 const void *from, 3617 const unsigned int len) 3618 { 3619 memcpy(skb->data, from, len); 3620 } 3621 3622 static inline void skb_copy_to_linear_data_offset(struct sk_buff *skb, 3623 const int offset, 3624 const void *from, 3625 const unsigned int len) 3626 { 3627 memcpy(skb->data + offset, from, len); 3628 } 3629 3630 void skb_init(void); 3631 3632 static inline ktime_t skb_get_ktime(const struct sk_buff *skb) 3633 { 3634 return skb->tstamp; 3635 } 3636 3637 /** 3638 * skb_get_timestamp - get timestamp from a skb 3639 * @skb: skb to get stamp from 3640 * @stamp: pointer to struct __kernel_old_timeval to store stamp in 3641 * 3642 * Timestamps are stored in the skb as offsets to a base timestamp. 3643 * This function converts the offset back to a struct timeval and stores 3644 * it in stamp. 3645 */ 3646 static inline void skb_get_timestamp(const struct sk_buff *skb, 3647 struct __kernel_old_timeval *stamp) 3648 { 3649 *stamp = ns_to_kernel_old_timeval(skb->tstamp); 3650 } 3651 3652 static inline void skb_get_new_timestamp(const struct sk_buff *skb, 3653 struct __kernel_sock_timeval *stamp) 3654 { 3655 struct timespec64 ts = ktime_to_timespec64(skb->tstamp); 3656 3657 stamp->tv_sec = ts.tv_sec; 3658 stamp->tv_usec = ts.tv_nsec / 1000; 3659 } 3660 3661 static inline void skb_get_timestampns(const struct sk_buff *skb, 3662 struct __kernel_old_timespec *stamp) 3663 { 3664 struct timespec64 ts = ktime_to_timespec64(skb->tstamp); 3665 3666 stamp->tv_sec = ts.tv_sec; 3667 stamp->tv_nsec = ts.tv_nsec; 3668 } 3669 3670 static inline void skb_get_new_timestampns(const struct sk_buff *skb, 3671 struct __kernel_timespec *stamp) 3672 { 3673 struct timespec64 ts = ktime_to_timespec64(skb->tstamp); 3674 3675 stamp->tv_sec = ts.tv_sec; 3676 stamp->tv_nsec = ts.tv_nsec; 3677 } 3678 3679 static inline void __net_timestamp(struct sk_buff *skb) 3680 { 3681 skb->tstamp = ktime_get_real(); 3682 } 3683 3684 static inline ktime_t net_timedelta(ktime_t t) 3685 { 3686 return ktime_sub(ktime_get_real(), t); 3687 } 3688 3689 static inline ktime_t net_invalid_timestamp(void) 3690 { 3691 return 0; 3692 } 3693 3694 static inline u8 skb_metadata_len(const struct sk_buff *skb) 3695 { 3696 return skb_shinfo(skb)->meta_len; 3697 } 3698 3699 static inline void *skb_metadata_end(const struct sk_buff *skb) 3700 { 3701 return skb_mac_header(skb); 3702 } 3703 3704 static inline bool __skb_metadata_differs(const struct sk_buff *skb_a, 3705 const struct sk_buff *skb_b, 3706 u8 meta_len) 3707 { 3708 const void *a = skb_metadata_end(skb_a); 3709 const void *b = skb_metadata_end(skb_b); 3710 /* Using more efficient varaiant than plain call to memcmp(). */ 3711 #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64 3712 u64 diffs = 0; 3713 3714 switch (meta_len) { 3715 #define __it(x, op) (x -= sizeof(u##op)) 3716 #define __it_diff(a, b, op) (*(u##op *)__it(a, op)) ^ (*(u##op *)__it(b, op)) 3717 case 32: diffs |= __it_diff(a, b, 64); 3718 /* fall through */ 3719 case 24: diffs |= __it_diff(a, b, 64); 3720 /* fall through */ 3721 case 16: diffs |= __it_diff(a, b, 64); 3722 /* fall through */ 3723 case 8: diffs |= __it_diff(a, b, 64); 3724 break; 3725 case 28: diffs |= __it_diff(a, b, 64); 3726 /* fall through */ 3727 case 20: diffs |= __it_diff(a, b, 64); 3728 /* fall through */ 3729 case 12: diffs |= __it_diff(a, b, 64); 3730 /* fall through */ 3731 case 4: diffs |= __it_diff(a, b, 32); 3732 break; 3733 } 3734 return diffs; 3735 #else 3736 return memcmp(a - meta_len, b - meta_len, meta_len); 3737 #endif 3738 } 3739 3740 static inline bool skb_metadata_differs(const struct sk_buff *skb_a, 3741 const struct sk_buff *skb_b) 3742 { 3743 u8 len_a = skb_metadata_len(skb_a); 3744 u8 len_b = skb_metadata_len(skb_b); 3745 3746 if (!(len_a | len_b)) 3747 return false; 3748 3749 return len_a != len_b ? 3750 true : __skb_metadata_differs(skb_a, skb_b, len_a); 3751 } 3752 3753 static inline void skb_metadata_set(struct sk_buff *skb, u8 meta_len) 3754 { 3755 skb_shinfo(skb)->meta_len = meta_len; 3756 } 3757 3758 static inline void skb_metadata_clear(struct sk_buff *skb) 3759 { 3760 skb_metadata_set(skb, 0); 3761 } 3762 3763 struct sk_buff *skb_clone_sk(struct sk_buff *skb); 3764 3765 #ifdef CONFIG_NETWORK_PHY_TIMESTAMPING 3766 3767 void skb_clone_tx_timestamp(struct sk_buff *skb); 3768 bool skb_defer_rx_timestamp(struct sk_buff *skb); 3769 3770 #else /* CONFIG_NETWORK_PHY_TIMESTAMPING */ 3771 3772 static inline void skb_clone_tx_timestamp(struct sk_buff *skb) 3773 { 3774 } 3775 3776 static inline bool skb_defer_rx_timestamp(struct sk_buff *skb) 3777 { 3778 return false; 3779 } 3780 3781 #endif /* !CONFIG_NETWORK_PHY_TIMESTAMPING */ 3782 3783 /** 3784 * skb_complete_tx_timestamp() - deliver cloned skb with tx timestamps 3785 * 3786 * PHY drivers may accept clones of transmitted packets for 3787 * timestamping via their phy_driver.txtstamp method. These drivers 3788 * must call this function to return the skb back to the stack with a 3789 * timestamp. 3790 * 3791 * @skb: clone of the the original outgoing packet 3792 * @hwtstamps: hardware time stamps 3793 * 3794 */ 3795 void skb_complete_tx_timestamp(struct sk_buff *skb, 3796 struct skb_shared_hwtstamps *hwtstamps); 3797 3798 void __skb_tstamp_tx(struct sk_buff *orig_skb, 3799 struct skb_shared_hwtstamps *hwtstamps, 3800 struct sock *sk, int tstype); 3801 3802 /** 3803 * skb_tstamp_tx - queue clone of skb with send time stamps 3804 * @orig_skb: the original outgoing packet 3805 * @hwtstamps: hardware time stamps, may be NULL if not available 3806 * 3807 * If the skb has a socket associated, then this function clones the 3808 * skb (thus sharing the actual data and optional structures), stores 3809 * the optional hardware time stamping information (if non NULL) or 3810 * generates a software time stamp (otherwise), then queues the clone 3811 * to the error queue of the socket. Errors are silently ignored. 3812 */ 3813 void skb_tstamp_tx(struct sk_buff *orig_skb, 3814 struct skb_shared_hwtstamps *hwtstamps); 3815 3816 /** 3817 * skb_tx_timestamp() - Driver hook for transmit timestamping 3818 * 3819 * Ethernet MAC Drivers should call this function in their hard_xmit() 3820 * function immediately before giving the sk_buff to the MAC hardware. 3821 * 3822 * Specifically, one should make absolutely sure that this function is 3823 * called before TX completion of this packet can trigger. Otherwise 3824 * the packet could potentially already be freed. 3825 * 3826 * @skb: A socket buffer. 3827 */ 3828 static inline void skb_tx_timestamp(struct sk_buff *skb) 3829 { 3830 skb_clone_tx_timestamp(skb); 3831 if (skb_shinfo(skb)->tx_flags & SKBTX_SW_TSTAMP) 3832 skb_tstamp_tx(skb, NULL); 3833 } 3834 3835 /** 3836 * skb_complete_wifi_ack - deliver skb with wifi status 3837 * 3838 * @skb: the original outgoing packet 3839 * @acked: ack status 3840 * 3841 */ 3842 void skb_complete_wifi_ack(struct sk_buff *skb, bool acked); 3843 3844 __sum16 __skb_checksum_complete_head(struct sk_buff *skb, int len); 3845 __sum16 __skb_checksum_complete(struct sk_buff *skb); 3846 3847 static inline int skb_csum_unnecessary(const struct sk_buff *skb) 3848 { 3849 return ((skb->ip_summed == CHECKSUM_UNNECESSARY) || 3850 skb->csum_valid || 3851 (skb->ip_summed == CHECKSUM_PARTIAL && 3852 skb_checksum_start_offset(skb) >= 0)); 3853 } 3854 3855 /** 3856 * skb_checksum_complete - Calculate checksum of an entire packet 3857 * @skb: packet to process 3858 * 3859 * This function calculates the checksum over the entire packet plus 3860 * the value of skb->csum. The latter can be used to supply the 3861 * checksum of a pseudo header as used by TCP/UDP. It returns the 3862 * checksum. 3863 * 3864 * For protocols that contain complete checksums such as ICMP/TCP/UDP, 3865 * this function can be used to verify that checksum on received 3866 * packets. In that case the function should return zero if the 3867 * checksum is correct. In particular, this function will return zero 3868 * if skb->ip_summed is CHECKSUM_UNNECESSARY which indicates that the 3869 * hardware has already verified the correctness of the checksum. 3870 */ 3871 static inline __sum16 skb_checksum_complete(struct sk_buff *skb) 3872 { 3873 return skb_csum_unnecessary(skb) ? 3874 0 : __skb_checksum_complete(skb); 3875 } 3876 3877 static inline void __skb_decr_checksum_unnecessary(struct sk_buff *skb) 3878 { 3879 if (skb->ip_summed == CHECKSUM_UNNECESSARY) { 3880 if (skb->csum_level == 0) 3881 skb->ip_summed = CHECKSUM_NONE; 3882 else 3883 skb->csum_level--; 3884 } 3885 } 3886 3887 static inline void __skb_incr_checksum_unnecessary(struct sk_buff *skb) 3888 { 3889 if (skb->ip_summed == CHECKSUM_UNNECESSARY) { 3890 if (skb->csum_level < SKB_MAX_CSUM_LEVEL) 3891 skb->csum_level++; 3892 } else if (skb->ip_summed == CHECKSUM_NONE) { 3893 skb->ip_summed = CHECKSUM_UNNECESSARY; 3894 skb->csum_level = 0; 3895 } 3896 } 3897 3898 /* Check if we need to perform checksum complete validation. 3899 * 3900 * Returns true if checksum complete is needed, false otherwise 3901 * (either checksum is unnecessary or zero checksum is allowed). 3902 */ 3903 static inline bool __skb_checksum_validate_needed(struct sk_buff *skb, 3904 bool zero_okay, 3905 __sum16 check) 3906 { 3907 if (skb_csum_unnecessary(skb) || (zero_okay && !check)) { 3908 skb->csum_valid = 1; 3909 __skb_decr_checksum_unnecessary(skb); 3910 return false; 3911 } 3912 3913 return true; 3914 } 3915 3916 /* For small packets <= CHECKSUM_BREAK perform checksum complete directly 3917 * in checksum_init. 3918 */ 3919 #define CHECKSUM_BREAK 76 3920 3921 /* Unset checksum-complete 3922 * 3923 * Unset checksum complete can be done when packet is being modified 3924 * (uncompressed for instance) and checksum-complete value is 3925 * invalidated. 3926 */ 3927 static inline void skb_checksum_complete_unset(struct sk_buff *skb) 3928 { 3929 if (skb->ip_summed == CHECKSUM_COMPLETE) 3930 skb->ip_summed = CHECKSUM_NONE; 3931 } 3932 3933 /* Validate (init) checksum based on checksum complete. 3934 * 3935 * Return values: 3936 * 0: checksum is validated or try to in skb_checksum_complete. In the latter 3937 * case the ip_summed will not be CHECKSUM_UNNECESSARY and the pseudo 3938 * checksum is stored in skb->csum for use in __skb_checksum_complete 3939 * non-zero: value of invalid checksum 3940 * 3941 */ 3942 static inline __sum16 __skb_checksum_validate_complete(struct sk_buff *skb, 3943 bool complete, 3944 __wsum psum) 3945 { 3946 if (skb->ip_summed == CHECKSUM_COMPLETE) { 3947 if (!csum_fold(csum_add(psum, skb->csum))) { 3948 skb->csum_valid = 1; 3949 return 0; 3950 } 3951 } 3952 3953 skb->csum = psum; 3954 3955 if (complete || skb->len <= CHECKSUM_BREAK) { 3956 __sum16 csum; 3957 3958 csum = __skb_checksum_complete(skb); 3959 skb->csum_valid = !csum; 3960 return csum; 3961 } 3962 3963 return 0; 3964 } 3965 3966 static inline __wsum null_compute_pseudo(struct sk_buff *skb, int proto) 3967 { 3968 return 0; 3969 } 3970 3971 /* Perform checksum validate (init). Note that this is a macro since we only 3972 * want to calculate the pseudo header which is an input function if necessary. 3973 * First we try to validate without any computation (checksum unnecessary) and 3974 * then calculate based on checksum complete calling the function to compute 3975 * pseudo header. 3976 * 3977 * Return values: 3978 * 0: checksum is validated or try to in skb_checksum_complete 3979 * non-zero: value of invalid checksum 3980 */ 3981 #define __skb_checksum_validate(skb, proto, complete, \ 3982 zero_okay, check, compute_pseudo) \ 3983 ({ \ 3984 __sum16 __ret = 0; \ 3985 skb->csum_valid = 0; \ 3986 if (__skb_checksum_validate_needed(skb, zero_okay, check)) \ 3987 __ret = __skb_checksum_validate_complete(skb, \ 3988 complete, compute_pseudo(skb, proto)); \ 3989 __ret; \ 3990 }) 3991 3992 #define skb_checksum_init(skb, proto, compute_pseudo) \ 3993 __skb_checksum_validate(skb, proto, false, false, 0, compute_pseudo) 3994 3995 #define skb_checksum_init_zero_check(skb, proto, check, compute_pseudo) \ 3996 __skb_checksum_validate(skb, proto, false, true, check, compute_pseudo) 3997 3998 #define skb_checksum_validate(skb, proto, compute_pseudo) \ 3999 __skb_checksum_validate(skb, proto, true, false, 0, compute_pseudo) 4000 4001 #define skb_checksum_validate_zero_check(skb, proto, check, \ 4002 compute_pseudo) \ 4003 __skb_checksum_validate(skb, proto, true, true, check, compute_pseudo) 4004 4005 #define skb_checksum_simple_validate(skb) \ 4006 __skb_checksum_validate(skb, 0, true, false, 0, null_compute_pseudo) 4007 4008 static inline bool __skb_checksum_convert_check(struct sk_buff *skb) 4009 { 4010 return (skb->ip_summed == CHECKSUM_NONE && skb->csum_valid); 4011 } 4012 4013 static inline void __skb_checksum_convert(struct sk_buff *skb, __wsum pseudo) 4014 { 4015 skb->csum = ~pseudo; 4016 skb->ip_summed = CHECKSUM_COMPLETE; 4017 } 4018 4019 #define skb_checksum_try_convert(skb, proto, compute_pseudo) \ 4020 do { \ 4021 if (__skb_checksum_convert_check(skb)) \ 4022 __skb_checksum_convert(skb, compute_pseudo(skb, proto)); \ 4023 } while (0) 4024 4025 static inline void skb_remcsum_adjust_partial(struct sk_buff *skb, void *ptr, 4026 u16 start, u16 offset) 4027 { 4028 skb->ip_summed = CHECKSUM_PARTIAL; 4029 skb->csum_start = ((unsigned char *)ptr + start) - skb->head; 4030 skb->csum_offset = offset - start; 4031 } 4032 4033 /* Update skbuf and packet to reflect the remote checksum offload operation. 4034 * When called, ptr indicates the starting point for skb->csum when 4035 * ip_summed is CHECKSUM_COMPLETE. If we need create checksum complete 4036 * here, skb_postpull_rcsum is done so skb->csum start is ptr. 4037 */ 4038 static inline void skb_remcsum_process(struct sk_buff *skb, void *ptr, 4039 int start, int offset, bool nopartial) 4040 { 4041 __wsum delta; 4042 4043 if (!nopartial) { 4044 skb_remcsum_adjust_partial(skb, ptr, start, offset); 4045 return; 4046 } 4047 4048 if (unlikely(skb->ip_summed != CHECKSUM_COMPLETE)) { 4049 __skb_checksum_complete(skb); 4050 skb_postpull_rcsum(skb, skb->data, ptr - (void *)skb->data); 4051 } 4052 4053 delta = remcsum_adjust(ptr, skb->csum, start, offset); 4054 4055 /* Adjust skb->csum since we changed the packet */ 4056 skb->csum = csum_add(skb->csum, delta); 4057 } 4058 4059 static inline struct nf_conntrack *skb_nfct(const struct sk_buff *skb) 4060 { 4061 #if IS_ENABLED(CONFIG_NF_CONNTRACK) 4062 return (void *)(skb->_nfct & NFCT_PTRMASK); 4063 #else 4064 return NULL; 4065 #endif 4066 } 4067 4068 static inline unsigned long skb_get_nfct(const struct sk_buff *skb) 4069 { 4070 #if IS_ENABLED(CONFIG_NF_CONNTRACK) 4071 return skb->_nfct; 4072 #else 4073 return 0UL; 4074 #endif 4075 } 4076 4077 static inline void skb_set_nfct(struct sk_buff *skb, unsigned long nfct) 4078 { 4079 #if IS_ENABLED(CONFIG_NF_CONNTRACK) 4080 skb->_nfct = nfct; 4081 #endif 4082 } 4083 4084 #ifdef CONFIG_SKB_EXTENSIONS 4085 enum skb_ext_id { 4086 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER) 4087 SKB_EXT_BRIDGE_NF, 4088 #endif 4089 #ifdef CONFIG_XFRM 4090 SKB_EXT_SEC_PATH, 4091 #endif 4092 #if IS_ENABLED(CONFIG_NET_TC_SKB_EXT) 4093 TC_SKB_EXT, 4094 #endif 4095 SKB_EXT_NUM, /* must be last */ 4096 }; 4097 4098 /** 4099 * struct skb_ext - sk_buff extensions 4100 * @refcnt: 1 on allocation, deallocated on 0 4101 * @offset: offset to add to @data to obtain extension address 4102 * @chunks: size currently allocated, stored in SKB_EXT_ALIGN_SHIFT units 4103 * @data: start of extension data, variable sized 4104 * 4105 * Note: offsets/lengths are stored in chunks of 8 bytes, this allows 4106 * to use 'u8' types while allowing up to 2kb worth of extension data. 4107 */ 4108 struct skb_ext { 4109 refcount_t refcnt; 4110 u8 offset[SKB_EXT_NUM]; /* in chunks of 8 bytes */ 4111 u8 chunks; /* same */ 4112 char data[0] __aligned(8); 4113 }; 4114 4115 void *skb_ext_add(struct sk_buff *skb, enum skb_ext_id id); 4116 void __skb_ext_del(struct sk_buff *skb, enum skb_ext_id id); 4117 void __skb_ext_put(struct skb_ext *ext); 4118 4119 static inline void skb_ext_put(struct sk_buff *skb) 4120 { 4121 if (skb->active_extensions) 4122 __skb_ext_put(skb->extensions); 4123 } 4124 4125 static inline void __skb_ext_copy(struct sk_buff *dst, 4126 const struct sk_buff *src) 4127 { 4128 dst->active_extensions = src->active_extensions; 4129 4130 if (src->active_extensions) { 4131 struct skb_ext *ext = src->extensions; 4132 4133 refcount_inc(&ext->refcnt); 4134 dst->extensions = ext; 4135 } 4136 } 4137 4138 static inline void skb_ext_copy(struct sk_buff *dst, const struct sk_buff *src) 4139 { 4140 skb_ext_put(dst); 4141 __skb_ext_copy(dst, src); 4142 } 4143 4144 static inline bool __skb_ext_exist(const struct skb_ext *ext, enum skb_ext_id i) 4145 { 4146 return !!ext->offset[i]; 4147 } 4148 4149 static inline bool skb_ext_exist(const struct sk_buff *skb, enum skb_ext_id id) 4150 { 4151 return skb->active_extensions & (1 << id); 4152 } 4153 4154 static inline void skb_ext_del(struct sk_buff *skb, enum skb_ext_id id) 4155 { 4156 if (skb_ext_exist(skb, id)) 4157 __skb_ext_del(skb, id); 4158 } 4159 4160 static inline void *skb_ext_find(const struct sk_buff *skb, enum skb_ext_id id) 4161 { 4162 if (skb_ext_exist(skb, id)) { 4163 struct skb_ext *ext = skb->extensions; 4164 4165 return (void *)ext + (ext->offset[id] << 3); 4166 } 4167 4168 return NULL; 4169 } 4170 4171 static inline void skb_ext_reset(struct sk_buff *skb) 4172 { 4173 if (unlikely(skb->active_extensions)) { 4174 __skb_ext_put(skb->extensions); 4175 skb->active_extensions = 0; 4176 } 4177 } 4178 4179 static inline bool skb_has_extensions(struct sk_buff *skb) 4180 { 4181 return unlikely(skb->active_extensions); 4182 } 4183 #else 4184 static inline void skb_ext_put(struct sk_buff *skb) {} 4185 static inline void skb_ext_reset(struct sk_buff *skb) {} 4186 static inline void skb_ext_del(struct sk_buff *skb, int unused) {} 4187 static inline void __skb_ext_copy(struct sk_buff *d, const struct sk_buff *s) {} 4188 static inline void skb_ext_copy(struct sk_buff *dst, const struct sk_buff *s) {} 4189 static inline bool skb_has_extensions(struct sk_buff *skb) { return false; } 4190 #endif /* CONFIG_SKB_EXTENSIONS */ 4191 4192 static inline void nf_reset_ct(struct sk_buff *skb) 4193 { 4194 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE) 4195 nf_conntrack_put(skb_nfct(skb)); 4196 skb->_nfct = 0; 4197 #endif 4198 } 4199 4200 static inline void nf_reset_trace(struct sk_buff *skb) 4201 { 4202 #if IS_ENABLED(CONFIG_NETFILTER_XT_TARGET_TRACE) || defined(CONFIG_NF_TABLES) 4203 skb->nf_trace = 0; 4204 #endif 4205 } 4206 4207 static inline void ipvs_reset(struct sk_buff *skb) 4208 { 4209 #if IS_ENABLED(CONFIG_IP_VS) 4210 skb->ipvs_property = 0; 4211 #endif 4212 } 4213 4214 /* Note: This doesn't put any conntrack info in dst. */ 4215 static inline void __nf_copy(struct sk_buff *dst, const struct sk_buff *src, 4216 bool copy) 4217 { 4218 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE) 4219 dst->_nfct = src->_nfct; 4220 nf_conntrack_get(skb_nfct(src)); 4221 #endif 4222 #if IS_ENABLED(CONFIG_NETFILTER_XT_TARGET_TRACE) || defined(CONFIG_NF_TABLES) 4223 if (copy) 4224 dst->nf_trace = src->nf_trace; 4225 #endif 4226 } 4227 4228 static inline void nf_copy(struct sk_buff *dst, const struct sk_buff *src) 4229 { 4230 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE) 4231 nf_conntrack_put(skb_nfct(dst)); 4232 #endif 4233 __nf_copy(dst, src, true); 4234 } 4235 4236 #ifdef CONFIG_NETWORK_SECMARK 4237 static inline void skb_copy_secmark(struct sk_buff *to, const struct sk_buff *from) 4238 { 4239 to->secmark = from->secmark; 4240 } 4241 4242 static inline void skb_init_secmark(struct sk_buff *skb) 4243 { 4244 skb->secmark = 0; 4245 } 4246 #else 4247 static inline void skb_copy_secmark(struct sk_buff *to, const struct sk_buff *from) 4248 { } 4249 4250 static inline void skb_init_secmark(struct sk_buff *skb) 4251 { } 4252 #endif 4253 4254 static inline int secpath_exists(const struct sk_buff *skb) 4255 { 4256 #ifdef CONFIG_XFRM 4257 return skb_ext_exist(skb, SKB_EXT_SEC_PATH); 4258 #else 4259 return 0; 4260 #endif 4261 } 4262 4263 static inline bool skb_irq_freeable(const struct sk_buff *skb) 4264 { 4265 return !skb->destructor && 4266 !secpath_exists(skb) && 4267 !skb_nfct(skb) && 4268 !skb->_skb_refdst && 4269 !skb_has_frag_list(skb); 4270 } 4271 4272 static inline void skb_set_queue_mapping(struct sk_buff *skb, u16 queue_mapping) 4273 { 4274 skb->queue_mapping = queue_mapping; 4275 } 4276 4277 static inline u16 skb_get_queue_mapping(const struct sk_buff *skb) 4278 { 4279 return skb->queue_mapping; 4280 } 4281 4282 static inline void skb_copy_queue_mapping(struct sk_buff *to, const struct sk_buff *from) 4283 { 4284 to->queue_mapping = from->queue_mapping; 4285 } 4286 4287 static inline void skb_record_rx_queue(struct sk_buff *skb, u16 rx_queue) 4288 { 4289 skb->queue_mapping = rx_queue + 1; 4290 } 4291 4292 static inline u16 skb_get_rx_queue(const struct sk_buff *skb) 4293 { 4294 return skb->queue_mapping - 1; 4295 } 4296 4297 static inline bool skb_rx_queue_recorded(const struct sk_buff *skb) 4298 { 4299 return skb->queue_mapping != 0; 4300 } 4301 4302 static inline void skb_set_dst_pending_confirm(struct sk_buff *skb, u32 val) 4303 { 4304 skb->dst_pending_confirm = val; 4305 } 4306 4307 static inline bool skb_get_dst_pending_confirm(const struct sk_buff *skb) 4308 { 4309 return skb->dst_pending_confirm != 0; 4310 } 4311 4312 static inline struct sec_path *skb_sec_path(const struct sk_buff *skb) 4313 { 4314 #ifdef CONFIG_XFRM 4315 return skb_ext_find(skb, SKB_EXT_SEC_PATH); 4316 #else 4317 return NULL; 4318 #endif 4319 } 4320 4321 /* Keeps track of mac header offset relative to skb->head. 4322 * It is useful for TSO of Tunneling protocol. e.g. GRE. 4323 * For non-tunnel skb it points to skb_mac_header() and for 4324 * tunnel skb it points to outer mac header. 4325 * Keeps track of level of encapsulation of network headers. 4326 */ 4327 struct skb_gso_cb { 4328 union { 4329 int mac_offset; 4330 int data_offset; 4331 }; 4332 int encap_level; 4333 __wsum csum; 4334 __u16 csum_start; 4335 }; 4336 #define SKB_SGO_CB_OFFSET 32 4337 #define SKB_GSO_CB(skb) ((struct skb_gso_cb *)((skb)->cb + SKB_SGO_CB_OFFSET)) 4338 4339 static inline int skb_tnl_header_len(const struct sk_buff *inner_skb) 4340 { 4341 return (skb_mac_header(inner_skb) - inner_skb->head) - 4342 SKB_GSO_CB(inner_skb)->mac_offset; 4343 } 4344 4345 static inline int gso_pskb_expand_head(struct sk_buff *skb, int extra) 4346 { 4347 int new_headroom, headroom; 4348 int ret; 4349 4350 headroom = skb_headroom(skb); 4351 ret = pskb_expand_head(skb, extra, 0, GFP_ATOMIC); 4352 if (ret) 4353 return ret; 4354 4355 new_headroom = skb_headroom(skb); 4356 SKB_GSO_CB(skb)->mac_offset += (new_headroom - headroom); 4357 return 0; 4358 } 4359 4360 static inline void gso_reset_checksum(struct sk_buff *skb, __wsum res) 4361 { 4362 /* Do not update partial checksums if remote checksum is enabled. */ 4363 if (skb->remcsum_offload) 4364 return; 4365 4366 SKB_GSO_CB(skb)->csum = res; 4367 SKB_GSO_CB(skb)->csum_start = skb_checksum_start(skb) - skb->head; 4368 } 4369 4370 /* Compute the checksum for a gso segment. First compute the checksum value 4371 * from the start of transport header to SKB_GSO_CB(skb)->csum_start, and 4372 * then add in skb->csum (checksum from csum_start to end of packet). 4373 * skb->csum and csum_start are then updated to reflect the checksum of the 4374 * resultant packet starting from the transport header-- the resultant checksum 4375 * is in the res argument (i.e. normally zero or ~ of checksum of a pseudo 4376 * header. 4377 */ 4378 static inline __sum16 gso_make_checksum(struct sk_buff *skb, __wsum res) 4379 { 4380 unsigned char *csum_start = skb_transport_header(skb); 4381 int plen = (skb->head + SKB_GSO_CB(skb)->csum_start) - csum_start; 4382 __wsum partial = SKB_GSO_CB(skb)->csum; 4383 4384 SKB_GSO_CB(skb)->csum = res; 4385 SKB_GSO_CB(skb)->csum_start = csum_start - skb->head; 4386 4387 return csum_fold(csum_partial(csum_start, plen, partial)); 4388 } 4389 4390 static inline bool skb_is_gso(const struct sk_buff *skb) 4391 { 4392 return skb_shinfo(skb)->gso_size; 4393 } 4394 4395 /* Note: Should be called only if skb_is_gso(skb) is true */ 4396 static inline bool skb_is_gso_v6(const struct sk_buff *skb) 4397 { 4398 return skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6; 4399 } 4400 4401 /* Note: Should be called only if skb_is_gso(skb) is true */ 4402 static inline bool skb_is_gso_sctp(const struct sk_buff *skb) 4403 { 4404 return skb_shinfo(skb)->gso_type & SKB_GSO_SCTP; 4405 } 4406 4407 /* Note: Should be called only if skb_is_gso(skb) is true */ 4408 static inline bool skb_is_gso_tcp(const struct sk_buff *skb) 4409 { 4410 return skb_shinfo(skb)->gso_type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6); 4411 } 4412 4413 static inline void skb_gso_reset(struct sk_buff *skb) 4414 { 4415 skb_shinfo(skb)->gso_size = 0; 4416 skb_shinfo(skb)->gso_segs = 0; 4417 skb_shinfo(skb)->gso_type = 0; 4418 } 4419 4420 static inline void skb_increase_gso_size(struct skb_shared_info *shinfo, 4421 u16 increment) 4422 { 4423 if (WARN_ON_ONCE(shinfo->gso_size == GSO_BY_FRAGS)) 4424 return; 4425 shinfo->gso_size += increment; 4426 } 4427 4428 static inline void skb_decrease_gso_size(struct skb_shared_info *shinfo, 4429 u16 decrement) 4430 { 4431 if (WARN_ON_ONCE(shinfo->gso_size == GSO_BY_FRAGS)) 4432 return; 4433 shinfo->gso_size -= decrement; 4434 } 4435 4436 void __skb_warn_lro_forwarding(const struct sk_buff *skb); 4437 4438 static inline bool skb_warn_if_lro(const struct sk_buff *skb) 4439 { 4440 /* LRO sets gso_size but not gso_type, whereas if GSO is really 4441 * wanted then gso_type will be set. */ 4442 const struct skb_shared_info *shinfo = skb_shinfo(skb); 4443 4444 if (skb_is_nonlinear(skb) && shinfo->gso_size != 0 && 4445 unlikely(shinfo->gso_type == 0)) { 4446 __skb_warn_lro_forwarding(skb); 4447 return true; 4448 } 4449 return false; 4450 } 4451 4452 static inline void skb_forward_csum(struct sk_buff *skb) 4453 { 4454 /* Unfortunately we don't support this one. Any brave souls? */ 4455 if (skb->ip_summed == CHECKSUM_COMPLETE) 4456 skb->ip_summed = CHECKSUM_NONE; 4457 } 4458 4459 /** 4460 * skb_checksum_none_assert - make sure skb ip_summed is CHECKSUM_NONE 4461 * @skb: skb to check 4462 * 4463 * fresh skbs have their ip_summed set to CHECKSUM_NONE. 4464 * Instead of forcing ip_summed to CHECKSUM_NONE, we can 4465 * use this helper, to document places where we make this assertion. 4466 */ 4467 static inline void skb_checksum_none_assert(const struct sk_buff *skb) 4468 { 4469 #ifdef DEBUG 4470 BUG_ON(skb->ip_summed != CHECKSUM_NONE); 4471 #endif 4472 } 4473 4474 bool skb_partial_csum_set(struct sk_buff *skb, u16 start, u16 off); 4475 4476 int skb_checksum_setup(struct sk_buff *skb, bool recalculate); 4477 struct sk_buff *skb_checksum_trimmed(struct sk_buff *skb, 4478 unsigned int transport_len, 4479 __sum16(*skb_chkf)(struct sk_buff *skb)); 4480 4481 /** 4482 * skb_head_is_locked - Determine if the skb->head is locked down 4483 * @skb: skb to check 4484 * 4485 * The head on skbs build around a head frag can be removed if they are 4486 * not cloned. This function returns true if the skb head is locked down 4487 * due to either being allocated via kmalloc, or by being a clone with 4488 * multiple references to the head. 4489 */ 4490 static inline bool skb_head_is_locked(const struct sk_buff *skb) 4491 { 4492 return !skb->head_frag || skb_cloned(skb); 4493 } 4494 4495 /* Local Checksum Offload. 4496 * Compute outer checksum based on the assumption that the 4497 * inner checksum will be offloaded later. 4498 * See Documentation/networking/checksum-offloads.rst for 4499 * explanation of how this works. 4500 * Fill in outer checksum adjustment (e.g. with sum of outer 4501 * pseudo-header) before calling. 4502 * Also ensure that inner checksum is in linear data area. 4503 */ 4504 static inline __wsum lco_csum(struct sk_buff *skb) 4505 { 4506 unsigned char *csum_start = skb_checksum_start(skb); 4507 unsigned char *l4_hdr = skb_transport_header(skb); 4508 __wsum partial; 4509 4510 /* Start with complement of inner checksum adjustment */ 4511 partial = ~csum_unfold(*(__force __sum16 *)(csum_start + 4512 skb->csum_offset)); 4513 4514 /* Add in checksum of our headers (incl. outer checksum 4515 * adjustment filled in by caller) and return result. 4516 */ 4517 return csum_partial(l4_hdr, csum_start - l4_hdr, partial); 4518 } 4519 4520 #endif /* __KERNEL__ */ 4521 #endif /* _LINUX_SKBUFF_H */ 4522