1 /* 2 * Definitions for the 'struct sk_buff' memory handlers. 3 * 4 * Authors: 5 * Alan Cox, <[email protected]> 6 * Florian La Roche, <[email protected]> 7 * 8 * This program is free software; you can redistribute it and/or 9 * modify it under the terms of the GNU General Public License 10 * as published by the Free Software Foundation; either version 11 * 2 of the License, or (at your option) any later version. 12 */ 13 14 #ifndef _LINUX_SKBUFF_H 15 #define _LINUX_SKBUFF_H 16 17 #include <linux/kernel.h> 18 #include <linux/kmemcheck.h> 19 #include <linux/compiler.h> 20 #include <linux/time.h> 21 #include <linux/bug.h> 22 #include <linux/cache.h> 23 24 #include <linux/atomic.h> 25 #include <asm/types.h> 26 #include <linux/spinlock.h> 27 #include <linux/net.h> 28 #include <linux/textsearch.h> 29 #include <net/checksum.h> 30 #include <linux/rcupdate.h> 31 #include <linux/dmaengine.h> 32 #include <linux/hrtimer.h> 33 #include <linux/dma-mapping.h> 34 #include <linux/netdev_features.h> 35 36 /* Don't change this without changing skb_csum_unnecessary! */ 37 #define CHECKSUM_NONE 0 38 #define CHECKSUM_UNNECESSARY 1 39 #define CHECKSUM_COMPLETE 2 40 #define CHECKSUM_PARTIAL 3 41 42 #define SKB_DATA_ALIGN(X) (((X) + (SMP_CACHE_BYTES - 1)) & \ 43 ~(SMP_CACHE_BYTES - 1)) 44 #define SKB_WITH_OVERHEAD(X) \ 45 ((X) - SKB_DATA_ALIGN(sizeof(struct skb_shared_info))) 46 #define SKB_MAX_ORDER(X, ORDER) \ 47 SKB_WITH_OVERHEAD((PAGE_SIZE << (ORDER)) - (X)) 48 #define SKB_MAX_HEAD(X) (SKB_MAX_ORDER((X), 0)) 49 #define SKB_MAX_ALLOC (SKB_MAX_ORDER(0, 2)) 50 51 /* return minimum truesize of one skb containing X bytes of data */ 52 #define SKB_TRUESIZE(X) ((X) + \ 53 SKB_DATA_ALIGN(sizeof(struct sk_buff)) + \ 54 SKB_DATA_ALIGN(sizeof(struct skb_shared_info))) 55 56 /* A. Checksumming of received packets by device. 57 * 58 * NONE: device failed to checksum this packet. 59 * skb->csum is undefined. 60 * 61 * UNNECESSARY: device parsed packet and wouldbe verified checksum. 62 * skb->csum is undefined. 63 * It is bad option, but, unfortunately, many of vendors do this. 64 * Apparently with secret goal to sell you new device, when you 65 * will add new protocol to your host. F.e. IPv6. 8) 66 * 67 * COMPLETE: the most generic way. Device supplied checksum of _all_ 68 * the packet as seen by netif_rx in skb->csum. 69 * NOTE: Even if device supports only some protocols, but 70 * is able to produce some skb->csum, it MUST use COMPLETE, 71 * not UNNECESSARY. 72 * 73 * PARTIAL: identical to the case for output below. This may occur 74 * on a packet received directly from another Linux OS, e.g., 75 * a virtualised Linux kernel on the same host. The packet can 76 * be treated in the same way as UNNECESSARY except that on 77 * output (i.e., forwarding) the checksum must be filled in 78 * by the OS or the hardware. 79 * 80 * B. Checksumming on output. 81 * 82 * NONE: skb is checksummed by protocol or csum is not required. 83 * 84 * PARTIAL: device is required to csum packet as seen by hard_start_xmit 85 * from skb->csum_start to the end and to record the checksum 86 * at skb->csum_start + skb->csum_offset. 87 * 88 * Device must show its capabilities in dev->features, set 89 * at device setup time. 90 * NETIF_F_HW_CSUM - it is clever device, it is able to checksum 91 * everything. 92 * NETIF_F_IP_CSUM - device is dumb. It is able to csum only 93 * TCP/UDP over IPv4. Sigh. Vendors like this 94 * way by an unknown reason. Though, see comment above 95 * about CHECKSUM_UNNECESSARY. 8) 96 * NETIF_F_IPV6_CSUM about as dumb as the last one but does IPv6 instead. 97 * 98 * UNNECESSARY: device will do per protocol specific csum. Protocol drivers 99 * that do not want net to perform the checksum calculation should use 100 * this flag in their outgoing skbs. 101 * NETIF_F_FCOE_CRC this indicates the device can do FCoE FC CRC 102 * offload. Correspondingly, the FCoE protocol driver 103 * stack should use CHECKSUM_UNNECESSARY. 104 * 105 * Any questions? No questions, good. --ANK 106 */ 107 108 struct net_device; 109 struct scatterlist; 110 struct pipe_inode_info; 111 112 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE) 113 struct nf_conntrack { 114 atomic_t use; 115 }; 116 #endif 117 118 #ifdef CONFIG_BRIDGE_NETFILTER 119 struct nf_bridge_info { 120 atomic_t use; 121 unsigned int mask; 122 struct net_device *physindev; 123 struct net_device *physoutdev; 124 unsigned long data[32 / sizeof(unsigned long)]; 125 }; 126 #endif 127 128 struct sk_buff_head { 129 /* These two members must be first. */ 130 struct sk_buff *next; 131 struct sk_buff *prev; 132 133 __u32 qlen; 134 spinlock_t lock; 135 }; 136 137 struct sk_buff; 138 139 /* To allow 64K frame to be packed as single skb without frag_list we 140 * require 64K/PAGE_SIZE pages plus 1 additional page to allow for 141 * buffers which do not start on a page boundary. 142 * 143 * Since GRO uses frags we allocate at least 16 regardless of page 144 * size. 145 */ 146 #if (65536/PAGE_SIZE + 1) < 16 147 #define MAX_SKB_FRAGS 16UL 148 #else 149 #define MAX_SKB_FRAGS (65536/PAGE_SIZE + 1) 150 #endif 151 152 typedef struct skb_frag_struct skb_frag_t; 153 154 struct skb_frag_struct { 155 struct { 156 struct page *p; 157 } page; 158 #if (BITS_PER_LONG > 32) || (PAGE_SIZE >= 65536) 159 __u32 page_offset; 160 __u32 size; 161 #else 162 __u16 page_offset; 163 __u16 size; 164 #endif 165 }; 166 167 static inline unsigned int skb_frag_size(const skb_frag_t *frag) 168 { 169 return frag->size; 170 } 171 172 static inline void skb_frag_size_set(skb_frag_t *frag, unsigned int size) 173 { 174 frag->size = size; 175 } 176 177 static inline void skb_frag_size_add(skb_frag_t *frag, int delta) 178 { 179 frag->size += delta; 180 } 181 182 static inline void skb_frag_size_sub(skb_frag_t *frag, int delta) 183 { 184 frag->size -= delta; 185 } 186 187 #define HAVE_HW_TIME_STAMP 188 189 /** 190 * struct skb_shared_hwtstamps - hardware time stamps 191 * @hwtstamp: hardware time stamp transformed into duration 192 * since arbitrary point in time 193 * @syststamp: hwtstamp transformed to system time base 194 * 195 * Software time stamps generated by ktime_get_real() are stored in 196 * skb->tstamp. The relation between the different kinds of time 197 * stamps is as follows: 198 * 199 * syststamp and tstamp can be compared against each other in 200 * arbitrary combinations. The accuracy of a 201 * syststamp/tstamp/"syststamp from other device" comparison is 202 * limited by the accuracy of the transformation into system time 203 * base. This depends on the device driver and its underlying 204 * hardware. 205 * 206 * hwtstamps can only be compared against other hwtstamps from 207 * the same device. 208 * 209 * This structure is attached to packets as part of the 210 * &skb_shared_info. Use skb_hwtstamps() to get a pointer. 211 */ 212 struct skb_shared_hwtstamps { 213 ktime_t hwtstamp; 214 ktime_t syststamp; 215 }; 216 217 /* Definitions for tx_flags in struct skb_shared_info */ 218 enum { 219 /* generate hardware time stamp */ 220 SKBTX_HW_TSTAMP = 1 << 0, 221 222 /* generate software time stamp */ 223 SKBTX_SW_TSTAMP = 1 << 1, 224 225 /* device driver is going to provide hardware time stamp */ 226 SKBTX_IN_PROGRESS = 1 << 2, 227 228 /* ensure the originating sk reference is available on driver level */ 229 SKBTX_DRV_NEEDS_SK_REF = 1 << 3, 230 231 /* device driver supports TX zero-copy buffers */ 232 SKBTX_DEV_ZEROCOPY = 1 << 4, 233 234 /* generate wifi status information (where possible) */ 235 SKBTX_WIFI_STATUS = 1 << 5, 236 }; 237 238 /* 239 * The callback notifies userspace to release buffers when skb DMA is done in 240 * lower device, the skb last reference should be 0 when calling this. 241 * The ctx field is used to track device context. 242 * The desc field is used to track userspace buffer index. 243 */ 244 struct ubuf_info { 245 void (*callback)(struct ubuf_info *); 246 void *ctx; 247 unsigned long desc; 248 }; 249 250 /* This data is invariant across clones and lives at 251 * the end of the header data, ie. at skb->end. 252 */ 253 struct skb_shared_info { 254 unsigned char nr_frags; 255 __u8 tx_flags; 256 unsigned short gso_size; 257 /* Warning: this field is not always filled in (UFO)! */ 258 unsigned short gso_segs; 259 unsigned short gso_type; 260 struct sk_buff *frag_list; 261 struct skb_shared_hwtstamps hwtstamps; 262 __be32 ip6_frag_id; 263 264 /* 265 * Warning : all fields before dataref are cleared in __alloc_skb() 266 */ 267 atomic_t dataref; 268 269 /* Intermediate layers must ensure that destructor_arg 270 * remains valid until skb destructor */ 271 void * destructor_arg; 272 273 /* must be last field, see pskb_expand_head() */ 274 skb_frag_t frags[MAX_SKB_FRAGS]; 275 }; 276 277 /* We divide dataref into two halves. The higher 16 bits hold references 278 * to the payload part of skb->data. The lower 16 bits hold references to 279 * the entire skb->data. A clone of a headerless skb holds the length of 280 * the header in skb->hdr_len. 281 * 282 * All users must obey the rule that the skb->data reference count must be 283 * greater than or equal to the payload reference count. 284 * 285 * Holding a reference to the payload part means that the user does not 286 * care about modifications to the header part of skb->data. 287 */ 288 #define SKB_DATAREF_SHIFT 16 289 #define SKB_DATAREF_MASK ((1 << SKB_DATAREF_SHIFT) - 1) 290 291 292 enum { 293 SKB_FCLONE_UNAVAILABLE, 294 SKB_FCLONE_ORIG, 295 SKB_FCLONE_CLONE, 296 }; 297 298 enum { 299 SKB_GSO_TCPV4 = 1 << 0, 300 SKB_GSO_UDP = 1 << 1, 301 302 /* This indicates the skb is from an untrusted source. */ 303 SKB_GSO_DODGY = 1 << 2, 304 305 /* This indicates the tcp segment has CWR set. */ 306 SKB_GSO_TCP_ECN = 1 << 3, 307 308 SKB_GSO_TCPV6 = 1 << 4, 309 310 SKB_GSO_FCOE = 1 << 5, 311 }; 312 313 #if BITS_PER_LONG > 32 314 #define NET_SKBUFF_DATA_USES_OFFSET 1 315 #endif 316 317 #ifdef NET_SKBUFF_DATA_USES_OFFSET 318 typedef unsigned int sk_buff_data_t; 319 #else 320 typedef unsigned char *sk_buff_data_t; 321 #endif 322 323 #if defined(CONFIG_NF_DEFRAG_IPV4) || defined(CONFIG_NF_DEFRAG_IPV4_MODULE) || \ 324 defined(CONFIG_NF_DEFRAG_IPV6) || defined(CONFIG_NF_DEFRAG_IPV6_MODULE) 325 #define NET_SKBUFF_NF_DEFRAG_NEEDED 1 326 #endif 327 328 /** 329 * struct sk_buff - socket buffer 330 * @next: Next buffer in list 331 * @prev: Previous buffer in list 332 * @tstamp: Time we arrived 333 * @sk: Socket we are owned by 334 * @dev: Device we arrived on/are leaving by 335 * @cb: Control buffer. Free for use by every layer. Put private vars here 336 * @_skb_refdst: destination entry (with norefcount bit) 337 * @sp: the security path, used for xfrm 338 * @len: Length of actual data 339 * @data_len: Data length 340 * @mac_len: Length of link layer header 341 * @hdr_len: writable header length of cloned skb 342 * @csum: Checksum (must include start/offset pair) 343 * @csum_start: Offset from skb->head where checksumming should start 344 * @csum_offset: Offset from csum_start where checksum should be stored 345 * @priority: Packet queueing priority 346 * @local_df: allow local fragmentation 347 * @cloned: Head may be cloned (check refcnt to be sure) 348 * @ip_summed: Driver fed us an IP checksum 349 * @nohdr: Payload reference only, must not modify header 350 * @nfctinfo: Relationship of this skb to the connection 351 * @pkt_type: Packet class 352 * @fclone: skbuff clone status 353 * @ipvs_property: skbuff is owned by ipvs 354 * @peeked: this packet has been seen already, so stats have been 355 * done for it, don't do them again 356 * @nf_trace: netfilter packet trace flag 357 * @protocol: Packet protocol from driver 358 * @destructor: Destruct function 359 * @nfct: Associated connection, if any 360 * @nfct_reasm: netfilter conntrack re-assembly pointer 361 * @nf_bridge: Saved data about a bridged frame - see br_netfilter.c 362 * @skb_iif: ifindex of device we arrived on 363 * @tc_index: Traffic control index 364 * @tc_verd: traffic control verdict 365 * @rxhash: the packet hash computed on receive 366 * @queue_mapping: Queue mapping for multiqueue devices 367 * @ndisc_nodetype: router type (from link layer) 368 * @ooo_okay: allow the mapping of a socket to a queue to be changed 369 * @l4_rxhash: indicate rxhash is a canonical 4-tuple hash over transport 370 * ports. 371 * @wifi_acked_valid: wifi_acked was set 372 * @wifi_acked: whether frame was acked on wifi or not 373 * @no_fcs: Request NIC to treat last 4 bytes as Ethernet FCS 374 * @dma_cookie: a cookie to one of several possible DMA operations 375 * done by skb DMA functions 376 * @secmark: security marking 377 * @mark: Generic packet mark 378 * @dropcount: total number of sk_receive_queue overflows 379 * @vlan_tci: vlan tag control information 380 * @transport_header: Transport layer header 381 * @network_header: Network layer header 382 * @mac_header: Link layer header 383 * @tail: Tail pointer 384 * @end: End pointer 385 * @head: Head of buffer 386 * @data: Data head pointer 387 * @truesize: Buffer size 388 * @users: User count - see {datagram,tcp}.c 389 */ 390 391 struct sk_buff { 392 /* These two members must be first. */ 393 struct sk_buff *next; 394 struct sk_buff *prev; 395 396 ktime_t tstamp; 397 398 struct sock *sk; 399 struct net_device *dev; 400 401 /* 402 * This is the control buffer. It is free to use for every 403 * layer. Please put your private variables there. If you 404 * want to keep them across layers you have to do a skb_clone() 405 * first. This is owned by whoever has the skb queued ATM. 406 */ 407 char cb[48] __aligned(8); 408 409 unsigned long _skb_refdst; 410 #ifdef CONFIG_XFRM 411 struct sec_path *sp; 412 #endif 413 unsigned int len, 414 data_len; 415 __u16 mac_len, 416 hdr_len; 417 union { 418 __wsum csum; 419 struct { 420 __u16 csum_start; 421 __u16 csum_offset; 422 }; 423 }; 424 __u32 priority; 425 kmemcheck_bitfield_begin(flags1); 426 __u8 local_df:1, 427 cloned:1, 428 ip_summed:2, 429 nohdr:1, 430 nfctinfo:3; 431 __u8 pkt_type:3, 432 fclone:2, 433 ipvs_property:1, 434 peeked:1, 435 nf_trace:1; 436 kmemcheck_bitfield_end(flags1); 437 __be16 protocol; 438 439 void (*destructor)(struct sk_buff *skb); 440 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE) 441 struct nf_conntrack *nfct; 442 #endif 443 #ifdef NET_SKBUFF_NF_DEFRAG_NEEDED 444 struct sk_buff *nfct_reasm; 445 #endif 446 #ifdef CONFIG_BRIDGE_NETFILTER 447 struct nf_bridge_info *nf_bridge; 448 #endif 449 450 int skb_iif; 451 452 __u32 rxhash; 453 454 __u16 vlan_tci; 455 456 #ifdef CONFIG_NET_SCHED 457 __u16 tc_index; /* traffic control index */ 458 #ifdef CONFIG_NET_CLS_ACT 459 __u16 tc_verd; /* traffic control verdict */ 460 #endif 461 #endif 462 463 __u16 queue_mapping; 464 kmemcheck_bitfield_begin(flags2); 465 #ifdef CONFIG_IPV6_NDISC_NODETYPE 466 __u8 ndisc_nodetype:2; 467 #endif 468 __u8 ooo_okay:1; 469 __u8 l4_rxhash:1; 470 __u8 wifi_acked_valid:1; 471 __u8 wifi_acked:1; 472 __u8 no_fcs:1; 473 __u8 head_frag:1; 474 /* 8/10 bit hole (depending on ndisc_nodetype presence) */ 475 kmemcheck_bitfield_end(flags2); 476 477 #ifdef CONFIG_NET_DMA 478 dma_cookie_t dma_cookie; 479 #endif 480 #ifdef CONFIG_NETWORK_SECMARK 481 __u32 secmark; 482 #endif 483 union { 484 __u32 mark; 485 __u32 dropcount; 486 __u32 avail_size; 487 }; 488 489 sk_buff_data_t transport_header; 490 sk_buff_data_t network_header; 491 sk_buff_data_t mac_header; 492 /* These elements must be at the end, see alloc_skb() for details. */ 493 sk_buff_data_t tail; 494 sk_buff_data_t end; 495 unsigned char *head, 496 *data; 497 unsigned int truesize; 498 atomic_t users; 499 }; 500 501 #ifdef __KERNEL__ 502 /* 503 * Handling routines are only of interest to the kernel 504 */ 505 #include <linux/slab.h> 506 507 508 /* 509 * skb might have a dst pointer attached, refcounted or not. 510 * _skb_refdst low order bit is set if refcount was _not_ taken 511 */ 512 #define SKB_DST_NOREF 1UL 513 #define SKB_DST_PTRMASK ~(SKB_DST_NOREF) 514 515 /** 516 * skb_dst - returns skb dst_entry 517 * @skb: buffer 518 * 519 * Returns skb dst_entry, regardless of reference taken or not. 520 */ 521 static inline struct dst_entry *skb_dst(const struct sk_buff *skb) 522 { 523 /* If refdst was not refcounted, check we still are in a 524 * rcu_read_lock section 525 */ 526 WARN_ON((skb->_skb_refdst & SKB_DST_NOREF) && 527 !rcu_read_lock_held() && 528 !rcu_read_lock_bh_held()); 529 return (struct dst_entry *)(skb->_skb_refdst & SKB_DST_PTRMASK); 530 } 531 532 /** 533 * skb_dst_set - sets skb dst 534 * @skb: buffer 535 * @dst: dst entry 536 * 537 * Sets skb dst, assuming a reference was taken on dst and should 538 * be released by skb_dst_drop() 539 */ 540 static inline void skb_dst_set(struct sk_buff *skb, struct dst_entry *dst) 541 { 542 skb->_skb_refdst = (unsigned long)dst; 543 } 544 545 extern void skb_dst_set_noref(struct sk_buff *skb, struct dst_entry *dst); 546 547 /** 548 * skb_dst_is_noref - Test if skb dst isn't refcounted 549 * @skb: buffer 550 */ 551 static inline bool skb_dst_is_noref(const struct sk_buff *skb) 552 { 553 return (skb->_skb_refdst & SKB_DST_NOREF) && skb_dst(skb); 554 } 555 556 static inline struct rtable *skb_rtable(const struct sk_buff *skb) 557 { 558 return (struct rtable *)skb_dst(skb); 559 } 560 561 extern void kfree_skb(struct sk_buff *skb); 562 extern void consume_skb(struct sk_buff *skb); 563 extern void __kfree_skb(struct sk_buff *skb); 564 extern struct kmem_cache *skbuff_head_cache; 565 566 extern void kfree_skb_partial(struct sk_buff *skb, bool head_stolen); 567 extern bool skb_try_coalesce(struct sk_buff *to, struct sk_buff *from, 568 bool *fragstolen, int *delta_truesize); 569 570 extern struct sk_buff *__alloc_skb(unsigned int size, 571 gfp_t priority, int fclone, int node); 572 extern struct sk_buff *build_skb(void *data, unsigned int frag_size); 573 static inline struct sk_buff *alloc_skb(unsigned int size, 574 gfp_t priority) 575 { 576 return __alloc_skb(size, priority, 0, NUMA_NO_NODE); 577 } 578 579 static inline struct sk_buff *alloc_skb_fclone(unsigned int size, 580 gfp_t priority) 581 { 582 return __alloc_skb(size, priority, 1, NUMA_NO_NODE); 583 } 584 585 extern void skb_recycle(struct sk_buff *skb); 586 extern bool skb_recycle_check(struct sk_buff *skb, int skb_size); 587 588 extern struct sk_buff *skb_morph(struct sk_buff *dst, struct sk_buff *src); 589 extern int skb_copy_ubufs(struct sk_buff *skb, gfp_t gfp_mask); 590 extern struct sk_buff *skb_clone(struct sk_buff *skb, 591 gfp_t priority); 592 extern struct sk_buff *skb_copy(const struct sk_buff *skb, 593 gfp_t priority); 594 extern struct sk_buff *__pskb_copy(struct sk_buff *skb, 595 int headroom, gfp_t gfp_mask); 596 597 extern int pskb_expand_head(struct sk_buff *skb, 598 int nhead, int ntail, 599 gfp_t gfp_mask); 600 extern struct sk_buff *skb_realloc_headroom(struct sk_buff *skb, 601 unsigned int headroom); 602 extern struct sk_buff *skb_copy_expand(const struct sk_buff *skb, 603 int newheadroom, int newtailroom, 604 gfp_t priority); 605 extern int skb_to_sgvec(struct sk_buff *skb, 606 struct scatterlist *sg, int offset, 607 int len); 608 extern int skb_cow_data(struct sk_buff *skb, int tailbits, 609 struct sk_buff **trailer); 610 extern int skb_pad(struct sk_buff *skb, int pad); 611 #define dev_kfree_skb(a) consume_skb(a) 612 613 extern int skb_append_datato_frags(struct sock *sk, struct sk_buff *skb, 614 int getfrag(void *from, char *to, int offset, 615 int len,int odd, struct sk_buff *skb), 616 void *from, int length); 617 618 struct skb_seq_state { 619 __u32 lower_offset; 620 __u32 upper_offset; 621 __u32 frag_idx; 622 __u32 stepped_offset; 623 struct sk_buff *root_skb; 624 struct sk_buff *cur_skb; 625 __u8 *frag_data; 626 }; 627 628 extern void skb_prepare_seq_read(struct sk_buff *skb, 629 unsigned int from, unsigned int to, 630 struct skb_seq_state *st); 631 extern unsigned int skb_seq_read(unsigned int consumed, const u8 **data, 632 struct skb_seq_state *st); 633 extern void skb_abort_seq_read(struct skb_seq_state *st); 634 635 extern unsigned int skb_find_text(struct sk_buff *skb, unsigned int from, 636 unsigned int to, struct ts_config *config, 637 struct ts_state *state); 638 639 extern void __skb_get_rxhash(struct sk_buff *skb); 640 static inline __u32 skb_get_rxhash(struct sk_buff *skb) 641 { 642 if (!skb->rxhash) 643 __skb_get_rxhash(skb); 644 645 return skb->rxhash; 646 } 647 648 #ifdef NET_SKBUFF_DATA_USES_OFFSET 649 static inline unsigned char *skb_end_pointer(const struct sk_buff *skb) 650 { 651 return skb->head + skb->end; 652 } 653 654 static inline unsigned int skb_end_offset(const struct sk_buff *skb) 655 { 656 return skb->end; 657 } 658 #else 659 static inline unsigned char *skb_end_pointer(const struct sk_buff *skb) 660 { 661 return skb->end; 662 } 663 664 static inline unsigned int skb_end_offset(const struct sk_buff *skb) 665 { 666 return skb->end - skb->head; 667 } 668 #endif 669 670 /* Internal */ 671 #define skb_shinfo(SKB) ((struct skb_shared_info *)(skb_end_pointer(SKB))) 672 673 static inline struct skb_shared_hwtstamps *skb_hwtstamps(struct sk_buff *skb) 674 { 675 return &skb_shinfo(skb)->hwtstamps; 676 } 677 678 /** 679 * skb_queue_empty - check if a queue is empty 680 * @list: queue head 681 * 682 * Returns true if the queue is empty, false otherwise. 683 */ 684 static inline int skb_queue_empty(const struct sk_buff_head *list) 685 { 686 return list->next == (struct sk_buff *)list; 687 } 688 689 /** 690 * skb_queue_is_last - check if skb is the last entry in the queue 691 * @list: queue head 692 * @skb: buffer 693 * 694 * Returns true if @skb is the last buffer on the list. 695 */ 696 static inline bool skb_queue_is_last(const struct sk_buff_head *list, 697 const struct sk_buff *skb) 698 { 699 return skb->next == (struct sk_buff *)list; 700 } 701 702 /** 703 * skb_queue_is_first - check if skb is the first entry in the queue 704 * @list: queue head 705 * @skb: buffer 706 * 707 * Returns true if @skb is the first buffer on the list. 708 */ 709 static inline bool skb_queue_is_first(const struct sk_buff_head *list, 710 const struct sk_buff *skb) 711 { 712 return skb->prev == (struct sk_buff *)list; 713 } 714 715 /** 716 * skb_queue_next - return the next packet in the queue 717 * @list: queue head 718 * @skb: current buffer 719 * 720 * Return the next packet in @list after @skb. It is only valid to 721 * call this if skb_queue_is_last() evaluates to false. 722 */ 723 static inline struct sk_buff *skb_queue_next(const struct sk_buff_head *list, 724 const struct sk_buff *skb) 725 { 726 /* This BUG_ON may seem severe, but if we just return then we 727 * are going to dereference garbage. 728 */ 729 BUG_ON(skb_queue_is_last(list, skb)); 730 return skb->next; 731 } 732 733 /** 734 * skb_queue_prev - return the prev packet in the queue 735 * @list: queue head 736 * @skb: current buffer 737 * 738 * Return the prev packet in @list before @skb. It is only valid to 739 * call this if skb_queue_is_first() evaluates to false. 740 */ 741 static inline struct sk_buff *skb_queue_prev(const struct sk_buff_head *list, 742 const struct sk_buff *skb) 743 { 744 /* This BUG_ON may seem severe, but if we just return then we 745 * are going to dereference garbage. 746 */ 747 BUG_ON(skb_queue_is_first(list, skb)); 748 return skb->prev; 749 } 750 751 /** 752 * skb_get - reference buffer 753 * @skb: buffer to reference 754 * 755 * Makes another reference to a socket buffer and returns a pointer 756 * to the buffer. 757 */ 758 static inline struct sk_buff *skb_get(struct sk_buff *skb) 759 { 760 atomic_inc(&skb->users); 761 return skb; 762 } 763 764 /* 765 * If users == 1, we are the only owner and are can avoid redundant 766 * atomic change. 767 */ 768 769 /** 770 * skb_cloned - is the buffer a clone 771 * @skb: buffer to check 772 * 773 * Returns true if the buffer was generated with skb_clone() and is 774 * one of multiple shared copies of the buffer. Cloned buffers are 775 * shared data so must not be written to under normal circumstances. 776 */ 777 static inline int skb_cloned(const struct sk_buff *skb) 778 { 779 return skb->cloned && 780 (atomic_read(&skb_shinfo(skb)->dataref) & SKB_DATAREF_MASK) != 1; 781 } 782 783 /** 784 * skb_header_cloned - is the header a clone 785 * @skb: buffer to check 786 * 787 * Returns true if modifying the header part of the buffer requires 788 * the data to be copied. 789 */ 790 static inline int skb_header_cloned(const struct sk_buff *skb) 791 { 792 int dataref; 793 794 if (!skb->cloned) 795 return 0; 796 797 dataref = atomic_read(&skb_shinfo(skb)->dataref); 798 dataref = (dataref & SKB_DATAREF_MASK) - (dataref >> SKB_DATAREF_SHIFT); 799 return dataref != 1; 800 } 801 802 /** 803 * skb_header_release - release reference to header 804 * @skb: buffer to operate on 805 * 806 * Drop a reference to the header part of the buffer. This is done 807 * by acquiring a payload reference. You must not read from the header 808 * part of skb->data after this. 809 */ 810 static inline void skb_header_release(struct sk_buff *skb) 811 { 812 BUG_ON(skb->nohdr); 813 skb->nohdr = 1; 814 atomic_add(1 << SKB_DATAREF_SHIFT, &skb_shinfo(skb)->dataref); 815 } 816 817 /** 818 * skb_shared - is the buffer shared 819 * @skb: buffer to check 820 * 821 * Returns true if more than one person has a reference to this 822 * buffer. 823 */ 824 static inline int skb_shared(const struct sk_buff *skb) 825 { 826 return atomic_read(&skb->users) != 1; 827 } 828 829 /** 830 * skb_share_check - check if buffer is shared and if so clone it 831 * @skb: buffer to check 832 * @pri: priority for memory allocation 833 * 834 * If the buffer is shared the buffer is cloned and the old copy 835 * drops a reference. A new clone with a single reference is returned. 836 * If the buffer is not shared the original buffer is returned. When 837 * being called from interrupt status or with spinlocks held pri must 838 * be GFP_ATOMIC. 839 * 840 * NULL is returned on a memory allocation failure. 841 */ 842 static inline struct sk_buff *skb_share_check(struct sk_buff *skb, 843 gfp_t pri) 844 { 845 might_sleep_if(pri & __GFP_WAIT); 846 if (skb_shared(skb)) { 847 struct sk_buff *nskb = skb_clone(skb, pri); 848 kfree_skb(skb); 849 skb = nskb; 850 } 851 return skb; 852 } 853 854 /* 855 * Copy shared buffers into a new sk_buff. We effectively do COW on 856 * packets to handle cases where we have a local reader and forward 857 * and a couple of other messy ones. The normal one is tcpdumping 858 * a packet thats being forwarded. 859 */ 860 861 /** 862 * skb_unshare - make a copy of a shared buffer 863 * @skb: buffer to check 864 * @pri: priority for memory allocation 865 * 866 * If the socket buffer is a clone then this function creates a new 867 * copy of the data, drops a reference count on the old copy and returns 868 * the new copy with the reference count at 1. If the buffer is not a clone 869 * the original buffer is returned. When called with a spinlock held or 870 * from interrupt state @pri must be %GFP_ATOMIC 871 * 872 * %NULL is returned on a memory allocation failure. 873 */ 874 static inline struct sk_buff *skb_unshare(struct sk_buff *skb, 875 gfp_t pri) 876 { 877 might_sleep_if(pri & __GFP_WAIT); 878 if (skb_cloned(skb)) { 879 struct sk_buff *nskb = skb_copy(skb, pri); 880 kfree_skb(skb); /* Free our shared copy */ 881 skb = nskb; 882 } 883 return skb; 884 } 885 886 /** 887 * skb_peek - peek at the head of an &sk_buff_head 888 * @list_: list to peek at 889 * 890 * Peek an &sk_buff. Unlike most other operations you _MUST_ 891 * be careful with this one. A peek leaves the buffer on the 892 * list and someone else may run off with it. You must hold 893 * the appropriate locks or have a private queue to do this. 894 * 895 * Returns %NULL for an empty list or a pointer to the head element. 896 * The reference count is not incremented and the reference is therefore 897 * volatile. Use with caution. 898 */ 899 static inline struct sk_buff *skb_peek(const struct sk_buff_head *list_) 900 { 901 struct sk_buff *skb = list_->next; 902 903 if (skb == (struct sk_buff *)list_) 904 skb = NULL; 905 return skb; 906 } 907 908 /** 909 * skb_peek_next - peek skb following the given one from a queue 910 * @skb: skb to start from 911 * @list_: list to peek at 912 * 913 * Returns %NULL when the end of the list is met or a pointer to the 914 * next element. The reference count is not incremented and the 915 * reference is therefore volatile. Use with caution. 916 */ 917 static inline struct sk_buff *skb_peek_next(struct sk_buff *skb, 918 const struct sk_buff_head *list_) 919 { 920 struct sk_buff *next = skb->next; 921 922 if (next == (struct sk_buff *)list_) 923 next = NULL; 924 return next; 925 } 926 927 /** 928 * skb_peek_tail - peek at the tail of an &sk_buff_head 929 * @list_: list to peek at 930 * 931 * Peek an &sk_buff. Unlike most other operations you _MUST_ 932 * be careful with this one. A peek leaves the buffer on the 933 * list and someone else may run off with it. You must hold 934 * the appropriate locks or have a private queue to do this. 935 * 936 * Returns %NULL for an empty list or a pointer to the tail element. 937 * The reference count is not incremented and the reference is therefore 938 * volatile. Use with caution. 939 */ 940 static inline struct sk_buff *skb_peek_tail(const struct sk_buff_head *list_) 941 { 942 struct sk_buff *skb = list_->prev; 943 944 if (skb == (struct sk_buff *)list_) 945 skb = NULL; 946 return skb; 947 948 } 949 950 /** 951 * skb_queue_len - get queue length 952 * @list_: list to measure 953 * 954 * Return the length of an &sk_buff queue. 955 */ 956 static inline __u32 skb_queue_len(const struct sk_buff_head *list_) 957 { 958 return list_->qlen; 959 } 960 961 /** 962 * __skb_queue_head_init - initialize non-spinlock portions of sk_buff_head 963 * @list: queue to initialize 964 * 965 * This initializes only the list and queue length aspects of 966 * an sk_buff_head object. This allows to initialize the list 967 * aspects of an sk_buff_head without reinitializing things like 968 * the spinlock. It can also be used for on-stack sk_buff_head 969 * objects where the spinlock is known to not be used. 970 */ 971 static inline void __skb_queue_head_init(struct sk_buff_head *list) 972 { 973 list->prev = list->next = (struct sk_buff *)list; 974 list->qlen = 0; 975 } 976 977 /* 978 * This function creates a split out lock class for each invocation; 979 * this is needed for now since a whole lot of users of the skb-queue 980 * infrastructure in drivers have different locking usage (in hardirq) 981 * than the networking core (in softirq only). In the long run either the 982 * network layer or drivers should need annotation to consolidate the 983 * main types of usage into 3 classes. 984 */ 985 static inline void skb_queue_head_init(struct sk_buff_head *list) 986 { 987 spin_lock_init(&list->lock); 988 __skb_queue_head_init(list); 989 } 990 991 static inline void skb_queue_head_init_class(struct sk_buff_head *list, 992 struct lock_class_key *class) 993 { 994 skb_queue_head_init(list); 995 lockdep_set_class(&list->lock, class); 996 } 997 998 /* 999 * Insert an sk_buff on a list. 1000 * 1001 * The "__skb_xxxx()" functions are the non-atomic ones that 1002 * can only be called with interrupts disabled. 1003 */ 1004 extern void skb_insert(struct sk_buff *old, struct sk_buff *newsk, struct sk_buff_head *list); 1005 static inline void __skb_insert(struct sk_buff *newsk, 1006 struct sk_buff *prev, struct sk_buff *next, 1007 struct sk_buff_head *list) 1008 { 1009 newsk->next = next; 1010 newsk->prev = prev; 1011 next->prev = prev->next = newsk; 1012 list->qlen++; 1013 } 1014 1015 static inline void __skb_queue_splice(const struct sk_buff_head *list, 1016 struct sk_buff *prev, 1017 struct sk_buff *next) 1018 { 1019 struct sk_buff *first = list->next; 1020 struct sk_buff *last = list->prev; 1021 1022 first->prev = prev; 1023 prev->next = first; 1024 1025 last->next = next; 1026 next->prev = last; 1027 } 1028 1029 /** 1030 * skb_queue_splice - join two skb lists, this is designed for stacks 1031 * @list: the new list to add 1032 * @head: the place to add it in the first list 1033 */ 1034 static inline void skb_queue_splice(const struct sk_buff_head *list, 1035 struct sk_buff_head *head) 1036 { 1037 if (!skb_queue_empty(list)) { 1038 __skb_queue_splice(list, (struct sk_buff *) head, head->next); 1039 head->qlen += list->qlen; 1040 } 1041 } 1042 1043 /** 1044 * skb_queue_splice_init - join two skb lists and reinitialise the emptied list 1045 * @list: the new list to add 1046 * @head: the place to add it in the first list 1047 * 1048 * The list at @list is reinitialised 1049 */ 1050 static inline void skb_queue_splice_init(struct sk_buff_head *list, 1051 struct sk_buff_head *head) 1052 { 1053 if (!skb_queue_empty(list)) { 1054 __skb_queue_splice(list, (struct sk_buff *) head, head->next); 1055 head->qlen += list->qlen; 1056 __skb_queue_head_init(list); 1057 } 1058 } 1059 1060 /** 1061 * skb_queue_splice_tail - join two skb lists, each list being a queue 1062 * @list: the new list to add 1063 * @head: the place to add it in the first list 1064 */ 1065 static inline void skb_queue_splice_tail(const struct sk_buff_head *list, 1066 struct sk_buff_head *head) 1067 { 1068 if (!skb_queue_empty(list)) { 1069 __skb_queue_splice(list, head->prev, (struct sk_buff *) head); 1070 head->qlen += list->qlen; 1071 } 1072 } 1073 1074 /** 1075 * skb_queue_splice_tail_init - join two skb lists and reinitialise the emptied list 1076 * @list: the new list to add 1077 * @head: the place to add it in the first list 1078 * 1079 * Each of the lists is a queue. 1080 * The list at @list is reinitialised 1081 */ 1082 static inline void skb_queue_splice_tail_init(struct sk_buff_head *list, 1083 struct sk_buff_head *head) 1084 { 1085 if (!skb_queue_empty(list)) { 1086 __skb_queue_splice(list, head->prev, (struct sk_buff *) head); 1087 head->qlen += list->qlen; 1088 __skb_queue_head_init(list); 1089 } 1090 } 1091 1092 /** 1093 * __skb_queue_after - queue a buffer at the list head 1094 * @list: list to use 1095 * @prev: place after this buffer 1096 * @newsk: buffer to queue 1097 * 1098 * Queue a buffer int the middle of a list. This function takes no locks 1099 * and you must therefore hold required locks before calling it. 1100 * 1101 * A buffer cannot be placed on two lists at the same time. 1102 */ 1103 static inline void __skb_queue_after(struct sk_buff_head *list, 1104 struct sk_buff *prev, 1105 struct sk_buff *newsk) 1106 { 1107 __skb_insert(newsk, prev, prev->next, list); 1108 } 1109 1110 extern void skb_append(struct sk_buff *old, struct sk_buff *newsk, 1111 struct sk_buff_head *list); 1112 1113 static inline void __skb_queue_before(struct sk_buff_head *list, 1114 struct sk_buff *next, 1115 struct sk_buff *newsk) 1116 { 1117 __skb_insert(newsk, next->prev, next, list); 1118 } 1119 1120 /** 1121 * __skb_queue_head - queue a buffer at the list head 1122 * @list: list to use 1123 * @newsk: buffer to queue 1124 * 1125 * Queue a buffer at the start of a list. This function takes no locks 1126 * and you must therefore hold required locks before calling it. 1127 * 1128 * A buffer cannot be placed on two lists at the same time. 1129 */ 1130 extern void skb_queue_head(struct sk_buff_head *list, struct sk_buff *newsk); 1131 static inline void __skb_queue_head(struct sk_buff_head *list, 1132 struct sk_buff *newsk) 1133 { 1134 __skb_queue_after(list, (struct sk_buff *)list, newsk); 1135 } 1136 1137 /** 1138 * __skb_queue_tail - queue a buffer at the list tail 1139 * @list: list to use 1140 * @newsk: buffer to queue 1141 * 1142 * Queue a buffer at the end of a list. This function takes no locks 1143 * and you must therefore hold required locks before calling it. 1144 * 1145 * A buffer cannot be placed on two lists at the same time. 1146 */ 1147 extern void skb_queue_tail(struct sk_buff_head *list, struct sk_buff *newsk); 1148 static inline void __skb_queue_tail(struct sk_buff_head *list, 1149 struct sk_buff *newsk) 1150 { 1151 __skb_queue_before(list, (struct sk_buff *)list, newsk); 1152 } 1153 1154 /* 1155 * remove sk_buff from list. _Must_ be called atomically, and with 1156 * the list known.. 1157 */ 1158 extern void skb_unlink(struct sk_buff *skb, struct sk_buff_head *list); 1159 static inline void __skb_unlink(struct sk_buff *skb, struct sk_buff_head *list) 1160 { 1161 struct sk_buff *next, *prev; 1162 1163 list->qlen--; 1164 next = skb->next; 1165 prev = skb->prev; 1166 skb->next = skb->prev = NULL; 1167 next->prev = prev; 1168 prev->next = next; 1169 } 1170 1171 /** 1172 * __skb_dequeue - remove from the head of the queue 1173 * @list: list to dequeue from 1174 * 1175 * Remove the head of the list. This function does not take any locks 1176 * so must be used with appropriate locks held only. The head item is 1177 * returned or %NULL if the list is empty. 1178 */ 1179 extern struct sk_buff *skb_dequeue(struct sk_buff_head *list); 1180 static inline struct sk_buff *__skb_dequeue(struct sk_buff_head *list) 1181 { 1182 struct sk_buff *skb = skb_peek(list); 1183 if (skb) 1184 __skb_unlink(skb, list); 1185 return skb; 1186 } 1187 1188 /** 1189 * __skb_dequeue_tail - remove from the tail of the queue 1190 * @list: list to dequeue from 1191 * 1192 * Remove the tail of the list. This function does not take any locks 1193 * so must be used with appropriate locks held only. The tail item is 1194 * returned or %NULL if the list is empty. 1195 */ 1196 extern struct sk_buff *skb_dequeue_tail(struct sk_buff_head *list); 1197 static inline struct sk_buff *__skb_dequeue_tail(struct sk_buff_head *list) 1198 { 1199 struct sk_buff *skb = skb_peek_tail(list); 1200 if (skb) 1201 __skb_unlink(skb, list); 1202 return skb; 1203 } 1204 1205 1206 static inline bool skb_is_nonlinear(const struct sk_buff *skb) 1207 { 1208 return skb->data_len; 1209 } 1210 1211 static inline unsigned int skb_headlen(const struct sk_buff *skb) 1212 { 1213 return skb->len - skb->data_len; 1214 } 1215 1216 static inline int skb_pagelen(const struct sk_buff *skb) 1217 { 1218 int i, len = 0; 1219 1220 for (i = (int)skb_shinfo(skb)->nr_frags - 1; i >= 0; i--) 1221 len += skb_frag_size(&skb_shinfo(skb)->frags[i]); 1222 return len + skb_headlen(skb); 1223 } 1224 1225 /** 1226 * __skb_fill_page_desc - initialise a paged fragment in an skb 1227 * @skb: buffer containing fragment to be initialised 1228 * @i: paged fragment index to initialise 1229 * @page: the page to use for this fragment 1230 * @off: the offset to the data with @page 1231 * @size: the length of the data 1232 * 1233 * Initialises the @i'th fragment of @skb to point to &size bytes at 1234 * offset @off within @page. 1235 * 1236 * Does not take any additional reference on the fragment. 1237 */ 1238 static inline void __skb_fill_page_desc(struct sk_buff *skb, int i, 1239 struct page *page, int off, int size) 1240 { 1241 skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; 1242 1243 frag->page.p = page; 1244 frag->page_offset = off; 1245 skb_frag_size_set(frag, size); 1246 } 1247 1248 /** 1249 * skb_fill_page_desc - initialise a paged fragment in an skb 1250 * @skb: buffer containing fragment to be initialised 1251 * @i: paged fragment index to initialise 1252 * @page: the page to use for this fragment 1253 * @off: the offset to the data with @page 1254 * @size: the length of the data 1255 * 1256 * As per __skb_fill_page_desc() -- initialises the @i'th fragment of 1257 * @skb to point to &size bytes at offset @off within @page. In 1258 * addition updates @skb such that @i is the last fragment. 1259 * 1260 * Does not take any additional reference on the fragment. 1261 */ 1262 static inline void skb_fill_page_desc(struct sk_buff *skb, int i, 1263 struct page *page, int off, int size) 1264 { 1265 __skb_fill_page_desc(skb, i, page, off, size); 1266 skb_shinfo(skb)->nr_frags = i + 1; 1267 } 1268 1269 extern void skb_add_rx_frag(struct sk_buff *skb, int i, struct page *page, 1270 int off, int size, unsigned int truesize); 1271 1272 #define SKB_PAGE_ASSERT(skb) BUG_ON(skb_shinfo(skb)->nr_frags) 1273 #define SKB_FRAG_ASSERT(skb) BUG_ON(skb_has_frag_list(skb)) 1274 #define SKB_LINEAR_ASSERT(skb) BUG_ON(skb_is_nonlinear(skb)) 1275 1276 #ifdef NET_SKBUFF_DATA_USES_OFFSET 1277 static inline unsigned char *skb_tail_pointer(const struct sk_buff *skb) 1278 { 1279 return skb->head + skb->tail; 1280 } 1281 1282 static inline void skb_reset_tail_pointer(struct sk_buff *skb) 1283 { 1284 skb->tail = skb->data - skb->head; 1285 } 1286 1287 static inline void skb_set_tail_pointer(struct sk_buff *skb, const int offset) 1288 { 1289 skb_reset_tail_pointer(skb); 1290 skb->tail += offset; 1291 } 1292 #else /* NET_SKBUFF_DATA_USES_OFFSET */ 1293 static inline unsigned char *skb_tail_pointer(const struct sk_buff *skb) 1294 { 1295 return skb->tail; 1296 } 1297 1298 static inline void skb_reset_tail_pointer(struct sk_buff *skb) 1299 { 1300 skb->tail = skb->data; 1301 } 1302 1303 static inline void skb_set_tail_pointer(struct sk_buff *skb, const int offset) 1304 { 1305 skb->tail = skb->data + offset; 1306 } 1307 1308 #endif /* NET_SKBUFF_DATA_USES_OFFSET */ 1309 1310 /* 1311 * Add data to an sk_buff 1312 */ 1313 extern unsigned char *skb_put(struct sk_buff *skb, unsigned int len); 1314 static inline unsigned char *__skb_put(struct sk_buff *skb, unsigned int len) 1315 { 1316 unsigned char *tmp = skb_tail_pointer(skb); 1317 SKB_LINEAR_ASSERT(skb); 1318 skb->tail += len; 1319 skb->len += len; 1320 return tmp; 1321 } 1322 1323 extern unsigned char *skb_push(struct sk_buff *skb, unsigned int len); 1324 static inline unsigned char *__skb_push(struct sk_buff *skb, unsigned int len) 1325 { 1326 skb->data -= len; 1327 skb->len += len; 1328 return skb->data; 1329 } 1330 1331 extern unsigned char *skb_pull(struct sk_buff *skb, unsigned int len); 1332 static inline unsigned char *__skb_pull(struct sk_buff *skb, unsigned int len) 1333 { 1334 skb->len -= len; 1335 BUG_ON(skb->len < skb->data_len); 1336 return skb->data += len; 1337 } 1338 1339 static inline unsigned char *skb_pull_inline(struct sk_buff *skb, unsigned int len) 1340 { 1341 return unlikely(len > skb->len) ? NULL : __skb_pull(skb, len); 1342 } 1343 1344 extern unsigned char *__pskb_pull_tail(struct sk_buff *skb, int delta); 1345 1346 static inline unsigned char *__pskb_pull(struct sk_buff *skb, unsigned int len) 1347 { 1348 if (len > skb_headlen(skb) && 1349 !__pskb_pull_tail(skb, len - skb_headlen(skb))) 1350 return NULL; 1351 skb->len -= len; 1352 return skb->data += len; 1353 } 1354 1355 static inline unsigned char *pskb_pull(struct sk_buff *skb, unsigned int len) 1356 { 1357 return unlikely(len > skb->len) ? NULL : __pskb_pull(skb, len); 1358 } 1359 1360 static inline int pskb_may_pull(struct sk_buff *skb, unsigned int len) 1361 { 1362 if (likely(len <= skb_headlen(skb))) 1363 return 1; 1364 if (unlikely(len > skb->len)) 1365 return 0; 1366 return __pskb_pull_tail(skb, len - skb_headlen(skb)) != NULL; 1367 } 1368 1369 /** 1370 * skb_headroom - bytes at buffer head 1371 * @skb: buffer to check 1372 * 1373 * Return the number of bytes of free space at the head of an &sk_buff. 1374 */ 1375 static inline unsigned int skb_headroom(const struct sk_buff *skb) 1376 { 1377 return skb->data - skb->head; 1378 } 1379 1380 /** 1381 * skb_tailroom - bytes at buffer end 1382 * @skb: buffer to check 1383 * 1384 * Return the number of bytes of free space at the tail of an sk_buff 1385 */ 1386 static inline int skb_tailroom(const struct sk_buff *skb) 1387 { 1388 return skb_is_nonlinear(skb) ? 0 : skb->end - skb->tail; 1389 } 1390 1391 /** 1392 * skb_availroom - bytes at buffer end 1393 * @skb: buffer to check 1394 * 1395 * Return the number of bytes of free space at the tail of an sk_buff 1396 * allocated by sk_stream_alloc() 1397 */ 1398 static inline int skb_availroom(const struct sk_buff *skb) 1399 { 1400 return skb_is_nonlinear(skb) ? 0 : skb->avail_size - skb->len; 1401 } 1402 1403 /** 1404 * skb_reserve - adjust headroom 1405 * @skb: buffer to alter 1406 * @len: bytes to move 1407 * 1408 * Increase the headroom of an empty &sk_buff by reducing the tail 1409 * room. This is only allowed for an empty buffer. 1410 */ 1411 static inline void skb_reserve(struct sk_buff *skb, int len) 1412 { 1413 skb->data += len; 1414 skb->tail += len; 1415 } 1416 1417 static inline void skb_reset_mac_len(struct sk_buff *skb) 1418 { 1419 skb->mac_len = skb->network_header - skb->mac_header; 1420 } 1421 1422 #ifdef NET_SKBUFF_DATA_USES_OFFSET 1423 static inline unsigned char *skb_transport_header(const struct sk_buff *skb) 1424 { 1425 return skb->head + skb->transport_header; 1426 } 1427 1428 static inline void skb_reset_transport_header(struct sk_buff *skb) 1429 { 1430 skb->transport_header = skb->data - skb->head; 1431 } 1432 1433 static inline void skb_set_transport_header(struct sk_buff *skb, 1434 const int offset) 1435 { 1436 skb_reset_transport_header(skb); 1437 skb->transport_header += offset; 1438 } 1439 1440 static inline unsigned char *skb_network_header(const struct sk_buff *skb) 1441 { 1442 return skb->head + skb->network_header; 1443 } 1444 1445 static inline void skb_reset_network_header(struct sk_buff *skb) 1446 { 1447 skb->network_header = skb->data - skb->head; 1448 } 1449 1450 static inline void skb_set_network_header(struct sk_buff *skb, const int offset) 1451 { 1452 skb_reset_network_header(skb); 1453 skb->network_header += offset; 1454 } 1455 1456 static inline unsigned char *skb_mac_header(const struct sk_buff *skb) 1457 { 1458 return skb->head + skb->mac_header; 1459 } 1460 1461 static inline int skb_mac_header_was_set(const struct sk_buff *skb) 1462 { 1463 return skb->mac_header != ~0U; 1464 } 1465 1466 static inline void skb_reset_mac_header(struct sk_buff *skb) 1467 { 1468 skb->mac_header = skb->data - skb->head; 1469 } 1470 1471 static inline void skb_set_mac_header(struct sk_buff *skb, const int offset) 1472 { 1473 skb_reset_mac_header(skb); 1474 skb->mac_header += offset; 1475 } 1476 1477 #else /* NET_SKBUFF_DATA_USES_OFFSET */ 1478 1479 static inline unsigned char *skb_transport_header(const struct sk_buff *skb) 1480 { 1481 return skb->transport_header; 1482 } 1483 1484 static inline void skb_reset_transport_header(struct sk_buff *skb) 1485 { 1486 skb->transport_header = skb->data; 1487 } 1488 1489 static inline void skb_set_transport_header(struct sk_buff *skb, 1490 const int offset) 1491 { 1492 skb->transport_header = skb->data + offset; 1493 } 1494 1495 static inline unsigned char *skb_network_header(const struct sk_buff *skb) 1496 { 1497 return skb->network_header; 1498 } 1499 1500 static inline void skb_reset_network_header(struct sk_buff *skb) 1501 { 1502 skb->network_header = skb->data; 1503 } 1504 1505 static inline void skb_set_network_header(struct sk_buff *skb, const int offset) 1506 { 1507 skb->network_header = skb->data + offset; 1508 } 1509 1510 static inline unsigned char *skb_mac_header(const struct sk_buff *skb) 1511 { 1512 return skb->mac_header; 1513 } 1514 1515 static inline int skb_mac_header_was_set(const struct sk_buff *skb) 1516 { 1517 return skb->mac_header != NULL; 1518 } 1519 1520 static inline void skb_reset_mac_header(struct sk_buff *skb) 1521 { 1522 skb->mac_header = skb->data; 1523 } 1524 1525 static inline void skb_set_mac_header(struct sk_buff *skb, const int offset) 1526 { 1527 skb->mac_header = skb->data + offset; 1528 } 1529 #endif /* NET_SKBUFF_DATA_USES_OFFSET */ 1530 1531 static inline void skb_mac_header_rebuild(struct sk_buff *skb) 1532 { 1533 if (skb_mac_header_was_set(skb)) { 1534 const unsigned char *old_mac = skb_mac_header(skb); 1535 1536 skb_set_mac_header(skb, -skb->mac_len); 1537 memmove(skb_mac_header(skb), old_mac, skb->mac_len); 1538 } 1539 } 1540 1541 static inline int skb_checksum_start_offset(const struct sk_buff *skb) 1542 { 1543 return skb->csum_start - skb_headroom(skb); 1544 } 1545 1546 static inline int skb_transport_offset(const struct sk_buff *skb) 1547 { 1548 return skb_transport_header(skb) - skb->data; 1549 } 1550 1551 static inline u32 skb_network_header_len(const struct sk_buff *skb) 1552 { 1553 return skb->transport_header - skb->network_header; 1554 } 1555 1556 static inline int skb_network_offset(const struct sk_buff *skb) 1557 { 1558 return skb_network_header(skb) - skb->data; 1559 } 1560 1561 static inline int pskb_network_may_pull(struct sk_buff *skb, unsigned int len) 1562 { 1563 return pskb_may_pull(skb, skb_network_offset(skb) + len); 1564 } 1565 1566 /* 1567 * CPUs often take a performance hit when accessing unaligned memory 1568 * locations. The actual performance hit varies, it can be small if the 1569 * hardware handles it or large if we have to take an exception and fix it 1570 * in software. 1571 * 1572 * Since an ethernet header is 14 bytes network drivers often end up with 1573 * the IP header at an unaligned offset. The IP header can be aligned by 1574 * shifting the start of the packet by 2 bytes. Drivers should do this 1575 * with: 1576 * 1577 * skb_reserve(skb, NET_IP_ALIGN); 1578 * 1579 * The downside to this alignment of the IP header is that the DMA is now 1580 * unaligned. On some architectures the cost of an unaligned DMA is high 1581 * and this cost outweighs the gains made by aligning the IP header. 1582 * 1583 * Since this trade off varies between architectures, we allow NET_IP_ALIGN 1584 * to be overridden. 1585 */ 1586 #ifndef NET_IP_ALIGN 1587 #define NET_IP_ALIGN 2 1588 #endif 1589 1590 /* 1591 * The networking layer reserves some headroom in skb data (via 1592 * dev_alloc_skb). This is used to avoid having to reallocate skb data when 1593 * the header has to grow. In the default case, if the header has to grow 1594 * 32 bytes or less we avoid the reallocation. 1595 * 1596 * Unfortunately this headroom changes the DMA alignment of the resulting 1597 * network packet. As for NET_IP_ALIGN, this unaligned DMA is expensive 1598 * on some architectures. An architecture can override this value, 1599 * perhaps setting it to a cacheline in size (since that will maintain 1600 * cacheline alignment of the DMA). It must be a power of 2. 1601 * 1602 * Various parts of the networking layer expect at least 32 bytes of 1603 * headroom, you should not reduce this. 1604 * 1605 * Using max(32, L1_CACHE_BYTES) makes sense (especially with RPS) 1606 * to reduce average number of cache lines per packet. 1607 * get_rps_cpus() for example only access one 64 bytes aligned block : 1608 * NET_IP_ALIGN(2) + ethernet_header(14) + IP_header(20/40) + ports(8) 1609 */ 1610 #ifndef NET_SKB_PAD 1611 #define NET_SKB_PAD max(32, L1_CACHE_BYTES) 1612 #endif 1613 1614 extern int ___pskb_trim(struct sk_buff *skb, unsigned int len); 1615 1616 static inline void __skb_trim(struct sk_buff *skb, unsigned int len) 1617 { 1618 if (unlikely(skb_is_nonlinear(skb))) { 1619 WARN_ON(1); 1620 return; 1621 } 1622 skb->len = len; 1623 skb_set_tail_pointer(skb, len); 1624 } 1625 1626 extern void skb_trim(struct sk_buff *skb, unsigned int len); 1627 1628 static inline int __pskb_trim(struct sk_buff *skb, unsigned int len) 1629 { 1630 if (skb->data_len) 1631 return ___pskb_trim(skb, len); 1632 __skb_trim(skb, len); 1633 return 0; 1634 } 1635 1636 static inline int pskb_trim(struct sk_buff *skb, unsigned int len) 1637 { 1638 return (len < skb->len) ? __pskb_trim(skb, len) : 0; 1639 } 1640 1641 /** 1642 * pskb_trim_unique - remove end from a paged unique (not cloned) buffer 1643 * @skb: buffer to alter 1644 * @len: new length 1645 * 1646 * This is identical to pskb_trim except that the caller knows that 1647 * the skb is not cloned so we should never get an error due to out- 1648 * of-memory. 1649 */ 1650 static inline void pskb_trim_unique(struct sk_buff *skb, unsigned int len) 1651 { 1652 int err = pskb_trim(skb, len); 1653 BUG_ON(err); 1654 } 1655 1656 /** 1657 * skb_orphan - orphan a buffer 1658 * @skb: buffer to orphan 1659 * 1660 * If a buffer currently has an owner then we call the owner's 1661 * destructor function and make the @skb unowned. The buffer continues 1662 * to exist but is no longer charged to its former owner. 1663 */ 1664 static inline void skb_orphan(struct sk_buff *skb) 1665 { 1666 if (skb->destructor) 1667 skb->destructor(skb); 1668 skb->destructor = NULL; 1669 skb->sk = NULL; 1670 } 1671 1672 /** 1673 * __skb_queue_purge - empty a list 1674 * @list: list to empty 1675 * 1676 * Delete all buffers on an &sk_buff list. Each buffer is removed from 1677 * the list and one reference dropped. This function does not take the 1678 * list lock and the caller must hold the relevant locks to use it. 1679 */ 1680 extern void skb_queue_purge(struct sk_buff_head *list); 1681 static inline void __skb_queue_purge(struct sk_buff_head *list) 1682 { 1683 struct sk_buff *skb; 1684 while ((skb = __skb_dequeue(list)) != NULL) 1685 kfree_skb(skb); 1686 } 1687 1688 extern void *netdev_alloc_frag(unsigned int fragsz); 1689 1690 extern struct sk_buff *__netdev_alloc_skb(struct net_device *dev, 1691 unsigned int length, 1692 gfp_t gfp_mask); 1693 1694 /** 1695 * netdev_alloc_skb - allocate an skbuff for rx on a specific device 1696 * @dev: network device to receive on 1697 * @length: length to allocate 1698 * 1699 * Allocate a new &sk_buff and assign it a usage count of one. The 1700 * buffer has unspecified headroom built in. Users should allocate 1701 * the headroom they think they need without accounting for the 1702 * built in space. The built in space is used for optimisations. 1703 * 1704 * %NULL is returned if there is no free memory. Although this function 1705 * allocates memory it can be called from an interrupt. 1706 */ 1707 static inline struct sk_buff *netdev_alloc_skb(struct net_device *dev, 1708 unsigned int length) 1709 { 1710 return __netdev_alloc_skb(dev, length, GFP_ATOMIC); 1711 } 1712 1713 /* legacy helper around __netdev_alloc_skb() */ 1714 static inline struct sk_buff *__dev_alloc_skb(unsigned int length, 1715 gfp_t gfp_mask) 1716 { 1717 return __netdev_alloc_skb(NULL, length, gfp_mask); 1718 } 1719 1720 /* legacy helper around netdev_alloc_skb() */ 1721 static inline struct sk_buff *dev_alloc_skb(unsigned int length) 1722 { 1723 return netdev_alloc_skb(NULL, length); 1724 } 1725 1726 1727 static inline struct sk_buff *__netdev_alloc_skb_ip_align(struct net_device *dev, 1728 unsigned int length, gfp_t gfp) 1729 { 1730 struct sk_buff *skb = __netdev_alloc_skb(dev, length + NET_IP_ALIGN, gfp); 1731 1732 if (NET_IP_ALIGN && skb) 1733 skb_reserve(skb, NET_IP_ALIGN); 1734 return skb; 1735 } 1736 1737 static inline struct sk_buff *netdev_alloc_skb_ip_align(struct net_device *dev, 1738 unsigned int length) 1739 { 1740 return __netdev_alloc_skb_ip_align(dev, length, GFP_ATOMIC); 1741 } 1742 1743 /** 1744 * skb_frag_page - retrieve the page refered to by a paged fragment 1745 * @frag: the paged fragment 1746 * 1747 * Returns the &struct page associated with @frag. 1748 */ 1749 static inline struct page *skb_frag_page(const skb_frag_t *frag) 1750 { 1751 return frag->page.p; 1752 } 1753 1754 /** 1755 * __skb_frag_ref - take an addition reference on a paged fragment. 1756 * @frag: the paged fragment 1757 * 1758 * Takes an additional reference on the paged fragment @frag. 1759 */ 1760 static inline void __skb_frag_ref(skb_frag_t *frag) 1761 { 1762 get_page(skb_frag_page(frag)); 1763 } 1764 1765 /** 1766 * skb_frag_ref - take an addition reference on a paged fragment of an skb. 1767 * @skb: the buffer 1768 * @f: the fragment offset. 1769 * 1770 * Takes an additional reference on the @f'th paged fragment of @skb. 1771 */ 1772 static inline void skb_frag_ref(struct sk_buff *skb, int f) 1773 { 1774 __skb_frag_ref(&skb_shinfo(skb)->frags[f]); 1775 } 1776 1777 /** 1778 * __skb_frag_unref - release a reference on a paged fragment. 1779 * @frag: the paged fragment 1780 * 1781 * Releases a reference on the paged fragment @frag. 1782 */ 1783 static inline void __skb_frag_unref(skb_frag_t *frag) 1784 { 1785 put_page(skb_frag_page(frag)); 1786 } 1787 1788 /** 1789 * skb_frag_unref - release a reference on a paged fragment of an skb. 1790 * @skb: the buffer 1791 * @f: the fragment offset 1792 * 1793 * Releases a reference on the @f'th paged fragment of @skb. 1794 */ 1795 static inline void skb_frag_unref(struct sk_buff *skb, int f) 1796 { 1797 __skb_frag_unref(&skb_shinfo(skb)->frags[f]); 1798 } 1799 1800 /** 1801 * skb_frag_address - gets the address of the data contained in a paged fragment 1802 * @frag: the paged fragment buffer 1803 * 1804 * Returns the address of the data within @frag. The page must already 1805 * be mapped. 1806 */ 1807 static inline void *skb_frag_address(const skb_frag_t *frag) 1808 { 1809 return page_address(skb_frag_page(frag)) + frag->page_offset; 1810 } 1811 1812 /** 1813 * skb_frag_address_safe - gets the address of the data contained in a paged fragment 1814 * @frag: the paged fragment buffer 1815 * 1816 * Returns the address of the data within @frag. Checks that the page 1817 * is mapped and returns %NULL otherwise. 1818 */ 1819 static inline void *skb_frag_address_safe(const skb_frag_t *frag) 1820 { 1821 void *ptr = page_address(skb_frag_page(frag)); 1822 if (unlikely(!ptr)) 1823 return NULL; 1824 1825 return ptr + frag->page_offset; 1826 } 1827 1828 /** 1829 * __skb_frag_set_page - sets the page contained in a paged fragment 1830 * @frag: the paged fragment 1831 * @page: the page to set 1832 * 1833 * Sets the fragment @frag to contain @page. 1834 */ 1835 static inline void __skb_frag_set_page(skb_frag_t *frag, struct page *page) 1836 { 1837 frag->page.p = page; 1838 } 1839 1840 /** 1841 * skb_frag_set_page - sets the page contained in a paged fragment of an skb 1842 * @skb: the buffer 1843 * @f: the fragment offset 1844 * @page: the page to set 1845 * 1846 * Sets the @f'th fragment of @skb to contain @page. 1847 */ 1848 static inline void skb_frag_set_page(struct sk_buff *skb, int f, 1849 struct page *page) 1850 { 1851 __skb_frag_set_page(&skb_shinfo(skb)->frags[f], page); 1852 } 1853 1854 /** 1855 * skb_frag_dma_map - maps a paged fragment via the DMA API 1856 * @dev: the device to map the fragment to 1857 * @frag: the paged fragment to map 1858 * @offset: the offset within the fragment (starting at the 1859 * fragment's own offset) 1860 * @size: the number of bytes to map 1861 * @dir: the direction of the mapping (%PCI_DMA_*) 1862 * 1863 * Maps the page associated with @frag to @device. 1864 */ 1865 static inline dma_addr_t skb_frag_dma_map(struct device *dev, 1866 const skb_frag_t *frag, 1867 size_t offset, size_t size, 1868 enum dma_data_direction dir) 1869 { 1870 return dma_map_page(dev, skb_frag_page(frag), 1871 frag->page_offset + offset, size, dir); 1872 } 1873 1874 static inline struct sk_buff *pskb_copy(struct sk_buff *skb, 1875 gfp_t gfp_mask) 1876 { 1877 return __pskb_copy(skb, skb_headroom(skb), gfp_mask); 1878 } 1879 1880 /** 1881 * skb_clone_writable - is the header of a clone writable 1882 * @skb: buffer to check 1883 * @len: length up to which to write 1884 * 1885 * Returns true if modifying the header part of the cloned buffer 1886 * does not requires the data to be copied. 1887 */ 1888 static inline int skb_clone_writable(const struct sk_buff *skb, unsigned int len) 1889 { 1890 return !skb_header_cloned(skb) && 1891 skb_headroom(skb) + len <= skb->hdr_len; 1892 } 1893 1894 static inline int __skb_cow(struct sk_buff *skb, unsigned int headroom, 1895 int cloned) 1896 { 1897 int delta = 0; 1898 1899 if (headroom < NET_SKB_PAD) 1900 headroom = NET_SKB_PAD; 1901 if (headroom > skb_headroom(skb)) 1902 delta = headroom - skb_headroom(skb); 1903 1904 if (delta || cloned) 1905 return pskb_expand_head(skb, ALIGN(delta, NET_SKB_PAD), 0, 1906 GFP_ATOMIC); 1907 return 0; 1908 } 1909 1910 /** 1911 * skb_cow - copy header of skb when it is required 1912 * @skb: buffer to cow 1913 * @headroom: needed headroom 1914 * 1915 * If the skb passed lacks sufficient headroom or its data part 1916 * is shared, data is reallocated. If reallocation fails, an error 1917 * is returned and original skb is not changed. 1918 * 1919 * The result is skb with writable area skb->head...skb->tail 1920 * and at least @headroom of space at head. 1921 */ 1922 static inline int skb_cow(struct sk_buff *skb, unsigned int headroom) 1923 { 1924 return __skb_cow(skb, headroom, skb_cloned(skb)); 1925 } 1926 1927 /** 1928 * skb_cow_head - skb_cow but only making the head writable 1929 * @skb: buffer to cow 1930 * @headroom: needed headroom 1931 * 1932 * This function is identical to skb_cow except that we replace the 1933 * skb_cloned check by skb_header_cloned. It should be used when 1934 * you only need to push on some header and do not need to modify 1935 * the data. 1936 */ 1937 static inline int skb_cow_head(struct sk_buff *skb, unsigned int headroom) 1938 { 1939 return __skb_cow(skb, headroom, skb_header_cloned(skb)); 1940 } 1941 1942 /** 1943 * skb_padto - pad an skbuff up to a minimal size 1944 * @skb: buffer to pad 1945 * @len: minimal length 1946 * 1947 * Pads up a buffer to ensure the trailing bytes exist and are 1948 * blanked. If the buffer already contains sufficient data it 1949 * is untouched. Otherwise it is extended. Returns zero on 1950 * success. The skb is freed on error. 1951 */ 1952 1953 static inline int skb_padto(struct sk_buff *skb, unsigned int len) 1954 { 1955 unsigned int size = skb->len; 1956 if (likely(size >= len)) 1957 return 0; 1958 return skb_pad(skb, len - size); 1959 } 1960 1961 static inline int skb_add_data(struct sk_buff *skb, 1962 char __user *from, int copy) 1963 { 1964 const int off = skb->len; 1965 1966 if (skb->ip_summed == CHECKSUM_NONE) { 1967 int err = 0; 1968 __wsum csum = csum_and_copy_from_user(from, skb_put(skb, copy), 1969 copy, 0, &err); 1970 if (!err) { 1971 skb->csum = csum_block_add(skb->csum, csum, off); 1972 return 0; 1973 } 1974 } else if (!copy_from_user(skb_put(skb, copy), from, copy)) 1975 return 0; 1976 1977 __skb_trim(skb, off); 1978 return -EFAULT; 1979 } 1980 1981 static inline bool skb_can_coalesce(struct sk_buff *skb, int i, 1982 const struct page *page, int off) 1983 { 1984 if (i) { 1985 const struct skb_frag_struct *frag = &skb_shinfo(skb)->frags[i - 1]; 1986 1987 return page == skb_frag_page(frag) && 1988 off == frag->page_offset + skb_frag_size(frag); 1989 } 1990 return false; 1991 } 1992 1993 static inline int __skb_linearize(struct sk_buff *skb) 1994 { 1995 return __pskb_pull_tail(skb, skb->data_len) ? 0 : -ENOMEM; 1996 } 1997 1998 /** 1999 * skb_linearize - convert paged skb to linear one 2000 * @skb: buffer to linarize 2001 * 2002 * If there is no free memory -ENOMEM is returned, otherwise zero 2003 * is returned and the old skb data released. 2004 */ 2005 static inline int skb_linearize(struct sk_buff *skb) 2006 { 2007 return skb_is_nonlinear(skb) ? __skb_linearize(skb) : 0; 2008 } 2009 2010 /** 2011 * skb_linearize_cow - make sure skb is linear and writable 2012 * @skb: buffer to process 2013 * 2014 * If there is no free memory -ENOMEM is returned, otherwise zero 2015 * is returned and the old skb data released. 2016 */ 2017 static inline int skb_linearize_cow(struct sk_buff *skb) 2018 { 2019 return skb_is_nonlinear(skb) || skb_cloned(skb) ? 2020 __skb_linearize(skb) : 0; 2021 } 2022 2023 /** 2024 * skb_postpull_rcsum - update checksum for received skb after pull 2025 * @skb: buffer to update 2026 * @start: start of data before pull 2027 * @len: length of data pulled 2028 * 2029 * After doing a pull on a received packet, you need to call this to 2030 * update the CHECKSUM_COMPLETE checksum, or set ip_summed to 2031 * CHECKSUM_NONE so that it can be recomputed from scratch. 2032 */ 2033 2034 static inline void skb_postpull_rcsum(struct sk_buff *skb, 2035 const void *start, unsigned int len) 2036 { 2037 if (skb->ip_summed == CHECKSUM_COMPLETE) 2038 skb->csum = csum_sub(skb->csum, csum_partial(start, len, 0)); 2039 } 2040 2041 unsigned char *skb_pull_rcsum(struct sk_buff *skb, unsigned int len); 2042 2043 /** 2044 * pskb_trim_rcsum - trim received skb and update checksum 2045 * @skb: buffer to trim 2046 * @len: new length 2047 * 2048 * This is exactly the same as pskb_trim except that it ensures the 2049 * checksum of received packets are still valid after the operation. 2050 */ 2051 2052 static inline int pskb_trim_rcsum(struct sk_buff *skb, unsigned int len) 2053 { 2054 if (likely(len >= skb->len)) 2055 return 0; 2056 if (skb->ip_summed == CHECKSUM_COMPLETE) 2057 skb->ip_summed = CHECKSUM_NONE; 2058 return __pskb_trim(skb, len); 2059 } 2060 2061 #define skb_queue_walk(queue, skb) \ 2062 for (skb = (queue)->next; \ 2063 skb != (struct sk_buff *)(queue); \ 2064 skb = skb->next) 2065 2066 #define skb_queue_walk_safe(queue, skb, tmp) \ 2067 for (skb = (queue)->next, tmp = skb->next; \ 2068 skb != (struct sk_buff *)(queue); \ 2069 skb = tmp, tmp = skb->next) 2070 2071 #define skb_queue_walk_from(queue, skb) \ 2072 for (; skb != (struct sk_buff *)(queue); \ 2073 skb = skb->next) 2074 2075 #define skb_queue_walk_from_safe(queue, skb, tmp) \ 2076 for (tmp = skb->next; \ 2077 skb != (struct sk_buff *)(queue); \ 2078 skb = tmp, tmp = skb->next) 2079 2080 #define skb_queue_reverse_walk(queue, skb) \ 2081 for (skb = (queue)->prev; \ 2082 skb != (struct sk_buff *)(queue); \ 2083 skb = skb->prev) 2084 2085 #define skb_queue_reverse_walk_safe(queue, skb, tmp) \ 2086 for (skb = (queue)->prev, tmp = skb->prev; \ 2087 skb != (struct sk_buff *)(queue); \ 2088 skb = tmp, tmp = skb->prev) 2089 2090 #define skb_queue_reverse_walk_from_safe(queue, skb, tmp) \ 2091 for (tmp = skb->prev; \ 2092 skb != (struct sk_buff *)(queue); \ 2093 skb = tmp, tmp = skb->prev) 2094 2095 static inline bool skb_has_frag_list(const struct sk_buff *skb) 2096 { 2097 return skb_shinfo(skb)->frag_list != NULL; 2098 } 2099 2100 static inline void skb_frag_list_init(struct sk_buff *skb) 2101 { 2102 skb_shinfo(skb)->frag_list = NULL; 2103 } 2104 2105 static inline void skb_frag_add_head(struct sk_buff *skb, struct sk_buff *frag) 2106 { 2107 frag->next = skb_shinfo(skb)->frag_list; 2108 skb_shinfo(skb)->frag_list = frag; 2109 } 2110 2111 #define skb_walk_frags(skb, iter) \ 2112 for (iter = skb_shinfo(skb)->frag_list; iter; iter = iter->next) 2113 2114 extern struct sk_buff *__skb_recv_datagram(struct sock *sk, unsigned flags, 2115 int *peeked, int *off, int *err); 2116 extern struct sk_buff *skb_recv_datagram(struct sock *sk, unsigned flags, 2117 int noblock, int *err); 2118 extern unsigned int datagram_poll(struct file *file, struct socket *sock, 2119 struct poll_table_struct *wait); 2120 extern int skb_copy_datagram_iovec(const struct sk_buff *from, 2121 int offset, struct iovec *to, 2122 int size); 2123 extern int skb_copy_and_csum_datagram_iovec(struct sk_buff *skb, 2124 int hlen, 2125 struct iovec *iov); 2126 extern int skb_copy_datagram_from_iovec(struct sk_buff *skb, 2127 int offset, 2128 const struct iovec *from, 2129 int from_offset, 2130 int len); 2131 extern int skb_copy_datagram_const_iovec(const struct sk_buff *from, 2132 int offset, 2133 const struct iovec *to, 2134 int to_offset, 2135 int size); 2136 extern void skb_free_datagram(struct sock *sk, struct sk_buff *skb); 2137 extern void skb_free_datagram_locked(struct sock *sk, 2138 struct sk_buff *skb); 2139 extern int skb_kill_datagram(struct sock *sk, struct sk_buff *skb, 2140 unsigned int flags); 2141 extern __wsum skb_checksum(const struct sk_buff *skb, int offset, 2142 int len, __wsum csum); 2143 extern int skb_copy_bits(const struct sk_buff *skb, int offset, 2144 void *to, int len); 2145 extern int skb_store_bits(struct sk_buff *skb, int offset, 2146 const void *from, int len); 2147 extern __wsum skb_copy_and_csum_bits(const struct sk_buff *skb, 2148 int offset, u8 *to, int len, 2149 __wsum csum); 2150 extern int skb_splice_bits(struct sk_buff *skb, 2151 unsigned int offset, 2152 struct pipe_inode_info *pipe, 2153 unsigned int len, 2154 unsigned int flags); 2155 extern void skb_copy_and_csum_dev(const struct sk_buff *skb, u8 *to); 2156 extern void skb_split(struct sk_buff *skb, 2157 struct sk_buff *skb1, const u32 len); 2158 extern int skb_shift(struct sk_buff *tgt, struct sk_buff *skb, 2159 int shiftlen); 2160 2161 extern struct sk_buff *skb_segment(struct sk_buff *skb, 2162 netdev_features_t features); 2163 2164 static inline void *skb_header_pointer(const struct sk_buff *skb, int offset, 2165 int len, void *buffer) 2166 { 2167 int hlen = skb_headlen(skb); 2168 2169 if (hlen - offset >= len) 2170 return skb->data + offset; 2171 2172 if (skb_copy_bits(skb, offset, buffer, len) < 0) 2173 return NULL; 2174 2175 return buffer; 2176 } 2177 2178 static inline void skb_copy_from_linear_data(const struct sk_buff *skb, 2179 void *to, 2180 const unsigned int len) 2181 { 2182 memcpy(to, skb->data, len); 2183 } 2184 2185 static inline void skb_copy_from_linear_data_offset(const struct sk_buff *skb, 2186 const int offset, void *to, 2187 const unsigned int len) 2188 { 2189 memcpy(to, skb->data + offset, len); 2190 } 2191 2192 static inline void skb_copy_to_linear_data(struct sk_buff *skb, 2193 const void *from, 2194 const unsigned int len) 2195 { 2196 memcpy(skb->data, from, len); 2197 } 2198 2199 static inline void skb_copy_to_linear_data_offset(struct sk_buff *skb, 2200 const int offset, 2201 const void *from, 2202 const unsigned int len) 2203 { 2204 memcpy(skb->data + offset, from, len); 2205 } 2206 2207 extern void skb_init(void); 2208 2209 static inline ktime_t skb_get_ktime(const struct sk_buff *skb) 2210 { 2211 return skb->tstamp; 2212 } 2213 2214 /** 2215 * skb_get_timestamp - get timestamp from a skb 2216 * @skb: skb to get stamp from 2217 * @stamp: pointer to struct timeval to store stamp in 2218 * 2219 * Timestamps are stored in the skb as offsets to a base timestamp. 2220 * This function converts the offset back to a struct timeval and stores 2221 * it in stamp. 2222 */ 2223 static inline void skb_get_timestamp(const struct sk_buff *skb, 2224 struct timeval *stamp) 2225 { 2226 *stamp = ktime_to_timeval(skb->tstamp); 2227 } 2228 2229 static inline void skb_get_timestampns(const struct sk_buff *skb, 2230 struct timespec *stamp) 2231 { 2232 *stamp = ktime_to_timespec(skb->tstamp); 2233 } 2234 2235 static inline void __net_timestamp(struct sk_buff *skb) 2236 { 2237 skb->tstamp = ktime_get_real(); 2238 } 2239 2240 static inline ktime_t net_timedelta(ktime_t t) 2241 { 2242 return ktime_sub(ktime_get_real(), t); 2243 } 2244 2245 static inline ktime_t net_invalid_timestamp(void) 2246 { 2247 return ktime_set(0, 0); 2248 } 2249 2250 extern void skb_timestamping_init(void); 2251 2252 #ifdef CONFIG_NETWORK_PHY_TIMESTAMPING 2253 2254 extern void skb_clone_tx_timestamp(struct sk_buff *skb); 2255 extern bool skb_defer_rx_timestamp(struct sk_buff *skb); 2256 2257 #else /* CONFIG_NETWORK_PHY_TIMESTAMPING */ 2258 2259 static inline void skb_clone_tx_timestamp(struct sk_buff *skb) 2260 { 2261 } 2262 2263 static inline bool skb_defer_rx_timestamp(struct sk_buff *skb) 2264 { 2265 return false; 2266 } 2267 2268 #endif /* !CONFIG_NETWORK_PHY_TIMESTAMPING */ 2269 2270 /** 2271 * skb_complete_tx_timestamp() - deliver cloned skb with tx timestamps 2272 * 2273 * PHY drivers may accept clones of transmitted packets for 2274 * timestamping via their phy_driver.txtstamp method. These drivers 2275 * must call this function to return the skb back to the stack, with 2276 * or without a timestamp. 2277 * 2278 * @skb: clone of the the original outgoing packet 2279 * @hwtstamps: hardware time stamps, may be NULL if not available 2280 * 2281 */ 2282 void skb_complete_tx_timestamp(struct sk_buff *skb, 2283 struct skb_shared_hwtstamps *hwtstamps); 2284 2285 /** 2286 * skb_tstamp_tx - queue clone of skb with send time stamps 2287 * @orig_skb: the original outgoing packet 2288 * @hwtstamps: hardware time stamps, may be NULL if not available 2289 * 2290 * If the skb has a socket associated, then this function clones the 2291 * skb (thus sharing the actual data and optional structures), stores 2292 * the optional hardware time stamping information (if non NULL) or 2293 * generates a software time stamp (otherwise), then queues the clone 2294 * to the error queue of the socket. Errors are silently ignored. 2295 */ 2296 extern void skb_tstamp_tx(struct sk_buff *orig_skb, 2297 struct skb_shared_hwtstamps *hwtstamps); 2298 2299 static inline void sw_tx_timestamp(struct sk_buff *skb) 2300 { 2301 if (skb_shinfo(skb)->tx_flags & SKBTX_SW_TSTAMP && 2302 !(skb_shinfo(skb)->tx_flags & SKBTX_IN_PROGRESS)) 2303 skb_tstamp_tx(skb, NULL); 2304 } 2305 2306 /** 2307 * skb_tx_timestamp() - Driver hook for transmit timestamping 2308 * 2309 * Ethernet MAC Drivers should call this function in their hard_xmit() 2310 * function immediately before giving the sk_buff to the MAC hardware. 2311 * 2312 * @skb: A socket buffer. 2313 */ 2314 static inline void skb_tx_timestamp(struct sk_buff *skb) 2315 { 2316 skb_clone_tx_timestamp(skb); 2317 sw_tx_timestamp(skb); 2318 } 2319 2320 /** 2321 * skb_complete_wifi_ack - deliver skb with wifi status 2322 * 2323 * @skb: the original outgoing packet 2324 * @acked: ack status 2325 * 2326 */ 2327 void skb_complete_wifi_ack(struct sk_buff *skb, bool acked); 2328 2329 extern __sum16 __skb_checksum_complete_head(struct sk_buff *skb, int len); 2330 extern __sum16 __skb_checksum_complete(struct sk_buff *skb); 2331 2332 static inline int skb_csum_unnecessary(const struct sk_buff *skb) 2333 { 2334 return skb->ip_summed & CHECKSUM_UNNECESSARY; 2335 } 2336 2337 /** 2338 * skb_checksum_complete - Calculate checksum of an entire packet 2339 * @skb: packet to process 2340 * 2341 * This function calculates the checksum over the entire packet plus 2342 * the value of skb->csum. The latter can be used to supply the 2343 * checksum of a pseudo header as used by TCP/UDP. It returns the 2344 * checksum. 2345 * 2346 * For protocols that contain complete checksums such as ICMP/TCP/UDP, 2347 * this function can be used to verify that checksum on received 2348 * packets. In that case the function should return zero if the 2349 * checksum is correct. In particular, this function will return zero 2350 * if skb->ip_summed is CHECKSUM_UNNECESSARY which indicates that the 2351 * hardware has already verified the correctness of the checksum. 2352 */ 2353 static inline __sum16 skb_checksum_complete(struct sk_buff *skb) 2354 { 2355 return skb_csum_unnecessary(skb) ? 2356 0 : __skb_checksum_complete(skb); 2357 } 2358 2359 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE) 2360 extern void nf_conntrack_destroy(struct nf_conntrack *nfct); 2361 static inline void nf_conntrack_put(struct nf_conntrack *nfct) 2362 { 2363 if (nfct && atomic_dec_and_test(&nfct->use)) 2364 nf_conntrack_destroy(nfct); 2365 } 2366 static inline void nf_conntrack_get(struct nf_conntrack *nfct) 2367 { 2368 if (nfct) 2369 atomic_inc(&nfct->use); 2370 } 2371 #endif 2372 #ifdef NET_SKBUFF_NF_DEFRAG_NEEDED 2373 static inline void nf_conntrack_get_reasm(struct sk_buff *skb) 2374 { 2375 if (skb) 2376 atomic_inc(&skb->users); 2377 } 2378 static inline void nf_conntrack_put_reasm(struct sk_buff *skb) 2379 { 2380 if (skb) 2381 kfree_skb(skb); 2382 } 2383 #endif 2384 #ifdef CONFIG_BRIDGE_NETFILTER 2385 static inline void nf_bridge_put(struct nf_bridge_info *nf_bridge) 2386 { 2387 if (nf_bridge && atomic_dec_and_test(&nf_bridge->use)) 2388 kfree(nf_bridge); 2389 } 2390 static inline void nf_bridge_get(struct nf_bridge_info *nf_bridge) 2391 { 2392 if (nf_bridge) 2393 atomic_inc(&nf_bridge->use); 2394 } 2395 #endif /* CONFIG_BRIDGE_NETFILTER */ 2396 static inline void nf_reset(struct sk_buff *skb) 2397 { 2398 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE) 2399 nf_conntrack_put(skb->nfct); 2400 skb->nfct = NULL; 2401 #endif 2402 #ifdef NET_SKBUFF_NF_DEFRAG_NEEDED 2403 nf_conntrack_put_reasm(skb->nfct_reasm); 2404 skb->nfct_reasm = NULL; 2405 #endif 2406 #ifdef CONFIG_BRIDGE_NETFILTER 2407 nf_bridge_put(skb->nf_bridge); 2408 skb->nf_bridge = NULL; 2409 #endif 2410 } 2411 2412 /* Note: This doesn't put any conntrack and bridge info in dst. */ 2413 static inline void __nf_copy(struct sk_buff *dst, const struct sk_buff *src) 2414 { 2415 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE) 2416 dst->nfct = src->nfct; 2417 nf_conntrack_get(src->nfct); 2418 dst->nfctinfo = src->nfctinfo; 2419 #endif 2420 #ifdef NET_SKBUFF_NF_DEFRAG_NEEDED 2421 dst->nfct_reasm = src->nfct_reasm; 2422 nf_conntrack_get_reasm(src->nfct_reasm); 2423 #endif 2424 #ifdef CONFIG_BRIDGE_NETFILTER 2425 dst->nf_bridge = src->nf_bridge; 2426 nf_bridge_get(src->nf_bridge); 2427 #endif 2428 } 2429 2430 static inline void nf_copy(struct sk_buff *dst, const struct sk_buff *src) 2431 { 2432 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE) 2433 nf_conntrack_put(dst->nfct); 2434 #endif 2435 #ifdef NET_SKBUFF_NF_DEFRAG_NEEDED 2436 nf_conntrack_put_reasm(dst->nfct_reasm); 2437 #endif 2438 #ifdef CONFIG_BRIDGE_NETFILTER 2439 nf_bridge_put(dst->nf_bridge); 2440 #endif 2441 __nf_copy(dst, src); 2442 } 2443 2444 #ifdef CONFIG_NETWORK_SECMARK 2445 static inline void skb_copy_secmark(struct sk_buff *to, const struct sk_buff *from) 2446 { 2447 to->secmark = from->secmark; 2448 } 2449 2450 static inline void skb_init_secmark(struct sk_buff *skb) 2451 { 2452 skb->secmark = 0; 2453 } 2454 #else 2455 static inline void skb_copy_secmark(struct sk_buff *to, const struct sk_buff *from) 2456 { } 2457 2458 static inline void skb_init_secmark(struct sk_buff *skb) 2459 { } 2460 #endif 2461 2462 static inline void skb_set_queue_mapping(struct sk_buff *skb, u16 queue_mapping) 2463 { 2464 skb->queue_mapping = queue_mapping; 2465 } 2466 2467 static inline u16 skb_get_queue_mapping(const struct sk_buff *skb) 2468 { 2469 return skb->queue_mapping; 2470 } 2471 2472 static inline void skb_copy_queue_mapping(struct sk_buff *to, const struct sk_buff *from) 2473 { 2474 to->queue_mapping = from->queue_mapping; 2475 } 2476 2477 static inline void skb_record_rx_queue(struct sk_buff *skb, u16 rx_queue) 2478 { 2479 skb->queue_mapping = rx_queue + 1; 2480 } 2481 2482 static inline u16 skb_get_rx_queue(const struct sk_buff *skb) 2483 { 2484 return skb->queue_mapping - 1; 2485 } 2486 2487 static inline bool skb_rx_queue_recorded(const struct sk_buff *skb) 2488 { 2489 return skb->queue_mapping != 0; 2490 } 2491 2492 extern u16 __skb_tx_hash(const struct net_device *dev, 2493 const struct sk_buff *skb, 2494 unsigned int num_tx_queues); 2495 2496 #ifdef CONFIG_XFRM 2497 static inline struct sec_path *skb_sec_path(struct sk_buff *skb) 2498 { 2499 return skb->sp; 2500 } 2501 #else 2502 static inline struct sec_path *skb_sec_path(struct sk_buff *skb) 2503 { 2504 return NULL; 2505 } 2506 #endif 2507 2508 static inline bool skb_is_gso(const struct sk_buff *skb) 2509 { 2510 return skb_shinfo(skb)->gso_size; 2511 } 2512 2513 static inline bool skb_is_gso_v6(const struct sk_buff *skb) 2514 { 2515 return skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6; 2516 } 2517 2518 extern void __skb_warn_lro_forwarding(const struct sk_buff *skb); 2519 2520 static inline bool skb_warn_if_lro(const struct sk_buff *skb) 2521 { 2522 /* LRO sets gso_size but not gso_type, whereas if GSO is really 2523 * wanted then gso_type will be set. */ 2524 const struct skb_shared_info *shinfo = skb_shinfo(skb); 2525 2526 if (skb_is_nonlinear(skb) && shinfo->gso_size != 0 && 2527 unlikely(shinfo->gso_type == 0)) { 2528 __skb_warn_lro_forwarding(skb); 2529 return true; 2530 } 2531 return false; 2532 } 2533 2534 static inline void skb_forward_csum(struct sk_buff *skb) 2535 { 2536 /* Unfortunately we don't support this one. Any brave souls? */ 2537 if (skb->ip_summed == CHECKSUM_COMPLETE) 2538 skb->ip_summed = CHECKSUM_NONE; 2539 } 2540 2541 /** 2542 * skb_checksum_none_assert - make sure skb ip_summed is CHECKSUM_NONE 2543 * @skb: skb to check 2544 * 2545 * fresh skbs have their ip_summed set to CHECKSUM_NONE. 2546 * Instead of forcing ip_summed to CHECKSUM_NONE, we can 2547 * use this helper, to document places where we make this assertion. 2548 */ 2549 static inline void skb_checksum_none_assert(const struct sk_buff *skb) 2550 { 2551 #ifdef DEBUG 2552 BUG_ON(skb->ip_summed != CHECKSUM_NONE); 2553 #endif 2554 } 2555 2556 bool skb_partial_csum_set(struct sk_buff *skb, u16 start, u16 off); 2557 2558 static inline bool skb_is_recycleable(const struct sk_buff *skb, int skb_size) 2559 { 2560 if (irqs_disabled()) 2561 return false; 2562 2563 if (skb_shinfo(skb)->tx_flags & SKBTX_DEV_ZEROCOPY) 2564 return false; 2565 2566 if (skb_is_nonlinear(skb) || skb->fclone != SKB_FCLONE_UNAVAILABLE) 2567 return false; 2568 2569 skb_size = SKB_DATA_ALIGN(skb_size + NET_SKB_PAD); 2570 if (skb_end_offset(skb) < skb_size) 2571 return false; 2572 2573 if (skb_shared(skb) || skb_cloned(skb)) 2574 return false; 2575 2576 return true; 2577 } 2578 2579 /** 2580 * skb_head_is_locked - Determine if the skb->head is locked down 2581 * @skb: skb to check 2582 * 2583 * The head on skbs build around a head frag can be removed if they are 2584 * not cloned. This function returns true if the skb head is locked down 2585 * due to either being allocated via kmalloc, or by being a clone with 2586 * multiple references to the head. 2587 */ 2588 static inline bool skb_head_is_locked(const struct sk_buff *skb) 2589 { 2590 return !skb->head_frag || skb_cloned(skb); 2591 } 2592 #endif /* __KERNEL__ */ 2593 #endif /* _LINUX_SKBUFF_H */ 2594