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