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