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