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