1 /* 2 * INET An implementation of the TCP/IP protocol suite for the LINUX 3 * operating system. INET is implemented using the BSD Socket 4 * interface as the means of communication with the user level. 5 * 6 * Definitions for the TCP module. 7 * 8 * Version: @(#)tcp.h 1.0.5 05/23/93 9 * 10 * Authors: Ross Biro 11 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG> 12 * 13 * This program is free software; you can redistribute it and/or 14 * modify it under the terms of the GNU General Public License 15 * as published by the Free Software Foundation; either version 16 * 2 of the License, or (at your option) any later version. 17 */ 18 #ifndef _TCP_H 19 #define _TCP_H 20 21 #define TCP_DEBUG 1 22 #define FASTRETRANS_DEBUG 1 23 24 /* Cancel timers, when they are not required. */ 25 #undef TCP_CLEAR_TIMERS 26 27 #include <linux/config.h> 28 #include <linux/list.h> 29 #include <linux/tcp.h> 30 #include <linux/slab.h> 31 #include <linux/cache.h> 32 #include <linux/percpu.h> 33 #include <net/checksum.h> 34 #include <net/request_sock.h> 35 #include <net/sock.h> 36 #include <net/snmp.h> 37 #include <net/ip.h> 38 #if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE) 39 #include <linux/ipv6.h> 40 #endif 41 #include <linux/seq_file.h> 42 43 /* This is for all connections with a full identity, no wildcards. 44 * New scheme, half the table is for TIME_WAIT, the other half is 45 * for the rest. I'll experiment with dynamic table growth later. 46 */ 47 struct tcp_ehash_bucket { 48 rwlock_t lock; 49 struct hlist_head chain; 50 } __attribute__((__aligned__(8))); 51 52 /* This is for listening sockets, thus all sockets which possess wildcards. */ 53 #define TCP_LHTABLE_SIZE 32 /* Yes, really, this is all you need. */ 54 55 /* There are a few simple rules, which allow for local port reuse by 56 * an application. In essence: 57 * 58 * 1) Sockets bound to different interfaces may share a local port. 59 * Failing that, goto test 2. 60 * 2) If all sockets have sk->sk_reuse set, and none of them are in 61 * TCP_LISTEN state, the port may be shared. 62 * Failing that, goto test 3. 63 * 3) If all sockets are bound to a specific inet_sk(sk)->rcv_saddr local 64 * address, and none of them are the same, the port may be 65 * shared. 66 * Failing this, the port cannot be shared. 67 * 68 * The interesting point, is test #2. This is what an FTP server does 69 * all day. To optimize this case we use a specific flag bit defined 70 * below. As we add sockets to a bind bucket list, we perform a 71 * check of: (newsk->sk_reuse && (newsk->sk_state != TCP_LISTEN)) 72 * As long as all sockets added to a bind bucket pass this test, 73 * the flag bit will be set. 74 * The resulting situation is that tcp_v[46]_verify_bind() can just check 75 * for this flag bit, if it is set and the socket trying to bind has 76 * sk->sk_reuse set, we don't even have to walk the owners list at all, 77 * we return that it is ok to bind this socket to the requested local port. 78 * 79 * Sounds like a lot of work, but it is worth it. In a more naive 80 * implementation (ie. current FreeBSD etc.) the entire list of ports 81 * must be walked for each data port opened by an ftp server. Needless 82 * to say, this does not scale at all. With a couple thousand FTP 83 * users logged onto your box, isn't it nice to know that new data 84 * ports are created in O(1) time? I thought so. ;-) -DaveM 85 */ 86 struct tcp_bind_bucket { 87 unsigned short port; 88 signed short fastreuse; 89 struct hlist_node node; 90 struct hlist_head owners; 91 }; 92 93 #define tb_for_each(tb, node, head) hlist_for_each_entry(tb, node, head, node) 94 95 struct tcp_bind_hashbucket { 96 spinlock_t lock; 97 struct hlist_head chain; 98 }; 99 100 static inline struct tcp_bind_bucket *__tb_head(struct tcp_bind_hashbucket *head) 101 { 102 return hlist_entry(head->chain.first, struct tcp_bind_bucket, node); 103 } 104 105 static inline struct tcp_bind_bucket *tb_head(struct tcp_bind_hashbucket *head) 106 { 107 return hlist_empty(&head->chain) ? NULL : __tb_head(head); 108 } 109 110 extern struct tcp_hashinfo { 111 /* This is for sockets with full identity only. Sockets here will 112 * always be without wildcards and will have the following invariant: 113 * 114 * TCP_ESTABLISHED <= sk->sk_state < TCP_CLOSE 115 * 116 * First half of the table is for sockets not in TIME_WAIT, second half 117 * is for TIME_WAIT sockets only. 118 */ 119 struct tcp_ehash_bucket *__tcp_ehash; 120 121 /* Ok, let's try this, I give up, we do need a local binding 122 * TCP hash as well as the others for fast bind/connect. 123 */ 124 struct tcp_bind_hashbucket *__tcp_bhash; 125 126 int __tcp_bhash_size; 127 int __tcp_ehash_size; 128 129 /* All sockets in TCP_LISTEN state will be in here. This is the only 130 * table where wildcard'd TCP sockets can exist. Hash function here 131 * is just local port number. 132 */ 133 struct hlist_head __tcp_listening_hash[TCP_LHTABLE_SIZE]; 134 135 /* All the above members are written once at bootup and 136 * never written again _or_ are predominantly read-access. 137 * 138 * Now align to a new cache line as all the following members 139 * are often dirty. 140 */ 141 rwlock_t __tcp_lhash_lock ____cacheline_aligned; 142 atomic_t __tcp_lhash_users; 143 wait_queue_head_t __tcp_lhash_wait; 144 spinlock_t __tcp_portalloc_lock; 145 } tcp_hashinfo; 146 147 #define tcp_ehash (tcp_hashinfo.__tcp_ehash) 148 #define tcp_bhash (tcp_hashinfo.__tcp_bhash) 149 #define tcp_ehash_size (tcp_hashinfo.__tcp_ehash_size) 150 #define tcp_bhash_size (tcp_hashinfo.__tcp_bhash_size) 151 #define tcp_listening_hash (tcp_hashinfo.__tcp_listening_hash) 152 #define tcp_lhash_lock (tcp_hashinfo.__tcp_lhash_lock) 153 #define tcp_lhash_users (tcp_hashinfo.__tcp_lhash_users) 154 #define tcp_lhash_wait (tcp_hashinfo.__tcp_lhash_wait) 155 #define tcp_portalloc_lock (tcp_hashinfo.__tcp_portalloc_lock) 156 157 extern kmem_cache_t *tcp_bucket_cachep; 158 extern struct tcp_bind_bucket *tcp_bucket_create(struct tcp_bind_hashbucket *head, 159 unsigned short snum); 160 extern void tcp_bucket_destroy(struct tcp_bind_bucket *tb); 161 extern void tcp_bucket_unlock(struct sock *sk); 162 extern int tcp_port_rover; 163 164 /* These are AF independent. */ 165 static __inline__ int tcp_bhashfn(__u16 lport) 166 { 167 return (lport & (tcp_bhash_size - 1)); 168 } 169 170 extern void tcp_bind_hash(struct sock *sk, struct tcp_bind_bucket *tb, 171 unsigned short snum); 172 173 #if (BITS_PER_LONG == 64) 174 #define TCP_ADDRCMP_ALIGN_BYTES 8 175 #else 176 #define TCP_ADDRCMP_ALIGN_BYTES 4 177 #endif 178 179 /* This is a TIME_WAIT bucket. It works around the memory consumption 180 * problems of sockets in such a state on heavily loaded servers, but 181 * without violating the protocol specification. 182 */ 183 struct tcp_tw_bucket { 184 /* 185 * Now struct sock also uses sock_common, so please just 186 * don't add nothing before this first member (__tw_common) --acme 187 */ 188 struct sock_common __tw_common; 189 #define tw_family __tw_common.skc_family 190 #define tw_state __tw_common.skc_state 191 #define tw_reuse __tw_common.skc_reuse 192 #define tw_bound_dev_if __tw_common.skc_bound_dev_if 193 #define tw_node __tw_common.skc_node 194 #define tw_bind_node __tw_common.skc_bind_node 195 #define tw_refcnt __tw_common.skc_refcnt 196 volatile unsigned char tw_substate; 197 unsigned char tw_rcv_wscale; 198 __u16 tw_sport; 199 /* Socket demultiplex comparisons on incoming packets. */ 200 /* these five are in inet_sock */ 201 __u32 tw_daddr 202 __attribute__((aligned(TCP_ADDRCMP_ALIGN_BYTES))); 203 __u32 tw_rcv_saddr; 204 __u16 tw_dport; 205 __u16 tw_num; 206 /* And these are ours. */ 207 int tw_hashent; 208 int tw_timeout; 209 __u32 tw_rcv_nxt; 210 __u32 tw_snd_nxt; 211 __u32 tw_rcv_wnd; 212 __u32 tw_ts_recent; 213 long tw_ts_recent_stamp; 214 unsigned long tw_ttd; 215 struct tcp_bind_bucket *tw_tb; 216 struct hlist_node tw_death_node; 217 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) 218 struct in6_addr tw_v6_daddr; 219 struct in6_addr tw_v6_rcv_saddr; 220 int tw_v6_ipv6only; 221 #endif 222 }; 223 224 static __inline__ void tw_add_node(struct tcp_tw_bucket *tw, 225 struct hlist_head *list) 226 { 227 hlist_add_head(&tw->tw_node, list); 228 } 229 230 static __inline__ void tw_add_bind_node(struct tcp_tw_bucket *tw, 231 struct hlist_head *list) 232 { 233 hlist_add_head(&tw->tw_bind_node, list); 234 } 235 236 static inline int tw_dead_hashed(struct tcp_tw_bucket *tw) 237 { 238 return tw->tw_death_node.pprev != NULL; 239 } 240 241 static __inline__ void tw_dead_node_init(struct tcp_tw_bucket *tw) 242 { 243 tw->tw_death_node.pprev = NULL; 244 } 245 246 static __inline__ void __tw_del_dead_node(struct tcp_tw_bucket *tw) 247 { 248 __hlist_del(&tw->tw_death_node); 249 tw_dead_node_init(tw); 250 } 251 252 static __inline__ int tw_del_dead_node(struct tcp_tw_bucket *tw) 253 { 254 if (tw_dead_hashed(tw)) { 255 __tw_del_dead_node(tw); 256 return 1; 257 } 258 return 0; 259 } 260 261 #define tw_for_each(tw, node, head) \ 262 hlist_for_each_entry(tw, node, head, tw_node) 263 264 #define tw_for_each_inmate(tw, node, jail) \ 265 hlist_for_each_entry(tw, node, jail, tw_death_node) 266 267 #define tw_for_each_inmate_safe(tw, node, safe, jail) \ 268 hlist_for_each_entry_safe(tw, node, safe, jail, tw_death_node) 269 270 #define tcptw_sk(__sk) ((struct tcp_tw_bucket *)(__sk)) 271 272 static inline u32 tcp_v4_rcv_saddr(const struct sock *sk) 273 { 274 return likely(sk->sk_state != TCP_TIME_WAIT) ? 275 inet_sk(sk)->rcv_saddr : tcptw_sk(sk)->tw_rcv_saddr; 276 } 277 278 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) 279 static inline struct in6_addr *__tcp_v6_rcv_saddr(const struct sock *sk) 280 { 281 return likely(sk->sk_state != TCP_TIME_WAIT) ? 282 &inet6_sk(sk)->rcv_saddr : &tcptw_sk(sk)->tw_v6_rcv_saddr; 283 } 284 285 static inline struct in6_addr *tcp_v6_rcv_saddr(const struct sock *sk) 286 { 287 return sk->sk_family == AF_INET6 ? __tcp_v6_rcv_saddr(sk) : NULL; 288 } 289 290 #define tcptw_sk_ipv6only(__sk) (tcptw_sk(__sk)->tw_v6_ipv6only) 291 292 static inline int tcp_v6_ipv6only(const struct sock *sk) 293 { 294 return likely(sk->sk_state != TCP_TIME_WAIT) ? 295 ipv6_only_sock(sk) : tcptw_sk_ipv6only(sk); 296 } 297 #else 298 # define __tcp_v6_rcv_saddr(__sk) NULL 299 # define tcp_v6_rcv_saddr(__sk) NULL 300 # define tcptw_sk_ipv6only(__sk) 0 301 # define tcp_v6_ipv6only(__sk) 0 302 #endif 303 304 extern kmem_cache_t *tcp_timewait_cachep; 305 306 static inline void tcp_tw_put(struct tcp_tw_bucket *tw) 307 { 308 if (atomic_dec_and_test(&tw->tw_refcnt)) { 309 #ifdef INET_REFCNT_DEBUG 310 printk(KERN_DEBUG "tw_bucket %p released\n", tw); 311 #endif 312 kmem_cache_free(tcp_timewait_cachep, tw); 313 } 314 } 315 316 extern atomic_t tcp_orphan_count; 317 extern int tcp_tw_count; 318 extern void tcp_time_wait(struct sock *sk, int state, int timeo); 319 extern void tcp_tw_deschedule(struct tcp_tw_bucket *tw); 320 321 322 /* Socket demux engine toys. */ 323 #ifdef __BIG_ENDIAN 324 #define TCP_COMBINED_PORTS(__sport, __dport) \ 325 (((__u32)(__sport)<<16) | (__u32)(__dport)) 326 #else /* __LITTLE_ENDIAN */ 327 #define TCP_COMBINED_PORTS(__sport, __dport) \ 328 (((__u32)(__dport)<<16) | (__u32)(__sport)) 329 #endif 330 331 #if (BITS_PER_LONG == 64) 332 #ifdef __BIG_ENDIAN 333 #define TCP_V4_ADDR_COOKIE(__name, __saddr, __daddr) \ 334 __u64 __name = (((__u64)(__saddr))<<32)|((__u64)(__daddr)); 335 #else /* __LITTLE_ENDIAN */ 336 #define TCP_V4_ADDR_COOKIE(__name, __saddr, __daddr) \ 337 __u64 __name = (((__u64)(__daddr))<<32)|((__u64)(__saddr)); 338 #endif /* __BIG_ENDIAN */ 339 #define TCP_IPV4_MATCH(__sk, __cookie, __saddr, __daddr, __ports, __dif)\ 340 (((*((__u64 *)&(inet_sk(__sk)->daddr)))== (__cookie)) && \ 341 ((*((__u32 *)&(inet_sk(__sk)->dport)))== (__ports)) && \ 342 (!((__sk)->sk_bound_dev_if) || ((__sk)->sk_bound_dev_if == (__dif)))) 343 #define TCP_IPV4_TW_MATCH(__sk, __cookie, __saddr, __daddr, __ports, __dif)\ 344 (((*((__u64 *)&(tcptw_sk(__sk)->tw_daddr))) == (__cookie)) && \ 345 ((*((__u32 *)&(tcptw_sk(__sk)->tw_dport))) == (__ports)) && \ 346 (!((__sk)->sk_bound_dev_if) || ((__sk)->sk_bound_dev_if == (__dif)))) 347 #else /* 32-bit arch */ 348 #define TCP_V4_ADDR_COOKIE(__name, __saddr, __daddr) 349 #define TCP_IPV4_MATCH(__sk, __cookie, __saddr, __daddr, __ports, __dif)\ 350 ((inet_sk(__sk)->daddr == (__saddr)) && \ 351 (inet_sk(__sk)->rcv_saddr == (__daddr)) && \ 352 ((*((__u32 *)&(inet_sk(__sk)->dport)))== (__ports)) && \ 353 (!((__sk)->sk_bound_dev_if) || ((__sk)->sk_bound_dev_if == (__dif)))) 354 #define TCP_IPV4_TW_MATCH(__sk, __cookie, __saddr, __daddr, __ports, __dif)\ 355 ((tcptw_sk(__sk)->tw_daddr == (__saddr)) && \ 356 (tcptw_sk(__sk)->tw_rcv_saddr == (__daddr)) && \ 357 ((*((__u32 *)&(tcptw_sk(__sk)->tw_dport))) == (__ports)) && \ 358 (!((__sk)->sk_bound_dev_if) || ((__sk)->sk_bound_dev_if == (__dif)))) 359 #endif /* 64-bit arch */ 360 361 #define TCP_IPV6_MATCH(__sk, __saddr, __daddr, __ports, __dif) \ 362 (((*((__u32 *)&(inet_sk(__sk)->dport)))== (__ports)) && \ 363 ((__sk)->sk_family == AF_INET6) && \ 364 ipv6_addr_equal(&inet6_sk(__sk)->daddr, (__saddr)) && \ 365 ipv6_addr_equal(&inet6_sk(__sk)->rcv_saddr, (__daddr)) && \ 366 (!((__sk)->sk_bound_dev_if) || ((__sk)->sk_bound_dev_if == (__dif)))) 367 368 /* These can have wildcards, don't try too hard. */ 369 static __inline__ int tcp_lhashfn(unsigned short num) 370 { 371 return num & (TCP_LHTABLE_SIZE - 1); 372 } 373 374 static __inline__ int tcp_sk_listen_hashfn(struct sock *sk) 375 { 376 return tcp_lhashfn(inet_sk(sk)->num); 377 } 378 379 #define MAX_TCP_HEADER (128 + MAX_HEADER) 380 381 /* 382 * Never offer a window over 32767 without using window scaling. Some 383 * poor stacks do signed 16bit maths! 384 */ 385 #define MAX_TCP_WINDOW 32767U 386 387 /* Minimal accepted MSS. It is (60+60+8) - (20+20). */ 388 #define TCP_MIN_MSS 88U 389 390 /* Minimal RCV_MSS. */ 391 #define TCP_MIN_RCVMSS 536U 392 393 /* After receiving this amount of duplicate ACKs fast retransmit starts. */ 394 #define TCP_FASTRETRANS_THRESH 3 395 396 /* Maximal reordering. */ 397 #define TCP_MAX_REORDERING 127 398 399 /* Maximal number of ACKs sent quickly to accelerate slow-start. */ 400 #define TCP_MAX_QUICKACKS 16U 401 402 /* urg_data states */ 403 #define TCP_URG_VALID 0x0100 404 #define TCP_URG_NOTYET 0x0200 405 #define TCP_URG_READ 0x0400 406 407 #define TCP_RETR1 3 /* 408 * This is how many retries it does before it 409 * tries to figure out if the gateway is 410 * down. Minimal RFC value is 3; it corresponds 411 * to ~3sec-8min depending on RTO. 412 */ 413 414 #define TCP_RETR2 15 /* 415 * This should take at least 416 * 90 minutes to time out. 417 * RFC1122 says that the limit is 100 sec. 418 * 15 is ~13-30min depending on RTO. 419 */ 420 421 #define TCP_SYN_RETRIES 5 /* number of times to retry active opening a 422 * connection: ~180sec is RFC minumum */ 423 424 #define TCP_SYNACK_RETRIES 5 /* number of times to retry passive opening a 425 * connection: ~180sec is RFC minumum */ 426 427 428 #define TCP_ORPHAN_RETRIES 7 /* number of times to retry on an orphaned 429 * socket. 7 is ~50sec-16min. 430 */ 431 432 433 #define TCP_TIMEWAIT_LEN (60*HZ) /* how long to wait to destroy TIME-WAIT 434 * state, about 60 seconds */ 435 #define TCP_FIN_TIMEOUT TCP_TIMEWAIT_LEN 436 /* BSD style FIN_WAIT2 deadlock breaker. 437 * It used to be 3min, new value is 60sec, 438 * to combine FIN-WAIT-2 timeout with 439 * TIME-WAIT timer. 440 */ 441 442 #define TCP_DELACK_MAX ((unsigned)(HZ/5)) /* maximal time to delay before sending an ACK */ 443 #if HZ >= 100 444 #define TCP_DELACK_MIN ((unsigned)(HZ/25)) /* minimal time to delay before sending an ACK */ 445 #define TCP_ATO_MIN ((unsigned)(HZ/25)) 446 #else 447 #define TCP_DELACK_MIN 4U 448 #define TCP_ATO_MIN 4U 449 #endif 450 #define TCP_RTO_MAX ((unsigned)(120*HZ)) 451 #define TCP_RTO_MIN ((unsigned)(HZ/5)) 452 #define TCP_TIMEOUT_INIT ((unsigned)(3*HZ)) /* RFC 1122 initial RTO value */ 453 454 #define TCP_RESOURCE_PROBE_INTERVAL ((unsigned)(HZ/2U)) /* Maximal interval between probes 455 * for local resources. 456 */ 457 458 #define TCP_KEEPALIVE_TIME (120*60*HZ) /* two hours */ 459 #define TCP_KEEPALIVE_PROBES 9 /* Max of 9 keepalive probes */ 460 #define TCP_KEEPALIVE_INTVL (75*HZ) 461 462 #define MAX_TCP_KEEPIDLE 32767 463 #define MAX_TCP_KEEPINTVL 32767 464 #define MAX_TCP_KEEPCNT 127 465 #define MAX_TCP_SYNCNT 127 466 467 #define TCP_SYNQ_INTERVAL (HZ/5) /* Period of SYNACK timer */ 468 #define TCP_SYNQ_HSIZE 512 /* Size of SYNACK hash table */ 469 470 #define TCP_PAWS_24DAYS (60 * 60 * 24 * 24) 471 #define TCP_PAWS_MSL 60 /* Per-host timestamps are invalidated 472 * after this time. It should be equal 473 * (or greater than) TCP_TIMEWAIT_LEN 474 * to provide reliability equal to one 475 * provided by timewait state. 476 */ 477 #define TCP_PAWS_WINDOW 1 /* Replay window for per-host 478 * timestamps. It must be less than 479 * minimal timewait lifetime. 480 */ 481 482 #define TCP_TW_RECYCLE_SLOTS_LOG 5 483 #define TCP_TW_RECYCLE_SLOTS (1<<TCP_TW_RECYCLE_SLOTS_LOG) 484 485 /* If time > 4sec, it is "slow" path, no recycling is required, 486 so that we select tick to get range about 4 seconds. 487 */ 488 489 #if HZ <= 16 || HZ > 4096 490 # error Unsupported: HZ <= 16 or HZ > 4096 491 #elif HZ <= 32 492 # define TCP_TW_RECYCLE_TICK (5+2-TCP_TW_RECYCLE_SLOTS_LOG) 493 #elif HZ <= 64 494 # define TCP_TW_RECYCLE_TICK (6+2-TCP_TW_RECYCLE_SLOTS_LOG) 495 #elif HZ <= 128 496 # define TCP_TW_RECYCLE_TICK (7+2-TCP_TW_RECYCLE_SLOTS_LOG) 497 #elif HZ <= 256 498 # define TCP_TW_RECYCLE_TICK (8+2-TCP_TW_RECYCLE_SLOTS_LOG) 499 #elif HZ <= 512 500 # define TCP_TW_RECYCLE_TICK (9+2-TCP_TW_RECYCLE_SLOTS_LOG) 501 #elif HZ <= 1024 502 # define TCP_TW_RECYCLE_TICK (10+2-TCP_TW_RECYCLE_SLOTS_LOG) 503 #elif HZ <= 2048 504 # define TCP_TW_RECYCLE_TICK (11+2-TCP_TW_RECYCLE_SLOTS_LOG) 505 #else 506 # define TCP_TW_RECYCLE_TICK (12+2-TCP_TW_RECYCLE_SLOTS_LOG) 507 #endif 508 /* 509 * TCP option 510 */ 511 512 #define TCPOPT_NOP 1 /* Padding */ 513 #define TCPOPT_EOL 0 /* End of options */ 514 #define TCPOPT_MSS 2 /* Segment size negotiating */ 515 #define TCPOPT_WINDOW 3 /* Window scaling */ 516 #define TCPOPT_SACK_PERM 4 /* SACK Permitted */ 517 #define TCPOPT_SACK 5 /* SACK Block */ 518 #define TCPOPT_TIMESTAMP 8 /* Better RTT estimations/PAWS */ 519 520 /* 521 * TCP option lengths 522 */ 523 524 #define TCPOLEN_MSS 4 525 #define TCPOLEN_WINDOW 3 526 #define TCPOLEN_SACK_PERM 2 527 #define TCPOLEN_TIMESTAMP 10 528 529 /* But this is what stacks really send out. */ 530 #define TCPOLEN_TSTAMP_ALIGNED 12 531 #define TCPOLEN_WSCALE_ALIGNED 4 532 #define TCPOLEN_SACKPERM_ALIGNED 4 533 #define TCPOLEN_SACK_BASE 2 534 #define TCPOLEN_SACK_BASE_ALIGNED 4 535 #define TCPOLEN_SACK_PERBLOCK 8 536 537 #define TCP_TIME_RETRANS 1 /* Retransmit timer */ 538 #define TCP_TIME_DACK 2 /* Delayed ack timer */ 539 #define TCP_TIME_PROBE0 3 /* Zero window probe timer */ 540 #define TCP_TIME_KEEPOPEN 4 /* Keepalive timer */ 541 542 /* Flags in tp->nonagle */ 543 #define TCP_NAGLE_OFF 1 /* Nagle's algo is disabled */ 544 #define TCP_NAGLE_CORK 2 /* Socket is corked */ 545 #define TCP_NAGLE_PUSH 4 /* Cork is overriden for already queued data */ 546 547 /* sysctl variables for tcp */ 548 extern int sysctl_tcp_timestamps; 549 extern int sysctl_tcp_window_scaling; 550 extern int sysctl_tcp_sack; 551 extern int sysctl_tcp_fin_timeout; 552 extern int sysctl_tcp_tw_recycle; 553 extern int sysctl_tcp_keepalive_time; 554 extern int sysctl_tcp_keepalive_probes; 555 extern int sysctl_tcp_keepalive_intvl; 556 extern int sysctl_tcp_syn_retries; 557 extern int sysctl_tcp_synack_retries; 558 extern int sysctl_tcp_retries1; 559 extern int sysctl_tcp_retries2; 560 extern int sysctl_tcp_orphan_retries; 561 extern int sysctl_tcp_syncookies; 562 extern int sysctl_tcp_retrans_collapse; 563 extern int sysctl_tcp_stdurg; 564 extern int sysctl_tcp_rfc1337; 565 extern int sysctl_tcp_abort_on_overflow; 566 extern int sysctl_tcp_max_orphans; 567 extern int sysctl_tcp_max_tw_buckets; 568 extern int sysctl_tcp_fack; 569 extern int sysctl_tcp_reordering; 570 extern int sysctl_tcp_ecn; 571 extern int sysctl_tcp_dsack; 572 extern int sysctl_tcp_mem[3]; 573 extern int sysctl_tcp_wmem[3]; 574 extern int sysctl_tcp_rmem[3]; 575 extern int sysctl_tcp_app_win; 576 extern int sysctl_tcp_adv_win_scale; 577 extern int sysctl_tcp_tw_reuse; 578 extern int sysctl_tcp_frto; 579 extern int sysctl_tcp_low_latency; 580 extern int sysctl_tcp_nometrics_save; 581 extern int sysctl_tcp_moderate_rcvbuf; 582 extern int sysctl_tcp_tso_win_divisor; 583 584 extern atomic_t tcp_memory_allocated; 585 extern atomic_t tcp_sockets_allocated; 586 extern int tcp_memory_pressure; 587 588 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) 589 #define TCP_INET_FAMILY(fam) ((fam) == AF_INET) 590 #else 591 #define TCP_INET_FAMILY(fam) 1 592 #endif 593 594 /* 595 * Pointers to address related TCP functions 596 * (i.e. things that depend on the address family) 597 */ 598 599 struct tcp_func { 600 int (*queue_xmit) (struct sk_buff *skb, 601 int ipfragok); 602 603 void (*send_check) (struct sock *sk, 604 struct tcphdr *th, 605 int len, 606 struct sk_buff *skb); 607 608 int (*rebuild_header) (struct sock *sk); 609 610 int (*conn_request) (struct sock *sk, 611 struct sk_buff *skb); 612 613 struct sock * (*syn_recv_sock) (struct sock *sk, 614 struct sk_buff *skb, 615 struct request_sock *req, 616 struct dst_entry *dst); 617 618 int (*remember_stamp) (struct sock *sk); 619 620 __u16 net_header_len; 621 622 int (*setsockopt) (struct sock *sk, 623 int level, 624 int optname, 625 char __user *optval, 626 int optlen); 627 628 int (*getsockopt) (struct sock *sk, 629 int level, 630 int optname, 631 char __user *optval, 632 int __user *optlen); 633 634 635 void (*addr2sockaddr) (struct sock *sk, 636 struct sockaddr *); 637 638 int sockaddr_len; 639 }; 640 641 /* 642 * The next routines deal with comparing 32 bit unsigned ints 643 * and worry about wraparound (automatic with unsigned arithmetic). 644 */ 645 646 static inline int before(__u32 seq1, __u32 seq2) 647 { 648 return (__s32)(seq1-seq2) < 0; 649 } 650 651 static inline int after(__u32 seq1, __u32 seq2) 652 { 653 return (__s32)(seq2-seq1) < 0; 654 } 655 656 657 /* is s2<=s1<=s3 ? */ 658 static inline int between(__u32 seq1, __u32 seq2, __u32 seq3) 659 { 660 return seq3 - seq2 >= seq1 - seq2; 661 } 662 663 664 extern struct proto tcp_prot; 665 666 DECLARE_SNMP_STAT(struct tcp_mib, tcp_statistics); 667 #define TCP_INC_STATS(field) SNMP_INC_STATS(tcp_statistics, field) 668 #define TCP_INC_STATS_BH(field) SNMP_INC_STATS_BH(tcp_statistics, field) 669 #define TCP_INC_STATS_USER(field) SNMP_INC_STATS_USER(tcp_statistics, field) 670 #define TCP_DEC_STATS(field) SNMP_DEC_STATS(tcp_statistics, field) 671 #define TCP_ADD_STATS_BH(field, val) SNMP_ADD_STATS_BH(tcp_statistics, field, val) 672 #define TCP_ADD_STATS_USER(field, val) SNMP_ADD_STATS_USER(tcp_statistics, field, val) 673 674 extern void tcp_put_port(struct sock *sk); 675 extern void tcp_inherit_port(struct sock *sk, struct sock *child); 676 677 extern void tcp_v4_err(struct sk_buff *skb, u32); 678 679 extern void tcp_shutdown (struct sock *sk, int how); 680 681 extern int tcp_v4_rcv(struct sk_buff *skb); 682 683 extern int tcp_v4_remember_stamp(struct sock *sk); 684 685 extern int tcp_v4_tw_remember_stamp(struct tcp_tw_bucket *tw); 686 687 extern int tcp_sendmsg(struct kiocb *iocb, struct sock *sk, 688 struct msghdr *msg, size_t size); 689 extern ssize_t tcp_sendpage(struct socket *sock, struct page *page, int offset, size_t size, int flags); 690 691 extern int tcp_ioctl(struct sock *sk, 692 int cmd, 693 unsigned long arg); 694 695 extern int tcp_rcv_state_process(struct sock *sk, 696 struct sk_buff *skb, 697 struct tcphdr *th, 698 unsigned len); 699 700 extern int tcp_rcv_established(struct sock *sk, 701 struct sk_buff *skb, 702 struct tcphdr *th, 703 unsigned len); 704 705 extern void tcp_rcv_space_adjust(struct sock *sk); 706 707 enum tcp_ack_state_t 708 { 709 TCP_ACK_SCHED = 1, 710 TCP_ACK_TIMER = 2, 711 TCP_ACK_PUSHED= 4 712 }; 713 714 static inline void tcp_schedule_ack(struct tcp_sock *tp) 715 { 716 tp->ack.pending |= TCP_ACK_SCHED; 717 } 718 719 static inline int tcp_ack_scheduled(struct tcp_sock *tp) 720 { 721 return tp->ack.pending&TCP_ACK_SCHED; 722 } 723 724 static __inline__ void tcp_dec_quickack_mode(struct tcp_sock *tp, unsigned int pkts) 725 { 726 if (tp->ack.quick) { 727 if (pkts >= tp->ack.quick) { 728 tp->ack.quick = 0; 729 730 /* Leaving quickack mode we deflate ATO. */ 731 tp->ack.ato = TCP_ATO_MIN; 732 } else 733 tp->ack.quick -= pkts; 734 } 735 } 736 737 extern void tcp_enter_quickack_mode(struct tcp_sock *tp); 738 739 static __inline__ void tcp_delack_init(struct tcp_sock *tp) 740 { 741 memset(&tp->ack, 0, sizeof(tp->ack)); 742 } 743 744 static inline void tcp_clear_options(struct tcp_options_received *rx_opt) 745 { 746 rx_opt->tstamp_ok = rx_opt->sack_ok = rx_opt->wscale_ok = rx_opt->snd_wscale = 0; 747 } 748 749 enum tcp_tw_status 750 { 751 TCP_TW_SUCCESS = 0, 752 TCP_TW_RST = 1, 753 TCP_TW_ACK = 2, 754 TCP_TW_SYN = 3 755 }; 756 757 758 extern enum tcp_tw_status tcp_timewait_state_process(struct tcp_tw_bucket *tw, 759 struct sk_buff *skb, 760 struct tcphdr *th, 761 unsigned len); 762 763 extern struct sock * tcp_check_req(struct sock *sk,struct sk_buff *skb, 764 struct request_sock *req, 765 struct request_sock **prev); 766 extern int tcp_child_process(struct sock *parent, 767 struct sock *child, 768 struct sk_buff *skb); 769 extern void tcp_enter_frto(struct sock *sk); 770 extern void tcp_enter_loss(struct sock *sk, int how); 771 extern void tcp_clear_retrans(struct tcp_sock *tp); 772 extern void tcp_update_metrics(struct sock *sk); 773 774 extern void tcp_close(struct sock *sk, 775 long timeout); 776 extern struct sock * tcp_accept(struct sock *sk, int flags, int *err); 777 extern unsigned int tcp_poll(struct file * file, struct socket *sock, struct poll_table_struct *wait); 778 779 extern int tcp_getsockopt(struct sock *sk, int level, 780 int optname, 781 char __user *optval, 782 int __user *optlen); 783 extern int tcp_setsockopt(struct sock *sk, int level, 784 int optname, char __user *optval, 785 int optlen); 786 extern void tcp_set_keepalive(struct sock *sk, int val); 787 extern int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, 788 struct msghdr *msg, 789 size_t len, int nonblock, 790 int flags, int *addr_len); 791 792 extern int tcp_listen_start(struct sock *sk); 793 794 extern void tcp_parse_options(struct sk_buff *skb, 795 struct tcp_options_received *opt_rx, 796 int estab); 797 798 /* 799 * TCP v4 functions exported for the inet6 API 800 */ 801 802 extern int tcp_v4_rebuild_header(struct sock *sk); 803 804 extern int tcp_v4_build_header(struct sock *sk, 805 struct sk_buff *skb); 806 807 extern void tcp_v4_send_check(struct sock *sk, 808 struct tcphdr *th, int len, 809 struct sk_buff *skb); 810 811 extern int tcp_v4_conn_request(struct sock *sk, 812 struct sk_buff *skb); 813 814 extern struct sock * tcp_create_openreq_child(struct sock *sk, 815 struct request_sock *req, 816 struct sk_buff *skb); 817 818 extern struct sock * tcp_v4_syn_recv_sock(struct sock *sk, 819 struct sk_buff *skb, 820 struct request_sock *req, 821 struct dst_entry *dst); 822 823 extern int tcp_v4_do_rcv(struct sock *sk, 824 struct sk_buff *skb); 825 826 extern int tcp_v4_connect(struct sock *sk, 827 struct sockaddr *uaddr, 828 int addr_len); 829 830 extern int tcp_connect(struct sock *sk); 831 832 extern struct sk_buff * tcp_make_synack(struct sock *sk, 833 struct dst_entry *dst, 834 struct request_sock *req); 835 836 extern int tcp_disconnect(struct sock *sk, int flags); 837 838 extern void tcp_unhash(struct sock *sk); 839 840 extern int tcp_v4_hash_connecting(struct sock *sk); 841 842 843 /* From syncookies.c */ 844 extern struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb, 845 struct ip_options *opt); 846 extern __u32 cookie_v4_init_sequence(struct sock *sk, struct sk_buff *skb, 847 __u16 *mss); 848 849 /* tcp_output.c */ 850 851 extern void __tcp_push_pending_frames(struct sock *sk, struct tcp_sock *tp, 852 unsigned int cur_mss, int nonagle); 853 extern int tcp_may_send_now(struct sock *sk, struct tcp_sock *tp); 854 extern int tcp_retransmit_skb(struct sock *, struct sk_buff *); 855 extern void tcp_xmit_retransmit_queue(struct sock *); 856 extern void tcp_simple_retransmit(struct sock *); 857 extern int tcp_trim_head(struct sock *, struct sk_buff *, u32); 858 859 extern void tcp_send_probe0(struct sock *); 860 extern void tcp_send_partial(struct sock *); 861 extern int tcp_write_wakeup(struct sock *); 862 extern void tcp_send_fin(struct sock *sk); 863 extern void tcp_send_active_reset(struct sock *sk, 864 unsigned int __nocast priority); 865 extern int tcp_send_synack(struct sock *); 866 extern void tcp_push_one(struct sock *, unsigned int mss_now); 867 extern void tcp_send_ack(struct sock *sk); 868 extern void tcp_send_delayed_ack(struct sock *sk); 869 870 /* tcp_input.c */ 871 extern void tcp_cwnd_application_limited(struct sock *sk); 872 873 /* tcp_timer.c */ 874 extern void tcp_init_xmit_timers(struct sock *); 875 extern void tcp_clear_xmit_timers(struct sock *); 876 877 extern void tcp_delete_keepalive_timer(struct sock *); 878 extern void tcp_reset_keepalive_timer(struct sock *, unsigned long); 879 extern unsigned int tcp_sync_mss(struct sock *sk, u32 pmtu); 880 extern unsigned int tcp_current_mss(struct sock *sk, int large); 881 882 #ifdef TCP_DEBUG 883 extern const char tcp_timer_bug_msg[]; 884 #endif 885 886 /* tcp_diag.c */ 887 extern void tcp_get_info(struct sock *, struct tcp_info *); 888 889 /* Read 'sendfile()'-style from a TCP socket */ 890 typedef int (*sk_read_actor_t)(read_descriptor_t *, struct sk_buff *, 891 unsigned int, size_t); 892 extern int tcp_read_sock(struct sock *sk, read_descriptor_t *desc, 893 sk_read_actor_t recv_actor); 894 895 static inline void tcp_clear_xmit_timer(struct sock *sk, int what) 896 { 897 struct tcp_sock *tp = tcp_sk(sk); 898 899 switch (what) { 900 case TCP_TIME_RETRANS: 901 case TCP_TIME_PROBE0: 902 tp->pending = 0; 903 904 #ifdef TCP_CLEAR_TIMERS 905 sk_stop_timer(sk, &tp->retransmit_timer); 906 #endif 907 break; 908 case TCP_TIME_DACK: 909 tp->ack.blocked = 0; 910 tp->ack.pending = 0; 911 912 #ifdef TCP_CLEAR_TIMERS 913 sk_stop_timer(sk, &tp->delack_timer); 914 #endif 915 break; 916 default: 917 #ifdef TCP_DEBUG 918 printk(tcp_timer_bug_msg); 919 #endif 920 return; 921 }; 922 923 } 924 925 /* 926 * Reset the retransmission timer 927 */ 928 static inline void tcp_reset_xmit_timer(struct sock *sk, int what, unsigned long when) 929 { 930 struct tcp_sock *tp = tcp_sk(sk); 931 932 if (when > TCP_RTO_MAX) { 933 #ifdef TCP_DEBUG 934 printk(KERN_DEBUG "reset_xmit_timer sk=%p %d when=0x%lx, caller=%p\n", sk, what, when, current_text_addr()); 935 #endif 936 when = TCP_RTO_MAX; 937 } 938 939 switch (what) { 940 case TCP_TIME_RETRANS: 941 case TCP_TIME_PROBE0: 942 tp->pending = what; 943 tp->timeout = jiffies+when; 944 sk_reset_timer(sk, &tp->retransmit_timer, tp->timeout); 945 break; 946 947 case TCP_TIME_DACK: 948 tp->ack.pending |= TCP_ACK_TIMER; 949 tp->ack.timeout = jiffies+when; 950 sk_reset_timer(sk, &tp->delack_timer, tp->ack.timeout); 951 break; 952 953 default: 954 #ifdef TCP_DEBUG 955 printk(tcp_timer_bug_msg); 956 #endif 957 return; 958 }; 959 } 960 961 /* Initialize RCV_MSS value. 962 * RCV_MSS is an our guess about MSS used by the peer. 963 * We haven't any direct information about the MSS. 964 * It's better to underestimate the RCV_MSS rather than overestimate. 965 * Overestimations make us ACKing less frequently than needed. 966 * Underestimations are more easy to detect and fix by tcp_measure_rcv_mss(). 967 */ 968 969 static inline void tcp_initialize_rcv_mss(struct sock *sk) 970 { 971 struct tcp_sock *tp = tcp_sk(sk); 972 unsigned int hint = min_t(unsigned int, tp->advmss, tp->mss_cache); 973 974 hint = min(hint, tp->rcv_wnd/2); 975 hint = min(hint, TCP_MIN_RCVMSS); 976 hint = max(hint, TCP_MIN_MSS); 977 978 tp->ack.rcv_mss = hint; 979 } 980 981 static __inline__ void __tcp_fast_path_on(struct tcp_sock *tp, u32 snd_wnd) 982 { 983 tp->pred_flags = htonl((tp->tcp_header_len << 26) | 984 ntohl(TCP_FLAG_ACK) | 985 snd_wnd); 986 } 987 988 static __inline__ void tcp_fast_path_on(struct tcp_sock *tp) 989 { 990 __tcp_fast_path_on(tp, tp->snd_wnd >> tp->rx_opt.snd_wscale); 991 } 992 993 static inline void tcp_fast_path_check(struct sock *sk, struct tcp_sock *tp) 994 { 995 if (skb_queue_empty(&tp->out_of_order_queue) && 996 tp->rcv_wnd && 997 atomic_read(&sk->sk_rmem_alloc) < sk->sk_rcvbuf && 998 !tp->urg_data) 999 tcp_fast_path_on(tp); 1000 } 1001 1002 /* Compute the actual receive window we are currently advertising. 1003 * Rcv_nxt can be after the window if our peer push more data 1004 * than the offered window. 1005 */ 1006 static __inline__ u32 tcp_receive_window(const struct tcp_sock *tp) 1007 { 1008 s32 win = tp->rcv_wup + tp->rcv_wnd - tp->rcv_nxt; 1009 1010 if (win < 0) 1011 win = 0; 1012 return (u32) win; 1013 } 1014 1015 /* Choose a new window, without checks for shrinking, and without 1016 * scaling applied to the result. The caller does these things 1017 * if necessary. This is a "raw" window selection. 1018 */ 1019 extern u32 __tcp_select_window(struct sock *sk); 1020 1021 /* TCP timestamps are only 32-bits, this causes a slight 1022 * complication on 64-bit systems since we store a snapshot 1023 * of jiffies in the buffer control blocks below. We decidely 1024 * only use of the low 32-bits of jiffies and hide the ugly 1025 * casts with the following macro. 1026 */ 1027 #define tcp_time_stamp ((__u32)(jiffies)) 1028 1029 /* This is what the send packet queueing engine uses to pass 1030 * TCP per-packet control information to the transmission 1031 * code. We also store the host-order sequence numbers in 1032 * here too. This is 36 bytes on 32-bit architectures, 1033 * 40 bytes on 64-bit machines, if this grows please adjust 1034 * skbuff.h:skbuff->cb[xxx] size appropriately. 1035 */ 1036 struct tcp_skb_cb { 1037 union { 1038 struct inet_skb_parm h4; 1039 #if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE) 1040 struct inet6_skb_parm h6; 1041 #endif 1042 } header; /* For incoming frames */ 1043 __u32 seq; /* Starting sequence number */ 1044 __u32 end_seq; /* SEQ + FIN + SYN + datalen */ 1045 __u32 when; /* used to compute rtt's */ 1046 __u8 flags; /* TCP header flags. */ 1047 1048 /* NOTE: These must match up to the flags byte in a 1049 * real TCP header. 1050 */ 1051 #define TCPCB_FLAG_FIN 0x01 1052 #define TCPCB_FLAG_SYN 0x02 1053 #define TCPCB_FLAG_RST 0x04 1054 #define TCPCB_FLAG_PSH 0x08 1055 #define TCPCB_FLAG_ACK 0x10 1056 #define TCPCB_FLAG_URG 0x20 1057 #define TCPCB_FLAG_ECE 0x40 1058 #define TCPCB_FLAG_CWR 0x80 1059 1060 __u8 sacked; /* State flags for SACK/FACK. */ 1061 #define TCPCB_SACKED_ACKED 0x01 /* SKB ACK'd by a SACK block */ 1062 #define TCPCB_SACKED_RETRANS 0x02 /* SKB retransmitted */ 1063 #define TCPCB_LOST 0x04 /* SKB is lost */ 1064 #define TCPCB_TAGBITS 0x07 /* All tag bits */ 1065 1066 #define TCPCB_EVER_RETRANS 0x80 /* Ever retransmitted frame */ 1067 #define TCPCB_RETRANS (TCPCB_SACKED_RETRANS|TCPCB_EVER_RETRANS) 1068 1069 #define TCPCB_URG 0x20 /* Urgent pointer advenced here */ 1070 1071 #define TCPCB_AT_TAIL (TCPCB_URG) 1072 1073 __u16 urg_ptr; /* Valid w/URG flags is set. */ 1074 __u32 ack_seq; /* Sequence number ACK'd */ 1075 }; 1076 1077 #define TCP_SKB_CB(__skb) ((struct tcp_skb_cb *)&((__skb)->cb[0])) 1078 1079 #include <net/tcp_ecn.h> 1080 1081 /* Due to TSO, an SKB can be composed of multiple actual 1082 * packets. To keep these tracked properly, we use this. 1083 */ 1084 static inline int tcp_skb_pcount(const struct sk_buff *skb) 1085 { 1086 return skb_shinfo(skb)->tso_segs; 1087 } 1088 1089 /* This is valid iff tcp_skb_pcount() > 1. */ 1090 static inline int tcp_skb_mss(const struct sk_buff *skb) 1091 { 1092 return skb_shinfo(skb)->tso_size; 1093 } 1094 1095 static inline void tcp_dec_pcount_approx(__u32 *count, 1096 const struct sk_buff *skb) 1097 { 1098 if (*count) { 1099 *count -= tcp_skb_pcount(skb); 1100 if ((int)*count < 0) 1101 *count = 0; 1102 } 1103 } 1104 1105 static inline void tcp_packets_out_inc(struct sock *sk, 1106 struct tcp_sock *tp, 1107 const struct sk_buff *skb) 1108 { 1109 int orig = tp->packets_out; 1110 1111 tp->packets_out += tcp_skb_pcount(skb); 1112 if (!orig) 1113 tcp_reset_xmit_timer(sk, TCP_TIME_RETRANS, tp->rto); 1114 } 1115 1116 static inline void tcp_packets_out_dec(struct tcp_sock *tp, 1117 const struct sk_buff *skb) 1118 { 1119 tp->packets_out -= tcp_skb_pcount(skb); 1120 } 1121 1122 /* Events passed to congestion control interface */ 1123 enum tcp_ca_event { 1124 CA_EVENT_TX_START, /* first transmit when no packets in flight */ 1125 CA_EVENT_CWND_RESTART, /* congestion window restart */ 1126 CA_EVENT_COMPLETE_CWR, /* end of congestion recovery */ 1127 CA_EVENT_FRTO, /* fast recovery timeout */ 1128 CA_EVENT_LOSS, /* loss timeout */ 1129 CA_EVENT_FAST_ACK, /* in sequence ack */ 1130 CA_EVENT_SLOW_ACK, /* other ack */ 1131 }; 1132 1133 /* 1134 * Interface for adding new TCP congestion control handlers 1135 */ 1136 #define TCP_CA_NAME_MAX 16 1137 struct tcp_congestion_ops { 1138 struct list_head list; 1139 1140 /* initialize private data (optional) */ 1141 void (*init)(struct tcp_sock *tp); 1142 /* cleanup private data (optional) */ 1143 void (*release)(struct tcp_sock *tp); 1144 1145 /* return slow start threshold (required) */ 1146 u32 (*ssthresh)(struct tcp_sock *tp); 1147 /* lower bound for congestion window (optional) */ 1148 u32 (*min_cwnd)(struct tcp_sock *tp); 1149 /* do new cwnd calculation (required) */ 1150 void (*cong_avoid)(struct tcp_sock *tp, u32 ack, 1151 u32 rtt, u32 in_flight, int good_ack); 1152 /* round trip time sample per acked packet (optional) */ 1153 void (*rtt_sample)(struct tcp_sock *tp, u32 usrtt); 1154 /* call before changing ca_state (optional) */ 1155 void (*set_state)(struct tcp_sock *tp, u8 new_state); 1156 /* call when cwnd event occurs (optional) */ 1157 void (*cwnd_event)(struct tcp_sock *tp, enum tcp_ca_event ev); 1158 /* new value of cwnd after loss (optional) */ 1159 u32 (*undo_cwnd)(struct tcp_sock *tp); 1160 /* hook for packet ack accounting (optional) */ 1161 void (*pkts_acked)(struct tcp_sock *tp, u32 num_acked); 1162 /* get info for tcp_diag (optional) */ 1163 void (*get_info)(struct tcp_sock *tp, u32 ext, struct sk_buff *skb); 1164 1165 char name[TCP_CA_NAME_MAX]; 1166 struct module *owner; 1167 }; 1168 1169 extern int tcp_register_congestion_control(struct tcp_congestion_ops *type); 1170 extern void tcp_unregister_congestion_control(struct tcp_congestion_ops *type); 1171 1172 extern void tcp_init_congestion_control(struct tcp_sock *tp); 1173 extern void tcp_cleanup_congestion_control(struct tcp_sock *tp); 1174 extern int tcp_set_default_congestion_control(const char *name); 1175 extern void tcp_get_default_congestion_control(char *name); 1176 extern int tcp_set_congestion_control(struct tcp_sock *tp, const char *name); 1177 1178 extern struct tcp_congestion_ops tcp_init_congestion_ops; 1179 extern u32 tcp_reno_ssthresh(struct tcp_sock *tp); 1180 extern void tcp_reno_cong_avoid(struct tcp_sock *tp, u32 ack, 1181 u32 rtt, u32 in_flight, int flag); 1182 extern u32 tcp_reno_min_cwnd(struct tcp_sock *tp); 1183 extern struct tcp_congestion_ops tcp_reno; 1184 1185 static inline void tcp_set_ca_state(struct tcp_sock *tp, u8 ca_state) 1186 { 1187 if (tp->ca_ops->set_state) 1188 tp->ca_ops->set_state(tp, ca_state); 1189 tp->ca_state = ca_state; 1190 } 1191 1192 static inline void tcp_ca_event(struct tcp_sock *tp, enum tcp_ca_event event) 1193 { 1194 if (tp->ca_ops->cwnd_event) 1195 tp->ca_ops->cwnd_event(tp, event); 1196 } 1197 1198 /* This determines how many packets are "in the network" to the best 1199 * of our knowledge. In many cases it is conservative, but where 1200 * detailed information is available from the receiver (via SACK 1201 * blocks etc.) we can make more aggressive calculations. 1202 * 1203 * Use this for decisions involving congestion control, use just 1204 * tp->packets_out to determine if the send queue is empty or not. 1205 * 1206 * Read this equation as: 1207 * 1208 * "Packets sent once on transmission queue" MINUS 1209 * "Packets left network, but not honestly ACKed yet" PLUS 1210 * "Packets fast retransmitted" 1211 */ 1212 static __inline__ unsigned int tcp_packets_in_flight(const struct tcp_sock *tp) 1213 { 1214 return (tp->packets_out - tp->left_out + tp->retrans_out); 1215 } 1216 1217 /* If cwnd > ssthresh, we may raise ssthresh to be half-way to cwnd. 1218 * The exception is rate halving phase, when cwnd is decreasing towards 1219 * ssthresh. 1220 */ 1221 static inline __u32 tcp_current_ssthresh(struct tcp_sock *tp) 1222 { 1223 if ((1<<tp->ca_state)&(TCPF_CA_CWR|TCPF_CA_Recovery)) 1224 return tp->snd_ssthresh; 1225 else 1226 return max(tp->snd_ssthresh, 1227 ((tp->snd_cwnd >> 1) + 1228 (tp->snd_cwnd >> 2))); 1229 } 1230 1231 static inline void tcp_sync_left_out(struct tcp_sock *tp) 1232 { 1233 if (tp->rx_opt.sack_ok && 1234 (tp->sacked_out >= tp->packets_out - tp->lost_out)) 1235 tp->sacked_out = tp->packets_out - tp->lost_out; 1236 tp->left_out = tp->sacked_out + tp->lost_out; 1237 } 1238 1239 /* Set slow start threshould and cwnd not falling to slow start */ 1240 static inline void __tcp_enter_cwr(struct tcp_sock *tp) 1241 { 1242 tp->undo_marker = 0; 1243 tp->snd_ssthresh = tp->ca_ops->ssthresh(tp); 1244 tp->snd_cwnd = min(tp->snd_cwnd, 1245 tcp_packets_in_flight(tp) + 1U); 1246 tp->snd_cwnd_cnt = 0; 1247 tp->high_seq = tp->snd_nxt; 1248 tp->snd_cwnd_stamp = tcp_time_stamp; 1249 TCP_ECN_queue_cwr(tp); 1250 } 1251 1252 static inline void tcp_enter_cwr(struct tcp_sock *tp) 1253 { 1254 tp->prior_ssthresh = 0; 1255 if (tp->ca_state < TCP_CA_CWR) { 1256 __tcp_enter_cwr(tp); 1257 tcp_set_ca_state(tp, TCP_CA_CWR); 1258 } 1259 } 1260 1261 extern __u32 tcp_init_cwnd(struct tcp_sock *tp, struct dst_entry *dst); 1262 1263 /* Slow start with delack produces 3 packets of burst, so that 1264 * it is safe "de facto". 1265 */ 1266 static __inline__ __u32 tcp_max_burst(const struct tcp_sock *tp) 1267 { 1268 return 3; 1269 } 1270 1271 static __inline__ void tcp_minshall_update(struct tcp_sock *tp, int mss, 1272 const struct sk_buff *skb) 1273 { 1274 if (skb->len < mss) 1275 tp->snd_sml = TCP_SKB_CB(skb)->end_seq; 1276 } 1277 1278 static __inline__ void tcp_check_probe_timer(struct sock *sk, struct tcp_sock *tp) 1279 { 1280 if (!tp->packets_out && !tp->pending) 1281 tcp_reset_xmit_timer(sk, TCP_TIME_PROBE0, tp->rto); 1282 } 1283 1284 static __inline__ void tcp_push_pending_frames(struct sock *sk, 1285 struct tcp_sock *tp) 1286 { 1287 __tcp_push_pending_frames(sk, tp, tcp_current_mss(sk, 1), tp->nonagle); 1288 } 1289 1290 static __inline__ void tcp_init_wl(struct tcp_sock *tp, u32 ack, u32 seq) 1291 { 1292 tp->snd_wl1 = seq; 1293 } 1294 1295 static __inline__ void tcp_update_wl(struct tcp_sock *tp, u32 ack, u32 seq) 1296 { 1297 tp->snd_wl1 = seq; 1298 } 1299 1300 extern void tcp_destroy_sock(struct sock *sk); 1301 1302 1303 /* 1304 * Calculate(/check) TCP checksum 1305 */ 1306 static __inline__ u16 tcp_v4_check(struct tcphdr *th, int len, 1307 unsigned long saddr, unsigned long daddr, 1308 unsigned long base) 1309 { 1310 return csum_tcpudp_magic(saddr,daddr,len,IPPROTO_TCP,base); 1311 } 1312 1313 static __inline__ int __tcp_checksum_complete(struct sk_buff *skb) 1314 { 1315 return (unsigned short)csum_fold(skb_checksum(skb, 0, skb->len, skb->csum)); 1316 } 1317 1318 static __inline__ int tcp_checksum_complete(struct sk_buff *skb) 1319 { 1320 return skb->ip_summed != CHECKSUM_UNNECESSARY && 1321 __tcp_checksum_complete(skb); 1322 } 1323 1324 /* Prequeue for VJ style copy to user, combined with checksumming. */ 1325 1326 static __inline__ void tcp_prequeue_init(struct tcp_sock *tp) 1327 { 1328 tp->ucopy.task = NULL; 1329 tp->ucopy.len = 0; 1330 tp->ucopy.memory = 0; 1331 skb_queue_head_init(&tp->ucopy.prequeue); 1332 } 1333 1334 /* Packet is added to VJ-style prequeue for processing in process 1335 * context, if a reader task is waiting. Apparently, this exciting 1336 * idea (VJ's mail "Re: query about TCP header on tcp-ip" of 07 Sep 93) 1337 * failed somewhere. Latency? Burstiness? Well, at least now we will 1338 * see, why it failed. 8)8) --ANK 1339 * 1340 * NOTE: is this not too big to inline? 1341 */ 1342 static __inline__ int tcp_prequeue(struct sock *sk, struct sk_buff *skb) 1343 { 1344 struct tcp_sock *tp = tcp_sk(sk); 1345 1346 if (!sysctl_tcp_low_latency && tp->ucopy.task) { 1347 __skb_queue_tail(&tp->ucopy.prequeue, skb); 1348 tp->ucopy.memory += skb->truesize; 1349 if (tp->ucopy.memory > sk->sk_rcvbuf) { 1350 struct sk_buff *skb1; 1351 1352 BUG_ON(sock_owned_by_user(sk)); 1353 1354 while ((skb1 = __skb_dequeue(&tp->ucopy.prequeue)) != NULL) { 1355 sk->sk_backlog_rcv(sk, skb1); 1356 NET_INC_STATS_BH(LINUX_MIB_TCPPREQUEUEDROPPED); 1357 } 1358 1359 tp->ucopy.memory = 0; 1360 } else if (skb_queue_len(&tp->ucopy.prequeue) == 1) { 1361 wake_up_interruptible(sk->sk_sleep); 1362 if (!tcp_ack_scheduled(tp)) 1363 tcp_reset_xmit_timer(sk, TCP_TIME_DACK, (3*TCP_RTO_MIN)/4); 1364 } 1365 return 1; 1366 } 1367 return 0; 1368 } 1369 1370 1371 #undef STATE_TRACE 1372 1373 #ifdef STATE_TRACE 1374 static const char *statename[]={ 1375 "Unused","Established","Syn Sent","Syn Recv", 1376 "Fin Wait 1","Fin Wait 2","Time Wait", "Close", 1377 "Close Wait","Last ACK","Listen","Closing" 1378 }; 1379 #endif 1380 1381 static __inline__ void tcp_set_state(struct sock *sk, int state) 1382 { 1383 int oldstate = sk->sk_state; 1384 1385 switch (state) { 1386 case TCP_ESTABLISHED: 1387 if (oldstate != TCP_ESTABLISHED) 1388 TCP_INC_STATS(TCP_MIB_CURRESTAB); 1389 break; 1390 1391 case TCP_CLOSE: 1392 if (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED) 1393 TCP_INC_STATS(TCP_MIB_ESTABRESETS); 1394 1395 sk->sk_prot->unhash(sk); 1396 if (tcp_sk(sk)->bind_hash && 1397 !(sk->sk_userlocks & SOCK_BINDPORT_LOCK)) 1398 tcp_put_port(sk); 1399 /* fall through */ 1400 default: 1401 if (oldstate==TCP_ESTABLISHED) 1402 TCP_DEC_STATS(TCP_MIB_CURRESTAB); 1403 } 1404 1405 /* Change state AFTER socket is unhashed to avoid closed 1406 * socket sitting in hash tables. 1407 */ 1408 sk->sk_state = state; 1409 1410 #ifdef STATE_TRACE 1411 SOCK_DEBUG(sk, "TCP sk=%p, State %s -> %s\n",sk, statename[oldstate],statename[state]); 1412 #endif 1413 } 1414 1415 static __inline__ void tcp_done(struct sock *sk) 1416 { 1417 tcp_set_state(sk, TCP_CLOSE); 1418 tcp_clear_xmit_timers(sk); 1419 1420 sk->sk_shutdown = SHUTDOWN_MASK; 1421 1422 if (!sock_flag(sk, SOCK_DEAD)) 1423 sk->sk_state_change(sk); 1424 else 1425 tcp_destroy_sock(sk); 1426 } 1427 1428 static __inline__ void tcp_sack_reset(struct tcp_options_received *rx_opt) 1429 { 1430 rx_opt->dsack = 0; 1431 rx_opt->eff_sacks = 0; 1432 rx_opt->num_sacks = 0; 1433 } 1434 1435 static __inline__ void tcp_build_and_update_options(__u32 *ptr, struct tcp_sock *tp, __u32 tstamp) 1436 { 1437 if (tp->rx_opt.tstamp_ok) { 1438 *ptr++ = __constant_htonl((TCPOPT_NOP << 24) | 1439 (TCPOPT_NOP << 16) | 1440 (TCPOPT_TIMESTAMP << 8) | 1441 TCPOLEN_TIMESTAMP); 1442 *ptr++ = htonl(tstamp); 1443 *ptr++ = htonl(tp->rx_opt.ts_recent); 1444 } 1445 if (tp->rx_opt.eff_sacks) { 1446 struct tcp_sack_block *sp = tp->rx_opt.dsack ? tp->duplicate_sack : tp->selective_acks; 1447 int this_sack; 1448 1449 *ptr++ = __constant_htonl((TCPOPT_NOP << 24) | 1450 (TCPOPT_NOP << 16) | 1451 (TCPOPT_SACK << 8) | 1452 (TCPOLEN_SACK_BASE + 1453 (tp->rx_opt.eff_sacks * TCPOLEN_SACK_PERBLOCK))); 1454 for(this_sack = 0; this_sack < tp->rx_opt.eff_sacks; this_sack++) { 1455 *ptr++ = htonl(sp[this_sack].start_seq); 1456 *ptr++ = htonl(sp[this_sack].end_seq); 1457 } 1458 if (tp->rx_opt.dsack) { 1459 tp->rx_opt.dsack = 0; 1460 tp->rx_opt.eff_sacks--; 1461 } 1462 } 1463 } 1464 1465 /* Construct a tcp options header for a SYN or SYN_ACK packet. 1466 * If this is every changed make sure to change the definition of 1467 * MAX_SYN_SIZE to match the new maximum number of options that you 1468 * can generate. 1469 */ 1470 static inline void tcp_syn_build_options(__u32 *ptr, int mss, int ts, int sack, 1471 int offer_wscale, int wscale, __u32 tstamp, __u32 ts_recent) 1472 { 1473 /* We always get an MSS option. 1474 * The option bytes which will be seen in normal data 1475 * packets should timestamps be used, must be in the MSS 1476 * advertised. But we subtract them from tp->mss_cache so 1477 * that calculations in tcp_sendmsg are simpler etc. 1478 * So account for this fact here if necessary. If we 1479 * don't do this correctly, as a receiver we won't 1480 * recognize data packets as being full sized when we 1481 * should, and thus we won't abide by the delayed ACK 1482 * rules correctly. 1483 * SACKs don't matter, we never delay an ACK when we 1484 * have any of those going out. 1485 */ 1486 *ptr++ = htonl((TCPOPT_MSS << 24) | (TCPOLEN_MSS << 16) | mss); 1487 if (ts) { 1488 if(sack) 1489 *ptr++ = __constant_htonl((TCPOPT_SACK_PERM << 24) | (TCPOLEN_SACK_PERM << 16) | 1490 (TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP); 1491 else 1492 *ptr++ = __constant_htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) | 1493 (TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP); 1494 *ptr++ = htonl(tstamp); /* TSVAL */ 1495 *ptr++ = htonl(ts_recent); /* TSECR */ 1496 } else if(sack) 1497 *ptr++ = __constant_htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) | 1498 (TCPOPT_SACK_PERM << 8) | TCPOLEN_SACK_PERM); 1499 if (offer_wscale) 1500 *ptr++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_WINDOW << 16) | (TCPOLEN_WINDOW << 8) | (wscale)); 1501 } 1502 1503 /* Determine a window scaling and initial window to offer. */ 1504 extern void tcp_select_initial_window(int __space, __u32 mss, 1505 __u32 *rcv_wnd, __u32 *window_clamp, 1506 int wscale_ok, __u8 *rcv_wscale); 1507 1508 static inline int tcp_win_from_space(int space) 1509 { 1510 return sysctl_tcp_adv_win_scale<=0 ? 1511 (space>>(-sysctl_tcp_adv_win_scale)) : 1512 space - (space>>sysctl_tcp_adv_win_scale); 1513 } 1514 1515 /* Note: caller must be prepared to deal with negative returns */ 1516 static inline int tcp_space(const struct sock *sk) 1517 { 1518 return tcp_win_from_space(sk->sk_rcvbuf - 1519 atomic_read(&sk->sk_rmem_alloc)); 1520 } 1521 1522 static inline int tcp_full_space(const struct sock *sk) 1523 { 1524 return tcp_win_from_space(sk->sk_rcvbuf); 1525 } 1526 1527 static inline void tcp_acceptq_queue(struct sock *sk, struct request_sock *req, 1528 struct sock *child) 1529 { 1530 reqsk_queue_add(&tcp_sk(sk)->accept_queue, req, sk, child); 1531 } 1532 1533 static inline void 1534 tcp_synq_removed(struct sock *sk, struct request_sock *req) 1535 { 1536 if (reqsk_queue_removed(&tcp_sk(sk)->accept_queue, req) == 0) 1537 tcp_delete_keepalive_timer(sk); 1538 } 1539 1540 static inline void tcp_synq_added(struct sock *sk) 1541 { 1542 if (reqsk_queue_added(&tcp_sk(sk)->accept_queue) == 0) 1543 tcp_reset_keepalive_timer(sk, TCP_TIMEOUT_INIT); 1544 } 1545 1546 static inline int tcp_synq_len(struct sock *sk) 1547 { 1548 return reqsk_queue_len(&tcp_sk(sk)->accept_queue); 1549 } 1550 1551 static inline int tcp_synq_young(struct sock *sk) 1552 { 1553 return reqsk_queue_len_young(&tcp_sk(sk)->accept_queue); 1554 } 1555 1556 static inline int tcp_synq_is_full(struct sock *sk) 1557 { 1558 return reqsk_queue_is_full(&tcp_sk(sk)->accept_queue); 1559 } 1560 1561 static inline void tcp_synq_unlink(struct tcp_sock *tp, struct request_sock *req, 1562 struct request_sock **prev) 1563 { 1564 reqsk_queue_unlink(&tp->accept_queue, req, prev); 1565 } 1566 1567 static inline void tcp_synq_drop(struct sock *sk, struct request_sock *req, 1568 struct request_sock **prev) 1569 { 1570 tcp_synq_unlink(tcp_sk(sk), req, prev); 1571 tcp_synq_removed(sk, req); 1572 reqsk_free(req); 1573 } 1574 1575 static __inline__ void tcp_openreq_init(struct request_sock *req, 1576 struct tcp_options_received *rx_opt, 1577 struct sk_buff *skb) 1578 { 1579 struct inet_request_sock *ireq = inet_rsk(req); 1580 1581 req->rcv_wnd = 0; /* So that tcp_send_synack() knows! */ 1582 tcp_rsk(req)->rcv_isn = TCP_SKB_CB(skb)->seq; 1583 req->mss = rx_opt->mss_clamp; 1584 req->ts_recent = rx_opt->saw_tstamp ? rx_opt->rcv_tsval : 0; 1585 ireq->tstamp_ok = rx_opt->tstamp_ok; 1586 ireq->sack_ok = rx_opt->sack_ok; 1587 ireq->snd_wscale = rx_opt->snd_wscale; 1588 ireq->wscale_ok = rx_opt->wscale_ok; 1589 ireq->acked = 0; 1590 ireq->ecn_ok = 0; 1591 ireq->rmt_port = skb->h.th->source; 1592 } 1593 1594 extern void tcp_enter_memory_pressure(void); 1595 1596 extern void tcp_listen_wlock(void); 1597 1598 /* - We may sleep inside this lock. 1599 * - If sleeping is not required (or called from BH), 1600 * use plain read_(un)lock(&tcp_lhash_lock). 1601 */ 1602 1603 static inline void tcp_listen_lock(void) 1604 { 1605 /* read_lock synchronizes to candidates to writers */ 1606 read_lock(&tcp_lhash_lock); 1607 atomic_inc(&tcp_lhash_users); 1608 read_unlock(&tcp_lhash_lock); 1609 } 1610 1611 static inline void tcp_listen_unlock(void) 1612 { 1613 if (atomic_dec_and_test(&tcp_lhash_users)) 1614 wake_up(&tcp_lhash_wait); 1615 } 1616 1617 static inline int keepalive_intvl_when(const struct tcp_sock *tp) 1618 { 1619 return tp->keepalive_intvl ? : sysctl_tcp_keepalive_intvl; 1620 } 1621 1622 static inline int keepalive_time_when(const struct tcp_sock *tp) 1623 { 1624 return tp->keepalive_time ? : sysctl_tcp_keepalive_time; 1625 } 1626 1627 static inline int tcp_fin_time(const struct tcp_sock *tp) 1628 { 1629 int fin_timeout = tp->linger2 ? : sysctl_tcp_fin_timeout; 1630 1631 if (fin_timeout < (tp->rto<<2) - (tp->rto>>1)) 1632 fin_timeout = (tp->rto<<2) - (tp->rto>>1); 1633 1634 return fin_timeout; 1635 } 1636 1637 static inline int tcp_paws_check(const struct tcp_options_received *rx_opt, int rst) 1638 { 1639 if ((s32)(rx_opt->rcv_tsval - rx_opt->ts_recent) >= 0) 1640 return 0; 1641 if (xtime.tv_sec >= rx_opt->ts_recent_stamp + TCP_PAWS_24DAYS) 1642 return 0; 1643 1644 /* RST segments are not recommended to carry timestamp, 1645 and, if they do, it is recommended to ignore PAWS because 1646 "their cleanup function should take precedence over timestamps." 1647 Certainly, it is mistake. It is necessary to understand the reasons 1648 of this constraint to relax it: if peer reboots, clock may go 1649 out-of-sync and half-open connections will not be reset. 1650 Actually, the problem would be not existing if all 1651 the implementations followed draft about maintaining clock 1652 via reboots. Linux-2.2 DOES NOT! 1653 1654 However, we can relax time bounds for RST segments to MSL. 1655 */ 1656 if (rst && xtime.tv_sec >= rx_opt->ts_recent_stamp + TCP_PAWS_MSL) 1657 return 0; 1658 return 1; 1659 } 1660 1661 static inline void tcp_v4_setup_caps(struct sock *sk, struct dst_entry *dst) 1662 { 1663 sk->sk_route_caps = dst->dev->features; 1664 if (sk->sk_route_caps & NETIF_F_TSO) { 1665 if (sock_flag(sk, SOCK_NO_LARGESEND) || dst->header_len) 1666 sk->sk_route_caps &= ~NETIF_F_TSO; 1667 } 1668 } 1669 1670 #define TCP_CHECK_TIMER(sk) do { } while (0) 1671 1672 static inline int tcp_use_frto(const struct sock *sk) 1673 { 1674 const struct tcp_sock *tp = tcp_sk(sk); 1675 1676 /* F-RTO must be activated in sysctl and there must be some 1677 * unsent new data, and the advertised window should allow 1678 * sending it. 1679 */ 1680 return (sysctl_tcp_frto && sk->sk_send_head && 1681 !after(TCP_SKB_CB(sk->sk_send_head)->end_seq, 1682 tp->snd_una + tp->snd_wnd)); 1683 } 1684 1685 static inline void tcp_mib_init(void) 1686 { 1687 /* See RFC 2012 */ 1688 TCP_ADD_STATS_USER(TCP_MIB_RTOALGORITHM, 1); 1689 TCP_ADD_STATS_USER(TCP_MIB_RTOMIN, TCP_RTO_MIN*1000/HZ); 1690 TCP_ADD_STATS_USER(TCP_MIB_RTOMAX, TCP_RTO_MAX*1000/HZ); 1691 TCP_ADD_STATS_USER(TCP_MIB_MAXCONN, -1); 1692 } 1693 1694 /* /proc */ 1695 enum tcp_seq_states { 1696 TCP_SEQ_STATE_LISTENING, 1697 TCP_SEQ_STATE_OPENREQ, 1698 TCP_SEQ_STATE_ESTABLISHED, 1699 TCP_SEQ_STATE_TIME_WAIT, 1700 }; 1701 1702 struct tcp_seq_afinfo { 1703 struct module *owner; 1704 char *name; 1705 sa_family_t family; 1706 int (*seq_show) (struct seq_file *m, void *v); 1707 struct file_operations *seq_fops; 1708 }; 1709 1710 struct tcp_iter_state { 1711 sa_family_t family; 1712 enum tcp_seq_states state; 1713 struct sock *syn_wait_sk; 1714 int bucket, sbucket, num, uid; 1715 struct seq_operations seq_ops; 1716 }; 1717 1718 extern int tcp_proc_register(struct tcp_seq_afinfo *afinfo); 1719 extern void tcp_proc_unregister(struct tcp_seq_afinfo *afinfo); 1720 1721 #endif /* _TCP_H */ 1722