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 #include <linux/config.h> 25 #include <linux/list.h> 26 #include <linux/tcp.h> 27 #include <linux/slab.h> 28 #include <linux/cache.h> 29 #include <linux/percpu.h> 30 31 #include <net/inet_connection_sock.h> 32 #include <net/inet_timewait_sock.h> 33 #include <net/inet_hashtables.h> 34 #include <net/checksum.h> 35 #include <net/request_sock.h> 36 #include <net/sock.h> 37 #include <net/snmp.h> 38 #include <net/ip.h> 39 #include <net/tcp_states.h> 40 41 #include <linux/seq_file.h> 42 43 extern struct inet_hashinfo tcp_hashinfo; 44 45 extern atomic_t tcp_orphan_count; 46 extern void tcp_time_wait(struct sock *sk, int state, int timeo); 47 48 #define MAX_TCP_HEADER (128 + MAX_HEADER) 49 50 /* 51 * Never offer a window over 32767 without using window scaling. Some 52 * poor stacks do signed 16bit maths! 53 */ 54 #define MAX_TCP_WINDOW 32767U 55 56 /* Minimal accepted MSS. It is (60+60+8) - (20+20). */ 57 #define TCP_MIN_MSS 88U 58 59 /* Minimal RCV_MSS. */ 60 #define TCP_MIN_RCVMSS 536U 61 62 /* After receiving this amount of duplicate ACKs fast retransmit starts. */ 63 #define TCP_FASTRETRANS_THRESH 3 64 65 /* Maximal reordering. */ 66 #define TCP_MAX_REORDERING 127 67 68 /* Maximal number of ACKs sent quickly to accelerate slow-start. */ 69 #define TCP_MAX_QUICKACKS 16U 70 71 /* urg_data states */ 72 #define TCP_URG_VALID 0x0100 73 #define TCP_URG_NOTYET 0x0200 74 #define TCP_URG_READ 0x0400 75 76 #define TCP_RETR1 3 /* 77 * This is how many retries it does before it 78 * tries to figure out if the gateway is 79 * down. Minimal RFC value is 3; it corresponds 80 * to ~3sec-8min depending on RTO. 81 */ 82 83 #define TCP_RETR2 15 /* 84 * This should take at least 85 * 90 minutes to time out. 86 * RFC1122 says that the limit is 100 sec. 87 * 15 is ~13-30min depending on RTO. 88 */ 89 90 #define TCP_SYN_RETRIES 5 /* number of times to retry active opening a 91 * connection: ~180sec is RFC minumum */ 92 93 #define TCP_SYNACK_RETRIES 5 /* number of times to retry passive opening a 94 * connection: ~180sec is RFC minumum */ 95 96 97 #define TCP_ORPHAN_RETRIES 7 /* number of times to retry on an orphaned 98 * socket. 7 is ~50sec-16min. 99 */ 100 101 102 #define TCP_TIMEWAIT_LEN (60*HZ) /* how long to wait to destroy TIME-WAIT 103 * state, about 60 seconds */ 104 #define TCP_FIN_TIMEOUT TCP_TIMEWAIT_LEN 105 /* BSD style FIN_WAIT2 deadlock breaker. 106 * It used to be 3min, new value is 60sec, 107 * to combine FIN-WAIT-2 timeout with 108 * TIME-WAIT timer. 109 */ 110 111 #define TCP_DELACK_MAX ((unsigned)(HZ/5)) /* maximal time to delay before sending an ACK */ 112 #if HZ >= 100 113 #define TCP_DELACK_MIN ((unsigned)(HZ/25)) /* minimal time to delay before sending an ACK */ 114 #define TCP_ATO_MIN ((unsigned)(HZ/25)) 115 #else 116 #define TCP_DELACK_MIN 4U 117 #define TCP_ATO_MIN 4U 118 #endif 119 #define TCP_RTO_MAX ((unsigned)(120*HZ)) 120 #define TCP_RTO_MIN ((unsigned)(HZ/5)) 121 #define TCP_TIMEOUT_INIT ((unsigned)(3*HZ)) /* RFC 1122 initial RTO value */ 122 123 #define TCP_RESOURCE_PROBE_INTERVAL ((unsigned)(HZ/2U)) /* Maximal interval between probes 124 * for local resources. 125 */ 126 127 #define TCP_KEEPALIVE_TIME (120*60*HZ) /* two hours */ 128 #define TCP_KEEPALIVE_PROBES 9 /* Max of 9 keepalive probes */ 129 #define TCP_KEEPALIVE_INTVL (75*HZ) 130 131 #define MAX_TCP_KEEPIDLE 32767 132 #define MAX_TCP_KEEPINTVL 32767 133 #define MAX_TCP_KEEPCNT 127 134 #define MAX_TCP_SYNCNT 127 135 136 #define TCP_SYNQ_INTERVAL (HZ/5) /* Period of SYNACK timer */ 137 #define TCP_SYNQ_HSIZE 512 /* Size of SYNACK hash table */ 138 139 #define TCP_PAWS_24DAYS (60 * 60 * 24 * 24) 140 #define TCP_PAWS_MSL 60 /* Per-host timestamps are invalidated 141 * after this time. It should be equal 142 * (or greater than) TCP_TIMEWAIT_LEN 143 * to provide reliability equal to one 144 * provided by timewait state. 145 */ 146 #define TCP_PAWS_WINDOW 1 /* Replay window for per-host 147 * timestamps. It must be less than 148 * minimal timewait lifetime. 149 */ 150 /* 151 * TCP option 152 */ 153 154 #define TCPOPT_NOP 1 /* Padding */ 155 #define TCPOPT_EOL 0 /* End of options */ 156 #define TCPOPT_MSS 2 /* Segment size negotiating */ 157 #define TCPOPT_WINDOW 3 /* Window scaling */ 158 #define TCPOPT_SACK_PERM 4 /* SACK Permitted */ 159 #define TCPOPT_SACK 5 /* SACK Block */ 160 #define TCPOPT_TIMESTAMP 8 /* Better RTT estimations/PAWS */ 161 162 /* 163 * TCP option lengths 164 */ 165 166 #define TCPOLEN_MSS 4 167 #define TCPOLEN_WINDOW 3 168 #define TCPOLEN_SACK_PERM 2 169 #define TCPOLEN_TIMESTAMP 10 170 171 /* But this is what stacks really send out. */ 172 #define TCPOLEN_TSTAMP_ALIGNED 12 173 #define TCPOLEN_WSCALE_ALIGNED 4 174 #define TCPOLEN_SACKPERM_ALIGNED 4 175 #define TCPOLEN_SACK_BASE 2 176 #define TCPOLEN_SACK_BASE_ALIGNED 4 177 #define TCPOLEN_SACK_PERBLOCK 8 178 179 /* Flags in tp->nonagle */ 180 #define TCP_NAGLE_OFF 1 /* Nagle's algo is disabled */ 181 #define TCP_NAGLE_CORK 2 /* Socket is corked */ 182 #define TCP_NAGLE_PUSH 4 /* Cork is overriden for already queued data */ 183 184 extern struct inet_timewait_death_row tcp_death_row; 185 186 /* sysctl variables for tcp */ 187 extern int sysctl_tcp_timestamps; 188 extern int sysctl_tcp_window_scaling; 189 extern int sysctl_tcp_sack; 190 extern int sysctl_tcp_fin_timeout; 191 extern int sysctl_tcp_keepalive_time; 192 extern int sysctl_tcp_keepalive_probes; 193 extern int sysctl_tcp_keepalive_intvl; 194 extern int sysctl_tcp_syn_retries; 195 extern int sysctl_tcp_synack_retries; 196 extern int sysctl_tcp_retries1; 197 extern int sysctl_tcp_retries2; 198 extern int sysctl_tcp_orphan_retries; 199 extern int sysctl_tcp_syncookies; 200 extern int sysctl_tcp_retrans_collapse; 201 extern int sysctl_tcp_stdurg; 202 extern int sysctl_tcp_rfc1337; 203 extern int sysctl_tcp_abort_on_overflow; 204 extern int sysctl_tcp_max_orphans; 205 extern int sysctl_tcp_fack; 206 extern int sysctl_tcp_reordering; 207 extern int sysctl_tcp_ecn; 208 extern int sysctl_tcp_dsack; 209 extern int sysctl_tcp_mem[3]; 210 extern int sysctl_tcp_wmem[3]; 211 extern int sysctl_tcp_rmem[3]; 212 extern int sysctl_tcp_app_win; 213 extern int sysctl_tcp_adv_win_scale; 214 extern int sysctl_tcp_tw_reuse; 215 extern int sysctl_tcp_frto; 216 extern int sysctl_tcp_low_latency; 217 extern int sysctl_tcp_nometrics_save; 218 extern int sysctl_tcp_moderate_rcvbuf; 219 extern int sysctl_tcp_tso_win_divisor; 220 221 extern atomic_t tcp_memory_allocated; 222 extern atomic_t tcp_sockets_allocated; 223 extern int tcp_memory_pressure; 224 225 /* 226 * Pointers to address related TCP functions 227 * (i.e. things that depend on the address family) 228 */ 229 230 struct tcp_func { 231 int (*queue_xmit) (struct sk_buff *skb, 232 int ipfragok); 233 234 void (*send_check) (struct sock *sk, 235 struct tcphdr *th, 236 int len, 237 struct sk_buff *skb); 238 239 int (*rebuild_header) (struct sock *sk); 240 241 int (*conn_request) (struct sock *sk, 242 struct sk_buff *skb); 243 244 struct sock * (*syn_recv_sock) (struct sock *sk, 245 struct sk_buff *skb, 246 struct request_sock *req, 247 struct dst_entry *dst); 248 249 int (*remember_stamp) (struct sock *sk); 250 251 __u16 net_header_len; 252 253 int (*setsockopt) (struct sock *sk, 254 int level, 255 int optname, 256 char __user *optval, 257 int optlen); 258 259 int (*getsockopt) (struct sock *sk, 260 int level, 261 int optname, 262 char __user *optval, 263 int __user *optlen); 264 265 266 void (*addr2sockaddr) (struct sock *sk, 267 struct sockaddr *); 268 269 int sockaddr_len; 270 }; 271 272 /* 273 * The next routines deal with comparing 32 bit unsigned ints 274 * and worry about wraparound (automatic with unsigned arithmetic). 275 */ 276 277 static inline int before(__u32 seq1, __u32 seq2) 278 { 279 return (__s32)(seq1-seq2) < 0; 280 } 281 282 static inline int after(__u32 seq1, __u32 seq2) 283 { 284 return (__s32)(seq2-seq1) < 0; 285 } 286 287 288 /* is s2<=s1<=s3 ? */ 289 static inline int between(__u32 seq1, __u32 seq2, __u32 seq3) 290 { 291 return seq3 - seq2 >= seq1 - seq2; 292 } 293 294 295 extern struct proto tcp_prot; 296 297 DECLARE_SNMP_STAT(struct tcp_mib, tcp_statistics); 298 #define TCP_INC_STATS(field) SNMP_INC_STATS(tcp_statistics, field) 299 #define TCP_INC_STATS_BH(field) SNMP_INC_STATS_BH(tcp_statistics, field) 300 #define TCP_INC_STATS_USER(field) SNMP_INC_STATS_USER(tcp_statistics, field) 301 #define TCP_DEC_STATS(field) SNMP_DEC_STATS(tcp_statistics, field) 302 #define TCP_ADD_STATS_BH(field, val) SNMP_ADD_STATS_BH(tcp_statistics, field, val) 303 #define TCP_ADD_STATS_USER(field, val) SNMP_ADD_STATS_USER(tcp_statistics, field, val) 304 305 extern void tcp_v4_err(struct sk_buff *skb, u32); 306 307 extern void tcp_shutdown (struct sock *sk, int how); 308 309 extern int tcp_v4_rcv(struct sk_buff *skb); 310 311 extern int tcp_v4_remember_stamp(struct sock *sk); 312 313 extern int tcp_v4_tw_remember_stamp(struct inet_timewait_sock *tw); 314 315 extern int tcp_sendmsg(struct kiocb *iocb, struct sock *sk, 316 struct msghdr *msg, size_t size); 317 extern ssize_t tcp_sendpage(struct socket *sock, struct page *page, int offset, size_t size, int flags); 318 319 extern int tcp_ioctl(struct sock *sk, 320 int cmd, 321 unsigned long arg); 322 323 extern int tcp_rcv_state_process(struct sock *sk, 324 struct sk_buff *skb, 325 struct tcphdr *th, 326 unsigned len); 327 328 extern int tcp_rcv_established(struct sock *sk, 329 struct sk_buff *skb, 330 struct tcphdr *th, 331 unsigned len); 332 333 extern void tcp_rcv_space_adjust(struct sock *sk); 334 335 static inline void tcp_dec_quickack_mode(struct sock *sk, 336 const unsigned int pkts) 337 { 338 struct inet_connection_sock *icsk = inet_csk(sk); 339 340 if (icsk->icsk_ack.quick) { 341 if (pkts >= icsk->icsk_ack.quick) { 342 icsk->icsk_ack.quick = 0; 343 /* Leaving quickack mode we deflate ATO. */ 344 icsk->icsk_ack.ato = TCP_ATO_MIN; 345 } else 346 icsk->icsk_ack.quick -= pkts; 347 } 348 } 349 350 extern void tcp_enter_quickack_mode(struct sock *sk); 351 352 static inline void tcp_clear_options(struct tcp_options_received *rx_opt) 353 { 354 rx_opt->tstamp_ok = rx_opt->sack_ok = rx_opt->wscale_ok = rx_opt->snd_wscale = 0; 355 } 356 357 enum tcp_tw_status 358 { 359 TCP_TW_SUCCESS = 0, 360 TCP_TW_RST = 1, 361 TCP_TW_ACK = 2, 362 TCP_TW_SYN = 3 363 }; 364 365 366 extern enum tcp_tw_status tcp_timewait_state_process(struct inet_timewait_sock *tw, 367 struct sk_buff *skb, 368 const struct tcphdr *th); 369 370 extern struct sock * tcp_check_req(struct sock *sk,struct sk_buff *skb, 371 struct request_sock *req, 372 struct request_sock **prev); 373 extern int tcp_child_process(struct sock *parent, 374 struct sock *child, 375 struct sk_buff *skb); 376 extern void tcp_enter_frto(struct sock *sk); 377 extern void tcp_enter_loss(struct sock *sk, int how); 378 extern void tcp_clear_retrans(struct tcp_sock *tp); 379 extern void tcp_update_metrics(struct sock *sk); 380 381 extern void tcp_close(struct sock *sk, 382 long timeout); 383 extern unsigned int tcp_poll(struct file * file, struct socket *sock, struct poll_table_struct *wait); 384 385 extern int tcp_getsockopt(struct sock *sk, int level, 386 int optname, 387 char __user *optval, 388 int __user *optlen); 389 extern int tcp_setsockopt(struct sock *sk, int level, 390 int optname, char __user *optval, 391 int optlen); 392 extern void tcp_set_keepalive(struct sock *sk, int val); 393 extern int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, 394 struct msghdr *msg, 395 size_t len, int nonblock, 396 int flags, int *addr_len); 397 398 extern void tcp_parse_options(struct sk_buff *skb, 399 struct tcp_options_received *opt_rx, 400 int estab); 401 402 /* 403 * TCP v4 functions exported for the inet6 API 404 */ 405 406 extern void tcp_v4_send_check(struct sock *sk, 407 struct tcphdr *th, int len, 408 struct sk_buff *skb); 409 410 extern int tcp_v4_conn_request(struct sock *sk, 411 struct sk_buff *skb); 412 413 extern struct sock * tcp_create_openreq_child(struct sock *sk, 414 struct request_sock *req, 415 struct sk_buff *skb); 416 417 extern struct sock * tcp_v4_syn_recv_sock(struct sock *sk, 418 struct sk_buff *skb, 419 struct request_sock *req, 420 struct dst_entry *dst); 421 422 extern int tcp_v4_do_rcv(struct sock *sk, 423 struct sk_buff *skb); 424 425 extern int tcp_v4_connect(struct sock *sk, 426 struct sockaddr *uaddr, 427 int addr_len); 428 429 extern int tcp_connect(struct sock *sk); 430 431 extern struct sk_buff * tcp_make_synack(struct sock *sk, 432 struct dst_entry *dst, 433 struct request_sock *req); 434 435 extern int tcp_disconnect(struct sock *sk, int flags); 436 437 extern void tcp_unhash(struct sock *sk); 438 439 extern int tcp_v4_hash_connecting(struct sock *sk); 440 441 442 /* From syncookies.c */ 443 extern struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb, 444 struct ip_options *opt); 445 extern __u32 cookie_v4_init_sequence(struct sock *sk, struct sk_buff *skb, 446 __u16 *mss); 447 448 /* tcp_output.c */ 449 450 extern void __tcp_push_pending_frames(struct sock *sk, struct tcp_sock *tp, 451 unsigned int cur_mss, int nonagle); 452 extern int tcp_may_send_now(struct sock *sk, struct tcp_sock *tp); 453 extern int tcp_retransmit_skb(struct sock *, struct sk_buff *); 454 extern void tcp_xmit_retransmit_queue(struct sock *); 455 extern void tcp_simple_retransmit(struct sock *); 456 extern int tcp_trim_head(struct sock *, struct sk_buff *, u32); 457 extern int tcp_fragment(struct sock *, struct sk_buff *, u32, unsigned int); 458 459 extern void tcp_send_probe0(struct sock *); 460 extern void tcp_send_partial(struct sock *); 461 extern int tcp_write_wakeup(struct sock *); 462 extern void tcp_send_fin(struct sock *sk); 463 extern void tcp_send_active_reset(struct sock *sk, gfp_t priority); 464 extern int tcp_send_synack(struct sock *); 465 extern void tcp_push_one(struct sock *, unsigned int mss_now); 466 extern void tcp_send_ack(struct sock *sk); 467 extern void tcp_send_delayed_ack(struct sock *sk); 468 469 /* tcp_input.c */ 470 extern void tcp_cwnd_application_limited(struct sock *sk); 471 472 /* tcp_timer.c */ 473 extern void tcp_init_xmit_timers(struct sock *); 474 static inline void tcp_clear_xmit_timers(struct sock *sk) 475 { 476 inet_csk_clear_xmit_timers(sk); 477 } 478 479 extern unsigned int tcp_sync_mss(struct sock *sk, u32 pmtu); 480 extern unsigned int tcp_current_mss(struct sock *sk, int large); 481 482 /* tcp.c */ 483 extern void tcp_get_info(struct sock *, struct tcp_info *); 484 485 /* Read 'sendfile()'-style from a TCP socket */ 486 typedef int (*sk_read_actor_t)(read_descriptor_t *, struct sk_buff *, 487 unsigned int, size_t); 488 extern int tcp_read_sock(struct sock *sk, read_descriptor_t *desc, 489 sk_read_actor_t recv_actor); 490 491 /* Initialize RCV_MSS value. 492 * RCV_MSS is an our guess about MSS used by the peer. 493 * We haven't any direct information about the MSS. 494 * It's better to underestimate the RCV_MSS rather than overestimate. 495 * Overestimations make us ACKing less frequently than needed. 496 * Underestimations are more easy to detect and fix by tcp_measure_rcv_mss(). 497 */ 498 499 static inline void tcp_initialize_rcv_mss(struct sock *sk) 500 { 501 struct tcp_sock *tp = tcp_sk(sk); 502 unsigned int hint = min_t(unsigned int, tp->advmss, tp->mss_cache); 503 504 hint = min(hint, tp->rcv_wnd/2); 505 hint = min(hint, TCP_MIN_RCVMSS); 506 hint = max(hint, TCP_MIN_MSS); 507 508 inet_csk(sk)->icsk_ack.rcv_mss = hint; 509 } 510 511 static __inline__ void __tcp_fast_path_on(struct tcp_sock *tp, u32 snd_wnd) 512 { 513 tp->pred_flags = htonl((tp->tcp_header_len << 26) | 514 ntohl(TCP_FLAG_ACK) | 515 snd_wnd); 516 } 517 518 static __inline__ void tcp_fast_path_on(struct tcp_sock *tp) 519 { 520 __tcp_fast_path_on(tp, tp->snd_wnd >> tp->rx_opt.snd_wscale); 521 } 522 523 static inline void tcp_fast_path_check(struct sock *sk, struct tcp_sock *tp) 524 { 525 if (skb_queue_empty(&tp->out_of_order_queue) && 526 tp->rcv_wnd && 527 atomic_read(&sk->sk_rmem_alloc) < sk->sk_rcvbuf && 528 !tp->urg_data) 529 tcp_fast_path_on(tp); 530 } 531 532 /* Compute the actual receive window we are currently advertising. 533 * Rcv_nxt can be after the window if our peer push more data 534 * than the offered window. 535 */ 536 static __inline__ u32 tcp_receive_window(const struct tcp_sock *tp) 537 { 538 s32 win = tp->rcv_wup + tp->rcv_wnd - tp->rcv_nxt; 539 540 if (win < 0) 541 win = 0; 542 return (u32) win; 543 } 544 545 /* Choose a new window, without checks for shrinking, and without 546 * scaling applied to the result. The caller does these things 547 * if necessary. This is a "raw" window selection. 548 */ 549 extern u32 __tcp_select_window(struct sock *sk); 550 551 /* TCP timestamps are only 32-bits, this causes a slight 552 * complication on 64-bit systems since we store a snapshot 553 * of jiffies in the buffer control blocks below. We decidely 554 * only use of the low 32-bits of jiffies and hide the ugly 555 * casts with the following macro. 556 */ 557 #define tcp_time_stamp ((__u32)(jiffies)) 558 559 /* This is what the send packet queueing engine uses to pass 560 * TCP per-packet control information to the transmission 561 * code. We also store the host-order sequence numbers in 562 * here too. This is 36 bytes on 32-bit architectures, 563 * 40 bytes on 64-bit machines, if this grows please adjust 564 * skbuff.h:skbuff->cb[xxx] size appropriately. 565 */ 566 struct tcp_skb_cb { 567 union { 568 struct inet_skb_parm h4; 569 #if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE) 570 struct inet6_skb_parm h6; 571 #endif 572 } header; /* For incoming frames */ 573 __u32 seq; /* Starting sequence number */ 574 __u32 end_seq; /* SEQ + FIN + SYN + datalen */ 575 __u32 when; /* used to compute rtt's */ 576 __u8 flags; /* TCP header flags. */ 577 578 /* NOTE: These must match up to the flags byte in a 579 * real TCP header. 580 */ 581 #define TCPCB_FLAG_FIN 0x01 582 #define TCPCB_FLAG_SYN 0x02 583 #define TCPCB_FLAG_RST 0x04 584 #define TCPCB_FLAG_PSH 0x08 585 #define TCPCB_FLAG_ACK 0x10 586 #define TCPCB_FLAG_URG 0x20 587 #define TCPCB_FLAG_ECE 0x40 588 #define TCPCB_FLAG_CWR 0x80 589 590 __u8 sacked; /* State flags for SACK/FACK. */ 591 #define TCPCB_SACKED_ACKED 0x01 /* SKB ACK'd by a SACK block */ 592 #define TCPCB_SACKED_RETRANS 0x02 /* SKB retransmitted */ 593 #define TCPCB_LOST 0x04 /* SKB is lost */ 594 #define TCPCB_TAGBITS 0x07 /* All tag bits */ 595 596 #define TCPCB_EVER_RETRANS 0x80 /* Ever retransmitted frame */ 597 #define TCPCB_RETRANS (TCPCB_SACKED_RETRANS|TCPCB_EVER_RETRANS) 598 599 #define TCPCB_URG 0x20 /* Urgent pointer advenced here */ 600 601 #define TCPCB_AT_TAIL (TCPCB_URG) 602 603 __u16 urg_ptr; /* Valid w/URG flags is set. */ 604 __u32 ack_seq; /* Sequence number ACK'd */ 605 }; 606 607 #define TCP_SKB_CB(__skb) ((struct tcp_skb_cb *)&((__skb)->cb[0])) 608 609 #include <net/tcp_ecn.h> 610 611 /* Due to TSO, an SKB can be composed of multiple actual 612 * packets. To keep these tracked properly, we use this. 613 */ 614 static inline int tcp_skb_pcount(const struct sk_buff *skb) 615 { 616 return skb_shinfo(skb)->tso_segs; 617 } 618 619 /* This is valid iff tcp_skb_pcount() > 1. */ 620 static inline int tcp_skb_mss(const struct sk_buff *skb) 621 { 622 return skb_shinfo(skb)->tso_size; 623 } 624 625 static inline void tcp_dec_pcount_approx(__u32 *count, 626 const struct sk_buff *skb) 627 { 628 if (*count) { 629 *count -= tcp_skb_pcount(skb); 630 if ((int)*count < 0) 631 *count = 0; 632 } 633 } 634 635 static inline void tcp_packets_out_inc(struct sock *sk, 636 struct tcp_sock *tp, 637 const struct sk_buff *skb) 638 { 639 int orig = tp->packets_out; 640 641 tp->packets_out += tcp_skb_pcount(skb); 642 if (!orig) 643 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, 644 inet_csk(sk)->icsk_rto, TCP_RTO_MAX); 645 } 646 647 static inline void tcp_packets_out_dec(struct tcp_sock *tp, 648 const struct sk_buff *skb) 649 { 650 tp->packets_out -= tcp_skb_pcount(skb); 651 } 652 653 /* Events passed to congestion control interface */ 654 enum tcp_ca_event { 655 CA_EVENT_TX_START, /* first transmit when no packets in flight */ 656 CA_EVENT_CWND_RESTART, /* congestion window restart */ 657 CA_EVENT_COMPLETE_CWR, /* end of congestion recovery */ 658 CA_EVENT_FRTO, /* fast recovery timeout */ 659 CA_EVENT_LOSS, /* loss timeout */ 660 CA_EVENT_FAST_ACK, /* in sequence ack */ 661 CA_EVENT_SLOW_ACK, /* other ack */ 662 }; 663 664 /* 665 * Interface for adding new TCP congestion control handlers 666 */ 667 #define TCP_CA_NAME_MAX 16 668 struct tcp_congestion_ops { 669 struct list_head list; 670 671 /* initialize private data (optional) */ 672 void (*init)(struct sock *sk); 673 /* cleanup private data (optional) */ 674 void (*release)(struct sock *sk); 675 676 /* return slow start threshold (required) */ 677 u32 (*ssthresh)(struct sock *sk); 678 /* lower bound for congestion window (optional) */ 679 u32 (*min_cwnd)(struct sock *sk); 680 /* do new cwnd calculation (required) */ 681 void (*cong_avoid)(struct sock *sk, u32 ack, 682 u32 rtt, u32 in_flight, int good_ack); 683 /* round trip time sample per acked packet (optional) */ 684 void (*rtt_sample)(struct sock *sk, u32 usrtt); 685 /* call before changing ca_state (optional) */ 686 void (*set_state)(struct sock *sk, u8 new_state); 687 /* call when cwnd event occurs (optional) */ 688 void (*cwnd_event)(struct sock *sk, enum tcp_ca_event ev); 689 /* new value of cwnd after loss (optional) */ 690 u32 (*undo_cwnd)(struct sock *sk); 691 /* hook for packet ack accounting (optional) */ 692 void (*pkts_acked)(struct sock *sk, u32 num_acked); 693 /* get info for inet_diag (optional) */ 694 void (*get_info)(struct sock *sk, u32 ext, struct sk_buff *skb); 695 696 char name[TCP_CA_NAME_MAX]; 697 struct module *owner; 698 }; 699 700 extern int tcp_register_congestion_control(struct tcp_congestion_ops *type); 701 extern void tcp_unregister_congestion_control(struct tcp_congestion_ops *type); 702 703 extern void tcp_init_congestion_control(struct sock *sk); 704 extern void tcp_cleanup_congestion_control(struct sock *sk); 705 extern int tcp_set_default_congestion_control(const char *name); 706 extern void tcp_get_default_congestion_control(char *name); 707 extern int tcp_set_congestion_control(struct sock *sk, const char *name); 708 709 extern struct tcp_congestion_ops tcp_init_congestion_ops; 710 extern u32 tcp_reno_ssthresh(struct sock *sk); 711 extern void tcp_reno_cong_avoid(struct sock *sk, u32 ack, 712 u32 rtt, u32 in_flight, int flag); 713 extern u32 tcp_reno_min_cwnd(struct sock *sk); 714 extern struct tcp_congestion_ops tcp_reno; 715 716 static inline void tcp_set_ca_state(struct sock *sk, const u8 ca_state) 717 { 718 struct inet_connection_sock *icsk = inet_csk(sk); 719 720 if (icsk->icsk_ca_ops->set_state) 721 icsk->icsk_ca_ops->set_state(sk, ca_state); 722 icsk->icsk_ca_state = ca_state; 723 } 724 725 static inline void tcp_ca_event(struct sock *sk, const enum tcp_ca_event event) 726 { 727 const struct inet_connection_sock *icsk = inet_csk(sk); 728 729 if (icsk->icsk_ca_ops->cwnd_event) 730 icsk->icsk_ca_ops->cwnd_event(sk, event); 731 } 732 733 /* This determines how many packets are "in the network" to the best 734 * of our knowledge. In many cases it is conservative, but where 735 * detailed information is available from the receiver (via SACK 736 * blocks etc.) we can make more aggressive calculations. 737 * 738 * Use this for decisions involving congestion control, use just 739 * tp->packets_out to determine if the send queue is empty or not. 740 * 741 * Read this equation as: 742 * 743 * "Packets sent once on transmission queue" MINUS 744 * "Packets left network, but not honestly ACKed yet" PLUS 745 * "Packets fast retransmitted" 746 */ 747 static __inline__ unsigned int tcp_packets_in_flight(const struct tcp_sock *tp) 748 { 749 return (tp->packets_out - tp->left_out + tp->retrans_out); 750 } 751 752 /* If cwnd > ssthresh, we may raise ssthresh to be half-way to cwnd. 753 * The exception is rate halving phase, when cwnd is decreasing towards 754 * ssthresh. 755 */ 756 static inline __u32 tcp_current_ssthresh(const struct sock *sk) 757 { 758 const struct tcp_sock *tp = tcp_sk(sk); 759 if ((1 << inet_csk(sk)->icsk_ca_state) & (TCPF_CA_CWR | TCPF_CA_Recovery)) 760 return tp->snd_ssthresh; 761 else 762 return max(tp->snd_ssthresh, 763 ((tp->snd_cwnd >> 1) + 764 (tp->snd_cwnd >> 2))); 765 } 766 767 static inline void tcp_sync_left_out(struct tcp_sock *tp) 768 { 769 if (tp->rx_opt.sack_ok && 770 (tp->sacked_out >= tp->packets_out - tp->lost_out)) 771 tp->sacked_out = tp->packets_out - tp->lost_out; 772 tp->left_out = tp->sacked_out + tp->lost_out; 773 } 774 775 /* Set slow start threshold and cwnd not falling to slow start */ 776 static inline void __tcp_enter_cwr(struct sock *sk) 777 { 778 const struct inet_connection_sock *icsk = inet_csk(sk); 779 struct tcp_sock *tp = tcp_sk(sk); 780 781 tp->undo_marker = 0; 782 tp->snd_ssthresh = icsk->icsk_ca_ops->ssthresh(sk); 783 tp->snd_cwnd = min(tp->snd_cwnd, 784 tcp_packets_in_flight(tp) + 1U); 785 tp->snd_cwnd_cnt = 0; 786 tp->high_seq = tp->snd_nxt; 787 tp->snd_cwnd_stamp = tcp_time_stamp; 788 TCP_ECN_queue_cwr(tp); 789 } 790 791 static inline void tcp_enter_cwr(struct sock *sk) 792 { 793 struct tcp_sock *tp = tcp_sk(sk); 794 795 tp->prior_ssthresh = 0; 796 if (inet_csk(sk)->icsk_ca_state < TCP_CA_CWR) { 797 __tcp_enter_cwr(sk); 798 tcp_set_ca_state(sk, TCP_CA_CWR); 799 } 800 } 801 802 extern __u32 tcp_init_cwnd(struct tcp_sock *tp, struct dst_entry *dst); 803 804 /* Slow start with delack produces 3 packets of burst, so that 805 * it is safe "de facto". 806 */ 807 static __inline__ __u32 tcp_max_burst(const struct tcp_sock *tp) 808 { 809 return 3; 810 } 811 812 static __inline__ void tcp_minshall_update(struct tcp_sock *tp, int mss, 813 const struct sk_buff *skb) 814 { 815 if (skb->len < mss) 816 tp->snd_sml = TCP_SKB_CB(skb)->end_seq; 817 } 818 819 static __inline__ void tcp_check_probe_timer(struct sock *sk, struct tcp_sock *tp) 820 { 821 const struct inet_connection_sock *icsk = inet_csk(sk); 822 if (!tp->packets_out && !icsk->icsk_pending) 823 inet_csk_reset_xmit_timer(sk, ICSK_TIME_PROBE0, 824 icsk->icsk_rto, TCP_RTO_MAX); 825 } 826 827 static __inline__ void tcp_push_pending_frames(struct sock *sk, 828 struct tcp_sock *tp) 829 { 830 __tcp_push_pending_frames(sk, tp, tcp_current_mss(sk, 1), tp->nonagle); 831 } 832 833 static __inline__ void tcp_init_wl(struct tcp_sock *tp, u32 ack, u32 seq) 834 { 835 tp->snd_wl1 = seq; 836 } 837 838 static __inline__ void tcp_update_wl(struct tcp_sock *tp, u32 ack, u32 seq) 839 { 840 tp->snd_wl1 = seq; 841 } 842 843 /* 844 * Calculate(/check) TCP checksum 845 */ 846 static __inline__ u16 tcp_v4_check(struct tcphdr *th, int len, 847 unsigned long saddr, unsigned long daddr, 848 unsigned long base) 849 { 850 return csum_tcpudp_magic(saddr,daddr,len,IPPROTO_TCP,base); 851 } 852 853 static __inline__ int __tcp_checksum_complete(struct sk_buff *skb) 854 { 855 return (unsigned short)csum_fold(skb_checksum(skb, 0, skb->len, skb->csum)); 856 } 857 858 static __inline__ int tcp_checksum_complete(struct sk_buff *skb) 859 { 860 return skb->ip_summed != CHECKSUM_UNNECESSARY && 861 __tcp_checksum_complete(skb); 862 } 863 864 /* Prequeue for VJ style copy to user, combined with checksumming. */ 865 866 static __inline__ void tcp_prequeue_init(struct tcp_sock *tp) 867 { 868 tp->ucopy.task = NULL; 869 tp->ucopy.len = 0; 870 tp->ucopy.memory = 0; 871 skb_queue_head_init(&tp->ucopy.prequeue); 872 } 873 874 /* Packet is added to VJ-style prequeue for processing in process 875 * context, if a reader task is waiting. Apparently, this exciting 876 * idea (VJ's mail "Re: query about TCP header on tcp-ip" of 07 Sep 93) 877 * failed somewhere. Latency? Burstiness? Well, at least now we will 878 * see, why it failed. 8)8) --ANK 879 * 880 * NOTE: is this not too big to inline? 881 */ 882 static __inline__ int tcp_prequeue(struct sock *sk, struct sk_buff *skb) 883 { 884 struct tcp_sock *tp = tcp_sk(sk); 885 886 if (!sysctl_tcp_low_latency && tp->ucopy.task) { 887 __skb_queue_tail(&tp->ucopy.prequeue, skb); 888 tp->ucopy.memory += skb->truesize; 889 if (tp->ucopy.memory > sk->sk_rcvbuf) { 890 struct sk_buff *skb1; 891 892 BUG_ON(sock_owned_by_user(sk)); 893 894 while ((skb1 = __skb_dequeue(&tp->ucopy.prequeue)) != NULL) { 895 sk->sk_backlog_rcv(sk, skb1); 896 NET_INC_STATS_BH(LINUX_MIB_TCPPREQUEUEDROPPED); 897 } 898 899 tp->ucopy.memory = 0; 900 } else if (skb_queue_len(&tp->ucopy.prequeue) == 1) { 901 wake_up_interruptible(sk->sk_sleep); 902 if (!inet_csk_ack_scheduled(sk)) 903 inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK, 904 (3 * TCP_RTO_MIN) / 4, 905 TCP_RTO_MAX); 906 } 907 return 1; 908 } 909 return 0; 910 } 911 912 913 #undef STATE_TRACE 914 915 #ifdef STATE_TRACE 916 static const char *statename[]={ 917 "Unused","Established","Syn Sent","Syn Recv", 918 "Fin Wait 1","Fin Wait 2","Time Wait", "Close", 919 "Close Wait","Last ACK","Listen","Closing" 920 }; 921 #endif 922 923 static __inline__ void tcp_set_state(struct sock *sk, int state) 924 { 925 int oldstate = sk->sk_state; 926 927 switch (state) { 928 case TCP_ESTABLISHED: 929 if (oldstate != TCP_ESTABLISHED) 930 TCP_INC_STATS(TCP_MIB_CURRESTAB); 931 break; 932 933 case TCP_CLOSE: 934 if (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED) 935 TCP_INC_STATS(TCP_MIB_ESTABRESETS); 936 937 sk->sk_prot->unhash(sk); 938 if (inet_csk(sk)->icsk_bind_hash && 939 !(sk->sk_userlocks & SOCK_BINDPORT_LOCK)) 940 inet_put_port(&tcp_hashinfo, sk); 941 /* fall through */ 942 default: 943 if (oldstate==TCP_ESTABLISHED) 944 TCP_DEC_STATS(TCP_MIB_CURRESTAB); 945 } 946 947 /* Change state AFTER socket is unhashed to avoid closed 948 * socket sitting in hash tables. 949 */ 950 sk->sk_state = state; 951 952 #ifdef STATE_TRACE 953 SOCK_DEBUG(sk, "TCP sk=%p, State %s -> %s\n",sk, statename[oldstate],statename[state]); 954 #endif 955 } 956 957 static __inline__ void tcp_done(struct sock *sk) 958 { 959 tcp_set_state(sk, TCP_CLOSE); 960 tcp_clear_xmit_timers(sk); 961 962 sk->sk_shutdown = SHUTDOWN_MASK; 963 964 if (!sock_flag(sk, SOCK_DEAD)) 965 sk->sk_state_change(sk); 966 else 967 inet_csk_destroy_sock(sk); 968 } 969 970 static __inline__ void tcp_sack_reset(struct tcp_options_received *rx_opt) 971 { 972 rx_opt->dsack = 0; 973 rx_opt->eff_sacks = 0; 974 rx_opt->num_sacks = 0; 975 } 976 977 static __inline__ void tcp_build_and_update_options(__u32 *ptr, struct tcp_sock *tp, __u32 tstamp) 978 { 979 if (tp->rx_opt.tstamp_ok) { 980 *ptr++ = __constant_htonl((TCPOPT_NOP << 24) | 981 (TCPOPT_NOP << 16) | 982 (TCPOPT_TIMESTAMP << 8) | 983 TCPOLEN_TIMESTAMP); 984 *ptr++ = htonl(tstamp); 985 *ptr++ = htonl(tp->rx_opt.ts_recent); 986 } 987 if (tp->rx_opt.eff_sacks) { 988 struct tcp_sack_block *sp = tp->rx_opt.dsack ? tp->duplicate_sack : tp->selective_acks; 989 int this_sack; 990 991 *ptr++ = __constant_htonl((TCPOPT_NOP << 24) | 992 (TCPOPT_NOP << 16) | 993 (TCPOPT_SACK << 8) | 994 (TCPOLEN_SACK_BASE + 995 (tp->rx_opt.eff_sacks * TCPOLEN_SACK_PERBLOCK))); 996 for(this_sack = 0; this_sack < tp->rx_opt.eff_sacks; this_sack++) { 997 *ptr++ = htonl(sp[this_sack].start_seq); 998 *ptr++ = htonl(sp[this_sack].end_seq); 999 } 1000 if (tp->rx_opt.dsack) { 1001 tp->rx_opt.dsack = 0; 1002 tp->rx_opt.eff_sacks--; 1003 } 1004 } 1005 } 1006 1007 /* Construct a tcp options header for a SYN or SYN_ACK packet. 1008 * If this is every changed make sure to change the definition of 1009 * MAX_SYN_SIZE to match the new maximum number of options that you 1010 * can generate. 1011 */ 1012 static inline void tcp_syn_build_options(__u32 *ptr, int mss, int ts, int sack, 1013 int offer_wscale, int wscale, __u32 tstamp, __u32 ts_recent) 1014 { 1015 /* We always get an MSS option. 1016 * The option bytes which will be seen in normal data 1017 * packets should timestamps be used, must be in the MSS 1018 * advertised. But we subtract them from tp->mss_cache so 1019 * that calculations in tcp_sendmsg are simpler etc. 1020 * So account for this fact here if necessary. If we 1021 * don't do this correctly, as a receiver we won't 1022 * recognize data packets as being full sized when we 1023 * should, and thus we won't abide by the delayed ACK 1024 * rules correctly. 1025 * SACKs don't matter, we never delay an ACK when we 1026 * have any of those going out. 1027 */ 1028 *ptr++ = htonl((TCPOPT_MSS << 24) | (TCPOLEN_MSS << 16) | mss); 1029 if (ts) { 1030 if(sack) 1031 *ptr++ = __constant_htonl((TCPOPT_SACK_PERM << 24) | (TCPOLEN_SACK_PERM << 16) | 1032 (TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP); 1033 else 1034 *ptr++ = __constant_htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) | 1035 (TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP); 1036 *ptr++ = htonl(tstamp); /* TSVAL */ 1037 *ptr++ = htonl(ts_recent); /* TSECR */ 1038 } else if(sack) 1039 *ptr++ = __constant_htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) | 1040 (TCPOPT_SACK_PERM << 8) | TCPOLEN_SACK_PERM); 1041 if (offer_wscale) 1042 *ptr++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_WINDOW << 16) | (TCPOLEN_WINDOW << 8) | (wscale)); 1043 } 1044 1045 /* Determine a window scaling and initial window to offer. */ 1046 extern void tcp_select_initial_window(int __space, __u32 mss, 1047 __u32 *rcv_wnd, __u32 *window_clamp, 1048 int wscale_ok, __u8 *rcv_wscale); 1049 1050 static inline int tcp_win_from_space(int space) 1051 { 1052 return sysctl_tcp_adv_win_scale<=0 ? 1053 (space>>(-sysctl_tcp_adv_win_scale)) : 1054 space - (space>>sysctl_tcp_adv_win_scale); 1055 } 1056 1057 /* Note: caller must be prepared to deal with negative returns */ 1058 static inline int tcp_space(const struct sock *sk) 1059 { 1060 return tcp_win_from_space(sk->sk_rcvbuf - 1061 atomic_read(&sk->sk_rmem_alloc)); 1062 } 1063 1064 static inline int tcp_full_space(const struct sock *sk) 1065 { 1066 return tcp_win_from_space(sk->sk_rcvbuf); 1067 } 1068 1069 static __inline__ void tcp_openreq_init(struct request_sock *req, 1070 struct tcp_options_received *rx_opt, 1071 struct sk_buff *skb) 1072 { 1073 struct inet_request_sock *ireq = inet_rsk(req); 1074 1075 req->rcv_wnd = 0; /* So that tcp_send_synack() knows! */ 1076 tcp_rsk(req)->rcv_isn = TCP_SKB_CB(skb)->seq; 1077 req->mss = rx_opt->mss_clamp; 1078 req->ts_recent = rx_opt->saw_tstamp ? rx_opt->rcv_tsval : 0; 1079 ireq->tstamp_ok = rx_opt->tstamp_ok; 1080 ireq->sack_ok = rx_opt->sack_ok; 1081 ireq->snd_wscale = rx_opt->snd_wscale; 1082 ireq->wscale_ok = rx_opt->wscale_ok; 1083 ireq->acked = 0; 1084 ireq->ecn_ok = 0; 1085 ireq->rmt_port = skb->h.th->source; 1086 } 1087 1088 extern void tcp_enter_memory_pressure(void); 1089 1090 static inline int keepalive_intvl_when(const struct tcp_sock *tp) 1091 { 1092 return tp->keepalive_intvl ? : sysctl_tcp_keepalive_intvl; 1093 } 1094 1095 static inline int keepalive_time_when(const struct tcp_sock *tp) 1096 { 1097 return tp->keepalive_time ? : sysctl_tcp_keepalive_time; 1098 } 1099 1100 static inline int tcp_fin_time(const struct sock *sk) 1101 { 1102 int fin_timeout = tcp_sk(sk)->linger2 ? : sysctl_tcp_fin_timeout; 1103 const int rto = inet_csk(sk)->icsk_rto; 1104 1105 if (fin_timeout < (rto << 2) - (rto >> 1)) 1106 fin_timeout = (rto << 2) - (rto >> 1); 1107 1108 return fin_timeout; 1109 } 1110 1111 static inline int tcp_paws_check(const struct tcp_options_received *rx_opt, int rst) 1112 { 1113 if ((s32)(rx_opt->rcv_tsval - rx_opt->ts_recent) >= 0) 1114 return 0; 1115 if (xtime.tv_sec >= rx_opt->ts_recent_stamp + TCP_PAWS_24DAYS) 1116 return 0; 1117 1118 /* RST segments are not recommended to carry timestamp, 1119 and, if they do, it is recommended to ignore PAWS because 1120 "their cleanup function should take precedence over timestamps." 1121 Certainly, it is mistake. It is necessary to understand the reasons 1122 of this constraint to relax it: if peer reboots, clock may go 1123 out-of-sync and half-open connections will not be reset. 1124 Actually, the problem would be not existing if all 1125 the implementations followed draft about maintaining clock 1126 via reboots. Linux-2.2 DOES NOT! 1127 1128 However, we can relax time bounds for RST segments to MSL. 1129 */ 1130 if (rst && xtime.tv_sec >= rx_opt->ts_recent_stamp + TCP_PAWS_MSL) 1131 return 0; 1132 return 1; 1133 } 1134 1135 #define TCP_CHECK_TIMER(sk) do { } while (0) 1136 1137 static inline int tcp_use_frto(const struct sock *sk) 1138 { 1139 const struct tcp_sock *tp = tcp_sk(sk); 1140 1141 /* F-RTO must be activated in sysctl and there must be some 1142 * unsent new data, and the advertised window should allow 1143 * sending it. 1144 */ 1145 return (sysctl_tcp_frto && sk->sk_send_head && 1146 !after(TCP_SKB_CB(sk->sk_send_head)->end_seq, 1147 tp->snd_una + tp->snd_wnd)); 1148 } 1149 1150 static inline void tcp_mib_init(void) 1151 { 1152 /* See RFC 2012 */ 1153 TCP_ADD_STATS_USER(TCP_MIB_RTOALGORITHM, 1); 1154 TCP_ADD_STATS_USER(TCP_MIB_RTOMIN, TCP_RTO_MIN*1000/HZ); 1155 TCP_ADD_STATS_USER(TCP_MIB_RTOMAX, TCP_RTO_MAX*1000/HZ); 1156 TCP_ADD_STATS_USER(TCP_MIB_MAXCONN, -1); 1157 } 1158 1159 /* /proc */ 1160 enum tcp_seq_states { 1161 TCP_SEQ_STATE_LISTENING, 1162 TCP_SEQ_STATE_OPENREQ, 1163 TCP_SEQ_STATE_ESTABLISHED, 1164 TCP_SEQ_STATE_TIME_WAIT, 1165 }; 1166 1167 struct tcp_seq_afinfo { 1168 struct module *owner; 1169 char *name; 1170 sa_family_t family; 1171 int (*seq_show) (struct seq_file *m, void *v); 1172 struct file_operations *seq_fops; 1173 }; 1174 1175 struct tcp_iter_state { 1176 sa_family_t family; 1177 enum tcp_seq_states state; 1178 struct sock *syn_wait_sk; 1179 int bucket, sbucket, num, uid; 1180 struct seq_operations seq_ops; 1181 }; 1182 1183 extern int tcp_proc_register(struct tcp_seq_afinfo *afinfo); 1184 extern void tcp_proc_unregister(struct tcp_seq_afinfo *afinfo); 1185 1186 extern struct request_sock_ops tcp_request_sock_ops; 1187 1188 extern int tcp_v4_destroy_sock(struct sock *sk); 1189 1190 #ifdef CONFIG_PROC_FS 1191 extern int tcp4_proc_init(void); 1192 extern void tcp4_proc_exit(void); 1193 #endif 1194 1195 extern void tcp_v4_init(struct net_proto_family *ops); 1196 extern void tcp_init(void); 1197 1198 #endif /* _TCP_H */ 1199