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/list.h> 25 #include <linux/tcp.h> 26 #include <linux/slab.h> 27 #include <linux/cache.h> 28 #include <linux/percpu.h> 29 #include <linux/skbuff.h> 30 #include <linux/dmaengine.h> 31 #include <linux/crypto.h> 32 33 #include <net/inet_connection_sock.h> 34 #include <net/inet_timewait_sock.h> 35 #include <net/inet_hashtables.h> 36 #include <net/checksum.h> 37 #include <net/request_sock.h> 38 #include <net/sock.h> 39 #include <net/snmp.h> 40 #include <net/ip.h> 41 #include <net/tcp_states.h> 42 43 #include <linux/seq_file.h> 44 45 extern struct inet_hashinfo tcp_hashinfo; 46 47 extern atomic_t tcp_orphan_count; 48 extern void tcp_time_wait(struct sock *sk, int state, int timeo); 49 50 #define MAX_TCP_HEADER (128 + MAX_HEADER) 51 52 /* 53 * Never offer a window over 32767 without using window scaling. Some 54 * poor stacks do signed 16bit maths! 55 */ 56 #define MAX_TCP_WINDOW 32767U 57 58 /* Minimal accepted MSS. It is (60+60+8) - (20+20). */ 59 #define TCP_MIN_MSS 88U 60 61 /* Minimal RCV_MSS. */ 62 #define TCP_MIN_RCVMSS 536U 63 64 /* The least MTU to use for probing */ 65 #define TCP_BASE_MSS 512 66 67 /* After receiving this amount of duplicate ACKs fast retransmit starts. */ 68 #define TCP_FASTRETRANS_THRESH 3 69 70 /* Maximal reordering. */ 71 #define TCP_MAX_REORDERING 127 72 73 /* Maximal number of ACKs sent quickly to accelerate slow-start. */ 74 #define TCP_MAX_QUICKACKS 16U 75 76 /* urg_data states */ 77 #define TCP_URG_VALID 0x0100 78 #define TCP_URG_NOTYET 0x0200 79 #define TCP_URG_READ 0x0400 80 81 #define TCP_RETR1 3 /* 82 * This is how many retries it does before it 83 * tries to figure out if the gateway is 84 * down. Minimal RFC value is 3; it corresponds 85 * to ~3sec-8min depending on RTO. 86 */ 87 88 #define TCP_RETR2 15 /* 89 * This should take at least 90 * 90 minutes to time out. 91 * RFC1122 says that the limit is 100 sec. 92 * 15 is ~13-30min depending on RTO. 93 */ 94 95 #define TCP_SYN_RETRIES 5 /* number of times to retry active opening a 96 * connection: ~180sec is RFC minimum */ 97 98 #define TCP_SYNACK_RETRIES 5 /* number of times to retry passive opening a 99 * connection: ~180sec is RFC minimum */ 100 101 102 #define TCP_ORPHAN_RETRIES 7 /* number of times to retry on an orphaned 103 * socket. 7 is ~50sec-16min. 104 */ 105 106 107 #define TCP_TIMEWAIT_LEN (60*HZ) /* how long to wait to destroy TIME-WAIT 108 * state, about 60 seconds */ 109 #define TCP_FIN_TIMEOUT TCP_TIMEWAIT_LEN 110 /* BSD style FIN_WAIT2 deadlock breaker. 111 * It used to be 3min, new value is 60sec, 112 * to combine FIN-WAIT-2 timeout with 113 * TIME-WAIT timer. 114 */ 115 116 #define TCP_DELACK_MAX ((unsigned)(HZ/5)) /* maximal time to delay before sending an ACK */ 117 #if HZ >= 100 118 #define TCP_DELACK_MIN ((unsigned)(HZ/25)) /* minimal time to delay before sending an ACK */ 119 #define TCP_ATO_MIN ((unsigned)(HZ/25)) 120 #else 121 #define TCP_DELACK_MIN 4U 122 #define TCP_ATO_MIN 4U 123 #endif 124 #define TCP_RTO_MAX ((unsigned)(120*HZ)) 125 #define TCP_RTO_MIN ((unsigned)(HZ/5)) 126 #define TCP_TIMEOUT_INIT ((unsigned)(3*HZ)) /* RFC 1122 initial RTO value */ 127 128 #define TCP_RESOURCE_PROBE_INTERVAL ((unsigned)(HZ/2U)) /* Maximal interval between probes 129 * for local resources. 130 */ 131 132 #define TCP_KEEPALIVE_TIME (120*60*HZ) /* two hours */ 133 #define TCP_KEEPALIVE_PROBES 9 /* Max of 9 keepalive probes */ 134 #define TCP_KEEPALIVE_INTVL (75*HZ) 135 136 #define MAX_TCP_KEEPIDLE 32767 137 #define MAX_TCP_KEEPINTVL 32767 138 #define MAX_TCP_KEEPCNT 127 139 #define MAX_TCP_SYNCNT 127 140 141 #define TCP_SYNQ_INTERVAL (HZ/5) /* Period of SYNACK timer */ 142 143 #define TCP_PAWS_24DAYS (60 * 60 * 24 * 24) 144 #define TCP_PAWS_MSL 60 /* Per-host timestamps are invalidated 145 * after this time. It should be equal 146 * (or greater than) TCP_TIMEWAIT_LEN 147 * to provide reliability equal to one 148 * provided by timewait state. 149 */ 150 #define TCP_PAWS_WINDOW 1 /* Replay window for per-host 151 * timestamps. It must be less than 152 * minimal timewait lifetime. 153 */ 154 /* 155 * TCP option 156 */ 157 158 #define TCPOPT_NOP 1 /* Padding */ 159 #define TCPOPT_EOL 0 /* End of options */ 160 #define TCPOPT_MSS 2 /* Segment size negotiating */ 161 #define TCPOPT_WINDOW 3 /* Window scaling */ 162 #define TCPOPT_SACK_PERM 4 /* SACK Permitted */ 163 #define TCPOPT_SACK 5 /* SACK Block */ 164 #define TCPOPT_TIMESTAMP 8 /* Better RTT estimations/PAWS */ 165 #define TCPOPT_MD5SIG 19 /* MD5 Signature (RFC2385) */ 166 167 /* 168 * TCP option lengths 169 */ 170 171 #define TCPOLEN_MSS 4 172 #define TCPOLEN_WINDOW 3 173 #define TCPOLEN_SACK_PERM 2 174 #define TCPOLEN_TIMESTAMP 10 175 #define TCPOLEN_MD5SIG 18 176 177 /* But this is what stacks really send out. */ 178 #define TCPOLEN_TSTAMP_ALIGNED 12 179 #define TCPOLEN_WSCALE_ALIGNED 4 180 #define TCPOLEN_SACKPERM_ALIGNED 4 181 #define TCPOLEN_SACK_BASE 2 182 #define TCPOLEN_SACK_BASE_ALIGNED 4 183 #define TCPOLEN_SACK_PERBLOCK 8 184 #define TCPOLEN_MD5SIG_ALIGNED 20 185 186 /* Flags in tp->nonagle */ 187 #define TCP_NAGLE_OFF 1 /* Nagle's algo is disabled */ 188 #define TCP_NAGLE_CORK 2 /* Socket is corked */ 189 #define TCP_NAGLE_PUSH 4 /* Cork is overridden for already queued data */ 190 191 extern struct inet_timewait_death_row tcp_death_row; 192 193 /* sysctl variables for tcp */ 194 extern int sysctl_tcp_timestamps; 195 extern int sysctl_tcp_window_scaling; 196 extern int sysctl_tcp_sack; 197 extern int sysctl_tcp_fin_timeout; 198 extern int sysctl_tcp_keepalive_time; 199 extern int sysctl_tcp_keepalive_probes; 200 extern int sysctl_tcp_keepalive_intvl; 201 extern int sysctl_tcp_syn_retries; 202 extern int sysctl_tcp_synack_retries; 203 extern int sysctl_tcp_retries1; 204 extern int sysctl_tcp_retries2; 205 extern int sysctl_tcp_orphan_retries; 206 extern int sysctl_tcp_syncookies; 207 extern int sysctl_tcp_retrans_collapse; 208 extern int sysctl_tcp_stdurg; 209 extern int sysctl_tcp_rfc1337; 210 extern int sysctl_tcp_abort_on_overflow; 211 extern int sysctl_tcp_max_orphans; 212 extern int sysctl_tcp_fack; 213 extern int sysctl_tcp_reordering; 214 extern int sysctl_tcp_ecn; 215 extern int sysctl_tcp_dsack; 216 extern int sysctl_tcp_mem[3]; 217 extern int sysctl_tcp_wmem[3]; 218 extern int sysctl_tcp_rmem[3]; 219 extern int sysctl_tcp_app_win; 220 extern int sysctl_tcp_adv_win_scale; 221 extern int sysctl_tcp_tw_reuse; 222 extern int sysctl_tcp_frto; 223 extern int sysctl_tcp_low_latency; 224 extern int sysctl_tcp_dma_copybreak; 225 extern int sysctl_tcp_nometrics_save; 226 extern int sysctl_tcp_moderate_rcvbuf; 227 extern int sysctl_tcp_tso_win_divisor; 228 extern int sysctl_tcp_abc; 229 extern int sysctl_tcp_mtu_probing; 230 extern int sysctl_tcp_base_mss; 231 extern int sysctl_tcp_workaround_signed_windows; 232 extern int sysctl_tcp_slow_start_after_idle; 233 234 extern atomic_t tcp_memory_allocated; 235 extern atomic_t tcp_sockets_allocated; 236 extern int tcp_memory_pressure; 237 238 /* 239 * The next routines deal with comparing 32 bit unsigned ints 240 * and worry about wraparound (automatic with unsigned arithmetic). 241 */ 242 243 static inline int before(__u32 seq1, __u32 seq2) 244 { 245 return (__s32)(seq1-seq2) < 0; 246 } 247 248 static inline int after(__u32 seq1, __u32 seq2) 249 { 250 return (__s32)(seq2-seq1) < 0; 251 } 252 253 254 /* is s2<=s1<=s3 ? */ 255 static inline int between(__u32 seq1, __u32 seq2, __u32 seq3) 256 { 257 return seq3 - seq2 >= seq1 - seq2; 258 } 259 260 261 extern struct proto tcp_prot; 262 263 DECLARE_SNMP_STAT(struct tcp_mib, tcp_statistics); 264 #define TCP_INC_STATS(field) SNMP_INC_STATS(tcp_statistics, field) 265 #define TCP_INC_STATS_BH(field) SNMP_INC_STATS_BH(tcp_statistics, field) 266 #define TCP_INC_STATS_USER(field) SNMP_INC_STATS_USER(tcp_statistics, field) 267 #define TCP_DEC_STATS(field) SNMP_DEC_STATS(tcp_statistics, field) 268 #define TCP_ADD_STATS_BH(field, val) SNMP_ADD_STATS_BH(tcp_statistics, field, val) 269 #define TCP_ADD_STATS_USER(field, val) SNMP_ADD_STATS_USER(tcp_statistics, field, val) 270 271 extern void tcp_v4_err(struct sk_buff *skb, u32); 272 273 extern void tcp_shutdown (struct sock *sk, int how); 274 275 extern int tcp_v4_rcv(struct sk_buff *skb); 276 277 extern int tcp_v4_remember_stamp(struct sock *sk); 278 279 extern int tcp_v4_tw_remember_stamp(struct inet_timewait_sock *tw); 280 281 extern int tcp_sendmsg(struct kiocb *iocb, struct sock *sk, 282 struct msghdr *msg, size_t size); 283 extern ssize_t tcp_sendpage(struct socket *sock, struct page *page, int offset, size_t size, int flags); 284 285 extern int tcp_ioctl(struct sock *sk, 286 int cmd, 287 unsigned long arg); 288 289 extern int tcp_rcv_state_process(struct sock *sk, 290 struct sk_buff *skb, 291 struct tcphdr *th, 292 unsigned len); 293 294 extern int tcp_rcv_established(struct sock *sk, 295 struct sk_buff *skb, 296 struct tcphdr *th, 297 unsigned len); 298 299 extern void tcp_rcv_space_adjust(struct sock *sk); 300 301 extern void tcp_cleanup_rbuf(struct sock *sk, int copied); 302 303 extern int tcp_twsk_unique(struct sock *sk, 304 struct sock *sktw, void *twp); 305 306 extern void tcp_twsk_destructor(struct sock *sk); 307 308 static inline void tcp_dec_quickack_mode(struct sock *sk, 309 const unsigned int pkts) 310 { 311 struct inet_connection_sock *icsk = inet_csk(sk); 312 313 if (icsk->icsk_ack.quick) { 314 if (pkts >= icsk->icsk_ack.quick) { 315 icsk->icsk_ack.quick = 0; 316 /* Leaving quickack mode we deflate ATO. */ 317 icsk->icsk_ack.ato = TCP_ATO_MIN; 318 } else 319 icsk->icsk_ack.quick -= pkts; 320 } 321 } 322 323 extern void tcp_enter_quickack_mode(struct sock *sk); 324 325 static inline void tcp_clear_options(struct tcp_options_received *rx_opt) 326 { 327 rx_opt->tstamp_ok = rx_opt->sack_ok = rx_opt->wscale_ok = rx_opt->snd_wscale = 0; 328 } 329 330 enum tcp_tw_status 331 { 332 TCP_TW_SUCCESS = 0, 333 TCP_TW_RST = 1, 334 TCP_TW_ACK = 2, 335 TCP_TW_SYN = 3 336 }; 337 338 339 extern enum tcp_tw_status tcp_timewait_state_process(struct inet_timewait_sock *tw, 340 struct sk_buff *skb, 341 const struct tcphdr *th); 342 343 extern struct sock * tcp_check_req(struct sock *sk,struct sk_buff *skb, 344 struct request_sock *req, 345 struct request_sock **prev); 346 extern int tcp_child_process(struct sock *parent, 347 struct sock *child, 348 struct sk_buff *skb); 349 extern void tcp_enter_frto(struct sock *sk); 350 extern void tcp_enter_loss(struct sock *sk, int how); 351 extern void tcp_clear_retrans(struct tcp_sock *tp); 352 extern void tcp_update_metrics(struct sock *sk); 353 354 extern void tcp_close(struct sock *sk, 355 long timeout); 356 extern unsigned int tcp_poll(struct file * file, struct socket *sock, struct poll_table_struct *wait); 357 358 extern int tcp_getsockopt(struct sock *sk, int level, 359 int optname, 360 char __user *optval, 361 int __user *optlen); 362 extern int tcp_setsockopt(struct sock *sk, int level, 363 int optname, char __user *optval, 364 int optlen); 365 extern int compat_tcp_getsockopt(struct sock *sk, 366 int level, int optname, 367 char __user *optval, int __user *optlen); 368 extern int compat_tcp_setsockopt(struct sock *sk, 369 int level, int optname, 370 char __user *optval, int optlen); 371 extern void tcp_set_keepalive(struct sock *sk, int val); 372 extern int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, 373 struct msghdr *msg, 374 size_t len, int nonblock, 375 int flags, int *addr_len); 376 377 extern void tcp_parse_options(struct sk_buff *skb, 378 struct tcp_options_received *opt_rx, 379 int estab); 380 381 /* 382 * TCP v4 functions exported for the inet6 API 383 */ 384 385 extern void tcp_v4_send_check(struct sock *sk, int len, 386 struct sk_buff *skb); 387 388 extern int tcp_v4_conn_request(struct sock *sk, 389 struct sk_buff *skb); 390 391 extern struct sock * tcp_create_openreq_child(struct sock *sk, 392 struct request_sock *req, 393 struct sk_buff *skb); 394 395 extern struct sock * tcp_v4_syn_recv_sock(struct sock *sk, 396 struct sk_buff *skb, 397 struct request_sock *req, 398 struct dst_entry *dst); 399 400 extern int tcp_v4_do_rcv(struct sock *sk, 401 struct sk_buff *skb); 402 403 extern int tcp_v4_connect(struct sock *sk, 404 struct sockaddr *uaddr, 405 int addr_len); 406 407 extern int tcp_connect(struct sock *sk); 408 409 extern struct sk_buff * tcp_make_synack(struct sock *sk, 410 struct dst_entry *dst, 411 struct request_sock *req); 412 413 extern int tcp_disconnect(struct sock *sk, int flags); 414 415 extern void tcp_unhash(struct sock *sk); 416 417 /* From syncookies.c */ 418 extern struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb, 419 struct ip_options *opt); 420 extern __u32 cookie_v4_init_sequence(struct sock *sk, struct sk_buff *skb, 421 __u16 *mss); 422 423 /* tcp_output.c */ 424 425 extern void __tcp_push_pending_frames(struct sock *sk, struct tcp_sock *tp, 426 unsigned int cur_mss, int nonagle); 427 extern int tcp_may_send_now(struct sock *sk, struct tcp_sock *tp); 428 extern int tcp_retransmit_skb(struct sock *, struct sk_buff *); 429 extern void tcp_xmit_retransmit_queue(struct sock *); 430 extern void tcp_simple_retransmit(struct sock *); 431 extern int tcp_trim_head(struct sock *, struct sk_buff *, u32); 432 extern int tcp_fragment(struct sock *, struct sk_buff *, u32, unsigned int); 433 434 extern void tcp_send_probe0(struct sock *); 435 extern void tcp_send_partial(struct sock *); 436 extern int tcp_write_wakeup(struct sock *); 437 extern void tcp_send_fin(struct sock *sk); 438 extern void tcp_send_active_reset(struct sock *sk, gfp_t priority); 439 extern int tcp_send_synack(struct sock *); 440 extern void tcp_push_one(struct sock *, unsigned int mss_now); 441 extern void tcp_send_ack(struct sock *sk); 442 extern void tcp_send_delayed_ack(struct sock *sk); 443 444 /* tcp_input.c */ 445 extern void tcp_cwnd_application_limited(struct sock *sk); 446 447 /* tcp_timer.c */ 448 extern void tcp_init_xmit_timers(struct sock *); 449 static inline void tcp_clear_xmit_timers(struct sock *sk) 450 { 451 inet_csk_clear_xmit_timers(sk); 452 } 453 454 extern unsigned int tcp_sync_mss(struct sock *sk, u32 pmtu); 455 extern unsigned int tcp_current_mss(struct sock *sk, int large); 456 457 /* tcp.c */ 458 extern void tcp_get_info(struct sock *, struct tcp_info *); 459 460 /* Read 'sendfile()'-style from a TCP socket */ 461 typedef int (*sk_read_actor_t)(read_descriptor_t *, struct sk_buff *, 462 unsigned int, size_t); 463 extern int tcp_read_sock(struct sock *sk, read_descriptor_t *desc, 464 sk_read_actor_t recv_actor); 465 466 extern void tcp_initialize_rcv_mss(struct sock *sk); 467 468 extern int tcp_mtu_to_mss(struct sock *sk, int pmtu); 469 extern int tcp_mss_to_mtu(struct sock *sk, int mss); 470 extern void tcp_mtup_init(struct sock *sk); 471 472 static inline void __tcp_fast_path_on(struct tcp_sock *tp, u32 snd_wnd) 473 { 474 tp->pred_flags = htonl((tp->tcp_header_len << 26) | 475 ntohl(TCP_FLAG_ACK) | 476 snd_wnd); 477 } 478 479 static inline void tcp_fast_path_on(struct tcp_sock *tp) 480 { 481 __tcp_fast_path_on(tp, tp->snd_wnd >> tp->rx_opt.snd_wscale); 482 } 483 484 static inline void tcp_fast_path_check(struct sock *sk, struct tcp_sock *tp) 485 { 486 if (skb_queue_empty(&tp->out_of_order_queue) && 487 tp->rcv_wnd && 488 atomic_read(&sk->sk_rmem_alloc) < sk->sk_rcvbuf && 489 !tp->urg_data) 490 tcp_fast_path_on(tp); 491 } 492 493 /* Compute the actual receive window we are currently advertising. 494 * Rcv_nxt can be after the window if our peer push more data 495 * than the offered window. 496 */ 497 static inline u32 tcp_receive_window(const struct tcp_sock *tp) 498 { 499 s32 win = tp->rcv_wup + tp->rcv_wnd - tp->rcv_nxt; 500 501 if (win < 0) 502 win = 0; 503 return (u32) win; 504 } 505 506 /* Choose a new window, without checks for shrinking, and without 507 * scaling applied to the result. The caller does these things 508 * if necessary. This is a "raw" window selection. 509 */ 510 extern u32 __tcp_select_window(struct sock *sk); 511 512 /* TCP timestamps are only 32-bits, this causes a slight 513 * complication on 64-bit systems since we store a snapshot 514 * of jiffies in the buffer control blocks below. We decided 515 * to use only the low 32-bits of jiffies and hide the ugly 516 * casts with the following macro. 517 */ 518 #define tcp_time_stamp ((__u32)(jiffies)) 519 520 /* This is what the send packet queuing engine uses to pass 521 * TCP per-packet control information to the transmission 522 * code. We also store the host-order sequence numbers in 523 * here too. This is 36 bytes on 32-bit architectures, 524 * 40 bytes on 64-bit machines, if this grows please adjust 525 * skbuff.h:skbuff->cb[xxx] size appropriately. 526 */ 527 struct tcp_skb_cb { 528 union { 529 struct inet_skb_parm h4; 530 #if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE) 531 struct inet6_skb_parm h6; 532 #endif 533 } header; /* For incoming frames */ 534 __u32 seq; /* Starting sequence number */ 535 __u32 end_seq; /* SEQ + FIN + SYN + datalen */ 536 __u32 when; /* used to compute rtt's */ 537 __u8 flags; /* TCP header flags. */ 538 539 /* NOTE: These must match up to the flags byte in a 540 * real TCP header. 541 */ 542 #define TCPCB_FLAG_FIN 0x01 543 #define TCPCB_FLAG_SYN 0x02 544 #define TCPCB_FLAG_RST 0x04 545 #define TCPCB_FLAG_PSH 0x08 546 #define TCPCB_FLAG_ACK 0x10 547 #define TCPCB_FLAG_URG 0x20 548 #define TCPCB_FLAG_ECE 0x40 549 #define TCPCB_FLAG_CWR 0x80 550 551 __u8 sacked; /* State flags for SACK/FACK. */ 552 #define TCPCB_SACKED_ACKED 0x01 /* SKB ACK'd by a SACK block */ 553 #define TCPCB_SACKED_RETRANS 0x02 /* SKB retransmitted */ 554 #define TCPCB_LOST 0x04 /* SKB is lost */ 555 #define TCPCB_TAGBITS 0x07 /* All tag bits */ 556 557 #define TCPCB_EVER_RETRANS 0x80 /* Ever retransmitted frame */ 558 #define TCPCB_RETRANS (TCPCB_SACKED_RETRANS|TCPCB_EVER_RETRANS) 559 560 #define TCPCB_URG 0x20 /* Urgent pointer advanced here */ 561 562 #define TCPCB_AT_TAIL (TCPCB_URG) 563 564 __u16 urg_ptr; /* Valid w/URG flags is set. */ 565 __u32 ack_seq; /* Sequence number ACK'd */ 566 }; 567 568 #define TCP_SKB_CB(__skb) ((struct tcp_skb_cb *)&((__skb)->cb[0])) 569 570 #include <net/tcp_ecn.h> 571 572 /* Due to TSO, an SKB can be composed of multiple actual 573 * packets. To keep these tracked properly, we use this. 574 */ 575 static inline int tcp_skb_pcount(const struct sk_buff *skb) 576 { 577 return skb_shinfo(skb)->gso_segs; 578 } 579 580 /* This is valid iff tcp_skb_pcount() > 1. */ 581 static inline int tcp_skb_mss(const struct sk_buff *skb) 582 { 583 return skb_shinfo(skb)->gso_size; 584 } 585 586 static inline void tcp_dec_pcount_approx(__u32 *count, 587 const struct sk_buff *skb) 588 { 589 if (*count) { 590 *count -= tcp_skb_pcount(skb); 591 if ((int)*count < 0) 592 *count = 0; 593 } 594 } 595 596 static inline void tcp_packets_out_inc(struct sock *sk, 597 struct tcp_sock *tp, 598 const struct sk_buff *skb) 599 { 600 int orig = tp->packets_out; 601 602 tp->packets_out += tcp_skb_pcount(skb); 603 if (!orig) 604 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, 605 inet_csk(sk)->icsk_rto, TCP_RTO_MAX); 606 } 607 608 static inline void tcp_packets_out_dec(struct tcp_sock *tp, 609 const struct sk_buff *skb) 610 { 611 tp->packets_out -= tcp_skb_pcount(skb); 612 } 613 614 /* Events passed to congestion control interface */ 615 enum tcp_ca_event { 616 CA_EVENT_TX_START, /* first transmit when no packets in flight */ 617 CA_EVENT_CWND_RESTART, /* congestion window restart */ 618 CA_EVENT_COMPLETE_CWR, /* end of congestion recovery */ 619 CA_EVENT_FRTO, /* fast recovery timeout */ 620 CA_EVENT_LOSS, /* loss timeout */ 621 CA_EVENT_FAST_ACK, /* in sequence ack */ 622 CA_EVENT_SLOW_ACK, /* other ack */ 623 }; 624 625 /* 626 * Interface for adding new TCP congestion control handlers 627 */ 628 #define TCP_CA_NAME_MAX 16 629 #define TCP_CA_MAX 128 630 #define TCP_CA_BUF_MAX (TCP_CA_NAME_MAX*TCP_CA_MAX) 631 632 struct tcp_congestion_ops { 633 struct list_head list; 634 int non_restricted; 635 636 /* initialize private data (optional) */ 637 void (*init)(struct sock *sk); 638 /* cleanup private data (optional) */ 639 void (*release)(struct sock *sk); 640 641 /* return slow start threshold (required) */ 642 u32 (*ssthresh)(struct sock *sk); 643 /* lower bound for congestion window (optional) */ 644 u32 (*min_cwnd)(const struct sock *sk); 645 /* do new cwnd calculation (required) */ 646 void (*cong_avoid)(struct sock *sk, u32 ack, 647 u32 rtt, u32 in_flight, int good_ack); 648 /* round trip time sample per acked packet (optional) */ 649 void (*rtt_sample)(struct sock *sk, u32 usrtt); 650 /* call before changing ca_state (optional) */ 651 void (*set_state)(struct sock *sk, u8 new_state); 652 /* call when cwnd event occurs (optional) */ 653 void (*cwnd_event)(struct sock *sk, enum tcp_ca_event ev); 654 /* new value of cwnd after loss (optional) */ 655 u32 (*undo_cwnd)(struct sock *sk); 656 /* hook for packet ack accounting (optional) */ 657 void (*pkts_acked)(struct sock *sk, u32 num_acked); 658 /* get info for inet_diag (optional) */ 659 void (*get_info)(struct sock *sk, u32 ext, struct sk_buff *skb); 660 661 char name[TCP_CA_NAME_MAX]; 662 struct module *owner; 663 }; 664 665 extern int tcp_register_congestion_control(struct tcp_congestion_ops *type); 666 extern void tcp_unregister_congestion_control(struct tcp_congestion_ops *type); 667 668 extern void tcp_init_congestion_control(struct sock *sk); 669 extern void tcp_cleanup_congestion_control(struct sock *sk); 670 extern int tcp_set_default_congestion_control(const char *name); 671 extern void tcp_get_default_congestion_control(char *name); 672 extern void tcp_get_available_congestion_control(char *buf, size_t len); 673 extern void tcp_get_allowed_congestion_control(char *buf, size_t len); 674 extern int tcp_set_allowed_congestion_control(char *allowed); 675 extern int tcp_set_congestion_control(struct sock *sk, const char *name); 676 extern void tcp_slow_start(struct tcp_sock *tp); 677 678 extern struct tcp_congestion_ops tcp_init_congestion_ops; 679 extern u32 tcp_reno_ssthresh(struct sock *sk); 680 extern void tcp_reno_cong_avoid(struct sock *sk, u32 ack, 681 u32 rtt, u32 in_flight, int flag); 682 extern u32 tcp_reno_min_cwnd(const struct sock *sk); 683 extern struct tcp_congestion_ops tcp_reno; 684 685 static inline void tcp_set_ca_state(struct sock *sk, const u8 ca_state) 686 { 687 struct inet_connection_sock *icsk = inet_csk(sk); 688 689 if (icsk->icsk_ca_ops->set_state) 690 icsk->icsk_ca_ops->set_state(sk, ca_state); 691 icsk->icsk_ca_state = ca_state; 692 } 693 694 static inline void tcp_ca_event(struct sock *sk, const enum tcp_ca_event event) 695 { 696 const struct inet_connection_sock *icsk = inet_csk(sk); 697 698 if (icsk->icsk_ca_ops->cwnd_event) 699 icsk->icsk_ca_ops->cwnd_event(sk, event); 700 } 701 702 /* This determines how many packets are "in the network" to the best 703 * of our knowledge. In many cases it is conservative, but where 704 * detailed information is available from the receiver (via SACK 705 * blocks etc.) we can make more aggressive calculations. 706 * 707 * Use this for decisions involving congestion control, use just 708 * tp->packets_out to determine if the send queue is empty or not. 709 * 710 * Read this equation as: 711 * 712 * "Packets sent once on transmission queue" MINUS 713 * "Packets left network, but not honestly ACKed yet" PLUS 714 * "Packets fast retransmitted" 715 */ 716 static inline unsigned int tcp_packets_in_flight(const struct tcp_sock *tp) 717 { 718 return (tp->packets_out - tp->left_out + tp->retrans_out); 719 } 720 721 /* If cwnd > ssthresh, we may raise ssthresh to be half-way to cwnd. 722 * The exception is rate halving phase, when cwnd is decreasing towards 723 * ssthresh. 724 */ 725 static inline __u32 tcp_current_ssthresh(const struct sock *sk) 726 { 727 const struct tcp_sock *tp = tcp_sk(sk); 728 if ((1 << inet_csk(sk)->icsk_ca_state) & (TCPF_CA_CWR | TCPF_CA_Recovery)) 729 return tp->snd_ssthresh; 730 else 731 return max(tp->snd_ssthresh, 732 ((tp->snd_cwnd >> 1) + 733 (tp->snd_cwnd >> 2))); 734 } 735 736 static inline void tcp_sync_left_out(struct tcp_sock *tp) 737 { 738 if (tp->rx_opt.sack_ok && 739 (tp->sacked_out >= tp->packets_out - tp->lost_out)) 740 tp->sacked_out = tp->packets_out - tp->lost_out; 741 tp->left_out = tp->sacked_out + tp->lost_out; 742 } 743 744 extern void tcp_enter_cwr(struct sock *sk); 745 extern __u32 tcp_init_cwnd(struct tcp_sock *tp, struct dst_entry *dst); 746 747 /* Slow start with delack produces 3 packets of burst, so that 748 * it is safe "de facto". 749 */ 750 static __inline__ __u32 tcp_max_burst(const struct tcp_sock *tp) 751 { 752 return 3; 753 } 754 755 /* RFC2861 Check whether we are limited by application or congestion window 756 * This is the inverse of cwnd check in tcp_tso_should_defer 757 */ 758 static inline int tcp_is_cwnd_limited(const struct sock *sk, u32 in_flight) 759 { 760 const struct tcp_sock *tp = tcp_sk(sk); 761 u32 left; 762 763 if (in_flight >= tp->snd_cwnd) 764 return 1; 765 766 if (!sk_can_gso(sk)) 767 return 0; 768 769 left = tp->snd_cwnd - in_flight; 770 if (sysctl_tcp_tso_win_divisor) 771 return left * sysctl_tcp_tso_win_divisor < tp->snd_cwnd; 772 else 773 return left <= tcp_max_burst(tp); 774 } 775 776 static inline void tcp_minshall_update(struct tcp_sock *tp, int mss, 777 const struct sk_buff *skb) 778 { 779 if (skb->len < mss) 780 tp->snd_sml = TCP_SKB_CB(skb)->end_seq; 781 } 782 783 static inline void tcp_check_probe_timer(struct sock *sk, struct tcp_sock *tp) 784 { 785 const struct inet_connection_sock *icsk = inet_csk(sk); 786 if (!tp->packets_out && !icsk->icsk_pending) 787 inet_csk_reset_xmit_timer(sk, ICSK_TIME_PROBE0, 788 icsk->icsk_rto, TCP_RTO_MAX); 789 } 790 791 static inline void tcp_push_pending_frames(struct sock *sk, 792 struct tcp_sock *tp) 793 { 794 __tcp_push_pending_frames(sk, tp, tcp_current_mss(sk, 1), tp->nonagle); 795 } 796 797 static inline void tcp_init_wl(struct tcp_sock *tp, u32 ack, u32 seq) 798 { 799 tp->snd_wl1 = seq; 800 } 801 802 static inline void tcp_update_wl(struct tcp_sock *tp, u32 ack, u32 seq) 803 { 804 tp->snd_wl1 = seq; 805 } 806 807 /* 808 * Calculate(/check) TCP checksum 809 */ 810 static inline __sum16 tcp_v4_check(struct tcphdr *th, int len, 811 __be32 saddr, __be32 daddr, 812 __wsum base) 813 { 814 return csum_tcpudp_magic(saddr,daddr,len,IPPROTO_TCP,base); 815 } 816 817 static inline __sum16 __tcp_checksum_complete(struct sk_buff *skb) 818 { 819 return __skb_checksum_complete(skb); 820 } 821 822 static inline int tcp_checksum_complete(struct sk_buff *skb) 823 { 824 return skb->ip_summed != CHECKSUM_UNNECESSARY && 825 __tcp_checksum_complete(skb); 826 } 827 828 /* Prequeue for VJ style copy to user, combined with checksumming. */ 829 830 static inline void tcp_prequeue_init(struct tcp_sock *tp) 831 { 832 tp->ucopy.task = NULL; 833 tp->ucopy.len = 0; 834 tp->ucopy.memory = 0; 835 skb_queue_head_init(&tp->ucopy.prequeue); 836 #ifdef CONFIG_NET_DMA 837 tp->ucopy.dma_chan = NULL; 838 tp->ucopy.wakeup = 0; 839 tp->ucopy.pinned_list = NULL; 840 tp->ucopy.dma_cookie = 0; 841 #endif 842 } 843 844 /* Packet is added to VJ-style prequeue for processing in process 845 * context, if a reader task is waiting. Apparently, this exciting 846 * idea (VJ's mail "Re: query about TCP header on tcp-ip" of 07 Sep 93) 847 * failed somewhere. Latency? Burstiness? Well, at least now we will 848 * see, why it failed. 8)8) --ANK 849 * 850 * NOTE: is this not too big to inline? 851 */ 852 static inline int tcp_prequeue(struct sock *sk, struct sk_buff *skb) 853 { 854 struct tcp_sock *tp = tcp_sk(sk); 855 856 if (!sysctl_tcp_low_latency && tp->ucopy.task) { 857 __skb_queue_tail(&tp->ucopy.prequeue, skb); 858 tp->ucopy.memory += skb->truesize; 859 if (tp->ucopy.memory > sk->sk_rcvbuf) { 860 struct sk_buff *skb1; 861 862 BUG_ON(sock_owned_by_user(sk)); 863 864 while ((skb1 = __skb_dequeue(&tp->ucopy.prequeue)) != NULL) { 865 sk->sk_backlog_rcv(sk, skb1); 866 NET_INC_STATS_BH(LINUX_MIB_TCPPREQUEUEDROPPED); 867 } 868 869 tp->ucopy.memory = 0; 870 } else if (skb_queue_len(&tp->ucopy.prequeue) == 1) { 871 wake_up_interruptible(sk->sk_sleep); 872 if (!inet_csk_ack_scheduled(sk)) 873 inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK, 874 (3 * TCP_RTO_MIN) / 4, 875 TCP_RTO_MAX); 876 } 877 return 1; 878 } 879 return 0; 880 } 881 882 883 #undef STATE_TRACE 884 885 #ifdef STATE_TRACE 886 static const char *statename[]={ 887 "Unused","Established","Syn Sent","Syn Recv", 888 "Fin Wait 1","Fin Wait 2","Time Wait", "Close", 889 "Close Wait","Last ACK","Listen","Closing" 890 }; 891 #endif 892 893 static inline void tcp_set_state(struct sock *sk, int state) 894 { 895 int oldstate = sk->sk_state; 896 897 switch (state) { 898 case TCP_ESTABLISHED: 899 if (oldstate != TCP_ESTABLISHED) 900 TCP_INC_STATS(TCP_MIB_CURRESTAB); 901 break; 902 903 case TCP_CLOSE: 904 if (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED) 905 TCP_INC_STATS(TCP_MIB_ESTABRESETS); 906 907 sk->sk_prot->unhash(sk); 908 if (inet_csk(sk)->icsk_bind_hash && 909 !(sk->sk_userlocks & SOCK_BINDPORT_LOCK)) 910 inet_put_port(&tcp_hashinfo, sk); 911 /* fall through */ 912 default: 913 if (oldstate==TCP_ESTABLISHED) 914 TCP_DEC_STATS(TCP_MIB_CURRESTAB); 915 } 916 917 /* Change state AFTER socket is unhashed to avoid closed 918 * socket sitting in hash tables. 919 */ 920 sk->sk_state = state; 921 922 #ifdef STATE_TRACE 923 SOCK_DEBUG(sk, "TCP sk=%p, State %s -> %s\n",sk, statename[oldstate],statename[state]); 924 #endif 925 } 926 927 static inline void tcp_done(struct sock *sk) 928 { 929 if(sk->sk_state == TCP_SYN_SENT || sk->sk_state == TCP_SYN_RECV) 930 TCP_INC_STATS_BH(TCP_MIB_ATTEMPTFAILS); 931 932 tcp_set_state(sk, TCP_CLOSE); 933 tcp_clear_xmit_timers(sk); 934 935 sk->sk_shutdown = SHUTDOWN_MASK; 936 937 if (!sock_flag(sk, SOCK_DEAD)) 938 sk->sk_state_change(sk); 939 else 940 inet_csk_destroy_sock(sk); 941 } 942 943 static inline void tcp_sack_reset(struct tcp_options_received *rx_opt) 944 { 945 rx_opt->dsack = 0; 946 rx_opt->eff_sacks = 0; 947 rx_opt->num_sacks = 0; 948 } 949 950 /* Determine a window scaling and initial window to offer. */ 951 extern void tcp_select_initial_window(int __space, __u32 mss, 952 __u32 *rcv_wnd, __u32 *window_clamp, 953 int wscale_ok, __u8 *rcv_wscale); 954 955 static inline int tcp_win_from_space(int space) 956 { 957 return sysctl_tcp_adv_win_scale<=0 ? 958 (space>>(-sysctl_tcp_adv_win_scale)) : 959 space - (space>>sysctl_tcp_adv_win_scale); 960 } 961 962 /* Note: caller must be prepared to deal with negative returns */ 963 static inline int tcp_space(const struct sock *sk) 964 { 965 return tcp_win_from_space(sk->sk_rcvbuf - 966 atomic_read(&sk->sk_rmem_alloc)); 967 } 968 969 static inline int tcp_full_space(const struct sock *sk) 970 { 971 return tcp_win_from_space(sk->sk_rcvbuf); 972 } 973 974 static inline void tcp_openreq_init(struct request_sock *req, 975 struct tcp_options_received *rx_opt, 976 struct sk_buff *skb) 977 { 978 struct inet_request_sock *ireq = inet_rsk(req); 979 980 req->rcv_wnd = 0; /* So that tcp_send_synack() knows! */ 981 tcp_rsk(req)->rcv_isn = TCP_SKB_CB(skb)->seq; 982 req->mss = rx_opt->mss_clamp; 983 req->ts_recent = rx_opt->saw_tstamp ? rx_opt->rcv_tsval : 0; 984 ireq->tstamp_ok = rx_opt->tstamp_ok; 985 ireq->sack_ok = rx_opt->sack_ok; 986 ireq->snd_wscale = rx_opt->snd_wscale; 987 ireq->wscale_ok = rx_opt->wscale_ok; 988 ireq->acked = 0; 989 ireq->ecn_ok = 0; 990 ireq->rmt_port = skb->h.th->source; 991 } 992 993 extern void tcp_enter_memory_pressure(void); 994 995 static inline int keepalive_intvl_when(const struct tcp_sock *tp) 996 { 997 return tp->keepalive_intvl ? : sysctl_tcp_keepalive_intvl; 998 } 999 1000 static inline int keepalive_time_when(const struct tcp_sock *tp) 1001 { 1002 return tp->keepalive_time ? : sysctl_tcp_keepalive_time; 1003 } 1004 1005 static inline int tcp_fin_time(const struct sock *sk) 1006 { 1007 int fin_timeout = tcp_sk(sk)->linger2 ? : sysctl_tcp_fin_timeout; 1008 const int rto = inet_csk(sk)->icsk_rto; 1009 1010 if (fin_timeout < (rto << 2) - (rto >> 1)) 1011 fin_timeout = (rto << 2) - (rto >> 1); 1012 1013 return fin_timeout; 1014 } 1015 1016 static inline int tcp_paws_check(const struct tcp_options_received *rx_opt, int rst) 1017 { 1018 if ((s32)(rx_opt->rcv_tsval - rx_opt->ts_recent) >= 0) 1019 return 0; 1020 if (xtime.tv_sec >= rx_opt->ts_recent_stamp + TCP_PAWS_24DAYS) 1021 return 0; 1022 1023 /* RST segments are not recommended to carry timestamp, 1024 and, if they do, it is recommended to ignore PAWS because 1025 "their cleanup function should take precedence over timestamps." 1026 Certainly, it is mistake. It is necessary to understand the reasons 1027 of this constraint to relax it: if peer reboots, clock may go 1028 out-of-sync and half-open connections will not be reset. 1029 Actually, the problem would be not existing if all 1030 the implementations followed draft about maintaining clock 1031 via reboots. Linux-2.2 DOES NOT! 1032 1033 However, we can relax time bounds for RST segments to MSL. 1034 */ 1035 if (rst && xtime.tv_sec >= rx_opt->ts_recent_stamp + TCP_PAWS_MSL) 1036 return 0; 1037 return 1; 1038 } 1039 1040 #define TCP_CHECK_TIMER(sk) do { } while (0) 1041 1042 static inline int tcp_use_frto(const struct sock *sk) 1043 { 1044 const struct tcp_sock *tp = tcp_sk(sk); 1045 1046 /* F-RTO must be activated in sysctl and there must be some 1047 * unsent new data, and the advertised window should allow 1048 * sending it. 1049 */ 1050 return (sysctl_tcp_frto && sk->sk_send_head && 1051 !after(TCP_SKB_CB(sk->sk_send_head)->end_seq, 1052 tp->snd_una + tp->snd_wnd)); 1053 } 1054 1055 static inline void tcp_mib_init(void) 1056 { 1057 /* See RFC 2012 */ 1058 TCP_ADD_STATS_USER(TCP_MIB_RTOALGORITHM, 1); 1059 TCP_ADD_STATS_USER(TCP_MIB_RTOMIN, TCP_RTO_MIN*1000/HZ); 1060 TCP_ADD_STATS_USER(TCP_MIB_RTOMAX, TCP_RTO_MAX*1000/HZ); 1061 TCP_ADD_STATS_USER(TCP_MIB_MAXCONN, -1); 1062 } 1063 1064 /*from STCP */ 1065 static inline void clear_all_retrans_hints(struct tcp_sock *tp){ 1066 tp->lost_skb_hint = NULL; 1067 tp->scoreboard_skb_hint = NULL; 1068 tp->retransmit_skb_hint = NULL; 1069 tp->forward_skb_hint = NULL; 1070 tp->fastpath_skb_hint = NULL; 1071 } 1072 1073 /* MD5 Signature */ 1074 struct crypto_hash; 1075 1076 /* - key database */ 1077 struct tcp_md5sig_key { 1078 u8 *key; 1079 u8 keylen; 1080 }; 1081 1082 struct tcp4_md5sig_key { 1083 u8 *key; 1084 u16 keylen; 1085 __be32 addr; 1086 }; 1087 1088 struct tcp6_md5sig_key { 1089 u8 *key; 1090 u16 keylen; 1091 #if 0 1092 u32 scope_id; /* XXX */ 1093 #endif 1094 struct in6_addr addr; 1095 }; 1096 1097 /* - sock block */ 1098 struct tcp_md5sig_info { 1099 struct tcp4_md5sig_key *keys4; 1100 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) 1101 struct tcp6_md5sig_key *keys6; 1102 u32 entries6; 1103 u32 alloced6; 1104 #endif 1105 u32 entries4; 1106 u32 alloced4; 1107 }; 1108 1109 /* - pseudo header */ 1110 struct tcp4_pseudohdr { 1111 __be32 saddr; 1112 __be32 daddr; 1113 __u8 pad; 1114 __u8 protocol; 1115 __be16 len; 1116 }; 1117 1118 struct tcp6_pseudohdr { 1119 struct in6_addr saddr; 1120 struct in6_addr daddr; 1121 __be32 len; 1122 __be32 protocol; /* including padding */ 1123 }; 1124 1125 union tcp_md5sum_block { 1126 struct tcp4_pseudohdr ip4; 1127 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) 1128 struct tcp6_pseudohdr ip6; 1129 #endif 1130 }; 1131 1132 /* - pool: digest algorithm, hash description and scratch buffer */ 1133 struct tcp_md5sig_pool { 1134 struct hash_desc md5_desc; 1135 union tcp_md5sum_block md5_blk; 1136 }; 1137 1138 #define TCP_MD5SIG_MAXKEYS (~(u32)0) /* really?! */ 1139 1140 /* - functions */ 1141 extern int tcp_v4_calc_md5_hash(char *md5_hash, 1142 struct tcp_md5sig_key *key, 1143 struct sock *sk, 1144 struct dst_entry *dst, 1145 struct request_sock *req, 1146 struct tcphdr *th, 1147 int protocol, int tcplen); 1148 extern struct tcp_md5sig_key *tcp_v4_md5_lookup(struct sock *sk, 1149 struct sock *addr_sk); 1150 1151 extern int tcp_v4_md5_do_add(struct sock *sk, 1152 __be32 addr, 1153 u8 *newkey, 1154 u8 newkeylen); 1155 1156 extern int tcp_v4_md5_do_del(struct sock *sk, 1157 __be32 addr); 1158 1159 extern struct tcp_md5sig_pool **tcp_alloc_md5sig_pool(void); 1160 extern void tcp_free_md5sig_pool(void); 1161 1162 extern struct tcp_md5sig_pool *__tcp_get_md5sig_pool(int cpu); 1163 extern void __tcp_put_md5sig_pool(void); 1164 1165 static inline 1166 struct tcp_md5sig_pool *tcp_get_md5sig_pool(void) 1167 { 1168 int cpu = get_cpu(); 1169 struct tcp_md5sig_pool *ret = __tcp_get_md5sig_pool(cpu); 1170 if (!ret) 1171 put_cpu(); 1172 return ret; 1173 } 1174 1175 static inline void tcp_put_md5sig_pool(void) 1176 { 1177 __tcp_put_md5sig_pool(); 1178 put_cpu(); 1179 } 1180 1181 /* /proc */ 1182 enum tcp_seq_states { 1183 TCP_SEQ_STATE_LISTENING, 1184 TCP_SEQ_STATE_OPENREQ, 1185 TCP_SEQ_STATE_ESTABLISHED, 1186 TCP_SEQ_STATE_TIME_WAIT, 1187 }; 1188 1189 struct tcp_seq_afinfo { 1190 struct module *owner; 1191 char *name; 1192 sa_family_t family; 1193 int (*seq_show) (struct seq_file *m, void *v); 1194 struct file_operations *seq_fops; 1195 }; 1196 1197 struct tcp_iter_state { 1198 sa_family_t family; 1199 enum tcp_seq_states state; 1200 struct sock *syn_wait_sk; 1201 int bucket, sbucket, num, uid; 1202 struct seq_operations seq_ops; 1203 }; 1204 1205 extern int tcp_proc_register(struct tcp_seq_afinfo *afinfo); 1206 extern void tcp_proc_unregister(struct tcp_seq_afinfo *afinfo); 1207 1208 extern struct request_sock_ops tcp_request_sock_ops; 1209 1210 extern int tcp_v4_destroy_sock(struct sock *sk); 1211 1212 extern int tcp_v4_gso_send_check(struct sk_buff *skb); 1213 extern struct sk_buff *tcp_tso_segment(struct sk_buff *skb, int features); 1214 1215 #ifdef CONFIG_PROC_FS 1216 extern int tcp4_proc_init(void); 1217 extern void tcp4_proc_exit(void); 1218 #endif 1219 1220 /* TCP af-specific functions */ 1221 struct tcp_sock_af_ops { 1222 #ifdef CONFIG_TCP_MD5SIG 1223 struct tcp_md5sig_key *(*md5_lookup) (struct sock *sk, 1224 struct sock *addr_sk); 1225 int (*calc_md5_hash) (char *location, 1226 struct tcp_md5sig_key *md5, 1227 struct sock *sk, 1228 struct dst_entry *dst, 1229 struct request_sock *req, 1230 struct tcphdr *th, 1231 int protocol, int len); 1232 int (*md5_add) (struct sock *sk, 1233 struct sock *addr_sk, 1234 u8 *newkey, 1235 u8 len); 1236 int (*md5_parse) (struct sock *sk, 1237 char __user *optval, 1238 int optlen); 1239 #endif 1240 }; 1241 1242 struct tcp_request_sock_ops { 1243 #ifdef CONFIG_TCP_MD5SIG 1244 struct tcp_md5sig_key *(*md5_lookup) (struct sock *sk, 1245 struct request_sock *req); 1246 #endif 1247 }; 1248 1249 extern void tcp_v4_init(struct net_proto_family *ops); 1250 extern void tcp_init(void); 1251 1252 #endif /* _TCP_H */ 1253