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