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_frto_response; 224 extern int sysctl_tcp_low_latency; 225 extern int sysctl_tcp_dma_copybreak; 226 extern int sysctl_tcp_nometrics_save; 227 extern int sysctl_tcp_moderate_rcvbuf; 228 extern int sysctl_tcp_tso_win_divisor; 229 extern int sysctl_tcp_abc; 230 extern int sysctl_tcp_mtu_probing; 231 extern int sysctl_tcp_base_mss; 232 extern int sysctl_tcp_workaround_signed_windows; 233 extern int sysctl_tcp_slow_start_after_idle; 234 extern int sysctl_tcp_max_ssthresh; 235 236 extern atomic_t tcp_memory_allocated; 237 extern atomic_t tcp_sockets_allocated; 238 extern int tcp_memory_pressure; 239 240 /* 241 * The next routines deal with comparing 32 bit unsigned ints 242 * and worry about wraparound (automatic with unsigned arithmetic). 243 */ 244 245 static inline int before(__u32 seq1, __u32 seq2) 246 { 247 return (__s32)(seq1-seq2) < 0; 248 } 249 #define after(seq2, seq1) before(seq1, seq2) 250 251 /* is s2<=s1<=s3 ? */ 252 static inline int between(__u32 seq1, __u32 seq2, __u32 seq3) 253 { 254 return seq3 - seq2 >= seq1 - seq2; 255 } 256 257 static inline int tcp_too_many_orphans(struct sock *sk, int num) 258 { 259 return (num > sysctl_tcp_max_orphans) || 260 (sk->sk_wmem_queued > SOCK_MIN_SNDBUF && 261 atomic_read(&tcp_memory_allocated) > sysctl_tcp_mem[2]); 262 } 263 264 extern struct proto tcp_prot; 265 266 DECLARE_SNMP_STAT(struct tcp_mib, tcp_statistics); 267 #define TCP_INC_STATS(field) SNMP_INC_STATS(tcp_statistics, field) 268 #define TCP_INC_STATS_BH(field) SNMP_INC_STATS_BH(tcp_statistics, field) 269 #define TCP_INC_STATS_USER(field) SNMP_INC_STATS_USER(tcp_statistics, field) 270 #define TCP_DEC_STATS(field) SNMP_DEC_STATS(tcp_statistics, field) 271 #define TCP_ADD_STATS_BH(field, val) SNMP_ADD_STATS_BH(tcp_statistics, field, val) 272 #define TCP_ADD_STATS_USER(field, val) SNMP_ADD_STATS_USER(tcp_statistics, field, val) 273 274 extern void tcp_v4_err(struct sk_buff *skb, u32); 275 276 extern void tcp_shutdown (struct sock *sk, int how); 277 278 extern int tcp_v4_rcv(struct sk_buff *skb); 279 280 extern int tcp_v4_remember_stamp(struct sock *sk); 281 282 extern int tcp_v4_tw_remember_stamp(struct inet_timewait_sock *tw); 283 284 extern int tcp_sendmsg(struct kiocb *iocb, struct sock *sk, 285 struct msghdr *msg, size_t size); 286 extern ssize_t tcp_sendpage(struct socket *sock, struct page *page, int offset, size_t size, int flags); 287 288 extern int tcp_ioctl(struct sock *sk, 289 int cmd, 290 unsigned long arg); 291 292 extern int tcp_rcv_state_process(struct sock *sk, 293 struct sk_buff *skb, 294 struct tcphdr *th, 295 unsigned len); 296 297 extern int tcp_rcv_established(struct sock *sk, 298 struct sk_buff *skb, 299 struct tcphdr *th, 300 unsigned len); 301 302 extern void tcp_rcv_space_adjust(struct sock *sk); 303 304 extern void tcp_cleanup_rbuf(struct sock *sk, int copied); 305 306 extern int tcp_twsk_unique(struct sock *sk, 307 struct sock *sktw, void *twp); 308 309 extern void tcp_twsk_destructor(struct sock *sk); 310 311 static inline void tcp_dec_quickack_mode(struct sock *sk, 312 const unsigned int pkts) 313 { 314 struct inet_connection_sock *icsk = inet_csk(sk); 315 316 if (icsk->icsk_ack.quick) { 317 if (pkts >= icsk->icsk_ack.quick) { 318 icsk->icsk_ack.quick = 0; 319 /* Leaving quickack mode we deflate ATO. */ 320 icsk->icsk_ack.ato = TCP_ATO_MIN; 321 } else 322 icsk->icsk_ack.quick -= pkts; 323 } 324 } 325 326 extern void tcp_enter_quickack_mode(struct sock *sk); 327 328 static inline void tcp_clear_options(struct tcp_options_received *rx_opt) 329 { 330 rx_opt->tstamp_ok = rx_opt->sack_ok = rx_opt->wscale_ok = rx_opt->snd_wscale = 0; 331 } 332 333 enum tcp_tw_status 334 { 335 TCP_TW_SUCCESS = 0, 336 TCP_TW_RST = 1, 337 TCP_TW_ACK = 2, 338 TCP_TW_SYN = 3 339 }; 340 341 342 extern enum tcp_tw_status tcp_timewait_state_process(struct inet_timewait_sock *tw, 343 struct sk_buff *skb, 344 const struct tcphdr *th); 345 346 extern struct sock * tcp_check_req(struct sock *sk,struct sk_buff *skb, 347 struct request_sock *req, 348 struct request_sock **prev); 349 extern int tcp_child_process(struct sock *parent, 350 struct sock *child, 351 struct sk_buff *skb); 352 extern int tcp_use_frto(struct sock *sk); 353 extern void tcp_enter_frto(struct sock *sk); 354 extern void tcp_enter_loss(struct sock *sk, int how); 355 extern void tcp_clear_retrans(struct tcp_sock *tp); 356 extern void tcp_update_metrics(struct sock *sk); 357 358 extern void tcp_close(struct sock *sk, 359 long timeout); 360 extern unsigned int tcp_poll(struct file * file, struct socket *sock, struct poll_table_struct *wait); 361 362 extern int tcp_getsockopt(struct sock *sk, int level, 363 int optname, 364 char __user *optval, 365 int __user *optlen); 366 extern int tcp_setsockopt(struct sock *sk, int level, 367 int optname, char __user *optval, 368 int optlen); 369 extern int compat_tcp_getsockopt(struct sock *sk, 370 int level, int optname, 371 char __user *optval, int __user *optlen); 372 extern int compat_tcp_setsockopt(struct sock *sk, 373 int level, int optname, 374 char __user *optval, int optlen); 375 extern void tcp_set_keepalive(struct sock *sk, int val); 376 extern int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, 377 struct msghdr *msg, 378 size_t len, int nonblock, 379 int flags, int *addr_len); 380 381 extern void tcp_parse_options(struct sk_buff *skb, 382 struct tcp_options_received *opt_rx, 383 int estab); 384 385 /* 386 * TCP v4 functions exported for the inet6 API 387 */ 388 389 extern void tcp_v4_send_check(struct sock *sk, int len, 390 struct sk_buff *skb); 391 392 extern int tcp_v4_conn_request(struct sock *sk, 393 struct sk_buff *skb); 394 395 extern struct sock * tcp_create_openreq_child(struct sock *sk, 396 struct request_sock *req, 397 struct sk_buff *skb); 398 399 extern struct sock * tcp_v4_syn_recv_sock(struct sock *sk, 400 struct sk_buff *skb, 401 struct request_sock *req, 402 struct dst_entry *dst); 403 404 extern int tcp_v4_do_rcv(struct sock *sk, 405 struct sk_buff *skb); 406 407 extern int tcp_v4_connect(struct sock *sk, 408 struct sockaddr *uaddr, 409 int addr_len); 410 411 extern int tcp_connect(struct sock *sk); 412 413 extern struct sk_buff * tcp_make_synack(struct sock *sk, 414 struct dst_entry *dst, 415 struct request_sock *req); 416 417 extern int tcp_disconnect(struct sock *sk, int flags); 418 419 extern void tcp_unhash(struct sock *sk); 420 421 /* From syncookies.c */ 422 extern struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb, 423 struct ip_options *opt); 424 extern __u32 cookie_v4_init_sequence(struct sock *sk, struct sk_buff *skb, 425 __u16 *mss); 426 427 /* tcp_output.c */ 428 429 extern void __tcp_push_pending_frames(struct sock *sk, unsigned int cur_mss, 430 int nonagle); 431 extern int tcp_may_send_now(struct sock *sk); 432 extern int tcp_retransmit_skb(struct sock *, struct sk_buff *); 433 extern void tcp_xmit_retransmit_queue(struct sock *); 434 extern void tcp_simple_retransmit(struct sock *); 435 extern int tcp_trim_head(struct sock *, struct sk_buff *, u32); 436 extern int tcp_fragment(struct sock *, struct sk_buff *, u32, unsigned int); 437 438 extern void tcp_send_probe0(struct sock *); 439 extern void tcp_send_partial(struct sock *); 440 extern int tcp_write_wakeup(struct sock *); 441 extern void tcp_send_fin(struct sock *sk); 442 extern void tcp_send_active_reset(struct sock *sk, gfp_t priority); 443 extern int tcp_send_synack(struct sock *); 444 extern void tcp_push_one(struct sock *, unsigned int mss_now); 445 extern void tcp_send_ack(struct sock *sk); 446 extern void tcp_send_delayed_ack(struct sock *sk); 447 448 /* tcp_input.c */ 449 extern void tcp_cwnd_application_limited(struct sock *sk); 450 451 /* tcp_timer.c */ 452 extern void tcp_init_xmit_timers(struct sock *); 453 static inline void tcp_clear_xmit_timers(struct sock *sk) 454 { 455 inet_csk_clear_xmit_timers(sk); 456 } 457 458 extern unsigned int tcp_sync_mss(struct sock *sk, u32 pmtu); 459 extern unsigned int tcp_current_mss(struct sock *sk, int large); 460 461 /* tcp.c */ 462 extern void tcp_get_info(struct sock *, struct tcp_info *); 463 464 /* Read 'sendfile()'-style from a TCP socket */ 465 typedef int (*sk_read_actor_t)(read_descriptor_t *, struct sk_buff *, 466 unsigned int, size_t); 467 extern int tcp_read_sock(struct sock *sk, read_descriptor_t *desc, 468 sk_read_actor_t recv_actor); 469 470 extern void tcp_initialize_rcv_mss(struct sock *sk); 471 472 extern int tcp_mtu_to_mss(struct sock *sk, int pmtu); 473 extern int tcp_mss_to_mtu(struct sock *sk, int mss); 474 extern void tcp_mtup_init(struct sock *sk); 475 476 static inline void __tcp_fast_path_on(struct tcp_sock *tp, u32 snd_wnd) 477 { 478 tp->pred_flags = htonl((tp->tcp_header_len << 26) | 479 ntohl(TCP_FLAG_ACK) | 480 snd_wnd); 481 } 482 483 static inline void tcp_fast_path_on(struct tcp_sock *tp) 484 { 485 __tcp_fast_path_on(tp, tp->snd_wnd >> tp->rx_opt.snd_wscale); 486 } 487 488 static inline void tcp_fast_path_check(struct sock *sk) 489 { 490 struct tcp_sock *tp = tcp_sk(sk); 491 492 if (skb_queue_empty(&tp->out_of_order_queue) && 493 tp->rcv_wnd && 494 atomic_read(&sk->sk_rmem_alloc) < sk->sk_rcvbuf && 495 !tp->urg_data) 496 tcp_fast_path_on(tp); 497 } 498 499 /* Compute the actual receive window we are currently advertising. 500 * Rcv_nxt can be after the window if our peer push more data 501 * than the offered window. 502 */ 503 static inline u32 tcp_receive_window(const struct tcp_sock *tp) 504 { 505 s32 win = tp->rcv_wup + tp->rcv_wnd - tp->rcv_nxt; 506 507 if (win < 0) 508 win = 0; 509 return (u32) win; 510 } 511 512 /* Choose a new window, without checks for shrinking, and without 513 * scaling applied to the result. The caller does these things 514 * if necessary. This is a "raw" window selection. 515 */ 516 extern u32 __tcp_select_window(struct sock *sk); 517 518 /* TCP timestamps are only 32-bits, this causes a slight 519 * complication on 64-bit systems since we store a snapshot 520 * of jiffies in the buffer control blocks below. We decided 521 * to use only the low 32-bits of jiffies and hide the ugly 522 * casts with the following macro. 523 */ 524 #define tcp_time_stamp ((__u32)(jiffies)) 525 526 /* This is what the send packet queuing engine uses to pass 527 * TCP per-packet control information to the transmission 528 * code. We also store the host-order sequence numbers in 529 * here too. This is 36 bytes on 32-bit architectures, 530 * 40 bytes on 64-bit machines, if this grows please adjust 531 * skbuff.h:skbuff->cb[xxx] size appropriately. 532 */ 533 struct tcp_skb_cb { 534 union { 535 struct inet_skb_parm h4; 536 #if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE) 537 struct inet6_skb_parm h6; 538 #endif 539 } header; /* For incoming frames */ 540 __u32 seq; /* Starting sequence number */ 541 __u32 end_seq; /* SEQ + FIN + SYN + datalen */ 542 __u32 when; /* used to compute rtt's */ 543 __u8 flags; /* TCP header flags. */ 544 545 /* NOTE: These must match up to the flags byte in a 546 * real TCP header. 547 */ 548 #define TCPCB_FLAG_FIN 0x01 549 #define TCPCB_FLAG_SYN 0x02 550 #define TCPCB_FLAG_RST 0x04 551 #define TCPCB_FLAG_PSH 0x08 552 #define TCPCB_FLAG_ACK 0x10 553 #define TCPCB_FLAG_URG 0x20 554 #define TCPCB_FLAG_ECE 0x40 555 #define TCPCB_FLAG_CWR 0x80 556 557 __u8 sacked; /* State flags for SACK/FACK. */ 558 #define TCPCB_SACKED_ACKED 0x01 /* SKB ACK'd by a SACK block */ 559 #define TCPCB_SACKED_RETRANS 0x02 /* SKB retransmitted */ 560 #define TCPCB_LOST 0x04 /* SKB is lost */ 561 #define TCPCB_TAGBITS 0x07 /* All tag bits */ 562 563 #define TCPCB_EVER_RETRANS 0x80 /* Ever retransmitted frame */ 564 #define TCPCB_RETRANS (TCPCB_SACKED_RETRANS|TCPCB_EVER_RETRANS) 565 566 #define TCPCB_URG 0x20 /* Urgent pointer advanced here */ 567 568 #define TCPCB_AT_TAIL (TCPCB_URG) 569 570 __u16 urg_ptr; /* Valid w/URG flags is set. */ 571 __u32 ack_seq; /* Sequence number ACK'd */ 572 }; 573 574 #define TCP_SKB_CB(__skb) ((struct tcp_skb_cb *)&((__skb)->cb[0])) 575 576 #include <net/tcp_ecn.h> 577 578 /* Due to TSO, an SKB can be composed of multiple actual 579 * packets. To keep these tracked properly, we use this. 580 */ 581 static inline int tcp_skb_pcount(const struct sk_buff *skb) 582 { 583 return skb_shinfo(skb)->gso_segs; 584 } 585 586 /* This is valid iff tcp_skb_pcount() > 1. */ 587 static inline int tcp_skb_mss(const struct sk_buff *skb) 588 { 589 return skb_shinfo(skb)->gso_size; 590 } 591 592 static inline void tcp_dec_pcount_approx(__u32 *count, 593 const struct sk_buff *skb) 594 { 595 if (*count) { 596 *count -= tcp_skb_pcount(skb); 597 if ((int)*count < 0) 598 *count = 0; 599 } 600 } 601 602 static inline void tcp_packets_out_inc(struct sock *sk, 603 const struct sk_buff *skb) 604 { 605 struct tcp_sock *tp = tcp_sk(sk); 606 int orig = tp->packets_out; 607 608 tp->packets_out += tcp_skb_pcount(skb); 609 if (!orig) 610 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, 611 inet_csk(sk)->icsk_rto, TCP_RTO_MAX); 612 } 613 614 static inline void tcp_packets_out_dec(struct tcp_sock *tp, 615 const struct sk_buff *skb) 616 { 617 tp->packets_out -= tcp_skb_pcount(skb); 618 } 619 620 /* Events passed to congestion control interface */ 621 enum tcp_ca_event { 622 CA_EVENT_TX_START, /* first transmit when no packets in flight */ 623 CA_EVENT_CWND_RESTART, /* congestion window restart */ 624 CA_EVENT_COMPLETE_CWR, /* end of congestion recovery */ 625 CA_EVENT_FRTO, /* fast recovery timeout */ 626 CA_EVENT_LOSS, /* loss timeout */ 627 CA_EVENT_FAST_ACK, /* in sequence ack */ 628 CA_EVENT_SLOW_ACK, /* other ack */ 629 }; 630 631 /* 632 * Interface for adding new TCP congestion control handlers 633 */ 634 #define TCP_CA_NAME_MAX 16 635 #define TCP_CA_MAX 128 636 #define TCP_CA_BUF_MAX (TCP_CA_NAME_MAX*TCP_CA_MAX) 637 638 #define TCP_CONG_NON_RESTRICTED 0x1 639 #define TCP_CONG_RTT_STAMP 0x2 640 641 struct tcp_congestion_ops { 642 struct list_head list; 643 unsigned long flags; 644 645 /* initialize private data (optional) */ 646 void (*init)(struct sock *sk); 647 /* cleanup private data (optional) */ 648 void (*release)(struct sock *sk); 649 650 /* return slow start threshold (required) */ 651 u32 (*ssthresh)(struct sock *sk); 652 /* lower bound for congestion window (optional) */ 653 u32 (*min_cwnd)(const struct sock *sk); 654 /* do new cwnd calculation (required) */ 655 void (*cong_avoid)(struct sock *sk, u32 ack, 656 u32 rtt, u32 in_flight, int good_ack); 657 /* call before changing ca_state (optional) */ 658 void (*set_state)(struct sock *sk, u8 new_state); 659 /* call when cwnd event occurs (optional) */ 660 void (*cwnd_event)(struct sock *sk, enum tcp_ca_event ev); 661 /* new value of cwnd after loss (optional) */ 662 u32 (*undo_cwnd)(struct sock *sk); 663 /* hook for packet ack accounting (optional) */ 664 void (*pkts_acked)(struct sock *sk, u32 num_acked, ktime_t last); 665 /* get info for inet_diag (optional) */ 666 void (*get_info)(struct sock *sk, u32 ext, struct sk_buff *skb); 667 668 char name[TCP_CA_NAME_MAX]; 669 struct module *owner; 670 }; 671 672 extern int tcp_register_congestion_control(struct tcp_congestion_ops *type); 673 extern void tcp_unregister_congestion_control(struct tcp_congestion_ops *type); 674 675 extern void tcp_init_congestion_control(struct sock *sk); 676 extern void tcp_cleanup_congestion_control(struct sock *sk); 677 extern int tcp_set_default_congestion_control(const char *name); 678 extern void tcp_get_default_congestion_control(char *name); 679 extern void tcp_get_available_congestion_control(char *buf, size_t len); 680 extern void tcp_get_allowed_congestion_control(char *buf, size_t len); 681 extern int tcp_set_allowed_congestion_control(char *allowed); 682 extern int tcp_set_congestion_control(struct sock *sk, const char *name); 683 extern void tcp_slow_start(struct tcp_sock *tp); 684 685 extern struct tcp_congestion_ops tcp_init_congestion_ops; 686 extern u32 tcp_reno_ssthresh(struct sock *sk); 687 extern void tcp_reno_cong_avoid(struct sock *sk, u32 ack, 688 u32 rtt, u32 in_flight, int flag); 689 extern u32 tcp_reno_min_cwnd(const struct sock *sk); 690 extern struct tcp_congestion_ops tcp_reno; 691 692 static inline void tcp_set_ca_state(struct sock *sk, const u8 ca_state) 693 { 694 struct inet_connection_sock *icsk = inet_csk(sk); 695 696 if (icsk->icsk_ca_ops->set_state) 697 icsk->icsk_ca_ops->set_state(sk, ca_state); 698 icsk->icsk_ca_state = ca_state; 699 } 700 701 static inline void tcp_ca_event(struct sock *sk, const enum tcp_ca_event event) 702 { 703 const struct inet_connection_sock *icsk = inet_csk(sk); 704 705 if (icsk->icsk_ca_ops->cwnd_event) 706 icsk->icsk_ca_ops->cwnd_event(sk, event); 707 } 708 709 /* This determines how many packets are "in the network" to the best 710 * of our knowledge. In many cases it is conservative, but where 711 * detailed information is available from the receiver (via SACK 712 * blocks etc.) we can make more aggressive calculations. 713 * 714 * Use this for decisions involving congestion control, use just 715 * tp->packets_out to determine if the send queue is empty or not. 716 * 717 * Read this equation as: 718 * 719 * "Packets sent once on transmission queue" MINUS 720 * "Packets left network, but not honestly ACKed yet" PLUS 721 * "Packets fast retransmitted" 722 */ 723 static inline unsigned int tcp_packets_in_flight(const struct tcp_sock *tp) 724 { 725 return (tp->packets_out - tp->left_out + tp->retrans_out); 726 } 727 728 /* If cwnd > ssthresh, we may raise ssthresh to be half-way to cwnd. 729 * The exception is rate halving phase, when cwnd is decreasing towards 730 * ssthresh. 731 */ 732 static inline __u32 tcp_current_ssthresh(const struct sock *sk) 733 { 734 const struct tcp_sock *tp = tcp_sk(sk); 735 if ((1 << inet_csk(sk)->icsk_ca_state) & (TCPF_CA_CWR | TCPF_CA_Recovery)) 736 return tp->snd_ssthresh; 737 else 738 return max(tp->snd_ssthresh, 739 ((tp->snd_cwnd >> 1) + 740 (tp->snd_cwnd >> 2))); 741 } 742 743 static inline void tcp_sync_left_out(struct tcp_sock *tp) 744 { 745 BUG_ON(tp->rx_opt.sack_ok && 746 (tp->sacked_out + tp->lost_out > tp->packets_out)); 747 tp->left_out = tp->sacked_out + tp->lost_out; 748 } 749 750 extern void tcp_enter_cwr(struct sock *sk, const int set_ssthresh); 751 extern __u32 tcp_init_cwnd(struct tcp_sock *tp, struct dst_entry *dst); 752 753 /* Slow start with delack produces 3 packets of burst, so that 754 * it is safe "de facto". 755 */ 756 static __inline__ __u32 tcp_max_burst(const struct tcp_sock *tp) 757 { 758 return 3; 759 } 760 761 /* RFC2861 Check whether we are limited by application or congestion window 762 * This is the inverse of cwnd check in tcp_tso_should_defer 763 */ 764 static inline int tcp_is_cwnd_limited(const struct sock *sk, u32 in_flight) 765 { 766 const struct tcp_sock *tp = tcp_sk(sk); 767 u32 left; 768 769 if (in_flight >= tp->snd_cwnd) 770 return 1; 771 772 if (!sk_can_gso(sk)) 773 return 0; 774 775 left = tp->snd_cwnd - in_flight; 776 if (sysctl_tcp_tso_win_divisor) 777 return left * sysctl_tcp_tso_win_divisor < tp->snd_cwnd; 778 else 779 return left <= tcp_max_burst(tp); 780 } 781 782 static inline void tcp_minshall_update(struct tcp_sock *tp, int mss, 783 const struct sk_buff *skb) 784 { 785 if (skb->len < mss) 786 tp->snd_sml = TCP_SKB_CB(skb)->end_seq; 787 } 788 789 static inline void tcp_check_probe_timer(struct sock *sk) 790 { 791 struct tcp_sock *tp = tcp_sk(sk); 792 const struct inet_connection_sock *icsk = inet_csk(sk); 793 794 if (!tp->packets_out && !icsk->icsk_pending) 795 inet_csk_reset_xmit_timer(sk, ICSK_TIME_PROBE0, 796 icsk->icsk_rto, TCP_RTO_MAX); 797 } 798 799 static inline void tcp_push_pending_frames(struct sock *sk) 800 { 801 struct tcp_sock *tp = tcp_sk(sk); 802 803 __tcp_push_pending_frames(sk, tcp_current_mss(sk, 1), tp->nonagle); 804 } 805 806 static inline void tcp_init_wl(struct tcp_sock *tp, u32 ack, u32 seq) 807 { 808 tp->snd_wl1 = seq; 809 } 810 811 static inline void tcp_update_wl(struct tcp_sock *tp, u32 ack, u32 seq) 812 { 813 tp->snd_wl1 = seq; 814 } 815 816 /* 817 * Calculate(/check) TCP checksum 818 */ 819 static inline __sum16 tcp_v4_check(int len, __be32 saddr, 820 __be32 daddr, __wsum base) 821 { 822 return csum_tcpudp_magic(saddr,daddr,len,IPPROTO_TCP,base); 823 } 824 825 static inline __sum16 __tcp_checksum_complete(struct sk_buff *skb) 826 { 827 return __skb_checksum_complete(skb); 828 } 829 830 static inline int tcp_checksum_complete(struct sk_buff *skb) 831 { 832 return !skb_csum_unnecessary(skb) && 833 __tcp_checksum_complete(skb); 834 } 835 836 /* Prequeue for VJ style copy to user, combined with checksumming. */ 837 838 static inline void tcp_prequeue_init(struct tcp_sock *tp) 839 { 840 tp->ucopy.task = NULL; 841 tp->ucopy.len = 0; 842 tp->ucopy.memory = 0; 843 skb_queue_head_init(&tp->ucopy.prequeue); 844 #ifdef CONFIG_NET_DMA 845 tp->ucopy.dma_chan = NULL; 846 tp->ucopy.wakeup = 0; 847 tp->ucopy.pinned_list = NULL; 848 tp->ucopy.dma_cookie = 0; 849 #endif 850 } 851 852 /* Packet is added to VJ-style prequeue for processing in process 853 * context, if a reader task is waiting. Apparently, this exciting 854 * idea (VJ's mail "Re: query about TCP header on tcp-ip" of 07 Sep 93) 855 * failed somewhere. Latency? Burstiness? Well, at least now we will 856 * see, why it failed. 8)8) --ANK 857 * 858 * NOTE: is this not too big to inline? 859 */ 860 static inline int tcp_prequeue(struct sock *sk, struct sk_buff *skb) 861 { 862 struct tcp_sock *tp = tcp_sk(sk); 863 864 if (!sysctl_tcp_low_latency && tp->ucopy.task) { 865 __skb_queue_tail(&tp->ucopy.prequeue, skb); 866 tp->ucopy.memory += skb->truesize; 867 if (tp->ucopy.memory > sk->sk_rcvbuf) { 868 struct sk_buff *skb1; 869 870 BUG_ON(sock_owned_by_user(sk)); 871 872 while ((skb1 = __skb_dequeue(&tp->ucopy.prequeue)) != NULL) { 873 sk->sk_backlog_rcv(sk, skb1); 874 NET_INC_STATS_BH(LINUX_MIB_TCPPREQUEUEDROPPED); 875 } 876 877 tp->ucopy.memory = 0; 878 } else if (skb_queue_len(&tp->ucopy.prequeue) == 1) { 879 wake_up_interruptible(sk->sk_sleep); 880 if (!inet_csk_ack_scheduled(sk)) 881 inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK, 882 (3 * TCP_RTO_MIN) / 4, 883 TCP_RTO_MAX); 884 } 885 return 1; 886 } 887 return 0; 888 } 889 890 891 #undef STATE_TRACE 892 893 #ifdef STATE_TRACE 894 static const char *statename[]={ 895 "Unused","Established","Syn Sent","Syn Recv", 896 "Fin Wait 1","Fin Wait 2","Time Wait", "Close", 897 "Close Wait","Last ACK","Listen","Closing" 898 }; 899 #endif 900 901 static inline void tcp_set_state(struct sock *sk, int state) 902 { 903 int oldstate = sk->sk_state; 904 905 switch (state) { 906 case TCP_ESTABLISHED: 907 if (oldstate != TCP_ESTABLISHED) 908 TCP_INC_STATS(TCP_MIB_CURRESTAB); 909 break; 910 911 case TCP_CLOSE: 912 if (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED) 913 TCP_INC_STATS(TCP_MIB_ESTABRESETS); 914 915 sk->sk_prot->unhash(sk); 916 if (inet_csk(sk)->icsk_bind_hash && 917 !(sk->sk_userlocks & SOCK_BINDPORT_LOCK)) 918 inet_put_port(&tcp_hashinfo, sk); 919 /* fall through */ 920 default: 921 if (oldstate==TCP_ESTABLISHED) 922 TCP_DEC_STATS(TCP_MIB_CURRESTAB); 923 } 924 925 /* Change state AFTER socket is unhashed to avoid closed 926 * socket sitting in hash tables. 927 */ 928 sk->sk_state = state; 929 930 #ifdef STATE_TRACE 931 SOCK_DEBUG(sk, "TCP sk=%p, State %s -> %s\n",sk, statename[oldstate],statename[state]); 932 #endif 933 } 934 935 extern void tcp_done(struct sock *sk); 936 937 static inline void tcp_sack_reset(struct tcp_options_received *rx_opt) 938 { 939 rx_opt->dsack = 0; 940 rx_opt->eff_sacks = 0; 941 rx_opt->num_sacks = 0; 942 } 943 944 /* Determine a window scaling and initial window to offer. */ 945 extern void tcp_select_initial_window(int __space, __u32 mss, 946 __u32 *rcv_wnd, __u32 *window_clamp, 947 int wscale_ok, __u8 *rcv_wscale); 948 949 static inline int tcp_win_from_space(int space) 950 { 951 return sysctl_tcp_adv_win_scale<=0 ? 952 (space>>(-sysctl_tcp_adv_win_scale)) : 953 space - (space>>sysctl_tcp_adv_win_scale); 954 } 955 956 /* Note: caller must be prepared to deal with negative returns */ 957 static inline int tcp_space(const struct sock *sk) 958 { 959 return tcp_win_from_space(sk->sk_rcvbuf - 960 atomic_read(&sk->sk_rmem_alloc)); 961 } 962 963 static inline int tcp_full_space(const struct sock *sk) 964 { 965 return tcp_win_from_space(sk->sk_rcvbuf); 966 } 967 968 static inline void tcp_openreq_init(struct request_sock *req, 969 struct tcp_options_received *rx_opt, 970 struct sk_buff *skb) 971 { 972 struct inet_request_sock *ireq = inet_rsk(req); 973 974 req->rcv_wnd = 0; /* So that tcp_send_synack() knows! */ 975 tcp_rsk(req)->rcv_isn = TCP_SKB_CB(skb)->seq; 976 req->mss = rx_opt->mss_clamp; 977 req->ts_recent = rx_opt->saw_tstamp ? rx_opt->rcv_tsval : 0; 978 ireq->tstamp_ok = rx_opt->tstamp_ok; 979 ireq->sack_ok = rx_opt->sack_ok; 980 ireq->snd_wscale = rx_opt->snd_wscale; 981 ireq->wscale_ok = rx_opt->wscale_ok; 982 ireq->acked = 0; 983 ireq->ecn_ok = 0; 984 ireq->rmt_port = tcp_hdr(skb)->source; 985 } 986 987 extern void tcp_enter_memory_pressure(void); 988 989 static inline int keepalive_intvl_when(const struct tcp_sock *tp) 990 { 991 return tp->keepalive_intvl ? : sysctl_tcp_keepalive_intvl; 992 } 993 994 static inline int keepalive_time_when(const struct tcp_sock *tp) 995 { 996 return tp->keepalive_time ? : sysctl_tcp_keepalive_time; 997 } 998 999 static inline int tcp_fin_time(const struct sock *sk) 1000 { 1001 int fin_timeout = tcp_sk(sk)->linger2 ? : sysctl_tcp_fin_timeout; 1002 const int rto = inet_csk(sk)->icsk_rto; 1003 1004 if (fin_timeout < (rto << 2) - (rto >> 1)) 1005 fin_timeout = (rto << 2) - (rto >> 1); 1006 1007 return fin_timeout; 1008 } 1009 1010 static inline int tcp_paws_check(const struct tcp_options_received *rx_opt, int rst) 1011 { 1012 if ((s32)(rx_opt->rcv_tsval - rx_opt->ts_recent) >= 0) 1013 return 0; 1014 if (get_seconds() >= rx_opt->ts_recent_stamp + TCP_PAWS_24DAYS) 1015 return 0; 1016 1017 /* RST segments are not recommended to carry timestamp, 1018 and, if they do, it is recommended to ignore PAWS because 1019 "their cleanup function should take precedence over timestamps." 1020 Certainly, it is mistake. It is necessary to understand the reasons 1021 of this constraint to relax it: if peer reboots, clock may go 1022 out-of-sync and half-open connections will not be reset. 1023 Actually, the problem would be not existing if all 1024 the implementations followed draft about maintaining clock 1025 via reboots. Linux-2.2 DOES NOT! 1026 1027 However, we can relax time bounds for RST segments to MSL. 1028 */ 1029 if (rst && get_seconds() >= rx_opt->ts_recent_stamp + TCP_PAWS_MSL) 1030 return 0; 1031 return 1; 1032 } 1033 1034 #define TCP_CHECK_TIMER(sk) do { } while (0) 1035 1036 static inline void tcp_mib_init(void) 1037 { 1038 /* See RFC 2012 */ 1039 TCP_ADD_STATS_USER(TCP_MIB_RTOALGORITHM, 1); 1040 TCP_ADD_STATS_USER(TCP_MIB_RTOMIN, TCP_RTO_MIN*1000/HZ); 1041 TCP_ADD_STATS_USER(TCP_MIB_RTOMAX, TCP_RTO_MAX*1000/HZ); 1042 TCP_ADD_STATS_USER(TCP_MIB_MAXCONN, -1); 1043 } 1044 1045 /*from STCP */ 1046 static inline void clear_all_retrans_hints(struct tcp_sock *tp){ 1047 tp->lost_skb_hint = NULL; 1048 tp->scoreboard_skb_hint = NULL; 1049 tp->retransmit_skb_hint = NULL; 1050 tp->forward_skb_hint = NULL; 1051 tp->fastpath_skb_hint = NULL; 1052 } 1053 1054 /* MD5 Signature */ 1055 struct crypto_hash; 1056 1057 /* - key database */ 1058 struct tcp_md5sig_key { 1059 u8 *key; 1060 u8 keylen; 1061 }; 1062 1063 struct tcp4_md5sig_key { 1064 u8 *key; 1065 u16 keylen; 1066 __be32 addr; 1067 }; 1068 1069 struct tcp6_md5sig_key { 1070 u8 *key; 1071 u16 keylen; 1072 #if 0 1073 u32 scope_id; /* XXX */ 1074 #endif 1075 struct in6_addr addr; 1076 }; 1077 1078 /* - sock block */ 1079 struct tcp_md5sig_info { 1080 struct tcp4_md5sig_key *keys4; 1081 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) 1082 struct tcp6_md5sig_key *keys6; 1083 u32 entries6; 1084 u32 alloced6; 1085 #endif 1086 u32 entries4; 1087 u32 alloced4; 1088 }; 1089 1090 /* - pseudo header */ 1091 struct tcp4_pseudohdr { 1092 __be32 saddr; 1093 __be32 daddr; 1094 __u8 pad; 1095 __u8 protocol; 1096 __be16 len; 1097 }; 1098 1099 struct tcp6_pseudohdr { 1100 struct in6_addr saddr; 1101 struct in6_addr daddr; 1102 __be32 len; 1103 __be32 protocol; /* including padding */ 1104 }; 1105 1106 union tcp_md5sum_block { 1107 struct tcp4_pseudohdr ip4; 1108 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) 1109 struct tcp6_pseudohdr ip6; 1110 #endif 1111 }; 1112 1113 /* - pool: digest algorithm, hash description and scratch buffer */ 1114 struct tcp_md5sig_pool { 1115 struct hash_desc md5_desc; 1116 union tcp_md5sum_block md5_blk; 1117 }; 1118 1119 #define TCP_MD5SIG_MAXKEYS (~(u32)0) /* really?! */ 1120 1121 /* - functions */ 1122 extern int tcp_v4_calc_md5_hash(char *md5_hash, 1123 struct tcp_md5sig_key *key, 1124 struct sock *sk, 1125 struct dst_entry *dst, 1126 struct request_sock *req, 1127 struct tcphdr *th, 1128 int protocol, int tcplen); 1129 extern struct tcp_md5sig_key *tcp_v4_md5_lookup(struct sock *sk, 1130 struct sock *addr_sk); 1131 1132 extern int tcp_v4_md5_do_add(struct sock *sk, 1133 __be32 addr, 1134 u8 *newkey, 1135 u8 newkeylen); 1136 1137 extern int tcp_v4_md5_do_del(struct sock *sk, 1138 __be32 addr); 1139 1140 extern struct tcp_md5sig_pool **tcp_alloc_md5sig_pool(void); 1141 extern void tcp_free_md5sig_pool(void); 1142 1143 extern struct tcp_md5sig_pool *__tcp_get_md5sig_pool(int cpu); 1144 extern void __tcp_put_md5sig_pool(void); 1145 1146 static inline 1147 struct tcp_md5sig_pool *tcp_get_md5sig_pool(void) 1148 { 1149 int cpu = get_cpu(); 1150 struct tcp_md5sig_pool *ret = __tcp_get_md5sig_pool(cpu); 1151 if (!ret) 1152 put_cpu(); 1153 return ret; 1154 } 1155 1156 static inline void tcp_put_md5sig_pool(void) 1157 { 1158 __tcp_put_md5sig_pool(); 1159 put_cpu(); 1160 } 1161 1162 /* write queue abstraction */ 1163 static inline void tcp_write_queue_purge(struct sock *sk) 1164 { 1165 struct sk_buff *skb; 1166 1167 while ((skb = __skb_dequeue(&sk->sk_write_queue)) != NULL) 1168 sk_stream_free_skb(sk, skb); 1169 sk_stream_mem_reclaim(sk); 1170 } 1171 1172 static inline struct sk_buff *tcp_write_queue_head(struct sock *sk) 1173 { 1174 struct sk_buff *skb = sk->sk_write_queue.next; 1175 if (skb == (struct sk_buff *) &sk->sk_write_queue) 1176 return NULL; 1177 return skb; 1178 } 1179 1180 static inline struct sk_buff *tcp_write_queue_tail(struct sock *sk) 1181 { 1182 struct sk_buff *skb = sk->sk_write_queue.prev; 1183 if (skb == (struct sk_buff *) &sk->sk_write_queue) 1184 return NULL; 1185 return skb; 1186 } 1187 1188 static inline struct sk_buff *tcp_write_queue_next(struct sock *sk, struct sk_buff *skb) 1189 { 1190 return skb->next; 1191 } 1192 1193 #define tcp_for_write_queue(skb, sk) \ 1194 for (skb = (sk)->sk_write_queue.next; \ 1195 (skb != (struct sk_buff *)&(sk)->sk_write_queue); \ 1196 skb = skb->next) 1197 1198 #define tcp_for_write_queue_from(skb, sk) \ 1199 for (; (skb != (struct sk_buff *)&(sk)->sk_write_queue);\ 1200 skb = skb->next) 1201 1202 static inline struct sk_buff *tcp_send_head(struct sock *sk) 1203 { 1204 return sk->sk_send_head; 1205 } 1206 1207 static inline void tcp_advance_send_head(struct sock *sk, struct sk_buff *skb) 1208 { 1209 struct tcp_sock *tp = tcp_sk(sk); 1210 1211 sk->sk_send_head = skb->next; 1212 if (sk->sk_send_head == (struct sk_buff *)&sk->sk_write_queue) 1213 sk->sk_send_head = NULL; 1214 /* Don't override Nagle indefinately with F-RTO */ 1215 if (tp->frto_counter == 2) 1216 tp->frto_counter = 3; 1217 } 1218 1219 static inline void tcp_check_send_head(struct sock *sk, struct sk_buff *skb_unlinked) 1220 { 1221 if (sk->sk_send_head == skb_unlinked) 1222 sk->sk_send_head = NULL; 1223 } 1224 1225 static inline void tcp_init_send_head(struct sock *sk) 1226 { 1227 sk->sk_send_head = NULL; 1228 } 1229 1230 static inline void __tcp_add_write_queue_tail(struct sock *sk, struct sk_buff *skb) 1231 { 1232 __skb_queue_tail(&sk->sk_write_queue, skb); 1233 } 1234 1235 static inline void tcp_add_write_queue_tail(struct sock *sk, struct sk_buff *skb) 1236 { 1237 __tcp_add_write_queue_tail(sk, skb); 1238 1239 /* Queue it, remembering where we must start sending. */ 1240 if (sk->sk_send_head == NULL) 1241 sk->sk_send_head = skb; 1242 } 1243 1244 static inline void __tcp_add_write_queue_head(struct sock *sk, struct sk_buff *skb) 1245 { 1246 __skb_queue_head(&sk->sk_write_queue, skb); 1247 } 1248 1249 /* Insert buff after skb on the write queue of sk. */ 1250 static inline void tcp_insert_write_queue_after(struct sk_buff *skb, 1251 struct sk_buff *buff, 1252 struct sock *sk) 1253 { 1254 __skb_append(skb, buff, &sk->sk_write_queue); 1255 } 1256 1257 /* Insert skb between prev and next on the write queue of sk. */ 1258 static inline void tcp_insert_write_queue_before(struct sk_buff *new, 1259 struct sk_buff *skb, 1260 struct sock *sk) 1261 { 1262 __skb_insert(new, skb->prev, skb, &sk->sk_write_queue); 1263 } 1264 1265 static inline void tcp_unlink_write_queue(struct sk_buff *skb, struct sock *sk) 1266 { 1267 __skb_unlink(skb, &sk->sk_write_queue); 1268 } 1269 1270 static inline int tcp_skb_is_last(const struct sock *sk, 1271 const struct sk_buff *skb) 1272 { 1273 return skb->next == (struct sk_buff *)&sk->sk_write_queue; 1274 } 1275 1276 static inline int tcp_write_queue_empty(struct sock *sk) 1277 { 1278 return skb_queue_empty(&sk->sk_write_queue); 1279 } 1280 1281 /* /proc */ 1282 enum tcp_seq_states { 1283 TCP_SEQ_STATE_LISTENING, 1284 TCP_SEQ_STATE_OPENREQ, 1285 TCP_SEQ_STATE_ESTABLISHED, 1286 TCP_SEQ_STATE_TIME_WAIT, 1287 }; 1288 1289 struct tcp_seq_afinfo { 1290 struct module *owner; 1291 char *name; 1292 sa_family_t family; 1293 int (*seq_show) (struct seq_file *m, void *v); 1294 struct file_operations *seq_fops; 1295 }; 1296 1297 struct tcp_iter_state { 1298 sa_family_t family; 1299 enum tcp_seq_states state; 1300 struct sock *syn_wait_sk; 1301 int bucket, sbucket, num, uid; 1302 struct seq_operations seq_ops; 1303 }; 1304 1305 extern int tcp_proc_register(struct tcp_seq_afinfo *afinfo); 1306 extern void tcp_proc_unregister(struct tcp_seq_afinfo *afinfo); 1307 1308 extern struct request_sock_ops tcp_request_sock_ops; 1309 1310 extern int tcp_v4_destroy_sock(struct sock *sk); 1311 1312 extern int tcp_v4_gso_send_check(struct sk_buff *skb); 1313 extern struct sk_buff *tcp_tso_segment(struct sk_buff *skb, int features); 1314 1315 #ifdef CONFIG_PROC_FS 1316 extern int tcp4_proc_init(void); 1317 extern void tcp4_proc_exit(void); 1318 #endif 1319 1320 /* TCP af-specific functions */ 1321 struct tcp_sock_af_ops { 1322 #ifdef CONFIG_TCP_MD5SIG 1323 struct tcp_md5sig_key *(*md5_lookup) (struct sock *sk, 1324 struct sock *addr_sk); 1325 int (*calc_md5_hash) (char *location, 1326 struct tcp_md5sig_key *md5, 1327 struct sock *sk, 1328 struct dst_entry *dst, 1329 struct request_sock *req, 1330 struct tcphdr *th, 1331 int protocol, int len); 1332 int (*md5_add) (struct sock *sk, 1333 struct sock *addr_sk, 1334 u8 *newkey, 1335 u8 len); 1336 int (*md5_parse) (struct sock *sk, 1337 char __user *optval, 1338 int optlen); 1339 #endif 1340 }; 1341 1342 struct tcp_request_sock_ops { 1343 #ifdef CONFIG_TCP_MD5SIG 1344 struct tcp_md5sig_key *(*md5_lookup) (struct sock *sk, 1345 struct request_sock *req); 1346 #endif 1347 }; 1348 1349 extern void tcp_v4_init(struct net_proto_family *ops); 1350 extern void tcp_init(void); 1351 1352 #endif /* _TCP_H */ 1353