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 #include <linux/cryptohash.h> 33 34 #include <net/inet_connection_sock.h> 35 #include <net/inet_timewait_sock.h> 36 #include <net/inet_hashtables.h> 37 #include <net/checksum.h> 38 #include <net/request_sock.h> 39 #include <net/sock.h> 40 #include <net/snmp.h> 41 #include <net/ip.h> 42 #include <net/tcp_states.h> 43 #include <net/inet_ecn.h> 44 #include <net/dst.h> 45 46 #include <linux/seq_file.h> 47 48 extern struct inet_hashinfo tcp_hashinfo; 49 50 extern struct percpu_counter tcp_orphan_count; 51 extern void tcp_time_wait(struct sock *sk, int state, int timeo); 52 53 #define MAX_TCP_HEADER (128 + MAX_HEADER) 54 #define MAX_TCP_OPTION_SPACE 40 55 56 /* 57 * Never offer a window over 32767 without using window scaling. Some 58 * poor stacks do signed 16bit maths! 59 */ 60 #define MAX_TCP_WINDOW 32767U 61 62 /* Minimal accepted MSS. It is (60+60+8) - (20+20). */ 63 #define TCP_MIN_MSS 88U 64 65 /* Minimal RCV_MSS. */ 66 #define TCP_MIN_RCVMSS 536U 67 68 /* The least MTU to use for probing */ 69 #define TCP_BASE_MSS 512 70 71 /* After receiving this amount of duplicate ACKs fast retransmit starts. */ 72 #define TCP_FASTRETRANS_THRESH 3 73 74 /* Maximal reordering. */ 75 #define TCP_MAX_REORDERING 127 76 77 /* Maximal number of ACKs sent quickly to accelerate slow-start. */ 78 #define TCP_MAX_QUICKACKS 16U 79 80 /* urg_data states */ 81 #define TCP_URG_VALID 0x0100 82 #define TCP_URG_NOTYET 0x0200 83 #define TCP_URG_READ 0x0400 84 85 #define TCP_RETR1 3 /* 86 * This is how many retries it does before it 87 * tries to figure out if the gateway is 88 * down. Minimal RFC value is 3; it corresponds 89 * to ~3sec-8min depending on RTO. 90 */ 91 92 #define TCP_RETR2 15 /* 93 * This should take at least 94 * 90 minutes to time out. 95 * RFC1122 says that the limit is 100 sec. 96 * 15 is ~13-30min depending on RTO. 97 */ 98 99 #define TCP_SYN_RETRIES 5 /* number of times to retry active opening a 100 * connection: ~180sec is RFC minimum */ 101 102 #define TCP_SYNACK_RETRIES 5 /* number of times to retry passive opening a 103 * connection: ~180sec is RFC minimum */ 104 105 106 #define TCP_ORPHAN_RETRIES 7 /* number of times to retry on an orphaned 107 * socket. 7 is ~50sec-16min. 108 */ 109 110 111 #define TCP_TIMEWAIT_LEN (60*HZ) /* how long to wait to destroy TIME-WAIT 112 * state, about 60 seconds */ 113 #define TCP_FIN_TIMEOUT TCP_TIMEWAIT_LEN 114 /* BSD style FIN_WAIT2 deadlock breaker. 115 * It used to be 3min, new value is 60sec, 116 * to combine FIN-WAIT-2 timeout with 117 * TIME-WAIT timer. 118 */ 119 120 #define TCP_DELACK_MAX ((unsigned)(HZ/5)) /* maximal time to delay before sending an ACK */ 121 #if HZ >= 100 122 #define TCP_DELACK_MIN ((unsigned)(HZ/25)) /* minimal time to delay before sending an ACK */ 123 #define TCP_ATO_MIN ((unsigned)(HZ/25)) 124 #else 125 #define TCP_DELACK_MIN 4U 126 #define TCP_ATO_MIN 4U 127 #endif 128 #define TCP_RTO_MAX ((unsigned)(120*HZ)) 129 #define TCP_RTO_MIN ((unsigned)(HZ/5)) 130 #define TCP_TIMEOUT_INIT ((unsigned)(3*HZ)) /* RFC 1122 initial RTO value */ 131 132 #define TCP_RESOURCE_PROBE_INTERVAL ((unsigned)(HZ/2U)) /* Maximal interval between probes 133 * for local resources. 134 */ 135 136 #define TCP_KEEPALIVE_TIME (120*60*HZ) /* two hours */ 137 #define TCP_KEEPALIVE_PROBES 9 /* Max of 9 keepalive probes */ 138 #define TCP_KEEPALIVE_INTVL (75*HZ) 139 140 #define MAX_TCP_KEEPIDLE 32767 141 #define MAX_TCP_KEEPINTVL 32767 142 #define MAX_TCP_KEEPCNT 127 143 #define MAX_TCP_SYNCNT 127 144 145 #define TCP_SYNQ_INTERVAL (HZ/5) /* Period of SYNACK timer */ 146 147 #define TCP_PAWS_24DAYS (60 * 60 * 24 * 24) 148 #define TCP_PAWS_MSL 60 /* Per-host timestamps are invalidated 149 * after this time. It should be equal 150 * (or greater than) TCP_TIMEWAIT_LEN 151 * to provide reliability equal to one 152 * provided by timewait state. 153 */ 154 #define TCP_PAWS_WINDOW 1 /* Replay window for per-host 155 * timestamps. It must be less than 156 * minimal timewait lifetime. 157 */ 158 /* 159 * TCP option 160 */ 161 162 #define TCPOPT_NOP 1 /* Padding */ 163 #define TCPOPT_EOL 0 /* End of options */ 164 #define TCPOPT_MSS 2 /* Segment size negotiating */ 165 #define TCPOPT_WINDOW 3 /* Window scaling */ 166 #define TCPOPT_SACK_PERM 4 /* SACK Permitted */ 167 #define TCPOPT_SACK 5 /* SACK Block */ 168 #define TCPOPT_TIMESTAMP 8 /* Better RTT estimations/PAWS */ 169 #define TCPOPT_MD5SIG 19 /* MD5 Signature (RFC2385) */ 170 171 /* 172 * TCP option lengths 173 */ 174 175 #define TCPOLEN_MSS 4 176 #define TCPOLEN_WINDOW 3 177 #define TCPOLEN_SACK_PERM 2 178 #define TCPOLEN_TIMESTAMP 10 179 #define TCPOLEN_MD5SIG 18 180 181 /* But this is what stacks really send out. */ 182 #define TCPOLEN_TSTAMP_ALIGNED 12 183 #define TCPOLEN_WSCALE_ALIGNED 4 184 #define TCPOLEN_SACKPERM_ALIGNED 4 185 #define TCPOLEN_SACK_BASE 2 186 #define TCPOLEN_SACK_BASE_ALIGNED 4 187 #define TCPOLEN_SACK_PERBLOCK 8 188 #define TCPOLEN_MD5SIG_ALIGNED 20 189 #define TCPOLEN_MSS_ALIGNED 4 190 191 /* Flags in tp->nonagle */ 192 #define TCP_NAGLE_OFF 1 /* Nagle's algo is disabled */ 193 #define TCP_NAGLE_CORK 2 /* Socket is corked */ 194 #define TCP_NAGLE_PUSH 4 /* Cork is overridden for already queued data */ 195 196 extern struct inet_timewait_death_row tcp_death_row; 197 198 /* sysctl variables for tcp */ 199 extern int sysctl_tcp_timestamps; 200 extern int sysctl_tcp_window_scaling; 201 extern int sysctl_tcp_sack; 202 extern int sysctl_tcp_fin_timeout; 203 extern int sysctl_tcp_keepalive_time; 204 extern int sysctl_tcp_keepalive_probes; 205 extern int sysctl_tcp_keepalive_intvl; 206 extern int sysctl_tcp_syn_retries; 207 extern int sysctl_tcp_synack_retries; 208 extern int sysctl_tcp_retries1; 209 extern int sysctl_tcp_retries2; 210 extern int sysctl_tcp_orphan_retries; 211 extern int sysctl_tcp_syncookies; 212 extern int sysctl_tcp_retrans_collapse; 213 extern int sysctl_tcp_stdurg; 214 extern int sysctl_tcp_rfc1337; 215 extern int sysctl_tcp_abort_on_overflow; 216 extern int sysctl_tcp_max_orphans; 217 extern int sysctl_tcp_fack; 218 extern int sysctl_tcp_reordering; 219 extern int sysctl_tcp_ecn; 220 extern int sysctl_tcp_dsack; 221 extern int sysctl_tcp_mem[3]; 222 extern int sysctl_tcp_wmem[3]; 223 extern int sysctl_tcp_rmem[3]; 224 extern int sysctl_tcp_app_win; 225 extern int sysctl_tcp_adv_win_scale; 226 extern int sysctl_tcp_tw_reuse; 227 extern int sysctl_tcp_frto; 228 extern int sysctl_tcp_frto_response; 229 extern int sysctl_tcp_low_latency; 230 extern int sysctl_tcp_dma_copybreak; 231 extern int sysctl_tcp_nometrics_save; 232 extern int sysctl_tcp_moderate_rcvbuf; 233 extern int sysctl_tcp_tso_win_divisor; 234 extern int sysctl_tcp_abc; 235 extern int sysctl_tcp_mtu_probing; 236 extern int sysctl_tcp_base_mss; 237 extern int sysctl_tcp_workaround_signed_windows; 238 extern int sysctl_tcp_slow_start_after_idle; 239 extern int sysctl_tcp_max_ssthresh; 240 241 extern atomic_t tcp_memory_allocated; 242 extern struct percpu_counter tcp_sockets_allocated; 243 extern int tcp_memory_pressure; 244 245 /* 246 * The next routines deal with comparing 32 bit unsigned ints 247 * and worry about wraparound (automatic with unsigned arithmetic). 248 */ 249 250 static inline int before(__u32 seq1, __u32 seq2) 251 { 252 return (__s32)(seq1-seq2) < 0; 253 } 254 #define after(seq2, seq1) before(seq1, seq2) 255 256 /* is s2<=s1<=s3 ? */ 257 static inline int between(__u32 seq1, __u32 seq2, __u32 seq3) 258 { 259 return seq3 - seq2 >= seq1 - seq2; 260 } 261 262 static inline int tcp_too_many_orphans(struct sock *sk, int num) 263 { 264 return (num > sysctl_tcp_max_orphans) || 265 (sk->sk_wmem_queued > SOCK_MIN_SNDBUF && 266 atomic_read(&tcp_memory_allocated) > sysctl_tcp_mem[2]); 267 } 268 269 /* syncookies: remember time of last synqueue overflow */ 270 static inline void tcp_synq_overflow(struct sock *sk) 271 { 272 tcp_sk(sk)->rx_opt.ts_recent_stamp = jiffies; 273 } 274 275 /* syncookies: no recent synqueue overflow on this listening socket? */ 276 static inline int tcp_synq_no_recent_overflow(const struct sock *sk) 277 { 278 unsigned long last_overflow = tcp_sk(sk)->rx_opt.ts_recent_stamp; 279 return time_after(jiffies, last_overflow + TCP_TIMEOUT_INIT); 280 } 281 282 extern struct proto tcp_prot; 283 284 #define TCP_INC_STATS(net, field) SNMP_INC_STATS((net)->mib.tcp_statistics, field) 285 #define TCP_INC_STATS_BH(net, field) SNMP_INC_STATS_BH((net)->mib.tcp_statistics, field) 286 #define TCP_DEC_STATS(net, field) SNMP_DEC_STATS((net)->mib.tcp_statistics, field) 287 #define TCP_ADD_STATS_USER(net, field, val) SNMP_ADD_STATS_USER((net)->mib.tcp_statistics, field, val) 288 289 extern void tcp_v4_err(struct sk_buff *skb, u32); 290 291 extern void tcp_shutdown (struct sock *sk, int how); 292 293 extern int tcp_v4_rcv(struct sk_buff *skb); 294 295 extern int tcp_v4_remember_stamp(struct sock *sk); 296 297 extern int tcp_v4_tw_remember_stamp(struct inet_timewait_sock *tw); 298 299 extern int tcp_sendmsg(struct kiocb *iocb, struct socket *sock, 300 struct msghdr *msg, size_t size); 301 extern ssize_t tcp_sendpage(struct socket *sock, struct page *page, int offset, size_t size, int flags); 302 303 extern int tcp_ioctl(struct sock *sk, 304 int cmd, 305 unsigned long arg); 306 307 extern int tcp_rcv_state_process(struct sock *sk, 308 struct sk_buff *skb, 309 struct tcphdr *th, 310 unsigned len); 311 312 extern int tcp_rcv_established(struct sock *sk, 313 struct sk_buff *skb, 314 struct tcphdr *th, 315 unsigned len); 316 317 extern void tcp_rcv_space_adjust(struct sock *sk); 318 319 extern void tcp_cleanup_rbuf(struct sock *sk, int copied); 320 321 extern int tcp_twsk_unique(struct sock *sk, 322 struct sock *sktw, void *twp); 323 324 extern void tcp_twsk_destructor(struct sock *sk); 325 326 extern ssize_t tcp_splice_read(struct socket *sk, loff_t *ppos, 327 struct pipe_inode_info *pipe, size_t len, unsigned int flags); 328 329 static inline void tcp_dec_quickack_mode(struct sock *sk, 330 const unsigned int pkts) 331 { 332 struct inet_connection_sock *icsk = inet_csk(sk); 333 334 if (icsk->icsk_ack.quick) { 335 if (pkts >= icsk->icsk_ack.quick) { 336 icsk->icsk_ack.quick = 0; 337 /* Leaving quickack mode we deflate ATO. */ 338 icsk->icsk_ack.ato = TCP_ATO_MIN; 339 } else 340 icsk->icsk_ack.quick -= pkts; 341 } 342 } 343 344 extern void tcp_enter_quickack_mode(struct sock *sk); 345 346 static inline void tcp_clear_options(struct tcp_options_received *rx_opt) 347 { 348 rx_opt->tstamp_ok = rx_opt->sack_ok = rx_opt->wscale_ok = rx_opt->snd_wscale = 0; 349 } 350 351 #define TCP_ECN_OK 1 352 #define TCP_ECN_QUEUE_CWR 2 353 #define TCP_ECN_DEMAND_CWR 4 354 355 static __inline__ void 356 TCP_ECN_create_request(struct request_sock *req, struct tcphdr *th) 357 { 358 if (sysctl_tcp_ecn && th->ece && th->cwr) 359 inet_rsk(req)->ecn_ok = 1; 360 } 361 362 enum tcp_tw_status 363 { 364 TCP_TW_SUCCESS = 0, 365 TCP_TW_RST = 1, 366 TCP_TW_ACK = 2, 367 TCP_TW_SYN = 3 368 }; 369 370 371 extern enum tcp_tw_status tcp_timewait_state_process(struct inet_timewait_sock *tw, 372 struct sk_buff *skb, 373 const struct tcphdr *th); 374 375 extern struct sock * tcp_check_req(struct sock *sk,struct sk_buff *skb, 376 struct request_sock *req, 377 struct request_sock **prev); 378 extern int tcp_child_process(struct sock *parent, 379 struct sock *child, 380 struct sk_buff *skb); 381 extern int tcp_use_frto(struct sock *sk); 382 extern void tcp_enter_frto(struct sock *sk); 383 extern void tcp_enter_loss(struct sock *sk, int how); 384 extern void tcp_clear_retrans(struct tcp_sock *tp); 385 extern void tcp_update_metrics(struct sock *sk); 386 387 extern void tcp_close(struct sock *sk, 388 long timeout); 389 extern unsigned int tcp_poll(struct file * file, struct socket *sock, struct poll_table_struct *wait); 390 391 extern int tcp_getsockopt(struct sock *sk, int level, 392 int optname, 393 char __user *optval, 394 int __user *optlen); 395 extern int tcp_setsockopt(struct sock *sk, int level, 396 int optname, char __user *optval, 397 int optlen); 398 extern int compat_tcp_getsockopt(struct sock *sk, 399 int level, int optname, 400 char __user *optval, int __user *optlen); 401 extern int compat_tcp_setsockopt(struct sock *sk, 402 int level, int optname, 403 char __user *optval, int optlen); 404 extern void tcp_set_keepalive(struct sock *sk, int val); 405 extern int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, 406 struct msghdr *msg, 407 size_t len, int nonblock, 408 int flags, int *addr_len); 409 410 extern void tcp_parse_options(struct sk_buff *skb, 411 struct tcp_options_received *opt_rx, 412 int estab); 413 414 extern u8 *tcp_parse_md5sig_option(struct tcphdr *th); 415 416 /* 417 * TCP v4 functions exported for the inet6 API 418 */ 419 420 extern void tcp_v4_send_check(struct sock *sk, int len, 421 struct sk_buff *skb); 422 423 extern int tcp_v4_conn_request(struct sock *sk, 424 struct sk_buff *skb); 425 426 extern struct sock * tcp_create_openreq_child(struct sock *sk, 427 struct request_sock *req, 428 struct sk_buff *skb); 429 430 extern struct sock * tcp_v4_syn_recv_sock(struct sock *sk, 431 struct sk_buff *skb, 432 struct request_sock *req, 433 struct dst_entry *dst); 434 435 extern int tcp_v4_do_rcv(struct sock *sk, 436 struct sk_buff *skb); 437 438 extern int tcp_v4_connect(struct sock *sk, 439 struct sockaddr *uaddr, 440 int addr_len); 441 442 extern int tcp_connect(struct sock *sk); 443 444 extern struct sk_buff * tcp_make_synack(struct sock *sk, 445 struct dst_entry *dst, 446 struct request_sock *req); 447 448 extern int tcp_disconnect(struct sock *sk, int flags); 449 450 451 /* From syncookies.c */ 452 extern __u32 syncookie_secret[2][16-4+SHA_DIGEST_WORDS]; 453 extern struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb, 454 struct ip_options *opt); 455 extern __u32 cookie_v4_init_sequence(struct sock *sk, struct sk_buff *skb, 456 __u16 *mss); 457 458 extern __u32 cookie_init_timestamp(struct request_sock *req); 459 extern void cookie_check_timestamp(struct tcp_options_received *tcp_opt); 460 461 /* From net/ipv6/syncookies.c */ 462 extern struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb); 463 extern __u32 cookie_v6_init_sequence(struct sock *sk, struct sk_buff *skb, 464 __u16 *mss); 465 466 /* tcp_output.c */ 467 468 extern void __tcp_push_pending_frames(struct sock *sk, unsigned int cur_mss, 469 int nonagle); 470 extern int tcp_may_send_now(struct sock *sk); 471 extern int tcp_retransmit_skb(struct sock *, struct sk_buff *); 472 extern void tcp_retransmit_timer(struct sock *sk); 473 extern void tcp_xmit_retransmit_queue(struct sock *); 474 extern void tcp_simple_retransmit(struct sock *); 475 extern int tcp_trim_head(struct sock *, struct sk_buff *, u32); 476 extern int tcp_fragment(struct sock *, struct sk_buff *, u32, unsigned int); 477 478 extern void tcp_send_probe0(struct sock *); 479 extern void tcp_send_partial(struct sock *); 480 extern int tcp_write_wakeup(struct sock *); 481 extern void tcp_send_fin(struct sock *sk); 482 extern void tcp_send_active_reset(struct sock *sk, gfp_t priority); 483 extern int tcp_send_synack(struct sock *); 484 extern void tcp_push_one(struct sock *, unsigned int mss_now); 485 extern void tcp_send_ack(struct sock *sk); 486 extern void tcp_send_delayed_ack(struct sock *sk); 487 488 /* tcp_input.c */ 489 extern void tcp_cwnd_application_limited(struct sock *sk); 490 491 /* tcp_timer.c */ 492 extern void tcp_init_xmit_timers(struct sock *); 493 static inline void tcp_clear_xmit_timers(struct sock *sk) 494 { 495 inet_csk_clear_xmit_timers(sk); 496 } 497 498 extern unsigned int tcp_sync_mss(struct sock *sk, u32 pmtu); 499 extern unsigned int tcp_current_mss(struct sock *sk); 500 501 /* Bound MSS / TSO packet size with the half of the window */ 502 static inline int tcp_bound_to_half_wnd(struct tcp_sock *tp, int pktsize) 503 { 504 if (tp->max_window && pktsize > (tp->max_window >> 1)) 505 return max(tp->max_window >> 1, 68U - tp->tcp_header_len); 506 else 507 return pktsize; 508 } 509 510 /* tcp.c */ 511 extern void tcp_get_info(struct sock *, struct tcp_info *); 512 513 /* Read 'sendfile()'-style from a TCP socket */ 514 typedef int (*sk_read_actor_t)(read_descriptor_t *, struct sk_buff *, 515 unsigned int, size_t); 516 extern int tcp_read_sock(struct sock *sk, read_descriptor_t *desc, 517 sk_read_actor_t recv_actor); 518 519 extern void tcp_initialize_rcv_mss(struct sock *sk); 520 521 extern int tcp_mtu_to_mss(struct sock *sk, int pmtu); 522 extern int tcp_mss_to_mtu(struct sock *sk, int mss); 523 extern void tcp_mtup_init(struct sock *sk); 524 525 static inline void tcp_bound_rto(const struct sock *sk) 526 { 527 if (inet_csk(sk)->icsk_rto > TCP_RTO_MAX) 528 inet_csk(sk)->icsk_rto = TCP_RTO_MAX; 529 } 530 531 static inline u32 __tcp_set_rto(const struct tcp_sock *tp) 532 { 533 return (tp->srtt >> 3) + tp->rttvar; 534 } 535 536 static inline void __tcp_fast_path_on(struct tcp_sock *tp, u32 snd_wnd) 537 { 538 tp->pred_flags = htonl((tp->tcp_header_len << 26) | 539 ntohl(TCP_FLAG_ACK) | 540 snd_wnd); 541 } 542 543 static inline void tcp_fast_path_on(struct tcp_sock *tp) 544 { 545 __tcp_fast_path_on(tp, tp->snd_wnd >> tp->rx_opt.snd_wscale); 546 } 547 548 static inline void tcp_fast_path_check(struct sock *sk) 549 { 550 struct tcp_sock *tp = tcp_sk(sk); 551 552 if (skb_queue_empty(&tp->out_of_order_queue) && 553 tp->rcv_wnd && 554 atomic_read(&sk->sk_rmem_alloc) < sk->sk_rcvbuf && 555 !tp->urg_data) 556 tcp_fast_path_on(tp); 557 } 558 559 /* Compute the actual rto_min value */ 560 static inline u32 tcp_rto_min(struct sock *sk) 561 { 562 struct dst_entry *dst = __sk_dst_get(sk); 563 u32 rto_min = TCP_RTO_MIN; 564 565 if (dst && dst_metric_locked(dst, RTAX_RTO_MIN)) 566 rto_min = dst_metric_rtt(dst, RTAX_RTO_MIN); 567 return rto_min; 568 } 569 570 /* Compute the actual receive window we are currently advertising. 571 * Rcv_nxt can be after the window if our peer push more data 572 * than the offered window. 573 */ 574 static inline u32 tcp_receive_window(const struct tcp_sock *tp) 575 { 576 s32 win = tp->rcv_wup + tp->rcv_wnd - tp->rcv_nxt; 577 578 if (win < 0) 579 win = 0; 580 return (u32) win; 581 } 582 583 /* Choose a new window, without checks for shrinking, and without 584 * scaling applied to the result. The caller does these things 585 * if necessary. This is a "raw" window selection. 586 */ 587 extern u32 __tcp_select_window(struct sock *sk); 588 589 /* TCP timestamps are only 32-bits, this causes a slight 590 * complication on 64-bit systems since we store a snapshot 591 * of jiffies in the buffer control blocks below. We decided 592 * to use only the low 32-bits of jiffies and hide the ugly 593 * casts with the following macro. 594 */ 595 #define tcp_time_stamp ((__u32)(jiffies)) 596 597 /* This is what the send packet queuing engine uses to pass 598 * TCP per-packet control information to the transmission 599 * code. We also store the host-order sequence numbers in 600 * here too. This is 36 bytes on 32-bit architectures, 601 * 40 bytes on 64-bit machines, if this grows please adjust 602 * skbuff.h:skbuff->cb[xxx] size appropriately. 603 */ 604 struct tcp_skb_cb { 605 union { 606 struct inet_skb_parm h4; 607 #if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE) 608 struct inet6_skb_parm h6; 609 #endif 610 } header; /* For incoming frames */ 611 __u32 seq; /* Starting sequence number */ 612 __u32 end_seq; /* SEQ + FIN + SYN + datalen */ 613 __u32 when; /* used to compute rtt's */ 614 __u8 flags; /* TCP header flags. */ 615 616 /* NOTE: These must match up to the flags byte in a 617 * real TCP header. 618 */ 619 #define TCPCB_FLAG_FIN 0x01 620 #define TCPCB_FLAG_SYN 0x02 621 #define TCPCB_FLAG_RST 0x04 622 #define TCPCB_FLAG_PSH 0x08 623 #define TCPCB_FLAG_ACK 0x10 624 #define TCPCB_FLAG_URG 0x20 625 #define TCPCB_FLAG_ECE 0x40 626 #define TCPCB_FLAG_CWR 0x80 627 628 __u8 sacked; /* State flags for SACK/FACK. */ 629 #define TCPCB_SACKED_ACKED 0x01 /* SKB ACK'd by a SACK block */ 630 #define TCPCB_SACKED_RETRANS 0x02 /* SKB retransmitted */ 631 #define TCPCB_LOST 0x04 /* SKB is lost */ 632 #define TCPCB_TAGBITS 0x07 /* All tag bits */ 633 634 #define TCPCB_EVER_RETRANS 0x80 /* Ever retransmitted frame */ 635 #define TCPCB_RETRANS (TCPCB_SACKED_RETRANS|TCPCB_EVER_RETRANS) 636 637 __u32 ack_seq; /* Sequence number ACK'd */ 638 }; 639 640 #define TCP_SKB_CB(__skb) ((struct tcp_skb_cb *)&((__skb)->cb[0])) 641 642 /* Due to TSO, an SKB can be composed of multiple actual 643 * packets. To keep these tracked properly, we use this. 644 */ 645 static inline int tcp_skb_pcount(const struct sk_buff *skb) 646 { 647 return skb_shinfo(skb)->gso_segs; 648 } 649 650 /* This is valid iff tcp_skb_pcount() > 1. */ 651 static inline int tcp_skb_mss(const struct sk_buff *skb) 652 { 653 return skb_shinfo(skb)->gso_size; 654 } 655 656 /* Events passed to congestion control interface */ 657 enum tcp_ca_event { 658 CA_EVENT_TX_START, /* first transmit when no packets in flight */ 659 CA_EVENT_CWND_RESTART, /* congestion window restart */ 660 CA_EVENT_COMPLETE_CWR, /* end of congestion recovery */ 661 CA_EVENT_FRTO, /* fast recovery timeout */ 662 CA_EVENT_LOSS, /* loss timeout */ 663 CA_EVENT_FAST_ACK, /* in sequence ack */ 664 CA_EVENT_SLOW_ACK, /* other ack */ 665 }; 666 667 /* 668 * Interface for adding new TCP congestion control handlers 669 */ 670 #define TCP_CA_NAME_MAX 16 671 #define TCP_CA_MAX 128 672 #define TCP_CA_BUF_MAX (TCP_CA_NAME_MAX*TCP_CA_MAX) 673 674 #define TCP_CONG_NON_RESTRICTED 0x1 675 #define TCP_CONG_RTT_STAMP 0x2 676 677 struct tcp_congestion_ops { 678 struct list_head list; 679 unsigned long flags; 680 681 /* initialize private data (optional) */ 682 void (*init)(struct sock *sk); 683 /* cleanup private data (optional) */ 684 void (*release)(struct sock *sk); 685 686 /* return slow start threshold (required) */ 687 u32 (*ssthresh)(struct sock *sk); 688 /* lower bound for congestion window (optional) */ 689 u32 (*min_cwnd)(const struct sock *sk); 690 /* do new cwnd calculation (required) */ 691 void (*cong_avoid)(struct sock *sk, u32 ack, u32 in_flight); 692 /* call before changing ca_state (optional) */ 693 void (*set_state)(struct sock *sk, u8 new_state); 694 /* call when cwnd event occurs (optional) */ 695 void (*cwnd_event)(struct sock *sk, enum tcp_ca_event ev); 696 /* new value of cwnd after loss (optional) */ 697 u32 (*undo_cwnd)(struct sock *sk); 698 /* hook for packet ack accounting (optional) */ 699 void (*pkts_acked)(struct sock *sk, u32 num_acked, s32 rtt_us); 700 /* get info for inet_diag (optional) */ 701 void (*get_info)(struct sock *sk, u32 ext, struct sk_buff *skb); 702 703 char name[TCP_CA_NAME_MAX]; 704 struct module *owner; 705 }; 706 707 extern int tcp_register_congestion_control(struct tcp_congestion_ops *type); 708 extern void tcp_unregister_congestion_control(struct tcp_congestion_ops *type); 709 710 extern void tcp_init_congestion_control(struct sock *sk); 711 extern void tcp_cleanup_congestion_control(struct sock *sk); 712 extern int tcp_set_default_congestion_control(const char *name); 713 extern void tcp_get_default_congestion_control(char *name); 714 extern void tcp_get_available_congestion_control(char *buf, size_t len); 715 extern void tcp_get_allowed_congestion_control(char *buf, size_t len); 716 extern int tcp_set_allowed_congestion_control(char *allowed); 717 extern int tcp_set_congestion_control(struct sock *sk, const char *name); 718 extern void tcp_slow_start(struct tcp_sock *tp); 719 extern void tcp_cong_avoid_ai(struct tcp_sock *tp, u32 w); 720 721 extern struct tcp_congestion_ops tcp_init_congestion_ops; 722 extern u32 tcp_reno_ssthresh(struct sock *sk); 723 extern void tcp_reno_cong_avoid(struct sock *sk, u32 ack, u32 in_flight); 724 extern u32 tcp_reno_min_cwnd(const struct sock *sk); 725 extern struct tcp_congestion_ops tcp_reno; 726 727 static inline void tcp_set_ca_state(struct sock *sk, const u8 ca_state) 728 { 729 struct inet_connection_sock *icsk = inet_csk(sk); 730 731 if (icsk->icsk_ca_ops->set_state) 732 icsk->icsk_ca_ops->set_state(sk, ca_state); 733 icsk->icsk_ca_state = ca_state; 734 } 735 736 static inline void tcp_ca_event(struct sock *sk, const enum tcp_ca_event event) 737 { 738 const struct inet_connection_sock *icsk = inet_csk(sk); 739 740 if (icsk->icsk_ca_ops->cwnd_event) 741 icsk->icsk_ca_ops->cwnd_event(sk, event); 742 } 743 744 /* These functions determine how the current flow behaves in respect of SACK 745 * handling. SACK is negotiated with the peer, and therefore it can vary 746 * between different flows. 747 * 748 * tcp_is_sack - SACK enabled 749 * tcp_is_reno - No SACK 750 * tcp_is_fack - FACK enabled, implies SACK enabled 751 */ 752 static inline int tcp_is_sack(const struct tcp_sock *tp) 753 { 754 return tp->rx_opt.sack_ok; 755 } 756 757 static inline int tcp_is_reno(const struct tcp_sock *tp) 758 { 759 return !tcp_is_sack(tp); 760 } 761 762 static inline int tcp_is_fack(const struct tcp_sock *tp) 763 { 764 return tp->rx_opt.sack_ok & 2; 765 } 766 767 static inline void tcp_enable_fack(struct tcp_sock *tp) 768 { 769 tp->rx_opt.sack_ok |= 2; 770 } 771 772 static inline unsigned int tcp_left_out(const struct tcp_sock *tp) 773 { 774 return tp->sacked_out + tp->lost_out; 775 } 776 777 /* This determines how many packets are "in the network" to the best 778 * of our knowledge. In many cases it is conservative, but where 779 * detailed information is available from the receiver (via SACK 780 * blocks etc.) we can make more aggressive calculations. 781 * 782 * Use this for decisions involving congestion control, use just 783 * tp->packets_out to determine if the send queue is empty or not. 784 * 785 * Read this equation as: 786 * 787 * "Packets sent once on transmission queue" MINUS 788 * "Packets left network, but not honestly ACKed yet" PLUS 789 * "Packets fast retransmitted" 790 */ 791 static inline unsigned int tcp_packets_in_flight(const struct tcp_sock *tp) 792 { 793 return tp->packets_out - tcp_left_out(tp) + tp->retrans_out; 794 } 795 796 /* If cwnd > ssthresh, we may raise ssthresh to be half-way to cwnd. 797 * The exception is rate halving phase, when cwnd is decreasing towards 798 * ssthresh. 799 */ 800 static inline __u32 tcp_current_ssthresh(const struct sock *sk) 801 { 802 const struct tcp_sock *tp = tcp_sk(sk); 803 if ((1 << inet_csk(sk)->icsk_ca_state) & (TCPF_CA_CWR | TCPF_CA_Recovery)) 804 return tp->snd_ssthresh; 805 else 806 return max(tp->snd_ssthresh, 807 ((tp->snd_cwnd >> 1) + 808 (tp->snd_cwnd >> 2))); 809 } 810 811 /* Use define here intentionally to get WARN_ON location shown at the caller */ 812 #define tcp_verify_left_out(tp) WARN_ON(tcp_left_out(tp) > tp->packets_out) 813 814 extern void tcp_enter_cwr(struct sock *sk, const int set_ssthresh); 815 extern __u32 tcp_init_cwnd(struct tcp_sock *tp, struct dst_entry *dst); 816 817 /* Slow start with delack produces 3 packets of burst, so that 818 * it is safe "de facto". This will be the default - same as 819 * the default reordering threshold - but if reordering increases, 820 * we must be able to allow cwnd to burst at least this much in order 821 * to not pull it back when holes are filled. 822 */ 823 static __inline__ __u32 tcp_max_burst(const struct tcp_sock *tp) 824 { 825 return tp->reordering; 826 } 827 828 /* Returns end sequence number of the receiver's advertised window */ 829 static inline u32 tcp_wnd_end(const struct tcp_sock *tp) 830 { 831 return tp->snd_una + tp->snd_wnd; 832 } 833 extern int tcp_is_cwnd_limited(const struct sock *sk, u32 in_flight); 834 835 static inline void tcp_minshall_update(struct tcp_sock *tp, unsigned int mss, 836 const struct sk_buff *skb) 837 { 838 if (skb->len < mss) 839 tp->snd_sml = TCP_SKB_CB(skb)->end_seq; 840 } 841 842 static inline void tcp_check_probe_timer(struct sock *sk) 843 { 844 struct tcp_sock *tp = tcp_sk(sk); 845 const struct inet_connection_sock *icsk = inet_csk(sk); 846 847 if (!tp->packets_out && !icsk->icsk_pending) 848 inet_csk_reset_xmit_timer(sk, ICSK_TIME_PROBE0, 849 icsk->icsk_rto, TCP_RTO_MAX); 850 } 851 852 static inline void tcp_push_pending_frames(struct sock *sk) 853 { 854 struct tcp_sock *tp = tcp_sk(sk); 855 856 __tcp_push_pending_frames(sk, tcp_current_mss(sk), tp->nonagle); 857 } 858 859 static inline void tcp_init_wl(struct tcp_sock *tp, u32 seq) 860 { 861 tp->snd_wl1 = seq; 862 } 863 864 static inline void tcp_update_wl(struct tcp_sock *tp, u32 seq) 865 { 866 tp->snd_wl1 = seq; 867 } 868 869 /* 870 * Calculate(/check) TCP checksum 871 */ 872 static inline __sum16 tcp_v4_check(int len, __be32 saddr, 873 __be32 daddr, __wsum base) 874 { 875 return csum_tcpudp_magic(saddr,daddr,len,IPPROTO_TCP,base); 876 } 877 878 static inline __sum16 __tcp_checksum_complete(struct sk_buff *skb) 879 { 880 return __skb_checksum_complete(skb); 881 } 882 883 static inline int tcp_checksum_complete(struct sk_buff *skb) 884 { 885 return !skb_csum_unnecessary(skb) && 886 __tcp_checksum_complete(skb); 887 } 888 889 /* Prequeue for VJ style copy to user, combined with checksumming. */ 890 891 static inline void tcp_prequeue_init(struct tcp_sock *tp) 892 { 893 tp->ucopy.task = NULL; 894 tp->ucopy.len = 0; 895 tp->ucopy.memory = 0; 896 skb_queue_head_init(&tp->ucopy.prequeue); 897 #ifdef CONFIG_NET_DMA 898 tp->ucopy.dma_chan = NULL; 899 tp->ucopy.wakeup = 0; 900 tp->ucopy.pinned_list = NULL; 901 tp->ucopy.dma_cookie = 0; 902 #endif 903 } 904 905 /* Packet is added to VJ-style prequeue for processing in process 906 * context, if a reader task is waiting. Apparently, this exciting 907 * idea (VJ's mail "Re: query about TCP header on tcp-ip" of 07 Sep 93) 908 * failed somewhere. Latency? Burstiness? Well, at least now we will 909 * see, why it failed. 8)8) --ANK 910 * 911 * NOTE: is this not too big to inline? 912 */ 913 static inline int tcp_prequeue(struct sock *sk, struct sk_buff *skb) 914 { 915 struct tcp_sock *tp = tcp_sk(sk); 916 917 if (sysctl_tcp_low_latency || !tp->ucopy.task) 918 return 0; 919 920 __skb_queue_tail(&tp->ucopy.prequeue, skb); 921 tp->ucopy.memory += skb->truesize; 922 if (tp->ucopy.memory > sk->sk_rcvbuf) { 923 struct sk_buff *skb1; 924 925 BUG_ON(sock_owned_by_user(sk)); 926 927 while ((skb1 = __skb_dequeue(&tp->ucopy.prequeue)) != NULL) { 928 sk_backlog_rcv(sk, skb1); 929 NET_INC_STATS_BH(sock_net(sk), 930 LINUX_MIB_TCPPREQUEUEDROPPED); 931 } 932 933 tp->ucopy.memory = 0; 934 } else if (skb_queue_len(&tp->ucopy.prequeue) == 1) { 935 wake_up_interruptible_poll(sk->sk_sleep, 936 POLLIN | POLLRDNORM | POLLRDBAND); 937 if (!inet_csk_ack_scheduled(sk)) 938 inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK, 939 (3 * tcp_rto_min(sk)) / 4, 940 TCP_RTO_MAX); 941 } 942 return 1; 943 } 944 945 946 #undef STATE_TRACE 947 948 #ifdef STATE_TRACE 949 static const char *statename[]={ 950 "Unused","Established","Syn Sent","Syn Recv", 951 "Fin Wait 1","Fin Wait 2","Time Wait", "Close", 952 "Close Wait","Last ACK","Listen","Closing" 953 }; 954 #endif 955 extern void tcp_set_state(struct sock *sk, int state); 956 957 extern void tcp_done(struct sock *sk); 958 959 static inline void tcp_sack_reset(struct tcp_options_received *rx_opt) 960 { 961 rx_opt->dsack = 0; 962 rx_opt->num_sacks = 0; 963 } 964 965 /* Determine a window scaling and initial window to offer. */ 966 extern void tcp_select_initial_window(int __space, __u32 mss, 967 __u32 *rcv_wnd, __u32 *window_clamp, 968 int wscale_ok, __u8 *rcv_wscale); 969 970 static inline int tcp_win_from_space(int space) 971 { 972 return sysctl_tcp_adv_win_scale<=0 ? 973 (space>>(-sysctl_tcp_adv_win_scale)) : 974 space - (space>>sysctl_tcp_adv_win_scale); 975 } 976 977 /* Note: caller must be prepared to deal with negative returns */ 978 static inline int tcp_space(const struct sock *sk) 979 { 980 return tcp_win_from_space(sk->sk_rcvbuf - 981 atomic_read(&sk->sk_rmem_alloc)); 982 } 983 984 static inline int tcp_full_space(const struct sock *sk) 985 { 986 return tcp_win_from_space(sk->sk_rcvbuf); 987 } 988 989 static inline void tcp_openreq_init(struct request_sock *req, 990 struct tcp_options_received *rx_opt, 991 struct sk_buff *skb) 992 { 993 struct inet_request_sock *ireq = inet_rsk(req); 994 995 req->rcv_wnd = 0; /* So that tcp_send_synack() knows! */ 996 req->cookie_ts = 0; 997 tcp_rsk(req)->rcv_isn = TCP_SKB_CB(skb)->seq; 998 req->mss = rx_opt->mss_clamp; 999 req->ts_recent = rx_opt->saw_tstamp ? rx_opt->rcv_tsval : 0; 1000 ireq->tstamp_ok = rx_opt->tstamp_ok; 1001 ireq->sack_ok = rx_opt->sack_ok; 1002 ireq->snd_wscale = rx_opt->snd_wscale; 1003 ireq->wscale_ok = rx_opt->wscale_ok; 1004 ireq->acked = 0; 1005 ireq->ecn_ok = 0; 1006 ireq->rmt_port = tcp_hdr(skb)->source; 1007 ireq->loc_port = tcp_hdr(skb)->dest; 1008 } 1009 1010 extern void tcp_enter_memory_pressure(struct sock *sk); 1011 1012 static inline int keepalive_intvl_when(const struct tcp_sock *tp) 1013 { 1014 return tp->keepalive_intvl ? : sysctl_tcp_keepalive_intvl; 1015 } 1016 1017 static inline int keepalive_time_when(const struct tcp_sock *tp) 1018 { 1019 return tp->keepalive_time ? : sysctl_tcp_keepalive_time; 1020 } 1021 1022 static inline int keepalive_probes(const struct tcp_sock *tp) 1023 { 1024 return tp->keepalive_probes ? : sysctl_tcp_keepalive_probes; 1025 } 1026 1027 static inline int tcp_fin_time(const struct sock *sk) 1028 { 1029 int fin_timeout = tcp_sk(sk)->linger2 ? : sysctl_tcp_fin_timeout; 1030 const int rto = inet_csk(sk)->icsk_rto; 1031 1032 if (fin_timeout < (rto << 2) - (rto >> 1)) 1033 fin_timeout = (rto << 2) - (rto >> 1); 1034 1035 return fin_timeout; 1036 } 1037 1038 static inline int tcp_paws_check(const struct tcp_options_received *rx_opt, 1039 int paws_win) 1040 { 1041 if ((s32)(rx_opt->ts_recent - rx_opt->rcv_tsval) <= paws_win) 1042 return 1; 1043 if (unlikely(get_seconds() >= rx_opt->ts_recent_stamp + TCP_PAWS_24DAYS)) 1044 return 1; 1045 1046 return 0; 1047 } 1048 1049 static inline int tcp_paws_reject(const struct tcp_options_received *rx_opt, 1050 int rst) 1051 { 1052 if (tcp_paws_check(rx_opt, 0)) 1053 return 0; 1054 1055 /* RST segments are not recommended to carry timestamp, 1056 and, if they do, it is recommended to ignore PAWS because 1057 "their cleanup function should take precedence over timestamps." 1058 Certainly, it is mistake. It is necessary to understand the reasons 1059 of this constraint to relax it: if peer reboots, clock may go 1060 out-of-sync and half-open connections will not be reset. 1061 Actually, the problem would be not existing if all 1062 the implementations followed draft about maintaining clock 1063 via reboots. Linux-2.2 DOES NOT! 1064 1065 However, we can relax time bounds for RST segments to MSL. 1066 */ 1067 if (rst && get_seconds() >= rx_opt->ts_recent_stamp + TCP_PAWS_MSL) 1068 return 0; 1069 return 1; 1070 } 1071 1072 #define TCP_CHECK_TIMER(sk) do { } while (0) 1073 1074 static inline void tcp_mib_init(struct net *net) 1075 { 1076 /* See RFC 2012 */ 1077 TCP_ADD_STATS_USER(net, TCP_MIB_RTOALGORITHM, 1); 1078 TCP_ADD_STATS_USER(net, TCP_MIB_RTOMIN, TCP_RTO_MIN*1000/HZ); 1079 TCP_ADD_STATS_USER(net, TCP_MIB_RTOMAX, TCP_RTO_MAX*1000/HZ); 1080 TCP_ADD_STATS_USER(net, TCP_MIB_MAXCONN, -1); 1081 } 1082 1083 /* from STCP */ 1084 static inline void tcp_clear_retrans_hints_partial(struct tcp_sock *tp) 1085 { 1086 tp->lost_skb_hint = NULL; 1087 tp->scoreboard_skb_hint = NULL; 1088 } 1089 1090 static inline void tcp_clear_all_retrans_hints(struct tcp_sock *tp) 1091 { 1092 tcp_clear_retrans_hints_partial(tp); 1093 tp->retransmit_skb_hint = NULL; 1094 } 1095 1096 /* MD5 Signature */ 1097 struct crypto_hash; 1098 1099 /* - key database */ 1100 struct tcp_md5sig_key { 1101 u8 *key; 1102 u8 keylen; 1103 }; 1104 1105 struct tcp4_md5sig_key { 1106 struct tcp_md5sig_key base; 1107 __be32 addr; 1108 }; 1109 1110 struct tcp6_md5sig_key { 1111 struct tcp_md5sig_key base; 1112 #if 0 1113 u32 scope_id; /* XXX */ 1114 #endif 1115 struct in6_addr addr; 1116 }; 1117 1118 /* - sock block */ 1119 struct tcp_md5sig_info { 1120 struct tcp4_md5sig_key *keys4; 1121 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) 1122 struct tcp6_md5sig_key *keys6; 1123 u32 entries6; 1124 u32 alloced6; 1125 #endif 1126 u32 entries4; 1127 u32 alloced4; 1128 }; 1129 1130 /* - pseudo header */ 1131 struct tcp4_pseudohdr { 1132 __be32 saddr; 1133 __be32 daddr; 1134 __u8 pad; 1135 __u8 protocol; 1136 __be16 len; 1137 }; 1138 1139 struct tcp6_pseudohdr { 1140 struct in6_addr saddr; 1141 struct in6_addr daddr; 1142 __be32 len; 1143 __be32 protocol; /* including padding */ 1144 }; 1145 1146 union tcp_md5sum_block { 1147 struct tcp4_pseudohdr ip4; 1148 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) 1149 struct tcp6_pseudohdr ip6; 1150 #endif 1151 }; 1152 1153 /* - pool: digest algorithm, hash description and scratch buffer */ 1154 struct tcp_md5sig_pool { 1155 struct hash_desc md5_desc; 1156 union tcp_md5sum_block md5_blk; 1157 }; 1158 1159 #define TCP_MD5SIG_MAXKEYS (~(u32)0) /* really?! */ 1160 1161 /* - functions */ 1162 extern int tcp_v4_md5_hash_skb(char *md5_hash, 1163 struct tcp_md5sig_key *key, 1164 struct sock *sk, 1165 struct request_sock *req, 1166 struct sk_buff *skb); 1167 1168 extern struct tcp_md5sig_key *tcp_v4_md5_lookup(struct sock *sk, 1169 struct sock *addr_sk); 1170 1171 extern int tcp_v4_md5_do_add(struct sock *sk, 1172 __be32 addr, 1173 u8 *newkey, 1174 u8 newkeylen); 1175 1176 extern int tcp_v4_md5_do_del(struct sock *sk, 1177 __be32 addr); 1178 1179 #ifdef CONFIG_TCP_MD5SIG 1180 #define tcp_twsk_md5_key(twsk) ((twsk)->tw_md5_keylen ? \ 1181 &(struct tcp_md5sig_key) { \ 1182 .key = (twsk)->tw_md5_key, \ 1183 .keylen = (twsk)->tw_md5_keylen, \ 1184 } : NULL) 1185 #else 1186 #define tcp_twsk_md5_key(twsk) NULL 1187 #endif 1188 1189 extern struct tcp_md5sig_pool **tcp_alloc_md5sig_pool(struct sock *); 1190 extern void tcp_free_md5sig_pool(void); 1191 1192 extern struct tcp_md5sig_pool *__tcp_get_md5sig_pool(int cpu); 1193 extern void __tcp_put_md5sig_pool(void); 1194 extern int tcp_md5_hash_header(struct tcp_md5sig_pool *, struct tcphdr *); 1195 extern int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *, struct sk_buff *, 1196 unsigned header_len); 1197 extern int tcp_md5_hash_key(struct tcp_md5sig_pool *hp, 1198 struct tcp_md5sig_key *key); 1199 1200 static inline 1201 struct tcp_md5sig_pool *tcp_get_md5sig_pool(void) 1202 { 1203 int cpu = get_cpu(); 1204 struct tcp_md5sig_pool *ret = __tcp_get_md5sig_pool(cpu); 1205 if (!ret) 1206 put_cpu(); 1207 return ret; 1208 } 1209 1210 static inline void tcp_put_md5sig_pool(void) 1211 { 1212 __tcp_put_md5sig_pool(); 1213 put_cpu(); 1214 } 1215 1216 /* write queue abstraction */ 1217 static inline void tcp_write_queue_purge(struct sock *sk) 1218 { 1219 struct sk_buff *skb; 1220 1221 while ((skb = __skb_dequeue(&sk->sk_write_queue)) != NULL) 1222 sk_wmem_free_skb(sk, skb); 1223 sk_mem_reclaim(sk); 1224 } 1225 1226 static inline struct sk_buff *tcp_write_queue_head(struct sock *sk) 1227 { 1228 return skb_peek(&sk->sk_write_queue); 1229 } 1230 1231 static inline struct sk_buff *tcp_write_queue_tail(struct sock *sk) 1232 { 1233 return skb_peek_tail(&sk->sk_write_queue); 1234 } 1235 1236 static inline struct sk_buff *tcp_write_queue_next(struct sock *sk, struct sk_buff *skb) 1237 { 1238 return skb_queue_next(&sk->sk_write_queue, skb); 1239 } 1240 1241 static inline struct sk_buff *tcp_write_queue_prev(struct sock *sk, struct sk_buff *skb) 1242 { 1243 return skb_queue_prev(&sk->sk_write_queue, skb); 1244 } 1245 1246 #define tcp_for_write_queue(skb, sk) \ 1247 skb_queue_walk(&(sk)->sk_write_queue, skb) 1248 1249 #define tcp_for_write_queue_from(skb, sk) \ 1250 skb_queue_walk_from(&(sk)->sk_write_queue, skb) 1251 1252 #define tcp_for_write_queue_from_safe(skb, tmp, sk) \ 1253 skb_queue_walk_from_safe(&(sk)->sk_write_queue, skb, tmp) 1254 1255 /* This function calculates a "timeout" which is equivalent to the timeout of a 1256 * TCP connection after "boundary" unsucessful, exponentially backed-off 1257 * retransmissions with an initial RTO of TCP_RTO_MIN. 1258 */ 1259 static inline bool retransmits_timed_out(const struct sock *sk, 1260 unsigned int boundary) 1261 { 1262 unsigned int timeout, linear_backoff_thresh; 1263 1264 if (!inet_csk(sk)->icsk_retransmits) 1265 return false; 1266 1267 linear_backoff_thresh = ilog2(TCP_RTO_MAX/TCP_RTO_MIN); 1268 1269 if (boundary <= linear_backoff_thresh) 1270 timeout = ((2 << boundary) - 1) * TCP_RTO_MIN; 1271 else 1272 timeout = ((2 << linear_backoff_thresh) - 1) * TCP_RTO_MIN + 1273 (boundary - linear_backoff_thresh) * TCP_RTO_MAX; 1274 1275 return (tcp_time_stamp - tcp_sk(sk)->retrans_stamp) >= timeout; 1276 } 1277 1278 static inline struct sk_buff *tcp_send_head(struct sock *sk) 1279 { 1280 return sk->sk_send_head; 1281 } 1282 1283 static inline bool tcp_skb_is_last(const struct sock *sk, 1284 const struct sk_buff *skb) 1285 { 1286 return skb_queue_is_last(&sk->sk_write_queue, skb); 1287 } 1288 1289 static inline void tcp_advance_send_head(struct sock *sk, struct sk_buff *skb) 1290 { 1291 if (tcp_skb_is_last(sk, skb)) 1292 sk->sk_send_head = NULL; 1293 else 1294 sk->sk_send_head = tcp_write_queue_next(sk, skb); 1295 } 1296 1297 static inline void tcp_check_send_head(struct sock *sk, struct sk_buff *skb_unlinked) 1298 { 1299 if (sk->sk_send_head == skb_unlinked) 1300 sk->sk_send_head = NULL; 1301 } 1302 1303 static inline void tcp_init_send_head(struct sock *sk) 1304 { 1305 sk->sk_send_head = NULL; 1306 } 1307 1308 static inline void __tcp_add_write_queue_tail(struct sock *sk, struct sk_buff *skb) 1309 { 1310 __skb_queue_tail(&sk->sk_write_queue, skb); 1311 } 1312 1313 static inline void tcp_add_write_queue_tail(struct sock *sk, struct sk_buff *skb) 1314 { 1315 __tcp_add_write_queue_tail(sk, skb); 1316 1317 /* Queue it, remembering where we must start sending. */ 1318 if (sk->sk_send_head == NULL) { 1319 sk->sk_send_head = skb; 1320 1321 if (tcp_sk(sk)->highest_sack == NULL) 1322 tcp_sk(sk)->highest_sack = skb; 1323 } 1324 } 1325 1326 static inline void __tcp_add_write_queue_head(struct sock *sk, struct sk_buff *skb) 1327 { 1328 __skb_queue_head(&sk->sk_write_queue, skb); 1329 } 1330 1331 /* Insert buff after skb on the write queue of sk. */ 1332 static inline void tcp_insert_write_queue_after(struct sk_buff *skb, 1333 struct sk_buff *buff, 1334 struct sock *sk) 1335 { 1336 __skb_queue_after(&sk->sk_write_queue, skb, buff); 1337 } 1338 1339 /* Insert new before skb on the write queue of sk. */ 1340 static inline void tcp_insert_write_queue_before(struct sk_buff *new, 1341 struct sk_buff *skb, 1342 struct sock *sk) 1343 { 1344 __skb_queue_before(&sk->sk_write_queue, skb, new); 1345 1346 if (sk->sk_send_head == skb) 1347 sk->sk_send_head = new; 1348 } 1349 1350 static inline void tcp_unlink_write_queue(struct sk_buff *skb, struct sock *sk) 1351 { 1352 __skb_unlink(skb, &sk->sk_write_queue); 1353 } 1354 1355 static inline int tcp_write_queue_empty(struct sock *sk) 1356 { 1357 return skb_queue_empty(&sk->sk_write_queue); 1358 } 1359 1360 /* Start sequence of the highest skb with SACKed bit, valid only if 1361 * sacked > 0 or when the caller has ensured validity by itself. 1362 */ 1363 static inline u32 tcp_highest_sack_seq(struct tcp_sock *tp) 1364 { 1365 if (!tp->sacked_out) 1366 return tp->snd_una; 1367 1368 if (tp->highest_sack == NULL) 1369 return tp->snd_nxt; 1370 1371 return TCP_SKB_CB(tp->highest_sack)->seq; 1372 } 1373 1374 static inline void tcp_advance_highest_sack(struct sock *sk, struct sk_buff *skb) 1375 { 1376 tcp_sk(sk)->highest_sack = tcp_skb_is_last(sk, skb) ? NULL : 1377 tcp_write_queue_next(sk, skb); 1378 } 1379 1380 static inline struct sk_buff *tcp_highest_sack(struct sock *sk) 1381 { 1382 return tcp_sk(sk)->highest_sack; 1383 } 1384 1385 static inline void tcp_highest_sack_reset(struct sock *sk) 1386 { 1387 tcp_sk(sk)->highest_sack = tcp_write_queue_head(sk); 1388 } 1389 1390 /* Called when old skb is about to be deleted (to be combined with new skb) */ 1391 static inline void tcp_highest_sack_combine(struct sock *sk, 1392 struct sk_buff *old, 1393 struct sk_buff *new) 1394 { 1395 if (tcp_sk(sk)->sacked_out && (old == tcp_sk(sk)->highest_sack)) 1396 tcp_sk(sk)->highest_sack = new; 1397 } 1398 1399 /* /proc */ 1400 enum tcp_seq_states { 1401 TCP_SEQ_STATE_LISTENING, 1402 TCP_SEQ_STATE_OPENREQ, 1403 TCP_SEQ_STATE_ESTABLISHED, 1404 TCP_SEQ_STATE_TIME_WAIT, 1405 }; 1406 1407 struct tcp_seq_afinfo { 1408 char *name; 1409 sa_family_t family; 1410 struct file_operations seq_fops; 1411 struct seq_operations seq_ops; 1412 }; 1413 1414 struct tcp_iter_state { 1415 struct seq_net_private p; 1416 sa_family_t family; 1417 enum tcp_seq_states state; 1418 struct sock *syn_wait_sk; 1419 int bucket, sbucket, num, uid; 1420 }; 1421 1422 extern int tcp_proc_register(struct net *net, struct tcp_seq_afinfo *afinfo); 1423 extern void tcp_proc_unregister(struct net *net, struct tcp_seq_afinfo *afinfo); 1424 1425 extern struct request_sock_ops tcp_request_sock_ops; 1426 extern struct request_sock_ops tcp6_request_sock_ops; 1427 1428 extern void tcp_v4_destroy_sock(struct sock *sk); 1429 1430 extern int tcp_v4_gso_send_check(struct sk_buff *skb); 1431 extern struct sk_buff *tcp_tso_segment(struct sk_buff *skb, int features); 1432 extern struct sk_buff **tcp_gro_receive(struct sk_buff **head, 1433 struct sk_buff *skb); 1434 extern struct sk_buff **tcp4_gro_receive(struct sk_buff **head, 1435 struct sk_buff *skb); 1436 extern int tcp_gro_complete(struct sk_buff *skb); 1437 extern int tcp4_gro_complete(struct sk_buff *skb); 1438 1439 #ifdef CONFIG_PROC_FS 1440 extern int tcp4_proc_init(void); 1441 extern void tcp4_proc_exit(void); 1442 #endif 1443 1444 /* TCP af-specific functions */ 1445 struct tcp_sock_af_ops { 1446 #ifdef CONFIG_TCP_MD5SIG 1447 struct tcp_md5sig_key *(*md5_lookup) (struct sock *sk, 1448 struct sock *addr_sk); 1449 int (*calc_md5_hash) (char *location, 1450 struct tcp_md5sig_key *md5, 1451 struct sock *sk, 1452 struct request_sock *req, 1453 struct sk_buff *skb); 1454 int (*md5_add) (struct sock *sk, 1455 struct sock *addr_sk, 1456 u8 *newkey, 1457 u8 len); 1458 int (*md5_parse) (struct sock *sk, 1459 char __user *optval, 1460 int optlen); 1461 #endif 1462 }; 1463 1464 struct tcp_request_sock_ops { 1465 #ifdef CONFIG_TCP_MD5SIG 1466 struct tcp_md5sig_key *(*md5_lookup) (struct sock *sk, 1467 struct request_sock *req); 1468 int (*calc_md5_hash) (char *location, 1469 struct tcp_md5sig_key *md5, 1470 struct sock *sk, 1471 struct request_sock *req, 1472 struct sk_buff *skb); 1473 #endif 1474 }; 1475 1476 extern void tcp_v4_init(void); 1477 extern void tcp_init(void); 1478 1479 #endif /* _TCP_H */ 1480