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 #include <linux/kref.h> 34 35 #include <net/inet_connection_sock.h> 36 #include <net/inet_timewait_sock.h> 37 #include <net/inet_hashtables.h> 38 #include <net/checksum.h> 39 #include <net/request_sock.h> 40 #include <net/sock.h> 41 #include <net/snmp.h> 42 #include <net/ip.h> 43 #include <net/tcp_states.h> 44 #include <net/inet_ecn.h> 45 #include <net/dst.h> 46 47 #include <linux/seq_file.h> 48 49 extern struct inet_hashinfo tcp_hashinfo; 50 51 extern struct percpu_counter tcp_orphan_count; 52 extern void tcp_time_wait(struct sock *sk, int state, int timeo); 53 54 #define MAX_TCP_HEADER (128 + MAX_HEADER) 55 #define MAX_TCP_OPTION_SPACE 40 56 57 /* 58 * Never offer a window over 32767 without using window scaling. Some 59 * poor stacks do signed 16bit maths! 60 */ 61 #define MAX_TCP_WINDOW 32767U 62 63 /* Minimal accepted MSS. It is (60+60+8) - (20+20). */ 64 #define TCP_MIN_MSS 88U 65 66 /* The least MTU to use for probing */ 67 #define TCP_BASE_MSS 512 68 69 /* After receiving this amount of duplicate ACKs fast retransmit starts. */ 70 #define TCP_FASTRETRANS_THRESH 3 71 72 /* Maximal reordering. */ 73 #define TCP_MAX_REORDERING 127 74 75 /* Maximal number of ACKs sent quickly to accelerate slow-start. */ 76 #define TCP_MAX_QUICKACKS 16U 77 78 /* urg_data states */ 79 #define TCP_URG_VALID 0x0100 80 #define TCP_URG_NOTYET 0x0200 81 #define TCP_URG_READ 0x0400 82 83 #define TCP_RETR1 3 /* 84 * This is how many retries it does before it 85 * tries to figure out if the gateway is 86 * down. Minimal RFC value is 3; it corresponds 87 * to ~3sec-8min depending on RTO. 88 */ 89 90 #define TCP_RETR2 15 /* 91 * This should take at least 92 * 90 minutes to time out. 93 * RFC1122 says that the limit is 100 sec. 94 * 15 is ~13-30min depending on RTO. 95 */ 96 97 #define TCP_SYN_RETRIES 5 /* number of times to retry active opening a 98 * connection: ~180sec is RFC minimum */ 99 100 #define TCP_SYNACK_RETRIES 5 /* number of times to retry passive opening a 101 * connection: ~180sec is RFC minimum */ 102 103 104 #define TCP_ORPHAN_RETRIES 7 /* number of times to retry on an orphaned 105 * socket. 7 is ~50sec-16min. 106 */ 107 108 109 #define TCP_TIMEWAIT_LEN (60*HZ) /* how long to wait to destroy TIME-WAIT 110 * state, about 60 seconds */ 111 #define TCP_FIN_TIMEOUT TCP_TIMEWAIT_LEN 112 /* BSD style FIN_WAIT2 deadlock breaker. 113 * It used to be 3min, new value is 60sec, 114 * to combine FIN-WAIT-2 timeout with 115 * TIME-WAIT timer. 116 */ 117 118 #define TCP_DELACK_MAX ((unsigned)(HZ/5)) /* maximal time to delay before sending an ACK */ 119 #if HZ >= 100 120 #define TCP_DELACK_MIN ((unsigned)(HZ/25)) /* minimal time to delay before sending an ACK */ 121 #define TCP_ATO_MIN ((unsigned)(HZ/25)) 122 #else 123 #define TCP_DELACK_MIN 4U 124 #define TCP_ATO_MIN 4U 125 #endif 126 #define TCP_RTO_MAX ((unsigned)(120*HZ)) 127 #define TCP_RTO_MIN ((unsigned)(HZ/5)) 128 #define TCP_TIMEOUT_INIT ((unsigned)(3*HZ)) /* RFC 1122 initial RTO value */ 129 130 #define TCP_RESOURCE_PROBE_INTERVAL ((unsigned)(HZ/2U)) /* Maximal interval between probes 131 * for local resources. 132 */ 133 134 #define TCP_KEEPALIVE_TIME (120*60*HZ) /* two hours */ 135 #define TCP_KEEPALIVE_PROBES 9 /* Max of 9 keepalive probes */ 136 #define TCP_KEEPALIVE_INTVL (75*HZ) 137 138 #define MAX_TCP_KEEPIDLE 32767 139 #define MAX_TCP_KEEPINTVL 32767 140 #define MAX_TCP_KEEPCNT 127 141 #define MAX_TCP_SYNCNT 127 142 143 #define TCP_SYNQ_INTERVAL (HZ/5) /* Period of SYNACK timer */ 144 145 #define TCP_PAWS_24DAYS (60 * 60 * 24 * 24) 146 #define TCP_PAWS_MSL 60 /* Per-host timestamps are invalidated 147 * after this time. It should be equal 148 * (or greater than) TCP_TIMEWAIT_LEN 149 * to provide reliability equal to one 150 * provided by timewait state. 151 */ 152 #define TCP_PAWS_WINDOW 1 /* Replay window for per-host 153 * timestamps. It must be less than 154 * minimal timewait lifetime. 155 */ 156 /* 157 * TCP option 158 */ 159 160 #define TCPOPT_NOP 1 /* Padding */ 161 #define TCPOPT_EOL 0 /* End of options */ 162 #define TCPOPT_MSS 2 /* Segment size negotiating */ 163 #define TCPOPT_WINDOW 3 /* Window scaling */ 164 #define TCPOPT_SACK_PERM 4 /* SACK Permitted */ 165 #define TCPOPT_SACK 5 /* SACK Block */ 166 #define TCPOPT_TIMESTAMP 8 /* Better RTT estimations/PAWS */ 167 #define TCPOPT_MD5SIG 19 /* MD5 Signature (RFC2385) */ 168 #define TCPOPT_COOKIE 253 /* Cookie extension (experimental) */ 169 170 /* 171 * TCP option lengths 172 */ 173 174 #define TCPOLEN_MSS 4 175 #define TCPOLEN_WINDOW 3 176 #define TCPOLEN_SACK_PERM 2 177 #define TCPOLEN_TIMESTAMP 10 178 #define TCPOLEN_MD5SIG 18 179 #define TCPOLEN_COOKIE_BASE 2 /* Cookie-less header extension */ 180 #define TCPOLEN_COOKIE_PAIR 3 /* Cookie pair header extension */ 181 #define TCPOLEN_COOKIE_MIN (TCPOLEN_COOKIE_BASE+TCP_COOKIE_MIN) 182 #define TCPOLEN_COOKIE_MAX (TCPOLEN_COOKIE_BASE+TCP_COOKIE_MAX) 183 184 /* But this is what stacks really send out. */ 185 #define TCPOLEN_TSTAMP_ALIGNED 12 186 #define TCPOLEN_WSCALE_ALIGNED 4 187 #define TCPOLEN_SACKPERM_ALIGNED 4 188 #define TCPOLEN_SACK_BASE 2 189 #define TCPOLEN_SACK_BASE_ALIGNED 4 190 #define TCPOLEN_SACK_PERBLOCK 8 191 #define TCPOLEN_MD5SIG_ALIGNED 20 192 #define TCPOLEN_MSS_ALIGNED 4 193 194 /* Flags in tp->nonagle */ 195 #define TCP_NAGLE_OFF 1 /* Nagle's algo is disabled */ 196 #define TCP_NAGLE_CORK 2 /* Socket is corked */ 197 #define TCP_NAGLE_PUSH 4 /* Cork is overridden for already queued data */ 198 199 extern struct inet_timewait_death_row tcp_death_row; 200 201 /* sysctl variables for tcp */ 202 extern int sysctl_tcp_timestamps; 203 extern int sysctl_tcp_window_scaling; 204 extern int sysctl_tcp_sack; 205 extern int sysctl_tcp_fin_timeout; 206 extern int sysctl_tcp_keepalive_time; 207 extern int sysctl_tcp_keepalive_probes; 208 extern int sysctl_tcp_keepalive_intvl; 209 extern int sysctl_tcp_syn_retries; 210 extern int sysctl_tcp_synack_retries; 211 extern int sysctl_tcp_retries1; 212 extern int sysctl_tcp_retries2; 213 extern int sysctl_tcp_orphan_retries; 214 extern int sysctl_tcp_syncookies; 215 extern int sysctl_tcp_retrans_collapse; 216 extern int sysctl_tcp_stdurg; 217 extern int sysctl_tcp_rfc1337; 218 extern int sysctl_tcp_abort_on_overflow; 219 extern int sysctl_tcp_max_orphans; 220 extern int sysctl_tcp_fack; 221 extern int sysctl_tcp_reordering; 222 extern int sysctl_tcp_ecn; 223 extern int sysctl_tcp_dsack; 224 extern int sysctl_tcp_mem[3]; 225 extern int sysctl_tcp_wmem[3]; 226 extern int sysctl_tcp_rmem[3]; 227 extern int sysctl_tcp_app_win; 228 extern int sysctl_tcp_adv_win_scale; 229 extern int sysctl_tcp_tw_reuse; 230 extern int sysctl_tcp_frto; 231 extern int sysctl_tcp_frto_response; 232 extern int sysctl_tcp_low_latency; 233 extern int sysctl_tcp_dma_copybreak; 234 extern int sysctl_tcp_nometrics_save; 235 extern int sysctl_tcp_moderate_rcvbuf; 236 extern int sysctl_tcp_tso_win_divisor; 237 extern int sysctl_tcp_abc; 238 extern int sysctl_tcp_mtu_probing; 239 extern int sysctl_tcp_base_mss; 240 extern int sysctl_tcp_workaround_signed_windows; 241 extern int sysctl_tcp_slow_start_after_idle; 242 extern int sysctl_tcp_max_ssthresh; 243 extern int sysctl_tcp_cookie_size; 244 245 extern atomic_t tcp_memory_allocated; 246 extern struct percpu_counter tcp_sockets_allocated; 247 extern int tcp_memory_pressure; 248 249 /* 250 * The next routines deal with comparing 32 bit unsigned ints 251 * and worry about wraparound (automatic with unsigned arithmetic). 252 */ 253 254 static inline int before(__u32 seq1, __u32 seq2) 255 { 256 return (__s32)(seq1-seq2) < 0; 257 } 258 #define after(seq2, seq1) before(seq1, seq2) 259 260 /* is s2<=s1<=s3 ? */ 261 static inline int between(__u32 seq1, __u32 seq2, __u32 seq3) 262 { 263 return seq3 - seq2 >= seq1 - seq2; 264 } 265 266 static inline int tcp_too_many_orphans(struct sock *sk, int num) 267 { 268 return (num > sysctl_tcp_max_orphans) || 269 (sk->sk_wmem_queued > SOCK_MIN_SNDBUF && 270 atomic_read(&tcp_memory_allocated) > sysctl_tcp_mem[2]); 271 } 272 273 /* syncookies: remember time of last synqueue overflow */ 274 static inline void tcp_synq_overflow(struct sock *sk) 275 { 276 tcp_sk(sk)->rx_opt.ts_recent_stamp = jiffies; 277 } 278 279 /* syncookies: no recent synqueue overflow on this listening socket? */ 280 static inline int tcp_synq_no_recent_overflow(const struct sock *sk) 281 { 282 unsigned long last_overflow = tcp_sk(sk)->rx_opt.ts_recent_stamp; 283 return time_after(jiffies, last_overflow + TCP_TIMEOUT_INIT); 284 } 285 286 extern struct proto tcp_prot; 287 288 #define TCP_INC_STATS(net, field) SNMP_INC_STATS((net)->mib.tcp_statistics, field) 289 #define TCP_INC_STATS_BH(net, field) SNMP_INC_STATS_BH((net)->mib.tcp_statistics, field) 290 #define TCP_DEC_STATS(net, field) SNMP_DEC_STATS((net)->mib.tcp_statistics, field) 291 #define TCP_ADD_STATS_USER(net, field, val) SNMP_ADD_STATS_USER((net)->mib.tcp_statistics, field, val) 292 293 extern void tcp_v4_err(struct sk_buff *skb, u32); 294 295 extern void tcp_shutdown (struct sock *sk, int how); 296 297 extern int tcp_v4_rcv(struct sk_buff *skb); 298 299 extern int tcp_v4_remember_stamp(struct sock *sk); 300 301 extern int tcp_v4_tw_remember_stamp(struct inet_timewait_sock *tw); 302 303 extern int tcp_sendmsg(struct kiocb *iocb, struct socket *sock, 304 struct msghdr *msg, size_t size); 305 extern ssize_t tcp_sendpage(struct socket *sock, struct page *page, int offset, size_t size, int flags); 306 307 extern int tcp_ioctl(struct sock *sk, 308 int cmd, 309 unsigned long arg); 310 311 extern int tcp_rcv_state_process(struct sock *sk, 312 struct sk_buff *skb, 313 struct tcphdr *th, 314 unsigned len); 315 316 extern int tcp_rcv_established(struct sock *sk, 317 struct sk_buff *skb, 318 struct tcphdr *th, 319 unsigned len); 320 321 extern void tcp_rcv_space_adjust(struct sock *sk); 322 323 extern void tcp_cleanup_rbuf(struct sock *sk, int copied); 324 325 extern int tcp_twsk_unique(struct sock *sk, 326 struct sock *sktw, void *twp); 327 328 extern void tcp_twsk_destructor(struct sock *sk); 329 330 extern ssize_t tcp_splice_read(struct socket *sk, loff_t *ppos, 331 struct pipe_inode_info *pipe, size_t len, unsigned int flags); 332 333 static inline void tcp_dec_quickack_mode(struct sock *sk, 334 const unsigned int pkts) 335 { 336 struct inet_connection_sock *icsk = inet_csk(sk); 337 338 if (icsk->icsk_ack.quick) { 339 if (pkts >= icsk->icsk_ack.quick) { 340 icsk->icsk_ack.quick = 0; 341 /* Leaving quickack mode we deflate ATO. */ 342 icsk->icsk_ack.ato = TCP_ATO_MIN; 343 } else 344 icsk->icsk_ack.quick -= pkts; 345 } 346 } 347 348 extern void tcp_enter_quickack_mode(struct sock *sk); 349 350 #define TCP_ECN_OK 1 351 #define TCP_ECN_QUEUE_CWR 2 352 #define TCP_ECN_DEMAND_CWR 4 353 354 static __inline__ void 355 TCP_ECN_create_request(struct request_sock *req, struct tcphdr *th) 356 { 357 if (sysctl_tcp_ecn && th->ece && th->cwr) 358 inet_rsk(req)->ecn_ok = 1; 359 } 360 361 enum tcp_tw_status { 362 TCP_TW_SUCCESS = 0, 363 TCP_TW_RST = 1, 364 TCP_TW_ACK = 2, 365 TCP_TW_SYN = 3 366 }; 367 368 369 extern enum tcp_tw_status tcp_timewait_state_process(struct inet_timewait_sock *tw, 370 struct sk_buff *skb, 371 const struct tcphdr *th); 372 373 extern struct sock * tcp_check_req(struct sock *sk,struct sk_buff *skb, 374 struct request_sock *req, 375 struct request_sock **prev); 376 extern int tcp_child_process(struct sock *parent, 377 struct sock *child, 378 struct sk_buff *skb); 379 extern int tcp_use_frto(struct sock *sk); 380 extern void tcp_enter_frto(struct sock *sk); 381 extern void tcp_enter_loss(struct sock *sk, int how); 382 extern void tcp_clear_retrans(struct tcp_sock *tp); 383 extern void tcp_update_metrics(struct sock *sk); 384 385 extern void tcp_close(struct sock *sk, 386 long timeout); 387 extern unsigned int tcp_poll(struct file * file, struct socket *sock, struct poll_table_struct *wait); 388 389 extern int tcp_getsockopt(struct sock *sk, int level, 390 int optname, 391 char __user *optval, 392 int __user *optlen); 393 extern int tcp_setsockopt(struct sock *sk, int level, 394 int optname, char __user *optval, 395 unsigned int optlen); 396 extern int compat_tcp_getsockopt(struct sock *sk, 397 int level, int optname, 398 char __user *optval, int __user *optlen); 399 extern int compat_tcp_setsockopt(struct sock *sk, 400 int level, int optname, 401 char __user *optval, unsigned int optlen); 402 extern void tcp_set_keepalive(struct sock *sk, int val); 403 extern int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, 404 struct msghdr *msg, 405 size_t len, int nonblock, 406 int flags, int *addr_len); 407 408 extern void tcp_parse_options(struct sk_buff *skb, 409 struct tcp_options_received *opt_rx, 410 u8 **hvpp, 411 int estab, 412 struct dst_entry *dst); 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 struct request_values *rvp); 448 449 extern int tcp_disconnect(struct sock *sk, int flags); 450 451 452 /* From syncookies.c */ 453 extern __u32 syncookie_secret[2][16-4+SHA_DIGEST_WORDS]; 454 extern struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb, 455 struct ip_options *opt); 456 extern __u32 cookie_v4_init_sequence(struct sock *sk, struct sk_buff *skb, 457 __u16 *mss); 458 459 extern __u32 cookie_init_timestamp(struct request_sock *req); 460 extern void cookie_check_timestamp(struct tcp_options_received *tcp_opt); 461 462 /* From net/ipv6/syncookies.c */ 463 extern struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb); 464 extern __u32 cookie_v6_init_sequence(struct sock *sk, struct sk_buff *skb, 465 __u16 *mss); 466 467 /* tcp_output.c */ 468 469 extern void __tcp_push_pending_frames(struct sock *sk, unsigned int cur_mss, 470 int nonagle); 471 extern int tcp_may_send_now(struct sock *sk); 472 extern int tcp_retransmit_skb(struct sock *, struct sk_buff *); 473 extern void tcp_retransmit_timer(struct sock *sk); 474 extern void tcp_xmit_retransmit_queue(struct sock *); 475 extern void tcp_simple_retransmit(struct sock *); 476 extern int tcp_trim_head(struct sock *, struct sk_buff *, u32); 477 extern int tcp_fragment(struct sock *, struct sk_buff *, u32, unsigned int); 478 479 extern void tcp_send_probe0(struct sock *); 480 extern void tcp_send_partial(struct sock *); 481 extern int tcp_write_wakeup(struct sock *); 482 extern void tcp_send_fin(struct sock *sk); 483 extern void tcp_send_active_reset(struct sock *sk, gfp_t priority); 484 extern int tcp_send_synack(struct sock *); 485 extern void tcp_push_one(struct sock *, unsigned int mss_now); 486 extern void tcp_send_ack(struct sock *sk); 487 extern void tcp_send_delayed_ack(struct sock *sk); 488 489 /* tcp_input.c */ 490 extern void tcp_cwnd_application_limited(struct sock *sk); 491 492 /* tcp_timer.c */ 493 extern void tcp_init_xmit_timers(struct sock *); 494 static inline void tcp_clear_xmit_timers(struct sock *sk) 495 { 496 inet_csk_clear_xmit_timers(sk); 497 } 498 499 extern unsigned int tcp_sync_mss(struct sock *sk, u32 pmtu); 500 extern unsigned int tcp_current_mss(struct sock *sk); 501 502 /* Bound MSS / TSO packet size with the half of the window */ 503 static inline int tcp_bound_to_half_wnd(struct tcp_sock *tp, int pktsize) 504 { 505 if (tp->max_window && pktsize > (tp->max_window >> 1)) 506 return max(tp->max_window >> 1, 68U - tp->tcp_header_len); 507 else 508 return pktsize; 509 } 510 511 /* tcp.c */ 512 extern void tcp_get_info(struct sock *, struct tcp_info *); 513 514 /* Read 'sendfile()'-style from a TCP socket */ 515 typedef int (*sk_read_actor_t)(read_descriptor_t *, struct sk_buff *, 516 unsigned int, size_t); 517 extern int tcp_read_sock(struct sock *sk, read_descriptor_t *desc, 518 sk_read_actor_t recv_actor); 519 520 extern void tcp_initialize_rcv_mss(struct sock *sk); 521 522 extern int tcp_mtu_to_mss(struct sock *sk, int pmtu); 523 extern int tcp_mss_to_mtu(struct sock *sk, int mss); 524 extern void tcp_mtup_init(struct sock *sk); 525 526 static inline void tcp_bound_rto(const struct sock *sk) 527 { 528 if (inet_csk(sk)->icsk_rto > TCP_RTO_MAX) 529 inet_csk(sk)->icsk_rto = TCP_RTO_MAX; 530 } 531 532 static inline u32 __tcp_set_rto(const struct tcp_sock *tp) 533 { 534 return (tp->srtt >> 3) + tp->rttvar; 535 } 536 537 static inline void __tcp_fast_path_on(struct tcp_sock *tp, u32 snd_wnd) 538 { 539 tp->pred_flags = htonl((tp->tcp_header_len << 26) | 540 ntohl(TCP_FLAG_ACK) | 541 snd_wnd); 542 } 543 544 static inline void tcp_fast_path_on(struct tcp_sock *tp) 545 { 546 __tcp_fast_path_on(tp, tp->snd_wnd >> tp->rx_opt.snd_wscale); 547 } 548 549 static inline void tcp_fast_path_check(struct sock *sk) 550 { 551 struct tcp_sock *tp = tcp_sk(sk); 552 553 if (skb_queue_empty(&tp->out_of_order_queue) && 554 tp->rcv_wnd && 555 atomic_read(&sk->sk_rmem_alloc) < sk->sk_rcvbuf && 556 !tp->urg_data) 557 tcp_fast_path_on(tp); 558 } 559 560 /* Compute the actual rto_min value */ 561 static inline u32 tcp_rto_min(struct sock *sk) 562 { 563 struct dst_entry *dst = __sk_dst_get(sk); 564 u32 rto_min = TCP_RTO_MIN; 565 566 if (dst && dst_metric_locked(dst, RTAX_RTO_MIN)) 567 rto_min = dst_metric_rtt(dst, RTAX_RTO_MIN); 568 return rto_min; 569 } 570 571 /* Compute the actual receive window we are currently advertising. 572 * Rcv_nxt can be after the window if our peer push more data 573 * than the offered window. 574 */ 575 static inline u32 tcp_receive_window(const struct tcp_sock *tp) 576 { 577 s32 win = tp->rcv_wup + tp->rcv_wnd - tp->rcv_nxt; 578 579 if (win < 0) 580 win = 0; 581 return (u32) win; 582 } 583 584 /* Choose a new window, without checks for shrinking, and without 585 * scaling applied to the result. The caller does these things 586 * if necessary. This is a "raw" window selection. 587 */ 588 extern u32 __tcp_select_window(struct sock *sk); 589 590 /* TCP timestamps are only 32-bits, this causes a slight 591 * complication on 64-bit systems since we store a snapshot 592 * of jiffies in the buffer control blocks below. We decided 593 * to use only the low 32-bits of jiffies and hide the ugly 594 * casts with the following macro. 595 */ 596 #define tcp_time_stamp ((__u32)(jiffies)) 597 598 /* This is what the send packet queuing engine uses to pass 599 * TCP per-packet control information to the transmission 600 * code. We also store the host-order sequence numbers in 601 * here too. This is 36 bytes on 32-bit architectures, 602 * 40 bytes on 64-bit machines, if this grows please adjust 603 * skbuff.h:skbuff->cb[xxx] size appropriately. 604 */ 605 struct tcp_skb_cb { 606 union { 607 struct inet_skb_parm h4; 608 #if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE) 609 struct inet6_skb_parm h6; 610 #endif 611 } header; /* For incoming frames */ 612 __u32 seq; /* Starting sequence number */ 613 __u32 end_seq; /* SEQ + FIN + SYN + datalen */ 614 __u32 when; /* used to compute rtt's */ 615 __u8 flags; /* TCP header flags. */ 616 617 /* NOTE: These must match up to the flags byte in a 618 * real TCP header. 619 */ 620 #define TCPCB_FLAG_FIN 0x01 621 #define TCPCB_FLAG_SYN 0x02 622 #define TCPCB_FLAG_RST 0x04 623 #define TCPCB_FLAG_PSH 0x08 624 #define TCPCB_FLAG_ACK 0x10 625 #define TCPCB_FLAG_URG 0x20 626 #define TCPCB_FLAG_ECE 0x40 627 #define TCPCB_FLAG_CWR 0x80 628 629 __u8 sacked; /* State flags for SACK/FACK. */ 630 #define TCPCB_SACKED_ACKED 0x01 /* SKB ACK'd by a SACK block */ 631 #define TCPCB_SACKED_RETRANS 0x02 /* SKB retransmitted */ 632 #define TCPCB_LOST 0x04 /* SKB is lost */ 633 #define TCPCB_TAGBITS 0x07 /* All tag bits */ 634 635 #define TCPCB_EVER_RETRANS 0x80 /* Ever retransmitted frame */ 636 #define TCPCB_RETRANS (TCPCB_SACKED_RETRANS|TCPCB_EVER_RETRANS) 637 638 __u32 ack_seq; /* Sequence number ACK'd */ 639 }; 640 641 #define TCP_SKB_CB(__skb) ((struct tcp_skb_cb *)&((__skb)->cb[0])) 642 643 /* Due to TSO, an SKB can be composed of multiple actual 644 * packets. To keep these tracked properly, we use this. 645 */ 646 static inline int tcp_skb_pcount(const struct sk_buff *skb) 647 { 648 return skb_shinfo(skb)->gso_segs; 649 } 650 651 /* This is valid iff tcp_skb_pcount() > 1. */ 652 static inline int tcp_skb_mss(const struct sk_buff *skb) 653 { 654 return skb_shinfo(skb)->gso_size; 655 } 656 657 /* Events passed to congestion control interface */ 658 enum tcp_ca_event { 659 CA_EVENT_TX_START, /* first transmit when no packets in flight */ 660 CA_EVENT_CWND_RESTART, /* congestion window restart */ 661 CA_EVENT_COMPLETE_CWR, /* end of congestion recovery */ 662 CA_EVENT_FRTO, /* fast recovery timeout */ 663 CA_EVENT_LOSS, /* loss timeout */ 664 CA_EVENT_FAST_ACK, /* in sequence ack */ 665 CA_EVENT_SLOW_ACK, /* other ack */ 666 }; 667 668 /* 669 * Interface for adding new TCP congestion control handlers 670 */ 671 #define TCP_CA_NAME_MAX 16 672 #define TCP_CA_MAX 128 673 #define TCP_CA_BUF_MAX (TCP_CA_NAME_MAX*TCP_CA_MAX) 674 675 #define TCP_CONG_NON_RESTRICTED 0x1 676 #define TCP_CONG_RTT_STAMP 0x2 677 678 struct tcp_congestion_ops { 679 struct list_head list; 680 unsigned long flags; 681 682 /* initialize private data (optional) */ 683 void (*init)(struct sock *sk); 684 /* cleanup private data (optional) */ 685 void (*release)(struct sock *sk); 686 687 /* return slow start threshold (required) */ 688 u32 (*ssthresh)(struct sock *sk); 689 /* lower bound for congestion window (optional) */ 690 u32 (*min_cwnd)(const struct sock *sk); 691 /* do new cwnd calculation (required) */ 692 void (*cong_avoid)(struct sock *sk, u32 ack, u32 in_flight); 693 /* call before changing ca_state (optional) */ 694 void (*set_state)(struct sock *sk, u8 new_state); 695 /* call when cwnd event occurs (optional) */ 696 void (*cwnd_event)(struct sock *sk, enum tcp_ca_event ev); 697 /* new value of cwnd after loss (optional) */ 698 u32 (*undo_cwnd)(struct sock *sk); 699 /* hook for packet ack accounting (optional) */ 700 void (*pkts_acked)(struct sock *sk, u32 num_acked, s32 rtt_us); 701 /* get info for inet_diag (optional) */ 702 void (*get_info)(struct sock *sk, u32 ext, struct sk_buff *skb); 703 704 char name[TCP_CA_NAME_MAX]; 705 struct module *owner; 706 }; 707 708 extern int tcp_register_congestion_control(struct tcp_congestion_ops *type); 709 extern void tcp_unregister_congestion_control(struct tcp_congestion_ops *type); 710 711 extern void tcp_init_congestion_control(struct sock *sk); 712 extern void tcp_cleanup_congestion_control(struct sock *sk); 713 extern int tcp_set_default_congestion_control(const char *name); 714 extern void tcp_get_default_congestion_control(char *name); 715 extern void tcp_get_available_congestion_control(char *buf, size_t len); 716 extern void tcp_get_allowed_congestion_control(char *buf, size_t len); 717 extern int tcp_set_allowed_congestion_control(char *allowed); 718 extern int tcp_set_congestion_control(struct sock *sk, const char *name); 719 extern void tcp_slow_start(struct tcp_sock *tp); 720 extern void tcp_cong_avoid_ai(struct tcp_sock *tp, u32 w); 721 722 extern struct tcp_congestion_ops tcp_init_congestion_ops; 723 extern u32 tcp_reno_ssthresh(struct sock *sk); 724 extern void tcp_reno_cong_avoid(struct sock *sk, u32 ack, u32 in_flight); 725 extern u32 tcp_reno_min_cwnd(const struct sock *sk); 726 extern struct tcp_congestion_ops tcp_reno; 727 728 static inline void tcp_set_ca_state(struct sock *sk, const u8 ca_state) 729 { 730 struct inet_connection_sock *icsk = inet_csk(sk); 731 732 if (icsk->icsk_ca_ops->set_state) 733 icsk->icsk_ca_ops->set_state(sk, ca_state); 734 icsk->icsk_ca_state = ca_state; 735 } 736 737 static inline void tcp_ca_event(struct sock *sk, const enum tcp_ca_event event) 738 { 739 const struct inet_connection_sock *icsk = inet_csk(sk); 740 741 if (icsk->icsk_ca_ops->cwnd_event) 742 icsk->icsk_ca_ops->cwnd_event(sk, event); 743 } 744 745 /* These functions determine how the current flow behaves in respect of SACK 746 * handling. SACK is negotiated with the peer, and therefore it can vary 747 * between different flows. 748 * 749 * tcp_is_sack - SACK enabled 750 * tcp_is_reno - No SACK 751 * tcp_is_fack - FACK enabled, implies SACK enabled 752 */ 753 static inline int tcp_is_sack(const struct tcp_sock *tp) 754 { 755 return tp->rx_opt.sack_ok; 756 } 757 758 static inline int tcp_is_reno(const struct tcp_sock *tp) 759 { 760 return !tcp_is_sack(tp); 761 } 762 763 static inline int tcp_is_fack(const struct tcp_sock *tp) 764 { 765 return tp->rx_opt.sack_ok & 2; 766 } 767 768 static inline void tcp_enable_fack(struct tcp_sock *tp) 769 { 770 tp->rx_opt.sack_ok |= 2; 771 } 772 773 static inline unsigned int tcp_left_out(const struct tcp_sock *tp) 774 { 775 return tp->sacked_out + tp->lost_out; 776 } 777 778 /* This determines how many packets are "in the network" to the best 779 * of our knowledge. In many cases it is conservative, but where 780 * detailed information is available from the receiver (via SACK 781 * blocks etc.) we can make more aggressive calculations. 782 * 783 * Use this for decisions involving congestion control, use just 784 * tp->packets_out to determine if the send queue is empty or not. 785 * 786 * Read this equation as: 787 * 788 * "Packets sent once on transmission queue" MINUS 789 * "Packets left network, but not honestly ACKed yet" PLUS 790 * "Packets fast retransmitted" 791 */ 792 static inline unsigned int tcp_packets_in_flight(const struct tcp_sock *tp) 793 { 794 return tp->packets_out - tcp_left_out(tp) + tp->retrans_out; 795 } 796 797 #define TCP_INFINITE_SSTHRESH 0x7fffffff 798 799 static inline bool tcp_in_initial_slowstart(const struct tcp_sock *tp) 800 { 801 return tp->snd_ssthresh >= TCP_INFINITE_SSTHRESH; 802 } 803 804 /* If cwnd > ssthresh, we may raise ssthresh to be half-way to cwnd. 805 * The exception is rate halving phase, when cwnd is decreasing towards 806 * ssthresh. 807 */ 808 static inline __u32 tcp_current_ssthresh(const struct sock *sk) 809 { 810 const struct tcp_sock *tp = tcp_sk(sk); 811 if ((1 << inet_csk(sk)->icsk_ca_state) & (TCPF_CA_CWR | TCPF_CA_Recovery)) 812 return tp->snd_ssthresh; 813 else 814 return max(tp->snd_ssthresh, 815 ((tp->snd_cwnd >> 1) + 816 (tp->snd_cwnd >> 2))); 817 } 818 819 /* Use define here intentionally to get WARN_ON location shown at the caller */ 820 #define tcp_verify_left_out(tp) WARN_ON(tcp_left_out(tp) > tp->packets_out) 821 822 extern void tcp_enter_cwr(struct sock *sk, const int set_ssthresh); 823 extern __u32 tcp_init_cwnd(struct tcp_sock *tp, struct dst_entry *dst); 824 825 /* Slow start with delack produces 3 packets of burst, so that 826 * it is safe "de facto". This will be the default - same as 827 * the default reordering threshold - but if reordering increases, 828 * we must be able to allow cwnd to burst at least this much in order 829 * to not pull it back when holes are filled. 830 */ 831 static __inline__ __u32 tcp_max_burst(const struct tcp_sock *tp) 832 { 833 return tp->reordering; 834 } 835 836 /* Returns end sequence number of the receiver's advertised window */ 837 static inline u32 tcp_wnd_end(const struct tcp_sock *tp) 838 { 839 return tp->snd_una + tp->snd_wnd; 840 } 841 extern int tcp_is_cwnd_limited(const struct sock *sk, u32 in_flight); 842 843 static inline void tcp_minshall_update(struct tcp_sock *tp, unsigned int mss, 844 const struct sk_buff *skb) 845 { 846 if (skb->len < mss) 847 tp->snd_sml = TCP_SKB_CB(skb)->end_seq; 848 } 849 850 static inline void tcp_check_probe_timer(struct sock *sk) 851 { 852 struct tcp_sock *tp = tcp_sk(sk); 853 const struct inet_connection_sock *icsk = inet_csk(sk); 854 855 if (!tp->packets_out && !icsk->icsk_pending) 856 inet_csk_reset_xmit_timer(sk, ICSK_TIME_PROBE0, 857 icsk->icsk_rto, TCP_RTO_MAX); 858 } 859 860 static inline void tcp_push_pending_frames(struct sock *sk) 861 { 862 struct tcp_sock *tp = tcp_sk(sk); 863 864 __tcp_push_pending_frames(sk, tcp_current_mss(sk), tp->nonagle); 865 } 866 867 static inline void tcp_init_wl(struct tcp_sock *tp, u32 seq) 868 { 869 tp->snd_wl1 = seq; 870 } 871 872 static inline void tcp_update_wl(struct tcp_sock *tp, u32 seq) 873 { 874 tp->snd_wl1 = seq; 875 } 876 877 /* 878 * Calculate(/check) TCP checksum 879 */ 880 static inline __sum16 tcp_v4_check(int len, __be32 saddr, 881 __be32 daddr, __wsum base) 882 { 883 return csum_tcpudp_magic(saddr,daddr,len,IPPROTO_TCP,base); 884 } 885 886 static inline __sum16 __tcp_checksum_complete(struct sk_buff *skb) 887 { 888 return __skb_checksum_complete(skb); 889 } 890 891 static inline int tcp_checksum_complete(struct sk_buff *skb) 892 { 893 return !skb_csum_unnecessary(skb) && 894 __tcp_checksum_complete(skb); 895 } 896 897 /* Prequeue for VJ style copy to user, combined with checksumming. */ 898 899 static inline void tcp_prequeue_init(struct tcp_sock *tp) 900 { 901 tp->ucopy.task = NULL; 902 tp->ucopy.len = 0; 903 tp->ucopy.memory = 0; 904 skb_queue_head_init(&tp->ucopy.prequeue); 905 #ifdef CONFIG_NET_DMA 906 tp->ucopy.dma_chan = NULL; 907 tp->ucopy.wakeup = 0; 908 tp->ucopy.pinned_list = NULL; 909 tp->ucopy.dma_cookie = 0; 910 #endif 911 } 912 913 /* Packet is added to VJ-style prequeue for processing in process 914 * context, if a reader task is waiting. Apparently, this exciting 915 * idea (VJ's mail "Re: query about TCP header on tcp-ip" of 07 Sep 93) 916 * failed somewhere. Latency? Burstiness? Well, at least now we will 917 * see, why it failed. 8)8) --ANK 918 * 919 * NOTE: is this not too big to inline? 920 */ 921 static inline int tcp_prequeue(struct sock *sk, struct sk_buff *skb) 922 { 923 struct tcp_sock *tp = tcp_sk(sk); 924 925 if (sysctl_tcp_low_latency || !tp->ucopy.task) 926 return 0; 927 928 __skb_queue_tail(&tp->ucopy.prequeue, skb); 929 tp->ucopy.memory += skb->truesize; 930 if (tp->ucopy.memory > sk->sk_rcvbuf) { 931 struct sk_buff *skb1; 932 933 BUG_ON(sock_owned_by_user(sk)); 934 935 while ((skb1 = __skb_dequeue(&tp->ucopy.prequeue)) != NULL) { 936 sk_backlog_rcv(sk, skb1); 937 NET_INC_STATS_BH(sock_net(sk), 938 LINUX_MIB_TCPPREQUEUEDROPPED); 939 } 940 941 tp->ucopy.memory = 0; 942 } else if (skb_queue_len(&tp->ucopy.prequeue) == 1) { 943 wake_up_interruptible_poll(sk->sk_sleep, 944 POLLIN | POLLRDNORM | POLLRDBAND); 945 if (!inet_csk_ack_scheduled(sk)) 946 inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK, 947 (3 * tcp_rto_min(sk)) / 4, 948 TCP_RTO_MAX); 949 } 950 return 1; 951 } 952 953 954 #undef STATE_TRACE 955 956 #ifdef STATE_TRACE 957 static const char *statename[]={ 958 "Unused","Established","Syn Sent","Syn Recv", 959 "Fin Wait 1","Fin Wait 2","Time Wait", "Close", 960 "Close Wait","Last ACK","Listen","Closing" 961 }; 962 #endif 963 extern void tcp_set_state(struct sock *sk, int state); 964 965 extern void tcp_done(struct sock *sk); 966 967 static inline void tcp_sack_reset(struct tcp_options_received *rx_opt) 968 { 969 rx_opt->dsack = 0; 970 rx_opt->num_sacks = 0; 971 } 972 973 /* Determine a window scaling and initial window to offer. */ 974 extern void tcp_select_initial_window(int __space, __u32 mss, 975 __u32 *rcv_wnd, __u32 *window_clamp, 976 int wscale_ok, __u8 *rcv_wscale); 977 978 static inline int tcp_win_from_space(int space) 979 { 980 return sysctl_tcp_adv_win_scale<=0 ? 981 (space>>(-sysctl_tcp_adv_win_scale)) : 982 space - (space>>sysctl_tcp_adv_win_scale); 983 } 984 985 /* Note: caller must be prepared to deal with negative returns */ 986 static inline int tcp_space(const struct sock *sk) 987 { 988 return tcp_win_from_space(sk->sk_rcvbuf - 989 atomic_read(&sk->sk_rmem_alloc)); 990 } 991 992 static inline int tcp_full_space(const struct sock *sk) 993 { 994 return tcp_win_from_space(sk->sk_rcvbuf); 995 } 996 997 static inline void tcp_openreq_init(struct request_sock *req, 998 struct tcp_options_received *rx_opt, 999 struct sk_buff *skb) 1000 { 1001 struct inet_request_sock *ireq = inet_rsk(req); 1002 1003 req->rcv_wnd = 0; /* So that tcp_send_synack() knows! */ 1004 req->cookie_ts = 0; 1005 tcp_rsk(req)->rcv_isn = TCP_SKB_CB(skb)->seq; 1006 req->mss = rx_opt->mss_clamp; 1007 req->ts_recent = rx_opt->saw_tstamp ? rx_opt->rcv_tsval : 0; 1008 ireq->tstamp_ok = rx_opt->tstamp_ok; 1009 ireq->sack_ok = rx_opt->sack_ok; 1010 ireq->snd_wscale = rx_opt->snd_wscale; 1011 ireq->wscale_ok = rx_opt->wscale_ok; 1012 ireq->acked = 0; 1013 ireq->ecn_ok = 0; 1014 ireq->rmt_port = tcp_hdr(skb)->source; 1015 ireq->loc_port = tcp_hdr(skb)->dest; 1016 } 1017 1018 extern void tcp_enter_memory_pressure(struct sock *sk); 1019 1020 static inline int keepalive_intvl_when(const struct tcp_sock *tp) 1021 { 1022 return tp->keepalive_intvl ? : sysctl_tcp_keepalive_intvl; 1023 } 1024 1025 static inline int keepalive_time_when(const struct tcp_sock *tp) 1026 { 1027 return tp->keepalive_time ? : sysctl_tcp_keepalive_time; 1028 } 1029 1030 static inline int keepalive_probes(const struct tcp_sock *tp) 1031 { 1032 return tp->keepalive_probes ? : sysctl_tcp_keepalive_probes; 1033 } 1034 1035 static inline int tcp_fin_time(const struct sock *sk) 1036 { 1037 int fin_timeout = tcp_sk(sk)->linger2 ? : sysctl_tcp_fin_timeout; 1038 const int rto = inet_csk(sk)->icsk_rto; 1039 1040 if (fin_timeout < (rto << 2) - (rto >> 1)) 1041 fin_timeout = (rto << 2) - (rto >> 1); 1042 1043 return fin_timeout; 1044 } 1045 1046 static inline int tcp_paws_check(const struct tcp_options_received *rx_opt, 1047 int paws_win) 1048 { 1049 if ((s32)(rx_opt->ts_recent - rx_opt->rcv_tsval) <= paws_win) 1050 return 1; 1051 if (unlikely(get_seconds() >= rx_opt->ts_recent_stamp + TCP_PAWS_24DAYS)) 1052 return 1; 1053 1054 return 0; 1055 } 1056 1057 static inline int tcp_paws_reject(const struct tcp_options_received *rx_opt, 1058 int rst) 1059 { 1060 if (tcp_paws_check(rx_opt, 0)) 1061 return 0; 1062 1063 /* RST segments are not recommended to carry timestamp, 1064 and, if they do, it is recommended to ignore PAWS because 1065 "their cleanup function should take precedence over timestamps." 1066 Certainly, it is mistake. It is necessary to understand the reasons 1067 of this constraint to relax it: if peer reboots, clock may go 1068 out-of-sync and half-open connections will not be reset. 1069 Actually, the problem would be not existing if all 1070 the implementations followed draft about maintaining clock 1071 via reboots. Linux-2.2 DOES NOT! 1072 1073 However, we can relax time bounds for RST segments to MSL. 1074 */ 1075 if (rst && get_seconds() >= rx_opt->ts_recent_stamp + TCP_PAWS_MSL) 1076 return 0; 1077 return 1; 1078 } 1079 1080 #define TCP_CHECK_TIMER(sk) do { } while (0) 1081 1082 static inline void tcp_mib_init(struct net *net) 1083 { 1084 /* See RFC 2012 */ 1085 TCP_ADD_STATS_USER(net, TCP_MIB_RTOALGORITHM, 1); 1086 TCP_ADD_STATS_USER(net, TCP_MIB_RTOMIN, TCP_RTO_MIN*1000/HZ); 1087 TCP_ADD_STATS_USER(net, TCP_MIB_RTOMAX, TCP_RTO_MAX*1000/HZ); 1088 TCP_ADD_STATS_USER(net, TCP_MIB_MAXCONN, -1); 1089 } 1090 1091 /* from STCP */ 1092 static inline void tcp_clear_retrans_hints_partial(struct tcp_sock *tp) 1093 { 1094 tp->lost_skb_hint = NULL; 1095 tp->scoreboard_skb_hint = NULL; 1096 } 1097 1098 static inline void tcp_clear_all_retrans_hints(struct tcp_sock *tp) 1099 { 1100 tcp_clear_retrans_hints_partial(tp); 1101 tp->retransmit_skb_hint = NULL; 1102 } 1103 1104 /* MD5 Signature */ 1105 struct crypto_hash; 1106 1107 /* - key database */ 1108 struct tcp_md5sig_key { 1109 u8 *key; 1110 u8 keylen; 1111 }; 1112 1113 struct tcp4_md5sig_key { 1114 struct tcp_md5sig_key base; 1115 __be32 addr; 1116 }; 1117 1118 struct tcp6_md5sig_key { 1119 struct tcp_md5sig_key base; 1120 #if 0 1121 u32 scope_id; /* XXX */ 1122 #endif 1123 struct in6_addr addr; 1124 }; 1125 1126 /* - sock block */ 1127 struct tcp_md5sig_info { 1128 struct tcp4_md5sig_key *keys4; 1129 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) 1130 struct tcp6_md5sig_key *keys6; 1131 u32 entries6; 1132 u32 alloced6; 1133 #endif 1134 u32 entries4; 1135 u32 alloced4; 1136 }; 1137 1138 /* - pseudo header */ 1139 struct tcp4_pseudohdr { 1140 __be32 saddr; 1141 __be32 daddr; 1142 __u8 pad; 1143 __u8 protocol; 1144 __be16 len; 1145 }; 1146 1147 struct tcp6_pseudohdr { 1148 struct in6_addr saddr; 1149 struct in6_addr daddr; 1150 __be32 len; 1151 __be32 protocol; /* including padding */ 1152 }; 1153 1154 union tcp_md5sum_block { 1155 struct tcp4_pseudohdr ip4; 1156 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) 1157 struct tcp6_pseudohdr ip6; 1158 #endif 1159 }; 1160 1161 /* - pool: digest algorithm, hash description and scratch buffer */ 1162 struct tcp_md5sig_pool { 1163 struct hash_desc md5_desc; 1164 union tcp_md5sum_block md5_blk; 1165 }; 1166 1167 #define TCP_MD5SIG_MAXKEYS (~(u32)0) /* really?! */ 1168 1169 /* - functions */ 1170 extern int tcp_v4_md5_hash_skb(char *md5_hash, 1171 struct tcp_md5sig_key *key, 1172 struct sock *sk, 1173 struct request_sock *req, 1174 struct sk_buff *skb); 1175 1176 extern struct tcp_md5sig_key *tcp_v4_md5_lookup(struct sock *sk, 1177 struct sock *addr_sk); 1178 1179 extern int tcp_v4_md5_do_add(struct sock *sk, 1180 __be32 addr, 1181 u8 *newkey, 1182 u8 newkeylen); 1183 1184 extern int tcp_v4_md5_do_del(struct sock *sk, 1185 __be32 addr); 1186 1187 #ifdef CONFIG_TCP_MD5SIG 1188 #define tcp_twsk_md5_key(twsk) ((twsk)->tw_md5_keylen ? \ 1189 &(struct tcp_md5sig_key) { \ 1190 .key = (twsk)->tw_md5_key, \ 1191 .keylen = (twsk)->tw_md5_keylen, \ 1192 } : NULL) 1193 #else 1194 #define tcp_twsk_md5_key(twsk) NULL 1195 #endif 1196 1197 extern struct tcp_md5sig_pool **tcp_alloc_md5sig_pool(struct sock *); 1198 extern void tcp_free_md5sig_pool(void); 1199 1200 extern struct tcp_md5sig_pool *__tcp_get_md5sig_pool(int cpu); 1201 extern void __tcp_put_md5sig_pool(void); 1202 extern int tcp_md5_hash_header(struct tcp_md5sig_pool *, struct tcphdr *); 1203 extern int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *, struct sk_buff *, 1204 unsigned header_len); 1205 extern int tcp_md5_hash_key(struct tcp_md5sig_pool *hp, 1206 struct tcp_md5sig_key *key); 1207 1208 static inline 1209 struct tcp_md5sig_pool *tcp_get_md5sig_pool(void) 1210 { 1211 int cpu = get_cpu(); 1212 struct tcp_md5sig_pool *ret = __tcp_get_md5sig_pool(cpu); 1213 if (!ret) 1214 put_cpu(); 1215 return ret; 1216 } 1217 1218 static inline void tcp_put_md5sig_pool(void) 1219 { 1220 __tcp_put_md5sig_pool(); 1221 put_cpu(); 1222 } 1223 1224 /* write queue abstraction */ 1225 static inline void tcp_write_queue_purge(struct sock *sk) 1226 { 1227 struct sk_buff *skb; 1228 1229 while ((skb = __skb_dequeue(&sk->sk_write_queue)) != NULL) 1230 sk_wmem_free_skb(sk, skb); 1231 sk_mem_reclaim(sk); 1232 tcp_clear_all_retrans_hints(tcp_sk(sk)); 1233 } 1234 1235 static inline struct sk_buff *tcp_write_queue_head(struct sock *sk) 1236 { 1237 return skb_peek(&sk->sk_write_queue); 1238 } 1239 1240 static inline struct sk_buff *tcp_write_queue_tail(struct sock *sk) 1241 { 1242 return skb_peek_tail(&sk->sk_write_queue); 1243 } 1244 1245 static inline struct sk_buff *tcp_write_queue_next(struct sock *sk, struct sk_buff *skb) 1246 { 1247 return skb_queue_next(&sk->sk_write_queue, skb); 1248 } 1249 1250 static inline struct sk_buff *tcp_write_queue_prev(struct sock *sk, struct sk_buff *skb) 1251 { 1252 return skb_queue_prev(&sk->sk_write_queue, skb); 1253 } 1254 1255 #define tcp_for_write_queue(skb, sk) \ 1256 skb_queue_walk(&(sk)->sk_write_queue, skb) 1257 1258 #define tcp_for_write_queue_from(skb, sk) \ 1259 skb_queue_walk_from(&(sk)->sk_write_queue, skb) 1260 1261 #define tcp_for_write_queue_from_safe(skb, tmp, sk) \ 1262 skb_queue_walk_from_safe(&(sk)->sk_write_queue, skb, tmp) 1263 1264 static inline struct sk_buff *tcp_send_head(struct sock *sk) 1265 { 1266 return sk->sk_send_head; 1267 } 1268 1269 static inline bool tcp_skb_is_last(const struct sock *sk, 1270 const struct sk_buff *skb) 1271 { 1272 return skb_queue_is_last(&sk->sk_write_queue, skb); 1273 } 1274 1275 static inline void tcp_advance_send_head(struct sock *sk, struct sk_buff *skb) 1276 { 1277 if (tcp_skb_is_last(sk, skb)) 1278 sk->sk_send_head = NULL; 1279 else 1280 sk->sk_send_head = tcp_write_queue_next(sk, skb); 1281 } 1282 1283 static inline void tcp_check_send_head(struct sock *sk, struct sk_buff *skb_unlinked) 1284 { 1285 if (sk->sk_send_head == skb_unlinked) 1286 sk->sk_send_head = NULL; 1287 } 1288 1289 static inline void tcp_init_send_head(struct sock *sk) 1290 { 1291 sk->sk_send_head = NULL; 1292 } 1293 1294 static inline void __tcp_add_write_queue_tail(struct sock *sk, struct sk_buff *skb) 1295 { 1296 __skb_queue_tail(&sk->sk_write_queue, skb); 1297 } 1298 1299 static inline void tcp_add_write_queue_tail(struct sock *sk, struct sk_buff *skb) 1300 { 1301 __tcp_add_write_queue_tail(sk, skb); 1302 1303 /* Queue it, remembering where we must start sending. */ 1304 if (sk->sk_send_head == NULL) { 1305 sk->sk_send_head = skb; 1306 1307 if (tcp_sk(sk)->highest_sack == NULL) 1308 tcp_sk(sk)->highest_sack = skb; 1309 } 1310 } 1311 1312 static inline void __tcp_add_write_queue_head(struct sock *sk, struct sk_buff *skb) 1313 { 1314 __skb_queue_head(&sk->sk_write_queue, skb); 1315 } 1316 1317 /* Insert buff after skb on the write queue of sk. */ 1318 static inline void tcp_insert_write_queue_after(struct sk_buff *skb, 1319 struct sk_buff *buff, 1320 struct sock *sk) 1321 { 1322 __skb_queue_after(&sk->sk_write_queue, skb, buff); 1323 } 1324 1325 /* Insert new before skb on the write queue of sk. */ 1326 static inline void tcp_insert_write_queue_before(struct sk_buff *new, 1327 struct sk_buff *skb, 1328 struct sock *sk) 1329 { 1330 __skb_queue_before(&sk->sk_write_queue, skb, new); 1331 1332 if (sk->sk_send_head == skb) 1333 sk->sk_send_head = new; 1334 } 1335 1336 static inline void tcp_unlink_write_queue(struct sk_buff *skb, struct sock *sk) 1337 { 1338 __skb_unlink(skb, &sk->sk_write_queue); 1339 } 1340 1341 static inline int tcp_write_queue_empty(struct sock *sk) 1342 { 1343 return skb_queue_empty(&sk->sk_write_queue); 1344 } 1345 1346 /* Start sequence of the highest skb with SACKed bit, valid only if 1347 * sacked > 0 or when the caller has ensured validity by itself. 1348 */ 1349 static inline u32 tcp_highest_sack_seq(struct tcp_sock *tp) 1350 { 1351 if (!tp->sacked_out) 1352 return tp->snd_una; 1353 1354 if (tp->highest_sack == NULL) 1355 return tp->snd_nxt; 1356 1357 return TCP_SKB_CB(tp->highest_sack)->seq; 1358 } 1359 1360 static inline void tcp_advance_highest_sack(struct sock *sk, struct sk_buff *skb) 1361 { 1362 tcp_sk(sk)->highest_sack = tcp_skb_is_last(sk, skb) ? NULL : 1363 tcp_write_queue_next(sk, skb); 1364 } 1365 1366 static inline struct sk_buff *tcp_highest_sack(struct sock *sk) 1367 { 1368 return tcp_sk(sk)->highest_sack; 1369 } 1370 1371 static inline void tcp_highest_sack_reset(struct sock *sk) 1372 { 1373 tcp_sk(sk)->highest_sack = tcp_write_queue_head(sk); 1374 } 1375 1376 /* Called when old skb is about to be deleted (to be combined with new skb) */ 1377 static inline void tcp_highest_sack_combine(struct sock *sk, 1378 struct sk_buff *old, 1379 struct sk_buff *new) 1380 { 1381 if (tcp_sk(sk)->sacked_out && (old == tcp_sk(sk)->highest_sack)) 1382 tcp_sk(sk)->highest_sack = new; 1383 } 1384 1385 /* /proc */ 1386 enum tcp_seq_states { 1387 TCP_SEQ_STATE_LISTENING, 1388 TCP_SEQ_STATE_OPENREQ, 1389 TCP_SEQ_STATE_ESTABLISHED, 1390 TCP_SEQ_STATE_TIME_WAIT, 1391 }; 1392 1393 struct tcp_seq_afinfo { 1394 char *name; 1395 sa_family_t family; 1396 struct file_operations seq_fops; 1397 struct seq_operations seq_ops; 1398 }; 1399 1400 struct tcp_iter_state { 1401 struct seq_net_private p; 1402 sa_family_t family; 1403 enum tcp_seq_states state; 1404 struct sock *syn_wait_sk; 1405 int bucket, sbucket, num, uid; 1406 }; 1407 1408 extern int tcp_proc_register(struct net *net, struct tcp_seq_afinfo *afinfo); 1409 extern void tcp_proc_unregister(struct net *net, struct tcp_seq_afinfo *afinfo); 1410 1411 extern struct request_sock_ops tcp_request_sock_ops; 1412 extern struct request_sock_ops tcp6_request_sock_ops; 1413 1414 extern void tcp_v4_destroy_sock(struct sock *sk); 1415 1416 extern int tcp_v4_gso_send_check(struct sk_buff *skb); 1417 extern struct sk_buff *tcp_tso_segment(struct sk_buff *skb, int features); 1418 extern struct sk_buff **tcp_gro_receive(struct sk_buff **head, 1419 struct sk_buff *skb); 1420 extern struct sk_buff **tcp4_gro_receive(struct sk_buff **head, 1421 struct sk_buff *skb); 1422 extern int tcp_gro_complete(struct sk_buff *skb); 1423 extern int tcp4_gro_complete(struct sk_buff *skb); 1424 1425 #ifdef CONFIG_PROC_FS 1426 extern int tcp4_proc_init(void); 1427 extern void tcp4_proc_exit(void); 1428 #endif 1429 1430 /* TCP af-specific functions */ 1431 struct tcp_sock_af_ops { 1432 #ifdef CONFIG_TCP_MD5SIG 1433 struct tcp_md5sig_key *(*md5_lookup) (struct sock *sk, 1434 struct sock *addr_sk); 1435 int (*calc_md5_hash) (char *location, 1436 struct tcp_md5sig_key *md5, 1437 struct sock *sk, 1438 struct request_sock *req, 1439 struct sk_buff *skb); 1440 int (*md5_add) (struct sock *sk, 1441 struct sock *addr_sk, 1442 u8 *newkey, 1443 u8 len); 1444 int (*md5_parse) (struct sock *sk, 1445 char __user *optval, 1446 int optlen); 1447 #endif 1448 }; 1449 1450 struct tcp_request_sock_ops { 1451 #ifdef CONFIG_TCP_MD5SIG 1452 struct tcp_md5sig_key *(*md5_lookup) (struct sock *sk, 1453 struct request_sock *req); 1454 int (*calc_md5_hash) (char *location, 1455 struct tcp_md5sig_key *md5, 1456 struct sock *sk, 1457 struct request_sock *req, 1458 struct sk_buff *skb); 1459 #endif 1460 }; 1461 1462 /* Using SHA1 for now, define some constants. 1463 */ 1464 #define COOKIE_DIGEST_WORDS (SHA_DIGEST_WORDS) 1465 #define COOKIE_MESSAGE_WORDS (SHA_MESSAGE_BYTES / 4) 1466 #define COOKIE_WORKSPACE_WORDS (COOKIE_DIGEST_WORDS + COOKIE_MESSAGE_WORDS) 1467 1468 extern int tcp_cookie_generator(u32 *bakery); 1469 1470 /** 1471 * struct tcp_cookie_values - each socket needs extra space for the 1472 * cookies, together with (optional) space for any SYN data. 1473 * 1474 * A tcp_sock contains a pointer to the current value, and this is 1475 * cloned to the tcp_timewait_sock. 1476 * 1477 * @cookie_pair: variable data from the option exchange. 1478 * 1479 * @cookie_desired: user specified tcpct_cookie_desired. Zero 1480 * indicates default (sysctl_tcp_cookie_size). 1481 * After cookie sent, remembers size of cookie. 1482 * Range 0, TCP_COOKIE_MIN to TCP_COOKIE_MAX. 1483 * 1484 * @s_data_desired: user specified tcpct_s_data_desired. When the 1485 * constant payload is specified (@s_data_constant), 1486 * holds its length instead. 1487 * Range 0 to TCP_MSS_DESIRED. 1488 * 1489 * @s_data_payload: constant data that is to be included in the 1490 * payload of SYN or SYNACK segments when the 1491 * cookie option is present. 1492 */ 1493 struct tcp_cookie_values { 1494 struct kref kref; 1495 u8 cookie_pair[TCP_COOKIE_PAIR_SIZE]; 1496 u8 cookie_pair_size; 1497 u8 cookie_desired; 1498 u16 s_data_desired:11, 1499 s_data_constant:1, 1500 s_data_in:1, 1501 s_data_out:1, 1502 s_data_unused:2; 1503 u8 s_data_payload[0]; 1504 }; 1505 1506 static inline void tcp_cookie_values_release(struct kref *kref) 1507 { 1508 kfree(container_of(kref, struct tcp_cookie_values, kref)); 1509 } 1510 1511 /* The length of constant payload data. Note that s_data_desired is 1512 * overloaded, depending on s_data_constant: either the length of constant 1513 * data (returned here) or the limit on variable data. 1514 */ 1515 static inline int tcp_s_data_size(const struct tcp_sock *tp) 1516 { 1517 return (tp->cookie_values != NULL && tp->cookie_values->s_data_constant) 1518 ? tp->cookie_values->s_data_desired 1519 : 0; 1520 } 1521 1522 /** 1523 * struct tcp_extend_values - tcp_ipv?.c to tcp_output.c workspace. 1524 * 1525 * As tcp_request_sock has already been extended in other places, the 1526 * only remaining method is to pass stack values along as function 1527 * parameters. These parameters are not needed after sending SYNACK. 1528 * 1529 * @cookie_bakery: cryptographic secret and message workspace. 1530 * 1531 * @cookie_plus: bytes in authenticator/cookie option, copied from 1532 * struct tcp_options_received (above). 1533 */ 1534 struct tcp_extend_values { 1535 struct request_values rv; 1536 u32 cookie_bakery[COOKIE_WORKSPACE_WORDS]; 1537 u8 cookie_plus:6, 1538 cookie_out_never:1, 1539 cookie_in_always:1; 1540 }; 1541 1542 static inline struct tcp_extend_values *tcp_xv(struct request_values *rvp) 1543 { 1544 return (struct tcp_extend_values *)rvp; 1545 } 1546 1547 extern void tcp_v4_init(void); 1548 extern void tcp_init(void); 1549 1550 #endif /* _TCP_H */ 1551