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 protocol. 7 * 8 * Version: @(#)tcp.h 1.0.2 04/28/93 9 * 10 * Author: Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG> 11 * 12 * This program is free software; you can redistribute it and/or 13 * modify it under the terms of the GNU General Public License 14 * as published by the Free Software Foundation; either version 15 * 2 of the License, or (at your option) any later version. 16 */ 17#ifndef _LINUX_TCP_H 18#define _LINUX_TCP_H 19 20#include <linux/types.h> 21#include <asm/byteorder.h> 22#include <linux/socket.h> 23 24struct tcphdr { 25 __be16 source; 26 __be16 dest; 27 __be32 seq; 28 __be32 ack_seq; 29#if defined(__LITTLE_ENDIAN_BITFIELD) 30 __u16 res1:4, 31 doff:4, 32 fin:1, 33 syn:1, 34 rst:1, 35 psh:1, 36 ack:1, 37 urg:1, 38 ece:1, 39 cwr:1; 40#elif defined(__BIG_ENDIAN_BITFIELD) 41 __u16 doff:4, 42 res1:4, 43 cwr:1, 44 ece:1, 45 urg:1, 46 ack:1, 47 psh:1, 48 rst:1, 49 syn:1, 50 fin:1; 51#else 52#error "Adjust your <asm/byteorder.h> defines" 53#endif 54 __be16 window; 55 __sum16 check; 56 __be16 urg_ptr; 57}; 58 59/* 60 * The union cast uses a gcc extension to avoid aliasing problems 61 * (union is compatible to any of its members) 62 * This means this part of the code is -fstrict-aliasing safe now. 63 */ 64union tcp_word_hdr { 65 struct tcphdr hdr; 66 __be32 words[5]; 67}; 68 69#define tcp_flag_word(tp) ( ((union tcp_word_hdr *)(tp))->words [3]) 70 71enum { 72 TCP_FLAG_CWR = __cpu_to_be32(0x00800000), 73 TCP_FLAG_ECE = __cpu_to_be32(0x00400000), 74 TCP_FLAG_URG = __cpu_to_be32(0x00200000), 75 TCP_FLAG_ACK = __cpu_to_be32(0x00100000), 76 TCP_FLAG_PSH = __cpu_to_be32(0x00080000), 77 TCP_FLAG_RST = __cpu_to_be32(0x00040000), 78 TCP_FLAG_SYN = __cpu_to_be32(0x00020000), 79 TCP_FLAG_FIN = __cpu_to_be32(0x00010000), 80 TCP_RESERVED_BITS = __cpu_to_be32(0x0F000000), 81 TCP_DATA_OFFSET = __cpu_to_be32(0xF0000000) 82}; 83 84/* 85 * TCP general constants 86 */ 87#define TCP_MSS_DEFAULT 536U /* IPv4 (RFC1122, RFC2581) */ 88#define TCP_MSS_DESIRED 1220U /* IPv6 (tunneled), EDNS0 (RFC3226) */ 89 90/* TCP socket options */ 91#define TCP_NODELAY 1 /* Turn off Nagle's algorithm. */ 92#define TCP_MAXSEG 2 /* Limit MSS */ 93#define TCP_CORK 3 /* Never send partially complete segments */ 94#define TCP_KEEPIDLE 4 /* Start keeplives after this period */ 95#define TCP_KEEPINTVL 5 /* Interval between keepalives */ 96#define TCP_KEEPCNT 6 /* Number of keepalives before death */ 97#define TCP_SYNCNT 7 /* Number of SYN retransmits */ 98#define TCP_LINGER2 8 /* Life time of orphaned FIN-WAIT-2 state */ 99#define TCP_DEFER_ACCEPT 9 /* Wake up listener only when data arrive */ 100#define TCP_WINDOW_CLAMP 10 /* Bound advertised window */ 101#define TCP_INFO 11 /* Information about this connection. */ 102#define TCP_QUICKACK 12 /* Block/reenable quick acks */ 103#define TCP_CONGESTION 13 /* Congestion control algorithm */ 104#define TCP_MD5SIG 14 /* TCP MD5 Signature (RFC2385) */ 105#define TCP_COOKIE_TRANSACTIONS 15 /* TCP Cookie Transactions */ 106#define TCP_THIN_LINEAR_TIMEOUTS 16 /* Use linear timeouts for thin streams*/ 107#define TCP_THIN_DUPACK 17 /* Fast retrans. after 1 dupack */ 108 109/* for TCP_INFO socket option */ 110#define TCPI_OPT_TIMESTAMPS 1 111#define TCPI_OPT_SACK 2 112#define TCPI_OPT_WSCALE 4 113#define TCPI_OPT_ECN 8 114 115enum tcp_ca_state { 116 TCP_CA_Open = 0, 117#define TCPF_CA_Open (1<<TCP_CA_Open) 118 TCP_CA_Disorder = 1, 119#define TCPF_CA_Disorder (1<<TCP_CA_Disorder) 120 TCP_CA_CWR = 2, 121#define TCPF_CA_CWR (1<<TCP_CA_CWR) 122 TCP_CA_Recovery = 3, 123#define TCPF_CA_Recovery (1<<TCP_CA_Recovery) 124 TCP_CA_Loss = 4 125#define TCPF_CA_Loss (1<<TCP_CA_Loss) 126}; 127 128struct tcp_info { 129 __u8 tcpi_state; 130 __u8 tcpi_ca_state; 131 __u8 tcpi_retransmits; 132 __u8 tcpi_probes; 133 __u8 tcpi_backoff; 134 __u8 tcpi_options; 135 __u8 tcpi_snd_wscale : 4, tcpi_rcv_wscale : 4; 136 137 __u32 tcpi_rto; 138 __u32 tcpi_ato; 139 __u32 tcpi_snd_mss; 140 __u32 tcpi_rcv_mss; 141 142 __u32 tcpi_unacked; 143 __u32 tcpi_sacked; 144 __u32 tcpi_lost; 145 __u32 tcpi_retrans; 146 __u32 tcpi_fackets; 147 148 /* Times. */ 149 __u32 tcpi_last_data_sent; 150 __u32 tcpi_last_ack_sent; /* Not remembered, sorry. */ 151 __u32 tcpi_last_data_recv; 152 __u32 tcpi_last_ack_recv; 153 154 /* Metrics. */ 155 __u32 tcpi_pmtu; 156 __u32 tcpi_rcv_ssthresh; 157 __u32 tcpi_rtt; 158 __u32 tcpi_rttvar; 159 __u32 tcpi_snd_ssthresh; 160 __u32 tcpi_snd_cwnd; 161 __u32 tcpi_advmss; 162 __u32 tcpi_reordering; 163 164 __u32 tcpi_rcv_rtt; 165 __u32 tcpi_rcv_space; 166 167 __u32 tcpi_total_retrans; 168}; 169 170/* for TCP_MD5SIG socket option */ 171#define TCP_MD5SIG_MAXKEYLEN 80 172 173struct tcp_md5sig { 174 struct __kernel_sockaddr_storage tcpm_addr; /* address associated */ 175 __u16 __tcpm_pad1; /* zero */ 176 __u16 tcpm_keylen; /* key length */ 177 __u32 __tcpm_pad2; /* zero */ 178 __u8 tcpm_key[TCP_MD5SIG_MAXKEYLEN]; /* key (binary) */ 179}; 180 181/* for TCP_COOKIE_TRANSACTIONS (TCPCT) socket option */ 182#define TCP_COOKIE_MIN 8 /* 64-bits */ 183#define TCP_COOKIE_MAX 16 /* 128-bits */ 184#define TCP_COOKIE_PAIR_SIZE (2*TCP_COOKIE_MAX) 185 186/* Flags for both getsockopt and setsockopt */ 187#define TCP_COOKIE_IN_ALWAYS (1 << 0) /* Discard SYN without cookie */ 188#define TCP_COOKIE_OUT_NEVER (1 << 1) /* Prohibit outgoing cookies, 189 * supercedes everything. */ 190 191/* Flags for getsockopt */ 192#define TCP_S_DATA_IN (1 << 2) /* Was data received? */ 193#define TCP_S_DATA_OUT (1 << 3) /* Was data sent? */ 194 195/* TCP_COOKIE_TRANSACTIONS data */ 196struct tcp_cookie_transactions { 197 __u16 tcpct_flags; /* see above */ 198 __u8 __tcpct_pad1; /* zero */ 199 __u8 tcpct_cookie_desired; /* bytes */ 200 __u16 tcpct_s_data_desired; /* bytes of variable data */ 201 __u16 tcpct_used; /* bytes in value */ 202 __u8 tcpct_value[TCP_MSS_DEFAULT]; 203}; 204 205#ifdef __KERNEL__ 206 207#include <linux/skbuff.h> 208#include <linux/dmaengine.h> 209#include <net/sock.h> 210#include <net/inet_connection_sock.h> 211#include <net/inet_timewait_sock.h> 212 213static inline struct tcphdr *tcp_hdr(const struct sk_buff *skb) 214{ 215 return (struct tcphdr *)skb_transport_header(skb); 216} 217 218static inline unsigned int tcp_hdrlen(const struct sk_buff *skb) 219{ 220 return tcp_hdr(skb)->doff * 4; 221} 222 223static inline unsigned int tcp_optlen(const struct sk_buff *skb) 224{ 225 return (tcp_hdr(skb)->doff - 5) * 4; 226} 227 228/* This defines a selective acknowledgement block. */ 229struct tcp_sack_block_wire { 230 __be32 start_seq; 231 __be32 end_seq; 232}; 233 234struct tcp_sack_block { 235 u32 start_seq; 236 u32 end_seq; 237}; 238 239struct tcp_options_received { 240/* PAWS/RTTM data */ 241 long ts_recent_stamp;/* Time we stored ts_recent (for aging) */ 242 u32 ts_recent; /* Time stamp to echo next */ 243 u32 rcv_tsval; /* Time stamp value */ 244 u32 rcv_tsecr; /* Time stamp echo reply */ 245 u16 saw_tstamp : 1, /* Saw TIMESTAMP on last packet */ 246 tstamp_ok : 1, /* TIMESTAMP seen on SYN packet */ 247 dsack : 1, /* D-SACK is scheduled */ 248 wscale_ok : 1, /* Wscale seen on SYN packet */ 249 sack_ok : 4, /* SACK seen on SYN packet */ 250 snd_wscale : 4, /* Window scaling received from sender */ 251 rcv_wscale : 4; /* Window scaling to send to receiver */ 252 u8 cookie_plus:6, /* bytes in authenticator/cookie option */ 253 cookie_out_never:1, 254 cookie_in_always:1; 255 u8 num_sacks; /* Number of SACK blocks */ 256 u16 user_mss; /* mss requested by user in ioctl */ 257 u16 mss_clamp; /* Maximal mss, negotiated at connection setup */ 258}; 259 260static inline void tcp_clear_options(struct tcp_options_received *rx_opt) 261{ 262 rx_opt->tstamp_ok = rx_opt->sack_ok = 0; 263 rx_opt->wscale_ok = rx_opt->snd_wscale = 0; 264 rx_opt->cookie_plus = 0; 265} 266 267/* This is the max number of SACKS that we'll generate and process. It's safe 268 * to increase this, although since: 269 * size = TCPOLEN_SACK_BASE_ALIGNED (4) + n * TCPOLEN_SACK_PERBLOCK (8) 270 * only four options will fit in a standard TCP header */ 271#define TCP_NUM_SACKS 4 272 273struct tcp_cookie_values; 274struct tcp_request_sock_ops; 275 276struct tcp_request_sock { 277 struct inet_request_sock req; 278#ifdef CONFIG_TCP_MD5SIG 279 /* Only used by TCP MD5 Signature so far. */ 280 const struct tcp_request_sock_ops *af_specific; 281#endif 282 u32 rcv_isn; 283 u32 snt_isn; 284}; 285 286static inline struct tcp_request_sock *tcp_rsk(const struct request_sock *req) 287{ 288 return (struct tcp_request_sock *)req; 289} 290 291struct tcp_sock { 292 /* inet_connection_sock has to be the first member of tcp_sock */ 293 struct inet_connection_sock inet_conn; 294 u16 tcp_header_len; /* Bytes of tcp header to send */ 295 u16 xmit_size_goal_segs; /* Goal for segmenting output packets */ 296 297/* 298 * Header prediction flags 299 * 0x5?10 << 16 + snd_wnd in net byte order 300 */ 301 __be32 pred_flags; 302 303/* 304 * RFC793 variables by their proper names. This means you can 305 * read the code and the spec side by side (and laugh ...) 306 * See RFC793 and RFC1122. The RFC writes these in capitals. 307 */ 308 u32 rcv_nxt; /* What we want to receive next */ 309 u32 copied_seq; /* Head of yet unread data */ 310 u32 rcv_wup; /* rcv_nxt on last window update sent */ 311 u32 snd_nxt; /* Next sequence we send */ 312 313 u32 snd_una; /* First byte we want an ack for */ 314 u32 snd_sml; /* Last byte of the most recently transmitted small packet */ 315 u32 rcv_tstamp; /* timestamp of last received ACK (for keepalives) */ 316 u32 lsndtime; /* timestamp of last sent data packet (for restart window) */ 317 318 /* Data for direct copy to user */ 319 struct { 320 struct sk_buff_head prequeue; 321 struct task_struct *task; 322 struct iovec *iov; 323 int memory; 324 int len; 325#ifdef CONFIG_NET_DMA 326 /* members for async copy */ 327 struct dma_chan *dma_chan; 328 int wakeup; 329 struct dma_pinned_list *pinned_list; 330 dma_cookie_t dma_cookie; 331#endif 332 } ucopy; 333 334 u32 snd_wl1; /* Sequence for window update */ 335 u32 snd_wnd; /* The window we expect to receive */ 336 u32 max_window; /* Maximal window ever seen from peer */ 337 u32 mss_cache; /* Cached effective mss, not including SACKS */ 338 339 u32 window_clamp; /* Maximal window to advertise */ 340 u32 rcv_ssthresh; /* Current window clamp */ 341 342 u32 frto_highmark; /* snd_nxt when RTO occurred */ 343 u16 advmss; /* Advertised MSS */ 344 u8 frto_counter; /* Number of new acks after RTO */ 345 u8 nonagle : 4,/* Disable Nagle algorithm? */ 346 thin_lto : 1,/* Use linear timeouts for thin streams */ 347 thin_dupack : 1,/* Fast retransmit on first dupack */ 348 unused : 2; 349 350/* RTT measurement */ 351 u32 srtt; /* smoothed round trip time << 3 */ 352 u32 mdev; /* medium deviation */ 353 u32 mdev_max; /* maximal mdev for the last rtt period */ 354 u32 rttvar; /* smoothed mdev_max */ 355 u32 rtt_seq; /* sequence number to update rttvar */ 356 357 u32 packets_out; /* Packets which are "in flight" */ 358 u32 retrans_out; /* Retransmitted packets out */ 359 360 u16 urg_data; /* Saved octet of OOB data and control flags */ 361 u8 ecn_flags; /* ECN status bits. */ 362 u8 reordering; /* Packet reordering metric. */ 363 u32 snd_up; /* Urgent pointer */ 364 365 u8 keepalive_probes; /* num of allowed keep alive probes */ 366/* 367 * Options received (usually on last packet, some only on SYN packets). 368 */ 369 struct tcp_options_received rx_opt; 370 371/* 372 * Slow start and congestion control (see also Nagle, and Karn & Partridge) 373 */ 374 u32 snd_ssthresh; /* Slow start size threshold */ 375 u32 snd_cwnd; /* Sending congestion window */ 376 u32 snd_cwnd_cnt; /* Linear increase counter */ 377 u32 snd_cwnd_clamp; /* Do not allow snd_cwnd to grow above this */ 378 u32 snd_cwnd_used; 379 u32 snd_cwnd_stamp; 380 381 u32 rcv_wnd; /* Current receiver window */ 382 u32 write_seq; /* Tail(+1) of data held in tcp send buffer */ 383 u32 pushed_seq; /* Last pushed seq, required to talk to windows */ 384 u32 lost_out; /* Lost packets */ 385 u32 sacked_out; /* SACK'd packets */ 386 u32 fackets_out; /* FACK'd packets */ 387 u32 tso_deferred; 388 u32 bytes_acked; /* Appropriate Byte Counting - RFC3465 */ 389 390 /* from STCP, retrans queue hinting */ 391 struct sk_buff* lost_skb_hint; 392 struct sk_buff *scoreboard_skb_hint; 393 struct sk_buff *retransmit_skb_hint; 394 395 struct sk_buff_head out_of_order_queue; /* Out of order segments go here */ 396 397 /* SACKs data, these 2 need to be together (see tcp_build_and_update_options) */ 398 struct tcp_sack_block duplicate_sack[1]; /* D-SACK block */ 399 struct tcp_sack_block selective_acks[4]; /* The SACKS themselves*/ 400 401 struct tcp_sack_block recv_sack_cache[4]; 402 403 struct sk_buff *highest_sack; /* highest skb with SACK received 404 * (validity guaranteed only if 405 * sacked_out > 0) 406 */ 407 408 int lost_cnt_hint; 409 u32 retransmit_high; /* L-bits may be on up to this seqno */ 410 411 u32 lost_retrans_low; /* Sent seq after any rxmit (lowest) */ 412 413 u32 prior_ssthresh; /* ssthresh saved at recovery start */ 414 u32 high_seq; /* snd_nxt at onset of congestion */ 415 416 u32 retrans_stamp; /* Timestamp of the last retransmit, 417 * also used in SYN-SENT to remember stamp of 418 * the first SYN. */ 419 u32 undo_marker; /* tracking retrans started here. */ 420 int undo_retrans; /* number of undoable retransmissions. */ 421 u32 total_retrans; /* Total retransmits for entire connection */ 422 423 u32 urg_seq; /* Seq of received urgent pointer */ 424 unsigned int keepalive_time; /* time before keep alive takes place */ 425 unsigned int keepalive_intvl; /* time interval between keep alive probes */ 426 427 int linger2; 428 429/* Receiver side RTT estimation */ 430 struct { 431 u32 rtt; 432 u32 seq; 433 u32 time; 434 } rcv_rtt_est; 435 436/* Receiver queue space */ 437 struct { 438 int space; 439 u32 seq; 440 u32 time; 441 } rcvq_space; 442 443/* TCP-specific MTU probe information. */ 444 struct { 445 u32 probe_seq_start; 446 u32 probe_seq_end; 447 } mtu_probe; 448 449#ifdef CONFIG_TCP_MD5SIG 450/* TCP AF-Specific parts; only used by MD5 Signature support so far */ 451 const struct tcp_sock_af_ops *af_specific; 452 453/* TCP MD5 Signature Option information */ 454 struct tcp_md5sig_info *md5sig_info; 455#endif 456 457 /* When the cookie options are generated and exchanged, then this 458 * object holds a reference to them (cookie_values->kref). Also 459 * contains related tcp_cookie_transactions fields. 460 */ 461 struct tcp_cookie_values *cookie_values; 462}; 463 464static inline struct tcp_sock *tcp_sk(const struct sock *sk) 465{ 466 return (struct tcp_sock *)sk; 467} 468 469struct tcp_timewait_sock { 470 struct inet_timewait_sock tw_sk; 471 u32 tw_rcv_nxt; 472 u32 tw_snd_nxt; 473 u32 tw_rcv_wnd; 474 u32 tw_ts_recent; 475 long tw_ts_recent_stamp; 476#ifdef CONFIG_TCP_MD5SIG 477 u16 tw_md5_keylen; 478 u8 tw_md5_key[TCP_MD5SIG_MAXKEYLEN]; 479#endif 480 /* Few sockets in timewait have cookies; in that case, then this 481 * object holds a reference to them (tw_cookie_values->kref). 482 */ 483 struct tcp_cookie_values *tw_cookie_values; 484}; 485 486static inline struct tcp_timewait_sock *tcp_twsk(const struct sock *sk) 487{ 488 return (struct tcp_timewait_sock *)sk; 489} 490 491#endif /* __KERNEL__ */ 492 493#endif /* _LINUX_TCP_H */ 494