123187Smckusick /* 229147Smckusick * Copyright (c) 1982, 1986 Regents of the University of California. 332787Sbostic * All rights reserved. 423187Smckusick * 5*44483Sbostic * %sccs.include.redist.c% 632787Sbostic * 7*44483Sbostic * @(#)tcp.h 7.7 (Berkeley) 06/28/90 823187Smckusick */ 94573Swnj 105085Swnj typedef u_long tcp_seq; 114573Swnj /* 124899Swnj * TCP header. 134924Swnj * Per RFC 793, September, 1981. 144573Swnj */ 154899Swnj struct tcphdr { 164899Swnj u_short th_sport; /* source port */ 174899Swnj u_short th_dport; /* destination port */ 185085Swnj tcp_seq th_seq; /* sequence number */ 195085Swnj tcp_seq th_ack; /* acknowledgement number */ 2044373Skarels #if BYTE_ORDER == LITTLE_ENDIAN 219992Ssam u_char th_x2:4, /* (unused) */ 224899Swnj th_off:4; /* data offset */ 239992Ssam #endif 2444373Skarels #if BYTE_ORDER == BIG_ENDIAN 2529923Skarels u_char th_off:4, /* data offset */ 2629923Skarels th_x2:4; /* (unused) */ 2729923Skarels #endif 284575Swnj u_char th_flags; 295065Swnj #define TH_FIN 0x01 305065Swnj #define TH_SYN 0x02 315065Swnj #define TH_RST 0x04 325065Swnj #define TH_PUSH 0x08 335065Swnj #define TH_ACK 0x10 345065Swnj #define TH_URG 0x20 354899Swnj u_short th_win; /* window */ 364899Swnj u_short th_sum; /* checksum */ 374899Swnj u_short th_urp; /* urgent pointer */ 384499Swnj }; 395440Swnj 405440Swnj #define TCPOPT_EOL 0 415440Swnj #define TCPOPT_NOP 1 425440Swnj #define TCPOPT_MAXSEG 2 4317316Skarels 4417316Skarels /* 4526259Skarels * Default maximum segment size for TCP. 4626259Skarels * With an IP MSS of 576, this is 536, 4726259Skarels * but 512 is probably more convenient. 4844373Skarels * This should be defined as MIN(512, IP_MSS - sizeof (struct tcpiphdr)). 4917316Skarels */ 5044373Skarels #define TCP_MSS 512 5125895Skarels 5244373Skarels #define TCP_MAXWIN 65535 /* largest value for window */ 5344373Skarels 5425895Skarels /* 5525895Skarels * User-settable options (used with setsockopt). 5625895Skarels */ 5725895Skarels #define TCP_NODELAY 0x01 /* don't delay send to coalesce packets */ 5825895Skarels #define TCP_MAXSEG 0x02 /* set maximum segment size */ 59