1 /* $OpenBSD: tcp.h,v 1.17 2006/04/27 02:19:32 tedu Exp $ */ 2 /* $NetBSD: tcp.h,v 1.8 1995/04/17 05:32:58 cgd Exp $ */ 3 4 /* 5 * Copyright (c) 1982, 1986, 1993 6 * The Regents of the University of California. All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 * 32 * @(#)tcp.h 8.1 (Berkeley) 6/10/93 33 */ 34 35 #ifndef _NETINET_TCP_H_ 36 #define _NETINET_TCP_H_ 37 38 typedef u_int32_t tcp_seq; 39 40 /* 41 * TCP header. 42 * Per RFC 793, September, 1981. 43 */ 44 struct tcphdr { 45 u_int16_t th_sport; /* source port */ 46 u_int16_t th_dport; /* destination port */ 47 tcp_seq th_seq; /* sequence number */ 48 tcp_seq th_ack; /* acknowledgement number */ 49 #if _BYTE_ORDER == _LITTLE_ENDIAN 50 u_int th_x2:4, /* (unused) */ 51 th_off:4; /* data offset */ 52 #endif 53 #if _BYTE_ORDER == _BIG_ENDIAN 54 u_int th_off:4, /* data offset */ 55 th_x2:4; /* (unused) */ 56 #endif 57 u_int8_t th_flags; 58 #define TH_FIN 0x01 59 #define TH_SYN 0x02 60 #define TH_RST 0x04 61 #define TH_PUSH 0x08 62 #define TH_ACK 0x10 63 #define TH_URG 0x20 64 #define TH_ECE 0x40 65 #define TH_CWR 0x80 66 u_int16_t th_win; /* window */ 67 u_int16_t th_sum; /* checksum */ 68 u_int16_t th_urp; /* urgent pointer */ 69 }; 70 #define th_reseqlen th_urp /* TCP data length for 71 resequencing/reassembly */ 72 73 #define TCPOPT_EOL 0 74 #define TCPOPT_NOP 1 75 #define TCPOPT_MAXSEG 2 76 #define TCPOLEN_MAXSEG 4 77 #define TCPOPT_WINDOW 3 78 #define TCPOLEN_WINDOW 3 79 #define TCPOPT_SACK_PERMITTED 4 /* Experimental */ 80 #define TCPOLEN_SACK_PERMITTED 2 81 #define TCPOPT_SACK 5 /* Experimental */ 82 #define TCPOLEN_SACK 8 /* 2*sizeof(tcp_seq) */ 83 #define TCPOPT_TIMESTAMP 8 84 #define TCPOLEN_TIMESTAMP 10 85 #define TCPOLEN_TSTAMP_APPA (TCPOLEN_TIMESTAMP+2) /* appendix A */ 86 #define TCPOPT_SIGNATURE 19 87 #define TCPOLEN_SIGNATURE 18 88 #define TCPOLEN_SIGLEN (TCPOLEN_SIGNATURE+2) /* padding */ 89 90 #define MAX_TCPOPTLEN 40 /* Absolute maximum TCP options len */ 91 92 #define TCPOPT_TSTAMP_HDR \ 93 (TCPOPT_NOP<<24|TCPOPT_NOP<<16|TCPOPT_TIMESTAMP<<8|TCPOLEN_TIMESTAMP) 94 95 /* Option definitions */ 96 #define TCPOPT_SACK_PERMIT_HDR \ 97 (TCPOPT_NOP<<24|TCPOPT_NOP<<16|TCPOPT_SACK_PERMITTED<<8|TCPOLEN_SACK_PERMITTED) 98 #define TCPOPT_SACK_HDR (TCPOPT_NOP<<24|TCPOPT_NOP<<16|TCPOPT_SACK<<8) 99 /* Miscellaneous constants */ 100 #define MAX_SACK_BLKS 6 /* Max # SACK blocks stored at sender side */ 101 #define TCP_MAX_SACK 3 /* MAX # SACKs sent in any segment */ 102 103 #define TCP_MAXBURST 4 /* Max # packets after leaving Fast Rxmit */ 104 105 /* 106 * Default maximum segment size for TCP. 107 * With an IP MSS of 576, this is 536, 108 * but 512 is probably more convenient. 109 * This should be defined as min(512, IP_MSS - sizeof (struct tcpiphdr)). 110 */ 111 #define TCP_MSS 512 112 113 #define TCP_MAXWIN 65535 /* largest value for (unscaled) window */ 114 115 #define TCP_MAX_WINSHIFT 14 /* maximum window shift */ 116 117 /* 118 * User-settable options (used with setsockopt). 119 */ 120 #define TCP_NODELAY 0x01 /* don't delay send to coalesce pkts */ 121 #define TCP_MAXSEG 0x02 /* set maximum segment size */ 122 #define TCP_MD5SIG 0x04 /* enable TCP MD5 signature option */ 123 #define TCP_SACK_ENABLE 0x08 /* enable SACKs (if disabled by def.) */ 124 125 #endif /* _NETINET_TCP_H_ */ 126