1 /* $OpenBSD: tcp.h,v 1.18 2010/10/23 22:50:07 guenther 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 #include <sys/cdefs.h> 39 40 #if __BSD_VISIBLE 41 42 typedef u_int32_t tcp_seq; 43 44 /* 45 * TCP header. 46 * Per RFC 793, September, 1981. 47 */ 48 struct tcphdr { 49 u_int16_t th_sport; /* source port */ 50 u_int16_t th_dport; /* destination port */ 51 tcp_seq th_seq; /* sequence number */ 52 tcp_seq th_ack; /* acknowledgement number */ 53 #if _BYTE_ORDER == _LITTLE_ENDIAN 54 u_int32_t th_x2:4, /* (unused) */ 55 th_off:4; /* data offset */ 56 #endif 57 #if _BYTE_ORDER == _BIG_ENDIAN 58 u_int32_t th_off:4, /* data offset */ 59 th_x2:4; /* (unused) */ 60 #endif 61 u_int8_t th_flags; 62 #define TH_FIN 0x01 63 #define TH_SYN 0x02 64 #define TH_RST 0x04 65 #define TH_PUSH 0x08 66 #define TH_ACK 0x10 67 #define TH_URG 0x20 68 #define TH_ECE 0x40 69 #define TH_CWR 0x80 70 u_int16_t th_win; /* window */ 71 u_int16_t th_sum; /* checksum */ 72 u_int16_t th_urp; /* urgent pointer */ 73 }; 74 #define th_reseqlen th_urp /* TCP data length for 75 resequencing/reassembly */ 76 77 #define TCPOPT_EOL 0 78 #define TCPOPT_NOP 1 79 #define TCPOPT_MAXSEG 2 80 #define TCPOLEN_MAXSEG 4 81 #define TCPOPT_WINDOW 3 82 #define TCPOLEN_WINDOW 3 83 #define TCPOPT_SACK_PERMITTED 4 /* Experimental */ 84 #define TCPOLEN_SACK_PERMITTED 2 85 #define TCPOPT_SACK 5 /* Experimental */ 86 #define TCPOLEN_SACK 8 /* 2*sizeof(tcp_seq) */ 87 #define TCPOPT_TIMESTAMP 8 88 #define TCPOLEN_TIMESTAMP 10 89 #define TCPOLEN_TSTAMP_APPA (TCPOLEN_TIMESTAMP+2) /* appendix A */ 90 #define TCPOPT_SIGNATURE 19 91 #define TCPOLEN_SIGNATURE 18 92 #define TCPOLEN_SIGLEN (TCPOLEN_SIGNATURE+2) /* padding */ 93 94 #define MAX_TCPOPTLEN 40 /* Absolute maximum TCP options len */ 95 96 #define TCPOPT_TSTAMP_HDR \ 97 (TCPOPT_NOP<<24|TCPOPT_NOP<<16|TCPOPT_TIMESTAMP<<8|TCPOLEN_TIMESTAMP) 98 99 /* Option definitions */ 100 #define TCPOPT_SACK_PERMIT_HDR \ 101 (TCPOPT_NOP<<24|TCPOPT_NOP<<16|TCPOPT_SACK_PERMITTED<<8|TCPOLEN_SACK_PERMITTED) 102 #define TCPOPT_SACK_HDR (TCPOPT_NOP<<24|TCPOPT_NOP<<16|TCPOPT_SACK<<8) 103 /* Miscellaneous constants */ 104 #define MAX_SACK_BLKS 6 /* Max # SACK blocks stored at sender side */ 105 #define TCP_MAX_SACK 3 /* MAX # SACKs sent in any segment */ 106 107 #define TCP_MAXBURST 4 /* Max # packets after leaving Fast Rxmit */ 108 109 /* 110 * Default maximum segment size for TCP. 111 * With an IP MSS of 576, this is 536, 112 * but 512 is probably more convenient. 113 * This should be defined as min(512, IP_MSS - sizeof (struct tcpiphdr)). 114 */ 115 #define TCP_MSS 512 116 117 #define TCP_MAXWIN 65535 /* largest value for (unscaled) window */ 118 119 #define TCP_MAX_WINSHIFT 14 /* maximum window shift */ 120 121 #endif /* __BSD_VISIBLE */ 122 123 /* 124 * User-settable options (used with setsockopt). 125 */ 126 #define TCP_NODELAY 0x01 /* don't delay send to coalesce pkts */ 127 #define TCP_MAXSEG 0x02 /* set maximum segment size */ 128 #define TCP_MD5SIG 0x04 /* enable TCP MD5 signature option */ 129 #define TCP_SACK_ENABLE 0x08 /* enable SACKs (if disabled by def.) */ 130 131 #endif /* _NETINET_TCP_H_ */ 132