1 /* $OpenBSD: tcp.h,v 1.9 2001/06/09 07:03:43 angelos 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. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * @(#)tcp.h 8.1 (Berkeley) 6/10/93 37 */ 38 39 #ifndef _NETINET_TCP_H_ 40 #define _NETINET_TCP_H_ 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_int8_t th_x2:4, /* (unused) */ 55 th_off:4; /* data offset */ 56 #endif 57 #if BYTE_ORDER == BIG_ENDIAN 58 u_int8_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 u_int16_t th_win; /* window */ 69 u_int16_t th_sum; /* checksum */ 70 u_int16_t th_urp; /* urgent pointer */ 71 }; 72 #define th_reseqlen th_urp /* TCP data length for 73 resequencing/reassembly */ 74 75 #define TCPOPT_EOL 0 76 #define TCPOPT_NOP 1 77 #define TCPOPT_MAXSEG 2 78 #define TCPOLEN_MAXSEG 4 79 #define TCPOPT_WINDOW 3 80 #define TCPOLEN_WINDOW 3 81 #define TCPOPT_SACK_PERMITTED 4 /* Experimental */ 82 #define TCPOLEN_SACK_PERMITTED 2 83 #define TCPOPT_SACK 5 /* Experimental */ 84 #define TCPOLEN_SACK 8 /* 2*sizeof(tcp_seq) */ 85 #define TCPOPT_TIMESTAMP 8 86 #define TCPOLEN_TIMESTAMP 10 87 #define TCPOLEN_TSTAMP_APPA (TCPOLEN_TIMESTAMP+2) /* appendix A */ 88 #define TCPOPT_SIGNATURE 19 89 #define TCPOLEN_SIGNATURE 18 90 91 #define MAX_TCPOPTLEN 40 /* Absolute maximum TCP options len */ 92 93 #define TCPOPT_TSTAMP_HDR \ 94 (TCPOPT_NOP<<24|TCPOPT_NOP<<16|TCPOPT_TIMESTAMP<<8|TCPOLEN_TIMESTAMP) 95 96 /* Option definitions */ 97 #define TCPOPT_SACK_PERMIT_HDR \ 98 (TCPOPT_NOP<<24|TCPOPT_NOP<<16|TCPOPT_SACK_PERMITTED<<8|TCPOLEN_SACK_PERMITTED) 99 #define TCPOPT_SACK_HDR (TCPOPT_NOP<<24|TCPOPT_NOP<<16|TCPOPT_SACK<<8) 100 /* Miscellaneous constants */ 101 #define MAX_SACK_BLKS 6 /* Max # SACK blocks stored at sender side */ 102 #define TCP_MAX_SACK 3 /* MAX # SACKs sent in any segment */ 103 104 #define TCP_MAXBURST 4 /* Max # packets after leaving Fast Rxmit */ 105 106 /* 107 * Default maximum segment size for TCP. 108 * With an IP MSS of 576, this is 536, 109 * but 512 is probably more convenient. 110 * This should be defined as min(512, IP_MSS - sizeof (struct tcpiphdr)). 111 */ 112 #define TCP_MSS 512 113 114 #define TCP_MAXWIN 65535 /* largest value for (unscaled) window */ 115 116 #define TCP_MAX_WINSHIFT 14 /* maximum window shift */ 117 118 /* 119 * User-settable options (used with setsockopt). 120 */ 121 #define TCP_NODELAY 0x01 /* don't delay send to coalesce pkts */ 122 #define TCP_MAXSEG 0x02 /* set maximum segment size */ 123 #define TCP_SIGNATURE_ENABLE 0x04 /* enable TCP MD5 signature option */ 124 #define TCP_SACK_DISABLE 0x300 /* disable SACKs (if enabled by def.) */ 125 126 #endif /* _NETINET_TCP_H_ */ 127