tcp.h revision 124437
1/* 2 * Copyright (c) 1982, 1986, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * @(#)tcp.h 8.1 (Berkeley) 6/10/93 34 * $FreeBSD: head/sys/netinet/tcp.h 124437 2004-01-12 15:46:04Z andre $ 35 */ 36 37#ifndef _NETINET_TCP_H_ 38#define _NETINET_TCP_H_ 39 40#include <sys/cdefs.h> 41 42#if __BSD_VISIBLE 43 44typedef u_int32_t tcp_seq; 45typedef u_int32_t tcp_cc; /* connection count per rfc1644 */ 46 47#define tcp6_seq tcp_seq /* for KAME src sync over BSD*'s */ 48#define tcp6hdr tcphdr /* for KAME src sync over BSD*'s */ 49 50/* 51 * TCP header. 52 * Per RFC 793, September, 1981. 53 */ 54struct tcphdr { 55 u_short th_sport; /* source port */ 56 u_short th_dport; /* destination port */ 57 tcp_seq th_seq; /* sequence number */ 58 tcp_seq th_ack; /* acknowledgement number */ 59#if BYTE_ORDER == LITTLE_ENDIAN 60 u_int th_x2:4, /* (unused) */ 61 th_off:4; /* data offset */ 62#endif 63#if BYTE_ORDER == BIG_ENDIAN 64 u_int th_off:4, /* data offset */ 65 th_x2:4; /* (unused) */ 66#endif 67 u_char th_flags; 68#define TH_FIN 0x01 69#define TH_SYN 0x02 70#define TH_RST 0x04 71#define TH_PUSH 0x08 72#define TH_ACK 0x10 73#define TH_URG 0x20 74#define TH_ECE 0x40 75#define TH_CWR 0x80 76#define TH_FLAGS (TH_FIN|TH_SYN|TH_RST|TH_ACK|TH_URG|TH_ECE|TH_CWR) 77 78 u_short th_win; /* window */ 79 u_short th_sum; /* checksum */ 80 u_short th_urp; /* urgent pointer */ 81}; 82 83#define TCPOPT_EOL 0 84#define TCPOPT_NOP 1 85#define TCPOPT_MAXSEG 2 86#define TCPOLEN_MAXSEG 4 87#define TCPOPT_WINDOW 3 88#define TCPOLEN_WINDOW 3 89#define TCPOPT_SACK_PERMITTED 4 /* Experimental */ 90#define TCPOLEN_SACK_PERMITTED 2 91#define TCPOPT_SACK 5 /* Experimental */ 92#define TCPOPT_TIMESTAMP 8 93#define TCPOLEN_TIMESTAMP 10 94#define TCPOLEN_TSTAMP_APPA (TCPOLEN_TIMESTAMP+2) /* appendix A */ 95#define TCPOPT_TSTAMP_HDR \ 96 (TCPOPT_NOP<<24|TCPOPT_NOP<<16|TCPOPT_TIMESTAMP<<8|TCPOLEN_TIMESTAMP) 97 98#define TCPOPT_CC 11 /* CC options: RFC-1644 */ 99#define TCPOPT_CCNEW 12 100#define TCPOPT_CCECHO 13 101#define TCPOLEN_CC 6 102#define TCPOLEN_CC_APPA (TCPOLEN_CC+2) 103#define TCPOPT_CC_HDR(ccopt) \ 104 (TCPOPT_NOP<<24|TCPOPT_NOP<<16|(ccopt)<<8|TCPOLEN_CC) 105 106/* 107 * Default maximum segment size for TCP. 108 * With an IP MTU 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 * TCP_MINMSS is defined to be 216 which is fine for the smallest 115 * link MTU (256 bytes, AX.25 packet radio) in the Internet. 116 * However it is very unlikely to come across such low MTU interfaces 117 * these days (anno dato 2003). 118 * See tcp_subr.c tcp_minmss SYSCTL declaration for more comments. 119 * Setting this to "0" disables the minmss check. 120 */ 121#define TCP_MINMSS 216 122/* 123 * TCP_MINMSSOVERLOAD is defined to be 1000 which should cover any type 124 * of interactive TCP session. 125 * See tcp_subr.c tcp_minmssoverload SYSCTL declaration and tcp_input.c 126 * for more comments. 127 * Setting this to "0" disables the minmssoverload check. 128 */ 129#define TCP_MINMSSOVERLOAD 0 /* XXX: Disabled until refined */ 130 131/* 132 * Default maximum segment size for TCP6. 133 * With an IP6 MSS of 1280, this is 1220, 134 * but 1024 is probably more convenient. (xxx kazu in doubt) 135 * This should be defined as MIN(1024, IP6_MSS - sizeof (struct tcpip6hdr)) 136 */ 137#define TCP6_MSS 1024 138 139#define TCP_MAXWIN 65535 /* largest value for (unscaled) window */ 140#define TTCP_CLIENT_SND_WND 4096 /* dflt send window for T/TCP client */ 141 142#define TCP_MAX_WINSHIFT 14 /* maximum window shift */ 143 144#define TCP_MAXBURST 4 /* maximum segments in a burst */ 145 146#define TCP_MAXHLEN (0xf<<2) /* max length of header in bytes */ 147#define TCP_MAXOLEN (TCP_MAXHLEN - sizeof(struct tcphdr)) 148 /* max space left for options */ 149#endif /* __BSD_VISIBLE */ 150 151/* 152 * User-settable options (used with setsockopt). 153 */ 154#define TCP_NODELAY 0x01 /* don't delay send to coalesce packets */ 155#if __BSD_VISIBLE 156#define TCP_MAXSEG 0x02 /* set maximum segment size */ 157#define TCP_NOPUSH 0x04 /* don't push last block of write */ 158#define TCP_NOOPT 0x08 /* don't use TCP options */ 159#endif 160 161#endif /* !_NETINET_TCP_H_ */ 162