FreeBSD-5.3/sys/netinet/tcp.h
/*
* Copyright (c) 1982, 1986, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)tcp.h 8.1 (Berkeley) 6/10/93
* $FreeBSD: src/sys/netinet/tcp.h,v 1.26 2004/08/16 18:32:07 rwatson Exp $
*/
#ifndef _NETINET_TCP_H_
#define _NETINET_TCP_H_
#include <sys/cdefs.h>
#if __BSD_VISIBLE
typedef u_int32_t tcp_seq;
typedef u_int32_t tcp_cc; /* connection count per rfc1644 */
#define tcp6_seq tcp_seq /* for KAME src sync over BSD*'s */
#define tcp6hdr tcphdr /* for KAME src sync over BSD*'s */
/*
* TCP header.
* Per RFC 793, September, 1981.
*/
struct tcphdr {
u_short th_sport; /* source port */
u_short th_dport; /* destination port */
tcp_seq th_seq; /* sequence number */
tcp_seq th_ack; /* acknowledgement number */
#if BYTE_ORDER == LITTLE_ENDIAN
u_int th_x2:4, /* (unused) */
th_off:4; /* data offset */
#endif
#if BYTE_ORDER == BIG_ENDIAN
u_int th_off:4, /* data offset */
th_x2:4; /* (unused) */
#endif
u_char th_flags;
#define TH_FIN 0x01
#define TH_SYN 0x02
#define TH_RST 0x04
#define TH_PUSH 0x08
#define TH_ACK 0x10
#define TH_URG 0x20
#define TH_ECE 0x40
#define TH_CWR 0x80
#define TH_FLAGS (TH_FIN|TH_SYN|TH_RST|TH_ACK|TH_URG|TH_ECE|TH_CWR)
u_short th_win; /* window */
u_short th_sum; /* checksum */
u_short th_urp; /* urgent pointer */
};
#define TCPOPT_EOL 0
#define TCPOPT_NOP 1
#define TCPOPT_MAXSEG 2
#define TCPOLEN_MAXSEG 4
#define TCPOPT_WINDOW 3
#define TCPOLEN_WINDOW 3
#define TCPOPT_SACK_PERMITTED 4 /* Experimental */
#define TCPOLEN_SACK_PERMITTED 2
#define TCPOPT_SACK 5 /* Experimental */
#define TCPOLEN_SACK 8 /* 2*sizeof(tcp_seq) */
#define TCPOPT_TIMESTAMP 8
#define TCPOLEN_TIMESTAMP 10
#define TCPOLEN_TSTAMP_APPA (TCPOLEN_TIMESTAMP+2) /* appendix A */
#define TCPOPT_TSTAMP_HDR \
(TCPOPT_NOP<<24|TCPOPT_NOP<<16|TCPOPT_TIMESTAMP<<8|TCPOLEN_TIMESTAMP)
#define MAX_TCPOPTLEN 40 /* Absolute maximum TCP options len */
#define TCPOPT_CC 11 /* CC options: RFC-1644 */
#define TCPOPT_CCNEW 12
#define TCPOPT_CCECHO 13
#define TCPOLEN_CC 6
#define TCPOLEN_CC_APPA (TCPOLEN_CC+2)
#define TCPOPT_CC_HDR(ccopt) \
(TCPOPT_NOP<<24|TCPOPT_NOP<<16|(ccopt)<<8|TCPOLEN_CC)
#define TCPOPT_SIGNATURE 19 /* Keyed MD5: RFC 2385 */
#define TCPOLEN_SIGNATURE 18
/* Option definitions */
#define TCPOPT_SACK_PERMIT_HDR \
(TCPOPT_NOP<<24|TCPOPT_NOP<<16|TCPOPT_SACK_PERMITTED<<8|TCPOLEN_SACK_PERMITTED)
#define TCPOPT_SACK_HDR (TCPOPT_NOP<<24|TCPOPT_NOP<<16|TCPOPT_SACK<<8)
/* Miscellaneous constants */
#define MAX_SACK_BLKS 6 /* Max # SACK blocks stored at sender side */
#define TCP_MAX_SACK 3 /* MAX # SACKs sent in any segment */
/*
* Default maximum segment size for TCP.
* With an IP MTU of 576, this is 536,
* but 512 is probably more convenient.
* This should be defined as MIN(512, IP_MSS - sizeof (struct tcpiphdr)).
*/
#define TCP_MSS 512
/*
* TCP_MINMSS is defined to be 216 which is fine for the smallest
* link MTU (256 bytes, AX.25 packet radio) in the Internet.
* However it is very unlikely to come across such low MTU interfaces
* these days (anno dato 2003).
* See tcp_subr.c tcp_minmss SYSCTL declaration for more comments.
* Setting this to "0" disables the minmss check.
*/
#define TCP_MINMSS 216
/*
* TCP_MINMSSOVERLOAD is defined to be 1000 which should cover any type
* of interactive TCP session.
* See tcp_subr.c tcp_minmssoverload SYSCTL declaration and tcp_input.c
* for more comments.
* Setting this to "0" disables the minmssoverload check.
*/
#define TCP_MINMSSOVERLOAD 0 /* XXX: Disabled until refined */
/*
* Default maximum segment size for TCP6.
* With an IP6 MSS of 1280, this is 1220,
* but 1024 is probably more convenient. (xxx kazu in doubt)
* This should be defined as MIN(1024, IP6_MSS - sizeof (struct tcpip6hdr))
*/
#define TCP6_MSS 1024
#define TCP_MAXWIN 65535 /* largest value for (unscaled) window */
#define TTCP_CLIENT_SND_WND 4096 /* dflt send window for T/TCP client */
#define TCP_MAX_WINSHIFT 14 /* maximum window shift */
#define TCP_MAXBURST 4 /* maximum segments in a burst */
#define TCP_MAXHLEN (0xf<<2) /* max length of header in bytes */
#define TCP_MAXOLEN (TCP_MAXHLEN - sizeof(struct tcphdr))
/* max space left for options */
#endif /* __BSD_VISIBLE */
/*
* User-settable options (used with setsockopt).
*/
#define TCP_NODELAY 0x01 /* don't delay send to coalesce packets */
#if __BSD_VISIBLE
#define TCP_MAXSEG 0x02 /* set maximum segment size */
#define TCP_NOPUSH 0x04 /* don't push last block of write */
#define TCP_NOOPT 0x08 /* don't use TCP options */
#define TCP_MD5SIG 0x10 /* use MD5 digests (RFC2385) */
#endif
#endif /* !_NETINET_TCP_H_ */