d06f3bef4e
A complete rationale and discussion is given in this message and the resulting discussion: http://docs.freebsd.org/cgi/mid.cgi?4177C8AD.6060706 Note that this commit removes only the functional part of T/TCP from the tcp_* related functions in the kernel. Other features introduced with RFC1644 are left intact (socket layer changes, sendmsg(2) on connection oriented protocols) and are meant to be reused by a simpler and less intrusive reimplemention of the previous T/TCP functionality. Discussed on: -arch
165 lines
5.7 KiB
C
165 lines
5.7 KiB
C
/*
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* Copyright (c) 1982, 1986, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)tcp.h 8.1 (Berkeley) 6/10/93
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* $FreeBSD$
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*/
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#ifndef _NETINET_TCP_H_
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#define _NETINET_TCP_H_
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#include <sys/cdefs.h>
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#if __BSD_VISIBLE
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typedef u_int32_t tcp_seq;
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#define tcp6_seq tcp_seq /* for KAME src sync over BSD*'s */
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#define tcp6hdr tcphdr /* for KAME src sync over BSD*'s */
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/*
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* TCP header.
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* Per RFC 793, September, 1981.
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*/
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struct tcphdr {
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u_short th_sport; /* source port */
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u_short th_dport; /* destination port */
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tcp_seq th_seq; /* sequence number */
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tcp_seq th_ack; /* acknowledgement number */
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#if BYTE_ORDER == LITTLE_ENDIAN
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u_int th_x2:4, /* (unused) */
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th_off:4; /* data offset */
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#endif
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#if BYTE_ORDER == BIG_ENDIAN
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u_int th_off:4, /* data offset */
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th_x2:4; /* (unused) */
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#endif
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u_char th_flags;
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#define TH_FIN 0x01
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#define TH_SYN 0x02
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#define TH_RST 0x04
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#define TH_PUSH 0x08
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#define TH_ACK 0x10
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#define TH_URG 0x20
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#define TH_ECE 0x40
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#define TH_CWR 0x80
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#define TH_FLAGS (TH_FIN|TH_SYN|TH_RST|TH_ACK|TH_URG|TH_ECE|TH_CWR)
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u_short th_win; /* window */
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u_short th_sum; /* checksum */
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u_short th_urp; /* urgent pointer */
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};
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#define TCPOPT_EOL 0
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#define TCPOPT_NOP 1
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#define TCPOPT_MAXSEG 2
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#define TCPOLEN_MAXSEG 4
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#define TCPOPT_WINDOW 3
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#define TCPOLEN_WINDOW 3
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#define TCPOPT_SACK_PERMITTED 4 /* Experimental */
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#define TCPOLEN_SACK_PERMITTED 2
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#define TCPOPT_SACK 5 /* Experimental */
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#define TCPOLEN_SACK 8 /* 2*sizeof(tcp_seq) */
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#define TCPOPT_TIMESTAMP 8
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#define TCPOLEN_TIMESTAMP 10
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#define TCPOLEN_TSTAMP_APPA (TCPOLEN_TIMESTAMP+2) /* appendix A */
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#define TCPOPT_TSTAMP_HDR \
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(TCPOPT_NOP<<24|TCPOPT_NOP<<16|TCPOPT_TIMESTAMP<<8|TCPOLEN_TIMESTAMP)
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#define MAX_TCPOPTLEN 40 /* Absolute maximum TCP options len */
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#define TCPOPT_SIGNATURE 19 /* Keyed MD5: RFC 2385 */
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#define TCPOLEN_SIGNATURE 18
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/* Option definitions */
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#define TCPOPT_SACK_PERMIT_HDR \
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(TCPOPT_NOP<<24|TCPOPT_NOP<<16|TCPOPT_SACK_PERMITTED<<8|TCPOLEN_SACK_PERMITTED)
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#define TCPOPT_SACK_HDR (TCPOPT_NOP<<24|TCPOPT_NOP<<16|TCPOPT_SACK<<8)
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/* Miscellaneous constants */
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#define MAX_SACK_BLKS 6 /* Max # SACK blocks stored at sender side */
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#define TCP_MAX_SACK 3 /* MAX # SACKs sent in any segment */
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/*
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* Default maximum segment size for TCP.
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* With an IP MTU of 576, this is 536,
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* but 512 is probably more convenient.
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* This should be defined as MIN(512, IP_MSS - sizeof (struct tcpiphdr)).
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*/
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#define TCP_MSS 512
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/*
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* TCP_MINMSS is defined to be 216 which is fine for the smallest
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* link MTU (256 bytes, AX.25 packet radio) in the Internet.
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* However it is very unlikely to come across such low MTU interfaces
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* these days (anno dato 2003).
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* See tcp_subr.c tcp_minmss SYSCTL declaration for more comments.
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* Setting this to "0" disables the minmss check.
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*/
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#define TCP_MINMSS 216
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/*
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* TCP_MINMSSOVERLOAD is defined to be 1000 which should cover any type
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* of interactive TCP session.
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* See tcp_subr.c tcp_minmssoverload SYSCTL declaration and tcp_input.c
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* for more comments.
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* Setting this to "0" disables the minmssoverload check.
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*/
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#define TCP_MINMSSOVERLOAD 0 /* XXX: Disabled until refined */
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/*
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* Default maximum segment size for TCP6.
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* With an IP6 MSS of 1280, this is 1220,
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* but 1024 is probably more convenient. (xxx kazu in doubt)
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* This should be defined as MIN(1024, IP6_MSS - sizeof (struct tcpip6hdr))
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*/
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#define TCP6_MSS 1024
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#define TCP_MAXWIN 65535 /* largest value for (unscaled) window */
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#define TTCP_CLIENT_SND_WND 4096 /* dflt send window for T/TCP client */
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#define TCP_MAX_WINSHIFT 14 /* maximum window shift */
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#define TCP_MAXBURST 4 /* maximum segments in a burst */
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#define TCP_MAXHLEN (0xf<<2) /* max length of header in bytes */
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#define TCP_MAXOLEN (TCP_MAXHLEN - sizeof(struct tcphdr))
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/* max space left for options */
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#endif /* __BSD_VISIBLE */
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/*
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* User-settable options (used with setsockopt).
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*/
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#define TCP_NODELAY 0x01 /* don't delay send to coalesce packets */
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#if __BSD_VISIBLE
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#define TCP_MAXSEG 0x02 /* set maximum segment size */
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#define TCP_NOPUSH 0x04 /* don't push last block of write */
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#define TCP_NOOPT 0x08 /* don't use TCP options */
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#define TCP_MD5SIG 0x10 /* use MD5 digests (RFC2385) */
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#endif
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#endif /* !_NETINET_TCP_H_ */
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