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tcp.h revision 1.20 
      1 /*	$NetBSD: tcp.h,v 1.20 2005/07/21 17:32:11 riz Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1982, 1986, 1993
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  * 3. Neither the name of the University nor the names of its contributors
     16  *    may be used to endorse or promote products derived from this software
     17  *    without specific prior written permission.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     29  * SUCH DAMAGE.
     30  *
     31  *	@(#)tcp.h	8.1 (Berkeley) 6/10/93
     32  */
     33 
     34 #ifndef _NETINET_TCP_H_
     35 #define _NETINET_TCP_H_
     36 
     37 #include <sys/featuretest.h>
     38 
     39 #if defined(_NETBSD_SOURCE)
     40 
     41 typedef u_int32_t tcp_seq;
     42 /*
     43  * TCP header.
     44  * Per RFC 793, September, 1981.
     45  * Updated by RFC 3168, September, 2001.
     46  */
     47 struct tcphdr {
     48 	u_int16_t th_sport;		/* source port */
     49 	u_int16_t th_dport;		/* destination port */
     50 	tcp_seq	  th_seq;		/* sequence number */
     51 	tcp_seq	  th_ack;		/* acknowledgement number */
     52 #if BYTE_ORDER == LITTLE_ENDIAN
     53 	/*LINTED non-portable bitfields*/
     54 	u_int8_t  th_x2:4,		/* (unused) */
     55 		  th_off:4;		/* data offset */
     56 #endif
     57 #if BYTE_ORDER == BIG_ENDIAN
     58 	/*LINTED non-portable bitfields*/
     59 	u_int8_t  th_off:4,		/* data offset */
     60 		  th_x2:4;		/* (unused) */
     61 #endif
     62 	u_int8_t  th_flags;
     63 #define	TH_FIN	  0x01
     64 #define	TH_SYN	  0x02
     65 #define	TH_RST	  0x04
     66 #define	TH_PUSH	  0x08
     67 #define	TH_ACK	  0x10
     68 #define	TH_URG	  0x20
     69 #define	TH_ECE	  0x40			/* (unimplemented) */
     70 #define	TH_CWR	  0x80			/* (unimplemented) */
     71 	u_int16_t th_win;			/* window */
     72 	u_int16_t th_sum;			/* checksum */
     73 	u_int16_t th_urp;			/* urgent pointer */
     74 } __attribute__((__packed__));
     75 
     76 #define	TCPOPT_EOL		0
     77 #define	TCPOPT_NOP		1
     78 #define	TCPOPT_MAXSEG		2
     79 #define	   TCPOLEN_MAXSEG		4
     80 #define	TCPOPT_WINDOW		3
     81 #define	   TCPOLEN_WINDOW		3
     82 #define	TCPOPT_SACK_PERMITTED	4		/* Experimental */
     83 #define	   TCPOLEN_SACK_PERMITTED	2
     84 #define	TCPOPT_SACK		5		/* Experimental */
     85 #define	TCPOPT_TIMESTAMP	8
     86 #define	   TCPOLEN_TIMESTAMP		10
     87 #define	   TCPOLEN_TSTAMP_APPA		(TCPOLEN_TIMESTAMP+2) /* appendix A */
     88 
     89 #define TCPOPT_TSTAMP_HDR	\
     90     (TCPOPT_NOP<<24|TCPOPT_NOP<<16|TCPOPT_TIMESTAMP<<8|TCPOLEN_TIMESTAMP)
     91 
     92 #define	TCPOPT_SIGNATURE	19		/* Keyed MD5: RFC 2385 */
     93 #define	   TCPOLEN_SIGNATURE		18
     94 #define    TCPOLEN_SIGLEN		(TCPOLEN_SIGNATURE+2) /* padding */
     95 
     96 #define MAX_TCPOPTLEN	40	/* max # bytes that go in options */
     97 
     98 /*
     99  * Default maximum segment size for TCP.
    100  * With an IP MSS of 576, this is 536,
    101  * but 512 is probably more convenient.
    102  * This should be defined as min(512, IP_MSS - sizeof (struct tcpiphdr)).
    103  */
    104 #define	TCP_MSS		512
    105 
    106 #define	TCP_MAXWIN	65535	/* largest value for (unscaled) window */
    107 
    108 #define	TCP_MAX_WINSHIFT	14	/* maximum window shift */
    109 
    110 #define	TCP_MAXBURST	4	/* maximum segments in a burst */
    111 
    112 #endif /* _NETBSD_SOURCE */
    113 
    114 /*
    115  * User-settable options (used with setsockopt).
    116  */
    117 #define	TCP_NODELAY	0x01	/* don't delay send to coalesce packets */
    118 #define	TCP_MAXSEG	0x02	/* set maximum segment size */
    119 /* Bits 0x04, 0x08 reserved for FreeBSD compatibility: TCP_NOPUSH, TCP_NOOPT */
    120 #define TCP_MD5SIG	0x10	/* use MD5 digests (RFC2385) */
    121 #endif /* _NETINET_TCP_H_ */
    122