/*
 * Copyright (c) 1982, 1986 Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms are permitted
 * provided that the above copyright notice and this paragraph are
 * duplicated in all such forms and that any documentation,
 * advertising materials, and other materials related to such
 * distribution and use acknowledge that the software was developed
 * by the University of California, Berkeley.  The name of the
 * University may not be used to endorse or promote products derived
 * from this software without specific prior written permission.
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 *
 *	@(#)tcp.h	7.4.1.2 (Berkeley) 2/17/89
 * $Header: /smsa/bsd:include/netinet/tcp.h:bsd  1.8  $
 * $Source: /smsa/bsd:include/netinet/tcp.h: $
 *
 * Copyright (c) 1988 Acorn Computers Ltd., Cambridge, England
 */
/* @(#)tcp.h	1.1 87/07/01 3.2/4.3NFSSRC */
/*
 * Copyright (c) 1982, 1986 Regents of the University of California.
 * All rights reserved.  The Berkeley software License Agreement
 * specifies the terms and conditions for redistribution.
 *
 *	@(#)tcp.h	7.1 (Berkeley) 6/5/86
 */

#ifndef __netinet_tcp_h
#define __netinet_tcp_h

#ifndef BYTE_ORDER
/*
 * Definitions for byte order,
 * according to byte significance from low address to high.
 */
#define	LITTLE_ENDIAN	1234	/* least-significant byte first (vax) */
#define	BIG_ENDIAN	4321	/* most-significant byte first (IBM, net) */
#define	PDP_ENDIAN	3412	/* LSB first in word, MSW first in long (pdp) */

#define	BYTE_ORDER	LITTLE_ENDIAN
#endif BYTE_ORDER

typedef	u_long	tcp_seq;
/*
 * 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 */

	u_char	th_x2:4,		/* (unused) */
		th_off:4;		/* data offset */
	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
	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

/*
 * Default maximum segment size for TCP.
 * With an IP MSS of 576, this is 536,
 * but 512 is probably more convenient.
 */
#ifdef	lint
#define	TCP_MSS	536
#else
#ifndef IP_MSS
#define	IP_MSS	576
#endif
#define	TCP_MSS	MIN(512, IP_MSS - sizeof (struct tcpiphdr))
#endif

/*
 * User-settable options (used with setsockopt).
 */
#define	TCP_NODELAY	0x01	/* don't delay send to coalesce packets */
#define	TCP_MAXSEG	0x02	/* set maximum segment size */

#endif/*__netinet_tcp_h*/

/* EOF tcp.h */
