/*

 * 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.

 * 3. All advertising materials mentioning features or use of this software

 *    must display the following acknowledgement:

 *	This product includes software developed by the University of

 *	California, Berkeley and its contributors.

 * 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

 * tcp.h,v 1.3 1994/08/21 05:27:34 paul Exp

 */

#ifndef _TCP_H_

#define _TCP_H_

typedef	u_int32_t	tcp_seq;

#define      PR_SLOWHZ       2               /* 2 slow timeouts per second (approx) */

#define      PR_FASTHZ       5               /* 5 fast timeouts per second (not important) */

extern struct socket *tcp_last_so;

#define TCP_SNDSPACE 8192

#define TCP_RCVSPACE 8192

/*

 * TCP header.

 * Per RFC 793, September, 1981.

 */

struct tcphdr {

	u_int16_t	th_sport;		/* source port */

	u_int16_t	th_dport;		/* destination port */

	tcp_seq	th_seq;			/* sequence number */

	tcp_seq	th_ack;			/* acknowledgement number */

#ifdef WORDS_BIGENDIAN

	u_int	th_off:4,		/* data offset */

		th_x2:4;		/* (unused) */

#else

	u_int	th_x2:4,		/* (unused) */

		th_off:4;		/* data offset */

#endif

	u_int8_t	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_int16_t	th_win;			/* window */

	u_int16_t	th_sum;			/* checksum */

	u_int16_t	th_urp;			/* urgent pointer */

};

#include "tcp_var.h"

#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 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)

/*

 * Default maximum segment size for TCP.

 * With an IP MSS of 576, this is 536,

 * but 512 is probably more convenient.

 * This should be defined as MIN(512, IP_MSS - sizeof (struct tcpiphdr)).

 *

 * We make this 1460 because we only care about Ethernet in the qemu context.

 */

#define	TCP_MSS	1460

#define	TCP_MAXWIN	65535	/* largest value for (unscaled) window */

#define TCP_MAX_WINSHIFT	14	/* maximum window shift */

/*

 * User-settable options (used with setsockopt).

 *

 * We don't use the system headers on unix because we have conflicting

 * local structures. We can't avoid the system definitions on Windows,

 * so we undefine them.

 */

#undef TCP_NODELAY

#define	TCP_NODELAY	0x01	/* don't delay send to coalesce packets */

#undef TCP_MAXSEG

/* #define	TCP_MAXSEG	0x02 */	/* set maximum segment size */

/*

 * TCP FSM state definitions.

 * Per RFC793, September, 1981.

 */

#define TCP_NSTATES     11

#define TCPS_CLOSED             0       /* closed */

#define TCPS_LISTEN             1       /* listening for connection */

#define TCPS_SYN_SENT           2       /* active, have sent syn */

#define TCPS_SYN_RECEIVED       3       /* have send and received syn */

/* states < TCPS_ESTABLISHED are those where connections not established */

#define TCPS_ESTABLISHED        4       /* established */

#define TCPS_CLOSE_WAIT         5       /* rcvd fin, waiting for close */

/* states > TCPS_CLOSE_WAIT are those where user has closed */

#define TCPS_FIN_WAIT_1         6       /* have closed, sent fin */

#define TCPS_CLOSING            7       /* closed xchd FIN; await FIN ACK */

#define TCPS_LAST_ACK           8       /* had fin and close; await FIN ACK */

/* states > TCPS_CLOSE_WAIT && < TCPS_FIN_WAIT_2 await ACK of FIN */

#define TCPS_FIN_WAIT_2         9       /* have closed, fin is acked */

#define TCPS_TIME_WAIT          10      /* in 2*msl quiet wait after close */

#define TCPS_HAVERCVDSYN(s)     ((s) >= TCPS_SYN_RECEIVED)

#define TCPS_HAVEESTABLISHED(s) ((s) >= TCPS_ESTABLISHED)

#define TCPS_HAVERCVDFIN(s)     ((s) >= TCPS_TIME_WAIT)

/*

 * TCP sequence numbers are 32 bit integers operated

 * on with modular arithmetic.  These macros can be

 * used to compare such integers.

 */

#define SEQ_LT(a,b)     ((int)((a)-(b)) < 0)

#define SEQ_LEQ(a,b)    ((int)((a)-(b)) <= 0)

#define SEQ_GT(a,b)     ((int)((a)-(b)) > 0)

#define SEQ_GEQ(a,b)    ((int)((a)-(b)) >= 0)

/*

 * Macros to initialize tcp sequence numbers for

 * send and receive from initial send and receive

 * sequence numbers.

 */

#define tcp_rcvseqinit(tp) \

     (tp)->rcv_adv = (tp)->rcv_nxt = (tp)->irs + 1

#define tcp_sendseqinit(tp) \

    (tp)->snd_una = (tp)->snd_nxt = (tp)->snd_max = (tp)->snd_up = (tp)->iss

#define TCP_ISSINCR     (125*1024)      /* increment for tcp_iss each second */

extern tcp_seq tcp_iss;                /* tcp initial send seq # */

extern const char * const tcpstates[];

#endif