xref: /freebsd/sys/netinet/tcp_fsm.h (revision 29363fb446372cb3f10bc98664e9767c53fbb457)

/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * 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. 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.
 */

#ifndef _NETINET_TCP_FSM_H_
#define	_NETINET_TCP_FSM_H_

/*
 * 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 sent 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_CLOSE_WAIT || ((s) >= TCPS_CLOSING && (s) != TCPS_FIN_WAIT_2))

#ifdef	TCPOUTFLAGS
/*
 * Flags used when sending segments in tcp_output.  Basic flags (TH_RST,
 * TH_ACK,TH_SYN,TH_FIN) are totally determined by state, with the proviso
 * that TH_FIN is sent only if all data queued for output is included in the
 * segment.
 */
static u_char	tcp_outflags[TCP_NSTATES] = {
	TH_RST|TH_ACK,		/* 0, CLOSED */
	0,			/* 1, LISTEN */
	TH_SYN,			/* 2, SYN_SENT */
	TH_SYN|TH_ACK,		/* 3, SYN_RECEIVED */
	TH_ACK,			/* 4, ESTABLISHED */
	TH_ACK,			/* 5, CLOSE_WAIT */
	TH_FIN|TH_ACK,		/* 6, FIN_WAIT_1 */
	TH_FIN|TH_ACK,		/* 7, CLOSING */
	TH_FIN|TH_ACK,		/* 8, LAST_ACK */
	TH_ACK,			/* 9, FIN_WAIT_2 */
	TH_ACK,			/* 10, TIME_WAIT */
};
#endif

#ifdef	TCPSTATES
static char const * const tcpstates[] = {
	"CLOSED",	"LISTEN",	"SYN_SENT",	"SYN_RCVD",
	"ESTABLISHED",	"CLOSE_WAIT",	"FIN_WAIT_1",	"CLOSING",
	"LAST_ACK",	"FIN_WAIT_2",	"TIME_WAIT",
};
#endif

#endif