xref: /freebsd/sys/netinet/tcp_fsm.h (revision 29363fb446372cb3f10bc98664e9767c53fbb457)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1982, 1986, 1993
5  *	The Regents of the University of California.
6  * All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  * 3. Neither the name of the University nor the names of its contributors
17  *    may be used to endorse or promote products derived from this software
18  *    without specific prior written permission.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30  * SUCH DAMAGE.
31  */
32 
33 #ifndef _NETINET_TCP_FSM_H_
34 #define	_NETINET_TCP_FSM_H_
35 
36 /*
37  * TCP FSM state definitions.
38  *
39  * Per RFC793, September, 1981.
40  */
41 
42 #define	TCP_NSTATES	11
43 
44 #define	TCPS_CLOSED		0	/* closed */
45 #define	TCPS_LISTEN		1	/* listening for connection */
46 #define	TCPS_SYN_SENT		2	/* active, have sent syn */
47 #define	TCPS_SYN_RECEIVED	3	/* have sent and received syn */
48 /* states < TCPS_ESTABLISHED are those where connections not established */
49 #define	TCPS_ESTABLISHED	4	/* established */
50 #define	TCPS_CLOSE_WAIT		5	/* rcvd fin, waiting for close */
51 /* states > TCPS_CLOSE_WAIT are those where user has closed */
52 #define	TCPS_FIN_WAIT_1		6	/* have closed, sent fin */
53 #define	TCPS_CLOSING		7	/* closed xchd FIN; await FIN ACK */
54 #define	TCPS_LAST_ACK		8	/* had fin and close; await FIN ACK */
55 /* states > TCPS_CLOSE_WAIT && < TCPS_FIN_WAIT_2 await ACK of FIN */
56 #define	TCPS_FIN_WAIT_2		9	/* have closed, fin is acked */
57 #define	TCPS_TIME_WAIT		10	/* in 2*msl quiet wait after close */
58 
59 #define	TCPS_HAVERCVDSYN(s)	((s) >= TCPS_SYN_RECEIVED)
60 #define	TCPS_HAVEESTABLISHED(s)	((s) >= TCPS_ESTABLISHED)
61 #define	TCPS_HAVERCVDFIN(s)	\
62     ((s) == TCPS_CLOSE_WAIT || ((s) >= TCPS_CLOSING && (s) != TCPS_FIN_WAIT_2))
63 
64 #ifdef	TCPOUTFLAGS
65 /*
66  * Flags used when sending segments in tcp_output.  Basic flags (TH_RST,
67  * TH_ACK,TH_SYN,TH_FIN) are totally determined by state, with the proviso
68  * that TH_FIN is sent only if all data queued for output is included in the
69  * segment.
70  */
71 static u_char	tcp_outflags[TCP_NSTATES] = {
72 	TH_RST|TH_ACK,		/* 0, CLOSED */
73 	0,			/* 1, LISTEN */
74 	TH_SYN,			/* 2, SYN_SENT */
75 	TH_SYN|TH_ACK,		/* 3, SYN_RECEIVED */
76 	TH_ACK,			/* 4, ESTABLISHED */
77 	TH_ACK,			/* 5, CLOSE_WAIT */
78 	TH_FIN|TH_ACK,		/* 6, FIN_WAIT_1 */
79 	TH_FIN|TH_ACK,		/* 7, CLOSING */
80 	TH_FIN|TH_ACK,		/* 8, LAST_ACK */
81 	TH_ACK,			/* 9, FIN_WAIT_2 */
82 	TH_ACK,			/* 10, TIME_WAIT */
83 };
84 #endif
85 
86 #ifdef	TCPSTATES
87 static char const * const tcpstates[] = {
88 	"CLOSED",	"LISTEN",	"SYN_SENT",	"SYN_RCVD",
89 	"ESTABLISHED",	"CLOSE_WAIT",	"FIN_WAIT_1",	"CLOSING",
90 	"LAST_ACK",	"FIN_WAIT_2",	"TIME_WAIT",
91 };
92 #endif
93 
94 #endif
95