1/*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1983, 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
32#ifndef _PROTOCOLS_TALKD_H_
33#define	_PROTOCOLS_TALKD_H_
34
35/*
36 * This describes the protocol used by the talk server and clients.
37 *
38 * The talk server acts a repository of invitations, responding to
39 * requests by clients wishing to rendezvous for the purpose of
40 * holding a conversation.  In normal operation, a client, the caller,
41 * initiates a rendezvous by sending a CTL_MSG to the server of
42 * type LOOK_UP.  This causes the server to search its invitation
43 * tables to check if an invitation currently exists for the caller
44 * (to speak to the callee specified in the message).  If the lookup
45 * fails, the caller then sends an ANNOUNCE message causing the server
46 * to broadcast an announcement on the callee's login ports requesting
47 * contact.  When the callee responds, the local server uses the
48 * recorded invitation to respond with the appropriate rendezvous
49 * address and the caller and callee client programs establish a
50 * stream connection through which the conversation takes place.
51 */
52
53/*
54 * The talk protocol embeds a 4.3BSD sockaddr.  Define our own version
55 * rather then relying on namespace pollution in kernel headers.
56 */
57struct tsockaddr {
58	unsigned short sa_family;
59	char	sa_data[14];
60};
61
62/*
63 * Client->server request message format.
64 */
65typedef struct {
66	u_char	vers;		/* protocol version */
67	u_char	type;		/* request type, see below */
68	u_char	answer;		/* not used */
69	u_char	pad;
70	u_int32_t	id_num;		/* message id */
71	struct	tsockaddr addr;		/* old (4.3) style */
72	struct	tsockaddr ctl_addr;	/* old (4.3) style */
73	int32_t	pid;		/* caller's process id */
74#define	NAME_SIZE	12
75	char	l_name[NAME_SIZE];/* caller's name */
76	char	r_name[NAME_SIZE];/* callee's name */
77#define	TTY_SIZE	16
78	char	r_tty[TTY_SIZE];/* callee's tty name */
79} CTL_MSG;
80
81/*
82 * Server->client response message format.
83 */
84typedef struct {
85	u_char	vers;		/* protocol version */
86	u_char	type;		/* type of request message, see below */
87	u_char	answer;		/* respose to request message, see below */
88	u_char	pad;
89	u_int32_t	id_num;		/* message id */
90	struct	tsockaddr addr;	/* address for establishing conversation */
91} CTL_RESPONSE;
92
93#define	TALK_VERSION	1		/* protocol version */
94
95/* message type values */
96#define LEAVE_INVITE	0	/* leave invitation with server */
97#define LOOK_UP		1	/* check for invitation by callee */
98#define DELETE		2	/* delete invitation by caller */
99#define ANNOUNCE	3	/* announce invitation by caller */
100
101/* answer values */
102#define SUCCESS		0	/* operation completed properly */
103#define NOT_HERE	1	/* callee not logged in */
104#define FAILED		2	/* operation failed for unexplained reason */
105#define MACHINE_UNKNOWN	3	/* caller's machine name unknown */
106#define PERMISSION_DENIED 4	/* callee's tty doesn't permit announce */
107#define UNKNOWN_REQUEST	5	/* request has invalid type value */
108#define	BADVERSION	6	/* request has invalid protocol version */
109#define	BADADDR		7	/* request has invalid addr value */
110#define	BADCTLADDR	8	/* request has invalid ctl_addr value */
111
112/*
113 * Operational parameters.
114 */
115#define MAX_LIFE	60	/* max time daemon saves invitations */
116/* RING_WAIT should be 10's of seconds less than MAX_LIFE */
117#define RING_WAIT	30	/* time to wait before resending invitation */
118
119#endif /* !_TALKD_H_ */
120