look_up.c revision 50477 
1/*
2 * Copyright (c) 1983, 1993
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 *    must display the following acknowledgement:
15 *	This product includes software developed by the University of
16 *	California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 *    may be used to endorse or promote products derived from this software
19 *    without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34#ifndef lint
35#if 0
36static char sccsid[] = "@(#)look_up.c	8.1 (Berkeley) 6/6/93";
37#endif
38static const char rcsid[] =
39  "$FreeBSD: head/usr.bin/talk/look_up.c 50477 1999-08-28 01:08:13Z peter $";
40#endif /* not lint */
41
42#include <errno.h>
43#include <sys/types.h>
44#include <sys/socket.h>
45#include <protocols/talkd.h>
46#include "talk_ctl.h"
47#include "talk.h"
48
49/*
50 * See if the local daemon has an invitation for us.
51 */
52int
53check_local()
54{
55	CTL_RESPONSE response;
56	register CTL_RESPONSE *rp = &response;
57
58	/* the rest of msg was set up in get_names */
59#ifdef MSG_EOR
60	/* copy new style sockaddr to old, swap family (short in old) */
61	msg.ctl_addr = *(struct osockaddr *)&ctl_addr;
62	msg.ctl_addr.sa_family = htons(ctl_addr.sin_family);
63#else
64	msg.ctl_addr = *(struct sockaddr *)&ctl_addr;
65#endif
66	/* must be initiating a talk */
67	if (!look_for_invite(rp))
68		return (0);
69	/*
70	 * There was an invitation waiting for us,
71	 * so connect with the other (hopefully waiting) party
72	 */
73	current_state = "Waiting to connect with caller";
74	do {
75		if (rp->addr.sa_family != AF_INET)
76			p_error("Response uses invalid network address");
77		errno = 0;
78		if (connect(sockt,
79		    (struct sockaddr *)&rp->addr, sizeof (rp->addr)) != -1)
80			return (1);
81	} while (errno == EINTR);
82	if (errno == ECONNREFUSED) {
83		/*
84		 * The caller gave up, but his invitation somehow
85		 * was not cleared. Clear it and initiate an
86		 * invitation. (We know there are no newer invitations,
87		 * the talkd works LIFO.)
88		 */
89		ctl_transact(his_machine_addr, msg, DELETE, rp);
90		close(sockt);
91		open_sockt();
92		return (0);
93	}
94	p_error("Unable to connect with initiator");
95	/*NOTREACHED*/
96	return (0);
97}
98
99/*
100 * Look for an invitation on 'machine'
101 */
102int
103look_for_invite(rp)
104	CTL_RESPONSE *rp;
105{
106	struct in_addr machine_addr;
107
108	current_state = "Checking for invitation on caller's machine";
109	ctl_transact(his_machine_addr, msg, LOOK_UP, rp);
110	/* the switch is for later options, such as multiple invitations */
111	switch (rp->answer) {
112
113	case SUCCESS:
114		msg.id_num = htonl(rp->id_num);
115		return (1);
116
117	default:
118		/* there wasn't an invitation waiting for us */
119		return (0);
120	}
121}
122