look_up.c revision 14443 
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
35static char sccsid[] = "@(#)look_up.c	8.1 (Berkeley) 6/6/93";
36#endif /* not lint */
37
38#include <sys/types.h>
39#include <sys/socket.h>
40#include <netinet/in.h>
41#include <protocols/talkd.h>
42#include <errno.h>
43#include "talk_ctl.h"
44#include "talk.h"
45
46/*
47 * See if the local daemon has an invitation for us.
48 */
49int
50check_local()
51{
52	CTL_RESPONSE response;
53	register CTL_RESPONSE *rp = &response;
54
55	/* the rest of msg was set up in get_names */
56#ifdef MSG_EOR
57	/* copy new style sockaddr to old, swap family (short in old) */
58	msg.ctl_addr = *(struct osockaddr *)&ctl_addr;
59	msg.ctl_addr.sa_family = htons(ctl_addr.sin_family);
60#else
61	msg.ctl_addr = *(struct sockaddr *)&ctl_addr;
62#endif
63	/* must be initiating a talk */
64	if (!look_for_invite(rp))
65		return (0);
66	/*
67	 * There was an invitation waiting for us,
68	 * so connect with the other (hopefully waiting) party
69	 */
70	current_state = "Waiting to connect with caller";
71	do {
72		if (rp->addr.sa_family != AF_INET)
73			p_error("Response uses invalid network address");
74		errno = 0;
75		if (connect(sockt,
76		    (struct sockaddr *)&rp->addr, sizeof (rp->addr)) != -1)
77			return (1);
78	} while (errno == EINTR);
79	if (errno == ECONNREFUSED) {
80		/*
81		 * The caller gave up, but his invitation somehow
82		 * was not cleared. Clear it and initiate an
83		 * invitation. (We know there are no newer invitations,
84		 * the talkd works LIFO.)
85		 */
86		ctl_transact(his_machine_addr, msg, DELETE, rp);
87		close(sockt);
88		open_sockt();
89		return (0);
90	}
91	p_error("Unable to connect with initiator");
92	/*NOTREACHED*/
93	return (0);
94}
95
96/*
97 * Look for an invitation on 'machine'
98 */
99int
100look_for_invite(rp)
101	CTL_RESPONSE *rp;
102{
103	struct in_addr machine_addr;
104
105	current_state = "Checking for invitation on caller's machine";
106	ctl_transact(his_machine_addr, msg, LOOK_UP, rp);
107	/* the switch is for later options, such as multiple invitations */
108	switch (rp->answer) {
109
110	case SUCCESS:
111		msg.id_num = htonl(rp->id_num);
112		return (1);
113
114	default:
115		/* there wasn't an invitation waiting for us */
116		return (0);
117	}
118}
119