look_up.c revision 8874 
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 */
49check_local()
50{
51	CTL_RESPONSE response;
52	register CTL_RESPONSE *rp = &response;
53
54	/* the rest of msg was set up in get_names */
55#ifdef MSG_EOR
56	/* copy new style sockaddr to old, swap family (short in old) */
57	msg.ctl_addr = *(struct osockaddr *)&ctl_addr;
58	msg.ctl_addr.sa_family = htons(ctl_addr.sin_family);
59#else
60	msg.ctl_addr = *(struct sockaddr *)&ctl_addr;
61#endif
62	/* must be initiating a talk */
63	if (!look_for_invite(rp))
64		return (0);
65	/*
66	 * There was an invitation waiting for us,
67	 * so connect with the other (hopefully waiting) party
68	 */
69	current_state = "Waiting to connect with caller";
70	do {
71		if (rp->addr.sa_family != AF_INET)
72			p_error("Response uses invalid network address");
73		errno = 0;
74		if (connect(sockt,
75		    (struct sockaddr *)&rp->addr, sizeof (rp->addr)) != -1)
76			return (1);
77	} while (errno == EINTR);
78	if (errno == ECONNREFUSED) {
79		/*
80		 * The caller gave up, but his invitation somehow
81		 * was not cleared. Clear it and initiate an
82		 * invitation. (We know there are no newer invitations,
83		 * the talkd works LIFO.)
84		 */
85		ctl_transact(his_machine_addr, msg, DELETE, rp);
86		close(sockt);
87		open_sockt();
88		return (0);
89	}
90	p_error("Unable to connect with initiator");
91	/*NOTREACHED*/
92}
93
94/*
95 * Look for an invitation on 'machine'
96 */
97look_for_invite(rp)
98	CTL_RESPONSE *rp;
99{
100	struct in_addr machine_addr;
101
102	current_state = "Checking for invitation on caller's machine";
103	ctl_transact(his_machine_addr, msg, LOOK_UP, rp);
104	/* the switch is for later options, such as multiple invitations */
105	switch (rp->answer) {
106
107	case SUCCESS:
108		msg.id_num = htonl(rp->id_num);
109		return (1);
110
111	default:
112		/* there wasn't an invitation waiting for us */
113		return (0);
114	}
115}
116