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look_up.c revision 1.5 
      1 /*	$NetBSD: look_up.c,v 1.5 2001/09/27 14:43:31 christos Exp $	*/
      2 
      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. All advertising materials mentioning features or use of this software
     16  *    must display the following acknowledgement:
     17  *	This product includes software developed by the University of
     18  *	California, Berkeley and its contributors.
     19  * 4. Neither the name of the University nor the names of its contributors
     20  *    may be used to endorse or promote products derived from this software
     21  *    without specific prior written permission.
     22  *
     23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     33  * SUCH DAMAGE.
     34  */
     35 
     36 #include <sys/cdefs.h>
     37 #ifndef lint
     38 #if 0
     39 static char sccsid[] = "@(#)look_up.c	8.1 (Berkeley) 6/6/93";
     40 #endif
     41 __RCSID("$NetBSD: look_up.c,v 1.5 2001/09/27 14:43:31 christos Exp $");
     42 #endif /* not lint */
     43 
     44 #include "talk.h"
     45 #include <errno.h>
     46 #include <unistd.h>
     47 #include "talk_ctl.h"
     48 
     49 /*
     50  * See if the local daemon has an invitation for us.
     51  */
     52 int
     53 check_local()
     54 {
     55 	CTL_RESPONSE response;
     56 	CTL_RESPONSE *rp = &response;
     57 	struct sockaddr addr;
     58 
     59 	/* the rest of msg was set up in get_names */
     60 #ifdef MSG_EOR
     61 	/* copy new style sockaddr to old, swap family (short in old) */
     62 	msg.ctl_addr = *(struct osockaddr *)&ctl_addr;
     63 	msg.ctl_addr.sa_family = htons(ctl_addr.sin_family);
     64 #else
     65 	msg.ctl_addr = *(struct sockaddr *)&ctl_addr;
     66 #endif
     67 	/* must be initiating a talk */
     68 	if (!look_for_invite(rp))
     69 		return (0);
     70 	/*
     71 	 * There was an invitation waiting for us,
     72 	 * so connect with the other (hopefully waiting) party
     73 	 */
     74 	current_state = "Waiting to connect with caller";
     75 	do {
     76 		if (rp->addr.sa_family != AF_INET)
     77 			p_error("Response uses invalid network address");
     78 
     79 		(void)memcpy(&addr, &rp->addr.sa_family, sizeof(addr));
     80 		addr.sa_family = rp->addr.sa_family;
     81 		addr.sa_len = sizeof(addr);
     82 
     83 		errno = 0;
     84 		if (connect(sockt, &addr, sizeof(addr)) != -1)
     85 			return (1);
     86 	} while (errno == EINTR);
     87 	if (errno == ECONNREFUSED) {
     88 		/*
     89 		 * The caller gave up, but his invitation somehow
     90 		 * was not cleared. Clear it and initiate an
     91 		 * invitation. (We know there are no newer invitations,
     92 		 * the talkd works LIFO.)
     93 		 */
     94 		ctl_transact(his_machine_addr, msg, DELETE, rp);
     95 		close(sockt);
     96 		open_sockt();
     97 		return (0);
     98 	}
     99 	p_error("Unable to connect with initiator");
    100 	/*NOTREACHED*/
    101 	return (0);
    102 }
    103 
    104 /*
    105  * Look for an invitation on 'machine'
    106  */
    107 int
    108 look_for_invite(rp)
    109 	CTL_RESPONSE *rp;
    110 {
    111 	current_state = "Checking for invitation on caller's machine";
    112 	ctl_transact(his_machine_addr, msg, LOOK_UP, rp);
    113 	/* the switch is for later options, such as multiple invitations */
    114 	switch (rp->answer) {
    115 
    116 	case SUCCESS:
    117 		msg.id_num = htonl(rp->id_num);
    118 		return (1);
    119 
    120 	default:
    121 		/* there wasn't an invitation waiting for us */
    122 		return (0);
    123 	}
    124 }
    125