Home | History | Annotate | Line # | Download | only in talk
look_up.c revision 1.6 
      1 /*	$NetBSD: look_up.c,v 1.6 2003/08/07 11:16:05 agc 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. 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 #include <sys/cdefs.h>
     33 #ifndef lint
     34 #if 0
     35 static char sccsid[] = "@(#)look_up.c	8.1 (Berkeley) 6/6/93";
     36 #endif
     37 __RCSID("$NetBSD: look_up.c,v 1.6 2003/08/07 11:16:05 agc Exp $");
     38 #endif /* not lint */
     39 
     40 #include "talk.h"
     41 #include <errno.h>
     42 #include <unistd.h>
     43 #include "talk_ctl.h"
     44 
     45 /*
     46  * See if the local daemon has an invitation for us.
     47  */
     48 int
     49 check_local()
     50 {
     51 	CTL_RESPONSE response;
     52 	CTL_RESPONSE *rp = &response;
     53 	struct sockaddr addr;
     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 
     75 		(void)memcpy(&addr, &rp->addr.sa_family, sizeof(addr));
     76 		addr.sa_family = rp->addr.sa_family;
     77 		addr.sa_len = sizeof(addr);
     78 
     79 		errno = 0;
     80 		if (connect(sockt, &addr, sizeof(addr)) != -1)
     81 			return (1);
     82 	} while (errno == EINTR);
     83 	if (errno == ECONNREFUSED) {
     84 		/*
     85 		 * The caller gave up, but his invitation somehow
     86 		 * was not cleared. Clear it and initiate an
     87 		 * invitation. (We know there are no newer invitations,
     88 		 * the talkd works LIFO.)
     89 		 */
     90 		ctl_transact(his_machine_addr, msg, DELETE, rp);
     91 		close(sockt);
     92 		open_sockt();
     93 		return (0);
     94 	}
     95 	p_error("Unable to connect with initiator");
     96 	/*NOTREACHED*/
     97 	return (0);
     98 }
     99 
    100 /*
    101  * Look for an invitation on 'machine'
    102  */
    103 int
    104 look_for_invite(rp)
    105 	CTL_RESPONSE *rp;
    106 {
    107 	current_state = "Checking for invitation on caller's machine";
    108 	ctl_transact(his_machine_addr, msg, LOOK_UP, rp);
    109 	/* the switch is for later options, such as multiple invitations */
    110 	switch (rp->answer) {
    111 
    112 	case SUCCESS:
    113 		msg.id_num = htonl(rp->id_num);
    114 		return (1);
    115 
    116 	default:
    117 		/* there wasn't an invitation waiting for us */
    118 		return (0);
    119 	}
    120 }
    121