usr.bin/talk/look_up.c

   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  * @(#)look_up.c        8.1 (Berkeley) 6/6/93
  34  * $FreeBSD: src/usr.bin/talk/look_up.c,v 1.5 1999/08/28 01:06:14 peter Exp $
  35  * $DragonFly: src/usr.bin/talk/look_up.c,v 1.5 2008/10/16 01:52:33 swildner Exp $
  36  */
  37
  38 #include <sys/param.h>
  39 #include <sys/socket.h>
  40 #include <protocols/talkd.h>
  41 #include <errno.h>
  42 #include "talk_ctl.h"
  43 #include "talk.h"
  44
  45 /*
  46  * See if the local daemon has an invitation for us.
  47  */
  48 int
  49 check_local(void)
  50 {
  51         CTL_RESPONSE response;
  52         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         return (0);
  93 }
  94
  95 /*
  96  * Look for an invitation on 'machine'
  97  */
  98 int
  99 look_for_invite(CTL_RESPONSE *rp)
 100 {
 101         struct in_addr machine_addr;
 102
 103         current_state = "Checking for invitation on caller's machine";
 104         ctl_transact(his_machine_addr, msg, LOOK_UP, rp);
 105         /* the switch is for later options, such as multiple invitations */
 106         switch (rp->answer) {
 107
 108         case SUCCESS:
 109                 msg.id_num = htonl(rp->id_num);
 110                 return (1);
 111
 112         default:
 113                 /* there wasn't an invitation waiting for us */
 114                 return (0);
 115         }
 116 }