usr.bin/telnet/network.c

   1 /*
   2  * Copyright (c) 1988, 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  * @(#)network.c        8.2 (Berkeley) 12/15/93
  34  * $FreeBSD: src/usr.bin/telnet/network.c,v 1.2.14.1 2002/04/13 11:07:13 markm Exp $
  35  * $DragonFly: src/usr.bin/telnet/network.c,v 1.3 2007/11/25 01:28:23 swildner Exp $
  36  */
  37
  38 #include <sys/types.h>
  39 #include <sys/socket.h>
  40 #include <sys/time.h>
  41
  42 #include <errno.h>
  43
  44 #include <arpa/telnet.h>
  45 #include <stdlib.h>
  46 #include <unistd.h>
  47
  48 #include "ring.h"
  49
  50 #include "defines.h"
  51 #include "externs.h"
  52 #include "fdset.h"
  53
  54 Ring            netoring, netiring;
  55 unsigned char   netobuf[2*BUFSIZ], netibuf[BUFSIZ];
  56
  57 /*
  58  * Initialize internal network data structures.
  59  */
  60
  61 void
  62 init_network(void)
  63 {
  64     if (ring_init(&netoring, netobuf, sizeof netobuf) != 1) {
  65         exit(1);
  66     }
  67     if (ring_init(&netiring, netibuf, sizeof netibuf) != 1) {
  68         exit(1);
  69     }
  70     NetTrace = stdout;
  71 }
  72
  73
  74 /*
  75  * Check to see if any out-of-band data exists on a socket (for
  76  * Telnet "synch" processing).
  77  */
  78
  79 int
  80 stilloob(void)
  81 {
  82     static struct timeval timeout = { 0, 0 };
  83     fd_set      excepts;
  84     int value;
  85
  86     do {
  87         FD_ZERO(&excepts);
  88         FD_SET(net, &excepts);
  89         value = select(net+1, NULL, NULL, &excepts, &timeout);
  90     } while ((value == -1) && (errno == EINTR));
  91
  92     if (value < 0) {
  93         perror("select");
  94         (void) quit();
  95         /* NOTREACHED */
  96     }
  97     if (FD_ISSET(net, &excepts)) {
  98         return 1;
  99     } else {
 100         return 0;
 101     }
 102 }
 103
 104
 105 /*
 106  *  setneturg()
 107  *
 108  *      Sets "neturg" to the current location.
 109  */
 110
 111 void
 112 setneturg(void)
 113 {
 114     ring_mark(&netoring);
 115 }
 116
 117
 118 /*
 119  *  netflush
 120  *              Send as much data as possible to the network,
 121  *      handling requests for urgent data.
 122  *
 123  *              The return value indicates whether we did any
 124  *      useful work.
 125  */
 126
 127 int
 128 netflush(void)
 129 {
 130     int n, n1;
 131
 132     if ((n1 = n = ring_full_consecutive(&netoring)) > 0) {
 133         if (!ring_at_mark(&netoring)) {
 134             n = send(net, (char *)netoring.consume, n, 0); /* normal write */
 135         } else {
 136             /*
 137              * In 4.2 (and 4.3) systems, there is some question about
 138              * what byte in a sendOOB operation is the "OOB" data.
 139              * To make ourselves compatible, we only send ONE byte
 140              * out of band, the one WE THINK should be OOB (though
 141              * we really have more the TCP philosophy of urgent data
 142              * rather than the Unix philosophy of OOB data).
 143              */
 144             n = send(net, (char *)netoring.consume, 1, MSG_OOB);/* URGENT data */
 145         }
 146     }
 147     if (n < 0) {
 148         if (errno != ENOBUFS && errno != EWOULDBLOCK) {
 149             setcommandmode();
 150             perror(hostname);
 151             (void)NetClose(net);
 152             ring_clear_mark(&netoring);
 153             longjmp(peerdied, -1);
 154             /*NOTREACHED*/
 155         }
 156         n = 0;
 157     }
 158     if (netdata && n) {
 159         Dump('>', netoring.consume, n);
 160     }
 161     if (n) {
 162         ring_consumed(&netoring, n);
 163         /*
 164          * If we sent all, and more to send, then recurse to pick
 165          * up the other half.
 166          */
 167         if ((n1 == n) && ring_full_consecutive(&netoring)) {
 168             (void) netflush();
 169         }
 170         return 1;
 171     } else {
 172         return 0;
 173     }
 174 }