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 1.2 2003/06/17 04:29:32 dillon 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 <unistd.h>
  46
  47 #include "ring.h"
  48
  49 #include "defines.h"
  50 #include "externs.h"
  51 #include "fdset.h"
  52
  53 Ring            netoring, netiring;
  54 unsigned char   netobuf[2*BUFSIZ], netibuf[BUFSIZ];
  55
  56 /*
  57  * Initialize internal network data structures.
  58  */
  59
  60 void
  61 init_network(void)
  62 {
  63     if (ring_init(&netoring, netobuf, sizeof netobuf) != 1) {
  64         exit(1);
  65     }
  66     if (ring_init(&netiring, netibuf, sizeof netibuf) != 1) {
  67         exit(1);
  68     }
  69     NetTrace = stdout;
  70 }
  71
  72
  73 /*
  74  * Check to see if any out-of-band data exists on a socket (for
  75  * Telnet "synch" processing).
  76  */
  77
  78 int
  79 stilloob(void)
  80 {
  81     static struct timeval timeout = { 0, 0 };
  82     fd_set      excepts;
  83     int value;
  84
  85     do {
  86         FD_ZERO(&excepts);
  87         FD_SET(net, &excepts);
  88         value = select(net+1, (fd_set *)0, (fd_set *)0, &excepts, &timeout);
  89     } while ((value == -1) && (errno == EINTR));
  90
  91     if (value < 0) {
  92         perror("select");
  93         (void) quit();
  94         /* NOTREACHED */
  95     }
  96     if (FD_ISSET(net, &excepts)) {
  97         return 1;
  98     } else {
  99         return 0;
 100     }
 101 }
 102
 103
 104 /*
 105  *  setneturg()
 106  *
 107  *      Sets "neturg" to the current location.
 108  */
 109
 110 void
 111 setneturg(void)
 112 {
 113     ring_mark(&netoring);
 114 }
 115
 116
 117 /*
 118  *  netflush
 119  *              Send as much data as possible to the network,
 120  *      handling requests for urgent data.
 121  *
 122  *              The return value indicates whether we did any
 123  *      useful work.
 124  */
 125
 126 int
 127 netflush(void)
 128 {
 129     int n, n1;
 130
 131     if ((n1 = n = ring_full_consecutive(&netoring)) > 0) {
 132         if (!ring_at_mark(&netoring)) {
 133             n = send(net, (char *)netoring.consume, n, 0); /* normal write */
 134         } else {
 135             /*
 136              * In 4.2 (and 4.3) systems, there is some question about
 137              * what byte in a sendOOB operation is the "OOB" data.
 138              * To make ourselves compatible, we only send ONE byte
 139              * out of band, the one WE THINK should be OOB (though
 140              * we really have more the TCP philosophy of urgent data
 141              * rather than the Unix philosophy of OOB data).
 142              */
 143             n = send(net, (char *)netoring.consume, 1, MSG_OOB);/* URGENT data */
 144         }
 145     }
 146     if (n < 0) {
 147         if (errno != ENOBUFS && errno != EWOULDBLOCK) {
 148             setcommandmode();
 149             perror(hostname);
 150             (void)NetClose(net);
 151             ring_clear_mark(&netoring);
 152             longjmp(peerdied, -1);
 153             /*NOTREACHED*/
 154         }
 155         n = 0;
 156     }
 157     if (netdata && n) {
 158         Dump('>', netoring.consume, n);
 159     }
 160     if (n) {
 161         ring_consumed(&netoring, n);
 162         /*
 163          * If we sent all, and more to send, then recurse to pick
 164          * up the other half.
 165          */
 166         if ((n1 == n) && ring_full_consecutive(&netoring)) {
 167             (void) netflush();
 168         }
 169         return 1;
 170     } else {
 171         return 0;
 172     }
 173 }