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. Neither the name of the University nor the names of its contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  *
  29  * @(#)network.c        8.2 (Berkeley) 12/15/93
  30  * $FreeBSD: src/crypto/telnet/telnet/network.c,v 1.2.8.2 2002/04/13 10:59:08 markm Exp $
  31  */
  32
  33 #include <sys/types.h>
  34 #include <sys/socket.h>
  35 #include <sys/time.h>
  36
  37 #include <errno.h>
  38
  39 #include <arpa/telnet.h>
  40 #include <stdlib.h>
  41 #include <unistd.h>
  42
  43 #include "ring.h"
  44
  45 #include "defines.h"
  46 #include "externs.h"
  47 #include "fdset.h"
  48
  49 Ring            netoring, netiring;
  50 unsigned char   netobuf[2*BUFSIZ], netibuf[BUFSIZ];
  51
  52 /*
  53  * Initialize internal network data structures.
  54  */
  55
  56 void
  57 init_network(void)
  58 {
  59     if (ring_init(&netoring, netobuf, sizeof netobuf) != 1) {
  60         exit(1);
  61     }
  62     if (ring_init(&netiring, netibuf, sizeof netibuf) != 1) {
  63         exit(1);
  64     }
  65     NetTrace = stdout;
  66 }
  67
  68
  69 /*
  70  * Check to see if any out-of-band data exists on a socket (for
  71  * Telnet "synch" processing).
  72  */
  73
  74 int
  75 stilloob(void)
  76 {
  77     static struct timeval timeout = { 0, 0 };
  78     fd_set      excepts;
  79     int value;
  80
  81     do {
  82         FD_ZERO(&excepts);
  83         FD_SET(net, &excepts);
  84         value = select(net+1, NULL, NULL, &excepts, &timeout);
  85     } while ((value == -1) && (errno == EINTR));
  86
  87     if (value < 0) {
  88         perror("select");
  89         (void) quit();
  90         /* NOTREACHED */
  91     }
  92     if (FD_ISSET(net, &excepts)) {
  93         return 1;
  94     } else {
  95         return 0;
  96     }
  97 }
  98
  99
 100 /*
 101  *  setneturg()
 102  *
 103  *      Sets "neturg" to the current location.
 104  */
 105
 106 void
 107 setneturg(void)
 108 {
 109     ring_mark(&netoring);
 110 }
 111
 112
 113 /*
 114  *  netflush
 115  *              Send as much data as possible to the network,
 116  *      handling requests for urgent data.
 117  *
 118  *              The return value indicates whether we did any
 119  *      useful work.
 120  */
 121
 122 int
 123 netflush(void)
 124 {
 125     int n, n1;
 126
 127 #ifdef  ENCRYPTION
 128     if (encrypt_output)
 129         ring_encrypt(&netoring, encrypt_output);
 130 #endif  /* ENCRYPTION */
 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 }