src/bin/network/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
  34 #if 0
  35 #ifndef lint
  36 static const char sccsid[] = "@(#)network.c     8.2 (Berkeley) 12/15/93";
  37 #endif
  38 #endif
  39 #include <sys/cdefs.h>
  40 __FBSDID("$FreeBSD: src/contrib/telnet/telnet/network.c,v 1.7 2003/05/04 02:54:48 obrien Exp $");
  41
  42 #include <sys/types.h>
  43 #include <sys/socket.h>
  44 #include <sys/time.h>
  45
  46 #include <errno.h>
  47 #include <stdlib.h>
  48
  49 #include <arpa/telnet.h>
  50 #include <unistd.h>
  51
  52 #include "ring.h"
  53
  54 #include "defines.h"
  55 #include "externs.h"
  56 #include "fdset.h"
  57
  58 Ring            netoring, netiring;
  59 unsigned char   netobuf[2*BUFSIZ], netibuf[BUFSIZ];
  60
  61 /*
  62  * Initialize internal network data structures.
  63  */
  64
  65 void
  66 init_network(void)
  67 {
  68     if (ring_init(&netoring, netobuf, sizeof netobuf) != 1) {
  69         exit(1);
  70     }
  71     if (ring_init(&netiring, netibuf, sizeof netibuf) != 1) {
  72         exit(1);
  73     }
  74     NetTrace = stdout;
  75 }
  76
  77
  78 /*
  79  * Check to see if any out-of-band data exists on a socket (for
  80  * Telnet "synch" processing).
  81  */
  82
  83 int
  84 stilloob(void)
  85 {
  86     static struct timeval timeout = { 0, 0 };
  87     fd_set      excepts;
  88     int value;
  89
  90     do {
  91         FD_ZERO(&excepts);
  92         FD_SET(net, &excepts);
  93         value = select(net+1, (fd_set *)0, (fd_set *)0, &excepts, &timeout);
  94     } while ((value == -1) && (errno == EINTR));
  95
  96     if (value < 0) {
  97         perror("select");
  98         (void) quit();
  99         /* NOTREACHED */
 100     }
 101     if (FD_ISSET(net, &excepts)) {
 102         return 1;
 103     } else {
 104         return 0;
 105     }
 106 }
 107
 108
 109 /*
 110  *  setneturg()
 111  *
 112  *      Sets "neturg" to the current location.
 113  */
 114
 115 void
 116 setneturg(void)
 117 {
 118     ring_mark(&netoring);
 119 }
 120
 121
 122 /*
 123  *  netflush
 124  *              Send as much data as possible to the network,
 125  *      handling requests for urgent data.
 126  *
 127  *              The return value indicates whether we did any
 128  *      useful work.
 129  */
 130
 131 int
 132 netflush(void)
 133 {
 134     int n, n1;
 135
 136 #ifdef  ENCRYPTION
 137     if (encrypt_output)
 138         ring_encrypt(&netoring, encrypt_output);
 139 #endif  /* ENCRYPTION */
 140     if ((n1 = n = ring_full_consecutive(&netoring)) > 0) {
 141         if (!ring_at_mark(&netoring)) {
 142             n = send(net, (char *)netoring.consume, n, 0); /* normal write */
 143         } else {
 144             /*
 145              * In 4.2 (and 4.3) systems, there is some question about
 146              * what byte in a sendOOB operation is the "OOB" data.
 147              * To make ourselves compatible, we only send ONE byte
 148              * out of band, the one WE THINK should be OOB (though
 149              * we really have more the TCP philosophy of urgent data
 150              * rather than the Unix philosophy of OOB data).
 151              */
 152             n = send(net, (char *)netoring.consume, 1, MSG_OOB);/* URGENT data */
 153         }
 154     }
 155     if (n < 0) {
 156         if (errno != ENOBUFS && errno != EWOULDBLOCK) {
 157             setcommandmode();
 158             perror(hostname);
 159             (void)NetClose(net);
 160             ring_clear_mark(&netoring);
 161             longjmp(peerdied, -1);
 162             /*NOTREACHED*/
 163         }
 164         n = 0;
 165     }
 166     if (netdata && n) {
 167         Dump('>', netoring.consume, n);
 168     }
 169     if (n) {
 170         ring_consumed(&netoring, n);
 171         /*
 172          * If we sent all, and more to send, then recurse to pick
 173          * up the other half.
 174          */
 175         if ((n1 == n) && ring_full_consecutive(&netoring)) {
 176             (void) netflush();
 177         }
 178         return 1;
 179     } else {
 180         return 0;
 181     }
 182 }