_telnet.c

This directory contains source code for tcpdump, a tool for network monitoring and data acquisition

/*      $NetBSD: print-telnet.c,v 1.2 1999/10/11 12:40:12 sjg Exp $     */

/*-
 * Copyright (c) 1997, 1998 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Simon J. Gerraty.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *        This product includes software developed by the NetBSD
 *        Foundation, Inc. and its contributors.
 * 4. Neither the name of The NetBSD Foundation nor the names of its
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */
/*
 *      @(#)Copyright (c) 1994, Simon J. Gerraty.
 *      
 *      This is free software.  It comes with NO WARRANTY.
 *      Permission to use, modify and distribute this source code 
 *      is granted subject to the following conditions.
 *      1/ that the above copyright notice and this notice 
 *      are preserved in all copies.
 */

#if 0
static const char rcsid[] =
"@(#) $Header: /tcpdump/master/tcpdump/print-telnet.c,v 1.2.2.2 2000/01/11 06:58:28 fenner Exp $";
#endif

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>

#include <sys/param.h>
#include <sys/time.h>
#include <sys/types.h>

#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/ip_var.h>
#include <netinet/tcp.h>
#include <netinet/tcpip.h>

#define TELCMDS
#define TELOPTS
#include <arpa/telnet.h>

#include "interfac.h"
#include "a2name.h"

#ifndef TELCMD_FIRST
#define TELCMD_FIRST SE
#endif

void telnet_print (const u_char *sp, u_int length)
{
  static char tnet[128];
  u_char *rcp, *osp;
  int    off, first = 1;
  int    i, c, x;

  off = 0;
  x   = 0;

  while (length > 0 && *sp == IAC)
  {
    osp = (u_char *) sp;
    tnet[0] = '\0';

    c = *sp++;
    length--;
    switch (*sp)
    {
      case IAC:              /* <IAC><IAC>! */
           if (length > 1 && sp[1] == IAC)
           {
             strcpy (tnet, "IAC IAC");
           }
           else
           {
             length = 0;
             continue;
           }
           break;

      default:
           c = *sp++;
           length--;
           if ((i = c - TELCMD_FIRST) < 0 || i > IAC - TELCMD_FIRST)
           {
             PRINTF ("unknown: ff%02x\n", c);
             return;
           }
           switch (c)
           {
             case DONT:
             case DO:
             case WONT:
             case WILL:
             case SB:
                  x = *sp++;    /* option */
                  length--;
                  if (x >= 0 && x < NTELOPTS)
                       sprintf (tnet, "%s %s", telcmds[i], telopts[x]);
                  else sprintf (tnet, "%s %#x",telcmds[i], x);
                  break;
             default:
                  strcpy (tnet, telcmds[i]);
           }
           if (c == SB)
           {
             c = *sp++;
             length--;
             strcat (tnet, c ? " SEND" : " IS '");
             rcp = (u_char *) sp;
             i = strlen (tnet);
             while (length > 0 && (x = *sp++) != IAC)
               --length;
             if (x == IAC)
             {
               if (2 < vflag && i + 16 + sp - rcp < sizeof(tnet))
               {
                 strncpy (&tnet[i], rcp, sp - rcp);
                 i += (sp - rcp) - 1;
                 tnet[i] = '\0';
               }
               else if (i + 8 < sizeof(tnet))
                 strcat (&tnet[i], "...");

               if (*sp++ == SE && i + 4 < sizeof(tnet))
                 strcat (tnet, c ? " SE" : "' SE");
             }
             else if (i + 16 < sizeof(tnet))
               strcat (tnet, " truncated!");
           }
           break;
    }
    /*
     * now print it
     */
    if (xaflag && 2 < vflag)
    {
      if (first)
         PUTS ("\nTelnet:\n");
      i = sp - osp;
      hex_print_with_offset (osp, i, off);
      off += i;
      if (i > 8)
           PRINTF ("\n\t\t\t\t%s", tnet);
      else PRINTF ("%*s\t%s", (8 - i) * 3, "", tnet);
    }
    else
      PRINTF ("%s%s", (first) ? " [telnet " : ", ", tnet);

    first = 0;
  }
  if (!first)
  {
    if (xaflag && 2 < vflag)
         PUTCHAR ('\n');
    else PUTCHAR (']');
  }
}