xref: /freebsd/contrib/tcpdump/print-telnet.c (revision a90e161be323456b08b7fe13acb201536809510f)

/*	$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.
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#ifndef lint
static const char rcsid[] =
     "@(#) $Header: /tcpdump/master/tcpdump/print-telnet.c,v 1.18 2001/09/10 06:40:08 fenner Exp $";
#endif

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

#include <netinet/in.h>

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

#include "interface.h"
#include "addrtoname.h"

#define TELCMDS
#define TELOPTS
#include "telnet.h"

/* normal */
static const char *cmds[] = {
	"IS", "SEND", "INFO",
};

/* 37: Authentication */
static const char *authcmd[] = {
	"IS", "SEND", "REPLY", "NAME",
};
static const char *authtype[] = {
	"NULL", "KERBEROS_V4", "KERBEROS_V5", "SPX", "MINK",
	"SRP", "RSA", "SSL", NULL, NULL,
	"LOKI", "SSA", "KEA_SJ", "KEA_SJ_INTEG", "DSS",
	"NTLM",
};

/* 38: Encryption */
static const char *enccmd[] = {
	"IS", "SUPPORT", "REPLY", "START", "END",
	"REQUEST-START", "REQUEST-END", "END_KEYID", "DEC_KEYID",
};
static const char *enctype[] = {
	"NULL", "DES_CFB64", "DES_OFB64", "DES3_CFB64", "DES3_OFB64",
	NULL, "CAST5_40_CFB64", "CAST5_40_OFB64", "CAST128_CFB64", "CAST128_OFB64",
};

#define STR_OR_ID(x, tab) \
	(((x) < sizeof(tab)/sizeof(tab[0]) && tab[(x)]) ? tab[(x)] : numstr(x))

static char *
numstr(int x)
{
	static char buf[20];

	snprintf(buf, sizeof(buf), "%#x", x);
	return buf;
}

/* sp points to IAC byte */
static int
telnet_parse(const u_char *sp, u_int length, int print)
{
	int i, c, x;
	const u_char *osp, *p;
#define FETCH(c, sp, length) \
	do { \
		if (length < 1) \
			goto pktend; \
		TCHECK(*sp); \
		c = *sp++; \
		length--; \
	} while (0)

	osp = sp;

	FETCH(c, sp, length);
	if (c != IAC)
		goto pktend;
	FETCH(c, sp, length);
	if (c == IAC) {		/* <IAC><IAC>! */
		if (print)
			printf("IAC IAC");
		goto done;
	}

	i = c - TELCMD_FIRST;
	if (i < 0 || i > IAC - TELCMD_FIRST)
		goto pktend;

	switch (c) {
	case DONT:
	case DO:
	case WONT:
	case WILL:
	case SB:
		/* DONT/DO/WONT/WILL x */
		FETCH(x, sp, length);
		if (x >= 0 && x < NTELOPTS) {
			if (print)
				(void)printf("%s %s", telcmds[i], telopts[x]);
		} else {
			if (print)
				(void)printf("%s %#x", telcmds[i], x);
		}
		if (c != SB)
			break;
		/* IAC SB .... IAC SE */
		p = sp;
		while (length > p + 1 - sp) {
			if (p[0] == IAC && p[1] == SE)
				break;
			p++;
		}
		if (*p != IAC)
			goto pktend;

		switch (x) {
		case TELOPT_AUTHENTICATION:
			if (p <= sp)
				break;
			FETCH(c, sp, length);
			if (print)
				(void)printf(" %s", STR_OR_ID(c, authcmd));
			if (p <= sp)
				break;
			FETCH(c, sp, length);
			if (print)
				(void)printf(" %s", STR_OR_ID(c, authtype));
			break;
		case TELOPT_ENCRYPT:
			if (p <= sp)
				break;
			FETCH(c, sp, length);
			if (print)
				(void)printf(" %s", STR_OR_ID(c, enccmd));
			if (p <= sp)
				break;
			FETCH(c, sp, length);
			if (print)
				(void)printf(" %s", STR_OR_ID(c, enctype));
			break;
		default:
			if (p <= sp)
				break;
			FETCH(c, sp, length);
			if (print)
				(void)printf(" %s", STR_OR_ID(c, cmds));
			break;
		}
		while (p > sp) {
			FETCH(x, sp, length);
			if (print)
				(void)printf(" %#x", x);
		}
		/* terminating IAC SE */
		if (print)
			(void)printf(" SE");
		sp += 2;
		length -= 2;
		break;
	default:
		if (print)
			(void)printf("%s", telcmds[i]);
		goto done;
	}

done:
	return sp - osp;

trunc:
	(void)printf("[|telnet]");
pktend:
	return -1;
#undef FETCH
}

void
telnet_print(const u_char *sp, u_int length)
{
	int first = 1;
	const u_char *osp;
	int l;

	osp = sp;

	while (length > 0 && *sp == IAC) {
		l = telnet_parse(sp, length, 0);
		if (l < 0)
			break;

		/*
		 * now print it
		 */
		if (Xflag && 2 < vflag) {
			if (first)
				printf("\nTelnet:");
			hex_print_with_offset(sp, l, sp - osp);
			if (l > 8)
				printf("\n\t\t\t\t");
			else
				printf("%*s\t", (8 - l) * 3, "");
		} else
			printf("%s", (first) ? " [telnet " : ", ");

		(void)telnet_parse(sp, length, 1);
		first = 0;

		sp += l;
		length -= l;
	}
	if (!first) {
		if (Xflag && 2 < vflag)
			printf("\n");
		else
			printf("]");
	}
}