1/*	$NetBSD: print-telnet.c,v 1.2 1999/10/11 12:40:12 sjg Exp $ 	*/
2
3/*-
4 * Copyright (c) 1997, 1998 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Simon J. Gerraty.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 * 3. All advertising materials mentioning features or use of this software
19 *    must display the following acknowledgement:
20 *        This product includes software developed by the NetBSD
21 *        Foundation, Inc. and its contributors.
22 * 4. Neither the name of The NetBSD Foundation nor the names of its
23 *    contributors may be used to endorse or promote products derived
24 *    from this software without specific prior written permission.
25 *
26 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
27 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
28 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
29 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
30 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
31 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
32 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
33 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
34 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
35 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
36 * POSSIBILITY OF SUCH DAMAGE.
37 */
38/*
39 *      @(#)Copyright (c) 1994, Simon J. Gerraty.
40 *
41 *      This is free software.  It comes with NO WARRANTY.
42 *      Permission to use, modify and distribute this source code
43 *      is granted subject to the following conditions.
44 *      1/ that the above copyright notice and this notice
45 *      are preserved in all copies.
46 */
47
48#ifdef HAVE_CONFIG_H
49#include "config.h"
50#endif
51
52#ifndef lint
53static const char rcsid[] _U_ =
54     "@(#) $Header: /tcpdump/master/tcpdump/print-telnet.c,v 1.24 2003-12-29 11:05:10 hannes Exp $";
55#endif
56
57#include <tcpdump-stdinc.h>
58
59#include <stdio.h>
60#include <stdlib.h>
61#include <string.h>
62
63#include "interface.h"
64#include "addrtoname.h"
65
66#define TELCMDS
67#define TELOPTS
68#include "telnet.h"
69
70/* normal */
71static const char *cmds[] = {
72	"IS", "SEND", "INFO",
73};
74
75/* 37: Authentication */
76static const char *authcmd[] = {
77	"IS", "SEND", "REPLY", "NAME",
78};
79static const char *authtype[] = {
80	"NULL", "KERBEROS_V4", "KERBEROS_V5", "SPX", "MINK",
81	"SRP", "RSA", "SSL", NULL, NULL,
82	"LOKI", "SSA", "KEA_SJ", "KEA_SJ_INTEG", "DSS",
83	"NTLM",
84};
85
86/* 38: Encryption */
87static const char *enccmd[] = {
88	"IS", "SUPPORT", "REPLY", "START", "END",
89	"REQUEST-START", "REQUEST-END", "END_KEYID", "DEC_KEYID",
90};
91static const char *enctype[] = {
92	"NULL", "DES_CFB64", "DES_OFB64", "DES3_CFB64", "DES3_OFB64",
93	NULL, "CAST5_40_CFB64", "CAST5_40_OFB64", "CAST128_CFB64", "CAST128_OFB64",
94};
95
96#define STR_OR_ID(x, tab) \
97	(((x) < sizeof(tab)/sizeof(tab[0]) && tab[(x)]) ? tab[(x)] : numstr(x))
98
99static char *
100numstr(int x)
101{
102	static char buf[20];
103
104	snprintf(buf, sizeof(buf), "%#x", x);
105	return buf;
106}
107
108/* sp points to IAC byte */
109static int
110telnet_parse(const u_char *sp, u_int length, int print)
111{
112	int i, x;
113	u_int c;
114	const u_char *osp, *p;
115#define FETCH(c, sp, length) \
116	do { \
117		if (length < 1) \
118			goto pktend; \
119		TCHECK(*sp); \
120		c = *sp++; \
121		length--; \
122	} while (0)
123
124	osp = sp;
125
126	FETCH(c, sp, length);
127	if (c != IAC)
128		goto pktend;
129	FETCH(c, sp, length);
130	if (c == IAC) {		/* <IAC><IAC>! */
131		if (print)
132			printf("IAC IAC");
133		goto done;
134	}
135
136	i = c - TELCMD_FIRST;
137	if (i < 0 || i > IAC - TELCMD_FIRST)
138		goto pktend;
139
140	switch (c) {
141	case DONT:
142	case DO:
143	case WONT:
144	case WILL:
145	case SB:
146		/* DONT/DO/WONT/WILL x */
147		FETCH(x, sp, length);
148		if (x >= 0 && x < NTELOPTS) {
149			if (print)
150				(void)printf("%s %s", telcmds[i], telopts[x]);
151		} else {
152			if (print)
153				(void)printf("%s %#x", telcmds[i], x);
154		}
155		if (c != SB)
156			break;
157		/* IAC SB .... IAC SE */
158		p = sp;
159		while (length > (u_int)(p + 1 - sp)) {
160			if (p[0] == IAC && p[1] == SE)
161				break;
162			p++;
163		}
164		if (*p != IAC)
165			goto pktend;
166
167		switch (x) {
168		case TELOPT_AUTHENTICATION:
169			if (p <= sp)
170				break;
171			FETCH(c, sp, length);
172			if (print)
173				(void)printf(" %s", STR_OR_ID(c, authcmd));
174			if (p <= sp)
175				break;
176			FETCH(c, sp, length);
177			if (print)
178				(void)printf(" %s", STR_OR_ID(c, authtype));
179			break;
180		case TELOPT_ENCRYPT:
181			if (p <= sp)
182				break;
183			FETCH(c, sp, length);
184			if (print)
185				(void)printf(" %s", STR_OR_ID(c, enccmd));
186			if (p <= sp)
187				break;
188			FETCH(c, sp, length);
189			if (print)
190				(void)printf(" %s", STR_OR_ID(c, enctype));
191			break;
192		default:
193			if (p <= sp)
194				break;
195			FETCH(c, sp, length);
196			if (print)
197				(void)printf(" %s", STR_OR_ID(c, cmds));
198			break;
199		}
200		while (p > sp) {
201			FETCH(x, sp, length);
202			if (print)
203				(void)printf(" %#x", x);
204		}
205		/* terminating IAC SE */
206		if (print)
207			(void)printf(" SE");
208		sp += 2;
209		length -= 2;
210		break;
211	default:
212		if (print)
213			(void)printf("%s", telcmds[i]);
214		goto done;
215	}
216
217done:
218	return sp - osp;
219
220trunc:
221	(void)printf("[|telnet]");
222pktend:
223	return -1;
224#undef FETCH
225}
226
227void
228telnet_print(const u_char *sp, u_int length)
229{
230	int first = 1;
231	const u_char *osp;
232	int l;
233
234	osp = sp;
235
236	while (length > 0 && *sp == IAC) {
237		l = telnet_parse(sp, length, 0);
238		if (l < 0)
239			break;
240
241		/*
242		 * now print it
243		 */
244		if (Xflag && 2 < vflag) {
245			if (first)
246				printf("\nTelnet:");
247			hex_print_with_offset("\n", sp, l, sp - osp);
248			if (l > 8)
249				printf("\n\t\t\t\t");
250			else
251				printf("%*s\t", (8 - l) * 3, "");
252		} else
253			printf("%s", (first) ? " [telnet " : ", ");
254
255		(void)telnet_parse(sp, length, 1);
256		first = 0;
257
258		sp += l;
259		length -= l;
260	}
261	if (!first) {
262		if (Xflag && 2 < vflag)
263			printf("\n");
264		else
265			printf("]");
266	}
267}
268