xref: /freebsd/contrib/tcpdump/print-telnet.c (revision daf1cffce2e07931f27c6c6998652e90df6ba87e)
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
53 static const char rcsid[] =
54      "@(#) $Header: /tcpdump/master/tcpdump/print-telnet.c,v 1.2.2.2 2000/01/11 06:58:28 fenner Exp $";
55 #endif
56 
57 #include <sys/param.h>
58 #include <sys/time.h>
59 #include <sys/types.h>
60 
61 #include <netinet/in.h>
62 #include <netinet/in_systm.h>
63 #include <netinet/ip.h>
64 #include <netinet/ip_var.h>
65 #include <netinet/tcp.h>
66 #include <netinet/tcpip.h>
67 
68 #define TELCMDS
69 #define TELOPTS
70 #include <arpa/telnet.h>
71 
72 #include <stdio.h>
73 #ifdef __STDC__
74 #include <stdlib.h>
75 #endif
76 #include <unistd.h>
77 #include <string.h>
78 
79 #include "interface.h"
80 #include "addrtoname.h"
81 
82 
83 #ifndef TELCMD_FIRST
84 # define TELCMD_FIRST SE
85 #endif
86 
87 void
88 telnet_print(register const u_char *sp, u_int length)
89 {
90 	static char tnet[128];
91 	register int i, c, x;
92 	register u_char *rcp;
93 	int off, first = 1;
94 	u_char	*osp;
95 
96 	off = 0;
97 	x = 0;
98 
99 	while (length > 0 && *sp == IAC) {
100 		osp = (u_char *) sp;
101 		tnet[0] = '\0';
102 
103 		c = *sp++;
104 		length--;
105 		switch (*sp) {
106 		case IAC:			/* <IAC><IAC>! */
107 			if (length > 1 && sp[1] == IAC) {
108 				(void)strcpy(tnet, "IAC IAC");
109 			} else {
110 				length = 0;
111 				continue;
112 			}
113 			break;
114 		default:
115 			c = *sp++;
116 			length--;
117 			if ((i = c - TELCMD_FIRST) < 0
118 			    || i > IAC - TELCMD_FIRST) {
119 				(void)printf("unknown: ff%02x\n", c);
120 				return;
121 			}
122 			switch (c) {
123 			case DONT:
124 			case DO:
125 			case WONT:
126 			case WILL:
127 			case SB:
128 				x = *sp++; /* option */
129 				length--;
130 				if (x >= 0 && x < NTELOPTS) {
131 					(void)sprintf(tnet, "%s %s",
132 						      telcmds[i], telopts[x]);
133 				} else {
134 					(void)sprintf(tnet, "%s %#x",
135 						      telcmds[i], x);
136 				}
137 				break;
138 			default:
139 				(void)strcpy(tnet, telcmds[i]);
140 			}
141 			if (c == SB) {
142 				c = *sp++;
143 				length--;
144 				(void)strcat(tnet, c ? " SEND" : " IS '");
145 				rcp = (u_char *) sp;
146 				i = strlen(tnet);
147 				while (length > 0 && (x = *sp++) != IAC)
148 					--length;
149 				if (x == IAC) {
150 					if (2 < vflag
151 					    && i + 16 + sp - rcp < sizeof(tnet)) {
152 						(void)strncpy(&tnet[i], rcp, sp - rcp);
153 						i += (sp - rcp) - 1;
154 						tnet[i] = '\0';
155 					} else if (i + 8 < sizeof(tnet)) {
156 						(void)strcat(&tnet[i], "...");
157 					}
158 					if (*sp++ == SE
159 					    && i + 4 < sizeof(tnet))
160 						(void)strcat(tnet, c ? " SE" : "' SE");
161 				} else if (i + 16 < sizeof(tnet)) {
162 					(void)strcat(tnet, " truncated!");
163 				}
164 			}
165 			break;
166 		}
167 		/*
168 		 * now print it
169 		 */
170 		if (Xflag && 2 < vflag) {
171 			if (first)
172 				printf("\nTelnet:\n");
173 			i = sp - osp;
174 			hex_print_with_offset(osp, i, off);
175 			off += i;
176 			if (i > 8)
177 				printf("\n\t\t\t\t%s", tnet);
178 			else
179 				printf("%*s\t%s", (8 - i) * 3, "", tnet);
180 		} else {
181 			printf("%s%s", (first) ? " [telnet " : ", ", tnet);
182 		}
183 		first = 0;
184 	}
185 	if (!first) {
186 		if (Xflag && 2 < vflag)
187 			printf("\n");
188 		else
189 			printf("]");
190 	}
191 }
192