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[tcpdump] / print-telnet.c
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 /* \summary: Telnet option printer */
49
50 #ifdef HAVE_CONFIG_H
51 #include "config.h"
52 #endif
53
54 #include "netdissect-stdinc.h"
55
56 #include <stdio.h>
57
58 #include "netdissect.h"
59 #include "extract.h"
60
61 static const char tstr[] = " [|telnet]";
62
63 #define TELCMDS
64 #define TELOPTS
65
66 /* NetBSD: telnet.h,v 1.9 2001/06/11 01:50:50 wiz Exp */
67
68 /*
69 * Definitions for the TELNET protocol.
70 */
71 #define IAC 255 /* interpret as command: */
72 #define DONT 254 /* you are not to use option */
73 #define DO 253 /* please, you use option */
74 #define WONT 252 /* I won't use option */
75 #define WILL 251 /* I will use option */
76 #define SB 250 /* interpret as subnegotiation */
77 #define GA 249 /* you may reverse the line */
78 #define EL 248 /* erase the current line */
79 #define EC 247 /* erase the current character */
80 #define AYT 246 /* are you there */
81 #define AO 245 /* abort output--but let prog finish */
82 #define IP 244 /* interrupt process--permanently */
83 #define BREAK 243 /* break */
84 #define DM 242 /* data mark--for connect. cleaning */
85 #define NOP 241 /* nop */
86 #define SE 240 /* end sub negotiation */
87 #define EOR 239 /* end of record (transparent mode) */
88 #define ABORT 238 /* Abort process */
89 #define SUSP 237 /* Suspend process */
90 #define xEOF 236 /* End of file: EOF is already used... */
91
92 #define SYNCH 242 /* for telfunc calls */
93
94 #ifdef TELCMDS
95 static const char *telcmds[] = {
96 "EOF", "SUSP", "ABORT", "EOR",
97 "SE", "NOP", "DMARK", "BRK", "IP", "AO", "AYT", "EC",
98 "EL", "GA", "SB", "WILL", "WONT", "DO", "DONT", "IAC", 0,
99 };
100 #else
101 extern char *telcmds[];
102 #endif
103
104 #define TELCMD_FIRST xEOF
105 #define TELCMD_LAST IAC
106 #define TELCMD_OK(x) ((unsigned int)(x) <= TELCMD_LAST && \
107 (unsigned int)(x) >= TELCMD_FIRST)
108 #define TELCMD(x) telcmds[(x)-TELCMD_FIRST]
109
110 /* telnet options */
111 #define TELOPT_BINARY 0 /* 8-bit data path */
112 #define TELOPT_ECHO 1 /* echo */
113 #define TELOPT_RCP 2 /* prepare to reconnect */
114 #define TELOPT_SGA 3 /* suppress go ahead */
115 #define TELOPT_NAMS 4 /* approximate message size */
116 #define TELOPT_STATUS 5 /* give status */
117 #define TELOPT_TM 6 /* timing mark */
118 #define TELOPT_RCTE 7 /* remote controlled transmission and echo */
119 #define TELOPT_NAOL 8 /* negotiate about output line width */
120 #define TELOPT_NAOP 9 /* negotiate about output page size */
121 #define TELOPT_NAOCRD 10 /* negotiate about CR disposition */
122 #define TELOPT_NAOHTS 11 /* negotiate about horizontal tabstops */
123 #define TELOPT_NAOHTD 12 /* negotiate about horizontal tab disposition */
124 #define TELOPT_NAOFFD 13 /* negotiate about formfeed disposition */
125 #define TELOPT_NAOVTS 14 /* negotiate about vertical tab stops */
126 #define TELOPT_NAOVTD 15 /* negotiate about vertical tab disposition */
127 #define TELOPT_NAOLFD 16 /* negotiate about output LF disposition */
128 #define TELOPT_XASCII 17 /* extended ascic character set */
129 #define TELOPT_LOGOUT 18 /* force logout */
130 #define TELOPT_BM 19 /* byte macro */
131 #define TELOPT_DET 20 /* data entry terminal */
132 #define TELOPT_SUPDUP 21 /* supdup protocol */
133 #define TELOPT_SUPDUPOUTPUT 22 /* supdup output */
134 #define TELOPT_SNDLOC 23 /* send location */
135 #define TELOPT_TTYPE 24 /* terminal type */
136 #define TELOPT_EOR 25 /* end or record */
137 #define TELOPT_TUID 26 /* TACACS user identification */
138 #define TELOPT_OUTMRK 27 /* output marking */
139 #define TELOPT_TTYLOC 28 /* terminal location number */
140 #define TELOPT_3270REGIME 29 /* 3270 regime */
141 #define TELOPT_X3PAD 30 /* X.3 PAD */
142 #define TELOPT_NAWS 31 /* window size */
143 #define TELOPT_TSPEED 32 /* terminal speed */
144 #define TELOPT_LFLOW 33 /* remote flow control */
145 #define TELOPT_LINEMODE 34 /* Linemode option */
146 #define TELOPT_XDISPLOC 35 /* X Display Location */
147 #define TELOPT_OLD_ENVIRON 36 /* Old - Environment variables */
148 #define TELOPT_AUTHENTICATION 37/* Authenticate */
149 #define TELOPT_ENCRYPT 38 /* Encryption option */
150 #define TELOPT_NEW_ENVIRON 39 /* New - Environment variables */
151 #define TELOPT_EXOPL 255 /* extended-options-list */
152
153
154 #define NTELOPTS (1+TELOPT_NEW_ENVIRON)
155 #ifdef TELOPTS
156 static const char *telopts[NTELOPTS+1] = {
157 "BINARY", "ECHO", "RCP", "SUPPRESS GO AHEAD", "NAME",
158 "STATUS", "TIMING MARK", "RCTE", "NAOL", "NAOP",
159 "NAOCRD", "NAOHTS", "NAOHTD", "NAOFFD", "NAOVTS",
160 "NAOVTD", "NAOLFD", "EXTEND ASCII", "LOGOUT", "BYTE MACRO",
161 "DATA ENTRY TERMINAL", "SUPDUP", "SUPDUP OUTPUT",
162 "SEND LOCATION", "TERMINAL TYPE", "END OF RECORD",
163 "TACACS UID", "OUTPUT MARKING", "TTYLOC",
164 "3270 REGIME", "X.3 PAD", "NAWS", "TSPEED", "LFLOW",
165 "LINEMODE", "XDISPLOC", "OLD-ENVIRON", "AUTHENTICATION",
166 "ENCRYPT", "NEW-ENVIRON",
167 0,
168 };
169 #define TELOPT_FIRST TELOPT_BINARY
170 #define TELOPT_LAST TELOPT_NEW_ENVIRON
171 #define TELOPT_OK(x) ((unsigned int)(x) <= TELOPT_LAST)
172 #define TELOPT(x) telopts[(x)-TELOPT_FIRST]
173 #endif
174
175 /* sub-option qualifiers */
176 #define TELQUAL_IS 0 /* option is... */
177 #define TELQUAL_SEND 1 /* send option */
178 #define TELQUAL_INFO 2 /* ENVIRON: informational version of IS */
179 #define TELQUAL_REPLY 2 /* AUTHENTICATION: client version of IS */
180 #define TELQUAL_NAME 3 /* AUTHENTICATION: client version of IS */
181
182 #define LFLOW_OFF 0 /* Disable remote flow control */
183 #define LFLOW_ON 1 /* Enable remote flow control */
184 #define LFLOW_RESTART_ANY 2 /* Restart output on any char */
185 #define LFLOW_RESTART_XON 3 /* Restart output only on XON */
186
187 /*
188 * LINEMODE suboptions
189 */
190
191 #define LM_MODE 1
192 #define LM_FORWARDMASK 2
193 #define LM_SLC 3
194
195 #define MODE_EDIT 0x01
196 #define MODE_TRAPSIG 0x02
197 #define MODE_ACK 0x04
198 #define MODE_SOFT_TAB 0x08
199 #define MODE_LIT_ECHO 0x10
200
201 #define MODE_MASK 0x1f
202
203 #define SLC_SYNCH 1
204 #define SLC_BRK 2
205 #define SLC_IP 3
206 #define SLC_AO 4
207 #define SLC_AYT 5
208 #define SLC_EOR 6
209 #define SLC_ABORT 7
210 #define SLC_EOF 8
211 #define SLC_SUSP 9
212 #define SLC_EC 10
213 #define SLC_EL 11
214 #define SLC_EW 12
215 #define SLC_RP 13
216 #define SLC_LNEXT 14
217 #define SLC_XON 15
218 #define SLC_XOFF 16
219 #define SLC_FORW1 17
220 #define SLC_FORW2 18
221 #define SLC_MCL 19
222 #define SLC_MCR 20
223 #define SLC_MCWL 21
224 #define SLC_MCWR 22
225 #define SLC_MCBOL 23
226 #define SLC_MCEOL 24
227 #define SLC_INSRT 25
228 #define SLC_OVER 26
229 #define SLC_ECR 27
230 #define SLC_EWR 28
231 #define SLC_EBOL 29
232 #define SLC_EEOL 30
233
234 #define NSLC 30
235
236 /*
237 * For backwards compatibility, we define SLC_NAMES to be the
238 * list of names if SLC_NAMES is not defined.
239 */
240 #define SLC_NAMELIST "0", "SYNCH", "BRK", "IP", "AO", "AYT", "EOR", \
241 "ABORT", "EOF", "SUSP", "EC", "EL", "EW", "RP", \
242 "LNEXT", "XON", "XOFF", "FORW1", "FORW2", \
243 "MCL", "MCR", "MCWL", "MCWR", "MCBOL", \
244 "MCEOL", "INSRT", "OVER", "ECR", "EWR", \
245 "EBOL", "EEOL", \
246 0,
247
248 #ifdef SLC_NAMES
249 const char *slc_names[] = {
250 SLC_NAMELIST
251 };
252 #else
253 extern char *slc_names[];
254 #define SLC_NAMES SLC_NAMELIST
255 #endif
256
257 #define SLC_NAME_OK(x) ((unsigned int)(x) <= NSLC)
258 #define SLC_NAME(x) slc_names[x]
259
260 #define SLC_NOSUPPORT 0
261 #define SLC_CANTCHANGE 1
262 #define SLC_VARIABLE 2
263 #define SLC_DEFAULT 3
264 #define SLC_LEVELBITS 0x03
265
266 #define SLC_FUNC 0
267 #define SLC_FLAGS 1
268 #define SLC_VALUE 2
269
270 #define SLC_ACK 0x80
271 #define SLC_FLUSHIN 0x40
272 #define SLC_FLUSHOUT 0x20
273
274 #define OLD_ENV_VAR 1
275 #define OLD_ENV_VALUE 0
276 #define NEW_ENV_VAR 0
277 #define NEW_ENV_VALUE 1
278 #define ENV_ESC 2
279 #define ENV_USERVAR 3
280
281 /*
282 * AUTHENTICATION suboptions
283 */
284
285 /*
286 * Who is authenticating who ...
287 */
288 #define AUTH_WHO_CLIENT 0 /* Client authenticating server */
289 #define AUTH_WHO_SERVER 1 /* Server authenticating client */
290 #define AUTH_WHO_MASK 1
291
292 #define AUTHTYPE_NULL 0
293 #define AUTHTYPE_KERBEROS_V4 1
294 #define AUTHTYPE_KERBEROS_V5 2
295 #define AUTHTYPE_SPX 3
296 #define AUTHTYPE_MINK 4
297 #define AUTHTYPE_CNT 5
298
299 #define AUTHTYPE_TEST 99
300
301 #ifdef AUTH_NAMES
302 const char *authtype_names[] = {
303 "NULL", "KERBEROS_V4", "KERBEROS_V5", "SPX", "MINK", 0,
304 };
305 #else
306 extern char *authtype_names[];
307 #endif
308
309 #define AUTHTYPE_NAME_OK(x) ((unsigned int)(x) < AUTHTYPE_CNT)
310 #define AUTHTYPE_NAME(x) authtype_names[x]
311
312 /*
313 * ENCRYPTion suboptions
314 */
315 #define ENCRYPT_IS 0 /* I pick encryption type ... */
316 #define ENCRYPT_SUPPORT 1 /* I support encryption types ... */
317 #define ENCRYPT_REPLY 2 /* Initial setup response */
318 #define ENCRYPT_START 3 /* Am starting to send encrypted */
319 #define ENCRYPT_END 4 /* Am ending encrypted */
320 #define ENCRYPT_REQSTART 5 /* Request you start encrypting */
321 #define ENCRYPT_REQEND 6 /* Request you send encrypting */
322 #define ENCRYPT_ENC_KEYID 7
323 #define ENCRYPT_DEC_KEYID 8
324 #define ENCRYPT_CNT 9
325
326 #define ENCTYPE_ANY 0
327 #define ENCTYPE_DES_CFB64 1
328 #define ENCTYPE_DES_OFB64 2
329 #define ENCTYPE_CNT 3
330
331 #ifdef ENCRYPT_NAMES
332 const char *encrypt_names[] = {
333 "IS", "SUPPORT", "REPLY", "START", "END",
334 "REQUEST-START", "REQUEST-END", "ENC-KEYID", "DEC-KEYID",
335 0,
336 };
337 const char *enctype_names[] = {
338 "ANY", "DES_CFB64", "DES_OFB64", 0,
339 };
340 #else
341 extern char *encrypt_names[];
342 extern char *enctype_names[];
343 #endif
344
345 #define ENCRYPT_NAME_OK(x) ((unsigned int)(x) < ENCRYPT_CNT)
346 #define ENCRYPT_NAME(x) encrypt_names[x]
347
348 #define ENCTYPE_NAME_OK(x) ((unsigned int)(x) < ENCTYPE_CNT)
349 #define ENCTYPE_NAME(x) enctype_names[x]
350
351 /* normal */
352 static const char *cmds[] = {
353 "IS", "SEND", "INFO",
354 };
355
356 /* 37: Authentication */
357 static const char *authcmd[] = {
358 "IS", "SEND", "REPLY", "NAME",
359 };
360 static const char *authtype[] = {
361 "NULL", "KERBEROS_V4", "KERBEROS_V5", "SPX", "MINK",
362 "SRP", "RSA", "SSL", NULL, NULL,
363 "LOKI", "SSA", "KEA_SJ", "KEA_SJ_INTEG", "DSS",
364 "NTLM",
365 };
366
367 /* 38: Encryption */
368 static const char *enccmd[] = {
369 "IS", "SUPPORT", "REPLY", "START", "END",
370 "REQUEST-START", "REQUEST-END", "END_KEYID", "DEC_KEYID",
371 };
372 static const char *enctype[] = {
373 "NULL", "DES_CFB64", "DES_OFB64", "DES3_CFB64", "DES3_OFB64",
374 NULL, "CAST5_40_CFB64", "CAST5_40_OFB64", "CAST128_CFB64", "CAST128_OFB64",
375 };
376
377 #define STR_OR_ID(x, tab) \
378 (((x) < sizeof(tab)/sizeof(tab[0]) && tab[(x)]) ? tab[(x)] : numstr(x))
379
380 static char *
381 numstr(int x)
382 {
383 static char buf[20];
384
385 snprintf(buf, sizeof(buf), "%#x", x);
386 return buf;
387 }
388
389 /* sp points to IAC byte */
390 static int
391 telnet_parse(netdissect_options *ndo, const u_char *sp, u_int length, int print)
392 {
393 int i, x;
394 u_int c;
395 const u_char *osp, *p;
396 #define FETCH(c, sp, length) \
397 do { \
398 if (length < 1) \
399 goto pktend; \
400 ND_TCHECK_1(sp); \
401 c = EXTRACT_U_1(sp); \
402 sp++; \
403 length--; \
404 } while (0)
405
406 osp = sp;
407
408 FETCH(c, sp, length);
409 if (c != IAC)
410 goto pktend;
411 FETCH(c, sp, length);
412 if (c == IAC) { /* <IAC><IAC>! */
413 if (print)
414 ND_PRINT("IAC IAC");
415 goto done;
416 }
417
418 i = c - TELCMD_FIRST;
419 if (i < 0 || i > IAC - TELCMD_FIRST)
420 goto pktend;
421
422 switch (c) {
423 case DONT:
424 case DO:
425 case WONT:
426 case WILL:
427 case SB:
428 /* DONT/DO/WONT/WILL x */
429 FETCH(x, sp, length);
430 if (x >= 0 && x < NTELOPTS) {
431 if (print)
432 ND_PRINT("%s %s", telcmds[i], telopts[x]);
433 } else {
434 if (print)
435 ND_PRINT("%s %#x", telcmds[i], x);
436 }
437 if (c != SB)
438 break;
439 /* IAC SB .... IAC SE */
440 p = sp;
441 while (length > (u_int)(p + 1 - sp)) {
442 ND_TCHECK_2(p);
443 if (EXTRACT_U_1(p) == IAC && EXTRACT_U_1(p + 1) == SE)
444 break;
445 p++;
446 }
447 ND_TCHECK_1(p);
448 if (EXTRACT_U_1(p) != IAC)
449 goto pktend;
450
451 switch (x) {
452 case TELOPT_AUTHENTICATION:
453 if (p <= sp)
454 break;
455 FETCH(c, sp, length);
456 if (print)
457 ND_PRINT(" %s", STR_OR_ID(c, authcmd));
458 if (p <= sp)
459 break;
460 FETCH(c, sp, length);
461 if (print)
462 ND_PRINT(" %s", STR_OR_ID(c, authtype));
463 break;
464 case TELOPT_ENCRYPT:
465 if (p <= sp)
466 break;
467 FETCH(c, sp, length);
468 if (print)
469 ND_PRINT(" %s", STR_OR_ID(c, enccmd));
470 if (p <= sp)
471 break;
472 FETCH(c, sp, length);
473 if (print)
474 ND_PRINT(" %s", STR_OR_ID(c, enctype));
475 break;
476 default:
477 if (p <= sp)
478 break;
479 FETCH(c, sp, length);
480 if (print)
481 ND_PRINT(" %s", STR_OR_ID(c, cmds));
482 break;
483 }
484 while (p > sp) {
485 FETCH(x, sp, length);
486 if (print)
487 ND_PRINT(" %#x", x);
488 }
489 /* terminating IAC SE */
490 if (print)
491 ND_PRINT(" SE");
492 sp += 2;
493 break;
494 default:
495 if (print)
496 ND_PRINT("%s", telcmds[i]);
497 goto done;
498 }
499
500 done:
501 return sp - osp;
502
503 trunc:
504 ND_PRINT("%s", tstr);
505 pktend:
506 return -1;
507 #undef FETCH
508 }
509
510 void
511 telnet_print(netdissect_options *ndo, const u_char *sp, u_int length)
512 {
513 int first = 1;
514 const u_char *osp;
515 int l;
516
517 osp = sp;
518
519 ND_TCHECK_1(sp);
520 while (length > 0 && EXTRACT_U_1(sp) == IAC) {
521 /*
522 * Parse the Telnet command without printing it,
523 * to determine its length.
524 */
525 l = telnet_parse(ndo, sp, length, 0);
526 if (l < 0)
527 break;
528
529 /*
530 * now print it
531 */
532 if (ndo->ndo_Xflag && 2 < ndo->ndo_vflag) {
533 if (first)
534 ND_PRINT("\nTelnet:");
535 hex_print_with_offset(ndo, "\n", sp, l, sp - osp);
536 if (l > 8)
537 ND_PRINT("\n\t\t\t\t");
538 else
539 ND_PRINT("%*s\t", (8 - l) * 3, "");
540 } else
541 ND_PRINT("%s", (first) ? " [telnet " : ", ");
542
543 (void)telnet_parse(ndo, sp, length, 1);
544 first = 0;
545
546 sp += l;
547 length -= l;
548 ND_TCHECK_1(sp);
549 }
550 if (!first) {
551 if (ndo->ndo_Xflag && 2 < ndo->ndo_vflag)
552 ND_PRINT("\n");
553 else
554 ND_PRINT("]");
555 }
556 return;
557 trunc:
558 ND_PRINT("%s", tstr);
559 }
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