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remove redundant ND_TCHECK, let GET_ routines handle checks
[tcpdump] / print-l2tp.c
1 /*
2 * Copyright (c) 1991, 1993, 1994, 1995, 1996, 1997
3 * The Regents of the University of California. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that: (1) source code distributions
7 * retain the above copyright notice and this paragraph in its entirety, (2)
8 * distributions including binary code include the above copyright notice and
9 * this paragraph in its entirety in the documentation or other materials
10 * provided with the distribution, and (3) all advertising materials mentioning
11 * features or use of this software display the following acknowledgement:
12 * ``This product includes software developed by the University of California,
13 * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
14 * the University nor the names of its contributors may be used to endorse
15 * or promote products derived from this software without specific prior
16 * written permission.
17 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
18 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
19 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
20 *
21 * L2TP support contributed by Motonori Shindo (mshindo@mshindo.net)
22 */
23
24 /* \summary: Layer Two Tunneling Protocol (L2TP) printer */
25
26 /* specification: RFC 2661 */
27
28 #ifdef HAVE_CONFIG_H
29 #include <config.h>
30 #endif
31
32 #include "netdissect-stdinc.h"
33
34 #include "netdissect.h"
35 #include "extract.h"
36
37 #define L2TP_FLAG_TYPE 0x8000 /* Type (0=Data, 1=Control) */
38 #define L2TP_FLAG_LENGTH 0x4000 /* Length */
39 #define L2TP_FLAG_SEQUENCE 0x0800 /* Sequence */
40 #define L2TP_FLAG_OFFSET 0x0200 /* Offset */
41 #define L2TP_FLAG_PRIORITY 0x0100 /* Priority */
42
43 #define L2TP_VERSION_MASK 0x000f /* Version Mask */
44 #define L2TP_VERSION_L2F 0x0001 /* L2F */
45 #define L2TP_VERSION_L2TP 0x0002 /* L2TP */
46
47 #define L2TP_AVP_HDR_FLAG_MANDATORY 0x8000 /* Mandatory Flag */
48 #define L2TP_AVP_HDR_FLAG_HIDDEN 0x4000 /* Hidden Flag */
49 #define L2TP_AVP_HDR_LEN_MASK 0x03ff /* Length Mask */
50
51 #define L2TP_FRAMING_CAP_SYNC_MASK 0x00000001 /* Synchronous */
52 #define L2TP_FRAMING_CAP_ASYNC_MASK 0x00000002 /* Asynchronous */
53
54 #define L2TP_FRAMING_TYPE_SYNC_MASK 0x00000001 /* Synchronous */
55 #define L2TP_FRAMING_TYPE_ASYNC_MASK 0x00000002 /* Asynchronous */
56
57 #define L2TP_BEARER_CAP_DIGITAL_MASK 0x00000001 /* Digital */
58 #define L2TP_BEARER_CAP_ANALOG_MASK 0x00000002 /* Analog */
59
60 #define L2TP_BEARER_TYPE_DIGITAL_MASK 0x00000001 /* Digital */
61 #define L2TP_BEARER_TYPE_ANALOG_MASK 0x00000002 /* Analog */
62
63 /* Authen Type */
64 #define L2TP_AUTHEN_TYPE_RESERVED 0x0000 /* Reserved */
65 #define L2TP_AUTHEN_TYPE_TEXTUAL 0x0001 /* Textual username/password exchange */
66 #define L2TP_AUTHEN_TYPE_CHAP 0x0002 /* PPP CHAP */
67 #define L2TP_AUTHEN_TYPE_PAP 0x0003 /* PPP PAP */
68 #define L2TP_AUTHEN_TYPE_NO_AUTH 0x0004 /* No Authentication */
69 #define L2TP_AUTHEN_TYPE_MSCHAPv1 0x0005 /* MSCHAPv1 */
70
71 #define L2TP_PROXY_AUTH_ID_MASK 0x00ff
72
73
74 #define L2TP_MSGTYPE_SCCRQ 1 /* Start-Control-Connection-Request */
75 #define L2TP_MSGTYPE_SCCRP 2 /* Start-Control-Connection-Reply */
76 #define L2TP_MSGTYPE_SCCCN 3 /* Start-Control-Connection-Connected */
77 #define L2TP_MSGTYPE_STOPCCN 4 /* Stop-Control-Connection-Notification */
78 #define L2TP_MSGTYPE_HELLO 6 /* Hello */
79 #define L2TP_MSGTYPE_OCRQ 7 /* Outgoing-Call-Request */
80 #define L2TP_MSGTYPE_OCRP 8 /* Outgoing-Call-Reply */
81 #define L2TP_MSGTYPE_OCCN 9 /* Outgoing-Call-Connected */
82 #define L2TP_MSGTYPE_ICRQ 10 /* Incoming-Call-Request */
83 #define L2TP_MSGTYPE_ICRP 11 /* Incoming-Call-Reply */
84 #define L2TP_MSGTYPE_ICCN 12 /* Incoming-Call-Connected */
85 #define L2TP_MSGTYPE_CDN 14 /* Call-Disconnect-Notify */
86 #define L2TP_MSGTYPE_WEN 15 /* WAN-Error-Notify */
87 #define L2TP_MSGTYPE_SLI 16 /* Set-Link-Info */
88
89 static const struct tok l2tp_msgtype2str[] = {
90 { L2TP_MSGTYPE_SCCRQ, "SCCRQ" },
91 { L2TP_MSGTYPE_SCCRP, "SCCRP" },
92 { L2TP_MSGTYPE_SCCCN, "SCCCN" },
93 { L2TP_MSGTYPE_STOPCCN, "StopCCN" },
94 { L2TP_MSGTYPE_HELLO, "HELLO" },
95 { L2TP_MSGTYPE_OCRQ, "OCRQ" },
96 { L2TP_MSGTYPE_OCRP, "OCRP" },
97 { L2TP_MSGTYPE_OCCN, "OCCN" },
98 { L2TP_MSGTYPE_ICRQ, "ICRQ" },
99 { L2TP_MSGTYPE_ICRP, "ICRP" },
100 { L2TP_MSGTYPE_ICCN, "ICCN" },
101 { L2TP_MSGTYPE_CDN, "CDN" },
102 { L2TP_MSGTYPE_WEN, "WEN" },
103 { L2TP_MSGTYPE_SLI, "SLI" },
104 { 0, NULL }
105 };
106
107 #define L2TP_AVP_MSGTYPE 0 /* Message Type */
108 #define L2TP_AVP_RESULT_CODE 1 /* Result Code */
109 #define L2TP_AVP_PROTO_VER 2 /* Protocol Version */
110 #define L2TP_AVP_FRAMING_CAP 3 /* Framing Capabilities */
111 #define L2TP_AVP_BEARER_CAP 4 /* Bearer Capabilities */
112 #define L2TP_AVP_TIE_BREAKER 5 /* Tie Breaker */
113 #define L2TP_AVP_FIRM_VER 6 /* Firmware Revision */
114 #define L2TP_AVP_HOST_NAME 7 /* Host Name */
115 #define L2TP_AVP_VENDOR_NAME 8 /* Vendor Name */
116 #define L2TP_AVP_ASSND_TUN_ID 9 /* Assigned Tunnel ID */
117 #define L2TP_AVP_RECV_WIN_SIZE 10 /* Receive Window Size */
118 #define L2TP_AVP_CHALLENGE 11 /* Challenge */
119 #define L2TP_AVP_Q931_CC 12 /* Q.931 Cause Code */
120 #define L2TP_AVP_CHALLENGE_RESP 13 /* Challenge Response */
121 #define L2TP_AVP_ASSND_SESS_ID 14 /* Assigned Session ID */
122 #define L2TP_AVP_CALL_SER_NUM 15 /* Call Serial Number */
123 #define L2TP_AVP_MINIMUM_BPS 16 /* Minimum BPS */
124 #define L2TP_AVP_MAXIMUM_BPS 17 /* Maximum BPS */
125 #define L2TP_AVP_BEARER_TYPE 18 /* Bearer Type */
126 #define L2TP_AVP_FRAMING_TYPE 19 /* Framing Type */
127 #define L2TP_AVP_PACKET_PROC_DELAY 20 /* Packet Processing Delay (OBSOLETE) */
128 #define L2TP_AVP_CALLED_NUMBER 21 /* Called Number */
129 #define L2TP_AVP_CALLING_NUMBER 22 /* Calling Number */
130 #define L2TP_AVP_SUB_ADDRESS 23 /* Sub-Address */
131 #define L2TP_AVP_TX_CONN_SPEED 24 /* (Tx) Connect Speed */
132 #define L2TP_AVP_PHY_CHANNEL_ID 25 /* Physical Channel ID */
133 #define L2TP_AVP_INI_RECV_LCP 26 /* Initial Received LCP CONFREQ */
134 #define L2TP_AVP_LAST_SENT_LCP 27 /* Last Sent LCP CONFREQ */
135 #define L2TP_AVP_LAST_RECV_LCP 28 /* Last Received LCP CONFREQ */
136 #define L2TP_AVP_PROXY_AUTH_TYPE 29 /* Proxy Authen Type */
137 #define L2TP_AVP_PROXY_AUTH_NAME 30 /* Proxy Authen Name */
138 #define L2TP_AVP_PROXY_AUTH_CHAL 31 /* Proxy Authen Challenge */
139 #define L2TP_AVP_PROXY_AUTH_ID 32 /* Proxy Authen ID */
140 #define L2TP_AVP_PROXY_AUTH_RESP 33 /* Proxy Authen Response */
141 #define L2TP_AVP_CALL_ERRORS 34 /* Call Errors */
142 #define L2TP_AVP_ACCM 35 /* ACCM */
143 #define L2TP_AVP_RANDOM_VECTOR 36 /* Random Vector */
144 #define L2TP_AVP_PRIVATE_GRP_ID 37 /* Private Group ID */
145 #define L2TP_AVP_RX_CONN_SPEED 38 /* (Rx) Connect Speed */
146 #define L2TP_AVP_SEQ_REQUIRED 39 /* Sequencing Required */
147 #define L2TP_AVP_PPP_DISCON_CC 46 /* PPP Disconnect Cause Code - RFC 3145 */
148
149 static const struct tok l2tp_avp2str[] = {
150 { L2TP_AVP_MSGTYPE, "MSGTYPE" },
151 { L2TP_AVP_RESULT_CODE, "RESULT_CODE" },
152 { L2TP_AVP_PROTO_VER, "PROTO_VER" },
153 { L2TP_AVP_FRAMING_CAP, "FRAMING_CAP" },
154 { L2TP_AVP_BEARER_CAP, "BEARER_CAP" },
155 { L2TP_AVP_TIE_BREAKER, "TIE_BREAKER" },
156 { L2TP_AVP_FIRM_VER, "FIRM_VER" },
157 { L2TP_AVP_HOST_NAME, "HOST_NAME" },
158 { L2TP_AVP_VENDOR_NAME, "VENDOR_NAME" },
159 { L2TP_AVP_ASSND_TUN_ID, "ASSND_TUN_ID" },
160 { L2TP_AVP_RECV_WIN_SIZE, "RECV_WIN_SIZE" },
161 { L2TP_AVP_CHALLENGE, "CHALLENGE" },
162 { L2TP_AVP_Q931_CC, "Q931_CC", },
163 { L2TP_AVP_CHALLENGE_RESP, "CHALLENGE_RESP" },
164 { L2TP_AVP_ASSND_SESS_ID, "ASSND_SESS_ID" },
165 { L2TP_AVP_CALL_SER_NUM, "CALL_SER_NUM" },
166 { L2TP_AVP_MINIMUM_BPS, "MINIMUM_BPS" },
167 { L2TP_AVP_MAXIMUM_BPS, "MAXIMUM_BPS" },
168 { L2TP_AVP_BEARER_TYPE, "BEARER_TYPE" },
169 { L2TP_AVP_FRAMING_TYPE, "FRAMING_TYPE" },
170 { L2TP_AVP_PACKET_PROC_DELAY, "PACKET_PROC_DELAY" },
171 { L2TP_AVP_CALLED_NUMBER, "CALLED_NUMBER" },
172 { L2TP_AVP_CALLING_NUMBER, "CALLING_NUMBER" },
173 { L2TP_AVP_SUB_ADDRESS, "SUB_ADDRESS" },
174 { L2TP_AVP_TX_CONN_SPEED, "TX_CONN_SPEED" },
175 { L2TP_AVP_PHY_CHANNEL_ID, "PHY_CHANNEL_ID" },
176 { L2TP_AVP_INI_RECV_LCP, "INI_RECV_LCP" },
177 { L2TP_AVP_LAST_SENT_LCP, "LAST_SENT_LCP" },
178 { L2TP_AVP_LAST_RECV_LCP, "LAST_RECV_LCP" },
179 { L2TP_AVP_PROXY_AUTH_TYPE, "PROXY_AUTH_TYPE" },
180 { L2TP_AVP_PROXY_AUTH_NAME, "PROXY_AUTH_NAME" },
181 { L2TP_AVP_PROXY_AUTH_CHAL, "PROXY_AUTH_CHAL" },
182 { L2TP_AVP_PROXY_AUTH_ID, "PROXY_AUTH_ID" },
183 { L2TP_AVP_PROXY_AUTH_RESP, "PROXY_AUTH_RESP" },
184 { L2TP_AVP_CALL_ERRORS, "CALL_ERRORS" },
185 { L2TP_AVP_ACCM, "ACCM" },
186 { L2TP_AVP_RANDOM_VECTOR, "RANDOM_VECTOR" },
187 { L2TP_AVP_PRIVATE_GRP_ID, "PRIVATE_GRP_ID" },
188 { L2TP_AVP_RX_CONN_SPEED, "RX_CONN_SPEED" },
189 { L2TP_AVP_SEQ_REQUIRED, "SEQ_REQUIRED" },
190 { L2TP_AVP_PPP_DISCON_CC, "PPP_DISCON_CC" },
191 { 0, NULL }
192 };
193
194 static const struct tok l2tp_authentype2str[] = {
195 { L2TP_AUTHEN_TYPE_RESERVED, "Reserved" },
196 { L2TP_AUTHEN_TYPE_TEXTUAL, "Textual" },
197 { L2TP_AUTHEN_TYPE_CHAP, "CHAP" },
198 { L2TP_AUTHEN_TYPE_PAP, "PAP" },
199 { L2TP_AUTHEN_TYPE_NO_AUTH, "No Auth" },
200 { L2TP_AUTHEN_TYPE_MSCHAPv1, "MS-CHAPv1" },
201 { 0, NULL }
202 };
203
204 #define L2TP_PPP_DISCON_CC_DIRECTION_GLOBAL 0
205 #define L2TP_PPP_DISCON_CC_DIRECTION_AT_PEER 1
206 #define L2TP_PPP_DISCON_CC_DIRECTION_AT_LOCAL 2
207
208 static const struct tok l2tp_cc_direction2str[] = {
209 { L2TP_PPP_DISCON_CC_DIRECTION_GLOBAL, "global error" },
210 { L2TP_PPP_DISCON_CC_DIRECTION_AT_PEER, "at peer" },
211 { L2TP_PPP_DISCON_CC_DIRECTION_AT_LOCAL,"at local" },
212 { 0, NULL }
213 };
214
215 #if 0
216 static char *l2tp_result_code_StopCCN[] = {
217 "Reserved",
218 "General request to clear control connection",
219 "General error--Error Code indicates the problem",
220 "Control channel already exists",
221 "Requester is not authorized to establish a control channel",
222 "The protocol version of the requester is not supported",
223 "Requester is being shut down",
224 "Finite State Machine error"
225 #define L2TP_MAX_RESULT_CODE_STOPCC_INDEX 8
226 };
227 #endif
228
229 #if 0
230 static char *l2tp_result_code_CDN[] = {
231 "Reserved",
232 "Call disconnected due to loss of carrier",
233 "Call disconnected for the reason indicated in error code",
234 "Call disconnected for administrative reasons",
235 "Call failed due to lack of appropriate facilities being "
236 "available (temporary condition)",
237 "Call failed due to lack of appropriate facilities being "
238 "available (permanent condition)",
239 "Invalid destination",
240 "Call failed due to no carrier detected",
241 "Call failed due to detection of a busy signal",
242 "Call failed due to lack of a dial tone",
243 "Call was not established within time allotted by LAC",
244 "Call was connected but no appropriate framing was detected"
245 #define L2TP_MAX_RESULT_CODE_CDN_INDEX 12
246 };
247 #endif
248
249 #if 0
250 static char *l2tp_error_code_general[] = {
251 "No general error",
252 "No control connection exists yet for this LAC-LNS pair",
253 "Length is wrong",
254 "One of the field values was out of range or "
255 "reserved field was non-zero"
256 "Insufficient resources to handle this operation now",
257 "The Session ID is invalid in this context",
258 "A generic vendor-specific error occurred in the LAC",
259 "Try another"
260 #define L2TP_MAX_ERROR_CODE_GENERAL_INDEX 8
261 };
262 #endif
263
264 /******************************/
265 /* generic print out routines */
266 /******************************/
267 static void
268 print_string(netdissect_options *ndo, const u_char *dat, u_int length)
269 {
270 u_int i;
271 for (i=0; i<length; i++) {
272 fn_print_char(ndo, GET_U_1(dat));
273 dat++;
274 }
275 }
276
277 static void
278 print_octets(netdissect_options *ndo, const u_char *dat, u_int length)
279 {
280 u_int i;
281 for (i=0; i<length; i++) {
282 ND_PRINT("%02x", GET_U_1(dat));
283 dat++;
284 }
285 }
286
287 static void
288 print_16bits_val(netdissect_options *ndo, const uint8_t *dat)
289 {
290 ND_PRINT("%u", GET_BE_U_2(dat));
291 }
292
293 static void
294 print_32bits_val(netdissect_options *ndo, const uint8_t *dat)
295 {
296 ND_PRINT("%u", GET_BE_U_4(dat));
297 }
298
299 /***********************************/
300 /* AVP-specific print out routines */
301 /***********************************/
302 static void
303 l2tp_msgtype_print(netdissect_options *ndo, const u_char *dat, u_int length)
304 {
305 if (length < 2) {
306 ND_PRINT("AVP too short");
307 return;
308 }
309 ND_PRINT("%s", tok2str(l2tp_msgtype2str, "MSGTYPE-#%u",
310 GET_BE_U_2(dat)));
311 }
312
313 static void
314 l2tp_result_code_print(netdissect_options *ndo, const u_char *dat, u_int length)
315 {
316 /* Result Code */
317 if (length < 2) {
318 ND_PRINT("AVP too short");
319 return;
320 }
321 ND_PRINT("%u", GET_BE_U_2(dat));
322 dat += 2;
323 length -= 2;
324
325 /* Error Code (opt) */
326 if (length == 0)
327 return;
328 if (length < 2) {
329 ND_PRINT(" AVP too short");
330 return;
331 }
332 ND_PRINT("/%u", GET_BE_U_2(dat));
333 dat += 2;
334 length -= 2;
335
336 /* Error Message (opt) */
337 if (length == 0)
338 return;
339 ND_PRINT(" ");
340 print_string(ndo, dat, length);
341 }
342
343 static void
344 l2tp_proto_ver_print(netdissect_options *ndo, const u_char *dat, u_int length)
345 {
346 if (length < 2) {
347 ND_PRINT("AVP too short");
348 return;
349 }
350 ND_PRINT("%u.%u", (GET_BE_U_2(dat) >> 8),
351 (GET_BE_U_2(dat) & 0xff));
352 }
353
354 static void
355 l2tp_framing_cap_print(netdissect_options *ndo, const u_char *dat, u_int length)
356 {
357 if (length < 4) {
358 ND_PRINT("AVP too short");
359 return;
360 }
361 if (GET_BE_U_4(dat) & L2TP_FRAMING_CAP_ASYNC_MASK) {
362 ND_PRINT("A");
363 }
364 if (GET_BE_U_4(dat) & L2TP_FRAMING_CAP_SYNC_MASK) {
365 ND_PRINT("S");
366 }
367 }
368
369 static void
370 l2tp_bearer_cap_print(netdissect_options *ndo, const u_char *dat, u_int length)
371 {
372 if (length < 4) {
373 ND_PRINT("AVP too short");
374 return;
375 }
376 if (GET_BE_U_4(dat) & L2TP_BEARER_CAP_ANALOG_MASK) {
377 ND_PRINT("A");
378 }
379 if (GET_BE_U_4(dat) & L2TP_BEARER_CAP_DIGITAL_MASK) {
380 ND_PRINT("D");
381 }
382 }
383
384 static void
385 l2tp_q931_cc_print(netdissect_options *ndo, const u_char *dat, u_int length)
386 {
387 if (length < 3) {
388 ND_PRINT("AVP too short");
389 return;
390 }
391 print_16bits_val(ndo, dat);
392 ND_PRINT(", %02x", GET_U_1(dat + 2));
393 dat += 3;
394 length -= 3;
395 if (length != 0) {
396 ND_PRINT(" ");
397 print_string(ndo, dat, length);
398 }
399 }
400
401 static void
402 l2tp_bearer_type_print(netdissect_options *ndo, const u_char *dat, u_int length)
403 {
404 if (length < 4) {
405 ND_PRINT("AVP too short");
406 return;
407 }
408 if (GET_BE_U_4(dat) & L2TP_BEARER_TYPE_ANALOG_MASK) {
409 ND_PRINT("A");
410 }
411 if (GET_BE_U_4(dat) & L2TP_BEARER_TYPE_DIGITAL_MASK) {
412 ND_PRINT("D");
413 }
414 }
415
416 static void
417 l2tp_framing_type_print(netdissect_options *ndo, const u_char *dat, u_int length)
418 {
419 if (length < 4) {
420 ND_PRINT("AVP too short");
421 return;
422 }
423 if (GET_BE_U_4(dat) & L2TP_FRAMING_TYPE_ASYNC_MASK) {
424 ND_PRINT("A");
425 }
426 if (GET_BE_U_4(dat) & L2TP_FRAMING_TYPE_SYNC_MASK) {
427 ND_PRINT("S");
428 }
429 }
430
431 static void
432 l2tp_packet_proc_delay_print(netdissect_options *ndo)
433 {
434 ND_PRINT("obsolete");
435 }
436
437 static void
438 l2tp_proxy_auth_type_print(netdissect_options *ndo, const u_char *dat, u_int length)
439 {
440 if (length < 2) {
441 ND_PRINT("AVP too short");
442 return;
443 }
444 ND_PRINT("%s", tok2str(l2tp_authentype2str,
445 "AuthType-#%u", GET_BE_U_2(dat)));
446 }
447
448 static void
449 l2tp_proxy_auth_id_print(netdissect_options *ndo, const u_char *dat, u_int length)
450 {
451 if (length < 2) {
452 ND_PRINT("AVP too short");
453 return;
454 }
455 ND_PRINT("%u", GET_BE_U_2(dat) & L2TP_PROXY_AUTH_ID_MASK);
456 }
457
458 static void
459 l2tp_call_errors_print(netdissect_options *ndo, const u_char *dat, u_int length)
460 {
461 uint32_t val;
462
463 if (length < 2) {
464 ND_PRINT("AVP too short");
465 return;
466 }
467 dat += 2; /* skip "Reserved" */
468 length -= 2;
469
470 if (length < 4) {
471 ND_PRINT("AVP too short");
472 return;
473 }
474 val = GET_BE_U_4(dat); dat += 4; length -= 4;
475 ND_PRINT("CRCErr=%u ", val);
476
477 if (length < 4) {
478 ND_PRINT("AVP too short");
479 return;
480 }
481 val = GET_BE_U_4(dat); dat += 4; length -= 4;
482 ND_PRINT("FrameErr=%u ", val);
483
484 if (length < 4) {
485 ND_PRINT("AVP too short");
486 return;
487 }
488 val = GET_BE_U_4(dat); dat += 4; length -= 4;
489 ND_PRINT("HardOver=%u ", val);
490
491 if (length < 4) {
492 ND_PRINT("AVP too short");
493 return;
494 }
495 val = GET_BE_U_4(dat); dat += 4; length -= 4;
496 ND_PRINT("BufOver=%u ", val);
497
498 if (length < 4) {
499 ND_PRINT("AVP too short");
500 return;
501 }
502 val = GET_BE_U_4(dat); dat += 4; length -= 4;
503 ND_PRINT("Timeout=%u ", val);
504
505 if (length < 4) {
506 ND_PRINT("AVP too short");
507 return;
508 }
509 val = GET_BE_U_4(dat); dat += 4; length -= 4;
510 ND_PRINT("AlignErr=%u ", val);
511 }
512
513 static void
514 l2tp_accm_print(netdissect_options *ndo, const u_char *dat, u_int length)
515 {
516 uint32_t val;
517
518 if (length < 2) {
519 ND_PRINT("AVP too short");
520 return;
521 }
522 dat += 2; /* skip "Reserved" */
523 length -= 2;
524
525 if (length < 4) {
526 ND_PRINT("AVP too short");
527 return;
528 }
529 val = GET_BE_U_4(dat); dat += 4; length -= 4;
530 ND_PRINT("send=%08x ", val);
531
532 if (length < 4) {
533 ND_PRINT("AVP too short");
534 return;
535 }
536 val = GET_BE_U_4(dat); dat += 4; length -= 4;
537 ND_PRINT("recv=%08x ", val);
538 }
539
540 static void
541 l2tp_ppp_discon_cc_print(netdissect_options *ndo, const u_char *dat, u_int length)
542 {
543 if (length < 5) {
544 ND_PRINT("AVP too short");
545 return;
546 }
547 /* Disconnect Code */
548 ND_PRINT("%04x, ", GET_BE_U_2(dat));
549 dat += 2;
550 length -= 2;
551 /* Control Protocol Number */
552 ND_PRINT("%04x ", GET_BE_U_2(dat));
553 dat += 2;
554 length -= 2;
555 /* Direction */
556 ND_PRINT("%s", tok2str(l2tp_cc_direction2str,
557 "Direction-#%u", GET_U_1(dat)));
558 dat++;
559 length--;
560
561 if (length != 0) {
562 ND_PRINT(" ");
563 print_string(ndo, (const u_char *)dat, length);
564 }
565 }
566
567 static u_int
568 l2tp_avp_print(netdissect_options *ndo, const u_char *dat, u_int length)
569 {
570 u_int len;
571 uint16_t attr_type;
572 int hidden = FALSE;
573
574 ND_PRINT(" ");
575 /* Flags & Length */
576 len = GET_BE_U_2(dat) & L2TP_AVP_HDR_LEN_MASK;
577
578 /* If it is not long enough to contain the header, we'll give up. */
579 if (len < 6)
580 goto trunc;
581
582 /* If it goes past the end of the remaining length of the packet,
583 we'll give up. */
584 if (len > (u_int)length)
585 goto trunc;
586
587 /* If it goes past the end of the remaining length of the captured
588 data, we'll give up. */
589 ND_TCHECK_LEN(dat, len);
590
591 /*
592 * After this point, we don't need to check whether we go past
593 * the length of the captured data; however, we *do* need to
594 * check whether we go past the end of the AVP.
595 */
596
597 if (GET_BE_U_2(dat) & L2TP_AVP_HDR_FLAG_MANDATORY) {
598 ND_PRINT("*");
599 }
600 if (GET_BE_U_2(dat) & L2TP_AVP_HDR_FLAG_HIDDEN) {
601 hidden = TRUE;
602 ND_PRINT("?");
603 }
604 dat += 2;
605
606 if (GET_BE_U_2(dat)) {
607 /* Vendor Specific Attribute */
608 ND_PRINT("VENDOR%04x:", GET_BE_U_2(dat)); dat += 2;
609 ND_PRINT("ATTR%04x", GET_BE_U_2(dat)); dat += 2;
610 ND_PRINT("(");
611 print_octets(ndo, dat, len-6);
612 ND_PRINT(")");
613 } else {
614 /* IETF-defined Attributes */
615 dat += 2;
616 attr_type = GET_BE_U_2(dat); dat += 2;
617 ND_PRINT("%s", tok2str(l2tp_avp2str, "AVP-#%u", attr_type));
618 ND_PRINT("(");
619 if (hidden) {
620 ND_PRINT("???");
621 } else {
622 switch (attr_type) {
623 case L2TP_AVP_MSGTYPE:
624 l2tp_msgtype_print(ndo, dat, len-6);
625 break;
626 case L2TP_AVP_RESULT_CODE:
627 l2tp_result_code_print(ndo, dat, len-6);
628 break;
629 case L2TP_AVP_PROTO_VER:
630 l2tp_proto_ver_print(ndo, dat, len-6);
631 break;
632 case L2TP_AVP_FRAMING_CAP:
633 l2tp_framing_cap_print(ndo, dat, len-6);
634 break;
635 case L2TP_AVP_BEARER_CAP:
636 l2tp_bearer_cap_print(ndo, dat, len-6);
637 break;
638 case L2TP_AVP_TIE_BREAKER:
639 if (len-6 < 8) {
640 ND_PRINT("AVP too short");
641 break;
642 }
643 print_octets(ndo, dat, 8);
644 break;
645 case L2TP_AVP_FIRM_VER:
646 case L2TP_AVP_ASSND_TUN_ID:
647 case L2TP_AVP_RECV_WIN_SIZE:
648 case L2TP_AVP_ASSND_SESS_ID:
649 if (len-6 < 2) {
650 ND_PRINT("AVP too short");
651 break;
652 }
653 print_16bits_val(ndo, dat);
654 break;
655 case L2TP_AVP_HOST_NAME:
656 case L2TP_AVP_VENDOR_NAME:
657 case L2TP_AVP_CALLING_NUMBER:
658 case L2TP_AVP_CALLED_NUMBER:
659 case L2TP_AVP_SUB_ADDRESS:
660 case L2TP_AVP_PROXY_AUTH_NAME:
661 case L2TP_AVP_PRIVATE_GRP_ID:
662 print_string(ndo, dat, len-6);
663 break;
664 case L2TP_AVP_CHALLENGE:
665 case L2TP_AVP_INI_RECV_LCP:
666 case L2TP_AVP_LAST_SENT_LCP:
667 case L2TP_AVP_LAST_RECV_LCP:
668 case L2TP_AVP_PROXY_AUTH_CHAL:
669 case L2TP_AVP_PROXY_AUTH_RESP:
670 case L2TP_AVP_RANDOM_VECTOR:
671 print_octets(ndo, dat, len-6);
672 break;
673 case L2TP_AVP_Q931_CC:
674 l2tp_q931_cc_print(ndo, dat, len-6);
675 break;
676 case L2TP_AVP_CHALLENGE_RESP:
677 if (len-6 < 16) {
678 ND_PRINT("AVP too short");
679 break;
680 }
681 print_octets(ndo, dat, 16);
682 break;
683 case L2TP_AVP_CALL_SER_NUM:
684 case L2TP_AVP_MINIMUM_BPS:
685 case L2TP_AVP_MAXIMUM_BPS:
686 case L2TP_AVP_TX_CONN_SPEED:
687 case L2TP_AVP_PHY_CHANNEL_ID:
688 case L2TP_AVP_RX_CONN_SPEED:
689 if (len-6 < 4) {
690 ND_PRINT("AVP too short");
691 break;
692 }
693 print_32bits_val(ndo, dat);
694 break;
695 case L2TP_AVP_BEARER_TYPE:
696 l2tp_bearer_type_print(ndo, dat, len-6);
697 break;
698 case L2TP_AVP_FRAMING_TYPE:
699 l2tp_framing_type_print(ndo, dat, len-6);
700 break;
701 case L2TP_AVP_PACKET_PROC_DELAY:
702 l2tp_packet_proc_delay_print(ndo);
703 break;
704 case L2TP_AVP_PROXY_AUTH_TYPE:
705 l2tp_proxy_auth_type_print(ndo, dat, len-6);
706 break;
707 case L2TP_AVP_PROXY_AUTH_ID:
708 l2tp_proxy_auth_id_print(ndo, dat, len-6);
709 break;
710 case L2TP_AVP_CALL_ERRORS:
711 l2tp_call_errors_print(ndo, dat, len-6);
712 break;
713 case L2TP_AVP_ACCM:
714 l2tp_accm_print(ndo, dat, len-6);
715 break;
716 case L2TP_AVP_SEQ_REQUIRED:
717 break; /* No Attribute Value */
718 case L2TP_AVP_PPP_DISCON_CC:
719 l2tp_ppp_discon_cc_print(ndo, dat, len-6);
720 break;
721 default:
722 break;
723 }
724 }
725 ND_PRINT(")");
726 }
727
728 return (len);
729
730 trunc:
731 nd_print_trunc(ndo);
732 return (0);
733 }
734
735
736 void
737 l2tp_print(netdissect_options *ndo, const u_char *dat, u_int length)
738 {
739 const u_char *ptr = dat;
740 u_int cnt = 0; /* total octets consumed */
741 uint16_t pad;
742 int flag_t, flag_l, flag_s, flag_o;
743 uint16_t l2tp_len;
744
745 ndo->ndo_protocol = "l2tp";
746 flag_t = flag_l = flag_s = flag_o = FALSE;
747
748 if ((GET_BE_U_2(ptr) & L2TP_VERSION_MASK) == L2TP_VERSION_L2TP) {
749 ND_PRINT(" l2tp:");
750 } else if ((GET_BE_U_2(ptr) & L2TP_VERSION_MASK) == L2TP_VERSION_L2F) {
751 ND_PRINT(" l2f:");
752 return; /* nothing to do */
753 } else {
754 ND_PRINT(" Unknown Version, neither L2F(1) nor L2TP(2)");
755 return; /* nothing we can do */
756 }
757
758 ND_PRINT("[");
759 if (GET_BE_U_2(ptr) & L2TP_FLAG_TYPE) {
760 flag_t = TRUE;
761 ND_PRINT("T");
762 }
763 if (GET_BE_U_2(ptr) & L2TP_FLAG_LENGTH) {
764 flag_l = TRUE;
765 ND_PRINT("L");
766 }
767 if (GET_BE_U_2(ptr) & L2TP_FLAG_SEQUENCE) {
768 flag_s = TRUE;
769 ND_PRINT("S");
770 }
771 if (GET_BE_U_2(ptr) & L2TP_FLAG_OFFSET) {
772 flag_o = TRUE;
773 ND_PRINT("O");
774 }
775 if (GET_BE_U_2(ptr) & L2TP_FLAG_PRIORITY)
776 ND_PRINT("P");
777 ND_PRINT("]");
778
779 ptr += 2;
780 cnt += 2;
781
782 if (flag_l) {
783 l2tp_len = GET_BE_U_2(ptr);
784 ptr += 2;
785 cnt += 2;
786 } else {
787 l2tp_len = 0;
788 }
789 /* Tunnel ID */
790 ND_PRINT("(%u/", GET_BE_U_2(ptr));
791 ptr += 2;
792 cnt += 2;
793 /* Session ID */
794 ND_PRINT("%u)", GET_BE_U_2(ptr));
795 ptr += 2;
796 cnt += 2;
797
798 if (flag_s) {
799 ND_PRINT("Ns=%u,", GET_BE_U_2(ptr));
800 ptr += 2;
801 cnt += 2;
802 ND_PRINT("Nr=%u", GET_BE_U_2(ptr));
803 ptr += 2;
804 cnt += 2;
805 }
806
807 if (flag_o) { /* Offset Size */
808 pad = GET_BE_U_2(ptr);
809 ptr += (2 + pad);
810 cnt += (2 + pad);
811 }
812
813 if (flag_l) {
814 if (length < l2tp_len) {
815 ND_PRINT(" Length %u larger than packet", l2tp_len);
816 return;
817 }
818 length = l2tp_len;
819 }
820 if (length < cnt) {
821 ND_PRINT(" Length %u smaller than header length", length);
822 return;
823 }
824 if (flag_t) {
825 if (!flag_l) {
826 ND_PRINT(" No length");
827 return;
828 }
829 if (length - cnt == 0) {
830 ND_PRINT(" ZLB");
831 } else {
832 /*
833 * Print AVPs.
834 */
835 while (length - cnt != 0) {
836 u_int avp_length;
837
838 avp_length = l2tp_avp_print(ndo, ptr, length - cnt);
839 if (avp_length == 0) {
840 /*
841 * Truncated.
842 */
843 break;
844 }
845 cnt += avp_length;
846 ptr += avp_length;
847 }
848 }
849 } else {
850 ND_PRINT(" {");
851 ppp_print(ndo, ptr, length - cnt);
852 ND_PRINT("}");
853 }
854 }
[mirror] the TCPdump network dissector