]> The Tcpdump Group git mirrors - tcpdump/blob - print-bfd.c
projects / tcpdump / blob
summary | shortlog | log | commit | commitdiff | tree
history | raw | HEAD
PIM: Fix some length checks
[tcpdump] / print-bfd.c
1 /*
2 * Redistribution and use in source and binary forms, with or without
3 * modification, are permitted provided that: (1) source code
4 * distributions retain the above copyright notice and this paragraph
5 * in its entirety, and (2) distributions including binary code include
6 * the above copyright notice and this paragraph in its entirety in
7 * the documentation or other materials provided with the distribution.
8 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND
9 * WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT
10 * LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
11 * FOR A PARTICULAR PURPOSE.
12 *
13 * Original code by Hannes Gredler (hannes@gredler.at)
14 */
15
16 /* \summary: Bidirectional Forwarding Detection (BFD) printer */
17
18 /*
19 * specification: draft-ietf-bfd-base-01 for version 0,
20 * RFC 5880 for version 1, and RFC 5881
21 */
22
23 #ifdef HAVE_CONFIG_H
24 #include <config.h>
25 #endif
26
27 #include "netdissect-stdinc.h"
28
29 #include "netdissect.h"
30 #include "extract.h"
31
32 #include "udp.h"
33
34 /*
35 * Control packet, BFDv0, draft-ietf-bfd-base-01
36 *
37 * 0 1 2 3
38 * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
39 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
40 * |Vers | Diag |H|D|P|F|C|A|Rsv| Detect Mult | Length |
41 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
42 * | My Discriminator |
43 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
44 * | Your Discriminator |
45 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
46 * | Desired Min TX Interval |
47 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
48 * | Required Min RX Interval |
49 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
50 * | Required Min Echo RX Interval |
51 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
52 */
53
54 /*
55 * Control packet, BFDv1, RFC 5880
56 *
57 * 0 1 2 3
58 * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
59 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
60 * |Vers | Diag |Sta|P|F|C|A|D|M| Detect Mult | Length |
61 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
62 * | My Discriminator |
63 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
64 * | Your Discriminator |
65 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
66 * | Desired Min TX Interval |
67 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
68 * | Required Min RX Interval |
69 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
70 * | Required Min Echo RX Interval |
71 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
72 */
73
74 struct bfd_header_t {
75 nd_uint8_t version_diag;
76 nd_uint8_t flags;
77 nd_uint8_t detect_time_multiplier;
78 nd_uint8_t length;
79 nd_uint32_t my_discriminator;
80 nd_uint32_t your_discriminator;
81 nd_uint32_t desired_min_tx_interval;
82 nd_uint32_t required_min_rx_interval;
83 nd_uint32_t required_min_echo_interval;
84 };
85
86 /*
87 * An optional Authentication Header may be present
88 *
89 * 0 1 2 3
90 * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
91 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
92 * | Auth Type | Auth Len | Authentication Data... |
93 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
94 */
95
96 struct bfd_auth_header_t {
97 nd_uint8_t auth_type;
98 nd_uint8_t auth_len;
99 nd_uint8_t auth_data;
100 nd_uint8_t dummy; /* minimum 4 bytes */
101 };
102
103 enum auth_type {
104 AUTH_PASSWORD = 1,
105 AUTH_MD5 = 2,
106 AUTH_MET_MD5 = 3,
107 AUTH_SHA1 = 4,
108 AUTH_MET_SHA1 = 5
109 };
110
111 static const struct tok bfd_v1_authentication_values[] = {
112 { AUTH_PASSWORD, "Simple Password" },
113 { AUTH_MD5, "Keyed MD5" },
114 { AUTH_MET_MD5, "Meticulous Keyed MD5" },
115 { AUTH_SHA1, "Keyed SHA1" },
116 { AUTH_MET_SHA1, "Meticulous Keyed SHA1" },
117 { 0, NULL }
118 };
119
120 enum auth_length {
121 AUTH_PASSWORD_FIELD_MIN_LEN = 4, /* header + password min: 3 + 1 */
122 AUTH_PASSWORD_FIELD_MAX_LEN = 19, /* header + password max: 3 + 16 */
123 AUTH_MD5_FIELD_LEN = 24,
124 AUTH_MD5_HASH_LEN = 16,
125 AUTH_SHA1_FIELD_LEN = 28,
126 AUTH_SHA1_HASH_LEN = 20
127 };
128
129 #define BFD_EXTRACT_VERSION(x) (((x)&0xe0)>>5)
130 #define BFD_EXTRACT_DIAG(x) ((x)&0x1f)
131
132 static const struct tok bfd_diag_values[] = {
133 { 0, "No Diagnostic" },
134 { 1, "Control Detection Time Expired" },
135 { 2, "Echo Function Failed" },
136 { 3, "Neighbor Signaled Session Down" },
137 { 4, "Forwarding Plane Reset" },
138 { 5, "Path Down" },
139 { 6, "Concatenated Path Down" },
140 { 7, "Administratively Down" },
141 { 8, "Reverse Concatenated Path Down" },
142 { 0, NULL }
143 };
144
145 static const struct tok bfd_port_values[] = {
146 { BFD_CONTROL_PORT, "Control" },
147 { BFD_MULTIHOP_PORT, "Multihop" },
148 { BFD_LAG_PORT, "Lag" },
149 { 0, NULL }
150 };
151
152 #define BFD_FLAG_AUTH 0x04
153
154 static const struct tok bfd_v0_flag_values[] = {
155 { 0x80, "I Hear You" },
156 { 0x40, "Demand" },
157 { 0x20, "Poll" },
158 { 0x10, "Final" },
159 { 0x08, "Control Plane Independent" },
160 { BFD_FLAG_AUTH, "Authentication Present" },
161 { 0x02, "Reserved" },
162 { 0x01, "Reserved" },
163 { 0, NULL }
164 };
165
166 static const struct tok bfd_v1_flag_values[] = {
167 { 0x20, "Poll" },
168 { 0x10, "Final" },
169 { 0x08, "Control Plane Independent" },
170 { BFD_FLAG_AUTH, "Authentication Present" },
171 { 0x02, "Demand" },
172 { 0x01, "Multipoint" },
173 { 0, NULL }
174 };
175
176 static const struct tok bfd_v1_state_values[] = {
177 { 0, "AdminDown" },
178 { 1, "Down" },
179 { 2, "Init" },
180 { 3, "Up" },
181 { 0, NULL }
182 };
183
184 static int
185 auth_print(netdissect_options *ndo, const u_char *pptr)
186 {
187 const struct bfd_auth_header_t *bfd_auth_header;
188 uint8_t auth_type, auth_len;
189 int i;
190
191 pptr += sizeof (struct bfd_header_t);
192 bfd_auth_header = (const struct bfd_auth_header_t *)pptr;
193 ND_TCHECK_SIZE(bfd_auth_header);
194 auth_type = GET_U_1(bfd_auth_header->auth_type);
195 auth_len = GET_U_1(bfd_auth_header->auth_len);
196 ND_PRINT("\n\tAuthentication: %s (%u), length: %u",
197 tok2str(bfd_v1_authentication_values,"Unknown",auth_type),
198 auth_type, auth_len);
199 pptr += 2;
200 ND_PRINT("\n\t Auth Key ID: %u", GET_U_1(pptr));
201
202 switch(auth_type) {
203 case AUTH_PASSWORD:
204 /*
205 * Simple Password Authentication Section Format
206 *
207 * 0 1 2 3
208 * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
209 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
210 * | Auth Type | Auth Len | Auth Key ID | Password... |
211 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
212 * | ... |
213 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
214 */
215 if (auth_len < AUTH_PASSWORD_FIELD_MIN_LEN ||
216 auth_len > AUTH_PASSWORD_FIELD_MAX_LEN) {
217 ND_PRINT("[invalid length %u]",
218 auth_len);
219 break;
220 }
221 pptr++;
222 ND_PRINT(", Password: ");
223 /* the length is equal to the password length plus three */
224 if (nd_printn(ndo, pptr, auth_len - 3,
225 ndo->ndo_snapend))
226 goto trunc;
227 break;
228 case AUTH_MD5:
229 case AUTH_MET_MD5:
230 /*
231 * Keyed MD5 and Meticulous Keyed MD5 Authentication Section Format
232 *
233 * 0 1 2 3
234 * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
235 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
236 * | Auth Type | Auth Len | Auth Key ID | Reserved |
237 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
238 * | Sequence Number |
239 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
240 * | Auth Key/Digest... |
241 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
242 * | ... |
243 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
244 */
245 if (auth_len != AUTH_MD5_FIELD_LEN) {
246 ND_PRINT("[invalid length %u]",
247 auth_len);
248 break;
249 }
250 pptr += 2;
251 ND_TCHECK_4(pptr);
252 ND_PRINT(", Sequence Number: 0x%08x", GET_BE_U_4(pptr));
253 pptr += 4;
254 ND_TCHECK_LEN(pptr, AUTH_MD5_HASH_LEN);
255 ND_PRINT("\n\t Digest: ");
256 for(i = 0; i < AUTH_MD5_HASH_LEN; i++)
257 ND_PRINT("%02x", GET_U_1(pptr + i));
258 break;
259 case AUTH_SHA1:
260 case AUTH_MET_SHA1:
261 /*
262 * Keyed SHA1 and Meticulous Keyed SHA1 Authentication Section Format
263 *
264 * 0 1 2 3
265 * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
266 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
267 * | Auth Type | Auth Len | Auth Key ID | Reserved |
268 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
269 * | Sequence Number |
270 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
271 * | Auth Key/Hash... |
272 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
273 * | ... |
274 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
275 */
276 if (auth_len != AUTH_SHA1_FIELD_LEN) {
277 ND_PRINT("[invalid length %u]",
278 auth_len);
279 break;
280 }
281 pptr += 2;
282 ND_TCHECK_4(pptr);
283 ND_PRINT(", Sequence Number: 0x%08x", GET_BE_U_4(pptr));
284 pptr += 4;
285 ND_TCHECK_LEN(pptr, AUTH_SHA1_HASH_LEN);
286 ND_PRINT("\n\t Hash: ");
287 for(i = 0; i < AUTH_SHA1_HASH_LEN; i++)
288 ND_PRINT("%02x", GET_U_1(pptr + i));
289 break;
290 }
291 return 0;
292
293 trunc:
294 return 1;
295 }
296
297 void
298 bfd_print(netdissect_options *ndo, const u_char *pptr,
299 u_int len, u_int port)
300 {
301 ndo->ndo_protocol = "bfd";
302 if (port == BFD_CONTROL_PORT ||
303 port == BFD_MULTIHOP_PORT ||
304 port == BFD_LAG_PORT) {
305 /*
306 * Control packet.
307 */
308 const struct bfd_header_t *bfd_header;
309 uint8_t version_diag;
310 uint8_t version = 0;
311 uint8_t flags;
312
313 bfd_header = (const struct bfd_header_t *)pptr;
314 ND_TCHECK_SIZE(bfd_header);
315 version_diag = GET_U_1(bfd_header->version_diag);
316 version = BFD_EXTRACT_VERSION(version_diag);
317 flags = GET_U_1(bfd_header->flags);
318
319 switch (version) {
320
321 /* BFDv0 */
322 case 0:
323 if (ndo->ndo_vflag < 1)
324 {
325 ND_PRINT("BFDv0, Control, Flags: [%s], length: %u",
326 bittok2str(bfd_v0_flag_values, "none", flags),
327 len);
328 return;
329 }
330
331 ND_PRINT("BFDv0, length: %u\n\tControl, Flags: [%s], Diagnostic: %s (0x%02x)",
332 len,
333 bittok2str(bfd_v0_flag_values, "none", flags),
334 tok2str(bfd_diag_values,"unknown",BFD_EXTRACT_DIAG(version_diag)),
335 BFD_EXTRACT_DIAG(version_diag));
336
337 ND_PRINT("\n\tDetection Timer Multiplier: %u (%u ms Detection time), BFD Length: %u",
338 GET_U_1(bfd_header->detect_time_multiplier),
339 GET_U_1(bfd_header->detect_time_multiplier) * GET_BE_U_4(bfd_header->desired_min_tx_interval)/1000,
340 GET_U_1(bfd_header->length));
341
342
343 ND_PRINT("\n\tMy Discriminator: 0x%08x",
344 GET_BE_U_4(bfd_header->my_discriminator));
345 ND_PRINT(", Your Discriminator: 0x%08x",
346 GET_BE_U_4(bfd_header->your_discriminator));
347 ND_PRINT("\n\t Desired min Tx Interval: %4u ms",
348 GET_BE_U_4(bfd_header->desired_min_tx_interval)/1000);
349 ND_PRINT("\n\t Required min Rx Interval: %4u ms",
350 GET_BE_U_4(bfd_header->required_min_rx_interval)/1000);
351 ND_PRINT("\n\t Required min Echo Interval: %4u ms",
352 GET_BE_U_4(bfd_header->required_min_echo_interval)/1000);
353
354 if (flags & BFD_FLAG_AUTH) {
355 if (auth_print(ndo, pptr))
356 goto trunc;
357 }
358 break;
359
360 /* BFDv1 */
361 case 1:
362 if (ndo->ndo_vflag < 1)
363 {
364 ND_PRINT("BFDv1, %s, State %s, Flags: [%s], length: %u",
365 tok2str(bfd_port_values, "unknown (%u)", port),
366 tok2str(bfd_v1_state_values, "unknown (%u)", (flags & 0xc0) >> 6),
367 bittok2str(bfd_v1_flag_values, "none", flags & 0x3f),
368 len);
369 return;
370 }
371
372 ND_PRINT("BFDv1, length: %u\n\t%s, State %s, Flags: [%s], Diagnostic: %s (0x%02x)",
373 len,
374 tok2str(bfd_port_values, "unknown (%u)", port),
375 tok2str(bfd_v1_state_values, "unknown (%u)", (flags & 0xc0) >> 6),
376 bittok2str(bfd_v1_flag_values, "none", flags & 0x3f),
377 tok2str(bfd_diag_values,"unknown",BFD_EXTRACT_DIAG(version_diag)),
378 BFD_EXTRACT_DIAG(version_diag));
379
380 ND_PRINT("\n\tDetection Timer Multiplier: %u (%u ms Detection time), BFD Length: %u",
381 GET_U_1(bfd_header->detect_time_multiplier),
382 GET_U_1(bfd_header->detect_time_multiplier) * GET_BE_U_4(bfd_header->desired_min_tx_interval)/1000,
383 GET_U_1(bfd_header->length));
384
385
386 ND_PRINT("\n\tMy Discriminator: 0x%08x",
387 GET_BE_U_4(bfd_header->my_discriminator));
388 ND_PRINT(", Your Discriminator: 0x%08x",
389 GET_BE_U_4(bfd_header->your_discriminator));
390 ND_PRINT("\n\t Desired min Tx Interval: %4u ms",
391 GET_BE_U_4(bfd_header->desired_min_tx_interval)/1000);
392 ND_PRINT("\n\t Required min Rx Interval: %4u ms",
393 GET_BE_U_4(bfd_header->required_min_rx_interval)/1000);
394 ND_PRINT("\n\t Required min Echo Interval: %4u ms",
395 GET_BE_U_4(bfd_header->required_min_echo_interval)/1000);
396
397 if (flags & BFD_FLAG_AUTH) {
398 if (auth_print(ndo, pptr))
399 goto trunc;
400 }
401 break;
402
403 default:
404 ND_PRINT("BFDv%u, Control, length: %u",
405 version,
406 len);
407 if (ndo->ndo_vflag >= 1) {
408 if(!print_unknown_data(ndo, pptr,"\n\t",len))
409 return;
410 }
411 break;
412 }
413 } else if (port == BFD_ECHO_PORT) {
414 /*
415 * Echo packet.
416 */
417 ND_PRINT("BFD, Echo, length: %u",
418 len);
419 if (ndo->ndo_vflag >= 1) {
420 if(!print_unknown_data(ndo, pptr,"\n\t",len))
421 return;
422 }
423 } else {
424 /*
425 * Unknown packet type.
426 */
427 ND_PRINT("BFD, unknown (%u), length: %u",
428 port,
429 len);
430 if (ndo->ndo_vflag >= 1) {
431 if(!print_unknown_data(ndo, pptr,"\n\t",len))
432 return;
433 }
434 }
435 return;
436
437 trunc:
438 nd_print_trunc(ndo);
439 }
[mirror] the TCPdump network dissector