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[tcpdump] / print-ntp.c
1 /*
2 * Copyright (c) 1990, 1991, 1992, 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 * By Jeffrey Mogul/DECWRL
22 * loosely based on print-bootp.c
23 */
24
25 /* \summary: Network Time Protocol (NTP) printer */
26
27 /*
28 * specification:
29 *
30 * RFC 1119 - NTPv2
31 * RFC 1305 - NTPv3
32 * RFC 5905 - NTPv4
33 */
34
35 #ifdef HAVE_CONFIG_H
36 #include <config.h>
37 #endif
38
39 #include "netdissect-stdinc.h"
40
41 #include <time.h>
42
43 #include "netdissect.h"
44 #include "addrtoname.h"
45 #include "extract.h"
46
47 #include "ntp.h"
48
49 /*
50 * Based on ntp.h from the U of MD implementation
51 * This file is based on Version 2 of the NTP spec (RFC1119).
52 */
53
54 /* rfc2030
55 * 1 2 3
56 * 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
57 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
58 * |LI | VN |Mode | Stratum | Poll | Precision |
59 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
60 * | Root Delay |
61 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
62 * | Root Dispersion |
63 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
64 * | Reference Identifier |
65 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
66 * | |
67 * | Reference Timestamp (64) |
68 * | |
69 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
70 * | |
71 * | Originate Timestamp (64) |
72 * | |
73 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
74 * | |
75 * | Receive Timestamp (64) |
76 * | |
77 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
78 * | |
79 * | Transmit Timestamp (64) |
80 * | |
81 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
82 * | Key Identifier (optional) (32) |
83 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
84 * | |
85 * | |
86 * | Message Digest (optional) (128) |
87 * | |
88 * | |
89 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
90 */
91
92 /* Length of the NTP data message with the mandatory fields ("the header")
93 * and without any optional fields (extension, Key Identifier,
94 * Message Digest).
95 */
96 #define NTP_TIMEMSG_MINLEN 48U
97
98 struct ntp_time_data {
99 nd_uint8_t status; /* status of local clock and leap info */
100 nd_uint8_t stratum; /* Stratum level */
101 nd_int8_t ppoll; /* poll value */
102 nd_int8_t precision;
103 struct s_fixedpt root_delay;
104 struct s_fixedpt root_dispersion;
105 nd_uint32_t refid;
106 struct l_fixedpt ref_timestamp;
107 struct l_fixedpt org_timestamp;
108 struct l_fixedpt rec_timestamp;
109 struct l_fixedpt xmt_timestamp;
110 nd_uint32_t key_id;
111 nd_uint8_t message_digest[20];
112 };
113 /*
114 * Leap Second Codes (high order two bits)
115 */
116 #define NO_WARNING 0x00 /* no warning */
117 #define PLUS_SEC 0x40 /* add a second (61 seconds) */
118 #define MINUS_SEC 0x80 /* minus a second (59 seconds) */
119 #define ALARM 0xc0 /* alarm condition (clock unsynchronized) */
120
121 /*
122 * Clock Status Bits that Encode Version
123 */
124 #define NTPVERSION_1 0x08
125 #define VERSIONMASK 0x38
126 #define VERSIONSHIFT 3
127 #define LEAPMASK 0xc0
128 #define LEAPSHIFT 6
129 #ifdef MODEMASK
130 #undef MODEMASK /* Solaris sucks */
131 #endif
132 #define MODEMASK 0x07
133 #define MODESHIFT 0
134
135 /*
136 * Code values
137 */
138 #define MODE_UNSPEC 0 /* unspecified */
139 #define MODE_SYM_ACT 1 /* symmetric active */
140 #define MODE_SYM_PAS 2 /* symmetric passive */
141 #define MODE_CLIENT 3 /* client */
142 #define MODE_SERVER 4 /* server */
143 #define MODE_BROADCAST 5 /* broadcast */
144 #define MODE_CONTROL 6 /* control message */
145 #define MODE_RES2 7 /* reserved */
146
147 /*
148 * Stratum Definitions
149 */
150 #define UNSPECIFIED 0
151 #define PRIM_REF 1 /* radio clock */
152 #define INFO_QUERY 62 /* **** THIS implementation dependent **** */
153 #define INFO_REPLY 63 /* **** THIS implementation dependent **** */
154
155 static void p_sfix(netdissect_options *ndo, const struct s_fixedpt *);
156 static void p_ntp_delta(netdissect_options *, const struct l_fixedpt *, const struct l_fixedpt *);
157 static void p_poll(netdissect_options *, const int);
158
159 static const struct tok ntp_mode_values[] = {
160 { MODE_UNSPEC, "unspecified" },
161 { MODE_SYM_ACT, "symmetric active" },
162 { MODE_SYM_PAS, "symmetric passive" },
163 { MODE_CLIENT, "Client" },
164 { MODE_SERVER, "Server" },
165 { MODE_BROADCAST, "Broadcast" },
166 { MODE_CONTROL, "Control Message" },
167 { MODE_RES2, "Reserved" },
168 { 0, NULL }
169 };
170
171 static const struct tok ntp_leapind_values[] = {
172 { NO_WARNING, "" },
173 { PLUS_SEC, "+1s" },
174 { MINUS_SEC, "-1s" },
175 { ALARM, "clock unsynchronized" },
176 { 0, NULL }
177 };
178
179 static const struct tok ntp_stratum_values[] = {
180 { UNSPECIFIED, "unspecified" },
181 { PRIM_REF, "primary reference" },
182 { 0, NULL }
183 };
184
185 /* draft-ietf-ntp-mode-6-cmds-02
186 * 0 1 2 3
187 * 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
188 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
189 * |LI | VN |Mode |R|E|M| OpCode | Sequence Number |
190 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
191 * | Status | Association ID |
192 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
193 * | Offset | Count |
194 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
195 * | |
196 * / Data (up to 468 bytes) /
197 * | |
198 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
199 * | Padding (optional) |
200 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
201 * | |
202 * / Authenticator (optional, 96 bytes) /
203 * | |
204 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
205 *
206 * Figure 1: NTP Control Message Header
207 */
208
209 /* Length of the NTP control message with the mandatory fields ("the header")
210 * and without any optional fields (Data, Padding, Authenticator).
211 */
212 #define NTP_CTRLMSG_MINLEN 12U
213
214 struct ntp_control_data {
215 nd_uint8_t magic; /* LI, VN, Mode */
216 nd_uint8_t control; /* R, E, M, OpCode */
217 nd_uint16_t sequence; /* Sequence Number */
218 nd_uint16_t status; /* Status */
219 nd_uint16_t assoc; /* Association ID */
220 nd_uint16_t offset; /* Offset */
221 nd_uint16_t count; /* Count */
222 nd_uint8_t data[564]; /* Data, [Padding, [Authenticator]] */
223 };
224
225 /*
226 * Print NTP time requests and responses
227 */
228 static void
229 ntp_time_print(netdissect_options *ndo,
230 const struct ntp_time_data *bp, u_int length)
231 {
232 uint8_t stratum;
233
234 if (length < NTP_TIMEMSG_MINLEN)
235 goto invalid;
236
237 stratum = GET_U_1(bp->stratum);
238 ND_PRINT(", Stratum %u (%s)",
239 stratum,
240 tok2str(ntp_stratum_values, (stratum >=2 && stratum<=15) ? "secondary reference" : "reserved", stratum));
241
242 ND_PRINT(", poll %d", GET_S_1(bp->ppoll));
243 p_poll(ndo, GET_S_1(bp->ppoll));
244
245 ND_PRINT(", precision %d", GET_S_1(bp->precision));
246
247 ND_TCHECK_SIZE(&bp->root_delay);
248 ND_PRINT("\n\tRoot Delay: ");
249 p_sfix(ndo, &bp->root_delay);
250
251 ND_TCHECK_SIZE(&bp->root_dispersion);
252 ND_PRINT(", Root dispersion: ");
253 p_sfix(ndo, &bp->root_dispersion);
254
255 ND_TCHECK_4(bp->refid);
256 ND_PRINT(", Reference-ID: ");
257 /* Interpretation depends on stratum */
258 switch (stratum) {
259
260 case UNSPECIFIED:
261 ND_PRINT("(unspec)");
262 break;
263
264 case PRIM_REF:
265 if (nd_printn(ndo, (const u_char *)&(bp->refid), 4, ndo->ndo_snapend))
266 goto trunc;
267 break;
268
269 case INFO_QUERY:
270 ND_PRINT("%s INFO_QUERY", GET_IPADDR_STRING(bp->refid));
271 /* this doesn't have more content */
272 return;
273
274 case INFO_REPLY:
275 ND_PRINT("%s INFO_REPLY", GET_IPADDR_STRING(bp->refid));
276 /* this is too complex to be worth printing */
277 return;
278
279 default:
280 /* In NTPv4 (RFC 5905) refid is an IPv4 address or first 32 bits of
281 MD5 sum of IPv6 address */
282 ND_PRINT("0x%08x", GET_BE_U_4(bp->refid));
283 break;
284 }
285
286 ND_TCHECK_SIZE(&bp->ref_timestamp);
287 ND_PRINT("\n\t Reference Timestamp: ");
288 p_ntp_time(ndo, &(bp->ref_timestamp));
289
290 ND_TCHECK_SIZE(&bp->org_timestamp);
291 ND_PRINT("\n\t Originator Timestamp: ");
292 p_ntp_time(ndo, &(bp->org_timestamp));
293
294 ND_TCHECK_SIZE(&bp->rec_timestamp);
295 ND_PRINT("\n\t Receive Timestamp: ");
296 p_ntp_time(ndo, &(bp->rec_timestamp));
297
298 ND_TCHECK_SIZE(&bp->xmt_timestamp);
299 ND_PRINT("\n\t Transmit Timestamp: ");
300 p_ntp_time(ndo, &(bp->xmt_timestamp));
301
302 ND_PRINT("\n\t Originator - Receive Timestamp: ");
303 p_ntp_delta(ndo, &(bp->org_timestamp), &(bp->rec_timestamp));
304
305 ND_PRINT("\n\t Originator - Transmit Timestamp: ");
306 p_ntp_delta(ndo, &(bp->org_timestamp), &(bp->xmt_timestamp));
307
308 /* FIXME: this code is not aware of any extension fields */
309 if (length == NTP_TIMEMSG_MINLEN + 4) { /* Optional: key-id (crypto-NAK) */
310 ND_PRINT("\n\tKey id: %u", GET_BE_U_4(bp->key_id));
311 } else if (length == NTP_TIMEMSG_MINLEN + 4 + 16) { /* Optional: key-id + 128-bit digest */
312 ND_PRINT("\n\tKey id: %u", GET_BE_U_4(bp->key_id));
313 ND_TCHECK_LEN(bp->message_digest, 16);
314 ND_PRINT("\n\tAuthentication: %08x%08x%08x%08x",
315 GET_BE_U_4(bp->message_digest),
316 GET_BE_U_4(bp->message_digest + 4),
317 GET_BE_U_4(bp->message_digest + 8),
318 GET_BE_U_4(bp->message_digest + 12));
319 } else if (length == NTP_TIMEMSG_MINLEN + 4 + 20) { /* Optional: key-id + 160-bit digest */
320 ND_PRINT("\n\tKey id: %u", GET_BE_U_4(bp->key_id));
321 ND_TCHECK_LEN(bp->message_digest, 20);
322 ND_PRINT("\n\tAuthentication: %08x%08x%08x%08x%08x",
323 GET_BE_U_4(bp->message_digest),
324 GET_BE_U_4(bp->message_digest + 4),
325 GET_BE_U_4(bp->message_digest + 8),
326 GET_BE_U_4(bp->message_digest + 12),
327 GET_BE_U_4(bp->message_digest + 16));
328 } else if (length > NTP_TIMEMSG_MINLEN) {
329 ND_PRINT("\n\t(%u more bytes after the header)", length - NTP_TIMEMSG_MINLEN);
330 }
331 return;
332
333 invalid:
334 nd_print_invalid(ndo);
335 ND_TCHECK_LEN(bp, length);
336 return;
337
338 trunc:
339 nd_print_trunc(ndo);
340 }
341
342 /*
343 * Print NTP control message requests and responses
344 */
345 static void
346 ntp_control_print(netdissect_options *ndo,
347 const struct ntp_control_data *cd, u_int length)
348 {
349 uint8_t control, R, E, M, opcode;
350 uint16_t sequence, status, assoc, offset, count;
351
352 if (length < NTP_CTRLMSG_MINLEN)
353 goto invalid;
354
355 control = GET_U_1(cd->control);
356 R = (control & 0x80) != 0;
357 E = (control & 0x40) != 0;
358 M = (control & 0x20) != 0;
359 opcode = control & 0x1f;
360 ND_PRINT(", %s, %s, %s, OpCode=%u\n",
361 R ? "Response" : "Request", E ? "Error" : "OK",
362 M ? "More" : "Last", opcode);
363
364 sequence = GET_BE_U_2(cd->sequence);
365 ND_PRINT("\tSequence=%hu", sequence);
366
367 status = GET_BE_U_2(cd->status);
368 ND_PRINT(", Status=%#hx", status);
369
370 assoc = GET_BE_U_2(cd->assoc);
371 ND_PRINT(", Assoc.=%hu", assoc);
372
373 offset = GET_BE_U_2(cd->offset);
374 ND_PRINT(", Offset=%hu", offset);
375
376 count = GET_BE_U_2(cd->count);
377 ND_PRINT(", Count=%hu", count);
378
379 if (NTP_CTRLMSG_MINLEN + count > length)
380 goto invalid;
381 if (count != 0) {
382 ND_TCHECK_LEN(cd->data, count);
383 ND_PRINT("\n\tTO-BE-DONE: data not interpreted");
384 }
385 return;
386
387 invalid:
388 nd_print_invalid(ndo);
389 ND_TCHECK_LEN(cd, length);
390 return;
391
392 trunc:
393 nd_print_trunc(ndo);
394 }
395
396 union ntpdata {
397 struct ntp_time_data td;
398 struct ntp_control_data cd;
399 };
400
401 /*
402 * Print NTP requests, handling the common VN, LI, and Mode
403 */
404 void
405 ntp_print(netdissect_options *ndo,
406 const u_char *cp, u_int length)
407 {
408 const union ntpdata *bp = (const union ntpdata *)cp;
409 u_int mode, version, leapind;
410 uint8_t status;
411
412 ndo->ndo_protocol = "ntp";
413 status = GET_U_1(bp->td.status);
414
415 version = (status & VERSIONMASK) >> VERSIONSHIFT;
416 ND_PRINT("NTPv%u", version);
417
418 mode = (status & MODEMASK) >> MODESHIFT;
419 if (!ndo->ndo_vflag) {
420 ND_PRINT(", %s, length %u",
421 tok2str(ntp_mode_values, "Unknown mode", mode),
422 length);
423 return;
424 }
425
426 ND_PRINT(", %s, length %u\n",
427 tok2str(ntp_mode_values, "Unknown mode", mode), length);
428
429 /* leapind = (status & LEAPMASK) >> LEAPSHIFT; */
430 leapind = (status & LEAPMASK);
431 ND_PRINT("\tLeap indicator: %s (%u)",
432 tok2str(ntp_leapind_values, "Unknown", leapind),
433 leapind);
434
435 switch (mode) {
436
437 case MODE_UNSPEC:
438 case MODE_SYM_ACT:
439 case MODE_SYM_PAS:
440 case MODE_CLIENT:
441 case MODE_SERVER:
442 case MODE_BROADCAST:
443 ntp_time_print(ndo, &bp->td, length);
444 break;
445
446 case MODE_CONTROL:
447 ntp_control_print(ndo, &bp->cd, length);
448 break;
449
450 default:
451 break; /* XXX: not implemented! */
452 }
453 }
454
455 static void
456 p_sfix(netdissect_options *ndo,
457 const struct s_fixedpt *sfp)
458 {
459 int i;
460 int f;
461 double ff;
462
463 i = GET_BE_U_2(sfp->int_part);
464 f = GET_BE_U_2(sfp->fraction);
465 ff = f / 65536.0; /* shift radix point by 16 bits */
466 f = (int)(ff * 1000000.0); /* Treat fraction as parts per million */
467 ND_PRINT("%d.%06d", i, f);
468 }
469
470 /* Prints time difference between *lfp and *olfp */
471 static void
472 p_ntp_delta(netdissect_options *ndo,
473 const struct l_fixedpt *olfp,
474 const struct l_fixedpt *lfp)
475 {
476 uint32_t u, uf;
477 uint32_t ou, ouf;
478 uint32_t i;
479 uint32_t f;
480 double ff;
481 int signbit;
482
483 u = GET_BE_U_4(lfp->int_part);
484 ou = GET_BE_U_4(olfp->int_part);
485 uf = GET_BE_U_4(lfp->fraction);
486 ouf = GET_BE_U_4(olfp->fraction);
487 if (ou == 0 && ouf == 0) {
488 p_ntp_time(ndo, lfp);
489 return;
490 }
491
492 if (u > ou) { /* new is definitely greater than old */
493 signbit = 0;
494 i = u - ou;
495 f = uf - ouf;
496 if (ouf > uf) /* must borrow from high-order bits */
497 i -= 1;
498 } else if (u < ou) { /* new is definitely less than old */
499 signbit = 1;
500 i = ou - u;
501 f = ouf - uf;
502 if (uf > ouf) /* must borrow from the high-order bits */
503 i -= 1;
504 } else { /* int_part is zero */
505 i = 0;
506 if (uf > ouf) {
507 signbit = 0;
508 f = uf - ouf;
509 } else {
510 signbit = 1;
511 f = ouf - uf;
512 }
513 }
514
515 ff = f;
516 if (ff < 0.0) /* some compilers are buggy */
517 ff += FMAXINT;
518 ff = ff / FMAXINT; /* shift radix point by 32 bits */
519 f = (uint32_t)(ff * 1000000000.0); /* treat fraction as parts per billion */
520 ND_PRINT("%s%u.%09u", signbit ? "-" : "+", i, f);
521 }
522
523 /* Prints polling interval in log2 as seconds or fraction of second */
524 static void
525 p_poll(netdissect_options *ndo,
526 const int poll_interval)
527 {
528 if (poll_interval <= -32 || poll_interval >= 32)
529 return;
530
531 if (poll_interval >= 0)
532 ND_PRINT(" (%us)", 1U << poll_interval);
533 else
534 ND_PRINT(" (1/%us)", 1U << -poll_interval);
535 }
536
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