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 * Format and print ntp packets.
22 * By Jeffrey Mogul/DECWRL
23 * loosely based on print-bootp.c
24 */
25
26 #include <sys/cdefs.h>
27 #ifndef lint
28 __RCSID("$NetBSD: print-ntp.c,v 1.5 2014/11/20 03:05:03 christos Exp $");
29 #endif
30
31 #define NETDISSECT_REWORKED
32 #ifdef HAVE_CONFIG_H
33 #include "config.h"
34 #endif
35
36 #include <tcpdump-stdinc.h>
37
38 #ifdef HAVE_STRFTIME
39 #include <time.h>
40 #endif
41
42 #include "interface.h"
43 #include "addrtoname.h"
44 #include "extract.h"
45
46 /*
47 * Based on ntp.h from the U of MD implementation
48 * This file is based on Version 2 of the NTP spec (RFC1119).
49 */
50
51 /*
52 * Definitions for the masses
53 */
54 #define JAN_1970 2208988800U /* 1970 - 1900 in seconds */
55
56 /*
57 * Structure definitions for NTP fixed point values
58 *
59 * 0 1 2 3
60 * 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
61 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
62 * | Integer Part |
63 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
64 * | Fraction Part |
65 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
66 *
67 * 0 1 2 3
68 * 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
69 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
70 * | Integer Part | Fraction Part |
71 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
72 */
73 struct l_fixedpt {
74 uint32_t int_part;
75 uint32_t fraction;
76 };
77
78 struct s_fixedpt {
79 uint16_t int_part;
80 uint16_t fraction;
81 };
82
83 /* rfc2030
84 * 1 2 3
85 * 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
86 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
87 * |LI | VN |Mode | Stratum | Poll | Precision |
88 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
89 * | Root Delay |
90 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
91 * | Root Dispersion |
92 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
93 * | Reference Identifier |
94 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
95 * | |
96 * | Reference Timestamp (64) |
97 * | |
98 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
99 * | |
100 * | Originate Timestamp (64) |
101 * | |
102 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
103 * | |
104 * | Receive Timestamp (64) |
105 * | |
106 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
107 * | |
108 * | Transmit Timestamp (64) |
109 * | |
110 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
111 * | Key Identifier (optional) (32) |
112 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
113 * | |
114 * | |
115 * | Message Digest (optional) (128) |
116 * | |
117 * | |
118 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
119 */
120
121 struct ntpdata {
122 u_char status; /* status of local clock and leap info */
123 u_char stratum; /* Stratum level */
124 u_char ppoll; /* poll value */
125 int precision:8;
126 struct s_fixedpt root_delay;
127 struct s_fixedpt root_dispersion;
128 uint32_t refid;
129 struct l_fixedpt ref_timestamp;
130 struct l_fixedpt org_timestamp;
131 struct l_fixedpt rec_timestamp;
132 struct l_fixedpt xmt_timestamp;
133 uint32_t key_id;
134 uint8_t message_digest[16];
135 };
136 /*
137 * Leap Second Codes (high order two bits)
138 */
139 #define NO_WARNING 0x00 /* no warning */
140 #define PLUS_SEC 0x40 /* add a second (61 seconds) */
141 #define MINUS_SEC 0x80 /* minus a second (59 seconds) */
142 #define ALARM 0xc0 /* alarm condition (clock unsynchronized) */
143
144 /*
145 * Clock Status Bits that Encode Version
146 */
147 #define NTPVERSION_1 0x08
148 #define VERSIONMASK 0x38
149 #define LEAPMASK 0xc0
150 #ifdef MODEMASK
151 #undef MODEMASK /* Solaris sucks */
152 #endif
153 #define MODEMASK 0x07
154
155 /*
156 * Code values
157 */
158 #define MODE_UNSPEC 0 /* unspecified */
159 #define MODE_SYM_ACT 1 /* symmetric active */
160 #define MODE_SYM_PAS 2 /* symmetric passive */
161 #define MODE_CLIENT 3 /* client */
162 #define MODE_SERVER 4 /* server */
163 #define MODE_BROADCAST 5 /* broadcast */
164 #define MODE_RES1 6 /* reserved */
165 #define MODE_RES2 7 /* reserved */
166
167 /*
168 * Stratum Definitions
169 */
170 #define UNSPECIFIED 0
171 #define PRIM_REF 1 /* radio clock */
172 #define INFO_QUERY 62 /* **** THIS implementation dependent **** */
173 #define INFO_REPLY 63 /* **** THIS implementation dependent **** */
174
175 static void p_sfix(netdissect_options *ndo, const struct s_fixedpt *);
176 static void p_ntp_time(netdissect_options *, const struct l_fixedpt *);
177 static void p_ntp_delta(netdissect_options *, const struct l_fixedpt *, const struct l_fixedpt *);
178
179 static const struct tok ntp_mode_values[] = {
180 { MODE_UNSPEC, "unspecified" },
181 { MODE_SYM_ACT, "symmetric active" },
182 { MODE_SYM_PAS, "symmetric passive" },
183 { MODE_CLIENT, "Client" },
184 { MODE_SERVER, "Server" },
185 { MODE_BROADCAST, "Broadcast" },
186 { MODE_RES1, "Reserved" },
187 { MODE_RES2, "Reserved" },
188 { 0, NULL }
189 };
190
191 static const struct tok ntp_leapind_values[] = {
192 { NO_WARNING, "" },
193 { PLUS_SEC, "+1s" },
194 { MINUS_SEC, "-1s" },
195 { ALARM, "clock unsynchronized" },
196 { 0, NULL }
197 };
198
199 static const struct tok ntp_stratum_values[] = {
200 { UNSPECIFIED, "unspecified" },
201 { PRIM_REF, "primary reference" },
202 { 0, NULL }
203 };
204
205 /*
206 * Print ntp requests
207 */
208 void
ntp_print(netdissect_options * ndo,register const u_char * cp,u_int length)209 ntp_print(netdissect_options *ndo,
210 register const u_char *cp, u_int length)
211 {
212 register const struct ntpdata *bp;
213 int mode, version, leapind;
214
215 bp = (struct ntpdata *)cp;
216
217 ND_TCHECK(bp->status);
218
219 version = (int)(bp->status & VERSIONMASK) >> 3;
220 ND_PRINT((ndo, "NTPv%d", version));
221
222 mode = bp->status & MODEMASK;
223 if (!ndo->ndo_vflag) {
224 ND_PRINT((ndo, ", %s, length %u",
225 tok2str(ntp_mode_values, "Unknown mode", mode),
226 length));
227 return;
228 }
229
230 ND_PRINT((ndo, ", length %u\n\t%s",
231 length,
232 tok2str(ntp_mode_values, "Unknown mode", mode)));
233
234 leapind = bp->status & LEAPMASK;
235 ND_PRINT((ndo, ", Leap indicator: %s (%u)",
236 tok2str(ntp_leapind_values, "Unknown", leapind),
237 leapind));
238
239 ND_TCHECK(bp->stratum);
240 ND_PRINT((ndo, ", Stratum %u (%s)",
241 bp->stratum,
242 tok2str(ntp_stratum_values, (bp->stratum >=2 && bp->stratum<=15) ? "secondary reference" : "reserved", bp->stratum)));
243
244 ND_TCHECK(bp->ppoll);
245 ND_PRINT((ndo, ", poll %u (%us)", bp->ppoll, 1 << bp->ppoll));
246
247 /* Can't ND_TCHECK bp->precision bitfield so bp->distance + 0 instead */
248 ND_TCHECK2(bp->root_delay, 0);
249 ND_PRINT((ndo, ", precision %d", bp->precision));
250
251 ND_TCHECK(bp->root_delay);
252 ND_PRINT((ndo, "\n\tRoot Delay: "));
253 p_sfix(ndo, &bp->root_delay);
254
255 ND_TCHECK(bp->root_dispersion);
256 ND_PRINT((ndo, ", Root dispersion: "));
257 p_sfix(ndo, &bp->root_dispersion);
258
259 ND_TCHECK(bp->refid);
260 ND_PRINT((ndo, ", Reference-ID: "));
261 /* Interpretation depends on stratum */
262 switch (bp->stratum) {
263
264 case UNSPECIFIED:
265 ND_PRINT((ndo, "(unspec)"));
266 break;
267
268 case PRIM_REF:
269 if (fn_printn(ndo, (u_char *)&(bp->refid), 4, ndo->ndo_snapend))
270 goto trunc;
271 break;
272
273 case INFO_QUERY:
274 ND_PRINT((ndo, "%s INFO_QUERY", ipaddr_string(ndo, &(bp->refid))));
275 /* this doesn't have more content */
276 return;
277
278 case INFO_REPLY:
279 ND_PRINT((ndo, "%s INFO_REPLY", ipaddr_string(ndo, &(bp->refid))));
280 /* this is too complex to be worth printing */
281 return;
282
283 default:
284 ND_PRINT((ndo, "%s", ipaddr_string(ndo, &(bp->refid))));
285 break;
286 }
287
288 ND_TCHECK(bp->ref_timestamp);
289 ND_PRINT((ndo, "\n\t Reference Timestamp: "));
290 p_ntp_time(ndo, &(bp->ref_timestamp));
291
292 ND_TCHECK(bp->org_timestamp);
293 ND_PRINT((ndo, "\n\t Originator Timestamp: "));
294 p_ntp_time(ndo, &(bp->org_timestamp));
295
296 ND_TCHECK(bp->rec_timestamp);
297 ND_PRINT((ndo, "\n\t Receive Timestamp: "));
298 p_ntp_time(ndo, &(bp->rec_timestamp));
299
300 ND_TCHECK(bp->xmt_timestamp);
301 ND_PRINT((ndo, "\n\t Transmit Timestamp: "));
302 p_ntp_time(ndo, &(bp->xmt_timestamp));
303
304 ND_PRINT((ndo, "\n\t Originator - Receive Timestamp: "));
305 p_ntp_delta(ndo, &(bp->org_timestamp), &(bp->rec_timestamp));
306
307 ND_PRINT((ndo, "\n\t Originator - Transmit Timestamp: "));
308 p_ntp_delta(ndo, &(bp->org_timestamp), &(bp->xmt_timestamp));
309
310 if ( (sizeof(struct ntpdata) - length) == 16) { /* Optional: key-id */
311 ND_TCHECK(bp->key_id);
312 ND_PRINT((ndo, "\n\tKey id: %u", bp->key_id));
313 } else if ( (sizeof(struct ntpdata) - length) == 0) { /* Optional: key-id + authentication */
314 ND_TCHECK(bp->key_id);
315 ND_PRINT((ndo, "\n\tKey id: %u", bp->key_id));
316 ND_TCHECK2(bp->message_digest, sizeof (bp->message_digest));
317 ND_PRINT((ndo, "\n\tAuthentication: %08x%08x%08x%08x",
318 EXTRACT_32BITS(bp->message_digest),
319 EXTRACT_32BITS(bp->message_digest + 4),
320 EXTRACT_32BITS(bp->message_digest + 8),
321 EXTRACT_32BITS(bp->message_digest + 12)));
322 }
323 return;
324
325 trunc:
326 ND_PRINT((ndo, " [|ntp]"));
327 }
328
329 static void
p_sfix(netdissect_options * ndo,register const struct s_fixedpt * sfp)330 p_sfix(netdissect_options *ndo,
331 register const struct s_fixedpt *sfp)
332 {
333 register int i;
334 register int f;
335 register float ff;
336
337 i = EXTRACT_16BITS(&sfp->int_part);
338 f = EXTRACT_16BITS(&sfp->fraction);
339 ff = f / 65536.0; /* shift radix point by 16 bits */
340 f = ff * 1000000.0; /* Treat fraction as parts per million */
341 ND_PRINT((ndo, "%d.%06d", i, f));
342 }
343
344 #define FMAXINT (4294967296.0) /* floating point rep. of MAXINT */
345
346 static void
p_ntp_time(netdissect_options * ndo,register const struct l_fixedpt * lfp)347 p_ntp_time(netdissect_options *ndo,
348 register const struct l_fixedpt *lfp)
349 {
350 register int32_t i;
351 register uint32_t uf;
352 register uint32_t f;
353 register float ff;
354
355 i = EXTRACT_32BITS(&lfp->int_part);
356 uf = EXTRACT_32BITS(&lfp->fraction);
357 ff = uf;
358 if (ff < 0.0) /* some compilers are buggy */
359 ff += FMAXINT;
360 ff = ff / FMAXINT; /* shift radix point by 32 bits */
361 f = ff * 1000000000.0; /* treat fraction as parts per billion */
362 ND_PRINT((ndo, "%u.%09d", i, f));
363
364 #ifdef HAVE_STRFTIME
365 /*
366 * print the time in human-readable format.
367 */
368 if (i) {
369 time_t seconds = i - JAN_1970;
370 struct tm *tm;
371 char time_buf[128];
372
373 tm = localtime(&seconds);
374 strftime(time_buf, sizeof (time_buf), "%Y/%m/%d %H:%M:%S", tm);
375 ND_PRINT((ndo, " (%s)", time_buf));
376 }
377 #endif
378 }
379
380 /* Prints time difference between *lfp and *olfp */
381 static void
p_ntp_delta(netdissect_options * ndo,register const struct l_fixedpt * olfp,register const struct l_fixedpt * lfp)382 p_ntp_delta(netdissect_options *ndo,
383 register const struct l_fixedpt *olfp,
384 register const struct l_fixedpt *lfp)
385 {
386 register int32_t i;
387 register uint32_t u, uf;
388 register uint32_t ou, ouf;
389 register uint32_t f;
390 register float ff;
391 int signbit;
392
393 u = EXTRACT_32BITS(&lfp->int_part);
394 ou = EXTRACT_32BITS(&olfp->int_part);
395 uf = EXTRACT_32BITS(&lfp->fraction);
396 ouf = EXTRACT_32BITS(&olfp->fraction);
397 if (ou == 0 && ouf == 0) {
398 p_ntp_time(ndo, lfp);
399 return;
400 }
401
402 i = u - ou;
403
404 if (i > 0) { /* new is definitely greater than old */
405 signbit = 0;
406 f = uf - ouf;
407 if (ouf > uf) /* must borrow from high-order bits */
408 i -= 1;
409 } else if (i < 0) { /* new is definitely less than old */
410 signbit = 1;
411 f = ouf - uf;
412 if (uf > ouf) /* must carry into the high-order bits */
413 i += 1;
414 i = -i;
415 } else { /* int_part is zero */
416 if (uf > ouf) {
417 signbit = 0;
418 f = uf - ouf;
419 } else {
420 signbit = 1;
421 f = ouf - uf;
422 }
423 }
424
425 ff = f;
426 if (ff < 0.0) /* some compilers are buggy */
427 ff += FMAXINT;
428 ff = ff / FMAXINT; /* shift radix point by 32 bits */
429 f = ff * 1000000000.0; /* treat fraction as parts per billion */
430 ND_PRINT((ndo, "%s%d.%09d", signbit ? "-" : "+", i, f));
431 }
432
433