The Tcpdump Group git mirrors - tcpdump/blob - 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 #ifdef HAVE_CONFIG_H
  28 #include "config.h"
  29 #endif
  30
  31 #include <netdissect-stdinc.h>
  32
  33 #ifdef HAVE_STRFTIME
  34 #include <time.h>
  35 #endif
  36
  37 #include "netdissect.h"
  38 #include "addrtoname.h"
  39 #include "extract.h"
  40
  41 /*
  42  * Based on ntp.h from the U of MD implementation
  43  *      This file is based on Version 2 of the NTP spec (RFC1119).
  44  */
  45
  46 /*
  47  *  Definitions for the masses
  48  */
  49 #define JAN_1970        2208988800U     /* 1970 - 1900 in seconds */
  50
  51 /*
  52  * Structure definitions for NTP fixed point values
  53  *
  54  *    0                   1                   2                   3
  55  *    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
  56  *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  57  *   |                         Integer Part                          |
  58  *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  59  *   |                         Fraction Part                         |
  60  *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  61  *
  62  *    0                   1                   2                   3
  63  *    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
  64  *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  65  *   |            Integer Part       |     Fraction Part             |
  66  *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  67 */
  68 struct l_fixedpt {
  69         uint32_t int_part;
  70         uint32_t fraction;
  71 };
  72
  73 struct s_fixedpt {
  74         uint16_t int_part;
  75         uint16_t fraction;
  76 };
  77
  78 /* rfc2030
  79  *                      1                   2                   3
  80  *  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
  81  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  82  * |LI | VN  |Mode |    Stratum    |     Poll      |   Precision   |
  83  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  84  * |                          Root Delay                           |
  85  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  86  * |                       Root Dispersion                         |
  87  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  88  * |                     Reference Identifier                      |
  89  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  90  * |                                                               |
  91  * |                   Reference Timestamp (64)                    |
  92  * |                                                               |
  93  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  94  * |                                                               |
  95  * |                   Originate Timestamp (64)                    |
  96  * |                                                               |
  97  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  98  * |                                                               |
  99  * |                    Receive Timestamp (64)                     |
 100  * |                                                               |
 101  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 102  * |                                                               |
 103  * |                    Transmit Timestamp (64)                    |
 104  * |                                                               |
 105  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 106  * |                 Key Identifier (optional) (32)                |
 107  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 108  * |                                                               |
 109  * |                                                               |
 110  * |                 Message Digest (optional) (128)               |
 111  * |                                                               |
 112  * |                                                               |
 113  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 114  */
 115
 116 struct ntpdata {
 117         u_char status;          /* status of local clock and leap info */
 118         u_char stratum;         /* Stratum level */
 119         int ppoll:8;            /* poll value */
 120         int precision:8;
 121         struct s_fixedpt root_delay;
 122         struct s_fixedpt root_dispersion;
 123         uint32_t refid;
 124         struct l_fixedpt ref_timestamp;
 125         struct l_fixedpt org_timestamp;
 126         struct l_fixedpt rec_timestamp;
 127         struct l_fixedpt xmt_timestamp;
 128         uint32_t key_id;
 129         uint8_t  message_digest[16];
 130 };
 131 /*
 132  *      Leap Second Codes (high order two bits)
 133  */
 134 #define NO_WARNING      0x00    /* no warning */
 135 #define PLUS_SEC        0x40    /* add a second (61 seconds) */
 136 #define MINUS_SEC       0x80    /* minus a second (59 seconds) */
 137 #define ALARM           0xc0    /* alarm condition (clock unsynchronized) */
 138
 139 /*
 140  *      Clock Status Bits that Encode Version
 141  */
 142 #define NTPVERSION_1    0x08
 143 #define VERSIONMASK     0x38
 144 #define VERSIONSHIFT    3
 145 #define LEAPMASK        0xc0
 146 #define LEAPSHIFT       6
 147 #ifdef MODEMASK
 148 #undef MODEMASK                                 /* Solaris sucks */
 149 #endif
 150 #define MODEMASK        0x07
 151 #define MODESHIFT       0
 152
 153 /*
 154  *      Code values
 155  */
 156 #define MODE_UNSPEC     0       /* unspecified */
 157 #define MODE_SYM_ACT    1       /* symmetric active */
 158 #define MODE_SYM_PAS    2       /* symmetric passive */
 159 #define MODE_CLIENT     3       /* client */
 160 #define MODE_SERVER     4       /* server */
 161 #define MODE_BROADCAST  5       /* broadcast */
 162 #define MODE_CONTROL    6       /* control message */
 163 #define MODE_RES2       7       /* reserved */
 164
 165 /*
 166  *      Stratum Definitions
 167  */
 168 #define UNSPECIFIED     0
 169 #define PRIM_REF        1       /* radio clock */
 170 #define INFO_QUERY      62      /* **** THIS implementation dependent **** */
 171 #define INFO_REPLY      63      /* **** THIS implementation dependent **** */
 172
 173 static void p_sfix(netdissect_options *ndo, const struct s_fixedpt *);
 174 static void p_ntp_time(netdissect_options *, const struct l_fixedpt *);
 175 static void p_ntp_delta(netdissect_options *, const struct l_fixedpt *, const struct l_fixedpt *);
 176 static void p_poll(netdissect_options *, register const int);
 177
 178 static const struct tok ntp_mode_values[] = {
 179     { MODE_UNSPEC,    "unspecified" },
 180     { MODE_SYM_ACT,   "symmetric active" },
 181     { MODE_SYM_PAS,   "symmetric passive" },
 182     { MODE_CLIENT,    "Client" },
 183     { MODE_SERVER,    "Server" },
 184     { MODE_BROADCAST, "Broadcast" },
 185     { MODE_CONTROL,   "Control Message" },
 186     { MODE_RES2,      "Reserved" },
 187     { 0, NULL }
 188 };
 189
 190 static const struct tok ntp_leapind_values[] = {
 191     { NO_WARNING,     "" },
 192     { PLUS_SEC,       "+1s" },
 193     { MINUS_SEC,      "-1s" },
 194     { ALARM,          "clock unsynchronized" },
 195     { 0, NULL }
 196 };
 197
 198 static const struct tok ntp_stratum_values[] = {
 199         { UNSPECIFIED,  "unspecified" },
 200         { PRIM_REF,     "primary reference" },
 201         { 0, NULL }
 202 };
 203
 204 /*
 205  * Print ntp requests
 206  */
 207 void
 208 ntp_print(netdissect_options *ndo,
 209           register const u_char *cp, u_int length)
 210 {
 211         register const struct ntpdata *bp;
 212         int mode, version, leapind;
 213
 214         bp = (const struct ntpdata *)cp;
 215
 216         ND_TCHECK(bp->status);
 217
 218         version = (int)(bp->status & VERSIONMASK) >> VERSIONSHIFT;
 219         ND_PRINT((ndo, "NTPv%d", version));
 220
 221         mode = bp->status & MODEMASK;
 222         if (!ndo->ndo_vflag) {
 223                 ND_PRINT((ndo, ", %s, length %u",
 224                           tok2str(ntp_mode_values, "Unknown mode", mode),
 225                           length));
 226                 return;
 227         }
 228
 229         ND_PRINT((ndo, ", length %u\n\t%s",
 230                   length,
 231                   tok2str(ntp_mode_values, "Unknown mode", mode)));
 232
 233         leapind = bp->status & LEAPMASK;
 234         ND_PRINT((ndo, ", Leap indicator: %s (%u)",
 235                   tok2str(ntp_leapind_values, "Unknown", leapind),
 236                   leapind));
 237
 238         ND_TCHECK(bp->stratum);
 239         ND_PRINT((ndo, ", Stratum %u (%s)",
 240                 bp->stratum,
 241                 tok2str(ntp_stratum_values, (bp->stratum >=2 && bp->stratum<=15) ? "secondary reference" : "reserved", bp->stratum)));
 242
 243         /* Can't ND_TCHECK bp->ppoll bitfield so bp->stratum + 2 instead */
 244         ND_TCHECK2(bp->stratum, 2);
 245         ND_PRINT((ndo, ", poll %d", bp->ppoll));
 246         p_poll(ndo, bp->ppoll);
 247
 248         /* Can't ND_TCHECK bp->precision bitfield so bp->distance + 0 instead */
 249         ND_TCHECK2(bp->root_delay, 0);
 250         ND_PRINT((ndo, ", precision %d", bp->precision));
 251
 252         ND_TCHECK(bp->root_delay);
 253         ND_PRINT((ndo, "\n\tRoot Delay: "));
 254         p_sfix(ndo, &bp->root_delay);
 255
 256         ND_TCHECK(bp->root_dispersion);
 257         ND_PRINT((ndo, ", Root dispersion: "));
 258         p_sfix(ndo, &bp->root_dispersion);
 259
 260         ND_TCHECK(bp->refid);
 261         ND_PRINT((ndo, ", Reference-ID: "));
 262         /* Interpretation depends on stratum */
 263         switch (bp->stratum) {
 264
 265         case UNSPECIFIED:
 266                 ND_PRINT((ndo, "(unspec)"));
 267                 break;
 268
 269         case PRIM_REF:
 270                 if (fn_printn(ndo, (const u_char *)&(bp->refid), 4, ndo->ndo_snapend))
 271                         goto trunc;
 272                 break;
 273
 274         case INFO_QUERY:
 275                 ND_PRINT((ndo, "%s INFO_QUERY", ipaddr_string(ndo, &(bp->refid))));
 276                 /* this doesn't have more content */
 277                 return;
 278
 279         case INFO_REPLY:
 280                 ND_PRINT((ndo, "%s INFO_REPLY", ipaddr_string(ndo, &(bp->refid))));
 281                 /* this is too complex to be worth printing */
 282                 return;
 283
 284         default:
 285                 /* In NTPv4 (RFC 5905) refid is an IPv4 address or first 32 bits of
 286                    MD5 sum of IPv6 address */
 287                 ND_PRINT((ndo, "0x%08x", EXTRACT_32BITS(&bp->refid)));
 288                 break;
 289         }
 290
 291         ND_TCHECK(bp->ref_timestamp);
 292         ND_PRINT((ndo, "\n\t  Reference Timestamp:  "));
 293         p_ntp_time(ndo, &(bp->ref_timestamp));
 294
 295         ND_TCHECK(bp->org_timestamp);
 296         ND_PRINT((ndo, "\n\t  Originator Timestamp: "));
 297         p_ntp_time(ndo, &(bp->org_timestamp));
 298
 299         ND_TCHECK(bp->rec_timestamp);
 300         ND_PRINT((ndo, "\n\t  Receive Timestamp:    "));
 301         p_ntp_time(ndo, &(bp->rec_timestamp));
 302
 303         ND_TCHECK(bp->xmt_timestamp);
 304         ND_PRINT((ndo, "\n\t  Transmit Timestamp:   "));
 305         p_ntp_time(ndo, &(bp->xmt_timestamp));
 306
 307         ND_PRINT((ndo, "\n\t    Originator - Receive Timestamp:  "));
 308         p_ntp_delta(ndo, &(bp->org_timestamp), &(bp->rec_timestamp));
 309
 310         ND_PRINT((ndo, "\n\t    Originator - Transmit Timestamp: "));
 311         p_ntp_delta(ndo, &(bp->org_timestamp), &(bp->xmt_timestamp));
 312
 313         if ( (sizeof(struct ntpdata) - length) == 16) {         /* Optional: key-id */
 314                 ND_TCHECK(bp->key_id);
 315                 ND_PRINT((ndo, "\n\tKey id: %u", EXTRACT_32BITS(&bp->key_id)));
 316         } else if ( (sizeof(struct ntpdata) - length) == 0) {   /* Optional: key-id + authentication */
 317                 ND_TCHECK(bp->key_id);
 318                 ND_PRINT((ndo, "\n\tKey id: %u", EXTRACT_32BITS(&bp->key_id)));
 319                 ND_TCHECK2(bp->message_digest, sizeof (bp->message_digest));
 320                 ND_PRINT((ndo, "\n\tAuthentication: %08x%08x%08x%08x",
 321                                EXTRACT_32BITS(bp->message_digest),
 322                                EXTRACT_32BITS(bp->message_digest + 4),
 323                                EXTRACT_32BITS(bp->message_digest + 8),
 324                                EXTRACT_32BITS(bp->message_digest + 12)));
 325         }
 326         return;
 327
 328 trunc:
 329         ND_PRINT((ndo, " [|ntp]"));
 330 }
 331
 332 static void
 333 p_sfix(netdissect_options *ndo,
 334        register const struct s_fixedpt *sfp)
 335 {
 336         register int i;
 337         register int f;
 338         register double ff;
 339
 340         i = EXTRACT_16BITS(&sfp->int_part);
 341         f = EXTRACT_16BITS(&sfp->fraction);
 342         ff = f / 65536.0;               /* shift radix point by 16 bits */
 343         f = (int)(ff * 1000000.0);      /* Treat fraction as parts per million */
 344         ND_PRINT((ndo, "%d.%06d", i, f));
 345 }
 346
 347 #define FMAXINT (4294967296.0)  /* floating point rep. of MAXINT */
 348
 349 static void
 350 p_ntp_time(netdissect_options *ndo,
 351            register const struct l_fixedpt *lfp)
 352 {
 353         register int32_t i;
 354         register uint32_t uf;
 355         register uint32_t f;
 356         register double ff;
 357
 358         i = EXTRACT_32BITS(&lfp->int_part);
 359         uf = EXTRACT_32BITS(&lfp->fraction);
 360         ff = uf;
 361         if (ff < 0.0)           /* some compilers are buggy */
 362                 ff += FMAXINT;
 363         ff = ff / FMAXINT;                      /* shift radix point by 32 bits */
 364         f = (uint32_t)(ff * 1000000000.0);      /* treat fraction as parts per billion */
 365         ND_PRINT((ndo, "%u.%09d", i, f));
 366
 367 #ifdef HAVE_STRFTIME
 368         /*
 369          * print the UTC time in human-readable format.
 370          */
 371         if (i) {
 372             time_t seconds = i - JAN_1970;
 373             struct tm *tm;
 374             char time_buf[128];
 375
 376             tm = gmtime(&seconds);
 377             /* use ISO 8601 (RFC3339) format */
 378             strftime(time_buf, sizeof (time_buf), "%Y-%m-%dT%H:%M:%S", tm);
 379             ND_PRINT((ndo, " (%s)", time_buf));
 380         }
 381 #endif
 382 }
 383
 384 /* Prints time difference between *lfp and *olfp */
 385 static void
 386 p_ntp_delta(netdissect_options *ndo,
 387             register const struct l_fixedpt *olfp,
 388             register const struct l_fixedpt *lfp)
 389 {
 390         register int32_t i;
 391         register uint32_t u, uf;
 392         register uint32_t ou, ouf;
 393         register uint32_t f;
 394         register double ff;
 395         int signbit;
 396
 397         u = EXTRACT_32BITS(&lfp->int_part);
 398         ou = EXTRACT_32BITS(&olfp->int_part);
 399         uf = EXTRACT_32BITS(&lfp->fraction);
 400         ouf = EXTRACT_32BITS(&olfp->fraction);
 401         if (ou == 0 && ouf == 0) {
 402                 p_ntp_time(ndo, lfp);
 403                 return;
 404         }
 405
 406         i = u - ou;
 407
 408         if (i > 0) {            /* new is definitely greater than old */
 409                 signbit = 0;
 410                 f = uf - ouf;
 411                 if (ouf > uf)   /* must borrow from high-order bits */
 412                         i -= 1;
 413         } else if (i < 0) {     /* new is definitely less than old */
 414                 signbit = 1;
 415                 f = ouf - uf;
 416                 if (uf > ouf)   /* must carry into the high-order bits */
 417                         i += 1;
 418                 i = -i;
 419         } else {                /* int_part is zero */
 420                 if (uf > ouf) {
 421                         signbit = 0;
 422                         f = uf - ouf;
 423                 } else {
 424                         signbit = 1;
 425                         f = ouf - uf;
 426                 }
 427         }
 428
 429         ff = f;
 430         if (ff < 0.0)           /* some compilers are buggy */
 431                 ff += FMAXINT;
 432         ff = ff / FMAXINT;                      /* shift radix point by 32 bits */
 433         f = (uint32_t)(ff * 1000000000.0);      /* treat fraction as parts per billion */
 434         ND_PRINT((ndo, "%s%d.%09d", signbit ? "-" : "+", i, f));
 435 }
 436
 437 /* Prints polling interval in log2 as seconds or fraction of second */
 438 static void
 439 p_poll(netdissect_options *ndo,
 440        register const int poll)
 441 {
 442         if (poll <= -32 || poll >= 32)
 443                 return;
 444
 445         if (poll >= 0)
 446                 ND_PRINT((ndo, " (%us)", 1U << poll));
 447         else
 448                 ND_PRINT((ndo, " (1/%us)", 1U << -poll));
 449 }
 450