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