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