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 /* Length of the NTP message with the mandatory fields ("the header")
 117  * and without any optional fields (extension, Key Identifier,
 118  * Message Digest).
 119  */
 120 #define NTP_MSG_MINLEN 48
 121
 122 struct ntpdata {
 123         u_char status;          /* status of local clock and leap info */
 124         u_char stratum;         /* Stratum level */
 125         int ppoll:8;            /* poll value */
 126         int precision:8;
 127         struct s_fixedpt root_delay;
 128         struct s_fixedpt root_dispersion;
 129         uint32_t refid;
 130         struct l_fixedpt ref_timestamp;
 131         struct l_fixedpt org_timestamp;
 132         struct l_fixedpt rec_timestamp;
 133         struct l_fixedpt xmt_timestamp;
 134         uint32_t key_id;
 135         uint8_t  message_digest[20];
 136 };
 137 /*
 138  *      Leap Second Codes (high order two bits)
 139  */
 140 #define NO_WARNING      0x00    /* no warning */
 141 #define PLUS_SEC        0x40    /* add a second (61 seconds) */
 142 #define MINUS_SEC       0x80    /* minus a second (59 seconds) */
 143 #define ALARM           0xc0    /* alarm condition (clock unsynchronized) */
 144
 145 /*
 146  *      Clock Status Bits that Encode Version
 147  */
 148 #define NTPVERSION_1    0x08
 149 #define VERSIONMASK     0x38
 150 #define VERSIONSHIFT    3
 151 #define LEAPMASK        0xc0
 152 #define LEAPSHIFT       6
 153 #ifdef MODEMASK
 154 #undef MODEMASK                                 /* Solaris sucks */
 155 #endif
 156 #define MODEMASK        0x07
 157 #define MODESHIFT       0
 158
 159 /*
 160  *      Code values
 161  */
 162 #define MODE_UNSPEC     0       /* unspecified */
 163 #define MODE_SYM_ACT    1       /* symmetric active */
 164 #define MODE_SYM_PAS    2       /* symmetric passive */
 165 #define MODE_CLIENT     3       /* client */
 166 #define MODE_SERVER     4       /* server */
 167 #define MODE_BROADCAST  5       /* broadcast */
 168 #define MODE_CONTROL    6       /* control message */
 169 #define MODE_RES2       7       /* reserved */
 170
 171 /*
 172  *      Stratum Definitions
 173  */
 174 #define UNSPECIFIED     0
 175 #define PRIM_REF        1       /* radio clock */
 176 #define INFO_QUERY      62      /* **** THIS implementation dependent **** */
 177 #define INFO_REPLY      63      /* **** THIS implementation dependent **** */
 178
 179 static void p_sfix(netdissect_options *ndo, const struct s_fixedpt *);
 180 static void p_ntp_time(netdissect_options *, const struct l_fixedpt *);
 181 static void p_ntp_delta(netdissect_options *, const struct l_fixedpt *, const struct l_fixedpt *);
 182 static void p_poll(netdissect_options *, register const int);
 183
 184 static const struct tok ntp_mode_values[] = {
 185     { MODE_UNSPEC,    "unspecified" },
 186     { MODE_SYM_ACT,   "symmetric active" },
 187     { MODE_SYM_PAS,   "symmetric passive" },
 188     { MODE_CLIENT,    "Client" },
 189     { MODE_SERVER,    "Server" },
 190     { MODE_BROADCAST, "Broadcast" },
 191     { MODE_CONTROL,   "Control Message" },
 192     { MODE_RES2,      "Reserved" },
 193     { 0, NULL }
 194 };
 195
 196 static const struct tok ntp_leapind_values[] = {
 197     { NO_WARNING,     "" },
 198     { PLUS_SEC,       "+1s" },
 199     { MINUS_SEC,      "-1s" },
 200     { ALARM,          "clock unsynchronized" },
 201     { 0, NULL }
 202 };
 203
 204 static const struct tok ntp_stratum_values[] = {
 205         { UNSPECIFIED,  "unspecified" },
 206         { PRIM_REF,     "primary reference" },
 207         { 0, NULL }
 208 };
 209
 210 /*
 211  * Print ntp requests
 212  */
 213 void
 214 ntp_print(netdissect_options *ndo,
 215           register const u_char *cp, u_int length)
 216 {
 217         register const struct ntpdata *bp;
 218         int mode, version, leapind;
 219
 220         if (length < NTP_MSG_MINLEN) {
 221                 ND_PRINT((ndo, "NTP, length %u", length));
 222                 goto invalid;
 223         }
 224
 225         bp = (const struct ntpdata *)cp;
 226
 227         ND_TCHECK(bp->status);
 228
 229         version = (int)(bp->status & VERSIONMASK) >> VERSIONSHIFT;
 230         ND_PRINT((ndo, "NTPv%d", version));
 231
 232         mode = bp->status & MODEMASK;
 233         if (!ndo->ndo_vflag) {
 234                 ND_PRINT((ndo, ", %s, length %u",
 235                           tok2str(ntp_mode_values, "Unknown mode", mode),
 236                           length));
 237                 return;
 238         }
 239
 240         ND_PRINT((ndo, ", length %u\n\t%s",
 241                   length,
 242                   tok2str(ntp_mode_values, "Unknown mode", mode)));
 243
 244         leapind = bp->status & LEAPMASK;
 245         ND_PRINT((ndo, ", Leap indicator: %s (%u)",
 246                   tok2str(ntp_leapind_values, "Unknown", leapind),
 247                   leapind));
 248
 249         ND_TCHECK(bp->stratum);
 250         ND_PRINT((ndo, ", Stratum %u (%s)",
 251                 bp->stratum,
 252                 tok2str(ntp_stratum_values, (bp->stratum >=2 && bp->stratum<=15) ? "secondary reference" : "reserved", bp->stratum)));
 253
 254         /* Can't ND_TCHECK bp->ppoll bitfield so bp->stratum + 2 instead */
 255         ND_TCHECK2(bp->stratum, 2);
 256         ND_PRINT((ndo, ", poll %d", bp->ppoll));
 257         p_poll(ndo, bp->ppoll);
 258
 259         /* Can't ND_TCHECK bp->precision bitfield so bp->distance + 0 instead */
 260         ND_TCHECK2(bp->root_delay, 0);
 261         ND_PRINT((ndo, ", precision %d", bp->precision));
 262
 263         ND_TCHECK(bp->root_delay);
 264         ND_PRINT((ndo, "\n\tRoot Delay: "));
 265         p_sfix(ndo, &bp->root_delay);
 266
 267         ND_TCHECK(bp->root_dispersion);
 268         ND_PRINT((ndo, ", Root dispersion: "));
 269         p_sfix(ndo, &bp->root_dispersion);
 270
 271         ND_TCHECK(bp->refid);
 272         ND_PRINT((ndo, ", Reference-ID: "));
 273         /* Interpretation depends on stratum */
 274         switch (bp->stratum) {
 275
 276         case UNSPECIFIED:
 277                 ND_PRINT((ndo, "(unspec)"));
 278                 break;
 279
 280         case PRIM_REF:
 281                 if (fn_printn(ndo, (const u_char *)&(bp->refid), 4, ndo->ndo_snapend))
 282                         goto trunc;
 283                 break;
 284
 285         case INFO_QUERY:
 286                 ND_PRINT((ndo, "%s INFO_QUERY", ipaddr_string(ndo, &(bp->refid))));
 287                 /* this doesn't have more content */
 288                 return;
 289
 290         case INFO_REPLY:
 291                 ND_PRINT((ndo, "%s INFO_REPLY", ipaddr_string(ndo, &(bp->refid))));
 292                 /* this is too complex to be worth printing */
 293                 return;
 294
 295         default:
 296                 /* In NTPv4 (RFC 5905) refid is an IPv4 address or first 32 bits of
 297                    MD5 sum of IPv6 address */
 298                 ND_PRINT((ndo, "0x%08x", EXTRACT_32BITS(&bp->refid)));
 299                 break;
 300         }
 301
 302         ND_TCHECK(bp->ref_timestamp);
 303         ND_PRINT((ndo, "\n\t  Reference Timestamp:  "));
 304         p_ntp_time(ndo, &(bp->ref_timestamp));
 305
 306         ND_TCHECK(bp->org_timestamp);
 307         ND_PRINT((ndo, "\n\t  Originator Timestamp: "));
 308         p_ntp_time(ndo, &(bp->org_timestamp));
 309
 310         ND_TCHECK(bp->rec_timestamp);
 311         ND_PRINT((ndo, "\n\t  Receive Timestamp:    "));
 312         p_ntp_time(ndo, &(bp->rec_timestamp));
 313
 314         ND_TCHECK(bp->xmt_timestamp);
 315         ND_PRINT((ndo, "\n\t  Transmit Timestamp:   "));
 316         p_ntp_time(ndo, &(bp->xmt_timestamp));
 317
 318         ND_PRINT((ndo, "\n\t    Originator - Receive Timestamp:  "));
 319         p_ntp_delta(ndo, &(bp->org_timestamp), &(bp->rec_timestamp));
 320
 321         ND_PRINT((ndo, "\n\t    Originator - Transmit Timestamp: "));
 322         p_ntp_delta(ndo, &(bp->org_timestamp), &(bp->xmt_timestamp));
 323
 324         /* FIXME: this code is not aware of any extension fields */
 325         if (length == NTP_MSG_MINLEN + 4) {     /* Optional: key-id (crypto-NAK) */
 326                 ND_TCHECK(bp->key_id);
 327                 ND_PRINT((ndo, "\n\tKey id: %u", EXTRACT_32BITS(&bp->key_id)));
 328         } else if (length == NTP_MSG_MINLEN + 4 + 16) {         /* Optional: key-id + 128-bit digest */
 329                 ND_TCHECK(bp->key_id);
 330                 ND_PRINT((ndo, "\n\tKey id: %u", EXTRACT_32BITS(&bp->key_id)));
 331                 ND_TCHECK2(bp->message_digest, 16);
 332                 ND_PRINT((ndo, "\n\tAuthentication: %08x%08x%08x%08x",
 333                                EXTRACT_32BITS(bp->message_digest),
 334                                EXTRACT_32BITS(bp->message_digest + 4),
 335                                EXTRACT_32BITS(bp->message_digest + 8),
 336                                EXTRACT_32BITS(bp->message_digest + 12)));
 337         } else if (length == NTP_MSG_MINLEN + 4 + 20) {         /* Optional: key-id + 160-bit digest */
 338                 ND_TCHECK(bp->key_id);
 339                 ND_PRINT((ndo, "\n\tKey id: %u", EXTRACT_32BITS(&bp->key_id)));
 340                 ND_TCHECK2(bp->message_digest, 20);
 341                 ND_PRINT((ndo, "\n\tAuthentication: %08x%08x%08x%08x%08x",
 342                                EXTRACT_32BITS(bp->message_digest),
 343                                EXTRACT_32BITS(bp->message_digest + 4),
 344                                EXTRACT_32BITS(bp->message_digest + 8),
 345                                EXTRACT_32BITS(bp->message_digest + 12),
 346                                EXTRACT_32BITS(bp->message_digest + 16)));
 347         } else if (length > NTP_MSG_MINLEN) {
 348                 ND_PRINT((ndo, "\n\t(%u more bytes after the header)", length - NTP_MSG_MINLEN));
 349         }
 350         return;
 351
 352 invalid:
 353         ND_PRINT((ndo, " %s", istr));
 354         ND_TCHECK2(*cp, length);
 355         return;
 356
 357 trunc:
 358         ND_PRINT((ndo, " [|ntp]"));
 359 }
 360
 361 static void
 362 p_sfix(netdissect_options *ndo,
 363        register const struct s_fixedpt *sfp)
 364 {
 365         register int i;
 366         register int f;
 367         register double ff;
 368
 369         i = EXTRACT_16BITS(&sfp->int_part);
 370         f = EXTRACT_16BITS(&sfp->fraction);
 371         ff = f / 65536.0;               /* shift radix point by 16 bits */
 372         f = (int)(ff * 1000000.0);      /* Treat fraction as parts per million */
 373         ND_PRINT((ndo, "%d.%06d", i, f));
 374 }
 375
 376 #define FMAXINT (4294967296.0)  /* floating point rep. of MAXINT */
 377
 378 static void
 379 p_ntp_time(netdissect_options *ndo,
 380            register const struct l_fixedpt *lfp)
 381 {
 382         register int32_t i;
 383         register uint32_t uf;
 384         register uint32_t f;
 385         register double ff;
 386
 387         i = EXTRACT_32BITS(&lfp->int_part);
 388         uf = EXTRACT_32BITS(&lfp->fraction);
 389         ff = uf;
 390         if (ff < 0.0)           /* some compilers are buggy */
 391                 ff += FMAXINT;
 392         ff = ff / FMAXINT;                      /* shift radix point by 32 bits */
 393         f = (uint32_t)(ff * 1000000000.0);      /* treat fraction as parts per billion */
 394         ND_PRINT((ndo, "%u.%09d", i, f));
 395
 396 #ifdef HAVE_STRFTIME
 397         /*
 398          * print the UTC time in human-readable format.
 399          */
 400         if (i) {
 401             time_t seconds = i - JAN_1970;
 402             struct tm *tm;
 403             char time_buf[128];
 404
 405             tm = gmtime(&seconds);
 406             /* use ISO 8601 (RFC3339) format */
 407             strftime(time_buf, sizeof (time_buf), "%Y-%m-%dT%H:%M:%S", tm);
 408             ND_PRINT((ndo, " (%s)", time_buf));
 409         }
 410 #endif
 411 }
 412
 413 /* Prints time difference between *lfp and *olfp */
 414 static void
 415 p_ntp_delta(netdissect_options *ndo,
 416             register const struct l_fixedpt *olfp,
 417             register const struct l_fixedpt *lfp)
 418 {
 419         register int32_t i;
 420         register uint32_t u, uf;
 421         register uint32_t ou, ouf;
 422         register uint32_t f;
 423         register double ff;
 424         int signbit;
 425
 426         u = EXTRACT_32BITS(&lfp->int_part);
 427         ou = EXTRACT_32BITS(&olfp->int_part);
 428         uf = EXTRACT_32BITS(&lfp->fraction);
 429         ouf = EXTRACT_32BITS(&olfp->fraction);
 430         if (ou == 0 && ouf == 0) {
 431                 p_ntp_time(ndo, lfp);
 432                 return;
 433         }
 434
 435         i = u - ou;
 436
 437         if (i > 0) {            /* new is definitely greater than old */
 438                 signbit = 0;
 439                 f = uf - ouf;
 440                 if (ouf > uf)   /* must borrow from high-order bits */
 441                         i -= 1;
 442         } else if (i < 0) {     /* new is definitely less than old */
 443                 signbit = 1;
 444                 f = ouf - uf;
 445                 if (uf > ouf)   /* must carry into the high-order bits */
 446                         i += 1;
 447                 i = -i;
 448         } else {                /* int_part is zero */
 449                 if (uf > ouf) {
 450                         signbit = 0;
 451                         f = uf - ouf;
 452                 } else {
 453                         signbit = 1;
 454                         f = ouf - uf;
 455                 }
 456         }
 457
 458         ff = f;
 459         if (ff < 0.0)           /* some compilers are buggy */
 460                 ff += FMAXINT;
 461         ff = ff / FMAXINT;                      /* shift radix point by 32 bits */
 462         f = (uint32_t)(ff * 1000000000.0);      /* treat fraction as parts per billion */
 463         ND_PRINT((ndo, "%s%d.%09d", signbit ? "-" : "+", i, f));
 464 }
 465
 466 /* Prints polling interval in log2 as seconds or fraction of second */
 467 static void
 468 p_poll(netdissect_options *ndo,
 469        register const int poll)
 470 {
 471         if (poll <= -32 || poll >= 32)
 472                 return;
 473
 474         if (poll >= 0)
 475                 ND_PRINT((ndo, " (%us)", 1U << poll));
 476         else
 477                 ND_PRINT((ndo, " (1/%us)", 1U << -poll));
 478 }
 479