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 /*
  28  * specification:
  29  *
  30  * RFC 1119 - NTPv2
  31  * RFC 1305 - NTPv3
  32  * RFC 5905 - NTPv4
  33  */
  34
  35 #ifdef HAVE_CONFIG_H
  36 #include <config.h>
  37 #endif
  38
  39 #include "netdissect-stdinc.h"
  40
  41 #include "netdissect.h"
  42 #include "addrtoname.h"
  43 #include "extract.h"
  44
  45 #include "ntp.h"
  46
  47 /*
  48  * Based on ntp.h from the U of MD implementation
  49  *      This file is based on Version 2 of the NTP spec (RFC1119).
  50  */
  51
  52 /* rfc2030
  53  *                      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  * |LI | VN  |Mode |    Stratum    |     Poll      |   Precision   |
  57  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  58  * |                          Root Delay                           |
  59  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  60  * |                       Root Dispersion                         |
  61  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  62  * |                     Reference Identifier                      |
  63  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  64  * |                                                               |
  65  * |                   Reference Timestamp (64)                    |
  66  * |                                                               |
  67  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  68  * |                                                               |
  69  * |                   Originate Timestamp (64)                    |
  70  * |                                                               |
  71  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  72  * |                                                               |
  73  * |                    Receive Timestamp (64)                     |
  74  * |                                                               |
  75  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  76  * |                                                               |
  77  * |                    Transmit Timestamp (64)                    |
  78  * |                                                               |
  79  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  80  * |                 Key Identifier (optional) (32)                |
  81  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  82  * |                                                               |
  83  * |                                                               |
  84  * |                 Message Digest (optional) (128)               |
  85  * |                                                               |
  86  * |                                                               |
  87  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  88  */
  89
  90 /* Length of the NTP data message with the mandatory fields ("the header")
  91  * and without any optional fields (extension, Key Identifier,
  92  * Message Digest).
  93  */
  94 #define NTP_TIMEMSG_MINLEN 48U
  95
  96 struct ntp_time_data {
  97         nd_uint8_t status;              /* status of local clock and leap info */
  98         nd_uint8_t stratum;             /* Stratum level */
  99         nd_int8_t ppoll;                /* poll value */
 100         nd_int8_t precision;
 101         struct s_fixedpt root_delay;
 102         struct s_fixedpt root_dispersion;
 103         nd_uint32_t refid;
 104         struct l_fixedpt ref_timestamp;
 105         struct l_fixedpt org_timestamp;
 106         struct l_fixedpt rec_timestamp;
 107         struct l_fixedpt xmt_timestamp;
 108         nd_uint32_t key_id;
 109         nd_uint8_t  message_digest[20];
 110 };
 111 /*
 112  *      Leap Second Codes (high order two bits)
 113  */
 114 #define NO_WARNING      0x00    /* no warning */
 115 #define PLUS_SEC        0x40    /* add a second (61 seconds) */
 116 #define MINUS_SEC       0x80    /* minus a second (59 seconds) */
 117 #define ALARM           0xc0    /* alarm condition (clock unsynchronized) */
 118
 119 /*
 120  *      Clock Status Bits that Encode Version
 121  */
 122 #define NTPVERSION_1    0x08
 123 #define VERSIONMASK     0x38
 124 #define VERSIONSHIFT    3
 125 #define LEAPMASK        0xc0
 126 #define LEAPSHIFT       6
 127 #ifdef MODEMASK
 128 #undef MODEMASK                                 /* Solaris sucks */
 129 #endif
 130 #define MODEMASK        0x07
 131 #define MODESHIFT       0
 132
 133 /*
 134  *      Code values
 135  */
 136 #define MODE_UNSPEC     0       /* unspecified */
 137 #define MODE_SYM_ACT    1       /* symmetric active */
 138 #define MODE_SYM_PAS    2       /* symmetric passive */
 139 #define MODE_CLIENT     3       /* client */
 140 #define MODE_SERVER     4       /* server */
 141 #define MODE_BROADCAST  5       /* broadcast */
 142 #define MODE_CONTROL    6       /* control message */
 143 #define MODE_RES2       7       /* reserved */
 144
 145 /*
 146  *      Stratum Definitions
 147  */
 148 #define UNSPECIFIED     0
 149 #define PRIM_REF        1       /* radio clock */
 150 #define INFO_QUERY      62      /* **** THIS implementation dependent **** */
 151 #define INFO_REPLY      63      /* **** THIS implementation dependent **** */
 152
 153 static void p_sfix(netdissect_options *ndo, const struct s_fixedpt *);
 154 static void p_ntp_delta(netdissect_options *, const struct l_fixedpt *, const struct l_fixedpt *);
 155 static void p_poll(netdissect_options *, const int);
 156
 157 static const struct tok ntp_mode_values[] = {
 158     { MODE_UNSPEC,    "unspecified" },
 159     { MODE_SYM_ACT,   "symmetric active" },
 160     { MODE_SYM_PAS,   "symmetric passive" },
 161     { MODE_CLIENT,    "Client" },
 162     { MODE_SERVER,    "Server" },
 163     { MODE_BROADCAST, "Broadcast" },
 164     { MODE_CONTROL,   "Control Message" },
 165     { MODE_RES2,      "Reserved" },
 166     { 0, NULL }
 167 };
 168
 169 static const struct tok ntp_leapind_values[] = {
 170     { NO_WARNING,     "" },
 171     { PLUS_SEC,       "+1s" },
 172     { MINUS_SEC,      "-1s" },
 173     { ALARM,          "clock unsynchronized" },
 174     { 0, NULL }
 175 };
 176
 177 static const struct tok ntp_stratum_values[] = {
 178         { UNSPECIFIED,  "unspecified" },
 179         { PRIM_REF,     "primary reference" },
 180         { 0, NULL }
 181 };
 182
 183 /* draft-ietf-ntp-mode-6-cmds-02
 184  *  0                   1                   2                   3
 185  *  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
 186  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 187  * |LI |  VN |Mode |R|E|M| OpCode  |       Sequence Number         |
 188  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 189  * |            Status             |       Association ID          |
 190  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 191  * |            Offset             |            Count              |
 192  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 193  * |                                                               |
 194  * /                    Data (up to 468 bytes)                     /
 195  * |                                                               |
 196  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 197  * |                    Padding (optional)                         |
 198  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 199  * |                                                               |
 200  * /              Authenticator (optional, 96 bytes)               /
 201  * |                                                               |
 202  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 203  *
 204  *               Figure 1: NTP Control Message Header
 205  */
 206
 207 /* Length of the NTP control message with the mandatory fields ("the header")
 208  * and without any optional fields (Data, Padding, Authenticator).
 209  */
 210 #define NTP_CTRLMSG_MINLEN 12U
 211
 212 struct ntp_control_data {
 213         nd_uint8_t      magic;          /* LI, VN, Mode */
 214         nd_uint8_t      control;        /* R, E, M, OpCode */
 215         nd_uint16_t     sequence;       /* Sequence Number */
 216         nd_uint16_t     status;         /* Status */
 217         nd_uint16_t     assoc;          /* Association ID */
 218         nd_uint16_t     offset;         /* Offset */
 219         nd_uint16_t     count;          /* Count */
 220         nd_uint8_t      data[564];      /* Data, [Padding, [Authenticator]] */
 221 };
 222
 223 /*
 224  * Print NTP time requests and responses
 225  */
 226 static void
 227 ntp_time_print(netdissect_options *ndo,
 228                const struct ntp_time_data *bp, u_int length)
 229 {
 230         uint8_t stratum;
 231
 232         if (length < NTP_TIMEMSG_MINLEN)
 233                 goto invalid;
 234
 235         stratum = GET_U_1(bp->stratum);
 236         ND_PRINT(", Stratum %u (%s)",
 237                 stratum,
 238                 tok2str(ntp_stratum_values, (stratum >=2 && stratum<=15) ? "secondary reference" : "reserved", stratum));
 239
 240         ND_PRINT(", poll %d", GET_S_1(bp->ppoll));
 241         p_poll(ndo, GET_S_1(bp->ppoll));
 242
 243         ND_PRINT(", precision %d", GET_S_1(bp->precision));
 244
 245         ND_TCHECK_SIZE(&bp->root_delay);
 246         ND_PRINT("\n\tRoot Delay: ");
 247         p_sfix(ndo, &bp->root_delay);
 248
 249         ND_TCHECK_SIZE(&bp->root_dispersion);
 250         ND_PRINT(", Root dispersion: ");
 251         p_sfix(ndo, &bp->root_dispersion);
 252
 253         ND_TCHECK_4(bp->refid);
 254         ND_PRINT(", Reference-ID: ");
 255         /* Interpretation depends on stratum */
 256         switch (stratum) {
 257
 258         case UNSPECIFIED:
 259                 ND_PRINT("(unspec)");
 260                 break;
 261
 262         case PRIM_REF:
 263                 if (nd_printn(ndo, (const u_char *)&(bp->refid), 4, ndo->ndo_snapend))
 264                         goto trunc;
 265                 break;
 266
 267         case INFO_QUERY:
 268                 ND_PRINT("%s INFO_QUERY", GET_IPADDR_STRING(bp->refid));
 269                 /* this doesn't have more content */
 270                 return;
 271
 272         case INFO_REPLY:
 273                 ND_PRINT("%s INFO_REPLY", GET_IPADDR_STRING(bp->refid));
 274                 /* this is too complex to be worth printing */
 275                 return;
 276
 277         default:
 278                 /* In NTPv4 (RFC 5905) refid is an IPv4 address or first 32 bits of
 279                    MD5 sum of IPv6 address */
 280                 ND_PRINT("0x%08x", GET_BE_U_4(bp->refid));
 281                 break;
 282         }
 283
 284         ND_TCHECK_SIZE(&bp->ref_timestamp);
 285         ND_PRINT("\n\t  Reference Timestamp:  ");
 286         p_ntp_time(ndo, &(bp->ref_timestamp));
 287
 288         ND_TCHECK_SIZE(&bp->org_timestamp);
 289         ND_PRINT("\n\t  Originator Timestamp: ");
 290         p_ntp_time(ndo, &(bp->org_timestamp));
 291
 292         ND_TCHECK_SIZE(&bp->rec_timestamp);
 293         ND_PRINT("\n\t  Receive Timestamp:    ");
 294         p_ntp_time(ndo, &(bp->rec_timestamp));
 295
 296         ND_TCHECK_SIZE(&bp->xmt_timestamp);
 297         ND_PRINT("\n\t  Transmit Timestamp:   ");
 298         p_ntp_time(ndo, &(bp->xmt_timestamp));
 299
 300         ND_PRINT("\n\t    Originator - Receive Timestamp:  ");
 301         p_ntp_delta(ndo, &(bp->org_timestamp), &(bp->rec_timestamp));
 302
 303         ND_PRINT("\n\t    Originator - Transmit Timestamp: ");
 304         p_ntp_delta(ndo, &(bp->org_timestamp), &(bp->xmt_timestamp));
 305
 306         /* FIXME: this code is not aware of any extension fields */
 307         if (length == NTP_TIMEMSG_MINLEN + 4) { /* Optional: key-id (crypto-NAK) */
 308                 ND_PRINT("\n\tKey id: %u", GET_BE_U_4(bp->key_id));
 309         } else if (length == NTP_TIMEMSG_MINLEN + 4 + 16) {     /* Optional: key-id + 128-bit digest */
 310                 ND_PRINT("\n\tKey id: %u", GET_BE_U_4(bp->key_id));
 311                 ND_TCHECK_LEN(bp->message_digest, 16);
 312                 ND_PRINT("\n\tAuthentication: %08x%08x%08x%08x",
 313                          GET_BE_U_4(bp->message_digest),
 314                          GET_BE_U_4(bp->message_digest + 4),
 315                          GET_BE_U_4(bp->message_digest + 8),
 316                          GET_BE_U_4(bp->message_digest + 12));
 317         } else if (length == NTP_TIMEMSG_MINLEN + 4 + 20) {     /* Optional: key-id + 160-bit digest */
 318                 ND_PRINT("\n\tKey id: %u", GET_BE_U_4(bp->key_id));
 319                 ND_TCHECK_LEN(bp->message_digest, 20);
 320                 ND_PRINT("\n\tAuthentication: %08x%08x%08x%08x%08x",
 321                          GET_BE_U_4(bp->message_digest),
 322                          GET_BE_U_4(bp->message_digest + 4),
 323                          GET_BE_U_4(bp->message_digest + 8),
 324                          GET_BE_U_4(bp->message_digest + 12),
 325                          GET_BE_U_4(bp->message_digest + 16));
 326         } else if (length > NTP_TIMEMSG_MINLEN) {
 327                 ND_PRINT("\n\t(%u more bytes after the header)", length - NTP_TIMEMSG_MINLEN);
 328         }
 329         return;
 330
 331 invalid:
 332         nd_print_invalid(ndo);
 333         ND_TCHECK_LEN(bp, length);
 334         return;
 335
 336 trunc:
 337         nd_print_trunc(ndo);
 338 }
 339
 340 /*
 341  * Print NTP control message requests and responses
 342  */
 343 static void
 344 ntp_control_print(netdissect_options *ndo,
 345                   const struct ntp_control_data *cd, u_int length)
 346 {
 347         uint8_t control, R, E, M, opcode;
 348         uint16_t sequence, status, assoc, offset, count;
 349
 350         if (length < NTP_CTRLMSG_MINLEN)
 351                 goto invalid;
 352
 353         control = GET_U_1(cd->control);
 354         R = (control & 0x80) != 0;
 355         E = (control & 0x40) != 0;
 356         M = (control & 0x20) != 0;
 357         opcode = control & 0x1f;
 358         ND_PRINT(", %s, %s, %s, OpCode=%u\n",
 359                   R ? "Response" : "Request", E ? "Error" : "OK",
 360                   M ? "More" : "Last", opcode);
 361
 362         sequence = GET_BE_U_2(cd->sequence);
 363         ND_PRINT("\tSequence=%hu", sequence);
 364
 365         status = GET_BE_U_2(cd->status);
 366         ND_PRINT(", Status=%#hx", status);
 367
 368         assoc = GET_BE_U_2(cd->assoc);
 369         ND_PRINT(", Assoc.=%hu", assoc);
 370
 371         offset = GET_BE_U_2(cd->offset);
 372         ND_PRINT(", Offset=%hu", offset);
 373
 374         count = GET_BE_U_2(cd->count);
 375         ND_PRINT(", Count=%hu", count);
 376
 377         if (NTP_CTRLMSG_MINLEN + count > length)
 378                 goto invalid;
 379         if (count != 0) {
 380                 ND_TCHECK_LEN(cd->data, count);
 381                 ND_PRINT("\n\tTO-BE-DONE: data not interpreted");
 382         }
 383         return;
 384
 385 invalid:
 386         nd_print_invalid(ndo);
 387         ND_TCHECK_LEN(cd, length);
 388         return;
 389
 390 trunc:
 391         nd_print_trunc(ndo);
 392 }
 393
 394 union ntpdata {
 395         struct ntp_time_data    td;
 396         struct ntp_control_data cd;
 397 };
 398
 399 /*
 400  * Print NTP requests, handling the common VN, LI, and Mode
 401  */
 402 void
 403 ntp_print(netdissect_options *ndo,
 404           const u_char *cp, u_int length)
 405 {
 406         const union ntpdata *bp = (const union ntpdata *)cp;
 407         u_int mode, version, leapind;
 408         uint8_t status;
 409
 410         ndo->ndo_protocol = "ntp";
 411         status = GET_U_1(bp->td.status);
 412
 413         version = (status & VERSIONMASK) >> VERSIONSHIFT;
 414         ND_PRINT("NTPv%u", version);
 415
 416         mode = (status & MODEMASK) >> MODESHIFT;
 417         if (!ndo->ndo_vflag) {
 418                 ND_PRINT(", %s, length %u",
 419                          tok2str(ntp_mode_values, "Unknown mode", mode),
 420                          length);
 421                 return;
 422         }
 423
 424         ND_PRINT(", %s, length %u\n",
 425                   tok2str(ntp_mode_values, "Unknown mode", mode), length);
 426
 427         /* leapind = (status & LEAPMASK) >> LEAPSHIFT; */
 428         leapind = (status & LEAPMASK);
 429         ND_PRINT("\tLeap indicator: %s (%u)",
 430                  tok2str(ntp_leapind_values, "Unknown", leapind),
 431                  leapind);
 432
 433         switch (mode) {
 434
 435         case MODE_UNSPEC:
 436         case MODE_SYM_ACT:
 437         case MODE_SYM_PAS:
 438         case MODE_CLIENT:
 439         case MODE_SERVER:
 440         case MODE_BROADCAST:
 441                 ntp_time_print(ndo, &bp->td, length);
 442                 break;
 443
 444         case MODE_CONTROL:
 445                 ntp_control_print(ndo, &bp->cd, length);
 446                 break;
 447
 448         default:
 449                 break;                  /* XXX: not implemented! */
 450         }
 451 }
 452
 453 static void
 454 p_sfix(netdissect_options *ndo,
 455        const struct s_fixedpt *sfp)
 456 {
 457         int i;
 458         int f;
 459         double ff;
 460
 461         i = GET_BE_U_2(sfp->int_part);
 462         f = GET_BE_U_2(sfp->fraction);
 463         ff = f / 65536.0;               /* shift radix point by 16 bits */
 464         f = (int)(ff * 1000000.0);      /* Treat fraction as parts per million */
 465         ND_PRINT("%d.%06d", i, f);
 466 }
 467
 468 /* Prints time difference between *lfp and *olfp */
 469 static void
 470 p_ntp_delta(netdissect_options *ndo,
 471             const struct l_fixedpt *olfp,
 472             const struct l_fixedpt *lfp)
 473 {
 474         uint32_t u, uf;
 475         uint32_t ou, ouf;
 476         uint32_t i;
 477         uint32_t f;
 478         double ff;
 479         int signbit;
 480
 481         u = GET_BE_U_4(lfp->int_part);
 482         ou = GET_BE_U_4(olfp->int_part);
 483         uf = GET_BE_U_4(lfp->fraction);
 484         ouf = GET_BE_U_4(olfp->fraction);
 485         if (ou == 0 && ouf == 0) {
 486                 p_ntp_time(ndo, lfp);
 487                 return;
 488         }
 489
 490         if (u > ou) {           /* new is definitely greater than old */
 491                 signbit = 0;
 492                 i = u - ou;
 493                 f = uf - ouf;
 494                 if (ouf > uf)   /* must borrow from high-order bits */
 495                         i -= 1;
 496         } else if (u < ou) {    /* new is definitely less than old */
 497                 signbit = 1;
 498                 i = ou - u;
 499                 f = ouf - uf;
 500                 if (uf > ouf)   /* must borrow from the high-order bits */
 501                         i -= 1;
 502         } else {                /* int_part is zero */
 503                 i = 0;
 504                 if (uf > ouf) {
 505                         signbit = 0;
 506                         f = uf - ouf;
 507                 } else {
 508                         signbit = 1;
 509                         f = ouf - uf;
 510                 }
 511         }
 512
 513         ff = f;
 514         if (ff < 0.0)           /* some compilers are buggy */
 515                 ff += FMAXINT;
 516         ff = ff / FMAXINT;                      /* shift radix point by 32 bits */
 517         f = (uint32_t)(ff * 1000000000.0);      /* treat fraction as parts per billion */
 518         ND_PRINT("%s%u.%09u", signbit ? "-" : "+", i, f);
 519 }
 520
 521 /* Prints polling interval in log2 as seconds or fraction of second */
 522 static void
 523 p_poll(netdissect_options *ndo,
 524        const int poll_interval)
 525 {
 526         if (poll_interval <= -32 || poll_interval >= 32)
 527                 return;
 528
 529         if (poll_interval >= 0)
 530                 ND_PRINT(" (%us)", 1U << poll_interval);
 531         else
 532                 ND_PRINT(" (1/%us)", 1U << -poll_interval);
 533 }
 534