The Tcpdump Group git mirrors - tcpdump/blob - print-bfd.c

   1 /*
   2  * Redistribution and use in source and binary forms, with or without
   3  * modification, are permitted provided that: (1) source code
   4  * distributions retain the above copyright notice and this paragraph
   5  * in its entirety, and (2) distributions including binary code include
   6  * the above copyright notice and this paragraph in its entirety in
   7  * the documentation or other materials provided with the distribution.
   8  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND
   9  * WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT
  10  * LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  11  * FOR A PARTICULAR PURPOSE.
  12  *
  13  * Original code by Hannes Gredler (hannes@gredler.at)
  14  */
  15
  16 /* \summary: Bidirectional Forwarding Detection (BFD) printer */
  17
  18 /*
  19  * specification: draft-ietf-bfd-base-01 for version 0,
  20  * RFC 5880 for version 1, and RFC 5881
  21  */
  22
  23 #ifdef HAVE_CONFIG_H
  24 #include <config.h>
  25 #endif
  26
  27 #include "netdissect-stdinc.h"
  28
  29 #include "netdissect.h"
  30 #include "extract.h"
  31
  32 #include "udp.h"
  33
  34 /*
  35  * Control packet, BFDv0, draft-ietf-bfd-base-01
  36  *
  37  *     0                   1                   2                   3
  38  *     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
  39  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  40  *    |Vers |  Diag   |H|D|P|F|C|A|Rsv|  Detect Mult  |    Length     |
  41  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  42  *    |                       My Discriminator                        |
  43  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  44  *    |                      Your Discriminator                       |
  45  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  46  *    |                    Desired Min TX Interval                    |
  47  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  48  *    |                   Required Min RX Interval                    |
  49  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  50  *    |                 Required Min Echo RX Interval                 |
  51  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  52  */
  53
  54 /*
  55  *  Control packet, BFDv1, RFC 5880
  56  *
  57  *     0                   1                   2                   3
  58  *     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
  59  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  60  *    |Vers |  Diag   |Sta|P|F|C|A|D|M|  Detect Mult  |    Length     |
  61  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  62  *    |                       My Discriminator                        |
  63  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  64  *    |                      Your Discriminator                       |
  65  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  66  *    |                    Desired Min TX Interval                    |
  67  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  68  *    |                   Required Min RX Interval                    |
  69  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  70  *    |                 Required Min Echo RX Interval                 |
  71  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  72  */
  73
  74 struct bfd_header_t {
  75     nd_uint8_t  version_diag;
  76     nd_uint8_t  flags;
  77     nd_uint8_t  detect_time_multiplier;
  78     nd_uint8_t  length;
  79     nd_uint32_t my_discriminator;
  80     nd_uint32_t your_discriminator;
  81     nd_uint32_t desired_min_tx_interval;
  82     nd_uint32_t required_min_rx_interval;
  83     nd_uint32_t required_min_echo_interval;
  84 };
  85
  86 /*
  87  *    An optional Authentication Header may be present
  88  *
  89  *     0                   1                   2                   3
  90  *     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
  91  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  92  *    |   Auth Type   |   Auth Len    |    Authentication Data...     |
  93  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  94  */
  95
  96 struct bfd_auth_header_t {
  97     nd_uint8_t auth_type;
  98     nd_uint8_t auth_len;
  99     nd_uint8_t auth_data;
 100     nd_uint8_t dummy; /* minimum 4 bytes */
 101 };
 102
 103 enum auth_type {
 104     AUTH_PASSWORD = 1,
 105     AUTH_MD5      = 2,
 106     AUTH_MET_MD5  = 3,
 107     AUTH_SHA1     = 4,
 108     AUTH_MET_SHA1 = 5
 109 };
 110
 111 static const struct tok bfd_v1_authentication_values[] = {
 112     { AUTH_PASSWORD, "Simple Password" },
 113     { AUTH_MD5,      "Keyed MD5" },
 114     { AUTH_MET_MD5,  "Meticulous Keyed MD5" },
 115     { AUTH_SHA1,     "Keyed SHA1" },
 116     { AUTH_MET_SHA1, "Meticulous Keyed SHA1" },
 117     { 0, NULL }
 118 };
 119
 120 enum auth_length {
 121     AUTH_PASSWORD_FIELD_MIN_LEN = 4,  /* header + password min: 3 + 1 */
 122     AUTH_PASSWORD_FIELD_MAX_LEN = 19, /* header + password max: 3 + 16 */
 123     AUTH_MD5_FIELD_LEN  = 24,
 124     AUTH_MD5_HASH_LEN   = 16,
 125     AUTH_SHA1_FIELD_LEN = 28,
 126     AUTH_SHA1_HASH_LEN  = 20
 127 };
 128
 129 #define BFD_EXTRACT_VERSION(x) (((x)&0xe0)>>5)
 130 #define BFD_EXTRACT_DIAG(x)     ((x)&0x1f)
 131
 132 static const struct tok bfd_diag_values[] = {
 133     { 0, "No Diagnostic" },
 134     { 1, "Control Detection Time Expired" },
 135     { 2, "Echo Function Failed" },
 136     { 3, "Neighbor Signaled Session Down" },
 137     { 4, "Forwarding Plane Reset" },
 138     { 5, "Path Down" },
 139     { 6, "Concatenated Path Down" },
 140     { 7, "Administratively Down" },
 141     { 8, "Reverse Concatenated Path Down" },
 142     { 0, NULL }
 143 };
 144
 145 static const struct tok bfd_port_values[] = {
 146     { BFD_CONTROL_PORT,  "Control" },
 147     { BFD_MULTIHOP_PORT, "Multihop" },
 148     { BFD_LAG_PORT,      "Lag" },
 149     { 0, NULL }
 150 };
 151
 152 #define BFD_FLAG_AUTH 0x04
 153
 154 static const struct tok bfd_v0_flag_values[] = {
 155     { 0x80, "I Hear You" },
 156     { 0x40, "Demand" },
 157     { 0x20, "Poll" },
 158     { 0x10, "Final" },
 159     { 0x08, "Control Plane Independent" },
 160     { BFD_FLAG_AUTH, "Authentication Present" },
 161     { 0x02, "Reserved" },
 162     { 0x01, "Reserved" },
 163     { 0, NULL }
 164 };
 165
 166 static const struct tok bfd_v1_flag_values[] = {
 167     { 0x20, "Poll" },
 168     { 0x10, "Final" },
 169     { 0x08, "Control Plane Independent" },
 170     { BFD_FLAG_AUTH, "Authentication Present" },
 171     { 0x02, "Demand" },
 172     { 0x01, "Multipoint" },
 173     { 0, NULL }
 174 };
 175
 176 static const struct tok bfd_v1_state_values[] = {
 177     { 0, "AdminDown" },
 178     { 1, "Down" },
 179     { 2, "Init" },
 180     { 3, "Up" },
 181     { 0, NULL }
 182 };
 183
 184 static int
 185 auth_print(netdissect_options *ndo, const u_char *pptr)
 186 {
 187         const struct bfd_auth_header_t *bfd_auth_header;
 188         uint8_t auth_type, auth_len;
 189         int i;
 190
 191         pptr += sizeof (struct bfd_header_t);
 192         bfd_auth_header = (const struct bfd_auth_header_t *)pptr;
 193         ND_TCHECK_SIZE(bfd_auth_header);
 194         auth_type = GET_U_1(bfd_auth_header->auth_type);
 195         auth_len = GET_U_1(bfd_auth_header->auth_len);
 196         ND_PRINT("\n\tAuthentication: %s (%u), length: %u",
 197                  tok2str(bfd_v1_authentication_values,"Unknown",auth_type),
 198                  auth_type, auth_len);
 199                 pptr += 2;
 200                 ND_PRINT("\n\t  Auth Key ID: %u", GET_U_1(pptr));
 201
 202         switch(auth_type) {
 203             case AUTH_PASSWORD:
 204 /*
 205  *    Simple Password Authentication Section Format
 206  *
 207  *     0                   1                   2                   3
 208  *     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
 209  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 210  *    |   Auth Type   |   Auth Len    |  Auth Key ID  |  Password...  |
 211  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 212  *    |                              ...                              |
 213  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 214  */
 215                 if (auth_len < AUTH_PASSWORD_FIELD_MIN_LEN ||
 216                     auth_len > AUTH_PASSWORD_FIELD_MAX_LEN) {
 217                     ND_PRINT("[invalid length %u]",
 218                              auth_len);
 219                     break;
 220                 }
 221                 pptr++;
 222                 ND_PRINT(", Password: ");
 223                 /* the length is equal to the password length plus three */
 224                 if (nd_printn(ndo, pptr, auth_len - 3,
 225                               ndo->ndo_snapend))
 226                     goto trunc;
 227                 break;
 228             case AUTH_MD5:
 229             case AUTH_MET_MD5:
 230 /*
 231  *    Keyed MD5 and Meticulous Keyed MD5 Authentication Section Format
 232  *
 233  *     0                   1                   2                   3
 234  *     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
 235  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 236  *    |   Auth Type   |   Auth Len    |  Auth Key ID  |   Reserved    |
 237  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 238  *    |                        Sequence Number                        |
 239  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 240  *    |                      Auth Key/Digest...                       |
 241  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 242  *    |                              ...                              |
 243  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 244  */
 245                 if (auth_len != AUTH_MD5_FIELD_LEN) {
 246                     ND_PRINT("[invalid length %u]",
 247                              auth_len);
 248                     break;
 249                 }
 250                 pptr += 2;
 251                 ND_PRINT(", Sequence Number: 0x%08x", GET_BE_U_4(pptr));
 252                 pptr += 4;
 253                 ND_TCHECK_LEN(pptr, AUTH_MD5_HASH_LEN);
 254                 ND_PRINT("\n\t  Digest: ");
 255                 for(i = 0; i < AUTH_MD5_HASH_LEN; i++)
 256                     ND_PRINT("%02x", GET_U_1(pptr + i));
 257                 break;
 258             case AUTH_SHA1:
 259             case AUTH_MET_SHA1:
 260 /*
 261  *    Keyed SHA1 and Meticulous Keyed SHA1 Authentication Section Format
 262  *
 263  *     0                   1                   2                   3
 264  *     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
 265  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 266  *    |   Auth Type   |   Auth Len    |  Auth Key ID  |   Reserved    |
 267  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 268  *    |                        Sequence Number                        |
 269  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 270  *    |                       Auth Key/Hash...                        |
 271  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 272  *    |                              ...                              |
 273  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 274  */
 275                 if (auth_len != AUTH_SHA1_FIELD_LEN) {
 276                     ND_PRINT("[invalid length %u]",
 277                              auth_len);
 278                     break;
 279                 }
 280                 pptr += 2;
 281                 ND_PRINT(", Sequence Number: 0x%08x", GET_BE_U_4(pptr));
 282                 pptr += 4;
 283                 ND_TCHECK_LEN(pptr, AUTH_SHA1_HASH_LEN);
 284                 ND_PRINT("\n\t  Hash: ");
 285                 for(i = 0; i < AUTH_SHA1_HASH_LEN; i++)
 286                     ND_PRINT("%02x", GET_U_1(pptr + i));
 287                 break;
 288         }
 289         return 0;
 290
 291 trunc:
 292         return 1;
 293 }
 294
 295 void
 296 bfd_print(netdissect_options *ndo, const u_char *pptr,
 297           u_int len, u_int port)
 298 {
 299         ndo->ndo_protocol = "bfd";
 300         if (port == BFD_CONTROL_PORT ||
 301             port == BFD_MULTIHOP_PORT ||
 302             port == BFD_LAG_PORT) {
 303             /*
 304              * Control packet.
 305              */
 306             const struct bfd_header_t *bfd_header;
 307             uint8_t version_diag;
 308             uint8_t version = 0;
 309             uint8_t flags;
 310
 311             bfd_header = (const struct bfd_header_t *)pptr;
 312             ND_TCHECK_SIZE(bfd_header);
 313             version_diag = GET_U_1(bfd_header->version_diag);
 314             version = BFD_EXTRACT_VERSION(version_diag);
 315             flags = GET_U_1(bfd_header->flags);
 316
 317             switch (version) {
 318
 319                 /* BFDv0 */
 320             case 0:
 321                 if (ndo->ndo_vflag < 1)
 322                 {
 323                     ND_PRINT("BFDv0, Control, Flags: [%s], length: %u",
 324                            bittok2str(bfd_v0_flag_values, "none", flags),
 325                            len);
 326                     return;
 327                 }
 328
 329                 ND_PRINT("BFDv0, length: %u\n\tControl, Flags: [%s], Diagnostic: %s (0x%02x)",
 330                        len,
 331                        bittok2str(bfd_v0_flag_values, "none", flags),
 332                        tok2str(bfd_diag_values,"unknown",BFD_EXTRACT_DIAG(version_diag)),
 333                        BFD_EXTRACT_DIAG(version_diag));
 334
 335                 ND_PRINT("\n\tDetection Timer Multiplier: %u (%u ms Detection time), BFD Length: %u",
 336                        GET_U_1(bfd_header->detect_time_multiplier),
 337                        GET_U_1(bfd_header->detect_time_multiplier) * GET_BE_U_4(bfd_header->desired_min_tx_interval)/1000,
 338                        GET_U_1(bfd_header->length));
 339
 340
 341                 ND_PRINT("\n\tMy Discriminator: 0x%08x",
 342                          GET_BE_U_4(bfd_header->my_discriminator));
 343                 ND_PRINT(", Your Discriminator: 0x%08x",
 344                          GET_BE_U_4(bfd_header->your_discriminator));
 345                 ND_PRINT("\n\t  Desired min Tx Interval:    %4u ms",
 346                          GET_BE_U_4(bfd_header->desired_min_tx_interval)/1000);
 347                 ND_PRINT("\n\t  Required min Rx Interval:   %4u ms",
 348                          GET_BE_U_4(bfd_header->required_min_rx_interval)/1000);
 349                 ND_PRINT("\n\t  Required min Echo Interval: %4u ms",
 350                          GET_BE_U_4(bfd_header->required_min_echo_interval)/1000);
 351
 352                 if (flags & BFD_FLAG_AUTH) {
 353                     if (auth_print(ndo, pptr))
 354                         goto trunc;
 355                 }
 356                 break;
 357
 358                 /* BFDv1 */
 359             case 1:
 360                 if (ndo->ndo_vflag < 1)
 361                 {
 362                     ND_PRINT("BFDv1, %s, State %s, Flags: [%s], length: %u",
 363                            tok2str(bfd_port_values, "unknown (%u)", port),
 364                            tok2str(bfd_v1_state_values, "unknown (%u)", (flags & 0xc0) >> 6),
 365                            bittok2str(bfd_v1_flag_values, "none", flags & 0x3f),
 366                            len);
 367                     return;
 368                 }
 369
 370                 ND_PRINT("BFDv1, length: %u\n\t%s, State %s, Flags: [%s], Diagnostic: %s (0x%02x)",
 371                        len,
 372                        tok2str(bfd_port_values, "unknown (%u)", port),
 373                        tok2str(bfd_v1_state_values, "unknown (%u)", (flags & 0xc0) >> 6),
 374                        bittok2str(bfd_v1_flag_values, "none", flags & 0x3f),
 375                        tok2str(bfd_diag_values,"unknown",BFD_EXTRACT_DIAG(version_diag)),
 376                        BFD_EXTRACT_DIAG(version_diag));
 377
 378                 ND_PRINT("\n\tDetection Timer Multiplier: %u (%u ms Detection time), BFD Length: %u",
 379                        GET_U_1(bfd_header->detect_time_multiplier),
 380                        GET_U_1(bfd_header->detect_time_multiplier) * GET_BE_U_4(bfd_header->desired_min_tx_interval)/1000,
 381                        GET_U_1(bfd_header->length));
 382
 383
 384                 ND_PRINT("\n\tMy Discriminator: 0x%08x",
 385                          GET_BE_U_4(bfd_header->my_discriminator));
 386                 ND_PRINT(", Your Discriminator: 0x%08x",
 387                          GET_BE_U_4(bfd_header->your_discriminator));
 388                 ND_PRINT("\n\t  Desired min Tx Interval:    %4u ms",
 389                          GET_BE_U_4(bfd_header->desired_min_tx_interval)/1000);
 390                 ND_PRINT("\n\t  Required min Rx Interval:   %4u ms",
 391                          GET_BE_U_4(bfd_header->required_min_rx_interval)/1000);
 392                 ND_PRINT("\n\t  Required min Echo Interval: %4u ms",
 393                          GET_BE_U_4(bfd_header->required_min_echo_interval)/1000);
 394
 395                 if (flags & BFD_FLAG_AUTH) {
 396                     if (auth_print(ndo, pptr))
 397                         goto trunc;
 398                 }
 399                 break;
 400
 401             default:
 402                 ND_PRINT("BFDv%u, Control, length: %u",
 403                        version,
 404                        len);
 405                 if (ndo->ndo_vflag >= 1) {
 406                     if(!print_unknown_data(ndo, pptr,"\n\t",len))
 407                         return;
 408                 }
 409                 break;
 410             }
 411         } else if (port == BFD_ECHO_PORT) {
 412             /*
 413              * Echo packet.
 414              */
 415             ND_PRINT("BFD, Echo, length: %u",
 416                    len);
 417             if (ndo->ndo_vflag >= 1) {
 418                 if(!print_unknown_data(ndo, pptr,"\n\t",len))
 419                     return;
 420             }
 421         } else {
 422             /*
 423              * Unknown packet type.
 424              */
 425             ND_PRINT("BFD, unknown (%u), length: %u",
 426                    port,
 427                    len);
 428             if (ndo->ndo_vflag >= 1) {
 429                     if(!print_unknown_data(ndo, pptr,"\n\t",len))
 430                             return;
 431             }
 432         }
 433         return;
 434
 435 trunc:
 436         nd_print_trunc(ndo);
 437 }