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 /* specification: RFC 5880 (for version 1) and RFC 5881 */
  19
  20 #ifdef HAVE_CONFIG_H
  21 #include <config.h>
  22 #endif
  23
  24 #include "netdissect-stdinc.h"
  25
  26 #include "netdissect.h"
  27 #include "extract.h"
  28
  29 #include "udp.h"
  30
  31 /*
  32  * Control packet, BFDv0, draft-katz-ward-bfd-01.txt
  33  *
  34  *     0                   1                   2                   3
  35  *     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
  36  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  37  *    |Vers |  Diag   |H|D|P|F| Rsvd  |  Detect Mult  |    Length     |
  38  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  39  *    |                       My Discriminator                        |
  40  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  41  *    |                      Your Discriminator                       |
  42  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  43  *    |                    Desired Min TX Interval                    |
  44  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  45  *    |                   Required Min RX Interval                    |
  46  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  47  *    |                 Required Min Echo RX Interval                 |
  48  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  49  */
  50
  51 /*
  52  *  Control packet, BFDv1, RFC 5880
  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  *    |Vers |  Diag   |Sta|P|F|C|A|D|M|  Detect Mult  |    Length     |
  58  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  59  *    |                       My Discriminator                        |
  60  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  61  *    |                      Your Discriminator                       |
  62  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  63  *    |                    Desired Min TX Interval                    |
  64  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  65  *    |                   Required Min RX Interval                    |
  66  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  67  *    |                 Required Min Echo RX Interval                 |
  68  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  69  */
  70
  71 struct bfd_header_t {
  72     nd_uint8_t  version_diag;
  73     nd_uint8_t  flags;
  74     nd_uint8_t  detect_time_multiplier;
  75     nd_uint8_t  length;
  76     nd_uint32_t my_discriminator;
  77     nd_uint32_t your_discriminator;
  78     nd_uint32_t desired_min_tx_interval;
  79     nd_uint32_t required_min_rx_interval;
  80     nd_uint32_t required_min_echo_interval;
  81 };
  82
  83 /*
  84  *    An optional Authentication Header may be present
  85  *
  86  *     0                   1                   2                   3
  87  *     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
  88  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  89  *    |   Auth Type   |   Auth Len    |    Authentication Data...     |
  90  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  91  */
  92
  93 struct bfd_auth_header_t {
  94     nd_uint8_t auth_type;
  95     nd_uint8_t auth_len;
  96     nd_uint8_t auth_data;
  97     nd_uint8_t dummy; /* minimum 4 bytes */
  98 };
  99
 100 enum auth_type {
 101     AUTH_PASSWORD = 1,
 102     AUTH_MD5      = 2,
 103     AUTH_MET_MD5  = 3,
 104     AUTH_SHA1     = 4,
 105     AUTH_MET_SHA1 = 5
 106 };
 107
 108 static const struct tok bfd_v1_authentication_values[] = {
 109     { AUTH_PASSWORD, "Simple Password" },
 110     { AUTH_MD5,      "Keyed MD5" },
 111     { AUTH_MET_MD5,  "Meticulous Keyed MD5" },
 112     { AUTH_SHA1,     "Keyed SHA1" },
 113     { AUTH_MET_SHA1, "Meticulous Keyed SHA1" },
 114     { 0, NULL }
 115 };
 116
 117 enum auth_length {
 118     AUTH_PASSWORD_FIELD_MIN_LEN = 4,  /* header + password min: 3 + 1 */
 119     AUTH_PASSWORD_FIELD_MAX_LEN = 19, /* header + password max: 3 + 16 */
 120     AUTH_MD5_FIELD_LEN  = 24,
 121     AUTH_MD5_HASH_LEN   = 16,
 122     AUTH_SHA1_FIELD_LEN = 28,
 123     AUTH_SHA1_HASH_LEN  = 20
 124 };
 125
 126 #define BFD_EXTRACT_VERSION(x) (((x)&0xe0)>>5)
 127 #define BFD_EXTRACT_DIAG(x)     ((x)&0x1f)
 128
 129 static const struct tok bfd_port_values[] = {
 130     { BFD_CONTROL_PORT, "Control" },
 131     { BFD_ECHO_PORT,    "Echo" },
 132     { 0, NULL }
 133 };
 134
 135 static const struct tok bfd_diag_values[] = {
 136     { 0, "No Diagnostic" },
 137     { 1, "Control Detection Time Expired" },
 138     { 2, "Echo Function Failed" },
 139     { 3, "Neighbor Signaled Session Down" },
 140     { 4, "Forwarding Plane Reset" },
 141     { 5, "Path Down" },
 142     { 6, "Concatenated Path Down" },
 143     { 7, "Administratively Down" },
 144     { 8, "Reverse Concatenated Path Down" },
 145     { 0, NULL }
 146 };
 147
 148 static const struct tok bfd_v0_flag_values[] = {
 149     { 0x80, "I Hear You" },
 150     { 0x40, "Demand" },
 151     { 0x20, "Poll" },
 152     { 0x10, "Final" },
 153     { 0x08, "Reserved" },
 154     { 0x04, "Reserved" },
 155     { 0x02, "Reserved" },
 156     { 0x01, "Reserved" },
 157     { 0, NULL }
 158 };
 159
 160 #define BFD_FLAG_AUTH 0x04
 161
 162 static const struct tok bfd_v1_flag_values[] = {
 163     { 0x20, "Poll" },
 164     { 0x10, "Final" },
 165     { 0x08, "Control Plane Independent" },
 166     { BFD_FLAG_AUTH, "Authentication Present" },
 167     { 0x02, "Demand" },
 168     { 0x01, "Multipoint" },
 169     { 0, NULL }
 170 };
 171
 172 static const struct tok bfd_v1_state_values[] = {
 173     { 0, "AdminDown" },
 174     { 1, "Down" },
 175     { 2, "Init" },
 176     { 3, "Up" },
 177     { 0, NULL }
 178 };
 179
 180 static int
 181 auth_print(netdissect_options *ndo, const u_char *pptr)
 182 {
 183         const struct bfd_auth_header_t *bfd_auth_header;
 184         uint8_t auth_type, auth_len;
 185         int i;
 186
 187         pptr += sizeof (struct bfd_header_t);
 188         bfd_auth_header = (const struct bfd_auth_header_t *)pptr;
 189         ND_TCHECK_SIZE(bfd_auth_header);
 190         auth_type = EXTRACT_U_1(bfd_auth_header->auth_type);
 191         auth_len = EXTRACT_U_1(bfd_auth_header->auth_len);
 192         ND_PRINT("\n\tAuthentication: %s (%u), length: %u",
 193                  tok2str(bfd_v1_authentication_values,"Unknown",auth_type),
 194                  auth_type, auth_len);
 195                 pptr += 2;
 196                 ND_PRINT("\n\t  Auth Key ID: %u", EXTRACT_U_1(pptr));
 197
 198         switch(auth_type) {
 199             case AUTH_PASSWORD:
 200 /*
 201  *    Simple Password Authentication Section Format
 202  *
 203  *     0                   1                   2                   3
 204  *     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
 205  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 206  *    |   Auth Type   |   Auth Len    |  Auth Key ID  |  Password...  |
 207  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 208  *    |                              ...                              |
 209  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 210  */
 211                 if (auth_len < AUTH_PASSWORD_FIELD_MIN_LEN ||
 212                     auth_len > AUTH_PASSWORD_FIELD_MAX_LEN) {
 213                     ND_PRINT("[invalid length %u]",
 214                              auth_len);
 215                     break;
 216                 }
 217                 pptr++;
 218                 ND_PRINT(", Password: ");
 219                 /* the length is equal to the password length plus three */
 220                 if (nd_printn(ndo, pptr, auth_len - 3,
 221                               ndo->ndo_snapend))
 222                     goto trunc;
 223                 break;
 224             case AUTH_MD5:
 225             case AUTH_MET_MD5:
 226 /*
 227  *    Keyed MD5 and Meticulous Keyed MD5 Authentication Section Format
 228  *
 229  *     0                   1                   2                   3
 230  *     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
 231  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 232  *    |   Auth Type   |   Auth Len    |  Auth Key ID  |   Reserved    |
 233  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 234  *    |                        Sequence Number                        |
 235  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 236  *    |                      Auth Key/Digest...                       |
 237  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 238  *    |                              ...                              |
 239  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 240  */
 241                 if (auth_len != AUTH_MD5_FIELD_LEN) {
 242                     ND_PRINT("[invalid length %u]",
 243                              auth_len);
 244                     break;
 245                 }
 246                 pptr += 2;
 247                 ND_TCHECK_4(pptr);
 248                 ND_PRINT(", Sequence Number: 0x%08x", EXTRACT_BE_U_4(pptr));
 249                 pptr += 4;
 250                 ND_TCHECK_LEN(pptr, AUTH_MD5_HASH_LEN);
 251                 ND_PRINT("\n\t  Digest: ");
 252                 for(i = 0; i < AUTH_MD5_HASH_LEN; i++)
 253                     ND_PRINT("%02x", EXTRACT_U_1(pptr + i));
 254                 break;
 255             case AUTH_SHA1:
 256             case AUTH_MET_SHA1:
 257 /*
 258  *    Keyed SHA1 and Meticulous Keyed SHA1 Authentication Section Format
 259  *
 260  *     0                   1                   2                   3
 261  *     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
 262  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 263  *    |   Auth Type   |   Auth Len    |  Auth Key ID  |   Reserved    |
 264  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 265  *    |                        Sequence Number                        |
 266  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 267  *    |                       Auth Key/Hash...                        |
 268  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 269  *    |                              ...                              |
 270  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 271  */
 272                 if (auth_len != AUTH_SHA1_FIELD_LEN) {
 273                     ND_PRINT("[invalid length %u]",
 274                              auth_len);
 275                     break;
 276                 }
 277                 pptr += 2;
 278                 ND_TCHECK_4(pptr);
 279                 ND_PRINT(", Sequence Number: 0x%08x", EXTRACT_BE_U_4(pptr));
 280                 pptr += 4;
 281                 ND_TCHECK_LEN(pptr, AUTH_SHA1_HASH_LEN);
 282                 ND_PRINT("\n\t  Hash: ");
 283                 for(i = 0; i < AUTH_SHA1_HASH_LEN; i++)
 284                     ND_PRINT("%02x", EXTRACT_U_1(pptr + i));
 285                 break;
 286         }
 287         return 0;
 288
 289 trunc:
 290         return 1;
 291 }
 292
 293 void
 294 bfd_print(netdissect_options *ndo, const u_char *pptr,
 295           u_int len, u_int port)
 296 {
 297         const struct bfd_header_t *bfd_header;
 298         uint8_t version_diag;
 299         uint8_t version = 0;
 300         uint8_t flags;
 301
 302         ndo->ndo_protocol = "bfd";
 303         bfd_header = (const struct bfd_header_t *)pptr;
 304         version_diag = EXTRACT_U_1(bfd_header->version_diag);
 305         if (port == BFD_CONTROL_PORT) {
 306             ND_TCHECK_SIZE(bfd_header);
 307             version = BFD_EXTRACT_VERSION(version_diag);
 308         } else if (port == BFD_ECHO_PORT) {
 309             /* Echo is BFD v1 only */
 310             version = 1;
 311         }
 312         flags = EXTRACT_U_1(bfd_header->flags);
 313         switch ((port << 8) | version) {
 314
 315             /* BFDv0 */
 316         case (BFD_CONTROL_PORT << 8):
 317             if (ndo->ndo_vflag < 1)
 318             {
 319                 ND_PRINT("BFDv%u, %s, Flags: [%s], length: %u",
 320                        version,
 321                        tok2str(bfd_port_values, "unknown (%u)", port),
 322                        bittok2str(bfd_v0_flag_values, "none", flags),
 323                        len);
 324                 return;
 325             }
 326
 327             ND_PRINT("BFDv%u, length: %u\n\t%s, Flags: [%s], Diagnostic: %s (0x%02x)",
 328                    version,
 329                    len,
 330                    tok2str(bfd_port_values, "unknown (%u)", port),
 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                    EXTRACT_U_1(bfd_header->detect_time_multiplier),
 337                    EXTRACT_U_1(bfd_header->detect_time_multiplier) * EXTRACT_BE_U_4(bfd_header->desired_min_tx_interval)/1000,
 338                    EXTRACT_U_1(bfd_header->length));
 339
 340
 341             ND_PRINT("\n\tMy Discriminator: 0x%08x", EXTRACT_BE_U_4(bfd_header->my_discriminator));
 342             ND_PRINT(", Your Discriminator: 0x%08x", EXTRACT_BE_U_4(bfd_header->your_discriminator));
 343             ND_PRINT("\n\t  Desired min Tx Interval:    %4u ms", EXTRACT_BE_U_4(bfd_header->desired_min_tx_interval)/1000);
 344             ND_PRINT("\n\t  Required min Rx Interval:   %4u ms", EXTRACT_BE_U_4(bfd_header->required_min_rx_interval)/1000);
 345             ND_PRINT("\n\t  Required min Echo Interval: %4u ms", EXTRACT_BE_U_4(bfd_header->required_min_echo_interval)/1000);
 346             break;
 347
 348             /* BFDv1 */
 349         case (BFD_CONTROL_PORT << 8 | 1):
 350             if (ndo->ndo_vflag < 1)
 351             {
 352                 ND_PRINT("BFDv%u, %s, State %s, Flags: [%s], length: %u",
 353                        version,
 354                        tok2str(bfd_port_values, "unknown (%u)", port),
 355                        tok2str(bfd_v1_state_values, "unknown (%u)", (flags & 0xc0) >> 6),
 356                        bittok2str(bfd_v1_flag_values, "none", flags & 0x3f),
 357                        len);
 358                 return;
 359             }
 360
 361             ND_PRINT("BFDv%u, length: %u\n\t%s, State %s, Flags: [%s], Diagnostic: %s (0x%02x)",
 362                    version,
 363                    len,
 364                    tok2str(bfd_port_values, "unknown (%u)", port),
 365                    tok2str(bfd_v1_state_values, "unknown (%u)", (flags & 0xc0) >> 6),
 366                    bittok2str(bfd_v1_flag_values, "none", flags & 0x3f),
 367                    tok2str(bfd_diag_values,"unknown",BFD_EXTRACT_DIAG(version_diag)),
 368                    BFD_EXTRACT_DIAG(version_diag));
 369
 370             ND_PRINT("\n\tDetection Timer Multiplier: %u (%u ms Detection time), BFD Length: %u",
 371                    EXTRACT_U_1(bfd_header->detect_time_multiplier),
 372                    EXTRACT_U_1(bfd_header->detect_time_multiplier) * EXTRACT_BE_U_4(bfd_header->desired_min_tx_interval)/1000,
 373                    EXTRACT_U_1(bfd_header->length));
 374
 375
 376             ND_PRINT("\n\tMy Discriminator: 0x%08x", EXTRACT_BE_U_4(bfd_header->my_discriminator));
 377             ND_PRINT(", Your Discriminator: 0x%08x", EXTRACT_BE_U_4(bfd_header->your_discriminator));
 378             ND_PRINT("\n\t  Desired min Tx Interval:    %4u ms", EXTRACT_BE_U_4(bfd_header->desired_min_tx_interval)/1000);
 379             ND_PRINT("\n\t  Required min Rx Interval:   %4u ms", EXTRACT_BE_U_4(bfd_header->required_min_rx_interval)/1000);
 380             ND_PRINT("\n\t  Required min Echo Interval: %4u ms", EXTRACT_BE_U_4(bfd_header->required_min_echo_interval)/1000);
 381
 382             if (flags & BFD_FLAG_AUTH) {
 383                 if (auth_print(ndo, pptr))
 384                     goto trunc;
 385             }
 386             break;
 387
 388             /* BFDv0 */
 389         case (BFD_ECHO_PORT << 8): /* not yet supported - fall through */
 390             /* BFDv1 */
 391         case (BFD_ECHO_PORT << 8 | 1):
 392
 393         default:
 394             ND_PRINT("BFD, %s, length: %u",
 395                    tok2str(bfd_port_values, "unknown (%u)", port),
 396                    len);
 397             if (ndo->ndo_vflag >= 1) {
 398                     if(!print_unknown_data(ndo, pptr,"\n\t",len))
 399                             return;
 400             }
 401             break;
 402         }
 403         return;
 404
 405 trunc:
 406         nd_print_trunc(ndo);
 407 }