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