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 #define BFD_FLAG_AUTH 0x04
 146
 147 static const struct tok bfd_v0_flag_values[] = {
 148     { 0x80, "I Hear You" },
 149     { 0x40, "Demand" },
 150     { 0x20, "Poll" },
 151     { 0x10, "Final" },
 152     { 0x08, "Control Plane Independent" },
 153     { BFD_FLAG_AUTH, "Authentication Present" },
 154     { 0x02, "Reserved" },
 155     { 0x01, "Reserved" },
 156     { 0, NULL }
 157 };
 158
 159 static const struct tok bfd_v1_flag_values[] = {
 160     { 0x20, "Poll" },
 161     { 0x10, "Final" },
 162     { 0x08, "Control Plane Independent" },
 163     { BFD_FLAG_AUTH, "Authentication Present" },
 164     { 0x02, "Demand" },
 165     { 0x01, "Multipoint" },
 166     { 0, NULL }
 167 };
 168
 169 static const struct tok bfd_v1_state_values[] = {
 170     { 0, "AdminDown" },
 171     { 1, "Down" },
 172     { 2, "Init" },
 173     { 3, "Up" },
 174     { 0, NULL }
 175 };
 176
 177 static int
 178 auth_print(netdissect_options *ndo, const u_char *pptr)
 179 {
 180         const struct bfd_auth_header_t *bfd_auth_header;
 181         uint8_t auth_type, auth_len;
 182         int i;
 183
 184         pptr += sizeof (struct bfd_header_t);
 185         bfd_auth_header = (const struct bfd_auth_header_t *)pptr;
 186         ND_TCHECK_SIZE(bfd_auth_header);
 187         auth_type = EXTRACT_U_1(bfd_auth_header->auth_type);
 188         auth_len = EXTRACT_U_1(bfd_auth_header->auth_len);
 189         ND_PRINT("\n\tAuthentication: %s (%u), length: %u",
 190                  tok2str(bfd_v1_authentication_values,"Unknown",auth_type),
 191                  auth_type, auth_len);
 192                 pptr += 2;
 193                 ND_PRINT("\n\t  Auth Key ID: %u", EXTRACT_U_1(pptr));
 194
 195         switch(auth_type) {
 196             case AUTH_PASSWORD:
 197 /*
 198  *    Simple Password Authentication Section Format
 199  *
 200  *     0                   1                   2                   3
 201  *     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
 202  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 203  *    |   Auth Type   |   Auth Len    |  Auth Key ID  |  Password...  |
 204  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 205  *    |                              ...                              |
 206  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 207  */
 208                 if (auth_len < AUTH_PASSWORD_FIELD_MIN_LEN ||
 209                     auth_len > AUTH_PASSWORD_FIELD_MAX_LEN) {
 210                     ND_PRINT("[invalid length %u]",
 211                              auth_len);
 212                     break;
 213                 }
 214                 pptr++;
 215                 ND_PRINT(", Password: ");
 216                 /* the length is equal to the password length plus three */
 217                 if (nd_printn(ndo, pptr, auth_len - 3,
 218                               ndo->ndo_snapend))
 219                     goto trunc;
 220                 break;
 221             case AUTH_MD5:
 222             case AUTH_MET_MD5:
 223 /*
 224  *    Keyed MD5 and Meticulous Keyed MD5 Authentication Section Format
 225  *
 226  *     0                   1                   2                   3
 227  *     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
 228  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 229  *    |   Auth Type   |   Auth Len    |  Auth Key ID  |   Reserved    |
 230  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 231  *    |                        Sequence Number                        |
 232  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 233  *    |                      Auth Key/Digest...                       |
 234  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 235  *    |                              ...                              |
 236  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 237  */
 238                 if (auth_len != AUTH_MD5_FIELD_LEN) {
 239                     ND_PRINT("[invalid length %u]",
 240                              auth_len);
 241                     break;
 242                 }
 243                 pptr += 2;
 244                 ND_TCHECK_4(pptr);
 245                 ND_PRINT(", Sequence Number: 0x%08x", EXTRACT_BE_U_4(pptr));
 246                 pptr += 4;
 247                 ND_TCHECK_LEN(pptr, AUTH_MD5_HASH_LEN);
 248                 ND_PRINT("\n\t  Digest: ");
 249                 for(i = 0; i < AUTH_MD5_HASH_LEN; i++)
 250                     ND_PRINT("%02x", EXTRACT_U_1(pptr + i));
 251                 break;
 252             case AUTH_SHA1:
 253             case AUTH_MET_SHA1:
 254 /*
 255  *    Keyed SHA1 and Meticulous Keyed SHA1 Authentication Section Format
 256  *
 257  *     0                   1                   2                   3
 258  *     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
 259  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 260  *    |   Auth Type   |   Auth Len    |  Auth Key ID  |   Reserved    |
 261  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 262  *    |                        Sequence Number                        |
 263  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 264  *    |                       Auth Key/Hash...                        |
 265  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 266  *    |                              ...                              |
 267  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 268  */
 269                 if (auth_len != AUTH_SHA1_FIELD_LEN) {
 270                     ND_PRINT("[invalid length %u]",
 271                              auth_len);
 272                     break;
 273                 }
 274                 pptr += 2;
 275                 ND_TCHECK_4(pptr);
 276                 ND_PRINT(", Sequence Number: 0x%08x", EXTRACT_BE_U_4(pptr));
 277                 pptr += 4;
 278                 ND_TCHECK_LEN(pptr, AUTH_SHA1_HASH_LEN);
 279                 ND_PRINT("\n\t  Hash: ");
 280                 for(i = 0; i < AUTH_SHA1_HASH_LEN; i++)
 281                     ND_PRINT("%02x", EXTRACT_U_1(pptr + i));
 282                 break;
 283         }
 284         return 0;
 285
 286 trunc:
 287         return 1;
 288 }
 289
 290 void
 291 bfd_print(netdissect_options *ndo, const u_char *pptr,
 292           u_int len, u_int port)
 293 {
 294         ndo->ndo_protocol = "bfd";
 295         if (port == BFD_CONTROL_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 = EXTRACT_U_1(bfd_header->version_diag);
 307             version = BFD_EXTRACT_VERSION(version_diag);
 308             flags = EXTRACT_U_1(bfd_header->flags);
 309
 310             switch (version) {
 311
 312                 /* BFDv0 */
 313             case 0:
 314                 if (ndo->ndo_vflag < 1)
 315                 {
 316                     ND_PRINT("BFDv0, Control, Flags: [%s], length: %u",
 317                            bittok2str(bfd_v0_flag_values, "none", flags),
 318                            len);
 319                     return;
 320                 }
 321
 322                 ND_PRINT("BFDv0, length: %u\n\tControl, Flags: [%s], Diagnostic: %s (0x%02x)",
 323                        len,
 324                        bittok2str(bfd_v0_flag_values, "none", flags),
 325                        tok2str(bfd_diag_values,"unknown",BFD_EXTRACT_DIAG(version_diag)),
 326                        BFD_EXTRACT_DIAG(version_diag));
 327
 328                 ND_PRINT("\n\tDetection Timer Multiplier: %u (%u ms Detection time), BFD Length: %u",
 329                        EXTRACT_U_1(bfd_header->detect_time_multiplier),
 330                        EXTRACT_U_1(bfd_header->detect_time_multiplier) * EXTRACT_BE_U_4(bfd_header->desired_min_tx_interval)/1000,
 331                        EXTRACT_U_1(bfd_header->length));
 332
 333
 334                 ND_PRINT("\n\tMy Discriminator: 0x%08x", EXTRACT_BE_U_4(bfd_header->my_discriminator));
 335                 ND_PRINT(", Your Discriminator: 0x%08x", EXTRACT_BE_U_4(bfd_header->your_discriminator));
 336                 ND_PRINT("\n\t  Desired min Tx Interval:    %4u ms", EXTRACT_BE_U_4(bfd_header->desired_min_tx_interval)/1000);
 337                 ND_PRINT("\n\t  Required min Rx Interval:   %4u ms", EXTRACT_BE_U_4(bfd_header->required_min_rx_interval)/1000);
 338                 ND_PRINT("\n\t  Required min Echo Interval: %4u ms", EXTRACT_BE_U_4(bfd_header->required_min_echo_interval)/1000);
 339
 340                 if (flags & BFD_FLAG_AUTH) {
 341                     if (auth_print(ndo, pptr))
 342                         goto trunc;
 343                 }
 344                 break;
 345
 346                 /* BFDv1 */
 347             case 1:
 348                 if (ndo->ndo_vflag < 1)
 349                 {
 350                     ND_PRINT("BFDv1, Control, State %s, Flags: [%s], length: %u",
 351                            tok2str(bfd_v1_state_values, "unknown (%u)", (flags & 0xc0) >> 6),
 352                            bittok2str(bfd_v1_flag_values, "none", flags & 0x3f),
 353                            len);
 354                     return;
 355                 }
 356
 357                 ND_PRINT("BFDv1, length: %u\n\tControl, State %s, Flags: [%s], Diagnostic: %s (0x%02x)",
 358                        len,
 359                        tok2str(bfd_v1_state_values, "unknown (%u)", (flags & 0xc0) >> 6),
 360                        bittok2str(bfd_v1_flag_values, "none", flags & 0x3f),
 361                        tok2str(bfd_diag_values,"unknown",BFD_EXTRACT_DIAG(version_diag)),
 362                        BFD_EXTRACT_DIAG(version_diag));
 363
 364                 ND_PRINT("\n\tDetection Timer Multiplier: %u (%u ms Detection time), BFD Length: %u",
 365                        EXTRACT_U_1(bfd_header->detect_time_multiplier),
 366                        EXTRACT_U_1(bfd_header->detect_time_multiplier) * EXTRACT_BE_U_4(bfd_header->desired_min_tx_interval)/1000,
 367                        EXTRACT_U_1(bfd_header->length));
 368
 369
 370                 ND_PRINT("\n\tMy Discriminator: 0x%08x", EXTRACT_BE_U_4(bfd_header->my_discriminator));
 371                 ND_PRINT(", Your Discriminator: 0x%08x", EXTRACT_BE_U_4(bfd_header->your_discriminator));
 372                 ND_PRINT("\n\t  Desired min Tx Interval:    %4u ms", EXTRACT_BE_U_4(bfd_header->desired_min_tx_interval)/1000);
 373                 ND_PRINT("\n\t  Required min Rx Interval:   %4u ms", EXTRACT_BE_U_4(bfd_header->required_min_rx_interval)/1000);
 374                 ND_PRINT("\n\t  Required min Echo Interval: %4u ms", EXTRACT_BE_U_4(bfd_header->required_min_echo_interval)/1000);
 375
 376                 if (flags & BFD_FLAG_AUTH) {
 377                     if (auth_print(ndo, pptr))
 378                         goto trunc;
 379                 }
 380                 break;
 381
 382             default:
 383                 ND_PRINT("BFDv%u, Control, length: %u",
 384                        version,
 385                        len);
 386                 if (ndo->ndo_vflag >= 1) {
 387                     if(!print_unknown_data(ndo, pptr,"\n\t",len))
 388                         return;
 389                 }
 390                 break;
 391             }
 392         } else if (port == BFD_ECHO_PORT) {
 393             /*
 394              * Echo packet.
 395              */
 396             ND_PRINT("BFD, Echo, length: %u",
 397                    len);
 398             if (ndo->ndo_vflag >= 1) {
 399                 if(!print_unknown_data(ndo, pptr,"\n\t",len))
 400                     return;
 401             }
 402         } else {
 403             /*
 404              * Unknown packet type.
 405              */
 406             ND_PRINT("BFD, unknown (%u), length: %u",
 407                    port,
 408                    len);
 409             if (ndo->ndo_vflag >= 1) {
 410                     if(!print_unknown_data(ndo, pptr,"\n\t",len))
 411                             return;
 412             }
 413         }
 414         return;
 415
 416 trunc:
 417         nd_print_trunc(ndo);
 418 }