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     uint8_t version_diag;
  73     uint8_t flags;
  74     uint8_t detect_time_multiplier;
  75     uint8_t length;
  76     uint8_t my_discriminator[4];
  77     uint8_t your_discriminator[4];
  78     uint8_t desired_min_tx_interval[4];
  79     uint8_t required_min_rx_interval[4];
  80     uint8_t required_min_echo_interval[4];
  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     uint8_t auth_type;
  95     uint8_t auth_len;
  96     uint8_t auth_data;
  97     uint8_t dummy; /* minimun 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, register const u_char *pptr)
 182 {
 183         const struct bfd_auth_header_t *bfd_auth_header;
 184         int i;
 185
 186         pptr += sizeof (struct bfd_header_t);
 187         bfd_auth_header = (const struct bfd_auth_header_t *)pptr;
 188         ND_TCHECK(*bfd_auth_header);
 189         ND_PRINT((ndo, "\n\tAuthentication: %s (%u), length: %u",
 190                  tok2str(bfd_v1_authentication_values,"Unknown",bfd_auth_header->auth_type),
 191                  bfd_auth_header->auth_type,
 192                  bfd_auth_header->auth_len));
 193                 pptr += 2;
 194                 ND_PRINT((ndo, "\n\t  Auth Key ID: %d", *pptr));
 195
 196         switch(bfd_auth_header->auth_type) {
 197             case AUTH_PASSWORD:
 198 /*
 199  *    Simple Password Authentication Section Format
 200  *
 201  *     0                   1                   2                   3
 202  *     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
 203  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 204  *    |   Auth Type   |   Auth Len    |  Auth Key ID  |  Password...  |
 205  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 206  *    |                              ...                              |
 207  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 208  */
 209                 if (bfd_auth_header->auth_len < AUTH_PASSWORD_FIELD_MIN_LEN ||
 210                     bfd_auth_header->auth_len > AUTH_PASSWORD_FIELD_MAX_LEN) {
 211                     ND_PRINT((ndo, "[invalid length %d]",
 212                              bfd_auth_header->auth_len));
 213                     break;
 214                 }
 215                 pptr++;
 216                 ND_PRINT((ndo, ", Password: "));
 217                 /* the length is equal to the password length plus three */
 218                 if (fn_printn(ndo, pptr, bfd_auth_header->auth_len - 3,
 219                               ndo->ndo_snapend))
 220                     goto trunc;
 221                 break;
 222             case AUTH_MD5:
 223             case AUTH_MET_MD5:
 224 /*
 225  *    Keyed MD5 and Meticulous Keyed MD5 Authentication Section Format
 226  *
 227  *     0                   1                   2                   3
 228  *     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
 229  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 230  *    |   Auth Type   |   Auth Len    |  Auth Key ID  |   Reserved    |
 231  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 232  *    |                        Sequence Number                        |
 233  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 234  *    |                      Auth Key/Digest...                       |
 235  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 236  *    |                              ...                              |
 237  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 238  */
 239                 if (bfd_auth_header->auth_len != AUTH_MD5_FIELD_LEN) {
 240                     ND_PRINT((ndo, "[invalid length %d]",
 241                              bfd_auth_header->auth_len));
 242                     break;
 243                 }
 244                 pptr += 2;
 245                 ND_TCHECK2(*pptr, 4);
 246                 ND_PRINT((ndo, ", Sequence Number: 0x%08x", EXTRACT_BE_U_4(pptr)));
 247                 pptr += 4;
 248                 ND_TCHECK2(*pptr, AUTH_MD5_HASH_LEN);
 249                 ND_PRINT((ndo, "\n\t  Digest: "));
 250                 for(i = 0; i < AUTH_MD5_HASH_LEN; i++)
 251                     ND_PRINT((ndo, "%02x", pptr[i]));
 252                 break;
 253             case AUTH_SHA1:
 254             case AUTH_MET_SHA1:
 255 /*
 256  *    Keyed SHA1 and Meticulous Keyed SHA1 Authentication Section Format
 257  *
 258  *     0                   1                   2                   3
 259  *     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
 260  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 261  *    |   Auth Type   |   Auth Len    |  Auth Key ID  |   Reserved    |
 262  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 263  *    |                        Sequence Number                        |
 264  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 265  *    |                       Auth Key/Hash...                        |
 266  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 267  *    |                              ...                              |
 268  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 269  */
 270                 if (bfd_auth_header->auth_len != AUTH_SHA1_FIELD_LEN) {
 271                     ND_PRINT((ndo, "[invalid length %d]",
 272                              bfd_auth_header->auth_len));
 273                     break;
 274                 }
 275                 pptr += 2;
 276                 ND_TCHECK2(*pptr, 4);
 277                 ND_PRINT((ndo, ", Sequence Number: 0x%08x", EXTRACT_BE_U_4(pptr)));
 278                 pptr += 4;
 279                 ND_TCHECK2(*pptr, AUTH_SHA1_HASH_LEN);
 280                 ND_PRINT((ndo, "\n\t  Hash: "));
 281                 for(i = 0; i < AUTH_SHA1_HASH_LEN; i++)
 282                     ND_PRINT((ndo, "%02x", pptr[i]));
 283                 break;
 284         }
 285         return 0;
 286
 287 trunc:
 288         return 1;
 289 }
 290
 291 void
 292 bfd_print(netdissect_options *ndo, register const u_char *pptr,
 293           register u_int len, register u_int port)
 294 {
 295         const struct bfd_header_t *bfd_header;
 296         uint8_t version = 0;
 297
 298         bfd_header = (const struct bfd_header_t *)pptr;
 299         if (port == BFD_CONTROL_PORT) {
 300             ND_TCHECK(*bfd_header);
 301             version = BFD_EXTRACT_VERSION(bfd_header->version_diag);
 302         } else if (port == BFD_ECHO_PORT) {
 303             /* Echo is BFD v1 only */
 304             version = 1;
 305         }
 306         switch ((port << 8) | version) {
 307
 308             /* BFDv0 */
 309         case (BFD_CONTROL_PORT << 8):
 310             if (ndo->ndo_vflag < 1)
 311             {
 312                 ND_PRINT((ndo, "BFDv%u, %s, Flags: [%s], length: %u",
 313                        version,
 314                        tok2str(bfd_port_values, "unknown (%u)", port),
 315                        bittok2str(bfd_v0_flag_values, "none", bfd_header->flags),
 316                        len));
 317                 return;
 318             }
 319
 320             ND_PRINT((ndo, "BFDv%u, length: %u\n\t%s, Flags: [%s], Diagnostic: %s (0x%02x)",
 321                    version,
 322                    len,
 323                    tok2str(bfd_port_values, "unknown (%u)", port),
 324                    bittok2str(bfd_v0_flag_values, "none", bfd_header->flags),
 325                    tok2str(bfd_diag_values,"unknown",BFD_EXTRACT_DIAG(bfd_header->version_diag)),
 326                    BFD_EXTRACT_DIAG(bfd_header->version_diag)));
 327
 328             ND_PRINT((ndo, "\n\tDetection Timer Multiplier: %u (%u ms Detection time), BFD Length: %u",
 329                    bfd_header->detect_time_multiplier,
 330                    bfd_header->detect_time_multiplier * EXTRACT_BE_U_4(bfd_header->desired_min_tx_interval)/1000,
 331                    bfd_header->length));
 332
 333
 334             ND_PRINT((ndo, "\n\tMy Discriminator: 0x%08x", EXTRACT_BE_U_4(bfd_header->my_discriminator)));
 335             ND_PRINT((ndo, ", Your Discriminator: 0x%08x", EXTRACT_BE_U_4(bfd_header->your_discriminator)));
 336             ND_PRINT((ndo, "\n\t  Desired min Tx Interval:    %4u ms", EXTRACT_BE_U_4(bfd_header->desired_min_tx_interval)/1000));
 337             ND_PRINT((ndo, "\n\t  Required min Rx Interval:   %4u ms", EXTRACT_BE_U_4(bfd_header->required_min_rx_interval)/1000));
 338             ND_PRINT((ndo, "\n\t  Required min Echo Interval: %4u ms", EXTRACT_BE_U_4(bfd_header->required_min_echo_interval)/1000));
 339             break;
 340
 341             /* BFDv1 */
 342         case (BFD_CONTROL_PORT << 8 | 1):
 343             if (ndo->ndo_vflag < 1)
 344             {
 345                 ND_PRINT((ndo, "BFDv%u, %s, State %s, Flags: [%s], length: %u",
 346                        version,
 347                        tok2str(bfd_port_values, "unknown (%u)", port),
 348                        tok2str(bfd_v1_state_values, "unknown (%u)", (bfd_header->flags & 0xc0) >> 6),
 349                        bittok2str(bfd_v1_flag_values, "none", bfd_header->flags & 0x3f),
 350                        len));
 351                 return;
 352             }
 353
 354             ND_PRINT((ndo, "BFDv%u, length: %u\n\t%s, State %s, Flags: [%s], Diagnostic: %s (0x%02x)",
 355                    version,
 356                    len,
 357                    tok2str(bfd_port_values, "unknown (%u)", port),
 358                    tok2str(bfd_v1_state_values, "unknown (%u)", (bfd_header->flags & 0xc0) >> 6),
 359                    bittok2str(bfd_v1_flag_values, "none", bfd_header->flags & 0x3f),
 360                    tok2str(bfd_diag_values,"unknown",BFD_EXTRACT_DIAG(bfd_header->version_diag)),
 361                    BFD_EXTRACT_DIAG(bfd_header->version_diag)));
 362
 363             ND_PRINT((ndo, "\n\tDetection Timer Multiplier: %u (%u ms Detection time), BFD Length: %u",
 364                    bfd_header->detect_time_multiplier,
 365                    bfd_header->detect_time_multiplier * EXTRACT_BE_U_4(bfd_header->desired_min_tx_interval)/1000,
 366                    bfd_header->length));
 367
 368
 369             ND_PRINT((ndo, "\n\tMy Discriminator: 0x%08x", EXTRACT_BE_U_4(bfd_header->my_discriminator)));
 370             ND_PRINT((ndo, ", Your Discriminator: 0x%08x", EXTRACT_BE_U_4(bfd_header->your_discriminator)));
 371             ND_PRINT((ndo, "\n\t  Desired min Tx Interval:    %4u ms", EXTRACT_BE_U_4(bfd_header->desired_min_tx_interval)/1000));
 372             ND_PRINT((ndo, "\n\t  Required min Rx Interval:   %4u ms", EXTRACT_BE_U_4(bfd_header->required_min_rx_interval)/1000));
 373             ND_PRINT((ndo, "\n\t  Required min Echo Interval: %4u ms", EXTRACT_BE_U_4(bfd_header->required_min_echo_interval)/1000));
 374
 375             if (bfd_header->flags & BFD_FLAG_AUTH) {
 376                 if (auth_print(ndo, pptr))
 377                     goto trunc;
 378             }
 379             break;
 380
 381             /* BFDv0 */
 382         case (BFD_ECHO_PORT << 8): /* not yet supported - fall through */
 383             /* BFDv1 */
 384         case (BFD_ECHO_PORT << 8 | 1):
 385
 386         default:
 387             ND_PRINT((ndo, "BFD, %s, length: %u",
 388                    tok2str(bfd_port_values, "unknown (%u)", port),
 389                    len));
 390             if (ndo->ndo_vflag >= 1) {
 391                     if(!print_unknown_data(ndo, pptr,"\n\t",len))
 392                             return;
 393             }
 394             break;
 395         }
 396         return;
 397
 398 trunc:
 399         ND_PRINT((ndo, "[|BFD]"));
 400 }
 401 /*
 402  * Local Variables:
 403  * c-style: whitesmith
 404  * c-basic-offset: 8
 405  * End:
 406  */