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     uint8_t version_diag;
  76     uint8_t flags;
  77     uint8_t detect_time_multiplier;
  78     uint8_t length;
  79     uint8_t my_discriminator[4];
  80     uint8_t your_discriminator[4];
  81     uint8_t desired_min_tx_interval[4];
  82     uint8_t required_min_rx_interval[4];
  83     uint8_t required_min_echo_interval[4];
  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     uint8_t auth_type;
  98     uint8_t auth_len;
  99     uint8_t auth_data;
 100     uint8_t dummy; /* minimun 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, register const u_char *pptr)
 179 {
 180         const struct bfd_auth_header_t *bfd_auth_header;
 181         int i;
 182
 183         pptr += sizeof (const struct bfd_header_t);
 184         bfd_auth_header = (const struct bfd_auth_header_t *)pptr;
 185         ND_TCHECK(*bfd_auth_header);
 186         ND_PRINT((ndo, "\n\tAuthentication: %s (%u), length: %u",
 187                  tok2str(bfd_v1_authentication_values,"Unknown",bfd_auth_header->auth_type),
 188                  bfd_auth_header->auth_type,
 189                  bfd_auth_header->auth_len));
 190                 pptr += 2;
 191                 ND_PRINT((ndo, "\n\t  Auth Key ID: %d", *pptr));
 192
 193         switch(bfd_auth_header->auth_type) {
 194             case AUTH_PASSWORD:
 195 /*
 196  *    Simple Password Authentication Section Format
 197  *
 198  *     0                   1                   2                   3
 199  *     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
 200  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 201  *    |   Auth Type   |   Auth Len    |  Auth Key ID  |  Password...  |
 202  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 203  *    |                              ...                              |
 204  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 205  */
 206                 if (bfd_auth_header->auth_len < AUTH_PASSWORD_FIELD_MIN_LEN ||
 207                     bfd_auth_header->auth_len > AUTH_PASSWORD_FIELD_MAX_LEN) {
 208                     ND_PRINT((ndo, "[invalid length %d]",
 209                              bfd_auth_header->auth_len));
 210                     break;
 211                 }
 212                 pptr++;
 213                 ND_PRINT((ndo, ", Password: "));
 214                 /* the length is equal to the password length plus three */
 215                 if (fn_printn(ndo, pptr, bfd_auth_header->auth_len - 3,
 216                               ndo->ndo_snapend))
 217                     goto trunc;
 218                 break;
 219             case AUTH_MD5:
 220             case AUTH_MET_MD5:
 221 /*
 222  *    Keyed MD5 and Meticulous Keyed MD5 Authentication Section Format
 223  *
 224  *     0                   1                   2                   3
 225  *     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
 226  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 227  *    |   Auth Type   |   Auth Len    |  Auth Key ID  |   Reserved    |
 228  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 229  *    |                        Sequence Number                        |
 230  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 231  *    |                      Auth Key/Digest...                       |
 232  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 233  *    |                              ...                              |
 234  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 235  */
 236                 if (bfd_auth_header->auth_len != AUTH_MD5_FIELD_LEN) {
 237                     ND_PRINT((ndo, "[invalid length %d]",
 238                              bfd_auth_header->auth_len));
 239                     break;
 240                 }
 241                 pptr += 2;
 242                 ND_TCHECK2(*pptr, 4);
 243                 ND_PRINT((ndo, ", Sequence Number: 0x%08x", EXTRACT_32BITS(pptr)));
 244                 pptr += 4;
 245                 ND_TCHECK2(*pptr, AUTH_MD5_HASH_LEN);
 246                 ND_PRINT((ndo, "\n\t  Digest: "));
 247                 for(i = 0; i < AUTH_MD5_HASH_LEN; i++)
 248                     ND_PRINT((ndo, "%02x", pptr[i]));
 249                 break;
 250             case AUTH_SHA1:
 251             case AUTH_MET_SHA1:
 252 /*
 253  *    Keyed SHA1 and Meticulous Keyed SHA1 Authentication Section Format
 254  *
 255  *     0                   1                   2                   3
 256  *     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
 257  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 258  *    |   Auth Type   |   Auth Len    |  Auth Key ID  |   Reserved    |
 259  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 260  *    |                        Sequence Number                        |
 261  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 262  *    |                       Auth Key/Hash...                        |
 263  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 264  *    |                              ...                              |
 265  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 266  */
 267                 if (bfd_auth_header->auth_len != AUTH_SHA1_FIELD_LEN) {
 268                     ND_PRINT((ndo, "[invalid length %d]",
 269                              bfd_auth_header->auth_len));
 270                     break;
 271                 }
 272                 pptr += 2;
 273                 ND_TCHECK2(*pptr, 4);
 274                 ND_PRINT((ndo, ", Sequence Number: 0x%08x", EXTRACT_32BITS(pptr)));
 275                 pptr += 4;
 276                 ND_TCHECK2(*pptr, AUTH_SHA1_HASH_LEN);
 277                 ND_PRINT((ndo, "\n\t  Hash: "));
 278                 for(i = 0; i < AUTH_SHA1_HASH_LEN; i++)
 279                     ND_PRINT((ndo, "%02x", pptr[i]));
 280                 break;
 281         }
 282         return 0;
 283
 284 trunc:
 285         return 1;
 286 }
 287
 288 void
 289 bfd_print(netdissect_options *ndo, register const u_char *pptr,
 290           register u_int len, register u_int port)
 291 {
 292         if (port == BFD_CONTROL_PORT) {
 293             /*
 294              * Control packet.
 295              */
 296             const struct bfd_header_t *bfd_header;
 297             uint8_t version_diag;
 298             uint8_t version = 0;
 299             uint8_t flags;
 300
 301             bfd_header = (const struct bfd_header_t *)pptr;
 302             ND_TCHECK(*bfd_header);
 303             version_diag = bfd_header->version_diag;
 304             version = BFD_EXTRACT_VERSION(version_diag);
 305             flags = bfd_header->flags;
 306
 307             switch (version) {
 308
 309                 /* BFDv0 */
 310             case 0:
 311                 if (ndo->ndo_vflag < 1)
 312                 {
 313                     ND_PRINT((ndo, "BFDv0, Control, Flags: [%s], length: %u",
 314                            bittok2str(bfd_v0_flag_values, "none", flags),
 315                            len));
 316                     return;
 317                 }
 318
 319                 ND_PRINT((ndo, "BFDv0, length: %u\n\tControl, Flags: [%s], Diagnostic: %s (0x%02x)",
 320                        len,
 321                        bittok2str(bfd_v0_flag_values, "none", flags),
 322                        tok2str(bfd_diag_values,"unknown",BFD_EXTRACT_DIAG(version_diag)),
 323                        BFD_EXTRACT_DIAG(version_diag)));
 324
 325                 ND_PRINT((ndo, "\n\tDetection Timer Multiplier: %u (%u ms Detection time), BFD Length: %u",
 326                        bfd_header->detect_time_multiplier,
 327                        bfd_header->detect_time_multiplier * EXTRACT_32BITS(bfd_header->desired_min_tx_interval)/1000,
 328                        bfd_header->length));
 329
 330
 331                 ND_PRINT((ndo, "\n\tMy Discriminator: 0x%08x", EXTRACT_32BITS(bfd_header->my_discriminator)));
 332                 ND_PRINT((ndo, ", Your Discriminator: 0x%08x", EXTRACT_32BITS(bfd_header->your_discriminator)));
 333                 ND_PRINT((ndo, "\n\t  Desired min Tx Interval:    %4u ms", EXTRACT_32BITS(bfd_header->desired_min_tx_interval)/1000));
 334                 ND_PRINT((ndo, "\n\t  Required min Rx Interval:   %4u ms", EXTRACT_32BITS(bfd_header->required_min_rx_interval)/1000));
 335                 ND_PRINT((ndo, "\n\t  Required min Echo Interval: %4u ms", EXTRACT_32BITS(bfd_header->required_min_echo_interval)/1000));
 336
 337                 if (flags & BFD_FLAG_AUTH) {
 338                     if (auth_print(ndo, pptr))
 339                         goto trunc;
 340                 }
 341                 break;
 342
 343                 /* BFDv1 */
 344             case 1:
 345                 if (ndo->ndo_vflag < 1)
 346                 {
 347                     ND_PRINT((ndo, "BFDv1, Control, State %s, Flags: [%s], length: %u",
 348                            tok2str(bfd_v1_state_values, "unknown (%u)", (flags & 0xc0) >> 6),
 349                            bittok2str(bfd_v1_flag_values, "none", flags & 0x3f),
 350                            len));
 351                     return;
 352                 }
 353
 354                 ND_PRINT((ndo, "BFDv1, length: %u\n\tControl, State %s, Flags: [%s], Diagnostic: %s (0x%02x)",
 355                        len,
 356                        tok2str(bfd_v1_state_values, "unknown (%u)", (flags & 0xc0) >> 6),
 357                        bittok2str(bfd_v1_flag_values, "none", flags & 0x3f),
 358                        tok2str(bfd_diag_values,"unknown",BFD_EXTRACT_DIAG(version_diag)),
 359                        BFD_EXTRACT_DIAG(version_diag)));
 360
 361                 ND_PRINT((ndo, "\n\tDetection Timer Multiplier: %u (%u ms Detection time), BFD Length: %u",
 362                        bfd_header->detect_time_multiplier,
 363                        bfd_header->detect_time_multiplier * EXTRACT_32BITS(bfd_header->desired_min_tx_interval)/1000,
 364                        bfd_header->length));
 365
 366
 367                 ND_PRINT((ndo, "\n\tMy Discriminator: 0x%08x", EXTRACT_32BITS(bfd_header->my_discriminator)));
 368                 ND_PRINT((ndo, ", Your Discriminator: 0x%08x", EXTRACT_32BITS(bfd_header->your_discriminator)));
 369                 ND_PRINT((ndo, "\n\t  Desired min Tx Interval:    %4u ms", EXTRACT_32BITS(bfd_header->desired_min_tx_interval)/1000));
 370                 ND_PRINT((ndo, "\n\t  Required min Rx Interval:   %4u ms", EXTRACT_32BITS(bfd_header->required_min_rx_interval)/1000));
 371                 ND_PRINT((ndo, "\n\t  Required min Echo Interval: %4u ms", EXTRACT_32BITS(bfd_header->required_min_echo_interval)/1000));
 372
 373                 if (flags & BFD_FLAG_AUTH) {
 374                     if (auth_print(ndo, pptr))
 375                         goto trunc;
 376                 }
 377                 break;
 378
 379             default:
 380                 ND_PRINT((ndo, "BFDv%u, Control, length: %u",
 381                        version,
 382                        len));
 383                 if (ndo->ndo_vflag >= 1) {
 384                     if(!print_unknown_data(ndo, pptr,"\n\t",len))
 385                         return;
 386                 }
 387                 break;
 388             }
 389         } else if (port == BFD_ECHO_PORT) {
 390             /*
 391              * Echo packet.
 392              */
 393             ND_PRINT((ndo, "BFD, Echo, length: %u",
 394                    len));
 395             if (ndo->ndo_vflag >= 1) {
 396                 if(!print_unknown_data(ndo, pptr,"\n\t",len))
 397                     return;
 398             }
 399         } else {
 400             /*
 401              * Unknown packet type.
 402              */
 403             ND_PRINT((ndo, "BFD, unknown (%u), length: %u",
 404                    port,
 405                    len));
 406             if (ndo->ndo_vflag >= 1) {
 407                     if(!print_unknown_data(ndo, pptr,"\n\t",len))
 408                             return;
 409             }
 410         }
 411         return;
 412
 413 trunc:
 414         ND_PRINT((ndo, "[|BFD]"));
 415 }
 416 /*
 417  * Local Variables:
 418  * c-style: whitesmith
 419  * c-basic-offset: 8
 420  * End:
 421  */