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 #define ND_LONGJMP_FROM_TCHECK
  30 #include "netdissect.h"
  31 #include "extract.h"
  32
  33 #include "udp.h"
  34
  35 /*
  36  * Control packet, BFDv0, draft-ietf-bfd-base-01
  37  *
  38  *     0                   1                   2                   3
  39  *     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
  40  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  41  *    |Vers |  Diag   |H|D|P|F|C|A|Rsv|  Detect Mult  |    Length     |
  42  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  43  *    |                       My Discriminator                        |
  44  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  45  *    |                      Your Discriminator                       |
  46  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  47  *    |                    Desired Min TX Interval                    |
  48  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  49  *    |                   Required Min RX Interval                    |
  50  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  51  *    |                 Required Min Echo RX Interval                 |
  52  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  53  */
  54
  55 /*
  56  *  Control packet, BFDv1, RFC 5880
  57  *
  58  *     0                   1                   2                   3
  59  *     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
  60  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  61  *    |Vers |  Diag   |Sta|P|F|C|A|D|M|  Detect Mult  |    Length     |
  62  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  63  *    |                       My Discriminator                        |
  64  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  65  *    |                      Your Discriminator                       |
  66  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  67  *    |                    Desired Min TX Interval                    |
  68  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  69  *    |                   Required Min RX Interval                    |
  70  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  71  *    |                 Required Min Echo RX Interval                 |
  72  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  73  */
  74
  75 struct bfd_header_t {
  76     nd_uint8_t  version_diag;
  77     nd_uint8_t  flags;
  78     nd_uint8_t  detect_time_multiplier;
  79     nd_uint8_t  length;
  80     nd_uint32_t my_discriminator;
  81     nd_uint32_t your_discriminator;
  82     nd_uint32_t desired_min_tx_interval;
  83     nd_uint32_t required_min_rx_interval;
  84     nd_uint32_t required_min_echo_interval;
  85 };
  86
  87 /*
  88  *    An optional Authentication Header may be present
  89  *
  90  *     0                   1                   2                   3
  91  *     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
  92  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  93  *    |   Auth Type   |   Auth Len    |    Authentication Data...     |
  94  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  95  */
  96
  97 struct bfd_auth_header_t {
  98     nd_uint8_t auth_type;
  99     nd_uint8_t auth_len;
 100     nd_uint8_t auth_data;
 101     nd_uint8_t dummy; /* minimum 4 bytes */
 102 };
 103
 104 enum auth_type {
 105     AUTH_PASSWORD = 1,
 106     AUTH_MD5      = 2,
 107     AUTH_MET_MD5  = 3,
 108     AUTH_SHA1     = 4,
 109     AUTH_MET_SHA1 = 5
 110 };
 111
 112 static const struct tok bfd_v1_authentication_values[] = {
 113     { AUTH_PASSWORD, "Simple Password" },
 114     { AUTH_MD5,      "Keyed MD5" },
 115     { AUTH_MET_MD5,  "Meticulous Keyed MD5" },
 116     { AUTH_SHA1,     "Keyed SHA1" },
 117     { AUTH_MET_SHA1, "Meticulous Keyed SHA1" },
 118     { 0, NULL }
 119 };
 120
 121 enum auth_length {
 122     AUTH_PASSWORD_FIELD_MIN_LEN = 4,  /* header + password min: 3 + 1 */
 123     AUTH_PASSWORD_FIELD_MAX_LEN = 19, /* header + password max: 3 + 16 */
 124     AUTH_MD5_FIELD_LEN  = 24,
 125     AUTH_MD5_HASH_LEN   = 16,
 126     AUTH_SHA1_FIELD_LEN = 28,
 127     AUTH_SHA1_HASH_LEN  = 20
 128 };
 129
 130 #define BFD_EXTRACT_VERSION(x) (((x)&0xe0)>>5)
 131 #define BFD_EXTRACT_DIAG(x)     ((x)&0x1f)
 132
 133 static const struct tok bfd_diag_values[] = {
 134     { 0, "No Diagnostic" },
 135     { 1, "Control Detection Time Expired" },
 136     { 2, "Echo Function Failed" },
 137     { 3, "Neighbor Signaled Session Down" },
 138     { 4, "Forwarding Plane Reset" },
 139     { 5, "Path Down" },
 140     { 6, "Concatenated Path Down" },
 141     { 7, "Administratively Down" },
 142     { 8, "Reverse Concatenated Path Down" },
 143     { 0, NULL }
 144 };
 145
 146 static const struct tok bfd_port_values[] = {
 147     { BFD_CONTROL_PORT,  "Control" },
 148     { BFD_MULTIHOP_PORT, "Multihop" },
 149     { BFD_LAG_PORT,      "Lag" },
 150     { 0, NULL }
 151 };
 152
 153 #define BFD_FLAG_AUTH 0x04
 154
 155 static const struct tok bfd_v0_flag_values[] = {
 156     { 0x80, "I Hear You" },
 157     { 0x40, "Demand" },
 158     { 0x20, "Poll" },
 159     { 0x10, "Final" },
 160     { 0x08, "Control Plane Independent" },
 161     { BFD_FLAG_AUTH, "Authentication Present" },
 162     { 0x02, "Reserved" },
 163     { 0x01, "Reserved" },
 164     { 0, NULL }
 165 };
 166
 167 static const struct tok bfd_v1_flag_values[] = {
 168     { 0x20, "Poll" },
 169     { 0x10, "Final" },
 170     { 0x08, "Control Plane Independent" },
 171     { BFD_FLAG_AUTH, "Authentication Present" },
 172     { 0x02, "Demand" },
 173     { 0x01, "Multipoint" },
 174     { 0, NULL }
 175 };
 176
 177 static const struct tok bfd_v1_state_values[] = {
 178     { 0, "AdminDown" },
 179     { 1, "Down" },
 180     { 2, "Init" },
 181     { 3, "Up" },
 182     { 0, NULL }
 183 };
 184
 185 static void
 186 auth_print(netdissect_options *ndo, const u_char *pptr)
 187 {
 188         const struct bfd_auth_header_t *bfd_auth_header;
 189         uint8_t auth_type, auth_len;
 190         int i;
 191
 192         pptr += sizeof (struct bfd_header_t);
 193         bfd_auth_header = (const struct bfd_auth_header_t *)pptr;
 194         ND_TCHECK_SIZE(bfd_auth_header);
 195         auth_type = GET_U_1(bfd_auth_header->auth_type);
 196         auth_len = GET_U_1(bfd_auth_header->auth_len);
 197         ND_PRINT("\n\tAuthentication: %s (%u), length: %u",
 198                  tok2str(bfd_v1_authentication_values,"Unknown",auth_type),
 199                  auth_type, auth_len);
 200                 pptr += 2;
 201                 ND_PRINT("\n\t  Auth Key ID: %u", GET_U_1(pptr));
 202
 203         switch(auth_type) {
 204             case AUTH_PASSWORD:
 205 /*
 206  *    Simple Password Authentication Section Format
 207  *
 208  *     0                   1                   2                   3
 209  *     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
 210  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 211  *    |   Auth Type   |   Auth Len    |  Auth Key ID  |  Password...  |
 212  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 213  *    |                              ...                              |
 214  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 215  */
 216                 if (auth_len < AUTH_PASSWORD_FIELD_MIN_LEN ||
 217                     auth_len > AUTH_PASSWORD_FIELD_MAX_LEN) {
 218                     ND_PRINT("[invalid length %u]",
 219                              auth_len);
 220                     break;
 221                 }
 222                 pptr++;
 223                 ND_PRINT(", Password: ");
 224                 /* the length is equal to the password length plus three */
 225                 (void)nd_printn(ndo, pptr, auth_len - 3, NULL);
 226                 break;
 227             case AUTH_MD5:
 228             case AUTH_MET_MD5:
 229 /*
 230  *    Keyed MD5 and Meticulous Keyed MD5 Authentication Section Format
 231  *
 232  *     0                   1                   2                   3
 233  *     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
 234  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 235  *    |   Auth Type   |   Auth Len    |  Auth Key ID  |   Reserved    |
 236  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 237  *    |                        Sequence Number                        |
 238  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 239  *    |                      Auth Key/Digest...                       |
 240  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 241  *    |                              ...                              |
 242  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 243  */
 244                 if (auth_len != AUTH_MD5_FIELD_LEN) {
 245                     ND_PRINT("[invalid length %u]",
 246                              auth_len);
 247                     break;
 248                 }
 249                 pptr += 2;
 250                 ND_PRINT(", Sequence Number: 0x%08x", GET_BE_U_4(pptr));
 251                 pptr += 4;
 252                 ND_TCHECK_LEN(pptr, AUTH_MD5_HASH_LEN);
 253                 ND_PRINT("\n\t  Digest: ");
 254                 for(i = 0; i < AUTH_MD5_HASH_LEN; i++)
 255                     ND_PRINT("%02x", GET_U_1(pptr + i));
 256                 break;
 257             case AUTH_SHA1:
 258             case AUTH_MET_SHA1:
 259 /*
 260  *    Keyed SHA1 and Meticulous Keyed SHA1 Authentication Section Format
 261  *
 262  *     0                   1                   2                   3
 263  *     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
 264  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 265  *    |   Auth Type   |   Auth Len    |  Auth Key ID  |   Reserved    |
 266  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 267  *    |                        Sequence Number                        |
 268  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 269  *    |                       Auth Key/Hash...                        |
 270  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 271  *    |                              ...                              |
 272  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 273  */
 274                 if (auth_len != AUTH_SHA1_FIELD_LEN) {
 275                     ND_PRINT("[invalid length %u]",
 276                              auth_len);
 277                     break;
 278                 }
 279                 pptr += 2;
 280                 ND_PRINT(", Sequence Number: 0x%08x", GET_BE_U_4(pptr));
 281                 pptr += 4;
 282                 ND_TCHECK_LEN(pptr, AUTH_SHA1_HASH_LEN);
 283                 ND_PRINT("\n\t  Hash: ");
 284                 for(i = 0; i < AUTH_SHA1_HASH_LEN; i++)
 285                     ND_PRINT("%02x", GET_U_1(pptr + i));
 286                 break;
 287         }
 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             port == BFD_MULTIHOP_PORT ||
 297             port == BFD_LAG_PORT) {
 298             /*
 299              * Control packet.
 300              */
 301             const struct bfd_header_t *bfd_header;
 302             uint8_t version_diag;
 303             uint8_t version = 0;
 304             uint8_t flags;
 305
 306             bfd_header = (const struct bfd_header_t *)pptr;
 307             ND_TCHECK_SIZE(bfd_header);
 308             version_diag = GET_U_1(bfd_header->version_diag);
 309             version = BFD_EXTRACT_VERSION(version_diag);
 310             flags = GET_U_1(bfd_header->flags);
 311
 312             switch (version) {
 313
 314                 /* BFDv0 */
 315             case 0:
 316                 if (ndo->ndo_vflag < 1)
 317                 {
 318                     ND_PRINT("BFDv0, Control, Flags: [%s], length: %u",
 319                            bittok2str(bfd_v0_flag_values, "none", flags),
 320                            len);
 321                     return;
 322                 }
 323
 324                 ND_PRINT("BFDv0, length: %u\n\tControl, Flags: [%s], Diagnostic: %s (0x%02x)",
 325                        len,
 326                        bittok2str(bfd_v0_flag_values, "none", flags),
 327                        tok2str(bfd_diag_values,"unknown",BFD_EXTRACT_DIAG(version_diag)),
 328                        BFD_EXTRACT_DIAG(version_diag));
 329
 330                 ND_PRINT("\n\tDetection Timer Multiplier: %u (%u ms Detection time), BFD Length: %u",
 331                        GET_U_1(bfd_header->detect_time_multiplier),
 332                        GET_U_1(bfd_header->detect_time_multiplier) * GET_BE_U_4(bfd_header->desired_min_tx_interval)/1000,
 333                        GET_U_1(bfd_header->length));
 334
 335
 336                 ND_PRINT("\n\tMy Discriminator: 0x%08x",
 337                          GET_BE_U_4(bfd_header->my_discriminator));
 338                 ND_PRINT(", Your Discriminator: 0x%08x",
 339                          GET_BE_U_4(bfd_header->your_discriminator));
 340                 ND_PRINT("\n\t  Desired min Tx Interval:    %4u ms",
 341                          GET_BE_U_4(bfd_header->desired_min_tx_interval)/1000);
 342                 ND_PRINT("\n\t  Required min Rx Interval:   %4u ms",
 343                          GET_BE_U_4(bfd_header->required_min_rx_interval)/1000);
 344                 ND_PRINT("\n\t  Required min Echo Interval: %4u ms",
 345                          GET_BE_U_4(bfd_header->required_min_echo_interval)/1000);
 346
 347                 if (flags & BFD_FLAG_AUTH) {
 348                     auth_print(ndo, pptr);
 349                 }
 350                 break;
 351
 352                 /* BFDv1 */
 353             case 1:
 354                 if (ndo->ndo_vflag < 1)
 355                 {
 356                     ND_PRINT("BFDv1, %s, State %s, Flags: [%s], length: %u",
 357                            tok2str(bfd_port_values, "unknown (%u)", port),
 358                            tok2str(bfd_v1_state_values, "unknown (%u)", (flags & 0xc0) >> 6),
 359                            bittok2str(bfd_v1_flag_values, "none", flags & 0x3f),
 360                            len);
 361                     return;
 362                 }
 363
 364                 ND_PRINT("BFDv1, length: %u\n\t%s, State %s, Flags: [%s], Diagnostic: %s (0x%02x)",
 365                        len,
 366                        tok2str(bfd_port_values, "unknown (%u)", port),
 367                        tok2str(bfd_v1_state_values, "unknown (%u)", (flags & 0xc0) >> 6),
 368                        bittok2str(bfd_v1_flag_values, "none", flags & 0x3f),
 369                        tok2str(bfd_diag_values,"unknown",BFD_EXTRACT_DIAG(version_diag)),
 370                        BFD_EXTRACT_DIAG(version_diag));
 371
 372                 ND_PRINT("\n\tDetection Timer Multiplier: %u (%u ms Detection time), BFD Length: %u",
 373                        GET_U_1(bfd_header->detect_time_multiplier),
 374                        GET_U_1(bfd_header->detect_time_multiplier) * GET_BE_U_4(bfd_header->desired_min_tx_interval)/1000,
 375                        GET_U_1(bfd_header->length));
 376
 377
 378                 ND_PRINT("\n\tMy Discriminator: 0x%08x",
 379                          GET_BE_U_4(bfd_header->my_discriminator));
 380                 ND_PRINT(", Your Discriminator: 0x%08x",
 381                          GET_BE_U_4(bfd_header->your_discriminator));
 382                 ND_PRINT("\n\t  Desired min Tx Interval:    %4u ms",
 383                          GET_BE_U_4(bfd_header->desired_min_tx_interval)/1000);
 384                 ND_PRINT("\n\t  Required min Rx Interval:   %4u ms",
 385                          GET_BE_U_4(bfd_header->required_min_rx_interval)/1000);
 386                 ND_PRINT("\n\t  Required min Echo Interval: %4u ms",
 387                          GET_BE_U_4(bfd_header->required_min_echo_interval)/1000);
 388
 389                 if (flags & BFD_FLAG_AUTH) {
 390                     auth_print(ndo, pptr);
 391                 }
 392                 break;
 393
 394             default:
 395                 ND_PRINT("BFDv%u, Control, length: %u",
 396                        version,
 397                        len);
 398                 if (ndo->ndo_vflag >= 1) {
 399                     if(!print_unknown_data(ndo, pptr,"\n\t",len))
 400                         return;
 401                 }
 402                 break;
 403             }
 404         } else if (port == BFD_ECHO_PORT) {
 405             /*
 406              * Echo packet.
 407              */
 408             ND_PRINT("BFD, Echo, length: %u",
 409                    len);
 410             if (ndo->ndo_vflag >= 1) {
 411                 if(!print_unknown_data(ndo, pptr,"\n\t",len))
 412                     return;
 413             }
 414         } else {
 415             /*
 416              * Unknown packet type.
 417              */
 418             ND_PRINT("BFD, unknown (%u), length: %u",
 419                    port,
 420                    len);
 421             if (ndo->ndo_vflag >= 1) {
 422                     if(!print_unknown_data(ndo, pptr,"\n\t",len))
 423                             return;
 424             }
 425         }
 426 }