epan/dissectors/packet-pptp.c

   1 /* packet-pptp.c
   2  * Routines for the Point-to-Point Tunnelling Protocol (PPTP) (RFC 2637)
   3  * Brad Robel-Forrest <brad.robel-forrest@watchguard.com>
   4  *
   5  * 10/2010 - Rework PPTP Dissector
   6  * Alexis La Goutte <alexis.lagoutte at gmail dot com>
   7  *
   8  * Wireshark - Network traffic analyzer
   9  * By Gerald Combs <gerald@wireshark.org>
  10  * Copyright 1998 Gerald Combs
  11  *
  12  * SPDX-License-Identifier: GPL-2.0-or-later
  13  */
  14
  15 #include "config.h"
  16
  17 #include <epan/packet.h>
  18 #include <epan/expert.h>
  19
  20 void proto_register_pptp(void);
  21 void proto_reg_handoff_pptp(void);
  22
  23 static dissector_handle_t pptp_handle;
  24
  25 static int proto_pptp;
  26 static int hf_pptp_length;
  27 static int hf_pptp_message_type;
  28 static int hf_pptp_magic_cookie;
  29 static int hf_pptp_control_message_type;
  30 static int hf_pptp_reserved;
  31 static int hf_pptp_protocol_version;
  32 static int hf_pptp_framing_capabilities;
  33 static int hf_pptp_bearer_capabilities;
  34 static int hf_pptp_maximum_channels;
  35 static int hf_pptp_firmware_revision;
  36 static int hf_pptp_host_name;
  37 static int hf_pptp_vendor_name;
  38 static int hf_pptp_control_result;
  39 static int hf_pptp_error;
  40 static int hf_pptp_reason;
  41 static int hf_pptp_stop_result;
  42 static int hf_pptp_identifier;
  43 static int hf_pptp_echo_result;
  44 static int hf_pptp_call_id;
  45 static int hf_pptp_call_serial_number;
  46 static int hf_pptp_minimum_bps;
  47 static int hf_pptp_maximum_bps;
  48 static int hf_pptp_bearer_type;
  49 static int hf_pptp_framing_type;
  50 static int hf_pptp_packet_receive_window_size;
  51 static int hf_pptp_packet_processing_delay;
  52 static int hf_pptp_phone_number_length;
  53 static int hf_pptp_phone_number;
  54 static int hf_pptp_subaddress;
  55 static int hf_pptp_peer_call_id;
  56 static int hf_pptp_out_result;
  57 static int hf_pptp_cause;
  58 static int hf_pptp_connect_speed;
  59 static int hf_pptp_physical_channel_id;
  60 static int hf_pptp_dialed_number_length;
  61 static int hf_pptp_dialed_number;
  62 static int hf_pptp_dialing_number_length;
  63 static int hf_pptp_dialing_number;
  64 static int hf_pptp_in_result;
  65 static int hf_pptp_disc_result;
  66 static int hf_pptp_call_statistics;
  67 static int hf_pptp_crc_errors;
  68 static int hf_pptp_framing_errors;
  69 static int hf_pptp_hardware_overruns;
  70 static int hf_pptp_buffer_overruns;
  71 static int hf_pptp_timeout_errors;
  72 static int hf_pptp_alignment_errors;
  73 static int hf_pptp_send_accm;
  74 static int hf_pptp_receive_accm;
  75
  76 static int ett_pptp;
  77
  78 static expert_field ei_pptp_incorrect_magic_cookie;
  79
  80 #define TCP_PORT_PPTP           1723
  81
  82 #define MAGIC_COOKIE            0x1A2B3C4D
  83
  84 #define CNTRL_REQ       0x01
  85 #define CNTRL_REPLY     0x02
  86 #define STOP_REQ        0x03
  87 #define STOP_REPLY      0x04
  88 #define ECHO_REQ        0x05
  89 #define ECHO_REPLY      0x06
  90 #define OUT_REQ         0x07
  91 #define OUT_REPLY       0x08
  92 #define IN_REQ          0x09
  93 #define IN_REPLY        0x0A
  94 #define IN_CONNECTED    0x0B
  95 #define CLEAR_REQ       0x0C
  96 #define DISC_NOTIFY     0x0D
  97 #define ERROR_NOTIFY    0x0E
  98 #define SET_LINK        0x0F
  99
 100 static const value_string control_message_type_vals[] = {
 101   { CNTRL_REQ,    "Start-Control-Connection-Request" },
 102   { CNTRL_REPLY,  "Start-Control-Connection-Reply" },
 103   { STOP_REQ,     "Stop-Control-Connection-Request" },
 104   { STOP_REPLY,   "Stop-Control-Connection-Reply" },
 105   { ECHO_REQ,     "Echo-Request" },
 106   { ECHO_REPLY,   "Echo-Reply" },
 107   { OUT_REQ,      "Outgoing-Call-Request" },
 108   { OUT_REPLY,    "Outgoing-Call-Reply" },
 109   { IN_REQ,       "Incoming-Call-Request" },
 110   { IN_REPLY,     "Incoming-Call-Reply" },
 111   { IN_CONNECTED, "Incoming-Call-Connected" },
 112   { CLEAR_REQ,    "Call-Clear-Request" },
 113   { DISC_NOTIFY,  "Call-Disconnect-Notify" },
 114   { ERROR_NOTIFY, "WAN-Error-Notify" },
 115   { SET_LINK,     "Set-Link-Info" },
 116   { 0,  NULL },
 117 };
 118 static const value_string msgtype_vals[] = {
 119   { 1, "Control Message" },
 120   { 2, "Management Message" },
 121   { 0, NULL }
 122 };
 123
 124 static const value_string frametype_vals[] = {
 125   { 1, "Asynchronous Framing supported" },
 126   { 2, "Synchronous Framing supported"},
 127   { 3, "Either Framing supported" },
 128   { 0, NULL }
 129 };
 130
 131 static const value_string bearertype_vals[] = {
 132   { 1, "Analog access supported" },
 133   { 2, "Digital access supported" },
 134   { 3, "Either access supported" },
 135   { 0, NULL }
 136 };
 137
 138 static const value_string control_resulttype_vals[] = {
 139   { 1, "Successful channel establishment" },
 140   { 2, "General error" },
 141   { 3, "Command channel already exists" },
 142   { 4, "Requester not authorized" },
 143   { 5, "Protocol version not supported" },
 144   { 0, NULL }
 145 };
 146
 147 static const value_string errortype_vals[] = {
 148   { 0, "None" },
 149   { 1, "Not-Connected" },
 150   { 2, "Bad-Format" },
 151   { 3, "Bad-Value" },
 152   { 4, "No-Resource" },
 153   { 5, "Bad-Call ID" },
 154   { 6, "PAC-Error" },
 155   { 0, NULL }
 156 };
 157
 158 static const value_string reasontype_vals[] = {
 159   { 1, "None" },
 160   { 2, "Stop-Protocol" },
 161   { 3, "Stop-Local-Shutdown" },
 162   { 0, NULL }
 163 };
 164
 165 static const value_string stop_resulttype_vals[] = {
 166   { 1, "OK" },
 167   { 2, "General error" },
 168   { 0, NULL }
 169 };
 170
 171 static const value_string echo_resulttype_vals[] = {
 172   { 1, "OK" },
 173   { 2, "General error" },
 174   { 0, NULL }
 175 };
 176
 177 static const value_string out_resulttype_vals[] = {
 178   { 1, "Connected" },
 179   { 2, "General Error" },
 180   { 3, "No Carrier" },
 181   { 4, "Busy" },
 182   { 5, "No Dial Tone" },
 183   { 6, "Time-out" },
 184   { 7, "Do Not Accept" },
 185   { 0, NULL }
 186 };
 187
 188 static const value_string in_resulttype_vals[] = {
 189   { 1, "Connect" },
 190   { 2, "General error" },
 191   { 3, "Do Not Accept" },
 192   { 0, NULL }
 193 };
 194
 195 static const value_string disc_resulttype_vals[] = {
 196   { 1, "Lost Carrier" },
 197   { 2, "General Error" },
 198   { 3, "Admin Shutdown" },
 199   { 4, "Request" },
 200   { 0, NULL }
 201 };
 202
 203 static void
 204 dissect_unknown(tvbuff_t *tvb, int offset, packet_info *pinfo, proto_tree *tree)
 205 {
 206   call_data_dissector(tvb_new_subset_remaining(tvb, offset), pinfo, tree);
 207 }
 208
 209 static void
 210 dissect_cntrl_req(tvbuff_t *tvb, int offset, packet_info *pinfo _U_, proto_tree *tree)
 211 {
 212   if (!tree)
 213     return;
 214
 215   proto_tree_add_uint_format_value(tree, hf_pptp_protocol_version, tvb, offset,
 216                                2, tvb_get_ntohs(tvb, offset), "%u.%u",
 217                                tvb_get_uint8(tvb, offset), tvb_get_uint8(tvb, offset + 1));
 218   offset += 2;
 219
 220   proto_tree_add_item(tree, hf_pptp_reserved,             tvb, offset, 2, ENC_NA);
 221   offset += 2;
 222
 223   proto_tree_add_item(tree, hf_pptp_framing_capabilities, tvb, offset, 4, ENC_BIG_ENDIAN);
 224   offset += 4;
 225
 226   proto_tree_add_item(tree, hf_pptp_bearer_capabilities,  tvb, offset, 4, ENC_BIG_ENDIAN);
 227   offset += 4;
 228
 229   proto_tree_add_item(tree, hf_pptp_maximum_channels,     tvb, offset, 2, ENC_BIG_ENDIAN);
 230   offset += 2;
 231
 232   proto_tree_add_item(tree, hf_pptp_firmware_revision,    tvb, offset, 2, ENC_BIG_ENDIAN);
 233   offset += 2;
 234
 235   proto_tree_add_item(tree, hf_pptp_host_name,            tvb, offset, 64, ENC_ASCII);
 236   offset += 64;
 237
 238   proto_tree_add_item(tree, hf_pptp_vendor_name,          tvb, offset, 64, ENC_ASCII);
 239 }
 240
 241 static void
 242 dissect_cntrl_reply(tvbuff_t *tvb, int offset, packet_info *pinfo _U_, proto_tree *tree)
 243 {
 244   if (!tree)
 245     return;
 246
 247   proto_tree_add_uint_format_value(tree, hf_pptp_protocol_version, tvb, offset,
 248                                2, tvb_get_ntohs(tvb, offset), "%u.%u",
 249                                tvb_get_uint8(tvb, offset), tvb_get_uint8(tvb, offset + 1));
 250   offset += 2;
 251
 252   proto_tree_add_item(tree, hf_pptp_control_result,       tvb, offset, 1, ENC_BIG_ENDIAN);
 253   offset += 1;
 254
 255   proto_tree_add_item(tree, hf_pptp_error,                tvb, offset, 1, ENC_BIG_ENDIAN);
 256   offset += 1;
 257
 258   proto_tree_add_item(tree, hf_pptp_framing_capabilities, tvb, offset, 4, ENC_BIG_ENDIAN);
 259   offset += 4;
 260
 261   proto_tree_add_item(tree, hf_pptp_bearer_capabilities,  tvb, offset, 4, ENC_BIG_ENDIAN);
 262   offset += 4;
 263
 264   proto_tree_add_item(tree, hf_pptp_maximum_channels,     tvb, offset, 2, ENC_BIG_ENDIAN);
 265   offset += 2;
 266
 267   proto_tree_add_item(tree, hf_pptp_firmware_revision,    tvb, offset, 2, ENC_BIG_ENDIAN);
 268   offset += 2;
 269
 270   proto_tree_add_item(tree, hf_pptp_host_name,            tvb, offset, 64, ENC_ASCII);
 271   offset += 64;
 272
 273   proto_tree_add_item(tree, hf_pptp_vendor_name,          tvb, offset, 64, ENC_ASCII);
 274
 275 }
 276
 277 static void
 278 dissect_stop_req(tvbuff_t *tvb, int offset, packet_info *pinfo _U_, proto_tree *tree)
 279 {
 280   if (!tree)
 281     return;
 282
 283   proto_tree_add_item(tree, hf_pptp_reason,   tvb, offset, 1, ENC_BIG_ENDIAN);
 284   offset += 1;
 285   /* Reserved1 */
 286   proto_tree_add_item(tree, hf_pptp_reserved, tvb, offset, 1, ENC_NA);
 287   offset += 1;
 288   /* Reserved2 */
 289   proto_tree_add_item(tree, hf_pptp_reserved, tvb, offset, 2, ENC_NA);
 290 }
 291
 292 static void
 293 dissect_stop_reply(tvbuff_t *tvb, int offset, packet_info *pinfo _U_, proto_tree *tree)
 294 {
 295   if (!tree)
 296     return;
 297
 298   proto_tree_add_item(tree, hf_pptp_stop_result, tvb, offset, 1, ENC_BIG_ENDIAN);
 299   offset += 1;
 300
 301   proto_tree_add_item(tree, hf_pptp_error,       tvb, offset, 1, ENC_BIG_ENDIAN);
 302   offset += 1;
 303
 304   proto_tree_add_item(tree, hf_pptp_reserved,    tvb, offset, 2, ENC_NA);
 305
 306 }
 307
 308 static void
 309 dissect_echo_req(tvbuff_t *tvb, int offset, packet_info *pinfo _U_, proto_tree *tree)
 310 {
 311   if (!tree)
 312     return;
 313
 314   proto_tree_add_item(tree, hf_pptp_identifier, tvb, offset, 4, ENC_BIG_ENDIAN);
 315 }
 316
 317 static void
 318 dissect_echo_reply(tvbuff_t *tvb, int offset, packet_info *pinfo _U_, proto_tree *tree)
 319 {
 320   if (!tree)
 321     return;
 322
 323   proto_tree_add_item(tree, hf_pptp_identifier,  tvb, offset, 4, ENC_BIG_ENDIAN);
 324   offset += 4;
 325
 326   proto_tree_add_item(tree, hf_pptp_echo_result, tvb, offset, 1, ENC_BIG_ENDIAN);
 327   offset += 1;
 328
 329   proto_tree_add_item(tree, hf_pptp_error,       tvb, offset, 1, ENC_BIG_ENDIAN);
 330   offset += 1;
 331
 332   proto_tree_add_item(tree, hf_pptp_reserved,    tvb, offset, 2, ENC_NA);
 333 }
 334
 335 static void
 336 dissect_out_req(tvbuff_t *tvb, int offset, packet_info *pinfo _U_, proto_tree *tree)
 337 {
 338   if (!tree)
 339     return;
 340
 341   proto_tree_add_item(tree, hf_pptp_call_id,                    tvb, offset, 2, ENC_BIG_ENDIAN);
 342   offset += 2;
 343
 344   proto_tree_add_item(tree, hf_pptp_call_serial_number,         tvb, offset, 2, ENC_BIG_ENDIAN);
 345   offset += 2;
 346
 347   proto_tree_add_item(tree, hf_pptp_minimum_bps,                tvb, offset, 4, ENC_BIG_ENDIAN);
 348   offset += 4;
 349
 350   proto_tree_add_item(tree, hf_pptp_maximum_bps,                tvb, offset, 4, ENC_BIG_ENDIAN);
 351   offset += 4;
 352
 353   proto_tree_add_item(tree, hf_pptp_bearer_type,                tvb, offset, 4, ENC_BIG_ENDIAN);
 354   offset += 4;
 355
 356   proto_tree_add_item(tree, hf_pptp_framing_type,               tvb, offset, 4, ENC_BIG_ENDIAN);
 357   offset += 4;
 358
 359   proto_tree_add_item(tree, hf_pptp_packet_receive_window_size, tvb, offset, 2, ENC_BIG_ENDIAN);
 360   offset += 2;
 361
 362   proto_tree_add_item(tree, hf_pptp_packet_processing_delay,    tvb, offset, 2, ENC_BIG_ENDIAN);
 363   offset += 2;
 364
 365   proto_tree_add_item(tree, hf_pptp_phone_number_length,        tvb, offset, 2, ENC_BIG_ENDIAN);
 366   offset += 2;
 367
 368   proto_tree_add_item(tree, hf_pptp_reserved,                   tvb, offset, 2, ENC_NA);
 369   offset += 2;
 370
 371   proto_tree_add_item(tree, hf_pptp_phone_number,               tvb, offset, 64, ENC_ASCII);
 372   offset += 64;
 373
 374   proto_tree_add_item(tree, hf_pptp_subaddress,                 tvb, offset, 64, ENC_ASCII);
 375 }
 376
 377 static void
 378 dissect_out_reply(tvbuff_t *tvb, int offset, packet_info *pinfo _U_, proto_tree *tree)
 379 {
 380   if (!tree)
 381     return;
 382
 383   proto_tree_add_item(tree, hf_pptp_call_id,                    tvb, offset, 2, ENC_BIG_ENDIAN);
 384   offset += 2;
 385
 386   proto_tree_add_item(tree, hf_pptp_peer_call_id,               tvb, offset, 2, ENC_BIG_ENDIAN);
 387   offset += 2;
 388
 389   proto_tree_add_item(tree, hf_pptp_out_result,                 tvb, offset, 1, ENC_BIG_ENDIAN);
 390   offset += 1;
 391
 392   proto_tree_add_item(tree, hf_pptp_error,                      tvb, offset, 1, ENC_BIG_ENDIAN);
 393   offset += 1;
 394
 395   proto_tree_add_item(tree, hf_pptp_cause,                      tvb, offset, 2, ENC_BIG_ENDIAN);
 396   offset += 2;
 397
 398   proto_tree_add_item(tree, hf_pptp_connect_speed,              tvb, offset, 4, ENC_BIG_ENDIAN);
 399   offset += 4;
 400
 401   proto_tree_add_item(tree, hf_pptp_packet_receive_window_size, tvb, offset, 2, ENC_BIG_ENDIAN);
 402   offset += 2;
 403
 404   proto_tree_add_item(tree, hf_pptp_packet_processing_delay,    tvb, offset, 2, ENC_BIG_ENDIAN);
 405   offset += 2;
 406
 407   proto_tree_add_item(tree, hf_pptp_physical_channel_id,        tvb, offset, 4, ENC_BIG_ENDIAN);
 408 }
 409
 410 static void
 411 dissect_in_req(tvbuff_t *tvb, int offset, packet_info *pinfo _U_, proto_tree *tree)
 412 {
 413   if (!tree)
 414     return;
 415
 416   proto_tree_add_item(tree, hf_pptp_call_id,               tvb, offset, 2, ENC_BIG_ENDIAN);
 417   offset += 2;
 418
 419   proto_tree_add_item(tree, hf_pptp_call_serial_number,    tvb, offset, 2, ENC_BIG_ENDIAN);
 420   offset += 2;
 421
 422   proto_tree_add_item(tree, hf_pptp_bearer_type,           tvb, offset, 4, ENC_BIG_ENDIAN);
 423   offset += 4;
 424
 425   proto_tree_add_item(tree, hf_pptp_physical_channel_id,   tvb, offset, 4, ENC_BIG_ENDIAN);
 426   offset += 4;
 427
 428   proto_tree_add_item(tree, hf_pptp_dialed_number_length,  tvb, offset, 2, ENC_BIG_ENDIAN);
 429   offset += 2;
 430
 431   proto_tree_add_item(tree, hf_pptp_dialing_number_length, tvb, offset, 2, ENC_BIG_ENDIAN);
 432   offset += 2;
 433
 434   proto_tree_add_item(tree, hf_pptp_dialed_number,         tvb, offset, 64, ENC_ASCII);
 435   offset += 64;
 436
 437   proto_tree_add_item(tree, hf_pptp_dialing_number,        tvb, offset, 64, ENC_ASCII);
 438   offset += 64;
 439
 440   proto_tree_add_item(tree, hf_pptp_subaddress,            tvb, offset, 64, ENC_ASCII);
 441 }
 442
 443 static void
 444 dissect_in_reply(tvbuff_t *tvb, int offset, packet_info *pinfo _U_, proto_tree *tree)
 445 {
 446   if (!tree)
 447     return;
 448
 449   proto_tree_add_item(tree, hf_pptp_call_id,                    tvb, offset, 2, ENC_BIG_ENDIAN);
 450   offset += 2;
 451
 452   proto_tree_add_item(tree, hf_pptp_peer_call_id,               tvb, offset, 2, ENC_BIG_ENDIAN);
 453   offset += 2;
 454
 455   proto_tree_add_item(tree, hf_pptp_in_result,                  tvb, offset, 1, ENC_BIG_ENDIAN);
 456   offset += 1;
 457
 458   proto_tree_add_item(tree, hf_pptp_error,                      tvb, offset, 1, ENC_BIG_ENDIAN);
 459   offset += 1;
 460
 461   proto_tree_add_item(tree, hf_pptp_packet_receive_window_size, tvb, offset, 2, ENC_BIG_ENDIAN);
 462   offset += 2;
 463
 464   proto_tree_add_item(tree, hf_pptp_packet_processing_delay,    tvb, offset, 2, ENC_BIG_ENDIAN);
 465   offset += 2;
 466
 467   proto_tree_add_item(tree, hf_pptp_reserved,                   tvb, offset, 2, ENC_NA);
 468 }
 469
 470 static void
 471 dissect_in_connected(tvbuff_t *tvb, int offset, packet_info *pinfo _U_, proto_tree *tree)
 472 {
 473   if (!tree)
 474     return;
 475
 476   proto_tree_add_item(tree, hf_pptp_peer_call_id,               tvb, offset, 2, ENC_BIG_ENDIAN);
 477   offset += 2;
 478
 479   proto_tree_add_item(tree, hf_pptp_reserved,                   tvb, offset, 2, ENC_NA);
 480   offset += 2;
 481
 482   proto_tree_add_item(tree, hf_pptp_connect_speed,              tvb, offset, 4, ENC_BIG_ENDIAN);
 483   offset += 4;
 484
 485   proto_tree_add_item(tree, hf_pptp_packet_receive_window_size, tvb, offset, 2, ENC_BIG_ENDIAN);
 486   offset += 2;
 487
 488   proto_tree_add_item(tree, hf_pptp_packet_processing_delay,    tvb, offset, 2, ENC_BIG_ENDIAN);
 489   offset += 2;
 490
 491   proto_tree_add_item(tree, hf_pptp_framing_type,               tvb, offset, 4, ENC_BIG_ENDIAN);
 492 }
 493
 494 static void
 495 dissect_clear_req(tvbuff_t *tvb, int offset, packet_info *pinfo _U_, proto_tree *tree)
 496 {
 497   if (!tree)
 498     return;
 499
 500   proto_tree_add_item(tree, hf_pptp_call_id,  tvb, offset, 2, ENC_BIG_ENDIAN);
 501   offset += 2;
 502
 503   proto_tree_add_item(tree, hf_pptp_reserved, tvb, offset, 2, ENC_NA);
 504 }
 505
 506 static void
 507 dissect_disc_notify(tvbuff_t *tvb, int offset, packet_info *pinfo _U_, proto_tree *tree)
 508 {
 509   if (!tree)
 510     return;
 511
 512   proto_tree_add_item(tree, hf_pptp_call_id,         tvb, offset, 2, ENC_BIG_ENDIAN);
 513   offset += 2;
 514
 515   proto_tree_add_item(tree, hf_pptp_disc_result,     tvb, offset, 1, ENC_BIG_ENDIAN);
 516   offset += 1;
 517
 518   proto_tree_add_item(tree, hf_pptp_error,           tvb, offset, 1, ENC_BIG_ENDIAN);
 519   offset += 1;
 520
 521   proto_tree_add_item(tree, hf_pptp_cause,           tvb, offset, 2, ENC_BIG_ENDIAN);
 522   offset += 2;
 523
 524   proto_tree_add_item(tree, hf_pptp_reserved,        tvb, offset, 2, ENC_NA);
 525   offset += 2;
 526
 527   proto_tree_add_item(tree, hf_pptp_call_statistics, tvb, offset, 64, ENC_ASCII);
 528 }
 529
 530 static void
 531 dissect_error_notify(tvbuff_t *tvb, int offset, packet_info *pinfo _U_, proto_tree *tree)
 532 {
 533   if (!tree)
 534     return;
 535
 536   proto_tree_add_item(tree, hf_pptp_peer_call_id,      tvb, offset, 2, ENC_BIG_ENDIAN);
 537   offset += 2;
 538
 539   proto_tree_add_item(tree, hf_pptp_reserved,          tvb, offset, 2, ENC_NA);
 540   offset += 2;
 541
 542   proto_tree_add_item(tree, hf_pptp_crc_errors,        tvb, offset, 4, ENC_BIG_ENDIAN);
 543   offset += 4;
 544
 545   proto_tree_add_item(tree, hf_pptp_framing_errors,    tvb, offset, 4, ENC_BIG_ENDIAN);
 546   offset += 4;
 547
 548   proto_tree_add_item(tree, hf_pptp_hardware_overruns, tvb, offset, 4, ENC_BIG_ENDIAN);
 549   offset += 4;
 550
 551   proto_tree_add_item(tree, hf_pptp_buffer_overruns,   tvb, offset, 4, ENC_BIG_ENDIAN);
 552   offset += 4;
 553
 554   proto_tree_add_item(tree, hf_pptp_timeout_errors,    tvb, offset, 4, ENC_BIG_ENDIAN);
 555   offset += 4;
 556
 557   proto_tree_add_item(tree, hf_pptp_alignment_errors,  tvb, offset, 4, ENC_BIG_ENDIAN);
 558 }
 559
 560 static void
 561 dissect_set_link(tvbuff_t *tvb, int offset, packet_info *pinfo _U_, proto_tree *tree)
 562 {
 563   if (!tree)
 564       return;
 565
 566   proto_tree_add_item(tree, hf_pptp_peer_call_id, tvb, offset, 2, ENC_BIG_ENDIAN);
 567   offset += 2;
 568
 569   proto_tree_add_item(tree, hf_pptp_reserved,     tvb, offset, 2, ENC_NA);
 570   offset += 2;
 571
 572   proto_tree_add_item(tree, hf_pptp_send_accm,    tvb, offset, 4, ENC_BIG_ENDIAN);
 573   offset += 4;
 574
 575   proto_tree_add_item(tree, hf_pptp_receive_accm, tvb, offset, 4, ENC_BIG_ENDIAN);
 576 }
 577
 578 static int
 579 dissect_pptp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
 580 {
 581   proto_tree *pptp_tree = NULL;
 582   proto_item *item      = NULL;
 583   int         offset    = 0;
 584   uint16_t    len;
 585   uint16_t    control_message_type;
 586
 587   col_set_str(pinfo->cinfo, COL_PROTOCOL, "PPTP");
 588   col_clear(pinfo->cinfo, COL_INFO);
 589
 590   len        = tvb_get_ntohs(tvb, offset);
 591   control_message_type = tvb_get_ntohs(tvb, offset + 8);
 592
 593   col_add_str(pinfo->cinfo, COL_INFO,
 594               val_to_str(control_message_type, control_message_type_vals,
 595                          "Unknown control type (%d)"));
 596
 597   if (tree) {
 598     proto_item *ti;
 599
 600     ti = proto_tree_add_item(tree, proto_pptp, tvb, offset, len, ENC_NA);
 601     pptp_tree = proto_item_add_subtree(ti, ett_pptp);
 602
 603     proto_tree_add_item(pptp_tree, hf_pptp_length, tvb, offset, 2, ENC_BIG_ENDIAN);
 604
 605     proto_tree_add_item(pptp_tree, hf_pptp_message_type, tvb, offset+2, 2, ENC_BIG_ENDIAN);
 606
 607     item = proto_tree_add_item(pptp_tree, hf_pptp_magic_cookie, tvb, offset+4, 4, ENC_BIG_ENDIAN);
 608   }
 609
 610   if (tvb_get_ntohl(tvb, offset+4) == MAGIC_COOKIE)
 611     proto_item_append_text(item," (correct)");
 612   else {
 613     proto_item_append_text(item," (incorrect)");
 614     expert_add_info(pinfo, item, &ei_pptp_incorrect_magic_cookie);
 615   }
 616
 617   if (tree) {
 618     proto_tree_add_item(pptp_tree, hf_pptp_control_message_type, tvb, offset+8, 2, ENC_BIG_ENDIAN);
 619
 620     proto_tree_add_item(pptp_tree, hf_pptp_reserved, tvb, offset+10, 2, ENC_NA);
 621   }
 622
 623   offset += offset + 12;
 624
 625   switch(control_message_type){
 626     case CNTRL_REQ: /* Start-Control-Connection-Request */
 627       dissect_cntrl_req(tvb, offset, pinfo, pptp_tree);
 628       break;
 629     case CNTRL_REPLY: /* Start-Control-Connection-Reply */
 630       dissect_cntrl_reply(tvb, offset, pinfo, pptp_tree);
 631       break;
 632     case STOP_REQ: /* Stop-Control-Connection-Request */
 633       dissect_stop_req(tvb, offset, pinfo, pptp_tree);
 634       break;
 635     case STOP_REPLY: /* Stop-Control-Connection-Reply */
 636       dissect_stop_reply(tvb, offset, pinfo, pptp_tree);
 637       break;
 638     case ECHO_REQ: /* Echo-Request */
 639       dissect_echo_req(tvb, offset, pinfo, pptp_tree);
 640       break;
 641     case ECHO_REPLY: /* Echo-Reply */
 642       dissect_echo_reply(tvb, offset, pinfo, pptp_tree);
 643       break;
 644     case OUT_REQ: /* Outgoing-Call-Request */
 645       dissect_out_req(tvb, offset, pinfo, pptp_tree);
 646       break;
 647     case OUT_REPLY: /* Outgoing-Call-Reply */
 648       dissect_out_reply(tvb, offset, pinfo, pptp_tree);
 649       break;
 650     case IN_REQ: /* Incoming-Call-Request */
 651       dissect_in_req(tvb, offset, pinfo, pptp_tree);
 652       break;
 653     case IN_REPLY: /* Incoming-Call-Reply */
 654       dissect_in_reply(tvb, offset, pinfo, pptp_tree);
 655       break;
 656     case IN_CONNECTED: /* Incoming-Call-Connected */
 657       dissect_in_connected(tvb, offset, pinfo, pptp_tree);
 658       break;
 659     case CLEAR_REQ: /* Call-Clear-Request */
 660       dissect_clear_req(tvb, offset, pinfo, pptp_tree);
 661       break;
 662     case DISC_NOTIFY: /* Call-Disconnect-Notify */
 663       dissect_disc_notify(tvb, offset, pinfo, pptp_tree);
 664       break;
 665     case ERROR_NOTIFY: /* WAN-Error-Notify */
 666       dissect_error_notify(tvb, offset, pinfo, pptp_tree);
 667       break;
 668     case SET_LINK: /* Set-Link-Info */
 669       dissect_set_link(tvb, offset, pinfo, pptp_tree);
 670       break;
 671     default: /* Unknown Type... */
 672       dissect_unknown(tvb, offset, pinfo, pptp_tree);
 673       break;
 674   }
 675   return tvb_captured_length(tvb);
 676 }
 677
 678 void
 679 proto_register_pptp(void)
 680 {
 681   static int *ett[] = {
 682     &ett_pptp,
 683   };
 684
 685   static hf_register_info hf[] = {
 686     { &hf_pptp_length,
 687       { "Length", "pptp.length",
 688         FT_UINT16, BASE_DEC, NULL, 0x0,
 689         "Total length in octets of this PPTP message", HFILL }
 690     },
 691     { &hf_pptp_message_type,
 692       { "Message type", "pptp.type",
 693         FT_UINT16, BASE_DEC, VALS(msgtype_vals), 0x0,
 694         "PPTP message type", HFILL }
 695     },
 696     { &hf_pptp_magic_cookie,
 697       { "Magic Cookie", "pptp.magic_cookie",
 698         FT_UINT32, BASE_HEX, NULL, 0x0,
 699         "This constant value is used as a sanity check on received messages", HFILL }
 700     },
 701     { &hf_pptp_control_message_type,
 702       { "Control Message Type", "pptp.control_message_type",
 703         FT_UINT16, BASE_DEC, VALS(control_message_type_vals), 0x0,
 704         NULL, HFILL }
 705     },
 706     { &hf_pptp_reserved,
 707       { "Reserved", "pptp.reserved",
 708         FT_BYTES, BASE_NONE, NULL, 0x0,
 709         "This field MUST be 0", HFILL }
 710     },
 711     { &hf_pptp_protocol_version,
 712       { "Protocol version", "pptp.protocol_version",
 713         FT_UINT16, BASE_DEC, NULL, 0x0,
 714         "The version of the PPTP protocol", HFILL }
 715     },
 716     { &hf_pptp_framing_capabilities,
 717       { "Framing Capabilities", "pptp.framing_capabilities",
 718         FT_UINT32, BASE_DEC, VALS(frametype_vals), 0x0,
 719         "A set of bits indicating the type of framing", HFILL }
 720     },
 721     { &hf_pptp_bearer_capabilities,
 722       { "Bearer Capabilities", "pptp.bearer_capabilities",
 723         FT_UINT32, BASE_DEC, VALS(bearertype_vals), 0x0,
 724         "A set of bits indicating the type of bearer", HFILL }
 725     },
 726     { &hf_pptp_maximum_channels,
 727       { "Maximum Channels", "pptp.maximum_channels",
 728         FT_UINT16, BASE_DEC, NULL, 0x0,
 729         "The total number of individual PPP sessions this PAC can support", HFILL }
 730     },
 731     { &hf_pptp_firmware_revision,
 732       { "Firmware Revision", "pptp.firmware_revision",
 733         FT_UINT16, BASE_DEC, NULL, 0x0,
 734         "This field contains the firmware revision", HFILL }
 735     },
 736     { &hf_pptp_host_name,
 737       { "Host Name", "pptp.host_name",
 738         FT_STRING, BASE_NONE, NULL, 0x0,
 739         "A 64 octet field containing the DNS name", HFILL }
 740     },
 741     { &hf_pptp_vendor_name,
 742       { "Vendor Name", "pptp.vendor_name",
 743         FT_STRING, BASE_NONE, NULL, 0x0,
 744         "A 64 octet field containing a vendor", HFILL }
 745     },
 746     { &hf_pptp_control_result,
 747       { "Result Code", "pptp.control_result",
 748         FT_UINT8, BASE_DEC, VALS(control_resulttype_vals), 0x0,
 749         "Indicates the result of the command channel establishment attempt", HFILL }
 750     },
 751     { &hf_pptp_error,
 752       { "Error Code", "pptp.error",
 753         FT_UINT8, BASE_DEC, VALS(errortype_vals), 0x0,
 754         NULL, HFILL }
 755     },
 756     { &hf_pptp_reason,
 757       { "Reason", "pptp.reason",
 758         FT_UINT8, BASE_DEC, VALS(reasontype_vals), 0x0,
 759         "Indicates the reason for the control connection being close", HFILL }
 760     },
 761     { &hf_pptp_stop_result,
 762       { "Result Code", "pptp.stop_result",
 763         FT_UINT8, BASE_DEC, VALS(stop_resulttype_vals), 0x0,
 764         "Indicates the result of the attempt to close the control connection", HFILL }
 765     },
 766     { &hf_pptp_identifier,
 767       { "Identifier", "pptp.identifier",
 768         FT_UINT32, BASE_DEC, NULL, 0x0,
 769         NULL, HFILL }
 770     },
 771     { &hf_pptp_echo_result,
 772       { "Result Code", "pptp.echo_result",
 773         FT_UINT8, BASE_DEC, VALS(echo_resulttype_vals), 0x0,
 774         "Indicates the result of the receipt of the Echo-Request", HFILL }
 775     },
 776     { &hf_pptp_call_id,
 777       { "Call ID", "pptp.call_id",
 778         FT_UINT16, BASE_DEC, NULL, 0x0,
 779         "A unique identifier, unique to a particular PAC-PNS pair assigned by the PNS", HFILL }
 780     },
 781     { &hf_pptp_call_serial_number,
 782       { "Call Serial Number", "pptp.call_serial_number",
 783         FT_UINT16, BASE_DEC, NULL, 0x0,
 784         "An identifier assigned by the PNS to this session for the purpose of identifying this particular session in logged session information", HFILL }
 785     },
 786    { &hf_pptp_minimum_bps,
 787      { "Minimum BPS", "pptp.minimum_bps",
 788        FT_UINT32, BASE_DEC, NULL, 0x0,
 789        "The lowest acceptable line speed (in bits/second) for this session", HFILL }
 790    },
 791    { &hf_pptp_maximum_bps,
 792      { "Maximum BPS", "pptp.maximum_bps",
 793        FT_UINT32, BASE_DEC, NULL, 0x0,
 794        "The highest acceptable line speed (in bits/second) for this session", HFILL }
 795    },
 796     { &hf_pptp_framing_type,
 797       { "Framing Type", "pptp.framing_type",
 798         FT_UINT32, BASE_DEC, VALS(frametype_vals), 0x0,
 799         "A value indicating the type of PPP framing to be used for this outgoing call", HFILL }
 800     },
 801     { &hf_pptp_bearer_type,
 802       { "Bearer Type", "pptp.bearer_type",
 803         FT_UINT32, BASE_DEC, VALS(bearertype_vals), 0x0,
 804         "A value indicating the bearer capability required for this outgoing call", HFILL }
 805     },
 806     { &hf_pptp_packet_receive_window_size,
 807       { "Packet Receive Window Size", "pptp.packet_receive_window_size",
 808         FT_UINT16, BASE_DEC, NULL, 0x0,
 809         "A unique identifier, unique to a particular PAC-PNS pair assigned by the PNS", HFILL }
 810     },
 811     { &hf_pptp_packet_processing_delay,
 812       { "Packet Processing Delay", "pptp.packet_processing_delay",
 813         FT_UINT16, BASE_DEC, NULL, 0x0,
 814         "A measure of the packet processing delay that might be imposed on data sent to the PNS from the PAC", HFILL }
 815     },
 816     { &hf_pptp_phone_number_length,
 817       { "Phone Number Length", "pptp.phone_number_length",
 818         FT_UINT16, BASE_DEC, NULL, 0x0,
 819         "The actual number of valid digits in the Phone Number field", HFILL }
 820     },
 821     { &hf_pptp_phone_number,
 822       { "Phone Number", "pptp.phone_number",
 823         FT_STRING, BASE_NONE, NULL, 0x0,
 824         "The number to be dialed to establish the outgoing session", HFILL }
 825     },
 826     { &hf_pptp_subaddress,
 827       { "Subaddress", "pptp.subaddress",
 828         FT_STRING, BASE_NONE, NULL, 0x0,
 829         "A 64 octet field used to specify additional dialing information.", HFILL }
 830     },
 831     { &hf_pptp_peer_call_id,
 832       { "Peer Call ID", "pptp.peer_call_id",
 833         FT_UINT16, BASE_DEC, NULL, 0x0,
 834         "This field is set to the value received in the Call ID field of the corresponding Outgoing-Call-Request message", HFILL }
 835     },
 836     { &hf_pptp_out_result,
 837       { "Result Code", "pptp.out_result",
 838         FT_UINT8, BASE_DEC, VALS(out_resulttype_vals), 0x0,
 839         "Indicates the result of the receipt of the Outgoing-Call-Request attempt", HFILL }
 840     },
 841     { &hf_pptp_cause,
 842       { "Cause Code", "pptp.cause",
 843         FT_UINT16, BASE_DEC, NULL, 0x0,
 844         "This field gives additional information", HFILL }
 845     },
 846     { &hf_pptp_connect_speed,
 847       { "Connect Speed", "pptp.connect_speed",
 848         FT_UINT32, BASE_DEC, NULL, 0x0,
 849         "The actual connection speed used, in bits/second.", HFILL }
 850     },
 851     { &hf_pptp_physical_channel_id,
 852       { "Physical Channel ID", "pptp.physical_channel_id",
 853         FT_UINT32, BASE_DEC, NULL, 0x0,
 854         "This field is set by the PAC in a vendor-specific manner to the physical channel number used to place this call", HFILL }
 855     },
 856     { &hf_pptp_dialed_number_length,
 857       { "Dialed Number Length", "pptp.dialed_number_length",
 858         FT_UINT16, BASE_DEC, NULL, 0x0,
 859         "The actual number of valid digits in the Dialed Number field", HFILL }
 860     },
 861     { &hf_pptp_dialed_number,
 862       { "Dialed Number", "pptp.dialed_number",
 863         FT_STRING, BASE_NONE, NULL, 0x0,
 864         "The number that was dialed by the caller", HFILL }
 865     },
 866
 867     { &hf_pptp_dialing_number_length,
 868       { "Dialing Number Length", "pptp.dialing_number_length",
 869         FT_UINT16, BASE_DEC, NULL, 0x0,
 870         "The actual number of valid digits in the Dialing Number field", HFILL }
 871     },
 872     { &hf_pptp_dialing_number,
 873       { "Dialing Number", "pptp.dialing_number",
 874         FT_STRING, BASE_NONE, NULL, 0x0,
 875         "The number from which the call was placed", HFILL }
 876     },
 877     { &hf_pptp_in_result,
 878       { "Result Code", "pptp.in_result",
 879         FT_UINT8, BASE_DEC, VALS(in_resulttype_vals), 0x0,
 880         "This value indicates the result of the Incoming-Call-Request attempt", HFILL }
 881     },
 882     { &hf_pptp_disc_result,
 883       { "Result Code", "pptp.disc_result",
 884         FT_UINT8, BASE_DEC, VALS(disc_resulttype_vals), 0x0,
 885         "This value indicates the reason for the disconnect", HFILL }
 886     },
 887     { &hf_pptp_call_statistics,
 888       { "Call Statistics", "pptp.call_Statistics",
 889         FT_STRING, BASE_NONE, NULL, 0x0,
 890         "This field is an ASCII string containing vendor-specific call statistics that can be logged for diagnostic purpose", HFILL }
 891     },
 892     { &hf_pptp_crc_errors,
 893       { "CRC Errors", "pptp.crc_errors",
 894         FT_UINT32, BASE_DEC, NULL, 0x0,
 895         "Number of PPP frames received with CRC errors since session was established", HFILL }
 896     },
 897     { &hf_pptp_framing_errors,
 898       { "Framing Errors", "pptp.framing_errors",
 899         FT_UINT32, BASE_DEC, NULL, 0x0,
 900         "Number of improperly framed PPP packets received", HFILL }
 901     },
 902     { &hf_pptp_hardware_overruns,
 903       { "Hardware overruns", "pptp.hardware_overruns",
 904         FT_UINT32, BASE_DEC, NULL, 0x0,
 905         "Number of receive buffer over-runs since session was established", HFILL }
 906     },
 907     { &hf_pptp_buffer_overruns,
 908       { "Buffer overruns", "pptp.buffer_overruns",
 909         FT_UINT32, BASE_DEC, NULL, 0x0,
 910         "Number of buffer over-runs detected since session was established", HFILL }
 911     },
 912     { &hf_pptp_timeout_errors,
 913       { "Time-out Errors", "pptp.timeout_errors",
 914         FT_UINT32, BASE_DEC, NULL, 0x0,
 915         "Number of time-outs since call was established", HFILL }
 916     },
 917     { &hf_pptp_alignment_errors,
 918       { "Alignment Errors", "pptp.alignment_errors",
 919         FT_UINT32, BASE_DEC, NULL, 0x0,
 920         "Number of Alignment errors since call was established", HFILL }
 921     },
 922     { &hf_pptp_send_accm,
 923       { "Send ACCM", "pptp.send_accm",
 924         FT_UINT32, BASE_HEX, NULL, 0x0,
 925         "The send ACCM value the client should use to process outgoing PPP packets", HFILL }
 926     },
 927     { &hf_pptp_receive_accm,
 928       { "Receive ACCM", "pptp.receive_accm",
 929         FT_UINT32, BASE_HEX, NULL, 0x0,
 930         "The Receive ACCM value the client should use to process incoming PPP packets", HFILL }
 931     },
 932   };
 933
 934   static ei_register_info ei[] = {
 935      { &ei_pptp_incorrect_magic_cookie, { "pptp.magic_cookie.incorrect", PI_PROTOCOL, PI_WARN, "Incorrect Magic Cookie", EXPFILL }},
 936   };
 937
 938   expert_module_t* expert_pptp;
 939
 940   proto_pptp = proto_register_protocol("Point-to-Point Tunnelling Protocol",
 941                                        "PPTP", "pptp");
 942   pptp_handle = register_dissector("pptp", dissect_pptp, proto_pptp);
 943   proto_register_field_array(proto_pptp, hf, array_length(hf));
 944   proto_register_subtree_array(ett, array_length(ett));
 945   expert_pptp = expert_register_protocol(proto_pptp);
 946   expert_register_field_array(expert_pptp, ei, array_length(ei));
 947 }
 948
 949 void
 950 proto_reg_handoff_pptp(void)
 951 {
 952   dissector_add_uint_with_preference("tcp.port", TCP_PORT_PPTP, pptp_handle);
 953 }
 954
 955 /*
 956  * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
 957  *
 958  * Local Variables:
 959  * c-basic-offset: 2
 960  * tab-width: 8
 961  * indent-tabs-mode: nil
 962  * End:
 963  *
 964  * ex: set shiftwidth=2 tabstop=8 expandtab:
 965  * :indentSize=2:tabSize=8:noTabs=true:
 966  */