epan/dissectors/packet-mactelnet.c

   1 /* packet-mactelnet.c
   2  * Routines for MAC-Telnet dissection
   3  * Copyright 2010, Haakon Nessjoen <haakon.nessjoen@gmail.com>
   4  *
   5  * $Id$
   6  *
   7  * Wireshark - Network traffic analyzer
   8  * By Gerald Combs <gerald@wireshark.org>
   9  * Copyright 1998 Gerald Combs
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License as published by
  13  * the Free Software Foundation; either version 2 of the License, or
  14  * (at your option) any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19  * GNU General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU General Public License along
  22  * with this program; if not, write to the Free Software Foundation, Inc.,
  23  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  24  */
  25
  26 /*
  27  * Thanks to "omniflux" for dissecting the protocol by hand before me.
  28  * http://www.omniflux.com/devel/mikrotik/Mikrotik_MAC_Telnet_Procotol.txt
  29  */
  30
  31 #include "config.h"
  32
  33 #include <glib.h>
  34
  35 #include <epan/packet.h>
  36 #include <epan/prefs.h>
  37
  38 #define PROTO_TAG_MACTELNET "MAC-Telnet"
  39
  40 void proto_reg_handoff_mactelnet(void);
  41
  42 /* Initialize the protocol and registered fields */
  43 static gint proto_mactelnet = -1;
  44 static gint hf_mactelnet_control_packet = -1;
  45 static gint hf_mactelnet_type = -1;
  46 static gint hf_mactelnet_protocolver = -1;
  47 static gint hf_mactelnet_source_mac = -1;
  48 static gint hf_mactelnet_destination_mac = -1;
  49 static gint hf_mactelnet_session_id = -1;
  50 static gint hf_mactelnet_client_type = -1;
  51 static gint hf_mactelnet_databytes = -1;
  52 static gint hf_mactelnet_datatype = -1;
  53 static gint hf_mactelnet_control = -1;
  54 static gint hf_mactelnet_control_length = -1;
  55 static gint hf_mactelnet_control_encryption_key = -1;
  56 static gint hf_mactelnet_control_password = -1;
  57 static gint hf_mactelnet_control_username = -1;
  58 static gint hf_mactelnet_control_terminal = -1;
  59 static gint hf_mactelnet_control_width = -1;
  60 static gint hf_mactelnet_control_height = -1;
  61
  62 /* Global port preference */
  63 static guint global_mactelnet_port = 20561;
  64
  65 /* Control packet definition */
  66 static const guint32 control_packet = 0x563412FF;
  67
  68 /* Initialize the subtree pointers */
  69 static gint ett_mactelnet = -1;
  70 static gint ett_mactelnet_control = -1;
  71
  72 static dissector_handle_t data_handle;
  73
  74 /* Packet types */
  75 static const value_string packettypenames[] = {
  76     {   0, "Start session" },
  77     {   1, "Data" },
  78     {   2, "Acknowledge" },
  79     {   4, "Ping request" },
  80     {   5, "Ping response" },
  81     { 255, "End session" },
  82     { 0, NULL }
  83 };
  84
  85 /* Known client types */
  86 static const value_string clienttypenames[] = {
  87     { 0x0015, "MAC Telnet" },
  88     { 0x0f90, "Winbox" },
  89     { 0, NULL }
  90 };
  91
  92 /* Known control-packet types */
  93 static const value_string controlpackettypenames[] = {
  94     { 0, "Begin authentication" },
  95     { 1, "Encryption key" },
  96     { 2, "Password" },
  97     { 3, "Username" },
  98     { 4, "Terminal type" },
  99     { 5, "Terminal width" },
 100     { 6, "Terminal height" },
 101     { 9, "End authentication" },
 102     { 0, NULL }
 103 };
 104
 105
 106 static int
 107 dissect_mactelnet(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_)
 108 {
 109     proto_item *mactelnet_item;
 110     proto_tree *mactelnet_tree;
 111     proto_item *mactelnet_control_item;
 112     proto_tree *mactelnet_control_tree;
 113     int         foundping   = -1;
 114     int         foundclient = -1;
 115     int         foundserver = -1;
 116     guint16     type;
 117
 118     /* Check that there's enough data */
 119     if (tvb_length(tvb) < 18)
 120         return 0;
 121
 122     /*  Get the type byte */
 123     type = tvb_get_guint8(tvb, 1);
 124
 125     if ((type == 4) || (type == 5)) { /* Ping */
 126         foundping = 1;
 127     } else {
 128         int i = 0;
 129         while (clienttypenames[i].strptr != NULL) {
 130             if (tvb_get_ntohs(tvb, 14) == clienttypenames[i].value) {
 131                 foundserver = i;
 132                 break;
 133             }
 134             if (tvb_get_ntohs(tvb, 16) == clienttypenames[i].value) {
 135                 foundclient = i;
 136                 break;
 137             }
 138             i++;
 139         }
 140     }
 141
 142     /* Not a mactelnet packet */
 143     if ((foundping < 0) && (foundclient < 0) && (foundserver < 0)) {
 144         return 0;
 145     }
 146
 147     /* Make entries in Protocol column and Info column on summary display */
 148     col_set_str(pinfo->cinfo, COL_PROTOCOL, PROTO_TAG_MACTELNET);
 149
 150     col_add_fstr(pinfo->cinfo, COL_INFO, "%s > %s Direction: %s Type: %s",
 151                     tvb_ether_to_str(tvb, 2),
 152                     tvb_ether_to_str(tvb, 8),
 153                     ((foundclient >= 0) || (type == 4) ? "Client->Server" : "Server->Client" ),
 154                     val_to_str(type, packettypenames, "Unknown Type:0x%02x")
 155         );
 156
 157     if (tree) {
 158         guint32 offset = 0;
 159
 160         /* create display subtree for the protocol */
 161         mactelnet_item = proto_tree_add_item(tree, proto_mactelnet, tvb, 0, -1, ENC_NA);
 162         mactelnet_tree = proto_item_add_subtree(mactelnet_item, ett_mactelnet);
 163
 164         /* ver(1) */
 165         proto_tree_add_item(mactelnet_tree, hf_mactelnet_protocolver, tvb, offset, 1, ENC_NA);
 166         offset += 1;
 167
 168         /* ptype(1) */
 169         proto_tree_add_item(mactelnet_tree, hf_mactelnet_type, tvb, offset, 1, ENC_NA);
 170         offset += 1;
 171
 172         /* saddr(6) */
 173         proto_tree_add_item(mactelnet_tree, hf_mactelnet_source_mac, tvb, offset, 6, ENC_NA);
 174         offset += 6;
 175
 176         /* dstaddr(6) */
 177         proto_tree_add_item(mactelnet_tree, hf_mactelnet_destination_mac, tvb, offset, 6, ENC_NA);
 178         offset += 6;
 179
 180         if (foundserver >= 0) {
 181             /* Server to client */
 182
 183             /* sessionid(2) */
 184             proto_tree_add_item(mactelnet_tree, hf_mactelnet_session_id, tvb, offset+2, 2, ENC_BIG_ENDIAN);
 185             offset += 2;
 186
 187             /* clienttype(2) */
 188             proto_tree_add_item(mactelnet_tree, hf_mactelnet_client_type, tvb, offset-2, 2, ENC_BIG_ENDIAN);
 189             offset += 2;
 190         } else if (foundclient >= 0) {
 191             /* Client to server */
 192
 193             /* sessionid(2) */
 194             proto_tree_add_item(mactelnet_tree, hf_mactelnet_session_id, tvb, offset, 2, ENC_BIG_ENDIAN);
 195             offset += 2;
 196
 197             /* clienttype(2) */
 198             proto_tree_add_item(mactelnet_tree, hf_mactelnet_client_type, tvb, offset, 2, ENC_BIG_ENDIAN);
 199             offset += 2;
 200         } else if (foundping >= 0) {
 201             /* Skip empty data */
 202             offset += 4;
 203         }
 204
 205         if (foundping < 0) {
 206             /* counter(4) */
 207             proto_tree_add_item(mactelnet_tree, hf_mactelnet_databytes, tvb, offset, 4, ENC_BIG_ENDIAN);
 208             offset += 4;
 209         }
 210
 211         /* Data packets only */
 212         if (type == 1) {
 213             while(tvb_reported_length_remaining(tvb, offset) > 0) {
 214                 if ((tvb_reported_length_remaining(tvb, offset) > 4) && (tvb_get_ntohl(tvb, offset) == control_packet)) {
 215                     guint8  datatype;
 216                     guint32 datalength;
 217
 218                     /* Add subtree for control packet */
 219                     mactelnet_control_item = proto_tree_add_item(mactelnet_tree, hf_mactelnet_control, tvb, offset, -1, ENC_NA);
 220                     mactelnet_control_tree = proto_item_add_subtree(mactelnet_control_item, ett_mactelnet);
 221                     /* Control packet magic number (4) */
 222                     proto_tree_add_item(mactelnet_control_tree, hf_mactelnet_control_packet, tvb, offset, 4, ENC_BIG_ENDIAN);
 223                     offset += 4;
 224
 225                     /* Control packet type (1) */
 226                     datatype = tvb_get_guint8(tvb, offset);
 227                     proto_tree_add_item(mactelnet_control_tree, hf_mactelnet_datatype, tvb, offset, 1, ENC_NA);
 228                     offset += 1;
 229
 230                     /* Control packet length (4) */
 231                     datalength = tvb_get_ntohl(tvb, offset);
 232                     proto_tree_add_item(mactelnet_control_tree, hf_mactelnet_control_length, tvb, offset, 4, ENC_BIG_ENDIAN);
 233                     offset += 4;
 234
 235                     switch (datatype) {
 236                         case 1: /* Encryption Key */
 237                             proto_tree_add_item(mactelnet_control_tree, hf_mactelnet_control_encryption_key, tvb, offset, datalength, ENC_NA);
 238                             break;
 239
 240                         case 2: /* Password */
 241                             proto_tree_add_item(mactelnet_control_tree, hf_mactelnet_control_password, tvb, offset, datalength, ENC_NA);
 242                             break;
 243
 244                         case 3: /* Username */
 245                             proto_tree_add_item(mactelnet_control_tree, hf_mactelnet_control_username, tvb, offset, datalength, ENC_ASCII|ENC_NA);
 246                             break;
 247
 248                         case 4: /* Terminal type */
 249                             proto_tree_add_item(mactelnet_control_tree, hf_mactelnet_control_terminal, tvb, offset, datalength, ENC_ASCII|ENC_NA);
 250                             break;
 251
 252                         case 5: /* Terminal width */
 253                             proto_tree_add_item(mactelnet_control_tree, hf_mactelnet_control_width, tvb, offset, 2, ENC_LITTLE_ENDIAN);
 254                             break;
 255
 256                         case 6: /* Terminal height */
 257                             proto_tree_add_item(mactelnet_control_tree, hf_mactelnet_control_height, tvb, offset, 2, ENC_LITTLE_ENDIAN);
 258                             break;
 259
 260                         case 9: /* End authentication (no data) */
 261                             break;
 262                     }
 263                     proto_item_set_len (mactelnet_control_item, datalength + 9);
 264                     offset += datalength;
 265                 } else {
 266                     /* Data packet, let wireshark handle it */
 267                     tvbuff_t *next_client = tvb_new_subset_remaining(tvb, offset);
 268                     return call_dissector(data_handle, next_client, pinfo, mactelnet_tree);
 269                 }
 270             }
 271         } else if ((type == 4) || (type == 5)) {
 272             /* Data packet, let wireshark handle it */
 273             tvbuff_t *next_client = tvb_new_subset_remaining(tvb, offset);
 274             return call_dissector(data_handle, next_client, pinfo, mactelnet_tree);
 275         }
 276
 277
 278     }
 279     return tvb_reported_length(tvb);
 280 }
 281
 282
 283 void
 284 proto_register_mactelnet(void)
 285 {
 286     static hf_register_info hf[] = {
 287         { &hf_mactelnet_control_packet,
 288           { "Control Packet Magic Number", "mactelnet.control_packet",
 289             FT_UINT32, BASE_HEX, NULL, 0x0,
 290             NULL, HFILL }
 291         },
 292         { &hf_mactelnet_type,
 293           { "Type", "mactelnet.type",
 294             FT_UINT8, BASE_DEC, VALS(packettypenames), 0x0,
 295             "Packet Type", HFILL }
 296         },
 297         { &hf_mactelnet_protocolver,
 298           { "Protocol Version", "mactelnet.protocol_version",
 299             FT_UINT8, BASE_DEC, NULL, 0x0,
 300             NULL, HFILL }
 301         },
 302         { &hf_mactelnet_source_mac,
 303           { "Source MAC", "mactelnet.source_mac",
 304             FT_ETHER, BASE_NONE, NULL , 0x0,
 305             NULL, HFILL }
 306         },
 307         { &hf_mactelnet_destination_mac,
 308           { "Destination MAC", "mactelnet.destination_mac",
 309             FT_ETHER, BASE_NONE, NULL , 0x0,
 310             NULL, HFILL }
 311         },
 312         { &hf_mactelnet_session_id,
 313           { "Session ID", "mactelnet.session_id",
 314             FT_UINT16, BASE_HEX, NULL , 0x0,
 315             "Session ID for this connection", HFILL }
 316         },
 317         { &hf_mactelnet_client_type,
 318           { "Client Type", "mactelnet.client_type",
 319             FT_UINT16, BASE_HEX, VALS(clienttypenames) , 0x0,
 320             NULL, HFILL }
 321         },
 322         { &hf_mactelnet_databytes,
 323           { "Session Data Bytes", "mactelnet.session_bytes",
 324             FT_UINT32, BASE_DEC, NULL , 0x0,
 325             "Session data bytes received", HFILL }
 326         },
 327         { &hf_mactelnet_datatype,
 328           { "Data Packet Type", "mactelnet.data_type",
 329             FT_UINT8, BASE_HEX, VALS(controlpackettypenames) , 0x0,
 330             NULL, HFILL }
 331         },
 332         { &hf_mactelnet_control,
 333           { "Control Packet", "mactelnet.control",
 334             FT_NONE, BASE_NONE, NULL , 0x0,
 335             NULL, HFILL }
 336         },
 337         { &hf_mactelnet_control_length,
 338           { "Control Data Length", "mactelnet.control_length",
 339             FT_UINT32, BASE_DEC, NULL , 0x0,
 340             "Control packet length", HFILL }
 341         },
 342         { &hf_mactelnet_control_encryption_key,
 343           { "Encryption Key", "mactelnet.control_encryptionkey",
 344             FT_BYTES, BASE_NONE, NULL , 0x0,
 345             "Login encryption key", HFILL }
 346         },
 347         { &hf_mactelnet_control_password,
 348           { "Password MD5", "mactelnet.control_password",
 349             FT_BYTES, BASE_NONE, NULL , 0x0,
 350             "Null padded MD5 password", HFILL }
 351         },
 352         { &hf_mactelnet_control_username,
 353           { "Username", "mactelnet.control_username",
 354             FT_STRING, BASE_NONE, NULL , 0x0,
 355             NULL, HFILL }
 356         },
 357         { &hf_mactelnet_control_terminal,
 358           { "Terminal Type", "mactelnet.control_terminaltype",
 359             FT_STRING, BASE_NONE, NULL , 0x0,
 360             NULL, HFILL }
 361         },
 362         { &hf_mactelnet_control_width,
 363           { "Terminal Width", "mactelnet.control_width",
 364             FT_UINT16, BASE_DEC, NULL , 0x0,
 365             NULL, HFILL }
 366         },
 367         { &hf_mactelnet_control_height,
 368           { "Terminal Height", "mactelnet.control_height",
 369             FT_UINT16, BASE_DEC, NULL , 0x0,
 370             NULL, HFILL }
 371         }
 372     };
 373
 374     /* Setup protocol subtree array */
 375     static gint *ett[] = {
 376         &ett_mactelnet,
 377         &ett_mactelnet_control,
 378     };
 379
 380     module_t *mactelnet_module;
 381
 382     /* Register the protocol name and description */
 383     proto_mactelnet = proto_register_protocol ("MikroTik MAC-Telnet Protocol", PROTO_TAG_MACTELNET, "mactelnet");
 384
 385     /* Required function calls to register the header fields and subtrees used */
 386     proto_register_field_array (proto_mactelnet, hf, array_length (hf));
 387     proto_register_subtree_array (ett, array_length (ett));
 388
 389     mactelnet_module = prefs_register_protocol(proto_mactelnet, proto_reg_handoff_mactelnet);
 390
 391     prefs_register_uint_preference(mactelnet_module, "port", "UDP Port",
 392                        "MAC-Telnet UDP port if other than the default",
 393                        10, &global_mactelnet_port);
 394 }
 395
 396 void
 397 proto_reg_handoff_mactelnet(void)
 398 {
 399     static gboolean           initialized = FALSE;
 400     static guint              current_port;
 401     static dissector_handle_t mactelnet_handle;
 402
 403     if (!initialized) {
 404         mactelnet_handle = new_create_dissector_handle(dissect_mactelnet, proto_mactelnet);
 405         data_handle = find_dissector("data");
 406         initialized = TRUE;
 407     } else {
 408         dissector_delete_uint("udp.port", current_port, mactelnet_handle);
 409     }
 410
 411     current_port = global_mactelnet_port;
 412     dissector_add_uint("udp.port", current_port, mactelnet_handle);
 413 }