epan/dissectors/packet-gsm_ipa.c

   1 /* packet-gsm_ipa.c
   2  * Routines for packet dissection of ip.access GSM A-bis over IP
   3  * Copyright 2009 by Harald Welte <laforge@gnumonks.org>
   4  * Copyright 2009, 2010 by Holger Hans Peter Freyther <zecke@selfish.org>
   5  *
   6  * $Id$
   7  *
   8  * Wireshark - Network traffic analyzer
   9  * By Gerald Combs <gerald@wireshark.org>
  10  * Copyright 1998 Gerald Combs
  11  *
  12  * This program is free software; you can redistribute it and/or
  13  * modify it under the terms of the GNU General Public License
  14  * as published by the Free Software Foundation; either version 2
  15  * of the License, or (at your option) any later version.
  16  *
  17  * This program is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU General Public License
  23  * along with this program; if not, write to the Free Software
  24  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  25  */
  26
  27 #ifdef HAVE_CONFIG_H
  28 # include "config.h"
  29 #endif
  30
  31 #include <glib.h>
  32
  33 #include <epan/packet.h>
  34 #include <epan/ipproto.h>
  35 #include <epan/prefs.h>
  36
  37 /*
  38  * Protocol used by ip.access's nanoBTS GSM picocells to transport the GSM
  39  * A-bis interface over TCP and UDP.
  40  *
  41  * See
  42  *
  43  *      http://openbsc.osmocom.org/trac/wiki/nanoBTS
  44  *
  45  * for some information about this protocol determined by reverse-
  46  * engineering.
  47  */
  48
  49 /*
  50  * These ports are also registered for other protocols, as per
  51  *
  52  * http://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xml
  53  *
  54  * exlm-agent     3002
  55  * cgms           3003
  56  * ii-admin       3006
  57  * vrml-multi-use 4200-4299
  58  * commplex-main  5000
  59  *
  60  * But, as that document says:
  61  *
  62  ************************************************************************
  63  * PLEASE NOTE THE FOLLOWING:                                           *
  64  *                                                                      *
  65  * ASSIGNMENT OF A PORT NUMBER DOES NOT IN ANY WAY IMPLY AN             *
  66  * ENDORSEMENT OF AN APPLICATION OR PRODUCT, AND THE FACT THAT NETWORK  *
  67  * TRAFFIC IS FLOWING TO OR FROM A REGISTERED PORT DOES NOT MEAN THAT   *
  68  * IT IS "GOOD" TRAFFIC, NOR THAT IT NECESSARILY CORRESPONDS TO THE     *
  69  * ASSIGNED SERVICE. FIREWALL AND SYSTEM ADMINISTRATORS SHOULD          *
  70  * CHOOSE HOW TO CONFIGURE THEIR SYSTEMS BASED ON THEIR KNOWLEDGE OF    *
  71  * THE TRAFFIC IN QUESTION, NOT WHETHER THERE IS A PORT NUMBER          *
  72  * REGISTERED OR NOT.                                                   *
  73  ************************************************************************
  74  */
  75 #define IPA_TCP_PORTS "3002,3003,3006,4249,4250,5000"
  76 #define IPA_UDP_PORTS "3006"
  77
  78 static dissector_handle_t ipa_handle;
  79 static range_t *global_ipa_tcp_ports = NULL;
  80 static range_t *global_ipa_udp_ports = NULL;
  81 static gboolean global_ipa_in_root = FALSE;
  82 static gboolean global_ipa_in_info = FALSE;
  83
  84 /* Initialize the protocol and registered fields */
  85 static int proto_ipa = -1;
  86 static int proto_ipaccess = -1;
  87
  88 static int hf_ipa_data_len = -1;
  89 static int hf_ipa_protocol = -1;
  90 static int hf_ipa_hsl_debug = -1;
  91 static int hf_ipa_osmo_proto = -1;
  92 static int hf_ipa_osmo_ctrl_data = -1;
  93
  94 static int hf_ipaccess_msgtype = -1;
  95 static int hf_ipaccess_attr_tag = -1;
  96 static int hf_ipaccess_attr_string = -1;
  97
  98 /* Initialize the subtree pointers */
  99 static gint ett_ipa = -1;
 100 static gint ett_ipaccess = -1;
 101
 102 enum {
 103         SUB_OML,
 104         SUB_RSL,
 105         SUB_SCCP,
 106         SUB_MGCP,
 107 /*      SUB_IPACCESS, */
 108         SUB_DATA,
 109
 110         SUB_MAX
 111 };
 112
 113 static dissector_handle_t sub_handles[SUB_MAX];
 114 static dissector_table_t osmo_dissector_table;
 115
 116
 117 #define ABISIP_RSL_MAX  0x20
 118 #define HSL_DEBUG       0xdd
 119 #define OSMO_EXT        0xee
 120 #define IPA_MGCP        0xfc
 121 #define AIP_SCCP        0xfd
 122 #define ABISIP_IPACCESS 0xfe
 123 #define ABISIP_OML      0xff
 124 #define IPAC_PROTO_EXT_CTRL     0x00
 125 #define IPAC_PROTO_EXT_MGCP     0x01
 126
 127 static const value_string ipa_protocol_vals[] = {
 128         { 0x00,         "RSL" },
 129         { 0xdd,         "HSL Debug" },
 130         { 0xee,         "OSMO EXT" },
 131         { 0xfc,         "MGCP (old)" },
 132         { 0xfd,         "SCCP" },
 133         { 0xfe,         "IPA" },
 134         { 0xff,         "OML" },
 135         { 0,            NULL }
 136 };
 137
 138 static const value_string ipaccess_msgtype_vals[] = {
 139         { 0x00,         "PING?" },
 140         { 0x01,         "PONG!" },
 141         { 0x04,         "IDENTITY REQUEST" },
 142         { 0x05,         "IDENTITY RESPONSE" },
 143         { 0x06,         "IDENTITY ACK" },
 144         { 0x07,         "IDENTITY NACK" },
 145         { 0x08,         "PROXY REQUEST" },
 146         { 0x09,         "PROXY ACK" },
 147         { 0x0a,         "PROXY NACK" },
 148         { 0,            NULL }
 149 };
 150
 151 static const value_string ipaccess_idtag_vals[] = {
 152         { 0x00,         "Serial Number" },
 153         { 0x01,         "Unit Name" },
 154         { 0x02,         "Location" },
 155         { 0x03,         "Unit Type" },
 156         { 0x04,         "Equipment Version" },
 157         { 0x05,         "Software Version" },
 158         { 0x06,         "IP Address" },
 159         { 0x07,         "MAC Address" },
 160         { 0x08,         "Unit ID" },
 161         { 0,            NULL }
 162 };
 163
 164 static const value_string ipa_osmo_proto_vals[] = {
 165         { 0x00,         "CTRL" },
 166         { 0x01,         "MGCP" },
 167         { 0x02,         "LAC" },
 168         { 0x03,         "SMSC" },
 169         { 0,            NULL }
 170 };
 171
 172
 173 static gint
 174 dissect_ipa_attr(tvbuff_t *tvb, int base_offs, proto_tree *tree)
 175 {
 176         guint8 len, attr_type;
 177
 178         int offset = base_offs;
 179
 180         while (tvb_reported_length_remaining(tvb, offset) > 0) {
 181                 attr_type = tvb_get_guint8(tvb, offset);
 182
 183                 switch (attr_type) {
 184                 case 0x00:      /* a string prefixed by its length */
 185                         len = tvb_get_guint8(tvb, offset+1);
 186                         proto_tree_add_item(tree, hf_ipaccess_attr_tag,
 187                                             tvb, offset+2, 1, ENC_BIG_ENDIAN);
 188                         proto_tree_add_item(tree, hf_ipaccess_attr_string,
 189                                             tvb, offset+3, len-1, ENC_ASCII|ENC_NA);
 190                         break;
 191                 case 0x01:      /* a single-byte reqest for a certain attr */
 192                         len = 0;
 193                         proto_tree_add_item(tree, hf_ipaccess_attr_tag,
 194                                             tvb, offset+1, 1, ENC_BIG_ENDIAN);
 195                         break;
 196                 default:
 197                         len = 0;
 198                         proto_tree_add_text(tree, tvb, offset+1, 1,
 199                                             "unknown attribute type 0x%02x",
 200                                             attr_type);
 201                         break;
 202                 };
 203                 offset += len + 2;
 204         };
 205         return offset;
 206 }
 207
 208 /* Dissect an ip.access specific message */
 209 static gint
 210 dissect_ipaccess(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 211 {
 212         proto_item *ti;
 213         proto_tree *ipaccess_tree;
 214         guint8 msg_type;
 215
 216         msg_type = tvb_get_guint8(tvb, 0);
 217
 218         col_append_fstr(pinfo->cinfo, COL_INFO, "%s ",
 219                         val_to_str(msg_type, ipaccess_msgtype_vals,
 220                                    "unknown 0x%02x"));
 221         if (tree) {
 222                 ti = proto_tree_add_item(tree, proto_ipaccess, tvb, 0, -1, ENC_NA);
 223                 ipaccess_tree = proto_item_add_subtree(ti, ett_ipaccess);
 224                 proto_tree_add_item(ipaccess_tree, hf_ipaccess_msgtype,
 225                                     tvb, 0, 1, ENC_BIG_ENDIAN);
 226                 switch (msg_type) {
 227                 case 4:
 228                 case 5:
 229                         dissect_ipa_attr(tvb, 1, ipaccess_tree);
 230                         break;
 231                 }
 232         }
 233
 234         return 1;
 235 }
 236
 237 /* Dissect the osmocom extension header */
 238 static gint
 239 dissect_osmo(tvbuff_t *tvb, packet_info *pinfo, proto_tree *ipatree, proto_tree *tree)
 240 {
 241         tvbuff_t *next_tvb;
 242         guint8 osmo_proto;
 243
 244         osmo_proto = tvb_get_guint8(tvb, 0);
 245
 246         col_append_fstr(pinfo->cinfo, COL_INFO, "%s ",
 247                         val_to_str(osmo_proto, ipa_osmo_proto_vals,
 248                                    "unknown 0x%02x"));
 249         if (ipatree) {
 250                 proto_tree_add_item(ipatree, hf_ipa_osmo_proto,
 251                                     tvb, 0, 1, ENC_BIG_ENDIAN);
 252         }
 253
 254         next_tvb = tvb_new_subset_remaining(tvb, 1);
 255
 256         /* Call any subdissectors that registered for this protocol */
 257         if (dissector_try_uint(osmo_dissector_table, osmo_proto, next_tvb, pinfo, tree))
 258                 return 1;
 259
 260         /* Fallback to the standard MGCP dissector */
 261         if (osmo_proto == IPAC_PROTO_EXT_MGCP) {
 262                 call_dissector(sub_handles[SUB_MGCP], next_tvb, pinfo, tree);
 263                 return 1;
 264         /* Simply display the CTRL data as text */
 265         } else if (osmo_proto == IPAC_PROTO_EXT_CTRL) {
 266                 if (tree) {
 267                         proto_tree_add_item(tree, hf_ipa_osmo_ctrl_data, next_tvb, 0, -1, ENC_ASCII|ENC_NA);
 268                 }
 269                 return 1;
 270         }
 271
 272         call_dissector(sub_handles[SUB_DATA], next_tvb, pinfo, tree);
 273
 274         return 1;
 275 }
 276
 277
 278
 279 /* Code to actually dissect the packets */
 280 static void
 281 dissect_ipa(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 282 {
 283         gint remaining;
 284         gint header_length = 3;
 285         int offset = 0;
 286
 287         col_set_str(pinfo->cinfo, COL_PROTOCOL, "IPA");
 288         col_clear(pinfo->cinfo, COL_INFO);
 289
 290         while ((remaining = tvb_reported_length_remaining(tvb, offset)) > 0) {
 291                 proto_item *ti;
 292                 proto_tree *ipa_tree = NULL;
 293                 guint16 len, msg_type;
 294                 tvbuff_t *next_tvb;
 295
 296                 len = tvb_get_ntohs(tvb, offset);
 297                 msg_type = tvb_get_guint8(tvb, offset+2);
 298
 299                 col_append_fstr(pinfo->cinfo, COL_INFO, "%s ",
 300                                 val_to_str(msg_type, ipa_protocol_vals,
 301                                            "unknown 0x%02x"));
 302
 303                 /*
 304                  * The IPA header is different depending on the transport protocol.
 305                  * With UDP there seems to be a fourth byte for the IPA header.
 306                  * We attempt to detect this by checking if the length from the
 307                  * header + four bytes of the IPA header equals the remaining size.
 308                  */
 309                 if ((pinfo->ipproto == IP_PROTO_UDP) && (len + 4 == remaining)) {
 310                         header_length++;
 311                 }
 312
 313                 if (tree) {
 314                         ti = proto_tree_add_protocol_format(tree, proto_ipa,
 315                                         tvb, offset, len+header_length,
 316                                         "IPA protocol ip.access, type: %s",
 317                                         val_to_str(msg_type, ipa_protocol_vals,
 318                                                    "unknown 0x%02x"));
 319                         ipa_tree = proto_item_add_subtree(ti, ett_ipa);
 320                         proto_tree_add_item(ipa_tree, hf_ipa_data_len,
 321                                             tvb, offset, 2, ENC_BIG_ENDIAN);
 322                         proto_tree_add_item(ipa_tree, hf_ipa_protocol,
 323                                             tvb, offset+2, 1, ENC_BIG_ENDIAN);
 324                 }
 325
 326                 next_tvb = tvb_new_subset(tvb, offset+header_length, len, len);
 327
 328                 switch (msg_type) {
 329                 case ABISIP_OML:
 330                         /* hand this off to the standard A-bis OML dissector */
 331                         if (sub_handles[SUB_OML])
 332                                 call_dissector(sub_handles[SUB_OML], next_tvb,
 333                                                  pinfo, tree);
 334                         break;
 335                 case ABISIP_IPACCESS:
 336                         dissect_ipaccess(next_tvb, pinfo, tree);
 337                         break;
 338                 case AIP_SCCP:
 339                         /* hand this off to the standard SCCP dissector */
 340                         call_dissector(sub_handles[SUB_SCCP], next_tvb, pinfo, tree);
 341                         break;
 342                 case IPA_MGCP:
 343                         /* hand this off to the standard MGCP dissector */
 344                         call_dissector(sub_handles[SUB_MGCP], next_tvb, pinfo, tree);
 345                         break;
 346                 case OSMO_EXT:
 347                         dissect_osmo(next_tvb, pinfo, ipa_tree, tree);
 348                         break;
 349                 case HSL_DEBUG:
 350                         if (tree) {
 351                                 proto_tree_add_item(ipa_tree, hf_ipa_hsl_debug,
 352                                                     next_tvb, 0, len, ENC_ASCII|ENC_NA);
 353                                 if (global_ipa_in_root == TRUE)
 354                                         proto_tree_add_item(tree, hf_ipa_hsl_debug,
 355                                                             next_tvb, 0, len, ENC_ASCII|ENC_NA);
 356                         }
 357                         if (global_ipa_in_info == TRUE)
 358                                 col_append_fstr(pinfo->cinfo, COL_INFO, "%s ",
 359                                                 tvb_get_ephemeral_stringz(next_tvb, 0, NULL));
 360                         break;
 361                 default:
 362                         if (msg_type < ABISIP_RSL_MAX) {
 363                                 /* hand this off to the standard A-bis RSL dissector */
 364                                 call_dissector(sub_handles[SUB_RSL], next_tvb, pinfo, tree);
 365                         }
 366                         break;
 367                 }
 368                 offset += len + header_length;
 369         }
 370 }
 371
 372 void proto_reg_handoff_gsm_ipa(void);
 373
 374 void proto_register_ipa(void)
 375 {
 376         module_t *ipa_module;
 377
 378         static hf_register_info hf[] = {
 379                 {&hf_ipa_data_len,
 380                  {"DataLen", "ipa.data_len",
 381                   FT_UINT16, BASE_DEC, NULL, 0x0,
 382                   "The length of the data (in bytes)", HFILL}
 383                  },
 384                 {&hf_ipa_protocol,
 385                  {"Protocol", "ipa.protocol",
 386                   FT_UINT8, BASE_HEX, VALS(ipa_protocol_vals), 0x0,
 387                   "The IPA Sub-Protocol", HFILL}
 388                  },
 389                 {&hf_ipa_hsl_debug,
 390                  {"Debug Message", "ipa.hsl_debug",
 391                   FT_STRING, BASE_NONE, NULL, 0,
 392                   "Hay Systems Limited debug message", HFILL}
 393                 },
 394                 {&hf_ipa_osmo_proto,
 395                  {"Osmo ext protocol", "ipa.osmo.protocol",
 396                   FT_UINT8, BASE_HEX, VALS(ipa_osmo_proto_vals), 0x0,
 397                   "The osmo extension protocol", HFILL}
 398                 },
 399
 400                 {&hf_ipa_osmo_ctrl_data,
 401                  {"CTRL data", "ipa.ctrl.data",
 402                   FT_STRING, BASE_NONE, NULL, 0x0,
 403                   "Control interface data", HFILL}
 404                 },
 405
 406         };
 407         static hf_register_info hf_ipa[] = {
 408                 {&hf_ipaccess_msgtype,
 409                  {"MessageType", "ipaccess.msg_type",
 410                   FT_UINT8, BASE_HEX, VALS(ipaccess_msgtype_vals), 0x0,
 411                   "Type of ip.access messsage", HFILL}
 412                  },
 413                 {&hf_ipaccess_attr_tag,
 414                  {"Tag", "ipaccess.attr_tag",
 415                   FT_UINT8, BASE_HEX, VALS(ipaccess_idtag_vals), 0x0,
 416                   "Attribute Tag", HFILL}
 417                  },
 418                 {&hf_ipaccess_attr_string,
 419                  {"String", "ipaccess.attr_string",
 420                   FT_STRING, BASE_NONE, NULL, 0x0,
 421                   "String attribute", HFILL}
 422                  },
 423         };
 424
 425         static gint *ett[] = {
 426                 &ett_ipa,
 427                 &ett_ipaccess,
 428         };
 429
 430         proto_ipa =
 431             proto_register_protocol("GSM over IP protocol as used by ip.access",
 432                                     "GSM over IP", "gsm_ipa");
 433         proto_ipaccess =
 434             proto_register_protocol("GSM over IP ip.access CCM sub-protocol",
 435                                     "IPA", "ipaccess");
 436
 437         proto_register_field_array(proto_ipa, hf, array_length(hf));
 438         proto_register_field_array(proto_ipaccess, hf_ipa, array_length(hf_ipa));
 439         proto_register_subtree_array(ett, array_length(ett));
 440
 441         register_dissector("gsm_ipa", dissect_ipa, proto_ipa);
 442
 443         /* Register table for subdissectors */
 444         osmo_dissector_table = register_dissector_table("ipa.osmo.protocol",
 445                                         "ip.access Protocol", FT_UINT8, BASE_DEC);
 446
 447
 448         range_convert_str(&global_ipa_tcp_ports, IPA_TCP_PORTS, MAX_TCP_PORT);
 449         range_convert_str(&global_ipa_udp_ports, IPA_UDP_PORTS, MAX_UDP_PORT);
 450         ipa_module = prefs_register_protocol(proto_ipa,
 451                                              proto_reg_handoff_gsm_ipa);
 452
 453         prefs_register_range_preference(ipa_module, "tcp_ports",
 454                                         "GSM IPA TCP Port(s)",
 455                                         "Set the port(s) for ip.access IPA"
 456                                         " (default: " IPA_TCP_PORTS ")",
 457                                         &global_ipa_tcp_ports, MAX_TCP_PORT);
 458         prefs_register_range_preference(ipa_module, "udp_ports",
 459                                         "GSM IPA UDP Port(s)",
 460                                         "Set the port(s) for ip.access IPA"
 461                                         " (default: " IPA_UDP_PORTS ")",
 462                                         &global_ipa_udp_ports, MAX_UDP_PORT);
 463
 464         prefs_register_bool_preference(ipa_module, "hsl_debug_in_root_tree",
 465                                         "HSL Debug messages in root protocol tree",
 466                                         NULL, &global_ipa_in_root);
 467         prefs_register_bool_preference(ipa_module, "hsl_debug_in_info",
 468                                         "HSL Debug messages in INFO column",
 469                                         NULL, &global_ipa_in_info);
 470 }
 471
 472 static void ipa_tcp_delete_callback(guint32 port)
 473 {
 474         if (port)
 475                 dissector_delete_uint("tcp.port", port, ipa_handle);
 476 }
 477
 478 static void ipa_udp_delete_callback(guint32 port)
 479 {
 480         if (port)
 481                 dissector_delete_uint("udp.port", port, ipa_handle);
 482 }
 483
 484 static void ipa_tcp_add_callback(guint32 port)
 485 {
 486         if (port)
 487                 dissector_add_uint("tcp.port", port, ipa_handle);
 488 }
 489
 490 static void ipa_udp_add_callback(guint32 port)
 491 {
 492         if (port)
 493                 dissector_add_uint("udp.port", port, ipa_handle);
 494 }
 495
 496 void proto_reg_handoff_gsm_ipa(void)
 497 {
 498         static gboolean ipa_initialized = FALSE;
 499         static range_t *ipa_tcp_ports, *ipa_udp_ports;
 500
 501         if (!ipa_initialized) {
 502                 sub_handles[SUB_RSL] = find_dissector("gsm_abis_rsl");
 503                 sub_handles[SUB_OML] = find_dissector("gsm_abis_oml");
 504                 sub_handles[SUB_SCCP] = find_dissector("sccp");
 505                 sub_handles[SUB_MGCP] = find_dissector("mgcp");
 506                 sub_handles[SUB_DATA] = find_dissector("data");
 507
 508                 ipa_handle = create_dissector_handle(dissect_ipa, proto_ipa);
 509                 ipa_initialized = TRUE;
 510         } else {
 511                 range_foreach(ipa_tcp_ports, ipa_tcp_delete_callback);
 512                 g_free(ipa_tcp_ports);
 513                 range_foreach(ipa_udp_ports, ipa_udp_delete_callback);
 514                 g_free(ipa_udp_ports);
 515         }
 516
 517         ipa_tcp_ports = range_copy(global_ipa_tcp_ports);
 518         ipa_udp_ports = range_copy(global_ipa_udp_ports);
 519
 520         range_foreach(ipa_tcp_ports, ipa_tcp_add_callback);
 521         range_foreach(ipa_udp_ports, ipa_udp_add_callback);
 522 }