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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  25  */
  26
  27 #include "config.h"
  28
  29 #include <glib.h>
  30
  31 #include <epan/packet.h>
  32 #include <epan/ipproto.h>
  33 #include <epan/prefs.h>
  34
  35 /*
  36  * Protocol used by ip.access's nanoBTS/nanoGSM GSM picocells:
  37  *
  38  *      http://www.ipaccess.com/en/nanoGSM-picocell
  39  *
  40  * to transport the GSM A-bis interface over TCP and UDP.
  41  *
  42  * See
  43  *
  44  *      http://openbsc.osmocom.org/trac/wiki/nanoBTS
  45  *
  46  * for some information about this protocol determined by reverse-
  47  * engineering.
  48  */
  49
  50 /*
  51  * These ports are also registered for other protocols, as per
  52  *
  53  * http://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xml
  54  *
  55  * exlm-agent     3002
  56  * cgms           3003
  57  * ii-admin       3006
  58  * vrml-multi-use 4200-4299
  59  * commplex-main  5000
  60  *
  61  * But, as that document says:
  62  *
  63  ************************************************************************
  64  * PLEASE NOTE THE FOLLOWING:                                           *
  65  *                                                                      *
  66  * ASSIGNMENT OF A PORT NUMBER DOES NOT IN ANY WAY IMPLY AN             *
  67  * ENDORSEMENT OF AN APPLICATION OR PRODUCT, AND THE FACT THAT NETWORK  *
  68  * TRAFFIC IS FLOWING TO OR FROM A REGISTERED PORT DOES NOT MEAN THAT   *
  69  * IT IS "GOOD" TRAFFIC, NOR THAT IT NECESSARILY CORRESPONDS TO THE     *
  70  * ASSIGNED SERVICE. FIREWALL AND SYSTEM ADMINISTRATORS SHOULD          *
  71  * CHOOSE HOW TO CONFIGURE THEIR SYSTEMS BASED ON THEIR KNOWLEDGE OF    *
  72  * THE TRAFFIC IN QUESTION, NOT WHETHER THERE IS A PORT NUMBER          *
  73  * REGISTERED OR NOT.                                                   *
  74  ************************************************************************
  75  */
  76 #define IPA_TCP_PORTS "3002,3003,3006,4249,4250,5000"
  77 #define IPA_UDP_PORTS "3006"
  78 #define IPA_UDP_PORTS_DEFAULT "0"
  79
  80 static dissector_handle_t ipa_handle;
  81 static range_t *global_ipa_tcp_ports = NULL;
  82 static range_t *global_ipa_udp_ports = NULL;
  83 static gboolean global_ipa_in_root = FALSE;
  84 static gboolean global_ipa_in_info = FALSE;
  85
  86 /* Initialize the protocol and registered fields */
  87 static int proto_ipa = -1;
  88 static int proto_ipaccess = -1;
  89
  90 static int hf_ipa_data_len = -1;
  91 static int hf_ipa_protocol = -1;
  92 static int hf_ipa_hsl_debug = -1;
  93 static int hf_ipa_osmo_proto = -1;
  94 static int hf_ipa_osmo_ctrl_data = -1;
  95
  96 static int hf_ipaccess_msgtype = -1;
  97 static int hf_ipaccess_attr_tag = -1;
  98 static int hf_ipaccess_attr_string = -1;
  99
 100 /* Initialize the subtree pointers */
 101 static gint ett_ipa = -1;
 102 static gint ett_ipaccess = -1;
 103
 104 enum {
 105         SUB_OML,
 106         SUB_RSL,
 107         SUB_SCCP,
 108         SUB_MGCP,
 109 /*      SUB_IPACCESS, */
 110         SUB_DATA,
 111
 112         SUB_MAX
 113 };
 114
 115 static dissector_handle_t sub_handles[SUB_MAX];
 116 static dissector_table_t osmo_dissector_table;
 117
 118
 119 #define ABISIP_RSL_MAX  0x20
 120 #define HSL_DEBUG       0xdd
 121 #define OSMO_EXT        0xee
 122 #define IPA_MGCP        0xfc
 123 #define AIP_SCCP        0xfd
 124 #define ABISIP_IPACCESS 0xfe
 125 #define ABISIP_OML      0xff
 126 #define IPAC_PROTO_EXT_CTRL     0x00
 127 #define IPAC_PROTO_EXT_MGCP     0x01
 128
 129 static const value_string ipa_protocol_vals[] = {
 130         { 0x00,         "RSL" },
 131         { 0xdd,         "HSL Debug" },
 132         { 0xee,         "OSMO EXT" },
 133         { 0xfc,         "MGCP (old)" },
 134         { 0xfd,         "SCCP" },
 135         { 0xfe,         "IPA" },
 136         { 0xff,         "OML" },
 137         { 0,            NULL }
 138 };
 139
 140 static const value_string ipaccess_msgtype_vals[] = {
 141         { 0x00,         "PING?" },
 142         { 0x01,         "PONG!" },
 143         { 0x04,         "IDENTITY REQUEST" },
 144         { 0x05,         "IDENTITY RESPONSE" },
 145         { 0x06,         "IDENTITY ACK" },
 146         { 0x07,         "IDENTITY NACK" },
 147         { 0x08,         "PROXY REQUEST" },
 148         { 0x09,         "PROXY ACK" },
 149         { 0x0a,         "PROXY NACK" },
 150         { 0,            NULL }
 151 };
 152
 153 static const value_string ipaccess_idtag_vals[] = {
 154         { 0x00,         "Serial Number" },
 155         { 0x01,         "Unit Name" },
 156         { 0x02,         "Location" },
 157         { 0x03,         "Unit Type" },
 158         { 0x04,         "Equipment Version" },
 159         { 0x05,         "Software Version" },
 160         { 0x06,         "IP Address" },
 161         { 0x07,         "MAC Address" },
 162         { 0x08,         "Unit ID" },
 163         { 0,            NULL }
 164 };
 165
 166 static const value_string ipa_osmo_proto_vals[] = {
 167         { 0x00,         "CTRL" },
 168         { 0x01,         "MGCP" },
 169         { 0x02,         "LAC" },
 170         { 0x03,         "SMSC" },
 171         { 0,            NULL }
 172 };
 173
 174
 175 static gint
 176 dissect_ipa_attr(tvbuff_t *tvb, int base_offs, proto_tree *tree)
 177 {
 178         guint8 len, attr_type;
 179
 180         int offset = base_offs;
 181
 182         while (tvb_reported_length_remaining(tvb, offset) > 0) {
 183                 attr_type = tvb_get_guint8(tvb, offset);
 184
 185                 switch (attr_type) {
 186                 case 0x00:      /* a string prefixed by its length */
 187                         len = tvb_get_guint8(tvb, offset+1);
 188                         proto_tree_add_item(tree, hf_ipaccess_attr_tag,
 189                                             tvb, offset+2, 1, ENC_BIG_ENDIAN);
 190                         proto_tree_add_item(tree, hf_ipaccess_attr_string,
 191                                             tvb, offset+3, len-1, ENC_ASCII|ENC_NA);
 192                         break;
 193                 case 0x01:      /* a single-byte reqest for a certain attr */
 194                         len = 0;
 195                         proto_tree_add_item(tree, hf_ipaccess_attr_tag,
 196                                             tvb, offset+1, 1, ENC_BIG_ENDIAN);
 197                         break;
 198                 default:
 199                         len = 0;
 200                         proto_tree_add_text(tree, tvb, offset+1, 1,
 201                                             "unknown attribute type 0x%02x",
 202                                             attr_type);
 203                         break;
 204                 };
 205                 offset += len + 2;
 206         };
 207         return offset;
 208 }
 209
 210 /* Dissect an ip.access specific message */
 211 static gint
 212 dissect_ipaccess(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 213 {
 214         proto_item *ti;
 215         proto_tree *ipaccess_tree;
 216         guint8 msg_type;
 217
 218         msg_type = tvb_get_guint8(tvb, 0);
 219
 220         col_append_fstr(pinfo->cinfo, COL_INFO, "%s ",
 221                         val_to_str(msg_type, ipaccess_msgtype_vals,
 222                                    "unknown 0x%02x"));
 223         if (tree) {
 224                 ti = proto_tree_add_item(tree, proto_ipaccess, tvb, 0, -1, ENC_NA);
 225                 ipaccess_tree = proto_item_add_subtree(ti, ett_ipaccess);
 226                 proto_tree_add_item(ipaccess_tree, hf_ipaccess_msgtype,
 227                                     tvb, 0, 1, ENC_BIG_ENDIAN);
 228                 switch (msg_type) {
 229                 case 4:
 230                 case 5:
 231                         dissect_ipa_attr(tvb, 1, ipaccess_tree);
 232                         break;
 233                 }
 234         }
 235
 236         return 1;
 237 }
 238
 239 /* Dissect the osmocom extension header */
 240 static gint
 241 dissect_osmo(tvbuff_t *tvb, packet_info *pinfo, proto_tree *ipatree, proto_tree *tree)
 242 {
 243         tvbuff_t *next_tvb;
 244         guint8 osmo_proto;
 245
 246         osmo_proto = tvb_get_guint8(tvb, 0);
 247
 248         col_append_fstr(pinfo->cinfo, COL_INFO, "%s ",
 249                         val_to_str(osmo_proto, ipa_osmo_proto_vals,
 250                                    "unknown 0x%02x"));
 251         if (ipatree) {
 252                 proto_tree_add_item(ipatree, hf_ipa_osmo_proto,
 253                                     tvb, 0, 1, ENC_BIG_ENDIAN);
 254         }
 255
 256         next_tvb = tvb_new_subset_remaining(tvb, 1);
 257
 258         /* Call any subdissectors that registered for this protocol */
 259         if (dissector_try_uint(osmo_dissector_table, osmo_proto, next_tvb, pinfo, tree))
 260                 return 1;
 261
 262         /* Fallback to the standard MGCP dissector */
 263         if (osmo_proto == IPAC_PROTO_EXT_MGCP) {
 264                 call_dissector(sub_handles[SUB_MGCP], next_tvb, pinfo, tree);
 265                 return 1;
 266         /* Simply display the CTRL data as text */
 267         } else if (osmo_proto == IPAC_PROTO_EXT_CTRL) {
 268                 if (tree) {
 269                         proto_tree_add_item(tree, hf_ipa_osmo_ctrl_data, next_tvb, 0, -1, ENC_ASCII|ENC_NA);
 270                 }
 271                 return 1;
 272         }
 273
 274         call_dissector(sub_handles[SUB_DATA], next_tvb, pinfo, tree);
 275
 276         return 1;
 277 }
 278
 279
 280
 281 /* Code to actually dissect the packets */
 282 static void
 283 dissect_ipa(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 284 {
 285         gint remaining;
 286         gint header_length = 3;
 287         int offset = 0;
 288
 289         col_set_str(pinfo->cinfo, COL_PROTOCOL, "IPA");
 290         col_clear(pinfo->cinfo, COL_INFO);
 291
 292         while ((remaining = tvb_reported_length_remaining(tvb, offset)) > 0) {
 293                 proto_item *ti;
 294                 proto_tree *ipa_tree = NULL;
 295                 guint16 len, msg_type;
 296                 tvbuff_t *next_tvb;
 297
 298                 len = tvb_get_ntohs(tvb, offset);
 299                 msg_type = tvb_get_guint8(tvb, offset+2);
 300
 301                 col_append_fstr(pinfo->cinfo, COL_INFO, "%s ",
 302                                 val_to_str(msg_type, ipa_protocol_vals,
 303                                            "unknown 0x%02x"));
 304
 305                 /*
 306                  * The IPA header is different depending on the transport protocol.
 307                  * With UDP there seems to be a fourth byte for the IPA header.
 308                  * We attempt to detect this by checking if the length from the
 309                  * header + four bytes of the IPA header equals the remaining size.
 310                  */
 311                 if ((pinfo->ipproto == IP_PROTO_UDP) && (len + 4 == remaining)) {
 312                         header_length++;
 313                 }
 314
 315                 if (tree) {
 316                         ti = proto_tree_add_protocol_format(tree, proto_ipa,
 317                                         tvb, offset, len+header_length,
 318                                         "IPA protocol ip.access, type: %s",
 319                                         val_to_str(msg_type, ipa_protocol_vals,
 320                                                    "unknown 0x%02x"));
 321                         ipa_tree = proto_item_add_subtree(ti, ett_ipa);
 322                         proto_tree_add_item(ipa_tree, hf_ipa_data_len,
 323                                             tvb, offset, 2, ENC_BIG_ENDIAN);
 324                         proto_tree_add_item(ipa_tree, hf_ipa_protocol,
 325                                             tvb, offset+2, 1, ENC_BIG_ENDIAN);
 326                 }
 327
 328                 next_tvb = tvb_new_subset(tvb, offset+header_length, len, len);
 329
 330                 switch (msg_type) {
 331                 case ABISIP_OML:
 332                         /* hand this off to the standard A-bis OML dissector */
 333                         if (sub_handles[SUB_OML])
 334                                 call_dissector(sub_handles[SUB_OML], next_tvb,
 335                                                  pinfo, tree);
 336                         break;
 337                 case ABISIP_IPACCESS:
 338                         dissect_ipaccess(next_tvb, pinfo, tree);
 339                         break;
 340                 case AIP_SCCP:
 341                         /* hand this off to the standard SCCP dissector */
 342                         call_dissector(sub_handles[SUB_SCCP], next_tvb, pinfo, tree);
 343                         break;
 344                 case IPA_MGCP:
 345                         /* hand this off to the standard MGCP dissector */
 346                         call_dissector(sub_handles[SUB_MGCP], next_tvb, pinfo, tree);
 347                         break;
 348                 case OSMO_EXT:
 349                         dissect_osmo(next_tvb, pinfo, ipa_tree, tree);
 350                         break;
 351                 case HSL_DEBUG:
 352                         if (tree) {
 353                                 proto_tree_add_item(ipa_tree, hf_ipa_hsl_debug,
 354                                                     next_tvb, 0, len, ENC_ASCII|ENC_NA);
 355                                 if (global_ipa_in_root == TRUE)
 356                                         proto_tree_add_item(tree, hf_ipa_hsl_debug,
 357                                                             next_tvb, 0, len, ENC_ASCII|ENC_NA);
 358                         }
 359                         if (global_ipa_in_info == TRUE)
 360                                 col_append_fstr(pinfo->cinfo, COL_INFO, "%s ",
 361                                                 tvb_get_stringz(wmem_packet_scope(), next_tvb, 0, NULL));
 362                         break;
 363                 default:
 364                         if (msg_type < ABISIP_RSL_MAX) {
 365                                 /* hand this off to the standard A-bis RSL dissector */
 366                                 call_dissector(sub_handles[SUB_RSL], next_tvb, pinfo, tree);
 367                         }
 368                         break;
 369                 }
 370                 offset += len + header_length;
 371         }
 372 }
 373
 374 void proto_reg_handoff_gsm_ipa(void);
 375
 376 void proto_register_ipa(void)
 377 {
 378         module_t *ipa_module;
 379
 380         static hf_register_info hf[] = {
 381                 {&hf_ipa_data_len,
 382                  {"DataLen", "gsm_ipa.data_len",
 383                   FT_UINT16, BASE_DEC, NULL, 0x0,
 384                   "The length of the data (in bytes)", HFILL}
 385                  },
 386                 {&hf_ipa_protocol,
 387                  {"Protocol", "gsm_ipa.protocol",
 388                   FT_UINT8, BASE_HEX, VALS(ipa_protocol_vals), 0x0,
 389                   "The IPA Sub-Protocol", HFILL}
 390                  },
 391                 {&hf_ipa_hsl_debug,
 392                  {"Debug Message", "gsm_ipa.hsl_debug",
 393                   FT_STRING, BASE_NONE, NULL, 0,
 394                   "Hay Systems Limited debug message", HFILL}
 395                 },
 396                 {&hf_ipa_osmo_proto,
 397                  {"Osmo ext protocol", "gsm_ipa.osmo.protocol",
 398                   FT_UINT8, BASE_HEX, VALS(ipa_osmo_proto_vals), 0x0,
 399                   "The osmo extension protocol", HFILL}
 400                 },
 401
 402                 {&hf_ipa_osmo_ctrl_data,
 403                  {"CTRL data", "gsm_ipa.ctrl.data",
 404                   FT_STRING, BASE_NONE, NULL, 0x0,
 405                   "Control interface data", HFILL}
 406                 },
 407
 408         };
 409         static hf_register_info hf_ipa[] = {
 410                 {&hf_ipaccess_msgtype,
 411                  {"MessageType", "ipaccess.msg_type",
 412                   FT_UINT8, BASE_HEX, VALS(ipaccess_msgtype_vals), 0x0,
 413                   "Type of ip.access messsage", HFILL}
 414                  },
 415                 {&hf_ipaccess_attr_tag,
 416                  {"Tag", "ipaccess.attr_tag",
 417                   FT_UINT8, BASE_HEX, VALS(ipaccess_idtag_vals), 0x0,
 418                   "Attribute Tag", HFILL}
 419                  },
 420                 {&hf_ipaccess_attr_string,
 421                  {"String", "ipaccess.attr_string",
 422                   FT_STRING, BASE_NONE, NULL, 0x0,
 423                   "String attribute", HFILL}
 424                  },
 425         };
 426
 427         static gint *ett[] = {
 428                 &ett_ipa,
 429                 &ett_ipaccess,
 430         };
 431
 432         proto_ipa =
 433             proto_register_protocol("GSM over IP protocol as used by ip.access",
 434                                     "GSM over IP", "gsm_ipa");
 435         proto_ipaccess =
 436             proto_register_protocol("GSM over IP ip.access CCM sub-protocol",
 437                                     "IPA", "ipaccess");
 438
 439         proto_register_field_array(proto_ipa, hf, array_length(hf));
 440         proto_register_field_array(proto_ipaccess, hf_ipa, array_length(hf_ipa));
 441         proto_register_subtree_array(ett, array_length(ett));
 442
 443         register_dissector("gsm_ipa", dissect_ipa, proto_ipa);
 444
 445         /* Register table for subdissectors */
 446         osmo_dissector_table = register_dissector_table("ipa.osmo.protocol",
 447                                         "GSM over IP ip.access Protocol",
 448                                         FT_UINT8, BASE_DEC);
 449
 450
 451         range_convert_str(&global_ipa_tcp_ports, IPA_TCP_PORTS, MAX_TCP_PORT);
 452         range_convert_str(&global_ipa_udp_ports, IPA_UDP_PORTS_DEFAULT, MAX_UDP_PORT);
 453         ipa_module = prefs_register_protocol(proto_ipa,
 454                                              proto_reg_handoff_gsm_ipa);
 455
 456         prefs_register_range_preference(ipa_module, "tcp_ports",
 457                                         "GSM IPA TCP Port(s)",
 458                                         "Set the port(s) for ip.access IPA"
 459                                         " (default: " IPA_TCP_PORTS ")",
 460                                         &global_ipa_tcp_ports, MAX_TCP_PORT);
 461         prefs_register_range_preference(ipa_module, "udp_ports",
 462                                         "GSM IPA UDP Port(s)",
 463                                         "Set the port(s) for ip.access IPA"
 464                                         " (usually: " IPA_UDP_PORTS ")",
 465                                         &global_ipa_udp_ports, MAX_UDP_PORT);
 466
 467         prefs_register_bool_preference(ipa_module, "hsl_debug_in_root_tree",
 468                                         "HSL Debug messages in root protocol tree",
 469                                         NULL, &global_ipa_in_root);
 470         prefs_register_bool_preference(ipa_module, "hsl_debug_in_info",
 471                                         "HSL Debug messages in INFO column",
 472                                         NULL, &global_ipa_in_info);
 473 }
 474
 475 void proto_reg_handoff_gsm_ipa(void)
 476 {
 477         static gboolean ipa_initialized = FALSE;
 478         static range_t *ipa_tcp_ports, *ipa_udp_ports;
 479
 480         if (!ipa_initialized) {
 481                 sub_handles[SUB_RSL] = find_dissector("gsm_abis_rsl");
 482                 sub_handles[SUB_OML] = find_dissector("gsm_abis_oml");
 483                 sub_handles[SUB_SCCP] = find_dissector("sccp");
 484                 sub_handles[SUB_MGCP] = find_dissector("mgcp");
 485                 sub_handles[SUB_DATA] = find_dissector("data");
 486
 487                 ipa_handle = create_dissector_handle(dissect_ipa, proto_ipa);
 488                 ipa_initialized = TRUE;
 489         } else {
 490                 dissector_delete_uint_range("tcp.port", ipa_tcp_ports, ipa_handle);
 491                 g_free(ipa_tcp_ports);
 492                 dissector_delete_uint_range("udp.port", ipa_udp_ports, ipa_handle);
 493                 g_free(ipa_udp_ports);
 494         }
 495
 496         ipa_tcp_ports = range_copy(global_ipa_tcp_ports);
 497         ipa_udp_ports = range_copy(global_ipa_udp_ports);
 498
 499         dissector_add_uint_range("udp.port", ipa_udp_ports, ipa_handle);
 500         dissector_add_uint_range("tcp.port", ipa_tcp_ports, ipa_handle);
 501 }