asn1/tcap/packet-tcap-template.c

   1 /* packet-tcap-template.c
   2  * Routines for  TCAP
   3  * Copyright 2004 - 2005, Tim Endean <endeant@hotmail.com>
   4  * Built from the gsm-map dissector Copyright 2004 - 2005, Anders Broman <anders.broman@ericsson.com>
   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  * References: ETSI 300 374
  26  */
  27
  28 #ifdef HAVE_CONFIG_H
  29 # include "config.h"
  30 #endif
  31
  32 #include <glib.h>
  33 #include <epan/packet.h>
  34 #include <epan/prefs.h>
  35 #include <epan/oids.h>
  36 #include <epan/asn1.h>
  37 #include <epan/strutil.h>
  38
  39 #include <string.h>
  40 #include "packet-ber.h"
  41 #include "packet-tcap.h"
  42 #include <epan/tcap-persistentdata.h>
  43
  44 #define PNAME  "Transaction Capabilities Application Part"
  45 #define PSNAME "TCAP"
  46 #define PFNAME "tcap"
  47
  48 /* Initialize the protocol and registered fields */
  49 static int proto_tcap = -1;
  50 static int hf_tcap_tag = -1;
  51 static int hf_tcap_length = -1;
  52 static int hf_tcap_data = -1;
  53 static int hf_tcap_tid = -1;
  54
  55 int hf_tcapsrt_SessionId=-1;
  56 int hf_tcapsrt_Duplicate=-1;
  57 int hf_tcapsrt_BeginSession=-1;
  58 int hf_tcapsrt_EndSession=-1;
  59 int hf_tcapsrt_SessionTime=-1;
  60
  61 #include "packet-tcap-hf.c"
  62
  63 /* Initialize the subtree pointers */
  64 static gint ett_tcap = -1;
  65 static gint ett_param = -1;
  66
  67 static gint ett_otid = -1;
  68 static gint ett_dtid = -1;
  69 gint ett_tcap_stat = -1;
  70
  71 static struct tcapsrt_info_t * gp_tcapsrt_info;
  72 static gboolean tcap_subdissector_used=FALSE;
  73 static dissector_handle_t requested_subdissector_handle = NULL;
  74
  75 static struct tcaphash_context_t * gp_tcap_context=NULL;
  76
  77 #include "packet-tcap-ett.c"
  78
  79 #define MAX_SSN 254
  80 static range_t *global_ssn_range;
  81 static range_t *ssn_range;
  82 struct tcap_private_t tcap_private;
  83
  84 gboolean gtcap_HandleSRT=FALSE;
  85 extern gboolean gtcap_PersistentSRT;
  86 extern gboolean gtcap_DisplaySRT;
  87 extern guint gtcap_RepetitionTimeout;
  88 extern guint gtcap_LostTimeout;
  89
  90 static dissector_handle_t       tcap_handle = NULL;
  91 static dissector_table_t ber_oid_dissector_table;
  92 static const char * cur_oid;
  93 static const char * tcapext_oid;
  94 static proto_tree * tcap_top_tree=NULL;
  95 static proto_tree * tcap_stat_tree=NULL;
  96
  97 static dissector_handle_t data_handle;
  98 static dissector_handle_t ansi_tcap_handle;
  99
 100 static void raz_tcap_private(struct tcap_private_t * p_tcap_private);
 101 static int dissect_tcap_param(asn1_ctx_t *actx, proto_tree *tree, tvbuff_t *tvb, int offset);
 102 static int dissect_tcap_ITU_ComponentPDU(gboolean implicit_tag _U_, tvbuff_t *tvb, int offset, asn1_ctx_t *actx _U_, proto_tree *tree, int hf_index _U_);
 103
 104 static GHashTable* ansi_sub_dissectors = NULL;
 105 static GHashTable* itu_sub_dissectors = NULL;
 106
 107 static void dissect_tcap(tvbuff_t *tvb, packet_info *pinfo, proto_tree *parent_tree);
 108
 109 extern void add_ansi_tcap_subdissector(guint32 ssn, dissector_handle_t dissector) {
 110     g_hash_table_insert(ansi_sub_dissectors,GUINT_TO_POINTER(ssn),dissector);
 111     dissector_add("sccp.ssn",ssn,tcap_handle);
 112 }
 113
 114 extern void add_itu_tcap_subdissector(guint32 ssn, dissector_handle_t dissector) {
 115     g_hash_table_insert(itu_sub_dissectors,GUINT_TO_POINTER(ssn),dissector);
 116     dissector_add("sccp.ssn",ssn,tcap_handle);
 117 }
 118
 119 extern void delete_ansi_tcap_subdissector(guint32 ssn, dissector_handle_t dissector _U_) {
 120     g_hash_table_remove(ansi_sub_dissectors,GUINT_TO_POINTER(ssn));
 121     if (!get_itu_tcap_subdissector(ssn))
 122       dissector_delete("sccp.ssn",ssn,tcap_handle);
 123 }
 124 extern void delete_itu_tcap_subdissector(guint32 ssn, dissector_handle_t dissector _U_) {
 125     g_hash_table_remove(itu_sub_dissectors,GUINT_TO_POINTER(ssn));
 126     if (!get_ansi_tcap_subdissector(ssn))
 127       dissector_delete("sccp.ssn", ssn,tcap_handle);
 128 }
 129
 130 dissector_handle_t get_ansi_tcap_subdissector(guint32 ssn) {
 131     return g_hash_table_lookup(ansi_sub_dissectors,GUINT_TO_POINTER(ssn));
 132 }
 133
 134 dissector_handle_t get_itu_tcap_subdissector(guint32 ssn) {
 135     return g_hash_table_lookup(itu_sub_dissectors,GUINT_TO_POINTER(ssn));
 136 }
 137
 138
 139
 140 #include "packet-tcap-fn.c"
 141
 142
 143
 144 const value_string tcap_component_type_str[] = {
 145     { TCAP_COMP_INVOKE,         "Invoke" },
 146     { TCAP_COMP_RRL,            "Return Result(L)" },
 147     { TCAP_COMP_RE,                     "Return Error" },
 148     { TCAP_COMP_REJECT,         "Reject" },
 149     { TCAP_COMP_RRN,            "Return Result(NL)" },
 150     { 0,                        NULL } };
 151
 152
 153 static void
 154 dissect_tcap(tvbuff_t *tvb, packet_info *pinfo, proto_tree *parent_tree)
 155 {
 156     proto_item          *item=NULL;
 157     proto_tree          *tree=NULL;
 158
 159     struct tcaphash_context_t * p_tcap_context;
 160     dissector_handle_t subdissector_handle;
 161         asn1_ctx_t asn1_ctx;
 162         gint8 class;
 163         gboolean pc;
 164         gint tag;
 165
 166         /* Check if ANSI TCAP and call the ANSI TCAP dissector if that's the case
 167          * PackageType ::= CHOICE { unidirectional                      [PRIVATE 1] IMPLICIT UniTransactionPDU,
 168          *                                               queryWithPerm                          [PRIVATE 2] IMPLICIT TransactionPDU,
 169          *                                               queryWithoutPerm                       [PRIVATE 3] IMPLICIT TransactionPDU,
 170          *                                               response                                       [PRIVATE 4] IMPLICIT TransactionPDU,
 171          *                                               conversationWithPerm           [PRIVATE 5] IMPLICIT TransactionPDU,
 172          *                                               conversationWithoutPerm        [PRIVATE 6] IMPLICIT TransactionPDU,
 173          *                                               abort                                          [PRIVATE 22] IMPLICIT Abort
 174          *                                               }
 175          *
 176          *
 177          */
 178         get_ber_identifier(tvb, 0, &class, &pc, &tag);
 179
 180         if(class == BER_CLASS_PRI){
 181                 switch(tag){
 182                 case 1:
 183                 case 2:
 184                 case 3:
 185                 case 4:
 186                 case 5:
 187                 case 6:
 188                 case 22:
 189                         call_dissector(ansi_tcap_handle, tvb, pinfo, parent_tree);
 190                         return;
 191                         break;
 192                 default:
 193                         return;
 194                 }
 195         }
 196
 197         /* ITU TCAP */
 198         asn1_ctx_init(&asn1_ctx, ASN1_ENC_BER, TRUE, pinfo);
 199
 200     tcap_top_tree = parent_tree;
 201     tcap_stat_tree = NULL;
 202
 203     col_set_str(pinfo->cinfo, COL_PROTOCOL, "TCAP");
 204
 205     /* create display subtree for the protocol */
 206     if(parent_tree){
 207       item = proto_tree_add_item(parent_tree, proto_tcap, tvb, 0, -1, FALSE);
 208       tree = proto_item_add_subtree(item, ett_tcap);
 209       tcap_stat_tree=tree;
 210     }
 211     cur_oid = NULL;
 212     tcapext_oid = NULL;
 213     raz_tcap_private(&tcap_private);
 214
 215     pinfo->private_data = &tcap_private;
 216     gp_tcapsrt_info=tcapsrt_razinfo();
 217     tcap_subdissector_used=FALSE;
 218     gp_tcap_context=NULL;
 219     dissect_tcap_TCMessage(FALSE, tvb, 0, &asn1_ctx, tree, -1);
 220
 221     if (gtcap_HandleSRT && !tcap_subdissector_used ) {
 222       p_tcap_context=tcapsrt_call_matching(tvb, pinfo, tcap_stat_tree, gp_tcapsrt_info);
 223       tcap_private.context=p_tcap_context;
 224
 225                 /* If the current message is TCAP only,
 226                  * save the Application Context Name for the next messages
 227                  */
 228                 if ( p_tcap_context && cur_oid && !p_tcap_context->oid_present ) {
 229                         /* Save the application context and the sub dissector */
 230                         g_strlcpy(p_tcap_context->oid,cur_oid, LENGTH_OID);
 231                         p_tcap_context->oid_present=TRUE;
 232                         if ( (subdissector_handle = dissector_get_string_handle(ber_oid_dissector_table, cur_oid)) ) {
 233                                 p_tcap_context->subdissector_handle=subdissector_handle;
 234                                 p_tcap_context->subdissector_present=TRUE;
 235                         }
 236                 }
 237                 if (gtcap_HandleSRT && p_tcap_context && p_tcap_context->callback) {
 238                         /* Callback fonction for the upper layer */
 239                         (p_tcap_context->callback)(tvb, pinfo, tcap_stat_tree, p_tcap_context);
 240                 }
 241         }
 242 }
 243
 244 void
 245 proto_reg_handoff_tcap(void)
 246 {
 247
 248     data_handle = find_dissector("data");
 249     ansi_tcap_handle = find_dissector("ansi_tcap");
 250     ber_oid_dissector_table = find_dissector_table("ber.oid");
 251
 252 #include "packet-tcap-dis-tab.c"
 253 }
 254
 255 static void init_tcap(void);
 256
 257 void
 258 proto_register_tcap(void)
 259 {
 260
 261 /* Setup list of header fields  See Section 1.6.1 for details*/
 262     static hf_register_info hf[] = {
 263         { &hf_tcap_tag,
 264                 { "Tag",           "tcap.msgtype",
 265                 FT_UINT8, BASE_HEX, NULL, 0,
 266                 NULL, HFILL }
 267         },
 268         { &hf_tcap_length,
 269                 { "Length", "tcap.len",
 270                 FT_UINT8, BASE_DEC, NULL, 0,
 271                 NULL, HFILL }
 272         },
 273         { &hf_tcap_data,
 274                 { "Data", "tcap.data",
 275                 FT_BYTES, BASE_NONE, NULL, 0,
 276                 NULL, HFILL }
 277         },
 278                 { &hf_tcap_tid,
 279                 { "Transaction Id", "tcap.tid",
 280                 FT_BYTES, BASE_NONE, NULL, 0,
 281                 NULL, HFILL }
 282         },
 283         /* Tcap Service Response Time */
 284         { &hf_tcapsrt_SessionId,
 285           { "Session Id",
 286             "tcap.srt.session_id",
 287             FT_UINT32, BASE_DEC, NULL, 0x0,
 288             NULL, HFILL }
 289         },
 290         { &hf_tcapsrt_BeginSession,
 291           { "Begin Session",
 292             "tcap.srt.begin",
 293             FT_FRAMENUM, BASE_NONE, NULL, 0x0,
 294             "SRT Begin of Session", HFILL }
 295         },
 296         { &hf_tcapsrt_EndSession,
 297           { "End Session",
 298             "tcap.srt.end",
 299             FT_FRAMENUM, BASE_NONE, NULL, 0x0,
 300             "SRT End of Session", HFILL }
 301         },
 302         { &hf_tcapsrt_SessionTime,
 303           { "Session duration",
 304             "tcap.srt.sessiontime",
 305             FT_RELATIVE_TIME, BASE_NONE, NULL, 0x0,
 306             "Duration of the TCAP session", HFILL }
 307         },
 308         { &hf_tcapsrt_Duplicate,
 309           { "Session Duplicate",
 310             "tcap.srt.duplicate",
 311             FT_FRAMENUM, BASE_NONE, NULL, 0x0,
 312             "SRT Duplicated with Session", HFILL }
 313         },
 314 #include "packet-tcap-hfarr.c"
 315     };
 316
 317 /* Setup protocol subtree array */
 318     static gint *ett[] = {
 319         &ett_tcap,
 320         &ett_param,
 321         &ett_otid,
 322         &ett_dtid,
 323         &ett_tcap_stat,
 324         #include "packet-tcap-ettarr.c"
 325     };
 326
 327     /*static enum_val_t tcap_options[] = {
 328         { "itu", "ITU",  ITU_TCAP_STANDARD },
 329         { "ansi", "ANSI", ANSI_TCAP_STANDARD },
 330         { NULL, NULL, 0 }
 331     };*/
 332
 333     module_t *tcap_module;
 334
 335 /* Register the protocol name and description */
 336     proto_tcap = proto_register_protocol(PNAME, PSNAME, PFNAME);
 337
 338 /* Required function calls to register the header fields and subtrees used */
 339     proto_register_field_array(proto_tcap, hf, array_length(hf));
 340     proto_register_subtree_array(ett, array_length(ett));
 341
 342     tcap_module = prefs_register_protocol(proto_tcap, NULL);
 343
 344 #if 0
 345     prefs_register_enum_preference(tcap_module, "standard", "ITU TCAP standard",
 346         "The SS7 standard used in ITU TCAP packets",
 347         &tcap_standard, tcap_options, FALSE);
 348 #else
 349     prefs_register_obsolete_preference(tcap_module, "standard");
 350 #endif
 351
 352 #if 0
 353     prefs_register_bool_preference(tcap_module, "lock_info_col", "Lock Info column",
 354         "Always show TCAP in Info column",
 355         &lock_info_col);
 356 #else
 357     prefs_register_obsolete_preference(tcap_module, "lock_info_col");
 358 #endif
 359
 360     /* Set default SSNs */
 361     range_convert_str(&global_ssn_range, "", MAX_SSN);
 362     ssn_range = range_empty();
 363
 364     prefs_register_range_preference(tcap_module, "ssn", "SCCP SSNs",
 365         "SCCP (and SUA) SSNs to decode as TCAP",
 366         &global_ssn_range, MAX_SSN);
 367
 368     prefs_register_bool_preference(tcap_module, "srt",
 369                                    "Service Response Time Analyse",
 370                                    "Activate the analyse for Response Time",
 371                                    &gtcap_HandleSRT);
 372
 373     prefs_register_bool_preference(tcap_module, "persistentsrt",
 374                                    "Persistent stats for SRT",
 375                                    "Statistics for Response Time",
 376                                    &gtcap_PersistentSRT);
 377
 378     prefs_register_uint_preference(tcap_module, "repetitiontimeout",
 379                                    "Repetition timeout",
 380                                    "Maximal delay for message repetion",
 381                                    10, &gtcap_RepetitionTimeout);
 382
 383     prefs_register_uint_preference(tcap_module, "losttimeout",
 384                                    "lost timeout",
 385                                    "Maximal delay for message lost",
 386                                    10, &gtcap_LostTimeout);
 387
 388     ansi_sub_dissectors = g_hash_table_new(g_direct_hash,g_direct_equal);
 389     itu_sub_dissectors = g_hash_table_new(g_direct_hash,g_direct_equal);
 390
 391     /* 'globally' register dissector */
 392     register_dissector("tcap", dissect_tcap, proto_tcap);
 393
 394     tcap_handle = create_dissector_handle(dissect_tcap, proto_tcap);
 395
 396     register_init_routine(&init_tcap);
 397 }
 398
 399
 400 static void range_delete_callback(guint32 ssn)
 401 {
 402     if ( ssn && !get_ansi_tcap_subdissector(ssn) && !get_itu_tcap_subdissector(ssn) ) {
 403         dissector_delete("sccp.ssn", ssn, tcap_handle);
 404     }
 405 }
 406
 407 static void range_add_callback(guint32 ssn)
 408 {
 409     if (ssn && !get_ansi_tcap_subdissector(ssn) && !get_itu_tcap_subdissector(ssn) ) {
 410         dissector_add("sccp.ssn", ssn, tcap_handle);
 411     }
 412 }
 413
 414
 415 static void init_tcap(void) {
 416     if (ssn_range) {
 417         range_foreach(ssn_range, range_delete_callback);
 418         g_free(ssn_range);
 419     }
 420
 421     ssn_range = range_copy(global_ssn_range);
 422     range_foreach(ssn_range, range_add_callback);
 423     tcapsrt_init_routine();
 424 }
 425
 426 static int
 427 dissect_tcap_param(asn1_ctx_t *actx, proto_tree *tree, tvbuff_t *tvb, int offset)
 428 {
 429     gint tag_offset, saved_offset, len_offset;
 430     tvbuff_t    *next_tvb;
 431     proto_tree *subtree;
 432     proto_item *pi;
 433     gint8 class;
 434     gboolean pc;
 435     gint32 tag;
 436     guint32 len;
 437     guint32 tag_length;
 438     guint32 len_length;
 439     gboolean ind_field;
 440
 441     while (tvb_reported_length_remaining(tvb, offset) > 0)
 442     {
 443         saved_offset = offset;
 444
 445         offset = get_ber_identifier(tvb, offset, &class, &pc, &tag);
 446         tag_offset = offset;
 447         offset = get_ber_length(tvb, offset, &len, &ind_field);
 448         len_offset = offset;
 449
 450         tag_length = tag_offset - saved_offset;
 451         len_length = len_offset - tag_offset;
 452
 453         if (pc)
 454         {
 455             pi = proto_tree_add_text(tree, tvb, saved_offset,
 456                                      len + (len_offset - saved_offset),
 457                                      "CONSTRUCTOR");
 458             subtree = proto_item_add_subtree(pi, ett_param);
 459             proto_tree_add_uint_format(subtree, hf_tcap_tag, tvb,
 460                                        saved_offset, tag_length, tag,
 461                                        "CONSTRUCTOR Tag");
 462             proto_tree_add_uint(subtree, hf_tcap_tag, tvb, saved_offset,
 463                                 tag_length, class);
 464
 465             proto_tree_add_uint(subtree, hf_tcap_length, tvb, tag_offset,
 466                                 len_length, len);
 467
 468             if (len-(2*ind_field)) /*should always be positive unless we get an empty contructor pointless? */
 469             {
 470                 next_tvb = tvb_new_subset(tvb, offset, len-(2*ind_field),
 471                                           len-(2*ind_field));
 472                 dissect_tcap_param(actx, subtree,next_tvb,0);
 473             }
 474
 475             if (ind_field)
 476                     proto_tree_add_text(subtree, tvb, offset+len-2, 2, "CONSTRUCTOR EOC");
 477
 478             offset += len;
 479         }
 480         else
 481         {
 482             pi = proto_tree_add_text(tree, tvb, saved_offset,
 483                                      len + (len_offset - saved_offset),
 484                                      "Parameter (0x%.2x)", tag);
 485
 486             subtree = proto_item_add_subtree(pi, ett_param);
 487
 488             proto_tree_add_uint(subtree, hf_tcap_tag, tvb, saved_offset,
 489                                 tag_length, tag);
 490
 491             proto_tree_add_uint(subtree, hf_tcap_length, tvb,
 492                                 saved_offset+tag_length, len_length, len);
 493
 494             if (len) /* check for NULLS */
 495             {
 496                 next_tvb = tvb_new_subset(tvb, offset, len, len);
 497                 dissect_ber_octet_string(TRUE, actx, tree, next_tvb, 0,
 498                                          hf_tcap_data, NULL);
 499             }
 500
 501             offset += len;
 502         }
 503     }
 504     return offset;
 505 }
 506
 507 static void raz_tcap_private(struct tcap_private_t * p_tcap_private)
 508 {
 509   memset(p_tcap_private,0,sizeof(struct tcap_private_t) );
 510 }
 511
 512 /*
 513  * Call ITU Subdissector to decode the Tcap Component
 514  */
 515 static int
 516 dissect_tcap_ITU_ComponentPDU(gboolean implicit_tag _U_, tvbuff_t *tvb, int offset, asn1_ctx_t *actx _U_, proto_tree *tree, int hf_index _U_)
 517 {
 518   dissector_handle_t subdissector_handle=NULL;
 519   gboolean is_subdissector=FALSE;
 520   struct tcaphash_context_t * p_tcap_context=NULL;
 521
 522   /*
 523    * ok lets look at the oid and ssn and try and find a dissector, otherwise lets decode it.
 524    */
 525
 526   /*
 527    * Handle The TCAP Service Response Time
 528    */
 529   if ( gtcap_HandleSRT ) {
 530           if (!tcap_subdissector_used) {
 531             p_tcap_context=tcapsrt_call_matching(tvb, actx->pinfo, tcap_stat_tree, gp_tcapsrt_info);
 532             tcap_subdissector_used=TRUE;
 533             gp_tcap_context=p_tcap_context;
 534             tcap_private.context=p_tcap_context;
 535           }else{
 536                   /* Take the last TCAP context */
 537                   p_tcap_context = gp_tcap_context;
 538                   tcap_private.context=p_tcap_context;
 539           }
 540   }
 541   if (p_tcap_context) {
 542           if (cur_oid) {
 543                   if (p_tcap_context->oid_present) {
 544                           /* We have already an Application Context, check if we have
 545                              to fallback to a lower version */
 546                           if ( strncmp(p_tcap_context->oid,cur_oid, LENGTH_OID)!=0) {
 547                                   /* ACN, changed, Fallback to lower version
 548                                    * and update the subdissector (purely formal)
 549                                    */
 550                                   g_strlcpy(p_tcap_context->oid,cur_oid, LENGTH_OID);
 551                                   if ( (subdissector_handle = dissector_get_string_handle(ber_oid_dissector_table, cur_oid)) ) {
 552                                           p_tcap_context->subdissector_handle=subdissector_handle;
 553                                           p_tcap_context->subdissector_present=TRUE;
 554                                   }
 555                           }
 556                   } else {
 557                           /* We do not have the OID in the TCAP context, so store it */
 558                           g_strlcpy(p_tcap_context->oid,cur_oid, LENGTH_OID);
 559                           p_tcap_context->oid_present=TRUE;
 560                           /* Try to find a subdissector according to OID */
 561                           if ( (subdissector_handle
 562                                   = dissector_get_string_handle(ber_oid_dissector_table, cur_oid)) ) {
 563                                   p_tcap_context->subdissector_handle=subdissector_handle;
 564                                   p_tcap_context->subdissector_present=TRUE;
 565                           } else {
 566                             /* Not found, so try to find a subdissector according to SSN */
 567                             if ( (subdissector_handle = get_itu_tcap_subdissector(actx->pinfo->match_port))) {
 568                               /* Found according to SSN */
 569                               p_tcap_context->subdissector_handle=subdissector_handle;
 570                               p_tcap_context->subdissector_present=TRUE;
 571                             }
 572                           }
 573                   } /* context OID */
 574           } else {
 575                   /* Copy the OID from the TCAP context to the current oid */
 576                   if (p_tcap_context->oid_present) {
 577                           tcap_private.oid= (void*) p_tcap_context->oid;
 578                           tcap_private.acv=TRUE;
 579                   }
 580           } /* no OID */
 581   } /* no TCAP context */
 582
 583
 584   if ( p_tcap_context
 585        && p_tcap_context->subdissector_present) {
 586     /* Take the subdissector from the context */
 587     subdissector_handle=p_tcap_context->subdissector_handle;
 588     is_subdissector=TRUE;
 589   }
 590
 591   /* Have SccpUsersTable protocol taking precedence over sccp.ssn table */
 592   if (!is_subdissector && requested_subdissector_handle) {
 593           is_subdissector = TRUE;
 594           subdissector_handle = requested_subdissector_handle;
 595   }
 596
 597   if (!is_subdissector) {
 598     /*
 599      * If we do not currently know the subdissector, we have to find it
 600      * - first, according to the OID
 601      * - then according to the SSN
 602      * - and at least, take the default Data handler
 603      */
 604     if (ber_oid_dissector_table && cur_oid) {
 605       /* Search if we can find the sub protocol according to the A.C.N */
 606       if ( (subdissector_handle
 607             = dissector_get_string_handle(ber_oid_dissector_table, cur_oid)) ) {
 608                   /* found */
 609                   is_subdissector=TRUE;
 610       } else {
 611                   /* Search if we can found the sub protocol according to the SSN table */
 612                   if ( (subdissector_handle
 613                           = get_itu_tcap_subdissector(actx->pinfo->match_port))) {
 614                           /* Found according to SSN */
 615                           is_subdissector=TRUE;
 616                   } else {
 617                           /* Nothing found, take the Data handler */
 618                           subdissector_handle = data_handle;
 619                           is_subdissector=TRUE;
 620                   } /* SSN */
 621           } /* ACN */
 622         } else {
 623                 /* There is no A.C.N for this transaction, so search in the SSN table */
 624                 if ( (subdissector_handle = get_itu_tcap_subdissector(actx->pinfo->match_port))) {
 625                         /* Found according to SSN */
 626                         is_subdissector=TRUE;
 627                 } else {
 628                         subdissector_handle = data_handle;
 629                         is_subdissector=TRUE;
 630                 }
 631         } /* OID */
 632   } else {
 633           /* We have it already */
 634   }
 635
 636   /* Call the sub dissector if present, and not already called */
 637   if (is_subdissector)
 638     call_dissector(subdissector_handle, tvb, actx->pinfo, tree);
 639
 640   return offset;
 641 }
 642
 643 void call_tcap_dissector(dissector_handle_t handle, tvbuff_t* tvb, packet_info* pinfo, proto_tree* tree) {
 644
 645         requested_subdissector_handle = handle;
 646
 647         TRY {
 648                 dissect_tcap(tvb, pinfo, tree);
 649         } CATCH_ALL {
 650                 requested_subdissector_handle = NULL;
 651                 RETHROW;
 652         } ENDTRY;
 653
 654         requested_subdissector_handle = NULL;
 655
 656 }
 657
 658