asn1/atn-cpdlc/packet-atn-cpdlc-template.c

   1 /* c-basic-offset: 2; tab-width: 2; indent-tabs-mode: t
   2  * vi: set shiftwidth=2 tabstop=2 noexpandtab:
   3  * :indentSize=2:tabSize=2:noTabs=false:
   4  */
   5
   6 /* packet-atn-cpdlc-template.c
   7  * By Mathias Guettler <guettler@web.de>
   8  * Copyright 2013
   9  *
  10  * Routines for ATN Cpdlcc protocol packet disassembly
  11
  12  * details see:
  13  * http://en.wikipedia.org/wiki/CPDLC
  14  * http://members.optusnet.com.au/~cjr/introduction.htm
  15
  16  * standards:
  17  * http://legacy.icao.int/anb/panels/acp/repository.cfm
  18
  19  * note:
  20  * We are dealing with ATN/CPDLC aka ICAO Doc 9705 Ed2 here
  21  * (CPDLC may also be transmitted via ACARS/AOA aka "FANS-1/A ").
  22
  23  *
  24  * Wireshark - Network traffic analyzer
  25  * By Gerald Combs <gerald@wireshark.org>
  26  * Copyright 1998 Gerald Combs
  27  *
  28  * This program is free software; you can redistribute it and/or
  29  * modify it under the terms of the GNU General Public License
  30  * as published by the Free Software Foundation; either version 2
  31  * of the License, or (at your option) any later version.
  32  *
  33  * This program is distributed in the hope that it will be useful,
  34  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  35  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  36  * GNU General Public License for more details.
  37  *
  38  * You should have received a copy of the GNU General Public License
  39  * along with this program; if not, write to the Free Software
  40  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  41  */
  42
  43 /*
  44  developper comments:
  45         Which CPDLC messages are supported ?
  46                 Protected Mode CPDLC (AeQualifier 22) and Plain Old CPDLC (AeQualifier 2)
  47                 The dissector has been tested with ICAO doc9705 Edition2 compliant traffic.
  48 */
  49
  50 #include "config.h"
  51
  52 #include <glib.h>
  53 #include <epan/packet.h>
  54 #include <epan/exceptions.h>
  55 #include <epan/conversation.h>
  56 #include <epan/dissectors/packet-ber.h>
  57 #include <epan/dissectors/packet-per.h>
  58
  59 #include <stdio.h>
  60 #include <string.h>
  61
  62 #include "packet-atn-ulcs.h"
  63
  64 #define ATN_CPDLC_PROTO "ICAO Doc9705 CPDLC"
  65
  66 void proto_register_atn_cpdlc(void);
  67 void proto_reg_handoff_atn_cpdlc(void);
  68
  69 static const char *object_identifier_id;
  70
  71 /* forward declarations */
  72 static void dissect_GroundPDUs_PDU(
  73                 tvbuff_t *tvb _U_,
  74                 packet_info *pinfo _U_,
  75                 proto_tree *tree _U_);
  76 static void dissect_AircraftPDUs_PDU(
  77                 tvbuff_t *tvb _U_,
  78                 packet_info *pinfo _U_,
  79                 proto_tree *tree _U_);
  80 static void dissect_ProtectedGroundPDUs_PDU(
  81                 tvbuff_t *tvb _U_,
  82                 packet_info *pinfo _U_,
  83                 proto_tree *tree _U_);
  84 static void dissect_ProtectedAircraftPDUs_PDU(
  85                 tvbuff_t *tvb _U_,
  86                 packet_info *pinfo _U_,
  87                 proto_tree *tree _U_);
  88
  89 #include "packet-atn-cpdlc-hf.c"
  90
  91 #include "packet-atn-cpdlc-ett.c"
  92 static gint ett_atn_cpdlc = -1;
  93
  94 #include "packet-atn-cpdlc-fn.c"
  95
  96 /* Wireshark ID of CPDLC protocol */
  97 static int proto_atn_cpdlc = -1;
  98
  99
 100 static int
 101 dissect_atn_cpdlc(
 102                 tvbuff_t *tvb,
 103                 packet_info *pinfo,
 104                 proto_tree *tree,
 105                 void *data _U_)
 106 {
 107                 /* note: */
 108                 /* there are two co-existing applications of CPDLC: */
 109                 /* "plain old" (ae-qualifier 2) and */
 110                 /* "protected mode" (ae-qualifier 22) CPDLC. */
 111                 /* "protected mode" was introduced to cope with a */
 112                 /* safety issue in which a message would sent to the wrong aircraft. */
 113
 114                 /* note:*/
 115                 /* The protection is an additional checksum and covers the message content, */
 116                 /* the 24-bit address of the aircraft, the current flight id and */
 117                 /* the current ground facility so that an aircraft would be able to reject */
 118                 /* messages which are unexpected (i.e. messages to another flight or */
 119                 /* messages from the wrong center). */
 120
 121                 /*note:*/
 122                 /* although "plain old" CPDLC is more or less deprecated */
 123                 /* many aircraft cannot perform  */
 124                 /* "protected mode" for this largely depends on */
 125                 /* upgraded avionics packages */
 126
 127                 /*note:*/
 128                 /* The use of CPDLC is *optional* as the pilot  */
 129                 /* may always use a voice radio channel to talk to the controller.*/
 130
 131                 proto_item *ti = NULL;
 132                 proto_tree *atn_cpdlc_tree = NULL;
 133                 atn_conversation_t *atn_cv = NULL;
 134
 135                 /* note: */
 136                 /* we need the ae qualifier stored within the conversation */
 137                 /* to decode "plain old cpdlc" or  */
 138                 /* "protected mode cpdlc correctly " */
 139
 140                 /* DT: dstref present, srcref is always zero */
 141                 if((pinfo->clnp_dstref) && (!pinfo->clnp_srcref)){
 142                                 atn_cv = find_atn_conversation(
 143                                                 &pinfo->dst,
 144                                                 pinfo->clnp_dstref,
 145                                                 &pinfo->src );
 146                 }
 147                 /* CR: srcref present, dstref is always zero */
 148                 if((!pinfo->clnp_dstref) && (pinfo->clnp_srcref)){
 149                                 atn_cv = find_atn_conversation(
 150                                                 &pinfo->src,
 151                                                 pinfo->clnp_srcref,
 152                                                 &pinfo->dst );
 153                 }
 154                 /* CC: srcref and dstref present, always use src/srcref & dst */
 155                 if((pinfo->clnp_dstref) && (pinfo->clnp_srcref)){
 156                                 atn_cv = find_atn_conversation(
 157                                                 &pinfo->src,
 158                                                 pinfo->clnp_srcref,
 159                                                 &pinfo->dst );
 160                 }
 161
 162                 if(!atn_cv){ /* atn conversation not found */
 163                         return 0; }
 164
 165                 ti = proto_tree_add_text(
 166                                 tree,
 167                                 tvb,
 168                                 0,
 169                                 tvb_reported_length_remaining(tvb, 0) ,
 170                                 ATN_CPDLC_PROTO );
 171
 172                 atn_cpdlc_tree = proto_item_add_subtree(
 173                                 ti,
 174                                 ett_atn_cpdlc);
 175
 176                 switch(atn_cv->ae_qualifier){
 177                                 case  pmcpdlc:
 178                                                 if( check_heur_msg_type(pinfo) == um ) {
 179                                                                 /* uplink PDU's = Ground PDU's */
 180                                                                 dissect_ProtectedGroundPDUs_PDU(
 181                                                                                 tvb,
 182                                                                                 pinfo,
 183                                                                                 atn_cpdlc_tree);
 184                                                 }else {  /* downlink PDU's = Aircraft PDU's */
 185                                                                 dissect_ProtectedAircraftPDUs_PDU(
 186                                                                                 tvb,
 187                                                                                 pinfo,
 188                                                                         atn_cpdlc_tree);
 189                                                 }
 190                                                 break;
 191                                 case cpdlc:
 192                                                 if( check_heur_msg_type(pinfo) == um ) {
 193                                                                 /* uplink PDU's = Ground PDU's */
 194                                                                 dissect_GroundPDUs_PDU(
 195                                                                                 tvb,
 196                                                                                 pinfo,
 197                                                                                 atn_cpdlc_tree);
 198                                                 }else {  /* downlink PDU's = Aircraft PDU's */
 199                                                                 dissect_AircraftPDUs_PDU(
 200                                                                                 tvb,
 201                                                                                 pinfo,
 202                                                                                 atn_cpdlc_tree);
 203                                                 }
 204                                                 break;
 205                                 default:
 206                                                 break;
 207                 }
 208                 return tvb_reported_length_remaining(tvb, 0);
 209 }
 210
 211 static gboolean
 212 dissect_atn_cpdlc_heur(
 213                 tvbuff_t *tvb,
 214                 packet_info *pinfo,
 215                 proto_tree *tree,
 216                 void *data _U_)
 217 {
 218                 atn_conversation_t *atn_cv = NULL;
 219                 volatile gboolean is_atn_cpdlc = FALSE;
 220                 volatile gboolean is_pm = FALSE;
 221                 int type;
 222
 223                 type = check_heur_msg_type(pinfo);
 224
 225                 switch(type){
 226                         case um:
 227                                         TRY {
 228                                                 dissect_ProtectedGroundPDUs_PDU(tvb, pinfo, NULL);
 229                                                 is_atn_cpdlc = TRUE;
 230                                                 is_pm = TRUE;
 231                                                 break;}
 232                                         CATCH_ALL{
 233                                                 is_atn_cpdlc = FALSE;
 234                                                 is_pm = FALSE;}
 235                                         ENDTRY;
 236                                         TRY {
 237                         dissect_GroundPDUs_PDU(tvb, pinfo, NULL);
 238                                                 is_pm = FALSE;
 239                                                 is_atn_cpdlc = TRUE;
 240                                                 break;}
 241                                         CATCH_ALL{
 242                                                 is_atn_cpdlc = FALSE;
 243                                                 is_pm = FALSE;}
 244                                         ENDTRY;
 245                                 break;
 246                 case dm:
 247                                         TRY {
 248                                                 dissect_ProtectedAircraftPDUs_PDU(tvb, pinfo, NULL);
 249                                                 is_atn_cpdlc = TRUE;
 250                                                 is_pm = TRUE;
 251                                                 break;}
 252                                         CATCH_ALL {
 253                                                 is_atn_cpdlc = FALSE;
 254                                                 is_pm = FALSE; }
 255                                         ENDTRY;
 256                                         TRY{
 257                                                 dissect_AircraftPDUs_PDU(tvb, pinfo, NULL);
 258                                                 is_atn_cpdlc = TRUE;
 259                                                 is_pm = FALSE;
 260                                                 break;}
 261                                         CATCH_ALL{
 262                                                 is_atn_cpdlc = FALSE;
 263                                                 is_pm = FALSE;}
 264                                         ENDTRY;
 265                         break;
 266                 default:
 267                         break;
 268         }
 269
 270         if(is_atn_cpdlc){
 271                 /* note: */
 272                 /* all subsequent PDU's belonging to this conversation */
 273                 /* are considered CPDLC */
 274                 /* if the first CPDLC PDU has been decoded succesfully */
 275                 /* (This is done in "atn-ulcs" by using "call_dissector_with_data()") */
 276
 277                 /* DT: dstref present, srcref is always zero */
 278                 if((pinfo->clnp_dstref) && (!pinfo->clnp_srcref)){
 279                                 atn_cv = find_atn_conversation(&pinfo->dst,
 280                                                                                                         pinfo->clnp_dstref,
 281                                                                                                         &pinfo->src );
 282                 }
 283                 /* CR: srcref present, dstref is always zero */
 284                 if((!pinfo->clnp_dstref) && (pinfo->clnp_srcref)){
 285                                 atn_cv = find_atn_conversation(&pinfo->src,
 286                                                                                                         pinfo->clnp_srcref,
 287                                                                                                         &pinfo->dst );
 288                 }
 289                 /* CC: srcref and dstref present, always use src/srcref & dst */
 290                 if((pinfo->clnp_dstref) && (pinfo->clnp_srcref)){
 291                                 atn_cv = find_atn_conversation(&pinfo->src,
 292                                                                                                         pinfo->clnp_srcref,
 293                                                                                                         &pinfo->dst );
 294                 }
 295
 296                 if(atn_cv){ /* atn conversation found */
 297                         if(is_pm == TRUE) {
 298                                 atn_cv->ae_qualifier =  pmcpdlc; }
 299                         else {
 300                                 atn_cv->ae_qualifier =  cpdlc; }
 301                         dissect_atn_cpdlc(tvb, pinfo, tree, NULL);
 302                 }
 303         }else { /* there should *always* be an atn conversation */
 304                 is_atn_cpdlc = FALSE;
 305         }
 306
 307         return is_atn_cpdlc;
 308 }
 309
 310
 311
 312 void proto_register_atn_cpdlc (void)
 313 {
 314     static hf_register_info hf_atn_cpdlc[] = {
 315                                 #include "packet-atn-cpdlc-hfarr.c"
 316                         };
 317
 318                 static gint *ett[] = {
 319                                 #include "packet-atn-cpdlc-ettarr.c"
 320                                 &ett_atn_cpdlc
 321                 };
 322
 323                 /* register CPDLC */
 324                 proto_atn_cpdlc = proto_register_protocol(
 325                                 ATN_CPDLC_PROTO ,
 326                                 "ATN-CPDLC",
 327                                 "atn-cpdlc");
 328
 329                 proto_register_field_array(
 330                                 proto_atn_cpdlc,
 331                                 hf_atn_cpdlc,
 332                                 array_length(hf_atn_cpdlc));
 333
 334                 proto_register_subtree_array(
 335                                 ett,
 336                                 array_length(ett));
 337
 338                 new_register_dissector(
 339                                 "atn-cpdlc",
 340                                 dissect_atn_cpdlc,
 341                                 proto_atn_cpdlc);
 342 }
 343
 344 void proto_reg_handoff_atn_cpdlc(void)
 345 {
 346                 /* add session dissector to atn dissector list dissector list*/
 347                 heur_dissector_add(
 348                                 "atn-ulcs",
 349                                 dissect_atn_cpdlc_heur,
 350                                 proto_atn_cpdlc);
 351 }
 352
 353
 354 /*
 355  * Editor modelines  -  http://www.wireshark.org/tools/modelines.html
 356  *
 357  * Local variables:
 358  * c-basic-offset: 2
 359  * tab-width: 2
 360  * indent-tabs-mode: t
 361  * End:
 362  *
 363  * vi: set shiftwidth=2 tabstop=2 noexpandtab:
 364  * :indentSize=2:tabSize=2:noTabs=false:
 365  */