/* c-basic-offset: 2; tab-width: 2; indent-tabs-mode: t * vi: set shiftwidth=2 tabstop=2 noexpandtab: * :indentSize=2:tabSize=2:noTabs=false: */ /* packet-atn-cpdlc-template.c * By Mathias Guettler * Copyright 2013 * * Routines for ATN Cpdlcc protocol packet disassembly * details see: * http://en.wikipedia.org/wiki/CPDLC * http://members.optusnet.com.au/~cjr/introduction.htm * standards: * http://legacy.icao.int/anb/panels/acp/repository.cfm * note: * We are dealing with ATN/CPDLC aka ICAO Doc 9705 Ed2 here * (CPDLC may also be transmitted via ACARS/AOA aka "FANS-1/A "). * * Wireshark - Network traffic analyzer * By Gerald Combs * Copyright 1998 Gerald Combs * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version 2 * of the License, or (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. */ /* developper comments: Which CPDLC messages are supported ? Protected Mode CPDLC (AeQualifier 22) and Plain Old CPDLC (AeQualifier 2) The dissector has been tested with ICAO doc9705 Edition2 compliant traffic. */ #include "config.h" #include #include #include #include #include #include #include #include #include "packet-atn-ulcs.h" #define ATN_CPDLC_PROTO "ICAO Doc9705 CPDLC" void proto_register_atn_cpdlc(void); void proto_reg_handoff_atn_cpdlc(void); static const char *object_identifier_id; /* forward declarations */ static int dissect_GroundPDUs_PDU( tvbuff_t *tvb _U_, packet_info *pinfo _U_, proto_tree *tree _U_, void *data _U_); static int dissect_AircraftPDUs_PDU( tvbuff_t *tvb _U_, packet_info *pinfo _U_, proto_tree *tree _U_, void *data _U_); static int dissect_ProtectedGroundPDUs_PDU( tvbuff_t *tvb _U_, packet_info *pinfo _U_, proto_tree *tree _U_, void *data _U_); static int dissect_ProtectedAircraftPDUs_PDU( tvbuff_t *tvb _U_, packet_info *pinfo _U_, proto_tree *tree _U_, void *data _U_); #include "packet-atn-cpdlc-hf.c" #include "packet-atn-cpdlc-ett.c" static gint ett_atn_cpdlc = -1; #include "packet-atn-cpdlc-fn.c" /* Wireshark ID of CPDLC protocol */ static int proto_atn_cpdlc = -1; static int dissect_atn_cpdlc( tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_) { /* note: */ /* there are two co-existing applications of CPDLC: */ /* "plain old" (ae-qualifier 2) and */ /* "protected mode" (ae-qualifier 22) CPDLC. */ /* "protected mode" was introduced to cope with a */ /* safety issue in which a message would sent to the wrong aircraft. */ /* note:*/ /* The protection is an additional checksum and covers the message content, */ /* the 24-bit address of the aircraft, the current flight id and */ /* the current ground facility so that an aircraft would be able to reject */ /* messages which are unexpected (i.e. messages to another flight or */ /* messages from the wrong center). */ /*note:*/ /* although "plain old" CPDLC is more or less deprecated */ /* many aircraft cannot perform */ /* "protected mode" for this largely depends on */ /* upgraded avionics packages */ /*note:*/ /* The use of CPDLC is *optional* as the pilot */ /* may always use a voice radio channel to talk to the controller.*/ proto_tree *atn_cpdlc_tree = NULL; atn_conversation_t *atn_cv = NULL; /* note: */ /* we need the ae qualifier stored within the conversation */ /* to decode "plain old cpdlc" or */ /* "protected mode cpdlc correctly " */ /* DT: dstref present, srcref is always zero */ if((pinfo->clnp_dstref) && (!pinfo->clnp_srcref)){ atn_cv = find_atn_conversation( &pinfo->dst, pinfo->clnp_dstref, &pinfo->src ); } /* CR: srcref present, dstref is always zero */ if((!pinfo->clnp_dstref) && (pinfo->clnp_srcref)){ atn_cv = find_atn_conversation( &pinfo->src, pinfo->clnp_srcref, &pinfo->dst ); } /* CC: srcref and dstref present, always use src/srcref & dst */ if((pinfo->clnp_dstref) && (pinfo->clnp_srcref)){ atn_cv = find_atn_conversation( &pinfo->src, pinfo->clnp_srcref, &pinfo->dst ); } if(!atn_cv){ /* atn conversation not found */ return 0; } atn_cpdlc_tree = proto_tree_add_subtree( tree, tvb, 0, -1, ett_atn_cpdlc, NULL, ATN_CPDLC_PROTO ); switch(atn_cv->ae_qualifier){ case pmcpdlc: if( check_heur_msg_type(pinfo) == um ) { /* uplink PDU's = Ground PDU's */ dissect_ProtectedGroundPDUs_PDU( tvb, pinfo, atn_cpdlc_tree, NULL); }else { /* downlink PDU's = Aircraft PDU's */ dissect_ProtectedAircraftPDUs_PDU( tvb, pinfo, atn_cpdlc_tree, NULL); } break; case cpdlc: if( check_heur_msg_type(pinfo) == um ) { /* uplink PDU's = Ground PDU's */ dissect_GroundPDUs_PDU( tvb, pinfo, atn_cpdlc_tree, NULL); }else { /* downlink PDU's = Aircraft PDU's */ dissect_AircraftPDUs_PDU( tvb, pinfo, atn_cpdlc_tree, NULL); } break; default: break; } return tvb_reported_length_remaining(tvb, 0); } static gboolean dissect_atn_cpdlc_heur( tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_) { atn_conversation_t *atn_cv = NULL; volatile gboolean is_atn_cpdlc = FALSE; volatile gboolean is_pm = FALSE; int type; type = check_heur_msg_type(pinfo); switch(type){ case um: TRY { dissect_ProtectedGroundPDUs_PDU(tvb, pinfo, NULL, NULL); is_atn_cpdlc = TRUE; is_pm = TRUE; break;} CATCH_ALL{ is_atn_cpdlc = FALSE; is_pm = FALSE;} ENDTRY; TRY { dissect_GroundPDUs_PDU(tvb, pinfo, NULL, NULL); is_pm = FALSE; is_atn_cpdlc = TRUE; break;} CATCH_ALL{ is_atn_cpdlc = FALSE; is_pm = FALSE;} ENDTRY; break; case dm: TRY { dissect_ProtectedAircraftPDUs_PDU(tvb, pinfo, NULL, NULL); is_atn_cpdlc = TRUE; is_pm = TRUE; break;} CATCH_ALL { is_atn_cpdlc = FALSE; is_pm = FALSE; } ENDTRY; TRY{ dissect_AircraftPDUs_PDU(tvb, pinfo, NULL, NULL); is_atn_cpdlc = TRUE; is_pm = FALSE; break;} CATCH_ALL{ is_atn_cpdlc = FALSE; is_pm = FALSE;} ENDTRY; break; default: break; } if(is_atn_cpdlc){ /* note: */ /* all subsequent PDU's belonging to this conversation */ /* are considered CPDLC */ /* if the first CPDLC PDU has been decoded succesfully */ /* (This is done in "atn-ulcs" by using "call_dissector_with_data()") */ /* DT: dstref present, srcref is always zero */ if((pinfo->clnp_dstref) && (!pinfo->clnp_srcref)){ atn_cv = find_atn_conversation(&pinfo->dst, pinfo->clnp_dstref, &pinfo->src ); } /* CR: srcref present, dstref is always zero */ if((!pinfo->clnp_dstref) && (pinfo->clnp_srcref)){ atn_cv = find_atn_conversation(&pinfo->src, pinfo->clnp_srcref, &pinfo->dst ); } /* CC: srcref and dstref present, always use src/srcref & dst */ if((pinfo->clnp_dstref) && (pinfo->clnp_srcref)){ atn_cv = find_atn_conversation(&pinfo->src, pinfo->clnp_srcref, &pinfo->dst ); } if(atn_cv){ /* atn conversation found */ if(is_pm == TRUE) { atn_cv->ae_qualifier = pmcpdlc; } else { atn_cv->ae_qualifier = cpdlc; } dissect_atn_cpdlc(tvb, pinfo, tree, NULL); } }else { /* there should *always* be an atn conversation */ is_atn_cpdlc = FALSE; } return is_atn_cpdlc; } void proto_register_atn_cpdlc (void) { static hf_register_info hf_atn_cpdlc[] = { #include "packet-atn-cpdlc-hfarr.c" }; static gint *ett[] = { #include "packet-atn-cpdlc-ettarr.c" &ett_atn_cpdlc }; /* register CPDLC */ proto_atn_cpdlc = proto_register_protocol( ATN_CPDLC_PROTO , "ATN-CPDLC", "atn-cpdlc"); proto_register_field_array( proto_atn_cpdlc, hf_atn_cpdlc, array_length(hf_atn_cpdlc)); proto_register_subtree_array( ett, array_length(ett)); new_register_dissector( "atn-cpdlc", dissect_atn_cpdlc, proto_atn_cpdlc); } void proto_reg_handoff_atn_cpdlc(void) { /* add session dissector to atn dissector list dissector list*/ heur_dissector_add( "atn-ulcs", dissect_atn_cpdlc_heur, proto_atn_cpdlc); } /* * Editor modelines - http://www.wireshark.org/tools/modelines.html * * Local variables: * c-basic-offset: 2 * tab-width: 2 * indent-tabs-mode: t * End: * * vi: set shiftwidth=2 tabstop=2 noexpandtab: * :indentSize=2:tabSize=2:noTabs=false: */