/* packet-atn-cpdlc-template.c * By Mathias Guettler * Copyright 2013 * * Routines for ATN Cpdlcc protocol packet disassembly * * details see: * https://en.wikipedia.org/wiki/CPDLC * https://members.optusnet.com.au/~cjr/introduction.htm * * standards: * We are dealing with ATN/CPDLC aka ICAO Doc 9705 Second Edition here * (CPDLC may also be transmitted via ACARS/AOA aka "FANS-1/A "). * https://www.icao.int/safety/acp/repository/_%20Doc9705_ed2_1999.pdf * * Wireshark - Network traffic analyzer * By Gerald Combs * Copyright 1998 Gerald Combs * * SPDX-License-Identifier: GPL-2.0-or-later */ /* 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 "packet-ber.h" #include "packet-per.h" #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; /* IA5 charset (7-bit) for PER IA5 decoding */ static const char ia5alpha[] = { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, \ 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, \ 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, \ 0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f, \ 0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f, \ 0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f, \ 0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59, 0x5a, 0x5b, 0x5c, 0x5d, 0x5e, 0x5f, \ 0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f, \ 0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7a, 0x7b, 0x7c, 0x7d, 0x7e, 0x7f, '\0' }; /* 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 int ett_atn_cpdlc; #include "packet-atn-cpdlc-fn.c" /* Wireshark ID of CPDLC protocol */ static int proto_atn_cpdlc; 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 bool dissect_atn_cpdlc_heur( tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_) { atn_conversation_t *volatile atn_cv = NULL; volatile bool is_atn_cpdlc = false; volatile bool 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;} CATCH_ALL{ is_atn_cpdlc = false; is_pm = false;} ENDTRY; if (is_atn_cpdlc) { break; } TRY { dissect_GroundPDUs_PDU(tvb, pinfo, NULL, NULL); is_pm = false; is_atn_cpdlc = true;} 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;} CATCH_ALL { is_atn_cpdlc = false; is_pm = false; } ENDTRY; if (is_atn_cpdlc) { break; } TRY{ dissect_AircraftPDUs_PDU(tvb, pinfo, NULL, NULL); is_atn_cpdlc = true; is_pm = false;} 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 successfully */ /* (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 int *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)); 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, "ATN-CPDLC over ATN-ULCS", "atn-cpdlc-ulcs", proto_atn_cpdlc, HEURISTIC_ENABLE); } /* * Editor modelines - https://www.wireshark.org/tools/modelines.html * * Local variables: * c-basic-offset: 4 * tab-width: 8 * indent-tabs-mode: nil * End: * * vi: set shiftwidth=4 tabstop=8 expandtab: * :indentSize=4:tabSize=8:noTabs=true: */