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% M3UA in accordance with RFC4666 (http://tools.ietf.org/html/rfc4666)
% (C) 2011 by Harald Welte <laforge@gnumonks.org>
%
% All Rights Reserved
%
% This program is free software; you can redistribute it and/or modify
% it under the terms of the GNU Affero General Public License as
% published by the Free Software Foundation; either version 3 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 Affero General Public License
% along with this program. If not, see <http://www.gnu.org/licenses/>.
%
% Additional Permission under GNU AGPL version 3 section 7:
%
% If you modify this Program, or any covered work, by linking or
% combining it with runtime libraries of Erlang/OTP as released by
% Ericsson on http://www.erlang.org (or a modified version of these
% libraries), containing parts covered by the terms of the Erlang Public
% License (http://www.erlang.org/EPLICENSE), the licensors of this
% Program grant you additional permission to convey the resulting work
% without the need to license the runtime libraries of Erlang/OTP under
% the GNU Affero General Public License. Corresponding Source for a
% non-source form of such a combination shall include the source code
% for the parts of the runtime libraries of Erlang/OTP used as well as
% that of the covered work.
-module(m3ua_codec).
-author('Harald Welte <laforge@gnumonks.org>').
-include("m3ua.hrl").
-include("mtp3.hrl").
-export([parse_m3ua_msg/1, encode_m3ua_msg/1]).
%-compile(export_all).
-compile({parse_transform, exprecs}).
-export_records([m3ua_msg]).
% compute the number of pad bits required after a binary parameter
get_num_pad_bytes(BinLenBytes) ->
case BinLenBytes rem 4 of
0 -> 0;
Val -> 4 - Val
end.
parse_m3ua_msg(DataBin) when is_binary(DataBin) ->
<<Version:8, _Reserved:8, MsgClass:8, MsgType:8, MsgLen:32/big, Remain/binary>> = DataBin,
OptList = parse_m3ua_opts(Remain),
#m3ua_msg{version = Version, msg_class = MsgClass, msg_type = MsgType,
msg_length = MsgLen-4, payload = OptList};
parse_m3ua_msg(Data) when is_list(Data) ->
parse_m3ua_msg(list_to_binary(Data)).
parse_m3ua_opts(OptBin) when is_binary(OptBin) ->
parse_m3ua_opts(OptBin, []).
parse_m3ua_opts(<<>>, OptList) when is_list(OptList) ->
OptList;
parse_m3ua_opts(OptBin, OptList) when is_binary(OptBin), is_list(OptList) ->
<<Tag:16/big, Length:16/big, Remain/binary>> = OptBin,
PadLen = get_num_pad_bytes(Length),
LengthNet = Length - 4,
<<CurOpt:LengthNet/binary, 0:PadLen/integer-unit:8, Remain2/binary>> = Remain,
NewOpt = parse_m3ua_opt(Tag, CurOpt),
parse_m3ua_opts(Remain2, OptList ++ [NewOpt]).
parse_m3ua_opt(Opt = ?M3UA_IEI_PROTOCOL_DATA, MsgBin) when is_binary(MsgBin) ->
<<Opc:32/big, Dpc:32/big, Si:8, Ni:8, Mp:8, Sls:8, Payload/binary>> = MsgBin,
% The idea is to hand back a #mtp3_msg{} to make upper layers beyond
% MTP-TRANSFR.{ind,req} unaware of a MTP3 or M3UA lower layer
{Opt, #mtp3_msg{network_ind = Ni, service_ind = Si,
routing_label = #mtp3_routing_label{sig_link_sel = Sls,
origin_pc = Opc,
dest_pc = Dpc},
payload = Payload, m3ua_mp = Mp}};
parse_m3ua_opt(Opt, Msg) ->
{Opt, Msg}.
encode_m3ua_msg(#m3ua_msg{version = Version, msg_class = MsgClass,
msg_type = MsgType, payload = OptList}) ->
OptBin = encode_m3ua_opts(OptList),
MsgLen = byte_size(OptBin) + 8,
<<Version:8, 0:8, MsgClass:8, MsgType:8, MsgLen:32/big, OptBin/binary>>.
encode_m3ua_opts(OptList) when is_list(OptList) ->
encode_m3ua_opts(OptList, <<>>).
encode_m3ua_opts([], Bin) ->
Bin;
encode_m3ua_opts([{Iei, Attr}|Tail], Bin) ->
OptBin = encode_m3ua_opt(Iei, Attr),
encode_m3ua_opts(Tail, <<Bin/binary, OptBin/binary>>).
encode_m3ua_opt(?M3UA_IEI_PROTOCOL_DATA, Mtp3) when is_record(Mtp3, mtp3_msg) ->
#mtp3_msg{network_ind = Ni, service_ind = Si,
routing_label = #mtp3_routing_label{sig_link_sel = Sls,
origin_pc = OpcIn,
dest_pc = DpcIn},
payload = Payload, m3ua_mp = Mp} = Mtp3,
Opc = osmo_util:pointcode2int(OpcIn),
Dpc = osmo_util:pointcode2int(DpcIn),
case Mp of
undefined -> MpD = 0;
_ -> MpD = Mp
end,
PayBin = <<Opc:32/big, Dpc:32/big, Si:8, Ni:8, MpD:8, Sls:8, Payload/binary>>,
encode_m3ua_opt(?M3UA_IEI_PROTOCOL_DATA, PayBin);
encode_m3ua_opt(Iei, Data) when is_integer(Iei), is_binary(Data) ->
Length = byte_size(Data) + 4,
PadLen = get_num_pad_bytes(Length),
<<Iei:16/big, Length:16/big, Data/binary, 0:PadLen/integer-unit:8>>.
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