Move actual packet manipulation code to mgw_nat.erl
diff --git a/src/mgw_nat.erl b/src/mgw_nat.erl
new file mode 100644
index 0000000..6cdaa8c
--- /dev/null
+++ b/src/mgw_nat.erl
@@ -0,0 +1,121 @@
+%
+
+% (C) 2011 by Harald Welte <laforge@gnumonks.org>
+% (C) 2011 OnWaves
+%
+% 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/>.
+
+-module(mgw_nat).
+-author("Harald Welte <laforge@gnumonks.org>").
+-export([mangle_rx_data/3]).
+
+%-include_lib("kernel/include/inet.hrl").
+%-include_lib("kernel/include/inet_sctp.hrl").
+
+-include("m2ua.hrl").
+-include("mtp3.hrl").
+-include("isup.hrl").
+-include("sccp.hrl").
+
+% mangle the received data
+mangle_rx_data(L, From, Data) when is_binary(Data) ->
+ {ok, M2ua} = m2ua_codec:parse_m2ua_msg(Data),
+ %io:format("M2UA Decode: ~p~n", [M2ua]),
+ case M2ua of
+ #m2ua_msg{msg_class = ?M2UA_MSGC_MAUP,
+ msg_type = ?M2UA_MAUP_MSGT_DATA} ->
+ M2ua_out = mangle_rx_m2ua_maup(L, From, M2ua);
+ #m2ua_msg{} ->
+ % simply pass it along unmodified
+ M2ua_out = M2ua
+ end,
+ % re-encode the data
+ %io:format("M2UA Encode: ~p~n", [M2ua_out]),
+ m2ua_codec:encode_m2ua_msg(M2ua_out).
+
+% mangle the received M2UA
+mangle_rx_m2ua_maup(L, From, M2ua = #m2ua_msg{parameters = Params}) ->
+ {_Len, M2uaPayload} = proplists:get_value(16#300, Params),
+ Mtp3 = mtp3_codec:parse_mtp3_msg(M2uaPayload),
+ %io:format("MTP3 Decode: ~p~n", [Mtp3]),
+ Mtp3_out = mangle_rx_mtp3(L, From, Mtp3),
+ %io:format("MTP3 Encode: ~p~n", [Mtp3_out]),
+ Mtp3OutBin = mtp3_codec:encode_mtp3_msg(Mtp3_out),
+ Params2 = proplists:delete(16#300, Params),
+ ParamsNew = Params2 ++ [{16#300, {byte_size(Mtp3OutBin), Mtp3OutBin}}],
+ % return mangled parsed m2ua msg
+ M2ua#m2ua_msg{parameters = ParamsNew}.
+
+% mangle the MTP3 payload
+mangle_rx_mtp3(L, From, Mtp3 = #mtp3_msg{service_ind = Service}) ->
+ mangle_rx_mtp3_serv(L, From, Service, Mtp3).
+
+% mangle the ISUP content
+mangle_rx_mtp3_serv(L, From, ?MTP3_SERV_ISUP, Mtp3 = #mtp3_msg{payload = Payload}) ->
+ io:format("ISUP In: ~p~n", [Payload]),
+ Isup = isup_codec:parse_isup_msg(Payload),
+ io:format("ISUP Decode: ~p~n", [Isup]),
+ % FIXME
+ %mangle_rx_isup(From, Isup#isup_msg.msg_type, Isup),
+ case Isup#isup_msg.msg_type of
+ ?ISUP_MSGT_IAM ->
+ io:format("ISUP Encode In: ~p~n", [Isup]),
+ Isup_out = isup_codec:encode_isup_msg(Isup),
+ io:format("ISUP Encode Out: ~p~n", [Isup_out]),
+ % FIXME
+ if Isup_out == Payload -> ok;
+ true -> io:format("ISUP DATA NOT EQUAL!~n")
+ end,
+ % return modified MTP3 payload
+ Mtp3#mtp3_msg{payload = Isup_out};
+ _ ->
+ % return UNmodified MTP3 payload
+ Mtp3
+ end;
+% mangle the SCCP content
+mangle_rx_mtp3_serv(L, From, ?MTP3_SERV_SCCP, Mtp3 = #mtp3_msg{payload = Payload}) ->
+ Sccp = sccp_codec:parse_sccp_msg(Payload),
+ io:format("SCCP Decode: ~p~n", [Sccp]),
+ % FIXME
+ Mtp3;
+% default: do nothing
+mangle_rx_mtp3_serv(_L, _From, _, Mtp3) ->
+ Mtp3.
+
+-define(MSRN_PFX_MSC, [8,9,0,9,9]).
+-define(MSRN_PFX_STP, [9,2,9,9,4,2,0,0]).
+
+mangle_rx_isup(From, MsgType, Msg = #isup_msg{parameters = Params}) when
+ MsgType == ?ISUP_MSGT_IAM ->
+ CalledNum = proplists:get_value(?ISUP_PAR_CALLED_P_NUM, Params),
+ DigitsIn = CalledNum#party_number.phone_number,
+ Last2DigF = lists:sublist(DigitsIn, length(DigitsIn)-2, 3),
+ case From of
+ from_stp ->
+ DigitsOut = ?MSRN_PFX_MSC ++ Last2DigF,
+ io:format("IAM MSRN rewrite (MSC->STP): ~p -> ~p~n",
+ [DigitsIn, DigitsOut]);
+ from_msc ->
+ DigitsOut = DigitsIn,
+ io:format("No support for MSC->STP MSRN rewrite~n")
+ end,
+ CalledNumOut = CalledNum#party_number{phone_number=DigitsOut},
+ ParamsDel = proplists:delete(?ISUP_PAR_CALLED_P_NUM, Params),
+ ParamsOut = [{?ISUP_PAR_CALLED_P_NUM, CalledNumOut}|ParamsDel],
+ #isup_msg{parameters = ParamsOut};
+% default case: no mangling
+mangle_rx_isup(_From, _Type, Msg) when is_record(Msg, isup_msg) ->
+ Msg.