Harald Welte | d17e75a | 2011-01-18 18:25:20 +0100 | [diff] [blame] | 1 | % SCTP Handler for gateway between MSC and STP, transparently |
| 2 | % rewriting addresses on the fly |
| 3 | |
| 4 | % (C) 2011 by Harald Welte <laforge@gnumonks.org> |
| 5 | % (C) 2011 OnWaves |
| 6 | % |
| 7 | % All Rights Reserved |
| 8 | % |
| 9 | % This program is free software; you can redistribute it and/or modify |
| 10 | % it under the terms of the GNU Affero General Public License as |
| 11 | % published by the Free Software Foundation; either version 3 of the |
| 12 | % License, or (at your option) any later version. |
| 13 | % |
| 14 | % This program is distributed in the hope that it will be useful, |
| 15 | % but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 16 | % MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 17 | % GNU General Public License for more details. |
| 18 | % |
| 19 | % You should have received a copy of the GNU Affero General Public License |
| 20 | % along with this program. If not, see <http://www.gnu.org/licenses/>. |
| 21 | |
| 22 | |
| 23 | -module(sctp_handler). |
| 24 | -author("Harald Welte <laforge@gnumonks.org>"). |
Harald Welte | aca4edc | 2011-01-21 16:21:12 +0000 | [diff] [blame] | 25 | -export([init/5]). |
Harald Welte | d17e75a | 2011-01-18 18:25:20 +0100 | [diff] [blame] | 26 | |
| 27 | -include_lib("kernel/include/inet.hrl"). |
| 28 | -include_lib("kernel/include/inet_sctp.hrl"). |
| 29 | |
Harald Welte | aca4edc | 2011-01-21 16:21:12 +0000 | [diff] [blame] | 30 | %-include("m2ua.hrl"). |
| 31 | %-include("mtp3.hrl"). |
| 32 | %-include("isup.hrl"). |
| 33 | %-include("sccp.hrl"). |
Harald Welte | d17e75a | 2011-01-18 18:25:20 +0100 | [diff] [blame] | 34 | |
| 35 | -record(loop_data, |
| 36 | {msc_sock, msc_local_ip, msc_remote_ip, msc_remote_port, |
| 37 | msc_local_port, msc_assoc_id, |
| 38 | stp_sock, stp_remote_ip, stp_remote_port, stp_assoc_id |
| 39 | }). |
| 40 | |
| 41 | -define(COMMON_SOCKOPTS, [{active, once}, {reuseaddr, true}]). |
| 42 | |
| 43 | % initialize the sockets towards MSC (listening) and STP (connect) |
| 44 | init(MscLocalIP, MscLocalPort, MscRemoteIP, StpRemoteIP, StpRemotePort) -> |
| 45 | {ok, MscSock} = gen_sctp:open([{ip, MscLocalIP},{port,MscLocalPort}] |
| 46 | ++ ?COMMON_SOCKOPTS), |
| 47 | io:format("Listening for MSC on ~w:~w. ~w~n", |
| 48 | [MscLocalIP, MscLocalPort, MscSock]), |
| 49 | ok = gen_sctp:listen(MscSock, true), |
| 50 | {ok, StpSock} = gen_sctp:open(?COMMON_SOCKOPTS), |
| 51 | L = #loop_data{msc_sock = MscSock, msc_local_ip = MscLocalIP, |
| 52 | msc_remote_ip = MscRemoteIP, |
| 53 | stp_sock = StpSock, stp_remote_ip = StpRemoteIP, |
| 54 | stp_remote_port = StpRemotePort}, |
| 55 | loop(L). |
| 56 | |
| 57 | % initiate a connection to STP as a client |
| 58 | initiate_stp_connection(#loop_data{stp_sock = Sock, stp_remote_ip = IP, stp_remote_port = Port}, Opts) -> |
| 59 | io:format("Establishing SCTP conn to STP ~p Port ~p~n", [IP, Port]), |
| 60 | gen_sctp:connect(Sock, IP, Port, Opts ++ ?COMMON_SOCKOPTS). |
| 61 | |
| 62 | % main loop function |
| 63 | loop(L = #loop_data{msc_sock=MscSock, msc_remote_ip=MscRemoteIp, msc_remote_port=MscRemotePort, |
| 64 | stp_sock=StpSock, stp_remote_ip=StpRemoteIp, stp_remote_port=StpRemotePort}) -> |
| 65 | io:format("Entering receive loop ~p~n", [L]), |
| 66 | io:format("======================================================================~n"), |
| 67 | receive |
| 68 | % MSC connect or disconnect |
| 69 | {sctp, MscSock, MscRemoteIp, Port, {ANC, SAC}} |
| 70 | when is_record(SAC, sctp_assoc_change) -> |
| 71 | io:format("MSC sctp_assoc_change ~p ~p~n", [ANC, SAC]), |
| 72 | #sctp_assoc_change{state = SacState, outbound_streams = OutStreams, |
| 73 | inbound_streams = InStreams, assoc_id = MscAssocId} = SAC, |
| 74 | case SacState of |
| 75 | comm_up -> |
| 76 | InitMsg = #sctp_initmsg{num_ostreams=InStreams, |
| 77 | max_instreams=OutStreams}, |
| 78 | {ok, StpAssoc} = initiate_stp_connection(L, [{sctp_initmsg,InitMsg}]), |
| 79 | io:format("STP Assoc: ~p~n", [StpAssoc]), |
| 80 | NewL = L#loop_data{msc_remote_port = Port, |
| 81 | msc_assoc_id = MscAssocId, |
| 82 | stp_assoc_id = StpAssoc#sctp_assoc_change.assoc_id}; |
| 83 | comm_lost -> |
| 84 | NewL = L, |
| 85 | % maybe we should simply die? |
Harald Welte | bdc7a5c | 2011-01-21 14:50:15 +0000 | [diff] [blame] | 86 | io:format("MSC SCTP comm_lost~n"), |
Harald Welte | d17e75a | 2011-01-18 18:25:20 +0100 | [diff] [blame] | 87 | foo:bar(); |
| 88 | addr_unreachable -> |
| 89 | NewL = L, |
Harald Welte | bdc7a5c | 2011-01-21 14:50:15 +0000 | [diff] [blame] | 90 | io:format("MSC SCTP addr_unreachable~n"), |
Harald Welte | d17e75a | 2011-01-18 18:25:20 +0100 | [diff] [blame] | 91 | % maybe we should simply die? |
| 92 | foo:bar() |
| 93 | end, |
| 94 | inet:setopts(MscSock, [{active, once}]); |
| 95 | % STP connect or disconnect |
| 96 | {sctp, StpSock, StpRemoteIp, StpRemotePort, {_Anc, SAC}} |
| 97 | when is_record(SAC, sctp_assoc_change) -> |
| 98 | io:format("STP sctp_assoc_change ~p~n", [SAC]), |
| 99 | inet:setopts(StpSock, [{active, once}]), |
| 100 | NewL = L; |
| 101 | % MSC data |
| 102 | {sctp, MscSock, MscRemoteIp, MscRemotePort, {[Anc], Data}} -> |
| 103 | io:format("MSC rx data: ~p ~p~n", [Anc, Data]), |
| 104 | handle_rx_data(L, from_msc, Anc, Data), |
| 105 | inet:setopts(MscSock, [{active, once}]), |
| 106 | NewL = L; |
| 107 | % STP data |
| 108 | {sctp, StpSock, StpRemoteIp, StpRemotePort, {[Anc], Data}} -> |
| 109 | io:format("STP rx data: ~p ~p~n", [Anc, Data]), |
| 110 | handle_rx_data(L, from_stp, Anc, Data), |
| 111 | inet:setopts(StpSock, [{active, once}]), |
| 112 | NewL = L; |
Harald Welte | bdc7a5c | 2011-01-21 14:50:15 +0000 | [diff] [blame] | 113 | {sctp, _Sock, RemoteIp, _Remote_port, {_Anc, Data}} |
| 114 | when is_record(Data, sctp_shutdown_event) -> |
| 115 | % maybe we should simply die? |
| 116 | NewL = L, |
| 117 | io:format("SCTP remote ~p shutdown~n", [RemoteIp]), |
| 118 | foo:bar(); |
Harald Welte | d17e75a | 2011-01-18 18:25:20 +0100 | [diff] [blame] | 119 | Other -> |
| 120 | io:format("OTHER ~p~n", [Other]), |
| 121 | NewL = L |
| 122 | end, |
| 123 | loop(NewL). |
| 124 | |
Harald Welte | d17e75a | 2011-01-18 18:25:20 +0100 | [diff] [blame] | 125 | % handle incoming data on one of the SCTP sockets |
| 126 | handle_rx_data(L, From, SRInf = #sctp_sndrcvinfo{ppid = 2, |
| 127 | stream = Stream}, Data) when is_binary(Data) -> |
Harald Welte | aca4edc | 2011-01-21 16:21:12 +0000 | [diff] [blame] | 128 | DataOut = mgw_nat:mangle_rx_data(L, From, Data), |
Harald Welte | d17e75a | 2011-01-18 18:25:20 +0100 | [diff] [blame] | 129 | % send mangled data to other peer |
| 130 | case From of |
| 131 | from_msc -> |
| 132 | Sock = L#loop_data.stp_sock, |
| 133 | AssocId = L#loop_data.stp_assoc_id; |
| 134 | from_stp -> |
| 135 | Sock = L#loop_data.msc_sock, |
| 136 | AssocId = L#loop_data.msc_assoc_id |
| 137 | end, |
| 138 | SndRcvInfo = #sctp_sndrcvinfo{ppid = 2, stream = Stream, assoc_id = AssocId}, |
Harald Welte | bdc7a5c | 2011-01-21 14:50:15 +0000 | [diff] [blame] | 139 | %io:format("Sending ~p to ~p ~p~n", [DataOut, Sock, SndRcvInfo]), |
Harald Welte | d17e75a | 2011-01-18 18:25:20 +0100 | [diff] [blame] | 140 | % if they are not equal, we will abort here |
Harald Welte | 646074c | 2011-01-21 17:09:32 +0000 | [diff] [blame] | 141 | if DataOut == Data -> |
| 142 | ok; |
| 143 | true -> |
| 144 | io:format("Data is NOT equal~n") |
| 145 | end, |
Harald Welte | d17e75a | 2011-01-18 18:25:20 +0100 | [diff] [blame] | 146 | ok = gen_sctp:send(Sock, SndRcvInfo, DataOut). |
| 147 | |
Harald Welte | d17e75a | 2011-01-18 18:25:20 +0100 | [diff] [blame] | 148 | |