| % M2PA in accordance with RFC4165 (http://tools.ietf.org/html/rfc4665) |
| |
| % (C) 2011-2012 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(sctp_m2pa). |
| -author('Harald Welte <laforge@gnumonks.org>'). |
| -behaviour(sctp_core). |
| |
| -include_lib("kernel/include/inet_sctp.hrl"). |
| -include("osmo_util.hrl"). |
| -include("m2pa.hrl"). |
| |
| -export([init/1, terminate/3, code_change/4, handle_event/3, handle_info/3]). |
| |
| -export([rx_sctp/4, mtp_xfer/2, state_change/3, prim_up/3]). |
| |
| -record(m2pa_state, { |
| last_bsn_received, |
| last_fsn_sent, |
| lsc_pid, |
| iac_pid, |
| msu_fisu_accepted |
| }). |
| |
| %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
| % gen_fsm callbacks |
| %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
| |
| init(_InitOpts) -> |
| % start MTP2 IAC FSM pointing LSC, AERM and TXC to us |
| {ok, Lsc} = gen_fsm:start_link(mtp2_lsc, [self(), self(), self(), self(),self()], [{debug, [trace]}]), |
| {ok, Iac} = gen_fsm:sync_send_event(Lsc, get_iac_pid), |
| gen_fsm:send_event(Lsc, power_on), |
| {ok, #m2pa_state{last_bsn_received=16#ffffff, last_fsn_sent=16#ffffff, |
| lsc_pid=Lsc, iac_pid=Iac, |
| msu_fisu_accepted = 0}}. |
| |
| terminate(Reason, _State, _LoopDat) -> |
| io:format("Terminating ~p (Reason ~p)~n", [?MODULE, Reason]), |
| ok. |
| |
| code_change(_OldVsn, _State, LoopDat, _Extra) -> |
| {ok, LoopDat}. |
| |
| handle_event(_Event, State, LoopDat) -> |
| {next_state, State, LoopDat}. |
| |
| handle_info({lsc_txc, What}, State, LoopDat) when |
| What == start; What == retrieval_request_and_fsnc -> |
| {next_state, State, LoopDat}; |
| handle_info({lsc_rc, accept_msu_fisu}, State, LoopDat) -> |
| {next_state, State, LoopDat#m2pa_state{msu_fisu_accepted = 1}}; |
| handle_info({lsc_rc, reject_msu_fisu}, State, LoopDat) -> |
| {next_state, State, LoopDat#m2pa_state{msu_fisu_accepted = 0}}; |
| handle_info({Who, What}, established, LoopDat) when Who == iac_txc; Who == lsc_txc -> |
| Ls = iac_to_ls(What), |
| send_linkstate(Ls, LoopDat), |
| {next_state, established, LoopDat}; |
| handle_info(_Info, State, LoopDat) -> |
| {next_state, State, LoopDat}. |
| |
| %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
| % sctp_core callbacks |
| %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
| |
| prim_up(Prim, State, LoopDat) -> |
| % default: forward all primitives to the user |
| {ok, Prim, LoopDat}. |
| |
| |
| % sctp_core indicates that we have received some data... |
| rx_sctp(#sctp_sndrcvinfo{ppid = ?M2PA_PPID}, Data, State, LoopDat) -> |
| {ok, M2pa} = m2pa_codec:parse_msg(Data), |
| FsnRecv = M2pa#m2pa_msg.fwd_seq_nr, |
| % FIXME: check sequenc number linearity |
| case M2pa of |
| #m2pa_msg{msg_class = ?M2PA_CLASS_M2PA, |
| msg_type = ?M2PA_TYPE_USER} -> |
| Mtp3 = M2pa#m2pa_msg.mtp3, |
| case LoopDat#m2pa_state.msu_fisu_accepted of |
| 1 -> |
| LoopDat2 = LoopDat#m2pa_state{last_bsn_received = FsnRecv}, |
| case Mtp3 of |
| undefined -> |
| ok; |
| _ -> |
| send_userdata_ack(LoopDat2) |
| end, |
| gen_fsm:send_event(LoopDat#m2pa_state.lsc_pid, fisu_msu_received), |
| Prim = osmo_util:make_prim('MTP','TRANSFER',indication, Mtp3), |
| {ok, Prim, LoopDat2}; |
| _ -> |
| {ignore, LoopDat} |
| end; |
| #m2pa_msg{msg_type = ?M2PA_TYPE_LINK} -> |
| handle_linkstate(M2pa, LoopDat), |
| {ignore, LoopDat}; |
| _ -> |
| % do something with link related msgs |
| io:format("M2PA Unknown message ~p in state ~p~n", [M2pa, State]), |
| {ignore, State, LoopDat} |
| end. |
| |
| % MTP-TRANSFER.req has arrived at sctp_core, encapsulate+tx it |
| mtp_xfer(Mtp3, LoopDat) -> |
| Fsn = inc_seq_nr(LoopDat#m2pa_state.last_fsn_sent), |
| M2pa = #m2pa_msg{msg_class = ?M2PA_CLASS_M2PA, |
| msg_type = ?M2PA_TYPE_USER, |
| fwd_seq_nr = Fsn, |
| back_seq_nr = LoopDat#m2pa_state.last_bsn_received, |
| mtp3 = Mtp3}, |
| M2paBin = m2pa_codec:encode_msg(M2pa), |
| LoopDat2 = LoopDat#m2pa_state{last_fsn_sent = Fsn}, |
| tx_sctp(?M2PA_STREAM_USER, M2paBin), |
| LoopDat2. |
| |
| state_change(_, established, LoopDat) -> |
| % emulate a 'start' from LSC |
| gen_fsm:send_event(LoopDat#m2pa_state.lsc_pid, start), |
| LoopDat; |
| state_change(established, _, LoopDat) -> |
| gen_fsm:send_event(LoopDat#m2pa_state.lsc_pid, link_failure), |
| LoopDat; |
| state_change(_, _, LoopDat) -> |
| LoopDat. |
| |
| |
| %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
| % helper functions |
| %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
| |
| inc_seq_nr(SeqNr) when is_integer(SeqNr) -> |
| SeqNr + 1 rem 16#FFFFFF. |
| |
| handle_linkstate(M2pa, LoopDat) when is_record(M2pa, m2pa_msg) -> |
| Linkstate = proplists:get_value(link_state, M2pa#m2pa_msg.parameters), |
| LsMtp2 = ls_to_iac(Linkstate), |
| if LsMtp2 == fisu -> |
| case LoopDat#m2pa_state.msu_fisu_accepted of |
| 1 -> |
| gen_fsm:send_event(LoopDat#m2pa_state.lsc_pid, |
| fisu_msu_received); |
| 0 -> ok |
| end; |
| LsMtp2 == si_po -> |
| gen_fsm:send_event(LoopDat#m2pa_state.lsc_pid, LsMtp2); |
| LsMtp2 == si_n; LsMtp2 == si_e; LsMtp2 == si_o; LsMtp2 == si_os -> |
| gen_fsm:send_event(LoopDat#m2pa_state.lsc_pid, LsMtp2) |
| % IAC will receive the event as pass-through from LSC |
| %gen_fsm:send_event(LoopDat#m2pa_state.iac_pid, LsMtp2) |
| end. |
| |
| % convert M2PA link state to MTP2 |
| ls_to_iac(?M2PA_LS_OOS) -> |
| si_os; |
| ls_to_iac(?M2PA_LS_ALIGNMENT) -> |
| si_o; |
| ls_to_iac(?M2PA_LS_PROVING_NORMAL) -> |
| si_n; |
| ls_to_iac(?M2PA_LS_PROVING_EMERG) -> |
| si_e; |
| ls_to_iac(?M2PA_LS_READY) -> |
| fisu; |
| ls_to_iac(?M2PA_LS_PROC_OUTAGE) -> |
| si_po; |
| ls_to_iac(?M2PA_LS_PROC_RECOVERED) -> |
| fisu; |
| ls_to_iac(?M2PA_LS_BUSY) -> |
| si_b. |
| % FIXME: what about BUSY_ENDED? |
| |
| |
| % convert MTP2 link state to M2PA |
| iac_to_ls(si_os) -> |
| ?M2PA_LS_OOS; |
| iac_to_ls(si_o) -> |
| ?M2PA_LS_ALIGNMENT; |
| iac_to_ls(si_n) -> |
| ?M2PA_LS_PROVING_NORMAL; |
| iac_to_ls(si_e) -> |
| ?M2PA_LS_PROVING_EMERG; |
| iac_to_ls(fisu) -> |
| ?M2PA_LS_READY; |
| iac_to_ls(msu) -> |
| ?M2PA_LS_READY; |
| iac_to_ls(si_po) -> |
| ?M2PA_LS_PROC_OUTAGE; |
| iac_to_ls(si_b) -> |
| ?M2PA_LS_BUSY. |
| |
| % Chapter 4.1.2 of RFC4165 |
| ls_stream(?M2PA_LS_PROC_OUTAGE) -> |
| 1; |
| ls_stream(?M2PA_LS_PROC_RECOVERED) -> |
| 1; |
| ls_stream(Foo) when is_integer(Foo) -> |
| 0. |
| |
| send_linkstate(Ls, LoopDat) when is_integer(Ls) -> |
| Stream = ls_stream(Ls), |
| M2pa = #m2pa_msg{msg_class = ?M2PA_CLASS_M2PA, |
| msg_type = ?M2PA_TYPE_LINK, |
| fwd_seq_nr = LoopDat#m2pa_state.last_fsn_sent, |
| back_seq_nr = LoopDat#m2pa_state.last_bsn_received, |
| parameters = [{link_state, Ls}]}, |
| M2paBin = m2pa_codec:encode_msg(M2pa), |
| tx_sctp(Stream, M2paBin), |
| LoopDat. |
| |
| send_userdata_ack(LoopDat) -> |
| M2pa = #m2pa_msg{msg_class = ?M2PA_CLASS_M2PA, |
| msg_type = ?M2PA_TYPE_USER, |
| fwd_seq_nr = LoopDat#m2pa_state.last_fsn_sent, |
| back_seq_nr = LoopDat#m2pa_state.last_bsn_received}, |
| M2paBin = m2pa_codec:encode_msg(M2pa), |
| tx_sctp(0, M2paBin). |
| |
| tx_sctp(Stream, Payload) when is_integer(Stream), is_binary(Payload) -> |
| Param = {Stream, ?M2PA_PPID, Payload}, |
| % sent to 'ourselves' (behaviour master module) |
| gen_fsm:send_event(self(), osmo_util:make_prim('SCTP','TRANSFER',request,Param)). |