| % MTP2 Initial Alignment Control according to Q.703 Figure 4 / Figure 9 |
| |
| % (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/>. |
| |
| -module(mtp2_iac). |
| -author('Harald Welte <laforge@gnumonks.org>'). |
| -behaviour(gen_fsm). |
| |
| % gen_fsm exports |
| -export([init/1, terminate/3, code_change/4, handle_event/3, handle_info/3]). |
| |
| % states in this FSM |
| -export([idle/2, not_aligned/2, aligned/2, proving/2]). |
| |
| % Timeouts in milliseconds According to Q.703 / Section 12.3 |
| -define(M2PA_T1_DEF, 50000). |
| -define(M2PA_T2_DEF, 150000). |
| -define(M2PA_T3_DEF, 2000). |
| -define(M2PA_T4N_DEF, 8200). |
| -define(M2PA_T4E_DEF, 500). |
| |
| -record(iac_state, { |
| t2_timeout, |
| t3_timeout, |
| t4_timeout, |
| t4_timeout_pn, |
| t4_timeout_pe, |
| t2, t3, t4, |
| emergency, |
| cp, |
| further_prov, |
| lsc_pid, |
| aerm_pid, |
| txc_pid |
| }). |
| |
| %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
| % gen_fsm callbacks |
| %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
| |
| init([Lsc, Aerm, Txc]) -> |
| IacState = #iac_state{t2_timeout = ?M2PA_T2_DEF, |
| t3_timeout = ?M2PA_T3_DEF, |
| t4_timeout_pn = ?M2PA_T4N_DEF, |
| t4_timeout_pe = ?M2PA_T4E_DEF, |
| emergency = 0, |
| cp = 0, |
| further_prov = 1, |
| lsc_pid = Lsc, |
| aerm_pid = Aerm, |
| txc_pid = Txc}, |
| {ok, idle, IacState}. |
| |
| terminate(Reason, State, _LoopDat) -> |
| io:format("Terminating ~p in State ~p (Reason: ~p)~n", |
| [?MODULE, State, Reason]), |
| ok. |
| |
| code_change(_OldVsn, StateName, LoopDat, _Extra) -> |
| {ok, StateName, LoopDat}. |
| |
| handle_event(Event, State, LoopDat) -> |
| io:format("Unknown Event ~p in state ~p~n", [Event, State]), |
| {next_state, State, LoopDat}. |
| |
| |
| handle_info(Info, State, LoopDat) -> |
| io:format("Unknown Info ~p in state ~p~n", [Info, State]), |
| {next_state, State, LoopDat}. |
| |
| %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
| % STATE "idle" |
| %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
| |
| idle(start, LoopDat) -> |
| % send sio |
| send_to_txc(si_o, LoopDat), |
| % start timer |
| T2tout = LoopDat#iac_state.t2_timeout, |
| {ok, T2} = timer:apply_after(T2tout, gen_fsm, send_event, |
| [self(), {timer_expired, t2}]), |
| {next_state, not_aligned, LoopDat#iac_state{t2 = T2}}; |
| idle(emergency, LoopDat) -> |
| % mark emergency |
| {next_state, idle, LoopDat#iac_state{emergency = 1}}. |
| |
| |
| %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
| % STATE "not aligned" |
| %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
| |
| not_aligned(stop, LoopDat) -> |
| % stop T2 |
| timer:cancel(LoopDat#iac_state.t2), |
| % cancel emergency |
| {next_state, idle, LoopDat#iac_state{emergency=0}}; |
| not_aligned(si_e, LoopDat) -> |
| % stop T2 |
| timer:cancel(LoopDat#iac_state.t2), |
| T4tout = LoopDat#iac_state.t4_timeout_pe, |
| % send SIE or SIN |
| case LoopDat#iac_state.emergency of |
| 0 -> |
| Send = si_n; |
| _ -> |
| Send = si_e |
| end, |
| send_to_txc(Send, LoopDat), |
| % start T3 |
| T3tout = LoopDat#iac_state.t3_timeout, |
| {ok, T3} = timer:apply_after(T3tout, gen_fsm, send_event, |
| [self(), {timer_expired, t3}]), |
| {next_state, aligned, LoopDat#iac_state{t3 = T3, t2 = undefined, t4_timeout = T4tout}}; |
| not_aligned(What, LoopDat) when What == si_o; What == si_n -> |
| % stop T2 |
| timer:cancel(LoopDat#iac_state.t2), |
| % send SIE or SIN |
| case LoopDat#iac_state.emergency of |
| 0 -> |
| T4tout = LoopDat#iac_state.t4_timeout_pn, |
| Send = si_n; |
| _ -> |
| T4tout = LoopDat#iac_state.t4_timeout_pe, |
| Send = si_e |
| end, |
| send_to_txc(Send, LoopDat), |
| T3tout = LoopDat#iac_state.t3_timeout, |
| {ok, T3} = timer:apply_after(T3tout, gen_fsm, send_event, |
| [self(), {timer_expired, t3}]), |
| {next_state, aligned, LoopDat#iac_state{t3 = T3, t2 = undefined, t4_timeout = T4tout}}; |
| not_aligned(emergency, LoopDat) -> |
| % mark emergency |
| {next_state, not_aligned, LoopDat#iac_state{emergency=1}}; |
| not_aligned(si_os, LoopDat) -> |
| % ignore SIOS in this state, as some implementations (notably |
| % yate) seem to send it in violation of the spec |
| {next_state, not_aligned, LoopDat}; |
| not_aligned({timer_expired, t2}, LoopDat) -> |
| % send 'alignment not possible' to LSC |
| send_to_lsc(alignment_not_possible, LoopDat), |
| % stop emergency |
| {next_state, idle, LoopDat#iac_state{emergency=0}}. |
| |
| |
| %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
| % STATE "aligned" |
| %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
| aligned(What, LoopDat) when What == si_n; What == si_e -> |
| case What of |
| si_e -> |
| % set T4 to Pe |
| T4tout = LoopDat#iac_state.t4_timeout_pe; |
| _ -> |
| T4tout = LoopDat#iac_state.t4_timeout_pn |
| end, |
| % stop T3 |
| timer:cancel(LoopDat#iac_state.t3), |
| ToutPE = LoopDat#iac_state.t4_timeout_pe, |
| case T4tout of |
| ToutPE -> |
| % set i to ie IAC->AERM |
| send_to_aerm(set_i_to_ie, LoopDat); |
| _ -> |
| ok |
| end, |
| % send Start to AERM |
| send_to_aerm(start, LoopDat), |
| % start T4 |
| {ok, T4} = timer:apply_after(T4tout, gen_fsm, send_event, |
| [self(), {timer_expired, t4}]), |
| % Cp := 0 |
| % cancel further proving? |
| LoopDat2 = LoopDat#iac_state{t4 = T4, t4_timeout = T4tout, |
| cp = 0, further_prov = 0}, |
| {next_state, proving, LoopDat2}; |
| aligned(emergency, LoopDat) -> |
| % Send SIE |
| send_to_txc(si_e, LoopDat), |
| T4tout = LoopDat#iac_state.t4_timeout_pe, |
| {next_State, aligned, LoopDat#iac_state{t4_timeout = T4tout}}; |
| aligned(si_os, LoopDat) -> |
| % Send alignment not possible |
| send_to_lsc(alignment_not_possible, LoopDat), |
| % stop T3 |
| timer:cancel(LoopDat#iac_state.t3), |
| {next_state, idle, LoopDat#iac_state{emergency=0, t3=undefined}}; |
| aligned(stop, LoopDat) -> |
| % Stop T3 |
| timer:cancel(LoopDat#iac_state.t3), |
| % cancel Emergency |
| {next_state, idle, LoopDat#iac_state{emergency=0, t3=undefined}}; |
| aligned({timer_expired, t3}, LoopDat) -> |
| % Send alignment not possible |
| send_to_lsc(alignment_not_possible, LoopDat), |
| % cancel emergency |
| {next_state, idle, LoopDat#iac_state{emergency=0}}. |
| |
| |
| %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
| % STATE "proving" |
| %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
| fig9_4(LoopDat) -> |
| % send Stop to AERM |
| send_to_aerm(stop, LoopDat), |
| % cancel emergency |
| {next_state, idle, LoopDat#iac_state{emergency=0}}. |
| |
| fig9_5(LoopDat) -> |
| % send Start to AERM |
| send_to_aerm(start, LoopDat), |
| % cancel further proving |
| % start T4 |
| T4tout = LoopDat#iac_state.t4_timeout, |
| {ok, T4} = timer:apply_after(T4tout, gen_fsm, send_event, |
| [self(), {timer_expired, t4}]), |
| {next_state, proving, LoopDat#iac_state{t4=T4, further_prov=0}}. |
| |
| prov_emerg_or_sie(LoopDat) -> |
| % stop T4 |
| timer:cancel(LoopDat#iac_state.t4), |
| % Set T4 to Pe |
| T4tout = LoopDat#iac_state.t4_timeout_pe, |
| % Send stop to AERM |
| send_to_aerm(stop, LoopDat), |
| % Send 'set ti to tie' to AERM |
| send_to_aerm(set_ti_to_tie, LoopDat), |
| fig9_5(LoopDat#iac_state{t4_timeout=T4tout, t4=undefined}). |
| |
| |
| proving(expires, LoopDat) -> |
| % alignment complete |
| {next_state, idle, LoopDat}; |
| proving(si_e, LoopDat) -> |
| ToutPE = LoopDat#iac_state.t4_timeout_pe, |
| case LoopDat#iac_state.t4_timeout of |
| ToutPE -> |
| {next_state, proving, LoopDat}; |
| _ -> |
| prov_emerg_or_sie(LoopDat) |
| end; |
| proving(emergency, LoopDat) -> |
| prov_emerg_or_sie(LoopDat); |
| proving(stop, LoopDat) -> |
| % stop T4 |
| timer:cancel(LoopDat#iac_state.t4), |
| fig9_4(LoopDat); |
| proving(si_os, LoopDat) -> |
| % stop T4 |
| timer:cancel(LoopDat#iac_state.t4), |
| % Send alignment not possible to LSC |
| send_to_lsc(alignment_not_possible, LoopDat), |
| fig9_4(LoopDat); |
| proving(high_err_rate, LoopDat) -> |
| % alignment not possible |
| {next_state, idle, LoopDat}; |
| proving(sio, LoopDat) -> |
| % stop T4 |
| timer:cancel(LoopDat#iac_state.t4), |
| % send Stop to AERM |
| send_to_aerm(stop, LoopDat), |
| % start T3 |
| T3tout = LoopDat#iac_state.t3_timeout, |
| {ok, T3} = timer:apply_after(T3tout, gen_fsm, send_event, |
| [self(), {timer_expired, t3}]), |
| {next_state, aligned, LoopDat#iac_state{t3=T3, t4=undefined}}; |
| proving(What, LoopDat) when What == correct_su; What == si_n -> |
| case LoopDat#iac_state.further_prov of |
| 1 -> |
| % stop T4 |
| timer:cancel(LoopDat#iac_state.t4), |
| fig9_5(LoopDat); |
| _ -> |
| {next_state, proving, LoopDat} |
| end; |
| proving({timer_expired, t4}, LoopDat) -> |
| % check if we are further proving, if yes, call fig9_5 |
| case LoopDat#iac_state.further_prov of |
| 1 -> |
| fig9_5(LoopDat); |
| _ -> |
| % send 'aligment complete' to LSC |
| send_to_lsc(alignment_complete, LoopDat), |
| fig9_4(LoopDat) |
| end; |
| proving(abort_proving, LoopDat) -> |
| % Cp := Cp + 1 |
| Cp = LoopDat#iac_state.cp, |
| LoopDat2 = LoopDat#iac_state{cp = Cp + 1}, |
| case Cp + 1 of |
| 5 -> |
| % send 'alignment not possible' to LSC |
| send_to_lsc(alignment_not_possible, LoopDat), |
| % stop T4 |
| timer:cancel(LoopDat#iac_state.t4), |
| fig9_4(LoopDat2); |
| _ -> |
| % mark further proving |
| {next_state, proving, LoopDat2#iac_state{further_prov=1}} |
| end. |
| |
| |
| %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
| % helper functions |
| %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
| send_to_lsc(What, #iac_state{lsc_pid = Lsc}) -> |
| gen_fsm:send_event(Lsc, What). |
| |
| send_to_aerm(What, #iac_state{aerm_pid = Aerm}) -> |
| Aerm ! {iac_aerm, What}. |
| |
| send_to_txc(What, #iac_state{txc_pid = Txc}) -> |
| Txc ! {iac_txc, What}. |