Harald Welte | b668988 | 2012-01-16 16:00:45 +0100 | [diff] [blame] | 1 | % MTP2 Initial Alignment Control according to Q.703 Figure 4 / Figure 9 |
| 2 | |
| 3 | % (C) 2011-2012 by Harald Welte <laforge@gnumonks.org> |
| 4 | % |
| 5 | % All Rights Reserved |
| 6 | % |
| 7 | % This program is free software; you can redistribute it and/or modify |
| 8 | % it under the terms of the GNU Affero General Public License as |
| 9 | % published by the Free Software Foundation; either version 3 of the |
| 10 | % License, or (at your option) any later version. |
| 11 | % |
| 12 | % This program is distributed in the hope that it will be useful, |
| 13 | % but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | % MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 15 | % GNU General Public License for more details. |
| 16 | % |
| 17 | % You should have received a copy of the GNU Affero General Public License |
| 18 | % along with this program. If not, see <http://www.gnu.org/licenses/>. |
| 19 | |
| 20 | -module(mtp2_iac). |
| 21 | -author('Harald Welte <laforge@gnumonks.org>'). |
| 22 | -behaviour(gen_fsm). |
| 23 | |
| 24 | % gen_fsm exports |
| 25 | -export([init/1, terminate/3, code_change/4, handle_event/3, handle_info/3]). |
| 26 | |
| 27 | % states in this FSM |
| 28 | -export([idle/2, not_aligned/2, aligned/2, proving/2]). |
| 29 | |
| 30 | % Timeouts in milliseconds According to Q.703 / Section 12.3 |
| 31 | -define(M2PA_T1_DEF, 50000). |
| 32 | -define(M2PA_T2_DEF, 150000). |
| 33 | -define(M2PA_T3_DEF, 2000). |
| 34 | -define(M2PA_T4N_DEF, 8200). |
| 35 | -define(M2PA_T4E_DEF, 500). |
| 36 | |
| 37 | -record(iac_state, { |
| 38 | t2_timeout, |
| 39 | t3_timeout, |
| 40 | t4_timeout, |
| 41 | t4_timeout_pn, |
| 42 | t4_timeout_pe, |
| 43 | t2, t3, t4, |
| 44 | emergency, |
| 45 | cp, |
| 46 | further_prov, |
| 47 | lsc_pid, |
| 48 | aerm_pid, |
| 49 | txc_pid |
| 50 | }). |
| 51 | |
| 52 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
| 53 | % gen_fsm callbacks |
| 54 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
| 55 | |
| 56 | init([Lsc, Aerm, Txc]) -> |
| 57 | IacState = #iac_state{t2_timeout = ?M2PA_T2_DEF, |
| 58 | t3_timeout = ?M2PA_T3_DEF, |
| 59 | t4_timeout_pn = ?M2PA_T4N_DEF, |
| 60 | t4_timeout_pe = ?M2PA_T4E_DEF, |
| 61 | emergency = 0, |
| 62 | cp = 0, |
| 63 | further_prov = 1, |
| 64 | lsc_pid = Lsc, |
| 65 | aerm_pid = Aerm, |
| 66 | txc_pid = Txc}, |
| 67 | {ok, idle, IacState}. |
| 68 | |
| 69 | terminate(Reason, State, _LoopDat) -> |
| 70 | io:format("Terminating ~p in State ~p (Reason: ~p)~n", |
| 71 | [?MODULE, State, Reason]), |
| 72 | ok. |
| 73 | |
| 74 | code_change(_OldVsn, StateName, LoopDat, _Extra) -> |
| 75 | {ok, StateName, LoopDat}. |
| 76 | |
| 77 | handle_event(Event, State, LoopDat) -> |
| 78 | io:format("Unknown Event ~p in state ~p~n", [Event, State]), |
| 79 | {next_state, State, LoopDat}. |
| 80 | |
| 81 | |
| 82 | handle_info(Info, State, LoopDat) -> |
| 83 | io:format("Unknown Info ~p in state ~p~n", [Info, State]), |
| 84 | {next_state, State, LoopDat}. |
| 85 | |
| 86 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
| 87 | % STATE "idle" |
| 88 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
| 89 | |
| 90 | idle(start, LoopDat) -> |
| 91 | % send sio |
| 92 | send_to_txc(si_o, LoopDat), |
| 93 | % start timer |
| 94 | T2tout = LoopDat#iac_state.t2_timeout, |
| 95 | {ok, T2} = timer:apply_after(T2tout, gen_fsm, send_event, |
| 96 | [self(), {timer_expired, t2}]), |
| 97 | {next_state, not_aligned, LoopDat#iac_state{t2 = T2}}; |
| 98 | idle(emergency, LoopDat) -> |
| 99 | % mark emergency |
| 100 | {next_state, idle, LoopDat#iac_state{emergency = 1}}. |
| 101 | |
| 102 | |
| 103 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
| 104 | % STATE "not aligned" |
| 105 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
| 106 | |
| 107 | not_aligned(stop, LoopDat) -> |
| 108 | % stop T2 |
| 109 | timer:cancel(LoopDat#iac_state.t2), |
| 110 | % cancel emergency |
| 111 | {next_state, idle, LoopDat#iac_state{emergency=0}}; |
| 112 | not_aligned(si_e, LoopDat) -> |
| 113 | % stop T2 |
| 114 | timer:cancel(LoopDat#iac_state.t2), |
| 115 | T4tout = LoopDat#iac_state.t4_timeout_pe, |
| 116 | % send SIE or SIN |
| 117 | case LoopDat#iac_state.emergency of |
| 118 | 0 -> |
| 119 | Send = si_n; |
| 120 | _ -> |
| 121 | Send = si_e |
| 122 | end, |
| 123 | send_to_txc(Send, LoopDat), |
| 124 | % start T3 |
| 125 | T3tout = LoopDat#iac_state.t3_timeout, |
| 126 | {ok, T3} = timer:apply_after(T3tout, gen_fsm, send_event, |
| 127 | [self(), {timer_expired, t3}]), |
| 128 | {next_state, aligned, LoopDat#iac_state{t3 = T3, t2 = undefined, t4_timeout = T4tout}}; |
| 129 | not_aligned(What, LoopDat) when What == si_o; What == si_n -> |
| 130 | % stop T2 |
| 131 | timer:cancel(LoopDat#iac_state.t2), |
| 132 | % send SIE or SIN |
| 133 | case LoopDat#iac_state.emergency of |
| 134 | 0 -> |
| 135 | T4tout = LoopDat#iac_state.t4_timeout_pn, |
| 136 | Send = si_n; |
| 137 | _ -> |
| 138 | T4tout = LoopDat#iac_state.t4_timeout_pe, |
| 139 | Send = si_e |
| 140 | end, |
| 141 | send_to_txc(Send, LoopDat), |
| 142 | T3tout = LoopDat#iac_state.t3_timeout, |
| 143 | {ok, T3} = timer:apply_after(T3tout, gen_fsm, send_event, |
| 144 | [self(), {timer_expired, t3}]), |
| 145 | {next_state, aligned, LoopDat#iac_state{t3 = T3, t2 = undefined, t4_timeout = T4tout}}; |
| 146 | not_aligned(emergency, LoopDat) -> |
| 147 | % mark emergency |
| 148 | {next_state, not_aligned, LoopDat#iac_state{emergency=1}}; |
Harald Welte | 4d08a71 | 2012-01-19 22:30:17 +0100 | [diff] [blame^] | 149 | not_aligned(si_os, LoopDat) -> |
| 150 | % ignore SIOS in this state, as some implementations (notably |
| 151 | % yate) seem to send it in violation of the spec |
| 152 | {next_state, not_aligned, LoopDat}; |
Harald Welte | b668988 | 2012-01-16 16:00:45 +0100 | [diff] [blame] | 153 | not_aligned({timer_expired, t2}, LoopDat) -> |
| 154 | % send 'alignment not possible' to LSC |
| 155 | send_to_lsc(alignment_not_possible, LoopDat), |
| 156 | % stop emergency |
| 157 | {next_state, idle, LoopDat#iac_state{emergency=0}}. |
| 158 | |
| 159 | |
| 160 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
| 161 | % STATE "aligned" |
| 162 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
| 163 | aligned(What, LoopDat) when What == si_n; What == si_e -> |
| 164 | case What of |
| 165 | si_e -> |
| 166 | % set T4 to Pe |
| 167 | T4tout = LoopDat#iac_state.t4_timeout_pe; |
| 168 | _ -> |
| 169 | T4tout = LoopDat#iac_state.t4_timeout_pn |
| 170 | end, |
| 171 | % stop T3 |
| 172 | timer:cancel(LoopDat#iac_state.t3), |
| 173 | ToutPE = LoopDat#iac_state.t4_timeout_pe, |
| 174 | case T4tout of |
| 175 | ToutPE -> |
| 176 | % set i to ie IAC->AERM |
| 177 | send_to_aerm(set_i_to_ie, LoopDat); |
| 178 | _ -> |
| 179 | ok |
| 180 | end, |
| 181 | % send Start to AERM |
| 182 | send_to_aerm(start, LoopDat), |
| 183 | % start T4 |
| 184 | io:format("trying to start T4, T4tout=~p~n", [T4tout]), |
| 185 | {ok, T4} = timer:apply_after(T4tout, gen_fsm, send_event, |
| 186 | [self(), {timer_expired, t4}]), |
| 187 | % Cp := 0 |
| 188 | % cancel further proving? |
| 189 | LoopDat2 = LoopDat#iac_state{t4 = T4, t4_timeout = T4tout, |
| 190 | cp = 0, further_prov = 0}, |
| 191 | {next_state, proving, LoopDat2}; |
| 192 | aligned(emergency, LoopDat) -> |
| 193 | % Send SIE |
| 194 | send_to_txc(si_e, LoopDat), |
| 195 | T4tout = LoopDat#iac_state.t4_timeout_pe, |
| 196 | {next_State, aligned, LoopDat#iac_state{t4_timeout = T4tout}}; |
| 197 | aligned(si_os, LoopDat) -> |
| 198 | % Send alignment not possible |
| 199 | send_to_lsc(alignment_not_possible, LoopDat), |
| 200 | % stop T3 |
| 201 | timer:cancel(LoopDat#iac_state.t3), |
| 202 | {next_state, idle, LoopDat#iac_state{emergency=0, t3=undefined}}; |
| 203 | aligned(stop, LoopDat) -> |
| 204 | % Stop T3 |
| 205 | timer:cancel(LoopDat#iac_state.t3), |
| 206 | % cancel Emergency |
| 207 | {next_state, idle, LoopDat#iac_state{emergency=0, t3=undefined}}; |
| 208 | aligned({timer_expired, t3}, LoopDat) -> |
| 209 | % Send alignment not possible |
| 210 | send_to_lsc(alignment_not_possible, LoopDat), |
| 211 | % cancel emergency |
| 212 | {next_state, idle, LoopDat#iac_state{emergency=0}}. |
| 213 | |
| 214 | |
| 215 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
| 216 | % STATE "proving" |
| 217 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
| 218 | fig9_4(LoopDat) -> |
| 219 | % send Stop to AERM |
| 220 | send_to_aerm(stop, LoopDat), |
| 221 | % cancel emergency |
| 222 | {next_state, idle, LoopDat#iac_state{emergency=0}}. |
| 223 | |
| 224 | fig9_5(LoopDat) -> |
| 225 | % send Start to AERM |
| 226 | send_to_aerm(start, LoopDat), |
| 227 | % cancel further proving |
| 228 | % start T4 |
| 229 | T4tout = LoopDat#iac_state.t4_timeout, |
| 230 | {ok, T4} = timer:apply_after(T4tout, gen_fsm, send_event, |
| 231 | [self(), {timer_expired, t4}]), |
| 232 | {next_state, proving, LoopDat#iac_state{t4=T4, further_prov=0}}. |
| 233 | |
| 234 | prov_emerg_or_sie(LoopDat) -> |
| 235 | % stop T4 |
| 236 | timer:cancel(LoopDat#iac_state.t4), |
| 237 | % Set T4 to Pe |
| 238 | T4tout = LoopDat#iac_state.t4_timeout_pe, |
| 239 | % Send stop to AERM |
| 240 | send_to_aerm(stop, LoopDat), |
| 241 | % Send 'set ti to tie' to AERM |
| 242 | send_to_aerm(set_ti_to_tie, LoopDat), |
| 243 | fig9_5(LoopDat#iac_state{t4_timeout=T4tout, t4=undefined}). |
| 244 | |
| 245 | |
| 246 | proving(expires, LoopDat) -> |
| 247 | % alignment complete |
| 248 | {next_state, idle, LoopDat}; |
| 249 | proving(si_e, LoopDat) -> |
| 250 | ToutPE = LoopDat#iac_state.t4_timeout_pe, |
| 251 | case LoopDat#iac_state.t4_timeout of |
| 252 | ToutPE -> |
| 253 | {next_state, proving, LoopDat}; |
| 254 | _ -> |
| 255 | prov_emerg_or_sie(LoopDat) |
| 256 | end; |
| 257 | proving(emergency, LoopDat) -> |
| 258 | prov_emerg_or_sie(LoopDat); |
| 259 | proving(stop, LoopDat) -> |
| 260 | % stop T4 |
| 261 | timer:cancel(LoopDat#iac_state.t4), |
| 262 | fig9_4(LoopDat); |
| 263 | proving(si_os, LoopDat) -> |
| 264 | % stop T4 |
| 265 | timer:cancel(LoopDat#iac_state.t4), |
| 266 | % Send alignment not possible to LSC |
| 267 | send_to_lsc(alignment_not_possible, LoopDat), |
| 268 | fig9_4(LoopDat); |
| 269 | proving(high_err_rate, LoopDat) -> |
| 270 | % alignment not possible |
| 271 | {next_state, idle, LoopDat}; |
| 272 | proving(sio, LoopDat) -> |
| 273 | % stop T4 |
| 274 | timer:cancel(LoopDat#iac_state.t4), |
| 275 | % send Stop to AERM |
| 276 | send_to_aerm(stop, LoopDat), |
| 277 | % start T3 |
| 278 | T3tout = LoopDat#iac_state.t3_timeout, |
| 279 | {ok, T3} = timer:apply_after(T3tout, gen_fsm, send_event, |
| 280 | [self(), {timer_expired, t3}]), |
| 281 | {next_state, aligned, LoopDat#iac_state{t3=T3, t4=undefined}}; |
| 282 | proving(What, LoopDat) when What == correct_su; What == si_n -> |
| 283 | case LoopDat#iac_state.further_prov of |
| 284 | 1 -> |
| 285 | % stop T4 |
| 286 | timer:cancel(LoopDat#iac_state.t4), |
| 287 | fig9_5(LoopDat); |
| 288 | _ -> |
| 289 | {next_state, proving, LoopDat} |
| 290 | end; |
| 291 | proving({timer_expired, t4}, LoopDat) -> |
| 292 | % check if we are further proving, if yes, call fig9_5 |
| 293 | case LoopDat#iac_state.further_prov of |
| 294 | 1 -> |
| 295 | fig9_5(LoopDat); |
| 296 | _ -> |
| 297 | % send 'aligment complete' to LSC |
| 298 | send_to_lsc(alignment_complete, LoopDat), |
| 299 | fig9_4(LoopDat) |
| 300 | end; |
| 301 | proving(abort_proving, LoopDat) -> |
| 302 | % Cp := Cp + 1 |
| 303 | Cp = LoopDat#iac_state.cp, |
| 304 | LoopDat2 = LoopDat#iac_state{cp = Cp + 1}, |
| 305 | case Cp + 1 of |
| 306 | 5 -> |
| 307 | % send 'alignment not possible' to LSC |
| 308 | send_to_lsc(alignment_not_possible, LoopDat), |
| 309 | % stop T4 |
| 310 | timer:cancel(LoopDat#iac_state.t4), |
| 311 | fig9_4(LoopDat2); |
| 312 | _ -> |
| 313 | % mark further proving |
| 314 | {next_state, proving, LoopDat2#iac_state{further_prov=1}} |
| 315 | end. |
| 316 | |
| 317 | |
| 318 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
| 319 | % helper functions |
| 320 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
| 321 | send_to_lsc(What, #iac_state{lsc_pid = Lsc}) -> |
| 322 | gen_fsm:send_event(Lsc, What). |
| 323 | |
| 324 | send_to_aerm(What, #iac_state{aerm_pid = Aerm}) -> |
| 325 | Aerm ! {iac_aerm, What}. |
| 326 | |
| 327 | send_to_txc(What, #iac_state{txc_pid = Txc}) -> |
| 328 | Txc ! {iac_txc, What}. |