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/>. |
Harald Welte | f8bf032 | 2012-04-16 13:10:47 +0200 | [diff] [blame] | 19 | % |
| 20 | % Additional Permission under GNU AGPL version 3 section 7: |
| 21 | % |
| 22 | % If you modify this Program, or any covered work, by linking or |
| 23 | % combining it with runtime libraries of Erlang/OTP as released by |
| 24 | % Ericsson on http://www.erlang.org (or a modified version of these |
| 25 | % libraries), containing parts covered by the terms of the Erlang Public |
| 26 | % License (http://www.erlang.org/EPLICENSE), the licensors of this |
| 27 | % Program grant you additional permission to convey the resulting work |
| 28 | % without the need to license the runtime libraries of Erlang/OTP under |
| 29 | % the GNU Affero General Public License. Corresponding Source for a |
| 30 | % non-source form of such a combination shall include the source code |
| 31 | % for the parts of the runtime libraries of Erlang/OTP used as well as |
| 32 | % that of the covered work. |
Harald Welte | b668988 | 2012-01-16 16:00:45 +0100 | [diff] [blame] | 33 | |
| 34 | -module(mtp2_iac). |
| 35 | -author('Harald Welte <laforge@gnumonks.org>'). |
| 36 | -behaviour(gen_fsm). |
| 37 | |
| 38 | % gen_fsm exports |
| 39 | -export([init/1, terminate/3, code_change/4, handle_event/3, handle_info/3]). |
| 40 | |
| 41 | % states in this FSM |
| 42 | -export([idle/2, not_aligned/2, aligned/2, proving/2]). |
| 43 | |
| 44 | % Timeouts in milliseconds According to Q.703 / Section 12.3 |
| 45 | -define(M2PA_T1_DEF, 50000). |
| 46 | -define(M2PA_T2_DEF, 150000). |
| 47 | -define(M2PA_T3_DEF, 2000). |
| 48 | -define(M2PA_T4N_DEF, 8200). |
| 49 | -define(M2PA_T4E_DEF, 500). |
| 50 | |
| 51 | -record(iac_state, { |
| 52 | t2_timeout, |
| 53 | t3_timeout, |
| 54 | t4_timeout, |
| 55 | t4_timeout_pn, |
| 56 | t4_timeout_pe, |
| 57 | t2, t3, t4, |
| 58 | emergency, |
| 59 | cp, |
| 60 | further_prov, |
| 61 | lsc_pid, |
| 62 | aerm_pid, |
| 63 | txc_pid |
| 64 | }). |
| 65 | |
| 66 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
| 67 | % gen_fsm callbacks |
| 68 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
| 69 | |
| 70 | init([Lsc, Aerm, Txc]) -> |
| 71 | IacState = #iac_state{t2_timeout = ?M2PA_T2_DEF, |
| 72 | t3_timeout = ?M2PA_T3_DEF, |
| 73 | t4_timeout_pn = ?M2PA_T4N_DEF, |
| 74 | t4_timeout_pe = ?M2PA_T4E_DEF, |
| 75 | emergency = 0, |
| 76 | cp = 0, |
| 77 | further_prov = 1, |
| 78 | lsc_pid = Lsc, |
| 79 | aerm_pid = Aerm, |
| 80 | txc_pid = Txc}, |
| 81 | {ok, idle, IacState}. |
| 82 | |
| 83 | terminate(Reason, State, _LoopDat) -> |
| 84 | io:format("Terminating ~p in State ~p (Reason: ~p)~n", |
| 85 | [?MODULE, State, Reason]), |
| 86 | ok. |
| 87 | |
| 88 | code_change(_OldVsn, StateName, LoopDat, _Extra) -> |
| 89 | {ok, StateName, LoopDat}. |
| 90 | |
| 91 | handle_event(Event, State, LoopDat) -> |
| 92 | io:format("Unknown Event ~p in state ~p~n", [Event, State]), |
| 93 | {next_state, State, LoopDat}. |
| 94 | |
| 95 | |
| 96 | handle_info(Info, State, LoopDat) -> |
| 97 | io:format("Unknown Info ~p in state ~p~n", [Info, State]), |
| 98 | {next_state, State, LoopDat}. |
| 99 | |
| 100 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
| 101 | % STATE "idle" |
| 102 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
| 103 | |
| 104 | idle(start, LoopDat) -> |
| 105 | % send sio |
| 106 | send_to_txc(si_o, LoopDat), |
| 107 | % start timer |
| 108 | T2tout = LoopDat#iac_state.t2_timeout, |
| 109 | {ok, T2} = timer:apply_after(T2tout, gen_fsm, send_event, |
| 110 | [self(), {timer_expired, t2}]), |
| 111 | {next_state, not_aligned, LoopDat#iac_state{t2 = T2}}; |
| 112 | idle(emergency, LoopDat) -> |
| 113 | % mark emergency |
| 114 | {next_state, idle, LoopDat#iac_state{emergency = 1}}. |
| 115 | |
| 116 | |
| 117 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
| 118 | % STATE "not aligned" |
| 119 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
| 120 | |
| 121 | not_aligned(stop, LoopDat) -> |
| 122 | % stop T2 |
| 123 | timer:cancel(LoopDat#iac_state.t2), |
| 124 | % cancel emergency |
| 125 | {next_state, idle, LoopDat#iac_state{emergency=0}}; |
| 126 | not_aligned(si_e, LoopDat) -> |
| 127 | % stop T2 |
| 128 | timer:cancel(LoopDat#iac_state.t2), |
| 129 | T4tout = LoopDat#iac_state.t4_timeout_pe, |
| 130 | % send SIE or SIN |
| 131 | case LoopDat#iac_state.emergency of |
| 132 | 0 -> |
| 133 | Send = si_n; |
| 134 | _ -> |
| 135 | Send = si_e |
| 136 | end, |
| 137 | send_to_txc(Send, LoopDat), |
| 138 | % start T3 |
| 139 | T3tout = LoopDat#iac_state.t3_timeout, |
| 140 | {ok, T3} = timer:apply_after(T3tout, gen_fsm, send_event, |
| 141 | [self(), {timer_expired, t3}]), |
| 142 | {next_state, aligned, LoopDat#iac_state{t3 = T3, t2 = undefined, t4_timeout = T4tout}}; |
| 143 | not_aligned(What, LoopDat) when What == si_o; What == si_n -> |
| 144 | % stop T2 |
| 145 | timer:cancel(LoopDat#iac_state.t2), |
| 146 | % send SIE or SIN |
| 147 | case LoopDat#iac_state.emergency of |
| 148 | 0 -> |
| 149 | T4tout = LoopDat#iac_state.t4_timeout_pn, |
| 150 | Send = si_n; |
| 151 | _ -> |
| 152 | T4tout = LoopDat#iac_state.t4_timeout_pe, |
| 153 | Send = si_e |
| 154 | end, |
| 155 | send_to_txc(Send, LoopDat), |
| 156 | T3tout = LoopDat#iac_state.t3_timeout, |
| 157 | {ok, T3} = timer:apply_after(T3tout, gen_fsm, send_event, |
| 158 | [self(), {timer_expired, t3}]), |
| 159 | {next_state, aligned, LoopDat#iac_state{t3 = T3, t2 = undefined, t4_timeout = T4tout}}; |
| 160 | not_aligned(emergency, LoopDat) -> |
| 161 | % mark emergency |
| 162 | {next_state, not_aligned, LoopDat#iac_state{emergency=1}}; |
Harald Welte | 4d08a71 | 2012-01-19 22:30:17 +0100 | [diff] [blame] | 163 | not_aligned(si_os, LoopDat) -> |
| 164 | % ignore SIOS in this state, as some implementations (notably |
| 165 | % yate) seem to send it in violation of the spec |
| 166 | {next_state, not_aligned, LoopDat}; |
Harald Welte | b668988 | 2012-01-16 16:00:45 +0100 | [diff] [blame] | 167 | not_aligned({timer_expired, t2}, LoopDat) -> |
| 168 | % send 'alignment not possible' to LSC |
| 169 | send_to_lsc(alignment_not_possible, LoopDat), |
| 170 | % stop emergency |
| 171 | {next_state, idle, LoopDat#iac_state{emergency=0}}. |
| 172 | |
| 173 | |
| 174 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
| 175 | % STATE "aligned" |
| 176 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
| 177 | aligned(What, LoopDat) when What == si_n; What == si_e -> |
| 178 | case What of |
| 179 | si_e -> |
| 180 | % set T4 to Pe |
| 181 | T4tout = LoopDat#iac_state.t4_timeout_pe; |
| 182 | _ -> |
| 183 | T4tout = LoopDat#iac_state.t4_timeout_pn |
| 184 | end, |
| 185 | % stop T3 |
| 186 | timer:cancel(LoopDat#iac_state.t3), |
| 187 | ToutPE = LoopDat#iac_state.t4_timeout_pe, |
| 188 | case T4tout of |
| 189 | ToutPE -> |
| 190 | % set i to ie IAC->AERM |
| 191 | send_to_aerm(set_i_to_ie, LoopDat); |
| 192 | _ -> |
| 193 | ok |
| 194 | end, |
| 195 | % send Start to AERM |
| 196 | send_to_aerm(start, LoopDat), |
| 197 | % start T4 |
Harald Welte | b668988 | 2012-01-16 16:00:45 +0100 | [diff] [blame] | 198 | {ok, T4} = timer:apply_after(T4tout, gen_fsm, send_event, |
| 199 | [self(), {timer_expired, t4}]), |
| 200 | % Cp := 0 |
| 201 | % cancel further proving? |
| 202 | LoopDat2 = LoopDat#iac_state{t4 = T4, t4_timeout = T4tout, |
| 203 | cp = 0, further_prov = 0}, |
| 204 | {next_state, proving, LoopDat2}; |
| 205 | aligned(emergency, LoopDat) -> |
| 206 | % Send SIE |
| 207 | send_to_txc(si_e, LoopDat), |
| 208 | T4tout = LoopDat#iac_state.t4_timeout_pe, |
| 209 | {next_State, aligned, LoopDat#iac_state{t4_timeout = T4tout}}; |
| 210 | aligned(si_os, LoopDat) -> |
| 211 | % Send alignment not possible |
| 212 | send_to_lsc(alignment_not_possible, LoopDat), |
| 213 | % stop T3 |
| 214 | timer:cancel(LoopDat#iac_state.t3), |
| 215 | {next_state, idle, LoopDat#iac_state{emergency=0, t3=undefined}}; |
| 216 | aligned(stop, LoopDat) -> |
| 217 | % Stop T3 |
| 218 | timer:cancel(LoopDat#iac_state.t3), |
| 219 | % cancel Emergency |
| 220 | {next_state, idle, LoopDat#iac_state{emergency=0, t3=undefined}}; |
| 221 | aligned({timer_expired, t3}, LoopDat) -> |
| 222 | % Send alignment not possible |
| 223 | send_to_lsc(alignment_not_possible, LoopDat), |
| 224 | % cancel emergency |
| 225 | {next_state, idle, LoopDat#iac_state{emergency=0}}. |
| 226 | |
| 227 | |
| 228 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
| 229 | % STATE "proving" |
| 230 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
| 231 | fig9_4(LoopDat) -> |
| 232 | % send Stop to AERM |
| 233 | send_to_aerm(stop, LoopDat), |
| 234 | % cancel emergency |
| 235 | {next_state, idle, LoopDat#iac_state{emergency=0}}. |
| 236 | |
| 237 | fig9_5(LoopDat) -> |
| 238 | % send Start to AERM |
| 239 | send_to_aerm(start, LoopDat), |
| 240 | % cancel further proving |
| 241 | % start T4 |
| 242 | T4tout = LoopDat#iac_state.t4_timeout, |
| 243 | {ok, T4} = timer:apply_after(T4tout, gen_fsm, send_event, |
| 244 | [self(), {timer_expired, t4}]), |
| 245 | {next_state, proving, LoopDat#iac_state{t4=T4, further_prov=0}}. |
| 246 | |
| 247 | prov_emerg_or_sie(LoopDat) -> |
| 248 | % stop T4 |
| 249 | timer:cancel(LoopDat#iac_state.t4), |
| 250 | % Set T4 to Pe |
| 251 | T4tout = LoopDat#iac_state.t4_timeout_pe, |
| 252 | % Send stop to AERM |
| 253 | send_to_aerm(stop, LoopDat), |
| 254 | % Send 'set ti to tie' to AERM |
| 255 | send_to_aerm(set_ti_to_tie, LoopDat), |
| 256 | fig9_5(LoopDat#iac_state{t4_timeout=T4tout, t4=undefined}). |
| 257 | |
| 258 | |
| 259 | proving(expires, LoopDat) -> |
| 260 | % alignment complete |
| 261 | {next_state, idle, LoopDat}; |
| 262 | proving(si_e, LoopDat) -> |
| 263 | ToutPE = LoopDat#iac_state.t4_timeout_pe, |
| 264 | case LoopDat#iac_state.t4_timeout of |
| 265 | ToutPE -> |
| 266 | {next_state, proving, LoopDat}; |
| 267 | _ -> |
| 268 | prov_emerg_or_sie(LoopDat) |
| 269 | end; |
| 270 | proving(emergency, LoopDat) -> |
| 271 | prov_emerg_or_sie(LoopDat); |
| 272 | proving(stop, LoopDat) -> |
| 273 | % stop T4 |
| 274 | timer:cancel(LoopDat#iac_state.t4), |
| 275 | fig9_4(LoopDat); |
| 276 | proving(si_os, LoopDat) -> |
| 277 | % stop T4 |
| 278 | timer:cancel(LoopDat#iac_state.t4), |
| 279 | % Send alignment not possible to LSC |
| 280 | send_to_lsc(alignment_not_possible, LoopDat), |
| 281 | fig9_4(LoopDat); |
| 282 | proving(high_err_rate, LoopDat) -> |
| 283 | % alignment not possible |
| 284 | {next_state, idle, LoopDat}; |
| 285 | proving(sio, LoopDat) -> |
| 286 | % stop T4 |
| 287 | timer:cancel(LoopDat#iac_state.t4), |
| 288 | % send Stop to AERM |
| 289 | send_to_aerm(stop, LoopDat), |
| 290 | % start T3 |
| 291 | T3tout = LoopDat#iac_state.t3_timeout, |
| 292 | {ok, T3} = timer:apply_after(T3tout, gen_fsm, send_event, |
| 293 | [self(), {timer_expired, t3}]), |
| 294 | {next_state, aligned, LoopDat#iac_state{t3=T3, t4=undefined}}; |
| 295 | proving(What, LoopDat) when What == correct_su; What == si_n -> |
| 296 | case LoopDat#iac_state.further_prov of |
| 297 | 1 -> |
| 298 | % stop T4 |
| 299 | timer:cancel(LoopDat#iac_state.t4), |
| 300 | fig9_5(LoopDat); |
| 301 | _ -> |
| 302 | {next_state, proving, LoopDat} |
| 303 | end; |
| 304 | proving({timer_expired, t4}, LoopDat) -> |
| 305 | % check if we are further proving, if yes, call fig9_5 |
| 306 | case LoopDat#iac_state.further_prov of |
| 307 | 1 -> |
| 308 | fig9_5(LoopDat); |
| 309 | _ -> |
| 310 | % send 'aligment complete' to LSC |
| 311 | send_to_lsc(alignment_complete, LoopDat), |
| 312 | fig9_4(LoopDat) |
| 313 | end; |
Harald Welte | b668988 | 2012-01-16 16:00:45 +0100 | [diff] [blame] | 314 | proving(abort_proving, LoopDat) -> |
| 315 | % Cp := Cp + 1 |
| 316 | Cp = LoopDat#iac_state.cp, |
| 317 | LoopDat2 = LoopDat#iac_state{cp = Cp + 1}, |
| 318 | case Cp + 1 of |
| 319 | 5 -> |
| 320 | % send 'alignment not possible' to LSC |
| 321 | send_to_lsc(alignment_not_possible, LoopDat), |
| 322 | % stop T4 |
| 323 | timer:cancel(LoopDat#iac_state.t4), |
| 324 | fig9_4(LoopDat2); |
| 325 | _ -> |
| 326 | % mark further proving |
| 327 | {next_state, proving, LoopDat2#iac_state{further_prov=1}} |
| 328 | end. |
| 329 | |
| 330 | |
| 331 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
| 332 | % helper functions |
| 333 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
| 334 | send_to_lsc(What, #iac_state{lsc_pid = Lsc}) -> |
| 335 | gen_fsm:send_event(Lsc, What). |
| 336 | |
| 337 | send_to_aerm(What, #iac_state{aerm_pid = Aerm}) -> |
| 338 | Aerm ! {iac_aerm, What}. |
| 339 | |
| 340 | send_to_txc(What, #iac_state{txc_pid = Txc}) -> |
| 341 | Txc ! {iac_txc, What}. |