Harald Welte | 26bdef2 | 2012-01-16 22:22:17 +0100 | [diff] [blame] | 1 | % M2PA in accordance with RFC4165 (http://tools.ietf.org/html/rfc4665) |
| 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(sctp_m2pa). |
| 21 | -author('Harald Welte <laforge@gnumonks.org>'). |
| 22 | -behaviour(sctp_core). |
| 23 | |
| 24 | -include_lib("kernel/include/inet_sctp.hrl"). |
| 25 | -include("osmo_util.hrl"). |
| 26 | -include("m2pa.hrl"). |
| 27 | |
| 28 | -export([init/1, terminate/3, code_change/4, handle_event/3, handle_info/3]). |
| 29 | |
Harald Welte | 91b7965 | 2012-01-17 10:12:34 +0100 | [diff] [blame^] | 30 | -export([rx_sctp/4, mtp_xfer/2, state_change/3, prim_up/3]). |
Harald Welte | 26bdef2 | 2012-01-16 22:22:17 +0100 | [diff] [blame] | 31 | |
| 32 | -record(m2pa_state, { |
| 33 | last_bsn_received, |
| 34 | last_fsn_sent, |
| 35 | lsc_pid, |
| 36 | iac_pid |
| 37 | }). |
| 38 | |
| 39 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
| 40 | % gen_fsm callbacks |
| 41 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
| 42 | |
| 43 | init(_InitOpts) -> |
| 44 | % start MTP2 IAC FSM pointing LSC, AERM and TXC to us |
| 45 | {ok, Lsc} = gen_fsm:start_link(mtp2_lsc, [self(), self(), self(),self()], [{debug, [trace]}]), |
| 46 | {ok, Iac} = gen_fsm:sync_send_event(Lsc, get_iac_pid), |
| 47 | gen_fsm:send_event(Lsc, power_on), |
| 48 | {ok, #m2pa_state{last_bsn_received=16#ffffff, last_fsn_sent=16#ffffff, |
| 49 | lsc_pid=Lsc, iac_pid=Iac}}. |
| 50 | |
| 51 | terminate(Reason, _State, _LoopDat) -> |
| 52 | io:format("Terminating ~p (Reason ~p)~n", [?MODULE, Reason]), |
| 53 | ok. |
| 54 | |
| 55 | code_change(_OldVsn, _State, LoopDat, _Extra) -> |
| 56 | {ok, LoopDat}. |
| 57 | |
| 58 | handle_event(_Event, State, LoopDat) -> |
| 59 | {next_state, State, LoopDat}. |
| 60 | |
| 61 | handle_info({lsc_txc, What}, State, LoopDat) when |
| 62 | What == start; What == retrieval_request_and_fsnc -> |
| 63 | {next_state, State, LoopDat}; |
| 64 | handle_info({Who, What}, established, LoopDat) when Who == iac_txc; Who == lsc_txc -> |
| 65 | Ls = iac_to_ls(What), |
| 66 | send_linkstate(Ls, LoopDat), |
| 67 | {next_state, established, LoopDat}; |
| 68 | handle_info(_Info, State, LoopDat) -> |
| 69 | {next_state, State, LoopDat}. |
| 70 | |
| 71 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
| 72 | % sctp_core callbacks |
| 73 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
| 74 | |
Harald Welte | 91b7965 | 2012-01-17 10:12:34 +0100 | [diff] [blame^] | 75 | prim_up(Prim, State, LoopDat) -> |
| 76 | % default: forward all primitives to the user |
| 77 | {ok, Prim, LoopDat}. |
| 78 | |
| 79 | |
Harald Welte | 26bdef2 | 2012-01-16 22:22:17 +0100 | [diff] [blame] | 80 | % sctp_core indicates that ew have received some data... |
| 81 | rx_sctp(#sctp_sndrcvinfo{ppid = ?M2PA_PPID}, Data, State, LoopDat) -> |
| 82 | {ok, M2pa} = m2pa_codec:parse_msg(Data), |
| 83 | FsnRecv = M2pa#m2pa_msg.fwd_seq_nr, |
| 84 | % FIXME: check sequenc number linearity |
| 85 | case M2pa of |
| 86 | #m2pa_msg{msg_class = ?M2PA_CLASS_M2PA, |
| 87 | msg_type = ?M2PA_TYPE_USER} -> |
| 88 | Mtp3 = M2pa#m2pa_msg.mtp3, |
| 89 | Prim = osmo_util:make_prim('MTP','TRANSFER',indication, Mtp3), |
| 90 | {ok, Prim, LoopDat#m2pa_state{last_bsn_received = FsnRecv}}; |
| 91 | #m2pa_msg{msg_type = ?M2PA_TYPE_LINK} -> |
| 92 | handle_linkstate(M2pa, LoopDat), |
| 93 | {ignore, LoopDat}; |
| 94 | _ -> |
| 95 | % do something with link related msgs |
| 96 | io:format("M2PA Unknown message ~p in state ~p~n", [M2pa, State]), |
| 97 | {ignore, State, LoopDat} |
| 98 | end. |
| 99 | |
| 100 | % MTP-TRANSFER.req has arrived at sctp_core, encapsulate+tx it |
| 101 | mtp_xfer(Mtp3, LoopDat) -> |
| 102 | Fsn = inc_seq_nr(LoopDat#m2pa_state.last_fsn_sent), |
| 103 | M2pa = #m2pa_msg{msg_class = ?M2PA_CLASS_M2PA, |
| 104 | msg_type = ?M2PA_TYPE_USER, |
| 105 | fwd_seq_nr = Fsn, |
| 106 | back_seq_nr = LoopDat#m2pa_state.last_bsn_received, |
| 107 | mtp3 = Mtp3}, |
| 108 | M2paBin = m2pa_codec:encode_msg(M2pa), |
| 109 | LoopDat2 = LoopDat#m2pa_state{last_fsn_sent = Fsn}, |
| 110 | tx_sctp(?M2PA_STREAM_USER, M2paBin), |
| 111 | LoopDat2. |
| 112 | |
| 113 | state_change(_, established, LoopDat) -> |
| 114 | % emulate a 'start' from LSC |
| 115 | gen_fsm:send_event(LoopDat#m2pa_state.lsc_pid, start), |
| 116 | LoopDat; |
| 117 | state_change(established, _, LoopDat) -> |
| 118 | gen_fsm:send_event(LoopDat#m2pa_state.lsc_pid, link_failure), |
| 119 | LoopDat; |
| 120 | state_change(_, _, LoopDat) -> |
| 121 | LoopDat. |
| 122 | |
| 123 | |
| 124 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
| 125 | % helper functions |
| 126 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
| 127 | |
| 128 | inc_seq_nr(SeqNr) when is_integer(SeqNr) -> |
| 129 | SeqNr + 1 rem 16#FFFFFF. |
| 130 | |
| 131 | handle_linkstate(M2pa, LoopDat) when is_record(M2pa, m2pa_msg) -> |
| 132 | Linkstate = proplists:get_value(link_state, M2pa#m2pa_msg.parameters), |
| 133 | LsMtp2 = ls_to_iac(Linkstate), |
| 134 | if LsMtp2 == fisu -> |
| 135 | gen_fsm:send_event(LoopDat#m2pa_state.lsc_pid, fisu_msu_received); |
| 136 | LsMtp2 == si_po -> |
| 137 | gen_fsm:send_event(LoopDat#m2pa_state.lsc_pid, LsMtp2); |
| 138 | LsMtp2 == si_n; LsMtp2 == si_e; LsMtp2 == si_o; LsMtp2 == si_os -> |
| 139 | gen_fsm:send_event(LoopDat#m2pa_state.lsc_pid, LsMtp2), |
| 140 | gen_fsm:send_event(LoopDat#m2pa_state.iac_pid, LsMtp2) |
| 141 | end. |
| 142 | |
| 143 | % convert M2PA link state to MTP2 |
| 144 | ls_to_iac(?M2PA_LS_OOS) -> |
| 145 | si_os; |
| 146 | ls_to_iac(?M2PA_LS_ALIGNMENT) -> |
| 147 | si_o; |
| 148 | ls_to_iac(?M2PA_LS_PROVING_NORMAL) -> |
| 149 | si_n; |
| 150 | ls_to_iac(?M2PA_LS_PROVING_EMERG) -> |
| 151 | si_e; |
| 152 | ls_to_iac(?M2PA_LS_READY) -> |
| 153 | fisu; |
| 154 | ls_to_iac(?M2PA_LS_PROC_OUTAGE) -> |
| 155 | si_po; |
| 156 | ls_to_iac(?M2PA_LS_PROC_RECOVERED) -> |
| 157 | fisu; |
| 158 | ls_to_iac(?M2PA_LS_BUSY) -> |
| 159 | si_b. |
| 160 | % FIXME: what about BUSY_ENDED? |
| 161 | |
| 162 | |
| 163 | % convert MTP2 link state to M2PA |
| 164 | iac_to_ls(si_os) -> |
| 165 | ?M2PA_LS_OOS; |
| 166 | iac_to_ls(si_o) -> |
| 167 | ?M2PA_LS_ALIGNMENT; |
| 168 | iac_to_ls(si_n) -> |
| 169 | ?M2PA_LS_PROVING_NORMAL; |
| 170 | iac_to_ls(si_e) -> |
| 171 | ?M2PA_LS_PROVING_EMERG; |
| 172 | iac_to_ls(fisu) -> |
| 173 | ?M2PA_LS_READY; |
| 174 | iac_to_ls(msu) -> |
| 175 | ?M2PA_LS_READY; |
| 176 | iac_to_ls(si_po) -> |
| 177 | ?M2PA_LS_PROC_OUTAGE; |
| 178 | iac_to_ls(si_b) -> |
| 179 | ?M2PA_LS_BUSY. |
| 180 | |
| 181 | % Chapter 4.1.2 of RFC4165 |
| 182 | ls_stream(?M2PA_LS_PROC_OUTAGE) -> |
| 183 | 1; |
| 184 | ls_stream(?M2PA_LS_PROC_RECOVERED) -> |
| 185 | 1; |
| 186 | ls_stream(Foo) when is_integer(Foo) -> |
| 187 | 0. |
| 188 | |
| 189 | send_linkstate(Ls, LoopDat) when is_integer(Ls) -> |
| 190 | Stream = ls_stream(Ls), |
| 191 | M2pa = #m2pa_msg{msg_class = ?M2PA_CLASS_M2PA, |
| 192 | msg_type = ?M2PA_TYPE_LINK, |
| 193 | fwd_seq_nr = LoopDat#m2pa_state.last_fsn_sent, |
| 194 | back_seq_nr = LoopDat#m2pa_state.last_bsn_received, |
| 195 | parameters = [{link_state, Ls}]}, |
| 196 | M2paBin = m2pa_codec:encode_msg(M2pa), |
| 197 | tx_sctp(Stream, M2paBin), |
| 198 | LoopDat. |
| 199 | |
| 200 | tx_sctp(Stream, Payload) when is_integer(Stream), is_binary(Payload) -> |
| 201 | Param = {Stream, ?M2PA_PPID, Payload}, |
| 202 | % sent to 'ourselves' (behaviour master module) |
| 203 | gen_fsm:send_event(self(), osmo_util:make_prim('SCTP','TRANSFER',request,Param)). |