1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
|
% 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/>.
-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)).
|
