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% SCCP user interface procedures
% (C) 2011 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(sccp_user).
-behaviour(gen_server).
%-include_lib("osmo_ss7/osmo_util.hrl").
%-include_lib("osmo_ss7/sccp.hrl").
%-include_lib("osmo_ss7/mtp3.hrl").
% gen_fsm callbacks
-export([init/1, handle_call/3, handle_cast/2, handle_info/2,
terminate/2, code_change/3]).
% our published API
-export([start_link/0]).
% client functions, may internally talk to our sccp_user server
-export([bind_ssn/2, unbind_ssn/2, pid_for_ssn/2, local_ssn_avail/2]).
-record(scu_state, {
user_table
}).
-record(scu_record, {
ssn_pc,
user_pid
}).
% initialization code
start_link() ->
gen_server:start_link({local, ?MODULE}, ?MODULE, [], []).
init(_Arg) ->
UserTbl = ets:new(sccp_user_tbl, [ordered_set, named_table,
{keypos, #scu_record.ssn_pc}]),
{ok, #scu_state{user_table = UserTbl}}.
% client side code
bind_ssn(Ssn, Pc) ->
gen_server:call(?MODULE, {bind_ssn, Ssn, Pc}).
unbind_ssn(Ssn, Pc) ->
gen_server:call(?MODULE, {unbind_ssn, Ssn, Pc}).
% determine the pid registered for a given {Ssn, PC}
pid_for_ssn(Ssn, Pc) ->
% as this is only a read access, we read the ets table directly
% rather than going through call/2
case ets:lookup(sccp_user_tbl, {Ssn, Pc}) of
[#scu_record{user_pid = UserPid}] ->
{ok, UserPid};
_ ->
{error, no_such_ssn}
end.
local_ssn_avail(Ssn, Pc) ->
case pid_for_ssn(Ssn, Pc) of
{ok, UserPid} ->
true;
_ ->
false
end.
% server side code
% bind a {SSN, PC} tuple to the pid of the caller
handle_call({bind_ssn, Ssn, Pc}, {FromPid, _FromRef}, S) ->
#scu_state{user_table = Tbl} = S,
NewRec = #scu_record{ssn_pc= {Ssn, Pc}, user_pid = FromPid},
case ets:insert_new(Tbl, NewRec) of
false ->
{reply, {error, ets_insert}, S};
Error ->
% We need to trap the user Pid for EXIT
% in order to automatically remove any SSN if
% the user process dies
link(FromPid),
{reply, ok, S}
end;
% unbind a {SSN, PC} tuple from the pid of the caller
handle_call({unbind_ssn, Ssn, Pc}, {FromPid, _FromRef}, S) ->
#scu_state{user_table = Tbl} = S,
DelRec = #scu_record{ssn_pc= {Ssn, Pc}, user_pid = FromPid},
ets:delete_object(Tbl, DelRec),
{reply, ok, S}.
handle_cast(Info, S) ->
error_logger:error_report(["unknown handle_cast",
{module, ?MODULE},
{info, Info}, {state, S}]),
{noreply, S}.
handle_info(Info, S) ->
error_logger:error_report(["unknown handle_info",
{module, ?MODULE},
{info, Info}, {state, S}]),
{noreply, S}.
terminate(Reason, _S) ->
io:format("terminating ~p with reason ~p", [?MODULE, Reason]),
ok.
code_change(_OldVsn, State, _Extra) ->
{ok, State}.
|
