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%%%-------------------------------------------------------------------
%%% @doc Implements support for XEP-0199 (XMPP Ping) and periodic
%%% keepalives.
%%%
%%% <p>When enabled (see below), ejabberd will respond correctly to
%%% ping packets, as defined in XEP-0199.</p>
%%%
%%% <p>In addition you can have the server generate pings to clients
%%% as a method of keeping them alive or checking
%%% availibility. However, this feature is disabled by default since
%%% it is mostly not needed and consumes resources. For "interesting"
%%% uses it can be enabled in the config (see below).</p>
%%%
%%% <p>To use this module simply include it in the modules section of
%%% your ejabberd config.</p>
%%%
%%% <p>Configuration options:</p>
%%% <dl>
%%% <dt>{send_pings, true | false}</dt>
%%% <dd>Whether to send pings to connected clients.</dd>
%%% <dt>{ping_interval, Seconds}</dt>
%%% <dd>How often to send pings to connected clients.</dd>
%%% </dl>
%%%
%%% @reference <a
%%% href="http://xmpp.org/extensions/xep-0199.html">XEP-0199</a>
%%% @end
%%% -------------------------------------------------------------------
-module(mod_ping).
-author('bjc@kublai.com').
-behavior(gen_mod).
-behavior(gen_server).
-include("ejabberd.hrl").
-include("jlib.hrl").
-define(SUPERVISOR, ejabberd_sup).
-define(NS_PING, "urn:xmpp:ping").
-define(DEFAULT_SEND_PINGS, false). % bool()
-define(DEFAULT_PING_INTERVAL, 60). % seconds
-define(DICT, dict).
%% API
-export([start_link/2, start_ping/2, stop_ping/2]).
%% gen_mod callbacks
-export([start/2, stop/1]).
%% gen_server callbacks
-export([init/1, terminate/2, handle_call/3, handle_cast/2,
handle_info/2, code_change/3]).
%% Hook callbacks
-export([iq_ping/3, user_online/3, user_offline/3, user_send/3]).
-record(state, {host = "",
send_pings = ?DEFAULT_SEND_PINGS,
ping_interval = ?DEFAULT_PING_INTERVAL,
timers = ?DICT:new()}).
%%====================================================================
%% API
%%====================================================================
start_link(Host, Opts) ->
Proc = gen_mod:get_module_proc(Host, ?MODULE),
gen_server:start_link({local, Proc}, ?MODULE, [Host, Opts], []).
start_ping(Host, JID) ->
Proc = gen_mod:get_module_proc(Host, ?MODULE),
gen_server:cast(Proc, {start_ping, JID}).
stop_ping(Host, JID) ->
Proc = gen_mod:get_module_proc(Host, ?MODULE),
gen_server:cast(Proc, {stop_ping, JID}).
%%====================================================================
%% gen_mod callbacks
%%====================================================================
start(Host, Opts) ->
Proc = gen_mod:get_module_proc(Host, ?MODULE),
PingSpec = {Proc, {?MODULE, start_link, [Host, Opts]},
transient, 2000, worker, [?MODULE]},
supervisor:start_child(?SUPERVISOR, PingSpec).
stop(Host) ->
Proc = gen_mod:get_module_proc(Host, ?MODULE),
gen_server:call(Proc, stop),
supervisor:delete_child(?SUPERVISOR, Proc).
%%====================================================================
%% gen_server callbacks
%%====================================================================
init([Host, Opts]) ->
SendPings = gen_mod:get_opt(send_pings, Opts, ?DEFAULT_SEND_PINGS),
PingInterval = gen_mod:get_opt(ping_interval, Opts, ?DEFAULT_PING_INTERVAL),
IQDisc = gen_mod:get_opt(iqdisc, Opts, one_queue),
mod_disco:register_feature(Host, ?NS_PING),
gen_iq_handler:add_iq_handler(ejabberd_sm, Host, ?NS_PING,
?MODULE, iq_ping, IQDisc),
gen_iq_handler:add_iq_handler(ejabberd_local, Host, ?NS_PING,
?MODULE, iq_ping, IQDisc),
case SendPings of
true ->
ejabberd_hooks:add(sm_register_connection_hook, Host,
?MODULE, user_online, 100),
ejabberd_hooks:add(sm_remove_connection_hook, Host,
?MODULE, user_offline, 100),
ejabberd_hooks:add(user_send_packet, Host,
?MODULE, user_send, 100);
_ ->
ok
end,
{ok, #state{host = Host,
send_pings = SendPings,
ping_interval = PingInterval,
timers = ?DICT:new()}}.
terminate(_Reason, #state{host = Host}) ->
ejabberd_hooks:delete(sm_remove_connection_hook, Host,
?MODULE, user_offline, 100),
ejabberd_hooks:delete(sm_register_connection_hook, Host,
?MODULE, user_online, 100),
ejabberd_hooks:delete(user_send_packet, Host,
?MODULE, user_send, 100),
gen_iq_handler:remove_iq_handler(ejabberd_local, Host, ?NS_PING),
gen_iq_handler:remove_iq_handler(ejabberd_sm, Host, ?NS_PING),
mod_disco:unregister_feature(Host, ?NS_PING).
handle_call(stop, _From, State) ->
{stop, normal, ok, State};
handle_call(_Req, _From, State) ->
{reply, {error, badarg}, State}.
handle_cast({start_ping, JID}, State) ->
Timers = add_timer(JID, State#state.ping_interval, State#state.timers),
{noreply, State#state{timers = Timers}};
handle_cast({stop_ping, JID}, State) ->
Timers = del_timer(JID, State#state.timers),
{noreply, State#state{timers = Timers}};
handle_cast({iq_pong, JID, timeout}, State) ->
Timers = del_timer(JID, State#state.timers),
ejabberd_hooks:run(user_ping_timeout, State#state.host, [JID]),
{noreply, State#state{timers = Timers}};
handle_cast(_Msg, State) ->
{noreply, State}.
handle_info({timeout, _TRef, {ping, JID}}, State) ->
IQ = #iq{type = get,
sub_el = [{xmlelement, "ping", [{"xmlns", ?NS_PING}], []}]},
Pid = self(),
F = fun(Response) ->
gen_server:cast(Pid, {iq_pong, JID, Response})
end,
From = jlib:make_jid("", State#state.host, ""),
ejabberd_local:route_iq(From, JID, IQ, F),
Timers = add_timer(JID, State#state.ping_interval, State#state.timers),
{noreply, State#state{timers = Timers}};
handle_info(_Info, State) ->
{noreply, State}.
code_change(_OldVsn, State, _Extra) ->
{ok, State}.
%%====================================================================
%% Hook callbacks
%%====================================================================
iq_ping(_From, _To, #iq{type = Type, sub_el = SubEl} = IQ) ->
case {Type, SubEl} of
{get, {xmlelement, "ping", _, _}} ->
IQ#iq{type = result, sub_el = []};
_ ->
IQ#iq{type = error, sub_el = [SubEl, ?ERR_FEATURE_NOT_IMPLEMENTED]}
end.
user_online(_SID, JID, _Info) ->
start_ping(JID#jid.lserver, JID).
user_offline(_SID, JID, _Info) ->
stop_ping(JID#jid.lserver, JID).
user_send(JID, _From, _Packet) ->
start_ping(JID#jid.lserver, JID).
%%====================================================================
%% Internal functions
%%====================================================================
add_timer(JID, Interval, Timers) ->
LJID = jlib:jid_tolower(JID),
NewTimers = case ?DICT:find(LJID, Timers) of
{ok, OldTRef} ->
cancel_timer(OldTRef),
?DICT:erase(LJID, Timers);
_ ->
Timers
end,
TRef = erlang:start_timer(Interval * 1000, self(), {ping, JID}),
?DICT:store(LJID, TRef, NewTimers).
del_timer(JID, Timers) ->
LJID = jlib:jid_tolower(JID),
case ?DICT:find(LJID, Timers) of
{ok, TRef} ->
cancel_timer(TRef),
?DICT:erase(LJID, Timers);
_ ->
Timers
end.
cancel_timer(TRef) ->
case erlang:cancel_timer(TRef) of
false ->
receive
{timeout, TRef, _} ->
ok
after 0 ->
ok
end;
_ ->
ok
end.
|
