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xmpp.chapril.org-ejabberd/src/ejabberd_global_router.erl

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%%%----------------------------------------------------------------------
%%% File : ejabberd_global_router.erl
%%% Author : Geoff Cant <gcant@process-one.net>
%%% Purpose : Router for virtual global routes
%%% Created : 07 Aug 2002 by Geoff Cant <gcant@process-one.net>
%%%
%%%
%%% ejabberd, Copyright (C) 2002-2012 ProcessOne
%%%
%%% This program is free software; you can redistribute it and/or
%%% modify it under the terms of the GNU General Public License as
%%% published by the Free Software Foundation; either version 2 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 General Public License
%%% along with this program; if not, write to the Free Software
%%% Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
%%% 02111-1307 USA
%%%
%%%----------------------------------------------------------------------
-module(ejabberd_global_router).
-behaviour(gen_server).
-include("ejabberd.hrl").
-include("ejabberd_global_router.hrl").
%% API
-export([start_link/0
,route/3
,route/4
,find_route/1
,register_route/1
,register_route/2
,unregister_route/1
,unregister_route/2
,expand_routes/1
,all_prefixes/0
,server_host/2
]).
%% Eunit test exports.
-export([remove_prefix/2
,find_prefix/2
]).
%% gen_server callbacks
-export([init/1, handle_call/3, handle_cast/2, handle_info/2,
terminate/2, code_change/3]).
-record(state, {}).
%%====================================================================
%% API
%%====================================================================
%%--------------------------------------------------------------------
%% @spec start_link() -> {ok,Pid} | ignore | {error,Error}
%% @doc Starts the server
%% @end
%%--------------------------------------------------------------------
start_link() ->
gen_server:start_link({local, ?MODULE}, ?MODULE, [], []).
route(From, To, Packet) ->
case find_route(To) of
Route = #global_route{} ->
route(Route, From, To, Packet);
no_route ->
ok
end.
route(#global_route{pids=Pids}, From, To, Packet) ->
Pid = pick_route(Pids),
Pid ! {route, From, To, Packet},
ok.
find_route(Domain) ->
case prefix_match(Domain, all_prefixes()) of
nomatch ->
no_route;
Prefix when is_list(Prefix) ->
dirty_get_route(Prefix)
end.
register_route(Prefix) ->
register_route(Prefix, self()).
register_route(Prefix, Pid) ->
Route = #global_route{prefix=Prefix,
pids=[Pid]},
{atomic, ok} = mnesia:transaction(fun write_route/1,
[Route]),
ok.
unregister_route(Prefix) ->
unregister_route(Prefix, self()).
unregister_route(Prefix, Pid) ->
mnesia:transaction(fun delete_route/2, [Prefix, Pid]).
expand_routes(Domain) ->
[expand_route(Prefix, Domain) || Prefix <- all_prefixes()].
expand_route(Prefix, Domain) ->
lists:append([Prefix, ".", Domain]).
all_prefixes() ->
mnesia:dirty_all_keys(global_route).
server_host(Host, Pid) ->
#global_route{prefix=P,pids=Pids} = find_route(Host),
true = lists:member(Pid, Pids),
remove_prefix(P, Host).
%%====================================================================
%% gen_server callbacks
%%====================================================================
%%--------------------------------------------------------------------
%% @private
%% @spec init(Args) -> {ok, State} |
%% {ok, State, Timeout} |
%% ignore |
%% {stop, Reason}
%% @doc Initialises the server's state
%% @end
%%--------------------------------------------------------------------
init([]) ->
update_tables(),
mnesia:create_table(global_route,
[{ram_copies, [node()]},
{type, set},
{attributes,
record_info(fields, global_route)}]),
mnesia:add_table_copy(global_route, node(), ram_copies),
{ok, #state{}}.
%%--------------------------------------------------------------------
%% @private
%% @spec
%% handle_call(Request, From, State) -> {reply, Reply, State} |
%% {reply, Reply, State, Timeout} |
%% {noreply, State} |
%% {noreply, State, Timeout} |
%% {stop, Reason, Reply, State} |
%% {stop, Reason, State}
%% @doc Call message handler callbacks
%% @end
%%--------------------------------------------------------------------
handle_call(Call, _From, State) ->
?WARNING_MSG("Unexpected call ~p.", [Call]),
{noreply, State}.
%%--------------------------------------------------------------------
%% @private
%% @spec
%% handle_cast(Msg, State) -> {noreply, State} |
%% {noreply, State, Timeout} |
%% {stop, Reason, State}
%% @doc Cast message handler callbacks
%% @end
%%--------------------------------------------------------------------
handle_cast(Msg, State) ->
?WARNING_MSG("Unexpected cast ~p", [Msg]),
{noreply, State}.
%%--------------------------------------------------------------------
%% @private
%% @spec
%% handle_info(Info, State) -> {noreply, State} |
%% {noreply, State, Timeout} |
%% {stop, Reason, State}
%% @doc Non gen-server message handler callbacks
%% @end
%%--------------------------------------------------------------------
handle_info(Info, State) ->
?WARNING_MSG("Unexpected info ~p", [Info]),
{noreply, State}.
%%--------------------------------------------------------------------
%% @private
%% @spec terminate(Reason, State) -> void()
%% @doc This function is called by a gen_server when it is about to
%% terminate. It should be the opposite of Module:init/1 and do any necessary
%% cleaning up. When it returns, the gen_server terminates with Reason.
%% The return value is ignored.
%% @end
%%--------------------------------------------------------------------
terminate(_Reason, _State) ->
ok.
%%--------------------------------------------------------------------
%% @private
%% @spec code_change(OldVsn, State, Extra) -> {ok, NewState}
%% @doc Convert process state when code is changed
%% @end
%%--------------------------------------------------------------------
code_change(_OldVsn, State, _Extra) ->
{ok, State}.
pick_route(Pids) when is_list(Pids) ->
pick_local_route(Pids).
pick_local_route(Pids) when is_list(Pids) ->
case [Pid || Pid <- Pids,
node(Pid) =:= node()] of
[] -> pick_remote_route(Pids);
LocalPids -> pick_one_route(LocalPids)
end.
pick_remote_route(Pids) when is_list(Pids) -> pick_one_route(Pids).
pick_one_route(Pids) when is_list(Pids) ->
hd(Pids). % should pick random pid?
update_tables() ->
CorrectAttributes = record_info(fields, global_route),
case catch mnesia:table_info(global_route, attributes) of
CorrectAttributes ->
ok;
IncorrectAttributes when is_list(IncorrectAttributes) ->
mnesia:delete_table(global_route);
{'EXIT', _} ->
ok
end.
write_route(R = #global_route{prefix=Prefix}) ->
NewRoute = case mnesia:read({global_route, Prefix}) of
[] -> R;
[OldRoute] ->
combine_routes(OldRoute, R)
end,
ok = mnesia:write(NewRoute).
delete_route(Prefix, Pid) ->
case mnesia:read({global_route, Prefix}, write) of
[] -> ok;
[#global_route{pids=[Pid]}] ->
mnesia:delete({global_route, Prefix});
[Route = #global_route{pids=Pids}] ->
mnesia:write(Route#global_route{pids=Pids -- [Pid]})
end.
combine_routes(R = #global_route{prefix=P, pids=APids},
#global_route{prefix=P, pids=BPids}) ->
R#global_route{pids=lists:usort(APids ++ BPids)}.
prefix_match(Domain, Prefixes) ->
case find_prefix(Domain, Prefixes) of
[] -> nomatch;
[Prefix] -> Prefix;
_Prefixes ->
erlang:error(multiple_prefix_matches)
end.
dirty_get_route(Prefix) ->
case mnesia:dirty_read({global_route, Prefix}) of
[Route = #global_route{}] ->
Route;
_ -> no_route
end.
find_prefix(Domain, PossiblePrefixes) ->
[Prefix
|| Prefix <- PossiblePrefixes,
lists:prefix(Prefix, Domain)].
remove_prefix(Prefix, Domain) ->
[$. | BareDomain] = Domain -- Prefix,
BareDomain.
%%--------------------------------------------------------------------
%%% Eunit Tests.
%%--------------------------------------------------------------------
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