path: root/src/ejabberd_service.erl

%%%----------------------------------------------------------------------
%%% File    : ejabberd_service.erl
%%% Author  : Alexey Shchepin <alexey@process-one.net>
%%% Purpose : External component management (XEP-0114)
%%% Created :  6 Dec 2002 by Alexey Shchepin <alexey@process-one.net>
%%%
%%%
%%% ejabberd, Copyright (C) 2002-2009   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_service).
-author('alexey@process-one.net').

-behaviour(gen_fsm).

%% External exports
-export([start/2,
	 start_link/2,
	 send_text/2,
	 send_element/2,
	 socket_type/0]).

%% gen_fsm callbacks
-export([init/1,
	 wait_for_stream/2,
	 wait_for_handshake/2,
	 stream_established/2,
	 handle_event/3,
	 handle_sync_event/4,
	 code_change/4,
	 handle_info/3,
	 terminate/3]).

-include("ejabberd.hrl").
-include("jlib.hrl").

-record(state, {socket, sockmod, streamid,
		hosts, password, access,
		check_from}).

%-define(DBGFSM, true).

-ifdef(DBGFSM).
-define(FSMOPTS, [{debug, [trace]}]).
-else.
-define(FSMOPTS, []).
-endif.

-define(STREAM_HEADER,
	"<?xml version='1.0'?>"
	"<stream:stream "
	"xmlns:stream='http://etherx.jabber.org/streams' "
	"xmlns='jabber:component:accept' "
	"id='~s' from='~s'>"
       ).

-define(STREAM_TRAILER, "</stream:stream>").

-define(INVALID_HEADER_ERR,
	"<stream:stream "
	"xmlns:stream='http://etherx.jabber.org/streams'>"
	"<stream:error>Invalid Stream Header</stream:error>"
	"</stream:stream>"
       ).

-define(INVALID_HANDSHAKE_ERR,
	"<stream:error>Invalid Handshake</stream:error>"
	"</stream:stream>"
       ).

-define(INVALID_XML_ERR,
	xml:element_to_string(?SERR_XML_NOT_WELL_FORMED)).
-define(INVALID_NS_ERR,
	xml:element_to_string(?SERR_INVALID_NAMESPACE)).

%%%----------------------------------------------------------------------
%%% API
%%%----------------------------------------------------------------------
start(SockData, Opts) ->
    supervisor:start_child(ejabberd_service_sup, [SockData, Opts]).

start_link(SockData, Opts) ->
    gen_fsm:start_link(ejabberd_service, [SockData, Opts], ?FSMOPTS).

socket_type() ->
    xml_stream.

%%%----------------------------------------------------------------------
%%% Callback functions from gen_fsm
%%%----------------------------------------------------------------------

%%----------------------------------------------------------------------
%% Func: init/1
%% Returns: {ok, StateName, StateData}          |
%%          {ok, StateName, StateData, Timeout} |
%%          ignore                              |
%%          {stop, StopReason}
%%----------------------------------------------------------------------
init([{SockMod, Socket}, Opts]) ->
    ?INFO_MSG("(~w) External service connected", [Socket]),
    Access = case lists:keysearch(access, 1, Opts) of
		 {value, {_, A}} -> A;
		 _ -> all
	     end,
    {Hosts, Password} =
	case lists:keysearch(hosts, 1, Opts) of
	    {value, {_, Hs, HOpts}} ->
		case lists:keysearch(password, 1, HOpts) of
		    {value, {_, P}} ->
			{Hs, P};
		    _ ->
			% TODO: generate error
			false
		end;
	    _ ->
		case lists:keysearch(host, 1, Opts) of
		    {value, {_, H, HOpts}} ->
			case lists:keysearch(password, 1, HOpts) of
			    {value, {_, P}} ->
				{[H], P};
			    _ ->
				% TODO: generate error
				false
			end;
		    _ ->
			% TODO: generate error
			false
		end
	end,
    Shaper = case lists:keysearch(shaper_rule, 1, Opts) of
		 {value, {_, S}} -> S;
		 _ -> none
	     end,
    CheckFrom = case lists:keysearch(service_check_from, 1, Opts) of
		 {value, {_, CF}} -> CF;
		 _ -> true
	     end,
    SockMod:change_shaper(Socket, Shaper),
    {ok, wait_for_stream, #state{socket = Socket,
				 sockmod = SockMod,
				 streamid = new_id(),
				 hosts = Hosts,
				 password = Password,
				 access = Access,
				 check_from = CheckFrom
				 }}.

%%----------------------------------------------------------------------
%% Func: StateName/2
%% Returns: {next_state, NextStateName, NextStateData}          |
%%          {next_state, NextStateName, NextStateData, Timeout} |
%%          {stop, Reason, NewStateData}
%%----------------------------------------------------------------------

wait_for_stream({xmlstreamstart, _Name, Attrs}, StateData) ->
    case xml:get_attr_s("xmlns", Attrs) of
	"jabber:component:accept" ->
	    %% Note: XEP-0114 requires to check that destination is a Jabber
	    %% component served by this Jabber server.
	    %% However several transports don't respect that,
	    %% so ejabberd doesn't check 'to' attribute (EJAB-717)
	    To = xml:get_attr_s("to", Attrs),
	    Header = io_lib:format(?STREAM_HEADER,
				   [StateData#state.streamid, xml:crypt(To)]),
	    send_text(StateData, Header),
	    {next_state, wait_for_handshake, StateData};
	_ ->
	    send_text(StateData, ?INVALID_HEADER_ERR),
	    {stop, normal, StateData}
    end;

wait_for_stream({xmlstreamerror, _}, StateData) ->
    Header = io_lib:format(?STREAM_HEADER,
			   ["none", ?MYNAME]),
    send_text(StateData,
	      Header ++ ?INVALID_XML_ERR ++ ?STREAM_TRAILER),
    {stop, normal, StateData};

wait_for_stream(closed, StateData) ->
    {stop, normal, StateData}.


wait_for_handshake({xmlstreamelement, El}, StateData) ->
    {xmlelement, Name, _Attrs, Els} = El,
    case {Name, xml:get_cdata(Els)} of
	{"handshake", Digest} ->
	    case sha:sha(StateData#state.streamid ++
			 StateData#state.password) of
		Digest ->
		    send_text(StateData, "<handshake/>"),
		    lists:foreach(
		      fun(H) ->
			      ejabberd_router:register_route(H),
			      ?INFO_MSG("Route registered for service ~p~n", [H])
		      end, StateData#state.hosts),
		    {next_state, stream_established, StateData};
		_ ->
		    send_text(StateData, ?INVALID_HANDSHAKE_ERR),
		    {stop, normal, StateData}
	    end;
	_ ->
	    {next_state, wait_for_handshake, StateData}
    end;

wait_for_handshake({xmlstreamend, _Name}, StateData) ->
    {stop, normal, StateData};

wait_for_handshake({xmlstreamerror, _}, StateData) ->
    send_text(StateData, ?INVALID_XML_ERR ++ ?STREAM_TRAILER),
    {stop, normal, StateData};

wait_for_handshake(closed, StateData) ->
    {stop, normal, StateData}.


stream_established({xmlstreamelement, El}, StateData) ->
    NewEl = jlib:remove_attr("xmlns", El),
    {xmlelement, Name, Attrs, _Els} = NewEl,
    From = xml:get_attr_s("from", Attrs),
    FromJID = case StateData#state.check_from of
		  %% If the admin does not want to check the from field
		  %% when accept packets from any address.
		  %% In this case, the component can send packet of
		  %% behalf of the server users.
		  false -> jlib:string_to_jid(From);
		  %% The default is the standard behaviour in XEP-0114
		  _ ->
		      FromJID1 = jlib:string_to_jid(From),
		      case FromJID1 of
			  #jid{lserver = Server} ->
			      case lists:member(Server, StateData#state.hosts) of
				  true -> FromJID1;
				  false -> error
			      end;
			  _ -> error
		      end
	      end,
    To = xml:get_attr_s("to", Attrs),
    ToJID = case To of
		"" -> error;
		_ -> jlib:string_to_jid(To)
	    end,
    if ((Name == "iq") or
	(Name == "message") or
	(Name == "presence")) and
       (ToJID /= error) and (FromJID /= error) ->
	    ejabberd_router:route(FromJID, ToJID, NewEl);
       true ->
	    Err = jlib:make_error_reply(NewEl, ?ERR_BAD_REQUEST),
	    send_element(StateData, Err),
	    error
    end,
    {next_state, stream_established, StateData};

stream_established({xmlstreamend, _Name}, StateData) ->
    % TODO
    {stop, normal, StateData};

stream_established({xmlstreamerror, _}, StateData) ->
    send_text(StateData, ?INVALID_XML_ERR ++ ?STREAM_TRAILER),
    {stop, normal, StateData};

stream_established(closed, StateData) ->
    % TODO
    {stop, normal, StateData}.



%%----------------------------------------------------------------------
%% Func: StateName/3
%% Returns: {next_state, NextStateName, NextStateData}            |
%%          {next_state, NextStateName, NextStateData, Timeout}   |
%%          {reply, Reply, NextStateName, NextStateData}          |
%%          {reply, Reply, NextStateName, NextStateData, Timeout} |
%%          {stop, Reason, NewStateData}                          |
%%          {stop, Reason, Reply, NewStateData}
%%----------------------------------------------------------------------
%state_name(Event, From, StateData) ->
%    Reply = ok,
%    {reply, Reply, state_name, StateData}.

%%----------------------------------------------------------------------
%% Func: handle_event/3
%% Returns: {next_state, NextStateName, NextStateData}          |
%%          {next_state, NextStateName, NextStateData, Timeout} |
%%          {stop, Reason, NewStateData}
%%----------------------------------------------------------------------
handle_event(_Event, StateName, StateData) ->
    {next_state, StateName, StateData}.

%%----------------------------------------------------------------------
%% Func: handle_sync_event/4
%% Returns: {next_state, NextStateName, NextStateData}            |
%%          {next_state, NextStateName, NextStateData, Timeout}   |
%%          {reply, Reply, NextStateName, NextStateData}          |
%%          {reply, Reply, NextStateName, NextStateData, Timeout} |
%%          {stop, Reason, NewStateData}                          |
%%          {stop, Reason, Reply, NewStateData}
%%----------------------------------------------------------------------
handle_sync_event(_Event, _From, StateName, StateData) ->
    Reply = ok,
    {reply, Reply, StateName, StateData}.

code_change(_OldVsn, StateName, StateData, _Extra) ->
    {ok, StateName, StateData}.

%%----------------------------------------------------------------------
%% Func: handle_info/3
%% Returns: {next_state, NextStateName, NextStateData}          |
%%          {next_state, NextStateName, NextStateData, Timeout} |
%%          {stop, Reason, NewStateData}
%%----------------------------------------------------------------------
handle_info({send_text, Text}, StateName, StateData) ->
    send_text(StateData, Text),
    {next_state, StateName, StateData};
handle_info({send_element, El}, StateName, StateData) ->
    send_element(StateData, El),
    {next_state, StateName, StateData};
handle_info({route, From, To, Packet}, StateName, StateData) ->
    case acl:match_rule(global, StateData#state.access, From) of
	allow ->
	    {xmlelement, Name, Attrs, Els} = Packet,
	    Attrs2 = jlib:replace_from_to_attrs(jlib:jid_to_string(From),
						jlib:jid_to_string(To),
						Attrs),
	    Text = xml:element_to_string({xmlelement, Name, Attrs2, Els}),
	    send_text(StateData, Text);
	deny ->
	    Err = jlib:make_error_reply(Packet, ?ERR_NOT_ALLOWED),
	    ejabberd_router:route(To, From, Err)
    end,
    {next_state, StateName, StateData}.


%%----------------------------------------------------------------------
%% Func: terminate/3
%% Purpose: Shutdown the fsm
%% Returns: any
%%----------------------------------------------------------------------
terminate(Reason, StateName, StateData) ->
    ?INFO_MSG("terminated: ~p", [Reason]),
    case StateName of
	stream_established ->
	    lists:foreach(
	      fun(H) ->
		      ejabberd_router:unregister_route(H)
	      end, StateData#state.hosts);
	_ ->
	    ok
    end,
    (StateData#state.sockmod):close(StateData#state.socket),
    ok.

%%%----------------------------------------------------------------------
%%% Internal functions
%%%----------------------------------------------------------------------

send_text(StateData, Text) ->
    (StateData#state.sockmod):send(StateData#state.socket, Text).

send_element(StateData, El) ->
    send_text(StateData, xml:element_to_string(El)).

new_id() ->
    randoms:get_string().