%%%----------------------------------------------------------------------
%%% File : mod_carboncopy.erl
%%% Author : Eric Cestari <ecestari@process-one.net>
%%% Purpose : Message Carbons XEP-0280 0.8
%%% Created : 5 May 2008 by Mickael Remond <mremond@process-one.net>
%%% Usage : Add the following line in modules section of ejabberd.yml:
%%% {mod_carboncopy, []}
%%%
%%%
%%% ejabberd, Copyright (C) 2002-2022 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.,
%%% 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
%%%
%%%----------------------------------------------------------------------
-module (mod_carboncopy).
-author ('ecestari@process-one.net').
-protocol({xep, 280, '0.13.2'}).
-behaviour(gen_mod).
%% API:
-export([start/2, stop/1, reload/3]).
-export([user_send_packet/1, user_receive_packet/1,
iq_handler/1, disco_features/5,
depends/2, mod_options/1, mod_doc/0]).
-export([c2s_copy_session/2, c2s_session_opened/1, c2s_session_resumed/1]).
%% For debugging purposes
-export([list/2]).
-include("logger.hrl").
-include_lib("xmpp/include/xmpp.hrl").
-include("translate.hrl").
-type direction() :: sent | received.
-type c2s_state() :: ejabberd_c2s:state().
start(Host, _Opts) ->
ejabberd_hooks:add(disco_local_features, Host, ?MODULE, disco_features, 50),
%% why priority 89: to define clearly that we must run BEFORE mod_logdb hook (90)
ejabberd_hooks:add(user_send_packet,Host, ?MODULE, user_send_packet, 89),
ejabberd_hooks:add(user_receive_packet,Host, ?MODULE, user_receive_packet, 89),
ejabberd_hooks:add(c2s_copy_session, Host, ?MODULE, c2s_copy_session, 50),
ejabberd_hooks:add(c2s_session_resumed, Host, ?MODULE, c2s_session_resumed, 50),
ejabberd_hooks:add(c2s_session_opened, Host, ?MODULE, c2s_session_opened, 50),
gen_iq_handler:add_iq_handler(ejabberd_sm, Host, ?NS_CARBONS_2, ?MODULE, iq_handler).
stop(Host) ->
gen_iq_handler:remove_iq_handler(ejabberd_sm, Host, ?NS_CARBONS_2),
ejabberd_hooks:delete(disco_local_features, Host, ?MODULE, disco_features, 50),
%% why priority 89: to define clearly that we must run BEFORE mod_logdb hook (90)
ejabberd_hooks:delete(user_send_packet,Host, ?MODULE, user_send_packet, 89),
ejabberd_hooks:delete(user_receive_packet,Host, ?MODULE, user_receive_packet, 89),
ejabberd_hooks:delete(c2s_copy_session, Host, ?MODULE, c2s_copy_session, 50),
ejabberd_hooks:delete(c2s_session_resumed, Host, ?MODULE, c2s_session_resumed, 50),
ejabberd_hooks:delete(c2s_session_opened, Host, ?MODULE, c2s_session_opened, 50).
reload(_Host, _NewOpts, _OldOpts) ->
ok.
-spec disco_features({error, stanza_error()} | {result, [binary()]} | empty,
jid(), jid(), binary(), binary()) ->
{error, stanza_error()} | {result, [binary()]}.
disco_features(empty, From, To, <<"">>, Lang) ->
disco_features({result, []}, From, To, <<"">>, Lang);
disco_features({result, Feats}, _From, _To, <<"">>, _Lang) ->
{result, [?NS_CARBONS_2,?NS_CARBONS_RULES_0|Feats]};
disco_features(Acc, _From, _To, _Node, _Lang) ->
Acc.
-spec iq_handler(iq()) -> iq().
iq_handler(#iq{type = set, lang = Lang, from = From,
sub_els = [El]} = IQ) when is_record(El, carbons_enable);
is_record(El, carbons_disable) ->
{U, S, R} = jid:tolower(From),
Result = case El of
#carbons_enable{} -> enable(S, U, R, ?NS_CARBONS_2);
#carbons_disable{} -> disable(S, U, R)
end,
case Result of
ok ->
xmpp:make_iq_result(IQ);
{error, _} ->
Txt = ?T("Database failure"),
xmpp:make_error(IQ, xmpp:err_internal_server_error(Txt, Lang))
end;
iq_handler(#iq{type = set, lang = Lang} = IQ) ->
Txt = ?T("Only <enable/> or <disable/> tags are allowed"),
xmpp:make_error(IQ, xmpp:err_bad_request(Txt, Lang));
iq_handler(#iq{type = get, lang = Lang} = IQ)->
Txt = ?T("Value 'get' of 'type' attribute is not allowed"),
xmpp:make_error(IQ, xmpp:err_not_allowed(Txt, Lang)).
-spec user_send_packet({stanza(), ejabberd_c2s:state()})
-> {stanza(), ejabberd_c2s:state()} | {stop, {stanza(), ejabberd_c2s:state()}}.
user_send_packet({#message{meta = #{carbon_copy := true}}, _C2SState} = Acc) ->
%% Stop the hook chain, we don't want logging modules to duplicate this
%% message.
{stop, Acc};
user_send_packet({#message{from = From, to = To} = Msg, C2SState}) ->
{check_and_forward(From, To, Msg, sent), C2SState};
user_send_packet(Acc) ->
Acc.
-spec user_receive_packet({stanza(), ejabberd_c2s:state()})
-> {stanza(), ejabberd_c2s:state()} | {stop, {stanza(), ejabberd_c2s:state()}}.
user_receive_packet({#message{meta = #{carbon_copy := true}}, _C2SState} = Acc) ->
%% Stop the hook chain, we don't want logging modules to duplicate this
%% message.
{stop, Acc};
user_receive_packet({#message{to = To} = Msg, #{jid := JID} = C2SState}) ->
{check_and_forward(JID, To, Msg, received), C2SState};
user_receive_packet(Acc) ->
Acc.
-spec c2s_copy_session(c2s_state(), c2s_state()) -> c2s_state().
c2s_copy_session(State, #{user := U, server := S, resource := R}) ->
case ejabberd_sm:get_user_info(U, S, R) of
offline -> State;
Info ->
case lists:keyfind(carboncopy, 1, Info) of
{_, CC} -> State#{carboncopy => CC};
false -> State
end
end.
-spec c2s_session_resumed(c2s_state()) -> c2s_state().
c2s_session_resumed(#{user := U, server := S, resource := R,
carboncopy := CC} = State) ->
ejabberd_sm:set_user_info(U, S, R, carboncopy, CC),
maps:remove(carboncopy, State);
c2s_session_resumed(State) ->
State.
-spec c2s_session_opened(c2s_state()) -> c2s_state().
c2s_session_opened(State) ->
maps:remove(carboncopy, State).
% Modified from original version:
% - registered to the user_send_packet hook, to be called only once even for multicast
% - do not support "private" message mode, and do not modify the original packet in any way
% - we also replicate "read" notifications
-spec check_and_forward(jid(), jid(), message(), direction()) -> message().
check_and_forward(JID, To, Msg, Direction)->
case (is_chat_message(Msg) orelse
is_received_muc_invite(Msg, Direction)) andalso
not is_received_muc_pm(To, Msg, Direction) andalso
not xmpp:has_subtag(Msg, #carbons_private{}) andalso
not xmpp:has_subtag(Msg, #hint{type = 'no-copy'}) of
true ->
send_copies(JID, To, Msg, Direction);
false ->
ok
end,
Msg.
%%% Internal
%% Direction = received | sent <received xmlns='urn:xmpp:carbons:1'/>
-spec send_copies(jid(), jid(), message(), direction()) -> ok.
send_copies(JID, To, Msg, Direction)->
{U, S, R} = jid:tolower(JID),
PrioRes = ejabberd_sm:get_user_present_resources(U, S),
{_, AvailRs} = lists:unzip(PrioRes),
{MaxPrio, _MaxRes} = case catch lists:max(PrioRes) of
{Prio, Res} -> {Prio, Res};
_ -> {0, undefined}
end,
%% unavailable resources are handled like bare JIDs
IsBareTo = case {Direction, To} of
{received, #jid{lresource = <<>>}} -> true;
{received, #jid{lresource = LRes}} -> not lists:member(LRes, AvailRs);
_ -> false
end,
%% list of JIDs that should receive a carbon copy of this message (excluding the
%% receiver(s) of the original message
TargetJIDs = case {IsBareTo, Msg} of
{true, #message{meta = #{sm_copy := true}}} ->
%% The message was sent to our bare JID, and we currently have
%% multiple resources with the same highest priority, so the session
%% manager routes the message to each of them. We create carbon
%% copies only from one of those resources in order to avoid
%% duplicates.
[];
{true, _} ->
OrigTo = fun(Res) -> lists:member({MaxPrio, Res}, PrioRes) end,
[ {jid:make({U, S, CCRes}), CC_Version}
|| {CCRes, CC_Version} <- list(U, S),
lists:member(CCRes, AvailRs), not OrigTo(CCRes) ];
{false, _} ->
[ {jid:make({U, S, CCRes}), CC_Version}
|| {CCRes, CC_Version} <- list(U, S),
lists:member(CCRes, AvailRs), CCRes /= R ]
%TargetJIDs = lists:delete(JID, [ jid:make({U, S, CCRes}) || CCRes <- list(U, S) ]),
end,
lists:foreach(
fun({Dest, _Version}) ->
{_, _, Resource} = jid:tolower(Dest),
?DEBUG("Sending: ~p =/= ~p", [R, Resource]),
Sender = jid:make({U, S, <<>>}),
New = build_forward_packet(Msg, Sender, Dest, Direction),
ejabberd_router:route(xmpp:set_from_to(New, Sender, Dest))
end, TargetJIDs).
-spec build_forward_packet(message(), jid(), jid(), direction()) -> message().
build_forward_packet(#message{type = T} = Msg, Sender, Dest, Direction) ->
Forwarded = #forwarded{sub_els = [Msg]},
Carbon = case Direction of
sent -> #carbons_sent{forwarded = Forwarded};
received -> #carbons_received{forwarded = Forwarded}
end,
#message{from = Sender, to = Dest, type = T, sub_els = [Carbon],
meta = #{carbon_copy => true}}.
-spec enable(binary(), binary(), binary(), binary()) -> ok | {error, any()}.
enable(Host, U, R, CC)->
?DEBUG("Enabling carbons for ~ts@~ts/~ts", [U, Host, R]),
case ejabberd_sm:set_user_info(U, Host, R, carboncopy, CC) of
ok -> ok;
{error, Reason} = Err ->
?ERROR_MSG("Failed to enable carbons for ~ts@~ts/~ts: ~p",
[U, Host, R, Reason]),
Err
end.
-spec disable(binary(), binary(), binary()) -> ok | {error, any()}.
disable(Host, U, R)->
?DEBUG("Disabling carbons for ~ts@~ts/~ts", [U, Host, R]),
case ejabberd_sm:del_user_info(U, Host, R, carboncopy) of
ok -> ok;
{error, notfound} -> ok;
{error, Reason} = Err ->
?ERROR_MSG("Failed to disable carbons for ~ts@~ts/~ts: ~p",
[U, Host, R, Reason]),
Err
end.
-spec is_chat_message(message()) -> boolean().
is_chat_message(#message{type = chat}) ->
true;
is_chat_message(#message{type = normal, body = [_|_]}) ->
true;
is_chat_message(#message{type = Type} = Msg) when Type == chat;
Type == normal ->
has_chatstate(Msg) orelse xmpp:has_subtag(Msg, #receipt_response{});
is_chat_message(_) ->
false.
-spec is_received_muc_invite(message(), direction()) -> boolean().
is_received_muc_invite(_Msg, sent) ->
false;
is_received_muc_invite(Msg, received) ->
case xmpp:get_subtag(Msg, #muc_user{}) of
#muc_user{invites = [_|_]} ->
true;
_ ->
xmpp:has_subtag(Msg, #x_conference{jid = jid:make(<<"">>)})
end.
-spec is_received_muc_pm(jid(), message(), direction()) -> boolean().
is_received_muc_pm(#jid{lresource = <<>>}, _Msg, _Direction) ->
false;
is_received_muc_pm(_To, _Msg, sent) ->
false;
is_received_muc_pm(_To, Msg, received) ->
xmpp:has_subtag(Msg, #muc_user{}).
-spec has_chatstate(message()) -> boolean().
has_chatstate(#message{sub_els = Els}) ->
lists:any(fun(El) -> xmpp:get_ns(El) == ?NS_CHATSTATES end, Els).
-spec list(binary(), binary()) -> [{Resource :: binary(), Namespace :: binary()}].
list(User, Server) ->
lists:filtermap(
fun({Resource, Info}) ->
case lists:keyfind(carboncopy, 1, Info) of
{_, NS} -> {true, {Resource, NS}};
false -> false
end
end, ejabberd_sm:get_user_info(User, Server)).
depends(_Host, _Opts) ->
[].
mod_options(_) ->
[].
mod_doc() ->
#{desc =>
?T("The module implements https://xmpp.org/extensions/xep-0280.html"
"[XEP-0280: Message Carbons]. "
"The module broadcasts messages on all connected "
"user resources (devices).")}.
