From 4d5eab66625b9693933bdea8abbf5d25799f1fde Mon Sep 17 00:00:00 2001
From: Holger Weiss <holger@zedat.fu-berlin.de>
Date: Fri, 3 Jun 2016 20:28:48 +0200
Subject: [PATCH] Unwrap carbon copies when checking for chat states

Detect standalone chat states that were carbon-copied.
---
 src/jlib.erl             | 45 +++++++++++++++++++++++++++++++++++++++-
 src/mod_client_state.erl |  2 +-
 src/mod_offline.erl      |  3 ++-
 3 files changed, 47 insertions(+), 3 deletions(-)

diff --git a/src/jlib.erl b/src/jlib.erl
index 8fe2b9774..42ac4bff3 100644
--- a/src/jlib.erl
+++ b/src/jlib.erl
@@ -43,7 +43,7 @@
 	 get_iq_namespace/1, iq_query_info/1,
 	 iq_query_or_response_info/1, is_iq_request_type/1,
 	 iq_to_xml/1, parse_xdata_submit/1,
-	 is_standalone_chat_state/1,
+	 unwrap_carbon/1, is_standalone_chat_state/1,
 	 add_delay_info/3, add_delay_info/4,
 	 timestamp_to_legacy/1, timestamp_to_iso_basic/1, timestamp_to_iso/2,
 	 now_to_utc_string/1, now_to_local_string/1,
@@ -529,6 +529,49 @@ rsm_encode_count(Count, Arr) ->
 	    children = [{xmlcdata, i2l(Count)}]}
      | Arr].
 
+-spec unwrap_carbon(xmlel()) -> xmlel().
+
+unwrap_carbon(#xmlel{name = <<"message">>} = Stanza) ->
+    case unwrap_carbon(Stanza, <<"sent">>) of
+      #xmlel{} = Payload ->
+	  Payload;
+      false ->
+	  case unwrap_carbon(Stanza, <<"received">>) of
+	    #xmlel{} = Payload ->
+		Payload;
+	    false ->
+		Stanza
+	  end
+    end;
+unwrap_carbon(Stanza) -> Stanza.
+
+-spec unwrap_carbon(xmlel(), binary()) -> xmlel() | false.
+
+unwrap_carbon(Stanza, Direction) ->
+    case fxml:get_subtag(Stanza, Direction) of
+      #xmlel{name = Direction, attrs = Attrs} = El ->
+	  case fxml:get_attr_s(<<"xmlns">>, Attrs) of
+	    NS when NS == ?NS_CARBONS_2;
+		    NS == ?NS_CARBONS_1 ->
+		case fxml:get_subtag_with_xmlns(El, <<"forwarded">>,
+						?NS_FORWARD) of
+		  #xmlel{children = Els} ->
+		      case fxml:remove_cdata(Els) of
+			[#xmlel{} = Payload] ->
+			    Payload;
+			_ ->
+			    false
+		      end;
+		  false ->
+		      false
+		end;
+	    _NS ->
+		false
+	  end;
+      false ->
+	  false
+    end.
+
 -spec is_standalone_chat_state(xmlel()) -> boolean().
 
 is_standalone_chat_state(#xmlel{name = <<"message">>, children = Els}) ->
diff --git a/src/mod_client_state.erl b/src/mod_client_state.erl
index 0d3a289a3..6b79aec0d 100644
--- a/src/mod_client_state.erl
+++ b/src/mod_client_state.erl
@@ -165,7 +165,7 @@ filter_presence(Acc, _Host, _Stanza) -> Acc.
 
 filter_chat_states({C2SState, _OutStanzas} = Acc, Host,
 		   #xmlel{name = <<"message">>} = Stanza) ->
-    case jlib:is_standalone_chat_state(Stanza) of
+    case jlib:is_standalone_chat_state(jlib:unwrap_carbon(Stanza)) of
       true ->
 	  ?DEBUG("Got standalone chat state notification", []),
 	  queue_add(chatstate, Stanza, Host, C2SState);
diff --git a/src/mod_offline.erl b/src/mod_offline.erl
index 4d8aba762..74fbcd99b 100644
--- a/src/mod_offline.erl
+++ b/src/mod_offline.erl
@@ -455,7 +455,8 @@ need_to_store(LServer, Packet) ->
 				false ->
 				    fxml:get_subtag(Packet, <<"body">>) /= false;
 				unless_chat_state ->
-				    not jlib:is_standalone_chat_state(Packet);
+				    not jlib:is_standalone_chat_state(
+					  jlib:unwrap_carbon(Packet));
 				true ->
 				    true
 			    end