RTCP heuristic only matches odd port-number TURN ChannelData packets

RTCP can be carried within TURN CannelData messages, or STUN/TURN Send
messages. The TURN message can be in UDP or TCP, of any port number (by
default the even port 3478). So the RTCP heuristic dissector used inside the
TURN ChannelData/Send payload needs to match regardless of the port number of
the packet.

Bug: 11336
Change-Id: I155b87c3e666478d3245366784d7d4e49c8e42c8
Reviewed-on: https://code.wireshark.org/review/9624
Petri-Dish: Hadriel Kaplan <hadrielk@yahoo.com>
Reviewed-by: Evan Huus <eapache@gmail.com>
Tested-by: Petri Dish Buildbot <buildbot-no-reply@wireshark.org>
Reviewed-by: Michael Mann <mmann78@netscape.net>

1 files changed, 13 insertions, 7 deletions

diff --git a/epan/dissectors/packet-rtcp.c b/epan/dissectors/packet-rtcp.c
index 4f871d9dd8..ab07249ec9 100644
--- a/epan/dissectors/packet-rtcp.c
+++ b/epan/dissectors/packet-rtcp.c
@@ -812,12 +812,6 @@ dissect_rtcp_heur( tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *da
         return FALSE;
     }
 
-    /* Was it sent to an odd-numbered port? */
-    if ((pinfo->destport % 2) == 0)
-    {
-        return FALSE;   /* no */
-    }
-
     /* Look at first byte */
     first_byte = tvb_get_guint8(tvb, offset);
 
@@ -853,6 +847,18 @@ dissect_rtcp_heur( tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *da
     return TRUE;
 }
 
+static gboolean
+dissect_rtcp_heur_udp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data)
+{
+    /* Was it sent to an odd-numbered port? */
+    if ((pinfo->destport % 2) == 0)
+    {
+        return FALSE;   /* no */
+    }
+
+    return dissect_rtcp_heur(tvb, pinfo, tree, data);
+}
+
 /* Dissect the length field. Append to this field text indicating the number of
    actual bytes this translates to (i.e. (raw value + 1) * 4) */
 static int dissect_rtcp_length_field( proto_tree *tree, tvbuff_t *tvb, int offset)
@@ -6531,7 +6537,7 @@ proto_reg_handoff_rtcp(void)
     dissector_add_for_decode_as("udp.port", rtcp_handle);
     dissector_add_for_decode_as("flip.payload", rtcp_handle );
 
-    heur_dissector_add( "udp", dissect_rtcp_heur, "RTCP over UDP", "rtcp_udp", proto_rtcp);
+    heur_dissector_add( "udp", dissect_rtcp_heur_udp, "RTCP over UDP", "rtcp_udp", proto_rtcp);
     heur_dissector_add("stun", dissect_rtcp_heur, "RTCP over TURN", "rtcp_stun", proto_rtcp);
 }