Dissectors don't need a journey of self discovery.

They already know who they are when they register themselves.  Saving the
handle then to avoid finding it later.
Not sure if this will increase unnecessary register_dissector functions
(instead of using create_dissector_handle in proto_reg_handoff function)
when other dissectors copy/paste, but it should make startup time
a few microseconds better.

Change-Id: I3839be791b32b84887ac51a6a65fb5733e9f1f43
Reviewed-on: https://code.wireshark.org/review/19481
Petri-Dish: Michael Mann <mmann78@netscape.net>
Tested-by: Petri Dish Buildbot <buildbot-no-reply@wireshark.org>
Reviewed-by: Anders Broman <a.broman58@gmail.com>

1 files changed, 8 insertions, 14 deletions

diff --git a/epan/dissectors/packet-rtp.c b/epan/dissectors/packet-rtp.c
index c64ece61d9..ee49751cc6 100644
--- a/epan/dissectors/packet-rtp.c
+++ b/epan/dissectors/packet-rtp.c
@@ -155,6 +155,9 @@ static dissector_handle_t classicstun_heur_handle;
 static dissector_handle_t stun_heur_handle;
 static dissector_handle_t t38_handle;
 static dissector_handle_t zrtp_handle;
+static dissector_handle_t rtp_rfc2198_handle;
+static dissector_handle_t rtp_hdr_ext_ed137_handle;
+static dissector_handle_t rtp_hdr_ext_ed137a_handle;
 
 static dissector_handle_t sprt_handle;
 static dissector_handle_t v150fw_handle;
@@ -3772,9 +3775,9 @@ proto_register_rtp(void)
     expert_rtp = expert_register_protocol(proto_rtp);
     expert_register_field_array(expert_rtp, ei, array_length(ei));
 
-    register_dissector("rtp", dissect_rtp, proto_rtp);
-    register_dissector("rtp.rfc2198", dissect_rtp_rfc2198, proto_rtp);
-    register_dissector("rtp.rfc4571", dissect_rtp_rfc4571, proto_rtp);
+    rtp_handle = register_dissector("rtp", dissect_rtp, proto_rtp);
+    rtp_rfc2198_handle = register_dissector("rtp.rfc2198", dissect_rtp_rfc2198, proto_rtp);
+    rtp_rfc4571_handle = register_dissector("rtp.rfc4571", dissect_rtp_rfc4571, proto_rtp);
 
     rtp_tap = register_tap("rtp");
 
@@ -3789,8 +3792,8 @@ proto_register_rtp(void)
     rtp_hdr_ext_rfc5285_dissector_table = register_dissector_table("rtp.ext.rfc5285.id",
                                     "RTP Generic header extension (RFC 5285)", proto_rtp, FT_UINT8, BASE_DEC);
 
-    register_dissector("rtp.ext.ed137", dissect_rtp_hdr_ext_ed137, proto_rtp);
-    register_dissector("rtp.ext.ed137a", dissect_rtp_hdr_ext_ed137a, proto_rtp);
+    rtp_hdr_ext_ed137_handle = register_dissector("rtp.ext.ed137", dissect_rtp_hdr_ext_ed137, proto_rtp);
+    rtp_hdr_ext_ed137a_handle = register_dissector("rtp.ext.ed137a", dissect_rtp_hdr_ext_ed137a, proto_rtp);
 
     rtp_module = prefs_register_protocol(proto_rtp, proto_reg_handoff_rtp);
 
@@ -3828,16 +3831,9 @@ void
 proto_reg_handoff_rtp(void)
 {
     static gboolean rtp_prefs_initialized = FALSE;
-    static dissector_handle_t rtp_rfc2198_handle;
     static guint rtp_saved_rfc2198_pt;
 
     if (!rtp_prefs_initialized) {
-        dissector_handle_t rtp_hdr_ext_ed137_handle;
-        dissector_handle_t rtp_hdr_ext_ed137a_handle;
-
-        rtp_handle = find_dissector("rtp");
-        rtp_rfc2198_handle = find_dissector("rtp.rfc2198");
-        rtp_rfc4571_handle = find_dissector("rtp.rfc4571");
 
         dissector_add_for_decode_as("udp.port", rtp_handle);
         dissector_add_for_decode_as("tcp.port", rtp_rfc4571_handle);
@@ -3846,8 +3842,6 @@ proto_reg_handoff_rtp(void)
         heur_dissector_add("stun", dissect_rtp_heur_app, "RTP over TURN", "rtp_stun", proto_rtp, HEURISTIC_DISABLE);
         heur_dissector_add("rtsp", dissect_rtp_heur_app, "RTP over RTSP", "rtp_rtsp", proto_rtp, HEURISTIC_DISABLE);
 
-        rtp_hdr_ext_ed137_handle = find_dissector("rtp.ext.ed137");
-        rtp_hdr_ext_ed137a_handle = find_dissector("rtp.ext.ed137a");
         dissector_add_uint("rtp.hdr_ext", RTP_ED137_SIG, rtp_hdr_ext_ed137_handle);
         dissector_add_uint("rtp.hdr_ext", RTP_ED137A_SIG, rtp_hdr_ext_ed137a_handle);
         dissector_add_for_decode_as("flip.payload", rtp_handle );