Combine Decode As and port preferences for tcp.port dissector table.

This patch introduces new APIs to allow dissectors to have a preference for
a (TCP) port, but the underlying data is actually part of Decode As functionality.
For now the APIs are intentionally separate from the regular APIs that register a
dissector within a dissector table.  It may be possible to eventually combine the
two so that all dissectors that register with a dissector table have an opportunity
to "automatically" have a preference to adjust the "table value" through the
preferences dialog.

The tcp.port dissector table was used as the guinea pig.  This will eventually be
expanded to other dissector tables as well (most notably UDP ports).  Some
dissectors that "shared" a TCP/UDP port preference were also converted. It also
removed the need for some preference callback functions (mostly when the callback
function was the proto_reg_handoff function) so there is cleanup around that.

Dissectors that has a port preference whose default was 0 were switched to using
the dissector_add_for_decode_as_with_preference API rather than dissector_add_uint_with_preference

Also added comments for TCP ports used that aren't IANA registered.

Change-Id: I99604f95d426ad345f4b494598d94178b886eb67
Reviewed-on: https://code.wireshark.org/review/17724
Reviewed-by: Michael Mann <mmann78@netscape.net>

1 files changed, 2 insertions, 9 deletions

diff --git a/epan/dissectors/packet-riemann.c b/epan/dissectors/packet-riemann.c
index 3ae459d0ff..5ee4093fd1 100644
--- a/epan/dissectors/packet-riemann.c
+++ b/epan/dissectors/packet-riemann.c
@@ -112,7 +112,6 @@ static int hf_riemann_state_state = -1;
 static int hf_riemann_state_once = -1;
 
 static guint udp_port_pref = 0;
-static guint tcp_port_pref = 0;
 
 static gint ett_riemann = -1;
 static gint ett_query = -1;
@@ -819,10 +818,6 @@ proto_register_riemann(void)
     prefs_register_uint_preference(riemann_module, "udp.port", "Riemann UDP Port",
             " riemann UDP port if other than the default",
             10, &udp_port_pref);
-
-    prefs_register_uint_preference(riemann_module, "tcp.port", "Riemann TCP Port",
-            " riemann TCP port if other than the default",
-            10, &tcp_port_pref);
 }
 
 void
@@ -830,20 +825,18 @@ proto_reg_handoff_riemann(void)
 {
     static gboolean initialized = FALSE;
     static dissector_handle_t riemann_udp_handle, riemann_tcp_handle;
-    static int current_udp_port, current_tcp_port;
+    static int current_udp_port;
 
     if (!initialized) {
         riemann_udp_handle = create_dissector_handle(dissect_riemann_udp, proto_riemann);
         riemann_tcp_handle = create_dissector_handle(dissect_riemann_tcp, proto_riemann);
+        dissector_add_for_decode_as_with_preference("tcp.port", riemann_tcp_handle);
         initialized = TRUE;
     } else {
         dissector_delete_uint("udp.port", current_udp_port, riemann_udp_handle);
-        dissector_delete_uint("tcp.port", current_tcp_port, riemann_tcp_handle);
     }
     current_udp_port = udp_port_pref;
     dissector_add_uint("udp.port", current_udp_port, riemann_udp_handle);
-    current_tcp_port = tcp_port_pref;
-    dissector_add_uint("tcp.port", current_tcp_port, riemann_tcp_handle);
 }
 
 /*