From Lars Roland: add a preference to control whether, in the TCP

dissector, heuristic dissectors should be checked before, or after,
dissectors for specific port numbers.

Add a similar preference for UDP.

Clean up white space.

svn path=/trunk/; revision=8082

2 files changed, 42 insertions, 17 deletions

diff --git a/packet-tcp.c b/packet-tcp.c
index 5e6f8c07f2..eec2304bb5 100644
--- a/packet-tcp.c
+++ b/packet-tcp.c
@@ -1,7 +1,7 @@
 /* packet-tcp.c
  * Routines for TCP packet disassembly
  *
- * $Id: packet-tcp.c,v 1.199 2003/07/16 00:04:21 guy Exp $
+ * $Id: packet-tcp.c,v 1.200 2003/07/24 21:11:19 guy Exp $
  *
  * Ethereal - Network traffic analyzer
  * By Gerald Combs <gerald@ethereal.com>
@@ -1995,6 +1995,8 @@ static const ip_tcp_opt tcpopts[] = {
 /* separated into a stand alone routine to other protocol dissectors */
 /* can call to it, ie. socks	*/
 
+static gboolean try_heuristic_first = FALSE;
+
 void
 decode_tcp_ports(tvbuff_t *tvb, int offset, packet_info *pinfo,
 	proto_tree *tree, int src_port, int dst_port, guint32 nxtseq)
@@ -2009,7 +2011,6 @@ decode_tcp_ports(tvbuff_t *tvb, int offset, packet_info *pinfo,
     offset=scan_for_next_pdu(pinfo, offset, seq, nxtseq);
   }
 
-
   next_tvb = tvb_new_subset(tvb, offset, -1, -1);
 
 /* determine if this packet is part of a conversation and call dissector */
@@ -2019,6 +2020,12 @@ decode_tcp_ports(tvbuff_t *tvb, int offset, packet_info *pinfo,
 		src_port, dst_port, next_tvb, pinfo, tree))
     goto end_decode_tcp_ports;
 
+  if (try_heuristic_first) {
+    /* do lookup with the heuristic subdissector table */
+    if (dissector_try_heuristic(heur_subdissector_list, next_tvb, pinfo, tree))
+       goto end_decode_tcp_ports;
+  }
+
   /* Do lookups with the subdissector table.
      We try the port number with the lower value first, followed by the
      port number with the higher value.  This means that, for packets
@@ -2044,15 +2051,15 @@ decode_tcp_ports(tvbuff_t *tvb, int offset, packet_info *pinfo,
   if (low_port != 0 &&
       dissector_try_port(subdissector_table, low_port, next_tvb, pinfo, tree))
     goto end_decode_tcp_ports;
-
   if (high_port != 0 &&
       dissector_try_port(subdissector_table, high_port, next_tvb, pinfo, tree))
     goto end_decode_tcp_ports;
 
-  /* do lookup with the heuristic subdissector table */
-  if (dissector_try_heuristic(heur_subdissector_list, next_tvb, pinfo, tree))
-    goto end_decode_tcp_ports;
-
+  if (!try_heuristic_first) {
+    /* do lookup with the heuristic subdissector table */
+    if (dissector_try_heuristic(heur_subdissector_list, next_tvb, pinfo, tree))
+       goto end_decode_tcp_ports;
+  }
 
   /* Oh, well, we don't know this; dissect it as data. */
   call_dissector(data_handle,next_tvb, pinfo, tree);
@@ -2716,15 +2723,15 @@ proto_register_tcp(void)
 	tcp_module = prefs_register_protocol(proto_tcp, NULL);
 	prefs_register_bool_preference(tcp_module, "summary_in_tree",
 	    "Show TCP summary in protocol tree",
-"Whether the TCP summary line should be shown in the protocol tree",
+	    "Whether the TCP summary line should be shown in the protocol tree",
 	    &tcp_summary_in_tree);
 	prefs_register_bool_preference(tcp_module, "check_checksum",
 	    "Check the validity of the TCP checksum when possible",
-"Whether to check the validity of the TCP checksum",
+	    "Whether to check the validity of the TCP checksum",
 	    &tcp_check_checksum);
 	prefs_register_bool_preference(tcp_module, "desegment_tcp_streams",
 	    "Allow subdissector to desegment TCP streams",
-"Whether subdissector can request TCP streams to be desegmented",
+	    "Whether subdissector can request TCP streams to be desegmented",
 	    &tcp_desegment);
 	prefs_register_bool_preference(tcp_module, "analyze_sequence_numbers",
 	    "Analyze TCP sequence numbers",
@@ -2734,6 +2741,10 @@ proto_register_tcp(void)
 	    "Use relative sequence numbers",
 	    "Make the TCP dissector use relative sequence numbers instead of absolute ones. To use this option you must also enable \"Analyze TCP sequence numbers\".",
 	    &tcp_relative_seq);
+	prefs_register_bool_preference(tcp_module, "try_heuristic_first",
+	    "Try heuristic sub-dissectors first",
+	    "Try to decode a packet using an heuristic sub-dissector before using a sub-dissector registered to a specific port",
+	    &try_heuristic_first);
 
 	register_init_routine(tcp_analyze_seq_init);
 	register_init_routine(tcp_desegment_init);
diff --git a/packet-udp.c b/packet-udp.c
index e94ae781da..63c91a408f 100644
--- a/packet-udp.c
+++ b/packet-udp.c
@@ -1,7 +1,7 @@
 /* packet-udp.c
  * Routines for UDP packet disassembly
  *
- * $Id: packet-udp.c,v 1.108 2003/06/04 08:43:30 guy Exp $
+ * $Id: packet-udp.c,v 1.109 2003/07/24 21:11:20 guy Exp $
  *
  * Ethereal - Network traffic analyzer
  * By Gerald Combs <gerald@ethereal.com>
@@ -69,6 +69,8 @@ static dissector_handle_t data_handle;
 /* separated into a stand alone routine to other protocol dissectors */
 /* can call to it, ie. socks	*/
 
+static gboolean try_heuristic_first = FALSE;
+
 void
 decode_udp_ports(tvbuff_t *tvb, int offset, packet_info *pinfo,
 	proto_tree *tree, int uh_sport, int uh_dport)
@@ -85,6 +87,12 @@ decode_udp_ports(tvbuff_t *tvb, int offset, packet_info *pinfo,
 		uh_sport, uh_dport, next_tvb, pinfo, tree))
     return;
 
+  if (try_heuristic_first) {
+    /* do lookup with the heuristic subdissector table */
+    if (dissector_try_heuristic(heur_subdissector_list, next_tvb, pinfo, tree))
+      return;
+  }
+
   /* Do lookups with the subdissector table.
      We try the port number with the lower value first, followed by the
      port number with the higher value.  This means that, for packets
@@ -115,9 +123,11 @@ decode_udp_ports(tvbuff_t *tvb, int offset, packet_info *pinfo,
       dissector_try_port(udp_dissector_table, high_port, next_tvb, pinfo, tree))
     return;
 
-  /* do lookup with the heuristic subdissector table */
-  if (dissector_try_heuristic(heur_subdissector_list, next_tvb, pinfo, tree))
-    return;
+  if (!try_heuristic_first) {
+    /* do lookup with the heuristic subdissector table */
+    if (dissector_try_heuristic(heur_subdissector_list, next_tvb, pinfo, tree))
+      return;
+  }
 
   call_dissector(data_handle,next_tvb, pinfo, tree);
 }
@@ -304,9 +314,13 @@ proto_register_udp(void)
 	/* Register configuration preferences */
 	udp_module = prefs_register_protocol(proto_udp, NULL);
 	prefs_register_bool_preference(udp_module, "summary_in_tree",
-	"Show UDP summary in protocol tree",
-	"Whether the UDP summary line should be shown in the protocol tree",
-	&udp_summary_in_tree);
+	    "Show UDP summary in protocol tree",
+	    "Whether the UDP summary line should be shown in the protocol tree",
+	    &udp_summary_in_tree);
+	prefs_register_bool_preference(udp_module, "try_heuristic_first",
+	    "Try heuristic sub-dissectors first",
+	    "Try to decode a packet using an heuristic sub-dissector before using a sub-dissector registered to a specific port",
+	    &try_heuristic_first);
 }
 
 void