From Marek Tews via https://bugs.wireshark.org/bugzilla/show_bug.cgi?id=6060

Enhance Universal Alcatel Protocol

Several fixes and heuristic version. You can also specify the ports (as in the previous version), if the heuristic version is not working properly.

svn path=/trunk/; revision=39691

1 files changed, 96 insertions, 28 deletions

diff --git a/epan/dissectors/packet-uaudp.c b/epan/dissectors/packet-uaudp.c
index dd5356f7eb..e4db699f91 100644
--- a/epan/dissectors/packet-uaudp.c
+++ b/epan/dissectors/packet-uaudp.c
@@ -1,6 +1,6 @@
 /* packet-uaudp.c
 * Routines for UA/UDP (Universal Alcatel UDP) packet dissection.
-* Copyright 2011
+* Copyright 2011, Marek Tews <marek@trx.com.pl>
 *
 * $Id$
 *
@@ -36,19 +36,18 @@
 #include <epan/packet.h>
 #include <epan/prefs.h>
 
+#include "packet-ua.h"
+
 /*
 * Here are the global variables associated with
 * the various user definable characteristics of the dissection
 */
-
+static gboolean use_heuristic_dissector = TRUE;
 static range_t *global_uaudp_port_range;
-static dissector_handle_t uaudp_handle;
-
-#define UAUDP_PORT_RANGE "5001, 32512"
-
 
 /* Define the UAUDP proto */
 static int proto_uaudp = -1;
+static dissector_handle_t uaudp_handle;
 static dissector_table_t uaudp_dissector_table;
 
 /* Define many header fields for UAUDP */
@@ -58,7 +57,6 @@ static int hf_uaudp_send = -1;
 
 /*
 * Define the trees for UAUDP
-* We need one tree for UAUDP itself and one for the pn-rt data status subtree
 */
 static int ett_uaudp_header = -1;
 
@@ -103,32 +101,95 @@ static int dissect_uaudp(tvbuff_t *pTvb, packet_info *pInfo, proto_tree *pTree)
     pHeaderSubTree = proto_item_add_subtree(pUAUDP, ett_uaudp_header);
     proto_tree_add_item(pHeaderSubTree, hf_uaudp_opcode, pTvb, 0, 1, ENC_BIG_ENDIAN);
 
-    if(u8Opcode == 7)
+    switch(u8Opcode)
     {
-        int iOffs = 1;
+    case 6:
+        {
+            /* Sequence Number (expected) */
+            proto_tree_add_item(pHeaderSubTree, hf_uaudp_expected, pTvb, 1, 2, ENC_BIG_ENDIAN);
+            break;
+        }
+    case 7:
+        {
+            int iOffs = 1;
+
+            /* Sequence Number (expected) */
+            proto_tree_add_item(pHeaderSubTree, hf_uaudp_expected, pTvb, iOffs, 2, ENC_BIG_ENDIAN);
+            iOffs += 2;
+
+            /* Sequence Number (sent) */
+            proto_tree_add_item(pHeaderSubTree, hf_uaudp_send, pTvb, iOffs, 2, ENC_BIG_ENDIAN);
+            iOffs += 2;
+
+            /* Create the tvbuffer for the next dissector */
+            if(nLen > iOffs)
+            {
+                if(dissector_try_uint(uaudp_dissector_table, 7, tvb_new_subset_remaining(pTvb, iOffs), pInfo, pTree))
+                    iOffs = nLen;
+                return iOffs;
+            }
+            else
+            {
+                col_append_str(pInfo->cinfo, COL_INFO, " ACK");
+            }
+            break;
+        }
+    }
+    return nLen;
+}
 
-        /* Sequence Number (expected) */
-        proto_tree_add_item(pHeaderSubTree, hf_uaudp_expected, pTvb, iOffs, 2, ENC_BIG_ENDIAN);
-        iOffs += 2;
+/*
+ * UAUDP-over-UDP
+ */
+static gboolean 
+dissect_uaudp_heur(tvbuff_t *pTvb, packet_info *pInfo, proto_tree *pTree)
+{
+    guint8 u8Opcode;
 
-        /* Sequence Number (sent) */
-        proto_tree_add_item(pHeaderSubTree, hf_uaudp_send, pTvb, iOffs, 2, ENC_BIG_ENDIAN);
-        iOffs += 2;
+    if(!use_heuristic_dissector)
+        return FALSE;
+
+    /* The opcode must be in range */
+    u8Opcode = tvb_get_guint8(pTvb, 0);
+    if(u8Opcode > 7)
+        return FALSE;
 
-        /* Create the tvbuffer for the next dissector */
-        if(nLen > iOffs)
+    /* The minimum length of a UAUDP message */
+    switch(u8Opcode)
+    {
+    case 4:
+    case 5:
         {
-            tvbuff_t *pTvbNext = tvb_new_subset_remaining(pTvb, iOffs);
-            if(dissector_try_uint(uaudp_dissector_table, 7, pTvbNext, pInfo, pTree))
-                iOffs = nLen;
-            return iOffs;
+            if(tvb_reported_length(pTvb) != 1)
+                return FALSE;
+            break;
         }
-        else
+    case 6:
         {
-            col_append_str(pInfo->cinfo, COL_INFO, " ACK");
+            if(tvb_reported_length(pTvb) != 3)
+                return FALSE;
+            break;
         }
+    case 7:
+        {
+            guint nLen = tvb_reported_length(pTvb);
+            if(nLen < 5)
+                return FALSE;
+
+            if(nLen > 5 && !is_ua(tvb_new_subset_remaining(pTvb, 5)))
+                return FALSE;
+
+            break;
+        }
+    /*
+     * There I met with other opcodes 
+     * and do not know how much data is transmitted.
+     */
+    default: return FALSE;
     }
-    return nLen;
+
+    dissect_uaudp(pTvb, pInfo, pTree);
+    return TRUE;
 }
 
 /* The registration hand-off routine is called at startup */
@@ -149,6 +210,11 @@ void proto_reg_handoff_uaudp(void)
 
     if (!uaudp_initialized)
     {
+        /*
+         * For UAUDP-over-UDP.
+         */
+        heur_dissector_add("udp", dissect_uaudp_heur, proto_uaudp);
+
         uaudp_handle = find_dissector("uaudp");
         uaudp_initialized = TRUE;
     }
@@ -198,13 +264,15 @@ void proto_register_uaudp(void)
     new_register_dissector("uaudp", dissect_uaudp, proto_uaudp);
 
     /* Register our configuration options */
-    range_convert_str(&global_uaudp_port_range, UAUDP_PORT_RANGE, MAX_UDP_PORT);
-
     uaudp_module = prefs_register_protocol(proto_uaudp, proto_reg_handoff_uaudp);
+    prefs_register_bool_preference(uaudp_module, "use_heuristic_dissector",
+        "Use heuristic dissector",
+        "Use to decode a packet a heuristic dissector. "
+        "Otherwise, they are decoded only those packets that will come from the specified ports.",
+        &use_heuristic_dissector);
     prefs_register_range_preference(uaudp_module, "udp_ports",
         "UAUDP port numbers",
-        "Port numbers used for UAUDP traffic "
-        "(default " UAUDP_PORT_RANGE ")",
+        "Port numbers used for UAUDP traffic (examples: 5001, 32512)",
         &global_uaudp_port_range, MAX_UDP_PORT);
 
     uaudp_dissector_table = register_dissector_table("uaudp.opcode", "UA/UDP Opcode", FT_UINT8, BASE_DEC);