Add support for dissector tables of type FT_NONE.

This is for dissectors that have "payloads" that don't have
a unique identifier to determine a sub dissector.

For the command line parameter -d, specifying a selector is no longer
required for dissector tables of type FT_NONE.

Change-Id: I3370d9e0dc147deeca4f26b842fe35dc3bda876e
Reviewed-on: https://code.wireshark.org/review/22574
Reviewed-by: Michael Mann <mmann78@netscape.net>

8 files changed, 185 insertions, 29 deletions

diff --git a/epan/decode_as.c b/epan/decode_as.c
index 30e60abd86..43405fa3e9 100644
--- a/epan/decode_as.c
+++ b/epan/decode_as.c
@@ -143,6 +143,9 @@ gboolean decode_as_default_reset(const gchar *name, gconstpointer pattern)
     case FT_UINT32:
         dissector_reset_uint(name, GPOINTER_TO_UINT(pattern));
         return TRUE;
+    case FT_NONE:
+        dissector_reset_payload(name);
+        return TRUE;
     case FT_STRING:
     case FT_STRINGZ:
     case FT_UINT_STRING:
@@ -167,6 +170,9 @@ gboolean decode_as_default_change(const gchar *name, gconstpointer pattern, gpoi
         case FT_UINT32:
             dissector_change_uint(name, GPOINTER_TO_UINT(pattern), *dissector);
             return TRUE;
+        case FT_NONE:
+            dissector_change_payload(name, *dissector);
+            return TRUE;
         case FT_STRING:
         case FT_STRINGZ:
         case FT_UINT_STRING:
@@ -349,6 +355,17 @@ decode_as_write_entry (const gchar *table_name, ftenum_t selector_type,
                  table_name, GPOINTER_TO_UINT(key), initial_proto_name,
                  current_proto_name);
         break;
+    case FT_NONE:
+        /*
+         * XXX - Just put a placeholder for the key value.  Currently
+         * FT_NONE dissector table uses a single uint value for
+         * a placeholder
+         */
+        fprintf (da_file,
+                 DECODE_AS_ENTRY ": %s,0,%s,%s\n",
+                 table_name, initial_proto_name,
+                 current_proto_name);
+        break;
 
     case FT_STRING:
     case FT_STRINGZ:
@@ -436,6 +453,11 @@ decode_build_reset_list (const gchar *table_name, ftenum_t selector_type,
         item->ddi_selector.sel_uint = GPOINTER_TO_UINT(key);
         break;
 
+    case FT_NONE:
+        /* Not really needed, but prevents the assert */
+        item->ddi_selector.sel_uint = 0;
+        break;
+
     case FT_STRING:
     case FT_STRINGZ:
     case FT_UINT_STRING:
@@ -470,6 +492,10 @@ decode_clear_all(void)
                                  item->ddi_selector.sel_uint);
             break;
 
+        case FT_NONE:
+            dissector_reset_payload(item->ddi_table_name);
+            break;
+
         case FT_STRING:
         case FT_STRINGZ:
         case FT_UINT_STRING:
diff --git a/epan/dissectors/packet-bthci_evt.c b/epan/dissectors/packet-bthci_evt.c
index c32e74c9de..6269e25602 100644
--- a/epan/dissectors/packet-bthci_evt.c
+++ b/epan/dissectors/packet-bthci_evt.c
@@ -918,6 +918,11 @@ static void bthci_evt_vendor_prompt(packet_info *pinfo _U_, gchar* result)
     g_snprintf(result, MAX_DECODE_AS_PROMPT_LEN, "Vendor as");
 }
 
+static gpointer bthci_evt_vendor_value(packet_info *pinfo _U_)
+{
+    return NULL;
+}
+
 static void add_opcode(wmem_list_t *opcode_list, guint16 opcode, enum command_status command_status) {
     opcode_list_data_t *opcode_list_data;
 
@@ -1924,7 +1929,7 @@ dissect_bthci_evt_command_status(tvbuff_t *tvb, int offset, packet_info *pinfo,
     if (ogf == HCI_OGF_VENDOR_SPECIFIC) {
         col_append_fstr(pinfo->cinfo, COL_INFO, " (Vendor Command 0x%04X [(opcode 0x%04X])", opcode & 0x03ff, opcode);
 
-        if (!dissector_try_uint_new(vendor_dissector_table, HCI_VENDOR_DEFAULT, tvb, pinfo, main_tree, TRUE, bluetooth_data)) {
+        if (!dissector_try_payload_new(vendor_dissector_table, tvb, pinfo, main_tree, TRUE, bluetooth_data)) {
             if (bluetooth_data) {
                 hci_vendor_data_t  *hci_vendor_data;
                 wmem_tree_key_t     key[3];
@@ -2755,7 +2760,7 @@ dissect_bthci_evt_command_complete(tvbuff_t *tvb, int offset,
     if (ogf == HCI_OGF_VENDOR_SPECIFIC) {
         col_append_fstr(pinfo->cinfo, COL_INFO, " (Vendor Command 0x%04X [opcode 0x%04X])", opcode & 0x03ff, opcode);
 
-        if (!dissector_try_uint_new(vendor_dissector_table, HCI_VENDOR_DEFAULT, tvb, pinfo, main_tree, TRUE, bluetooth_data)) {
+        if (!dissector_try_payload_new(vendor_dissector_table, tvb, pinfo, main_tree, TRUE, bluetooth_data)) {
             if (bluetooth_data) {
                 hci_vendor_data_t  *hci_vendor_data;
 
@@ -5516,7 +5521,7 @@ dissect_bthci_evt(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *dat
 
             break;
         case 0xff: /* Vendor-Specific */
-            if (!dissector_try_uint_new(vendor_dissector_table, HCI_VENDOR_DEFAULT, tvb, pinfo, tree, TRUE, bluetooth_data)) {
+            if (!dissector_try_payload_new(vendor_dissector_table, tvb, pinfo, tree, TRUE, bluetooth_data)) {
                 if (bluetooth_data) {
                     hci_vendor_data_t  *hci_vendor_data;
                     wmem_tree_key_t     key[3];
@@ -7971,6 +7976,15 @@ proto_register_bthci_evt(void)
         &ett_expert
     };
 
+    /* Decode As handling
+       This doesn't use register_decode_as_next_proto because it shares a dissector table
+       with "bthci_cmd.vendor" */
+    static build_valid_func bthci_evt_vendor_da_build_value[1] = {bthci_evt_vendor_value};
+    static decode_as_value_t bthci_evt_vendor_da_values = {bthci_evt_vendor_prompt, 1, bthci_evt_vendor_da_build_value};
+    static decode_as_t bthci_evt_vendor_da = {"bthci_cmd", "Vendor", "bthci_cmd.vendor", 1, 0, &bthci_evt_vendor_da_values, NULL, NULL,
+            decode_as_default_populate_list, decode_as_default_reset, decode_as_default_change, NULL};
+
+
     /* Register the protocol name and description */
     proto_bthci_evt = proto_register_protocol("Bluetooth HCI Event",
             "HCI_EVT", "bthci_evt");
@@ -7988,7 +8002,7 @@ proto_register_bthci_evt(void)
             "Bluetooth HCI version: 4.0 (Core) + Addendum 4",
             "Version of protocol supported by this dissector.");
 
-    register_decode_as_next_proto("bthci_cmd", "Vendor", "bthci_cmd.vendor", (build_label_func*)&bthci_evt_vendor_prompt);
+    register_decode_as(&bthci_evt_vendor_da);
 }
 
 
diff --git a/epan/packet.c b/epan/packet.c
index 542277db24..b416c8c03c 100644
--- a/epan/packet.c
+++ b/epan/packet.c
@@ -915,6 +915,9 @@ find_uint_dtbl_entry(dissector_table_t sub_dissectors, const guint32 pattern)
 		 * You can do a uint lookup in these tables.
 		 */
 		break;
+	case FT_NONE:
+		/* For now treat as uint */
+		break;
 
 	default:
 		/*
@@ -1856,6 +1859,36 @@ dissector_handle_t dissector_get_guid_handle(
 		return NULL;
 }
 
+/* Use the currently assigned payload dissector for the dissector table and,
+   if any, call the dissector with the arguments supplied, and return the
+   number of bytes consumed, otherwise return 0. */
+int dissector_try_payload(dissector_table_t sub_dissectors,
+    tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
+{
+	return dissector_try_uint(sub_dissectors, 0, tvb, pinfo, tree);
+}
+
+/* Use the currently assigned payload dissector for the dissector table and,
+   if any, call the dissector with the arguments supplied, and return the
+   number of bytes consumed, otherwise return 0. */
+int dissector_try_payload_new(dissector_table_t sub_dissectors,
+    tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, const gboolean add_proto_name, void *data)
+{
+	return dissector_try_uint_new(sub_dissectors, 0, tvb, pinfo, tree, add_proto_name, data);
+}
+
+/* Change the entry for a dissector in a payload (FT_NONE) dissector table
+   with a particular pattern to use a new dissector handle. */
+void dissector_change_payload(const char *abbrev, dissector_handle_t handle)
+{
+	dissector_change_uint(abbrev, 0, handle);
+}
+
+/* Reset payload (FT_NONE) dissector table to its initial value. */
+void dissector_reset_payload(const char *name)
+{
+	dissector_reset_uint(name, 0);
+}
 
 dissector_handle_t
 dtbl_entry_get_handle (dtbl_entry_t *dtbl_entry)
@@ -2349,6 +2382,18 @@ register_dissector_table(const char *name, const char *ui_name, const int proto,
 							       NULL,
 							       &g_free );
 		break;
+
+	case FT_NONE:
+		/* Dissector tables with FT_NONE don't have values associated with
+		   dissectors so this will always be a hash table size of 1 just
+		   to store the single dtbl_entry_t */
+		sub_dissectors->hash_func = g_direct_hash;
+		sub_dissectors->hash_table = g_hash_table_new_full( g_direct_hash,
+							       g_direct_equal,
+							       NULL,
+							       &g_free );
+		break;
+
 	default:
 		g_error("The dissector table %s (%s) is registering an unsupported type - are you using a buggy plugin?", name, ui_name);
 		g_assert_not_reached();
diff --git a/epan/packet.h b/epan/packet.h
index 84aa4912f5..ffe23285a4 100644
--- a/epan/packet.h
+++ b/epan/packet.h
@@ -367,6 +367,25 @@ WS_DLL_PUBLIC int dissector_try_guid_new(dissector_table_t sub_dissectors,
 WS_DLL_PUBLIC dissector_handle_t dissector_get_guid_handle(
     dissector_table_t const sub_dissectors, guid_key* guid_val);
 
+/* Use the currently assigned payload dissector for the dissector table and,
+   if any, call the dissector with the arguments supplied, and return the
+   number of bytes consumed, otherwise return 0. */
+WS_DLL_PUBLIC int dissector_try_payload(dissector_table_t sub_dissectors,
+    tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree);
+
+/* Use the currently assigned payload dissector for the dissector table and,
+   if any, call the dissector with the arguments supplied, and return the
+   number of bytes consumed, otherwise return 0. */
+WS_DLL_PUBLIC int dissector_try_payload_new(dissector_table_t sub_dissectors,
+    tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, const gboolean add_proto_name, void *data);
+
+/* Change the entry for a dissector in a payload (FT_NONE) dissector table
+   with a particular pattern to use a new dissector handle. */
+WS_DLL_PUBLIC void dissector_change_payload(const char *abbrev, dissector_handle_t handle);
+
+/* Reset payload (FT_NONE) dissector table to its initial value. */
+WS_DLL_PUBLIC void dissector_reset_payload(const char *name);
+
 /* Add a handle to the list of handles that *could* be used with this
    table.  That list is used by the "Decode As"/"-d" code in the UI. */
 WS_DLL_PUBLIC void dissector_add_for_decode_as(const char *name,
diff --git a/ui/decode_as_utils.c b/ui/decode_as_utils.c
index 173d82fe0b..0cf5942d57 100644
--- a/ui/decode_as_utils.c
+++ b/ui/decode_as_utils.c
@@ -187,7 +187,7 @@ gboolean decode_as_command_option(const gchar *cl_param)
     guint32                       selector, selector2;
     gchar                        *decoded_param;
     gchar                        *remaining_param;
-    gchar                        *selector_str;
+    gchar                        *selector_str = NULL;
     gchar                        *dissector_str;
     dissector_handle_t            dissector_matching;
     dissector_table_t             table_matching;
@@ -212,7 +212,14 @@ gboolean decode_as_command_option(const gchar *cl_param)
 
     remaining_param = strchr(table_name, '=');
     if (remaining_param == NULL) {
-        cmdarg_err("Parameter \"%s\" doesn't follow the template \"%s\"", cl_param, DECODE_AS_ARG_TEMPLATE);
+        /* Dissector tables of type FT_NONE aren't required to specify a value, so for now
+           just check for comma */
+        remaining_param = strchr(table_name, ',');
+        if (remaining_param == NULL) {
+            cmdarg_err("Parameter \"%s\" doesn't follow the template \"%s\"", cl_param, DECODE_AS_ARG_TEMPLATE);
+        } else {
+            *remaining_param = '\0'; /* Terminate the layer type string (table_name) where ',' was detected */
+        }
         /* If the argument does not follow the template, carry on anyway to check
         if the table name is at least correct.  If remaining_param is NULL,
         we'll exit anyway further down */
@@ -254,31 +261,34 @@ gboolean decode_as_command_option(const gchar *cl_param)
         return FALSE;
     }
 
-    if (*(remaining_param + 1) != '=') { /* Check for "==" and not only '=' */
-        cmdarg_err("WARNING: -d requires \"==\" instead of \"=\". Option will be treated as \"%s==%s\"", table_name, remaining_param + 1);
-    }
-    else {
-        remaining_param++; /* Move to the second '=' */
-        *remaining_param = '\0'; /* Remove the second '=' */
-    }
-    remaining_param++; /* Position after the layer type string */
+    dissector_table_selector_type = get_dissector_table_selector_type(table_name);
 
-    /* This section extracts a selector value (selector_str) from decoded_param */
+    if (dissector_table_selector_type != FT_NONE) {
+        if (*(remaining_param + 1) != '=') { /* Check for "==" and not only '=' */
+                cmdarg_err("WARNING: -d requires \"==\" instead of \"=\". Option will be treated as \"%s==%s\"", table_name, remaining_param + 1);
+        }
+        else {
+            remaining_param++; /* Move to the second '=' */
+            *remaining_param = '\0'; /* Remove the second '=' */
+        }
+        remaining_param++; /* Position after the layer type string */
 
-    selector_str = remaining_param; /* Next part starts with the selector number */
 
-    remaining_param = strchr(selector_str, ',');
-    if (remaining_param == NULL) {
-        cmdarg_err("Parameter \"%s\" doesn't follow the template \"%s\"", cl_param, DECODE_AS_ARG_TEMPLATE);
-        /* If the argument does not follow the template, carry on anyway to check
-        if the selector value is at least correct.  If remaining_param is NULL,
-        we'll exit anyway further down */
-    }
-    else {
-        *remaining_param = '\0'; /* Terminate the selector number string (selector_str) where ',' was detected */
-    }
+        /* This section extracts a selector value (selector_str) from decoded_param */
 
-    dissector_table_selector_type = get_dissector_table_selector_type(table_name);
+        selector_str = remaining_param; /* Next part starts with the selector number */
+
+        remaining_param = strchr(selector_str, ',');
+        if (remaining_param == NULL) {
+            cmdarg_err("Parameter \"%s\" doesn't follow the template \"%s\"", cl_param, DECODE_AS_ARG_TEMPLATE);
+            /* If the argument does not follow the template, carry on anyway to check
+            if the selector value is at least correct.  If remaining_param is NULL,
+            we'll exit anyway further down */
+        }
+        else {
+            *remaining_param = '\0'; /* Terminate the selector number string (selector_str) where ',' was detected */
+        }
+    }
 
     switch (dissector_table_selector_type) {
 
@@ -328,6 +338,10 @@ gboolean decode_as_command_option(const gchar *cl_param)
         /* The selector for this table is a string. */
         break;
 
+    case FT_NONE:
+        /* There is no selector for this table */
+        break;
+
     default:
         /* There are currently no dissector tables with any types other
         than the ones listed above. */
@@ -440,6 +454,11 @@ gboolean decode_as_command_option(const gchar *cl_param)
         dissector_change_string(table_name, selector_str, dissector_matching);
         break;
 
+    case FT_NONE:
+        /* Just directly set the dissector found. */
+        dissector_change_payload(table_name, dissector_matching);
+        break;
+
     default:
         /* There are currently no dissector tables with any types other
         than the ones listed above. */
diff --git a/ui/gtk/decode_as_dlg.c b/ui/gtk/decode_as_dlg.c
index 4e8292b439..86f231bc63 100644
--- a/ui/gtk/decode_as_dlg.c
+++ b/ui/gtk/decode_as_dlg.c
@@ -323,6 +323,10 @@ decode_build_show_list (const gchar *table_name, ftenum_t selector_type,
         selector_name = string1;
         break;
 
+    case FT_NONE:
+        selector_name = NULL;
+        break;
+
     case FT_STRING:
     case FT_STRINGZ:
     case FT_UINT_STRING:
diff --git a/ui/gtk/dissector_tables_dlg.c b/ui/gtk/dissector_tables_dlg.c
index e57a6a6eba..40289936df 100644
--- a/ui/gtk/dissector_tables_dlg.c
+++ b/ui/gtk/dissector_tables_dlg.c
@@ -153,6 +153,7 @@ decode_proto_add_to_list (const gchar *table_name _U_, ftenum_t selector_type,
 
         case FT_BYTES:
         case FT_GUID:
+        case FT_NONE:
             dissector_name_str = dissector_handle_get_dissector_name(handle);
             if (dissector_name_str == NULL)
                 dissector_name_str = "<Unknown>";
@@ -244,6 +245,7 @@ display_dissector_table_names(const char *table_name, const char *ui_name, void
             break;
         case FT_BYTES:
         case FT_GUID:
+        case FT_NONE:
             table_name_add_to_list(tree_info, dis_tbl_trees->custom_tree_wgt, table_name, ui_name);
             break;
         default:
diff --git a/ui/qt/models/decode_as_model.cpp b/ui/qt/models/decode_as_model.cpp
index 2c15e419fc..e4e654ddb1 100644
--- a/ui/qt/models/decode_as_model.cpp
+++ b/ui/qt/models/decode_as_model.cpp
@@ -61,14 +61,22 @@ Qt::ItemFlags DecodeAsModel::flags(const QModelIndex &index) const
     if (!index.isValid())
         return 0;
 
+    DecodeAsItem* item = decode_as_items_[index.row()];
+
     Qt::ItemFlags flags = QAbstractTableModel::flags(index);
     switch(index.column())
     {
     case DecodeAsModel::colTable:
-    case DecodeAsModel::colSelector:
     case DecodeAsModel::colProtocol:
         flags |= Qt::ItemIsEditable;
         break;
+    case DecodeAsModel::colSelector:
+        {
+        ftenum_t selector_type = get_dissector_table_selector_type(item->tableName_);
+        if (selector_type != FT_NONE)
+            flags |= Qt::ItemIsEditable;
+        break;
+        }
     }
 
     return flags;
@@ -126,7 +134,7 @@ QVariant DecodeAsModel::data(const QModelIndex &index, int role) const
 
             if (IS_FT_STRING(selector_type)) {
                 return tr("String");
-            } else {
+            } else if (IS_FT_UINT(selector_type)) {
                 QString type_desc = tr("Integer, base ");
                 switch (get_dissector_table_param(item->tableName_)) {
                 case BASE_OCT:
@@ -142,6 +150,8 @@ QVariant DecodeAsModel::data(const QModelIndex &index, int role) const
                     type_desc.append(tr("unknown"));
                 }
                 return type_desc;
+            } else if (selector_type == FT_NONE) {
+                return tr("<none>");
             }
         }
         case colDefault:
@@ -313,6 +323,9 @@ bool DecodeAsModel::insertRows(int row, int count, const QModelIndex &/*parent*/
                         }
 
                         dissector = dissector_get_default_uint_handle(entry->table_name, item->selectorUint_);
+                    } else if (selector_type == FT_NONE) {
+                        // There is no default for an FT_NONE dissector table
+                        dissector = NULL;
                     }
 
                     if (dissector != NULL) {
@@ -437,6 +450,10 @@ QString DecodeAsModel::entryString(const gchar *table_name, gpointer value)
         //TODO: DCE/RPC dissector table
         break;
 
+    case FT_NONE:
+        //doesn't really matter, just avoiding the assert
+        return "0";
+
     default:
         g_assert_not_reached();
         break;
@@ -519,6 +536,12 @@ void DecodeAsModel::gatherChangedEntries(const gchar *table_name,
     case FT_UINT32:
         model->changed_uint_entries_ << UintPair(table_name, GPOINTER_TO_UINT(key));
         break;
+    case FT_NONE:
+        //need to reset dissector table, so this needs to be in a changed list,
+        //might as well be the uint one.
+        model->changed_uint_entries_ << UintPair(table_name, 0);
+        break;
+
     case FT_STRING:
     case FT_STRINGZ:
     case FT_UINT_STRING:
@@ -597,6 +620,10 @@ void DecodeAsModel::applyChanges()
                     byteArray = item->selectorString_.toUtf8();
                     selector_value = (gpointer) byteArray.constData();
                     break;
+                case FT_NONE:
+                    //selector value is ignored, but dissector table needs to happen
+                    selector_value = NULL;
+                    break;
                 default:
                     continue;
                 }