UAT: Have a combobox for Dissectors

Add a drop-down combobox for UATs, including User DLTs, that
have a choice of dissectors. Make the combobox editable, which
will provide suggestions, and pass things through to the existing
UAT validation for dissectors. (It's a very long list, especially
with 1717 entries, including 530 just from various BT GATT UUIDs,
so being able to still type it in seems useful.)

Dissectors are not protocols. Rename the UAT field from PROTO to
DISSECTOR where used. Update the column names and long descriptions
to use dissector instead of protocol in dissectors that used this.
There may at some point be UATs that want protocols instead of
dissectors, but that's not what the current behavior does and
none of the current dissectors that use the existing types want.

Update the documentation to use "dissector" instead of "protocol."
Put the names of the actual current three Ethernet dissectors.
Clarify that the "ip" dissector actually tries IPv4 and IPv6,
instead of just IPv4.

UAT entries are backwards and forwards compatible with versions
without this change.

Fix #18836.

8 files changed, 59 insertions, 35 deletions

diff --git a/docbook/wsug_src/wsug_customize.adoc b/docbook/wsug_src/wsug_customize.adoc
index 50a48dbbcd..49fbc74cda 100644
--- a/docbook/wsug_src/wsug_customize.adoc
+++ b/docbook/wsug_src/wsug_customize.adoc
@@ -1085,10 +1085,10 @@ sscop:nbap, ...)
 
 [#ChUserDLTsSection]
 
-=== User DLTs protocol table
+=== User DLTs dissector table
 
 When a pcap file uses one of the user DLTs (147 to 162) Wireshark uses this
-table to know which protocol(s) to use for each user DLT.
+table to know which dissector(s) to use for each user DLT.
 
 This table is a user table, as described in <<ChUserTable>>, with the
 following fields:
@@ -1096,23 +1096,23 @@ following fields:
 DLT::
 One of the user dlts.
 
-Payload protocol::
-This is the name of the payload protocol (the lowest layer in the packet data).
-(e.g., “eth” for ethernet, “ip” for IPv4)
+Payload dissector::
+This is the name of the payload dissector (the lowest layer in the packet data).
+(e.g., “eth_withfcs, "eth_withoutfcs”, and "eth_maybefcs" respectively for Ethernet frames that do, do not, or might possibly include the FCS at the end, “ip” for trying IPv4 then IPv6)
 
 Header size::
-If there is a header protocol (before the payload protocol) this tells which
-size this header is. A value of 0 disables the header protocol.
+If there is a header (before the payload) this tells which
+size this header is. A value of 0 disables the header dissector.
 
-Header protocol::
-The name of the header protocol to be used (uses “data” as default).
+Header dissector::
+The name of the header dissector to be used (uses “data” as default).
 
 Trailer size::
-If there is a trailer protocol (after the payload protocol) this tells which
-size this trailer is. A value of 0 disables the trailer protocol.
+If there is a trailer (after the payload) this tells which
+size this trailer is. A value of 0 disables the trailer dissector.
 
-Trailer protocol::
-The name of the trailer protocol to be used (uses “data” as default).
+Trailer dissector::
+The name of the trailer dissector to be used (uses “data” as default).
 
 [#ChProtobufSearchPaths]
 
diff --git a/epan/dissectors/packet-amqp.c b/epan/dissectors/packet-amqp.c
index 8ee9942295..3722f7c362 100644
--- a/epan/dissectors/packet-amqp.c
+++ b/epan/dissectors/packet-amqp.c
@@ -1635,7 +1635,7 @@ static void amqp_message_decode_free_cb(void *record)
 
 UAT_VS_DEF(message_decode, match_criteria, amqp_message_decode_t, guint32, MATCH_CRITERIA_EQUAL, "Equal to")
 UAT_CSTRING_CB_DEF(message_decode, topic_pattern, amqp_message_decode_t)
-UAT_PROTO_DEF(message_decode, payload_proto, payload_proto, payload_proto_name, amqp_message_decode_t)
+UAT_DISSECTOR_DEF(message_decode, payload_proto, payload_proto, payload_proto_name, amqp_message_decode_t)
 UAT_CSTRING_CB_DEF(message_decode, topic_more_info, amqp_message_decode_t)
 
 
@@ -13650,8 +13650,8 @@ proto_register_amqp(void)
     static uat_field_t amqp_message_decode_flds[] = {
         UAT_FLD_VS(message_decode, match_criteria, "Match criteria", match_criteria, "Match criteria"),
         UAT_FLD_CSTRING(message_decode, topic_pattern, "Topic pattern", "Pattern to match for the topic"),
-        UAT_FLD_PROTO(message_decode, payload_proto, "Payload protocol",
-                      "Protocol to be used for the message part of the matching topic"),
+        UAT_FLD_DISSECTOR(message_decode, payload_proto, "Payload dissector",
+                      "Dissector to be used for the message part of the matching topic"),
         UAT_FLD_CSTRING(message_decode, topic_more_info, "Additional Data", "Additional Data to pass to the dissector"),
         UAT_END_FIELDS
     };
diff --git a/epan/dissectors/packet-btrfcomm.c b/epan/dissectors/packet-btrfcomm.c
index 391fe86ba3..8d46c8fb37 100644
--- a/epan/dissectors/packet-btrfcomm.c
+++ b/epan/dissectors/packet-btrfcomm.c
@@ -134,12 +134,12 @@ static uat_rfcomm_channels_t  *rfcomm_channels          = NULL;
 static guint                  num_rfcomm_channels       = 0;
 
 UAT_DEC_CB_DEF(rfcomm_channels, channel, uat_rfcomm_channels_t)
-UAT_PROTO_DEF(rfcomm_channels, payload_proto, payload_proto, payload_proto_name, uat_rfcomm_channels_t)
+UAT_DISSECTOR_DEF(rfcomm_channels, payload_proto, payload_proto, payload_proto_name, uat_rfcomm_channels_t)
 
 static uat_field_t uat_rfcomm_channels_fields[] = {
     UAT_FLD_DEC(rfcomm_channels, channel, "RFCOMM Channel",
             "Range: 0-32"),
-    UAT_FLD_PROTO(rfcomm_channels, payload_proto, "Payload protocol",
+    UAT_FLD_DISSECTOR(rfcomm_channels, payload_proto, "Payload dissector",
             "Dissector name used to decode RFCOMM channel"),
     UAT_END_FIELDS
 };
diff --git a/epan/dissectors/packet-mqtt.c b/epan/dissectors/packet-mqtt.c
index e7d9b000e1..a360c3f6c6 100644
--- a/epan/dissectors/packet-mqtt.c
+++ b/epan/dissectors/packet-mqtt.c
@@ -683,7 +683,7 @@ static void mqtt_message_decode_free_cb(void *record)
 UAT_VS_DEF(message_decode, match_criteria, mqtt_message_decode_t, guint, MATCH_CRITERIA_EQUAL, "Equal to")
 UAT_CSTRING_CB_DEF(message_decode, topic_pattern, mqtt_message_decode_t)
 UAT_VS_DEF(message_decode, msg_decoding, mqtt_message_decode_t, guint, MSG_DECODING_NONE, "none")
-UAT_PROTO_DEF(message_decode, payload_proto, payload_proto, payload_proto_name, mqtt_message_decode_t)
+UAT_DISSECTOR_DEF(message_decode, payload_proto, payload_proto, payload_proto_name, mqtt_message_decode_t)
 
 static gboolean mqtt_user_decode_message(proto_tree *tree, proto_tree *mqtt_tree, packet_info *pinfo, const guint8 *topic_str, tvbuff_t *msg_tvb)
 {
@@ -1789,8 +1789,8 @@ void proto_register_mqtt(void)
     UAT_FLD_VS(message_decode, match_criteria, "Match criteria", match_criteria, "Match criteria"),
     UAT_FLD_CSTRING(message_decode, topic_pattern, "Topic pattern", "Pattern to match for the topic"),
     UAT_FLD_VS(message_decode, msg_decoding, "Decoding", msg_decoding, "Decode message before dissecting as protocol"),
-    UAT_FLD_PROTO(message_decode, payload_proto, "Payload protocol",
-                  "Protocol to be used for the message part of the matching topic"),
+    UAT_FLD_DISSECTOR(message_decode, payload_proto, "Payload dissector",
+                  "Dissector to be used for the message part of the matching topic"),
     UAT_END_FIELDS
   };
 
diff --git a/epan/dissectors/packet-user_encap.c b/epan/dissectors/packet-user_encap.c
index 6cc3ca71f8..164aca377b 100644
--- a/epan/dissectors/packet-user_encap.c
+++ b/epan/dissectors/packet-user_encap.c
@@ -210,11 +210,11 @@ static void user_free_cb(void* record)
 }
 
 UAT_VS_DEF(user_encap, encap, user_encap_t, guint, WTAP_ENCAP_USER0, ENCAP0_STR)
-UAT_PROTO_DEF(user_encap, payload_proto, payload_proto, payload_proto_name, user_encap_t)
+UAT_DISSECTOR_DEF(user_encap, payload_proto, payload_proto, payload_proto_name, user_encap_t)
 UAT_DEC_CB_DEF(user_encap, header_size, user_encap_t)
-UAT_PROTO_DEF(user_encap, header_proto, header_proto, header_proto_name, user_encap_t)
+UAT_DISSECTOR_DEF(user_encap, header_proto, header_proto, header_proto_name, user_encap_t)
 UAT_DEC_CB_DEF(user_encap, trailer_size, user_encap_t)
-UAT_PROTO_DEF(user_encap, trailer_proto, trailer_proto, trailer_proto_name, user_encap_t)
+UAT_DISSECTOR_DEF(user_encap, trailer_proto, trailer_proto, trailer_proto_name, user_encap_t)
 
 void proto_reg_handoff_user_encap(void)
 {
@@ -234,16 +234,16 @@ void proto_register_user_encap(void)
 
     static uat_field_t user_flds[] = {
         UAT_FLD_VS(user_encap,encap,"DLT",user_dlts,"The DLT"),
-        UAT_FLD_PROTO(user_encap,payload_proto,"Payload protocol",
-                      "Protocol to be used for the payload of this DLT"),
+        UAT_FLD_DISSECTOR(user_encap,payload_proto,"Payload dissector",
+                      "Dissector to be used for the payload of this DLT"),
         UAT_FLD_DEC(user_encap,header_size,"Header size",
                     "Size of an eventual header that precedes the actual payload, 0 means none"),
-        UAT_FLD_PROTO(user_encap,header_proto,"Header protocol",
-                      "Protocol to be used for the header (empty = data)"),
+        UAT_FLD_DISSECTOR(user_encap,header_proto,"Header dissector",
+                      "Dissector to be used for the header (empty = data)"),
         UAT_FLD_DEC(user_encap,trailer_size,"Trailer size",
                     "Size of an eventual trailer that follows the actual payload, 0 means none"),
-        UAT_FLD_PROTO(user_encap,trailer_proto,"Trailer protocol",
-                      "Protocol to be used for the trailer (empty = data)"),
+        UAT_FLD_DISSECTOR(user_encap,trailer_proto,"Trailer dissector",
+                      "Dissector to be used for the trailer (empty = data)"),
         UAT_END_FIELDS
     };
 
diff --git a/epan/uat.c b/epan/uat.c
index c0cd35199b..6aa3afc5e4 100644
--- a/epan/uat.c
+++ b/epan/uat.c
@@ -325,7 +325,9 @@ static void putfld(FILE* fp, void* rec, uat_field_t* f) {
         case PT_TXTMOD_DISPLAY_FILTER:
         case PT_TXTMOD_PROTO_FIELD:
         case PT_TXTMOD_COLOR:
-        case PT_TXTMOD_STRING: {
+        case PT_TXTMOD_STRING:
+        case PT_TXTMOD_DISSECTOR:
+        {
             guint i;
 
             putc('"',fp);
diff --git a/epan/uat.h b/epan/uat.h
index 1fe70900b8..54b9aff95a 100644
--- a/epan/uat.h
+++ b/epan/uat.h
@@ -202,6 +202,8 @@ typedef enum _uat_text_mode_t {
 	 */
 	PT_TXTMOD_ENUM,
 	/* Read/Writes/displays the string value (not number!) */
+	PT_TXTMOD_DISSECTOR,
+	/* Shows a combobox of dissectors */
 
 	PT_TXTMOD_COLOR,
 	/* Reads/Writes/display color in #RRGGBB format */
@@ -726,10 +728,10 @@ static void basename ## _ ## field_name ## _tostr_cb(void* rec, char** out_ptr,
 
 
 /*
- * PROTO macros
+ * DISSECTOR macros
  */
 
-#define UAT_PROTO_DEF(basename, field_name, dissector_field, name_field, rec_t) \
+#define UAT_DISSECTOR_DEF(basename, field_name, dissector_field, name_field, rec_t) \
 static void basename ## _ ## field_name ## _set_cb(void* rec, const char* buf, guint len, const void* UNUSED_PARAMETER(u1), const void* UNUSED_PARAMETER(u2)) {\
 	if (len) { \
 		gchar *tmp = g_strndup(buf,len); \
@@ -749,8 +751,8 @@ static void basename ## _ ## field_name ## _tostr_cb(void* rec, char** out_ptr,
 		*out_ptr = g_strdup(""); *out_len = 0; } }
 
 
-#define UAT_FLD_PROTO(basename,field_name,title,desc) \
-	{#field_name, title, PT_TXTMOD_STRING,{uat_fld_chk_proto,basename ## _ ## field_name ## _set_cb,basename ## _ ## field_name ## _tostr_cb},{0,0,0},0,desc,FLDFILL}
+#define UAT_FLD_DISSECTOR(basename,field_name,title,desc) \
+	{#field_name, title, PT_TXTMOD_DISSECTOR,{uat_fld_chk_proto,basename ## _ ## field_name ## _set_cb,basename ## _ ## field_name ## _tostr_cb},{0,0,0},0,desc,FLDFILL}
 
 /*
  * RANGE macros
diff --git a/ui/qt/models/uat_delegate.cpp b/ui/qt/models/uat_delegate.cpp
index 31481748a2..c01f8358b7 100644
--- a/ui/qt/models/uat_delegate.cpp
+++ b/ui/qt/models/uat_delegate.cpp
@@ -11,6 +11,7 @@
  */
 
 #include <ui/qt/models/uat_delegate.h>
+#include <epan/packet.h> // for get_dissector_names()
 #include "epan/value_string.h"
 #include <wsutil/ws_assert.h>
 #include <QRegularExpression>
@@ -77,6 +78,23 @@ QWidget *UatDelegate::createEditor(QWidget *parent, const QStyleOptionViewItem &
         break;
     }
 
+    case PT_TXTMOD_DISSECTOR:
+    {
+        QComboBox *cb_editor = new QComboBox(parent);
+        GList* dissector_names = get_dissector_names();
+        for (GList* l = dissector_names; l != NULL; l = l->next) {
+            const char *name = (const char *) l->data;
+            cb_editor->addItem(name, QVariant(name));
+        }
+        cb_editor->model()->sort(0);
+        g_list_free(dissector_names);
+        cb_editor->setInsertPolicy(QComboBox::NoInsert);
+        cb_editor->setEditable(true);
+        editor = cb_editor;
+        cb_editor->setMinimumWidth(cb_editor->minimumSizeHint().width());
+        break;
+    }
+
     case PT_TXTMOD_STRING:
         // TODO add a live validator? Should SyntaxLineEdit be used?
         editor = QStyledItemDelegate::createEditor(parent, option, index);
@@ -135,6 +153,7 @@ void UatDelegate::setEditorData(QWidget *editor, const QModelIndex &index) const
             qobject_cast<PathSelectionEdit *>(editor)->setPath(index.model()->data(index, Qt::EditRole).toString());
         break;
     case PT_TXTMOD_ENUM:
+    case PT_TXTMOD_DISSECTOR:
     {
         QComboBox *combobox = static_cast<QComboBox *>(editor);
         const QString &data = index.model()->data(index, Qt::EditRole).toString();
@@ -169,6 +188,7 @@ void UatDelegate::setModelData(QWidget *editor, QAbstractItemModel *model,
             const_cast<QAbstractItemModel *>(index.model())->setData(index, qobject_cast<PathSelectionEdit *>(editor)->path(), Qt::EditRole);
         break;
     case PT_TXTMOD_ENUM:
+    case PT_TXTMOD_DISSECTOR:
     {
         QComboBox *combobox = static_cast<QComboBox *>(editor);
         const QString &data = combobox->currentText();