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Allow custom dissectors for BLE advertisement service UUIDs 

Add a dissector table "btcommon.eir_ad.entry.uuid_16", which behaves the same
way as the hard-coded GAEN (Google/Apple Exposure Notification) dissector does
today -- the table key is the 16-bit UUID
(https://www.bluetooth.com/specifications/assigned-numbers/), and the dissector
is given the corresponding service data.
This commit is contained in:
Maurice Lam 2022-09-30 22:13:12 -07:00 committed by AndersBroman
parent 420ec1511d
commit 460d4c85c2
2 changed files with 28 additions and 24 deletions
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2
epan/dissectors/packet-bluetooth.c
View File

@ -5185,7 +5185,7 @@ proto_register_btad_gaen(void)
void
proto_reg_handoff_btad_gaen(void)
{
dissector_add_for_decode_as("btcommon.eir_ad.manufacturer_company_id", btad_gaen);
dissector_add_string("btcommon.eir_ad.entry.uuid", "fd6f", btad_gaen);
}
/*

50
epan/dissectors/packet-bthci_cmd.c
View File

@ -1113,10 +1113,10 @@ static dissector_handle_t bthci_cmd_handle;
static dissector_handle_t btmesh_handle;
static dissector_handle_t btmesh_pbadv_handle;
static dissector_handle_t btmesh_beacon_handle;
static dissector_handle_t gaen_handle;
static dissector_table_t bluetooth_eir_ad_manufacturer_company_id;
static dissector_table_t bluetooth_eir_ad_tds_organization_id;
static dissector_table_t bluetooth_eir_ad_service_uuid;
wmem_tree_t *bthci_cmds = NULL;
@ -9180,13 +9180,8 @@ dissect_eir_ad_data(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, bluetoo
if (length - 2 > 0) {
uuid = get_bluetooth_uuid(tvb, offset-2, 2);
/* XXX A dissector table should be used here if we get many of these*/
if (uuid.bt_uuid == 0xFD6F) /* GAEN Identifier */
{
call_dissector(gaen_handle, tvb, pinfo, entry_tree);
}
else
{
if (!dissector_try_string(bluetooth_eir_ad_service_uuid, print_numeric_bluetooth_uuid(&uuid),
tvb_new_subset_length(tvb, offset, length - 2), pinfo, entry_tree, bluetooth_eir_ad_data)) {
proto_tree_add_item(entry_tree, hf_btcommon_eir_ad_service_data, tvb, offset, length - 2, ENC_NA);
}
offset += length - 2;
@ -9194,13 +9189,16 @@ dissect_eir_ad_data(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, bluetoo
break;
case 0x20: /* Service Data - 32 bit UUID */
uuid = get_bluetooth_uuid(tvb, offset, 4);
if (uuid.bt_uuid) {
sub_item = proto_tree_add_item(entry_tree, hf_btcommon_eir_ad_uuid_32, tvb, offset, 4, ENC_LITTLE_ENDIAN);
proto_item_append_text(sub_item, " (%s)", val_to_str_ext_const(uuid.bt_uuid, &bluetooth_uuid_vals_ext, "Unknown"));
}
else {
sub_item = proto_tree_add_item(entry_tree, hf_btcommon_eir_ad_custom_uuid_32, tvb, offset, 4, ENC_LITTLE_ENDIAN);
proto_item_append_text(sub_item, " (%s)", print_bluetooth_uuid(&uuid));
if (!dissector_try_string(bluetooth_eir_ad_service_uuid, print_numeric_bluetooth_uuid(&uuid),
tvb_new_subset_length(tvb, offset + 4, length - 4), pinfo, entry_tree, bluetooth_eir_ad_data)) {
if (uuid.bt_uuid) {
sub_item = proto_tree_add_item(entry_tree, hf_btcommon_eir_ad_uuid_32, tvb, offset, 4, ENC_LITTLE_ENDIAN);
proto_item_append_text(sub_item, " (%s)", val_to_str_ext_const(uuid.bt_uuid, &bluetooth_uuid_vals_ext, "Unknown"));
}
else {
sub_item = proto_tree_add_item(entry_tree, hf_btcommon_eir_ad_custom_uuid_32, tvb, offset, 4, ENC_LITTLE_ENDIAN);
proto_item_append_text(sub_item, " (%s)", print_bluetooth_uuid(&uuid));
}
}
offset += 4;
@ -9211,13 +9209,16 @@ dissect_eir_ad_data(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, bluetoo
break;
case 0x21: /* Service Data - 128 bit UUID */
uuid = get_bluetooth_uuid(tvb, offset, 16);
if (uuid.bt_uuid) {
sub_item = proto_tree_add_bytes_format_value(entry_tree, hf_btcommon_eir_ad_uuid_128, tvb, offset, 16, uuid.data, "%s", print_numeric_bluetooth_uuid(&uuid));
proto_item_append_text(sub_item, " (%s)", val_to_str_ext_const(uuid.bt_uuid, &bluetooth_uuid_vals_ext, "Unknown"));
}
else {
sub_item = proto_tree_add_bytes_format_value(entry_tree, hf_btcommon_eir_ad_custom_uuid_128, tvb, offset, 16, uuid.data, "%s", print_numeric_bluetooth_uuid(&uuid));
proto_item_append_text(sub_item, " (%s)", print_bluetooth_uuid(&uuid));
if (!dissector_try_string(bluetooth_eir_ad_service_uuid, print_numeric_bluetooth_uuid(&uuid),
tvb_new_subset_length(tvb, offset + 16, length - 16), pinfo, entry_tree, bluetooth_eir_ad_data)) {
if (uuid.bt_uuid) {
sub_item = proto_tree_add_bytes_format_value(entry_tree, hf_btcommon_eir_ad_uuid_128, tvb, offset, 16, uuid.data, "%s", print_numeric_bluetooth_uuid(&uuid));
proto_item_append_text(sub_item, " (%s)", val_to_str_ext_const(uuid.bt_uuid, &bluetooth_uuid_vals_ext, "Unknown"));
}
else {
sub_item = proto_tree_add_bytes_format_value(entry_tree, hf_btcommon_eir_ad_custom_uuid_128, tvb, offset, 16, uuid.data, "%s", print_numeric_bluetooth_uuid(&uuid));
proto_item_append_text(sub_item, " (%s)", print_bluetooth_uuid(&uuid));
}
}
offset += 16;
@ -10902,6 +10903,10 @@ proto_register_btcommon(void)
bluetooth_eir_ad_manufacturer_company_id = register_dissector_table("btcommon.eir_ad.manufacturer_company_id", "BT EIR/AD Manufacturer Company ID", proto_btcommon, FT_UINT16, BASE_HEX);
bluetooth_eir_ad_tds_organization_id = register_dissector_table("btcommon.eir_ad.tds_organization_id", "BT EIR/AD TDS Organization ID", proto_btcommon, FT_UINT8, BASE_HEX);
// Key for this table is the lower-case hex-representation of the service UUID. 16-bit UUIDs will have 4 characters, 32-bit UUIDs will have 8 characters.
// 128-bit UUIDs have 4 dashes in them, and therefore have 36 characters.
bluetooth_eir_ad_service_uuid = register_dissector_table("btcommon.eir_ad.entry.uuid", "BT EIR/AD Service UUID", proto_btcommon, FT_STRING, BASE_NONE);
register_decode_as(&bluetooth_eir_ad_manufacturer_company_id_da);
register_decode_as(&bluetooth_eir_ad_tds_organization_id_da);
}
@ -10912,7 +10917,6 @@ proto_reg_handoff_btcommon(void)
btmesh_handle = find_dissector("btmesh.msg");
btmesh_pbadv_handle = find_dissector("btmesh.pbadv");
btmesh_beacon_handle = find_dissector("btmesh.beacon");
gaen_handle = find_dissector("bluetooth.gaen");
}