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From:   Alain Michaud <alainm@chromium.org>
To:     linux-bluetooth@vger.kernel.org
Cc:     Alain Michaud <alainm@chromium.org>,
        Miao-chen Chou <mcchou@chromium.org>
Subject: [Bluez PATCH v2] gatt: Support DeviceInfo Service when vid/pid is specified
Date:   Fri, 17 Jul 2020 14:40:07 +0000
Message-Id: <20200717144007.3160721-1-alainm@chromium.org>
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Sender: linux-bluetooth-owner@vger.kernel.org
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This patch adds support for the PNPID characteristic when configured in
main.conf.

This was validated as read correclty both by manually reading the valud
and confirming in the Ellisys Analyzer.

ATT Read (PnP ID: Source=Bluetooth ID, Vendor=224, Product=50181,
ATT Read Response Packet (Source=Bluetooth ID, Vendor=224,
Product=50181, Version=86)     | OK     | 7 bytes (01 E0 00 05 C4 56 00)

Reviewed-by: Miao-chen Chou <mcchou@chromium.org>
Signed-off-by: Alain Michaud <alainm@chromium.org>
---
I admit I don't know how to quantify the compatibility risk with adding
the Device Info Service if the DeviceID is specified.  I can see that
some system may be configured with an app to publish the DIS and this
may break it.

If the community feels it is necessary, I can include a DeviceIdOverLE
configuration which defaults to false in main.conf to address this
compatibility risk.

Changes in v2:
 - Removing file I didn't intend to commit (peripheral/gatt.c)

 src/gatt-database.c | 41 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 41 insertions(+)

diff --git a/src/gatt-database.c b/src/gatt-database.c
index 95ba39897..07d567078 100644
--- a/src/gatt-database.c
+++ b/src/gatt-database.c
@@ -57,6 +57,7 @@
 
 #define UUID_GAP	0x1800
 #define UUID_GATT	0x1801
+#define UUID_DIS	0x180a
 
 #ifndef MIN
 #define MIN(a, b) ((a) < (b) ? (a) : (b))
@@ -1233,11 +1234,51 @@ static void populate_gatt_service(struct btd_gatt_database *database)
 	database_add_record(database, service);
 }
 
+static void device_info_read_pnp_id_cb(struct gatt_db_attribute *attrib,
+					unsigned int id, uint16_t offset,
+					uint8_t opcode, struct bt_att *att,
+					void *user_data)
+{
+	uint8_t pdu[7];
+
+	pdu[0] = main_opts.did_source;
+	put_le16(main_opts.did_vendor, &pdu[1]);
+	put_le16(main_opts.did_product, &pdu[3]);
+	put_le16(main_opts.did_version, &pdu[5]);
+
+	gatt_db_attribute_read_result(attrib, id, 0, pdu, sizeof(pdu));
+}
+
+static void populate_devinfo_service(struct btd_gatt_database *database)
+{
+	struct gatt_db_attribute *service;
+	bt_uuid_t uuid;
+
+	bt_uuid16_create(&uuid, UUID_DIS);
+	service = gatt_db_add_service(database->db, &uuid, true, 3);
+
+	if (main_opts.did_source > 0) {
+		bt_uuid16_create(&uuid, GATT_CHARAC_PNP_ID);
+		gatt_db_service_add_characteristic(service, &uuid,
+						BT_ATT_PERM_READ,
+						BT_GATT_CHRC_PROP_READ,
+						device_info_read_pnp_id_cb,
+						NULL, database);
+	}
+
+	gatt_db_service_set_active(service, true);
+
+	database_add_record(database, service);
+}
 
 static void register_core_services(struct btd_gatt_database *database)
 {
 	populate_gap_service(database);
 	populate_gatt_service(database);
+
+	if (main_opts.did_source > 0)
+		populate_devinfo_service(database);
+
 }
 
 static void conf_cb(void *user_data)
-- 
2.28.0.rc0.105.gf9edc3c819-goog