[PATCH BlueZ v3 2/6] shared/gatt: Add timeout for secondary service discovery

[Martin BTS <martinbts@gmx.net>]

Some BLE devices do not respond to secondary service discovery
requests, causing the 30-second ATT timeout to fire and terminate the
connection. Add a 2-second timeout at the GATT client level that
cancels the pending ATT request and proceeds as if no secondary
services were found. This prevents the ATT timeout from killing the
connection while still giving well-behaved devices enough time to
respond.
---
 src/shared/gatt-client.c | 62 +++++++++++++++++++++++++++++++++++++++-
 1 file changed, 61 insertions(+), 1 deletion(-)

diff --git a/src/shared/gatt-client.c b/src/shared/gatt-client.c
index e1685809f..3e1c3e525 100644
--- a/src/shared/gatt-client.c
+++ b/src/shared/gatt-client.c
@@ -20,6 +20,7 @@
 #include "src/shared/queue.h"
 #include "src/shared/gatt-db.h"
 #include "src/shared/gatt-client.h"
+#include "src/shared/timeout.h"
 
 #include <assert.h>
 #include <limits.h>
@@ -33,6 +34,8 @@
 #define MIN(a, b) ((a) < (b) ? (a) : (b))
 #endif
 
+#define SECONDARY_DISC_TIMEOUT	2000	/* 2 seconds in ms */
+
 #define UUID_BYTES (BT_GATT_UUID_SIZE * sizeof(uint8_t))
 
 #define GATT_SVC_UUID	0x1801
@@ -114,6 +117,7 @@ struct bt_gatt_client {
 	unsigned int next_request_id;
 
 	struct bt_gatt_request *discovery_req;
+	unsigned int sec_disc_timeout_id;
 	unsigned int mtu_req_id;
 
 	/* Pending retry operation for DB out of sync handling */
@@ -1231,6 +1235,42 @@ static bool discovery_parse_services(struct discovery_op *op, bool primary,
 	return true;
 }
 
+struct sec_disc_timeout_data {
+	struct bt_gatt_client *client;
+	struct discovery_op *op;
+};
+
+static bool sec_disc_timeout_cb(void *user_data)
+{
+	struct sec_disc_timeout_data *data = user_data;
+	struct bt_gatt_client *client = data->client;
+	struct discovery_op *op = data->op;
+
+	DBG(client, "Secondary service discovery timed out, proceeding");
+
+	client->sec_disc_timeout_id = 0;
+
+	/* Cancel the pending ATT request before it hits the 30s ATT timeout */
+	if (client->discovery_req) {
+		bt_gatt_request_cancel(client->discovery_req);
+		bt_gatt_request_unref(client->discovery_req);
+		client->discovery_req = NULL;
+	}
+
+	/* Treat as success — no secondary services found */
+	discovery_op_complete(op, true, 0);
+
+	return false;
+}
+
+static void sec_disc_timeout_destroy(void *user_data)
+{
+	struct sec_disc_timeout_data *data = user_data;
+
+	discovery_op_unref(data->op);
+	free(data);
+}
+
 static void discover_secondary_cb(bool success, uint8_t att_ecode,
 						struct bt_gatt_result *result,
 						void *user_data)
@@ -1242,6 +1282,11 @@ static void discover_secondary_cb(bool success, uint8_t att_ecode,
 
 	discovery_req_clear(client);
 
+	if (client->sec_disc_timeout_id) {
+		timeout_remove(client->sec_disc_timeout_id);
+		client->sec_disc_timeout_id = 0;
+	}
+
 	if (!success) {
 		switch (att_ecode) {
 		case BT_ATT_ERROR_ATTRIBUTE_NOT_FOUND:
@@ -1354,8 +1399,18 @@ secondary:
 						discover_secondary_cb,
 						discovery_op_ref(op),
 						discovery_op_unref);
-	if (client->discovery_req)
+	if (client->discovery_req) {
+		struct sec_disc_timeout_data *td;
+
+		td = new0(struct sec_disc_timeout_data, 1);
+		td->client = client;
+		td->op = discovery_op_ref(op);
+		client->sec_disc_timeout_id = timeout_add(
+						SECONDARY_DISC_TIMEOUT,
+						sec_disc_timeout_cb, td,
+						sec_disc_timeout_destroy);
 		return;
+	}
 
 	DBG(client, "Failed to start secondary service discovery");
 
@@ -2822,6 +2877,11 @@ bool bt_gatt_client_cancel_all(struct bt_gatt_client *client)
 
 	queue_remove_all(client->pending_requests, NULL, NULL, cancel_pending);
 
+	if (client->sec_disc_timeout_id) {
+		timeout_remove(client->sec_disc_timeout_id);
+		client->sec_disc_timeout_id = 0;
+	}
+
 	if (client->discovery_req) {
 		bt_gatt_request_cancel(client->discovery_req);
 		bt_gatt_request_unref(client->discovery_req);
-- 
2.47.3