Bluetooth: Add support for instance scan response

This patch implements setting the Scan Response data provided as part
of an advertising instance through the Add Advertising command.
Signed-off-by: Arman Uguray <armansito@chromium.org>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

net/bluetooth/mgmt.c

@@ -793,7 +793,7 @@ static struct mgmt_pending_cmd *pending_find_data(u16 opcode,
 	return mgmt_pending_find_data(HCI_CHANNEL_CONTROL, opcode, hdev, data);
 }
 
-static u8 create_scan_rsp_data(struct hci_dev *hdev, u8 *ptr)
+static u8 create_default_scan_rsp_data(struct hci_dev *hdev, u8 *ptr)
 {
 	u8 ad_len = 0;
 	size_t name_len;
@@ -819,7 +819,19 @@ static u8 create_scan_rsp_data(struct hci_dev *hdev, u8 *ptr)
 	return ad_len;
 }
 
-static void update_scan_rsp_data(struct hci_request *req)
+static u8 create_instance_scan_rsp_data(struct hci_dev *hdev, u8 *ptr)
+{
+	/* TODO: Set the appropriate entries based on advertising instance flags
+	 * here once flags other than 0 are supported.
+	 */
+	memcpy(ptr, hdev->adv_instance.scan_rsp_data,
+	       hdev->adv_instance.scan_rsp_len);
+
+	return hdev->adv_instance.scan_rsp_len;
+}
+
+static void update_scan_rsp_data_for_instance(struct hci_request *req,
+					      u8 instance)
 {
 	struct hci_dev *hdev = req->hdev;
 	struct hci_cp_le_set_scan_rsp_data cp;
@@ -830,10 +842,13 @@ static void update_scan_rsp_data(struct hci_request *req)
 
 	memset(&cp, 0, sizeof(cp));
 
-	len = create_scan_rsp_data(hdev, cp.data);
+	if (instance)
+		len = create_instance_scan_rsp_data(hdev, cp.data);
+	else
+		len = create_default_scan_rsp_data(hdev, cp.data);
 
 	if (hdev->scan_rsp_data_len == len &&
-	    memcmp(cp.data, hdev->scan_rsp_data, len) == 0)
+	    !memcmp(cp.data, hdev->scan_rsp_data, len))
 		return;
 
 	memcpy(hdev->scan_rsp_data, cp.data, sizeof(cp.data));
@@ -844,6 +859,25 @@ static void update_scan_rsp_data(struct hci_request *req)
 	hci_req_add(req, HCI_OP_LE_SET_SCAN_RSP_DATA, sizeof(cp), &cp);
 }
 
+static void update_scan_rsp_data(struct hci_request *req)
+{
+	struct hci_dev *hdev = req->hdev;
+	u8 instance;
+
+	/* The "Set Advertising" setting supersedes the "Add Advertising"
+	 * setting. Here we set the scan response data based on which
+	 * setting was set. When neither apply, default to the global settings,
+	 * represented by instance "0".
+	 */
+	if (hci_dev_test_flag(hdev, HCI_ADVERTISING_INSTANCE) &&
+	    !hci_dev_test_flag(hdev, HCI_ADVERTISING))
+		instance = 0x01;
+	else
+		instance = 0x00;
+
+	update_scan_rsp_data_for_instance(req, instance);
+}
+
 static u8 get_adv_discov_flags(struct hci_dev *hdev)
 {
 	struct mgmt_pending_cmd *cmd;
@@ -4547,6 +4581,7 @@ static int set_advertising(struct sock *sk, struct hci_dev *hdev, void *data,
 	if (val) {
 		/* Switch to instance "0" for the Set Advertising setting. */
 		update_adv_data_for_instance(&req, 0);
+		update_scan_rsp_data_for_instance(&req, 0);
 		enable_advertising(&req);
 	} else {
 		disable_advertising(&req);
@@ -6408,25 +6443,25 @@ static int read_adv_features(struct sock *sk, struct hci_dev *hdev,
 	return err;
 }
 
-static bool adv_data_is_valid(struct hci_dev *hdev, u32 adv_flags, u8 *adv_data,
-			      u8 adv_data_len)
+static bool tlv_data_is_valid(struct hci_dev *hdev, u32 adv_flags, u8 *data,
+			      u8 len)
 {
-	u8 max_adv_len = HCI_MAX_AD_LENGTH;
+	u8 max_len = HCI_MAX_AD_LENGTH;
 	int i, cur_len;
 
-	/* TODO: Correctly reduce adv_len based on adv_flags. */
+	/* TODO: Correctly reduce len based on adv_flags. */
 
-	if (adv_data_len > max_adv_len)
+	if (len > max_len)
 		return false;
 
-	/* Make sure that adv_data is correctly formatted. */
-	for (i = 0, cur_len = 0; i < adv_data_len; i += (cur_len + 1)) {
-		cur_len = adv_data[i];
+	/* Make sure that the data is correctly formatted. */
+	for (i = 0, cur_len = 0; i < len; i += (cur_len + 1)) {
+		cur_len = data[i];
 
 		/* If the current field length would exceed the total data
 		 * length, then it's invalid.
 		 */
-		if (i + cur_len >= adv_data_len)
+		if (i + cur_len >= len)
 			return false;
 	}
 
@@ -6526,7 +6561,9 @@ static int add_advertising(struct sock *sk, struct hci_dev *hdev,
 		goto unlock;
 	}
 
-	if (!adv_data_is_valid(hdev, flags, cp->data, cp->adv_data_len)) {
+	if (!tlv_data_is_valid(hdev, flags, cp->data, cp->adv_data_len) ||
+	    !tlv_data_is_valid(hdev, flags, cp->data + cp->adv_data_len,
+			       cp->scan_rsp_len)) {
 		err = mgmt_cmd_status(sk, hdev->id, MGMT_OP_ADD_ADVERTISING,
 				      MGMT_STATUS_INVALID_PARAMS);
 		goto unlock;
@@ -6570,6 +6607,7 @@ static int add_advertising(struct sock *sk, struct hci_dev *hdev,
 	hci_req_init(&req, hdev);
 
 	update_adv_data(&req);
+	update_scan_rsp_data(&req);
 	enable_advertising(&req);
 
 	err = hci_req_run(&req, add_advertising_complete);