Bluetooth: advmon offload MSFT handle filter enablement

Implements the feature to disable/enable the filter used for
advertising monitor on MSFT controller, effectively have the same
effect as "remove all monitors" and "add all previously removed
monitors".

This feature would be needed when suspending, where we would not want
to get packets from anything outside the allowlist. Note that the
integration with the suspending part is not included in this patch.

Signed-off-by: Archie Pusaka <apusaka@chromium.org>
Reviewed-by: Miao-chen Chou <mcchou@chromium.org>
Reviewed-by: Yun-Hao Chung <howardchung@google.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

net/bluetooth/msft.c

@@ -69,6 +69,17 @@ struct msft_rp_le_cancel_monitor_advertisement {
 	__u8 sub_opcode;
 } __packed;
 
+#define MSFT_OP_LE_SET_ADVERTISEMENT_FILTER_ENABLE	0x05
+struct msft_cp_le_set_advertisement_filter_enable {
+	__u8 sub_opcode;
+	__u8 enable;
+} __packed;
+
+struct msft_rp_le_set_advertisement_filter_enable {
+	__u8 status;
+	__u8 sub_opcode;
+} __packed;
+
 struct msft_monitor_advertisement_handle_data {
 	__u8  msft_handle;
 	__u16 mgmt_handle;
@@ -83,6 +94,7 @@ struct msft_data {
 	__u16 pending_add_handle;
 	__u16 pending_remove_handle;
 	__u8 reregistering;
+	__u8 filter_enabled;
 };
 
 static int __msft_add_monitor_pattern(struct hci_dev *hdev,
@@ -190,6 +202,7 @@ void msft_do_open(struct hci_dev *hdev)
 
 	if (msft_monitor_supported(hdev)) {
 		msft->reregistering = true;
+		msft_set_filter_enable(hdev, true);
 		reregister_monitor_on_restart(hdev, 0);
 	}
 }
@@ -395,6 +408,40 @@ done:
 	hci_remove_adv_monitor_complete(hdev, status);
 }
 
+static void msft_le_set_advertisement_filter_enable_cb(struct hci_dev *hdev,
+						       u8 status, u16 opcode,
+						       struct sk_buff *skb)
+{
+	struct msft_cp_le_set_advertisement_filter_enable *cp;
+	struct msft_rp_le_set_advertisement_filter_enable *rp;
+	struct msft_data *msft = hdev->msft_data;
+
+	rp = (struct msft_rp_le_set_advertisement_filter_enable *)skb->data;
+	if (skb->len < sizeof(*rp))
+		return;
+
+	/* Error 0x0C would be returned if the filter enabled status is
+	 * already set to whatever we were trying to set.
+	 * Although the default state should be disabled, some controller set
+	 * the initial value to enabled. Because there is no way to know the
+	 * actual initial value before sending this command, here we also treat
+	 * error 0x0C as success.
+	 */
+	if (status != 0x00 && status != 0x0C)
+		return;
+
+	hci_dev_lock(hdev);
+
+	cp = hci_sent_cmd_data(hdev, hdev->msft_opcode);
+	msft->filter_enabled = cp->enable;
+
+	if (status == 0x0C)
+		bt_dev_warn(hdev, "MSFT filter_enable is already %s",
+			    cp->enable ? "on" : "off");
+
+	hci_dev_unlock(hdev);
+}
+
 static bool msft_monitor_rssi_valid(struct adv_monitor *monitor)
 {
 	struct adv_rssi_thresholds *r = &monitor->rssi;
@@ -531,3 +578,23 @@ int msft_remove_monitor(struct hci_dev *hdev, struct adv_monitor *monitor,
 
 	return err;
 }
+
+int msft_set_filter_enable(struct hci_dev *hdev, bool enable)
+{
+	struct msft_cp_le_set_advertisement_filter_enable cp;
+	struct hci_request req;
+	struct msft_data *msft = hdev->msft_data;
+	int err;
+
+	if (!msft)
+		return -EOPNOTSUPP;
+
+	cp.sub_opcode = MSFT_OP_LE_SET_ADVERTISEMENT_FILTER_ENABLE;
+	cp.enable = enable;
+
+	hci_req_init(&req, hdev);
+	hci_req_add(&req, hdev->msft_opcode, sizeof(cp), &cp);
+	err = hci_req_run_skb(&req, msft_le_set_advertisement_filter_enable_cb);
+
+	return err;
+}

net/bluetooth/msft.h

@@ -20,6 +20,7 @@ __u64 msft_get_features(struct hci_dev *hdev);
 int msft_add_monitor_pattern(struct hci_dev *hdev, struct adv_monitor *monitor);
 int msft_remove_monitor(struct hci_dev *hdev, struct adv_monitor *monitor,
 			u16 handle);
+int msft_set_filter_enable(struct hci_dev *hdev, bool enable);
 
 #else
 
@@ -45,4 +46,9 @@ static inline int msft_remove_monitor(struct hci_dev *hdev,
 	return -EOPNOTSUPP;
 }
 
+static inline int msft_set_filter_enable(struct hci_dev *hdev, bool enable)
+{
+	return -EOPNOTSUPP;
+}
+
 #endif