Bluetooth: Add support for appearance in scan rsp

This patch enables prepending appearance value to scan response data.
It also adds support for setting appearance value through mgmt command.
If currently advertised instance has apperance flag set it is expired
immediately.
Signed-off-by: Michał Narajowski <michal.narajowski@codecoup.pl>
Signed-off-by: Szymon Janc <szymon.janc@codecoup.pl>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

include/net/bluetooth/hci_core.h

@@ -211,6 +211,7 @@ struct hci_dev {
 	__u8		dev_name[HCI_MAX_NAME_LENGTH];
 	__u8		short_name[HCI_MAX_SHORT_NAME_LENGTH];
 	__u8		eir[HCI_MAX_EIR_LENGTH];
+	__u16		appearance;
 	__u8		dev_class[3];
 	__u8		major_class;
 	__u8		minor_class;

include/net/bluetooth/mgmt.h

@@ -598,6 +598,12 @@ struct mgmt_rp_read_ext_info {
 	__u8     eir[0];
 } __packed;
 
+#define MGMT_OP_SET_APPEARANCE		0x0043
+struct mgmt_cp_set_appearance {
+	__u16	appearance;
+} __packed;
+#define MGMT_SET_APPEARANCE_SIZE	2
+
 #define MGMT_EV_CMD_COMPLETE		0x0001
 struct mgmt_ev_cmd_complete {
 	__le16	opcode;

net/bluetooth/hci_request.c

@@ -1015,6 +1015,14 @@ static u8 create_instance_scan_rsp_data(struct hci_dev *hdev, u8 instance,
 
 	instance_flags = adv_instance->flags;
 
+	if ((instance_flags & MGMT_ADV_FLAG_APPEARANCE) && hdev->appearance) {
+		ptr[0] = 3;
+		ptr[1] = EIR_APPEARANCE;
+		put_unaligned_le16(hdev->appearance, ptr + 2);
+		scan_rsp_len += 4;
+		ptr += 4;
+	}
+
 	memcpy(ptr, adv_instance->scan_rsp_data,
 	       adv_instance->scan_rsp_len);
 

net/bluetooth/mgmt.c

@@ -105,6 +105,7 @@ static const u16 mgmt_commands[] = {
 	MGMT_OP_GET_ADV_SIZE_INFO,
 	MGMT_OP_START_LIMITED_DISCOVERY,
 	MGMT_OP_READ_EXT_INFO,
+	MGMT_OP_SET_APPEARANCE,
 };
 
 static const u16 mgmt_events[] = {
@@ -3143,6 +3144,34 @@ static int set_local_name(struct sock *sk, struct hci_dev *hdev, void *data,
 	return err;
 }
 
+static int set_appearance(struct sock *sk, struct hci_dev *hdev, void *data,
+			  u16 len)
+{
+	struct mgmt_cp_set_appearance *cp = data;
+	u16 apperance;
+	int err;
+
+	BT_DBG("");
+
+	apperance = le16_to_cpu(cp->appearance);
+
+	hci_dev_lock(hdev);
+
+	if (hdev->appearance != apperance) {
+		hdev->appearance = apperance;
+
+		if (hci_dev_test_flag(hdev, HCI_LE_ADV))
+			adv_expire(hdev, MGMT_ADV_FLAG_APPEARANCE);
+	}
+
+	err = mgmt_cmd_complete(sk, hdev->id, MGMT_OP_SET_APPEARANCE, 0, NULL,
+				0);
+
+	hci_dev_unlock(hdev);
+
+	return err;
+}
+
 static void read_local_oob_data_complete(struct hci_dev *hdev, u8 status,
 				         u16 opcode, struct sk_buff *skb)
 {
@@ -5918,6 +5947,7 @@ static u32 get_supported_adv_flags(struct hci_dev *hdev)
 	flags |= MGMT_ADV_FLAG_DISCOV;
 	flags |= MGMT_ADV_FLAG_LIMITED_DISCOV;
 	flags |= MGMT_ADV_FLAG_MANAGED_FLAGS;
+	flags |= MGMT_ADV_FLAG_APPEARANCE;
 	flags |= MGMT_ADV_FLAG_LOCAL_NAME;
 
 	if (hdev->adv_tx_power != HCI_TX_POWER_INVALID)
@@ -5999,6 +6029,9 @@ static bool tlv_data_is_valid(struct hci_dev *hdev, u32 adv_flags, u8 *data,
 		/* at least 1 byte of name should fit in */
 		if (adv_flags & MGMT_ADV_FLAG_LOCAL_NAME)
 			max_len -= 3;
+
+		if (adv_flags & MGMT_ADV_FLAG_APPEARANCE)
+			max_len -= 4;
 	}
 
 	if (len > max_len)
@@ -6335,6 +6368,9 @@ static u8 tlv_data_max_len(u32 adv_flags, bool is_adv_data)
 		/* at least 1 byte of name should fit in */
 		if (adv_flags & MGMT_ADV_FLAG_LOCAL_NAME)
 			max_len -= 3;
+
+		if (adv_flags & (MGMT_ADV_FLAG_APPEARANCE))
+			max_len -= 4;
 	}
 
 	return max_len;
@@ -6470,6 +6506,7 @@ static const struct hci_mgmt_handler mgmt_handlers[] = {
 	{ start_limited_discovery, MGMT_START_DISCOVERY_SIZE },
 	{ read_ext_controller_info,MGMT_READ_EXT_INFO_SIZE,
 						HCI_MGMT_UNTRUSTED },
+	{ set_appearance,	   MGMT_SET_APPEARANCE_SIZE },
 };
 
 void mgmt_index_added(struct hci_dev *hdev)