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 <[e-mail]>
Signed-off-by: Szymon Janc <[e-mail]>
Signed-off-by: Marcel Holtmann <[e-mail]>

include/net/bluetooth/hci_core.h

···
 	__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

···
 	__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

···
 
 	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

···
 	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[] = {
···
 	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)
 {
···
 	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)
···
 		/* 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)
···
 		/* 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;
···
 	{ 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)