Bluetooth: Fix local name in scan rsp

Use complete name if it fits. If not and there is short name
check if it fits. If not then use shortened name as prefix
of complete name.
Signed-off-by: Michał Narajowski <michal.narajowski@codecoup.pl>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

net/bluetooth/hci_request.c

@@ -973,25 +973,48 @@ void __hci_req_enable_advertising(struct hci_request *req)
 
 static u8 append_local_name(struct hci_dev *hdev, u8 *ptr, u8 ad_len)
 {
-	size_t name_len;
+	size_t complete_len;
+	size_t short_len;
 	int max_len;
 
 	max_len = HCI_MAX_AD_LENGTH - ad_len - 2;
-	name_len = strlen(hdev->dev_name);
-	if (name_len > 0 && max_len > 0) {
+	complete_len = strlen(hdev->dev_name);
+	short_len = strlen(hdev->short_name);
 
-		if (name_len > max_len) {
-			name_len = max_len;
-			ptr[1] = EIR_NAME_SHORT;
-		} else
-			ptr[1] = EIR_NAME_COMPLETE;
+	/* no space left for name */
+	if (max_len < 1)
+		return ad_len;
 
-		ptr[0] = name_len + 1;
+	/* no name set */
+	if (!complete_len)
+		return ad_len;
 
-		memcpy(ptr + 2, hdev->dev_name, name_len);
+	/* complete name fits and is eq to max short name len or smaller */
+	if (complete_len <= max_len &&
+	    complete_len <= HCI_MAX_SHORT_NAME_LENGTH) {
+		ptr[0] = complete_len + 1;
+		ptr[1] = EIR_NAME_COMPLETE;
+		memcpy(ptr + 2, hdev->dev_name, complete_len);
 
-		ad_len += (name_len + 2);
-		ptr += (name_len + 2);
+		return ad_len + complete_len + 2;
+	}
+
+	/* short name set and fits */
+	if (short_len && short_len <= max_len) {
+		ptr[0] = short_len + 1;
+		ptr[1] = EIR_NAME_SHORT;
+		memcpy(ptr + 2, hdev->short_name, short_len);
+
+		return ad_len + short_len + 2;
+	}
+
+	/* no short name set so shorten complete name */
+	if (!short_len) {
+		ptr[0] = max_len + 1;
+		ptr[1] = EIR_NAME_SHORT;
+		memcpy(ptr + 2, hdev->dev_name, max_len);
+
+		return ad_len + max_len + 2;
 	}
 
 	return ad_len;