Merge pull request #176 from 9seconds/fix-urls

Fix urls for missed IPs

config/urls.go

 }
 
 type IPURLs struct {
-	IPv4      URLs   `json:"ipv4"`
-	IPv6      URLs   `json:"ipv6"`
+	IPv4      *URLs  `json:"ipv4,omitempty"`
+	IPv6      *URLs  `json:"ipv6,omitempty"`
 	BotSecret string `json:"secret_for_mtproxybot"`
 }
 
 		secret = "ee" + hex.EncodeToString(C.Secret) + hex.EncodeToString([]byte(C.CloakHost))
 	}
 
-	urls.IPv4 = makeURLs(C.PublicIPv4, secret)
-	urls.IPv6 = makeURLs(C.PublicIPv6, secret)
+	if C.PublicIPv4.IP != nil {
+		urls.IPv4 = makeURLs(C.PublicIPv4, secret)
+	}
+
+	if C.PublicIPv6.IP != nil {
+		urls.IPv6 = makeURLs(C.PublicIPv6, secret)
+	}
+
 	urls.BotSecret = hex.EncodeToString(C.Secret)
 
 	return urls
 }
 
-func makeURLs(addr *net.TCPAddr, secret string) (urls URLs) {
+func makeURLs(addr *net.TCPAddr, secret string) *URLs {
+	urls := &URLs{}
+
 	values := url.Values{}
 	values.Set("server", addr.IP.String())
 	values.Set("port", strconv.Itoa(addr.Port))
 	values.Set("secret", secret)
 
-	urls.TG = makeTGURL(values)
-	urls.TMe = makeTMeURL(values)
-	urls.TGQRCode = makeQRCodeURL(urls.TG)
-	urls.TMeQRCode = makeQRCodeURL(urls.TMe)
-
-	return
+	return &URLs{
+		TG:        makeTGURL(values),
+		TMe:       makeTMeURL(values),
+		TGQRCode:  makeQRCodeURL(urls.TG),
+		TMeQRCode: makeQRCodeURL(urls.TMe),
+	}
 }
 
 func makeTGURL(values url.Values) string {