Add missed package

util/netutil.go

@@ -0,0 +1,56 @@
+package util
+
+import (
+	"log"
+	"net"
+	"strings"
+
+	"github.com/gorilla/websocket"
+)
+
+// GetRemoteAddress returns public address of websocket connection
+func GetRemoteAddress(conn *websocket.Conn) string {
+	var remoteAddr string
+	log.Println("Address :", conn.RemoteAddr().String())
+	if parts := strings.Split(conn.RemoteAddr().String(), ":"); len(parts) == 2 {
+		remoteAddr = parts[0]
+	}
+	if remoteAddr == "" {
+		return "localhost"
+	}
+
+	return remoteAddr
+}
+
+// IsPublicIP checks if address is public address
+func IsPublicIP(address string) bool {
+	ip := net.ParseIP(address)
+	if ip.IsLoopback() || ip.IsLinkLocalMulticast() || ip.IsLinkLocalUnicast() {
+		return false
+	}
+	if ip4 := ip.To4(); ip4 != nil {
+		switch {
+		case ip4[0] == 10:
+			return false
+		case ip4[0] == 172 && ip4[1] >= 16 && ip4[1] <= 31:
+			return false
+		case ip4[0] == 192 && ip4[1] == 168:
+			return false
+		default:
+			return true
+		}
+	}
+	return false
+}
+
+// GetHostPublicIP to get the public ip address. Only work if not behind NAT
+func GetHostPublicIP() string {
+	conn, err := net.Dial("udp", "8.8.8.8:80")
+	if err != nil {
+		return ""
+	}
+	defer conn.Close()
+	localAddr := conn.LocalAddr().String()
+	idx := strings.LastIndex(localAddr, ":")
+	return localAddr[0:idx]
+}