Fix the issue of ipv6 prefer after lookupAddr

libv2ray_support.go

@@ -135,18 +135,27 @@ func (d *ProtectedDialer) lookupAddr(addr string) (*resolved, error) {
 		return nil, fmt.Errorf("domain %s Failed to resolve", addr)
 	}
 
-	IPs := make([]net.IP, len(addrs))
-	for i, ia := range addrs {
-		IPs[i] = ia.IP
+	IPs := make([]net.IP, 0)
+	//ipv6 is prefer, append ipv6 then ipv4
+	//ipv6 is not prefer, append ipv4 then ipv6
+	if(d.preferIPv6) {
+		for _, ia := range addrs {
+			if(ia.IP.To4() == nil) {
+				IPs = append(IPs, ia.IP)			 
+			}
+		}		
 	}
-	// LookupIPAddr returns a slice of IPs with IPv6 addrs in front,
-	// if user perfer not IPv6, revert the result so that IPv4 addr comes first
-	if !d.preferIPv6 && len(IPs) > 1 && IPs[0].To4() == nil && IPs[len(IPs)-1].To4() != nil {
-		for i := len(IPs)/2 - 1; i >= 0; i-- {
-			opp := len(IPs) - 1 - i
-			IPs[i], IPs[opp] = IPs[opp], IPs[i]
+	for _, ia := range addrs {
+		if(ia.IP.To4() != nil) {
+			IPs = append(IPs, ia.IP)	
 		}
-		log.Printf("PrepareDomain Prefer NOT IPv6 %v\n", IPs)
+	}
+	if(!d.preferIPv6) {
+		for _, ia := range addrs {
+			if(ia.IP.To4() == nil) {
+				IPs = append(IPs, ia.IP)			 
+			}
+		}		
 	}
 
 	rs := &resolved{