Fix: unexpected proxy dial behavior on mapping mode

constant/metadata.go

@@ -71,6 +71,7 @@ type Metadata struct {
 	DstPort  string  `json:"destinationPort"`
 	AddrType int     `json:"-"`
 	Host     string  `json:"host"`
+	DNSMode  DNSMode `json:"dnsMode"`
 }
 
 func (m *Metadata) RemoteAddress() string {
@@ -85,6 +86,23 @@ func (m *Metadata) Resolved() bool {
 	return m.DstIP != nil
 }
 
+// Pure is used to solve unexpected behavior
+// when dialing proxy connection in DNSMapping mode.
+func (m *Metadata) Pure() *Metadata {
+	if m.DNSMode == DNSMapping && m.DstIP != nil {
+		copy := *m
+		copy.Host = ""
+		if copy.DstIP.To4() != nil {
+			copy.AddrType = AtypIPv4
+		} else {
+			copy.AddrType = AtypIPv6
+		}
+		return &copy
+	}
+
+	return m
+}
+
 func (m *Metadata) UDPAddr() *net.UDPAddr {
 	if m.NetWork != UDP || m.DstIP == nil {
 		return nil