Hook to replace DOHL dialer

transport/internet/system_dialer.go

@@ -11,7 +11,10 @@ import (
 	"github.com/xtls/xray-core/features/outbound"
 )
 
-var effectiveSystemDialer SystemDialer = &DefaultSystemDialer{}
+var (
+	effectiveSystemDialer    SystemDialer = &DefaultSystemDialer{}
+	effectiveSystemDNSDialer SystemDialer = &DefaultSystemDialer{}
+)
 
 type SystemDialer interface {
 	Dial(ctx context.Context, source net.Address, destination net.Destination, sockopt *SocketConfig) (net.Conn, error)
@@ -176,6 +179,13 @@ func UseAlternativeSystemDialer(dialer SystemDialer) {
 	effectiveSystemDialer = dialer
 }
 
+func UseAlternativeSystemDNSDialer(dialer SystemDialer) {
+	if dialer == nil {
+		effectiveSystemDNSDialer = &DefaultSystemDialer{}
+	}
+	effectiveSystemDNSDialer = dialer
+}
+
 // RegisterDialerController adds a controller to the effective system dialer.
 // The controller can be used to operate on file descriptors before they are put into use.
 // It only works when effective dialer is the default dialer.