Revert "Rollback new routing functionality (#1805)" (#1813)

This reverts commit 9f32ccd453.

util/net/listener.go

@@ -0,0 +1,21 @@
+package net
+
+import (
+	"net"
+)
+
+// ListenerConfig extends the standard net.ListenConfig with the ability to execute hooks before
+// responding via the socket and after closing. This can be used to bypass the VPN for listeners.
+type ListenerConfig struct {
+	*net.ListenConfig
+}
+
+// NewListener creates a new ListenerConfig instance.
+func NewListener() *ListenerConfig {
+	listener := &ListenerConfig{
+		ListenConfig: &net.ListenConfig{},
+	}
+	listener.init()
+
+	return listener
+}