Enable use of DHCPRELEASE

net-dhcp/udhcpc.py

@@ -135,6 +135,8 @@ class DHCPClient:
             if self.once:
                 self.await_ip()
             else:
+                os.kill(self.proc.pid, signal.SIGUSR2)
+                time.sleep(0.05)
                 self.proc.terminate()
 
             if self.proc.wait(timeout=timeout) != 0: