Add SO_REUSEPORT option for SSDP

fixes #541

miniupnpd/Changelog.txt

@@ -1,5 +1,8 @@
 $Id: Changelog.txt,v 1.475 2021/05/11 21:57:18 nanard Exp $
 
+2021/04/22:
+  Add SO_REUSEPORT option for SSDP receive sockets
+
 2021/03/31:
   GetExternalIPAddress returns empty string when the External IP address can
     not be retrieved.

miniupnpd/minissdp.c

@@ -2,7 +2,7 @@
 /* vim: tabstop=4 shiftwidth=4 noexpandtab
  * MiniUPnP project
  * http://miniupnp.free.fr/ or https://miniupnp.tuxfamily.org/
- * (c) 2006-2020 Thomas Bernard
+ * (c) 2006-2021 Thomas Bernard
  * This software is subject to the conditions detailed
  * in the LICENCE file provided within the distribution */
 
@@ -197,6 +197,10 @@ OpenAndConfSSDPReceiveSocket(int ipv6)
 	{
 		syslog(LOG_WARNING, "setsockopt(udp, SO_REUSEADDR): %m");
 	}
+	if (setsockopt(s, SOL_SOCKET, SO_REUSEPORT, &on, sizeof(on)) < 0)
+	{
+		syslog(LOG_WARNING, "setsockopt(udp, SO_REUSEPORT): %m");
+	}
 #ifdef IP_RECVIF
 	/* BSD */
 	if(!ipv6) {