network: on freebsd using SO_REUSEPORT_LB for a better distribution.

SO_REUSEPORT on FreeBSD acts differently as the underlying semantic
is different (as it predates Linux) since it s more for UDP/multicasts.
The SO_REUSEPORT_LB flag, however, uses load balancing for group
of address:port combinations which is how Linux is implemented.

Co-authored-by: Jakub Zelenka <bukka@php.net>

Author: devnexen

main/network.c

@@ -497,7 +497,13 @@ php_socket_t php_network_bind_socket_to_local_addr(const char *host, unsigned po
 		/* attempt to bind */
 
 		if (sockopts & STREAM_SOCKOP_SO_REUSEADDR) {
+#ifdef SO_REUSEPORT_LB
+			/* Historically, SO_REUSEPORT on FreeBSD predates Linux version, however does not
+			 * involve load balancing grouping thus SO_REUSEPORT_LB is the genuine equivalent.*/
+			setsockopt(sock, SOL_SOCKET, SO_REUSEPORT_LB, (char*)&sockoptval, sizeof(sockoptval));
+#else
 			setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (char*)&sockoptval, sizeof(sockoptval));
+#endif
 		}
 #ifdef PHP_WIN32
 		else {