added --freebind option (Linux only)

socket.c

@@ -500,6 +500,17 @@ int bind_to_tcp(char *socket_name, int listen_queue, char *tcp_port) {
 		uwsgi_nuclear_blast();
 	}
 
+#ifdef __linux__
+#ifdef IP_FREEBIND
+	if (uwsgi.freebind) {
+		if (setsockopt(serverfd, SOL_IP, IP_FREEBIND, (const void *) &uwsgi.freebind, sizeof(int)) < 0) {
+			uwsgi_error("setsockopt()");
+			uwsgi_nuclear_blast();
+		}
+	}
+#endif
+#endif
+
 	if (uwsgi.reuse_port) {
 #ifdef SO_REUSEPORT
 		if (setsockopt(serverfd, SOL_SOCKET, SO_REUSEPORT, (const void *) &uwsgi.reuse_port, sizeof(int)) < 0) {

uwsgi.c

@@ -57,6 +57,9 @@ static struct option long_base_options[] = {
 	{"abstract-socket", no_argument, 0, 'a'},
 	{"chmod-socket", optional_argument, 0, 'C'},
 	{"chown-socket", required_argument, 0, LONG_ARGS_CHOWN_SOCKET},
+#ifdef __linux__
+	{"freebind", no_argument, &uwsgi.freebind, 1},
+#endif
 	{"map-socket", required_argument, 0, LONG_ARGS_MAP_SOCKET},
 	{"chmod", optional_argument, 0, 'C'},
 #ifdef UWSGI_THREADING

uwsgi.h

@@ -1095,6 +1095,10 @@ struct uwsgi_server {
 	struct timeval start_tv;
 
 	int abstract_socket;
+#ifdef __linux__
+	int freebind;
+#endif
+
 	int chmod_socket;
 	char *chown_socket;
 	mode_t chmod_socket_value;