netlink: clean up sockets, close files

Sockets are handled for most usage paths, except for
shutdown. Handle those at shutdown.

Signed-off-by: Paul Donald <newtwen+github@gmail.com>

Author: systemcrash

src/netlink.c

@@ -1140,3 +1140,27 @@ void netlink_dump_addr_table(const bool v6)
 
 	nlmsg_free(msg);
 }
+
+/* Shut down and free netlink sockets/registration. Safe to call multiple times. */
+void netlink_shutdown(void)
+{
+	/* Deregister event and free the event socket */
+	if (rtnl_event.sock) {
+		odhcpd_deregister(&rtnl_event.ev);
+
+		if (rtnl_event.ev.uloop.fd >= 0) {
+			uloop_fd_delete(&rtnl_event.ev.uloop);
+			close(rtnl_event.ev.uloop.fd);
+			rtnl_event.ev.uloop.fd = -1;
+		}
+
+		nl_socket_free(rtnl_event.sock);
+		rtnl_event.sock = NULL;
+	}
+
+	/* Free the primary rtnl socket */
+	if (rtnl_socket) {
+		nl_socket_free(rtnl_socket);
+		rtnl_socket = NULL;
+	}
+}

src/odhcpd.c

@@ -187,6 +187,8 @@ int main(int argc, char **argv)
 	if (dhcpv4_init())
 		return 4;
 #endif
+	atexit(router_shutdown);
+	atexit(netlink_shutdown);
 
 	return odhcpd_run();
 }

src/odhcpd.h

@@ -92,6 +92,10 @@ struct nl_sock;
 extern struct config config;
 extern struct sys_conf sys_conf;
 
+/* Shutdown helpers */
+void netlink_shutdown(void);
+void router_shutdown(void);
+
 void __iflog(int lvl, const char *fmt, ...);
 #define debug(fmt, ...) __iflog(LOG_DEBUG, fmt __VA_OPT__(, ) __VA_ARGS__)
 #define info(fmt, ...) __iflog(LOG_INFO, fmt __VA_OPT__(, ) __VA_ARGS__)

src/router.c

@@ -61,12 +61,19 @@ int router_init(void)
 	}
 
 out:
-	if (ret < 0 && fp_route) {
+	if (ret < 0)
+		router_shutdown();
+
+	return ret;
+}
+
+/* Shutdown helper: close fp_route if open. Safe to call multiple times. */
+void router_shutdown(void)
+{
+	if (fp_route) {
 		fclose(fp_route);
 		fp_route = NULL;
 	}
-
-	return ret;
 }