Move main() out of clatd.c.
This allows us to unit test methods that are in clatd.c.
Also simplify the build file, adding a defaults stanza and
grouping files in a filegroup so that both the code and the unit
test have the same source files.
Test: atest clatd_test
Test: builds, boots, 464xlat works
Change-Id: I544c3ee846abd3e38b80a2d9a4db5497fd9beb0c
diff --git a/main.c b/main.c
new file mode 100644
index 0000000..e717498
--- /dev/null
+++ b/main.c
@@ -0,0 +1,144 @@
+/*
+ * Copyright 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * main.c - main function
+ */
+
+#include <errno.h>
+#include <netinet/in.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/capability.h>
+#include <unistd.h>
+
+#include "resolv_netid.h"
+
+#include "clatd.h"
+#include "common.h"
+#include "config.h"
+#include "logging.h"
+#include "setif.h"
+#include "tun.h"
+
+#define DEVICEPREFIX "v4-"
+
+/* function: print_help
+ * in case the user is running this on the command line
+ */
+void print_help() {
+ printf("android-clat arguments:\n");
+ printf("-i [uplink interface]\n");
+ printf("-p [plat prefix]\n");
+ printf("-n [NetId]\n");
+ printf("-m [socket mark]\n");
+}
+
+/* function: main
+ * allocate and setup the tun device, then run the event loop
+ */
+int main(int argc, char **argv) {
+ struct tun_data tunnel;
+ int opt;
+ char *uplink_interface = NULL, *plat_prefix = NULL, *net_id_str = NULL, *mark_str = NULL;
+ unsigned net_id = NETID_UNSET;
+ uint32_t mark = MARK_UNSET;
+ unsigned len;
+
+ while ((opt = getopt(argc, argv, "i:p:n:m:h")) != -1) {
+ switch (opt) {
+ case 'i':
+ uplink_interface = optarg;
+ break;
+ case 'p':
+ plat_prefix = optarg;
+ break;
+ case 'n':
+ net_id_str = optarg;
+ break;
+ case 'm':
+ mark_str = optarg;
+ break;
+ case 'h':
+ print_help();
+ exit(0);
+ default:
+ logmsg(ANDROID_LOG_FATAL, "Unknown option -%c. Exiting.", (char)optopt);
+ exit(1);
+ }
+ }
+
+ if (uplink_interface == NULL) {
+ logmsg(ANDROID_LOG_FATAL, "clatd called without an interface");
+ exit(1);
+ }
+
+ if (net_id_str != NULL && !parse_unsigned(net_id_str, &net_id)) {
+ logmsg(ANDROID_LOG_FATAL, "invalid NetID %s", net_id_str);
+ exit(1);
+ }
+
+ if (mark_str != NULL && !parse_unsigned(mark_str, &mark)) {
+ logmsg(ANDROID_LOG_FATAL, "invalid mark %s", mark_str);
+ exit(1);
+ }
+
+ len = snprintf(tunnel.device4, sizeof(tunnel.device4), "%s%s", DEVICEPREFIX, uplink_interface);
+ if (len >= sizeof(tunnel.device4)) {
+ logmsg(ANDROID_LOG_FATAL, "interface name too long '%s'", tunnel.device4);
+ exit(1);
+ }
+
+ logmsg(ANDROID_LOG_INFO, "Starting clat version %s on %s netid=%s mark=%s", CLATD_VERSION,
+ uplink_interface, net_id_str ? net_id_str : "(none)", mark_str ? mark_str : "(none)");
+
+ // run under a regular user but keep needed capabilities
+ drop_root_but_keep_caps();
+
+ // open our raw sockets before dropping privs
+ open_sockets(&tunnel, mark);
+
+ // keeps only admin capability
+ set_capability(1 << CAP_NET_ADMIN);
+
+ // we can create tun devices as non-root because we're in the VPN group.
+ tunnel.fd4 = tun_open();
+ if (tunnel.fd4 < 0) {
+ logmsg(ANDROID_LOG_FATAL, "tun_open4 failed: %s", strerror(errno));
+ exit(1);
+ }
+
+ // When run from netd, the environment variable ANDROID_DNS_MODE is set to
+ // "local", but that only works for the netd process itself. Removing the
+ // following line causes XLAT failure in permissive mode.
+ unsetenv("ANDROID_DNS_MODE");
+
+ configure_interface(uplink_interface, plat_prefix, &tunnel, net_id);
+
+ update_clat_ipv6_address(&tunnel, uplink_interface);
+
+ // Loop until someone sends us a signal or brings down the tun interface.
+ if (signal(SIGTERM, stop_loop) == SIG_ERR) {
+ logmsg(ANDROID_LOG_FATAL, "sigterm handler failed: %s", strerror(errno));
+ exit(1);
+ }
+
+ event_loop(&tunnel);
+
+ logmsg(ANDROID_LOG_INFO, "Shutting down clat on %s", uplink_interface);
+ del_anycast_address(tunnel.write_fd6, &Global_Clatd_Config.ipv6_local_subnet);
+
+ return 0;
+}