mgmtd: Bringup MGMTD daemon and datastore module support

Features added in this commit:
1. Bringup/shutdown new management daemon 'mgmtd' along with FRR.
2. Support for Startup, Candidate and Running DBs.
3. Lock/Unlock DS feature using pthread lock.
4. Load config from a JSON file onto candidate DS.
5. Save config to a JSON file from running/candidate DS.
6. Dump candidate or running DS contents on the terminal or a file in
   JSON/XML format.
7. Maintaining commit history (Full rollback support to be added in
   future commits).
8. Addition of debug commands.

Co-authored-by: Yash Ranjan <ranjany@vmware.com>
Co-authored-by: Abhinay Ramesh <rabhinay@vmware.com>
Co-authored-by: Ujwal P <ujwalp@vmware.com>
Signed-off-by: Pushpasis Sarkar <pushpasis@gmail.com>

1 files changed, 271 insertions, 0 deletions

diff --git a/mgmtd/mgmt_main.c b/mgmtd/mgmt_main.c
new file mode 100644
index 0000000000..050367e330
--- /dev/null
+++ b/mgmtd/mgmt_main.c
@@ -0,0 +1,271 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Main routine of mgmt.
+ *
+ * Copyright (C) 2021  Vmware, Inc.
+ *		       Pushpasis Sarkar
+ */
+
+#include <zebra.h>
+#include "lib/version.h"
+#include "routemap.h"
+#include "filter.h"
+#include "libfrr.h"
+#include "frr_pthread.h"
+#include "mgmtd/mgmt.h"
+#include "mgmtd/mgmt_ds.h"
+#include "routing_nb.h"
+
+/* mgmt options, we use GNU getopt library. */
+static const struct option longopts[] = {
+	{"skip_runas", no_argument, NULL, 'S'},
+	{"no_zebra", no_argument, NULL, 'Z'},
+	{"socket_size", required_argument, NULL, 's'},
+	{0}
+};
+
+static void mgmt_exit(int);
+static void mgmt_vrf_terminate(void);
+
+/* privileges */
+static zebra_capabilities_t _caps_p[] = {ZCAP_BIND, ZCAP_NET_RAW,
+					 ZCAP_NET_ADMIN, ZCAP_SYS_ADMIN};
+
+struct zebra_privs_t mgmt_privs = {
+#if defined(FRR_USER) && defined(FRR_GROUP)
+	.user = FRR_USER,
+	.group = FRR_GROUP,
+#endif
+#ifdef VTY_GROUP
+	.vty_group = VTY_GROUP,
+#endif
+	.caps_p = _caps_p,
+	.cap_num_p = array_size(_caps_p),
+	.cap_num_i = 0,
+};
+
+static struct frr_daemon_info mgmtd_di;
+char backup_config_file[256];
+
+/* SIGHUP handler. */
+static void sighup(void)
+{
+	zlog_info("SIGHUP received, ignoring");
+
+	return;
+
+	/*
+	 * This is turned off for the moment.  There is all
+	 * sorts of config turned off by mgmt_terminate
+	 * that is not setup properly again in mgmt_reset.
+	 * I see no easy way to do this nor do I see that
+	 * this is a desirable way to reload config
+	 * given the yang work.
+	 */
+	/* Terminate all thread. */
+	mgmt_terminate();
+
+	/*
+	 * mgmt_reset();
+	 */
+	zlog_info("MGMTD restarting!");
+
+	/*
+	 * Reload config file.
+	 * vty_read_config(NULL, mgmtd_di.config_file, config_default);
+	 */
+	/* Try to return to normal operation. */
+}
+
+/* SIGINT handler. */
+static __attribute__((__noreturn__)) void sigint(void)
+{
+	zlog_notice("Terminating on signal");
+	assert(mm->terminating == false);
+	mm->terminating = true; /* global flag that shutting down */
+
+	mgmt_terminate();
+
+	mgmt_exit(0);
+
+	exit(0);
+}
+
+/* SIGUSR1 handler. */
+static void sigusr1(void)
+{
+	zlog_rotate();
+}
+
+static struct frr_signal_t mgmt_signals[] = {
+	{
+		.signal = SIGHUP,
+		.handler = &sighup,
+	},
+	{
+		.signal = SIGUSR1,
+		.handler = &sigusr1,
+	},
+	{
+		.signal = SIGINT,
+		.handler = &sigint,
+	},
+	{
+		.signal = SIGTERM,
+		.handler = &sigint,
+	},
+};
+
+
+/*
+ * Try to free up allocations we know about so that diagnostic tools such as
+ * valgrind are able to better illuminate leaks.
+ *
+ * Zebra route removal and protocol teardown are not meant to be done here.
+ * For example, "retain_mode" may be set.
+ */
+static __attribute__((__noreturn__)) void mgmt_exit(int status)
+{
+	/* it only makes sense for this to be called on a clean exit */
+	assert(status == 0);
+
+	frr_early_fini();
+
+	/* stop pthreads (if any) */
+	frr_pthread_stop_all();
+
+	mgmt_vrf_terminate();
+
+	frr_fini();
+	exit(status);
+}
+
+static int mgmt_vrf_new(struct vrf *vrf)
+{
+	zlog_debug("VRF Created: %s(%u)", vrf->name, vrf->vrf_id);
+
+	return 0;
+}
+
+static int mgmt_vrf_delete(struct vrf *vrf)
+{
+	zlog_debug("VRF Deletion: %s(%u)", vrf->name, vrf->vrf_id);
+
+	return 0;
+}
+
+static int mgmt_vrf_enable(struct vrf *vrf)
+{
+	zlog_debug("VRF Enable: %s(%u)", vrf->name, vrf->vrf_id);
+
+	return 0;
+}
+
+static int mgmt_vrf_disable(struct vrf *vrf)
+{
+	zlog_debug("VRF Disable: %s(%u)", vrf->name, vrf->vrf_id);
+
+	/* Note: This is a callback, the VRF will be deleted by the caller. */
+	return 0;
+}
+
+static int mgmt_vrf_config_write(struct vty *vty)
+{
+	return 0;
+}
+
+static void mgmt_vrf_init(void)
+{
+	vrf_init(mgmt_vrf_new, mgmt_vrf_enable, mgmt_vrf_disable,
+		 mgmt_vrf_delete);
+	vrf_cmd_init(mgmt_vrf_config_write);
+}
+
+static void mgmt_vrf_terminate(void)
+{
+	vrf_terminate();
+}
+
+/*
+ * List of YANG modules to be loaded in the process context of
+ * MGMTd.
+ *
+ * NOTE: In future this will also include the YANG modules of
+ * all individual Backend clients.
+ */
+static const struct frr_yang_module_info *const mgmt_yang_modules[] = {
+	&frr_filter_info,  &frr_interface_info, &frr_route_map_info,
+	&frr_routing_info, &frr_vrf_info,
+};
+
+FRR_DAEMON_INFO(mgmtd, MGMTD, .vty_port = MGMTD_VTY_PORT,
+
+		.proghelp = "FRR Management Daemon.",
+
+		.signals = mgmt_signals, .n_signals = array_size(mgmt_signals),
+
+		.privs = &mgmt_privs, .yang_modules = mgmt_yang_modules,
+		.n_yang_modules = array_size(mgmt_yang_modules),
+);
+
+#define DEPRECATED_OPTIONS ""
+
+/* Main routine of mgmt. Treatment of argument and start mgmt finite
+ * state machine is handled at here.
+ */
+int main(int argc, char **argv)
+{
+	int opt;
+	int buffer_size = MGMTD_SOCKET_BUF_SIZE;
+
+	frr_preinit(&mgmtd_di, argc, argv);
+	frr_opt_add(
+		"s:" DEPRECATED_OPTIONS, longopts,
+		"  -s, --socket_size  Set MGMTD peer socket send buffer size\n");
+
+	/* Command line argument treatment. */
+	while (1) {
+		opt = frr_getopt(argc, argv, 0);
+
+		if (opt && opt < 128 && strchr(DEPRECATED_OPTIONS, opt)) {
+			fprintf(stderr,
+				"The -%c option no longer exists.\nPlease refer to the manual.\n",
+				opt);
+			continue;
+		}
+
+		if (opt == EOF)
+			break;
+
+		switch (opt) {
+		case 0:
+			break;
+		case 's':
+			buffer_size = atoi(optarg);
+			break;
+		default:
+			frr_help_exit(1);
+			break;
+		}
+	}
+
+	/* MGMTD master init. */
+	mgmt_master_init(frr_init(), buffer_size);
+
+	/* VRF Initializations. */
+	mgmt_vrf_init();
+
+	/* MGMTD related initialization.  */
+	mgmt_init();
+
+	snprintf(backup_config_file, sizeof(backup_config_file),
+		 "%s/zebra.conf", frr_sysconfdir);
+	mgmtd_di.backup_config_file = backup_config_file;
+
+	frr_config_fork();
+
+	frr_run(mm->master);
+
+	/* Not reached. */
+	return 0;
+}