staticd: BFD integration northbound support

Implement all BFD integration northbound callbacks and integrate BFD
with `staticd` route installation procedure.

Signed-off-by: Rafael Zalamena <rzalamena@opensourcerouting.org>

staticd/static_bfd.c

@@ -0,0 +1,219 @@
+/*
+ * Static daemon BFD integration.
+ *
+ * Copyright (C) 2020-2022 Network Device Education Foundation, Inc. ("NetDEF")
+ *                         Rafael Zalamena
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301 USA.
+ */
+
+#include <zebra.h>
+
+#include "lib/bfd.h"
+#include "lib/printfrr.h"
+#include "lib/srcdest_table.h"
+
+#include "staticd/static_routes.h"
+#include "staticd/static_zebra.h"
+
+#include "lib/openbsd-queue.h"
+
+/*
+ * Next hop BFD monitoring settings.
+ */
+static void static_next_hop_bfd_change(struct static_nexthop *sn,
+				       const struct bfd_session_status *bss)
+{
+	switch (bss->state) {
+	case BSS_UNKNOWN:
+		/* FALLTHROUGH: no known state yet. */
+	case BSS_ADMIN_DOWN:
+		/* NOTHING: we or the remote end administratively shutdown. */
+		break;
+	case BSS_DOWN:
+		/* Peer went down, remove this next hop. */
+		zlog_info("%s: next hop is down, remove it from RIB", __func__);
+		sn->path_down = true;
+		static_zebra_route_add(sn->pn, true);
+		break;
+	case BSS_UP:
+		/* Peer is back up, add this next hop. */
+		zlog_info("%s: next hop is up, add it to RIB", __func__);
+		sn->path_down = false;
+		static_zebra_route_add(sn->pn, true);
+		break;
+	}
+}
+
+static void static_next_hop_bfd_updatecb(
+	__attribute__((unused)) struct bfd_session_params *bsp,
+	const struct bfd_session_status *bss, void *arg)
+{
+	static_next_hop_bfd_change(arg, bss);
+}
+
+static inline int
+static_next_hop_type_to_family(const struct static_nexthop *sn)
+{
+	switch (sn->type) {
+	case STATIC_IPV4_GATEWAY_IFNAME:
+	case STATIC_IPV6_GATEWAY_IFNAME:
+	case STATIC_IPV4_GATEWAY:
+	case STATIC_IPV6_GATEWAY:
+		if (sn->type == STATIC_IPV4_GATEWAY ||
+		    sn->type == STATIC_IPV4_GATEWAY_IFNAME)
+			return AF_INET;
+		else
+			return AF_INET6;
+		break;
+	case STATIC_IFNAME:
+	case STATIC_BLACKHOLE:
+	default:
+		zlog_err("%s: invalid next hop type", __func__);
+		break;
+	}
+
+	return AF_UNSPEC;
+}
+
+void static_next_hop_bfd_monitor_enable(struct static_nexthop *sn,
+					const struct lyd_node *dnode)
+{
+	bool use_interface;
+	bool use_profile;
+	bool use_source;
+	bool onlink;
+	bool mhop;
+	int family;
+	struct ipaddr source;
+
+	use_interface = false;
+	use_source = yang_dnode_exists(dnode, "./source");
+	use_profile = yang_dnode_exists(dnode, "./profile");
+	onlink = yang_dnode_exists(dnode, "../onlink") &&
+		 yang_dnode_get_bool(dnode, "../onlink");
+	mhop = yang_dnode_get_bool(dnode, "./multi-hop");
+
+
+	family = static_next_hop_type_to_family(sn);
+	if (family == AF_UNSPEC)
+		return;
+
+	if (sn->type == STATIC_IPV4_GATEWAY_IFNAME ||
+	    sn->type == STATIC_IPV6_GATEWAY_IFNAME)
+		use_interface = true;
+
+	/* Reconfigure or allocate new memory. */
+	if (sn->bsp == NULL)
+		sn->bsp = bfd_sess_new(static_next_hop_bfd_updatecb, sn);
+
+	/* Configure the session. */
+	if (use_source)
+		yang_dnode_get_ip(&source, dnode, "./source");
+
+	if (onlink || mhop == false)
+		bfd_sess_set_auto_source(sn->bsp, false);
+	else
+		bfd_sess_set_auto_source(sn->bsp, !use_source);
+
+	/* Configure the session.*/
+	if (family == AF_INET)
+		bfd_sess_set_ipv4_addrs(sn->bsp,
+					use_source ? &source.ip._v4_addr : NULL,
+					&sn->addr.ipv4);
+	else if (family == AF_INET6)
+		bfd_sess_set_ipv6_addrs(sn->bsp,
+					use_source ? &source.ip._v6_addr : NULL,
+					&sn->addr.ipv6);
+
+	bfd_sess_set_interface(sn->bsp, use_interface ? sn->ifname : NULL);
+
+	bfd_sess_set_profile(sn->bsp, use_profile ? yang_dnode_get_string(
+							    dnode, "./profile")
+						  : NULL);
+
+	bfd_sess_set_hop_count(sn->bsp, (onlink || mhop == false) ? 1 : 254);
+
+	/* Install or update the session. */
+	bfd_sess_install(sn->bsp);
+
+	/* Update current path status. */
+	sn->path_down = (bfd_sess_status(sn->bsp) != BSS_UP);
+}
+
+void static_next_hop_bfd_monitor_disable(struct static_nexthop *sn)
+{
+	bfd_sess_free(&sn->bsp);
+
+	/* Reset path status. */
+	sn->path_down = false;
+}
+
+void static_next_hop_bfd_source(struct static_nexthop *sn,
+				const struct ipaddr *source)
+{
+	int family;
+
+	if (sn->bsp == NULL)
+		return;
+
+	family = static_next_hop_type_to_family(sn);
+	if (family == AF_UNSPEC)
+		return;
+
+	bfd_sess_set_auto_source(sn->bsp, false);
+	if (family == AF_INET)
+		bfd_sess_set_ipv4_addrs(sn->bsp, &source->ip._v4_addr,
+					&sn->addr.ipv4);
+	else if (family == AF_INET6)
+		bfd_sess_set_ipv6_addrs(sn->bsp, &source->ip._v6_addr,
+					&sn->addr.ipv6);
+
+	bfd_sess_install(sn->bsp);
+}
+
+void static_next_hop_bfd_auto_source(struct static_nexthop *sn)
+{
+	if (sn->bsp == NULL)
+		return;
+
+	bfd_sess_set_auto_source(sn->bsp, true);
+	bfd_sess_install(sn->bsp);
+}
+
+void static_next_hop_bfd_multi_hop(struct static_nexthop *sn, bool mhop)
+{
+	if (sn->bsp == NULL)
+		return;
+
+	bfd_sess_set_hop_count(sn->bsp, mhop ? 254 : 1);
+	bfd_sess_install(sn->bsp);
+}
+
+void static_next_hop_bfd_profile(struct static_nexthop *sn, const char *name)
+{
+	if (sn->bsp == NULL)
+		return;
+
+	bfd_sess_set_profile(sn->bsp, name);
+	bfd_sess_install(sn->bsp);
+}
+
+void static_bfd_initialize(struct zclient *zc, struct thread_master *tm)
+{
+	/* Initialize BFD integration library. */
+	bfd_protocol_integration_init(zc, tm);
+}

staticd/static_nb.c

@@ -116,6 +116,33 @@ const struct frr_yang_module_info frr_staticd_info = {
 				.destroy = routing_control_plane_protocols_control_plane_protocol_staticd_route_list_path_list_frr_nexthops_nexthop_mpls_label_stack_entry_traffic_class_destroy,
 			}
 		},
+		{
+			.xpath = "/frr-routing:routing/control-plane-protocols/control-plane-protocol/frr-staticd:staticd/route-list/path-list/frr-nexthops/nexthop/bfd-monitoring",
+			.cbs = {
+				.create = route_next_hop_bfd_create,
+				.destroy = route_next_hop_bfd_destroy,
+			}
+		},
+		{
+			.xpath = "/frr-routing:routing/control-plane-protocols/control-plane-protocol/frr-staticd:staticd/route-list/path-list/frr-nexthops/nexthop/bfd-monitoring/source",
+			.cbs = {
+				.modify = route_next_hop_bfd_source_modify,
+				.destroy = route_next_hop_bfd_source_destroy,
+			}
+		},
+		{
+			.xpath = "/frr-routing:routing/control-plane-protocols/control-plane-protocol/frr-staticd:staticd/route-list/path-list/frr-nexthops/nexthop/bfd-monitoring/multi-hop",
+			.cbs = {
+				.modify = route_next_hop_bfd_multi_hop_modify,
+			}
+		},
+		{
+			.xpath = "/frr-routing:routing/control-plane-protocols/control-plane-protocol/frr-staticd:staticd/route-list/path-list/frr-nexthops/nexthop/bfd-monitoring/profile",
+			.cbs = {
+				.modify = route_next_hop_bfd_profile_modify,
+				.destroy = route_next_hop_bfd_profile_destroy,
+			}
+		},
 		{
 			.xpath = "/frr-routing:routing/control-plane-protocols/control-plane-protocol/frr-staticd:staticd/route-list/src-list",
 			.cbs = {

staticd/static_nb.h

@@ -63,6 +63,13 @@ int routing_control_plane_protocols_control_plane_protocol_staticd_route_list_pa
 	struct nb_cb_modify_args *args);
 int routing_control_plane_protocols_control_plane_protocol_staticd_route_list_path_list_frr_nexthops_nexthop_mpls_label_stack_entry_traffic_class_destroy(
 	struct nb_cb_destroy_args *args);
+int route_next_hop_bfd_create(struct nb_cb_create_args *args);
+int route_next_hop_bfd_destroy(struct nb_cb_destroy_args *args);
+int route_next_hop_bfd_source_modify(struct nb_cb_modify_args *args);
+int route_next_hop_bfd_source_destroy(struct nb_cb_destroy_args *args);
+int route_next_hop_bfd_profile_modify(struct nb_cb_modify_args *args);
+int route_next_hop_bfd_profile_destroy(struct nb_cb_destroy_args *args);
+int route_next_hop_bfd_multi_hop_modify(struct nb_cb_modify_args *args);
 int routing_control_plane_protocols_control_plane_protocol_staticd_route_list_src_list_create(
 	struct nb_cb_create_args *args);
 int routing_control_plane_protocols_control_plane_protocol_staticd_route_list_src_list_destroy(

staticd/static_nb_config.c

@@ -748,6 +748,113 @@ int routing_control_plane_protocols_control_plane_protocol_staticd_route_list_pa
 	return NB_OK;
 }
 
+/*
+ * XPath:
+ * /frr-routing:routing/control-plane-protocols/control-plane-protocol/frr-staticd:staticd/route-list/path-list/frr-nexthops/nexthop/bfd-monitoring
+ */
+int route_next_hop_bfd_create(struct nb_cb_create_args *args)
+{
+	struct static_nexthop *sn;
+
+	if (args->event != NB_EV_APPLY)
+		return NB_OK;
+
+	sn = nb_running_get_entry(args->dnode, NULL, true);
+	static_next_hop_bfd_monitor_enable(sn, args->dnode);
+	return NB_OK;
+}
+
+int route_next_hop_bfd_destroy(struct nb_cb_destroy_args *args)
+{
+	struct static_nexthop *sn;
+
+	if (args->event != NB_EV_APPLY)
+		return NB_OK;
+
+	sn = nb_running_get_entry(args->dnode, NULL, true);
+	static_next_hop_bfd_monitor_disable(sn);
+	return NB_OK;
+}
+
+/*
+ * XPath:
+ * /frr-routing:routing/control-plane-protocols/control-plane-protocol/frr-staticd:staticd/route-list/path-list/frr-nexthops/nexthop/bfd-monitoring/source
+ */
+int route_next_hop_bfd_source_modify(struct nb_cb_modify_args *args)
+{
+	struct static_nexthop *sn;
+	struct ipaddr source;
+
+	if (args->event != NB_EV_APPLY)
+		return NB_OK;
+
+	sn = nb_running_get_entry(args->dnode, NULL, true);
+	yang_dnode_get_ip(&source, args->dnode, NULL);
+	static_next_hop_bfd_source(sn, &source);
+	return NB_OK;
+}
+
+int route_next_hop_bfd_source_destroy(struct nb_cb_destroy_args *args)
+{
+	struct static_nexthop *sn;
+
+	if (args->event != NB_EV_APPLY)
+		return NB_OK;
+
+	sn = nb_running_get_entry(args->dnode, NULL, true);
+	static_next_hop_bfd_auto_source(sn);
+	return NB_OK;
+}
+
+/*
+ * XPath:
+ * /frr-routing:routing/control-plane-protocols/control-plane-protocol/frr-staticd:staticd/route-list/path-list/frr-nexthops/nexthop/bfd-monitoring/multi-hop
+ */
+int route_next_hop_bfd_multi_hop_modify(struct nb_cb_modify_args *args)
+{
+	struct static_nexthop *sn;
+
+	if (args->event != NB_EV_APPLY)
+		return NB_OK;
+
+	sn = nb_running_get_entry(args->dnode, NULL, true);
+	static_next_hop_bfd_multi_hop(sn,
+				      yang_dnode_get_bool(args->dnode, NULL));
+
+	return NB_OK;
+}
+
+/*
+ * XPath:
+ * /frr-routing:routing/control-plane-protocols/control-plane-protocol/frr-staticd:staticd/route-list/path-list/frr-nexthops/nexthop/bfd-monitoring/profile
+ */
+int route_next_hop_bfd_profile_modify(struct nb_cb_modify_args *args)
+{
+	struct static_nexthop *sn;
+
+	if (args->event != NB_EV_APPLY)
+		return NB_OK;
+
+	sn = nb_running_get_entry(args->dnode, NULL, true);
+	static_next_hop_bfd_profile(sn,
+				    yang_dnode_get_string(args->dnode, NULL));
+
+	return NB_OK;
+}
+
+int route_next_hop_bfd_profile_destroy(struct nb_cb_destroy_args *args)
+{
+	struct static_nexthop *sn;
+
+	if (args->event != NB_EV_APPLY)
+		return NB_OK;
+
+	sn = nb_running_get_entry(args->dnode, NULL, true);
+	static_next_hop_bfd_profile(sn, NULL);
+
+	return NB_OK;
+}
+
 /*
  * XPath:
  * /frr-routing:routing/control-plane-protocols/control-plane-protocol/frr-staticd:staticd/route-list/src-list

staticd/static_routes.c

@@ -276,6 +276,8 @@ struct static_nexthop *static_add_nexthop(struct static_path *pn,
 	/* Make new static route structure. */
 	nh = XCALLOC(MTYPE_STATIC_NEXTHOP, sizeof(struct static_nexthop));
 
+	/* Copy back pointers. */
+	nh->rn = rn;
 	nh->pn = pn;
 
 	nh->type = type;
@@ -393,6 +395,8 @@ void static_delete_nexthop(struct static_nexthop *nh)
 	struct route_node *rn = pn->rn;
 
 	static_nexthop_list_del(&(pn->nexthop_list), nh);
+	/* Remove BFD session/configuration if any. */
+	bfd_sess_free(&nh->bsp);
 
 	if (nh->nh_vrf_id == VRF_UNKNOWN)
 		goto EXIT;

staticd/static_routes.h

@@ -20,6 +20,7 @@
 #ifndef __STATIC_ROUTES_H__
 #define __STATIC_ROUTES_H__
 
+#include "lib/bfd.h"
 #include "lib/mpls.h"
 #include "table.h"
 #include "memory.h"
@@ -30,6 +31,8 @@ extern "C" {
 
 DECLARE_MGROUP(STATIC);
 
+#include "staticd/static_vrf.h"
+
 /* Static route label information */
 struct static_nh_label {
 	uint8_t num_labels;
@@ -148,6 +151,13 @@ struct static_nexthop {
 
 	/* SR-TE color */
 	uint32_t color;
+
+	/** BFD integration data. */
+	struct bfd_session_params *bsp;
+	/** Back pointer for route node. */
+	struct route_node *rn;
+	/** Path connection status. */
+	bool path_down;
 };
 
 DECLARE_DLIST(static_nexthop_list, struct static_nexthop, list);
@@ -218,6 +228,22 @@ extern void zebra_stable_node_cleanup(struct route_table *table,
 extern void static_get_nh_str(struct static_nexthop *nh, char *nexthop,
 			      size_t size);
 
+/*
+ * BFD integration.
+ */
+extern void static_next_hop_bfd_source(struct static_nexthop *sn,
+				       const struct ipaddr *source);
+extern void static_next_hop_bfd_auto_source(struct static_nexthop *sn);
+extern void static_next_hop_bfd_monitor_enable(struct static_nexthop *sn,
+					       const struct lyd_node *dnode);
+extern void static_next_hop_bfd_monitor_disable(struct static_nexthop *sn);
+extern void static_next_hop_bfd_profile(struct static_nexthop *sn,
+					const char *name);
+extern void static_next_hop_bfd_multi_hop(struct static_nexthop *sn, bool mhop);
+
+/** Call this function after zebra client initialization. */
+extern void static_bfd_initialize(struct zclient *zc, struct thread_master *tm);
+
 #ifdef __cplusplus
 }
 #endif

staticd/static_zebra.c

@@ -441,6 +441,9 @@ extern void static_zebra_route_add(struct static_path *pn, bool install)
 		api_nh = &api.nexthops[nh_num];
 		if (nh->nh_vrf_id == VRF_UNKNOWN)
 			continue;
+		/* Skip next hop which peer is down. */
+		if (nh->path_down)
+			continue;
 
 		api_nh->vrf_id = nh->nh_vrf_id;
 		if (nh->onlink)
@@ -545,6 +548,7 @@ void static_zebra_init(void)
 	zclient->zebra_connected = zebra_connected;
 
 	static_nht_hash_init(static_nht_hash);
+	static_bfd_initialize(zclient, master);
 }
 
 /* static_zebra_stop used by tests/lib/test_grpc.cpp */

staticd/subdir.am

@@ -10,6 +10,7 @@ man8 += $(MANBUILD)/frr-staticd.8
 endif
 
 staticd_libstatic_a_SOURCES = \
+	staticd/static_bfd.c \
 	staticd/static_debug.c \
 	staticd/static_nht.c \
 	staticd/static_routes.c \
@@ -38,5 +39,6 @@ staticd_staticd_SOURCES = staticd/static_main.c
 staticd_staticd_LDADD = staticd/libstatic.a lib/libfrr.la $(LIBCAP)
 
 nodist_staticd_staticd_SOURCES = \
+	yang/frr-bfdd.yang.c \
 	yang/frr-staticd.yang.c \
 	# end