1 files changed, 232 insertions, 0 deletions
diff --git a/isisd/isis_bfd.c b/isisd/isis_bfd.c
new file mode 100644
index 0000000..1877c83
--- /dev/null
+++ b/isisd/isis_bfd.c
@@ -0,0 +1,232 @@
+/*
+ * IS-IS Rout(e)ing protocol - BFD support
+ * Copyright (C) 2018 Christian Franke
+ *
+ * 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; see the file COPYING; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+#include <zebra.h>
+
+#include "zclient.h"
+#include "nexthop.h"
+#include "bfd.h"
+#include "lib_errors.h"
+
+#include "isisd/isis_bfd.h"
+#include "isisd/isis_zebra.h"
+#include "isisd/isis_common.h"
+#include "isisd/isis_constants.h"
+#include "isisd/isis_adjacency.h"
+#include "isisd/isis_circuit.h"
+#include "isisd/isisd.h"
+#include "isisd/fabricd.h"
+
+DEFINE_MTYPE_STATIC(ISISD, BFD_SESSION, "ISIS BFD Session");
+
+static void adj_bfd_cb(struct bfd_session_params *bsp,
+		       const struct bfd_session_status *bss, void *arg)
+{
+	struct isis_adjacency *adj = arg;
+
+	if (IS_DEBUG_BFD)
+		zlog_debug(
+			"ISIS-BFD: BFD changed status for adjacency %s old %s new %s",
+			isis_adj_name(adj),
+			bfd_get_status_str(bss->previous_state),
+			bfd_get_status_str(bss->state));
+
+	if (bss->state == BFD_STATUS_DOWN
+	    && bss->previous_state == BFD_STATUS_UP) {
+		adj->circuit->area->bfd_signalled_down = true;
+		isis_adj_state_change(&adj, ISIS_ADJ_DOWN,
+				      "bfd session went down");
+	}
+}
+
+static void bfd_handle_adj_down(struct isis_adjacency *adj)
+{
+	bfd_sess_free(&adj->bfd_session);
+}
+
+static void bfd_handle_adj_up(struct isis_adjacency *adj)
+{
+	struct isis_circuit *circuit = adj->circuit;
+	int family;
+	union g_addr dst_ip;
+	union g_addr src_ip;
+	struct list *local_ips;
+	struct prefix *local_ip;
+
+	if (!circuit->bfd_config.enabled) {
+		if (IS_DEBUG_BFD)
+			zlog_debug(
+				"ISIS-BFD: skipping BFD initialization on adjacency with %s because BFD is not enabled for the circuit",
+				isis_adj_name(adj));
+		goto out;
+	}
+
+	/* If IS-IS IPv6 is configured wait for IPv6 address to be programmed
+	 * before starting up BFD
+	 */
+	if (circuit->ipv6_router
+	    && (listcount(circuit->ipv6_link) == 0
+		|| adj->ll_ipv6_count == 0)) {
+		if (IS_DEBUG_BFD)
+			zlog_debug(
+				"ISIS-BFD: skipping BFD initialization on adjacency with %s because IPv6 is enabled but not ready",
+				isis_adj_name(adj));
+		return;
+	}
+
+	/*
+	 * If IS-IS is enabled for both IPv4 and IPv6 on the circuit, prefer
+	 * creating a BFD session over IPv6.
+	 */
+	if (circuit->ipv6_router && adj->ll_ipv6_count) {
+		family = AF_INET6;
+		dst_ip.ipv6 = adj->ll_ipv6_addrs[0];
+		local_ips = circuit->ipv6_link;
+		if (list_isempty(local_ips)) {
+			if (IS_DEBUG_BFD)
+				zlog_debug(
+					"ISIS-BFD: skipping BFD initialization: IPv6 enabled and no local IPv6 addresses");
+			goto out;
+		}
+		local_ip = listgetdata(listhead(local_ips));
+		src_ip.ipv6 = local_ip->u.prefix6;
+	} else if (circuit->ip_router && adj->ipv4_address_count) {
+		family = AF_INET;
+		dst_ip.ipv4 = adj->ipv4_addresses[0];
+		local_ips = fabricd_ip_addrs(adj->circuit);
+		if (!local_ips || list_isempty(local_ips)) {
+			if (IS_DEBUG_BFD)
+				zlog_debug(
+					"ISIS-BFD: skipping BFD initialization: IPv4 enabled and no local IPv4 addresses");
+			goto out;
+		}
+		local_ip = listgetdata(listhead(local_ips));
+		src_ip.ipv4 = local_ip->u.prefix4;
+	} else
+		goto out;
+
+	if (adj->bfd_session == NULL)
+		adj->bfd_session = bfd_sess_new(adj_bfd_cb, adj);
+
+	bfd_sess_set_timers(adj->bfd_session, BFD_DEF_DETECT_MULT,
+			    BFD_DEF_MIN_RX, BFD_DEF_MIN_TX);
+	if (family == AF_INET)
+		bfd_sess_set_ipv4_addrs(adj->bfd_session, &src_ip.ipv4,
+					&dst_ip.ipv4);
+	else
+		bfd_sess_set_ipv6_addrs(adj->bfd_session, &src_ip.ipv6,
+					&dst_ip.ipv6);
+	bfd_sess_set_interface(adj->bfd_session, adj->circuit->interface->name);
+	bfd_sess_set_vrf(adj->bfd_session,
+			 adj->circuit->interface->vrf->vrf_id);
+	bfd_sess_set_profile(adj->bfd_session, circuit->bfd_config.profile);
+	bfd_sess_install(adj->bfd_session);
+	return;
+out:
+	bfd_handle_adj_down(adj);
+}
+
+static int bfd_handle_adj_state_change(struct isis_adjacency *adj)
+{
+	if (adj->adj_state == ISIS_ADJ_UP)
+		bfd_handle_adj_up(adj);
+	else
+		bfd_handle_adj_down(adj);
+	return 0;
+}
+
+static void bfd_adj_cmd(struct isis_adjacency *adj)
+{
+	if (adj->adj_state == ISIS_ADJ_UP && adj->circuit->bfd_config.enabled)
+		bfd_handle_adj_up(adj);
+	else
+		bfd_handle_adj_down(adj);
+}
+
+void isis_bfd_circuit_cmd(struct isis_circuit *circuit)
+{
+	switch (circuit->circ_type) {
+	case CIRCUIT_T_BROADCAST:
+		for (int level = ISIS_LEVEL1; level <= ISIS_LEVEL2; level++) {
+			struct list *adjdb = circuit->u.bc.adjdb[level - 1];
+
+			struct listnode *node;
+			struct isis_adjacency *adj;
+
+			if (!adjdb)
+				continue;
+			for (ALL_LIST_ELEMENTS_RO(adjdb, node, adj))
+				bfd_adj_cmd(adj);
+		}
+		break;
+	case CIRCUIT_T_P2P:
+		if (circuit->u.p2p.neighbor)
+			bfd_adj_cmd(circuit->u.p2p.neighbor);
+		break;
+	default:
+		break;
+	}
+}
+
+static int bfd_handle_adj_ip_enabled(struct isis_adjacency *adj, int family,
+				     bool global)
+{
+
+	if (family != AF_INET6 || global)
+		return 0;
+
+	if (adj->bfd_session)
+		return 0;
+
+	if (adj->adj_state != ISIS_ADJ_UP)
+		return 0;
+
+	bfd_handle_adj_up(adj);
+
+	return 0;
+}
+
+static int bfd_handle_circuit_add_addr(struct isis_circuit *circuit)
+{
+	struct isis_adjacency *adj;
+	struct listnode *node;
+
+	if (circuit->area == NULL)
+		return 0;
+
+	for (ALL_LIST_ELEMENTS_RO(circuit->area->adjacency_list, node, adj)) {
+		if (adj->bfd_session)
+			continue;
+
+		if (adj->adj_state != ISIS_ADJ_UP)
+			continue;
+
+		bfd_handle_adj_up(adj);
+	}
+
+	return 0;
+}
+
+void isis_bfd_init(struct thread_master *tm)
+{
+	bfd_protocol_integration_init(zclient, tm);
+
+	hook_register(isis_adj_state_change_hook, bfd_handle_adj_state_change);
+	hook_register(isis_adj_ip_enabled_hook, bfd_handle_adj_ip_enabled);
+	hook_register(isis_circuit_add_addr_hook, bfd_handle_circuit_add_addr);
+}