1 files changed, 99 insertions, 0 deletions
diff --git a/bgpd/bgp_nhg.c b/bgpd/bgp_nhg.c
new file mode 100644
index 0000000..bf0ba77
--- /dev/null
+++ b/bgpd/bgp_nhg.c
@@ -0,0 +1,99 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* BGP Nexthop Group Support
+ * Copyright (C) 2023 NVIDIA Corporation
+ * Copyright (C) 2023 6WIND
+ */
+
+#include <zebra.h>
+
+#include <bgpd/bgpd.h>
+#include <bgpd/bgp_debug.h>
+#include <bgpd/bgp_nhg.h>
+
+
+/****************************************************************************
+ * L3 NHGs are used for fast failover of nexthops in the dplane. These are
+ * the APIs for allocating L3 NHG ids. Management of the L3 NHG itself is
+ * left to the application using it.
+ * PS: Currently EVPN host routes is the only app using L3 NHG for fast
+ * failover of remote ES links.
+ ***************************************************************************/
+static bitfield_t bgp_nh_id_bitmap;
+static uint32_t bgp_nhg_start;
+
+/* XXX - currently we do nothing on the callbacks */
+static void bgp_nhg_add_cb(const char *name)
+{
+}
+
+static void bgp_nhg_modify_cb(const struct nexthop_group_cmd *nhgc)
+{
+}
+
+static void bgp_nhg_add_nexthop_cb(const struct nexthop_group_cmd *nhgc,
+				   const struct nexthop *nhop)
+{
+}
+
+static void bgp_nhg_del_nexthop_cb(const struct nexthop_group_cmd *nhgc,
+				   const struct nexthop *nhop)
+{
+}
+
+static void bgp_nhg_del_cb(const char *name)
+{
+}
+
+static void bgp_nhg_zebra_init(void)
+{
+	static bool bgp_nhg_zebra_inited;
+
+	if (bgp_nhg_zebra_inited)
+		return;
+
+	bgp_nhg_zebra_inited = true;
+	bgp_nhg_start = zclient_get_nhg_start(ZEBRA_ROUTE_BGP);
+	nexthop_group_init(bgp_nhg_add_cb, bgp_nhg_modify_cb,
+			   bgp_nhg_add_nexthop_cb, bgp_nhg_del_nexthop_cb,
+			   bgp_nhg_del_cb);
+}
+
+void bgp_nhg_init(void)
+{
+	uint32_t id_max;
+
+	id_max = MIN(ZEBRA_NHG_PROTO_SPACING - 1, 16 * 1024);
+	bf_init(bgp_nh_id_bitmap, id_max);
+	bf_assign_zero_index(bgp_nh_id_bitmap);
+
+	if (BGP_DEBUG(nht, NHT) || BGP_DEBUG(evpn_mh, EVPN_MH_ES))
+		zlog_debug("bgp nhg range %u - %u", bgp_nhg_start + 1,
+			   bgp_nhg_start + id_max);
+}
+
+void bgp_nhg_finish(void)
+{
+	bf_free(bgp_nh_id_bitmap);
+}
+
+uint32_t bgp_nhg_id_alloc(void)
+{
+	uint32_t nhg_id = 0;
+
+	bgp_nhg_zebra_init();
+	bf_assign_index(bgp_nh_id_bitmap, nhg_id);
+	if (nhg_id)
+		nhg_id += bgp_nhg_start;
+
+	return nhg_id;
+}
+
+void bgp_nhg_id_free(uint32_t nhg_id)
+{
+	if (!nhg_id || (nhg_id <= bgp_nhg_start))
+		return;
+
+	nhg_id -= bgp_nhg_start;
+
+	bf_release_index(bgp_nh_id_bitmap, nhg_id);
+}