bgpd: Add '[no] flood <disable|head-end-replication>'

Add the '[no] flood <disable|head-end-replication>' command
to the l2vpn evpn afi/safi sub commands for bgp.  This command
when entered as 'flood disable' will turn off type 3 route
generation for the transmittal of the type 3 route necessary
for BUM replication on the remote VTEP.  Additionally it will
turn off the BUM handling via the new zebra command,
ZEBRA_VXLAN_FLOOD_CONTROL.

Signed-off-by: Vivek Venkatraman <vivek@cumulusnetworks.com>
Signed-off-by: Donald Sharp <sharpd@cumulusnetworks.com>

bgpd/bgp_evpn.c

@@ -2160,11 +2160,15 @@ static int update_routes_for_vni(struct bgp *bgp, struct bgpevpn *vpn)
 
 	/* Update and advertise the type-3 route (only one) followed by the
 	 * locally learnt type-2 routes (MACIP) - for this VNI.
+	 *
+	 * RT-3 only if doing head-end replication
 	 */
-	build_evpn_type3_prefix(&p, vpn->originator_ip);
-	ret = update_evpn_route(bgp, vpn, &p, 0, 0);
-	if (ret)
-		return ret;
+	if (bgp->vxlan_flood_ctrl == VXLAN_FLOOD_HEAD_END_REPL) {
+		build_evpn_type3_prefix(&p, vpn->originator_ip);
+		ret = update_evpn_route(bgp, vpn, &p, 0, 0);
+		if (ret)
+			return ret;
+	}
 
 	return update_all_type2_routes(bgp, vpn);
 }
@@ -3388,27 +3392,32 @@ static int update_advertise_vni_routes(struct bgp *bgp, struct bgpevpn *vpn)
 	/* Locate type-3 route for VNI in the per-VNI table and use its
 	 * attributes to create and advertise the type-3 route for this VNI
 	 * in the global table.
+	 *
+	 * RT-3 only if doing head-end replication
 	 */
-	build_evpn_type3_prefix(&p, vpn->originator_ip);
-	rn = bgp_node_lookup(vpn->route_table, (struct prefix *)&p);
-	if (!rn) /* unexpected */
-		return 0;
-	for (pi = rn->info; pi; pi = pi->next)
-		if (pi->peer == bgp->peer_self && pi->type == ZEBRA_ROUTE_BGP
-		    && pi->sub_type == BGP_ROUTE_STATIC)
-			break;
-	if (!pi) /* unexpected */
-		return 0;
-	attr = pi->attr;
+	if (bgp->vxlan_flood_ctrl == VXLAN_FLOOD_HEAD_END_REPL) {
+		build_evpn_type3_prefix(&p, vpn->originator_ip);
+		rn = bgp_node_lookup(vpn->route_table, (struct prefix *)&p);
+		if (!rn) /* unexpected */
+			return 0;
+		for (pi = rn->info; pi; pi = pi->next)
+			if (pi->peer == bgp->peer_self &&
+			    pi->type == ZEBRA_ROUTE_BGP
+			    && pi->sub_type == BGP_ROUTE_STATIC)
+				break;
+		if (!pi) /* unexpected */
+			return 0;
+		attr = pi->attr;
 
-	global_rn = bgp_afi_node_get(bgp->rib[afi][safi], afi, safi,
-				     (struct prefix *)&p, &vpn->prd);
-	update_evpn_route_entry(bgp, vpn, afi, safi, global_rn, attr, 1, &pi, 0,
-				mac_mobility_seqnum(attr));
+		global_rn = bgp_afi_node_get(bgp->rib[afi][safi], afi, safi,
+					     (struct prefix *)&p, &vpn->prd);
+		update_evpn_route_entry(bgp, vpn, afi, safi, global_rn, attr,
+					1, &pi, 0, mac_mobility_seqnum(attr));
 
-	/* Schedule for processing and unlock node. */
-	bgp_process(bgp, global_rn, afi, safi);
-	bgp_unlock_node(global_rn);
+		/* Schedule for processing and unlock node. */
+		bgp_process(bgp, global_rn, afi, safi);
+		bgp_unlock_node(global_rn);
+	}
 
 	/* Now, walk this VNI's route table and use the route and its attribute
 	 * to create and schedule route in global table.
@@ -3522,6 +3531,42 @@ static void withdraw_router_id_vni(struct hash_backet *backet, struct bgp *bgp)
 	delete_withdraw_vni_routes(bgp, vpn);
 }
 
+/*
+ * Create RT-3 for a VNI and schedule for processing and advertisement.
+ * This is invoked upon flooding mode changing to head-end replication.
+ */
+static void create_advertise_type3(struct hash_backet *backet, void *data)
+{
+	struct bgpevpn *vpn = backet->data;
+	struct bgp *bgp = data;
+	struct prefix_evpn p;
+
+	if (!vpn || !is_vni_live(vpn))
+		return;
+
+	build_evpn_type3_prefix(&p, vpn->originator_ip);
+	if (update_evpn_route(bgp, vpn, &p, 0, 0))
+		flog_err(EC_BGP_EVPN_ROUTE_CREATE,
+			 "Type3 route creation failure for VNI %u", vpn->vni);
+}
+
+/*
+ * Delete RT-3 for a VNI and schedule for processing and withdrawal.
+ * This is invoked upon flooding mode changing to drop BUM packets.
+ */
+static void delete_withdraw_type3(struct hash_backet *backet, void *data)
+{
+	struct bgpevpn *vpn = backet->data;
+	struct bgp *bgp = data;
+	struct prefix_evpn p;
+
+	if (!vpn || !is_vni_live(vpn))
+		return;
+
+	build_evpn_type3_prefix(&p, vpn->originator_ip);
+	delete_evpn_route(bgp, vpn, &p);
+}
+
 /*
  * Process received EVPN type-2 route (advertise or withdraw).
  */
@@ -5481,13 +5526,19 @@ int bgp_evpn_local_vni_add(struct bgp *bgp, vni_t vni,
 	/* filter routes as nexthop database has changed */
 	bgp_filter_evpn_routes_upon_martian_nh_change(bgp);
 
-	/* Create EVPN type-3 route and schedule for processing. */
-	build_evpn_type3_prefix(&p, vpn->originator_ip);
-	if (update_evpn_route(bgp, vpn, &p, 0, 0)) {
-		flog_err(EC_BGP_EVPN_ROUTE_CREATE,
-			 "%u: Type3 route creation failure for VNI %u",
-			 bgp->vrf_id, vni);
-		return -1;
+	/*
+	 * Create EVPN type-3 route and schedule for processing.
+	 *
+	 * RT-3 only if doing head-end replication
+	 */
+	if (bgp->vxlan_flood_ctrl == VXLAN_FLOOD_HEAD_END_REPL) {
+		build_evpn_type3_prefix(&p, vpn->originator_ip);
+		if (update_evpn_route(bgp, vpn, &p, 0, 0)) {
+			flog_err(EC_BGP_EVPN_ROUTE_CREATE,
+				 "%u: Type3 route creation failure for VNI %u",
+				 bgp->vrf_id, vni);
+			return -1;
+		}
 	}
 
 	/* If we have learnt and retained remote routes (VTEPs, MACs) for this
@@ -5585,6 +5636,26 @@ int bgp_evpn_local_es_add(struct bgp *bgp,
 	return 0;
 }
 
+/*
+ * Handle change in setting for BUM handling. The supported values
+ * are head-end replication and dropping all BUM packets. Any change
+ * should be registered with zebra. Also, if doing head-end replication,
+ * need to advertise local VNIs as EVPN RT-3 wheras, if BUM packets are
+ * to be dropped, the RT-3s must be withdrawn.
+ */
+void bgp_evpn_flood_control_change(struct bgp *bgp)
+{
+	zlog_info("L2VPN EVPN BUM handling is %s",
+		  bgp->vxlan_flood_ctrl == VXLAN_FLOOD_HEAD_END_REPL ?
+		  "Flooding" : "Flooding Disabled");
+
+	bgp_zebra_vxlan_flood_control(bgp, bgp->vxlan_flood_ctrl);
+	if (bgp->vxlan_flood_ctrl == VXLAN_FLOOD_HEAD_END_REPL)
+		hash_iterate(bgp->vnihash, create_advertise_type3, bgp);
+	else if (bgp->vxlan_flood_ctrl == VXLAN_FLOOD_DISABLED)
+		hash_iterate(bgp->vnihash, delete_withdraw_type3, bgp);
+}
+
 /*
  * Cleanup EVPN information on disable - Need to delete and withdraw
  * EVPN routes from peers.
@@ -5652,6 +5723,9 @@ void bgp_evpn_init(struct bgp *bgp)
 	bgp->vrf_export_rtl->del = evpn_xxport_delete_ecomm;
 	bgp->l2vnis = list_new();
 	bgp->l2vnis->cmp = (int (*)(void *, void *))vni_hash_cmp;
+
+	/* Default BUM handling is to do head-end replication. */
+	bgp->vxlan_flood_ctrl = VXLAN_FLOOD_HEAD_END_REPL;
 }
 
 void bgp_evpn_vrf_delete(struct bgp *bgp_vrf)

bgpd/bgp_evpn.h

@@ -145,6 +145,7 @@ extern int bgp_evpn_local_es_add(struct bgp *bgp, esi_t *esi,
 				 struct ipaddr *originator_ip);
 extern int bgp_evpn_local_es_del(struct bgp *bgp, esi_t *esi,
 				 struct ipaddr *originator_ip);
+extern void bgp_evpn_flood_control_change(struct bgp *bgp);
 extern void bgp_evpn_cleanup_on_disable(struct bgp *bgp);
 extern void bgp_evpn_cleanup(struct bgp *bgp);
 extern void bgp_evpn_init(struct bgp *bgp);

bgpd/bgp_evpn_vty.c

@@ -2807,6 +2807,40 @@ static void write_vni_config(struct vty *vty, struct bgpevpn *vpn)
 	}
 }
 
+#ifndef VTYSH_EXTRACT_PL
+#include "bgpd/bgp_evpn_vty_clippy.c"
+#endif
+
+DEFPY(bgp_evpn_flood_control,
+      bgp_evpn_flood_control_cmd,
+      "[no$no] flooding <disable$disable|head-end-replication$her>",
+      NO_STR
+      "Specify handling for BUM packets\n"
+      "Do not flood any BUM packets\n"
+      "Flood BUM packets using head-end replication\n")
+{
+	struct bgp *bgp = VTY_GET_CONTEXT(bgp);
+	enum vxlan_flood_control flood_ctrl;
+
+	if (!bgp)
+		return CMD_WARNING;
+
+	if (disable && !no)
+		flood_ctrl = VXLAN_FLOOD_DISABLED;
+	else if (her || no)
+		flood_ctrl = VXLAN_FLOOD_HEAD_END_REPL;
+	else
+		return CMD_WARNING;
+
+	if (bgp->vxlan_flood_ctrl == flood_ctrl)
+		return CMD_SUCCESS;
+
+	bgp->vxlan_flood_ctrl = flood_ctrl;
+	bgp_evpn_flood_control_change(bgp);
+
+	return CMD_SUCCESS;
+}
+
 DEFUN (bgp_evpn_advertise_default_gw_vni,
        bgp_evpn_advertise_default_gw_vni_cmd,
        "advertise-default-gw",
@@ -3210,6 +3244,12 @@ DEFUN(show_bgp_l2vpn_evpn_vni,
 			json_object_string_add(json, "advertiseAllVnis",
 					       is_evpn_enabled() ? "Enabled"
 								 : "Disabled");
+			json_object_string_add(
+				json, "flooding",
+				bgp_def->vxlan_flood_ctrl
+						== VXLAN_FLOOD_HEAD_END_REPL
+					? "Head-end replication"
+					: "Disabled");
 			json_object_int_add(json, "numVnis", num_vnis);
 			json_object_int_add(json, "numL2Vnis", num_l2vnis);
 			json_object_int_add(json, "numL3Vnis", num_l3vnis);
@@ -3219,6 +3259,11 @@ DEFUN(show_bgp_l2vpn_evpn_vni,
 							    : "Disabled");
 			vty_out(vty, "Advertise All VNI flag: %s\n",
 				is_evpn_enabled() ? "Enabled" : "Disabled");
+			vty_out(vty, "BUM flooding: %s\n",
+				bgp_def->vxlan_flood_ctrl
+						== VXLAN_FLOOD_HEAD_END_REPL
+					? "Head-end replication"
+					: "Disabled");
 			vty_out(vty, "Number of L2 VNIs: %u\n", num_l2vnis);
 			vty_out(vty, "Number of L3 VNIs: %u\n", num_l3vnis);
 		}
@@ -4874,6 +4919,9 @@ void bgp_config_write_evpn_info(struct vty *vty, struct bgp *bgp, afi_t afi,
 	if (bgp->advertise_gw_macip)
 		vty_out(vty, "  advertise-default-gw\n");
 
+	if (bgp->vxlan_flood_ctrl == VXLAN_FLOOD_DISABLED)
+		vty_out(vty, "  flooding disable\n");
+
 	if (CHECK_FLAG(bgp->af_flags[AFI_L2VPN][SAFI_EVPN],
 		       BGP_L2VPN_EVPN_ADVERTISE_IPV4_UNICAST)) {
 		if (bgp->adv_cmd_rmap[AFI_IP][SAFI_UNICAST].name)
@@ -4965,6 +5013,7 @@ void bgp_ethernetvpn_init(void)
 	install_element(BGP_EVPN_NODE, &no_bgp_evpn_advertise_type5_cmd);
 	install_element(BGP_EVPN_NODE, &bgp_evpn_default_originate_cmd);
 	install_element(BGP_EVPN_NODE, &no_bgp_evpn_default_originate_cmd);
+	install_element(BGP_EVPN_NODE, &bgp_evpn_flood_control_cmd);
 
 	/* test commands */
 	install_element(BGP_EVPN_NODE, &test_adv_evpn_type4_route_cmd);

bgpd/bgp_zebra.c

@@ -1931,6 +1931,29 @@ int bgp_zebra_advertise_gw_macip(struct bgp *bgp, int advertise, vni_t vni)
 	return zclient_send_message(zclient);
 }
 
+int bgp_zebra_vxlan_flood_control(struct bgp *bgp,
+				  enum vxlan_flood_control flood_ctrl)
+{
+	struct stream *s;
+
+	/* Check socket. */
+	if (!zclient || zclient->sock < 0)
+		return 0;
+
+	/* Don't try to register if Zebra doesn't know of this instance. */
+	if (!IS_BGP_INST_KNOWN_TO_ZEBRA(bgp))
+		return 0;
+
+	s = zclient->obuf;
+	stream_reset(s);
+
+	zclient_create_header(s, ZEBRA_VXLAN_FLOOD_CONTROL, bgp->vrf_id);
+	stream_putc(s, flood_ctrl);
+	stream_putw_at(s, 0, stream_get_endp(s));
+
+	return zclient_send_message(zclient);
+}
+
 int bgp_zebra_advertise_all_vni(struct bgp *bgp, int advertise)
 {
 	struct stream *s;
@@ -1951,7 +1974,7 @@ int bgp_zebra_advertise_all_vni(struct bgp *bgp, int advertise)
 	/* Also inform current BUM handling setting. This is really
 	 * relevant only when 'advertise' is set.
 	 */
-	stream_putc(s, VXLAN_FLOOD_HEAD_END_REPL);
+	stream_putc(s, bgp->vxlan_flood_ctrl);
 	stream_putw_at(s, 0, stream_get_endp(s));
 
 	return zclient_send_message(zclient);

bgpd/bgp_zebra.h

@@ -72,6 +72,8 @@ extern int bgp_zebra_advertise_subnet(struct bgp *bgp, int advertise,
 				      vni_t vni);
 extern int bgp_zebra_advertise_gw_macip(struct bgp *, int, vni_t);
 extern int bgp_zebra_advertise_all_vni(struct bgp *, int);
+extern int bgp_zebra_vxlan_flood_control(struct bgp *bgp,
+					 enum vxlan_flood_control flood_ctrl);
 
 extern int bgp_zebra_num_connects(void);
 

bgpd/bgpd.h

@@ -485,6 +485,11 @@ struct bgp {
 	/* EVPN - use RFC 8365 to auto-derive RT */
 	int advertise_autort_rfc8365;
 
+	/*
+	 * Flooding mechanism for BUM packets for VxLAN-EVPN.
+	 */
+	enum vxlan_flood_control vxlan_flood_ctrl;
+
 	/* Hash table of Import RTs to EVIs */
 	struct hash *import_rt_hash;
 

bgpd/subdir.am

@@ -208,6 +208,8 @@ bgpd_bgpd_rpki_la_CFLAGS = $(WERROR) $(RTRLIB_CFLAGS)
 bgpd_bgpd_rpki_la_LDFLAGS = -avoid-version -module -shared -export-dynamic
 bgpd_bgpd_rpki_la_LIBADD = $(RTRLIB_LIBS)
 
+bgpd/bgp_evpn_vty_clippy.c: $(CLIPPY_DEPS)
+bgpd/bgp_evpn_vty.$(OBJEXT): bgpd/bgp_evpn_vty_clippy.c
 bgpd/bgp_vty_clippy.c: $(CLIPPY_DEPS)
 bgpd/bgp_vty.$(OBJEXT): bgpd/bgp_vty_clippy.c
 bgpd/bgp_route_clippy.c: $(CLIPPY_DEPS)