zebra: add knob to accept lower seq in evpn

Add a knob to accept lower seq number in evpn updates
from BGP in Zebra.

Note: Knob is enabled by default

Signed-off-by: Stephen Worley <sworley@nvidia.com>

zebra/zebra_evpn_mac.c

@@ -1597,6 +1597,7 @@ static inline bool zebra_evpn_mac_is_bgp_seq_ok(struct zebra_evpn *zevpn,
 						bool sync)
 {
 	char ipbuf[INET6_ADDRSTRLEN];
+	char mac_buf[MAC_BUF_SIZE];
 	uint32_t tmp_seq;
 	const char *n_type;
 
@@ -1611,19 +1612,14 @@ static inline bool zebra_evpn_mac_is_bgp_seq_ok(struct zebra_evpn *zevpn,
 	if (seq < tmp_seq) {
 		/* if the mac was never advertised to bgp we must accept
 		 * whatever sequence number bgp sends
-		 * XXX - check with Vivek
 		 */
-		if (CHECK_FLAG(mac->flags, ZEBRA_MAC_LOCAL)
-		    && !zebra_evpn_mac_is_ready_for_bgp(mac->flags)) {
-			if (IS_ZEBRA_DEBUG_EVPN_MH_MAC
-			    || IS_ZEBRA_DEBUG_VXLAN) {
-				char mac_buf[MAC_BUF_SIZE];
-
+		if (zebra_vxlan_accept_bgp_seq()) {
+			if (IS_ZEBRA_DEBUG_EVPN_MH_MAC ||
+			    IS_ZEBRA_DEBUG_VXLAN) {
 				zlog_debug(
 					"%s-macip accept vni %u %s-mac %pEA%s%s lower seq %u f %s",
 					sync ? "sync" : "rem", zevpn->vni,
-					n_type,
-					&mac->macaddr,
+					n_type, &mac->macaddr,
 					ipa_len ? " IP " : "",
 					ipa_len ? ipaddr2str(ipaddr, ipbuf,
 							     sizeof(ipbuf))
@@ -1637,8 +1633,6 @@ static inline bool zebra_evpn_mac_is_bgp_seq_ok(struct zebra_evpn *zevpn,
 		}
 
 		if (IS_ZEBRA_DEBUG_EVPN_MH_MAC || IS_ZEBRA_DEBUG_VXLAN) {
-			char mac_buf[MAC_BUF_SIZE];
-
 			zlog_debug(
 				"%s-macip ignore vni %u %s-mac %pEA%s%s as existing has higher seq %u f %s",
 				sync ? "sync" : "rem", zevpn->vni, n_type,
@@ -1651,6 +1645,7 @@ static inline bool zebra_evpn_mac_is_bgp_seq_ok(struct zebra_evpn *zevpn,
 				zebra_evpn_zebra_mac_flag_dump(
 					mac, mac_buf, sizeof(mac_buf)));
 		}
+
 		return false;
 	}
 

zebra/zebra_evpn_neigh.c

@@ -513,10 +513,8 @@ bool zebra_evpn_neigh_is_bgp_seq_ok(struct zebra_evpn *zevpn,
 	if (seq < tmp_seq) {
 		/* if the neigh was never advertised to bgp we must accept
 		 * whatever sequence number bgp sends
-		 * XXX - check with Vivek
 		 */
-		if (CHECK_FLAG(n->flags, ZEBRA_NEIGH_LOCAL)
-		    && !zebra_evpn_neigh_is_ready_for_bgp(n)) {
+		if (zebra_vxlan_accept_bgp_seq()) {
 			if (IS_ZEBRA_DEBUG_EVPN_MH_NEIGH
 			    || IS_ZEBRA_DEBUG_VXLAN)
 				zlog_debug(

zebra/zebra_vty.c

@@ -3740,6 +3740,27 @@ DEFPY (clear_evpn_dup_addr,
 	return ret;
 }
 
+DEFPY_HIDDEN (evpn_accept_bgp_seq,
+              evpn_accept_bgp_seq_cmd,
+              "evpn accept-bgp-seq",
+              "EVPN\n"
+	      "Accept all sequence numbers from BGP\n")
+{
+	zebra_vxlan_set_accept_bgp_seq(true);
+	return CMD_SUCCESS;
+}
+
+DEFPY_HIDDEN (no_evpn_accept_bgp_seq,
+              no_evpn_accept_bgp_seq_cmd,
+              "no evpn accept-bgp-seq",
+              NO_STR
+              "EVPN\n"
+	      "Accept all sequence numbers from BGP\n")
+{
+	zebra_vxlan_set_accept_bgp_seq(false);
+	return CMD_SUCCESS;
+}
+
 /* Static ip route configuration write function. */
 static int zebra_ip_config(struct vty *vty)
 {
@@ -3945,6 +3966,9 @@ static int config_write_protocol(struct vty *vty)
 
 	zebra_pbr_config_write(vty);
 
+	if (!zebra_vxlan_accept_bgp_seq())
+		vty_out(vty, "no evpn accept-bgp-seq\n");
+
 	/* Include nexthop-group config */
 	if (!zebra_nhg_kernel_nexthops_enabled())
 		vty_out(vty, "no zebra nexthop kernel enable\n");
@@ -4582,6 +4606,8 @@ void zebra_vty_init(void)
 	install_element(VIEW_NODE, &show_evpn_neigh_vni_dad_cmd);
 	install_element(VIEW_NODE, &show_evpn_neigh_vni_all_dad_cmd);
 	install_element(ENABLE_NODE, &clear_evpn_dup_addr_cmd);
+	install_element(CONFIG_NODE, &evpn_accept_bgp_seq_cmd);
+	install_element(CONFIG_NODE, &no_evpn_accept_bgp_seq_cmd);
 
 	install_element(VIEW_NODE, &show_neigh_cmd);
 

zebra/zebra_vxlan.c

@@ -69,6 +69,9 @@ DEFINE_HOOK(zebra_rmac_update,
 	     const char *reason),
 	    (rmac, zl3vni, delete, reason));
 
+/* config knobs */
+static bool accept_bgp_seq = true;
+
 /* static function declarations */
 static void zevpn_print_neigh_hash_all_evpn(struct hash_bucket *bucket,
 					    void **args);
@@ -6284,6 +6287,17 @@ extern void zebra_vxlan_handle_result(struct zebra_dplane_ctx *ctx)
 	return;
 }
 
+/* Config knob for accepting lower sequence numbers */
+void zebra_vxlan_set_accept_bgp_seq(bool set)
+{
+	accept_bgp_seq = set;
+}
+
+bool zebra_vxlan_accept_bgp_seq(void)
+{
+	return accept_bgp_seq;
+}
+
 /* Cleanup BGP EVPN configuration upon client disconnect */
 extern void zebra_evpn_init(void)
 {

zebra/zebra_vxlan.h

@@ -225,6 +225,9 @@ extern int zebra_vxlan_dp_network_mac_del(struct interface *ifp,
 					  struct ethaddr *macaddr,
 					  vlanid_t vid);
 
+extern void zebra_vxlan_set_accept_bgp_seq(bool set);
+extern bool zebra_vxlan_accept_bgp_seq(void);
+
 #ifdef __cplusplus
 }
 #endif