bgpd: router bgp export leaked vpn routes

two bgp vrf instance has vrf route leak configured,
when a source vrf x is deleted, its leaked routes are cleaned
up from the destination and vpn table.

With this change when a source bgp instance is reconfigured,
export its routes back to destination vrfs where it is configured
as leak.

Ticket:CM-20534 CM-24484
Reviewed By:
Testing Done:

configure vrf leak between two vrf intances,
delete and readd source vrf and checked its routes
exported to vpn table and leaked vrfs table.

Signed-off-by: Chirag Shah <chirag@cumulusnetworks.com>

3 files changed, 75 insertions, 0 deletions

diff --git a/bgpd/bgp_mplsvpn.c b/bgpd/bgp_mplsvpn.c
index e540815928..1156810510 100644
--- a/bgpd/bgp_mplsvpn.c
+++ b/bgpd/bgp_mplsvpn.c
@@ -2598,3 +2598,75 @@ int bgp_vpn_leak_unimport(struct bgp *from_bgp, struct vty *vty)
 	}
 	return 0;
 }
+
+/* When a router bgp is configured, there could be a bgp vrf
+ * instance importing routes from this newly configured
+ * bgp vrf instance. Export routes from configured
+ * bgp vrf to VPN.
+ * VRF Y has import from bgp vrf x,
+ * when a bgp vrf x instance is created, export its routes
+ * to VRF Y instance.
+ */
+void bgp_vpn_leak_export(struct bgp *from_bgp)
+{
+	afi_t afi;
+	const char *export_name;
+	char *vname;
+	struct listnode *node, *next;
+	struct ecommunity *ecom;
+	vpn_policy_direction_t idir, edir;
+	safi_t safi = SAFI_UNICAST;
+	struct bgp *to_bgp;
+	int debug;
+
+	debug = (BGP_DEBUG(vpn, VPN_LEAK_TO_VRF) |
+		     BGP_DEBUG(vpn, VPN_LEAK_FROM_VRF));
+
+	idir = BGP_VPN_POLICY_DIR_FROMVPN;
+	edir = BGP_VPN_POLICY_DIR_TOVPN;
+
+	export_name = (from_bgp->name ? XSTRDUP(MTYPE_TMP, from_bgp->name)
+			       : XSTRDUP(MTYPE_TMP, VRF_DEFAULT_NAME));
+
+	for (afi = 0; afi < AFI_MAX; ++afi) {
+		/* vrf leak is for IPv4 and IPv6 Unicast only */
+		if (afi != AFI_IP && afi != AFI_IP6)
+			continue;
+
+		for (ALL_LIST_ELEMENTS_RO(bm->bgp, next, to_bgp)) {
+			if (from_bgp == to_bgp)
+				continue;
+
+			/* bgp instance has import list, check to see if newly
+			 * configured bgp instance is the list.
+			 */
+			struct vpn_policy *to_vpolicy;
+
+			to_vpolicy = &(to_bgp->vpn_policy[afi]);
+			for (ALL_LIST_ELEMENTS_RO(to_vpolicy->import_vrf,
+						  node, vname)) {
+				if (strcmp(vname, export_name) != 0)
+					continue;
+
+				if (debug)
+					zlog_debug("%s: found from_bgp %s in to_bgp %s import list, import routes.",
+					   __func__,
+					   export_name, to_bgp->name_pretty);
+
+				ecom = from_bgp->vpn_policy[afi].rtlist[edir];
+				/* remove import rt, it will be readded
+				 * as part of import from vrf.
+				 */
+				if (ecom)
+					ecommunity_del_val(
+						to_vpolicy->rtlist[idir],
+						(struct ecommunity_val *)
+							ecom->val);
+				vrf_import_from_vrf(to_bgp, from_bgp,
+						    afi, safi);
+				break;
+
+			}
+		}
+	}
+}
diff --git a/bgpd/bgp_mplsvpn.h b/bgpd/bgp_mplsvpn.h
index 154eb2be06..3234f7fc9d 100644
--- a/bgpd/bgp_mplsvpn.h
+++ b/bgpd/bgp_mplsvpn.h
@@ -267,5 +267,6 @@ extern void vpn_leak_postchange_all(void);
 extern void vpn_handle_router_id_update(struct bgp *bgp, bool withdraw,
 					bool is_config);
 extern int bgp_vpn_leak_unimport(struct bgp *from_bgp, struct vty *vty);
+extern void bgp_vpn_leak_export(struct bgp *from_bgp);
 
 #endif /* _QUAGGA_BGP_MPLSVPN_H */
diff --git a/bgpd/bgp_vty.c b/bgpd/bgp_vty.c
index 2e836fb40f..bde4b52af5 100644
--- a/bgpd/bgp_vty.c
+++ b/bgpd/bgp_vty.c
@@ -1003,6 +1003,8 @@ DEFUN_NOSH (router_bgp,
 		if (is_new_bgp && inst_type == BGP_INSTANCE_TYPE_DEFAULT)
 			vpn_leak_postchange_all();
 
+		if (inst_type == BGP_INSTANCE_TYPE_VRF)
+			bgp_vpn_leak_export(bgp);
 		/* Pending: handle when user tries to change a view to vrf n vv.
 		 */
 	}