bgpd: do not advertise ipv6 host routes with l3-vni related ext-comm

Currently, kernel doesn't support ipv6 routes with ipv4 nexthops.
To avoid the crash,
we will only attach l3-vni related
RTs/ecommunities only to ipv4 host routes.

Ticket: CM-18743
Review: ccr-6912
Testing: Manaul

Signed-off-by: Mitesh Kanjariya <mitesh@cumulusnetworks.com>

diff --git a/bgpd/bgp_evpn.c b/bgpd/bgp_evpn.c
index 840828228b2ad734b3b3af97e95293d28d48a676..27d7d7aab042faf934b2fa5d5aa338768339e497 100644 (file)
--- a/bgpd/bgp_evpn.c
+++ b/bgpd/bgp_evpn.c
@@ -604,8 +604,15 @@ static int bgp_zebra_send_remote_vtep(struct bgp *bgp, struct bgpevpn *vpn,
 /*
  * Build extended communities for EVPN route. RT and ENCAP are
  * applicable to all routes.
+ * TODO: currently kernel doesnt support ipv6 routes with ipv4 nexthops.
+ * This means that we can't do symmetric routing for ipv6 hosts routes
+ * in the same way as ipv4 host routes.
+ * We wont attach l3-vni related RTs for ipv6 routes.
+ * For now, We will only adevrtise ipv4 host routes
+ * with L3-VNI related ext-comm.
  */
-static void build_evpn_route_extcomm(struct bgpevpn *vpn, struct attr *attr)
+static void build_evpn_route_extcomm(struct bgpevpn *vpn, struct attr *attr,
+                                    afi_t afi)
 {
        struct ecommunity ecom_encap;
        struct ecommunity ecom_sticky;
@@ -633,12 +640,17 @@ static void build_evpn_route_extcomm(struct bgpevpn *vpn, struct attr *attr)
        for (ALL_LIST_ELEMENTS(vpn->export_rtl, node, nnode, ecom))
                attr->ecommunity = ecommunity_merge(attr->ecommunity, ecom);
 
-       /* Add the export RTs for L3VNI */
-       vrf_export_rtl = bgpevpn_get_vrf_export_rtl(vpn);
-       if (vrf_export_rtl && !list_isempty(vrf_export_rtl)) {
-               for (ALL_LIST_ELEMENTS(vrf_export_rtl, node, nnode, ecom))
-                       attr->ecommunity = ecommunity_merge(attr->ecommunity,
-                                                           ecom);
+       /* Add the export RTs for L3VNI - currently only supported for IPV4 host
+        * routes */
+       if (afi == AFI_IP) {
+               vrf_export_rtl = bgpevpn_get_vrf_export_rtl(vpn);
+               if (vrf_export_rtl && !list_isempty(vrf_export_rtl)) {
+                       for (ALL_LIST_ELEMENTS(vrf_export_rtl, node, nnode,
+                                              ecom))
+                               attr->ecommunity =
+                                       ecommunity_merge(attr->ecommunity,
+                                                        ecom);
+               }
        }
 
        if (attr->sticky) {
@@ -651,7 +663,7 @@ static void build_evpn_route_extcomm(struct bgpevpn *vpn, struct attr *attr)
                        ecommunity_merge(attr->ecommunity, &ecom_sticky);
        }
 
-       if (!is_zero_mac(&attr->rmac)) {
+       if (afi == AFI_IP && !is_zero_mac(&attr->rmac)) {
                memset(&ecom_rmac, 0, sizeof(ecom_rmac));
                encode_rmac_extcomm(&eval_rmac, &attr->rmac);
                ecom_rmac.size = 1;
@@ -1033,7 +1045,9 @@ static int update_evpn_route(struct bgp *bgp, struct bgpevpn *vpn,
        bgpevpn_get_rmac(vpn, &attr.rmac);
 
        /* Set up RT and ENCAP extended community. */
-       build_evpn_route_extcomm(vpn, &attr);
+       build_evpn_route_extcomm(vpn, &attr,
+                                IS_EVPN_PREFIX_IPADDR_V4(p) ?
+                                       AFI_IP : AFI_IP6);
 
        /* First, create (or fetch) route node within the VNI. */
        /* NOTE: There is no RD here. */
@@ -1162,12 +1176,16 @@ static int update_all_type2_routes(struct bgp *bgp, struct bgpevpn *vpn)
        struct bgp_info *ri;
        struct attr attr;
        struct attr attr_sticky;
+       struct attr attr_ip6;
+       struct attr attr_sticky_ip6;
        struct attr *attr_new;
 
        afi = AFI_L2VPN;
        safi = SAFI_EVPN;
        memset(&attr, 0, sizeof(struct attr));
        memset(&attr_sticky, 0, sizeof(struct attr));
+       memset(&attr_ip6, 0, sizeof(struct attr));
+       memset(&attr_sticky_ip6, 0, sizeof(struct attr));
 
        /* Build path-attribute - all type-2 routes for this VNI will share the
         * same path attribute.
@@ -1183,10 +1201,23 @@ static int update_all_type2_routes(struct bgp *bgp, struct bgpevpn *vpn)
        attr_sticky.mp_nexthop_len = BGP_ATTR_NHLEN_IPV4;
        attr_sticky.sticky = 1;
        bgpevpn_get_rmac(vpn, &attr_sticky.rmac);
+       bgp_attr_default_set(&attr_ip6, BGP_ORIGIN_IGP);
+       bgp_attr_default_set(&attr_sticky_ip6, BGP_ORIGIN_IGP);
+       attr_ip6.nexthop = vpn->originator_ip;
+       attr_ip6.mp_nexthop_global_in = vpn->originator_ip;
+       attr_ip6.mp_nexthop_len = BGP_ATTR_NHLEN_IPV4;
+       bgpevpn_get_rmac(vpn, &attr_ip6.rmac);
+       attr_sticky_ip6.nexthop = vpn->originator_ip;
+       attr_sticky_ip6.mp_nexthop_global_in = vpn->originator_ip;
+       attr_sticky_ip6.mp_nexthop_len = BGP_ATTR_NHLEN_IPV4;
+       attr_sticky_ip6.sticky = 1;
+       bgpevpn_get_rmac(vpn, &attr_sticky_ip6.rmac);
 
        /* Set up RT, ENCAP and sticky MAC extended community. */
-       build_evpn_route_extcomm(vpn, &attr);
-       build_evpn_route_extcomm(vpn, &attr_sticky);
+       build_evpn_route_extcomm(vpn, &attr, AFI_IP);
+       build_evpn_route_extcomm(vpn, &attr_sticky, AFI_IP);
+       build_evpn_route_extcomm(vpn, &attr_ip6, AFI_IP6);
+       build_evpn_route_extcomm(vpn, &attr_sticky_ip6, AFI_IP6);
 
        /* Walk this VNI's route table and update local type-2 routes. For any
         * routes updated, update corresponding entry in the global table too.
@@ -1200,12 +1231,24 @@ static int update_all_type2_routes(struct bgp *bgp, struct bgpevpn *vpn)
                if (evp->prefix.route_type != BGP_EVPN_MAC_IP_ROUTE)
                        continue;
 
-               if (evpn_route_is_sticky(bgp, rn))
-                       update_evpn_route_entry(bgp, vpn, afi, safi, rn,
-                                               &attr_sticky, 0, 1, &ri, 0);
-               else
-                       update_evpn_route_entry(bgp, vpn, afi, safi, rn, &attr,
-                                               0, 1, &ri, 0);
+               if (IS_EVPN_PREFIX_IPADDR_V4(evp)) {
+                       if (evpn_route_is_sticky(bgp, rn))
+                               update_evpn_route_entry(bgp, vpn, afi, safi, rn,
+                                                       &attr_sticky, 0, 1,
+                                                       &ri, 0);
+                       else
+                               update_evpn_route_entry(bgp, vpn, afi, safi, rn,
+                                                       &attr, 0, 1, &ri, 0);
+               } else {
+                       if (evpn_route_is_sticky(bgp, rn))
+                               update_evpn_route_entry(bgp, vpn, afi, safi, rn,
+                                                       &attr_sticky_ip6, 0, 1,
+                                                       &ri, 0);
+                       else
+                               update_evpn_route_entry(bgp, vpn, afi, safi, rn,
+                                                       &attr_ip6, 0, 1,
+                                                       &ri, 0);
+               }
 
                /* If a local route exists for this prefix, we need to update
                 * the global routing table too.