bgpd: Fix next hop setting for EVPN

The next hop for EVPN routes must be an IPv4 or IPv6 address as per
RFC 7432. Ensure this is correctly handled. Also, ensure there
are correct checks for AFI_L2VPN and nexthop AFI is not AFI_L2VPN.

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

1 files changed, 12 insertions, 43 deletions

diff --git a/bgpd/bgp_attr.c b/bgpd/bgp_attr.c
index 439469d61..9ceded921 100644
--- a/bgpd/bgp_attr.c
+++ b/bgpd/bgp_attr.c
@@ -2841,16 +2841,14 @@ bgp_packet_mpattr_start (struct stream *s, struct peer *peer,
   stream_putc (s, pkt_safi);   /* SAFI */
 
   /* Nexthop AFI */
-  if (peer_cap_enhe(peer, afi, safi)) {
-    nh_afi = AFI_IP6;
-  } else {
-    if (afi == AFI_L2VPN)
-      nh_afi = AFI_L2VPN;
-    else if (safi == SAFI_LABELED_UNICAST)
-      nh_afi = afi;
-    else
-      nh_afi = BGP_NEXTHOP_AFI_FROM_NHLEN(attr->extra->mp_nexthop_len);
-  }
+  if (afi == AFI_IP && safi == SAFI_UNICAST)
+    {
+      nh_afi = peer_cap_enhe (peer, afi, safi) ? AFI_IP6 : AFI_IP;
+    }
+  else if (safi == SAFI_LABELED_UNICAST)
+    nh_afi = afi;
+  else
+    nh_afi = BGP_NEXTHOP_AFI_FROM_NHLEN(attr->extra->mp_nexthop_len);
 
   /* Nexthop */
   bpacket_attr_vec_arr_set_vec (vecarr, BGP_ATTR_VEC_NH, s, attr);
@@ -2872,6 +2870,7 @@ bgp_packet_mpattr_start (struct stream *s, struct peer *peer,
 	  stream_put (s, &attr->extra->mp_nexthop_global_in, 4);
 	  break;
 	case SAFI_ENCAP:
+	case SAFI_EVPN:
 	  stream_putc (s, 4);
 	  stream_put (s, &attr->extra->mp_nexthop_global_in, 4);
 	  break;
@@ -2885,6 +2884,7 @@ bgp_packet_mpattr_start (struct stream *s, struct peer *peer,
       case SAFI_UNICAST:
       case SAFI_MULTICAST:
       case SAFI_LABELED_UNICAST:
+      case SAFI_EVPN:
 	{
 	  struct attr_extra *attre = attr->extra;
 
@@ -2930,40 +2930,9 @@ bgp_packet_mpattr_start (struct stream *s, struct peer *peer,
 	break;
       }
       break;
-    case AFI_L2VPN:
-      switch (safi)
-      {
-      case SAFI_EVPN:
-          if (attr->extra->mp_nexthop_len == BGP_ATTR_NHLEN_VPNV4)
-            {
-              stream_putc (s, 12);
-              stream_putl (s, 0);   /* RD = 0, per RFC */
-              stream_putl (s, 0);
-              stream_put (s, &attr->extra->mp_nexthop_global_in, 4);
-            }
-          else if (attr->extra->mp_nexthop_len == BGP_ATTR_NHLEN_IPV6_GLOBAL)
-            {
-              stream_putc (s, 24);
-              stream_putl (s, 0);   /* RD = 0, per RFC */
-              stream_putl (s, 0);
-              stream_put (s, &attr->extra->mp_nexthop_global, IPV6_MAX_BYTELEN);
-            }
-          else if (attr->extra->mp_nexthop_len == BGP_ATTR_NHLEN_IPV6_GLOBAL_AND_LL)
-            {
-              stream_putc (s, 48);
-              stream_putl (s, 0);   /* RD = 0, per RFC */
-              stream_putl (s, 0);
-              stream_put (s, &attr->extra->mp_nexthop_global, IPV6_MAX_BYTELEN);
-              stream_putl (s, 0);   /* RD = 0, per RFC */
-              stream_putl (s, 0);
-              stream_put (s, &attr->extra->mp_nexthop_local, IPV6_MAX_BYTELEN);
-            }
-	  break;
-        break;
-      default:
-        break;
-      }
     default:
+      zlog_err ("Bad nexthop when sening to %s, AFI %u SAFI %u nhlen %d",
+                peer->host, afi, safi, attr->extra->mp_nexthop_len);
       break;
     }