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>

diff --git a/bgpd/bgp_attr.c b/bgpd/bgp_attr.c
index 439469d61e52b89ae8b4871a8a36a3b289a40880..9ceded921ae7e4d186da3e32ca43a0107a5b4ca3 100644 (file)
--- 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;
     }
 

diff --git a/bgpd/bgp_updgrp_packet.c b/bgpd/bgp_updgrp_packet.c
index dff46a946612ef8f5663b6173eeb0221472117c9..cecb844fcea66058a54e5ffbf0d5e24b2d4be605 100644 (file)
--- a/bgpd/bgp_updgrp_packet.c
+++ b/bgpd/bgp_updgrp_packet.c
@@ -423,12 +423,10 @@ bpacket_reformat_for_peer (struct bpacket *pkt, struct peer_af *paf)
       afi_t    nhafi = AFI_MAX; /* NH AFI is based on nhlen! */
       int route_map_sets_nh;
       nhlen = stream_getc_from (s, vec->offset);
-      if (paf->afi == AFI_IP || paf->afi == AFI_IP6)
-        {
-          nhafi = BGP_NEXTHOP_AFI_FROM_NHLEN(nhlen);
-          if (peer_cap_enhe(peer, paf->afi, paf->safi))
-            nhafi = AFI_IP6;
-        }
+      if (peer_cap_enhe(peer, paf->afi, paf->safi))
+        nhafi = AFI_IP6;
+      else
+        nhafi = BGP_NEXTHOP_AFI_FROM_NHLEN(nhlen);
 
       if (nhafi == AFI_IP)
        {