bgpd: general MP/SAFI improvements

This fixes some minor mixups particularly in MPLS-related SAFIs, as well
as doing some stylistic changes & adding comments.

Signed-off-by: Lou Berger <lberger@labn.net>
Reviewed-by: David Lamparter <equinox@opensourcerouting.org>
(cherry picked from commit 050defe816e4bd4cac7b028f69e45cb1974ca96d)

Conflicts:
	bgpd/bgp_attr.c
	bgpd/bgp_attr.h
	bgpd/bgp_packet.c
	bgpd/bgp_route.c
	bgpd/bgp_route.h

bgpd/bgp_attr.c

@@ -2208,8 +2208,9 @@ bgp_packet_mpattr_start (struct stream *s, afi_t afi, safi_t safi, afi_t nh_afi,
   stream_putc (s, BGP_ATTR_MP_REACH_NLRI);
   sizep = stream_get_endp (s);
   stream_putw (s, 0);	/* Marker: Attribute length. */
-  stream_putw (s, afi);	/* AFI */
+
-  stream_putc (s, safi);	/* SAFI */
+  stream_putw (s, afi);
+  stream_putc (s, (safi == SAFI_MPLS_VPN) ? SAFI_MPLS_LABELED_VPN : safi);
 
   /* Nexthop */
   switch (nh_afi)
@@ -2217,7 +2218,6 @@ bgp_packet_mpattr_start (struct stream *s, afi_t afi, safi_t safi, afi_t nh_afi,
     case AFI_IP:
       switch (safi)
 	{
-	case SAFI_UNICAST:
 	case SAFI_MULTICAST:
 	  bpacket_attr_vec_arr_set_vec (vecarr, BGP_ATTR_VEC_NH, s, attr);
 	  stream_putc (s, 4);
@@ -2226,10 +2226,11 @@ bgp_packet_mpattr_start (struct stream *s, afi_t afi, safi_t safi, afi_t nh_afi,
 	case SAFI_MPLS_VPN:
 	  bpacket_attr_vec_arr_set_vec (vecarr, BGP_ATTR_VEC_NH, s, attr);
 	  stream_putc (s, 12);
-	  stream_putl (s, 0);
+	  stream_putl (s, 0);   /* RD = 0, per RFC */
 	  stream_putl (s, 0);
 	  stream_put (s, &attr->extra->mp_nexthop_global_in, 4);
 	  break;
+	case SAFI_UNICAST:      /* invalid for IPv4 */
 	default:
 	  break;
 	}
@@ -2250,6 +2251,28 @@ bgp_packet_mpattr_start (struct stream *s, afi_t afi, safi_t safi, afi_t nh_afi,
 	  if (attre->mp_nexthop_len == BGP_ATTR_NHLEN_IPV6_GLOBAL_AND_LL)
 	    stream_put (s, &attre->mp_nexthop_local, IPV6_MAX_BYTELEN);
 	}
+	break;
+      case SAFI_MPLS_VPN:
+	{
+	  struct attr_extra *attre = attr->extra;
+
+	  assert (attr->extra);
+          if (attre->mp_nexthop_len == 16) {
+            stream_putc (s, 24);
+            stream_putl (s, 0);   /* RD = 0, per RFC */
+            stream_putl (s, 0);
+            stream_put (s, &attre->mp_nexthop_global, 16);
+          } else if (attre->mp_nexthop_len == 32) {
+            stream_putc (s, 48);
+            stream_putl (s, 0);   /* RD = 0, per RFC */
+            stream_putl (s, 0);
+            stream_put (s, &attre->mp_nexthop_global, 16);
+            stream_putl (s, 0);   /* RD = 0, per RFC */
+            stream_putl (s, 0);
+            stream_put (s, &attre->mp_nexthop_local, 16);
+          }
+        }
+	break;
       default:
 	break;
       }
@@ -2270,24 +2293,27 @@ bgp_packet_mpattr_prefix (struct stream *s, afi_t afi, safi_t safi,
                           u_char *tag, int addpath_encode,
                           u_int32_t addpath_tx_id)
 {
-  switch (safi)
+  if (safi == SAFI_MPLS_VPN)
     {
-    case SAFI_MPLS_VPN:
-      /* addpath TX ID */
       if (addpath_encode)
         stream_putl(s, addpath_tx_id);
-
       /* Tag, RD, Prefix write. */
       stream_putc (s, p->prefixlen + 88);
       stream_put (s, tag, 3);
       stream_put (s, prd->val, 8);
       stream_put (s, &p->u.prefix, PSIZE (p->prefixlen));
-      break;
-    default:
-      /* Prefix write. */
-      stream_put_prefix_addpath (s, p, addpath_encode, addpath_tx_id);
-      break;
     }
+  else
+    stream_put_prefix_addpath (s, p, addpath_encode, addpath_tx_id);
+}
+
+size_t
+bgp_packet_mpattr_prefix_size (afi_t afi, safi_t safi, struct prefix *p)
+{
+  int size = PSIZE (p->prefixlen);
+  if (safi == SAFI_MPLS_VPN)
+      size += 88;
+  return size;
 }
 
 void
@@ -2314,7 +2340,6 @@ bgp_packet_attribute (struct bgp *bgp, struct peer *peer,
   int send_as4_path = 0;
   int send_as4_aggregator = 0;
   int use32bit = (CHECK_FLAG (peer->cap, PEER_CAP_AS4_RCV)) ? 1 : 0;
-  size_t mpattrlen_pos = 0;
 
   if (! bgp)
     bgp = peer->bgp;
@@ -2325,6 +2350,8 @@ bgp_packet_attribute (struct bgp *bgp, struct peer *peer,
   if (p && !((afi == AFI_IP && safi == SAFI_UNICAST) &&
               !peer_cap_enhe(peer)))
     {
+      size_t mpattrlen_pos = 0;
+
       mpattrlen_pos = bgp_packet_mpattr_start(s, afi, safi,
                                     (peer_cap_enhe(peer) ? AFI_IP6 : afi),
                                     vecarr, attr);
@@ -2403,7 +2430,7 @@ bgp_packet_attribute (struct bgp *bgp, struct peer *peer,
       send_as4_path = 1; /* we'll do this later, at the correct place */
   
   /* Nexthop attribute. */
-  if (afi == AFI_IP && !peer_cap_enhe(peer))
+  if (afi == AFI_IP && safi == SAFI_UNICAST && !peer_cap_enhe(peer))
     {
       if (attr->flag & ATTR_FLAG_BIT (BGP_ATTR_NEXT_HOP))
         {
@@ -2689,8 +2716,7 @@ bgp_packet_mpunreach_start (struct stream *s, afi_t afi, safi_t safi)
   stream_putw (s, 0);		/* Length of this attribute. */
 
   stream_putw (s, afi);
-  safi = (safi == SAFI_MPLS_VPN) ? SAFI_MPLS_LABELED_VPN : safi;
+  stream_putc (s, (safi == SAFI_MPLS_VPN) ? SAFI_MPLS_LABELED_VPN : safi);
-  stream_putc (s, safi);
   return attrlen_pnt;
 }
 
@@ -2718,12 +2744,7 @@ bgp_packet_mpunreach_prefix (struct stream *s, struct prefix *p,
 void
 bgp_packet_mpunreach_end (struct stream *s, size_t attrlen_pnt)
 {
-  bgp_size_t size;
+  bgp_packet_mpattr_end (s, attrlen_pnt);
-
-  /* Set MP attribute length. Don't count the (2) bytes used to encode
-     the attr length */
-  size = stream_get_endp (s) - attrlen_pnt - 2;
-  stream_putw_at (s, attrlen_pnt, size);
 }
 
 /* Initialization of attribute. */

bgpd/bgp_attr.h

@@ -239,6 +239,8 @@ extern void bgp_packet_mpattr_prefix(struct stream *s, afi_t afi, safi_t safi,
 				     struct prefix *p, struct prefix_rd *prd,
 				     u_char *tag, int addpath_encode,
                                      u_int32_t addpath_tx_id);
+extern size_t bgp_packet_mpattr_prefix_size(afi_t afi, safi_t safi,
+                                            struct prefix *p);
 extern void bgp_packet_mpattr_end(struct stream *s, size_t sizep);
 
 extern size_t bgp_packet_mpunreach_start (struct stream *s, afi_t afi,

bgpd/bgp_mplsvpn.c

@@ -206,13 +206,10 @@ bgp_nlri_parse_vpn (struct peer *peer, struct attr *attr,
           decode_rd_ip (pnt + 5, &rd_ip);
           break;
 
-        case RD_TYPE_EOI:
+	default:
-          break;
+	  zlog_err ("Unknown RD type %d", type);
-
+          break;  /* just report */
-        default:
+      }
-          zlog_err ("Invalid RD type %d", type);
-          return -1;
-        }
 
       p.prefixlen = prefixlen - VPN_PREFIXLEN_MIN_BYTES*8;
       memcpy (&p.u.prefix, pnt + VPN_PREFIXLEN_MIN_BYTES, 
@@ -348,14 +345,6 @@ prefix_rd2str (struct prefix_rd *prd, char *buf, size_t size)
       snprintf (buf, size, "%s:%d", inet_ntoa (rd_ip.ip), rd_ip.val);
       return buf;
     }
-  else if (type == RD_TYPE_EOI)
-    {
-      snprintf(buf, size, "LHI:%d, %02x:%02x:%02x:%02x:%02x:%02x",
-               pnt[1], /* LHI */
-               pnt[2], pnt[3], pnt[4], pnt[5], pnt[6], pnt[7]); /* MAC */
-      return buf;
-    }
-
   return NULL;
 }
 

bgpd/bgp_mplsvpn.h

@@ -24,7 +24,6 @@ Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
 #define RD_TYPE_AS      0
 #define RD_TYPE_IP      1
 #define RD_TYPE_AS4     2
-#define RD_TYPE_EOI	0xff00
 
 #define RD_ADDRSTRLEN  28
 

bgpd/bgp_routemap.c

@@ -2369,6 +2369,7 @@ route_set_vpnv4_nexthop (void *rule, struct prefix *prefix,
     
       /* Set next hop value. */ 
       (bgp_attr_extra_get (bgp_info->attr))->mp_nexthop_global_in = *address;
+      (bgp_attr_extra_get (bgp_info->attr))->mp_nexthop_len = 4;
     }
 
   return RMAP_OKAY;

bgpd/bgp_updgrp_packet.c

@@ -666,7 +666,8 @@ subgroup_update_packet (struct update_subgroup *subgrp)
 
       space_remaining = STREAM_CONCAT_REMAIN (s, snlri, STREAM_SIZE(s)) -
                         BGP_MAX_PACKET_SIZE_OVERFLOW;
-      space_needed = BGP_NLRI_LENGTH + PSIZE (rn->p.prefixlen);
+      space_needed = BGP_NLRI_LENGTH +
+                     bgp_packet_mpattr_prefix_size (afi, safi, &rn->p);
 
       /* When remaining space can't include NLRI and it's length.  */
       if (space_remaining < space_needed)
@@ -675,10 +676,18 @@ subgroup_update_packet (struct update_subgroup *subgrp)
       /* If packet is empty, set attribute. */
       if (stream_empty (s))
 	{
+	  struct prefix_rd *prd = NULL;
+	  u_char *tag = NULL;
 	  struct peer *from = NULL;
 
+	  if (rn->prn)
+	    prd = (struct prefix_rd *) &rn->prn->p;
 	  if (binfo)
-	    from = binfo->peer;
+            {
+              from = binfo->peer;
+              if (binfo->extra)
+                tag = binfo->extra->tag;
+            }
 
 	  /* 1: Write the BGP message header - 16 bytes marker, 2 bytes length,
 	   * one byte message type.
@@ -701,8 +710,8 @@ subgroup_update_packet (struct update_subgroup *subgrp)
 	  /* 5: Encode all the attributes, except MP_REACH_NLRI attr. */
 	  total_attr_len = bgp_packet_attribute (NULL, peer, s,
 						 adv->baa->attr, &vecarr,
-						 NULL, afi, safi,
+						 &rn->p, afi, safi,
-						 from, NULL, NULL, 0, 0);
+						 from, prd, tag, 0, 0);
 
           space_remaining = STREAM_CONCAT_REMAIN (s, snlri, STREAM_SIZE(s)) -
                             BGP_MAX_PACKET_SIZE_OVERFLOW;