If no NLRI's are present in an UPDATE message, parse the attributes, but

don't check presence of mandatory attributes. [draft-09]

3 files changed, 16 insertions, 13 deletions

diff --git a/proto/bgp/attrs.c b/proto/bgp/attrs.c
index fa2649c..f7d7b78 100644
--- a/proto/bgp/attrs.c
+++ b/proto/bgp/attrs.c
@@ -676,7 +676,7 @@ bgp_path_loopy(struct bgp_proto *p, eattr *a)
 }
 
 struct rta *
-bgp_decode_attrs(struct bgp_conn *conn, byte *attr, unsigned int len, struct linpool *pool)
+bgp_decode_attrs(struct bgp_conn *conn, byte *attr, unsigned int len, struct linpool *pool, int mandatory)
 {
   struct bgp_proto *bgp = conn->bgp;
   rta *a = lp_alloc(pool, sizeof(struct rta));
@@ -800,13 +800,16 @@ bgp_decode_attrs(struct bgp_conn *conn, byte *attr, unsigned int len, struct lin
     }
 
   /* Check if all mandatory attributes are present */
-  for(i=0; i < sizeof(bgp_mandatory_attrs)/sizeof(bgp_mandatory_attrs[0]); i++)
+  if (mandatory)
     {
-      code = bgp_mandatory_attrs[i];
-      if (!(seen[code/8] & (1 << (code%8))))
+      for(i=0; i < sizeof(bgp_mandatory_attrs)/sizeof(bgp_mandatory_attrs[0]); i++)
 	{
-	  bgp_error(conn, 3, 3, code, 1);
-	  return NULL;
+	  code = bgp_mandatory_attrs[i];
+	  if (!(seen[code/8] & (1 << (code%8))))
+	    {
+	      bgp_error(conn, 3, 3, code, 1);
+	      return NULL;
+	    }
 	}
     }
 
@@ -831,7 +834,7 @@ bgp_decode_attrs(struct bgp_conn *conn, byte *attr, unsigned int len, struct lin
   neigh = neigh_find(&bgp->p, &nexthop, 0) ? : bgp->neigh;
   a->gw = neigh->addr;
   a->iface = neigh->iface;
-  return rta_lookup(a);
+  return a;
 
 malformed:
   bgp_error(conn, 3, 1, len, 0);
diff --git a/proto/bgp/bgp.h b/proto/bgp/bgp.h
index f579ce6..b8e1abc 100644
--- a/proto/bgp/bgp.h
+++ b/proto/bgp/bgp.h
@@ -94,7 +94,7 @@ void bgp_close_conn(struct bgp_conn *c);
 
 /* attrs.c */
 
-struct rta *bgp_decode_attrs(struct bgp_conn *conn, byte *a, unsigned int len, struct linpool *pool);
+struct rta *bgp_decode_attrs(struct bgp_conn *conn, byte *a, unsigned int len, struct linpool *pool, int mandatory);
 int bgp_get_attr(struct eattr *e, byte *buf);
 int bgp_rte_better(struct rte *, struct rte *);
 void bgp_rt_notify(struct proto *, struct network *, struct rte *, struct rte *, struct ea_list *);
diff --git a/proto/bgp/packets.c b/proto/bgp/packets.c
index bec2e50..ccaa91c 100644
--- a/proto/bgp/packets.c
+++ b/proto/bgp/packets.c
@@ -305,6 +305,7 @@ bgp_rx_update(struct bgp_conn *conn, byte *pkt, int len)
   int withdrawn_len, attr_len, nlri_len, pxlen;
   net *n;
   rte e;
+  rta *a0;
   rta *a = NULL;
 
   DBG("BGP: UPDATE\n");
@@ -341,11 +342,10 @@ bgp_rx_update(struct bgp_conn *conn, byte *pkt, int len)
 	rte_update(bgp->p.table, n, &bgp->p, NULL);
     }
 
-  if (nlri_len)
+  a0 = bgp_decode_attrs(conn, attrs, attr_len, bgp_linpool, nlri_len);
+  if (a0 && nlri_len)
     {
-      a = bgp_decode_attrs(conn, attrs, attr_len, bgp_linpool);
-      if (!a)
-	return;
+      a = rta_lookup(a0);
       while (nlri_len)
 	{
 	  rte *e;
@@ -357,9 +357,9 @@ bgp_rx_update(struct bgp_conn *conn, byte *pkt, int len)
 	  e->pflags = 0;
 	  rte_update(bgp->p.table, n, &bgp->p, e);
 	}
-      lp_flush(bgp_linpool);
       rta_free(a);
     }
+  lp_flush(bgp_linpool);
   return;
 
 malformed: