Implements option that controls IPv6 BGP next hops when lladdr is missing.

4 files changed, 46 insertions, 16 deletions

diff --git a/proto/bgp/bgp.c b/proto/bgp/bgp.c
index b38c6b1..cde0276 100644
--- a/proto/bgp/bgp.c
+++ b/proto/bgp/bgp.c
@@ -886,6 +886,10 @@ bgp_check(struct bgp_config *c)
 
   if ((c->local_as == c->remote_as) && (c->rs_client))
     cf_error("Only external neighbor can be RS client");
+
+  /* Different default based on rs_client */
+  if (c->missing_lladdr == 0)
+    c->missing_lladdr = c->rs_client ? MLL_DROP : MLL_SELF;
 }
 
 static char *bgp_state_names[] = { "Idle", "Connect", "Active", "OpenSent", "OpenConfirm", "Established", "Close" };
diff --git a/proto/bgp/bgp.h b/proto/bgp/bgp.h
index c487aaf..c4d0335 100644
--- a/proto/bgp/bgp.h
+++ b/proto/bgp/bgp.h
@@ -23,6 +23,7 @@ struct bgp_config {
   ip_addr multihop_via;			/* Multihop: address to route to */
   ip_addr source_addr;			/* Source address to use */
   int next_hop_self;			/* Always set next hop to local IP address */
+  int missing_lladdr;			/* What we will do when we don' know link-local addr, see MLL_* */
   int compare_path_lengths;		/* Use path lengths when selecting best route */
   int prefer_older;			/* Prefer older routes according to RFC 5004 */
   u32 default_local_pref;		/* Default value for LOCAL_PREF attribute */
@@ -46,6 +47,10 @@ struct bgp_config {
   char *password;			/* Password used for MD5 authentication */
 };
 
+#define MLL_SELF 1
+#define MLL_DROP 2
+#define MLL_IGNORE 3
+
 struct bgp_conn {
   struct bgp_proto *bgp;
   struct birdsock *sk;
diff --git a/proto/bgp/config.Y b/proto/bgp/config.Y
index 9401175..3576946 100644
--- a/proto/bgp/config.Y
+++ b/proto/bgp/config.Y
@@ -22,7 +22,8 @@ CF_KEYWORDS(BGP, LOCAL, NEIGHBOR, AS, HOLD, TIME, CONNECT, RETRY, KEEPALIVE,
 	BGP_PATH, BGP_LOCAL_PREF, BGP_MED, BGP_ORIGIN, BGP_NEXT_HOP,
 	BGP_ATOMIC_AGGR, BGP_AGGREGATOR, BGP_COMMUNITY, SOURCE, ADDRESS,
 	PASSWORD, RR, RS, CLIENT, CLUSTER, ID, AS4, ADVERTISE, IPV4,
-	CAPABILITIES, LIMIT, PASSIVE, PREFER, OLDER)
+	CAPABILITIES, LIMIT, PASSIVE, PREFER, OLDER, MISSING, LLADDR,
+	DROP, IGNORE)
 
 CF_GRAMMAR
 
@@ -64,6 +65,9 @@ bgp_proto:
  | bgp_proto KEEPALIVE TIME expr ';' { BGP_CFG->keepalive_time = $4; }
  | bgp_proto MULTIHOP expr VIA ipa ';' { BGP_CFG->multihop = $3; BGP_CFG->multihop_via = $5; }
  | bgp_proto NEXT HOP SELF ';' { BGP_CFG->next_hop_self = 1; }
+ | bgp_proto MISSING LLADDR SELF ';' { BGP_CFG->missing_lladdr = MLL_SELF; }
+ | bgp_proto MISSING LLADDR DROP ';' { BGP_CFG->missing_lladdr = MLL_DROP; }
+ | bgp_proto MISSING LLADDR IGNORE ';' { BGP_CFG->missing_lladdr = MLL_IGNORE; }
  | bgp_proto PATH METRIC bool ';' { BGP_CFG->compare_path_lengths = $4; }
  | bgp_proto PREFER OLDER bool ';' { BGP_CFG->prefer_older = $4; }
  | bgp_proto DEFAULT BGP_MED expr ';' { BGP_CFG->default_med = $4; }
diff --git a/proto/bgp/packets.c b/proto/bgp/packets.c
index d126fe5..4176c9f 100644
--- a/proto/bgp/packets.c
+++ b/proto/bgp/packets.c
@@ -199,7 +199,7 @@ bgp_create_update(struct bgp_conn *conn, byte *buf)
 
 	  if (a_size < 0)
 	    {
-	      log(L_ERR "%s: Attribute list too long, skipping corresponding route group", p->p.name);
+	      log(L_ERR "%s: Attribute list too long, skipping corresponding routes", p->p.name);
 	      bgp_flush_prefixes(p, buck);
 	      rem_node(&buck->send_node);
 	      bgp_free_bucket(p, buck);
@@ -234,9 +234,9 @@ bgp_create_update(struct bgp_conn *conn, byte *buf)
 {
   struct bgp_proto *p = conn->bgp;
   struct bgp_bucket *buck;
-  int size, second;
+  int size, second, rem_stored;
   int remains = BGP_MAX_PACKET_LENGTH - BGP_HEADER_LENGTH - 4;
-  byte *w, *tmp, *tstart;
+  byte *w, *w_stored, *tmp, *tstart;
   ip_addr *ipp, ip, ip_ll;
   ea_list *ea;
   eattr *nh;
@@ -272,28 +272,25 @@ bgp_create_update(struct bgp_conn *conn, byte *buf)
 	    }
 
 	  DBG("Processing bucket %p\n", buck);
-	  size = bgp_encode_attrs(p, w, buck->eattrs, 2048);
+	  rem_stored = remains;
+	  w_stored = w;
 
+	  size = bgp_encode_attrs(p, w, buck->eattrs, 2048);
 	  if (size < 0)
 	    {
-	      log(L_ERR "%s: Attribute list too long, ignoring corresponding route group", p->p.name);
+	      log(L_ERR "%s: Attribute list too long, skipping corresponding routes", p->p.name);
 	      bgp_flush_prefixes(p, buck);
 	      rem_node(&buck->send_node);
 	      bgp_free_bucket(p, buck);
 	      continue;
 	    }
-
 	  w += size;
 	  remains -= size;
-	  tstart = tmp = bgp_attach_attr_wa(&ea, bgp_linpool, BA_MP_REACH_NLRI, remains-8);
-	  *tmp++ = 0;
-	  *tmp++ = BGP_AF_IPV6;
-	  *tmp++ = 1;
-	  nh = ea_find(buck->eattrs, EA_CODE(EAP_BGP, BA_NEXT_HOP));
-	  ASSERT(nh);
 
-	  /* We have two addresses here in 'nh'. Really.
+	  /* We have two addresses here in NEXT_HOP eattr. Really.
 	     Unless NEXT_HOP was modified by filter */
+	  nh = ea_find(buck->eattrs, EA_CODE(EAP_BGP, BA_NEXT_HOP));
+	  ASSERT(nh);
 	  second = (nh->u.ptr->length == NEXT_HOP_LENGTH);
 	  ipp = (ip_addr *) nh->u.ptr->data;
 	  ip = ipp[0];
@@ -322,12 +319,32 @@ bgp_create_update(struct bgp_conn *conn, byte *buf)
 		    ip_ll = ipp[1];
 		  else
 		    {
-		      ip = p->source_addr;
-		      ip_ll = p->local_link;
+		      switch (p->cf->missing_lladdr)
+			{
+			case MLL_SELF:
+			  ip = p->source_addr;
+			  ip_ll = p->local_link;
+			  break;
+			case MLL_DROP:
+			  log(L_ERR "%s: Missing link-local next hop address, skipping corresponding routes", p->p.name);
+			  w = w_stored;
+			  remains = rem_stored;
+			  bgp_flush_prefixes(p, buck);
+			  rem_node(&buck->send_node);
+			  bgp_free_bucket(p, buck);
+			  continue;
+			case MLL_IGNORE:
+			  break;
+			}
 		    }
 		}
 	    }
 
+	  tstart = tmp = bgp_attach_attr_wa(&ea, bgp_linpool, BA_MP_REACH_NLRI, remains-8);
+	  *tmp++ = 0;
+	  *tmp++ = BGP_AF_IPV6;
+	  *tmp++ = 1;
+
 	  if (ipa_nonzero(ip_ll))
 	    {
 	      *tmp++ = 32;