table: fix local-pref handling for external peer

remove a local-pref path attribute when peer is external and
not a confederation member.

Signed-off-by: ISHIDA Wataru <ishida.wataru@lab.ntt.co.jp>

3 files changed, 35 insertions, 9 deletions

diff --git a/config/util.go b/config/util.go
new file mode 100644
index 00000000..26ab7004
--- /dev/null
+++ b/config/util.go
@@ -0,0 +1,27 @@
+// Copyright (C) 2015 Nippon Telegraph and Telephone Corporation.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+// implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package config
+
+func IsConfederationMember(g *Global, p *Neighbor) bool {
+	if p.NeighborConfig.PeerAs != g.GlobalConfig.As {
+		for _, member := range g.Confederation.ConfederationConfig.MemberAs {
+			if member == p.NeighborConfig.PeerAs {
+				return true
+			}
+		}
+	}
+	return false
+}
diff --git a/server/peer.go b/server/peer.go
index 95d3839e..cc695859 100644
--- a/server/peer.go
+++ b/server/peer.go
@@ -76,15 +76,7 @@ func NewPeer(g config.Global, conf config.Neighbor, loc *table.TableManager) *Pe
 	}
 	peer.adjRib = table.NewAdjRib(peer.configuredRFlist())
 	peer.fsm = NewFSM(&g, &conf)
-	if conf.NeighborConfig.PeerAs != g.GlobalConfig.As {
-		for _, member := range g.Confederation.ConfederationConfig.MemberAs {
-			if member == conf.NeighborConfig.PeerAs {
-				peer.isConfederationMember = true
-				break
-			}
-		}
-	}
-
+	peer.isConfederationMember = config.IsConfederationMember(&g, &conf)
 	return peer
 }
 
diff --git a/table/path.go b/table/path.go
index 38c8443a..b2c9bb55 100644
--- a/table/path.go
+++ b/table/path.go
@@ -99,6 +99,13 @@ func (path *Path) UpdatePathAttrs(global *config.Global, peer *config.Neighbor)
 		if idx >= 0 && !path.IsLocal() {
 			path.pathAttrs = append(path.pathAttrs[:idx], path.pathAttrs[idx+1:]...)
 		}
+
+		// remove local-pref attribute
+		idx, _ = path.getPathAttr(bgp.BGP_ATTR_TYPE_LOCAL_PREF)
+		if idx >= 0 && !config.IsConfederationMember(global, peer) {
+			path.pathAttrs = append(path.pathAttrs[:idx], path.pathAttrs[idx+1:]...)
+		}
+
 	} else if peer.NeighborConfig.PeerType == config.PEER_TYPE_INTERNAL {
 		// NEXTHOP handling for iBGP
 		// if the path generated locally set local address as nexthop.