server: Auto derived ES-Import RT for EVPN Ethernet Segment route

According to RFC7432, the ES-Import RT can be derived automatically
when using the ESI Types 1, 2 and 3.

This patch enables to derive automatically the ES-Import RT for the
given path from BgpServer's API.

Signed-off-by: IWASE Yusuke <iwase.yusuke0@gmail.com>

1 files changed, 30 insertions, 9 deletions

diff --git a/server/server.go b/server/server.go
index 7d6194f4..050ab81d 100644
--- a/server/server.go
+++ b/server/server.go
@@ -1285,20 +1285,41 @@ func (server *BgpServer) fixupApiPath(vrfId string, pathList []*table.Path) erro
 			}
 		}
 
-		if path.GetRouteFamily() == bgp.RF_EVPN {
-			nlri := path.GetNlri()
-			evpnNlri := nlri.(*bgp.EVPNNLRI)
-			if evpnNlri.RouteType == bgp.EVPN_ROUTE_TYPE_MAC_IP_ADVERTISEMENT {
-				macIpAdv := evpnNlri.RouteTypeData.(*bgp.EVPNMacIPAdvertisementRoute)
-				etag := macIpAdv.ETag
-				mac := macIpAdv.MacAddress
+		// Address Family specific Handling
+		switch nlri := path.GetNlri().(type) {
+		case *bgp.EVPNNLRI:
+			switch r := nlri.RouteTypeData.(type) {
+			case *bgp.EVPNMacIPAdvertisementRoute:
+				// MAC Mobility Extended Community
 				paths := server.globalRib.GetBestPathList(table.GLOBAL_RIB_NAME, []bgp.RouteFamily{bgp.RF_EVPN})
-				if m := getMacMobilityExtendedCommunity(etag, mac, paths); m != nil {
+				if m := getMacMobilityExtendedCommunity(r.ETag, r.MacAddress, paths); m != nil {
 					path.SetExtCommunities([]bgp.ExtendedCommunityInterface{m}, false)
 				}
+			case *bgp.EVPNEthernetSegmentRoute:
+				// RFC7432: BGP MPLS-Based Ethernet VPN
+				// 7.6. ES-Import Route Target
+				// The value is derived automatically for the ESI Types 1, 2,
+				// and 3, by encoding the high-order 6-octet portion of the 9-octet ESI
+				// Value, which corresponds to a MAC address, in the ES-Import Route
+				// Target.
+				// Note: If the given path already has the ES-Import Route Target,
+				// skips deriving a new one.
+				found := false
+				for _, extComm := range path.GetExtCommunities() {
+					if _, found = extComm.(*bgp.ESImportRouteTarget); found {
+						break
+					}
+				}
+				if !found {
+					switch r.ESI.Type {
+					case bgp.ESI_LACP, bgp.ESI_MSTP, bgp.ESI_MAC:
+						mac := net.HardwareAddr(r.ESI.Value[0:6])
+						rt := &bgp.ESImportRouteTarget{ESImport: mac}
+						path.SetExtCommunities([]bgp.ExtendedCommunityInterface{rt}, false)
+					}
+				}
 			}
 		}
-
 	}
 	return nil
 }