Allow multiple routes to be added for the same prefix.

Enables ECMP

Fixes: containernetworking#601

Signed-off-by: Michael Cambria <mcambria@redhat.com>

pkg/ipam/ipam_linux.go

@@ -113,11 +113,14 @@ func ConfigureIface(ifName string, res *current.Result) error {
 				gw = v6gw
 			}
 		}
-		if err = ip.AddRoute(&r.Dst, gw, link); err != nil {
-			// we skip over duplicate routes as we assume the first one wins
-			if !os.IsExist(err) {
-				return fmt.Errorf("failed to add route '%v via %v dev %v': %v", r.Dst, gw, ifName, err)
-			}
+		route := netlink.Route{
+			Dst:       &r.Dst,
+			LinkIndex: link.Attrs().Index,
+			Gw:        gw,
+		}
+
+		if err = netlink.RouteAddEcmp(&route); err != nil {
+			return fmt.Errorf("failed to add route '%v via %v dev %v': %v", r.Dst, gw, ifName, err)
 		}
 	}
 

plugins/main/bridge/bridge.go

@@ -122,7 +122,7 @@ func calcGateways(result *current.Result, n *NetConf) (*gwInfo, *gwInfo, error)
 
 		// Add a default route for this family using the current
 		// gateway address if necessary.
-		if n.IsDefaultGW && !gws.defaultRouteFound {
+		if n.IsDefaultGW {
 			for _, route := range result.Routes {
 				if route.GW != nil && defaultNet.String() == route.Dst.String() {
 					gws.defaultRouteFound = true