fix duplicated default routes on Linux

Author: paulyufan2

cni/network/invoker_cns.go

@@ -488,16 +488,13 @@ func configureSecondaryAddResult(info *IPResultInfo, addResult *IPAMAddResult, p
 		return err
 	}
 
-	defaultRouteDstPrefix := network.Ipv4DefaultRouteDstPrefix
-	ncgw := net.ParseIP(info.ncGatewayIPAddress)
-
 	resRoute := addResult.interfaceInfo[key].Routes
 	if len(routes) > 0 {
 		resRoute = append(resRoute, routes...)
 	} else { // add default route to customer vnet on swiftv2 windows
 		resRoute = append(resRoute, network.RouteInfo{
-			Dst: defaultRouteDstPrefix,
-			Gw:  ncgw,
+			Dst: network.Ipv4DefaultRouteDstPrefix,
+			Gw:  net.ParseIP(info.ncGatewayIPAddress),
 		})
 	}
 

network/transparent_endpointclient_linux.go

@@ -233,7 +233,7 @@ func (client *TransparentEndpointClient) ConfigureContainerInterfacesAndRoutes(e
 
 	// add route for virtualgwip
 	// ip route add 169.254.1.1/32 dev eth0
-	virtualGwIP, virtualGwNet, _ := net.ParseCIDR(virtualGwIPString)
+	_, virtualGwNet, _ := net.ParseCIDR(virtualGwIPString)
 	routeInfo := RouteInfo{
 		Dst:   *virtualGwNet,
 		Scope: netlink.RT_SCOPE_LINK,
@@ -242,18 +242,7 @@ func (client *TransparentEndpointClient) ConfigureContainerInterfacesAndRoutes(e
 		return newErrorTransparentEndpointClient(err)
 	}
 
-	if !epInfo.SkipDefaultRoutes {
-		// ip route add default via 169.254.1.1 dev eth0
-		_, defaultIPNet, _ := net.ParseCIDR(defaultGwCidr)
-		dstIP := net.IPNet{IP: net.ParseIP(defaultGw), Mask: defaultIPNet.Mask}
-		routeInfo = RouteInfo{
-			Dst: dstIP,
-			Gw:  virtualGwIP,
-		}
-		if err := addRoutes(client.netlink, client.netioshim, client.containerVethName, []RouteInfo{routeInfo}); err != nil {
-			return err
-		}
-	} else if err := addRoutes(client.netlink, client.netioshim, client.containerVethName, epInfo.Routes); err != nil {
+	if err := addRoutes(client.netlink, client.netioshim, client.containerVethName, epInfo.Routes); err != nil {
 		return newErrorTransparentEndpointClient(err)
 	}