pkg/datapath/linux/route: ensure the package compiles on macOS

This package already has `route_darwin.go` and `route_linux.go`,
but some functions in `route.go` did not respected this.

Signed-off-by: Ilya Dmitrichenko <errordeveloper@gmail.com>

pkg/datapath/linux/route/route.go

@@ -19,7 +19,6 @@ import (
 	"net"
 
 	"github.com/cilium/cilium/pkg/logging/logfields"
-	"github.com/cilium/cilium/pkg/option"
 
 	"github.com/sirupsen/logrus"
 	"github.com/vishvananda/netlink"
@@ -80,55 +79,3 @@ func (r *Route) ToIPCommand(dev string) []string {
 	res = append(res, "dev", dev)
 	return res
 }
-
-func lookupDefaultRoute(family int) (netlink.Route, error) {
-	linkIndex := 0
-
-	routes, err := netlink.RouteListFiltered(family, &netlink.Route{Dst: nil}, netlink.RT_FILTER_DST)
-	if err != nil {
-		return netlink.Route{}, fmt.Errorf("Unable to list direct routes: %s", err)
-	}
-
-	if len(routes) == 0 {
-		return netlink.Route{}, fmt.Errorf("Default route not found for family %d", family)
-	}
-
-	for _, route := range routes {
-		if linkIndex != 0 && linkIndex != route.LinkIndex {
-			return netlink.Route{}, fmt.Errorf("Found default routes with different netdev ifindices: %v vs %v",
-				linkIndex, route.LinkIndex)
-		}
-		linkIndex = route.LinkIndex
-	}
-
-	log.Debugf("Found default route on node %v", routes[0])
-	return routes[0], nil
-}
-
-// NodeDeviceWithDefaultRoute returns the node's device which handles the
-// default route in the current namespace
-func NodeDeviceWithDefaultRoute() (netlink.Link, error) {
-	linkIndex := 0
-	if option.Config.EnableIPv4 {
-		route, err := lookupDefaultRoute(netlink.FAMILY_V4)
-		if err != nil {
-			return nil, err
-		}
-		linkIndex = route.LinkIndex
-	}
-	if option.Config.EnableIPv6 {
-		route, err := lookupDefaultRoute(netlink.FAMILY_V6)
-		if err != nil {
-			return nil, err
-		}
-		if linkIndex != 0 && linkIndex != route.LinkIndex {
-			return nil, fmt.Errorf("IPv4/IPv6 have different link indices")
-		}
-		linkIndex = route.LinkIndex
-	}
-	link, err := netlink.LinkByIndex(linkIndex)
-	if err != nil {
-		return nil, err
-	}
-	return link, nil
-}

pkg/datapath/linux/route/route_darwin.go

@@ -20,15 +20,25 @@ import (
 	"fmt"
 
 	"github.com/cilium/cilium/pkg/mtu"
+
+	"github.com/vishvananda/netlink"
 )
 
-// Replace adds or replaces the specified route if necessary. Does nothing
-// for Darwin-based builds.
+// errUnsupportedOp is a common error
+var errUnsupportedOp = fmt.Errorf("Route operations not supported on Darwin")
+
+// Replace is not supported on Darwin and will return an error at runtime.
 func Replace(route Route, mtuConfig mtu.Configuration) error {
-	return fmt.Errorf("Operation not supported ")
+	return errUnsupportedOp
 }
 
-// Delete removes a route. Does nothing for Darwin-based builds.
+// Delete is not supported on Darwin and will return an error at runtime.
 func Delete(route Route) error {
-	return fmt.Errorf("Operation not supported ")
+	return errUnsupportedOp
+}
+
+// NodeDeviceWithDefaultRoute is not supported on Darwin and will return
+// an error at runtime.
+func NodeDeviceWithDefaultRoute() (netlink.Link, error) {
+	return nil, errUnsupportedOp
 }

pkg/datapath/linux/route/route_linux.go

@@ -21,6 +21,8 @@ import (
 	"net"
 	"time"
 
+	"github.com/cilium/cilium/pkg/option"
+
 	"github.com/vishvananda/netlink"
 )
 
@@ -409,3 +411,55 @@ func deleteRule(spec Rule, family int) error {
 	rule.Family = family
 	return netlink.RuleDel(rule)
 }
+
+func lookupDefaultRoute(family int) (netlink.Route, error) {
+	linkIndex := 0
+
+	routes, err := netlink.RouteListFiltered(family, &netlink.Route{Dst: nil}, netlink.RT_FILTER_DST)
+	if err != nil {
+		return netlink.Route{}, fmt.Errorf("Unable to list direct routes: %s", err)
+	}
+
+	if len(routes) == 0 {
+		return netlink.Route{}, fmt.Errorf("Default route not found for family %d", family)
+	}
+
+	for _, route := range routes {
+		if linkIndex != 0 && linkIndex != route.LinkIndex {
+			return netlink.Route{}, fmt.Errorf("Found default routes with different netdev ifindices: %v vs %v",
+				linkIndex, route.LinkIndex)
+		}
+		linkIndex = route.LinkIndex
+	}
+
+	log.Debugf("Found default route on node %v", routes[0])
+	return routes[0], nil
+}
+
+// NodeDeviceWithDefaultRoute returns the node's device which handles the
+// default route in the current namespace
+func NodeDeviceWithDefaultRoute() (netlink.Link, error) {
+	linkIndex := 0
+	if option.Config.EnableIPv4 {
+		route, err := lookupDefaultRoute(netlink.FAMILY_V4)
+		if err != nil {
+			return nil, err
+		}
+		linkIndex = route.LinkIndex
+	}
+	if option.Config.EnableIPv6 {
+		route, err := lookupDefaultRoute(netlink.FAMILY_V6)
+		if err != nil {
+			return nil, err
+		}
+		if linkIndex != 0 && linkIndex != route.LinkIndex {
+			return nil, fmt.Errorf("IPv4/IPv6 have different link indices")
+		}
+		linkIndex = route.LinkIndex
+	}
+	link, err := netlink.LinkByIndex(linkIndex)
+	if err != nil {
+		return nil, err
+	}
+	return link, nil
+}