netlink: add default Route to NetworkGetRoutes

Docker-DCO-1.1-Signed-off-by: Johan Euphrosine <proppy@google.com> (github: proppy)

network.go

@@ -71,9 +71,9 @@ func networkSize(mask net.IPMask) int32 {
 	return int32(binary.BigEndian.Uint32(m)) + 1
 }
 
-func checkRouteOverlaps(networks []*net.IPNet, dockerNetwork *net.IPNet) error {
+func checkRouteOverlaps(networks []netlink.Route, dockerNetwork *net.IPNet) error {
 	for _, network := range networks {
-		if networkOverlaps(dockerNetwork, network) {
+		if networkOverlaps(dockerNetwork, network.IPNet) {
 			return fmt.Errorf("Network %s is already routed: '%s'", dockerNetwork, network)
 		}
 	}

network_test.go

@@ -2,7 +2,9 @@ package docker
 
 import (
 	"github.com/dotcloud/docker/pkg/iptables"
+	"github.com/dotcloud/docker/pkg/netlink"
 	"github.com/dotcloud/docker/proxy"
+
 	"net"
 	"testing"
 )
@@ -289,10 +291,10 @@ func TestNetworkOverlaps(t *testing.T) {
 func TestCheckRouteOverlaps(t *testing.T) {
 	routesData := []string{"10.0.2.0/32", "10.0.3.0/24", "10.0.42.0/24", "172.16.42.0/24", "192.168.142.0/24"}
 
-	routes := []*net.IPNet{}
+	routes := []netlink.Route{}
 	for _, addr := range routesData {
 		_, netX, _ := net.ParseCIDR(addr)
-		routes = append(routes, netX)
+		routes = append(routes, netlink.Route{IPNet: netX})
 	}
 
 	_, netX, _ := net.ParseCIDR("172.16.0.1/24")

pkg/netlink/netlink_linux.go

@@ -471,9 +471,16 @@ func NetworkLinkAdd(name string, linkType string) error {
 	return s.HandleAck(wb.Seq)
 }
 
+// A Route is a subnet associated with the interface to reach it.
+type Route struct {
+	*net.IPNet
+	Iface   *net.Interface
+	Default bool
+}
+
 // Returns an array of IPNet for all the currently routed subnets on ipv4
 // This is similar to the first column of "ip route" output
-func NetworkGetRoutes() ([]*net.IPNet, error) {
+func NetworkGetRoutes() ([]Route, error) {
 	native := nativeEndian()
 
 	s, err := getNetlinkSocket()
@@ -496,7 +503,7 @@ func NetworkGetRoutes() ([]*net.IPNet, error) {
 		return nil, err
 	}
 
-	res := make([]*net.IPNet, 0)
+	res := make([]Route, 0)
 
 done:
 	for {
@@ -525,8 +532,7 @@ done:
 				continue
 			}
 
-			var iface *net.Interface = nil
-			var ipNet *net.IPNet = nil
+			var r Route
 
 			msg := (*RtMsg)(unsafe.Pointer(&m.Data[0:syscall.SizeofRtMsg][0]))
 
@@ -546,8 +552,8 @@ done:
 			}
 
 			if msg.Dst_len == 0 {
-				// Ignore default routes
-				continue
+				// Default routes
+				r.Default = true
 			}
 
 			attrs, err := syscall.ParseNetlinkRouteAttr(&m)
@@ -558,18 +564,17 @@ done:
 				switch attr.Attr.Type {
 				case syscall.RTA_DST:
 					ip := attr.Value
-					ipNet = &net.IPNet{
+					r.IPNet = &net.IPNet{
 						IP:   ip,
 						Mask: net.CIDRMask(int(msg.Dst_len), 8*len(ip)),
 					}
 				case syscall.RTA_OIF:
 					index := int(native.Uint32(attr.Value[0:4]))
-					iface, _ = net.InterfaceByIndex(index)
-					_ = iface
+					r.Iface, _ = net.InterfaceByIndex(index)
 				}
 			}
-			if ipNet != nil {
-				res = append(res, ipNet)
+			if r.Default || r.IPNet != nil {
+				res = append(res, r)
 			}
 		}
 	}