network: Stop shelling out to /sbin/ip

We have our own netlink version of all the required calls now, so
we can just skip the /sbin/ip dependency.

network.go

@@ -6,12 +6,11 @@ import (
 	"fmt"
 	"github.com/dotcloud/docker/iptables"
 	"github.com/dotcloud/docker/proxy"
+	"github.com/dotcloud/docker/netlink"
 	"github.com/dotcloud/docker/utils"
 	"log"
 	"net"
-	"os/exec"
 	"strconv"
-	"strings"
 	"sync"
 )
 
@@ -68,42 +67,10 @@ func networkSize(mask net.IPMask) int32 {
 	return int32(binary.BigEndian.Uint32(m)) + 1
 }
 
-//Wrapper around the ip command
-func ip(args ...string) (string, error) {
-	path, err := exec.LookPath("ip")
-	if err != nil {
-		return "", fmt.Errorf("command not found: ip")
-	}
-	output, err := exec.Command(path, args...).CombinedOutput()
-	if err != nil {
-		return "", fmt.Errorf("ip failed: ip %v", strings.Join(args, " "))
-	}
-	return string(output), nil
-}
-
-func checkRouteOverlaps(routes string, dockerNetwork *net.IPNet) error {
-	utils.Debugf("Routes:\n\n%s", routes)
-	for _, line := range strings.Split(routes, "\n") {
-		if strings.Trim(line, "\r\n\t ") == "" || strings.Contains(line, "default") {
-			continue
-		}
-		_, network, err := net.ParseCIDR(strings.Split(line, " ")[0])
-		if err != nil {
-			// is this a mask-less IP address?
-			if ip := net.ParseIP(strings.Split(line, " ")[0]); ip == nil {
-				// fail only if it's neither a network nor a mask-less IP address
-				return fmt.Errorf("Unexpected ip route output: %s (%s)", err, line)
-			} else {
-				_, network, err = net.ParseCIDR(ip.String() + "/32")
-				if err != nil {
-					return err
-				}
-			}
-		}
-		if err == nil && network != nil {
-			if networkOverlaps(dockerNetwork, network) {
-				return fmt.Errorf("Network %s is already routed: '%s'", dockerNetwork, line)
-			}
+func checkRouteOverlaps(networks []*net.IPNet, dockerNetwork *net.IPNet) error {
+	for _, network := range networks {
+		if networkOverlaps(dockerNetwork, network) {
+			return fmt.Errorf("Network %s is already routed: '%s'", dockerNetwork, network)
 		}
 	}
 	return nil
@@ -139,7 +106,7 @@ func CreateBridgeIface(config *DaemonConfig) error {
 		if err != nil {
 			return err
 		}
-		routes, err := ip("route")
+		routes, err := netlink.NetworkGetRoutes()
 		if err != nil {
 			return err
 		}
@@ -155,15 +122,22 @@ func CreateBridgeIface(config *DaemonConfig) error {
 	}
 	utils.Debugf("Creating bridge %s with network %s", config.BridgeIface, ifaceAddr)
 
-	if output, err := ip("link", "add", config.BridgeIface, "type", "bridge"); err != nil {
-		return fmt.Errorf("Error creating bridge: %s (output: %s)", err, output)
+	if err := netlink.NetworkLinkAdd(config.BridgeIface, "bridge"); err != nil {
+		return fmt.Errorf("Error creating bridge: %s", err)
 	}
-
-	if output, err := ip("addr", "add", ifaceAddr, "dev", config.BridgeIface); err != nil {
-		return fmt.Errorf("Unable to add private network: %s (%s)", err, output)
+	iface, err := net.InterfaceByName(config.BridgeIface)
+	if err != nil {
+		return err
 	}
-	if output, err := ip("link", "set", config.BridgeIface, "up"); err != nil {
-		return fmt.Errorf("Unable to start network bridge: %s (%s)", err, output)
+	ipAddr, ipNet, err := net.ParseCIDR(ifaceAddr)
+	if err != nil {
+		return err
+	}
+	if netlink.NetworkLinkAddIp(iface, ipAddr, ipNet); err != nil {
+		return fmt.Errorf("Unable to add private network: %s", err)
+	}
+	if err := netlink.NetworkLinkUp(iface); err != nil {
+		return fmt.Errorf("Unable to start network bridge: %s", err)
 	}
 
 	if config.EnableIptables {

network_test.go

@@ -277,12 +277,13 @@ func TestNetworkOverlaps(t *testing.T) {
 }
 
 func TestCheckRouteOverlaps(t *testing.T) {
-	routes := `default via 10.0.2.2 dev eth0
-10.0.2.0 dev eth0  proto kernel  scope link  src 10.0.2.15
-10.0.3.0/24 dev lxcbr0  proto kernel  scope link  src 10.0.3.1
-10.0.42.0/24 dev testdockbr0  proto kernel  scope link  src 10.0.42.1
-172.16.42.0/24 dev docker0  proto kernel  scope link  src 172.16.42.1
-192.168.142.0/24 dev eth1  proto kernel  scope link  src 192.168.142.142`
+	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{}
+	for _, addr := range routesData {
+		_, netX, _ := net.ParseCIDR(addr)
+		routes = append(routes, netX)
+	}
 
 	_, netX, _ := net.ParseCIDR("172.16.0.1/24")
 	if err := checkRouteOverlaps(routes, netX); err != nil {