libnetwork/drivers/bridge: don't convert IP to string and back again

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

libnetwork/drivers/bridge/bridge.go

@@ -1373,9 +1373,7 @@ func (d *driver) link(network *bridgeNetwork, endpoint *bridgeEndpoint, enable b
 				return err
 			}
 
-			l := newLink(parentEndpoint.addr.IP.String(),
-				endpoint.addr.IP.String(),
-				ec.ExposedPorts, network.config.BridgeName)
+			l := newLink(parentEndpoint.addr.IP, endpoint.addr.IP, ec.ExposedPorts, network.config.BridgeName)
 			if enable {
 				err = l.Enable()
 				if err != nil {
@@ -1406,9 +1404,7 @@ func (d *driver) link(network *bridgeNetwork, endpoint *bridgeEndpoint, enable b
 			continue
 		}
 
-		l := newLink(endpoint.addr.IP.String(),
-			childEndpoint.addr.IP.String(),
-			childEndpoint.extConnConfig.ExposedPorts, network.config.BridgeName)
+		l := newLink(endpoint.addr.IP, childEndpoint.addr.IP, childEndpoint.extConnConfig.ExposedPorts, network.config.BridgeName)
 		if enable {
 			err = l.Enable()
 			if err != nil {

libnetwork/drivers/bridge/link.go

@@ -13,8 +13,8 @@ import (
 )
 
 type link struct {
-	parentIP string
-	childIP  string
+	parentIP net.IP
+	childIP  net.IP
 	ports    []types.TransportPort
 	bridge   string
 }
@@ -23,7 +23,7 @@ func (l *link) String() string {
 	return fmt.Sprintf("%s <-> %s [%v] on %s", l.parentIP, l.childIP, l.ports, l.bridge)
 }
 
-func newLink(parentIP, childIP string, ports []types.TransportPort, bridge string) *link {
+func newLink(parentIP, childIP net.IP, ports []types.TransportPort, bridge string) *link {
 	return &link{
 		childIP:  childIP,
 		parentIP: parentIP,
@@ -51,19 +51,17 @@ func (l *link) Disable() {
 	}
 }
 
-func linkContainers(action iptables.Action, parentIP, childIP string, ports []types.TransportPort, bridge string, ignoreErrors bool) error {
-	ip1 := net.ParseIP(parentIP)
-	if ip1 == nil {
-		return fmt.Errorf("cannot link to a container with an invalid parent IP address %q", parentIP)
+func linkContainers(action iptables.Action, parentIP, childIP net.IP, ports []types.TransportPort, bridge string, ignoreErrors bool) error {
+	if parentIP == nil {
+		return fmt.Errorf("cannot link to a container with an empty parent IP address")
 	}
-	ip2 := net.ParseIP(childIP)
-	if ip2 == nil {
-		return fmt.Errorf("cannot link to a container with an invalid child IP address %q", childIP)
+	if childIP == nil {
+		return fmt.Errorf("cannot link to a container with an empty child IP address")
 	}
 
 	chain := iptables.ChainInfo{Name: DockerChain}
 	for _, port := range ports {
-		err := chain.Link(action, ip1, ip2, int(port.Port), port.Proto.String(), bridge)
+		err := chain.Link(action, parentIP, childIP, int(port.Port), port.Proto.String(), bridge)
 		if !ignoreErrors && err != nil {
 			return err
 		}

libnetwork/drivers/bridge/link_test.go

@@ -3,6 +3,7 @@
 package bridge
 
 import (
+	"net"
 	"testing"
 
 	"github.com/docker/docker/libnetwork/types"
@@ -19,23 +20,31 @@ func getPorts() []types.TransportPort {
 func TestLinkNew(t *testing.T) {
 	ports := getPorts()
 
-	link := newLink("172.0.17.3", "172.0.17.2", ports, "docker0")
+	const (
+		pIP        = "172.0.17.3"
+		cIP        = "172.0.17.2"
+		bridgeName = "docker0"
+	)
 
-	if link == nil {
+	parentIP := net.ParseIP(pIP)
+	childIP := net.ParseIP(cIP)
+
+	l := newLink(parentIP, childIP, ports, bridgeName)
+	if l == nil {
 		t.FailNow()
 	}
-	if link.parentIP != "172.0.17.3" {
+	if l.parentIP.String() != pIP {
 		t.Fail()
 	}
-	if link.childIP != "172.0.17.2" {
+	if l.childIP.String() != cIP {
 		t.Fail()
 	}
-	for i, p := range link.ports {
+	for i, p := range l.ports {
 		if p != ports[i] {
 			t.Fail()
 		}
 	}
-	if link.bridge != "docker0" {
+	if l.bridge != bridgeName {
 		t.Fail()
 	}
 }