Refactor network creation and initialization into strategies

Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)

libcontainer/network/veth.go

@@ -0,0 +1,103 @@
+package network
+
+import (
+	"fmt"
+	"github.com/dotcloud/docker/pkg/libcontainer"
+	"github.com/dotcloud/docker/pkg/libcontainer/utils"
+	"log"
+)
+
+type Veth struct {
+}
+
+func (v *Veth) Create(n *libcontainer.Network, nspid int) (libcontainer.Context, error) {
+	log.Printf("creating veth network")
+	var (
+		bridge string
+		prefix string
+		exists bool
+	)
+	if bridge, exists = n.Context["bridge"]; !exists {
+		return nil, fmt.Errorf("bridge does not exist in network context")
+	}
+	if prefix, exists = n.Context["prefix"]; !exists {
+		return nil, fmt.Errorf("veth prefix does not exist in network context")
+	}
+	name1, name2, err := createVethPair(prefix)
+	if err != nil {
+		return nil, err
+	}
+	context := libcontainer.Context{
+		"vethHost":  name1,
+		"vethChild": name2,
+	}
+	log.Printf("veth pair created %s <> %s", name1, name2)
+	if err := SetInterfaceMaster(name1, bridge); err != nil {
+		return context, err
+	}
+	if err := SetMtu(name1, n.Mtu); err != nil {
+		return context, err
+	}
+	if err := InterfaceUp(name1); err != nil {
+		return context, err
+	}
+	log.Printf("setting %s inside %d namespace", name2, nspid)
+	if err := SetInterfaceInNamespacePid(name2, nspid); err != nil {
+		return context, err
+	}
+	return context, nil
+}
+
+func (v *Veth) Initialize(config *libcontainer.Network, context libcontainer.Context) error {
+	var (
+		vethChild string
+		exists    bool
+	)
+	if vethChild, exists = context["vethChild"]; !exists {
+		return fmt.Errorf("vethChild does not exist in network context")
+	}
+	if err := InterfaceDown(vethChild); err != nil {
+		return fmt.Errorf("interface down %s %s", vethChild, err)
+	}
+	if err := ChangeInterfaceName(vethChild, "eth0"); err != nil {
+		return fmt.Errorf("change %s to eth0 %s", vethChild, err)
+	}
+	if err := SetInterfaceIp("eth0", config.Address); err != nil {
+		return fmt.Errorf("set eth0 ip %s", err)
+	}
+	if err := SetMtu("eth0", config.Mtu); err != nil {
+		return fmt.Errorf("set eth0 mtu to %d %s", config.Mtu, err)
+	}
+	if err := InterfaceUp("eth0"); err != nil {
+		return fmt.Errorf("eth0 up %s", err)
+	}
+	if err := SetMtu("lo", config.Mtu); err != nil {
+		return fmt.Errorf("set lo mtu to %d %s", config.Mtu, err)
+	}
+	if err := InterfaceUp("lo"); err != nil {
+		return fmt.Errorf("lo up %s", err)
+	}
+	if config.Gateway != "" {
+		if err := SetDefaultGateway(config.Gateway); err != nil {
+			return fmt.Errorf("set gateway to %s %s", config.Gateway, err)
+		}
+	}
+	return nil
+}
+
+// createVethPair will automatically generage two random names for
+// the veth pair and ensure that they have been created
+func createVethPair(prefix string) (name1 string, name2 string, err error) {
+	name1, err = utils.GenerateRandomName(prefix, 4)
+	if err != nil {
+		return
+	}
+	name2, err = utils.GenerateRandomName(prefix, 4)
+	if err != nil {
+		return
+	}
+	if err = CreateVethPair(name1, name2); err != nil {
+		return
+	}
+	return
+}