Make network a slice to support multiple types

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

libcontainer/README.md

@@ -48,7 +48,7 @@ Sample `container.json` file:
         "MAC_ADMIN",
         "NET_ADMIN"
     ],
-    "network": {
+    "networks": [{
             "type": "veth",
             "context": {
                 "bridge": "docker0",
@@ -57,7 +57,8 @@ Sample `container.json` file:
             "address": "172.17.0.100/16",
             "gateway": "172.17.42.1",
             "mtu": 1500
-    },
+        }
+    ],
     "cgroups": {
         "name": "docker-koye",
         "parent": "docker",

libcontainer/container.go

@@ -19,7 +19,7 @@ type Container struct {
 	Tty          bool            `json:"tty,omitempty"`          // setup a proper tty or not
 	Namespaces   Namespaces      `json:"namespaces,omitempty"`   // namespaces to apply
 	Capabilities Capabilities    `json:"capabilities,omitempty"` // capabilities to drop
-	Network      *Network        `json:"network,omitempty"`      // nil for host's network stack
+	Networks     []*Network      `json:"networks,omitempty"`     // nil for host's network stack
 	Cgroups      *cgroups.Cgroup `json:"cgroups,omitempty"`
 }
 

libcontainer/container.json

@@ -31,7 +31,7 @@
         "MAC_ADMIN",
         "NET_ADMIN"
     ],
-    "network": {
+    "networks": [{
             "type": "veth",
             "context": {
                 "bridge": "docker0",
@@ -40,7 +40,8 @@
             "address": "172.17.0.100/16",
             "gateway": "172.17.42.1",
             "mtu": 1500
-    },
+        }
+    ],
     "cgroups": {
         "name": "docker-koye",
         "parent": "docker",

libcontainer/network/strategy.go

@@ -16,7 +16,7 @@ var strategies = map[string]NetworkStrategy{
 // NetworkStrategy represends a specific network configuration for
 // a containers networking stack
 type NetworkStrategy interface {
-	Create(*libcontainer.Network, int) (libcontainer.Context, error)
+	Create(*libcontainer.Network, int, libcontainer.Context) error
 	Initialize(*libcontainer.Network, libcontainer.Context) error
 }
 

libcontainer/network/veth.go

@@ -12,39 +12,37 @@ import (
 type Veth struct {
 }
 
-func (v *Veth) Create(n *libcontainer.Network, nspid int) (libcontainer.Context, error) {
+func (v *Veth) Create(n *libcontainer.Network, nspid int, context libcontainer.Context) error {
 	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")
+		return 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")
+		return fmt.Errorf("veth prefix does not exist in network context")
 	}
 	name1, name2, err := createVethPair(prefix)
 	if err != nil {
-		return nil, err
+		return err
-	}
-	context := libcontainer.Context{
-		"vethHost":  name1,
-		"vethChild": name2,
 	}
+	context["veth-host"] = name1
+	context["veth-child"] = name2
 	if err := SetInterfaceMaster(name1, bridge); err != nil {
-		return context, err
+		return err
 	}
 	if err := SetMtu(name1, n.Mtu); err != nil {
-		return context, err
+		return err
 	}
 	if err := InterfaceUp(name1); err != nil {
-		return context, err
+		return err
 	}
 	if err := SetInterfaceInNamespacePid(name2, nspid); err != nil {
-		return context, err
+		return err
 	}
-	return context, nil
+	return nil
 }
 
 func (v *Veth) Initialize(config *libcontainer.Network, context libcontainer.Context) error {
@@ -52,7 +50,7 @@ func (v *Veth) Initialize(config *libcontainer.Network, context libcontainer.Con
 		vethChild string
 		exists    bool
 	)
-	if vethChild, exists = context["vethChild"]; !exists {
+	if vethChild, exists = context["veth-child"]; !exists {
 		return fmt.Errorf("vethChild does not exist in network context")
 	}
 	if err := InterfaceDown(vethChild); err != nil {

libcontainer/nsinit/exec.go

@@ -84,18 +84,15 @@ func (ns *linuxNs) SetupCgroups(container *libcontainer.Container, nspid int) er
 }
 
 func (ns *linuxNs) InitializeNetworking(container *libcontainer.Container, nspid int, pipe *SyncPipe) error {
-	if container.Network != nil {
+	context := libcontainer.Context{}
-		strategy, err := network.GetStrategy(container.Network.Type)
+	for _, config := range container.Networks {
+		strategy, err := network.GetStrategy(config.Type)
 		if err != nil {
 			return err
 		}
-		networkContext, err := strategy.Create(container.Network, nspid)
+		if err := strategy.Create(config, nspid, context); err != nil {
-		if err != nil {
-			return err
-		}
-		if err := pipe.SendToChild(networkContext); err != nil {
 			return err
 		}
 	}
-	return nil
+	return pipe.SendToChild(context)
 }

libcontainer/nsinit/init.go

@@ -56,7 +56,7 @@ func (ns *linuxNs) Init(container *libcontainer.Container, uncleanRootfs, consol
 	if err := setupNewMountNamespace(rootfs, console, container.ReadonlyFs); err != nil {
 		return fmt.Errorf("setup mount namespace %s", err)
 	}
-	if err := setupNetwork(container.Network, context); err != nil {
+	if err := setupNetwork(container, context); err != nil {
 		return fmt.Errorf("setup networking %s", err)
 	}
 	if err := system.Sethostname(container.Hostname); err != nil {
@@ -130,8 +130,8 @@ func dupSlave(slave *os.File) error {
 // setupVethNetwork uses the Network config if it is not nil to initialize
 // the new veth interface inside the container for use by changing the name to eth0
 // setting the MTU and IP address along with the default gateway
-func setupNetwork(config *libcontainer.Network, context libcontainer.Context) error {
+func setupNetwork(container *libcontainer.Container, context libcontainer.Context) error {
-	if config != nil {
+	for _, config := range container.Networks {
 		strategy, err := network.GetStrategy(config.Type)
 		if err != nil {
 			return err