spec/plugins: return interface details and multiple IP addresses to runtime

Updates the spec and plugins to return an array of interfaces and IP details
to the runtime including:

- interface names and MAC addresses configured by the plugin
- whether the interfaces are sandboxed (container/VM) or host (bridge, veth, etc)
- multiple IP addresses configured by IPAM and which interface they
have been assigned to

Returning interface details is useful for runtimes, as well as allowing
more flexible chaining of CNI plugins themselves.  For example, some
meta plugins may need to know the host-side interface to be able to
apply firewall or traffic shaping rules to the container.

plugins/main/ipvlan/ipvlan.go

@@ -44,15 +44,15 @@ func init() {
 	runtime.LockOSThread()
 }
 
-func loadConf(bytes []byte) (*NetConf, error) {
+func loadConf(bytes []byte) (*NetConf, string, error) {
 	n := &NetConf{}
 	if err := json.Unmarshal(bytes, n); err != nil {
-		return nil, fmt.Errorf("failed to load netconf: %v", err)
+		return nil, "", fmt.Errorf("failed to load netconf: %v", err)
 	}
 	if n.Master == "" {
-		return nil, fmt.Errorf(`"master" field is required. It specifies the host interface name to virtualize`)
+		return nil, "", fmt.Errorf(`"master" field is required. It specifies the host interface name to virtualize`)
 	}
-	return n, nil
+	return n, n.CNIVersion, nil
 }
 
 func modeFromString(s string) (netlink.IPVlanMode, error) {
@@ -68,22 +68,24 @@ func modeFromString(s string) (netlink.IPVlanMode, error) {
 	}
 }
 
-func createIpvlan(conf *NetConf, ifName string, netns ns.NetNS) error {
+func createIpvlan(conf *NetConf, ifName string, netns ns.NetNS) (*current.Interface, error) {
+	ipvlan := &current.Interface{}
+
 	mode, err := modeFromString(conf.Mode)
 	if err != nil {
-		return err
+		return nil, err
 	}
 
 	m, err := netlink.LinkByName(conf.Master)
 	if err != nil {
-		return fmt.Errorf("failed to lookup master %q: %v", conf.Master, err)
+		return nil, fmt.Errorf("failed to lookup master %q: %v", conf.Master, err)
 	}
 
 	// due to kernel bug we have to create with tmpname or it might
 	// collide with the name on the host and error out
 	tmpName, err := ip.RandomVethName()
 	if err != nil {
-		return err
+		return nil, err
 	}
 
 	mv := &netlink.IPVlan{
@@ -97,20 +99,35 @@ func createIpvlan(conf *NetConf, ifName string, netns ns.NetNS) error {
 	}
 
 	if err := netlink.LinkAdd(mv); err != nil {
-		return fmt.Errorf("failed to create ipvlan: %v", err)
+		return nil, fmt.Errorf("failed to create ipvlan: %v", err)
 	}
 
-	return netns.Do(func(_ ns.NetNS) error {
+	err = netns.Do(func(_ ns.NetNS) error {
 		err := ip.RenameLink(tmpName, ifName)
 		if err != nil {
 			return fmt.Errorf("failed to rename ipvlan to %q: %v", ifName, err)
 		}
+		ipvlan.Name = ifName
+
+		// Re-fetch ipvlan to get all properties/attributes
+		contIpvlan, err := netlink.LinkByName(ipvlan.Name)
+		if err != nil {
+			return fmt.Errorf("failed to refetch ipvlan %q: %v", ipvlan.Name, err)
+		}
+		ipvlan.Mac = contIpvlan.Attrs().HardwareAddr.String()
+		ipvlan.Sandbox = netns.Path()
+
 		return nil
 	})
+	if err != nil {
+		return nil, err
+	}
+
+	return ipvlan, nil
 }
 
 func cmdAdd(args *skel.CmdArgs) error {
-	n, err := loadConf(args.StdinData)
+	n, cniVersion, err := loadConf(args.StdinData)
 	if err != nil {
 		return err
 	}
@@ -121,7 +138,8 @@ func cmdAdd(args *skel.CmdArgs) error {
 	}
 	defer netns.Close()
 
-	if err = createIpvlan(n, args.IfName, netns); err != nil {
+	ipvlanInterface, err := createIpvlan(n, args.IfName, netns)
+	if err != nil {
 		return err
 	}
 
@@ -130,14 +148,21 @@ func cmdAdd(args *skel.CmdArgs) error {
 	if err != nil {
 		return err
 	}
-	result, err := current.GetResult(r)
+	// Convert whatever the IPAM result was into the current Result type
+	result, err := current.NewResultFromResult(r)
 	if err != nil {
 		return err
 	}
 
-	if result.IP4 == nil {
-		return errors.New("IPAM plugin returned missing IPv4 config")
+	if len(result.IPs) == 0 {
+		return errors.New("IPAM plugin returned missing IP config")
 	}
+	for _, ipc := range result.IPs {
+		// All addresses belong to the ipvlan interface
+		ipc.Interface = 0
+	}
+
+	result.Interfaces = []*current.Interface{ipvlanInterface}
 
 	err = netns.Do(func(_ ns.NetNS) error {
 		return ipam.ConfigureIface(args.IfName, result)
@@ -147,11 +172,12 @@ func cmdAdd(args *skel.CmdArgs) error {
 	}
 
 	result.DNS = n.DNS
-	return result.Print()
+
+	return types.PrintResult(result, cniVersion)
 }
 
 func cmdDel(args *skel.CmdArgs) error {
-	n, err := loadConf(args.StdinData)
+	n, _, err := loadConf(args.StdinData)
 	if err != nil {
 		return err
 	}
@@ -171,5 +197,5 @@ func cmdDel(args *skel.CmdArgs) error {
 }
 
 func main() {
-	skel.PluginMain(cmdAdd, cmdDel, version.Legacy)
+	skel.PluginMain(cmdAdd, cmdDel, version.All)
 }