Merge pull request #93 from squeed/host-device

plugins/main/host-device: generate result, fix DEL, other cleanups

plugins/main/host-device/README.md

@@ -0,0 +1,21 @@
+# host-device
+Move an already-existing device in to a container.
+
+This simple plugin will move the requested device from the host's network namespace
+to the container's. Nothing else will be done - no IPAM, no addresses.
+
+The device can be specified with any one of three properties:
+* `device`: The device name, e.g. `eth0`, `can0`
+* `hwaddr`: A MAC address
+* `kernelpath`: The kernel device kobj, e.g. `/sys/devices/pci0000:00/0000:00:1f.6`
+
+For this plugin, `CNI_IFNAME` will be ignored. Upon DEL, the device will be moved back.
+
+A sample configuration might look like:
+
+```json
+{
+	"cniVersion": "0.3.1",
+	"device": "enp0s1"
+}
+```

plugins/main/host-device/host-device.go

@@ -25,6 +25,7 @@ import (
 	"strings"
 
 	"github.com/containernetworking/cni/pkg/skel"
+	"github.com/containernetworking/cni/pkg/types"
 	"github.com/containernetworking/cni/pkg/types/current"
 	"github.com/containernetworking/cni/pkg/version"
 	"github.com/containernetworking/plugins/pkg/ns"
@@ -32,6 +33,7 @@ import (
 )
 
 type NetConf struct {
+	types.NetConf
 	Device     string `json:"device"`     // Device-Name, something like eth0 or can0 etc.
 	HWAddr     string `json:"hwaddr"`     // MAC Address of target network interface
 	KernelPath string `json:"kernelpath"` // Kernelpath of the device
@@ -65,8 +67,12 @@ func cmdAdd(args *skel.CmdArgs) error {
 		return fmt.Errorf("failed to open netns %q: %v", args.Netns, err)
 	}
 	defer containerNs.Close()
-	defer (&current.Result{}).Print()
+
-	return addLink(cfg.Device, cfg.HWAddr, cfg.KernelPath, containerNs)
+	dev, err := moveLinkIn(cfg.Device, cfg.HWAddr, cfg.KernelPath, containerNs)
+	if err != nil {
+		return fmt.Errorf("failed to move link %v", err)
+	}
+	return printLink(dev, cfg.CNIVersion, containerNs)
 }
 
 func cmdDel(args *skel.CmdArgs) error {
@@ -80,35 +86,58 @@ func cmdDel(args *skel.CmdArgs) error {
 	}
 	defer containerNs.Close()
 	defer fmt.Println(`{}`)
-	return removeLink(cfg.Device, cfg.HWAddr, cfg.KernelPath, containerNs)
+	return moveLinkOut(cfg.Device, cfg.HWAddr, cfg.KernelPath, containerNs)
 }
 
-func addLink(device, hwAddr, kernelPath string, containerNs ns.NetNS) error {
+func moveLinkIn(device, hwAddr, kernelPath string, containerNs ns.NetNS) (netlink.Link, error) {
 	dev, err := getLink(device, hwAddr, kernelPath)
 	if err != nil {
-		return err
+		return nil, err
+	}
+	if err := netlink.LinkSetNsFd(dev, int(containerNs.Fd())); err != nil {
+		return nil, err
 	}
-	return netlink.LinkSetNsFd(dev, int(containerNs.Fd()))
-}
 
-func removeLink(device, hwAddr, kernelPath string, containerNs ns.NetNS) error {
+	if err := containerNs.Do(func(_ ns.NetNS) error {
-	var dev netlink.Link
+		dev, err = netlink.LinkByName(dev.Attrs().Name)
-	err := containerNs.Do(func(_ ns.NetNS) error {
-		d, err := getLink(device, hwAddr, kernelPath)
 		if err != nil {
 			return err
 		}
-		dev = d
 		return nil
-	})
+	}); err != nil {
-	if err != nil {
+		return nil, err
-		return err
 	}
+
+	return dev, nil
+}
+
+func moveLinkOut(device, hwAddr, kernelPath string, containerNs ns.NetNS) error {
 	defaultNs, err := ns.GetCurrentNS()
 	if err != nil {
 		return err
 	}
-	return netlink.LinkSetNsFd(dev, int(defaultNs.Fd()))
+
+	return containerNs.Do(func(_ ns.NetNS) error {
+		dev, err := getLink(device, hwAddr, kernelPath)
+		if err != nil {
+			return err
+		}
+		return netlink.LinkSetNsFd(dev, int(defaultNs.Fd()))
+	})
+}
+
+func printLink(dev netlink.Link, cniVersion string, containerNs ns.NetNS) error {
+	result := current.Result{
+		CNIVersion: current.ImplementedSpecVersion,
+		Interfaces: []*current.Interface{
+			{
+				Name:    dev.Attrs().Name,
+				Mac:     dev.Attrs().HardwareAddr.String(),
+				Sandbox: containerNs.Path(),
+			},
+		},
+	}
+	return types.PrintResult(&result, cniVersion)
 }
 
 func getLink(devname, hwaddr, kernelpath string) (netlink.Link, error) {

plugins/main/host-device/host-device_test.go

@@ -19,6 +19,8 @@ import (
 	"math/rand"
 
 	"github.com/containernetworking/cni/pkg/skel"
+	"github.com/containernetworking/cni/pkg/types"
+	"github.com/containernetworking/cni/pkg/types/current"
 	"github.com/containernetworking/plugins/pkg/ns"
 	"github.com/containernetworking/plugins/pkg/testutils"
 	. "github.com/onsi/ginkgo"
@@ -44,6 +46,8 @@ var _ = Describe("base functionality", func() {
 
 	It("Works with a valid config", func() {
 
+		var origLink netlink.Link
+
 		// prepare ifname in original namespace
 		err := originalNS.Do(func(ns.NetNS) error {
 			defer GinkgoRecover()
@@ -53,9 +57,9 @@ var _ = Describe("base functionality", func() {
 				},
 			})
 			Expect(err).NotTo(HaveOccurred())
-			link, err := netlink.LinkByName(ifname)
+			origLink, err = netlink.LinkByName(ifname)
 			Expect(err).NotTo(HaveOccurred())
-			err = netlink.LinkSetUp(link)
+			err = netlink.LinkSetUp(origLink)
 			Expect(err).NotTo(HaveOccurred())
 			return nil
 		})
@@ -77,13 +81,26 @@ var _ = Describe("base functionality", func() {
 			IfName:      ifname,
 			StdinData:   []byte(conf),
 		}
+		var resI types.Result
 		err = originalNS.Do(func(ns.NetNS) error {
 			defer GinkgoRecover()
-			_, _, err := testutils.CmdAddWithResult(targetNS.Path(), ifname, []byte(conf), func() error { return cmdAdd(args) })
+			var err error
+			resI, _, err = testutils.CmdAddWithResult(targetNS.Path(), ifname, []byte(conf), func() error { return cmdAdd(args) })
 			return err
 		})
 		Expect(err).NotTo(HaveOccurred())
 
+		// check that the result was sane
+		res, err := current.NewResultFromResult(resI)
+		Expect(err).NotTo(HaveOccurred())
+		Expect(res.Interfaces).To(Equal([]*current.Interface{
+			{
+				Name:    ifname,
+				Mac:     origLink.Attrs().HardwareAddr.String(),
+				Sandbox: targetNS.Path(),
+			},
+		}))
+
 		// assert that dummy0 is now in the target namespace
 		err = targetNS.Do(func(ns.NetNS) error {
 			defer GinkgoRecover()
@@ -102,6 +119,19 @@ var _ = Describe("base functionality", func() {
 			return nil
 		})
 		Expect(err).NotTo(HaveOccurred())
+
+		// Check that deleting the device moves it back
+		err = originalNS.Do(func(ns.NetNS) error {
+			defer GinkgoRecover()
+			err = testutils.CmdDelWithResult(targetNS.Path(), ifname, func() error { return cmdDel(args) })
+			Expect(err).NotTo(HaveOccurred())
+
+			_, err := netlink.LinkByName(ifname)
+			Expect(err).NotTo(HaveOccurred())
+			return nil
+		})
+		Expect(err).NotTo(HaveOccurred())
+
 	})
 
 	It("fails an invalid config", func() {