Merge pull request #3 from trusch/master

added host-device plugin which adds a specified link to container

plugins/host-device/host-device.go

@@ -0,0 +1,158 @@
+// Copyright 2015 CNI authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package main
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"io/ioutil"
+	"net"
+	"path/filepath"
+	"runtime"
+	"strings"
+
+	"github.com/containernetworking/cni/pkg/ns"
+	"github.com/containernetworking/cni/pkg/skel"
+	"github.com/containernetworking/cni/pkg/version"
+	"github.com/vishvananda/netlink"
+)
+
+type NetConf struct {
+	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
+}
+
+func init() {
+	// this ensures that main runs only on main thread (thread group leader).
+	// since namespace ops (unshare, setns) are done for a single thread, we
+	// must ensure that the goroutine does not jump from OS thread to thread
+	runtime.LockOSThread()
+}
+
+func loadConf(bytes []byte) (*NetConf, error) {
+	n := &NetConf{}
+	if err := json.Unmarshal(bytes, n); err != nil {
+		return nil, fmt.Errorf("failed to load netconf: %v", err)
+	}
+	if n.Device == "" && n.HWAddr == "" && n.KernelPath == "" {
+		return nil, fmt.Errorf(`specify either "device", "hwaddr" or "kernelpath"`)
+	}
+	return n, nil
+}
+
+func cmdAdd(args *skel.CmdArgs) error {
+	cfg, err := loadConf(args.StdinData)
+	if err != nil {
+		return err
+	}
+	containerNs, err := ns.GetNS(args.Netns)
+	if err != nil {
+		return fmt.Errorf("failed to open netns %q: %v", args.Netns, err)
+	}
+	defer containerNs.Close()
+	return addLink(cfg.Device, cfg.HWAddr, cfg.KernelPath, containerNs)
+}
+
+func cmdDel(args *skel.CmdArgs) error {
+	cfg, err := loadConf(args.StdinData)
+	if err != nil {
+		return err
+	}
+	containerNs, err := ns.GetNS(args.Netns)
+	if err != nil {
+		return fmt.Errorf("failed to open netns %q: %v", args.Netns, err)
+	}
+	defer containerNs.Close()
+	return removeLink(cfg.Device, cfg.HWAddr, cfg.KernelPath, containerNs)
+}
+
+func addLink(device, hwAddr, kernelPath string, containerNs ns.NetNS) error {
+	dev, err := getLink(device, hwAddr, kernelPath)
+	if err != nil {
+		return err
+	}
+	return netlink.LinkSetNsFd(dev, int(containerNs.Fd()))
+}
+
+func removeLink(device, hwAddr, kernelPath string, containerNs ns.NetNS) error {
+	var dev netlink.Link
+	err := containerNs.Do(func(_ ns.NetNS) error {
+		d, err := getLink(device, hwAddr, kernelPath)
+		if err != nil {
+			return err
+		}
+		dev = d
+		return nil
+	})
+	if err != nil {
+		return err
+	}
+	defaultNs, err := ns.GetCurrentNS()
+	if err != nil {
+		return err
+	}
+	return netlink.LinkSetNsFd(dev, int(defaultNs.Fd()))
+}
+
+func getLink(devname, hwaddr, kernelpath string) (netlink.Link, error) {
+	links, err := netlink.LinkList()
+	if err != nil {
+		return nil, fmt.Errorf("failed to list node links: %v", err)
+	}
+
+	if len(devname) > 0 {
+		if m, err := netlink.LinkByName(devname); err == nil {
+			return m, nil
+		}
+	} else if len(hwaddr) > 0 {
+		hwAddr, err := net.ParseMAC(hwaddr)
+		if err != nil {
+			return nil, fmt.Errorf("failed to parse MAC address %q: %v", hwaddr, err)
+		}
+
+		for _, link := range links {
+			if bytes.Equal(link.Attrs().HardwareAddr, hwAddr) {
+				return link, nil
+			}
+		}
+	} else if len(kernelpath) > 0 {
+		if !filepath.IsAbs(kernelpath) || !strings.HasPrefix(kernelpath, "/sys/devices/") {
+			return nil, fmt.Errorf("kernel device path %q must be absolute and begin with /sys/devices/", kernelpath)
+		}
+		netDir := filepath.Join(kernelpath, "net")
+		files, err := ioutil.ReadDir(netDir)
+		if err != nil {
+			return nil, fmt.Errorf("failed to find network devices at %q", netDir)
+		}
+
+		// Grab the first device from eg /sys/devices/pci0000:00/0000:00:19.0/net
+		for _, file := range files {
+			// Make sure it's really an interface
+			for _, l := range links {
+				if file.Name() == l.Attrs().Name {
+					return l, nil
+				}
+			}
+		}
+	}
+
+	return nil, fmt.Errorf("failed to find physical interface")
+}
+
+func main() {
+	skel.PluginMain(cmdAdd, cmdDel, version.All)
+}

plugins/host-device/host-device_suite_test.go

@@ -0,0 +1,27 @@
+// Copyright 2016 CNI authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package main
+
+import (
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+
+	"testing"
+)
+
+func TestVlan(t *testing.T) {
+	RegisterFailHandler(Fail)
+	RunSpecs(t, "host-device Suite")
+}

plugins/host-device/host-device_test.go

@@ -0,0 +1,117 @@
+// Copyright 2017 CNI authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package main
+
+import (
+	"github.com/containernetworking/cni/pkg/ns"
+	"github.com/containernetworking/cni/pkg/skel"
+	"github.com/containernetworking/cni/pkg/testutils"
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+	"github.com/vishvananda/netlink"
+)
+
+var ifname = "dummy0"
+
+var _ = Describe("base functionality", func() {
+	var originalNS ns.NetNS
+
+	BeforeEach(func() {
+		var err error
+		originalNS, err = ns.NewNS()
+		Expect(err).NotTo(HaveOccurred())
+	})
+
+	AfterEach(func() {
+		originalNS.Close()
+	})
+
+	It("Works with a valid config", func() {
+
+		// prepare ifname in original namespace
+		err := originalNS.Do(func(ns.NetNS) error {
+			defer GinkgoRecover()
+			err := netlink.LinkAdd(&netlink.Dummy{
+				LinkAttrs: netlink.LinkAttrs{
+					Name: ifname,
+				},
+			})
+			Expect(err).NotTo(HaveOccurred())
+			link, err := netlink.LinkByName(ifname)
+			Expect(err).NotTo(HaveOccurred())
+			err = netlink.LinkSetUp(link)
+			Expect(err).NotTo(HaveOccurred())
+			return nil
+		})
+		Expect(err).NotTo(HaveOccurred())
+
+		// call CmdAdd
+		targetNS, err := ns.NewNS()
+		Expect(err).NotTo(HaveOccurred())
+
+		conf := `{
+			"cniVersion": "0.3.0",
+			"name": "cni-plugin-host-device-test",
+			"type": "host-device",
+			"device": ifname
+		}`
+		args := &skel.CmdArgs{
+			ContainerID: "dummy",
+			Netns:       targetNS.Path(),
+			IfName:      ifname,
+			StdinData:   []byte(conf),
+		}
+		_, _, err = testutils.CmdAddWithResult(targetNS.Path(), ifname, []byte(conf), func() error { return cmdAdd(args) })
+		Expect(err).NotTo(HaveOccurred())
+
+		// assert that dummy0 is now in the target namespace
+		err = targetNS.Do(func(ns.NetNS) error {
+			defer GinkgoRecover()
+			link, err := netlink.LinkByName(ifname)
+			Expect(err).NotTo(HaveOccurred())
+			Expect(link.Attrs().Name).To(Equal(ifname))
+			return nil
+		})
+		Expect(err).NotTo(HaveOccurred())
+
+		// assert that dummy0 is now NOT in the original namespace anymore
+		err = originalNS.Do(func(ns.NetNS) error {
+			defer GinkgoRecover()
+			_, err := netlink.LinkByName(ifname)
+			Expect(err).To(HaveOccurred())
+			return nil
+		})
+		Expect(err).NotTo(HaveOccurred())
+	})
+
+	It("fails an invalid config", func() {
+		conf := `{
+			"cniVersion": "0.3.0",
+			"name": "cni-plugin-host-device-test",
+			"type": "host-device"
+		}`
+
+		args := &skel.CmdArgs{
+			ContainerID: "dummy",
+			Netns:       originalNS.Path(),
+			IfName:      ifname,
+			StdinData:   []byte(conf),
+		}
+		_, _, err := testutils.CmdAddWithResult(originalNS.Path(), ifname, []byte(conf), func() error { return cmdAdd(args) })
+		Expect(err).To(MatchError(`specify either "device", "hwaddr" or "kernelpath"`))
+
+	})
+
+})