[host-device] integrated `getLink()` function which maps either devicename, hw-addr...

diff --git a/plugins/host-device/host-device.go b/plugins/host-device/host-device.go
index a487085..853cab9 100644 (file)
--- a/plugins/host-device/host-device.go
+++ b/plugins/host-device/host-device.go
@@ -15,9 +15,14 @@
 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"
@@ -26,7 +31,9 @@ import (
 )
 
 type NetConf struct {
-       Device string `json:"device"`
+       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() {
@@ -41,8 +48,8 @@ func loadConf(bytes []byte) (*NetConf, error) {
        if err := json.Unmarshal(bytes, n); err != nil {
                return nil, fmt.Errorf("failed to load netconf: %v", err)
        }
-       if n.Device == "" {
-               return nil, fmt.Errorf(`"device" field is required. It specifies the host device to put into the pod`)
+       if n.Device == "" && n.HWAddr == "" && n.KernelPath == "" {
+               return nil, fmt.Errorf(`specify either "device", "hwaddr" or "kernelpath"`)
        }
        return n, nil
 }
@@ -57,7 +64,7 @@ func cmdAdd(args *skel.CmdArgs) error {
                return fmt.Errorf("failed to open netns %q: %v", args.Netns, err)
        }
        defer containerNs.Close()
-       return addLink(cfg.Device, containerNs)
+       return addLink(cfg.Device, cfg.HWAddr, cfg.KernelPath, containerNs)
 }
 
 func cmdDel(args *skel.CmdArgs) error {
@@ -70,21 +77,21 @@ func cmdDel(args *skel.CmdArgs) error {
                return fmt.Errorf("failed to open netns %q: %v", args.Netns, err)
        }
        defer containerNs.Close()
-       return removeLink(cfg.Device, containerNs)
+       return removeLink(cfg.Device, cfg.HWAddr, cfg.KernelPath, containerNs)
 }
 
-func addLink(name string, containerNs ns.NetNS) error {
-       dev, err := netlink.LinkByName(name)
+func addLink(device, hwAddr, kernelPath string, containerNs ns.NetNS) error {
+       dev, err := getLink(device, hwAddr, kernelPath)
        if err != nil {
-               return fmt.Errorf("failed to lookup %v: %v", name, err)
+               return err
        }
        return netlink.LinkSetNsFd(dev, int(containerNs.Fd()))
 }
 
-func removeLink(name string, containerNs ns.NetNS) error {
+func removeLink(device, hwAddr, kernelPath string, containerNs ns.NetNS) error {
        var dev netlink.Link
        err := containerNs.Do(func(_ ns.NetNS) error {
-               d, err := netlink.LinkByName(name)
+               d, err := getLink(device, hwAddr, kernelPath)
                if err != nil {
                        return err
                }
@@ -101,6 +108,51 @@ func removeLink(name string, containerNs ns.NetNS) error {
        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)
 }