forked from containernetworking/plugins
/
host-device.go
411 lines (355 loc) · 11.1 KB
/
host-device.go
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// 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"
"errors"
"fmt"
"io/ioutil"
"net"
"os"
"path/filepath"
"runtime"
"strings"
"github.com/vishvananda/netlink"
"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/ip"
"github.com/containernetworking/plugins/pkg/ipam"
"github.com/containernetworking/plugins/pkg/ns"
bv "github.com/containernetworking/plugins/pkg/utils/buildversion"
)
const (
sysBusPCI = "/sys/bus/pci/devices"
)
//NetConf for host-device config, look the README to learn how to use those parameters
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
PCIAddr string `json:"pciBusID"` // PCI Address of target network 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 == "" && n.PCIAddr == "" {
return nil, fmt.Errorf(`specify either "device", "hwaddr", "kernelpath" or "pciBusID"`)
}
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()
hostDev, err := getLink(cfg.Device, cfg.HWAddr, cfg.KernelPath, cfg.PCIAddr)
if err != nil {
return fmt.Errorf("failed to find host device: %v", err)
}
contDev, err := moveLinkIn(hostDev, containerNs, args.IfName)
if err != nil {
return fmt.Errorf("failed to move link %v", err)
}
var result *current.Result
// run the IPAM plugin and get back the config to apply
if cfg.IPAM.Type != "" {
r, err := ipam.ExecAdd(cfg.IPAM.Type, args.StdinData)
if err != nil {
return err
}
// Invoke ipam del if err to avoid ip leak
defer func() {
if err != nil {
ipam.ExecDel(cfg.IPAM.Type, args.StdinData)
}
}()
// Convert whatever the IPAM result was into the current Result type
result, err = current.NewResultFromResult(r)
if err != nil {
return err
}
if len(result.IPs) == 0 {
return errors.New("IPAM plugin returned missing IP config")
}
result.Interfaces = []*current.Interface{{
Name: contDev.Attrs().Name,
Mac: contDev.Attrs().HardwareAddr.String(),
Sandbox: containerNs.Path(),
}}
for _, ipc := range result.IPs {
// All addresses apply to the container interface (move from host)
ipc.Interface = current.Int(0)
}
err = containerNs.Do(func(_ ns.NetNS) error {
if err := ipam.ConfigureIface(args.IfName, result); err != nil {
return err
}
return nil
})
if err != nil {
return err
}
result.DNS = cfg.DNS
return types.PrintResult(result, cfg.CNIVersion)
}
return printLink(contDev, cfg.CNIVersion, containerNs)
}
func cmdDel(args *skel.CmdArgs) error {
cfg, err := loadConf(args.StdinData)
if err != nil {
return err
}
if args.Netns == "" {
return nil
}
containerNs, err := ns.GetNS(args.Netns)
if err != nil {
return fmt.Errorf("failed to open netns %q: %v", args.Netns, err)
}
defer containerNs.Close()
if err := moveLinkOut(containerNs, args.IfName); err != nil {
return err
}
if cfg.IPAM.Type != "" {
if err := ipam.ExecDel(cfg.IPAM.Type, args.StdinData); err != nil {
return err
}
}
return nil
}
func moveLinkIn(hostDev netlink.Link, containerNs ns.NetNS, ifName string) (netlink.Link, error) {
if err := netlink.LinkSetNsFd(hostDev, int(containerNs.Fd())); err != nil {
return nil, err
}
var contDev netlink.Link
if err := containerNs.Do(func(_ ns.NetNS) error {
var err error
contDev, err = netlink.LinkByName(hostDev.Attrs().Name)
if err != nil {
return fmt.Errorf("failed to find %q: %v", hostDev.Attrs().Name, err)
}
// Save host device name into the container device's alias property
if err := netlink.LinkSetAlias(contDev, hostDev.Attrs().Name); err != nil {
return fmt.Errorf("failed to set alias to %q: %v", hostDev.Attrs().Name, err)
}
// Rename container device to respect args.IfName
if err := netlink.LinkSetName(contDev, ifName); err != nil {
return fmt.Errorf("failed to rename device %q to %q: %v", hostDev.Attrs().Name, ifName, err)
}
// Retrieve link again to get up-to-date name and attributes
contDev, err = netlink.LinkByName(ifName)
if err != nil {
return fmt.Errorf("failed to find %q: %v", ifName, err)
}
return nil
}); err != nil {
return nil, err
}
return contDev, nil
}
func moveLinkOut(containerNs ns.NetNS, ifName string) error {
defaultNs, err := ns.GetCurrentNS()
if err != nil {
return err
}
defer defaultNs.Close()
return containerNs.Do(func(_ ns.NetNS) error {
dev, err := netlink.LinkByName(ifName)
if err != nil {
return fmt.Errorf("failed to find %q: %v", ifName, err)
}
// Devices can be renamed only when down
if err := netlink.LinkSetDown(dev); err != nil {
return fmt.Errorf("failed to set %q down: %v", ifName, err)
}
// Rename device to it's original name
if err := netlink.LinkSetName(dev, dev.Attrs().Alias); err != nil {
return fmt.Errorf("failed to restore %q to original name %q: %v", ifName, dev.Attrs().Alias, err)
}
if err := netlink.LinkSetNsFd(dev, int(defaultNs.Fd())); err != nil {
return fmt.Errorf("failed to move %q to host netns: %v", dev.Attrs().Alias, err)
}
return nil
})
}
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, pciaddr 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 {
return netlink.LinkByName(devname)
} 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
}
}
}
} else if len(pciaddr) > 0 {
netDir := filepath.Join(sysBusPCI, pciaddr, "net")
if _, err := os.Lstat(netDir); err != nil {
return nil, fmt.Errorf("no net directory under pci device %s: %q", pciaddr, err)
}
fInfo, err := ioutil.ReadDir(netDir)
if err != nil {
return nil, fmt.Errorf("failed to read net directory %s: %q", netDir, err)
}
if len(fInfo) > 0 {
return netlink.LinkByName(fInfo[0].Name())
}
return nil, fmt.Errorf("failed to find device name for pci address %s", pciaddr)
}
return nil, fmt.Errorf("failed to find physical interface")
}
func main() {
skel.PluginMain(cmdAdd, cmdCheck, cmdDel, version.All, bv.BuildString("host-device"))
}
func cmdCheck(args *skel.CmdArgs) error {
cfg, err := loadConf(args.StdinData)
if err != nil {
return err
}
netns, err := ns.GetNS(args.Netns)
if err != nil {
return fmt.Errorf("failed to open netns %q: %v", args.Netns, err)
}
defer netns.Close()
// run the IPAM plugin and get back the config to apply
if cfg.IPAM.Type != "" {
err = ipam.ExecCheck(cfg.IPAM.Type, args.StdinData)
if err != nil {
return err
}
}
// Parse previous result.
if cfg.NetConf.RawPrevResult == nil {
return fmt.Errorf("Required prevResult missing")
}
if err := version.ParsePrevResult(&cfg.NetConf); err != nil {
return err
}
result, err := current.NewResultFromResult(cfg.PrevResult)
if err != nil {
return err
}
var contMap current.Interface
// Find interfaces for name we know, that of host-device inside container
for _, intf := range result.Interfaces {
if args.IfName == intf.Name {
if args.Netns == intf.Sandbox {
contMap = *intf
continue
}
}
}
// The namespace must be the same as what was configured
if args.Netns != contMap.Sandbox {
return fmt.Errorf("Sandbox in prevResult %s doesn't match configured netns: %s",
contMap.Sandbox, args.Netns)
}
//
// Check prevResults for ips, routes and dns against values found in the container
if err := netns.Do(func(_ ns.NetNS) error {
// Check interface against values found in the container
err := validateCniContainerInterface(contMap)
if err != nil {
return err
}
err = ip.ValidateExpectedInterfaceIPs(args.IfName, result.IPs)
if err != nil {
return err
}
err = ip.ValidateExpectedRoute(result.Routes)
if err != nil {
return err
}
return nil
}); err != nil {
return err
}
//
return nil
}
func validateCniContainerInterface(intf current.Interface) error {
var link netlink.Link
var err error
if intf.Name == "" {
return fmt.Errorf("Container interface name missing in prevResult: %v", intf.Name)
}
link, err = netlink.LinkByName(intf.Name)
if err != nil {
return fmt.Errorf("Container Interface name in prevResult: %s not found", intf.Name)
}
if intf.Sandbox == "" {
return fmt.Errorf("Error: Container interface %s should not be in host namespace", link.Attrs().Name)
}
if intf.Mac != "" {
if intf.Mac != link.Attrs().HardwareAddr.String() {
return fmt.Errorf("Interface %s Mac %s doesn't match container Mac: %s", intf.Name, intf.Mac, link.Attrs().HardwareAddr)
}
}
return nil
}