Dan Williams faf6d2629d
Merge pull request #626 from Luap99/tuning-mac
tuning: always update MAC in CNI result
2021-05-05 10:24:13 -05:00

489 lines
13 KiB
Go

// 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.
// This is a "meta-plugin". It reads in its own netconf, it does not create
// any network interface but just changes the network sysctl.
package main
import (
"encoding/json"
"fmt"
"io/ioutil"
"net"
"os"
"path"
"path/filepath"
"strings"
"github.com/j-keck/arping"
"github.com/vishvananda/netlink"
"golang.org/x/sys/unix"
"github.com/containernetworking/cni/pkg/skel"
"github.com/containernetworking/cni/pkg/types"
current "github.com/containernetworking/cni/pkg/types/100"
"github.com/containernetworking/cni/pkg/version"
"github.com/containernetworking/plugins/pkg/ns"
bv "github.com/containernetworking/plugins/pkg/utils/buildversion"
)
const defaultDataDir = "/run/cni/tuning"
// TuningConf represents the network tuning configuration.
type TuningConf struct {
types.NetConf
DataDir string `json:"dataDir,omitempty"`
SysCtl map[string]string `json:"sysctl"`
Mac string `json:"mac,omitempty"`
Promisc bool `json:"promisc,omitempty"`
Mtu int `json:"mtu,omitempty"`
Allmulti *bool `json:"allmulti,omitempty"`
RuntimeConfig struct {
Mac string `json:"mac,omitempty"`
} `json:"runtimeConfig,omitempty"`
Args *struct {
A *IPAMArgs `json:"cni"`
} `json:"args"`
}
type IPAMArgs struct {
SysCtl *map[string]string `json:"sysctl"`
Mac *string `json:"mac,omitempty"`
Promisc *bool `json:"promisc,omitempty"`
Mtu *int `json:"mtu,omitempty"`
Allmulti *bool `json:"allmulti,omitempty"`
}
// configToRestore will contain interface attributes that should be restored on cmdDel
type configToRestore struct {
Mac string `json:"mac,omitempty"`
Promisc *bool `json:"promisc,omitempty"`
Mtu int `json:"mtu,omitempty"`
Allmulti *bool `json:"allmulti,omitempty"`
}
// MacEnvArgs represents CNI_ARG
type MacEnvArgs struct {
types.CommonArgs
MAC types.UnmarshallableString `json:"mac,omitempty"`
}
func parseConf(data []byte, envArgs string) (*TuningConf, error) {
conf := TuningConf{Promisc: false}
if err := json.Unmarshal(data, &conf); err != nil {
return nil, fmt.Errorf("failed to load netconf: %v", err)
}
if conf.DataDir == "" {
conf.DataDir = defaultDataDir
}
// Parse custom Mac from both env args
if envArgs != "" {
e := MacEnvArgs{}
err := types.LoadArgs(envArgs, &e)
if err != nil {
return nil, err
}
if e.MAC != "" {
conf.Mac = string(e.MAC)
}
}
// Parse custom Mac from RuntimeConfig
if conf.RuntimeConfig.Mac != "" {
conf.Mac = conf.RuntimeConfig.Mac
}
// Get args
if conf.Args != nil && conf.Args.A != nil {
if conf.Args.A.SysCtl != nil {
for k, v := range *conf.Args.A.SysCtl {
conf.SysCtl[k] = v
}
}
if conf.Args.A.Mac != nil {
conf.Mac = *conf.Args.A.Mac
}
if conf.Args.A.Promisc != nil {
conf.Promisc = *conf.Args.A.Promisc
}
if conf.Args.A.Mtu != nil {
conf.Mtu = *conf.Args.A.Mtu
}
if conf.Args.A.Allmulti != nil {
conf.Allmulti = conf.Args.A.Allmulti
}
}
return &conf, nil
}
func changeMacAddr(ifName string, newMacAddr string) error {
addr, err := net.ParseMAC(newMacAddr)
if err != nil {
return fmt.Errorf("invalid args %v for MAC addr: %v", newMacAddr, err)
}
link, err := netlink.LinkByName(ifName)
if err != nil {
return fmt.Errorf("failed to get %q: %v", ifName, err)
}
return netlink.LinkSetHardwareAddr(link, addr)
}
func updateResultsMacAddr(config *TuningConf, ifName string, newMacAddr string) {
// Parse previous result.
if config.PrevResult == nil {
return
}
version.ParsePrevResult(&config.NetConf)
result, _ := current.NewResultFromResult(config.PrevResult)
for _, i := range result.Interfaces {
if i.Name == ifName {
i.Mac = newMacAddr
}
}
config.PrevResult = result
}
func changePromisc(ifName string, val bool) error {
link, err := netlink.LinkByName(ifName)
if err != nil {
return fmt.Errorf("failed to get %q: %v", ifName, err)
}
if val {
return netlink.SetPromiscOn(link)
}
return netlink.SetPromiscOff(link)
}
func changeMtu(ifName string, mtu int) error {
link, err := netlink.LinkByName(ifName)
if err != nil {
return fmt.Errorf("failed to get %q: %v", ifName, err)
}
return netlink.LinkSetMTU(link, mtu)
}
func changeAllmulti(ifName string, val bool) error {
link, err := netlink.LinkByName(ifName)
if err != nil {
return fmt.Errorf("failed to get %q: %v", ifName, err)
}
if val {
return netlink.LinkSetAllmulticastOn(link)
}
return netlink.LinkSetAllmulticastOff(link)
}
func createBackup(ifName, containerID, backupPath string, tuningConf *TuningConf) error {
config := configToRestore{}
link, err := netlink.LinkByName(ifName)
if err != nil {
return fmt.Errorf("failed to get %q: %v", ifName, err)
}
if tuningConf.Mac != "" {
config.Mac = link.Attrs().HardwareAddr.String()
}
if tuningConf.Promisc {
config.Promisc = new(bool)
*config.Promisc = (link.Attrs().Promisc != 0)
}
if tuningConf.Mtu != 0 {
config.Mtu = link.Attrs().MTU
}
if tuningConf.Allmulti != nil {
config.Allmulti = new(bool)
*config.Allmulti = (link.Attrs().RawFlags&unix.IFF_ALLMULTI != 0)
}
if _, err := os.Stat(backupPath); os.IsNotExist(err) {
if err = os.MkdirAll(backupPath, 0600); err != nil {
return fmt.Errorf("failed to create backup directory: %v", err)
}
}
data, err := json.MarshalIndent(config, "", " ")
if err != nil {
return fmt.Errorf("failed to marshall data for %q: %v", ifName, err)
}
if err = ioutil.WriteFile(path.Join(backupPath, containerID+"_"+ifName+".json"), data, 0600); err != nil {
return fmt.Errorf("failed to save file %s.json: %v", ifName, err)
}
return nil
}
func restoreBackup(ifName, containerID, backupPath string) error {
filePath := path.Join(backupPath, containerID+"_"+ifName+".json")
if _, err := os.Stat(filePath); os.IsNotExist(err) {
// No backup file - nothing to revert
return nil
}
file, err := ioutil.ReadFile(filePath)
if err != nil {
return fmt.Errorf("failed to open file %q: %v", filePath, err)
}
config := configToRestore{}
if err = json.Unmarshal([]byte(file), &config); err != nil {
return nil
}
var errStr []string
_, err = netlink.LinkByName(ifName)
if err != nil {
return nil
}
if config.Mtu != 0 {
if err = changeMtu(ifName, config.Mtu); err != nil {
err = fmt.Errorf("failed to restore MTU: %v", err)
errStr = append(errStr, err.Error())
}
}
if config.Mac != "" {
if err = changeMacAddr(ifName, config.Mac); err != nil {
err = fmt.Errorf("failed to restore MAC address: %v", err)
errStr = append(errStr, err.Error())
}
}
if config.Promisc != nil {
if err = changePromisc(ifName, *config.Promisc); err != nil {
err = fmt.Errorf("failed to restore promiscuous mode: %v", err)
errStr = append(errStr, err.Error())
}
}
if config.Allmulti != nil {
if err = changeAllmulti(ifName, *config.Allmulti); err != nil {
err = fmt.Errorf("failed to restore all-multicast mode: %v", err)
errStr = append(errStr, err.Error())
}
}
if len(errStr) > 0 {
return fmt.Errorf(strings.Join(errStr, "; "))
}
if err = os.Remove(filePath); err != nil {
return fmt.Errorf("failed to remove file %v: %v", filePath, err)
}
return nil
}
func cmdAdd(args *skel.CmdArgs) error {
tuningConf, err := parseConf(args.StdinData, args.Args)
if err != nil {
return err
}
// Parse previous result.
if tuningConf.RawPrevResult == nil {
return fmt.Errorf("Required prevResult missing")
}
if err := version.ParsePrevResult(&tuningConf.NetConf); err != nil {
return err
}
result, err := current.NewResultFromResult(tuningConf.PrevResult)
if err != nil {
return err
}
// The directory /proc/sys/net is per network namespace. Enter in the
// network namespace before writing on it.
err = ns.WithNetNSPath(args.Netns, func(_ ns.NetNS) error {
for key, value := range tuningConf.SysCtl {
fileName := filepath.Join("/proc/sys", strings.Replace(key, ".", "/", -1))
fileName = filepath.Clean(fileName)
// Refuse to modify sysctl parameters that don't belong
// to the network subsystem.
if !strings.HasPrefix(fileName, "/proc/sys/net/") {
return fmt.Errorf("invalid net sysctl key: %q", key)
}
content := []byte(value)
err := ioutil.WriteFile(fileName, content, 0644)
if err != nil {
return err
}
}
if tuningConf.Mac != "" || tuningConf.Mtu != 0 || tuningConf.Promisc || tuningConf.Allmulti != nil {
if err = createBackup(args.IfName, args.ContainerID, tuningConf.DataDir, tuningConf); err != nil {
return err
}
}
if tuningConf.Mac != "" {
if err = changeMacAddr(args.IfName, tuningConf.Mac); err != nil {
return err
}
for _, ipc := range result.IPs {
if ipc.Address.IP.To4() != nil {
_ = arping.GratuitousArpOverIfaceByName(ipc.Address.IP, args.IfName)
}
}
updateResultsMacAddr(tuningConf, args.IfName, tuningConf.Mac)
}
if tuningConf.Promisc != false {
if err = changePromisc(args.IfName, true); err != nil {
return err
}
}
if tuningConf.Mtu != 0 {
if err = changeMtu(args.IfName, tuningConf.Mtu); err != nil {
return err
}
}
if tuningConf.Allmulti != nil {
if err = changeAllmulti(args.IfName, *tuningConf.Allmulti); err != nil {
return err
}
}
return nil
})
if err != nil {
return err
}
return types.PrintResult(tuningConf.PrevResult, tuningConf.CNIVersion)
}
// cmdDel will restore NIC attributes to the original ones when called
func cmdDel(args *skel.CmdArgs) error {
tuningConf, err := parseConf(args.StdinData, args.Args)
if err != nil {
return err
}
ns.WithNetNSPath(args.Netns, func(_ ns.NetNS) error {
// MAC address, MTU, promiscuous and all-multicast mode settings will be restored
return restoreBackup(args.IfName, args.ContainerID, tuningConf.DataDir)
})
return nil
}
func main() {
skel.PluginMain(cmdAdd, cmdCheck, cmdDel, version.All, bv.BuildString("tuning"))
}
func cmdCheck(args *skel.CmdArgs) error {
tuningConf, err := parseConf(args.StdinData, args.Args)
if err != nil {
return err
}
// Parse previous result.
if tuningConf.RawPrevResult == nil {
return fmt.Errorf("Required prevResult missing")
}
if err := version.ParsePrevResult(&tuningConf.NetConf); err != nil {
return err
}
_, err = current.NewResultFromResult(tuningConf.PrevResult)
if err != nil {
return err
}
err = ns.WithNetNSPath(args.Netns, func(_ ns.NetNS) error {
// Check each configured value vs what's currently in the container
for key, confValue := range tuningConf.SysCtl {
fileName := filepath.Join("/proc/sys", strings.Replace(key, ".", "/", -1))
fileName = filepath.Clean(fileName)
contents, err := ioutil.ReadFile(fileName)
if err != nil {
return err
}
curValue := strings.TrimSuffix(string(contents), "\n")
if confValue != curValue {
return fmt.Errorf("Error: Tuning configured value of %s is %s, current value is %s", fileName, confValue, curValue)
}
}
link, err := netlink.LinkByName(args.IfName)
if err != nil {
return fmt.Errorf("Cannot find container link %v", args.IfName)
}
if tuningConf.Mac != "" {
if tuningConf.Mac != link.Attrs().HardwareAddr.String() {
return fmt.Errorf("Error: Tuning configured Ethernet of %s is %s, current value is %s",
args.IfName, tuningConf.Mac, link.Attrs().HardwareAddr)
}
}
if tuningConf.Promisc {
if link.Attrs().Promisc == 0 {
return fmt.Errorf("Error: Tuning link %s configured promisc is %v, current value is %d",
args.IfName, tuningConf.Promisc, link.Attrs().Promisc)
}
} else {
if link.Attrs().Promisc != 0 {
return fmt.Errorf("Error: Tuning link %s configured promisc is %v, current value is %d",
args.IfName, tuningConf.Promisc, link.Attrs().Promisc)
}
}
if tuningConf.Mtu != 0 {
if tuningConf.Mtu != link.Attrs().MTU {
return fmt.Errorf("Error: Tuning configured MTU of %s is %d, current value is %d",
args.IfName, tuningConf.Mtu, link.Attrs().MTU)
}
}
if tuningConf.Allmulti != nil {
allmulti := (link.Attrs().RawFlags&unix.IFF_ALLMULTI != 0)
if allmulti != *tuningConf.Allmulti {
return fmt.Errorf("Error: Tuning configured all-multicast mode of %s is %v, current value is %v",
args.IfName, tuningConf.Allmulti, allmulti)
}
}
return nil
})
if err != nil {
return err
}
return nil
}