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|
package main
import (
"errors"
"fmt"
"os/exec"
)
type NetType string
const (
NetNs NetType = "netns"
Veth string = "veth"
Tap string = "tap"
)
type NetConfig struct {
Configure func() error
Unconfigure func()
}
type NetTopology []NetConfig
func (t *NetTopology) Configure() error {
for _, c := range *t {
err := c.Configure()
if err != nil {
return err
}
}
return nil
}
func (t *NetTopology) Unconfigure() {
for _, c := range *t {
c.Unconfigure()
}
}
func newConfigFn(cfg NetDevConfig) func() error {
t := cfg["type"]
if t == "netns" {
return func() error { return AddNetns(cfg["name"].(string)) }
} else if t == "veth" {
return func() error {
var peerNs string
peer := cfg["peer"].(NetDevConfig)
peerName := peer["name"].(string)
err := AddVethPair(cfg["name"].(string), peerName)
if err != nil {
return err
}
if peer["netns"] != nil {
peerNs = peer["netns"].(string)
if peerNs != "" {
err := LinkSetNetns(peerName, peerNs)
if err != nil {
return err
}
}
}
if peer["ip4"] != nil {
err = AddAddress(peerName, peer["ip4"].(string), peerNs)
if err != nil {
return fmt.Errorf("failed to add configure address for %s: %v", peerName, err)
}
}
return nil
}
} else if t == "bridge" {
return func() error { return configureBridge(cfg) }
} else if t == "tap" {
return func() error { return configureTap(cfg) }
}
return nil
}
func newUnconfigFn(cfg NetDevConfig) func() {
t := cfg["type"]
name := cfg["name"].(string)
if t == "tap" {
return func() { DelLink(name) }
} else if t == "netns" {
return func() { DelNetns(name) }
} else if t == "veth" {
return func() { DelLink(name) }
} else if t == "bridge" {
return func() { DelBridge(name, cfg["netns"].(string)) }
}
return nil
}
func NewNetConfig(cfg NetDevConfig) NetConfig {
var nc NetConfig
nc.Configure = newConfigFn(cfg)
nc.Unconfigure = newUnconfigFn(cfg)
return nc
}
func DelBridge(brName, ns string) error {
err := SetDevDown(brName, ns)
if err != err {
return err
}
err = addDelBridge(brName, ns, false)
if err != nil {
return err
}
return nil
}
func configureBridge(dev NetDevConfig) error {
var ifs []string
for _, v := range dev["interfaces"].([]interface{}) {
ifs = append(ifs, v.(string))
}
return AddBridge(dev["name"].(string), ifs, dev["netns"].(string))
}
func configureTap(dev NetDevConfig) error {
return AddTap(dev["name"].(string), dev["ip4"].(string))
}
func SetDevUp(dev, ns string) error {
return setDevUpDown(dev, ns, true)
}
func SetDevDown(dev, ns string) error {
return setDevUpDown(dev, ns, false)
}
func AddTap(ifName, ifAddress string) error {
cmd := exec.Command("ip", "tuntap", "add", ifName, "mode", "tap")
o, err := cmd.CombinedOutput()
if err != nil {
s := fmt.Sprintf("error creating tap %s: %v: %s", ifName, err, string(o))
return errors.New(s)
}
cmd = exec.Command("ip", "addr", "add", ifAddress, "dev", ifName)
err = cmd.Run()
if err != nil {
DelLink(ifName)
s := fmt.Sprintf("error setting addr for tap %s: %v", ifName, err)
return errors.New(s)
}
err = SetDevUp(ifName, "")
if err != nil {
DelLink(ifName)
return err
}
return nil
}
func DelLink(ifName string) {
cmd := exec.Command("ip", "link", "del", ifName)
cmd.Run()
}
func setDevUpDown(dev, ns string, isUp bool) error {
var op string
if isUp {
op = "up"
} else {
op = "down"
}
c := []string{"ip", "link", "set", "dev", dev, op}
cmd := appendNetns(c, ns)
err := cmd.Run()
if err != nil {
s := fmt.Sprintf("error bringing %s device %s!", dev, op)
return errors.New(s)
}
return nil
}
func AddVethPair(ifName, peerName string) error {
cmd := exec.Command("ip", "link", "add", ifName, "type", "veth", "peer", "name", peerName)
err := cmd.Run()
if err != nil {
return fmt.Errorf("creating veth pair failed: %v", err)
}
err = SetDevUp(ifName, "")
if err != nil {
return fmt.Errorf("set link up failed: %v", err)
}
return nil
}
func addDelNetns(name string, isAdd bool) error {
var op string
if isAdd {
op = "add"
} else {
op = "del"
}
cmd := exec.Command("ip", "netns", op, name)
_, err := cmd.CombinedOutput()
if err != nil {
return errors.New("add/del netns failed")
}
return nil
}
func AddNetns(nsName string) error {
return addDelNetns(nsName, true)
}
func DelNetns(nsName string) error {
return addDelNetns(nsName, false)
}
func LinkSetNetns(ifName, ns string) error {
cmd := exec.Command("ip", "link", "set", "dev", ifName, "up", "netns", ns)
err := cmd.Run()
if err != nil {
return fmt.Errorf("error setting device '%s' to netns '%s: %v", ifName, ns, err)
}
return nil
}
func NewCommand(s []string, ns string) *exec.Cmd {
return appendNetns(s, ns)
}
func appendNetns(s []string, ns string) *exec.Cmd {
var cmd *exec.Cmd
if ns == "" {
// use default namespace
cmd = exec.Command(s[0], s[1:]...)
} else {
var args = []string{"netns", "exec", ns}
args = append(args, s[:]...)
cmd = exec.Command("ip", args...)
}
return cmd
}
func addDelBridge(brName, ns string, isAdd bool) error {
var op string
if isAdd {
op = "addbr"
} else {
op = "delbr"
}
var c = []string{"brctl", op, brName}
cmd := appendNetns(c, ns)
err := cmd.Run()
if err != nil {
s := fmt.Sprintf("%s %s failed!", op, brName)
return errors.New(s)
}
return nil
}
func AddBridge(brName string, ifs []string, ns string) error {
err := addDelBridge(brName, ns, true)
if err != nil {
return err
}
for _, v := range ifs {
c := []string{"brctl", "addif", brName, v}
cmd := appendNetns(c, ns)
err = cmd.Run()
if err != nil {
s := fmt.Sprintf("error adding %s to bridge %s: %v", v, brName, err)
return errors.New(s)
}
}
err = SetDevUp(brName, ns)
if err != nil {
return err
}
return nil
}
|
