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- package portmapper
- import (
- "fmt"
- "io"
- "io/ioutil"
- "net"
- "os"
- "os/exec"
- "time"
- )
- const userlandProxyCommandName = "docker-proxy"
- type userlandProxy interface {
- Start() error
- Stop() error
- }
- // proxyCommand wraps an exec.Cmd to run the userland TCP and UDP
- // proxies as separate processes.
- type proxyCommand struct {
- cmd *exec.Cmd
- }
- func (p *proxyCommand) Start() error {
- r, w, err := os.Pipe()
- if err != nil {
- return fmt.Errorf("proxy unable to open os.Pipe %s", err)
- }
- defer r.Close()
- p.cmd.ExtraFiles = []*os.File{w}
- if err := p.cmd.Start(); err != nil {
- return err
- }
- w.Close()
- errchan := make(chan error, 1)
- go func() {
- buf := make([]byte, 2)
- r.Read(buf)
- if string(buf) != "0\n" {
- errStr, err := ioutil.ReadAll(r)
- if err != nil {
- errchan <- fmt.Errorf("Error reading exit status from userland proxy: %v", err)
- return
- }
- errchan <- fmt.Errorf("Error starting userland proxy: %s", errStr)
- return
- }
- errchan <- nil
- }()
- select {
- case err := <-errchan:
- return err
- case <-time.After(16 * time.Second):
- return fmt.Errorf("Timed out proxy starting the userland proxy")
- }
- }
- func (p *proxyCommand) Stop() error {
- if p.cmd.Process != nil {
- if err := p.cmd.Process.Signal(os.Interrupt); err != nil {
- return err
- }
- return p.cmd.Wait()
- }
- return nil
- }
- // dummyProxy just listen on some port, it is needed to prevent accidental
- // port allocations on bound port, because without userland proxy we using
- // iptables rules and not net.Listen
- type dummyProxy struct {
- listener io.Closer
- addr net.Addr
- }
- func newDummyProxy(proto string, hostIP net.IP, hostPort int) userlandProxy {
- switch proto {
- case "tcp":
- addr := &net.TCPAddr{IP: hostIP, Port: hostPort}
- return &dummyProxy{addr: addr}
- case "udp":
- addr := &net.UDPAddr{IP: hostIP, Port: hostPort}
- return &dummyProxy{addr: addr}
- }
- return nil
- }
- func (p *dummyProxy) Start() error {
- switch addr := p.addr.(type) {
- case *net.TCPAddr:
- l, err := net.ListenTCP("tcp", addr)
- if err != nil {
- return err
- }
- p.listener = l
- case *net.UDPAddr:
- l, err := net.ListenUDP("udp", addr)
- if err != nil {
- return err
- }
- p.listener = l
- default:
- return fmt.Errorf("Unknown addr type: %T", p.addr)
- }
- return nil
- }
- func (p *dummyProxy) Stop() error {
- if p.listener != nil {
- return p.listener.Close()
- }
- return nil
- }
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