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/
container.go
151 lines (122 loc) · 3.27 KB
/
container.go
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// +build linux
package configure
import (
"bytes"
"errors"
"flag"
"fmt"
"net"
"os"
"os/exec"
"strconv"
"syscall"
"github.com/docker/docker/pkg/reexec"
"code.cloudfoundry.org/guardian/kawasaki"
"code.cloudfoundry.org/guardian/kawasaki/devices"
"code.cloudfoundry.org/guardian/kawasaki/netns"
"code.cloudfoundry.org/lager"
)
func init() {
reexec.Register("configure-container-netns", func() {
var netNsPath, containerIntf, containerIPStr, bridgeIPStr, subnetStr string
var mtu int
flag.StringVar(&netNsPath, "netNsPath", "", "netNsPath")
flag.StringVar(&containerIntf, "containerIntf", "", "containerIntf")
flag.StringVar(&containerIPStr, "containerIP", "", "containerIP")
flag.StringVar(&bridgeIPStr, "bridgeIP", "", "bridgeIP")
flag.StringVar(&subnetStr, "subnet", "", "subnet")
flag.IntVar(&mtu, "mtu", 0, "mtu")
flag.Parse()
fd, err := os.Open(netNsPath)
if err != nil {
fmt.Fprintf(os.Stderr, "opening netns `%s`: %s", netNsPath, err)
os.Exit(1)
}
defer fd.Close()
netNsExecer := &netns.Execer{}
if err = netNsExecer.Exec(fd, func() error {
containerIP := net.ParseIP(containerIPStr)
bridgeIP := net.ParseIP(bridgeIPStr)
_, subnetIPNet, err := net.ParseCIDR(subnetStr)
if err != nil {
panic(err)
}
link := devices.Link{}
intf, found, err := link.InterfaceByName(containerIntf)
if err != nil {
panic(err)
}
if !found {
return fmt.Errorf("interface `%s` was not found", containerIntf)
}
if err := link.AddIP(intf, containerIP, subnetIPNet); err != nil {
panic(err)
}
if err := link.SetUp(intf); err != nil {
panic(err)
}
if err := link.AddDefaultGW(intf, bridgeIP); err != nil {
panic(err)
}
if err := link.SetMTU(intf, mtu); err != nil {
panic(err)
}
return nil
}); err != nil {
fmt.Fprintf(os.Stderr, err.Error())
os.Exit(1)
}
})
}
type Container struct {
FileOpener netns.Opener
}
func (c *Container) Apply(log lager.Logger, cfg kawasaki.NetworkConfig, pid int) error {
netns, err := c.FileOpener.Open(fmt.Sprintf("/proc/%d/ns/net", pid))
if err != nil {
return err
}
defer netns.Close()
log = log.Session("configure-container-netns", lager.Data{
"networkConfig": cfg,
"netNsPath": netns.Name(),
})
cmd := reexec.Command("configure-container-netns",
"-netNsPath", netns.Name(),
"-containerIntf", cfg.ContainerIntf,
"-containerIP", cfg.ContainerIP.String(),
"-bridgeIP", cfg.BridgeIP.String(),
"-subnet", cfg.Subnet.String(),
"-mtu", strconv.FormatInt(int64(cfg.Mtu), 10),
)
errBuf := bytes.NewBuffer([]byte{})
cmd.Stderr = errBuf
if err := cmd.Start(); err != nil {
log.Error("starting-command", errors.New(errBuf.String()))
return err
}
if err := cmd.Wait(); err != nil {
status, err := exitStatus(err)
if err != nil {
log.Error("waiting-for-command", errors.New(errBuf.String()))
return err
}
if status == 1 {
return errors.New(errBuf.String())
}
log.Error("unexpected-error", errors.New(errBuf.String()))
return errors.New("unexpected error")
}
return nil
}
func exitStatus(err error) (uint32, error) {
exitErr, ok := err.(*exec.ExitError)
if !ok {
return 2, err
}
status, ok := exitErr.Sys().(syscall.WaitStatus)
if !ok {
return 2, exitErr
}
return uint32(status.ExitStatus()), nil
}