// execute f() in tgtNS
func withNetNS(curNS, tgtNS *os.File, f func() error) error {
if err := ns.SetNS(tgtNS, syscall.CLONE_NEWNET); err != nil {
return err
}
if err := f(); err != nil {
// Attempt to revert the net ns in a known state
if err := ns.SetNS(curNS, syscall.CLONE_NEWNET); err != nil {
log.Printf("Cannot revert the net namespace: %v", err)
}
return err
}
return ns.SetNS(curNS, syscall.CLONE_NEWNET)
}
func newNetNS() (hostNS, childNS *os.File, err error) {
defer func() {
if err != nil {
if hostNS != nil {
hostNS.Close()
}
if childNS != nil {
childNS.Close()
}
}
}()
hostNS, err = os.Open(selfNetNS)
if err != nil {
return
}
if err = syscall.Unshare(syscall.CLONE_NEWNET); err != nil {
return
}
childNS, err = os.Open(selfNetNS)
if err != nil {
ns.SetNS(hostNS, syscall.CLONE_NEWNET)
return
}
return
}
// enterHostNS moves into the host's network namespace.
func (n *Networking) enterHostNS() error {
return ns.SetNS(n.hostNS, syscall.CLONE_NEWNET)
}