// setLinkOptions validates and sets link's various options passed in as LinkOptions.
func setLinkOptions(ifc *net.Interface, opts LinkOptions) error {
macaddr, mtu, flags, ns := opts.MacAddr, opts.MTU, opts.Flags, opts.Ns
// if MTU is passed in LinkOptions
if mtu != 0 {
if err := validMtu(mtu); err != nil {
return err
}
if err := netlink.NetworkSetMTU(ifc, mtu); err != nil {
return fmt.Errorf("Unable to set MTU: %s", err)
}
}
// if MacAddress is passed in LinkOptions
if macaddr != "" {
if err := validMacAddress(macaddr); err != nil {
return err
}
if err := netlink.NetworkSetMacAddress(ifc, macaddr); err != nil {
return fmt.Errorf("Unable to set MAC Address: %s", err)
}
}
// if ns is passed in LinkOptions
if ns != 0 {
if err := validNs(ns); err != nil {
return err
}
if err := netlink.NetworkSetNsPid(ifc, ns); err != nil {
return fmt.Errorf("Unable to set Network namespace: %s", err)
}
}
// if flags is passed in LinkOptions
if flags != 0 {
if err := validFlags(flags); err != nil {
return err
}
if ns != 0 && (ns != 1 || ns != os.Getpid()) {
if (flags & syscall.IFF_UP) == syscall.IFF_UP {
origNs, _ := NetNsHandle(os.Getpid())
defer syscall.Close(int(origNs))
defer system.Setns(origNs, syscall.CLONE_NEWNET)
if err := SetNetNsToPid(ns); err != nil {
return fmt.Errorf("Switching to %d network namespace failed: %s", ns, err)
}
if err := netlink.NetworkLinkUp(ifc); err != nil {
return fmt.Errorf("Unable to bring %s interface UP: %s", ifc.Name, ns)
}
}
} else {
if err := netlink.NetworkLinkUp(ifc); err != nil {
return fmt.Errorf("Could not bring up network link %s: %s", ifc.Name, err)
}
}
}
return nil
}
// SetLinkMTU sets link's MTU.
// It is equivalent of running: ip link set dev ${interface name} mtu ${MTU value}
func (l *Link) SetLinkMTU(mtu int) error {
return netlink.NetworkSetMTU(l.NetInterface(), mtu)
}