func configureIface(ifname string, ipn ip.IP4Net, mtu int) error {
iface, err := netlink.LinkByName(ifname)
if err != nil {
return fmt.Errorf("failed to lookup interface %v", ifname)
}
err = netlink.AddrAdd(iface, &netlink.Addr{ipn.ToIPNet(), ""})
if err != nil {
return fmt.Errorf("failed to add IP address %v to %v: %v", ipn.String(), ifname, err)
}
err = netlink.LinkSetMTU(iface, mtu)
if err != nil {
return fmt.Errorf("failed to set MTU for %v: %v", ifname, err)
}
err = netlink.LinkSetUp(iface)
if err != nil {
return fmt.Errorf("failed to set interface %v to UP state: %v", ifname, err)
}
// explicitly add a route since there might be a route for a subnet already
// installed by Docker and then it won't get auto added
err = netlink.RouteAdd(&netlink.Route{
LinkIndex: iface.Attrs().Index,
Scope: netlink.SCOPE_UNIVERSE,
Dst: ipn.Network().ToIPNet(),
})
if err != nil && err != syscall.EEXIST {
return fmt.Errorf("Failed to add route (%v -> %v): %v", ipn.Network().String(), ifname, err)
}
return nil
}
func ensureLink(vxlan *netlink.Vxlan) (*netlink.Vxlan, error) {
err := netlink.LinkAdd(vxlan)
if err == syscall.EEXIST {
// it's ok if the device already exists as long as config is similar
existing, err := netlink.LinkByName(vxlan.Name)
if err != nil {
return nil, err
}
incompat := vxlanLinksIncompat(vxlan, existing)
if incompat == "" {
return existing.(*netlink.Vxlan), nil
}
// delete existing
log.Warningf("%q already exists with incompatable configuration: %v; recreating device", vxlan.Name, incompat)
if err = netlink.LinkDel(existing); err != nil {
return nil, fmt.Errorf("failed to delete interface: %v", err)
}
// create new
if err = netlink.LinkAdd(vxlan); err != nil {
return nil, fmt.Errorf("failed to create vxlan interface: %v", err)
}
} else if err != nil {
return nil, err
}
ifindex := vxlan.Index
link, err := netlink.LinkByIndex(vxlan.Index)
if err != nil {
return nil, fmt.Errorf("can't locate created vxlan device with index %v", ifindex)
}
var ok bool
if vxlan, ok = link.(*netlink.Vxlan); !ok {
return nil, fmt.Errorf("created vxlan device with index %v is not vxlan", ifindex)
}
return vxlan, nil
}