func Run(sm *subnet.SubnetManager, tepIface *net.Interface, tepIP net.IP, port int, ipMasq bool, ready backend.ReadyFunc) {
sn, err := acquireLease(sm, tepIP)
if err != nil {
log.Error("Failed to acquire lease: ", err)
return
}
tun, tunName, err := ip.OpenTun("rudder%d")
if err != nil {
log.Error("Failed to open TUN device: ", err)
return
}
localAddr := net.UDPAddr{
Port: port,
}
conn, err := net.ListenUDP("udp4", &localAddr)
if err != nil {
log.Error("Failed to start listening on UDP socket: ", err)
return
}
// Interface's subnet is that of the whole overlay network (e.g. /16)
// and not that of the individual host (e.g. /24)
tunNet := ip.IP4Net{
IP: sn.IP,
PrefixLen: sm.GetConfig().Network.PrefixLen,
}
// TUN MTU will be smaller b/c of encap (IP+UDP hdrs)
var mtu int
if tepIface.MTU > 0 {
mtu = tepIface.MTU - encapOverhead
} else {
log.Errorf("Failed to determine MTU for %s interface", tepIP)
return
}
err = configureIface(tunName, tunNet, mtu)
if err != nil {
return
}
if ipMasq {
err = setupIpMasq(tunNet.Network(), tunName)
if err != nil {
return
}
}
// all initialized and ready for business
log.Info("UDP encapsulation initialized")
ready(sn, mtu)
fastProxy(sm, tun, conn, tunNet.IP, uint(mtu), port)
}
func configureIface(ifname string, ipn ip.IP4Net, mtu int) error {
iface, err := net.InterfaceByName(ifname)
if err != nil {
log.Error("Failed to lookup interface ", ifname)
return err
}
n := ipn.ToIPNet()
err = netlink.NetworkLinkAddIp(iface, n.IP, n)
if err != nil {
log.Errorf("Failed to add IP address %s to %s: %s", n.IP, ifname, err)
return err
}
err = netlink.NetworkSetMTU(iface, mtu)
if err != nil {
log.Errorf("Failed to set MTU for %s: %v", ifname, err)
return err
}
err = netlink.NetworkLinkUp(iface)
if err != nil {
log.Errorf("Failed to set interface %s to UP state: %s", ifname, err)
return 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.AddRoute(ipn.Network().String(), "", "", ifname)
if err != nil && err != syscall.EEXIST {
log.Errorf("Failed to add route (%s -> %s): %v", ipn.Network().String(), ifname, err)
return err
}
return nil
}
