func DeleteInterfaceIp(name string, rawIp string) error {
iface, err := net.InterfaceByName(name)
if err != nil {
return err
}
ip, ipNet, err := net.ParseCIDR(rawIp)
if err != nil {
return err
}
return netlink.NetworkLinkDelIp(iface, ip, ipNet)
}
// ConfigureNetworking is called once during host startup and sets up the local
// bridge and forwarding rules for containers.
func (l *LibcontainerBackend) ConfigureNetworking(config *host.NetworkConfig) error {
log := l.logger.New("fn", "ConfigureNetworking")
var err error
l.bridgeAddr, l.bridgeNet, err = net.ParseCIDR(config.Subnet)
if err != nil {
return err
}
l.ipalloc.RequestIP(l.bridgeNet, l.bridgeAddr)
err = netlink.CreateBridge(l.bridgeName, false)
bridgeExists := os.IsExist(err)
if err != nil && !bridgeExists {
return err
}
bridge, err := net.InterfaceByName(l.bridgeName)
if err != nil {
return err
}
if !bridgeExists {
// We need to explicitly assign the MAC address to avoid it changing to a lower value
// See: https://github.com/flynn/flynn/issues/223
b := random.Bytes(5)
bridgeMAC := fmt.Sprintf("fe:%02x:%02x:%02x:%02x:%02x", b[0], b[1], b[2], b[3], b[4])
if err := netlink.NetworkSetMacAddress(bridge, bridgeMAC); err != nil {
return err
}
}
currAddrs, err := bridge.Addrs()
if err != nil {
return err
}
setIP := true
for _, addr := range currAddrs {
ip, net, _ := net.ParseCIDR(addr.String())
if ip.Equal(l.bridgeAddr) && net.String() == l.bridgeNet.String() {
setIP = false
} else {
if err := netlink.NetworkLinkDelIp(bridge, ip, net); err != nil {
return err
}
}
}
if setIP {
if err := netlink.NetworkLinkAddIp(bridge, l.bridgeAddr, l.bridgeNet); err != nil {
return err
}
}
if err := netlink.NetworkLinkUp(bridge); err != nil {
return err
}
// enable IP forwarding
if err := ioutil.WriteFile("/proc/sys/net/ipv4/ip_forward", []byte("1\n"), 0644); err != nil {
return err
}
// Set up iptables for outbound traffic masquerading from containers to the
// rest of the network.
if err := iptables.EnableOutboundNAT(l.bridgeName, l.bridgeNet.String()); err != nil {
return err
}
// Read DNS config, discoverd uses the nameservers
dnsConf, err := dns.ClientConfigFromFile("/etc/resolv.conf")
if err != nil {
return err
}
config.Resolvers = dnsConf.Servers
// Write a resolv.conf to be bind-mounted into containers pointing at the
// future discoverd DNS listener
if err := os.MkdirAll("/etc/flynn", 0755); err != nil {
return err
}
var resolvSearch string
if len(dnsConf.Search) > 0 {
resolvSearch = fmt.Sprintf("search %s\n", strings.Join(dnsConf.Search, " "))
}
if err := ioutil.WriteFile("/etc/flynn/resolv.conf", []byte(fmt.Sprintf("%snameserver %s\n", resolvSearch, l.bridgeAddr.String())), 0644); err != nil {
return err
}
l.resolvConf = "/etc/flynn/resolv.conf"
// Allocate IPs for running jobs
l.containersMtx.Lock()
defer l.containersMtx.Unlock()
for _, container := range l.containers {
if !container.job.Config.HostNetwork {
if _, err := l.ipalloc.RequestIP(l.bridgeNet, container.IP); err != nil {
log.Error("error requesting ip", "job.id", container.job.ID, "err", err)
}
}
}
close(l.networkConfigured)
return nil
}
// UnsetLinkIp configures the link's IP address.
// It is equivalent of running: ip address del ${address}/${mask} dev ${interface name}
func (l *Link) UnsetLinkIp(ip net.IP, network *net.IPNet) error {
return netlink.NetworkLinkDelIp(l.NetInterface(), ip, network)
}