func allocateDaemonPort(addr string) error {
host, port, err := net.SplitHostPort(addr)
if err != nil {
return err
}
intPort, err := strconv.Atoi(port)
if err != nil {
return err
}
var hostIPs []net.IP
if parsedIP := net.ParseIP(host); parsedIP != nil {
hostIPs = append(hostIPs, parsedIP)
} else if hostIPs, err = net.LookupIP(host); err != nil {
return fmt.Errorf("failed to lookup %s address in host specification", host)
}
for _, hostIP := range hostIPs {
if _, err := portallocator.RequestPort(hostIP, "tcp", intPort); err != nil {
return fmt.Errorf("failed to allocate daemon listening port %d (err: %v)", intPort, err)
}
}
return nil
}
func Map(container net.Addr, hostIP net.IP, hostPort int) (net.Addr, error) {
lock.Lock()
defer lock.Unlock()
var (
m *mapping
err error
proto string
allocatedHostPort int
)
// release the port on any error during return.
defer func() {
if err != nil {
portallocator.ReleasePort(hostIP, proto, allocatedHostPort)
}
}()
switch container.(type) {
case *net.TCPAddr:
proto = "tcp"
if allocatedHostPort, err = portallocator.RequestPort(hostIP, proto, hostPort); err != nil {
return nil, err
}
m = &mapping{
proto: proto,
host: &net.TCPAddr{IP: hostIP, Port: allocatedHostPort},
container: container,
}
case *net.UDPAddr:
proto = "udp"
if allocatedHostPort, err = portallocator.RequestPort(hostIP, proto, hostPort); err != nil {
return nil, err
}
m = &mapping{
proto: proto,
host: &net.UDPAddr{IP: hostIP, Port: allocatedHostPort},
container: container,
}
default:
err = ErrUnknownBackendAddressType
return nil, err
}
key := getKey(m.host)
if _, exists := currentMappings[key]; exists {
err = ErrPortMappedForIP
return nil, err
}
containerIP, containerPort := getIPAndPort(m.container)
if err := forward(iptables.Add, m.proto, hostIP, allocatedHostPort, containerIP.String(), containerPort); err != nil {
return nil, err
}
p, err := newProxy(m.host, m.container)
if err != nil {
// need to undo the iptables rules before we return
forward(iptables.Delete, m.proto, hostIP, allocatedHostPort, containerIP.String(), containerPort)
return nil, err
}
m.userlandProxy = p
currentMappings[key] = m
go p.Run()
return m.host, nil
}