func Unmap(host net.Addr) error {
lock.Lock()
defer lock.Unlock()
key := getKey(host)
data, exists := currentMappings[key]
if !exists {
return ErrPortNotMapped
}
data.userlandProxy.Stop()
delete(currentMappings, key)
containerIP, containerPort := getIPAndPort(data.container)
hostIP, hostPort := getIPAndPort(data.host)
if err := forward(iptables.Delete, data.proto, hostIP, hostPort, containerIP.String(), containerPort); err != nil {
return err
}
switch a := host.(type) {
case *net.TCPAddr:
if err := portallocator.ReleasePort(a.IP, "tcp", a.Port); err != nil {
return err
}
case *net.UDPAddr:
if err := portallocator.ReleasePort(a.IP, "udp", a.Port); err != nil {
return err
}
}
return nil
}
func Map(container net.Addr, hostIP net.IP, hostPort int) (host net.Addr, err error) {
lock.Lock()
defer lock.Unlock()
var (
m *mapping
proto string
allocatedHostPort int
proxy UserlandProxy
)
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,
}
proxy = NewProxy(proto, hostIP, allocatedHostPort, container.(*net.TCPAddr).IP, container.(*net.TCPAddr).Port)
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,
}
proxy = NewProxy(proto, hostIP, allocatedHostPort, container.(*net.UDPAddr).IP, container.(*net.UDPAddr).Port)
default:
return nil, ErrUnknownBackendAddressType
}
// release the allocated port on any further error during return.
defer func() {
if err != nil {
portallocator.ReleasePort(hostIP, proto, allocatedHostPort)
}
}()
key := getKey(m.host)
if _, exists := currentMappings[key]; exists {
return nil, ErrPortMappedForIP
}
containerIP, containerPort := getIPAndPort(m.container)
if err := forward(iptables.Add, m.proto, hostIP, allocatedHostPort, containerIP.String(), containerPort); err != nil {
return nil, err
}
m.userlandProxy = proxy
currentMappings[key] = m
if err := proxy.Start(); err != nil {
// need to undo the iptables rules before we return
forward(iptables.Delete, m.proto, hostIP, allocatedHostPort, containerIP.String(), containerPort)
return nil, err
}
return m.host, nil
}