// Allocate an external port and map it to the interface
func AllocatePort(job *engine.Job) engine.Status {
var (
err error
ip = defaultBindingIP
id = job.Args[0]
hostIP = job.Getenv("HostIP")
hostPort = job.GetenvInt("HostPort")
containerPort = job.GetenvInt("ContainerPort")
proto = job.Getenv("Proto")
network = currentInterfaces[id]
)
if hostIP != "" {
ip = net.ParseIP(hostIP)
}
// host ip, proto, and host port
hostPort, err = portallocator.RequestPort(ip, proto, hostPort)
if err != nil {
return job.Error(err)
}
var (
container net.Addr
host net.Addr
)
if proto == "tcp" {
host = &net.TCPAddr{IP: ip, Port: hostPort}
container = &net.TCPAddr{IP: network.IP, Port: containerPort}
} else {
host = &net.UDPAddr{IP: ip, Port: hostPort}
container = &net.UDPAddr{IP: network.IP, Port: containerPort}
}
if err := portmapper.Map(container, ip, hostPort); err != nil {
portallocator.ReleasePort(ip, proto, hostPort)
return job.Error(err)
}
network.PortMappings = append(network.PortMappings, host)
out := engine.Env{}
out.Set("HostIP", ip.String())
out.SetInt("HostPort", hostPort)
if _, err := out.WriteTo(job.Stdout); err != nil {
return job.Error(err)
}
return engine.StatusOK
}
// Allocate an external port and map it to the interface
func AllocatePort(job *engine.Job) engine.Status {
var (
err error
ip = defaultBindingIP
id = job.Args[0]
hostIP = job.Getenv("HostIP")
origHostPort = job.GetenvInt("HostPort")
containerPort = job.GetenvInt("ContainerPort")
proto = job.Getenv("Proto")
network = currentInterfaces.Get(id)
)
if hostIP != "" {
ip = net.ParseIP(hostIP)
}
var (
hostPort int
container net.Addr
host net.Addr
)
/*
Try up to 10 times to get a port that's not already allocated.
In the event of failure to bind, return the error that portmapper.Map
yields.
*/
for i := 0; i < 10; i++ {
// host ip, proto, and host port
hostPort, err = portallocator.RequestPort(ip, proto, origHostPort)
if err != nil {
return job.Error(err)
}
if proto == "tcp" {
host = &net.TCPAddr{IP: ip, Port: hostPort}
container = &net.TCPAddr{IP: network.IP, Port: containerPort}
} else {
host = &net.UDPAddr{IP: ip, Port: hostPort}
container = &net.UDPAddr{IP: network.IP, Port: containerPort}
}
if err = portmapper.Map(container, ip, hostPort); err == nil {
break
}
job.Logf("Failed to bind %s:%d for container address %s:%d. Trying another port.", ip.String(), hostPort, network.IP.String(), containerPort)
}
if err != nil {
return job.Error(err)
}
network.PortMappings = append(network.PortMappings, host)
out := engine.Env{}
out.Set("HostIP", ip.String())
out.SetInt("HostPort", hostPort)
if _, err := out.WriteTo(job.Stdout); err != nil {
return job.Error(err)
}
return engine.StatusOK
}
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
}