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package portmapper
import (
"errors"
"fmt"
"github.com/dotcloud/docker/pkg/iptables"
"github.com/dotcloud/docker/pkg/proxy"
"net"
"sync"
)
type mapping struct {
proto string
userlandProxy proxy.Proxy
host net.Addr
container net.Addr
}
var (
chain *iptables.Chain
lock sync.Mutex
// udp:ip:port
currentMappings = make(map[string]*mapping)
newProxy = proxy.NewProxy
)
var (
ErrUnknownBackendAddressType = errors.New("unknown container address type not supported")
ErrPortMappedForIP = errors.New("port is already mapped to ip")
ErrPortNotMapped = errors.New("port is not mapped")
)
func SetIptablesChain(c *iptables.Chain) {
chain = c
}
func Map(container net.Addr, hostIP net.IP, hostPort int) error {
lock.Lock()
defer lock.Unlock()
var m *mapping
switch container.(type) {
case *net.TCPAddr:
m = &mapping{
proto: "tcp",
host: &net.TCPAddr{IP: hostIP, Port: hostPort},
container: container,
}
case *net.UDPAddr:
m = &mapping{
proto: "udp",
host: &net.UDPAddr{IP: hostIP, Port: hostPort},
container: container,
}
default:
return ErrUnknownBackendAddressType
}
key := getKey(m.host)
if _, exists := currentMappings[key]; exists {
return ErrPortMappedForIP
}
containerIP, containerPort := getIPAndPort(m.container)
if err := forward(iptables.Add, m.proto, hostIP, hostPort, containerIP.String(), containerPort); err != nil {
return err
}
p, err := newProxy(m.host, m.container)
if err != nil {
// need to undo the iptables rules before we reutrn
forward(iptables.Delete, m.proto, hostIP, hostPort, containerIP.String(), containerPort)
return err
}
m.userlandProxy = p
currentMappings[key] = m
go p.Run()
return nil
}
func Unmap(host net.Addr) error {
lock.Lock()
defer lock.Unlock()
key := getKey(host)
data, exists := currentMappings[key]
if !exists {
return ErrPortNotMapped
}
data.userlandProxy.Close()
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
}
return nil
}
func getKey(a net.Addr) string {
switch t := a.(type) {
case *net.TCPAddr:
return fmt.Sprintf("%s:%d/%s", t.IP.String(), t.Port, "tcp")
case *net.UDPAddr:
return fmt.Sprintf("%s:%d/%s", t.IP.String(), t.Port, "udp")
}
return ""
}
func getIPAndPort(a net.Addr) (net.IP, int) {
switch t := a.(type) {
case *net.TCPAddr:
return t.IP, t.Port
case *net.UDPAddr:
return t.IP, t.Port
}
return nil, 0
}
func forward(action iptables.Action, proto string, sourceIP net.IP, sourcePort int, containerIP string, containerPort int) error {
if chain == nil {
return nil
}
return chain.Forward(action, sourceIP, sourcePort, proto, containerIP, containerPort)
}
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