Implemented support for UPnP

ethereum.go

@@ -8,6 +8,7 @@ import (
 	"github.com/ethereum/ethwire-go"
 	"log"
 	"net"
+	"strconv"
 	"sync"
 	"sync/atomic"
 	"time"
@@ -29,6 +30,7 @@ const (
 type Ethereum struct {
 	// Channel for shutting down the ethereum
 	shutdownChan chan bool
+	quit         chan bool
 	// DB interface
 	//db *ethdb.LDBDatabase
 	db *ethdb.MemDatabase
@@ -48,6 +50,8 @@ type Ethereum struct {
 
 	// Capabilities for outgoing peers
 	serverCaps Caps
+
+	nat NAT
 }
 
 func New(caps Caps) (*Ethereum, error) {
@@ -57,15 +61,30 @@ func New(caps Caps) (*Ethereum, error) {
 		return nil, err
 	}
 
+	/*
+		gateway := net.ParseIP("192.168.192.1")
+		nat := NewNatPMP(gateway)
+		port, err := nat.AddPortMapping("tcp", 30303, 30303, "", 60)
+		log.Println(port, err)
+	*/
+
+	nat, err := Discover()
+	if err != nil {
+		log.Println("UPnP failed", err)
+		return nil, err
+	}
+
 	ethutil.Config.Db = db
 
 	nonce, _ := ethutil.RandomUint64()
 	ethereum := &Ethereum{
 		shutdownChan: make(chan bool),
+		quit:         make(chan bool),
 		db:           db,
 		peers:        list.New(),
 		Nonce:        nonce,
 		serverCaps:   caps,
+		nat:          nat,
 	}
 	ethereum.TxPool = ethchain.NewTxPool()
 	ethereum.TxPool.Speaker = ethereum
@@ -217,6 +236,8 @@ func (s *Ethereum) Start() {
 		go s.peerHandler(ln)
 	}
 
+	go s.upnpUpdateThread()
+
 	// Start the reaping processes
 	go s.ReapDeadPeerHandler()
 
@@ -245,6 +266,8 @@ func (s *Ethereum) Stop() {
 		p.Stop()
 	})
 
+	close(s.quit)
+
 	s.shutdownChan <- true
 
 	s.TxPool.Stop()
@@ -254,3 +277,42 @@ func (s *Ethereum) Stop() {
 func (s *Ethereum) WaitForShutdown() {
 	<-s.shutdownChan
 }
+
+func (s *Ethereum) upnpUpdateThread() {
+	// Go off immediately to prevent code duplication, thereafter we renew
+	// lease every 15 minutes.
+	timer := time.NewTimer(0 * time.Second)
+	lport, _ := strconv.ParseInt("30303", 10, 16)
+	first := true
+out:
+	for {
+		select {
+		case <-timer.C:
+			listenPort, err := s.nat.AddPortMapping("TCP", int(lport), int(lport), "eth listen port", 20*60)
+			if err != nil {
+				log.Println("can't add UPnP port mapping:", err)
+				break out
+			}
+			if first && err == nil {
+				externalip, err := s.nat.GetExternalAddress()
+				if err != nil {
+					log.Println("UPnP can't get external address:", err)
+					continue out
+				}
+				log.Println("Successfully bound via UPnP to", externalip, listenPort)
+				first = false
+			}
+			timer.Reset(time.Minute * 15)
+		case <-s.quit:
+			break out
+		}
+	}
+
+	timer.Stop()
+
+	if err := s.nat.DeletePortMapping("TCP", int(lport), int(lport)); err != nil {
+		log.Println("unable to remove UPnP port mapping:", err)
+	} else {
+		log.Println("succesfully disestablished UPnP port mapping")
+	}
+}

nat.go

+package eth
+
+import (
+	"net"
+)
+
+// protocol is either "udp" or "tcp"
+type NAT interface {
+	GetExternalAddress() (addr net.IP, err error)
+	AddPortMapping(protocol string, externalPort, internalPort int, description string, timeout int) (mappedExternalPort int, err error)
+	DeletePortMapping(protocol string, externalPort, internalPort int) (err error)
+}

natpmp.go

+package eth
+
+import (
+	natpmp "code.google.com/p/go-nat-pmp"
+	"fmt"
+	"net"
+)
+
+// Adapt the NAT-PMP protocol to the NAT interface
+
+// TODO:
+//  + Register for changes to the external address.
+//  + Re-register port mapping when router reboots.
+//  + A mechanism for keeping a port mapping registered.
+
+type natPMPClient struct {
+	client *natpmp.Client
+}
+
+func NewNatPMP(gateway net.IP) (nat NAT) {
+	return &natPMPClient{natpmp.NewClient(gateway)}
+}
+
+func (n *natPMPClient) GetExternalAddress() (addr net.IP, err error) {
+	response, err := n.client.GetExternalAddress()
+	if err != nil {
+		return
+	}
+	ip := response.ExternalIPAddress
+	addr = net.IPv4(ip[0], ip[1], ip[2], ip[3])
+	return
+}
+
+func (n *natPMPClient) AddPortMapping(protocol string, externalPort, internalPort int,
+	description string, timeout int) (mappedExternalPort int, err error) {
+	if timeout <= 0 {
+		err = fmt.Errorf("timeout must not be <= 0")
+		return
+	}
+	// Note order of port arguments is switched between our AddPortMapping and the client's AddPortMapping.
+	response, err := n.client.AddPortMapping(protocol, internalPort, externalPort, timeout)
+	if err != nil {
+		return
+	}
+	mappedExternalPort = int(response.MappedExternalPort)
+	return
+}
+
+func (n *natPMPClient) DeletePortMapping(protocol string, externalPort, internalPort int) (err error) {
+	// To destroy a mapping, send an add-port with
+	// an internalPort of the internal port to destroy, an external port of zero and a time of zero.
+	_, err = n.client.AddPortMapping(protocol, internalPort, 0, 0)
+	return
+}