Working UPnP code. Close #16

2026-07-18 19:17:51 +01:00 · 2021-05-06 14:57:40 +02:00
parent eb0afce3f9
commit 5f8f299799
10 changed files with 294 additions and 35 deletions
--- a/Detection.go
+++ b/Detection.go
@@ -171,7 +171,11 @@ func networkChangeMonitor() {
 func networkChangeInterfaceNew(iface net.Interface, addresses []net.Addr) {
 	log.Printf("networkChangeInterfaceNew new interface '%s' (%d IPs)\n", iface.Name, len(addresses))

-	networkStart(iface, addresses)
+	networks := networkStart(iface, addresses)
+
+	for _, network := range networks {
+		go network.upnpAuto()
+	}

 	go nodesDHT.RefreshBuckets(0)
 }
@@ -214,7 +218,11 @@ func networkChangeInterfaceRemove(iface string, addresses []net.Addr) {
 func networkChangeIPNew(iface net.Interface, address net.Addr) {
 	log.Printf("networkChangeIPNew new interface '%s' IP %s\n", iface.Name, address.String())

-	networkStart(iface, []net.Addr{address})
+	networks := networkStart(iface, []net.Addr{address})
+
+	for _, network := range networks {
+		go network.upnpAuto()
+	}

 	go nodesDHT.RefreshBuckets(0)
 }
--- a/Init.go
+++ b/Init.go
@@ -107,7 +107,7 @@ func initNetwork() {
 }

 // networkStart will start the listeners on all the IP addresses for the network
-func networkStart(iface net.Interface, addresses []net.Addr) {
+func networkStart(iface net.Interface, addresses []net.Addr) (networks []*Network) {
 	for _, address := range addresses {
 		net1 := address.(*net.IPNet)

@@ -133,7 +133,11 @@ func networkStart(iface net.Interface, addresses []net.Addr) {
 		addListenAddress(netw.address)

 		log.Printf("Listen on network '%s' UDP %s\n", iface.Name, netw.address.String())
+
+		networks = append(networks, netw)
 	}
+
+	return
 }

 // networkPrepareListen prepares to listen on the given IP address. If port is 0, one is chosen automatically.
@@ -147,7 +151,7 @@ func networkPrepareListen(ipA string, port int) (network *Network, err error) {
 	network.terminateSignal = make(chan interface{})

 	// get the network interface that belongs to the IP
-	if ipA != "0.0.0.0" && ipA != "::" {
+	if !ip.IsUnspecified() { // checks for IPv4 "0.0.0.0" and IPv6 "::"
 		network.iface, network.ipnet = FindInterfaceByIP(ip)
 		if network.iface == nil {
 			return nil, errors.New("error finding the network interface belonging to IP")
--- a/UPnP.go
+++ b/UPnP.go
@@ -0,0 +1,165 @@
+/*
+File Name:  Network UPnP.go
+Copyright:  2021 Peernet s.r.o.
+Author:     Peter Kleissner
+
+Currently only supports IPv4 networks.
+TODO: Limit mapping to X hours. Auto remap upon expiration.
+*/
+
+package core
+
+import (
+	"log"
+	"math/rand"
+	"net"
+	"sync"
+	"time"
+
+	"github.com/PeernetOfficial/core/upnp"
+)
+
+var upnpListInterfaces map[string]struct{}
+var upnpMutex sync.RWMutex
+
+func startUPnP() {
+	upnpListInterfaces = make(map[string]struct{})
+
+	if config.PortForward > 0 {
+		config.EnableUPnP = false
+	}
+	if !config.EnableUPnP {
+		return
+	}
+
+	for _, network := range networks4 {
+		go network.upnpAuto()
+	}
+}
+
+// upnpIsEligible checks if the network is eligible for UPnP
+func (network *Network) upnpIsEligible() bool {
+	// No link-local addresses. 169.254.*.*
+	// No loopback.
+	if network.address.IP.IsLinkLocalUnicast() || network.address.IP.IsLoopback() {
+		return false
+	}
+
+	// The network interface must be known which indicates that the IP address is NOT a wildcard.
+	// Port forwarding requires to specify a local IP. In case of listening on a wildcard that would not be known and guessing (looking at you btcd) is not a solution.
+	if network.iface == nil {
+		return false
+	}
+
+	return true
+}
+
+// upnpAuto runs a UPnP daemon to forward the port, refresh the forwarding and continuously monitor if the forwarding remains valid.
+func (network *Network) upnpAuto() {
+	if !config.EnableUPnP || !network.upnpIsEligible() {
+		return
+	}
+
+	// Only allow 1 UPnP worker at a time.
+	upnpMutex.Lock()
+	defer upnpMutex.Unlock()
+
+	// If there is already a running UPnP on the adapter, skip.
+	if _, ok := upnpListInterfaces[network.GetAdapterName()]; ok {
+		return
+	}
+
+	nat, err := upnp.Discover(network.address.IP)
+	if err != nil {
+		return
+	}
+
+	network.nat = nat
+
+	externalIP, err := nat.GetExternalAddress()
+	if err != nil {
+		return
+	}
+
+	network.ipExternal = externalIP
+
+	if err := network.upnpTryPortForward(); err != nil {
+		return
+	}
+
+	upnpListInterfaces[network.GetAdapterName()] = struct{}{}
+
+	go network.upnpMonitorPortForward()
+}
+
+// upnpMonitorPortForward monitors the port forwarding status
+func (network *Network) upnpMonitorPortForward() {
+	ticker := time.NewTicker(time.Second * 10)
+
+monitorLoop:
+	for {
+		select {
+		case <-ticker.C:
+		case <-network.terminateSignal:
+			// Remove port mapping. Note that in case the network is unavailable this is likely to fail.
+			network.nat.DeletePortMapping("UDP", network.portExternal)
+
+			network.portExternal = 0
+			network.ipExternal = net.IP{}
+
+			break monitorLoop
+		}
+
+		// 3 tries
+		var err error
+		for n := 0; n < 3; n++ {
+			if err = network.upnpValidate(); err == nil {
+				continue monitorLoop
+			}
+		}
+
+		// invalid :(
+		log.Printf("upnpAuto port forwarding invalidated for local IP %s (adapter %s) external IP %s port %d", network.address.String(), network.iface.Name, network.ipExternal.String(), network.portExternal)
+
+		network.portExternal = 0
+		network.ipExternal = net.IP{}
+
+		break
+	}
+
+	ticker.Stop()
+
+	upnpMutex.Lock()
+	delete(upnpListInterfaces, network.GetAdapterName())
+	upnpMutex.Unlock()
+}
+
+func (network *Network) upnpTryPortForward() (err error) {
+	// Try forwarding the port. First to the same one listening, otherwise random.
+	mappedExternalPort, err := network.nat.AddPortMapping("UDP", network.address.IP, uint16(network.address.Port), uint16(network.address.Port), "Peernet", 0)
+	if err != nil {
+		mappedExternalPort, err = network.nat.AddPortMapping("UDP", network.address.IP, uint16(network.address.Port), uint16(randInt(1024, 65535)), "Peernet", 0)
+	}
+	if err != nil {
+		return err
+	}
+
+	// validate
+	if err := network.upnpValidate(); err != nil {
+		return err
+	}
+
+	// valid!
+	network.portExternal = mappedExternalPort
+
+	return nil
+}
+
+func randInt(min int, max int) int {
+	return min + rand.Intn(max-min)
+}
+
+func (network *Network) upnpValidate() (err error) {
+	// TODO: Send special message which validates the UPnP mapping
+	return nil
+}
--- a/Network.go
+++ b/Network.go
@@ -13,6 +13,8 @@ import (
 	"sync"
 	"sync/atomic"
 	"time"
+
+	"github.com/PeernetOfficial/core/upnp"
 )

 // Network is a connection adapter through one network interface (adapter).
@@ -27,6 +29,8 @@ type Network struct {
 	broadcastSocket net.PacketConn   // Broadcast socket, IPv4 only.
 	broadcastIPv4   []net.IP         // Broadcast IPs, IPv4 only.
 	portExternal    uint16           // External port. 0 if not known.
+	ipExternal      net.IP           // External IP of the network. Usually not known.
+	nat             upnp.NAT         // UPnP: NAT information
 	isTerminated    bool             // If true, the network was signaled for termination
 	terminateSignal chan interface{} // gets closed on termination signal, can be used in select via "case _ = <- network.terminateSignal:"
 	sync.RWMutex                     // for sychronized closing
--- a/Peernet.go
+++ b/Peernet.go
@@ -26,4 +26,5 @@ func Connect() {
 	go autoPingAll()
 	go networkChangeMonitor()
 	go autoBucketRefresh()
+	go startUPnP()
 }
--- a/go.mod
+++ b/go.mod
@@ -3,7 +3,7 @@ module github.com/PeernetOfficial/core
 go 1.16

 require (
-	github.com/PeernetOfficial/core/dht v0.0.0-20210425014452-611dfa3b1ce9
+	github.com/PeernetOfficial/core/dht v0.0.0-20210506124834-e929d6ba2f22
 	github.com/btcsuite/btcd v0.21.0-beta.0.20210401013323-36a96f6a0025
 	github.com/pkg/errors v0.9.1
 	golang.org/x/crypto v0.0.0-20210415154028-4f45737414dc
--- a/go.sum
+++ b/go.sum
@@ -1,5 +1,5 @@
-github.com/PeernetOfficial/core/dht v0.0.0-20210425014452-611dfa3b1ce9 h1:kcjoWZl9GZ9uSajS6t0tiKDpaatUQ64tl3OqXPc+YsY=
-github.com/PeernetOfficial/core/dht v0.0.0-20210425014452-611dfa3b1ce9/go.mod h1:sb2H21VIVTohCXVrDFo/Skl2tN8Yzba+MXSS6NgCYXw=
+github.com/PeernetOfficial/core/dht v0.0.0-20210506124834-e929d6ba2f22 h1:FHBHtQR3ShxuxkG8tgE4ER86UmbNdXam/I1irdiusqg=
+github.com/PeernetOfficial/core/dht v0.0.0-20210506124834-e929d6ba2f22/go.mod h1:sb2H21VIVTohCXVrDFo/Skl2tN8Yzba+MXSS6NgCYXw=
 github.com/aead/siphash v1.0.1/go.mod h1:Nywa3cDsYNNK3gaciGTWPwHt0wlpNV15vwmswBAUSII=
 github.com/btcsuite/btcd v0.20.1-beta/go.mod h1:wVuoA8VJLEcwgqHBwHmzLRazpKxTv13Px/pDuV7OomQ=
 github.com/btcsuite/btcd v0.21.0-beta.0.20210401013323-36a96f6a0025 h1:aoVqvZk4mLyF3WZbqEVPq+vXnwL2wekZg4P4mjYJNLs=
--- a/upnp/README.md
+++ b/upnp/README.md
@@ -3,3 +3,18 @@
 There are 2 reference implementations which both are based on 'Taipei Torrent'. This UPnP code is a fork mostly from the btcd one with some changes forked from tendermint.
 * https://github.com/btcsuite/btcd/blob/master/upnp.go
 * https://github.com/tendermint/tendermint/tree/master/p2p/upnp
+
+This library supports only IPv4 UPnP currently. The IPv6 UPnP protocol is specified here: http://upnp.org/specs/arch/UPnP-arch-AnnexAIPv6-v1.pdf
+
+## Special Cases
+
+FritzBox:
+* Users must manually enable port sharing for the host. Otherwise the router returns XML error code 606.
+* If the internal port is already forwarded under a different external port, error code 718 is returned.
+* If the internal port is already forwarded under the same external port, it does not return an error.
+
+## Troubleshooting
+
+Using Wireshark to intercept the UPnP request and response can help.
+
+For Windows there is a UPnP tool here http://miniupnp.free.fr/files/. The tool supports listing existing mappings which is an interesting functionality. It would make sense to implement the list function to delete or reuse any existing mappings.
--- a/upnp/UPnP.go
+++ b/upnp/UPnP.go
@@ -17,31 +17,31 @@ import (
 	"time"
 )

-// NAT is an interface representing a NAT traversal options for example UPNP or
-// NAT-PMP. It provides methods to query and manipulate this traversal to allow
-// access to services.
+// NAT is an interface representing a NAT traversal options for example UPNP or NAT-PMP.
+// It provides methods to query and manipulate this traversal to allow access to services.
 type NAT interface {
 	// Get the external address from outside the NAT.
 	GetExternalAddress() (addr net.IP, err error)
 	// Add a port mapping for protocol ("udp" or "tcp") from external port to internal port with description lasting for timeout.
-	AddPortMapping(protocol string, internalIP net.IP, externalPort, internalPort int, description string, timeout int) (mappedExternalPort int, err error)
+	AddPortMapping(protocol string, internalIP net.IP, internalPort, externalPort uint16, description string, timeout int) (mappedExternalPort uint16, err error)
 	// Remove a previously added port mapping from external port to internal port.
-	DeletePortMapping(protocol string, externalPort, internalPort int) (err error)
+	DeletePortMapping(protocol string, externalPort uint16) (err error)
 }

 type upnpNAT struct {
 	serviceURL string
 	urnDomain  string
+	localIP    net.IP
 }

-// Discover searches the local network for a UPnP router returning a NAT
-// for the network if so, nil if not.
-func Discover() (nat NAT, err error) {
+// Discover searches the local network for a UPnP router returning a NAT for the network if so, nil if not.
+// Socket must be an active local socket.
+func Discover(localIP net.IP) (nat NAT, err error) {
 	ssdp, err := net.ResolveUDPAddr("udp4", "239.255.255.250:1900")
 	if err != nil {
 		return
 	}
-	conn, err := net.ListenPacket("udp4", ":0")
+	conn, err := net.ListenPacket("udp4", net.JoinHostPort(localIP.String(), "0")) // use a random port
 	if err != nil {
 		return
 	}
@@ -97,11 +97,11 @@ func Discover() (nat NAT, err error) {
 			}
 			locURL := strings.TrimSpace(loc[0:endIndex])
 			var serviceURL, urnDomain string
-			serviceURL, urnDomain, err = getServiceURL(locURL)
+			serviceURL, urnDomain, err = getServiceURL(localIP, locURL)
 			if err != nil {
 				return
 			}
-			nat = &upnpNAT{serviceURL: serviceURL, urnDomain: urnDomain}
+			nat = &upnpNAT{serviceURL: serviceURL, urnDomain: urnDomain, localIP: localIP}
 			return
 		}
 	}
@@ -185,8 +185,25 @@ func getChildService(d *device, serviceType string) *service {

 // getServiceURL parses the xml description at the given root url to find the
 // url for the WANIPConnection service to be used for port forwarding.
-func getServiceURL(rootURL string) (url, urnDomain string, err error) {
-	r, err := http.Get(rootURL)
+func getServiceURL(localIP net.IP, rootURL string) (url, urnDomain string, err error) {
+
+	webclient := &http.Client{
+		Transport: &http.Transport{
+			Proxy: nil,
+			DialContext: (&net.Dialer{
+				LocalAddr: &net.TCPAddr{
+					IP: localIP,
+				},
+				Timeout:   3 * time.Second,
+				DualStack: true,
+			}).DialContext,
+			TLSHandshakeTimeout:   3 * time.Second,
+			ExpectContinueTimeout: 1 * time.Second,
+		},
+		Timeout: 3 * time.Second,
+	}
+
+	r, err := webclient.Get(rootURL)
 	if err != nil {
 		return
 	}
@@ -259,7 +276,7 @@ type soapEnvelope struct {
 // soapRequests performs a soap request with the given parameters and returns
 // the xml replied stripped of the soap headers. in the case that the request is
 // unsuccessful the an error is returned.
-func soapRequest(url, function, message, domain string) (replyXML []byte, err error) {
+func (n *upnpNAT) soapRequest(url, function, message, domain string) (replyXML []byte, err error) {
 	fullMessage := "<?xml version=\"1.0\" ?>" +
 		"<s:Envelope xmlns:s=\"http://schemas.xmlsoap.org/soap/envelope/\" s:encodingStyle=\"http://schemas.xmlsoap.org/soap/encoding/\">\r\n" +
 		"<s:Body>" + message + "</s:Body></s:Envelope>"
@@ -275,7 +292,23 @@ func soapRequest(url, function, message, domain string) (replyXML []byte, err er
 	req.Header.Set("Cache-Control", "no-cache")
 	req.Header.Set("Pragma", "no-cache")

-	r, err := http.DefaultClient.Do(req)
+	webclient := &http.Client{
+		Transport: &http.Transport{
+			Proxy: nil,
+			DialContext: (&net.Dialer{
+				LocalAddr: &net.TCPAddr{
+					IP: n.localIP,
+				},
+				Timeout:   3 * time.Second,
+				DualStack: true,
+			}).DialContext,
+			TLSHandshakeTimeout:   3 * time.Second,
+			ExpectContinueTimeout: 1 * time.Second,
+		},
+		Timeout: 3 * time.Second,
+	}
+
+	r, err := webclient.Do(req)
 	if err != nil {
 		return nil, err
 	}
@@ -307,7 +340,7 @@ type getExternalIPAddressResponse struct {
 // from the UPnP router.
 func (n *upnpNAT) GetExternalAddress() (addr net.IP, err error) {
 	message := "<u:GetExternalIPAddress xmlns:u=\"urn:" + n.urnDomain + ":service:WANIPConnection:1\">\r\n</u:GetExternalIPAddress>"
-	response, err := soapRequest(n.serviceURL, "GetExternalIPAddress", message, n.urnDomain)
+	response, err := n.soapRequest(n.serviceURL, "GetExternalIPAddress", message, n.urnDomain)
 	if err != nil {
 		return nil, err
 	}
@@ -325,22 +358,25 @@ func (n *upnpNAT) GetExternalAddress() (addr net.IP, err error) {
 	return addr, nil
 }

-// AddPortMapping implements the NAT interface by setting up a port forwarding
-// from the UPnP router to the local machine with the given ports and protocol.
-func (n *upnpNAT) AddPortMapping(protocol string, internalIP net.IP, externalPort, internalPort int, description string, timeout int) (mappedExternalPort int, err error) {
+// AddPortMapping forwards a port at the UPnP router to the specified IP address and port. Lease duration is in seconds.
+// FritzBox routers: Forwarding an already forwarded port results in no error. If the internal port is already forwarded under a different external port, error code 718 is returned in XML.
+func (n *upnpNAT) AddPortMapping(protocol string, internalIP net.IP, internalPort, externalPort uint16, description string, leaseDuration int) (mappedExternalPort uint16, err error) {
 	// A single concatenation would break ARM compilation.
 	message := "<u:AddPortMapping xmlns:u=\"urn:" + n.urnDomain + ":service:WANIPConnection:1\">\r\n" +
-		"<NewRemoteHost></NewRemoteHost><NewExternalPort>" + strconv.Itoa(externalPort)
+		"<NewRemoteHost></NewRemoteHost><NewExternalPort>" + strconv.Itoa(int(externalPort))
 	message += "</NewExternalPort><NewProtocol>" + strings.ToUpper(protocol) + "</NewProtocol>"
-	message += "<NewInternalPort>" + strconv.Itoa(internalPort) + "</NewInternalPort>" +
+	message += "<NewInternalPort>" + strconv.Itoa(int(internalPort)) + "</NewInternalPort>" +
 		"<NewInternalClient>" + internalIP.String() + "</NewInternalClient>" +
 		"<NewEnabled>1</NewEnabled><NewPortMappingDescription>"
 	message += description +
-		"</NewPortMappingDescription><NewLeaseDuration>" + strconv.Itoa(timeout) +
+		"</NewPortMappingDescription><NewLeaseDuration>" + strconv.Itoa(leaseDuration) +
 		"</NewLeaseDuration></u:AddPortMapping>"

-	response, err := soapRequest(n.serviceURL, "AddPortMapping", message, n.urnDomain)
+	response, err := n.soapRequest(n.serviceURL, "AddPortMapping", message, n.urnDomain)
 	if err != nil {
+		// If UPnP is not allowed for the host (with FritzBox routers the user must manually enable it), the router returns "<errorCode>606</errorCode>"
+		// in the XML response with HTTP code 500 Internal Server Error.
+		// If the internal port is already forwarded under a different external port, error code 718 is returned in XML.
 		return
 	}

@@ -352,16 +388,15 @@ func (n *upnpNAT) AddPortMapping(protocol string, internalIP net.IP, externalPor
 	return mappedExternalPort, err
 }

-// DeletePortMapping implements the NAT interface by removing up a port forwarding
-// from the UPnP router to the local machine with the given ports and.
-func (n *upnpNAT) DeletePortMapping(protocol string, externalPort, internalPort int) (err error) {
+// DeletePortMapping deletes a port mapping.
+func (n *upnpNAT) DeletePortMapping(protocol string, externalPort uint16) (err error) {

 	message := "<u:DeletePortMapping xmlns:u=\"urn:" + n.urnDomain + ":service:WANIPConnection:1\">\r\n" +
-		"<NewRemoteHost></NewRemoteHost><NewExternalPort>" + strconv.Itoa(externalPort) +
+		"<NewRemoteHost></NewRemoteHost><NewExternalPort>" + strconv.Itoa(int(externalPort)) +
 		"</NewExternalPort><NewProtocol>" + strings.ToUpper(protocol) + "</NewProtocol>" +
 		"</u:DeletePortMapping>"

-	response, err := soapRequest(n.serviceURL, "DeletePortMapping", message, n.urnDomain)
+	response, err := n.soapRequest(n.serviceURL, "DeletePortMapping", message, n.urnDomain)
 	if err != nil {
 		return
 	}
--- a/upnp/UPnP_test.go
+++ b/upnp/UPnP_test.go
@@ -0,0 +1,27 @@
+// Small code for manual tests/development.
+
+package upnp
+
+import (
+	"fmt"
+	"net"
+	"testing"
+)
+
+func TestUPnP(t *testing.T) {
+	localIP := net.ParseIP("0.0.0.0")
+
+	nat, err := Discover(localIP)
+	if err != nil {
+		fmt.Printf("%v\n", err)
+		return
+	}
+
+	addr, err := nat.GetExternalAddress()
+	if err != nil {
+		fmt.Printf("%v\n", err)
+		return
+	}
+
+	fmt.Printf("%s\n", addr.String())
+}