p2p/nat: new package for port mapping stuff
I have verified that UPnP and NAT-PMP work against an older version of the MiniUPnP daemon running on pfSense. This code is kind of hard to test automatically.
This commit is contained in:
Felix Lange
parent
4242b05462
commit
1543833ca0
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@ -0,0 +1,235 @@
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// Package nat provides access to common port mapping protocols.
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package nat
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import (
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"errors"
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"fmt"
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"net"
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"strings"
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"sync"
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"time"
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"github.com/ethereum/go-ethereum/logger"
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"github.com/jackpal/go-nat-pmp"
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)
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var log = logger.NewLogger("P2P NAT")
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// An implementation of nat.Interface can map local ports to ports
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// accessible from the Internet.
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type Interface interface {
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// These methods manage a mapping between a port on the local
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// machine to a port that can be connected to from the internet.
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//
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// protocol is "UDP" or "TCP". Some implementations allow setting
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// a display name for the mapping. The mapping may be removed by
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// the gateway when its lifetime ends.
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AddMapping(protocol string, extport, intport int, name string, lifetime time.Duration) error
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DeleteMapping(protocol string, extport, intport int) error
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// This method should return the external (Internet-facing)
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// address of the gateway device.
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ExternalIP() (net.IP, error)
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// Should return name of the method. This is used for logging.
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String() string
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}
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// Parse parses a NAT interface description.
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// The following formats are currently accepted.
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// Note that mechanism names are not case-sensitive.
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//
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// "" or "none" return nil
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// "extip:77.12.33.4" will assume the local machine is reachable on the given IP
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// "any" uses the first auto-detected mechanism
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// "upnp" uses the Universal Plug and Play protocol
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// "pmp" uses NAT-PMP with an auto-detected gateway address
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// "pmp:192.168.0.1" uses NAT-PMP with the given gateway address
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func Parse(spec string) (Interface, error) {
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var (
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parts = strings.SplitN(spec, ":", 2)
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mech = strings.ToLower(parts[0])
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ip net.IP
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)
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if len(parts) > 1 {
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ip = net.ParseIP(parts[1])
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if ip == nil {
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return nil, errors.New("invalid IP address")
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}
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}
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switch mech {
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case "", "none", "off":
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return nil, nil
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case "any", "auto", "on":
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return Any(), nil
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case "extip", "ip":
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if ip == nil {
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return nil, errors.New("missing IP address")
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}
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return ExtIP(ip), nil
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case "upnp":
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return UPnP(), nil
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case "pmp", "natpmp", "nat-pmp":
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return PMP(ip), nil
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default:
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return nil, fmt.Errorf("unknown mechanism %q", parts[0])
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}
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}
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const (
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mapTimeout = 20 * time.Minute
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mapUpdateInterval = 15 * time.Minute
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)
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// Map adds a port mapping on m and keeps it alive until c is closed.
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// This function is typically invoked in its own goroutine.
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func Map(m Interface, c chan struct{}, protocol string, extport, intport int, name string) {
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refresh := time.NewTimer(mapUpdateInterval)
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defer func() {
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refresh.Stop()
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log.Debugf("Deleting port mapping: %s %d -> %d (%s) using %s\n", protocol, extport, intport, name, m)
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m.DeleteMapping(protocol, extport, intport)
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}()
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log.Debugf("add mapping: %s %d -> %d (%s) using %s\n", protocol, extport, intport, name, m)
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if err := m.AddMapping(protocol, intport, extport, name, mapTimeout); err != nil {
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log.Errorf("mapping error: %v\n", err)
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}
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for {
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select {
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case _, ok := <-c:
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if !ok {
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return
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}
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case <-refresh.C:
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log.DebugDetailf("refresh mapping: %s %d -> %d (%s) using %s\n", protocol, extport, intport, name, m)
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if err := m.AddMapping(protocol, intport, extport, name, mapTimeout); err != nil {
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log.Errorf("mapping error: %v\n", err)
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}
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refresh.Reset(mapUpdateInterval)
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}
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}
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}
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// ExtIP assumes that the local machine is reachable on the given
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// external IP address, and that any required ports were mapped manually.
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// Mapping operations will not return an error but won't actually do anything.
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func ExtIP(ip net.IP) Interface {
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if ip == nil {
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panic("IP must not be nil")
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}
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return extIP(ip)
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}
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type extIP net.IP
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func (n extIP) ExternalIP() (net.IP, error) { return net.IP(n), nil }
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func (n extIP) String() string { return fmt.Sprintf("ExtIP(%v)", net.IP(n)) }
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// These do nothing.
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func (extIP) AddMapping(string, int, int, string, time.Duration) error { return nil }
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func (extIP) DeleteMapping(string, int, int) error { return nil }
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// Any returns a port mapper that tries to discover any supported
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// mechanism on the local network.
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func Any() Interface {
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// TODO: attempt to discover whether the local machine has an
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// Internet-class address. Return ExtIP in this case.
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return startautodisc("UPnP or NAT-PMP", func() Interface {
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found := make(chan Interface, 2)
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go func() { found <- discoverUPnP() }()
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go func() { found <- discoverPMP() }()
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for i := 0; i < cap(found); i++ {
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if c := <-found; c != nil {
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return c
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}
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}
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return nil
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})
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}
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// UPnP returns a port mapper that uses UPnP. It will attempt to
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// discover the address of your router using UDP broadcasts.
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func UPnP() Interface {
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return startautodisc("UPnP", discoverUPnP)
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}
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// PMP returns a port mapper that uses NAT-PMP. The provided gateway
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// address should be the IP of your router. If the given gateway
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// address is nil, PMP will attempt to auto-discover the router.
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func PMP(gateway net.IP) Interface {
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if gateway != nil {
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return &pmp{gw: gateway, c: natpmp.NewClient(gateway)}
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}
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return startautodisc("NAT-PMP", discoverPMP)
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}
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// autodisc represents a port mapping mechanism that is still being
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// auto-discovered. Calls to the Interface methods on this type will
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// wait until the discovery is done and then call the method on the
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// discovered mechanism.
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//
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// This type is useful because discovery can take a while but we
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// want return an Interface value from UPnP, PMP and Auto immediately.
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type autodisc struct {
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what string
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done <-chan Interface
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mu sync.Mutex
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found Interface
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}
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func startautodisc(what string, doit func() Interface) Interface {
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// TODO: monitor network configuration and rerun doit when it changes.
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done := make(chan Interface)
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ad := &autodisc{what: what, done: done}
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go func() { done <- doit(); close(done) }()
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return ad
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}
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func (n *autodisc) AddMapping(protocol string, extport, intport int, name string, lifetime time.Duration) error {
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if err := n.wait(); err != nil {
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return err
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}
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return n.found.AddMapping(protocol, extport, intport, name, lifetime)
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}
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func (n *autodisc) DeleteMapping(protocol string, extport, intport int) error {
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if err := n.wait(); err != nil {
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return err
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}
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return n.found.DeleteMapping(protocol, extport, intport)
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}
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func (n *autodisc) ExternalIP() (net.IP, error) {
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if err := n.wait(); err != nil {
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return nil, err
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}
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return n.found.ExternalIP()
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}
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func (n *autodisc) String() string {
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n.mu.Lock()
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defer n.mu.Unlock()
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if n.found == nil {
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return n.what
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} else {
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return n.found.String()
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}
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}
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func (n *autodisc) wait() error {
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n.mu.Lock()
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found := n.found
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n.mu.Unlock()
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if found != nil {
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// already discovered
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return nil
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}
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if found = <-n.done; found == nil {
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return errors.New("no devices discovered")
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}
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n.mu.Lock()
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n.found = found
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n.mu.Unlock()
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return nil
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}
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@ -0,0 +1,115 @@
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package nat
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import (
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"fmt"
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"net"
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"strings"
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"time"
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"github.com/jackpal/go-nat-pmp"
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)
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// natPMPClient adapts the NAT-PMP protocol implementation so it conforms to
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// the common interface.
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type pmp struct {
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gw net.IP
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c *natpmp.Client
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}
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func (n *pmp) String() string {
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return fmt.Sprintf("NAT-PMP(%v)", n.gw)
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}
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func (n *pmp) ExternalIP() (net.IP, error) {
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response, err := n.c.GetExternalAddress()
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if err != nil {
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return nil, err
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}
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return response.ExternalIPAddress[:], nil
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}
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func (n *pmp) AddMapping(protocol string, extport, intport int, name string, lifetime time.Duration) error {
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if lifetime <= 0 {
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return fmt.Errorf("lifetime must not be <= 0")
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}
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// Note order of port arguments is switched between our
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// AddMapping and the client's AddPortMapping.
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_, err := n.c.AddPortMapping(strings.ToLower(protocol), intport, extport, int(lifetime/time.Second))
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return err
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}
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func (n *pmp) DeleteMapping(protocol string, extport, intport int) (err error) {
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// To destroy a mapping, send an add-port with an internalPort of
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// the internal port to destroy, an external port of zero and a
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// time of zero.
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_, err = n.c.AddPortMapping(strings.ToLower(protocol), intport, 0, 0)
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return err
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}
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func discoverPMP() Interface {
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// run external address lookups on all potential gateways
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gws := potentialGateways()
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found := make(chan *pmp, len(gws))
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for i := range gws {
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gw := gws[i]
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go func() {
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c := natpmp.NewClient(gw)
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if _, err := c.GetExternalAddress(); err != nil {
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found <- nil
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} else {
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found <- &pmp{gw, c}
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}
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}()
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}
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// return the one that responds first.
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// discovery needs to be quick, so we stop caring about
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// any responses after a very short timeout.
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timeout := time.NewTimer(1 * time.Second)
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defer timeout.Stop()
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for _ = range gws {
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select {
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case c := <-found:
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if c != nil {
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return c
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}
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case <-timeout.C:
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return nil
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}
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}
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return nil
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}
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var (
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// LAN IP ranges
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_, lan10, _ = net.ParseCIDR("10.0.0.0/8")
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_, lan176, _ = net.ParseCIDR("172.16.0.0/12")
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_, lan192, _ = net.ParseCIDR("192.168.0.0/16")
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)
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// TODO: improve this. We currently assume that (on most networks)
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// the router is X.X.X.1 in a local LAN range.
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func potentialGateways() (gws []net.IP) {
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ifaces, err := net.Interfaces()
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if err != nil {
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return nil
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}
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for _, iface := range ifaces {
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ifaddrs, err := iface.Addrs()
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if err != nil {
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return gws
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}
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for _, addr := range ifaddrs {
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switch x := addr.(type) {
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case *net.IPNet:
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if lan10.Contains(x.IP) || lan176.Contains(x.IP) || lan192.Contains(x.IP) {
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ip := x.IP.Mask(x.Mask).To4()
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if ip != nil {
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ip[3] = ip[3] | 0x01
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gws = append(gws, ip)
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}
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}
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}
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}
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}
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return gws
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}
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@ -0,0 +1,149 @@
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package nat
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import (
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"errors"
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"fmt"
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"net"
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"strings"
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"time"
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"github.com/fjl/goupnp"
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"github.com/fjl/goupnp/dcps/internetgateway1"
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"github.com/fjl/goupnp/dcps/internetgateway2"
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)
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type upnp struct {
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dev *goupnp.RootDevice
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service string
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client upnpClient
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}
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type upnpClient interface {
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GetExternalIPAddress() (string, error)
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AddPortMapping(string, uint16, string, uint16, string, bool, string, uint32) error
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DeletePortMapping(string, uint16, string) error
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GetNATRSIPStatus() (sip bool, nat bool, err error)
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}
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func (n *upnp) ExternalIP() (addr net.IP, err error) {
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ipString, err := n.client.GetExternalIPAddress()
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if err != nil {
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return nil, err
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}
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ip := net.ParseIP(ipString)
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if ip == nil {
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return nil, errors.New("bad IP in response")
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}
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return ip, nil
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}
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func (n *upnp) AddMapping(protocol string, extport, intport int, desc string, lifetime time.Duration) error {
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ip, err := n.internalAddress()
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if err != nil {
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return nil
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}
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protocol = strings.ToUpper(protocol)
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lifetimeS := uint32(lifetime / time.Second)
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return n.client.AddPortMapping("", uint16(extport), protocol, uint16(intport), ip.String(), true, desc, lifetimeS)
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}
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func (n *upnp) internalAddress() (net.IP, error) {
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devaddr, err := net.ResolveUDPAddr("udp4", n.dev.URLBase.Host)
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if err != nil {
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return nil, err
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}
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ifaces, err := net.Interfaces()
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if err != nil {
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return nil, err
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}
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for _, iface := range ifaces {
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addrs, err := iface.Addrs()
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if err != nil {
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return nil, err
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}
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for _, addr := range addrs {
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switch x := addr.(type) {
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case *net.IPNet:
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if x.Contains(devaddr.IP) {
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return x.IP, nil
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}
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}
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}
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}
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return nil, fmt.Errorf("could not find local address in same net as %v", devaddr)
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}
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func (n *upnp) DeleteMapping(protocol string, extport, intport int) error {
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return n.client.DeletePortMapping("", uint16(extport), strings.ToUpper(protocol))
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}
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func (n *upnp) String() string {
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return "UPNP " + n.service
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}
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// discoverUPnP searches for Internet Gateway Devices
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// and returns the first one it can find on the local network.
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func discoverUPnP() Interface {
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found := make(chan *upnp, 2)
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// IGDv1
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go discover(found, internetgateway1.URN_WANConnectionDevice_1, func(dev *goupnp.RootDevice, sc goupnp.ServiceClient) *upnp {
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switch sc.Service.ServiceType {
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case internetgateway1.URN_WANIPConnection_1:
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return &upnp{dev, "IGDv1-IP1", &internetgateway1.WANIPConnection1{sc}}
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case internetgateway1.URN_WANPPPConnection_1:
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return &upnp{dev, "IGDv1-PPP1", &internetgateway1.WANPPPConnection1{sc}}
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}
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return nil
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})
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// IGDv2
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go discover(found, internetgateway2.URN_WANConnectionDevice_2, func(dev *goupnp.RootDevice, sc goupnp.ServiceClient) *upnp {
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switch sc.Service.ServiceType {
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case internetgateway2.URN_WANIPConnection_1:
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return &upnp{dev, "IGDv2-IP1", &internetgateway2.WANIPConnection1{sc}}
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case internetgateway2.URN_WANIPConnection_2:
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return &upnp{dev, "IGDv2-IP2", &internetgateway2.WANIPConnection2{sc}}
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case internetgateway2.URN_WANPPPConnection_1:
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return &upnp{dev, "IGDv2-PPP1", &internetgateway2.WANPPPConnection1{sc}}
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}
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return nil
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})
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for i := 0; i < cap(found); i++ {
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if c := <-found; c != nil {
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return c
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}
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}
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return nil
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}
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func discover(out chan<- *upnp, target string, matcher func(*goupnp.RootDevice, goupnp.ServiceClient) *upnp) {
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devs, err := goupnp.DiscoverDevices(target)
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if err != nil {
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return
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}
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found := false
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for i := 0; i < len(devs) && !found; i++ {
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if devs[i].Root == nil {
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continue
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}
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devs[i].Root.Device.VisitServices(func(service *goupnp.Service) {
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if found {
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return
|
||||
}
|
||||
// check for a matching IGD service
|
||||
sc := goupnp.ServiceClient{service.NewSOAPClient(), devs[i].Root, service}
|
||||
upnp := matcher(devs[i].Root, sc)
|
||||
if upnp == nil {
|
||||
return
|
||||
}
|
||||
// check whether port mapping is enabled
|
||||
if _, nat, err := upnp.client.GetNATRSIPStatus(); err != nil || !nat {
|
||||
return
|
||||
}
|
||||
out <- upnp
|
||||
found = true
|
||||
})
|
||||
}
|
||||
if !found {
|
||||
out <- nil
|
||||
}
|
||||
}
|
||||
Loading…
Reference in New Issue