From 1543833ca0b920d38e98994367f3871867d66781 Mon Sep 17 00:00:00 2001 From: Felix Lange Date: Tue, 10 Feb 2015 23:49:45 +0100 Subject: [PATCH] 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. --- p2p/nat/nat.go | 235 +++++++++++++++++++++++++++++++++++++++++++++ p2p/nat/natpmp.go | 115 ++++++++++++++++++++++ p2p/nat/natupnp.go | 149 ++++++++++++++++++++++++++++ 3 files changed, 499 insertions(+) create mode 100644 p2p/nat/nat.go create mode 100644 p2p/nat/natpmp.go create mode 100644 p2p/nat/natupnp.go diff --git a/p2p/nat/nat.go b/p2p/nat/nat.go new file mode 100644 index 0000000000..12d355ba18 --- /dev/null +++ b/p2p/nat/nat.go @@ -0,0 +1,235 @@ +// Package nat provides access to common port mapping protocols. +package nat + +import ( + "errors" + "fmt" + "net" + "strings" + "sync" + "time" + + "github.com/ethereum/go-ethereum/logger" + "github.com/jackpal/go-nat-pmp" +) + +var log = logger.NewLogger("P2P NAT") + +// An implementation of nat.Interface can map local ports to ports +// accessible from the Internet. +type Interface interface { + // These methods manage a mapping between a port on the local + // machine to a port that can be connected to from the internet. + // + // protocol is "UDP" or "TCP". Some implementations allow setting + // a display name for the mapping. The mapping may be removed by + // the gateway when its lifetime ends. + AddMapping(protocol string, extport, intport int, name string, lifetime time.Duration) error + DeleteMapping(protocol string, extport, intport int) error + + // This method should return the external (Internet-facing) + // address of the gateway device. + ExternalIP() (net.IP, error) + + // Should return name of the method. This is used for logging. + String() string +} + +// Parse parses a NAT interface description. +// The following formats are currently accepted. +// Note that mechanism names are not case-sensitive. +// +// "" or "none" return nil +// "extip:77.12.33.4" will assume the local machine is reachable on the given IP +// "any" uses the first auto-detected mechanism +// "upnp" uses the Universal Plug and Play protocol +// "pmp" uses NAT-PMP with an auto-detected gateway address +// "pmp:192.168.0.1" uses NAT-PMP with the given gateway address +func Parse(spec string) (Interface, error) { + var ( + parts = strings.SplitN(spec, ":", 2) + mech = strings.ToLower(parts[0]) + ip net.IP + ) + if len(parts) > 1 { + ip = net.ParseIP(parts[1]) + if ip == nil { + return nil, errors.New("invalid IP address") + } + } + switch mech { + case "", "none", "off": + return nil, nil + case "any", "auto", "on": + return Any(), nil + case "extip", "ip": + if ip == nil { + return nil, errors.New("missing IP address") + } + return ExtIP(ip), nil + case "upnp": + return UPnP(), nil + case "pmp", "natpmp", "nat-pmp": + return PMP(ip), nil + default: + return nil, fmt.Errorf("unknown mechanism %q", parts[0]) + } +} + +const ( + mapTimeout = 20 * time.Minute + mapUpdateInterval = 15 * time.Minute +) + +// Map adds a port mapping on m and keeps it alive until c is closed. +// This function is typically invoked in its own goroutine. +func Map(m Interface, c chan struct{}, protocol string, extport, intport int, name string) { + refresh := time.NewTimer(mapUpdateInterval) + defer func() { + refresh.Stop() + log.Debugf("Deleting port mapping: %s %d -> %d (%s) using %s\n", protocol, extport, intport, name, m) + m.DeleteMapping(protocol, extport, intport) + }() + log.Debugf("add mapping: %s %d -> %d (%s) using %s\n", protocol, extport, intport, name, m) + if err := m.AddMapping(protocol, intport, extport, name, mapTimeout); err != nil { + log.Errorf("mapping error: %v\n", err) + } + for { + select { + case _, ok := <-c: + if !ok { + return + } + case <-refresh.C: + log.DebugDetailf("refresh mapping: %s %d -> %d (%s) using %s\n", protocol, extport, intport, name, m) + if err := m.AddMapping(protocol, intport, extport, name, mapTimeout); err != nil { + log.Errorf("mapping error: %v\n", err) + } + refresh.Reset(mapUpdateInterval) + } + } +} + +// ExtIP assumes that the local machine is reachable on the given +// external IP address, and that any required ports were mapped manually. +// Mapping operations will not return an error but won't actually do anything. +func ExtIP(ip net.IP) Interface { + if ip == nil { + panic("IP must not be nil") + } + return extIP(ip) +} + +type extIP net.IP + +func (n extIP) ExternalIP() (net.IP, error) { return net.IP(n), nil } +func (n extIP) String() string { return fmt.Sprintf("ExtIP(%v)", net.IP(n)) } + +// These do nothing. +func (extIP) AddMapping(string, int, int, string, time.Duration) error { return nil } +func (extIP) DeleteMapping(string, int, int) error { return nil } + +// Any returns a port mapper that tries to discover any supported +// mechanism on the local network. +func Any() Interface { + // TODO: attempt to discover whether the local machine has an + // Internet-class address. Return ExtIP in this case. + return startautodisc("UPnP or NAT-PMP", func() Interface { + found := make(chan Interface, 2) + go func() { found <- discoverUPnP() }() + go func() { found <- discoverPMP() }() + for i := 0; i < cap(found); i++ { + if c := <-found; c != nil { + return c + } + } + return nil + }) +} + +// UPnP returns a port mapper that uses UPnP. It will attempt to +// discover the address of your router using UDP broadcasts. +func UPnP() Interface { + return startautodisc("UPnP", discoverUPnP) +} + +// PMP returns a port mapper that uses NAT-PMP. The provided gateway +// address should be the IP of your router. If the given gateway +// address is nil, PMP will attempt to auto-discover the router. +func PMP(gateway net.IP) Interface { + if gateway != nil { + return &pmp{gw: gateway, c: natpmp.NewClient(gateway)} + } + return startautodisc("NAT-PMP", discoverPMP) +} + +// autodisc represents a port mapping mechanism that is still being +// auto-discovered. Calls to the Interface methods on this type will +// wait until the discovery is done and then call the method on the +// discovered mechanism. +// +// This type is useful because discovery can take a while but we +// want return an Interface value from UPnP, PMP and Auto immediately. +type autodisc struct { + what string + done <-chan Interface + + mu sync.Mutex + found Interface +} + +func startautodisc(what string, doit func() Interface) Interface { + // TODO: monitor network configuration and rerun doit when it changes. + done := make(chan Interface) + ad := &autodisc{what: what, done: done} + go func() { done <- doit(); close(done) }() + return ad +} + +func (n *autodisc) AddMapping(protocol string, extport, intport int, name string, lifetime time.Duration) error { + if err := n.wait(); err != nil { + return err + } + return n.found.AddMapping(protocol, extport, intport, name, lifetime) +} + +func (n *autodisc) DeleteMapping(protocol string, extport, intport int) error { + if err := n.wait(); err != nil { + return err + } + return n.found.DeleteMapping(protocol, extport, intport) +} + +func (n *autodisc) ExternalIP() (net.IP, error) { + if err := n.wait(); err != nil { + return nil, err + } + return n.found.ExternalIP() +} + +func (n *autodisc) String() string { + n.mu.Lock() + defer n.mu.Unlock() + if n.found == nil { + return n.what + } else { + return n.found.String() + } +} + +func (n *autodisc) wait() error { + n.mu.Lock() + found := n.found + n.mu.Unlock() + if found != nil { + // already discovered + return nil + } + if found = <-n.done; found == nil { + return errors.New("no devices discovered") + } + n.mu.Lock() + n.found = found + n.mu.Unlock() + return nil +} diff --git a/p2p/nat/natpmp.go b/p2p/nat/natpmp.go new file mode 100644 index 0000000000..f249c60732 --- /dev/null +++ b/p2p/nat/natpmp.go @@ -0,0 +1,115 @@ +package nat + +import ( + "fmt" + "net" + "strings" + "time" + + "github.com/jackpal/go-nat-pmp" +) + +// natPMPClient adapts the NAT-PMP protocol implementation so it conforms to +// the common interface. +type pmp struct { + gw net.IP + c *natpmp.Client +} + +func (n *pmp) String() string { + return fmt.Sprintf("NAT-PMP(%v)", n.gw) +} + +func (n *pmp) ExternalIP() (net.IP, error) { + response, err := n.c.GetExternalAddress() + if err != nil { + return nil, err + } + return response.ExternalIPAddress[:], nil +} + +func (n *pmp) AddMapping(protocol string, extport, intport int, name string, lifetime time.Duration) error { + if lifetime <= 0 { + return fmt.Errorf("lifetime must not be <= 0") + } + // Note order of port arguments is switched between our + // AddMapping and the client's AddPortMapping. + _, err := n.c.AddPortMapping(strings.ToLower(protocol), intport, extport, int(lifetime/time.Second)) + return err +} + +func (n *pmp) DeleteMapping(protocol string, extport, intport 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.c.AddPortMapping(strings.ToLower(protocol), intport, 0, 0) + return err +} + +func discoverPMP() Interface { + // run external address lookups on all potential gateways + gws := potentialGateways() + found := make(chan *pmp, len(gws)) + for i := range gws { + gw := gws[i] + go func() { + c := natpmp.NewClient(gw) + if _, err := c.GetExternalAddress(); err != nil { + found <- nil + } else { + found <- &pmp{gw, c} + } + }() + } + // return the one that responds first. + // discovery needs to be quick, so we stop caring about + // any responses after a very short timeout. + timeout := time.NewTimer(1 * time.Second) + defer timeout.Stop() + for _ = range gws { + select { + case c := <-found: + if c != nil { + return c + } + case <-timeout.C: + return nil + } + } + return nil +} + +var ( + // LAN IP ranges + _, lan10, _ = net.ParseCIDR("10.0.0.0/8") + _, lan176, _ = net.ParseCIDR("172.16.0.0/12") + _, lan192, _ = net.ParseCIDR("192.168.0.0/16") +) + +// TODO: improve this. We currently assume that (on most networks) +// the router is X.X.X.1 in a local LAN range. +func potentialGateways() (gws []net.IP) { + ifaces, err := net.Interfaces() + if err != nil { + return nil + } + for _, iface := range ifaces { + ifaddrs, err := iface.Addrs() + if err != nil { + return gws + } + for _, addr := range ifaddrs { + switch x := addr.(type) { + case *net.IPNet: + if lan10.Contains(x.IP) || lan176.Contains(x.IP) || lan192.Contains(x.IP) { + ip := x.IP.Mask(x.Mask).To4() + if ip != nil { + ip[3] = ip[3] | 0x01 + gws = append(gws, ip) + } + } + } + } + } + return gws +} diff --git a/p2p/nat/natupnp.go b/p2p/nat/natupnp.go new file mode 100644 index 0000000000..25cbc0d711 --- /dev/null +++ b/p2p/nat/natupnp.go @@ -0,0 +1,149 @@ +package nat + +import ( + "errors" + "fmt" + "net" + "strings" + "time" + + "github.com/fjl/goupnp" + "github.com/fjl/goupnp/dcps/internetgateway1" + "github.com/fjl/goupnp/dcps/internetgateway2" +) + +type upnp struct { + dev *goupnp.RootDevice + service string + client upnpClient +} + +type upnpClient interface { + GetExternalIPAddress() (string, error) + AddPortMapping(string, uint16, string, uint16, string, bool, string, uint32) error + DeletePortMapping(string, uint16, string) error + GetNATRSIPStatus() (sip bool, nat bool, err error) +} + +func (n *upnp) ExternalIP() (addr net.IP, err error) { + ipString, err := n.client.GetExternalIPAddress() + if err != nil { + return nil, err + } + ip := net.ParseIP(ipString) + if ip == nil { + return nil, errors.New("bad IP in response") + } + return ip, nil +} + +func (n *upnp) AddMapping(protocol string, extport, intport int, desc string, lifetime time.Duration) error { + ip, err := n.internalAddress() + if err != nil { + return nil + } + protocol = strings.ToUpper(protocol) + lifetimeS := uint32(lifetime / time.Second) + return n.client.AddPortMapping("", uint16(extport), protocol, uint16(intport), ip.String(), true, desc, lifetimeS) +} + +func (n *upnp) internalAddress() (net.IP, error) { + devaddr, err := net.ResolveUDPAddr("udp4", n.dev.URLBase.Host) + if err != nil { + return nil, err + } + ifaces, err := net.Interfaces() + if err != nil { + return nil, err + } + for _, iface := range ifaces { + addrs, err := iface.Addrs() + if err != nil { + return nil, err + } + for _, addr := range addrs { + switch x := addr.(type) { + case *net.IPNet: + if x.Contains(devaddr.IP) { + return x.IP, nil + } + } + } + } + return nil, fmt.Errorf("could not find local address in same net as %v", devaddr) +} + +func (n *upnp) DeleteMapping(protocol string, extport, intport int) error { + return n.client.DeletePortMapping("", uint16(extport), strings.ToUpper(protocol)) +} + +func (n *upnp) String() string { + return "UPNP " + n.service +} + +// discoverUPnP searches for Internet Gateway Devices +// and returns the first one it can find on the local network. +func discoverUPnP() Interface { + found := make(chan *upnp, 2) + // IGDv1 + go discover(found, internetgateway1.URN_WANConnectionDevice_1, func(dev *goupnp.RootDevice, sc goupnp.ServiceClient) *upnp { + switch sc.Service.ServiceType { + case internetgateway1.URN_WANIPConnection_1: + return &upnp{dev, "IGDv1-IP1", &internetgateway1.WANIPConnection1{sc}} + case internetgateway1.URN_WANPPPConnection_1: + return &upnp{dev, "IGDv1-PPP1", &internetgateway1.WANPPPConnection1{sc}} + } + return nil + }) + // IGDv2 + go discover(found, internetgateway2.URN_WANConnectionDevice_2, func(dev *goupnp.RootDevice, sc goupnp.ServiceClient) *upnp { + switch sc.Service.ServiceType { + case internetgateway2.URN_WANIPConnection_1: + return &upnp{dev, "IGDv2-IP1", &internetgateway2.WANIPConnection1{sc}} + case internetgateway2.URN_WANIPConnection_2: + return &upnp{dev, "IGDv2-IP2", &internetgateway2.WANIPConnection2{sc}} + case internetgateway2.URN_WANPPPConnection_1: + return &upnp{dev, "IGDv2-PPP1", &internetgateway2.WANPPPConnection1{sc}} + } + return nil + }) + for i := 0; i < cap(found); i++ { + if c := <-found; c != nil { + return c + } + } + return nil +} + +func discover(out chan<- *upnp, target string, matcher func(*goupnp.RootDevice, goupnp.ServiceClient) *upnp) { + devs, err := goupnp.DiscoverDevices(target) + if err != nil { + return + } + found := false + for i := 0; i < len(devs) && !found; i++ { + if devs[i].Root == nil { + continue + } + devs[i].Root.Device.VisitServices(func(service *goupnp.Service) { + if found { + 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 + } +}