131 lines
3.4 KiB
Go
131 lines
3.4 KiB
Go
// Copyright 2015 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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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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if x, ok := addr.(*net.IPNet); ok {
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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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