syncthing/lib/upnp/service.go

133 lines
3.3 KiB
Go

// Copyright (C) 2015 The Syncthing Authors.
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this file,
// You can obtain one at http://mozilla.org/MPL/2.0/.
package upnp
import (
"fmt"
"time"
"github.com/syncthing/syncthing/lib/config"
"github.com/syncthing/syncthing/lib/events"
"github.com/syncthing/syncthing/lib/sync"
"github.com/syncthing/syncthing/lib/util"
)
// Service runs a loop for discovery of IGDs (Internet Gateway Devices) and
// setup/renewal of a port mapping.
type Service struct {
cfg *config.Wrapper
localPort int
extPort int
extPortMut sync.Mutex
stop chan struct{}
}
func NewUPnPService(cfg *config.Wrapper, localPort int) *Service {
return &Service{
cfg: cfg,
localPort: localPort,
extPortMut: sync.NewMutex(),
}
}
func (s *Service) Serve() {
foundIGD := true
s.stop = make(chan struct{})
for {
igds := Discover(time.Duration(s.cfg.Options().UPnPTimeoutS) * time.Second)
if len(igds) > 0 {
foundIGD = true
s.extPortMut.Lock()
oldExtPort := s.extPort
s.extPortMut.Unlock()
newExtPort := s.tryIGDs(igds, oldExtPort)
s.extPortMut.Lock()
s.extPort = newExtPort
s.extPortMut.Unlock()
} else if foundIGD {
// Only print a notice if we've previously found an IGD or this is
// the first time around.
foundIGD = false
l.Infof("No UPnP device detected")
}
d := time.Duration(s.cfg.Options().UPnPRenewalM) * time.Minute
if d == 0 {
// We always want to do renewal so lets just pick a nice sane number.
d = 30 * time.Minute
}
select {
case <-s.stop:
return
case <-time.After(d):
}
}
}
func (s *Service) Stop() {
close(s.stop)
}
func (s *Service) ExternalPort() int {
s.extPortMut.Lock()
port := s.extPort
s.extPortMut.Unlock()
return port
}
func (s *Service) tryIGDs(igds []IGD, prevExtPort int) int {
// Lets try all the IGDs we found and use the first one that works.
// TODO: Use all of them, and sort out the resulting mess to the
// discovery announcement code...
for _, igd := range igds {
extPort, err := s.tryIGD(igd, prevExtPort)
if err != nil {
l.Warnf("Failed to set UPnP port mapping: external port %d on device %s.", extPort, igd.FriendlyIdentifier())
continue
}
if extPort != prevExtPort {
l.Infof("New UPnP port mapping: external port %d to local port %d.", extPort, s.localPort)
events.Default.Log(events.ExternalPortMappingChanged, map[string]int{"port": extPort})
}
l.Debugf("Created/updated UPnP port mapping for external port %d on device %s.", extPort, igd.FriendlyIdentifier())
return extPort
}
return 0
}
func (s *Service) tryIGD(igd IGD, suggestedPort int) (int, error) {
var err error
leaseTime := s.cfg.Options().UPnPLeaseM * 60
if suggestedPort != 0 {
// First try renewing our existing mapping.
name := fmt.Sprintf("syncthing-%d", suggestedPort)
err = igd.AddPortMapping(TCP, suggestedPort, s.localPort, name, leaseTime)
if err == nil {
return suggestedPort, nil
}
}
for i := 0; i < 10; i++ {
// Then try up to ten random ports.
extPort := 1024 + util.PredictableRandom.Intn(65535-1024)
name := fmt.Sprintf("syncthing-%d", extPort)
err = igd.AddPortMapping(TCP, extPort, s.localPort, name, leaseTime)
if err == nil {
return extPort, nil
}
}
return 0, err
}