syncthing/lib/upnp/upnp.go
greatroar 8065cf7e97
lib: Factor out getting IP address from net.Addr (#8538)
... and add fast paths for common cases.
2022-09-14 08:44:46 +02:00

494 lines
14 KiB
Go

// Copyright (C) 2014 The Syncthing Authors.
//
// Adapted from https://github.com/jackpal/Taipei-Torrent/blob/dd88a8bfac6431c01d959ce3c745e74b8a911793/IGD.go
// Copyright (c) 2010 Jack Palevich (https://github.com/jackpal/Taipei-Torrent/blob/dd88a8bfac6431c01d959ce3c745e74b8a911793/LICENSE)
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
// Package upnp implements UPnP InternetGatewayDevice discovery, querying, and port mapping.
package upnp
import (
"bufio"
"bytes"
"context"
"encoding/xml"
"errors"
"fmt"
"io"
"net"
"net/http"
"net/url"
"strings"
"sync"
"time"
"github.com/syncthing/syncthing/lib/build"
"github.com/syncthing/syncthing/lib/dialer"
"github.com/syncthing/syncthing/lib/nat"
"github.com/syncthing/syncthing/lib/osutil"
)
func init() {
nat.Register(Discover)
}
type upnpService struct {
ID string `xml:"serviceId"`
Type string `xml:"serviceType"`
ControlURL string `xml:"controlURL"`
}
type upnpDevice struct {
DeviceType string `xml:"deviceType"`
FriendlyName string `xml:"friendlyName"`
Devices []upnpDevice `xml:"deviceList>device"`
Services []upnpService `xml:"serviceList>service"`
}
type upnpRoot struct {
Device upnpDevice `xml:"device"`
}
// UnsupportedDeviceTypeError for unsupported UPnP device types (i.e upnp:rootdevice)
type UnsupportedDeviceTypeError struct {
deviceType string
}
func (e *UnsupportedDeviceTypeError) Error() string {
return fmt.Sprintf("Unsupported UPnP device of type %s", e.deviceType)
}
// Discover discovers UPnP InternetGatewayDevices.
// The order in which the devices appear in the results list is not deterministic.
func Discover(ctx context.Context, _, timeout time.Duration) []nat.Device {
var results []nat.Device
interfaces, err := net.Interfaces()
if err != nil {
l.Infoln("Listing network interfaces:", err)
return results
}
resultChan := make(chan nat.Device)
wg := &sync.WaitGroup{}
for _, intf := range interfaces {
// Interface flags seem to always be 0 on Windows
if !build.IsWindows && (intf.Flags&net.FlagUp == 0 || intf.Flags&net.FlagMulticast == 0) {
continue
}
for _, deviceType := range []string{"urn:schemas-upnp-org:device:InternetGatewayDevice:1", "urn:schemas-upnp-org:device:InternetGatewayDevice:2"} {
wg.Add(1)
go func(intf net.Interface, deviceType string) {
discover(ctx, &intf, deviceType, timeout, resultChan)
wg.Done()
}(intf, deviceType)
}
}
go func() {
wg.Wait()
close(resultChan)
}()
seenResults := make(map[string]bool)
for {
select {
case result, ok := <-resultChan:
if !ok {
return results
}
if seenResults[result.ID()] {
l.Debugf("Skipping duplicate result %s", result.ID())
continue
}
results = append(results, result)
seenResults[result.ID()] = true
l.Debugf("UPnP discovery result %s", result.ID())
case <-ctx.Done():
return nil
}
}
}
// Search for UPnP InternetGatewayDevices for <timeout> seconds.
// The order in which the devices appear in the result list is not deterministic
func discover(ctx context.Context, intf *net.Interface, deviceType string, timeout time.Duration, results chan<- nat.Device) {
ssdp := &net.UDPAddr{IP: []byte{239, 255, 255, 250}, Port: 1900}
tpl := `M-SEARCH * HTTP/1.1
HOST: 239.255.255.250:1900
ST: %s
MAN: "ssdp:discover"
MX: %d
USER-AGENT: syncthing/1.0
`
searchStr := fmt.Sprintf(tpl, deviceType, timeout/time.Second)
search := []byte(strings.ReplaceAll(searchStr, "\n", "\r\n") + "\r\n")
l.Debugln("Starting discovery of device type", deviceType, "on", intf.Name)
socket, err := net.ListenMulticastUDP("udp4", intf, &net.UDPAddr{IP: ssdp.IP})
if err != nil {
l.Debugln("UPnP discovery: listening to udp multicast:", err)
return
}
defer socket.Close() // Make sure our socket gets closed
l.Debugln("Sending search request for device type", deviceType, "on", intf.Name)
_, err = socket.WriteTo(search, ssdp)
if err != nil {
if e, ok := err.(net.Error); !ok || !e.Timeout() {
l.Debugln("UPnP discovery: sending search request:", err)
}
return
}
l.Debugln("Listening for UPnP response for device type", deviceType, "on", intf.Name)
ctx, cancel := context.WithTimeout(ctx, timeout)
defer cancel()
// Listen for responses until a timeout is reached or the context is
// cancelled
resp := make([]byte, 65536)
loop:
for {
if err := socket.SetDeadline(time.Now().Add(250 * time.Millisecond)); err != nil {
l.Infoln("UPnP socket:", err)
break
}
n, _, err := socket.ReadFrom(resp)
if err != nil {
select {
case <-ctx.Done():
break loop
default:
}
if e, ok := err.(net.Error); ok && e.Timeout() {
continue // continue reading
}
l.Infoln("UPnP read:", err) //legitimate error, not a timeout.
break
}
igds, err := parseResponse(ctx, deviceType, resp[:n])
if err != nil {
switch err.(type) {
case *UnsupportedDeviceTypeError:
l.Debugln(err.Error())
default:
if !errors.Is(err, context.Canceled) {
l.Infoln("UPnP parse:", err)
}
}
continue
}
for _, igd := range igds {
igd := igd // Copy before sending pointer to the channel.
select {
case results <- &igd:
case <-ctx.Done():
return
}
}
}
l.Debugln("Discovery for device type", deviceType, "on", intf.Name, "finished.")
}
func parseResponse(ctx context.Context, deviceType string, resp []byte) ([]IGDService, error) {
l.Debugln("Handling UPnP response:\n\n" + string(resp))
reader := bufio.NewReader(bytes.NewBuffer(resp))
request := &http.Request{}
response, err := http.ReadResponse(reader, request)
if err != nil {
return nil, err
}
respondingDeviceType := response.Header.Get("St")
if respondingDeviceType != deviceType {
return nil, &UnsupportedDeviceTypeError{deviceType: respondingDeviceType}
}
deviceDescriptionLocation := response.Header.Get("Location")
if deviceDescriptionLocation == "" {
return nil, errors.New("invalid IGD response: no location specified")
}
deviceDescriptionURL, err := url.Parse(deviceDescriptionLocation)
if err != nil {
l.Infoln("Invalid IGD location: " + err.Error())
}
deviceUSN := response.Header.Get("USN")
if deviceUSN == "" {
return nil, errors.New("invalid IGD response: USN not specified")
}
deviceUUID := strings.TrimPrefix(strings.Split(deviceUSN, "::")[0], "uuid:")
response, err = http.Get(deviceDescriptionLocation)
if err != nil {
return nil, err
}
defer response.Body.Close()
if response.StatusCode >= 400 {
return nil, errors.New("bad status code:" + response.Status)
}
var upnpRoot upnpRoot
err = xml.NewDecoder(response.Body).Decode(&upnpRoot)
if err != nil {
return nil, err
}
// Figure out our IP number, on the network used to reach the IGD.
// We do this in a fairly roundabout way by connecting to the IGD and
// checking the address of the local end of the socket. I'm open to
// suggestions on a better way to do this...
localIPAddress, err := localIP(ctx, deviceDescriptionURL)
if err != nil {
return nil, err
}
services, err := getServiceDescriptions(deviceUUID, localIPAddress, deviceDescriptionLocation, upnpRoot.Device)
if err != nil {
return nil, err
}
return services, nil
}
func localIP(ctx context.Context, url *url.URL) (net.IP, error) {
timeoutCtx, cancel := context.WithTimeout(ctx, time.Second)
defer cancel()
conn, err := dialer.DialContext(timeoutCtx, "tcp", url.Host)
if err != nil {
return nil, err
}
defer conn.Close()
return osutil.IPFromAddr(conn.LocalAddr())
}
func getChildDevices(d upnpDevice, deviceType string) []upnpDevice {
var result []upnpDevice
for _, dev := range d.Devices {
if dev.DeviceType == deviceType {
result = append(result, dev)
}
}
return result
}
func getChildServices(d upnpDevice, serviceType string) []upnpService {
var result []upnpService
for _, service := range d.Services {
if service.Type == serviceType {
result = append(result, service)
}
}
return result
}
func getServiceDescriptions(deviceUUID string, localIPAddress net.IP, rootURL string, device upnpDevice) ([]IGDService, error) {
var result []IGDService
if device.DeviceType == "urn:schemas-upnp-org:device:InternetGatewayDevice:1" {
descriptions := getIGDServices(deviceUUID, localIPAddress, rootURL, device,
"urn:schemas-upnp-org:device:WANDevice:1",
"urn:schemas-upnp-org:device:WANConnectionDevice:1",
[]string{"urn:schemas-upnp-org:service:WANIPConnection:1", "urn:schemas-upnp-org:service:WANPPPConnection:1"})
result = append(result, descriptions...)
} else if device.DeviceType == "urn:schemas-upnp-org:device:InternetGatewayDevice:2" {
descriptions := getIGDServices(deviceUUID, localIPAddress, rootURL, device,
"urn:schemas-upnp-org:device:WANDevice:2",
"urn:schemas-upnp-org:device:WANConnectionDevice:2",
[]string{"urn:schemas-upnp-org:service:WANIPConnection:2", "urn:schemas-upnp-org:service:WANPPPConnection:2"})
result = append(result, descriptions...)
} else {
return result, errors.New("[" + rootURL + "] Malformed root device description: not an InternetGatewayDevice.")
}
if len(result) < 1 {
return result, errors.New("[" + rootURL + "] Malformed device description: no compatible service descriptions found.")
}
return result, nil
}
func getIGDServices(deviceUUID string, localIPAddress net.IP, rootURL string, device upnpDevice, wanDeviceURN string, wanConnectionURN string, URNs []string) []IGDService {
var result []IGDService
devices := getChildDevices(device, wanDeviceURN)
if len(devices) < 1 {
l.Infoln(rootURL, "- malformed InternetGatewayDevice description: no WANDevices specified.")
return result
}
for _, device := range devices {
connections := getChildDevices(device, wanConnectionURN)
if len(connections) < 1 {
l.Infoln(rootURL, "- malformed ", wanDeviceURN, "description: no WANConnectionDevices specified.")
}
for _, connection := range connections {
for _, URN := range URNs {
services := getChildServices(connection, URN)
l.Debugln(rootURL, "- no services of type", URN, " found on connection.")
for _, service := range services {
if service.ControlURL == "" {
l.Infoln(rootURL+"- malformed", service.Type, "description: no control URL.")
} else {
u, _ := url.Parse(rootURL)
replaceRawPath(u, service.ControlURL)
l.Debugln(rootURL, "- found", service.Type, "with URL", u)
service := IGDService{
UUID: deviceUUID,
Device: device,
ServiceID: service.ID,
URL: u.String(),
URN: service.Type,
LocalIP: localIPAddress,
}
result = append(result, service)
}
}
}
}
}
return result
}
func replaceRawPath(u *url.URL, rp string) {
asURL, err := url.Parse(rp)
if err != nil {
return
} else if asURL.IsAbs() {
u.Path = asURL.Path
u.RawQuery = asURL.RawQuery
} else {
var p, q string
fs := strings.Split(rp, "?")
p = fs[0]
if len(fs) > 1 {
q = fs[1]
}
if p[0] == '/' {
u.Path = p
} else {
u.Path += p
}
u.RawQuery = q
}
}
func soapRequest(ctx context.Context, url, service, function, message string) ([]byte, error) {
tpl := `<?xml version="1.0" ?>
<s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/" s:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/">
<s:Body>%s</s:Body>
</s:Envelope>
`
var resp []byte
body := fmt.Sprintf(tpl, message)
req, err := http.NewRequestWithContext(ctx, "POST", url, strings.NewReader(body))
if err != nil {
return resp, err
}
req.Close = true
req.Header.Set("Content-Type", `text/xml; charset="utf-8"`)
req.Header.Set("User-Agent", "syncthing/1.0")
req.Header["SOAPAction"] = []string{fmt.Sprintf(`"%s#%s"`, service, function)} // Enforce capitalization in header-entry for sensitive routers. See issue #1696
req.Header.Set("Connection", "Close")
req.Header.Set("Cache-Control", "no-cache")
req.Header.Set("Pragma", "no-cache")
l.Debugln("SOAP Request URL: " + url)
l.Debugln("SOAP Action: " + req.Header.Get("SOAPAction"))
l.Debugln("SOAP Request:\n\n" + body)
r, err := http.DefaultClient.Do(req)
if err != nil {
l.Debugln("SOAP do:", err)
return resp, err
}
resp, _ = io.ReadAll(r.Body)
l.Debugf("SOAP Response: %s\n\n%s\n\n", r.Status, resp)
r.Body.Close()
if r.StatusCode >= 400 {
return resp, errors.New(function + ": " + r.Status)
}
return resp, nil
}
type soapGetExternalIPAddressResponseEnvelope struct {
XMLName xml.Name
Body soapGetExternalIPAddressResponseBody `xml:"Body"`
}
type soapGetExternalIPAddressResponseBody struct {
XMLName xml.Name
GetExternalIPAddressResponse getExternalIPAddressResponse `xml:"GetExternalIPAddressResponse"`
}
type getExternalIPAddressResponse struct {
NewExternalIPAddress string `xml:"NewExternalIPAddress"`
}
type soapErrorResponse struct {
ErrorCode int `xml:"Body>Fault>detail>UPnPError>errorCode"`
ErrorDescription string `xml:"Body>Fault>detail>UPnPError>errorDescription"`
}