Update dependencies

2024-11-01 17:33:34 +00:00
parent 033ac0b400
commit 5cdfab398d
3596 changed files with 1033483 additions and 259 deletions
--- a/vendor/github.com/tailscale/goupnp/.gitignore
+++ b/vendor/github.com/tailscale/goupnp/.gitignore
@@ -0,0 +1,2 @@
+*.zip
+*.sublime-workspace
--- a/vendor/github.com/tailscale/goupnp/GUIDE.md
+++ b/vendor/github.com/tailscale/goupnp/GUIDE.md
@@ -0,0 +1,133 @@
+# Guide
+
+This is a quick guide with example code for common use cases that might be
+helpful for people wanting a quick guide to common ways that people would
+want to use this library.
+
+## Internet Gateways
+
+`goupnp/dcps/internetgateway1` and `goupnp/dcps/internetgateway2` implement
+different version standards that allow clients to interact with devices like
+home consumer routers, but you can probably get by with just
+`internetgateway2`. Some very common use cases to talk to such devices are:
+
+- Requesting the external Internet-facing IP address.
+- Requesting a port be forwarded from the external (Internet-facing) interface
+  to a port on the LAN.
+
+Different routers implement different standards, so you may have to request
+multiple clients to find the one that your router needs. The most useful ones
+for the purpose above can be requested with the following functions:
+
+- `internetgateway2.NewWANIPConnection1Clients()`
+- `internetgateway2.NewWANIPConnection2Clients()`
+- `internetgateway2.NewWANPPPConnection1Clients()`
+
+Fortunately, each of the clients returned by these functions provide the same
+method signatures for the purposes listed above. So you could request multiple
+clients, and whichever one you find, and return it from a function in a variable
+of the common interface, e.g:
+
+```go
+type RouterClient interface {
+	AddPortMapping(
+		NewRemoteHost string,
+		NewExternalPort uint16,
+		NewProtocol string,
+		NewInternalPort uint16,
+		NewInternalClient string,
+		NewEnabled bool,
+		NewPortMappingDescription string,
+		NewLeaseDuration uint32,
+	) (err error)
+
+	GetExternalIPAddress() (
+		NewExternalIPAddress string,
+		err error,
+	)
+}
+
+func PickRouterClient(ctx context.Context) (RouterClient, error) {
+	tasks, _ := errgroup.WithContext(ctx)
+	// Request each type of client in parallel, and return what is found.
+	var ip1Clients []*internetgateway2.WANIPConnection1
+	tasks.Go(func() error {
+		var err error
+		ip1Clients, _, err = internetgateway2.NewWANIPConnection1Clients()
+		return err
+	})
+	var ip2Clients []*internetgateway2.WANIPConnection2
+	tasks.Go(func() error {
+		var err error
+		ip2Clients, _, err = internetgateway2.NewWANIPConnection2Clients()
+		return err
+	})
+	var ppp1Clients []*internetgateway2.WANPPPConnection1
+	tasks.Go(func() error {
+		var err error
+		ppp1Clients, _, err = internetgateway2.NewWANPPPConnection1Clients()
+		return err
+	})
+
+	if err := tasks.Wait(); err != nil {
+		return nil, err
+	}
+
+	// Trivial handling for where we find exactly one device to talk to, you
+	// might want to provide more flexible handling than this if multiple
+	// devices are found.
+	switch {
+	case len(ip2Clients) == 1:
+		return ip2Clients[0], nil
+	case len(ip1Clients) == 1:
+		return ip1Clients[0], nil
+	case len(ppp1Clients) == 1:
+		return ppp1Clients[0], nil
+	default:
+		return nil, errors.New("multiple or no services found")
+	}
+}
+```
+
+You could then use this function to create a client, and both request the
+external IP address and forward it to a port on your local network, e.g:
+
+```go
+func GetIPAndForwardPort(ctx context.Context) error {
+	client, err := PickRouterClient(ctx)
+	if err != nil {
+		return err
+	}
+
+	externalIP, err := client.GetExternalIPAddress()
+	if err != nil {
+		return err
+	}
+	fmt.Println("Our external IP address is: ", externalIP)
+
+	return client.AddPortMapping(
+		"",
+		// External port number to expose to Internet:
+		1234,
+		// Forward TCP (this could be "UDP" if we wanted that instead).
+		"TCP",
+		// Internal port number on the LAN to forward to.
+		// Some routers might not support this being different to the external
+		// port number.
+		1234,
+		// Internal address on the LAN we want to forward to.
+		"192.168.1.6",
+		// Enabled:
+		true,
+		// Informational description for the client requesting the port forwarding.
+		"MyProgramName",
+		// How long should the port forward last for in seconds.
+		// If you want to keep it open for longer and potentially across router
+		// resets, you might want to periodically request before this elapses.
+		3600,
+	)
+}
+```
+
+The code above is of course just a relatively trivial example that you can
+tailor to your own use case.
--- a/vendor/github.com/tailscale/goupnp/LICENSE
+++ b/vendor/github.com/tailscale/goupnp/LICENSE
@@ -0,0 +1,23 @@
+Copyright (c) 2013, John Beisley <johnbeisleyuk@gmail.com>
+All rights reserved.
+
+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.
+
+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 HOLDER 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.
--- a/vendor/github.com/tailscale/goupnp/README.md
+++ b/vendor/github.com/tailscale/goupnp/README.md
@@ -0,0 +1,68 @@
+# tailscale/goupnp
+
+This repo is a temporary fork of [huin/goupnp](https://github.com/huin/goupnp)(A UPnP client
+library for Go), customized for UPnP support in Tailscale.
+
+## Installation
+
+Run `go get -u github.com/tailscale/goupnp`.
+
+## Documentation
+
+See [GUIDE.md](GUIDE.md) for a quick start on the most common use case for this
+library.
+
+Supported DCPs (you probably want to start with one of these):
+
+- [![GoDoc](https://godoc.org/github.com/tailscale/goupnp?status.svg) av1](https://godoc.org/github.com/tailscale/goupnp/dcps/av1) - Client for UPnP Device Control Protocol MediaServer v1 and MediaRenderer v1.
+- [![GoDoc](https://godoc.org/github.com/tailscale/goupnp?status.svg) internetgateway1](https://godoc.org/github.com/tailscale/goupnp/dcps/internetgateway1) - Client for UPnP Device Control Protocol Internet Gateway Device v1.
+- [![GoDoc](https://godoc.org/github.com/tailscale/goupnp?status.svg) internetgateway2](https://godoc.org/github.com/tailscale/goupnp/dcps/internetgateway2) - Client for UPnP Device Control Protocol Internet Gateway Device v2.
+
+Core components:
+
+- [![GoDoc](https://godoc.org/github.com/tailscale/goupnp?status.svg) (goupnp)](https://godoc.org/github.com/tailscale/goupnp) core library - contains datastructures and utilities typically used by the implemented DCPs.
+- [![GoDoc](https://godoc.org/github.com/tailscale/goupnp?status.svg) httpu](https://godoc.org/github.com/tailscale/goupnp/httpu) HTTPU implementation, underlies SSDP.
+- [![GoDoc](https://godoc.org/github.com/tailscale/goupnp?status.svg) ssdp](https://godoc.org/github.com/tailscale/goupnp/ssdp) SSDP client implementation (simple service discovery protocol) - used to discover UPnP services on a network.
+- [![GoDoc](https://godoc.org/github.com/tailscale/goupnp?status.svg) soap](https://godoc.org/github.com/tailscale/goupnp/soap) SOAP client implementation (simple object access protocol) - used to communicate with discovered services.
+
+## Regenerating dcps generated source code:
+
+1. Build code generator:
+
+   `go get -u github.com/tailscale/goupnp/cmd/goupnpdcpgen`
+
+2. Regenerate the code:
+
+   `go generate ./...`
+
+## Supporting additional UPnP devices and services:
+
+Supporting additional services is, in the trivial case, simply a matter of
+adding the service to the `dcpMetadata` whitelist in `cmd/goupnpdcpgen/metadata.go`,
+regenerating the source code (see above), and committing that source code.
+
+However, it would be helpful if anyone needing such a service could test the
+service against the service they have, and then reporting any trouble
+encountered as an [issue on this
+project](https://github.com/tailscale/goupnp/issues/new). If it just works, then
+please report at least minimal working functionality as an issue, and
+optionally contribute the metadata upstream.
+
+## Migrating due to Breaking Changes
+
+- \#40 introduced a breaking change to handling non-utf8 encodings, but removes a heavy
+  dependency on `golang.org/x/net` with charset encodings. If this breaks your usage of this
+  library, you can return to the old behavior by modifying the exported variable and importing
+  the package yourself:
+
+```go
+import (
+  "golang.org/x/net/html/charset"
+  "github.com/tailscale/goupnp"
+)
+
+func init() {
+  // should be modified before goupnp libraries are in use.
+  goupnp.CharsetReaderFault = charset.NewReaderLabel
+}
+```
--- a/vendor/github.com/tailscale/goupnp/dcps/internetgateway2/gen.go
+++ b/vendor/github.com/tailscale/goupnp/dcps/internetgateway2/gen.go
@@ -0,0 +1,2 @@
+//go:generate goupnpdcpgen -dcp_name internetgateway2
+package internetgateway2
--- a/vendor/github.com/tailscale/goupnp/dcps/internetgateway2/internetgateway2.go
+++ b/vendor/github.com/tailscale/goupnp/dcps/internetgateway2/internetgateway2.go
--- a/vendor/github.com/tailscale/goupnp/device.go
+++ b/vendor/github.com/tailscale/goupnp/device.go
@@ -0,0 +1,192 @@
+// This file contains XML structures for communicating with UPnP devices.
+
+package goupnp
+
+import (
+	"context"
+	"encoding/xml"
+	"errors"
+	"fmt"
+	"net/http"
+	"net/url"
+
+	"github.com/tailscale/goupnp/scpd"
+	"github.com/tailscale/goupnp/soap"
+)
+
+const (
+	DeviceXMLNamespace = "urn:schemas-upnp-org:device-1-0"
+)
+
+// RootDevice is the device description as described by section 2.3 "Device
+// description" in
+// http://upnp.org/specs/arch/UPnP-arch-DeviceArchitecture-v1.1.pdf
+type RootDevice struct {
+	XMLName     xml.Name    `xml:"root"`
+	SpecVersion SpecVersion `xml:"specVersion"`
+	URLBase     url.URL     `xml:"-"`
+	URLBaseStr  string      `xml:"URLBase"`
+	Device      Device      `xml:"device"`
+}
+
+// SetURLBase sets the URLBase for the RootDevice and its underlying components.
+func (root *RootDevice) SetURLBase(urlBase *url.URL) {
+	root.URLBase = *urlBase
+	root.URLBaseStr = urlBase.String()
+	root.Device.SetURLBase(urlBase)
+}
+
+// SpecVersion is part of a RootDevice, describes the version of the
+// specification that the data adheres to.
+type SpecVersion struct {
+	Major int32 `xml:"major"`
+	Minor int32 `xml:"minor"`
+}
+
+// Device is a UPnP device. It can have child devices.
+type Device struct {
+	DeviceType       string    `xml:"deviceType"`
+	FriendlyName     string    `xml:"friendlyName"`
+	Manufacturer     string    `xml:"manufacturer"`
+	ManufacturerURL  URLField  `xml:"manufacturerURL"`
+	ModelDescription string    `xml:"modelDescription"`
+	ModelName        string    `xml:"modelName"`
+	ModelNumber      string    `xml:"modelNumber"`
+	ModelURL         URLField  `xml:"modelURL"`
+	SerialNumber     string    `xml:"serialNumber"`
+	UDN              string    `xml:"UDN"`
+	UPC              string    `xml:"UPC,omitempty"`
+	Icons            []Icon    `xml:"iconList>icon,omitempty"`
+	Services         []Service `xml:"serviceList>service,omitempty"`
+	Devices          []Device  `xml:"deviceList>device,omitempty"`
+
+	// Extra observed elements:
+	PresentationURL URLField `xml:"presentationURL"`
+}
+
+// VisitDevices calls visitor for the device, and all its descendent devices.
+func (device *Device) VisitDevices(visitor func(*Device)) {
+	visitor(device)
+	for i := range device.Devices {
+		device.Devices[i].VisitDevices(visitor)
+	}
+}
+
+// VisitServices calls visitor for all Services under the device and all its
+// descendent devices.
+func (device *Device) VisitServices(visitor func(*Service)) {
+	device.VisitDevices(func(d *Device) {
+		for i := range d.Services {
+			visitor(&d.Services[i])
+		}
+	})
+}
+
+// FindService finds all (if any) Services under the device and its descendents
+// that have the given ServiceType.
+func (device *Device) FindService(ctx context.Context, serviceType string) []*Service {
+	var services []*Service
+	device.VisitServices(func(s *Service) {
+		if s.ServiceType == serviceType {
+			services = append(services, s)
+		}
+	})
+	return services
+}
+
+// SetURLBase sets the URLBase for the Device and its underlying components.
+func (device *Device) SetURLBase(urlBase *url.URL) {
+	device.ManufacturerURL.SetURLBase(urlBase)
+	device.ModelURL.SetURLBase(urlBase)
+	device.PresentationURL.SetURLBase(urlBase)
+	for i := range device.Icons {
+		device.Icons[i].SetURLBase(urlBase)
+	}
+	for i := range device.Services {
+		device.Services[i].SetURLBase(urlBase)
+	}
+	for i := range device.Devices {
+		device.Devices[i].SetURLBase(urlBase)
+	}
+}
+
+func (device *Device) String() string {
+	return fmt.Sprintf("Device ID %s : %s (%s)", device.UDN, device.DeviceType, device.FriendlyName)
+}
+
+// Icon is a representative image that a device might include in its
+// description.
+type Icon struct {
+	Mimetype string   `xml:"mimetype"`
+	Width    int32    `xml:"width"`
+	Height   int32    `xml:"height"`
+	Depth    int32    `xml:"depth"`
+	URL      URLField `xml:"url"`
+}
+
+// SetURLBase sets the URLBase for the Icon.
+func (icon *Icon) SetURLBase(url *url.URL) {
+	icon.URL.SetURLBase(url)
+}
+
+// Service is a service provided by a UPnP Device.
+type Service struct {
+	ServiceType string   `xml:"serviceType"`
+	ServiceId   string   `xml:"serviceId"`
+	SCPDURL     URLField `xml:"SCPDURL"`
+	ControlURL  URLField `xml:"controlURL"`
+	EventSubURL URLField `xml:"eventSubURL"`
+}
+
+// SetURLBase sets the URLBase for the Service.
+func (srv *Service) SetURLBase(urlBase *url.URL) {
+	srv.SCPDURL.SetURLBase(urlBase)
+	srv.ControlURL.SetURLBase(urlBase)
+	srv.EventSubURL.SetURLBase(urlBase)
+}
+
+func (srv *Service) String() string {
+	return fmt.Sprintf("Service ID %s : %s", srv.ServiceId, srv.ServiceType)
+}
+
+// RequestSCPD requests the SCPD (soap actions and state variables description)
+// for the service.
+func (srv *Service) RequestSCPD(ctx context.Context) (*scpd.SCPD, error) {
+	if !srv.SCPDURL.Ok {
+		return nil, errors.New("bad/missing SCPD URL, or no URLBase has been set")
+	}
+	s := new(scpd.SCPD)
+	if err := requestXml(ctx, srv.SCPDURL.URL.String(), scpd.SCPDXMLNamespace, s); err != nil {
+		return nil, err
+	}
+	return s, nil
+}
+
+// NewSOAPClient returns a new SOAP client to the service's control
+// URL, using the provided http.Client.
+// If httpc is nil, http.DefaultClient is used.
+func (srv *Service) NewSOAPClient(httpc *http.Client) *soap.SOAPClient {
+	if httpc == nil {
+		httpc = http.DefaultClient
+	}
+	return soap.NewSOAPClient(srv.ControlURL.URL, httpc)
+}
+
+// URLField is a URL that is part of a device description.
+type URLField struct {
+	URL url.URL `xml:"-"`
+	Ok  bool    `xml:"-"`
+	Str string  `xml:",chardata"`
+}
+
+func (uf *URLField) SetURLBase(urlBase *url.URL) {
+	refUrl, err := url.Parse(uf.Str)
+	if err != nil {
+		uf.URL = url.URL{}
+		uf.Ok = false
+		return
+	}
+
+	uf.URL = *urlBase.ResolveReference(refUrl)
+	uf.Ok = true
+}
--- a/vendor/github.com/tailscale/goupnp/goupnp.go
+++ b/vendor/github.com/tailscale/goupnp/goupnp.go
@@ -0,0 +1,164 @@
+// goupnp is an implementation of a client for various UPnP services.
+//
+// For most uses, it is recommended to use the code-generated packages under
+// github.com/tailscale/goupnp/dcps. Example use is shown at
+// http://godoc.org/github.com/tailscale/goupnp/example
+//
+// A commonly used client is internetgateway1.WANPPPConnection1:
+// http://godoc.org/github.com/tailscale/goupnp/dcps/internetgateway1#WANPPPConnection1
+//
+// Currently only a couple of schemas have code generated for them from the
+// UPnP example XML specifications. Not all methods will work on these clients,
+// because the generated stubs contain the full set of specified methods from
+// the XML specifications, and the discovered services will likely support a
+// subset of those methods.
+package goupnp
+
+import (
+	"context"
+	"encoding/xml"
+	"fmt"
+	"io"
+	"net/http"
+	"net/url"
+
+	"github.com/tailscale/goupnp/ssdp"
+)
+
+// ContextError is an error that wraps an error with some context information.
+type ContextError struct {
+	Context string
+	Err     error
+}
+
+func ctxError(err error, msg string) ContextError {
+	return ContextError{Context: msg, Err: err}
+}
+
+func ctxErrorf(err error, msg string, args ...interface{}) ContextError {
+	return ContextError{
+		Context: fmt.Sprintf(msg, args...),
+		Err:     err,
+	}
+}
+
+func (err ContextError) Error() string {
+	return fmt.Sprintf("%s: %v", err.Context, err.Err)
+}
+
+// MaybeRootDevice contains either a RootDevice or an error.
+type MaybeRootDevice struct {
+	// Identifier of the device.
+	USN string
+
+	// Set iff Err == nil.
+	Root *RootDevice
+
+	// The location the device was discovered at. This can be used with
+	// DeviceByURL, assuming the device is still present. A location represents
+	// the discovery of a device, regardless of if there was an error probing it.
+	Location *url.URL
+
+	// Any error encountered probing a discovered device.
+	Err error
+}
+
+// DiscoverDevices attempts to find targets of the given type. This is
+// typically the entry-point for this package. searchTarget is typically a URN
+// in the form "urn:schemas-upnp-org:device:..." or
+// "urn:schemas-upnp-org:service:...". A single error is returned for errors
+// while attempting to send the query. An error or RootDevice is returned for
+// each discovered RootDevice.
+func DiscoverDevices(ctx context.Context, searchTarget string) ([]MaybeRootDevice, error) {
+	hc, err := httpuClient()
+	if err != nil {
+		return nil, err
+	}
+	defer hc.Close()
+	responses, err := ssdp.SSDPRawSearch(ctx, hc, string(searchTarget), 3)
+	if err != nil {
+		return nil, err
+	}
+
+	results := make([]MaybeRootDevice, len(responses))
+	for i, response := range responses {
+		maybe := &results[i]
+		maybe.USN = response.Header.Get("USN")
+		loc, err := response.Location()
+		if err != nil {
+			maybe.Err = ContextError{"unexpected bad location from search", err}
+			continue
+		}
+		maybe.Location = loc
+		if root, err := DeviceByURL(ctx, loc); err != nil {
+			maybe.Err = err
+		} else {
+			maybe.Root = root
+		}
+	}
+
+	return results, nil
+}
+
+func DeviceByURL(ctx context.Context, loc *url.URL) (*RootDevice, error) {
+	locStr := loc.String()
+	root := new(RootDevice)
+	if err := requestXml(ctx, locStr, DeviceXMLNamespace, root); err != nil {
+		return nil, ContextError{fmt.Sprintf("error requesting root device details from %q", locStr), err}
+	}
+	var urlBaseStr string
+	if root.URLBaseStr != "" {
+		urlBaseStr = root.URLBaseStr
+	} else {
+		urlBaseStr = locStr
+	}
+	urlBase, err := url.Parse(urlBaseStr)
+	if err != nil {
+		return nil, ContextError{fmt.Sprintf("error parsing location URL %q", locStr), err}
+	}
+	root.SetURLBase(urlBase)
+	return root, nil
+}
+
+// CharsetReaderDefault specifies the charset reader used while decoding the output
+// from a UPnP server. It can be modified in an init function to allow for non-utf8 encodings,
+// but should not be changed after requesting clients.
+var CharsetReaderDefault func(charset string, input io.Reader) (io.Reader, error)
+
+// contextKey is an unexported type which prevents construction of other contextKeys.
+type httpContextKey struct{}
+
+// WithHTTPClient returns a context wrapping ctx with the HTTP client set to c.
+// If c is nil, http.DefaultClient is used.
+func WithHTTPClient(ctx context.Context, c *http.Client) context.Context {
+	return context.WithValue(ctx, httpContextKey{}, c)
+}
+
+func httpClient(ctx context.Context) *http.Client {
+	if c, _ := ctx.Value(httpContextKey{}).(*http.Client); c != nil {
+		return c
+	}
+	return http.DefaultClient
+}
+
+func requestXml(ctx context.Context, url string, defaultSpace string, into interface{}) error {
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, url, nil)
+	if err != nil {
+		return err
+	}
+	resp, err := httpClient(ctx).Do(req)
+	if err != nil {
+		return err
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != 200 {
+		return fmt.Errorf("goupnp: got response status %s from %q", resp.Status, url)
+	}
+
+	decoder := xml.NewDecoder(resp.Body)
+	decoder.DefaultSpace = defaultSpace
+	decoder.CharsetReader = CharsetReaderDefault
+
+	return decoder.Decode(into)
+}
--- a/vendor/github.com/tailscale/goupnp/httpu/httpu.go
+++ b/vendor/github.com/tailscale/goupnp/httpu/httpu.go
@@ -0,0 +1,164 @@
+package httpu
+
+import (
+	"bufio"
+	"bytes"
+	"errors"
+	"fmt"
+	"io"
+	"log"
+	"net"
+	"net/http"
+	"sync"
+	"time"
+)
+
+// ClientInterface is the general interface provided to perform HTTP-over-UDP
+// requests.
+type ClientInterface interface {
+	io.Closer
+	// Do performs a request. The timeout is how long to wait for before returning
+	// the responses that were received. An error is only returned for failing to
+	// send the request. Failures in receipt simply do not add to the resulting
+	// responses.
+	Do(req *http.Request, numSends int) ([]*http.Response, error)
+}
+
+// HTTPUClient is a client for dealing with HTTPU (HTTP over UDP). Its typical
+// function is for HTTPMU, and particularly SSDP.
+type HTTPUClient struct {
+	connLock sync.Mutex // Protects use of conn.
+	conn     net.PacketConn
+}
+
+var _ ClientInterface = &HTTPUClient{}
+
+// NewHTTPUClient creates a new HTTPUClient, opening up a new UDP socket for the
+// purpose.
+func NewHTTPUClient() (*HTTPUClient, error) {
+	conn, err := net.ListenPacket("udp", ":0")
+	if err != nil {
+		return nil, err
+	}
+	return &HTTPUClient{conn: conn}, nil
+}
+
+// NewHTTPUClientAddr creates a new HTTPUClient which will broadcast packets
+// from the specified address, opening up a new UDP socket for the purpose
+func NewHTTPUClientAddr(addr string) (*HTTPUClient, error) {
+	ip := net.ParseIP(addr)
+	if ip == nil {
+		return nil, errors.New("Invalid listening address")
+	}
+	conn, err := net.ListenPacket("udp", ip.String()+":0")
+	if err != nil {
+		return nil, err
+	}
+	return &HTTPUClient{conn: conn}, nil
+}
+
+// Close shuts down the client. The client will no longer be useful following
+// this.
+func (httpu *HTTPUClient) Close() error {
+	httpu.connLock.Lock()
+	defer httpu.connLock.Unlock()
+	return httpu.conn.Close()
+}
+
+// Do implements ClientInterface.Do.
+//
+// Note that at present only one concurrent connection will happen per
+// HTTPUClient.
+func (httpu *HTTPUClient) Do(
+	req *http.Request,
+	numSends int,
+) ([]*http.Response, error) {
+	httpu.connLock.Lock()
+	defer httpu.connLock.Unlock()
+
+	// Create the request. This is a subset of what http.Request.Write does
+	// deliberately to avoid creating extra fields which may confuse some
+	// devices.
+	var requestBuf bytes.Buffer
+	method := req.Method
+	if method == "" {
+		method = "GET"
+	}
+	if _, err := fmt.Fprintf(&requestBuf, "%s %s HTTP/1.1\r\n", method, req.URL.RequestURI()); err != nil {
+		return nil, err
+	}
+	if err := req.Header.Write(&requestBuf); err != nil {
+		return nil, err
+	}
+	if _, err := requestBuf.Write([]byte{'\r', '\n'}); err != nil {
+		return nil, err
+	}
+
+	destAddr, err := net.ResolveUDPAddr("udp", req.Host)
+	if err != nil {
+		return nil, err
+	}
+	ctx := req.Context()
+	deadline, ok := ctx.Deadline()
+	if !ok {
+		deadline = time.Now().Add(2 * time.Second)
+	}
+	returned := make(chan struct{})
+	defer close(returned)
+
+	go func() {
+		select {
+		case <-ctx.Done():
+			// if context is cancelled, stop any connections by setting time in the past.
+			httpu.conn.SetDeadline(time.Now().Add(-time.Second))
+		case <-returned:
+		}
+	}()
+	if err = httpu.conn.SetDeadline(deadline); err != nil {
+		return nil, err
+	}
+
+	// Send request.
+	for i := 0; i < numSends; i++ {
+		if n, err := httpu.conn.WriteTo(requestBuf.Bytes(), destAddr); err != nil {
+			return nil, err
+		} else if n < len(requestBuf.Bytes()) {
+			return nil, fmt.Errorf("httpu: wrote %d bytes rather than full %d in request",
+				n, len(requestBuf.Bytes()))
+		}
+		time.Sleep(5 * time.Millisecond)
+	}
+
+	// Await responses until timeout.
+	var responses []*http.Response
+	responseBytes := make([]byte, 2048)
+	for {
+		// 2048 bytes should be sufficient for most networks.
+		n, _, err := httpu.conn.ReadFrom(responseBytes)
+		if err != nil {
+			if err, ok := err.(net.Error); ok {
+				if err.Timeout() {
+					break
+				}
+				if err.Temporary() {
+					// Sleep in case this is a persistent error to avoid pegging CPU until deadline.
+					time.Sleep(10 * time.Millisecond)
+					continue
+				}
+			}
+			return nil, err
+		}
+
+		// Parse response.
+		response, err := http.ReadResponse(bufio.NewReader(bytes.NewBuffer(responseBytes[:n])), req)
+		if err != nil {
+			log.Printf("httpu: error while parsing response: %v", err)
+			continue
+		}
+
+		responses = append(responses, response)
+	}
+
+	// Timeout reached - return discovered responses.
+	return responses, nil
+}
--- a/vendor/github.com/tailscale/goupnp/httpu/multiclient.go
+++ b/vendor/github.com/tailscale/goupnp/httpu/multiclient.go
@@ -0,0 +1,72 @@
+package httpu
+
+import (
+	"net/http"
+
+	"golang.org/x/sync/errgroup"
+)
+
+// MultiClient dispatches requests out to all the delegated clients.
+type MultiClient struct {
+	// The HTTPU clients to delegate to.
+	delegates []ClientInterface
+}
+
+var _ ClientInterface = &MultiClient{}
+
+// NewMultiClient creates a new MultiClient that delegates to all the given
+// clients.
+func NewMultiClient(delegates []ClientInterface) *MultiClient {
+	return &MultiClient{delegates: delegates}
+}
+
+func (mc *MultiClient) Close() error {
+	for _, d := range mc.delegates {
+		d.Close()
+	}
+	return nil
+}
+
+// Do implements ClientInterface.Do.
+func (mc *MultiClient) Do(
+	req *http.Request,
+	numSends int,
+) ([]*http.Response, error) {
+	tasks := &errgroup.Group{}
+
+	results := make(chan []*http.Response)
+	tasks.Go(func() error {
+		defer close(results)
+		return mc.sendRequests(results, req, numSends)
+	})
+
+	var responses []*http.Response
+	tasks.Go(func() error {
+		for rs := range results {
+			responses = append(responses, rs...)
+		}
+		return nil
+	})
+
+	return responses, tasks.Wait()
+}
+
+func (mc *MultiClient) sendRequests(
+	results chan<- []*http.Response,
+	req *http.Request,
+	numSends int,
+) error {
+	tasks := &errgroup.Group{}
+	for _, d := range mc.delegates {
+		d := d // copy for closure
+		tasks.Go(func() error {
+			responses, err := d.Do(req, numSends)
+			if err != nil {
+				return err
+			}
+			results <- responses
+			return nil
+		})
+	}
+	return tasks.Wait()
+}
--- a/vendor/github.com/tailscale/goupnp/httpu/serve.go
+++ b/vendor/github.com/tailscale/goupnp/httpu/serve.go
@@ -0,0 +1,108 @@
+package httpu
+
+import (
+	"bufio"
+	"bytes"
+	"log"
+	"net"
+	"net/http"
+	"regexp"
+)
+
+const (
+	DefaultMaxMessageBytes = 2048
+)
+
+var (
+	trailingWhitespaceRx = regexp.MustCompile(" +\r\n")
+	crlf                 = []byte("\r\n")
+)
+
+// Handler is the interface by which received HTTPU messages are passed to
+// handling code.
+type Handler interface {
+	// ServeMessage is called for each HTTPU message received. peerAddr contains
+	// the address that the message was received from.
+	ServeMessage(r *http.Request)
+}
+
+// HandlerFunc is a function-to-Handler adapter.
+type HandlerFunc func(r *http.Request)
+
+func (f HandlerFunc) ServeMessage(r *http.Request) {
+	f(r)
+}
+
+// A Server defines parameters for running an HTTPU server.
+type Server struct {
+	Addr            string         // UDP address to listen on
+	Multicast       bool           // Should listen for multicast?
+	Interface       *net.Interface // Network interface to listen on for multicast, nil for default multicast interface
+	Handler         Handler        // handler to invoke
+	MaxMessageBytes int            // maximum number of bytes to read from a packet, DefaultMaxMessageBytes if 0
+}
+
+// ListenAndServe listens on the UDP network address srv.Addr. If srv.Multicast
+// is true, then a multicast UDP listener will be used on srv.Interface (or
+// default interface if nil).
+func (srv *Server) ListenAndServe() error {
+	var err error
+
+	var addr *net.UDPAddr
+	if addr, err = net.ResolveUDPAddr("udp", srv.Addr); err != nil {
+		log.Fatal(err)
+	}
+
+	var conn net.PacketConn
+	if srv.Multicast {
+		if conn, err = net.ListenMulticastUDP("udp", srv.Interface, addr); err != nil {
+			return err
+		}
+	} else {
+		if conn, err = net.ListenUDP("udp", addr); err != nil {
+			return err
+		}
+	}
+
+	return srv.Serve(conn)
+}
+
+// Serve messages received on the given packet listener to the srv.Handler.
+func (srv *Server) Serve(l net.PacketConn) error {
+	maxMessageBytes := DefaultMaxMessageBytes
+	if srv.MaxMessageBytes != 0 {
+		maxMessageBytes = srv.MaxMessageBytes
+	}
+	for {
+		buf := make([]byte, maxMessageBytes)
+		n, peerAddr, err := l.ReadFrom(buf)
+		if err != nil {
+			return err
+		}
+		buf = buf[:n]
+
+		go func(buf []byte, peerAddr net.Addr) {
+			// At least one router's UPnP implementation has added a trailing space
+			// after "HTTP/1.1" - trim it.
+			buf = trailingWhitespaceRx.ReplaceAllLiteral(buf, crlf)
+
+			req, err := http.ReadRequest(bufio.NewReader(bytes.NewBuffer(buf)))
+			if err != nil {
+				log.Printf("httpu: Failed to parse request: %v", err)
+				return
+			}
+			req.RemoteAddr = peerAddr.String()
+			srv.Handler.ServeMessage(req)
+			// No need to call req.Body.Close - underlying reader is bytes.Buffer.
+		}(buf, peerAddr)
+	}
+}
+
+// Serve messages received on the given packet listener to the given handler.
+func Serve(l net.PacketConn, handler Handler) error {
+	srv := Server{
+		Handler:         handler,
+		MaxMessageBytes: DefaultMaxMessageBytes,
+	}
+	return srv.Serve(l)
+}
--- a/vendor/github.com/tailscale/goupnp/network.go
+++ b/vendor/github.com/tailscale/goupnp/network.go
@@ -0,0 +1,65 @@
+package goupnp
+
+import (
+	"net"
+
+	"github.com/tailscale/goupnp/httpu"
+)
+
+// httpuClient creates a HTTPU client that multiplexes to all multicast-capable
+// IPv4 addresses on the host. Returns a function to clean up once the client is
+// no longer required.
+func httpuClient() (*httpu.MultiClient, error) {
+	addrs, err := localIPv4MCastAddrs()
+	if err != nil {
+		return nil, ctxError(err, "requesting host IPv4 addresses")
+	}
+
+	delegates := make([]httpu.ClientInterface, 0, len(addrs))
+	for _, addr := range addrs {
+		c, err := httpu.NewHTTPUClientAddr(addr)
+		if err != nil {
+			return nil, ctxErrorf(err, "creating HTTPU client for address %s", addr)
+		}
+		delegates = append(delegates, c)
+	}
+
+	return httpu.NewMultiClient(delegates), nil
+}
+
+// localIPv2MCastAddrs returns the set of IPv4 addresses on multicast-able
+// network interfaces.
+func localIPv4MCastAddrs() ([]string, error) {
+	ifaces, err := net.Interfaces()
+	if err != nil {
+		return nil, ctxError(err, "requesting host interfaces")
+	}
+
+	// Find the set of addresses to listen on.
+	var addrs []string
+	for _, iface := range ifaces {
+		if iface.Flags&net.FlagMulticast == 0 || iface.Flags&net.FlagLoopback != 0 || iface.Flags&net.FlagUp == 0 {
+			// Does not support multicast or is a loopback address.
+			continue
+		}
+		ifaceAddrs, err := iface.Addrs()
+		if err != nil {
+			return nil, ctxErrorf(err,
+				"finding addresses on interface %s", iface.Name)
+		}
+		for _, netAddr := range ifaceAddrs {
+			addr, ok := netAddr.(*net.IPNet)
+			if !ok {
+				// Not an IPNet address.
+				continue
+			}
+			if addr.IP.To4() == nil {
+				// Not IPv4.
+				continue
+			}
+			addrs = append(addrs, addr.IP.String())
+		}
+	}
+
+	return addrs, nil
+}
--- a/vendor/github.com/tailscale/goupnp/scpd/scpd.go
+++ b/vendor/github.com/tailscale/goupnp/scpd/scpd.go
@@ -0,0 +1,167 @@
+package scpd
+
+import (
+	"encoding/xml"
+	"strings"
+)
+
+const (
+	SCPDXMLNamespace = "urn:schemas-upnp-org:service-1-0"
+)
+
+func cleanWhitespace(s *string) {
+	*s = strings.TrimSpace(*s)
+}
+
+// SCPD is the service description as described by section 2.5 "Service
+// description" in
+// http://upnp.org/specs/arch/UPnP-arch-DeviceArchitecture-v1.1.pdf
+type SCPD struct {
+	XMLName        xml.Name        `xml:"scpd"`
+	ConfigId       string          `xml:"configId,attr"`
+	SpecVersion    SpecVersion     `xml:"specVersion"`
+	Actions        []Action        `xml:"actionList>action"`
+	StateVariables []StateVariable `xml:"serviceStateTable>stateVariable"`
+}
+
+// Clean attempts to remove stray whitespace etc. in the structure. It seems
+// unfortunately common for stray whitespace to be present in SCPD documents,
+// this method attempts to make it easy to clean them out.
+func (scpd *SCPD) Clean() {
+	cleanWhitespace(&scpd.ConfigId)
+	for i := range scpd.Actions {
+		scpd.Actions[i].clean()
+	}
+	for i := range scpd.StateVariables {
+		scpd.StateVariables[i].clean()
+	}
+}
+
+func (scpd *SCPD) GetStateVariable(variable string) *StateVariable {
+	for i := range scpd.StateVariables {
+		v := &scpd.StateVariables[i]
+		if v.Name == variable {
+			return v
+		}
+	}
+	return nil
+}
+
+func (scpd *SCPD) GetAction(action string) *Action {
+	for i := range scpd.Actions {
+		a := &scpd.Actions[i]
+		if a.Name == action {
+			return a
+		}
+	}
+	return nil
+}
+
+// SpecVersion is part of a SCPD document, describes the version of the
+// specification that the data adheres to.
+type SpecVersion struct {
+	Major int32 `xml:"major"`
+	Minor int32 `xml:"minor"`
+}
+
+type Action struct {
+	Name      string     `xml:"name"`
+	Arguments []Argument `xml:"argumentList>argument"`
+}
+
+func (action *Action) clean() {
+	cleanWhitespace(&action.Name)
+	for i := range action.Arguments {
+		action.Arguments[i].clean()
+	}
+}
+
+func (action *Action) InputArguments() []*Argument {
+	var result []*Argument
+	for i := range action.Arguments {
+		arg := &action.Arguments[i]
+		if arg.IsInput() {
+			result = append(result, arg)
+		}
+	}
+	return result
+}
+
+func (action *Action) OutputArguments() []*Argument {
+	var result []*Argument
+	for i := range action.Arguments {
+		arg := &action.Arguments[i]
+		if arg.IsOutput() {
+			result = append(result, arg)
+		}
+	}
+	return result
+}
+
+type Argument struct {
+	Name                 string `xml:"name"`
+	Direction            string `xml:"direction"`            // in|out
+	RelatedStateVariable string `xml:"relatedStateVariable"` // ?
+	Retval               string `xml:"retval"`               // ?
+}
+
+func (arg *Argument) clean() {
+	cleanWhitespace(&arg.Name)
+	cleanWhitespace(&arg.Direction)
+	cleanWhitespace(&arg.RelatedStateVariable)
+	cleanWhitespace(&arg.Retval)
+}
+
+func (arg *Argument) IsInput() bool {
+	return arg.Direction == "in"
+}
+
+func (arg *Argument) IsOutput() bool {
+	return arg.Direction == "out"
+}
+
+type StateVariable struct {
+	Name              string             `xml:"name"`
+	SendEvents        string             `xml:"sendEvents,attr"` // yes|no
+	Multicast         string             `xml:"multicast,attr"`  // yes|no
+	DataType          DataType           `xml:"dataType"`
+	DefaultValue      string             `xml:"defaultValue"`
+	AllowedValueRange *AllowedValueRange `xml:"allowedValueRange"`
+	AllowedValues     []string           `xml:"allowedValueList>allowedValue"`
+}
+
+func (v *StateVariable) clean() {
+	cleanWhitespace(&v.Name)
+	cleanWhitespace(&v.SendEvents)
+	cleanWhitespace(&v.Multicast)
+	v.DataType.clean()
+	cleanWhitespace(&v.DefaultValue)
+	if v.AllowedValueRange != nil {
+		v.AllowedValueRange.clean()
+	}
+	for i := range v.AllowedValues {
+		cleanWhitespace(&v.AllowedValues[i])
+	}
+}
+
+type AllowedValueRange struct {
+	Minimum string `xml:"minimum"`
+	Maximum string `xml:"maximum"`
+	Step    string `xml:"step"`
+}
+
+func (r *AllowedValueRange) clean() {
+	cleanWhitespace(&r.Minimum)
+	cleanWhitespace(&r.Maximum)
+	cleanWhitespace(&r.Step)
+}
+
+type DataType struct {
+	Name string `xml:",chardata"`
+	Type string `xml:"type,attr"`
+}
+
+func (dt *DataType) clean() {
+	cleanWhitespace(&dt.Name)
+	cleanWhitespace(&dt.Type)
+}
--- a/vendor/github.com/tailscale/goupnp/service_client.go
+++ b/vendor/github.com/tailscale/goupnp/service_client.go
@@ -0,0 +1,88 @@
+package goupnp
+
+import (
+	"context"
+	"fmt"
+	"net/url"
+
+	"github.com/tailscale/goupnp/soap"
+)
+
+// ServiceClient is a SOAP client, root device and the service for the SOAP
+// client rolled into one value. The root device, location, and service are
+// intended to be informational. Location can be used to later recreate a
+// ServiceClient with NewServiceClientByURL if the service is still present;
+// bypassing the discovery process.
+type ServiceClient struct {
+	SOAPClient *soap.SOAPClient
+	RootDevice *RootDevice
+	Location   *url.URL
+	Service    *Service
+}
+
+// NewServiceClients discovers services, and returns clients for them. err will
+// report any error with the discovery process (blocking any device/service
+// discovery), errors reports errors on a per-root-device basis.
+func NewServiceClients(ctx context.Context, searchTarget string) (clients []ServiceClient, errors []error, err error) {
+	var maybeRootDevices []MaybeRootDevice
+	if maybeRootDevices, err = DiscoverDevices(ctx, searchTarget); err != nil {
+		return
+	}
+
+	clients = make([]ServiceClient, 0, len(maybeRootDevices))
+
+	for _, maybeRootDevice := range maybeRootDevices {
+		if maybeRootDevice.Err != nil {
+			errors = append(errors, maybeRootDevice.Err)
+			continue
+		}
+
+		deviceClients, err := NewServiceClientsFromRootDevice(ctx, maybeRootDevice.Root, maybeRootDevice.Location, searchTarget)
+		if err != nil {
+			errors = append(errors, err)
+			continue
+		}
+		clients = append(clients, deviceClients...)
+	}
+
+	return
+}
+
+// NewServiceClientsByURL creates client(s) for the given service URN, for a
+// root device at the given URL.
+func NewServiceClientsByURL(ctx context.Context, loc *url.URL, searchTarget string) ([]ServiceClient, error) {
+	rootDevice, err := DeviceByURL(ctx, loc)
+	if err != nil {
+		return nil, err
+	}
+	return NewServiceClientsFromRootDevice(ctx, rootDevice, loc, searchTarget)
+}
+
+// NewServiceClientsFromDevice creates client(s) for the given service URN, in
+// a given root device. The loc parameter is simply assigned to the
+// Location attribute of the returned ServiceClient(s).
+func NewServiceClientsFromRootDevice(ctx context.Context, rootDevice *RootDevice, loc *url.URL, searchTarget string) ([]ServiceClient, error) {
+	device := &rootDevice.Device
+	srvs := device.FindService(ctx, searchTarget)
+	if len(srvs) == 0 {
+		return nil, fmt.Errorf("goupnp: service %q not found within device %q (UDN=%q)",
+			searchTarget, device.FriendlyName, device.UDN)
+	}
+	clients := make([]ServiceClient, 0, len(srvs))
+	for _, srv := range srvs {
+		clients = append(clients, ServiceClient{
+			SOAPClient: srv.NewSOAPClient(httpClient(ctx)),
+			RootDevice: rootDevice,
+			Location:   loc,
+			Service:    srv,
+		})
+	}
+	return clients, nil
+}
+
+// GetServiceClient returns the ServiceClient itself. This is provided so that the
+// service client attributes can be accessed via an interface method on a
+// wrapping type.
+func (client *ServiceClient) GetServiceClient() *ServiceClient {
+	return client
+}
--- a/vendor/github.com/tailscale/goupnp/soap/soap.go
+++ b/vendor/github.com/tailscale/goupnp/soap/soap.go
@@ -0,0 +1,192 @@
+// Definition for the SOAP structure required for UPnP's SOAP usage.
+
+package soap
+
+import (
+	"bytes"
+	"context"
+	"encoding/xml"
+	"fmt"
+	"io/ioutil"
+	"net/http"
+	"net/url"
+	"reflect"
+	"strings"
+)
+
+const (
+	soapEncodingStyle = "http://schemas.xmlsoap.org/soap/encoding/"
+	soapPrefix        = xml.Header + `<s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/" s:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/"><s:Body>`
+	soapSuffix        = `</s:Body></s:Envelope>`
+)
+
+type SOAPClient struct {
+	EndpointURL url.URL
+	HTTPClient  *http.Client
+}
+
+// NewSoapClient creates a new soap client to a specific URL using a given http.Client.
+// The http.Client must not be nil.
+func NewSOAPClient(endpointURL url.URL, httpClient *http.Client) *SOAPClient {
+	return &SOAPClient{
+		EndpointURL: endpointURL,
+		HTTPClient:  httpClient,
+	}
+}
+
+// PerformSOAPAction makes a SOAP request, with the given action.
+// inAction and outAction must both be pointers to structs with string fields
+// only.
+func (client *SOAPClient) PerformAction(
+	ctx context.Context, actionNamespace, actionName string,
+	inAction interface{}, outAction interface{},
+) error {
+	requestBytes, err := encodeRequestAction(actionNamespace, actionName, inAction)
+	if err != nil {
+		return err
+	}
+
+	req := &http.Request{
+		Method: "POST",
+		URL:    &client.EndpointURL,
+		Header: http.Header{
+			"SOAPACTION":   []string{`"` + actionNamespace + "#" + actionName + `"`},
+			"CONTENT-TYPE": []string{"text/xml; charset=\"utf-8\""},
+		},
+		Body: ioutil.NopCloser(bytes.NewBuffer(requestBytes)),
+		// Set ContentLength to avoid chunked encoding - some servers might not support it.
+		ContentLength: int64(len(requestBytes)),
+	}
+
+	response, err := client.HTTPClient.Do(req.WithContext(ctx))
+	if err != nil {
+		return fmt.Errorf("goupnp: error performing SOAP HTTP request: %v", err)
+	}
+	defer response.Body.Close()
+	if response.StatusCode != 200 && response.ContentLength == 0 {
+		return fmt.Errorf("goupnp: SOAP request got HTTP %s", response.Status)
+	}
+
+	responseEnv := newSOAPEnvelope()
+	decoder := xml.NewDecoder(response.Body)
+	if err := decoder.Decode(responseEnv); err != nil {
+		return fmt.Errorf("goupnp: error decoding response body: %v", err)
+	}
+
+	if responseEnv.Body.Fault != nil {
+		return responseEnv.Body.Fault
+	} else if response.StatusCode != 200 {
+		return fmt.Errorf("goupnp: SOAP request got HTTP %s", response.Status)
+	}
+
+	if outAction == nil {
+		return nil
+	}
+	if err := xml.Unmarshal(responseEnv.Body.RawAction, outAction); err != nil {
+		return fmt.Errorf("goupnp: error unmarshalling out action: %v, %v", err, responseEnv.Body.RawAction)
+	}
+	return nil
+}
+
+// newSOAPAction creates a soapEnvelope with the given action and arguments.
+func newSOAPEnvelope() *soapEnvelope {
+	return &soapEnvelope{EncodingStyle: soapEncodingStyle}
+}
+
+// encodeRequestAction is a hacky way to create an encoded SOAP envelope
+// containing the given action. Experiments with one router have shown that it
+// 500s for requests where the outer default xmlns is set to the SOAP
+// namespace, and then reassigning the default namespace within that to the
+// service namespace. Hand-coding the outer XML to work-around this.
+func encodeRequestAction(actionNamespace, actionName string, inAction interface{}) ([]byte, error) {
+	requestBuf := new(bytes.Buffer)
+	requestBuf.WriteString(soapPrefix)
+	requestBuf.WriteString(`<u:`)
+	xml.EscapeText(requestBuf, []byte(actionName))
+	requestBuf.WriteString(` xmlns:u="`)
+	xml.EscapeText(requestBuf, []byte(actionNamespace))
+	requestBuf.WriteString(`">`)
+	if inAction != nil {
+		if err := encodeRequestArgs(requestBuf, inAction); err != nil {
+			return nil, err
+		}
+	}
+	requestBuf.WriteString(`</u:`)
+	xml.EscapeText(requestBuf, []byte(actionName))
+	requestBuf.WriteString(`>`)
+	requestBuf.WriteString(soapSuffix)
+	return requestBuf.Bytes(), nil
+}
+
+func encodeRequestArgs(w *bytes.Buffer, inAction interface{}) error {
+	in := reflect.Indirect(reflect.ValueOf(inAction))
+	if in.Kind() != reflect.Struct {
+		return fmt.Errorf("goupnp: SOAP inAction is not a struct but of type %v", in.Type())
+	}
+	enc := xml.NewEncoder(w)
+	nFields := in.NumField()
+	inType := in.Type()
+	for i := 0; i < nFields; i++ {
+		field := inType.Field(i)
+		argName := field.Name
+		if nameOverride := field.Tag.Get("soap"); nameOverride != "" {
+			argName = nameOverride
+		}
+		value := in.Field(i)
+		if value.Kind() != reflect.String {
+			return fmt.Errorf("goupnp: SOAP arg %q is not of type string, but of type %v", argName, value.Type())
+		}
+		elem := xml.StartElement{Name: xml.Name{Local: argName}}
+		if err := enc.EncodeToken(elem); err != nil {
+			return fmt.Errorf("goupnp: error encoding start element for SOAP arg %q: %v", argName, err)
+		}
+		if err := enc.Flush(); err != nil {
+			return fmt.Errorf("goupnp: error flushing start element for SOAP arg %q: %v", argName, err)
+		}
+		if _, err := w.Write([]byte(escapeXMLText(value.Interface().(string)))); err != nil {
+			return fmt.Errorf("goupnp: error writing value for SOAP arg %q: %v", argName, err)
+		}
+		if err := enc.EncodeToken(elem.End()); err != nil {
+			return fmt.Errorf("goupnp: error encoding end element for SOAP arg %q: %v", argName, err)
+		}
+	}
+	enc.Flush()
+	return nil
+}
+
+var replacer = strings.NewReplacer("<", "&lt;", ">", "&gt;", "&", "&amp;")
+
+// escapeXMLText is used by generated code to escape text in XML, but only
+// escaping the characters `<`, `>`, and `&`.
+//
+// This is provided in order to work around SOAP server implementations that
+// fail to decode XML correctly, specifically failing to decode `"`, `'`. Note
+// that this can only be safely used for injecting into XML text, but not into
+// attributes or other contexts.
+func escapeXMLText(s string) string {
+	return replacer.Replace(s)
+}
+
+type soapEnvelope struct {
+	XMLName       xml.Name `xml:"http://schemas.xmlsoap.org/soap/envelope/ Envelope"`
+	EncodingStyle string   `xml:"http://schemas.xmlsoap.org/soap/envelope/ encodingStyle,attr"`
+	Body          soapBody `xml:"http://schemas.xmlsoap.org/soap/envelope/ Body"`
+}
+
+type soapBody struct {
+	Fault     *SOAPFaultError `xml:"Fault"`
+	RawAction []byte          `xml:",innerxml"`
+}
+
+// SOAPFaultError implements error, and contains SOAP fault information.
+type SOAPFaultError struct {
+	FaultCode   string `xml:"faultCode"`
+	FaultString string `xml:"faultString"`
+	Detail      struct {
+		Raw []byte `xml:",innerxml"`
+	} `xml:"detail"`
+}
+
+func (err *SOAPFaultError) Error() string {
+	return fmt.Sprintf("SOAP fault: %s", err.FaultString)
+}
--- a/vendor/github.com/tailscale/goupnp/soap/types.go
+++ b/vendor/github.com/tailscale/goupnp/soap/types.go
@@ -0,0 +1,490 @@
+package soap
+
+import (
+	"encoding/base64"
+	"encoding/hex"
+	"errors"
+	"fmt"
+	"net/url"
+	"strconv"
+	"strings"
+	"time"
+	"unicode/utf8"
+)
+
+var (
+	// localLoc acts like time.Local for this package, but is faked out by the
+	// unit tests to ensure that things stay constant (especially when running
+	// this test in a place where local time is UTC which might mask bugs).
+	localLoc = time.Local
+)
+
+func MarshalUi1(v uint8) (string, error) {
+	return strconv.FormatUint(uint64(v), 10), nil
+}
+
+func UnmarshalUi1(s string) (uint8, error) {
+	v, err := strconv.ParseUint(s, 10, 8)
+	return uint8(v), err
+}
+
+func MarshalUi2(v uint16) (string, error) {
+	return strconv.FormatUint(uint64(v), 10), nil
+}
+
+func UnmarshalUi2(s string) (uint16, error) {
+	v, err := strconv.ParseUint(s, 10, 16)
+	return uint16(v), err
+}
+
+func MarshalUi4(v uint32) (string, error) {
+	return strconv.FormatUint(uint64(v), 10), nil
+}
+
+func UnmarshalUi4(s string) (uint32, error) {
+	v, err := strconv.ParseUint(s, 10, 32)
+	return uint32(v), err
+}
+
+func MarshalUi8(v uint64) (string, error) {
+	return strconv.FormatUint(v, 10), nil
+}
+
+func UnmarshalUi8(s string) (uint64, error) {
+	v, err := strconv.ParseUint(s, 10, 64)
+	return uint64(v), err
+}
+
+func MarshalI1(v int8) (string, error) {
+	return strconv.FormatInt(int64(v), 10), nil
+}
+
+func UnmarshalI1(s string) (int8, error) {
+	v, err := strconv.ParseInt(s, 10, 8)
+	return int8(v), err
+}
+
+func MarshalI2(v int16) (string, error) {
+	return strconv.FormatInt(int64(v), 10), nil
+}
+
+func UnmarshalI2(s string) (int16, error) {
+	v, err := strconv.ParseInt(s, 10, 16)
+	return int16(v), err
+}
+
+func MarshalI4(v int32) (string, error) {
+	return strconv.FormatInt(int64(v), 10), nil
+}
+
+func UnmarshalI4(s string) (int32, error) {
+	v, err := strconv.ParseInt(s, 10, 32)
+	return int32(v), err
+}
+
+func MarshalInt(v int64) (string, error) {
+	return strconv.FormatInt(v, 10), nil
+}
+
+func UnmarshalInt(s string) (int64, error) {
+	return strconv.ParseInt(s, 10, 64)
+}
+
+func MarshalR4(v float32) (string, error) {
+	return strconv.FormatFloat(float64(v), 'G', -1, 32), nil
+}
+
+func UnmarshalR4(s string) (float32, error) {
+	v, err := strconv.ParseFloat(s, 32)
+	return float32(v), err
+}
+
+func MarshalR8(v float64) (string, error) {
+	return strconv.FormatFloat(v, 'G', -1, 64), nil
+}
+
+func UnmarshalR8(s string) (float64, error) {
+	v, err := strconv.ParseFloat(s, 64)
+	return float64(v), err
+}
+
+// MarshalFixed14_4 marshals float64 to SOAP "fixed.14.4" type.
+func MarshalFixed14_4(v float64) (string, error) {
+	if v >= 1e14 || v <= -1e14 {
+		return "", fmt.Errorf("soap fixed14.4: value %v out of bounds", v)
+	}
+	return strconv.FormatFloat(v, 'f', 4, 64), nil
+}
+
+// UnmarshalFixed14_4 unmarshals float64 from SOAP "fixed.14.4" type.
+func UnmarshalFixed14_4(s string) (float64, error) {
+	v, err := strconv.ParseFloat(s, 64)
+	if err != nil {
+		return 0, err
+	}
+	if v >= 1e14 || v <= -1e14 {
+		return 0, fmt.Errorf("soap fixed14.4: value %q out of bounds", s)
+	}
+	return v, nil
+}
+
+// MarshalChar marshals rune to SOAP "char" type.
+func MarshalChar(v rune) (string, error) {
+	if v == 0 {
+		return "", errors.New("soap char: rune 0 is not allowed")
+	}
+	return string(v), nil
+}
+
+// UnmarshalChar unmarshals rune from SOAP "char" type.
+func UnmarshalChar(s string) (rune, error) {
+	if len(s) == 0 {
+		return 0, errors.New("soap char: got empty string")
+	}
+	r, n := utf8.DecodeRune([]byte(s))
+	if n != len(s) {
+		return 0, fmt.Errorf("soap char: value %q is not a single rune", s)
+	}
+	return r, nil
+}
+
+func MarshalString(v string) (string, error) {
+	return v, nil
+}
+
+func UnmarshalString(v string) (string, error) {
+	return v, nil
+}
+
+func parseInt(s string, err *error) int {
+	v, parseErr := strconv.ParseInt(s, 10, 64)
+	if parseErr != nil {
+		*err = parseErr
+	}
+	return int(v)
+}
+
+var dateLayouts = []string{
+	"2006-01-02",
+	"20060102",
+
+	"2006-01",
+	"200601",
+
+	"2006",
+}
+
+func parseDateParts(s string) (year, month, day int, err error) {
+	var parsed time.Time
+	for _, layout := range dateLayouts {
+		parsed, err = time.Parse(layout, s)
+		if err == nil {
+			break
+		}
+	}
+	if err != nil {
+		err = fmt.Errorf("soap date: value %q is not in a recognized ISO8601 date format", s)
+		return
+	}
+	year = int(parsed.Year())
+	month = int(parsed.Month())
+	day = int(parsed.Day())
+	return
+}
+
+var timeLayouts = []string{
+	"15:04:05",
+	"150405",
+
+	"15:04",
+	"1504",
+
+	"15",
+}
+
+func parseTimeParts(s string) (hour, minute, second int, err error) {
+	// special case 24 hour time limit
+	if s == "24:00:00" {
+		return 24, 0, 0, nil
+	}
+	var parsed time.Time
+	for _, layout := range timeLayouts {
+		parsed, err = time.Parse(layout, s)
+		if err == nil {
+			break
+		}
+	}
+	if err != nil {
+		err = fmt.Errorf("soap time: value %q is not in ISO8601 time format", s)
+		return
+	}
+
+	hour = parsed.Hour()
+	minute = parsed.Minute()
+	second = parsed.Second()
+	return
+}
+
+// (+|-)hh[[:]mm]
+var timezoneLayouts = []string{
+	"+07:00",
+	"-07:00",
+
+	"+0700",
+	"-0700",
+
+	"+07",
+	"-07",
+}
+
+func parseTimezone(s string) (loc *time.Location, err error) {
+	if s == "Z" {
+		return time.UTC, nil
+	}
+	var parsed time.Time
+	for _, layout := range timezoneLayouts {
+		parsed, err = time.Parse(layout, s)
+		if err == nil {
+			break
+		}
+	}
+	if err != nil {
+		err = fmt.Errorf("soap timezone: value %q is not in ISO8601 timezone format", s)
+		return
+	}
+	return parsed.Location(), nil
+}
+
+// splitCompleteDateTimeZone splits date, time and timezone apart from an
+// ISO8601 string. It does not ensure that the contents of each part are
+// correct, it merely splits on certain delimiters.
+// e.g "2010-09-08T12:15:10+0700" => "2010-09-08", "12:15:10", "+0700".
+// Timezone can only be present if time is also present.
+func splitCompleteDateTimeZone(s string) (dateStr, timeStr, zoneStr string) {
+	dateIndex := strings.Index(s, "T")
+	if dateIndex == -1 {
+		dateStr = s
+		return
+	}
+	dateStr = s[:dateIndex]
+	zoneIndex := strings.IndexAny(s[dateIndex:], "Z+-")
+	if zoneIndex == -1 {
+		timeStr = s[dateIndex+1:]
+		return
+	}
+	timeStr = s[dateIndex+1 : dateIndex+zoneIndex]
+	zoneStr = s[dateIndex+zoneIndex:]
+	return
+}
+
+// MarshalDate marshals time.Time to SOAP "date" type. Note that this converts
+// to local time, and discards the time-of-day components.
+func MarshalDate(v time.Time) (string, error) {
+	return v.In(localLoc).Format("2006-01-02"), nil
+}
+
+var dateFmts = []string{"2006-01-02", "20060102"}
+
+// UnmarshalDate unmarshals time.Time from SOAP "date" type. This outputs the
+// date as midnight in the local time zone.
+func UnmarshalDate(s string) (time.Time, error) {
+	year, month, day, err := parseDateParts(s)
+	if err != nil {
+		return time.Time{}, err
+	}
+	return time.Date(year, time.Month(month), day, 0, 0, 0, 0, localLoc), nil
+}
+
+// TimeOfDay is used in cases where SOAP "time" or "time.tz" is used.
+type TimeOfDay struct {
+	// Duration of time since midnight.
+	FromMidnight time.Duration
+
+	// Offset is non-zero only if time.tz is used. It is otherwise ignored. If
+	// non-zero, then it is regarded as a UTC offset in seconds. Note that the
+	// sub-minutes is ignored by the marshal function.
+	Location *time.Location
+}
+
+// MarshalTimeOfDay marshals TimeOfDay to the "time" type.
+func MarshalTimeOfDay(v TimeOfDay) (string, error) {
+	d := int64(v.FromMidnight / time.Second)
+	hour := d / 3600
+	d = d % 3600
+	minute := d / 60
+	second := d % 60
+
+	return fmt.Sprintf("%02d:%02d:%02d", hour, minute, second), nil
+}
+
+// UnmarshalTimeOfDay unmarshals TimeOfDay from the "time" type.
+func UnmarshalTimeOfDay(s string) (TimeOfDay, error) {
+	t, err := UnmarshalTimeOfDayTz(s)
+	if err != nil {
+		return t, err
+	} else if t.Location != time.UTC {
+		return t, fmt.Errorf("soap time: value %q contains unexpected timezone", s)
+	}
+	return t, nil
+}
+
+// MarshalTimeOfDayTz marshals TimeOfDay to the "time.tz" type.
+func MarshalTimeOfDayTz(v TimeOfDay) (string, error) {
+	d := int64(v.FromMidnight / time.Second)
+	hour := d / 3600
+	d = d % 3600
+	minute := d / 60
+	second := d % 60
+	if v.Location == nil {
+		t := time.Date(0, 0, 0, int(hour), int(minute), int(second), 0, time.UTC)
+		return t.Format("15:04:05"), nil
+	}
+	t := time.Date(0, 0, 0, int(hour), int(minute), int(second), 0, v.Location)
+	return t.Format("15:04:05Z07:00"), nil
+}
+
+// UnmarshalTimeOfDayTz unmarshals TimeOfDay from the "time.tz" type.
+func UnmarshalTimeOfDayTz(s string) (tod TimeOfDay, err error) {
+	zoneIndex := strings.IndexAny(s, "Z+-")
+	var timePart string
+	loc := time.UTC
+	if zoneIndex == -1 {
+		timePart = s
+	} else {
+		timePart = s[:zoneIndex]
+		if loc, err = parseTimezone(s[zoneIndex:]); err != nil {
+			return
+		}
+	}
+
+	hour, minute, second, err := parseTimeParts(timePart)
+	if err != nil {
+		return
+	}
+
+	fromMidnight := time.Duration(hour*3600+minute*60+second) * time.Second
+
+	// ISO8601 special case - values up to 24:00:00 are allowed, so using
+	// strictly greater-than for the maximum value.
+	if fromMidnight > 24*time.Hour || minute >= 60 || second >= 60 {
+		return TimeOfDay{Location: localLoc}, fmt.Errorf("soap time.tz: value %q has value(s) out of range", s)
+	}
+
+	return TimeOfDay{
+		FromMidnight: time.Duration(hour*3600+minute*60+second) * time.Second,
+		Location:     loc,
+	}, nil
+}
+
+// MarshalDateTime marshals time.Time to SOAP "dateTime" type. Note that this
+// converts to local time.
+func MarshalDateTime(v time.Time) (string, error) {
+	return v.In(localLoc).Format("2006-01-02T15:04:05"), nil
+}
+
+// UnmarshalDateTime unmarshals time.Time from the SOAP "dateTime" type. This
+// returns a value in the local timezone.
+func UnmarshalDateTime(s string) (result time.Time, err error) {
+	dateStr, timeStr, zoneStr := splitCompleteDateTimeZone(s)
+
+	if len(zoneStr) != 0 {
+		err = fmt.Errorf("soap datetime: unexpected timezone in %q", s)
+		return
+	}
+
+	year, month, day, err := parseDateParts(dateStr)
+	if err != nil {
+		return
+	}
+
+	var hour, minute, second int
+	if len(timeStr) != 0 {
+		hour, minute, second, err = parseTimeParts(timeStr)
+		if err != nil {
+			return
+		}
+	}
+
+	result = time.Date(year, time.Month(month), day, hour, minute, second, 0, localLoc)
+	return
+}
+
+// MarshalDateTimeTz marshals time.Time to SOAP "dateTime.tz" type.
+func MarshalDateTimeTz(v time.Time) (string, error) {
+	return v.Format("2006-01-02T15:04:05-07:00"), nil
+}
+
+// UnmarshalDateTimeTz unmarshals time.Time from the SOAP "dateTime.tz" type.
+// This returns a value in the local timezone when the timezone is unspecified.
+func UnmarshalDateTimeTz(s string) (result time.Time, err error) {
+	dateStr, timeStr, zoneStr := splitCompleteDateTimeZone(s)
+
+	year, month, day, err := parseDateParts(dateStr)
+	if err != nil {
+		return
+	}
+
+	var hour, minute, second int
+	location := localLoc
+	if len(timeStr) != 0 {
+		hour, minute, second, err = parseTimeParts(timeStr)
+		if err != nil {
+			return
+		}
+		if len(zoneStr) != 0 {
+			location, err = parseTimezone(zoneStr)
+		}
+	}
+
+	result = time.Date(year, time.Month(month), day, hour, minute, second, 0, location)
+	return
+}
+
+// MarshalBoolean marshals bool to SOAP "boolean" type.
+func MarshalBoolean(v bool) (string, error) {
+	if v {
+		return "1", nil
+	}
+	return "0", nil
+}
+
+// UnmarshalBoolean unmarshals bool from the SOAP "boolean" type.
+func UnmarshalBoolean(s string) (bool, error) {
+	switch s {
+	case "0", "false", "no":
+		return false, nil
+	case "1", "true", "yes":
+		return true, nil
+	}
+	return false, fmt.Errorf("soap boolean: %q is not a valid boolean value", s)
+}
+
+// MarshalBinBase64 marshals []byte to SOAP "bin.base64" type.
+func MarshalBinBase64(v []byte) (string, error) {
+	return base64.StdEncoding.EncodeToString(v), nil
+}
+
+// UnmarshalBinBase64 unmarshals []byte from the SOAP "bin.base64" type.
+func UnmarshalBinBase64(s string) ([]byte, error) {
+	return base64.StdEncoding.DecodeString(s)
+}
+
+// MarshalBinHex marshals []byte to SOAP "bin.hex" type.
+func MarshalBinHex(v []byte) (string, error) {
+	return hex.EncodeToString(v), nil
+}
+
+// UnmarshalBinHex unmarshals []byte from the SOAP "bin.hex" type.
+func UnmarshalBinHex(s string) ([]byte, error) {
+	return hex.DecodeString(s)
+}
+
+// MarshalURI marshals *url.URL to SOAP "uri" type.
+func MarshalURI(v *url.URL) (string, error) {
+	return v.String(), nil
+}
+
+// UnmarshalURI unmarshals *url.URL from the SOAP "uri" type.
+func UnmarshalURI(s string) (*url.URL, error) {
+	return url.Parse(s)
+}
--- a/vendor/github.com/tailscale/goupnp/ssdp/registry.go
+++ b/vendor/github.com/tailscale/goupnp/ssdp/registry.go
@@ -0,0 +1,312 @@
+package ssdp
+
+import (
+	"fmt"
+	"log"
+	"net/http"
+	"net/url"
+	"regexp"
+	"strconv"
+	"sync"
+	"time"
+
+	"github.com/tailscale/goupnp/httpu"
+)
+
+const (
+	maxExpiryTimeSeconds = 24 * 60 * 60
+)
+
+var (
+	maxAgeRx = regexp.MustCompile("max-age= *([0-9]+)")
+)
+
+const (
+	EventAlive = EventType(iota)
+	EventUpdate
+	EventByeBye
+)
+
+type EventType int8
+
+func (et EventType) String() string {
+	switch et {
+	case EventAlive:
+		return "EventAlive"
+	case EventUpdate:
+		return "EventUpdate"
+	case EventByeBye:
+		return "EventByeBye"
+	default:
+		return fmt.Sprintf("EventUnknown(%d)", int8(et))
+	}
+}
+
+type Update struct {
+	// The USN of the service.
+	USN string
+	// What happened.
+	EventType EventType
+	// The entry, which is nil if the service was not known and
+	// EventType==EventByeBye. The contents of this must not be modified as it is
+	// shared with the registry and other listeners. Once created, the Registry
+	// does not modify the Entry value - any updates are replaced with a new
+	// Entry value.
+	Entry *Entry
+}
+
+type Entry struct {
+	// The address that the entry data was actually received from.
+	RemoteAddr string
+	// Unique Service Name. Identifies a unique instance of a device or service.
+	USN string
+	// Notfication Type. The type of device or service being announced.
+	NT string
+	// Server's self-identifying string.
+	Server string
+	Host   string
+	// Location of the UPnP root device description.
+	Location url.URL
+
+	// Despite BOOTID,CONFIGID being required fields, apparently they are not
+	// always set by devices. Set to -1 if not present.
+
+	BootID   int32
+	ConfigID int32
+
+	SearchPort uint16
+
+	// When the last update was received for this entry identified by this USN.
+	LastUpdate time.Time
+	// When the last update's cached values are advised to expire.
+	CacheExpiry time.Time
+}
+
+func newEntryFromRequest(r *http.Request) (*Entry, error) {
+	now := time.Now()
+	expiryDuration, err := parseCacheControlMaxAge(r.Header.Get("CACHE-CONTROL"))
+	if err != nil {
+		return nil, fmt.Errorf("ssdp: error parsing CACHE-CONTROL max age: %v", err)
+	}
+
+	loc, err := url.Parse(r.Header.Get("LOCATION"))
+	if err != nil {
+		return nil, fmt.Errorf("ssdp: error parsing entry Location URL: %v", err)
+	}
+
+	bootID, err := parseUpnpIntHeader(r.Header, "BOOTID.UPNP.ORG", -1)
+	if err != nil {
+		return nil, err
+	}
+	configID, err := parseUpnpIntHeader(r.Header, "CONFIGID.UPNP.ORG", -1)
+	if err != nil {
+		return nil, err
+	}
+	searchPort, err := parseUpnpIntHeader(r.Header, "SEARCHPORT.UPNP.ORG", ssdpSearchPort)
+	if err != nil {
+		return nil, err
+	}
+
+	if searchPort < 1 || searchPort > 65535 {
+		return nil, fmt.Errorf("ssdp: search port %d is out of range", searchPort)
+	}
+
+	return &Entry{
+		RemoteAddr:  r.RemoteAddr,
+		USN:         r.Header.Get("USN"),
+		NT:          r.Header.Get("NT"),
+		Server:      r.Header.Get("SERVER"),
+		Host:        r.Header.Get("HOST"),
+		Location:    *loc,
+		BootID:      bootID,
+		ConfigID:    configID,
+		SearchPort:  uint16(searchPort),
+		LastUpdate:  now,
+		CacheExpiry: now.Add(expiryDuration),
+	}, nil
+}
+
+func parseCacheControlMaxAge(cc string) (time.Duration, error) {
+	matches := maxAgeRx.FindStringSubmatch(cc)
+	if len(matches) != 2 {
+		return 0, fmt.Errorf("did not find exactly one max-age in cache control header: %q", cc)
+	}
+	expirySeconds, err := strconv.ParseInt(matches[1], 10, 16)
+	if err != nil {
+		return 0, err
+	}
+	if expirySeconds < 1 || expirySeconds > maxExpiryTimeSeconds {
+		return 0, fmt.Errorf("rejecting bad expiry time of %d seconds", expirySeconds)
+	}
+	return time.Duration(expirySeconds) * time.Second, nil
+}
+
+// parseUpnpIntHeader is intended to parse the
+// {BOOT,CONFIGID,SEARCHPORT}.UPNP.ORG header fields. It returns the def if
+// the head is empty or missing.
+func parseUpnpIntHeader(headers http.Header, headerName string, def int32) (int32, error) {
+	s := headers.Get(headerName)
+	if s == "" {
+		return def, nil
+	}
+	v, err := strconv.ParseInt(s, 10, 32)
+	if err != nil {
+		return 0, fmt.Errorf("ssdp: could not parse header %s: %v", headerName, err)
+	}
+	return int32(v), nil
+}
+
+var _ httpu.Handler = new(Registry)
+
+// Registry maintains knowledge of discovered devices and services.
+//
+// NOTE: the interface for this is experimental and may change, or go away
+// entirely.
+type Registry struct {
+	lock  sync.Mutex
+	byUSN map[string]*Entry
+
+	listenersLock sync.RWMutex
+	listeners     map[chan<- Update]struct{}
+}
+
+func NewRegistry() *Registry {
+	return &Registry{
+		byUSN:     make(map[string]*Entry),
+		listeners: make(map[chan<- Update]struct{}),
+	}
+}
+
+// NewServerAndRegistry is a convenience function to create a registry, and an
+// httpu server to pass it messages. Call ListenAndServe on the server for
+// messages to be processed.
+func NewServerAndRegistry() (*httpu.Server, *Registry) {
+	reg := NewRegistry()
+	srv := &httpu.Server{
+		Addr:      ssdpUDP4Addr,
+		Multicast: true,
+		Handler:   reg,
+	}
+	return srv, reg
+}
+
+func (reg *Registry) AddListener(c chan<- Update) {
+	reg.listenersLock.Lock()
+	defer reg.listenersLock.Unlock()
+	reg.listeners[c] = struct{}{}
+}
+
+func (reg *Registry) RemoveListener(c chan<- Update) {
+	reg.listenersLock.Lock()
+	defer reg.listenersLock.Unlock()
+	delete(reg.listeners, c)
+}
+
+func (reg *Registry) sendUpdate(u Update) {
+	reg.listenersLock.RLock()
+	defer reg.listenersLock.RUnlock()
+	for c := range reg.listeners {
+		c <- u
+	}
+}
+
+// GetService returns known service (or device) entries for the given service
+// URN.
+func (reg *Registry) GetService(serviceURN string) []*Entry {
+	// Currently assumes that the map is small, so we do a linear search rather
+	// than indexed to avoid maintaining two maps.
+	var results []*Entry
+	reg.lock.Lock()
+	defer reg.lock.Unlock()
+	for _, entry := range reg.byUSN {
+		if entry.NT == serviceURN {
+			results = append(results, entry)
+		}
+	}
+	return results
+}
+
+// ServeMessage implements httpu.Handler, and uses SSDP NOTIFY requests to
+// maintain the registry of devices and services.
+func (reg *Registry) ServeMessage(r *http.Request) {
+	if r.Method != methodNotify {
+		return
+	}
+
+	nts := r.Header.Get("nts")
+
+	var err error
+	switch nts {
+	case ntsAlive:
+		err = reg.handleNTSAlive(r)
+	case ntsUpdate:
+		err = reg.handleNTSUpdate(r)
+	case ntsByebye:
+		err = reg.handleNTSByebye(r)
+	default:
+		err = fmt.Errorf("unknown NTS value: %q", nts)
+	}
+	if err != nil {
+		log.Printf("goupnp/ssdp: failed to handle %s message from %s: %v", nts, r.RemoteAddr, err)
+	}
+}
+
+func (reg *Registry) handleNTSAlive(r *http.Request) error {
+	entry, err := newEntryFromRequest(r)
+	if err != nil {
+		return err
+	}
+
+	reg.lock.Lock()
+	reg.byUSN[entry.USN] = entry
+	reg.lock.Unlock()
+
+	reg.sendUpdate(Update{
+		USN:       entry.USN,
+		EventType: EventAlive,
+		Entry:     entry,
+	})
+
+	return nil
+}
+
+func (reg *Registry) handleNTSUpdate(r *http.Request) error {
+	entry, err := newEntryFromRequest(r)
+	if err != nil {
+		return err
+	}
+	nextBootID, err := parseUpnpIntHeader(r.Header, "NEXTBOOTID.UPNP.ORG", -1)
+	if err != nil {
+		return err
+	}
+	entry.BootID = nextBootID
+
+	reg.lock.Lock()
+	reg.byUSN[entry.USN] = entry
+	reg.lock.Unlock()
+
+	reg.sendUpdate(Update{
+		USN:       entry.USN,
+		EventType: EventUpdate,
+		Entry:     entry,
+	})
+
+	return nil
+}
+
+func (reg *Registry) handleNTSByebye(r *http.Request) error {
+	usn := r.Header.Get("USN")
+
+	reg.lock.Lock()
+	entry := reg.byUSN[usn]
+	delete(reg.byUSN, usn)
+	reg.lock.Unlock()
+
+	reg.sendUpdate(Update{
+		USN:       usn,
+		EventType: EventByeBye,
+		Entry:     entry,
+	})
+
+	return nil
+}
--- a/vendor/github.com/tailscale/goupnp/ssdp/ssdp.go
+++ b/vendor/github.com/tailscale/goupnp/ssdp/ssdp.go
@@ -0,0 +1,113 @@
+package ssdp
+
+import (
+	"context"
+	"log"
+	"net/http"
+	"net/url"
+	"strconv"
+	"time"
+)
+
+const (
+	ssdpDiscover   = `"ssdp:discover"`
+	ntsAlive       = `ssdp:alive`
+	ntsByebye      = `ssdp:byebye`
+	ntsUpdate      = `ssdp:update`
+	ssdpUDP4Addr   = "239.255.255.250:1900"
+	ssdpSearchPort = 1900
+	methodSearch   = "M-SEARCH"
+	methodNotify   = "NOTIFY"
+
+	// SSDPAll is a value for searchTarget that searches for all devices and services.
+	SSDPAll = "ssdp:all"
+	// UPNPRootDevice is a value for searchTarget that searches for all root devices.
+	UPNPRootDevice = "upnp:rootdevice"
+)
+
+// HTTPUClient is the interface required to perform HTTP-over-UDP requests.
+type HTTPUClient interface {
+	Do(req *http.Request, numSends int) ([]*http.Response, error)
+}
+
+func max(a, b int64) int64 {
+	if a > b {
+		return a
+	}
+	return b
+}
+
+// SSDPRawSearch performs a fairly raw SSDP search request, and returns the
+// unique response(s) that it receives. Each response has the requested
+// searchTarget, a USN, and a valid location. maxWaitSeconds states how long to
+// wait for responses in seconds, and must be a minimum of 1 (the
+// implementation waits an additional 100ms for responses to arrive), 2 is a
+// reasonable value for this. numSends is the number of requests to send - 3 is
+// a reasonable value for this.
+func SSDPRawSearch(
+	ctx context.Context,
+	httpu HTTPUClient,
+	searchTarget string,
+	numSends int,
+) ([]*http.Response, error) {
+	// Must specify at least 1 second according to the spec.
+	var wait int64 = 1
+	// https://openconnectivity.org/upnp-specs/UPnP-arch-DeviceArchitecture-v2.0-20200417.pdf
+	if deadline, ok := ctx.Deadline(); ok {
+		wait = max(wait, int64(time.Until(deadline).Seconds()))
+	}
+
+	header := http.Header{
+		// Putting headers in here avoids them being title-cased.
+		// (The UPnP discovery protocol uses case-sensitive headers)
+		"HOST": []string{ssdpUDP4Addr},
+		"MAN":  []string{ssdpDiscover},
+		"MX":   []string{strconv.FormatInt(wait, 10)},
+		"ST":   []string{searchTarget},
+	}
+
+	req := &http.Request{
+		Method: methodSearch,
+		// TODO: Support both IPv4 and IPv6.
+		Host:   ssdpUDP4Addr,
+		URL:    &url.URL{Opaque: "*"},
+		Header: header,
+	}
+	ctx, cancel := context.WithTimeout(ctx, time.Duration(wait)*time.Second)
+	defer cancel()
+	req = req.WithContext(ctx)
+	allResponses, err := httpu.Do(req, numSends)
+	if err != nil {
+		return nil, err
+	}
+
+	isExactSearch := searchTarget != SSDPAll && searchTarget != UPNPRootDevice
+
+	seenUSNs := make(map[string]bool)
+	var responses []*http.Response
+	for _, response := range allResponses {
+		if response.StatusCode != 200 {
+			log.Printf("ssdp: got response status code %q in search response", response.Status)
+			continue
+		}
+		if st := response.Header.Get("ST"); isExactSearch && st != searchTarget {
+			continue
+		}
+		usn := response.Header.Get("USN")
+		if usn == "" {
+			// Empty/missing USN in search response - using location instead.
+			location, err := response.Location()
+			if err != nil {
+				// No usable location in search response - discard.
+				continue
+			}
+			usn = location.String()
+		}
+		if _, alreadySeen := seenUSNs[usn]; !alreadySeen {
+			seenUSNs[usn] = true
+			responses = append(responses, response)
+		}
+	}
+
+	return responses, nil
+}