Update dependencies

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
+}