Add HomeKit QR code to WebUI #1138 by @mnakada

internal/homekit/homekit.go

@@ -65,10 +65,12 @@ func Init() {
 
 		deviceID := calcDeviceID(conf.DeviceID, id) // random MAC-address
 		name := calcName(conf.Name, deviceID)
+		setupID := calcSetupID(id)
 
 		srv := &server{
 			stream:   id,
 			pairings: conf.Pairings,
+			setupID:  setupID,
 		}
 
 		srv.hap = &hap.Server{
@@ -90,7 +92,7 @@ func Init() {
 				hap.TXTStateNumber:  "1",
 				hap.TXTStatusFlags:  hap.StatusNotPaired,
 				hap.TXTCategory:     calcCategoryID(conf.CategoryID),
-				hap.TXTSetupHash:    srv.hap.SetupHash(),
+				hap.TXTSetupHash:    hap.SetupHash(setupID, deviceID),
 			},
 		}
 		entries = append(entries, srv.mdns)

internal/homekit/server.go

@@ -40,20 +40,29 @@ type server struct {
 	accessory *hap.Accessory // HAP accessory
 	consumer  *homekit.Consumer
 	proxyURL  string
+	setupID   string
 	stream    string // stream name from YAML
 }
 
 func (s *server) MarshalJSON() ([]byte, error) {
 	v := struct {
-		Name     string `json:"name"`
-		DeviceID string `json:"device_id"`
-		Paired   int    `json:"paired"`
-		Conns    []any  `json:"connections"`
+		Name       string `json:"name"`
+		DeviceID   string `json:"device_id"`
+		Paired     int    `json:"paired,omitempty"`
+		CategoryID string `json:"category_id,omitempty"`
+		SetupCode  string `json:"setup_code,omitempty"`
+		SetupID    string `json:"setup_id,omitempty"`
+		Conns      []any  `json:"connections,omitempty"`
 	}{
-		Name:     s.mdns.Name,
-		DeviceID: s.mdns.Info[hap.TXTDeviceID],
-		Paired:   len(s.pairings),
-		Conns:    s.conns,
+		Name:       s.mdns.Name,
+		DeviceID:   s.mdns.Info[hap.TXTDeviceID],
+		CategoryID: s.mdns.Info[hap.TXTCategory],
+		Paired:     len(s.pairings),
+		Conns:      s.conns,
+	}
+	if v.Paired == 0 {
+		v.SetupCode = s.hap.Pin
+		v.SetupID = s.setupID
 	}
 	return json.Marshal(v)
 }
@@ -377,6 +386,11 @@ func calcDevicePrivate(private, seed string) []byte {
 	return ed25519.NewKeyFromSeed(b[:ed25519.SeedSize])
 }
 
+func calcSetupID(seed string) string {
+	b := sha512.Sum512([]byte(seed))
+	return fmt.Sprintf("%02X%02X", b[44], b[46])
+}
+
 func calcCategoryID(categoryID string) string {
 	switch categoryID {
 	case "bridge":

pkg/hap/helpers.go

@@ -3,6 +3,8 @@ package hap
 import (
 	"crypto/ed25519"
 	"crypto/rand"
+	"crypto/sha512"
+	"encoding/base64"
 	"encoding/hex"
 	"errors"
 	"fmt"
@@ -99,6 +101,12 @@ func GenerateUUID() string {
 	return s[:8] + "-" + s[8:12] + "-" + s[12:16] + "-" + s[16:20] + "-" + s[20:]
 }
 
+func SetupHash(setupID, deviceID string) string {
+	// should be setup_id (random 4 alphanum) + device_id (mac address)
+	b := sha512.Sum512([]byte(setupID + deviceID))
+	return base64.StdEncoding.EncodeToString(b[:4])
+}
+
 func Append(items ...any) (b []byte) {
 	for _, item := range items {
 		switch v := item.(type) {

pkg/hap/server.go

@@ -3,7 +3,6 @@ package hap
 import (
 	"bufio"
 	"crypto/sha512"
-	"encoding/base64"
 	"errors"
 	"fmt"
 	"net/http"
@@ -36,13 +35,6 @@ func (s *Server) ServerPublic() []byte {
 //	return StatusPaired
 //}
 
-func (s *Server) SetupHash() string {
-	// should be setup_id (random 4 alphanum) + device_id (mac address)
-	// but device_id is random, so OK
-	b := sha512.Sum512([]byte(s.DeviceID))
-	return base64.StdEncoding.EncodeToString(b[:4])
-}
-
 func (s *Server) PairSetup(req *http.Request, rw *bufio.ReadWriter) (id string, publicKey []byte, err error) {
 	// STEP 1. Request from iPhone
 	var plainM1 struct {

pkg/hap/setup/setup.go

@@ -0,0 +1,32 @@
+package setup
+
+import (
+	"strconv"
+	"strings"
+)
+
+const (
+	FlagNFC = 1
+	FlagIP  = 2
+	FlagBLE = 4
+	FlagWAC = 8 // Wireless Accessory Configuration (WAC)/Apples MFi
+)
+
+func GenerateSetupURI(category, pin, setupID string) string {
+	c, _ := strconv.Atoi(category)
+	p, _ := strconv.Atoi(strings.ReplaceAll(pin, "-", ""))
+	payload := int64(c&0xFF)<<31 | int64(FlagIP&0xF)<<27 | int64(p&0x7FFFFFF)
+	return "X-HM://" + FormatInt36(payload, 9) + setupID
+}
+
+// FormatInt36 equal to strings.ToUpper(fmt.Sprintf("%0"+strconv.Itoa(n)+"s", strconv.FormatInt(value, 36)))
+func FormatInt36(value int64, n int) string {
+	b := make([]byte, n)
+	for i := n - 1; 0 <= i; i-- {
+		b[i] = digits[value%36]
+		value /= 36
+	}
+	return string(b)
+}
+
+const digits = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"

pkg/hap/setup/setup_test.go

@@ -0,0 +1,18 @@
+package setup
+
+import (
+	"fmt"
+	"strconv"
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestFormatAlphaNum(t *testing.T) {
+	value := int64(999)
+	n := 5
+	s1 := strings.ToUpper(fmt.Sprintf("%0"+strconv.Itoa(n)+"s", strconv.FormatInt(value, 36)))
+	s2 := FormatInt36(value, n)
+	require.Equal(t, s1, s2)
+}

www/links.html

@@ -71,6 +71,42 @@
         });
     </script>
 
+    <div id="homekit" style="display: none">
+        <h2>HomeKit server</h2>
+    </div>
+    <script>
+        fetch(`api/homekit?id=${src}`, {cache: 'no-cache'}).then(async (r) => {
+            if (!r.ok) return;
+
+            const div = document.querySelector('#homekit');
+            div.innerHTML += `<div><a href="${r.url}">info.json</a> page with active connections</div>`;
+            div.style = '';
+
+            /** @type {{name: string, category_id: string, setup_code: string, setup_id: string, setup_uri: string}} */
+            const data = await r.json();
+            if (data.setup_code === undefined) return;
+
+            const script = document.createElement('script');
+            script.src = 'https://cdnjs.cloudflare.com/ajax/libs/qrcodejs/1.0.0/qrcode.min.js';
+            script.async = true;
+            script.onload = () => {
+                /* global BigInt */
+                const categoryID = BigInt(data.category_id);
+                const pin = BigInt(data.setup_code.replaceAll('-', ''));
+                const payload = categoryID << BigInt(31) | BigInt(2 << 27) | pin;
+                const setupURI = `X-HM://${payload.toString(36).toUpperCase().padStart(9, '0')}${data.setup_id}`;
+
+                div.innerHTML += `<pre>Setup Name: ${data.name}
+Setup Code: ${data.setup_code}</pre>
+<div id="homekit-qrcode"></div>`;
+
+                /* global QRCode */
+                new QRCode('homekit-qrcode', {text: setupURI, width: 128, height: 128});
+            };
+            document.head.appendChild(script);
+        });
+    </script>
+
     <div>
         <h2>Play audio</h2>
         <label><input type="radio" name="play" value="file" checked>