GM cars also get their Bluetooth and Wi-Fi projection channels opened

The 2021 Bolt still hangs up about 20 seconds in with pings answered and GM's channel open.
These are the two channels it offers that Gearslip had never opened. What arrives on them is
logged. Without an address typed in Settings, no PairingRequest is sent.

gearslip/src/main/java/app/seb3thehacker/gearslip/GearslipRunner.kt

@@ -107,6 +107,8 @@ class GearslipRunner(
     @Volatile private var audioLink: AudioLink? = null
     @Volatile private var guidanceLink: AudioLink? = null
     @Volatile private var vendorChannelId = -1
+    /** The car's Wi-Fi projection channel, opened in GM cars only (see [startVendorChannel]); -1 when closed. */
+    @Volatile private var wifiChannelId = -1
     private var audioMessagesSeen = 0
     private var touchWidth = 0
     private var touchHeight = 0
@@ -260,6 +262,8 @@ class GearslipRunner(
                 CarBluetooth.onMessage(messageId, body)
             } else if (frame.channel == vendorChannelId) {
                 onVendorMessage(messageId, body)
+            } else if (frame.channel == wifiChannelId) {
+                onWifiProjectionMessage(messageId, body)
             } else if (frame.channel == CarMic.current?.channelId) {
                 CarMic.current?.onMessage(messageId, body)
             } else if (frame.channel == audioLink?.channelId) {
@@ -726,6 +730,23 @@ class GearslipRunner(
         vendorChannelId = gm.serviceId
         log.i("-> ChannelOpenRequest on GM's channel ${gm.serviceId}")
         openChannel(gm.serviceId)
+        // Opening GM's channel and pinging the car didn't stop the Bolt hanging up, so a GM car
+        // also gets the two channels Gearslip had never opened: Bluetooth and Wi-Fi projection.
+        // Only what arrives on them is logged, by message id and size, until one turns out to matter.
+        CarBluetooth.announce("a GM car, issue #18")
+        ServiceDiscovery.findWifiProjectionService(serviceDiscoveryResponse)?.let { channel ->
+            wifiChannelId = channel
+            log.i("-> ChannelOpenRequest on the Wi-Fi projection channel $channel (a GM car, issue #18)")
+            openChannel(channel)
+        }
+    }
+
+    private fun onWifiProjectionMessage(messageId: Int, body: ByteArray) {
+        if (messageId == MSG_CHANNEL_OPEN_RESPONSE) {
+            log.i("<- Wi-Fi projection channel open: status=${Protobuf.readInt32Field(body, 1) ?: 0}")
+        } else {
+            log.i("<- Wi-Fi projection message id=$messageId (${body.size} bytes)")
+        }
     }
 
     private fun onVendorMessage(messageId: Int, body: ByteArray) {

gearslip/src/main/java/app/seb3thehacker/gearslip/ServiceDiscovery.kt

@@ -200,6 +200,13 @@ object ServiceDiscovery {
             VendorService(id, name)
         }
 
+    /** The channel of the car's Wi-Fi projection service (Service field 14), or null. */
+    fun findWifiProjectionService(response: ByteArray): Int? =
+        Wire.allBytes(Wire.fields(response), 1).firstNotNullOfOrNull { channel ->
+            val service = Wire.fields(channel)
+            if (Wire.bytes(service, 14) == null) null else Wire.varint(service, 1)?.toInt()
+        }
+
     fun findBluetoothService(response: ByteArray): BluetoothService? {
         for (channel in Wire.allBytes(Wire.fields(response), 1)) {
             val service = Wire.fields(channel)

gearslip/src/main/java/app/seb3thehacker/gearslip/car/CarBluetooth.kt

@@ -105,6 +105,20 @@ object CarBluetooth {
         }
     }
 
+    /**
+     * Opens the car's Bluetooth channel though there's no pairing to do, as a real phone does on
+     * every connection. Issue #18: a 2021 Bolt hangs up about 20 seconds in, and this is one of
+     * the two channels it offers that Gearslip never opened. Without an address the driver typed,
+     * it only opens the channel: a made-up address could set the car pairing with the wrong phone.
+     */
+    fun announce(why: String) {
+        val c = car ?: return
+        if (pairing || announcing) return
+        announcing = true
+        log.i("-> ChannelOpenRequest on channel ${c.service.serviceId} ($why)")
+        c.open()
+    }
+
     fun onCarDisconnected() {
         car = null
         pairing = false
@@ -157,6 +171,10 @@ object CarBluetooth {
                     else main.post { startBond("the car wouldn't open its Bluetooth channel") }
                     return
                 }
+                if (announcing && typedAddress() == null) {
+                    log.i("Bluetooth channel open; no address typed in Settings, so no PairingRequest")
+                    return
+                }
                 val method = c.service.pairingMethods.firstOrNull { it == METHOD_NUMERIC_COMPARISON }
                     ?: c.service.pairingMethods.firstOrNull() ?: METHOD_NUMERIC_COMPARISON
                 c.send(