Fix frequency calculations

mobile/src/main/java/be/mygod/vpnhotspot/RepeaterService.kt

@@ -45,7 +45,7 @@ class RepeaterService : Service(), CoroutineScope, WifiP2pManager.ChannelListene
 
         private const val KEY_NETWORK_NAME = "service.repeater.networkName"
         private const val KEY_PASSPHRASE = "service.repeater.passphrase"
-        private const val KEY_OPERATING_BAND = "service.repeater.band"
+        private const val KEY_OPERATING_BAND = "service.repeater.band.v2"
         private const val KEY_OPERATING_CHANNEL = "service.repeater.oc"
         private const val KEY_DEVICE_ADDRESS = "service.repeater.mac"
         /**
@@ -80,7 +80,7 @@ class RepeaterService : Service(), CoroutineScope, WifiP2pManager.ChannelListene
         var operatingChannel: Int
             get() {
                 val result = app.pref.getString(KEY_OPERATING_CHANNEL, null)?.toIntOrNull() ?: 0
-                return if (result in 1..165) result else 0
+                return if (result > 0) result else 0
             }
             set(value) = app.pref.edit { putString(KEY_OPERATING_CHANNEL, value.toString()) }
         var deviceAddress: MacAddressCompat?
@@ -359,8 +359,13 @@ class RepeaterService : Service(), CoroutineScope, WifiP2pManager.ChannelListene
                     setNetworkName(PLACEHOLDER_NETWORK_NAME)
                     setPassphrase(passphrase)
                     operatingChannel.let { oc ->
-                        if (oc == 0) setGroupOperatingBand(operatingBand)
+                        if (oc == 0) setGroupOperatingBand(when (operatingBand) {
-                        else setGroupOperatingFrequency(SoftApConfigurationCompat.channelToFrequency(oc))
+                            SoftApConfigurationCompat.BAND_ANY -> WifiP2pConfig.GROUP_OWNER_BAND_AUTO
+                            SoftApConfigurationCompat.BAND_2GHZ -> WifiP2pConfig.GROUP_OWNER_BAND_2GHZ
+                            SoftApConfigurationCompat.BAND_5GHZ -> WifiP2pConfig.GROUP_OWNER_BAND_5GHZ
+                            else -> throw IllegalArgumentException("Unknown band")
+                        })
+                        else setGroupOperatingFrequency(SoftApConfigurationCompat.channelToFrequency(operatingBand, oc))
                     }
                     setDeviceAddress(deviceAddress?.toPlatform())
                 }.build().run {

mobile/src/main/java/be/mygod/vpnhotspot/manage/RepeaterManager.kt

@@ -192,12 +192,7 @@ class RepeaterManager(private val parent: TetheringFragment) : Manager(), Servic
                     ssid = networkName
                     securityType = SoftApConfiguration.SECURITY_TYPE_WPA2_PSK   // is not actually used
                     this.passphrase = passphrase
-                    band = when (RepeaterService.operatingBand) {
+                    band = RepeaterService.operatingBand
-                        WifiP2pConfig.GROUP_OWNER_BAND_AUTO -> SoftApConfigurationCompat.BAND_ANY
-                        WifiP2pConfig.GROUP_OWNER_BAND_2GHZ -> SoftApConfigurationCompat.BAND_2GHZ
-                        WifiP2pConfig.GROUP_OWNER_BAND_5GHZ -> SoftApConfigurationCompat.BAND_5GHZ
-                        else -> throw IllegalArgumentException("Unknown operatingBand")
-                    }
                     channel = RepeaterService.operatingChannel
                     bssid = RepeaterService.deviceAddress
                 } to false
@@ -231,12 +226,7 @@ class RepeaterManager(private val parent: TetheringFragment) : Manager(), Servic
         if (RepeaterService.safeMode) {
             RepeaterService.networkName = config.ssid
             RepeaterService.passphrase = config.passphrase
-            RepeaterService.operatingBand = when (config.band) {
+            RepeaterService.operatingBand = config.band
-                SoftApConfigurationCompat.BAND_ANY -> WifiP2pConfig.GROUP_OWNER_BAND_AUTO
-                SoftApConfigurationCompat.BAND_2GHZ -> WifiP2pConfig.GROUP_OWNER_BAND_2GHZ
-                SoftApConfigurationCompat.BAND_5GHZ -> WifiP2pConfig.GROUP_OWNER_BAND_5GHZ
-                else -> throw IllegalArgumentException("Unknown band")
-            }
         } else holder.config?.let { master ->
             val binder = binder
             if (binder?.group?.networkName != config.ssid || master.psk != config.passphrase ||

mobile/src/main/java/be/mygod/vpnhotspot/net/wifi/SoftApConfigurationCompat.kt

@@ -53,17 +53,35 @@ data class SoftApConfigurationCompat(
         private val qrSanitizer = Regex("([\\\\\":;,])")
 
         /**
-         * The frequency which AP resides on (MHz). Resides in range [2412, 5815].
+         * Based on:
+         * https://elixir.bootlin.com/linux/v5.7.6/source/net/wireless/util.c#L75
+         * TODO [com.android.server.wifi.util.ApConfigUtil]
          */
-        fun channelToFrequency(channel: Int) = when (channel) {
+        fun channelToFrequency(band: Int, chan: Int) = when (band) {
-            in 1..14 -> 2407 + 5 * channel
+            BAND_2GHZ -> when (chan) {
-            in 15..165 -> 5000 + 5 * channel
+                14 -> 2484
-            else -> throw IllegalArgumentException("Invalid channel $channel")
+                in 1 until 14 -> 2407 + chan * 5
+                else -> throw IllegalArgumentException("Invalid 2GHz channel $chan")
+            }
+            BAND_5GHZ -> when (chan) {
+                in 182..196 -> 4000 + chan * 5
+                in 1..Int.MAX_VALUE -> 5000 + chan * 5
+                else -> throw IllegalArgumentException("Invalid 5GHz channel $chan")
+            }
+            BAND_6GHZ -> if (chan in 1..253) {
+                5940 + chan * 5
+            } else throw IllegalArgumentException("Invalid 6GHz channel $chan")
+            // BAND_60GHZ -> if (chan in 1 until 7) 56160 + chan * 2160
+            else -> throw IllegalArgumentException("Invalid band $band")
         }
-        fun frequencyToChannel(frequency: Int) = when (frequency % 5) {
+        fun frequencyToChannel(freq: Int) = when (freq) {
-            2 -> ((frequency - 2407) / 5).also { check(it in 1..14) { "Invalid 2.4 GHz frequency $frequency" } }
+            2484 -> 14
-            0 -> ((frequency - 5000) / 5).also { check(it in 15..165) { "Invalid 5 GHz frequency $frequency" } }
+            in Int.MIN_VALUE until 2484 -> (freq - 2407) / 5
-            else -> throw IllegalArgumentException("Invalid frequency $frequency")
+            in 4910..4980 -> (freq - 4000) / 5
+            in Int.MIN_VALUE until 5945 -> (freq - 5000) / 5
+            in Int.MIN_VALUE..45000 -> (freq - 5940) / 5
+            in 58320..70200 -> (freq - 56160) / 2160
+            else -> throw IllegalArgumentException("Invalid frequency $freq")
         }
 
         /**

mobile/src/main/java/be/mygod/vpnhotspot/net/wifi/WifiApDialogFragment.kt

@@ -41,7 +41,24 @@ class WifiApDialogFragment : AlertDialogFragment<WifiApDialogFragment.Arg, WifiA
         Toolbar.OnMenuItemClickListener {
     companion object {
         private const val BASE64_FLAGS = Base64.NO_PADDING or Base64.NO_WRAP
-        private val channels by lazy { (1..165).map { BandOption.Channel(it) } }
+        private val channels by lazy {
+            val list = ArrayList<BandOption.Channel>()
+            for (chan in 1..14) list.add(BandOption.Channel(SoftApConfigurationCompat.BAND_2GHZ, chan))
+            for (chan in 1..196) list.add(BandOption.Channel(SoftApConfigurationCompat.BAND_5GHZ, chan))
+            if (Build.VERSION.SDK_INT >= 30) {
+                for (chan in 1..253) list.add(BandOption.Channel(SoftApConfigurationCompat.BAND_6GHZ, chan))
+            }
+            list
+        }
+        /**
+         * Source: https://android.googlesource.com/platform/frameworks/opt/net/wifi/+/c2fc6a1/service/java/com/android/server/wifi/p2p/SupplicantP2pIfaceHal.java#1396
+         */
+        private val p2pChannels by lazy {
+            (1..165).map {
+                val band = if (it <= 14) SoftApConfigurationCompat.BAND_2GHZ else SoftApConfigurationCompat.BAND_5GHZ
+                BandOption.Channel(band, it)
+            }
+        }
     }
 
     @Parcelize
@@ -73,8 +90,8 @@ class WifiApDialogFragment : AlertDialogFragment<WifiApDialogFragment.Arg, WifiA
             override val band get() = SoftApConfigurationCompat.BAND_6GHZ
             override fun toString() = app.getString(R.string.wifi_ap_choose_6G)
         }
-        class Channel(override val channel: Int) : BandOption() {
+        class Channel(override val band: Int, override val channel: Int) : BandOption() {
-            override fun toString() = "${SoftApConfigurationCompat.channelToFrequency(channel)} MHz ($channel)"
+            override fun toString() = "${SoftApConfigurationCompat.channelToFrequency(band, channel)} MHz ($channel)"
         }
     }
 
@@ -132,13 +149,14 @@ class WifiApDialogFragment : AlertDialogFragment<WifiApDialogFragment.Arg, WifiA
                         add(BandOption.Band2GHz)
                         add(BandOption.Band5GHz)
                     }
+                    addAll(p2pChannels)
                 } else {
                     if (Build.VERSION.SDK_INT >= 28) add(BandOption.BandAny)
                     add(BandOption.Band2GHz)
                     add(BandOption.Band5GHz)
                     if (Build.VERSION.SDK_INT >= 30) add(BandOption.Band6GHz)
+                    addAll(channels)
                 }
-                addAll(channels)
             }
             adapter = ArrayAdapter(activity, android.R.layout.simple_spinner_item, 0, bandOptions).apply {
                 setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item)