mirror of
https://github.com/meshtastic/Meshtastic-Android.git
synced 2026-04-20 22:23:37 +00:00
89 lines
No EOL
3.6 KiB
Kotlin
89 lines
No EOL
3.6 KiB
Kotlin
package com.geeksville.mesh.model
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import com.geeksville.mesh.ChannelProtos
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import com.google.protobuf.ByteString
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/** Utility function to make it easy to declare byte arrays - FIXME move someplace better */
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fun byteArrayOfInts(vararg ints: Int) = ByteArray(ints.size) { pos -> ints[pos].toByte() }
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data class Channel(val settings: ChannelProtos.ChannelSettings) {
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companion object {
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// These bytes must match the well known and not secret bytes used the default channel AES128 key device code
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val channelDefaultKey = byteArrayOfInts(
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0xd4, 0xf1, 0xbb, 0x3a, 0x20, 0x29, 0x07, 0x59,
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0xf0, 0xbc, 0xff, 0xab, 0xcf, 0x4e, 0x69, 0x01
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)
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private val cleartextPSK = ByteString.EMPTY
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private val defaultPSK =
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byteArrayOfInts(1) // a shortstring code to indicate we need our default PSK
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// TH=he unsecured channel that devices ship with
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val default = Channel(
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ChannelProtos.ChannelSettings.newBuilder()
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.setModemConfig(ChannelProtos.ChannelSettings.ModemConfig.LongFast)
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.setPsk(ByteString.copyFrom(defaultPSK))
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.build()
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)
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}
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/// Return the name of our channel as a human readable string. If empty string, assume "Default" per mesh.proto spec
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val name: String
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get() = if (settings.name.isEmpty()) {
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// We have a new style 'empty' channel name. Use the same logic from the device to convert that to a human readable name
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if (settings.bandwidth != 0)
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"Unset"
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else when (settings.modemConfig) {
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ChannelProtos.ChannelSettings.ModemConfig.ShortFast -> "ShortFast"
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ChannelProtos.ChannelSettings.ModemConfig.ShortSlow -> "ShortSlow"
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ChannelProtos.ChannelSettings.ModemConfig.MidFast -> "MidFast"
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ChannelProtos.ChannelSettings.ModemConfig.MidSlow -> "MidSlow"
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ChannelProtos.ChannelSettings.ModemConfig.LongFast -> "LongFast"
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ChannelProtos.ChannelSettings.ModemConfig.LongSlow -> "LongSlow"
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ChannelProtos.ChannelSettings.ModemConfig.VLongSlow -> "VLongSlow"
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else -> "Invalid"
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}
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} else
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settings.name
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val modemConfig: ChannelProtos.ChannelSettings.ModemConfig get() = settings.modemConfig
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val psk
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get() = if (settings.psk.size() != 1)
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settings.psk // A standard PSK
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else {
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// One of our special 1 byte PSKs, see mesh.proto for docs.
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val pskIndex = settings.psk.byteAt(0).toInt()
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if (pskIndex == 0)
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cleartextPSK
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else {
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// Treat an index of 1 as the old channelDefaultKey and work up from there
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val bytes = channelDefaultKey.clone()
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bytes[bytes.size - 1] = (0xff and (bytes[bytes.size - 1] + pskIndex - 1)).toByte()
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ByteString.copyFrom(bytes)
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}
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}
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/**
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* Return a name that is formatted as #channename-suffix
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*
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* Where suffix indicates the hash of the PSK
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*/
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val humanName: String
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get() {
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// start with the PSK then xor in the name
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val pskCode = xorHash(psk.toByteArray())
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val nameCode = xorHash(name.toByteArray())
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val suffix = 'A' + ((pskCode xor nameCode) % 26)
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return "#${name}-${suffix}"
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}
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override fun equals(o: Any?): Boolean = (o is Channel)
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&& psk.toByteArray() contentEquals o.psk.toByteArray()
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&& name == o.name
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}
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fun xorHash(b: ByteArray) = b.fold(0, { acc, x -> acc xor (x.toInt() and 0xff) }) |