mirror of
https://github.com/permissionlesstech/bitchat-android.git
synced 2026-07-25 06:25:21 +00:00
Migrate private media without silent downgrades
This commit is contained in:
jack
@@ -51,97 +51,123 @@ class FragmentManager {
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* Create fragments from a large packet - 100% iOS Compatible
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* Matches iOS sendFragmentedPacket() implementation exactly
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*/
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fun createFragments(packet: BitchatPacket): List<BitchatPacket> {
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/** Generic/public packets retain the full UInt16 fragment-count range. */
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fun createFragments(packet: BitchatPacket): List<BitchatPacket> =
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createFragments(packet, 0xFFFF)
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/**
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* Create a fragment plan with a caller-selected bound. Private media uses
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* 256 for cross-platform admission; generic/public traffic retains the
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* UInt16 wire limit.
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*/
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fun createFragments(packet: BitchatPacket, maxFragments: Int): List<BitchatPacket> {
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try {
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if (maxFragments !in 1..0xFFFF) {
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Log.w(TAG, "Rejecting invalid outbound fragment limit: $maxFragments")
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return emptyList()
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}
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Log.d(TAG, "🔀 Creating fragments for packet type ${packet.type}, payload: ${packet.payload.size} bytes")
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val encoded = packet.toBinaryData()
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val encoded = packet.toBinaryData()
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if (encoded == null) {
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Log.e(TAG, "❌ Failed to encode packet to binary data")
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return emptyList()
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}
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Log.d(TAG, "📦 Encoded to ${encoded.size} bytes")
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// Fragment the unpadded frame; each fragment will be encoded (and padded) independently - iOS fix
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val fullData = try {
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// Fragment the unpadded frame; each fragment will be encoded (and padded) independently - iOS fix
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val fullData = try {
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MessagePadding.unpad(encoded)
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} catch (e: Exception) {
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Log.e(TAG, "❌ Failed to unpad data: ${e.message}", e)
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return emptyList()
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}
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Log.d(TAG, "📏 Unpadded to ${fullData.size} bytes")
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// iOS logic: if data.count > 512 && packet.type != MessageType.fragment.rawValue
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if (fullData.size <= FRAGMENT_SIZE_THRESHOLD) {
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return listOf(packet) // No fragmentation needed
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}
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val fragments = mutableListOf<BitchatPacket>()
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// iOS: let fragmentID = Data((0..<8).map { _ in UInt8.random(in: 0...255) })
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val fragmentID = FragmentPayload.generateFragmentID()
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// iOS: stride(from: 0, to: fullData.count, by: maxFragmentSize)
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// Calculate dynamic fragment size to fit in MTU (512)
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// Packet = Header + Sender + Recipient + Route + FragmentHeader + Payload + PaddingBuffer
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val hasRoute = packet.route != null
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val version = if (hasRoute) 2 else 1
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val headerSize = if (version == 2) 15 else 13
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val senderSize = 8
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val recipientSize = if (packet.recipientID != null) 8 else 0
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// Route: 1 byte count + 8 bytes per hop
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val routeSize = if (hasRoute) (1 + (packet.route?.size ?: 0) * 8) else 0
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val fragmentHeaderSize = 13 // FragmentPayload header
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val paddingBuffer = 16 // MessagePadding.optimalBlockSize adds 16 bytes overhead
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// 512 - Overhead
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val packetOverhead = headerSize + senderSize + recipientSize + routeSize + fragmentHeaderSize + paddingBuffer
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val maxDataSize = (512 - packetOverhead).coerceAtMost(MAX_FRAGMENT_SIZE)
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if (maxDataSize <= 0) {
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Log.e(TAG, "❌ Calculated maxDataSize is non-positive ($maxDataSize). Route too large?")
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return emptyList()
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}
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// iOS logic: if data.count > 512 && packet.type != MessageType.fragment.rawValue
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if (fullData.size <= FRAGMENT_SIZE_THRESHOLD) {
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return listOf(packet) // No fragmentation needed
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}
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Log.d(TAG, "📏 Dynamic fragment size: $maxDataSize (MAX: $MAX_FRAGMENT_SIZE, Overhead: $packetOverhead)")
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val fragments = mutableListOf<BitchatPacket>()
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val fragmentChunks = stride(0, fullData.size, maxDataSize) { offset ->
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val endOffset = minOf(offset + maxDataSize, fullData.size)
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fullData.sliceArray(offset..<endOffset)
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}
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Log.d(TAG, "Creating ${fragmentChunks.size} fragments for ${fullData.size} byte packet (iOS compatible)")
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// iOS: for (index, fragment) in fragments.enumerated()
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for (index in fragmentChunks.indices) {
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val fragmentData = fragmentChunks[index]
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// Create iOS-compatible fragment payload
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val fragmentPayload = FragmentPayload(
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fragmentID = fragmentID,
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index = index,
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total = fragmentChunks.size,
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originalType = packet.type,
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data = fragmentData
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)
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// iOS: MessageType.fragment.rawValue (single fragment type)
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// Fix: Fragments must inherit source route and use v2 if routed
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val fragmentPacket = BitchatPacket(
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version = if (packet.route != null) 2u else 1u,
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type = MessageType.FRAGMENT.value,
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ttl = packet.ttl,
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senderID = packet.senderID,
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recipientID = packet.recipientID,
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timestamp = packet.timestamp,
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payload = fragmentPayload.encode(),
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route = packet.route,
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signature = null // iOS: signature: nil
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)
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fragments.add(fragmentPacket)
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}
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Log.d(TAG, "✅ Created ${fragments.size} fragments successfully")
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// iOS: let fragmentID = Data((0..<8).map { _ in UInt8.random(in: 0...255) })
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val fragmentID = FragmentPayload.generateFragmentID()
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// iOS: stride(from: 0, to: fullData.count, by: maxFragmentSize)
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// Calculate dynamic fragment size to fit in MTU (512)
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// Packet = Header + Sender + Recipient + Route + FragmentHeader + Payload + PaddingBuffer
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val hasRoute = packet.route != null
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val version = if (hasRoute) 2 else 1
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val headerSize = if (version == 2) 15 else 13
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val senderSize = 8
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val recipientSize = if (packet.recipientID != null) 8 else 0
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// Route: 1 byte count + 8 bytes per hop
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val routeSize = if (hasRoute) (1 + (packet.route?.size ?: 0) * 8) else 0
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val fragmentHeaderSize = 13 // FragmentPayload header
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val paddingBuffer = 16 // MessagePadding.optimalBlockSize adds 16 bytes overhead
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// 512 - Overhead
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val packetOverhead = headerSize + senderSize + recipientSize + routeSize + fragmentHeaderSize + paddingBuffer
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val maxDataSize = (512 - packetOverhead).coerceAtMost(MAX_FRAGMENT_SIZE)
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if (maxDataSize <= 0) {
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Log.e(TAG, "❌ Calculated maxDataSize is non-positive ($maxDataSize). Route too large?")
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return emptyList()
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}
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Log.d(TAG, "📏 Dynamic fragment size: $maxDataSize (MAX: $MAX_FRAGMENT_SIZE, Overhead: $packetOverhead)")
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val requiredFragments = (
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(fullData.size.toLong() + maxDataSize.toLong() - 1L) / maxDataSize.toLong()
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).toInt()
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if (requiredFragments > maxFragments) {
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Log.w(
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TAG,
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"Rejecting outbound packet requiring $requiredFragments fragments " +
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"(caller cap: $maxFragments)"
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)
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return emptyList()
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}
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// Do not allocate chunk copies until the plan passes the hard bound.
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val fragmentChunks = stride(0, fullData.size, maxDataSize) { offset ->
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val endOffset = minOf(offset + maxDataSize, fullData.size)
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fullData.sliceArray(offset..<endOffset)
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}
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Log.d(TAG, "Creating ${fragmentChunks.size} fragments for ${fullData.size} byte packet (iOS compatible)")
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// iOS: for (index, fragment) in fragments.enumerated()
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for (index in fragmentChunks.indices) {
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val fragmentData = fragmentChunks[index]
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// Create iOS-compatible fragment payload
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val fragmentPayload = FragmentPayload(
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fragmentID = fragmentID,
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index = index,
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total = fragmentChunks.size,
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originalType = packet.type,
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data = fragmentData
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)
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// iOS: MessageType.fragment.rawValue (single fragment type)
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// Fix: Fragments must inherit source route and use v2 if routed
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val fragmentPacket = BitchatPacket(
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version = if (packet.route != null) 2u else 1u,
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type = MessageType.FRAGMENT.value,
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ttl = packet.ttl,
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senderID = packet.senderID,
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recipientID = packet.recipientID,
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timestamp = packet.timestamp,
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payload = fragmentPayload.encode(),
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route = packet.route,
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signature = null // iOS: signature: nil
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)
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fragments.add(fragmentPacket)
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}
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Log.d(TAG, "✅ Created ${fragments.size} fragments successfully")
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return fragments
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} catch (e: Exception) {
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Log.e(TAG, "❌ Fragment creation failed: ${e.message}", e)
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