static Smb2ChainedCompressedPacket()
{
var header = new Compression_Transform_Header();
FirstPayloadHeaderOffset = TypeMarshal.GetBlockMemorySize(header.ProtocolId) + TypeMarshal.GetBlockMemorySize(header.OriginalCompressedSegmentSize);
var payloadHeader = new SMB2_COMPRESSION_PAYLOAD_HEADER();
FieldSizeOriginalPayloadSize = TypeMarshal.GetBlockMemorySize(payloadHeader.OriginalPayloadSize);
}
private static Tuple <SMB2_COMPRESSION_PAYLOAD_HEADER, object> ChainedCompressWithCompressionAlgorithm(byte[] data, Smb2CompressionInfo compressionInfo, ref bool isFirst)
{
var compressionAlgorithm = GetPreferredCompressionAlgorithm(compressionInfo);
SMB2_COMPRESSION_PAYLOAD_HEADER payloadHeader;
bool isFirstCopy;
isFirstCopy = isFirst;
var compressedPayloadHeader = SMB2_COMPRESSION_PAYLOAD_HEADER.Create(compressionAlgorithm, 0, (UInt32)data.Length, ref isFirstCopy);
isFirstCopy = isFirst;
var uncompressedPayloadHeader = SMB2_COMPRESSION_PAYLOAD_HEADER.Create(CompressionAlgorithm.NONE, (UInt32)data.Length, 0, ref isFirstCopy);
isFirst = isFirstCopy;
byte[] payloadData;
if (compressionAlgorithm != CompressionAlgorithm.NONE)
{
var compressor = GetCompressor(compressionAlgorithm);
var compressedData = compressor.Compress(data);
int compressedDataLength = TypeMarshal.ToBytes(compressedPayloadHeader).Length + compressedData.Length;
int uncompressedDataLength = TypeMarshal.ToBytes(uncompressedPayloadHeader).Length + data.Length;
if (compressedDataLength < uncompressedDataLength)
{
compressedPayloadHeader.Length = (UInt32)(compressedData.Length + FieldSizeOriginalPayloadSize);
payloadHeader = compressedPayloadHeader;
payloadData = compressedData;
}
else
{
payloadHeader = uncompressedPayloadHeader;
payloadData = data;
}
}
else
{
payloadHeader = uncompressedPayloadHeader;
payloadData = data;
}
return(new Tuple <SMB2_COMPRESSION_PAYLOAD_HEADER, object>(payloadHeader, payloadData));
}
static Smb2Compression()
{
compressorInstances = new Dictionary <CompressionAlgorithm, XcaCompressor>
{
[CompressionAlgorithm.LZNT1] = new LZNT1Compressor(),
[CompressionAlgorithm.LZ77] = new PlainLZ77Compressor(),
[CompressionAlgorithm.LZ77Huffman] = new LZ77HuffmanCompressor()
};
decompressorInstances = new Dictionary <CompressionAlgorithm, XcaDecompressor>
{
[CompressionAlgorithm.LZNT1] = new LZNT1Decompressor(),
[CompressionAlgorithm.LZ77] = new PlainLZ77Decompressor(),
[CompressionAlgorithm.LZ77Huffman] = new LZ77HuffmanDecompressor()
};
var pattern = new SMB2_COMPRESSION_PATTERN_PAYLOAD_V1();
PatternPayloadLength = TypeMarshal.GetBlockMemorySize(pattern);
var payloadHeader = new SMB2_COMPRESSION_PAYLOAD_HEADER();
FieldSizeOriginalPayloadSize = TypeMarshal.GetBlockMemorySize(payloadHeader.OriginalPayloadSize);
}
private static Smb2Packet CompressWithPatternV1(Smb2CompressiblePacket packet, Smb2CompressionInfo compressionInfo, Smb2Role role)
{
var data = packet.ToBytes();
var dataToCompress = data;
if (compressionInfo.CompressBufferOnly)
{
dataToCompress = data.Skip((packet as IPacketBuffer).BufferOffset).ToArray();
}
SMB2_COMPRESSION_PATTERN_PAYLOAD_V1?forwardDataPattern;
SMB2_COMPRESSION_PATTERN_PAYLOAD_V1?backwardDataPattern;
ScanForPatternV1(dataToCompress, out forwardDataPattern, out backwardDataPattern);
if (forwardDataPattern == null && backwardDataPattern == null)
{
// Regress to non-chained since no pattern is found at front or end.
return(CompressForNonChained(packet, compressionInfo, role));
}
var result = new Smb2ChainedCompressedPacket();
result.OriginalPacket = packet;
result.Header = new Compression_Transform_Header();
result.Header.ProtocolId = Smb2Consts.ProtocolIdInCompressionTransformHeader;
result.Header.OriginalCompressedSegmentSize = (UInt32)data.Length;
result.Header.Flags = Compression_Transform_Header_Flags.SMB2_COMPRESSION_FLAG_CHAINED;
var payloads = new List <Tuple <SMB2_COMPRESSION_PAYLOAD_HEADER, object> >();
bool isFirst = true;
if (compressionInfo.CompressBufferOnly)
{
var header = data.Take((packet as IPacketBuffer).BufferOffset).ToArray();
var payloadHeader = SMB2_COMPRESSION_PAYLOAD_HEADER.Create(CompressionAlgorithm.NONE, (UInt32)header.Length, 0, ref isFirst);
payloads.Add(new Tuple <SMB2_COMPRESSION_PAYLOAD_HEADER, object>(payloadHeader, header));
}
if (forwardDataPattern != null)
{
var payloadHeader = SMB2_COMPRESSION_PAYLOAD_HEADER.Create(CompressionAlgorithm.Pattern_V1, (UInt32)PatternPayloadLength, 0, ref isFirst);
payloads.Add(new Tuple <SMB2_COMPRESSION_PAYLOAD_HEADER, object>(payloadHeader, forwardDataPattern));
}
int forwardDataPatternLength = (int)(forwardDataPattern?.Repetitions ?? 0);
int backwardDataPatternLength = (int)(backwardDataPattern?.Repetitions ?? 0);
var innerData = dataToCompress.Skip(forwardDataPatternLength).Take(dataToCompress.Length - forwardDataPatternLength - backwardDataPatternLength).ToArray();
if (innerData.Length > 0)
{
var innerPayload = ChainedCompressWithCompressionAlgorithm(innerData, compressionInfo, ref isFirst);
payloads.Add(innerPayload);
}
if (backwardDataPattern != null)
{
var payloadHeader = SMB2_COMPRESSION_PAYLOAD_HEADER.Create(CompressionAlgorithm.Pattern_V1, (UInt32)PatternPayloadLength, 0, ref isFirst);
payloads.Add(new Tuple <SMB2_COMPRESSION_PAYLOAD_HEADER, object>(payloadHeader, backwardDataPattern));
}
result.Payloads = payloads.ToArray();
return(result);
}
