/// <summary>
/// Append a CRC checksum and encrypt data in place using XTEA
/// </summary>
internal void EncryptSymmetric(NetBuffer buffer)
{
//string plain = Convert.ToBase64String(buffer.Data, 0, buffer.LengthBytes);
int bufferLen = buffer.LengthBytes;
// calculate number of pad bits
int dataBits = buffer.LengthBits;
int bitsNeeded = dataBits + 24; // 24 extra for crc and num-pad-bits
int totalBits = bitsNeeded + (64 - (bitsNeeded % 64));
int padBits = totalBits - bitsNeeded;
// write to ensure zeroes in buffer (crc and num-pad-bits space)
buffer.Write((uint)0, 24);
if (padBits > 0)
{
buffer.Write((ulong)0, padBits);
}
int writePadBitsPosition = buffer.LengthBits - 8;
// write crc
ushort crc = Checksum.Adler16(buffer.Data, 0, buffer.LengthBytes);
buffer.ResetWritePointer(dataBits);
buffer.Write(crc);
// write num-pad-bits in LAST byte
buffer.ResetWritePointer(writePadBitsPosition);
buffer.Write((byte)padBits);
// encrypt in place
int ptr = 0;
bufferLen = buffer.LengthBytes;
while (ptr < bufferLen)
{
m_xtea.EncryptBlock(buffer.Data, ptr, buffer.Data, ptr);
ptr += 8;
}
return;
}
// unsequenced packets only, returns number of bytes sent
internal int SendSingleMessageAtOnce(NetMessage msg, NetConnection connection, IPEndPoint endpoint)
{
m_sendBuffer.ResetWritePointer();
msg.Encode(connection, m_sendBuffer);
if (connection != null)
{
return(ExecuteSend(m_sendBuffer, connection, connection.RemoteEndpoint));
}
else
{
return(ExecuteSend(m_sendBuffer, null, endpoint));
}
}
/// <summary>
/// Decrypt using XTEA algo and verify CRC
/// </summary>
/// <returns>true for success, false for failure</returns>
internal bool DecryptSymmetric(NetBuffer buffer)
{
int bufLen = buffer.LengthBytes;
if (bufLen % 8 != 0)
{
if (NetBase.CurrentContext != null && NetBase.CurrentContext.Log != null)
{
NetBase.CurrentContext.Log.Info("Bad buffer size in DecryptSymmetricInPlace()");
}
return(false);
}
//NetBase.CurrentContext.Log.Debug.Debug("Decrypting using key: " + Convert.ToBase64String(m_xtea.Key));
// decrypt
for (int i = 0; i < bufLen; i += 8)
{
m_xtea.DecryptBlock(buffer.Data, i, buffer.Data, i);
}
int numPadBits = buffer.Data[bufLen - 1];
buffer.Data[bufLen - 1] = 0; // zap for correct crc calculation
int dataBits = (bufLen * 8) - (24 + numPadBits); // include pad and crc
buffer.ResetReadPointer(dataBits);
ushort statedCrc = buffer.ReadUInt16();
// zap crc to be able to compare
buffer.ResetWritePointer(dataBits);
buffer.Write((ushort)0);
ushort dataCrc = Checksum.Adler16(buffer.Data, 0, bufLen);
//NetBase.CurrentContext.Log.Debug("Plain (len " + bufLen + "): " + Convert.ToBase64String(buffer.Data, 0, bufLen) + " Stated CRC: " + statedCrc + " Calc: " + realCrc);
if (statedCrc != dataCrc)
{
if (NetBase.CurrentContext != null && NetBase.CurrentContext.Log != null)
{
NetBase.CurrentContext.Log.Warning("CRC failure; expected " + dataCrc + " found " + statedCrc + " dropping packet!");
}
return(false);
}
// clean up
buffer.LengthBits = dataBits;
buffer.ResetReadPointer();
return(true);
}
internal void SendUnsentMessages(bool forceAcks, double frameLength)
{
if (m_unsentMessages.Count < 1 && !forceAcks)
{
if (m_status == NetConnectionStatus.Disconnecting)
{
SetStatus(NetConnectionStatus.Disconnected, m_pendingDisconnectedReason);
}
return; // nothing to send
}
//if (m_unsentMessages.Count < 1 && forceAcks)
// m_parent.Log.Debug("FORCING EXPLICIT ACK");
float sendBytesAllowed = (float)frameLength * (float)Configuration.ThrottleBytesPerSecond;
if (m_throttleDebt > sendBytesAllowed)
{
// NetBase.CurrentContext.Log.Debug("Working off debt: " + m_throttleDebt + " bytes by " + sendBytesAllowed");
m_throttleDebt -= sendBytesAllowed;
return;
}
else if (m_throttleDebt > 0)
{
sendBytesAllowed -= m_throttleDebt;
m_throttleDebt = 0;
}
NetBuffer sendBuffer = m_parent.m_sendBuffer;
sendBuffer.ResetWritePointer();
int mtu = m_parent.Configuration.MaximumTransmissionUnit;
float now = (float)NetTime.Now;
int pktMsgAdded = 0;
int ackMsgAdded = 0;
int usrMsgAdded = 0;
NetMessage msg;
// TODO: make ack bitfield if possible
while (m_unsentAcknowledges.Count > 0 && sendBytesAllowed > 0)
{
msg = m_unsentAcknowledges.Dequeue();
m_reusedAckMessage.SequenceChannel = msg.SequenceChannel;
m_reusedAckMessage.SequenceNumber = msg.SequenceNumber;
if (sendBuffer.LengthBytes + 3 > mtu)
{
// send buffer
m_parent.ExecuteSend(sendBuffer, this, m_remoteEndpoint);
sendBytesAllowed -= sendBuffer.LengthBytes;
Statistics.PacketsSent++;
Statistics.MessagesSent += pktMsgAdded;
Statistics.AckMessagesSent += ackMsgAdded;
Statistics.BytesSent += sendBuffer.LengthBytes;
sendBuffer.ResetWritePointer();
pktMsgAdded = 0;
ackMsgAdded = 0;
}
//m_parent.Log.Debug("Sending ack " + msg.SequenceChannel + "|" + msg.SequenceNumber);
m_reusedAckMessage.Encode(this, sendBuffer);
pktMsgAdded++;
ackMsgAdded++;
}
// no unsent acks left!
m_forceExplicitAckTime = 0.0;
while (m_unsentMessages.Count > 0 && sendBytesAllowed > 0)
{
msg = m_unsentMessages.Dequeue();
// make pessimistic estimate of message length
int estMsgLen = msg.EstimateEncodedLength();
if (sendBuffer.LengthBytes + estMsgLen > mtu)
{
if (pktMsgAdded < 1)
{
throw new NetException("Message too large to send: " + estMsgLen + " bytes: " + msg);
}
// send buffer
m_parent.ExecuteSend(sendBuffer, this, m_remoteEndpoint);
sendBytesAllowed -= sendBuffer.LengthBytes;
Statistics.PacketsSent++;
Statistics.MessagesSent += pktMsgAdded;
Statistics.UserMessagesSent += usrMsgAdded;
Statistics.AckMessagesSent += ackMsgAdded;
Statistics.BytesSent += sendBuffer.LengthBytes;
sendBuffer.ResetWritePointer();
pktMsgAdded = 0;
ackMsgAdded = 0;
}
msg.Encode(this, sendBuffer);
if (msg.m_type == NetMessageType.User || msg.m_type == NetMessageType.UserFragmented)
{
usrMsgAdded++;
}
pktMsgAdded++;
// store until acknowledged
if (msg.SequenceChannel >= NetChannel.ReliableUnordered)
{
float nextResend = now + (msg.m_numResends < 1 ? Configuration.ResendFirstUnacknowledgedDelay : Configuration.ResendSubsequentUnacknowledgedDelay);
msg.m_nextResendTime = nextResend;
//m_parent.Log.Debug("Storing " + msg.SequenceChannel + "|" + msg.SequenceNumber + " @ " + now + " first resend: " + nextResend);
int seqChan = (int)msg.SequenceChannel;
if (m_savedReliableMessages[seqChan] == null)
{
m_savedReliableMessages[seqChan] = new List <NetMessage>();
}
m_savedReliableMessages[seqChan].Add(msg);
}
}
if (pktMsgAdded > 0)
{
m_parent.ExecuteSend(sendBuffer, this, m_remoteEndpoint);
sendBytesAllowed -= sendBuffer.LengthBytes;
Statistics.PacketsSent++;
Statistics.MessagesSent += pktMsgAdded;
Statistics.UserMessagesSent += usrMsgAdded;
Statistics.AckMessagesSent += ackMsgAdded;
Statistics.BytesSent += sendBuffer.LengthBytes;
}
Debug.Assert(m_throttleDebt == 0);
if (sendBytesAllowed < 0)
{
m_throttleDebt = -sendBytesAllowed;
}
}
/// <summary>
/// Decrypt using XTEA algo and verify CRC
/// </summary>
/// <returns>true for success, false for failure</returns>
internal bool DecryptSymmetric(NetBuffer buffer)
{
int bufLen = buffer.LengthBytes;
if (bufLen % 8 != 0)
{
if (NetBase.CurrentContext != null && NetBase.CurrentContext.Log != null)
NetBase.CurrentContext.Log.Info("Bad buffer size in DecryptSymmetricInPlace()");
return false;
}
//NetBase.CurrentContext.Log.Debug.Debug("Decrypting using key: " + Convert.ToBase64String(m_xtea.Key));
// decrypt
for (int i = 0; i < bufLen; i += 8)
m_xtea.DecryptBlock(buffer.Data, i, buffer.Data, i);
int numPadBits = buffer.Data[bufLen - 1];
buffer.Data[bufLen - 1] = 0; // zap for correct crc calculation
int dataBits = (bufLen * 8) - (24 + numPadBits); // include pad and crc
buffer.ResetReadPointer(dataBits);
ushort statedCrc = buffer.ReadUInt16();
// zap crc to be able to compare
buffer.ResetWritePointer(dataBits);
buffer.Write((ushort)0);
ushort dataCrc = Checksum.Adler16(buffer.Data, 0, bufLen);
//NetBase.CurrentContext.Log.Debug("Plain (len " + bufLen + "): " + Convert.ToBase64String(buffer.Data, 0, bufLen) + " Stated CRC: " + statedCrc + " Calc: " + realCrc);
if (statedCrc != dataCrc)
{
if (NetBase.CurrentContext != null && NetBase.CurrentContext.Log != null)
NetBase.CurrentContext.Log.Warning("CRC failure; expected " + dataCrc + " found " + statedCrc + " dropping packet!");
return false;
}
// clean up
buffer.LengthBits = dataBits;
buffer.ResetReadPointer();
return true;
}
/// <summary>
/// Append a CRC checksum and encrypt data in place using XTEA
/// </summary>
internal void EncryptSymmetric(NetBuffer buffer)
{
//string plain = Convert.ToBase64String(buffer.Data, 0, buffer.LengthBytes);
int bufferLen = buffer.LengthBytes;
// calculate number of pad bits
int dataBits = buffer.LengthBits;
int bitsNeeded = dataBits + 24; // 24 extra for crc and num-pad-bits
int totalBits = bitsNeeded + (64 - (bitsNeeded % 64));
int padBits = totalBits - bitsNeeded;
// write to ensure zeroes in buffer (crc and num-pad-bits space)
buffer.Write((uint)0, 24);
if (padBits > 0)
buffer.Write((ulong)0, padBits);
int writePadBitsPosition = buffer.LengthBits - 8;
// write crc
ushort crc = Checksum.Adler16(buffer.Data, 0, buffer.LengthBytes);
buffer.ResetWritePointer(dataBits);
buffer.Write(crc);
// write num-pad-bits in LAST byte
buffer.ResetWritePointer(writePadBitsPosition);
buffer.Write((byte)padBits);
// encrypt in place
int ptr = 0;
bufferLen = buffer.LengthBytes;
while (ptr < bufferLen)
{
m_xtea.EncryptBlock(buffer.Data, ptr, buffer.Data, ptr);
ptr += 8;
}
return;
}
