private void AddFragment(IPAddress address, int id, int offset, int length)
{
if (!m_fragmentedBuffers.ContainsKey(address))
{
m_fragmentedBuffers.Add(address, new SortedList <int, byte[]>());
}
m_fragmentedBuffers[address].Add(id, new byte[length]);
W2MarshalHelper.BufferCopy(m_buffer, offset, m_fragmentedBuffers[address][id], 0, length);
m_totalFragmentsSize += length;
}
private byte[] ConsolidateFragments(IPAddress address)
{
if (!m_fragmentedBuffers.ContainsKey(address))
{
return(null);
}
// Sort based on ipheader id
m_fragmentedBuffers[address].OrderBy(kvp => kvp.Key);
// Gets the length of all the fragments together
var totalLength = m_fragmentedBuffers[address].Sum(kvp => kvp.Value.Length);
var buffer = new byte[totalLength];
var currentOffset = 0;
foreach (var kvp in m_fragmentedBuffers[address])
{
W2MarshalHelper.BufferCopy(kvp.Value, 0, buffer, currentOffset, kvp.Value.Length);
currentOffset += kvp.Value.Length;
}
return(buffer);
}
protected unsafe override void ProcessReceivedMessage(
IPHeader ipHeader, TCPHeader tcpHeader, byte *data, int dataOffset, int dataLength)
{
// OK, get the packet direction.
var direction = GetDirection(ipHeader, tcpHeader);
// OK, get the right address according to the direction.
var address = GetAddress(direction, ipHeader);
// Start the fight!
if (dataLength <= 0)
{
return;
}
else if (dataLength == 4) // Hand-shake packet.
{
var helloPacket = *(uint *)&data[dataOffset];
if (helloPacket == 0x1F11F311)
{
return;
}
}
else if (dataLength < PacketHeaderSize) // Not a valid 12-byte header.
{
return;
}
else // Data >= sizeof(PacketHeader)
{
if (m_isFragmenting) // Is a fragment
{
// If the received length is less than the first fragment length
// and the total fragments can carry at least 1 full header specified message
if (dataLength < m_firstFragmentSize &&
(m_totalFragmentsSize + dataLength) >= m_fragmentHeaderSize)
{ // Add the last fragment to the list
AddFragment(address, ipHeader.Id, dataOffset, dataLength);
// Consolidate the message into a single buffer.
var msgBuffer = ConsolidateFragments(address);
if (msgBuffer == null)
{
return;
}
var remaining = msgBuffer.Length;
var currentOffset = 0;
fixed(byte *pMsgBuffer = msgBuffer)
{ // We need a do-while loop, because we may get two messages
// glued together by tcp-fragmentation.
do
{
var pSize = *(ushort *)&pMsgBuffer[currentOffset];
W2PacketSecurity.Decrypt(pMsgBuffer, pSize, currentOffset);
var pHeader = PacketHeader.Parse(&pMsgBuffer[currentOffset]);
remaining -= pSize;
// Creates a new buffer, with only the current packet.
// This ensures that we will not use the same underlyng buffer
// because this buffer will be stored by the forms...
byte[] packetBuffer = new byte[pSize];
W2MarshalHelper.BufferCopy(msgBuffer, currentOffset, packetBuffer, 0, pSize);
PacketReceived.Raise(this, new W2PacketEventArgs(pHeader, direction, ipHeader,
tcpHeader, packetBuffer));
currentOffset += pSize;
} while (remaining >= PacketHeaderSize);
}
m_isFragmenting = false;
m_fragmentHeaderSize = 0;
m_totalFragmentsSize = 0;
m_fragmentedBuffers[address].Clear();
return;
}
else
{
AddFragment(address, ipHeader.Id, dataOffset, dataLength);
return;
}
}
if (dataLength == 120)
{
var helloPacket = *(uint *)&data[dataOffset];
if (helloPacket == 0x1F11F311)
{
dataOffset += 4;
}
}
// Gets the first ushort, which is supposed to carry the size of the packet.
var headerSize = *(ushort *)&data[dataOffset];
// Not a valid packet size.
if (headerSize < PacketHeaderSize || headerSize > MaxPacketSize)
{
return;
}
if (headerSize > dataLength) // The packet will be fragmented.
{
AddFragment(address, ipHeader.Id, dataOffset, dataLength);
m_isFragmenting = true;
m_firstFragmentSize = dataLength;
m_fragmentHeaderSize = headerSize;
return;
}
else // No Fragmentation...
{
var remaining = dataLength;
var currentOffset = dataOffset;
do
{
var pSize = *(ushort *)&data[currentOffset];
W2PacketSecurity.Decrypt(data, pSize, currentOffset);
var pHeader = PacketHeader.Parse(&data[currentOffset]);
remaining -= pSize;
// Creates a temp. buffer for the handler.
byte[] packetBuffer = new byte[pSize];
W2MarshalHelper.BufferCopy(m_buffer, currentOffset, packetBuffer, 0, pSize);
PacketReceived.Raise(this, new W2PacketEventArgs(pHeader, direction, ipHeader, tcpHeader,
packetBuffer));
currentOffset += pSize;
} while (remaining >= PacketHeaderSize);
}
}
}
