public override string ToString()
{
return(Diagnostics.DumpMessage(this));
}
// On entry: ParseState is current protocol parser state.
public void ProtocolParser(byte[] buffer)
{
int bufferIndex = 0, numRead = buffer.Length;
while (bufferIndex < numRead)
{
byte b = buffer[bufferIndex++];
switch (ParseEscState)
{
case PARSE_ESC_SECOND:
ParseEscState = PARSE_ESC_START;
switch (b)
{
case ProtocolConstants.BYTE_ESC_SYNC:
if (ParseState == PARSE_SYNC)
{
continue;
}
b = ProtocolConstants.BYTE_SYNC;
break;
case ProtocolConstants.BYTE_ESC_ESC:
b = ProtocolConstants.BYTE_ESC;
break;
default:
break;
}
break;
case PARSE_ESC_START:
if (b == ProtocolConstants.BYTE_ESC)
{
ParseEscState = PARSE_ESC_SECOND;
continue;
}
else if (b == ProtocolConstants.BYTE_SYNC)
{
ParseState = PARSE_SYNC;
}
break;
default:
break;
}
switch (ParseState)
{
case PARSE_SYNC:
if (b == ProtocolConstants.BYTE_SYNC)
{
ParseState = PARSE_PID;
}
break;
case PARSE_PID:
Pid = (byte)(b & ProtocolConstants.PID_MASK);
switch (Pid)
{
case ProtocolConstants.PID_PING:
case ProtocolConstants.PID_REPLY:
case ProtocolConstants.PID_RESEND:
case ProtocolConstants.PID_CANCEL:
InputBuffer = HandshakePacket.buffer;
PktLen = ProtocolConstants.HANDSHAKE_PACKET_SIZE;
break;
case ProtocolConstants.PID_GENERAL:
case ProtocolConstants.PID_GENERAL_V:
if (IoIndex == -1) // Setup a buffer.
{
IoIndex = Manager.IoBuffersFreeHeap.Allocate();
if (IoIndex == -1)
{
ParseState = PARSE_SYNC;
continue;
}
CurrentPacket = Manager.IoBuffers[IoIndex];
}
InputBuffer = CurrentPacket.buffer;
PktLen = ProtocolConstants.GENERAL_HEADER_SIZE;
break;
default:
ParseState = PARSE_SYNC;
continue;
}
InputBuffer[ProtocolConstants.PACKET_SYNC_OFFSET] = ProtocolConstants.BYTE_SYNC;
InputBuffer[ProtocolConstants.PACKET_PID_OFFSET] = b;
DataIndex = ProtocolConstants.CHECK_START_OFFSET; // Skip over sync & pid.
ChkSum = 0;
ParseState = PARSE_HEADER;
break;
case PARSE_HEADER:
ChkSum += b;
InputBuffer[DataIndex++] = b;
if (DataIndex < PktLen)
{
break;
}
if (Pid > ProtocolConstants.PID_HANDSHAKE_MAX)
{
byte len = InputBuffer[ProtocolConstants.GENERAL_DATA_LENGTH_OFFSET];
PktLen = (byte)(len + ProtocolConstants.GENERAL_OVERHEADS_SIZE);
if (len <= (Manager.MaxPacketSize - ProtocolConstants.GENERAL_OVERHEADS_SIZE))
{
ParseState = PARSE_DATA;
break;
}
if (Settings.DebugLevel > 2)
{
Log.w(TAG, "Bad message length:" + len + ".");
}
}
else
{
if ((ChkSum % 256) == 0)
{
IoNetIf.Monitor.PerformLinkHandshake(HandshakePacket);
if (Settings.DebugLevel > 6)
{
Log.d(TAG, Diagnostics.DumpHandshake(HandshakePacket));
}
}
else
{
if (Settings.DebugLevel > 2)
{
Log.w(TAG, "Bad header chksum.");
}
}
}
ParseState = PARSE_SYNC;
break;
case PARSE_DATA:
ChkSum += b;
InputBuffer[DataIndex++] = b;
if (DataIndex < PktLen)
{
break;
}
if ((ChkSum % 256) != 0) // Xfer error, ditch packet.
{
if (Settings.DebugLevel > 2)
{
Log.w(TAG, "Bad message chksum.");
}
ParseState = PARSE_SYNC;
break;
}
// By here there is a valid packet.
// Fill in some missing details:
CurrentPacket.flagsPid = Pid;
CurrentPacket.pktLen = PktLen;
CurrentPacket.iNetIf = IoNetIf.NetIfIndex;
CurrentPacket.dNetIf = ProtocolConstants.NETIF_UNSET;
if (Settings.DebugLevel > 6)
{
Log.d(TAG, Diagnostics.DumpMessage(CurrentPacket));
}
IoNetIf.Monitor.DispatchLinkPacket(this);
ParseState = PARSE_SYNC;
break;
default:
ParseState = PARSE_SYNC;
break;
}
}
}
