internal static void HandlePacket(byte[] payload)
{
// ReSharper disable InconsistentNaming
bool SYN = (payload[47] & (1 << 1)) != 0;
var ACK = (payload[47] & (1 << 4)) != 0;
bool FIN = (payload[47] & (1 << 0)) != 0;
bool PSH = (payload[47] & (1 << 3)) != 0;
bool RST = (payload[47] & (1 << 2)) != 0;
// ReSharper restore InconsistentNaming
byte[] sourceIp = Utility.ExtractRangeFromArray(payload, 26, 4);
byte[] sourcePort = Utility.ExtractRangeFromArray(payload, 34, 2);
byte[] localPort = Utility.ExtractRangeFromArray(payload, 36, 2);
ulong connectionId = GenerateConnectionId(payload);
Connection con;
uint packetSeqNumber = Utility.ExtractRangeFromArray(payload, 38, 4).ToInt();
if (SYN && !ACK)
{
var connection = _connections[connectionId] as Connection;
if (connection != null && (_connections.Contains(connectionId) && connection.IsOpen))
{
_connections.Remove(connectionId);
}
var keys = new ulong[_connections.Count];
_connections.Keys.CopyTo(keys, 0);
foreach (ulong key in keys)
{
con = _connections[key] as Connection;
var connection1 = _connections[key] as Connection;
if (connection1 != null &&
Utility.GetMachineTime().Subtract(connection1.LastActivity).Seconds > ConnectionIdleLimit)
{
con.IsClosing = true;
con.SeqNumber++;
con.SendAck(false, true);
_connections.Remove(key);
}
}
if (!_connections.Contains(connectionId))
{
_connections.Add(connectionId, new Connection());
}
con = _connections[connectionId] as Connection;
if (con != null)
{
con.RemoteIp = sourceIp;
con.RemotePort = sourcePort.ToShort();
con.RemoteMac = Utility.ExtractRangeFromArray(payload, 6, 6);
con.LocalPort = localPort.ToShort();
con.SeqNumber = packetSeqNumber + 1;
con.StartSeqNumber = packetSeqNumber;
con.AckNumber = 2380;
con.WindowSize = 1024;
con.ReadyForRequest = true;
con.SendAck(true);
con.AckNumber++;
con.IsOpen = true;
}
}
else if (_connections.Contains(connectionId) && (ACK || FIN || PSH || RST))
{
con = _connections[connectionId] as Connection;
ushort totalLength = Utility.ExtractRangeFromArray(payload, 16, 2).ToShort();
var ipHeaderLength = (ushort)((payload[14] & 0x0f) * 4);
var tcpHeaderLength = (ushort)((payload[26 + ipHeaderLength] >> 4) * 4);
if (totalLength + 14 > payload.Length)
{
#if TINYCLR_TRACE
if (EthClick._verboseDebugging)
{
System.Diagnostics.Debug.WriteLine("Bad packet size detected? " + totalLength + "/" + payload.Length);
}
#endif
return;
}
if (con != null)
{
con.SeqNumber += (uint)(totalLength - (tcpHeaderLength + ipHeaderLength));
con.WindowSize -= (ushort)(totalLength - (tcpHeaderLength + ipHeaderLength));
if (PSH)
{
con.SendAck();
}
else if (SYN)
{
con.SeqNumber = packetSeqNumber + 1;
con.StartSeqNumber = packetSeqNumber;
con.AckNumber++;
con.SendAck();
con.IsOpen = true;
return;
}
else if ((FIN || RST) && ACK)
{
con.IsClosing = true;
con.SeqNumber++;
con.SendAck();
_connections.Remove(connectionId);
return;
}
else if (FIN)
{
con.IsClosing = true;
con.SeqNumber++;
con.SendAck(false, true);
return;
}
else if (RST)
{
con.IsClosing = true;
con.SeqNumber++;
return;
}
else if (con.IsClosing)
{
_connections.Remove(connectionId);
return;
}
#if TINYCLR_TRACE
if (EthClick._verboseDebugging)
{
System.Diagnostics.Debug.WriteLine("Check for data");
}
#endif
if ((totalLength - (tcpHeaderLength + ipHeaderLength)) > 0)
{
byte[] segment = Utility.ExtractRangeFromArray(payload, (14 + ipHeaderLength + tcpHeaderLength),
(totalLength - (tcpHeaderLength + ipHeaderLength)));
#if TINYCLR_TRACE
if (EthClick._verboseDebugging)
{
System.Diagnostics.Debug.WriteLine("We got some data, PSN: " + packetSeqNumber + ", SSN: " + con.StartSeqNumber +
", header delimiter: " + segment.Locate(HttpRequest.HeaderDelimiter));
}
#endif
EthClick.FireTcpPacketEvent(segment, packetSeqNumber - con.StartSeqNumber, con);
con.FireOnConnectionPacketReceived(new Packet(PacketType.TCP)
{
SequenceNumber = packetSeqNumber - con.StartSeqNumber,
Content = segment,
Socket = con
});
if (segment.Length < 10 ||
!(segment[0] == 0x47 && segment[1] == 0x45 && segment[2] == 0x54) &&
!(segment[0] == 0x50 && segment[1] == 0x4F && segment[2] == 0x53 && segment[3] == 0x54))
{
return; // if it is not a get, then we won't handle it through the HTTP Request Handler
}
if (con.ReadyForRequest)
{
byte[] lrc = Utility.ExtractRangeFromArray(payload, (30 + ipHeaderLength), 2);
if (con.LastRequestChecksum.BytesEqual(lrc))
{
#if TINYCLR_TRACE
if (EthClick._verboseDebugging)
{
System.Diagnostics.Debug.WriteLine("Retransmission of Request Ignored!");
}
#endif
}
else
{
con.LastRequestChecksum = lrc;
con.ReadyForRequest = false;
EthClick.FireHttpPacketEvent(segment, con);
}
}
}
}
}
else if ((FIN || RST) && ACK)
{
#if TINYCLR_TRACE
if (EthClick._verboseDebugging)
{
System.Diagnostics.Debug.WriteLine("Handling RST for a connection that no longer exists!!!!!!!!!");
}
#endif
con = new Connection
{
RemoteIp = sourceIp,
RemotePort = sourcePort.ToShort(),
RemoteMac = Utility.ExtractRangeFromArray(payload, 6, 6),
LocalPort = localPort.ToShort(),
SeqNumber = Utility.ExtractRangeFromArray(payload, 38, 4).ToInt(),
AckNumber = Utility.ExtractRangeFromArray(payload, 42, 4).ToInt(),
IsClosing = true
};
con.SendAck();
}
}
