internal static void HandlePacket(byte[] payload)
{
bool SYN = (payload[47] & (1<<1)) != 0; // Synchronize
bool ACK = (payload[47] & (1<<4)) != 0; // Acknoledge
bool FIN = (payload[47] & (1<<0)) != 0; // Finish
bool PSH = (payload[47] & (1<<3)) != 0; // Push
bool RST = (payload[47] & (1<<2)) != 0; // Reset
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 = null;
//TODO: Validate TCP checksum and reject packet if invalid!
uint packetSeqNumber = Utility.ExtractRangeFromArray(payload, 38, 4).ToInt();
// Handle a new request
// if this is a new connection SYN, add to the Connections collection
if (SYN && !ACK) // new connection
{
//Debug.WriteLine("SYN");
if (Connections.Contains(connectionID) && (Connections[connectionID] as Connection).IsOpen) Connections.Remove(connectionID); // remove old connection?
// Prune old Connections
var keys = new ulong[Connections.Count];
Connections.Keys.CopyTo(keys, 0);
foreach (var key in keys)
{
con = Connections[key] as Connection;
if (Microsoft.SPOT.Hardware.Utility.GetMachineTime().Subtract((Connections[key] as Connection).LastActivity).Seconds > ConnectionIdleLimit)
{
con.isClosing = true;
//Adapter.StopListeningToPort(con.LocalPort);
//Debug.WriteLine("FIN -- Closing idle connection");
con.SeqNumber++;
con.SendAck(false, true); // SendAck Fin/Ack
Connections.Remove(key);
}
}
if (!Connections.Contains(connectionID)) Connections.Add(connectionID, new Connection());
con = Connections[connectionID] as Connection;
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; //Utility.ExtractRangeFromArray(payload, 42, 4).ToInt(), //TODO: this should be a random number initially?
con.WindowSize = 1024; //Utility.ExtractRangeFromArray(payload, 48, 2).ToShort()
con.ReadyForRequest = true;
con.SendAck(true); // Syn/Ack
con.AckNumber++;
con.IsOpen = true; // This needs to be last because a call to the Connection.Open() may be blocked until this property gets set!
}
else if (Connections.Contains(connectionID) && (ACK || FIN || PSH || RST))
{
con = Connections[connectionID] as Connection;
ushort totalLength = Utility.ExtractRangeFromArray(payload, 16, 2).ToShort();
ushort ipHeaderLength = (ushort)((payload[14] & 0x0f) * 4);
ushort tcpHeaderLength = (ushort)((payload[26 + ipHeaderLength] >> 4) * 4);
if (totalLength + 14 > payload.Length)
{
// No Good -- Does not account for 0 padding?
Debug.WriteLine("Bad packet size detected? " + totalLength.ToString() + "/" + payload.Length.ToString());
return;
}
//Debug.WriteLine("1 - con.seqnum = " + con.SeqNumber);
con.SeqNumber += (uint)(totalLength - (tcpHeaderLength + ipHeaderLength));
con.WindowSize -= (ushort)(totalLength - (tcpHeaderLength + ipHeaderLength));
//Debug.WriteLine("2 - con.seqnum = " + con.SeqNumber);
if (PSH)
{
//Debug.WriteLine("PSH");
con.SendAck(); // PSH indicates we want an ACK after this packet?
}
else if (SYN && ACK)
{
con.SeqNumber = packetSeqNumber + 1;
con.StartSeqNumber = packetSeqNumber;
con.AckNumber++;
con.SendAck();
con.IsOpen = true;
return;
}
else if ((FIN || RST) && ACK)
{
// Debug.WriteLine("FIN/RST + ACK");
con.isClosing = true;
//Adapter.StopListeningToPort(con.LocalPort);
con.SeqNumber++;
con.SendAck();
// This is an ACKnowledgement that the connection is now closed, so delete it.
Connections.Remove(connectionID);
return;
}
else if (FIN)
{
con.isClosing = true;
//Adapter.StopListeningToPort(con.LocalPort);
// Debug.WriteLine("FIN");
con.SeqNumber++;
con.SendAck(false, true);
return;
}
else if (RST)
{
con.isClosing = true;
//Adapter.StopListeningToPort(con.LocalPort);
// Debug.WriteLine("FIN");
con.SeqNumber++;
//con.SendAck(false, true);
return;
}
else if (ACK && con.isClosing)
{
// Debug.WriteLine("ACK + Closing");
// This is an ACKnowledgement that the connection is now closed, so delete it.
//Adapter.StopListeningToPort(con.LocalPort);
Connections.Remove(connectionID);
return;
}
if (Adapter.VerboseDebugging) Debug.WriteLine("Check for data");
//We got some data!?
if ((totalLength - (tcpHeaderLength + ipHeaderLength)) > 0)
{
byte[] segment = Utility.ExtractRangeFromArray(payload, (14 + ipHeaderLength + tcpHeaderLength), (totalLength - (tcpHeaderLength + ipHeaderLength)));
if (Adapter.VerboseDebugging) Debug.WriteLine("got some data, psn: " + packetSeqNumber.ToString() + ", ssn: " + con.StartSeqNumber.ToString() + ", header delim: " + segment.Locate(HttpRequest.HeaderDelimiter).ToString());
Networking.Adapter.FireTcpPacketEvent(segment, packetSeqNumber - con.StartSeqNumber, con); // TCP events always fire
con.FireOnConnectionPacketReceived(new Packet(PacketType.TCP) { SequenceNumber = packetSeqNumber - con.StartSeqNumber, Content = segment, Socket = con });
// Filters out anything that is not a GET or POST Http VERB (I did a byte comparison to avoid utf decoding exceptions, since we don't know that we actually have text yet)
//if (packetSeqNumber - con.StartSeqNumber == 1)
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 (packetSeqNumber - con.StartSeqNumber == 1) // && segment.Locate(HttpRequest.HeaderDelimiter) > -1)
if (con.ReadyForRequest)
{
// get the TCP checksum from the current packet and make sure it does not match the last request for we start...
byte[] lrc = Utility.ExtractRangeFromArray(payload, (30 + ipHeaderLength), 2);
if (con.LastRequestChecksum.BytesEqual(lrc))
{
if (Adapter.VerboseDebugging) Debug.WriteLine("Retransmission of Request Ignored!");
}
else
{
con.LastRequestChecksum = lrc;
con.ReadyForRequest = false;
Networking.Adapter.FireHttpPacketEvent(segment, con);
}
}
}
}
else if ((FIN || RST) && ACK)
{
//Debug.WriteLine("Handling RST for a connection that no longer exists!!!!!!!!!");
con = new Connection();
con.RemoteIP = SourceIP;
con.RemotePort = SourcePort.ToShort();
con.RemoteMac = Utility.ExtractRangeFromArray(payload, 6, 6);
con.LocalPort = LocalPort.ToShort();
con.SeqNumber = Utility.ExtractRangeFromArray(payload, 38, 4).ToInt();
con.AckNumber = Utility.ExtractRangeFromArray(payload, 42, 4).ToInt();
con.isClosing = true;
//Adapter.StopListeningToPort(con.LocalPort);
con.SendAck();
return;
}
}
internal static void HandlePacket(byte[] payload)
{
bool SYN = (payload[47] & (1 << 1)) != 0; // Synchronize
bool ACK = (payload[47] & (1 << 4)) != 0; // Acknoledge
bool FIN = (payload[47] & (1 << 0)) != 0; // Finish
bool PSH = (payload[47] & (1 << 3)) != 0; // Push
bool RST = (payload[47] & (1 << 2)) != 0; // Reset
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 = null;
//TODO: Validate TCP checksum and reject packet if invalid!
uint packetSeqNumber = Utility.ExtractRangeFromArray(payload, 38, 4).ToInt();
// Handle a new request
// if this is a new connection SYN, add to the Connections collection
if (SYN && !ACK) // new connection
{
//Debug.WriteLine("SYN");
if (Connections.Contains(connectionID) && (Connections[connectionID] as Connection).IsOpen)
{
Connections.Remove(connectionID); // remove old connection?
}
// Prune old Connections
var keys = new ulong[Connections.Count];
Connections.Keys.CopyTo(keys, 0);
foreach (var key in keys)
{
con = Connections[key] as Connection;
if (Microsoft.SPOT.Hardware.Utility.GetMachineTime().Subtract((Connections[key] as Connection).LastActivity).Seconds > ConnectionIdleLimit)
{
con.isClosing = true;
//Adapter.StopListeningToPort(con.LocalPort);
//Debug.WriteLine("FIN -- Closing idle connection");
con.SeqNumber++;
con.SendAck(false, true); // SendAck Fin/Ack
Connections.Remove(key);
}
}
if (!Connections.Contains(connectionID))
{
Connections.Add(connectionID, new Connection());
}
con = Connections[connectionID] as Connection;
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; //Utility.ExtractRangeFromArray(payload, 42, 4).ToInt(), //TODO: this should be a random number initially?
con.WindowSize = 1024; //Utility.ExtractRangeFromArray(payload, 48, 2).ToShort()
con.ReadyForRequest = true;
con.SendAck(true); // Syn/Ack
con.AckNumber++;
con.IsOpen = true; // This needs to be last because a call to the Connection.Open() may be blocked until this property gets set!
}
else if (Connections.Contains(connectionID) && (ACK || FIN || PSH || RST))
{
con = Connections[connectionID] as Connection;
ushort totalLength = Utility.ExtractRangeFromArray(payload, 16, 2).ToShort();
ushort ipHeaderLength = (ushort)((payload[14] & 0x0f) * 4);
ushort tcpHeaderLength = (ushort)((payload[26 + ipHeaderLength] >> 4) * 4);
if (totalLength + 14 > payload.Length)
{
// No Good -- Does not account for 0 padding?
Debug.WriteLine("Bad packet size detected? " + totalLength.ToString() + "/" + payload.Length.ToString());
return;
}
//Debug.WriteLine("1 - con.seqnum = " + con.SeqNumber);
con.SeqNumber += (uint)(totalLength - (tcpHeaderLength + ipHeaderLength));
con.WindowSize -= (ushort)(totalLength - (tcpHeaderLength + ipHeaderLength));
//Debug.WriteLine("2 - con.seqnum = " + con.SeqNumber);
if (PSH)
{
//Debug.WriteLine("PSH");
con.SendAck(); // PSH indicates we want an ACK after this packet?
}
else if (SYN && ACK)
{
con.SeqNumber = packetSeqNumber + 1;
con.StartSeqNumber = packetSeqNumber;
con.AckNumber++;
con.SendAck();
con.IsOpen = true;
return;
}
else if ((FIN || RST) && ACK)
{
// Debug.WriteLine("FIN/RST + ACK");
con.isClosing = true;
//Adapter.StopListeningToPort(con.LocalPort);
con.SeqNumber++;
con.SendAck();
// This is an ACKnowledgement that the connection is now closed, so delete it.
Connections.Remove(connectionID);
return;
}
else if (FIN)
{
con.isClosing = true;
//Adapter.StopListeningToPort(con.LocalPort);
// Debug.WriteLine("FIN");
con.SeqNumber++;
con.SendAck(false, true);
return;
}
else if (RST)
{
con.isClosing = true;
//Adapter.StopListeningToPort(con.LocalPort);
// Debug.WriteLine("FIN");
con.SeqNumber++;
//con.SendAck(false, true);
return;
}
else if (ACK && con.isClosing)
{
// Debug.WriteLine("ACK + Closing");
// This is an ACKnowledgement that the connection is now closed, so delete it.
//Adapter.StopListeningToPort(con.LocalPort);
Connections.Remove(connectionID);
return;
}
if (Adapter.VerboseDebugging)
{
Debug.WriteLine("Check for data");
}
//We got some data!?
if ((totalLength - (tcpHeaderLength + ipHeaderLength)) > 0)
{
byte[] segment = Utility.ExtractRangeFromArray(payload, (14 + ipHeaderLength + tcpHeaderLength), (totalLength - (tcpHeaderLength + ipHeaderLength)));
if (Adapter.VerboseDebugging)
{
Debug.WriteLine("got some data, psn: " + packetSeqNumber.ToString() + ", ssn: " + con.StartSeqNumber.ToString() + ", header delim: " + segment.Locate(HttpRequest.HeaderDelimiter).ToString());
}
Networking.Adapter.FireTcpPacketEvent(segment, packetSeqNumber - con.StartSeqNumber, con); // TCP events always fire
con.FireOnConnectionPacketReceived(new Packet(PacketType.TCP)
{
SequenceNumber = packetSeqNumber - con.StartSeqNumber, Content = segment, Socket = con
});
// Filters out anything that is not a GET or POST Http VERB (I did a byte comparison to avoid utf decoding exceptions, since we don't know that we actually have text yet)
//if (packetSeqNumber - con.StartSeqNumber == 1)
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 (packetSeqNumber - con.StartSeqNumber == 1) // && segment.Locate(HttpRequest.HeaderDelimiter) > -1)
if (con.ReadyForRequest)
{
// get the TCP checksum from the current packet and make sure it does not match the last request for we start...
byte[] lrc = Utility.ExtractRangeFromArray(payload, (30 + ipHeaderLength), 2);
if (con.LastRequestChecksum.BytesEqual(lrc))
{
if (Adapter.VerboseDebugging)
{
Debug.WriteLine("Retransmission of Request Ignored!");
}
}
else
{
con.LastRequestChecksum = lrc;
con.ReadyForRequest = false;
Networking.Adapter.FireHttpPacketEvent(segment, con);
}
}
}
}
else if ((FIN || RST) && ACK)
{
//Debug.WriteLine("Handling RST for a connection that no longer exists!!!!!!!!!");
con = new Connection();
con.RemoteIP = SourceIP;
con.RemotePort = SourcePort.ToShort();
con.RemoteMac = Utility.ExtractRangeFromArray(payload, 6, 6);
con.LocalPort = LocalPort.ToShort();
con.SeqNumber = Utility.ExtractRangeFromArray(payload, 38, 4).ToInt();
con.AckNumber = Utility.ExtractRangeFromArray(payload, 42, 4).ToInt();
con.isClosing = true;
//Adapter.StopListeningToPort(con.LocalPort);
con.SendAck();
return;
}
}
