private void ParseHeader(RawDGram p, int len)
{
Console.WriteLine("Parsing Header");
IPHeader header = new IPHeader(p.rawBytes, len);
switch (header.ProtocolType)
{
case Protocol.ICMP:
ICMPHeader icmpHeader = new ICMPHeader(header.Data, header.MessageLength);
//Console.WriteLine(String.Format("ICMP type: {0} code: {1}", icmpHeader.Type, icmpHeader.Code));
if (icmpHeader.Type == ICMPHeader.ICMPTypes.DestinationUnreachable && icmpHeader.Code == 3)
{
//Binary search the MTU (this is used during the probe phase of some congestion control
//algorithms. Also, the initial congestion window should be calculated in terms of bytes i.e. (mtu/windowsize = packets)
}
break;
case Protocol.TCP:
//Console.WriteLine("TCP packet received");
break;
case Protocol.UDP:
UDPHeader udpHeader = new UDPHeader(header.Data, header.MessageLength);
HandleUDP(header, udpHeader);
break;
case Protocol.Unknown:
//Console.WriteLine("Unknown packet received");
break;
default:
throw new ArgumentOutOfRangeException();
}
}
private void OnPacketRecieved(IAsyncResult ar)
{
Console.WriteLine("Data received");
RawDGram p = (RawDGram)ar.AsyncState;
int len = socket.EndReceiveFrom(ar, ref p.sender);
readerEvent.Set();
//this can be pushed off to a task or threadpool
ParseHeader(p, len);
}
private void StartRecievingPackets()
{
byte[] byTrue = new byte[4] {
1, 0, 0, 0
};
byte[] byOut = new byte[4];
this.socket.IOControl(IOControlCode.ReceiveAll, byTrue, byOut);
while (this.isOn)
{
Console.WriteLine("Entering receive loop");
readerEvent.Reset();
RawDGram p = new RawDGram(this.mtu, ep);
socket.BeginReceiveFrom(p.rawBytes,
0,
p.rawBytes.Length,
SocketFlags.None,
ref p.sender,
new AsyncCallback(OnPacketRecieved),
p);
readerEvent.WaitOne();
}
}
