//tasks used by each constructor path
private void init()
{
//not really sure what the capture device is, I think it refers to the NIC
device = CaptureDeviceList.New()[3]; //better than .instance[3] apparently, according to author
device.Open(); //opens device, whatever that means
//TCP packet is the payload of the IP packet
//TcpPacket tcpPacket = new TcpPacket(localPort, destPort); //creates empty packet and sets the source and destination ports <port>
//tcpPacket.Flags = 0x02; //syn flag
//tcpPacket.WindowSize = 64240;
UdpPacket udpPacket = new UdpPacket(localPort, destPort);
//IP packet delivers TCP packet as its payload. IP packet is the payload of the Ethernet packet going to the gateway
IPv4Packet ipPacket = new IPv4Packet(srcAddress, destAddress);
ipPacket.TotalLength = 52;
ipPacket.Id = 0xa144;
ipPacket.FragmentFlags = 0x40;
ipPacket.TimeToLive = 128;
//Ethernet packet delivers the IP packet to the gateway
PhysicalAddress srcMAC = getLocalMAC();
//Console.WriteLine(srcMAC); //just check that it is getting the right one, otherwise you'll have to enter it manually
ethernetPacket = new EthernetPacket(srcMAC, destMAC, EthernetType.None);
//matryoshka doll the packets
ethernetPacket.PayloadPacket = ipPacket;
ipPacket.PayloadPacket = udpPacket;
//this may need to be moved elsewhere incase time factors into the checksum
udpPacket.Checksum = udpPacket.CalculateUdpChecksum();
ipPacket.Checksum = ipPacket.CalculateIPChecksum();
sendTimer = new Timer();
sendTimer.Elapsed += new ElapsedEventHandler(sendPacket); //method to be done every interval
sendTimer.Enabled = true; //does not start timer, it means the method will be done every interval
}