using System;
using SharpPcap;

namespace Example6
{
    public class Program
    {
        public static void Main()
        {
            var ver = Pcap.SharpPcapVersion;
            /* Print SharpPcap version */
            Console.WriteLine("SharpPcap {0}, Example6.DumpTCP.cs", ver);
            Console.WriteLine();

            /* Retrieve the device list */
            var devices = CaptureDeviceList.Instance;

            /*If no device exists, print error */
            if (devices.Count < 1)
            {
                Console.WriteLine("No device found on this machine");
                return;
            }

            Console.WriteLine("The following devices are available on this machine:");
            Console.WriteLine("----------------------------------------------------");
            Console.WriteLine();

            int i = 0;

            /* Scan the list printing every entry */
            foreach (var dev in devices)
            {
                /* Description */
                Console.WriteLine("{0}) {1} {2}", i, dev.Name, dev.Description);
                i++;
            }

            Console.WriteLine();
            Console.Write("-- Please choose a device to capture: ");
            i = int.Parse(Console.ReadLine());

            using var device = devices[i];

            //Register our handler function to the 'packet arrival' event
            device.OnPacketArrival +=
                new PacketArrivalEventHandler(device_OnPacketArrival);

            // Open the device for capturing
            int readTimeoutMilliseconds = 1000;
            device.Open(DeviceModes.Promiscuous, readTimeoutMilliseconds);

            //tcpdump filter to capture only TCP/IP packets
            string filter = "(ip and udp) or (ip and icmp)";
            device.Filter = filter;

            Console.WriteLine();
            Console.WriteLine
                ("-- The following tcpdump filter will be applied: \"{0}\"",
                filter);
            Console.WriteLine
                ("-- Listening on {0}, hit 'Ctrl-C' to exit...",
                device.Description);

            // Start capture 'INFINTE' number of packets
            device.Capture();

        }

        /// <summary>
        /// Prints the time, length, src ip, src port, dst ip and dst port
        /// for each TCP/IP packet received on the network
        /// </summary>
        private static void device_OnPacketArrival(object sender, PacketCapture e)
        {
            var time = e.Header.Timeval.Date;
            var len = e.Data.Length;
            var rawPacket = e.GetPacket();

            var packet = PacketDotNet.Packet.ParsePacket(rawPacket.LinkLayerType, rawPacket.Data);

            var udpPacket = packet.Extract<PacketDotNet.UdpPacket>();
            if (udpPacket != null)
            {
                var ipPacket = (PacketDotNet.IPPacket)udpPacket.ParentPacket;
                System.Net.IPAddress srcIp = ipPacket.SourceAddress;
                System.Net.IPAddress dstIp = ipPacket.DestinationAddress;
                int srcPort = udpPacket.SourcePort;
                int dstPort = udpPacket.DestinationPort;

                Console.WriteLine("{0}:{1} -> {2}:{3}", srcIp, srcPort, dstIp, dstPort);

            }

            var icmpPacket = packet.Extract<PacketDotNet.IcmpV4Packet>();
            if (icmpPacket != null)
            {
                var ipPacket = (PacketDotNet.IPPacket)icmpPacket.ParentPacket;
                System.Net.IPAddress srcIp = ipPacket.SourceAddress;
                System.Net.IPAddress dstIp = ipPacket.DestinationAddress;
                Console.WriteLine("ICMP {0} -> {1} {2}", srcIp,dstIp, icmpPacket.Id);
                Console.WriteLine(icmpPacket.TypeCode);
            }
        }
    }
}