Ejemplo n.º 1
0
        public void SendToRaw(IPAddress rawAddress, byte id, byte[] buf, int offset, int size)
        {
            var headerList = new ArrayList();


            var icmpHeader = new IcmpHeader();

            icmpHeader.Id       = 123;
            icmpHeader.Sequence = 24;
            icmpHeader.Type     = IcmpHeader.EchoReplyType;
            icmpHeader.Code     = IcmpHeader.EchoReplyCode;

            headerList.Add(icmpHeader);


            var myheader = new MyProtocol();

            myheader.Id = (byte)(byte.MaxValue - id);
            headerList.Add(myheader);

            byte[] sub = new byte[size];
            Array.Copy(buf, offset, sub, 0, size);

            var rawpacket = ProtocolHeader.BuildPacket(headerList, sub);

            RawSocket.BeginSendTo(rawpacket, 0, rawpacket.Length, SocketFlags.None,
                                  new IPEndPoint(rawAddress, 0),
                                  new AsyncCallback(TransportLayer.Instance().OnRawWriteComplete), rawpacket.Length);
        }
Ejemplo n.º 2
0
        private void OnRawReadComplete(IAsyncResult ia)
        {
            byte[] buf = (byte[])ia.AsyncState;

            int readed = RawSocket.EndReceive(ia);

            if (readed <= PAYLOAD_OFFSET_IP_HEADER)
            {
                Log.D("raw bytes {0} <= ip+icmp header length,removed", readed);
                return;
            }


            var ipLength = (ushort)(buf[2] * 256 + buf[3]);

            var srcAddr = new IPAddress(new byte[] { buf[12], buf[13], buf[14], buf[15] });

            var icmpWithPayloadLength = ipLength - Ipv4Header.Ipv4HeaderLength;

            Log.D("receiving from {0} ,icmp with payload should be {1} bytes", srcAddr, icmpWithPayloadLength);


            //now buf contains whole packet
            ushort checksum = IcmpHeader.ComputeChecksum(buf, Ipv4Header.Ipv4HeaderLength, icmpWithPayloadLength);

            if (checksum != 0)
            {
                Log.E("icmp checksum {0} error, removed", checksum);
                //invalid pack
                return;
            }
            var crc = new Crc();

            var  payloadLength = ipLength - PAYLOAD_OFFSET_IP_HEADER;
            byte crc8          = crc.Update(buf, MY_HEADER_OFFSET_IP_HEADER + 1, payloadLength + 1);

            byte packetCrc8 = buf[MY_HEADER_OFFSET_IP_HEADER];

            if (crc8 != packetCrc8)
            {
                Log.E("calced crc {0}!= {1} failed, removed", crc8, packetCrc8);
                return;
            }

            // all ok

            foreach (var l in Listeners)
            {
                l.OnRawRead(srcAddr, buf[MY_HEADER_OFFSET_IP_HEADER + 1], buf, PAYLOAD_OFFSET_IP_HEADER, payloadLength);
            }
        }
Ejemplo n.º 3
0
        /// <summary>

        /// This routine creates an instance of the IcmpHeader class from a byte

        /// array that is a received IGMP packet. This is useful when a packet

        /// is received from the network and the header object needs to be

        /// constructed from those values.

        /// </summary>

        /// <param name="icmpPacket">Byte array containing the binary ICMP header</param>

        /// <param name="bytesCopied">Number of bytes used in header</param>

        /// <returns>Returns the IcmpHeader object created from the byte array</returns>

        static public IcmpHeader Create(byte[] icmpPacket, ref int bytesCopied)

        {
            IcmpHeader icmpHeader = new IcmpHeader();

            int offset = 0;



            // Make sure byte array is large enough to contain an ICMP header

            if (icmpPacket.Length < IcmpHeader.IcmpHeaderLength)
            {
                return(null);
            }



            icmpHeader.icmpType = icmpPacket[offset++];

            icmpHeader.icmpCode = icmpPacket[offset++];

            icmpHeader.icmpChecksum = BitConverter.ToUInt16(icmpPacket, offset);

            offset += 2;

            icmpHeader.icmpId = BitConverter.ToUInt16(icmpPacket, offset);

            offset += 2;

            icmpHeader.icmpSequence = BitConverter.ToUInt16(icmpPacket, offset);

            bytesCopied = IcmpHeader.IcmpHeaderLength;

            return(icmpHeader);
        }