System.IO.BACnet.BacnetEthernetProtocolTransport.OnPacketArrival C# (CSharp) Méthode

        void OnPacketArrival(RawCapture packet)
        {
            // don't process any packet too short to not be valid
            if (packet.Data.Length <= 17)
                return;

            byte[] buffer = packet.Data;
            int offset = 0;

            int length;
            byte dsap, ssap, control;

            // Got frames send by me, not for me, not broadcast
            byte[] dest = Mac(buffer, offset);
            if (!_isOutboundPacket(dest, 0) && (dest[0] != 255))
                return;

            offset += 6;

            // source address
            BacnetAddress Bac_source = new BacnetAddress(BacnetAddressTypes.Ethernet, 0, Mac(buffer, offset));
            offset += 6;

            // len
            length = buffer[offset] * 256 + buffer[offset + 1];
            offset += 2;

            // 3 bytes LLC hearder
            dsap = buffer[offset++];
            ssap = buffer[offset++];
            control = buffer[offset++];

            length -= 3; // Bacnet content length eq. ethernet lenght minus LLC header length

            // don't process non-BACnet packets
            if (dsap != 0x82 || ssap != 0x82 || control != 0x03)
                return;

            if (MessageRecieved != null)
                MessageRecieved(this, buffer, HeaderLength, length, Bac_source);
        }