internal static void UpdateIcmpNode(TreeView treeView, ICMPPacket icmpPacket)
        {
            TreeNode icmpNode = treeView.Nodes["ICMP"];
            if (icmpNode == null)
            {
                icmpNode = AddIcmpNode(treeView);
            }

            icmpNode.Text = String.Format("Internet Control Message Protocol: {0}", ICMPMessage.getDescription(icmpPacket.MessageKey));
            icmpNode.Nodes["Type"].Text = String.Format("Type: {0}", icmpPacket.MessageType);
            icmpNode.Nodes["Code"].Text = String.Format("Code: {0}", icmpPacket.MessageCode);
            icmpNode.Nodes["Checksum"].Text = String.Format("Checksum: 0x{0:X4} ({1})", icmpPacket.ICMPChecksum, icmpPacket.ValidICMPChecksum ? "correct" : "incorrect");

            if (icmpPacket.IsEchoRequestOrReply)
            {
                if (icmpNode.Nodes["Id"] == null)
                {
                    icmpNode.Nodes.Add("Id", String.Empty);
                    icmpNode.Nodes.Add("SeqNumber", String.Empty);
                }
                icmpNode.Nodes["Id"].Text = String.Format("Identifier: {0}", icmpPacket.Id);
                icmpNode.Nodes["SeqNumber"].Text = String.Format("Sequence number: {0}", icmpPacket.SequenceNumber);
            }
            else if (icmpNode.Nodes["Id"] != null)
            {
                icmpNode.Nodes["Id"].Remove();
                icmpNode.Nodes["SeqNumber"].Remove();
            }
        }
        /// <summary> Convert captured packet data into an object.</summary>
        public static Packet dataToPacket(LinkLayers linkType, byte[] bytes, Timeval tv)
        {
            EthernetPacketType ethProtocol;

            // retrieve the length of the headers associated with this link layer type.
            // this length is the offset to the header embedded in the packet.
            int byteOffsetToEthernetPayload = LinkLayer.LinkLayerLength(linkType);

            // extract the protocol code for the type of header embedded in the
            // link-layer of the packet
            int offset = LinkLayer.ProtocolOffset(linkType);
            if (offset == -1)
            {
                // if there is no embedded protocol, assume IpV4
                ethProtocol = EthernetPacketType.IPv4;
            }
            else
            {
                ethProtocol = (EthernetPacketType)ArrayHelper.extractInteger(bytes, offset, EthernetFields_Fields.ETH_CODE_LEN);
            }

            string errorString;
            Packet parsedPacket = null;
            try
            {
                // try to recognize the ethernet type..
                switch (ethProtocol)
                {
                    // arp
                    case EthernetPacketType.ARP:
                        parsedPacket = new ARPPacket(byteOffsetToEthernetPayload, bytes, tv);
                        break;

                    case EthernetPacketType.IPv6:
                    case EthernetPacketType.IPv4:
                        try
                        {
                            // ethernet level code is recognized as IP, figure out what kind..
                            int ipProtocol = IPProtocol.extractProtocol(byteOffsetToEthernetPayload, bytes);
                            switch (ipProtocol)
                            {
                                case (int)IPProtocol.IPProtocolType.ICMP:
                                    parsedPacket = new ICMPPacket(byteOffsetToEthernetPayload, bytes, tv);
                                    break;

                                case (int)IPProtocol.IPProtocolType.IGMP:
                                    parsedPacket = new IGMPPacket(byteOffsetToEthernetPayload, bytes, tv);
                                    break;

                                case (int)IPProtocol.IPProtocolType.TCP:
                                    parsedPacket = new TCPPacket(byteOffsetToEthernetPayload, bytes, tv);
                                    break;

                                case (int)IPProtocol.IPProtocolType.UDP:
                                    parsedPacket = new UDPPacket(byteOffsetToEthernetPayload, bytes, tv);
                                    break;

                                // unidentified ip..
                                default:
                                    parsedPacket = new IPPacket(byteOffsetToEthernetPayload, bytes, tv);
                                    break;
                            }

                            // check that the parsed packet is valid
                            if (!parsedPacket.IsValid(out errorString))
                            {
                                throw new PcapException(errorString);
                            }
                            else
                            {
                                return parsedPacket;
                            }
                        }
                        catch
                        {
                            // error parsing the specific ip packet type, parse as a generic IPPacket
                            parsedPacket = new IPPacket(byteOffsetToEthernetPayload, bytes, tv);

                            // check that the parsed packet is valid
                            if (!parsedPacket.IsValid(out errorString))
                            {
                                throw new PcapException(errorString);
                            }
                            else
                            {
                                return parsedPacket;
                            }
                        }

                    // ethernet level code not recognized, default to anonymous packet..
                    default:
                        parsedPacket = new EthernetPacket(byteOffsetToEthernetPayload, bytes, tv);
                        break;
                }

                return parsedPacket;
            }
            catch
            {
                // we know we have at least an ethernet packet, so return that
                return new EthernetPacket(byteOffsetToEthernetPayload, bytes, tv);
            }
        }
        /// <summary> Convert captured packet data into an object.</summary>
        public static Packet dataToPacket(LinkLayers linkType, byte[] bytes, Timeval tv)
        {
            EthernetPacketType ethProtocol;

            // retrieve the length of the headers associated with this link layer type.
            // this length is the offset to the header embedded in the packet.
            int byteOffsetToEthernetPayload = LinkLayer.LinkLayerLength(linkType);

            // extract the protocol code for the type of header embedded in the
            // link-layer of the packet
            int offset = LinkLayer.ProtocolOffset(linkType);

            if (offset == -1)
            {
                // if there is no embedded protocol, assume IpV4
                ethProtocol = EthernetPacketType.IPv4;
            }
            else
            {
                ethProtocol = (EthernetPacketType)ArrayHelper.extractInteger(bytes, offset, EthernetFields_Fields.ETH_CODE_LEN);
            }

            string errorString;
            Packet parsedPacket = null;

            try
            {
                // try to recognize the ethernet type..
                switch (ethProtocol)
                {
                // arp
                case EthernetPacketType.ARP:
                    parsedPacket = new ARPPacket(byteOffsetToEthernetPayload, bytes, tv);
                    break;

                case EthernetPacketType.IPv6:
                case EthernetPacketType.IPv4:
                    try
                    {
                        // ethernet level code is recognized as IP, figure out what kind..
                        int ipProtocol = IPProtocol.extractProtocol(byteOffsetToEthernetPayload, bytes);
                        switch (ipProtocol)
                        {
                        case (int)IPProtocol.IPProtocolType.ICMP:
                            parsedPacket = new ICMPPacket(byteOffsetToEthernetPayload, bytes, tv);
                            break;

                        case (int)IPProtocol.IPProtocolType.IGMP:
                            parsedPacket = new IGMPPacket(byteOffsetToEthernetPayload, bytes, tv);
                            break;

                        case (int)IPProtocol.IPProtocolType.TCP:
                            parsedPacket = new TCPPacket(byteOffsetToEthernetPayload, bytes, tv);
                            break;

                        case (int)IPProtocol.IPProtocolType.UDP:
                            parsedPacket = new UDPPacket(byteOffsetToEthernetPayload, bytes, tv);
                            break;

                        // unidentified ip..
                        default:
                            parsedPacket = new IPPacket(byteOffsetToEthernetPayload, bytes, tv);
                            break;
                        }

                        // check that the parsed packet is valid
                        if (!parsedPacket.IsValid(out errorString))
                        {
                            throw new PcapException(errorString);
                        }
                        else
                        {
                            return(parsedPacket);
                        }
                    }
                    catch
                    {
                        // error parsing the specific ip packet type, parse as a generic IPPacket
                        parsedPacket = new IPPacket(byteOffsetToEthernetPayload, bytes, tv);

                        // check that the parsed packet is valid
                        if (!parsedPacket.IsValid(out errorString))
                        {
                            throw new PcapException(errorString);
                        }
                        else
                        {
                            return(parsedPacket);
                        }
                    }

                // ethernet level code not recognized, default to anonymous packet..
                default:
                    parsedPacket = new EthernetPacket(byteOffsetToEthernetPayload, bytes, tv);
                    break;
                }

                return(parsedPacket);
            }
            catch
            {
                // we know we have at least an ethernet packet, so return that
                return(new EthernetPacket(byteOffsetToEthernetPayload, bytes, tv));
            }
        }