/// <summary>
/// Constructor for the ICMPv6 header which also takes a reference to the
/// encompassing IPv6 header. This is necessary since the IPv6 protocol
/// defines a pseudo header checksum which requires the checksum to be
/// calculated over fields in the ICMPv6 header and payload as well as
/// fields from the IPv6 packet.
/// </summary>
/// <param name="packetHeader">Reference to the Ipv6Header object encompassing the ICMPv6 packet</param>
public Icmpv6Header(Ipv6Header packetHeader)
: base()
{
icmpType = 0;
icmpCode = 0;
icmpChecksum = 0;
ipv6Header = packetHeader;
}
/// <summary>
/// Simple constructor for the UDP header.
/// </summary>
public UdpHeader()
: base()
{
srcPort = 0;
destPort = 0;
udpLength = 0;
udpChecksum = 0;
ipv6PacketHeader = null;
ipv4PacketHeader = null;
}
/// <summary>
/// This routine creates an instance of the Ipv6Header 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="ipv6Packet">Byte array containing the binary IPv6 header</param>
/// <param name="bytesCopied">Number of bytes used in header</param>
/// <returns>Returns the Ipv6Header object created from the byte array</returns>
public static Ipv6Header Create(byte[] ipv6Packet, ref int bytesCopied)
{
Ipv6Header ipv6Header = new Ipv6Header();
byte[] addressBytes = new byte[16];
uint tempVal = 0, tempVal2 = 0;
// Ensure byte array is large enough to contain an IPv6 header
if (ipv6Packet.Length < Ipv6Header.Ipv6HeaderLength)
return null;
tempVal = ipv6Packet[0];
tempVal = (tempVal >> 4) & 0xF;
ipv6Header.ipVersion = (byte)tempVal;
tempVal = ipv6Packet[0];
tempVal = (tempVal & 0xF) >> 4;
ipv6Header.ipTrafficClass = (byte)(tempVal | (uint)((ipv6Packet[1] >> 4) & 0xF));
tempVal2 = ipv6Packet[1];
tempVal2 = (tempVal2 & 0xF) << 16;
tempVal = ipv6Packet[2];
tempVal = tempVal << 8;
ipv6Header.ipFlow = tempVal2 | tempVal | ipv6Packet[3];
ipv6Header.ipNextHeader = ipv6Packet[4];
ipv6Header.ipHopLimit = ipv6Packet[5];
Array.Copy(ipv6Packet, 6, addressBytes, 0, 16);
ipv6Header.SourceAddress = new IPv6Address(addressBytes);
Array.Copy(ipv6Packet, 24, addressBytes, 0, 16);
ipv6Header.DestinationAddress = new IPv6Address(addressBytes);
bytesCopied = Ipv6Header.Ipv6HeaderLength;
return ipv6Header;
}
/// <summary>
/// This routine builds the appropriate ICMP echo packet depending on the
/// protocol family requested.
/// </summary>
public void BuildPingPacket()
{
// Initialize the socket if it hasn't already been done
Console.WriteLine("Building the ping packet...");
Console.WriteLine("Initializing the socket if not done yet...");
if (pingSocket == null)
{
InitializeSocket();
}
// Clear any existing headers in the list
Console.WriteLine("Clearing any existing headers in the list using Clear()...");
protocolHeaderList.Clear();
if (destEndPoint.AddressFamily == AddressFamily.InterNetwork)
{
// Create the ICMP header and initialize the members
Console.WriteLine("Creating the ICMP header and initialize the members...");
icmpHeader = new IcmpHeader();
icmpHeader.Id = pingId;
icmpHeader.Sequence = pingSequence;
icmpHeader.Type = IcmpHeader.EchoRequestType;
icmpHeader.Code = IcmpHeader.EchoRequestCode;
// Build the data payload of the ICMP echo request
Console.WriteLine("Building the data payload of the ICMP echo request...");
pingPayload = new byte[pingPayloadLength];
for (int i = 0; i < pingPayload.Length; i++)
{
pingPayload[i] = (byte)'e';
}
// Add ICMP header to the list of headers
Console.WriteLine("Adding ICMP header to the list of headers using Add()...");
protocolHeaderList.Add(icmpHeader);
}
else if (destEndPoint.AddressFamily == AddressFamily.InterNetworkV6)
{
Ipv6Header ipv6Header; // Required for pseudo header checksum
IPEndPoint localInterface;
byte[] localAddressBytes = new byte[28];
Console.WriteLine("This part is for IPv6...");
// An IPv6 header is required since the IPv6 protocol specifies that the
// pseudo header checksum needs to be calculated on ICMPv6 packets which
// requires the source and destination address that will appear in the
// IPv6 packet.
ipv6Header = new Ipv6Header();
// We definitely know the destination IPv6 address but the stack will
// choose the "appropriate" local v6 interface depending on the
// routing table which may be different than the address we bound
// the socket to. Because of this we will call the Winsock ioctl
// SIO_ROUTING_INTERFACE_QUERY which will return the local interface
// for a given destination address by querying the routing table.
Console.WriteLine("Implementing the IOControl()...");
pingSocket.IOControl(
WinsockIoctl.SIO_ROUTING_INTERFACE_QUERY,
SockaddrConvert.GetSockaddrBytes(destEndPoint),
localAddressBytes
);
localInterface = SockaddrConvert.GetEndPoint(localAddressBytes);
// Fill out the fields of the IPv6 header used in the pseudo-header checksum calculation
Console.WriteLine("Filling out the IPv6 header fields...");
ipv6Header.SourceAddress = localInterface.Address;
ipv6Header.DestinationAddress = destEndPoint.Address;
ipv6Header.NextHeader = 58; // IPPROTO_ICMP6
// Initialize the ICMPv6 header
Console.WriteLine("Initializing the ICMPv6 header...");
icmpv6Header = new Icmpv6Header(ipv6Header);
icmpv6Header.Type = Icmpv6Header.Icmpv6EchoRequestType;
icmpv6Header.Code = Icmpv6Header.Icmpv6EchoRequestCode;
// Initialize the payload
Console.WriteLine("Initializing the payload...");
pingPayload = new byte[pingPayloadLength];
for (int i = 0; i < pingPayload.Length; i++)
{
pingPayload[i] = (byte)'e';
}
// Create the ICMPv6 echo request header
Console.WriteLine("Creating the ICMPv6 echo request header...");
icmpv6EchoRequestHeader = new Icmpv6EchoRequest();
icmpv6EchoRequestHeader.Id = pingId;
// Add the headers to the protocol header list
Console.WriteLine("Adding the headers to the protocol header list...");
protocolHeaderList.Add(icmpv6Header);
protocolHeaderList.Add(icmpv6EchoRequestHeader);
}
}
