public void TestChecksums()
{
IPPacket.IPVersions[] versions = { IPPacket.IPVersions.IPv4, IPPacket.IPVersions.IPv6 };
for (int i = 0; i < 10000; i++)
{
int len;
//choose random version
IPPacket.IPVersions ipver = versions[Rand.Instance.GetInt(0, 1)];
//choose random len based on version
if (ipver == IPPacket.IPVersions.IPv4)
{
len = Rand.Instance.GetInt(54, 1500);
}
else
{
len = Rand.Instance.GetInt(74, 1500);
}
TCPPacket tcp = TCPPacket.RandomPacket(len, ipver);
//TODO: this test should use a known quantity, a packet recorded and loaded from a file
Assert.AreEqual(len, tcp.Bytes.Length);
Assert.IsTrue(tcp.ValidIPChecksum);
Assert.IsTrue(tcp.ValidTCPChecksum);
}
}
/// <summary> Extract the protocol code from packet data. The packet data
/// must contain an IP datagram.
/// The protocol code specifies what kind of information is contained in the
/// data block of the ip datagram.
///
/// </summary>
/// <param name="lLen">the length of the link-level header.
/// </param>
/// <param name="packetBytes">packet bytes, including the link-layer header.
/// </param>
/// <returns> the IP protocol code. i.e. 0x06 signifies TCP protocol.
/// </returns>
public static int extractProtocol(int lLen, byte[] packetBytes)
{
IPPacket.IPVersions ipVer = ExtractVersion(lLen, packetBytes);
int protoOffset;
switch (ipVer)
{
case IPPacket.IPVersions.IPv4:
protoOffset = IPv4Fields_Fields.IP_CODE_POS;
break;
case IPPacket.IPVersions.IPv6:
protoOffset = IPv6Fields_Fields.NEXT_HEADER_POS;
break;
default:
return(-1); //unknown ip version
}
return(packetBytes[lLen + protoOffset]);
}
