public static int verifyMessage(byte[] data, int len, bool verbose)
{
long calced_cksum = 0;
if (len < MINIMUM_VERIFIABLE_MSG_LEN)
{
return(-1); // too small to be a verifiable msg
}
calced_cksum = VerifiableMessage.inet_cksum(data, len);
if (verbose)
{
System.Console.WriteLine("Calculated cksum = " + calced_cksum);
}
if (calced_cksum == 0)
{
return(1); // success
}
for (int i = 0; i < 4; i++)
{
if (data[i + 2] != MAGIC_NUMBER[i])
{
return(-1); // no magic number found, not a verifiable message - failed
}
}
return(0); // magic number found, but bad checksum - failed
}
public static byte[] constructVerifiableMessage(int len)
{
// bytes 0 and 1 are for the checksum
// bytes 2 through 5 are for the 4 byte magic number
// remaining bytes are generated randomly
byte[] message = new byte[len];
long cksum;
Array.Copy(MAGIC_NUMBER, 0, message, 2, 4);
for (int i = 6; i < len; i++)
{
message[i] = (byte)(GENERATOR.Next() & 0xff);
}
cksum = VerifiableMessage.inet_cksum(message, len);
message[0] = (byte)((cksum >> 8) & 0xff);
message[1] = (byte)(cksum & 0xff);
return(message);
}