private static byte[] createTLSClientHello(String hostname, SslProtocols protocol)
{
ByteBuffer buffer = new ByteBuffer();
//build our byte array backwards
buffer.Append(buildNPNExtension());
buffer.Append(buildSNIRecord(hostname));
//for now, now ALPN extension
//buffer.Append(buildALPNExtension());
//prepend the length of the extensions
buffer.Prepend(toInt16(buffer.Size));
//1 compression option, which is null compression
buffer.PrependHex("0100");
//our ciphers
buffer.PrependHex("cc14cc13cc15c02bc02f009ec00ac0140039c009c0130033009c0035002f000a00ff");
//cipher length
buffer.Prepend(toInt16(34));
//SessionID len = 0
buffer.Prepend(0x00);
//prepend random
buffer.Prepend(buildRandomBytes());
buffer.Prepend(buildDateTimeBytes());
//TLS 1.2 marker
if (protocol == SslProtocols.Tls12)
{
buffer.PrependHex("0303");
}
else if (protocol == SslProtocols.Tls11)
{
buffer.PrependHex("0302");
}
else if (protocol == SslProtocols.Tls)
{
buffer.PrependHex("0301");
}
else
{
buffer.PrependHex("0300");
}
//length so far
buffer.Prepend(toInt16(buffer.Size));
//record type and 00 for the first byte of the size (stupid uint24s)
buffer.PrependHex("0100");
//size again
buffer.Prepend(toInt16(buffer.Size));
//outer record
if (protocol == SslProtocols.Ssl3)
{
buffer.PrependHex(removeWhitespace("16 03 00"));
}
else
{
buffer.PrependHex(removeWhitespace("16 03 01"));
}
return buffer.ToByteArray();
}
/// <summary>
/// Read all the bytes from a stream
/// </summary>
private static byte[] ReadAllBytes(Stream stream)
{
ByteBuffer byteBuffer = new ByteBuffer();
try
{
byte[] buffer = new byte[8192];
int bytesRead = 0;
while ((bytesRead = stream.Read(buffer, 0, buffer.Length)) > 0)
{
//append them to our byte buffer
byteBuffer.Append(buffer, bytesRead);
}
}
catch (Exception)
{
byteBuffer = null;
}
return (byteBuffer != null) ? byteBuffer.ToByteArray() : null;
}
/// <summary>
/// Builds the SNI extension bytes for a hostname (SNI is the length of the hostname + 9 bytes)
/// </summary>
protected static byte[] buildSNIRecord(string hostname)
{
byte[] asciiHost = System.Text.Encoding.ASCII.GetBytes(hostname);
ByteBuffer buffer = new ByteBuffer();
//0x0000 to tell that is an SNI extension
buffer.AppendHex(removeWhitespace("00 00"));
buffer.Append(toInt16(asciiHost.Length + 5));
buffer.Append(toInt16(asciiHost.Length + 3));
buffer.AppendHex("00");
buffer.Append(toInt16(asciiHost.Length));
buffer.Append(asciiHost);
return buffer.ToByteArray();
}
