public bool TryHandshake(Connection conn, Uri uri)
{
try {
Stream stream = conn.stream;
byte[] keyBuffer = new byte[16];
using (RNGCryptoServiceProvider rng = new RNGCryptoServiceProvider()) {
rng.GetBytes(keyBuffer);
}
string key = Convert.ToBase64String(keyBuffer);
string keySum = key + Constants.HandshakeGUID;
byte[] keySumBytes = Encoding.ASCII.GetBytes(keySum);
Log.Verbose($"Handshake Hashing {Encoding.ASCII.GetString(keySumBytes)}");
byte[] keySumHash = SHA1.Create().ComputeHash(keySumBytes);
string expectedResponse = Convert.ToBase64String(keySumHash);
string handshake =
$"GET /chat HTTP/1.1\r\n" +
$"Host: {uri.Host}:{uri.Port}\r\n" +
$"Upgrade: websocket\r\n" +
$"Connection: Upgrade\r\n" +
$"Sec-WebSocket-Key: {key}\r\n" +
$"Sec-WebSocket-Version: 13\r\n" +
"\r\n";
byte[] encoded = Encoding.ASCII.GetBytes(handshake);
stream.Write(encoded, 0, encoded.Length);
byte[] responseBuffer = new byte[1000];
int?lengthOrNull = ReadHelper.SafeReadTillMatch(stream, responseBuffer, 0, responseBuffer.Length, Constants.endOfHandshake);
if (!lengthOrNull.HasValue)
{
Log.Error("Connected closed before handshake");
return(false);
}
string responseString = Encoding.ASCII.GetString(responseBuffer, 0, lengthOrNull.Value);
string acceptHeader = "Sec-WebSocket-Accept: ";
int startIndex = responseString.IndexOf(acceptHeader) + acceptHeader.Length;
int endIndex = responseString.IndexOf("\r\n", startIndex);
string responseKey = responseString.Substring(startIndex, endIndex - startIndex);
if (responseKey != expectedResponse)
{
Log.Error($"Response key incorrect, Response:{responseKey} Expected:{expectedResponse}");
return(false);
}
return(true);
} catch (Exception e) {
Log.Exception(e);
return(false);
}
}
string ReadToEndForHandshake(Stream stream)
{
using (ArrayBuffer readBuffer = bufferPool.Take(maxHttpHeaderSize)) {
int?readCountOrFail = ReadHelper.SafeReadTillMatch(stream, readBuffer.array, 0, maxHttpHeaderSize, Constants.endOfHandshake);
if (!readCountOrFail.HasValue)
{
return(null);
}
int readCount = readCountOrFail.Value;
string msg = Encoding.ASCII.GetString(readBuffer.array, 0, readCount);
Log.Verbose(msg);
return(msg);
}
}