public override void HandleHandshakeMessage(HandshakeType handshakeMessageType, ReadableBuffer buffer, ref WritableBuffer outBuffer)
{
switch (State)
{
case StateType.None:
if (handshakeMessageType != HandshakeType.client_hello)
{
Alerts.AlertException.ThrowAlert(Alerts.AlertLevel.Fatal, Alerts.AlertDescription.unexpected_message, "Tls 12 didnt get a client hello");
}
Hello.ReadClientHelloTls12(buffer, this);
if (CipherSuite == null)
{
//Couldn't agree a set of ciphers
Alerts.AlertException.ThrowAlert(Alerts.AlertLevel.Fatal, Alerts.AlertDescription.handshake_failure, "Could not agree on a cipher suite during reading client hello");
}
this.StartHandshakeHash(buffer);
//Write server hello
ChangeState(StateType.SendServerHello);
_frameWriter.StartFrame(RecordType.Handshake, ref outBuffer);
this.WriteHandshake(ref outBuffer, HandshakeType.server_hello, Hello.SendServerHello12);
_frameWriter.FinishFrame(ref outBuffer);
_frameWriter.StartFrame(RecordType.Handshake, ref outBuffer);
this.WriteHandshake(ref outBuffer, HandshakeType.certificate, ServerHandshakeTls12.SendCertificates);
_frameWriter.FinishFrame(ref outBuffer);
if (CipherSuite.ExchangeType == KeyExchangeType.Ecdhe || CipherSuite.ExchangeType == KeyExchangeType.Dhe)
{
if (KeyShare == null)
{
KeyShare = CryptoProvider.GetDefaultKeyShare(CipherSuite.ExchangeType);
}
_frameWriter.StartFrame(RecordType.Handshake, ref outBuffer);
this.WriteHandshake(ref outBuffer, HandshakeType.server_key_exchange, ServerHandshakeTls12.SendKeyExchange);
_frameWriter.FinishFrame(ref outBuffer);
}
_frameWriter.StartFrame(RecordType.Handshake, ref outBuffer);
this.WriteHandshake(ref outBuffer, HandshakeType.server_hello_done, (w, state) => w);
_frameWriter.FinishFrame(ref outBuffer);
ChangeState(StateType.WaitClientKeyExchange);
break;
case StateType.WaitClientKeyExchange:
if (handshakeMessageType != HandshakeType.client_key_exchange)
{
Alerts.AlertException.ThrowAlert(Alerts.AlertLevel.Fatal, Alerts.AlertDescription.unexpected_message, $"Received a {handshakeMessageType} when we expected a {HandshakeType.client_key_exchange}");
}
HandshakeHash.HashData(buffer);
KeyShare.SetPeerKey(buffer.Slice(5));
_schedule.GenerateMasterSecret();
_schedule.CalculateClientFinished();
//We can send the server finished because we have the expected client finished
_schedule.GenerateKeyMaterial();
ChangeState(StateType.ChangeCipherSpec);
break;
case StateType.WaitClientFinished:
if (handshakeMessageType != HandshakeType.finished)
{
Alerts.AlertException.ThrowAlert(Alerts.AlertLevel.Fatal, Alerts.AlertDescription.unexpected_message, $"unexpected message");
}
_schedule.CompareClientFinishedGenerateServerFinished(buffer);
_frameWriter.StartFrame(RecordType.ChangeCipherSpec, ref outBuffer);
outBuffer.WriteBigEndian <byte>(1);
_frameWriter.FinishFrame(ref outBuffer);
_writeKey = _schedule.GetServerKey();
_frameWriter.StartFrame(RecordType.Handshake, ref outBuffer);
this.WriteHandshake(ref outBuffer, HandshakeType.finished, _schedule.WriteServerFinished);
_frameWriter.FinishFrame(ref outBuffer);
KeyShare?.Dispose();
KeyShare = null;
ChangeState(StateType.HandshakeComplete);
break;
default:
Alerts.AlertException.ThrowAlert(Alerts.AlertLevel.Fatal, Alerts.AlertDescription.unexpected_message, $"Not in any known state {State} that we expected a handshake messge from {handshakeMessageType}");
break;
}
}