/**
* Initiates a TLS handshake in the role of client.<br/>
* <br/>
* In blocking mode, this will not return until the handshake is complete.
* In non-blocking mode, use {@link TlsPeer#NotifyHandshakeComplete()} to
* receive a callback when the handshake is complete.
*
* @param tlsClient The {@link TlsClient} to use for the handshake.
* @throws IOException If in blocking mode and handshake was not successful.
*/
public virtual void Connect(TlsClient tlsClient)
{
if (tlsClient == null)
{
throw new ArgumentNullException("tlsClient");
}
if (this.mTlsClient != null)
{
throw new InvalidOperationException("'Connect' can only be called once");
}
this.mTlsClient = tlsClient;
base.LoggingContext = this.mTlsClient.LoggingContext;
if (HTTPManager.Logger.Level <= Loglevels.All)
{
HTTPManager.Logger.Verbose("TlsClientProtocol", "Connect", this.LoggingContext);
}
this.mSecurityParameters = new SecurityParameters();
this.mSecurityParameters.entity = ConnectionEnd.client;
this.mTlsClientContext = new TlsClientContextImpl(mSecureRandom, mSecurityParameters);
this.mTlsClientContext.UserObject = this.LoggingContext;
this.mSecurityParameters.clientRandom = CreateRandomBlock(tlsClient.ShouldUseGmtUnixTime(),
mTlsClientContext.NonceRandomGenerator);
this.mTlsClient.Init(mTlsClientContext);
this.mRecordStream.Init(mTlsClientContext);
tlsClient.NotifyCloseHandle(this);
TlsSession sessionToResume = tlsClient.GetSessionToResume();
if (sessionToResume != null && sessionToResume.IsResumable)
{
SessionParameters sessionParameters = sessionToResume.ExportSessionParameters();
if (sessionParameters != null && sessionParameters.IsExtendedMasterSecret)
{
this.mTlsSession = sessionToResume;
this.mSessionParameters = sessionParameters;
}
}
SendClientHelloMessage();
this.mConnectionState = CS_CLIENT_HELLO;
BlockForHandshake();
}
protected virtual void ReportServerVersion(ClientHandshakeState state, ProtocolVersion server_version)
{
TlsClientContextImpl clientContext = state.clientContext;
ProtocolVersion currentServerVersion = clientContext.ServerVersion;
if (null == currentServerVersion)
{
clientContext.SetServerVersion(server_version);
state.client.NotifyServerVersion(server_version);
}
else if (!currentServerVersion.Equals(server_version))
{
throw new TlsFatalAlert(AlertDescription.illegal_parameter);
}
}
protected virtual byte[] GenerateClientHello(ClientHandshakeState state, TlsClient client)
{
ProtocolVersion client_version = client.ClientVersion;
if (!client_version.IsDtls)
{
throw new TlsFatalAlert(AlertDescription.internal_error);
}
TlsClientContextImpl context = state.clientContext;
context.SetClientVersion(client_version);
SecurityParameters securityParameters = context.SecurityParameters;
// Session ID
byte[] session_id = TlsUtilities.EmptyBytes;
if (state.tlsSession != null)
{
session_id = state.tlsSession.SessionID;
if (session_id == null || session_id.Length > 32)
{
session_id = TlsUtilities.EmptyBytes;
}
}
bool fallback = client.IsFallback;
state.offeredCipherSuites = client.GetCipherSuites();
if (session_id.Length > 0 && state.sessionParameters != null)
{
if (!state.sessionParameters.IsExtendedMasterSecret ||
!Arrays.Contains(state.offeredCipherSuites, state.sessionParameters.CipherSuite) ||
CompressionMethod.cls_null != state.sessionParameters.CompressionAlgorithm)
{
session_id = TlsUtilities.EmptyBytes;
}
}
state.clientExtensions = TlsExtensionsUtilities.EnsureExtensionsInitialised(client.GetClientExtensions());
TlsExtensionsUtilities.AddExtendedMasterSecretExtension(state.clientExtensions);
MemoryStream buf = new MemoryStream();
TlsUtilities.WriteVersion(client_version, buf);
buf.Write(securityParameters.ClientRandom, 0, securityParameters.ClientRandom.Length);
TlsUtilities.WriteOpaque8(session_id, buf);
// Cookie
TlsUtilities.WriteOpaque8(TlsUtilities.EmptyBytes, buf);
// Cipher Suites (and SCSV)
{
/*
* RFC 5746 3.4. The client MUST include either an empty "renegotiation_info" extension,
* or the TLS_EMPTY_RENEGOTIATION_INFO_SCSV signaling cipher suite value in the
* ClientHello. Including both is NOT RECOMMENDED.
*/
byte[] renegExtData = TlsUtilities.GetExtensionData(state.clientExtensions, ExtensionType.renegotiation_info);
bool noRenegExt = (null == renegExtData);
bool noRenegSCSV = !Arrays.Contains(state.offeredCipherSuites, CipherSuite.TLS_EMPTY_RENEGOTIATION_INFO_SCSV);
if (noRenegExt && noRenegSCSV)
{
// TODO Consider whether to default to a client extension instead
state.offeredCipherSuites = Arrays.Append(state.offeredCipherSuites, CipherSuite.TLS_EMPTY_RENEGOTIATION_INFO_SCSV);
}
/*
* RFC 7507 4. If a client sends a ClientHello.client_version containing a lower value
* than the latest (highest-valued) version supported by the client, it SHOULD include
* the TLS_FALLBACK_SCSV cipher suite value in ClientHello.cipher_suites [..]. (The
* client SHOULD put TLS_FALLBACK_SCSV after all cipher suites that it actually intends
* to negotiate.)
*/
if (fallback && !Arrays.Contains(state.offeredCipherSuites, CipherSuite.TLS_FALLBACK_SCSV))
{
state.offeredCipherSuites = Arrays.Append(state.offeredCipherSuites, CipherSuite.TLS_FALLBACK_SCSV);
}
TlsUtilities.WriteUint16ArrayWithUint16Length(state.offeredCipherSuites, buf);
}
TlsUtilities.WriteUint8ArrayWithUint8Length(new byte[] { CompressionMethod.cls_null }, buf);
TlsProtocol.WriteExtensions(buf, state.clientExtensions);
return(buf.ToArray());
}