content: /*
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements.  See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership.  The ASF licenses this file
   * to you under the Apache License, Version 2.0 (the
   * "License"); you may not use this file except in compliance
   * with the License.  You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package org.apache.cassandra.transport;
  
  import java.security.cert.Certificate;
  import javax.net.ssl.SSLPeerUnverifiedException;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import io.netty.channel.Channel;
  import com.codahale.metrics.Counter;
  import io.netty.handler.ssl.SslHandler;
  import org.apache.cassandra.auth.IAuthenticator;
  import org.apache.cassandra.config.DatabaseDescriptor;
  import org.apache.cassandra.service.ClientState;
  import org.apache.cassandra.service.QueryState;
  
  public class ServerConnection extends Connection
  {
      private static final Logger logger = LoggerFactory.getLogger(ServerConnection.class);
  
      private volatile IAuthenticator.SaslNegotiator saslNegotiator;
      private final ClientState clientState;
      private volatile ConnectionStage stage;
      public final Counter requests = new Counter();
  
      ServerConnection(Channel channel, ProtocolVersion version, Connection.Tracker tracker)
      {
          super(channel, version, tracker);
  
          clientState = ClientState.forExternalCalls(channel.remoteAddress());
          stage = ConnectionStage.ESTABLISHED;
      }
  
      public ClientState getClientState()
      {
          return clientState;
      }
  
      ConnectionStage stage()
      {
          return stage;
      }
  
      QueryState validateNewMessage(Message.Type type, ProtocolVersion version)
      {
          switch (stage)
          {
              case ESTABLISHED:
                  if (type != Message.Type.STARTUP && type != Message.Type.OPTIONS)
                      throw new ProtocolException(String.format("Unexpected message %s, expecting STARTUP or OPTIONS", type));
                  break;
              case AUTHENTICATING:
                  // Support both SASL auth from protocol v2 and the older style Credentials auth from v1
                  if (type != Message.Type.AUTH_RESPONSE && type != Message.Type.CREDENTIALS)
                      throw new ProtocolException(String.format("Unexpected message %s, expecting %s", type, version == ProtocolVersion.V1 ? "CREDENTIALS" : "SASL_RESPONSE"));
                  break;
              case READY:
                  if (type == Message.Type.STARTUP)
                      throw new ProtocolException("Unexpected message STARTUP, the connection is already initialized");
                  break;
              default:
                  throw new AssertionError();
          }
  
          return new QueryState(clientState);
      }
  
      void applyStateTransition(Message.Type requestType, Message.Type responseType)
      {
          switch (stage)
          {
              case ESTABLISHED:
                  if (requestType == Message.Type.STARTUP)
                  {
                      if (responseType == Message.Type.AUTHENTICATE)
                          stage = ConnectionStage.AUTHENTICATING;
                      else if (responseType == Message.Type.READY)
                          stage = ConnectionStage.READY;
                  }
                  break;
              case AUTHENTICATING:
                  // Support both SASL auth from protocol v2 and the older style Credentials auth from v1
                  assert requestType == Message.Type.AUTH_RESPONSE || requestType == Message.Type.CREDENTIALS;
  
                  if (responseType == Message.Type.READY || responseType == Message.Type.AUTH_SUCCESS)
                  {
                      stage = ConnectionStage.READY;
                      // we won't use the authenticator again, null it so that it can be GC'd
                      saslNegotiator = null;
                  }
                  break;
              case READY:
                  break;
              default:
                  throw new AssertionError();
          }
      }
  
      public IAuthenticator.SaslNegotiator getSaslNegotiator(QueryState queryState)
      {
          if (saslNegotiator == null)
              saslNegotiator = DatabaseDescriptor.getAuthenticator()
                                                 .newSaslNegotiator(queryState.getClientAddress(), certificates());
          return saslNegotiator;
      }
  
      private Certificate[] certificates()
      {
          SslHandler sslHandler = (SslHandler) channel().pipeline()
                                                        .get("ssl");
          Certificate[] certificates = null;
  
          if (sslHandler != null)
          {
              try
              {
                  certificates = sslHandler.engine()
                                           .getSession()
                                           .getPeerCertificates();
              }
              catch (SSLPeerUnverifiedException e)
              {
                  if (logger.isTraceEnabled())
                      logger.trace("Failed to get peer certificates for peer {}", channel().remoteAddress(), e);
              }
          }
          return certificates;
      }
  
      /**
       * @return Whether this connection is SSL-encrypted.
       */
      public boolean isSSL()
      {
          // If an SslHandler is present on the pipeline, the connection is using ssl.
          SslHandler sslHandler = (SslHandler) channel().pipeline()
                                                        .get("ssl");
          return sslHandler != null;
      }
  }
  