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1   /*
2    * Copyright 2017 The Netty Project
3    *
4    * The Netty Project licenses this file to you under the Apache License,
5    * version 2.0 (the "License"); you may not use this file except in compliance
6    * with the License. You may obtain a copy of the License at:
7    *
8    *   http://www.apache.org/licenses/LICENSE-2.0
9    *
10   * Unless required by applicable law or agreed to in writing, software
11   * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
12   * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
13   * License for the specific language governing permissions and limitations
14   * under the License.
15   */
16  package io.netty.handler.ssl;
17  
18  import io.netty.buffer.ByteBuf;
19  import io.netty.buffer.ByteBufAllocator;
20  import io.netty.channel.ChannelHandler;
21  import io.netty.channel.ChannelHandlerContext;
22  import io.netty.handler.codec.ByteToMessageDecoder;
23  import io.netty.util.ReferenceCountUtil;
24  import io.netty.util.internal.ObjectUtil;
25  
26  import javax.net.ssl.SSLContext;
27  import javax.net.ssl.SSLParameters;
28  import java.util.List;
29  
30  /**
31   * {@link OptionalSslHandler} is a utility decoder to support both SSL and non-SSL handlers
32   * based on the first message received.
33   */
34  public class OptionalSslHandler extends ByteToMessageDecoder {
35  
36      private final SslContext sslContext;
37  
38      public OptionalSslHandler(SslContext sslContext) {
39          this.sslContext = ObjectUtil.checkNotNull(sslContext, "sslContext");
40      }
41  
42      @Override
43      protected void decode(ChannelHandlerContext context, ByteBuf in, List<Object> out) throws Exception {
44          if (in.readableBytes() < SslUtils.SSL_RECORD_HEADER_LENGTH) {
45              return;
46          }
47          if (SslHandler.isEncrypted(in)) {
48              handleSsl(context);
49          } else {
50              handleNonSsl(context);
51          }
52      }
53  
54      private void handleSsl(ChannelHandlerContext context) {
55          SslHandler sslHandler = null;
56          try {
57              sslHandler = newSslHandler(context, sslContext);
58              context.pipeline().replace(this, newSslHandlerName(), sslHandler);
59              sslHandler = null;
60          } finally {
61              // Since the SslHandler was not inserted into the pipeline the ownership of the SSLEngine was not
62              // transferred to the SslHandler.
63              if (sslHandler != null) {
64                  ReferenceCountUtil.safeRelease(sslHandler.engine());
65              }
66          }
67      }
68  
69      private void handleNonSsl(ChannelHandlerContext context) {
70          ChannelHandler handler = newNonSslHandler(context);
71          if (handler != null) {
72              context.pipeline().replace(this, newNonSslHandlerName(), handler);
73          } else {
74              context.pipeline().remove(this);
75          }
76      }
77  
78      /**
79       * Optionally specify the SSL handler name, this method may return {@code null}.
80       * @return the name of the SSL handler.
81       */
82      protected String newSslHandlerName() {
83          return null;
84      }
85  
86      /**
87       * Override to configure the SslHandler eg. {@link SSLParameters#setEndpointIdentificationAlgorithm(String)}.
88       * The hostname and port is not known by this method so servers may want to override this method and use the
89       * {@link SslContext#newHandler(ByteBufAllocator, String, int)} variant.
90       *
91       * @param context the {@link ChannelHandlerContext} to use.
92       * @param sslContext the {@link SSLContext} to use.
93       * @return the {@link SslHandler} which will replace the {@link OptionalSslHandler} in the pipeline if the
94       * traffic is SSL.
95       */
96      protected SslHandler newSslHandler(ChannelHandlerContext context, SslContext sslContext) {
97          return sslContext.newHandler(context.alloc());
98      }
99  
100     /**
101      * Optionally specify the non-SSL handler name, this method may return {@code null}.
102      * @return the name of the non-SSL handler.
103      */
104     protected String newNonSslHandlerName() {
105         return null;
106     }
107 
108     /**
109      * Override to configure the ChannelHandler.
110      * @param context the {@link ChannelHandlerContext} to use.
111      * @return the {@link ChannelHandler} which will replace the {@link OptionalSslHandler} in the pipeline
112      * or {@code null} to simply remove the {@link OptionalSslHandler} if the traffic is non-SSL.
113      */
114     protected ChannelHandler newNonSslHandler(ChannelHandlerContext context) {
115         return null;
116     }
117 }