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1   /*
2    * Copyright 2014 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    *   https://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.channel.epoll;
17  
18  import io.netty.buffer.ByteBuf;
19  import io.netty.channel.Channel;
20  import io.netty.channel.ChannelException;
21  import io.netty.channel.ChannelOutboundBuffer;
22  import io.netty.channel.socket.InternetProtocolFamily;
23  import io.netty.channel.socket.ServerSocketChannel;
24  import io.netty.channel.socket.SocketChannel;
25  import io.netty.util.concurrent.GlobalEventExecutor;
26  
27  import java.io.IOException;
28  import java.net.InetAddress;
29  import java.net.InetSocketAddress;
30  import java.net.SocketAddress;
31  import java.util.Collection;
32  import java.util.Collections;
33  import java.util.Map;
34  import java.util.concurrent.Executor;
35  
36  import static io.netty.channel.epoll.LinuxSocket.newSocketStream;
37  import static io.netty.channel.epoll.Native.IS_SUPPORTING_TCP_FASTOPEN_CLIENT;
38  
39  /**
40   * {@link SocketChannel} implementation that uses linux EPOLL Edge-Triggered Mode for
41   * maximal performance.
42   */
43  public final class EpollSocketChannel extends AbstractEpollStreamChannel implements SocketChannel {
44  
45      private final EpollSocketChannelConfig config;
46  
47      private volatile Collection<InetAddress> tcpMd5SigAddresses = Collections.emptyList();
48  
49      public EpollSocketChannel() {
50          super(newSocketStream(), false);
51          config = new EpollSocketChannelConfig(this);
52      }
53  
54      public EpollSocketChannel(InternetProtocolFamily protocol) {
55          super(newSocketStream(protocol), false);
56          config = new EpollSocketChannelConfig(this);
57      }
58  
59      public EpollSocketChannel(int fd) {
60          super(fd);
61          config = new EpollSocketChannelConfig(this);
62      }
63  
64      EpollSocketChannel(LinuxSocket fd, boolean active) {
65          super(fd, active);
66          config = new EpollSocketChannelConfig(this);
67      }
68  
69      EpollSocketChannel(Channel parent, LinuxSocket fd, InetSocketAddress remoteAddress) {
70          super(parent, fd, remoteAddress);
71          config = new EpollSocketChannelConfig(this);
72  
73          if (parent instanceof EpollServerSocketChannel) {
74              tcpMd5SigAddresses = ((EpollServerSocketChannel) parent).tcpMd5SigAddresses();
75          }
76      }
77  
78      /**
79       * Returns the {@code TCP_INFO} for the current socket.
80       * See <a href="https://linux.die.net//man/7/tcp">man 7 tcp</a>.
81       */
82      public EpollTcpInfo tcpInfo() {
83          return tcpInfo(new EpollTcpInfo());
84      }
85  
86      /**
87       * Updates and returns the {@code TCP_INFO} for the current socket.
88       * See <a href="https://linux.die.net//man/7/tcp">man 7 tcp</a>.
89       */
90      public EpollTcpInfo tcpInfo(EpollTcpInfo info) {
91          try {
92              socket.getTcpInfo(info);
93              return info;
94          } catch (IOException e) {
95              throw new ChannelException(e);
96          }
97      }
98  
99      @Override
100     public InetSocketAddress remoteAddress() {
101         return (InetSocketAddress) super.remoteAddress();
102     }
103 
104     @Override
105     public InetSocketAddress localAddress() {
106         return (InetSocketAddress) super.localAddress();
107     }
108 
109     @Override
110     public EpollSocketChannelConfig config() {
111         return config;
112     }
113 
114     @Override
115     public ServerSocketChannel parent() {
116         return (ServerSocketChannel) super.parent();
117     }
118 
119     @Override
120     protected AbstractEpollUnsafe newUnsafe() {
121         return new EpollSocketChannelUnsafe();
122     }
123 
124     @Override
125     boolean doConnect0(SocketAddress remote) throws Exception {
126         if (IS_SUPPORTING_TCP_FASTOPEN_CLIENT && config.isTcpFastOpenConnect()) {
127             ChannelOutboundBuffer outbound = unsafe().outboundBuffer();
128             outbound.addFlush();
129             Object curr;
130             if ((curr = outbound.current()) instanceof ByteBuf) {
131                 ByteBuf initialData = (ByteBuf) curr;
132                 // If no cookie is present, the write fails with EINPROGRESS and this call basically
133                 // becomes a normal async connect. All writes will be sent normally afterwards.
134                 long localFlushedAmount = doWriteOrSendBytes(
135                         initialData, (InetSocketAddress) remote, true);
136                 if (localFlushedAmount > 0) {
137                     // We had a cookie and our fast-open proceeded. Remove written data
138                     // then continue with normal TCP operation.
139                     outbound.removeBytes(localFlushedAmount);
140                     return true;
141                 }
142             }
143         }
144         return super.doConnect0(remote);
145     }
146 
147     private final class EpollSocketChannelUnsafe extends EpollStreamUnsafe {
148         @Override
149         protected Executor prepareToClose() {
150             try {
151                 // Check isOpen() first as otherwise it will throw a RuntimeException
152                 // when call getSoLinger() as the fd is not valid anymore.
153                 if (isOpen() && config().getSoLinger() > 0) {
154                     // We need to cancel this key of the channel so we may not end up in a eventloop spin
155                     // because we try to read or write until the actual close happens which may be later due
156                     // SO_LINGER handling.
157                     // See https://github.com/netty/netty/issues/4449
158                     ((EpollEventLoop) eventLoop()).remove(EpollSocketChannel.this);
159                     return GlobalEventExecutor.INSTANCE;
160                 }
161             } catch (Throwable ignore) {
162                 // Ignore the error as the underlying channel may be closed in the meantime and so
163                 // getSoLinger() may produce an exception. In this case we just return null.
164                 // See https://github.com/netty/netty/issues/4449
165             }
166             return null;
167         }
168     }
169 
170     void setTcpMd5Sig(Map<InetAddress, byte[]> keys) throws IOException {
171         tcpMd5SigAddresses = TcpMd5Util.newTcpMd5Sigs(this, tcpMd5SigAddresses, keys);
172     }
173 }