Question

我正在通过SSLSocketFactory编写一个简单的HTTP服务器，这是我的Java代码：

 public static void main(String[] args) throws Exception {
      KeyStore ks = KeyStore.getInstance("PKCS12");
      ks.load(TestEcho.class.getResourceAsStream("/localhost.pfx"),
              "****".toCharArray());
      KeyManagerFactory kmf = KeyManagerFactory.getInstance("SunX509");
      kmf.init(ks, "****".toCharArray());
      SSLContext sslc = SSLContext.getInstance("TLS");
      sslc.init(kmf.getKeyManagers(), null, null);

      // try (ServerSocket server = new ServerSocket(4443)) {
      try (ServerSocket server = sslc.getServerSocketFactory().createServerSocket(4443)) {
           while (true) {
                Socket socket = server.accept();
                // ((SSLSocket) socket).getSession();
                socket.getInputStream().read();
                socket.getOutputStream().write("HTTP/1.1 200 OK\r\nContent-Length: 2\r\nConnection: close\r\n\r\nok".getBytes());
                socket.getOutputStream().flush();
           }
      }
 }

但性能远低于Tomcat Http11Protocol（bio）。我捕获TCP转储并在服务器端ChangeCipherSpec和Finished之间找到100 + ms的差距。但是当我连接到Tomcat时，没有这样的差距。

上述代码的TCP转储是：

[127.0.0.1:1962 Connected at 00:58:21.718]
[127.0.0.1:1962 Sent at 00:58:21.718] // ClientHello
0000:0000  16 03 03 00 C3 01 00 00-BF 03 03 59 82 04 AD 44   ...........Y...D
...
0000:00C0  02 03 02 01 02 02 01 01                           ........        
[127.0.0.1:1962 Received at 00:58:21.781] // ServerHello & Certificate & ServerHelloDone
0000:0000  16 03 03 0B EB 02 00 00-4D 03 03 59 82 04 A8 14   ........M..Y....
...
0000:0BE0  12 0D 53 CB B6 20 64 BC-8E 77 3A 0F 0E 00 00 00   ..S.. d..w:.....
[127.0.0.1:1962 Sent at 00:58:21.812] // ClientKeyExchange
0000:0000  16 03 03 00 46 10 00 00-42 41 04 ED DD 67 FB 22   ....F...BA...g."
...
0000:0040  39 50 1F 50 F2 12 62 A7-3D C8 FE                  9P.P..b.=..     
[127.0.0.1:1962 Sent at 00:58:21.828] // Client ChangeCipherSpec
0000:0000  14 03 03 00 01 01                                 ......          
[127.0.0.1:1962 Sent at 00:58:21.828]  // Client Finished
0000:0000  16 03 03 00 50 8E DB DC-39 07 9B 68 36 17 BB 44   ....P...9..h6..D
...
0000:0050  B3 5E 91 FF E8                                    .^...           
[127.0.0.1:1962 Received at 00:58:21.890] // Server ChangeCipherSuite
0000:0000  14 03 03 00 01 01                                 ......          
[127.0.0.1:1962 Received at 00:58:22.046] // Server Finished, but delayed 156ms !!!
0000:0000  16 03 03 00 50 71 68 70-ED 8F D6 73 11 94 DD F4   ....Pqhp...s....
0000:0010  D9 A4 1F 60 BA 48 43 B0-4B 53 EF 66 E5 59 F2 8B   ...`.HC.KS.f.Y..
0000:0020  DD CE D7 D5 8F C4 68 A2-87 07 92 A9 3B D9 9B 3B   ......h.....;..;
0000:0030  DD DE 1A 71 6F 87 8D 59-17 6F 8F 94 2C 89 01 DA   ...qo..Y.o..,...
0000:0040  E9 7D 08 E2 F2 FC 54 BF-FA 8D 45 F8 7B B0 29 8D   .}....T...E.{.).
0000:0050  CE 87 CF 81 E1                                    .....           
[127.0.0.1:1962 Sent at 00:58:22.046] // HTTP Request
0000:0000  17 03 03 00 A0 73 85 EE-93 BC 66 94 76 6D 49 74   .....s....f.vmIt
...
0000:00A0  DE C2 BE DD 46                                    ....F           
[127.0.0.1:1962 Received at 00:58:22.062] // HTTP Response
0000:0000  17 03 03 02 70 E8 CF 13-B4 E0 4F 32 8E 6F 37 74   ....p.....O2.o7t
...
0000:0270  DD 5B FB 99 9D                                    .[...           
[127.0.0.1:1962 Sent at 00:58:22.062] // Disconnect
0000:0000  15 03 03 00 40 42 BC E5-B7 B2 E4 B5 22 D2 DF 75   ....@B......"..u
...
0000:0040  B8 59 B2 89 FB                                    .Y...           
[127.0.0.1:1962 Disconnected at 00:58:22.062]

在对Tomcat服务器的测试中，TCP转储类似于：

...
[127.0.0.1:1968 Received at 00:58:50.312] // server-side ChangeCipherSpec & Finished
0000:0000  14 03 03 00 01 01 16 03-03 00 50 03 0D D0 FE 94   ..........P.....
0000:0010  5D 0B 22 60 62 46 F3 29-D9 37 B7 D1 42 60 5A 6A   ]."`bF.).7..B`Zj
0000:0020  93 C8 1F CF D8 B9 81 7D-DD 3D A9 1E A0 F0 C0 05   .......}.=......
0000:0030  11 C8 C4 B9 31 16 E5 1E-2F 43 EA 45 2A F0 E8 BF   ....1.../C.E*...
0000:0040  9E BD 20 84 8E 5A 1A 57-0B 31 32 BE 5E 6C B3 F3   .. ..Z.W.12.^l..
0000:0050  6A 00 95 D3 75 32 03 35-83 3D 12                  j...u2.5.=.     
...

我的Java代码中是否存在SSLContext，KeyManagers或SSL握手的使用问题？

Answer 1

在阅读tomcat的源代码后，我只需启用 TCP_NODELAY 即可删除延迟：

                Socket socket = server.accept();
                socket.setTcpNoDelay(true);
                // ((SSLSocket) socket).getSession();

<强> UPDATE-1

并且tomcat为每个接受的套接字启用TCP_NODELAY。请参阅tomcat-coyote的源代码（8.0.x）org.apache.tomcat.util.net.SocketProperties第155行：

/**
 * TCP_NO_DELAY option. JVM default used if not set.
 */
protected Boolean tcpNoDelay = Boolean.TRUE;

和2个setProperties方法，一旦套接字被调用就被调用。

<强> UPDATE-2

JVM默认禁用TCP_NODELAY，这意味着 Nagle的算法可以延迟发送小字节。显然， Server Finished 被Nagle的算法延迟了。

有关 TCP_NODELAY 的大量文章可以用Google搜索。

SSL握手：为什么服务器端在服务器端ChangeCipherSpec和Finished之间等待100+ ms？

1 个答案: