java - HTTP 隧道 Servlet (Java)

Question

我正在尝试编写一个 HTTP 隧道，因为我们希望能够通过我们的 Web 应用程序连接到远程计算机。虽然我知道其中涉及的安全风险，但这是我们愿意做的事情。它不托管在 Internet 上，而是托管在专用网络上，因此风险被认为很低。

基本要求是允许 Java 调试工具通过 servlet 连接到机器。我们有一些客户坚持让开发盒在他们的防火墙一侧，并且由于 java 调试服务器上的返回端口不固定，我们不能简单地要求他们打开一个特定的端口。

代码还不完善。我一直在尝试以双向方式进行通信。

有几个组件。 Eclipse 中的 java 调试连接到的独立服务器。该服务器配置为根据连接的端口知道它的前进方向。因此，如果端口 1166 被命中，它就知道连接到机器 x 上的一个 servlet。

即Eclipse 调试器 --> 调试代理服务器 --> 应用程序 Servlet --> 应用程序 JVM

到目前为止，就我的努力而言，我似乎能够连接，但数据流功能不全。 Eclipse 向 JVM 发送 JDWP-Handshake，JVM 应该用 JDWP-Handshake 回复。我发现当 Eclipse 发送 JDWP-Handshake 时，它​​被写入调试代理服务器，然后中继到 Servlet，但看起来这在 servlet 中被忽略了。我收到的日志如下:

[INFO] Started Jetty Server
2012-06-18 10:00:53,356  INFO ProxySocket  - Connection received, forwarding to tidevwls03:1166 via http://localhost:8080/tunnel/debug-proxy
2012-06-18 10:00:53,361  INFO ProxySocket  - Connected to http://localhost:8080/tunnel/debug-proxy
2012-06-18 10:00:53,603  INFO ProxyServlet  - Received incoming http connection, attempting to forward to endpoint tidevwls03:1166
2012-06-18 10:00:53,604  INFO ProxyServlet  - Connecting to endpoint tidevwls03:1166
2012-06-18 10:00:53,613  INFO StreamProxy  - [endpoint-read -> http-write    ] beginning proxy transport.
2012-06-18 10:00:53,613  INFO StreamProxy  - [http-read     -> endpoint-write] beginning proxy transport.
2012-06-18 10:00:53,619  INFO ProxySocket  - Response Header: HTTP/1.1 200 OK
2012-06-18 10:00:53,619  INFO ProxySocket  - Response Header: Content-Length: 0
2012-06-18 10:00:53,623  INFO ProxySocket  - Response Header: Server: Jetty(6.1.22)
2012-06-18 10:00:53,624  INFO StreamProxy  - [client-read  -> servlet-write  ] beginning proxy transport.
2012-06-18 10:00:53,624  INFO StreamProxy  - [client-read  -> servlet-write  ] 'J'
2012-06-18 10:00:53,624  INFO StreamProxy  - [servlet-read -> client-write   ] beginning proxy transport.
2012-06-18 10:00:53,624  INFO StreamProxy  - [client-read  -> servlet-write  ] 'D'
2012-06-18 10:00:53,624  INFO StreamProxy  - [client-read  -> servlet-write  ] 'W'
2012-06-18 10:00:53,624  INFO StreamProxy  - [client-read  -> servlet-write  ] 'P'
2012-06-18 10:00:53,624  INFO StreamProxy  - [client-read  -> servlet-write  ] '-'
2012-06-18 10:00:53,624  INFO StreamProxy  - [client-read  -> servlet-write  ] 'H'
2012-06-18 10:00:53,624  INFO StreamProxy  - [client-read  -> servlet-write  ] 'a'
2012-06-18 10:00:53,624  INFO StreamProxy  - [client-read  -> servlet-write  ] 'n'
2012-06-18 10:00:53,624  INFO StreamProxy  - [client-read  -> servlet-write  ] 'd'
2012-06-18 10:00:53,624  INFO StreamProxy  - [client-read  -> servlet-write  ] 's'
2012-06-18 10:00:53,624  INFO StreamProxy  - [client-read  -> servlet-write  ] 'h'
2012-06-18 10:00:53,624  INFO StreamProxy  - [client-read  -> servlet-write  ] 'a'
2012-06-18 10:00:53,625  INFO StreamProxy  - [client-read  -> servlet-write  ] 'k'
2012-06-18 10:00:53,625  INFO StreamProxy  - [client-read  -> servlet-write  ] 'e'

我想知道我是否需要改变我对此的想法，以便将流分解为多个请求并使用基于 session 的连接。一个请求将成为一个永无止境的下游(即无限响应)，然后当客户端发送到 servlet 时，它会每次创建一个新请求。这是让它正常工作的关键吗？

下面是调试代理服务器的代码，它可以独立运行，或者我临时将其配置为在 Jetty 服务器上作为 servlet 运行，以便快速测试周转时间。 (ProxySocket.java)

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.net.ServerSocket;
import java.net.Socket;
import java.net.URL;
import java.util.List;

import javax.net.SocketFactory;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;

import org.apache.commons.io.IOUtils;
import org.apache.commons.lang.StringUtils;
import org.apache.log4j.Logger;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class ProxySocket extends HttpServlet {
  private static final Logger logger = Logger.getLogger( ProxySocket.class ); 
  private static final ApplicationContext springContext = new ClassPathXmlApplicationContext( "env-spring/applicationContext*.xml" ); 

  @Override
  public void init() throws ServletException {
    List<HttpDebugConfig> configs = ( List<HttpDebugConfig> ) springContext.getBean( "DebugProxyHosts" );
    for ( HttpDebugConfig config : configs ) {
      ProxyServer proxyServer = new ProxyServer( config );
      proxyServer.start();
    }
  }

  class ProxyServer extends Thread {
    private HttpDebugConfig config;

    public ProxyServer( HttpDebugConfig config ) {
      this.config = config;
    }

    public void run() {
      ServerSocket ss = null;
      StreamProxy streamToTunnel = null;
      StreamProxy streamToClient = null;

      try {
        ss = new ServerSocket( config.getLocalPort() );
        Socket inbound = null;
        Socket outbound = null;
        logger.info( String.format( "Listening for connections on port %d. Proxying to %s:%d", config.getLocalPort(), config.getRemoteHost(), config.getRemotePort() ) );
        while ( ( inbound = ss.accept() ) != null ) {
          try {
            logger.info( String.format( "Connection received, forwarding to %s:%d via %s", config.getRemoteHost(), config.getRemotePort(), config.getProxyUrl() ) );

            URL proxy = new URL( config.getProxyUrl() );

            outbound = SocketFactory.getDefault().createSocket( proxy.getHost(), proxy.getPort() );
            logger.info( String.format( "Connected to %s", config.getProxyUrl() ) );

            OutputStream out = outbound.getOutputStream();
            BufferedReader in = new BufferedReader( new InputStreamReader( outbound.getInputStream() ) );

            writeLine( out, String.format( "POST %s HTTP/1.1", config.getProxyUrl() ) );
            writeLine( out, String.format( "Host: http://%s:%s", proxy.getHost(), proxy.getPort() ) );
            writeLine( out, "Connection: keep-alive" );
            writeLine( out, String.format( "tunnel_host: %s", config.getRemoteHost() ) );
            writeLine( out, String.format( "tunnel_port: %s", String.valueOf( config.getRemotePort() ) ) );
            writeLine( out, "" );

            // read the http response and then we can start tunnelling.
            for ( String line = ""; StringUtils.isNotBlank( line = in.readLine() ); ) {
              logger.info( String.format( "Response Header: %s", line ) );
            }

            streamToTunnel = new StreamProxy( "[client-read  -> servlet-write  ]", inbound.getInputStream(), outbound.getOutputStream() );
            streamToClient = new StreamProxy( "[servlet-read -> client-write   ]", outbound.getInputStream(), inbound.getOutputStream() );
            streamToTunnel.start();
            streamToClient.start();

            while ( streamToClient.isAlive() || streamToTunnel.isAlive() ) {
              try { Thread.sleep( 100 ); } catch ( InterruptedException e ) { }
            }

            logger.info( String.format( "Shutting down socket-to-%s.", config.getProxyUrl() ) );
          } finally {
            IOUtils.closeQuietly( inbound );
            IOUtils.closeQuietly( outbound );
          }
        }
      } catch ( IOException e ) {
        logger.error( String.format( "No longer listening for connections on port %d. Proxying to %s:%d", config.getLocalPort(), config.getRemoteHost(), config.getRemotePort() ), e );
      } finally {
        if ( ss != null ) {
          try { ss.close(); } catch ( Exception e ) { }
        }
      }
    }

    private void writeLine( OutputStream out, String msg ) throws IOException {
      out.write( String.format( "%s\n", StringUtils.defaultString( msg ) ).getBytes() );
    }
  }
}

下一段代码是spring配置(/env-spring/applicationContext.xml)。

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
    xmlns:util="http://www.springframework.org/schema/util"
    xsi:schemaLocation="
        http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.1.xsd 
        http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-3.1.xsd
    ">
    <util:list id="DebugProxyHosts" list-class="java.util.ArrayList">
        <bean class="HttpDebugConfig">
            <property name="localPort" value="1166" />
            <property name="proxyUrl" value="http://localhost:8080/tunnel/debug-proxy" />
            <property name="remoteHost" value="tidevwls03" />
            <property name="remotePort" value="1166" />
        </bean> 
    </util:list>
</beans>

配置 bean (HttpDebugConfig.java)。

public class HttpDebugConfig {
  private int localPort;
  private String remoteHost;
  private int remotePort;
  private String proxyUrl;

  public int getLocalPort() {
    return localPort;
  }

  public void setLocalPort( int localPort ) {
    this.localPort = localPort;
  }

  public String getRemoteHost() {
    return remoteHost;
  }

  public void setRemoteHost( String remoteHost ) {
    this.remoteHost = remoteHost;
  }

  public int getRemotePort() {
    return remotePort;
  }

  public void setRemotePort( int remotePort ) {
    this.remotePort = remotePort;
  }

  public String getProxyUrl() {
    return proxyUrl;
  }

  public void setProxyUrl( String proxyUrl ) {
    this.proxyUrl = proxyUrl;
  }
}

输入流到输出流的复制器(StreamProxy.java)

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

import org.apache.commons.io.IOUtils;
import org.apache.log4j.Logger;

public class StreamProxy extends Thread {
  private static final Logger logger = Logger.getLogger( StreamProxy.class );

  private InputStream in;
  private OutputStream out;

  private boolean kill = false;

  public StreamProxy( String name, InputStream in, OutputStream out ) {
    this.in = in;
    this.out = out;
    setName( name );
  }

  @Override
  public void interrupt() {
    this.kill = true;
    super.interrupt();
  }

  @Override
  public void run() {
    try {
      logger.info( String.format( "%s beginning proxy transport.", getName() ) );
      do {
        int n = 0;
        while ( -1 != ( n = in.read() ) ) {
          logger.info( getName() + " '" + ( char ) n + "'" );
          out.write( n );
          // out.flush();
        }
        try { Thread.sleep( 1 ); } catch ( Exception e ) { }
      } while ( ! kill );
      logger.info( String.format( "%s completed proxy transport.", getName() ) );
    } catch ( IOException e ) {
      logger.error( String.format( "%s Failed to copy from input stream to output stream. Aborting thread.", getName() ),  e );
      kill = true;
    } finally {
      IOUtils.closeQuietly( in );
      IOUtils.closeQuietly( out );
    }
  }
}

这部分是Tunnel Servlet (ProxyServlet.java)

import java.io.IOException;
import java.net.Socket;

import javax.net.SocketFactory;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.io.IOUtils;
import org.apache.commons.lang.StringUtils;
import org.apache.commons.lang.math.NumberUtils;
import org.apache.log4j.Logger;

public class ProxyServlet extends HttpServlet {
  private static final Logger logger = Logger.getLogger( ProxyServlet.class ); 
  private static final long serialVersionUID = -686421490573011755L;

  @Override
  protected void service( HttpServletRequest request, HttpServletResponse response ) throws ServletException, IOException {
    new Runner( request, response ).start();
  }

  class Runner extends Thread {
    private HttpServletRequest request;
    private HttpServletResponse response;

    public Runner( HttpServletRequest request, HttpServletResponse response ) {
      this.request = request;
      this.response = response;
    }

    @Override
    public void run() {
      Socket endpoint = null;
      StreamProxy streamToHttp = null;
      StreamProxy streamToEndpoint = null;

      String host = StringUtils.defaultIfEmpty( request.getHeader( "tunnel_host" ), "localhost" );
      int port = NumberUtils.toInt( request.getHeader( "tunnel_port" ), 8000 );

      try {
        logger.info( String.format( "Received incoming http connection, attempting to forward to endpoint %s:%d", host, port ) );

        logger.info( String.format( "Connecting to endpoint %s:%d", host, port ) );
        endpoint = SocketFactory.getDefault().createSocket( host, port );

        streamToHttp = new StreamProxy( "[endpoint-read -> http-write    ]", endpoint.getInputStream(), response.getOutputStream() );
        streamToEndpoint = new StreamProxy( "[http-read     -> endpoint-write]", request.getInputStream(), endpoint.getOutputStream() );
        streamToHttp.start();
        streamToEndpoint.start();

        while ( streamToEndpoint.isAlive() || streamToHttp.isAlive() ) {
          try { Thread.sleep( 100 ); } catch ( InterruptedException e ) { }
        }

        logger.info( String.format( "Safely shut down servlet-to-%s:%d proxy.", host, port ) );
      } catch ( IOException e ) {
        logger.error( String.format( "Shutting down servlet-to-%s:%d proxy.", host, port ), e );
      } finally {
        if ( streamToHttp != null ) {
          streamToHttp.interrupt();
        }
        if ( streamToEndpoint != null ) {
          streamToEndpoint.interrupt();
        }
        IOUtils.closeQuietly( endpoint );
      }
    }
  }
}

应用容器配置(web.xml)

<?xml version="1.0" encoding="ISO-8859-1"?>
<web-app xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"
    version="2.4">

    <display-name>tunnel</display-name>

    <context-param>
        <param-name>log4jConfigLocation</param-name>
        <param-value>classpath:log4j.properties
        </param-value>
    </context-param>

    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>classpath:env-spring/applicationContext*.xml</param-value>
    </context-param>

    <listener>
        <listener-class>org.springframework.web.util.Log4jConfigListener</listener-class>
    </listener>

    <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>

    <servlet>
        <servlet-name>Debug Proxy</servlet-name>
        <servlet-class>ProxyServlet</servlet-class>
        <load-on-startup>1</load-on-startup>
    </servlet>

    <servlet-mapping>
        <servlet-name>Debug Proxy</servlet-name>
        <url-pattern>/debug-proxy</url-pattern>
    </servlet-mapping>

    <servlet>
        <servlet-name>Debug Socket</servlet-name>
        <servlet-class>ProxySocket</servlet-class>
        <load-on-startup>1</load-on-startup>
    </servlet>

    <servlet-mapping>
        <servlet-name>Debug Socket</servlet-name>
        <url-pattern>/debug-socket</url-pattern>
    </servlet-mapping>

    <welcome-file-list>
        <welcome-file>index.jsp</welcome-file>
    </welcome-file-list>
</web-app>

最后，我正在使用 maven 构建的 pom.xml。

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>tunnel</groupId>
  <artifactId>tunnel</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <packaging>war</packaging>

    <properties>
        <version.spring>3.1.1.RELEASE</version.spring>
    </properties>

    <build>
        <plugins>
            <plugin>
                <groupId>org.mortbay.jetty</groupId>
                <artifactId>maven-jetty-plugin</artifactId>
                <version>6.1.22</version>
                <configuration>
                    <webApp>${project.build.directory}/${project.build.finalName}.${project.packaging}</webApp>
                    <stopPort>9966</stopPort>
                    <stopKey>foo</stopKey>
                </configuration>
            </plugin>
        </plugins>
    </build>

    <dependencies>
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>servlet-api</artifactId>
            <version>2.5</version>
        </dependency>

        <!-- Utilities -->
        <dependency>
            <groupId>commons-lang</groupId>
            <artifactId>commons-lang</artifactId>
            <version>2.6</version>
        </dependency>
        <dependency>
            <groupId>commons-io</groupId>
            <artifactId>commons-io</artifactId>
            <version>2.0.1</version>
        </dependency>
        <dependency>
            <groupId>commons-collections</groupId>
            <artifactId>commons-collections</artifactId>
            <version>3.2.1</version>
        </dependency>
        <dependency>
            <groupId>commons-logging</groupId>
            <artifactId>commons-logging</artifactId>
            <version>1.1.1</version>
        </dependency>
        <dependency>
            <groupId>commons-httpclient</groupId>
            <artifactId>commons-httpclient</artifactId>
            <version>3.0.1</version>
            <exclusions>
                <exclusion>
                    <artifactId>junit</artifactId>
                    <groupId>junit</groupId>
                </exclusion>
            </exclusions>
        </dependency>
        <dependency>
            <groupId>commons-codec</groupId>
            <artifactId>commons-codec</artifactId>
            <version>1.2</version>
        </dependency>

        <!-- Logging -->
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.16</version>
        </dependency>

        <!-- Spring Framework -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-core</artifactId>
            <version>${version.spring}</version>
        </dependency>
    <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>${version.spring}</version>
        </dependency>
    <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-web</artifactId>
            <version>${version.spring}</version>
        </dependency>
    <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>${version.spring}</version>
        </dependency>
    </dependencies> 
</project>

我使用以下 Maven 目标运行 Jetty 服务器

jetty:stop clean install jetty:run-war

希望您觉得这个小项目很有趣!我期待听到您的想法和意见。

谢谢，斯图尔特

Answer 1

SSH 隧道 - 我的选择 http://en.wikipedia.org/wiki/Tunneling_protocol

ssh -L [bind_address:]port:sshserverhostname:targetmachinehostname port

-L 指定将本地(客户端)主机上的给定端口转发到给定主机 和远程端的端口。这通过分配一个套接字来监听本地端口来工作 端，可选地绑定(bind)到指定的 bind_address。每当连接到此 端口，连接通过安全通道转发，并与主机建立连接 来自远程机器的端口主机端口。端口转发也可以在配置中指定 口粮文件。可以通过将地址括在方括号中来指定 IPv6 地址。 只有 super 用户可以转发特权端口。默认情况下，本地端口绑定(bind)在accor- 与 GatewayPorts 设置共舞。但是，可以使用显式 bind_address 来绑定(bind) 连接到特定地址。 `localhost'' 的 bind_address 表示 listen-
ing 端口仅供本地使用，而空地址或 *' 表示该端口 应该可以从所有界面访问。