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Difference between revisions of "Jetty/Feature/NPN"

< Jetty‎ | Feature
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The Jetty project provides an implementation of the [http://technotes.googlecode.com/git/nextprotoneg.html Next Protocol Negotiation TLS Extension] (NPN) for OpenJDK 7 or greater.
 
The Jetty project provides an implementation of the [http://technotes.googlecode.com/git/nextprotoneg.html Next Protocol Negotiation TLS Extension] (NPN) for OpenJDK 7 or greater.
 +
NPN is a Transport Layer Security (TLS) extension for application layer protocol negotiation. It allows the application layer to negotiate which protocol to use over the secure connection.
  
Jetty's NPN implementation, although hosted under the umbrella of the Jetty project, is independent of Jetty (the Servlet Container), and can be reused in any other Java network server.
+
NPN currently negotiates using SPDY as an application level protocol on port 443, and also negotiates the SPDY version. However, NPN is not SPDY specific in any way.
 +
Jetty's NPN implementation, although hosted under the umbrella of the Jetty project, is independent of Jetty (the servlet container); you can use it in any other Java network server.
  
| body =
+
===JVM Startup Use===
  
===JVM Startup Usage===
+
To enable NPN support, you need to start the JVM with:
 
+
In order to enable NPN support, you need to start the JVM with:
+
  
 
<source lang="bash">
 
<source lang="bash">
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</source>
 
</source>
  
where <code>path_to_npn_boot_jar</code> is the path on file system for the NPN Boot jar file, for example one at the following Maven coordinates [http://repo2.maven.org/maven2/org/mortbay/jetty/npn/npn-boot org.mortbay.jetty.npn:npn-boot].
+
where <code>path_to_npn_boot_jar</code> is the path on the file system for the NPN Boot jar file, for example one at the following Maven coordinates [http://repo2.maven.org/maven2/org/mortbay/jetty/npn/npn-boot org.mortbay.jetty.npn:npn-boot].
  
===API Usage===
+
===API Use===
  
Applications needs to interact with the negotiation of the next protocol performed by the NPN TLS extension. For example, server applications need to know whether the client supports NPN, and client applications needs to know the list of protocols supported by the server, and so on.
+
Applications needs to interact with NPN TLS extension protocol negotiations. For example, server applications need to know whether the client supports NPN, and client applications needs to know the list of protocols supported by the server, and so on.
  
In order to provide this interaction, Jetty's NPN implementation provides an API to applications, hosted at Maven coordinates <code>org.eclipse.jetty.npn:npn-api</code>.
+
To provide this interaction, Jetty's NPN implementation provides an API to applications, hosted at Maven coordinates <code>org.eclipse.jetty.npn:npn-api</code>.
This dependency needs to be declared as "provided", because it is already included in the <code>npn-boot</code> jar (see section above) and therefore will be available in the boot classpath.
+
You need to declare this dependency ''provided'', because the <code>npn-boot</code> jar already includes it (see the previous section above) and it is therefore available in the boot classpath.
  
The API is composed of a single class, <code>org.eclipse.jetty.npn.NextProtoNego</code>, and applications need to register instances of <code>SSLSocket</code> or <code>SSLEngine</code> with a <code>ClientProvider</code> or <code>ServerProvider</code> (depending on whether the application is a client or server application).
+
The API consists of a single class, <code>org.eclipse.jetty.npn.NextProtoNego</code>, and applications need to register instances of <code>SSLSocket</code> or <code>SSLEngine</code> with a <code>ClientProvider</code> or <code>ServerProvider</code> (depending on whether the application is a client or server application).
 
Refer to [http://download.eclipse.org/jetty/stable-7/apidocs/org/eclipse/jetty/npn/NextProtoNego.html <code>NextProtoNego</code> javadocs] and to the examples below for further details about client and server provider methods.
 
Refer to [http://download.eclipse.org/jetty/stable-7/apidocs/org/eclipse/jetty/npn/NextProtoNego.html <code>NextProtoNego</code> javadocs] and to the examples below for further details about client and server provider methods.
  
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</source>
 
</source>
  
The <code>NextProtoNego.ClientProvider</code> methods <code>supports()</code>, <code>unsupported()</code> and <code>selectProtocol(List&lt;String&gt;)</code> will be called by the NPN implementation, so that the client application can, respectively, decide whether to support NPN, whether the server supports NPN, and select one of the protocols supported by the server.
+
TheNPN implementation calls <code>NextProtoNego.ClientProvider</code> methods <code>supports()</code>, <code>unsupported()</code> and <code>selectProtocol(List&lt;String&gt;)</code>, so that the client application can decide:
 +
* whether to support NPN.
 +
* whether the server supports NPN.
 +
* to select one of the protocols the server supports.
  
 
The example for <code>SSLEngine</code> is identical, and you just need to replace the <code>SSLSocket</code> instance with a <code>SSLEngine</code> instance.
 
The example for <code>SSLEngine</code> is identical, and you just need to replace the <code>SSLSocket</code> instance with a <code>SSLEngine</code> instance.
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</source>
 
</source>
  
The <code>NextProtoNego.ServerProvider</code> methods <code>unsupported()</code>, <code>protocols()</code> and <code>protocolSelected(String)</code> will be called by the NPN implementation, so that the server application can, respectively, know whether the client supports NPN, provide the list of protocols supported by the server, and know what is the protocol chosen by the client.
+
The NPN implementation calls <code>NextProtoNego.ServerProvider</code> methods <code>unsupported()</code>, <code>protocols()</code> and <code>protocolSelected(String)</code>, so that the server application can
 +
* know whether the client supports NPN.
 +
* provide the list of protocols the server suports.
 +
* know which protocol the client chooses.
  
 
===Implementation Details===
 
===Implementation Details===
  
The NPN implementation relies on modification of few OpenJDK classes and on few new classes that needs to live in the <code>sun.security.ssl</code> package.
+
The NPN implementation relies on modification of a few OpenJDK classes and on a few new classes that need to live in the <code>sun.security.ssl</code> package.
 
These classes are released under the same GPLv2+exception license of OpenJDK.
 
These classes are released under the same GPLv2+exception license of OpenJDK.
  
 
The <code>NextProtoNego</code> class is released under same license as the classes of the Jetty project.  
 
The <code>NextProtoNego</code> class is released under same license as the classes of the Jetty project.  
  
===Usage in Unit Tests===
+
===Use in Unit Tests===
  
It is possible to write and run unit tests that make use of the NPN implementation.
+
You can write and run unit tests that use the NPN implementation.
The solution that we used with Maven is to specify an additional command line argument to the Surefire plugin:
+
The solution that we use with Maven is to specify an additional command line argument to the Surefire plugin:
  
 
<source lang="xml">
 
<source lang="xml">
Line 127: Line 133:
 
===Debugging===
 
===Debugging===
  
Debug logging for the NPN implementation can be enabled in this way:
+
You can enable debug logging for the NPN implementation in this way:
  
 
<source lang="java">
 
<source lang="java">
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</source>
 
</source>
  
Since the <code>NextProtoNego</code> class is in the boot classpath, we chose to not use logging libraries in order to not override application's logging library choices, so the logging is performed directly on <code>System.err</code>.
+
Since the <code>NextProtoNego</code> class is in the boot classpath, we chose not to use logging libraries because we do not want to override application logging library choices; therefore the logging is performed directly on <code>System.err</code>.
  
 
}}
 
}}

Revision as of 15:30, 12 March 2012



Introduction

The Jetty project provides an implementation of the Next Protocol Negotiation TLS Extension (NPN) for OpenJDK 7 or greater. NPN is a Transport Layer Security (TLS) extension for application layer protocol negotiation. It allows the application layer to negotiate which protocol to use over the secure connection.

NPN currently negotiates using SPDY as an application level protocol on port 443, and also negotiates the SPDY version. However, NPN is not SPDY specific in any way. Jetty's NPN implementation, although hosted under the umbrella of the Jetty project, is independent of Jetty (the servlet container); you can use it in any other Java network server.

JVM Startup Use

To enable NPN support, you need to start the JVM with:

java -Xbootclasspath/p:<path_to_npn_boot_jar> ...

where path_to_npn_boot_jar is the path on the file system for the NPN Boot jar file, for example one at the following Maven coordinates org.mortbay.jetty.npn:npn-boot.

API Use

Applications needs to interact with NPN TLS extension protocol negotiations. For example, server applications need to know whether the client supports NPN, and client applications needs to know the list of protocols supported by the server, and so on.

To provide this interaction, Jetty's NPN implementation provides an API to applications, hosted at Maven coordinates org.eclipse.jetty.npn:npn-api. You need to declare this dependency provided, because the npn-boot jar already includes it (see the previous section above) and it is therefore available in the boot classpath.

The API consists of a single class, org.eclipse.jetty.npn.NextProtoNego, and applications need to register instances of SSLSocket or SSLEngine with a ClientProvider or ServerProvider (depending on whether the application is a client or server application). Refer to NextProtoNego javadocs and to the examples below for further details about client and server provider methods.

Client Example

SSLContext sslContext = ...;
SSLSocket sslSocket = (SSLSocket)context.getSocketFactory()
        .createSocket("localhost", server.getLocalPort());
 
NextProtoNego.put(sslSocket, new NextProtoNego.ClientProvider()
{
    @Override
    public boolean supports()
    {
        return true;
    }
 
    @Override
    public void unsupported()
    {
    }
 
    @Override
    public String selectProtocol(List<String> protocols)
    {
        return protocols.get(0);
    }
});

TheNPN implementation calls NextProtoNego.ClientProvider methods supports(), unsupported() and selectProtocol(List<String>), so that the client application can decide:

  • whether to support NPN.
  • whether the server supports NPN.
  • to select one of the protocols the server supports.

The example for SSLEngine is identical, and you just need to replace the SSLSocket instance with a SSLEngine instance.

Server Example

SSLSocket sslSocket = ...;
NextProtoNego.put(sslSocket, new NextProtoNego.ServerProvider()
{
    @Override
    public void unsupported()
    {
    }
 
    @Override
    public List<String> protocols()
    {
        return Arrays.asList("http/1.1");
    }
 
    @Override
    public void protocolSelected(String protocol)
    {
        System.out.println("Protocol Selected is: " + protocol);
    }
});

The NPN implementation calls NextProtoNego.ServerProvider methods unsupported(), protocols() and protocolSelected(String), so that the server application can

  • know whether the client supports NPN.
  • provide the list of protocols the server suports.
  • know which protocol the client chooses.

Implementation Details

The NPN implementation relies on modification of a few OpenJDK classes and on a few new classes that need to live in the sun.security.ssl package. These classes are released under the same GPLv2+exception license of OpenJDK.

The NextProtoNego class is released under same license as the classes of the Jetty project.

Use in Unit Tests

You can write and run unit tests that use the NPN implementation. The solution that we use with Maven is to specify an additional command line argument to the Surefire plugin:

<project ...>
 
  <properties>
    <npn-version>7.6.2.v20120308</npn-version>
  </properties>
 
  <build>
    <plugins>
      <plugin>
        <artifactId>maven-surefire-plugin</artifactId>
        <configuration>
          <argLine>-Xbootclasspath/p:${settings.localRepository}/org/mortbay/jetty/npn/npn-boot/${npn-version}/npn-boot-${npn-version}.jar</argLine>
        </configuration>
      </plugin>
 
      ...
 
    </plugins>
  </build>
 
  ...
 
</project>

Debugging

You can enable debug logging for the NPN implementation in this way:

NextProtoNego.debug = true;

Since the NextProtoNego class is in the boot classpath, we chose not to use logging libraries because we do not want to override application logging library choices; therefore the logging is performed directly on System.err.

Feature

{{{body}}}