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POFast implementation of a port forward in Java
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copied!<p>I have build a simple application that opens a ServerSocket, and on connection, it connects itself to another server socket on a remote machine. To implement port forwarding, I use two threads, one that reads from the local inputstream and streams to the remote sockets outputstream, and vice versa.</p> <p>The implementation feels a bit inperformant, and so I ask you if you know a better implementation strategy, or even have some code lying around to achive this in a performant way.</p> <p>PS: I know I could use IPTables on Linux, but this has to work on Windows.</p> <p>PPS: If you post implementations for this simple task, I will create a benchmark to test all given implementations. The solution should be fast for many small (~100bytes) packages and steady data streams.</p> <p>My current implementation is this (executed on each of the two threads for each direction):</p> <pre><code>public static void route(InputStream inputStream, OutputStream outputStream) throws IOException { byte[] buffer = new byte[65536]; while( true ) { // Read one byte to block int b = inputStream.read(); if( b == - 1 ) { log.info("No data available anymore. Closing stream."); inputStream.close(); outputStream.close(); return; } buffer[0] = (byte)b; // Read remaining available bytes b = inputStream.read(buffer, 1, Math.min(inputStream.available(), 65535)); if( b == - 1 ) { log.info("No data available anymore. Closing stream."); inputStream.close(); outputStream.close(); return; } outputStream.write(buffer, 0, b+1); } } </code></pre>

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