jdivert

Java bindings for WinDivert, a Windows driver that allows user-mode applications to capture/modify/drop network packets sent to/from the Windows network stack.

Requirements

Java 1.6+
Windows Vista/7/8/10 or Windows Server 2008 (32 or 64 bit)
Administrator Privileges

Installation

Add JDivert as a dependency in your project:

Maven

Put these lines under section dependencies in your pom.xml

<dependency>
  <groupId>com.github.ffalcinelli</groupId>
  <artifactId>jdivert</artifactId>
  <version>1.1</version>
</dependency>

Gradle

In your build.gradle file make sure you include jdivert into dependencies list

repositories {
    mavenCentral()
}

dependencies {
    compile 'com.github.ffalcinelli:jdivert:1.1'
}

JDivert bundles WinDivert 1.1.8 into its JAR file distribution. The first time WinDivertDLL interface gets initialized, it will copy WinDivert .sys and .dll files inside a temporary directory and will point JNA to load them by this directory by setting jna.library.path system property. To have less impact in projects using JNA, the jna.library.path setting is saved before and restored after the WinDivert deployment and load. Upon exit, temporary dir will be removed and so the files in it.

Getting Started

JDivert consists of two main classes: WinDivert and Packet. This follows the PyDivert structure.

First, you usually want to create a WinDivert object to start capturing network traffic and then call .recv() to receive the first Packet that was captured. By receiving packets, they are taken out of the Windows network stack and will not be sent out unless you take action. You can re-inject packets by calling .send(packet). The following example opens a WinDivert handle, receives a single packet, prints it, re-injects it, and then exits:

// Capture only TCP packets to port 80, i.e. HTTP requests.
WinDivert w = new WinDivert("tcp.DstPort == 80 and tcp.PayloadLength > 0");

w.open(); // packets will be captured from now on

Packet packet = w.recv();  // read a single packet
System.out.println(packet);
w.send(packet);  // re-inject the packet into the network stack

w.close();  // stop capturing packets

Packets that are not matched by the "tcp.DstPort == 80 and tcp.PayloadLength > 0" filter will not be handled by WinDivert and continue as usual. The syntax for the filter language is described in the WinDivert documentation.

API Reference Documentation

The API Reference Documentation for JDivert can be found here.

ffalcinelli / jdivert