WinDivert 2.2: Windows Packet Divert

1. Introduction

Windows Packet Divert (WinDivert) is a user-mode packet interception library for Windows 7, Windows 8 and Windows 10.

WinDivert enables user-mode capturing/modifying/dropping of network packets sent to/from the Windows network stack. In summary, WinDivert can: - capture network packets - filter/drop network packets - sniff network packets - (re)inject network packets - modify network packets WinDivert can be used to implement user-mode packet filters, sniffers, firewalls, NATs, VPNs, IDSs, tunneling applications, etc..

WinDivert supports the following features: - packet interception, sniffing, or dropping modes - support for loopback (localhost) traffic - full IPv6 support - network layer - simple yet powerful API - high-level filtering language - filter priorities - freely available under the terms of the GNU Lesser General Public License (LGPLv3)

For more information see doc/windivert.html

2. Architecture

The basic architecture of WinDivert is as follows:

                          +-----------------+
                          |                 |
                 +------->|    PROGRAM      |--------+
                 |        | (WinDivert.dll) |        |
                 |        +-----------------+        |
                 |                                   | (3) re-injected
                 | (2a) matching packet              |     packet
                 |                                   |
                 |                                   |

[user mode] | | ....................|...................................|................... [kernel mode] | | | | | | +---------------+ +-----------------> (1) packet | | (2b) non-matching packet ------------>| WinDivert.sys |--------------------------------------------> | | +---------------+

The WinDivert.sys driver is installed below the Windows network stack. The following actions occur:

(1) A new packet enters the network stack and is intercepted by WinDivert.sys (2a) If the packet matches the PROGRAM-defined filter, it is diverted. The PROGRAM can then read the packet using a call to WinDivertRecv(). (2b) If the packet does not match the filter, the packet continues as normal. (3) PROGRAM either drops, modifies, or re-injects the packet. PROGRAM can re-inject the (modified) using a call to WinDivertSend().

3. License

WinDivert is dual-licensed under your choice of the GNU Lesser General Public License (LGPL) Version 3 or the GNU General Public License (GPL) Version 2. See the LICENSE file for more information.

4. About

WinDivert was written by basil.

For further information, or bug reports, please contact:

[email protected]

The homepage for WinDivert is:

https://reqrypt.org/windivert.html

The source code for WinDivert is hosted by GitHub at:

https://github.com/basil00/Divert