BadVPN is an open-source peer-to-peer VPN system. It provides a Layer 2 (Ethernet) network between the peers (VPN nodes). The peers connect to a central server which acts as a chat server for them to establish direct connections between each other (data connections). These connections are used for transferring network data (Ethernet frames), and can be secured with a multitude of mechanisms.

Features

• UDP and TCP transport
• Converges very quickly after a new peer joins
• IGMP snooping to deliver multicasts efficiently (e.g. for IPTV)
• Features related to the NAT problem:
  1. Can work with multiple layers of NAT (needs configuration)
  2. Local peers inside a NAT can communicate directly
  3. Relaying as a fallback (needs configuration)

Requirements

BadVPN is written in the C programming language and currently works on Linux and Windows.

Installation

A Gentoo Linux ebuild is available in the Downloads section, and a package for Arch Linux is available in the AUR, named “badvpn”. A Windows build is available too. If you want to build BadVPN from source, see INSTALL.

Documentation

Documentation is available on the wiki:

• badvpn – General description of BadVPN and its features.
• Examples – Quick guide to setting up a working VPN.
• badvpn_server, badvpn_client – Documentation of individual programs.

Design

BadVPN programs are fully event-driven. BadVPN has a flow-based design: the complete application is constructed from a large set of small independent I/O modules which exchange data through predefined interfaces. Furthermore, it is based on an original programming paradigm (the job queue paradigm), which greatly simplifies developing I/O modules. You can read more about the job queue paradigm at http://code.google.com/p/badvpn/source/detail?r=58 .

NCD

NCD, the Network Configuration Daemon, is a daemon and programming language for configuration of network interfaces and other aspects of the operating system. It implements various functionalities as built-in modules, which may then be called from a NCD program wherever and for whatever purpose the user needs them. This modularity makes NCD extremely flexible and extensible. It does a very good job with hotplugging in various forms, like USB network interfaces and link detection for wired devices. NCD is capable of configuring BadVPN virtual interfaces.

tun2socks

Aside from the BadVPN client and server programs, the package also contain the tun2socks program. This program is used to “socksify” TCP connections at the network layer. It implements a TUN device which accepts all incoming TCP connections (regardless of destination IP), and forwards the connections through a SOCKS server. This allows you to forward all connections through SOCKS, without any need for application support. It can be used, for example, to forward connections through a remote SSH server.

See the tun2socks wiki page for more info.

License

BadVPN is Copyright (C) 2010 Ambroz Bizjak.

BadVPN is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License version 2 as published by the Free Software Foundation.

BadVPN is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

项目地址：http://code.google.com/p/badvpn/

下载地址：http://code.google.com/p/badvpn/downloads/list

本文原始地址：http://igfw.net/archives/2663