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UDP Broadcast Packet Relay

This program listens for packets on a specified UDP broadcast port. When a packet is received, it sends that packet to all specified interfaces but the one it came from as though it originated from the original sender.

The primary purpose of this is to allow games on machines on separated local networks (Ethernet, WLAN) that use udp broadcasts to find each other to do so.

It also works on ppp links, so you can log in from windows boxes (e.g. using pptp) and play LAN-based games together. Currently, you have to care about upcoming or downgoing interfaces yourself.

INSTALL

make ; cp udp-broadcast-relay /some/where

USAGE

/some/where/udp-broadcast-relay id udp-port eth0 eth1...

udp-broadcast-relay must be run as boot to be able to create a raw socket (necessary) to send packets as though they originated from the original sender.

COMPATIBILITY

I run debian woody with Linux 2.4.20, and here it works.

EXAMPLE

/some/where/udp-broadcast-relay -f 1 6112 eth0 eth1 # forward Warcraft 3 broadcast packets

AVAILABLE PATCHES

Since I currently do not use udp-broadcast-relay, I can not test submitted patches and other files, but I will share them here. You can find the files in the download directory.

Patrick Huesmann submitted a patch to make udp-broadcast-relay send the packes to those NICs it did not recieve it from, based on the actual socket, not the broadcast IP. This is useful if more than one physical networks share the same broadcast range.
Савченко В. М. submitted an ip-up.local an ip-down.local file to automatically restart udp-broadcast-relay when new ppp-interfaces come up.

Thanks to all contributors!

BUGS/CRITICISM/PATCHES/ETC

web: http://www.joachim-breitner.de/udp_broadcast_relay/
e-mail: Joachim Breitner <mail@joachim-breitner.de>

HISTORY

0.3 2003-09-28: Sending packets also to ppp addresses
0.2 2003-09-18: Flags for debugging and forking, Compilefixes, Makefile-Target "clean"
0.1 2003-09-15: Initial rewrite of udp_broadcast_fw

CREDITS

This is based upon udp_broadcast_fw:
Web: http://www.serverquery.com/udp_broadcast_fw/
Email: Nathan O'Sullivan

HISTORY of udp_broadcast_fw

0.1.1 - 19 Feb 02: Moved fork() code to just before main loop so that errors would appear
0.1 - 18 Feb 02: Initial release

LICENSE

This code is made available under the GPL. Read the COPYING file inside the archive for more info.