Oligocast

Introduction

Welcome to "oligocast," a test tool for multicast networking. Oligocast can send and receive UDP packets on multicast groups. It's similar to "mtools", but with some enhancements:

• source filtering (including source specific multicast)
• IPv4 and IPv6 in the same program
• send and receive from the same program (by default)

It's meant for use from the Linux command line and similar environments.

Status

Oligocast is open source, free to use and redistribute under a BSD-type license.

Oligocast has been tested and found to work on Linux. It's got problems on macOS with source filtering, and hasn't been tested at all on *BSD.

Using

To use oligocast:

• Get the sources: git clone https://github.com/Jaxartes/oligocast
• If you're building for an unusual platform you may have to edit the file "oligocast_config.h". On recent Linux you shouldn't need to.
• Build with "make".
• To send packets: Use the "-t" option.
• To receive packets: Use the "-r" option.
• In both cases, also use "-g" to specify the multicast group and "-i" for the network interface name.

Examples:

• oligocast -tiwlan0 -g224.2.2.2
• oligocast -r -iwlan0 -gff15::33
• oligocast -rviotn3v1 -le32 -gff15::ff -Efd96:1::3,fd96:1::2

Other comments

What's in the name? It's a play on words. In "multicast", "multi-" means "many." "Oligo-" means "few."

If you run "oligocast" as "oligosend" (perhaps through a symlink) it will only send and you won't need the "-t" option. Likewise "oligorecv".

Source filtering is specified with the "-I" and "-E" options. It can be changed on the fly, by using the "-k" option and then passing new "-I" and "-E" on standard input.

TODO

There is much to be done on this project:

• Write the documentation for this program: see oligocast.manual.txt.
• Once a manual page is written, trim down usage(), which is way too long, down to just a list of options.
• Fix source filtering on macOS.
• Test and get working on *BSD.
• Go through the code for places errthrottle() should be used.
• Maybe #ifdef all the IPv6-specific code, for building on systems where IPv6 multicast is missing or badly broken. Maybe do so for IPv4 too.
• Potential feature: When receiving a packet, report the source address. Perhaps other details like length, contents.
• Potential feature: Make "-i" optional, having it pick an interface for itself if none is specified.