pygmp - Multicast Routing in Linux

Python interface and services for Linux multicast routing.

Limitations / Roadmap

This is a work in progress. Currently, only IPv4 multicast routing is supported. The software has only been tested on Ubuntu 20.04, and is not garenteed to work on other distros. The only implementation thus far is a simple, IPv4, static multicast router with a REST API.

Quick Start

Install the library with all dependencies needed to run router services.

pip install py-gmp[daemons]

IPv4 Static Multicast Routing

Setup the simple daemon's config file. The default location for the file is at /etc/simple.ini.

For example, say I have two network interfaces: eth0 and br0. I'd like route all incoming multicast for groups 239.1.0.1/24 on the eth device to the bridge. The config file would look like this.

[phyints]
names=eth0,br0

[mroute_1]
from = eth0
group = 239.1.0.1/24
to = br0

Next, start the daemon.

sudo python3 -m pygmp simple

Developer Quick Start

Install the task utility. This utility is used to standardize build and test processes.

task install

Test

task test

IPv4 Static Multicast Routing

Run an example simple multicast router in a network namespace.

task run

In your browser, you should be able to hit http://172.20.0.2:8000/docs to see the OpenAPI documentation.

Roadmap

• finalize IPv4 simple multicast daemon implementation
• Improve CI/CD / versioning process / testing / setup readthedocs
• MLD/IPv6 support
• Containerized example
• pimd daemon implementation

Host Configuration Gotchas

Most new Linux distibutions set the IGMP version to 3. To test with IGMPv2, you'll need to set it to 2 and reboot. Also, make sure mc_forwarding is enabled. Change the values in /etc/sysctl.conf. Then, reboot.

net.ipv4.ip_forward = 1
net.ipv4.conf.all.force_igmp_version = 2
net.ipv4.conf.default.force_igmp_version = 2
net.ipv4.conf.all.mc_forwarding = 1
net.ipv4.conf.default.mc_forwarding = 1