The Cumulus versions of some packages are not upstream, so to get at the source, getting the source version of the corresponding Debian package is necessary. For example, this is the case with FRR.
Procedure to get source code
- Update package index
apt update
- Get necessary tools
apt install dpkg-dev
- Get desired package source
apt-get source frr
This will dump the source in your current working directory
root@infra:mgmt:~# ls
frr-7.5+cl4.3.0u1 frr_7.5+cl4.3.0u1.dsc frr_7.5+cl4.3.0u1.tar.gz
Which we can verify corresponds to to the FRR version we are running on the switch
root@infra:mgmt:~# vtysh
Hello, this is FRRouting (version 7.5+cl4.3.0u1).
Copyright 1996-2005 Kunihiro Ishiguro, et al.