This repository includes an implementation of netlink for FreeBSD 14.0-CURRENT. The implementation includes netlink, a working rtnetlink for the most critical path, and a half-finished genetlink. Implementation can be easily seen by looking at the pull-request which compares the implementation with the commit that it is based from.
The configuration is meant for netlink to be installed as a module. Instructions assume that the user is starting from a fresh FreeBSD instance. The instance can be obtained from AWS ec2 community marketplace. This repository was configured with FreeBSD14.0-current
- Download this github as
/usr/src - Build and install the kernel
- In
/usr/src/sys/modules/netlink, runmake - Install module created using
make load
A user level netlink library (libmnl) was ported to FreeBSD. Port was needed to change some basic data types and change a few enums. The userlevel library is here: git@github.com:pengnam/libmnl-freebsd.git . Installation is done through standard automake tools.
As per common practice, I have seperated the userspace API from the kernel API (that has access to the userspace API). I kept it simple, and I kept the userspace api in linux/netlink.h and the kernel api in net/netlink.h
- m_buf handling: we currently assume the initial m_get to retreive a message of a sufficient size for a packet which allows us to write straight into the buffer instead of using m_append. The reason for this is because when "closing" a message, we call nlmsg_end or other functions to end the header, we use pointer artihmethic to determine the size of the message. Alternative is to call m_pullup before calling nlmsg_end on the message, or to continuously resize and transfer the message when more data is needed.
- module: currently installing netlink as a module rather than as part of the kernel tree
- genetlink: doit and dumpit functions need to be implemented