netlink.md

Netlink

The Netlink socket family is a Linux kernel interface used for inter-process communication (IPC) between both the kernel and userspace processes, and between different userspace processes, in a way similar to the Unix domain sockets. ^{wikipedia.org}

It was introduced to primarily replace ioctl.

It's used e.g. by the iproute2 utilities which "are often recommended over now-obsolete net-tools utilities" ^{wikipedia.org}.

To create a socket of AF_NETLINK type one should call socket in the following way:

netlink_socket = socket(AF_NETLINK, socket_type, netlink_family);

where:

• socket is either SOCK_RAW or SOCK_DGRAM as both values are allowed
• netlink_family is one of may allowed values like e.g. NETLINK_ROUTE or NETLINK_GENERIC

More extensive documentation on the how to use netlink sockets in C code can be found at https://linux.die.net/man/7/netlink.

There also exist implementations in many different languages including https://github.com/vishvananda/netlink written in Go.

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There's a great lightning talk by Matt Layher from GopherCon 2018 where he describes netlink and its families.