netlink-rs

This project aims at providing building blocks for the netlink protocol (see man 7 netlink).

The netlink protocol is huge but the two most widely used subprotocols are the generic netlink protocol and the route netlink protocol (see man 7 rtnetlink).

The project is in its early stages, and I'm currently focusing on the route netlink protocol.

Organization

• the netlink-sys crate provides low level building blocks: constants, socket, and packet parsing
• the netlink-ip crate provides higher level abstractions for the route netlink protocol. It is fully asynchronous and built on top of tokio.

Other netlink projects in rust

Before starting working on this library, I've checked a bunch of other projects but none seems to be really complete.

• https://github.com/achanda/netlink: rust bindings for netlink. Does not seem very usable as is, and does not seem to be developped anymore.
• https://github.com/polachok/pnetlink: very similar to this project, but built on to of libpnet. The author seems to be more knowledgeable about netlink than I am. It also has broader coverage of the route netlink protocol (support for the RTM_{NEW,DEL,GET}ROUTE and RTM_{NEW,DEL,GET}ADDRESS messages). However, many attributes supported by netlink-sys are not covered.
• https://github.com/crhino/netlink-rs: rust bindings for libnl. Very incomplete and not developed.
• https://github.com/jbaublitz/neli: generic netlink protocol. Pretty recent project, actively developed.
• https://github.com/carrotsrc/rsnl: bindings for libnl. Maintained but not actively developed.
• https://github.com/TaborKelly/nl-utils: a netlink packet parser. The goal is not that same than this project.

Other non-rust netlink projects

• libnl: netlink implementation in C. Very complete with awesome documentation.
• pyroute2: a very complete and readable implementation in pure python.
• netlink: a very complete and very actively maintained go project, seems to be widely used.

Credits

My main resource so far have been the source code of pyroute2 and netlink a lot. These two projects are great, and very nicely written. As someone who does not read C fluently, and that does not know much about netlink, they have been invaluable.

I'd also like to praise libnl for its documentation. It helped me a lot in understanding the protocol basics.

The whole packet parsing logic is inspired by @whitequark excellent blog posts (part 1, part 2 and part 3, although I've only really used the concepts described in the first blog post). These ideas are also being used in @m-labs's smoltcp project.

Thanks also to the people behing tokio, especially @carllerche, for the amazing tool they are building, and the support they provide. The project structure and code quality are mind blowing, and some parts of this projects are basically rip-offs from tokio's source code.

Finally, thanks to the Rust community, which helped me in multiple occations.

Other resources I particularly appreciated:

• https://www.linuxjournal.com/article/7356
• https://medium.com/@mdlayher/linux-netlink-and-go-part-1-netlink-4781aaeeaca8