Re: [PATCH 1/4] rust: netlink: add raw netlink abstraction

[Alice Ryhl <aliceryhl@google.com>]

On Sat, Mar 07, 2026 at 04:43:02PM +0100, Andrew Lunn wrote:
> > diff --git a/rust/kernel/netlink.rs b/rust/kernel/netlink.rs
> 
> ...
> 
> > +/// The default netlink message size.
> > +pub const GENLMSG_DEFAULT_SIZE: usize = bindings::GENLMSG_DEFAULT_SIZE;
> > +
> > +/// A wrapper around `struct sk_buff` for generic netlink messages.
> > +///
> > +/// # Invariants
> > +///
> > +/// The pointer has ownership over a valid `sk_buff`.
> > +pub struct SkBuff {
> > +    skb: NonNull<kernel::bindings::sk_buff>,
> > +}
> 
> struct sk_buff is a core data structure which appears all over the
> networking stack, but also other places like crypto, scsi, tty, file
> systems, etc. Since it is a top level data structure, it seems odd
> Rust puts it into netlink.rs.
> 
> How do you see the Rust SkBuff evolving to a general purpose data
> structure which can be used everywhere?

We can make a kernel::net module (rust/kernel/net/) and put it there
instead? I guess netlink.rs can also be a submodule of that.

Hmm ... but I'm currently using genlmsg_new() / nlmsg_free(), and I
assume the other use-cases do not go through those methods, since they
sound netlink specific.

To be honest, I'm new to the kernel's networking stack, so I probably
can't design Rust wrapper for sk_buff that supports all those different
usecases without someone walking me through how it works. It may or may
not be best to write a netlink-specific struct now and expand it later.

Alice