[RFC PATCH 0/6] rust: net: introduce minimal rtnl/netdevice abstractions and nlmon reference driver

[Wenzhao Liao]

Hi,

This RFC proposes a minimal set of Rust networking abstractions for
link-type drivers, together with a Rust implementation of nlmon as a
reference driver.

The scope is intentionally narrow. The series only tries to cover the
pieces needed to model:

- rtnl link registration and validation
- net_device private state allocation
- sk_buff transmit ownership
- netlink tap lifetime management
- per-device stats updates

nlmon is a useful target for this because it is small, self-contained,
and exercises rtnl registration, netdevice setup, tap lifecycle, and
stats handling without introducing hardware-specific probe or teardown
paths.

The series is structured as follows:

- patches 1-2 expose the required bindings and helper glue
- patches 3-4 add the minimal Rust net abstractions
- patch 5 adds the Rust nlmon reference driver
- patch 6 adds scoped MAINTAINERS entries

The driver itself is built with #![forbid(unsafe_code)] and does not
call raw bindings directly. Unsafe is confined to small abstraction
implementations under rust/kernel/net/.

Validation so far:

- drivers/net/nlmon_rust.o builds successfully
- x86_64 bzImage builds successfully
- QEMU smoke passes:
  ip link add nlmon0 type nlmon
  ip link set nlmon0 up
  ip link show nlmon0
  ip link set nlmon0 down
  ip link del nlmon0

The Rust implementation is kept behind CONFIG_NLMON_RUST so the new
abstractions and the reference driver can be reviewed without displacing
the existing C implementation.

Feedback on the abstraction shape, the lifetime model, and whether
nlmon is a suitable reference driver would be especially appreciated.

I would also be grateful for guidance on any aspect of this series that
does not match Rust-for-Linux or netdev expectations. If the direction
is useful but the submission, factoring, or abstraction boundary needs
to change, I am happy to revise the series accordingly and resubmit.

Thanks,
Wenzhao Liao

Wenzhao Liao (6):
  rust: bindings: expose networking headers needed by nlmon
  rust: helpers: add net_device and sk_buff helper wrappers
  rust: net: add minimal skbuff, netdevice, and stats abstractions
  rust: net: add minimal rtnl registration and netlink tap support
  net: add Rust reference driver for nlmon
  MAINTAINERS: add Rust net and nlmon entries

 MAINTAINERS                     |  19 ++
 drivers/net/Kconfig             |   9 +
 drivers/net/Makefile            |   6 +-
 drivers/net/nlmon_rust.rs       |  93 ++++++++++
 rust/bindings/bindings_helper.h |   4 +
 rust/helpers/helpers.c          |   1 +
 rust/helpers/net.c              |  19 ++
 rust/kernel/net.rs              |   5 +
 rust/kernel/net/netdevice.rs    | 319 ++++++++++++++++++++++++++++++++
 rust/kernel/net/netlink_tap.rs  |  89 +++++++++
 rust/kernel/net/rtnl.rs         | 221 ++++++++++++++++++++++
 rust/kernel/net/skbuff.rs       |  67 +++++++
 rust/kernel/net/stats.rs        |  17 ++
 13 files changed, 868 insertions(+), 1 deletion(-)
 create mode 100644 drivers/net/nlmon_rust.rs
 create mode 100644 rust/helpers/net.c
 create mode 100644 rust/kernel/net/netdevice.rs
 create mode 100644 rust/kernel/net/netlink_tap.rs
 create mode 100644 rust/kernel/net/rtnl.rs
 create mode 100644 rust/kernel/net/skbuff.rs
 create mode 100644 rust/kernel/net/stats.rs

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2.34.1