Re: [PATCH net-next v2 0/2] support SO_PRIORITY cmsg

[Ido Schimmel <idosch@idosch.org>]

On Sat, Nov 02, 2024 at 01:51:34PM +0100, Anna Emese Nyiri wrote:
> The changes introduce a new helper function,
> `sk_set_prio_allowed`, which centralizes the logic for validating
> priority settings. This series adds support for the `SO_PRIORITY`
> control message, allowing user-space applications to set socket
> priority via control messages (cmsg).
> 
> Patch Overview:
> Patch 1/2: Introduces `sk_set_prio_allowed` helper function.
> Patch 2/2: Implements support for setting `SO_PRIORITY` via control
> messages.
> 
> v2:
> - Suggested by Willem de Bruijn <willemdebruijn.kernel@gmail.com>
>   introduce "sk_set_prio_allowed" helper to check priority setting
>   capability
> - drop new fields and change sockcm_cookie::priority from "char" to
>   "u32" to match with sk_buff::priority
> - cork->tos value check before priority setting
>   moved from __ip_make_skb() to ip_setup_cork()
> - rebased on net-next
> 
> v1:
> https://lore.kernel.org/all/20241029144142.31382-1-annaemesenyiri@gmail.com/
> 
> Anna Emese Nyiri (2):
>   Introduce sk_set_prio_allowed helper function
>   support SO_PRIORITY cmsg
> 
>  include/net/inet_sock.h |  2 +-
>  include/net/ip.h        |  3 ++-
>  include/net/sock.h      |  4 +++-
>  net/can/raw.c           |  2 +-
>  net/core/sock.c         | 19 ++++++++++++++++---
>  net/ipv4/ip_output.c    |  7 +++++--
>  net/ipv4/raw.c          |  2 +-
>  net/ipv6/ip6_output.c   |  3 ++-
>  net/ipv6/raw.c          |  2 +-
>  net/packet/af_packet.c  |  2 +-
>  10 files changed, 33 insertions(+), 13 deletions(-)

Please consider adding a selftest for this feature. Willem already
extended tools/testing/selftests/net/cmsg_sender.c so that it could be
used to set SO_PRIORITY via setsockopt. You can extend it to set
SO_PRIORITY via cmsg and then use it in a test like
tools/testing/selftests/net/cmsg_so_mark.sh is doing for SO_MARK.