Anna Nyiri wrote:

Ido Schimmel [off-list ref] ezt írta (időpont: 2024. nov. 3., V, 17:25):

quoted

On Sat, Nov 02, 2024 at 01:51:34PM +0100, Anna Emese Nyiri wrote:

quoted

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 [off-list ref]
  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/ (local)

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.

Of course, I will send the test. However, I would first like to
clarify which option I should assign in cmsg_sender for setting
priority via cmsg. The -P option is already used for setting priority
with setsockopt(), and -p is used to specify the protocol.

Thanks for adding test coverage.

If all the Ps are taken, use Q. It's a rare letter, and happens to be
the next. In the end, whatever is available.