[PATCH net-next 0/3] SO_TXTIME improvements

[Willem de Bruijn <willemdebruijn.kernel@gmail.com>]

From: Willem de Bruijn <willemb@google.com>

FQ targets monotonic timestamps as generated by the TCP stack.

But SO_TXTIME was later added, which can send skbs with timestamps
against other clocks. It is now possible to detect these through skb
tstamp_type.

Make FQ robust by converting these timestamps for use in FQ (patch 2).

This also requires testing against out-of-bounds values. Prefer to do
this at the source, when parsing SCM_TXTIME (patch 1). But, tests in
the hot path are still needed, to handle BPF sources.

Extend the so_txtime selftest to handle this new case (patch 3).

The last patch would have a conflict in net. This is not stable
material, fine to go to net-next only.

Willem de Bruijn (3):
  net: ensure SCM_TXTIME delivery time is no older than system boot
  net_sched: sch_fq: convert skb->tstamp if not monotonic
  selftests: drv-net: extend so_txtime with FQ with other clocks

 net/core/sock.c                               | 32 +++++++++++++-
 net/sched/sch_fq.c                            | 43 ++++++++++++++++---
 .../selftests/drivers/net/so_txtime.py        | 18 ++++++--
 3 files changed, 83 insertions(+), 10 deletions(-)

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2.54.0.1032.g2f8565e1d1-goog