Merge branch 'tcp-exclude-old-acks-from-fast-path'

Inbal Schussheim says:

====================
tcp: exclude old ACKs from fast path

Exclude ACKs outside [SND.UNA, SND.NXT] from TCP header prediction so
that they fall through to the slow path, where ACK
validation is applied.

Add a packetdrill test for a data segment carrying an
excessively old ACK. The test fails on the unpatched kernel and passes
with the fix.

v2: https://lore.kernel.org/netdev/20260909075644.1408171-1-inbal.lipshtat@mail.huji.ac.il/
v1: https://lore.kernel.org/netdev/20260906123151.1391349-1-inbal.lipshtat@mail.huji.ac.il/T/#u
====================

Link: https://patch.msgid.link/20260914090408.1435080-1-inbal.lipshtat@mail.huji.ac.il
Signed-off-by: Paolo Abeni <pabeni@redhat.com>