Merge branch 'selftests-net-ioam-add-tunsrc-support'

Merge branch 'selftests-net-ioam-add-tunsrc-support'

Justin Iurman says:

====================
selftests: net: ioam: add tunsrc support

TL;DR This patch comes from a discussion we had with Jakub and Paolo on
aligning the ioam selftests with its new "tunsrc" feature.

This patch updates the IOAM selftests to support the new "tunsrc"
feature of IOAM. As a consequence, some changes were required. For
example, the IPv6 header must be accessed to check some fields (i.e.,
the source address for the "tunsrc" feature), which is not possible
AFAIK with IPv6 raw sockets. The latter is currently used with
IPV6_RECVHOPOPTS and was introduced by commit 187bbb6968af ("selftests:
ioam: refactoring to align with the fix") to fix an issue. But, we
really need packet sockets actually... which is one of the changes in
this patch (see the description of the topology at the top of ioam6.sh
for explanations). Another change is that all IPv6 addresses used in the
topology are now based on the documentation prefix (2001:db8::/32).
Also, the tests have been improved and there are now many more of them.
Overall, the script is more robust.
====================

Link: https://patch.msgid.link/20241002162731.19847-1-justin.iurman@uliege.be
Signed-off-by: Jakub Kicinski <kuba@kernel.org>