[SRU][N][PATCH 0/4] re-enable Ubuntu FAN in the Noble kernel

[Andrea Righi]

BugLink: https://bugs.launchpad.net/bugs/2064508

[Impact]

In LP: #2063298, we have opted to deprecate Ubuntu FAN support because
of the maintenance overhead and the possibility of regressions /
conflicts with the new networking eBPF APIs in kernels >= 6.8.

However, we cannot disable this feature in HWE/backport kernels, so it
seems safer to adjust the Ubuntu FAN kernel patch set to ensure proper
co-existence with the updated vxlan policy requirements in newer 6.8
kernels.

The re-introduction of Ubuntu FAN should be considered as a temporary
measure, aimed at facilitating a smooth transition during its
deprecation without disrupting existing users (specifically Juju), and
enabling the backporting of 6.8 kernels to older releases.

The main plan is still to deprecate Ubuntu FAN in newer releases.

[Test case]

Rely on the specific Ubuntu FAN regression test to validate the proper
kernel support of this feature:

https://git.launchpad.net/~canonical-kernel-team/+git/autotest-client-tests/tree/ubuntu_fan_smoke_test?h=autotest3

[Fix]

Re-apply the Ubuntu FAN patch set to the latest Noble kernel 6.8 and
integrate the IFLA_VXLAN_FAN_MAP attribute type in vxlan_policy to
satisfy the strict length validation check.

Test result (ubuntu_fan_smoke_test) with this patch set applied to the
latest Noble kernel:

 11:48:05 INFO | Writing results to /home/ubuntu/autotest/client/results/default
 11:48:05 INFO | START	----	----	timestamp=1714564085	localtime=May 01 11:48:05
 11:48:05 INFO | 	START	ubuntu_fan_smoke_test.setup	ubuntu_fan_smoke_test.setup	timeout=1200	timestamp=1714564085	localtime=May 01 11:48:05
 11:48:07 INFO | 		GOOD	ubuntu_fan_smoke_test.setup	ubuntu_fan_smoke_test.setup	timestamp=1714564087	localtime=May 01 11:48:07	completed successfully
 11:48:07 INFO | 	END GOOD	ubuntu_fan_smoke_test.setup	ubuntu_fan_smoke_test.setup	timestamp=1714564087	localtime=May 01 11:48:07
 11:48:07 INFO | 	START	ubuntu_fan_smoke_test.fan-smoke-test	ubuntu_fan_smoke_test.fan-smoke-test	timeout=1800	timestamp=1714564087	localtime=May 01 11:48:07
 11:51:46 INFO | Testing Fan Networking (pre-0.13.0 API)
 11:51:46 INFO | docker pull --platform linux/amd64 ubuntu: PASSED
 11:51:46 INFO | enable disable fan test: PASSED
 11:51:46 INFO | fanctl show test: PASSED
 11:51:46 INFO | fanctl check bridge config test: PASSED
 11:51:46 INFO | fanatic docker test(--dns=192.168.122.1): PASSED
 11:51:47 INFO | 		GOOD	ubuntu_fan_smoke_test.fan-smoke-test	ubuntu_fan_smoke_test.fan-smoke-test	timestamp=1714564307	localtime=May 01 11:51:47	completed successfully
 11:51:47 INFO | 	END GOOD	ubuntu_fan_smoke_test.fan-smoke-test	ubuntu_fan_smoke_test.fan-smoke-test	timestamp=1714564307	localtime=May 01 11:51:47
 11:51:47 INFO | END GOOD	----	----	timestamp=1714564307	localtime=May 01 11:51:47
 11:51:47 INFO | Report successfully generated at /home/ubuntu/autotest/client/results/default/job_report.html

[Regression potential]

We may experience regressions with eBPF vxlan capabilities and
potentially specific use cases of the Ubuntu FAN technology (Juju
installations).

----------------------------------------------------------------
Andrea Righi (1):
      UBUNTU: SAUCE: fan: support vxlan strict length validation

Jay Vosburgh (2):
      UBUNTU: SAUCE: fan: tunnel multiple mapping mode (v3)
      UBUNTU: SAUCE: fan: add VXLAN implementation

Juerg Haefliger (1):
      UBUNTU: SAUCE: fan: Fix NULL pointer dereference

 drivers/net/vxlan/vxlan_core.c | 264 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 include/net/ip_tunnels.h       |  28 +++++++++++
 include/net/vxlan.h            |   2 +
 include/uapi/linux/if_link.h   |   1 +
 include/uapi/linux/if_tunnel.h |  19 ++++++++
 net/ipv4/ip_tunnel.c           |   2 +-
 net/ipv4/ipip.c                | 311 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 7 files changed, 624 insertions(+), 3 deletions(-)