[PATCH net v2 0/3] vxlan: vnifilter: fix VNI add/update notifications

[Andy Roulin <aroulin@nvidia.com>]

When a vxlan device has vnifilter enabled, userspace observers
(e.g., bridge monitor vni) miss VNI add events and see spurious
notifications on no-op VNI re-adds.

Patch 1 fixes the missing notification on VNI add: vxlan_vni_add()
guarded the notification on a 'changed' flag that vxlan_vni_update_group()
only sets when a multicast group or remote is supplied, so VNIs added
without a group (e.g., L3 VXLAN) were silently created.

Patch 2 fixes the spurious notification on VNI update: vxlan_vni_update()
tested 'if (changed)' against a bool pointer instead of dereferencing it,
so every re-add produced a notification regardless of whether anything
actually changed.

Patch 3 adds a selftest covering both bugs along with a few related
cases (add with remote, remote update, delete-nonexistent).

Changes since v1:
- Retarget to net.
- Patch 3: improved vni_notify_check helper based on review by
  sashiko.dev:
  * Bump pre-cmd sleep 0.1s -> 0.5s.
  * Add /proc/$monitor_pid liveness check and ksft_skip if
    iproute2 doesn't support 'bridge monitor vni'.
  * Capture and propagate "$@"'s exit status so check_err $?
    actually validates the bridge command's return.

v1: https://lore.kernel.org/netdev/20260518165700.1975478-1-aroulin@nvidia.com/

Andy Roulin (3):
  vxlan: vnifilter: send notification on VNI add
  vxlan: vnifilter: fix spurious notification on VNI update
  selftests: net: add vxlan vnifilter notification test

 drivers/net/vxlan/vxlan_vnifilter.c           |   5 +-
 tools/testing/selftests/net/Makefile          |   1 +
 .../net/test_vxlan_vnifilter_notify.sh        | 184 ++++++++++++++++++
 3 files changed, 187 insertions(+), 3 deletions(-)
 create mode 100755 tools/testing/selftests/net/test_vxlan_vnifilter_notify.sh

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2.43.0