[PATCH net v4 0/2] vxlan: reset the remote's dst cache when snooping moves a MAC

[Zhefu Peng <ilskdw@gmail.com>]

When a learning VXLAN device snoops a known MAC from another VTEP, it
rewrites the remote's IP address in place but keeps the remote's
dst_cache and remote_ifindex. Traffic to the moved MAC can then use the
route cached for the previous remote and be blackholed. Patch 1 updates
the remote the way vxlan_fdb_replace() does. Patch 2 adds a selftest
for both cases.

The selftest fails both cases on net without patch 1 (8 of 8 runs with
1, 2 and 4 CPUs) and passes them with it (16 of 16 runs).

v4:
- add the selftest (Nicolas Dichtel)

v3: https://lore.kernel.org/netdev/20261111180001.2475-1-ilskdw@gmail.com/
- use my real name in From: and Signed-off-by:

v2: https://lore.kernel.org/netdev/20261110153020.9635-1-ilskdw@gmail.com/
- also update remote_ifindex and clear offloaded, as vxlan_fdb_replace() does
- add the IPv6 link-local case to the changelog and a second Fixes tag

v1: https://lore.kernel.org/netdev/20261106144406.66035-1-ilskdw@gmail.com/

Zhefu Peng (2):
  vxlan: reset the remote's dst cache when snooping moves a MAC
  selftests: net: add a test for vxlan snooping moving a MAC

 drivers/net/vxlan/vxlan_core.c                |   3 +
 tools/testing/selftests/net/Makefile          |   1 +
 .../selftests/net/test_vxlan_snoop_move.sh    | 161 ++++++++++++++++++
 3 files changed, 165 insertions(+)
 create mode 100755 tools/testing/selftests/net/test_vxlan_snoop_move.sh

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2.54.0