Re: [PATCH net-next 2/2] selftests: net: Add tests for ARP probe and DAD NS handling

On 29/04/2026 09:24, Danielle Ratson wrote:
> Add test cases to verify that ARP probes and DAD Neighbor Solicitations
> are handled correctly by the bridge neighbor suppression feature.
> 
> When neighbor suppression is enabled on a bridge VXLAN port, the bridge
> should reply to ARP/NS messages on behalf of remote hosts when both FDB
> and neighbor entries exist, and the answer is known. However, when
> either the FDB or the neighbor exists, ARP probes / DAD NS should be
> treated like regular ARP requests / NS and flood to VXLAN.
> 
> Add two new test functions:
> 
> neigh_suppress_arp_probe(): Tests ARP probe handling by triggering
> duplicate address detection using arping -D. Verifies that probes are
> flooded when the bridge doesn't know the answer, and suppressed when FDB
> and neighbor entries exist.
> 
> neigh_suppress_dad_ns(): Tests DAD NS handling by constructing DAD NS
> packets using mausezahn and verifies correct flooding/suppression
> behavior.
> 
> Before the previous patch:
> 
> $ ./test_bridge_neigh_suppress.sh -t "neigh_suppress_arp_probe neigh_suppress_dad_ns"
> 
> Per-port ARP probe suppression
> ------------------------------
> TEST: ARP probe suppression                                         [ OK ]
> TEST: "neigh_suppress" is on                                        [ OK ]
> TEST: ARP probe suppression                                         [FAIL]
> TEST: FDB and neighbor entry installation                           [ OK ]
> TEST: arping                                                        [FAIL]
> TEST: ARP probe suppression                                         [FAIL]
> TEST: neighbor removal                                              [ OK ]
> TEST: ARP probe suppression                                         [FAIL]
> TEST: "neigh_suppress" is off                                       [ OK ]
> TEST: ARP probe suppression                                         [FAIL]
> 
> Per-port DAD NS suppression
> ---------------------------
> TEST: DAD NS suppression                                            [ OK ]
> TEST: "neigh_suppress" is on                                        [ OK ]
> TEST: DAD NS suppression                                            [FAIL]
> TEST: FDB and neighbor entry installation                           [ OK ]
> TEST: DAD NS suppression                                            [FAIL]
> TEST: neighbor removal                                              [ OK ]
> TEST: DAD NS suppression                                            [FAIL]
> TEST: DAD NS proxy NA reply                                         [FAIL]
> TEST: "neigh_suppress" is off                                       [ OK ]
> TEST: DAD NS suppression                                            [FAIL]
> 
> Tests passed:   10
> Tests failed:   10
> 
> After the previous patch:
> 
> $ ./test_bridge_neigh_suppress.sh -t "neigh_suppress_arp_probe neigh_suppress_dad_ns"
> 
> Per-port ARP probe suppression
> ------------------------------
> TEST: ARP probe suppression                                         [ OK ]
> TEST: "neigh_suppress" is on                                        [ OK ]
> TEST: ARP probe suppression                                         [ OK ]
> TEST: FDB and neighbor entry installation                           [ OK ]
> TEST: arping                                                        [ OK ]
> TEST: ARP probe suppression                                         [ OK ]
> TEST: neighbor removal                                              [ OK ]
> TEST: ARP probe suppression                                         [ OK ]
> TEST: "neigh_suppress" is off                                       [ OK ]
> TEST: ARP probe suppression                                         [ OK ]
> 
> Per-port DAD NS suppression
> ---------------------------
> TEST: DAD NS suppression                                            [ OK ]
> TEST: "neigh_suppress" is on                                        [ OK ]
> TEST: DAD NS suppression                                            [ OK ]
> TEST: FDB and neighbor entry installation                           [ OK ]
> TEST: DAD NS suppression                                            [ OK ]
> TEST: neighbor removal                                              [ OK ]
> TEST: DAD NS suppression                                            [ OK ]
> TEST: DAD NS proxy NA reply                                         [ OK ]
> TEST: "neigh_suppress" is off                                       [ OK ]
> TEST: DAD NS suppression                                            [ OK ]
> 
> Tests passed:  20
> Tests failed:   0
> 
> Signed-off-by: Danielle Ratson <[email protected]>
> ---
>   .../net/test_bridge_neigh_suppress.sh         | 126 ++++++++++++++++++
>   1 file changed, 126 insertions(+)
> 

Acked-by: Nikolay Aleksandrov <[email protected]>