On Tue, Aug 10, 2021 at 09:46:34AM +0300, Ido Schimmel wrote: > On Mon, Aug 09, 2021 at 04:05:22PM +0000, Vladimir Oltean wrote: > > On Mon, Aug 09, 2021 at 03:16:40PM +0300, Ido Schimmel wrote: > > > I have at least once selftest where I forgot the 'static' keyword: > > > > > > bridge fdb add de:ad:be:ef:13:37 dev $swp1 master extern_learn vlan 1 > > > > > > This patch breaks the test when run against both the kernel and hardware > > > data paths. I don't mind patching these tests, but we might get more > > > reports in the future. > > > > Is it the 'static' keyword that you forgot, or 'dynamic'? The > > tools/testing/selftests/net/forwarding/bridge_vlan_aware.sh selftest > > looks to me like it's testing the behavior of an FDB entry which should > > roam, and which without the extern_learn flag would be ageable. > > static - no aging, no roaming > dynamic - aging, roaming > extern_learn - no aging, roaming > > So these combinations do not make any sense and the kernel will ignore > static/dynamic when extern_learn is specified. It's needed to work > around iproute2 behavior of "assume permanent" Since NTF_EXT_LEARNED is part of ndm->ndm_flags and NUD_REACHABLE/NUD_NOARP are part of ndm->ndm_state, it is not at all clear to me that 'extern_learn' belongs to the same class of bridge neighbor attributes as 'static'/'dynamic', and that it is invalid to have the full degree of freedom. If it isn't, shouldn't the kernel validate that, instead of just ignoring the ndm->ndm_state? If it's too late to validate, shouldn't we at least document somewhere that the ndm_state is ignored in the presence of ndm_flags & NTF_EXT_LEARNED? It is user API after all, easter eggs like this aren't very enjoyable.
