On 10/08/2021 13:38, Vladimir Oltean wrote: > On Tue, Aug 10, 2021 at 01:15:32PM +0300, Nikolay Aleksandrov wrote: >> On 10/08/2021 13:09, Vladimir Oltean wrote: >>> 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. >>> >> >> It's too late unfortunately, ignoring other flags in that case has been the standard >> behaviour for a long time (it has never made sense to specify flags for extern_learn >> entries). I'll send a separate patch that adds a comment to document it or if you have >> another thing in mind feel free to send a patch. > > No, I don't have anything else in mind, but since the topic is the same > as the "net: bridge: fix flags interpretation for extern learn fdb entries" > patch you already sent, you could as well just send a v2 for that and > add an extra phrase in a comment somewhere near a NTF_EXT_LEARNED uapi > definition, or perhaps extend this comment right here: > > /* NUD_NOARP & NUD_PERMANENT are pseudostates, they never change > and make no address resolution or NUD. > NUD_PERMANENT also cannot be deleted by garbage collectors. > */ > sure, I was going to send it for net-next, but I might as well do it in -net.
