On Mon, Jul 22, 2019 at 03:06:24PM +0200, Florian Westphal wrote: > Phil Sutter <phil@xxxxxx> wrote: > > On Mon, Jul 22, 2019 at 02:56:33PM +0200, Florian Westphal wrote: > > > Phil Sutter <phil@xxxxxx> wrote: > > > > On Mon, Jul 22, 2019 at 02:17:47PM +0200, Florian Westphal wrote: > > > > > Phil Sutter <phil@xxxxxx> wrote: > > > > > > use for "no data available" situations. This whole attempt feels a bit > > > > > > futile. Maybe we should introduce something to signal "no value" so that > > > > > > cmp expression will never match for '==' and always for '!='? Not sure > > > > > > how to realize this via registers. Also undecided about '<' and '>' ops. > > > > > > > > > > Whats the point? > > > > > > > > IIRC, Pablo's demand for not aborting in nft_meta in case of > > > > insufficient data was to insert a value into dreg which will never > > > > match. I think the idea was to avoid accidental matching in situations > > > > where a match doesn't make sense. > > > > > > I think the only contraint is that it must not overlap with a > > > legitimate ifindex. > > > > > > But 0 cannot occur, so 'meta iif 0' will only match in case no input > > > interface existed -- I think thats fine and might even be desired. > > > > OK, so we just drop my patch to reject ifindex 0 from userspace to keep > > fib working? > > > > [...] > > > I would propose to go with '0' dreg for ifindex, "" for name and leave > > > rest as-is. > > > > My kernel patch also changes iftype to set ARPHRD_VOID and ifkind to set > > an empty string as well. > > I would keep both with current semantics, i.e. 'break'/no match until we > get more evidence that we need this ARPHDR_VOID store. > > For iifkind, I am not sure. Perhaps leave it as-is? > > Kernel doesn't allow "" iifname (so we can reuse it for 'no interface'), > but what about ifkind? Well, at least every implementation of rtnl_link_ops I found in current kernel sources initializes 'kind' field but there's indeed no guarantee. > > For iftype, I also sent a userspace patch to disallow ARPHRD_VOID. Do > > you think it should be dropped as well? > > I think we should leave userspace alone. OK. Thanks, Phil
