Yes, this is what I liked about the 2 flag solution too compared to the original.
Dinesh On Thu, Jun 11, 2015 at 7:50 AM, Alexander Duyck <alexander.h.du...@redhat.com> wrote: > > > On 06/11/2015 04:23 AM, Andy Gospodarek wrote: >> >> On Wed, Jun 10, 2015 at 11:07:28PM -0700, Scott Feldman wrote: >>> >>> On Wed, Jun 10, 2015 at 7:37 PM, Andy Gospodarek >>> <go...@cumulusnetworks.com> wrote: >>>> >>>> Add a fib flag called RTNH_F_LINKDOWN to any ipv4 nexthops that are >>>> reachable via an interface where carrier is off. No action is taken, >>>> but additional flags are passed to userspace to indicate carrier status. >>> >>> Andy, it seems now RTNH_F_LINKDOWN and RTNH_F_DEAD are very similar >>> and I'm wondering if this could be done without introducing a new flag >>> and just use RTNH_F_DEAD. The link change event would set RTNH_F_DEAD >>> on nh on dev link down, and clear on link up. The sysctl knob would >>> be something like "nexthop_dead_on_linkdown", default off. So >>> basically expanding the ways RTNH_F_DEAD can be set. That would >>> simplify the patch set quite a bit and require no changes to iproute2. >>> >> You are absolutely correct that what you describe would be less churn to >> userspace. From a functionality standpoint that is close to what was >> originally proposed, but Alex specifically did not like the behavioral >> change to what having RTNH_F_DEAD set (at least that was what I >> understood). >> >> That was what made me make the move to add this additional flag that was >> exported to userspace, so it was possible to differentiate the old dead >> routes/nexthop functionality from those that were not going to be dead >> due to link being down. >> this point I think I prefer the additional data provided by the new >> flag exported to userspace. > > > I preferred the 2 flag solution as the original solution still required 2 > flags, it just only exposed 1 to user-space. As a result it was much more > error prone since it was fairly easy to get into a confused state about why > the link was dead. > > With the 2 flag solution it becomes much easier to sort out why the route is > not functional and it is much easier to isolate for things like the sysctl > which only disables the use of LINKDOWN and not DEAD. > > - Alex -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
