From: David Ahern <dsah...@kernel.org> Date: Thu, 11 Oct 2018 20:17:21 -0700
> From: David Ahern <dsah...@gmail.com> > > Another difference between IPv4 and IPv6 is the generation of RTM_DELROUTE > notifications when a device is taken down (admin down) or deleted. IPv4 > does not generate a message for routes evicted by the down or delete; > IPv6 does. A NOS at scale really needs to avoid these messages and have > IPv4 and IPv6 behave similarly, relying on userspace to handle link > notifications and evict the routes. > > At this point existing user behavior needs to be preserved. Since > notifications are a global action (not per app) the only way to preserve > existing behavior and allow the messages to be skipped is to add a new > sysctl (net/ipv6/route/skip_notify_on_dev_down) which can be set to > disable the notificatioons. > > IPv6 route code already supports the option to skip the message (it is > used for multipath routes for example). Besides the new sysctl we need > to pass the skip_notify setting through the generic fib6_clean and > fib6_walk functions to fib6_clean_node and to set skip_notify on calls > to __ip_del_rt for the addrconf_ifdown path. > > Signed-off-by: David Ahern <dsah...@gmail.com> > --- > v2 > - removed the changes to addrconf and anycast. addrconf_ifdown calls > rt6_disable_ip which calls rt6_sync_down_dev. The last one evicts all > routes for the device, so the delete route calls done later in addrconf > and anycast are superfluous Applied.
