On Thu, Mar 10, 2016 at 03:03:11PM -0500, David Miller wrote:
> From: Cyrill Gorcunov <gorcunov@xxxxxxxxx>
> Date: Thu, 10 Mar 2016 23:01:34 +0300
>
> > On Thu, Mar 10, 2016 at 02:55:43PM -0500, David Miller wrote:
> >> >
> >> > Hmm, but inetdev_destroy() is only called when NETDEV_UNREGISTER
> >> > is happening and masq already registers a netdev notifier...
> >>
> >> Indeed, good catch. Therefore:
> >>
> >> 1) Keep the masq netdev notifier. That will flush the conntrack table
> >> for the inetdev_destroy event.
> >>
> >> 2) Make the inetdev notifier only do something if inetdev->dead is
> >> false. (ie. we are flushing an individual address)
> >>
> >> And then we don't need the NETDEV_UNREGISTER thing at all:
> >>
> >> diff --git a/net/ipv4/netfilter/nf_nat_masquerade_ipv4.c b/net/ipv4/netfilter/nf_nat_masquerade_ipv4.c
> >> index c6eb421..f71841a 100644
> >> --- a/net/ipv4/netfilter/nf_nat_masquerade_ipv4.c
> >> +++ b/net/ipv4/netfilter/nf_nat_masquerade_ipv4.c
> >> @@ -108,10 +108,20 @@ static int masq_inet_event(struct notifier_block *this,
> >> unsigned long event,
> >> void *ptr)
> >> {
> >> - struct net_device *dev = ((struct in_ifaddr *)ptr)->ifa_dev->dev;
> >> struct netdev_notifier_info info;
> >> + struct in_ifaddr *ifa = ptr;
> >> + struct in_device *idev;
> >>
> >> - netdev_notifier_info_init(&info, dev);
> >> + /* The masq_dev_notifier will catch the case of the device going
> >> + * down. So if the inetdev is dead and being destroyed we have
> >> + * no work to do. Otherwise this is an individual address removal
> >> + * and we have to perform the flush.
> >> + */
> >> + idev = ifa->ifa_dev;
> >> + if (idev->dead)
> >> + return NOTIFY_DONE;
> >> +
> >> + netdev_notifier_info_init(&info, idev->dev);
> >> return masq_device_event(this, event, &info);
> >> }
> >
> > Guys, I'm lost. Currently masq_device_event calls for conntrack
> > cleanup with device index, so that once device is going down, the
> > appropriate conntracks gonna be dropped off. Now if device is dead
> > nobody will cleanup the conntracks?
>
> Both notifiers are run in the inetdev_destroy() case.
>
> Maybe that's what you are missing.
No :) Look, here is what I mean. Previously with your two patches
we've been calling nf-cleanup for every address, so we had to make
code call for cleanup for one time only. Now with the patch above
the code flow is the following
inetdev_destroy
in_dev->dead = 1;
...
inet_del_ifa
...
blocking_notifier_call_chain(&inetaddr_chain, NETDEV_DOWN, ifa1);
...
masq_inet_event
...
masq_device_event
if (idev->dead)
return NOTIFY_DONE;
and nobody calls for nf_ct_iterate_cleanup, no?
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