From: Cyrill Gorcunov <gorcunov@xxxxxxxxx>
Date: Thu, 10 Mar 2016 23:13:51 +0300
> 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?
Oh yes they do, from masq's non-inet notifier. masq registers two
notifiers, one for generic netdev and one for inetdev.
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