conntrack-utils needs to autoload netlink

conntrack-utils needs to autoload netlink

[Jan Engelhardt]

Hi,


I observed that running `conntrack -E` does not autoload 
nf_conntrack_netlink.ko, and as such, does not receive any events. 
`conntrack -L` on the other hand does autoload it, and subsequent -E 
works.


Jan

Re: conntrack-utils needs to autoload netlink

[Pablo Neira Ayuso]

Jan Engelhardt wrote:
> Hi,
> 
> I observed that running `conntrack -E` does not autoload 
> nf_conntrack_netlink.ko, and as such, does not receive any events. 
> `conntrack -L` on the other hand does autoload it, and subsequent -E 
> works.

Yes, that's a known issue. The problem is the following: with `conntrack
-L', netlink loads nfnetlink when the socket is created, then nfnetlink
receives a message requesting a dump, thus, nfnetlink loads
nf_conntrack_netlink. However, with `conntrack -E', netlink loads
nfnetlink, but nfnetlink does not receive any message from conntrack
since listening to events doesn't require such operation. thus,
nf_conntrack_netlink is not loaded.

I wrote a patch time ago to load nf_conntrack_netlink from user-space
when `conntrack -E' is invoked. I don't see a way to fix this in the
kernel code, so that's the only idea that I can find to fix this
problem. Still, I don't like too much the idea of doing the autoload
from user-space.

-- 
"Los honestos son inadaptados sociales" -- Les Luthiers

Re: conntrack-utils needs to autoload netlink

[Patrick McHardy]

Pablo Neira Ayuso wrote:
> I wrote a patch time ago to load nf_conntrack_netlink from user-space
> when `conntrack -E' is invoked. I don't see a way to fix this in the
> kernel code, so that's the only idea that I can find to fix this
> problem. Still, I don't like too much the idea of doing the autoload
> from user-space.

You could add a callback for multicast-binds and have that callback
load the nfnetlink-specific module.