searching tuples in conntrack

searching tuples in conntrack

[Miguel Alejandro González]

Hello,

I have been reading some kernel code trying to find a function that
searches the conntrack hash table for a transport address and returns
the given tuple. Is there any way to do this? I found a function in
the nat code called find_appropriate_src but i think it only works for
the nat table...

Regards

Re: searching tuples in conntrack

[Jan Engelhardt]

On Wednesday 2012-09-26 19:29, Miguel Alejandro González wrote:

>Hello,
>
>I have been reading some kernel code trying to find a function that
>searches the conntrack hash table for a transport address and returns
>the given tuple. Is there any way to do this? I found a function in
>the nat code called find_appropriate_src but i think it only works for
>the nat table...

nf_conntrack_find_get(...) is the one to use for CT lookup.
(Cf. xt_connlimit.c)

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Re: searching tuples in conntrack

[Miguel Alejandro González]

Hello

I'm having some problems creating a function like count_them and the
hash table it uses. My module is a target extension and connlimit is a
match extension.

So correct me if I'm wrong... basically connlimit creates an extra
hash table with struct xt_connlimit_info *info = par->matchinfo as a
parameter to save conntracks and tuples, but I don't have such info
because i'm making a target extension... Can't I do a lookup directly
to the NFCT list?

How can I initialize the hash table like in connlimit_mt_check() if I
don't work with const struct xt_mtchk_param *par?

Can you point in the right direction? I'm really new to kernel dev.. I
hope I'm not asking too much of you

Regards


On Wed, Sep 26, 2012 at 3:32 PM, Jan Engelhardt <jengelh@inai.de> wrote:
> On Wednesday 2012-09-26 19:29, Miguel Alejandro González wrote:
>
>>Hello,
>>
>>I have been reading some kernel code trying to find a function that
>>searches the conntrack hash table for a transport address and returns
>>the given tuple. Is there any way to do this? I found a function in
>>the nat code called find_appropriate_src but i think it only works for
>>the nat table...
>
> nf_conntrack_find_get(...) is the one to use for CT lookup.
> (Cf. xt_connlimit.c)
>
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> To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in
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Re: searching tuples in conntrack

[Jan Engelhardt]

On Sunday 2012-10-07 07:51, Miguel Alejandro González wrote:
>
>I'm having some problems creating a function like count_them and the hash
>table it uses. My module is a target extension and connlimit is a match
>extension.

And why would that be a problem?

>So correct me if I'm wrong... basically connlimit creates the hash table
>with struct xt_connlimit_info *info = par->matchinfo as a parameter, but I
>don't have such info because i'm making a target extension...

par->targinfo is the block of parameters received from userspace
for targets.

>How can I initialize the hash table like in connlimit_mt_check() if I don't
>work with const struct xt_mtchk_param *par?

    →   info->data = kmalloc(sizeof(myprivatestuff), GFP_KERNEL);     

Note how this does not have much to do with matchinfo.
It's simply an assignment.
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