Side effect? - Re: Changing the content of tcp timeouts in ip_conntrack_proto_tcp.c

[Emmanuel Guiton <emmanuel@netlab.hut.fi>]

Hi!

I was a bit optimistic in my last e-mail. Compilation is totally ok, 
insertion of the modules in the kernel seems to go fine... until I want 
to use them. The nat table does not work anymore.
The ip_tables module seems to be there:
pc104:# iptables -L   
Chain INPUT (policy ACCEPT)
target     prot opt source               destination        

Chain FORWARD (policy ACCEPT)
target     prot opt source               destination        

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination  

But if I try the nat table:
pc104:# iptables -t nat -L
modprobe: Can't locate module ip_tables
iptables v1.2.9: can't initialize iptables table `nat': Table does not 
exist (do you need to insmod?)
Perhaps iptables or your kernel needs to be upgraded.

If I do not add my function in ip_conntrack_standalone.c, everything's 
ok (well except that I can't use my funciton of course).
To be very precise I just added the following:

In ip_conntrack_standalone.c:
EXPORT_SYMBOL(ip_ct_proto_tcp_set_timeouts);

In ip_conntrack.h:
extern void ip_ct_proto_tcp_set_timeous(/datatypes/);

In ip_conntrack_proto_tcp.c:
void ip_ct_proto_tcp_set_tcp_timeouts(unsigned long new_value, ...)
{
    ...
    ip_ct_tcp_timeout_established = new_value SECS;
    ...
}

And the calls to the function in ipt_MY_TARGET.c:
ip_ct_proto_tcp_set_timeouts(/values/);


What do I do wrong?

           Emmanuel



Emmanuel Guiton wrote:

> KOVACS Krisztian wrote:
>
>>  Hi,
>>
>> On Wed, 2004-01-14 at 13:39, Emmanuel Guiton wrote:
>>  
>>
>>>> Looks like you have not exported this function from ip_conntrack. 
>>>> To use a function from another module than it is defined in the 
>>>> function must first be exported from the module where it is defined.
>>>>     
>>>
>>> Well, I think I did. I defined my function in the 
>>> ip_conntrack_proto_tcp.c and I exported its prototype in 
>>> ip_conntrack.h.
>>> Then I call it in my target module which also uses ip_conntrack.h.
>>>   
>>
>>
>>  You have to explicitly export it using the EXPORT_SYMBOL() (or
>> EXPORT_SYMBOL_GPL) macro in ip_conntrack_standalone.c. It has a lot of
>> other exported symbols, just add another one.
>>
>>  
>>
> Right, it's working now.
> Thanks!
>
>           Emmanuel
>