Re: Disable IPv6 at startup?

[Grant Edwards <grant.b.edwards@xxxxxxxxx>]

On 2012-03-01, Sergei Gavrikov <sergei.gavrikov@xxxxxxxxx> wrote:
> On Wed, 29 Feb 2012, Grant Edwards wrote:
>
> [snip]
>
>> OK, I've come up with something I like a little better.  The only
>> change it requires to the network stack is that ip6_init2() needs to
>> be globally visible (ip6_init already is, so I don't see the harm in
>> making ip6_init2 visible).  If ip6_init2 is visible, then you can
>> disable ipv6 support with this code:
>> 
>> static void init_noop(void* dummy)
>> {
>> }
>> 
>> static void disable_ipv6(void)
>> {
>>   extern void cyg_net_add_domain(void *);
>>   extern void ip6_init2(void *);
>>   extern char inet6domain[];
>>   extern struct init_tab_entry __NET_INIT_TAB__[], __NET_INIT_TAB_END__;
>>   struct init_tab_entry *init_entry;
>> 
>>   for (init_entry = __NET_INIT_TAB__; init_entry != &__NET_INIT_TAB_END__;  init_entry++) 
>>       if ((init_entry->fun == cyg_net_add_domain && init_entry->data == (void*)inet6domain) ||
>>           (init_entry->fun == ip6_init2))
>>           init_entry->fun = init_noop;
>> }

In case anybody is wondering, ip6_init() is called via the domain
startup code via a pointer that's present in the "struct domain"
initializer for inet6domain. Disabling the call to
cyg_net_add_domain(&inet6domain) as shown above is what prevents
ip6_init() from being called.

> IMHO, it is neat solution. Thanks for usage example. BTW, the KAME's
> successors had declared ip6_init2() as you suggest:
>
>   http://ftp.fr.openbsd.org/pub/OpenBSD/src/sys/netinet6/ip6_input.c
>
> Please, submit the patch.

OK, will do.  I noticed after that last post that ip6_init is renamed
to cyg_ip6_init by one of the include files.  I assume I should do the
same thing for ip6_init2 if it's going to be global?

-- 
Grant Edwards               grant.b.edwards        Yow! But was he mature
                                  at               enough last night at the
                              gmail.com            lesbian masquerade?


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