[PATCH 01/13 net-next] net: ipv4: introduce CONFIG_IPV4 to decouple the IPv4 stack

[Fernando Fernandez Mancera]

On 9/10/26 5:11 PM, Nicolai Buchwitz wrote:
> Hi Fernando,
> 
> Thanks for the patch - after nearly 30 years IPv6 should be mature 
> enough :)
> 
> On 10.9.2026 16:48, Fernando Fernandez Mancera wrote:
>> Historically, the IPv4 protocol has been linked to the core INET
>> subsystem. Because shared infrastructure like the TCP/UDP engine,
>> routing or INET hashtables live inside net/ipv4/, it has been impossible
>> to compile a kernel with only IPv6 support.
>>
>> This patch introduces the CONFIG_IPV4 Kconfig symbol, which is set to
>> 'def_bool y' for now. This does not allow to completely disable the
>> IPv4 stack yet but it lays the necessary build-system work for that
>> goal.
>>
>> In addition, multiple subsystems Kconfig symbols across networking
>> features like tunnels, drivers and filesystems have been adjusted to
>> depend on IPv4. Keep on mind that follow-up work is required to convert
>> the Kconfig symbol to bool and remove the dependency on IPv4 where it
>> makes sense.
>>
>> Signed-off-by: Fernando Fernandez Mancera <fmancera at suse.de>
>> ---
> 
>> [...]
> 
>> diff --git a/net/packet/Kconfig b/net/packet/Kconfig
>> index 2997382d597c..00fda9e08cb0 100644
>> --- a/net/packet/Kconfig
>> +++ b/net/packet/Kconfig
>> @@ -5,6 +5,7 @@
>>
>>  config PACKET
>>      tristate "Packet socket"
>> +    depends on IPV4
> 
>    depends on IPV4 || !INET
> 
> Otherwise this would break existing configs with INET=n. The same applies
> to other affected options that currently permit INET=n.

That is a good point. I will review the other configs too.

Thanks!
Fernando.

> 
>> [...]
> 
> Thanks,
> Nicolai
>