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

[Fernando Fernandez Mancera]

On 9/10/26 6:22 PM, Fernando Fernandez Mancera wrote:
> On 9/10/26 4:48 PM, 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>
> FWIW, I just checked and the following symbols that are currently marked 
> as "depends on IPV4" can already be compiled without IPV4:
> 
> IPV6_MIP6, IPV6_ILA and IPV6_MROUTE
> 

MIP6 depends on XFRM so it actually depends on IPV4 for now.

> They will be adjusted on the next revision of the series. A re-check for 
> all the symbols will be performed.
> 
> Thanks,
> Fernando.