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

[Nicolai Buchwitz]

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.

> [...]

Thanks,
Nicolai