Re: [PATCH 3/6] net: Guard Legacy IP entry points with CONFIG_LEGACY_IP

Eric Dumazet <[email protected]> Wed, 1 Apr 2026 02:14:45 -0700

Newsgroups	gmane.linux.network.bridge,gmane.linux.network,gmane.linux.drivers.rdma,gmane.linux.kernel,gmane.linux.kernel.bpf,gmane.linux.kernel.wireless.general,gmane.comp.security.firewalls.netfilter.devel
Message-ID	<CANn89i+iRUgqtd+eirfSUM3k+keNZKzLwsHxZtwE+vHdv7H5PQ@mail.gmail.com>

On Wed, Apr 1, 2026 at 12:45 AM David Woodhouse <[email protected]> wrote:
>
> From: David Woodhouse <[email protected]>
>
> Wrap the IPv4-specific registrations in inet_init() with
> CONFIG_LEGACY_IP guards. When LEGACY_IP is disabled, the kernel
> will not:
>  - Register the AF_INET socket family
>  - Register the ETH_P_IP packet handler (ip_rcv)
>  - Initialize ARP, ICMP, IGMP, or IPv4 routing
>  - Register IPv4 protocol handlers (TCP/UDP/ICMP over IPv4)
>  - Initialize IPv4 multicast routing, proc entries, or fragmentation
>
> The shared INET infrastructure (tcp_prot, udp_prot, tcp_init, etc.)
> remains initialized for use by IPv6.
>

...

>
>         /* Add UDP-Lite (RFC 3828) */
> -       udplite4_register();
> +       if (IS_ENABLED(CONFIG_LEGACY_IP))
> +               udplite4_register();

udplite has been removed in net-next.

I would think your patch series is net-next material ?