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

Eric Dumazet
2026-04-01T09:14:59Z

On Wed, Apr 1, 2026 at 12:45 AM David Woodhouse <dwmw2@infradead.org> wrote:
>
> From: David Woodhouse <dwmw@amazon.co.uk>
>
> 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 ?