linux-kernel - Re: [PATCH net-next v6] ipv6: add `force_forwarding` sysctl to enable per-interface forwarding

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Message-ID: <cb12d567-6654-48b0-8443-522aaddcc406@redhat.com>
Date: Tue, 15 Jul 2025 15:34:56 +0200
From: Paolo Abeni <pabeni@...hat.com>
To: Gabriel Goller <g.goller@...xmox.com>,
 Nicolas Dichtel <nicolas.dichtel@...nd.com>,
 "David S. Miller" <davem@...emloft.net>, Eric Dumazet <edumazet@...gle.com>,
 Jakub Kicinski <kuba@...nel.org>, Simon Horman <horms@...nel.org>,
 Jonathan Corbet <corbet@....net>, David Ahern <dsahern@...nel.org>,
 Shuah Khan <shuah@...nel.org>
Cc: netdev@...r.kernel.org, linux-doc@...r.kernel.org,
 linux-kernel@...r.kernel.org, linux-kselftest@...r.kernel.org
Subject: Re: [PATCH net-next v6] ipv6: add `force_forwarding` sysctl to enable
 per-interface forwarding

On 7/11/25 2:42 PM, Gabriel Goller wrote:
> It is currently impossible to enable ipv6 forwarding on a per-interface
> basis like in ipv4. To enable forwarding on an ipv6 interface we need to
> enable it on all interfaces and disable it on the other interfaces using
> a netfilter rule. This is especially cumbersome if you have lots of
> interface and only want to enable forwarding on a few. According to the
> sysctl docs [0] the `net.ipv6.conf.all.forwarding` enables forwarding
> for all interfaces, while the interface-specific
> `net.ipv6.conf.<interface>.forwarding` configures the interface
> Host/Router configuration.
> 
> Introduce a new sysctl flag `force_forwarding`, which can be set on every
> interface. The ip6_forwarding function will then check if the global
> forwarding flag OR the force_forwarding flag is active and forward the
> packet.
> 
> To preserver backwards-compatibility reset the flag (on all interfaces)
> to 0 if the net.ipv6.conf.all.forwarding flag is set to 0.
> 
> Add a short selftest that checks if a packet gets forwarded with and
> without `force_forwarding`.
> 
> [0]: https://www.kernel.org/doc/Documentation/networking/ip-sysctl.txt
> 
> Signed-off-by: Gabriel Goller <g.goller@...xmox.com>
> Acked-by: Nicolas Dichtel <nicolas.dichtel@...nd.com>
> ---
> v6: 
>     * rebase
>     * remove brackts around single line
>     * add 'nodad' to addresses in selftest to avoid sporadic failures

I'm sorry, but it still does not apply. Please rebase again and re-submit.

Thanks,

Paolo