Re: [PATCH perl-rs 3/4] fabrics: openfabric: enable force_forwarding for ipv6 transit traffic

[Hannes Laimer <h.laimer@proxmox.com>]

On 2026-06-02 11:02, Gabriel Goller wrote:
> On 01.06.2026 17:15, Lukas Sichert wrote:
>> In a non-full-mesh OpenFabric setup, nodes may need to relay traffic
>> between peers that are not directly connected. This requires forwarding
>> ipv6 packets between fabric bridges. With the addition of
>> 'force_forwarding' to the Linux kernel, this can be done without
>> enabling 'all.forwarding', which disables Router Advertisements.
>>
>> Configure fabric bridges with the required 'post-up'/'post-down'
>> commands to enable 'force_forwarding'.
>>
>> Signed-off-by: Lukas Sichert <l.sichert@proxmox.com>
>> ---
>>  pve-rs/src/bindings/sdn/fabrics.rs | 10 ++++++++++
>>  1 file changed, 10 insertions(+)
>>
>> diff --git a/pve-rs/src/bindings/sdn/fabrics.rs b/pve-rs/src/bindings/sdn/fabrics.rs
>> index f96b6b1..785b537 100644
>> --- a/pve-rs/src/bindings/sdn/fabrics.rs
>> +++ b/pve-rs/src/bindings/sdn/fabrics.rs
>> @@ -596,6 +596,16 @@ pub mod pve_rs_sdn_fabrics {
>>              writeln!(interface, "\tlink-type {link_type}")?;
>>          }
>>          writeln!(interface, "\tip-forward 1")?;
>> +        if cidr.is_ipv6() {
>> +            writeln!(
>> +                interface,
>> +                "\tpost-up echo 1 > /proc/sys/net/ipv6/conf/{name}/force_forwarding"
>> +            )?;
>> +            writeln!(
>> +                interface,
>> +                "\tpost-down echo 0 > /proc/sys/net/ipv6/conf/{name}/force_forwarding"
>> +            )?;
>> +        }
>>  
>>          Ok(interface)
>>      }
> 
> The bgp fabric also needs force_forwarding AFAIK. @Hannes?

yes, we also need it there, same thing

> 
> Also I just noticed on the bgp fabric we put ipv6 addresses in ifupdown2 inet
> blocks (instead of inet6) -- shouldn't cause any problems though.