[PATCH perl-rs v5 07/10] fabrics: openfabric: enable force_forwarding for ipv6 transit traffic

[Lukas Sichert <l.sichert@proxmox.com>]

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 interfaces. With the addition of
'force_forwarding' to the Linux kernel, this can be done without
enabling 'all.forwarding', which disables Router Advertisements for the
whole host.

Configure fabric interfaces with the ifupdown2 ip6-force-forward flag.

Signed-off-by: Lukas Sichert <l.sichert@proxmox.com>
---

Notes:
    In [1] I said that I would prevent setting the flag on dummy interfaces.
    As the ip-forward flag is set on dummy interfaces as well I think it
    would be more confusing to not also set ip6-forward and
    ip6-force-forward. The flags will therefore also be set on dummy
    interfaces.
    
    [1] https://lore.proxmox.com/all/DM6DIG3FPYS6.I5M2777SP04X@proxmox.com/

 pve-rs/src/bindings/sdn/fabrics.rs | 1 +
 1 file changed, 1 insertion(+)

diff --git a/pve-rs/src/bindings/sdn/fabrics.rs b/pve-rs/src/bindings/sdn/fabrics.rs
index 74e1140..8413168 100644
--- a/pve-rs/src/bindings/sdn/fabrics.rs
+++ b/pve-rs/src/bindings/sdn/fabrics.rs
@@ -601,6 +601,7 @@ pub mod pve_rs_sdn_fabrics {
         writeln!(interface, "\tip-forward 1")?;
         if cidr.is_ipv6() {
             writeln!(interface, "\tip6-forward 1")?;
+            writeln!(interface, "\tip6-force-forward 1")?;
         }
 
         Ok(interface)
-- 
2.47.3