Re: [PATCH docs/manager/network/perl-rs v4 0/6] sdn: enable force_forwarding for ipv6 forwarding

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

Generally this works well, and is a very solid improvment over what we
currently have. Aside from the comments on the patches, it looks like
some tests need updating :P

```
	modified:   src/test/zones/evpn/bgp_fabric/expected_sdn_interfaces
	modified:   src/test/zones/evpn/openfabric_fabric_ipv6/expected_sdn_interfaces
	modified:   src/test/zones/evpn/openfabric_fabric_ipv6_only/expected_sdn_interfaces
```

On 2026-07-27 15:55, Lukas Sichert wrote:
> Gabriel's upstream kernel patch [1] added
> net.ipv6.conf.<iface>.force_forwarding. This allows enabling IPv6
> forwarding on selected interfaces without requiring
> net.ipv6.conf.all.forwarding.
> 
> This is useful for SDN setups because all.forwarding has host-wide side
> effects. In particular, it disables Router Advertisement processing by
> default, which can break SLAAC on unrelated interfaces. SDN only needs
> forwarding on the VNet, exit-node, or fabric interfaces that participate
> in routed IPv6 traffic.
> 
> This series generates ifupdown post-up/post-down commands for those
> interfaces so force_forwarding is enabled when the interface is brought
> up and reset when it is brought down. /network/interfaces.d/sdn gets
> regenerated on SDN Apply. This means that removing a VNet also removes
> the corresponding 'post-down' commands configured to the interface of
> the VNet. Therefore it cannot happen, that deleting one VNet in the GUI
> removes force_forwarding on the outgoing interfaces, which might be used
> by other VNets as well. The tests are adjusted for the generated
> /etc/network/interfaces.d/sdn output. Also the series rewrites the
> documentation to reflect the updated behaviour and removes the UI warning
> to enable 'all.forwarding'.
> 
> 
> [1] lkml.org/lkml/2025/7/7/577
> 
> changes from v3 to v4 (thanks @Stefan):
> -wrap resolving outgoing interface in eval block
> -remove unnecessary 'ip6-forward' for vrfbr interface
> -Drop the fabric edit GUI hint that told users to enable
> net.ipv6.conf.all.forwarding
> -remove whitespace formatting changes
> 
> changes from v2 to v3 (thanks @Gabriel):
> -Move the IPv6 force_forwarding post-up/post-down commands out of the
> subnet loop, so they are generated only once for the VNet instead of
> once per subnet.
> -Enable ip6-forward and force_forwarding on EVPN L3VNI VRF bridge
> interfaces, fixing IPv6 forwarding when traffic exits through another
> node.
> 
> changes from v1 to v2 (thanks @Gabriel, @Hannes):
> -add force_forwarding also to bgp fabrics
> -explicitly mention the force_forwarding flag in the documentation
> -add a reference link to the sysctl documentation
> -mention bgp as a fabric with ipv6 support
> 
> 
> network:
> 
> Lukas Sichert (2):
>   sdn: evpn: enable force_forwarding for ipv6 forwarding to subnets
>   sdn: simple: enable force_forwarding for ipv6 forwarding to subnets
> 
>  src/PVE/Network/SDN/Zones/EvpnPlugin.pm       | 34 ++++++++++++++++++-
>  src/PVE/Network/SDN/Zones/SimplePlugin.pm     | 25 +++++++++++++-
>  .../expected_sdn_interfaces                   |  6 ++++
>  .../exitnode_snat/expected_sdn_interfaces     |  4 +++
>  .../exitnodenullroute/expected_sdn_interfaces |  6 ++++
>  .../evpn/ipv4ipv6/expected_sdn_interfaces     |  4 +++
>  .../zones/evpn/ipv6/expected_sdn_interfaces   |  4 +++
>  .../evpn/ipv6underlay/expected_sdn_interfaces |  4 +++
>  .../simple/ipv4v6/expected_sdn_interfaces     |  4 +++
>  .../simple/ipv6snat/expected_sdn_interfaces   |  4 +++
>  10 files changed, 93 insertions(+), 2 deletions(-)
> 
> 
> perl-rs:
> 
> Lukas Sichert (2):
>   fabrics: openfabric: enable force_forwarding for ipv6 transit traffic
>   fabrics: bgp: enable force_forwarding for ipv6 transit traffic
> 
>  pve-rs/src/bindings/sdn/fabrics.rs | 18 ++++++++++++++++++
>  1 file changed, 18 insertions(+)
> 
> 
> manager:
> 
> Lukas Sichert (1):
>   ui: sdn: remove IPv6 forwarding hint from fabric edit window
> 
>  www/manager6/sdn/fabrics/FabricEdit.js | 59 +++++++++-----------------
>  1 file changed, 20 insertions(+), 39 deletions(-)
> 
> 
> docs:
> 
> Lukas Sichert (1):
>   sdn: drop global ipv6 forwarding workaround from OpenFabric docs
> 
>  pvesdn.adoc | 21 +++++----------------
>  1 file changed, 5 insertions(+), 16 deletions(-)
> 
> 
> Summary over all repositories:
>   13 files changed, 136 insertions(+), 57 deletions(-)
> 
> -- 
> Generated by murpp 0.12.0
> 
> 
> 
>