[pve-devel] [PATCH pve-network v2] sdn: evpn: fix IPv6 exitnode local routing

[Hannes Laimer]

On 1/19/26 12:08, Stefan Hanreich wrote:
> On 1/19/26 12:05 PM, Hannes Laimer wrote:
>> IPv6 subnets on exitnodes had no working local-routing path. Add a v6
>> address on the xvrf veth pair and install IPv6 routes via that next-hop.
>>
>> Signed-off-by: Hannes Laimer <h.laimer at proxmox.com>
>> ---
>> v2:
>>   - change `address6` to `address`, ifreload2 does not pick up address6.
>>     Probably had the address still attached from manualy testing so I
>>     didn't notice when I tested this for v1
>>
>>   src/PVE/Network/SDN/Controllers/EvpnPlugin.pm | 7 ++++++-
>>   src/PVE/Network/SDN/Zones/EvpnPlugin.pm       | 2 ++
>>   2 files changed, 8 insertions(+), 1 deletion(-)
>>
>> diff --git a/src/PVE/Network/SDN/Controllers/EvpnPlugin.pm b/src/PVE/Network/SDN/Controllers/EvpnPlugin.pm
>> index e53000a..74fc35d 100644
>> --- a/src/PVE/Network/SDN/Controllers/EvpnPlugin.pm
>> +++ b/src/PVE/Network/SDN/Controllers/EvpnPlugin.pm
>> @@ -462,7 +462,12 @@ sub generate_vnet_frr_config {
>>       foreach my $subnetid (sort keys %{$subnets}) {
>>           my $subnet = $subnets->{$subnetid};
>>           my $cidr = $subnet->{cidr};
>> -        push @controller_config, "ip route $cidr 10.255.255.2 xvrf_$zoneid";
>> +        my ($ip) = split(/\//, $cidr, 2);
>> +        if (Net::IP::ip_is_ipv6($ip)) {
>> +            push @controller_config, "ipv6 route $cidr fd00:ffff::2 xvrf_$zoneid";
> 
> Wouldn't it make sense to use the link-local address instead? For IPv4
> it would make sense as well imo to use an APIPA address instead, but
> technically that's a breaking change. I guess we could even route all
> IPv4 traffic via the IPv6 link-local address.
> 

I did try just
`ipv6 route $cidr xvrf_$zoneid`
since I assumed it would end up using the ll address, but it didn't. I
am not super sure why, maybe cause it would be cross-vrf(?).
Or did you mean just putting the ll address there explicitly?

>> +        } else {
>> +            push @controller_config, "ip route $cidr 10.255.255.2 xvrf_$zoneid";
>> +        }
>>       }
>>       push(@{ $config->{frr_ip_protocol} }, @controller_config);
>>   }
>> diff --git a/src/PVE/Network/SDN/Zones/EvpnPlugin.pm b/src/PVE/Network/SDN/Zones/EvpnPlugin.pm
>> index 6d89499..18aecb9 100644
>> --- a/src/PVE/Network/SDN/Zones/EvpnPlugin.pm
>> +++ b/src/PVE/Network/SDN/Zones/EvpnPlugin.pm
>> @@ -327,6 +327,7 @@ sub generate_sdn_config {
>>               @iface_config = ();
>>               push @iface_config, "link-type veth";
>>               push @iface_config, "address 10.255.255.1/30";
>> +            push @iface_config, "address fd00:ffff::1/126" if $ipv6;
>>               push @iface_config, "veth-peer-name $iface_xvrfp";
>>               push @iface_config, "mtu " . ($mtu + 50) if $mtu;
>>               push(@{ $config->{$iface_xvrf} }, @iface_config) if !$config->{$iface_xvrf};
>> @@ -334,6 +335,7 @@ sub generate_sdn_config {
>>               @iface_config = ();
>>               push @iface_config, "link-type veth";
>>               push @iface_config, "address 10.255.255.2/30";
>> +            push @iface_config, "address fd00:ffff::2/126" if $ipv6;
>>               push @iface_config, "veth-peer-name $iface_xvrf";
>>               push @iface_config, "vrf $vrf_iface";
>>               push @iface_config, "mtu " . ($mtu + 50) if $mtu;
> 
> 
> 
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