Re: [PATCH pve-container v3 14/17] net: report NIC plugs and removals to the SDN DHCP backends

[Stefan Hanreich <s.hanreich@proxmox.com>]

Tested-by: Stefan Hanreich <s.hanreich@proxmox.com>

On 10/20/26 10:02 AM, Hannes Laimer wrote:
> An SDN DHCP backend answers a guest NIC with the address IPAM holds
> for its MAC. A NIC joining its bridge now hands its MAC to the SDN
> plug, so the backend of its vnet can answer its first request.
> Deleting a veth also reports it as gone to the backends, since their
> state for an interface can outlive it.
> 
> On a running container, a bridge change now pushes the DHCP mapping
> for the new vnet, as adding a NIC or changing its MAC already does.
> 
> Signed-off-by: Hannes Laimer <h.laimer@proxmox.com>
> ---
>  src/PVE/LXC.pm            | 13 +++++++++++--
>  src/PVE/LXC/Config.pm     |  3 ++-
>  src/lxc-pve-poststop-hook |  6 +++---
>  3 files changed, 16 insertions(+), 6 deletions(-)
> 
> diff --git a/src/PVE/LXC.pm b/src/PVE/LXC.pm
> index 1f11490..c3cf9e7 100644
> --- a/src/PVE/LXC.pm
> +++ b/src/PVE/LXC.pm
> @@ -1111,7 +1111,13 @@ sub net_tap_plug : prototype($$) {
>      my $create_firewall_bridges = $net->{firewall} && PVE::Firewall::Helpers::needs_fwbr($bridge);
>  
>      PVE::Network::SDN::Zones::tap_plug(
> -        $iface, $bridge, $tag, $create_firewall_bridges, $trunks, $rate,
> +        $iface,
> +        $bridge,
> +        $tag,
> +        $create_firewall_bridges,
> +        $trunks,
> +        $rate,
> +        { mac => $hwaddr },

nit: I understand that this function already has quite a few arguments, but introducing a new
$opts and then setting the MAC there seems somewhat awkward as well? A matter of taste though, I
suppose..

>      );
>      PVE::Network::SDN::Zones::add_bridge_fdb($iface, $hwaddr, $bridge);
>  
> @@ -1137,7 +1143,7 @@ sub update_net {
>              || safe_string_ne($oldnet->{name}, $newnet->{name})
>          ) {
>  
> -            PVE::Network::veth_delete($veth);
> +            PVE::Network::SDN::Zones::veth_delete($veth);
>  
>              if (safe_string_ne($oldnet->{hwaddr}, $newnet->{hwaddr})) {
>                  eval {
> @@ -1192,6 +1198,9 @@ sub update_net {
>                      PVE::Network::SDN::Vnets::add_next_free_cidr(
>                          $newnet->{bridge}, $conf->{hostname}, $newnet->{hwaddr}, $vmid, undef, 1,
>                      );
> +                    PVE::Network::SDN::Vnets::add_dhcp_mapping(
> +                        $newnet->{bridge}, $newnet->{hwaddr}, $vmid, $conf->{hostname},
> +                    );
>                  }
>                  eval { PVE::LXC::net_tap_plug($veth, $newnet) };
>                  if (my $err = $@) {
> diff --git a/src/PVE/LXC/Config.pm b/src/PVE/LXC/Config.pm
> index 9823d00..b522413 100644
> --- a/src/PVE/LXC/Config.pm
> +++ b/src/PVE/LXC/Config.pm
> @@ -12,6 +12,7 @@ use PVE::GuestHelpers;
>  use PVE::INotify;
>  use PVE::JSONSchema qw(get_standard_option);
>  use PVE::Network::SDN::Vnets;
> +use PVE::Network::SDN::Zones;
>  use PVE::RESTEnvironment;
>  use PVE::Tools;
>  
> @@ -1696,7 +1697,7 @@ sub vmconfig_hotplug_pending {
>                  my $net = parse_lxc_network($conf->{$opt});
>                  PVE::LXC::kill_dhclients($vmid, $net->{name}) if $net->{'host-managed'};
>  
> -                PVE::Network::veth_delete("veth${vmid}i$netid");
> +                PVE::Network::SDN::Zones::veth_delete("veth${vmid}i$netid");
>                  print "delete ips from $opt\n";
>                  eval {
>                      PVE::Network::SDN::Vnets::del_ips_from_mac(
> diff --git a/src/lxc-pve-poststop-hook b/src/lxc-pve-poststop-hook
> index c8bbb79..c5d1059 100755
> --- a/src/lxc-pve-poststop-hook
> +++ b/src/lxc-pve-poststop-hook
> @@ -11,7 +11,7 @@ use PVE::GuestHelpers;
>  use PVE::LXC::Config;
>  use PVE::LXC::Tools;
>  use PVE::LXC;
> -use PVE::Network;
> +use PVE::Network::SDN::Zones;
>  use PVE::RESTEnvironment;
>  use PVE::Storage;
>  use PVE::Tools;
> @@ -49,8 +49,8 @@ PVE::LXC::Tools::lxc_hook(
>              my $ind = $1;
>              my $net = PVE::LXC::Config->parse_lxc_network($conf->{$k});
>              next if $net->{type} ne 'veth';
> -            # veth_delete tests with '-d /sys/class/net/$name' before running the command
> -            PVE::Network::veth_delete("veth${vmid}i$ind");
> +            # reports the unplug and deletes the veth only where it still exists
> +            PVE::Network::SDN::Zones::veth_delete("veth${vmid}i$ind");
>          }
>  
>          my $config_updated = 0;