[PATCH pve-network 10/12] sdn: zones: offer dhcp on all zone types, keep dnsmasq simple-only

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

The dnsmasq backend is confined to simple zones because it is a
node-local process on the vnet bridge, on a zone spanning nodes
every node's instance would answer the shared broadcast domain. The
ebpf backend answers on the guest's own tap and has no such
restriction, so the dhcp property moves from a simple-zone option to
a common one, with dnsmasq rejected on other zone types.

The backends ask the zone for the guest-facing MTU to serve, so the
zone types gaining dhcp implement get_mtu, with vxlan derived zones
accounting for the encapsulation overhead.

Signed-off-by: Hannes Laimer <h.laimer@proxmox.com>
---
 src/PVE/API2/Network/SDN/Zones.pm         | 6 ++++++
 src/PVE/Network/SDN/Zones/EvpnPlugin.pm   | 1 +
 src/PVE/Network/SDN/Zones/FaucetPlugin.pm | 1 +
 src/PVE/Network/SDN/Zones/QinQPlugin.pm   | 7 +++++++
 src/PVE/Network/SDN/Zones/VlanPlugin.pm   | 7 +++++++
 src/PVE/Network/SDN/Zones/VxlanPlugin.pm  | 9 +++++++++
 6 files changed, 31 insertions(+)

diff --git a/src/PVE/API2/Network/SDN/Zones.pm b/src/PVE/API2/Network/SDN/Zones.pm
index ad16bef..b39c0c9 100644
--- a/src/PVE/API2/Network/SDN/Zones.pm
+++ b/src/PVE/API2/Network/SDN/Zones.pm
@@ -447,6 +447,9 @@ __PACKAGE__->register_method({
                 raise_param_exc({ ipam => "$ipam not existing" })
                     if $ipam && !$ipam_cfg->{ids}->{$ipam};
 
+                raise_param_exc({ dhcp => "the dnsmasq backend only supports simple zones" })
+                    if ($opts->{dhcp} // '') eq 'dnsmasq' && $plugin->type() ne 'simple';
+
                 $zone_cfg->{ids}->{$id} = $opts;
                 $plugin->on_update_hook($id, $zone_cfg, $controller_cfg);
 
@@ -543,6 +546,9 @@ __PACKAGE__->register_method({
                 raise_param_exc({ ipam => "$ipam not existing" })
                     if $ipam && !$ipam_cfg->{ids}->{$ipam};
 
+                raise_param_exc({ dhcp => "the dnsmasq backend only supports simple zones" })
+                    if ($opts->{dhcp} // '') eq 'dnsmasq' && $plugin->type() ne 'simple';
+
                 $plugin->on_update_hook($id, $zone_cfg, $controller_cfg);
 
                 PVE::Network::SDN::Zones::write_config($zone_cfg);
diff --git a/src/PVE/Network/SDN/Zones/EvpnPlugin.pm b/src/PVE/Network/SDN/Zones/EvpnPlugin.pm
index 0e79707..7f1fd90 100644
--- a/src/PVE/Network/SDN/Zones/EvpnPlugin.pm
+++ b/src/PVE/Network/SDN/Zones/EvpnPlugin.pm
@@ -125,6 +125,7 @@ sub options {
         reversedns => { optional => 1 },
         dnszone => { optional => 1 },
         ipam => { optional => 1 },
+        dhcp => { optional => 1 },
     };
 }
 
diff --git a/src/PVE/Network/SDN/Zones/FaucetPlugin.pm b/src/PVE/Network/SDN/Zones/FaucetPlugin.pm
index 5f069ae..4e3f5ef 100644
--- a/src/PVE/Network/SDN/Zones/FaucetPlugin.pm
+++ b/src/PVE/Network/SDN/Zones/FaucetPlugin.pm
@@ -30,6 +30,7 @@ sub options {
         reversedns => { optional => 1 },
         dnszone => { optional => 1 },
         ipam => { optional => 1 },
+        dhcp => { optional => 1 },
     };
 }
 
diff --git a/src/PVE/Network/SDN/Zones/QinQPlugin.pm b/src/PVE/Network/SDN/Zones/QinQPlugin.pm
index a75940c..e70912a 100644
--- a/src/PVE/Network/SDN/Zones/QinQPlugin.pm
+++ b/src/PVE/Network/SDN/Zones/QinQPlugin.pm
@@ -36,6 +36,12 @@ sub properties {
     };
 }
 
+sub get_mtu {
+    my ($class, $plugin_config) = @_;
+
+    return $plugin_config->{mtu};
+}
+
 sub options {
     return {
         nodes => { optional => 1 },
@@ -48,6 +54,7 @@ sub options {
         reversedns => { optional => 1 },
         dnszone => { optional => 1 },
         ipam => { optional => 1 },
+        dhcp => { optional => 1 },
     };
 }
 
diff --git a/src/PVE/Network/SDN/Zones/VlanPlugin.pm b/src/PVE/Network/SDN/Zones/VlanPlugin.pm
index 9102b34..4f24b2a 100644
--- a/src/PVE/Network/SDN/Zones/VlanPlugin.pm
+++ b/src/PVE/Network/SDN/Zones/VlanPlugin.pm
@@ -36,6 +36,12 @@ sub properties {
     };
 }
 
+sub get_mtu {
+    my ($class, $plugin_config) = @_;
+
+    return $plugin_config->{mtu};
+}
+
 sub options {
 
     return {
@@ -47,6 +53,7 @@ sub options {
         reversedns => { optional => 1 },
         dnszone => { optional => 1 },
         ipam => { optional => 1 },
+        dhcp => { optional => 1 },
     };
 }
 
diff --git a/src/PVE/Network/SDN/Zones/VxlanPlugin.pm b/src/PVE/Network/SDN/Zones/VxlanPlugin.pm
index a408261..6ae1998 100644
--- a/src/PVE/Network/SDN/Zones/VxlanPlugin.pm
+++ b/src/PVE/Network/SDN/Zones/VxlanPlugin.pm
@@ -47,6 +47,14 @@ sub properties {
     };
 }
 
+# without an explicit zone MTU the vnet bridges default to 1450,
+# leaving room for the vxlan encapsulation
+sub get_mtu {
+    my ($class, $plugin_config) = @_;
+
+    return $plugin_config->{mtu} // 1450;
+}
+
 sub options {
     return {
         nodes => { optional => 1 },
@@ -58,6 +66,7 @@ sub options {
         dnszone => { optional => 1 },
         ipam => { optional => 1 },
         fabric => { optional => 1 },
+        dhcp => { optional => 1 },
     };
 }
 
-- 
2.47.3