[NXOS] Add DHCPRelay provider implementation

Enable or disable the DHCP feature based on AdminState. When enabled,
configure DHCP relay on each referenced interface with the specified
server addresses.

The provider uses the VRF context from VrfRef (or the NXOS default
"!unspecified" if no VRF is specified) when configuring server
addresses.

The implementation uses the Update operation to ensure stale DHCP relay
entries are removed when the configuration changes. This also affects
entries referencing interfaces not managed by the operator.

The entire tree is removed on deletion, affecting non-managed interfaces.,
It leaves the DHCP feature in its current state.

GetDHCPRelayStatus queries the device for all interfaces with DHCP relay
configured and returns their names.

Author: nikatza

internal/controller/core/aaa_controller.go

@@ -26,10 +26,10 @@ import (
 	"sigs.k8s.io/controller-runtime/pkg/predicate"
 
 	"github.com/ironcore-dev/network-operator/api/core/v1alpha1"
-	"github.com/ironcore-dev/network-operator/internal/annotations"
 	"github.com/ironcore-dev/network-operator/internal/clientutil"
 	"github.com/ironcore-dev/network-operator/internal/conditions"
 	"github.com/ironcore-dev/network-operator/internal/deviceutil"
+	"github.com/ironcore-dev/network-operator/internal/paused"
 	"github.com/ironcore-dev/network-operator/internal/provider"
 	"github.com/ironcore-dev/network-operator/internal/resourcelock"
 )
@@ -102,9 +102,8 @@ func (r *AAAReconciler) Reconcile(ctx context.Context, req ctrl.Request) (_ ctrl
 		return ctrl.Result{}, err
 	}
 
-	if annotations.IsPaused(device, obj) {
-		log.Info("Reconciliation is paused for this object")
-		return ctrl.Result{}, nil
+	if isPaused, requeue, err := paused.EnsureCondition(ctx, r.Client, device, obj); isPaused || requeue || err != nil {
+		return ctrl.Result{}, err
 	}
 
 	if err := r.Locker.AcquireLock(ctx, device.Name, "aaa-controller"); err != nil {

internal/provider/cisco/nxos/provider.go

@@ -60,6 +60,7 @@ var (
 	_ provider.LLDPProvider             = (*Provider)(nil)
 	_ provider.DHCPRelayProvider        = (*Provider)(nil)
 	_ provider.AAAProvider              = (*Provider)(nil)
+	_ provider.DHCPRelayProvider        = (*Provider)(nil)
 )
 
 type Provider struct {
@@ -3119,6 +3120,65 @@ func (p *Provider) DeleteAAA(ctx context.Context, req *provider.DeleteAAARequest
 	return p.Update(ctx, conf...)
 }
 
+// EnsureDHCPRelay configures DHCP relay on the specified interfaces.
+// Replaces the entire DHCP relay configuration on the device with the provided configuration in the request.
+func (p *Provider) EnsureDHCPRelay(ctx context.Context, req *provider.DHCPRelayRequest) error {
+	f := new(Feature)
+	f.Name = "dhcp"
+	f.AdminSt = AdminStEnabled
+
+	// undocumented default value for the VRF property in DME (can be verified via NX-API)
+	vrfName := "!unspecified"
+	if req.VRF != nil {
+		vrfName = req.VRF.Spec.Name
+	}
+
+	conf := new(DHCPRelayConfig)
+	for _, intf := range req.Interfaces {
+		ifName, err := ShortName(intf.Spec.Name)
+		if err != nil {
+			return fmt.Errorf("dhcp relay: failed to get short name for interface %q: %w", intf.Spec.Name, err)
+		}
+
+		relay := &DHCPRelay{ID: ifName}
+		for _, addr := range req.DHCPRelay.Spec.Servers {
+			a, err := netip.ParseAddr(addr)
+			if err != nil {
+				return fmt.Errorf("dhcp relay: invalid server address %q: %w", addr, err)
+			}
+			relay.AddrItems.AddrList.Set(&DHCPRelayServer{Address: a, Vrf: vrfName})
+		}
+		conf.RelayIfList.Set(relay)
+	}
+
+	return p.Update(ctx, f, conf)
+}
+
+// DeleteDHCPRelay removes all DHCP relay configurations from the device.
+func (p *Provider) DeleteDHCPRelay(ctx context.Context, req *provider.DHCPRelayRequest) error {
+	config := new(DHCPRelayConfig)
+	return p.client.Delete(ctx, config)
+}
+
+// GetDHCPRelayStatus retrieves the current DHCP relay status.
+func (p *Provider) GetDHCPRelayStatus(ctx context.Context, req *provider.DHCPRelayRequest) (provider.DHCPRelayStatus, error) {
+	s := provider.DHCPRelayStatus{}
+	config := new(DHCPRelayConfig)
+	if err := p.client.GetConfig(ctx, config); err != nil {
+		if errors.Is(err, gnmiext.ErrNil) {
+			return s, nil
+		}
+		return s, fmt.Errorf("dhcp relay: failed to get status: %w", err)
+	}
+
+	s.ConfiguredInterfaces = make([]string, 0, config.RelayIfList.Len())
+	for _, relay := range config.RelayIfList {
+		s.ConfiguredInterfaces = append(s.ConfiguredInterfaces, relay.ID)
+	}
+
+	return s, nil
+}
+
 func init() {
 	provider.Register("cisco-nxos-gnmi", NewProvider)
 }