Add OpenConfig DNS provider implementation

internal/provider/openconfig/dns.go

@@ -0,0 +1,107 @@
+// SPDX-FileCopyrightText: 2026 SAP SE or an SAP affiliate company and IronCore contributors
+// SPDX-License-Identifier: Apache-2.0
+
+package openconfig
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/ironcore-dev/network-operator/api/core/v1alpha1"
+	"github.com/ironcore-dev/network-operator/internal/apistatus"
+	"github.com/ironcore-dev/network-operator/internal/provider"
+	"github.com/ironcore-dev/network-operator/internal/transport/gnmiext"
+)
+
+var _ provider.DNSProvider = (*Provider)(nil)
+
+func (p *Provider) EnsureDNS(ctx context.Context, req *provider.EnsureDNSRequest) error {
+	spec := req.DNS.Spec
+	if err := validateDNSSpec(spec); err != nil {
+		return err
+	}
+
+	d := &DNS{
+		Config: &DNSConfig{
+			Search: []string{spec.Domain},
+		},
+	}
+
+	if len(spec.Servers) > 0 {
+		d.Servers = &DNSServers{}
+		for _, s := range spec.Servers {
+			d.Servers.Server.Set(&DNSServer{
+				Address: s.Address,
+				Config:  &DNSServerConfig{Address: s.Address},
+			})
+		}
+	}
+
+	return p.client.Update(ctx, d)
+}
+
+func (p *Provider) DeleteDNS(ctx context.Context) error {
+	return p.client.Delete(ctx, &DNS{})
+}
+
+func validateDNSSpec(spec v1alpha1.DNSSpec) error {
+	var violations []apistatus.FieldViolation
+	if spec.AdminState == v1alpha1.AdminStateDown {
+		violations = append(violations, apistatus.FieldViolation{
+			Field:       "spec.adminState",
+			Description: "adminState Down is not supported by the OpenConfig DNS model",
+		})
+	}
+	if spec.SourceInterfaceName != "" {
+		violations = append(violations, apistatus.FieldViolation{
+			Field:       "spec.sourceInterfaceName",
+			Description: "sourceInterfaceName is not supported by the OpenConfig DNS model",
+		})
+	}
+	for _, s := range spec.Servers {
+		if s.VrfName != "" {
+			violations = append(violations, apistatus.FieldViolation{
+				Field:       fmt.Sprintf("spec.servers[%s].vrfName", s.Address),
+				Description: "vrfName is not supported by the OpenConfig DNS model",
+			})
+		}
+	}
+	if len(violations) > 0 {
+		return apistatus.NewUnsupportedFieldError(violations...)
+	}
+	return nil
+}
+
+// Compile-time assertions.
+var _ gnmiext.DataElement = (*DNS)(nil)
+
+// DNS represents the OpenConfig /system/dns container.
+type DNS struct {
+	Config  *DNSConfig  `json:"config,omitempty"`
+	Servers *DNSServers `json:"servers,omitempty"`
+}
+
+func (*DNS) XPath() string { return "openconfig-system:system/dns" }
+
+// DNSConfig holds the config container for DNS.
+type DNSConfig struct {
+	Search []string `json:"search,omitempty"`
+}
+
+// DNSServers holds the servers container for DNS.
+type DNSServers struct {
+	Server gnmiext.List[string, *DNSServer] `json:"server,omitempty"`
+}
+
+// DNSServer represents a single DNS server entry.
+type DNSServer struct {
+	Address string           `json:"address"`
+	Config  *DNSServerConfig `json:"config,omitempty"`
+}
+
+func (s *DNSServer) Key() string { return s.Address }
+
+// DNSServerConfig holds the config container for a DNS server.
+type DNSServerConfig struct {
+	Address string `json:"address"`
+}

internal/provider/openconfig/dns_test.go

@@ -0,0 +1,41 @@
+// SPDX-FileCopyrightText: 2026 SAP SE or an SAP affiliate company and IronCore contributors
+// SPDX-License-Identifier: Apache-2.0
+
+package openconfig
+
+import (
+	"bytes"
+	"encoding/json"
+	"os"
+	"testing"
+)
+
+func Test_DNS_Payload(t *testing.T) {
+	servers := &DNSServers{}
+	address := "1.1.1.1"
+	servers.Server.Set(&DNSServer{Address: address, Config: &DNSServerConfig{Address: address}})
+
+	d := &DNS{
+		Config:  &DNSConfig{Search: []string{"example.com"}},
+		Servers: servers,
+	}
+
+	got, err := json.Marshal(d)
+	if err != nil {
+		t.Fatalf("json.Marshal() error = %v", err)
+	}
+
+	data, err := os.ReadFile("testdata/dns.json")
+	if err != nil {
+		t.Fatalf("os.ReadFile() error = %v", err)
+	}
+
+	var want bytes.Buffer
+	if err := json.Compact(&want, data); err != nil {
+		t.Fatalf("json.Compact() error = %v", err)
+	}
+
+	if !bytes.Equal(want.Bytes(), got) {
+		t.Errorf("payload mismatch:\nwant: %s\n got: %s", want.Bytes(), got)
+	}
+}

internal/provider/openconfig/testdata/dns.json

@@ -0,0 +1,17 @@
+{
+  "config": {
+    "search": [
+      "example.com"
+    ]
+  },
+  "servers": {
+    "server": [
+      {
+        "address": "1.1.1.1",
+        "config": {
+          "address": "1.1.1.1"
+        }
+      }
+    ]
+  }
+}

test/gnmi/testdata/openconfig/dns.txt

@@ -0,0 +1,42 @@
+# DNS Configuration
+-- dns/dns --
+apiVersion: networking.metal.ironcore.dev/v1alpha1
+kind: DNS
+metadata:
+  name: dns
+  namespace: default
+spec:
+  deviceRef:
+    name: device
+  domain: example.com
+  servers:
+    - address: 8.8.8.8
+    - address: 1.1.1.1
+-- state --
+{
+  "openconfig-system:system": {
+    "dns": {
+      "config": {
+        "search": [
+          "example.com"
+        ]
+      },
+      "servers": {
+        "server": [
+          {
+            "address": "8.8.8.8",
+            "config": {
+              "address": "8.8.8.8"
+            }
+          },
+          {
+            "address": "1.1.1.1",
+            "config": {
+              "address": "1.1.1.1"
+            }
+          }
+        ]
+      }
+    }
+  }
+}