feat(dhcp): DHCPv4-Server via Kea (kea-dhcp4-server) — v1.2.92

Verwalteter DHCPv4-Server analog Unbound/Squid/Chrony.
- Migration 0041: dhcp_settings (singleton, node-lokal), dhcp_subnets, dhcp_reservations.
- internal/kea: Renderer baut Kea-JSON via Go-Struct→Marshal (garantiert valide), managed /etc/edgeguard/kea/kea-dhcp4.conf (Symlink von /etc/kea), Service-Lifecycle an enabled gekoppelt (default AUS, kein rogue DHCP). Interface per NAME (cluster-sicher, kein node-lokaler FK).
- internal/services/dhcp + internal/handlers/dhcp.go: Settings + Subnet/Reservation-CRUD, Validierung (CIDR/IP/MAC/interface exists).
- configgen: Stop/Enable/DisableService. Firewall: AutoFWRule.Iface → udp/67 pro LAN-Interface gescopt (kein WAN). Cluster: subnets/reservations repliziert (hashSpec), dhcp_settings node-lokal (localOnlyTables).
- main.go + render.go + WithAllReloaders Wiring. Packaging: kea-dhcp4-server Dependency, /etc/edgeguard/kea Dir, Symlink, disable-on-install, sudoers (restart/stop/enable/disable).
- UI: DHCP-Seite (Settings + Subnets + Reservierungen pro Subnet), Route/Nav/i18n de/en, HA-Warnung 'nur auf einer Node aktivieren'.
- Tests (guarded EG_FWTEST_DSN): Kea-Renderer gegen DB (valides JSON + Felder), FW-Auto-Rule-Iface inkl. nft -c. Scope v1: DHCPv4.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

internal/kea/kea_test.go

@@ -0,0 +1,89 @@
+package kea
+
+import (
+	"context"
+	"encoding/json"
+	"os"
+	"os/exec"
+	"strings"
+	"testing"
+	"time"
+
+	"git.netcell-it.de/projekte/edgeguard-native/internal/database"
+)
+
+// Guarded integration test: set EG_FWTEST_DSN (sonst skip).
+func TestRender_DHCPConfig(t *testing.T) {
+	dsn := os.Getenv("EG_FWTEST_DSN")
+	if dsn == "" {
+		t.Skip("set EG_FWTEST_DSN to run the kea renderer test")
+	}
+	ctx := context.Background()
+	var mErr error
+	for i := 0; i < 3; i++ {
+		if mErr = database.Migrate(ctx, dsn); mErr == nil {
+			break
+		}
+		time.Sleep(700 * time.Millisecond)
+	}
+	if mErr != nil {
+		t.Fatalf("migrate: %v", mErr)
+	}
+	pool, err := database.Open(ctx, dsn)
+	if err != nil {
+		t.Fatalf("open: %v", err)
+	}
+	defer pool.Close()
+
+	for _, q := range []string{
+		`DELETE FROM dhcp_reservations`,
+		`DELETE FROM dhcp_subnets`,
+		`UPDATE dhcp_settings SET enabled=true, default_lease=3600, max_lease=7200, domain_name='lan', dns_servers='1.1.1.1, 8.8.8.8' WHERE id=1`,
+	} {
+		if _, err := pool.Exec(ctx, q); err != nil {
+			t.Fatalf("seed (%s): %v", q, err)
+		}
+	}
+	var subID int64
+	if err := pool.QueryRow(ctx, `
+INSERT INTO dhcp_subnets (name, interface_name, subnet_cidr, pool_start, pool_end, gateway, dns_servers, active)
+VALUES ('lan','eth1','10.0.0.0/24','10.0.0.100','10.0.0.200','10.0.0.1','',true) RETURNING id`).Scan(&subID); err != nil {
+		t.Fatalf("seed subnet: %v", err)
+	}
+	if _, err := pool.Exec(ctx, `
+INSERT INTO dhcp_reservations (subnet_id, mac_address, ip_address, hostname, active)
+VALUES ($1,'aa:bb:cc:dd:ee:ff','10.0.0.50','printer',true)`, subID); err != nil {
+		t.Fatalf("seed reservation: %v", err)
+	}
+
+	out, err := New(pool).RenderToString(ctx)
+	if err != nil {
+		t.Fatalf("render: %v", err)
+	}
+	if !json.Valid([]byte(out)) {
+		t.Fatalf("rendered config is not valid JSON:\n%s", out)
+	}
+	for _, want := range []string{
+		`"10.0.0.0/24"`,
+		`"10.0.0.100 - 10.0.0.200"`,
+		`"aa:bb:cc:dd:ee:ff"`,
+		`"routers"`,
+		`"eth1"`,
+		`"hw-address"`,
+		`"valid-lifetime": 3600`,
+	} {
+		if !strings.Contains(out, want) {
+			t.Errorf("rendered config missing %q\n----\n%s", want, out)
+		}
+	}
+
+	// Best-effort: echte Kea-Validierung, falls die Binary da ist.
+	if _, statErr := os.Stat(keaBinary); statErr == nil {
+		f, _ := os.CreateTemp(t.TempDir(), "kea-*.conf")
+		_, _ = f.WriteString(out)
+		f.Close()
+		if combined, err := exec.Command(keaBinary, "-t", f.Name()).CombinedOutput(); err != nil {
+			t.Fatalf("kea-dhcp4 -t rejected rendered config: %v\n%s", err, combined)
+		}
+	}
+}