kea

modules/kea/migrations/002_1.1.0_groups.php

@@ -0,0 +1,26 @@
+<?php
+declare(strict_types=1);
+
+use App\Database;
+use App\ModuleMigrationContext;
+use App\Repository\KeaHostMetadataRepository;
+
+return new class {
+    public function up(ModuleMigrationContext $context): void
+    {
+        $settings = $context->settings();
+        $fallback = is_array($context->module['metadata_db_defaults'] ?? null)
+            ? $context->module['metadata_db_defaults']
+            : [];
+        $config = is_array($settings['metadata_db'] ?? null)
+            ? array_replace($fallback, $settings['metadata_db'])
+            : $fallback;
+
+        if (empty($config['driver']) || empty($config['dbname'])) {
+            return;
+        }
+
+        $repo = new KeaHostMetadataRepository(Database::createFromArray($config));
+        $repo->ensureSchema();
+    }
+};

modules/kea/module.json

@@ -1,10 +1,11 @@
 {
   "title": "KEA DHCP",
-  "version": "1.0.0",
+  "version": "1.1.0",
-  "schema_version": 1,
+  "schema_version": 2,
   "description": "Verwaltung von KEA DHCP Hosts und Reservierungen.",
   "menu": [
     { "label": "Hosts", "href": "/module/kea" },
+    { "label": "Gruppen", "href": "/module/kea/groups" },
     { "label": "Setup", "href": "/modules/setup/kea" }
   ],
   "sidebar": {
@@ -13,6 +14,7 @@
     "default": "collapsed",
     "items": [
       { "label": "Hosts", "href": "/module/kea" },
+      { "label": "Gruppen", "href": "/module/kea/groups" },
       { "label": "Setup", "href": "/modules/setup/kea" }
     ]
   },

modules/kea/pages/edit.php

@@ -19,6 +19,7 @@ $notice = null;
 $host = null;
 $metadataRepo = null;
 $groups = [];
+$availableIpsByGroup = [];
 
 try {
     $pdo = modules()->modulePdo('kea', $fallback);
@@ -64,11 +65,19 @@ try {
         }
         $host = $repo->findDisplayByKey($source, $id) ?: $host;
     }
+
+    $usedIps = array_diff(
+        array_merge($repo->usedIpAddresses(), $metadataRepo->desiredIps()),
+        [(string)($host['ipv4_address'] ?? ''), (string)($host['metadata']['desired_ip'] ?? '')]
+    );
+    $availableIpsByGroup = $metadataRepo->availableIpsByGroup($usedIps);
 } catch (Throwable $e) {
     $error = $e->getMessage();
 }
 
 $metadata = is_array($host['metadata'] ?? null) ? $host['metadata'] : [];
+$selectedGroup = (string)($metadata['group_name'] ?? '');
+$selectedIp = (string)($metadata['desired_ip'] ?? '');
 ?>
 <section class="kea-page">
   <div class="section-head">
@@ -128,17 +137,19 @@ $metadata = is_array($host['metadata'] ?? null) ? $host['metadata'] : [];
         </label>
         <label class="setup-field">
           <span>Gruppe</span>
-          <input type="text" name="group_name" list="kea-groups" value="<?= e((string)($metadata['group_name'] ?? '')) ?>">
+          <select name="group_name" data-kea-group-select>
-          <datalist id="kea-groups">
+            <option value="">Bitte waehlen</option>
             <?php foreach ($groups as $group): ?>
-              <option value="<?= e($group) ?>"></option>
+              <option value="<?= e($group) ?>" <?= $selectedGroup === $group ? 'selected' : '' ?>><?= e($group) ?></option>
             <?php endforeach; ?>
-          </datalist>
+          </select>
         </label>
         <label class="setup-field">
           <span>Feste IP</span>
-          <input type="text" name="desired_ip" value="<?= e((string)($metadata['desired_ip'] ?? '')) ?>" placeholder="<?= e((string)($host['ipv4_address'] ?? '')) ?>">
+          <select name="desired_ip" data-kea-ip-select data-selected-ip="<?= e($selectedIp) ?>">
-          <small class="muted">Wenn gesetzt, wird der Eintrag als KEA-Reservierung gespeichert.</small>
+            <option value="">Erst Gruppe waehlen</option>
+          </select>
+          <small class="muted">Es werden nur freie IPs aus dem IP-Bereich der gewaehlten Gruppe angeboten.</small>
         </label>
         <label class="setup-field kea-edit-form__wide">
           <span>Notizen</span>
@@ -151,5 +162,36 @@ $metadata = is_array($host['metadata'] ?? null) ? $host['metadata'] : [];
         </div>
       </form>
     </div>
+    <script>
+      (() => {
+        const ipsByGroup = <?= json_encode($availableIpsByGroup, JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE) ?>;
+        const groupSelect = document.querySelector('[data-kea-group-select]');
+        const ipSelect = document.querySelector('[data-kea-ip-select]');
+        if (!groupSelect || !ipSelect) {
+          return;
+        }
+        const selectedIp = ipSelect.dataset.selectedIp || '';
+        const renderIps = () => {
+          const ips = ipsByGroup[groupSelect.value] || [];
+          ipSelect.innerHTML = '';
+          const empty = document.createElement('option');
+          empty.value = '';
+          empty.textContent = groupSelect.value ? 'Keine feste IP' : 'Erst Gruppe waehlen';
+          ipSelect.appendChild(empty);
+          if (selectedIp && !ips.includes(selectedIp)) {
+            ips.unshift(selectedIp);
+          }
+          for (const ip of ips) {
+            const option = document.createElement('option');
+            option.value = ip;
+            option.textContent = ip;
+            option.selected = ip === selectedIp;
+            ipSelect.appendChild(option);
+          }
+        };
+        groupSelect.addEventListener('change', renderIps);
+        renderIps();
+      })();
+    </script>
   <?php endif; ?>
 </section>

modules/kea/pages/groups.php

@@ -0,0 +1,167 @@
+<?php
+use App\Database;
+use App\Repository\KeaHostMetadataRepository;
+use App\Repository\KeaHostRepository;
+
+$module = modules()->get('kea');
+$settings = modules()->settings('kea');
+$metadataFallback = is_array($module['metadata_db_defaults'] ?? null) ? $module['metadata_db_defaults'] : [];
+$metadataConfig = is_array($settings['metadata_db'] ?? null)
+    ? array_replace($metadataFallback, $settings['metadata_db'])
+    : $metadataFallback;
+$fallback = $module['db_defaults'] ?? [];
+$error = null;
+$notice = null;
+$groups = [];
+$availableIpsByGroup = [];
+
+try {
+    if (empty($metadataConfig['driver']) || empty($metadataConfig['dbname'])) {
+        throw new RuntimeException('Nexus DHCP Zusatzdatenbank ist nicht konfiguriert.');
+    }
+
+    $metadataRepo = new KeaHostMetadataRepository(Database::createFromArray($metadataConfig));
+    $metadataRepo->ensureSchema();
+
+    if ($_SERVER['REQUEST_METHOD'] === 'POST') {
+        $action = (string)($_POST['action'] ?? '');
+        if ($action === 'save_group') {
+            $metadataRepo->saveGroup((string)($_POST['name'] ?? ''), (string)($_POST['description'] ?? ''));
+            $notice = 'Gruppe gespeichert.';
+        } elseif ($action === 'add_range') {
+            $metadataRepo->addRange(
+                (string)($_POST['group_name'] ?? ''),
+                (string)($_POST['start_ip'] ?? ''),
+                (string)($_POST['end_ip'] ?? '')
+            );
+            $notice = 'IP-Bereich gespeichert.';
+        }
+    }
+
+    $groups = $metadataRepo->listGroupsWithRanges();
+    $keaRepo = new KeaHostRepository(modules()->modulePdo('kea', $fallback), $metadataRepo);
+    $availableIpsByGroup = $metadataRepo->availableIpsByGroup(
+        array_merge($keaRepo->usedIpAddresses(), $metadataRepo->desiredIps()),
+        4096
+    );
+} catch (Throwable $e) {
+    $error = $e->getMessage();
+}
+?>
+<section class="kea-page">
+  <div class="section-head">
+    <div>
+      <h2 class="section-title">KEA Gruppen</h2>
+      <p>Gruppen und IP-Bereiche fuer DHCP-Reservierungen.</p>
+    </div>
+    <a class="nav-link" href="/module/kea">Zurueck</a>
+  </div>
+
+  <?php if ($error): ?>
+    <div class="kea-message kea-message--error" role="alert">
+      <strong>Fehler</strong>
+      <p><?= e($error) ?></p>
+    </div>
+  <?php elseif ($notice): ?>
+    <div class="kea-message kea-message--success"><?= e($notice) ?></div>
+  <?php endif; ?>
+
+  <div class="kea-panel">
+    <div class="kea-panel__head">
+      <div>
+        <span class="pill">Gruppe</span>
+        <h3>Gruppe anlegen</h3>
+      </div>
+    </div>
+    <form method="post" class="kea-edit-form">
+      <input type="hidden" name="action" value="save_group">
+      <label class="setup-field">
+        <span>Name</span>
+        <input type="text" name="name" required>
+      </label>
+      <label class="setup-field">
+        <span>Beschreibung</span>
+        <input type="text" name="description">
+      </label>
+      <div class="setup-actions kea-edit-form__wide">
+        <button class="cta-button" type="submit">Gruppe speichern</button>
+      </div>
+    </form>
+  </div>
+
+  <div class="kea-panel">
+    <div class="kea-panel__head">
+      <div>
+        <span class="pill">IP-Bereich</span>
+        <h3>Bereich zuweisen</h3>
+      </div>
+    </div>
+    <form method="post" class="kea-edit-form">
+      <input type="hidden" name="action" value="add_range">
+      <label class="setup-field">
+        <span>Gruppe</span>
+        <select name="group_name" required>
+          <option value="">Bitte waehlen</option>
+          <?php foreach ($groups as $group): ?>
+            <option value="<?= e((string)$group['name']) ?>"><?= e((string)$group['name']) ?></option>
+          <?php endforeach; ?>
+        </select>
+      </label>
+      <label class="setup-field">
+        <span>Start-IP</span>
+        <input type="text" name="start_ip" placeholder="192.168.178.50" required>
+      </label>
+      <label class="setup-field">
+        <span>End-IP</span>
+        <input type="text" name="end_ip" placeholder="192.168.178.99" required>
+      </label>
+      <div class="setup-actions kea-edit-form__wide">
+        <button class="cta-button" type="submit">Bereich speichern</button>
+      </div>
+    </form>
+  </div>
+
+  <div class="kea-panel">
+    <div class="kea-panel__head">
+      <div>
+        <span class="pill">Uebersicht</span>
+        <h3>Gruppen und freie IPs</h3>
+      </div>
+    </div>
+    <div class="kea-table-wrap">
+      <table class="kea-table">
+        <thead>
+          <tr>
+            <th>Gruppe</th>
+            <th>Beschreibung</th>
+            <th>Bereiche</th>
+            <th>Freie IPs</th>
+          </tr>
+        </thead>
+        <tbody>
+          <?php if ($groups === []): ?>
+            <tr><td colspan="4" class="kea-empty">Noch keine Gruppen definiert.</td></tr>
+          <?php else: ?>
+            <?php foreach ($groups as $group): ?>
+              <?php $available = $availableIpsByGroup[(string)$group['name']] ?? []; ?>
+              <tr>
+                <td><?= e((string)$group['name']) ?></td>
+                <td><?= e((string)($group['description'] ?? '-')) ?></td>
+                <td>
+                  <?php if (($group['ranges'] ?? []) === []): ?>
+                    <span class="muted">Kein Bereich</span>
+                  <?php else: ?>
+                    <?php foreach ($group['ranges'] as $range): ?>
+                      <div class="mono"><?= e((string)$range['start_ip']) ?> - <?= e((string)$range['end_ip']) ?></div>
+                    <?php endforeach; ?>
+                  <?php endif; ?>
+                </td>
+                <td><?= e((string)count($available)) ?></td>
+              </tr>
+            <?php endforeach; ?>
+          <?php endif; ?>
+        </tbody>
+      </table>
+    </div>
+  </div>
+</section>

modules/kea/pages/index.php

@@ -20,6 +20,7 @@ $stats = [
     'reservations' => 0,
     'leases' => 0,
     'groups' => [],
+    'free_ips' => [],
 ];
 
 try {
@@ -48,6 +49,15 @@ try {
             $stats['groups'][$group] = ($stats['groups'][$group] ?? 0) + 1;
         }
     }
+    if ($metadataRepo !== null) {
+        $stats['free_ips'] = array_map(
+            static fn(array $ips): int => count($ips),
+            $metadataRepo->availableIpsByGroup(
+                array_merge($repo->usedIpAddresses(), $metadataRepo->desiredIps()),
+                4096
+            )
+        );
+    }
 } catch (\Exception $e) {
     $error = "Datenbankfehler: " . $e->getMessage();
 }

modules/kea/partials/dashboard.php

@@ -45,6 +45,10 @@
             <span class="stat-label">Gruppen</span>
             <span class="stat-value"><?= e((string)count($stats['groups'] ?? [])) ?></span>
         </div>
+        <div class="stat-card">
+            <span class="stat-label">Freie Gruppen-IPs</span>
+            <span class="stat-value"><?= e((string)array_sum($stats['free_ips'] ?? [])) ?></span>
+        </div>
     </div>
 
     <div class="kea-panel">

src/Repository/KeaHostMetadataRepository.php

@@ -33,6 +33,7 @@ final class KeaHostMetadataRepository
             );
             $this->ensureColumn('nexus_dhcp_host_meta', 'group_name', 'TEXT');
             $this->ensureColumn('nexus_dhcp_host_meta', 'desired_ip', 'TEXT');
+            $this->ensureGroupSchema($driver);
             return;
         }
 
@@ -56,6 +57,7 @@ final class KeaHostMetadataRepository
             );
             $this->ensureColumn('nexus_dhcp_host_meta', 'group_name', 'TEXT');
             $this->ensureColumn('nexus_dhcp_host_meta', 'desired_ip', 'TEXT');
+            $this->ensureGroupSchema($driver);
             return;
         }
 
@@ -79,6 +81,7 @@ final class KeaHostMetadataRepository
 
         $this->ensureColumn('nexus_dhcp_host_meta', 'group_name', 'TEXT');
         $this->ensureColumn('nexus_dhcp_host_meta', 'desired_ip', 'TEXT');
+        $this->ensureGroupSchema($driver);
     }
 
     public function findByHostIds(array $hostIds): array
@@ -183,19 +186,278 @@ final class KeaHostMetadataRepository
 
     public function listGroups(): array
     {
+        $groups = [];
+
+        if ($this->tableExists('nexus_dhcp_groups')) {
+            $stmt = $this->pdo->query("SELECT name FROM nexus_dhcp_groups ORDER BY name ASC");
+            foreach ($stmt->fetchAll(PDO::FETCH_ASSOC) as $row) {
+                $name = trim((string)($row['name'] ?? ''));
+                if ($name !== '') {
+                    $groups[] = $name;
+                }
+            }
+        }
+
         $stmt = $this->pdo->query(
             "SELECT DISTINCT group_name
              FROM nexus_dhcp_host_meta
-             WHERE group_name IS NOT NULL AND group_name <> ''
+             WHERE group_name IS NOT NULL AND group_name <> ''"
-             ORDER BY group_name ASC"
+        );
+        foreach ($stmt->fetchAll(PDO::FETCH_ASSOC) as $row) {
+            $name = trim((string)($row['group_name'] ?? ''));
+            if ($name !== '') {
+                $groups[] = $name;
+            }
+        }
+
+        sort($groups, SORT_NATURAL | SORT_FLAG_CASE);
+        return array_values(array_unique($groups));
+    }
+
+    public function listGroupsWithRanges(): array
+    {
+        if (!$this->tableExists('nexus_dhcp_groups')) {
+            return [];
+        }
+
+        $groups = [];
+        $stmt = $this->pdo->query(
+            "SELECT id, name, description
+             FROM nexus_dhcp_groups
+             ORDER BY name ASC"
+        );
+        foreach ($stmt->fetchAll(PDO::FETCH_ASSOC) as $row) {
+            $id = (int)$row['id'];
+            $groups[$id] = [
+                'id' => $id,
+                'name' => (string)$row['name'],
+                'description' => (string)($row['description'] ?? ''),
+                'ranges' => [],
+            ];
+        }
+
+        if ($groups !== [] && $this->tableExists('nexus_dhcp_group_ranges')) {
+            $stmt = $this->pdo->query(
+                "SELECT id, group_id, start_ip, end_ip
+                 FROM nexus_dhcp_group_ranges
+                 ORDER BY start_ip ASC"
+            );
+            foreach ($stmt->fetchAll(PDO::FETCH_ASSOC) as $row) {
+                $groupId = (int)$row['group_id'];
+                if (isset($groups[$groupId])) {
+                    $groups[$groupId]['ranges'][] = [
+                        'id' => (int)$row['id'],
+                        'start_ip' => (string)$row['start_ip'],
+                        'end_ip' => (string)$row['end_ip'],
+                    ];
+                }
+            }
+        }
+
+        return array_values($groups);
+    }
+
+    public function saveGroup(string $name, string $description = ''): void
+    {
+        $name = trim($name);
+        if ($name === '') {
+            throw new \RuntimeException('Gruppenname fehlt.');
+        }
+
+        $driver = (string)$this->pdo->getAttribute(PDO::ATTR_DRIVER_NAME);
+        if ($driver === 'pgsql' || $driver === 'sqlite') {
+            $sql = "INSERT INTO nexus_dhcp_groups (name, description, updated_at)
+                    VALUES (:name, :description, CURRENT_TIMESTAMP)
+                    ON CONFLICT(name) DO UPDATE SET
+                        description = excluded.description,
+                        updated_at = CURRENT_TIMESTAMP";
+        } else {
+            $sql = "INSERT INTO nexus_dhcp_groups (name, description, updated_at)
+                    VALUES (:name, :description, CURRENT_TIMESTAMP)
+                    ON DUPLICATE KEY UPDATE
+                        description = VALUES(description),
+                        updated_at = CURRENT_TIMESTAMP";
+        }
+
+        $stmt = $this->pdo->prepare($sql);
+        $stmt->execute([
+            'name' => $name,
+            'description' => $this->nullableString($description),
+        ]);
+    }
+
+    public function addRange(string $groupName, string $startIp, string $endIp): void
+    {
+        $groupName = trim($groupName);
+        $startIp = trim($startIp);
+        $endIp = trim($endIp);
+        if ($groupName === '' || !filter_var($startIp, FILTER_VALIDATE_IP, FILTER_FLAG_IPV4) || !filter_var($endIp, FILTER_VALIDATE_IP, FILTER_FLAG_IPV4)) {
+            throw new \RuntimeException('Gruppe oder IP-Bereich ist ungueltig.');
+        }
+
+        if (ip2long($startIp) > ip2long($endIp)) {
+            throw new \RuntimeException('Start-IP muss vor der End-IP liegen.');
+        }
+
+        $groupId = $this->groupIdByName($groupName);
+        if ($groupId <= 0) {
+            throw new \RuntimeException('Gruppe wurde nicht gefunden.');
+        }
+
+        $stmt = $this->pdo->prepare(
+            "INSERT INTO nexus_dhcp_group_ranges (group_id, start_ip, end_ip, updated_at)
+             VALUES (:group_id, :start_ip, :end_ip, CURRENT_TIMESTAMP)"
+        );
+        $stmt->execute([
+            'group_id' => $groupId,
+            'start_ip' => $startIp,
+            'end_ip' => $endIp,
+        ]);
+    }
+
+    public function availableIpsByGroup(array $usedIps, int $limitPerGroup = 512): array
+    {
+        $used = array_flip(array_filter(array_map('strval', $usedIps)));
+        $items = [];
+        foreach ($this->listGroupsWithRanges() as $group) {
+            $available = [];
+            foreach ($group['ranges'] as $range) {
+                $start = ip2long((string)$range['start_ip']);
+                $end = ip2long((string)$range['end_ip']);
+                if ($start === false || $end === false) {
+                    continue;
+                }
+                for ($ip = $start; $ip <= $end && count($available) < $limitPerGroup; $ip++) {
+                    $address = long2ip($ip);
+                    if ($address !== false && !isset($used[$address])) {
+                        $available[] = $address;
+                    }
+                }
+            }
+            $items[(string)$group['name']] = $available;
+        }
+
+        return $items;
+    }
+
+    public function desiredIps(): array
+    {
+        $stmt = $this->pdo->query(
+            "SELECT desired_ip
+             FROM nexus_dhcp_host_meta
+             WHERE desired_ip IS NOT NULL AND desired_ip <> ''"
         );
 
         return array_values(array_filter(array_map(
-            static fn(array $row): string => (string)($row['group_name'] ?? ''),
+            static fn(array $row): string => (string)($row['desired_ip'] ?? ''),
             $stmt->fetchAll(PDO::FETCH_ASSOC)
         )));
     }
 
+    private function ensureGroupSchema(string $driver): void
+    {
+        if ($driver === 'pgsql') {
+            $this->pdo->exec(
+                "CREATE TABLE IF NOT EXISTS nexus_dhcp_groups (
+                    id BIGSERIAL PRIMARY KEY,
+                    name TEXT NOT NULL UNIQUE,
+                    description TEXT,
+                    updated_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
+                )"
+            );
+            $this->pdo->exec(
+                "CREATE TABLE IF NOT EXISTS nexus_dhcp_group_ranges (
+                    id BIGSERIAL PRIMARY KEY,
+                    group_id BIGINT NOT NULL REFERENCES nexus_dhcp_groups(id) ON DELETE CASCADE,
+                    start_ip TEXT NOT NULL,
+                    end_ip TEXT NOT NULL,
+                    updated_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
+                )"
+            );
+            return;
+        }
+
+        if ($driver === 'sqlite') {
+            $this->pdo->exec(
+                "CREATE TABLE IF NOT EXISTS nexus_dhcp_groups (
+                    id INTEGER PRIMARY KEY AUTOINCREMENT,
+                    name TEXT NOT NULL UNIQUE,
+                    description TEXT,
+                    updated_at TEXT NOT NULL DEFAULT (datetime('now'))
+                )"
+            );
+            $this->pdo->exec(
+                "CREATE TABLE IF NOT EXISTS nexus_dhcp_group_ranges (
+                    id INTEGER PRIMARY KEY AUTOINCREMENT,
+                    group_id INTEGER NOT NULL,
+                    start_ip TEXT NOT NULL,
+                    end_ip TEXT NOT NULL,
+                    updated_at TEXT NOT NULL DEFAULT (datetime('now'))
+                )"
+            );
+            return;
+        }
+
+        $this->pdo->exec(
+            "CREATE TABLE IF NOT EXISTS nexus_dhcp_groups (
+                id BIGINT AUTO_INCREMENT PRIMARY KEY,
+                name VARCHAR(190) NOT NULL UNIQUE,
+                description TEXT,
+                updated_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP
+            )"
+        );
+        $this->pdo->exec(
+            "CREATE TABLE IF NOT EXISTS nexus_dhcp_group_ranges (
+                id BIGINT AUTO_INCREMENT PRIMARY KEY,
+                group_id BIGINT NOT NULL,
+                start_ip VARCHAR(45) NOT NULL,
+                end_ip VARCHAR(45) NOT NULL,
+                updated_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
+                INDEX idx_nexus_dhcp_group_ranges_group_id (group_id)
+            )"
+        );
+    }
+
+    private function groupIdByName(string $name): int
+    {
+        $stmt = $this->pdo->prepare('SELECT id FROM nexus_dhcp_groups WHERE name = :name LIMIT 1');
+        $stmt->execute(['name' => $name]);
+        return (int)$stmt->fetchColumn();
+    }
+
+    private function tableExists(string $table): bool
+    {
+        $driver = (string)$this->pdo->getAttribute(PDO::ATTR_DRIVER_NAME);
+
+        if ($driver === 'sqlite') {
+            $stmt = $this->pdo->prepare(
+                "SELECT 1 FROM sqlite_master WHERE type = 'table' AND name = :table LIMIT 1"
+            );
+            $stmt->execute(['table' => $table]);
+            return (bool)$stmt->fetchColumn();
+        }
+
+        if ($driver === 'pgsql') {
+            $stmt = $this->pdo->prepare(
+                "SELECT 1
+                 FROM information_schema.tables
+                 WHERE table_schema = current_schema()
+                   AND table_name = :table
+                 LIMIT 1"
+            );
+        } else {
+            $stmt = $this->pdo->prepare(
+                "SELECT 1
+                 FROM information_schema.tables
+                 WHERE table_schema = DATABASE()
+                   AND table_name = :table
+                 LIMIT 1"
+            );
+        }
+        $stmt->execute(['table' => $table]);
+        return (bool)$stmt->fetchColumn();
+    }
+
     private function ensureColumn(string $table, string $column, string $definition): void
     {
         if ($this->columnExists($table, $column)) {

src/Repository/KeaHostRepository.php

@@ -66,6 +66,14 @@ final class KeaHostRepository
         }
     }
 
+    public function usedIpAddresses(int $limit = 10000): array
+    {
+        return array_values(array_unique(array_filter(array_map(
+            static fn(array $host): string => (string)($host['ipv4_address'] ?? ''),
+            $this->findAll($limit)
+        ))));
+    }
+
     private function findReservations(int $limit): array
     {
         if (!$this->tableExists('hosts')) {