Add option to do not register ipv6 link-local addresses in the DNS Resolver, see #1400

src/etc/inc/plugins.inc.d/unbound.inc

@@ -572,10 +572,12 @@ function unbound_add_host_entries()
                 $unbound_entries .= "local-data: \"{$config['system']['hostname']}.{$config['system']['domain']} AAAA {$laddr6}\"\n";
                 $unbound_entries .= "local-data: \"{$config['system']['hostname']} AAAA {$laddr6}\"\n";
             }
-            $lladdr6 = find_interface_ipv6_ll($if);
-            if (is_ipaddrv6($lladdr6)) {
-                $unbound_entries .= "local-data: \"{$config['system']['hostname']}.{$config['system']['domain']} AAAA {$lladdr6}\"\n";
-                $unbound_entries .= "local-data: \"{$config['system']['hostname']} AAAA {$lladdr6}\"\n";
+            if (!isset($config['unbound']['reglladdr6'])) {
+                $lladdr6 = find_interface_ipv6_ll($if);
+                if (is_ipaddrv6($lladdr6)) {
+                    $unbound_entries .= "local-data: \"{$config['system']['hostname']}.{$config['system']['domain']} AAAA {$lladdr6}\"\n";
+                    $unbound_entries .= "local-data: \"{$config['system']['hostname']} AAAA {$lladdr6}\"\n";
+                }
             }
         }
     }

src/www/services_unbound.php

@@ -43,6 +43,7 @@ if ($_SERVER['REQUEST_METHOD'] === 'GET') {
     $pconfig['enable'] = isset($a_unboundcfg['enable']);
     $pconfig['dnssec'] = isset($a_unboundcfg['dnssec']);
     $pconfig['forwarding'] = isset($a_unboundcfg['forwarding']);
+    $pconfig['reglladdr6'] = isset($a_unboundcfg['reglladdr6']);
     $pconfig['regdhcp'] = isset($a_unboundcfg['regdhcp']);
     $pconfig['regdhcpstatic'] = isset($a_unboundcfg['regdhcpstatic']);
     $pconfig['txtsupport'] = isset($a_unboundcfg['txtsupport']);
@@ -102,6 +103,7 @@ if ($_SERVER['REQUEST_METHOD'] === 'GET') {
             $a_unboundcfg['enable'] = !empty($pconfig['enable']);
             $a_unboundcfg['dnssec'] = !empty($pconfig['dnssec']);
             $a_unboundcfg['forwarding'] = !empty($pconfig['forwarding']);
+            $a_unboundcfg['reglladdr6'] = !empty($pconfig['reglladdr6']);
             $a_unboundcfg['regdhcp'] = !empty($pconfig['regdhcp']);
             $a_unboundcfg['regdhcpstatic'] = !empty($pconfig['regdhcpstatic']);
             $a_unboundcfg['txtsupport'] = !empty($pconfig['txtsupport']);
@@ -255,6 +257,19 @@ include_once("head.inc");
                           </div>
                         </td>
                       </tr>
+                      <tr>
+                        <td><a id="help_for_reglladdr6" href="#" class="showhelp"><i class="fa fa-info-circle"></i></a> <?=gettext("Disable Link-local Address Registration");?></td>
+                        <td>
+                          <input name="reglladdr6" type="checkbox" id="reglladdr6" value="yes" <?=!empty($pconfig['reglladdr6']) ? "checked=\"checked\"" : "";?> />
+                          <strong><?=gettext("Disable registration of link-local addresses in the DNS Resolver");?></strong>
+                          <div class="hidden" for="help_for_reglladdr6">
+                            <?= gettext("If this option is set, then IPv6 link-local " .
+                            "addresses will not be registered in the DNS Resolver, preventing " .
+                            "return of unreachable address from the DNS resolver when more " .
+                            "than one listen interface is configured."); ?>
+                          </div>
+                        </td>
+                      </tr>
                       <tr>
                         <td><i class="fa fa-info-circle text-muted"></i> <?=gettext("Advanced");?></td>
                         <td>