Revert "interfaces: the PPP uptime option no longer exists"

This reverts commit b4cca4ef5a.

Meh: apparently all of this works but is never read.

src/etc/inc/interfaces.inc

@@ -1329,6 +1329,13 @@ EOD;
     /* write the configuration */
     @file_put_contents("/var/etc/mpd_{$interface}.conf", $mpdconf);
 
+    /* create the uptime log if requested */
+    if (isset($ppp['uptime'])) {
+        @touch("/conf/{$ifcfg['if']}.log");
+    } else {
+        @unlink("/conf/{$ifcfg['if']}.log");
+    }
+
     /* clean up old lock files */
     foreach ($ports as $port) {
         @unlink('/var/spool/lock/LCK..' . basename($port));

src/www/interfaces_ppps_edit.php

@@ -101,7 +101,7 @@ if ($_SERVER['REQUEST_METHOD'] === 'GET') {
         $id = $_GET['id'];
     }
     // plain 1-on-1 copy
-    $copy_fields = array('ptpid', 'type', 'username', 'idletimeout', 'descr', 'simpin', 'pin-wait',
+    $copy_fields = array('ptpid', 'type', 'username', 'idletimeout', 'uptime', 'descr', 'simpin', 'pin-wait',
                         'apn', 'apnum', 'phone', 'connect-timeout', 'provider', 'hostuniq');
     foreach ($copy_fields as $fieldname) {
         if (isset($a_ppps[$id][$fieldname])) {
@@ -220,6 +220,7 @@ if ($_SERVER['REQUEST_METHOD'] === 'GET') {
         if (!empty($pconfig['idletimeout'])) {
             $ppp['idletimeout'] = $pconfig['idletimeout'];
         }
+        $ppp['uptime'] = !empty($pconfig['uptime']);
         if (!empty($pconfig['descr'])) {
             $ppp['descr'] = $pconfig['descr'];
         }
@@ -712,6 +713,16 @@ include("head.inc");
                           </div>
                         </td>
                       </tr>
+                      <tr style="display:none" class="act_show_advanced">
+                        <td><a id="help_for_uptime" href="#" class="showhelp"><i class="fa fa-info-circle"></i></a> <?= gettext("Uptime Logging"); ?></td>
+                        <td>
+                          <input type="checkbox" value="on" id="uptime" name="uptime" <?=!empty($pconfig['uptime']) ? "checked=\"checked\"" : ""; ?> />
+                          <?= gettext("Enable persistent logging of connection uptime."); ?>
+                          <div class="hidden" data-for="help_for_uptime">
+                            <?= gettext("This option causes cumulative uptime to be recorded and displayed on the Status Interfaces page."); ?>
+                          </div>
+                        </td>
+                      </tr>
                     </tbody>
                   </table>
                   <!-- Advanced (all) -->