mod/dfrn_poll.php

   1 <?php
   2
   3 /**
   4  * @file mod/dfrn_poll.php
   5  */
   6
   7 use Friendica\App;
   8 use Friendica\Core\Logger;
   9 use Friendica\Core\System;
  10 use Friendica\Core\Session;
  11 use Friendica\Database\DBA;
  12 use Friendica\DI;
  13 use Friendica\Protocol\DFRN;
  14 use Friendica\Protocol\OStatus;
  15 use Friendica\Util\Network;
  16 use Friendica\Util\Strings;
  17 use Friendica\Util\XML;
  18
  19 function dfrn_poll_init(App $a)
  20 {
  21         DI::auth()->withSession($a);
  22
  23         $dfrn_id         =  $_GET['dfrn_id']         ?? '';
  24         $type            = ($_GET['type']            ?? '') ?: 'data';
  25         $last_update     =  $_GET['last_update']     ?? '';
  26         $destination_url =  $_GET['destination_url'] ?? '';
  27         $challenge       =  $_GET['challenge']       ?? '';
  28         $sec             =  $_GET['sec']             ?? '';
  29         $dfrn_version    = floatval(($_GET['dfrn_version'] ?? 0.0) ?: 2.0);
  30         $quiet                   = !empty($_GET['quiet']);
  31
  32         // Possibly it is an OStatus compatible server that requests a user feed
  33         $user_agent = $_SERVER['HTTP_USER_AGENT'] ?? '';
  34         if (($a->argc > 1) && ($dfrn_id == '') && !strstr($user_agent, 'Friendica')) {
  35                 $nickname = $a->argv[1];
  36                 header("Content-type: application/atom+xml");
  37                 echo OStatus::feed($nickname, $last_update, 10);
  38                 exit();
  39         }
  40
  41         $direction = -1;
  42
  43         if (strpos($dfrn_id, ':') == 1) {
  44                 $direction = intval(substr($dfrn_id, 0, 1));
  45                 $dfrn_id = substr($dfrn_id, 2);
  46         }
  47
  48         $hidewall = false;
  49
  50         if (($dfrn_id === '') && empty($_POST['dfrn_id'])) {
  51                 if (DI::config()->get('system', 'block_public') && !Session::isAuthenticated()) {
  52                         throw new \Friendica\Network\HTTPException\ForbiddenException();
  53                 }
  54
  55                 $user = '';
  56                 if ($a->argc > 1) {
  57                         $r = q("SELECT `hidewall`,`nickname` FROM `user` WHERE `user`.`nickname` = '%s' LIMIT 1",
  58                                 DBA::escape($a->argv[1])
  59                         );
  60                         if (!$r) {
  61                                 throw new \Friendica\Network\HTTPException\NotFoundException();
  62                         }
  63
  64                         $hidewall = ($r[0]['hidewall'] && !local_user());
  65
  66                         $user = $r[0]['nickname'];
  67                 }
  68
  69                 Logger::log('dfrn_poll: public feed request from ' . $_SERVER['REMOTE_ADDR'] . ' for ' . $user);
  70                 header("Content-type: application/atom+xml");
  71                 echo DFRN::feed('', $user, $last_update, 0, $hidewall);
  72                 exit();
  73         }
  74
  75         if (($type === 'profile') && (!strlen($sec))) {
  76                 $sql_extra = '';
  77                 switch ($direction) {
  78                         case -1:
  79                                 $sql_extra = sprintf(" AND ( `dfrn-id` = '%s' OR `issued-id` = '%s' ) ", DBA::escape($dfrn_id), DBA::escape($dfrn_id));
  80                                 $my_id = $dfrn_id;
  81                                 break;
  82                         case 0:
  83                                 $sql_extra = sprintf(" AND `issued-id` = '%s' AND `duplex` = 1 ", DBA::escape($dfrn_id));
  84                                 $my_id = '1:' . $dfrn_id;
  85                                 break;
  86                         case 1:
  87                                 $sql_extra = sprintf(" AND `dfrn-id` = '%s' AND `duplex` = 1 ", DBA::escape($dfrn_id));
  88                                 $my_id = '0:' . $dfrn_id;
  89                                 break;
  90                         default:
  91                                 DI::baseUrl()->redirect();
  92                                 break; // NOTREACHED
  93                 }
  94
  95                 $r = q("SELECT `contact`.*, `user`.`username`, `user`.`nickname`
  96                         FROM `contact` LEFT JOIN `user` ON `contact`.`uid` = `user`.`uid`
  97                         WHERE `contact`.`blocked` = 0 AND `contact`.`pending` = 0
  98                         AND `user`.`nickname` = '%s' $sql_extra LIMIT 1",
  99                         DBA::escape($a->argv[1])
 100                 );
 101
 102                 if (DBA::isResult($r)) {
 103                         $s = Network::fetchUrl($r[0]['poll'] . '?dfrn_id=' . $my_id . '&type=profile-check');
 104
 105                         Logger::log("dfrn_poll: old profile returns " . $s, Logger::DATA);
 106
 107                         if (strlen($s)) {
 108                                 $xml = XML::parseString($s);
 109
 110                                 if ((int)$xml->status === 1) {
 111                                         $_SESSION['authenticated'] = 1;
 112                                         $_SESSION['visitor_id'] = $r[0]['id'];
 113                                         $_SESSION['visitor_home'] = $r[0]['url'];
 114                                         $_SESSION['visitor_handle'] = $r[0]['addr'];
 115                                         $_SESSION['visitor_visiting'] = $r[0]['uid'];
 116                                         $_SESSION['my_url'] = $r[0]['url'];
 117
 118                                         Session::setVisitorsContacts();
 119
 120                                         if (!$quiet) {
 121                                                 info(DI::l10n()->t('%1$s welcomes %2$s', $r[0]['username'], $r[0]['name']) . EOL);
 122                                         }
 123
 124                                         // Visitors get 1 day session.
 125                                         $session_id = session_id();
 126                                         $expire = time() + 86400;
 127                                         q("UPDATE `session` SET `expire` = '%s' WHERE `sid` = '%s'",
 128                                                 DBA::escape($expire),
 129                                                 DBA::escape($session_id)
 130                                         );
 131                                 }
 132                         }
 133
 134                         $profile = (count($r) > 0 && isset($r[0]['nickname']) ? $r[0]['nickname'] : '');
 135                         if (!empty($destination_url)) {
 136                                 System::externalRedirect($destination_url);
 137                         } else {
 138                                 DI::baseUrl()->redirect('profile/' . $profile);
 139                         }
 140                 }
 141                 DI::baseUrl()->redirect();
 142         }
 143
 144         if ($type === 'profile-check' && $dfrn_version < 2.2) {
 145                 if ((strlen($challenge)) && (strlen($sec))) {
 146                         DBA::delete('profile_check', ["`expire` < ?", time()]);
 147                         $r = q("SELECT * FROM `profile_check` WHERE `sec` = '%s' ORDER BY `expire` DESC LIMIT 1",
 148                                 DBA::escape($sec)
 149                         );
 150                         if (!DBA::isResult($r)) {
 151                                 System::xmlExit(3, 'No ticket');
 152                                 // NOTREACHED
 153                         }
 154
 155                         $orig_id = $r[0]['dfrn_id'];
 156                         if (strpos($orig_id, ':')) {
 157                                 $orig_id = substr($orig_id, 2);
 158                         }
 159
 160                         $c = q("SELECT * FROM `contact` WHERE `id` = %d LIMIT 1",
 161                                 intval($r[0]['cid'])
 162                         );
 163                         if (!DBA::isResult($c)) {
 164                                 System::xmlExit(3, 'No profile');
 165                         }
 166
 167                         $contact = $c[0];
 168
 169                         $sent_dfrn_id = hex2bin($dfrn_id);
 170                         $challenge = hex2bin($challenge);
 171
 172                         $final_dfrn_id = '';
 173
 174                         if (($contact['duplex']) && strlen($contact['prvkey'])) {
 175                                 openssl_private_decrypt($sent_dfrn_id, $final_dfrn_id, $contact['prvkey']);
 176                                 openssl_private_decrypt($challenge, $decoded_challenge, $contact['prvkey']);
 177                         } else {
 178                                 openssl_public_decrypt($sent_dfrn_id, $final_dfrn_id, $contact['pubkey']);
 179                                 openssl_public_decrypt($challenge, $decoded_challenge, $contact['pubkey']);
 180                         }
 181
 182                         $final_dfrn_id = substr($final_dfrn_id, 0, strpos($final_dfrn_id, '.'));
 183
 184                         if (strpos($final_dfrn_id, ':') == 1) {
 185                                 $final_dfrn_id = substr($final_dfrn_id, 2);
 186                         }
 187
 188                         if ($final_dfrn_id != $orig_id) {
 189                                 Logger::log('profile_check: ' . $final_dfrn_id . ' != ' . $orig_id, Logger::DEBUG);
 190                                 // did not decode properly - cannot trust this site
 191                                 System::xmlExit(3, 'Bad decryption');
 192                         }
 193
 194                         header("Content-type: text/xml");
 195                         echo "<?xml version=\"1.0\" encoding=\"UTF-8\"?><dfrn_poll><status>0</status><challenge>$decoded_challenge</challenge><sec>$sec</sec></dfrn_poll>";
 196                         exit();
 197                         // NOTREACHED
 198                 } else {
 199                         // old protocol
 200                         switch ($direction) {
 201                                 case 1:
 202                                         $dfrn_id = '0:' . $dfrn_id;
 203                                         break;
 204                                 case 0:
 205                                         $dfrn_id = '1:' . $dfrn_id;
 206                                         break;
 207                                 default:
 208                                         break;
 209                         }
 210
 211                         DBA::delete('profile_check', ["`expire` < ?", time()]);
 212                         $r = q("SELECT * FROM `profile_check` WHERE `dfrn_id` = '%s' ORDER BY `expire` DESC",
 213                                 DBA::escape($dfrn_id));
 214                         if (DBA::isResult($r)) {
 215                                 System::xmlExit(1);
 216                                 return; // NOTREACHED
 217                         }
 218                         System::xmlExit(0);
 219                         return; // NOTREACHED
 220                 }
 221         }
 222 }
 223
 224 function dfrn_poll_post(App $a)
 225 {
 226         $dfrn_id      =  $_POST['dfrn_id']   ?? '';
 227         $challenge    =  $_POST['challenge'] ?? '';
 228         $url          =  $_POST['url']       ?? '';
 229         $sec          =  $_POST['sec']       ?? '';
 230         $ptype        =  $_POST['type']      ?? '';
 231         $perm         = ($_POST['perm']      ?? '') ?: 'r';
 232         $dfrn_version = floatval(($_GET['dfrn_version'] ?? 0.0) ?: 2.0);
 233
 234         if ($ptype === 'profile-check') {
 235                 if (strlen($challenge) && strlen($sec)) {
 236                         Logger::log('dfrn_poll: POST: profile-check');
 237
 238                         DBA::delete('profile_check', ["`expire` < ?", time()]);
 239                         $r = q("SELECT * FROM `profile_check` WHERE `sec` = '%s' ORDER BY `expire` DESC LIMIT 1",
 240                                 DBA::escape($sec)
 241                         );
 242                         if (!DBA::isResult($r)) {
 243                                 System::xmlExit(3, 'No ticket');
 244                                 // NOTREACHED
 245                         }
 246
 247                         $orig_id = $r[0]['dfrn_id'];
 248                         if (strpos($orig_id, ':')) {
 249                                 $orig_id = substr($orig_id, 2);
 250                         }
 251
 252                         $c = q("SELECT * FROM `contact` WHERE `id` = %d LIMIT 1",
 253                                 intval($r[0]['cid'])
 254                         );
 255                         if (!DBA::isResult($c)) {
 256                                 System::xmlExit(3, 'No profile');
 257                         }
 258
 259                         $contact = $c[0];
 260
 261                         $sent_dfrn_id = hex2bin($dfrn_id);
 262                         $challenge = hex2bin($challenge);
 263
 264                         $final_dfrn_id = '';
 265
 266                         if ($contact['duplex'] && strlen($contact['prvkey'])) {
 267                                 openssl_private_decrypt($sent_dfrn_id, $final_dfrn_id, $contact['prvkey']);
 268                                 openssl_private_decrypt($challenge, $decoded_challenge, $contact['prvkey']);
 269                         } else {
 270                                 openssl_public_decrypt($sent_dfrn_id, $final_dfrn_id, $contact['pubkey']);
 271                                 openssl_public_decrypt($challenge, $decoded_challenge, $contact['pubkey']);
 272                         }
 273
 274                         $final_dfrn_id = substr($final_dfrn_id, 0, strpos($final_dfrn_id, '.'));
 275
 276                         if (strpos($final_dfrn_id, ':') == 1) {
 277                                 $final_dfrn_id = substr($final_dfrn_id, 2);
 278                         }
 279
 280                         if ($final_dfrn_id != $orig_id) {
 281                                 Logger::log('profile_check: ' . $final_dfrn_id . ' != ' . $orig_id, Logger::DEBUG);
 282                                 // did not decode properly - cannot trust this site
 283                                 System::xmlExit(3, 'Bad decryption');
 284                         }
 285
 286                         header("Content-type: text/xml");
 287                         echo "<?xml version=\"1.0\" encoding=\"UTF-8\"?><dfrn_poll><status>0</status><challenge>$decoded_challenge</challenge><sec>$sec</sec></dfrn_poll>";
 288                         exit();
 289                         // NOTREACHED
 290                 }
 291         }
 292
 293         $direction = -1;
 294         if (strpos($dfrn_id, ':') == 1) {
 295                 $direction = intval(substr($dfrn_id, 0, 1));
 296                 $dfrn_id = substr($dfrn_id, 2);
 297         }
 298
 299         $r = q("SELECT * FROM `challenge` WHERE `dfrn-id` = '%s' AND `challenge` = '%s' LIMIT 1",
 300                 DBA::escape($dfrn_id),
 301                 DBA::escape($challenge)
 302         );
 303
 304         if (!DBA::isResult($r)) {
 305                 exit();
 306         }
 307
 308         $type = $r[0]['type'];
 309         $last_update = $r[0]['last_update'];
 310
 311         DBA::delete('challenge', ['dfrn-id' => $dfrn_id, 'challenge' => $challenge]);
 312
 313         $sql_extra = '';
 314         switch ($direction) {
 315                 case -1:
 316                         $sql_extra = sprintf(" AND `issued-id` = '%s' ", DBA::escape($dfrn_id));
 317                         break;
 318                 case 0:
 319                         $sql_extra = sprintf(" AND `issued-id` = '%s' AND `duplex` = 1 ", DBA::escape($dfrn_id));
 320                         break;
 321                 case 1:
 322                         $sql_extra = sprintf(" AND `dfrn-id` = '%s' AND `duplex` = 1 ", DBA::escape($dfrn_id));
 323                         break;
 324                 default:
 325                         DI::baseUrl()->redirect();
 326                         break; // NOTREACHED
 327         }
 328
 329         $r = q("SELECT * FROM `contact` WHERE `blocked` = 0 AND `pending` = 0 $sql_extra LIMIT 1");
 330         if (!DBA::isResult($r)) {
 331                 exit();
 332         }
 333
 334         $contact = $r[0];
 335         $owner_uid = $r[0]['uid'];
 336         $contact_id = $r[0]['id'];
 337
 338         if ($type === 'reputation' && strlen($url)) {
 339                 $r = q("SELECT * FROM `contact` WHERE `url` = '%s' AND `uid` = %d LIMIT 1",
 340                         DBA::escape($url),
 341                         intval($owner_uid)
 342                 );
 343                 $reputation = 0;
 344                 $text = '';
 345
 346                 if (DBA::isResult($r)) {
 347                         $reputation = $r[0]['rating'];
 348                         $text = $r[0]['reason'];
 349
 350                         if ($r[0]['id'] == $contact_id) { // inquiring about own reputation not allowed
 351                                 $reputation = 0;
 352                                 $text = '';
 353                         }
 354                 }
 355
 356                 echo "<?xml version=\"1.0\" encoding=\"UTF-8\"?>
 357                 <reputation>
 358                         <url>$url</url>
 359                         <rating>$reputation</rating>
 360                         <description>$text</description>
 361                 </reputation>
 362                 ";
 363                 exit();
 364                 // NOTREACHED
 365         } else {
 366                 // Update the writable flag if it changed
 367                 Logger::log('dfrn_poll: post request feed: ' . print_r($_POST, true), Logger::DATA);
 368                 if ($dfrn_version >= 2.21) {
 369                         if ($perm === 'rw') {
 370                                 $writable = 1;
 371                         } else {
 372                                 $writable = 0;
 373                         }
 374
 375                         if ($writable != $contact['writable']) {
 376                                 q("UPDATE `contact` SET `writable` = %d WHERE `id` = %d",
 377                                         intval($writable),
 378                                         intval($contact_id)
 379                                 );
 380                         }
 381                 }
 382
 383                 header("Content-type: application/atom+xml");
 384                 $o = DFRN::feed($dfrn_id, $a->argv[1], $last_update, $direction);
 385                 echo $o;
 386                 exit();
 387         }
 388 }
 389
 390 function dfrn_poll_content(App $a)
 391 {
 392         $dfrn_id         =  $_GET['dfrn_id']         ?? '';
 393         $type            = ($_GET['type']            ?? '') ?: 'data';
 394         $last_update     =  $_GET['last_update']     ?? '';
 395         $destination_url =  $_GET['destination_url'] ?? '';
 396         $sec             =  $_GET['sec']             ?? '';
 397         $dfrn_version    = floatval(($_GET['dfrn_version'] ?? 0.0) ?: 2.0);
 398         $quiet           = !empty($_GET['quiet']);
 399
 400         $direction = -1;
 401         if (strpos($dfrn_id, ':') == 1) {
 402                 $direction = intval(substr($dfrn_id, 0, 1));
 403                 $dfrn_id = substr($dfrn_id, 2);
 404         }
 405
 406         if ($dfrn_id != '') {
 407                 // initial communication from external contact
 408                 $hash = Strings::getRandomHex();
 409
 410                 $status = 0;
 411
 412                 DBA::delete('challenge', ["`expire` < ?", time()]);
 413
 414                 if ($type !== 'profile') {
 415                         q("INSERT INTO `challenge` ( `challenge`, `dfrn-id`, `expire` , `type`, `last_update` )
 416                                 VALUES( '%s', '%s', '%s', '%s', '%s' ) ",
 417                                 DBA::escape($hash),
 418                                 DBA::escape($dfrn_id),
 419                                 intval(time() + 60 ),
 420                                 DBA::escape($type),
 421                                 DBA::escape($last_update)
 422                         );
 423                 }
 424
 425                 $sql_extra = '';
 426                 switch ($direction) {
 427                         case -1:
 428                                 if ($type === 'profile') {
 429                                         $sql_extra = sprintf(" AND (`dfrn-id` = '%s' OR `issued-id` = '%s') ", DBA::escape($dfrn_id), DBA::escape($dfrn_id));
 430                                 } else {
 431                                         $sql_extra = sprintf(" AND `issued-id` = '%s' ", DBA::escape($dfrn_id));
 432                                 }
 433
 434                                 $my_id = $dfrn_id;
 435                                 break;
 436                         case 0:
 437                                 $sql_extra = sprintf(" AND `issued-id` = '%s' AND `duplex` = 1 ", DBA::escape($dfrn_id));
 438                                 $my_id = '1:' . $dfrn_id;
 439                                 break;
 440                         case 1:
 441                                 $sql_extra = sprintf(" AND `dfrn-id` = '%s' AND `duplex` = 1 ", DBA::escape($dfrn_id));
 442                                 $my_id = '0:' . $dfrn_id;
 443                                 break;
 444                         default:
 445                                 DI::baseUrl()->redirect();
 446                                 break; // NOTREACHED
 447                 }
 448
 449                 $nickname = $a->argv[1];
 450
 451                 $r = q("SELECT `contact`.*, `user`.`username`, `user`.`nickname`
 452                         FROM `contact` LEFT JOIN `user` ON `contact`.`uid` = `user`.`uid`
 453                         WHERE `contact`.`blocked` = 0 AND `contact`.`pending` = 0
 454                         AND `user`.`nickname` = '%s' $sql_extra LIMIT 1",
 455                         DBA::escape($nickname)
 456                 );
 457                 if (DBA::isResult($r)) {
 458                         $challenge = '';
 459                         $encrypted_id = '';
 460                         $id_str = $my_id . '.' . mt_rand(1000, 9999);
 461
 462                         if (($r[0]['duplex'] && strlen($r[0]['pubkey'])) || !strlen($r[0]['prvkey'])) {
 463                                 openssl_public_encrypt($hash, $challenge, $r[0]['pubkey']);
 464                                 openssl_public_encrypt($id_str, $encrypted_id, $r[0]['pubkey']);
 465                         } else {
 466                                 openssl_private_encrypt($hash, $challenge, $r[0]['prvkey']);
 467                                 openssl_private_encrypt($id_str, $encrypted_id, $r[0]['prvkey']);
 468                         }
 469
 470                         $challenge = bin2hex($challenge);
 471                         $encrypted_id = bin2hex($encrypted_id);
 472                 } else {
 473                         $status = 1;
 474                         $challenge = '';
 475                         $encrypted_id = '';
 476                 }
 477
 478                 if (($type === 'profile') && (strlen($sec))) {
 479                         // heluecht: I don't know why we don't fail immediately when the user or contact hadn't been found.
 480                         // Since it doesn't make sense to continue from this point on, we now fail here. This should be safe.
 481                         if (!DBA::isResult($r)) {
 482                                 throw new \Friendica\Network\HTTPException\NotFoundException();
 483                         }
 484
 485                         // URL reply
 486                         if ($dfrn_version < 2.2) {
 487                                 $s = Network::fetchUrl($r[0]['poll']
 488                                         . '?dfrn_id=' . $encrypted_id
 489                                         . '&type=profile-check'
 490                                         . '&dfrn_version=' . DFRN_PROTOCOL_VERSION
 491                                         . '&challenge=' . $challenge
 492                                         . '&sec=' . $sec
 493                                 );
 494                         } else {
 495                                 $s = Network::post($r[0]['poll'], [
 496                                         'dfrn_id' => $encrypted_id,
 497                                         'type' => 'profile-check',
 498                                         'dfrn_version' => DFRN_PROTOCOL_VERSION,
 499                                         'challenge' => $challenge,
 500                                         'sec' => $sec
 501                                 ])->getBody();
 502                         }
 503
 504                         Logger::log("dfrn_poll: sec profile: " . $s, Logger::DATA);
 505
 506                         if (strlen($s) && strstr($s, '<?xml')) {
 507                                 $xml = XML::parseString($s);
 508
 509                                 Logger::log('dfrn_poll: profile: parsed xml: ' . print_r($xml, true), Logger::DATA);
 510
 511                                 Logger::log('dfrn_poll: secure profile: challenge: ' . $xml->challenge . ' expecting ' . $hash);
 512                                 Logger::log('dfrn_poll: secure profile: sec: ' . $xml->sec . ' expecting ' . $sec);
 513
 514                                 if (((int) $xml->status == 0) && ($xml->challenge == $hash) && ($xml->sec == $sec)) {
 515                                         $_SESSION['authenticated'] = 1;
 516                                         $_SESSION['visitor_id'] = $r[0]['id'];
 517                                         $_SESSION['visitor_home'] = $r[0]['url'];
 518                                         $_SESSION['visitor_visiting'] = $r[0]['uid'];
 519                                         $_SESSION['my_url'] = $r[0]['url'];
 520
 521                                         Session::setVisitorsContacts();
 522
 523                                         if (!$quiet) {
 524                                                 info(DI::l10n()->t('%1$s welcomes %2$s', $r[0]['username'], $r[0]['name']) . EOL);
 525                                         }
 526
 527                                         // Visitors get 1 day session.
 528                                         $session_id = session_id();
 529                                         $expire = time() + 86400;
 530                                         q("UPDATE `session` SET `expire` = '%s' WHERE `sid` = '%s'",
 531                                                 DBA::escape($expire),
 532                                                 DBA::escape($session_id)
 533                                         );
 534                                 }
 535                         }
 536
 537                         $profile = ((DBA::isResult($r) && $r[0]['nickname']) ? $r[0]['nickname'] : $nickname);
 538
 539                         switch ($destination_url) {
 540                                 case 'profile':
 541                                         DI::baseUrl()->redirect('profile/' . $profile . '?tab=profile');
 542                                         break;
 543                                 case 'photos':
 544                                         DI::baseUrl()->redirect('photos/' . $profile);
 545                                         break;
 546                                 case 'status':
 547                                 case '':
 548                                         DI::baseUrl()->redirect('profile/' . $profile);
 549                                         break;
 550                                 default:
 551                                         $appendix = (strstr($destination_url, '?') ? '&redir=1' : '?redir=1');
 552                                         DI::baseUrl()->redirect($destination_url . $appendix);
 553                                         break;
 554                         }
 555                         // NOTREACHED
 556                 } else {
 557                         // XML reply
 558                         header("Content-type: text/xml");
 559                         echo '<?xml version="1.0" encoding="UTF-8"?>' . "\r\n"
 560                                 . '<dfrn_poll>' . "\r\n"
 561                                 . "\t" . '<status>' . $status . '</status>' . "\r\n"
 562                                 . "\t" . '<dfrn_version>' . DFRN_PROTOCOL_VERSION . '</dfrn_version>' . "\r\n"
 563                                 . "\t" . '<dfrn_id>' . $encrypted_id . '</dfrn_id>' . "\r\n"
 564                                 . "\t" . '<challenge>' . $challenge . '</challenge>' . "\r\n"
 565                                 . '</dfrn_poll>' . "\r\n";
 566                         exit();
 567                         // NOTREACHED
 568                 }
 569         }
 570 }