mod/dfrn_poll.php

   1 <?php
   2
   3 /**
   4  * @file mod/dfrn_poll.php
   5  */
   6
   7 use Friendica\App;
   8 use Friendica\Core\Config;
   9 use Friendica\Core\L10n;
  10 use Friendica\Core\Logger;
  11 use Friendica\Core\System;
  12 use Friendica\Database\DBA;
  13 use Friendica\Module\Login;
  14 use Friendica\Protocol\DFRN;
  15 use Friendica\Protocol\OStatus;
  16 use Friendica\Util\Network;
  17 use Friendica\Util\Strings;
  18 use Friendica\Util\XML;
  19
  20 function dfrn_poll_init(App $a)
  21 {
  22         Login::sessionAuth();
  23
  24         $dfrn_id         = defaults($_GET, 'dfrn_id'        , '');
  25         $type            = defaults($_GET, 'type'           , 'data');
  26         $last_update     = defaults($_GET, 'last_update'    , '');
  27         $destination_url = defaults($_GET, 'destination_url', '');
  28         $challenge       = defaults($_GET, 'challenge'      , '');
  29         $sec             = defaults($_GET, 'sec'            , '');
  30         $dfrn_version    = (float) defaults($_GET, 'dfrn_version'   , 2.0);
  31         $perm            = defaults($_GET, 'perm'           , 'r');
  32         $quiet                   = !empty($_GET['quiet']);
  33
  34         // Possibly it is an OStatus compatible server that requests a user feed
  35         $user_agent = defaults($_SERVER, 'HTTP_USER_AGENT', '');
  36         if (($a->argc > 1) && ($dfrn_id == '') && !strstr($user_agent, 'Friendica')) {
  37                 $nickname = $a->argv[1];
  38                 header("Content-type: application/atom+xml");
  39                 echo OStatus::feed($nickname, $last_update, 10);
  40                 exit();
  41         }
  42
  43         $direction = -1;
  44
  45         if (strpos($dfrn_id, ':') == 1) {
  46                 $direction = intval(substr($dfrn_id, 0, 1));
  47                 $dfrn_id = substr($dfrn_id, 2);
  48         }
  49
  50         $hidewall = false;
  51
  52         if (($dfrn_id === '') && empty($_POST['dfrn_id'])) {
  53                 if (Config::get('system', 'block_public') && !local_user() && !remote_user()) {
  54                         System::httpExit(403);
  55                 }
  56
  57                 $user = '';
  58                 if ($a->argc > 1) {
  59                         $r = q("SELECT `hidewall`,`nickname` FROM `user` WHERE `user`.`nickname` = '%s' LIMIT 1",
  60                                 DBA::escape($a->argv[1])
  61                         );
  62                         if (!$r) {
  63                                 System::httpExit(404);
  64                         }
  65
  66                         $hidewall = ($r[0]['hidewall'] && !local_user());
  67
  68                         $user = $r[0]['nickname'];
  69                 }
  70
  71                 Logger::log('dfrn_poll: public feed request from ' . $_SERVER['REMOTE_ADDR'] . ' for ' . $user);
  72                 header("Content-type: application/atom+xml");
  73                 echo DFRN::feed('', $user, $last_update, 0, $hidewall);
  74                 exit();
  75         }
  76
  77         if (($type === 'profile') && (!strlen($sec))) {
  78                 $sql_extra = '';
  79                 switch ($direction) {
  80                         case -1:
  81                                 $sql_extra = sprintf(" AND ( `dfrn-id` = '%s' OR `issued-id` = '%s' ) ", DBA::escape($dfrn_id), DBA::escape($dfrn_id));
  82                                 $my_id = $dfrn_id;
  83                                 break;
  84                         case 0:
  85                                 $sql_extra = sprintf(" AND `issued-id` = '%s' AND `duplex` = 1 ", DBA::escape($dfrn_id));
  86                                 $my_id = '1:' . $dfrn_id;
  87                                 break;
  88                         case 1:
  89                                 $sql_extra = sprintf(" AND `dfrn-id` = '%s' AND `duplex` = 1 ", DBA::escape($dfrn_id));
  90                                 $my_id = '0:' . $dfrn_id;
  91                                 break;
  92                         default:
  93                                 $a->internalRedirect();
  94                                 break; // NOTREACHED
  95                 }
  96
  97                 $r = q("SELECT `contact`.*, `user`.`username`, `user`.`nickname`
  98                         FROM `contact` LEFT JOIN `user` ON `contact`.`uid` = `user`.`uid`
  99                         WHERE `contact`.`blocked` = 0 AND `contact`.`pending` = 0
 100                         AND `user`.`nickname` = '%s' $sql_extra LIMIT 1",
 101                         DBA::escape($a->argv[1])
 102                 );
 103
 104                 if (DBA::isResult($r)) {
 105                         $s = Network::fetchUrl($r[0]['poll'] . '?dfrn_id=' . $my_id . '&type=profile-check');
 106
 107                         Logger::log("dfrn_poll: old profile returns " . $s, Logger::DATA);
 108
 109                         if (strlen($s)) {
 110                                 $xml = XML::parseString($s);
 111
 112                                 if ((int)$xml->status === 1) {
 113                                         $_SESSION['authenticated'] = 1;
 114                                         if (empty($_SESSION['remote'])) {
 115                                                 $_SESSION['remote'] = [];
 116                                         }
 117
 118                                         $_SESSION['remote'][] = ['cid' => $r[0]['id'], 'uid' => $r[0]['uid'], 'url' => $r[0]['url']];
 119
 120                                         $_SESSION['visitor_id'] = $r[0]['id'];
 121                                         $_SESSION['visitor_home'] = $r[0]['url'];
 122                                         $_SESSION['visitor_handle'] = $r[0]['addr'];
 123                                         $_SESSION['visitor_visiting'] = $r[0]['uid'];
 124                                         $_SESSION['my_url'] = $r[0]['url'];
 125                                         if (!$quiet) {
 126                                                 info(L10n::t('%1$s welcomes %2$s', $r[0]['username'], $r[0]['name']) . EOL);
 127                                         }
 128
 129                                         // Visitors get 1 day session.
 130                                         $session_id = session_id();
 131                                         $expire = time() + 86400;
 132                                         q("UPDATE `session` SET `expire` = '%s' WHERE `sid` = '%s'",
 133                                                 DBA::escape($expire),
 134                                                 DBA::escape($session_id)
 135                                         );
 136                                 }
 137                         }
 138
 139                         $profile = (count($r) > 0 && isset($r[0]['nickname']) ? $r[0]['nickname'] : '');
 140                         if (!empty($destination_url)) {
 141                                 System::externalRedirect($destination_url);
 142                         } else {
 143                                 $a->internalRedirect('profile/' . $profile);
 144                         }
 145                 }
 146                 $a->internalRedirect();
 147         }
 148
 149         if ($type === 'profile-check' && $dfrn_version < 2.2) {
 150                 if ((strlen($challenge)) && (strlen($sec))) {
 151                         DBA::delete('profile_check', ["`expire` < ?", time()]);
 152                         $r = q("SELECT * FROM `profile_check` WHERE `sec` = '%s' ORDER BY `expire` DESC LIMIT 1",
 153                                 DBA::escape($sec)
 154                         );
 155                         if (!DBA::isResult($r)) {
 156                                 System::xmlExit(3, 'No ticket');
 157                                 // NOTREACHED
 158                         }
 159
 160                         $orig_id = $r[0]['dfrn_id'];
 161                         if (strpos($orig_id, ':')) {
 162                                 $orig_id = substr($orig_id, 2);
 163                         }
 164
 165                         $c = q("SELECT * FROM `contact` WHERE `id` = %d LIMIT 1",
 166                                 intval($r[0]['cid'])
 167                         );
 168                         if (!DBA::isResult($c)) {
 169                                 System::xmlExit(3, 'No profile');
 170                         }
 171
 172                         $contact = $c[0];
 173
 174                         $sent_dfrn_id = hex2bin($dfrn_id);
 175                         $challenge = hex2bin($challenge);
 176
 177                         $final_dfrn_id = '';
 178
 179                         if (($contact['duplex']) && strlen($contact['prvkey'])) {
 180                                 openssl_private_decrypt($sent_dfrn_id, $final_dfrn_id, $contact['prvkey']);
 181                                 openssl_private_decrypt($challenge, $decoded_challenge, $contact['prvkey']);
 182                         } else {
 183                                 openssl_public_decrypt($sent_dfrn_id, $final_dfrn_id, $contact['pubkey']);
 184                                 openssl_public_decrypt($challenge, $decoded_challenge, $contact['pubkey']);
 185                         }
 186
 187                         $final_dfrn_id = substr($final_dfrn_id, 0, strpos($final_dfrn_id, '.'));
 188
 189                         if (strpos($final_dfrn_id, ':') == 1) {
 190                                 $final_dfrn_id = substr($final_dfrn_id, 2);
 191                         }
 192
 193                         if ($final_dfrn_id != $orig_id) {
 194                                 Logger::log('profile_check: ' . $final_dfrn_id . ' != ' . $orig_id, Logger::DEBUG);
 195                                 // did not decode properly - cannot trust this site
 196                                 System::xmlExit(3, 'Bad decryption');
 197                         }
 198
 199                         header("Content-type: text/xml");
 200                         echo "<?xml version=\"1.0\" encoding=\"UTF-8\"?><dfrn_poll><status>0</status><challenge>$decoded_challenge</challenge><sec>$sec</sec></dfrn_poll>";
 201                         exit();
 202                         // NOTREACHED
 203                 } else {
 204                         // old protocol
 205                         switch ($direction) {
 206                                 case 1:
 207                                         $dfrn_id = '0:' . $dfrn_id;
 208                                         break;
 209                                 case 0:
 210                                         $dfrn_id = '1:' . $dfrn_id;
 211                                         break;
 212                                 default:
 213                                         break;
 214                         }
 215
 216                         DBA::delete('profile_check', ["`expire` < ?", time()]);
 217                         $r = q("SELECT * FROM `profile_check` WHERE `dfrn_id` = '%s' ORDER BY `expire` DESC",
 218                                 DBA::escape($dfrn_id));
 219                         if (DBA::isResult($r)) {
 220                                 System::xmlExit(1);
 221                                 return; // NOTREACHED
 222                         }
 223                         System::xmlExit(0);
 224                         return; // NOTREACHED
 225                 }
 226         }
 227 }
 228
 229 function dfrn_poll_post(App $a)
 230 {
 231         $dfrn_id      = defaults($_POST, 'dfrn_id'  , '');
 232         $challenge    = defaults($_POST, 'challenge', '');
 233         $url          = defaults($_POST, 'url'      , '');
 234         $sec          = defaults($_POST, 'sec'      , '');
 235         $ptype        = defaults($_POST, 'type'     , '');
 236         $perm         = defaults($_POST, 'perm'     , 'r');
 237         $dfrn_version = !empty($_POST['dfrn_version']) ? (float) $_POST['dfrn_version'] : 2.0;
 238
 239         if ($ptype === 'profile-check') {
 240                 if (strlen($challenge) && strlen($sec)) {
 241                         Logger::log('dfrn_poll: POST: profile-check');
 242
 243                         DBA::delete('profile_check', ["`expire` < ?", time()]);
 244                         $r = q("SELECT * FROM `profile_check` WHERE `sec` = '%s' ORDER BY `expire` DESC LIMIT 1",
 245                                 DBA::escape($sec)
 246                         );
 247                         if (!DBA::isResult($r)) {
 248                                 System::xmlExit(3, 'No ticket');
 249                                 // NOTREACHED
 250                         }
 251
 252                         $orig_id = $r[0]['dfrn_id'];
 253                         if (strpos($orig_id, ':')) {
 254                                 $orig_id = substr($orig_id, 2);
 255                         }
 256
 257                         $c = q("SELECT * FROM `contact` WHERE `id` = %d LIMIT 1",
 258                                 intval($r[0]['cid'])
 259                         );
 260                         if (!DBA::isResult($c)) {
 261                                 System::xmlExit(3, 'No profile');
 262                         }
 263
 264                         $contact = $c[0];
 265
 266                         $sent_dfrn_id = hex2bin($dfrn_id);
 267                         $challenge = hex2bin($challenge);
 268
 269                         $final_dfrn_id = '';
 270
 271                         if ($contact['duplex'] && strlen($contact['prvkey'])) {
 272                                 openssl_private_decrypt($sent_dfrn_id, $final_dfrn_id, $contact['prvkey']);
 273                                 openssl_private_decrypt($challenge, $decoded_challenge, $contact['prvkey']);
 274                         } else {
 275                                 openssl_public_decrypt($sent_dfrn_id, $final_dfrn_id, $contact['pubkey']);
 276                                 openssl_public_decrypt($challenge, $decoded_challenge, $contact['pubkey']);
 277                         }
 278
 279                         $final_dfrn_id = substr($final_dfrn_id, 0, strpos($final_dfrn_id, '.'));
 280
 281                         if (strpos($final_dfrn_id, ':') == 1) {
 282                                 $final_dfrn_id = substr($final_dfrn_id, 2);
 283                         }
 284
 285                         if ($final_dfrn_id != $orig_id) {
 286                                 Logger::log('profile_check: ' . $final_dfrn_id . ' != ' . $orig_id, Logger::DEBUG);
 287                                 // did not decode properly - cannot trust this site
 288                                 System::xmlExit(3, 'Bad decryption');
 289                         }
 290
 291                         header("Content-type: text/xml");
 292                         echo "<?xml version=\"1.0\" encoding=\"UTF-8\"?><dfrn_poll><status>0</status><challenge>$decoded_challenge</challenge><sec>$sec</sec></dfrn_poll>";
 293                         exit();
 294                         // NOTREACHED
 295                 }
 296         }
 297
 298         $direction = -1;
 299         if (strpos($dfrn_id, ':') == 1) {
 300                 $direction = intval(substr($dfrn_id, 0, 1));
 301                 $dfrn_id = substr($dfrn_id, 2);
 302         }
 303
 304         $r = q("SELECT * FROM `challenge` WHERE `dfrn-id` = '%s' AND `challenge` = '%s' LIMIT 1",
 305                 DBA::escape($dfrn_id),
 306                 DBA::escape($challenge)
 307         );
 308
 309         if (!DBA::isResult($r)) {
 310                 exit();
 311         }
 312
 313         $type = $r[0]['type'];
 314         $last_update = $r[0]['last_update'];
 315
 316         DBA::delete('challenge', ['dfrn-id' => $dfrn_id, 'challenge' => $challenge]);
 317
 318         $sql_extra = '';
 319         switch ($direction) {
 320                 case -1:
 321                         $sql_extra = sprintf(" AND `issued-id` = '%s' ", DBA::escape($dfrn_id));
 322                         $my_id = $dfrn_id;
 323                         break;
 324                 case 0:
 325                         $sql_extra = sprintf(" AND `issued-id` = '%s' AND `duplex` = 1 ", DBA::escape($dfrn_id));
 326                         $my_id = '1:' . $dfrn_id;
 327                         break;
 328                 case 1:
 329                         $sql_extra = sprintf(" AND `dfrn-id` = '%s' AND `duplex` = 1 ", DBA::escape($dfrn_id));
 330                         $my_id = '0:' . $dfrn_id;
 331                         break;
 332                 default:
 333                         $a->internalRedirect();
 334                         break; // NOTREACHED
 335         }
 336
 337         $r = q("SELECT * FROM `contact` WHERE `blocked` = 0 AND `pending` = 0 $sql_extra LIMIT 1");
 338         if (!DBA::isResult($r)) {
 339                 exit();
 340         }
 341
 342         $contact = $r[0];
 343         $owner_uid = $r[0]['uid'];
 344         $contact_id = $r[0]['id'];
 345
 346         if ($type === 'reputation' && strlen($url)) {
 347                 $r = q("SELECT * FROM `contact` WHERE `url` = '%s' AND `uid` = %d LIMIT 1",
 348                         DBA::escape($url),
 349                         intval($owner_uid)
 350                 );
 351                 $reputation = 0;
 352                 $text = '';
 353
 354                 if (DBA::isResult($r)) {
 355                         $reputation = $r[0]['rating'];
 356                         $text = $r[0]['reason'];
 357
 358                         if ($r[0]['id'] == $contact_id) { // inquiring about own reputation not allowed
 359                                 $reputation = 0;
 360                                 $text = '';
 361                         }
 362                 }
 363
 364                 echo "<?xml version=\"1.0\" encoding=\"UTF-8\"?>
 365                 <reputation>
 366                         <url>$url</url>
 367                         <rating>$reputation</rating>
 368                         <description>$text</description>
 369                 </reputation>
 370                 ";
 371                 exit();
 372                 // NOTREACHED
 373         } else {
 374                 // Update the writable flag if it changed
 375                 Logger::log('dfrn_poll: post request feed: ' . print_r($_POST, true), Logger::DATA);
 376                 if ($dfrn_version >= 2.21) {
 377                         if ($perm === 'rw') {
 378                                 $writable = 1;
 379                         } else {
 380                                 $writable = 0;
 381                         }
 382
 383                         if ($writable != $contact['writable']) {
 384                                 q("UPDATE `contact` SET `writable` = %d WHERE `id` = %d",
 385                                         intval($writable),
 386                                         intval($contact_id)
 387                                 );
 388                         }
 389                 }
 390
 391                 header("Content-type: application/atom+xml");
 392                 $o = DFRN::feed($dfrn_id, $a->argv[1], $last_update, $direction);
 393                 echo $o;
 394                 exit();
 395         }
 396 }
 397
 398 function dfrn_poll_content(App $a)
 399 {
 400         $dfrn_id         = defaults($_GET, 'dfrn_id'        , '');
 401         $type            = defaults($_GET, 'type'           , 'data');
 402         $last_update     = defaults($_GET, 'last_update'    , '');
 403         $destination_url = defaults($_GET, 'destination_url', '');
 404         $sec             = defaults($_GET, 'sec'            , '');
 405         $dfrn_version    = !empty($_GET['dfrn_version'])    ? (float) $_GET['dfrn_version'] : 2.0;
 406         $quiet           = !empty($_GET['quiet']);
 407
 408         $direction = -1;
 409         if (strpos($dfrn_id, ':') == 1) {
 410                 $direction = intval(substr($dfrn_id, 0, 1));
 411                 $dfrn_id = substr($dfrn_id, 2);
 412         }
 413
 414         if ($dfrn_id != '') {
 415                 // initial communication from external contact
 416                 $hash = Strings::getRandomHex();
 417
 418                 $status = 0;
 419
 420                 DBA::delete('challenge', ["`expire` < ?", time()]);
 421
 422                 if ($type !== 'profile') {
 423                         $r = q("INSERT INTO `challenge` ( `challenge`, `dfrn-id`, `expire` , `type`, `last_update` )
 424                                 VALUES( '%s', '%s', '%s', '%s', '%s' ) ",
 425                                 DBA::escape($hash),
 426                                 DBA::escape($dfrn_id),
 427                                 intval(time() + 60 ),
 428                                 DBA::escape($type),
 429                                 DBA::escape($last_update)
 430                         );
 431                 }
 432
 433                 $sql_extra = '';
 434                 switch ($direction) {
 435                         case -1:
 436                                 if ($type === 'profile') {
 437                                         $sql_extra = sprintf(" AND (`dfrn-id` = '%s' OR `issued-id` = '%s') ", DBA::escape($dfrn_id), DBA::escape($dfrn_id));
 438                                 } else {
 439                                         $sql_extra = sprintf(" AND `issued-id` = '%s' ", DBA::escape($dfrn_id));
 440                                 }
 441
 442                                 $my_id = $dfrn_id;
 443                                 break;
 444                         case 0:
 445                                 $sql_extra = sprintf(" AND `issued-id` = '%s' AND `duplex` = 1 ", DBA::escape($dfrn_id));
 446                                 $my_id = '1:' . $dfrn_id;
 447                                 break;
 448                         case 1:
 449                                 $sql_extra = sprintf(" AND `dfrn-id` = '%s' AND `duplex` = 1 ", DBA::escape($dfrn_id));
 450                                 $my_id = '0:' . $dfrn_id;
 451                                 break;
 452                         default:
 453                                 $a->internalRedirect();
 454                                 break; // NOTREACHED
 455                 }
 456
 457                 $nickname = $a->argv[1];
 458
 459                 $r = q("SELECT `contact`.*, `user`.`username`, `user`.`nickname`
 460                         FROM `contact` LEFT JOIN `user` ON `contact`.`uid` = `user`.`uid`
 461                         WHERE `contact`.`blocked` = 0 AND `contact`.`pending` = 0
 462                         AND `user`.`nickname` = '%s' $sql_extra LIMIT 1",
 463                         DBA::escape($nickname)
 464                 );
 465                 if (DBA::isResult($r)) {
 466                         $challenge = '';
 467                         $encrypted_id = '';
 468                         $id_str = $my_id . '.' . mt_rand(1000, 9999);
 469
 470                         if (($r[0]['duplex'] && strlen($r[0]['pubkey'])) || !strlen($r[0]['prvkey'])) {
 471                                 openssl_public_encrypt($hash, $challenge, $r[0]['pubkey']);
 472                                 openssl_public_encrypt($id_str, $encrypted_id, $r[0]['pubkey']);
 473                         } else {
 474                                 openssl_private_encrypt($hash, $challenge, $r[0]['prvkey']);
 475                                 openssl_private_encrypt($id_str, $encrypted_id, $r[0]['prvkey']);
 476                         }
 477
 478                         $challenge = bin2hex($challenge);
 479                         $encrypted_id = bin2hex($encrypted_id);
 480                 } else {
 481                         $status = 1;
 482                         $challenge = '';
 483                         $encrypted_id = '';
 484                 }
 485
 486                 if (($type === 'profile') && (strlen($sec))) {
 487                         // heluecht: I don't know why we don't fail immediately when the user or contact hadn't been found.
 488                         // Since it doesn't make sense to continue from this point on, we now fail here. This should be safe.
 489                         if (!DBA::isResult($r)) {
 490                                 System::httpExit(404, ["title" => L10n::t('Page not found.')]);
 491                         }
 492
 493                         // URL reply
 494                         if ($dfrn_version < 2.2) {
 495                                 $s = Network::fetchUrl($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                                 );
 502                         } else {
 503                                 $s = Network::post($r[0]['poll'], [
 504                                         'dfrn_id' => $encrypted_id,
 505                                         'type' => 'profile-check',
 506                                         'dfrn_version' => DFRN_PROTOCOL_VERSION,
 507                                         'challenge' => $challenge,
 508                                         'sec' => $sec
 509                                 ])->getBody();
 510                         }
 511
 512                         Logger::log("dfrn_poll: sec profile: " . $s, Logger::DATA);
 513
 514                         if (strlen($s) && strstr($s, '<?xml')) {
 515                                 $xml = XML::parseString($s);
 516
 517                                 Logger::log('dfrn_poll: profile: parsed xml: ' . print_r($xml, true), Logger::DATA);
 518
 519                                 Logger::log('dfrn_poll: secure profile: challenge: ' . $xml->challenge . ' expecting ' . $hash);
 520                                 Logger::log('dfrn_poll: secure profile: sec: ' . $xml->sec . ' expecting ' . $sec);
 521
 522                                 if (((int) $xml->status == 0) && ($xml->challenge == $hash) && ($xml->sec == $sec)) {
 523                                         $_SESSION['authenticated'] = 1;
 524                                         if (empty($_SESSION['remote'])) {
 525                                                 $_SESSION['remote'] = [];
 526                                         }
 527
 528                                         $_SESSION['remote'][] = ['cid' => $r[0]['id'], 'uid' => $r[0]['uid'], 'url' => $r[0]['url']];
 529                                         $_SESSION['visitor_id'] = $r[0]['id'];
 530                                         $_SESSION['visitor_home'] = $r[0]['url'];
 531                                         $_SESSION['visitor_visiting'] = $r[0]['uid'];
 532                                         $_SESSION['my_url'] = $r[0]['url'];
 533                                         if (!$quiet) {
 534                                                 info(L10n::t('%1$s welcomes %2$s', $r[0]['username'], $r[0]['name']) . EOL);
 535                                         }
 536
 537                                         // Visitors get 1 day session.
 538                                         $session_id = session_id();
 539                                         $expire = time() + 86400;
 540                                         q("UPDATE `session` SET `expire` = '%s' WHERE `sid` = '%s'",
 541                                                 DBA::escape($expire),
 542                                                 DBA::escape($session_id)
 543                                         );
 544                                 }
 545                         }
 546
 547                         $profile = ((DBA::isResult($r) && $r[0]['nickname']) ? $r[0]['nickname'] : $nickname);
 548
 549                         switch ($destination_url) {
 550                                 case 'profile':
 551                                         $a->internalRedirect('profile/' . $profile . '?f=&tab=profile');
 552                                         break;
 553                                 case 'photos':
 554                                         $a->internalRedirect('photos/' . $profile);
 555                                         break;
 556                                 case 'status':
 557                                 case '':
 558                                         $a->internalRedirect('profile/' . $profile);
 559                                         break;
 560                                 default:
 561                                         $appendix = (strstr($destination_url, '?') ? '&f=&redir=1' : '?f=&redir=1');
 562                                         $a->redirect($destination_url . $appendix);
 563                                         break;
 564                         }
 565                         // NOTREACHED
 566                 } else {
 567                         // XML reply
 568                         header("Content-type: text/xml");
 569                         echo '<?xml version="1.0" encoding="UTF-8"?>' . "\r\n"
 570                                 . '<dfrn_poll>' . "\r\n"
 571                                 . "\t" . '<status>' . $status . '</status>' . "\r\n"
 572                                 . "\t" . '<dfrn_version>' . DFRN_PROTOCOL_VERSION . '</dfrn_version>' . "\r\n"
 573                                 . "\t" . '<dfrn_id>' . $encrypted_id . '</dfrn_id>' . "\r\n"
 574                                 . "\t" . '<challenge>' . $challenge . '</challenge>' . "\r\n"
 575                                 . '</dfrn_poll>' . "\r\n";
 576                         exit();
 577                         // NOTREACHED
 578                 }
 579         }
 580 }