src/org/ibex/mail/SMTP.java

   1 // Copyright 2000-2005 the Contributors, as shown in the revision logs.
   2 // Licensed under the Apache Public Source License 2.0 ("the License").
   3 // You may not use this file except in compliance with the License.
   4
   5 package org.ibex.mail;
   6 import org.ibex.mail.target.*;
   7 import org.ibex.util.*;
   8 import org.ibex.net.*;
   9 import org.ibex.io.*;
  10 import java.net.*;
  11 import java.io.*;
  12 import java.util.*;
  13 import java.text.*;
  14 import javax.naming.*;
  15 import javax.naming.directory.*;
  16
  17 // FIXME: inbound throttling/ratelimiting
  18
  19 // RFC's implemented
  20 // RFC2554: SMTP Service Extension for Authentication
  21 //     - did not implement section 5, though
  22 // RFC4616: SASL PLAIN
  23
  24 // Note: we can't actually use status codes for feedback if we accept
  25 // multiple destination addresses...  a failure on one and success on
  26 // the other...
  27
  28 // FIXME: logging: current logging sucks
  29 // FIXME: loop prevention
  30 // FIXME: probably need some throttling on outbound mail
  31
  32 // FEATURE: public static boolean validate(Address a)
  33 // FEATURE: rate-limiting
  34
  35 // FEATURE: infer messageid, date, if not present (?)
  36 // FEATURE: exponential backoff on retry time?
  37 // FEATURE: RFC2822, section 4.5.1: special "postmaster" address
  38 // FEATURE: RFC2822, section 4.5.4.1: retry strategies
  39 // FEATURE: RFC2822, section 5, multiple MX records, preferences, ordering
  40 // FEATURE: RFC2822, end of 4.1.2: backslashes in headers
  41 public class SMTP {
  42
  43     public static final SimpleDateFormat dateFormat = new SimpleDateFormat("EEE, d MMM yyyy HH:mm:ss Z");
  44     public static final int numOutgoingThreads = 5;
  45
  46     public static final int GRAYLIST_MINWAIT =  1000 * 60 * 60;           // one hour
  47     public static final int GRAYLIST_MAXWAIT =  1000 * 60 * 60 * 24 * 5;  // five days
  48
  49     public static final Graylist graylist;
  50     public static final Whitelist whitelist;
  51     static {
  52         try {
  53             graylist =  new Graylist(Mailbox.STORAGE_ROOT+"/db/graylist.sqlite");
  54             whitelist = new Whitelist(Mailbox.STORAGE_ROOT+"/db/whitelist.sqlite");
  55         } catch (Exception e) {
  56             throw new RuntimeException(e);
  57         }
  58     }
  59
  60     public static final int MAX_MESSAGE_SIZE =
  61         Integer.parseInt(System.getProperty("org.ibex.mail.smtp.maxMessageSize", "-1"));
  62
  63     private static final Mailbox spool =
  64         FileBasedMailbox.getFileBasedMailbox(Mailbox.STORAGE_ROOT,false).slash("spool",true).slash("smtp",true).getMailbox();
  65
  66     static {
  67         for(int i=0; i<numOutgoingThreads; i++)
  68             new Outgoing().start();
  69     }
  70
  71     public static void enqueue(Message m) throws IOException {
  72         if (!m.envelopeTo.isLocal()) Outgoing.enqueue(m);
  73         else                         Target.root.accept(m);
  74     }
  75
  76     public static class SMTPException extends MailException {
  77         int code;
  78         String message;
  79         public SMTPException(String s) {
  80             try {
  81                 code = Integer.parseInt(s.substring(0, s.indexOf(' ')));
  82                 message = s.substring(s.indexOf(' ')+1);
  83             } catch (NumberFormatException nfe) {
  84                 code = -1;
  85                 message = s;
  86             }
  87         }
  88         public String toString() { return "SMTP " + code + ": " + message; }
  89         public String getMessage() { return toString(); }
  90     }
  91
  92     // Server //////////////////////////////////////////////////////////////////////////////
  93
  94     public static class Server {
  95         public void handleRequest(Connection conn) throws IOException {
  96             conn.setTimeout(5 * 60 * 1000);
  97             conn.setNewline("\r\n");
  98             conn.println("220 " + conn.vhost + " ESMTP " + this.getClass().getName());
  99             Address from = null;
 100             Vector to = new Vector();
 101             boolean ehlo = false;
 102             String remotehost = null;
 103             String authenticatedAs = null;
 104             int failedRcptCount = 0;
 105             for(String command = conn.readln(); ; command = conn.readln()) try {
 106                 if (command == null) return;
 107                 Log.warn("**"+conn.getRemoteAddress()+"**", command);
 108                 String c = command.toUpperCase();
 109                 if (c.startsWith("HELO"))        {
 110                     remotehost = c.substring(5).trim();
 111                     conn.println("250 HELO " + conn.vhost);
 112                     from = null; to = new Vector();
 113                 } else if (c.startsWith("EHLO")) {
 114                     remotehost = c.substring(5).trim();
 115                     conn.println("250-"+conn.vhost);
 116                     //conn.println("250-AUTH");
 117                     conn.println("250-AUTH PLAIN");
 118                     //conn.println("250-STARTTLS");
 119                     conn.println("250 HELP");
 120                     ehlo = true;
 121                     from = null; to = new Vector();
 122                 } else if (c.startsWith("RSET")) { conn.println("250 reset ok");           from = null; to = new Vector();
 123                 } else if (c.startsWith("HELP")) { conn.println("214 you are beyond help.  see a trained professional.");
 124                 } else if (c.startsWith("VRFY")) { conn.println("502 VRFY not supported");
 125                 } else if (c.startsWith("EXPN")) { conn.println("502 EXPN not supported");
 126                 } else if (c.startsWith("NOOP")) { conn.println("250 OK");
 127                 } else if (c.startsWith("QUIT")) { conn.println("221 " + conn.vhost + " closing connection"); return;
 128                 } else if (c.startsWith("STARTTLS")) {
 129                     conn.println("220 starting TLS...");
 130                     conn.flush();
 131                     conn = conn.negotiateSSL(true);
 132                     from = null; to = new Vector();
 133                 } else if (c.startsWith("AUTH")) {
 134                     if (authenticatedAs != null) {
 135                         conn.println("503 you are already authenticated; you must reconnect to reauth");
 136                     } else {
 137                         String mechanism = command.substring(4).trim();
 138                         String rest = "";
 139                         if (mechanism.indexOf(' ')!=-1) {
 140                             rest      = mechanism.substring(mechanism.indexOf(' ')+1).trim();
 141                             mechanism = mechanism.substring(0, mechanism.indexOf(' '));
 142                         }
 143                         if (mechanism.equals("PLAIN")) {
 144                             // 538 Encryption required for requested authentication mechanism?
 145                             byte[] bytes = Encode.fromBase64(rest);
 146                             String authenticateUser = null;
 147                             String authorizeUser = null;
 148                             String password = null;
 149                             int start = 0;
 150                             for(int i=0; i<=bytes.length; i++) {
 151                                 if (i<bytes.length && bytes[i]!=0) continue;
 152                                 String result = new String(bytes, start, i-start, "UTF-8");
 153                                 if (authenticateUser==null)   authenticateUser = result;
 154                                 else if (authorizeUser==null) authorizeUser = result;
 155                                 else if (password==null)      password = result;
 156                                 start = i+1;
 157                             }
 158                             // FIXME: be smarter here
 159                             if (Main.auth.login(authorizeUser, password)!=null)
 160                                 authenticatedAs = authenticateUser;
 161                             conn.println("235 Authentication successful");
 162                             /*
 163                         } else if (mechanism.equals("CRAM-MD5")) {
 164                             String challenge = ;
 165                             conn.println("334 "+challenge);
 166                             String resp = conn.readln();
 167                             if (resp.equals("*")) {
 168                                 conn.println("501 client requested AUTH cancellation");
 169                             }
 170                         } else if (mechanism.equals("ANONYMOUS")) {
 171                         } else if (mechanism.equals("EXTERNAL")) {
 172                         } else if (mechanism.equals("DIGEST-MD5")) {
 173                             */
 174                         } else {
 175                             conn.println("504 unrecognized authentication type");
 176                         }
 177                         // on success, reset to initial state; client will EHLO again
 178                         from = null; to = new Vector();
 179                     }
 180                 } else if (c.startsWith("MAIL FROM:")) {
 181                     command = command.substring(10).trim();
 182                     from = command.equals("<>") ? null : new Address(command);
 183                     conn.println("250 " + from + " is syntactically correct");
 184                     // FEATURE: perform SMTP validation on the address, reject if invalid
 185                 } else if (c.startsWith("RCPT TO:")) {
 186                     // some clients are broken and put RCPT first; we will tolerate this
 187                     command = command.substring(8).trim();
 188                     if(command.indexOf(' ') != -1) command = command.substring(0, command.indexOf(' '));
 189                     Address addr = new Address(command);
 190                     if (conn.getRemoteAddress().isLoopbackAddress() || (from!=null&&from.toString().indexOf("johnw")!=-1)) {
 191                         conn.println("250 you are connected locally, so I will let you send");
 192                         to.addElement(addr);
 193                         if (!whitelist.isWhitelisted(addr))
 194                             whitelist.addWhitelist(addr);
 195                     } else if (authenticatedAs!=null) {
 196                         conn.println("250 you are authenticated as "+authenticatedAs+", so I will let you send");
 197                         to.addElement(addr);
 198                         if (!whitelist.isWhitelisted(addr))
 199                             whitelist.addWhitelist(addr);
 200                     } else if (addr.isLocal()) {
 201                         if (to.size() > 3) {
 202                             conn.println("536 sorry, limit on 3 RCPT TO's per DATA");
 203                         } else {
 204                             // FEATURE: should check the address further and give 550 if undeliverable
 205                             conn.println("250 " + addr + " is on this machine; I will deliver it");
 206                             to.addElement(addr);
 207                         }
 208                     } else {
 209                         conn.println("535 sorry, " + addr + " is not on this machine, you are not connected from localhost, and I will not relay without SMTP AUTH");
 210                         Log.warn("","535 sorry, " + addr + " is not on this machine, you are not connected from localhost, and I will not relay without SMTP AUTH");
 211                         failedRcptCount++;
 212                         if (failedRcptCount > 3) {
 213                             conn.close();
 214                             return;
 215                         }
 216                     }
 217                     conn.flush();
 218                 } else if (c.startsWith("DATA")) {
 219                     //if (from == null) { conn.println("503 MAIL FROM command must precede DATA"); continue; }
 220                     if (to == null || to.size()==0) { conn.println("503 RCPT TO command must precede DATA"); continue; }
 221                     if (!graylist.isWhitelisted(conn.getRemoteAddress()) && !conn.getRemoteAddress().isLoopbackAddress() && authenticatedAs==null) {
 222                         long when = graylist.getGrayListTimestamp(conn.getRemoteAddress(), from+"", to+"");
 223                         if (when == 0 || System.currentTimeMillis() - when > GRAYLIST_MAXWAIT) {
 224                             graylist.setGrayListTimestamp(conn.getRemoteAddress(), from+"", to+"",  System.currentTimeMillis());
 225                             conn.println("451 you are graylisted; please try back in one hour to be whitelisted");
 226                             Log.warn(conn.getRemoteAddress().toString(), "451 you are graylisted; please try back in one hour to be whitelisted");
 227                             conn.flush();
 228                             continue;
 229                         } else if (System.currentTimeMillis() - when > GRAYLIST_MINWAIT) {
 230                             graylist.addWhitelist(conn.getRemoteAddress());
 231                             conn.println("354 (you have been whitelisted) Enter message, ending with \".\" on a line by itself");
 232                             Log.warn(conn.getRemoteAddress().toString(), "has been whitelisted");
 233                         } else {
 234                             conn.println("451 you are still graylisted (since "+new java.util.Date(when)+")");
 235                             conn.flush();
 236                             Log.warn(conn.getRemoteAddress().toString(), "451 you are still graylisted (since "+new java.util.Date(when)+")");
 237                             continue;
 238                         }
 239                     } else {
 240                         conn.println("354 Enter message, ending with \".\" on a line by itself");
 241                     }
 242                     conn.flush();
 243                     try {
 244                         // FIXME: deal with messages larger than memory here?
 245                         StringBuffer buf = new StringBuffer();
 246                         buf.append("Received: from " + conn.getRemoteHostname() + " (" + remotehost + ")\r\n");
 247                         buf.append("          by "+conn.vhost+" ("+SMTP.class.getName()+") with "+(ehlo?"ESMTP":"SMTP") + "\r\n");
 248                         buf.append("          for ");
 249                         // FIXME: this is leaking BCC addrs
 250                         // for(int i=0; i<to.size(); i++) buf.append(to.elementAt(i) + " ");
 251                         buf.append("; " + dateFormat.format(new Date()) + "\r\n");
 252
 253                         // FIXME: some sort of stream transformer here?
 254                         while(true) {
 255                             String s = conn.readln();
 256                             if (s == null) throw new RuntimeException("connection closed");
 257                             if (s.equals(".")) break;
 258                             if (s.startsWith(".")) s = s.substring(1);
 259                             buf.append(s + "\r\n");
 260                             if (MAX_MESSAGE_SIZE != -1 && buf.length() > MAX_MESSAGE_SIZE && (from+"").indexOf("paperless")==-1) {
 261                                 Log.error("**"+conn.getRemoteAddress()+"**",
 262                                           "sorry, this mail server only accepts messages of less than " +
 263                                           ByteSize.toString(MAX_MESSAGE_SIZE));
 264                                 throw new MailException.Malformed("sorry, this mail server only accepts messages of less than " +
 265                                                                   ByteSize.toString(MAX_MESSAGE_SIZE));
 266                             }
 267                         }
 268                         String message = buf.toString();
 269                         Message m = null;
 270                         for(int i=0; i<to.size(); i++)
 271                             enqueue(m = Message.newMessage(Fountain.Util.create(message)).withEnvelope(from, (Address)to.elementAt(i)));
 272                         if (m != null) Log.info(SMTP.class, "accepted message: " + m.summary());
 273                         conn.println("250 message accepted");
 274                         conn.flush();
 275                         from = null; to = new Vector();
 276                     } catch (MailException.Malformed mfe) {    conn.println("501 " + mfe.toString());
 277                     } catch (MailException.MailboxFull mbf) {  conn.println("452 " + mbf);
 278                     } catch (Script.Later.LaterException le) { conn.println("453 try again later");
 279                     } catch (Script.Reject.RejectException re) {
 280                         Log.warn(SMTP.class, "rejecting message due to: " + re.reason + "\n   " + re.m.summary());
 281                         conn.println("501 " + re.reason);
 282                     }
 283                 } else                    { conn.println("500 unrecognized command"); }
 284             } catch (Message.Malformed e) { conn.println("501 " + e.toString()); }
 285         }
 286     }
 287
 288
 289     // Outgoing Mail Thread //////////////////////////////////////////////////////////////////////////////
 290
 291     public static class Outgoing extends Thread {
 292
 293         private static final HashMap deadHosts = new HashMap();
 294         public static void enqueue(Message m) throws IOException {
 295             if (m == null) { Log.warn(Outgoing.class, "attempted to enqueue(null)"); return; }
 296             String traces = m.headers.get("Received");
 297             if (traces!=null) {
 298                 int lines = 0;
 299                 for(int i=0; i<traces.length(); i++)
 300                     if (traces.charAt(i)=='\n' || traces.charAt(i)=='\r')
 301                         lines++;
 302                 if (lines > 100) { // required by rfc
 303                     Log.warn(SMTP.Outgoing.class, "Message with " + lines + " trace hops; dropping\n" + m.summary());
 304                     return;
 305                 }
 306             }
 307             synchronized(Outgoing.class) {
 308                 spool.insert(m, Mailbox.Flag.defaultFlags);
 309                 Outgoing.class.notifyAll();
 310             }
 311         }
 312
 313         public static boolean attempt(Message m) throws IOException { return attempt(m, false); }
 314         public static boolean attempt(Message m, boolean noBounces) throws IOException {
 315             if (m.envelopeTo == null) {
 316                 Log.warn(SMTP.Outgoing.class, "aieeee, null envelopeTo: " + m.summary());
 317                 return false;
 318             }
 319             InetAddress[] mx = getMailExchangerIPs(m.envelopeTo.host);
 320             if (mx.length == 0) {
 321                 if (!noBounces) {
 322                     enqueue(m.bounce("could not resolve " + m.envelopeTo.host));
 323                     return true;
 324                 } else {
 325                     Log.warn(SMTP.Outgoing.class, "could not resolve " + m.envelopeTo.host);
 326                     return false;
 327                 }
 328             }
 329             if (new Date().getTime() - m.arrival.getTime() > 1000 * 60 * 60 * 24 * 5) {
 330                 if (!noBounces) {
 331                     enqueue(m.bounce("could not send for 5 days"));
 332                     return true;
 333                 } else {
 334                     Log.warn(SMTP.Outgoing.class, "could not send for 5 days: " + m.summary());
 335                     return false;
 336                 }
 337             }
 338             for(int i=0; i<mx.length; i++) {
 339                 //if (deadHosts.contains(mx[i])) continue;
 340                 if (attempt(m, mx[i])) return true;
 341             }
 342             return false;
 343         }
 344
 345         private static void check(String s, Connection conn) {
 346             if (s==null) return;
 347             while (s.length() > 3 && s.charAt(3) == '-') s = conn.readln();
 348             //if (s.startsWith("4")||s.startsWith("5")) throw new SMTPException(s);
 349             if (!s.startsWith("2")&&!s.startsWith("3")) throw new SMTPException(s);
 350         }
 351         private static boolean attempt(final Message m, final InetAddress mx) {
 352             boolean accepted = false;
 353             Connection conn = null;
 354             try {
 355                 conn = new Connection(new Socket(mx, 25), InetAddress.getLocalHost().getHostName());
 356                 conn.setNewline("\r\n");
 357                 conn.setTimeout(60 * 1000);
 358                 check(conn.readln(), conn);  // banner
 359                 try {
 360                     conn.println("EHLO " + conn.vhost);
 361                     check(conn.readln(), conn);
 362                 } catch (SMTPException smtpe) {
 363                     conn.println("HELO " + conn.vhost);
 364                     check(conn.readln(), conn);
 365                 }
 366                 String envelopeFrom = m.envelopeFrom==null ? "" : m.envelopeFrom.toString();
 367                 conn.println("MAIL FROM:<" + envelopeFrom +">");            check(conn.readln(), conn);
 368                 conn.println("RCPT TO:<"   + m.envelopeTo.toString()+">");  check(conn.readln(), conn);
 369                 conn.println("DATA");                                       check(conn.readln(), conn);
 370
 371                 Headers head = new Headers(m.headers,
 372                                            new String[] {
 373                                                "return-path", null,
 374                                                "bcc", null
 375                                            });
 376                 Stream stream = head.getStream();
 377                 for(String s = stream.readln(); s!=null; s=stream.readln()) {
 378                     if (s.startsWith(".")) conn.print(".");
 379                     conn.println(s);
 380                 }
 381                 conn.println("");
 382                 stream = m.getBody().getStream();
 383                 for(String s = stream.readln(); s!=null; s=stream.readln()) {
 384                     if (s.startsWith(".")) conn.print(".");
 385                     conn.println(s);
 386                 }
 387                 conn.println(".");
 388                 String resp = conn.readln();
 389                 if (resp == null)
 390                     throw new SMTPException("server " + mx + " closed connection without accepting message");
 391                 check(resp, conn);
 392                 Log.warn(SMTP.Outgoing.class, "success: " + mx + " accepted " + m.summary() + "\n["+resp+"]");
 393                 accepted = true;
 394                 conn.close();
 395             } catch (SMTPException e) {
 396                 if (accepted) return true;
 397                 Log.warn(SMTP.Outgoing.class, "    unable to send; error=" + e);
 398                 Log.warn(SMTP.Outgoing.class, "      message: " + m.summary());
 399                 Log.warn(SMTP.Outgoing.class, e);
 400                 /*
 401                   // FIXME: we should not be bouncing here!
 402                 if (e.code >= 500 && e.code <= 599) {
 403                     try {
 404                         attempt(m.bounce("unable to deliver: " + e), true);
 405                     } catch (Exception ex) {
 406                         Log.error(SMTP.Outgoing.class, "exception while trying to deliver bounce; giving up completely");
 407                         Log.error(SMTP.Outgoing.class, ex);
 408                     }
 409                     return true;
 410                 }
 411                 */
 412                 return false;
 413             } catch (Exception e) {
 414                 if (accepted) return true;
 415                 Log.warn(SMTP.Outgoing.class, "    unable to send; error=" + e);
 416                 Log.warn(SMTP.Outgoing.class, "      message: " + m.summary());
 417                 Log.warn(SMTP.Outgoing.class, e);
 418                 //if (conn != null) Log.warn(SMTP.Outgoing.class, conn.dumpLog());
 419                 return false;
 420             } finally {
 421                 if (conn != null) conn.close();
 422             }
 423             return accepted;
 424         }
 425
 426         private static HashSet<Outgoing> threads = new HashSet<Outgoing>();
 427         private static int serials = 1;
 428         private int serial = serials++;
 429         private Mailbox.Iterator it;
 430
 431         public Outgoing() {
 432             synchronized(Outgoing.class) {
 433                 threads.add(this);
 434             }
 435         }
 436
 437         public void wake() {
 438             int count = spool.count(Query.all());
 439             Log.info(SMTP.Outgoing.class, "outgoing thread #"+serial+" woke up; " + count + " messages to send");
 440             try {
 441                 while(true) {
 442                     boolean good = false;
 443                     synchronized(Outgoing.class) {
 444                         it = spool.iterator();
 445                         OUTER: for(; it.next(); ) {
 446                             for(Outgoing o : threads)
 447                                 if (o!=this && o.it != null && o.it.uid()==it.uid())
 448                                     continue OUTER;
 449                             good = true;
 450                             break;
 451                         }
 452                     }
 453                     if (!good) break;
 454                     try {
 455                         if (attempt(it.cur())) it.delete();
 456                     } catch (Exception e) {
 457                         Log.error(SMTP.Outgoing.class, e);
 458                     }
 459                     Log.info(this, "sleeping for 3s...");
 460                     Thread.sleep(3000);
 461                 }
 462             } catch (Exception e) {
 463                 //if (e instanceof InterruptedException) throw e;
 464                 Log.error(SMTP.Outgoing.class, e);
 465             }
 466             Log.info(SMTP.Outgoing.class, "outgoing thread #"+serial+" going back to sleep");
 467             it = null;
 468         }
 469
 470         public void run() {
 471             try {
 472                 while(true) {
 473                     Log.setThreadAnnotation("[outgoing #"+serial+"] ");
 474                     wake();
 475                     Thread.sleep(1000);
 476                     synchronized(Outgoing.class) {
 477                         Outgoing.class.wait(5 * 60 * 1000);
 478                     }
 479                 }
 480             } catch (InterruptedException e) { Log.warn(this, e); }
 481         }
 482     }
 483
 484     public static InetAddress[] getMailExchangerIPs(String hostName) {
 485         InetAddress[] ret;
 486         try {
 487             Hashtable env = new Hashtable();
 488             env.put("java.naming.factory.initial", "com.sun.jndi.dns.DnsContextFactory");
 489             DirContext ictx = new InitialDirContext(env);
 490             Attributes attrs = ictx.getAttributes(hostName, new String[] { "MX" });
 491             Attribute attr = attrs.get("MX");
 492             if (attr == null) {
 493                 ret = new InetAddress[1];
 494                 try {
 495                     ret[0] = InetAddress.getByName(hostName);
 496                     if (ret[0].equals(IP.getIP(127,0,0,1)) || ret[0].isLoopbackAddress()) throw new UnknownHostException();
 497                     return ret;
 498                 } catch (UnknownHostException uhe) {
 499                     Log.warn(SMTP.class, "no MX hosts or A record for " + hostName);
 500                     return new InetAddress[0];
 501                 }
 502             } else {
 503                 ret = new InetAddress[attr.size()];
 504                 NamingEnumeration ne = attr.getAll();
 505                 for(int i=0; ne.hasMore();) {
 506                     String mx = (String)ne.next();
 507                     // FIXME we should be sorting here
 508                     mx = mx.substring(mx.indexOf(" ") + 1);
 509                     if (mx.charAt(mx.length() - 1) == '.') mx = mx.substring(0, mx.length() - 1);
 510                     InetAddress ia = InetAddress.getByName(mx);
 511                     if (ia.equals(IP.getIP(127,0,0,1)) || ia.isLoopbackAddress()) continue;
 512                     ret[i++] = ia;
 513                 }
 514             }
 515         } catch (Exception e) {
 516             Log.warn(SMTP.class, "couldn't find MX host for " + hostName + " due to");
 517             Log.warn(SMTP.class, e);
 518             return new InetAddress[0];
 519         }
 520         return ret;
 521     }
 522 }