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