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                     } else {
 189                         conn.println("535 sorry, " + addr + " is not on this machine, you are not connected from localhost, and I will not relay without SMTP AUTH");
 190                         Log.warn("","535 sorry, " + addr + " is not on this machine, you are not connected from localhost, and I will not relay without SMTP AUTH");
 191                     }
 192                     conn.flush();
 193                 } else if (c.startsWith("DATA")) {
 194                     //if (from == null) { conn.println("503 MAIL FROM command must precede DATA"); continue; }
 195                     if (to == null || to.size()==0) { conn.println("503 RCPT TO command must precede DATA"); continue; }
 196                     if (!graylist.isWhitelisted(conn.getRemoteAddress()) && !conn.getRemoteAddress().isLoopbackAddress() && authenticatedAs==null) {
 197                         long when = graylist.getGrayListTimestamp(conn.getRemoteAddress(), from+"", to+"");
 198                         if (when == 0 || System.currentTimeMillis() - when > GRAYLIST_MAXWAIT) {
 199                             graylist.setGrayListTimestamp(conn.getRemoteAddress(), from+"", to+"",  System.currentTimeMillis());
 200                             conn.println("451 you are graylisted; please try back in one hour to be whitelisted");
 201                             Log.warn(conn.getRemoteAddress().toString(), "451 you are graylisted; please try back in one hour to be whitelisted");
 202                             conn.flush();
 203                             continue;
 204                         } else if (System.currentTimeMillis() - when > GRAYLIST_MINWAIT) {
 205                             graylist.addWhitelist(conn.getRemoteAddress());
 206                             conn.println("354 (you have been whitelisted) Enter message, ending with \".\" on a line by itself");
 207                             Log.warn(conn.getRemoteAddress().toString(), "has been whitelisted");
 208                         } else {
 209                             conn.println("451 you are still graylisted (since "+new java.util.Date(when)+")");
 210                             conn.flush();
 211                             Log.warn(conn.getRemoteAddress().toString(), "451 you are still graylisted (since "+new java.util.Date(when)+")");
 212                             continue;
 213                         }
 214                     } else {
 215                         conn.println("354 Enter message, ending with \".\" on a line by itself");
 216                     }
 217                     conn.flush();
 218                     try {
 219                         // FIXME: deal with messages larger than memory here?
 220                         StringBuffer buf = new StringBuffer();
 221                         buf.append("Received: from " + conn.getRemoteHostname() + " (" + remotehost + ")\r\n");
 222                         buf.append("          by "+conn.vhost+" ("+SMTP.class.getName()+") with "+(ehlo?"ESMTP":"SMTP") + "\r\n");
 223                         buf.append("          for ");
 224                         // FIXME: this is leaking BCC addrs
 225                         // for(int i=0; i<to.size(); i++) buf.append(to.elementAt(i) + " ");
 226                         buf.append("; " + dateFormat.format(new Date()) + "\r\n");
 227
 228                         // FIXME: some sort of stream transformer here?
 229                         while(true) {
 230                             String s = conn.readln();
 231                             if (s == null) throw new RuntimeException("connection closed");
 232                             if (s.equals(".")) break;
 233                             if (s.startsWith(".")) s = s.substring(1);
 234                             buf.append(s + "\r\n");
 235                             if (MAX_MESSAGE_SIZE != -1 && buf.length() > MAX_MESSAGE_SIZE) {
 236                                 Log.error("**"+conn.getRemoteAddress()+"**",
 237                                           "sorry, this mail server only accepts messages of less than " +
 238                                           ByteSize.toString(MAX_MESSAGE_SIZE));
 239                                 throw new MailException.Malformed("sorry, this mail server only accepts messages of less than " +
 240                                                                   ByteSize.toString(MAX_MESSAGE_SIZE));
 241                             }
 242                         }
 243                         String body = buf.toString();
 244                         Message m = null;
 245                         for(int i=0; i<to.size(); i++) {
 246                             m = Message.newMessage(Fountain.Util.create(body), from, (Address)to.elementAt(i));
 247                             enqueue(m);
 248                         }
 249                         if (m != null) Log.info(SMTP.class, "accepted message: " + m.summary());
 250                         conn.println("250 message accepted");
 251                         conn.flush();
 252                         from = null; to = new Vector();
 253                     } catch (MailException.Malformed mfe) {    conn.println("501 " + mfe.toString());
 254                     } catch (MailException.MailboxFull mbf) {  conn.println("452 " + mbf);
 255                     } catch (Script.Later.LaterException le) { conn.println("453 try again later");
 256                     } catch (Script.Reject.RejectException re) {
 257                         Log.warn(SMTP.class, "rejecting message due to: " + re.reason + "\n   " + re.m.summary());
 258                         conn.println("501 " + re.reason);
 259                     }
 260                 } else                    { conn.println("500 unrecognized command"); }
 261             } catch (Message.Malformed e) { conn.println("501 " + e.toString()); }
 262         }
 263     }
 264
 265
 266     // Outgoing Mail Thread //////////////////////////////////////////////////////////////////////////////
 267
 268     public static class Outgoing extends Thread {
 269
 270         private static final HashMap deadHosts = new HashMap();
 271         public static void enqueue(Message m) throws IOException {
 272             if (m == null) { Log.warn(Outgoing.class, "attempted to enqueue(null)"); return; }
 273             String traces = m.headers.get("Received");
 274             if (traces!=null) {
 275                 int lines = 0;
 276                 for(int i=0; i<traces.length(); i++)
 277                     if (traces.charAt(i)=='\n' || traces.charAt(i)=='\r')
 278                         lines++;
 279                 if (lines > 100) { // required by rfc
 280                     Log.warn(SMTP.Outgoing.class, "Message with " + lines + " trace hops; dropping\n" + m.summary());
 281                     return;
 282                 }
 283             }
 284             synchronized(Outgoing.class) {
 285                 spool.insert(m, Mailbox.Flag.defaultFlags);
 286                 Outgoing.class.notifyAll();
 287             }
 288         }
 289
 290         public static boolean attempt(Message m) throws IOException { return attempt(m, false); }
 291         public static boolean attempt(Message m, boolean noBounces) throws IOException {
 292             if (m.envelopeTo == null) {
 293                 Log.warn(SMTP.Outgoing.class, "aieeee, null envelopeTo: " + m.summary());
 294                 return false;
 295             }
 296             InetAddress[] mx = getMailExchangerIPs(m.envelopeTo.host);
 297             if (mx.length == 0) {
 298                 if (!noBounces) {
 299                     enqueue(m.bounce("could not resolve " + m.envelopeTo.host));
 300                     return true;
 301                 } else {
 302                     Log.warn(SMTP.Outgoing.class, "could not resolve " + m.envelopeTo.host);
 303                     return false;
 304                 }
 305             }
 306             if (new Date().getTime() - m.arrival.getTime() > 1000 * 60 * 60 * 24 * 5) {
 307                 if (!noBounces) {
 308                     enqueue(m.bounce("could not send for 5 days"));
 309                     return true;
 310                 } else {
 311                     Log.warn(SMTP.Outgoing.class, "could not send for 5 days: " + m.summary());
 312                     return false;
 313                 }
 314             }
 315             for(int i=0; i<mx.length; i++) {
 316                 //if (deadHosts.contains(mx[i])) continue;
 317                 if (attempt(m, mx[i])) { return true; }
 318             }
 319             return false;
 320         }
 321
 322         private static void check(String s, Connection conn) {
 323             if (s==null) return;
 324             while (s.length() > 3 && s.charAt(3) == '-') s = conn.readln();
 325             if (s.startsWith("4")||s.startsWith("5")) throw new SMTPException(s);
 326         }
 327         private static boolean attempt(final Message m, final InetAddress mx) {
 328             boolean accepted = false;
 329             Connection conn = null;
 330             try {
 331                 conn = new Connection(new Socket(mx, 25), InetAddress.getLocalHost().getHostName());
 332                 conn.setNewline("\r\n");
 333                 conn.setTimeout(60 * 1000);
 334                 check(conn.readln(), conn);  // banner
 335                 try {
 336                     conn.println("EHLO " + conn.vhost);
 337                     check(conn.readln(), conn);
 338                 } catch (SMTPException smtpe) {
 339                     conn.println("HELO " + conn.vhost);
 340                     check(conn.readln(), conn);
 341                 }
 342                 if (m.envelopeFrom==null) {
 343                     Log.warn("", "MAIL FROM:<>");
 344                     conn.println("MAIL FROM:<>");  check(conn.readln(), conn);
 345                 } else {
 346                     Log.warn("", "MAIL FROM:<" + m.envelopeFrom.toString()+">");
 347                     conn.println("MAIL FROM:<" + m.envelopeFrom.toString()+">");  check(conn.readln(), conn);
 348                 }
 349                 conn.println("RCPT TO:<"   + m.envelopeTo.toString()+">");      check(conn.readln(), conn);
 350                 conn.println("DATA");                          check(conn.readln(), conn);
 351                 Headers head = m.headers;
 352                 head = head.remove("return-path");
 353                 head = head.remove("bcc");
 354                 Stream stream = head.getStream();
 355                 for(String s = stream.readln(); s!=null; s=stream.readln()) {
 356                     if (s.startsWith(".")) conn.print(".");
 357                     conn.println(s);
 358                 }
 359                 conn.println("");
 360                 stream = m.getBody().getStream();
 361                 for(String s = stream.readln(); s!=null; s=stream.readln()) {
 362                     if (s.startsWith(".")) conn.print(".");
 363                     conn.println(s);
 364                 }
 365                 conn.println(".");
 366                 String resp = conn.readln();
 367                 if (resp == null)
 368                     throw new SMTPException("server " + mx + " closed connection without accepting message");
 369                 check(resp, conn);
 370                 Log.warn(SMTP.Outgoing.class, "success: " + mx + " accepted " + m.summary() + "\n["+resp+"]");
 371                 accepted = true;
 372                 conn.close();
 373             } catch (SMTPException e) {
 374                 if (accepted) return true;
 375                 Log.warn(SMTP.Outgoing.class, "    unable to send; error=" + e);
 376                 Log.warn(SMTP.Outgoing.class, "      message: " + m.summary());
 377                 Log.warn(SMTP.Outgoing.class, e);
 378                 if (e.code >= 500 && e.code <= 599) {
 379                     try {
 380                         attempt(m.bounce("unable to deliver: " + e), true);
 381                     } catch (Exception ex) {
 382                         Log.error(SMTP.Outgoing.class, "exception while trying to deliver bounce; giving up completely");
 383                         Log.error(SMTP.Outgoing.class, ex);
 384                     }
 385                     return true;
 386                 }
 387                 return false;
 388             } catch (Exception e) {
 389                 if (accepted) return true;
 390                 Log.warn(SMTP.Outgoing.class, "    unable to send; error=" + e);
 391                 Log.warn(SMTP.Outgoing.class, "      message: " + m.summary());
 392                 Log.warn(SMTP.Outgoing.class, e);
 393                 if (conn != null) Log.warn(SMTP.Outgoing.class, conn.dumpLog());
 394                 return false;
 395             } finally {
 396                 if (conn != null) conn.close();
 397             }
 398             return accepted;
 399         }
 400
 401         private static HashSet<Outgoing> threads = new HashSet<Outgoing>();
 402         private static int serials = 1;
 403         private int serial = serials++;
 404         private Mailbox.Iterator it;
 405
 406         public Outgoing() {
 407             synchronized(Outgoing.class) {
 408                 threads.add(this);
 409             }
 410         }
 411
 412         public void wake() {
 413             int count = spool.count(Query.all());
 414             Log.info(SMTP.Outgoing.class, "outgoing thread #"+serial+" woke up; " + count + " messages to send");
 415             try {
 416                 while(true) {
 417                     boolean good = false;
 418                     synchronized(Outgoing.class) {
 419                         it = spool.iterator();
 420                         OUTER: for(; it.next(); ) {
 421                             for(Outgoing o : threads)
 422                                 if (o!=this && o.it != null && o.it.uid()==it.uid())
 423                                     continue OUTER;
 424                             good = true;
 425                             break;
 426                         }
 427                     }
 428                     if (!good) break;
 429                     try {
 430                         if (attempt(it.cur())) it.delete();
 431                     } catch (Exception e) {
 432                         Log.error(SMTP.Outgoing.class, e);
 433                     }
 434                     Log.info(this, "sleeping for 3s...");
 435                     Thread.sleep(3000);
 436                 }
 437             } catch (Exception e) {
 438                 //if (e instanceof InterruptedException) throw e;
 439                 Log.error(SMTP.Outgoing.class, e);
 440             }
 441             Log.info(SMTP.Outgoing.class, "outgoing thread #"+serial+" going back to sleep");
 442             it = null;
 443         }
 444
 445         public void run() {
 446             try {
 447                 while(true) {
 448                     Log.setThreadAnnotation("[outgoing #"+serial+"] ");
 449                     wake();
 450                     Thread.sleep(1000);
 451                     synchronized(Outgoing.class) {
 452                         Outgoing.class.wait(5 * 60 * 1000);
 453                     }
 454                 }
 455             } catch (InterruptedException e) { Log.warn(this, e); }
 456         }
 457     }
 458
 459     public static InetAddress[] getMailExchangerIPs(String hostName) {
 460         InetAddress[] ret;
 461         try {
 462             Hashtable env = new Hashtable();
 463             env.put("java.naming.factory.initial", "com.sun.jndi.dns.DnsContextFactory");
 464             DirContext ictx = new InitialDirContext(env);
 465             Attributes attrs = ictx.getAttributes(hostName, new String[] { "MX" });
 466             Attribute attr = attrs.get("MX");
 467             if (attr == null) {
 468                 ret = new InetAddress[1];
 469                 try {
 470                     ret[0] = InetAddress.getByName(hostName);
 471                     if (ret[0].equals(IP.getIP(127,0,0,1)) || ret[0].isLoopbackAddress()) throw new UnknownHostException();
 472                     return ret;
 473                 } catch (UnknownHostException uhe) {
 474                     Log.warn(SMTP.class, "no MX hosts or A record for " + hostName);
 475                     return new InetAddress[0];
 476                 }
 477             } else {
 478                 ret = new InetAddress[attr.size()];
 479                 NamingEnumeration ne = attr.getAll();
 480                 for(int i=0; ne.hasMore();) {
 481                     String mx = (String)ne.next();
 482                     // FIXME we should be sorting here
 483                     mx = mx.substring(mx.indexOf(" ") + 1);
 484                     if (mx.charAt(mx.length() - 1) == '.') mx = mx.substring(0, mx.length() - 1);
 485                     InetAddress ia = InetAddress.getByName(mx);
 486                     if (ia.equals(IP.getIP(127,0,0,1)) || ia.isLoopbackAddress()) continue;
 487                     ret[i++] = ia;
 488                 }
 489             }
 490         } catch (Exception e) {
 491             Log.warn(SMTP.class, "couldn't find MX host for " + hostName + " due to");
 492             Log.warn(SMTP.class, e);
 493             return new InetAddress[0];
 494         }
 495         return ret;
 496     }
 497 }