src/org/ibex/mail/protocol/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.protocol;
   6 import org.ibex.mail.*;
   7 import org.ibex.mail.target.*;
   8 import org.ibex.util.*;
   9 import org.ibex.net.*;
  10 import org.ibex.io.*;
  11 import java.net.*;
  12 import java.io.*;
  13 import java.util.*;
  14 import java.text.*;
  15 import javax.naming.*;
  16 import javax.naming.directory.*;
  17
  18 // FIXME: logging: current logging sucks
  19 // FIXME: loop prevention
  20 // FIXME: probably need some throttling on outbound mail
  21
  22 // FEATURE: infer messageid, date, if not present (?)
  23 // FEATURE: exponential backoff on retry time?
  24 // FEATURE: RFC2822, section 4.5.1: special "postmaster" address
  25 // FEATURE: RFC2822, section 4.5.4.1: retry strategies
  26 // FEATURE: RFC2822, section 5, multiple MX records, preferences, ordering
  27 // FEATURE: RFC2822, end of 4.1.2: backslashes in headers
  28 public class SMTP {
  29
  30     public static final SimpleDateFormat dateFormat = new SimpleDateFormat("EEE, d MMM yyyy HH:mm:ss Z");
  31     public static final int numOutgoingThreads = 5;
  32
  33     public static final int GRAYLIST_MINWAIT =  1000 * 60 * 60;           // one hour
  34     public static final int GRAYLIST_MAXWAIT =  1000 * 60 * 60 * 24 * 5;  // five days
  35
  36     public static final Graylist graylist =
  37         new Graylist(Mailbox.STORAGE_ROOT+"/db/graylist.sqlite");
  38
  39     public static final int MAX_MESSAGE_SIZE =
  40         Integer.parseInt(System.getProperty("org.ibex.mail.smtp.maxMessageSize", "-1"));
  41
  42     private static final Mailbox spool =
  43         FileBasedMailbox.getFileBasedMailbox(Mailbox.STORAGE_ROOT,false).slash("spool",true).slash("smtp",true);
  44
  45     static {
  46         for(int i=0; i<numOutgoingThreads; i++)
  47             new Outgoing().start();
  48     }
  49
  50     public static void accept(Message m) throws IOException {
  51         if (!m.envelopeTo.isLocal()) Outgoing.accept(m);
  52         else                         Target.root.accept(m);
  53     }
  54
  55     public static class SMTPException extends MailException {
  56         int code;
  57         String message;
  58         public SMTPException(String s) {
  59             try {
  60                 code = Integer.parseInt(s.substring(0, s.indexOf(' ')));
  61                 message = s.substring(s.indexOf(' ')+1);
  62             } catch (NumberFormatException nfe) {
  63                 code = -1;
  64                 message = s;
  65             }
  66         }
  67         public String toString() { return "SMTP " + code + ": " + message; }
  68         public String getMessage() { return toString(); }
  69     }
  70
  71     // Server //////////////////////////////////////////////////////////////////////////////
  72
  73     public static class Server {
  74         public void handleRequest(Connection conn) {
  75             conn.setTimeout(5 * 60 * 1000);
  76             conn.setNewline("\r\n");
  77             conn.println("220 " + conn.vhost + " SMTP " + this.getClass().getName());
  78             Address from = null;
  79             Vector to = new Vector();
  80             boolean ehlo = false;
  81             String remotehost = null;
  82             for(String command = conn.readln(); ; command = conn.readln()) try {
  83                 if (command == null) return;
  84                 Log.warn("**"+conn.getRemoteAddress()+"**", command);
  85                 String c = command.toUpperCase();
  86                 if (c.startsWith("HELO"))        {
  87                     remotehost = c.substring(5).trim();
  88                     conn.println("250 HELO " + conn.vhost);
  89                     from = null; to = new Vector();
  90                 } else if (c.startsWith("EHLO")) {
  91                     remotehost = c.substring(5).trim();
  92                     conn.println("250 "+conn.vhost+" greets " + remotehost);
  93                     ehlo = true;
  94                     from = null; to = new Vector();
  95                 } else if (c.startsWith("RSET")) { conn.println("250 reset ok");           from = null; to = new Vector();
  96                 } else if (c.startsWith("HELP")) { conn.println("214 you are beyond help.  see a trained professional.");
  97                 } else if (c.startsWith("VRFY")) { conn.println("502 VRFY not supported");
  98                 } else if (c.startsWith("EXPN")) { conn.println("502 EXPN not supported");
  99                 } else if (c.startsWith("NOOP")) { conn.println("250 OK");
 100                 } else if (c.startsWith("QUIT")) { conn.println("221 " + conn.vhost + " closing connection"); return;
 101                 } else if (c.startsWith("MAIL FROM:")) {
 102                     command = command.substring(10).trim();
 103                     from = command.equals("<>") ? null : new Address(command);
 104                     conn.println("250 " + from + " is syntactically correct");
 105                 } else if (c.startsWith("RCPT TO:")) {
 106                     // some clients are broken and put RCPT first; we will tolerate this
 107                     command = command.substring(8).trim();
 108                     if(command.indexOf(' ') != -1) command = command.substring(0, command.indexOf(' '));
 109                     Address addr = new Address(command);
 110                     /*
 111                     Log.warn("**"+conn.getRemoteAddress()+"**",
 112                              "addr.isLocal(): " + addr.isLocal() + "\n" +
 113                              "conn.getRemoteAddress().isLoopbackAddress(): " + conn.getRemoteAddress().isLoopbackAddress() + "\n" +
 114                              "johnw: " + (from!=null&&from.toString().indexOf("johnw")!=-1) + "\n"
 115                              );
 116                     */
 117                     if (addr.isLocal()) {
 118                         // FEATURE: should check the address further and give 550 if undeliverable
 119                         conn.println("250 " + addr + " is on this machine; I will deliver it");
 120                         to.addElement(addr);
 121                     } else if (conn.getRemoteAddress().isLoopbackAddress() || (from!=null&&from.toString().indexOf("johnw")!=-1)) {
 122                         conn.println("250 you are connected locally, so I will let you send");
 123                         to.addElement(addr);
 124                     } else {
 125                         conn.println("551 sorry, " + addr + " is not on this machine");
 126                     }
 127                     conn.flush();
 128                 } else if (c.startsWith("DATA")) {
 129                     //if (from == null) { conn.println("503 MAIL FROM command must precede DATA"); continue; }
 130                     if (to == null || to.size()==0) { conn.println("503 RCPT TO command must precede DATA"); continue; }
 131                     if (!graylist.isWhitelisted(conn.getRemoteAddress()) && !conn.getRemoteAddress().isLoopbackAddress()) {
 132                         long when = graylist.getGrayListTimestamp(conn.getRemoteAddress(), from+"", to+"");
 133                         if (when == 0 || System.currentTimeMillis() - when > GRAYLIST_MAXWAIT) {
 134                             graylist.setGrayListTimestamp(conn.getRemoteAddress(), from+"", to+"",  System.currentTimeMillis());
 135                             conn.println("451 you are graylisted; please try back in one hour to be whitelisted");
 136                             Log.warn(conn.getRemoteAddress().toString(), "451 you are graylisted; please try back in one hour to be whitelisted");
 137                             conn.flush();
 138                             continue;
 139                         } else if (System.currentTimeMillis() - when > GRAYLIST_MINWAIT) {
 140                             graylist.addWhitelist(conn.getRemoteAddress());
 141                             conn.println("354 (you have been whitelisted) Enter message, ending with \".\" on a line by itself");
 142                             Log.warn(conn.getRemoteAddress().toString(), "has been whitelisted");
 143                         } else {
 144                             conn.println("451 you are still graylisted (since "+new java.util.Date(when)+")");
 145                             conn.flush();
 146                             Log.warn(conn.getRemoteAddress().toString(), "451 you are still graylisted (since "+new java.util.Date(when)+")");
 147                             continue;
 148                         }
 149                     } else {
 150                         conn.println("354 Enter message, ending with \".\" on a line by itself");
 151                     }
 152                     conn.flush();
 153                     try {
 154                         StringBuffer buf = new StringBuffer();
 155                         buf.append("Received: from " + conn.getRemoteHostname() + " (" + remotehost + ")\r\n");
 156                         buf.append("          by "+conn.vhost+" ("+SMTP.class.getName()+") with "+(ehlo?"ESMTP":"SMTP") + "\r\n");
 157                         buf.append("          for ");
 158                         // FIXME: this is leaking BCC addrs
 159                         // for(int i=0; i<to.size(); i++) buf.append(to.elementAt(i) + " ");
 160                         buf.append("; " + dateFormat.format(new Date()) + "\r\n");
 161                         while(true) {
 162                             String s = conn.readln();
 163                             if (s == null) throw new RuntimeException("connection closed");
 164                             if (s.equals(".")) break;
 165                             if (s.startsWith(".")) s = s.substring(1);
 166                             buf.append(s + "\r\n");
 167                             if (MAX_MESSAGE_SIZE != -1 && buf.length() > MAX_MESSAGE_SIZE) {
 168                                 Log.error("**"+conn.getRemoteAddress()+"**",
 169                                           "sorry, this mail server only accepts messages of less than " +
 170                                           ByteSize.toString(MAX_MESSAGE_SIZE));
 171                                 throw new MailException.Malformed("sorry, this mail server only accepts messages of less than " +
 172                                                                   ByteSize.toString(MAX_MESSAGE_SIZE));
 173                             }
 174                         }
 175                         String body = buf.toString();
 176                         Message m = null;
 177                         for(int i=0; i<to.size(); i++) {
 178                             m = Message.newMessage(new Fountain.StringFountain(body), from, (Address)to.elementAt(i));
 179                             accept(m);
 180                         }
 181                         if (m != null) Log.info(SMTP.class, "accepted message: " + m.summary());
 182                         conn.println("250 message accepted");
 183                         conn.flush();
 184                         from = null; to = new Vector();
 185                     } catch (Reject.RejectException re) {
 186                         Log.warn(SMTP.class, "rejecting message due to: " + re.reason + "\n   " + re.m.summary());
 187                         conn.println("501 " + re.reason);
 188                     } catch (MailException.Malformed mfe) {   conn.println("501 " + mfe.toString());
 189                     } catch (MailException.MailboxFull mbf) { conn.println("452 " + mbf);
 190                     } catch (Later.LaterException le) {       conn.println("453 try again later");
 191                     } catch (IOException ioe) {
 192                         //conn.println("554 " + ioe.toString());
 193                         Log.error(this, ioe);
 194                         conn.close();
 195                         return;
 196                     }
 197                 } else                    { conn.println("500 unrecognized command"); }
 198             } catch (Message.Malformed e) { conn.println("501 " + e.toString()); }
 199         }
 200     }
 201
 202
 203     // Outgoing Mail Thread //////////////////////////////////////////////////////////////////////////////
 204
 205     public static class Outgoing extends Thread {
 206
 207         private static final HashMap deadHosts = new HashMap();
 208         public static void accept(Message m) throws IOException {
 209             if (m == null) { Log.warn(Outgoing.class, "attempted to accept(null)"); return; }
 210             String traces = m.headers.get("Received");
 211             if (traces!=null) {
 212                 int lines = 0;
 213                 for(int i=0; i<traces.length(); i++)
 214                     if (traces.charAt(i)=='\n' || traces.charAt(i)=='\r')
 215                         lines++;
 216                 if (lines > 100) { // required by rfc
 217                     Log.warn(SMTP.Outgoing.class, "Message with " + lines + " trace hops; dropping\n" + m.summary());
 218                     return;
 219                 }
 220             }
 221             synchronized(Outgoing.class) {
 222                 spool.add(m);
 223                 Outgoing.class.notifyAll();
 224             }
 225         }
 226
 227         public static boolean attempt(Message m) throws IOException { return attempt(m, false); }
 228         public static boolean attempt(Message m, boolean noBounces) throws IOException {
 229             if (m.envelopeTo == null) {
 230                 Log.warn(SMTP.Outgoing.class, "aieeee, null envelopeTo: " + m.summary());
 231                 return false;
 232             }
 233             InetAddress[] mx = getMailExchangerIPs(m.envelopeTo.host);
 234             if (mx.length == 0) {
 235                 if (!noBounces) {
 236                     accept(m.bounce("could not resolve " + m.envelopeTo.host));
 237                     return true;
 238                 } else {
 239                     Log.warn(SMTP.Outgoing.class, "could not resolve " + m.envelopeTo.host);
 240                     return false;
 241                 }
 242             }
 243             if (new Date().getTime() - m.arrival.getTime() > 1000 * 60 * 60 * 24 * 5) {
 244                 if (!noBounces) {
 245                     accept(m.bounce("could not send for 5 days"));
 246                     return true;
 247                 } else {
 248                     Log.warn(SMTP.Outgoing.class, "could not send for 5 days: " + m.summary());
 249                     return false;
 250                 }
 251             }
 252             for(int i=0; i<mx.length; i++) {
 253                 //if (deadHosts.contains(mx[i])) continue;
 254                 if (attempt(m, mx[i])) { return true; }
 255             }
 256             return false;
 257         }
 258
 259         private static void check(String s, Connection conn) {
 260             if (s==null) return;
 261             while (s.length() > 3 && s.charAt(3) == '-') s = conn.readln();
 262             if (s.startsWith("4")||s.startsWith("5")) throw new SMTPException(s);
 263         }
 264         private static boolean attempt(final Message m, final InetAddress mx) {
 265             boolean accepted = false;
 266             Connection conn = null;
 267             try {
 268                 Log.note("connecting to " + mx + "...");
 269                 conn = new Connection(new Socket(mx, 25), InetAddress.getLocalHost().getHostName());
 270                 conn.setNewline("\r\n");
 271                 conn.setTimeout(60 * 1000);
 272                 Log.note("    connected");
 273                 check(conn.readln(), conn);  // banner
 274                 try {
 275                     conn.println("EHLO " + conn.vhost);
 276                     check(conn.readln(), conn);
 277                 } catch (SMTPException smtpe) {
 278                     conn.println("HELO " + conn.vhost);
 279                     check(conn.readln(), conn);
 280                 }
 281                 if (m.envelopeFrom==null) {
 282                     Log.warn("", "MAIL FROM:<>");
 283                     conn.println("MAIL FROM:<>");  check(conn.readln(), conn);
 284                 } else {
 285                     Log.warn("", "MAIL FROM:<" + m.envelopeFrom.toString()+">");
 286                     conn.println("MAIL FROM:<" + m.envelopeFrom.toString()+">");  check(conn.readln(), conn);
 287                 }
 288                 conn.println("RCPT TO:<"   + m.envelopeTo.toString()+">");      check(conn.readln(), conn);
 289                 conn.println("DATA");                          check(conn.readln(), conn);
 290                 Headers head = m.headers;
 291                 head = head.remove("return-path");
 292                 head = head.remove("bcc");
 293                 Stream stream = head.getStream();
 294                 for(String s = stream.readln(); s!=null; s=stream.readln()) {
 295                     if (s.startsWith(".")) conn.print(".");
 296                     conn.println(s);
 297                 }
 298                 conn.println("");
 299                 stream = m.getBody().getStream();
 300                 for(String s = stream.readln(); s!=null; s=stream.readln()) {
 301                     if (s.startsWith(".")) conn.print(".");
 302                     conn.println(s);
 303                 }
 304                 conn.println(".");
 305                 String resp = conn.readln();
 306                 if (resp == null)
 307                     throw new SMTPException("server " + mx + " closed connection without accepting message");
 308                 check(resp, conn);
 309                 Log.warn(SMTP.Outgoing.class, "success: " + mx + " accepted " + m.summary() + "\n["+resp+"]");
 310                 accepted = true;
 311                 conn.close();
 312             } catch (SMTPException e) {
 313                 if (accepted) return true;
 314                 Log.warn(SMTP.Outgoing.class, "    unable to send; error=" + e);
 315                 Log.warn(SMTP.Outgoing.class, "      message: " + m.summary());
 316                 Log.warn(SMTP.Outgoing.class, e);
 317                 if (e.code >= 500 && e.code <= 599) {
 318                     try {
 319                         attempt(m.bounce("unable to deliver: " + e), true);
 320                     } catch (Exception ex) {
 321                         Log.error(SMTP.Outgoing.class, "exception while trying to deliver bounce; giving up completely");
 322                         Log.error(SMTP.Outgoing.class, ex);
 323                     }
 324                     return true;
 325                 }
 326                 return false;
 327             } catch (Exception e) {
 328                 if (accepted) return true;
 329                 Log.warn(SMTP.Outgoing.class, "    unable to send; error=" + e);
 330                 Log.warn(SMTP.Outgoing.class, "      message: " + m.summary());
 331                 Log.warn(SMTP.Outgoing.class, e);
 332                 if (conn != null) Log.warn(SMTP.Outgoing.class, conn.dumpLog());
 333                 return false;
 334             } finally {
 335                 if (conn != null) conn.close();
 336             }
 337             return accepted;
 338         }
 339
 340         private static HashSet<Outgoing> threads = new HashSet<Outgoing>();
 341         private static int serials = 1;
 342         private int serial = serials++;
 343         private Mailbox.Iterator it;
 344
 345         public Outgoing() {
 346             synchronized(Outgoing.class) {
 347                 threads.add(this);
 348             }
 349         }
 350
 351         public void wake() {
 352             int count = spool.count(Query.all());
 353             Log.info(SMTP.Outgoing.class, "outgoing thread #"+serial+" woke up; " + count + " messages to send");
 354             try {
 355                 while(true) {
 356                     boolean good = false;
 357                     synchronized(Outgoing.class) {
 358                         it = spool.iterator();
 359                         OUTER: for(; it.next(); ) {
 360                             for(Outgoing o : threads)
 361                                 if (o!=this && o.it != null && o.it.uid()==it.uid())
 362                                     continue OUTER;
 363                             good = true;
 364                             break;
 365                         }
 366                     }
 367                     if (!good) break;
 368                     try {
 369                         if (attempt(it.cur())) it.delete();
 370                     } catch (Exception e) {
 371                         Log.error(SMTP.Outgoing.class, e);
 372                     }
 373                     Log.info(this, "sleeping for 3s...");
 374                     Thread.sleep(3000);
 375                 }
 376             } catch (Exception e) {
 377                 //if (e instanceof InterruptedException) throw e;
 378                 Log.error(SMTP.Outgoing.class, e);
 379             }
 380             Log.info(SMTP.Outgoing.class, "outgoing thread #"+serial+" going back to sleep");
 381             it = null;
 382         }
 383
 384         public void run() {
 385             try {
 386                 while(true) {
 387                     Log.setThreadAnnotation("[outgoing #"+serial+"] ");
 388                     wake();
 389                     Thread.sleep(1000);
 390                     synchronized(Outgoing.class) {
 391                         Outgoing.class.wait(5 * 60 * 1000);
 392                     }
 393                 }
 394             } catch (InterruptedException e) { Log.warn(this, e); }
 395         }
 396     }
 397
 398     public static InetAddress[] getMailExchangerIPs(String hostName) {
 399         InetAddress[] ret;
 400         try {
 401             Hashtable env = new Hashtable();
 402             env.put("java.naming.factory.initial", "com.sun.jndi.dns.DnsContextFactory");
 403             DirContext ictx = new InitialDirContext(env);
 404             Attributes attrs = ictx.getAttributes(hostName, new String[] { "MX" });
 405             Attribute attr = attrs.get("MX");
 406             if (attr == null) {
 407                 ret = new InetAddress[1];
 408                 try {
 409                     ret[0] = InetAddress.getByName(hostName);
 410                     if (ret[0].equals(IP.getIP(127,0,0,1)) || ret[0].isLoopbackAddress()) throw new UnknownHostException();
 411                     return ret;
 412                 } catch (UnknownHostException uhe) {
 413                     Log.warn(SMTP.class, "no MX hosts or A record for " + hostName);
 414                     return new InetAddress[0];
 415                 }
 416             } else {
 417                 ret = new InetAddress[attr.size()];
 418                 NamingEnumeration ne = attr.getAll();
 419                 for(int i=0; ne.hasMore();) {
 420                     String mx = (String)ne.next();
 421                     // FIXME we should be sorting here
 422                     mx = mx.substring(mx.indexOf(" ") + 1);
 423                     if (mx.charAt(mx.length() - 1) == '.') mx = mx.substring(0, mx.length() - 1);
 424                     InetAddress ia = InetAddress.getByName(mx);
 425                     if (ia.equals(IP.getIP(127,0,0,1)) || ia.isLoopbackAddress()) continue;
 426                     ret[i++] = ia;
 427                 }
 428             }
 429         } catch (Exception e) {
 430             Log.warn(SMTP.class, "couldn't find MX host for " + hostName + " due to");
 431             Log.warn(SMTP.class, e);
 432             return new InetAddress[0];
 433         }
 434         return ret;
 435     }
 436 }