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: infer messageid, date, if not present (?)
  31 // FEATURE: exponential backoff on retry time?
  32 // FEATURE: RFC2822, section 4.5.1: special "postmaster" address
  33 // FEATURE: RFC2822, section 4.5.4.1: retry strategies
  34 // FEATURE: RFC2822, section 5, multiple MX records, preferences, ordering
  35 // FEATURE: RFC2822, end of 4.1.2: backslashes in headers
  36 public class SMTP {
  37
  38     public static final SimpleDateFormat dateFormat = new SimpleDateFormat("EEE, d MMM yyyy HH:mm:ss Z");
  39     public static final int numOutgoingThreads = 5;
  40
  41     public static final int GRAYLIST_MINWAIT =  1000 * 60 * 60;           // one hour
  42     public static final int GRAYLIST_MAXWAIT =  1000 * 60 * 60 * 24 * 5;  // five days
  43
  44     public static final Graylist graylist =
  45         new Graylist(Mailbox.STORAGE_ROOT+"/db/graylist.sqlite");
  46
  47     public static final Whitelist whitelist =
  48         new Whitelist(Mailbox.STORAGE_ROOT+"/db/whitelist.sqlite");
  49
  50     public static final int MAX_MESSAGE_SIZE =
  51         Integer.parseInt(System.getProperty("org.ibex.mail.smtp.maxMessageSize", "-1"));
  52
  53     private static final Mailbox spool =
  54         FileBasedMailbox.getFileBasedMailbox(Mailbox.STORAGE_ROOT,false).slash("spool",true).slash("smtp",true);
  55
  56     static {
  57         for(int i=0; i<numOutgoingThreads; i++)
  58             new Outgoing().start();
  59     }
  60
  61     public static void accept(Message m) throws IOException {
  62         if (!m.envelopeTo.isLocal()) Outgoing.accept(m);
  63         else                         Target.root.accept(m);
  64     }
  65
  66     public static class SMTPException extends MailException {
  67         int code;
  68         String message;
  69         public SMTPException(String s) {
  70             try {
  71                 code = Integer.parseInt(s.substring(0, s.indexOf(' ')));
  72                 message = s.substring(s.indexOf(' ')+1);
  73             } catch (NumberFormatException nfe) {
  74                 code = -1;
  75                 message = s;
  76             }
  77         }
  78         public String toString() { return "SMTP " + code + ": " + message; }
  79         public String getMessage() { return toString(); }
  80     }
  81
  82     // Server //////////////////////////////////////////////////////////////////////////////
  83
  84     public static class Server {
  85         public void handleRequest(Connection conn) throws IOException {
  86             conn.setTimeout(5 * 60 * 1000);
  87             conn.setNewline("\r\n");
  88             conn.println("220 " + conn.vhost + " SMTP " + this.getClass().getName());
  89             Address from = null;
  90             Vector to = new Vector();
  91             boolean ehlo = false;
  92             String remotehost = null;
  93             for(String command = conn.readln(); ; command = conn.readln()) try {
  94                 if (command == null) return;
  95                 //Log.warn("**"+conn.getRemoteAddress()+"**", command);
  96                 String c = command.toUpperCase();
  97                 if (c.startsWith("HELO"))        {
  98                     remotehost = c.substring(5).trim();
  99                     conn.println("250 HELO " + conn.vhost);
 100                     from = null; to = new Vector();
 101                 } else if (c.startsWith("EHLO")) {
 102                     remotehost = c.substring(5).trim();
 103                     conn.println("250 "+conn.vhost+" greets " + remotehost);
 104                     ehlo = true;
 105                     from = null; to = new Vector();
 106                 } else if (c.startsWith("RSET")) { conn.println("250 reset ok");           from = null; to = new Vector();
 107                 } else if (c.startsWith("HELP")) { conn.println("214 you are beyond help.  see a trained professional.");
 108                 } else if (c.startsWith("VRFY")) { conn.println("502 VRFY not supported");
 109                 } else if (c.startsWith("EXPN")) { conn.println("502 EXPN not supported");
 110                 } else if (c.startsWith("NOOP")) { conn.println("250 OK");
 111                 } else if (c.startsWith("QUIT")) { conn.println("221 " + conn.vhost + " closing connection"); return;
 112                 } else if (c.startsWith("MAIL FROM:")) {
 113                     command = command.substring(10).trim();
 114                     from = command.equals("<>") ? null : new Address(command);
 115                     conn.println("250 " + from + " is syntactically correct");
 116                 } else if (c.startsWith("RCPT TO:")) {
 117                     // some clients are broken and put RCPT first; we will tolerate this
 118                     command = command.substring(8).trim();
 119                     if(command.indexOf(' ') != -1) command = command.substring(0, command.indexOf(' '));
 120                     Address addr = new Address(command);
 121                     /*
 122                     Log.warn("**"+conn.getRemoteAddress()+"**",
 123                              "addr.isLocal(): " + addr.isLocal() + "\n" +
 124                              "conn.getRemoteAddress().isLoopbackAddress(): " + conn.getRemoteAddress().isLoopbackAddress() + "\n" +
 125                              "johnw: " + (from!=null&&from.toString().indexOf("johnw")!=-1) + "\n"
 126                              );
 127                     */
 128                     if (addr.isLocal()) {
 129                         // FEATURE: should check the address further and give 550 if undeliverable
 130                         conn.println("250 " + addr + " is on this machine; I will deliver it");
 131                         to.addElement(addr);
 132                     } else if (conn.getRemoteAddress().isLoopbackAddress() || (from!=null&&from.toString().indexOf("johnw")!=-1)) {
 133                         conn.println("250 you are connected locally, so I will let you send");
 134                         to.addElement(addr);
 135                     } else {
 136                         conn.println("551 sorry, " + addr + " is not on this machine");
 137                     }
 138                     conn.flush();
 139                 } else if (c.startsWith("DATA")) {
 140                     //if (from == null) { conn.println("503 MAIL FROM command must precede DATA"); continue; }
 141                     if (to == null || to.size()==0) { conn.println("503 RCPT TO command must precede DATA"); continue; }
 142                     if (!graylist.isWhitelisted(conn.getRemoteAddress()) && !conn.getRemoteAddress().isLoopbackAddress()) {
 143                         long when = graylist.getGrayListTimestamp(conn.getRemoteAddress(), from+"", to+"");
 144                         if (when == 0 || System.currentTimeMillis() - when > GRAYLIST_MAXWAIT) {
 145                             graylist.setGrayListTimestamp(conn.getRemoteAddress(), from+"", to+"",  System.currentTimeMillis());
 146                             conn.println("451 you are graylisted; please try back in one hour to be whitelisted");
 147                             Log.warn(conn.getRemoteAddress().toString(), "451 you are graylisted; please try back in one hour to be whitelisted");
 148                             conn.flush();
 149                             continue;
 150                         } else if (System.currentTimeMillis() - when > GRAYLIST_MINWAIT) {
 151                             graylist.addWhitelist(conn.getRemoteAddress());
 152                             conn.println("354 (you have been whitelisted) Enter message, ending with \".\" on a line by itself");
 153                             Log.warn(conn.getRemoteAddress().toString(), "has been whitelisted");
 154                         } else {
 155                             conn.println("451 you are still graylisted (since "+new java.util.Date(when)+")");
 156                             conn.flush();
 157                             Log.warn(conn.getRemoteAddress().toString(), "451 you are still graylisted (since "+new java.util.Date(when)+")");
 158                             continue;
 159                         }
 160                     } else {
 161                         conn.println("354 Enter message, ending with \".\" on a line by itself");
 162                     }
 163                     conn.flush();
 164                     try {
 165                         StringBuffer buf = new StringBuffer();
 166                         buf.append("Received: from " + conn.getRemoteHostname() + " (" + remotehost + ")\r\n");
 167                         buf.append("          by "+conn.vhost+" ("+SMTP.class.getName()+") with "+(ehlo?"ESMTP":"SMTP") + "\r\n");
 168                         buf.append("          for ");
 169                         // FIXME: this is leaking BCC addrs
 170                         // for(int i=0; i<to.size(); i++) buf.append(to.elementAt(i) + " ");
 171                         buf.append("; " + dateFormat.format(new Date()) + "\r\n");
 172                         while(true) {
 173                             String s = conn.readln();
 174                             if (s == null) throw new RuntimeException("connection closed");
 175                             if (s.equals(".")) break;
 176                             if (s.startsWith(".")) s = s.substring(1);
 177                             buf.append(s + "\r\n");
 178                             if (MAX_MESSAGE_SIZE != -1 && buf.length() > MAX_MESSAGE_SIZE) {
 179                                 Log.error("**"+conn.getRemoteAddress()+"**",
 180                                           "sorry, this mail server only accepts messages of less than " +
 181                                           ByteSize.toString(MAX_MESSAGE_SIZE));
 182                                 throw new MailException.Malformed("sorry, this mail server only accepts messages of less than " +
 183                                                                   ByteSize.toString(MAX_MESSAGE_SIZE));
 184                             }
 185                         }
 186                         String body = buf.toString();
 187                         Message m = null;
 188                         for(int i=0; i<to.size(); i++) {
 189                             m = Message.newMessage(new Fountain.StringFountain(body), from, (Address)to.elementAt(i));
 190                             accept(m);
 191                         }
 192                         if (m != null) Log.info(SMTP.class, "accepted message: " + m.summary());
 193                         conn.println("250 message accepted");
 194                         conn.flush();
 195                         from = null; to = new Vector();
 196                     } catch (MailException.Malformed mfe) {    conn.println("501 " + mfe.toString());
 197                     } catch (MailException.MailboxFull mbf) {  conn.println("452 " + mbf);
 198                     } catch (Script.Later.LaterException le) { conn.println("453 try again later");
 199                     } catch (Script.Reject.RejectException re) {
 200                         Log.warn(SMTP.class, "rejecting message due to: " + re.reason + "\n   " + re.m.summary());
 201                         conn.println("501 " + re.reason);
 202                     }
 203                 } else                    { conn.println("500 unrecognized command"); }
 204             } catch (Message.Malformed e) { conn.println("501 " + e.toString()); }
 205         }
 206     }
 207
 208
 209     // Outgoing Mail Thread //////////////////////////////////////////////////////////////////////////////
 210
 211     public static class Outgoing extends Thread {
 212
 213         private static final HashMap deadHosts = new HashMap();
 214         public static void accept(Message m) throws IOException {
 215             if (m == null) { Log.warn(Outgoing.class, "attempted to accept(null)"); return; }
 216             String traces = m.headers.get("Received");
 217             if (traces!=null) {
 218                 int lines = 0;
 219                 for(int i=0; i<traces.length(); i++)
 220                     if (traces.charAt(i)=='\n' || traces.charAt(i)=='\r')
 221                         lines++;
 222                 if (lines > 100) { // required by rfc
 223                     Log.warn(SMTP.Outgoing.class, "Message with " + lines + " trace hops; dropping\n" + m.summary());
 224                     return;
 225                 }
 226             }
 227             synchronized(Outgoing.class) {
 228                 spool.insert(m, Mailbox.Flag.defaultFlags);
 229                 Outgoing.class.notifyAll();
 230             }
 231         }
 232
 233         public static boolean attempt(Message m) throws IOException { return attempt(m, false); }
 234         public static boolean attempt(Message m, boolean noBounces) throws IOException {
 235             if (m.envelopeTo == null) {
 236                 Log.warn(SMTP.Outgoing.class, "aieeee, null envelopeTo: " + m.summary());
 237                 return false;
 238             }
 239             InetAddress[] mx = getMailExchangerIPs(m.envelopeTo.host);
 240             if (mx.length == 0) {
 241                 if (!noBounces) {
 242                     accept(m.bounce("could not resolve " + m.envelopeTo.host));
 243                     return true;
 244                 } else {
 245                     Log.warn(SMTP.Outgoing.class, "could not resolve " + m.envelopeTo.host);
 246                     return false;
 247                 }
 248             }
 249             if (new Date().getTime() - m.arrival.getTime() > 1000 * 60 * 60 * 24 * 5) {
 250                 if (!noBounces) {
 251                     accept(m.bounce("could not send for 5 days"));
 252                     return true;
 253                 } else {
 254                     Log.warn(SMTP.Outgoing.class, "could not send for 5 days: " + m.summary());
 255                     return false;
 256                 }
 257             }
 258             for(int i=0; i<mx.length; i++) {
 259                 //if (deadHosts.contains(mx[i])) continue;
 260                 if (attempt(m, mx[i])) { return true; }
 261             }
 262             return false;
 263         }
 264
 265         private static void check(String s, Connection conn) {
 266             if (s==null) return;
 267             while (s.length() > 3 && s.charAt(3) == '-') s = conn.readln();
 268             if (s.startsWith("4")||s.startsWith("5")) throw new SMTPException(s);
 269         }
 270         private static boolean attempt(final Message m, final InetAddress mx) {
 271             boolean accepted = false;
 272             Connection conn = null;
 273             try {
 274                 Log.note("connecting to " + mx + "...");
 275                 conn = new Connection(new Socket(mx, 25), InetAddress.getLocalHost().getHostName());
 276                 conn.setNewline("\r\n");
 277                 conn.setTimeout(60 * 1000);
 278                 Log.note("    connected");
 279                 check(conn.readln(), conn);  // banner
 280                 try {
 281                     conn.println("EHLO " + conn.vhost);
 282                     check(conn.readln(), conn);
 283                 } catch (SMTPException smtpe) {
 284                     conn.println("HELO " + conn.vhost);
 285                     check(conn.readln(), conn);
 286                 }
 287                 if (m.envelopeFrom==null) {
 288                     Log.warn("", "MAIL FROM:<>");
 289                     conn.println("MAIL FROM:<>");  check(conn.readln(), conn);
 290                 } else {
 291                     Log.warn("", "MAIL FROM:<" + m.envelopeFrom.toString()+">");
 292                     conn.println("MAIL FROM:<" + m.envelopeFrom.toString()+">");  check(conn.readln(), conn);
 293                 }
 294                 conn.println("RCPT TO:<"   + m.envelopeTo.toString()+">");      check(conn.readln(), conn);
 295                 conn.println("DATA");                          check(conn.readln(), conn);
 296                 Headers head = m.headers;
 297                 head = head.remove("return-path");
 298                 head = head.remove("bcc");
 299                 Stream stream = head.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                 stream = m.getBody().getStream();
 306                 for(String s = stream.readln(); s!=null; s=stream.readln()) {
 307                     if (s.startsWith(".")) conn.print(".");
 308                     conn.println(s);
 309                 }
 310                 conn.println(".");
 311                 String resp = conn.readln();
 312                 if (resp == null)
 313                     throw new SMTPException("server " + mx + " closed connection without accepting message");
 314                 check(resp, conn);
 315                 Log.warn(SMTP.Outgoing.class, "success: " + mx + " accepted " + m.summary() + "\n["+resp+"]");
 316                 accepted = true;
 317                 conn.close();
 318             } catch (SMTPException e) {
 319                 if (accepted) return true;
 320                 Log.warn(SMTP.Outgoing.class, "    unable to send; error=" + e);
 321                 Log.warn(SMTP.Outgoing.class, "      message: " + m.summary());
 322                 Log.warn(SMTP.Outgoing.class, e);
 323                 if (e.code >= 500 && e.code <= 599) {
 324                     try {
 325                         attempt(m.bounce("unable to deliver: " + e), true);
 326                     } catch (Exception ex) {
 327                         Log.error(SMTP.Outgoing.class, "exception while trying to deliver bounce; giving up completely");
 328                         Log.error(SMTP.Outgoing.class, ex);
 329                     }
 330                     return true;
 331                 }
 332                 return false;
 333             } catch (Exception e) {
 334                 if (accepted) return true;
 335                 Log.warn(SMTP.Outgoing.class, "    unable to send; error=" + e);
 336                 Log.warn(SMTP.Outgoing.class, "      message: " + m.summary());
 337                 Log.warn(SMTP.Outgoing.class, e);
 338                 if (conn != null) Log.warn(SMTP.Outgoing.class, conn.dumpLog());
 339                 return false;
 340             } finally {
 341                 if (conn != null) conn.close();
 342             }
 343             return accepted;
 344         }
 345
 346         private static HashSet<Outgoing> threads = new HashSet<Outgoing>();
 347         private static int serials = 1;
 348         private int serial = serials++;
 349         private Mailbox.Iterator it;
 350
 351         public Outgoing() {
 352             synchronized(Outgoing.class) {
 353                 threads.add(this);
 354             }
 355         }
 356
 357         public void wake() {
 358             int count = spool.count(Query.all());
 359             Log.info(SMTP.Outgoing.class, "outgoing thread #"+serial+" woke up; " + count + " messages to send");
 360             try {
 361                 while(true) {
 362                     boolean good = false;
 363                     synchronized(Outgoing.class) {
 364                         it = spool.iterator();
 365                         OUTER: for(; it.next(); ) {
 366                             for(Outgoing o : threads)
 367                                 if (o!=this && o.it != null && o.it.uid()==it.uid())
 368                                     continue OUTER;
 369                             good = true;
 370                             break;
 371                         }
 372                     }
 373                     if (!good) break;
 374                     try {
 375                         if (attempt(it.cur())) it.delete();
 376                     } catch (Exception e) {
 377                         Log.error(SMTP.Outgoing.class, e);
 378                     }
 379                     Log.info(this, "sleeping for 3s...");
 380                     Thread.sleep(3000);
 381                 }
 382             } catch (Exception e) {
 383                 //if (e instanceof InterruptedException) throw e;
 384                 Log.error(SMTP.Outgoing.class, e);
 385             }
 386             Log.info(SMTP.Outgoing.class, "outgoing thread #"+serial+" going back to sleep");
 387             it = null;
 388         }
 389
 390         public void run() {
 391             try {
 392                 while(true) {
 393                     Log.setThreadAnnotation("[outgoing #"+serial+"] ");
 394                     wake();
 395                     Thread.sleep(1000);
 396                     synchronized(Outgoing.class) {
 397                         Outgoing.class.wait(5 * 60 * 1000);
 398                     }
 399                 }
 400             } catch (InterruptedException e) { Log.warn(this, e); }
 401         }
 402     }
 403
 404     public static InetAddress[] getMailExchangerIPs(String hostName) {
 405         InetAddress[] ret;
 406         try {
 407             Hashtable env = new Hashtable();
 408             env.put("java.naming.factory.initial", "com.sun.jndi.dns.DnsContextFactory");
 409             DirContext ictx = new InitialDirContext(env);
 410             Attributes attrs = ictx.getAttributes(hostName, new String[] { "MX" });
 411             Attribute attr = attrs.get("MX");
 412             if (attr == null) {
 413                 ret = new InetAddress[1];
 414                 try {
 415                     ret[0] = InetAddress.getByName(hostName);
 416                     if (ret[0].equals(IP.getIP(127,0,0,1)) || ret[0].isLoopbackAddress()) throw new UnknownHostException();
 417                     return ret;
 418                 } catch (UnknownHostException uhe) {
 419                     Log.warn(SMTP.class, "no MX hosts or A record for " + hostName);
 420                     return new InetAddress[0];
 421                 }
 422             } else {
 423                 ret = new InetAddress[attr.size()];
 424                 NamingEnumeration ne = attr.getAll();
 425                 for(int i=0; ne.hasMore();) {
 426                     String mx = (String)ne.next();
 427                     // FIXME we should be sorting here
 428                     mx = mx.substring(mx.indexOf(" ") + 1);
 429                     if (mx.charAt(mx.length() - 1) == '.') mx = mx.substring(0, mx.length() - 1);
 430                     InetAddress ia = InetAddress.getByName(mx);
 431                     if (ia.equals(IP.getIP(127,0,0,1)) || ia.isLoopbackAddress()) continue;
 432                     ret[i++] = ia;
 433                 }
 434             }
 435         } catch (Exception e) {
 436             Log.warn(SMTP.class, "couldn't find MX host for " + hostName + " due to");
 437             Log.warn(SMTP.class, e);
 438             return new InetAddress[0];
 439         }
 440         return ret;
 441     }
 442 }