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 // graylisting?
  23
  24 // FEATURE: infer messageid, date, if not present (?)
  25 // FEATURE: exponential backoff on retry time?
  26 // FEATURE: RFC2822, section 4.5.1: special "postmaster" address
  27 // FEATURE: RFC2822, section 4.5.4.1: retry strategies
  28 // FEATURE: RFC2822, section 5, multiple MX records, preferences, ordering
  29 // FEATURE: RFC2822, end of 4.1.2: backslashes in headers
  30 public class SMTP {
  31
  32     public static final SimpleDateFormat dateFormat = new SimpleDateFormat("EEE, d MMM yyyy HH:mm:ss Z");
  33     public static final int numOutgoingThreads = 5;
  34
  35     public static final int GRAYLIST_MINWAIT =  1000 * 60 * 60;           // one hour
  36     public static final int GRAYLIST_MAXWAIT =  1000 * 60 * 60 * 24 * 5;  // five days
  37
  38     public static final Graylist graylist =
  39         new Graylist(Mailbox.STORAGE_ROOT+"/graylist.sqlite");
  40
  41     public static final int MAX_MESSAGE_SIZE =
  42         Integer.parseInt(System.getProperty("org.ibex.mail.smtp.maxMessageSize", "-1"));
  43
  44     private static final Mailbox spool =
  45         FileBasedMailbox.getFileBasedMailbox(Mailbox.STORAGE_ROOT,false).slash("spool",true).slash("smtp",true);
  46
  47     static {
  48         for(int i=0; i<numOutgoingThreads; i++)
  49             new Outgoing().start();
  50     }
  51
  52     public static void accept(Message m) throws IOException {
  53         if (!m.envelopeTo.isLocal()) Outgoing.accept(m);
  54         else                         Target.root.accept(m);
  55     }
  56
  57     public static class SMTPException extends MailException {
  58         int code;
  59         String message;
  60         public SMTPException(String s) {
  61             try {
  62                 code = Integer.parseInt(s.substring(0, s.indexOf(' ')));
  63                 message = s.substring(s.indexOf(' ')+1);
  64             } catch (NumberFormatException nfe) {
  65                 code = -1;
  66                 message = s;
  67             }
  68         }
  69         public String toString() { return "SMTP " + code + ": " + message; }
  70         public String getMessage() { return toString(); }
  71     }
  72
  73     // Server //////////////////////////////////////////////////////////////////////////////
  74
  75     public static class Server {
  76         public void handleRequest(Connection conn) {
  77             conn.setTimeout(5 * 60 * 1000);
  78             conn.setNewline("\r\n");
  79             conn.println("220 " + conn.vhost + " SMTP " + this.getClass().getName());
  80             Address from = null;
  81             Vector to = new Vector();
  82             boolean ehlo = false;
  83             String remotehost = null;
  84             for(String command = conn.readln(); ; command = conn.readln()) try {
  85                 if (command == null) return;
  86                 Log.warn("**"+conn.getRemoteAddress()+"**", command);
  87                 String c = command.toUpperCase();
  88                 if (c.startsWith("HELO"))        {
  89                     remotehost = c.substring(5).trim();
  90                     conn.println("250 HELO " + conn.vhost);
  91                     from = null; to = new Vector();
  92                 } else if (c.startsWith("EHLO")) {
  93                     remotehost = c.substring(5).trim();
  94                     conn.println("250 "+conn.vhost+" greets " + remotehost);
  95                     ehlo = true;
  96                     from = null; to = new Vector();
  97                 } else if (c.startsWith("RSET")) { conn.println("250 reset ok");           from = null; to = new Vector();
  98                 } else if (c.startsWith("HELP")) { conn.println("214 you are beyond help.  see a trained professional.");
  99                 } else if (c.startsWith("VRFY")) { conn.println("502 VRFY not supported");
 100                 } else if (c.startsWith("EXPN")) { conn.println("502 EXPN not supported");
 101                 } else if (c.startsWith("NOOP")) { conn.println("250 OK");
 102                 } else if (c.startsWith("QUIT")) { conn.println("221 " + conn.vhost + " closing connection"); return;
 103                 } else if (c.startsWith("MAIL FROM:")) {
 104                     command = command.substring(10).trim();
 105                     from = command.equals("<>") ? null : new Address(command);
 106                     conn.println("250 " + from + " is syntactically correct");
 107                 } else if (c.startsWith("RCPT TO:")) {
 108                     // some clients are broken and put RCPT first; we will tolerate this
 109                     command = command.substring(8).trim();
 110                     if(command.indexOf(' ') != -1) command = command.substring(0, command.indexOf(' '));
 111                     Address addr = new Address(command);
 112                     /*
 113                     Log.warn("**"+conn.getRemoteAddress()+"**",
 114                              "addr.isLocal(): " + addr.isLocal() + "\n" +
 115                              "conn.getRemoteAddress().isLoopbackAddress(): " + conn.getRemoteAddress().isLoopbackAddress() + "\n" +
 116                              "johnw: " + (from!=null&&from.toString().indexOf("johnw")!=-1) + "\n"
 117                              );
 118                     */
 119                     if (addr.isLocal()) {
 120                         // FEATURE: should check the address further and give 550 if undeliverable
 121                         conn.println("250 " + addr + " is on this machine; I will deliver it");
 122                         to.addElement(addr);
 123                     } else if (conn.getRemoteAddress().isLoopbackAddress() || (from!=null&&from.toString().indexOf("johnw")!=-1)) {
 124                         conn.println("250 you are connected locally, so I will let you send");
 125                         to.addElement(addr);
 126                     } else {
 127                         conn.println("551 sorry, " + addr + " is not on this machine");
 128                     }
 129                 } else if (c.startsWith("DATA")) {
 130                     //if (from == null) { conn.println("503 MAIL FROM command must precede DATA"); continue; }
 131                     if (to == null || to.size()==0) { conn.println("503 RCPT TO command must precede DATA"); continue; }
 132                     if (!graylist.isWhitelisted(conn.getRemoteAddress()) && !conn.getRemoteAddress().isLoopbackAddress()) {
 133                         long when = graylist.getGrayListTimestamp(conn.getRemoteAddress(), from+"", to+"");
 134                         if (when == 0 || System.currentTimeMillis() - when > GRAYLIST_MAXWAIT) {
 135                             graylist.setGrayListTimestamp(conn.getRemoteAddress(), from+"", to+"",  System.currentTimeMillis());
 136                             conn.println("451 you are graylisted; please try back in one hour to be whitelisted");
 137                             Log.warn(conn.getRemoteAddress().toString(), "451 you are graylisted; please try back in one hour to be whitelisted");
 138                             conn.flush();
 139                             continue;
 140                         } else if (System.currentTimeMillis() - when > GRAYLIST_MINWAIT) {
 141                             graylist.addWhitelist(conn.getRemoteAddress());
 142                             conn.println("354 (you have been whitelisted) Enter message, ending with \".\" on a line by itself");
 143                             Log.warn(conn.getRemoteAddress().toString(), "has been whitelisted");
 144                         } else {
 145                             conn.println("451 you are still graylisted (since "+new java.util.Date(when)+")");
 146                             conn.flush();
 147                             Log.warn(conn.getRemoteAddress().toString(), "451 you are still graylisted (since "+new java.util.Date(when)+")");
 148                             continue;
 149                         }
 150                     } else {
 151                         conn.println("354 Enter message, ending with \".\" on a line by itself");
 152                     }
 153                     conn.flush();
 154                     try {
 155                         StringBuffer buf = new StringBuffer();
 156                         buf.append("Received: from " + conn.getRemoteHostname() + " (" + remotehost + ")\r\n");
 157                         buf.append("          by "+conn.vhost+" ("+SMTP.class.getName()+") with "+(ehlo?"ESMTP":"SMTP") + "\r\n");
 158                         buf.append("          for ");
 159                         // FIXME: this is leaking BCC addrs
 160                         // for(int i=0; i<to.size(); i++) buf.append(to.elementAt(i) + " ");
 161                         buf.append("; " + dateFormat.format(new Date()) + "\r\n");
 162                         while(true) {
 163                             String s = conn.readln();
 164                             if (s == null) throw new RuntimeException("connection closed");
 165                             if (s.equals(".")) break;
 166                             if (s.startsWith(".")) s = s.substring(1);
 167                             buf.append(s + "\r\n");
 168                             if (MAX_MESSAGE_SIZE != -1 && buf.length() > MAX_MESSAGE_SIZE) {
 169                                 Log.error("**"+conn.getRemoteAddress()+"**",
 170                                           "sorry, this mail server only accepts messages of less than " +
 171                                           ByteSize.toString(MAX_MESSAGE_SIZE));
 172                                 throw new MailException.Malformed("sorry, this mail server only accepts messages of less than " +
 173                                                                   ByteSize.toString(MAX_MESSAGE_SIZE));
 174                             }
 175                         }
 176                         String body = buf.toString();
 177                         Message m = null;
 178                         for(int i=0; i<to.size(); i++) {
 179                             m = Message.newMessage(new Fountain.StringFountain(body), from, (Address)to.elementAt(i));
 180                             accept(m);
 181                         }
 182                         if (m != null) Log.info(SMTP.class, "accepted message: " + m.summary());
 183                         conn.println("250 message accepted");
 184                         conn.flush();
 185                         from = null; to = new Vector();
 186                     } catch (Reject.RejectException re) {
 187                         Log.warn(SMTP.class, "rejecting message due to: " + re.reason + "\n   " + re.m.summary());
 188                         conn.println("501 " + re.reason);
 189                     } catch (MailException.Malformed mfe) {   conn.println("501 " + mfe.toString());
 190                     } catch (MailException.MailboxFull mbf) { conn.println("452 " + mbf);
 191                     } catch (Later.LaterException le) {       conn.println("453 try again later");
 192                     } catch (IOException ioe) {
 193                         //conn.println("554 " + ioe.toString());
 194                         Log.error(this, ioe);
 195                         conn.close();
 196                         return;
 197                     }
 198                 } else                    { conn.println("500 unrecognized command"); }
 199             } catch (Message.Malformed e) { conn.println("501 " + e.toString()); }
 200         }
 201     }
 202
 203
 204     // Outgoing Mail Thread //////////////////////////////////////////////////////////////////////////////
 205
 206     public static class Outgoing extends Thread {
 207
 208         private static final HashMap deadHosts = new HashMap();
 209         public static void accept(Message m) throws IOException {
 210             if (m == null) { Log.warn(Outgoing.class, "attempted to accept(null)"); return; }
 211             String traces = m.headers.get("Received");
 212             if (traces!=null) {
 213                 int lines = 0;
 214                 for(int i=0; i<traces.length(); i++)
 215                     if (traces.charAt(i)=='\n' || traces.charAt(i)=='\r')
 216                         lines++;
 217                 if (lines > 100) { // required by rfc
 218                     Log.warn(SMTP.Outgoing.class, "Message with " + lines + " trace hops; dropping\n" + m.summary());
 219                     return;
 220                 }
 221             }
 222             synchronized(Outgoing.class) {
 223                 spool.add(m);
 224                 Outgoing.class.notifyAll();
 225             }
 226         }
 227
 228         public static boolean attempt(Message m) throws IOException { return attempt(m, false); }
 229         public static boolean attempt(Message m, boolean noBounces) throws IOException {
 230             if (m.envelopeTo == null) {
 231                 Log.warn(SMTP.Outgoing.class, "aieeee, null envelopeTo: " + m.summary());
 232                 return false;
 233             }
 234             InetAddress[] mx = getMailExchangerIPs(m.envelopeTo.host);
 235             if (mx.length == 0) {
 236                 if (!noBounces) {
 237                     accept(m.bounce("could not resolve " + m.envelopeTo.host));
 238                     return true;
 239                 } else {
 240                     Log.warn(SMTP.Outgoing.class, "could not resolve " + m.envelopeTo.host);
 241                     return false;
 242                 }
 243             }
 244             if (new Date().getTime() - m.arrival.getTime() > 1000 * 60 * 60 * 24 * 5) {
 245                 if (!noBounces) {
 246                     accept(m.bounce("could not send for 5 days"));
 247                     return true;
 248                 } else {
 249                     Log.warn(SMTP.Outgoing.class, "could not send for 5 days: " + m.summary());
 250                     return false;
 251                 }
 252             }
 253             for(int i=0; i<mx.length; i++) {
 254                 //if (deadHosts.contains(mx[i])) continue;
 255                 if (attempt(m, mx[i])) { return true; }
 256             }
 257             return false;
 258         }
 259
 260         private static void check(String s, Connection conn) {
 261             if (s==null) return;
 262             while (s.length() > 3 && s.charAt(3) == '-') s = conn.readln();
 263             if (s.startsWith("4")||s.startsWith("5")) throw new SMTPException(s);
 264         }
 265         private static boolean attempt(final Message m, final InetAddress mx) {
 266             boolean accepted = false;
 267             Connection conn = null;
 268             try {
 269                 Log.note("connecting to " + mx + "...");
 270                 conn = new Connection(new Socket(mx, 25), InetAddress.getLocalHost().getHostName());
 271                 conn.setNewline("\r\n");
 272                 conn.setTimeout(60 * 1000);
 273                 Log.note("    connected");
 274                 check(conn.readln(), conn);  // banner
 275                 try {
 276                     conn.println("EHLO " + conn.vhost);
 277                     check(conn.readln(), conn);
 278                 } catch (SMTPException smtpe) {
 279                     conn.println("HELO " + conn.vhost);
 280                     check(conn.readln(), conn);
 281                 }
 282                 if (m.envelopeFrom==null) {
 283                     Log.warn("", "MAIL FROM:<>");
 284                     conn.println("MAIL FROM:<>");  check(conn.readln(), conn);
 285                 } else {
 286                     Log.warn("", "MAIL FROM:<" + m.envelopeFrom.toString()+">");
 287                     conn.println("MAIL FROM:<" + m.envelopeFrom.toString()+">");  check(conn.readln(), conn);
 288                 }
 289                 conn.println("RCPT TO:<"   + m.envelopeTo.toString()+">");      check(conn.readln(), conn);
 290                 conn.println("DATA");                          check(conn.readln(), conn);
 291                 Headers head = m.headers;
 292                 head = head.remove("return-path");
 293                 head = head.remove("bcc");
 294                 Stream stream = head.getStream();
 295                 for(String s = stream.readln(); s!=null; s=stream.readln()) {
 296                     if (s.startsWith(".")) conn.print(".");
 297                     conn.println(s);
 298                 }
 299                 conn.println("");
 300                 stream = m.getBody().getStream();
 301                 for(String s = stream.readln(); s!=null; s=stream.readln()) {
 302                     if (s.startsWith(".")) conn.print(".");
 303                     conn.println(s);
 304                 }
 305                 conn.println(".");
 306                 String resp = conn.readln();
 307                 if (resp == null)
 308                     throw new SMTPException("server " + mx + " closed connection without accepting message");
 309                 check(resp, conn);
 310                 Log.warn(SMTP.Outgoing.class, "success: " + mx + " accepted " + m.summary() + "\n["+resp+"]");
 311                 accepted = true;
 312                 conn.close();
 313             } catch (SMTPException e) {
 314                 if (accepted) return true;
 315                 Log.warn(SMTP.Outgoing.class, "    unable to send; error=" + e);
 316                 Log.warn(SMTP.Outgoing.class, "      message: " + m.summary());
 317                 Log.warn(SMTP.Outgoing.class, e);
 318                 if (e.code >= 500 && e.code <= 599) {
 319                     try {
 320                         attempt(m.bounce("unable to deliver: " + e), true);
 321                     } catch (Exception ex) {
 322                         Log.error(SMTP.Outgoing.class, "exception while trying to deliver bounce; giving up completely");
 323                         Log.error(SMTP.Outgoing.class, ex);
 324                     }
 325                     return true;
 326                 }
 327                 return false;
 328             } catch (Exception e) {
 329                 if (accepted) return true;
 330                 Log.warn(SMTP.Outgoing.class, "    unable to send; error=" + e);
 331                 Log.warn(SMTP.Outgoing.class, "      message: " + m.summary());
 332                 Log.warn(SMTP.Outgoing.class, e);
 333                 if (conn != null) Log.warn(SMTP.Outgoing.class, conn.dumpLog());
 334                 return false;
 335             } finally {
 336                 if (conn != null) conn.close();
 337             }
 338             return accepted;
 339         }
 340
 341         private static HashSet<Outgoing> threads = new HashSet<Outgoing>();
 342         private static int serials = 1;
 343         private int serial = serials++;
 344         private Mailbox.Iterator it;
 345
 346         public Outgoing() {
 347             synchronized(Outgoing.class) {
 348                 threads.add(this);
 349             }
 350         }
 351
 352         public void wake() {
 353             int count = spool.count(Query.all());
 354             Log.info(SMTP.Outgoing.class, "outgoing thread #"+serial+" woke up; " + count + " messages to send");
 355             try {
 356                 while(true) {
 357                     boolean good = false;
 358                     synchronized(Outgoing.class) {
 359                         it = spool.iterator();
 360                         OUTER: for(; it.next(); ) {
 361                             for(Outgoing o : threads)
 362                                 if (o!=this && o.it != null && o.it.uid()==it.uid())
 363                                     continue OUTER;
 364                             good = true;
 365                             break;
 366                         }
 367                     }
 368                     if (!good) break;
 369                     try {
 370                         if (attempt(it.cur())) it.delete();
 371                     } catch (Exception e) {
 372                         Log.error(SMTP.Outgoing.class, e);
 373                     }
 374                     Log.info(this, "sleeping for 3s...");
 375                     Thread.sleep(3000);
 376                 }
 377             } catch (Exception e) {
 378                 //if (e instanceof InterruptedException) throw e;
 379                 Log.error(SMTP.Outgoing.class, e);
 380             }
 381             Log.info(SMTP.Outgoing.class, "outgoing thread #"+serial+" going back to sleep");
 382             it = null;
 383         }
 384
 385         public void run() {
 386             try {
 387                 while(true) {
 388                     Log.setThreadAnnotation("[outgoing #"+serial+"] ");
 389                     wake();
 390                     Thread.sleep(1000);
 391                     synchronized(Outgoing.class) {
 392                         Outgoing.class.wait(5 * 60 * 1000);
 393                     }
 394                 }
 395             } catch (InterruptedException e) { Log.warn(this, e); }
 396         }
 397     }
 398
 399     public static InetAddress[] getMailExchangerIPs(String hostName) {
 400         InetAddress[] ret;
 401         try {
 402             Hashtable env = new Hashtable();
 403             env.put("java.naming.factory.initial", "com.sun.jndi.dns.DnsContextFactory");
 404             DirContext ictx = new InitialDirContext(env);
 405             Attributes attrs = ictx.getAttributes(hostName, new String[] { "MX" });
 406             Attribute attr = attrs.get("MX");
 407             if (attr == null) {
 408                 ret = new InetAddress[1];
 409                 try {
 410                     ret[0] = InetAddress.getByName(hostName);
 411                     if (ret[0].equals(IP.getIP(127,0,0,1)) || ret[0].isLoopbackAddress()) throw new UnknownHostException();
 412                     return ret;
 413                 } catch (UnknownHostException uhe) {
 414                     Log.warn(SMTP.class, "no MX hosts or A record for " + hostName);
 415                     return new InetAddress[0];
 416                 }
 417             } else {
 418                 ret = new InetAddress[attr.size()];
 419                 NamingEnumeration ne = attr.getAll();
 420                 for(int i=0; ne.hasMore();) {
 421                     String mx = (String)ne.next();
 422                     // FIXME we should be sorting here
 423                     mx = mx.substring(mx.indexOf(" ") + 1);
 424                     if (mx.charAt(mx.length() - 1) == '.') mx = mx.substring(0, mx.length() - 1);
 425                     InetAddress ia = InetAddress.getByName(mx);
 426                     if (ia.equals(IP.getIP(127,0,0,1)) || ia.isLoopbackAddress()) continue;
 427                     ret[i++] = ia;
 428                 }
 429             }
 430         } catch (Exception e) {
 431             Log.warn(SMTP.class, "couldn't find MX host for " + hostName + " due to");
 432             Log.warn(SMTP.class, e);
 433             return new InetAddress[0];
 434         }
 435         return ret;
 436     }
 437 }