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