src/org/ibex/mail/SMTP.java

   1 // Copyright 2000-2005 the Contributors, as shown in the revision logs.
   2 // Licensed under the Apache Public Source License 2.0 ("the License").
   3 // You may not use this file except in compliance with the License.
   4
   5 package org.ibex.mail;
   6 import org.ibex.mail.target.*;
   7 import org.ibex.util.*;
   8 import org.ibex.net.*;
   9 import org.ibex.io.*;
  10 import java.net.*;
  11 import java.io.*;
  12 import java.util.*;
  13 import java.text.*;
  14 import javax.naming.*;
  15 import javax.naming.directory.*;
  16
  17 // RFC's implemented
  18 // RFC2554: SMTP Service Extension for Authentication
  19 //     - did not implement section 5, though
  20 // RFC4616: SASL PLAIN
  21
  22 // Note: we can't actually use status codes for feedback if we accept
  23 // multiple destination addresses...  a failure on one and success on
  24 // the other...
  25
  26 // FIXME: logging: current logging sucks
  27 // FIXME: loop prevention
  28 // FIXME: probably need some throttling on outbound mail
  29
  30 // FEATURE: public static boolean validate(Address a)
  31 // FEATURE: rate-limiting
  32
  33 // FEATURE: infer messageid, date, if not present (?)
  34 // FEATURE: exponential backoff on retry time?
  35 // FEATURE: RFC2822, section 4.5.1: special "postmaster" address
  36 // FEATURE: RFC2822, section 4.5.4.1: retry strategies
  37 // FEATURE: RFC2822, section 5, multiple MX records, preferences, ordering
  38 // FEATURE: RFC2822, end of 4.1.2: backslashes in headers
  39 public class SMTP {
  40
  41     public static final SimpleDateFormat dateFormat = new SimpleDateFormat("EEE, d MMM yyyy HH:mm:ss Z");
  42     public static final int numOutgoingThreads = 5;
  43
  44     public static final int GRAYLIST_MINWAIT =  1000 * 60 * 60;           // one hour
  45     public static final int GRAYLIST_MAXWAIT =  1000 * 60 * 60 * 24 * 5;  // five days
  46
  47     public static final Graylist graylist =
  48         new Graylist(Mailbox.STORAGE_ROOT+"/db/graylist.sqlite");
  49
  50     public static final Whitelist whitelist =
  51         new Whitelist(Mailbox.STORAGE_ROOT+"/db/whitelist.sqlite");
  52
  53     public static final int MAX_MESSAGE_SIZE =
  54         Integer.parseInt(System.getProperty("org.ibex.mail.smtp.maxMessageSize", "-1"));
  55
  56     private static final Mailbox spool =
  57         FileBasedMailbox.getFileBasedMailbox(Mailbox.STORAGE_ROOT,false).slash("spool",true).slash("smtp",true);
  58
  59     static {
  60         for(int i=0; i<numOutgoingThreads; i++)
  61             new Outgoing().start();
  62     }
  63
  64     public static void enqueue(Message m) throws IOException {
  65         if (!m.envelopeTo.isLocal()) Outgoing.enqueue(m);
  66         else                         Target.root.accept(m);
  67     }
  68
  69     public static class SMTPException extends MailException {
  70         int code;
  71         String message;
  72         public SMTPException(String s) {
  73             try {
  74                 code = Integer.parseInt(s.substring(0, s.indexOf(' ')));
  75                 message = s.substring(s.indexOf(' ')+1);
  76             } catch (NumberFormatException nfe) {
  77                 code = -1;
  78                 message = s;
  79             }
  80         }
  81         public String toString() { return "SMTP " + code + ": " + message; }
  82         public String getMessage() { return toString(); }
  83     }
  84
  85     // Server //////////////////////////////////////////////////////////////////////////////
  86
  87     public static class Server {
  88         public void handleRequest(Connection conn) throws IOException {
  89             conn.setTimeout(5 * 60 * 1000);
  90             conn.setNewline("\r\n");
  91             conn.println("220 " + conn.vhost + " ESMTP " + this.getClass().getName());
  92             Address from = null;
  93             Vector to = new Vector();
  94             boolean ehlo = false;
  95             String remotehost = null;
  96             for(String command = conn.readln(); ; command = conn.readln()) try {
  97                 if (command == null) return;
  98                 //Log.warn("**"+conn.getRemoteAddress()+"**", command);
  99                 String c = command.toUpperCase();
 100                 if (c.startsWith("HELO"))        {
 101                     remotehost = c.substring(5).trim();
 102                     conn.println("250 HELO " + conn.vhost);
 103                     from = null; to = new Vector();
 104                 } else if (c.startsWith("EHLO")) {
 105                     remotehost = c.substring(5).trim();
 106                     conn.println("250 "+conn.vhost+" greets " + remotehost);
 107                     ehlo = true;
 108                     from = null; to = new Vector();
 109                 } else if (c.startsWith("RSET")) { conn.println("250 reset ok");           from = null; to = new Vector();
 110                 } else if (c.startsWith("HELP")) { conn.println("214 you are beyond help.  see a trained professional.");
 111                 } else if (c.startsWith("VRFY")) { conn.println("502 VRFY not supported");
 112                 } else if (c.startsWith("EXPN")) { conn.println("502 EXPN not supported");
 113                 } else if (c.startsWith("NOOP")) { conn.println("250 OK");
 114                 } else if (c.startsWith("QUIT")) { conn.println("221 " + conn.vhost + " closing connection"); return;
 115                 } else if (c.startsWith("MAIL FROM:")) {
 116                     command = command.substring(10).trim();
 117                     from = command.equals("<>") ? null : new Address(command);
 118                     conn.println("250 " + from + " is syntactically correct");
 119                 } else if (c.startsWith("RCPT TO:")) {
 120                     // some clients are broken and put RCPT first; we will tolerate this
 121                     command = command.substring(8).trim();
 122                     if(command.indexOf(' ') != -1) command = command.substring(0, command.indexOf(' '));
 123                     Address addr = new Address(command);
 124                     /*
 125                     Log.warn("**"+conn.getRemoteAddress()+"**",
 126                              "addr.isLocal(): " + addr.isLocal() + "\n" +
 127                              "conn.getRemoteAddress().isLoopbackAddress(): " + conn.getRemoteAddress().isLoopbackAddress() + "\n" +
 128                              "johnw: " + (from!=null&&from.toString().indexOf("johnw")!=-1) + "\n"
 129                              );
 130                     */
 131                     if (addr.isLocal()) {
 132                         // FEATURE: should check the address further and give 550 if undeliverable
 133                         conn.println("250 " + addr + " is on this machine; I will deliver it");
 134                         to.addElement(addr);
 135                     } else if (conn.getRemoteAddress().isLoopbackAddress() || (from!=null&&from.toString().indexOf("johnw")!=-1)) {
 136                         conn.println("250 you are connected locally, so I will let you send");
 137                         to.addElement(addr);
 138                     } else {
 139                         conn.println("551 sorry, " + addr + " is not on this machine");
 140                     }
 141                     conn.flush();
 142                 } else if (c.startsWith("DATA")) {
 143                     //if (from == null) { conn.println("503 MAIL FROM command must precede DATA"); continue; }
 144                     if (to == null || to.size()==0) { conn.println("503 RCPT TO command must precede DATA"); continue; }
 145                     if (!graylist.isWhitelisted(conn.getRemoteAddress()) && !conn.getRemoteAddress().isLoopbackAddress()) {
 146                         long when = graylist.getGrayListTimestamp(conn.getRemoteAddress(), from+"", to+"");
 147                         if (when == 0 || System.currentTimeMillis() - when > GRAYLIST_MAXWAIT) {
 148                             graylist.setGrayListTimestamp(conn.getRemoteAddress(), from+"", to+"",  System.currentTimeMillis());
 149                             conn.println("451 you are graylisted; please try back in one hour to be whitelisted");
 150                             Log.warn(conn.getRemoteAddress().toString(), "451 you are graylisted; please try back in one hour to be whitelisted");
 151                             conn.flush();
 152                             continue;
 153                         } else if (System.currentTimeMillis() - when > GRAYLIST_MINWAIT) {
 154                             graylist.addWhitelist(conn.getRemoteAddress());
 155                             conn.println("354 (you have been whitelisted) Enter message, ending with \".\" on a line by itself");
 156                             Log.warn(conn.getRemoteAddress().toString(), "has been whitelisted");
 157                         } else {
 158                             conn.println("451 you are still graylisted (since "+new java.util.Date(when)+")");
 159                             conn.flush();
 160                             Log.warn(conn.getRemoteAddress().toString(), "451 you are still graylisted (since "+new java.util.Date(when)+")");
 161                             continue;
 162                         }
 163                     } else {
 164                         conn.println("354 Enter message, ending with \".\" on a line by itself");
 165                     }
 166                     conn.flush();
 167                     try {
 168                         StringBuffer buf = new StringBuffer();
 169                         buf.append("Received: from " + conn.getRemoteHostname() + " (" + remotehost + ")\r\n");
 170                         buf.append("          by "+conn.vhost+" ("+SMTP.class.getName()+") with "+(ehlo?"ESMTP":"SMTP") + "\r\n");
 171                         buf.append("          for ");
 172                         // FIXME: this is leaking BCC addrs
 173                         // for(int i=0; i<to.size(); i++) buf.append(to.elementAt(i) + " ");
 174                         buf.append("; " + dateFormat.format(new Date()) + "\r\n");
 175                         while(true) {
 176                             String s = conn.readln();
 177                             if (s == null) throw new RuntimeException("connection closed");
 178                             if (s.equals(".")) break;
 179                             if (s.startsWith(".")) s = s.substring(1);
 180                             buf.append(s + "\r\n");
 181                             if (MAX_MESSAGE_SIZE != -1 && buf.length() > MAX_MESSAGE_SIZE) {
 182                                 Log.error("**"+conn.getRemoteAddress()+"**",
 183                                           "sorry, this mail server only accepts messages of less than " +
 184                                           ByteSize.toString(MAX_MESSAGE_SIZE));
 185                                 throw new MailException.Malformed("sorry, this mail server only accepts messages of less than " +
 186                                                                   ByteSize.toString(MAX_MESSAGE_SIZE));
 187                             }
 188                         }
 189                         String body = buf.toString();
 190                         Message m = null;
 191                         for(int i=0; i<to.size(); i++) {
 192                             m = Message.newMessage(new Fountain.StringFountain(body), from, (Address)to.elementAt(i));
 193                             accept(m);
 194                         }
 195                         if (m != null) Log.info(SMTP.class, "accepted message: " + m.summary());
 196                         conn.println("250 message accepted");
 197                         conn.flush();
 198                         from = null; to = new Vector();
 199                     } catch (MailException.Malformed mfe) {    conn.println("501 " + mfe.toString());
 200                     } catch (MailException.MailboxFull mbf) {  conn.println("452 " + mbf);
 201                     } catch (Script.Later.LaterException le) { conn.println("453 try again later");
 202                     } catch (Script.Reject.RejectException re) {
 203                         Log.warn(SMTP.class, "rejecting message due to: " + re.reason + "\n   " + re.m.summary());
 204                         conn.println("501 " + re.reason);
 205                     }
 206                 } else                    { conn.println("500 unrecognized command"); }
 207             } catch (Message.Malformed e) { conn.println("501 " + e.toString()); }
 208         }
 209     }
 210
 211
 212     // Outgoing Mail Thread //////////////////////////////////////////////////////////////////////////////
 213
 214     public static class Outgoing extends Thread {
 215
 216         private static final HashMap deadHosts = new HashMap();
 217         public static void accept(Message m) throws IOException {
 218             if (m == null) { Log.warn(Outgoing.class, "attempted to accept(null)"); return; }
 219             String traces = m.headers.get("Received");
 220             if (traces!=null) {
 221                 int lines = 0;
 222                 for(int i=0; i<traces.length(); i++)
 223                     if (traces.charAt(i)=='\n' || traces.charAt(i)=='\r')
 224                         lines++;
 225                 if (lines > 100) { // required by rfc
 226                     Log.warn(SMTP.Outgoing.class, "Message with " + lines + " trace hops; dropping\n" + m.summary());
 227                     return;
 228                 }
 229             }
 230             synchronized(Outgoing.class) {
 231                 spool.insert(m, Mailbox.Flag.defaultFlags);
 232                 Outgoing.class.notifyAll();
 233             }
 234         }
 235
 236         public static boolean attempt(Message m) throws IOException { return attempt(m, false); }
 237         public static boolean attempt(Message m, boolean noBounces) throws IOException {
 238             if (m.envelopeTo == null) {
 239                 Log.warn(SMTP.Outgoing.class, "aieeee, null envelopeTo: " + m.summary());
 240                 return false;
 241             }
 242             InetAddress[] mx = getMailExchangerIPs(m.envelopeTo.host);
 243             if (mx.length == 0) {
 244                 if (!noBounces) {
 245                     accept(m.bounce("could not resolve " + m.envelopeTo.host));
 246                     return true;
 247                 } else {
 248                     Log.warn(SMTP.Outgoing.class, "could not resolve " + m.envelopeTo.host);
 249                     return false;
 250                 }
 251             }
 252             if (new Date().getTime() - m.arrival.getTime() > 1000 * 60 * 60 * 24 * 5) {
 253                 if (!noBounces) {
 254                     accept(m.bounce("could not send for 5 days"));
 255                     return true;
 256                 } else {
 257                     Log.warn(SMTP.Outgoing.class, "could not send for 5 days: " + m.summary());
 258                     return false;
 259                 }
 260             }
 261             for(int i=0; i<mx.length; i++) {
 262                 //if (deadHosts.contains(mx[i])) continue;
 263                 if (attempt(m, mx[i])) { return true; }
 264             }
 265             return false;
 266         }
 267
 268         private static void check(String s, Connection conn) {
 269             if (s==null) return;
 270             while (s.length() > 3 && s.charAt(3) == '-') s = conn.readln();
 271             if (s.startsWith("4")||s.startsWith("5")) throw new SMTPException(s);
 272         }
 273         private static boolean attempt(final Message m, final InetAddress mx) {
 274             boolean accepted = false;
 275             Connection conn = null;
 276             try {
 277                 Log.note("connecting to " + mx + "...");
 278                 conn = new Connection(new Socket(mx, 25), InetAddress.getLocalHost().getHostName());
 279                 conn.setNewline("\r\n");
 280                 conn.setTimeout(60 * 1000);
 281                 Log.note("    connected");
 282                 check(conn.readln(), conn);  // banner
 283                 try {
 284                     conn.println("EHLO " + conn.vhost);
 285                     check(conn.readln(), conn);
 286                 } catch (SMTPException smtpe) {
 287                     conn.println("HELO " + conn.vhost);
 288                     check(conn.readln(), conn);
 289                 }
 290                 if (m.envelopeFrom==null) {
 291                     Log.warn("", "MAIL FROM:<>");
 292                     conn.println("MAIL FROM:<>");  check(conn.readln(), conn);
 293                 } else {
 294                     Log.warn("", "MAIL FROM:<" + m.envelopeFrom.toString()+">");
 295                     conn.println("MAIL FROM:<" + m.envelopeFrom.toString()+">");  check(conn.readln(), conn);
 296                 }
 297                 conn.println("RCPT TO:<"   + m.envelopeTo.toString()+">");      check(conn.readln(), conn);
 298                 conn.println("DATA");                          check(conn.readln(), conn);
 299                 Headers head = m.headers;
 300                 head = head.remove("return-path");
 301                 head = head.remove("bcc");
 302                 Stream stream = head.getStream();
 303                 for(String s = stream.readln(); s!=null; s=stream.readln()) {
 304                     if (s.startsWith(".")) conn.print(".");
 305                     conn.println(s);
 306                 }
 307                 conn.println("");
 308                 stream = m.getBody().getStream();
 309                 for(String s = stream.readln(); s!=null; s=stream.readln()) {
 310                     if (s.startsWith(".")) conn.print(".");
 311                     conn.println(s);
 312                 }
 313                 conn.println(".");
 314                 String resp = conn.readln();
 315                 if (resp == null)
 316                     throw new SMTPException("server " + mx + " closed connection without accepting message");
 317                 check(resp, conn);
 318                 Log.warn(SMTP.Outgoing.class, "success: " + mx + " accepted " + m.summary() + "\n["+resp+"]");
 319                 accepted = true;
 320                 conn.close();
 321             } catch (SMTPException e) {
 322                 if (accepted) return true;
 323                 Log.warn(SMTP.Outgoing.class, "    unable to send; error=" + e);
 324                 Log.warn(SMTP.Outgoing.class, "      message: " + m.summary());
 325                 Log.warn(SMTP.Outgoing.class, e);
 326                 if (e.code >= 500 && e.code <= 599) {
 327                     try {
 328                         attempt(m.bounce("unable to deliver: " + e), true);
 329                     } catch (Exception ex) {
 330                         Log.error(SMTP.Outgoing.class, "exception while trying to deliver bounce; giving up completely");
 331                         Log.error(SMTP.Outgoing.class, ex);
 332                     }
 333                     return true;
 334                 }
 335                 return false;
 336             } catch (Exception e) {
 337                 if (accepted) return true;
 338                 Log.warn(SMTP.Outgoing.class, "    unable to send; error=" + e);
 339                 Log.warn(SMTP.Outgoing.class, "      message: " + m.summary());
 340                 Log.warn(SMTP.Outgoing.class, e);
 341                 if (conn != null) Log.warn(SMTP.Outgoing.class, conn.dumpLog());
 342                 return false;
 343             } finally {
 344                 if (conn != null) conn.close();
 345             }
 346             return accepted;
 347         }
 348
 349         private static HashSet<Outgoing> threads = new HashSet<Outgoing>();
 350         private static int serials = 1;
 351         private int serial = serials++;
 352         private Mailbox.Iterator it;
 353
 354         public Outgoing() {
 355             synchronized(Outgoing.class) {
 356                 threads.add(this);
 357             }
 358         }
 359
 360         public void wake() {
 361             int count = spool.count(Query.all());
 362             Log.info(SMTP.Outgoing.class, "outgoing thread #"+serial+" woke up; " + count + " messages to send");
 363             try {
 364                 while(true) {
 365                     boolean good = false;
 366                     synchronized(Outgoing.class) {
 367                         it = spool.iterator();
 368                         OUTER: for(; it.next(); ) {
 369                             for(Outgoing o : threads)
 370                                 if (o!=this && o.it != null && o.it.uid()==it.uid())
 371                                     continue OUTER;
 372                             good = true;
 373                             break;
 374                         }
 375                     }
 376                     if (!good) break;
 377                     try {
 378                         if (attempt(it.cur())) it.delete();
 379                     } catch (Exception e) {
 380                         Log.error(SMTP.Outgoing.class, e);
 381                     }
 382                     Log.info(this, "sleeping for 3s...");
 383                     Thread.sleep(3000);
 384                 }
 385             } catch (Exception e) {
 386                 //if (e instanceof InterruptedException) throw e;
 387                 Log.error(SMTP.Outgoing.class, e);
 388             }
 389             Log.info(SMTP.Outgoing.class, "outgoing thread #"+serial+" going back to sleep");
 390             it = null;
 391         }
 392
 393         public void run() {
 394             try {
 395                 while(true) {
 396                     Log.setThreadAnnotation("[outgoing #"+serial+"] ");
 397                     wake();
 398                     Thread.sleep(1000);
 399                     synchronized(Outgoing.class) {
 400                         Outgoing.class.wait(5 * 60 * 1000);
 401                     }
 402                 }
 403             } catch (InterruptedException e) { Log.warn(this, e); }
 404         }
 405     }
 406
 407     public static InetAddress[] getMailExchangerIPs(String hostName) {
 408         InetAddress[] ret;
 409         try {
 410             Hashtable env = new Hashtable();
 411             env.put("java.naming.factory.initial", "com.sun.jndi.dns.DnsContextFactory");
 412             DirContext ictx = new InitialDirContext(env);
 413             Attributes attrs = ictx.getAttributes(hostName, new String[] { "MX" });
 414             Attribute attr = attrs.get("MX");
 415             if (attr == null) {
 416                 ret = new InetAddress[1];
 417                 try {
 418                     ret[0] = InetAddress.getByName(hostName);
 419                     if (ret[0].equals(IP.getIP(127,0,0,1)) || ret[0].isLoopbackAddress()) throw new UnknownHostException();
 420                     return ret;
 421                 } catch (UnknownHostException uhe) {
 422                     Log.warn(SMTP.class, "no MX hosts or A record for " + hostName);
 423                     return new InetAddress[0];
 424                 }
 425             } else {
 426                 ret = new InetAddress[attr.size()];
 427                 NamingEnumeration ne = attr.getAll();
 428                 for(int i=0; ne.hasMore();) {
 429                     String mx = (String)ne.next();
 430                     // FIXME we should be sorting here
 431                     mx = mx.substring(mx.indexOf(" ") + 1);
 432                     if (mx.charAt(mx.length() - 1) == '.') mx = mx.substring(0, mx.length() - 1);
 433                     InetAddress ia = InetAddress.getByName(mx);
 434                     if (ia.equals(IP.getIP(127,0,0,1)) || ia.isLoopbackAddress()) continue;
 435                     ret[i++] = ia;
 436                 }
 437             }
 438         } catch (Exception e) {
 439             Log.warn(SMTP.class, "couldn't find MX host for " + hostName + " due to");
 440             Log.warn(SMTP.class, e);
 441             return new InetAddress[0];
 442         }
 443         return ret;
 444     }
 445 }