src/org/cacert/gigi/util/EmailChecker.java

   1 package org.cacert.gigi.util;
   2
   3 import java.io.BufferedReader;
   4 import java.io.IOException;
   5 import java.io.InputStreamReader;
   6 import java.io.PrintWriter;
   7 import java.net.Socket;
   8 import java.sql.PreparedStatement;
   9 import java.sql.SQLException;
  10 import java.util.LinkedList;
  11 import java.util.regex.Pattern;
  12
  13 import org.cacert.gigi.database.DatabaseConnection;
  14
  15 public class EmailChecker {
  16         public static final String OK = "OK";
  17         public static final String FAIL = "FAIL";
  18         private static final Pattern MAIL = Pattern
  19                         .compile("^([a-zA-Z0-9])+([a-zA-Z0-9\\+\\._-])*@([a-zA-Z0-9_-])+([a-zA-Z0-9\\._-]+)+$");
  20         private EmailChecker() {
  21         }
  22         public static String checkEmailServer(int forUid, String address)
  23                         throws IOException {
  24                 if (MAIL.matcher(address).matches()) {
  25                         String[] parts = address.split("@", 2);
  26                         String domain = parts[1];
  27
  28                         LinkedList<String> mxhosts = getMxHosts(domain);
  29
  30                         for (String host : mxhosts) {
  31                                 try (Socket s = new Socket(host, 25);
  32                                                 BufferedReader br = new BufferedReader(
  33                                                                 new InputStreamReader(s.getInputStream()));
  34                                                 PrintWriter pw = new PrintWriter(s.getOutputStream())) {
  35                                         String line;
  36                                         while ((line = br.readLine()).startsWith("220-")) {
  37                                         }
  38
  39                                         if (!line.startsWith("220")) {
  40                                                 continue;
  41                                         }
  42
  43                                         pw.print("HELO www.cacert.org\r\n");
  44                                         pw.flush();
  45
  46                                         while ((line = br.readLine()).startsWith("220")) {
  47                                         }
  48
  49                                         if (!line.startsWith("250")) {
  50                                                 continue;
  51                                         }
  52                                         pw.print("MAIL FROM: <returns@cacert.org>\r\n");
  53                                         pw.flush();
  54
  55                                         line = br.readLine();
  56
  57                                         if (!line.startsWith("250")) {
  58                                                 continue;
  59                                         }
  60                                         pw.print("RCPT TO: <" + address + ">\r\n");
  61                                         pw.flush();
  62
  63                                         line = br.readLine();
  64                                         pw.print("QUIT\r\n");
  65                                         pw.flush();
  66
  67                                         try {
  68                                                 PreparedStatement statmt = DatabaseConnection
  69                                                                 .getInstance()
  70                                                                 .prepare(
  71                                                                                 "insert into `pinglog` set `when`=NOW(), `email`=?, `result`=?, `uid`=?");
  72                                                 statmt.setString(1, address);
  73                                                 statmt.setString(2, line);
  74                                                 statmt.setInt(3, forUid);
  75                                                 statmt.execute();
  76                                         } catch (SQLException e) {
  77                                                 e.printStackTrace();
  78                                         }
  79
  80                                         if (!line.startsWith("250")) {
  81                                                 return line;
  82                                         } else {
  83                                                 return OK;
  84                                         }
  85                                 }
  86
  87                         }
  88                 }
  89                 try {
  90                         PreparedStatement statmt = DatabaseConnection
  91                                         .getInstance()
  92                                         .prepare(
  93                                                         "insert into `pinglog` set `when`=NOW(), `email`=?, `result`=?, `uid`=?");
  94                         statmt.setString(1, address);
  95                         statmt.setString(2,
  96                                         "Failed to make a connection to the mail server");
  97                         statmt.setInt(3, forUid);
  98                         statmt.execute();
  99                 } catch (SQLException e) {
 100                         e.printStackTrace();
 101                 }
 102                 return FAIL;
 103         }
 104         private static LinkedList<String> getMxHosts(String domain)
 105                         throws IOException {
 106                 LinkedList<String> mxhosts = new LinkedList<String>();
 107                 Process dig = Runtime.getRuntime().exec(
 108                                 new String[]{"dig", "+short", "MX", domain});
 109                 try (BufferedReader br = new BufferedReader(new InputStreamReader(
 110                                 dig.getInputStream()))) {
 111                         String line;
 112                         while ((line = br.readLine()) != null) {
 113                                 String[] mxparts = line.split(" ", 2);
 114                                 if (mxparts.length != 2) {
 115                                         continue;
 116                                 }
 117                                 mxhosts.add(mxparts[1].substring(0, mxparts[1].length() - 1));
 118                         }
 119                 }
 120                 return mxhosts;
 121         }
 122
 123 }