Simplification of DNS requests.

Originally introduced for FS#92, but now extended with retrieval for XEP-0368 (http://xmpp.org/extensions/xep-0368.html)

2 files changed, 118 insertions, 254 deletions

diff --git a/src/main/java/eu/siacs/conversations/utils/DNSHelper.java b/src/main/java/eu/siacs/conversations/utils/DNSHelper.java
index 58d53216..6da9c7e8 100644
--- a/src/main/java/eu/siacs/conversations/utils/DNSHelper.java
+++ b/src/main/java/eu/siacs/conversations/utils/DNSHelper.java
@@ -7,20 +7,12 @@ import android.net.LinkProperties;
 import android.net.Network;
 import android.net.RouteInfo;
 import android.os.Build;
-import android.os.Bundle;
-import android.os.Parcelable;
-import android.util.Log;
 
 import java.io.IOException;
 import java.net.InetAddress;
-import java.net.SocketTimeoutException;
 import java.net.UnknownHostException;
 import java.util.ArrayList;
-import java.util.Collections;
 import java.util.List;
-import java.util.Random;
-import java.util.TreeMap;
-import java.util.Map;
 import java.util.regex.Pattern;
 
 import de.measite.minidns.Client;
@@ -28,58 +20,62 @@ import de.measite.minidns.DNSMessage;
 import de.measite.minidns.Record;
 import de.measite.minidns.Record.CLASS;
 import de.measite.minidns.Record.TYPE;
-import de.measite.minidns.Record.CLASS;
 import de.measite.minidns.record.SRV;
-import de.measite.minidns.record.A;
-import de.measite.minidns.record.AAAA;
 import de.measite.minidns.record.Data;
-import de.measite.minidns.record.SRV;
 import de.measite.minidns.util.NameUtil;
 
-import java.io.IOException;
-import java.net.InetAddress;
 import java.util.TreeSet;
-import java.util.regex.Pattern;
 
 import de.thedevstack.android.logcat.Logging;
+import de.thedevstack.conversationsplus.ConversationsPlusApplication;
 import de.thedevstack.conversationsplus.dto.SrvRecord;
 
 import eu.siacs.conversations.Config;
 import eu.siacs.conversations.xmpp.jid.Jid;
 
 public class DNSHelper {
-
-	public static final Pattern PATTERN_IPV4 = Pattern.compile("\\A(25[0-5]|2[0-4]\\d|[0-1]?\\d?\\d)(\\.(25[0-5]|2[0-4]\\d|[0-1]?\\d?\\d)){3}\\z");
-	public static final Pattern PATTERN_IPV6_HEX4DECCOMPRESSED = Pattern.compile("\\A((?:[0-9A-Fa-f]{1,4}(?::[0-9A-Fa-f]{1,4})*)?) ::((?:[0-9A-Fa-f]{1,4}:)*)(25[0-5]|2[0-4]\\d|[0-1]?\\d?\\d)(\\.(25[0-5]|2[0-4]\\d|[0-1]?\\d?\\d)){3}\\z");
-	public static final Pattern PATTERN_IPV6_6HEX4DEC = Pattern.compile("\\A((?:[0-9A-Fa-f]{1,4}:){6,6})(25[0-5]|2[0-4]\\d|[0-1]?\\d?\\d)(\\.(25[0-5]|2[0-4]\\d|[0-1]?\\d?\\d)){3}\\z");
-	public static final Pattern PATTERN_IPV6_HEXCOMPRESSED = Pattern.compile("\\A((?:[0-9A-Fa-f]{1,4}(?::[0-9A-Fa-f]{1,4})*)?)::((?:[0-9A-Fa-f]{1,4}(?::[0-9A-Fa-f]{1,4})*)?)\\z");
-	public static final Pattern PATTERN_IPV6 = Pattern.compile("\\A(?:[0-9a-fA-F]{1,4}:){7}[0-9a-fA-F]{1,4}\\z");
+    private static final String CLIENT_SRV_PREFIX = "_xmpp-client._tcp.";
+    private static final String SECURE_CLIENT_SRV_PREFIX = "_xmpps-client._tcp.";
+	private static final Pattern PATTERN_IPV4 = Pattern.compile("\\A(25[0-5]|2[0-4]\\d|[0-1]?\\d?\\d)(\\.(25[0-5]|2[0-4]\\d|[0-1]?\\d?\\d)){3}\\z");
+	private static final Pattern PATTERN_IPV6_HEX4DECCOMPRESSED = Pattern.compile("\\A((?:[0-9A-Fa-f]{1,4}(?::[0-9A-Fa-f]{1,4})*)?) ::((?:[0-9A-Fa-f]{1,4}:)*)(25[0-5]|2[0-4]\\d|[0-1]?\\d?\\d)(\\.(25[0-5]|2[0-4]\\d|[0-1]?\\d?\\d)){3}\\z");
+	private static final Pattern PATTERN_IPV6_6HEX4DEC = Pattern.compile("\\A((?:[0-9A-Fa-f]{1,4}:){6,6})(25[0-5]|2[0-4]\\d|[0-1]?\\d?\\d)(\\.(25[0-5]|2[0-4]\\d|[0-1]?\\d?\\d)){3}\\z");
+	private static final Pattern PATTERN_IPV6_HEXCOMPRESSED = Pattern.compile("\\A((?:[0-9A-Fa-f]{1,4}(?::[0-9A-Fa-f]{1,4})*)?)::((?:[0-9A-Fa-f]{1,4}(?::[0-9A-Fa-f]{1,4})*)?)\\z");
+	private static final Pattern PATTERN_IPV6 = Pattern.compile("\\A(?:[0-9a-fA-F]{1,4}:){7}[0-9a-fA-F]{1,4}\\z");
 
 	protected static Client client = new Client();
 
-	public static Bundle getSRVRecord(final Jid jid, Context context) throws IOException {
-        final String host = jid.getDomainpart();
-		final List<InetAddress> servers = Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP ? getDnsServers(context) : getDnsServersPreLollipop();
-		Bundle b = new Bundle();
-		for(InetAddress server : servers) {
-			b = queryDNS(host, server);
-			if (b.containsKey("values")) {
-				return b;
-			}
-		}
-		if (!b.containsKey("values")) {
-			Log.d(Config.LOGTAG,"all dns queries failed. provide fallback A record");
-			ArrayList<Parcelable> values = new ArrayList<>();
-			values.add(createNamePortBundle(host, 5222, false));
-			b.putParcelableArrayList("values",values);
-		}
-		return b;
-	}
+    static {
+        client.setTimeout(Config.PING_TIMEOUT * 1000);
+    }
+
+    /**
+     * Queries the SRV record for the server JID.
+     * This method uses all available Domain Name Servers.
+     * @param jid the server JID
+     * @return TreeSet with SrvRecords. If no SRV record is found for JID an empty TreeSet is returned.
+     */
+    public static final TreeSet<SrvRecord> querySrvRecord(Jid jid) {
+        String host = jid.getDomainpart();
+        TreeSet<SrvRecord> result = new TreeSet<>();
+
+        final List<InetAddress> dnsServers = Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP ? getDnsServers() : getDnsServersPreLollipop();
+
+        if (dnsServers != null) {
+            for (InetAddress dnsServer : dnsServers) {
+                result = querySrvRecord(host, dnsServer);
+                if (!result.isEmpty()) {
+                    break;
+                }
+            }
+        }
+
+        return result;
+    }
 
 	@TargetApi(21)
-	private static List<InetAddress> getDnsServers(Context context) {
+	private static List<InetAddress> getDnsServers() {
 		List<InetAddress> servers = new ArrayList<>();
-		ConnectivityManager connectivityManager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
+		ConnectivityManager connectivityManager = (ConnectivityManager) ConversationsPlusApplication.getInstance().getSystemService(Context.CONNECTIVITY_SERVICE);
 		Network[] networks = connectivityManager == null ? null : connectivityManager.getAllNetworks();
 		if (networks == null) {
 			return getDnsServersPreLollipop();
@@ -95,7 +91,7 @@ public class DNSHelper {
 			}
 		}
 		if (servers.size() > 0) {
-			Log.d(Config.LOGTAG, "used lollipop variant to discover dns servers in " + networks.length + " networks");
+            Logging.d("dns", "used lollipop variant to discover dns servers in " + networks.length + " networks");
 		}
 		return servers.size() > 0 ? servers : getDnsServersPreLollipop();
 	}
@@ -123,155 +119,38 @@ public class DNSHelper {
 		return servers;
 	}
 
-	private static class TlsSrv {
-		private final SRV srv;
-		private final boolean tls;
-
-		public TlsSrv(SRV srv, boolean tls) {
-			this.srv = srv;
-			this.tls = tls;
-		}
-	}
-
-	private static void fillSrvMaps(final String qname, final InetAddress dnsServer, final Map<Integer, List<TlsSrv>> priorities, final Map<String, List<String>> ips4, final Map<String, List<String>> ips6, final boolean tls) throws IOException {
-		final DNSMessage message = client.query(qname, TYPE.SRV, CLASS.IN, dnsServer.getHostAddress());
-		for (Record[] rrset : new Record[][] { message.getAnswers(), message.getAdditionalResourceRecords() }) {
-			for (Record rr : rrset) {
-				Data d = rr.getPayload();
-				if (d instanceof SRV && NameUtil.idnEquals(qname, rr.getName())) {
-					SRV srv = (SRV) d;
-					if (!priorities.containsKey(srv.getPriority())) {
-						priorities.put(srv.getPriority(),new ArrayList<TlsSrv>());
-					}
-					priorities.get(srv.getPriority()).add(new TlsSrv(srv, tls));
-				}
-				if (d instanceof A) {
-					A a = (A) d;
-					if (!ips4.containsKey(rr.getName())) {
-						ips4.put(rr.getName(), new ArrayList<String>());
-					}
-					ips4.get(rr.getName()).add(a.toString());
-				}
-				if (d instanceof AAAA) {
-					AAAA aaaa = (AAAA) d;
-					if (!ips6.containsKey(rr.getName())) {
-						ips6.put(rr.getName(), new ArrayList<String>());
-					}
-					ips6.get(rr.getName()).add("[" + aaaa.toString() + "]");
-				}
-			}
-		}
-	}
-
-	public static Bundle queryDNS(String host, InetAddress dnsServer) {
-		Bundle bundle = new Bundle();
-		try {
-			client.setTimeout(Config.PING_TIMEOUT * 1000);
-			final String qname = "_xmpp-client._tcp." + host;
-			final String tlsQname = "_xmpps-client._tcp." + host;
-			Log.d(Config.LOGTAG, "using dns server: " + dnsServer.getHostAddress() + " to look up " + host);
-
-			final Map<Integer, List<TlsSrv>> priorities = new TreeMap<>();
-			final Map<String, List<String>> ips4 = new TreeMap<>();
-			final Map<String, List<String>> ips6 = new TreeMap<>();
-
-			fillSrvMaps(qname, dnsServer, priorities, ips4, ips6, false);
-			fillSrvMaps(tlsQname, dnsServer, priorities, ips4, ips6, true);
-
-			final List<TlsSrv> result = new ArrayList<>();
-			for (final List<TlsSrv> s : priorities.values()) {
-				result.addAll(s);
-			}
-
-			final ArrayList<Bundle> values = new ArrayList<>();
-			if (result.size() == 0) {
-				DNSMessage response;
-				try {
-					response = client.query(host, TYPE.A, CLASS.IN, dnsServer.getHostAddress());
-					for (int i = 0; i < response.getAnswers().length; ++i) {
-						values.add(createNamePortBundle(host, 5222, response.getAnswers()[i].getPayload(), false));
-					}
-				} catch (SocketTimeoutException e) {
-					Log.d(Config.LOGTAG,"ignoring timeout exception when querying A record on "+dnsServer.getHostAddress());
-				}
-				try {
-					response = client.query(host, TYPE.AAAA, CLASS.IN, dnsServer.getHostAddress());
-					for (int i = 0; i < response.getAnswers().length; ++i) {
-						values.add(createNamePortBundle(host, 5222, response.getAnswers()[i].getPayload(), false));
-					}
-				} catch (SocketTimeoutException e) {
-					Log.d(Config.LOGTAG,"ignoring timeout exception when querying AAAA record on "+dnsServer.getHostAddress());
-				}
-				values.add(createNamePortBundle(host, 5222, false));
-				bundle.putParcelableArrayList("values", values);
-				return bundle;
-			}
-			for (final TlsSrv tlsSrv : result) {
-				final SRV srv = tlsSrv.srv;
-				if (ips6.containsKey(srv.getName())) {
-					values.add(createNamePortBundle(srv.getName(),srv.getPort(),ips6, tlsSrv.tls));
-				} else {
-					try {
-						DNSMessage response = client.query(srv.getName(), TYPE.AAAA, CLASS.IN, dnsServer.getHostAddress());
-						for (int i = 0; i < response.getAnswers().length; ++i) {
-							values.add(createNamePortBundle(srv.getName(), srv.getPort(), response.getAnswers()[i].getPayload(), tlsSrv.tls));
-						}
-					} catch (SocketTimeoutException e) {
-						Log.d(Config.LOGTAG,"ignoring timeout exception when querying AAAA record on "+dnsServer.getHostAddress());
-					}
-				}
-				if (ips4.containsKey(srv.getName())) {
-					values.add(createNamePortBundle(srv.getName(),srv.getPort(),ips4, tlsSrv.tls));
-				} else {
-					DNSMessage response = client.query(srv.getName(), TYPE.A, CLASS.IN, dnsServer.getHostAddress());
-					for(int i = 0; i < response.getAnswers().length; ++i) {
-						values.add(createNamePortBundle(srv.getName(),srv.getPort(),response.getAnswers()[i].getPayload(), tlsSrv.tls));
-					}
-				}
-				values.add(createNamePortBundle(srv.getName(), srv.getPort(), tlsSrv.tls));
-			}
-			bundle.putParcelableArrayList("values", values);
-		} catch (SocketTimeoutException e) {
-			bundle.putString("error", "timeout");
-		} catch (Exception e) {
-			bundle.putString("error", "unhandled");
-		}
-		return bundle;
-	}
-
-	private static Bundle createNamePortBundle(String name, int port, final boolean tls) {
-		Bundle namePort = new Bundle();
-		namePort.putString("name", name);
-		namePort.putBoolean("tls", tls);
-		namePort.putInt("port", port);
-		return namePort;
-	}
-
-	private static Bundle createNamePortBundle(String name, int port, Map<String, List<String>> ips, final boolean tls) {
-		Bundle namePort = new Bundle();
-		namePort.putString("name", name);
-		namePort.putBoolean("tls", tls);
-		namePort.putInt("port", port);
-		if (ips!=null) {
-			List<String> ip = ips.get(name);
-			Collections.shuffle(ip, new Random());
-			namePort.putString("ip", ip.get(0));
-		}
-		return namePort;
-	}
-
-	private static Bundle createNamePortBundle(String name, int port, Data data, final boolean tls) {
-		Bundle namePort = new Bundle();
-		namePort.putString("name", name);
-		namePort.putBoolean("tls", tls);
-		namePort.putInt("port", port);
-		if (data instanceof A) {
-			namePort.putString("ip", data.toString());
-		} else if (data instanceof AAAA) {
-			namePort.putString("ip","["+data.toString()+"]");
-		}
-		return namePort;
-	}
+    /**
+     * Queries the SRV record for an host from the given Domain Name Server.
+     * @param host the host to query for
+     * @param dnsServerAddress the DNS to query on
+     * @return TreeSet with SrvRecords.
+     */
+    private static final TreeSet<SrvRecord> querySrvRecord(String host, InetAddress dnsServerAddress) {
+        TreeSet<SrvRecord> result = new TreeSet<>();
+        querySrvRecord(host, dnsServerAddress, false, result);
+        querySrvRecord(host, dnsServerAddress, true, result);
+        return result;
+    }
+
+    private static final void querySrvRecord(String host, InetAddress dnsServerAddress, boolean tlsSrvRecord, TreeSet<SrvRecord> result) {
+        String qname = (tlsSrvRecord ? SECURE_CLIENT_SRV_PREFIX : CLIENT_SRV_PREFIX) + host;
+        String dnsServerHostAddress = dnsServerAddress.getHostAddress();
+        Logging.d("dns", "using dns server: " + dnsServerHostAddress + " to look up " + qname);
+        try {
+            DNSMessage message = client.query(qname, TYPE.SRV, CLASS.IN, dnsServerHostAddress);
+            Record[] rrset = message.getAnswers();
+            for (Record rr : rrset) {
+                Data d = rr.getPayload();
+                if (d instanceof SRV && NameUtil.idnEquals(qname, rr.getName())) {
+                    SRV srv = (SRV) d;
+                    SrvRecord srvRecord = new SrvRecord(srv.getPriority(), srv.getName(), srv.getPort(), tlsSrvRecord);
+                    result.add(srvRecord);
+                }
+            }
+        } catch (IOException e) {
+            Logging.d("dns", "Error while retrieving SRV record '" + qname + "' for '" + host + "' from DNS '" + dnsServerHostAddress + "': " + e.getMessage());
+        }
+    }
 
 	public static boolean isIp(final String server) {
 		return server != null && (
diff --git a/src/main/java/eu/siacs/conversations/xmpp/XmppConnection.java b/src/main/java/eu/siacs/conversations/xmpp/XmppConnection.java
index ab647a15..30d68a67 100644
--- a/src/main/java/eu/siacs/conversations/xmpp/XmppConnection.java
+++ b/src/main/java/eu/siacs/conversations/xmpp/XmppConnection.java
@@ -282,69 +282,54 @@ public class XmppConnection implements Runnable {
 				}
 				startXmpp();
 			} else {
-				final Bundle result = DNSHelper.getSRVRecord(account.getServer(), mXmppConnectionService);
-				final ArrayList<Parcelable>values = result.getParcelableArrayList("values");
-				for(Iterator<Parcelable> iterator = values.iterator(); iterator.hasNext();) {
-					final Bundle namePort = (Bundle) iterator.next();
-					try {
-						String srvRecordServer;
-						try {
-							srvRecordServer = IDN.toASCII(namePort.getString("name"));
-						} catch (final IllegalArgumentException e) {
-							// TODO: Handle me?`
-							srvRecordServer = "";
-						}
-						final int srvRecordPort = namePort.getInt("port");
-						final String srvIpServer = namePort.getString("ip");
-						// if tls is true, encryption is implied and must not be started
-						features.encryptionEnabled = namePort.getBoolean("tls");
-						final InetSocketAddress addr;
-						if (srvIpServer != null) {
-							addr = new InetSocketAddress(srvIpServer, srvRecordPort);
-							Log.d(Config.LOGTAG, account.getJid().toBareJid().toString()
-									+ ": using values from dns " + srvRecordServer
-									+ "[" + srvIpServer + "]:" + srvRecordPort + " tls: " + features.encryptionEnabled);
-						} else {
-							addr = new InetSocketAddress(srvRecordServer, srvRecordPort);
-							Log.d(Config.LOGTAG, account.getJid().toBareJid().toString()
-									+ ": using values from dns "
-									+ srvRecordServer + ":" + srvRecordPort + " tls: " + features.encryptionEnabled);
-						}
-
-						if (!features.encryptionEnabled) {
-							socket = new Socket();
-							socket.connect(addr, Config.SOCKET_TIMEOUT * 1000);
-						} else {
-							final TlsFactoryVerifier tlsFactoryVerifier = getTlsFactoryVerifier();
-							socket = tlsFactoryVerifier.factory.createSocket();
-
-							if (socket == null) {
-								throw new IOException("could not initialize ssl socket");
-							}
-
-							SSLSocketHelper.setSecurity((SSLSocket) socket);
-							SSLSocketHelper.setSNIHost(tlsFactoryVerifier.factory, (SSLSocket) socket, account.getServer().getDomainpart());
-							SSLSocketHelper.setAlpnProtocol(tlsFactoryVerifier.factory, (SSLSocket) socket, "xmpp-client");
-
-							socket.connect(addr, Config.SOCKET_TIMEOUT * 1000);
-
-							if (!tlsFactoryVerifier.verifier.verify(account.getServer().getDomainpart(), ((SSLSocket) socket).getSession())) {
-								Log.d(Config.LOGTAG, account.getJid().toBareJid() + ": TLS certificate verification failed");
-								throw new SecurityException();
-							}
-						}
-
-						if (startXmpp())
-							break; // successfully connected to server that speaks xmpp
-					} catch(final SecurityException e) {
-						throw e;
-					} catch (final Throwable e) {
-						Log.d(Config.LOGTAG, account.getJid().toBareJid().toString() + ": " + e.getMessage() +"("+e.getClass().getName()+")");
-						if (!iterator.hasNext()) {
-							throw new UnknownHostException();
-						}
-					}
-				}
+				final TreeSet<SrvRecord> srvRecords = DNSHelper.querySrvRecord(account.getServer());
+                if (srvRecords.isEmpty()) {
+                    socket = new Socket();
+                    try {
+                        socket.connect(new InetSocketAddress(account.getServer().getDomainpart(), DEFAULT_PORT), Config.SOCKET_TIMEOUT * 1000);
+                    } catch (IOException e) {
+                        throw new UnknownHostException();
+                    }
+                    startXmpp();
+                } else {
+                    for (SrvRecord srvRecord : srvRecords) {
+                        // if tls is true, encryption is implied and must not be started
+                        features.encryptionEnabled = srvRecord.isUseTls();
+                        TlsFactoryVerifier tlsFactoryVerifier = null;
+                        if (features.encryptionEnabled) {
+                            try {
+                                tlsFactoryVerifier = getTlsFactoryVerifier();
+                                socket = tlsFactoryVerifier.factory.createSocket();
+
+                                if (socket == null) {
+                                    throw new IOException("could not initialize ssl socket");
+                                }
+
+                                SSLSocketHelper.setSecurity((SSLSocket) socket);
+                                SSLSocketHelper.setSNIHost(tlsFactoryVerifier.factory, (SSLSocket) socket, account.getServer().getDomainpart());
+                                SSLSocketHelper.setAlpnProtocol(tlsFactoryVerifier.factory, (SSLSocket) socket, "xmpp-client");
+                            } catch (SecurityException e) {
+                                throw e;
+                            } catch (KeyManagementException e) {
+                                Logging.e("connection-init", "Error while creating TLS verifier factory: " + e.getMessage(), e);
+                                throw new SecurityException();
+                            }
+                        } else {
+                            socket = new Socket();
+                        }
+
+                        socket.connect(new InetSocketAddress(srvRecord.getName(), srvRecord.getPort()), Config.SOCKET_TIMEOUT * 1000);
+
+                        if (null != tlsFactoryVerifier && !tlsFactoryVerifier.verifier.verify(account.getServer().getDomainpart(), ((SSLSocket) socket).getSession())) {
+                            Log.d(Config.LOGTAG, account.getJid().toBareJid() + ": TLS certificate verification failed");
+                            throw new SecurityException();
+                        }
+
+                        if (startXmpp()) {
+                            break; // successfully connected to server that speaks xmpp
+                        }
+                    }
+                }
 			}
 			processStream();
 		} catch (final IncompatibleServerException e) {