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-rw-r--r--src/eu/siacs/conversations/utils/DNSHelper.java191
1 files changed, 100 insertions, 91 deletions
diff --git a/src/eu/siacs/conversations/utils/DNSHelper.java b/src/eu/siacs/conversations/utils/DNSHelper.java
index 3197acb1..c5a3eeb0 100644
--- a/src/eu/siacs/conversations/utils/DNSHelper.java
+++ b/src/eu/siacs/conversations/utils/DNSHelper.java
@@ -1,125 +1,134 @@
package eu.siacs.conversations.utils;
-import java.io.ByteArrayOutputStream;
+import de.measite.minidns.Client;
+import de.measite.minidns.DNSMessage;
+import de.measite.minidns.Record;
+import de.measite.minidns.Record.TYPE;
+import de.measite.minidns.Record.CLASS;
+import de.measite.minidns.record.SRV;
+import de.measite.minidns.record.Data;
+
import java.io.IOException;
-import java.lang.reflect.InvocationTargetException;
-import java.lang.reflect.Method;
-import java.net.DatagramPacket;
-import java.net.DatagramSocket;
import java.net.InetAddress;
import java.util.ArrayList;
+import java.util.Collections;
import java.util.Random;
+import java.util.TreeMap;
import android.os.Bundle;
import android.util.Log;
public class DNSHelper {
+ protected static Client client = new Client();
+
public static Bundle getSRVRecord(String host) throws IOException {
- InetAddress ip = InetAddress.getByName("8.8.8.8");
- try {
- Class<?> SystemProperties = Class
- .forName("android.os.SystemProperties");
- Method method = SystemProperties.getMethod("get",
- new Class[] { String.class });
- ArrayList<String> servers = new ArrayList<String>();
- for (String name : new String[] { "net.dns1", "net.dns2",
- "net.dns3", "net.dns4", }) {
- String value = (String) method.invoke(null, name);
-
- if (value != null && !"".equals(value)
- && !servers.contains(value)) {
- ip = InetAddress.getByName(value);
- servers.add(value);
- Bundle result = queryDNS(host, ip);
- if (!result.containsKey("error")||("nosrv".equals(result.getString("error")))) {
- return result;
- }
+ String dns[] = client.findDNS();
+
+ if (dns != null) {
+ // we have a list of DNS servers, let's go
+ for (String dnsserver : dns) {
+ InetAddress ip = InetAddress.getByName(dnsserver);
+ Bundle b = queryDNS(host, ip);
+ if (b.containsKey("name")) {
+ return b;
}
}
- } catch (Exception e) {
- Log.d("xmppService","error during system calls");
}
- ip = InetAddress.getByName("8.8.8.8");
- return queryDNS(host, ip);
+
+ // fallback
+ return queryDNS(host, InetAddress.getByName("8.8.8.8"));
}
public static Bundle queryDNS(String host, InetAddress dnsServer) {
Bundle namePort = new Bundle();
try {
- Log.d("xmppService", "using dns server: " + dnsServer.toString()
+ Log.d("xmppService", "using dns server: " + dnsServer.getHostAddress()
+ " to look up " + host);
- String[] hostParts = host.split("\\.");
- byte[] transId = new byte[2];
- Random random = new Random();
- random.nextBytes(transId);
- byte[] header = { 0x01, 0x20, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00,
- 0x00, 0x01, 0x0c, 0x5f, 0x78, 0x6d, 0x70, 0x70, 0x2d, 0x63,
- 0x6c, 0x69, 0x65, 0x6e, 0x74, 0x04, 0x5f, 0x74, 0x63, 0x70 };
- byte[] rest = { 0x00, 0x00, 0x21, 0x00, 0x01, 0x00, 0x00, 0x29,
- 0x10, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
- ByteArrayOutputStream output = new ByteArrayOutputStream();
- output.write(transId);
- output.write(header);
- for (int i = 0; i < hostParts.length; ++i) {
- char[] tmpChars = hostParts[i].toCharArray();
- byte[] tmp = new byte[tmpChars.length];
- for (int j = 0; j < tmpChars.length; ++j) {
- tmp[j] = (byte) tmpChars[j];
+ DNSMessage message =
+ client.query(
+ "_xmpp-client._tcp." + host,
+ TYPE.SRV,
+ CLASS.IN,
+ dnsServer.getHostAddress());
+
+ // How should we handle priorities and weight?
+ // Wikipedia has a nice article about priorities vs. weights:
+ // https://en.wikipedia.org/wiki/SRV_record#Provisioning_for_high_service_availability
+
+ // we bucket the SRV records based on priority, pick per priority
+ // a random order respecting the weight, and dump that priority by
+ // priority
+
+ TreeMap<Integer, ArrayList<SRV>> priorities =
+ new TreeMap<Integer, ArrayList<SRV>>();
+
+ for (Record rr : message.getAnswers()) {
+ Data d = rr.getPayload();
+ if (d instanceof SRV) {
+ SRV srv = (SRV) d;
+ if (!priorities.containsKey(srv.getPriority())) {
+ priorities.put(srv.getPriority(), new ArrayList<SRV>(2));
+ }
+ priorities.get(srv.getPriority()).add(srv);
}
- output.write(tmp.length);
- output.write(tmp);
}
- output.write(rest);
- byte[] sendPaket = output.toByteArray();
- int realLenght = sendPaket.length - 11;
- DatagramPacket packet = new DatagramPacket(sendPaket,
- sendPaket.length, dnsServer, 53);
- DatagramSocket datagramSocket = new DatagramSocket();
- datagramSocket.send(packet);
- byte[] receiveData = new byte[1024];
-
- DatagramPacket receivePacket = new DatagramPacket(receiveData,
- receiveData.length);
- datagramSocket.setSoTimeout(7000); //die sieben ist meine zahl
- datagramSocket.receive(receivePacket);
- if (receiveData[3] != -128) {
- namePort.putString("error", "nosrv");
- return namePort;
- }
- namePort.putInt(
- "port",
- calcPort(receiveData[realLenght + 16],
- receiveData[realLenght + 17]));
- int i = realLenght + 18;
- int wordLenght = 0;
- StringBuilder builder = new StringBuilder();
- while (receiveData[i] != 0) {
- if (wordLenght > 0) {
- builder.append((char) receiveData[i]);
- --wordLenght;
- } else {
- wordLenght = receiveData[i];
- builder.append(".");
+
+ Random rnd = new Random();
+ ArrayList<SRV> result = new ArrayList<SRV>(priorities.size() * 2 + 1);
+ for (ArrayList<SRV> s: priorities.values()) {
+
+ // trivial case
+ if (s.size() <= 1) {
+ result.addAll(s);
+ continue;
+ }
+
+ long totalweight = 0l;
+ for (SRV srv: s) {
+ totalweight += srv.getWeight();
}
- ++i;
+
+ while (totalweight > 0l && s.size() > 0) {
+ long p = (rnd.nextLong() & 0x7fffffffffffffffl) % totalweight;
+ int i = 0;
+ while (p > 0) {
+ p -= s.get(i++).getPriority();
+ }
+ i--;
+ // remove is expensive, but we have only a few entries anyway
+ SRV srv = s.remove(i);
+ totalweight -= srv.getWeight();
+ result.add(srv);
+ }
+
+ Collections.shuffle(s, rnd);
+ result.addAll(s);
+
}
- builder.replace(0, 1, "");
- byte type = receiveData[i + 1];
- byte type2 = receiveData[i + 2];
- if ((type == -64) || (type == type2)) {
- namePort.putString("name", builder.toString());
- return namePort;
- } else {
- Log.d("xmppService", "type=" + type + " type2=" + type2 + " "
- + builder.toString());
+
+ if (result.size() == 0) {
namePort.putString("error", "nosrv");
return namePort;
}
+ // we now have a list of servers to try :-)
+
+ // classic name/port pair
+ namePort.putString("name", result.get(0).getName());
+ namePort.putInt("port", result.get(0).getPort());
+
+ // add all other records
+ int i = 0;
+ for (SRV srv : result) {
+ namePort.putString("name" + i, srv.getName());
+ namePort.putInt("port" + i, srv.getPort());
+ i++;
+ }
+
} catch (IOException e) {
- Log.d("xmppService", "io execpiton during dns");
+ Log.e("xmppService", "io execpiton during dns", e);
namePort.putString("error", "timeout");
- return namePort;
}
+ return namePort;
}
static int calcPort(byte hb, byte lb) {
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-10 13:43:44 +0000