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refactored resolver to fall back to DNS and use reliable method

This commit is contained in:
Daniel Gultsch 2017-06-25 22:46:56 +02:00
parent 4faf0f2ec9
commit 6dad1c0dde
1 changed files with 35 additions and 13 deletions
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46
src/main/java/eu/siacs/conversations/utils/Resolver.java
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@ -12,10 +12,14 @@ import java.util.List;
import de.measite.minidns.DNSClient;
import de.measite.minidns.DNSName;
import de.measite.minidns.dnssec.DNSSECResultNotAuthenticException;
import de.measite.minidns.dnssec.DNSSECValidationFailedException;
import de.measite.minidns.hla.DnssecResolverApi;
import de.measite.minidns.hla.ResolverApi;
import de.measite.minidns.hla.ResolverResult;
import de.measite.minidns.record.A;
import de.measite.minidns.record.AAAA;
import de.measite.minidns.record.Data;
import de.measite.minidns.record.InternetAddressRR;
import de.measite.minidns.record.SRV;
import eu.siacs.conversations.Config;
@ -26,8 +30,6 @@ public class Resolver {
private static final String STARTTLS_SERICE = "_xmpp-client";
public static void registerLookupMechanism(Context context) {
DNSClient.addDnsServerLookupMechanism(new AndroidUsingLinkProperties(context));
}
@ -36,29 +38,33 @@ public class Resolver {
List<Result> results = new ArrayList<>();
try {
results.addAll(resolveSrv(domain,true));
} catch (Throwable t) {
Log.d(Config.LOGTAG,Resolver.class.getSimpleName()+": "+t.getMessage());
} catch (IOException e) {
Log.d(Config.LOGTAG,Resolver.class.getSimpleName()+": "+e.getMessage());
}
try {
results.addAll(resolveSrv(domain,false));
} catch (Throwable t) {
Log.d(Config.LOGTAG,Resolver.class.getSimpleName()+": "+t.getMessage());
} catch (IOException e) {
Log.d(Config.LOGTAG,Resolver.class.getSimpleName()+": "+e.getMessage());
}
if (results.size() == 0) {
results.add(Result.createDefault(domain));
}
Collections.sort(results);
Log.d(Config.LOGTAG,Resolver.class.getSimpleName()+": "+results.toString());
return results;
}
private static List<Result> resolveSrv(String domain, final boolean directTls) throws IOException {
if (Thread.interrupted()) {
return Collections.emptyList();
}
DNSName dnsName = DNSName.from((directTls ? DIRECT_TLS_SERVICE : STARTTLS_SERICE)+"._tcp."+domain);
ResolverResult<SRV> result = DnssecResolverApi.INSTANCE.resolveDnssecReliable(dnsName,SRV.class);
ResolverResult<SRV> result = resolveWithFallback(dnsName,SRV.class);
List<Result> results = new ArrayList<>();
for(SRV record : result.getAnswersOrEmptySet()) {
boolean added = results.addAll(resolveIp(record,A.class,result.isAuthenticData(),directTls));
added |= results.addAll(resolveIp(record,AAAA.class,result.isAuthenticData(),directTls));
if (!added) {
final boolean addedIPv4 = results.addAll(resolveIp(record,A.class,result.isAuthenticData(),directTls));
results.addAll(resolveIp(record,AAAA.class,result.isAuthenticData(),directTls));
if (!addedIPv4 && !Thread.interrupted()) {
Result resolverResult = Result.fromRecord(record, directTls);
resolverResult.authenticated = resolverResult.isAuthenticated();
results.add(resolverResult);
@ -68,9 +74,12 @@ public class Resolver {
}
private static <D extends InternetAddressRR> List<Result> resolveIp(SRV srv, Class<D> type, boolean authenticated, boolean directTls) {
if (Thread.interrupted()) {
return Collections.emptyList();
}
List<Result> list = new ArrayList<>();
try {
ResolverResult<D> results = DnssecResolverApi.INSTANCE.resolveDnssecReliable(srv.name, type);
ResolverResult<D> results = resolveWithFallback(srv.name,type);
for (D record : results.getAnswersOrEmptySet()) {
Result resolverResult = Result.fromRecord(srv, directTls);
resolverResult.authenticated = results.isAuthenticData() && authenticated;
@ -83,6 +92,15 @@ public class Resolver {
return list;
}
private static <D extends Data> ResolverResult<D> resolveWithFallback(DNSName dnsName, Class<D> type) throws IOException {
try {
return DnssecResolverApi.INSTANCE.resolveDnssecReliable(dnsName, type);
} catch (DNSSECValidationFailedException | DNSSECResultNotAuthenticException e) {
Log.d(Config.LOGTAG,Resolver.class.getSimpleName()+": error resolving "+type.getSimpleName()+" with DNSSEC. Trying DNS instead "+e.getMessage());
return ResolverApi.INSTANCE.resolve(dnsName, type);
}
}
public static class Result implements Comparable<Result> {
private InetAddress ip;
private DNSName hostname;
@ -127,9 +145,13 @@ public class Resolver {
public int compareTo(@NonNull Result result) {
if (result.priority == priority) {
if (directTls == result.directTls) {
if (ip == null && result.ip == null) {
return 0;
} else {
return directTls ? 1 : -1;
return ip != null ? -1 : 1;
}
} else {
return directTls ? -1 : 1;
}
} else {
return priority - result.priority;