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Use raw DNS response

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M66B
2024-01-04 09:47:37 +01:00
parent a55337ea09
commit 72731ccbd2
1 changed files with 19 additions and 31 deletions
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50
app/src/main/java/eu/faircode/email/DnsHelper.java
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@@ -42,10 +42,10 @@ import org.minidns.hla.ResolverApi;
import org.minidns.hla.ResolverResult;
import org.minidns.record.A;
import org.minidns.record.AAAA;
import org.minidns.record.CNAME;
import org.minidns.record.Data;
import org.minidns.record.MX;
import org.minidns.record.NS;
import org.minidns.record.Record;
import org.minidns.record.SRV;
import org.minidns.record.TXT;
import org.minidns.source.AbstractDnsDataSource;
@@ -73,7 +73,6 @@ public class DnsHelper {
private static final String DEFAULT_DNS = "84.200.69.80";
private static final int CHECK_TIMEOUT = 5; // seconds
private static final int LOOKUP_TIMEOUT = 15; // seconds
private static final int MAX_FOLLOW = 5; // cnames
static void checkMx(Context context, Address[] addresses) throws UnknownHostException {
if (addresses == null)
@@ -84,7 +83,7 @@ public class DnsHelper {
String domain = UriHelper.getEmailDomain(email);
if (domain == null)
continue;
DnsRecord[] records = lookup(context, domain, "mx", CHECK_TIMEOUT, MAX_FOLLOW, false);
DnsRecord[] records = _lookup(context, domain, "mx", CHECK_TIMEOUT, false);
if (records.length == 0)
throw new UnknownHostException(domain);
}
@@ -92,24 +91,7 @@ public class DnsHelper {
@NonNull
static DnsRecord[] lookup(Context context, String name, String type) {
return lookup(context, name, type, LOOKUP_TIMEOUT, MAX_FOLLOW, false);
}
@NonNull
private static DnsRecord[] lookup(Context context, String name, String type, int timeout, int max_depth, boolean require_authentic) {
DnsRecord[] records = _lookup(context, name, type, timeout, require_authentic);
if (records.length == 0 &&
max_depth > 0 &&
!"ns".equals(type)) { // mx is not allowed, but used in practice anyway
DnsRecord[] cnames = _lookup(context, name, "cname", timeout, require_authentic);
List<DnsRecord> followed = new ArrayList<>();
for (DnsRecord cname : cnames) {
DnsRecord[] r = lookup(context, cname.response, type, timeout, max_depth - 1, require_authentic);
followed.addAll(Arrays.asList(r));
}
return followed.toArray(new DnsRecord[0]);
}
return records;
return _lookup(context, name, type, LOOKUP_TIMEOUT, false);
}
@NonNull
@@ -142,9 +124,6 @@ public class DnsHelper {
case "aaaa":
clazz = AAAA.class;
break;
case "cname":
clazz = CNAME.class;
break;
default:
throw new IllegalArgumentException(type);
}
@@ -251,10 +230,20 @@ public class DnsHelper {
List<DnsRecord> result = new ArrayList<>();
Set<? extends Data> answers = data.getAnswers();
if (answers != null)
for (Data answer : answers) {
Log.i("DNS answer=" + answer);
DnsMessage raw = data.getRawAnswer();
List<Record<? extends Data>> answers = (raw == null ? null : raw.answerSection);
Log.i("DNS answers=" + (answers == null ? "n/a" : answers.size()));
if (answers != null) {
Record.TYPE expectedType = data.getQuestion().type;
for (Record<? extends Data> record : answers) {
if (record.type != expectedType) {
Log.i("DNS skip=" + record);
continue;
}
Data answer = record.getPayload();
Log.i("DNS record=" + record + " answer=" + answer);
if (answer instanceof NS) {
NS ns = (NS) answer;
result.add(new DnsRecord(ns.getTarget().toString()));
@@ -291,12 +280,11 @@ public class DnsHelper {
} else if (answer instanceof AAAA) {
AAAA aaaa = (AAAA) answer;
result.add(new DnsRecord(aaaa.getInetAddress()));
} else if (answer instanceof CNAME) {
CNAME cname = (CNAME) answer;
result.add(new DnsRecord(cname.target.toString()));
} else
throw new IllegalArgumentException(answer.getClass().getName());
}
}
for (DnsRecord record : result) {
record.query = name;