Configurable DNS search domain

CHANGELOG.md

@@ -45,6 +45,8 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
   [#114](https://github.com/scionproto-contrib/jpan/pull/114)
 - Improved path duplication filtering.
   [#117](https://github.com/scionproto-contrib/jpan/pull/117)
+- Added environment variable / property for DNS search domain.
+  [#119](https://github.com/scionproto-contrib/jpan/pull/119)
 
 ### Changed
 - Clean up TODO and deprecation info. [#100](https://github.com/scionproto-contrib/jpan/pull/100) 

README.md

@@ -330,13 +330,15 @@ attempt to get network information in the following order until it succeeds:
 The reason that the daemon is checked last is that it has a default setting (`localhost:30255`) 
 while the other options are skipped if no property or environment variable is defined. 
 
-| Option                              | Java property                       | Environment variable          | Default value   |
-|-------------------------------------|-------------------------------------|-------------------------------|-----------------|
-| Daemon port, IP, or IP:port         | `org.scion.daemon`                  | `SCION_DAEMON`                | localhost:30255 | 
-| Bootstrap topology file path        | `org.scion.bootstrap.topoFile`      | `SCION_BOOTSTRAP_TOPO_FILE`   |                 | 
-| Bootstrap server host               | `org.scion.bootstrap.host`          | `SCION_BOOTSTRAP_HOST`        |                 |
-| Bootstrap DNS NAPTR entry host name | `org.scion.bootstrap.naptr.name`    | `SCION_BOOTSTRAP_NAPTR_NAME`  |                 | 
-| Bootstrap DNS NAPTR entry host name | `org.scion.test.useOsSearchDomains` | `SCION_USE_OS_SEARCH_DOMAINS` | true            | 
+| Option                                       | Java property                                       | Environment variable           | Default value   |
+|----------------------------------------------|-----------------------------------------------------|--------------------------------|-----------------|
+| Daemon port, IP, or IP:port                  | `org.scion.daemon`                                  | `SCION_DAEMON`                 | localhost:30255 | 
+| Bootstrap topology file path                 | `org.scion.bootstrap.topoFile`                      | `SCION_BOOTSTRAP_TOPO_FILE`    |                 | 
+| Bootstrap server host                        | `org.scion.bootstrap.host`                          | `SCION_BOOTSTRAP_HOST`         |                 |
+| Bootstrap DNS NAPTR entry host name          | `org.scion.bootstrap.naptr.name`                    | `SCION_BOOTSTRAP_NAPTR_NAME`   |                 | 
+| List of DNS search domains                   | `org.scion.dnsSearchDomains` | `SCION_DNS_SEARCH_DOMAINS`    |                 |
+| Use OS search domains, e.g. /etc/resolv.conf | `org.scion.test.useOsSearchDomains`    | `SCION_USE_OS_SEARCH_DOMAINS`  | true            |
+
 
 ### DNS
 JPAN will check the OS default DNS server to resolve SCION addresses.
@@ -377,6 +379,13 @@ file into you resources folder, or enable logging programmatically with
 `System.setProperty(org.slf4j.impl.SimpleLogger.DEFAULT_LOG_LEVEL_KEY, "INFO");` 
 before using *any* JPAN code. 
 
+### No DNS search domain found. Please check your /etc/resolv.conf or similar. / No DNS record found for bootstrap server.
+
+You may have to set the DNS search domain explicitly to a server with SCION NAPTR records. For example (works only if you are inside ETH):  
+```java
+System.setProperty(Constants.PROPERTY_DNS_SEARCH_DOMAINS, "ethz.ch.");
+```
+
 ### Local testbed (scionproto) does not contain any path
 
 A common problem is that the certificates of the testbed have expired (default validity: 3 days).

pom.xml

@@ -10,7 +10,7 @@
     <properties>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
 
-        <scion.dnsjava.version>3.5.3</scion.dnsjava.version>
+        <scion.dnsjava.version>3.6.1</scion.dnsjava.version>
         <scion.google-java-format.version>1.22.0</scion.google-java-format.version>
         <scion.io-grpc.version>1.63.0</scion.io-grpc.version>
         <scion.junit.version>5.10.1</scion.junit.version>

src/main/java/org/scion/jpan/Constants.java

@@ -85,6 +85,11 @@ public final class Constants {
   public static final String ENV_USE_OS_SEARCH_DOMAINS = "SCION_USE_OS_SEARCH_DOMAINS";
   public static final boolean DEFAULT_USE_OS_SEARCH_DOMAINS = true;
 
+  /** Provide list of DNS search domains. */
+  public static final String PROPERTY_DNS_SEARCH_DOMAINS = "org.scion.dnsSearchDomains";
+
+  public static final String ENV_DNS_SEARCH_DOMAINS = "SCION_DNS_SEARCH_DOMAINS";
+
   /**
    * Non-public property that allows specifying DNS TXT entries for debugging. Example with two
    * entries: server1.com="scion=1-ff00:0:110,127.0.0.1";server2.ch="scion=1-ff00:0:112,::1"

src/main/java/org/scion/jpan/ScionService.java

@@ -21,11 +21,13 @@
 import static org.scion.jpan.Constants.ENV_BOOTSTRAP_NAPTR_NAME;
 import static org.scion.jpan.Constants.ENV_BOOTSTRAP_TOPO_FILE;
 import static org.scion.jpan.Constants.ENV_DAEMON;
+import static org.scion.jpan.Constants.ENV_DNS_SEARCH_DOMAINS;
 import static org.scion.jpan.Constants.ENV_USE_OS_SEARCH_DOMAINS;
 import static org.scion.jpan.Constants.PROPERTY_BOOTSTRAP_HOST;
 import static org.scion.jpan.Constants.PROPERTY_BOOTSTRAP_NAPTR_NAME;
 import static org.scion.jpan.Constants.PROPERTY_BOOTSTRAP_TOPO_FILE;
 import static org.scion.jpan.Constants.PROPERTY_DAEMON;
+import static org.scion.jpan.Constants.PROPERTY_DNS_SEARCH_DOMAINS;
 import static org.scion.jpan.Constants.PROPERTY_USE_OS_SEARCH_DOMAINS;
 
 import io.grpc.*;
@@ -184,10 +186,13 @@ static ScionService defaultService() {
       }
 
       // try normal network
+      String searchDomain =
+          ScionUtil.getPropertyOrEnv(PROPERTY_DNS_SEARCH_DOMAINS, ENV_DNS_SEARCH_DOMAINS);
       if (ScionUtil.getPropertyOrEnv(
-          PROPERTY_USE_OS_SEARCH_DOMAINS,
-          ENV_USE_OS_SEARCH_DOMAINS,
-          DEFAULT_USE_OS_SEARCH_DOMAINS)) {
+              PROPERTY_USE_OS_SEARCH_DOMAINS,
+              ENV_USE_OS_SEARCH_DOMAINS,
+              DEFAULT_USE_OS_SEARCH_DOMAINS)
+          || searchDomain != null) {
         String dnsResolver = DNSHelper.searchForDiscoveryService();
         if (dnsResolver != null) {
           defaultService = new ScionService(dnsResolver, Mode.BOOTSTRAP_SERVER_IP);

src/main/java/org/scion/jpan/internal/DNSHelper.java

@@ -14,22 +14,18 @@
 
 package org.scion.jpan.internal;
 
+import static org.scion.jpan.Constants.ENV_DNS_SEARCH_DOMAINS;
+import static org.scion.jpan.Constants.PROPERTY_DNS_SEARCH_DOMAINS;
+
 import java.io.IOException;
 import java.net.InetAddress;
 import java.util.List;
 import java.util.function.Function;
 import org.scion.jpan.ScionRuntimeException;
+import org.scion.jpan.ScionUtil;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
-import org.xbill.DNS.AAAARecord;
-import org.xbill.DNS.ARecord;
-import org.xbill.DNS.Lookup;
-import org.xbill.DNS.NAPTRRecord;
-import org.xbill.DNS.Name;
-import org.xbill.DNS.Record;
-import org.xbill.DNS.TXTRecord;
-import org.xbill.DNS.TextParseException;
-import org.xbill.DNS.Type;
+import org.xbill.DNS.*;
 
 public class DNSHelper {
 
@@ -64,7 +60,7 @@
   }
 
   public static <R> R queryTXT(Name name, String key, Function<String, R> valueParser) {
-    Record[] records = new Lookup(name, Type.TXT).run();
+    org.xbill.DNS.Record[] records = new Lookup(name, Type.TXT).run();
     if (records == null) {
       return null;
     }
@@ -86,7 +82,7 @@
   }
 
   public static InetAddress queryA(Name hostName) {
-    Record[] recordsA = new Lookup(hostName, Type.A).run();
+    org.xbill.DNS.Record[] recordsA = new Lookup(hostName, Type.A).run();
     if (recordsA == null) {
       throw new ScionRuntimeException("No DNS A entry found for host: " + hostName);
     }
@@ -95,7 +91,7 @@
   }
 
   public static InetAddress queryAAAA(Name hostName) {
-    Record[] recordsA = new Lookup(hostName, Type.AAAA).run();
+    org.xbill.DNS.Record[] recordsA = new Lookup(hostName, Type.AAAA).run();
     if (recordsA == null) {
       throw new ScionRuntimeException("No DNS AAAA entry found for host: " + hostName);
     }
@@ -104,9 +100,30 @@
   }
 
   public static String searchForDiscoveryService() {
+    String searchDomains =
+        ScionUtil.getPropertyOrEnv(PROPERTY_DNS_SEARCH_DOMAINS, ENV_DNS_SEARCH_DOMAINS);
+    if (searchDomains != null) {
+      for (String domain : searchDomains.split(";")) {
+        LOG.debug(
+            "Checking discovery service domain from environment variable/property: {}", domain);
+        try {
+          String a = getScionDiscoveryAddress(Name.fromString(domain));
+          if (a != null) {
+            return a;
+          }
+        } catch (TextParseException e) {
+          throw new ScionRuntimeException(e);
+        }
+      }
+    }
+
     List<Name> domains = Lookup.getDefaultSearchPath();
     if (domains.isEmpty()) {
-      LOG.warn("No DNS search domain found. Please check your /etc/resolv.conf or similar.");
+      LOG.warn(
+          "No DNS search domain found. Please check your /etc/resolv.conf or similar. You can also specify a domain via "
+              + ENV_DNS_SEARCH_DOMAINS
+              + " or "
+              + PROPERTY_DNS_SEARCH_DOMAINS);
     }
     for (Name domain : domains) {
       LOG.debug("Checking discovery service domain: {}", domain);
@@ -123,7 +140,7 @@
   }
 
   private static String getScionDiscoveryAddress(Name hostName) {
-    Record[] records = new Lookup(hostName, Type.NAPTR).run();
+    org.xbill.DNS.Record[] records = new Lookup(hostName, Type.NAPTR).run();
     if (records == null) {
       LOG.debug("Checking discovery service NAPTR: no records found");
       return null;

src/main/java/org/scion/jpan/internal/PathRawParser.java

@@ -133,9 +133,10 @@
   }
 
   public int getSegmentCount() {
-    int nSegmentCount = 1;
-    nSegmentCount += segLen[1] > 0 ? 1 : 0;
-    nSegmentCount += segLen[2] > 0 ? 1 : 0;
+    int nSegmentCount = 0;
+    for (int i = 0; i < segLen.length; i++) {
+      nSegmentCount += segLen[i] > 0 ? 1 : 0;
+    }
     return nSegmentCount;
   }
 

src/test/java/org/scion/jpan/api/ScionServiceTest.java

@@ -540,4 +540,24 @@ void testDomainSearchResolver() throws IOException {
       MockNetwork.stopTiny();
     }
   }
+
+  @Test
+  void testDomainSearchResolver_PROPERTY() throws IOException {
+    MockNetwork.startTiny(MockNetwork.Mode.NAPTR);
+    try {
+      // Change to use custom search domain
+      System.setProperty(
+          Constants.PROPERTY_DNS_SEARCH_DOMAINS, MockBootstrapServer.TOPO_HOST + ".");
+      Lookup.setDefaultSearchPath("x.y.z."); // Invalid main path
+      // Lookup topology server
+      String address = MockNetwork.getTopoServer().getAddress().toString();
+      assertEquals(address.substring(1), DNSHelper.searchForDiscoveryService());
+      ScionService service = Scion.defaultService();
+      assertEquals(MockNetwork.getTopoServer().getLocalIsdAs(), service.getLocalIsdAs());
+    } finally {
+      Lookup.setDefaultSearchPath(Collections.emptyList());
+      MockNetwork.stopTiny();
+      System.clearProperty(Constants.PROPERTY_DNS_SEARCH_DOMAINS);
+    }
+  }
 }

src/test/java/org/scion/jpan/testutil/JUnitSetUp.java

@@ -70,6 +70,7 @@ public void beforeEach(ExtensionContext context) {
     System.clearProperty(Constants.PROPERTY_BOOTSTRAP_NAPTR_NAME);
     System.clearProperty(Constants.PROPERTY_BOOTSTRAP_HOST);
     System.clearProperty(Constants.PROPERTY_DAEMON);
+    System.clearProperty(Constants.PROPERTY_DNS_SEARCH_DOMAINS);
     System.clearProperty(Constants.PROPERTY_HOSTS_FILES);
     System.setProperty(Constants.PROPERTY_USE_OS_SEARCH_DOMAINS, "false");
     if (failed) {