squash-24

CHANGELOG.md

@@ -9,7 +9,14 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 ## [Unreleased]
 
 ### TODO for 0.3.0
+- BUG: System.setProperty(Constants.PROPERTY_DAEMON, "127.0.0.1");
+  leads to exception about missing TRC (instead of complaining about missing ":30255")
+  -> DOes this work with an IPv6 address (separaeting the port?)
+  -> Think about making the port optional, it is standardized to 30255 anyway
+  -> Move port to separate environment variable???? 
+- Make ResponsePath/RequestPath classes private. Make at least create() private... 
 - Demo that connects to Francois' website
+- Fix @Disabled tests
 - Support topofile port range
 - `ResponsePath` is now package private (not public anymore)
 - remove ScionAddress?
@@ -28,6 +35,12 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 - Support for bootstrapper TRC metadata. [#110](https://github.com/scionproto-contrib/jpan/pull/110)
 - Added `copy(...)` method for paths. [#111](https://github.com/scionproto-contrib/jpan/pull/111)
 - Added Scenario builder for unit tests. [#112](https://github.com/scionproto-contrib/jpan/pull/112)
+- Support shortcut and on-path detection during path construction. Also:
+  - New option `SCION_RESOLVER_MINIMIZE_REQUESTS`
+  - Fixed MTU calculations for link level MTU
+  - Path lists are ordered by hop count
+  - Path lists contain no duplicates
+  [#104](https://github.com/scionproto-contrib/jpan/pull/104)
 
 ### Changed
 - Clean up TODO and deprecation info. [#100](https://github.com/scionproto-contrib/jpan/pull/100) 

README.md

@@ -345,10 +345,18 @@ is configurable, see next section.
 
 ### Other Options
 
-| Option                                                                                                               | Java property           | Environment variable | Default value      |
-|----------------------------------------------------------------------------------------------------------------------|-------------------------|----------------------|--------------------|
-| Path expiry margin. Before sending a packet a new path is requested if the path is about to expire within X seconds. | `org.scion.pathExpiryMargin` | `SCION_PATH_EXPIRY_MARGIN`  | 10                 |
-| Location of `hosts` file. Multiple location can be specified separated by `;`.                                       | `org.scion.hostsFiles` | `SCION_HOSTS_FILES`  | `/etc/scion/hosts` |
+| Option                                                                                                               | Java property                         | Environment variable                 | Default value      |
+|----------------------------------------------------------------------------------------------------------------------|---------------------------------------|--------------------------------------|--------------------|
+| Path expiry margin. Before sending a packet a new path is requested if the path is about to expire within X seconds. | `org.scion.pathExpiryMargin`          | `SCION_PATH_EXPIRY_MARGIN`           | 10                 |
+| Location of `hosts` file. Multiple location can be specified separated by `;`.                                       | `org.scion.hostsFiles`                | `SCION_HOSTS_FILES`                  | `/etc/scion/hosts` |
+| Minimize segment requests to local AS at the cost of reduced range of path available.                                | `org.scion.resolver.minimizeRequests` | `SCION_RESOLVER_MINIMIZE_REQUESTS`   | `false`            |
+
+`SCION_RESOLVER_MINIMIZE_REQUESTS` is a non-standard option that request CORE segments only of other 
+path can be constructed. This may reduce response time when requesting new paths. It is very likely,
+but not guaranteed, that the shortest path (fewest hops) will be available. 
+If this property is not set (= default), CORE segments are always requested, resulting in additional
+path options. While these additional path options almost always result in longer paths, they may have 
+other advantages.  
 
 ## FAQ / Troubleshooting
 

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

@@ -16,6 +16,7 @@
 
 public final class Constants {
   public static final int SCMP_PORT = 30041;
+
   /**
    * @deprecated Dispatcher support will be removed soon.
    */
@@ -64,6 +65,15 @@ public final class Constants {
   /** Time (in seconds) before expiration at which a paths is automatically renewed. */
   public static final int DEFAULT_PATH_EXPIRY_MARGIN = 10;
 
+  /** Enable minimization of segment requests during path construction. */
+  public static final String PROPERTY_RESOLVER_MINIMIZE_REQUESTS =
+      "SCION_RESOLVER_MINIMIZE_REQUESTS";
+
+  /** Enable minimization of segment requests during path construction. */
+  public static final String ENV_RESOLVER_MINIMIZE_REQUESTS = "org.scion.resolver.minimizeRequests";
+
+  public static final boolean DEFAULT_RESOLVER_MINIMIZE_REQUESTS = false;
+
   /**
    * Disable usage of OS search domains for DNS lookup, e.g. from /etc/resolv.conf. This needs to be
    * disabled for JUnit testing.

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

@@ -73,6 +73,7 @@ public class ScionService {
   private final DaemonServiceGrpc.DaemonServiceBlockingStub daemonStub;
   private final SegmentLookupServiceGrpc.SegmentLookupServiceBlockingStub segmentStub;
 
+  private final boolean minimizeRequests;
   private final ManagedChannel channel;
   private static final long ISD_AS_NOT_SET = -1;
   private final AtomicLong localIsdAs = new AtomicLong(ISD_AS_NOT_SET);
@@ -89,6 +90,11 @@ protected enum Mode {
   }
 
   protected ScionService(String addressOrHost, Mode mode) {
+    minimizeRequests =
+        ScionUtil.getPropertyOrEnv(
+            Constants.PROPERTY_RESOLVER_MINIMIZE_REQUESTS,
+            Constants.ENV_RESOLVER_MINIMIZE_REQUESTS,
+            Constants.DEFAULT_RESOLVER_MINIMIZE_REQUESTS);
     if (mode == Mode.DAEMON) {
       LOG.info("Bootstrapping with daemon: target={}", addressOrHost);
       channel = Grpc.newChannelBuilder(addressOrHost, InsecureChannelCredentials.create()).build();
@@ -596,7 +602,16 @@ private Long parseTxtRecordToIA(String txtEntry) {
 
   // Do not expose protobuf types on API!
   List<Daemon.Path> getPathListCS(long srcIsdAs, long dstIsdAs) {
-    return Segments.getPaths(segmentStub, bootstrapper, srcIsdAs, dstIsdAs);
+    List<Daemon.Path> list =
+        Segments.getPaths(segmentStub, bootstrapper, srcIsdAs, dstIsdAs, minimizeRequests);
+    if (LOG.isInfoEnabled()) {
+      LOG.info(
+          "Path found between {} and {}: {}",
+          ScionUtil.toStringIA(srcIsdAs),
+          ScionUtil.toStringIA(dstIsdAs),
+          list.size());
+    }
+    return list;
   }
 
   /**