SCMP echo problems, see #96

CHANGELOG.md

@@ -33,6 +33,8 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
   [#94](https://github.com/scionproto-contrib/jpan/pull/94)
 - **BREAKING CHANGE**: removed `RequestPath` and `ScionAddress` from public API.
   [#95](https://github.com/scionproto-contrib/jpan/pull/95)
+- Better error message for SCMP echo in local AS 
+  [#96](https://github.com/scionproto-contrib/jpan/issues/96)
 
 ### Fixed
 - Fixed locking and resizing of buffers. [#68](https://github.com/scionproto-contrib/jpan/pull/68)

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

@@ -43,9 +43,17 @@ static PathMetadata create(Daemon.Path path, InetAddress dstIP, int dstPort) {
   private PathMetadata(Daemon.Path path, InetAddress dstIP, int dstPort) {
     this.pathProtoc = path;
     this.pathRaw = path.getRaw().toByteArray();
+    // path length 0 means "local AS"
     if (getRawPath().length == 0) {
-      // local AS has path length 0
+      // See issue https://github.com/scionproto-contrib/jpan/issues/96
+      //      if (dstIP.isAnyLocalAddress()) {
+      //        // This is an SCMP request
+      //        ScionService service = Scion.defaultService();
+      //        firstHop =
+      // ScionUtil.parseInetSocketAddress(service.getBorderRouterStrings().get(0));
+      //      } else {
       firstHop = new InetSocketAddress(dstIP, dstPort);
+      //      }
     } else {
       firstHop = getFirstHopAddress(path);
     }

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

@@ -36,6 +36,7 @@
 import java.util.*;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicLong;
+import java.util.stream.Collectors;
 import org.scion.jpan.internal.*;
 import org.scion.jpan.proto.control_plane.SegmentLookupServiceGrpc;
 import org.scion.jpan.proto.daemon.Daemon;
@@ -605,4 +606,14 @@ InetAddress getExternalIP(InetSocketAddress firstHopAddress) {
       }
     }
   }
+
+  List<String> getBorderRouterStrings() {
+    if (daemonStub != null) {
+      return getInterfaces().values().stream()
+          .map(i -> i.getAddress().getAddress())
+          .collect(Collectors.toList());
+    } else {
+      return bootstrapper.getBorderRouterAddresses();
+    }
+  }
 }

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

@@ -14,6 +14,9 @@
 
 package org.scion.jpan;
 
+import java.net.InetAddress;
+import java.net.InetSocketAddress;
+import java.net.UnknownHostException;
 import org.scion.jpan.internal.PathRawParser;
 
 /** Scion utility functions. */
@@ -190,5 +193,15 @@ public static long extractAs(long isdAs) {
     return isdAs & MAX_AS;
   }
 
+  static InetSocketAddress parseInetSocketAddress(String addrStr) {
+    try {
+      int posColon = addrStr.indexOf(':');
+      InetAddress inetAddress = InetAddress.getByName(addrStr.substring(0, posColon));
+      return new InetSocketAddress(inetAddress, Integer.parseInt(addrStr.substring(posColon + 1)));
+    } catch (UnknownHostException e) {
+      throw new IllegalArgumentException(e);
+    }
+  }
+
   private ScionUtil() {}
 }

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

@@ -219,6 +219,11 @@ Scmp.TimedMessage sendEchoRequest(Scmp.EchoMessage request) throws IOException {
       writeLock().lock();
       try {
         Path path = request.getPath();
+        if (path.getRawPath().length == 0
+            && path.getFirstHopAddress().getAddress().isAnyLocalAddress()) {
+          throw new ScionException(
+              "Cannot ping service address in local AS: " + path.getFirstHopAddress());
+        }
         super.channel().connect(path.getFirstHopAddress());
         ByteBuffer buffer = getBufferSend(DEFAULT_BUFFER_SIZE);
         // EchoHeader = 8 + data

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

@@ -197,6 +197,14 @@ public String getBorderRouterAddress(int interfaceId) {
     throw new ScionRuntimeException("No router found with interface ID " + interfaceId);
   }
 
+  public List<String> getBorderRouterAddresses() {
+    List<String> result = new ArrayList<>();
+    for (BorderRouter br : borderRouters) {
+      result.add(br.internalAddress);
+    }
+    return result;
+  }
+
   public int getLocalMtu() {
     return this.localMtu;
   }

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

@@ -102,8 +102,13 @@ void echo() throws IOException {
   }
 
   @Test
-  void echo_localAS() throws IOException {
-    testEcho(this::getPathToLocalAS);
+  void echo_localAS_BR() throws IOException {
+    testEcho(this::getPathToLocalAS_BR);
+  }
+
+  @Test
+  void echo_localAS_SVC() {
+    assertThrows(ScionException.class, () -> testEcho(this::getPathToLocalAS_SVC));
   }
 
   private void testEcho(Supplier<Path> path) throws IOException {
@@ -194,8 +199,13 @@ void traceroute() throws IOException {
   }
 
   @Test
-  void traceroute_localAS() throws IOException {
-    testTraceroute(this::getPathToLocalAS, 0);
+  void traceroute_localAS_BR() throws IOException {
+    testTraceroute(this::getPathToLocalAS_BR, 0);
+  }
+
+  @Test
+  void traceroute_localAS_SVC() throws IOException {
+    testTraceroute(this::getPathToLocalAS_SVC, 0);
   }
 
   private void testTraceroute(Supplier<Path> path, int nHops) throws IOException {
@@ -307,10 +317,11 @@ private Path getPathTo112(InetAddress dstAddress) {
     return service.getPaths(dstIA, dstAddress, Constants.SCMP_PORT).get(0);
   }
 
-  private Path getPathToLocalAS() {
+  private Path getPathToLocalAS_BR() {
     ScionService service = Scion.defaultService();
     long dstIA = service.getLocalIsdAs();
     try {
+      // Border router address
       InetAddress addr = InetAddress.getByName(MockNetwork.BORDER_ROUTER_HOST);
       int port = MockNetwork.BORDER_ROUTER_PORT1;
       List<Path> paths = service.getPaths(dstIA, new InetSocketAddress(addr, port));
@@ -320,6 +331,20 @@ private Path getPathToLocalAS() {
     }
   }
 
+  private Path getPathToLocalAS_SVC() {
+    ScionService service = Scion.defaultService();
+    long dstIA = service.getLocalIsdAs();
+    try {
+      // Service address
+      InetAddress addr = InetAddress.getByAddress(new byte[] {0, 0, 0, 0});
+      int port = Constants.SCMP_PORT;
+      List<Path> paths = service.getPaths(dstIA, new InetSocketAddress(addr, port));
+      return paths.get(0);
+    } catch (UnknownHostException e) {
+      throw new RuntimeException(e);
+    }
+  }
+
   @Test
   void setUpScmpResponder_echo() throws IOException, InterruptedException {
     MockNetwork.startTiny();

src/test/java/org/scion/jpan/demo/ScmpEchoDemo.java

@@ -64,14 +64,13 @@ public ScmpEchoDemo(int localPort) {
   private static final Network network = Network.PRODUCTION;
 
   public static void main(String[] args) throws IOException {
-    ScionService service = Scion.defaultService();
     switch (network) {
       case JUNIT_MOCK:
         {
           DemoTopology.configureMock();
           MockDNS.install("1-ff00:0:112", "ip6-localhost", "::1");
           ScmpEchoDemo demo = new ScmpEchoDemo();
-          demo.runDemo(service.getPaths(DemoConstants.ia112, serviceIP).get(0));
+          demo.runDemo(Scion.defaultService().getPaths(DemoConstants.ia112, serviceIP).get(0));
           DemoTopology.shutDown();
           break;
         }
@@ -87,15 +86,18 @@ public static void main(String[] args) throws IOException {
           // System.setProperty(Constants.PROPERTY_DAEMON, DemoConstants.daemon1111_minimal);
 
           ScmpEchoDemo demo = new ScmpEchoDemo();
-          demo.runDemo(service.getPaths(DemoConstants.ia211, serviceIP).get(0));
-          // demo.runDemo(service.getPaths(DemoConstants.ia111, serviceIP).get(0));
-          // demo.runDemo(service.getPaths(DemoConstants.ia1111, serviceIP).get(0));
+          demo.runDemo(Scion.defaultService().getPaths(DemoConstants.ia211, serviceIP).get(0));
+          // Echo to local AS and on-path AS (111 is "on" the UP segment) is currently broken,
+          // see https://github.com/scionproto-contrib/jpan/issues/96
+          // demo.runDemo(Scion.defaultService().getPaths(DemoConstants.ia111, serviceIP).get(0));
+          // demo.runDemo(Scion.defaultService().getPaths(DemoConstants.ia1111, serviceIP).get(0));
           break;
         }
       case PRODUCTION:
         {
           // Local port must be 30041 for networks that expect a dispatcher
           ScmpEchoDemo demo = new ScmpEchoDemo(Constants.SCMP_PORT);
+          ScionService service = Scion.defaultService();
           demo.runDemo(service.lookupAndGetPath("ethz.ch", Constants.SCMP_PORT, null));
           demo.runDemo(service.getPaths(DemoConstants.iaOVGU, serviceIP).get(0));
           break;
@@ -160,10 +162,4 @@ private static void println(String msg) {
       System.out.println(msg);
     }
   }
-
-  private static InetSocketAddress toAddr(String addrString) throws UnknownHostException {
-    int posColon = addrString.indexOf(':');
-    InetAddress addr = InetAddress.getByName(addrString.substring(0, posColon));
-    return new InetSocketAddress(addr, Constants.SCMP_PORT);
-  }
 }

src/test/java/org/scion/jpan/demo/ScmpTracerouteDemo.java

@@ -72,6 +72,8 @@ public static void main(String[] args) throws IOException {
           System.setProperty(Constants.PROPERTY_DAEMON, DemoConstants.daemon1111_minimal);
           ScmpTracerouteDemo demo = new ScmpTracerouteDemo();
           demo.runDemo(DemoConstants.ia211);
+          demo.runDemo(DemoConstants.ia111);
+          demo.runDemo(DemoConstants.ia1111);
           break;
         }
       case PRODUCTION:

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

@@ -206,5 +206,21 @@ public void aS(Daemon.ASRequest req, StreamObserver<Daemon.ASResponse> responseO
       responseObserver.onNext(replyBuilder.build());
       responseObserver.onCompleted();
     }
+
+    @Override
+    public void interfaces(
+        Daemon.InterfacesRequest req, StreamObserver<Daemon.InterfacesResponse> responseObserver) {
+      callCount.incrementAndGet();
+      Daemon.InterfacesResponse.Builder replyBuilder = Daemon.InterfacesResponse.newBuilder();
+      int i = -1;
+      for (String br : borderRouters) {
+        Daemon.Interface.Builder ifBuilder = Daemon.Interface.newBuilder();
+        ifBuilder.setAddress(Daemon.Underlay.newBuilder().setAddress(br).build());
+        // Interface IDs are currently not supported
+        replyBuilder.putInterfaces(i--, ifBuilder.build());
+      }
+      responseObserver.onNext(replyBuilder.build());
+      responseObserver.onCompleted();
+    }
   }
 }