Add stacked interfaces to LinkProperties.

Bug: 8276725
Change-Id: I2f592d4c690e9af0459ae742ab16107a10d89353

2 files changed, 159 insertions, 6 deletions

diff --git a/core/java/android/net/LinkProperties.java b/core/java/android/net/LinkProperties.java
index 9292e5f..833549f 100644
--- a/core/java/android/net/LinkProperties.java
+++ b/core/java/android/net/LinkProperties.java
@@ -23,10 +23,13 @@ import android.text.TextUtils;
 import android.util.Log;
 
 import java.net.InetAddress;
+import java.net.Inet4Address;
+
 import java.net.UnknownHostException;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
+import java.util.Hashtable;
 
 /**
  * Describes the properties of a network link.
@@ -48,10 +51,15 @@ import java.util.Collections;
  * don't care which is used.  The gateways will be
  * selected based on the destination address and the
  * source address has no relavence.
+ *
+ * Links can also be stacked on top of each other.
+ * This can be used, for example, to represent a tunnel
+ * interface that runs on top of a physical interface.
+ *
  * @hide
  */
 public class LinkProperties implements Parcelable {
-
+    // The interface described by the network link.
     private String mIfaceName;
     private Collection<LinkAddress> mLinkAddresses = new ArrayList<LinkAddress>();
     private Collection<InetAddress> mDnses = new ArrayList<InetAddress>();
@@ -60,6 +68,11 @@ public class LinkProperties implements Parcelable {
     private ProxyProperties mHttpProxy;
     public boolean mLogMe;
 
+    // Stores the properties of links that are "stacked" above this link.
+    // Indexed by interface name to allow modification and to prevent duplicates being added.
+    private Hashtable<String, LinkProperties> mStackedLinks =
+        new Hashtable<String, LinkProperties>();
+
     public static class CompareResult<T> {
         public Collection<T> removed = new ArrayList<T>();
         public Collection<T> added = new ArrayList<T>();
@@ -90,6 +103,9 @@ public class LinkProperties implements Parcelable {
             for (RouteInfo r : source.getRoutes()) mRoutes.add(r);
             mHttpProxy = (source.getHttpProxy() == null)  ?
                     null : new ProxyProperties(source.getHttpProxy());
+            for (LinkProperties l: source.mStackedLinks.values()) {
+                addStackedLink(l);
+            }
         }
     }
 
@@ -165,10 +181,25 @@ public class LinkProperties implements Parcelable {
         }
     }
 
+    /**
+     * Returns all the routes on this link.
+     */
     public Collection<RouteInfo> getRoutes() {
         return Collections.unmodifiableCollection(mRoutes);
     }
 
+    /**
+     * Returns all the routes on this link and all the links stacked above it.
+     */
+    public Collection<RouteInfo> getAllRoutes() {
+        Collection<RouteInfo> routes = new ArrayList();
+        routes.addAll(mRoutes);
+        for (LinkProperties stacked: mStackedLinks.values()) {
+            routes.addAll(stacked.getAllRoutes());
+        }
+        return Collections.unmodifiableCollection(routes);
+    }
+
     public void setHttpProxy(ProxyProperties proxy) {
         mHttpProxy = proxy;
     }
@@ -176,6 +207,46 @@ public class LinkProperties implements Parcelable {
         return mHttpProxy;
     }
 
+    /**
+     * Adds a stacked link.
+     *
+     * If there is already a stacked link with the same interfacename as link,
+     * that link is replaced with link. Otherwise, link is added to the list
+     * of stacked links. If link is null, nothing changes.
+     *
+     * @param link The link to add.
+     */
+    public void addStackedLink(LinkProperties link) {
+        if (link != null && link.getInterfaceName() != null) {
+            mStackedLinks.put(link.getInterfaceName(), link);
+        }
+    }
+
+    /**
+     * Removes a stacked link.
+     *
+     * If there a stacked link with the same interfacename as link, it is
+     * removed. Otherwise, nothing changes.
+     *
+     * @param link The link to add.
+     */
+    public void removeStackedLink(LinkProperties link) {
+        if (link != null && link.getInterfaceName() != null) {
+            mStackedLinks.remove(link.getInterfaceName());
+        }
+    }
+
+    /**
+     * Returns all the links stacked on top of this link.
+     */
+    public Collection<LinkProperties> getStackedLinks() {
+        Collection<LinkProperties> stacked = new ArrayList<LinkProperties>();
+        for (LinkProperties link : mStackedLinks.values()) {
+          stacked.add(new LinkProperties(link));
+        }
+        return Collections.unmodifiableCollection(stacked);
+    }
+
     public void clear() {
         if (mLogMe) {
             Log.d("LinkProperties", "clear from " + mIfaceName);
@@ -190,6 +261,7 @@ public class LinkProperties implements Parcelable {
         mDomains = null;
         mRoutes.clear();
         mHttpProxy = null;
+        mStackedLinks.clear();
     }
 
     /**
@@ -219,7 +291,29 @@ public class LinkProperties implements Parcelable {
         routes += "] ";
         String proxy = (mHttpProxy == null ? "" : "HttpProxy: " + mHttpProxy.toString() + " ");
 
-        return ifaceName + linkAddresses + routes + dns + domainName + proxy;
+        String stacked = "";
+        if (mStackedLinks.values().size() > 0) {
+            stacked += " Stacked: [";
+            for (LinkProperties link: mStackedLinks.values()) {
+                stacked += " [" + link.toString() + " ],";
+            }
+            stacked += "] ";
+        }
+        return ifaceName + linkAddresses + routes + dns + domainName + proxy + stacked;
+    }
+
+    /**
+     * Returns true if this link has an IPv4 address.
+     *
+     * @return {@code true} if there is an IPv4 address, {@code false} otherwise.
+     */
+    public boolean hasIPv4Address() {
+        for (LinkAddress address : mLinkAddresses) {
+          if (address.getAddress() instanceof Inet4Address) {
+            return true;
+          }
+        }
+        return false;
     }
 
     /**
@@ -286,6 +380,26 @@ public class LinkProperties implements Parcelable {
                     getHttpProxy().equals(target.getHttpProxy());
     }
 
+    /**
+     * Compares this {@code LinkProperties} stacked links against the target
+     *
+     * @param target LinkProperties to compare.
+     * @return {@code true} if both are identical, {@code false} otherwise.
+     */
+    public boolean isIdenticalStackedLinks(LinkProperties target) {
+        if (!mStackedLinks.keys().equals(target.mStackedLinks.keys())) {
+            return false;
+        }
+        for (LinkProperties stacked : mStackedLinks.values()) {
+            // Hashtable values can never be null.
+            String iface = stacked.getInterfaceName();
+            if (!stacked.equals(target.mStackedLinks.get(iface))) {
+                return false;
+            }
+        }
+        return true;
+    }
+
     @Override
     /**
      * Compares this {@code LinkProperties} instance against the target
@@ -298,6 +412,10 @@ public class LinkProperties implements Parcelable {
      * 1. Duplicated elements. eg, (A, B, B) and (A, A, B) are equal.
      * 2. Worst case performance is O(n^2).
      *
+     * This method does not check that stacked interfaces are equal, because
+     * stacked interfaces are not so much a property of the link as a
+     * description of connections between links.
+     *
      * @param obj the object to be tested for equality.
      * @return {@code true} if both objects are equal, {@code false} otherwise.
      */
@@ -312,7 +430,8 @@ public class LinkProperties implements Parcelable {
                 isIdenticalAddresses(target) &&
                 isIdenticalDnses(target) &&
                 isIdenticalRoutes(target) &&
-                isIdenticalHttpProxy(target);
+                isIdenticalHttpProxy(target) &&
+                isIdenticalStackedLinks(target);
     }
 
     /**
@@ -394,10 +513,10 @@ public class LinkProperties implements Parcelable {
          */
         CompareResult<RouteInfo> result = new CompareResult<RouteInfo>();
 
-        result.removed = new ArrayList<RouteInfo>(mRoutes);
+        result.removed = getAllRoutes();
         result.added.clear();
         if (target != null) {
-            for (RouteInfo r : target.getRoutes()) {
+            for (RouteInfo r : target.getAllRoutes()) {
                 if (! result.removed.remove(r)) {
                     result.added.add(r);
                 }
@@ -419,7 +538,8 @@ public class LinkProperties implements Parcelable {
                 + mDnses.size() * 37
                 + ((null == mDomains) ? 0 : mDomains.hashCode())
                 + mRoutes.size() * 41
-                + ((null == mHttpProxy) ? 0 : mHttpProxy.hashCode()));
+                + ((null == mHttpProxy) ? 0 : mHttpProxy.hashCode())
+                + mStackedLinks.hashCode() * 47);
     }
 
     /**
@@ -449,6 +569,8 @@ public class LinkProperties implements Parcelable {
         } else {
             dest.writeByte((byte)0);
         }
+        ArrayList<LinkProperties> stackedLinks = new ArrayList(mStackedLinks.values());
+        dest.writeList(stackedLinks);
     }
 
     /**
@@ -481,6 +603,11 @@ public class LinkProperties implements Parcelable {
                 if (in.readByte() == 1) {
                     netProp.setHttpProxy((ProxyProperties)in.readParcelable(null));
                 }
+                ArrayList<LinkProperties> stackedLinks = new ArrayList<LinkProperties>();
+                in.readList(stackedLinks, LinkProperties.class.getClassLoader());
+                for (LinkProperties stackedLink: stackedLinks) {
+                    netProp.addStackedLink(stackedLink);
+                }
                 return netProp;
             }
 
diff --git a/core/tests/coretests/src/android/net/LinkPropertiesTest.java b/core/tests/coretests/src/android/net/LinkPropertiesTest.java
index fffaa00..c746e52 100644
--- a/core/tests/coretests/src/android/net/LinkPropertiesTest.java
+++ b/core/tests/coretests/src/android/net/LinkPropertiesTest.java
@@ -22,6 +22,7 @@ import android.test.suitebuilder.annotation.SmallTest;
 import junit.framework.TestCase;
 
 import java.net.InetAddress;
+import java.util.ArrayList;
 
 public class LinkPropertiesTest extends TestCase {
     private static String ADDRV4 = "75.208.6.1";
@@ -255,5 +256,30 @@ public class LinkPropertiesTest extends TestCase {
         assertAllRoutesHaveInterface("p2p0", lp2);
         assertEquals(3, lp.compareRoutes(lp2).added.size());
         assertEquals(3, lp.compareRoutes(lp2).removed.size());
+
+    @SmallTest
+    public void testStackedInterfaces() {
+        LinkProperties rmnet0 = new LinkProperties();
+        rmnet0.setInterfaceName("rmnet0");
+
+        LinkProperties clat4 = new LinkProperties();
+        clat4.setInterfaceName("clat4");
+
+        assertEquals(0, rmnet0.getStackedLinks().size());
+        rmnet0.addStackedLink(clat4);
+        assertEquals(1, rmnet0.getStackedLinks().size());
+        rmnet0.addStackedLink(clat4);
+        assertEquals(1, rmnet0.getStackedLinks().size());
+        assertEquals(0, clat4.getStackedLinks().size());
+
+        // Modify an item in the returned collection to see what happens.
+        for (LinkProperties link : rmnet0.getStackedLinks()) {
+            if (link.getInterfaceName().equals("clat4")) {
+               link.setInterfaceName("newname");
+            }
+        }
+        for (LinkProperties link : rmnet0.getStackedLinks()) {
+            assertFalse("newname".equals(link.getInterfaceName()));
+        }
     }
 }