Merge "Pick an upstream interface with valid IP config" into honeycomb

core/java/android/net/InterfaceConfiguration.java

@@ -39,14 +39,36 @@ public class InterfaceConfiguration implements Parcelable {
     public String toString() {
         StringBuffer str = new StringBuffer();
 
-        str.append("ipddress "); str.append(addr.toString());
-        str.append(" netmask "); str.append(mask.toString());
+        str.append("ipddress ");
+        str.append((addr != null) ? addr.toString() : "NULL");
+        str.append(" netmask ");
+        str.append((mask != null) ? mask.toString() : "NULL");
         str.append(" flags ").append(interfaceFlags);
         str.append(" hwaddr ").append(hwAddr);
 
         return str.toString();
     }
 
+    /**
+     * This function determines if the interface is up and has a valid IP
+     * configuration (IP address has a non zero octet).
+     *
+     * Note: It is supposed to be quick and hence should not initiate
+     * any network activity
+     */
+    public boolean isActive() {
+        try {
+            if(interfaceFlags.contains("up")) {
+                for (byte b : addr.getAddress()) {
+                    if (b != 0) return true;
+                }
+            }
+        } catch (NullPointerException e) {
+            return false;
+        }
+        return false;
+    }
+
     /** Implement the Parcelable interface {@hide} */
     public int describeContents() {
         return 0;

services/java/com/android/server/connectivity/Tethering.java

@@ -1233,18 +1233,18 @@ public class Tethering extends INetworkManagementEventObserver.Stub {
                 for (String iface : ifaces) {
                     for (String regex : mUpstreamIfaceRegexs) {
                         if (iface.matches(regex)) {
-                            // verify it is up!
+                            // verify it is active
                             InterfaceConfiguration ifcg = null;
                             try {
                                 ifcg = service.getInterfaceConfig(iface);
+                                if (ifcg.isActive()) {
+                                    return iface;
+                                }
                             } catch (Exception e) {
                                 Log.e(TAG, "Error getting iface config :" + e);
                                 // ignore - try next
                                 continue;
                             }
-                            if (ifcg.interfaceFlags.contains("up")) {
-                                return iface;
-                            }
                         }
                     }
                 }