Move error count BPF map initialization into class Dependencies

The preparation for testing BpfCoordinator#dump().
Used to wrap error count BPF map access to avoid SYS_SECCOMP on some
test device. Ex: cuttlefish.
https://android-build.googleplex.com/builds/tests/view?invocationId=I01200010101524265&testResultId=TR03228338750686157

Bug: 255466740
Test: atest BpfCoordinatorTest

Change-Id: Id4405b70bc6d500b35943b4f81b88e7515fff3b0

Tethering/src/com/android/networkstack/tethering/BpfCoordinator.java

@@ -403,6 +403,18 @@ public class BpfCoordinator {
                 return null;
             }
         }
+
+        /** Get error BPF map. */
+        @Nullable public IBpfMap<S32, S32> getBpfErrorMap() {
+            if (!isAtLeastS()) return null;
+            try {
+                return new BpfMap<>(TETHER_ERROR_MAP_PATH,
+                    BpfMap.BPF_F_RDONLY, S32.class, S32.class);
+            } catch (ErrnoException e) {
+                Log.e(TAG, "Cannot create error map: " + e);
+                return null;
+            }
+        }
     }
 
     @VisibleForTesting
@@ -1287,13 +1299,15 @@ public class BpfCoordinator {
     }
 
     private void dumpCounters(@NonNull IndentingPrintWriter pw) {
-        if (!mDeps.isAtLeastS()) {
+        try (IBpfMap<S32, S32> map = mDeps.getBpfErrorMap()) {
-            pw.println("No counter support");
+            if (map == null) {
-            return;
+                pw.println("No error counter support");
-        }
+                return;
-        try (IBpfMap<S32, S32> map = new BpfMap<>(TETHER_ERROR_MAP_PATH, BpfMap.BPF_F_RDONLY,
+            }
-                S32.class, S32.class)) {
+            if (map.isEmpty()) {
-
+                pw.println("<empty>");
+                return;
+            }
             map.forEach((k, v) -> {
                 String counterName;
                 try {
@@ -1307,7 +1321,7 @@ public class BpfCoordinator {
                 if (v.val > 0) pw.println(String.format("%s: %d", counterName, v.val));
             });
         } catch (ErrnoException | IOException e) {
-            pw.println("Error dumping counter map: " + e);
+            pw.println("Error dumping error counter map: " + e);
         }
     }
 

Tethering/tests/unit/src/android/net/ip/IpServerTest.java

@@ -99,6 +99,7 @@ import com.android.net.module.util.BpfMap;
 import com.android.net.module.util.InterfaceParams;
 import com.android.net.module.util.NetworkStackConstants;
 import com.android.net.module.util.SharedLog;
+import com.android.net.module.util.Struct.S32;
 import com.android.net.module.util.bpf.Tether4Key;
 import com.android.net.module.util.bpf.Tether4Value;
 import com.android.net.module.util.bpf.TetherStatsKey;
@@ -197,6 +198,7 @@ public class IpServerTest {
     @Mock private BpfMap<TetherStatsKey, TetherStatsValue> mBpfStatsMap;
     @Mock private BpfMap<TetherLimitKey, TetherLimitValue> mBpfLimitMap;
     @Mock private BpfMap<TetherDevKey, TetherDevValue> mBpfDevMap;
+    @Mock private BpfMap<S32, S32> mBpfErrorMap;
 
     @Captor private ArgumentCaptor<DhcpServingParamsParcel> mDhcpParamsCaptor;
 
@@ -360,6 +362,11 @@ public class IpServerTest {
                     public BpfMap<TetherDevKey, TetherDevValue> getBpfDevMap() {
                         return mBpfDevMap;
                     }
+
+                    @Nullable
+                    public BpfMap<S32, S32> getBpfErrorMap() {
+                        return mBpfErrorMap;
+                    }
                 };
         mBpfCoordinator = spy(new BpfCoordinator(mBpfDeps));
 

Tethering/tests/unit/src/com/android/networkstack/tethering/BpfCoordinatorTest.java

@@ -99,6 +99,7 @@ import com.android.net.module.util.IBpfMap;
 import com.android.net.module.util.InterfaceParams;
 import com.android.net.module.util.NetworkStackConstants;
 import com.android.net.module.util.SharedLog;
+import com.android.net.module.util.Struct.S32;
 import com.android.net.module.util.bpf.Tether4Key;
 import com.android.net.module.util.bpf.Tether4Value;
 import com.android.net.module.util.bpf.TetherStatsKey;
@@ -365,6 +366,7 @@ public class BpfCoordinatorTest {
     @Mock private IBpfMap<TetherDownstream6Key, Tether6Value> mBpfDownstream6Map;
     @Mock private IBpfMap<TetherUpstream6Key, Tether6Value> mBpfUpstream6Map;
     @Mock private IBpfMap<TetherDevKey, TetherDevValue> mBpfDevMap;
+    @Mock private IBpfMap<S32, S32> mBpfErrorMap;
 
     // Late init since methods must be called by the thread that created this object.
     private TestableNetworkStatsProviderCbBinder mTetherStatsProviderCb;
@@ -457,6 +459,11 @@ public class BpfCoordinatorTest {
                     public IBpfMap<TetherDevKey, TetherDevValue> getBpfDevMap() {
                         return mBpfDevMap;
                     }
+
+                    @Nullable
+                    public IBpfMap<S32, S32> getBpfErrorMap() {
+                        return mBpfErrorMap;
+                    }
             });
 
     @Before public void setUp() {