Refactor BpfNetMaps and getChainEnabled

Address comments from aosp/2117045 and aosp/2131752
Rename USE_NETD to PRE_T
Rename getChainEnabled to isChainEnabled
Remove unnecessary parentheses
Fix comment

Bug: 217624062
Test: atest BpfNetMapsTest
Change-Id: Iaff8c9fc5f74de3fe41a7fb010355b1742fbce90
diff --git a/framework/src/android/net/ConnectivityManager.java b/framework/src/android/net/ConnectivityManager.java
index 02083ff..eeedfd1 100644
--- a/framework/src/android/net/ConnectivityManager.java
+++ b/framework/src/android/net/ConnectivityManager.java
@@ -5922,7 +5922,7 @@
     }
 
     /**
-     * Get the specified firewall chain status.
+     * Get the specified firewall chain's status.
      *
      * @param chain target chain.
      * @return {@code true} if chain is enabled, {@code false} if chain is disabled.
diff --git a/service/src/com/android/server/BpfNetMaps.java b/service/src/com/android/server/BpfNetMaps.java
index 3ee3ea1..81e9e3a 100644
--- a/service/src/com/android/server/BpfNetMaps.java
+++ b/service/src/com/android/server/BpfNetMaps.java
@@ -53,7 +53,7 @@
     private static final String TAG = "BpfNetMaps";
     private final INetd mNetd;
     // Use legacy netd for releases before T.
-    private static final boolean USE_NETD = !SdkLevel.isAtLeastT();
+    private static final boolean PRE_T = !SdkLevel.isAtLeastT();
     private static boolean sInitialized = false;
 
     // Lock for sConfigurationMap entry for UID_RULES_CONFIGURATION_KEY.
@@ -112,7 +112,7 @@
      */
     private static synchronized void ensureInitialized() {
         if (sInitialized) return;
-        if (!USE_NETD) {
+        if (!PRE_T) {
             System.loadLibrary("service-connectivity");
             native_init();
             initialize(new Dependencies());
@@ -143,7 +143,7 @@
     public BpfNetMaps() {
         this(null);
 
-        if (USE_NETD) throw new IllegalArgumentException("BpfNetMaps need to use netd before T");
+        if (PRE_T) throw new IllegalArgumentException("BpfNetMaps need to use netd before T");
     }
 
     public BpfNetMaps(final INetd netd) {
@@ -169,8 +169,8 @@
         }
     }
 
-    private void throwIfUseNetd(final String msg) {
-        if (USE_NETD) {
+    private void throwIfPreT(final String msg) {
+        if (PRE_T) {
             throw new UnsupportedOperationException(msg);
         }
     }
@@ -233,7 +233,7 @@
      *                                  cause of the failure.
      */
     public void setChildChain(final int childChain, final boolean enable) {
-        throwIfUseNetd("setChildChain is not available on pre-T devices");
+        throwIfPreT("setChildChain is not available on pre-T devices");
 
         final long match = getMatchByFirewallChain(childChain);
         try {
@@ -244,7 +244,7 @@
                             "Unable to get firewall chain status: sConfigurationMap does not have"
                                     + " entry for UID_RULES_CONFIGURATION_KEY");
                 }
-                final long newConfig = enable ? (config.val | match) : (config.val & (~match));
+                final long newConfig = enable ? (config.val | match) : (config.val & ~match);
                 sConfigurationMap.updateEntry(UID_RULES_CONFIGURATION_KEY, new U32(newConfig));
             }
         } catch (ErrnoException e) {
@@ -254,7 +254,7 @@
     }
 
     /**
-     * Get the specified firewall chain status.
+     * Get the specified firewall chain's status.
      *
      * @param childChain target chain
      * @return {@code true} if chain is enabled, {@code false} if chain is not enabled.
@@ -262,8 +262,8 @@
      * @throws ServiceSpecificException in case of failure, with an error code indicating the
      *                                  cause of the failure.
      */
-    public boolean getChainEnabled(final int childChain) {
-        throwIfUseNetd("getChainEnabled is not available on pre-T devices");
+    public boolean isChainEnabled(final int childChain) {
+        throwIfPreT("isChainEnabled is not available on pre-T devices");
 
         final long match = getMatchByFirewallChain(childChain);
         try {
@@ -334,7 +334,7 @@
      *                                  cause of the failure.
      */
     public void addUidInterfaceRules(final String ifName, final int[] uids) throws RemoteException {
-        if (USE_NETD) {
+        if (PRE_T) {
             mNetd.firewallAddUidInterfaceRules(ifName, uids);
             return;
         }
@@ -354,7 +354,7 @@
      *                                  cause of the failure.
      */
     public void removeUidInterfaceRules(final int[] uids) throws RemoteException {
-        if (USE_NETD) {
+        if (PRE_T) {
             mNetd.firewallRemoveUidInterfaceRules(uids);
             return;
         }
@@ -397,7 +397,7 @@
      * @throws RemoteException when netd has crashed.
      */
     public void setNetPermForUids(final int permissions, final int[] uids) throws RemoteException {
-        if (USE_NETD) {
+        if (PRE_T) {
             mNetd.trafficSetNetPermForUids(permissions, uids);
             return;
         }
@@ -413,7 +413,7 @@
      */
     public void dump(final FileDescriptor fd, boolean verbose)
             throws IOException, ServiceSpecificException {
-        if (USE_NETD) {
+        if (PRE_T) {
             throw new ServiceSpecificException(
                     EOPNOTSUPP, "dumpsys connectivity trafficcontroller dump not available on pre-T"
                     + " devices, use dumpsys netd trafficcontroller instead.");
diff --git a/service/src/com/android/server/ConnectivityService.java b/service/src/com/android/server/ConnectivityService.java
index 6568654..b210bb3 100644
--- a/service/src/com/android/server/ConnectivityService.java
+++ b/service/src/com/android/server/ConnectivityService.java
@@ -11387,7 +11387,7 @@
     public boolean getFirewallChainEnabled(final int chain) {
         enforceNetworkStackOrSettingsPermission();
 
-        return mBpfNetMaps.getChainEnabled(chain);
+        return mBpfNetMaps.isChainEnabled(chain);
     }
 
     @Override
diff --git a/tests/unit/java/com/android/server/BpfNetMapsTest.java b/tests/unit/java/com/android/server/BpfNetMapsTest.java
index 99e7ecc..634ec9c 100644
--- a/tests/unit/java/com/android/server/BpfNetMapsTest.java
+++ b/tests/unit/java/com/android/server/BpfNetMapsTest.java
@@ -116,7 +116,7 @@
         verify(mNetd).trafficSetNetPermForUids(PERMISSION_INTERNET, TEST_UIDS);
     }
 
-    private void doTestGetChainEnabled(final List<Integer> enableChains) throws Exception {
+    private void doTestIsChainEnabled(final List<Integer> enableChains) throws Exception {
         long match = 0;
         for (final int chain: enableChains) {
             match |= mBpfNetMaps.getMatchByFirewallChain(chain);
@@ -126,67 +126,67 @@
         for (final int chain: FIREWALL_CHAINS) {
             final String testCase = "EnabledChains: " + enableChains + " CheckedChain: " + chain;
             if (enableChains.contains(chain)) {
-                assertTrue("Expected getChainEnabled returns True, " + testCase,
-                        mBpfNetMaps.getChainEnabled(chain));
+                assertTrue("Expected isChainEnabled returns True, " + testCase,
+                        mBpfNetMaps.isChainEnabled(chain));
             } else {
-                assertFalse("Expected getChainEnabled returns False, " + testCase,
-                        mBpfNetMaps.getChainEnabled(chain));
+                assertFalse("Expected isChainEnabled returns False, " + testCase,
+                        mBpfNetMaps.isChainEnabled(chain));
             }
         }
     }
 
-    private void doTestGetChainEnabled(final int enableChain) throws Exception {
-        doTestGetChainEnabled(List.of(enableChain));
+    private void doTestIsChainEnabled(final int enableChain) throws Exception {
+        doTestIsChainEnabled(List.of(enableChain));
     }
 
     @Test
     @IgnoreUpTo(Build.VERSION_CODES.S_V2)
-    public void testGetChainEnabled() throws Exception {
-        doTestGetChainEnabled(FIREWALL_CHAIN_DOZABLE);
-        doTestGetChainEnabled(FIREWALL_CHAIN_STANDBY);
-        doTestGetChainEnabled(FIREWALL_CHAIN_POWERSAVE);
-        doTestGetChainEnabled(FIREWALL_CHAIN_RESTRICTED);
-        doTestGetChainEnabled(FIREWALL_CHAIN_LOW_POWER_STANDBY);
-        doTestGetChainEnabled(FIREWALL_CHAIN_OEM_DENY_1);
-        doTestGetChainEnabled(FIREWALL_CHAIN_OEM_DENY_2);
-        doTestGetChainEnabled(FIREWALL_CHAIN_OEM_DENY_3);
+    public void testIsChainEnabled() throws Exception {
+        doTestIsChainEnabled(FIREWALL_CHAIN_DOZABLE);
+        doTestIsChainEnabled(FIREWALL_CHAIN_STANDBY);
+        doTestIsChainEnabled(FIREWALL_CHAIN_POWERSAVE);
+        doTestIsChainEnabled(FIREWALL_CHAIN_RESTRICTED);
+        doTestIsChainEnabled(FIREWALL_CHAIN_LOW_POWER_STANDBY);
+        doTestIsChainEnabled(FIREWALL_CHAIN_OEM_DENY_1);
+        doTestIsChainEnabled(FIREWALL_CHAIN_OEM_DENY_2);
+        doTestIsChainEnabled(FIREWALL_CHAIN_OEM_DENY_3);
     }
 
     @Test
     @IgnoreUpTo(Build.VERSION_CODES.S_V2)
-    public void testGetChainEnabledMultipleChainEnabled() throws Exception {
-        doTestGetChainEnabled(List.of(
+    public void testIsChainEnabledMultipleChainEnabled() throws Exception {
+        doTestIsChainEnabled(List.of(
                 FIREWALL_CHAIN_DOZABLE,
                 FIREWALL_CHAIN_STANDBY));
-        doTestGetChainEnabled(List.of(
+        doTestIsChainEnabled(List.of(
                 FIREWALL_CHAIN_DOZABLE,
                 FIREWALL_CHAIN_STANDBY,
                 FIREWALL_CHAIN_POWERSAVE,
                 FIREWALL_CHAIN_RESTRICTED));
-        doTestGetChainEnabled(FIREWALL_CHAINS);
+        doTestIsChainEnabled(FIREWALL_CHAINS);
     }
 
     @Test
     @IgnoreUpTo(Build.VERSION_CODES.S_V2)
-    public void testGetChainEnabledInvalidChain() {
+    public void testIsChainEnabledInvalidChain() {
         final Class<ServiceSpecificException> expected = ServiceSpecificException.class;
-        assertThrows(expected, () -> mBpfNetMaps.getChainEnabled(-1 /* childChain */));
-        assertThrows(expected, () -> mBpfNetMaps.getChainEnabled(1000 /* childChain */));
+        assertThrows(expected, () -> mBpfNetMaps.isChainEnabled(-1 /* childChain */));
+        assertThrows(expected, () -> mBpfNetMaps.isChainEnabled(1000 /* childChain */));
     }
 
     @Test
     @IgnoreUpTo(Build.VERSION_CODES.S_V2)
-    public void testGetChainEnabledMissingConfiguration() {
+    public void testIsChainEnabledMissingConfiguration() {
         // sConfigurationMap does not have entry for UID_RULES_CONFIGURATION_KEY
         assertThrows(ServiceSpecificException.class,
-                () -> mBpfNetMaps.getChainEnabled(FIREWALL_CHAIN_DOZABLE));
+                () -> mBpfNetMaps.isChainEnabled(FIREWALL_CHAIN_DOZABLE));
     }
 
     @Test
     @IgnoreAfter(Build.VERSION_CODES.S_V2)
-    public void testGetChainEnabledBeforeT() {
+    public void testIsChainEnabledBeforeT() {
         assertThrows(UnsupportedOperationException.class,
-                () -> mBpfNetMaps.getChainEnabled(FIREWALL_CHAIN_DOZABLE));
+                () -> mBpfNetMaps.isChainEnabled(FIREWALL_CHAIN_DOZABLE));
     }
 
     private void doTestSetChildChain(final List<Integer> testChains) throws Exception {