BpfCoordinator: avoid attach/deatach ipv6 program on 464xlat interface

464xlat interface v4-* doesn't have IPv6 address. IPv6 program should
not be attached/deatached on v4-* interface.

Bug: 241106456
Test: atest BpfCoordinatorTest
Test: manual test

Use IPv6-only wifi to test because there is no IPv6-only live
cellular environment here.

1. Patch TetheringInterfaceUtils.allowIpv6Tethering to allow WIFI.
2. Connect to IPv6-only wifi Google-Guest.
3. Enable USB tethering.
4. Check that v4-wlan0 doesn't have IPv6 program.

$ adb shell tc filter show dev wlan0 ingress;
filter protocol ipv6 pref 2 bpf chain 0
filter protocol ipv6 pref 2 bpf chain 0 handle 0x1 prog_offload_schedcls_tether_downstream6_ether:[*fsobj] direct-action not_in_hw id 2 tag 7d9be9d02d02e8d8
filter protocol ip pref 3 bpf chain 0
filter protocol ip pref 3 bpf chain 0 handle 0x1 prog_offload_schedcls_tether_downstream4_ether:[*fsobj] direct-action not_in_hw id 8 tag 434b3ecac7968bb3
filter protocol ipv6 pref 4 bpf chain 0
filter protocol ipv6 pref 4 bpf chain 0 handle 0x1 prog_clatd_schedcls_ingress6_clat_ether:[*fsobj] direct-action not_in_hw id 24 tag 06763574e0e1f984

$ adb shell tc filter show dev v4-wlan0 ingress;
filter protocol ip pref 3 bpf chain 0
filter protocol ip pref 3 bpf chain 0 handle 0x1 prog_offload_schedcls_tether_downstream4_rawip:[*fsobj] direct-action not_in_hw id 6 tag 9e6e587e0c6cf0bc

$ adb shell tc filter show dev v4-wlan0 egress;
filter protocol ip pref 4 bpf chain 0
filter protocol ip pref 4 bpf chain 0 handle 0x1 prog_clatd_schedcls_egress4_clat_rawip:[*fsobj] direct-action not_in_hw id 27 tag 9158397a2869247e

$ adb shell tc filter show dev ncm0 ingress;
filter protocol ipv6 pref 2 bpf chain 0
filter protocol ipv6 pref 2 bpf chain 0 handle 0x1 prog_offload_schedcls_tether_upstream6_ether:[*fsobj] direct-action not_in_hw id 3 tag 5f70a4f42dffe899
filter protocol ip pref 3 bpf chain 0
filter protocol ip pref 3 bpf chain 0 handle 0x1 prog_offload_schedcls_tether_upstream4_ether:[*fsobj] direct-action not_in_hw id 9 tag 26f324113d54c30a

Change-Id: Ic1c1cfc7646b4d4004856850b66428e4651d42ab

Tethering/apishim/30/com/android/networkstack/tethering/apishim/api30/BpfCoordinatorShimImpl.java

@@ -168,13 +168,13 @@ public class BpfCoordinatorShimImpl
     }
 
     @Override
-    public boolean attachProgram(String iface, boolean downstream) {
+    public boolean attachProgram(String iface, boolean downstream, boolean ipv4) {
         /* no op */
         return true;
     }
 
     @Override
-    public boolean detachProgram(String iface) {
+    public boolean detachProgram(String iface, boolean ipv4) {
         /* no op */
         return true;
     }

Tethering/apishim/31/com/android/networkstack/tethering/apishim/api31/BpfCoordinatorShimImpl.java

@@ -425,11 +425,11 @@ public class BpfCoordinatorShimImpl
     }
 
     @Override
-    public boolean attachProgram(String iface, boolean downstream) {
+    public boolean attachProgram(String iface, boolean downstream, boolean ipv4) {
         if (!isInitialized()) return false;
 
         try {
-            BpfUtils.attachProgram(iface, downstream);
+            BpfUtils.attachProgram(iface, downstream, ipv4);
         } catch (IOException e) {
             mLog.e("Could not attach program: " + e);
             return false;
@@ -438,11 +438,11 @@ public class BpfCoordinatorShimImpl
     }
 
     @Override
-    public boolean detachProgram(String iface) {
+    public boolean detachProgram(String iface, boolean ipv4) {
         if (!isInitialized()) return false;
 
         try {
-            BpfUtils.detachProgram(iface);
+            BpfUtils.detachProgram(iface, ipv4);
         } catch (IOException e) {
             mLog.e("Could not detach program: " + e);
             return false;

Tethering/apishim/common/com/android/networkstack/tethering/apishim/common/BpfCoordinatorShim.java

@@ -172,16 +172,24 @@ public abstract class BpfCoordinatorShim {
     /**
      * Attach BPF program.
      *
+     * @param iface the interface name to attach program.
+     * @param downstream indicate the datapath. true if downstream, false if upstream.
+     * @param ipv4 indicate the protocol family. true if ipv4, false if ipv6.
+     *
      * TODO: consider using InterfaceParams to replace interface name.
      */
-    public abstract boolean attachProgram(@NonNull String iface, boolean downstream);
+    public abstract boolean attachProgram(@NonNull String iface, boolean downstream,
+            boolean ipv4);
 
     /**
      * Detach BPF program.
      *
+     * @param iface the interface name to detach program.
+     * @param ipv4 indicate the protocol family. true if ipv4, false if ipv6.
+     *
      * TODO: consider using InterfaceParams to replace interface name.
      */
-    public abstract boolean detachProgram(@NonNull String iface);
+    public abstract boolean detachProgram(@NonNull String iface, boolean ipv4);
 
     /**
      * Add interface index mapping.

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

@@ -895,6 +895,28 @@ public class BpfCoordinator {
         }
     }
 
+    private boolean is464XlatInterface(@NonNull String ifaceName) {
+        return ifaceName.startsWith("v4-");
+    }
+
+    private void maybeAttachProgramImpl(@NonNull String iface, boolean downstream) {
+        mBpfCoordinatorShim.attachProgram(iface, downstream, true /* ipv4 */);
+
+        // Ignore 464xlat interface because it is IPv4 only.
+        if (!is464XlatInterface(iface)) {
+            mBpfCoordinatorShim.attachProgram(iface, downstream, false /* ipv4 */);
+        }
+    }
+
+    private void maybeDetachProgramImpl(@NonNull String iface) {
+        mBpfCoordinatorShim.detachProgram(iface, true /* ipv4 */);
+
+        // Ignore 464xlat interface because it is IPv4 only.
+        if (!is464XlatInterface(iface)) {
+            mBpfCoordinatorShim.detachProgram(iface, false /* ipv4 */);
+        }
+    }
+
     /**
      * Attach BPF program
      *
@@ -913,11 +935,11 @@ public class BpfCoordinator {
         // Ex: IPv6 only interface has two forwarding pair, iface and v4-iface, on the
         // same downstream.
         if (firstUpstreamForThisDownstream) {
-            mBpfCoordinatorShim.attachProgram(intIface, UPSTREAM);
+            maybeAttachProgramImpl(intIface, UPSTREAM);
         }
         // Attach if the upstream is the first time to be used in a forwarding pair.
         if (firstDownstreamForThisUpstream) {
-            mBpfCoordinatorShim.attachProgram(extIface, DOWNSTREAM);
+            maybeAttachProgramImpl(extIface, DOWNSTREAM);
         }
     }
 
@@ -929,11 +951,11 @@ public class BpfCoordinator {
 
         // Detaching program may fail because the interface has been removed already.
         if (!isAnyForwardingPairOnDownstream(intIface)) {
-            mBpfCoordinatorShim.detachProgram(intIface);
+            maybeDetachProgramImpl(intIface);
         }
         // Detach if no more forwarding pair is using the upstream.
         if (!isAnyForwardingPairOnUpstream(extIface)) {
-            mBpfCoordinatorShim.detachProgram(extIface);
+            maybeDetachProgramImpl(extIface);
         }
     }
 

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

@@ -74,7 +74,7 @@ public class BpfUtils {
      *
      * TODO: use interface index to replace interface name.
      */
-    public static void attachProgram(@NonNull String iface, boolean downstream)
+    public static void attachProgram(@NonNull String iface, boolean downstream, boolean ipv4)
             throws IOException {
         final InterfaceParams params = InterfaceParams.getByName(iface);
         if (params == null) {
@@ -88,16 +88,7 @@ public class BpfUtils {
             throw new IOException("isEthernet(" + params.index + "[" + iface + "]) failure: " + e);
         }
 
-        try {
+        if (ipv4) {
-            // tc filter add dev .. ingress prio 1 protocol ipv6 bpf object-pinned /sys/fs/bpf/...
-            // direct-action
-            TcUtils.tcFilterAddDevBpf(params.index, INGRESS, PRIO_TETHER6, (short) ETH_P_IPV6,
-                    makeProgPath(downstream, 6, ether));
-        } catch (IOException e) {
-            throw new IOException("tc filter add dev (" + params.index + "[" + iface
-                    + "]) ingress prio PRIO_TETHER6 protocol ipv6 failure: " + e);
-        }
-
             try {
                 // tc filter add dev .. ingress prio 2 protocol ip bpf object-pinned /sys/fs/bpf/...
                 // direct-action
@@ -107,6 +98,17 @@ public class BpfUtils {
                 throw new IOException("tc filter add dev (" + params.index + "[" + iface
                         + "]) ingress prio PRIO_TETHER4 protocol ip failure: " + e);
             }
+        } else {
+            try {
+                // tc filter add dev .. ingress prio 1 protocol ipv6 bpf object-pinned
+                // /sys/fs/bpf/... direct-action
+                TcUtils.tcFilterAddDevBpf(params.index, INGRESS, PRIO_TETHER6, (short) ETH_P_IPV6,
+                        makeProgPath(downstream, 6, ether));
+            } catch (IOException e) {
+                throw new IOException("tc filter add dev (" + params.index + "[" + iface
+                        + "]) ingress prio PRIO_TETHER6 protocol ipv6 failure: " + e);
+            }
+        }
     }
 
     /**
@@ -114,20 +116,13 @@ public class BpfUtils {
      *
      * TODO: use interface index to replace interface name.
      */
-    public static void detachProgram(@NonNull String iface) throws IOException {
+    public static void detachProgram(@NonNull String iface, boolean ipv4) throws IOException {
         final InterfaceParams params = InterfaceParams.getByName(iface);
         if (params == null) {
             throw new IOException("Fail to get interface params for interface " + iface);
         }
 
-        try {
+        if (ipv4) {
-            // tc filter del dev .. ingress prio 1 protocol ipv6
-            TcUtils.tcFilterDelDev(params.index, INGRESS, PRIO_TETHER6, (short) ETH_P_IPV6);
-        } catch (IOException e) {
-            throw new IOException("tc filter del dev (" + params.index + "[" + iface
-                    + "]) ingress prio PRIO_TETHER6 protocol ipv6 failure: " + e);
-        }
-
             try {
                 // tc filter del dev .. ingress prio 2 protocol ip
                 TcUtils.tcFilterDelDev(params.index, INGRESS, PRIO_TETHER4, (short) ETH_P_IP);
@@ -135,5 +130,14 @@ public class BpfUtils {
                 throw new IOException("tc filter del dev (" + params.index + "[" + iface
                         + "]) ingress prio PRIO_TETHER4 protocol ip failure: " + e);
             }
+        } else {
+            try {
+                // tc filter del dev .. ingress prio 1 protocol ipv6
+                TcUtils.tcFilterDelDev(params.index, INGRESS, PRIO_TETHER6, (short) ETH_P_IPV6);
+            } catch (IOException e) {
+                throw new IOException("tc filter del dev (" + params.index + "[" + iface
+                        + "]) ingress prio PRIO_TETHER6 protocol ipv6 failure: " + e);
+            }
+        }
     }
 }

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

@@ -59,6 +59,7 @@ import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertTrue;
 import static org.junit.Assert.fail;
 import static org.mockito.Matchers.any;
+import static org.mockito.Matchers.anyBoolean;
 import static org.mockito.Matchers.anyInt;
 import static org.mockito.Matchers.anyLong;
 import static org.mockito.Matchers.anyString;
@@ -141,6 +142,9 @@ public class BpfCoordinatorTest {
     @Rule
     public final DevSdkIgnoreRule mIgnoreRule = new DevSdkIgnoreRule();
 
+    private static final boolean IPV4 = true;
+    private static final boolean IPV6 = false;
+
     private static final int TEST_NET_ID = 24;
     private static final int TEST_NET_ID2 = 25;
 
@@ -1286,8 +1290,10 @@ public class BpfCoordinatorTest {
             // [1] Add the forwarding pair <wlan1, rmnet_data0>. Expect that attach both wlan1 and
             // rmnet_data0.
             coordinator.maybeAttachProgram(intIface1, extIface1);
-            ExtendedMockito.verify(() -> BpfUtils.attachProgram(extIface1, DOWNSTREAM));
+            ExtendedMockito.verify(() -> BpfUtils.attachProgram(extIface1, DOWNSTREAM, IPV4));
-            ExtendedMockito.verify(() -> BpfUtils.attachProgram(intIface1, UPSTREAM));
+            ExtendedMockito.verify(() -> BpfUtils.attachProgram(extIface1, DOWNSTREAM, IPV6));
+            ExtendedMockito.verify(() -> BpfUtils.attachProgram(intIface1, UPSTREAM, IPV4));
+            ExtendedMockito.verify(() -> BpfUtils.attachProgram(intIface1, UPSTREAM, IPV6));
             ExtendedMockito.verifyNoMoreInteractions(mockMarkerBpfUtils);
             ExtendedMockito.clearInvocations(mockMarkerBpfUtils);
 
@@ -1298,42 +1304,49 @@ public class BpfCoordinatorTest {
 
             // [3] Add the forwarding pair <rndis0, rmnet_data0>. Expect that attach rndis0 only.
             coordinator.maybeAttachProgram(intIface2, extIface1);
-            ExtendedMockito.verify(() -> BpfUtils.attachProgram(intIface2, UPSTREAM));
+            ExtendedMockito.verify(() -> BpfUtils.attachProgram(intIface2, UPSTREAM, IPV4));
+            ExtendedMockito.verify(() -> BpfUtils.attachProgram(intIface2, UPSTREAM, IPV6));
             ExtendedMockito.verifyNoMoreInteractions(mockMarkerBpfUtils);
             ExtendedMockito.clearInvocations(mockMarkerBpfUtils);
 
             // [4] Add the forwarding pair <rndis0, v4-rmnet_data0>. Expect that attach
-            // v4-rmnet_data0 only.
+            // v4-rmnet_data0 IPv4 program only.
             coordinator.maybeAttachProgram(intIface2, extIface2);
-            ExtendedMockito.verify(() -> BpfUtils.attachProgram(extIface2, DOWNSTREAM));
+            ExtendedMockito.verify(() -> BpfUtils.attachProgram(extIface2, DOWNSTREAM, IPV4));
+            ExtendedMockito.verify(() -> BpfUtils.attachProgram(extIface2, DOWNSTREAM, IPV6),
+                    never());
             ExtendedMockito.verifyNoMoreInteractions(mockMarkerBpfUtils);
             ExtendedMockito.clearInvocations(mockMarkerBpfUtils);
 
             // [5] Remove the forwarding pair <rndis0, v4-rmnet_data0>. Expect detach
-            // v4-rmnet_data0 only.
+            // v4-rmnet_data0 IPv4 program only.
             coordinator.maybeDetachProgram(intIface2, extIface2);
-            ExtendedMockito.verify(() -> BpfUtils.detachProgram(extIface2));
+            ExtendedMockito.verify(() -> BpfUtils.detachProgram(extIface2, IPV4));
+            ExtendedMockito.verify(() -> BpfUtils.detachProgram(extIface2, IPV6), never());
             ExtendedMockito.verifyNoMoreInteractions(mockMarkerBpfUtils);
             ExtendedMockito.clearInvocations(mockMarkerBpfUtils);
 
             // [6] Remove the forwarding pair <rndis0, rmnet_data0>. Expect detach rndis0 only.
             coordinator.maybeDetachProgram(intIface2, extIface1);
-            ExtendedMockito.verify(() -> BpfUtils.detachProgram(intIface2));
+            ExtendedMockito.verify(() -> BpfUtils.detachProgram(intIface2, IPV4));
+            ExtendedMockito.verify(() -> BpfUtils.detachProgram(intIface2, IPV6));
             ExtendedMockito.verifyNoMoreInteractions(mockMarkerBpfUtils);
             ExtendedMockito.clearInvocations(mockMarkerBpfUtils);
 
             // [7] Remove the forwarding pair <wlan1, rmnet_data0>. Expect that detach both wlan1
             // and rmnet_data0.
             coordinator.maybeDetachProgram(intIface1, extIface1);
-            ExtendedMockito.verify(() -> BpfUtils.detachProgram(extIface1));
+            ExtendedMockito.verify(() -> BpfUtils.detachProgram(extIface1, IPV4));
-            ExtendedMockito.verify(() -> BpfUtils.detachProgram(intIface1));
+            ExtendedMockito.verify(() -> BpfUtils.detachProgram(extIface1, IPV6));
+            ExtendedMockito.verify(() -> BpfUtils.detachProgram(intIface1, IPV4));
+            ExtendedMockito.verify(() -> BpfUtils.detachProgram(intIface1, IPV6));
             ExtendedMockito.verifyNoMoreInteractions(mockMarkerBpfUtils);
             ExtendedMockito.clearInvocations(mockMarkerBpfUtils);
 
             // [8] Skip attaching if upstream is virtual interface.
             coordinator.maybeAttachProgram(intIface1, virtualIface);
-            ExtendedMockito.verify(() -> BpfUtils.attachProgram(extIface1, DOWNSTREAM), never());
+            ExtendedMockito.verify(() ->
-            ExtendedMockito.verify(() -> BpfUtils.attachProgram(intIface1, UPSTREAM), never());
+                    BpfUtils.attachProgram(anyString(), anyBoolean(), anyBoolean()), never());
             ExtendedMockito.verifyNoMoreInteractions(mockMarkerBpfUtils);
             ExtendedMockito.clearInvocations(mockMarkerBpfUtils);