1 files changed, 338 insertions, 0 deletions
diff --git a/Tethering/tests/privileged/src/android/net/ip/DadProxyTest.java b/Tethering/tests/privileged/src/android/net/ip/DadProxyTest.java
new file mode 100644
index 0000000000..747d3e8030
--- /dev/null
+++ b/Tethering/tests/privileged/src/android/net/ip/DadProxyTest.java
@@ -0,0 +1,338 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.net.ip;
+
+import static android.system.OsConstants.IPPROTO_ICMPV6;
+import static android.system.OsConstants.IPPROTO_TCP;
+
+import static com.android.internal.util.BitUtils.uint16;
+
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertTrue;
+
+import android.app.Instrumentation;
+import android.content.Context;
+import android.net.INetd;
+import android.net.InetAddresses;
+import android.net.MacAddress;
+import android.net.TestNetworkInterface;
+import android.net.TestNetworkManager;
+import android.net.util.InterfaceParams;
+import android.net.util.IpUtils;
+import android.net.util.TetheringUtils;
+import android.os.Handler;
+import android.os.HandlerThread;
+import android.os.IBinder;
+import android.os.Looper;
+import android.system.ErrnoException;
+import android.system.Os;
+
+import androidx.test.InstrumentationRegistry;
+import androidx.test.filters.SmallTest;
+import androidx.test.runner.AndroidJUnit4;
+
+import com.android.testutils.TapPacketReader;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.BeforeClass;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.MockitoAnnotations;
+
+import java.io.FileDescriptor;
+import java.nio.ByteBuffer;
+import java.util.concurrent.atomic.AtomicReference;
+
+@RunWith(AndroidJUnit4.class)
+@SmallTest
+public class DadProxyTest {
+    private static final int DATA_BUFFER_LEN = 4096;
+    private static final int PACKET_TIMEOUT_MS = 5_000;
+
+    // TODO: make NetworkStackConstants accessible to this test and use the constant from there.
+    private static final int ETHER_SRC_ADDR_OFFSET = 6;
+
+    private DadProxy mProxy;
+    TestNetworkInterface mUpstreamTestIface, mTetheredTestIface;
+    private InterfaceParams mUpstreamParams, mTetheredParams;
+    private HandlerThread mHandlerThread;
+    private Handler mHandler;
+    private TapPacketReader mUpstreamPacketReader, mTetheredPacketReader;
+    private FileDescriptor mUpstreamTapFd, mTetheredTapFd;
+
+    private static INetd sNetd;
+
+    @BeforeClass
+    public static void setupOnce() {
+        System.loadLibrary("tetherutilsjni");
+
+        final Instrumentation inst = InstrumentationRegistry.getInstrumentation();
+        final IBinder netdIBinder =
+                (IBinder) inst.getContext().getSystemService(Context.NETD_SERVICE);
+        sNetd = INetd.Stub.asInterface(netdIBinder);
+    }
+
+    @Before
+    public void setUp() throws Exception {
+        MockitoAnnotations.initMocks(this);
+
+        mHandlerThread = new HandlerThread(getClass().getSimpleName());
+        mHandlerThread.start();
+        mHandler = new Handler(mHandlerThread.getLooper());
+
+        setupTapInterfaces();
+
+        // Looper must be prepared here since AndroidJUnitRunner runs tests on separate threads.
+        if (Looper.myLooper() == null) Looper.prepare();
+
+        DadProxy mProxy = setupProxy();
+    }
+
+    @After
+    public void tearDown() throws Exception {
+        if (mHandlerThread != null) {
+            mHandler.post(mUpstreamPacketReader::stop); // Also closes the socket
+            mHandler.post(mTetheredPacketReader::stop); // Also closes the socket
+            mUpstreamTapFd = null;
+            mTetheredTapFd = null;
+            mHandlerThread.quitSafely();
+        }
+
+        if (mTetheredParams != null) {
+            sNetd.networkRemoveInterface(INetd.LOCAL_NET_ID, mTetheredParams.name);
+        }
+        if (mUpstreamParams != null) {
+            sNetd.networkRemoveInterface(INetd.LOCAL_NET_ID, mUpstreamParams.name);
+        }
+
+        if (mUpstreamTestIface != null) {
+            try {
+                Os.close(mUpstreamTestIface.getFileDescriptor().getFileDescriptor());
+            } catch (ErrnoException e) { }
+        }
+
+        if (mTetheredTestIface != null) {
+            try {
+                Os.close(mTetheredTestIface.getFileDescriptor().getFileDescriptor());
+            } catch (ErrnoException e) { }
+        }
+    }
+
+    private TestNetworkInterface setupTapInterface() {
+        final Instrumentation inst = InstrumentationRegistry.getInstrumentation();
+        AtomicReference<TestNetworkInterface> iface = new AtomicReference<>();
+
+        inst.getUiAutomation().adoptShellPermissionIdentity();
+        try {
+            final TestNetworkManager tnm = (TestNetworkManager) inst.getContext().getSystemService(
+                    Context.TEST_NETWORK_SERVICE);
+            iface.set(tnm.createTapInterface());
+        } finally {
+            inst.getUiAutomation().dropShellPermissionIdentity();
+        }
+
+        return iface.get();
+    }
+
+    private void setupTapInterfaces() {
+        // Create upstream test iface.
+        mUpstreamTestIface = setupTapInterface();
+        mUpstreamParams = InterfaceParams.getByName(mUpstreamTestIface.getInterfaceName());
+        assertNotNull(mUpstreamParams);
+        mUpstreamTapFd = mUpstreamTestIface.getFileDescriptor().getFileDescriptor();
+        mUpstreamPacketReader = new TapPacketReader(mHandler, mUpstreamTapFd,
+                                                    DATA_BUFFER_LEN);
+        mHandler.post(mUpstreamPacketReader::start);
+
+        // Create tethered test iface.
+        mTetheredTestIface = setupTapInterface();
+        mTetheredParams = InterfaceParams.getByName(mTetheredTestIface.getInterfaceName());
+        assertNotNull(mTetheredParams);
+        mTetheredTapFd = mTetheredTestIface.getFileDescriptor().getFileDescriptor();
+        mTetheredPacketReader = new TapPacketReader(mHandler, mTetheredTapFd,
+                                                    DATA_BUFFER_LEN);
+        mHandler.post(mTetheredPacketReader::start);
+    }
+
+    private static final int IPV6_HEADER_LEN = 40;
+    private static final int ETH_HEADER_LEN = 14;
+    private static final int ICMPV6_NA_NS_LEN = 24;
+    private static final int LL_TARGET_OPTION_LEN = 8;
+    private static final int ICMPV6_CHECKSUM_OFFSET = 2;
+    private static final int ETHER_TYPE_IPV6 = 0x86dd;
+
+    // TODO: move the IpUtils code to frameworks/lib/net and link it statically.
+    private static int checksumFold(int sum) {
+        while (sum > 0xffff) {
+            sum = (sum >> 16) + (sum & 0xffff);
+        }
+        return sum;
+    }
+
+    // TODO: move the IpUtils code to frameworks/lib/net and link it statically.
+    private static short checksumAdjust(short checksum, short oldWord, short newWord) {
+        checksum = (short) ~checksum;
+        int tempSum = checksumFold(uint16(checksum) + uint16(newWord) + 0xffff - uint16(oldWord));
+        return (short) ~tempSum;
+    }
+
+    // TODO: move the IpUtils code to frameworks/lib/net and link it statically.
+    private static short icmpv6Checksum(ByteBuffer buf, int ipOffset, int transportOffset,
+            int transportLen) {
+        // The ICMPv6 checksum is the same as the TCP checksum, except the pseudo-header uses
+        // 58 (ICMPv6) instead of 6 (TCP). Calculate the TCP checksum, and then do an incremental
+        // checksum adjustment  for the change in the next header byte.
+        short checksum = IpUtils.tcpChecksum(buf, ipOffset, transportOffset, transportLen);
+        return checksumAdjust(checksum, (short) IPPROTO_TCP, (short) IPPROTO_ICMPV6);
+    }
+
+    private static ByteBuffer createDadPacket(int type) {
+        // Refer to buildArpPacket()
+        int icmpLen = ICMPV6_NA_NS_LEN
+                + (type == NeighborPacketForwarder.ICMPV6_NEIGHBOR_ADVERTISEMENT
+                ? LL_TARGET_OPTION_LEN : 0);
+        final ByteBuffer buf = ByteBuffer.allocate(icmpLen + IPV6_HEADER_LEN + ETH_HEADER_LEN);
+
+        // Ethernet header.
+        final MacAddress srcMac = MacAddress.fromString("33:33:ff:66:77:88");
+        buf.put(srcMac.toByteArray());
+        final MacAddress dstMac = MacAddress.fromString("01:02:03:04:05:06");
+        buf.put(dstMac.toByteArray());
+        buf.putShort((short) ETHER_TYPE_IPV6);
+
+        // IPv6 header
+        byte[] version = {(byte) 0x60, 0x00, 0x00, 0x00};
+        buf.put(version);                                           // Version
+        buf.putShort((byte) icmpLen);                               // Length
+        buf.put((byte) IPPROTO_ICMPV6);                             // Next header
+        buf.put((byte) 0xff);                                       // Hop limit
+
+        final byte[] target =
+            InetAddresses.parseNumericAddress("fe80::1122:3344:5566:7788").getAddress();
+        final byte[] src;
+        final byte[] dst;
+        if (type == NeighborPacketForwarder.ICMPV6_NEIGHBOR_SOLICITATION) {
+            src = InetAddresses.parseNumericAddress("::").getAddress();
+            dst = InetAddresses.parseNumericAddress("ff02::1:ff66:7788").getAddress();
+        } else {
+            src = target;
+            dst = TetheringUtils.ALL_NODES;
+        }
+        buf.put(src);
+        buf.put(dst);
+
+        // ICMPv6 Header
+        buf.put((byte) type);                                       // Type
+        buf.put((byte) 0x00);                                       // Code
+        buf.putShort((short) 0);                                    // Checksum
+        buf.putInt(0);                                              // Reserved
+        buf.put(target);
+
+        if (type == NeighborPacketForwarder.ICMPV6_NEIGHBOR_ADVERTISEMENT) {
+            //NA packet has LL target address
+            //ICMPv6 Option
+            buf.put((byte) 0x02);                                   // Type
+            buf.put((byte) 0x01);                                   // Length
+            byte[] ll_target = MacAddress.fromString("01:02:03:04:05:06").toByteArray();
+            buf.put(ll_target);
+        }
+
+        // Populate checksum field
+        final int transportOffset = ETH_HEADER_LEN + IPV6_HEADER_LEN;
+        final short checksum = icmpv6Checksum(buf, ETH_HEADER_LEN, transportOffset, icmpLen);
+        buf.putShort(transportOffset + ICMPV6_CHECKSUM_OFFSET, checksum);
+
+        buf.flip();
+        return buf;
+    }
+
+    private DadProxy setupProxy() throws Exception {
+        DadProxy proxy = new DadProxy(mHandler, mTetheredParams);
+        mHandler.post(() -> proxy.setUpstreamIface(mUpstreamParams));
+
+        // Upstream iface is added to local network to simplify test case.
+        // Otherwise the test needs to create and destroy a network for the upstream iface.
+        sNetd.networkAddInterface(INetd.LOCAL_NET_ID, mUpstreamParams.name);
+        sNetd.networkAddInterface(INetd.LOCAL_NET_ID, mTetheredParams.name);
+
+        return proxy;
+    }
+
+    // TODO: change to assert.
+    private boolean waitForPacket(ByteBuffer packet, TapPacketReader reader) {
+        byte[] p;
+
+        while ((p = reader.popPacket(PACKET_TIMEOUT_MS)) != null) {
+            final ByteBuffer buffer = ByteBuffer.wrap(p);
+
+            if (buffer.compareTo(packet) == 0) return true;
+        }
+        return false;
+    }
+
+    private void updateDstMac(ByteBuffer buf, MacAddress mac) {
+        buf.put(mac.toByteArray());
+        buf.rewind();
+    }
+    private void updateSrcMac(ByteBuffer buf, InterfaceParams ifaceParams) {
+        buf.position(ETHER_SRC_ADDR_OFFSET);
+        buf.put(ifaceParams.macAddr.toByteArray());
+        buf.rewind();
+    }
+
+    @Test
+    public void testNaForwardingFromUpstreamToTether() throws Exception {
+        ByteBuffer na = createDadPacket(NeighborPacketForwarder.ICMPV6_NEIGHBOR_ADVERTISEMENT);
+
+        mUpstreamPacketReader.sendResponse(na);
+        updateDstMac(na, MacAddress.fromString("33:33:00:00:00:01"));
+        updateSrcMac(na, mTetheredParams);
+        assertTrue(waitForPacket(na, mTetheredPacketReader));
+    }
+
+    @Test
+    // TODO: remove test once DAD works in both directions.
+    public void testNaForwardingFromTetherToUpstream() throws Exception {
+        ByteBuffer na = createDadPacket(NeighborPacketForwarder.ICMPV6_NEIGHBOR_ADVERTISEMENT);
+
+        mTetheredPacketReader.sendResponse(na);
+        updateDstMac(na, MacAddress.fromString("33:33:00:00:00:01"));
+        updateSrcMac(na, mTetheredParams);
+        assertFalse(waitForPacket(na, mUpstreamPacketReader));
+    }
+
+    @Test
+    public void testNsForwardingFromTetherToUpstream() throws Exception {
+        ByteBuffer ns = createDadPacket(NeighborPacketForwarder.ICMPV6_NEIGHBOR_SOLICITATION);
+
+        mTetheredPacketReader.sendResponse(ns);
+        updateSrcMac(ns, mUpstreamParams);
+        assertTrue(waitForPacket(ns, mUpstreamPacketReader));
+    }
+
+    @Test
+    // TODO: remove test once DAD works in both directions.
+    public void testNsForwardingFromUpstreamToTether() throws Exception {
+        ByteBuffer ns = createDadPacket(NeighborPacketForwarder.ICMPV6_NEIGHBOR_SOLICITATION);
+
+        mUpstreamPacketReader.sendResponse(ns);
+        updateSrcMac(ns, mUpstreamParams);
+        assertFalse(waitForPacket(ns, mTetheredPacketReader));
+    }
+}