Add tethering IPv4 UDP forwarding test
This is a preparation for testing IPv4 BPF offload.
- Add an ARP responder.
- Add a basic UDP forwarding test.
Test: atest EthernetTetheringTest
Change-Id: I720a5a2c4b97493eb6a5570cecd73dfc1eabf5cd
diff --git a/Tethering/tests/integration/src/android/net/EthernetTetheringTest.java b/Tethering/tests/integration/src/android/net/EthernetTetheringTest.java
index 15f07f2..8bf1a2b 100644
--- a/Tethering/tests/integration/src/android/net/EthernetTetheringTest.java
+++ b/Tethering/tests/integration/src/android/net/EthernetTetheringTest.java
@@ -25,9 +25,14 @@
import static android.net.TetheringManager.CONNECTIVITY_SCOPE_GLOBAL;
import static android.net.TetheringManager.CONNECTIVITY_SCOPE_LOCAL;
import static android.net.TetheringManager.TETHERING_ETHERNET;
+import static android.net.TetheringTester.RemoteResponder;
import static android.system.OsConstants.IPPROTO_ICMPV6;
+import static android.system.OsConstants.IPPROTO_IP;
+import static android.system.OsConstants.IPPROTO_UDP;
import static com.android.net.module.util.ConnectivityUtils.isIPv6ULA;
+import static com.android.net.module.util.HexDump.dumpHexString;
+import static com.android.net.module.util.NetworkStackConstants.ETHER_TYPE_IPV4;
import static com.android.net.module.util.NetworkStackConstants.ETHER_TYPE_IPV6;
import static com.android.net.module.util.NetworkStackConstants.ICMPV6_ROUTER_ADVERTISEMENT;
import static com.android.testutils.TestNetworkTrackerKt.initTestNetwork;
@@ -47,20 +52,26 @@
import android.net.TetheringManager.StartTetheringCallback;
import android.net.TetheringManager.TetheringEventCallback;
import android.net.TetheringManager.TetheringRequest;
+import android.net.TetheringTester.TetheredDevice;
import android.os.Handler;
import android.os.HandlerThread;
import android.os.SystemClock;
import android.os.SystemProperties;
import android.util.Log;
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
import androidx.test.InstrumentationRegistry;
import androidx.test.filters.MediumTest;
import androidx.test.runner.AndroidJUnit4;
+import com.android.net.module.util.PacketBuilder;
import com.android.net.module.util.Struct;
import com.android.net.module.util.structs.EthernetHeader;
import com.android.net.module.util.structs.Icmpv6Header;
+import com.android.net.module.util.structs.Ipv4Header;
import com.android.net.module.util.structs.Ipv6Header;
+import com.android.net.module.util.structs.UdpHeader;
import com.android.testutils.HandlerUtils;
import com.android.testutils.TapPacketReader;
import com.android.testutils.TestNetworkTracker;
@@ -71,6 +82,7 @@
import org.junit.runner.RunWith;
import java.io.FileDescriptor;
+import java.net.Inet4Address;
import java.net.InetAddress;
import java.net.InterfaceAddress;
import java.net.NetworkInterface;
@@ -92,10 +104,13 @@
private static final String TAG = EthernetTetheringTest.class.getSimpleName();
private static final int TIMEOUT_MS = 5000;
+ private static final int TETHER_REACHABILITY_ATTEMPTS = 20;
private static final LinkAddress TEST_IP4_ADDR = new LinkAddress("10.0.0.1/8");
private static final LinkAddress TEST_IP6_ADDR = new LinkAddress("2001:db8:1::101/64");
private static final InetAddress TEST_IP4_DNS = parseNumericAddress("8.8.8.8");
private static final InetAddress TEST_IP6_DNS = parseNumericAddress("2001:db8:1::888");
+ private static final ByteBuffer TEST_REACHABILITY_PAYLOAD =
+ ByteBuffer.wrap(new byte[] { (byte) 0x55, (byte) 0xaa });
private final Context mContext = InstrumentationRegistry.getContext();
private final EthernetManager mEm = mContext.getSystemService(EthernetManager.class);
@@ -105,6 +120,7 @@
private HandlerThread mHandlerThread;
private Handler mHandler;
private TapPacketReader mDownstreamReader;
+ private TapPacketReader mUpstreamReader;
private TetheredInterfaceRequester mTetheredInterfaceRequester;
private MyTetheringEventCallback mTetheringEventCallback;
@@ -140,6 +156,11 @@
mUpstreamTracker.teardown();
mUpstreamTracker = null;
}
+ if (mUpstreamReader != null) {
+ TapPacketReader reader = mUpstreamReader;
+ mHandler.post(() -> reader.stop());
+ mUpstreamReader = null;
+ }
mTm.stopTethering(TETHERING_ETHERNET);
if (mTetheringEventCallback != null) {
@@ -706,6 +727,168 @@
// TODO: do basic forwarding test here.
}
+ // Test network topology:
+ //
+ // public network (rawip) private network
+ // | UE |
+ // +------------+ V +------------+------------+ V +------------+
+ // | Sever +---------+ Upstream | Downstream +---------+ Client |
+ // +------------+ +------------+------------+ +------------+
+ // remote ip public ip private ip
+ // 8.8.8.8:443 <Upstream ip>:9876 <TetheredDevice ip>:9876
+ //
+ private static final Inet4Address REMOTE_IP4_ADDR =
+ (Inet4Address) parseNumericAddress("8.8.8.8");
+ // Used by public port and private port. Assume port 9876 has not been used yet before the
+ // testing that public port and private port are the same in the testing. Note that NAT port
+ // forwarding could be different between private port and public port.
+ private static final short LOCAL_PORT = 9876;
+ private static final short REMOTE_PORT = 433;
+ private static final byte TYPE_OF_SERVICE = 0;
+ private static final short ID = 27149;
+ private static final short ID2 = 27150;
+ private static final short FLAGS_AND_FRAGMENT_OFFSET = (short) 0x4000; // flags=DF, offset=0
+ private static final byte TIME_TO_LIVE = (byte) 0x40;
+ private static final ByteBuffer PAYLOAD =
+ ByteBuffer.wrap(new byte[] { (byte) 0x12, (byte) 0x34 });
+ private static final ByteBuffer PAYLOAD2 =
+ ByteBuffer.wrap(new byte[] { (byte) 0x56, (byte) 0x78 });
+
+ private boolean isExpectedUdpPacket(@NonNull final byte[] rawPacket, boolean hasEther,
+ @NonNull final ByteBuffer payload) {
+ final ByteBuffer buf = ByteBuffer.wrap(rawPacket);
+
+ if (hasEther) {
+ final EthernetHeader etherHeader = Struct.parse(EthernetHeader.class, buf);
+ if (etherHeader == null) return false;
+ }
+
+ final Ipv4Header ipv4Header = Struct.parse(Ipv4Header.class, buf);
+ if (ipv4Header == null) return false;
+
+ final UdpHeader udpHeader = Struct.parse(UdpHeader.class, buf);
+ if (udpHeader == null) return false;
+
+ if (buf.remaining() != payload.limit()) return false;
+
+ return Arrays.equals(Arrays.copyOfRange(buf.array(), buf.position(), buf.limit()),
+ payload.array());
+ }
+
+ @NonNull
+ private ByteBuffer buildUdpv4Packet(@Nullable final MacAddress srcMac,
+ @Nullable final MacAddress dstMac, short id,
+ @NonNull final Inet4Address srcIp, @NonNull final Inet4Address dstIp,
+ short srcPort, short dstPort, @Nullable final ByteBuffer payload)
+ throws Exception {
+ final boolean hasEther = (srcMac != null && dstMac != null);
+ final int payloadLen = (payload == null) ? 0 : payload.limit();
+ final ByteBuffer buffer = PacketBuilder.allocate(hasEther, IPPROTO_IP, IPPROTO_UDP,
+ payloadLen);
+ final PacketBuilder packetBuilder = new PacketBuilder(buffer);
+
+ if (hasEther) packetBuilder.writeL2Header(srcMac, dstMac, (short) ETHER_TYPE_IPV4);
+ packetBuilder.writeIpv4Header(TYPE_OF_SERVICE, ID, FLAGS_AND_FRAGMENT_OFFSET,
+ TIME_TO_LIVE, (byte) IPPROTO_UDP, srcIp, dstIp);
+ packetBuilder.writeUdpHeader(srcPort, dstPort);
+ if (payload != null) {
+ buffer.put(payload);
+ // in case data might be reused by caller, restore the position and
+ // limit of bytebuffer.
+ payload.clear();
+ }
+
+ return packetBuilder.finalizePacket();
+ }
+
+ @NonNull
+ private ByteBuffer buildUdpv4Packet(short id, @NonNull final Inet4Address srcIp,
+ @NonNull final Inet4Address dstIp, short srcPort, short dstPort,
+ @Nullable final ByteBuffer payload) throws Exception {
+ return buildUdpv4Packet(null /* srcMac */, null /* dstMac */, id, srcIp, dstIp, srcPort,
+ dstPort, payload);
+ }
+
+ // TODO: remove this verification once upstream connected notification race is fixed.
+ // See #runUdp4Test.
+ private boolean isIpv4TetherConnectivityVerified(TetheringTester tester,
+ RemoteResponder remote, TetheredDevice tethered) throws Exception {
+ final ByteBuffer probePacket = buildUdpv4Packet(tethered.macAddr,
+ tethered.routerMacAddr, ID, tethered.ipv4Addr /* srcIp */,
+ REMOTE_IP4_ADDR /* dstIp */, LOCAL_PORT /* srcPort */, REMOTE_PORT /*dstPort */,
+ TEST_REACHABILITY_PAYLOAD);
+
+ // Send a UDP packet from client and check the packet can be found on upstream interface.
+ for (int i = 0; i < TETHER_REACHABILITY_ATTEMPTS; i++) {
+ tester.sendPacket(probePacket);
+ byte[] expectedPacket = remote.getNextMatchedPacket(p -> {
+ Log.d(TAG, "Packet in upstream: " + dumpHexString(p));
+ return isExpectedUdpPacket(p, false /* hasEther */, TEST_REACHABILITY_PAYLOAD);
+ });
+ if (expectedPacket != null) return true;
+ }
+ return false;
+ }
+
+ private void runUdp4Test(TetheringTester tester, RemoteResponder remote) throws Exception {
+ final TetheredDevice tethered = tester.createTetheredDevice(MacAddress.fromString(
+ "1:2:3:4:5:6"));
+
+ // TODO: remove the connectivity verification for upstream connected notification race.
+ // Because async upstream connected notification can't guarantee the tethering routing is
+ // ready to use. Need to test tethering connectivity before testing.
+ // For short term plan, consider using IPv6 RA to get MAC address because the prefix comes
+ // from upstream. That can guarantee that the routing is ready. Long term plan is that
+ // refactors upstream connected notification from async to sync.
+ assertTrue(isIpv4TetherConnectivityVerified(tester, remote, tethered));
+
+ // Send a UDP packet in original direction.
+ final ByteBuffer originalPacket = buildUdpv4Packet(tethered.macAddr,
+ tethered.routerMacAddr, ID, tethered.ipv4Addr /* srcIp */,
+ REMOTE_IP4_ADDR /* dstIp */, LOCAL_PORT /* srcPort */, REMOTE_PORT /*dstPort */,
+ PAYLOAD /* payload */);
+ tester.verifyUpload(remote, originalPacket, p -> {
+ Log.d(TAG, "Packet in upstream: " + dumpHexString(p));
+ return isExpectedUdpPacket(p, false /* hasEther */, PAYLOAD);
+ });
+
+ // Send a UDP packet in reply direction.
+ final Inet4Address publicIp4Addr = (Inet4Address) TEST_IP4_ADDR.getAddress();
+ final ByteBuffer replyPacket = buildUdpv4Packet(ID2, REMOTE_IP4_ADDR /* srcIp */,
+ publicIp4Addr /* dstIp */, REMOTE_PORT /* srcPort */, LOCAL_PORT /*dstPort */,
+ PAYLOAD2 /* payload */);
+ remote.verifyDownload(tester, replyPacket, p -> {
+ Log.d(TAG, "Packet in downstream: " + dumpHexString(p));
+ return isExpectedUdpPacket(p, true/* hasEther */, PAYLOAD2);
+ });
+ }
+
+ @Test
+ public void testUdpV4() throws Exception {
+ assumeFalse(mEm.isAvailable());
+
+ // MyTetheringEventCallback currently only support await first available upstream. Tethering
+ // may select internet network as upstream if test network is not available and not be
+ // preferred yet. Create test upstream network before enable tethering.
+ mUpstreamTracker = createTestUpstream(toList(TEST_IP4_ADDR));
+
+ mDownstreamIface = createTestInterface();
+ mEm.setIncludeTestInterfaces(true);
+
+ final String iface = mTetheredInterfaceRequester.getInterface();
+ assertEquals("TetheredInterfaceCallback for unexpected interface",
+ mDownstreamIface.getInterfaceName(), iface);
+
+ mTetheringEventCallback = enableEthernetTethering(mDownstreamIface.getInterfaceName());
+ assertEquals("onUpstreamChanged for unexpected network", mUpstreamTracker.getNetwork(),
+ mTetheringEventCallback.awaitFirstUpstreamConnected());
+
+ mDownstreamReader = makePacketReader(mDownstreamIface);
+ mUpstreamReader = makePacketReader(mUpstreamTracker.getTestIface());
+
+ runUdp4Test(new TetheringTester(mDownstreamReader), new RemoteResponder(mUpstreamReader));
+ }
+
private <T> List<T> toList(T... array) {
return Arrays.asList(array);
}
diff --git a/Tethering/tests/integration/src/android/net/TetheringTester.java b/Tethering/tests/integration/src/android/net/TetheringTester.java
index d61bbb3..d24661a 100644
--- a/Tethering/tests/integration/src/android/net/TetheringTester.java
+++ b/Tethering/tests/integration/src/android/net/TetheringTester.java
@@ -16,6 +16,12 @@
package android.net;
+import static com.android.net.module.util.NetworkStackConstants.ARP_REPLY;
+import static com.android.net.module.util.NetworkStackConstants.ARP_REQUEST;
+import static com.android.net.module.util.NetworkStackConstants.ETHER_ADDR_LEN;
+import static com.android.net.module.util.NetworkStackConstants.ETHER_BROADCAST;
+
+import static org.junit.Assert.assertNotNull;
import static org.junit.Assert.fail;
import android.net.dhcp.DhcpAckPacket;
@@ -24,6 +30,9 @@
import android.util.ArrayMap;
import android.util.Log;
+import androidx.annotation.Nullable;
+
+import com.android.networkstack.arp.ArpPacket;
import com.android.testutils.TapPacketReader;
import java.net.Inet4Address;
@@ -72,15 +81,17 @@
}
public class TetheredDevice {
- private final MacAddress mMacAddr;
-
- public final Inet4Address mIpv4Addr;
+ public final MacAddress macAddr;
+ public final MacAddress routerMacAddr;
+ public final Inet4Address ipv4Addr;
private TetheredDevice(MacAddress mac) throws Exception {
- mMacAddr = mac;
+ macAddr = mac;
- DhcpResults dhcpResults = runDhcp(mMacAddr.toByteArray());
- mIpv4Addr = (Inet4Address) dhcpResults.ipAddress.getAddress();
+ DhcpResults dhcpResults = runDhcp(macAddr.toByteArray());
+ ipv4Addr = (Inet4Address) dhcpResults.ipAddress.getAddress();
+ routerMacAddr = getRouterMacAddressFromArp(ipv4Addr, macAddr,
+ dhcpResults.serverAddress);
}
}
@@ -146,12 +157,84 @@
DhcpPacket.decodeFullPacket(packet, packet.length, DhcpPacket.ENCAP_L2);
}
+ @Nullable
+ private ArpPacket parseArpPacket(final byte[] packet) {
+ try {
+ return ArpPacket.parseArpPacket(packet, packet.length);
+ } catch (ArpPacket.ParseException e) {
+ return null;
+ }
+ }
+
+ private void maybeReplyArp(byte[] packet) {
+ ByteBuffer buf = ByteBuffer.wrap(packet);
+
+ final ArpPacket arpPacket = parseArpPacket(packet);
+ if (arpPacket == null || arpPacket.opCode != ARP_REQUEST) return;
+
+ for (int i = 0; i < mTetheredDevices.size(); i++) {
+ TetheredDevice tethered = mTetheredDevices.valueAt(i);
+ if (!arpPacket.targetIp.equals(tethered.ipv4Addr)) continue;
+
+ final ByteBuffer arpReply = ArpPacket.buildArpPacket(
+ arpPacket.senderHwAddress.toByteArray() /* dst */,
+ tethered.macAddr.toByteArray() /* srcMac */,
+ arpPacket.senderIp.getAddress() /* target IP */,
+ arpPacket.senderHwAddress.toByteArray() /* target HW address */,
+ tethered.ipv4Addr.getAddress() /* sender IP */,
+ (short) ARP_REPLY);
+ try {
+ sendPacket(arpReply);
+ } catch (Exception e) {
+ fail("Failed to reply ARP for " + tethered.ipv4Addr);
+ }
+ return;
+ }
+ }
+
+ private MacAddress getRouterMacAddressFromArp(final Inet4Address tetherIp,
+ final MacAddress tetherMac, final Inet4Address routerIp) throws Exception {
+ final ByteBuffer arpProbe = ArpPacket.buildArpPacket(ETHER_BROADCAST /* dst */,
+ tetherMac.toByteArray() /* srcMac */, routerIp.getAddress() /* target IP */,
+ new byte[ETHER_ADDR_LEN] /* target HW address */,
+ tetherIp.getAddress() /* sender IP */, (short) ARP_REQUEST);
+ sendPacket(arpProbe);
+
+ final byte[] packet = getNextMatchedPacket((p) -> {
+ final ArpPacket arpPacket = parseArpPacket(p);
+ if (arpPacket == null || arpPacket.opCode != ARP_REPLY) return false;
+ return arpPacket.targetIp.equals(tetherIp);
+ });
+
+ if (packet != null) {
+ Log.d(TAG, "Get Mac address from ARP");
+ final ArpPacket arpReply = ArpPacket.parseArpPacket(packet, packet.length);
+ return arpReply.senderHwAddress;
+ }
+
+ fail("Could not get ARP packet");
+ return null;
+ }
+
public void sendPacket(ByteBuffer packet) throws Exception {
mDownstreamReader.sendResponse(packet);
}
public byte[] getNextMatchedPacket(Predicate<byte[]> filter) {
- return mDownstreamReader.poll(PACKET_READ_TIMEOUT_MS, filter);
+ byte[] packet;
+ while ((packet = mDownstreamReader.poll(PACKET_READ_TIMEOUT_MS)) != null) {
+ if (filter.test(packet)) return packet;
+
+ maybeReplyArp(packet);
+ }
+
+ return null;
+ }
+
+ public void verifyUpload(final RemoteResponder dst, final ByteBuffer packet,
+ final Predicate<byte[]> filter) throws Exception {
+ sendPacket(packet);
+ assertNotNull("Upload fail", dst.getNextMatchedPacket(filter));
}
public static class RemoteResponder {
@@ -167,5 +250,11 @@
public byte[] getNextMatchedPacket(Predicate<byte[]> filter) throws Exception {
return mUpstreamReader.poll(PACKET_READ_TIMEOUT_MS, filter);
}
+
+ public void verifyDownload(final TetheringTester dst, final ByteBuffer packet,
+ final Predicate<byte[]> filter) throws Exception {
+ sendPacket(packet);
+ assertNotNull("Download fail", dst.getNextMatchedPacket(filter));
+ }
}
}