Merge "Move ArpPacket.java to frameworks/libs/net" into main am: 027be158fc

Original change: https://android-review.googlesource.com/c/platform/frameworks/libs/net/+/2720913

Change-Id: Ibc1f622dd7b93d1e565f792a0580d1a8d3045798
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>

3 files changed, 373 insertions, 0 deletions

diff --git a/common/Android.bp b/common/Android.bp
index d3e68b75..0b42219c 100644
--- a/common/Android.bp
+++ b/common/Android.bp
@@ -34,6 +34,7 @@ package {
 java_library {
   name: "net-utils-device-common",
   srcs: [
+      "device/com/android/net/module/util/arp/ArpPacket.java",
       "device/com/android/net/module/util/DeviceConfigUtils.java",
       "device/com/android/net/module/util/DomainUtils.java",
       "device/com/android/net/module/util/FdEventsReader.java",
diff --git a/common/device/com/android/net/module/util/arp/ArpPacket.java b/common/device/com/android/net/module/util/arp/ArpPacket.java
new file mode 100644
index 00000000..dab9694b
--- /dev/null
+++ b/common/device/com/android/net/module/util/arp/ArpPacket.java
@@ -0,0 +1,171 @@
+/*
+ * Copyright (C) 2019 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 com.android.net.module.util.arp;
+
+import static android.system.OsConstants.ETH_P_ARP;
+import static android.system.OsConstants.ETH_P_IP;
+
+import static com.android.net.module.util.NetworkStackConstants.ARP_ETHER_IPV4_LEN;
+import static com.android.net.module.util.NetworkStackConstants.ARP_HWTYPE_ETHER;
+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.IPV4_ADDR_LEN;
+
+import android.net.MacAddress;
+
+import com.android.internal.annotations.VisibleForTesting;
+
+import java.net.Inet4Address;
+import java.net.InetAddress;
+import java.net.UnknownHostException;
+import java.nio.BufferUnderflowException;
+import java.nio.ByteBuffer;
+
+/**
+ * Defines basic data and operations needed to build and parse packets for the
+ * ARP protocol.
+ *
+ * @hide
+ */
+public class ArpPacket {
+    private static final String TAG = "ArpPacket";
+
+    public final short opCode;
+    public final Inet4Address senderIp;
+    public final Inet4Address targetIp;
+    public final MacAddress senderHwAddress;
+    public final MacAddress targetHwAddress;
+
+    ArpPacket(short opCode, MacAddress senderHwAddress, Inet4Address senderIp,
+            MacAddress targetHwAddress, Inet4Address targetIp) {
+        this.opCode = opCode;
+        this.senderHwAddress = senderHwAddress;
+        this.senderIp = senderIp;
+        this.targetHwAddress = targetHwAddress;
+        this.targetIp = targetIp;
+    }
+
+    /**
+     * Build an ARP packet from the required specified parameters.
+     */
+    @VisibleForTesting
+    public static ByteBuffer buildArpPacket(final byte[] dstMac, final byte[] srcMac,
+            final byte[] targetIp, final byte[] targetHwAddress, byte[] senderIp,
+            final short opCode) {
+        final ByteBuffer buf = ByteBuffer.allocate(ARP_ETHER_IPV4_LEN);
+
+        // Ether header
+        buf.put(dstMac);
+        buf.put(srcMac);
+        buf.putShort((short) ETH_P_ARP);
+
+        // ARP header
+        buf.putShort((short) ARP_HWTYPE_ETHER);  // hrd
+        buf.putShort((short) ETH_P_IP);          // pro
+        buf.put((byte) ETHER_ADDR_LEN);          // hln
+        buf.put((byte) IPV4_ADDR_LEN);           // pln
+        buf.putShort(opCode);                    // op
+        buf.put(srcMac);                         // sha
+        buf.put(senderIp);                       // spa
+        buf.put(targetHwAddress);                // tha
+        buf.put(targetIp);                       // tpa
+        buf.flip();
+        return buf;
+    }
+
+    /**
+     * Parse an ARP packet from a ByteBuffer object.
+     */
+    @VisibleForTesting
+    public static ArpPacket parseArpPacket(final byte[] recvbuf, final int length)
+            throws ParseException {
+        try {
+            if (length < ARP_ETHER_IPV4_LEN || recvbuf.length < length) {
+                throw new ParseException("Invalid packet length: " + length);
+            }
+
+            final ByteBuffer buffer = ByteBuffer.wrap(recvbuf, 0, length);
+            byte[] l2dst = new byte[ETHER_ADDR_LEN];
+            byte[] l2src = new byte[ETHER_ADDR_LEN];
+            buffer.get(l2dst);
+            buffer.get(l2src);
+
+            final short etherType = buffer.getShort();
+            if (etherType != ETH_P_ARP) {
+                throw new ParseException("Incorrect Ether Type: " + etherType);
+            }
+
+            final short hwType = buffer.getShort();
+            if (hwType != ARP_HWTYPE_ETHER) {
+                throw new ParseException("Incorrect HW Type: " + hwType);
+            }
+
+            final short protoType = buffer.getShort();
+            if (protoType != ETH_P_IP) {
+                throw new ParseException("Incorrect Protocol Type: " + protoType);
+            }
+
+            final byte hwAddrLength = buffer.get();
+            if (hwAddrLength != ETHER_ADDR_LEN) {
+                throw new ParseException("Incorrect HW address length: " + hwAddrLength);
+            }
+
+            final byte ipAddrLength = buffer.get();
+            if (ipAddrLength != IPV4_ADDR_LEN) {
+                throw new ParseException("Incorrect Protocol address length: " + ipAddrLength);
+            }
+
+            final short opCode = buffer.getShort();
+            if (opCode != ARP_REQUEST && opCode != ARP_REPLY) {
+                throw new ParseException("Incorrect opCode: " + opCode);
+            }
+
+            byte[] senderHwAddress = new byte[ETHER_ADDR_LEN];
+            byte[] senderIp = new byte[IPV4_ADDR_LEN];
+            buffer.get(senderHwAddress);
+            buffer.get(senderIp);
+
+            byte[] targetHwAddress = new byte[ETHER_ADDR_LEN];
+            byte[] targetIp = new byte[IPV4_ADDR_LEN];
+            buffer.get(targetHwAddress);
+            buffer.get(targetIp);
+
+            return new ArpPacket(opCode, MacAddress.fromBytes(senderHwAddress),
+                    (Inet4Address) InetAddress.getByAddress(senderIp),
+                    MacAddress.fromBytes(targetHwAddress),
+                    (Inet4Address) InetAddress.getByAddress(targetIp));
+        } catch (IndexOutOfBoundsException e) {
+            throw new ParseException("Invalid index when wrapping a byte array into a buffer");
+        } catch (BufferUnderflowException e) {
+            throw new ParseException("Invalid buffer position");
+        } catch (IllegalArgumentException e) {
+            throw new ParseException("Invalid MAC address representation");
+        } catch (UnknownHostException e) {
+            throw new ParseException("Invalid IP address of Host");
+        }
+    }
+
+    /**
+     * Thrown when parsing ARP packet failed.
+     */
+    public static class ParseException extends Exception {
+        ParseException(String message) {
+            super(message);
+        }
+    }
+}
diff --git a/common/tests/unit/src/com/android/net/module/util/ArpPacketTest.java b/common/tests/unit/src/com/android/net/module/util/ArpPacketTest.java
new file mode 100644
index 00000000..e25d5548
--- /dev/null
+++ b/common/tests/unit/src/com/android/net/module/util/ArpPacketTest.java
@@ -0,0 +1,201 @@
+/*
+ * Copyright (C) 2019 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 com.android.net.module.util;
+
+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 com.android.testutils.MiscAsserts.assertThrows;
+
+import static org.junit.Assert.assertArrayEquals;
+import static org.junit.Assert.assertEquals;
+
+import android.net.InetAddresses;
+import android.net.MacAddress;
+
+import androidx.test.filters.SmallTest;
+import androidx.test.runner.AndroidJUnit4;
+
+import com.android.net.module.util.arp.ArpPacket;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+import java.net.Inet4Address;
+import java.nio.ByteBuffer;
+
+@RunWith(AndroidJUnit4.class)
+@SmallTest
+public final class ArpPacketTest {
+
+    private static final Inet4Address TEST_IPV4_ADDR =
+            (Inet4Address) InetAddresses.parseNumericAddress("192.168.1.2");
+    private static final Inet4Address INADDR_ANY =
+            (Inet4Address) InetAddresses.parseNumericAddress("0.0.0.0");
+    private static final byte[] TEST_SENDER_MAC_ADDR = new byte[] {
+            0x00, 0x1a, 0x11, 0x22, 0x33, 0x33 };
+    private static final byte[] TEST_TARGET_MAC_ADDR = new byte[] {
+            0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
+    private static final byte[] TEST_ARP_PROBE = new byte[] {
+        // dst mac address
+        (byte) 0xff, (byte) 0xff, (byte) 0xff, (byte) 0xff, (byte) 0xff, (byte) 0xff,
+        // src mac address
+        (byte) 0x00, (byte) 0x1a, (byte) 0x11, (byte) 0x22, (byte) 0x33, (byte) 0x33,
+        // ether type
+        (byte) 0x08, (byte) 0x06,
+        // hardware type
+        (byte) 0x00, (byte) 0x01,
+        // protocol type
+        (byte) 0x08, (byte) 0x00,
+        // hardware address size
+        (byte) 0x06,
+        // protocol address size
+        (byte) 0x04,
+        // opcode
+        (byte) 0x00, (byte) 0x01,
+        // sender mac address
+        (byte) 0x00, (byte) 0x1a, (byte) 0x11, (byte) 0x22, (byte) 0x33, (byte) 0x33,
+        // sender IP address
+        (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00,
+        // target mac address
+        (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00,
+        // target IP address
+        (byte) 0xc0, (byte) 0xa8, (byte) 0x01, (byte) 0x02,
+    };
+
+    private static final byte[] TEST_ARP_ANNOUNCE = new byte[] {
+        // dst mac address
+        (byte) 0xff, (byte) 0xff, (byte) 0xff, (byte) 0xff, (byte) 0xff, (byte) 0xff,
+        // src mac address
+        (byte) 0x00, (byte) 0x1a, (byte) 0x11, (byte) 0x22, (byte) 0x33, (byte) 0x33,
+        // ether type
+        (byte) 0x08, (byte) 0x06,
+        // hardware type
+        (byte) 0x00, (byte) 0x01,
+        // protocol type
+        (byte) 0x08, (byte) 0x00,
+        // hardware address size
+        (byte) 0x06,
+        // protocol address size
+        (byte) 0x04,
+        // opcode
+        (byte) 0x00, (byte) 0x01,
+        // sender mac address
+        (byte) 0x00, (byte) 0x1a, (byte) 0x11, (byte) 0x22, (byte) 0x33, (byte) 0x33,
+        // sender IP address
+        (byte) 0xc0, (byte) 0xa8, (byte) 0x01, (byte) 0x02,
+        // target mac address
+        (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00,
+        // target IP address
+        (byte) 0xc0, (byte) 0xa8, (byte) 0x01, (byte) 0x02,
+    };
+
+    private static final byte[] TEST_ARP_PROBE_TRUNCATED = new byte[] {
+        // dst mac address
+        (byte) 0xff, (byte) 0xff, (byte) 0xff, (byte) 0xff, (byte) 0xff, (byte) 0xff,
+        // src mac address
+        (byte) 0x00, (byte) 0x1a, (byte) 0x11, (byte) 0x22, (byte) 0x33, (byte) 0x33,
+        // ether type
+        (byte) 0x08, (byte) 0x06,
+        // hardware type
+        (byte) 0x00, (byte) 0x01,
+        // protocol type
+        (byte) 0x08, (byte) 0x00,
+        // hardware address size
+        (byte) 0x06,
+        // protocol address size
+        (byte) 0x04,
+        // opcode
+        (byte) 0x00,
+    };
+
+    private static final byte[] TEST_ARP_PROBE_TRUNCATED_MAC = new byte[] {
+         // dst mac address
+        (byte) 0xff, (byte) 0xff, (byte) 0xff, (byte) 0xff, (byte) 0xff, (byte) 0xff,
+        // src mac address
+        (byte) 0x00, (byte) 0x1a, (byte) 0x11, (byte) 0x22, (byte) 0x33, (byte) 0x33,
+        // ether type
+        (byte) 0x08, (byte) 0x06,
+        // hardware type
+        (byte) 0x00, (byte) 0x01,
+        // protocol type
+        (byte) 0x08, (byte) 0x00,
+        // hardware address size
+        (byte) 0x06,
+        // protocol address size
+        (byte) 0x04,
+        // opcode
+        (byte) 0x00, (byte) 0x01,
+        // sender mac address
+        (byte) 0x00, (byte) 0x1a, (byte) 0x11, (byte) 0x22, (byte) 0x33,
+    };
+
+    @Test
+    public void testBuildArpProbePacket() throws Exception {
+        final ByteBuffer arpProbe = ArpPacket.buildArpPacket(ETHER_BROADCAST,
+                TEST_SENDER_MAC_ADDR, TEST_IPV4_ADDR.getAddress(), new byte[ETHER_ADDR_LEN],
+                INADDR_ANY.getAddress(), (short) ARP_REQUEST);
+        assertArrayEquals(arpProbe.array(), TEST_ARP_PROBE);
+    }
+
+    @Test
+    public void testBuildArpAnnouncePacket() throws Exception {
+        final ByteBuffer arpAnnounce = ArpPacket.buildArpPacket(ETHER_BROADCAST,
+                TEST_SENDER_MAC_ADDR, TEST_IPV4_ADDR.getAddress(), new byte[ETHER_ADDR_LEN],
+                TEST_IPV4_ADDR.getAddress(), (short) ARP_REQUEST);
+        assertArrayEquals(arpAnnounce.array(), TEST_ARP_ANNOUNCE);
+    }
+
+    @Test
+    public void testParseArpProbePacket() throws Exception {
+        final ArpPacket packet = ArpPacket.parseArpPacket(TEST_ARP_PROBE, TEST_ARP_PROBE.length);
+        assertEquals(packet.opCode, ARP_REQUEST);
+        assertEquals(packet.senderHwAddress, MacAddress.fromBytes(TEST_SENDER_MAC_ADDR));
+        assertEquals(packet.targetHwAddress, MacAddress.fromBytes(TEST_TARGET_MAC_ADDR));
+        assertEquals(packet.senderIp, INADDR_ANY);
+        assertEquals(packet.targetIp, TEST_IPV4_ADDR);
+    }
+
+    @Test
+    public void testParseArpAnnouncePacket() throws Exception {
+        final ArpPacket packet = ArpPacket.parseArpPacket(TEST_ARP_ANNOUNCE,
+                TEST_ARP_ANNOUNCE.length);
+        assertEquals(packet.opCode, ARP_REQUEST);
+        assertEquals(packet.senderHwAddress, MacAddress.fromBytes(TEST_SENDER_MAC_ADDR));
+        assertEquals(packet.targetHwAddress, MacAddress.fromBytes(TEST_TARGET_MAC_ADDR));
+        assertEquals(packet.senderIp, TEST_IPV4_ADDR);
+        assertEquals(packet.targetIp, TEST_IPV4_ADDR);
+    }
+
+    @Test
+    public void testParseArpPacket_invalidByteBufferParameters() throws Exception {
+        assertThrows(ArpPacket.ParseException.class, () -> ArpPacket.parseArpPacket(
+                TEST_ARP_PROBE, 0));
+    }
+
+    @Test
+    public void testParseArpPacket_truncatedPacket() throws Exception {
+        assertThrows(ArpPacket.ParseException.class, () -> ArpPacket.parseArpPacket(
+                TEST_ARP_PROBE_TRUNCATED, TEST_ARP_PROBE_TRUNCATED.length));
+    }
+
+    @Test
+    public void testParseArpPacket_truncatedMacAddress() throws Exception {
+        assertThrows(ArpPacket.ParseException.class, () -> ArpPacket.parseArpPacket(
+                TEST_ARP_PROBE_TRUNCATED_MAC, TEST_ARP_PROBE_TRUNCATED.length));
+    }
+}