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Commit 9b04481b authored by Xiao Ma's avatar Xiao Ma
Browse files

Add NeighborSolicitation class to build/prase NS packet. 

Bug: 162944199
Test: atest NetworkStackTests
Change-Id: Idbecee45de5a390a2997145b94bf319acef549bd
parent 6ef3d5b7

src/com/android/networkstack/packets/NeighborSolicitation.java

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/*

 * Copyright (C) 2021 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.networkstack.packets;



import static com.android.net.module.util.NetworkStackConstants.ETHER_HEADER_LEN;

import static com.android.net.module.util.NetworkStackConstants.ICMPV6_HEADER_MIN_LEN;

import static com.android.net.module.util.NetworkStackConstants.ICMPV6_ND_OPTION_SLLA;

import static com.android.net.module.util.NetworkStackConstants.IPV6_HEADER_LEN;



import android.net.MacAddress;



import androidx.annotation.NonNull;

import androidx.annotation.Nullable;



import com.android.net.module.util.Ipv6Utils;

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.Ipv6Header;

import com.android.net.module.util.structs.LlaOption;

import com.android.net.module.util.structs.NsHeader;



import java.net.Inet6Address;

import java.nio.ByteBuffer;



/**

 * Defines basic data and operations needed to build and parse Neighbor Solicitation packet.

 *

 * @hide

 */

public class NeighborSolicitation {

    private static final int NS_HEADER_LEN = Struct.getSize(NsHeader.class);



    @NonNull

    public final EthernetHeader ethHdr;

    @NonNull

    public final Ipv6Header ipv6Hdr;

    @NonNull

    public final Icmpv6Header icmpv6Hdr;

    @NonNull

    public final NsHeader nsHdr;

    @Nullable

    public final LlaOption slla;



    public NeighborSolicitation(@NonNull final EthernetHeader ethHdr,

            @NonNull final Ipv6Header ipv6Hdr, @NonNull final Icmpv6Header icmpv6Hdr,

            @NonNull final NsHeader nsHdr, @Nullable final LlaOption slla) {

        this.ethHdr = ethHdr;

        this.ipv6Hdr = ipv6Hdr;

        this.icmpv6Hdr = icmpv6Hdr;

        this.nsHdr = nsHdr;

        this.slla = slla;

    }



    /**

     * Convert a Neighbor Solicitation instance to ByteBuffer.

     */

    public ByteBuffer toByteBuffer() {

        final int etherHeaderLen = Struct.getSize(EthernetHeader.class);

        final int ipv6HeaderLen = Struct.getSize(Ipv6Header.class);

        final int icmpv6HeaderLen = Struct.getSize(Icmpv6Header.class);

        final int nsHeaderLen = Struct.getSize(NsHeader.class);

        final int sllaOptionLen = (slla == null) ? 0 : Struct.getSize(LlaOption.class);

        final ByteBuffer packet = ByteBuffer.allocate(etherHeaderLen + ipv6HeaderLen

                + icmpv6HeaderLen + nsHeaderLen + sllaOptionLen);



        ethHdr.writeToByteBuffer(packet);

        ipv6Hdr.writeToByteBuffer(packet);

        icmpv6Hdr.writeToByteBuffer(packet);

        nsHdr.writeToByteBuffer(packet);

        if (slla != null) {

            slla.writeToByteBuffer(packet);

        }

        packet.flip();



        return packet;

    }



    /**

     * Build a Neighbor Solicitation packet from the required specified parameters.

     */

    public static ByteBuffer build(@NonNull final MacAddress srcMac,

            @NonNull final MacAddress dstMac, @NonNull final Inet6Address srcIp,

            @NonNull final Inet6Address dstIp, @NonNull final Inet6Address target) {

        final ByteBuffer slla = LlaOption.build((byte) ICMPV6_ND_OPTION_SLLA, srcMac);

        return Ipv6Utils.buildNsPacket(srcMac, dstMac, srcIp, dstIp, target, slla);

    }



    /**

     * Parse a Neighbor Solicitation packet from ByteBuffer.

     */

    public static NeighborSolicitation parse(@NonNull final byte[] recvbuf, final int length)

            throws ParseException {

        if (length < ETHER_HEADER_LEN + IPV6_HEADER_LEN + ICMPV6_HEADER_MIN_LEN + NS_HEADER_LEN

                || recvbuf.length < length) {

            throw new ParseException("Invalid packet length: " + length);

        }

        final ByteBuffer packet = ByteBuffer.wrap(recvbuf, 0, length);



        // Parse each header and option in Neighbor Solicitation packet in order.

        final EthernetHeader ethHdr = Struct.parse(EthernetHeader.class, packet);

        final Ipv6Header ipv6Hdr = Struct.parse(Ipv6Header.class, packet);

        final Icmpv6Header icmpv6Hdr = Struct.parse(Icmpv6Header.class, packet);

        final NsHeader nsHdr = Struct.parse(NsHeader.class, packet);

        final LlaOption slla = (packet.remaining() == 0)

                ? null

                : Struct.parse(LlaOption.class, packet);



        return new NeighborSolicitation(ethHdr, ipv6Hdr, icmpv6Hdr, nsHdr, slla);

    }



    /**

     * Thrown when parsing Neighbor Solicitation packet failed.

     */

    public static class ParseException extends Exception {

        ParseException(String message) {

            super(message);

        }

    }

}

tests/unit/src/com/android/networkstack/packets/NeighborSolicitationTest.java

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Original line number Diff line number Diff line 
/*

 * Copyright (C) 2021 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.networkstack.packets;



import static android.system.OsConstants.ETH_P_IPV6;

import static android.system.OsConstants.IPPROTO_ICMPV6;



import static com.android.net.module.util.NetworkStackConstants.ICMPV6_NEIGHBOR_SOLICITATION;

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 org.junit.Test;

import org.junit.runner.RunWith;



import java.net.Inet6Address;

import java.nio.ByteBuffer;



@RunWith(AndroidJUnit4.class)

@SmallTest

public final class NeighborSolicitationTest {

    private static final Inet6Address TEST_SRC_ADDR =

            (Inet6Address) InetAddresses.parseNumericAddress("fe80::d419:d664:df38:2f65");

    private static final Inet6Address TEST_DST_ADDR =

            (Inet6Address) InetAddresses.parseNumericAddress("fe80::200:1a:1122:3344");

    private static final Inet6Address TEST_TARGET_ADDR =

            (Inet6Address) InetAddresses.parseNumericAddress("fe80::200:1a:1122:3344");

    private static final byte[] TEST_SOURCE_MAC_ADDR = new byte[] {

            (byte) 0x06, (byte) 0x5a, (byte) 0xac, (byte) 0x02, (byte) 0x61, (byte) 0x11,

    };

    private static final byte[] TEST_DST_MAC_ADDR = new byte[] {

            (byte) 0x00, (byte) 0x1a, (byte) 0x11, (byte) 0x22, (byte) 0x33, (byte) 0x44,

    };

    private static final byte[] TEST_NEIGHBOR_SOLICITATION = new byte[] {

        // dst mac address

        (byte) 0x00, (byte) 0x1a, (byte) 0x11, (byte) 0x22, (byte) 0x33, (byte) 0x44,

        // src mac address

        (byte) 0x06, (byte) 0x5a, (byte) 0xac, (byte) 0x02, (byte) 0x61, (byte) 0x11,

        // ether type

        (byte) 0x86, (byte) 0xdd,

        // version, priority and flow label

        (byte) 0x60, (byte) 0x00, (byte) 0x00, (byte) 0x00,

        // length

        (byte) 0x00, (byte) 0x20,

        // next header

        (byte) 0x3a,

        // hop limit

        (byte) 0xff,

        // source address

        (byte) 0xfe, (byte) 0x80, (byte) 0x00, (byte) 0x00,

        (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00,

        (byte) 0xd4, (byte) 0x19, (byte) 0xd6, (byte) 0x64,

        (byte) 0xdf, (byte) 0x38, (byte) 0x2f, (byte) 0x65,

        // destination address

        (byte) 0xfe, (byte) 0x80, (byte) 0x00, (byte) 0x00,

        (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00,

        (byte) 0x02, (byte) 0x00, (byte) 0x00, (byte) 0x1a,

        (byte) 0x11, (byte) 0x22, (byte) 0x33, (byte) 0x44,

        // ICMP type, code, checksum

        (byte) 0x87, (byte) 0x00, (byte) 0x22, (byte) 0x96,

        // reserved

        (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00,

        // target address

        (byte) 0xfe, (byte) 0x80, (byte) 0x00, (byte) 0x00,

        (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00,

        (byte) 0x02, (byte) 0x00, (byte) 0x00, (byte) 0x1a,

        (byte) 0x11, (byte) 0x22, (byte) 0x33, (byte) 0x44,

        // slla option

        (byte) 0x01, (byte) 0x01,

        // link-layer address

        (byte) 0x06, (byte) 0x5a, (byte) 0xac, (byte) 0x02,

        (byte) 0x61, (byte) 0x11,

    };

    private static final byte[] TEST_NEIGHBOR_SOLICITATION_WITHOUT_SLLA = new byte[] {

        // dst mac address

        (byte) 0x00, (byte) 0x1a, (byte) 0x11, (byte) 0x22, (byte) 0x33, (byte) 0x44,

        // src mac address

        (byte) 0x06, (byte) 0x5a, (byte) 0xac, (byte) 0x02, (byte) 0x61, (byte) 0x11,

        // ether type

        (byte) 0x86, (byte) 0xdd,

        // version, priority and flow label

        (byte) 0x60, (byte) 0x00, (byte) 0x00, (byte) 0x00,

        // length

        (byte) 0x00, (byte) 0x20,

        // next header

        (byte) 0x3a,

        // hop limit

        (byte) 0xff,

        // source address

        (byte) 0xfe, (byte) 0x80, (byte) 0x00, (byte) 0x00,

        (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00,

        (byte) 0xd4, (byte) 0x19, (byte) 0xd6, (byte) 0x64,

        (byte) 0xdf, (byte) 0x38, (byte) 0x2f, (byte) 0x65,

        // destination address

        (byte) 0xfe, (byte) 0x80, (byte) 0x00, (byte) 0x00,

        (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00,

        (byte) 0x02, (byte) 0x00, (byte) 0x00, (byte) 0x1a,

        (byte) 0x11, (byte) 0x22, (byte) 0x33, (byte) 0x44,

        // ICMP type, code, checksum

        (byte) 0x87, (byte) 0x00, (byte) 0x22, (byte) 0x96,

        // reserved

        (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00,

        // target address

        (byte) 0xfe, (byte) 0x80, (byte) 0x00, (byte) 0x00,

        (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00,

        (byte) 0x02, (byte) 0x00, (byte) 0x00, (byte) 0x1a,

        (byte) 0x11, (byte) 0x22, (byte) 0x33, (byte) 0x44,

    };

    private static final byte[] TEST_NEIGHBOR_SOLICITATION_LESS_LENGTH = new byte[] {

        // dst mac address

        (byte) 0x00, (byte) 0x1a, (byte) 0x11, (byte) 0x22, (byte) 0x33, (byte) 0x44,

        // src mac address

        (byte) 0x06, (byte) 0x5a, (byte) 0xac, (byte) 0x02, (byte) 0x61, (byte) 0x11,

        // ether type

        (byte) 0x86, (byte) 0xdd,

        // version, priority and flow label

        (byte) 0x60, (byte) 0x00, (byte) 0x00, (byte) 0x00,

        // length

        (byte) 0x00, (byte) 0x20,

        // next header

        (byte) 0x3a,

        // hop limit

        (byte) 0xff,

        // source address

        (byte) 0xfe, (byte) 0x80, (byte) 0x00, (byte) 0x00,

        (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00,

        (byte) 0xd4, (byte) 0x19, (byte) 0xd6, (byte) 0x64,

        (byte) 0xdf, (byte) 0x38, (byte) 0x2f, (byte) 0x65,

        // destination address

        (byte) 0xfe, (byte) 0x80, (byte) 0x00, (byte) 0x00,

        (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00,

        (byte) 0x02, (byte) 0x00, (byte) 0x00, (byte) 0x1a,

        (byte) 0x11, (byte) 0x22, (byte) 0x33, (byte) 0x44,

        // ICMP type, code, checksum

        (byte) 0x87, (byte) 0x00, (byte) 0x22, (byte) 0x96,

        // reserved

        (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00,

    };

    private static final byte[] TEST_NEIGHBOR_SOLICITATION_TRUNCATED = new byte[] {

        // dst mac address

        (byte) 0x00, (byte) 0x1a, (byte) 0x11, (byte) 0x22, (byte) 0x33, (byte) 0x44,

        // src mac address

        (byte) 0x06, (byte) 0x5a, (byte) 0xac, (byte) 0x02, (byte) 0x61, (byte) 0x11,

        // ether type

        (byte) 0x86, (byte) 0xdd,

        // version, priority and flow label

        (byte) 0x60, (byte) 0x00, (byte) 0x00, (byte) 0x00,

        // length

        (byte) 0x00, (byte) 0x20,

        // next header

        (byte) 0x3a,

        // hop limit

        (byte) 0xff,

        // source address

        (byte) 0xfe, (byte) 0x80, (byte) 0x00, (byte) 0x00,

        (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00,

        (byte) 0xd4, (byte) 0x19, (byte) 0xd6, (byte) 0x64,

        (byte) 0xdf, (byte) 0x38, (byte) 0x2f, (byte) 0x65,

        // destination address

        (byte) 0xfe, (byte) 0x80, (byte) 0x00, (byte) 0x00,

        (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00,

        (byte) 0x02, (byte) 0x00, (byte) 0x00, (byte) 0x1a,

        (byte) 0x11, (byte) 0x22, (byte) 0x33, (byte) 0x44,

        // ICMP type, code, checksum

        (byte) 0x87, (byte) 0x00, (byte) 0x22, (byte) 0x96,

        // reserved

        (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00,

        // target address

        (byte) 0xfe, (byte) 0x80, (byte) 0x00, (byte) 0x00,

        (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00,

        (byte) 0x02, (byte) 0x00, (byte) 0x00, (byte) 0x1a,

        (byte) 0x11, (byte) 0x22, (byte) 0x33, (byte) 0x44,

        // slla option

        (byte) 0x01, (byte) 0x01,

        // link-layer address

        (byte) 0x06, (byte) 0x5a, (byte) 0xac, (byte) 0x02,

    };



    @Test

    public void testNeighborSolicitation_build() throws Exception {

        final ByteBuffer ns = NeighborSolicitation.build(

                MacAddress.fromBytes(TEST_SOURCE_MAC_ADDR),

                MacAddress.fromBytes(TEST_DST_MAC_ADDR),

                TEST_SRC_ADDR, TEST_DST_ADDR, TEST_TARGET_ADDR);

        assertArrayEquals(ns.array(), TEST_NEIGHBOR_SOLICITATION);

    }



    private void assertNeighborSolicitation(final NeighborSolicitation ns, boolean hasSllaOption) {

        assertArrayEquals(TEST_SOURCE_MAC_ADDR, ns.ethHdr.srcMac.toByteArray());

        assertArrayEquals(TEST_DST_MAC_ADDR, ns.ethHdr.dstMac.toByteArray());

        assertEquals(ETH_P_IPV6, ns.ethHdr.etherType);

        assertEquals(IPPROTO_ICMPV6, ns.ipv6Hdr.nextHeader);

        assertEquals(0xff, ns.ipv6Hdr.hopLimit);

        assertEquals(TEST_DST_ADDR, ns.ipv6Hdr.dstIp);

        assertEquals(TEST_SRC_ADDR, ns.ipv6Hdr.srcIp);

        assertEquals(ICMPV6_NEIGHBOR_SOLICITATION, ns.icmpv6Hdr.type);

        assertEquals(0, ns.icmpv6Hdr.code);

        assertEquals(TEST_TARGET_ADDR, ns.nsHdr.target);

        if (hasSllaOption) {

            assertEquals(MacAddress.fromBytes(TEST_SOURCE_MAC_ADDR), ns.slla.linkLayerAddress);

        }

    }



    @Test

    public void testNeighborSolicitation_parse() throws Exception {

        final NeighborSolicitation ns = NeighborSolicitation.parse(TEST_NEIGHBOR_SOLICITATION,

                TEST_NEIGHBOR_SOLICITATION.length);



        assertNeighborSolicitation(ns, true /* hasSllaOption */);

        assertArrayEquals(TEST_NEIGHBOR_SOLICITATION, ns.toByteBuffer().array());

    }



    @Test

    public void testNeighborSolicitation_parseWithoutSllaOption() throws Exception {

        final NeighborSolicitation ns =

                NeighborSolicitation.parse(TEST_NEIGHBOR_SOLICITATION_WITHOUT_SLLA,

                        TEST_NEIGHBOR_SOLICITATION_WITHOUT_SLLA.length);



        assertNeighborSolicitation(ns, false /* hasSllaOption */);

        assertArrayEquals(TEST_NEIGHBOR_SOLICITATION_WITHOUT_SLLA, ns.toByteBuffer().array());

    }



    @Test

    public void testNeighborSolicitation_invalidPacketLength() throws Exception {

        assertThrows(NeighborSolicitation.ParseException.class,

                () -> NeighborSolicitation.parse(TEST_NEIGHBOR_SOLICITATION, 0));

    }



    @Test

    public void testNeighborSolicitation_invalidByteBufferLength() throws Exception {

        assertThrows(NeighborSolicitation.ParseException.class,

                () -> NeighborSolicitation.parse(TEST_NEIGHBOR_SOLICITATION_TRUNCATED,

                                                  TEST_NEIGHBOR_SOLICITATION.length));

    }



    @Test

    public void testNeighborSolicitation_lessPacketLength() throws Exception {

        assertThrows(NeighborSolicitation.ParseException.class,

                () -> NeighborSolicitation.parse(TEST_NEIGHBOR_SOLICITATION_LESS_LENGTH,

                                                  TEST_NEIGHBOR_SOLICITATION_LESS_LENGTH.length));

    }



    @Test

    public void testNeighborSolicitation_truncatedPacket() throws Exception {

        assertThrows(IllegalArgumentException.class,

                () -> NeighborSolicitation.parse(TEST_NEIGHBOR_SOLICITATION_TRUNCATED,

                                                  TEST_NEIGHBOR_SOLICITATION_TRUNCATED.length));

    }

}