Add test for NetworkStackUtils.attachRaFilter

import android.Manifest.permission.MANAGE_TEST_NETWORKS

import android.content.Context

import android.net.InetAddresses.parseNumericAddress

import android.net.IpPrefix

import android.net.MacAddress

import android.net.TestNetworkInterface

import android.net.TestNetworkManager

import android.os.HandlerThread

import android.system.Os

import android.system.OsConstants.AF_INET

import android.system.OsConstants.AF_PACKET

import android.system.OsConstants.ARPHRD_ETHER

import android.system.OsConstants.ETH_P_IPV6

import android.system.OsConstants.IPPROTO_UDP

import android.system.OsConstants.SOCK_DGRAM

import android.system.OsConstants.SOCK_NONBLOCK

import androidx.test.platform.app.InstrumentationRegistry

import android.system.OsConstants.SOCK_RAW

import android.system.OsConstants.SOL_SOCKET

import android.system.OsConstants.SO_RCVTIMEO

import android.system.StructTimeval

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

import com.android.net.module.util.NetworkStackConstants.ETHER_ADDR_LEN

import com.android.net.module.util.NetworkStackConstants.IPV4_ADDR_ANY

import com.android.net.module.util.NetworkStackConstants.IPV6_ADDR_ALL_NODES_MULTICAST

import com.android.net.module.util.structs.PrefixInformationOption

import com.android.testutils.ArpRequestFilter

import com.android.testutils.ETHER_HEADER_LENGTH

import com.android.testutils.IPV4_HEADER_LENGTH

import org.junit.Assert.assertArrayEquals

import org.junit.Before

import org.junit.Test

import java.io.FileDescriptor

import java.net.Inet4Address

import kotlin.reflect.KClass

import java.net.Inet6Address

import java.nio.ByteBuffer

import kotlin.test.assertEquals

import kotlin.test.assertTrue

import kotlin.test.fail

class NetworkStackUtilsIntegrationTest {

    private val context by lazy { inst.context }

    private val TEST_TIMEOUT_MS = 10_000L

    private val TEST_MTU = 1500

    private val TEST_TARGET_IPV4_ADDR = parseNumericAddress("192.0.2.42") as Inet4Address

    private val TEST_SRC_MAC = MacAddress.fromString("BA:98:76:54:32:10")

    private val TEST_TARGET_MAC = MacAddress.fromString("01:23:45:67:89:0A")

    private val TEST_INET6ADDR_1 = parseNumericAddress("2001:db8::1") as Inet6Address

    private val TEST_INET6ADDR_2 = parseNumericAddress("2001:db8::2") as Inet6Address

    private val readerHandler = HandlerThread(

            NetworkStackUtilsIntegrationTest::class.java.simpleName)

                null /* hostname */, false /* metered */, 1500 /* mtu */,

                null /* captivePortalUrl */)

        // Not using .array as per errorprone "ByteBufferBackingArray" recommendation

        val originalPacket = ByteArray(buffer.limit())

        buffer.get(originalPacket)

        val originalPacket = buffer.readAsArray()

        Os.sendto(socket, originalPacket, 0 /* bytesOffset */, originalPacket.size /* bytesCount */,

                0 /* flags */, TEST_TARGET_IPV4_ADDR, DhcpPacket.DHCP_CLIENT.toInt() /* port */)

        // Verify the packet was sent to the mac address specified in the ARP entry

        // Also accept ARP requests, but expect that none is sent before the UDP packet

        // IPv6 NS may be sent on the interface but will be filtered out

        val sentPacket = reader.popPacket(TEST_TIMEOUT_MS, IPv4UdpFilter().or(ArpRequestFilter()))

        val sentPacket = reader.poll(TEST_TIMEOUT_MS, IPv4UdpFilter().or(ArpRequestFilter()))

                ?: fail("Packet was not sent on the interface")

        val sentTargetAddr = MacAddress.fromBytes(sentPacket.copyOfRange(0, ETHER_ADDR_LEN))

        assertArrayEquals("Sent packet != original packet", originalPacket, sentDhcpPacket)

    }

    @Test

    fun testAttachRaFilter() {

        val socket = Os.socket(AF_PACKET, SOCK_RAW, ETH_P_IPV6)

        val ifParams = InterfaceParams.getByName(iface.interfaceName)

                ?: fail("Could not obtain interface params for ${iface.interfaceName}")

        val socketAddr = SocketUtils.makePacketSocketAddress(ETH_P_IPV6, ifParams.index)

        Os.bind(socket, socketAddr)

        Os.setsockoptTimeval(socket, SOL_SOCKET, SO_RCVTIMEO,

                StructTimeval.fromMillis(TEST_TIMEOUT_MS))

        // Verify that before setting any filter, the socket receives pings

        val echo = Ipv6Utils.buildEchoRequestPacket(TEST_SRC_MAC, TEST_TARGET_MAC, TEST_INET6ADDR_1,

                TEST_INET6ADDR_2)

        reader.sendResponse(echo)

        echo.rewind()

        assertNextPacketEquals(socket, echo.readAsArray(), "ICMPv6 echo")

        NetworkStackUtils.attachRaFilter(socket, ARPHRD_ETHER)

        // Send another echo, then an RA. After setting the filter expect only the RA.

        echo.rewind()

        reader.sendResponse(echo)

        val pio = PrefixInformationOption.build(IpPrefix("2001:db8:1::/64"),

                0.toByte() /* flags */, 3600 /* validLifetime */, 1800 /* preferredLifetime */)

        val ra = Ipv6Utils.buildRaPacket(TEST_SRC_MAC, TEST_TARGET_MAC,

                TEST_INET6ADDR_1 /* routerAddr */, IPV6_ADDR_ALL_NODES_MULTICAST,

                0.toByte() /* flags */, 1800 /* lifetime */, 0 /* reachableTime */,

                0 /* retransTimer */, pio)

        reader.sendResponse(ra)

        ra.rewind()

        assertNextPacketEquals(socket, ra.readAsArray(), "ICMPv6 RA")

    }

    private fun assertNextPacketEquals(socket: FileDescriptor, expected: ByteArray, descr: String) {

        val buffer = ByteArray(TEST_MTU)

        val readPacket = Os.read(socket, buffer, 0 /* byteOffset */, buffer.size)

        assertTrue(readPacket > 0, "$descr not received")

        assertEquals(expected.size, readPacket, "Received packet size does not match for $descr")

        assertArrayEquals("Received packet != expected $descr",

                expected, buffer.copyOfRange(0, readPacket))

    }

}

private fun ByteBuffer.readAsArray(): ByteArray {

    val out = ByteArray(remaining())

    get(out)

    return out

}

private fun <T : Any> Context.assertHasService(manager: KClass<T>) = getSystemService(manager.java)