0ca094b577
Instead of (wrongly) looking at the DNS message flags for the Query Unicast bit, look at the flag in the question record. The previous bug means that all queries would be replied multicast instead of sometimes unicast. The fix is flagged off as this is a behavior change that may affect performance and latency. Bug: 289482497 Test: atest Change-Id: I08e30c4ffa747c9073d631e8addca1278ea40648
86 lines
3.3 KiB
Kotlin
86 lines
3.3 KiB
Kotlin
/*
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* Copyright (C) 2023 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package com.android.testutils
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import android.net.MacAddress
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import android.util.Log
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import com.android.net.module.util.Ipv6Utils
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import com.android.net.module.util.NetworkStackConstants.ETHER_HEADER_LEN
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import com.android.net.module.util.NetworkStackConstants.ICMPV6_ND_OPTION_TLLA
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import com.android.net.module.util.NetworkStackConstants.NEIGHBOR_ADVERTISEMENT_FLAG_SOLICITED
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import com.android.net.module.util.Struct
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import com.android.net.module.util.structs.Icmpv6Header
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import com.android.net.module.util.structs.Ipv6Header
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import com.android.net.module.util.structs.LlaOption
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import com.android.net.module.util.structs.NsHeader
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import com.android.testutils.PacketReflector.IPV6_HEADER_LENGTH
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import java.lang.IllegalArgumentException
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import java.net.Inet6Address
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import java.nio.ByteBuffer
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private const val NS_TYPE = 135.toShort()
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/**
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* A class that can be used to reply to Neighbor Solicitation packets on a [TapPacketReader].
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*/
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class NSResponder(
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reader: TapPacketReader,
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table: Map<Inet6Address, MacAddress>,
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name: String = NSResponder::class.java.simpleName
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) : PacketResponder(reader, Icmpv6Filter(), name) {
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companion object {
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private val TAG = NSResponder::class.simpleName
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}
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// Copy the map if not already immutable (toMap) to make sure it is not modified
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private val table = table.toMap()
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override fun replyToPacket(packet: ByteArray, reader: TapPacketReader) {
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if (packet.size < IPV6_HEADER_LENGTH) {
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return
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}
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val buf = ByteBuffer.wrap(packet, ETHER_HEADER_LEN, packet.size - ETHER_HEADER_LEN)
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val ipv6Header = parseOrLog(Ipv6Header::class.java, buf) ?: return
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val icmpHeader = parseOrLog(Icmpv6Header::class.java, buf) ?: return
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if (icmpHeader.type != NS_TYPE) {
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return
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}
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val ns = parseOrLog(NsHeader::class.java, buf) ?: return
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val replyMacAddr = table[ns.target] ?: return
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val slla = parseOrLog(LlaOption::class.java, buf) ?: return
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val requesterMac = slla.linkLayerAddress
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val tlla = LlaOption.build(ICMPV6_ND_OPTION_TLLA.toByte(), replyMacAddr)
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reader.sendResponse(Ipv6Utils.buildNaPacket(
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replyMacAddr /* srcMac */,
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requesterMac /* dstMac */,
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ns.target /* srcIp */,
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ipv6Header.srcIp /* dstIp */,
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NEIGHBOR_ADVERTISEMENT_FLAG_SOLICITED,
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ns.target,
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tlla))
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}
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private fun <T> parseOrLog(clazz: Class<T>, buf: ByteBuffer): T? where T : Struct {
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return try {
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Struct.parse(clazz, buf)
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} catch (e: IllegalArgumentException) {
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Log.e(TAG, "Invalid ${clazz.simpleName} in ICMPv6 packet", e)
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null
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}
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}
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}
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