tethering: DAD Proxy Daemon (79ca7f78) · Commits · e / os / android_frameworks_base

packages/Tethering/jni/android_net_util_TetheringUtils.cpp

+51 −1

Original line number	Diff line number	Diff line
		@@ -17,18 +17,63 @@
		#include <errno.h>
		#include <error.h>
		#include <jni.h>
		#include <linux/filter.h>
		#include <nativehelper/JNIHelp.h>
		#include <nativehelper/JNIHelpCompat.h>
		#include <nativehelper/ScopedUtfChars.h>
		#include <net/if.h>
		#include <netinet/ether.h>
		#include <netinet/ip6.h>
		#include <netinet/icmp6.h>
		#include <sys/socket.h>
		#include <stdio.h>

		#define LOG_TAG "TetheringUtils"
		#include <android/log.h>

		namespace android {

		static const uint32_t kIPv6NextHeaderOffset = offsetof(ip6_hdr, ip6_nxt);
		static const uint32_t kIPv6PayloadStart = sizeof(ip6_hdr);
		static const uint32_t kICMPv6TypeOffset = kIPv6PayloadStart + offsetof(icmp6_hdr, icmp6_type);

		static void android_net_util_setupIcmpFilter(JNIEnv *env, jobject javaFd, uint32_t type) {
		sock_filter filter_code[] = {
		// Check header is ICMPv6.
		BPF_STMT(BPF_LD \| BPF_B \| BPF_ABS, kIPv6NextHeaderOffset),
		BPF_JUMP(BPF_JMP \| BPF_JEQ \| BPF_K, IPPROTO_ICMPV6, 0, 3),

		// Check ICMPv6 type.
		BPF_STMT(BPF_LD \| BPF_B \| BPF_ABS, kICMPv6TypeOffset),
		BPF_JUMP(BPF_JMP \| BPF_JEQ \| BPF_K, type, 0, 1),

		// Accept or reject.
		BPF_STMT(BPF_RET \| BPF_K, 0xffff),
		BPF_STMT(BPF_RET \| BPF_K, 0)
		};

		const sock_fprog filter = {
		sizeof(filter_code) / sizeof(filter_code[0]),
		filter_code,
		};

		int fd = jniGetFDFromFileDescriptor(env, javaFd);
		if (setsockopt(fd, SOL_SOCKET, SO_ATTACH_FILTER, &filter, sizeof(filter)) != 0) {
		jniThrowExceptionFmt(env, "java/net/SocketException",
		"setsockopt(SO_ATTACH_FILTER): %s", strerror(errno));
		}
		}

		static void android_net_util_setupNaSocket(JNIEnv *env, jobject clazz, jobject javaFd)
		{
		android_net_util_setupIcmpFilter(env, javaFd, ND_NEIGHBOR_ADVERT);
		}

		static void android_net_util_setupNsSocket(JNIEnv *env, jobject clazz, jobject javaFd)
		{
		android_net_util_setupIcmpFilter(env, javaFd, ND_NEIGHBOR_SOLICIT);
		}

		static void android_net_util_setupRaSocket(JNIEnv *env, jobject clazz, jobject javaFd,
		jint ifIndex)
		{
		@@ -125,7 +170,12 @@ static void android_net_util_setupRaSocket(JNIEnv *env, jobject clazz, jobject j
		*/
		static const JNINativeMethod gMethods[] = {
		/* name, signature, funcPtr */
		{ "setupRaSocket", "(Ljava/io/FileDescriptor;I)V", (void*) android_net_util_setupRaSocket },
		{ "setupNaSocket", "(Ljava/io/FileDescriptor;)V",
		(void*) android_net_util_setupNaSocket },
		{ "setupNsSocket", "(Ljava/io/FileDescriptor;)V",
		(void*) android_net_util_setupNsSocket },
		{ "setupRaSocket", "(Ljava/io/FileDescriptor;I)V",
		(void*) android_net_util_setupRaSocket },
		};

		int register_android_net_util_TetheringUtils(JNIEnv* env) {

packages/Tethering/src/android/net/ip/DadProxy.java

0 → 100644

+54 −0

Original line number	Diff line number	Diff line
		/*
		* Copyright (C) 2020 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 android.net.ip;

		import android.net.util.InterfaceParams;
		import android.os.Handler;

		import androidx.annotation.VisibleForTesting;

		/**
		* Basic Duplicate address detection proxy.
		*
		* @hide
		*/
		public class DadProxy {
		private static final String TAG = DadProxy.class.getSimpleName();

		@VisibleForTesting
		public static NeighborPacketForwarder naForwarder;
		public static NeighborPacketForwarder nsForwarder;

		public DadProxy(Handler h, InterfaceParams tetheredIface) {
		naForwarder = new NeighborPacketForwarder(h, tetheredIface,
		NeighborPacketForwarder.ICMPV6_NEIGHBOR_ADVERTISEMENT);
		nsForwarder = new NeighborPacketForwarder(h, tetheredIface,
		NeighborPacketForwarder.ICMPV6_NEIGHBOR_SOLICITATION);
		}

		/** Stop NS/NA Forwarders. */
		public void stop() {
		naForwarder.stop();
		nsForwarder.stop();
		}

		/** Set upstream iface on both forwarders. */
		public void setUpstreamIface(InterfaceParams upstreamIface) {
		naForwarder.setUpstreamIface(upstreamIface);
		nsForwarder.setUpstreamIface(upstreamIface);
		}
		}

packages/Tethering/src/android/net/ip/IpServer.java

+37 −8

Original line number	Diff line number	Diff line
		@@ -51,6 +51,7 @@ import android.net.util.InterfaceParams;
		import android.net.util.InterfaceSet;
		import android.net.util.PrefixUtils;
		import android.net.util.SharedLog;
		import android.os.Build;
		import android.os.Handler;
		import android.os.Looper;
		import android.os.Message;
		@@ -160,6 +161,15 @@ public class IpServer extends StateMachine {

		/** Capture IpServer dependencies, for injection. */
		public abstract static class Dependencies {
		/**
		* Create a DadProxy instance to be used by IpServer.
		* To support multiple tethered interfaces concurrently DAD Proxy
		* needs to be supported per IpServer instead of per upstream.
		*/
		public DadProxy getDadProxy(Handler handler, InterfaceParams ifParams) {
		return new DadProxy(handler, ifParams);
		}

		/** Create an IpNeighborMonitor to be used by this IpServer */
		public IpNeighborMonitor getIpNeighborMonitor(Handler handler, SharedLog log,
		IpNeighborMonitor.NeighborEventConsumer consumer) {
		@@ -256,6 +266,7 @@ public class IpServer extends StateMachine {
		// Advertisements (otherwise, we do not add them to mLinkProperties at all).
		private LinkProperties mLastIPv6LinkProperties;
		private RouterAdvertisementDaemon mRaDaemon;
		private DadProxy mDadProxy;

		// To be accessed only on the handler thread
		private int mDhcpServerStartIndex = 0;
		@@ -674,6 +685,13 @@ public class IpServer extends StateMachine {
		return false;
		}

		// TODO: use ShimUtils instead of explicitly checking the version here.
		if (Build.VERSION.SDK_INT > Build.VERSION_CODES.R \|\| "S".equals(Build.VERSION.CODENAME)
		\|\| "T".equals(Build.VERSION.CODENAME)) {
		// DAD Proxy starts forwarding packets after IPv6 upstream is present.
		mDadProxy = mDeps.getDadProxy(getHandler(), mInterfaceParams);
		}

		return true;
		}

		@@ -685,6 +703,11 @@ public class IpServer extends StateMachine {
		mRaDaemon.stop();
		mRaDaemon = null;
		}

		if (mDadProxy != null) {
		mDadProxy.stop();
		mDadProxy = null;
		}
		}

		// IPv6TetheringCoordinator sends updates with carefully curated IPv6-only
		@@ -702,11 +725,16 @@ public class IpServer extends StateMachine {
		}

		RaParams params = null;
		int upstreamIfindex = 0;
		String upstreamIface = null;
		InterfaceParams upstreamIfaceParams = null;
		int upstreamIfIndex = 0;

		if (v6only != null) {
		final String upstreamIface = v6only.getInterfaceName();

		upstreamIface = v6only.getInterfaceName();
		upstreamIfaceParams = mDeps.getInterfaceParams(upstreamIface);
		if (upstreamIfaceParams != null) {
		upstreamIfIndex = upstreamIfaceParams.index;
		}
		params = new RaParams();
		params.mtu = v6only.getMtu();
		params.hasDefaultRoute = v6only.hasIpv6DefaultRoute();
		@@ -726,15 +754,13 @@ public class IpServer extends StateMachine {
		}
		}

		upstreamIfindex = mDeps.getIfindex(upstreamIface);

		// Add upstream index to name mapping for the tether stats usage in the coordinator.
		// Although this mapping could be added by both class Tethering and IpServer, adding
		// mapping from IpServer guarantees that the mapping is added before the adding
		// forwarding rules. That is because there are different state machines in both
		// classes. It is hard to guarantee the link property update order between multiple
		// state machines.
		mBpfCoordinator.addUpstreamNameToLookupTable(upstreamIfindex, upstreamIface);
		mBpfCoordinator.addUpstreamNameToLookupTable(upstreamIfIndex, upstreamIface);
		}

		// If v6only is null, we pass in null to setRaParams(), which handles
		@@ -743,8 +769,11 @@ public class IpServer extends StateMachine {
		setRaParams(params);
		mLastIPv6LinkProperties = v6only;

		updateIpv6ForwardingRules(mLastIPv6UpstreamIfindex, upstreamIfindex, null);
		mLastIPv6UpstreamIfindex = upstreamIfindex;
		updateIpv6ForwardingRules(mLastIPv6UpstreamIfindex, upstreamIfIndex, null);
		mLastIPv6UpstreamIfindex = upstreamIfIndex;
		if (mDadProxy != null) {
		mDadProxy.setUpstreamIface(upstreamIfaceParams);
		}
		}

		private void removeRoutesFromLocalNetwork(@NonNull final List<RouteInfo> toBeRemoved) {

packages/Tethering/src/android/net/ip/NeighborPacketForwarder.java

0 → 100644

+180 −0

Original line number	Diff line number	Diff line
		/*
		* Copyright (C) 2020 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 android.net.ip;

		import static android.system.OsConstants.AF_INET6;
		import static android.system.OsConstants.AF_PACKET;
		import static android.system.OsConstants.ETH_P_IPV6;
		import static android.system.OsConstants.IPPROTO_RAW;
		import static android.system.OsConstants.SOCK_DGRAM;
		import static android.system.OsConstants.SOCK_NONBLOCK;
		import static android.system.OsConstants.SOCK_RAW;

		import android.net.util.InterfaceParams;
		import android.net.util.PacketReader;
		import android.net.util.SocketUtils;
		import android.net.util.TetheringUtils;
		import android.os.Handler;
		import android.system.ErrnoException;
		import android.system.Os;
		import android.util.Log;

		import java.io.FileDescriptor;
		import java.io.IOException;
		import java.net.Inet6Address;
		import java.net.InetSocketAddress;
		import java.net.SocketAddress;
		import java.net.SocketException;
		import java.net.UnknownHostException;
		import java.util.Arrays;

		/**
		* Basic IPv6 Neighbor Advertisement Forwarder.
		*
		* Forward NA packets from upstream iface to tethered iface
		* and NS packets from tethered iface to upstream iface.
		*
		* @hide
		*/
		public class NeighborPacketForwarder extends PacketReader {
		private final String mTag;

		private FileDescriptor mFd;

		// TODO: get these from NetworkStackConstants.
		private static final int IPV6_ADDR_LEN = 16;
		private static final int IPV6_DST_ADDR_OFFSET = 24;
		private static final int IPV6_HEADER_LEN = 40;
		private static final int ETH_HEADER_LEN = 14;

		private InterfaceParams mListenIfaceParams, mSendIfaceParams;

		private final int mType;
		public static final int ICMPV6_NEIGHBOR_ADVERTISEMENT = 136;
		public static final int ICMPV6_NEIGHBOR_SOLICITATION = 135;

		public NeighborPacketForwarder(Handler h, InterfaceParams tetheredInterface, int type) {
		super(h);
		mTag = NeighborPacketForwarder.class.getSimpleName() + "-"
		+ tetheredInterface.name + "-" + type;
		mType = type;

		if (mType == ICMPV6_NEIGHBOR_ADVERTISEMENT) {
		mSendIfaceParams = tetheredInterface;
		} else {
		mListenIfaceParams = tetheredInterface;
		}
		}

		/** Set new upstream iface and start/stop based on new params. */
		public void setUpstreamIface(InterfaceParams upstreamParams) {
		final InterfaceParams oldUpstreamParams;

		if (mType == ICMPV6_NEIGHBOR_ADVERTISEMENT) {
		oldUpstreamParams = mListenIfaceParams;
		mListenIfaceParams = upstreamParams;
		} else {
		oldUpstreamParams = mSendIfaceParams;
		mSendIfaceParams = upstreamParams;
		}

		if (oldUpstreamParams == null && upstreamParams != null) {
		start();
		} else if (oldUpstreamParams != null && upstreamParams == null) {
		stop();
		} else if (oldUpstreamParams != null && upstreamParams != null
		&& oldUpstreamParams.index != upstreamParams.index) {
		stop();
		start();
		}
		}

		// TODO: move NetworkStackUtils.closeSocketQuietly to
		// frameworks/libs/net/common/device/com/android/net/module/util/[someclass].
		private void closeSocketQuietly(FileDescriptor fd) {
		try {
		SocketUtils.closeSocket(fd);
		} catch (IOException ignored) {
		}
		}

		@Override
		protected FileDescriptor createFd() {
		try {
		// ICMPv6 packets from modem do not have eth header, so RAW socket cannot be used.
		// To keep uniformity in both directions PACKET socket can be used.
		mFd = Os.socket(AF_PACKET, SOCK_DGRAM \| SOCK_NONBLOCK, 0);

		// TODO: convert setup*Socket to setupICMPv6BpfFilter with filter type?
		if (mType == ICMPV6_NEIGHBOR_ADVERTISEMENT) {
		TetheringUtils.setupNaSocket(mFd);
		} else if (mType == ICMPV6_NEIGHBOR_SOLICITATION) {
		TetheringUtils.setupNsSocket(mFd);
		}

		SocketAddress bindAddress = SocketUtils.makePacketSocketAddress(
		ETH_P_IPV6, mListenIfaceParams.index);
		Os.bind(mFd, bindAddress);
		} catch (ErrnoException \| SocketException e) {
		Log.wtf(mTag, "Failed to create socket", e);
		closeSocketQuietly(mFd);
		return null;
		}

		return mFd;
		}

		private Inet6Address getIpv6DestinationAddress(byte[] recvbuf) {
		Inet6Address dstAddr;
		try {
		dstAddr = (Inet6Address) Inet6Address.getByAddress(Arrays.copyOfRange(recvbuf,
		IPV6_DST_ADDR_OFFSET, IPV6_DST_ADDR_OFFSET + IPV6_ADDR_LEN));
		} catch (UnknownHostException \| ClassCastException impossible) {
		throw new AssertionError("16-byte array not valid IPv6 address?");
		}
		return dstAddr;
		}

		@Override
		protected void handlePacket(byte[] recvbuf, int length) {
		if (mSendIfaceParams == null) {
		return;
		}

		// The BPF filter should already have checked the length of the packet, but...
		if (length < IPV6_HEADER_LEN) {
		return;
		}
		Inet6Address destv6 = getIpv6DestinationAddress(recvbuf);
		if (!destv6.isMulticastAddress()) {
		return;
		}
		InetSocketAddress dest = new InetSocketAddress(destv6, 0);

		FileDescriptor fd = null;
		try {
		fd = Os.socket(AF_INET6, SOCK_RAW \| SOCK_NONBLOCK, IPPROTO_RAW);
		SocketUtils.bindSocketToInterface(fd, mSendIfaceParams.name);

		int ret = Os.sendto(fd, recvbuf, 0, length, 0, dest);
		} catch (ErrnoException \| SocketException e) {
		Log.e(mTag, "handlePacket error: " + e);
		} finally {
		closeSocketQuietly(fd);
		}
		}
		}

packages/Tethering/src/android/net/ip/RouterAdvertisementDaemon.java

+1 −15

Original line number	Diff line number	Diff line
		@@ -18,6 +18,7 @@ package android.net.ip;

		import static android.net.util.NetworkConstants.IPV6_MIN_MTU;
		import static android.net.util.NetworkConstants.RFC7421_PREFIX_LENGTH;
		import static android.net.util.TetheringUtils.getAllNodesForScopeId;
		import static android.system.OsConstants.AF_INET6;
		import static android.system.OsConstants.IPPROTO_ICMPV6;
		import static android.system.OsConstants.SOCK_RAW;
		@@ -44,7 +45,6 @@ import java.net.Inet6Address;
		import java.net.InetAddress;
		import java.net.InetSocketAddress;
		import java.net.SocketException;
		import java.net.UnknownHostException;
		import java.nio.BufferOverflowException;
		import java.nio.ByteBuffer;
		import java.nio.ByteOrder;
		@@ -92,10 +92,6 @@ public class RouterAdvertisementDaemon {

		private static final int DAY_IN_SECONDS = 86_400;

		private static final byte[] ALL_NODES = new byte[] {
		(byte) 0xff, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1
		};

		private final InterfaceParams mInterface;
		private final InetSocketAddress mAllNodes;

		@@ -240,7 +236,6 @@ public class RouterAdvertisementDaemon {
		}
		}


		public RouterAdvertisementDaemon(InterfaceParams ifParams) {
		mInterface = ifParams;
		mAllNodes = new InetSocketAddress(getAllNodesForScopeId(mInterface.index), 0);
		@@ -363,15 +358,6 @@ public class RouterAdvertisementDaemon {
		}
		}

		private static Inet6Address getAllNodesForScopeId(int scopeId) {
		try {
		return Inet6Address.getByAddress("ff02::1", ALL_NODES, scopeId);
		} catch (UnknownHostException uhe) {
		Log.wtf(TAG, "Failed to construct ff02::1 InetAddress: " + uhe);
		return null;
		}
		}

		private static byte asByte(int value) {
		return (byte) value;
		}