Allow tethering to use IpNeighborMonitor.
Test: m
Change-Id: I4ca0c47d62ea90c30f88278b3ebf766be2c5a2e9
diff --git a/common/moduleutils/Android.bp b/common/moduleutils/Android.bp
index 4b2a4b8..d0dd584 100644
--- a/common/moduleutils/Android.bp
+++ b/common/moduleutils/Android.bp
@@ -51,10 +51,14 @@
name: "tethering-module-utils-srcs",
srcs: [
"src/android/net/ip/InterfaceController.java",
+ "src/android/net/ip/IpNeighborMonitor.java",
"src/android/net/netlink/*.java",
"src/android/net/shared/NetdUtils.java",
"src/android/net/shared/RouteUtils.java",
+ "src/android/net/util/FdEventsReader.java",
"src/android/net/util/InterfaceParams.java",
+ "src/android/net/util/PacketReader.java",
"src/android/net/util/SharedLog.java"
],
+ visibility: ["//frameworks/base/packages/Tethering"],
}
diff --git a/common/moduleutils/src/android/net/ip/IpNeighborMonitor.java b/common/moduleutils/src/android/net/ip/IpNeighborMonitor.java
new file mode 100644
index 0000000..d6706d4
--- /dev/null
+++ b/common/moduleutils/src/android/net/ip/IpNeighborMonitor.java
@@ -0,0 +1,250 @@
+/*
+ * Copyright (C) 2017 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.net.netlink.NetlinkConstants.RTM_DELNEIGH;
+import static android.net.netlink.NetlinkConstants.hexify;
+import static android.net.netlink.NetlinkConstants.stringForNlMsgType;
+import static android.net.util.SocketUtils.makeNetlinkSocketAddress;
+import static android.system.OsConstants.AF_NETLINK;
+import static android.system.OsConstants.NETLINK_ROUTE;
+import static android.system.OsConstants.SOCK_DGRAM;
+import static android.system.OsConstants.SOCK_NONBLOCK;
+
+import android.net.MacAddress;
+import android.net.netlink.NetlinkErrorMessage;
+import android.net.netlink.NetlinkMessage;
+import android.net.netlink.NetlinkSocket;
+import android.net.netlink.RtNetlinkNeighborMessage;
+import android.net.netlink.StructNdMsg;
+import android.net.util.PacketReader;
+import android.net.util.SharedLog;
+import android.net.util.SocketUtils;
+import android.os.Handler;
+import android.os.SystemClock;
+import android.system.ErrnoException;
+import android.system.Os;
+import android.system.OsConstants;
+import android.util.Log;
+
+import java.io.FileDescriptor;
+import java.io.IOException;
+import java.net.InetAddress;
+import java.net.SocketAddress;
+import java.net.SocketException;
+import java.nio.ByteBuffer;
+import java.nio.ByteOrder;
+import java.util.StringJoiner;
+
+
+/**
+ * IpNeighborMonitor.
+ *
+ * Monitors the kernel rtnetlink neighbor notifications and presents to callers
+ * NeighborEvents describing each event. Callers can provide a consumer instance
+ * to both filter (e.g. by interface index and IP address) and handle the
+ * generated NeighborEvents.
+ *
+ * @hide
+ */
+public class IpNeighborMonitor extends PacketReader {
+ private static final String TAG = IpNeighborMonitor.class.getSimpleName();
+ private static final boolean DBG = false;
+ private static final boolean VDBG = false;
+
+ /**
+ * Make the kernel perform neighbor reachability detection (IPv4 ARP or IPv6 ND)
+ * for the given IP address on the specified interface index.
+ *
+ * @return 0 if the request was successfully passed to the kernel; otherwise return
+ * a non-zero error code.
+ */
+ public static int startKernelNeighborProbe(int ifIndex, InetAddress ip) {
+ final String msgSnippet = "probing ip=" + ip.getHostAddress() + "%" + ifIndex;
+ if (DBG) { Log.d(TAG, msgSnippet); }
+
+ final byte[] msg = RtNetlinkNeighborMessage.newNewNeighborMessage(
+ 1, ip, StructNdMsg.NUD_PROBE, ifIndex, null);
+
+ try {
+ NetlinkSocket.sendOneShotKernelMessage(NETLINK_ROUTE, msg);
+ } catch (ErrnoException e) {
+ Log.e(TAG, "Error " + msgSnippet + ": " + e);
+ return -e.errno;
+ }
+
+ return 0;
+ }
+
+ public static class NeighborEvent {
+ final long elapsedMs;
+ final short msgType;
+ final int ifindex;
+ final InetAddress ip;
+ final short nudState;
+ final MacAddress macAddr;
+
+ public NeighborEvent(long elapsedMs, short msgType, int ifindex, InetAddress ip,
+ short nudState, MacAddress macAddr) {
+ this.elapsedMs = elapsedMs;
+ this.msgType = msgType;
+ this.ifindex = ifindex;
+ this.ip = ip;
+ this.nudState = nudState;
+ this.macAddr = macAddr;
+ }
+
+ boolean isConnected() {
+ return (msgType != RTM_DELNEIGH) && StructNdMsg.isNudStateConnected(nudState);
+ }
+
+ boolean isValid() {
+ return (msgType != RTM_DELNEIGH) && StructNdMsg.isNudStateValid(nudState);
+ }
+
+ @Override
+ public String toString() {
+ final StringJoiner j = new StringJoiner(",", "NeighborEvent{", "}");
+ return j.add("@" + elapsedMs)
+ .add(stringForNlMsgType(msgType))
+ .add("if=" + ifindex)
+ .add(ip.getHostAddress())
+ .add(StructNdMsg.stringForNudState(nudState))
+ .add("[" + macAddr + "]")
+ .toString();
+ }
+ }
+
+ // TODO: move NetworkStackUtils.closeSocketQuietly to somewhere accessible to this file.
+ private void closeSocketQuietly(FileDescriptor fd) {
+ try {
+ SocketUtils.closeSocket(fd);
+ } catch (IOException ignored) {
+ }
+ }
+
+ public interface NeighborEventConsumer {
+ // Every neighbor event received on the netlink socket is passed in
+ // here. Subclasses should filter for events of interest.
+ public void accept(NeighborEvent event);
+ }
+
+ private final SharedLog mLog;
+ private final NeighborEventConsumer mConsumer;
+
+ public IpNeighborMonitor(Handler h, SharedLog log, NeighborEventConsumer cb) {
+ super(h, NetlinkSocket.DEFAULT_RECV_BUFSIZE);
+ mLog = log.forSubComponent(TAG);
+ mConsumer = (cb != null) ? cb : (event) -> { /* discard */ };
+ }
+
+ @Override
+ protected FileDescriptor createFd() {
+ FileDescriptor fd = null;
+
+ try {
+ fd = Os.socket(AF_NETLINK, SOCK_DGRAM | SOCK_NONBLOCK, NETLINK_ROUTE);
+ Os.bind(fd, makeNetlinkSocketAddress(0, OsConstants.RTMGRP_NEIGH));
+ NetlinkSocket.connectToKernel(fd);
+
+ if (VDBG) {
+ final SocketAddress nlAddr = Os.getsockname(fd);
+ Log.d(TAG, "bound to sockaddr_nl{" + nlAddr.toString() + "}");
+ }
+ } catch (ErrnoException|SocketException e) {
+ logError("Failed to create rtnetlink socket", e);
+ closeSocketQuietly(fd);
+ return null;
+ }
+
+ return fd;
+ }
+
+ @Override
+ protected void handlePacket(byte[] recvbuf, int length) {
+ final long whenMs = SystemClock.elapsedRealtime();
+
+ final ByteBuffer byteBuffer = ByteBuffer.wrap(recvbuf, 0, length);
+ byteBuffer.order(ByteOrder.nativeOrder());
+
+ parseNetlinkMessageBuffer(byteBuffer, whenMs);
+ }
+
+ private void parseNetlinkMessageBuffer(ByteBuffer byteBuffer, long whenMs) {
+ while (byteBuffer.remaining() > 0) {
+ final int position = byteBuffer.position();
+ final NetlinkMessage nlMsg = NetlinkMessage.parse(byteBuffer);
+ if (nlMsg == null || nlMsg.getHeader() == null) {
+ byteBuffer.position(position);
+ mLog.e("unparsable netlink msg: " + hexify(byteBuffer));
+ break;
+ }
+
+ if (nlMsg instanceof NetlinkErrorMessage) {
+ mLog.e("netlink error: " + nlMsg);
+ continue;
+ } else if (!(nlMsg instanceof RtNetlinkNeighborMessage)) {
+ mLog.i("non-rtnetlink neighbor msg: " + nlMsg);
+ continue;
+ }
+
+ evaluateRtNetlinkNeighborMessage((RtNetlinkNeighborMessage) nlMsg, whenMs);
+ }
+ }
+
+ private void evaluateRtNetlinkNeighborMessage(
+ RtNetlinkNeighborMessage neighMsg, long whenMs) {
+ final short msgType = neighMsg.getHeader().nlmsg_type;
+ final StructNdMsg ndMsg = neighMsg.getNdHeader();
+ if (ndMsg == null) {
+ mLog.e("RtNetlinkNeighborMessage without ND message header!");
+ return;
+ }
+
+ final int ifindex = ndMsg.ndm_ifindex;
+ final InetAddress destination = neighMsg.getDestination();
+ final short nudState =
+ (msgType == RTM_DELNEIGH)
+ ? StructNdMsg.NUD_NONE
+ : ndMsg.ndm_state;
+
+ final NeighborEvent event = new NeighborEvent(
+ whenMs, msgType, ifindex, destination, nudState,
+ getMacAddress(neighMsg.getLinkLayerAddress()));
+
+ if (VDBG) {
+ Log.d(TAG, neighMsg.toString());
+ }
+ if (DBG) {
+ Log.d(TAG, event.toString());
+ }
+
+ mConsumer.accept(event);
+ }
+
+ private static MacAddress getMacAddress(byte[] linkLayerAddress) {
+ if (linkLayerAddress != null) {
+ try {
+ return MacAddress.fromBytes(linkLayerAddress);
+ } catch (IllegalArgumentException e) {
+ Log.e(TAG, "Failed to parse link-layer address: " + hexify(linkLayerAddress));
+ }
+ }
+
+ return null;
+ }
+}
diff --git a/common/moduleutils/src/android/net/util/FdEventsReader.java b/common/moduleutils/src/android/net/util/FdEventsReader.java
new file mode 100644
index 0000000..5a1154f
--- /dev/null
+++ b/common/moduleutils/src/android/net/util/FdEventsReader.java
@@ -0,0 +1,259 @@
+/*
+ * Copyright (C) 2016 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.util;
+
+import static android.os.MessageQueue.OnFileDescriptorEventListener.EVENT_ERROR;
+import static android.os.MessageQueue.OnFileDescriptorEventListener.EVENT_INPUT;
+
+import android.os.Handler;
+import android.os.Looper;
+import android.os.MessageQueue;
+import android.system.ErrnoException;
+import android.system.OsConstants;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+
+import java.io.FileDescriptor;
+import java.io.IOException;
+
+
+/**
+ * This class encapsulates the mechanics of registering a file descriptor
+ * with a thread's Looper and handling read events (and errors).
+ *
+ * Subclasses MUST implement createFd() and SHOULD override handlePacket(). They MAY override
+ * onStop() and onStart().
+ *
+ * Subclasses can expect a call life-cycle like the following:
+ *
+ * [1] when a client calls start(), createFd() is called, followed by the onStart() hook if all
+ * goes well. Implementations may override onStart() for additional initialization.
+ *
+ * [2] yield, waiting for read event or error notification:
+ *
+ * [a] readPacket() && handlePacket()
+ *
+ * [b] if (no error):
+ * goto 2
+ * else:
+ * goto 3
+ *
+ * [3] when a client calls stop(), the onStop() hook is called (unless already stopped or never
+ * started). Implementations may override onStop() for additional cleanup.
+ *
+ * The packet receive buffer is recycled on every read call, so subclasses
+ * should make any copies they would like inside their handlePacket()
+ * implementation.
+ *
+ * All public methods MUST only be called from the same thread with which
+ * the Handler constructor argument is associated.
+ *
+ * @param <BufferType> the type of the buffer used to read data.
+ */
+public abstract class FdEventsReader<BufferType> {
+ private static final int FD_EVENTS = EVENT_INPUT | EVENT_ERROR;
+ private static final int UNREGISTER_THIS_FD = 0;
+
+ @NonNull
+ private final Handler mHandler;
+ @NonNull
+ private final MessageQueue mQueue;
+ @NonNull
+ private final BufferType mBuffer;
+ @Nullable
+ private FileDescriptor mFd;
+ private long mPacketsReceived;
+
+ protected static void closeFd(FileDescriptor fd) {
+ try {
+ SocketUtils.closeSocket(fd);
+ } catch (IOException ignored) {
+ }
+ }
+
+ protected FdEventsReader(@NonNull Handler h, @NonNull BufferType buffer) {
+ mHandler = h;
+ mQueue = mHandler.getLooper().getQueue();
+ mBuffer = buffer;
+ }
+
+ /** Start this FdEventsReader. */
+ public boolean start() {
+ if (!onCorrectThread()) {
+ throw new IllegalStateException("start() called from off-thread");
+ }
+
+ return createAndRegisterFd();
+ }
+
+ /** Stop this FdEventsReader and destroy the file descriptor. */
+ public void stop() {
+ if (!onCorrectThread()) {
+ throw new IllegalStateException("stop() called from off-thread");
+ }
+
+ unregisterAndDestroyFd();
+ }
+
+ @NonNull
+ public Handler getHandler() {
+ return mHandler;
+ }
+
+ protected abstract int recvBufSize(@NonNull BufferType buffer);
+
+ /** Returns the size of the receive buffer. */
+ public int recvBufSize() {
+ return recvBufSize(mBuffer);
+ }
+
+ /**
+ * Get the number of successful calls to {@link #readPacket(FileDescriptor, Object)}.
+ *
+ * <p>A call was successful if {@link #readPacket(FileDescriptor, Object)} returned a value > 0.
+ */
+ public final long numPacketsReceived() {
+ return mPacketsReceived;
+ }
+
+ /**
+ * Subclasses MUST create the listening socket here, including setting all desired socket
+ * options, interface or address/port binding, etc. The socket MUST be created nonblocking.
+ */
+ @Nullable
+ protected abstract FileDescriptor createFd();
+
+ /**
+ * Implementations MUST return the bytes read or throw an Exception.
+ *
+ * <p>The caller may throw a {@link ErrnoException} with {@link OsConstants#EAGAIN} or
+ * {@link OsConstants#EINTR}, in which case {@link FdEventsReader} will ignore the buffer
+ * contents and respectively wait for further input or retry the read immediately. For all other
+ * exceptions, the {@link FdEventsReader} will be stopped with no more interactions with this
+ * method.
+ */
+ protected abstract int readPacket(@NonNull FileDescriptor fd, @NonNull BufferType buffer)
+ throws Exception;
+
+ /**
+ * Called by the main loop for every packet. Any desired copies of
+ * |recvbuf| should be made in here, as the underlying byte array is
+ * reused across all reads.
+ */
+ protected void handlePacket(@NonNull BufferType recvbuf, int length) {}
+
+ /**
+ * Called by the main loop to log errors. In some cases |e| may be null.
+ */
+ protected void logError(@NonNull String msg, @Nullable Exception e) {}
+
+ /**
+ * Called by start(), if successful, just prior to returning.
+ */
+ protected void onStart() {}
+
+ /**
+ * Called by stop() just prior to returning.
+ */
+ protected void onStop() {}
+
+ private boolean createAndRegisterFd() {
+ if (mFd != null) return true;
+
+ try {
+ mFd = createFd();
+ } catch (Exception e) {
+ logError("Failed to create socket: ", e);
+ closeFd(mFd);
+ mFd = null;
+ }
+
+ if (mFd == null) return false;
+
+ mQueue.addOnFileDescriptorEventListener(
+ mFd,
+ FD_EVENTS,
+ (fd, events) -> {
+ // Always call handleInput() so read/recvfrom are given
+ // a proper chance to encounter a meaningful errno and
+ // perhaps log a useful error message.
+ if (!isRunning() || !handleInput()) {
+ unregisterAndDestroyFd();
+ return UNREGISTER_THIS_FD;
+ }
+ return FD_EVENTS;
+ });
+ onStart();
+ return true;
+ }
+
+ private boolean isRunning() {
+ return (mFd != null) && mFd.valid();
+ }
+
+ // Keep trying to read until we get EAGAIN/EWOULDBLOCK or some fatal error.
+ private boolean handleInput() {
+ while (isRunning()) {
+ final int bytesRead;
+
+ try {
+ bytesRead = readPacket(mFd, mBuffer);
+ if (bytesRead < 1) {
+ if (isRunning()) logError("Socket closed, exiting", null);
+ break;
+ }
+ mPacketsReceived++;
+ } catch (ErrnoException e) {
+ if (e.errno == OsConstants.EAGAIN) {
+ // We've read everything there is to read this time around.
+ return true;
+ } else if (e.errno == OsConstants.EINTR) {
+ continue;
+ } else {
+ if (isRunning()) logError("readPacket error: ", e);
+ break;
+ }
+ } catch (Exception e) {
+ if (isRunning()) logError("readPacket error: ", e);
+ break;
+ }
+
+ try {
+ handlePacket(mBuffer, bytesRead);
+ } catch (Exception e) {
+ logError("handlePacket error: ", e);
+ break;
+ }
+ }
+
+ return false;
+ }
+
+ private void unregisterAndDestroyFd() {
+ if (mFd == null) return;
+
+ mQueue.removeOnFileDescriptorEventListener(mFd);
+ closeFd(mFd);
+ mFd = null;
+ onStop();
+ }
+
+ private boolean onCorrectThread() {
+ return (mHandler.getLooper() == Looper.myLooper());
+ }
+}
diff --git a/common/moduleutils/src/android/net/util/PacketReader.java b/common/moduleutils/src/android/net/util/PacketReader.java
new file mode 100644
index 0000000..0be7187
--- /dev/null
+++ b/common/moduleutils/src/android/net/util/PacketReader.java
@@ -0,0 +1,59 @@
+/*
+ * Copyright (C) 2018 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.util;
+
+import static java.lang.Math.max;
+
+import android.os.Handler;
+import android.system.Os;
+
+import java.io.FileDescriptor;
+
+/**
+ * Specialization of {@link FdEventsReader} that reads packets into a byte array.
+ *
+ * TODO: rename this class to something more correctly descriptive (something
+ * like [or less horrible than] FdReadEventsHandler?).
+ */
+public abstract class PacketReader extends FdEventsReader<byte[]> {
+
+ public static final int DEFAULT_RECV_BUF_SIZE = 2 * 1024;
+
+ protected PacketReader(Handler h) {
+ this(h, DEFAULT_RECV_BUF_SIZE);
+ }
+
+ protected PacketReader(Handler h, int recvBufSize) {
+ super(h, new byte[max(recvBufSize, DEFAULT_RECV_BUF_SIZE)]);
+ }
+
+ @Override
+ protected final int recvBufSize(byte[] buffer) {
+ return buffer.length;
+ }
+
+ /**
+ * Subclasses MAY override this to change the default read() implementation
+ * in favour of, say, recvfrom().
+ *
+ * Implementations MUST return the bytes read or throw an Exception.
+ */
+ @Override
+ protected int readPacket(FileDescriptor fd, byte[] packetBuffer) throws Exception {
+ return Os.read(fd, packetBuffer, 0, packetBuffer.length);
+ }
+}