Erik Kline | 84714bf | 2017-05-19 09:29:48 +0900 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2017 The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | package android.net.ip; |
| 18 | |
Erik Kline | 8bd00d5 | 2017-12-08 17:47:50 +0900 | [diff] [blame] | 19 | import static android.net.netlink.NetlinkConstants.RTM_DELNEIGH; |
Remi NGUYEN VAN | e7e9f2b | 2019-01-18 19:05:29 +0900 | [diff] [blame] | 20 | import static android.net.netlink.NetlinkConstants.hexify; |
Erik Kline | 8bd00d5 | 2017-12-08 17:47:50 +0900 | [diff] [blame] | 21 | import static android.net.netlink.NetlinkConstants.stringForNlMsgType; |
Remi NGUYEN VAN | 811f638 | 2019-01-20 12:08:21 +0900 | [diff] [blame] | 22 | import static android.net.util.SocketUtils.makeNetlinkSocketAddress; |
Remi NGUYEN VAN | 231b52b | 2019-01-29 15:38:52 +0900 | [diff] [blame] | 23 | import static android.system.OsConstants.AF_NETLINK; |
| 24 | import static android.system.OsConstants.NETLINK_ROUTE; |
| 25 | import static android.system.OsConstants.SOCK_DGRAM; |
| 26 | import static android.system.OsConstants.SOCK_NONBLOCK; |
Erik Kline | 8bd00d5 | 2017-12-08 17:47:50 +0900 | [diff] [blame] | 27 | |
| 28 | import android.net.MacAddress; |
Erik Kline | 84714bf | 2017-05-19 09:29:48 +0900 | [diff] [blame] | 29 | import android.net.netlink.NetlinkErrorMessage; |
| 30 | import android.net.netlink.NetlinkMessage; |
| 31 | import android.net.netlink.NetlinkSocket; |
| 32 | import android.net.netlink.RtNetlinkNeighborMessage; |
| 33 | import android.net.netlink.StructNdMsg; |
Remi NGUYEN VAN | 231b52b | 2019-01-29 15:38:52 +0900 | [diff] [blame] | 34 | import android.net.util.NetworkStackUtils; |
Erik Kline | 84714bf | 2017-05-19 09:29:48 +0900 | [diff] [blame] | 35 | import android.net.util.PacketReader; |
| 36 | import android.net.util.SharedLog; |
Remi NGUYEN VAN | 231b52b | 2019-01-29 15:38:52 +0900 | [diff] [blame] | 37 | import android.net.util.SocketUtils; |
Erik Kline | 84714bf | 2017-05-19 09:29:48 +0900 | [diff] [blame] | 38 | import android.os.Handler; |
| 39 | import android.os.SystemClock; |
| 40 | import android.system.ErrnoException; |
Erik Kline | 84714bf | 2017-05-19 09:29:48 +0900 | [diff] [blame] | 41 | import android.system.Os; |
| 42 | import android.system.OsConstants; |
| 43 | import android.util.Log; |
| 44 | |
Erik Kline | 84714bf | 2017-05-19 09:29:48 +0900 | [diff] [blame] | 45 | import java.io.FileDescriptor; |
| 46 | import java.net.InetAddress; |
| 47 | import java.net.SocketAddress; |
| 48 | import java.net.SocketException; |
| 49 | import java.nio.ByteBuffer; |
| 50 | import java.nio.ByteOrder; |
| 51 | import java.util.StringJoiner; |
| 52 | |
| 53 | |
| 54 | /** |
| 55 | * IpNeighborMonitor. |
| 56 | * |
| 57 | * Monitors the kernel rtnetlink neighbor notifications and presents to callers |
| 58 | * NeighborEvents describing each event. Callers can provide a consumer instance |
| 59 | * to both filter (e.g. by interface index and IP address) and handle the |
| 60 | * generated NeighborEvents. |
| 61 | * |
| 62 | * @hide |
| 63 | */ |
| 64 | public class IpNeighborMonitor extends PacketReader { |
| 65 | private static final String TAG = IpNeighborMonitor.class.getSimpleName(); |
| 66 | private static final boolean DBG = false; |
| 67 | private static final boolean VDBG = false; |
| 68 | |
| 69 | /** |
| 70 | * Make the kernel perform neighbor reachability detection (IPv4 ARP or IPv6 ND) |
| 71 | * for the given IP address on the specified interface index. |
| 72 | * |
| 73 | * @return 0 if the request was successfully passed to the kernel; otherwise return |
| 74 | * a non-zero error code. |
| 75 | */ |
| 76 | public static int startKernelNeighborProbe(int ifIndex, InetAddress ip) { |
| 77 | final String msgSnippet = "probing ip=" + ip.getHostAddress() + "%" + ifIndex; |
| 78 | if (DBG) { Log.d(TAG, msgSnippet); } |
| 79 | |
| 80 | final byte[] msg = RtNetlinkNeighborMessage.newNewNeighborMessage( |
| 81 | 1, ip, StructNdMsg.NUD_PROBE, ifIndex, null); |
| 82 | |
| 83 | try { |
Remi NGUYEN VAN | 231b52b | 2019-01-29 15:38:52 +0900 | [diff] [blame] | 84 | NetlinkSocket.sendOneShotKernelMessage(NETLINK_ROUTE, msg); |
Erik Kline | 84714bf | 2017-05-19 09:29:48 +0900 | [diff] [blame] | 85 | } catch (ErrnoException e) { |
| 86 | Log.e(TAG, "Error " + msgSnippet + ": " + e); |
| 87 | return -e.errno; |
| 88 | } |
| 89 | |
| 90 | return 0; |
| 91 | } |
| 92 | |
| 93 | public static class NeighborEvent { |
| 94 | final long elapsedMs; |
| 95 | final short msgType; |
| 96 | final int ifindex; |
| 97 | final InetAddress ip; |
| 98 | final short nudState; |
Erik Kline | 8bd00d5 | 2017-12-08 17:47:50 +0900 | [diff] [blame] | 99 | final MacAddress macAddr; |
Erik Kline | 84714bf | 2017-05-19 09:29:48 +0900 | [diff] [blame] | 100 | |
| 101 | public NeighborEvent(long elapsedMs, short msgType, int ifindex, InetAddress ip, |
Erik Kline | 8bd00d5 | 2017-12-08 17:47:50 +0900 | [diff] [blame] | 102 | short nudState, MacAddress macAddr) { |
Erik Kline | 84714bf | 2017-05-19 09:29:48 +0900 | [diff] [blame] | 103 | this.elapsedMs = elapsedMs; |
| 104 | this.msgType = msgType; |
| 105 | this.ifindex = ifindex; |
| 106 | this.ip = ip; |
| 107 | this.nudState = nudState; |
Erik Kline | 8bd00d5 | 2017-12-08 17:47:50 +0900 | [diff] [blame] | 108 | this.macAddr = macAddr; |
Erik Kline | 84714bf | 2017-05-19 09:29:48 +0900 | [diff] [blame] | 109 | } |
| 110 | |
| 111 | boolean isConnected() { |
Erik Kline | 8bd00d5 | 2017-12-08 17:47:50 +0900 | [diff] [blame] | 112 | return (msgType != RTM_DELNEIGH) && StructNdMsg.isNudStateConnected(nudState); |
Erik Kline | 84714bf | 2017-05-19 09:29:48 +0900 | [diff] [blame] | 113 | } |
| 114 | |
| 115 | boolean isValid() { |
Erik Kline | 8bd00d5 | 2017-12-08 17:47:50 +0900 | [diff] [blame] | 116 | return (msgType != RTM_DELNEIGH) && StructNdMsg.isNudStateValid(nudState); |
Erik Kline | 84714bf | 2017-05-19 09:29:48 +0900 | [diff] [blame] | 117 | } |
| 118 | |
| 119 | @Override |
| 120 | public String toString() { |
| 121 | final StringJoiner j = new StringJoiner(",", "NeighborEvent{", "}"); |
| 122 | return j.add("@" + elapsedMs) |
Erik Kline | 8bd00d5 | 2017-12-08 17:47:50 +0900 | [diff] [blame] | 123 | .add(stringForNlMsgType(msgType)) |
Erik Kline | 84714bf | 2017-05-19 09:29:48 +0900 | [diff] [blame] | 124 | .add("if=" + ifindex) |
| 125 | .add(ip.getHostAddress()) |
| 126 | .add(StructNdMsg.stringForNudState(nudState)) |
Erik Kline | 8bd00d5 | 2017-12-08 17:47:50 +0900 | [diff] [blame] | 127 | .add("[" + macAddr + "]") |
Erik Kline | 84714bf | 2017-05-19 09:29:48 +0900 | [diff] [blame] | 128 | .toString(); |
| 129 | } |
| 130 | } |
| 131 | |
| 132 | public interface NeighborEventConsumer { |
| 133 | // Every neighbor event received on the netlink socket is passed in |
| 134 | // here. Subclasses should filter for events of interest. |
| 135 | public void accept(NeighborEvent event); |
| 136 | } |
| 137 | |
| 138 | private final SharedLog mLog; |
| 139 | private final NeighborEventConsumer mConsumer; |
| 140 | |
| 141 | public IpNeighborMonitor(Handler h, SharedLog log, NeighborEventConsumer cb) { |
| 142 | super(h, NetlinkSocket.DEFAULT_RECV_BUFSIZE); |
| 143 | mLog = log.forSubComponent(TAG); |
| 144 | mConsumer = (cb != null) ? cb : (event) -> { /* discard */ }; |
| 145 | } |
| 146 | |
| 147 | @Override |
| 148 | protected FileDescriptor createFd() { |
| 149 | FileDescriptor fd = null; |
| 150 | |
| 151 | try { |
Remi NGUYEN VAN | 231b52b | 2019-01-29 15:38:52 +0900 | [diff] [blame] | 152 | fd = Os.socket(AF_NETLINK, SOCK_DGRAM | SOCK_NONBLOCK, NETLINK_ROUTE); |
| 153 | SocketUtils.bindSocket(fd, makeNetlinkSocketAddress(0, OsConstants.RTMGRP_NEIGH)); |
Remi NGUYEN VAN | 811f638 | 2019-01-20 12:08:21 +0900 | [diff] [blame] | 154 | NetlinkSocket.connectToKernel(fd); |
Erik Kline | 84714bf | 2017-05-19 09:29:48 +0900 | [diff] [blame] | 155 | |
| 156 | if (VDBG) { |
Remi NGUYEN VAN | 811f638 | 2019-01-20 12:08:21 +0900 | [diff] [blame] | 157 | final SocketAddress nlAddr = Os.getsockname(fd); |
| 158 | Log.d(TAG, "bound to sockaddr_nl{" + nlAddr.toString() + "}"); |
Erik Kline | 84714bf | 2017-05-19 09:29:48 +0900 | [diff] [blame] | 159 | } |
| 160 | } catch (ErrnoException|SocketException e) { |
| 161 | logError("Failed to create rtnetlink socket", e); |
Remi NGUYEN VAN | 231b52b | 2019-01-29 15:38:52 +0900 | [diff] [blame] | 162 | NetworkStackUtils.closeSocketQuietly(fd); |
Erik Kline | 84714bf | 2017-05-19 09:29:48 +0900 | [diff] [blame] | 163 | return null; |
| 164 | } |
| 165 | |
| 166 | return fd; |
| 167 | } |
| 168 | |
| 169 | @Override |
| 170 | protected void handlePacket(byte[] recvbuf, int length) { |
| 171 | final long whenMs = SystemClock.elapsedRealtime(); |
| 172 | |
| 173 | final ByteBuffer byteBuffer = ByteBuffer.wrap(recvbuf, 0, length); |
| 174 | byteBuffer.order(ByteOrder.nativeOrder()); |
| 175 | |
| 176 | parseNetlinkMessageBuffer(byteBuffer, whenMs); |
| 177 | } |
| 178 | |
| 179 | private void parseNetlinkMessageBuffer(ByteBuffer byteBuffer, long whenMs) { |
| 180 | while (byteBuffer.remaining() > 0) { |
| 181 | final int position = byteBuffer.position(); |
| 182 | final NetlinkMessage nlMsg = NetlinkMessage.parse(byteBuffer); |
| 183 | if (nlMsg == null || nlMsg.getHeader() == null) { |
| 184 | byteBuffer.position(position); |
Erik Kline | 8bd00d5 | 2017-12-08 17:47:50 +0900 | [diff] [blame] | 185 | mLog.e("unparsable netlink msg: " + hexify(byteBuffer)); |
Erik Kline | 84714bf | 2017-05-19 09:29:48 +0900 | [diff] [blame] | 186 | break; |
| 187 | } |
| 188 | |
| 189 | final int srcPortId = nlMsg.getHeader().nlmsg_pid; |
| 190 | if (srcPortId != 0) { |
Remi NGUYEN VAN | 3ba6c0d | 2019-01-20 13:48:19 +0900 | [diff] [blame] | 191 | mLog.e("non-kernel source portId: " + Integer.toUnsignedLong(srcPortId)); |
Erik Kline | 84714bf | 2017-05-19 09:29:48 +0900 | [diff] [blame] | 192 | break; |
| 193 | } |
| 194 | |
| 195 | if (nlMsg instanceof NetlinkErrorMessage) { |
| 196 | mLog.e("netlink error: " + nlMsg); |
| 197 | continue; |
| 198 | } else if (!(nlMsg instanceof RtNetlinkNeighborMessage)) { |
| 199 | mLog.i("non-rtnetlink neighbor msg: " + nlMsg); |
| 200 | continue; |
| 201 | } |
| 202 | |
| 203 | evaluateRtNetlinkNeighborMessage((RtNetlinkNeighborMessage) nlMsg, whenMs); |
| 204 | } |
| 205 | } |
| 206 | |
| 207 | private void evaluateRtNetlinkNeighborMessage( |
| 208 | RtNetlinkNeighborMessage neighMsg, long whenMs) { |
| 209 | final short msgType = neighMsg.getHeader().nlmsg_type; |
| 210 | final StructNdMsg ndMsg = neighMsg.getNdHeader(); |
| 211 | if (ndMsg == null) { |
| 212 | mLog.e("RtNetlinkNeighborMessage without ND message header!"); |
| 213 | return; |
| 214 | } |
| 215 | |
| 216 | final int ifindex = ndMsg.ndm_ifindex; |
| 217 | final InetAddress destination = neighMsg.getDestination(); |
| 218 | final short nudState = |
Erik Kline | 8bd00d5 | 2017-12-08 17:47:50 +0900 | [diff] [blame] | 219 | (msgType == RTM_DELNEIGH) |
Erik Kline | 84714bf | 2017-05-19 09:29:48 +0900 | [diff] [blame] | 220 | ? StructNdMsg.NUD_NONE |
| 221 | : ndMsg.ndm_state; |
| 222 | |
| 223 | final NeighborEvent event = new NeighborEvent( |
Erik Kline | 8bd00d5 | 2017-12-08 17:47:50 +0900 | [diff] [blame] | 224 | whenMs, msgType, ifindex, destination, nudState, |
| 225 | getMacAddress(neighMsg.getLinkLayerAddress())); |
Erik Kline | 84714bf | 2017-05-19 09:29:48 +0900 | [diff] [blame] | 226 | |
| 227 | if (VDBG) { |
| 228 | Log.d(TAG, neighMsg.toString()); |
| 229 | } |
| 230 | if (DBG) { |
| 231 | Log.d(TAG, event.toString()); |
| 232 | } |
| 233 | |
| 234 | mConsumer.accept(event); |
| 235 | } |
Erik Kline | 8bd00d5 | 2017-12-08 17:47:50 +0900 | [diff] [blame] | 236 | |
| 237 | private static MacAddress getMacAddress(byte[] linkLayerAddress) { |
| 238 | if (linkLayerAddress != null) { |
| 239 | try { |
| 240 | return MacAddress.fromBytes(linkLayerAddress); |
| 241 | } catch (IllegalArgumentException e) { |
| 242 | Log.e(TAG, "Failed to parse link-layer address: " + hexify(linkLayerAddress)); |
| 243 | } |
| 244 | } |
| 245 | |
| 246 | return null; |
| 247 | } |
Erik Kline | 84714bf | 2017-05-19 09:29:48 +0900 | [diff] [blame] | 248 | } |