junyulai | 0683511 | 2019-01-03 18:50:15 +0800 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2019 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; |
| 18 | |
markchien | 150e191 | 2018-12-27 22:49:51 +0800 | [diff] [blame] | 19 | import static android.net.SocketKeepalive.ERROR_INVALID_IP_ADDRESS; |
| 20 | import static android.net.SocketKeepalive.ERROR_INVALID_PORT; |
| 21 | |
junyulai | 0683511 | 2019-01-03 18:50:15 +0800 | [diff] [blame] | 22 | import android.net.util.IpUtils; |
junyulai | 02abbfd | 2019-06-03 17:51:41 +0800 | [diff] [blame] | 23 | import android.os.Parcel; |
Aaron Huang | 76985bd | 2019-04-23 22:17:16 +0800 | [diff] [blame] | 24 | import android.os.Parcelable; |
junyulai | 0683511 | 2019-01-03 18:50:15 +0800 | [diff] [blame] | 25 | import android.system.OsConstants; |
| 26 | |
| 27 | import java.net.Inet4Address; |
| 28 | import java.net.InetAddress; |
| 29 | import java.nio.ByteBuffer; |
| 30 | import java.nio.ByteOrder; |
| 31 | |
| 32 | /** @hide */ |
Aaron Huang | 76985bd | 2019-04-23 22:17:16 +0800 | [diff] [blame] | 33 | public final class NattKeepalivePacketData extends KeepalivePacketData implements Parcelable { |
Aaron Huang | 08d9ade | 2019-10-02 01:39:46 +0800 | [diff] [blame] | 34 | private static final int IPV4_HEADER_LENGTH = 20; |
| 35 | private static final int UDP_HEADER_LENGTH = 8; |
| 36 | |
junyulai | 0683511 | 2019-01-03 18:50:15 +0800 | [diff] [blame] | 37 | // This should only be constructed via static factory methods, such as |
| 38 | // nattKeepalivePacket |
| 39 | private NattKeepalivePacketData(InetAddress srcAddress, int srcPort, |
| 40 | InetAddress dstAddress, int dstPort, byte[] data) throws |
| 41 | InvalidPacketException { |
| 42 | super(srcAddress, srcPort, dstAddress, dstPort, data); |
| 43 | } |
| 44 | |
| 45 | /** |
| 46 | * Factory method to create Nat-T keepalive packet structure. |
| 47 | */ |
| 48 | public static NattKeepalivePacketData nattKeepalivePacket( |
| 49 | InetAddress srcAddress, int srcPort, InetAddress dstAddress, int dstPort) |
| 50 | throws InvalidPacketException { |
| 51 | |
| 52 | if (!(srcAddress instanceof Inet4Address) || !(dstAddress instanceof Inet4Address)) { |
markchien | 150e191 | 2018-12-27 22:49:51 +0800 | [diff] [blame] | 53 | throw new InvalidPacketException(ERROR_INVALID_IP_ADDRESS); |
junyulai | 0683511 | 2019-01-03 18:50:15 +0800 | [diff] [blame] | 54 | } |
| 55 | |
| 56 | if (dstPort != NattSocketKeepalive.NATT_PORT) { |
markchien | 150e191 | 2018-12-27 22:49:51 +0800 | [diff] [blame] | 57 | throw new InvalidPacketException(ERROR_INVALID_PORT); |
junyulai | 0683511 | 2019-01-03 18:50:15 +0800 | [diff] [blame] | 58 | } |
| 59 | |
| 60 | int length = IPV4_HEADER_LENGTH + UDP_HEADER_LENGTH + 1; |
| 61 | ByteBuffer buf = ByteBuffer.allocate(length); |
| 62 | buf.order(ByteOrder.BIG_ENDIAN); |
| 63 | buf.putShort((short) 0x4500); // IP version and TOS |
| 64 | buf.putShort((short) length); |
| 65 | buf.putInt(0); // ID, flags, offset |
| 66 | buf.put((byte) 64); // TTL |
| 67 | buf.put((byte) OsConstants.IPPROTO_UDP); |
| 68 | int ipChecksumOffset = buf.position(); |
| 69 | buf.putShort((short) 0); // IP checksum |
| 70 | buf.put(srcAddress.getAddress()); |
| 71 | buf.put(dstAddress.getAddress()); |
| 72 | buf.putShort((short) srcPort); |
| 73 | buf.putShort((short) dstPort); |
| 74 | buf.putShort((short) (length - 20)); // UDP length |
| 75 | int udpChecksumOffset = buf.position(); |
| 76 | buf.putShort((short) 0); // UDP checksum |
| 77 | buf.put((byte) 0xff); // NAT-T keepalive |
| 78 | buf.putShort(ipChecksumOffset, IpUtils.ipChecksum(buf, 0)); |
| 79 | buf.putShort(udpChecksumOffset, IpUtils.udpChecksum(buf, 0, IPV4_HEADER_LENGTH)); |
| 80 | |
| 81 | return new NattKeepalivePacketData(srcAddress, srcPort, dstAddress, dstPort, buf.array()); |
| 82 | } |
Aaron Huang | 76985bd | 2019-04-23 22:17:16 +0800 | [diff] [blame] | 83 | |
junyulai | 02abbfd | 2019-06-03 17:51:41 +0800 | [diff] [blame] | 84 | /** Parcelable Implementation */ |
| 85 | public int describeContents() { |
| 86 | return 0; |
Aaron Huang | 76985bd | 2019-04-23 22:17:16 +0800 | [diff] [blame] | 87 | } |
junyulai | 02abbfd | 2019-06-03 17:51:41 +0800 | [diff] [blame] | 88 | |
| 89 | /** Write to parcel */ |
| 90 | public void writeToParcel(Parcel out, int flags) { |
| 91 | out.writeString(srcAddress.getHostAddress()); |
| 92 | out.writeString(dstAddress.getHostAddress()); |
| 93 | out.writeInt(srcPort); |
| 94 | out.writeInt(dstPort); |
| 95 | } |
| 96 | |
| 97 | /** Parcelable Creator */ |
| 98 | public static final Parcelable.Creator<NattKeepalivePacketData> CREATOR = |
| 99 | new Parcelable.Creator<NattKeepalivePacketData>() { |
| 100 | public NattKeepalivePacketData createFromParcel(Parcel in) { |
| 101 | final InetAddress srcAddress = |
| 102 | InetAddresses.parseNumericAddress(in.readString()); |
| 103 | final InetAddress dstAddress = |
| 104 | InetAddresses.parseNumericAddress(in.readString()); |
| 105 | final int srcPort = in.readInt(); |
| 106 | final int dstPort = in.readInt(); |
| 107 | try { |
| 108 | return NattKeepalivePacketData.nattKeepalivePacket(srcAddress, srcPort, |
| 109 | dstAddress, dstPort); |
| 110 | } catch (InvalidPacketException e) { |
| 111 | throw new IllegalArgumentException( |
| 112 | "Invalid NAT-T keepalive data: " + e.error); |
| 113 | } |
| 114 | } |
| 115 | |
| 116 | public NattKeepalivePacketData[] newArray(int size) { |
| 117 | return new NattKeepalivePacketData[size]; |
| 118 | } |
| 119 | }; |
junyulai | 0683511 | 2019-01-03 18:50:15 +0800 | [diff] [blame] | 120 | } |