| /* |
| * Copyright (C) 2021 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 com.android.net.module.util.structs; |
| |
| import static com.android.net.module.util.NetworkStackConstants.ICMPV6_ND_OPTION_PIO; |
| |
| import android.annotation.NonNull; |
| import android.net.IpPrefix; |
| |
| import com.android.net.module.util.Struct; |
| import com.android.net.module.util.Struct.Field; |
| import com.android.net.module.util.Struct.Type; |
| |
| import java.nio.ByteBuffer; |
| import java.nio.ByteOrder; |
| |
| /** |
| * ICMPv6 prefix information option, as per https://tools.ietf.org/html/rfc4861. |
| * |
| * 0 1 2 3 |
| * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 |
| * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| * | Type | Length | Prefix Length |L|A| Reserved1 | |
| * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| * | Valid Lifetime | |
| * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| * | Preferred Lifetime | |
| * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| * | Reserved2 | |
| * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| * | | |
| * + + |
| * | | |
| * + Prefix + |
| * | | |
| * + + |
| * | | |
| * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| */ |
| public class PrefixInformationOption extends Struct { |
| @Field(order = 0, type = Type.S8) |
| public final byte type; |
| @Field(order = 1, type = Type.S8) |
| public final byte length; // Length in 8-byte units |
| @Field(order = 2, type = Type.S8) |
| public final byte prefixLen; |
| @Field(order = 3, type = Type.S8) |
| // On-link flag, Autonomous address configuration flag, 6-reserved bits |
| public final byte flags; |
| @Field(order = 4, type = Type.U32) |
| public final long validLifetime; |
| @Field(order = 5, type = Type.U32) |
| public final long preferredLifetime; |
| @Field(order = 6, type = Type.S32) |
| public final int reserved; |
| @Field(order = 7, type = Type.ByteArray, arraysize = 16) |
| public final byte[] prefix; |
| |
| PrefixInformationOption(final byte type, final byte length, final byte prefixLen, |
| final byte flags, final long validLifetime, final long preferredLifetime, |
| final int reserved, @NonNull final byte[] prefix) { |
| this.type = type; |
| this.length = length; |
| this.prefixLen = prefixLen; |
| this.flags = flags; |
| this.validLifetime = validLifetime; |
| this.preferredLifetime = preferredLifetime; |
| this.reserved = reserved; |
| this.prefix = prefix; |
| } |
| |
| /** |
| * Build a Prefix Information option from the required specified parameters. |
| */ |
| public static ByteBuffer build(final IpPrefix prefix, final byte flags, |
| final long validLifetime, final long preferredLifetime) { |
| final PrefixInformationOption option = new PrefixInformationOption( |
| (byte) ICMPV6_ND_OPTION_PIO, (byte) 4 /* option len */, |
| (byte) prefix.getPrefixLength(), flags, validLifetime, preferredLifetime, |
| (int) 0, prefix.getRawAddress()); |
| return ByteBuffer.wrap(option.writeToBytes(ByteOrder.BIG_ENDIAN)); |
| } |
| } |