| /* |
| * 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_RDNSS; |
| |
| import android.net.InetAddresses; |
| |
| 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.net.Inet6Address; |
| import java.nio.ByteBuffer; |
| |
| /** |
| * IPv6 RA recursive DNS server option, as per https://tools.ietf.org/html/rfc8106. |
| * This should be followed by a series of DNSv6 server addresses. |
| * |
| * 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 | Reserved | |
| * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| * | Lifetime | |
| * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| * | | |
| * : Addresses of IPv6 Recursive DNS Servers : |
| * | | |
| * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| */ |
| public class RdnssOption 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.S16) |
| public final short reserved; |
| @Field(order = 3, type = Type.U32) |
| public final long lifetime; |
| |
| public RdnssOption(final byte type, final byte length, final short reserved, |
| final long lifetime) { |
| this.type = type; |
| this.length = length; |
| this.reserved = reserved; |
| this.lifetime = lifetime; |
| } |
| |
| /** |
| * Build a RDNSS option from the required specified Inet6Address parameters. |
| */ |
| public static ByteBuffer build(final long lifetime, final Inet6Address... servers) { |
| final byte length = (byte) (1 + 2 * servers.length); |
| final RdnssOption option = new RdnssOption((byte) ICMPV6_ND_OPTION_RDNSS, |
| length, (short) 0, lifetime); |
| final ByteBuffer buffer = ByteBuffer.allocate(length * 8); |
| option.writeToByteBuffer(buffer); |
| for (Inet6Address server : servers) { |
| buffer.put(server.getAddress()); |
| } |
| buffer.flip(); |
| return buffer; |
| } |
| |
| /** |
| * Build a RDNSS option from the required specified String parameters. |
| * |
| * @throws IllegalArgumentException if {@code servers} does not contain only numeric addresses. |
| */ |
| public static ByteBuffer build(final long lifetime, final String... servers) { |
| final Inet6Address[] serverArray = new Inet6Address[servers.length]; |
| for (int i = 0; i < servers.length; i++) { |
| serverArray[i] = (Inet6Address) InetAddresses.parseNumericAddress(servers[i]); |
| } |
| return build(lifetime, serverArray); |
| } |
| } |