EdnsClientSubnetTest.java

package io.netty.resolver.dns;

import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.AddressedEnvelope;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.nio.NioDatagramChannel;
import io.netty.handler.codec.dns.*;
import io.netty.util.concurrent.Future;
import io.netty.util.internal.StringUtil;
import scala.Array;

import java.net.InetSocketAddress;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.TimeUnit;

import io.netty.handler.codec.dns.DefaultDnsRawRecord;
import io.netty.handler.codec.dns.DnsRecordType;

public class EdnsClientSubnetTest {


    public static int MAX_PAYLOAD_SIZE = 4096;
    public static final DnsRecordType EDNS_CLIENT_SUBNET_CODE = new DnsRecordType(0x0008, "CSUBNET"); // old code: 0x50fa newer code should be 0x0008

    // http://www.iana.org/assignments/address-family-numbers/address-family-numbers.xhtml
    public static byte IPv4_FAMILY = 1;
    public static byte IPv6_FAMILY = 2;

    /**
     * http://tools.ietf.org/html/draft-vandergaast-edns-client-subnet-02
     */
    static class EdnsClientSubnet extends DefaultDnsRawRecord {

        public EdnsClientSubnet(ByteBuf content) {
            super(StringUtil.EMPTY_STRING, DnsRecordType.OPT, MAX_PAYLOAD_SIZE, 0, content);
        }

    }

    public static EdnsClientSubnet buildEDnsClientSubnetRecord(int sourceNetMask, byte[] address) {
        byte family;

        if (address == null)
            throw new IllegalArgumentException("address");

        if (sourceNetMask < 0)
            throw new IllegalArgumentException("invalid net mask");

        if (address.length == 4) {
            family = IPv4_FAMILY;
            if (sourceNetMask > 32)
                throw new IllegalArgumentException("invalid net mask");
        } else if (address.length == 16) {
            family = IPv6_FAMILY;
            if (sourceNetMask > 128)
                throw new IllegalArgumentException("invalid net mask");
        } else {
            throw new IllegalArgumentException("undefined address family");
        }

        /**
         *                 +0 (MSB)                            +1 (LSB)
         *     +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
         *  0: |                          OPTION-CODE                          |
         *     +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
         *  2: |                         OPTION-LENGTH                         |
         *     +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
         *  4: |                            FAMILY                             |
         *     +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
         *  6: |          SOURCE NETMASK       |        SCOPE NETMASK          |
         *     +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
         *  7: |                           ADDRESS...                          /
         *     +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
         *
         */
        byte[] buf = new byte[8 + address.length];
        buf[0] = (byte) ((EDNS_CLIENT_SUBNET_CODE.intValue() >> 8) & 0xff);
        buf[1] = (byte) (EDNS_CLIENT_SUBNET_CODE.intValue() & 0xff);
        buf[3] = (byte) (4 + address.length);
        buf[5] = family;
        buf[6] = (byte) sourceNetMask;
        Array.copy(address, 0, buf, 8, address.length);

        return new EdnsClientSubnet(Unpooled.wrappedBuffer(buf));
    }

    public static int DNSPort = 53;
    public static void main(String[] args) throws ExecutionException, InterruptedException {
        EventLoopGroup group = new NioEventLoopGroup(1);

        DnsServerAddresses nameServerAddresses = DnsServerAddresses.rotational(
                new InetSocketAddress("prg18.ff.avast.com", DNSPort)
        );

        DnsNameResolver resolver = new DnsNameResolverBuilder(group.next())
                .channelType(NioDatagramChannel.class)
                .nameServerAddresses(nameServerAddresses )
                .queryTimeoutMillis(TimeUnit.HOURS.toMillis(1))
                .build();

        DefaultDnsQuestion q = new DefaultDnsQuestion("su.ff.avast.com", DnsRecordType.A, DnsRecord.CLASS_IN);
        EdnsClientSubnet a = buildEDnsClientSubnetRecord(32, new byte[]{103, (byte) 240, (byte) 252, 0});


        Future<AddressedEnvelope<DnsResponse, InetSocketAddress>> f = resolver.query(
                q,
                java.util.Collections.<DnsRecord>singletonList(a));

        AddressedEnvelope<DnsResponse, InetSocketAddress> res = f.get();
        System.out.println(res);
        resolver.close();
    }
}