Example usage for io.netty.handler.codec.dns DnsResponse recordAt

Introduction

In this page you can find the example usage for io.netty.handler.codec.dns DnsResponse recordAt.

Prototype

<T extends DnsRecord> T recordAt(DnsSection section, int index);

Source Link

Document

Returns the record at the specified index of the specified section of this DNS message.

Usage

From source file:io.vertx.core.dns.impl.DnsClientImpl.java

License:Open Source License

@SuppressWarnings("unchecked")
private <T> void lookup(String name, Future<List<T>> result, DnsRecordType... types) {
    Objects.requireNonNull(name, "no null name accepted");
    bootstrap.connect(dnsServer).addListener(new RetryChannelFutureListener(result) {
        @Override//from   w w w .  j  a va  2s .c om
        public void onSuccess(ChannelFuture future) throws Exception {
            DatagramDnsQuery query = new DatagramDnsQuery(null, dnsServer,
                    ThreadLocalRandom.current().nextInt());
            for (DnsRecordType type : types) {
                query.addRecord(DnsSection.QUESTION, new DefaultDnsQuestion(name, type, DnsRecord.CLASS_IN));
            }
            future.channel().writeAndFlush(query).addListener(new RetryChannelFutureListener(result) {
                @Override
                public void onSuccess(ChannelFuture future) throws Exception {
                    future.channel().pipeline().addLast(new SimpleChannelInboundHandler<DnsResponse>() {
                        @Override
                        protected void channelRead0(ChannelHandlerContext ctx, DnsResponse msg)
                                throws Exception {
                            DnsResponseCode code = DnsResponseCode.valueOf(msg.code().intValue());

                            if (code == DnsResponseCode.NOERROR) {

                                int count = msg.count(DnsSection.ANSWER);

                                List<T> records = new ArrayList<>(count);
                                for (int idx = 0; idx < count; idx++) {
                                    DnsRecord a = msg.recordAt(DnsSection.ANSWER, idx);
                                    T record = RecordDecoder.decode(a);
                                    if (isRequestedType(a.type(), types)) {
                                        records.add(record);
                                    }
                                }

                                if (records.size() > 0 && (records.get(0) instanceof MxRecordImpl
                                        || records.get(0) instanceof SrvRecordImpl)) {
                                    Collections.sort((List) records);
                                }

                                setResult(result, records);
                            } else {
                                setFailure(result, new DnsException(code));
                            }
                            ctx.close();
                        }

                        private boolean isRequestedType(DnsRecordType dnsRecordType, DnsRecordType[] types) {
                            for (DnsRecordType t : types) {
                                if (t.equals(dnsRecordType)) {
                                    return true;
                                }
                            }
                            return false;
                        }

                        @Override
                        public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause)
                                throws Exception {
                            setFailure(result, cause);
                            ctx.close();
                        }
                    });
                }
            });
        }
    });
}

---

From source file:io.vertx.core.dns.impl.fix.DnsNameResolverContext.java

License:Apache License

private void onResponseAorAAAA(DnsRecordType qType, DnsQuestion question,
        AddressedEnvelope<DnsResponse, InetSocketAddress> envelope) {

    // We often get a bunch of CNAMES as well when we asked for A/AAAA.
    final DnsResponse response = envelope.content();
    final Map<String, String> cnames = buildAliasMap(response);
    final int answerCount = response.count(DnsSection.ANSWER);

    boolean found = false;
    for (int i = 0; i < answerCount; i++) {
        final DnsRecord r = response.recordAt(DnsSection.ANSWER, i);
        final DnsRecordType type = r.type();
        if (type != DnsRecordType.A && type != DnsRecordType.AAAA) {
            continue;
        }//  w w  w  .j av  a 2  s. c o m

        final String qName = question.name().toLowerCase(Locale.US);
        final String rName = r.name().toLowerCase(Locale.US);

        // Make sure the record is for the questioned domain.
        if (!rName.equals(qName)) {
            // Even if the record's name is not exactly same, it might be an alias defined in the CNAME records.
            String resolved = qName;
            do {
                resolved = cnames.get(resolved);
                if (rName.equals(resolved)) {
                    break;
                }
            } while (resolved != null);

            if (resolved == null) {
                continue;
            }
        }

        if (!(r instanceof DnsRawRecord)) {
            continue;
        }

        final ByteBuf content = ((ByteBufHolder) r).content();
        final int contentLen = content.readableBytes();
        if (contentLen != INADDRSZ4 && contentLen != INADDRSZ6) {
            continue;
        }

        final byte[] addrBytes = new byte[contentLen];
        content.getBytes(content.readerIndex(), addrBytes);

        final InetAddress resolved;
        try {
            resolved = InetAddress.getByAddress(hostname, addrBytes);
        } catch (UnknownHostException e) {
            // Should never reach here.
            throw new Error(e);
        }

        if (resolvedEntries == null) {
            resolvedEntries = new ArrayList<DnsCacheEntry>(8);
        }

        final DnsCacheEntry e = new DnsCacheEntry(hostname, resolved);
        resolveCache.cache(hostname, resolved, r.timeToLive(), parent.ch.eventLoop());
        resolvedEntries.add(e);
        found = true;

        // Note that we do not break from the loop here, so we decode/cache all A/AAAA records.
    }

    if (found) {
        return;
    }

    if (traceEnabled) {
        addTrace(envelope.sender(), "no matching " + qType + " record found");
    }

    // We aked for A/AAAA but we got only CNAME.
    if (!cnames.isEmpty()) {
        onResponseCNAME(question, envelope, cnames, false);
    }
}

---

From source file:io.vertx.core.dns.impl.fix.DnsNameResolverContext.java

License:Apache License

private static Map<String, String> buildAliasMap(DnsResponse response) {
    final int answerCount = response.count(DnsSection.ANSWER);
    Map<String, String> cnames = null;
    for (int i = 0; i < answerCount; i++) {
        final DnsRecord r = response.recordAt(DnsSection.ANSWER, i);
        final DnsRecordType type = r.type();
        if (type != DnsRecordType.CNAME) {
            continue;
        }//w ww  . ja  v a2 s  .  co m

        if (!(r instanceof DnsRawRecord)) {
            continue;
        }

        final ByteBuf recordContent = ((ByteBufHolder) r).content();
        final String domainName = decodeDomainName(recordContent);
        if (domainName == null) {
            continue;
        }

        if (cnames == null) {
            cnames = new HashMap<String, String>();
        }

        cnames.put(r.name().toLowerCase(Locale.US), domainName.toLowerCase(Locale.US));
    }

    return cnames != null ? cnames : Collections.<String, String>emptyMap();
}

---