Commit Graph

17 Commits

Author SHA1 Message Date
Trustin Lee
ad0b7ca56d Add a test case for DNS resolver cache for negative loopups
Related issue: #4065
2015-08-18 18:44:51 +09:00
Trustin Lee
1856ab3a35 Make DnsNameResolverTest.testQueryMx() more robust
Motivation:

DNS servers seem to reply with ServFail(2) response code when it is
busy.

Modifications:

- Retry when response code is ServFail instead of failing the test
- Try all DNS servers instead of retrying twice only

Result:

testQueryMx() is less likely to fail due to public DNS server problems
2015-08-18 18:26:11 +09:00
Trustin Lee
fdfe3149ba Provide more control over DnsNameResolver.query() / Add NameResolver.resolveAll()
Related issues:
- #3971
- #3973
- #3976
- #4035

Motivation:

1. Previously, DnsNameResolver.query() retried the request query by its
own. It prevents a user from deciding when to retry or stop. It is also
impossible to get the response object whose code is not NOERROR.

2. NameResolver does not have an operation that resolves a host name
into multiple addresses, like InetAddress.getAllByName()

Modifications:

- Changes related with DnsNameResolver.query()
  - Make query() not retry
    - Move the retry logic to DnsNameResolver.resolve() instead.
  - Make query() fail the promise only when I/O error occurred or it
    failed to get a response
  - Add DnsNameResolverException and use it when query() fails so that
    the resolver can give more information about the failure
  - query() does not cache anymore.

- Changes related with NameResolver.resolveAll()
  - Add NameResolver.resolveAll()
  - Add SimpleNameResolver.doResolveAll()

- Changes related with DnsNameResolver.resolve() and resolveAll()
  - Make DnsNameResolveContext abstract so that DnsNameResolver can
    decide to get single or multiple addresses from it
  - Re-implement cache so that the cache works for resolve() and
    resolveAll()
  - Add 'traceEnabled' property to enable/disable trace information

- Miscellaneous changes
  - Use ObjectUtil.checkNotNull() wherever possible
  - Add InternetProtocolFamily.addressType() to remove repetitive
    switch-case blocks in DnsNameResolver(Context)
  - Do not raise an exception when decoding a truncated DNS response

Result:

- Full control over query()
- A user can now retrieve all addresses via (Dns)NameResolver.resolveAll()
- DNS cache works only for resolve() and resolveAll() now.
2015-08-18 17:40:13 +09:00
Norman Maurer
d1344345bb DnsResolver.resolve(...) fails when ipaddress is used.
Motivation:

DnsResolver.resolve(...) fails when an InetSocketAddress is used that was constructed of an ipaddress string.

Modifications:

Don't try to lookup when the InetSocketAddress was constructed via an ipaddress.

Result:

DnsResolver.resolve(...) works in all cases.
2015-07-18 17:14:05 +02:00
Trustin Lee
311532feb0 Fix IllegalReferenceCountException in DnsNameResolver
Related: #3797

Motivation:

There is a race condition where DnsNameResolver.query() can attempt to
increase the reference count of the DNS response which was released
already by other thread.

Modifications:

- Make DnsCacheEntry a top-level class for clear access control
- Use 'synchronized' to avoid the race condition
  - Add DnsCacheEntry.retainedResponse() to make sure that the response
    is never released while it is retained
  - Make retainedResponse() return null when the response has been
    released already, so that DnsNameResolver.query() knows that the
    cached entry has been released

Result:

The forementioned race condition has been fixed.
2015-06-03 19:17:56 +09:00
Norman Maurer
f23b7b4efd [maven-release-plugin] prepare for next development iteration 2015-05-07 14:21:08 -04:00
Norman Maurer
871ce43b1f [maven-release-plugin] prepare release netty-4.1.0.Beta5 2015-05-07 14:20:38 -04:00
Trustin Lee
63a02fc04e Revamp DNS codec
Motivation:

There are various known issues in netty-codec-dns:

- Message types are not interfaces, which can make it difficult for a
  user to implement his/her own message implementation.
- Some class names and field names do not match with the terms in the
  RFC.
- The support for decoding a DNS record was limited. A user had to
  encode and decode by him/herself.
- The separation of DnsHeader from DnsMessage was unnecessary, although
  it is fine conceptually.
- Buffer leak caused by DnsMessage was difficult to analyze, because the
  leak detector tracks down the underlying ByteBuf rather than the
  DnsMessage itself.
- DnsMessage assumes DNS-over-UDP.
- To send an EDNS message, a user have to create a new DNS record class
  instance unnecessarily.

Modifications:

- Make all message types interfaces and add default implementations
- Rename some classes, properties, and constants to match the RFCs
  - DnsResource -> DnsRecord
  - DnsType -> DnsRecordType
  - and many more
- Remove DnsClass and use an integer to support EDNS better
- Add DnsRecordEncoder/DnsRecordDecoder and their default
  implementations
  - DnsRecord does not require RDATA to be ByteBuf anymore.
  - Add DnsRawRecord as the catch-all record type
- Merge DnsHeader into DnsMessage
- Make ResourceLeakDetector track AbstractDnsMessage
- Remove DnsMessage.sender/recipient properties
  - Wrap DnsMessage with AddressedEnvelope
  - Add DatagramDnsQuest and DatagramDnsResponse for ease of use
  - Rename DnsQueryEncoder to DatagramDnsQueryEncoder
  - Rename DnsResponseDecoder to DatagramDnsResponseDecoder
- Miscellaneous changes
  - Add StringUtil.TAB

Result:

- Cleaner APi
- Can support DNS-over-TCP more easily in the future
- Reduced memory footprint in the default DnsQuery/Response
  implementations
- Better leak tracking for DnsMessages
- Possibility to introduce new DnsRecord types in the future and provide
  full record encoder/decoder implementation.
- No unnecessary instantiation for an EDNS pseudo resource record
2015-05-01 11:33:16 +09:00
Norman Maurer
fce0989844 [maven-release-plugin] prepare for next development iteration 2015-03-03 02:06:47 -05:00
Norman Maurer
ca3b1bc4b7 [maven-release-plugin] prepare release netty-4.1.0.Beta4 2015-03-03 02:05:52 -05:00
Trustin Lee
79bb200f59 Remove thepiratebay.se from the test domain list
.. due to its instability
2014-12-22 22:35:17 +09:00
Trustin Lee
23db94f5a1 Fix Java 6 compatibility issue in DnsNameResolver
Related: #3173

Motivation:

DnsNameResolver was using InetSocketAddress.getHostString() which is
only available since Java 7.

Modifications:

Use InetSocketAddress.getHostName() in lieu of getHostString() when the
current Java version is less than 7.

Result:

DnsNameResolver runs fine on Java 6.
2014-12-06 22:31:44 +09:00
Jay
2769ad428a Check the bindFuture before writing a DNS query
Related: #3149

Motivation:

DnsQueryContext, using the DatagramChannel bound in DnsNameResolver,
blindly writes to the channel without checking the bind future for
success.

Modifications:

Check the bindFuture before writing a DNS query to a DatagramChannel

Result:

Bug fixed
2014-12-01 19:46:18 +09:00
Trustin Lee
c0079840be Improve DnsNameResolverTest.testResolveA()
Motivation:

DnsNameResolver.testResolveA() tests if the cache works as well as the usual DNS protocol test.  To ensure the result from the cache is identical to the result without cache, it compares the two Maps which contain the result of cached/uncached resolution.  The comparison of two Maps yields an expected behavior, but the output of the comparison on failure is often unreadable due to its long length.

Modifications:

Compare entry-by-entry for more comprehensible test failure output

Result:

When failure occurs, it's easier to see which domain was the cause of the problem.
2014-10-25 17:29:06 +09:00
Trustin Lee
e1787e6876 Fix another resource leak in DnsNameResolver
- Fix a bug in cache expiration task; wrong object was being released
- Added more sanity checks when caching an entry
2014-10-17 11:40:06 +09:00
Trustin Lee
c811d50d61 Fix resource leak in DnsNameResolver 2014-10-16 17:57:32 +09:00
Trustin Lee
e848066cab Name resolver API and DNS-based name resolver
Motivation:

So far, we relied on the domain name resolution mechanism provided by
JDK.  It served its purpose very well, but had the following
shortcomings:

- Domain name resolution is performed in a blocking manner.
  This becomes a problem when a user has to connect to thousands of
  different hosts. e.g. web crawlers
- It is impossible to employ an alternative cache/retry policy.
  e.g. lower/upper bound in TTL, round-robin
- It is impossible to employ an alternative name resolution mechanism.
  e.g. Zookeeper-based name resolver

Modification:

- Add the resolver API in the new module: netty-resolver
- Implement the DNS-based resolver: netty-resolver-dns
  .. which uses netty-codec-dns
- Make ChannelFactory reusable because it's now used by
  io.netty.bootstrap, io.netty.resolver.dns, and potentially by other
  modules in the future
  - Move ChannelFactory from io.netty.bootstrap to io.netty.channel
  - Deprecate the old ChannelFactory
  - Add ReflectiveChannelFactory

Result:

It is trivial to resolve a large number of domain names asynchronously.
2014-10-16 17:05:20 +09:00