Motivation:
1. The use of InternetProtocolFamily is not consistent:
the DnsNameResolverContext and DnsNameResolver contains switches
instead of appropriate methods usage.
2. The InternetProtocolFamily class contains redundant switches in the
constructor.
Modifications:
1. Replacing switches to the use of an appropriate methods.
2. Simplifying the InternetProtocolFamily constructor.
Result:
Code is cleaner and simpler.
Motivation:
RFC7871 defines an extension which allows to request responses for a given subset.
Modifications:
- Add DnsOptPseudoRrRecord which can act as base class for extensions based on EDNS(0) as defined in RFC6891
- Add DnsOptEcsRecord to support the Client Subnet in DNS Queries extension
- Add tests
Result:
Client Subnet in DNS Queries extension is now supported.
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.
