bbb6e126b1
Motiviation: We incorrectly did ignore NS servers during redirect which had no ADDITIONAL record. This could at worse have the affect that we failed the query completely as none of the NS servers had a ADDITIONAL record. Beside this using a DnsCache to cache authoritative nameservers does not work in practise as we we need different features and semantics when cache these servers (for example we also want to cache unresolved nameservers and resolve these on the fly when needed). Modifications: - Correctly take NS records into account that have no matching ADDITIONAL record - Correctly handle multiple ADDITIONAL records for the same NS record - Introduce AuthoritativeDnsServerCache as a replacement of the DnsCache when caching authoritative nameservers + adding default implementation - Add an adapter layer to reduce API breakage as much as possible - Replace DnsNameResolver.uncachedRedirectDnsServerStream(...) with newRedirectDnsServerStream(...) - Add unit tests Result: Our DnsResolver now correctly handle redirects in all cases.
64 lines
2.2 KiB
Java
64 lines
2.2 KiB
Java
/*
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* Copyright 2018 The Netty Project
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*
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* The Netty Project licenses this file to you under the Apache License,
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* version 2.0 (the "License"); you may not use this file except in compliance
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* with the License. You may obtain a copy of the License at:
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*/
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package io.netty.resolver.dns;
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import io.netty.channel.EventLoop;
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import io.netty.util.internal.UnstableApi;
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import java.net.InetSocketAddress;
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/**
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* Cache which stores the nameservers that should be used to resolve a specific hostname.
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*/
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@UnstableApi
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public interface AuthoritativeDnsServerCache {
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/**
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* Returns the cached nameservers that should be used to resolve the given hostname. The returned
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* {@link DnsServerAddressStream} may contain unresolved {@link InetSocketAddress}es that will be resolved
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* when needed while resolving other domain names.
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*
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* @param hostname the hostname
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* @return the cached entries or an {@code null} if none.
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*/
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DnsServerAddressStream get(String hostname);
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/**
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* Caches a nameserver that should be used to resolve the given hostname.
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*
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* @param hostname the hostname
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* @param address the nameserver address (which may be unresolved).
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* @param originalTtl the TTL as returned by the DNS server
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* @param loop the {@link EventLoop} used to register the TTL timeout
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*/
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void cache(String hostname, InetSocketAddress address, long originalTtl, EventLoop loop);
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/**
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* Clears all cached nameservers.
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*
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* @see #clear(String)
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*/
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void clear();
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/**
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* Clears the cached nameservers for the specified hostname.
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*
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* @return {@code true} if and only if there was an entry for the specified host name in the cache and
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* it has been removed by this method
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*/
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boolean clear(String hostname);
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}
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