Implement correct handling of recursive DNS
Motivation: DnsNameResolver does not handle recursive DNS and so fails if you query a DNS server (for example a ROOT dns server) which provides the correct redirect for a domain. Modification: Add support for redirects (a.k.a. handling of AUTHORITY section'). Result: Its now possible to use a DNS server that redirects.
This commit is contained in:
Norman Maurer
parent
8a5e42ad2e
commit
661ff2538e
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@ -132,6 +132,7 @@ public class DnsNameResolver extends InetNameResolver {
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* Cache for {@link #doResolve(String, Promise)} and {@link #doResolveAll(String, Promise)}.
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*/
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private final DnsCache resolveCache;
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private final DnsCache authoritativeDnsServerCache;
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private final FastThreadLocal<DnsServerAddressStream> nameServerAddrStream =
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new FastThreadLocal<DnsServerAddressStream>() {
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@ -151,8 +152,8 @@ public class DnsNameResolver extends InetNameResolver {
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private final HostsFileEntriesResolver hostsFileEntriesResolver;
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private final String[] searchDomains;
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private final int ndots;
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private final boolean cnameFollowARecords;
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private final boolean cnameFollowAAAARecords;
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private final boolean supportsAAAARecords;
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private final boolean supportsARecords;
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private final InternetProtocolFamily preferredAddressType;
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private final DnsRecordType[] resolveRecordTypes;
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private final boolean decodeIdn;
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@ -176,9 +177,9 @@ public class DnsNameResolver extends InetNameResolver {
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* @param hostsFileEntriesResolver the {@link HostsFileEntriesResolver} used to check for local aliases
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* @param searchDomains the list of search domain
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* @param ndots the ndots value
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* @deprecated use {@link #DnsNameResolver(EventLoop, ChannelFactory, DnsServerAddresses, DnsCache, long,
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* InternetProtocolFamily[], boolean, int, boolean, int,
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* boolean, HostsFileEntriesResolver, String[], int, boolean)}
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* @deprecated use {@link DnsNameResolver#DnsNameResolver(EventLoop, ChannelFactory, DnsServerAddresses, DnsCache,
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* DnsCache, long, InternetProtocolFamily[], boolean, int, boolean, int, boolean,
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* HostsFileEntriesResolver, String[], int, boolean)}
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*/
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@Deprecated
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public DnsNameResolver(
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@ -196,11 +197,10 @@ public class DnsNameResolver extends InetNameResolver {
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HostsFileEntriesResolver hostsFileEntriesResolver,
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String[] searchDomains,
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int ndots) {
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this(eventLoop, channelFactory, nameServerAddresses, resolveCache, queryTimeoutMillis, resolvedAddressTypes,
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recursionDesired, maxQueriesPerResolve, traceEnabled, maxPayloadSize, optResourceEnabled,
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hostsFileEntriesResolver, searchDomains, ndots, true);
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this(eventLoop, channelFactory, nameServerAddresses, resolveCache, NoopDnsCache.INSTANCE, queryTimeoutMillis,
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resolvedAddressTypes, recursionDesired, maxQueriesPerResolve, traceEnabled, maxPayloadSize,
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optResourceEnabled, hostsFileEntriesResolver, searchDomains, ndots, true);
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}
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/**
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* Creates a new DNS-based name resolver that communicates with the specified list of DNS servers.
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*
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@ -210,6 +210,7 @@ public class DnsNameResolver extends InetNameResolver {
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* this to determine which DNS server should be contacted for the next retry in case
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* of failure.
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* @param resolveCache the DNS resolved entries cache
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* @param authoritativeDnsServerCache the cache used to find the authoritative DNS server for a domain
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* @param queryTimeoutMillis timeout of each DNS query in millis
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* @param resolvedAddressTypes list of the protocol families
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* @param recursionDesired if recursion desired flag must be set
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@ -228,6 +229,7 @@ public class DnsNameResolver extends InetNameResolver {
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ChannelFactory<? extends DatagramChannel> channelFactory,
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DnsServerAddresses nameServerAddresses,
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final DnsCache resolveCache,
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DnsCache authoritativeDnsServerCache,
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long queryTimeoutMillis,
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InternetProtocolFamily[] resolvedAddressTypes,
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boolean recursionDesired,
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@ -239,7 +241,6 @@ public class DnsNameResolver extends InetNameResolver {
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String[] searchDomains,
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int ndots,
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boolean decodeIdn) {
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super(eventLoop);
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checkNotNull(channelFactory, "channelFactory");
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this.nameServerAddresses = checkNotNull(nameServerAddresses, "nameServerAddresses");
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@ -252,22 +253,23 @@ public class DnsNameResolver extends InetNameResolver {
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this.optResourceEnabled = optResourceEnabled;
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this.hostsFileEntriesResolver = checkNotNull(hostsFileEntriesResolver, "hostsFileEntriesResolver");
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this.resolveCache = checkNotNull(resolveCache, "resolveCache");
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this.authoritativeDnsServerCache = checkNotNull(authoritativeDnsServerCache, "authoritativeDnsServerCache");
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this.searchDomains = checkNotNull(searchDomains, "searchDomains").clone();
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this.ndots = checkPositiveOrZero(ndots, "ndots");
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this.decodeIdn = decodeIdn;
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boolean cnameFollowARecords = false;
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boolean cnameFollowAAAARecords = false;
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boolean supportsARecords = false;
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boolean supportsAAAARecords = false;
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// Use LinkedHashSet to maintain correct ordering.
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Set<DnsRecordType> recordTypes = new LinkedHashSet<DnsRecordType>(resolvedAddressTypes.length);
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for (InternetProtocolFamily family: resolvedAddressTypes) {
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switch (family) {
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case IPv4:
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cnameFollowARecords = true;
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supportsARecords = true;
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recordTypes.add(DnsRecordType.A);
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break;
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case IPv6:
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cnameFollowAAAARecords = true;
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supportsAAAARecords = true;
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recordTypes.add(DnsRecordType.AAAA);
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break;
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default:
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@ -276,9 +278,9 @@ public class DnsNameResolver extends InetNameResolver {
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}
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// One of both must be always true.
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assert cnameFollowARecords || cnameFollowAAAARecords;
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this.cnameFollowAAAARecords = cnameFollowAAAARecords;
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this.cnameFollowARecords = cnameFollowARecords;
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assert supportsARecords || supportsAAAARecords;
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this.supportsAAAARecords = supportsAAAARecords;
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this.supportsARecords = supportsARecords;
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resolveRecordTypes = recordTypes.toArray(new DnsRecordType[recordTypes.size()]);
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preferredAddressType = resolvedAddressTypes[0];
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@ -306,6 +308,11 @@ public class DnsNameResolver extends InetNameResolver {
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});
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}
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// Only here to override in unit tests.
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int dnsRedirectPort(@SuppressWarnings("unused") InetAddress server) {
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return DnsServerAddresses.DNS_PORT;
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}
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/**
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* Returns the resolution cache.
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*/
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@ -313,6 +320,13 @@ public class DnsNameResolver extends InetNameResolver {
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return resolveCache;
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}
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/**
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* Returns the cache used for authoritative DNS servers for a domain.
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*/
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public DnsCache authoritativeDnsServerCache() {
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return authoritativeDnsServerCache;
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}
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/**
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* Returns the timeout of each DNS query performed by this resolver (in milliseconds).
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* The default value is 5 seconds.
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@ -342,12 +356,12 @@ public class DnsNameResolver extends InetNameResolver {
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return ndots;
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}
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final boolean isCnameFollowAAAARecords() {
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return cnameFollowAAAARecords;
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final boolean supportsAAAARecords() {
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return supportsAAAARecords;
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}
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final boolean isCnameFollowARecords() {
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return cnameFollowARecords;
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final boolean supportsARecords() {
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return supportsARecords;
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}
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final InternetProtocolFamily preferredAddressType() {
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@ -40,6 +40,7 @@ public final class DnsNameResolverBuilder {
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private ChannelFactory<? extends DatagramChannel> channelFactory;
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private DnsServerAddresses nameServerAddresses = DnsServerAddresses.defaultAddresses();
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private DnsCache resolveCache;
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private DnsCache authoritativeDnsServerCache;
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private Integer minTtl;
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private Integer maxTtl;
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private Integer negativeTtl;
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@ -109,6 +110,17 @@ public final class DnsNameResolverBuilder {
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return this;
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}
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/**
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* Sets the cache for authoritive NS servers
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*
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* @param authoritativeDnsServerCache the authoritive NS servers cache
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* @return {@code this}
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*/
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public DnsNameResolverBuilder authoritativeDnsServerCache(DnsCache authoritativeDnsServerCache) {
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this.authoritativeDnsServerCache = authoritativeDnsServerCache;
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return this;
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}
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/**
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* Sets the minimum and maximum TTL of the cached DNS resource records (in seconds). If the TTL of the DNS
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* resource record returned by the DNS server is less than the minimum TTL or greater than the maximum TTL,
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@ -331,6 +343,10 @@ public final class DnsNameResolverBuilder {
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return this;
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}
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private DnsCache newCache() {
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return new DefaultDnsCache(intValue(minTtl, 0), intValue(maxTtl, Integer.MAX_VALUE), intValue(negativeTtl, 0));
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}
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/**
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* Set if domain / host names should be decoded to unicode when received.
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* See <a href="https://tools.ietf.org/html/rfc3492">rfc3492</a>.
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@ -349,19 +365,23 @@ public final class DnsNameResolverBuilder {
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* @return a {@link DnsNameResolver}
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*/
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public DnsNameResolver build() {
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if (resolveCache != null && (minTtl != null || maxTtl != null || negativeTtl != null)) {
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throw new IllegalStateException("resolveCache and TTLs are mutually exclusive");
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}
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DnsCache cache = resolveCache != null ? resolveCache :
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new DefaultDnsCache(intValue(minTtl, 0), intValue(maxTtl, Integer.MAX_VALUE), intValue(negativeTtl, 0));
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if (authoritativeDnsServerCache != null && (minTtl != null || maxTtl != null || negativeTtl != null)) {
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throw new IllegalStateException("authoritativeDnsServerCache and TTLs are mutually exclusive");
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}
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DnsCache resolveCache = this.resolveCache != null ? this.resolveCache : newCache();
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DnsCache authoritativeDnsServerCache = this.authoritativeDnsServerCache != null ?
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this.authoritativeDnsServerCache : newCache();
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return new DnsNameResolver(
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eventLoop,
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channelFactory,
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nameServerAddresses,
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cache,
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resolveCache,
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authoritativeDnsServerCache,
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queryTimeoutMillis,
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resolvedAddressTypes,
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recursionDesired,
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@ -145,15 +145,103 @@ abstract class DnsNameResolverContext<T> {
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}
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private void internalResolve(Promise<T> promise) {
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InetSocketAddress nameServerAddrToTry = nameServerAddrs.next();
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DnsServerAddressStream nameServerAddressStream = getNameServers(hostname);
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for (DnsRecordType type: parent.resolveRecordTypes()) {
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if (!query(hostname, type, nameServerAddrToTry, promise)) {
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if (!query(hostname, type, nameServerAddressStream, promise)) {
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return;
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}
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}
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}
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private void query(InetSocketAddress nameServerAddr, final DnsQuestion question, final Promise<T> promise) {
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/**
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* Add an authoritative nameserver to the cache if its not a root server.
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*/
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private void addNameServerToCache(
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AuthoritativeNameServer name, InetAddress resolved, long ttl) {
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if (!name.isRootServer()) {
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// Cache NS record if not for a root server as we should never cache for root servers.
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parent.authoritativeDnsServerCache().cache(name.domainName(),
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additionals, resolved, ttl, parent.ch.eventLoop());
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}
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}
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/**
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* Returns the {@link DnsServerAddressStream} that was cached for the given hostname or {@code null} if non
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* could be found.
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*/
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private DnsServerAddressStream getNameServersFromCache(String hostname) {
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int len = hostname.length();
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if (len == 0) {
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// We never cache for root servers.
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return null;
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}
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// We always store in the cache with a trailing '.'.
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if (hostname.charAt(len - 1) != '.') {
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hostname += ".";
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}
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int idx = hostname.indexOf('.');
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if (idx == hostname.length() - 1) {
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// We are not interested in handling '.' as we should never serve the root servers from cache.
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return null;
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}
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// We start from the closed match and then move down.
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for (;;) {
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// Skip '.' as well.
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hostname = hostname.substring(idx + 1);
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int idx2 = hostname.indexOf('.');
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if (idx2 <= 0 || idx2 == hostname.length() - 1) {
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// We are not interested in handling '.TLD.' as we should never serve the root servers from cache.
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return null;
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}
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idx = idx2;
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List<DnsCacheEntry> entries = parent.authoritativeDnsServerCache().get(hostname, additionals);
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if (entries != null && !entries.isEmpty()) {
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// Found a match in the cache... Also shuffle them so we not always use the same order for lookup.
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return DnsServerAddresses.shuffled(new DnsCacheIterable(entries)).stream();
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}
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}
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}
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private final class DnsCacheIterable implements Iterable<InetSocketAddress> {
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private final List<DnsCacheEntry> entries;
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DnsCacheIterable(List<DnsCacheEntry> entries) {
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this.entries = entries;
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}
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@Override
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public Iterator<InetSocketAddress> iterator() {
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return new Iterator<InetSocketAddress>() {
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Iterator<DnsCacheEntry> entryIterator = entries.iterator();
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@Override
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public boolean hasNext() {
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return entryIterator.hasNext();
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}
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@Override
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public InetSocketAddress next() {
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InetAddress address = entryIterator.next().address();
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return new InetSocketAddress(address, parent.dnsRedirectPort(address));
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}
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@Override
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public void remove() {
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entryIterator.remove();
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}
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};
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}
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}
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private void query(final DnsServerAddressStream nameServerAddrStream, final DnsQuestion question,
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final Promise<T> promise) {
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if (allowedQueries == 0 || promise.isCancelled()) {
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tryToFinishResolve(promise);
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return;
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@ -162,7 +250,7 @@ abstract class DnsNameResolverContext<T> {
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allowedQueries --;
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final Future<AddressedEnvelope<DnsResponse, InetSocketAddress>> f = parent.query0(
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nameServerAddr, question, additionals,
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nameServerAddrStream.next(), question, additionals,
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parent.ch.eventLoop().<AddressedEnvelope<? extends DnsResponse, InetSocketAddress>>newPromise());
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queriesInProgress.add(f);
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@ -177,13 +265,13 @@ abstract class DnsNameResolverContext<T> {
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try {
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if (future.isSuccess()) {
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onResponse(question, future.getNow(), promise);
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onResponse(nameServerAddrStream, question, future.getNow(), promise);
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} else {
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// Server did not respond or I/O error occurred; try again.
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if (traceEnabled) {
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addTrace(future.cause());
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}
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query(nameServerAddrs.next(), question, promise);
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query(nameServerAddrStream, question, promise);
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}
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} finally {
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tryToFinishResolve(promise);
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@ -192,13 +280,18 @@ abstract class DnsNameResolverContext<T> {
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});
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}
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void onResponse(final DnsQuestion question, AddressedEnvelope<DnsResponse, InetSocketAddress> envelope,
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Promise<T> promise) {
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void onResponse(final DnsServerAddressStream nameServerAddrStream, final DnsQuestion question,
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AddressedEnvelope<DnsResponse, InetSocketAddress> envelope, Promise<T> promise) {
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try {
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final DnsResponse res = envelope.content();
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final DnsResponseCode code = res.code();
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if (code == DnsResponseCode.NOERROR) {
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if (handleRedirect(question, envelope, promise)) {
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// Was a redirect so return here as everything else is handled in handleRedirect(...)
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return;
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}
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final DnsRecordType type = question.type();
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if (type == DnsRecordType.A || type == DnsRecordType.AAAA) {
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onResponseAorAAAA(type, question, envelope, promise);
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} else if (type == DnsRecordType.CNAME) {
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@ -215,13 +308,86 @@ abstract class DnsNameResolverContext<T> {
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// Retry with the next server if the server did not tell us that the domain does not exist.
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if (code != DnsResponseCode.NXDOMAIN) {
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query(nameServerAddrs.next(), question, promise);
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query(nameServerAddrStream, question, promise);
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}
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} finally {
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ReferenceCountUtil.safeRelease(envelope);
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}
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}
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/**
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* Handle redirects if needed and returns {@code true} if there was a redirect handled. If {@code true} is returned
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* this method took ownership of the {@code promise} otherwise {@code false} is returned.
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*/
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private boolean handleRedirect(
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DnsQuestion question, AddressedEnvelope<DnsResponse, InetSocketAddress> envelope, Promise<T> promise) {
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final DnsResponse res = envelope.content();
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// Check if we have answers, if not this may be an non authority NS and so redirects must be handled.
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if (res.count(DnsSection.ANSWER) == 0) {
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AuthoritativeNameServerList serverNames = extractAuthoritativeNameServers(question.name(), res);
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if (serverNames != null) {
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List<InetSocketAddress> nameServers = new ArrayList<InetSocketAddress>(serverNames.size());
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int additionalCount = res.count(DnsSection.ADDITIONAL);
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for (int i = 0; i < additionalCount; i++) {
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final DnsRecord r = res.recordAt(DnsSection.ADDITIONAL, i);
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if ((r.type() == DnsRecordType.A && !parent.supportsARecords()) ||
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r.type() == DnsRecordType.AAAA && !parent.supportsAAAARecords()) {
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continue;
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}
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final String recordName = r.name();
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AuthoritativeNameServer authoritativeNameServer =
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serverNames.remove(recordName);
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if (authoritativeNameServer == null) {
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// Not a server we are interested in.
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continue;
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}
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InetAddress resolved = parseAddress(r, recordName);
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if (resolved == null) {
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// Could not parse it, move to the next.
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continue;
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}
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nameServers.add(new InetSocketAddress(resolved, parent.dnsRedirectPort(resolved)));
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addNameServerToCache(authoritativeNameServer, resolved, r.timeToLive());
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}
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if (nameServers.isEmpty()) {
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promise.tryFailure(
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new UnknownHostException("Unable to find correct name server for " + hostname));
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} else {
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// Shuffle as we want to re-distribute the load across name servers.
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query(DnsServerAddresses.shuffled(nameServers).stream(), question, promise);
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}
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||||
return true;
|
||||
}
|
||||
}
|
||||
return false;
|
||||
}
|
||||
|
||||
/**
|
||||
* Returns the {@code {@link AuthoritativeNameServerList} which were included in {@link DnsSection#AUTHORITY}
|
||||
* or {@code null} if non are found.
|
||||
*/
|
||||
private static AuthoritativeNameServerList extractAuthoritativeNameServers(String questionName, DnsResponse res) {
|
||||
int authorityCount = res.count(DnsSection.AUTHORITY);
|
||||
if (authorityCount == 0) {
|
||||
return null;
|
||||
}
|
||||
|
||||
AuthoritativeNameServerList serverNames = new AuthoritativeNameServerList(questionName);
|
||||
for (int i = 0; i < authorityCount; i++) {
|
||||
serverNames.add(res.recordAt(DnsSection.AUTHORITY, i));
|
||||
}
|
||||
return serverNames;
|
||||
}
|
||||
|
||||
private void onResponseAorAAAA(
|
||||
DnsRecordType qType, DnsQuestion question, AddressedEnvelope<DnsResponse, InetSocketAddress> envelope,
|
||||
Promise<T> promise) {
|
||||
|
|
@ -239,16 +405,16 @@ abstract class DnsNameResolverContext<T> {
|
|||
continue;
|
||||
}
|
||||
|
||||
final String qName = question.name().toLowerCase(Locale.US);
|
||||
final String rName = r.name().toLowerCase(Locale.US);
|
||||
final String questionName = question.name().toLowerCase(Locale.US);
|
||||
final String recordName = r.name().toLowerCase(Locale.US);
|
||||
|
||||
// Make sure the record is for the questioned domain.
|
||||
if (!rName.equals(qName)) {
|
||||
if (!recordName.equals(questionName)) {
|
||||
// Even if the record's name is not exactly same, it might be an alias defined in the CNAME records.
|
||||
String resolved = qName;
|
||||
String resolved = questionName;
|
||||
do {
|
||||
resolved = cnames.get(resolved);
|
||||
if (rName.equals(resolved)) {
|
||||
if (recordName.equals(resolved)) {
|
||||
break;
|
||||
}
|
||||
} while (resolved != null);
|
||||
|
|
@ -258,28 +424,11 @@ abstract class DnsNameResolverContext<T> {
|
|||
}
|
||||
}
|
||||
|
||||
if (!(r instanceof DnsRawRecord)) {
|
||||
InetAddress resolved = parseAddress(r, hostname);
|
||||
if (resolved == null) {
|
||||
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(
|
||||
parent.isDecodeIdn() ? IDN.toUnicode(hostname) : hostname, addrBytes);
|
||||
} catch (UnknownHostException e) {
|
||||
// Should never reach here.
|
||||
throw new Error(e);
|
||||
}
|
||||
|
||||
if (resolvedEntries == null) {
|
||||
resolvedEntries = new ArrayList<DnsCacheEntry>(8);
|
||||
}
|
||||
|
|
@ -306,6 +455,28 @@ abstract class DnsNameResolverContext<T> {
|
|||
}
|
||||
}
|
||||
|
||||
private InetAddress parseAddress(DnsRecord r, String name) {
|
||||
if (!(r instanceof DnsRawRecord)) {
|
||||
return null;
|
||||
}
|
||||
final ByteBuf content = ((ByteBufHolder) r).content();
|
||||
final int contentLen = content.readableBytes();
|
||||
if (contentLen != INADDRSZ4 && contentLen != INADDRSZ6) {
|
||||
return null;
|
||||
}
|
||||
|
||||
final byte[] addrBytes = new byte[contentLen];
|
||||
content.getBytes(content.readerIndex(), addrBytes);
|
||||
|
||||
try {
|
||||
return InetAddress.getByAddress(
|
||||
parent.isDecodeIdn() ? IDN.toUnicode(name) : name, addrBytes);
|
||||
} catch (UnknownHostException e) {
|
||||
// Should never reach here.
|
||||
throw new Error(e);
|
||||
}
|
||||
}
|
||||
|
||||
private void onResponseCNAME(DnsQuestion question, AddressedEnvelope<DnsResponse, InetSocketAddress> envelope,
|
||||
Promise<T> promise) {
|
||||
onResponseCNAME(question, envelope, buildAliasMap(envelope.content()), true, promise);
|
||||
|
|
@ -386,7 +557,8 @@ abstract class DnsNameResolverContext<T> {
|
|||
if (!triedCNAME) {
|
||||
// As the last resort, try to query CNAME, just in case the name server has it.
|
||||
triedCNAME = true;
|
||||
query(hostname, DnsRecordType.CNAME, nameServerAddrs.next(), promise);
|
||||
|
||||
query(hostname, DnsRecordType.CNAME, getNameServers(hostname), promise);
|
||||
return;
|
||||
}
|
||||
}
|
||||
|
|
@ -496,6 +668,11 @@ abstract class DnsNameResolverContext<T> {
|
|||
}
|
||||
}
|
||||
|
||||
private DnsServerAddressStream getNameServers(String hostame) {
|
||||
DnsServerAddressStream stream = getNameServersFromCache(hostame);
|
||||
return stream == null ? nameServerAddrs : stream;
|
||||
}
|
||||
|
||||
private void followCname(InetSocketAddress nameServerAddr, String name, String cname, Promise<T> promise) {
|
||||
|
||||
if (traceEnabled) {
|
||||
|
|
@ -512,16 +689,18 @@ abstract class DnsNameResolverContext<T> {
|
|||
trace.append(cname);
|
||||
}
|
||||
|
||||
final InetSocketAddress nextAddr = nameServerAddrs.next();
|
||||
if (parent.isCnameFollowARecords() && !query(hostname, DnsRecordType.A, nextAddr, promise)) {
|
||||
// Use the same server for both CNAME queries
|
||||
DnsServerAddressStream stream = DnsServerAddresses.singleton(getNameServers(cname).next()).stream();
|
||||
|
||||
if (parent.supportsARecords() && !query(hostname, DnsRecordType.A, stream, promise)) {
|
||||
return;
|
||||
}
|
||||
if (parent.isCnameFollowAAAARecords()) {
|
||||
query(hostname, DnsRecordType.AAAA, nextAddr, promise);
|
||||
if (parent.supportsAAAARecords()) {
|
||||
query(hostname, DnsRecordType.AAAA, stream, promise);
|
||||
}
|
||||
}
|
||||
|
||||
private boolean query(String hostname, DnsRecordType type, final InetSocketAddress nextAddr, Promise<T> promise) {
|
||||
private boolean query(String hostname, DnsRecordType type, DnsServerAddressStream nextAddr, Promise<T> promise) {
|
||||
final DnsQuestion question;
|
||||
try {
|
||||
question = new DefaultDnsQuestion(hostname, type);
|
||||
|
|
@ -559,4 +738,118 @@ abstract class DnsNameResolverContext<T> {
|
|||
trace.append("Caused by: ");
|
||||
trace.append(cause);
|
||||
}
|
||||
|
||||
/**
|
||||
* Holds the closed DNS Servers for a domain.
|
||||
*/
|
||||
private static final class AuthoritativeNameServerList {
|
||||
|
||||
private final String questionName;
|
||||
|
||||
// We not expect the linked-list to be very long so a double-linked-list is overkill.
|
||||
private AuthoritativeNameServer head;
|
||||
private int count;
|
||||
|
||||
AuthoritativeNameServerList(String questionName) {
|
||||
this.questionName = questionName.toLowerCase(Locale.US);
|
||||
}
|
||||
|
||||
void add(DnsRecord r) {
|
||||
if (r.type() != DnsRecordType.NS || !(r instanceof DnsRawRecord)) {
|
||||
return;
|
||||
}
|
||||
|
||||
// Only include servers that serve the correct domain.
|
||||
if (questionName.length() < r.name().length()) {
|
||||
return;
|
||||
}
|
||||
|
||||
String recordName = r.name().toLowerCase(Locale.US);
|
||||
|
||||
int dots = 0;
|
||||
for (int a = recordName.length() - 1, b = questionName.length() - 1; a >= 0; a--, b--) {
|
||||
char c = recordName.charAt(a);
|
||||
if (questionName.charAt(b) != c) {
|
||||
return;
|
||||
}
|
||||
if (c == '.') {
|
||||
dots++;
|
||||
}
|
||||
}
|
||||
|
||||
if (head != null && head.dots > dots) {
|
||||
// We already have a closer match so ignore this one, no need to parse the domainName etc.
|
||||
return;
|
||||
}
|
||||
|
||||
final ByteBuf recordContent = ((ByteBufHolder) r).content();
|
||||
final String domainName = decodeDomainName(recordContent);
|
||||
if (domainName == null) {
|
||||
// Could not be parsed, ignore.
|
||||
return;
|
||||
}
|
||||
|
||||
// We are only interested in preserving the nameservers which are the closest to our qName, so ensure
|
||||
// we drop servers that have a smaller dots count.
|
||||
if (head == null || head.dots < dots) {
|
||||
count = 1;
|
||||
head = new AuthoritativeNameServer(dots, recordName, domainName);
|
||||
} else if (head.dots == dots) {
|
||||
AuthoritativeNameServer serverName = head;
|
||||
while (serverName.next != null) {
|
||||
serverName = serverName.next;
|
||||
}
|
||||
serverName.next = new AuthoritativeNameServer(dots, recordName, domainName);
|
||||
count++;
|
||||
}
|
||||
}
|
||||
|
||||
// Just walk the linked-list and mark the entry as removed when matched, so next lookup will need to process
|
||||
// one node less.
|
||||
AuthoritativeNameServer remove(String nsName) {
|
||||
AuthoritativeNameServer serverName = head;
|
||||
|
||||
while (serverName != null) {
|
||||
if (!serverName.removed && serverName.nsName.equalsIgnoreCase(nsName)) {
|
||||
serverName.removed = true;
|
||||
return serverName;
|
||||
}
|
||||
serverName = serverName.next;
|
||||
}
|
||||
return null;
|
||||
}
|
||||
|
||||
int size() {
|
||||
return count;
|
||||
}
|
||||
}
|
||||
|
||||
static final class AuthoritativeNameServer {
|
||||
final int dots;
|
||||
final String nsName;
|
||||
final String domainName;
|
||||
|
||||
AuthoritativeNameServer next;
|
||||
boolean removed;
|
||||
|
||||
AuthoritativeNameServer(int dots, String domainName, String nsName) {
|
||||
this.dots = dots;
|
||||
this.nsName = nsName;
|
||||
this.domainName = domainName;
|
||||
}
|
||||
|
||||
/**
|
||||
* Returns {@code true} if its a root server.
|
||||
*/
|
||||
boolean isRootServer() {
|
||||
return dots == 1;
|
||||
}
|
||||
|
||||
/**
|
||||
* The domain for which the {@link AuthoritativeNameServer} is responsible.
|
||||
*/
|
||||
String domainName() {
|
||||
return domainName;
|
||||
}
|
||||
}
|
||||
}
|
||||
|
|
|
|||
|
|
@ -40,9 +40,9 @@ public abstract class DnsServerAddresses {
|
|||
private static final List<InetSocketAddress> DEFAULT_NAME_SERVER_LIST;
|
||||
private static final InetSocketAddress[] DEFAULT_NAME_SERVER_ARRAY;
|
||||
private static final DnsServerAddresses DEFAULT_NAME_SERVERS;
|
||||
static final int DNS_PORT = 53;
|
||||
|
||||
static {
|
||||
final int DNS_PORT = 53;
|
||||
final List<InetSocketAddress> defaultNameServers = new ArrayList<InetSocketAddress>(2);
|
||||
try {
|
||||
Class<?> configClass = Class.forName("sun.net.dns.ResolverConfiguration");
|
||||
|
|
|
|||
|
|
@ -18,8 +18,11 @@ package io.netty.resolver.dns;
|
|||
import io.netty.buffer.ByteBuf;
|
||||
import io.netty.buffer.ByteBufHolder;
|
||||
import io.netty.channel.AddressedEnvelope;
|
||||
import io.netty.channel.EventLoop;
|
||||
import io.netty.channel.EventLoopGroup;
|
||||
import io.netty.channel.ReflectiveChannelFactory;
|
||||
import io.netty.channel.nio.NioEventLoopGroup;
|
||||
import io.netty.channel.socket.DatagramChannel;
|
||||
import io.netty.channel.socket.InternetProtocolFamily;
|
||||
import io.netty.channel.socket.nio.NioDatagramChannel;
|
||||
import io.netty.handler.codec.dns.DefaultDnsQuestion;
|
||||
|
|
@ -29,10 +32,17 @@ import io.netty.handler.codec.dns.DnsResponse;
|
|||
import io.netty.handler.codec.dns.DnsResponseCode;
|
||||
import io.netty.handler.codec.dns.DnsSection;
|
||||
import io.netty.util.NetUtil;
|
||||
import io.netty.resolver.HostsFileEntriesResolver;
|
||||
import io.netty.util.concurrent.Future;
|
||||
import io.netty.util.internal.StringUtil;
|
||||
import io.netty.util.internal.logging.InternalLogger;
|
||||
import io.netty.util.internal.logging.InternalLoggerFactory;
|
||||
import org.apache.directory.server.dns.messages.DnsMessage;
|
||||
import org.apache.directory.server.dns.messages.RecordClass;
|
||||
import org.apache.directory.server.dns.messages.RecordType;
|
||||
import org.apache.directory.server.dns.messages.ResourceRecord;
|
||||
import org.apache.directory.server.dns.messages.ResourceRecordModifier;
|
||||
import org.apache.directory.server.dns.store.DnsAttribute;
|
||||
import org.junit.AfterClass;
|
||||
import org.junit.BeforeClass;
|
||||
import org.junit.Test;
|
||||
|
|
@ -50,12 +60,16 @@ import java.util.List;
|
|||
import java.util.Map;
|
||||
import java.util.Map.Entry;
|
||||
import java.util.Set;
|
||||
import java.util.concurrent.TimeUnit;
|
||||
|
||||
import static org.hamcrest.Matchers.greaterThan;
|
||||
import static org.hamcrest.Matchers.hasSize;
|
||||
import static org.hamcrest.Matchers.hasToString;
|
||||
import static org.hamcrest.Matchers.instanceOf;
|
||||
import static org.hamcrest.Matchers.is;
|
||||
import static org.junit.Assert.assertEquals;
|
||||
import static org.junit.Assert.assertNotNull;
|
||||
import static org.junit.Assert.assertNull;
|
||||
import static org.junit.Assert.assertThat;
|
||||
import static org.junit.Assert.fail;
|
||||
|
||||
|
|
@ -599,6 +613,72 @@ public class DnsNameResolverTest {
|
|||
}
|
||||
}
|
||||
|
||||
@Test
|
||||
public void testRecursiveResolveNoCache() throws Exception {
|
||||
testRecursiveResolveCache(false);
|
||||
}
|
||||
|
||||
@Test
|
||||
public void testRecursiveResolveCache() throws Exception {
|
||||
testRecursiveResolveCache(true);
|
||||
}
|
||||
|
||||
private static void testRecursiveResolveCache(boolean cache) throws Exception {
|
||||
final String hostname = "some.record.netty.io";
|
||||
final String hostname2 = "some2.record.netty.io";
|
||||
|
||||
final TestDnsServer dnsServerAuthority = new TestDnsServer(new HashSet<String>(
|
||||
Arrays.asList(hostname, hostname2)));
|
||||
dnsServerAuthority.start();
|
||||
|
||||
TestDnsServer dnsServer = new RedirectingTestDnsServer(hostname,
|
||||
dnsServerAuthority.localAddress().getAddress().getHostAddress());
|
||||
dnsServer.start();
|
||||
|
||||
TestDnsCache nsCache = new TestDnsCache(cache ? new DefaultDnsCache() : NoopDnsCache.INSTANCE);
|
||||
EventLoopGroup group = new NioEventLoopGroup(1);
|
||||
DnsNameResolver resolver = new DnsNameResolver(
|
||||
group.next(), new ReflectiveChannelFactory<DatagramChannel>(NioDatagramChannel.class),
|
||||
DnsServerAddresses.singleton(dnsServer.localAddress()), NoopDnsCache.INSTANCE, nsCache,
|
||||
3000, new InternetProtocolFamily[] { InternetProtocolFamily.IPv4 }, true, 10,
|
||||
true, 4096, false, HostsFileEntriesResolver.DEFAULT,
|
||||
DnsNameResolver.DEFAULT_SEACH_DOMAINS, 0, true) {
|
||||
@Override
|
||||
int dnsRedirectPort(InetAddress server) {
|
||||
return server.equals(dnsServerAuthority.localAddress().getAddress()) ?
|
||||
dnsServerAuthority.localAddress().getPort() : DnsServerAddresses.DNS_PORT;
|
||||
}
|
||||
};
|
||||
|
||||
try {
|
||||
resolver.resolveAll(hostname).syncUninterruptibly();
|
||||
|
||||
if (cache) {
|
||||
assertNull(nsCache.cache.get("io.", null));
|
||||
assertNull(nsCache.cache.get("netty.io.", null));
|
||||
List<DnsCacheEntry> entries = nsCache.cache.get("record.netty.io.", null);
|
||||
assertEquals(1, entries.size());
|
||||
|
||||
assertNull(nsCache.cache.get(hostname, null));
|
||||
|
||||
// Test again via cache.
|
||||
resolver.resolveAll(hostname).syncUninterruptibly();
|
||||
resolver.resolveAll(hostname2).syncUninterruptibly();
|
||||
|
||||
// Check that it only queried the cache for record.netty.io.
|
||||
assertNull(nsCache.cacheHits.get("io."));
|
||||
assertNull(nsCache.cacheHits.get("netty.io."));
|
||||
assertNotNull(nsCache.cacheHits.get("record.netty.io."));
|
||||
assertNull(nsCache.cacheHits.get("some.record.netty.io."));
|
||||
}
|
||||
} finally {
|
||||
resolver.close();
|
||||
group.shutdownGracefully(0, 0, TimeUnit.SECONDS);
|
||||
dnsServer.stop();
|
||||
dnsServerAuthority.stop();
|
||||
}
|
||||
}
|
||||
|
||||
private static void resolve(DnsNameResolver resolver, Map<String, Future<InetAddress>> futures, String hostname) {
|
||||
futures.put(hostname, resolver.resolve(hostname));
|
||||
}
|
||||
|
|
@ -609,4 +689,94 @@ public class DnsNameResolverTest {
|
|||
String hostname) throws Exception {
|
||||
futures.put(hostname, resolver.query(new DefaultDnsQuestion(hostname, DnsRecordType.MX)));
|
||||
}
|
||||
|
||||
private static final class TestDnsCache implements DnsCache {
|
||||
private final DnsCache cache;
|
||||
final Map<String, List<DnsCacheEntry>> cacheHits = new HashMap<String, List<DnsCacheEntry>>();
|
||||
|
||||
TestDnsCache(DnsCache cache) {
|
||||
this.cache = cache;
|
||||
}
|
||||
|
||||
@Override
|
||||
public void clear() {
|
||||
cache.clear();
|
||||
}
|
||||
|
||||
@Override
|
||||
public boolean clear(String hostname) {
|
||||
return cache.clear(hostname);
|
||||
}
|
||||
|
||||
@Override
|
||||
public List<DnsCacheEntry> get(String hostname, DnsRecord[] additionals) {
|
||||
List<DnsCacheEntry> cacheEntries = cache.get(hostname, additionals);
|
||||
cacheHits.put(hostname, cacheEntries);
|
||||
return cacheEntries;
|
||||
}
|
||||
|
||||
@Override
|
||||
public void cache(
|
||||
String hostname, DnsRecord[] additionals, InetAddress address, long originalTtl, EventLoop loop) {
|
||||
cache.cache(hostname, additionals, address, originalTtl, loop);
|
||||
}
|
||||
|
||||
@Override
|
||||
public void cache(
|
||||
String hostname, DnsRecord[] additionals, Throwable cause, EventLoop loop) {
|
||||
cache.cache(hostname, additionals, cause, loop);
|
||||
}
|
||||
}
|
||||
|
||||
private static class RedirectingTestDnsServer extends TestDnsServer {
|
||||
|
||||
private final String dnsAddress;
|
||||
private final String domain;
|
||||
|
||||
RedirectingTestDnsServer(String domain, String dnsAddress) {
|
||||
super(Collections.singleton(domain));
|
||||
this.domain = domain;
|
||||
this.dnsAddress = dnsAddress;
|
||||
}
|
||||
|
||||
@Override
|
||||
protected DnsMessage filterMessage(DnsMessage message) {
|
||||
// Clear the answers as we want to add our own stuff to test dns redirects.
|
||||
message.getAnswerRecords().clear();
|
||||
|
||||
String name = domain;
|
||||
for (int i = 0 ;; i++) {
|
||||
int idx = name.indexOf('.');
|
||||
if (idx <= 0) {
|
||||
break;
|
||||
}
|
||||
name = name.substring(idx + 1); // skip the '.' as well.
|
||||
String dnsName = "dns" + idx + '.' + domain;
|
||||
message.getAuthorityRecords().add(newNsRecord(name, dnsName));
|
||||
message.getAdditionalRecords().add(newARecord(dnsName, i == 0 ? dnsAddress : "1.2.3." + idx));
|
||||
}
|
||||
|
||||
return message;
|
||||
}
|
||||
|
||||
private static ResourceRecord newARecord(String dnsname, String ipAddress) {
|
||||
ResourceRecordModifier rm = new ResourceRecordModifier();
|
||||
rm.setDnsClass(RecordClass.IN);
|
||||
rm.setDnsName(dnsname);
|
||||
rm.setDnsTtl(100);
|
||||
rm.setDnsType(RecordType.A);
|
||||
rm.put(DnsAttribute.IP_ADDRESS, ipAddress);
|
||||
return rm.getEntry();
|
||||
}
|
||||
|
||||
private static ResourceRecord newNsRecord(String dnsname, String domainName) {
|
||||
ResourceRecordModifier rm = new ResourceRecordModifier();
|
||||
rm.setDnsClass(RecordClass.IN);
|
||||
rm.setDnsName(dnsname);
|
||||
rm.setDnsTtl(100);
|
||||
rm.setDnsType(RecordType.NS);
|
||||
rm.put(DnsAttribute.DOMAIN_NAME, domainName);
|
||||
return rm.getEntry();
|
||||
}
|
||||
}
|
||||
}
|
||||
|
|
|
|||
|
|
@ -54,7 +54,7 @@ import java.util.List;
|
|||
import java.util.Map;
|
||||
import java.util.Set;
|
||||
|
||||
final class TestDnsServer extends DnsServer {
|
||||
class TestDnsServer extends DnsServer {
|
||||
private static final Map<String, byte[]> BYTES = new HashMap<String, byte[]>();
|
||||
private static final String[] IPV6_ADDRESSES;
|
||||
|
||||
|
|
@ -74,7 +74,7 @@ final class TestDnsServer extends DnsServer {
|
|||
private final RecordStore store;
|
||||
|
||||
TestDnsServer(Set<String> domains) {
|
||||
this.store = new TestRecordStore(domains);
|
||||
this(new TestRecordStore(domains));
|
||||
}
|
||||
|
||||
TestDnsServer(RecordStore store) {
|
||||
|
|
@ -83,7 +83,7 @@ final class TestDnsServer extends DnsServer {
|
|||
|
||||
@Override
|
||||
public void start() throws IOException {
|
||||
InetSocketAddress address = new InetSocketAddress(NetUtil.LOCALHOST4, 50000);
|
||||
InetSocketAddress address = new InetSocketAddress(NetUtil.LOCALHOST4, 0);
|
||||
UdpTransport transport = new UdpTransport(address.getHostName(), address.getPort());
|
||||
setTransports(transport);
|
||||
|
||||
|
|
@ -108,10 +108,14 @@ final class TestDnsServer extends DnsServer {
|
|||
return (InetSocketAddress) getTransports()[0].getAcceptor().getLocalAddress();
|
||||
}
|
||||
|
||||
protected DnsMessage filterMessage(DnsMessage message) {
|
||||
return message;
|
||||
}
|
||||
|
||||
/**
|
||||
* {@link ProtocolCodecFactory} which allows to test AAAA resolution.
|
||||
*/
|
||||
private static final class TestDnsProtocolUdpCodecFactory implements ProtocolCodecFactory {
|
||||
private final class TestDnsProtocolUdpCodecFactory implements ProtocolCodecFactory {
|
||||
private final DnsMessageEncoder encoder = new DnsMessageEncoder();
|
||||
private final TestAAAARecordEncoder recordEncoder = new TestAAAARecordEncoder();
|
||||
|
||||
|
|
@ -122,7 +126,7 @@ final class TestDnsServer extends DnsServer {
|
|||
@Override
|
||||
public void encode(IoSession session, Object message, ProtocolEncoderOutput out) {
|
||||
IoBuffer buf = IoBuffer.allocate(1024);
|
||||
DnsMessage dnsMessage = (DnsMessage) message;
|
||||
DnsMessage dnsMessage = filterMessage((DnsMessage) message);
|
||||
encoder.encode(buf, dnsMessage);
|
||||
for (ResourceRecord record : dnsMessage.getAnswerRecords()) {
|
||||
// This is a hack to allow to also test for AAAA resolution as DnsMessageEncoder
|
||||
|
|
@ -150,7 +154,7 @@ final class TestDnsServer extends DnsServer {
|
|||
return new DnsUdpDecoder();
|
||||
}
|
||||
|
||||
private static final class TestAAAARecordEncoder extends ResourceRecordEncoder {
|
||||
private final class TestAAAARecordEncoder extends ResourceRecordEncoder {
|
||||
|
||||
@Override
|
||||
protected void putResourceRecordData(IoBuffer ioBuffer, ResourceRecord resourceRecord) {
|
||||
|
|
|
|||
Loading…
Reference in New Issue
Block a user