Resolve RFC 6761 localhost names to loopback
Per section 6.3, HostResolverImpl should recognize localhost names as
special and resolve as loopback without sending the query over the
network.
This CL also modifies IsLocalhost() to allow trailing dots (bug 460331),
so that IsLocalhost() can be used to detect localhost names that should
resolve to loopback.
BUG=496479,460331
Review URL: https://codereview.chromium.org/1177933002
Cr-Commit-Position: refs/heads/master@{#335402}
diff --git a/net/dns/host_resolver_impl.cc b/net/dns/host_resolver_impl.cc
index a074c3e..0e2de32 100644
--- a/net/dns/host_resolver_impl.cc
+++ b/net/dns/host_resolver_impl.cc
@@ -74,8 +74,6 @@
// Minimum TTL for successful resolutions with DnsTask.
const unsigned kMinimumTTLSeconds = kCacheEntryTTLSeconds;
-const char kLocalhost[] = "localhost.";
-
// Time between IPv6 probes, i.e. for how long results of each IPv6 probe are
// cached.
const int kIPv6ProbePeriodMs = 1000;
@@ -1318,13 +1316,7 @@
}
void AddRequest(scoped_ptr<Request> req) {
- // .localhost queries are redirected to "localhost." to make sure
- // that they are never sent out on the network, per RFC 6761.
- if (IsLocalhostTLD(req->info().hostname())) {
- DCHECK_EQ(key_.hostname, kLocalhost);
- } else {
- DCHECK_EQ(key_.hostname, req->info().hostname());
- }
+ DCHECK_EQ(key_.hostname, req->info().hostname());
req->set_job(this);
priority_tracker_.Add(req->priority());
@@ -1997,6 +1989,10 @@
source_net_log.AddEvent(NetLog::TYPE_HOST_RESOLVER_IMPL_HOSTS_HIT);
return OK;
}
+
+ if (ServeLocalhost(key, info, addresses))
+ return OK;
+
return ERR_DNS_CACHE_MISS;
}
@@ -2159,6 +2155,35 @@
return !addresses->empty();
}
+bool HostResolverImpl::ServeLocalhost(const Key& key,
+ const RequestInfo& info,
+ AddressList* addresses) {
+ AddressList resolved_addresses;
+ if (!ResolveLocalHostname(key.hostname, info.port(), &resolved_addresses))
+ return false;
+
+ addresses->clear();
+
+ for (const auto& address : resolved_addresses) {
+ // Include the address if:
+ // - caller didn't specify an address family, or
+ // - caller specifically asked for the address family of this address, or
+ // - this is an IPv6 address and caller specifically asked for IPv4 due
+ // to lack of detected IPv6 support. (See SystemHostResolverCall for
+ // rationale).
+ if (key.address_family == ADDRESS_FAMILY_UNSPECIFIED ||
+ key.address_family == address.GetFamily() ||
+ (address.GetFamily() == ADDRESS_FAMILY_IPV6 &&
+ key.address_family == ADDRESS_FAMILY_IPV4 &&
+ (key.host_resolver_flags &
+ HOST_RESOLVER_DEFAULT_FAMILY_SET_DUE_TO_NO_IPV6))) {
+ addresses->push_back(address);
+ }
+ }
+
+ return true;
+}
+
void HostResolverImpl::CacheResult(const Key& key,
const HostCache::Entry& entry,
base::TimeDelta ttl) {
@@ -2205,13 +2230,7 @@
}
}
- std::string hostname = info.hostname();
- // Redirect .localhost queries to "localhost." to make sure that they
- // are never sent out on the network, per RFC 6761.
- if (IsLocalhostTLD(info.hostname()))
- hostname = kLocalhost;
-
- return Key(hostname, effective_address_family, effective_flags);
+ return Key(info.hostname(), effective_address_family, effective_flags);
}
bool HostResolverImpl::IsIPv6Reachable(const BoundNetLog& net_log) {
