net: perform a non-A DNS lookup for HTTPS hosts.

Since SSLHostInfo is enabled by default now, this will cause a DNS
lookup for a random RR type (13172) for each HTTPS host. (Although many
of these lookups will hit the in-process cache. Also, this won't do
anything on non-Linux machines because I haven't gotten the DNS lookup
code working on them yet.)

At some point in the future we'll probably want to do these lookups in
order to get information for certificate validation. This change just
exists so that we can measure how long these lookups take.

BUG=none
TEST=none

http://codereview.chromium.org/6041004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@70631 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 33 insertions, 2 deletions

diff --git a/net/socket/ssl_host_info.cc b/net/socket/ssl_host_info.cc
index ccfe7a53..7a8209a 100644
--- a/net/socket/ssl_host_info.cc
+++ b/net/socket/ssl_host_info.cc
@@ -7,6 +7,8 @@
 #include "base/metrics/histogram.h"
 #include "base/pickle.h"
 #include "base/string_piece.h"
+#include "net/base/dns_util.h"
+#include "net/base/dnsrr_resolver.h"
 #include "net/base/ssl_config_service.h"
 #include "net/base/x509_certificate.h"
 #include "net/socket/ssl_client_socket.h"
@@ -40,11 +42,31 @@ SSLHostInfo::SSLHostInfo(
       verifier_(cert_verifier),
       callback_(new CancelableCompletionCallback<SSLHostInfo>(
                         ALLOW_THIS_IN_INITIALIZER_LIST(this),
-                        &SSLHostInfo::VerifyCallback)) {
+                        &SSLHostInfo::VerifyCallback)),
+      dnsrr_resolver_(NULL),
+      dns_callback_(NULL),
+      dns_handle_(DnsRRResolver::kInvalidHandle) {
   state_.npn_valid = false;
 }
 
-SSLHostInfo::~SSLHostInfo() {}
+SSLHostInfo::~SSLHostInfo() {
+  if (dns_handle_ != DnsRRResolver::kInvalidHandle) {
+    dnsrr_resolver_->CancelResolve(dns_handle_);
+    delete dns_callback_;
+  }
+}
+
+void SSLHostInfo::StartDnsLookup(DnsRRResolver* dnsrr_resolver) {
+#if defined(OS_LINUX)
+  dnsrr_resolver_ = dnsrr_resolver;
+  dns_callback_ = NewCallback(this, &SSLHostInfo::DnsComplete);
+  dns_lookup_start_time_ = base::TimeTicks::Now();
+
+  dns_handle_ = dnsrr_resolver->Resolve(
+      hostname_, kDNS_CAA, DnsRRResolver::FLAG_WANT_DNSSEC, dns_callback_,
+      &dns_response_, 0, BoundNetLog());
+#endif
+}
 
 const SSLHostInfo::State& SSLHostInfo::state() const {
   return state_;
@@ -196,6 +218,15 @@ void SSLHostInfo::VerifyCallback(int rv) {
   }
 }
 
+void SSLHostInfo::DnsComplete(int rv) {
+  dns_handle_ = DnsRRResolver::kInvalidHandle;
+  dns_callback_ = NULL;
+
+  const base::TimeTicks now = base::TimeTicks::Now();
+  const base::TimeDelta elapsed = now - dns_lookup_start_time_;
+  UMA_HISTOGRAM_TIMES("Net.SSLHostInfoDNSLookup", elapsed);
+}
+
 SSLHostInfoFactory::~SSLHostInfoFactory() {}
 
 }  // namespace net