Automatically update LogDnsClient's DNS config

components/certificate_transparency/log_dns_client.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "components/certificate_transparency/log_dns_client.h"
 
 #include <sstream>
 
 #include "base/bind.h"
 #include "base/location.h"
 #include "base/logging.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_util.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "base/time/time.h"
+#include "base/values.h"
 #include "components/base32/base32.h"
 #include "crypto/sha2.h"
 #include "net/base/net_errors.h"
 #include "net/cert/merkle_audit_proof.h"
 #include "net/dns/dns_client.h"
+#include "net/dns/dns_config_service.h"
 #include "net/dns/dns_protocol.h"
 #include "net/dns/dns_response.h"
 #include "net/dns/dns_transaction.h"
 #include "net/dns/record_parsed.h"
 #include "net/dns/record_rdata.h"
 
 namespace certificate_transparency {
 
 namespace {
 
@@ skipping 48 matching lines @@
 }
 
 }  // namespace
 
 LogDnsClient::LogDnsClient(std::unique_ptr<net::DnsClient> dns_client,
                            const net::BoundNetLog& net_log)
     : dns_client_(std::move(dns_client)),
       net_log_(net_log),
       weak_ptr_factory_(this) {
   CHECK(dns_client_);
+  net::NetworkChangeNotifier::AddDNSObserver(this);
+  UpdateDnsConfig();
 }
 
-LogDnsClient::~LogDnsClient() {}
+LogDnsClient::~LogDnsClient() {
+  net::NetworkChangeNotifier::RemoveDNSObserver(this);
+}
+
+void LogDnsClient::OnDNSChanged() {
+  UpdateDnsConfig();
+}
+
+void LogDnsClient::OnInitialDNSConfigRead() {
+  UpdateDnsConfig();
+}
 
 void LogDnsClient::QueryLeafIndex(base::StringPiece domain_for_log,
                                   base::StringPiece leaf_hash,
                                   const LeafIndexCallback& callback) {
   if (domain_for_log.empty() || leaf_hash.size() != crypto::kSHA256Length) {
     base::ThreadTaskRunnerHandle::Get()->PostTask(
         FROM_HERE, base::Bind(callback, net::Error::ERR_INVALID_ARGUMENT, 0));
     return;
   }
 
@@ skipping 182 matching lines @@
     QueryAuditProofNodes(std::move(proof), domain_for_log, tree_size,
                          audit_path_nodes_received, query.callback);
     return;
   }
 
   base::ThreadTaskRunnerHandle::Get()->PostTask(
       FROM_HERE,
       base::Bind(query.callback, net::OK, base::Passed(std::move(proof))));
 }
 
+void LogDnsClient::UpdateDnsConfig() {
+  net::DnsConfig config;
+  net::NetworkChangeNotifier::GetDnsConfig(&config);
+  if (config.IsValid())
+    dns_client_->SetConfig(config);
+}
+
 }  // namespace certificate_transparency