Refine IPv6 probe to require that the client has an IPv6 address on an interf...

net/base/host_resolver_impl.h

 // Copyright (c) 2006-2008 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.
 
 #ifndef NET_BASE_HOST_RESOLVER_IMPL_H_
 #define NET_BASE_HOST_RESOLVER_IMPL_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 71 matching lines @@
   // HostResolver methods:
   virtual int Resolve(const RequestInfo& info,
                       AddressList* addresses,
                       CompletionCallback* callback,
                       RequestHandle* out_req,
                       const BoundNetLog& net_log);
   virtual void CancelRequest(RequestHandle req);
   virtual void AddObserver(HostResolver::Observer* observer);
   virtual void RemoveObserver(HostResolver::Observer* observer);
 
-  virtual void SetDefaultAddressFamily(AddressFamily address_family) {
-    default_address_family_ = address_family;
-  }
+  // Set address family, and disable IPv6 probe support.
+  virtual void SetDefaultAddressFamily(AddressFamily address_family);
+
+  // Continuously observe whether IPv6 is supported, and set the allowable
+  // address family to IPv4 iff IPv6 is not supported.
+  void ProbeIPv6Support();
 
   virtual HostResolverImpl* GetAsHostResolverImpl() { return this; }
 
   // TODO(eroman): hack for http://crbug.com/15513
   void Shutdown();
 
   // Returns the cache this resolver uses, or NULL if caching is disabled.
   HostCache* cache() { return cache_.get(); }
 
   // Clears the request trace log.
@@ skipping 18 matching lines @@
   //                            before we start dropping requests. Dropped
   //                            requests fail with
   //                            ERR_HOST_RESOLVER_QUEUE_TOO_LARGE.
   void SetPoolConstraints(JobPoolIndex pool_index,
                           size_t max_outstanding_jobs,
                           size_t max_pending_requests);
 
  private:
   class Job;
   class JobPool;
+  class IPv6ProbeJob;
   class Request;
   class RequestsTrace;
   typedef std::vector<Request*> RequestsList;
   typedef HostCache::Key Key;
   typedef std::map<Key, scoped_refptr<Job> > JobMap;
   typedef std::vector<HostResolver::Observer*> ObserversList;
 
   // If any completion callbacks are pending when the resolver is destroyed,
   // the host resolutions are cancelled, and the completion callbacks will not
   // be called.
@@ skipping 29 matching lines @@
                        int error);
 
   // Called when a request has been cancelled.
   void OnCancelRequest(const BoundNetLog& net_log,
                        int request_id,
                        const RequestInfo& info);
 
   // NetworkChangeNotifier::Observer methods:
   virtual void OnIPAddressChanged();
 
+  // Notify IPv6ProbeJob not to call back, and discard reference to the job.
+  void DiscardIPv6ProbeJob();
+
+  // Callback from IPv6 probe activity.
+  void IPv6ProbeSetDefaultAddressFamily(AddressFamily address_family);
+
   // Returns true if the constraints for |pool| are met, and a new job can be
   // created for this pool.
   bool CanCreateJobForPool(const JobPool& pool) const;
 
   // Returns the index of the pool that request |req| maps to.
   static JobPoolIndex GetJobPoolIndexForRequest(const Request* req);
 
   JobPool* GetPoolForRequest(const Request* req) {
     return job_pools_[GetJobPoolIndexForRequest(req)];
   }
@@ skipping 48 matching lines @@
   // Address family to use when the request doesn't specify one.
   AddressFamily default_address_family_;
 
   // TODO(eroman): hack for http://crbug.com/15513
   bool shutdown_;
 
   NetworkChangeNotifier* const network_change_notifier_;
 
   scoped_refptr<RequestsTrace> requests_trace_;
 
+  // Indicate if probing is done after each network change event to set address
+  // family.
+  // When false, explicit setting of address family is used.
+  bool ipv6_probe_monitoring_;
+
+  // The last un-cancelled IPv6ProbeJob (if any).
+  scoped_refptr<IPv6ProbeJob> ipv6_probe_job_;
+
   DISALLOW_COPY_AND_ASSIGN(HostResolverImpl);
 };
 
 }  // namespace net
 
 #endif  // NET_BASE_HOST_RESOLVER_IMPL_H_