Add a mechanism to disable IPv6....

net/base/host_resolver.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_H_
 #define NET_BASE_HOST_RESOLVER_H_
 
 #include <string>
 
 #include "base/ref_counted.h"
 #include "googleurl/src/gurl.h"
+#include "net/base/address_family.h"
 #include "net/base/completion_callback.h"
 
 class MessageLoop;
 
 namespace net {
 
 class AddressList;
 class HostCache;
 class LoadLog;
 
 // This class represents the task of resolving hostnames (or IP address
 // literal) to an AddressList object.
 //
 // HostResolver can handle multiple requests at a time, so when cancelling a
 // request the RequestHandle that was returned by Resolve() needs to be
 // given.  A simpler alternative for consumers that only have 1 outstanding
 // request at a time is to create a SingleRequestHostResolver wrapper around
 // HostResolver (which will automatically cancel the single request when it
 // goes out of scope).
 class HostResolver : public base::RefCountedThreadSafe<HostResolver> {
  public:
   // The parameters for doing a Resolve(). |hostname| and |port| are required,
   // the rest are optional (and have reasonable defaults).
   class RequestInfo {
    public:
     RequestInfo(const std::string& hostname, int port)
         : hostname_(hostname),
+          address_family_(ADDRESS_FAMILY_UNSPECIFIED),
           port_(port),
           allow_cached_response_(true),
           is_speculative_(false) {}
 
     const int port() const { return port_; }
     const std::string& hostname() const { return hostname_; }
 
+    AddressFamily address_family() const { return address_family_; }
+    void set_address_family(AddressFamily address_family) {
+      address_family_ = address_family;
+    }
+
     bool allow_cached_response() const { return allow_cached_response_; }
     void set_allow_cached_response(bool b) { allow_cached_response_ = b; }
 
     bool is_speculative() const { return is_speculative_; }
     void set_is_speculative(bool b) { is_speculative_ = b; }
 
     const GURL& referrer() const { return referrer_; }
     void set_referrer(const GURL& referrer) { referrer_ = referrer; }
 
    private:
     // The hostname to resolve.
     std::string hostname_;
 
+    // The address family to restrict results to.
+    AddressFamily address_family_;
+
     // The port number to set in the result's sockaddrs.
     int port_;
 
     // Whether it is ok to return a result from the host cache.
     bool allow_cached_response_;
 
     // Whether this request was started by the DNS prefetcher.
     bool is_speculative_;
 
     // Optional data for consumption by observers. This is the URL of the
@@ skipping 62 matching lines @@
   // Unregisters an observer previously added by AddObserver().
   virtual void RemoveObserver(Observer* observer) = 0;
 
   // Returns the host cache, or NULL if this implementation does not use
   // a HostCache.
   virtual HostCache* GetHostCache() = 0;
 
   // TODO(eroman): temp hack for http://crbug.com/18373
   virtual void Shutdown() = 0;
 
+  // Disables or enables support for IPv6 results.
+  virtual void DisableIPv6(bool disable_ipv6) {}
+
  protected:
   HostResolver() { }
 
  private:
   DISALLOW_COPY_AND_ASSIGN(HostResolver);
 };
 
 // This class represents the task of resolving a hostname (or IP address
 // literal) to an AddressList object.  It wraps HostResolver to resolve only a
 // single hostname at a time and cancels this request when going out of scope.
@@ skipping 32 matching lines @@
 };
 
 // Creates a HostResolver implementation that queries the underlying system.
 // (Except if a unit-test has changed the global HostResolverProc using
 // ScopedHostResolverProc to intercept requests to the system).
 HostResolver* CreateSystemHostResolver();
 
 }  // namespace net
 
 #endif  // NET_BASE_HOST_RESOLVER_H_