remoting/host/dns_blackhole_checker.h

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef REMOTING_HOST_DNS_BLACKHOLE_CHECKER_H_
   6 #define REMOTING_HOST_DNS_BLACKHOLE_CHECKER_H_
   7
   8 #include "net/url_request/url_fetcher_delegate.h"
   9
  10 #include "base/callback.h"
  11
  12 namespace net {
  13 class URLRequestContextGetter;
  14 }  // namespace net
  15
  16 namespace remoting {
  17
  18 // This is the default prefix that is prepended to the kTalkGadgetUrl to form
  19 // the complete talkgadget URL used by the host. Policy settings allow admins
  20 // to change the prefix that is used.
  21 extern const char kDefaultHostTalkGadgetPrefix[];
  22
  23 class DnsBlackholeChecker : public net::URLFetcherDelegate {
  24  public:
  25   DnsBlackholeChecker(
  26       scoped_refptr<net::URLRequestContextGetter> url_request_context_getter,
  27       std::string talkgadget_prefix);
  28   virtual ~DnsBlackholeChecker();
  29
  30   // net::URLFetcherDelegate interface.
  31   virtual void OnURLFetchComplete(const net::URLFetcher* source) OVERRIDE;
  32
  33   // Initiates a check the verify that the host talkgadget has not been "DNS
  34   // blackholed" to prevent connections. If this is called again before the
  35   // callback has been called, then the second call is ignored.
  36   void CheckForDnsBlackhole(const base::Callback<void(bool)>& callback);
  37
  38  private:
  39   // URL request context getter to use to create the URL fetcher.
  40   scoped_refptr<net::URLRequestContextGetter> url_request_context_getter_;
  41
  42   // URL fetcher used to verify access to the host talkgadget.
  43   scoped_ptr<net::URLFetcher> url_fetcher_;
  44
  45   // The string pre-pended to '.talkgadget.google.com' to create the full
  46   // talkgadget domain name for the host.
  47   std::string talkgadget_prefix_;
  48
  49   // Called with the results of the connection check.
  50   base::Callback<void(bool)> callback_;
  51
  52   DISALLOW_COPY_AND_ASSIGN(DnsBlackholeChecker);
  53 };
  54
  55 }  // namespace remoting
  56
  57 #endif  // REMOTING_HOST_DNS_BLACKHOLE_CHECKER_H_