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_ 58
