// Copyright (c) 2012 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 REMOTING_HOST_DNS_BLACKHOLE_CHECKER_H_
#define REMOTING_HOST_DNS_BLACKHOLE_CHECKER_H_
#include "net/url_request/url_fetcher_delegate.h"
#include "base/callback.h"
namespace net {
class URLRequestContextGetter;
} // namespace net
namespace remoting {
// This is the default prefix that is prepended to the kTalkGadgetUrl to form
// the complete talkgadget URL used by the host. Policy settings allow admins
// to change the prefix that is used.
extern const char kDefaultHostTalkGadgetPrefix[];
class DnsBlackholeChecker : public net::URLFetcherDelegate {
public:
DnsBlackholeChecker(
scoped_refptr<net::URLRequestContextGetter> url_request_context_getter,
std::string talkgadget_prefix);
virtual ~DnsBlackholeChecker();
// net::URLFetcherDelegate interface.
virtual void OnURLFetchComplete(const net::URLFetcher* source) OVERRIDE;
// Initiates a check the verify that the host talkgadget has not been "DNS
// blackholed" to prevent connections. If this is called again before the
// callback has been called, then the second call is ignored.
void CheckForDnsBlackhole(const base::Callback<void(bool)>& callback);
private:
// URL request context getter to use to create the URL fetcher.
scoped_refptr<net::URLRequestContextGetter> url_request_context_getter_;
// URL fetcher used to verify access to the host talkgadget.
scoped_ptr<net::URLFetcher> url_fetcher_;
// The string pre-pended to '.talkgadget.google.com' to create the full
// talkgadget domain name for the host.
std::string talkgadget_prefix_;
// Called with the results of the connection check.
base::Callback<void(bool)> callback_;
DISALLOW_COPY_AND_ASSIGN(DnsBlackholeChecker);
};
} // namespace remoting
#endif // REMOTING_HOST_DNS_BLACKHOLE_CHECKER_H_