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      1 // Copyright 2013 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_PROTOCOL_THIRD_PARTY_CLIENT_AUTHENTICATOR_H_
      6 #define REMOTING_PROTOCOL_THIRD_PARTY_CLIENT_AUTHENTICATOR_H_
      7 
      8 #include <string>
      9 
     10 #include "base/callback.h"
     11 #include "base/memory/scoped_ptr.h"
     12 #include "base/memory/weak_ptr.h"
     13 #include "remoting/protocol/third_party_authenticator_base.h"
     14 #include "url/gurl.h"
     15 
     16 class GURL;
     17 
     18 namespace remoting {
     19 namespace protocol {
     20 
     21 // Implements the client side of the third party authentication mechanism.
     22 // The client authenticator expects a |token_url| and |scope| in the first
     23 // message from the host, then calls the |TokenFetcher| asynchronously to
     24 // request a |token| and |shared_secret| from that url. If the server requires
     25 // interactive authentication, the |TokenFetcher| implementation will show the
     26 // appropriate UI. Once the |TokenFetcher| returns, the client sends the |token|
     27 // to the host, and uses the |shared_secret| to create an underlying
     28 // |V2Authenticator|, which is used to establish the encrypted connection.
     29 class ThirdPartyClientAuthenticator : public ThirdPartyAuthenticatorBase {
     30  public:
     31   class TokenFetcher {
     32    public:
     33     // Callback passed to |FetchThirdPartyToken|, and called once the client
     34     // authentication finishes. |token| is an opaque string that should be sent
     35     // directly to the host. |shared_secret| should be used by the client to
     36     // create a V2Authenticator. In case of failure, the callback is called with
     37     // an empty |token| and |shared_secret|.
     38     typedef base::Callback<void(
     39         const std::string& token,
     40         const std::string& shared_secret)> TokenFetchedCallback;
     41 
     42     virtual ~TokenFetcher() {}
     43 
     44     // Fetches a third party token from |token_url|. |host_public_key| is sent
     45     // to the server so it can later authenticate the host. |scope| is a string
     46     // with a space-separated list of attributes for this connection (e.g.
     47     // "hostjid:abc (at) example.com/123 clientjid:def (at) example.org/456".
     48     // |token_fetched_callback| is called when the client authentication ends,
     49     // in the same thread |FetchThirdPartyToken| was originally called.
     50     // The request is canceled if the TokenFetcher is destroyed.
     51     virtual void FetchThirdPartyToken(
     52         const GURL& token_url,
     53         const std::string& scope,
     54         const TokenFetchedCallback& token_fetched_callback) = 0;
     55   };
     56 
     57   // Creates a third-party client authenticator for the host with the given
     58   // |host_public_key|. |token_fetcher| is used to get the authentication token.
     59   explicit ThirdPartyClientAuthenticator(
     60       scoped_ptr<TokenFetcher> token_fetcher);
     61   virtual ~ThirdPartyClientAuthenticator();
     62 
     63  protected:
     64   // ThirdPartyAuthenticator implementation.
     65   virtual void ProcessTokenMessage(
     66       const buzz::XmlElement* message,
     67       const base::Closure& resume_callback) OVERRIDE;
     68   virtual void AddTokenElements(buzz::XmlElement* message) OVERRIDE;
     69 
     70  private:
     71   void OnThirdPartyTokenFetched(const base::Closure& resume_callback,
     72                                 const std::string& third_party_token,
     73                                 const std::string& shared_secret);
     74 
     75   std::string token_;
     76   scoped_ptr<TokenFetcher> token_fetcher_;
     77 
     78   DISALLOW_COPY_AND_ASSIGN(ThirdPartyClientAuthenticator);
     79 };
     80 
     81 
     82 }  // namespace protocol
     83 }  // namespace remoting
     84 
     85 #endif  // REMOTING_PROTOCOL_THIRD_PARTY_CLIENT_AUTHENTICATOR_H_
     86