PairingAuthenticator implementation and plumbing.

remoting/protocol/pairing_client_authenticator.cc

+// Copyright 2013 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.
+
+#include "remoting/protocol/pairing_client_authenticator.h"
+
+#include "base/bind.h"
+#include "base/logging.h"
+#include "remoting/base/constants.h"
+#include "remoting/base/rsa_key_pair.h"
+#include "remoting/protocol/authentication_method.h"
+#include "remoting/protocol/channel_authenticator.h"
+#include "remoting/protocol/v2_authenticator.h"
+#include "third_party/libjingle/source/talk/xmllite/xmlelement.h"
+
+namespace remoting {
+namespace protocol {
+
+PairingClientAuthenticator::PairingClientAuthenticator(
+    const std::string& client_id,
+    const std::string& paired_secret,
+    const FetchSecretCallback& fetch_pin_callback,
+    const std::string& authentication_tag)
+    : sent_client_id_(false),
+      client_id_(client_id),
+      paired_secret_(paired_secret),
+      fetch_pin_callback_(fetch_pin_callback),
+      authentication_tag_(authentication_tag),
+      weak_factory_(this) {
+  v2_authenticator_ = V2Authenticator::CreateForClient(
+      paired_secret_, MESSAGE_READY);
+  using_paired_secret_ = true;
+}
+
+void PairingClientAuthenticator::CreateV2AuthenticatorWithPIN(
+    State initial_state,
+    const SetAuthenticatorCallback& set_authenticator_callback) {
+  SecretFetchedCallback callback = base::Bind(
+      &PairingClientAuthenticator::OnPinFetched,
+      weak_factory_.GetWeakPtr(), initial_state, set_authenticator_callback);
+  fetch_pin_callback_.Run(callback);
+}
+
+scoped_ptr<Authenticator>
+PairingClientAuthenticator::CreateV2AuthenticatorFromInitialMessage(
+    const buzz::XmlElement* message) {
+  // The client always initiates the pairing protocol, so it will never be
+  // asked to create a V2 authenticator based on the first message.
+  NOTREACHED();
+  return scoped_ptr<Authenticator>();
+}
+
+void PairingClientAuthenticator::AmendProtocolMessage(
+    buzz::XmlElement* message) {
+  // If the client id and secret have not yet been sent, do so now. Note that
+  // in this case the V2Authenticator is being used optimistically to send the
+  // first message of the SPAKE exchange since we don't yet know whether or not
+  // the host will accept the client id or request that we fall back to the PIN.
+  if (!sent_client_id_) {
+    buzz::XmlElement* pairing_tag = new buzz::XmlElement(kPairingInfoTag);
+    pairing_tag->AddAttr(kClientIdAttribute, client_id_);
+    message->AddElement(pairing_tag);
+    sent_client_id_ = true;
+  }
+}
+
+void PairingClientAuthenticator::OnPinFetched(
+    State initial_state,
+    const SetAuthenticatorCallback& callback,
+    const std::string& pin) {
+  callback.Run(V2Authenticator::CreateForClient(
+      AuthenticationMethod::ApplyHashFunction(
+          AuthenticationMethod::HMAC_SHA256,
+          authentication_tag_, pin),
+      initial_state));
+}
+
+}  // namespace protocol
+}  // namespace remoting