Revert of Refactoring that removes P2PTransport and DtlsTransport classes.

webrtc/p2p/base/transport.h

Index: webrtc/p2p/base/transport.h
diff --git a/webrtc/p2p/base/transport.h b/webrtc/p2p/base/transport.h
new file mode 100644
index 0000000000000000000000000000000000000000..adef6533ea9b41c635cb2ec327c039f1d43f4431
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+++ b/webrtc/p2p/base/transport.h
@@ -0,0 +1,423 @@
+/*
+ *  Copyright 2004 The WebRTC Project Authors. All rights reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+// A Transport manages a set of named channels of the same type.
+//
+// Subclasses choose the appropriate class to instantiate for each channel;
+// however, this base class keeps track of the channels by name, watches their
+// state changes (in order to update the manager's state), and forwards
+// requests to begin connecting or to reset to each of the channels.
+//
+// On Threading:  Transport performs work solely on the network thread, and so
+// its methods should only be called on the network thread.
+//
+// Note: Subclasses must call DestroyChannels() in their own destructors.
+// It is not possible to do so here because the subclass destructor will
+// already have run.
+
+#ifndef WEBRTC_P2P_BASE_TRANSPORT_H_
+#define WEBRTC_P2P_BASE_TRANSPORT_H_
+
+#include <map>
+#include <memory>
+#include <string>
+#include <vector>
+
+#include "webrtc/base/constructormagic.h"
+#include "webrtc/base/optional.h"
+#include "webrtc/p2p/base/candidate.h"
+#include "webrtc/p2p/base/p2pconstants.h"
+#include "webrtc/p2p/base/sessiondescription.h"
+#include "webrtc/p2p/base/transportinfo.h"
+#include "webrtc/base/messagequeue.h"
+#include "webrtc/base/rtccertificate.h"
+#include "webrtc/base/sigslot.h"
+#include "webrtc/base/sslstreamadapter.h"
+
+namespace cricket {
+
+class PortAllocator;
+class TransportChannel;
+class TransportChannelImpl;
+
+typedef std::vector<Candidate> Candidates;
+
+// TODO(deadbeef): Unify with PeerConnectionInterface::IceConnectionState
+// once /talk/ and /webrtc/ are combined, and also switch to ENUM_NAME naming
+// style.
+enum IceConnectionState {
+  kIceConnectionConnecting = 0,
+  kIceConnectionFailed,
+  kIceConnectionConnected,  // Writable, but still checking one or more
+                            // connections
+  kIceConnectionCompleted,
+};
+
+enum DtlsTransportState {
+  // Haven't started negotiating.
+  DTLS_TRANSPORT_NEW = 0,
+  // Have started negotiating.
+  DTLS_TRANSPORT_CONNECTING,
+  // Negotiated, and has a secure connection.
+  DTLS_TRANSPORT_CONNECTED,
+  // Transport is closed.
+  DTLS_TRANSPORT_CLOSED,
+  // Failed due to some error in the handshake process.
+  DTLS_TRANSPORT_FAILED,
+};
+
+// TODO(deadbeef): Unify with PeerConnectionInterface::IceConnectionState
+// once /talk/ and /webrtc/ are combined, and also switch to ENUM_NAME naming
+// style.
+enum IceGatheringState {
+  kIceGatheringNew = 0,
+  kIceGatheringGathering,
+  kIceGatheringComplete,
+};
+
+enum ContinualGatheringPolicy {
+  // All port allocator sessions will stop after a writable connection is found.
+  GATHER_ONCE = 0,
+  // The most recent port allocator session will keep on running.
+  GATHER_CONTINUALLY,
+  // The most recent port allocator session will keep on running, and it will
+  // try to recover connectivity if the channel becomes disconnected.
+  GATHER_CONTINUALLY_AND_RECOVER,
+};
+
+// Stats that we can return about the connections for a transport channel.
+// TODO(hta): Rename to ConnectionStats
+struct ConnectionInfo {
+  ConnectionInfo()
+      : best_connection(false),
+        writable(false),
+        receiving(false),
+        timeout(false),
+        new_connection(false),
+        rtt(0),
+        sent_total_bytes(0),
+        sent_bytes_second(0),
+        sent_discarded_packets(0),
+        sent_total_packets(0),
+        sent_ping_requests_total(0),
+        sent_ping_requests_before_first_response(0),
+        sent_ping_responses(0),
+        recv_total_bytes(0),
+        recv_bytes_second(0),
+        recv_ping_requests(0),
+        recv_ping_responses(0),
+        key(NULL) {}
+
+  bool best_connection;        // Is this the best connection we have?
+  bool writable;               // Has this connection received a STUN response?
+  bool receiving;              // Has this connection received anything?
+  bool timeout;                // Has this connection timed out?
+  bool new_connection;         // Is this a newly created connection?
+  size_t rtt;                  // The STUN RTT for this connection.
+  size_t sent_total_bytes;     // Total bytes sent on this connection.
+  size_t sent_bytes_second;    // Bps over the last measurement interval.
+  size_t sent_discarded_packets;  // Number of outgoing packets discarded due to
+                                  // socket errors.
+  size_t sent_total_packets;  // Number of total outgoing packets attempted for
+                              // sending.
+  size_t sent_ping_requests_total;  // Number of STUN ping request sent.
+  size_t sent_ping_requests_before_first_response;  // Number of STUN ping
+  // sent before receiving the first response.
+  size_t sent_ping_responses;  // Number of STUN ping response sent.
+
+  size_t recv_total_bytes;     // Total bytes received on this connection.
+  size_t recv_bytes_second;    // Bps over the last measurement interval.
+  size_t recv_ping_requests;   // Number of STUN ping request received.
+  size_t recv_ping_responses;  // Number of STUN ping response received.
+  Candidate local_candidate;   // The local candidate for this connection.
+  Candidate remote_candidate;  // The remote candidate for this connection.
+  void* key;                   // A static value that identifies this conn.
+};
+
+// Information about all the connections of a channel.
+typedef std::vector<ConnectionInfo> ConnectionInfos;
+
+// Information about a specific channel
+struct TransportChannelStats {
+  int component = 0;
+  ConnectionInfos connection_infos;
+  int srtp_crypto_suite = rtc::SRTP_INVALID_CRYPTO_SUITE;
+  int ssl_cipher_suite = rtc::TLS_NULL_WITH_NULL_NULL;
+};
+
+// Information about all the channels of a transport.
+// TODO(hta): Consider if a simple vector is as good as a map.
+typedef std::vector<TransportChannelStats> TransportChannelStatsList;
+
+// Information about the stats of a transport.
+struct TransportStats {
+  std::string transport_name;
+  TransportChannelStatsList channel_stats;
+};
+
+// ICE Nomination mode.
+enum class NominationMode {
+  REGULAR,         // Nominate once per ICE restart (Not implemented yet).
+  AGGRESSIVE,      // Nominate every connection except that it will behave as if
+                   // REGULAR when the remote is an ICE-LITE endpoint.
+  SEMI_AGGRESSIVE  // Our current implementation of the nomination algorithm.
+                   // The details are described in P2PTransportChannel.
+};
+
+// Information about ICE configuration.
+// TODO(deadbeef): Use rtc::Optional to represent unset values, instead of
+// -1.
+struct IceConfig {
+  // The ICE connection receiving timeout value in milliseconds.
+  int receiving_timeout = -1;
+  // Time interval in milliseconds to ping a backup connection when the ICE
+  // channel is strongly connected.
+  int backup_connection_ping_interval = -1;
+
+  ContinualGatheringPolicy continual_gathering_policy = GATHER_ONCE;
+
+  bool gather_continually() const {
+    return continual_gathering_policy == GATHER_CONTINUALLY ||
+           continual_gathering_policy == GATHER_CONTINUALLY_AND_RECOVER;
+  }
+
+  // Whether we should prioritize Relay/Relay candidate when nothing
+  // is writable yet.
+  bool prioritize_most_likely_candidate_pairs = false;
+
+  // Writable connections are pinged at a slower rate once stablized.
+  int stable_writable_connection_ping_interval = -1;
+
+  // If set to true, this means the ICE transport should presume TURN-to-TURN
+  // candidate pairs will succeed, even before a binding response is received.
+  bool presume_writable_when_fully_relayed = false;
+
+  // Interval to check on all networks and to perform ICE regathering on any
+  // active network having no connection on it.
+  rtc::Optional<int> regather_on_failed_networks_interval;
+
+  // The time period in which we will not switch the selected connection
+  // when a new connection becomes receiving but the selected connection is not
+  // in case that the selected connection may become receiving soon.
+  rtc::Optional<int> receiving_switching_delay;
+
+  // TODO(honghaiz): Change the default to regular nomination.
+  // Default nomination mode if the remote does not support renomination.
+  NominationMode default_nomination_mode = NominationMode::SEMI_AGGRESSIVE;
+
+  IceConfig() {}
+  IceConfig(int receiving_timeout_ms,
+            int backup_connection_ping_interval,
+            ContinualGatheringPolicy gathering_policy,
+            bool prioritize_most_likely_candidate_pairs,
+            int stable_writable_connection_ping_interval_ms,
+            bool presume_writable_when_fully_relayed,
+            int regather_on_failed_networks_interval_ms,
+            int receiving_switching_delay_ms)
+      : receiving_timeout(receiving_timeout_ms),
+        backup_connection_ping_interval(backup_connection_ping_interval),
+        continual_gathering_policy(gathering_policy),
+        prioritize_most_likely_candidate_pairs(
+            prioritize_most_likely_candidate_pairs),
+        stable_writable_connection_ping_interval(
+            stable_writable_connection_ping_interval_ms),
+        presume_writable_when_fully_relayed(
+            presume_writable_when_fully_relayed),
+        regather_on_failed_networks_interval(
+            regather_on_failed_networks_interval_ms),
+        receiving_switching_delay(receiving_switching_delay_ms) {}
+};
+
+bool BadTransportDescription(const std::string& desc, std::string* err_desc);
+
+bool IceCredentialsChanged(const std::string& old_ufrag,
+                           const std::string& old_pwd,
+                           const std::string& new_ufrag,
+                           const std::string& new_pwd);
+
+class Transport : public sigslot::has_slots<> {
+ public:
+  Transport(const std::string& name, PortAllocator* allocator);
+  virtual ~Transport();
+
+  // Returns the name of this transport.
+  const std::string& name() const { return name_; }
+
+  // Returns the port allocator object for this transport.
+  PortAllocator* port_allocator() { return allocator_; }
+
+  bool ready_for_remote_candidates() const {
+    return local_description_set_ && remote_description_set_;
+  }
+
+  void SetIceRole(IceRole role);
+  IceRole ice_role() const { return ice_role_; }
+
+  void SetIceTiebreaker(uint64_t IceTiebreaker) { tiebreaker_ = IceTiebreaker; }
+  uint64_t IceTiebreaker() { return tiebreaker_; }
+
+  void SetIceConfig(const IceConfig& config);
+
+  // Must be called before applying local session description.
+  virtual void SetLocalCertificate(
+      const rtc::scoped_refptr<rtc::RTCCertificate>& certificate) {}
+
+  // Get a copy of the local certificate provided by SetLocalCertificate.
+  virtual bool GetLocalCertificate(
+      rtc::scoped_refptr<rtc::RTCCertificate>* certificate) {
+    return false;
+  }
+
+  // Get a copy of the remote certificate in use by the specified channel.
+  std::unique_ptr<rtc::SSLCertificate> GetRemoteSSLCertificate();
+
+  // Create, destroy, and lookup the channels of this type by their components.
+  TransportChannelImpl* CreateChannel(int component);
+
+  TransportChannelImpl* GetChannel(int component);
+
+  bool HasChannel(int component) {
+    return (NULL != GetChannel(component));
+  }
+  bool HasChannels();
+
+  void DestroyChannel(int component);
+
+  // Set the local TransportDescription to be used by TransportChannels.
+  bool SetLocalTransportDescription(const TransportDescription& description,
+                                    ContentAction action,
+                                    std::string* error_desc);
+
+  // Set the remote TransportDescription to be used by TransportChannels.
+  bool SetRemoteTransportDescription(const TransportDescription& description,
+                                     ContentAction action,
+                                     std::string* error_desc);
+
+  // Tells channels to start gathering candidates if necessary.
+  // Should be called after ConnectChannels() has been called at least once,
+  // which will happen in SetLocalTransportDescription.
+  void MaybeStartGathering();
+
+  // Resets all of the channels back to their initial state.  They are no
+  // longer connecting.
+  void ResetChannels();
+
+  // Destroys every channel created so far.
+  void DestroyAllChannels();
+
+  bool GetStats(TransportStats* stats);
+
+  // Called when one or more candidates are ready from the remote peer.
+  bool AddRemoteCandidates(const std::vector<Candidate>& candidates,
+                           std::string* error);
+  bool RemoveRemoteCandidates(const std::vector<Candidate>& candidates,
+                              std::string* error);
+
+  virtual bool GetSslRole(rtc::SSLRole* ssl_role) const { return false; }
+
+  // Must be called before channel is starting to connect.
+  virtual bool SetSslMaxProtocolVersion(rtc::SSLProtocolVersion version) {
+    return false;
+  }
+
+  // The current local transport description, for use by derived classes
+  // when performing transport description negotiation, and possibly used
+  // by the transport controller.
+  const TransportDescription* local_description() const {
+    return local_description_.get();
+  }
+
+  // The current remote transport description, for use by derived classes
+  // when performing transport description negotiation, and possibly used
+  // by the transport controller.
+  const TransportDescription* remote_description() const {
+    return remote_description_.get();
+  }
+
+ protected:
+  // These are called by Create/DestroyChannel above in order to create or
+  // destroy the appropriate type of channel.
+  virtual TransportChannelImpl* CreateTransportChannel(int component) = 0;
+  virtual void DestroyTransportChannel(TransportChannelImpl* channel) = 0;
+
+  // Pushes down the transport parameters from the local description, such
+  // as the ICE ufrag and pwd.
+  // Derived classes can override, but must call the base as well.
+  virtual bool ApplyLocalTransportDescription(TransportChannelImpl* channel,
+                                              std::string* error_desc);
+
+  // Pushes down remote ice credentials from the remote description to the
+  // transport channel.
+  virtual bool ApplyRemoteTransportDescription(TransportChannelImpl* ch,
+                                               std::string* error_desc);
+
+  // Negotiates the transport parameters based on the current local and remote
+  // transport description, such as the ICE role to use, and whether DTLS
+  // should be activated.
+  // Derived classes can negotiate their specific parameters here, but must call
+  // the base as well.
+  virtual bool NegotiateTransportDescription(ContentAction local_role,
+                                             std::string* error_desc);
+
+  // Pushes down the transport parameters obtained via negotiation.
+  // Derived classes can set their specific parameters here, but must call the
+  // base as well.
+  virtual bool ApplyNegotiatedTransportDescription(
+      TransportChannelImpl* channel,
+      std::string* error_desc);
+
+  // Returns false if the certificate's identity does not match the fingerprint,
+  // or either is NULL.
+  virtual bool VerifyCertificateFingerprint(
+      const rtc::RTCCertificate* certificate,
+      const rtc::SSLFingerprint* fingerprint,
+      std::string* error_desc) const;
+
+  // Negotiates the SSL role based off the offer and answer as specified by
+  // RFC 4145, section-4.1. Returns false if the SSL role cannot be determined
+  // from the local description and remote description.
+  virtual bool NegotiateRole(ContentAction local_role,
+                             rtc::SSLRole* ssl_role,
+                             std::string* error_desc) const;
+
+ private:
+  // If a candidate is not acceptable, returns false and sets error.
+  // Call this before calling OnRemoteCandidates.
+  bool VerifyCandidate(const Candidate& candidate, std::string* error);
+  bool VerifyCandidates(const Candidates& candidates, std::string* error);
+
+  // Candidate component => TransportChannelImpl*
+  typedef std::map<int, TransportChannelImpl*> ChannelMap;
+
+  // Helper function that invokes the given function on every channel.
+  typedef void (TransportChannelImpl::* TransportChannelFunc)();
+  void CallChannels(TransportChannelFunc func);
+
+  const std::string name_;
+  PortAllocator* const allocator_;
+  bool channels_destroyed_ = false;
+  IceRole ice_role_ = ICEROLE_UNKNOWN;
+  uint64_t tiebreaker_ = 0;
+  IceMode remote_ice_mode_ = ICEMODE_FULL;
+  IceConfig ice_config_;
+  std::unique_ptr<TransportDescription> local_description_;
+  std::unique_ptr<TransportDescription> remote_description_;
+  bool local_description_set_ = false;
+  bool remote_description_set_ = false;
+
+  ChannelMap channels_;
+
+  RTC_DISALLOW_COPY_AND_ASSIGN(Transport);
+};
+
+
+}  // namespace cricket
+
+#endif  // WEBRTC_P2P_BASE_TRANSPORT_H_