TransportController refactoring

webrtc/p2p/base/faketransportcontroller.h

+/*
+ *  Copyright 2009 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.
+ */

[pthatcher1, 2015/09/01 17:05:21]

Is there something you can do with git to make this look like a file copy/move
rather than a new file?

[Taylor Brandstetter, 2015/09/01 23:53:30]

In my local history that's how it appears. But at some point, the combined
changes must have exceeded some threshold. The only way I can think to fix this
is to submit two separate CLs, one just renaming this file and one with the rest
of the TransportController CL. Unless you know of some git-cl magic...

+
+#ifndef WEBRTC_P2P_BASE_FAKETRANSPORTCONTROLLER_H_
+#define WEBRTC_P2P_BASE_FAKETRANSPORTCONTROLLER_H_
+
+#include <map>
+#include <string>
+#include <vector>
+
+#include "webrtc/p2p/base/transport.h"
+#include "webrtc/p2p/base/transportchannel.h"
+#include "webrtc/p2p/base/transportcontroller.h"
+#include "webrtc/p2p/base/transportchannelimpl.h"
+#include "webrtc/base/bind.h"
+#include "webrtc/base/buffer.h"
+#include "webrtc/base/fakesslidentity.h"
+#include "webrtc/base/messagequeue.h"
+#include "webrtc/base/sigslot.h"
+#include "webrtc/base/sslfingerprint.h"
+#include "webrtc/base/thread.h"
+
+namespace cricket {
+
+class FakeTransport;
+
+struct PacketMessageData : public rtc::MessageData {
+  PacketMessageData(const char* data, size_t len) : packet(data, len) {}
+  rtc::Buffer packet;

[pthatcher1, 2015/09/01 17:05:21]

Can you use TypedMessageData<rtc::Buffer>?

[Taylor Brandstetter, 2015/09/01 23:53:30]

I don't think that would be ideal, since it would involve an extra buffer copy.

+};
+
+// Fake transport channel class, which can be passed to anything that needs a
+// transport channel. Can be informed of another FakeTransportChannel via
+// SetDestination.
+// TODO(hbos): Move implementation to .cc file, this and other classes in file.
+class FakeTransportChannel : public TransportChannelImpl,
+                             public rtc::MessageHandler {
+ public:
+  explicit FakeTransportChannel(Transport* transport,
+                                const std::string& content_name,
+                                int component)
+      : TransportChannelImpl(content_name, component),
+        transport_(transport),
+        dtls_fingerprint_("", nullptr, 0) {}
+  ~FakeTransportChannel() { Reset(); }
+
+  uint64 IceTiebreaker() const { return tiebreaker_; }
+  IceMode remote_ice_mode() const { return remote_ice_mode_; }
+  const std::string& ice_ufrag() const { return ice_ufrag_; }
+  const std::string& ice_pwd() const { return ice_pwd_; }
+  const std::string& remote_ice_ufrag() const { return remote_ice_ufrag_; }
+  const std::string& remote_ice_pwd() const { return remote_ice_pwd_; }
+  const rtc::SSLFingerprint& dtls_fingerprint() const {
+    return dtls_fingerprint_;
+  }
+
+  void SetAsync(bool async) { async_ = async; }
+
+  Transport* GetTransport() override { return transport_; }
+
+  TransportChannelState GetState() const override {
+    if (connection_count_ == 0) {
+      return had_connection_ ? TransportChannelState::STATE_FAILED
+                             : TransportChannelState::STATE_INIT;
+    }
+
+    if (connection_count_ == 1) {
+      return TransportChannelState::STATE_COMPLETED;
+    }
+
+    return TransportChannelState::STATE_CONNECTING;
+  }
+
+  void SetIceRole(IceRole role) override { role_ = role; }
+  IceRole GetIceRole() const override { return role_; }
+  void SetIceTiebreaker(uint64 tiebreaker) override {
+    tiebreaker_ = tiebreaker;
+  }
+  void SetIceCredentials(const std::string& ice_ufrag,
+                         const std::string& ice_pwd) override {
+    ice_ufrag_ = ice_ufrag;
+    ice_pwd_ = ice_pwd;
+  }
+  void SetRemoteIceCredentials(const std::string& ice_ufrag,
+                               const std::string& ice_pwd) override {
+    remote_ice_ufrag_ = ice_ufrag;
+    remote_ice_pwd_ = ice_pwd;
+  }
+
+  void SetRemoteIceMode(IceMode mode) override { remote_ice_mode_ = mode; }
+  bool SetRemoteFingerprint(const std::string& alg,
+                            const uint8* digest,
+                            size_t digest_len) override {
+    dtls_fingerprint_ = rtc::SSLFingerprint(alg, digest, digest_len);
+    return true;
+  }
+  bool SetSslRole(rtc::SSLRole role) override {
+    ssl_role_ = role;
+    return true;
+  }
+  bool GetSslRole(rtc::SSLRole* role) const override {
+    *role = ssl_role_;
+    return true;
+  }
+
+  void Connect() override {
+    if (state_ == STATE_INIT) {
+      state_ = STATE_CONNECTING;
+      // Connect is expected to start candidate gathering
+      if (gathering_state_ != kIceGatheringGathering) {
+        gathering_state_ = kIceGatheringGathering;
+        SignalGatheringState(this);
+      }
+    }
+  }
+
+  IceGatheringState gathering_state() const override {
+    return gathering_state_;
+  }
+
+  void Reset() {
+    if (state_ != STATE_INIT) {
+      state_ = STATE_INIT;
+      if (dest_) {
+        dest_->state_ = STATE_INIT;
+        dest_->dest_ = nullptr;
+        dest_ = nullptr;
+      }
+    }
+  }
+
+  void SetWritable(bool writable) { set_writable(writable); }
+
+  void SetDestination(FakeTransportChannel* dest) {
+    if (state_ == STATE_CONNECTING && dest) {
+      // This simulates the delivery of candidates.
+      dest_ = dest;
+      dest_->dest_ = this;
+      if (identity_ && dest_->identity_) {
+        do_dtls_ = true;
+        dest_->do_dtls_ = true;
+        NegotiateSrtpCiphers();
+      }
+      state_ = STATE_CONNECTED;
+      dest_->state_ = STATE_CONNECTED;
+      set_writable(true);
+      dest_->set_writable(true);
+    } else if (state_ == STATE_CONNECTED && !dest) {
+      // Simulates loss of connectivity, by asymmetrically forgetting dest_.
+      dest_ = nullptr;
+      state_ = STATE_CONNECTING;
+      set_writable(false);
+    }
+  }
+
+  void SetConnectionCount(size_t connection_count) {
+    size_t old_connection_count = connection_count_;
+    connection_count_ = connection_count;
+    if (connection_count)
+      had_connection_ = true;
+    if (connection_count_ < old_connection_count)
+      SignalConnectionRemoved(this);
+  }
+
+  void SetCandidatesGatheringComplete() {
+    if (gathering_state_ != kIceGatheringComplete) {
+      gathering_state_ = kIceGatheringComplete;
+      SignalGatheringState(this);
+    }
+  }
+
+  void SetReceiving(bool receiving) { set_receiving(receiving); }
+
+  void SetReceivingTimeout(int timeout) override {
+    receiving_timeout_ = timeout;
+  }
+
+  int receiving_timeout() const { return receiving_timeout_; }
+
+  int SendPacket(const char* data,
+                 size_t len,
+                 const rtc::PacketOptions& options,
+                 int flags) override {
+    if (state_ != STATE_CONNECTED) {
+      return -1;
+    }
+
+    if (flags != PF_SRTP_BYPASS && flags != 0) {
+      return -1;
+    }
+
+    PacketMessageData* packet = new PacketMessageData(data, len);
+    if (async_) {
+      rtc::Thread::Current()->Post(this, 0, packet);
+    } else {
+      rtc::Thread::Current()->Send(this, 0, packet);
+    }
+    return static_cast<int>(len);
+  }
+  int SetOption(rtc::Socket::Option opt, int value) override { return true; }
+  bool GetOption(rtc::Socket::Option opt, int* value) override { return true; }
+  int GetError() override { return 0; }
+
+  void AddRemoteCandidate(const Candidate& candidate) override {
+    remote_candidates_.push_back(candidate);
+  }
+  const Candidates& remote_candidates() const { return remote_candidates_; }
+
+  void OnMessage(rtc::Message* msg) override {
+    PacketMessageData* data = static_cast<PacketMessageData*>(msg->pdata);
+    dest_->SignalReadPacket(dest_, data->packet.data<char>(),
+                            data->packet.size(), rtc::CreatePacketTime(0), 0);
+    delete data;
+  }
+
+  bool SetLocalIdentity(rtc::SSLIdentity* identity) {
+    identity_ = identity;
+    return true;
+  }
+
+  void SetRemoteCertificate(rtc::FakeSSLCertificate* cert) {
+    remote_cert_ = cert;
+  }
+
+  bool IsDtlsActive() const override { return do_dtls_; }
+
+  bool SetSrtpCiphers(const std::vector<std::string>& ciphers) override {
+    srtp_ciphers_ = ciphers;
+    return true;
+  }
+
+  bool GetSrtpCipher(std::string* cipher) override {
+    if (!chosen_srtp_cipher_.empty()) {
+      *cipher = chosen_srtp_cipher_;
+      return true;
+    }
+    return false;
+  }
+
+  bool GetSslCipher(std::string* cipher) override { return false; }
+
+  bool GetLocalIdentity(rtc::SSLIdentity** identity) const override {
+    if (!identity_)
+      return false;
+
+    *identity = identity_->GetReference();
+    return true;
+  }
+
+  bool GetRemoteCertificate(rtc::SSLCertificate** cert) const override {
+    if (!remote_cert_)
+      return false;
+
+    *cert = remote_cert_->GetReference();
+    return true;
+  }
+
+  bool ExportKeyingMaterial(const std::string& label,
+                            const uint8* context,
+                            size_t context_len,
+                            bool use_context,
+                            uint8* result,
+                            size_t result_len) override {
+    if (!chosen_srtp_cipher_.empty()) {
+      memset(result, 0xff, result_len);
+      return true;
+    }
+
+    return false;
+  }
+
+  void NegotiateSrtpCiphers() {
+    for (std::vector<std::string>::const_iterator it1 = srtp_ciphers_.begin();
+         it1 != srtp_ciphers_.end(); ++it1) {
+      for (std::vector<std::string>::const_iterator it2 =
+               dest_->srtp_ciphers_.begin();
+           it2 != dest_->srtp_ciphers_.end(); ++it2) {
+        if (*it1 == *it2) {
+          chosen_srtp_cipher_ = *it1;
+          dest_->chosen_srtp_cipher_ = *it2;
+          return;
+        }
+      }
+    }
+  }
+
+  bool GetStats(ConnectionInfos* infos) override {
+    ConnectionInfo info;
+    infos->clear();
+    infos->push_back(info);
+    return true;
+  }
+
+  void set_ssl_max_protocol_version(rtc::SSLProtocolVersion version) {
+    ssl_max_version_ = version;
+  }
+  rtc::SSLProtocolVersion ssl_max_protocol_version() const {
+    return ssl_max_version_;
+  }
+
+ private:
+  enum State { STATE_INIT, STATE_CONNECTING, STATE_CONNECTED };
+  Transport* transport_;
+  FakeTransportChannel* dest_ = nullptr;
+  State state_ = STATE_INIT;
+  bool async_ = false;
+  Candidates remote_candidates_;
+  rtc::SSLIdentity* identity_ = nullptr;
+  rtc::FakeSSLCertificate* remote_cert_ = nullptr;
+  bool do_dtls_ = false;
+  std::vector<std::string> srtp_ciphers_;
+  std::string chosen_srtp_cipher_;
+  int receiving_timeout_ = -1;
+  IceRole role_ = ICEROLE_UNKNOWN;
+  uint64 tiebreaker_ = 0;
+  std::string ice_ufrag_;
+  std::string ice_pwd_;
+  std::string remote_ice_ufrag_;
+  std::string remote_ice_pwd_;
+  IceMode remote_ice_mode_ = ICEMODE_FULL;
+  rtc::SSLProtocolVersion ssl_max_version_ = rtc::SSL_PROTOCOL_DTLS_10;
+  rtc::SSLFingerprint dtls_fingerprint_;
+  rtc::SSLRole ssl_role_ = rtc::SSL_CLIENT;
+  size_t connection_count_ = 0;
+  IceGatheringState gathering_state_ = kIceGatheringNew;
+  bool had_connection_ = false;
+};
+
+// Fake transport class, which can be passed to anything that needs a Transport.
+// Can be informed of another FakeTransport via SetDestination (low-tech way
+// of doing candidates)
+class FakeTransport : public Transport {
+ public:
+  typedef std::map<int, FakeTransportChannel*> ChannelMap;
+  // Note that the constructor only needs the allocator parameter so it can be
+  // wrapped by a DtlsTransport
+  FakeTransport(const std::string& content_name,
+                PortAllocator* allocator = nullptr)

[pthatcher1, 2015/09/01 17:05:21]

We usually prefer separate methods/constructors rather than use default
variables.  

[Taylor Brandstetter, 2015/09/01 23:53:30]

Done.

+      : Transport(content_name, nullptr) {}
+
+  ~FakeTransport() { DestroyAllChannels(); }
+
+  const ChannelMap& channels() const { return channels_; }
+
+  void SetAsync(bool async) { async_ = async; }

[pthatcher1, 2015/09/01 17:05:21]

Can you comment what this does?

[Taylor Brandstetter, 2015/09/01 23:53:30]

Done.

+  void SetDestination(FakeTransport* dest) {
+    dest_ = dest;
+    for (const auto& kv : channels_) {
+      // TODO(hbos): SetLocalCertificate
+      kv.second->SetLocalIdentity(certificate_ ? certificate_->identity()
+                                               : nullptr);
+      SetChannelDestination(kv.first, kv.second);
+    }
+  }
+
+  void SetWritable(bool writable) {
+    for (const auto& kv : channels_) {
+      kv.second->SetWritable(writable);
+    }
+  }
+
+  void SetCertificate(
+      const rtc::scoped_refptr<rtc::RTCCertificate>& certificate) override {
+    certificate_ = certificate;
+  }
+  bool GetCertificate(
+      rtc::scoped_refptr<rtc::RTCCertificate>* certificate) override {
+    if (!certificate_)
+      return false;
+
+    *certificate = certificate_;
+    return true;
+  }
+
+  bool GetSslRole(rtc::SSLRole* role) const override {
+    if (channels_.empty()) {
+      return false;
+    }
+    return channels_.cbegin()->second->GetSslRole(role);
+  }
+
+  bool SetSslMaxProtocolVersion(rtc::SSLProtocolVersion version) override {
+    ssl_max_version_ = version;
+    for (const auto& kv : channels_) {
+      kv.second->set_ssl_max_protocol_version(ssl_max_version_);
+    }
+    return true;
+  }
+  rtc::SSLProtocolVersion ssl_max_protocol_version() const {
+    return ssl_max_version_;
+  }
+
+  using Transport::local_description;
+  using Transport::remote_description;
+
+ protected:
+  TransportChannelImpl* CreateTransportChannel(int component) override {
+    if (channels_.find(component) != channels_.end()) {
+      return nullptr;
+    }
+    FakeTransportChannel* channel =
+        new FakeTransportChannel(this, content_name(), component);
+    channel->set_ssl_max_protocol_version(ssl_max_version_);
+    channel->SetAsync(async_);
+    SetChannelDestination(component, channel);
+    channels_[component] = channel;
+    return channel;
+  }
+
+  void DestroyTransportChannel(TransportChannelImpl* channel) override {
+    channels_.erase(channel->component());
+    delete channel;
+  }
+
+ private:
+  FakeTransportChannel* GetFakeChannel(int component) {
+    auto it = channels_.find(component);
+    return (it != channels_.end()) ? it->second : nullptr;
+  }
+
+  void SetChannelDestination(int component, FakeTransportChannel* channel) {
+    FakeTransportChannel* dest_channel = nullptr;
+    if (dest_) {
+      dest_channel = dest_->GetFakeChannel(component);
+      if (dest_channel) {
+        // TODO(hbos): SetLocalCertificate
+        dest_channel->SetLocalIdentity(
+            dest_->certificate_ ? dest_->certificate_->identity() : nullptr);
+      }
+    }
+    channel->SetDestination(dest_channel);
+  }
+
+  // Note, this is distinct from the Channel map owned by Transport.
+  // This map just tracks the FakeTransportChannels created by this class.
+  // It's mainly needed so that we can access a FakeTransportChannel directly,
+  // even if wrapped by a DtlsTransportChannelWrapper.
+  ChannelMap channels_;
+  FakeTransport* dest_ = nullptr;
+  bool async_ = false;
+  rtc::scoped_refptr<rtc::RTCCertificate> certificate_;
+  rtc::SSLProtocolVersion ssl_max_version_ = rtc::SSL_PROTOCOL_DTLS_10;
+};
+
+// Fake TransportController class, which can be passed into a BaseChannel object
+// for test purposes. Can be connected to other FakeTransportControllers via
+// Connect().

[pthatcher1, 2015/09/01 17:05:21]

This isn't really a FakeTransportController.  It's a real TransportController
with some extra stuff for testing, and with fake TransportChannels.

I think TransportContollerForTest might be a better name, at least for the
TransportController unit tests (where it's really confusing that you make a fake
object to test a real one).

I'd normally suggest you just put this in transportcontroller_unittest.cc, but
if you also need it in channel_unittest.cc, and perhaps other tests, then you'll
need it in a shared place.


So here's my idea:
1.  Leave this here as FakeTransportController, with a comment saying something
like "This fake is unusual in that it's implemented with the real
TransportController code, but with fake TransportChannels underneath".

2.  Subclass FakeTransportController in transportcontroller_unittest.cc as
TransportControllerForTest with a comment like "The FakeTransportController
isn't really a full fake; It just fakes the transport controller", but then use
TransportControllerForTest throughout the rest of the file, to make that code
more clear/readable.

3.  Move any logic that is only needed by transportcontroller_unittest.cc but
not needed by other things into TransportControllerForTest and out of
FakeTransportController.  


Does that make sense?

[Taylor Brandstetter, 2015/09/01 23:53:30]

This is part of why I had that conversation with you about how
TransportController and Transport should just take a TransportChannelFactory,
and then work the same way regardless of whether they have a real or fake
transport channel. But if I recall correctly, we decided to hold off on that
until we made the separation between an IceTransport and DtlsTransport.

In the meantime, I'll follow your suggestions. Though there's nothing to be done
for #3, so I'll just leave it as a typedef.

+class FakeTransportController : public TransportController {
+ public:
+  FakeTransportController()
+      : TransportController(rtc::Thread::Current(),
+                            rtc::Thread::Current(),
+                            nullptr),
+        fail_create_channel_(false) {}
+
+  explicit FakeTransportController(bool initiator)
+      : TransportController(rtc::Thread::Current(),
+                            rtc::Thread::Current(),
+                            nullptr),
+        fail_create_channel_(false) {
+    SetIceRole(initiator ? ICEROLE_CONTROLLING : ICEROLE_CONTROLLED);
+  }

[pthatcher1, 2015/09/01 17:05:21]

Can we just pass in the IceRole instead of the initiator boolean?  

[Taylor Brandstetter, 2015/09/01 23:53:30]

Done.

+
+  explicit FakeTransportController(rtc::Thread* worker_thread)
+      : TransportController(rtc::Thread::Current(), worker_thread, nullptr),
+        fail_create_channel_(false) {
+  }
+
+  FakeTransportController(rtc::Thread* worker_thread, bool initiator)
+      : TransportController(rtc::Thread::Current(), worker_thread, nullptr),
+        fail_create_channel_(false) {
+    SetIceRole(initiator ? ICEROLE_CONTROLLING : ICEROLE_CONTROLLED);
+  }
+
+  FakeTransport* GetTransport_w(const std::string& transport_name) {
+    return static_cast<FakeTransport*>(
+        TransportController::GetTransport_w(transport_name));
+  }
+
+  void Connect(FakeTransportController* dest) {
+    worker_thread()->Invoke<void>(
+        rtc::Bind(&FakeTransportController::Connect_w, this, dest));
+  }
+
+  TransportChannel* CreateTransportChannel_w(const std::string& transport_name,
+                                             int component) override {
+    if (fail_create_channel_) {
+      return nullptr;
+    }
+    return TransportController::CreateTransportChannel_w(transport_name,
+                                                         component);
+  }
+
+  void set_fail_channel_creation(bool fail_channel_creation) {
+    fail_create_channel_ = fail_channel_creation;
+  }
+
+ protected:
+  Transport* CreateTransport_w(const std::string& transport_name) override {
+    return new FakeTransport(transport_name);
+  }
+
+  void Connect_w(FakeTransportController* dest) {
+    // Simulate the exchange of candidates.
+    ConnectChannels_w();
+    dest->ConnectChannels_w();
+    for (auto& kv : transports()) {
+      FakeTransport* transport = static_cast<FakeTransport*>(kv.second);
+      transport->SetDestination(dest->GetTransport_w(kv.first));
+    }
+  }
+
+  void ConnectChannels_w() {
+    for (auto& kv : transports()) {
+      FakeTransport* transport = static_cast<FakeTransport*>(kv.second);
+      transport->ConnectChannels();
+    }
+  }
+
+ private:
+  bool fail_create_channel_;
+};
+
+}  // namespace cricket
+
+#endif  // WEBRTC_P2P_BASE_FAKETRANSPORTCONTROLLER_H_