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1 /*
2  *  Copyright 2017 The WebRTC Project Authors. All rights reserved.
3  *
4  *  Use of this source code is governed by a BSD-style license
5  *  that can be found in the LICENSE file in the root of the source
6  *  tree. An additional intellectual property rights grant can be found
7  *  in the file PATENTS.  All contributing project authors may
8  *  be found in the AUTHORS file in the root of the source tree.
9  */
10 
11 #ifndef PC_JSEP_TRANSPORT_CONTROLLER_H_
12 #define PC_JSEP_TRANSPORT_CONTROLLER_H_
13 
14 #include <stdint.h>
15 
16 #include <functional>
17 #include <map>
18 #include <memory>
19 #include <string>
20 #include <type_traits>
21 #include <utility>
22 #include <vector>
23 
24 #include "absl/types/optional.h"
25 #include "api/async_dns_resolver.h"
26 #include "api/candidate.h"
27 #include "api/crypto/crypto_options.h"
28 #include "api/ice_transport_factory.h"
29 #include "api/ice_transport_interface.h"
30 #include "api/jsep.h"
31 #include "api/peer_connection_interface.h"
32 #include "api/rtc_error.h"
33 #include "api/rtc_event_log/rtc_event_log.h"
34 #include "api/scoped_refptr.h"
35 #include "api/sequence_checker.h"
36 #include "api/transport/data_channel_transport_interface.h"
37 #include "api/transport/sctp_transport_factory_interface.h"
38 #include "media/sctp/sctp_transport_internal.h"
39 #include "p2p/base/dtls_transport.h"
40 #include "p2p/base/dtls_transport_factory.h"
41 #include "p2p/base/dtls_transport_internal.h"
42 #include "p2p/base/ice_transport_internal.h"
43 #include "p2p/base/p2p_transport_channel.h"
44 #include "p2p/base/packet_transport_internal.h"
45 #include "p2p/base/port.h"
46 #include "p2p/base/port_allocator.h"
47 #include "p2p/base/transport_description.h"
48 #include "p2p/base/transport_info.h"
49 #include "pc/dtls_srtp_transport.h"
50 #include "pc/dtls_transport.h"
51 #include "pc/jsep_transport.h"
52 #include "pc/jsep_transport_collection.h"
53 #include "pc/rtp_transport.h"
54 #include "pc/rtp_transport_internal.h"
55 #include "pc/sctp_transport.h"
56 #include "pc/session_description.h"
57 #include "pc/srtp_transport.h"
58 #include "pc/transport_stats.h"
59 #include "rtc_base/callback_list.h"
60 #include "rtc_base/checks.h"
61 #include "rtc_base/copy_on_write_buffer.h"
62 #include "rtc_base/helpers.h"
63 #include "rtc_base/rtc_certificate.h"
64 #include "rtc_base/ssl_certificate.h"
65 #include "rtc_base/ssl_stream_adapter.h"
66 #include "rtc_base/third_party/sigslot/sigslot.h"
67 #include "rtc_base/thread.h"
68 #include "rtc_base/thread_annotations.h"
69 
70 namespace rtc {
71 class Thread;
72 class PacketTransportInternal;
73 }  // namespace rtc
74 
75 namespace webrtc {
76 
77 class JsepTransportController : public sigslot::has_slots<> {
78  public:
79   // Used when the RtpTransport/DtlsTransport of the m= section is changed
80   // because the section is rejected or BUNDLE is enabled.
81   class Observer {
82    public:
~Observer()83     virtual ~Observer() {}
84 
85     // Returns true if media associated with `mid` was successfully set up to be
86     // demultiplexed on `rtp_transport`. Could return false if two bundled m=
87     // sections use the same SSRC, for example.
88     //
89     // If a data channel transport must be negotiated, `data_channel_transport`
90     // and `negotiation_state` indicate negotiation status.  If
91     // `data_channel_transport` is null, the data channel transport should not
92     // be used.  Otherwise, the value is a pointer to the transport to be used
93     // for data channels on `mid`, if any.
94     //
95     // The observer should not send data on `data_channel_transport` until
96     // `negotiation_state` is provisional or final.  It should not delete
97     // `data_channel_transport` or any fallback transport until
98     // `negotiation_state` is final.
99     virtual bool OnTransportChanged(
100         const std::string& mid,
101         RtpTransportInternal* rtp_transport,
102         rtc::scoped_refptr<DtlsTransport> dtls_transport,
103         DataChannelTransportInterface* data_channel_transport) = 0;
104   };
105 
106   struct Config {
107     // If `redetermine_role_on_ice_restart` is true, ICE role is redetermined
108     // upon setting a local transport description that indicates an ICE
109     // restart.
110     bool redetermine_role_on_ice_restart = true;
111     rtc::SSLProtocolVersion ssl_max_version = rtc::SSL_PROTOCOL_DTLS_12;
112     // `crypto_options` is used to determine if created DTLS transports
113     // negotiate GCM crypto suites or not.
114     webrtc::CryptoOptions crypto_options;
115     PeerConnectionInterface::BundlePolicy bundle_policy =
116         PeerConnectionInterface::kBundlePolicyBalanced;
117     PeerConnectionInterface::RtcpMuxPolicy rtcp_mux_policy =
118         PeerConnectionInterface::kRtcpMuxPolicyRequire;
119     bool disable_encryption = false;
120     bool enable_external_auth = false;
121     // Used to inject the ICE/DTLS transports created externally.
122     webrtc::IceTransportFactory* ice_transport_factory = nullptr;
123     cricket::DtlsTransportFactory* dtls_transport_factory = nullptr;
124     Observer* transport_observer = nullptr;
125     // Must be provided and valid for the lifetime of the
126     // JsepTransportController instance.
127     std::function<void(const rtc::CopyOnWriteBuffer& packet,
128                        int64_t packet_time_us)>
129         rtcp_handler;
130     // Initial value for whether DtlsTransport reset causes a reset
131     // of SRTP parameters.
132     bool active_reset_srtp_params = false;
133     RtcEventLog* event_log = nullptr;
134 
135     // Factory for SCTP transports.
136     SctpTransportFactoryInterface* sctp_factory = nullptr;
137     std::function<void(rtc::SSLHandshakeError)> on_dtls_handshake_error_;
138 
139     // Field trials.
140     const webrtc::FieldTrialsView* field_trials;
141   };
142 
143   // The ICE related events are fired on the `network_thread`.
144   // All the transport related methods are called on the `network_thread`
145   // and destruction of the JsepTransportController must occur on the
146   // `network_thread`.
147   JsepTransportController(
148       rtc::Thread* network_thread,
149       cricket::PortAllocator* port_allocator,
150       AsyncDnsResolverFactoryInterface* async_dns_resolver_factory,
151       Config config);
152   virtual ~JsepTransportController();
153 
154   JsepTransportController(const JsepTransportController&) = delete;
155   JsepTransportController& operator=(const JsepTransportController&) = delete;
156 
157   // The main method to be called; applies a description at the transport
158   // level, creating/destroying transport objects as needed and updating their
159   // properties. This includes RTP, DTLS, and ICE (but not SCTP). At least not
160   // yet? May make sense to in the future.
161   RTCError SetLocalDescription(SdpType type,
162                                const cricket::SessionDescription* description);
163 
164   RTCError SetRemoteDescription(SdpType type,
165                                 const cricket::SessionDescription* description);
166 
167   // Get transports to be used for the provided `mid`. If bundling is enabled,
168   // calling GetRtpTransport for multiple MIDs may yield the same object.
169   RtpTransportInternal* GetRtpTransport(absl::string_view mid) const;
170   cricket::DtlsTransportInternal* GetDtlsTransport(const std::string& mid);
171   const cricket::DtlsTransportInternal* GetRtcpDtlsTransport(
172       const std::string& mid) const;
173   // Gets the externally sharable version of the DtlsTransport.
174   rtc::scoped_refptr<webrtc::DtlsTransport> LookupDtlsTransportByMid(
175       const std::string& mid);
176   rtc::scoped_refptr<SctpTransport> GetSctpTransport(
177       const std::string& mid) const;
178 
179   DataChannelTransportInterface* GetDataChannelTransport(
180       const std::string& mid) const;
181 
182   /*********************
183    * ICE-related methods
184    ********************/
185   // This method is public to allow PeerConnection to update it from
186   // SetConfiguration.
187   void SetIceConfig(const cricket::IceConfig& config);
188   // Set the "needs-ice-restart" flag as described in JSEP. After the flag is
189   // set, offers should generate new ufrags/passwords until an ICE restart
190   // occurs.
191   void SetNeedsIceRestartFlag();
192   // Returns true if the ICE restart flag above was set, and no ICE restart has
193   // occurred yet for this transport (by applying a local description with
194   // changed ufrag/password). If the transport has been deleted as a result of
195   // bundling, returns false.
196   bool NeedsIceRestart(const std::string& mid) const;
197   // Start gathering candidates for any new transports, or transports doing an
198   // ICE restart.
199   void MaybeStartGathering();
200   RTCError AddRemoteCandidates(
201       const std::string& mid,
202       const std::vector<cricket::Candidate>& candidates);
203   RTCError RemoveRemoteCandidates(
204       const std::vector<cricket::Candidate>& candidates);
205 
206   /**********************
207    * DTLS-related methods
208    *********************/
209   // Specifies the identity to use in this session.
210   // Can only be called once.
211   bool SetLocalCertificate(
212       const rtc::scoped_refptr<rtc::RTCCertificate>& certificate);
213   rtc::scoped_refptr<rtc::RTCCertificate> GetLocalCertificate(
214       const std::string& mid) const;
215   // Caller owns returned certificate chain. This method mainly exists for
216   // stats reporting.
217   std::unique_ptr<rtc::SSLCertChain> GetRemoteSSLCertChain(
218       const std::string& mid) const;
219   // Get negotiated role, if one has been negotiated.
220   absl::optional<rtc::SSLRole> GetDtlsRole(const std::string& mid) const;
221 
222   // TODO(deadbeef): GetStats isn't const because all the way down to
223   // OpenSSLStreamAdapter, GetSslCipherSuite and GetDtlsSrtpCryptoSuite are not
224   // const. Fix this.
225   bool GetStats(const std::string& mid, cricket::TransportStats* stats);
226 
initial_offerer()227   bool initial_offerer() const { return initial_offerer_ && *initial_offerer_; }
228 
229   void SetActiveResetSrtpParams(bool active_reset_srtp_params);
230 
231   RTCError RollbackTransports();
232 
233   // F: void(const std::string&, const std::vector<cricket::Candidate>&)
234   template <typename F>
SubscribeIceCandidateGathered(F && callback)235   void SubscribeIceCandidateGathered(F&& callback) {
236     RTC_DCHECK_RUN_ON(network_thread_);
237     signal_ice_candidates_gathered_.AddReceiver(std::forward<F>(callback));
238   }
239 
240   // F: void(cricket::IceConnectionState)
241   template <typename F>
SubscribeIceConnectionState(F && callback)242   void SubscribeIceConnectionState(F&& callback) {
243     RTC_DCHECK_RUN_ON(network_thread_);
244     signal_ice_connection_state_.AddReceiver(std::forward<F>(callback));
245   }
246 
247   // F: void(PeerConnectionInterface::PeerConnectionState)
248   template <typename F>
SubscribeConnectionState(F && callback)249   void SubscribeConnectionState(F&& callback) {
250     RTC_DCHECK_RUN_ON(network_thread_);
251     signal_connection_state_.AddReceiver(std::forward<F>(callback));
252   }
253 
254   // F: void(PeerConnectionInterface::IceConnectionState)
255   template <typename F>
SubscribeStandardizedIceConnectionState(F && callback)256   void SubscribeStandardizedIceConnectionState(F&& callback) {
257     RTC_DCHECK_RUN_ON(network_thread_);
258     signal_standardized_ice_connection_state_.AddReceiver(
259         std::forward<F>(callback));
260   }
261 
262   // F: void(cricket::IceGatheringState)
263   template <typename F>
SubscribeIceGatheringState(F && callback)264   void SubscribeIceGatheringState(F&& callback) {
265     RTC_DCHECK_RUN_ON(network_thread_);
266     signal_ice_gathering_state_.AddReceiver(std::forward<F>(callback));
267   }
268 
269   // F: void(const cricket::IceCandidateErrorEvent&)
270   template <typename F>
SubscribeIceCandidateError(F && callback)271   void SubscribeIceCandidateError(F&& callback) {
272     RTC_DCHECK_RUN_ON(network_thread_);
273     signal_ice_candidate_error_.AddReceiver(std::forward<F>(callback));
274   }
275 
276   // F: void(const std::vector<cricket::Candidate>&)
277   template <typename F>
SubscribeIceCandidatesRemoved(F && callback)278   void SubscribeIceCandidatesRemoved(F&& callback) {
279     RTC_DCHECK_RUN_ON(network_thread_);
280     signal_ice_candidates_removed_.AddReceiver(std::forward<F>(callback));
281   }
282 
283   // F: void(const cricket::CandidatePairChangeEvent&)
284   template <typename F>
SubscribeIceCandidatePairChanged(F && callback)285   void SubscribeIceCandidatePairChanged(F&& callback) {
286     RTC_DCHECK_RUN_ON(network_thread_);
287     signal_ice_candidate_pair_changed_.AddReceiver(std::forward<F>(callback));
288   }
289 
290  private:
291   // All of these callbacks are fired on the network thread.
292 
293   // If any transport failed => failed,
294   // Else if all completed => completed,
295   // Else if all connected => connected,
296   // Else => connecting
297   CallbackList<cricket::IceConnectionState> signal_ice_connection_state_
298       RTC_GUARDED_BY(network_thread_);
299 
300   CallbackList<PeerConnectionInterface::PeerConnectionState>
301       signal_connection_state_ RTC_GUARDED_BY(network_thread_);
302 
303   CallbackList<PeerConnectionInterface::IceConnectionState>
304       signal_standardized_ice_connection_state_ RTC_GUARDED_BY(network_thread_);
305 
306   // If all transports done gathering => complete,
307   // Else if any are gathering => gathering,
308   // Else => new
309   CallbackList<cricket::IceGatheringState> signal_ice_gathering_state_
310       RTC_GUARDED_BY(network_thread_);
311 
312   // [mid, candidates]
313   CallbackList<const std::string&, const std::vector<cricket::Candidate>&>
314       signal_ice_candidates_gathered_ RTC_GUARDED_BY(network_thread_);
315 
316   CallbackList<const cricket::IceCandidateErrorEvent&>
317       signal_ice_candidate_error_ RTC_GUARDED_BY(network_thread_);
318 
319   CallbackList<const std::vector<cricket::Candidate>&>
320       signal_ice_candidates_removed_ RTC_GUARDED_BY(network_thread_);
321 
322   CallbackList<const cricket::CandidatePairChangeEvent&>
323       signal_ice_candidate_pair_changed_ RTC_GUARDED_BY(network_thread_);
324 
325   RTCError ApplyDescription_n(bool local,
326                               SdpType type,
327                               const cricket::SessionDescription* description)
328       RTC_RUN_ON(network_thread_);
329   RTCError ValidateAndMaybeUpdateBundleGroups(
330       bool local,
331       SdpType type,
332       const cricket::SessionDescription* description);
333   RTCError ValidateContent(const cricket::ContentInfo& content_info);
334 
335   void HandleRejectedContent(const cricket::ContentInfo& content_info)
336       RTC_RUN_ON(network_thread_);
337   bool HandleBundledContent(const cricket::ContentInfo& content_info,
338                             const cricket::ContentGroup& bundle_group)
339       RTC_RUN_ON(network_thread_);
340 
341   cricket::JsepTransportDescription CreateJsepTransportDescription(
342       const cricket::ContentInfo& content_info,
343       const cricket::TransportInfo& transport_info,
344       const std::vector<int>& encrypted_extension_ids,
345       int rtp_abs_sendtime_extn_id);
346 
347   std::map<const cricket::ContentGroup*, std::vector<int>>
348   MergeEncryptedHeaderExtensionIdsForBundles(
349       const cricket::SessionDescription* description);
350   std::vector<int> GetEncryptedHeaderExtensionIds(
351       const cricket::ContentInfo& content_info);
352 
353   int GetRtpAbsSendTimeHeaderExtensionId(
354       const cricket::ContentInfo& content_info);
355 
356   // This method takes the BUNDLE group into account. If the JsepTransport is
357   // destroyed because of BUNDLE, it would return the transport which other
358   // transports are bundled on (In current implementation, it is the first
359   // content in the BUNDLE group).
360   const cricket::JsepTransport* GetJsepTransportForMid(
361       const std::string& mid) const RTC_RUN_ON(network_thread_);
362   cricket::JsepTransport* GetJsepTransportForMid(const std::string& mid)
363       RTC_RUN_ON(network_thread_);
364   const cricket::JsepTransport* GetJsepTransportForMid(
365       absl::string_view mid) const RTC_RUN_ON(network_thread_);
366   cricket::JsepTransport* GetJsepTransportForMid(absl::string_view mid)
367       RTC_RUN_ON(network_thread_);
368 
369   // Get the JsepTransport without considering the BUNDLE group. Return nullptr
370   // if the JsepTransport is destroyed.
371   const cricket::JsepTransport* GetJsepTransportByName(
372       const std::string& transport_name) const RTC_RUN_ON(network_thread_);
373   cricket::JsepTransport* GetJsepTransportByName(
374       const std::string& transport_name) RTC_RUN_ON(network_thread_);
375 
376   // Creates jsep transport. Noop if transport is already created.
377   // Transport is created either during SetLocalDescription (`local` == true) or
378   // during SetRemoteDescription (`local` == false). Passing `local` helps to
379   // differentiate initiator (caller) from answerer (callee).
380   RTCError MaybeCreateJsepTransport(
381       bool local,
382       const cricket::ContentInfo& content_info,
383       const cricket::SessionDescription& description)
384       RTC_RUN_ON(network_thread_);
385 
386   void DestroyAllJsepTransports_n() RTC_RUN_ON(network_thread_);
387 
388   void SetIceRole_n(cricket::IceRole ice_role) RTC_RUN_ON(network_thread_);
389 
390   cricket::IceRole DetermineIceRole(
391       cricket::JsepTransport* jsep_transport,
392       const cricket::TransportInfo& transport_info,
393       SdpType type,
394       bool local);
395 
396   std::unique_ptr<cricket::DtlsTransportInternal> CreateDtlsTransport(
397       const cricket::ContentInfo& content_info,
398       cricket::IceTransportInternal* ice);
399   rtc::scoped_refptr<webrtc::IceTransportInterface> CreateIceTransport(
400       const std::string& transport_name,
401       bool rtcp);
402 
403   std::unique_ptr<webrtc::RtpTransport> CreateUnencryptedRtpTransport(
404       const std::string& transport_name,
405       rtc::PacketTransportInternal* rtp_packet_transport,
406       rtc::PacketTransportInternal* rtcp_packet_transport);
407   std::unique_ptr<webrtc::SrtpTransport> CreateSdesTransport(
408       const std::string& transport_name,
409       cricket::DtlsTransportInternal* rtp_dtls_transport,
410       cricket::DtlsTransportInternal* rtcp_dtls_transport);
411   std::unique_ptr<webrtc::DtlsSrtpTransport> CreateDtlsSrtpTransport(
412       const std::string& transport_name,
413       cricket::DtlsTransportInternal* rtp_dtls_transport,
414       cricket::DtlsTransportInternal* rtcp_dtls_transport);
415 
416   // Collect all the DtlsTransports, including RTP and RTCP, from the
417   // JsepTransports, including those not mapped to a MID because they are being
418   // kept alive in case of rollback.
419   std::vector<cricket::DtlsTransportInternal*> GetDtlsTransports();
420   // Same as the above, but doesn't include rollback transports.
421   // JsepTransportController can iterate all the DtlsTransports and update the
422   // aggregate states.
423   std::vector<cricket::DtlsTransportInternal*> GetActiveDtlsTransports();
424 
425   // Handlers for signals from Transport.
426   void OnTransportWritableState_n(rtc::PacketTransportInternal* transport)
427       RTC_RUN_ON(network_thread_);
428   void OnTransportReceivingState_n(rtc::PacketTransportInternal* transport)
429       RTC_RUN_ON(network_thread_);
430   void OnTransportGatheringState_n(cricket::IceTransportInternal* transport)
431       RTC_RUN_ON(network_thread_);
432   void OnTransportCandidateGathered_n(cricket::IceTransportInternal* transport,
433                                       const cricket::Candidate& candidate)
434       RTC_RUN_ON(network_thread_);
435   void OnTransportCandidateError_n(cricket::IceTransportInternal* transport,
436                                    const cricket::IceCandidateErrorEvent& event)
437       RTC_RUN_ON(network_thread_);
438   void OnTransportCandidatesRemoved_n(cricket::IceTransportInternal* transport,
439                                       const cricket::Candidates& candidates)
440       RTC_RUN_ON(network_thread_);
441   void OnTransportRoleConflict_n(cricket::IceTransportInternal* transport)
442       RTC_RUN_ON(network_thread_);
443   void OnTransportStateChanged_n(cricket::IceTransportInternal* transport)
444       RTC_RUN_ON(network_thread_);
445   void OnTransportCandidatePairChanged_n(
446       const cricket::CandidatePairChangeEvent& event)
447       RTC_RUN_ON(network_thread_);
448   void UpdateAggregateStates_n() RTC_RUN_ON(network_thread_);
449 
450   void OnRtcpPacketReceived_n(rtc::CopyOnWriteBuffer* packet,
451                               int64_t packet_time_us)
452       RTC_RUN_ON(network_thread_);
453 
454   void OnDtlsHandshakeError(rtc::SSLHandshakeError error);
455 
456   bool OnTransportChanged(const std::string& mid,
457                           cricket::JsepTransport* transport);
458 
459   rtc::Thread* const network_thread_ = nullptr;
460   cricket::PortAllocator* const port_allocator_ = nullptr;
461   AsyncDnsResolverFactoryInterface* const async_dns_resolver_factory_ = nullptr;
462 
463   JsepTransportCollection transports_ RTC_GUARDED_BY(network_thread_);
464   // Aggregate states for Transports.
465   // standardized_ice_connection_state_ is intended to replace
466   // ice_connection_state, see bugs.webrtc.org/9308
467   cricket::IceConnectionState ice_connection_state_ =
468       cricket::kIceConnectionConnecting;
469   PeerConnectionInterface::IceConnectionState
470       standardized_ice_connection_state_ =
471           PeerConnectionInterface::kIceConnectionNew;
472   PeerConnectionInterface::PeerConnectionState combined_connection_state_ =
473       PeerConnectionInterface::PeerConnectionState::kNew;
474   cricket::IceGatheringState ice_gathering_state_ = cricket::kIceGatheringNew;
475 
476   const Config config_;
477   bool active_reset_srtp_params_ RTC_GUARDED_BY(network_thread_);
478 
479   const cricket::SessionDescription* local_desc_ = nullptr;
480   const cricket::SessionDescription* remote_desc_ = nullptr;
481   absl::optional<bool> initial_offerer_;
482 
483   cricket::IceConfig ice_config_;
484   cricket::IceRole ice_role_ = cricket::ICEROLE_CONTROLLING;
485   uint64_t ice_tiebreaker_ = rtc::CreateRandomId64();
486   rtc::scoped_refptr<rtc::RTCCertificate> certificate_;
487 
488   BundleManager bundles_;
489 };
490 
491 }  // namespace webrtc
492 
493 #endif  // PC_JSEP_TRANSPORT_CONTROLLER_H_
494