Move talk/session/media -> webrtc/pc

talk/session/media/srtpfilter.h

-/*
- * libjingle
- * Copyright 2009 Google Inc.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are met:
- *
- *  1. Redistributions of source code must retain the above copyright notice,
- *     this list of conditions and the following disclaimer.
- *  2. Redistributions in binary form must reproduce the above copyright notice,
- *     this list of conditions and the following disclaimer in the documentation
- *     and/or other materials provided with the distribution.
- *  3. The name of the author may not be used to endorse or promote products
- *     derived from this software without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
- * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
- * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
- * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
- * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
- * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
- * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
- * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
- * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- */
-
-#ifndef TALK_SESSION_MEDIA_SRTPFILTER_H_
-#define TALK_SESSION_MEDIA_SRTPFILTER_H_
-
-#include <list>
-#include <map>
-#include <string>
-#include <vector>
-
-#include "webrtc/base/basictypes.h"
-#include "webrtc/base/criticalsection.h"
-#include "webrtc/base/scoped_ptr.h"
-#include "webrtc/base/sigslotrepeater.h"
-#include "webrtc/base/sslstreamadapter.h"
-#include "webrtc/media/base/cryptoparams.h"
-#include "webrtc/p2p/base/sessiondescription.h"
-
-// Forward declaration to avoid pulling in libsrtp headers here
-struct srtp_event_data_t;
-struct srtp_ctx_t;
-struct srtp_policy_t;
-
-namespace cricket {
-
-// Key is 128 bits and salt is 112 bits == 30 bytes. B64 bloat => 40 bytes.
-extern const int SRTP_MASTER_KEY_BASE64_LEN;
-
-// Needed for DTLS-SRTP
-extern const int SRTP_MASTER_KEY_KEY_LEN;
-extern const int SRTP_MASTER_KEY_SALT_LEN;
-
-class SrtpSession;
-class SrtpStat;
-
-void EnableSrtpDebugging();
-void ShutdownSrtp();
-
-// Class to transform SRTP to/from RTP.
-// Initialize by calling SetSend with the local security params, then call
-// SetRecv once the remote security params are received. At that point
-// Protect/UnprotectRt(c)p can be called to encrypt/decrypt data.
-// TODO: Figure out concurrency policy for SrtpFilter.
-class SrtpFilter {
- public:
-  enum Mode {
-    PROTECT,
-    UNPROTECT
-  };
-  enum Error {
-    ERROR_NONE,
-    ERROR_FAIL,
-    ERROR_AUTH,
-    ERROR_REPLAY,
-  };
-
-  SrtpFilter();
-  ~SrtpFilter();
-
-  // Whether the filter is active (i.e. crypto has been properly negotiated).
-  bool IsActive() const;
-
-  // Indicates which crypto algorithms and keys were contained in the offer.
-  // offer_params should contain a list of available parameters to use, or none,
-  // if crypto is not desired. This must be called before SetAnswer.
-  bool SetOffer(const std::vector<CryptoParams>& offer_params,
-                ContentSource source);
-  // Same as SetAnwer. But multiple calls are allowed to SetProvisionalAnswer
-  // after a call to SetOffer.
-  bool SetProvisionalAnswer(const std::vector<CryptoParams>& answer_params,
-                            ContentSource source);
-  // Indicates which crypto algorithms and keys were contained in the answer.
-  // answer_params should contain the negotiated parameters, which may be none,
-  // if crypto was not desired or could not be negotiated (and not required).
-  // This must be called after SetOffer. If crypto negotiation completes
-  // successfully, this will advance the filter to the active state.
-  bool SetAnswer(const std::vector<CryptoParams>& answer_params,
-                 ContentSource source);
-
-  // Just set up both sets of keys directly.
-  // Used with DTLS-SRTP.
-  bool SetRtpParams(int send_cs,
-                    const uint8_t* send_key,
-                    int send_key_len,
-                    int recv_cs,
-                    const uint8_t* recv_key,
-                    int recv_key_len);
-  bool SetRtcpParams(int send_cs,
-                     const uint8_t* send_key,
-                     int send_key_len,
-                     int recv_cs,
-                     const uint8_t* recv_key,
-                     int recv_key_len);
-
-  // Encrypts/signs an individual RTP/RTCP packet, in-place.
-  // If an HMAC is used, this will increase the packet size.
-  bool ProtectRtp(void* data, int in_len, int max_len, int* out_len);
-  // Overloaded version, outputs packet index.
-  bool ProtectRtp(void* data,
-                  int in_len,
-                  int max_len,
-                  int* out_len,
-                  int64_t* index);
-  bool ProtectRtcp(void* data, int in_len, int max_len, int* out_len);
-  // Decrypts/verifies an invidiual RTP/RTCP packet.
-  // If an HMAC is used, this will decrease the packet size.
-  bool UnprotectRtp(void* data, int in_len, int* out_len);
-  bool UnprotectRtcp(void* data, int in_len, int* out_len);
-
-  // Returns rtp auth params from srtp context.
-  bool GetRtpAuthParams(uint8_t** key, int* key_len, int* tag_len);
-
-  // Update the silent threshold (in ms) for signaling errors.
-  void set_signal_silent_time(uint32_t signal_silent_time_in_ms);
-
-  bool ResetParams();
-
-  sigslot::repeater3<uint32_t, Mode, Error> SignalSrtpError;
-
- protected:
-  bool ExpectOffer(ContentSource source);
-  bool StoreParams(const std::vector<CryptoParams>& params,
-                   ContentSource source);
-  bool ExpectAnswer(ContentSource source);
-  bool DoSetAnswer(const std::vector<CryptoParams>& answer_params,
-                     ContentSource source,
-                     bool final);
-  void CreateSrtpSessions();
-  bool NegotiateParams(const std::vector<CryptoParams>& answer_params,
-                       CryptoParams* selected_params);
-  bool ApplyParams(const CryptoParams& send_params,
-                   const CryptoParams& recv_params);
-  static bool ParseKeyParams(const std::string& params, uint8_t* key, int len);
-
- private:
-  enum State {
-    ST_INIT,           // SRTP filter unused.
-    ST_SENTOFFER,      // Offer with SRTP parameters sent.
-    ST_RECEIVEDOFFER,  // Offer with SRTP parameters received.
-    ST_SENTPRANSWER_NO_CRYPTO,  // Sent provisional answer without crypto.
-    // Received provisional answer without crypto.
-    ST_RECEIVEDPRANSWER_NO_CRYPTO,
-    ST_ACTIVE,         // Offer and answer set.
-    // SRTP filter is active but new parameters are offered.
-    // When the answer is set, the state transitions to ST_ACTIVE or ST_INIT.
-    ST_SENTUPDATEDOFFER,
-    // SRTP filter is active but new parameters are received.
-    // When the answer is set, the state transitions back to ST_ACTIVE.
-    ST_RECEIVEDUPDATEDOFFER,
-    // SRTP filter is active but the sent answer is only provisional.
-    // When the final answer is set, the state transitions to ST_ACTIVE or
-    // ST_INIT.
-    ST_SENTPRANSWER,
-    // SRTP filter is active but the received answer is only provisional.
-    // When the final answer is set, the state transitions to ST_ACTIVE or
-    // ST_INIT.
-    ST_RECEIVEDPRANSWER
-  };
-  State state_;
-  uint32_t signal_silent_time_in_ms_;
-  std::vector<CryptoParams> offer_params_;
-  rtc::scoped_ptr<SrtpSession> send_session_;
-  rtc::scoped_ptr<SrtpSession> recv_session_;
-  rtc::scoped_ptr<SrtpSession> send_rtcp_session_;
-  rtc::scoped_ptr<SrtpSession> recv_rtcp_session_;
-  CryptoParams applied_send_params_;
-  CryptoParams applied_recv_params_;
-};
-
-// Class that wraps a libSRTP session.
-class SrtpSession {
- public:
-  SrtpSession();
-  ~SrtpSession();
-
-  // Configures the session for sending data using the specified
-  // cipher-suite and key. Receiving must be done by a separate session.
-  bool SetSend(int cs, const uint8_t* key, int len);
-  // Configures the session for receiving data using the specified
-  // cipher-suite and key. Sending must be done by a separate session.
-  bool SetRecv(int cs, const uint8_t* key, int len);
-
-  // Encrypts/signs an individual RTP/RTCP packet, in-place.
-  // If an HMAC is used, this will increase the packet size.
-  bool ProtectRtp(void* data, int in_len, int max_len, int* out_len);
-  // Overloaded version, outputs packet index.
-  bool ProtectRtp(void* data,
-                  int in_len,
-                  int max_len,
-                  int* out_len,
-                  int64_t* index);
-  bool ProtectRtcp(void* data, int in_len, int max_len, int* out_len);
-  // Decrypts/verifies an invidiual RTP/RTCP packet.
-  // If an HMAC is used, this will decrease the packet size.
-  bool UnprotectRtp(void* data, int in_len, int* out_len);
-  bool UnprotectRtcp(void* data, int in_len, int* out_len);
-
-  // Helper method to get authentication params.
-  bool GetRtpAuthParams(uint8_t** key, int* key_len, int* tag_len);
-
-  // Update the silent threshold (in ms) for signaling errors.
-  void set_signal_silent_time(uint32_t signal_silent_time_in_ms);
-
-  // Calls srtp_shutdown if it's initialized.
-  static void Terminate();
-
-  sigslot::repeater3<uint32_t, SrtpFilter::Mode, SrtpFilter::Error>
-      SignalSrtpError;
-
- private:
-  bool SetKey(int type, int cs, const uint8_t* key, int len);
-    // Returns send stream current packet index from srtp db.
-  bool GetSendStreamPacketIndex(void* data, int in_len, int64_t* index);
-
-  static bool Init();
-  void HandleEvent(const srtp_event_data_t* ev);
-  static void HandleEventThunk(srtp_event_data_t* ev);
-
-  static std::list<SrtpSession*>* sessions();
-
-  srtp_ctx_t* session_;
-  int rtp_auth_tag_len_;
-  int rtcp_auth_tag_len_;
-  rtc::scoped_ptr<SrtpStat> srtp_stat_;
-  static bool inited_;
-  static rtc::GlobalLockPod lock_;
-  int last_send_seq_num_;
-  RTC_DISALLOW_COPY_AND_ASSIGN(SrtpSession);
-};
-
-// Class that collects failures of SRTP.
-class SrtpStat {
- public:
-  SrtpStat();
-
-  // Report RTP protection results to the handler.
-  void AddProtectRtpResult(uint32_t ssrc, int result);
-  // Report RTP unprotection results to the handler.
-  void AddUnprotectRtpResult(uint32_t ssrc, int result);
-  // Report RTCP protection results to the handler.
-  void AddProtectRtcpResult(int result);
-  // Report RTCP unprotection results to the handler.
-  void AddUnprotectRtcpResult(int result);
-
-  // Get silent time (in ms) for SRTP statistics handler.
-  uint32_t signal_silent_time() const { return signal_silent_time_; }
-  // Set silent time (in ms) for SRTP statistics handler.
-  void set_signal_silent_time(uint32_t signal_silent_time) {
-    signal_silent_time_ = signal_silent_time;
-  }
-
-  // Sigslot for reporting errors.
-  sigslot::signal3<uint32_t, SrtpFilter::Mode, SrtpFilter::Error>
-      SignalSrtpError;
-
- private:
-  // For each different ssrc and error, we collect statistics separately.
-  struct FailureKey {
-    FailureKey()
-        : ssrc(0),
-          mode(SrtpFilter::PROTECT),
-          error(SrtpFilter::ERROR_NONE) {
-    }
-    FailureKey(uint32_t in_ssrc,
-               SrtpFilter::Mode in_mode,
-               SrtpFilter::Error in_error)
-        : ssrc(in_ssrc), mode(in_mode), error(in_error) {}
-    bool operator <(const FailureKey& key) const {
-      return
-          (ssrc < key.ssrc) ||
-          (ssrc == key.ssrc && mode < key.mode) ||
-          (ssrc == key.ssrc && mode == key.mode && error < key.error);
-    }
-    uint32_t ssrc;
-    SrtpFilter::Mode mode;
-    SrtpFilter::Error error;
-  };
-  // For tracing conditions for signaling, currently we only use
-  // last_signal_time.  Wrap this as a struct so that later on, if we need any
-  // other improvements, it will be easier.
-  struct FailureStat {
-    FailureStat()
-        : last_signal_time(0) {
-    }
-    explicit FailureStat(uint32_t in_last_signal_time)
-        : last_signal_time(in_last_signal_time) {}
-    void Reset() {
-      last_signal_time = 0;
-    }
-    uint32_t last_signal_time;
-  };
-
-  // Inspect SRTP result and signal error if needed.
-  void HandleSrtpResult(const FailureKey& key);
-
-  std::map<FailureKey, FailureStat> failures_;
-  // Threshold in ms to silent the signaling errors.
-  uint32_t signal_silent_time_;
-
-  RTC_DISALLOW_COPY_AND_ASSIGN(SrtpStat);
-};
-
-}  // namespace cricket
-
-#endif  // TALK_SESSION_MEDIA_SRTPFILTER_H_