139 lines
4.9 KiB
C++
139 lines
4.9 KiB
C++
/*
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* Copyright 2017 The WebRTC project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#ifndef PC_SRTP_SESSION_H_
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#define PC_SRTP_SESSION_H_
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#include <vector>
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#include "api/scoped_refptr.h"
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#include "rtc_base/constructor_magic.h"
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#include "rtc_base/synchronization/mutex.h"
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#include "rtc_base/thread_checker.h"
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// Forward declaration to avoid pulling in libsrtp headers here
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struct srtp_event_data_t;
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struct srtp_ctx_t_;
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namespace cricket {
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// Prohibits webrtc from initializing libsrtp. This can be used if libsrtp is
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// initialized by another library or explicitly. Note that this must be called
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// before creating an SRTP session with WebRTC.
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void ProhibitLibsrtpInitialization();
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// Class that wraps a libSRTP session.
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class SrtpSession {
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public:
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SrtpSession();
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~SrtpSession();
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// Configures the session for sending data using the specified
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// cipher-suite and key. Receiving must be done by a separate session.
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bool SetSend(int cs,
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const uint8_t* key,
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size_t len,
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const std::vector<int>& extension_ids);
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bool UpdateSend(int cs,
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const uint8_t* key,
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size_t len,
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const std::vector<int>& extension_ids);
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// Configures the session for receiving data using the specified
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// cipher-suite and key. Sending must be done by a separate session.
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bool SetRecv(int cs,
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const uint8_t* key,
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size_t len,
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const std::vector<int>& extension_ids);
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bool UpdateRecv(int cs,
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const uint8_t* key,
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size_t len,
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const std::vector<int>& extension_ids);
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// Encrypts/signs an individual RTP/RTCP packet, in-place.
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// If an HMAC is used, this will increase the packet size.
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bool ProtectRtp(void* data, int in_len, int max_len, int* out_len);
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// Overloaded version, outputs packet index.
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bool ProtectRtp(void* data,
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int in_len,
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int max_len,
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int* out_len,
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int64_t* index);
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bool ProtectRtcp(void* data, int in_len, int max_len, int* out_len);
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// Decrypts/verifies an invidiual RTP/RTCP packet.
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// If an HMAC is used, this will decrease the packet size.
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bool UnprotectRtp(void* data, int in_len, int* out_len);
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bool UnprotectRtcp(void* data, int in_len, int* out_len);
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// Helper method to get authentication params.
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bool GetRtpAuthParams(uint8_t** key, int* key_len, int* tag_len);
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int GetSrtpOverhead() const;
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// If external auth is enabled, SRTP will write a dummy auth tag that then
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// later must get replaced before the packet is sent out. Only supported for
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// non-GCM cipher suites and can be checked through "IsExternalAuthActive"
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// if it is actually used. This method is only valid before the RTP params
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// have been set.
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void EnableExternalAuth();
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bool IsExternalAuthEnabled() const;
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// A SRTP session supports external creation of the auth tag if a non-GCM
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// cipher is used. This method is only valid after the RTP params have
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// been set.
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bool IsExternalAuthActive() const;
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private:
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bool DoSetKey(int type,
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int cs,
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const uint8_t* key,
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size_t len,
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const std::vector<int>& extension_ids);
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bool SetKey(int type,
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int cs,
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const uint8_t* key,
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size_t len,
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const std::vector<int>& extension_ids);
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bool UpdateKey(int type,
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int cs,
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const uint8_t* key,
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size_t len,
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const std::vector<int>& extension_ids);
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// Returns send stream current packet index from srtp db.
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bool GetSendStreamPacketIndex(void* data, int in_len, int64_t* index);
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// These methods are responsible for initializing libsrtp (if the usage count
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// is incremented from 0 to 1) or deinitializing it (when decremented from 1
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// to 0).
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//
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// Returns true if successful (will always be successful if already inited).
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static bool IncrementLibsrtpUsageCountAndMaybeInit();
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static void DecrementLibsrtpUsageCountAndMaybeDeinit();
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void HandleEvent(const srtp_event_data_t* ev);
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static void HandleEventThunk(srtp_event_data_t* ev);
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rtc::ThreadChecker thread_checker_;
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srtp_ctx_t_* session_ = nullptr;
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int rtp_auth_tag_len_ = 0;
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int rtcp_auth_tag_len_ = 0;
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bool inited_ = false;
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static webrtc::GlobalMutex lock_;
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int last_send_seq_num_ = -1;
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bool external_auth_active_ = false;
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bool external_auth_enabled_ = false;
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int decryption_failure_count_ = 0;
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RTC_DISALLOW_COPY_AND_ASSIGN(SrtpSession);
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};
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} // namespace cricket
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#endif // PC_SRTP_SESSION_H_
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