1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
|
/*
* Copyright 2017 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.
*/
#ifndef PC_SRTP_SESSION_H_
#define PC_SRTP_SESSION_H_
#include <vector>
#include "api/scoped_refptr.h"
#include "rtc_base/critical_section.h"
#include "rtc_base/thread_checker.h"
// Forward declaration to avoid pulling in libsrtp headers here
struct srtp_event_data_t;
struct srtp_ctx_t_;
namespace cricket {
// Prohibits webrtc from initializing libsrtp. This can be used if libsrtp is
// initialized by another library or explicitly. Note that this must be called
// before creating an SRTP session with WebRTC.
void ProhibitLibsrtpInitialization();
// 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,
size_t len,
const std::vector<int>& extension_ids);
bool UpdateSend(int cs,
const uint8_t* key,
size_t len,
const std::vector<int>& extension_ids);
// 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,
size_t len,
const std::vector<int>& extension_ids);
bool UpdateRecv(int cs,
const uint8_t* key,
size_t len,
const std::vector<int>& extension_ids);
// 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);
int GetSrtpOverhead() const;
// If external auth is enabled, SRTP will write a dummy auth tag that then
// later must get replaced before the packet is sent out. Only supported for
// non-GCM cipher suites and can be checked through "IsExternalAuthActive"
// if it is actually used. This method is only valid before the RTP params
// have been set.
void EnableExternalAuth();
bool IsExternalAuthEnabled() const;
// A SRTP session supports external creation of the auth tag if a non-GCM
// cipher is used. This method is only valid after the RTP params have
// been set.
bool IsExternalAuthActive() const;
private:
bool DoSetKey(int type,
int cs,
const uint8_t* key,
size_t len,
const std::vector<int>& extension_ids);
bool SetKey(int type,
int cs,
const uint8_t* key,
size_t len,
const std::vector<int>& extension_ids);
bool UpdateKey(int type,
int cs,
const uint8_t* key,
size_t len,
const std::vector<int>& extension_ids);
// Returns send stream current packet index from srtp db.
bool GetSendStreamPacketIndex(void* data, int in_len, int64_t* index);
// These methods are responsible for initializing libsrtp (if the usage count
// is incremented from 0 to 1) or deinitializing it (when decremented from 1
// to 0).
//
// Returns true if successful (will always be successful if already inited).
static bool IncrementLibsrtpUsageCountAndMaybeInit();
static void DecrementLibsrtpUsageCountAndMaybeDeinit();
void HandleEvent(const srtp_event_data_t* ev);
static void HandleEventThunk(srtp_event_data_t* ev);
rtc::ThreadChecker thread_checker_;
srtp_ctx_t_* session_ = nullptr;
int rtp_auth_tag_len_ = 0;
int rtcp_auth_tag_len_ = 0;
bool inited_ = false;
static rtc::GlobalLock lock_;
int last_send_seq_num_ = -1;
bool external_auth_active_ = false;
bool external_auth_enabled_ = false;
int decryption_failure_count_ = 0;
RTC_DISALLOW_COPY_AND_ASSIGN(SrtpSession);
};
} // namespace cricket
#endif // PC_SRTP_SESSION_H_
|
