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
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
|
/*
* srtp_priv.h
*
* private internal data structures and functions for libSRTP
*
* David A. McGrew
* Cisco Systems, Inc.
*/
/*
*
* Copyright (c) 2001-2017 Cisco Systems, Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 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.
*
* Neither the name of the Cisco Systems, Inc. nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "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
* COPYRIGHT HOLDERS OR CONTRIBUTORS 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 SRTP_PRIV_H
#define SRTP_PRIV_H
// Leave this as the top level import. Ensures the existence of defines
#include "config.h"
#include "srtp.h"
#include "rdbx.h"
#include "rdb.h"
#include "integers.h"
#include "cipher.h"
#include "auth.h"
#include "aes.h"
#include "key.h"
#include "crypto_kernel.h"
#ifdef __cplusplus
extern "C" {
#endif
#define SRTP_VER_STRING PACKAGE_STRING
#define SRTP_VERSION PACKAGE_VERSION
typedef struct srtp_stream_ctx_t_ srtp_stream_ctx_t;
typedef srtp_stream_ctx_t *srtp_stream_t;
/*
* the following declarations are libSRTP internal functions
*/
/*
* srtp_get_stream(ssrc) returns a pointer to the stream corresponding
* to ssrc, or NULL if no stream exists for that ssrc
*/
srtp_stream_t srtp_get_stream(srtp_t srtp, uint32_t ssrc);
/*
* srtp_stream_init_keys(s, k) (re)initializes the srtp_stream_t s by
* deriving all of the needed keys using the KDF and the key k.
*/
srtp_err_status_t srtp_stream_init_keys(srtp_stream_ctx_t *srtp,
srtp_master_key_t *master_key,
const unsigned int current_mki_index);
/*
* srtp_stream_init_all_master_keys(s, k, m) (re)initializes the srtp_stream_t s
* by deriving all of the needed keys for all the master keys using the KDF and
* the keys from k.
*/
srtp_err_status_t srtp_steam_init_all_master_keys(
srtp_stream_ctx_t *srtp,
unsigned char *key,
srtp_master_key_t **keys,
const unsigned int max_master_keys);
/*
* srtp_stream_init(s, p) initializes the srtp_stream_t s to
* use the policy at the location p
*/
srtp_err_status_t srtp_stream_init(srtp_stream_t srtp, const srtp_policy_t *p);
/*
* libsrtp internal datatypes
*/
typedef enum direction_t {
dir_unknown = 0,
dir_srtp_sender = 1,
dir_srtp_receiver = 2
} direction_t;
/*
* srtp_session_keys_t will contain the encryption, hmac, salt keys
* for both SRTP and SRTCP. The session keys will also contain the
* MKI ID which is used to identify the session keys.
*/
typedef struct srtp_session_keys_t {
srtp_cipher_t *rtp_cipher;
srtp_cipher_t *rtp_xtn_hdr_cipher;
srtp_auth_t *rtp_auth;
srtp_cipher_t *rtcp_cipher;
srtp_auth_t *rtcp_auth;
uint8_t salt[SRTP_AEAD_SALT_LEN];
uint8_t c_salt[SRTP_AEAD_SALT_LEN];
uint8_t *mki_id;
unsigned int mki_size;
srtp_key_limit_ctx_t *limit;
} srtp_session_keys_t;
/*
* an srtp_stream_t has its own SSRC, encryption key, authentication
* key, sequence number, and replay database
*
* note that the keys might not actually be unique, in which case the
* srtp_cipher_t and srtp_auth_t pointers will point to the same structures
*/
typedef struct srtp_stream_ctx_t_ {
uint32_t ssrc;
srtp_session_keys_t *session_keys;
unsigned int num_master_keys;
srtp_rdbx_t rtp_rdbx;
srtp_sec_serv_t rtp_services;
srtp_rdb_t rtcp_rdb;
srtp_sec_serv_t rtcp_services;
direction_t direction;
int allow_repeat_tx;
srtp_ekt_stream_t ekt;
int *enc_xtn_hdr;
int enc_xtn_hdr_count;
uint32_t pending_roc;
struct srtp_stream_ctx_t_ *next; /* linked list of streams */
} strp_stream_ctx_t_;
/*
* an srtp_ctx_t holds a stream list and a service description
*/
typedef struct srtp_ctx_t_ {
struct srtp_stream_ctx_t_ *stream_list; /* linked list of streams */
struct srtp_stream_ctx_t_ *stream_template; /* act as template for other */
/* streams */
void *user_data; /* user custom data */
} srtp_ctx_t_;
/*
* srtp_hdr_t represents an RTP or SRTP header. The bit-fields in
* this structure should be declared "unsigned int" instead of
* "unsigned char", but doing so causes the MS compiler to not
* fully pack the bit fields.
*
* In this implementation, an srtp_hdr_t is assumed to be 32-bit aligned
*
* (note that this definition follows that of RFC 1889 Appendix A, but
* is not identical)
*/
#ifndef WORDS_BIGENDIAN
typedef struct {
unsigned char cc : 4; /* CSRC count */
unsigned char x : 1; /* header extension flag */
unsigned char p : 1; /* padding flag */
unsigned char version : 2; /* protocol version */
unsigned char pt : 7; /* payload type */
unsigned char m : 1; /* marker bit */
uint16_t seq; /* sequence number */
uint32_t ts; /* timestamp */
uint32_t ssrc; /* synchronization source */
} srtp_hdr_t;
#else /* BIG_ENDIAN */
typedef struct {
unsigned char version : 2; /* protocol version */
unsigned char p : 1; /* padding flag */
unsigned char x : 1; /* header extension flag */
unsigned char cc : 4; /* CSRC count */
unsigned char m : 1; /* marker bit */
unsigned char pt : 7; /* payload type */
uint16_t seq; /* sequence number */
uint32_t ts; /* timestamp */
uint32_t ssrc; /* synchronization source */
} srtp_hdr_t;
#endif
typedef struct {
uint16_t profile_specific; /* profile-specific info */
uint16_t length; /* number of 32-bit words in extension */
} srtp_hdr_xtnd_t;
/*
* srtcp_hdr_t represents a secure rtcp header
*
* in this implementation, an srtcp header is assumed to be 32-bit
* alinged
*/
#ifndef WORDS_BIGENDIAN
typedef struct {
unsigned char rc : 5; /* reception report count */
unsigned char p : 1; /* padding flag */
unsigned char version : 2; /* protocol version */
unsigned char pt : 8; /* payload type */
uint16_t len; /* length */
uint32_t ssrc; /* synchronization source */
} srtcp_hdr_t;
typedef struct {
unsigned int index : 31; /* srtcp packet index in network order! */
unsigned int e : 1; /* encrypted? 1=yes */
/* optional mikey/etc go here */
/* and then the variable-length auth tag */
} srtcp_trailer_t;
#else /* BIG_ENDIAN */
typedef struct {
unsigned char version : 2; /* protocol version */
unsigned char p : 1; /* padding flag */
unsigned char rc : 5; /* reception report count */
unsigned char pt : 8; /* payload type */
uint16_t len; /* length */
uint32_t ssrc; /* synchronization source */
} srtcp_hdr_t;
typedef struct {
unsigned int e : 1; /* encrypted? 1=yes */
unsigned int index : 31; /* srtcp packet index */
/* optional mikey/etc go here */
/* and then the variable-length auth tag */
} srtcp_trailer_t;
#endif
/*
* srtp_handle_event(srtp, srtm, evnt) calls the event handling
* function, if there is one.
*
* This macro is not included in the documentation as it is
* an internal-only function.
*/
#define srtp_handle_event(srtp, strm, evnt) \
if (srtp_event_handler) { \
srtp_event_data_t data; \
data.session = srtp; \
data.ssrc = ntohl(strm->ssrc); \
data.event = evnt; \
srtp_event_handler(&data); \
}
#ifdef __cplusplus
}
#endif
#endif /* SRTP_PRIV_H */
|
