Tristan Matthews | 0a329cc | 2013-07-17 13:20:14 -0400 | [diff] [blame] | 1 | /* |
| 2 | * srtp_priv.h |
| 3 | * |
| 4 | * private internal data structures and functions for libSRTP |
| 5 | * |
| 6 | * David A. McGrew |
| 7 | * Cisco Systems, Inc. |
| 8 | */ |
| 9 | /* |
| 10 | * |
| 11 | * Copyright (c) 2001-2006 Cisco Systems, Inc. |
| 12 | * All rights reserved. |
| 13 | * |
| 14 | * Redistribution and use in source and binary forms, with or without |
| 15 | * modification, are permitted provided that the following conditions |
| 16 | * are met: |
| 17 | * |
| 18 | * Redistributions of source code must retain the above copyright |
| 19 | * notice, this list of conditions and the following disclaimer. |
| 20 | * |
| 21 | * Redistributions in binary form must reproduce the above |
| 22 | * copyright notice, this list of conditions and the following |
| 23 | * disclaimer in the documentation and/or other materials provided |
| 24 | * with the distribution. |
| 25 | * |
| 26 | * Neither the name of the Cisco Systems, Inc. nor the names of its |
| 27 | * contributors may be used to endorse or promote products derived |
| 28 | * from this software without specific prior written permission. |
| 29 | * |
| 30 | * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| 31 | * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| 32 | * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS |
| 33 | * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE |
| 34 | * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, |
| 35 | * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES |
| 36 | * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR |
| 37 | * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| 38 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, |
| 39 | * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
| 40 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED |
| 41 | * OF THE POSSIBILITY OF SUCH DAMAGE. |
| 42 | * |
| 43 | */ |
| 44 | |
| 45 | #ifndef SRTP_PRIV_H |
| 46 | #define SRTP_PRIV_H |
| 47 | |
| 48 | #include "srtp.h" |
| 49 | #include "rdbx.h" |
| 50 | #include "rdb.h" |
| 51 | #include "integers.h" |
| 52 | |
| 53 | /* |
| 54 | * an srtp_hdr_t represents the srtp header |
| 55 | * |
| 56 | * in this implementation, an srtp_hdr_t is assumed to be 32-bit aligned |
| 57 | * |
| 58 | * (note that this definition follows that of RFC 1889 Appendix A, but |
| 59 | * is not identical) |
| 60 | */ |
| 61 | |
| 62 | #ifdef _MSC_VER
|
| 63 | # pragma warning(push)
|
| 64 | # pragma warning(disable:4214) // bit field types other than int
|
| 65 | #endif |
| 66 | |
| 67 | #ifndef WORDS_BIGENDIAN |
| 68 | |
| 69 | /* |
| 70 | * srtp_hdr_t represents an RTP or SRTP header. The bit-fields in |
| 71 | * this structure should be declared "unsigned int" instead of |
| 72 | * "unsigned char", but doing so causes the MS compiler to not |
| 73 | * fully pack the bit fields. |
| 74 | */ |
| 75 | typedef struct { |
| 76 | unsigned char cc:4; /* CSRC count */ |
| 77 | unsigned char x:1; /* header extension flag */ |
| 78 | unsigned char p:1; /* padding flag */ |
| 79 | unsigned char version:2; /* protocol version */ |
| 80 | unsigned char pt:7; /* payload type */ |
| 81 | unsigned char m:1; /* marker bit */ |
| 82 | uint16_t seq; /* sequence number */ |
| 83 | uint32_t ts; /* timestamp */ |
| 84 | uint32_t ssrc; /* synchronization source */ |
| 85 | } srtp_hdr_t; |
| 86 | |
| 87 | #else /* BIG_ENDIAN */ |
| 88 | |
| 89 | typedef struct { |
| 90 | unsigned char version:2; /* protocol version */ |
| 91 | unsigned char p:1; /* padding flag */ |
| 92 | unsigned char x:1; /* header extension flag */ |
| 93 | unsigned char cc:4; /* CSRC count */ |
| 94 | unsigned char m:1; /* marker bit */ |
| 95 | unsigned pt:7; /* payload type */ |
| 96 | uint16_t seq; /* sequence number */ |
| 97 | uint32_t ts; /* timestamp */ |
| 98 | uint32_t ssrc; /* synchronization source */ |
| 99 | } srtp_hdr_t; |
| 100 | |
| 101 | #endif |
| 102 |
|
| 103 | |
| 104 | typedef struct { |
| 105 | uint16_t profile_specific; /* profile-specific info */ |
| 106 | uint16_t length; /* number of 32-bit words in extension */ |
| 107 | } srtp_hdr_xtnd_t; |
| 108 | |
| 109 | |
| 110 | /* |
| 111 | * srtcp_hdr_t represents a secure rtcp header |
| 112 | * |
| 113 | * in this implementation, an srtcp header is assumed to be 32-bit |
| 114 | * alinged |
| 115 | */ |
| 116 | |
| 117 | #ifndef WORDS_BIGENDIAN |
| 118 | |
| 119 | typedef struct { |
| 120 | unsigned char rc:5; /* reception report count */ |
| 121 | unsigned char p:1; /* padding flag */ |
| 122 | unsigned char version:2; /* protocol version */ |
| 123 | unsigned char pt:8; /* payload type */ |
| 124 | uint16_t len; /* length */ |
| 125 | uint32_t ssrc; /* synchronization source */ |
| 126 | } srtcp_hdr_t; |
| 127 | |
| 128 | typedef struct { |
| 129 | unsigned int index:31; /* srtcp packet index in network order! */ |
| 130 | unsigned int e:1; /* encrypted? 1=yes */ |
| 131 | /* optional mikey/etc go here */ |
| 132 | /* and then the variable-length auth tag */ |
| 133 | } srtcp_trailer_t; |
| 134 | |
| 135 | |
| 136 | #else /* BIG_ENDIAN */ |
| 137 | |
| 138 | typedef struct { |
| 139 | unsigned char version:2; /* protocol version */ |
| 140 | unsigned char p:1; /* padding flag */ |
| 141 | unsigned char rc:5; /* reception report count */ |
| 142 | unsigned char pt:8; /* payload type */ |
| 143 | uint16_t len; /* length */ |
| 144 | uint32_t ssrc; /* synchronization source */ |
| 145 | } srtcp_hdr_t; |
| 146 | |
| 147 | typedef struct { |
| 148 | unsigned int version:2; /* protocol version */ |
| 149 | unsigned int p:1; /* padding flag */ |
| 150 | unsigned int count:5; /* varies by packet type */ |
| 151 | unsigned int pt:8; /* payload type */ |
| 152 | uint16_t length; /* len of uint32s of packet less header */ |
| 153 | } rtcp_common_t; |
| 154 | |
| 155 | typedef struct { |
| 156 | unsigned int e:1; /* encrypted? 1=yes */ |
| 157 | unsigned int index:31; /* srtcp packet index */ |
| 158 | /* optional mikey/etc go here */ |
| 159 | /* and then the variable-length auth tag */ |
| 160 | } srtcp_trailer_t; |
| 161 | |
| 162 | #endif |
| 163 | |
| 164 | |
| 165 | #ifdef _MSC_VER
|
| 166 | # pragma warning( pop ) |
| 167 | #endif |
| 168 | |
| 169 | |
| 170 | /* |
| 171 | * the following declarations are libSRTP internal functions |
| 172 | */ |
| 173 | |
| 174 | /* |
| 175 | * srtp_get_stream(ssrc) returns a pointer to the stream corresponding |
| 176 | * to ssrc, or NULL if no stream exists for that ssrc |
| 177 | */ |
| 178 | |
| 179 | srtp_stream_t |
| 180 | srtp_get_stream(srtp_t srtp, uint32_t ssrc); |
| 181 | |
| 182 | |
| 183 | /* |
| 184 | * srtp_stream_init_keys(s, k) (re)initializes the srtp_stream_t s by |
| 185 | * deriving all of the needed keys using the KDF and the key k. |
| 186 | */ |
| 187 | |
| 188 | |
| 189 | err_status_t |
| 190 | srtp_stream_init_keys(srtp_stream_t srtp, const void *key); |
| 191 | |
| 192 | /* |
| 193 | * libsrtp internal datatypes |
| 194 | */ |
| 195 | |
| 196 | typedef enum direction_t { |
| 197 | dir_unknown = 0, |
| 198 | dir_srtp_sender = 1, |
| 199 | dir_srtp_receiver = 2 |
| 200 | } direction_t; |
| 201 | |
| 202 | /* |
| 203 | * an srtp_stream_t has its own SSRC, encryption key, authentication |
| 204 | * key, sequence number, and replay database |
| 205 | * |
| 206 | * note that the keys might not actually be unique, in which case the |
| 207 | * cipher_t and auth_t pointers will point to the same structures |
| 208 | */ |
| 209 | |
| 210 | typedef struct srtp_stream_ctx_t { |
| 211 | uint32_t ssrc; |
| 212 | cipher_t *rtp_cipher; |
| 213 | auth_t *rtp_auth; |
| 214 | rdbx_t rtp_rdbx; |
| 215 | sec_serv_t rtp_services; |
| 216 | cipher_t *rtcp_cipher; |
| 217 | auth_t *rtcp_auth; |
| 218 | rdb_t rtcp_rdb; |
| 219 | sec_serv_t rtcp_services; |
| 220 | key_limit_ctx_t *limit; |
| 221 | direction_t direction; |
| 222 | struct srtp_stream_ctx_t *next; /* linked list of streams */ |
| 223 | } srtp_stream_ctx_t; |
| 224 | |
| 225 | |
| 226 | /* |
| 227 | * an srtp_ctx_t holds a stream list and a service description |
| 228 | */ |
| 229 | |
| 230 | typedef struct srtp_ctx_t { |
| 231 | srtp_stream_ctx_t *stream_list; /* linked list of streams */ |
| 232 | srtp_stream_ctx_t *stream_template; /* act as template for other streams */ |
| 233 | } srtp_ctx_t; |
| 234 | |
| 235 | |
| 236 | |
| 237 | /* |
| 238 | * srtp_handle_event(srtp, srtm, evnt) calls the event handling |
| 239 | * function, if there is one. |
| 240 | * |
| 241 | * This macro is not included in the documentation as it is |
| 242 | * an internal-only function. |
| 243 | */ |
| 244 | |
| 245 | #define srtp_handle_event(srtp, strm, evnt) \ |
| 246 | if(srtp_event_handler) { \ |
| 247 | srtp_event_data_t data; \ |
| 248 | data.session = srtp; \ |
| 249 | data.stream = strm; \ |
| 250 | data.event = evnt; \ |
| 251 | srtp_event_handler(&data); \ |
| 252 | } |
| 253 | |
| 254 | |
| 255 | #endif /* SRTP_PRIV_H */ |