/* * srtp_priv.h * * private internal data structures and functions for libSRTP * * David A. McGrew * Cisco Systems, Inc. */ /* * * Copyright (c) 2001-2006 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 #include "srtp.h" #include "rdbx.h" #include "rdb.h" #include "integers.h" /* * an srtp_hdr_t represents the srtp header * * 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 /* * 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. */ 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 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 version:2; /* protocol version */ unsigned int p:1; /* padding flag */ unsigned int count:5; /* varies by packet type */ unsigned int pt:8; /* payload type */ uint16_t length; /* len of uint32s of packet less header */ } rtcp_common_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 /* * 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. */ err_status_t srtp_stream_init_keys(srtp_stream_t srtp, const void *key); /* * libsrtp internal datatypes */ typedef enum direction_t { dir_unknown = 0, dir_srtp_sender = 1, dir_srtp_receiver = 2 } direction_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 * cipher_t and auth_t pointers will point to the same structures */ typedef struct srtp_stream_ctx_t { uint32_t ssrc; cipher_t *rtp_cipher; auth_t *rtp_auth; rdbx_t rtp_rdbx; sec_serv_t rtp_services; cipher_t *rtcp_cipher; auth_t *rtcp_auth; rdb_t rtcp_rdb; sec_serv_t rtcp_services; key_limit_ctx_t *limit; direction_t direction; struct srtp_stream_ctx_t *next; /* linked list of streams */ } srtp_stream_ctx_t; /* * an srtp_ctx_t holds a stream list and a service description */ typedef struct srtp_ctx_t { srtp_stream_ctx_t *stream_list; /* linked list of streams */ srtp_stream_ctx_t *stream_template; /* act as template for other streams */ } srtp_ctx_t; /* * 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.stream = strm; \ data.event = evnt; \ srtp_event_handler(&data); \ } #endif /* SRTP_PRIV_H */