Add current version of libSRTP from CVS.

libsrtp/include/srtp_priv.h

+/*
+ * 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);
+
+/*
+ * srtp_stream_init(s, p) initializes the srtp_stream_t s to 
+ * use the policy at the location p
+ */
+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;
+
+/* 
+ * 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;
+  int        allow_repeat_tx;
+  ekt_stream_t ekt; 
+  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 */