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Diffstat (limited to 'include/srtp.h')
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diff --git a/include/srtp.h b/include/srtp.h deleted file mode 100644 index bbaac95..0000000 --- a/include/srtp.h +++ /dev/null @@ -1,933 +0,0 @@ -/* - * srtp.h - * - * interface to 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_H -#define SRTP_H - -#ifdef __cplusplus -extern "C" { -#endif - -#include "crypto_kernel.h" - -/** - * @defgroup SRTP Secure RTP - * - * @brief libSRTP provides functions for protecting RTP and RTCP. See - * Section @ref Overview for an introduction to the use of the library. - * - * @{ - */ - -/* - * SRTP_MASTER_KEY_LEN is the nominal master key length supported by libSRTP - */ - -#define SRTP_MASTER_KEY_LEN 30 - -/* - * SRTP_MAX_KEY_LEN is the maximum key length supported by libSRTP - */ -#define SRTP_MAX_KEY_LEN 64 - -/* - * SRTP_MAX_TAG_LEN is the maximum tag length supported by libSRTP - */ - -#define SRTP_MAX_TAG_LEN 12 - -/** - * SRTP_MAX_TRAILER_LEN is the maximum length of the SRTP trailer - * (authentication tag and MKI) supported by libSRTP. This value is - * the maximum number of octets that will be added to an RTP packet by - * srtp_protect(). - * - * @brief the maximum number of octets added by srtp_protect(). - */ -#define SRTP_MAX_TRAILER_LEN SRTP_MAX_TAG_LEN - -/* - * nota bene: since libSRTP doesn't support the use of the MKI, the - * SRTP_MAX_TRAILER_LEN value is just the maximum tag length - */ - -/** - * @brief sec_serv_t describes a set of security services. - * - * A sec_serv_t enumeration is used to describe the particular - * security services that will be applied by a particular crypto - * policy (or other mechanism). - */ - -typedef enum { - sec_serv_none = 0, /**< no services */ - sec_serv_conf = 1, /**< confidentiality */ - sec_serv_auth = 2, /**< authentication */ - sec_serv_conf_and_auth = 3 /**< confidentiality and authentication */ -} sec_serv_t; - -/** - * @brief crypto_policy_t describes a particular crypto policy that - * can be applied to an SRTP stream. - * - * A crypto_policy_t describes a particular cryptographic policy that - * can be applied to an SRTP or SRTCP stream. An SRTP session policy - * consists of a list of these policies, one for each SRTP stream - * in the session. - */ - -typedef struct crypto_policy_t { - cipher_type_id_t cipher_type; /**< An integer representing - * the type of cipher. */ - int cipher_key_len; /**< The length of the cipher key - * in octets. */ - auth_type_id_t auth_type; /**< An integer representing the - * authentication function. */ - int auth_key_len; /**< The length of the authentication - * function key in octets. */ - int auth_tag_len; /**< The length of the authentication - * tag in octets. */ - sec_serv_t sec_serv; /**< The flag indicating the security - * services to be applied. */ -} crypto_policy_t; - - -/** - * @brief ssrc_type_t describes the type of an SSRC. - * - * An ssrc_type_t enumeration is used to indicate a type of SSRC. See - * @ref srtp_policy_t for more informataion. - */ - -typedef enum { - ssrc_undefined = 0, /**< Indicates an undefined SSRC type. */ - ssrc_specific = 1, /**< Indicates a specific SSRC value */ - ssrc_any_inbound = 2, /**< Indicates any inbound SSRC value - (i.e. a value that is used in the - function srtp_unprotect()) */ - ssrc_any_outbound = 3 /**< Indicates any outbound SSRC value - (i.e. a value that is used in the - function srtp_protect()) */ -} ssrc_type_t; - -/** - * @brief An ssrc_t represents a particular SSRC value, or a `wildcard' SSRC. - * - * An ssrc_t represents a particular SSRC value (if its type is - * ssrc_specific), or a wildcard SSRC value that will match all - * outbound SSRCs (if its type is ssrc_any_outbound) or all inbound - * SSRCs (if its type is ssrc_any_inbound). - * - */ - -typedef struct { - ssrc_type_t type; /**< The type of this particular SSRC */ - unsigned int value; /**< The value of this SSRC, if it is not a wildcard */ -} ssrc_t; - - -/** - * @brief points to an EKT policy - */ -typedef struct ekt_policy_ctx_t *ekt_policy_t; - - -/** - * @brief points to EKT stream data - */ -typedef struct ekt_stream_ctx_t *ekt_stream_t; - - -/** - * @brief represents the policy for an SRTP session. - * - * A single srtp_policy_t struct represents the policy for a single - * SRTP stream, and a linked list of these elements represents the - * policy for an entire SRTP session. Each element contains the SRTP - * and SRTCP crypto policies for that stream, a pointer to the SRTP - * master key for that stream, the SSRC describing that stream, or a - * flag indicating a `wildcard' SSRC value, and a `next' field that - * holds a pointer to the next element in the list of policy elements, - * or NULL if it is the last element. - * - * The wildcard value SSRC_ANY_INBOUND matches any SSRC from an - * inbound stream that for which there is no explicit SSRC entry in - * another policy element. Similarly, the value SSRC_ANY_OUTBOUND - * will matches any SSRC from an outbound stream that does not appear - * in another policy element. Note that wildcard SSRCs &b cannot be - * used to match both inbound and outbound traffic. This restriction - * is intentional, and it allows libSRTP to ensure that no security - * lapses result from accidental re-use of SSRC values during key - * sharing. - * - * - * @warning The final element of the list @b must have its `next' pointer - * set to NULL. - */ - -typedef struct srtp_policy_t { - ssrc_t ssrc; /**< The SSRC value of stream, or the - * flags SSRC_ANY_INBOUND or - * SSRC_ANY_OUTBOUND if key sharing - * is used for this policy element. - */ - crypto_policy_t rtp; /**< SRTP crypto policy. */ - crypto_policy_t rtcp; /**< SRTCP crypto policy. */ - unsigned char *key; /**< Pointer to the SRTP master key for - * this stream. */ - ekt_policy_t ekt; /**< Pointer to the EKT policy structure - * for this stream (if any) */ - unsigned long window_size; /**< The window size to use for replay - * protection. */ - int allow_repeat_tx; /**< Whether retransmissions of - * packets with the same sequence number - * are allowed. (Note that such repeated - * transmissions must have the same RTP - * payload, or a severe security weakness - * is introduced!) */ - struct srtp_policy_t *next; /**< Pointer to next stream policy. */ -} srtp_policy_t; - - - - -/** - * @brief An srtp_t points to an SRTP session structure. - * - * The typedef srtp_t is a pointer to a structure that represents - * an SRTP session. This datatype is intentially opaque in - * order to separate the interface from the implementation. - * - * An SRTP session consists of all of the traffic sent to the RTP and - * RTCP destination transport addresses, using the RTP/SAVP (Secure - * Audio/Video Profile). A session can be viewed as a set of SRTP - * streams, each of which originates with a different participant. - */ - -typedef struct srtp_ctx_t *srtp_t; - - -/** - * @brief An srtp_stream_t points to an SRTP stream structure. - * - * The typedef srtp_stream_t is a pointer to a structure that - * represents an SRTP stream. This datatype is intentionally - * opaque in order to separate the interface from the implementation. - * - * An SRTP stream consists of all of the traffic sent to an SRTP - * session by a single participant. A session can be viewed as - * a set of streams. - * - */ -typedef struct srtp_stream_ctx_t *srtp_stream_t; - - - -/** - * @brief srtp_init() initializes the srtp library. - * - * @warning This function @b must be called before any other srtp - * functions. - */ - -err_status_t -srtp_init(void); - -/** - * @brief srtp_protect() is the Secure RTP sender-side packet processing - * function. - * - * The function call srtp_protect(ctx, rtp_hdr, len_ptr) applies SRTP - * protection to the RTP packet rtp_hdr (which has length *len_ptr) using - * the SRTP context ctx. If err_status_ok is returned, then rtp_hdr - * points to the resulting SRTP packet and *len_ptr is the number of - * octets in that packet; otherwise, no assumptions should be made - * about the value of either data elements. - * - * The sequence numbers of the RTP packets presented to this function - * need not be consecutive, but they @b must be out of order by less - * than 2^15 = 32,768 packets. - * - * @warning This function assumes that it can write the authentication - * tag into the location in memory immediately following the RTP - * packet, and assumes that the RTP packet is aligned on a 32-bit - * boundary. - * - * @param ctx is the SRTP context to use in processing the packet. - * - * @param rtp_hdr is a pointer to the RTP packet (before the call); after - * the function returns, it points to the srtp packet. - * - * @param len_ptr is a pointer to the length in octets of the complete - * RTP packet (header and body) before the function call, and of the - * complete SRTP packet after the call, if err_status_ok was returned. - * Otherwise, the value of the data to which it points is undefined. - * - * @return - * - err_status_ok no problems - * - err_status_replay_fail rtp sequence number was non-increasing - * - @e other failure in cryptographic mechanisms - */ - -err_status_t -srtp_protect(srtp_t ctx, void *rtp_hdr, int *len_ptr); - -/** - * @brief srtp_unprotect() is the Secure RTP receiver-side packet - * processing function. - * - * The function call srtp_unprotect(ctx, srtp_hdr, len_ptr) verifies - * the Secure RTP protection of the SRTP packet pointed to by srtp_hdr - * (which has length *len_ptr), using the SRTP context ctx. If - * err_status_ok is returned, then srtp_hdr points to the resulting - * RTP packet and *len_ptr is the number of octets in that packet; - * otherwise, no assumptions should be made about the value of either - * data elements. - * - * The sequence numbers of the RTP packets presented to this function - * need not be consecutive, but they @b must be out of order by less - * than 2^15 = 32,768 packets. - * - * @warning This function assumes that the SRTP packet is aligned on a - * 32-bit boundary. - * - * @param ctx is a pointer to the srtp_t which applies to the - * particular packet. - * - * @param srtp_hdr is a pointer to the header of the SRTP packet - * (before the call). after the function returns, it points to the - * rtp packet if err_status_ok was returned; otherwise, the value of - * the data to which it points is undefined. - * - * @param len_ptr is a pointer to the length in octets of the complete - * srtp packet (header and body) before the function call, and of the - * complete rtp packet after the call, if err_status_ok was returned. - * Otherwise, the value of the data to which it points is undefined. - * - * @return - * - err_status_ok if the RTP packet is valid. - * - err_status_auth_fail if the SRTP packet failed the message - * authentication check. - * - err_status_replay_fail if the SRTP packet is a replay (e.g. packet has - * already been processed and accepted). - * - [other] if there has been an error in the cryptographic mechanisms. - * - */ - -err_status_t -srtp_unprotect(srtp_t ctx, void *srtp_hdr, int *len_ptr); - - -/** - * @brief srtp_create() allocates and initializes an SRTP session. - - * The function call srtp_create(session, policy, key) allocates and - * initializes an SRTP session context, applying the given policy and - * key. - * - * @param session is the SRTP session to which the policy is to be added. - * - * @param policy is the srtp_policy_t struct that describes the policy - * for the session. The struct may be a single element, or it may be - * the head of a list, in which case each element of the list is - * processed. It may also be NULL, in which case streams should be added - * later using srtp_add_stream(). The final element of the list @b must - * have its `next' field set to NULL. - * - * @return - * - err_status_ok if creation succeded. - * - err_status_alloc_fail if allocation failed. - * - err_status_init_fail if initialization failed. - */ - -err_status_t -srtp_create(srtp_t *session, const srtp_policy_t *policy); - - -/** - * @brief srtp_add_stream() allocates and initializes an SRTP stream - * within a given SRTP session. - * - * The function call srtp_add_stream(session, policy) allocates and - * initializes a new SRTP stream within a given, previously created - * session, applying the policy given as the other argument to that - * stream. - * - * @return values: - * - err_status_ok if stream creation succeded. - * - err_status_alloc_fail if stream allocation failed - * - err_status_init_fail if stream initialization failed. - */ - -err_status_t -srtp_add_stream(srtp_t session, - const srtp_policy_t *policy); - - -/** - * @brief srtp_remove_stream() deallocates an SRTP stream. - * - * The function call srtp_remove_stream(session, ssrc) removes - * the SRTP stream with the SSRC value ssrc from the SRTP session - * context given by the argument session. - * - * @param session is the SRTP session from which the stream - * will be removed. - * - * @param ssrc is the SSRC value of the stream to be removed. - * - * @warning Wildcard SSRC values cannot be removed from a - * session. - * - * @return - * - err_status_ok if the stream deallocation succeded. - * - [other] otherwise. - * - */ - -err_status_t -srtp_remove_stream(srtp_t session, unsigned int ssrc); - -/** - * @brief crypto_policy_set_rtp_default() sets a crypto policy - * structure to the SRTP default policy for RTP protection. - * - * @param p is a pointer to the policy structure to be set - * - * The function call crypto_policy_set_rtp_default(&p) sets the - * crypto_policy_t at location p to the SRTP default policy for RTP - * protection, as defined in the specification. This function is a - * convenience that helps to avoid dealing directly with the policy - * data structure. You are encouraged to initialize policy elements - * with this function call. Doing so may allow your code to be - * forward compatible with later versions of libSRTP that include more - * elements in the crypto_policy_t datatype. - * - * @return void. - * - */ - -void -crypto_policy_set_rtp_default(crypto_policy_t *p); - -/** - * @brief crypto_policy_set_rtcp_default() sets a crypto policy - * structure to the SRTP default policy for RTCP protection. - * - * @param p is a pointer to the policy structure to be set - * - * The function call crypto_policy_set_rtcp_default(&p) sets the - * crypto_policy_t at location p to the SRTP default policy for RTCP - * protection, as defined in the specification. This function is a - * convenience that helps to avoid dealing directly with the policy - * data structure. You are encouraged to initialize policy elements - * with this function call. Doing so may allow your code to be - * forward compatible with later versions of libSRTP that include more - * elements in the crypto_policy_t datatype. - * - * @return void. - * - */ - -void -crypto_policy_set_rtcp_default(crypto_policy_t *p); - -/** - * @brief crypto_policy_set_aes_cm_128_hmac_sha1_80() sets a crypto - * policy structure to the SRTP default policy for RTP protection. - * - * @param p is a pointer to the policy structure to be set - * - * The function crypto_policy_set_aes_cm_128_hmac_sha1_80() is a - * synonym for crypto_policy_set_rtp_default(). It conforms to the - * naming convention used in - * http://www.ietf.org/internet-drafts/draft-ietf-mmusic-sdescriptions-12.txt - * - * @return void. - * - */ - -#define crypto_policy_set_aes_cm_128_hmac_sha1_80(p) crypto_policy_set_rtp_default(p) - - -/** - * @brief crypto_policy_set_aes_cm_128_hmac_sha1_32() sets a crypto - * policy structure to a short-authentication tag policy - * - * @param p is a pointer to the policy structure to be set - * - * The function call crypto_policy_set_aes_cm_128_hmac_sha1_32(&p) - * sets the crypto_policy_t at location p to use policy - * AES_CM_128_HMAC_SHA1_32 as defined in - * draft-ietf-mmusic-sdescriptions-12.txt. This policy uses AES-128 - * Counter Mode encryption and HMAC-SHA1 authentication, with an - * authentication tag that is only 32 bits long. This length is - * considered adequate only for protecting audio and video media that - * use a stateless playback function. See Section 7.5 of RFC 3711 - * (http://www.ietf.org/rfc/rfc3711.txt). - * - * This function is a convenience that helps to avoid dealing directly - * with the policy data structure. You are encouraged to initialize - * policy elements with this function call. Doing so may allow your - * code to be forward compatible with later versions of libSRTP that - * include more elements in the crypto_policy_t datatype. - * - * @warning This crypto policy is intended for use in SRTP, but not in - * SRTCP. It is recommended that a policy that uses longer - * authentication tags be used for SRTCP. See Section 7.5 of RFC 3711 - * (http://www.ietf.org/rfc/rfc3711.txt). - * - * @return void. - * - */ - -void -crypto_policy_set_aes_cm_128_hmac_sha1_32(crypto_policy_t *p); - - - -/** - * @brief crypto_policy_set_aes_cm_128_null_auth() sets a crypto - * policy structure to an encryption-only policy - * - * @param p is a pointer to the policy structure to be set - * - * The function call crypto_policy_set_aes_cm_128_null_auth(&p) sets - * the crypto_policy_t at location p to use the SRTP default cipher - * (AES-128 Counter Mode), but to use no authentication method. This - * policy is NOT RECOMMENDED unless it is unavoidable; see Section 7.5 - * of RFC 3711 (http://www.ietf.org/rfc/rfc3711.txt). - * - * This function is a convenience that helps to avoid dealing directly - * with the policy data structure. You are encouraged to initialize - * policy elements with this function call. Doing so may allow your - * code to be forward compatible with later versions of libSRTP that - * include more elements in the crypto_policy_t datatype. - * - * @warning This policy is NOT RECOMMENDED for SRTP unless it is - * unavoidable, and it is NOT RECOMMENDED at all for SRTCP; see - * Section 7.5 of RFC 3711 (http://www.ietf.org/rfc/rfc3711.txt). - * - * @return void. - * - */ - -void -crypto_policy_set_aes_cm_128_null_auth(crypto_policy_t *p); - - -/** - * @brief crypto_policy_set_null_cipher_hmac_sha1_80() sets a crypto - * policy structure to an authentication-only policy - * - * @param p is a pointer to the policy structure to be set - * - * The function call crypto_policy_set_null_cipher_hmac_sha1_80(&p) - * sets the crypto_policy_t at location p to use HMAC-SHA1 with an 80 - * bit authentication tag to provide message authentication, but to - * use no encryption. This policy is NOT RECOMMENDED for SRTP unless - * there is a requirement to forego encryption. - * - * This function is a convenience that helps to avoid dealing directly - * with the policy data structure. You are encouraged to initialize - * policy elements with this function call. Doing so may allow your - * code to be forward compatible with later versions of libSRTP that - * include more elements in the crypto_policy_t datatype. - * - * @warning This policy is NOT RECOMMENDED for SRTP unless there is a - * requirement to forego encryption. - * - * @return void. - * - */ - -void -crypto_policy_set_null_cipher_hmac_sha1_80(crypto_policy_t *p); - -/** - * @brief srtp_dealloc() deallocates storage for an SRTP session - * context. - * - * The function call srtp_dealloc(s) deallocates storage for the - * SRTP session context s. This function should be called no more - * than one time for each of the contexts allocated by the function - * srtp_create(). - * - * @param s is the srtp_t for the session to be deallocated. - * - * @return - * - err_status_ok if there no problems. - * - err_status_dealloc_fail a memory deallocation failure occured. - */ - -err_status_t -srtp_dealloc(srtp_t s); - - -/* - * @brief identifies a particular SRTP profile - * - * An srtp_profile_t enumeration is used to identify a particular SRTP - * profile (that is, a set of algorithms and parameters). These - * profiles are defined in the DTLS-SRTP draft. - */ - -typedef enum { - srtp_profile_reserved = 0, - srtp_profile_aes128_cm_sha1_80 = 1, - srtp_profile_aes128_cm_sha1_32 = 2, - srtp_profile_aes256_cm_sha1_80 = 3, - srtp_profile_aes256_cm_sha1_32 = 4, - srtp_profile_null_sha1_80 = 5, - srtp_profile_null_sha1_32 = 6, -} srtp_profile_t; - - -/** - * @brief crypto_policy_set_from_profile_for_rtp() sets a crypto policy - * structure to the appropriate value for RTP based on an srtp_profile_t - * - * @param p is a pointer to the policy structure to be set - * - * The function call crypto_policy_set_rtp_default(&policy, profile) - * sets the crypto_policy_t at location policy to the policy for RTP - * protection, as defined by the srtp_profile_t profile. - * - * This function is a convenience that helps to avoid dealing directly - * with the policy data structure. You are encouraged to initialize - * policy elements with this function call. Doing so may allow your - * code to be forward compatible with later versions of libSRTP that - * include more elements in the crypto_policy_t datatype. - * - * @return values - * - err_status_ok no problems were encountered - * - err_status_bad_param the profile is not supported - * - */ -err_status_t -crypto_policy_set_from_profile_for_rtp(crypto_policy_t *policy, - srtp_profile_t profile); - - - - -/** - * @brief crypto_policy_set_from_profile_for_rtcp() sets a crypto policy - * structure to the appropriate value for RTCP based on an srtp_profile_t - * - * @param p is a pointer to the policy structure to be set - * - * The function call crypto_policy_set_rtcp_default(&policy, profile) - * sets the crypto_policy_t at location policy to the policy for RTCP - * protection, as defined by the srtp_profile_t profile. - * - * This function is a convenience that helps to avoid dealing directly - * with the policy data structure. You are encouraged to initialize - * policy elements with this function call. Doing so may allow your - * code to be forward compatible with later versions of libSRTP that - * include more elements in the crypto_policy_t datatype. - * - * @return values - * - err_status_ok no problems were encountered - * - err_status_bad_param the profile is not supported - * - */ -err_status_t -crypto_policy_set_from_profile_for_rtcp(crypto_policy_t *policy, - srtp_profile_t profile); - -/** - * @brief returns the master key length for a given SRTP profile - */ -unsigned int -srtp_profile_get_master_key_length(srtp_profile_t profile); - - -/** - * @brief returns the master salt length for a given SRTP profile - */ -unsigned int -srtp_profile_get_master_salt_length(srtp_profile_t profile); - -/** - * @brief appends the salt to the key - * - * The function call append_salt_to_key(k, klen, s, slen) - * copies the string s to the location at klen bytes following - * the location k. - * - * @warning There must be at least bytes_in_salt + bytes_in_key bytes - * available at the location pointed to by key. - * - */ - -void -append_salt_to_key(unsigned char *key, unsigned int bytes_in_key, - unsigned char *salt, unsigned int bytes_in_salt); - - - -/** - * @} - */ - - - -/** - * @defgroup SRTCP Secure RTCP - * @ingroup SRTP - * - * @brief Secure RTCP functions are used to protect RTCP traffic. - * - * RTCP is the control protocol for RTP. libSRTP protects RTCP - * traffic in much the same way as it does RTP traffic. The function - * srtp_protect_rtcp() applies cryptographic protections to outbound - * RTCP packets, and srtp_unprotect_rtcp() verifies the protections on - * inbound RTCP packets. - * - * A note on the naming convention: srtp_protect_rtcp() has an srtp_t - * as its first argument, and thus has `srtp_' as its prefix. The - * trailing `_rtcp' indicates the protocol on which it acts. - * - * @{ - */ - -/** - * @brief srtp_protect_rtcp() is the Secure RTCP sender-side packet - * processing function. - * - * The function call srtp_protect_rtcp(ctx, rtp_hdr, len_ptr) applies - * SRTCP protection to the RTCP packet rtcp_hdr (which has length - * *len_ptr) using the SRTP session context ctx. If err_status_ok is - * returned, then rtp_hdr points to the resulting SRTCP packet and - * *len_ptr is the number of octets in that packet; otherwise, no - * assumptions should be made about the value of either data elements. - * - * @warning This function assumes that it can write the authentication - * tag into the location in memory immediately following the RTCP - * packet, and assumes that the RTCP packet is aligned on a 32-bit - * boundary. - * - * @param ctx is the SRTP context to use in processing the packet. - * - * @param rtcp_hdr is a pointer to the RTCP packet (before the call); after - * the function returns, it points to the srtp packet. - * - * @param pkt_octet_len is a pointer to the length in octets of the - * complete RTCP packet (header and body) before the function call, - * and of the complete SRTCP packet after the call, if err_status_ok - * was returned. Otherwise, the value of the data to which it points - * is undefined. - * - * @return - * - err_status_ok if there were no problems. - * - [other] if there was a failure in - * the cryptographic mechanisms. - */ - - -err_status_t -srtp_protect_rtcp(srtp_t ctx, void *rtcp_hdr, int *pkt_octet_len); - -/** - * @brief srtp_unprotect_rtcp() is the Secure RTCP receiver-side packet - * processing function. - * - * The function call srtp_unprotect_rtcp(ctx, srtp_hdr, len_ptr) - * verifies the Secure RTCP protection of the SRTCP packet pointed to - * by srtcp_hdr (which has length *len_ptr), using the SRTP session - * context ctx. If err_status_ok is returned, then srtcp_hdr points - * to the resulting RTCP packet and *len_ptr is the number of octets - * in that packet; otherwise, no assumptions should be made about the - * value of either data elements. - * - * @warning This function assumes that the SRTCP packet is aligned on a - * 32-bit boundary. - * - * @param ctx is a pointer to the srtp_t which applies to the - * particular packet. - * - * @param srtcp_hdr is a pointer to the header of the SRTCP packet - * (before the call). After the function returns, it points to the - * rtp packet if err_status_ok was returned; otherwise, the value of - * the data to which it points is undefined. - * - * @param pkt_octet_len is a pointer to the length in octets of the - * complete SRTCP packet (header and body) before the function call, - * and of the complete rtp packet after the call, if err_status_ok was - * returned. Otherwise, the value of the data to which it points is - * undefined. - * - * @return - * - err_status_ok if the RTCP packet is valid. - * - err_status_auth_fail if the SRTCP packet failed the message - * authentication check. - * - err_status_replay_fail if the SRTCP packet is a replay (e.g. has - * already been processed and accepted). - * - [other] if there has been an error in the cryptographic mechanisms. - * - */ - -err_status_t -srtp_unprotect_rtcp(srtp_t ctx, void *srtcp_hdr, int *pkt_octet_len); - -/** - * @} - */ - -/** - * @defgroup SRTPevents SRTP events and callbacks - * @ingroup SRTP - * - * @brief libSRTP can use a user-provided callback function to - * handle events. - * - * - * libSRTP allows a user to provide a callback function to handle - * events that need to be dealt with outside of the data plane (see - * the enum srtp_event_t for a description of these events). Dealing - * with these events is not a strict necessity; they are not - * security-critical, but the application may suffer if they are not - * handled. The function srtp_set_event_handler() is used to provide - * the callback function. - * - * A default event handler that merely reports on the events as they - * happen is included. It is also possible to set the event handler - * function to NULL, in which case all events will just be silently - * ignored. - * - * @{ - */ - -/** - * @brief srtp_event_t defines events that need to be handled - * - * The enum srtp_event_t defines events that need to be handled - * outside the `data plane', such as SSRC collisions and - * key expirations. - * - * When a key expires or the maximum number of packets has been - * reached, an SRTP stream will enter an `expired' state in which no - * more packets can be protected or unprotected. When this happens, - * it is likely that you will want to either deallocate the stream - * (using srtp_stream_dealloc()), and possibly allocate a new one. - * - * When an SRTP stream expires, the other streams in the same session - * are unaffected, unless key sharing is used by that stream. In the - * latter case, all of the streams in the session will expire. - */ - -typedef enum { - event_ssrc_collision, /**< - * An SSRC collision occured. - */ - event_key_soft_limit, /**< An SRTP stream reached the soft key - * usage limit and will expire soon. - */ - event_key_hard_limit, /**< An SRTP stream reached the hard - * key usage limit and has expired. - */ - event_packet_index_limit /**< An SRTP stream reached the hard - * packet limit (2^48 packets). - */ -} srtp_event_t; - -/** - * @brief srtp_event_data_t is the structure passed as a callback to - * the event handler function - * - * The struct srtp_event_data_t holds the data passed to the event - * handler function. - */ - -typedef struct srtp_event_data_t { - srtp_t session; /**< The session in which the event happend. */ - srtp_stream_t stream; /**< The stream in which the event happend. */ - srtp_event_t event; /**< An enum indicating the type of event. */ -} srtp_event_data_t; - -/** - * @brief srtp_event_handler_func_t is the function prototype for - * the event handler. - * - * The typedef srtp_event_handler_func_t is the prototype for the - * event handler function. It has as its only argument an - * srtp_event_data_t which describes the event that needs to be handled. - * There can only be a single, global handler for all events in - * libSRTP. - */ - -typedef void (srtp_event_handler_func_t)(srtp_event_data_t *data); - -/** - * @brief sets the event handler to the function supplied by the caller. - * - * The function call srtp_install_event_handler(func) sets the event - * handler function to the value func. The value NULL is acceptable - * as an argument; in this case, events will be ignored rather than - * handled. - * - * @param func is a pointer to a fuction that takes an srtp_event_data_t - * pointer as an argument and returns void. This function - * will be used by libSRTP to handle events. - */ - -err_status_t -srtp_install_event_handler(srtp_event_handler_func_t func); - -/** - * @} - */ -/* in host order, so outside the #if */ -#define SRTCP_E_BIT 0x80000000 -/* for byte-access */ -#define SRTCP_E_BYTE_BIT 0x80 -#define SRTCP_INDEX_MASK 0x7fffffff - -#ifdef __cplusplus -} -#endif - -#endif /* SRTP_H */ |