diff options
Diffstat (limited to 'netwerk/srtp/src/include/srtp.h')
| -rw-r--r-- | netwerk/srtp/src/include/srtp.h | 1759 |
1 files changed, 1759 insertions, 0 deletions
diff --git a/netwerk/srtp/src/include/srtp.h b/netwerk/srtp/src/include/srtp.h new file mode 100644 index 0000000000..1fdd6c3aff --- /dev/null +++ b/netwerk/srtp/src/include/srtp.h @@ -0,0 +1,1759 @@ +/* + * srtp.h + * + * interface to 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_SRTP_H +#define SRTP_SRTP_H + +#include <stdint.h> + +#ifdef __cplusplus +extern "C" { +#endif + +/** + * @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 16 + +/** + * SRTP_MAX_MKI_LEN is the maximum size the MKI could be which is + * 128 bytes + */ +#define SRTP_MAX_MKI_LEN 128 + +/** + * SRTP_MAX_TRAILER_LEN is the maximum length of the SRTP trailer + * (authentication tag and MKI) supported by libSRTP. This value is + * the maixmum 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 + SRTP_MAX_MKI_LEN) + +/** + * SRTP_MAX_NUM_MASTER_KEYS is the maximum number of Master keys for + * MKI supported by libSRTP. + * + */ +#define SRTP_MAX_NUM_MASTER_KEYS 16 + +#define SRTP_SALT_LEN 14 + +/* + * SRTP_AEAD_SALT_LEN is the length of the SALT values used with + * GCM mode. GCM mode requires an IV. The SALT value is used + * as part of the IV formation logic applied to each RTP packet. + */ +#define SRTP_AEAD_SALT_LEN 12 + +#define SRTP_AES_128_KEY_LEN 16 +#define SRTP_AES_192_KEY_LEN 24 +#define SRTP_AES_256_KEY_LEN 32 + +#define SRTP_AES_ICM_128_KEY_LEN_WSALT (SRTP_SALT_LEN + SRTP_AES_128_KEY_LEN) +#define SRTP_AES_ICM_192_KEY_LEN_WSALT (SRTP_SALT_LEN + SRTP_AES_192_KEY_LEN) +#define SRTP_AES_ICM_256_KEY_LEN_WSALT (SRTP_SALT_LEN + SRTP_AES_256_KEY_LEN) + +#define SRTP_AES_GCM_128_KEY_LEN_WSALT \ + (SRTP_AEAD_SALT_LEN + SRTP_AES_128_KEY_LEN) +#define SRTP_AES_GCM_192_KEY_LEN_WSALT \ + (SRTP_AEAD_SALT_LEN + SRTP_AES_192_KEY_LEN) +#define SRTP_AES_GCM_256_KEY_LEN_WSALT \ + (SRTP_AEAD_SALT_LEN + SRTP_AES_256_KEY_LEN) + +/** + * @brief A srtp_cipher_type_id_t is an identifier for a particular cipher + * type. + * + * A srtp_cipher_type_id_t is an integer that represents a particular + * cipher type, e.g. the Advanced Encryption Standard (AES). A + * SRTP_NULL_CIPHER is avaliable; this cipher leaves the data unchanged, + * and can be selected to indicate that no encryption is to take + * place. + * + * @ingroup Ciphers + */ +typedef uint32_t srtp_cipher_type_id_t; + +/** + * @brief An srtp_auth_type_id_t is an identifier for a particular + * authentication + * function. + * + * An srtp_auth_type_id_t is an integer that represents a particular + * authentication function type, e.g. HMAC-SHA1. A SRTP_NULL_AUTH is + * avaliable; this authentication function performs no computation, + * and can be selected to indicate that no authentication is to take + * place. + * + * @ingroup Authentication + */ +typedef uint32_t srtp_auth_type_id_t; + +/** + * @brief srtp_err_status_t defines error codes. + * + * The enumeration srtp_err_status_t defines error codes. Note that the + * value of srtp_err_status_ok is equal to zero, which can simplify error + * checking somewhat. + * + */ +typedef enum { + srtp_err_status_ok = 0, /**< nothing to report */ + srtp_err_status_fail = 1, /**< unspecified failure */ + srtp_err_status_bad_param = 2, /**< unsupported parameter */ + srtp_err_status_alloc_fail = 3, /**< couldn't allocate memory */ + srtp_err_status_dealloc_fail = 4, /**< couldn't deallocate properly */ + srtp_err_status_init_fail = 5, /**< couldn't initialize */ + srtp_err_status_terminus = 6, /**< can't process as much data as */ + /**< requested */ + srtp_err_status_auth_fail = 7, /**< authentication failure */ + srtp_err_status_cipher_fail = 8, /**< cipher failure */ + srtp_err_status_replay_fail = 9, /**< replay check failed (bad index) */ + srtp_err_status_replay_old = 10, /**< replay check failed (index too */ + /**< old) */ + srtp_err_status_algo_fail = 11, /**< algorithm failed test routine */ + srtp_err_status_no_such_op = 12, /**< unsupported operation */ + srtp_err_status_no_ctx = 13, /**< no appropriate context found */ + srtp_err_status_cant_check = 14, /**< unable to perform desired */ + /**< validation */ + srtp_err_status_key_expired = 15, /**< can't use key any more */ + srtp_err_status_socket_err = 16, /**< error in use of socket */ + srtp_err_status_signal_err = 17, /**< error in use POSIX signals */ + srtp_err_status_nonce_bad = 18, /**< nonce check failed */ + srtp_err_status_read_fail = 19, /**< couldn't read data */ + srtp_err_status_write_fail = 20, /**< couldn't write data */ + srtp_err_status_parse_err = 21, /**< error parsing data */ + srtp_err_status_encode_err = 22, /**< error encoding data */ + srtp_err_status_semaphore_err = 23, /**< error while using semaphores */ + srtp_err_status_pfkey_err = 24, /**< error while using pfkey */ + srtp_err_status_bad_mki = 25, /**< error MKI present in packet is */ + /**< invalid */ + srtp_err_status_pkt_idx_old = 26, /**< packet index is too old to */ + /**< consider */ + srtp_err_status_pkt_idx_adv = 27 /**< packet index advanced, reset */ + /**< needed */ +} srtp_err_status_t; + +typedef struct srtp_ctx_t_ srtp_ctx_t; + +/** + * @brief srtp_sec_serv_t describes a set of security services. + * + * A srtp_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 */ +} srtp_sec_serv_t; + +/** + * @brief srtp_crypto_policy_t describes a particular crypto policy that + * can be applied to an SRTP stream. + * + * A srtp_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 srtp_crypto_policy_t { + srtp_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. */ + srtp_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. */ + srtp_sec_serv_t sec_serv; /**< The flag indicating the security */ + /**< services to be applied. */ +} srtp_crypto_policy_t; + +/** + * @brief srtp_ssrc_type_t describes the type of an SSRC. + * + * An srtp_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()) */ +} srtp_ssrc_type_t; + +/** + * @brief An srtp_ssrc_t represents a particular SSRC value, or a `wildcard' + * SSRC. + * + * An srtp_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 { + srtp_ssrc_type_t type; /**< The type of this particular SSRC */ + unsigned int value; /**< The value of this SSRC, if it is not a */ + /**< wildcard */ +} srtp_ssrc_t; + +/** + * @brief points to an EKT policy + */ +typedef struct srtp_ekt_policy_ctx_t *srtp_ekt_policy_t; + +/** + * @brief points to EKT stream data + */ +typedef struct srtp_ekt_stream_ctx_t *srtp_ekt_stream_t; + +/** + * @brief srtp_master_key_t represents a master key. There will + * be a Master Key Index and the Master Key associated with the + * Master Key Index. Need to also keep track of the Master Key + * Index Size to correctly read it from a packet. + */ +typedef struct srtp_master_key_t { + unsigned char *key; + unsigned char *mki_id; + unsigned int mki_size; +} srtp_master_key_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 { + srtp_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. */ + srtp_crypto_policy_t rtp; /**< SRTP crypto policy. */ + srtp_crypto_policy_t rtcp; /**< SRTCP crypto policy. */ + unsigned char *key; /**< Pointer to the SRTP master key for */ + /**< this stream. */ + srtp_master_key_t **keys; /** Array of Master Key structures */ + unsigned long num_master_keys; /** Number of master keys */ + srtp_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!) */ + int *enc_xtn_hdr; /**< List of header ids to encrypt. */ + int enc_xtn_hdr_count; /**< Number of entries in list of header */ + /**< ids. */ + 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 srtp_ctx_t *srtp_t; + +/** + * @brief srtp_init() initializes the srtp library. + * + * @warning This function @b must be called before any other srtp + * functions. + */ +srtp_err_status_t srtp_init(void); + +/** + * @brief srtp_shutdown() de-initializes the srtp library. + * + * @warning No srtp functions may be called after calling this function. + */ +srtp_err_status_t srtp_shutdown(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 srtp_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. + * + * @warning This function assumes that it can write SRTP_MAX_TRAILER_LEN + * into the location in memory immediately following the RTP packet. + * Callers MUST ensure that this much writable memory is available in + * the buffer that holds the RTP packet. + * + * @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 srtp_err_status_ok was returned. + * Otherwise, the value of the data to which it points is undefined. + * + * @return + * - srtp_err_status_ok no problems + * - srtp_err_status_replay_fail rtp sequence number was non-increasing + * - @e other failure in cryptographic mechanisms + */ +srtp_err_status_t srtp_protect(srtp_t ctx, void *rtp_hdr, int *len_ptr); + +/** + * @brief srtp_protect_mki() is the Secure RTP sender-side packet processing + * function that can utilize MKI. + * + * 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 srtp_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. + * + * @warning This function assumes that it can write SRTP_MAX_TRAILER_LEN + * into the location in memory immediately following the RTP packet. + * Callers MUST ensure that this much writable memory is available in + * the buffer that holds the RTP packet. + * + * @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 pkt_octet_len 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 srtp_err_status_ok was returned. + * Otherwise, the value of the data to which it points is undefined. + * + * @param use_mki is a boolean to tell the system if mki is being used. If + * set to false then will use the first set of session keys. If set to true + * will + * use the session keys identified by the mki_index + * + * @param mki_index integer value specifying which set of session keys should be + * used if use_mki is set to true. + * + * @return + * - srtp_err_status_ok no problems + * - srtp_err_status_replay_fail rtp sequence number was non-increasing + * - @e other failure in cryptographic mechanisms + */ +srtp_err_status_t srtp_protect_mki(srtp_ctx_t *ctx, + void *rtp_hdr, + int *pkt_octet_len, + unsigned int use_mki, + unsigned int mki_index); + +/** + * @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 + * srtp_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 the SRTP session 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 srtp_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 srtp_err_status_ok was returned. + * Otherwise, the value of the data to which it points is undefined. + * + * @return + * - srtp_err_status_ok if the RTP packet is valid. + * - srtp_err_status_auth_fail if the SRTP packet failed the message + * authentication check. + * - srtp_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. + * + */ +srtp_err_status_t srtp_unprotect(srtp_t ctx, void *srtp_hdr, int *len_ptr); + +/** + * @brief srtp_unprotect_mki() is the Secure RTP receiver-side packet + * processing function that checks for MKI. + * + * 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 + * srtp_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 the SRTP session 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 srtp_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 srtp_err_status_ok was returned. + * Otherwise, the value of the data to which it points is undefined. + * + * @param use_mki is a boolean to tell the system if mki is being used. If + * set to false then will use the first set of session keys. If set to true + * will + * use the session keys identified by the mki_index + * + * @return + * - srtp_err_status_ok if the RTP packet is valid. + * - srtp_err_status_auth_fail if the SRTP packet failed the message + * authentication check. + * - srtp_err_status_replay_fail if the SRTP packet is a replay (e.g. packet + * has already been processed and accepted). + * - srtp_err_status_bad_mki if the MKI in the packet is not a known MKI id + * - [other] if there has been an error in the cryptographic mechanisms. + * + */ +srtp_err_status_t srtp_unprotect_mki(srtp_t ctx, + void *srtp_hdr, + int *len_ptr, + unsigned int use_mki); + +/** + * @brief srtp_create() allocates and initializes an SRTP session. + + * The function call srtp_create(session, policy) allocates and + * initializes an SRTP session context, applying the given policy. + * + * @param session is a pointer to 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 + * - srtp_err_status_ok if creation succeded. + * - srtp_err_status_alloc_fail if allocation failed. + * - srtp_err_status_init_fail if initialization failed. + */ +srtp_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: + * - srtp_err_status_ok if stream creation succeded. + * - srtp_err_status_alloc_fail if stream allocation failed + * - srtp_err_status_init_fail if stream initialization failed. + */ +srtp_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 + * in network byte order. + * + * @warning Wildcard SSRC values cannot be removed from a + * session. + * + * @return + * - srtp_err_status_ok if the stream deallocation succeded. + * - [other] otherwise. + * + */ +srtp_err_status_t srtp_remove_stream(srtp_t session, unsigned int ssrc); + +/** + * @brief srtp_update() udpates all streams in the session. + * + * The function call srtp_update(session, policy) updates + * all the streams in the session applying the given policy + * and key. The exsisting ROC value of all streams will be + * preserved. + * + * @param session is the SRTP session that contains the streams + * to be updated. + * + * @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. The final element of the list @b must + * have its `next' field set to NULL. + * + * @return + * - srtp_err_status_ok if stream creation succeded. + * - srtp_err_status_alloc_fail if stream allocation failed + * - srtp_err_status_init_fail if stream initialization failed. + * - [other] otherwise. + * + */ +srtp_err_status_t srtp_update(srtp_t session, const srtp_policy_t *policy); + +/** + * @brief srtp_update_stream() udpates a SRTP stream. + * + * The function call srtp_update_stream(session, policy) updates + * the stream(s) in the session that match applying the given + * policy and key. The exsisting ROC value of all stream(s) will + * be preserved. + * + * @param session is the SRTP session that contains the streams + * to be updated. + * + * @param policy is the srtp_policy_t struct that describes the policy + * for the session. + * + * @return + * - srtp_err_status_ok if stream creation succeded. + * - srtp_err_status_alloc_fail if stream allocation failed + * - srtp_err_status_init_fail if stream initialization failed. + * - [other] otherwise. + * + */ +srtp_err_status_t srtp_update_stream(srtp_t session, + const srtp_policy_t *policy); + +/** + * @brief srtp_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 srtp_crypto_policy_set_rtp_default(srtp_crypto_policy_t *p); + +/** + * @brief srtp_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 srtp_crypto_policy_set_rtcp_default(&p) sets the + * srtp_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 srtp_crypto_policy_t datatype. + * + * @return void. + * + */ +void srtp_crypto_policy_set_rtcp_default(srtp_crypto_policy_t *p); + +/** + * @brief srtp_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 srtp_crypto_policy_set_aes_cm_128_hmac_sha1_80() is a + * synonym for srtp_crypto_policy_set_rtp_default(). It conforms to the + * naming convention used in RFC 4568 (SDP Security Descriptions for + * Media Streams). + * + * @return void. + * + */ +#define srtp_crypto_policy_set_aes_cm_128_hmac_sha1_80(p) \ + srtp_crypto_policy_set_rtp_default(p) + +/** + * @brief srtp_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 srtp_crypto_policy_set_aes_cm_128_hmac_sha1_32(&p) + * sets the srtp_crypto_policy_t at location p to use policy + * AES_CM_128_HMAC_SHA1_32 as defined in RFC 4568. + * 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 srtp_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 srtp_crypto_policy_set_aes_cm_128_hmac_sha1_32(srtp_crypto_policy_t *p); + +/** + * @brief srtp_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 srtp_crypto_policy_set_aes_cm_128_null_auth(&p) sets + * the srtp_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 srtp_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 srtp_crypto_policy_set_aes_cm_128_null_auth(srtp_crypto_policy_t *p); + +/** + * @brief srtp_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 srtp_crypto_policy_set_null_cipher_hmac_sha1_80(&p) + * sets the srtp_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 srtp_crypto_policy_t datatype. + * + * @warning This policy is NOT RECOMMENDED for SRTP unless there is a + * requirement to forego encryption. + * + * @return void. + * + */ +void srtp_crypto_policy_set_null_cipher_hmac_sha1_80(srtp_crypto_policy_t *p); + +/** + * @brief srtp_crypto_policy_set_null_cipher_hmac_null() sets a crypto + * policy structure to use no encryption or authentication. + * + * @param p is a pointer to the policy structure to be set + * + * The function call srtp_crypto_policy_set_null_cipher_hmac_null(&p) + * sets the srtp_crypto_policy_t at location p to use no encryption and + * no authentication. This policy should only be used for testing and + * troubleshootingl. + * + * 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 srtp_crypto_policy_t datatype. + * + * @warning This policy is NOT RECOMMENDED for SRTP unless there is a + * requirement to forego encryption and authentication. + * + * @return void. + * + */ +void srtp_crypto_policy_set_null_cipher_hmac_null(srtp_crypto_policy_t *p); + +/** + * @brief srtp_crypto_policy_set_aes_cm_256_hmac_sha1_80() sets a crypto + * policy structure to a encryption and authentication policy using AES-256 + * for RTP protection. + * + * @param p is a pointer to the policy structure to be set + * + * The function call srtp_crypto_policy_set_aes_cm_256_hmac_sha1_80(&p) + * sets the srtp_crypto_policy_t at location p to use policy + * AES_CM_256_HMAC_SHA1_80 as defined in RFC 6188. This policy uses AES-256 + * Counter Mode encryption and HMAC-SHA1 authentication, with an 80 bit + * authentication tag. + * + * 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 srtp_crypto_policy_t datatype. + * + * @return void. + * + */ +void srtp_crypto_policy_set_aes_cm_256_hmac_sha1_80(srtp_crypto_policy_t *p); + +/** + * @brief srtp_crypto_policy_set_aes_cm_256_hmac_sha1_32() sets a crypto + * policy structure to a short-authentication tag policy using AES-256 + * encryption. + * + * @param p is a pointer to the policy structure to be set + * + * The function call srtp_crypto_policy_set_aes_cm_256_hmac_sha1_32(&p) + * sets the srtp_crypto_policy_t at location p to use policy + * AES_CM_256_HMAC_SHA1_32 as defined in RFC 6188. This policy uses AES-256 + * 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 srtp_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 srtp_crypto_policy_set_aes_cm_256_hmac_sha1_32(srtp_crypto_policy_t *p); + +/** + * @brief srtp_crypto_policy_set_aes_cm_256_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 srtp_crypto_policy_set_aes_cm_256_null_auth(&p) sets + * the srtp_crypto_policy_t at location p to use the SRTP default cipher + * (AES-256 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 srtp_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 srtp_crypto_policy_set_aes_cm_256_null_auth(srtp_crypto_policy_t *p); + +/** + * @brief srtp_crypto_policy_set_aes_cm_192_hmac_sha1_80() sets a crypto + * policy structure to a encryption and authentication policy using AES-192 + * for RTP protection. + * + * @param p is a pointer to the policy structure to be set + * + * The function call srtp_crypto_policy_set_aes_cm_192_hmac_sha1_80(&p) + * sets the crypto_policy_t at location p to use policy + * AES_CM_192_HMAC_SHA1_80 as defined in RFC 6188. This policy uses AES-192 + * Counter Mode encryption and HMAC-SHA1 authentication, with an 80 bit + * authentication tag. + * + * 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 srtp_crypto_policy_set_aes_cm_192_hmac_sha1_80(srtp_crypto_policy_t *p); + +/** + * @brief srtp_crypto_policy_set_aes_cm_192_hmac_sha1_32() sets a crypto + * policy structure to a short-authentication tag policy using AES-192 + * encryption. + * + * @param p is a pointer to the policy structure to be set + * + * The function call srtp_crypto_policy_set_aes_cm_192_hmac_sha1_32(&p) + * sets the crypto_policy_t at location p to use policy + * AES_CM_192_HMAC_SHA1_32 as defined in RFC 6188. This policy uses AES-192 + * 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 srtp_crypto_policy_set_aes_cm_192_hmac_sha1_32(srtp_crypto_policy_t *p); + +/** + * @brief srtp_crypto_policy_set_aes_cm_192_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 srtp_crypto_policy_set_aes_cm_192_null_auth(&p) sets + * the crypto_policy_t at location p to use the SRTP default cipher + * (AES-192 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 srtp_crypto_policy_set_aes_cm_192_null_auth(srtp_crypto_policy_t *p); + +/** + * @brief srtp_crypto_policy_set_aes_gcm_128_8_auth() sets a crypto + * policy structure to an AEAD encryption policy. + * + * @param p is a pointer to the policy structure to be set + * + * The function call srtp_crypto_policy_set_aes_gcm_128_8_auth(&p) sets + * the srtp_crypto_policy_t at location p to use the SRTP default cipher + * (AES-128 Galois Counter Mode) with 8 octet auth tag. This + * policy applies confidentiality and authentication to both the + * RTP and RTCP packets. + * + * 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 srtp_crypto_policy_t datatype. + * + * @return void. + * + */ +void srtp_crypto_policy_set_aes_gcm_128_8_auth(srtp_crypto_policy_t *p); + +/** + * @brief srtp_crypto_policy_set_aes_gcm_256_8_auth() sets a crypto + * policy structure to an AEAD encryption policy + * + * @param p is a pointer to the policy structure to be set + * + * The function call srtp_crypto_policy_set_aes_gcm_256_8_auth(&p) sets + * the srtp_crypto_policy_t at location p to use the SRTP default cipher + * (AES-256 Galois Counter Mode) with 8 octet auth tag. This + * policy applies confidentiality and authentication to both the + * RTP and RTCP packets. + * + * 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 srtp_crypto_policy_t datatype. + * + * @return void. + * + */ +void srtp_crypto_policy_set_aes_gcm_256_8_auth(srtp_crypto_policy_t *p); + +/** + * @brief srtp_crypto_policy_set_aes_gcm_128_8_only_auth() sets a crypto + * policy structure to an AEAD authentication-only policy + * + * @param p is a pointer to the policy structure to be set + * + * The function call srtp_crypto_policy_set_aes_gcm_128_8_only_auth(&p) sets + * the srtp_crypto_policy_t at location p to use the SRTP default cipher + * (AES-128 Galois Counter Mode) with 8 octet auth tag. This policy + * applies confidentiality and authentication to the RTP packets, + * but only authentication to the RTCP packets. + * + * 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 srtp_crypto_policy_t datatype. + * + * @return void. + * + */ +void srtp_crypto_policy_set_aes_gcm_128_8_only_auth(srtp_crypto_policy_t *p); + +/** + * @brief srtp_crypto_policy_set_aes_gcm_256_8_only_auth() sets a crypto + * policy structure to an AEAD authentication-only policy + * + * @param p is a pointer to the policy structure to be set + * + * The function call srtp_crypto_policy_set_aes_gcm_256_8_only_auth(&p) sets + * the srtp_crypto_policy_t at location p to use the SRTP default cipher + * (AES-256 Galois Counter Mode) with 8 octet auth tag. This policy + * applies confidentiality and authentication to the RTP packets, + * but only authentication to the RTCP packets. + * + * 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 srtp_crypto_policy_t datatype. + * + * @return void. + * + */ +void srtp_crypto_policy_set_aes_gcm_256_8_only_auth(srtp_crypto_policy_t *p); + +/** + * @brief srtp_crypto_policy_set_aes_gcm_128_16_auth() sets a crypto + * policy structure to an AEAD encryption policy. + * + * @param p is a pointer to the policy structure to be set + * + * The function call srtp_crypto_policy_set_aes_gcm_128_16_auth(&p) sets + * the srtp_crypto_policy_t at location p to use the SRTP default cipher + * (AES-128 Galois Counter Mode) with 16 octet auth tag. This + * policy applies confidentiality and authentication to both the + * RTP and RTCP packets. + * + * 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 srtp_crypto_policy_t datatype. + * + * @return void. + * + */ +void srtp_crypto_policy_set_aes_gcm_128_16_auth(srtp_crypto_policy_t *p); + +/** + * @brief srtp_crypto_policy_set_aes_gcm_256_16_auth() sets a crypto + * policy structure to an AEAD encryption policy + * + * @param p is a pointer to the policy structure to be set + * + * The function call srtp_crypto_policy_set_aes_gcm_256_16_auth(&p) sets + * the srtp_crypto_policy_t at location p to use the SRTP default cipher + * (AES-256 Galois Counter Mode) with 16 octet auth tag. This + * policy applies confidentiality and authentication to both the + * RTP and RTCP packets. + * + * 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 srtp_crypto_policy_t datatype. + * + * @return void. + * + */ +void srtp_crypto_policy_set_aes_gcm_256_16_auth(srtp_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 + * - srtp_err_status_ok if there no problems. + * - srtp_err_status_dealloc_fail a memory deallocation failure occured. + */ +srtp_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 for DTLS-SRTP: + * https://www.iana.org/assignments/srtp-protection/srtp-protection.xhtml + */ +typedef enum { + srtp_profile_reserved = 0, + srtp_profile_aes128_cm_sha1_80 = 1, + srtp_profile_aes128_cm_sha1_32 = 2, + srtp_profile_null_sha1_80 = 5, + srtp_profile_null_sha1_32 = 6, + srtp_profile_aead_aes_128_gcm = 7, + srtp_profile_aead_aes_256_gcm = 8, +} srtp_profile_t; + +/** + * @brief srtp_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 policy is a pointer to the policy structure to be set + * + * @param profile is an enumeration for the policy to be set + * + * The function call srtp_crypto_policy_set_rtp_default(&policy, profile) + * sets the srtp_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 srtp_crypto_policy_t datatype. + * + * @return values + * - srtp_err_status_ok no problems were encountered + * - srtp_err_status_bad_param the profile is not supported + * + */ +srtp_err_status_t srtp_crypto_policy_set_from_profile_for_rtp( + srtp_crypto_policy_t *policy, + srtp_profile_t profile); + +/** + * @brief srtp_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 policy is a pointer to the policy structure to be set + * + * @param profile is an enumeration for the policy to be set + * + * The function call srtp_crypto_policy_set_rtcp_default(&policy, profile) + * sets the srtp_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 srtp_crypto_policy_t datatype. + * + * @return values + * - srtp_err_status_ok no problems were encountered + * - srtp_err_status_bad_param the profile is not supported + * + */ +srtp_err_status_t srtp_crypto_policy_set_from_profile_for_rtcp( + srtp_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 srtp_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 srtp_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 srtp_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. + * + * @warning This function assumes that it can write SRTP_MAX_TRAILER_LEN+4 + * into the location in memory immediately following the RTCP packet. + * Callers MUST ensure that this much writable memory is available in + * the buffer that holds the RTCP packet. + * + * @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 srtp_err_status_ok + * was returned. Otherwise, the value of the data to which it points + * is undefined. + * + * @return + * - srtp_err_status_ok if there were no problems. + * - [other] if there was a failure in + * the cryptographic mechanisms. + */ +srtp_err_status_t srtp_protect_rtcp(srtp_t ctx, + void *rtcp_hdr, + int *pkt_octet_len); + +/** + * @brief srtp_protect_rtcp_mki() is the Secure RTCP sender-side packet + * processing function that can utilize mki. + * + * 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 srtp_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. + * + * @warning This function assumes that it can write SRTP_MAX_TRAILER_LEN+4 + * into the location in memory immediately following the RTCP packet. + * Callers MUST ensure that this much writable memory is available in + * the buffer that holds the RTCP packet. + * + * @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 srtp_err_status_ok + * was returned. Otherwise, the value of the data to which it points + * is undefined. + * + * @param use_mki is a boolean to tell the system if mki is being used. If + * set to false then will use the first set of session keys. If set to true + * will + * use the session keys identified by the mki_index + * + * @param mki_index integer value specifying which set of session kesy should be + * used if use_mki is set to true. + * + * @return + * - srtp_err_status_ok if there were no problems. + * - [other] if there was a failure in + * the cryptographic mechanisms. + */ +srtp_err_status_t srtp_protect_rtcp_mki(srtp_t ctx, + void *rtcp_hdr, + int *pkt_octet_len, + unsigned int use_mki, + unsigned int mki_index); + +/** + * @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 srtp_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 srtp_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 srtp_err_status_ok was + * returned. Otherwise, the value of the data to which it points is + * undefined. + * + * @return + * - srtp_err_status_ok if the RTCP packet is valid. + * - srtp_err_status_auth_fail if the SRTCP packet failed the message + * authentication check. + * - srtp_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. + * + */ +srtp_err_status_t srtp_unprotect_rtcp(srtp_t ctx, + void *srtcp_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 srtp_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 srtp_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 srtp_err_status_ok was + * returned. Otherwise, the value of the data to which it points is + * undefined. + * + * @param use_mki is a boolean to tell the system if mki is being used. If + * set to false then will use the first set of session keys. If set to true + * will use the session keys identified by the mki_index + * + * @return + * - srtp_err_status_ok if the RTCP packet is valid. + * - srtp_err_status_auth_fail if the SRTCP packet failed the message + * authentication check. + * - srtp_err_status_replay_fail if the SRTCP packet is a replay (e.g. has + * already been processed and accepted). + * - srtp_err_status_bad_mki if the MKI in the packet is not a known MKI + * id + * - [other] if there has been an error in the + * cryptographic mechanisms. + * + */ +srtp_err_status_t srtp_unprotect_rtcp_mki(srtp_t ctx, + void *srtcp_hdr, + int *pkt_octet_len, + unsigned int use_mki); + +/** + * @} + */ + +/** + * @defgroup User data associated to a SRTP session. + * @ingroup SRTP + * + * @brief Store custom user data within a SRTP session. + * + * @{ + */ + +/** + * @brief srtp_set_user_data() stores the given pointer into the SRTP + * session for later retrieval. + * + * @param ctx is the srtp_t context in which the given data pointer is + * stored. + * + * @param data is a pointer to the custom information (struct, function, + * etc) associated with the SRTP session. + * + * @return void. + * + */ +void srtp_set_user_data(srtp_t ctx, void *data); + +/** + * @brief srtp_get_user_data() retrieves the pointer to the custom data + * previously stored with srtp_set_user_data(). + * + * This function is mostly useful for retrieving data associated to a + * SRTP session when an event fires. The user can then get such a custom + * data by calling this function with the session field of the + * srtp_event_data_t struct as argument. + * + * @param ctx is the srtp_t context in which the given data pointer was + * stored. + * + * @return void* pointer to the user data. + * + */ +void *srtp_get_user_data(srtp_t ctx); + +/** + * @} + */ + +/** + * @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_remove_stream()), 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. */ + uint32_t ssrc; /**< The ssrc in host order of 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. + */ +srtp_err_status_t srtp_install_event_handler(srtp_event_handler_func_t func); + +/** + * @brief Returns the version string of the library. + * + */ +const char *srtp_get_version_string(void); + +/** + * @brief Returns the numeric representation of the library version. + * + */ +unsigned int srtp_get_version(void); + +/** + * @brief srtp_set_debug_module(mod_name, v) + * + * sets dynamic debugging to the value v (0 for off, 1 for on) for the + * debug module with the name mod_name + * + * returns err_status_ok on success, err_status_fail otherwise + */ +srtp_err_status_t srtp_set_debug_module(const char *mod_name, int v); + +/** + * @brief srtp_list_debug_modules() outputs a list of debugging modules + * + */ +srtp_err_status_t srtp_list_debug_modules(void); + +/** + * @brief srtp_log_level_t defines log levels. + * + * The enumeration srtp_log_level_t defines log levels reported + * in the srtp_log_handler_func_t. + * + */ +typedef enum { + srtp_log_level_error, /**< log level is reporting an error message */ + srtp_log_level_warning, /**< log level is reporting a warning message */ + srtp_log_level_info, /**< log level is reporting an info message */ + srtp_log_level_debug /**< log level is reporting a debug message */ +} srtp_log_level_t; + +/** + * @brief srtp_log_handler_func_t is the function prototype for + * the log handler. + * + * The typedef srtp_event_handler_func_t is the prototype for the + * event handler function. It has as srtp_log_level_t, log + * message and data as arguments. + * There can only be a single, global handler for all log messages in + * libSRTP. + */ +typedef void(srtp_log_handler_func_t)(srtp_log_level_t level, + const char *msg, + void *data); + +/** + * @brief sets the log handler to the function supplied by the caller. + * + * The function call srtp_install_log_handler(func) sets the log + * handler function to the value func. The value NULL is acceptable + * as an argument; in this case, log messages will be ignored. + * This function can be called before srtp_init() inorder to capture + * any logging during start up. + * + * @param func is a pointer to a fuction of type srtp_log_handler_func_t. + * This function will be used by libSRTP to output log messages. + * @param data is a user pointer that will be returned as the data argument in + * func. + */ +srtp_err_status_t srtp_install_log_handler(srtp_log_handler_func_t func, + void *data); + +/** + * @brief srtp_get_protect_trailer_length(session, use_mki, mki_index, length) + * + * Determines the length of the amount of data Lib SRTP will add to the + * packet during the protect process. The length is returned in the length + * parameter + * + * returns err_status_ok on success, err_status_bad_mki if the MKI index is + * invalid + * + */ +srtp_err_status_t srtp_get_protect_trailer_length(srtp_t session, + uint32_t use_mki, + uint32_t mki_index, + uint32_t *length); + +/** + * @brief srtp_get_protect_rtcp_trailer_length(session, use_mki, mki_index, + * length) + * + * Determines the length of the amount of data Lib SRTP will add to the + * packet during the protect process. The length is returned in the length + * parameter + * + * returns err_status_ok on success, err_status_bad_mki if the MKI index is + * invalid + * + */ +srtp_err_status_t srtp_get_protect_rtcp_trailer_length(srtp_t session, + uint32_t use_mki, + uint32_t mki_index, + uint32_t *length); + +/** + * @brief srtp_set_stream_roc(session, ssrc, roc) + * + * Set the roll-over-counter on a session for a given SSRC + * + * returns err_status_ok on success, srtp_err_status_bad_param if there is no + * stream found + * + */ +srtp_err_status_t srtp_set_stream_roc(srtp_t session, + uint32_t ssrc, + uint32_t roc); + +/** + * @brief srtp_get_stream_roc(session, ssrc, roc) + * + * Get the roll-over-counter on a session for a given SSRC + * + * returns err_status_ok on success, srtp_err_status_bad_param if there is no + * stream found + * + */ +srtp_err_status_t srtp_get_stream_roc(srtp_t session, + uint32_t ssrc, + uint32_t *roc); + +/** + * @} + */ + +/* 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_SRTP_H */ |