Index: libsrtp/include/srtp.h |
=================================================================== |
--- libsrtp/include/srtp.h (revision 0) |
+++ libsrtp/include/srtp.h (revision 0) |
@@ -0,0 +1,1006 @@ |
+/* |
+ * 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_shutdown() de-initializes the srtp library. |
+ * |
+ * @warning No srtp functions may be called after calling this function. |
+ */ |
+ |
+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 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 RFC 4568 (SDP Security Descriptions for |
+ * Media Streams). |
+ * |
+ * @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 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 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 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 crypto_policy_set_aes_cm_256_hmac_sha1_80(&p) |
+ * sets the crypto_policy_t at location p to use policy |
+ * AES_CM_256_HMAC_SHA1_80 as defined in |
+ * draft-ietf-avt-srtp-big-aes-03.txt. 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 crypto_policy_t datatype. |
+ * |
+ * @return void. |
+ * |
+ */ |
+ |
+void crypto_policy_set_aes_cm_256_hmac_sha1_80(crypto_policy_t *p); |
+ |
+ |
+/** |
+ * @brief 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 crypto_policy_set_aes_cm_256_hmac_sha1_32(&p) |
+ * sets the crypto_policy_t at location p to use policy |
+ * AES_CM_256_HMAC_SHA1_32 as defined in |
+ * draft-ietf-avt-srtp-big-aes-03.txt. 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 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_256_hmac_sha1_32(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 */ |
Property changes on: libsrtp/include/srtp.h |
___________________________________________________________________ |
Added: svn:eol-style |
+ LF |