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SSL_CTX_SET_TLSEXT_USE_SRTP(3ossl) OpenSSL SSL_CTX_SET_TLSEXT_USE_SRTP(3ossl)
NAME
SSL_CTX_set_tlsext_use_srtp, SSL_set_tlsext_use_srtp,
SSL_get_srtp_profiles, SSL_get_selected_srtp_profile - Configure and
query SRTP support
SYNOPSIS
#include <openssl/srtp.h>
int SSL_CTX_set_tlsext_use_srtp(SSL_CTX *ctx, const char *profiles);
int SSL_set_tlsext_use_srtp(SSL *ssl, const char *profiles);
STACK_OF(SRTP_PROTECTION_PROFILE) *SSL_get_srtp_profiles(SSL *ssl);
SRTP_PROTECTION_PROFILE *SSL_get_selected_srtp_profile(SSL *s);
DESCRIPTION
SRTP is the Secure Real-Time Transport Protocol. OpenSSL implements
support for the "use_srtp" DTLS extension defined in RFC5764. This
provides a mechanism for establishing SRTP keying material, algorithms
and parameters using DTLS. This capability may be used as part of an
implementation that conforms to RFC5763. OpenSSL does not implement
SRTP itself or RFC5763. Note that OpenSSL does not support the use of
SRTP Master Key Identifiers (MKIs). Also note that this extension is
only supported in DTLS. Any SRTP configuration will be ignored if a TLS
connection is attempted.
An OpenSSL client wishing to send the "use_srtp" extension should call
SSL_CTX_set_tlsext_use_srtp() to set its use for all SSL objects
subsequently created from an SSL_CTX. Alternatively a client may call
SSL_set_tlsext_use_srtp() to set its use for an individual SSL object.
The profiles parameters should point to a NUL-terminated, colon
delimited list of SRTP protection profile names.
The currently supported protection profile names are:
SRTP_AES128_CM_SHA1_80
This corresponds to SRTP_AES128_CM_HMAC_SHA1_80 defined in RFC5764.
SRTP_AES128_CM_SHA1_32
This corresponds to SRTP_AES128_CM_HMAC_SHA1_32 defined in RFC5764.
SRTP_AEAD_AES_128_GCM
This corresponds to the profile of the same name defined in
RFC7714.
SRTP_AEAD_AES_256_GCM
This corresponds to the profile of the same name defined in
RFC7714.
Supplying an unrecognised protection profile name will result in an
error.
An OpenSSL server wishing to support the "use_srtp" extension should
also call SSL_CTX_set_tlsext_use_srtp() or SSL_set_tlsext_use_srtp() to
indicate the protection profiles that it is willing to negotiate.
The currently configured list of protection profiles for either a
calling SSL_get_selected_srtp_profile(). This function will return NULL
if no SRTP protection profile was negotiated. The memory returned from
this function should not be freed by the caller.
If an SRTP protection profile has been successfully negotiated then the
SRTP keying material (on both the client and server) should be obtained
via a call to SSL_export_keying_material(3). This call should provide a
label value of "EXTRACTOR-dtls_srtp" and a NULL context value
(use_context is 0). The total length of keying material obtained should
be equal to two times the sum of the master key length and the salt
length as defined for the protection profile in use. This provides the
client write master key, the server write master key, the client write
master salt and the server write master salt in that order.
RETURN VALUES
SSL_CTX_set_tlsext_use_srtp() and SSL_set_tlsext_use_srtp() return 0 on
success or 1 on error.
SSL_get_srtp_profiles() returns a stack of SRTP_PROTECTION_PROFILE
objects on success or NULL on error or if no protection profiles have
been configured.
SSL_get_selected_srtp_profile() returns a pointer to an
SRTP_PROTECTION_PROFILE object if one has been negotiated or NULL
otherwise.
SEE ALSO
ssl(7), SSL_export_keying_material(3)
COPYRIGHT
Copyright 2017-2018 The OpenSSL Project Authors. All Rights Reserved.
Licensed under the Apache License 2.0 (the "License"). You may not use
this file except in compliance with the License. You can obtain a copy
in the file LICENSE in the source distribution or at
<https://www.openssl.org/source/license.html>.
3.0.11 2023-09-19
SSL_CTX_SET_TLSEXT_USE_SRTP(3ossl)