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SSL_CTX_set_tlsext_status_cb(3)     OpenSSL    SSL_CTX_set_tlsext_status_cb(3)

       SSL_CTX_set_tlsext_status_cb, SSL_CTX_get_tlsext_status_cb,
       SSL_CTX_set_tlsext_status_arg, SSL_CTX_get_tlsext_status_arg,
       SSL_CTX_set_tlsext_status_type, SSL_CTX_get_tlsext_status_type,
       SSL_set_tlsext_status_type, SSL_get_tlsext_status_type,
       SSL_get_tlsext_status_ocsp_resp, SSL_set_tlsext_status_ocsp_resp - OCSP
       Certificate Status Request functions

       libcrypto, -lcrypto

        #include <openssl/tls1.h>

        long SSL_CTX_set_tlsext_status_cb(SSL_CTX *ctx, int (*callback)(SSL *, void *));
        long SSL_CTX_get_tlsext_status_cb(SSL_CTX *ctx, int (**callback)(SSL *, void *));

        long SSL_CTX_set_tlsext_status_arg(SSL_CTX *ctx, void *arg);
        long SSL_CTX_get_tlsext_status_arg(SSL_CTX *ctx, void **arg);

        long SSL_CTX_set_tlsext_status_type(SSL_CTX *ctx, int type);
        long SSL_CTX_get_tlsext_status_type(SSL_CTX *ctx);

        long SSL_set_tlsext_status_type(SSL *s, int type);
        long SSL_get_tlsext_status_type(SSL *s);

        long SSL_get_tlsext_status_ocsp_resp(ssl, unsigned char **resp);
        long SSL_set_tlsext_status_ocsp_resp(ssl, unsigned char *resp, int len);

       A client application may request that a server send back an OCSP status
       response (also known as OCSP stapling). To do so the client should call
       the SSL_CTX_set_tlsext_status_type() function prior to the creation of
       any SSL objects. Alternatively an application can call the
       SSL_set_tlsext_status_type() function on an individual SSL object prior
       to the start of the handshake.  Currently the only supported type is
       TLSEXT_STATUSTYPE_ocsp. This value should be passed in the type
       argument. Calling SSL_CTX_get_tlsext_status_type() will return the type
       TLSEXT_STATUSTYPE_ocsp previously set via
       SSL_CTX_set_tlsext_status_type() or -1 if not set.

       The client should additionally provide a callback function to decide
       what to do with the returned OCSP response by calling
       SSL_CTX_set_tlsext_status_cb(). The callback function should determine
       whether the returned OCSP response is acceptable or not. The callback
       will be passed as an argument the value previously set via a call to
       SSL_CTX_set_tlsext_status_arg(). Note that the callback will not be
       called in the event of a handshake where session resumption occurs
       (because there are no Certificates exchanged in such a handshake).  The
       callback previously set via SSL_CTX_set_tlsext_status_cb() can be
       retrieved by calling SSL_CTX_get_tlsext_status_cb(), and the argument
       by calling SSL_CTX_get_tlsext_status_arg().

       On the client side SSL_get_tlsext_status_type() can be used to
       determine whether the client has previously called
       SSL_set_tlsext_status_type(). It will return TLSEXT_STATUSTYPE_ocsp if
       it has been called or -1 otherwise. On the server side
       SSL_get_tlsext_status_type() can be used to determine whether the
       client requested OCSP stapling. If the client requested it then this
       function will return TLSEXT_STATUSTYPE_ocsp, or -1 otherwise.

       The response returned by the server can be obtained via a call to
       SSL_get_tlsext_status_ocsp_resp(). The value *resp will be updated to
       point to the OCSP response data and the return value will be the length
       of that data.  Typically a callback would obtain an OCSP_RESPONSE
       object from this data via a call to the d2i_OCSP_RESPONSE() function.
       If the server has not provided any response data then *resp will be
       NULL and the return value from SSL_get_tlsext_status_ocsp_resp() will
       be -1.

       A server application must also call the SSL_CTX_set_tlsext_status_cb()
       function if it wants to be able to provide clients with OCSP
       Certificate Status responses. Typically the server callback would
       obtain the server certificate that is being sent back to the client via
       a call to SSL_get_certificate(); obtain the OCSP response to be sent
       back; and then set that response data by calling
       SSL_set_tlsext_status_ocsp_resp(). A pointer to the response data
       should be provided in the resp argument, and the length of that data
       should be in the len argument.

       The callback when used on the client side should return a negative
       value on error; 0 if the response is not acceptable (in which case the
       handshake will fail) or a positive value if it is acceptable.

       The callback when used on the server side should return with either
       SSL_TLSEXT_ERR_OK (meaning that the OCSP response that has been set
       should be returned), SSL_TLSEXT_ERR_NOACK (meaning that an OCSP
       response should not be returned) or SSL_TLSEXT_ERR_ALERT_FATAL (meaning
       that a fatal error has occurred).

       SSL_CTX_set_tlsext_status_cb(), SSL_CTX_set_tlsext_status_arg(),
       SSL_CTX_set_tlsext_status_type(), SSL_set_tlsext_status_type() and
       SSL_set_tlsext_status_ocsp_resp() return 0 on error or 1 on success.

       SSL_CTX_get_tlsext_status_type() returns the value previously set by
       SSL_CTX_set_tlsext_status_type(), or -1 if not set.

       SSL_get_tlsext_status_ocsp_resp() returns the length of the OCSP
       response data or -1 if there is no OCSP response data.

       SSL_get_tlsext_status_type() returns TLSEXT_STATUSTYPE_ocsp on the
       client side if SSL_set_tlsext_status_type() was previously called, or
       on the server side if the client requested OCSP stapling. Otherwise -1
       is returned.

       The SSL_get_tlsext_status_type(), SSL_CTX_get_tlsext_status_type() and
       SSL_CTX_set_tlsext_status_type() functions were added in OpenSSL 1.1.0.

       Copyright 2015-2016 The OpenSSL Project Authors. All Rights Reserved.

       Licensed under the OpenSSL license (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

1.1.1i                            2019-03-12   SSL_CTX_set_tlsext_status_cb(3)