NAME

       SSL_CTX_use_serverinfo_ex, SSL_CTX_use_serverinfo, SSL_CTX_use_serverinfo_file - use
       serverinfo extension

SYNOPSIS

        #include <openssl/ssl.h>

        int SSL_CTX_use_serverinfo_ex(SSL_CTX *ctx, unsigned int version,
                                      const unsigned char *serverinfo,
                                      size_t serverinfo_length);

        int SSL_CTX_use_serverinfo(SSL_CTX *ctx, const unsigned char *serverinfo,
                                   size_t serverinfo_length);

        int SSL_CTX_use_serverinfo_file(SSL_CTX *ctx, const char *file);

DESCRIPTION

       These functions load "serverinfo" TLS extensions into the SSL_CTX. A "serverinfo"
       extension is returned in response to an empty ClientHello Extension.

       SSL_CTX_use_serverinfo_ex() loads one or more serverinfo extensions from a byte array into
       ctx. The version parameter specifies the format of the byte array provided in *serverinfo
       which is of length serverinfo_length.

       If version is SSL_SERVERINFOV2 then the extensions in the array must consist of a 4-byte
       context, a 2-byte Extension Type, a 2-byte length, and then length bytes of
       extension_data. The context and type values have the same meaning as for
       SSL_CTX_add_custom_ext(3). If serverinfo is being loaded for extensions to be added to a
       Certificate message, then the extension will only be added for the first certificate in
       the message (which is always the end-entity certificate).

       If version is SSL_SERVERINFOV1 then the extensions in the array must consist of a 2-byte
       Extension Type, a 2-byte length, and then length bytes of extension_data. The type value
       has the same meaning as for SSL_CTX_add_custom_ext(3). The following default context value
       will be used in this case:

        SSL_EXT_TLS1_2_AND_BELOW_ONLY | SSL_EXT_CLIENT_HELLO
        | SSL_EXT_TLS1_2_SERVER_HELLO | SSL_EXT_IGNORE_ON_RESUMPTION

       SSL_CTX_use_serverinfo() does the same thing as SSL_CTX_use_serverinfo_ex() except that
       there is no version parameter so a default version of SSL_SERVERINFOV1 is used instead.

       SSL_CTX_use_serverinfo_file() loads one or more serverinfo extensions from file into ctx.
       The extensions must be in PEM format.  Each extension must be in a format as described
       above for SSL_CTX_use_serverinfo_ex().  Each PEM extension name must begin with the phrase
       "BEGIN SERVERINFOV2 FOR " for SSL_SERVERINFOV2 data or "BEGIN SERVERINFO FOR " for
       SSL_SERVERINFOV1 data.

       If more than one certificate (RSA/DSA) is installed using SSL_CTX_use_certificate(), the
       serverinfo extension will be loaded into the last certificate installed.  If e.g. the last
       item was a RSA certificate, the loaded serverinfo extension data will be loaded for that
       certificate.  To use the serverinfo extension for multiple certificates,
       SSL_CTX_use_serverinfo() needs to be called multiple times, once after each time a
       certificate is loaded via a call to SSL_CTX_use_certificate().

RETURN VALUES

       On success, the functions return 1.  On failure, the functions return 0.  Check out the
       error stack to find out the reason.

COPYRIGHT

       Copyright 2013-2017 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 <https://www.openssl.org/source/license.html>.