xref: /freebsd/crypto/openssl/doc/man3/SSL_CTX_use_serverinfo.pod (revision dd41de95a84d979615a2ef11df6850622bf6184e)
1=pod
2
3=head1 NAME
4
5SSL_CTX_use_serverinfo_ex,
6SSL_CTX_use_serverinfo,
7SSL_CTX_use_serverinfo_file
8- use serverinfo extension
9
10=head1 SYNOPSIS
11
12 #include <openssl/ssl.h>
13
14 int SSL_CTX_use_serverinfo_ex(SSL_CTX *ctx, unsigned int version,
15                               const unsigned char *serverinfo,
16                               size_t serverinfo_length);
17
18 int SSL_CTX_use_serverinfo(SSL_CTX *ctx, const unsigned char *serverinfo,
19                            size_t serverinfo_length);
20
21 int SSL_CTX_use_serverinfo_file(SSL_CTX *ctx, const char *file);
22
23=head1 DESCRIPTION
24
25These functions load "serverinfo" TLS extensions into the SSL_CTX. A
26"serverinfo" extension is returned in response to an empty ClientHello
27Extension.
28
29SSL_CTX_use_serverinfo_ex() loads one or more serverinfo extensions from
30a byte array into B<ctx>. The B<version> parameter specifies the format of the
31byte array provided in B<*serverinfo> which is of length B<serverinfo_length>.
32
33If B<version> is B<SSL_SERVERINFOV2> then the extensions in the array must
34consist of a 4-byte context, a 2-byte Extension Type, a 2-byte length, and then
35length bytes of extension_data. The context and type values have the same
36meaning as for L<SSL_CTX_add_custom_ext(3)>. If serverinfo is being loaded for
37extensions to be added to a Certificate message, then the extension will only
38be added for the first certificate in the message (which is always the
39end-entity certificate).
40
41If B<version> is B<SSL_SERVERINFOV1> then the extensions in the array must
42consist of a 2-byte Extension Type, a 2-byte length, and then length bytes of
43extension_data. The type value has the same meaning as for
44L<SSL_CTX_add_custom_ext(3)>. The following default context value will be used
45in this case:
46
47 SSL_EXT_TLS1_2_AND_BELOW_ONLY | SSL_EXT_CLIENT_HELLO
48 | SSL_EXT_TLS1_2_SERVER_HELLO | SSL_EXT_IGNORE_ON_RESUMPTION
49
50SSL_CTX_use_serverinfo() does the same thing as SSL_CTX_use_serverinfo_ex()
51except that there is no B<version> parameter so a default version of
52SSL_SERVERINFOV1 is used instead.
53
54SSL_CTX_use_serverinfo_file() loads one or more serverinfo extensions from
55B<file> into B<ctx>.  The extensions must be in PEM format.  Each extension
56must be in a format as described above for SSL_CTX_use_serverinfo_ex().  Each
57PEM extension name must begin with the phrase "BEGIN SERVERINFOV2 FOR " for
58SSL_SERVERINFOV2 data or "BEGIN SERVERINFO FOR " for SSL_SERVERINFOV1 data.
59
60If more than one certificate (RSA/DSA) is installed using
61SSL_CTX_use_certificate(), the serverinfo extension will be loaded into the
62last certificate installed.  If e.g. the last item was a RSA certificate, the
63loaded serverinfo extension data will be loaded for that certificate.  To
64use the serverinfo extension for multiple certificates,
65SSL_CTX_use_serverinfo() needs to be called multiple times, once B<after>
66each time a certificate is loaded via a call to SSL_CTX_use_certificate().
67
68=head1 RETURN VALUES
69
70On success, the functions return 1.
71On failure, the functions return 0.  Check out the error stack to find out
72the reason.
73
74=head1 COPYRIGHT
75
76Copyright 2013-2017 The OpenSSL Project Authors. All Rights Reserved.
77
78Licensed under the OpenSSL license (the "License").  You may not use
79this file except in compliance with the License.  You can obtain a copy
80in the file LICENSE in the source distribution or at
81L<https://www.openssl.org/source/license.html>.
82
83=cut
84