1=pod 2 3=head1 NAME 4 5SSL_CTX_set1_groups, SSL_CTX_set1_groups_list, SSL_set1_groups, 6SSL_set1_groups_list, SSL_get1_groups, SSL_get_shared_group, 7SSL_CTX_set1_curves, SSL_CTX_set1_curves_list, SSL_set1_curves, 8SSL_set1_curves_list, SSL_get1_curves, SSL_get_shared_curve 9- EC supported curve functions 10 11=head1 SYNOPSIS 12 13 #include <openssl/ssl.h> 14 15 int SSL_CTX_set1_groups(SSL_CTX *ctx, int *glist, int glistlen); 16 int SSL_CTX_set1_groups_list(SSL_CTX *ctx, char *list); 17 18 int SSL_set1_groups(SSL *ssl, int *glist, int glistlen); 19 int SSL_set1_groups_list(SSL *ssl, char *list); 20 21 int SSL_get1_groups(SSL *ssl, int *groups); 22 int SSL_get_shared_group(SSL *s, int n); 23 24 int SSL_CTX_set1_curves(SSL_CTX *ctx, int *clist, int clistlen); 25 int SSL_CTX_set1_curves_list(SSL_CTX *ctx, char *list); 26 27 int SSL_set1_curves(SSL *ssl, int *clist, int clistlen); 28 int SSL_set1_curves_list(SSL *ssl, char *list); 29 30 int SSL_get1_curves(SSL *ssl, int *curves); 31 int SSL_get_shared_curve(SSL *s, int n); 32 33=head1 DESCRIPTION 34 35SSL_CTX_set1_groups() sets the supported groups for B<ctx> to B<glistlen> 36groups in the array B<glist>. The array consist of all NIDs of groups in 37preference order. For a TLS client the groups are used directly in the 38supported groups extension. For a TLS server the groups are used to 39determine the set of shared groups. 40 41SSL_CTX_set1_groups_list() sets the supported groups for B<ctx> to 42string B<list>. The string is a colon separated list of group NIDs or 43names, for example "P-521:P-384:P-256". 44 45SSL_set1_groups() and SSL_set1_groups_list() are similar except they set 46supported groups for the SSL structure B<ssl>. 47 48SSL_get1_groups() returns the set of supported groups sent by a client 49in the supported groups extension. It returns the total number of 50supported groups. The B<groups> parameter can be B<NULL> to simply 51return the number of groups for memory allocation purposes. The 52B<groups> array is in the form of a set of group NIDs in preference 53order. It can return zero if the client did not send a supported groups 54extension. 55 56SSL_get_shared_group() returns shared group B<n> for a server-side 57SSL B<ssl>. If B<n> is -1 then the total number of shared groups is 58returned, which may be zero. Other than for diagnostic purposes, 59most applications will only be interested in the first shared group 60so B<n> is normally set to zero. If the value B<n> is out of range, 61NID_undef is returned. 62 63All these functions are implemented as macros. 64 65The curve functions are synonyms for the equivalently named group functions and 66are identical in every respect. They exist because, prior to TLS1.3, there was 67only the concept of supported curves. In TLS1.3 this was renamed to supported 68groups, and extended to include Diffie Hellman groups. The group functions 69should be used in preference. 70 71=head1 NOTES 72 73If an application wishes to make use of several of these functions for 74configuration purposes either on a command line or in a file it should 75consider using the SSL_CONF interface instead of manually parsing options. 76 77=head1 RETURN VALUES 78 79SSL_CTX_set1_groups(), SSL_CTX_set1_groups_list(), SSL_set1_groups() and 80SSL_set1_groups_list(), return 1 for success and 0 for failure. 81 82SSL_get1_groups() returns the number of groups, which may be zero. 83 84SSL_get_shared_group() returns the NID of shared group B<n> or NID_undef if there 85is no shared group B<n>; or the total number of shared groups if B<n> 86is -1. 87 88When called on a client B<ssl>, SSL_get_shared_group() has no meaning and 89returns -1. 90 91=head1 SEE ALSO 92 93L<SSL_CTX_add_extra_chain_cert(3)> 94 95=head1 HISTORY 96 97The curve functions were first added to OpenSSL 1.0.2. The equivalent group 98functions were first added to OpenSSL 1.1.1. 99 100=head1 COPYRIGHT 101 102Copyright 2013-2016 The OpenSSL Project Authors. All Rights Reserved. 103 104Licensed under the OpenSSL license (the "License"). You may not use 105this file except in compliance with the License. You can obtain a copy 106in the file LICENSE in the source distribution or at 107L<https://www.openssl.org/source/license.html>. 108 109=cut 110