=pod

=head1 NAME

SSL_SESSION_get0_hostname,
SSL_SESSION_set1_hostname,
SSL_SESSION_get0_alpn_selected,
SSL_SESSION_set1_alpn_selected
- get and set SNI and ALPN data associated with a session

=head1 SYNOPSIS

 #include <openssl/ssl.h>

 const char *SSL_SESSION_get0_hostname(const SSL_SESSION *s);
 int SSL_SESSION_set1_hostname(SSL_SESSION *s, const char *hostname);

 void SSL_SESSION_get0_alpn_selected(const SSL_SESSION *s,
                                     const unsigned char **alpn,
                                     size_t *len);
 int SSL_SESSION_set1_alpn_selected(SSL_SESSION *s, const unsigned char *alpn,
                                    size_t len);

=head1 DESCRIPTION

SSL_SESSION_get0_hostname() retrieves the SNI value that was sent by the
client when the session was created, or NULL if no value was sent.

The value returned is a pointer to memory maintained within B<s> and
should not be free'd.

SSL_SESSION_set1_hostname() sets the SNI value for the hostname to a copy of
the string provided in hostname.

SSL_SESSION_get0_alpn_selected() retrieves the selected ALPN protocol for this
session and its associated length in bytes. The returned value of B<*alpn> is a
pointer to memory maintained within B<s> and should not be free'd.

SSL_SESSION_set1_alpn_selected() sets the ALPN protocol for this session to the
value in B<alpn> which should be of length B<len> bytes. A copy of the input
value is made, and the caller retains ownership of the memory pointed to by
B<alpn>.

=head1 RETURN VALUES

SSL_SESSION_get0_hostname() returns either a string or NULL based on if there
is the SNI value sent by client.

SSL_SESSION_set1_hostname() returns 1 on success or 0 on error.

SSL_SESSION_set1_alpn_selected() returns 1 on success or 0 on error.

=head1 SEE ALSO

L<ssl(7)>,
L<d2i_SSL_SESSION(3)>,
L<SSL_SESSION_get_time(3)>,
L<SSL_SESSION_free(3)>

=head1 HISTORY

The SSL_SESSION_set1_hostname(), SSL_SESSION_get0_alpn_selected() and
SSL_SESSION_set1_alpn_selected() functions were added in OpenSSL 1.1.1.

=head1 COPYRIGHT

Copyright 2016-2018 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
L<https://www.openssl.org/source/license.html>.

=cut
