1=pod 2 3=head1 NAME 4 5SSL_SESSION_get0_hostname, 6SSL_SESSION_set1_hostname, 7SSL_SESSION_get0_alpn_selected, 8SSL_SESSION_set1_alpn_selected 9- get and set SNI and ALPN data associated with a session 10 11=head1 SYNOPSIS 12 13 #include <openssl/ssl.h> 14 15 const char *SSL_SESSION_get0_hostname(const SSL_SESSION *s); 16 int SSL_SESSION_set1_hostname(SSL_SESSION *s, const char *hostname); 17 18 void SSL_SESSION_get0_alpn_selected(const SSL_SESSION *s, 19 const unsigned char **alpn, 20 size_t *len); 21 int SSL_SESSION_set1_alpn_selected(SSL_SESSION *s, const unsigned char *alpn, 22 size_t len); 23 24=head1 DESCRIPTION 25 26SSL_SESSION_get0_hostname() retrieves the Server Name Indication (SNI) value 27that was sent by the client when the session was created if the server 28acknowledged the client's SNI extension by including an empty SNI extension 29in response. Otherwise NULL is returned. 30 31The value returned is a pointer to memory maintained within B<s> and 32should not be free'd. 33 34SSL_SESSION_set1_hostname() sets the SNI value for the hostname to a copy of 35the string provided in hostname. 36 37SSL_SESSION_get0_alpn_selected() retrieves the selected ALPN protocol for this 38session and its associated length in bytes. The returned value of B<*alpn> is a 39pointer to memory maintained within B<s> and should not be free'd. 40 41SSL_SESSION_set1_alpn_selected() sets the ALPN protocol for this session to the 42value in B<alpn> which should be of length B<len> bytes. A copy of the input 43value is made, and the caller retains ownership of the memory pointed to by 44B<alpn>. 45 46=head1 RETURN VALUES 47 48SSL_SESSION_get0_hostname() returns the SNI string if available, or NULL if not. 49 50SSL_SESSION_set1_hostname() returns 1 on success or 0 on error. 51 52SSL_SESSION_set1_alpn_selected() returns 1 on success or 0 on error. 53 54=head1 SEE ALSO 55 56L<ssl(7)>, 57L<d2i_SSL_SESSION(3)>, 58L<SSL_SESSION_get_time(3)>, 59L<SSL_SESSION_free(3)> 60 61=head1 HISTORY 62 63The SSL_SESSION_set1_hostname(), SSL_SESSION_get0_alpn_selected() and 64SSL_SESSION_set1_alpn_selected() functions were added in OpenSSL 1.1.1. 65 66=head1 COPYRIGHT 67 68Copyright 2016-2025 The OpenSSL Project Authors. All Rights Reserved. 69 70Licensed under the Apache License 2.0 (the "License"). You may not use 71this file except in compliance with the License. You can obtain a copy 72in the file LICENSE in the source distribution or at 73L<https://www.openssl.org/source/license.html>. 74 75=cut 76