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.\" ========================================================================
.\"
.IX Title "SSL_SESSION_GET0_HOSTNAME 3"
.TH SSL_SESSION_GET0_HOSTNAME 3 "2023-09-11" "1.1.1w" "OpenSSL"
.\" For nroff, turn off justification.  Always turn off hyphenation; it makes
.\" way too many mistakes in technical documents.
.if n .ad l
.nh
.SH "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
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 1
\& #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);
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
\&\fBSSL_SESSION_get0_hostname()\fR retrieves the \s-1SNI\s0 value that was sent by the
client when the session was created if it was accepted by the server and TLSv1.2
or below was negotiated. Otherwise \s-1NULL\s0 is returned. Note that in TLSv1.3 the
\&\s-1SNI\s0 hostname is negotiated with each handshake including resumption handshakes
and is therefore never associated with the session.
.PP
The value returned is a pointer to memory maintained within \fBs\fR and
should not be free'd.
.PP
\&\fBSSL_SESSION_set1_hostname()\fR sets the \s-1SNI\s0 value for the hostname to a copy of
the string provided in hostname.
.PP
\&\fBSSL_SESSION_get0_alpn_selected()\fR retrieves the selected \s-1ALPN\s0 protocol for this
session and its associated length in bytes. The returned value of \fB*alpn\fR is a
pointer to memory maintained within \fBs\fR and should not be free'd.
.PP
\&\fBSSL_SESSION_set1_alpn_selected()\fR sets the \s-1ALPN\s0 protocol for this session to the
value in \fBalpn\fR which should be of length \fBlen\fR bytes. A copy of the input
value is made, and the caller retains ownership of the memory pointed to by
\&\fBalpn\fR.
.SH "RETURN VALUES"
.IX Header "RETURN VALUES"
\&\fBSSL_SESSION_get0_hostname()\fR returns either a string or \s-1NULL\s0 based on if there
is the \s-1SNI\s0 value sent by client.
.PP
\&\fBSSL_SESSION_set1_hostname()\fR returns 1 on success or 0 on error.
.PP
\&\fBSSL_SESSION_set1_alpn_selected()\fR returns 1 on success or 0 on error.
.SH "SEE ALSO"
.IX Header "SEE ALSO"
\&\fBssl\fR\|(7),
\&\fBd2i_SSL_SESSION\fR\|(3),
\&\fBSSL_SESSION_get_time\fR\|(3),
\&\fBSSL_SESSION_free\fR\|(3)
.SH "HISTORY"
.IX Header "HISTORY"
The \fBSSL_SESSION_set1_hostname()\fR, \fBSSL_SESSION_get0_alpn_selected()\fR and
\&\fBSSL_SESSION_set1_alpn_selected()\fR functions were added in OpenSSL 1.1.1.
.SH "COPYRIGHT"
.IX Header "COPYRIGHT"
Copyright 2016\-2020 The OpenSSL Project Authors. All Rights Reserved.
.PP
Licensed under the OpenSSL license (the \*(L"License\*(R").  You may not use
this file except in compliance with the License.  You can obtain a copy
in the file \s-1LICENSE\s0 in the source distribution or at
<https://www.openssl.org/source/license.html>.