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SSL_SESSION_get0_hostname(3)        OpenSSL       SSL_SESSION_get0_hostname(3)

       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 ssociated with a session

       libcrypto, -lcrypto

        #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);

       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 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 *alpn is a pointer to memory maintained within s and should not be

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

       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.

       ssl(7), d2i_SSL_SESSION(3), SSL_SESSION_get_time(3),

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

       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

1.1.1                             2018-09-17      SSL_SESSION_get0_hostname(3)