Imported OpenSSL 1.1.1a

doc/man3/SSL_CTX_set_tlsext_servername_callback.pod

@@ -0,0 +1,77 @@
+=pod
+
+=head1 NAME
+
+SSL_CTX_set_tlsext_servername_callback, SSL_CTX_set_tlsext_servername_arg,
+SSL_get_servername_type, SSL_get_servername,
+SSL_set_tlsext_host_name - handle server name indication (SNI)
+
+=head1 SYNOPSIS
+
+ #include <openssl/ssl.h>
+
+ long SSL_CTX_set_tlsext_servername_callback(SSL_CTX *ctx,
+                                   int (*cb)(SSL *, int *, void *));
+ long SSL_CTX_set_tlsext_servername_arg(SSL_CTX *ctx, void *arg);
+
+ const char *SSL_get_servername(const SSL *s, const int type);
+ int SSL_get_servername_type(const SSL *s);
+
+ int SSL_set_tlsext_host_name(const SSL *s, const char *name);
+
+=head1 DESCRIPTION
+
+The functionality provided by the servername callback is superseded by the
+ClientHello callback, which can be set using SSL_CTX_set_client_hello_cb().
+The servername callback is retained for historical compatibility.
+
+SSL_CTX_set_tlsext_servername_callback() sets the application callback B<cb>
+used by a server to perform any actions or configuration required based on
+the servername extension received in the incoming connection. When B<cb>
+is NULL, SNI is not used. The B<arg> value is a pointer which is passed to
+the application callback.
+
+SSL_CTX_set_tlsext_servername_arg() sets a context-specific argument to be
+passed into the callback for this B<SSL_CTX>.
+
+SSL_get_servername() returns a servername extension value of the specified
+type if provided in the Client Hello or NULL.
+
+SSL_get_servername_type() returns the servername type or -1 if no servername
+is present. Currently the only supported type (defined in RFC3546) is
+B<TLSEXT_NAMETYPE_host_name>.
+
+SSL_set_tlsext_host_name() sets the server name indication ClientHello extension
+to contain the value B<name>. The type of server name indication extension is set
+to B<TLSEXT_NAMETYPE_host_name> (defined in RFC3546).
+
+=head1 NOTES
+
+Several callbacks are executed during ClientHello processing, including
+the ClientHello, ALPN, and servername callbacks.  The ClientHello callback is
+executed first, then the servername callback, followed by the ALPN callback.
+
+The SSL_set_tlsext_host_name() function should only be called on SSL objects
+that will act as clients; otherwise the configured B<name> will be ignored.
+
+=head1 RETURN VALUES
+
+SSL_CTX_set_tlsext_servername_callback() and
+SSL_CTX_set_tlsext_servername_arg() both always return 1 indicating success.
+SSL_set_tlsext_host_name() returns 1 on success, 0 in case of error.
+
+=head1 SEE ALSO
+
+L<ssl(7)>, L<SSL_CTX_set_alpn_select_cb(3)>,
+L<SSL_get0_alpn_selected(3)>, L<SSL_CTX_set_client_hello_cb(3)>
+
+=head1 COPYRIGHT
+
+Copyright 2017 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