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)
SYNOPSIS
#include
<openssl/ssl.h>
long
SSL_CTX_set_tlsext_servername_callback(SSL_CTX
*ctx, int (*cb)(SSL_CTX *, 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);
DESCRIPTION
SSL_CTX_set_tlsext_servername_callback()
sets the application callback cb used by a server to
perform any actions or configuration required based on the servername
extension received in the incoming connection. When cb
is NULL, SNI is not used. The
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
ctx.
SSL_set_tlsext_host_name()
sets the server name indication ClientHello extension to contain the value
name, or clears it if name is
NULL. The type of server name indication extension
is set to TLSEXT_NAMETYPE_host_name as defined in
RFC 3546.
All three functions are implemented as macros.
The ALPN and SNI callbacks are both executed during Client Hello processing. The servername callback is executed first, followed by the ALPN callback.
RETURN VALUES
SSL_CTX_set_tlsext_servername_callback()
and SSL_CTX_set_tlsext_servername_arg() always
return 1 indicating success.
SSL_get_servername() returns a servername
extension value of the specified type if provided in the Client Hello, or
NULL otherwise.
SSL_get_servername_type() returns the
servername type or -1 if no servername is present. Currently the only
supported type (defined in RFC 3546) is
TLSEXT_NAMETYPE_host_name.
SSL_set_tlsext_host_name() returns 1 on
success or 0 in case of an error.
SEE ALSO
HISTORY
These functions first appeared in OpenSSL 0.9.8f and have been available since OpenBSD 4.5.