NAME
SSL_CTX_use_psk_identity_hint,
SSL_use_psk_identity_hint,
SSL_CTX_set_psk_server_callback,
SSL_set_psk_server_callback —
set PSK identity hint to use
SYNOPSIS
#include
<openssl/ssl.h>
int
SSL_CTX_use_psk_identity_hint(SSL_CTX
*ctx, const char
*hint);
int
SSL_use_psk_identity_hint(SSL
*ssl, const char
*hint);
void
SSL_CTX_set_psk_server_callback(SSL_CTX
*ctx, unsigned int (*callback)(SSL *ssl, const char
*identity, unsigned char *psk, int max_psk_len));
void
SSL_set_psk_server_callback(SSL
*ssl, unsigned int (*callback)(SSL *ssl, const char
*identity, unsigned char *psk, int max_psk_len));
DESCRIPTION
SSL_CTX_use_psk_identity_hint()
sets the given NULL-terminated PSK identity hint
hint to SSL context object ctx.
SSL_use_psk_identity_hint()
sets the given NULL-terminated PSK identity hint
hint to SSL connection object
ssl. If hint is
NULL the current hint from ctx
or ssl is deleted.
In the case where PSK identity hint is
NULL, the server does not send the
ServerKeyExchange
message to the client.
A server application must provide a
callback function which is called when the server receives the
ClientKeyExchange
message from the client. The purpose of the callback function is to validate
the received PSK identity and to fetch the pre-shared key used during the
connection setup phase. The callback is set using functions
SSL_CTX_set_psk_server_callback()
or
SSL_set_psk_server_callback().
The callback function is given the connection in parameter
ssl, NULL-terminated PSK
identity sent by the client in parameter identity, and
a buffer psk of length
max_psk_len bytes where the pre-shared key is to be
stored.
RETURN VALUES
SSL_CTX_use_psk_identity_hint() and
SSL_use_psk_identity_hint() return 1 on success, 0
otherwise.
Return values from the server callback are interpreted as follows:
- >0
- PSK identity was found and the server callback has provided the PSK
successfully in parameter psk. Return value is the
length of psk in bytes. It is an error to return a
value greater than max_psk_len.
If the PSK identity was not found but the callback instructs the protocol to continue anyway, the callback must provide some random data to psk and return the length of the random data, so the connection will fail with “decryption_error” before it will be finished completely.
- 0
- PSK identity was not found. An “unknown_psk_identity” alert message will be sent and the connection setup fails.