Section: OpenSSL (3SSL)
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SSL_CTX_set_info_callback, SSL_CTX_get_info_callback, SSL_set_info_callback, SSL_get_info_callback - handle information callback for SSL connections
void SSL_CTX_set_info_callback(SSL_CTX *ctx, void (*callback)());
void (*SSL_CTX_get_info_callback(const SSL_CTX *ctx))();
void SSL_set_info_callback(SSL *ssl, void (*callback)());
void (*SSL_get_info_callback(const SSL *ssl))();
sets the callback
function, that can be used to
obtain state information for SSL
objects created from ctx
setup and use. The setting for ctx
is overridden from the setting for
a specific SSL
object, if specified.
not callback function is used.
SSL_set_info_callback() sets the callback function, that can be used to
obtain state information for ssl during connection setup and use.
When callback is NULL, the callback setting currently valid for
ctx is used.
SSL_CTX_get_info_callback() returns a pointer to the currently set information
callback function for ctx.
SSL_get_info_callback() returns a pointer to the currently set information
callback function for ssl.
When setting up a connection and during use, it is possible to obtain state
information from the SSL/TLS
engine. When set, an information callback function
is called whenever the state changes, an alert appears, or an error occurs.
The callback function is called as callback(SSL *ssl, int where, int ret).
The where argument specifies information about where (in which context)
the callback function was called. If ret is 0, an error condition occurred.
If an alert is handled, SSL_CB_ALERT is set and ret specifies the alert
where is a bitmask made up of the following bits:
Callback has been called to indicate state change inside a loop.
Callback has been called to indicate error exit of a handshake function.
(May be soft error with retry option for non-blocking setups.)
Callback has been called during read operation.
Callback has been called during write operation.
Callback has been called due to an alert being sent or received.
- SSL_CB_READ_ALERT (SSL_CB_ALERT|SSL_CB_READ)
- SSL_CB_WRITE_ALERT (SSL_CB_ALERT|SSL_CB_WRITE)
- SSL_CB_ACCEPT_LOOP (SSL_ST_ACCEPT|SSL_CB_LOOP)
- SSL_CB_ACCEPT_EXIT (SSL_ST_ACCEPT|SSL_CB_EXIT)
- SSL_CB_CONNECT_LOOP (SSL_ST_CONNECT|SSL_CB_LOOP)
- SSL_CB_CONNECT_EXIT (SSL_ST_CONNECT|SSL_CB_EXIT)
Callback has been called because a new handshake is started.
- SSL_CB_HANDSHAKE_DONE 0x20
Callback has been called because a handshake is finished.
The current state information can be obtained using the
SSL_state_string(3) family of functions.
The ret information can be evaluated using the
SSL_alert_type_string(3) family of functions.
does not provide diagnostic information.
SSL_get_info_callback() returns the current setting.
The following example callback function prints state strings, information
about alerts being handled and error messages to the bio_err BIO.
void apps_ssl_info_callback(SSL *s, int where, int ret)
const char *str;
if (w & SSL_ST_CONNECT) str="SSL_connect";
else if (w & SSL_ST_ACCEPT) str="SSL_accept";
if (where & SSL_CB_LOOP)
else if (where & SSL_CB_ALERT)
str=(where & SSL_CB_READ)?"read":"write";
BIO_printf(bio_err,"SSL3 alert %s:%s:%s\n",
else if (where & SSL_CB_EXIT)
if (ret == 0)
BIO_printf(bio_err,"%s:failed in %s\n",
else if (ret < 0)
BIO_printf(bio_err,"%s:error in %s\n",
- RETURN VALUES
- SEE ALSO