SSL_CTX_SET_INFO_CALLBACK(3) | Library Functions Manual | SSL_CTX_SET_INFO_CALLBACK(3) |
SSL_CTX_set_info_callback
,
SSL_CTX_get_info_callback
,
SSL_set_info_callback
,
SSL_get_info_callback
—
handle information callback for SSL connections
#include
<openssl/ssl.h>
void
SSL_CTX_set_info_callback
(SSL_CTX
*ctx, void (*callback)(const SSL *ssl, int where, int
ret));
void
(*SSL_CTX_get_info_callback(const SSL_CTX
*ctx))
(const SSL *ssl, int
where, int ret);
void
SSL_set_info_callback
(SSL *ssl,
void (*callback)(const SSL *ssl, int where, int
ret));
void
(*SSL_get_info_callback(const SSL
*ssl))
(const SSL *ssl, int
where, int ret);
SSL_CTX_set_info_callback
()
sets the callback function that can be used to obtain
state information for SSL objects created from ctx
during connection setup and use. The setting for ctx
is overridden from the setting for a specific SSL object, if specified. When
callback is NULL
, no 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 information.
where is a bitmask made up of the following bits:
SSL_CB_LOOP
SSL_CB_EXIT
SSL_CB_READ
SSL_CB_WRITE
SSL_CB_ALERT
SSL_CB_READ_ALERT
SSL_CB_WRITE_ALERT
SSL_CB_ACCEPT_LOOP
SSL_CB_ACCEPT_EXIT
SSL_CB_CONNECT_LOOP
SSL_CB_CONNECT_EXIT
SSL_CB_HANDSHAKE_START
SSL_CB_HANDSHAKE_DONE
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.
SSL_CTX_get_info_callback
() and
SSL_get_info_callback
() return a pointer to the
current callback or NULL
if none is set.
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; int w; w = where & ~SSL_ST_MASK; if (w & SSL_ST_CONNECT) str = "SSL_connect"; else if (w & SSL_ST_ACCEPT) str = "SSL_accept"; else str = "undefined"; if (where & SSL_CB_LOOP) { BIO_printf(bio_err, "%s:%s\n", str, SSL_state_string_long(s)); } else if (where & SSL_CB_ALERT) { str = (where & SSL_CB_READ) ? "read" : "write"; BIO_printf(bio_err, "SSL3 alert %s:%s:%s\n", str, SSL_alert_type_string_long(ret), SSL_alert_desc_string_long(ret)); } else if (where & SSL_CB_EXIT) { if (ret == 0) BIO_printf(bio_err, "%s:failed in %s\n", str, SSL_state_string_long(s)); else if (ret < 0) { BIO_printf(bio_err, "%s:error in %s\n", str, SSL_state_string_long(s)); } } }
November 30, 2016 | OpenBSD-6.1 |