--- /dev/null
+=pod
+
+=head1 NAME
+
+SSL_CTX_set_info_callback, SSL_CTX_get_info_callback, SSL_set_info_callback, SSL_get_info_callback - handle information callback for SSL connections
+
+=head1 SYNOPSIS
+
+ #include <openssl/ssl.h>
+
+ void SSL_CTX_set_info_callback(SSL_CTX *ctx, void (*callback)());
+ void (*SSL_CTX_get_info_callback(SSL_CTX *ctx))();
+
+ void SSL_set_info_callback(SSL *ssl, void (*callback)());
+ void (*SSL_get_info_callback(SSL *ssl))();
+
+ int (*callback)();
+
+=head1 DESCRIPTION
+
+SSL_CTX_set_info_callback() sets the B<callback> function, that can be used to
+obtain state information for SSL objects created from B<ctx> during connection
+setup and use. The setting for B<ctx> is overridden from the setting for
+a specific SSL object, if specified.
+When B<callback> is NULL, not callback function is used.
+
+SSL_set_info_callback() sets the B<callback> function, that can be used to
+obtain state information for B<ssl> during connection setup and use.
+When B<callback> is NULL, the callback setting currently valid for
+B<ctx> is used.
+
+SSL_CTX_get_info_callback() returns a pointer to the currently set information
+callback function for B<ctx>.
+
+SSL_get_info_callback() returns a pointer to the currently set information
+callback function for B<ssl>.
+
+=head1 NOTES
+
+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 B<callback(SSL *ssl, int where, int ret)>.
+The B<where> argument specifies information about where (in which context)
+the callback function was called. If B<ret> is 0, an error condition occured.
+If an alert is handled, SSL_CB_ALERT is set and B<ret> specifies the alert
+information.
+
+B<where> is a bitmask made up of the following bits:
+
+=over 4
+
+=item SSL_CB_LOOP
+
+Callback has been called to indicate state change inside a loop.
+
+=item SSL_CB_EXIT
+
+Callback has been called to indicate error exit of a handshake function.
+(May be soft error with retry option for non-blocking setups.)
+
+=item SSL_CB_READ
+
+Callback has been called during read operation.
+
+=item SSL_CB_WRITE
+
+Callback has been called during write operation.
+
+=item SSL_CB_ALERT
+
+Callback has been called due to an alert being sent or received.
+
+=item SSL_CB_READ_ALERT (SSL_CB_ALERT|SSL_CB_READ)
+
+=item SSL_CB_WRITE_ALERT (SSL_CB_ALERT|SSL_CB_WRITE)
+
+=item SSL_CB_ACCEPT_LOOP (SSL_ST_ACCEPT|SSL_CB_LOOP)
+
+=item SSL_CB_ACCEPT_EXIT (SSL_ST_ACCEPT|SSL_CB_EXIT)
+
+=item SSL_CB_CONNECT_LOOP (SSL_ST_CONNECT|SSL_CB_LOOP)
+
+=item SSL_CB_CONNECT_EXIT (SSL_ST_CONNECT|SSL_CB_EXIT)
+
+=item SSL_CB_HANDSHAKE_START
+
+Callback has been called because a new handshake is started.
+
+=item SSL_CB_HANDSHAKE_DONE 0x20
+
+Callback has been called because a handshake is finished.
+
+=back
+
+The current state information can be obtained using the
+L<SSL_state_string(3)|SSL_state_string(3)> family of functions.
+
+The B<ret> information can be evaluated using the
+L<SSL_alert_type_string(3)|SSL_alert_type_string(3)> family of functions.
+
+=head1 RETURN VALUES
+
+SSL_set_info_callback() does not provide diagnostic information.
+
+SSL_get_info_callback() returns the current setting.
+
+=head1 EXAMPLES
+
+The following example callback function prints state strings, information
+about alerts being handled and error messages to the B<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));
+ }
+ }
+ }
+
+=head1 SEE ALSO
+
+L<ssl(3)|ssl(3)>, L<SSL_state_string(3)|SSL_state_string(3)>,
+L<SSL_alert_type_string(3)|SSL_alert_type_string(3)>
+
+=cut
projects / oweals / openssl.git / commitdiff