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SSL_CTX_set_info_callback(3)
NAME
  SSL_CTX_set_info_callback, SSL_CTX_get_info_callback - Handle information
  callback for SSL connections

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))( );

DESCRIPTION
  The SSL_CTX_set_info_callback() function 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.

  The SSL_set_info_callback() function 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.

  The SSL_CTX_get_info_callback() function returns a pointer to the currently
  set information callback function for ctx.

  The SSL_get_info_callback() function returns a pointer to the currently set
  information callback function for ssl.

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 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.

  The where argument is a bitmask made up of the following bits:

    ·  SSL_CB_LOOP

       Callback has been called to indicate state change inside a loop.

    ·  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.)

    ·  SSL_CB_READ

       Callback has been called during read operation.

    ·  SSL_CB_WRITE

       Callback has been called during write operation.

    ·  SSL_CB_ALERT

       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)

    ·  SSL_CB_HANDSHAKE_START

       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.

RETURN VALUES
  The SSL_set_info_callback() function does not provide diagnostic
  information. The SSL_get_info_callback() function returns the current
  setting.

EXAMPLES
  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=3Dwhere& ~SSL_ST_MASK;
	       if (w & SSL_ST_CONNECT) str=3D"SSL_connect";
	       else if (w & SSL_ST_ACCEPT) str=3D"SSL_accept";
	       else str=3D"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=3D(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 =3D=3D 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));
			       }
		       }
	       }

SEE ALSO
  Functions: ssl(3), SSL_get_info_callback(3), SSL_set_info_callback(3),
  SSL_state_string(3), SSL_alert_type_string(3)

Index for Section 3

Alphabetical listing for S

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