manpagez: man pages & more
html files: gio
Home | html | info | man

GDtlsConnection

GDtlsConnection — DTLS connection type

Properties

GDatagramBased * base-socket Read / Write / Construct Only
GTlsCertificate * certificate Read / Write
GTlsDatabase * database Read / Write
GTlsInteraction * interaction Read / Write
GTlsCertificate * peer-certificate Read
GTlsCertificateFlags peer-certificate-errors Read
GTlsRehandshakeMode rehandshake-mode Read / Write / Construct
gboolean require-close-notify Read / Write / Construct

Types and Values

Object Hierarchy

    GInterface
    ╰── GDtlsConnection

Prerequisites

GDtlsConnection requires GDatagramBased and GObject.

Known Derived Interfaces

GDtlsConnection is required by GDtlsClientConnection and GDtlsServerConnection.

Includes

#include <gio/gio.h>

Description

GDtlsConnection is the base DTLS connection class type, which wraps a GDatagramBased and provides DTLS encryption on top of it. Its subclasses, GDtlsClientConnection and GDtlsServerConnection, implement client-side and server-side DTLS, respectively.

For TLS support, see GTlsConnection.

As DTLS is datagram based, GDtlsConnection implements GDatagramBased, presenting a datagram-socket-like API for the encrypted connection. This operates over a base datagram connection, which is also a GDatagramBased (“base-socket”).

To close a DTLS connection, use g_dtls_connection_close().

Neither GDtlsServerConnection or GDtlsClientConnection set the peer address on their base GDatagramBased if it is a GSocket — it is up to the caller to do that if they wish. If they do not, and g_socket_close() is called on the base socket, the GDtlsConnection will not raise a G_IO_ERROR_NOT_CONNECTED error on further I/O.

Functions

g_dtls_connection_set_certificate ()

void
g_dtls_connection_set_certificate (GDtlsConnection *conn,
                                   GTlsCertificate *certificate);

This sets the certificate that conn will present to its peer during the TLS handshake. For a GDtlsServerConnection, it is mandatory to set this, and that will normally be done at construct time.

For a GDtlsClientConnection, this is optional. If a handshake fails with G_TLS_ERROR_CERTIFICATE_REQUIRED, that means that the server requires a certificate, and if you try connecting again, you should call this method first. You can call g_dtls_client_connection_get_accepted_cas() on the failed connection to get a list of Certificate Authorities that the server will accept certificates from.

(It is also possible that a server will allow the connection with or without a certificate; in that case, if you don't provide a certificate, you can tell that the server requested one by the fact that g_dtls_client_connection_get_accepted_cas() will return non-NULL.)

Parameters

conn

a GDtlsConnection

 

certificate

the certificate to use for conn

 

Since: 2.48


g_dtls_connection_get_certificate ()

GTlsCertificate *
g_dtls_connection_get_certificate (GDtlsConnection *conn);

Gets conn 's certificate, as set by g_dtls_connection_set_certificate().

Parameters

conn

a GDtlsConnection

 

Returns

conn 's certificate, or NULL.

[transfer none]

Since: 2.48


g_dtls_connection_get_peer_certificate ()

GTlsCertificate *
g_dtls_connection_get_peer_certificate
                               (GDtlsConnection *conn);

Gets conn 's peer's certificate after the handshake has completed. (It is not set during the emission of “accept-certificate”.)

Parameters

conn

a GDtlsConnection

 

Returns

conn 's peer's certificate, or NULL.

[transfer none]

Since: 2.48


g_dtls_connection_get_peer_certificate_errors ()

GTlsCertificateFlags
g_dtls_connection_get_peer_certificate_errors
                               (GDtlsConnection *conn);

Gets the errors associated with validating conn 's peer's certificate, after the handshake has completed. (It is not set during the emission of “accept-certificate”.)

Parameters

conn

a GDtlsConnection

 

Returns

conn 's peer's certificate errors

Since: 2.48


g_dtls_connection_set_require_close_notify ()

void
g_dtls_connection_set_require_close_notify
                               (GDtlsConnection *conn,
                                gboolean require_close_notify);

Sets whether or not conn expects a proper TLS close notification before the connection is closed. If this is TRUE (the default), then conn will expect to receive a TLS close notification from its peer before the connection is closed, and will return a G_TLS_ERROR_EOF error if the connection is closed without proper notification (since this may indicate a network error, or man-in-the-middle attack).

In some protocols, the application will know whether or not the connection was closed cleanly based on application-level data (because the application-level data includes a length field, or is somehow self-delimiting); in this case, the close notify is redundant and may be omitted. You can use g_dtls_connection_set_require_close_notify() to tell conn to allow an "unannounced" connection close, in which case the close will show up as a 0-length read, as in a non-TLS GDatagramBased, and it is up to the application to check that the data has been fully received.

Note that this only affects the behavior when the peer closes the connection; when the application calls g_dtls_connection_close_async() on conn itself, this will send a close notification regardless of the setting of this property. If you explicitly want to do an unclean close, you can close conn 's “base-socket” rather than closing conn itself.

Parameters

conn

a GDtlsConnection

 

require_close_notify

whether or not to require close notification

 

Since: 2.48


g_dtls_connection_get_require_close_notify ()

gboolean
g_dtls_connection_get_require_close_notify
                               (GDtlsConnection *conn);

Tests whether or not conn expects a proper TLS close notification when the connection is closed. See g_dtls_connection_set_require_close_notify() for details.

Parameters

conn

a GDtlsConnection

 

Returns

TRUE if conn requires a proper TLS close notification.

Since: 2.48


g_dtls_connection_set_rehandshake_mode ()

void
g_dtls_connection_set_rehandshake_mode
                               (GDtlsConnection *conn,
                                GTlsRehandshakeMode mode);

Sets how conn behaves with respect to rehandshaking requests.

G_TLS_REHANDSHAKE_NEVER means that it will never agree to rehandshake after the initial handshake is complete. (For a client, this means it will refuse rehandshake requests from the server, and for a server, this means it will close the connection with an error if the client attempts to rehandshake.)

G_TLS_REHANDSHAKE_SAFELY means that the connection will allow a rehandshake only if the other end of the connection supports the TLS renegotiation_info extension. This is the default behavior, but means that rehandshaking will not work against older implementations that do not support that extension.

G_TLS_REHANDSHAKE_UNSAFELY means that the connection will allow rehandshaking even without the renegotiation_info extension. On the server side in particular, this is not recommended, since it leaves the server open to certain attacks. However, this mode is necessary if you need to allow renegotiation with older client software.

Parameters

conn

a GDtlsConnection

 

mode

the rehandshaking mode

 

Since: 2.48


g_dtls_connection_get_rehandshake_mode ()

GTlsRehandshakeMode
g_dtls_connection_get_rehandshake_mode
                               (GDtlsConnection *conn);

Gets conn rehandshaking mode. See g_dtls_connection_set_rehandshake_mode() for details.

Parameters

conn

a GDtlsConnection

 

Returns

conn 's rehandshaking mode

Since: 2.48


g_dtls_connection_get_database ()

GTlsDatabase *
g_dtls_connection_get_database (GDtlsConnection *conn);

Gets the certificate database that conn uses to verify peer certificates. See g_dtls_connection_set_database().

Parameters

conn

a GDtlsConnection

 

Returns

the certificate database that conn uses or NULL.

[transfer none]

Since: 2.48


g_dtls_connection_set_database ()

void
g_dtls_connection_set_database (GDtlsConnection *conn,
                                GTlsDatabase *database);

Sets the certificate database that is used to verify peer certificates. This is set to the default database by default. See g_dtls_backend_get_default_database(). If set to NULL, then peer certificate validation will always set the G_TLS_CERTIFICATE_UNKNOWN_CA error (meaning “accept-certificate” will always be emitted on client-side connections, unless that bit is not set in “validation-flags”).

Parameters

conn

a GDtlsConnection

 

database

a GTlsDatabase

 

Since: 2.48


g_dtls_connection_get_interaction ()

GTlsInteraction *
g_dtls_connection_get_interaction (GDtlsConnection *conn);

Get the object that will be used to interact with the user. It will be used for things like prompting the user for passwords. If NULL is returned, then no user interaction will occur for this connection.

Parameters

conn

a connection

 

Returns

The interaction object.

[transfer none]

Since: 2.48


g_dtls_connection_set_interaction ()

void
g_dtls_connection_set_interaction (GDtlsConnection *conn,
                                   GTlsInteraction *interaction);

Set the object that will be used to interact with the user. It will be used for things like prompting the user for passwords.

The interaction argument will normally be a derived subclass of GTlsInteraction. NULL can also be provided if no user interaction should occur for this connection.

Parameters

conn

a connection

 

interaction

an interaction object, or NULL.

[nullable]

Since: 2.48


g_dtls_connection_handshake ()

gboolean
g_dtls_connection_handshake (GDtlsConnection *conn,
                             GCancellable *cancellable,
                             GError **error);

Attempts a TLS handshake on conn .

On the client side, it is never necessary to call this method; although the connection needs to perform a handshake after connecting (or after sending a "STARTTLS"-type command) and may need to rehandshake later if the server requests it, GDtlsConnection will handle this for you automatically when you try to send or receive data on the connection. However, you can call g_dtls_connection_handshake() manually if you want to know for sure whether the initial handshake succeeded or failed (as opposed to just immediately trying to write to conn , in which case if it fails, it may not be possible to tell if it failed before or after completing the handshake).

Likewise, on the server side, although a handshake is necessary at the beginning of the communication, you do not need to call this function explicitly unless you want clearer error reporting. However, you may call g_dtls_connection_handshake() later on to renegotiate parameters (encryption methods, etc) with the client.

“accept_certificate” may be emitted during the handshake.

Parameters

conn

a GDtlsConnection

 

cancellable

a GCancellable, or NULL.

[nullable]

error

a GError, or NULL

 

Returns

success or failure

Since: 2.48


g_dtls_connection_handshake_async ()

void
g_dtls_connection_handshake_async (GDtlsConnection *conn,
                                   int io_priority,
                                   GCancellable *cancellable,
                                   GAsyncReadyCallback callback,
                                   gpointer user_data);

Asynchronously performs a TLS handshake on conn . See g_dtls_connection_handshake() for more information.

Parameters

conn

a GDtlsConnection

 

io_priority

the I/O priority of the request

 

cancellable

a GCancellable, or NULL.

[nullable]

callback

callback to call when the handshake is complete

 

user_data

the data to pass to the callback function

 

Since: 2.48


g_dtls_connection_handshake_finish ()

gboolean
g_dtls_connection_handshake_finish (GDtlsConnection *conn,
                                    GAsyncResult *result,
                                    GError **error);

Finish an asynchronous TLS handshake operation. See g_dtls_connection_handshake() for more information.

Parameters

conn

a GDtlsConnection

 

result

a GAsyncResult.

 

error

a GError pointer, or NULL

 

Returns

TRUE on success, FALSE on failure, in which case error will be set.

Since: 2.48


g_dtls_connection_shutdown ()

gboolean
g_dtls_connection_shutdown (GDtlsConnection *conn,
                            gboolean shutdown_read,
                            gboolean shutdown_write,
                            GCancellable *cancellable,
                            GError **error);

Shut down part or all of a DTLS connection.

If shutdown_read is TRUE then the receiving side of the connection is shut down, and further reading is disallowed. Subsequent calls to g_datagram_based_receive_messages() will return G_IO_ERROR_CLOSED.

If shutdown_write is TRUE then the sending side of the connection is shut down, and further writing is disallowed. Subsequent calls to g_datagram_based_send_messages() will return G_IO_ERROR_CLOSED.

It is allowed for both shutdown_read and shutdown_write to be TRUE — this is equivalent to calling g_dtls_connection_close().

If cancellable is cancelled, the GDtlsConnection may be left partially-closed and any pending untransmitted data may be lost. Call g_dtls_connection_shutdown() again to complete closing the GDtlsConnection.

Parameters

conn

a GDtlsConnection

 

shutdown_read

TRUE to stop reception of incoming datagrams

 

shutdown_write

TRUE to stop sending outgoing datagrams

 

cancellable

a GCancellable, or NULL.

[nullable]

error

a GError, or NULL

 

Returns

TRUE on success, FALSE otherwise

Since: 2.48


g_dtls_connection_shutdown_async ()

void
g_dtls_connection_shutdown_async (GDtlsConnection *conn,
                                  gboolean shutdown_read,
                                  gboolean shutdown_write,
                                  int io_priority,
                                  GCancellable *cancellable,
                                  GAsyncReadyCallback callback,
                                  gpointer user_data);

Asynchronously shut down part or all of the DTLS connection. See g_dtls_connection_shutdown() for more information.

Parameters

conn

a GDtlsConnection

 

shutdown_read

TRUE to stop reception of incoming datagrams

 

shutdown_write

TRUE to stop sending outgoing datagrams

 

io_priority

the I/O priority of the request

 

cancellable

a GCancellable, or NULL.

[nullable]

callback

callback to call when the shutdown operation is complete

 

user_data

the data to pass to the callback function

 

Since: 2.48


g_dtls_connection_shutdown_finish ()

gboolean
g_dtls_connection_shutdown_finish (GDtlsConnection *conn,
                                   GAsyncResult *result,
                                   GError **error);

Finish an asynchronous TLS shutdown operation. See g_dtls_connection_shutdown() for more information.

Parameters

conn

a GDtlsConnection

 

result

a GAsyncResult

 

error

a GError pointer, or NULL

 

Returns

TRUE on success, FALSE on failure, in which case error will be set

Since: 2.48


g_dtls_connection_close ()

gboolean
g_dtls_connection_close (GDtlsConnection *conn,
                         GCancellable *cancellable,
                         GError **error);

Close the DTLS connection. This is equivalent to calling g_dtls_connection_shutdown() to shut down both sides of the connection.

Closing a GDtlsConnection waits for all buffered but untransmitted data to be sent before it completes. It then sends a close_notify DTLS alert to the peer and may wait for a close_notify to be received from the peer. It does not close the underlying “base-socket”; that must be closed separately.

Once conn is closed, all other operations will return G_IO_ERROR_CLOSED. Closing a GDtlsConnection multiple times will not return an error.

GDtlsConnections will be automatically closed when the last reference is dropped, but you might want to call this function to make sure resources are released as early as possible.

If cancellable is cancelled, the GDtlsConnection may be left partially-closed and any pending untransmitted data may be lost. Call g_dtls_connection_close() again to complete closing the GDtlsConnection.

Parameters

conn

a GDtlsConnection

 

cancellable

a GCancellable, or NULL.

[nullable]

error

a GError, or NULL

 

Returns

TRUE on success, FALSE otherwise

Since: 2.48


g_dtls_connection_close_async ()

void
g_dtls_connection_close_async (GDtlsConnection *conn,
                               int io_priority,
                               GCancellable *cancellable,
                               GAsyncReadyCallback callback,
                               gpointer user_data);

Asynchronously close the DTLS connection. See g_dtls_connection_close() for more information.

Parameters

conn

a GDtlsConnection

 

io_priority

the I/O priority of the request

 

cancellable

a GCancellable, or NULL.

[nullable]

callback

callback to call when the close operation is complete

 

user_data

the data to pass to the callback function

 

Since: 2.48


g_dtls_connection_close_finish ()

gboolean
g_dtls_connection_close_finish (GDtlsConnection *conn,
                                GAsyncResult *result,
                                GError **error);

Finish an asynchronous TLS close operation. See g_dtls_connection_close() for more information.

Parameters

conn

a GDtlsConnection

 

result

a GAsyncResult

 

error

a GError pointer, or NULL

 

Returns

TRUE on success, FALSE on failure, in which case error will be set

Since: 2.48


g_dtls_connection_emit_accept_certificate ()

gboolean
g_dtls_connection_emit_accept_certificate
                               (GDtlsConnection *conn,
                                GTlsCertificate *peer_cert,
                                GTlsCertificateFlags errors);

Used by GDtlsConnection implementations to emit the “accept-certificate” signal.

Parameters

conn

a GDtlsConnection

 

peer_cert

the peer's GTlsCertificate

 

errors

the problems with peer_cert

 

Returns

TRUE if one of the signal handlers has returned TRUE to accept peer_cert

Since: 2.48

Types and Values

GDtlsConnection

typedef struct _GDtlsConnection GDtlsConnection;

Abstract base class for the backend-specific GDtlsClientConnection and GDtlsServerConnection types.

Since: 2.48

Property Details

The “base-socket” property

  “base-socket”              GDatagramBased *

The GDatagramBased that the connection wraps. Note that this may be any implementation of GDatagramBased, not just a GSocket.

Flags: Read / Write / Construct Only

Since: 2.48


The “certificate” property

  “certificate”              GTlsCertificate *

The connection's certificate; see g_dtls_connection_set_certificate().

Flags: Read / Write

Since: 2.48


The “database” property

  “database”                 GTlsDatabase *

The certificate database to use when verifying this TLS connection. If no certificate database is set, then the default database will be used. See g_dtls_backend_get_default_database().

Flags: Read / Write

Since: 2.48


The “interaction” property

  “interaction”              GTlsInteraction *

A GTlsInteraction object to be used when the connection or certificate database need to interact with the user. This will be used to prompt the user for passwords where necessary.

Flags: Read / Write

Since: 2.48


The “peer-certificate” property

  “peer-certificate”         GTlsCertificate *

The connection's peer's certificate, after the TLS handshake has completed and the certificate has been accepted. Note in particular that this is not yet set during the emission of “accept-certificate”.

(You can watch for a “notify” signal on this property to detect when a handshake has occurred.)

Flags: Read

Since: 2.48


The “peer-certificate-errors” property

  “peer-certificate-errors”  GTlsCertificateFlags

The errors noticed-and-ignored while verifying “peer-certificate”. Normally this should be 0, but it may not be if “validation-flags” is not G_TLS_CERTIFICATE_VALIDATE_ALL, or if “accept-certificate” overrode the default behavior.

Flags: Read

Since: 2.48


The “rehandshake-mode” property

  “rehandshake-mode”         GTlsRehandshakeMode

The rehandshaking mode. See g_dtls_connection_set_rehandshake_mode().

Flags: Read / Write / Construct

Default value: G_TLS_REHANDSHAKE_NEVER

Since: 2.48


The “require-close-notify” property

  “require-close-notify”     gboolean

Whether or not proper TLS close notification is required. See g_dtls_connection_set_require_close_notify().

Flags: Read / Write / Construct

Default value: TRUE

Since: 2.48

Signal Details

The “accept-certificate” signal

gboolean
user_function (GDtlsConnection     *conn,
               GTlsCertificate     *peer_cert,
               GTlsCertificateFlags errors,
               gpointer             user_data)

Emitted during the TLS handshake after the peer certificate has been received. You can examine peer_cert 's certification path by calling g_tls_certificate_get_issuer() on it.

For a client-side connection, peer_cert is the server's certificate, and the signal will only be emitted if the certificate was not acceptable according to conn 's “validation_flags”. If you would like the certificate to be accepted despite errors , return TRUE from the signal handler. Otherwise, if no handler accepts the certificate, the handshake will fail with G_TLS_ERROR_BAD_CERTIFICATE.

For a server-side connection, peer_cert is the certificate presented by the client, if this was requested via the server's “authentication_mode”. On the server side, the signal is always emitted when the client presents a certificate, and the certificate will only be accepted if a handler returns TRUE.

Note that if this signal is emitted as part of asynchronous I/O in the main thread, then you should not attempt to interact with the user before returning from the signal handler. If you want to let the user decide whether or not to accept the certificate, you would have to return FALSE from the signal handler on the first attempt, and then after the connection attempt returns a G_TLS_ERROR_HANDSHAKE, you can interact with the user, and if the user decides to accept the certificate, remember that fact, create a new connection, and return TRUE from the signal handler the next time.

If you are doing I/O in another thread, you do not need to worry about this, and can simply block in the signal handler until the UI thread returns an answer.

Parameters

conn

a GDtlsConnection

 

peer_cert

the peer's GTlsCertificate

 

errors

the problems with peer_cert .

 

user_data

user data set when the signal handler was connected.

 

Returns

TRUE to accept peer_cert (which will also immediately end the signal emission). FALSE to allow the signal emission to continue, which will cause the handshake to fail if no one else overrides it.

Flags: Run Last

Since: 2.48

© manpagez.com 2000-2017
Individual documents may contain additional copyright information.