SSL_GET_VALUE_UINT(3ossl) OpenSSL SSL_GET_VALUE_UINT(3ossl)
NAME
SSL_get_value_uint, SSL_set_value_uint, SSL_get_generic_value_uint,
SSL_set_generic_value_uint, SSL_get_feature_request_uint,
SSL_set_feature_request_uint, SSL_get_feature_peer_request_uint,
SSL_get_feature_negotiated_uint, SSL_get_quic_stream_bidi_local_avail,
SSL_get_quic_stream_bidi_remote_avail,
SSL_get_quic_stream_uni_local_avail,
SSL_get_quic_stream_uni_remote_avail, SSL_VALUE_CLASS_GENERIC,
SSL_VALUE_CLASS_FEATURE_REQUEST, SSL_VALUE_CLASS_FEATURE_PEER_REQUEST,
SSL_VALUE_CLASS_FEATURE_NEGOTIATED,
SSL_VALUE_QUIC_STREAM_BIDI_LOCAL_AVAIL,
SSL_VALUE_QUIC_STREAM_BIDI_REMOTE_AVAIL,
SSL_VALUE_QUIC_STREAM_UNI_LOCAL_AVAIL,
SSL_VALUE_QUIC_STREAM_UNI_REMOTE_AVAIL, SSL_VALUE_QUIC_IDLE_TIMEOUT,
SSL_VALUE_EVENT_HANDLING_MODE, SSL_VALUE_EVENT_HANDLING_MODE_INHERIT,
SSL_VALUE_EVENT_HANDLING_MODE_EXPLICIT,
SSL_VALUE_EVENT_HANDLING_MODE_IMPLICIT, SSL_get_event_handling_mode,
SSL_set_event_handling_mode, SSL_VALUE_STREAM_WRITE_BUF_SIZE,
SSL_get_stream_write_buf_size, SSL_VALUE_STREAM_WRITE_BUF_USED,
SSL_get_stream_write_buf_used, SSL_VALUE_STREAM_WRITE_BUF_AVAIL,
SSL_get_stream_write_buf_avail - manage negotiable features and
configuration values for an SSL object
SYNOPSIS
#include <openssl/ssl.h>
int SSL_get_value_uint(SSL *ssl, uint32_t class_, uint32_t id,
uint64_t *value);
int SSL_set_value_uint(SSL *ssl, uint32_t class_, uint32_t id,
uint64_t value);
#define SSL_VALUE_CLASS_GENERIC
#define SSL_VALUE_CLASS_FEATURE_REQUEST
#define SSL_VALUE_CLASS_FEATURE_PEER_REQUEST
#define SSL_VALUE_CLASS_FEATURE_NEGOTIATED
#define SSL_VALUE_QUIC_STREAM_BIDI_LOCAL_AVAIL
#define SSL_VALUE_QUIC_STREAM_BIDI_REMOTE_AVAIL
#define SSL_VALUE_QUIC_STREAM_UNI_LOCAL_AVAIL
#define SSL_VALUE_QUIC_STREAM_UNI_REMOTE_AVAIL
#define SSL_VALUE_QUIC_IDLE_TIMEOUT
#define SSL_VALUE_EVENT_HANDLING_MODE
#define SSL_VALUE_EVENT_HANDLING_MODE_INHERIT
#define SSL_VALUE_EVENT_HANDLING_MODE_EXPLICIT
#define SSL_VALUE_EVENT_HANDLING_MODE_IMPLICIT
#define SSL_VALUE_STREAM_WRITE_BUF_SIZE
#define SSL_VALUE_STREAM_WRITE_BUF_USED
#define SSL_VALUE_STREAM_WRITE_BUF_AVAIL
The following convenience macros can also be used:
int SSL_get_generic_value_uint(SSL *ssl, uint32_t id, uint64_t *value);
int SSL_set_generic_value_uint(SSL *ssl, uint32_t id, uint64_t value);
int SSL_get_feature_request_uint(SSL *ssl, uint32_t id, uint64_t *value);
int SSL_set_feature_request_uint(SSL *ssl, uint32_t id, uint64_t value);
int SSL_get_feature_peer_request_uint(SSL *ssl, uint32_t id, uint64_t *value);
int SSL_get_feature_negotiated_uint(SSL *ssl, uint32_t id, uint64_t *value);
int SSL_get_quic_stream_bidi_local_avail(SSL *ssl, uint64_t *value);
int SSL_get_quic_stream_bidi_remote_avail(SSL *ssl, uint64_t *value);
int SSL_get_quic_stream_uni_local_avail(SSL *ssl, uint64_t *value);
int SSL_get_quic_stream_uni_remote_avail(SSL *ssl, uint64_t *value);
int SSL_get_event_handling_mode(SSL *ssl, uint64_t *value);
int SSL_set_event_handling_mode(SSL *ssl, uint64_t value);
int SSL_get_stream_write_buf_size(SSL *ssl, uint64_t *value);
int SSL_get_stream_write_buf_avail(SSL *ssl, uint64_t *value);
int SSL_get_stream_write_buf_used(SSL *ssl, uint64_t *value);
DESCRIPTION
SSL_get_value_uint(3) and SSL_set_value_uint() provide access to
configurable parameters for a given SSL object. Amongst other things,
they are used to provide control over the feature negotiation process
during establishment of a connection, and access to statistics about
that connection.
SSL_get_value_uint(3) and SSL_set_value_uint() get and set configurable
values within a given value class. The value classes are enumerated by
SSL_VALUE_CLASS and are as follows:
SSL_VALUE_CLASS_GENERIC
Values in this class do not participate in the feature negotiation
process. They may represent connection parameters which do not
participate in explicit negotiation or provide connection
statistics. Values in this class might be read-write or read-only.
You can access values in this class using the convenience macros
SSL_get_generic_value_uint() and SSL_set_generic_value_uint() for
brevity.
SSL_VALUE_CLASS_FEATURE_REQUEST
Values in this class are read-write, and represent what the local
party is requesting during feature negotiation. Such a request will
not necessarily be honoured; see
SSL_VALUE_CLASS_FEATURE_NEGOTIATED.
A value in this class may become read-only in certain
circumstances; for example, after a connection has been
established, for a value which cannot be renegotiated after
connection establishment. Setting a value in this class after
connection establishment represents a request for online
renegotiation of the specified feature.
You can access values in this class using the convenience macros
SSL_get_feature_request_uint() and SSL_set_feature_request_uint()
for brevity.
SSL_VALUE_CLASS_FEATURE_PEER_REQUEST
Values in this value class are read-only, and represent what was
requested by a peer during feature negotiation. Such a request has
not necessarily been honoured; see
SSL_VALUE_CLASS_FEATURE_NEGOTIATED.
You can access values in this class using the convenience macro
SSL_get_feature_peer_request_uint() for brevity.
SSL_VALUE_CLASS_FEATURE_NEGOTIATED
Values in this value class are read-only, and represent the value
which was actually negotiated based on both local and peer input
during feature negotiation. This is the effective value in actual
use.
Attempting to read a value in this class will generally fail if the
feature negotiation process has not yet completed and the value is
therefore currently unknown, unless the nature of the feature in
question causes a provisional value to be used prior to completion
of feature negotiation, in which case that value may be returned.
If an online (post-handshake) renegotiation of a feature is in
progress, retrieving the negotiated value will continue to retrieve
the previous negotiated value until that process is completed. See
the documentation of specific values for full details of its
behaviour.
You can access values in this class using the convenience macro
SSL_get_feature_negotiated_uint() for brevity.
CONFIGURABLE VALUES FOR QUIC OBJECTS
The following configurable values are supported for QUIC SSL objects.
Whether a value is supported for a QUIC connection SSL object or a QUIC
stream SSL object is indicated in the heading for each value. Values
supported for QUIC stream SSL objects are also supported on QUIC
connection SSL objects if they have a default stream attached.
SSL_get_value() does not cause internal event processing to occur
unless the documentation for a specific value specifies otherwise.
SSL_VALUE_QUIC_IDLE_TIMEOUT (connection object)
Negotiated feature value. This configures the desired QUIC idle
timeout in milliseconds, where 0 represents a lack of an idle
timeout. This feature can only be configured prior to connection
establishment and cannot be subsequently changed.
This release of OpenSSL uses a default value of 30 seconds. This
default value may change between releases of OpenSSL.
SSL_VALUE_QUIC_STREAM_BIDI_LOCAL_AVAIL (connection object)
Generic read-only statistical value. The number of bidirectional,
locally-initiated streams available to be created (but not yet
created). For example, a value of 100 would mean that
SSL_new_stream(3) could be called 100 times to create 100
bidirectional streams before SSL_new_stream(3) would block or fail
due to backpressure.
Can be queried using the convenience macro
SSL_get_quic_stream_bidi_local_avail().
SSL_VALUE_QUIC_STREAM_UNI_LOCAL_AVAIL (connection object)
As above, but provides the number of unidirectional, locally-
initiated streams available to be created (but not yet created).
Can be queried using the convenience macro
SSL_get_quic_stream_uni_local_avail().
SSL_VALUE_QUIC_STREAM_BIDI_REMOTE_AVAIL (connection object)
As above, but provides the number of bidirectional, remotely-
initiated streams available to be created (but not yet created) by
the peer. This represents the number of streams the local endpoint
has authorised the peer to create in terms of QUIC stream creation
flow control.
Can be queried using the convenience macro
SSL_get_quic_stream_bidi_remote_avail().
SSL_VALUE_QUIC_STREAM_UNI_REMOTE_AVAIL (connection object)
As above, but provides the number of unidirectional, remotely-
initiated streams available to be created (but not yet created).
Can be queried using the convenience macro
SSL_get_quic_stream_uni_remote_avail().
SSL_VALUE_EVENT_HANDLING_MODE (connection or stream object)
Generic value. This is an integer value which takes one of the
following values, and determines the event handling mode in use:
SSL_VALUE_EVENT_HANDLING_MODE_INHERIT
When set, the event handling mode used is inherited from the
value set on the parent connection (for a stream), or, for a
connection, defaults to the implicit event handling model.
When a new connection is created, or a new stream is created or
accepted, it defaults to this setting.
SSL_VALUE_EVENT_HANDLING_MODE_IMPLICIT (Implicit event handling)
If set to this value, the implicit event handling model is
used. Under this model, QUIC objects will automatically perform
background event processing (equivalent to a call to
SSL_handle_events(3)) when calls to I/O functions such as
SSL_read_ex(3) or SSL_write_ex(3) are made on a QUIC SSL
object. This helps to maintain the health of the QUIC
connection and ensures that incoming datagrams and timeout
events are processed.
SSL_VALUE_EVENT_HANDLING_MODE_EXPLICIT (Explicit event handling)
If set to this value, the explicit event handling model is
used. Under this model, nonblocking calls to I/O functions such
as SSL_read_ex(3) or SSL_write_ex(3) do not result in the
automatic processing of QUIC events. Any new incoming network
traffic is not handled; no new outgoing network traffic is
generated, and pending timeout events are not processed. This
allows an application to obtain greater control over the
circumstances in which QUIC event processing occurs. If this
event handling model is used, it is the application's
responsibility to call SSL_handle_events(3) as and when called
for by the QUIC implementation; see the
SSL_get_rpoll_descriptor(3) man page for more information.
Selecting this model does not affect the operation of blocking
I/O calls, which will continue to use the implicit event
handling model. Therefore, applications using this model will
generally want to disable blocking operation using
SSL_set_blocking_mode(3).
Can be configured using the convenience macros
SSL_get_event_handling_mode() and SSL_set_event_handling_mode().
A call to SSL_set_value_uint() which causes this value to switch
back to the implicit event handling model does not in itself cause
implicit event handling to occur; such handling will occur on the
next I/O API call. Equally, a call to SSL_set_value_uint() which
causes this value to switch to the explicit event handling model
will not cause event handling to occur before making that
transition.
This value controls whether implicit event handling occurs when
making an I/O API call on the SSL object it is set on. However,
event processing is not confined to state which relates to only
that object. For example, if you configure explicit event handling
on QUIC stream SSL object "A" and configure implicit event handling
on QUIC stream SSL object "B", a call to an I/O function on "B" may
result in state changes to "A". In other words, if event handling
does happen as a result of an API call to an object related to a
connection, processing of background events (for example, received
QUIC network traffic) may also affect the state of any other object
related to a connection.
SSL_VALUE_STREAM_WRITE_BUF_SIZE (stream object)
Generic read-only statistical value. The size of the write buffer
allocated to hold data written to a stream with SSL_write_ex(3)
until it is transmitted and subsequently acknowledged by the peer.
This value may change at any time, as buffer sizes are optimised in
response to network conditions to optimise throughput.
Can be queried using the convenience macro
SSL_get_stream_write_buf_size().
SSL_VALUE_STREAM_WRITE_BUF_USED (stream object)
Generic read-only statistical value. The number of bytes currently
consumed in the write buffer which have yet to be acknowledged by
the peer. Successful calls to SSL_write_ex(3) which accept data
cause this number to increase. This number will then decrease as
data is acknowledged by the peer.
Can be queried using the convenience macro
SSL_get_stream_write_buf_used().
SSL_VALUE_STREAM_WRITE_BUF_AVAIL (stream object)
Generic read-only statistical value. The number of bytes available
in the write buffer which have yet to be consumed by calls to
SSL_write_ex(3). Successful calls to SSL_write_ex(3) which accept
data cause this number to decrease. This number will increase as
data is acknowledged by the peer. It may also change if the buffer
is resized automatically to optimise throughput.
Can be queried using the convenience macro
SSL_get_stream_write_buf_avail().
No configurable values are currently defined for non-QUIC SSL objects.
RETURN VALUES
Returns 1 on success or 0 on failure. This function can fail for a
number of reasons:
o An argument is invalid (e.g. NULL pointer or invalid class).
o The given value is not supported by the SSL object on which it was
called.
o The given operation (get or set) is not supported by the specified
configurable value.
o You are trying to modify the given value and the value is not
modifiable at this time.
SEE ALSO
SSL_ctrl(3), SSL_get_accept_stream_queue_len(3),
SSL_get_stream_read_state(3), SSL_get_stream_write_state(3),
SSL_get_stream_read_error_code(3), SSL_get_stream_write_error_code(3),
SSL_set_default_stream_mode(3), SSL_set_incoming_stream_policy(3)
HISTORY
These functions were added in OpenSSL 3.3.
COPYRIGHT
Copyright 2002-2024 The OpenSSL Project Authors. All Rights Reserved.
Licensed under the Apache License 2.0 (the "License"). You may not use
this file except in compliance with the License. You can obtain a copy
in the file LICENSE in the source distribution or at
<https://www.openssl.org/source/license.html>.
3.5.0 2025-04-10 SSL_GET_VALUE_UINT(3ossl)
openssl 3.5.0 - Generated Tue Apr 29 18:40:57 CDT 2025