mirror of
https://github.com/openssl/openssl.git
synced 2024-12-21 06:09:35 +08:00
a9c0d8beea
"Early callback" is a little ambiguous now that early data exists. Perhaps "ClientHello callback"? Reviewed-by: Rich Salz <rsalz@openssl.org> Reviewed-by: Ben Kaduk <kaduk@mit.edu> (Merged from https://github.com/openssl/openssl/pull/4349)
152 lines
5.9 KiB
Plaintext
152 lines
5.9 KiB
Plaintext
=pod
|
|
|
|
=head1 NAME
|
|
|
|
SSL_get_error - obtain result code for TLS/SSL I/O operation
|
|
|
|
=head1 SYNOPSIS
|
|
|
|
#include <openssl/ssl.h>
|
|
|
|
int SSL_get_error(const SSL *ssl, int ret);
|
|
|
|
=head1 DESCRIPTION
|
|
|
|
SSL_get_error() returns a result code (suitable for the C "switch"
|
|
statement) for a preceding call to SSL_connect(), SSL_accept(), SSL_do_handshake(),
|
|
SSL_read_ex(), SSL_read(), SSL_peek_ex(), SSL_peek(), SSL_write_ex() or
|
|
SSL_write() on B<ssl>. The value returned by that TLS/SSL I/O function must be
|
|
passed to SSL_get_error() in parameter B<ret>.
|
|
|
|
In addition to B<ssl> and B<ret>, SSL_get_error() inspects the
|
|
current thread's OpenSSL error queue. Thus, SSL_get_error() must be
|
|
used in the same thread that performed the TLS/SSL I/O operation, and no
|
|
other OpenSSL function calls should appear in between. The current
|
|
thread's error queue must be empty before the TLS/SSL I/O operation is
|
|
attempted, or SSL_get_error() will not work reliably.
|
|
|
|
=head1 RETURN VALUES
|
|
|
|
The following return values can currently occur:
|
|
|
|
=over 4
|
|
|
|
=item SSL_ERROR_NONE
|
|
|
|
The TLS/SSL I/O operation completed. This result code is returned
|
|
if and only if B<ret E<gt> 0>.
|
|
|
|
=item SSL_ERROR_ZERO_RETURN
|
|
|
|
The TLS/SSL connection has been closed.
|
|
If the protocol version is SSL 3.0 or higher, this result code is returned only
|
|
if a closure alert has occurred in the protocol, i.e. if the connection has been
|
|
closed cleanly.
|
|
Note that in this case B<SSL_ERROR_ZERO_RETURN> does not necessarily
|
|
indicate that the underlying transport has been closed.
|
|
|
|
=item SSL_ERROR_WANT_READ, SSL_ERROR_WANT_WRITE
|
|
|
|
The operation did not complete; the same TLS/SSL I/O function should be
|
|
called again later. If, by then, the underlying B<BIO> has data
|
|
available for reading (if the result code is B<SSL_ERROR_WANT_READ>)
|
|
or allows writing data (B<SSL_ERROR_WANT_WRITE>), then some TLS/SSL
|
|
protocol progress will take place, i.e. at least part of an TLS/SSL
|
|
record will be read or written. Note that the retry may again lead to
|
|
a B<SSL_ERROR_WANT_READ> or B<SSL_ERROR_WANT_WRITE> condition.
|
|
There is no fixed upper limit for the number of iterations that
|
|
may be necessary until progress becomes visible at application
|
|
protocol level.
|
|
|
|
For socket B<BIO>s (e.g. when SSL_set_fd() was used), select() or
|
|
poll() on the underlying socket can be used to find out when the
|
|
TLS/SSL I/O function should be retried.
|
|
|
|
Caveat: Any TLS/SSL I/O function can lead to either of
|
|
B<SSL_ERROR_WANT_READ> and B<SSL_ERROR_WANT_WRITE>. In particular,
|
|
SSL_read_ex(), SSL_read(), SSL_peek_ex(), or SSL_peek() may want to write data
|
|
and SSL_write() or SSL_write_ex() may want to read data. This is mainly because
|
|
TLS/SSL handshakes may occur at any time during the protocol (initiated by
|
|
either the client or the server); SSL_read_ex(), SSL_read(), SSL_peek_ex(),
|
|
SSL_peek(), SSL_write_ex(), and SSL_write() will handle any pending handshakes.
|
|
|
|
=item SSL_ERROR_WANT_CONNECT, SSL_ERROR_WANT_ACCEPT
|
|
|
|
The operation did not complete; the same TLS/SSL I/O function should be
|
|
called again later. The underlying BIO was not connected yet to the peer
|
|
and the call would block in connect()/accept(). The SSL function should be
|
|
called again when the connection is established. These messages can only
|
|
appear with a BIO_s_connect() or BIO_s_accept() BIO, respectively.
|
|
In order to find out, when the connection has been successfully established,
|
|
on many platforms select() or poll() for writing on the socket file descriptor
|
|
can be used.
|
|
|
|
=item SSL_ERROR_WANT_X509_LOOKUP
|
|
|
|
The operation did not complete because an application callback set by
|
|
SSL_CTX_set_client_cert_cb() has asked to be called again.
|
|
The TLS/SSL I/O function should be called again later.
|
|
Details depend on the application.
|
|
|
|
=item SSL_ERROR_WANT_ASYNC
|
|
|
|
The operation did not complete because an asynchronous engine is still
|
|
processing data. This will only occur if the mode has been set to SSL_MODE_ASYNC
|
|
using L<SSL_CTX_set_mode(3)> or L<SSL_set_mode(3)> and an asynchronous capable
|
|
engine is being used. An application can determine whether the engine has
|
|
completed its processing using select() or poll() on the asynchronous wait file
|
|
descriptor. This file descriptor is available by calling
|
|
L<SSL_get_all_async_fds(3)> or L<SSL_get_changed_async_fds(3)>. The TLS/SSL I/O
|
|
function should be called again later. The function B<must> be called from the
|
|
same thread that the original call was made from.
|
|
|
|
=item SSL_ERROR_WANT_ASYNC_JOB
|
|
|
|
The asynchronous job could not be started because there were no async jobs
|
|
available in the pool (see ASYNC_init_thread(3)). This will only occur if the
|
|
mode has been set to SSL_MODE_ASYNC using L<SSL_CTX_set_mode(3)> or
|
|
L<SSL_set_mode(3)> and a maximum limit has been set on the async job pool
|
|
through a call to L<ASYNC_init_thread(3)>. The application should retry the
|
|
operation after a currently executing asynchronous operation for the current
|
|
thread has completed.
|
|
|
|
=item SSL_ERROR_WANT_CLIENT_HELLO_CB
|
|
|
|
The operation did not complete because an application callback set by
|
|
SSL_CTX_set_client_hello_cb() has asked to be called again.
|
|
The TLS/SSL I/O function should be called again later.
|
|
Details depend on the application.
|
|
|
|
=item SSL_ERROR_SYSCALL
|
|
|
|
Some non-recoverable I/O error occurred.
|
|
The OpenSSL error queue may contain more information on the error.
|
|
For socket I/O on Unix systems, consult B<errno> for details.
|
|
|
|
=item SSL_ERROR_SSL
|
|
|
|
A failure in the SSL library occurred, usually a protocol error. The
|
|
OpenSSL error queue contains more information on the error.
|
|
|
|
=back
|
|
|
|
=head1 SEE ALSO
|
|
|
|
L<ssl(7)>
|
|
|
|
=head1 HISTORY
|
|
|
|
SSL_ERROR_WANT_ASYNC was added in OpenSSL 1.1.0.
|
|
SSL_ERROR_WANT_CLIENT_HELLO_CB was added in OpenSSL 1.1.1.
|
|
|
|
=head1 COPYRIGHT
|
|
|
|
Copyright 2000-2017 The OpenSSL Project Authors. All Rights Reserved.
|
|
|
|
Licensed under the OpenSSL license (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
|
|
L<https://www.openssl.org/source/license.html>.
|
|
|
|
=cut
|