mirror of
https://github.com/openssl/openssl.git
synced 2024-12-15 06:01:37 +08:00
0f84cbc3e2
Reviewed-by: Tomas Mraz <tmraz@fedoraproject.org> (Merged from https://github.com/openssl/openssl/pull/12595)
107 lines
3.6 KiB
Plaintext
107 lines
3.6 KiB
Plaintext
=pod
|
|
|
|
=head1 NAME
|
|
|
|
SSL_COMP_add_compression_method, SSL_COMP_get_compression_methods,
|
|
SSL_COMP_get0_name, SSL_COMP_get_id, SSL_COMP_free_compression_methods
|
|
- handle SSL/TLS integrated compression methods
|
|
|
|
=head1 SYNOPSIS
|
|
|
|
#include <openssl/ssl.h>
|
|
|
|
int SSL_COMP_add_compression_method(int id, COMP_METHOD *cm);
|
|
STACK_OF(SSL_COMP) *SSL_COMP_get_compression_methods(void);
|
|
const char *SSL_COMP_get0_name(const SSL_COMP *comp);
|
|
int SSL_COMP_get_id(const SSL_COMP *comp);
|
|
|
|
Deprecated since OpenSSL 1.1.0, can be hidden entirely by defining
|
|
B<OPENSSL_API_COMPAT> with a suitable version value, see
|
|
L<openssl_user_macros(7)>:
|
|
|
|
void SSL_COMP_free_compression_methods(void);
|
|
|
|
=head1 DESCRIPTION
|
|
|
|
SSL_COMP_add_compression_method() adds the compression method B<cm> with
|
|
the identifier B<id> to the list of available compression methods. This
|
|
list is globally maintained for all SSL operations within this application.
|
|
It cannot be set for specific SSL_CTX or SSL objects.
|
|
|
|
SSL_COMP_get_compression_methods() returns a stack of all of the available
|
|
compression methods or NULL on error.
|
|
|
|
SSL_COMP_get0_name() returns the name of the compression method B<comp>.
|
|
|
|
SSL_COMP_get_id() returns the id of the compression method B<comp>.
|
|
|
|
SSL_COMP_free_compression_methods() releases any resources acquired to
|
|
maintain the internal table of compression methods.
|
|
|
|
=head1 NOTES
|
|
|
|
The TLS standard (or SSLv3) allows the integration of compression methods
|
|
into the communication. The TLS RFC does however not specify compression
|
|
methods or their corresponding identifiers, so there is currently no compatible
|
|
way to integrate compression with unknown peers. It is therefore currently not
|
|
recommended to integrate compression into applications. Applications for
|
|
non-public use may agree on certain compression methods. Using different
|
|
compression methods with the same identifier will lead to connection failure.
|
|
|
|
An OpenSSL client speaking a protocol that allows compression (SSLv3, TLSv1)
|
|
will unconditionally send the list of all compression methods enabled with
|
|
SSL_COMP_add_compression_method() to the server during the handshake.
|
|
Unlike the mechanisms to set a cipher list, there is no method available to
|
|
restrict the list of compression method on a per connection basis.
|
|
|
|
An OpenSSL server will match the identifiers listed by a client against
|
|
its own compression methods and will unconditionally activate compression
|
|
when a matching identifier is found. There is no way to restrict the list
|
|
of compression methods supported on a per connection basis.
|
|
|
|
If enabled during compilation, the OpenSSL library will have the
|
|
COMP_zlib() compression method available.
|
|
|
|
=head1 RETURN VALUES
|
|
|
|
SSL_COMP_add_compression_method() may return the following values:
|
|
|
|
=over 4
|
|
|
|
=item Z<>0
|
|
|
|
The operation succeeded.
|
|
|
|
=item Z<>1
|
|
|
|
The operation failed. Check the error queue to find out the reason.
|
|
|
|
=back
|
|
|
|
SSL_COMP_get_compression_methods() returns the stack of compressions methods or
|
|
NULL on error.
|
|
|
|
SSL_COMP_get0_name() returns the name of the compression method or NULL on error.
|
|
|
|
SSL_COMP_get_id() returns the name of the compression method or -1 on error.
|
|
|
|
=head1 SEE ALSO
|
|
|
|
L<ssl(7)>
|
|
|
|
=head1 HISTORY
|
|
|
|
The SSL_COMP_free_compression_methods() function was deprecated in OpenSSL 1.1.0.
|
|
The SSL_COMP_get0_name() and SSL_comp_get_id() functions were added in OpenSSL 1.1.0d.
|
|
|
|
=head1 COPYRIGHT
|
|
|
|
Copyright 2001-2020 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
|
|
L<https://www.openssl.org/source/license.html>.
|
|
|
|
=cut
|