=pod

=head1 NAME

SSL_get1_supported_ciphers, SSL_get_client_ciphers,
SSL_get_ciphers, SSL_CTX_get_ciphers,
SSL_bytes_to_cipher_list, SSL_get_cipher_list
- get list of available SSL_CIPHERs

=head1 SYNOPSIS

 #include <openssl/ssl.h>

 STACK_OF(SSL_CIPHER) *SSL_get_ciphers(const SSL *ssl);
 STACK_OF(SSL_CIPHER) *SSL_CTX_get_ciphers(const SSL_CTX *ctx);
 STACK_OF(SSL_CIPHER) *SSL_get1_supported_ciphers(SSL *s);
 STACK_OF(SSL_CIPHER) *SSL_get_client_ciphers(const SSL *ssl);
 STACK_OF(SSL_CIPHER) *SSL_bytes_to_cipher_list(SSL *s,
                                                const unsigned char *bytes,
                                                size_t len, int isv2format)
 const char *SSL_get_cipher_list(const SSL *ssl, int priority);

=head1 DESCRIPTION

SSL_get_ciphers() returns the stack of available SSL_CIPHERs for B<ssl>,
sorted by preference. If B<ssl> is NULL or no ciphers are available, NULL
is returned.

SSL_CTX_get_ciphers() returns the stack of available SSL_CIPHERs for B<ctx>.

SSL_get1_supported_ciphers() returns the stack of enabled SSL_CIPHERs for
B<ssl>, sorted by preference.
The list depends on settings like the cipher list, the supported protocol
versions, the security level, and the enabled signature algorithms.
SRP and PSK ciphers are only enabled if the appropriate callbacks or settings
have been applied.
This is the list that will be sent by the client to the server.
The list supported by the server might include more ciphers in case there is a
hole in the list of supported protocols.
The server will also not use ciphers from this list depending on the
configured certificates and DH parameters.
If B<ssl> is NULL or no ciphers are available, NULL is returned.

SSL_get_client_ciphers() returns the stack of available SSL_CIPHERs matching the
list received from the client on B<ssl>. If B<ssl> is NULL, no ciphers are
available, or B<ssl> is not operating in server mode, NULL is returned.

SSL_bytes_to_cipher_list() treats the supplied B<len> octets in B<bytes>
as a wire-protocol cipher suite specification (in the three-octet-per-cipher
SSLv2 wire format if B<isv2format> is nonzero; otherwise the two-octet
SSLv3/TLS wire format), and parses the cipher suites supported by the library
into the returned stack of SSL_CIPHER objects.  Unsupported cipher suites
are ignored, and NULL is returned on error.

SSL_get_cipher_list() returns a pointer to the name of the SSL_CIPHER
listed for B<ssl> with B<priority>. If B<ssl> is NULL, no ciphers are
available, or there are less ciphers than B<priority> available, NULL
is returned.

=head1 NOTES

The details of the ciphers obtained by SSL_get_ciphers(), SSL_CTX_get_ciphers()
SSL_get1_supported_ciphers() and SSL_get_client_ciphers() can be obtained using
the L<SSL_CIPHER_get_name(3)> family of functions.

Call SSL_get_cipher_list() with B<priority> starting from 0 to obtain the
sorted list of available ciphers, until NULL is returned.

Note: SSL_get_ciphers(), SSL_CTX_get_ciphers() and SSL_get_client_ciphers()
return a pointer to an internal cipher stack, which will be freed later on when
the SSL or SSL_SESSION object is freed.  Therefore, the calling code B<MUST NOT>
free the return value itself.

The stack returned by SSL_get1_supported_ciphers() should be freed using
sk_SSL_CIPHER_free().

The stack returned by SSL_bytes_to_cipher_list() should be freed using
sk_SSL_CIPHER_free().

=head1 RETURN VALUES

See DESCRIPTION

=head1 BUGS

The implementation of SSL_bytes_to_cipher_list() mutates state in the
supplied SSL object B<s>; SSL_bytes_to_cipher_list() should not be called
on a server SSL object after that server has processed the received ClientHello.

=head1 SEE ALSO

L<ssl(7)>, L<SSL_CTX_set_cipher_list(3)>,
L<SSL_CIPHER_get_name(3)>

=head1 COPYRIGHT

Copyright 2000-2016 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>.

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