1.\" $OpenBSD: SSL_get_shared_ciphers.3,v 1.1 2016/12/10 14:56:56 schwarze Exp $ 2.\" 3.\" Copyright (c) 2016 Ingo Schwarze <schwarze@openbsd.org> 4.\" 5.\" Permission to use, copy, modify, and distribute this software for any 6.\" purpose with or without fee is hereby granted, provided that the above 7.\" copyright notice and this permission notice appear in all copies. 8.\" 9.\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 10.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 11.\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 12.\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 13.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 14.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 15.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 16.\" 17.Dd $Mdocdate: December 10 2016 $ 18.Dt SSL_GET_SHARED_CIPHERS 3 19.Os 20.Sh NAME 21.Nm SSL_get_shared_ciphers 22.Nd ciphers supported by both client and server 23.Sh SYNOPSIS 24.In openssl/ssl.h 25.Ft char * 26.Fo SSL_get_shared_ciphers 27.Fa "const SSL *ssl" 28.Fa "char *buf" 29.Fa "int len" 30.Fc 31.Sh DESCRIPTION 32.Fn SSL_get_shared_ciphers 33puts the names of the ciphers that are supported by both the client 34and the server of 35.Fa ssl 36into the buffer 37.Fa buf . 38Names are separated by colons. 39At most 40.Fa len 41bytes are written to 42.Fa buf 43including the terminating NUL character. 44.Sh RETURN VALUES 45If 46.Fa ssl 47contains no session, if the session contains no shared ciphers, 48or if 49.Fa len 50is less than 2, 51.Fn SSL_get_shared_ciphers 52returns 53.Dv NULL . 54Otherwise, it returns 55.Fa buf . 56.Sh HISTORY 57.Fn SSL_get_shared_ciphers 58is available in all versions of OpenSSL. 59.Sh BUGS 60If the list is too long to fit into 61.Fa len 62bytes, it is silently truncated after the last cipher name that fits, 63and all following ciphers are skipped. 64If the buffer is very short such that even the first cipher name 65does not fit, an empty string is returned even when some shared 66ciphers are actually available. 67.Pp 68There is no easy way to find out how much space is required for 69.Fa buf 70or whether the supplied space was sufficient. 71