xref: /openbsd-src/lib/libssl/man/SSL_get_shared_ciphers.3 (revision 46035553bfdd96e63c94e32da0210227ec2e3cf1)
1.\" $OpenBSD: SSL_get_shared_ciphers.3,v 1.4 2019/06/12 09:36:30 schwarze Exp $
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3.\" Copyright (c) 2016 Ingo Schwarze <schwarze@openbsd.org>
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17.Dd $Mdocdate: June 12 2019 $
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 SEE ALSO
57.Xr ssl 3
58.Sh HISTORY
59.Fn SSL_get_shared_ciphers
60first appeared in SSLeay 0.4.5b and has been available since
61.Ox 2.4 .
62.Sh BUGS
63If the list is too long to fit into
64.Fa len
65bytes, it is silently truncated after the last cipher name that fits,
66and all following ciphers are skipped.
67If the buffer is very short such that even the first cipher name
68does not fit, an empty string is returned even when some shared
69ciphers are actually available.
70.Pp
71There is no easy way to find out how much space is required for
72.Fa buf
73or whether the supplied space was sufficient.
74