b632d80ddd390418dcd5655929bf157a4749ce2e
[exim.git] / src / src / dane.c
1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
4
5 /* Copyright (c) University of Cambridge 1995 - 2012, 2014 */
6 /* See the file NOTICE for conditions of use and distribution. */
7
8 /* This module provides DANE (RFC6659) support for Exim. See also
9 the draft RFC for DANE-over-SMTP, "SMTP security via opportunistic DANE TLS"
10 (V. Dukhovni, W. Hardaker) - version 10, dated May 25, 2014.
11
12 The code for DANE support with Openssl was provided by V.Dukhovni.
13
14 No cryptographic code is included in Exim. All this module does is to call
15 functions from the OpenSSL or GNU TLS libraries. */
16
17
18 #include "exim.h"
19
20 /* This module is compiled only when it is specifically requested in the
21 build-time configuration. However, some compilers don't like compiling empty
22 modules, so keep them happy with a dummy when skipping the rest. Make it
23 reference itself to stop picky compilers complaining that it is unused, and put
24 in a dummy argument to stop even pickier compilers complaining about infinite
25 loops. */
26
27 #ifndef EXPERIMENTAL_DANE
28 static void dummy(int x) { dummy(x-1); }
29 #else
30
31 /* Enabling DANE without enabling TLS cannot work. Abort the compilation. */
32 # ifndef SUPPORT_TLS
33 # error DANE support requires that TLS support must be enabled. Abort build.
34 # endif
35
36 /* DNSSEC support is also required */
37 # ifndef RES_USE_DNSSEC
38 # error DANE support requires that the DNS resolver library supports DNSSEC
39 # endif
40
41 # ifndef USE_GNUTLS
42 # include "dane-openssl.c"
43 # endif
44
45
46 #endif /* EXPERIMENTAL_DANE */
47
48 /* End of dane.c */