1# af_alg.m4 serial 4
2dnl Copyright 2018-2021 Free Software Foundation, Inc.
3dnl This file is free software; the Free Software Foundation
4dnl gives unlimited permission to copy and/or distribute it,
5dnl with or without modifications, as long as this notice is preserved.
6
7dnl From Matteo Croce.
8
9AC_DEFUN_ONCE([gl_AF_ALG],
10[
11  AC_REQUIRE([gl_HEADER_SYS_SOCKET])
12  AC_REQUIRE([AC_C_INLINE])
13
14  dnl Check whether linux/if_alg.h has needed features.
15  AC_CACHE_CHECK([whether linux/if_alg.h has struct sockaddr_alg.],
16    [gl_cv_header_linux_if_alg_salg],
17    [AC_COMPILE_IFELSE(
18       [AC_LANG_PROGRAM([[#include <sys/socket.h>
19                          #include <linux/if_alg.h>
20                          struct sockaddr_alg salg = {
21                            .salg_family = AF_ALG,
22                            .salg_type = "hash",
23                            .salg_name = "sha1",
24                          };]])],
25       [gl_cv_header_linux_if_alg_salg=yes],
26       [gl_cv_header_linux_if_alg_salg=no])])
27  if test "$gl_cv_header_linux_if_alg_salg" = yes; then
28    AC_DEFINE([HAVE_LINUX_IF_ALG_H], [1],
29      [Define to 1 if you have 'struct sockaddr_alg' defined.])
30  fi
31
32  dnl The default is to not use AF_ALG if available,
33  dnl as it's system dependent as to whether the kernel
34  dnl routines are faster than libcrypto for example.
35  use_af_alg=no
36  AC_ARG_WITH([linux-crypto],
37    [AS_HELP_STRING([[--with-linux-crypto]],
38       [use Linux kernel cryptographic API (if available)])],
39    [use_af_alg=$withval],
40    [use_af_alg=no])
41  dnl We cannot use it if it is not available.
42  if test "$gl_cv_header_linux_if_alg_salg" != yes; then
43    if test "$use_af_alg" != no; then
44      AC_MSG_WARN([Linux kernel cryptographic API not found])
45    fi
46    use_af_alg=no
47  fi
48
49  if test "$use_af_alg" != no; then
50    USE_AF_ALG=1
51  else
52    USE_AF_ALG=0
53  fi
54  AC_DEFINE_UNQUOTED([USE_LINUX_CRYPTO_API], [$USE_AF_ALG],
55    [Define to 1 if you want to use the Linux kernel cryptographic API.])
56])
57