Add missing crypto.c.

diff --git a/src/crypto.c b/src/crypto.c
new file mode 100644 (file)
index 0000000..cf000c8
--- /dev/null
+++ b/src/crypto.c
@@ -0,0 +1,46 @@
+/*
+    crypto.c -- Cryptographic miscellaneous functions and initialisation
+    Copyright (C) 2014 Guus Sliepen <guus@meshlink.io>
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License along
+    with this program; if not, write to the Free Software Foundation, Inc.,
+    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+*/
+
+#include "system.h"
+
+#include "crypto.h"
+
+//TODO: use a strict random source once to seed a PRNG?
+
+static int random_fd = -1;
+
+void crypto_init(void) {
+       random_fd = open("/dev/urandom", O_RDONLY);
+       if(random_fd < 0)
+               random_fd = open("/dev/random", O_RDONLY);
+       if(random_fd < 0) {
+               fprintf(stderr, "Could not open source of random numbers: %s\n", strerror(errno));
+               abort();
+       }
+}
+
+void crypto_exit(void) {
+}
+
+void randomize(void *out, size_t outlen) {
+       if(read(random_fd, out, outlen) != outlen) {
+               fprintf(stderr, "Error reading random numbers: %s\n", strerror(errno));
+               abort();
+       }
+}