libcommon: soak up three static functions.
Add new kitchen sink openbsc/utils.h and libcommon/utils.c to make three so far
static functions public (so I can use them in the upcoming OAP code).
A place to put them could have been the gprs_utils.h, but all general functions
in there have a gprs_ prefix, and todo markings to move them away. All other
libcommon headers are too specific, so I opened up this kitchen sink header.
Replace the implementation of encode_big_endian() with a call to
osmo_store64be_ext(). See comments.
Apply the change in Makefiles and C files.
diff --git a/openbsc/src/libcommon/utils.c b/openbsc/src/libcommon/utils.c
new file mode 100644
index 0000000..c47dcae
--- /dev/null
+++ b/openbsc/src/libcommon/utils.c
@@ -0,0 +1,58 @@
+/* OpenBSC kitchen sink */
+
+/* (C) 2015 by sysmocom s.m.f.c GmbH <info@sysmocom.de>
+ * All Rights Reserved
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation; either version 3 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 Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include <openbsc/utils.h>
+#include <osmocom/core/utils.h>
+#include <osmocom/core/bit64gen.h>
+
+/* Wishful thinking to generate a constant time compare */
+int constant_time_cmp(const uint8_t *exp, const uint8_t *rel, const int count)
+{
+ int x = 0, i;
+
+ for (i = 0; i < count; ++i)
+ x |= exp[i] ^ rel[i];
+
+ /* if x is zero, all data was identical */
+ return x? 1 : 0;
+}
+
+
+uint64_t decode_big_endian(const uint8_t *data, size_t data_len)
+{
+ uint64_t value = 0;
+
+ while (data_len > 0) {
+ value = (value << 8) + *data;
+ data += 1;
+ data_len -= 1;
+ }
+
+ return value;
+}
+
+uint8_t *encode_big_endian(uint64_t value, size_t data_len)
+{
+ static uint8_t buf[sizeof(uint64_t)];
+ OSMO_ASSERT(data_len <= ARRAY_SIZE(buf));
+ osmo_store64be_ext(value, buf, data_len);
+ return buf;
+}
+