buffet: Move privetd sources into buffet

No functional changes, only renaming, fixed include paths and include
guards to avoid resubmit warnings.

BUG=brillo:1161
CQ-DEPEND=CL:276521
TEST=none

Change-Id: Icacff92aef47fdd46542bc96eba3ffbb4df6241a
Reviewed-on: https://chromium-review.googlesource.com/276319
Reviewed-by: Vitaly Buka <vitalybuka@chromium.org>
Commit-Queue: Vitaly Buka <vitalybuka@chromium.org>
Tested-by: Vitaly Buka <vitalybuka@chromium.org>

buffet/privet/openssl_utils.cc

diff --git a/buffet/privet/openssl_utils.cc b/buffet/privet/openssl_utils.cc
new file mode 100644
index 0000000..17cc16f
--- /dev/null
+++ b/buffet/privet/openssl_utils.cc
@@ -0,0 +1,26 @@
+// Copyright 2014 The Chromium OS Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "buffet/privet/openssl_utils.h"
+
+#include <algorithm>
+
+#include <openssl/evp.h>
+#include <openssl/hmac.h>
+
+#include <base/logging.h>
+
+namespace privetd {
+
+chromeos::Blob HmacSha256(const chromeos::SecureBlob& key,
+                          const chromeos::Blob& data) {
+  chromeos::Blob mac(kSha256OutputSize);
+  uint32_t len = 0;
+  CHECK(HMAC(EVP_sha256(), key.data(), key.size(), data.data(),
+             data.size(), mac.data(), &len));
+  CHECK_EQ(len, kSha256OutputSize);
+  return mac;
+}
+
+}  // namespace privetd