Add packed-c protocol support for crypto service
To provide a lightweight parameter encoding that is aligned to
conventions used by SCMI, the packed-c parameter serialization has
been added to the crypto service. This builds on generic
components that allow other packed-c service access protocols
to be added easily. Service level tests have been extended to
use both protobuf and packed-c clients.
Signed-off-by: julhal01 <julian.hall@arm.com>
Change-Id: I9279b0814bcc9cf6c4aa4e30629e2f46f2df4c23
diff --git a/components/common/tlv/tlv.c b/components/common/tlv/tlv.c
new file mode 100644
index 0000000..1308832
--- /dev/null
+++ b/components/common/tlv/tlv.c
@@ -0,0 +1,99 @@
+/*
+ * Copyright (c) 2020-2021, Arm Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include "tlv.h"
+#include <string.h>
+
+size_t tlv_required_space(size_t length)
+{
+ return TLV_HDR_LEN + length;
+}
+
+void tlv_iterator_begin(struct tlv_iterator *iter, uint8_t *buf, size_t bufsize)
+{
+ iter->pos = buf;
+ iter->limit = &buf[bufsize];
+
+ /* Defend against overflow */
+ if (iter->limit < buf) iter->limit = buf;
+
+ /* Used to enforce ascending tag order when encoding */
+ iter->prev_tag = 0;
+}
+
+void tlv_const_iterator_begin(struct tlv_const_iterator *iter, const uint8_t *buf, size_t bufsize)
+{
+ iter->pos = buf;
+ iter->limit = &buf[bufsize];
+
+ /* Defend against overflow */
+ if (iter->limit < buf) iter->limit = buf;
+}
+
+bool tlv_encode(struct tlv_iterator *iter, const struct tlv_record *input)
+{
+ bool success = false;
+ size_t required_space = tlv_required_space(input->length);
+ size_t available_space = iter->limit - iter->pos;
+
+ if (required_space <= available_space && input->tag >= iter->prev_tag) {
+
+ iter->pos[TLV_TAG_OFFSET + 0] = (uint8_t)(input->tag >> 8);
+ iter->pos[TLV_TAG_OFFSET + 1] = (uint8_t)(input->tag);
+ iter->pos[TLV_LENGTH_OFFSET + 0] = (uint8_t)(input->length >> 8);
+ iter->pos[TLV_LENGTH_OFFSET + 1] = (uint8_t)(input->length);
+
+ memcpy(&iter->pos[TLV_VALUE_OFFSET], input->value, input->length);
+
+ iter->pos += required_space;
+ iter->prev_tag = input->tag;
+ success = true;
+ }
+
+ return success;
+}
+
+bool tlv_decode(struct tlv_const_iterator *iter, struct tlv_record *output)
+{
+ bool success = false;
+ size_t max_space = iter->limit - iter->pos;
+
+ if (max_space >= TLV_HDR_LEN) {
+
+ size_t record_len;
+ output->tag = (iter->pos[TLV_TAG_OFFSET + 0] << 8) | iter->pos[TLV_TAG_OFFSET + 1];
+ output->length = (iter->pos[TLV_LENGTH_OFFSET + 0] << 8) | iter->pos[TLV_LENGTH_OFFSET + 1];
+ output->value = &iter->pos[TLV_VALUE_OFFSET];
+
+ record_len = output->length + TLV_HDR_LEN;
+
+ if (record_len <= max_space) {
+
+ iter->pos += record_len;
+ success = true;
+ }
+ }
+
+ return success;
+}
+
+bool tlv_find_decode(struct tlv_const_iterator *iter, uint16_t tag, struct tlv_record *output)
+{
+ while (tlv_decode(iter, output)) {
+
+ if (output->tag == tag) {
+ /* Found a record */
+ return true;
+ }
+ else if (output->tag > tag) {
+ /* Iterated beyond the expected parameter */
+ return false;
+ }
+ }
+
+ /* Reached the end of the buffer without finding a record with the requested tag */
+ return false;
+}