blob: 992dfdee4abe7819d792bd77818926aef7c46578 [file] [log] [blame]
// Copyright 2021 The Pigweed Authors
// Licensed under the Apache License, Version 2.0 (the "License"); you may not
// use this file except in compliance with the License. You may obtain a copy of
// the License at
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
// License for the specific language governing permissions and limitations under
// the License.
#include "pw_hdlc/wire_packet_parser.h"
#include "pw_bytes/endian.h"
#include "pw_checksum/crc32.h"
#include "pw_hdlc/decoder.h"
#include "pw_hdlc/internal/protocol.h"
namespace pw::hdlc {
bool WirePacketParser::Parse(ConstByteSpan packet) {
if (packet.size_bytes() < Frame::kMinSizeBytes) {
return false;
if (packet.front() != kFlag || packet.back() != kFlag) {
return false;
// Partially decode into a buffer with space only for the address and control
// fields of the frame. The decoder will verify the frame's FCS field.
std::array<std::byte, 16> buffer = {};
Decoder decoder(buffer);
Status status = Status::Unknown();
decoder.Process(packet, [&status](const Result<Frame>& result) {
status = result.status();
Result<Frame> result = Frame::Parse(buffer);
if (!result.ok()) {
return false;
address_ = result.value().address();
// RESOURCE_EXHAUSTED is expected as the buffer is too small for the packet.
return status.ok() || status.IsResourceExhausted();
} // namespace pw::hdlc