pldmtool: File I/O & checksum options for mctpRaw

Enhance the `mctpRaw` subcommand with options to read request
data from a file (`--file-in`), write response data to a file
(`--file-out`), and append or validate checksum (`--checksum`).
These additions improve usability for large payloads and
ensure data integrity during raw MCTP transactions.

Contents of the file specified in option --file-in are appended
to the contents of the option --data.

Signed-off-by: Shirish Pargaonkar <Shirish.Pargaonkar@amd.com>

Author: spargaon

pldmtool/pldmtool.cpp

@@ -72,6 +72,31 @@ namespace
 std::vector<std::unique_ptr<CommandInterface>> commands;
 }
 
+/*
+ *   • The file size and CRC32 fields are always stored in **big-endian**
+ *     format regardless of host endianness.
+ *
+ *   • If checksum is disabled, the IC bit is cleared and the CRC32 field
+ *     is omitted.
+ *
+ *   • rawData[] is assembled in this exact order:
+ *
+ *       rawData = [Header] + [File Size] + [File Data] + [Optional CRC]
+ *
+ *   • The offsets DevHdrSize and FsField refer to the start of the file-size
+ *     field and help determine where payload sections begin.
+ *
+ *   • Header include AMD IANA number in big-endian format
+ *
+ */
+
+constexpr unsigned int DevHdrSize = 7;
+constexpr unsigned int FsField = 4;
+constexpr unsigned int CsField = 4;
+constexpr unsigned int CompCodeByte = 6;
+constexpr unsigned int MaxFileSize = 0x4000;
+constexpr unsigned int AMD_Iana_Numg = 0xe78;
+
 class MctpRawOp : public CommandInterface
 {
   public:
@@ -90,23 +115,250 @@ class MctpRawOp : public CommandInterface
         app->add_option("-d,--data", rawData, "raw MCTP data")
             ->required()
             ->expected(-3);
+        app->add_option("-i,--file-in", inFileName, "Read in the file to be sent");
+        app->add_option("-o,--file-out", outFileName, "Write out the received file");
+        app->add_flag("-c,--checksum", checksum, "Append/Validate checksum");
         app->add_flag("-p,--prealloc-tag", mctpPreAllocTag,
                       "use pre-allocated MCTP tag for this request");
-    }
-    std::pair<int, std::vector<uint8_t>> createRequestMsg() override
-
-    {
-        return {PLDM_SUCCESS, rawData};
+	app->footer(R"(Example: pldmtool mctpRaw -m 21 -e 1 \
+			--data 0x7F 0x00 0x00 0x0E 0x78 0x80 0x02 \
+			--file-in req.bin --file-out resp.bin --checksum)");
     }
 
-    void parseResponseMsg(pldm_msg* /* responsePtr */,
-                          size_t /* payloadLength */) override
-    {}
-
+    const std::string getInFileName() const {return inFileName;}
+    const std::string getOutFileName() const {return outFileName;}
+    std::pair<int, std::vector<uint8_t>> createRequestMsg() override;
+    void parseResponseMsg(pldm_msg *, size_t) override;
   private:
     std::vector<uint8_t> rawData;
+    std::string outFileName{};
+    std::string inFileName{};
+    bool checksum{false};
+
+    void appendInfile();
 };
 
+/**
+ * @brief Convert a native-endian value to big-endian.
+ *
+ * This function performs a byte swap on little-endian systems so the returned
+ * value is always in big-endian format. On big-endian systems, the value is
+ * returned unchanged.
+ *
+ * @tparam T  An integral type (e.g., uint16_t, uint32_t, uint64_t).
+ * @param value  The value to convert.
+ * @return The value represented in big-endian byte order.
+ */
+
+template <typename T>
+constexpr T convToBigEndian(T value) {
+    if constexpr (std::endian::native == std::endian::little)
+        return std::byteswap(value);
+    else
+        return value;
+}
+
+/**
+ * @brief Append the contents of the input file into the raw MCTP payload.
+ *
+ * This function performs the following steps:
+ *  - Retrieves the file size using std::filesystem.
+ *  - Reads the full file into memory.
+ *  - Appends the 4-byte big-endian file size field to @ref rawData.
+ *  - Appends the file contents to @ref rawData.
+ *  - Clears or sets the IC (Integrity Check) bit in the first byte.
+ *  - If checksum support is enabled, computes a CRC32 over the file data and
+ *    appends it in big-endian format.
+ *
+ * Exceptions during file I/O (open/read) are handled via std::ios_base::failure.
+ * Filesystem errors (e.g. file not found) are caught via std::filesystem::filesystem_error.
+ *
+ * @return void
+ *
+ * @note Files larger than 16 MiB are not expected by design.
+ * @note The function reserves enough space in @ref rawData to avoid repeated reallocations.
+ */
+
+void MctpRawOp::appendInfile()
+{
+	std::uintmax_t fSize = 0;
+	std::ifstream toDevice;
+	std::vector<uint8_t> fData;
+
+	try {
+		fSize = std::filesystem::file_size(getInFileName());
+	}
+	catch (const std::filesystem::filesystem_error& fse) {
+		std::cout << "File size error: " << fse.what() << std::endl;
+		return;
+	}
+
+	if (!fSize) {
+		std::cout << "Empty file: " << getInFileName() << std::endl;
+		return;
+	}
+
+	try {
+		toDevice.exceptions(std::ios::failbit | std::ios::badbit);
+
+		toDevice.open(getInFileName(), std::ios::binary);
+
+		fData.resize(fSize);
+
+		toDevice.read(reinterpret_cast<char*>(fData.data()), static_cast<std::streamsize>(fSize));
+	}
+	catch (const std::ios_base::failure& iose) {
+		std::cout << "In file I/O error: " << iose.what() << getInFileName() << std::endl;
+		return;
+	}
+
+	// Reserve expected additional (in) payload size
+	std::size_t reserveSize = FsField + fSize + (checksum ? CsField : 0);
+	rawData.reserve(rawData.size() + reserveSize);
+
+	uint32_t fsField = convToBigEndian(static_cast<uint32_t>(fSize));
+	auto fsValue = std::bit_cast<std::array<uint8_t, sizeof(fsField)>>(fsField);
+	rawData.insert(rawData.end(), fsValue.begin(), fsValue.end());
+
+	rawData.insert(rawData.end(), fData.begin(), fData.end());
+
+	if (checksum) {
+		uint32_t csField = convToBigEndian(static_cast<uint32_t>(pldm_edac_crc32(fData.data(), fData.size())));
+		auto csValue = std::bit_cast<std::array<uint8_t, sizeof(csField)>>(csField);
+		rawData.insert(rawData.end(), csValue.begin(), csValue.end());
+	}
+}
+
+std::pair<int, std::vector<uint8_t>> MctpRawOp::createRequestMsg()
+{
+	rawData[0] &= 0x7F; // clear the IC bit (bit 7 [0:7]) e.g. in case 0xFF, to 0x7F
+	if (checksum)
+		rawData[0] |= 0x80; // set the IC bit (bit 7 [0:7]) e.g. 0x7F to 0xFF
+
+	if (!getInFileName().empty()) // only for the -i option
+		appendInfile();
+
+	return {PLDM_SUCCESS, rawData};
+}
+
+/*
+ * @brief Parse and process a PLDM response message received over MCTP.
+ *
+ * This function validates and extracts payload information from a raw PLDM
+ * response message. The following operations are performed:
+ *
+ *   1. Validate input pointer and minimum message size.
+ *   2. Check the PLDM completion code and abort on non-zero values.
+ *   3. Verify the 4-byte IANA number (big-endian) against the expected AMD
+ *      identifier.
+ *   4. Extract and validate the reported firmware file size.
+ *   5. If an output filename is specified, extract the firmware payload data.
+ *   6. If checksum validation is enabled, compute CRC32 of the payload and
+ *      validate it against the received checksum.
+ *   7. Write the received firmware data to the specified output file.
+ *
+ * Errors and validation failures are reported to stderr and result in an
+ * immediate return without modifying any output file.
+ *
+ * @param pmsg  Pointer to the raw PLDM message buffer.
+ * @param size  Total size of the PLDM message in bytes.
+ *
+ * @note The function expects the message to contain AMD-specific vendor data
+ *       with fields in big-endian format as defined by the device protocol.
+ */
+
+void MctpRawOp::parseResponseMsg(pldm_msg *pmsg, size_t size)
+{
+	if (!pmsg)
+		return;
+
+	size += sizeof(pldm_msg_hdr);
+
+	if (size < DevHdrSize)
+		return;
+
+	const uint8_t * msg{reinterpret_cast<uint8_t *>(pmsg)};
+
+	// Extract four bytes of IANA number to verify
+	uint32_t iana;
+	memcpy(&iana, msg, sizeof(iana)); // IANA number in big endian format
+	iana = convToBigEndian(iana);
+	if (iana != AMD_Iana_Numg) {
+		std::cerr << std::showbase << std::hex << "Received IANA number: " << iana << " does not match with: " << AMD_Iana_Numg << std::endl;
+		return;
+	}
+
+	// Check Completion Code (byte)
+	if (msg[CompCodeByte] != 0) {
+		std::cerr << "Non-zero completion code: " << msg[CompCodeByte] << std::endl;
+		return;
+	}
+
+	if (size < (DevHdrSize + FsField))
+		return;
+
+	// Extract four bytes to obtain the received file size
+	uint32_t fSize;
+
+	std::memcpy(&fSize, msg + DevHdrSize, sizeof(fSize)); // File size is in Big endian format as per spec
+	fSize = convToBigEndian(fSize);
+
+	try {
+		if (fSize > MaxFileSize)
+			throw std::runtime_error("Invalid file size in bytes: " + std::to_string(fSize));
+	}
+	catch(const std::runtime_error & e) {
+		std::cout << e.what() << std::endl;
+		return;
+	}
+
+	// If -o option is not specified, nothing to write to
+	if (getOutFileName().empty())
+		return;
+
+	if (size < (DevHdrSize + FsField + fSize)) {
+		std::cerr << "Received response of " << size << " bytes shorter than expected size of " << ((DevHdrSize + FsField + fSize)) << std::endl;
+		return;
+	}
+
+	std::vector<uint8_t> fData{msg + DevHdrSize + FsField, msg + DevHdrSize + FsField + fSize};
+
+	if (checksum) {
+		if (size < (DevHdrSize + FsField + fSize + CsField)) {
+			std::cerr << "Received response of " << size << " bytes does not contain checksum" << std::endl;
+			return;
+		}
+
+		// Calculate checksum
+		const uint32_t crc = pldm_edac_crc32(fData.data(), fData.size());
+
+		// Extract four bytes of checksum
+		uint32_t checkSum;
+
+		std::memcpy(&checkSum, msg + DevHdrSize + FsField + fSize, sizeof(checkSum)); // Checksum is in Big endian format as per spec
+		checkSum = convToBigEndian(checkSum);
+
+		if (crc != checkSum) {
+			std::cerr << std::showbase << std::hex << "CRC: " << crc << " does not match the received CRC: " << checkSum << std::endl;
+			// return;
+		}
+	}
+
+	std::ofstream fromDevice;
+
+	try {
+		fromDevice.exceptions(std::ios::failbit | std::ios::badbit);
+
+		fromDevice.open(getOutFileName(), std::ios::binary);
+
+		fromDevice.write(reinterpret_cast<const char*>(fData.data()), fData.size());
+	}
+	catch (const std::ios_base::failure& iose) {
+		std::cout << "Out file I/O error: " << iose.what() << getOutFileName() << std::endl;
+		return;
+	}
+}
+
 void registerCommand(CLI::App& app)
 {
     auto mctpRaw = app.add_subcommand(