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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,247 @@ | ||
| /* SPDX-FileCopyrightText: 2022-present Artur Drogunow <[email protected]> | ||
| # | ||
| # SPDX-License-Identifier: MIT */ | ||
|
|
||
| #define PY_SSIZE_T_CLEAN | ||
| #include <Python.h> | ||
|
|
||
| #include <stdbool.h> | ||
| #include <stdint.h> | ||
|
|
||
| #include "crclib.h" | ||
| #include "util.h" | ||
|
|
||
| #define P07LENGTH_POS 8u | ||
| #define P07LENGTH_LEN 4u | ||
| #define P07COUNTER_POS 12u | ||
| #define P07COUNTER_LEN 4u | ||
| #define P07DATAID_POS 16u | ||
| #define P07DATAID_LEN 4u | ||
| #define P07CRC_POS 0u | ||
| #define P07CRC_LEN 8u | ||
|
|
||
| #define P07HEADER_LEN (P07CRC_LEN+P07LENGTH_LEN+P07COUNTER_LEN+P07DATAID_LEN) | ||
|
|
||
| uint64_t compute_p07_crc(uint8_t *data_ptr, | ||
| uint32_t length, | ||
| uint32_t offset) | ||
| { | ||
| uint64_t crc; | ||
|
|
||
| // bytes before crc bytes | ||
| uint32_t crc_offset = (uint32_t)(offset + P07CRC_POS); | ||
| crc = Crc_CalculateCRC64(data_ptr, crc_offset, CRC64_INITIAL_VALUE, true); | ||
|
|
||
| // bytes after crc bytes, if any | ||
| if (offset + P07CRC_POS + P07CRC_LEN < length){ | ||
| uint32_t second_part_offset = offset + P07CRC_POS + P07CRC_LEN; | ||
| uint8_t *second_part_ptr = data_ptr + second_part_offset; | ||
| uint32_t second_part_len = length - (uint32_t)(offset + P07CRC_POS + P07CRC_LEN); | ||
| crc = Crc_CalculateCRC64(second_part_ptr, second_part_len, crc, false); | ||
| } | ||
| return crc; | ||
| } | ||
|
|
||
| PyDoc_STRVAR(e2e_p07_protect_doc, | ||
| "e2e_p07_protect(data: bytearray, length: int, data_id: int, *, offset: int = 0, increment_counter: bool = True) -> None \n" | ||
| "Calculate CRC inplace according to AUTOSAR E2E Profile 7. \n" | ||
| "\n" | ||
| ":param bytearray data: \n" | ||
| " Mutable `bytes-like object <https://docs.python.org/3/glossary.html#term-bytes-like-object>`_.\n" | ||
| ":param int length: \n" | ||
| " Number of data bytes which are considered for CRC calculation. `length` must fulfill \n" | ||
| " the following condition: ``20 <= length <= len(data)`` \n" | ||
| ":param int data_id: \n" | ||
| " A unique identifier which is used to protect against masquerading. The `data_id` is a 32bit unsigned integer. \n" | ||
| ":param int offset: \n" | ||
| " Byte offset of the E2E header. \n" | ||
| ":param bool increment_counter: \n" | ||
| " If `True` the counter will be incremented before calculating the CRC. \n"); | ||
|
|
||
| static PyObject * | ||
| py_e2e_p07_protect(PyObject *module, | ||
| PyObject *args, | ||
| PyObject *kwargs) | ||
| { | ||
| Py_buffer data; | ||
| unsigned long length; | ||
| unsigned long data_id; | ||
| unsigned long offset = 0; | ||
| int increment = true; | ||
|
|
||
| static char *kwlist[] = { | ||
| "data", | ||
| "length", | ||
| "data_id", | ||
| "offset", | ||
| "increment_counter", | ||
| NULL}; | ||
|
|
||
| if (!PyArg_ParseTupleAndKeywords(args, kwargs, "y*kk|$kp:e2e_p07_protect", | ||
| kwlist, &data, &length, &data_id, &offset, &increment)) | ||
| { | ||
| return NULL; | ||
| } | ||
| if (data.readonly) | ||
| { | ||
| PyErr_SetString(PyExc_ValueError, "\"data\" must be mutable. Use a bytearray or any object that implements the buffer protocol."); | ||
| goto error; | ||
| } | ||
| if (data.len < P07HEADER_LEN) | ||
| { | ||
| PyErr_SetString(PyExc_ValueError, "The length of bytearray \"data\" must be greater than or equal to 20."); | ||
| goto error; | ||
| } | ||
| if (length < P07HEADER_LEN || length > data.len) | ||
| { | ||
| PyErr_SetString(PyExc_ValueError, "Parameter \"length\" must fulfill the following condition: 20 <= length <= len(data)."); | ||
| goto error; | ||
| } | ||
| if (offset > data.len - P07HEADER_LEN) | ||
| { | ||
| PyErr_SetString(PyExc_ValueError, "Argument \"offset\" invalid."); | ||
| goto error; | ||
| } | ||
|
|
||
| uint8_t *data_ptr = (uint8_t *)data.buf; | ||
|
|
||
| // write length | ||
| uint32_to_bigendian(data_ptr + offset + P07LENGTH_POS, length); | ||
|
|
||
| // increment counter | ||
| if (increment) { | ||
| uint32_t counter = bigendian_to_uint32(data_ptr + offset + P07COUNTER_POS); | ||
| counter += 1; | ||
| uint32_to_bigendian(data_ptr + offset + P07COUNTER_POS, counter); | ||
| } | ||
|
|
||
| // write data_id | ||
| uint32_to_bigendian(data_ptr + offset + P07DATAID_POS, data_id); | ||
|
|
||
| // calculate CRC | ||
| uint64_t crc = compute_p07_crc(data_ptr, length, offset); | ||
| uint64_to_bigendian(data_ptr + offset + P07CRC_POS, crc); | ||
|
|
||
| PyBuffer_Release(&data); | ||
|
|
||
| Py_RETURN_NONE; | ||
|
|
||
| error: | ||
| PyBuffer_Release(&data); | ||
| return NULL; | ||
| } | ||
|
|
||
| PyDoc_STRVAR(e2e_p07_check_doc, | ||
| "e2e_p07_check(data: bytes, length: int, data_id: int, *, offset: int = 0) -> bool \n" | ||
| "Return ``True`` if CRC is correct according to AUTOSAR E2E Profile 7. \n" | ||
| "\n" | ||
| ":param data: \n" | ||
| " `bytes-like object <https://docs.python.org/3/glossary.html#term-bytes-like-object>`_. \n" | ||
| ":param length: \n" | ||
| " Data byte count over which the CRC must be calculated. `length` must fulfill \n" | ||
| " the following condition: ``20 <= length <= len(data)`` \n" | ||
| ":param int data_id: \n" | ||
| " A unique identifier which is used to protect against masquerading. The `data_id` is a 32bit unsigned integer. \n" | ||
| ":param int offset: \n" | ||
| " Byte offset of the E2E header. \n" | ||
| ":return:\n" | ||
| " `True` if CRC is valid, otherwise return `False`"); | ||
|
|
||
| static PyObject * | ||
| py_e2e_p07_check(PyObject *module, | ||
| PyObject *args, | ||
| PyObject *kwargs) | ||
| { | ||
| Py_buffer data; | ||
| unsigned long length; | ||
| unsigned long data_id; | ||
| unsigned long offset = 0; | ||
|
|
||
| static char *kwlist[] = { | ||
| "data", | ||
| "length", | ||
| "data_id", | ||
| "offset", | ||
| NULL}; | ||
|
|
||
| if (!PyArg_ParseTupleAndKeywords(args, kwargs, "y*kk|$k:e2e_p07_check", | ||
| kwlist, &data, &length, &data_id, &offset)) | ||
| { | ||
| return NULL; | ||
| } | ||
| if (data.len < P07HEADER_LEN) | ||
| { | ||
| PyErr_SetString(PyExc_ValueError, "The length of bytearray \"data\" must be greater or equal to 20."); | ||
| goto error; | ||
| } | ||
| if (length < P07HEADER_LEN || length > data.len) | ||
| { | ||
| PyErr_SetString(PyExc_ValueError, "Parameter \"length\" must fulfill the following condition: 20 <= length <= len(data)."); | ||
| goto error; | ||
| } | ||
| if (offset > data.len - P07HEADER_LEN) | ||
| { | ||
| PyErr_SetString(PyExc_ValueError, "Argument \"offset\" invalid."); | ||
| goto error; | ||
| } | ||
|
|
||
| uint8_t *data_ptr = (uint8_t *)data.buf; | ||
|
|
||
| // read length | ||
| uint32_t length_actual = bigendian_to_uint32(data_ptr + offset + P07LENGTH_POS); | ||
|
|
||
| // read data_id | ||
| uint32_t data_id_actual = bigendian_to_uint32(data_ptr + offset + P07DATAID_POS); | ||
|
|
||
| // read crc | ||
| uint64_t crc_actual = bigendian_to_uint64(data_ptr + offset + P07CRC_POS); | ||
|
|
||
| // calculate CRC | ||
| uint64_t crc = compute_p07_crc(data_ptr, length, offset); | ||
|
|
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| PyBuffer_Release(&data); | ||
|
|
||
| if ((length_actual == length) && (data_id_actual == data_id) && (crc_actual == crc)) | ||
| { | ||
| Py_RETURN_TRUE; | ||
| } | ||
| else | ||
| { | ||
| Py_RETURN_FALSE; | ||
| } | ||
|
|
||
| error: | ||
| PyBuffer_Release(&data); | ||
| return NULL; | ||
| } | ||
|
|
||
| static struct PyMethodDef methods[] = { | ||
| {"e2e_p07_protect", | ||
| (PyCFunction)py_e2e_p07_protect, | ||
| METH_VARARGS | METH_KEYWORDS, | ||
| e2e_p07_protect_doc}, | ||
| {"e2e_p07_check", | ||
| (PyCFunction)py_e2e_p07_check, | ||
| METH_VARARGS | METH_KEYWORDS, | ||
| e2e_p07_check_doc}, | ||
| {NULL} // sentinel | ||
| }; | ||
|
|
||
| static PyModuleDef module = { | ||
| PyModuleDef_HEAD_INIT, | ||
| .m_name = "e2e.p07", | ||
| .m_doc = "", | ||
| .m_size = -1, | ||
| .m_methods = methods}; | ||
|
|
||
| PyMODINIT_FUNC PyInit_p07(void) | ||
| { | ||
|
|
||
| PyObject *module_p; | ||
| module_p = PyModule_Create(&module); | ||
|
|
||
| if (module_p == NULL) | ||
| return (NULL); | ||
|
|
||
| return (module_p); | ||
| } |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,11 @@ | ||
| def e2e_p07_protect( | ||
| data: bytearray, | ||
| length: int, | ||
| data_id: int, | ||
| *, | ||
| offset: int = 0, | ||
| increment_counter: bool = True, | ||
| ) -> None: ... | ||
| def e2e_p07_check( | ||
| data: bytes, length: int, data_id: int, *, offset: int = 0 | ||
| ) -> bool: ... |
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