opendbc/can/common.cc

189 lines
7.1 KiB
C++

#include "common.h"
unsigned int honda_checksum(uint32_t address, const std::vector<uint8_t> &d) {
int s = 0;
while (address) { s += (address & 0xF); address >>= 4; }
for (int i = 0; i < d.size(); i++) {
uint8_t x = d[i];
if (i == d.size()-1) x >>= 4; // remove checksum
s += (x & 0xF) + (x >> 4);
}
s = 8-s;
if (address > 0x7FF) s += 3; // extended can
return s & 0xF;
}
unsigned int toyota_checksum(uint32_t address, const std::vector<uint8_t> &d) {
unsigned int s = d.size();
while (address) { s += address & 0xFF; address >>= 8; }
for (int i = 0; i < d.size() - 1; i++) { s += d[i]; }
return s & 0xFF;
}
unsigned int subaru_checksum(uint32_t address, const std::vector<uint8_t> &d) {
unsigned int s = 0;
while (address) { s += address & 0xFF; address >>= 8; }
// skip checksum in first byte
for (int i = 1; i < d.size(); i++) { s += d[i]; };
return s & 0xFF;
}
unsigned int chrysler_checksum(uint32_t address, const std::vector<uint8_t> &d) {
/* jeep chrysler canbus checksum from http://illmatics.com/Remote%20Car%20Hacking.pdf */
uint8_t checksum = 0xFF;
for (int j = 0; j < (d.size() - 1); j++) {
uint8_t shift = 0x80;
uint8_t curr = d[j];
for (int i = 0; i < 8; i++) {
uint8_t bit_sum = curr & shift;
uint8_t temp_chk = checksum & 0x80U;
if (bit_sum != 0U) {
bit_sum = 0x1C;
if (temp_chk != 0U) {
bit_sum = 1;
}
checksum = checksum << 1;
temp_chk = checksum | 1U;
bit_sum ^= temp_chk;
} else {
if (temp_chk != 0U) {
bit_sum = 0x1D;
}
checksum = checksum << 1;
bit_sum ^= checksum;
}
checksum = bit_sum;
shift = shift >> 1;
}
}
return ~checksum & 0xFF;
}
// Static lookup table for fast computation of CRC8 poly 0x2F, aka 8H2F/AUTOSAR
uint8_t crc8_lut_8h2f[256];
void gen_crc_lookup_table(uint8_t poly, uint8_t crc_lut[]) {
uint8_t crc;
int i, j;
for (i = 0; i < 256; i++) {
crc = i;
for (j = 0; j < 8; j++) {
if ((crc & 0x80) != 0)
crc = (uint8_t)((crc << 1) ^ poly);
else
crc <<= 1;
}
crc_lut[i] = crc;
}
}
void init_crc_lookup_tables() {
// At init time, set up static lookup tables for fast CRC computation.
gen_crc_lookup_table(0x2F, crc8_lut_8h2f); // CRC-8 8H2F/AUTOSAR for Volkswagen
}
unsigned int volkswagen_crc(uint32_t address, const std::vector<uint8_t> &d) {
// Volkswagen uses standard CRC8 8H2F/AUTOSAR, but they compute it with
// a magic variable padding byte tacked onto the end of the payload.
// https://www.autosar.org/fileadmin/user_upload/standards/classic/4-3/AUTOSAR_SWS_CRCLibrary.pdf
uint8_t crc = 0xFF; // Standard init value for CRC8 8H2F/AUTOSAR
// CRC the payload first, skipping over the first byte where the CRC lives.
for (int i = 1; i < d.size(); i++) {
crc ^= d[i];
crc = crc8_lut_8h2f[crc];
}
// Look up and apply the magic final CRC padding byte, which permutes by CAN
// address, and additionally (for SOME addresses) by the message counter.
uint8_t counter = d[1] & 0x0F;
switch(address) {
case 0x86: // LWI_01 Steering Angle
crc ^= (uint8_t[]){0x86,0x86,0x86,0x86,0x86,0x86,0x86,0x86,0x86,0x86,0x86,0x86,0x86,0x86,0x86,0x86}[counter];
break;
case 0x9F: // LH_EPS_03 Electric Power Steering
crc ^= (uint8_t[]){0xF5,0xF5,0xF5,0xF5,0xF5,0xF5,0xF5,0xF5,0xF5,0xF5,0xF5,0xF5,0xF5,0xF5,0xF5,0xF5}[counter];
break;
case 0xAD: // Getriebe_11 Automatic Gearbox
crc ^= (uint8_t[]){0x3F,0x69,0x39,0xDC,0x94,0xF9,0x14,0x64,0xD8,0x6A,0x34,0xCE,0xA2,0x55,0xB5,0x2C}[counter];
break;
case 0xFD: // ESP_21 Electronic Stability Program
crc ^= (uint8_t[]){0xB4,0xEF,0xF8,0x49,0x1E,0xE5,0xC2,0xC0,0x97,0x19,0x3C,0xC9,0xF1,0x98,0xD6,0x61}[counter];
break;
case 0x106: // ESP_05 Electronic Stability Program
crc ^= (uint8_t[]){0x07,0x07,0x07,0x07,0x07,0x07,0x07,0x07,0x07,0x07,0x07,0x07,0x07,0x07,0x07,0x07}[counter];
break;
case 0x117: // ACC_10 Automatic Cruise Control
crc ^= (uint8_t[]){0x16,0x16,0x16,0x16,0x16,0x16,0x16,0x16,0x16,0x16,0x16,0x16,0x16,0x16,0x16,0x16}[counter];
break;
case 0x120: // TSK_06 Drivetrain Coordinator
crc ^= (uint8_t[]){0xC4,0xE2,0x4F,0xE4,0xF8,0x2F,0x56,0x81,0x9F,0xE5,0x83,0x44,0x05,0x3F,0x97,0xDF}[counter];
break;
case 0x121: // Motor_20 Driver Throttle Inputs
crc ^= (uint8_t[]){0xE9,0x65,0xAE,0x6B,0x7B,0x35,0xE5,0x5F,0x4E,0xC7,0x86,0xA2,0xBB,0xDD,0xEB,0xB4}[counter];
break;
case 0x122: // ACC_06 Automatic Cruise Control
crc ^= (uint8_t[]){0x37,0x7D,0xF3,0xA9,0x18,0x46,0x6D,0x4D,0x3D,0x71,0x92,0x9C,0xE5,0x32,0x10,0xB9}[counter];
break;
case 0x126: // HCA_01 Heading Control Assist
crc ^= (uint8_t[]){0xDA,0xDA,0xDA,0xDA,0xDA,0xDA,0xDA,0xDA,0xDA,0xDA,0xDA,0xDA,0xDA,0xDA,0xDA,0xDA}[counter];
break;
case 0x12B: // GRA_ACC_01 Steering wheel controls for ACC
crc ^= (uint8_t[]){0x6A,0x38,0xB4,0x27,0x22,0xEF,0xE1,0xBB,0xF8,0x80,0x84,0x49,0xC7,0x9E,0x1E,0x2B}[counter];
break;
case 0x12E: // ACC_07 Automatic Cruise Control
crc ^= (uint8_t[]){0xF8,0xE5,0x97,0xC9,0xD6,0x07,0x47,0x21,0x66,0xDD,0xCF,0x6F,0xA1,0x94,0x74,0x63}[counter];
break;
case 0x187: // EV_Gearshift "Gear" selection data for EVs with no gearbox
crc ^= (uint8_t[]){0x7F,0xED,0x17,0xC2,0x7C,0xEB,0x44,0x21,0x01,0xFA,0xDB,0x15,0x4A,0x6B,0x23,0x05}[counter];
break;
case 0x30C: // ACC_02 Automatic Cruise Control
crc ^= (uint8_t[]){0x0F,0x0F,0x0F,0x0F,0x0F,0x0F,0x0F,0x0F,0x0F,0x0F,0x0F,0x0F,0x0F,0x0F,0x0F,0x0F}[counter];
break;
case 0x30F: // SWA_01 Lane Change Assist (SpurWechselAssistent)
crc ^= (uint8_t[]){0x0C,0x0C,0x0C,0x0C,0x0C,0x0C,0x0C,0x0C,0x0C,0x0C,0x0C,0x0C,0x0C,0x0C,0x0C,0x0C}[counter];
break;
case 0x324: // ACC_04 Automatic Cruise Control
crc ^= (uint8_t[]){0x27,0x27,0x27,0x27,0x27,0x27,0x27,0x27,0x27,0x27,0x27,0x27,0x27,0x27,0x27,0x27}[counter];
break;
case 0x3C0: // Klemmen_Status_01 ignition and starting status
crc ^= (uint8_t[]){0xC3,0xC3,0xC3,0xC3,0xC3,0xC3,0xC3,0xC3,0xC3,0xC3,0xC3,0xC3,0xC3,0xC3,0xC3,0xC3}[counter];
break;
case 0x65D: // ESP_20 Electronic Stability Program
crc ^= (uint8_t[]){0xAC,0xB3,0xAB,0xEB,0x7A,0xE1,0x3B,0xF7,0x73,0xBA,0x7C,0x9E,0x06,0x5F,0x02,0xD9}[counter];
break;
default: // As-yet undefined CAN message, CRC check expected to fail
printf("Attempt to CRC check undefined Volkswagen message 0x%02X\n", address);
crc ^= (uint8_t[]){0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00}[counter];
break;
}
crc = crc8_lut_8h2f[crc];
return crc ^ 0xFF; // Return after standard final XOR for CRC8 8H2F/AUTOSAR
}
unsigned int pedal_checksum(const std::vector<uint8_t> &d) {
uint8_t crc = 0xFF;
uint8_t poly = 0xD5; // standard crc8
// skip checksum byte
for (int i = d.size()-2; i >= 0; i--) {
crc ^= d[i];
for (int j = 0; j < 8; j++) {
if ((crc & 0x80) != 0) {
crc = (uint8_t)((crc << 1) ^ poly);
} else {
crc <<= 1;
}
}
}
return crc;
}