1 /* 2 * (C) Copyright 2016 3 * Olliver Schinagl <oliver@schinagl.nl> 4 * 5 * SPDX-License-Identifier: GPL-2.0+ 6 */ 7 8 #include <ctype.h> 9 #include <stdbool.h> 10 #include <stdint.h> 11 #include <stdio.h> 12 #include <stdlib.h> 13 #include <string.h> 14 #include <u-boot/crc.h> 15 16 #define ARP_HLEN 6 /* Length of hardware address */ 17 #define ARP_HLEN_ASCII (ARP_HLEN * 2) + (ARP_HLEN - 1) /* with separators */ 18 #define ARP_HLEN_LAZY (ARP_HLEN * 2) /* separatorless hardware address length */ 19 20 uint8_t nibble_to_hex(const char *nibble, bool lo) 21 { 22 return (strtol(nibble, NULL, 16) << (lo ? 0 : 4)) & (lo ? 0x0f : 0xf0); 23 } 24 25 int process_mac(const char *mac_address) 26 { 27 uint8_t ethaddr[ARP_HLEN + 1] = { 0x00 }; 28 uint_fast8_t i = 0; 29 30 while (*mac_address != '\0') { 31 char nibble[2] = { 0x00, '\n' }; /* for strtol */ 32 33 nibble[0] = *mac_address++; 34 if (isxdigit(nibble[0])) { 35 if (isupper(nibble[0])) 36 nibble[0] = tolower(nibble[0]); 37 ethaddr[i >> 1] |= nibble_to_hex(nibble, (i % 2) != 0); 38 i++; 39 } 40 } 41 42 for (i = 0; i < ARP_HLEN; i++) 43 printf("%.2x", ethaddr[i]); 44 printf("%.2x\n", crc8(0, ethaddr, ARP_HLEN)); 45 46 return 0; 47 } 48 49 void print_usage(char *cmdname) 50 { 51 printf("Usage: %s <mac_address>\n", cmdname); 52 puts("<mac_address> may be with or without separators."); 53 puts("Valid seperators are ':' and '-'."); 54 puts("<mac_address> digits are in base 16.\n"); 55 } 56 57 int main(int argc, char *argv[]) 58 { 59 if (argc < 2) { 60 print_usage(argv[0]); 61 return 1; 62 } 63 64 if (!((strlen(argv[1]) == ARP_HLEN_ASCII) || (strlen(argv[1]) == ARP_HLEN_LAZY))) { 65 puts("The MAC address is not valid.\n"); 66 print_usage(argv[0]); 67 return 1; 68 } 69 70 if (process_mac(argv[1])) { 71 puts("Failed to calculate the MAC's checksum."); 72 return 1; 73 } 74 75 return 0; 76 } 77