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