This patch adds a little tool that takes a generic MAC address and generates a CRC byte for it. The output is the full MAC address without any separators, ready written into an EEPROM. Signed-off-by: Olliver Schinagl <o.schinagl@ultimaker.com> Signed-off-by: Olliver Schinagl <oliver@schinagl.nl> Acked-by: Joe Hershberger <joe.hershberger@ni.com>master
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/*
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* (C) Copyright 2016 |
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* Olliver Schinagl <oliver@schinagl.nl> |
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* |
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* SPDX-License-Identifier: GPL-2.0+ |
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*/ |
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#include <ctype.h> |
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#include <stdint.h> |
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#include <stdio.h> |
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#include <stdlib.h> |
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#include <string.h> |
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#include <u-boot/crc.h> |
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#define ARP_HLEN 6 /* Length of hardware address */ |
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#define ARP_HLEN_ASCII (ARP_HLEN * 2) + (ARP_HLEN - 1) /* with separators */ |
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#define ARP_HLEN_LAZY (ARP_HLEN * 2) /* separatorless hardware address length */ |
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uint8_t nibble_to_hex(const char *nibble, bool lo) |
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{ |
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return (strtol(nibble, NULL, 16) << (lo ? 0 : 4)) & (lo ? 0x0f : 0xf0); |
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} |
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int process_mac(const char *mac_address) |
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{ |
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uint8_t ethaddr[ARP_HLEN + 1] = { 0x00 }; |
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uint_fast8_t i = 0; |
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while (*mac_address != '\0') { |
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char nibble[2] = { 0x00, '\n' }; /* for strtol */ |
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nibble[0] = *mac_address++; |
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if (isxdigit(nibble[0])) { |
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if (isupper(nibble[0])) |
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nibble[0] = tolower(nibble[0]); |
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ethaddr[i >> 1] |= nibble_to_hex(nibble, (i % 2) != 0); |
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i++; |
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} |
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} |
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for (i = 0; i < ARP_HLEN; i++) |
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printf("%.2x", ethaddr[i]); |
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printf("%.2x\n", crc8(0, ethaddr, ARP_HLEN)); |
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return 0; |
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} |
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void print_usage(char *cmdname) |
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{ |
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printf("Usage: %s <mac_address>\n", cmdname); |
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puts("<mac_address> may be with or without separators."); |
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puts("Valid seperators are ':' and '-'."); |
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puts("<mac_address> digits are in base 16.\n"); |
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} |
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int main(int argc, char *argv[]) |
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{ |
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if (argc < 2) { |
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print_usage(argv[0]); |
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return 1; |
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} |
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if (!((strlen(argv[1]) == ARP_HLEN_ASCII) || (strlen(argv[1]) == ARP_HLEN_LAZY))) { |
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puts("The MAC address is not valid.\n"); |
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print_usage(argv[0]); |
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return 1; |
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} |
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if (process_mac(argv[1])) { |
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puts("Failed to calculate the MAC's checksum."); |
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return 1; |
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} |
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return 0; |
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} |
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