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/*
* MAC address manupulation utility
*
* Copyright (C) 2011 Gabor Juhos <juhosg@openwrt.org>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 as published
* by the Free Software Foundation.
*
*/
#include <stdlib.h>
#include <stdio.h>
#include <stdint.h>
#include <string.h>
#include <unistd.h>
#define MAC_ADDRESS_LEN 6
#define ERR_INVALID 1
#define ERR_IO 2
static void usage(void);
char *maccalc_name;
static int parse_mac(const char *mac_str, unsigned char *buf)
{
int t;
t = sscanf(mac_str, "%02hhx:%02hhx:%02hhx:%02hhx:%02hhx:%02hhx",
&buf[0], &buf[1], &buf[2], &buf[3], &buf[4], &buf[5]);
if (t != MAC_ADDRESS_LEN)
return ERR_INVALID;
return 0;
}
static void print_mac(unsigned char *buf)
{
printf("%02x:%02x:%02x:%02x:%02x:%02x\n",
buf[0], buf[1], buf[2], buf[3], buf[4], buf[5]);
}
static int maccalc_do_add(int argc, const char *argv[])
{
unsigned char mac[MAC_ADDRESS_LEN];
uint32_t t;
int err;
int i;
if (argc != 2) {
usage();
return ERR_INVALID;
}
err = parse_mac(argv[0], mac);
if (err)
return err;
i = atoi(argv[1]);
t = (mac[3] << 16) | (mac[4] << 8) | mac[5];
t += i;
mac[3] = (t >> 16) & 0xff;
mac[4] = (t >> 8) & 0xff;
mac[5] = t & 0xff;
print_mac(mac);
return 0;
}
static int maccalc_do_logical(int argc, const char *argv[],
unsigned char (*op)(unsigned char n1,
unsigned char n2))
{
unsigned char mac1[MAC_ADDRESS_LEN];
unsigned char mac2[MAC_ADDRESS_LEN];
int err;
int i;
if (argc != 2) {
usage();
return ERR_INVALID;
}
err = parse_mac(argv[0], mac1);
if (err)
return err;
err = parse_mac(argv[1], mac2);
if (err)
return err;
for (i = 0; i < MAC_ADDRESS_LEN; i++)
mac1[i] = op(mac1[i],mac2[i]);
print_mac(mac1);
return 0;
}
static int maccalc_do_mac2bin(int argc, const char *argv[])
{
unsigned char mac[MAC_ADDRESS_LEN];
ssize_t c;
int err;
if (argc != 1) {
usage();
return ERR_INVALID;
}
err = parse_mac(argv[0], mac);
if (err)
return err;
c = write(STDOUT_FILENO, mac, sizeof(mac));
if (c != sizeof(mac)) {
fprintf(stderr, "failed to write to stdout\n");
return ERR_IO;
}
return 0;
}
static int maccalc_do_bin2mac(int argc, const char *argv[])
{
unsigned char mac[MAC_ADDRESS_LEN];
ssize_t c;
if (argc != 0) {
usage();
return ERR_INVALID;
}
c = read(STDIN_FILENO, mac, sizeof(mac));
if (c != sizeof(mac)) {
fprintf(stderr, "failed to read from stdin\n");
return ERR_IO;
}
print_mac(mac);
return 0;
}
static unsigned char op_or(unsigned char n1, unsigned char n2)
{
return n1 | n2;
}
static int maccalc_do_or(int argc, const char *argv[])
{
return maccalc_do_logical(argc, argv, op_or);
}
static unsigned char op_and(unsigned char n1, unsigned char n2)
{
return n1 & n2;
}
static int maccalc_do_and(int argc, const char *argv[])
{
return maccalc_do_logical(argc, argv, op_and);
}
static unsigned char op_xor(unsigned char n1, unsigned char n2)
{
return n1 ^ n2;
}
static int maccalc_do_xor(int argc, const char *argv[])
{
return maccalc_do_logical(argc, argv, op_xor);
}
static void usage(void)
{
fprintf(stderr,
"Usage: %s <command>\n"
"valid commands:\n"
" add <mac> <number>\n"
" and|or|xor <mac1> <mac2>\n"
" mac2bin <mac>\n"
" bin2mac\n",
maccalc_name);
}
int main(int argc, const char *argv[])
{
int (*op)(int argc, const char *argv[]);
int ret;
maccalc_name = (char *) argv[0];
if (argc < 2) {
usage();
return EXIT_FAILURE;
}
if (strcmp(argv[1], "add") == 0) {
op = maccalc_do_add;
} else if (strcmp(argv[1], "and") == 0) {
op = maccalc_do_and;
} else if (strcmp(argv[1], "or") == 0) {
op = maccalc_do_or;
} else if (strcmp(argv[1], "xor") == 0) {
op = maccalc_do_xor;
} else if (strcmp(argv[1], "mac2bin") == 0) {
op = maccalc_do_mac2bin;
} else if (strcmp(argv[1], "bin2mac") == 0) {
op = maccalc_do_bin2mac;
} else {
fprintf(stderr, "unknown command '%s'\n", argv[1]);
usage();
return EXIT_FAILURE;
}
argc -= 2;
argv += 2;
ret = op(argc, argv);
if (ret)
return EXIT_FAILURE;
return EXIT_SUCCESS;
}
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