parse_macaddr

parse_macaddr.c

#include <string.h>
#include <stdio.h>

static unsigned char b[6];

#include <assert.h>
#if !defined(__KERNEL__)
#define BUG_ON(cond) assert(!(cond))
#endif

void parse_macaddr(unsigned char b[6], const char *s)
{
	const char *ptr = s;
	int pos = 0;
	do {
		char tmp;
		char tmpstr[3];
		sscanf(ptr, "%3[0-9a-z]", &tmpstr);
		sscanf(tmpstr, "%02hhx", &tmp);
		BUG_ON(!(tmpstr[0] >= '0' && tmpstr[0] <= '9' ||
			 tmpstr[0] >= 'a' && tmpstr[0] <= 'f'));
		BUG_ON(!(tmpstr[1] >= '0' && tmpstr[1] <= '9' ||
			 tmpstr[1] >= 'a' && tmpstr[1] <= 'f'));
		BUG_ON(pos >= 6);
		b[pos++] = tmp;
		ptr = strchr(ptr+1, ':');
		if (ptr) ptr++;
	} while (ptr);
}

int main(int argc, char **argv)
{
	assert(argc > 1);
	parse_macaddr(b, argv[1]);
	int i;
	for (i = 0; i < sizeof(b); i++)
		printf("%02x:", b[i]);
	putchar('\n');
	return 0;
}