ip masking basic sample

membyte.c

#include <stdio.h>
#include <stdlib.h>

int membyte(unsigned char *b1, unsigned char *b2, unsigned char *b3, int len)
{
  unsigned char *tmp = malloc(len);
	printf("\n");
	int i = 0;
	for (i = 0; i < len; i++) {
		printf("----\n");
		printf("^: 0x%.02X\n", tmp[i] = b1[i] ^ b2[i]);
		printf("|: 0x%.02X\n", tmp[i] = b1[i] | b2[i]);
		printf("&: 0x%.02X\n", tmp[i] = b1[i] & b2[i]);
		printf("----\n");
	}
	
	printf("result:\n");
	
	for (i = 0; i < len; i++) {
		printf("----\n");
		printf("^: 0x%.02X\n", tmp[i] ^ b3[i]);
		printf("&: 0x%.02X\n", tmp[i] & b3[i]);
		printf("|: 0x%.02X\n", tmp[i] | b3[i]);
		printf("----\n");
	}
	
	unsigned int m = memcmp(tmp, b3, len);
	printf("cmp %.02X %d\n", m, m); // tmp[i] | b3[i]);
	printf("\n");
}

int main(int argc, char const* argv[])
{
	unsigned char buf1[4] = { 0xC0, 0xA8, 0x01, 0x42 };
	unsigned char buf2[4] = { 0xFF, 0xFF, 0xFF, 0x00 };
	unsigned char buf3[4] = { 0xC0, 0xA8, 0x01, 0x00 };
	membyte(buf1, buf2, buf3, 4);
	return 0;
}