ipv6_addr.c

#include <arpa/inet.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>

#include <sys/types.h>
#include <unistd.h>
#include <netinet/in.h>

// gcc -o ipv6_addr ipv6_addr.c -std=c99
int main(int argc, char **argv)
{
	char *ipv6_net = NULL;
	char *mac_addr = NULL;

	for (int i = 1; i < argc; ++i)
	{
		if (ipv6_net == NULL)
			ipv6_net = argv[i];
		else if (mac_addr == NULL)
			mac_addr = argv[i];
	}

	if (mac_addr == NULL)
	{
		printf("Usage: %s IPV6_ADDR MAC_ADDR\n", argv[0]);
		exit(0);
	}

	struct in6_addr ipv6_net_s;
	if (inet_pton(AF_INET6, ipv6_net, &ipv6_net_s) != 1)
	{
		fprintf(stderr, "Invalid ipv6 address: %s\n", ipv6_net);
		exit(1);
	}

	unsigned int mac[6];
	memset(&mac, 0, sizeof(int) * 6);

	sscanf(mac_addr, "%x:%x:%x:%x:%x:%x", mac, mac + 1, mac + 2, mac + 3, mac + 4, mac + 5);

	ipv6_net_s.s6_addr[8] = mac[0] ^ 2;
	ipv6_net_s.s6_addr[9] = mac[1];
	ipv6_net_s.s6_addr[10] = mac[2];
	ipv6_net_s.s6_addr[11] = 0xff;
	ipv6_net_s.s6_addr[12] = 0xfe;
	ipv6_net_s.s6_addr[13] = mac[3];
	ipv6_net_s.s6_addr[14] = mac[4];
	ipv6_net_s.s6_addr[15] = mac[5];

	char result[INET6_ADDRSTRLEN];
	inet_ntop(AF_INET6, &ipv6_net_s, result, INET6_ADDRSTRLEN);

	printf("%s\n", result);
}