/*
 * This example is placed in the public domain.
 * cc empty_cfg.c -lmnl -lnetfilter_log
 */

#include <stdio.h>
#include <stdlib.h>
#include <arpa/inet.h>
#include <errno.h>
#include <assert.h>

#include <linux/netfilter/nfnetlink_log.h>

#include <libmnl/libmnl.h>
#include <libnetfilter_log/libnetfilter_log.h>

int main(int argc, char *argv[])
{
	struct mnl_socket *nl;
	char buf[MNL_SOCKET_BUFFER_SIZE];
	struct nlmsghdr *nlh;
	int ret;
	unsigned int portid, qnum;

	if (argc != 2) {
		printf("Usage: %s [queue_num]\n", argv[0]);
		exit(EXIT_FAILURE);
	}
	qnum = atoi(argv[1]);

	nl = mnl_socket_open(NETLINK_NETFILTER);
	if (nl == NULL) {
		perror("mnl_socket_open");
		exit(EXIT_FAILURE);
	}

	if (mnl_socket_bind(nl, 0, MNL_SOCKET_AUTOPID) < 0) {
		perror("mnl_socket_bind");
		exit(EXIT_FAILURE);
	}
	portid = mnl_socket_get_portid(nl);

	nlh = nflog_nlmsg_put_header(buf, NFULNL_MSG_CONFIG, AF_UNSPEC, qnum);
	nlh->nlmsg_flags |= NLM_F_ACK;
	if (mnl_socket_sendto(nl, nlh, nlh->nlmsg_len) < 0) {
		perror("mnl_socket_sendto");
		exit(EXIT_FAILURE);
	}

	ret = mnl_socket_recvfrom(nl, buf, sizeof(buf));
	if (ret == -1) {
		perror("mnl_socket_recvfrom");
		exit(EXIT_FAILURE);
	}

	assert(mnl_cb_run(buf, ret, 0, portid, NULL, NULL) == MNL_CB_ERROR);
	assert(errno == ENODEV);

	mnl_socket_close(nl);

	return 0;
}