utils/conntrack_dump_filter.c

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

#include <libnetfilter_conntrack/libnetfilter_conntrack.h>

static int cb(enum nf_conntrack_msg_type type,
	      struct nf_conntrack *ct,
	      void *data)
{
	char buf[1024];

	nfct_snprintf(buf, sizeof(buf), ct, NFCT_T_UNKNOWN, NFCT_O_DEFAULT, NFCT_OF_SHOW_LAYER3 | NFCT_OF_TIMESTAMP);
	printf("%s\n", buf);

	return NFCT_CB_CONTINUE;
}

int main(void)
{
	int ret;
	struct nfct_handle *h;

	h = nfct_open(CONNTRACK, 0);
	if (!h) {
		perror("nfct_open");
		return -1;
	}
	struct nfct_filter_dump *filter_dump = nfct_filter_dump_create();
	if (filter_dump == NULL) {
		perror("nfct_filter_dump_alloc");
		return -1;
	}
	struct nfct_filter_dump_mark filter_dump_mark = {
		.val = 1,
		.mask = 0xffffffff,
	};
	nfct_filter_dump_set_attr(filter_dump, NFCT_FILTER_DUMP_MARK,
					&filter_dump_mark);
	nfct_filter_dump_set_attr_u8(filter_dump, NFCT_FILTER_DUMP_L3NUM,
					AF_INET);

	nfct_callback_register(h, NFCT_T_ALL, cb, NULL);
	ret = nfct_query(h, NFCT_Q_DUMP_FILTER, filter_dump);

	nfct_filter_dump_destroy(filter_dump);

	printf("TEST: get conntrack ");
	if (ret == -1)
		printf("(%d)(%s)\n", ret, strerror(errno));
	else
		printf("(OK)\n");

	nfct_close(h);

	ret == -1 ? exit(EXIT_FAILURE) : exit(EXIT_SUCCESS);
}