test_filter.c

/*
 * Test for the filter API
 */

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

#include <libnetfilter_conntrack/libnetfilter_conntrack.h>

static int event_cb(enum nf_conntrack_msg_type type,
                    struct nf_conntrack *ct,
                    void *data)
{
        static int n = 0;
        char buf[1024];

        nfct_snprintf(buf, sizeof(buf), ct, type, NFCT_O_PLAIN, NFCT_OF_TIME);
        printf("%s\n", buf);

        if (++n == 10)
                return NFCT_CB_STOP;

        return NFCT_CB_CONTINUE;
}

int main(void)
{
        int i, ret;
        struct nfct_handle *h;
        struct nfct_filter *filter;

        h = nfct_open(CONNTRACK, NF_NETLINK_CONNTRACK_NEW |
                                 NF_NETLINK_CONNTRACK_UPDATE);
        if (!h) {
                perror("nfct_open");
                return 0;
        }

        filter = nfct_filter_create();
        if (!filter) {
                perror("nfct_create_filter");
                return 0;
        }

        if (nfct_filter_attach(nfct_fd(h), filter) == -1) {
                perror("nfct_filter_attach");
                return 0;
        }

        /* protocol 255 is skipped since we support up to 255 protocols max */
        for (i=0; i<IPPROTO_MAX; i++)
                nfct_filter_add_attr_u32(filter,NFCT_FILTER_L4PROTO,i);

        /* up to 127 IP addresses, above that adding is noop */
        for (i=0; i<128; i++) {
                /* BSF always wants data in host-byte order */
                struct nfct_filter_ipv4 fltr_ipv4 = {
                        .addr = ntohl(inet_addr("127.0.0.1")) + i,
                        .mask = 0xffffffff,
                };
                nfct_filter_add_attr(filter, NFCT_FILTER_SRC_IPV4, &fltr_ipv4);
        };

        if (nfct_filter_attach(nfct_fd(h), filter) == -1) {
                perror("nfct_filter_attach");
                return 0;
        }

        nfct_filter_destroy(filter);

        nfct_callback_register(h, NFCT_T_ALL, event_cb, NULL);

        ret = nfct_catch(h);
        printf("test ret=%d (%s)\n", ret, strerror(errno));
        return EXIT_SUCCESS;
}