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);
}