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conntrack tool not work. maybe libnfnetlink problem

Discussion in 'ASUS AC Routers & Adapters' started by ticty, Sep 20, 2018.

  1. ticty

    ticty New Around Here

    Sep 20, 2018
    I have a RT-AC68U router and need to flush nat conntrack for some reasons.
    I tried compiled conntrack tool and it does not work.
    I have noticed that there exist libnfnetlink in router, so I tried below code to do a test:

    #include "libnfnetlink/libnfnetlink.h"
    #include <linux/netfilter/nfnetlink_conntrack.h>
    #include <stdio.h>
    #include <string.h>
    #include <errno.h>

    int main()
    struct nfnl_handle *h = NULL;
    struct nfnl_subsys_handle *ssh = NULL;

    h = nfnl_open();
    if(!h) {
    printf("nfnl_open fail: %s\n", strerror(errno));
    return -1;

    ssh = nfnl_subsys_open(h, NFNL_SUBSYS_CTNETLINK, IPCTNL_MSG_MAX, 0);
    if(!ssh) {
    printf("nfnl_subsys_open fail: %s\n", strerror(errno));
    return -1;

    union {
    char buffer[4096];
    struct nfnlhdr req;
    } u;

    memset(&u, 0, sizeof(u));
    nfnl_fill_hdr(ssh, &u.req.nlh, 0, AF_INET, 0, IPCTNL_MSG_CT_DELETE, NLM_F_REQUEST | NLM_F_ACK);

    if(nfnl_query(h, &u.req.nlh) != 0) {
    printf("nfnl_query fail: %s\n", strerror(errno));
    else {
    printf("nfnl_query success\n");

    return 0;

    nfnl_query() always return fail with error invalid arguement.
    I have try this code on another linux based router and it work.

    Anyone can help ?