nfct-mnl-stats-cpu.c

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <time.h>
#include <arpa/inet.h>

#include <linux/netfilter/nfnetlink_conntrack.h>
#include <libmnl/libmnl.h>

static int data_attr_cb(const struct nlattr *attr, void *data)
{
        const struct nlattr **tb = data;
        int type = mnl_attr_get_type(attr);

        if (mnl_attr_type_valid(attr, CTA_STATS_MAX) < 0)
                return MNL_CB_OK;

        if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0) {
                perror("mnl_attr_validate");
                return MNL_CB_ERROR;
        }

        tb[type] = attr;
        return MNL_CB_OK;
}

static int data_cb(const struct nlmsghdr *nlh, void *data)
{
        struct nlattr *tb[CTA_STATS_MAX+1] = {};
        struct nfgenmsg *nfg = mnl_nlmsg_get_payload(nlh);
        int i;

        mnl_attr_parse(nlh, sizeof(*nfg), data_attr_cb, tb);

        for (i=0; i<CTA_STATS_MAX; i++) {
                if (tb[i])
                        printf("%08x ", ntohl(mnl_attr_get_u32(tb[i])));
        }

        printf("\n");
        return MNL_CB_OK;
}

int main(void)
{
        struct mnl_socket *nl;
        struct nlmsghdr *nlh;
        struct nfgenmsg *nfh;
        char buf[MNL_SOCKET_BUFFER_SIZE];
        unsigned int seq, portid;
        int ret;

        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 = mnl_nlmsg_put_header(buf);
        nlh->nlmsg_type = (NFNL_SUBSYS_CTNETLINK << 8) |
                          IPCTNL_MSG_CT_GET_STATS_CPU;
        nlh->nlmsg_flags = NLM_F_REQUEST|NLM_F_DUMP;
        nlh->nlmsg_seq = seq = time(NULL);

        nfh = mnl_nlmsg_put_extra_header(nlh, sizeof(struct nfgenmsg));
        nfh->nfgen_family = AF_INET;
        nfh->version = NFNETLINK_V0;
        nfh->res_id = 0;

        ret = mnl_socket_sendto(nl, nlh, nlh->nlmsg_len);
        if (ret == -1) {
                perror("mnl_socket_recvfrom");
                exit(EXIT_FAILURE);
        }

        ret = mnl_socket_recvfrom(nl, buf, sizeof(buf));
        while (ret > 0) {
                ret = mnl_cb_run(buf, ret, seq, portid, data_cb, NULL);
                if (ret <= MNL_CB_STOP)
                        break;
                ret = mnl_socket_recvfrom(nl, buf, sizeof(buf));
        }
        if (ret == -1) {
                perror("mnl_socket_recvfrom");
                exit(EXIT_FAILURE);
        }

        mnl_socket_close(nl);

        return 0;
}