nfct-mnl-get.c
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <time.h>
#include <arpa/inet.h>
#include <libmnl/libmnl.h>
#include <libnetfilter_conntrack/libnetfilter_conntrack.h>
#include <linux/netfilter/nf_conntrack_tcp.h>
static int data_cb(const struct nlmsghdr *nlh, void *data)
{
struct nf_conntrack *ct;
char buf[4096];
ct = nfct_new();
if (ct == NULL)
return MNL_CB_OK;
nfct_nlmsg_parse(nlh, ct);
nfct_snprintf(buf, sizeof(buf), ct, NFCT_T_UNKNOWN, NFCT_O_DEFAULT, 0);
printf("%s\n", buf);
nfct_destroy(ct);
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;
struct nf_conntrack *ct;
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;
nlh->nlmsg_flags = NLM_F_REQUEST|NLM_F_ACK;
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;
ct = nfct_new();
if (ct == NULL) {
perror("nfct_new");
return 0;
}
nfct_set_attr_u8(ct, ATTR_L3PROTO, AF_INET);
nfct_set_attr_u32(ct, ATTR_IPV4_SRC, inet_addr("1.1.1.1"));
nfct_set_attr_u32(ct, ATTR_IPV4_DST, inet_addr("2.2.2.2"));
nfct_set_attr_u8(ct, ATTR_L4PROTO, IPPROTO_TCP);
nfct_set_attr_u16(ct, ATTR_PORT_SRC, htons(20));
nfct_set_attr_u16(ct, ATTR_PORT_DST, htons(10));
ret = nfct_nlmsg_build(nlh, ct);
if (ret == -1) {
perror("nfct_nlmsg_build");
exit(EXIT_FAILURE);
}
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;
}
nfct_set_attr_u32
void nfct_set_attr_u32(struct nf_conntrack *ct, const enum nf_conntrack_attr type, uint32_t value)
Definition conntrack/api.c:439
nfct_destroy
void nfct_destroy(struct nf_conntrack *ct)
Definition conntrack/api.c:93
nfct_set_attr_u16
void nfct_set_attr_u16(struct nf_conntrack *ct, const enum nf_conntrack_attr type, uint16_t value)
Definition conntrack/api.c:426
nfct_set_attr_u8
void nfct_set_attr_u8(struct nf_conntrack *ct, const enum nf_conntrack_attr type, uint8_t value)
Definition conntrack/api.c:413
nfct_snprintf
int nfct_snprintf(char *buf, unsigned int size, const struct nf_conntrack *ct, const unsigned int msg_type, const unsigned int out_type, const unsigned int out_flags)
Definition conntrack/api.c:1113
nfct_new
struct nf_conntrack * nfct_new(void)
Definition conntrack/api.c:76