1#include <stdio.h>
2#include <stdlib.h>
3#include <unistd.h>
4#include <time.h>
5#include <arpa/inet.h>
6
7#include <libmnl/libmnl.h>
8#include <libnetfilter_conntrack/libnetfilter_conntrack.h>
9
10#include <linux/netfilter/nf_conntrack_tcp.h>
11
12int main(void)
13{
14	struct mnl_socket *nl;
15	struct nlmsghdr *nlh;
16	struct nfgenmsg *nfh;
17	char buf[MNL_SOCKET_BUFFER_SIZE];
18	unsigned int seq, portid;
19	struct nf_conntrack *ct;
20	int ret;
21
22	nl = mnl_socket_open(NETLINK_NETFILTER);
23	if (nl == NULL) {
24		perror("mnl_socket_open");
25		exit(EXIT_FAILURE);
26	}
27
28	if (mnl_socket_bind(nl, 0, MNL_SOCKET_AUTOPID) < 0) {
29		perror("mnl_socket_bind");
30		exit(EXIT_FAILURE);
31	}
32	portid = mnl_socket_get_portid(nl);
33
34	nlh = mnl_nlmsg_put_header(buf);
35	nlh->nlmsg_type = (NFNL_SUBSYS_CTNETLINK << 8) | IPCTNL_MSG_CT_DELETE;
36	nlh->nlmsg_flags = NLM_F_REQUEST|NLM_F_ACK;
37	nlh->nlmsg_seq = seq = time(NULL);
38
39	nfh = mnl_nlmsg_put_extra_header(nlh, sizeof(struct nfgenmsg));
40	nfh->nfgen_family = AF_INET;
41	nfh->version = NFNETLINK_V0;
42	nfh->res_id = 0;
43
44	ct = nfct_new();
45	if (ct == NULL) {
46		perror("nfct_new");
47		return 0;
48	}
49
50	nfct_set_attr_u8(ct, ATTR_L3PROTO, AF_INET);
51	nfct_set_attr_u32(ct, ATTR_IPV4_SRC, inet_addr("1.1.1.1"));
52	nfct_set_attr_u32(ct, ATTR_IPV4_DST, inet_addr("2.2.2.2"));
53
54	nfct_set_attr_u8(ct, ATTR_L4PROTO, IPPROTO_TCP);
55	nfct_set_attr_u16(ct, ATTR_PORT_SRC, htons(20));
56	nfct_set_attr_u16(ct, ATTR_PORT_DST, htons(10));
57
58	nfct_nlmsg_build(nlh, ct);
59
60	ret = mnl_socket_sendto(nl, nlh, nlh->nlmsg_len);
61	if (ret == -1) {
62		perror("mnl_socket_recvfrom");
63		exit(EXIT_FAILURE);
64	}
65
66	ret = mnl_socket_recvfrom(nl, buf, sizeof(buf));
67	while (ret > 0) {
68		ret = mnl_cb_run(buf, ret, seq, portid, NULL, NULL);
69		if (ret <= MNL_CB_STOP)
70			break;
71		ret = mnl_socket_recvfrom(nl, buf, sizeof(buf));
72	}
73	if (ret == -1) {
74		perror("mnl_socket_recvfrom");
75		exit(EXIT_FAILURE);
76	}
77
78	mnl_socket_close(nl);
79
80	return 0;
81}
82