libnetfilter_conntrack 1.1.0
nfct-mnl-get.c
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
12static int data_cb(const struct nlmsghdr *nlh, void *data)
13{
14 struct nf_conntrack *ct;
15 char buf[4096];
16
17 ct = nfct_new();
18 if (ct == NULL)
19 return MNL_CB_OK;
20
21 nfct_nlmsg_parse(nlh, ct);
22
23 nfct_snprintf(buf, sizeof(buf), ct, NFCT_T_UNKNOWN, NFCT_O_DEFAULT, 0);
24 printf("%s\n", buf);
25
26 nfct_destroy(ct);
27
28 return MNL_CB_OK;
29}
30
31int main(void)
32{
33 struct mnl_socket *nl;
34 struct nlmsghdr *nlh;
35 struct nfgenmsg *nfh;
36 char buf[MNL_SOCKET_BUFFER_SIZE];
37 unsigned int seq, portid;
38 struct nf_conntrack *ct;
39 int ret;
40
41 nl = mnl_socket_open(NETLINK_NETFILTER);
42 if (nl == NULL) {
43 perror("mnl_socket_open");
44 exit(EXIT_FAILURE);
45 }
46
47 if (mnl_socket_bind(nl, 0, MNL_SOCKET_AUTOPID) < 0) {
48 perror("mnl_socket_bind");
49 exit(EXIT_FAILURE);
50 }
51 portid = mnl_socket_get_portid(nl);
52
53 nlh = mnl_nlmsg_put_header(buf);
54 nlh->nlmsg_type = (NFNL_SUBSYS_CTNETLINK << 8) | IPCTNL_MSG_CT_GET;
55 nlh->nlmsg_flags = NLM_F_REQUEST|NLM_F_ACK;
56 nlh->nlmsg_seq = seq = time(NULL);
57
58 nfh = mnl_nlmsg_put_extra_header(nlh, sizeof(struct nfgenmsg));
59 nfh->nfgen_family = AF_INET;
60 nfh->version = NFNETLINK_V0;
61 nfh->res_id = 0;
62
63 ct = nfct_new();
64 if (ct == NULL) {
65 perror("nfct_new");
66 return 0;
67 }
68
69 nfct_set_attr_u8(ct, ATTR_L3PROTO, AF_INET);
70 nfct_set_attr_u32(ct, ATTR_IPV4_SRC, inet_addr("1.1.1.1"));
71 nfct_set_attr_u32(ct, ATTR_IPV4_DST, inet_addr("2.2.2.2"));
72
73 nfct_set_attr_u8(ct, ATTR_L4PROTO, IPPROTO_TCP);
74 nfct_set_attr_u16(ct, ATTR_PORT_SRC, htons(20));
75 nfct_set_attr_u16(ct, ATTR_PORT_DST, htons(10));
76
77 ret = nfct_nlmsg_build(nlh, ct);
78 if (ret == -1) {
79 perror("nfct_nlmsg_build");
80 exit(EXIT_FAILURE);
81 }
82
83 ret = mnl_socket_sendto(nl, nlh, nlh->nlmsg_len);
84 if (ret == -1) {
85 perror("mnl_socket_recvfrom");
86 exit(EXIT_FAILURE);
87 }
88
89 ret = mnl_socket_recvfrom(nl, buf, sizeof(buf));
90 while (ret > 0) {
91 ret = mnl_cb_run(buf, ret, seq, portid, data_cb, NULL);
92 if (ret <= MNL_CB_STOP)
93 break;
94 ret = mnl_socket_recvfrom(nl, buf, sizeof(buf));
95 }
96 if (ret == -1) {
97 perror("mnl_socket_recvfrom");
98 exit(EXIT_FAILURE);
99 }
100
101 mnl_socket_close(nl);
102
103 return 0;
104}
void nfct_set_attr_u32(struct nf_conntrack *ct, const enum nf_conntrack_attr type, uint32_t value)
void nfct_destroy(struct nf_conntrack *ct)
void nfct_set_attr_u16(struct nf_conntrack *ct, const enum nf_conntrack_attr type, uint16_t value)
void nfct_set_attr_u8(struct nf_conntrack *ct, const enum nf_conntrack_attr type, uint8_t value)
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)
struct nf_conntrack * nfct_new(void)