libnetfilter_cthelper  1.0.0
nfct-helper-get.c
1 /* This example is in the public domain. */
2 #include <stdlib.h>
3 #include <string.h>
4 #include <time.h>
5 #include <libmnl/libmnl.h>
6 #include <libnetfilter_cthelper/libnetfilter_cthelper.h>
7 
8 static int nfct_helper_cb(const struct nlmsghdr *nlh, void *data)
9 {
10  struct nfct_helper *nfct_helper;
11  char buf[4096];
12 
13  nfct_helper = nfct_helper_alloc();
14  if (nfct_helper == NULL) {
15  perror("OOM");
16  goto err;
17  }
18 
19  if (nfct_helper_nlmsg_parse_payload(nlh, nfct_helper) < 0) {
20  perror("nfct_helper_parse_nl_msg");
21  goto err_free;
22  }
23 
24  nfct_helper_snprintf(buf, sizeof(buf), nfct_helper, 0, 0);
25  printf("%s\n", buf);
26 
27 err_free:
28  nfct_helper_free(nfct_helper);
29 err:
30  return MNL_CB_OK;
31 }
32 
33 int main(int argc, char *argv[])
34 {
35  struct mnl_socket *nl;
36  char buf[MNL_SOCKET_BUFFER_SIZE];
37  struct nlmsghdr *nlh;
38  uint32_t portid, seq;
39  int ret, full = 1;
40 
41  if (argc != 1) {
42  fprintf(stderr, "Usage: %s\n", argv[0]);
43  exit(EXIT_FAILURE);
44  }
45 
46  seq = time(NULL);
47  nlh = nfct_helper_nlmsg_build_hdr(buf, NFNL_MSG_CTHELPER_GET,
48  NLM_F_DUMP, seq);
49 
50  nl = mnl_socket_open(NETLINK_NETFILTER);
51  if (nl == NULL) {
52  perror("mnl_socket_open");
53  exit(EXIT_FAILURE);
54  }
55 
56  if (mnl_socket_bind(nl, 0, MNL_SOCKET_AUTOPID) < 0) {
57  perror("mnl_socket_bind");
58  exit(EXIT_FAILURE);
59  }
60  portid = mnl_socket_get_portid(nl);
61 
62  if (mnl_socket_sendto(nl, nlh, nlh->nlmsg_len) < 0) {
63  perror("mnl_socket_send");
64  exit(EXIT_FAILURE);
65  }
66 
67  ret = mnl_socket_recvfrom(nl, buf, sizeof(buf));
68  while (ret > 0) {
69  ret = mnl_cb_run(buf, ret, seq, portid, nfct_helper_cb, &full);
70  if (ret <= 0)
71  break;
72  ret = mnl_socket_recvfrom(nl, buf, sizeof(buf));
73  }
74  if (ret == -1) {
75  perror("error");
76  exit(EXIT_FAILURE);
77  }
78  mnl_socket_close(nl);
79 
80  return EXIT_SUCCESS;
81 }
int nfct_helper_nlmsg_parse_payload(const struct nlmsghdr *nlh, struct nfct_helper *nfct_helper)
struct nfct_helper * nfct_helper_alloc(void)
int nfct_helper_snprintf(char *buf, size_t size, struct nfct_helper *nfct_helper, unsigned int type, unsigned int flags)
struct nlmsghdr * nfct_helper_nlmsg_build_hdr(char *buf, uint8_t cmd, uint16_t flags, uint32_t seq)
void nfct_helper_free(struct nfct_helper *h)