libnftnl  1.2.9
nft-ct-helper-get.c
1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /*
3  * (C) 2012 by Pablo Neira Ayuso <pablo@netfilter.org>
4  *
5  * This software has been sponsored by Sophos Astaro <http://www.sophos.com>
6  */
7 
8 
9 #include <stdlib.h>
10 #include <time.h>
11 #include <string.h>
12 #include <netinet/in.h>
13 
14 #include <linux/netfilter.h>
15 #include <linux/netfilter/nf_tables.h>
16 
17 #include <libmnl/libmnl.h>
18 #include <libnftnl/object.h>
19 
20 static int obj_cb(const struct nlmsghdr *nlh, void *data)
21 {
22  struct nftnl_obj *t;
23  char buf[4096];
24  uint32_t *type = data;
25 
26  t = nftnl_obj_alloc();
27  if (t == NULL) {
28  perror("OOM");
29  goto err;
30  }
31 
32  if (nftnl_obj_nlmsg_parse(nlh, t) < 0) {
33  perror("nftnl_obj_nlmsg_parse");
34  goto err_free;
35  }
36 
37  nftnl_obj_snprintf(buf, sizeof(buf), t, *type, 0);
38  printf("%s\n", buf);
39 
40 err_free:
41  nftnl_obj_free(t);
42 err:
43  return MNL_CB_OK;
44 }
45 
46 int main(int argc, char *argv[])
47 {
48  struct mnl_socket *nl;
49  char buf[MNL_SOCKET_BUFFER_SIZE];
50  struct nlmsghdr *nlh;
51  uint32_t portid, seq, family;
52  struct nftnl_obj *t = NULL;
53  int ret;
54  uint32_t type = NFTNL_OUTPUT_DEFAULT;
55 
56  if (argc < 3 || argc > 5) {
57  fprintf(stderr, "%s <family> <table> [<obj>]\n",
58  argv[0]);
59  return EXIT_FAILURE;
60  }
61 
62  if (strcmp(argv[1], "ip") == 0)
63  family = NFPROTO_IPV4;
64  else if (strcmp(argv[1], "ip6") == 0)
65  family = NFPROTO_IPV6;
66  else if (strcmp(argv[1], "inet") == 0)
67  family = NFPROTO_INET;
68  else if (strcmp(argv[1], "unspec") == 0)
69  family = NFPROTO_UNSPEC;
70  else {
71  fprintf(stderr, "Unknown family: ip, ip6, inet, unspec");
72  exit(EXIT_FAILURE);
73  }
74 
75  if (argc == 3 || argc == 4) {
76  t = nftnl_obj_alloc();
77  if (t == NULL) {
78  perror("OOM");
79  exit(EXIT_FAILURE);
80  }
81  }
82 
83  seq = time(NULL);
84  nftnl_obj_set_u32(t, NFTNL_OBJ_TYPE, NFT_OBJECT_CT_HELPER);
85  if (argc < 4) {
86  nlh = nftnl_nlmsg_build_hdr(buf, NFT_MSG_GETOBJ, family,
87  NLM_F_DUMP, seq);
88  if (argc == 3) {
89  nftnl_obj_set_str(t, NFTNL_OBJ_TABLE, argv[2]);
90  nftnl_obj_nlmsg_build_payload(nlh, t);
91  nftnl_obj_free(t);
92  }
93  } else {
94  nftnl_obj_set_str(t, NFTNL_OBJ_TABLE, argv[2]);
95  nftnl_obj_set_str(t, NFTNL_OBJ_NAME, argv[3]);
96 
97  nlh = nftnl_nlmsg_build_hdr(buf, NFT_MSG_GETOBJ, family,
98  NLM_F_ACK, seq);
99  nftnl_obj_nlmsg_build_payload(nlh, t);
100  nftnl_obj_free(t);
101  }
102 
103  nl = mnl_socket_open(NETLINK_NETFILTER);
104  if (nl == NULL) {
105  perror("mnl_socket_open");
106  exit(EXIT_FAILURE);
107  }
108 
109  if (mnl_socket_bind(nl, 0, MNL_SOCKET_AUTOPID) < 0) {
110  perror("mnl_socket_bind");
111  exit(EXIT_FAILURE);
112  }
113  portid = mnl_socket_get_portid(nl);
114 
115  if (mnl_socket_sendto(nl, nlh, nlh->nlmsg_len) < 0) {
116  perror("mnl_socket_send");
117  exit(EXIT_FAILURE);
118  }
119 
120  ret = mnl_socket_recvfrom(nl, buf, sizeof(buf));
121  while (ret > 0) {
122  ret = mnl_cb_run(buf, ret, seq, portid, obj_cb, &type);
123  if (ret <= 0)
124  break;
125  ret = mnl_socket_recvfrom(nl, buf, sizeof(buf));
126  }
127  if (ret == -1) {
128  perror("error");
129  exit(EXIT_FAILURE);
130  }
131  mnl_socket_close(nl);
132 
133  return EXIT_SUCCESS;
134 }