libnftnl  1.2.9
nft-table-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 #include <stdlib.h>
9 #include <time.h>
10 #include <string.h>
11 #include <netinet/in.h>
12 
13 #include <linux/netfilter.h>
14 #include <linux/netfilter/nf_tables.h>
15 
16 #include <libmnl/libmnl.h>
17 #include <libnftnl/table.h>
18 
19 static int table_cb(const struct nlmsghdr *nlh, void *data)
20 {
21  struct nftnl_table *t;
22  char buf[4096];
23  uint32_t *type = data;
24 
25  t = nftnl_table_alloc();
26  if (t == NULL) {
27  perror("OOM");
28  goto err;
29  }
30 
31  if (nftnl_table_nlmsg_parse(nlh, t) < 0) {
32  perror("nftnl_table_nlmsg_parse");
33  goto err_free;
34  }
35 
36  nftnl_table_snprintf(buf, sizeof(buf), t, *type, 0);
37  printf("%s\n", buf);
38 
39 err_free:
40  nftnl_table_free(t);
41 err:
42  return MNL_CB_OK;
43 }
44 
45 int main(int argc, char *argv[])
46 {
47  struct mnl_socket *nl;
48  char buf[MNL_SOCKET_BUFFER_SIZE];
49  struct nlmsghdr *nlh;
50  uint32_t portid, seq, family;
51  struct nftnl_table *t = NULL;
52  int ret;
53  uint32_t type = NFTNL_OUTPUT_DEFAULT;
54 
55  if (argc < 2 || argc > 4) {
56  fprintf(stderr, "%s <family> [<table>]\n", argv[0]);
57  return EXIT_FAILURE;
58  }
59 
60  if (strcmp(argv[1], "ip") == 0)
61  family = NFPROTO_IPV4;
62  else if (strcmp(argv[1], "ip6") == 0)
63  family = NFPROTO_IPV6;
64  else if (strcmp(argv[1], "inet") == 0)
65  family = NFPROTO_INET;
66  else if (strcmp(argv[1], "bridge") == 0)
67  family = NFPROTO_BRIDGE;
68  else if (strcmp(argv[1], "arp") == 0)
69  family = NFPROTO_ARP;
70  else if (strcmp(argv[1], "unspec") == 0)
71  family = NFPROTO_UNSPEC;
72  else {
73  fprintf(stderr, "Unknown family: ip, ip6, inet, bridge, arp, unspec\n");
74  exit(EXIT_FAILURE);
75  }
76 
77  if (argc == 3) {
78  t = nftnl_table_alloc();
79  if (t == NULL) {
80  perror("OOM");
81  exit(EXIT_FAILURE);
82  }
83  }
84 
85  seq = time(NULL);
86  if (t == NULL) {
87  nlh = nftnl_nlmsg_build_hdr(buf, NFT_MSG_GETTABLE, family,
88  NLM_F_DUMP, seq);
89  } else {
90  nlh = nftnl_nlmsg_build_hdr(buf, NFT_MSG_GETTABLE, family,
91  NLM_F_ACK, seq);
92  nftnl_table_set_str(t, NFTNL_TABLE_NAME, argv[2]);
93  nftnl_table_nlmsg_build_payload(nlh, t);
94  nftnl_table_free(t);
95  }
96 
97  nl = mnl_socket_open(NETLINK_NETFILTER);
98  if (nl == NULL) {
99  perror("mnl_socket_open");
100  exit(EXIT_FAILURE);
101  }
102 
103  if (mnl_socket_bind(nl, 0, MNL_SOCKET_AUTOPID) < 0) {
104  perror("mnl_socket_bind");
105  exit(EXIT_FAILURE);
106  }
107  portid = mnl_socket_get_portid(nl);
108 
109  if (mnl_socket_sendto(nl, nlh, nlh->nlmsg_len) < 0) {
110  perror("mnl_socket_send");
111  exit(EXIT_FAILURE);
112  }
113 
114  ret = mnl_socket_recvfrom(nl, buf, sizeof(buf));
115  while (ret > 0) {
116  ret = mnl_cb_run(buf, ret, seq, portid, table_cb, &type);
117  if (ret <= 0)
118  break;
119  ret = mnl_socket_recvfrom(nl, buf, sizeof(buf));
120  }
121  if (ret == -1) {
122  perror("error");
123  exit(EXIT_FAILURE);
124  }
125  mnl_socket_close(nl);
126 
127  return EXIT_SUCCESS;
128 }