libnftnl  1.2.0
nft-chain-get.c
1 /*
2  * (C) 2012 by Pablo Neira Ayuso <pablo@netfilter.org>
3  *
4  * This program is free software; you can redistribute it and/or modify it
5  * under the terms of the GNU General Public License as published by
6  * the Free Software Foundation; either version 2 of the License, or
7  * (at your option) any later version.
8  *
9  * This software has been sponsored by Sophos Astaro <http://www.sophos.com>
10  */
11 
12 #include <stdlib.h>
13 #include <time.h>
14 #include <string.h>
15 #include <netinet/in.h>
16 
17 #include <linux/netfilter.h>
18 #include <linux/netfilter/nf_tables.h>
19 
20 #include <libmnl/libmnl.h>
21 #include <libnftnl/chain.h>
22 
23 static int table_cb(const struct nlmsghdr *nlh, void *data)
24 {
25  struct nftnl_chain *t;
26  char buf[4096];
27  uint32_t *type = data;
28 
29  t = nftnl_chain_alloc();
30  if (t == NULL) {
31  perror("OOM");
32  goto err;
33  }
34 
35  if (nftnl_chain_nlmsg_parse(nlh, t) < 0) {
36  perror("nftnl_chain_nlmsg_parse");
37  goto err_free;
38  }
39 
40  nftnl_chain_snprintf(buf, sizeof(buf), t, *type, 0);
41  printf("%s\n", buf);
42 
43 err_free:
44  nftnl_chain_free(t);
45 err:
46  return MNL_CB_OK;
47 }
48 
49 int main(int argc, char *argv[])
50 {
51  struct mnl_socket *nl;
52  char buf[MNL_SOCKET_BUFFER_SIZE];
53  struct nlmsghdr *nlh;
54  uint32_t portid, seq, type = NFTNL_OUTPUT_DEFAULT;
55  struct nftnl_chain *t = NULL;
56  int ret, family;
57 
58  seq = time(NULL);
59 
60  if (argc < 2 || argc > 5) {
61  fprintf(stderr, "Usage: %s <family> [<table> <chain>]\n",
62  argv[0]);
63  exit(EXIT_FAILURE);
64  }
65 
66  if (strcmp(argv[1], "ip") == 0)
67  family = NFPROTO_IPV4;
68  else if (strcmp(argv[1], "ip6") == 0)
69  family = NFPROTO_IPV6;
70  else if (strcmp(argv[1], "inet") == 0)
71  family = NFPROTO_INET;
72  else if (strcmp(argv[1], "bridge") == 0)
73  family = NFPROTO_BRIDGE;
74  else if (strcmp(argv[1], "arp") == 0)
75  family = NFPROTO_ARP;
76  else if (strcmp(argv[1], "unspec") == 0)
77  family = NFPROTO_UNSPEC;
78  else {
79  fprintf(stderr, "Unknown family: ip, ip6, inet, bridge, arp, unspec\n");
80  exit(EXIT_FAILURE);
81  }
82 
83  if (argc >= 4) {
84  t = nftnl_chain_alloc();
85  if (t == NULL) {
86  perror("OOM");
87  exit(EXIT_FAILURE);
88  }
89  nlh = nftnl_chain_nlmsg_build_hdr(buf, NFT_MSG_GETCHAIN, family,
90  NLM_F_ACK, seq);
91  nftnl_chain_set_str(t, NFTNL_CHAIN_TABLE, argv[2]);
92  nftnl_chain_set_str(t, NFTNL_CHAIN_NAME, argv[3]);
93  nftnl_chain_nlmsg_build_payload(nlh, t);
94  nftnl_chain_free(t);
95  } else if (argc >= 2) {
96  nlh = nftnl_chain_nlmsg_build_hdr(buf, NFT_MSG_GETCHAIN, family,
97  NLM_F_DUMP, seq);
98  }
99 
100  nl = mnl_socket_open(NETLINK_NETFILTER);
101  if (nl == NULL) {
102  perror("mnl_socket_open");
103  exit(EXIT_FAILURE);
104  }
105 
106  if (mnl_socket_bind(nl, 0, MNL_SOCKET_AUTOPID) < 0) {
107  perror("mnl_socket_bind");
108  exit(EXIT_FAILURE);
109  }
110  portid = mnl_socket_get_portid(nl);
111 
112  if (mnl_socket_sendto(nl, nlh, nlh->nlmsg_len) < 0) {
113  perror("mnl_socket_send");
114  exit(EXIT_FAILURE);
115  }
116 
117  ret = mnl_socket_recvfrom(nl, buf, sizeof(buf));
118  while (ret > 0) {
119  ret = mnl_cb_run(buf, ret, seq, portid, table_cb, &type);
120  if (ret <= 0)
121  break;
122  ret = mnl_socket_recvfrom(nl, buf, sizeof(buf));
123  }
124  if (ret == -1) {
125  perror("error");
126  exit(EXIT_FAILURE);
127  }
128  mnl_socket_close(nl);
129 
130  return EXIT_SUCCESS;
131 }