libnftnl 1.2.9
nft-chain-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/chain.h>
18
19static int table_cb(const struct nlmsghdr *nlh, void *data)
20{
21 struct nftnl_chain *t;
22 char buf[4096];
23 uint32_t *type = data;
24
25 t = nftnl_chain_alloc();
26 if (t == NULL) {
27 perror("OOM");
28 goto err;
29 }
30
31 if (nftnl_chain_nlmsg_parse(nlh, t) < 0) {
32 perror("nftnl_chain_nlmsg_parse");
33 goto err_free;
34 }
35
36 nftnl_chain_snprintf(buf, sizeof(buf), t, *type, 0);
37 printf("%s\n", buf);
38
39err_free:
40 nftnl_chain_free(t);
41err:
42 return MNL_CB_OK;
43}
44
45int 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, type = NFTNL_OUTPUT_DEFAULT;
51 struct nftnl_chain *t = NULL;
52 int ret, family;
53
54 seq = time(NULL);
55
56 if (argc < 2 || argc > 5) {
57 fprintf(stderr, "Usage: %s <family> [<table> <chain>]\n",
58 argv[0]);
59 exit(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], "bridge") == 0)
69 family = NFPROTO_BRIDGE;
70 else if (strcmp(argv[1], "arp") == 0)
71 family = NFPROTO_ARP;
72 else if (strcmp(argv[1], "unspec") == 0)
73 family = NFPROTO_UNSPEC;
74 else {
75 fprintf(stderr, "Unknown family: ip, ip6, inet, bridge, arp, unspec\n");
76 exit(EXIT_FAILURE);
77 }
78
79 if (argc >= 4) {
80 t = nftnl_chain_alloc();
81 if (t == NULL) {
82 perror("OOM");
83 exit(EXIT_FAILURE);
84 }
85 nlh = nftnl_nlmsg_build_hdr(buf, NFT_MSG_GETCHAIN, family,
86 NLM_F_ACK, seq);
87 nftnl_chain_set_str(t, NFTNL_CHAIN_TABLE, argv[2]);
88 nftnl_chain_set_str(t, NFTNL_CHAIN_NAME, argv[3]);
89 nftnl_chain_nlmsg_build_payload(nlh, t);
90 nftnl_chain_free(t);
91 } else if (argc >= 2) {
92 nlh = nftnl_nlmsg_build_hdr(buf, NFT_MSG_GETCHAIN, family,
93 NLM_F_DUMP, seq);
94 }
95
96 nl = mnl_socket_open(NETLINK_NETFILTER);
97 if (nl == NULL) {
98 perror("mnl_socket_open");
99 exit(EXIT_FAILURE);
100 }
101
102 if (mnl_socket_bind(nl, 0, MNL_SOCKET_AUTOPID) < 0) {
103 perror("mnl_socket_bind");
104 exit(EXIT_FAILURE);
105 }
106 portid = mnl_socket_get_portid(nl);
107
108 if (mnl_socket_sendto(nl, nlh, nlh->nlmsg_len) < 0) {
109 perror("mnl_socket_send");
110 exit(EXIT_FAILURE);
111 }
112
113 ret = mnl_socket_recvfrom(nl, buf, sizeof(buf));
114 while (ret > 0) {
115 ret = mnl_cb_run(buf, ret, seq, portid, table_cb, &type);
116 if (ret <= 0)
117 break;
118 ret = mnl_socket_recvfrom(nl, buf, sizeof(buf));
119 }
120 if (ret == -1) {
121 perror("error");
122 exit(EXIT_FAILURE);
123 }
124 mnl_socket_close(nl);
125
126 return EXIT_SUCCESS;
127}