libnftnl 1.2.6
nft-rule-ct-helper-add.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 <stddef.h> /* for offsetof */
16#include <netinet/in.h>
17#include <netinet/ip.h>
18#include <netinet/tcp.h>
19#include <arpa/inet.h>
20#include <sys/types.h>
21#include <sys/socket.h>
22#include <errno.h>
23
24#include <linux/netfilter.h>
25#include <linux/netfilter/nfnetlink.h>
26#include <linux/netfilter/nf_tables.h>
27
28#include <libmnl/libmnl.h>
29#include <libnftnl/rule.h>
30#include <libnftnl/expr.h>
31
32static void add_ct_helper(struct nftnl_rule *r, const char *obj_name)
33{
34 struct nftnl_expr *e;
35
36 e = nftnl_expr_alloc("objref");
37 if (e == NULL) {
38 perror("expr objref oom");
39 exit(EXIT_FAILURE);
40 }
41 nftnl_expr_set_str(e, NFTNL_EXPR_OBJREF_IMM_NAME, obj_name);
42 nftnl_expr_set_u32(e, NFTNL_EXPR_OBJREF_IMM_TYPE, 3);
43
44 nftnl_rule_add_expr(r, e);
45}
46
47static struct nftnl_rule *setup_rule(uint8_t family, const char *table,
48 const char *chain, const char *handle, const char *obj_name)
49{
50 struct nftnl_rule *r = NULL;
51 uint64_t handle_num;
52
53 r = nftnl_rule_alloc();
54 if (r == NULL) {
55 perror("OOM");
56 exit(EXIT_FAILURE);
57 }
58
59 nftnl_rule_set_str(r, NFTNL_RULE_TABLE, table);
60 nftnl_rule_set_str(r, NFTNL_RULE_CHAIN, chain);
61 nftnl_rule_set_u32(r, NFTNL_RULE_FAMILY, family);
62
63 if (handle != NULL) {
64 handle_num = atoll(handle);
65 nftnl_rule_set_u64(r, NFTNL_RULE_POSITION, handle_num);
66 }
67
68 add_ct_helper(r, obj_name);
69
70 return r;
71}
72
73int main(int argc, char *argv[])
74{
75 struct mnl_socket *nl;
76 struct nftnl_rule *r;
77 struct nlmsghdr *nlh;
78 struct mnl_nlmsg_batch *batch;
79 uint8_t family;
80 char buf[MNL_SOCKET_BUFFER_SIZE];
81 uint32_t seq = time(NULL);
82 int ret;
83
84 if (argc < 5 || argc > 6) {
85 fprintf(stderr, "Usage: %s <family> <table> <chain> <name>\n", argv[0]);
86 exit(EXIT_FAILURE);
87 }
88 if (strcmp(argv[1], "ip") == 0)
89 family = NFPROTO_IPV4;
90 else if (strcmp(argv[1], "ip6") == 0)
91 family = NFPROTO_IPV6;
92 else if (strcmp(argv[1], "inet") == 0)
93 family = NFPROTO_INET;
94 else {
95 fprintf(stderr, "Unknown family: ip, ip6, inet\n");
96 exit(EXIT_FAILURE);
97 }
98
99 if (argc != 6)
100 r = setup_rule(family, argv[2], argv[3], NULL, argv[4]);
101 else
102 r = setup_rule(family, argv[2], argv[3], argv[4], argv[5]);
103
104 nl = mnl_socket_open(NETLINK_NETFILTER);
105 if (nl == NULL) {
106 perror("mnl_socket_open");
107 exit(EXIT_FAILURE);
108 }
109
110 if (mnl_socket_bind(nl, 0, MNL_SOCKET_AUTOPID) < 0) {
111 perror("mnl_socket_bind");
112 exit(EXIT_FAILURE);
113 }
114
115 batch = mnl_nlmsg_batch_start(buf, sizeof(buf));
116
117 nftnl_batch_begin(mnl_nlmsg_batch_current(batch), seq++);
118 mnl_nlmsg_batch_next(batch);
119
120 nlh = nftnl_nlmsg_build_hdr(mnl_nlmsg_batch_current(batch),
121 NFT_MSG_NEWRULE,
122 nftnl_rule_get_u32(r, NFTNL_RULE_FAMILY),
123 NLM_F_APPEND | NLM_F_CREATE | NLM_F_ACK,
124 seq++);
125 nftnl_rule_nlmsg_build_payload(nlh, r);
126 nftnl_rule_free(r);
127 mnl_nlmsg_batch_next(batch);
128
129 nftnl_batch_end(mnl_nlmsg_batch_current(batch), seq++);
130 mnl_nlmsg_batch_next(batch);
131
132 ret = mnl_socket_sendto(nl, mnl_nlmsg_batch_head(batch),
133 mnl_nlmsg_batch_size(batch));
134 if (ret == -1) {
135 perror("mnl_socket_sendto");
136 exit(EXIT_FAILURE);
137 }
138
139 mnl_nlmsg_batch_stop(batch);
140
141 ret = mnl_socket_recvfrom(nl, buf, sizeof(buf));
142 if (ret == -1) {
143 perror("mnl_socket_recvfrom");
144 exit(EXIT_FAILURE);
145 }
146
147 ret = mnl_cb_run(buf, ret, 0, mnl_socket_get_portid(nl), NULL, NULL);
148 if (ret < 0) {
149 perror("mnl_cb_run");
150 exit(EXIT_FAILURE);
151 }
152
153 mnl_socket_close(nl);
154
155 return EXIT_SUCCESS;
156}