1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
|
/*
* (C) 2019 by Stéphane Veyret <sveyret@gmail.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published
* by the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*/
#include <stdlib.h>
#include <time.h>
#include <string.h>
#include <stddef.h> /* for offsetof */
#include <netinet/in.h>
#include <netinet/ip.h>
#include <netinet/tcp.h>
#include <arpa/inet.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <errno.h>
#include <linux/netfilter.h>
#include <linux/netfilter/nfnetlink.h>
#include <linux/netfilter/nf_tables.h>
#include <libmnl/libmnl.h>
#include <libnftnl/rule.h>
#include <libnftnl/expr.h>
static uint16_t parse_family(char *str, const char *option)
{
if (strcmp(str, "ip") == 0)
return NFPROTO_IPV4;
else if (strcmp(str, "ip6") == 0)
return NFPROTO_IPV6;
else if (strcmp(str, "inet") == 0)
return NFPROTO_INET;
else if (strcmp(str, "arp") == 0)
return NFPROTO_INET;
fprintf(stderr, "Unknown %s: ip, ip6, inet, arp\n", option);
exit(EXIT_FAILURE);
}
static void add_ct_expect(struct nftnl_rule *r, const char *obj_name)
{
struct nftnl_expr *e;
e = nftnl_expr_alloc("objref");
if (e == NULL) {
perror("expr objref oom");
exit(EXIT_FAILURE);
}
nftnl_expr_set_str(e, NFTNL_EXPR_OBJREF_IMM_NAME, obj_name);
nftnl_expr_set_u32(e, NFTNL_EXPR_OBJREF_IMM_TYPE, NFT_OBJECT_CT_EXPECT);
nftnl_rule_add_expr(r, e);
}
static struct nftnl_rule *setup_rule(uint8_t family, const char *table,
const char *chain, const char *handle,
const char *obj_name)
{
struct nftnl_rule *r = NULL;
uint64_t handle_num;
r = nftnl_rule_alloc();
if (r == NULL) {
perror("OOM");
exit(EXIT_FAILURE);
}
nftnl_rule_set_str(r, NFTNL_RULE_TABLE, table);
nftnl_rule_set_str(r, NFTNL_RULE_CHAIN, chain);
nftnl_rule_set_u32(r, NFTNL_RULE_FAMILY, family);
if (handle != NULL) {
handle_num = atoll(handle);
nftnl_rule_set_u64(r, NFTNL_RULE_POSITION, handle_num);
}
add_ct_expect(r, obj_name);
return r;
}
int main(int argc, char *argv[])
{
char buf[MNL_SOCKET_BUFFER_SIZE];
struct mnl_nlmsg_batch *batch;
uint32_t seq = time(NULL);
struct mnl_socket *nl;
struct nftnl_rule *r;
struct nlmsghdr *nlh;
uint8_t family;
int ret;
if (argc < 5 || argc > 6) {
fprintf(stderr,
"Usage: %s <family> <table> <chain> [<handle>] <name>\n",
argv[0]);
exit(EXIT_FAILURE);
}
family = parse_family(argv[1], "family");
if (argc < 6)
r = setup_rule(family, argv[2], argv[3], NULL, argv[4]);
else
r = setup_rule(family, argv[2], argv[3], argv[4], argv[5]);
nl = mnl_socket_open(NETLINK_NETFILTER);
if (nl == NULL) {
perror("mnl_socket_open");
exit(EXIT_FAILURE);
}
if (mnl_socket_bind(nl, 0, MNL_SOCKET_AUTOPID) < 0) {
perror("mnl_socket_bind");
exit(EXIT_FAILURE);
}
batch = mnl_nlmsg_batch_start(buf, sizeof(buf));
nftnl_batch_begin(mnl_nlmsg_batch_current(batch), seq++);
mnl_nlmsg_batch_next(batch);
nlh = nftnl_nlmsg_build_hdr(mnl_nlmsg_batch_current(batch),
NFT_MSG_NEWRULE,
nftnl_rule_get_u32(r, NFTNL_RULE_FAMILY),
NLM_F_APPEND | NLM_F_CREATE | NLM_F_ACK,
seq++);
nftnl_rule_nlmsg_build_payload(nlh, r);
nftnl_rule_free(r);
mnl_nlmsg_batch_next(batch);
nftnl_batch_end(mnl_nlmsg_batch_current(batch), seq++);
mnl_nlmsg_batch_next(batch);
ret = mnl_socket_sendto(nl, mnl_nlmsg_batch_head(batch),
mnl_nlmsg_batch_size(batch));
if (ret == -1) {
perror("mnl_socket_sendto");
exit(EXIT_FAILURE);
}
mnl_nlmsg_batch_stop(batch);
ret = mnl_socket_recvfrom(nl, buf, sizeof(buf));
if (ret == -1) {
perror("mnl_socket_recvfrom");
exit(EXIT_FAILURE);
}
ret = mnl_cb_run(buf, ret, 0, mnl_socket_get_portid(nl), NULL, NULL);
if (ret < 0) {
perror("mnl_cb_run");
exit(EXIT_FAILURE);
}
mnl_socket_close(nl);
return EXIT_SUCCESS;
}
|
