nft_meta.c
5.37 KB
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
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
/*
* Copyright (c) 2008-2009 Patrick McHardy <kaber@trash.net>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* Development of this code funded by Astaro AG (http://www.astaro.com/)
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/netlink.h>
#include <linux/netfilter.h>
#include <linux/netfilter/nf_tables.h>
#include <net/dst.h>
#include <net/sock.h>
#include <net/tcp_states.h> /* for TCP_TIME_WAIT */
#include <net/netfilter/nf_tables.h>
struct nft_meta {
enum nft_meta_keys key:8;
enum nft_registers dreg:8;
};
static void nft_meta_eval(const struct nft_expr *expr,
struct nft_data data[NFT_REG_MAX + 1],
const struct nft_pktinfo *pkt)
{
const struct nft_meta *priv = nft_expr_priv(expr);
const struct sk_buff *skb = pkt->skb;
const struct net_device *in = pkt->in, *out = pkt->out;
struct nft_data *dest = &data[priv->dreg];
switch (priv->key) {
case NFT_META_LEN:
dest->data[0] = skb->len;
break;
case NFT_META_PROTOCOL:
*(__be16 *)dest->data = skb->protocol;
break;
case NFT_META_PRIORITY:
dest->data[0] = skb->priority;
break;
case NFT_META_MARK:
dest->data[0] = skb->mark;
break;
case NFT_META_IIF:
if (in == NULL)
goto err;
dest->data[0] = in->ifindex;
break;
case NFT_META_OIF:
if (out == NULL)
goto err;
dest->data[0] = out->ifindex;
break;
case NFT_META_IIFNAME:
if (in == NULL)
goto err;
strncpy((char *)dest->data, in->name, sizeof(dest->data));
break;
case NFT_META_OIFNAME:
if (out == NULL)
goto err;
strncpy((char *)dest->data, out->name, sizeof(dest->data));
break;
case NFT_META_IIFTYPE:
if (in == NULL)
goto err;
*(u16 *)dest->data = in->type;
break;
case NFT_META_OIFTYPE:
if (out == NULL)
goto err;
*(u16 *)dest->data = out->type;
break;
case NFT_META_SKUID:
if (skb->sk == NULL || skb->sk->sk_state == TCP_TIME_WAIT)
goto err;
read_lock_bh(&skb->sk->sk_callback_lock);
if (skb->sk->sk_socket == NULL ||
skb->sk->sk_socket->file == NULL) {
read_unlock_bh(&skb->sk->sk_callback_lock);
goto err;
}
dest->data[0] =
from_kuid_munged(&init_user_ns,
skb->sk->sk_socket->file->f_cred->fsuid);
read_unlock_bh(&skb->sk->sk_callback_lock);
break;
case NFT_META_SKGID:
if (skb->sk == NULL || skb->sk->sk_state == TCP_TIME_WAIT)
goto err;
read_lock_bh(&skb->sk->sk_callback_lock);
if (skb->sk->sk_socket == NULL ||
skb->sk->sk_socket->file == NULL) {
read_unlock_bh(&skb->sk->sk_callback_lock);
goto err;
}
dest->data[0] =
from_kgid_munged(&init_user_ns,
skb->sk->sk_socket->file->f_cred->fsgid);
read_unlock_bh(&skb->sk->sk_callback_lock);
break;
#ifdef CONFIG_NET_CLS_ROUTE
case NFT_META_RTCLASSID: {
const struct dst_entry *dst = skb_dst(skb);
if (dst == NULL)
goto err;
dest->data[0] = dst->tclassid;
break;
}
#endif
#ifdef CONFIG_NETWORK_SECMARK
case NFT_META_SECMARK:
dest->data[0] = skb->secmark;
break;
#endif
default:
WARN_ON(1);
goto err;
}
return;
err:
data[NFT_REG_VERDICT].verdict = NFT_BREAK;
}
static const struct nla_policy nft_meta_policy[NFTA_META_MAX + 1] = {
[NFTA_META_DREG] = { .type = NLA_U32 },
[NFTA_META_KEY] = { .type = NLA_U32 },
};
static int nft_meta_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
const struct nlattr * const tb[])
{
struct nft_meta *priv = nft_expr_priv(expr);
int err;
if (tb[NFTA_META_DREG] == NULL ||
tb[NFTA_META_KEY] == NULL)
return -EINVAL;
priv->key = ntohl(nla_get_be32(tb[NFTA_META_KEY]));
switch (priv->key) {
case NFT_META_LEN:
case NFT_META_PROTOCOL:
case NFT_META_PRIORITY:
case NFT_META_MARK:
case NFT_META_IIF:
case NFT_META_OIF:
case NFT_META_IIFNAME:
case NFT_META_OIFNAME:
case NFT_META_IIFTYPE:
case NFT_META_OIFTYPE:
case NFT_META_SKUID:
case NFT_META_SKGID:
#ifdef CONFIG_NET_CLS_ROUTE
case NFT_META_RTCLASSID:
#endif
#ifdef CONFIG_NETWORK_SECMARK
case NFT_META_SECMARK:
#endif
break;
default:
return -EOPNOTSUPP;
}
priv->dreg = ntohl(nla_get_be32(tb[NFTA_META_DREG]));
err = nft_validate_output_register(priv->dreg);
if (err < 0)
return err;
return nft_validate_data_load(ctx, priv->dreg, NULL, NFT_DATA_VALUE);
}
static int nft_meta_dump(struct sk_buff *skb, const struct nft_expr *expr)
{
const struct nft_meta *priv = nft_expr_priv(expr);
if (nla_put_be32(skb, NFTA_META_DREG, htonl(priv->dreg)))
goto nla_put_failure;
if (nla_put_be32(skb, NFTA_META_KEY, htonl(priv->key)))
goto nla_put_failure;
return 0;
nla_put_failure:
return -1;
}
static struct nft_expr_type nft_meta_type;
static const struct nft_expr_ops nft_meta_ops = {
.type = &nft_meta_type,
.size = NFT_EXPR_SIZE(sizeof(struct nft_meta)),
.eval = nft_meta_eval,
.init = nft_meta_init,
.dump = nft_meta_dump,
};
static struct nft_expr_type nft_meta_type __read_mostly = {
.name = "meta",
.ops = &nft_meta_ops,
.policy = nft_meta_policy,
.maxattr = NFTA_META_MAX,
.owner = THIS_MODULE,
};
static int __init nft_meta_module_init(void)
{
return nft_register_expr(&nft_meta_type);
}
static void __exit nft_meta_module_exit(void)
{
nft_unregister_expr(&nft_meta_type);
}
module_init(nft_meta_module_init);
module_exit(nft_meta_module_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
MODULE_ALIAS_NFT_EXPR("meta");