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
|
/* Kernel module to match connection tracking byte counter.
* GPL (C) 2002 Martin Devera (devik@cdi.cz).
*/
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/netfilter/x_tables.h>
#include <linux/netfilter/xt_connbytes.h>
#include <net/netfilter/nf_conntrack.h>
#include <asm/div64.h>
#include <asm/bitops.h>
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
MODULE_DESCRIPTION("iptables match for matching number of pkts/bytes per connection");
MODULE_ALIAS("ipt_connbytes");
static bool
match(const struct sk_buff *skb,
const struct net_device *in,
const struct net_device *out,
const struct xt_match *match,
const void *matchinfo,
int offset,
unsigned int protoff,
bool *hotdrop)
{
const struct xt_connbytes_info *sinfo = matchinfo;
const struct nf_conn *ct;
enum ip_conntrack_info ctinfo;
u_int64_t what = 0; /* initialize to make gcc happy */
u_int64_t bytes = 0;
u_int64_t pkts = 0;
const struct ip_conntrack_counter *counters;
ct = nf_ct_get(skb, &ctinfo);
if (!ct)
return false;
counters = ct->counters;
switch (sinfo->what) {
case XT_CONNBYTES_PKTS:
switch (sinfo->direction) {
case XT_CONNBYTES_DIR_ORIGINAL:
what = counters[IP_CT_DIR_ORIGINAL].packets;
break;
case XT_CONNBYTES_DIR_REPLY:
what = counters[IP_CT_DIR_REPLY].packets;
break;
case XT_CONNBYTES_DIR_BOTH:
what = counters[IP_CT_DIR_ORIGINAL].packets;
what += counters[IP_CT_DIR_REPLY].packets;
break;
}
break;
case XT_CONNBYTES_BYTES:
switch (sinfo->direction) {
case XT_CONNBYTES_DIR_ORIGINAL:
what = counters[IP_CT_DIR_ORIGINAL].bytes;
break;
case XT_CONNBYTES_DIR_REPLY:
what = counters[IP_CT_DIR_REPLY].bytes;
break;
case XT_CONNBYTES_DIR_BOTH:
what = counters[IP_CT_DIR_ORIGINAL].bytes;
what += counters[IP_CT_DIR_REPLY].bytes;
break;
}
break;
case XT_CONNBYTES_AVGPKT:
switch (sinfo->direction) {
case XT_CONNBYTES_DIR_ORIGINAL:
bytes = counters[IP_CT_DIR_ORIGINAL].bytes;
pkts = counters[IP_CT_DIR_ORIGINAL].packets;
break;
case XT_CONNBYTES_DIR_REPLY:
bytes = counters[IP_CT_DIR_REPLY].bytes;
pkts = counters[IP_CT_DIR_REPLY].packets;
break;
case XT_CONNBYTES_DIR_BOTH:
bytes = counters[IP_CT_DIR_ORIGINAL].bytes +
counters[IP_CT_DIR_REPLY].bytes;
pkts = counters[IP_CT_DIR_ORIGINAL].packets +
counters[IP_CT_DIR_REPLY].packets;
break;
}
if (pkts != 0)
what = div64_64(bytes, pkts);
break;
}
if (sinfo->count.to)
return what <= sinfo->count.to && what >= sinfo->count.from;
else
return what >= sinfo->count.from;
}
static bool check(const char *tablename,
const void *ip,
const struct xt_match *match,
void *matchinfo,
unsigned int hook_mask)
{
const struct xt_connbytes_info *sinfo = matchinfo;
if (sinfo->what != XT_CONNBYTES_PKTS &&
sinfo->what != XT_CONNBYTES_BYTES &&
sinfo->what != XT_CONNBYTES_AVGPKT)
return false;
if (sinfo->direction != XT_CONNBYTES_DIR_ORIGINAL &&
sinfo->direction != XT_CONNBYTES_DIR_REPLY &&
sinfo->direction != XT_CONNBYTES_DIR_BOTH)
return false;
if (nf_ct_l3proto_try_module_get(match->family) < 0) {
printk(KERN_WARNING "can't load conntrack support for "
"proto=%d\n", match->family);
return false;
}
return true;
}
static void
destroy(const struct xt_match *match, void *matchinfo)
{
nf_ct_l3proto_module_put(match->family);
}
static struct xt_match xt_connbytes_match[] = {
{
.name = "connbytes",
.family = AF_INET,
.checkentry = check,
.match = match,
.destroy = destroy,
.matchsize = sizeof(struct xt_connbytes_info),
.me = THIS_MODULE
},
{
.name = "connbytes",
.family = AF_INET6,
.checkentry = check,
.match = match,
.destroy = destroy,
.matchsize = sizeof(struct xt_connbytes_info),
.me = THIS_MODULE
},
};
static int __init xt_connbytes_init(void)
{
return xt_register_matches(xt_connbytes_match,
ARRAY_SIZE(xt_connbytes_match));
}
static void __exit xt_connbytes_fini(void)
{
xt_unregister_matches(xt_connbytes_match,
ARRAY_SIZE(xt_connbytes_match));
}
module_init(xt_connbytes_init);
module_exit(xt_connbytes_fini);
|
