Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1/* Kernel module to match connection tracking byte counter.
2 * GPL (C) 2002 Martin Devera (devik@cdi.cz).
3 */
4#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
5#include <linux/module.h>
6#include <linux/bitops.h>
7#include <linux/skbuff.h>
8#include <linux/math64.h>
9#include <linux/netfilter/x_tables.h>
10#include <linux/netfilter/xt_connbytes.h>
11#include <net/netfilter/nf_conntrack.h>
12#include <net/netfilter/nf_conntrack_acct.h>
13
14MODULE_LICENSE("GPL");
15MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
16MODULE_DESCRIPTION("Xtables: Number of packets/bytes per connection matching");
17MODULE_ALIAS("ipt_connbytes");
18MODULE_ALIAS("ip6t_connbytes");
19
20static bool
21connbytes_mt(const struct sk_buff *skb, struct xt_action_param *par)
22{
23 const struct xt_connbytes_info *sinfo = par->matchinfo;
24 const struct nf_conn *ct;
25 enum ip_conntrack_info ctinfo;
26 u_int64_t what = 0; /* initialize to make gcc happy */
27 u_int64_t bytes = 0;
28 u_int64_t pkts = 0;
29 const struct nf_conn_counter *counters;
30
31 ct = nf_ct_get(skb, &ctinfo);
32 if (!ct)
33 return false;
34
35 counters = nf_conn_acct_find(ct);
36 if (!counters)
37 return false;
38
39 switch (sinfo->what) {
40 case XT_CONNBYTES_PKTS:
41 switch (sinfo->direction) {
42 case XT_CONNBYTES_DIR_ORIGINAL:
43 what = counters[IP_CT_DIR_ORIGINAL].packets;
44 break;
45 case XT_CONNBYTES_DIR_REPLY:
46 what = counters[IP_CT_DIR_REPLY].packets;
47 break;
48 case XT_CONNBYTES_DIR_BOTH:
49 what = counters[IP_CT_DIR_ORIGINAL].packets;
50 what += counters[IP_CT_DIR_REPLY].packets;
51 break;
52 }
53 break;
54 case XT_CONNBYTES_BYTES:
55 switch (sinfo->direction) {
56 case XT_CONNBYTES_DIR_ORIGINAL:
57 what = counters[IP_CT_DIR_ORIGINAL].bytes;
58 break;
59 case XT_CONNBYTES_DIR_REPLY:
60 what = counters[IP_CT_DIR_REPLY].bytes;
61 break;
62 case XT_CONNBYTES_DIR_BOTH:
63 what = counters[IP_CT_DIR_ORIGINAL].bytes;
64 what += counters[IP_CT_DIR_REPLY].bytes;
65 break;
66 }
67 break;
68 case XT_CONNBYTES_AVGPKT:
69 switch (sinfo->direction) {
70 case XT_CONNBYTES_DIR_ORIGINAL:
71 bytes = counters[IP_CT_DIR_ORIGINAL].bytes;
72 pkts = counters[IP_CT_DIR_ORIGINAL].packets;
73 break;
74 case XT_CONNBYTES_DIR_REPLY:
75 bytes = counters[IP_CT_DIR_REPLY].bytes;
76 pkts = counters[IP_CT_DIR_REPLY].packets;
77 break;
78 case XT_CONNBYTES_DIR_BOTH:
79 bytes = counters[IP_CT_DIR_ORIGINAL].bytes +
80 counters[IP_CT_DIR_REPLY].bytes;
81 pkts = counters[IP_CT_DIR_ORIGINAL].packets +
82 counters[IP_CT_DIR_REPLY].packets;
83 break;
84 }
85 if (pkts != 0)
86 what = div64_u64(bytes, pkts);
87 break;
88 }
89
90 if (sinfo->count.to >= sinfo->count.from)
91 return what <= sinfo->count.to && what >= sinfo->count.from;
92 else /* inverted */
93 return what < sinfo->count.to || what > sinfo->count.from;
94}
95
96static int connbytes_mt_check(const struct xt_mtchk_param *par)
97{
98 const struct xt_connbytes_info *sinfo = par->matchinfo;
99 int ret;
100
101 if (sinfo->what != XT_CONNBYTES_PKTS &&
102 sinfo->what != XT_CONNBYTES_BYTES &&
103 sinfo->what != XT_CONNBYTES_AVGPKT)
104 return -EINVAL;
105
106 if (sinfo->direction != XT_CONNBYTES_DIR_ORIGINAL &&
107 sinfo->direction != XT_CONNBYTES_DIR_REPLY &&
108 sinfo->direction != XT_CONNBYTES_DIR_BOTH)
109 return -EINVAL;
110
111 ret = nf_ct_l3proto_try_module_get(par->family);
112 if (ret < 0)
113 pr_info("cannot load conntrack support for proto=%u\n",
114 par->family);
115
116 /*
117 * This filter cannot function correctly unless connection tracking
118 * accounting is enabled, so complain in the hope that someone notices.
119 */
120 if (!nf_ct_acct_enabled(par->net)) {
121 pr_warning("Forcing CT accounting to be enabled\n");
122 nf_ct_set_acct(par->net, true);
123 }
124
125 return ret;
126}
127
128static void connbytes_mt_destroy(const struct xt_mtdtor_param *par)
129{
130 nf_ct_l3proto_module_put(par->family);
131}
132
133static struct xt_match connbytes_mt_reg __read_mostly = {
134 .name = "connbytes",
135 .revision = 0,
136 .family = NFPROTO_UNSPEC,
137 .checkentry = connbytes_mt_check,
138 .match = connbytes_mt,
139 .destroy = connbytes_mt_destroy,
140 .matchsize = sizeof(struct xt_connbytes_info),
141 .me = THIS_MODULE,
142};
143
144static int __init connbytes_mt_init(void)
145{
146 return xt_register_match(&connbytes_mt_reg);
147}
148
149static void __exit connbytes_mt_exit(void)
150{
151 xt_unregister_match(&connbytes_mt_reg);
152}
153
154module_init(connbytes_mt_init);
155module_exit(connbytes_mt_exit);