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