2 * xt_conntrack - Netfilter module to match connection tracking
3 * information. (Superset of Rusty's minimalistic state match.)
5 * (C) 2001 Marc Boucher (marc@mbsi.ca).
6 * Copyright © CC Computer Consultants GmbH, 2007 - 2008
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13 #include <linux/module.h>
14 #include <linux/skbuff.h>
16 #include <linux/netfilter/x_tables.h>
17 #include <linux/netfilter/xt_conntrack.h>
18 #include <net/netfilter/nf_conntrack.h>
20 MODULE_LICENSE("GPL");
21 MODULE_AUTHOR("Marc Boucher <marc@mbsi.ca>");
22 MODULE_AUTHOR("Jan Engelhardt <jengelh@medozas.de>");
23 MODULE_DESCRIPTION("Xtables: connection tracking state match");
24 MODULE_ALIAS("ipt_conntrack");
25 MODULE_ALIAS("ip6t_conntrack");
28 conntrack_addrcmp(const union nf_inet_addr
*kaddr
,
29 const union nf_inet_addr
*uaddr
,
30 const union nf_inet_addr
*umask
, unsigned int l3proto
)
32 if (l3proto
== NFPROTO_IPV4
)
33 return ((kaddr
->ip
^ uaddr
->ip
) & umask
->ip
) == 0;
34 else if (l3proto
== NFPROTO_IPV6
)
35 return ipv6_masked_addr_cmp(&kaddr
->in6
, &umask
->in6
,
42 conntrack_mt_origsrc(const struct nf_conn
*ct
,
43 const struct xt_conntrack_mtinfo2
*info
,
46 return conntrack_addrcmp(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].tuple
.src
.u3
,
47 &info
->origsrc_addr
, &info
->origsrc_mask
, family
);
51 conntrack_mt_origdst(const struct nf_conn
*ct
,
52 const struct xt_conntrack_mtinfo2
*info
,
55 return conntrack_addrcmp(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].tuple
.dst
.u3
,
56 &info
->origdst_addr
, &info
->origdst_mask
, family
);
60 conntrack_mt_replsrc(const struct nf_conn
*ct
,
61 const struct xt_conntrack_mtinfo2
*info
,
64 return conntrack_addrcmp(&ct
->tuplehash
[IP_CT_DIR_REPLY
].tuple
.src
.u3
,
65 &info
->replsrc_addr
, &info
->replsrc_mask
, family
);
69 conntrack_mt_repldst(const struct nf_conn
*ct
,
70 const struct xt_conntrack_mtinfo2
*info
,
73 return conntrack_addrcmp(&ct
->tuplehash
[IP_CT_DIR_REPLY
].tuple
.dst
.u3
,
74 &info
->repldst_addr
, &info
->repldst_mask
, family
);
78 ct_proto_port_check(const struct xt_conntrack_mtinfo2
*info
,
79 const struct nf_conn
*ct
)
81 const struct nf_conntrack_tuple
*tuple
;
83 tuple
= &ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].tuple
;
84 if ((info
->match_flags
& XT_CONNTRACK_PROTO
) &&
85 (nf_ct_protonum(ct
) == info
->l4proto
) ^
86 !(info
->invert_flags
& XT_CONNTRACK_PROTO
))
89 /* Shortcut to match all recognized protocols by using ->src.all. */
90 if ((info
->match_flags
& XT_CONNTRACK_ORIGSRC_PORT
) &&
91 (tuple
->src
.u
.all
== info
->origsrc_port
) ^
92 !(info
->invert_flags
& XT_CONNTRACK_ORIGSRC_PORT
))
95 if ((info
->match_flags
& XT_CONNTRACK_ORIGDST_PORT
) &&
96 (tuple
->dst
.u
.all
== info
->origdst_port
) ^
97 !(info
->invert_flags
& XT_CONNTRACK_ORIGDST_PORT
))
100 tuple
= &ct
->tuplehash
[IP_CT_DIR_REPLY
].tuple
;
102 if ((info
->match_flags
& XT_CONNTRACK_REPLSRC_PORT
) &&
103 (tuple
->src
.u
.all
== info
->replsrc_port
) ^
104 !(info
->invert_flags
& XT_CONNTRACK_REPLSRC_PORT
))
107 if ((info
->match_flags
& XT_CONNTRACK_REPLDST_PORT
) &&
108 (tuple
->dst
.u
.all
== info
->repldst_port
) ^
109 !(info
->invert_flags
& XT_CONNTRACK_REPLDST_PORT
))
116 port_match(u16 min
, u16 max
, u16 port
, bool invert
)
118 return (port
>= min
&& port
<= max
) ^ invert
;
122 ct_proto_port_check_v3(const struct xt_conntrack_mtinfo3
*info
,
123 const struct nf_conn
*ct
)
125 const struct nf_conntrack_tuple
*tuple
;
127 tuple
= &ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].tuple
;
128 if ((info
->match_flags
& XT_CONNTRACK_PROTO
) &&
129 (nf_ct_protonum(ct
) == info
->l4proto
) ^
130 !(info
->invert_flags
& XT_CONNTRACK_PROTO
))
133 /* Shortcut to match all recognized protocols by using ->src.all. */
134 if ((info
->match_flags
& XT_CONNTRACK_ORIGSRC_PORT
) &&
135 !port_match(info
->origsrc_port
, info
->origsrc_port_high
,
136 ntohs(tuple
->src
.u
.all
),
137 info
->invert_flags
& XT_CONNTRACK_ORIGSRC_PORT
))
140 if ((info
->match_flags
& XT_CONNTRACK_ORIGDST_PORT
) &&
141 !port_match(info
->origdst_port
, info
->origdst_port_high
,
142 ntohs(tuple
->dst
.u
.all
),
143 info
->invert_flags
& XT_CONNTRACK_ORIGDST_PORT
))
146 tuple
= &ct
->tuplehash
[IP_CT_DIR_REPLY
].tuple
;
148 if ((info
->match_flags
& XT_CONNTRACK_REPLSRC_PORT
) &&
149 !port_match(info
->replsrc_port
, info
->replsrc_port_high
,
150 ntohs(tuple
->src
.u
.all
),
151 info
->invert_flags
& XT_CONNTRACK_REPLSRC_PORT
))
154 if ((info
->match_flags
& XT_CONNTRACK_REPLDST_PORT
) &&
155 !port_match(info
->repldst_port
, info
->repldst_port_high
,
156 ntohs(tuple
->dst
.u
.all
),
157 info
->invert_flags
& XT_CONNTRACK_REPLDST_PORT
))
164 conntrack_mt(const struct sk_buff
*skb
, struct xt_action_param
*par
,
165 u16 state_mask
, u16 status_mask
)
167 const struct xt_conntrack_mtinfo2
*info
= par
->matchinfo
;
168 enum ip_conntrack_info ctinfo
;
169 const struct nf_conn
*ct
;
170 unsigned int statebit
;
172 ct
= nf_ct_get(skb
, &ctinfo
);
175 if (nf_ct_is_untracked(ct
))
176 statebit
= XT_CONNTRACK_STATE_UNTRACKED
;
178 statebit
= XT_CONNTRACK_STATE_BIT(ctinfo
);
180 statebit
= XT_CONNTRACK_STATE_INVALID
;
182 if (info
->match_flags
& XT_CONNTRACK_STATE
) {
184 if (test_bit(IPS_SRC_NAT_BIT
, &ct
->status
))
185 statebit
|= XT_CONNTRACK_STATE_SNAT
;
186 if (test_bit(IPS_DST_NAT_BIT
, &ct
->status
))
187 statebit
|= XT_CONNTRACK_STATE_DNAT
;
189 if (!!(state_mask
& statebit
) ^
190 !(info
->invert_flags
& XT_CONNTRACK_STATE
))
195 return info
->match_flags
& XT_CONNTRACK_STATE
;
196 if ((info
->match_flags
& XT_CONNTRACK_DIRECTION
) &&
197 (CTINFO2DIR(ctinfo
) == IP_CT_DIR_ORIGINAL
) ^
198 !!(info
->invert_flags
& XT_CONNTRACK_DIRECTION
))
201 if (info
->match_flags
& XT_CONNTRACK_ORIGSRC
)
202 if (conntrack_mt_origsrc(ct
, info
, par
->family
) ^
203 !(info
->invert_flags
& XT_CONNTRACK_ORIGSRC
))
206 if (info
->match_flags
& XT_CONNTRACK_ORIGDST
)
207 if (conntrack_mt_origdst(ct
, info
, par
->family
) ^
208 !(info
->invert_flags
& XT_CONNTRACK_ORIGDST
))
211 if (info
->match_flags
& XT_CONNTRACK_REPLSRC
)
212 if (conntrack_mt_replsrc(ct
, info
, par
->family
) ^
213 !(info
->invert_flags
& XT_CONNTRACK_REPLSRC
))
216 if (info
->match_flags
& XT_CONNTRACK_REPLDST
)
217 if (conntrack_mt_repldst(ct
, info
, par
->family
) ^
218 !(info
->invert_flags
& XT_CONNTRACK_REPLDST
))
221 if (par
->match
->revision
!= 3) {
222 if (!ct_proto_port_check(info
, ct
))
225 if (!ct_proto_port_check_v3(par
->matchinfo
, ct
))
229 if ((info
->match_flags
& XT_CONNTRACK_STATUS
) &&
230 (!!(status_mask
& ct
->status
) ^
231 !(info
->invert_flags
& XT_CONNTRACK_STATUS
)))
234 if (info
->match_flags
& XT_CONNTRACK_EXPIRES
) {
235 unsigned long expires
= 0;
237 if (timer_pending(&ct
->timeout
))
238 expires
= (ct
->timeout
.expires
- jiffies
) / HZ
;
239 if ((expires
>= info
->expires_min
&&
240 expires
<= info
->expires_max
) ^
241 !(info
->invert_flags
& XT_CONNTRACK_EXPIRES
))
248 conntrack_mt_v1(const struct sk_buff
*skb
, struct xt_action_param
*par
)
250 const struct xt_conntrack_mtinfo1
*info
= par
->matchinfo
;
252 return conntrack_mt(skb
, par
, info
->state_mask
, info
->status_mask
);
256 conntrack_mt_v2(const struct sk_buff
*skb
, struct xt_action_param
*par
)
258 const struct xt_conntrack_mtinfo2
*info
= par
->matchinfo
;
260 return conntrack_mt(skb
, par
, info
->state_mask
, info
->status_mask
);
264 conntrack_mt_v3(const struct sk_buff
*skb
, struct xt_action_param
*par
)
266 const struct xt_conntrack_mtinfo3
*info
= par
->matchinfo
;
268 return conntrack_mt(skb
, par
, info
->state_mask
, info
->status_mask
);
271 static int conntrack_mt_check(const struct xt_mtchk_param
*par
)
275 if (strcmp(par
->table
, "raw") == 0) {
276 pr_info("state is undetermined at the time of raw table\n");
280 ret
= nf_ct_l3proto_try_module_get(par
->family
);
282 pr_info("cannot load conntrack support for proto=%u\n",
287 static void conntrack_mt_destroy(const struct xt_mtdtor_param
*par
)
289 nf_ct_l3proto_module_put(par
->family
);
292 static struct xt_match conntrack_mt_reg
[] __read_mostly
= {
296 .family
= NFPROTO_UNSPEC
,
297 .matchsize
= sizeof(struct xt_conntrack_mtinfo1
),
298 .match
= conntrack_mt_v1
,
299 .checkentry
= conntrack_mt_check
,
300 .destroy
= conntrack_mt_destroy
,
306 .family
= NFPROTO_UNSPEC
,
307 .matchsize
= sizeof(struct xt_conntrack_mtinfo2
),
308 .match
= conntrack_mt_v2
,
309 .checkentry
= conntrack_mt_check
,
310 .destroy
= conntrack_mt_destroy
,
316 .family
= NFPROTO_UNSPEC
,
317 .matchsize
= sizeof(struct xt_conntrack_mtinfo3
),
318 .match
= conntrack_mt_v3
,
319 .checkentry
= conntrack_mt_check
,
320 .destroy
= conntrack_mt_destroy
,
325 static int __init
conntrack_mt_init(void)
327 return xt_register_matches(conntrack_mt_reg
,
328 ARRAY_SIZE(conntrack_mt_reg
));
331 static void __exit
conntrack_mt_exit(void)
333 xt_unregister_matches(conntrack_mt_reg
, ARRAY_SIZE(conntrack_mt_reg
));
336 module_init(conntrack_mt_init
);
337 module_exit(conntrack_mt_exit
);