netfilter: nf_conntrack: use per-conntrack locks for protocol data
[linux-2.6.git] / net / netfilter / xt_conntrack.c
1 /*
2  *      xt_conntrack - Netfilter module to match connection tracking
3  *      information. (Superset of Rusty's minimalistic state match.)
4  *
5  *      (C) 2001  Marc Boucher (marc@mbsi.ca).
6  *      Copyright © CC Computer Consultants GmbH, 2007 - 2008
7  *
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.
11  */
12
13 #include <linux/module.h>
14 #include <linux/skbuff.h>
15 #include <net/ipv6.h>
16 #include <linux/netfilter/x_tables.h>
17 #include <linux/netfilter/xt_conntrack.h>
18 #include <net/netfilter/nf_conntrack.h>
19
20 MODULE_LICENSE("GPL");
21 MODULE_AUTHOR("Marc Boucher <marc@mbsi.ca>");
22 MODULE_AUTHOR("Jan Engelhardt <jengelh@computergmbh.de>");
23 MODULE_DESCRIPTION("Xtables: connection tracking state match");
24 MODULE_ALIAS("ipt_conntrack");
25 MODULE_ALIAS("ip6t_conntrack");
26
27 static bool
28 conntrack_mt_v0(const struct sk_buff *skb, const struct xt_match_param *par)
29 {
30         const struct xt_conntrack_info *sinfo = par->matchinfo;
31         const struct nf_conn *ct;
32         enum ip_conntrack_info ctinfo;
33         unsigned int statebit;
34
35         ct = nf_ct_get(skb, &ctinfo);
36
37 #define FWINV(bool, invflg) ((bool) ^ !!(sinfo->invflags & (invflg)))
38
39         if (ct == &nf_conntrack_untracked)
40                 statebit = XT_CONNTRACK_STATE_UNTRACKED;
41         else if (ct)
42                 statebit = XT_CONNTRACK_STATE_BIT(ctinfo);
43         else
44                 statebit = XT_CONNTRACK_STATE_INVALID;
45
46         if (sinfo->flags & XT_CONNTRACK_STATE) {
47                 if (ct) {
48                         if (test_bit(IPS_SRC_NAT_BIT, &ct->status))
49                                 statebit |= XT_CONNTRACK_STATE_SNAT;
50                         if (test_bit(IPS_DST_NAT_BIT, &ct->status))
51                                 statebit |= XT_CONNTRACK_STATE_DNAT;
52                 }
53                 if (FWINV((statebit & sinfo->statemask) == 0,
54                           XT_CONNTRACK_STATE))
55                         return false;
56         }
57
58         if (ct == NULL) {
59                 if (sinfo->flags & ~XT_CONNTRACK_STATE)
60                         return false;
61                 return true;
62         }
63
64         if (sinfo->flags & XT_CONNTRACK_PROTO &&
65             FWINV(nf_ct_protonum(ct) !=
66                   sinfo->tuple[IP_CT_DIR_ORIGINAL].dst.protonum,
67                   XT_CONNTRACK_PROTO))
68                 return false;
69
70         if (sinfo->flags & XT_CONNTRACK_ORIGSRC &&
71             FWINV((ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3.ip &
72                    sinfo->sipmsk[IP_CT_DIR_ORIGINAL].s_addr) !=
73                   sinfo->tuple[IP_CT_DIR_ORIGINAL].src.ip,
74                   XT_CONNTRACK_ORIGSRC))
75                 return false;
76
77         if (sinfo->flags & XT_CONNTRACK_ORIGDST &&
78             FWINV((ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.u3.ip &
79                    sinfo->dipmsk[IP_CT_DIR_ORIGINAL].s_addr) !=
80                   sinfo->tuple[IP_CT_DIR_ORIGINAL].dst.ip,
81                   XT_CONNTRACK_ORIGDST))
82                 return false;
83
84         if (sinfo->flags & XT_CONNTRACK_REPLSRC &&
85             FWINV((ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.u3.ip &
86                    sinfo->sipmsk[IP_CT_DIR_REPLY].s_addr) !=
87                   sinfo->tuple[IP_CT_DIR_REPLY].src.ip,
88                   XT_CONNTRACK_REPLSRC))
89                 return false;
90
91         if (sinfo->flags & XT_CONNTRACK_REPLDST &&
92             FWINV((ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.u3.ip &
93                    sinfo->dipmsk[IP_CT_DIR_REPLY].s_addr) !=
94                   sinfo->tuple[IP_CT_DIR_REPLY].dst.ip,
95                   XT_CONNTRACK_REPLDST))
96                 return false;
97
98         if (sinfo->flags & XT_CONNTRACK_STATUS &&
99             FWINV((ct->status & sinfo->statusmask) == 0,
100                   XT_CONNTRACK_STATUS))
101                 return false;
102
103         if(sinfo->flags & XT_CONNTRACK_EXPIRES) {
104                 unsigned long expires = timer_pending(&ct->timeout) ?
105                                         (ct->timeout.expires - jiffies)/HZ : 0;
106
107                 if (FWINV(!(expires >= sinfo->expires_min &&
108                             expires <= sinfo->expires_max),
109                           XT_CONNTRACK_EXPIRES))
110                         return false;
111         }
112         return true;
113 #undef FWINV
114 }
115
116 static bool
117 conntrack_addrcmp(const union nf_inet_addr *kaddr,
118                   const union nf_inet_addr *uaddr,
119                   const union nf_inet_addr *umask, unsigned int l3proto)
120 {
121         if (l3proto == NFPROTO_IPV4)
122                 return ((kaddr->ip ^ uaddr->ip) & umask->ip) == 0;
123         else if (l3proto == NFPROTO_IPV6)
124                 return ipv6_masked_addr_cmp(&kaddr->in6, &umask->in6,
125                        &uaddr->in6) == 0;
126         else
127                 return false;
128 }
129
130 static inline bool
131 conntrack_mt_origsrc(const struct nf_conn *ct,
132                      const struct xt_conntrack_mtinfo1 *info,
133                      u_int8_t family)
134 {
135         return conntrack_addrcmp(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3,
136                &info->origsrc_addr, &info->origsrc_mask, family);
137 }
138
139 static inline bool
140 conntrack_mt_origdst(const struct nf_conn *ct,
141                      const struct xt_conntrack_mtinfo1 *info,
142                      u_int8_t family)
143 {
144         return conntrack_addrcmp(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.u3,
145                &info->origdst_addr, &info->origdst_mask, family);
146 }
147
148 static inline bool
149 conntrack_mt_replsrc(const struct nf_conn *ct,
150                      const struct xt_conntrack_mtinfo1 *info,
151                      u_int8_t family)
152 {
153         return conntrack_addrcmp(&ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.u3,
154                &info->replsrc_addr, &info->replsrc_mask, family);
155 }
156
157 static inline bool
158 conntrack_mt_repldst(const struct nf_conn *ct,
159                      const struct xt_conntrack_mtinfo1 *info,
160                      u_int8_t family)
161 {
162         return conntrack_addrcmp(&ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.u3,
163                &info->repldst_addr, &info->repldst_mask, family);
164 }
165
166 static inline bool
167 ct_proto_port_check(const struct xt_conntrack_mtinfo1 *info,
168                     const struct nf_conn *ct)
169 {
170         const struct nf_conntrack_tuple *tuple;
171
172         tuple = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple;
173         if ((info->match_flags & XT_CONNTRACK_PROTO) &&
174             (nf_ct_protonum(ct) == info->l4proto) ^
175             !(info->invert_flags & XT_CONNTRACK_PROTO))
176                 return false;
177
178         /* Shortcut to match all recognized protocols by using ->src.all. */
179         if ((info->match_flags & XT_CONNTRACK_ORIGSRC_PORT) &&
180             (tuple->src.u.all == info->origsrc_port) ^
181             !(info->invert_flags & XT_CONNTRACK_ORIGSRC_PORT))
182                 return false;
183
184         if ((info->match_flags & XT_CONNTRACK_ORIGDST_PORT) &&
185             (tuple->dst.u.all == info->origdst_port) ^
186             !(info->invert_flags & XT_CONNTRACK_ORIGDST_PORT))
187                 return false;
188
189         tuple = &ct->tuplehash[IP_CT_DIR_REPLY].tuple;
190
191         if ((info->match_flags & XT_CONNTRACK_REPLSRC_PORT) &&
192             (tuple->src.u.all == info->replsrc_port) ^
193             !(info->invert_flags & XT_CONNTRACK_REPLSRC_PORT))
194                 return false;
195
196         if ((info->match_flags & XT_CONNTRACK_REPLDST_PORT) &&
197             (tuple->dst.u.all == info->repldst_port) ^
198             !(info->invert_flags & XT_CONNTRACK_REPLDST_PORT))
199                 return false;
200
201         return true;
202 }
203
204 static bool
205 conntrack_mt(const struct sk_buff *skb, const struct xt_match_param *par)
206 {
207         const struct xt_conntrack_mtinfo1 *info = par->matchinfo;
208         enum ip_conntrack_info ctinfo;
209         const struct nf_conn *ct;
210         unsigned int statebit;
211
212         ct = nf_ct_get(skb, &ctinfo);
213
214         if (ct == &nf_conntrack_untracked)
215                 statebit = XT_CONNTRACK_STATE_UNTRACKED;
216         else if (ct != NULL)
217                 statebit = XT_CONNTRACK_STATE_BIT(ctinfo);
218         else
219                 statebit = XT_CONNTRACK_STATE_INVALID;
220
221         if (info->match_flags & XT_CONNTRACK_STATE) {
222                 if (ct != NULL) {
223                         if (test_bit(IPS_SRC_NAT_BIT, &ct->status))
224                                 statebit |= XT_CONNTRACK_STATE_SNAT;
225                         if (test_bit(IPS_DST_NAT_BIT, &ct->status))
226                                 statebit |= XT_CONNTRACK_STATE_DNAT;
227                 }
228                 if (!!(info->state_mask & statebit) ^
229                     !(info->invert_flags & XT_CONNTRACK_STATE))
230                         return false;
231         }
232
233         if (ct == NULL)
234                 return info->match_flags & XT_CONNTRACK_STATE;
235         if ((info->match_flags & XT_CONNTRACK_DIRECTION) &&
236             (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL) ^
237             !!(info->invert_flags & XT_CONNTRACK_DIRECTION))
238                 return false;
239
240         if (info->match_flags & XT_CONNTRACK_ORIGSRC)
241                 if (conntrack_mt_origsrc(ct, info, par->family) ^
242                     !(info->invert_flags & XT_CONNTRACK_ORIGSRC))
243                         return false;
244
245         if (info->match_flags & XT_CONNTRACK_ORIGDST)
246                 if (conntrack_mt_origdst(ct, info, par->family) ^
247                     !(info->invert_flags & XT_CONNTRACK_ORIGDST))
248                         return false;
249
250         if (info->match_flags & XT_CONNTRACK_REPLSRC)
251                 if (conntrack_mt_replsrc(ct, info, par->family) ^
252                     !(info->invert_flags & XT_CONNTRACK_REPLSRC))
253                         return false;
254
255         if (info->match_flags & XT_CONNTRACK_REPLDST)
256                 if (conntrack_mt_repldst(ct, info, par->family) ^
257                     !(info->invert_flags & XT_CONNTRACK_REPLDST))
258                         return false;
259
260         if (!ct_proto_port_check(info, ct))
261                 return false;
262
263         if ((info->match_flags & XT_CONNTRACK_STATUS) &&
264             (!!(info->status_mask & ct->status) ^
265             !(info->invert_flags & XT_CONNTRACK_STATUS)))
266                 return false;
267
268         if (info->match_flags & XT_CONNTRACK_EXPIRES) {
269                 unsigned long expires = 0;
270
271                 if (timer_pending(&ct->timeout))
272                         expires = (ct->timeout.expires - jiffies) / HZ;
273                 if ((expires >= info->expires_min &&
274                     expires <= info->expires_max) ^
275                     !(info->invert_flags & XT_CONNTRACK_EXPIRES))
276                         return false;
277         }
278         return true;
279 }
280
281 static bool conntrack_mt_check(const struct xt_mtchk_param *par)
282 {
283         if (nf_ct_l3proto_try_module_get(par->family) < 0) {
284                 printk(KERN_WARNING "can't load conntrack support for "
285                                     "proto=%u\n", par->family);
286                 return false;
287         }
288         return true;
289 }
290
291 static void conntrack_mt_destroy(const struct xt_mtdtor_param *par)
292 {
293         nf_ct_l3proto_module_put(par->family);
294 }
295
296 #ifdef CONFIG_COMPAT
297 struct compat_xt_conntrack_info
298 {
299         compat_uint_t                   statemask;
300         compat_uint_t                   statusmask;
301         struct ip_conntrack_old_tuple   tuple[IP_CT_DIR_MAX];
302         struct in_addr                  sipmsk[IP_CT_DIR_MAX];
303         struct in_addr                  dipmsk[IP_CT_DIR_MAX];
304         compat_ulong_t                  expires_min;
305         compat_ulong_t                  expires_max;
306         u_int8_t                        flags;
307         u_int8_t                        invflags;
308 };
309
310 static void conntrack_mt_compat_from_user_v0(void *dst, void *src)
311 {
312         const struct compat_xt_conntrack_info *cm = src;
313         struct xt_conntrack_info m = {
314                 .statemask      = cm->statemask,
315                 .statusmask     = cm->statusmask,
316                 .expires_min    = cm->expires_min,
317                 .expires_max    = cm->expires_max,
318                 .flags          = cm->flags,
319                 .invflags       = cm->invflags,
320         };
321         memcpy(m.tuple, cm->tuple, sizeof(m.tuple));
322         memcpy(m.sipmsk, cm->sipmsk, sizeof(m.sipmsk));
323         memcpy(m.dipmsk, cm->dipmsk, sizeof(m.dipmsk));
324         memcpy(dst, &m, sizeof(m));
325 }
326
327 static int conntrack_mt_compat_to_user_v0(void __user *dst, void *src)
328 {
329         const struct xt_conntrack_info *m = src;
330         struct compat_xt_conntrack_info cm = {
331                 .statemask      = m->statemask,
332                 .statusmask     = m->statusmask,
333                 .expires_min    = m->expires_min,
334                 .expires_max    = m->expires_max,
335                 .flags          = m->flags,
336                 .invflags       = m->invflags,
337         };
338         memcpy(cm.tuple, m->tuple, sizeof(cm.tuple));
339         memcpy(cm.sipmsk, m->sipmsk, sizeof(cm.sipmsk));
340         memcpy(cm.dipmsk, m->dipmsk, sizeof(cm.dipmsk));
341         return copy_to_user(dst, &cm, sizeof(cm)) ? -EFAULT : 0;
342 }
343 #endif
344
345 static struct xt_match conntrack_mt_reg[] __read_mostly = {
346         {
347                 .name       = "conntrack",
348                 .revision   = 0,
349                 .family     = NFPROTO_IPV4,
350                 .match      = conntrack_mt_v0,
351                 .checkentry = conntrack_mt_check,
352                 .destroy    = conntrack_mt_destroy,
353                 .matchsize  = sizeof(struct xt_conntrack_info),
354                 .me         = THIS_MODULE,
355 #ifdef CONFIG_COMPAT
356                 .compatsize       = sizeof(struct compat_xt_conntrack_info),
357                 .compat_from_user = conntrack_mt_compat_from_user_v0,
358                 .compat_to_user   = conntrack_mt_compat_to_user_v0,
359 #endif
360         },
361         {
362                 .name       = "conntrack",
363                 .revision   = 1,
364                 .family     = NFPROTO_UNSPEC,
365                 .matchsize  = sizeof(struct xt_conntrack_mtinfo1),
366                 .match      = conntrack_mt,
367                 .checkentry = conntrack_mt_check,
368                 .destroy    = conntrack_mt_destroy,
369                 .me         = THIS_MODULE,
370         },
371 };
372
373 static int __init conntrack_mt_init(void)
374 {
375         return xt_register_matches(conntrack_mt_reg,
376                ARRAY_SIZE(conntrack_mt_reg));
377 }
378
379 static void __exit conntrack_mt_exit(void)
380 {
381         xt_unregister_matches(conntrack_mt_reg, ARRAY_SIZE(conntrack_mt_reg));
382 }
383
384 module_init(conntrack_mt_init);
385 module_exit(conntrack_mt_exit);