[IPV6]: Repair IPv6 Fragments
[linux-2.6] / net / sched / act_ipt.c
1 /*
2  * net/sched/ipt.c      iptables target interface
3  *
4  *TODO: Add other tables. For now we only support the ipv4 table targets
5  *
6  *              This program is free software; you can redistribute it and/or
7  *              modify it under the terms of the GNU General Public License
8  *              as published by the Free Software Foundation; either version
9  *              2 of the License, or (at your option) any later version.
10  *
11  * Copyright:   Jamal Hadi Salim (2002-4)
12  */
13
14 #include <asm/uaccess.h>
15 #include <asm/system.h>
16 #include <asm/bitops.h>
17 #include <linux/types.h>
18 #include <linux/kernel.h>
19 #include <linux/sched.h>
20 #include <linux/string.h>
21 #include <linux/mm.h>
22 #include <linux/socket.h>
23 #include <linux/sockios.h>
24 #include <linux/in.h>
25 #include <linux/errno.h>
26 #include <linux/interrupt.h>
27 #include <linux/netdevice.h>
28 #include <linux/skbuff.h>
29 #include <linux/rtnetlink.h>
30 #include <linux/module.h>
31 #include <linux/init.h>
32 #include <linux/proc_fs.h>
33 #include <linux/kmod.h>
34 #include <net/sock.h>
35 #include <net/pkt_sched.h>
36 #include <linux/tc_act/tc_ipt.h>
37 #include <net/tc_act/tc_ipt.h>
38
39 #include <linux/netfilter_ipv4/ip_tables.h>
40
41
42 #define IPT_TAB_MASK     15
43 static struct tcf_common *tcf_ipt_ht[IPT_TAB_MASK + 1];
44 static u32 ipt_idx_gen;
45 static DEFINE_RWLOCK(ipt_lock);
46
47 static struct tcf_hashinfo ipt_hash_info = {
48         .htab   =       tcf_ipt_ht,
49         .hmask  =       IPT_TAB_MASK,
50         .lock   =       &ipt_lock,
51 };
52
53 static int ipt_init_target(struct ipt_entry_target *t, char *table, unsigned int hook)
54 {
55         struct ipt_target *target;
56         int ret = 0;
57
58         target = xt_find_target(AF_INET, t->u.user.name, t->u.user.revision);
59         if (!target)
60                 return -ENOENT;
61
62         t->u.kernel.target = target;
63
64         ret = xt_check_target(target, AF_INET, t->u.target_size - sizeof(*t),
65                               table, hook, 0, 0);
66         if (ret)
67                 return ret;
68
69         if (t->u.kernel.target->checkentry
70             && !t->u.kernel.target->checkentry(table, NULL,
71                                                t->u.kernel.target, t->data,
72                                                hook)) {
73                 module_put(t->u.kernel.target->me);
74                 ret = -EINVAL;
75         }
76
77         return ret;
78 }
79
80 static void ipt_destroy_target(struct ipt_entry_target *t)
81 {
82         if (t->u.kernel.target->destroy)
83                 t->u.kernel.target->destroy(t->u.kernel.target, t->data);
84         module_put(t->u.kernel.target->me);
85 }
86
87 static int tcf_ipt_release(struct tcf_ipt *ipt, int bind)
88 {
89         int ret = 0;
90         if (ipt) {
91                 if (bind)
92                         ipt->tcf_bindcnt--;
93                 ipt->tcf_refcnt--;
94                 if (ipt->tcf_bindcnt <= 0 && ipt->tcf_refcnt <= 0) {
95                         ipt_destroy_target(ipt->tcfi_t);
96                         kfree(ipt->tcfi_tname);
97                         kfree(ipt->tcfi_t);
98                         tcf_hash_destroy(&ipt->common, &ipt_hash_info);
99                         ret = ACT_P_DELETED;
100                 }
101         }
102         return ret;
103 }
104
105 static int tcf_ipt_init(struct rtattr *rta, struct rtattr *est,
106                         struct tc_action *a, int ovr, int bind)
107 {
108         struct rtattr *tb[TCA_IPT_MAX];
109         struct tcf_ipt *ipt;
110         struct tcf_common *pc;
111         struct ipt_entry_target *td, *t;
112         char *tname;
113         int ret = 0, err;
114         u32 hook = 0;
115         u32 index = 0;
116
117         if (rta == NULL || rtattr_parse_nested(tb, TCA_IPT_MAX, rta) < 0)
118                 return -EINVAL;
119
120         if (tb[TCA_IPT_HOOK-1] == NULL ||
121             RTA_PAYLOAD(tb[TCA_IPT_HOOK-1]) < sizeof(u32))
122                 return -EINVAL;
123         if (tb[TCA_IPT_TARG-1] == NULL ||
124             RTA_PAYLOAD(tb[TCA_IPT_TARG-1]) < sizeof(*t))
125                 return -EINVAL;
126         td = (struct ipt_entry_target *)RTA_DATA(tb[TCA_IPT_TARG-1]);
127         if (RTA_PAYLOAD(tb[TCA_IPT_TARG-1]) < td->u.target_size)
128                 return -EINVAL;
129
130         if (tb[TCA_IPT_INDEX-1] != NULL &&
131             RTA_PAYLOAD(tb[TCA_IPT_INDEX-1]) >= sizeof(u32))
132                 index = *(u32 *)RTA_DATA(tb[TCA_IPT_INDEX-1]);
133
134         pc = tcf_hash_check(index, a, bind, &ipt_hash_info);
135         if (!pc) {
136                 pc = tcf_hash_create(index, est, a, sizeof(*ipt), bind,
137                                      &ipt_idx_gen, &ipt_hash_info);
138                 if (unlikely(!pc))
139                         return -ENOMEM;
140                 ret = ACT_P_CREATED;
141         } else {
142                 if (!ovr) {
143                         tcf_ipt_release(to_ipt(pc), bind);
144                         return -EEXIST;
145                 }
146         }
147         ipt = to_ipt(pc);
148
149         hook = *(u32 *)RTA_DATA(tb[TCA_IPT_HOOK-1]);
150
151         err = -ENOMEM;
152         tname = kmalloc(IFNAMSIZ, GFP_KERNEL);
153         if (unlikely(!tname))
154                 goto err1;
155         if (tb[TCA_IPT_TABLE - 1] == NULL ||
156             rtattr_strlcpy(tname, tb[TCA_IPT_TABLE-1], IFNAMSIZ) >= IFNAMSIZ)
157                 strcpy(tname, "mangle");
158
159         t = kmemdup(td, td->u.target_size, GFP_KERNEL);
160         if (unlikely(!t))
161                 goto err2;
162
163         if ((err = ipt_init_target(t, tname, hook)) < 0)
164                 goto err3;
165
166         spin_lock_bh(&ipt->tcf_lock);
167         if (ret != ACT_P_CREATED) {
168                 ipt_destroy_target(ipt->tcfi_t);
169                 kfree(ipt->tcfi_tname);
170                 kfree(ipt->tcfi_t);
171         }
172         ipt->tcfi_tname = tname;
173         ipt->tcfi_t     = t;
174         ipt->tcfi_hook  = hook;
175         spin_unlock_bh(&ipt->tcf_lock);
176         if (ret == ACT_P_CREATED)
177                 tcf_hash_insert(pc, &ipt_hash_info);
178         return ret;
179
180 err3:
181         kfree(t);
182 err2:
183         kfree(tname);
184 err1:
185         kfree(pc);
186         return err;
187 }
188
189 static int tcf_ipt_cleanup(struct tc_action *a, int bind)
190 {
191         struct tcf_ipt *ipt = a->priv;
192         return tcf_ipt_release(ipt, bind);
193 }
194
195 static int tcf_ipt(struct sk_buff *skb, struct tc_action *a,
196                    struct tcf_result *res)
197 {
198         int ret = 0, result = 0;
199         struct tcf_ipt *ipt = a->priv;
200
201         if (skb_cloned(skb)) {
202                 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
203                         return TC_ACT_UNSPEC;
204         }
205
206         spin_lock(&ipt->tcf_lock);
207
208         ipt->tcf_tm.lastuse = jiffies;
209         ipt->tcf_bstats.bytes += skb->len;
210         ipt->tcf_bstats.packets++;
211
212         /* yes, we have to worry about both in and out dev
213          worry later - danger - this API seems to have changed
214          from earlier kernels */
215
216         /* iptables targets take a double skb pointer in case the skb
217          * needs to be replaced. We don't own the skb, so this must not
218          * happen. The pskb_expand_head above should make sure of this */
219         ret = ipt->tcfi_t->u.kernel.target->target(&skb, skb->dev, NULL,
220                                                    ipt->tcfi_hook,
221                                                    ipt->tcfi_t->u.kernel.target,
222                                                    ipt->tcfi_t->data);
223         switch (ret) {
224         case NF_ACCEPT:
225                 result = TC_ACT_OK;
226                 break;
227         case NF_DROP:
228                 result = TC_ACT_SHOT;
229                 ipt->tcf_qstats.drops++;
230                 break;
231         case IPT_CONTINUE:
232                 result = TC_ACT_PIPE;
233                 break;
234         default:
235                 if (net_ratelimit())
236                         printk("Bogus netfilter code %d assume ACCEPT\n", ret);
237                 result = TC_POLICE_OK;
238                 break;
239         }
240         spin_unlock(&ipt->tcf_lock);
241         return result;
242
243 }
244
245 static int tcf_ipt_dump(struct sk_buff *skb, struct tc_action *a, int bind, int ref)
246 {
247         unsigned char *b = skb->tail;
248         struct tcf_ipt *ipt = a->priv;
249         struct ipt_entry_target *t;
250         struct tcf_t tm;
251         struct tc_cnt c;
252
253         /* for simple targets kernel size == user size
254         ** user name = target name
255         ** for foolproof you need to not assume this
256         */
257
258         t = kmemdup(ipt->tcfi_t, ipt->tcfi_t->u.user.target_size, GFP_ATOMIC);
259         if (unlikely(!t))
260                 goto rtattr_failure;
261
262         c.bindcnt = ipt->tcf_bindcnt - bind;
263         c.refcnt = ipt->tcf_refcnt - ref;
264         strcpy(t->u.user.name, ipt->tcfi_t->u.kernel.target->name);
265
266         RTA_PUT(skb, TCA_IPT_TARG, ipt->tcfi_t->u.user.target_size, t);
267         RTA_PUT(skb, TCA_IPT_INDEX, 4, &ipt->tcf_index);
268         RTA_PUT(skb, TCA_IPT_HOOK, 4, &ipt->tcfi_hook);
269         RTA_PUT(skb, TCA_IPT_CNT, sizeof(struct tc_cnt), &c);
270         RTA_PUT(skb, TCA_IPT_TABLE, IFNAMSIZ, ipt->tcfi_tname);
271         tm.install = jiffies_to_clock_t(jiffies - ipt->tcf_tm.install);
272         tm.lastuse = jiffies_to_clock_t(jiffies - ipt->tcf_tm.lastuse);
273         tm.expires = jiffies_to_clock_t(ipt->tcf_tm.expires);
274         RTA_PUT(skb, TCA_IPT_TM, sizeof (tm), &tm);
275         kfree(t);
276         return skb->len;
277
278 rtattr_failure:
279         skb_trim(skb, b - skb->data);
280         kfree(t);
281         return -1;
282 }
283
284 static struct tc_action_ops act_ipt_ops = {
285         .kind           =       "ipt",
286         .hinfo          =       &ipt_hash_info,
287         .type           =       TCA_ACT_IPT,
288         .capab          =       TCA_CAP_NONE,
289         .owner          =       THIS_MODULE,
290         .act            =       tcf_ipt,
291         .dump           =       tcf_ipt_dump,
292         .cleanup        =       tcf_ipt_cleanup,
293         .lookup         =       tcf_hash_search,
294         .init           =       tcf_ipt_init,
295         .walk           =       tcf_generic_walker
296 };
297
298 MODULE_AUTHOR("Jamal Hadi Salim(2002-4)");
299 MODULE_DESCRIPTION("Iptables target actions");
300 MODULE_LICENSE("GPL");
301
302 static int __init ipt_init_module(void)
303 {
304         return tcf_register_action(&act_ipt_ops);
305 }
306
307 static void __exit ipt_cleanup_module(void)
308 {
309         tcf_unregister_action(&act_ipt_ops);
310 }
311
312 module_init(ipt_init_module);
313 module_exit(ipt_cleanup_module);