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 <linux/types.h>
15 #include <linux/kernel.h>
16 #include <linux/string.h>
17 #include <linux/errno.h>
18 #include <linux/skbuff.h>
19 #include <linux/rtnetlink.h>
20 #include <linux/module.h>
21 #include <linux/init.h>
22 #include <net/netlink.h>
23 #include <net/pkt_sched.h>
24 #include <linux/tc_act/tc_ipt.h>
25 #include <net/tc_act/tc_ipt.h>
26
27 #include <linux/netfilter_ipv4/ip_tables.h>
28
29
30 #define IPT_TAB_MASK 15
31 static struct tcf_common *tcf_ipt_ht[IPT_TAB_MASK + 1];
32 static u32 ipt_idx_gen;
33 static DEFINE_RWLOCK(ipt_lock);
34
35 static struct tcf_hashinfo ipt_hash_info = {
36 .htab = tcf_ipt_ht,
37 .hmask = IPT_TAB_MASK,
38 .lock = &ipt_lock,
39 };
40
41 static int ipt_init_target(struct ipt_entry_target *t, char *table, unsigned int hook)
42 {
43 struct xt_target *target;
44 int ret = 0;
45
46 target = xt_request_find_target(AF_INET, t->u.user.name,
47 t->u.user.revision);
48 if (!target)
49 return -ENOENT;
50
51 t->u.kernel.target = target;
52
53 ret = xt_check_target(target, AF_INET, t->u.target_size - sizeof(*t),
54 table, hook, 0, 0);
55 if (ret) {
56 module_put(t->u.kernel.target->me);
57 return ret;
58 }
59 if (t->u.kernel.target->checkentry
60 && !t->u.kernel.target->checkentry(table, NULL,
61 t->u.kernel.target, t->data,
62 hook)) {
63 module_put(t->u.kernel.target->me);
64 ret = -EINVAL;
65 }
66
67 return ret;
68 }
69
70 static void ipt_destroy_target(struct ipt_entry_target *t)
71 {
72 if (t->u.kernel.target->destroy)
73 t->u.kernel.target->destroy(t->u.kernel.target, t->data);
74 module_put(t->u.kernel.target->me);
75 }
76
77 static int tcf_ipt_release(struct tcf_ipt *ipt, int bind)
78 {
79 int ret = 0;
80 if (ipt) {
81 if (bind)
82 ipt->tcf_bindcnt--;
83 ipt->tcf_refcnt--;
84 if (ipt->tcf_bindcnt <= 0 && ipt->tcf_refcnt <= 0) {
85 ipt_destroy_target(ipt->tcfi_t);
86 kfree(ipt->tcfi_tname);
87 kfree(ipt->tcfi_t);
88 tcf_hash_destroy(&ipt->common, &ipt_hash_info);
89 ret = ACT_P_DELETED;
90 }
91 }
92 return ret;
93 }
94
95 static const struct nla_policy ipt_policy[TCA_IPT_MAX + 1] = {
96 [TCA_IPT_TABLE] = { .type = NLA_STRING, .len = IFNAMSIZ },
97 [TCA_IPT_HOOK] = { .type = NLA_U32 },
98 [TCA_IPT_INDEX] = { .type = NLA_U32 },
99 [TCA_IPT_TARG] = { .len = sizeof(struct ipt_entry_target) },
100 };
101
102 static int tcf_ipt_init(struct nlattr *nla, struct nlattr *est,
103 struct tc_action *a, int ovr, int bind)
104 {
105 struct nlattr *tb[TCA_IPT_MAX + 1];
106 struct tcf_ipt *ipt;
107 struct tcf_common *pc;
108 struct ipt_entry_target *td, *t;
109 char *tname;
110 int ret = 0, err;
111 u32 hook = 0;
112 u32 index = 0;
113
114 if (nla == NULL)
115 return -EINVAL;
116
117 err = nla_parse_nested(tb, TCA_IPT_MAX, nla, ipt_policy);
118 if (err < 0)
119 return err;
120
121 if (tb[TCA_IPT_HOOK] == NULL)
122 return -EINVAL;
123 if (tb[TCA_IPT_TARG] == NULL)
124 return -EINVAL;
125
126 td = (struct ipt_entry_target *)nla_data(tb[TCA_IPT_TARG]);
127 if (nla_len(tb[TCA_IPT_TARG]) < td->u.target_size)
128 return -EINVAL;
129
130 if (tb[TCA_IPT_INDEX] != NULL)
131 index = nla_get_u32(tb[TCA_IPT_INDEX]);
132
133 pc = tcf_hash_check(index, a, bind, &ipt_hash_info);
134 if (!pc) {
135 pc = tcf_hash_create(index, est, a, sizeof(*ipt), bind,
136 &ipt_idx_gen, &ipt_hash_info);
137 if (unlikely(!pc))
138 return -ENOMEM;
139 ret = ACT_P_CREATED;
140 } else {
141 if (!ovr) {
142 tcf_ipt_release(to_ipt(pc), bind);
143 return -EEXIST;
144 }
145 }
146 ipt = to_ipt(pc);
147
148 hook = nla_get_u32(tb[TCA_IPT_HOOK]);
149
150 err = -ENOMEM;
151 tname = kmalloc(IFNAMSIZ, GFP_KERNEL);
152 if (unlikely(!tname))
153 goto err1;
154 if (tb[TCA_IPT_TABLE] == NULL ||
155 nla_strlcpy(tname, tb[TCA_IPT_TABLE], IFNAMSIZ) >= IFNAMSIZ)
156 strcpy(tname, "mangle");
157
158 t = kmemdup(td, td->u.target_size, GFP_KERNEL);
159 if (unlikely(!t))
160 goto err2;
161
162 if ((err = ipt_init_target(t, tname, hook)) < 0)
163 goto err3;
164
165 spin_lock_bh(&ipt->tcf_lock);
166 if (ret != ACT_P_CREATED) {
167 ipt_destroy_target(ipt->tcfi_t);
168 kfree(ipt->tcfi_tname);
169 kfree(ipt->tcfi_t);
170 }
171 ipt->tcfi_tname = tname;
172 ipt->tcfi_t = t;
173 ipt->tcfi_hook = hook;
174 spin_unlock_bh(&ipt->tcf_lock);
175 if (ret == ACT_P_CREATED)
176 tcf_hash_insert(pc, &ipt_hash_info);
177 return ret;
178
179 err3:
180 kfree(t);
181 err2:
182 kfree(tname);
183 err1:
184 kfree(pc);
185 return err;
186 }
187
188 static int tcf_ipt_cleanup(struct tc_action *a, int bind)
189 {
190 struct tcf_ipt *ipt = a->priv;
191 return tcf_ipt_release(ipt, bind);
192 }
193
194 static int tcf_ipt(struct sk_buff *skb, struct tc_action *a,
195 struct tcf_result *res)
196 {
197 int ret = 0, result = 0;
198 struct tcf_ipt *ipt = a->priv;
199
200 if (skb_cloned(skb)) {
201 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
202 return TC_ACT_UNSPEC;
203 }
204
205 spin_lock(&ipt->tcf_lock);
206
207 ipt->tcf_tm.lastuse = jiffies;
208 ipt->tcf_bstats.bytes += skb->len;
209 ipt->tcf_bstats.packets++;
210
211 /* yes, we have to worry about both in and out dev
212 worry later - danger - this API seems to have changed
213 from earlier kernels */
214 ret = ipt->tcfi_t->u.kernel.target->target(skb, skb->dev, NULL,
215 ipt->tcfi_hook,
216 ipt->tcfi_t->u.kernel.target,
217 ipt->tcfi_t->data);
218 switch (ret) {
219 case NF_ACCEPT:
220 result = TC_ACT_OK;
221 break;
222 case NF_DROP:
223 result = TC_ACT_SHOT;
224 ipt->tcf_qstats.drops++;
225 break;
226 case IPT_CONTINUE:
227 result = TC_ACT_PIPE;
228 break;
229 default:
230 if (net_ratelimit())
231 printk("Bogus netfilter code %d assume ACCEPT\n", ret);
232 result = TC_POLICE_OK;
233 break;
234 }
235 spin_unlock(&ipt->tcf_lock);
236 return result;
237
238 }
239
240 static int tcf_ipt_dump(struct sk_buff *skb, struct tc_action *a, int bind, int ref)
241 {
242 unsigned char *b = skb_tail_pointer(skb);
243 struct tcf_ipt *ipt = a->priv;
244 struct ipt_entry_target *t;
245 struct tcf_t tm;
246 struct tc_cnt c;
247
248 /* for simple targets kernel size == user size
249 ** user name = target name
250 ** for foolproof you need to not assume this
251 */
252
253 t = kmemdup(ipt->tcfi_t, ipt->tcfi_t->u.user.target_size, GFP_ATOMIC);
254 if (unlikely(!t))
255 goto nla_put_failure;
256
257 c.bindcnt = ipt->tcf_bindcnt - bind;
258 c.refcnt = ipt->tcf_refcnt - ref;
259 strcpy(t->u.user.name, ipt->tcfi_t->u.kernel.target->name);
260
261 NLA_PUT(skb, TCA_IPT_TARG, ipt->tcfi_t->u.user.target_size, t);
262 NLA_PUT_U32(skb, TCA_IPT_INDEX, ipt->tcf_index);
263 NLA_PUT_U32(skb, TCA_IPT_HOOK, ipt->tcfi_hook);
264 NLA_PUT(skb, TCA_IPT_CNT, sizeof(struct tc_cnt), &c);
265 NLA_PUT_STRING(skb, TCA_IPT_TABLE, ipt->tcfi_tname);
266 tm.install = jiffies_to_clock_t(jiffies - ipt->tcf_tm.install);
267 tm.lastuse = jiffies_to_clock_t(jiffies - ipt->tcf_tm.lastuse);
268 tm.expires = jiffies_to_clock_t(ipt->tcf_tm.expires);
269 NLA_PUT(skb, TCA_IPT_TM, sizeof (tm), &tm);
270 kfree(t);
271 return skb->len;
272
273 nla_put_failure:
274 nlmsg_trim(skb, b);
275 kfree(t);
276 return -1;
277 }
278
279 static struct tc_action_ops act_ipt_ops = {
280 .kind = "ipt",
281 .hinfo = &ipt_hash_info,
282 .type = TCA_ACT_IPT,
283 .capab = TCA_CAP_NONE,
284 .owner = THIS_MODULE,
285 .act = tcf_ipt,
286 .dump = tcf_ipt_dump,
287 .cleanup = tcf_ipt_cleanup,
288 .lookup = tcf_hash_search,
289 .init = tcf_ipt_init,
290 .walk = tcf_generic_walker
291 };
292
293 MODULE_AUTHOR("Jamal Hadi Salim(2002-4)");
294 MODULE_DESCRIPTION("Iptables target actions");
295 MODULE_LICENSE("GPL");
296
297 static int __init ipt_init_module(void)
298 {
299 return tcf_register_action(&act_ipt_ops);
300 }
301
302 static void __exit ipt_cleanup_module(void)
303 {
304 tcf_unregister_action(&act_ipt_ops);
305 }
306
307 module_init(ipt_init_module);
308 module_exit(ipt_cleanup_module);
309
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