1 /*
2 * net/sched/act_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 (2002-13)
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 <linux/slab.h>
23 #include <net/netlink.h>
24 #include <net/pkt_sched.h>
25 #include <linux/tc_act/tc_ipt.h>
26 #include <net/tc_act/tc_ipt.h>
27
28 #include <linux/netfilter_ipv4/ip_tables.h>
29
30
31 #define IPT_TAB_MASK 15
32
33 static int ipt_init_target(struct xt_entry_target *t, char *table, unsigned int hook)
34 {
35 struct xt_tgchk_param par;
36 struct xt_target *target;
37 struct ipt_entry e = {};
38 int ret = 0;
39
40 target = xt_request_find_target(AF_INET, t->u.user.name,
41 t->u.user.revision);
42 if (IS_ERR(target))
43 return PTR_ERR(target);
44
45 t->u.kernel.target = target;
46 memset(&par, 0, sizeof(par));
47 par.table = table;
48 par.entryinfo = &e;
49 par.target = target;
50 par.targinfo = t->data;
51 par.hook_mask = hook;
52 par.family = NFPROTO_IPV4;
53
54 ret = xt_check_target(&par, t->u.target_size - sizeof(*t), 0, false);
55 if (ret < 0) {
56 module_put(t->u.kernel.target->me);
57 return ret;
58 }
59 return 0;
60 }
61
62 static void ipt_destroy_target(struct xt_entry_target *t)
63 {
64 struct xt_tgdtor_param par = {
65 .target = t->u.kernel.target,
66 .targinfo = t->data,
67 };
68 if (par.target->destroy != NULL)
69 par.target->destroy(&par);
70 module_put(par.target->me);
71 }
72
73 static void tcf_ipt_release(struct tc_action *a, int bind)
74 {
75 struct tcf_ipt *ipt = to_ipt(a);
76 ipt_destroy_target(ipt->tcfi_t);
77 kfree(ipt->tcfi_tname);
78 kfree(ipt->tcfi_t);
79 }
80
81 static const struct nla_policy ipt_policy[TCA_IPT_MAX + 1] = {
82 [TCA_IPT_TABLE] = { .type = NLA_STRING, .len = IFNAMSIZ },
83 [TCA_IPT_HOOK] = { .type = NLA_U32 },
84 [TCA_IPT_INDEX] = { .type = NLA_U32 },
85 [TCA_IPT_TARG] = { .len = sizeof(struct xt_entry_target) },
86 };
87
88 static int tcf_ipt_init(struct net *net, struct nlattr *nla, struct nlattr *est,
89 struct tc_action *a, int ovr, int bind)
90 {
91 struct nlattr *tb[TCA_IPT_MAX + 1];
92 struct tcf_ipt *ipt;
93 struct xt_entry_target *td, *t;
94 char *tname;
95 int ret = 0, err;
96 u32 hook = 0;
97 u32 index = 0;
98
99 if (nla == NULL)
100 return -EINVAL;
101
102 err = nla_parse_nested(tb, TCA_IPT_MAX, nla, ipt_policy);
103 if (err < 0)
104 return err;
105
106 if (tb[TCA_IPT_HOOK] == NULL)
107 return -EINVAL;
108 if (tb[TCA_IPT_TARG] == NULL)
109 return -EINVAL;
110
111 td = (struct xt_entry_target *)nla_data(tb[TCA_IPT_TARG]);
112 if (nla_len(tb[TCA_IPT_TARG]) < td->u.target_size)
113 return -EINVAL;
114
115 if (tb[TCA_IPT_INDEX] != NULL)
116 index = nla_get_u32(tb[TCA_IPT_INDEX]);
117
118 if (!tcf_hash_check(index, a, bind) ) {
119 ret = tcf_hash_create(index, est, a, sizeof(*ipt), bind, false);
120 if (ret)
121 return ret;
122 ret = ACT_P_CREATED;
123 } else {
124 if (bind)/* dont override defaults */
125 return 0;
126 tcf_hash_release(a, bind);
127
128 if (!ovr)
129 return -EEXIST;
130 }
131 ipt = to_ipt(a);
132
133 hook = nla_get_u32(tb[TCA_IPT_HOOK]);
134
135 err = -ENOMEM;
136 tname = kmalloc(IFNAMSIZ, GFP_KERNEL);
137 if (unlikely(!tname))
138 goto err1;
139 if (tb[TCA_IPT_TABLE] == NULL ||
140 nla_strlcpy(tname, tb[TCA_IPT_TABLE], IFNAMSIZ) >= IFNAMSIZ)
141 strcpy(tname, "mangle");
142
143 t = kmemdup(td, td->u.target_size, GFP_KERNEL);
144 if (unlikely(!t))
145 goto err2;
146
147 err = ipt_init_target(t, tname, hook);
148 if (err < 0)
149 goto err3;
150
151 spin_lock_bh(&ipt->tcf_lock);
152 if (ret != ACT_P_CREATED) {
153 ipt_destroy_target(ipt->tcfi_t);
154 kfree(ipt->tcfi_tname);
155 kfree(ipt->tcfi_t);
156 }
157 ipt->tcfi_tname = tname;
158 ipt->tcfi_t = t;
159 ipt->tcfi_hook = hook;
160 spin_unlock_bh(&ipt->tcf_lock);
161 if (ret == ACT_P_CREATED)
162 tcf_hash_insert(a);
163 return ret;
164
165 err3:
166 kfree(t);
167 err2:
168 kfree(tname);
169 err1:
170 if (ret == ACT_P_CREATED)
171 tcf_hash_cleanup(a, est);
172 return err;
173 }
174
175 static int tcf_ipt(struct sk_buff *skb, const struct tc_action *a,
176 struct tcf_result *res)
177 {
178 int ret = 0, result = 0;
179 struct tcf_ipt *ipt = a->priv;
180 struct xt_action_param par;
181
182 if (skb_unclone(skb, GFP_ATOMIC))
183 return TC_ACT_UNSPEC;
184
185 spin_lock(&ipt->tcf_lock);
186
187 ipt->tcf_tm.lastuse = jiffies;
188 bstats_update(&ipt->tcf_bstats, skb);
189
190 /* yes, we have to worry about both in and out dev
191 * worry later - danger - this API seems to have changed
192 * from earlier kernels
193 */
194 par.net = dev_net(skb->dev);
195 par.in = skb->dev;
196 par.out = NULL;
197 par.hooknum = ipt->tcfi_hook;
198 par.target = ipt->tcfi_t->u.kernel.target;
199 par.targinfo = ipt->tcfi_t->data;
200 ret = par.target->target(skb, &par);
201
202 switch (ret) {
203 case NF_ACCEPT:
204 result = TC_ACT_OK;
205 break;
206 case NF_DROP:
207 result = TC_ACT_SHOT;
208 ipt->tcf_qstats.drops++;
209 break;
210 case XT_CONTINUE:
211 result = TC_ACT_PIPE;
212 break;
213 default:
214 net_notice_ratelimited("tc filter: Bogus netfilter code %d assume ACCEPT\n",
215 ret);
216 result = TC_POLICE_OK;
217 break;
218 }
219 spin_unlock(&ipt->tcf_lock);
220 return result;
221
222 }
223
224 static int tcf_ipt_dump(struct sk_buff *skb, struct tc_action *a, int bind, int ref)
225 {
226 unsigned char *b = skb_tail_pointer(skb);
227 struct tcf_ipt *ipt = a->priv;
228 struct xt_entry_target *t;
229 struct tcf_t tm;
230 struct tc_cnt c;
231
232 /* for simple targets kernel size == user size
233 * user name = target name
234 * for foolproof you need to not assume this
235 */
236
237 t = kmemdup(ipt->tcfi_t, ipt->tcfi_t->u.user.target_size, GFP_ATOMIC);
238 if (unlikely(!t))
239 goto nla_put_failure;
240
241 c.bindcnt = ipt->tcf_bindcnt - bind;
242 c.refcnt = ipt->tcf_refcnt - ref;
243 strcpy(t->u.user.name, ipt->tcfi_t->u.kernel.target->name);
244
245 if (nla_put(skb, TCA_IPT_TARG, ipt->tcfi_t->u.user.target_size, t) ||
246 nla_put_u32(skb, TCA_IPT_INDEX, ipt->tcf_index) ||
247 nla_put_u32(skb, TCA_IPT_HOOK, ipt->tcfi_hook) ||
248 nla_put(skb, TCA_IPT_CNT, sizeof(struct tc_cnt), &c) ||
249 nla_put_string(skb, TCA_IPT_TABLE, ipt->tcfi_tname))
250 goto nla_put_failure;
251 tm.install = jiffies_to_clock_t(jiffies - ipt->tcf_tm.install);
252 tm.lastuse = jiffies_to_clock_t(jiffies - ipt->tcf_tm.lastuse);
253 tm.expires = jiffies_to_clock_t(ipt->tcf_tm.expires);
254 if (nla_put(skb, TCA_IPT_TM, sizeof (tm), &tm))
255 goto nla_put_failure;
256 kfree(t);
257 return skb->len;
258
259 nla_put_failure:
260 nlmsg_trim(skb, b);
261 kfree(t);
262 return -1;
263 }
264
265 static struct tc_action_ops act_ipt_ops = {
266 .kind = "ipt",
267 .type = TCA_ACT_IPT,
268 .owner = THIS_MODULE,
269 .act = tcf_ipt,
270 .dump = tcf_ipt_dump,
271 .cleanup = tcf_ipt_release,
272 .init = tcf_ipt_init,
273 };
274
275 static struct tc_action_ops act_xt_ops = {
276 .kind = "xt",
277 .type = TCA_ACT_XT,
278 .owner = THIS_MODULE,
279 .act = tcf_ipt,
280 .dump = tcf_ipt_dump,
281 .cleanup = tcf_ipt_release,
282 .init = tcf_ipt_init,
283 };
284
285 MODULE_AUTHOR("Jamal Hadi Salim(2002-13)");
286 MODULE_DESCRIPTION("Iptables target actions");
287 MODULE_LICENSE("GPL");
288 MODULE_ALIAS("act_xt");
289
290 static int __init ipt_init_module(void)
291 {
292 int ret1, ret2;
293
294 ret1 = tcf_register_action(&act_xt_ops, IPT_TAB_MASK);
295 if (ret1 < 0)
296 printk("Failed to load xt action\n");
297 ret2 = tcf_register_action(&act_ipt_ops, IPT_TAB_MASK);
298 if (ret2 < 0)
299 printk("Failed to load ipt action\n");
300
301 if (ret1 < 0 && ret2 < 0) {
302 return ret1;
303 } else
304 return 0;
305 }
306
307 static void __exit ipt_cleanup_module(void)
308 {
309 tcf_unregister_action(&act_xt_ops);
310 tcf_unregister_action(&act_ipt_ops);
311 }
312
313 module_init(ipt_init_module);
314 module_exit(ipt_cleanup_module);
315
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