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 static unsigned int ipt_net_id;
32 static struct tc_action_ops act_ipt_ops;
33
34 static unsigned int xt_net_id;
35 static struct tc_action_ops act_xt_ops;
36
ipt_init_target(struct net * net,struct xt_entry_target * t,char * table,unsigned int hook)37 static int ipt_init_target(struct net *net, struct xt_entry_target *t,
38 char *table, unsigned int hook)
39 {
40 struct xt_tgchk_param par;
41 struct xt_target *target;
42 struct ipt_entry e = {};
43 int ret = 0;
44
45 target = xt_request_find_target(AF_INET, t->u.user.name,
46 t->u.user.revision);
47 if (IS_ERR(target))
48 return PTR_ERR(target);
49
50 t->u.kernel.target = target;
51 memset(&par, 0, sizeof(par));
52 par.net = net;
53 par.table = table;
54 par.entryinfo = &e;
55 par.target = target;
56 par.targinfo = t->data;
57 par.hook_mask = hook;
58 par.family = NFPROTO_IPV4;
59
60 ret = xt_check_target(&par, t->u.target_size - sizeof(*t), 0, false);
61 if (ret < 0) {
62 module_put(t->u.kernel.target->me);
63 return ret;
64 }
65 return 0;
66 }
67
ipt_destroy_target(struct xt_entry_target * t,struct net * net)68 static void ipt_destroy_target(struct xt_entry_target *t, struct net *net)
69 {
70 struct xt_tgdtor_param par = {
71 .target = t->u.kernel.target,
72 .targinfo = t->data,
73 .family = NFPROTO_IPV4,
74 .net = net,
75 };
76 if (par.target->destroy != NULL)
77 par.target->destroy(&par);
78 module_put(par.target->me);
79 }
80
tcf_ipt_release(struct tc_action * a,int bind)81 static void tcf_ipt_release(struct tc_action *a, int bind)
82 {
83 struct tcf_ipt *ipt = to_ipt(a);
84
85 if (ipt->tcfi_t) {
86 ipt_destroy_target(ipt->tcfi_t, a->idrinfo->net);
87 kfree(ipt->tcfi_t);
88 }
89 kfree(ipt->tcfi_tname);
90 }
91
92 static const struct nla_policy ipt_policy[TCA_IPT_MAX + 1] = {
93 [TCA_IPT_TABLE] = { .type = NLA_STRING, .len = IFNAMSIZ },
94 [TCA_IPT_HOOK] = { .type = NLA_U32 },
95 [TCA_IPT_INDEX] = { .type = NLA_U32 },
96 [TCA_IPT_TARG] = { .len = sizeof(struct xt_entry_target) },
97 };
98
__tcf_ipt_init(struct net * net,unsigned int id,struct nlattr * nla,struct nlattr * est,struct tc_action ** a,const struct tc_action_ops * ops,int ovr,int bind)99 static int __tcf_ipt_init(struct net *net, unsigned int id, struct nlattr *nla,
100 struct nlattr *est, struct tc_action **a,
101 const struct tc_action_ops *ops, int ovr, int bind)
102 {
103 struct tc_action_net *tn = net_generic(net, id);
104 struct nlattr *tb[TCA_IPT_MAX + 1];
105 struct tcf_ipt *ipt;
106 struct xt_entry_target *td, *t;
107 char *tname;
108 bool exists = false;
109 int ret = 0, err;
110 u32 hook = 0;
111 u32 index = 0;
112
113 if (nla == NULL)
114 return -EINVAL;
115
116 err = nla_parse_nested(tb, TCA_IPT_MAX, nla, ipt_policy, NULL);
117 if (err < 0)
118 return err;
119
120 if (tb[TCA_IPT_INDEX] != NULL)
121 index = nla_get_u32(tb[TCA_IPT_INDEX]);
122
123 exists = tcf_idr_check(tn, index, a, bind);
124 if (exists && bind)
125 return 0;
126
127 if (tb[TCA_IPT_HOOK] == NULL || tb[TCA_IPT_TARG] == NULL) {
128 if (exists)
129 tcf_idr_release(*a, bind);
130 return -EINVAL;
131 }
132
133 td = (struct xt_entry_target *)nla_data(tb[TCA_IPT_TARG]);
134 if (nla_len(tb[TCA_IPT_TARG]) < td->u.target_size) {
135 if (exists)
136 tcf_idr_release(*a, bind);
137 return -EINVAL;
138 }
139
140 if (!exists) {
141 ret = tcf_idr_create(tn, index, est, a, ops, bind,
142 false);
143 if (ret)
144 return ret;
145 ret = ACT_P_CREATED;
146 } else {
147 if (bind)/* dont override defaults */
148 return 0;
149 tcf_idr_release(*a, bind);
150
151 if (!ovr)
152 return -EEXIST;
153 }
154 hook = nla_get_u32(tb[TCA_IPT_HOOK]);
155
156 err = -ENOMEM;
157 tname = kmalloc(IFNAMSIZ, GFP_KERNEL);
158 if (unlikely(!tname))
159 goto err1;
160 if (tb[TCA_IPT_TABLE] == NULL ||
161 nla_strlcpy(tname, tb[TCA_IPT_TABLE], IFNAMSIZ) >= IFNAMSIZ)
162 strcpy(tname, "mangle");
163
164 t = kmemdup(td, td->u.target_size, GFP_KERNEL);
165 if (unlikely(!t))
166 goto err2;
167
168 err = ipt_init_target(net, t, tname, hook);
169 if (err < 0)
170 goto err3;
171
172 ipt = to_ipt(*a);
173
174 spin_lock_bh(&ipt->tcf_lock);
175 if (ret != ACT_P_CREATED) {
176 ipt_destroy_target(ipt->tcfi_t, net);
177 kfree(ipt->tcfi_tname);
178 kfree(ipt->tcfi_t);
179 }
180 ipt->tcfi_tname = tname;
181 ipt->tcfi_t = t;
182 ipt->tcfi_hook = hook;
183 spin_unlock_bh(&ipt->tcf_lock);
184 if (ret == ACT_P_CREATED)
185 tcf_idr_insert(tn, *a);
186 return ret;
187
188 err3:
189 kfree(t);
190 err2:
191 kfree(tname);
192 err1:
193 if (ret == ACT_P_CREATED)
194 tcf_idr_release(*a, bind);
195 return err;
196 }
197
tcf_ipt_init(struct net * net,struct nlattr * nla,struct nlattr * est,struct tc_action ** a,int ovr,int bind)198 static int tcf_ipt_init(struct net *net, struct nlattr *nla,
199 struct nlattr *est, struct tc_action **a, int ovr,
200 int bind)
201 {
202 return __tcf_ipt_init(net, ipt_net_id, nla, est, a, &act_ipt_ops, ovr,
203 bind);
204 }
205
tcf_xt_init(struct net * net,struct nlattr * nla,struct nlattr * est,struct tc_action ** a,int ovr,int bind)206 static int tcf_xt_init(struct net *net, struct nlattr *nla,
207 struct nlattr *est, struct tc_action **a, int ovr,
208 int bind)
209 {
210 return __tcf_ipt_init(net, xt_net_id, nla, est, a, &act_xt_ops, ovr,
211 bind);
212 }
213
tcf_ipt(struct sk_buff * skb,const struct tc_action * a,struct tcf_result * res)214 static int tcf_ipt(struct sk_buff *skb, const struct tc_action *a,
215 struct tcf_result *res)
216 {
217 int ret = 0, result = 0;
218 struct tcf_ipt *ipt = to_ipt(a);
219 struct xt_action_param par;
220 struct nf_hook_state state = {
221 .net = dev_net(skb->dev),
222 .in = skb->dev,
223 .hook = ipt->tcfi_hook,
224 .pf = NFPROTO_IPV4,
225 };
226
227 if (skb_unclone(skb, GFP_ATOMIC))
228 return TC_ACT_UNSPEC;
229
230 spin_lock(&ipt->tcf_lock);
231
232 tcf_lastuse_update(&ipt->tcf_tm);
233 bstats_update(&ipt->tcf_bstats, skb);
234
235 /* yes, we have to worry about both in and out dev
236 * worry later - danger - this API seems to have changed
237 * from earlier kernels
238 */
239 par.state = &state;
240 par.target = ipt->tcfi_t->u.kernel.target;
241 par.targinfo = ipt->tcfi_t->data;
242 ret = par.target->target(skb, &par);
243
244 switch (ret) {
245 case NF_ACCEPT:
246 result = TC_ACT_OK;
247 break;
248 case NF_DROP:
249 result = TC_ACT_SHOT;
250 ipt->tcf_qstats.drops++;
251 break;
252 case XT_CONTINUE:
253 result = TC_ACT_PIPE;
254 break;
255 default:
256 net_notice_ratelimited("tc filter: Bogus netfilter code %d assume ACCEPT\n",
257 ret);
258 result = TC_ACT_OK;
259 break;
260 }
261 spin_unlock(&ipt->tcf_lock);
262 return result;
263
264 }
265
tcf_ipt_dump(struct sk_buff * skb,struct tc_action * a,int bind,int ref)266 static int tcf_ipt_dump(struct sk_buff *skb, struct tc_action *a, int bind,
267 int ref)
268 {
269 unsigned char *b = skb_tail_pointer(skb);
270 struct tcf_ipt *ipt = to_ipt(a);
271 struct xt_entry_target *t;
272 struct tcf_t tm;
273 struct tc_cnt c;
274
275 /* for simple targets kernel size == user size
276 * user name = target name
277 * for foolproof you need to not assume this
278 */
279
280 t = kmemdup(ipt->tcfi_t, ipt->tcfi_t->u.user.target_size, GFP_ATOMIC);
281 if (unlikely(!t))
282 goto nla_put_failure;
283
284 c.bindcnt = ipt->tcf_bindcnt - bind;
285 c.refcnt = ipt->tcf_refcnt - ref;
286 strcpy(t->u.user.name, ipt->tcfi_t->u.kernel.target->name);
287
288 if (nla_put(skb, TCA_IPT_TARG, ipt->tcfi_t->u.user.target_size, t) ||
289 nla_put_u32(skb, TCA_IPT_INDEX, ipt->tcf_index) ||
290 nla_put_u32(skb, TCA_IPT_HOOK, ipt->tcfi_hook) ||
291 nla_put(skb, TCA_IPT_CNT, sizeof(struct tc_cnt), &c) ||
292 nla_put_string(skb, TCA_IPT_TABLE, ipt->tcfi_tname))
293 goto nla_put_failure;
294
295 tcf_tm_dump(&tm, &ipt->tcf_tm);
296 if (nla_put_64bit(skb, TCA_IPT_TM, sizeof(tm), &tm, TCA_IPT_PAD))
297 goto nla_put_failure;
298
299 kfree(t);
300 return skb->len;
301
302 nla_put_failure:
303 nlmsg_trim(skb, b);
304 kfree(t);
305 return -1;
306 }
307
tcf_ipt_walker(struct net * net,struct sk_buff * skb,struct netlink_callback * cb,int type,const struct tc_action_ops * ops)308 static int tcf_ipt_walker(struct net *net, struct sk_buff *skb,
309 struct netlink_callback *cb, int type,
310 const struct tc_action_ops *ops)
311 {
312 struct tc_action_net *tn = net_generic(net, ipt_net_id);
313
314 return tcf_generic_walker(tn, skb, cb, type, ops);
315 }
316
tcf_ipt_search(struct net * net,struct tc_action ** a,u32 index)317 static int tcf_ipt_search(struct net *net, struct tc_action **a, u32 index)
318 {
319 struct tc_action_net *tn = net_generic(net, ipt_net_id);
320
321 return tcf_idr_search(tn, a, index);
322 }
323
324 static struct tc_action_ops act_ipt_ops = {
325 .kind = "ipt",
326 .type = TCA_ACT_IPT,
327 .owner = THIS_MODULE,
328 .act = tcf_ipt,
329 .dump = tcf_ipt_dump,
330 .cleanup = tcf_ipt_release,
331 .init = tcf_ipt_init,
332 .walk = tcf_ipt_walker,
333 .lookup = tcf_ipt_search,
334 .size = sizeof(struct tcf_ipt),
335 };
336
ipt_init_net(struct net * net)337 static __net_init int ipt_init_net(struct net *net)
338 {
339 struct tc_action_net *tn = net_generic(net, ipt_net_id);
340
341 return tc_action_net_init(net, tn, &act_ipt_ops);
342 }
343
ipt_exit_net(struct net * net)344 static void __net_exit ipt_exit_net(struct net *net)
345 {
346 struct tc_action_net *tn = net_generic(net, ipt_net_id);
347
348 tc_action_net_exit(tn);
349 }
350
351 static struct pernet_operations ipt_net_ops = {
352 .init = ipt_init_net,
353 .exit = ipt_exit_net,
354 .id = &ipt_net_id,
355 .size = sizeof(struct tc_action_net),
356 };
357
tcf_xt_walker(struct net * net,struct sk_buff * skb,struct netlink_callback * cb,int type,const struct tc_action_ops * ops)358 static int tcf_xt_walker(struct net *net, struct sk_buff *skb,
359 struct netlink_callback *cb, int type,
360 const struct tc_action_ops *ops)
361 {
362 struct tc_action_net *tn = net_generic(net, xt_net_id);
363
364 return tcf_generic_walker(tn, skb, cb, type, ops);
365 }
366
tcf_xt_search(struct net * net,struct tc_action ** a,u32 index)367 static int tcf_xt_search(struct net *net, struct tc_action **a, u32 index)
368 {
369 struct tc_action_net *tn = net_generic(net, xt_net_id);
370
371 return tcf_idr_search(tn, a, index);
372 }
373
374 static struct tc_action_ops act_xt_ops = {
375 .kind = "xt",
376 .type = TCA_ACT_XT,
377 .owner = THIS_MODULE,
378 .act = tcf_ipt,
379 .dump = tcf_ipt_dump,
380 .cleanup = tcf_ipt_release,
381 .init = tcf_xt_init,
382 .walk = tcf_xt_walker,
383 .lookup = tcf_xt_search,
384 .size = sizeof(struct tcf_ipt),
385 };
386
xt_init_net(struct net * net)387 static __net_init int xt_init_net(struct net *net)
388 {
389 struct tc_action_net *tn = net_generic(net, xt_net_id);
390
391 return tc_action_net_init(net, tn, &act_xt_ops);
392 }
393
xt_exit_net(struct net * net)394 static void __net_exit xt_exit_net(struct net *net)
395 {
396 struct tc_action_net *tn = net_generic(net, xt_net_id);
397
398 tc_action_net_exit(tn);
399 }
400
401 static struct pernet_operations xt_net_ops = {
402 .init = xt_init_net,
403 .exit = xt_exit_net,
404 .id = &xt_net_id,
405 .size = sizeof(struct tc_action_net),
406 };
407
408 MODULE_AUTHOR("Jamal Hadi Salim(2002-13)");
409 MODULE_DESCRIPTION("Iptables target actions");
410 MODULE_LICENSE("GPL");
411 MODULE_ALIAS("act_xt");
412
ipt_init_module(void)413 static int __init ipt_init_module(void)
414 {
415 int ret1, ret2;
416
417 ret1 = tcf_register_action(&act_xt_ops, &xt_net_ops);
418 if (ret1 < 0)
419 pr_err("Failed to load xt action\n");
420
421 ret2 = tcf_register_action(&act_ipt_ops, &ipt_net_ops);
422 if (ret2 < 0)
423 pr_err("Failed to load ipt action\n");
424
425 if (ret1 < 0 && ret2 < 0) {
426 return ret1;
427 } else
428 return 0;
429 }
430
ipt_cleanup_module(void)431 static void __exit ipt_cleanup_module(void)
432 {
433 tcf_unregister_action(&act_ipt_ops, &ipt_net_ops);
434 tcf_unregister_action(&act_xt_ops, &xt_net_ops);
435 }
436
437 module_init(ipt_init_module);
438 module_exit(ipt_cleanup_module);
439