xref: /openbmc/linux/net/sched/act_ipt.c (revision de2bdb3d)
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_net_id;
34 static struct tc_action_ops act_ipt_ops;
35 
36 static int xt_net_id;
37 static struct tc_action_ops act_xt_ops;
38 
39 static int ipt_init_target(struct xt_entry_target *t, char *table,
40 			   unsigned int hook)
41 {
42 	struct xt_tgchk_param par;
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 (IS_ERR(target))
49 		return PTR_ERR(target);
50 
51 	t->u.kernel.target = target;
52 	par.table     = table;
53 	par.entryinfo = NULL;
54 	par.target    = target;
55 	par.targinfo  = t->data;
56 	par.hook_mask = hook;
57 	par.family    = NFPROTO_IPV4;
58 
59 	ret = xt_check_target(&par, t->u.target_size - sizeof(*t), 0, false);
60 	if (ret < 0) {
61 		module_put(t->u.kernel.target->me);
62 		return ret;
63 	}
64 	return 0;
65 }
66 
67 static void ipt_destroy_target(struct xt_entry_target *t)
68 {
69 	struct xt_tgdtor_param par = {
70 		.target   = t->u.kernel.target,
71 		.targinfo = t->data,
72 		.family   = NFPROTO_IPV4,
73 	};
74 	if (par.target->destroy != NULL)
75 		par.target->destroy(&par);
76 	module_put(par.target->me);
77 }
78 
79 static void tcf_ipt_release(struct tc_action *a, int bind)
80 {
81 	struct tcf_ipt *ipt = to_ipt(a);
82 	ipt_destroy_target(ipt->tcfi_t);
83 	kfree(ipt->tcfi_tname);
84 	kfree(ipt->tcfi_t);
85 }
86 
87 static const struct nla_policy ipt_policy[TCA_IPT_MAX + 1] = {
88 	[TCA_IPT_TABLE]	= { .type = NLA_STRING, .len = IFNAMSIZ },
89 	[TCA_IPT_HOOK]	= { .type = NLA_U32 },
90 	[TCA_IPT_INDEX]	= { .type = NLA_U32 },
91 	[TCA_IPT_TARG]	= { .len = sizeof(struct xt_entry_target) },
92 };
93 
94 static int __tcf_ipt_init(struct tc_action_net *tn, struct nlattr *nla,
95 			  struct nlattr *est, struct tc_action **a,
96 			  const struct tc_action_ops *ops, int ovr, int bind)
97 {
98 	struct nlattr *tb[TCA_IPT_MAX + 1];
99 	struct tcf_ipt *ipt;
100 	struct xt_entry_target *td, *t;
101 	char *tname;
102 	bool exists = false;
103 	int ret = 0, err;
104 	u32 hook = 0;
105 	u32 index = 0;
106 
107 	if (nla == NULL)
108 		return -EINVAL;
109 
110 	err = nla_parse_nested(tb, TCA_IPT_MAX, nla, ipt_policy);
111 	if (err < 0)
112 		return err;
113 
114 	if (tb[TCA_IPT_INDEX] != NULL)
115 		index = nla_get_u32(tb[TCA_IPT_INDEX]);
116 
117 	exists = tcf_hash_check(tn, index, a, bind);
118 	if (exists && bind)
119 		return 0;
120 
121 	if (tb[TCA_IPT_HOOK] == NULL || tb[TCA_IPT_TARG] == NULL) {
122 		if (exists)
123 			tcf_hash_release(*a, bind);
124 		return -EINVAL;
125 	}
126 
127 	td = (struct xt_entry_target *)nla_data(tb[TCA_IPT_TARG]);
128 	if (nla_len(tb[TCA_IPT_TARG]) < td->u.target_size) {
129 		if (exists)
130 			tcf_hash_release(*a, bind);
131 		return -EINVAL;
132 	}
133 
134 	if (!exists) {
135 		ret = tcf_hash_create(tn, index, est, a, ops, bind,
136 				      false);
137 		if (ret)
138 			return ret;
139 		ret = ACT_P_CREATED;
140 	} else {
141 		if (bind)/* dont override defaults */
142 			return 0;
143 		tcf_hash_release(*a, bind);
144 
145 		if (!ovr)
146 			return -EEXIST;
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 	err = ipt_init_target(t, tname, hook);
163 	if (err < 0)
164 		goto err3;
165 
166 	ipt = to_ipt(*a);
167 
168 	spin_lock_bh(&ipt->tcf_lock);
169 	if (ret != ACT_P_CREATED) {
170 		ipt_destroy_target(ipt->tcfi_t);
171 		kfree(ipt->tcfi_tname);
172 		kfree(ipt->tcfi_t);
173 	}
174 	ipt->tcfi_tname = tname;
175 	ipt->tcfi_t     = t;
176 	ipt->tcfi_hook  = hook;
177 	spin_unlock_bh(&ipt->tcf_lock);
178 	if (ret == ACT_P_CREATED)
179 		tcf_hash_insert(tn, *a);
180 	return ret;
181 
182 err3:
183 	kfree(t);
184 err2:
185 	kfree(tname);
186 err1:
187 	if (ret == ACT_P_CREATED)
188 		tcf_hash_cleanup(*a, est);
189 	return err;
190 }
191 
192 static int tcf_ipt_init(struct net *net, struct nlattr *nla,
193 			struct nlattr *est, struct tc_action **a, int ovr,
194 			int bind)
195 {
196 	struct tc_action_net *tn = net_generic(net, ipt_net_id);
197 
198 	return __tcf_ipt_init(tn, nla, est, a, &act_ipt_ops, ovr, bind);
199 }
200 
201 static int tcf_xt_init(struct net *net, struct nlattr *nla,
202 		       struct nlattr *est, struct tc_action **a, int ovr,
203 		       int bind)
204 {
205 	struct tc_action_net *tn = net_generic(net, xt_net_id);
206 
207 	return __tcf_ipt_init(tn, nla, est, a, &act_xt_ops, ovr, bind);
208 }
209 
210 static int tcf_ipt(struct sk_buff *skb, const struct tc_action *a,
211 		   struct tcf_result *res)
212 {
213 	int ret = 0, result = 0;
214 	struct tcf_ipt *ipt = to_ipt(a);
215 	struct xt_action_param par;
216 
217 	if (skb_unclone(skb, GFP_ATOMIC))
218 		return TC_ACT_UNSPEC;
219 
220 	spin_lock(&ipt->tcf_lock);
221 
222 	tcf_lastuse_update(&ipt->tcf_tm);
223 	bstats_update(&ipt->tcf_bstats, skb);
224 
225 	/* yes, we have to worry about both in and out dev
226 	 * worry later - danger - this API seems to have changed
227 	 * from earlier kernels
228 	 */
229 	par.net	     = dev_net(skb->dev);
230 	par.in       = skb->dev;
231 	par.out      = NULL;
232 	par.hooknum  = ipt->tcfi_hook;
233 	par.target   = ipt->tcfi_t->u.kernel.target;
234 	par.targinfo = ipt->tcfi_t->data;
235 	par.family   = NFPROTO_IPV4;
236 	ret = par.target->target(skb, &par);
237 
238 	switch (ret) {
239 	case NF_ACCEPT:
240 		result = TC_ACT_OK;
241 		break;
242 	case NF_DROP:
243 		result = TC_ACT_SHOT;
244 		ipt->tcf_qstats.drops++;
245 		break;
246 	case XT_CONTINUE:
247 		result = TC_ACT_PIPE;
248 		break;
249 	default:
250 		net_notice_ratelimited("tc filter: Bogus netfilter code %d assume ACCEPT\n",
251 				       ret);
252 		result = TC_ACT_OK;
253 		break;
254 	}
255 	spin_unlock(&ipt->tcf_lock);
256 	return result;
257 
258 }
259 
260 static int tcf_ipt_dump(struct sk_buff *skb, struct tc_action *a, int bind,
261 			int ref)
262 {
263 	unsigned char *b = skb_tail_pointer(skb);
264 	struct tcf_ipt *ipt = to_ipt(a);
265 	struct xt_entry_target *t;
266 	struct tcf_t tm;
267 	struct tc_cnt c;
268 
269 	/* for simple targets kernel size == user size
270 	 * user name = target name
271 	 * for foolproof you need to not assume this
272 	 */
273 
274 	t = kmemdup(ipt->tcfi_t, ipt->tcfi_t->u.user.target_size, GFP_ATOMIC);
275 	if (unlikely(!t))
276 		goto nla_put_failure;
277 
278 	c.bindcnt = ipt->tcf_bindcnt - bind;
279 	c.refcnt = ipt->tcf_refcnt - ref;
280 	strcpy(t->u.user.name, ipt->tcfi_t->u.kernel.target->name);
281 
282 	if (nla_put(skb, TCA_IPT_TARG, ipt->tcfi_t->u.user.target_size, t) ||
283 	    nla_put_u32(skb, TCA_IPT_INDEX, ipt->tcf_index) ||
284 	    nla_put_u32(skb, TCA_IPT_HOOK, ipt->tcfi_hook) ||
285 	    nla_put(skb, TCA_IPT_CNT, sizeof(struct tc_cnt), &c) ||
286 	    nla_put_string(skb, TCA_IPT_TABLE, ipt->tcfi_tname))
287 		goto nla_put_failure;
288 
289 	tcf_tm_dump(&tm, &ipt->tcf_tm);
290 	if (nla_put_64bit(skb, TCA_IPT_TM, sizeof(tm), &tm, TCA_IPT_PAD))
291 		goto nla_put_failure;
292 
293 	kfree(t);
294 	return skb->len;
295 
296 nla_put_failure:
297 	nlmsg_trim(skb, b);
298 	kfree(t);
299 	return -1;
300 }
301 
302 static int tcf_ipt_walker(struct net *net, struct sk_buff *skb,
303 			  struct netlink_callback *cb, int type,
304 			  const struct tc_action_ops *ops)
305 {
306 	struct tc_action_net *tn = net_generic(net, ipt_net_id);
307 
308 	return tcf_generic_walker(tn, skb, cb, type, ops);
309 }
310 
311 static int tcf_ipt_search(struct net *net, struct tc_action **a, u32 index)
312 {
313 	struct tc_action_net *tn = net_generic(net, ipt_net_id);
314 
315 	return tcf_hash_search(tn, a, index);
316 }
317 
318 static struct tc_action_ops act_ipt_ops = {
319 	.kind		=	"ipt",
320 	.type		=	TCA_ACT_IPT,
321 	.owner		=	THIS_MODULE,
322 	.act		=	tcf_ipt,
323 	.dump		=	tcf_ipt_dump,
324 	.cleanup	=	tcf_ipt_release,
325 	.init		=	tcf_ipt_init,
326 	.walk		=	tcf_ipt_walker,
327 	.lookup		=	tcf_ipt_search,
328 	.size		=	sizeof(struct tcf_ipt),
329 };
330 
331 static __net_init int ipt_init_net(struct net *net)
332 {
333 	struct tc_action_net *tn = net_generic(net, ipt_net_id);
334 
335 	return tc_action_net_init(tn, &act_ipt_ops, IPT_TAB_MASK);
336 }
337 
338 static void __net_exit ipt_exit_net(struct net *net)
339 {
340 	struct tc_action_net *tn = net_generic(net, ipt_net_id);
341 
342 	tc_action_net_exit(tn);
343 }
344 
345 static struct pernet_operations ipt_net_ops = {
346 	.init = ipt_init_net,
347 	.exit = ipt_exit_net,
348 	.id   = &ipt_net_id,
349 	.size = sizeof(struct tc_action_net),
350 };
351 
352 static int tcf_xt_walker(struct net *net, struct sk_buff *skb,
353 			 struct netlink_callback *cb, int type,
354 			 const struct tc_action_ops *ops)
355 {
356 	struct tc_action_net *tn = net_generic(net, xt_net_id);
357 
358 	return tcf_generic_walker(tn, skb, cb, type, ops);
359 }
360 
361 static int tcf_xt_search(struct net *net, struct tc_action **a, u32 index)
362 {
363 	struct tc_action_net *tn = net_generic(net, xt_net_id);
364 
365 	return tcf_hash_search(tn, a, index);
366 }
367 
368 static struct tc_action_ops act_xt_ops = {
369 	.kind		=	"xt",
370 	.type		=	TCA_ACT_XT,
371 	.owner		=	THIS_MODULE,
372 	.act		=	tcf_ipt,
373 	.dump		=	tcf_ipt_dump,
374 	.cleanup	=	tcf_ipt_release,
375 	.init		=	tcf_xt_init,
376 	.walk		=	tcf_xt_walker,
377 	.lookup		=	tcf_xt_search,
378 	.size		=	sizeof(struct tcf_ipt),
379 };
380 
381 static __net_init int xt_init_net(struct net *net)
382 {
383 	struct tc_action_net *tn = net_generic(net, xt_net_id);
384 
385 	return tc_action_net_init(tn, &act_xt_ops, IPT_TAB_MASK);
386 }
387 
388 static void __net_exit xt_exit_net(struct net *net)
389 {
390 	struct tc_action_net *tn = net_generic(net, xt_net_id);
391 
392 	tc_action_net_exit(tn);
393 }
394 
395 static struct pernet_operations xt_net_ops = {
396 	.init = xt_init_net,
397 	.exit = xt_exit_net,
398 	.id   = &xt_net_id,
399 	.size = sizeof(struct tc_action_net),
400 };
401 
402 MODULE_AUTHOR("Jamal Hadi Salim(2002-13)");
403 MODULE_DESCRIPTION("Iptables target actions");
404 MODULE_LICENSE("GPL");
405 MODULE_ALIAS("act_xt");
406 
407 static int __init ipt_init_module(void)
408 {
409 	int ret1, ret2;
410 
411 	ret1 = tcf_register_action(&act_xt_ops, &xt_net_ops);
412 	if (ret1 < 0)
413 		pr_err("Failed to load xt action\n");
414 
415 	ret2 = tcf_register_action(&act_ipt_ops, &ipt_net_ops);
416 	if (ret2 < 0)
417 		pr_err("Failed to load ipt action\n");
418 
419 	if (ret1 < 0 && ret2 < 0) {
420 		return ret1;
421 	} else
422 		return 0;
423 }
424 
425 static void __exit ipt_cleanup_module(void)
426 {
427 	tcf_unregister_action(&act_ipt_ops, &ipt_net_ops);
428 	tcf_unregister_action(&act_xt_ops, &xt_net_ops);
429 }
430 
431 module_init(ipt_init_module);
432 module_exit(ipt_cleanup_module);
433