xref: /linux/net/sched/cls_fw.c (revision 8f8d5745bb520c76b81abef4a2cb3023d0313bfd) 
1 /*
2  * net/sched/cls_fw.c	Classifier mapping ipchains' fwmark to traffic class.
3  *
4  *		This program is free software; you can redistribute it and/or
5  *		modify it under the terms of the GNU General Public License
6  *		as published by the Free Software Foundation; either version
7  *		2 of the License, or (at your option) any later version.
8  *
9  * Authors:	Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
10  *
11  * Changes:
12  * Karlis Peisenieks <karlis@mt.lv> : 990415 : fw_walk off by one
13  * Karlis Peisenieks <karlis@mt.lv> : 990415 : fw_delete killed all the filter (and kernel).
14  * Alex <alex@pilotsoft.com> : 2004xxyy: Added Action extension
15  *
16  * JHS: We should remove the CONFIG_NET_CLS_IND from here
17  * eventually when the meta match extension is made available
18  *
19  */
20 
21 #include <linux/module.h>
22 #include <linux/slab.h>
23 #include <linux/types.h>
24 #include <linux/kernel.h>
25 #include <linux/string.h>
26 #include <linux/errno.h>
27 #include <linux/skbuff.h>
28 #include <net/netlink.h>
29 #include <net/act_api.h>
30 #include <net/pkt_cls.h>
31 #include <net/sch_generic.h>
32 
33 #define HTSIZE 256
34 
35 struct fw_head {
36 	u32			mask;
37 	struct fw_filter __rcu	*ht[HTSIZE];
38 	struct rcu_head		rcu;
39 };
40 
41 struct fw_filter {
42 	struct fw_filter __rcu	*next;
43 	u32			id;
44 	struct tcf_result	res;
45 #ifdef CONFIG_NET_CLS_IND
46 	int			ifindex;
47 #endif /* CONFIG_NET_CLS_IND */
48 	struct tcf_exts		exts;
49 	struct tcf_proto	*tp;
50 	struct rcu_work		rwork;
51 };
52 
53 static u32 fw_hash(u32 handle)
54 {
55 	handle ^= (handle >> 16);
56 	handle ^= (handle >> 8);
57 	return handle % HTSIZE;
58 }
59 
60 static int fw_classify(struct sk_buff *skb, const struct tcf_proto *tp,
61 		       struct tcf_result *res)
62 {
63 	struct fw_head *head = rcu_dereference_bh(tp->root);
64 	struct fw_filter *f;
65 	int r;
66 	u32 id = skb->mark;
67 
68 	if (head != NULL) {
69 		id &= head->mask;
70 
71 		for (f = rcu_dereference_bh(head->ht[fw_hash(id)]); f;
72 		     f = rcu_dereference_bh(f->next)) {
73 			if (f->id == id) {
74 				*res = f->res;
75 #ifdef CONFIG_NET_CLS_IND
76 				if (!tcf_match_indev(skb, f->ifindex))
77 					continue;
78 #endif /* CONFIG_NET_CLS_IND */
79 				r = tcf_exts_exec(skb, &f->exts, res);
80 				if (r < 0)
81 					continue;
82 
83 				return r;
84 			}
85 		}
86 	} else {
87 		struct Qdisc *q = tcf_block_q(tp->chain->block);
88 
89 		/* Old method: classify the packet using its skb mark. */
90 		if (id && (TC_H_MAJ(id) == 0 ||
91 			   !(TC_H_MAJ(id ^ q->handle)))) {
92 			res->classid = id;
93 			res->class = 0;
94 			return 0;
95 		}
96 	}
97 
98 	return -1;
99 }
100 
101 static void *fw_get(struct tcf_proto *tp, u32 handle)
102 {
103 	struct fw_head *head = rtnl_dereference(tp->root);
104 	struct fw_filter *f;
105 
106 	if (head == NULL)
107 		return NULL;
108 
109 	f = rtnl_dereference(head->ht[fw_hash(handle)]);
110 	for (; f; f = rtnl_dereference(f->next)) {
111 		if (f->id == handle)
112 			return f;
113 	}
114 	return NULL;
115 }
116 
117 static int fw_init(struct tcf_proto *tp)
118 {
119 	/* We don't allocate fw_head here, because in the old method
120 	 * we don't need it at all.
121 	 */
122 	return 0;
123 }
124 
125 static void __fw_delete_filter(struct fw_filter *f)
126 {
127 	tcf_exts_destroy(&f->exts);
128 	tcf_exts_put_net(&f->exts);
129 	kfree(f);
130 }
131 
132 static void fw_delete_filter_work(struct work_struct *work)
133 {
134 	struct fw_filter *f = container_of(to_rcu_work(work),
135 					   struct fw_filter,
136 					   rwork);
137 	rtnl_lock();
138 	__fw_delete_filter(f);
139 	rtnl_unlock();
140 }
141 
142 static void fw_destroy(struct tcf_proto *tp, bool rtnl_held,
143 		       struct netlink_ext_ack *extack)
144 {
145 	struct fw_head *head = rtnl_dereference(tp->root);
146 	struct fw_filter *f;
147 	int h;
148 
149 	if (head == NULL)
150 		return;
151 
152 	for (h = 0; h < HTSIZE; h++) {
153 		while ((f = rtnl_dereference(head->ht[h])) != NULL) {
154 			RCU_INIT_POINTER(head->ht[h],
155 					 rtnl_dereference(f->next));
156 			tcf_unbind_filter(tp, &f->res);
157 			if (tcf_exts_get_net(&f->exts))
158 				tcf_queue_work(&f->rwork, fw_delete_filter_work);
159 			else
160 				__fw_delete_filter(f);
161 		}
162 	}
163 	kfree_rcu(head, rcu);
164 }
165 
166 static int fw_delete(struct tcf_proto *tp, void *arg, bool *last,
167 		     bool rtnl_held, struct netlink_ext_ack *extack)
168 {
169 	struct fw_head *head = rtnl_dereference(tp->root);
170 	struct fw_filter *f = arg;
171 	struct fw_filter __rcu **fp;
172 	struct fw_filter *pfp;
173 	int ret = -EINVAL;
174 	int h;
175 
176 	if (head == NULL || f == NULL)
177 		goto out;
178 
179 	fp = &head->ht[fw_hash(f->id)];
180 
181 	for (pfp = rtnl_dereference(*fp); pfp;
182 	     fp = &pfp->next, pfp = rtnl_dereference(*fp)) {
183 		if (pfp == f) {
184 			RCU_INIT_POINTER(*fp, rtnl_dereference(f->next));
185 			tcf_unbind_filter(tp, &f->res);
186 			tcf_exts_get_net(&f->exts);
187 			tcf_queue_work(&f->rwork, fw_delete_filter_work);
188 			ret = 0;
189 			break;
190 		}
191 	}
192 
193 	*last = true;
194 	for (h = 0; h < HTSIZE; h++) {
195 		if (rcu_access_pointer(head->ht[h])) {
196 			*last = false;
197 			break;
198 		}
199 	}
200 
201 out:
202 	return ret;
203 }
204 
205 static const struct nla_policy fw_policy[TCA_FW_MAX + 1] = {
206 	[TCA_FW_CLASSID]	= { .type = NLA_U32 },
207 	[TCA_FW_INDEV]		= { .type = NLA_STRING, .len = IFNAMSIZ },
208 	[TCA_FW_MASK]		= { .type = NLA_U32 },
209 };
210 
211 static int fw_set_parms(struct net *net, struct tcf_proto *tp,
212 			struct fw_filter *f, struct nlattr **tb,
213 			struct nlattr **tca, unsigned long base, bool ovr,
214 			struct netlink_ext_ack *extack)
215 {
216 	struct fw_head *head = rtnl_dereference(tp->root);
217 	u32 mask;
218 	int err;
219 
220 	err = tcf_exts_validate(net, tp, tb, tca[TCA_RATE], &f->exts, ovr,
221 				true, extack);
222 	if (err < 0)
223 		return err;
224 
225 	if (tb[TCA_FW_CLASSID]) {
226 		f->res.classid = nla_get_u32(tb[TCA_FW_CLASSID]);
227 		tcf_bind_filter(tp, &f->res, base);
228 	}
229 
230 #ifdef CONFIG_NET_CLS_IND
231 	if (tb[TCA_FW_INDEV]) {
232 		int ret;
233 		ret = tcf_change_indev(net, tb[TCA_FW_INDEV], extack);
234 		if (ret < 0)
235 			return ret;
236 		f->ifindex = ret;
237 	}
238 #endif /* CONFIG_NET_CLS_IND */
239 
240 	err = -EINVAL;
241 	if (tb[TCA_FW_MASK]) {
242 		mask = nla_get_u32(tb[TCA_FW_MASK]);
243 		if (mask != head->mask)
244 			return err;
245 	} else if (head->mask != 0xFFFFFFFF)
246 		return err;
247 
248 	return 0;
249 }
250 
251 static int fw_change(struct net *net, struct sk_buff *in_skb,
252 		     struct tcf_proto *tp, unsigned long base,
253 		     u32 handle, struct nlattr **tca, void **arg,
254 		     bool ovr, bool rtnl_held,
255 		     struct netlink_ext_ack *extack)
256 {
257 	struct fw_head *head = rtnl_dereference(tp->root);
258 	struct fw_filter *f = *arg;
259 	struct nlattr *opt = tca[TCA_OPTIONS];
260 	struct nlattr *tb[TCA_FW_MAX + 1];
261 	int err;
262 
263 	if (!opt)
264 		return handle ? -EINVAL : 0; /* Succeed if it is old method. */
265 
266 	err = nla_parse_nested(tb, TCA_FW_MAX, opt, fw_policy, NULL);
267 	if (err < 0)
268 		return err;
269 
270 	if (f) {
271 		struct fw_filter *pfp, *fnew;
272 		struct fw_filter __rcu **fp;
273 
274 		if (f->id != handle && handle)
275 			return -EINVAL;
276 
277 		fnew = kzalloc(sizeof(struct fw_filter), GFP_KERNEL);
278 		if (!fnew)
279 			return -ENOBUFS;
280 
281 		fnew->id = f->id;
282 		fnew->res = f->res;
283 #ifdef CONFIG_NET_CLS_IND
284 		fnew->ifindex = f->ifindex;
285 #endif /* CONFIG_NET_CLS_IND */
286 		fnew->tp = f->tp;
287 
288 		err = tcf_exts_init(&fnew->exts, net, TCA_FW_ACT,
289 				    TCA_FW_POLICE);
290 		if (err < 0) {
291 			kfree(fnew);
292 			return err;
293 		}
294 
295 		err = fw_set_parms(net, tp, fnew, tb, tca, base, ovr, extack);
296 		if (err < 0) {
297 			tcf_exts_destroy(&fnew->exts);
298 			kfree(fnew);
299 			return err;
300 		}
301 
302 		fp = &head->ht[fw_hash(fnew->id)];
303 		for (pfp = rtnl_dereference(*fp); pfp;
304 		     fp = &pfp->next, pfp = rtnl_dereference(*fp))
305 			if (pfp == f)
306 				break;
307 
308 		RCU_INIT_POINTER(fnew->next, rtnl_dereference(pfp->next));
309 		rcu_assign_pointer(*fp, fnew);
310 		tcf_unbind_filter(tp, &f->res);
311 		tcf_exts_get_net(&f->exts);
312 		tcf_queue_work(&f->rwork, fw_delete_filter_work);
313 
314 		*arg = fnew;
315 		return err;
316 	}
317 
318 	if (!handle)
319 		return -EINVAL;
320 
321 	if (!head) {
322 		u32 mask = 0xFFFFFFFF;
323 		if (tb[TCA_FW_MASK])
324 			mask = nla_get_u32(tb[TCA_FW_MASK]);
325 
326 		head = kzalloc(sizeof(*head), GFP_KERNEL);
327 		if (!head)
328 			return -ENOBUFS;
329 		head->mask = mask;
330 
331 		rcu_assign_pointer(tp->root, head);
332 	}
333 
334 	f = kzalloc(sizeof(struct fw_filter), GFP_KERNEL);
335 	if (f == NULL)
336 		return -ENOBUFS;
337 
338 	err = tcf_exts_init(&f->exts, net, TCA_FW_ACT, TCA_FW_POLICE);
339 	if (err < 0)
340 		goto errout;
341 	f->id = handle;
342 	f->tp = tp;
343 
344 	err = fw_set_parms(net, tp, f, tb, tca, base, ovr, extack);
345 	if (err < 0)
346 		goto errout;
347 
348 	RCU_INIT_POINTER(f->next, head->ht[fw_hash(handle)]);
349 	rcu_assign_pointer(head->ht[fw_hash(handle)], f);
350 
351 	*arg = f;
352 	return 0;
353 
354 errout:
355 	tcf_exts_destroy(&f->exts);
356 	kfree(f);
357 	return err;
358 }
359 
360 static void fw_walk(struct tcf_proto *tp, struct tcf_walker *arg,
361 		    bool rtnl_held)
362 {
363 	struct fw_head *head = rtnl_dereference(tp->root);
364 	int h;
365 
366 	if (head == NULL)
367 		arg->stop = 1;
368 
369 	if (arg->stop)
370 		return;
371 
372 	for (h = 0; h < HTSIZE; h++) {
373 		struct fw_filter *f;
374 
375 		for (f = rtnl_dereference(head->ht[h]); f;
376 		     f = rtnl_dereference(f->next)) {
377 			if (arg->count < arg->skip) {
378 				arg->count++;
379 				continue;
380 			}
381 			if (arg->fn(tp, f, arg) < 0) {
382 				arg->stop = 1;
383 				return;
384 			}
385 			arg->count++;
386 		}
387 	}
388 }
389 
390 static int fw_dump(struct net *net, struct tcf_proto *tp, void *fh,
391 		   struct sk_buff *skb, struct tcmsg *t, bool rtnl_held)
392 {
393 	struct fw_head *head = rtnl_dereference(tp->root);
394 	struct fw_filter *f = fh;
395 	struct nlattr *nest;
396 
397 	if (f == NULL)
398 		return skb->len;
399 
400 	t->tcm_handle = f->id;
401 
402 	if (!f->res.classid && !tcf_exts_has_actions(&f->exts))
403 		return skb->len;
404 
405 	nest = nla_nest_start(skb, TCA_OPTIONS);
406 	if (nest == NULL)
407 		goto nla_put_failure;
408 
409 	if (f->res.classid &&
410 	    nla_put_u32(skb, TCA_FW_CLASSID, f->res.classid))
411 		goto nla_put_failure;
412 #ifdef CONFIG_NET_CLS_IND
413 	if (f->ifindex) {
414 		struct net_device *dev;
415 		dev = __dev_get_by_index(net, f->ifindex);
416 		if (dev && nla_put_string(skb, TCA_FW_INDEV, dev->name))
417 			goto nla_put_failure;
418 	}
419 #endif /* CONFIG_NET_CLS_IND */
420 	if (head->mask != 0xFFFFFFFF &&
421 	    nla_put_u32(skb, TCA_FW_MASK, head->mask))
422 		goto nla_put_failure;
423 
424 	if (tcf_exts_dump(skb, &f->exts) < 0)
425 		goto nla_put_failure;
426 
427 	nla_nest_end(skb, nest);
428 
429 	if (tcf_exts_dump_stats(skb, &f->exts) < 0)
430 		goto nla_put_failure;
431 
432 	return skb->len;
433 
434 nla_put_failure:
435 	nla_nest_cancel(skb, nest);
436 	return -1;
437 }
438 
439 static void fw_bind_class(void *fh, u32 classid, unsigned long cl)
440 {
441 	struct fw_filter *f = fh;
442 
443 	if (f && f->res.classid == classid)
444 		f->res.class = cl;
445 }
446 
447 static struct tcf_proto_ops cls_fw_ops __read_mostly = {
448 	.kind		=	"fw",
449 	.classify	=	fw_classify,
450 	.init		=	fw_init,
451 	.destroy	=	fw_destroy,
452 	.get		=	fw_get,
453 	.change		=	fw_change,
454 	.delete		=	fw_delete,
455 	.walk		=	fw_walk,
456 	.dump		=	fw_dump,
457 	.bind_class	=	fw_bind_class,
458 	.owner		=	THIS_MODULE,
459 };
460 
461 static int __init init_fw(void)
462 {
463 	return register_tcf_proto_ops(&cls_fw_ops);
464 }
465 
466 static void __exit exit_fw(void)
467 {
468 	unregister_tcf_proto_ops(&cls_fw_ops);
469 }
470 
471 module_init(init_fw)
472 module_exit(exit_fw)
473 MODULE_LICENSE("GPL");
474