xref: /linux/net/sched/cls_fw.c (revision 33dea5aae0320345af26ae9aba0894a930e0d4ec) 
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 
32 #define HTSIZE 256
33 
34 struct fw_head {
35 	u32			mask;
36 	struct fw_filter __rcu	*ht[HTSIZE];
37 	struct rcu_head		rcu;
38 };
39 
40 struct fw_filter {
41 	struct fw_filter __rcu	*next;
42 	u32			id;
43 	struct tcf_result	res;
44 #ifdef CONFIG_NET_CLS_IND
45 	int			ifindex;
46 #endif /* CONFIG_NET_CLS_IND */
47 	struct tcf_exts		exts;
48 	struct tcf_proto	*tp;
49 	union {
50 		struct work_struct	work;
51 		struct rcu_head		rcu;
52 	};
53 };
54 
55 static u32 fw_hash(u32 handle)
56 {
57 	handle ^= (handle >> 16);
58 	handle ^= (handle >> 8);
59 	return handle % HTSIZE;
60 }
61 
62 static int fw_classify(struct sk_buff *skb, const struct tcf_proto *tp,
63 		       struct tcf_result *res)
64 {
65 	struct fw_head *head = rcu_dereference_bh(tp->root);
66 	struct fw_filter *f;
67 	int r;
68 	u32 id = skb->mark;
69 
70 	if (head != NULL) {
71 		id &= head->mask;
72 
73 		for (f = rcu_dereference_bh(head->ht[fw_hash(id)]); f;
74 		     f = rcu_dereference_bh(f->next)) {
75 			if (f->id == id) {
76 				*res = f->res;
77 #ifdef CONFIG_NET_CLS_IND
78 				if (!tcf_match_indev(skb, f->ifindex))
79 					continue;
80 #endif /* CONFIG_NET_CLS_IND */
81 				r = tcf_exts_exec(skb, &f->exts, res);
82 				if (r < 0)
83 					continue;
84 
85 				return r;
86 			}
87 		}
88 	} else {
89 		/* Old method: classify the packet using its skb mark. */
90 		if (id && (TC_H_MAJ(id) == 0 ||
91 			   !(TC_H_MAJ(id ^ tp->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(work, struct fw_filter, work);
135 
136 	rtnl_lock();
137 	__fw_delete_filter(f);
138 	rtnl_unlock();
139 }
140 
141 static void fw_delete_filter(struct rcu_head *head)
142 {
143 	struct fw_filter *f = container_of(head, struct fw_filter, rcu);
144 
145 	INIT_WORK(&f->work, fw_delete_filter_work);
146 	tcf_queue_work(&f->work);
147 }
148 
149 static void fw_destroy(struct tcf_proto *tp)
150 {
151 	struct fw_head *head = rtnl_dereference(tp->root);
152 	struct fw_filter *f;
153 	int h;
154 
155 	if (head == NULL)
156 		return;
157 
158 	for (h = 0; h < HTSIZE; h++) {
159 		while ((f = rtnl_dereference(head->ht[h])) != NULL) {
160 			RCU_INIT_POINTER(head->ht[h],
161 					 rtnl_dereference(f->next));
162 			tcf_unbind_filter(tp, &f->res);
163 			if (tcf_exts_get_net(&f->exts))
164 				call_rcu(&f->rcu, fw_delete_filter);
165 			else
166 				__fw_delete_filter(f);
167 		}
168 	}
169 	kfree_rcu(head, rcu);
170 }
171 
172 static int fw_delete(struct tcf_proto *tp, void *arg, bool *last)
173 {
174 	struct fw_head *head = rtnl_dereference(tp->root);
175 	struct fw_filter *f = arg;
176 	struct fw_filter __rcu **fp;
177 	struct fw_filter *pfp;
178 	int ret = -EINVAL;
179 	int h;
180 
181 	if (head == NULL || f == NULL)
182 		goto out;
183 
184 	fp = &head->ht[fw_hash(f->id)];
185 
186 	for (pfp = rtnl_dereference(*fp); pfp;
187 	     fp = &pfp->next, pfp = rtnl_dereference(*fp)) {
188 		if (pfp == f) {
189 			RCU_INIT_POINTER(*fp, rtnl_dereference(f->next));
190 			tcf_unbind_filter(tp, &f->res);
191 			tcf_exts_get_net(&f->exts);
192 			call_rcu(&f->rcu, fw_delete_filter);
193 			ret = 0;
194 			break;
195 		}
196 	}
197 
198 	*last = true;
199 	for (h = 0; h < HTSIZE; h++) {
200 		if (rcu_access_pointer(head->ht[h])) {
201 			*last = false;
202 			break;
203 		}
204 	}
205 
206 out:
207 	return ret;
208 }
209 
210 static const struct nla_policy fw_policy[TCA_FW_MAX + 1] = {
211 	[TCA_FW_CLASSID]	= { .type = NLA_U32 },
212 	[TCA_FW_INDEV]		= { .type = NLA_STRING, .len = IFNAMSIZ },
213 	[TCA_FW_MASK]		= { .type = NLA_U32 },
214 };
215 
216 static int fw_set_parms(struct net *net, struct tcf_proto *tp,
217 			struct fw_filter *f, struct nlattr **tb,
218 			struct nlattr **tca, unsigned long base, bool ovr)
219 {
220 	struct fw_head *head = rtnl_dereference(tp->root);
221 	u32 mask;
222 	int err;
223 
224 	err = tcf_exts_validate(net, tp, tb, tca[TCA_RATE], &f->exts, ovr);
225 	if (err < 0)
226 		return err;
227 
228 	if (tb[TCA_FW_CLASSID]) {
229 		f->res.classid = nla_get_u32(tb[TCA_FW_CLASSID]);
230 		tcf_bind_filter(tp, &f->res, base);
231 	}
232 
233 #ifdef CONFIG_NET_CLS_IND
234 	if (tb[TCA_FW_INDEV]) {
235 		int ret;
236 		ret = tcf_change_indev(net, tb[TCA_FW_INDEV]);
237 		if (ret < 0)
238 			return ret;
239 		f->ifindex = ret;
240 	}
241 #endif /* CONFIG_NET_CLS_IND */
242 
243 	err = -EINVAL;
244 	if (tb[TCA_FW_MASK]) {
245 		mask = nla_get_u32(tb[TCA_FW_MASK]);
246 		if (mask != head->mask)
247 			return err;
248 	} else if (head->mask != 0xFFFFFFFF)
249 		return err;
250 
251 	return 0;
252 }
253 
254 static int fw_change(struct net *net, struct sk_buff *in_skb,
255 		     struct tcf_proto *tp, unsigned long base,
256 		     u32 handle, struct nlattr **tca, void **arg,
257 		     bool ovr)
258 {
259 	struct fw_head *head = rtnl_dereference(tp->root);
260 	struct fw_filter *f = *arg;
261 	struct nlattr *opt = tca[TCA_OPTIONS];
262 	struct nlattr *tb[TCA_FW_MAX + 1];
263 	int err;
264 
265 	if (!opt)
266 		return handle ? -EINVAL : 0; /* Succeed if it is old method. */
267 
268 	err = nla_parse_nested(tb, TCA_FW_MAX, opt, fw_policy, NULL);
269 	if (err < 0)
270 		return err;
271 
272 	if (f) {
273 		struct fw_filter *pfp, *fnew;
274 		struct fw_filter __rcu **fp;
275 
276 		if (f->id != handle && handle)
277 			return -EINVAL;
278 
279 		fnew = kzalloc(sizeof(struct fw_filter), GFP_KERNEL);
280 		if (!fnew)
281 			return -ENOBUFS;
282 
283 		fnew->id = f->id;
284 		fnew->res = f->res;
285 #ifdef CONFIG_NET_CLS_IND
286 		fnew->ifindex = f->ifindex;
287 #endif /* CONFIG_NET_CLS_IND */
288 		fnew->tp = f->tp;
289 
290 		err = tcf_exts_init(&fnew->exts, TCA_FW_ACT, TCA_FW_POLICE);
291 		if (err < 0) {
292 			kfree(fnew);
293 			return err;
294 		}
295 
296 		err = fw_set_parms(net, tp, fnew, tb, tca, base, ovr);
297 		if (err < 0) {
298 			tcf_exts_destroy(&fnew->exts);
299 			kfree(fnew);
300 			return err;
301 		}
302 
303 		fp = &head->ht[fw_hash(fnew->id)];
304 		for (pfp = rtnl_dereference(*fp); pfp;
305 		     fp = &pfp->next, pfp = rtnl_dereference(*fp))
306 			if (pfp == f)
307 				break;
308 
309 		RCU_INIT_POINTER(fnew->next, rtnl_dereference(pfp->next));
310 		rcu_assign_pointer(*fp, fnew);
311 		tcf_unbind_filter(tp, &f->res);
312 		tcf_exts_get_net(&f->exts);
313 		call_rcu(&f->rcu, fw_delete_filter);
314 
315 		*arg = fnew;
316 		return err;
317 	}
318 
319 	if (!handle)
320 		return -EINVAL;
321 
322 	if (!head) {
323 		u32 mask = 0xFFFFFFFF;
324 		if (tb[TCA_FW_MASK])
325 			mask = nla_get_u32(tb[TCA_FW_MASK]);
326 
327 		head = kzalloc(sizeof(*head), GFP_KERNEL);
328 		if (!head)
329 			return -ENOBUFS;
330 		head->mask = mask;
331 
332 		rcu_assign_pointer(tp->root, head);
333 	}
334 
335 	f = kzalloc(sizeof(struct fw_filter), GFP_KERNEL);
336 	if (f == NULL)
337 		return -ENOBUFS;
338 
339 	err = tcf_exts_init(&f->exts, TCA_FW_ACT, TCA_FW_POLICE);
340 	if (err < 0)
341 		goto errout;
342 	f->id = handle;
343 	f->tp = tp;
344 
345 	err = fw_set_parms(net, tp, f, tb, tca, base, ovr);
346 	if (err < 0)
347 		goto errout;
348 
349 	RCU_INIT_POINTER(f->next, head->ht[fw_hash(handle)]);
350 	rcu_assign_pointer(head->ht[fw_hash(handle)], f);
351 
352 	*arg = f;
353 	return 0;
354 
355 errout:
356 	tcf_exts_destroy(&f->exts);
357 	kfree(f);
358 	return err;
359 }
360 
361 static void fw_walk(struct tcf_proto *tp, struct tcf_walker *arg)
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)
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