xref: /linux/net/sched/cls_fw.c (revision b2d0f5d5dc53532e6f07bc546a476a55ebdfe0f3) 
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 	union {
51 		struct work_struct	work;
52 		struct rcu_head		rcu;
53 	};
54 };
55 
56 static u32 fw_hash(u32 handle)
57 {
58 	handle ^= (handle >> 16);
59 	handle ^= (handle >> 8);
60 	return handle % HTSIZE;
61 }
62 
63 static int fw_classify(struct sk_buff *skb, const struct tcf_proto *tp,
64 		       struct tcf_result *res)
65 {
66 	struct fw_head *head = rcu_dereference_bh(tp->root);
67 	struct fw_filter *f;
68 	int r;
69 	u32 id = skb->mark;
70 
71 	if (head != NULL) {
72 		id &= head->mask;
73 
74 		for (f = rcu_dereference_bh(head->ht[fw_hash(id)]); f;
75 		     f = rcu_dereference_bh(f->next)) {
76 			if (f->id == id) {
77 				*res = f->res;
78 #ifdef CONFIG_NET_CLS_IND
79 				if (!tcf_match_indev(skb, f->ifindex))
80 					continue;
81 #endif /* CONFIG_NET_CLS_IND */
82 				r = tcf_exts_exec(skb, &f->exts, res);
83 				if (r < 0)
84 					continue;
85 
86 				return r;
87 			}
88 		}
89 	} else {
90 		struct Qdisc *q = tcf_block_q(tp->chain->block);
91 
92 		/* Old method: classify the packet using its skb mark. */
93 		if (id && (TC_H_MAJ(id) == 0 ||
94 			   !(TC_H_MAJ(id ^ q->handle)))) {
95 			res->classid = id;
96 			res->class = 0;
97 			return 0;
98 		}
99 	}
100 
101 	return -1;
102 }
103 
104 static void *fw_get(struct tcf_proto *tp, u32 handle)
105 {
106 	struct fw_head *head = rtnl_dereference(tp->root);
107 	struct fw_filter *f;
108 
109 	if (head == NULL)
110 		return NULL;
111 
112 	f = rtnl_dereference(head->ht[fw_hash(handle)]);
113 	for (; f; f = rtnl_dereference(f->next)) {
114 		if (f->id == handle)
115 			return f;
116 	}
117 	return NULL;
118 }
119 
120 static int fw_init(struct tcf_proto *tp)
121 {
122 	/* We don't allocate fw_head here, because in the old method
123 	 * we don't need it at all.
124 	 */
125 	return 0;
126 }
127 
128 static void fw_delete_filter_work(struct work_struct *work)
129 {
130 	struct fw_filter *f = container_of(work, struct fw_filter, work);
131 
132 	rtnl_lock();
133 	tcf_exts_destroy(&f->exts);
134 	kfree(f);
135 	rtnl_unlock();
136 }
137 
138 static void fw_delete_filter(struct rcu_head *head)
139 {
140 	struct fw_filter *f = container_of(head, struct fw_filter, rcu);
141 
142 	INIT_WORK(&f->work, fw_delete_filter_work);
143 	tcf_queue_work(&f->work);
144 }
145 
146 static void fw_destroy(struct tcf_proto *tp)
147 {
148 	struct fw_head *head = rtnl_dereference(tp->root);
149 	struct fw_filter *f;
150 	int h;
151 
152 	if (head == NULL)
153 		return;
154 
155 	for (h = 0; h < HTSIZE; h++) {
156 		while ((f = rtnl_dereference(head->ht[h])) != NULL) {
157 			RCU_INIT_POINTER(head->ht[h],
158 					 rtnl_dereference(f->next));
159 			tcf_unbind_filter(tp, &f->res);
160 			call_rcu(&f->rcu, fw_delete_filter);
161 		}
162 	}
163 	kfree_rcu(head, rcu);
164 }
165 
166 static int fw_delete(struct tcf_proto *tp, void *arg, bool *last)
167 {
168 	struct fw_head *head = rtnl_dereference(tp->root);
169 	struct fw_filter *f = arg;
170 	struct fw_filter __rcu **fp;
171 	struct fw_filter *pfp;
172 	int ret = -EINVAL;
173 	int h;
174 
175 	if (head == NULL || f == NULL)
176 		goto out;
177 
178 	fp = &head->ht[fw_hash(f->id)];
179 
180 	for (pfp = rtnl_dereference(*fp); pfp;
181 	     fp = &pfp->next, pfp = rtnl_dereference(*fp)) {
182 		if (pfp == f) {
183 			RCU_INIT_POINTER(*fp, rtnl_dereference(f->next));
184 			tcf_unbind_filter(tp, &f->res);
185 			call_rcu(&f->rcu, fw_delete_filter);
186 			ret = 0;
187 			break;
188 		}
189 	}
190 
191 	*last = true;
192 	for (h = 0; h < HTSIZE; h++) {
193 		if (rcu_access_pointer(head->ht[h])) {
194 			*last = false;
195 			break;
196 		}
197 	}
198 
199 out:
200 	return ret;
201 }
202 
203 static const struct nla_policy fw_policy[TCA_FW_MAX + 1] = {
204 	[TCA_FW_CLASSID]	= { .type = NLA_U32 },
205 	[TCA_FW_INDEV]		= { .type = NLA_STRING, .len = IFNAMSIZ },
206 	[TCA_FW_MASK]		= { .type = NLA_U32 },
207 };
208 
209 static int fw_set_parms(struct net *net, struct tcf_proto *tp,
210 			struct fw_filter *f, struct nlattr **tb,
211 			struct nlattr **tca, unsigned long base, bool ovr)
212 {
213 	struct fw_head *head = rtnl_dereference(tp->root);
214 	u32 mask;
215 	int err;
216 
217 	err = tcf_exts_validate(net, tp, tb, tca[TCA_RATE], &f->exts, ovr);
218 	if (err < 0)
219 		return err;
220 
221 	if (tb[TCA_FW_CLASSID]) {
222 		f->res.classid = nla_get_u32(tb[TCA_FW_CLASSID]);
223 		tcf_bind_filter(tp, &f->res, base);
224 	}
225 
226 #ifdef CONFIG_NET_CLS_IND
227 	if (tb[TCA_FW_INDEV]) {
228 		int ret;
229 		ret = tcf_change_indev(net, tb[TCA_FW_INDEV]);
230 		if (ret < 0)
231 			return ret;
232 		f->ifindex = ret;
233 	}
234 #endif /* CONFIG_NET_CLS_IND */
235 
236 	err = -EINVAL;
237 	if (tb[TCA_FW_MASK]) {
238 		mask = nla_get_u32(tb[TCA_FW_MASK]);
239 		if (mask != head->mask)
240 			return err;
241 	} else if (head->mask != 0xFFFFFFFF)
242 		return err;
243 
244 	return 0;
245 }
246 
247 static int fw_change(struct net *net, struct sk_buff *in_skb,
248 		     struct tcf_proto *tp, unsigned long base,
249 		     u32 handle, struct nlattr **tca, void **arg,
250 		     bool ovr)
251 {
252 	struct fw_head *head = rtnl_dereference(tp->root);
253 	struct fw_filter *f = *arg;
254 	struct nlattr *opt = tca[TCA_OPTIONS];
255 	struct nlattr *tb[TCA_FW_MAX + 1];
256 	int err;
257 
258 	if (!opt)
259 		return handle ? -EINVAL : 0; /* Succeed if it is old method. */
260 
261 	err = nla_parse_nested(tb, TCA_FW_MAX, opt, fw_policy, NULL);
262 	if (err < 0)
263 		return err;
264 
265 	if (f) {
266 		struct fw_filter *pfp, *fnew;
267 		struct fw_filter __rcu **fp;
268 
269 		if (f->id != handle && handle)
270 			return -EINVAL;
271 
272 		fnew = kzalloc(sizeof(struct fw_filter), GFP_KERNEL);
273 		if (!fnew)
274 			return -ENOBUFS;
275 
276 		fnew->id = f->id;
277 		fnew->res = f->res;
278 #ifdef CONFIG_NET_CLS_IND
279 		fnew->ifindex = f->ifindex;
280 #endif /* CONFIG_NET_CLS_IND */
281 		fnew->tp = f->tp;
282 
283 		err = tcf_exts_init(&fnew->exts, TCA_FW_ACT, TCA_FW_POLICE);
284 		if (err < 0) {
285 			kfree(fnew);
286 			return err;
287 		}
288 
289 		err = fw_set_parms(net, tp, fnew, tb, tca, base, ovr);
290 		if (err < 0) {
291 			tcf_exts_destroy(&fnew->exts);
292 			kfree(fnew);
293 			return err;
294 		}
295 
296 		fp = &head->ht[fw_hash(fnew->id)];
297 		for (pfp = rtnl_dereference(*fp); pfp;
298 		     fp = &pfp->next, pfp = rtnl_dereference(*fp))
299 			if (pfp == f)
300 				break;
301 
302 		RCU_INIT_POINTER(fnew->next, rtnl_dereference(pfp->next));
303 		rcu_assign_pointer(*fp, fnew);
304 		tcf_unbind_filter(tp, &f->res);
305 		call_rcu(&f->rcu, fw_delete_filter);
306 
307 		*arg = fnew;
308 		return err;
309 	}
310 
311 	if (!handle)
312 		return -EINVAL;
313 
314 	if (!head) {
315 		u32 mask = 0xFFFFFFFF;
316 		if (tb[TCA_FW_MASK])
317 			mask = nla_get_u32(tb[TCA_FW_MASK]);
318 
319 		head = kzalloc(sizeof(*head), GFP_KERNEL);
320 		if (!head)
321 			return -ENOBUFS;
322 		head->mask = mask;
323 
324 		rcu_assign_pointer(tp->root, head);
325 	}
326 
327 	f = kzalloc(sizeof(struct fw_filter), GFP_KERNEL);
328 	if (f == NULL)
329 		return -ENOBUFS;
330 
331 	err = tcf_exts_init(&f->exts, TCA_FW_ACT, TCA_FW_POLICE);
332 	if (err < 0)
333 		goto errout;
334 	f->id = handle;
335 	f->tp = tp;
336 
337 	err = fw_set_parms(net, tp, f, tb, tca, base, ovr);
338 	if (err < 0)
339 		goto errout;
340 
341 	RCU_INIT_POINTER(f->next, head->ht[fw_hash(handle)]);
342 	rcu_assign_pointer(head->ht[fw_hash(handle)], f);
343 
344 	*arg = f;
345 	return 0;
346 
347 errout:
348 	tcf_exts_destroy(&f->exts);
349 	kfree(f);
350 	return err;
351 }
352 
353 static void fw_walk(struct tcf_proto *tp, struct tcf_walker *arg)
354 {
355 	struct fw_head *head = rtnl_dereference(tp->root);
356 	int h;
357 
358 	if (head == NULL)
359 		arg->stop = 1;
360 
361 	if (arg->stop)
362 		return;
363 
364 	for (h = 0; h < HTSIZE; h++) {
365 		struct fw_filter *f;
366 
367 		for (f = rtnl_dereference(head->ht[h]); f;
368 		     f = rtnl_dereference(f->next)) {
369 			if (arg->count < arg->skip) {
370 				arg->count++;
371 				continue;
372 			}
373 			if (arg->fn(tp, f, arg) < 0) {
374 				arg->stop = 1;
375 				return;
376 			}
377 			arg->count++;
378 		}
379 	}
380 }
381 
382 static int fw_dump(struct net *net, struct tcf_proto *tp, void *fh,
383 		   struct sk_buff *skb, struct tcmsg *t)
384 {
385 	struct fw_head *head = rtnl_dereference(tp->root);
386 	struct fw_filter *f = fh;
387 	struct nlattr *nest;
388 
389 	if (f == NULL)
390 		return skb->len;
391 
392 	t->tcm_handle = f->id;
393 
394 	if (!f->res.classid && !tcf_exts_has_actions(&f->exts))
395 		return skb->len;
396 
397 	nest = nla_nest_start(skb, TCA_OPTIONS);
398 	if (nest == NULL)
399 		goto nla_put_failure;
400 
401 	if (f->res.classid &&
402 	    nla_put_u32(skb, TCA_FW_CLASSID, f->res.classid))
403 		goto nla_put_failure;
404 #ifdef CONFIG_NET_CLS_IND
405 	if (f->ifindex) {
406 		struct net_device *dev;
407 		dev = __dev_get_by_index(net, f->ifindex);
408 		if (dev && nla_put_string(skb, TCA_FW_INDEV, dev->name))
409 			goto nla_put_failure;
410 	}
411 #endif /* CONFIG_NET_CLS_IND */
412 	if (head->mask != 0xFFFFFFFF &&
413 	    nla_put_u32(skb, TCA_FW_MASK, head->mask))
414 		goto nla_put_failure;
415 
416 	if (tcf_exts_dump(skb, &f->exts) < 0)
417 		goto nla_put_failure;
418 
419 	nla_nest_end(skb, nest);
420 
421 	if (tcf_exts_dump_stats(skb, &f->exts) < 0)
422 		goto nla_put_failure;
423 
424 	return skb->len;
425 
426 nla_put_failure:
427 	nla_nest_cancel(skb, nest);
428 	return -1;
429 }
430 
431 static void fw_bind_class(void *fh, u32 classid, unsigned long cl)
432 {
433 	struct fw_filter *f = fh;
434 
435 	if (f && f->res.classid == classid)
436 		f->res.class = cl;
437 }
438 
439 static struct tcf_proto_ops cls_fw_ops __read_mostly = {
440 	.kind		=	"fw",
441 	.classify	=	fw_classify,
442 	.init		=	fw_init,
443 	.destroy	=	fw_destroy,
444 	.get		=	fw_get,
445 	.change		=	fw_change,
446 	.delete		=	fw_delete,
447 	.walk		=	fw_walk,
448 	.dump		=	fw_dump,
449 	.bind_class	=	fw_bind_class,
450 	.owner		=	THIS_MODULE,
451 };
452 
453 static int __init init_fw(void)
454 {
455 	return register_tcf_proto_ops(&cls_fw_ops);
456 }
457 
458 static void __exit exit_fw(void)
459 {
460 	unregister_tcf_proto_ops(&cls_fw_ops);
461 }
462 
463 module_init(init_fw)
464 module_exit(exit_fw)
465 MODULE_LICENSE("GPL");
466