xref: /openbmc/linux/net/sched/cls_fw.c (revision 4cff79e9) 
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(struct fw_filter *f)
129 {
130 	tcf_exts_destroy(&f->exts);
131 	tcf_exts_put_net(&f->exts);
132 	kfree(f);
133 }
134 
135 static void fw_delete_filter_work(struct work_struct *work)
136 {
137 	struct fw_filter *f = container_of(work, struct fw_filter, work);
138 
139 	rtnl_lock();
140 	__fw_delete_filter(f);
141 	rtnl_unlock();
142 }
143 
144 static void fw_delete_filter(struct rcu_head *head)
145 {
146 	struct fw_filter *f = container_of(head, struct fw_filter, rcu);
147 
148 	INIT_WORK(&f->work, fw_delete_filter_work);
149 	tcf_queue_work(&f->work);
150 }
151 
152 static void fw_destroy(struct tcf_proto *tp, struct netlink_ext_ack *extack)
153 {
154 	struct fw_head *head = rtnl_dereference(tp->root);
155 	struct fw_filter *f;
156 	int h;
157 
158 	if (head == NULL)
159 		return;
160 
161 	for (h = 0; h < HTSIZE; h++) {
162 		while ((f = rtnl_dereference(head->ht[h])) != NULL) {
163 			RCU_INIT_POINTER(head->ht[h],
164 					 rtnl_dereference(f->next));
165 			tcf_unbind_filter(tp, &f->res);
166 			if (tcf_exts_get_net(&f->exts))
167 				call_rcu(&f->rcu, fw_delete_filter);
168 			else
169 				__fw_delete_filter(f);
170 		}
171 	}
172 	kfree_rcu(head, rcu);
173 }
174 
175 static int fw_delete(struct tcf_proto *tp, void *arg, bool *last,
176 		     struct netlink_ext_ack *extack)
177 {
178 	struct fw_head *head = rtnl_dereference(tp->root);
179 	struct fw_filter *f = arg;
180 	struct fw_filter __rcu **fp;
181 	struct fw_filter *pfp;
182 	int ret = -EINVAL;
183 	int h;
184 
185 	if (head == NULL || f == NULL)
186 		goto out;
187 
188 	fp = &head->ht[fw_hash(f->id)];
189 
190 	for (pfp = rtnl_dereference(*fp); pfp;
191 	     fp = &pfp->next, pfp = rtnl_dereference(*fp)) {
192 		if (pfp == f) {
193 			RCU_INIT_POINTER(*fp, rtnl_dereference(f->next));
194 			tcf_unbind_filter(tp, &f->res);
195 			tcf_exts_get_net(&f->exts);
196 			call_rcu(&f->rcu, fw_delete_filter);
197 			ret = 0;
198 			break;
199 		}
200 	}
201 
202 	*last = true;
203 	for (h = 0; h < HTSIZE; h++) {
204 		if (rcu_access_pointer(head->ht[h])) {
205 			*last = false;
206 			break;
207 		}
208 	}
209 
210 out:
211 	return ret;
212 }
213 
214 static const struct nla_policy fw_policy[TCA_FW_MAX + 1] = {
215 	[TCA_FW_CLASSID]	= { .type = NLA_U32 },
216 	[TCA_FW_INDEV]		= { .type = NLA_STRING, .len = IFNAMSIZ },
217 	[TCA_FW_MASK]		= { .type = NLA_U32 },
218 };
219 
220 static int fw_set_parms(struct net *net, struct tcf_proto *tp,
221 			struct fw_filter *f, struct nlattr **tb,
222 			struct nlattr **tca, unsigned long base, bool ovr,
223 			struct netlink_ext_ack *extack)
224 {
225 	struct fw_head *head = rtnl_dereference(tp->root);
226 	u32 mask;
227 	int err;
228 
229 	err = tcf_exts_validate(net, tp, tb, tca[TCA_RATE], &f->exts, ovr,
230 				extack);
231 	if (err < 0)
232 		return err;
233 
234 	if (tb[TCA_FW_CLASSID]) {
235 		f->res.classid = nla_get_u32(tb[TCA_FW_CLASSID]);
236 		tcf_bind_filter(tp, &f->res, base);
237 	}
238 
239 #ifdef CONFIG_NET_CLS_IND
240 	if (tb[TCA_FW_INDEV]) {
241 		int ret;
242 		ret = tcf_change_indev(net, tb[TCA_FW_INDEV], extack);
243 		if (ret < 0)
244 			return ret;
245 		f->ifindex = ret;
246 	}
247 #endif /* CONFIG_NET_CLS_IND */
248 
249 	err = -EINVAL;
250 	if (tb[TCA_FW_MASK]) {
251 		mask = nla_get_u32(tb[TCA_FW_MASK]);
252 		if (mask != head->mask)
253 			return err;
254 	} else if (head->mask != 0xFFFFFFFF)
255 		return err;
256 
257 	return 0;
258 }
259 
260 static int fw_change(struct net *net, struct sk_buff *in_skb,
261 		     struct tcf_proto *tp, unsigned long base,
262 		     u32 handle, struct nlattr **tca, void **arg,
263 		     bool ovr, struct netlink_ext_ack *extack)
264 {
265 	struct fw_head *head = rtnl_dereference(tp->root);
266 	struct fw_filter *f = *arg;
267 	struct nlattr *opt = tca[TCA_OPTIONS];
268 	struct nlattr *tb[TCA_FW_MAX + 1];
269 	int err;
270 
271 	if (!opt)
272 		return handle ? -EINVAL : 0; /* Succeed if it is old method. */
273 
274 	err = nla_parse_nested(tb, TCA_FW_MAX, opt, fw_policy, NULL);
275 	if (err < 0)
276 		return err;
277 
278 	if (f) {
279 		struct fw_filter *pfp, *fnew;
280 		struct fw_filter __rcu **fp;
281 
282 		if (f->id != handle && handle)
283 			return -EINVAL;
284 
285 		fnew = kzalloc(sizeof(struct fw_filter), GFP_KERNEL);
286 		if (!fnew)
287 			return -ENOBUFS;
288 
289 		fnew->id = f->id;
290 		fnew->res = f->res;
291 #ifdef CONFIG_NET_CLS_IND
292 		fnew->ifindex = f->ifindex;
293 #endif /* CONFIG_NET_CLS_IND */
294 		fnew->tp = f->tp;
295 
296 		err = tcf_exts_init(&fnew->exts, TCA_FW_ACT, TCA_FW_POLICE);
297 		if (err < 0) {
298 			kfree(fnew);
299 			return err;
300 		}
301 
302 		err = fw_set_parms(net, tp, fnew, tb, tca, base, ovr, extack);
303 		if (err < 0) {
304 			tcf_exts_destroy(&fnew->exts);
305 			kfree(fnew);
306 			return err;
307 		}
308 
309 		fp = &head->ht[fw_hash(fnew->id)];
310 		for (pfp = rtnl_dereference(*fp); pfp;
311 		     fp = &pfp->next, pfp = rtnl_dereference(*fp))
312 			if (pfp == f)
313 				break;
314 
315 		RCU_INIT_POINTER(fnew->next, rtnl_dereference(pfp->next));
316 		rcu_assign_pointer(*fp, fnew);
317 		tcf_unbind_filter(tp, &f->res);
318 		tcf_exts_get_net(&f->exts);
319 		call_rcu(&f->rcu, fw_delete_filter);
320 
321 		*arg = fnew;
322 		return err;
323 	}
324 
325 	if (!handle)
326 		return -EINVAL;
327 
328 	if (!head) {
329 		u32 mask = 0xFFFFFFFF;
330 		if (tb[TCA_FW_MASK])
331 			mask = nla_get_u32(tb[TCA_FW_MASK]);
332 
333 		head = kzalloc(sizeof(*head), GFP_KERNEL);
334 		if (!head)
335 			return -ENOBUFS;
336 		head->mask = mask;
337 
338 		rcu_assign_pointer(tp->root, head);
339 	}
340 
341 	f = kzalloc(sizeof(struct fw_filter), GFP_KERNEL);
342 	if (f == NULL)
343 		return -ENOBUFS;
344 
345 	err = tcf_exts_init(&f->exts, TCA_FW_ACT, TCA_FW_POLICE);
346 	if (err < 0)
347 		goto errout;
348 	f->id = handle;
349 	f->tp = tp;
350 
351 	err = fw_set_parms(net, tp, f, tb, tca, base, ovr, extack);
352 	if (err < 0)
353 		goto errout;
354 
355 	RCU_INIT_POINTER(f->next, head->ht[fw_hash(handle)]);
356 	rcu_assign_pointer(head->ht[fw_hash(handle)], f);
357 
358 	*arg = f;
359 	return 0;
360 
361 errout:
362 	tcf_exts_destroy(&f->exts);
363 	kfree(f);
364 	return err;
365 }
366 
367 static void fw_walk(struct tcf_proto *tp, struct tcf_walker *arg)
368 {
369 	struct fw_head *head = rtnl_dereference(tp->root);
370 	int h;
371 
372 	if (head == NULL)
373 		arg->stop = 1;
374 
375 	if (arg->stop)
376 		return;
377 
378 	for (h = 0; h < HTSIZE; h++) {
379 		struct fw_filter *f;
380 
381 		for (f = rtnl_dereference(head->ht[h]); f;
382 		     f = rtnl_dereference(f->next)) {
383 			if (arg->count < arg->skip) {
384 				arg->count++;
385 				continue;
386 			}
387 			if (arg->fn(tp, f, arg) < 0) {
388 				arg->stop = 1;
389 				return;
390 			}
391 			arg->count++;
392 		}
393 	}
394 }
395 
396 static int fw_dump(struct net *net, struct tcf_proto *tp, void *fh,
397 		   struct sk_buff *skb, struct tcmsg *t)
398 {
399 	struct fw_head *head = rtnl_dereference(tp->root);
400 	struct fw_filter *f = fh;
401 	struct nlattr *nest;
402 
403 	if (f == NULL)
404 		return skb->len;
405 
406 	t->tcm_handle = f->id;
407 
408 	if (!f->res.classid && !tcf_exts_has_actions(&f->exts))
409 		return skb->len;
410 
411 	nest = nla_nest_start(skb, TCA_OPTIONS);
412 	if (nest == NULL)
413 		goto nla_put_failure;
414 
415 	if (f->res.classid &&
416 	    nla_put_u32(skb, TCA_FW_CLASSID, f->res.classid))
417 		goto nla_put_failure;
418 #ifdef CONFIG_NET_CLS_IND
419 	if (f->ifindex) {
420 		struct net_device *dev;
421 		dev = __dev_get_by_index(net, f->ifindex);
422 		if (dev && nla_put_string(skb, TCA_FW_INDEV, dev->name))
423 			goto nla_put_failure;
424 	}
425 #endif /* CONFIG_NET_CLS_IND */
426 	if (head->mask != 0xFFFFFFFF &&
427 	    nla_put_u32(skb, TCA_FW_MASK, head->mask))
428 		goto nla_put_failure;
429 
430 	if (tcf_exts_dump(skb, &f->exts) < 0)
431 		goto nla_put_failure;
432 
433 	nla_nest_end(skb, nest);
434 
435 	if (tcf_exts_dump_stats(skb, &f->exts) < 0)
436 		goto nla_put_failure;
437 
438 	return skb->len;
439 
440 nla_put_failure:
441 	nla_nest_cancel(skb, nest);
442 	return -1;
443 }
444 
445 static void fw_bind_class(void *fh, u32 classid, unsigned long cl)
446 {
447 	struct fw_filter *f = fh;
448 
449 	if (f && f->res.classid == classid)
450 		f->res.class = cl;
451 }
452 
453 static struct tcf_proto_ops cls_fw_ops __read_mostly = {
454 	.kind		=	"fw",
455 	.classify	=	fw_classify,
456 	.init		=	fw_init,
457 	.destroy	=	fw_destroy,
458 	.get		=	fw_get,
459 	.change		=	fw_change,
460 	.delete		=	fw_delete,
461 	.walk		=	fw_walk,
462 	.dump		=	fw_dump,
463 	.bind_class	=	fw_bind_class,
464 	.owner		=	THIS_MODULE,
465 };
466 
467 static int __init init_fw(void)
468 {
469 	return register_tcf_proto_ops(&cls_fw_ops);
470 }
471 
472 static void __exit exit_fw(void)
473 {
474 	unregister_tcf_proto_ops(&cls_fw_ops);
475 }
476 
477 module_init(init_fw)
478 module_exit(exit_fw)
479 MODULE_LICENSE("GPL");
480