xref: /openbmc/linux/net/sched/cls_fw.c (revision 239480ab) 
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 	struct rcu_head		rcu;
50 };
51 
52 static u32 fw_hash(u32 handle)
53 {
54 	handle ^= (handle >> 16);
55 	handle ^= (handle >> 8);
56 	return handle % HTSIZE;
57 }
58 
59 static int fw_classify(struct sk_buff *skb, const struct tcf_proto *tp,
60 		       struct tcf_result *res)
61 {
62 	struct fw_head *head = rcu_dereference_bh(tp->root);
63 	struct fw_filter *f;
64 	int r;
65 	u32 id = skb->mark;
66 
67 	if (head != NULL) {
68 		id &= head->mask;
69 
70 		for (f = rcu_dereference_bh(head->ht[fw_hash(id)]); f;
71 		     f = rcu_dereference_bh(f->next)) {
72 			if (f->id == id) {
73 				*res = f->res;
74 #ifdef CONFIG_NET_CLS_IND
75 				if (!tcf_match_indev(skb, f->ifindex))
76 					continue;
77 #endif /* CONFIG_NET_CLS_IND */
78 				r = tcf_exts_exec(skb, &f->exts, res);
79 				if (r < 0)
80 					continue;
81 
82 				return r;
83 			}
84 		}
85 	} else {
86 		/* Old method: classify the packet using its skb mark. */
87 		if (id && (TC_H_MAJ(id) == 0 ||
88 			   !(TC_H_MAJ(id ^ tp->q->handle)))) {
89 			res->classid = id;
90 			res->class = 0;
91 			return 0;
92 		}
93 	}
94 
95 	return -1;
96 }
97 
98 static unsigned long fw_get(struct tcf_proto *tp, u32 handle)
99 {
100 	struct fw_head *head = rtnl_dereference(tp->root);
101 	struct fw_filter *f;
102 
103 	if (head == NULL)
104 		return 0;
105 
106 	f = rtnl_dereference(head->ht[fw_hash(handle)]);
107 	for (; f; f = rtnl_dereference(f->next)) {
108 		if (f->id == handle)
109 			return (unsigned long)f;
110 	}
111 	return 0;
112 }
113 
114 static int fw_init(struct tcf_proto *tp)
115 {
116 	/* We don't allocate fw_head here, because in the old method
117 	 * we don't need it at all.
118 	 */
119 	return 0;
120 }
121 
122 static void fw_delete_filter(struct rcu_head *head)
123 {
124 	struct fw_filter *f = container_of(head, struct fw_filter, rcu);
125 
126 	tcf_exts_destroy(&f->exts);
127 	kfree(f);
128 }
129 
130 static void fw_destroy(struct tcf_proto *tp)
131 {
132 	struct fw_head *head = rtnl_dereference(tp->root);
133 	struct fw_filter *f;
134 	int h;
135 
136 	if (head == NULL)
137 		return;
138 
139 	for (h = 0; h < HTSIZE; h++) {
140 		while ((f = rtnl_dereference(head->ht[h])) != NULL) {
141 			RCU_INIT_POINTER(head->ht[h],
142 					 rtnl_dereference(f->next));
143 			tcf_unbind_filter(tp, &f->res);
144 			call_rcu(&f->rcu, fw_delete_filter);
145 		}
146 	}
147 	kfree_rcu(head, rcu);
148 }
149 
150 static int fw_delete(struct tcf_proto *tp, unsigned long arg, bool *last)
151 {
152 	struct fw_head *head = rtnl_dereference(tp->root);
153 	struct fw_filter *f = (struct fw_filter *)arg;
154 	struct fw_filter __rcu **fp;
155 	struct fw_filter *pfp;
156 	int ret = -EINVAL;
157 	int h;
158 
159 	if (head == NULL || f == NULL)
160 		goto out;
161 
162 	fp = &head->ht[fw_hash(f->id)];
163 
164 	for (pfp = rtnl_dereference(*fp); pfp;
165 	     fp = &pfp->next, pfp = rtnl_dereference(*fp)) {
166 		if (pfp == f) {
167 			RCU_INIT_POINTER(*fp, rtnl_dereference(f->next));
168 			tcf_unbind_filter(tp, &f->res);
169 			call_rcu(&f->rcu, fw_delete_filter);
170 			ret = 0;
171 			break;
172 		}
173 	}
174 
175 	*last = true;
176 	for (h = 0; h < HTSIZE; h++) {
177 		if (rcu_access_pointer(head->ht[h])) {
178 			*last = false;
179 			break;
180 		}
181 	}
182 
183 out:
184 	return ret;
185 }
186 
187 static const struct nla_policy fw_policy[TCA_FW_MAX + 1] = {
188 	[TCA_FW_CLASSID]	= { .type = NLA_U32 },
189 	[TCA_FW_INDEV]		= { .type = NLA_STRING, .len = IFNAMSIZ },
190 	[TCA_FW_MASK]		= { .type = NLA_U32 },
191 };
192 
193 static int
194 fw_change_attrs(struct net *net, struct tcf_proto *tp, struct fw_filter *f,
195 		struct nlattr **tb, struct nlattr **tca, unsigned long base,
196 		bool ovr)
197 {
198 	struct fw_head *head = rtnl_dereference(tp->root);
199 	struct tcf_exts e;
200 	u32 mask;
201 	int err;
202 
203 	err = tcf_exts_init(&e, TCA_FW_ACT, TCA_FW_POLICE);
204 	if (err < 0)
205 		return err;
206 	err = tcf_exts_validate(net, tp, tb, tca[TCA_RATE], &e, ovr);
207 	if (err < 0)
208 		goto errout;
209 
210 	if (tb[TCA_FW_CLASSID]) {
211 		f->res.classid = nla_get_u32(tb[TCA_FW_CLASSID]);
212 		tcf_bind_filter(tp, &f->res, base);
213 	}
214 
215 #ifdef CONFIG_NET_CLS_IND
216 	if (tb[TCA_FW_INDEV]) {
217 		int ret;
218 		ret = tcf_change_indev(net, tb[TCA_FW_INDEV]);
219 		if (ret < 0) {
220 			err = ret;
221 			goto errout;
222 		}
223 		f->ifindex = ret;
224 	}
225 #endif /* CONFIG_NET_CLS_IND */
226 
227 	err = -EINVAL;
228 	if (tb[TCA_FW_MASK]) {
229 		mask = nla_get_u32(tb[TCA_FW_MASK]);
230 		if (mask != head->mask)
231 			goto errout;
232 	} else if (head->mask != 0xFFFFFFFF)
233 		goto errout;
234 
235 	tcf_exts_change(tp, &f->exts, &e);
236 
237 	return 0;
238 errout:
239 	tcf_exts_destroy(&e);
240 	return err;
241 }
242 
243 static int fw_change(struct net *net, struct sk_buff *in_skb,
244 		     struct tcf_proto *tp, unsigned long base,
245 		     u32 handle, struct nlattr **tca, unsigned long *arg,
246 		     bool ovr)
247 {
248 	struct fw_head *head = rtnl_dereference(tp->root);
249 	struct fw_filter *f = (struct fw_filter *) *arg;
250 	struct nlattr *opt = tca[TCA_OPTIONS];
251 	struct nlattr *tb[TCA_FW_MAX + 1];
252 	int err;
253 
254 	if (!opt)
255 		return handle ? -EINVAL : 0; /* Succeed if it is old method. */
256 
257 	err = nla_parse_nested(tb, TCA_FW_MAX, opt, fw_policy, NULL);
258 	if (err < 0)
259 		return err;
260 
261 	if (f) {
262 		struct fw_filter *pfp, *fnew;
263 		struct fw_filter __rcu **fp;
264 
265 		if (f->id != handle && handle)
266 			return -EINVAL;
267 
268 		fnew = kzalloc(sizeof(struct fw_filter), GFP_KERNEL);
269 		if (!fnew)
270 			return -ENOBUFS;
271 
272 		fnew->id = f->id;
273 		fnew->res = f->res;
274 #ifdef CONFIG_NET_CLS_IND
275 		fnew->ifindex = f->ifindex;
276 #endif /* CONFIG_NET_CLS_IND */
277 		fnew->tp = f->tp;
278 
279 		err = tcf_exts_init(&fnew->exts, TCA_FW_ACT, TCA_FW_POLICE);
280 		if (err < 0) {
281 			kfree(fnew);
282 			return err;
283 		}
284 
285 		err = fw_change_attrs(net, tp, fnew, tb, tca, base, ovr);
286 		if (err < 0) {
287 			tcf_exts_destroy(&fnew->exts);
288 			kfree(fnew);
289 			return err;
290 		}
291 
292 		fp = &head->ht[fw_hash(fnew->id)];
293 		for (pfp = rtnl_dereference(*fp); pfp;
294 		     fp = &pfp->next, pfp = rtnl_dereference(*fp))
295 			if (pfp == f)
296 				break;
297 
298 		RCU_INIT_POINTER(fnew->next, rtnl_dereference(pfp->next));
299 		rcu_assign_pointer(*fp, fnew);
300 		tcf_unbind_filter(tp, &f->res);
301 		call_rcu(&f->rcu, fw_delete_filter);
302 
303 		*arg = (unsigned long)fnew;
304 		return err;
305 	}
306 
307 	if (!handle)
308 		return -EINVAL;
309 
310 	if (!head) {
311 		u32 mask = 0xFFFFFFFF;
312 		if (tb[TCA_FW_MASK])
313 			mask = nla_get_u32(tb[TCA_FW_MASK]);
314 
315 		head = kzalloc(sizeof(*head), GFP_KERNEL);
316 		if (!head)
317 			return -ENOBUFS;
318 		head->mask = mask;
319 
320 		rcu_assign_pointer(tp->root, head);
321 	}
322 
323 	f = kzalloc(sizeof(struct fw_filter), GFP_KERNEL);
324 	if (f == NULL)
325 		return -ENOBUFS;
326 
327 	err = tcf_exts_init(&f->exts, TCA_FW_ACT, TCA_FW_POLICE);
328 	if (err < 0)
329 		goto errout;
330 	f->id = handle;
331 	f->tp = tp;
332 
333 	err = fw_change_attrs(net, tp, f, tb, tca, base, ovr);
334 	if (err < 0)
335 		goto errout;
336 
337 	RCU_INIT_POINTER(f->next, head->ht[fw_hash(handle)]);
338 	rcu_assign_pointer(head->ht[fw_hash(handle)], f);
339 
340 	*arg = (unsigned long)f;
341 	return 0;
342 
343 errout:
344 	tcf_exts_destroy(&f->exts);
345 	kfree(f);
346 	return err;
347 }
348 
349 static void fw_walk(struct tcf_proto *tp, struct tcf_walker *arg)
350 {
351 	struct fw_head *head = rtnl_dereference(tp->root);
352 	int h;
353 
354 	if (head == NULL)
355 		arg->stop = 1;
356 
357 	if (arg->stop)
358 		return;
359 
360 	for (h = 0; h < HTSIZE; h++) {
361 		struct fw_filter *f;
362 
363 		for (f = rtnl_dereference(head->ht[h]); f;
364 		     f = rtnl_dereference(f->next)) {
365 			if (arg->count < arg->skip) {
366 				arg->count++;
367 				continue;
368 			}
369 			if (arg->fn(tp, (unsigned long)f, arg) < 0) {
370 				arg->stop = 1;
371 				return;
372 			}
373 			arg->count++;
374 		}
375 	}
376 }
377 
378 static int fw_dump(struct net *net, struct tcf_proto *tp, unsigned long fh,
379 		   struct sk_buff *skb, struct tcmsg *t)
380 {
381 	struct fw_head *head = rtnl_dereference(tp->root);
382 	struct fw_filter *f = (struct fw_filter *)fh;
383 	struct nlattr *nest;
384 
385 	if (f == NULL)
386 		return skb->len;
387 
388 	t->tcm_handle = f->id;
389 
390 	if (!f->res.classid && !tcf_exts_is_available(&f->exts))
391 		return skb->len;
392 
393 	nest = nla_nest_start(skb, TCA_OPTIONS);
394 	if (nest == NULL)
395 		goto nla_put_failure;
396 
397 	if (f->res.classid &&
398 	    nla_put_u32(skb, TCA_FW_CLASSID, f->res.classid))
399 		goto nla_put_failure;
400 #ifdef CONFIG_NET_CLS_IND
401 	if (f->ifindex) {
402 		struct net_device *dev;
403 		dev = __dev_get_by_index(net, f->ifindex);
404 		if (dev && nla_put_string(skb, TCA_FW_INDEV, dev->name))
405 			goto nla_put_failure;
406 	}
407 #endif /* CONFIG_NET_CLS_IND */
408 	if (head->mask != 0xFFFFFFFF &&
409 	    nla_put_u32(skb, TCA_FW_MASK, head->mask))
410 		goto nla_put_failure;
411 
412 	if (tcf_exts_dump(skb, &f->exts) < 0)
413 		goto nla_put_failure;
414 
415 	nla_nest_end(skb, nest);
416 
417 	if (tcf_exts_dump_stats(skb, &f->exts) < 0)
418 		goto nla_put_failure;
419 
420 	return skb->len;
421 
422 nla_put_failure:
423 	nla_nest_cancel(skb, nest);
424 	return -1;
425 }
426 
427 static struct tcf_proto_ops cls_fw_ops __read_mostly = {
428 	.kind		=	"fw",
429 	.classify	=	fw_classify,
430 	.init		=	fw_init,
431 	.destroy	=	fw_destroy,
432 	.get		=	fw_get,
433 	.change		=	fw_change,
434 	.delete		=	fw_delete,
435 	.walk		=	fw_walk,
436 	.dump		=	fw_dump,
437 	.owner		=	THIS_MODULE,
438 };
439 
440 static int __init init_fw(void)
441 {
442 	return register_tcf_proto_ops(&cls_fw_ops);
443 }
444 
445 static void __exit exit_fw(void)
446 {
447 	unregister_tcf_proto_ops(&cls_fw_ops);
448 }
449 
450 module_init(init_fw)
451 module_exit(exit_fw)
452 MODULE_LICENSE("GPL");
453