xref: /linux/net/sched/cls_fw.c (revision 995231c820e3bd3633cb38bf4ea6f2541e1da331) 
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_head		rcu;
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 rcu_head *head)
126 {
127 	struct fw_filter *f = container_of(head, struct fw_filter, rcu);
128 
129 	tcf_exts_destroy(&f->exts);
130 	kfree(f);
131 }
132 
133 static void fw_destroy(struct tcf_proto *tp)
134 {
135 	struct fw_head *head = rtnl_dereference(tp->root);
136 	struct fw_filter *f;
137 	int h;
138 
139 	if (head == NULL)
140 		return;
141 
142 	for (h = 0; h < HTSIZE; h++) {
143 		while ((f = rtnl_dereference(head->ht[h])) != NULL) {
144 			RCU_INIT_POINTER(head->ht[h],
145 					 rtnl_dereference(f->next));
146 			tcf_unbind_filter(tp, &f->res);
147 			call_rcu(&f->rcu, fw_delete_filter);
148 		}
149 	}
150 	kfree_rcu(head, rcu);
151 }
152 
153 static int fw_delete(struct tcf_proto *tp, void *arg, bool *last)
154 {
155 	struct fw_head *head = rtnl_dereference(tp->root);
156 	struct fw_filter *f = arg;
157 	struct fw_filter __rcu **fp;
158 	struct fw_filter *pfp;
159 	int ret = -EINVAL;
160 	int h;
161 
162 	if (head == NULL || f == NULL)
163 		goto out;
164 
165 	fp = &head->ht[fw_hash(f->id)];
166 
167 	for (pfp = rtnl_dereference(*fp); pfp;
168 	     fp = &pfp->next, pfp = rtnl_dereference(*fp)) {
169 		if (pfp == f) {
170 			RCU_INIT_POINTER(*fp, rtnl_dereference(f->next));
171 			tcf_unbind_filter(tp, &f->res);
172 			call_rcu(&f->rcu, fw_delete_filter);
173 			ret = 0;
174 			break;
175 		}
176 	}
177 
178 	*last = true;
179 	for (h = 0; h < HTSIZE; h++) {
180 		if (rcu_access_pointer(head->ht[h])) {
181 			*last = false;
182 			break;
183 		}
184 	}
185 
186 out:
187 	return ret;
188 }
189 
190 static const struct nla_policy fw_policy[TCA_FW_MAX + 1] = {
191 	[TCA_FW_CLASSID]	= { .type = NLA_U32 },
192 	[TCA_FW_INDEV]		= { .type = NLA_STRING, .len = IFNAMSIZ },
193 	[TCA_FW_MASK]		= { .type = NLA_U32 },
194 };
195 
196 static int fw_set_parms(struct net *net, struct tcf_proto *tp,
197 			struct fw_filter *f, struct nlattr **tb,
198 			struct nlattr **tca, unsigned long base, bool ovr)
199 {
200 	struct fw_head *head = rtnl_dereference(tp->root);
201 	u32 mask;
202 	int err;
203 
204 	err = tcf_exts_validate(net, tp, tb, tca[TCA_RATE], &f->exts, ovr);
205 	if (err < 0)
206 		return err;
207 
208 	if (tb[TCA_FW_CLASSID]) {
209 		f->res.classid = nla_get_u32(tb[TCA_FW_CLASSID]);
210 		tcf_bind_filter(tp, &f->res, base);
211 	}
212 
213 #ifdef CONFIG_NET_CLS_IND
214 	if (tb[TCA_FW_INDEV]) {
215 		int ret;
216 		ret = tcf_change_indev(net, tb[TCA_FW_INDEV]);
217 		if (ret < 0)
218 			return ret;
219 		f->ifindex = ret;
220 	}
221 #endif /* CONFIG_NET_CLS_IND */
222 
223 	err = -EINVAL;
224 	if (tb[TCA_FW_MASK]) {
225 		mask = nla_get_u32(tb[TCA_FW_MASK]);
226 		if (mask != head->mask)
227 			return err;
228 	} else if (head->mask != 0xFFFFFFFF)
229 		return err;
230 
231 	return 0;
232 }
233 
234 static int fw_change(struct net *net, struct sk_buff *in_skb,
235 		     struct tcf_proto *tp, unsigned long base,
236 		     u32 handle, struct nlattr **tca, void **arg,
237 		     bool ovr)
238 {
239 	struct fw_head *head = rtnl_dereference(tp->root);
240 	struct fw_filter *f = *arg;
241 	struct nlattr *opt = tca[TCA_OPTIONS];
242 	struct nlattr *tb[TCA_FW_MAX + 1];
243 	int err;
244 
245 	if (!opt)
246 		return handle ? -EINVAL : 0; /* Succeed if it is old method. */
247 
248 	err = nla_parse_nested(tb, TCA_FW_MAX, opt, fw_policy, NULL);
249 	if (err < 0)
250 		return err;
251 
252 	if (f) {
253 		struct fw_filter *pfp, *fnew;
254 		struct fw_filter __rcu **fp;
255 
256 		if (f->id != handle && handle)
257 			return -EINVAL;
258 
259 		fnew = kzalloc(sizeof(struct fw_filter), GFP_KERNEL);
260 		if (!fnew)
261 			return -ENOBUFS;
262 
263 		fnew->id = f->id;
264 		fnew->res = f->res;
265 #ifdef CONFIG_NET_CLS_IND
266 		fnew->ifindex = f->ifindex;
267 #endif /* CONFIG_NET_CLS_IND */
268 		fnew->tp = f->tp;
269 
270 		err = tcf_exts_init(&fnew->exts, TCA_FW_ACT, TCA_FW_POLICE);
271 		if (err < 0) {
272 			kfree(fnew);
273 			return err;
274 		}
275 
276 		err = fw_set_parms(net, tp, fnew, tb, tca, base, ovr);
277 		if (err < 0) {
278 			tcf_exts_destroy(&fnew->exts);
279 			kfree(fnew);
280 			return err;
281 		}
282 
283 		fp = &head->ht[fw_hash(fnew->id)];
284 		for (pfp = rtnl_dereference(*fp); pfp;
285 		     fp = &pfp->next, pfp = rtnl_dereference(*fp))
286 			if (pfp == f)
287 				break;
288 
289 		RCU_INIT_POINTER(fnew->next, rtnl_dereference(pfp->next));
290 		rcu_assign_pointer(*fp, fnew);
291 		tcf_unbind_filter(tp, &f->res);
292 		call_rcu(&f->rcu, fw_delete_filter);
293 
294 		*arg = fnew;
295 		return err;
296 	}
297 
298 	if (!handle)
299 		return -EINVAL;
300 
301 	if (!head) {
302 		u32 mask = 0xFFFFFFFF;
303 		if (tb[TCA_FW_MASK])
304 			mask = nla_get_u32(tb[TCA_FW_MASK]);
305 
306 		head = kzalloc(sizeof(*head), GFP_KERNEL);
307 		if (!head)
308 			return -ENOBUFS;
309 		head->mask = mask;
310 
311 		rcu_assign_pointer(tp->root, head);
312 	}
313 
314 	f = kzalloc(sizeof(struct fw_filter), GFP_KERNEL);
315 	if (f == NULL)
316 		return -ENOBUFS;
317 
318 	err = tcf_exts_init(&f->exts, TCA_FW_ACT, TCA_FW_POLICE);
319 	if (err < 0)
320 		goto errout;
321 	f->id = handle;
322 	f->tp = tp;
323 
324 	err = fw_set_parms(net, tp, f, tb, tca, base, ovr);
325 	if (err < 0)
326 		goto errout;
327 
328 	RCU_INIT_POINTER(f->next, head->ht[fw_hash(handle)]);
329 	rcu_assign_pointer(head->ht[fw_hash(handle)], f);
330 
331 	*arg = f;
332 	return 0;
333 
334 errout:
335 	tcf_exts_destroy(&f->exts);
336 	kfree(f);
337 	return err;
338 }
339 
340 static void fw_walk(struct tcf_proto *tp, struct tcf_walker *arg)
341 {
342 	struct fw_head *head = rtnl_dereference(tp->root);
343 	int h;
344 
345 	if (head == NULL)
346 		arg->stop = 1;
347 
348 	if (arg->stop)
349 		return;
350 
351 	for (h = 0; h < HTSIZE; h++) {
352 		struct fw_filter *f;
353 
354 		for (f = rtnl_dereference(head->ht[h]); f;
355 		     f = rtnl_dereference(f->next)) {
356 			if (arg->count < arg->skip) {
357 				arg->count++;
358 				continue;
359 			}
360 			if (arg->fn(tp, f, arg) < 0) {
361 				arg->stop = 1;
362 				return;
363 			}
364 			arg->count++;
365 		}
366 	}
367 }
368 
369 static int fw_dump(struct net *net, struct tcf_proto *tp, void *fh,
370 		   struct sk_buff *skb, struct tcmsg *t)
371 {
372 	struct fw_head *head = rtnl_dereference(tp->root);
373 	struct fw_filter *f = fh;
374 	struct nlattr *nest;
375 
376 	if (f == NULL)
377 		return skb->len;
378 
379 	t->tcm_handle = f->id;
380 
381 	if (!f->res.classid && !tcf_exts_has_actions(&f->exts))
382 		return skb->len;
383 
384 	nest = nla_nest_start(skb, TCA_OPTIONS);
385 	if (nest == NULL)
386 		goto nla_put_failure;
387 
388 	if (f->res.classid &&
389 	    nla_put_u32(skb, TCA_FW_CLASSID, f->res.classid))
390 		goto nla_put_failure;
391 #ifdef CONFIG_NET_CLS_IND
392 	if (f->ifindex) {
393 		struct net_device *dev;
394 		dev = __dev_get_by_index(net, f->ifindex);
395 		if (dev && nla_put_string(skb, TCA_FW_INDEV, dev->name))
396 			goto nla_put_failure;
397 	}
398 #endif /* CONFIG_NET_CLS_IND */
399 	if (head->mask != 0xFFFFFFFF &&
400 	    nla_put_u32(skb, TCA_FW_MASK, head->mask))
401 		goto nla_put_failure;
402 
403 	if (tcf_exts_dump(skb, &f->exts) < 0)
404 		goto nla_put_failure;
405 
406 	nla_nest_end(skb, nest);
407 
408 	if (tcf_exts_dump_stats(skb, &f->exts) < 0)
409 		goto nla_put_failure;
410 
411 	return skb->len;
412 
413 nla_put_failure:
414 	nla_nest_cancel(skb, nest);
415 	return -1;
416 }
417 
418 static void fw_bind_class(void *fh, u32 classid, unsigned long cl)
419 {
420 	struct fw_filter *f = fh;
421 
422 	if (f && f->res.classid == classid)
423 		f->res.class = cl;
424 }
425 
426 static struct tcf_proto_ops cls_fw_ops __read_mostly = {
427 	.kind		=	"fw",
428 	.classify	=	fw_classify,
429 	.init		=	fw_init,
430 	.destroy	=	fw_destroy,
431 	.get		=	fw_get,
432 	.change		=	fw_change,
433 	.delete		=	fw_delete,
434 	.walk		=	fw_walk,
435 	.dump		=	fw_dump,
436 	.bind_class	=	fw_bind_class,
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