xref: /linux/net/sched/cls_fw.c (revision 4949009eb8d40a441dcddcd96e101e77d31cf1b2)
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 */
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 	return 0;
117 }
118 
119 static void fw_delete_filter(struct rcu_head *head)
120 {
121 	struct fw_filter *f = container_of(head, struct fw_filter, rcu);
122 
123 	tcf_exts_destroy(&f->exts);
124 	kfree(f);
125 }
126 
127 static void fw_destroy(struct tcf_proto *tp)
128 {
129 	struct fw_head *head = rtnl_dereference(tp->root);
130 	struct fw_filter *f;
131 	int h;
132 
133 	if (head == NULL)
134 		return;
135 
136 	for (h = 0; h < HTSIZE; h++) {
137 		while ((f = rtnl_dereference(head->ht[h])) != NULL) {
138 			RCU_INIT_POINTER(head->ht[h],
139 					 rtnl_dereference(f->next));
140 			tcf_unbind_filter(tp, &f->res);
141 			call_rcu(&f->rcu, fw_delete_filter);
142 		}
143 	}
144 	RCU_INIT_POINTER(tp->root, NULL);
145 	kfree_rcu(head, rcu);
146 }
147 
148 static int fw_delete(struct tcf_proto *tp, unsigned long arg)
149 {
150 	struct fw_head *head = rtnl_dereference(tp->root);
151 	struct fw_filter *f = (struct fw_filter *)arg;
152 	struct fw_filter __rcu **fp;
153 	struct fw_filter *pfp;
154 
155 	if (head == NULL || f == NULL)
156 		goto out;
157 
158 	fp = &head->ht[fw_hash(f->id)];
159 
160 	for (pfp = rtnl_dereference(*fp); pfp;
161 	     fp = &pfp->next, pfp = rtnl_dereference(*fp)) {
162 		if (pfp == f) {
163 			RCU_INIT_POINTER(*fp, rtnl_dereference(f->next));
164 			tcf_unbind_filter(tp, &f->res);
165 			call_rcu(&f->rcu, fw_delete_filter);
166 			return 0;
167 		}
168 	}
169 out:
170 	return -EINVAL;
171 }
172 
173 static const struct nla_policy fw_policy[TCA_FW_MAX + 1] = {
174 	[TCA_FW_CLASSID]	= { .type = NLA_U32 },
175 	[TCA_FW_INDEV]		= { .type = NLA_STRING, .len = IFNAMSIZ },
176 	[TCA_FW_MASK]		= { .type = NLA_U32 },
177 };
178 
179 static int
180 fw_change_attrs(struct net *net, struct tcf_proto *tp, struct fw_filter *f,
181 	struct nlattr **tb, struct nlattr **tca, unsigned long base, bool ovr)
182 {
183 	struct fw_head *head = rtnl_dereference(tp->root);
184 	struct tcf_exts e;
185 	u32 mask;
186 	int err;
187 
188 	tcf_exts_init(&e, TCA_FW_ACT, TCA_FW_POLICE);
189 	err = tcf_exts_validate(net, tp, tb, tca[TCA_RATE], &e, ovr);
190 	if (err < 0)
191 		return err;
192 
193 	if (tb[TCA_FW_CLASSID]) {
194 		f->res.classid = nla_get_u32(tb[TCA_FW_CLASSID]);
195 		tcf_bind_filter(tp, &f->res, base);
196 	}
197 
198 #ifdef CONFIG_NET_CLS_IND
199 	if (tb[TCA_FW_INDEV]) {
200 		int ret;
201 		ret = tcf_change_indev(net, tb[TCA_FW_INDEV]);
202 		if (ret < 0) {
203 			err = ret;
204 			goto errout;
205 		}
206 		f->ifindex = ret;
207 	}
208 #endif /* CONFIG_NET_CLS_IND */
209 
210 	err = -EINVAL;
211 	if (tb[TCA_FW_MASK]) {
212 		mask = nla_get_u32(tb[TCA_FW_MASK]);
213 		if (mask != head->mask)
214 			goto errout;
215 	} else if (head->mask != 0xFFFFFFFF)
216 		goto errout;
217 
218 	tcf_exts_change(tp, &f->exts, &e);
219 
220 	return 0;
221 errout:
222 	tcf_exts_destroy(&e);
223 	return err;
224 }
225 
226 static int fw_change(struct net *net, struct sk_buff *in_skb,
227 		     struct tcf_proto *tp, unsigned long base,
228 		     u32 handle,
229 		     struct nlattr **tca,
230 		     unsigned long *arg, bool ovr)
231 {
232 	struct fw_head *head = rtnl_dereference(tp->root);
233 	struct fw_filter *f = (struct fw_filter *) *arg;
234 	struct nlattr *opt = tca[TCA_OPTIONS];
235 	struct nlattr *tb[TCA_FW_MAX + 1];
236 	int err;
237 
238 	if (!opt)
239 		return handle ? -EINVAL : 0;
240 
241 	err = nla_parse_nested(tb, TCA_FW_MAX, opt, fw_policy);
242 	if (err < 0)
243 		return err;
244 
245 	if (f) {
246 		struct fw_filter *pfp, *fnew;
247 		struct fw_filter __rcu **fp;
248 
249 		if (f->id != handle && handle)
250 			return -EINVAL;
251 
252 		fnew = kzalloc(sizeof(struct fw_filter), GFP_KERNEL);
253 		if (!fnew)
254 			return -ENOBUFS;
255 
256 		fnew->id = f->id;
257 		fnew->res = f->res;
258 #ifdef CONFIG_NET_CLS_IND
259 		fnew->ifindex = f->ifindex;
260 #endif /* CONFIG_NET_CLS_IND */
261 		fnew->tp = f->tp;
262 
263 		tcf_exts_init(&fnew->exts, TCA_FW_ACT, TCA_FW_POLICE);
264 
265 		err = fw_change_attrs(net, tp, fnew, tb, tca, base, ovr);
266 		if (err < 0) {
267 			kfree(fnew);
268 			return err;
269 		}
270 
271 		fp = &head->ht[fw_hash(fnew->id)];
272 		for (pfp = rtnl_dereference(*fp); pfp;
273 		     fp = &pfp->next, pfp = rtnl_dereference(*fp))
274 			if (pfp == f)
275 				break;
276 
277 		RCU_INIT_POINTER(fnew->next, rtnl_dereference(pfp->next));
278 		rcu_assign_pointer(*fp, fnew);
279 		tcf_unbind_filter(tp, &f->res);
280 		call_rcu(&f->rcu, fw_delete_filter);
281 
282 		*arg = (unsigned long)fnew;
283 		return err;
284 	}
285 
286 	if (!handle)
287 		return -EINVAL;
288 
289 	if (head == NULL) {
290 		u32 mask = 0xFFFFFFFF;
291 		if (tb[TCA_FW_MASK])
292 			mask = nla_get_u32(tb[TCA_FW_MASK]);
293 
294 		head = kzalloc(sizeof(struct fw_head), GFP_KERNEL);
295 		if (head == NULL)
296 			return -ENOBUFS;
297 		head->mask = mask;
298 
299 		rcu_assign_pointer(tp->root, head);
300 	}
301 
302 	f = kzalloc(sizeof(struct fw_filter), GFP_KERNEL);
303 	if (f == NULL)
304 		return -ENOBUFS;
305 
306 	tcf_exts_init(&f->exts, TCA_FW_ACT, TCA_FW_POLICE);
307 	f->id = handle;
308 	f->tp = tp;
309 
310 	err = fw_change_attrs(net, tp, f, tb, tca, base, ovr);
311 	if (err < 0)
312 		goto errout;
313 
314 	RCU_INIT_POINTER(f->next, head->ht[fw_hash(handle)]);
315 	rcu_assign_pointer(head->ht[fw_hash(handle)], f);
316 
317 	*arg = (unsigned long)f;
318 	return 0;
319 
320 errout:
321 	kfree(f);
322 	return err;
323 }
324 
325 static void fw_walk(struct tcf_proto *tp, struct tcf_walker *arg)
326 {
327 	struct fw_head *head = rtnl_dereference(tp->root);
328 	int h;
329 
330 	if (head == NULL)
331 		arg->stop = 1;
332 
333 	if (arg->stop)
334 		return;
335 
336 	for (h = 0; h < HTSIZE; h++) {
337 		struct fw_filter *f;
338 
339 		for (f = rtnl_dereference(head->ht[h]); f;
340 		     f = rtnl_dereference(f->next)) {
341 			if (arg->count < arg->skip) {
342 				arg->count++;
343 				continue;
344 			}
345 			if (arg->fn(tp, (unsigned long)f, arg) < 0) {
346 				arg->stop = 1;
347 				return;
348 			}
349 			arg->count++;
350 		}
351 	}
352 }
353 
354 static int fw_dump(struct net *net, struct tcf_proto *tp, unsigned long fh,
355 		   struct sk_buff *skb, struct tcmsg *t)
356 {
357 	struct fw_head *head = rtnl_dereference(tp->root);
358 	struct fw_filter *f = (struct fw_filter *)fh;
359 	struct nlattr *nest;
360 
361 	if (f == NULL)
362 		return skb->len;
363 
364 	t->tcm_handle = f->id;
365 
366 	if (!f->res.classid && !tcf_exts_is_available(&f->exts))
367 		return skb->len;
368 
369 	nest = nla_nest_start(skb, TCA_OPTIONS);
370 	if (nest == NULL)
371 		goto nla_put_failure;
372 
373 	if (f->res.classid &&
374 	    nla_put_u32(skb, TCA_FW_CLASSID, f->res.classid))
375 		goto nla_put_failure;
376 #ifdef CONFIG_NET_CLS_IND
377 	if (f->ifindex) {
378 		struct net_device *dev;
379 		dev = __dev_get_by_index(net, f->ifindex);
380 		if (dev && nla_put_string(skb, TCA_FW_INDEV, dev->name))
381 			goto nla_put_failure;
382 	}
383 #endif /* CONFIG_NET_CLS_IND */
384 	if (head->mask != 0xFFFFFFFF &&
385 	    nla_put_u32(skb, TCA_FW_MASK, head->mask))
386 		goto nla_put_failure;
387 
388 	if (tcf_exts_dump(skb, &f->exts) < 0)
389 		goto nla_put_failure;
390 
391 	nla_nest_end(skb, nest);
392 
393 	if (tcf_exts_dump_stats(skb, &f->exts) < 0)
394 		goto nla_put_failure;
395 
396 	return skb->len;
397 
398 nla_put_failure:
399 	nla_nest_cancel(skb, nest);
400 	return -1;
401 }
402 
403 static struct tcf_proto_ops cls_fw_ops __read_mostly = {
404 	.kind		=	"fw",
405 	.classify	=	fw_classify,
406 	.init		=	fw_init,
407 	.destroy	=	fw_destroy,
408 	.get		=	fw_get,
409 	.change		=	fw_change,
410 	.delete		=	fw_delete,
411 	.walk		=	fw_walk,
412 	.dump		=	fw_dump,
413 	.owner		=	THIS_MODULE,
414 };
415 
416 static int __init init_fw(void)
417 {
418 	return register_tcf_proto_ops(&cls_fw_ops);
419 }
420 
421 static void __exit exit_fw(void)
422 {
423 	unregister_tcf_proto_ops(&cls_fw_ops);
424 }
425 
426 module_init(init_fw)
427 module_exit(exit_fw)
428 MODULE_LICENSE("GPL");
429