xref: /openbmc/linux/net/sched/cls_fw.c (revision 799a545b) 
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 bool fw_destroy(struct tcf_proto *tp, bool force)
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 true;
138 
139 	if (!force) {
140 		for (h = 0; h < HTSIZE; h++)
141 			if (rcu_access_pointer(head->ht[h]))
142 				return false;
143 	}
144 
145 	for (h = 0; h < HTSIZE; h++) {
146 		while ((f = rtnl_dereference(head->ht[h])) != NULL) {
147 			RCU_INIT_POINTER(head->ht[h],
148 					 rtnl_dereference(f->next));
149 			tcf_unbind_filter(tp, &f->res);
150 			call_rcu(&f->rcu, fw_delete_filter);
151 		}
152 	}
153 	RCU_INIT_POINTER(tp->root, NULL);
154 	kfree_rcu(head, rcu);
155 	return true;
156 }
157 
158 static int fw_delete(struct tcf_proto *tp, unsigned long arg)
159 {
160 	struct fw_head *head = rtnl_dereference(tp->root);
161 	struct fw_filter *f = (struct fw_filter *)arg;
162 	struct fw_filter __rcu **fp;
163 	struct fw_filter *pfp;
164 
165 	if (head == NULL || f == NULL)
166 		goto out;
167 
168 	fp = &head->ht[fw_hash(f->id)];
169 
170 	for (pfp = rtnl_dereference(*fp); pfp;
171 	     fp = &pfp->next, pfp = rtnl_dereference(*fp)) {
172 		if (pfp == f) {
173 			RCU_INIT_POINTER(*fp, rtnl_dereference(f->next));
174 			tcf_unbind_filter(tp, &f->res);
175 			call_rcu(&f->rcu, fw_delete_filter);
176 			return 0;
177 		}
178 	}
179 out:
180 	return -EINVAL;
181 }
182 
183 static const struct nla_policy fw_policy[TCA_FW_MAX + 1] = {
184 	[TCA_FW_CLASSID]	= { .type = NLA_U32 },
185 	[TCA_FW_INDEV]		= { .type = NLA_STRING, .len = IFNAMSIZ },
186 	[TCA_FW_MASK]		= { .type = NLA_U32 },
187 };
188 
189 static int
190 fw_change_attrs(struct net *net, struct tcf_proto *tp, struct fw_filter *f,
191 	struct nlattr **tb, struct nlattr **tca, unsigned long base, bool ovr)
192 {
193 	struct fw_head *head = rtnl_dereference(tp->root);
194 	struct tcf_exts e;
195 	u32 mask;
196 	int err;
197 
198 	tcf_exts_init(&e, TCA_FW_ACT, TCA_FW_POLICE);
199 	err = tcf_exts_validate(net, tp, tb, tca[TCA_RATE], &e, ovr);
200 	if (err < 0)
201 		return err;
202 
203 	if (tb[TCA_FW_CLASSID]) {
204 		f->res.classid = nla_get_u32(tb[TCA_FW_CLASSID]);
205 		tcf_bind_filter(tp, &f->res, base);
206 	}
207 
208 #ifdef CONFIG_NET_CLS_IND
209 	if (tb[TCA_FW_INDEV]) {
210 		int ret;
211 		ret = tcf_change_indev(net, tb[TCA_FW_INDEV]);
212 		if (ret < 0) {
213 			err = ret;
214 			goto errout;
215 		}
216 		f->ifindex = ret;
217 	}
218 #endif /* CONFIG_NET_CLS_IND */
219 
220 	err = -EINVAL;
221 	if (tb[TCA_FW_MASK]) {
222 		mask = nla_get_u32(tb[TCA_FW_MASK]);
223 		if (mask != head->mask)
224 			goto errout;
225 	} else if (head->mask != 0xFFFFFFFF)
226 		goto errout;
227 
228 	tcf_exts_change(tp, &f->exts, &e);
229 
230 	return 0;
231 errout:
232 	tcf_exts_destroy(&e);
233 	return err;
234 }
235 
236 static int fw_change(struct net *net, struct sk_buff *in_skb,
237 		     struct tcf_proto *tp, unsigned long base,
238 		     u32 handle,
239 		     struct nlattr **tca,
240 		     unsigned long *arg, bool ovr)
241 {
242 	struct fw_head *head = rtnl_dereference(tp->root);
243 	struct fw_filter *f = (struct fw_filter *) *arg;
244 	struct nlattr *opt = tca[TCA_OPTIONS];
245 	struct nlattr *tb[TCA_FW_MAX + 1];
246 	int err;
247 
248 	if (!opt)
249 		return handle ? -EINVAL : 0; /* Succeed if it is old method. */
250 
251 	err = nla_parse_nested(tb, TCA_FW_MAX, opt, fw_policy);
252 	if (err < 0)
253 		return err;
254 
255 	if (f) {
256 		struct fw_filter *pfp, *fnew;
257 		struct fw_filter __rcu **fp;
258 
259 		if (f->id != handle && handle)
260 			return -EINVAL;
261 
262 		fnew = kzalloc(sizeof(struct fw_filter), GFP_KERNEL);
263 		if (!fnew)
264 			return -ENOBUFS;
265 
266 		fnew->id = f->id;
267 		fnew->res = f->res;
268 #ifdef CONFIG_NET_CLS_IND
269 		fnew->ifindex = f->ifindex;
270 #endif /* CONFIG_NET_CLS_IND */
271 		fnew->tp = f->tp;
272 
273 		tcf_exts_init(&fnew->exts, TCA_FW_ACT, TCA_FW_POLICE);
274 
275 		err = fw_change_attrs(net, tp, fnew, tb, tca, base, ovr);
276 		if (err < 0) {
277 			kfree(fnew);
278 			return err;
279 		}
280 
281 		fp = &head->ht[fw_hash(fnew->id)];
282 		for (pfp = rtnl_dereference(*fp); pfp;
283 		     fp = &pfp->next, pfp = rtnl_dereference(*fp))
284 			if (pfp == f)
285 				break;
286 
287 		RCU_INIT_POINTER(fnew->next, rtnl_dereference(pfp->next));
288 		rcu_assign_pointer(*fp, fnew);
289 		tcf_unbind_filter(tp, &f->res);
290 		call_rcu(&f->rcu, fw_delete_filter);
291 
292 		*arg = (unsigned long)fnew;
293 		return err;
294 	}
295 
296 	if (!handle)
297 		return -EINVAL;
298 
299 	if (!head) {
300 		u32 mask = 0xFFFFFFFF;
301 		if (tb[TCA_FW_MASK])
302 			mask = nla_get_u32(tb[TCA_FW_MASK]);
303 
304 		head = kzalloc(sizeof(*head), GFP_KERNEL);
305 		if (!head)
306 			return -ENOBUFS;
307 		head->mask = mask;
308 
309 		rcu_assign_pointer(tp->root, head);
310 	}
311 
312 	f = kzalloc(sizeof(struct fw_filter), GFP_KERNEL);
313 	if (f == NULL)
314 		return -ENOBUFS;
315 
316 	tcf_exts_init(&f->exts, TCA_FW_ACT, TCA_FW_POLICE);
317 	f->id = handle;
318 	f->tp = tp;
319 
320 	err = fw_change_attrs(net, tp, f, tb, tca, base, ovr);
321 	if (err < 0)
322 		goto errout;
323 
324 	RCU_INIT_POINTER(f->next, head->ht[fw_hash(handle)]);
325 	rcu_assign_pointer(head->ht[fw_hash(handle)], f);
326 
327 	*arg = (unsigned long)f;
328 	return 0;
329 
330 errout:
331 	kfree(f);
332 	return err;
333 }
334 
335 static void fw_walk(struct tcf_proto *tp, struct tcf_walker *arg)
336 {
337 	struct fw_head *head = rtnl_dereference(tp->root);
338 	int h;
339 
340 	if (head == NULL)
341 		arg->stop = 1;
342 
343 	if (arg->stop)
344 		return;
345 
346 	for (h = 0; h < HTSIZE; h++) {
347 		struct fw_filter *f;
348 
349 		for (f = rtnl_dereference(head->ht[h]); f;
350 		     f = rtnl_dereference(f->next)) {
351 			if (arg->count < arg->skip) {
352 				arg->count++;
353 				continue;
354 			}
355 			if (arg->fn(tp, (unsigned long)f, arg) < 0) {
356 				arg->stop = 1;
357 				return;
358 			}
359 			arg->count++;
360 		}
361 	}
362 }
363 
364 static int fw_dump(struct net *net, struct tcf_proto *tp, unsigned long fh,
365 		   struct sk_buff *skb, struct tcmsg *t)
366 {
367 	struct fw_head *head = rtnl_dereference(tp->root);
368 	struct fw_filter *f = (struct fw_filter *)fh;
369 	struct nlattr *nest;
370 
371 	if (f == NULL)
372 		return skb->len;
373 
374 	t->tcm_handle = f->id;
375 
376 	if (!f->res.classid && !tcf_exts_is_available(&f->exts))
377 		return skb->len;
378 
379 	nest = nla_nest_start(skb, TCA_OPTIONS);
380 	if (nest == NULL)
381 		goto nla_put_failure;
382 
383 	if (f->res.classid &&
384 	    nla_put_u32(skb, TCA_FW_CLASSID, f->res.classid))
385 		goto nla_put_failure;
386 #ifdef CONFIG_NET_CLS_IND
387 	if (f->ifindex) {
388 		struct net_device *dev;
389 		dev = __dev_get_by_index(net, f->ifindex);
390 		if (dev && nla_put_string(skb, TCA_FW_INDEV, dev->name))
391 			goto nla_put_failure;
392 	}
393 #endif /* CONFIG_NET_CLS_IND */
394 	if (head->mask != 0xFFFFFFFF &&
395 	    nla_put_u32(skb, TCA_FW_MASK, head->mask))
396 		goto nla_put_failure;
397 
398 	if (tcf_exts_dump(skb, &f->exts) < 0)
399 		goto nla_put_failure;
400 
401 	nla_nest_end(skb, nest);
402 
403 	if (tcf_exts_dump_stats(skb, &f->exts) < 0)
404 		goto nla_put_failure;
405 
406 	return skb->len;
407 
408 nla_put_failure:
409 	nla_nest_cancel(skb, nest);
410 	return -1;
411 }
412 
413 static struct tcf_proto_ops cls_fw_ops __read_mostly = {
414 	.kind		=	"fw",
415 	.classify	=	fw_classify,
416 	.init		=	fw_init,
417 	.destroy	=	fw_destroy,
418 	.get		=	fw_get,
419 	.change		=	fw_change,
420 	.delete		=	fw_delete,
421 	.walk		=	fw_walk,
422 	.dump		=	fw_dump,
423 	.owner		=	THIS_MODULE,
424 };
425 
426 static int __init init_fw(void)
427 {
428 	return register_tcf_proto_ops(&cls_fw_ops);
429 }
430 
431 static void __exit exit_fw(void)
432 {
433 	unregister_tcf_proto_ops(&cls_fw_ops);
434 }
435 
436 module_init(init_fw)
437 module_exit(exit_fw)
438 MODULE_LICENSE("GPL");
439