xref: /openbmc/linux/net/sched/cls_fw.c (revision 6aa7de05) 
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 void *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 NULL;
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 f;
110 	}
111 	return NULL;
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, void *arg, bool *last)
151 {
152 	struct fw_head *head = rtnl_dereference(tp->root);
153 	struct fw_filter *f = 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 fw_set_parms(struct net *net, struct tcf_proto *tp,
194 			struct fw_filter *f, struct nlattr **tb,
195 			struct nlattr **tca, unsigned long base, bool ovr)
196 {
197 	struct fw_head *head = rtnl_dereference(tp->root);
198 	u32 mask;
199 	int err;
200 
201 	err = tcf_exts_validate(net, tp, tb, tca[TCA_RATE], &f->exts, ovr);
202 	if (err < 0)
203 		return err;
204 
205 	if (tb[TCA_FW_CLASSID]) {
206 		f->res.classid = nla_get_u32(tb[TCA_FW_CLASSID]);
207 		tcf_bind_filter(tp, &f->res, base);
208 	}
209 
210 #ifdef CONFIG_NET_CLS_IND
211 	if (tb[TCA_FW_INDEV]) {
212 		int ret;
213 		ret = tcf_change_indev(net, tb[TCA_FW_INDEV]);
214 		if (ret < 0)
215 			return ret;
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 			return err;
225 	} else if (head->mask != 0xFFFFFFFF)
226 		return err;
227 
228 	return 0;
229 }
230 
231 static int fw_change(struct net *net, struct sk_buff *in_skb,
232 		     struct tcf_proto *tp, unsigned long base,
233 		     u32 handle, struct nlattr **tca, void **arg,
234 		     bool ovr)
235 {
236 	struct fw_head *head = rtnl_dereference(tp->root);
237 	struct fw_filter *f = *arg;
238 	struct nlattr *opt = tca[TCA_OPTIONS];
239 	struct nlattr *tb[TCA_FW_MAX + 1];
240 	int err;
241 
242 	if (!opt)
243 		return handle ? -EINVAL : 0; /* Succeed if it is old method. */
244 
245 	err = nla_parse_nested(tb, TCA_FW_MAX, opt, fw_policy, NULL);
246 	if (err < 0)
247 		return err;
248 
249 	if (f) {
250 		struct fw_filter *pfp, *fnew;
251 		struct fw_filter __rcu **fp;
252 
253 		if (f->id != handle && handle)
254 			return -EINVAL;
255 
256 		fnew = kzalloc(sizeof(struct fw_filter), GFP_KERNEL);
257 		if (!fnew)
258 			return -ENOBUFS;
259 
260 		fnew->id = f->id;
261 		fnew->res = f->res;
262 #ifdef CONFIG_NET_CLS_IND
263 		fnew->ifindex = f->ifindex;
264 #endif /* CONFIG_NET_CLS_IND */
265 		fnew->tp = f->tp;
266 
267 		err = tcf_exts_init(&fnew->exts, TCA_FW_ACT, TCA_FW_POLICE);
268 		if (err < 0) {
269 			kfree(fnew);
270 			return err;
271 		}
272 
273 		err = fw_set_parms(net, tp, fnew, tb, tca, base, ovr);
274 		if (err < 0) {
275 			tcf_exts_destroy(&fnew->exts);
276 			kfree(fnew);
277 			return err;
278 		}
279 
280 		fp = &head->ht[fw_hash(fnew->id)];
281 		for (pfp = rtnl_dereference(*fp); pfp;
282 		     fp = &pfp->next, pfp = rtnl_dereference(*fp))
283 			if (pfp == f)
284 				break;
285 
286 		RCU_INIT_POINTER(fnew->next, rtnl_dereference(pfp->next));
287 		rcu_assign_pointer(*fp, fnew);
288 		tcf_unbind_filter(tp, &f->res);
289 		call_rcu(&f->rcu, fw_delete_filter);
290 
291 		*arg = fnew;
292 		return err;
293 	}
294 
295 	if (!handle)
296 		return -EINVAL;
297 
298 	if (!head) {
299 		u32 mask = 0xFFFFFFFF;
300 		if (tb[TCA_FW_MASK])
301 			mask = nla_get_u32(tb[TCA_FW_MASK]);
302 
303 		head = kzalloc(sizeof(*head), GFP_KERNEL);
304 		if (!head)
305 			return -ENOBUFS;
306 		head->mask = mask;
307 
308 		rcu_assign_pointer(tp->root, head);
309 	}
310 
311 	f = kzalloc(sizeof(struct fw_filter), GFP_KERNEL);
312 	if (f == NULL)
313 		return -ENOBUFS;
314 
315 	err = tcf_exts_init(&f->exts, TCA_FW_ACT, TCA_FW_POLICE);
316 	if (err < 0)
317 		goto errout;
318 	f->id = handle;
319 	f->tp = tp;
320 
321 	err = fw_set_parms(net, tp, f, tb, tca, base, ovr);
322 	if (err < 0)
323 		goto errout;
324 
325 	RCU_INIT_POINTER(f->next, head->ht[fw_hash(handle)]);
326 	rcu_assign_pointer(head->ht[fw_hash(handle)], f);
327 
328 	*arg = f;
329 	return 0;
330 
331 errout:
332 	tcf_exts_destroy(&f->exts);
333 	kfree(f);
334 	return err;
335 }
336 
337 static void fw_walk(struct tcf_proto *tp, struct tcf_walker *arg)
338 {
339 	struct fw_head *head = rtnl_dereference(tp->root);
340 	int h;
341 
342 	if (head == NULL)
343 		arg->stop = 1;
344 
345 	if (arg->stop)
346 		return;
347 
348 	for (h = 0; h < HTSIZE; h++) {
349 		struct fw_filter *f;
350 
351 		for (f = rtnl_dereference(head->ht[h]); f;
352 		     f = rtnl_dereference(f->next)) {
353 			if (arg->count < arg->skip) {
354 				arg->count++;
355 				continue;
356 			}
357 			if (arg->fn(tp, f, arg) < 0) {
358 				arg->stop = 1;
359 				return;
360 			}
361 			arg->count++;
362 		}
363 	}
364 }
365 
366 static int fw_dump(struct net *net, struct tcf_proto *tp, void *fh,
367 		   struct sk_buff *skb, struct tcmsg *t)
368 {
369 	struct fw_head *head = rtnl_dereference(tp->root);
370 	struct fw_filter *f = fh;
371 	struct nlattr *nest;
372 
373 	if (f == NULL)
374 		return skb->len;
375 
376 	t->tcm_handle = f->id;
377 
378 	if (!f->res.classid && !tcf_exts_has_actions(&f->exts))
379 		return skb->len;
380 
381 	nest = nla_nest_start(skb, TCA_OPTIONS);
382 	if (nest == NULL)
383 		goto nla_put_failure;
384 
385 	if (f->res.classid &&
386 	    nla_put_u32(skb, TCA_FW_CLASSID, f->res.classid))
387 		goto nla_put_failure;
388 #ifdef CONFIG_NET_CLS_IND
389 	if (f->ifindex) {
390 		struct net_device *dev;
391 		dev = __dev_get_by_index(net, f->ifindex);
392 		if (dev && nla_put_string(skb, TCA_FW_INDEV, dev->name))
393 			goto nla_put_failure;
394 	}
395 #endif /* CONFIG_NET_CLS_IND */
396 	if (head->mask != 0xFFFFFFFF &&
397 	    nla_put_u32(skb, TCA_FW_MASK, head->mask))
398 		goto nla_put_failure;
399 
400 	if (tcf_exts_dump(skb, &f->exts) < 0)
401 		goto nla_put_failure;
402 
403 	nla_nest_end(skb, nest);
404 
405 	if (tcf_exts_dump_stats(skb, &f->exts) < 0)
406 		goto nla_put_failure;
407 
408 	return skb->len;
409 
410 nla_put_failure:
411 	nla_nest_cancel(skb, nest);
412 	return -1;
413 }
414 
415 static void fw_bind_class(void *fh, u32 classid, unsigned long cl)
416 {
417 	struct fw_filter *f = fh;
418 
419 	if (f && f->res.classid == classid)
420 		f->res.class = cl;
421 }
422 
423 static struct tcf_proto_ops cls_fw_ops __read_mostly = {
424 	.kind		=	"fw",
425 	.classify	=	fw_classify,
426 	.init		=	fw_init,
427 	.destroy	=	fw_destroy,
428 	.get		=	fw_get,
429 	.change		=	fw_change,
430 	.delete		=	fw_delete,
431 	.walk		=	fw_walk,
432 	.dump		=	fw_dump,
433 	.bind_class	=	fw_bind_class,
434 	.owner		=	THIS_MODULE,
435 };
436 
437 static int __init init_fw(void)
438 {
439 	return register_tcf_proto_ops(&cls_fw_ops);
440 }
441 
442 static void __exit exit_fw(void)
443 {
444 	unregister_tcf_proto_ops(&cls_fw_ops);
445 }
446 
447 module_init(init_fw)
448 module_exit(exit_fw)
449 MODULE_LICENSE("GPL");
450