xref: /openbmc/linux/net/sched/cls_fw.c (revision b7019ac5) 
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * net/sched/cls_fw.c	Classifier mapping ipchains' fwmark to traffic class.
4  *
5  * Authors:	Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
6  *
7  * Changes:
8  * Karlis Peisenieks <karlis@mt.lv> : 990415 : fw_walk off by one
9  * Karlis Peisenieks <karlis@mt.lv> : 990415 : fw_delete killed all the filter (and kernel).
10  * Alex <alex@pilotsoft.com> : 2004xxyy: Added Action extension
11  *
12  * JHS: We should remove the CONFIG_NET_CLS_IND from here
13  * eventually when the meta match extension is made available
14  */
15 
16 #include <linux/module.h>
17 #include <linux/slab.h>
18 #include <linux/types.h>
19 #include <linux/kernel.h>
20 #include <linux/string.h>
21 #include <linux/errno.h>
22 #include <linux/skbuff.h>
23 #include <net/netlink.h>
24 #include <net/act_api.h>
25 #include <net/pkt_cls.h>
26 #include <net/sch_generic.h>
27 
28 #define HTSIZE 256
29 
30 struct fw_head {
31 	u32			mask;
32 	struct fw_filter __rcu	*ht[HTSIZE];
33 	struct rcu_head		rcu;
34 };
35 
36 struct fw_filter {
37 	struct fw_filter __rcu	*next;
38 	u32			id;
39 	struct tcf_result	res;
40 #ifdef CONFIG_NET_CLS_IND
41 	int			ifindex;
42 #endif /* CONFIG_NET_CLS_IND */
43 	struct tcf_exts		exts;
44 	struct tcf_proto	*tp;
45 	struct rcu_work		rwork;
46 };
47 
48 static u32 fw_hash(u32 handle)
49 {
50 	handle ^= (handle >> 16);
51 	handle ^= (handle >> 8);
52 	return handle % HTSIZE;
53 }
54 
55 static int fw_classify(struct sk_buff *skb, const struct tcf_proto *tp,
56 		       struct tcf_result *res)
57 {
58 	struct fw_head *head = rcu_dereference_bh(tp->root);
59 	struct fw_filter *f;
60 	int r;
61 	u32 id = skb->mark;
62 
63 	if (head != NULL) {
64 		id &= head->mask;
65 
66 		for (f = rcu_dereference_bh(head->ht[fw_hash(id)]); f;
67 		     f = rcu_dereference_bh(f->next)) {
68 			if (f->id == id) {
69 				*res = f->res;
70 #ifdef CONFIG_NET_CLS_IND
71 				if (!tcf_match_indev(skb, f->ifindex))
72 					continue;
73 #endif /* CONFIG_NET_CLS_IND */
74 				r = tcf_exts_exec(skb, &f->exts, res);
75 				if (r < 0)
76 					continue;
77 
78 				return r;
79 			}
80 		}
81 	} else {
82 		struct Qdisc *q = tcf_block_q(tp->chain->block);
83 
84 		/* Old method: classify the packet using its skb mark. */
85 		if (id && (TC_H_MAJ(id) == 0 ||
86 			   !(TC_H_MAJ(id ^ q->handle)))) {
87 			res->classid = id;
88 			res->class = 0;
89 			return 0;
90 		}
91 	}
92 
93 	return -1;
94 }
95 
96 static void *fw_get(struct tcf_proto *tp, u32 handle)
97 {
98 	struct fw_head *head = rtnl_dereference(tp->root);
99 	struct fw_filter *f;
100 
101 	if (head == NULL)
102 		return NULL;
103 
104 	f = rtnl_dereference(head->ht[fw_hash(handle)]);
105 	for (; f; f = rtnl_dereference(f->next)) {
106 		if (f->id == handle)
107 			return f;
108 	}
109 	return NULL;
110 }
111 
112 static int fw_init(struct tcf_proto *tp)
113 {
114 	/* We don't allocate fw_head here, because in the old method
115 	 * we don't need it at all.
116 	 */
117 	return 0;
118 }
119 
120 static void __fw_delete_filter(struct fw_filter *f)
121 {
122 	tcf_exts_destroy(&f->exts);
123 	tcf_exts_put_net(&f->exts);
124 	kfree(f);
125 }
126 
127 static void fw_delete_filter_work(struct work_struct *work)
128 {
129 	struct fw_filter *f = container_of(to_rcu_work(work),
130 					   struct fw_filter,
131 					   rwork);
132 	rtnl_lock();
133 	__fw_delete_filter(f);
134 	rtnl_unlock();
135 }
136 
137 static void fw_destroy(struct tcf_proto *tp, bool rtnl_held,
138 		       struct netlink_ext_ack *extack)
139 {
140 	struct fw_head *head = rtnl_dereference(tp->root);
141 	struct fw_filter *f;
142 	int h;
143 
144 	if (head == NULL)
145 		return;
146 
147 	for (h = 0; h < HTSIZE; h++) {
148 		while ((f = rtnl_dereference(head->ht[h])) != NULL) {
149 			RCU_INIT_POINTER(head->ht[h],
150 					 rtnl_dereference(f->next));
151 			tcf_unbind_filter(tp, &f->res);
152 			if (tcf_exts_get_net(&f->exts))
153 				tcf_queue_work(&f->rwork, fw_delete_filter_work);
154 			else
155 				__fw_delete_filter(f);
156 		}
157 	}
158 	kfree_rcu(head, rcu);
159 }
160 
161 static int fw_delete(struct tcf_proto *tp, void *arg, bool *last,
162 		     bool rtnl_held, struct netlink_ext_ack *extack)
163 {
164 	struct fw_head *head = rtnl_dereference(tp->root);
165 	struct fw_filter *f = arg;
166 	struct fw_filter __rcu **fp;
167 	struct fw_filter *pfp;
168 	int ret = -EINVAL;
169 	int h;
170 
171 	if (head == NULL || f == NULL)
172 		goto out;
173 
174 	fp = &head->ht[fw_hash(f->id)];
175 
176 	for (pfp = rtnl_dereference(*fp); pfp;
177 	     fp = &pfp->next, pfp = rtnl_dereference(*fp)) {
178 		if (pfp == f) {
179 			RCU_INIT_POINTER(*fp, rtnl_dereference(f->next));
180 			tcf_unbind_filter(tp, &f->res);
181 			tcf_exts_get_net(&f->exts);
182 			tcf_queue_work(&f->rwork, fw_delete_filter_work);
183 			ret = 0;
184 			break;
185 		}
186 	}
187 
188 	*last = true;
189 	for (h = 0; h < HTSIZE; h++) {
190 		if (rcu_access_pointer(head->ht[h])) {
191 			*last = false;
192 			break;
193 		}
194 	}
195 
196 out:
197 	return ret;
198 }
199 
200 static const struct nla_policy fw_policy[TCA_FW_MAX + 1] = {
201 	[TCA_FW_CLASSID]	= { .type = NLA_U32 },
202 	[TCA_FW_INDEV]		= { .type = NLA_STRING, .len = IFNAMSIZ },
203 	[TCA_FW_MASK]		= { .type = NLA_U32 },
204 };
205 
206 static int fw_set_parms(struct net *net, struct tcf_proto *tp,
207 			struct fw_filter *f, struct nlattr **tb,
208 			struct nlattr **tca, unsigned long base, bool ovr,
209 			struct netlink_ext_ack *extack)
210 {
211 	struct fw_head *head = rtnl_dereference(tp->root);
212 	u32 mask;
213 	int err;
214 
215 	err = tcf_exts_validate(net, tp, tb, tca[TCA_RATE], &f->exts, ovr,
216 				true, extack);
217 	if (err < 0)
218 		return err;
219 
220 	if (tb[TCA_FW_CLASSID]) {
221 		f->res.classid = nla_get_u32(tb[TCA_FW_CLASSID]);
222 		tcf_bind_filter(tp, &f->res, base);
223 	}
224 
225 #ifdef CONFIG_NET_CLS_IND
226 	if (tb[TCA_FW_INDEV]) {
227 		int ret;
228 		ret = tcf_change_indev(net, tb[TCA_FW_INDEV], extack);
229 		if (ret < 0)
230 			return ret;
231 		f->ifindex = ret;
232 	}
233 #endif /* CONFIG_NET_CLS_IND */
234 
235 	err = -EINVAL;
236 	if (tb[TCA_FW_MASK]) {
237 		mask = nla_get_u32(tb[TCA_FW_MASK]);
238 		if (mask != head->mask)
239 			return err;
240 	} else if (head->mask != 0xFFFFFFFF)
241 		return err;
242 
243 	return 0;
244 }
245 
246 static int fw_change(struct net *net, struct sk_buff *in_skb,
247 		     struct tcf_proto *tp, unsigned long base,
248 		     u32 handle, struct nlattr **tca, void **arg,
249 		     bool ovr, bool rtnl_held,
250 		     struct netlink_ext_ack *extack)
251 {
252 	struct fw_head *head = rtnl_dereference(tp->root);
253 	struct fw_filter *f = *arg;
254 	struct nlattr *opt = tca[TCA_OPTIONS];
255 	struct nlattr *tb[TCA_FW_MAX + 1];
256 	int err;
257 
258 	if (!opt)
259 		return handle ? -EINVAL : 0; /* Succeed if it is old method. */
260 
261 	err = nla_parse_nested_deprecated(tb, TCA_FW_MAX, opt, fw_policy,
262 					  NULL);
263 	if (err < 0)
264 		return err;
265 
266 	if (f) {
267 		struct fw_filter *pfp, *fnew;
268 		struct fw_filter __rcu **fp;
269 
270 		if (f->id != handle && handle)
271 			return -EINVAL;
272 
273 		fnew = kzalloc(sizeof(struct fw_filter), GFP_KERNEL);
274 		if (!fnew)
275 			return -ENOBUFS;
276 
277 		fnew->id = f->id;
278 		fnew->res = f->res;
279 #ifdef CONFIG_NET_CLS_IND
280 		fnew->ifindex = f->ifindex;
281 #endif /* CONFIG_NET_CLS_IND */
282 		fnew->tp = f->tp;
283 
284 		err = tcf_exts_init(&fnew->exts, net, TCA_FW_ACT,
285 				    TCA_FW_POLICE);
286 		if (err < 0) {
287 			kfree(fnew);
288 			return err;
289 		}
290 
291 		err = fw_set_parms(net, tp, fnew, tb, tca, base, ovr, extack);
292 		if (err < 0) {
293 			tcf_exts_destroy(&fnew->exts);
294 			kfree(fnew);
295 			return err;
296 		}
297 
298 		fp = &head->ht[fw_hash(fnew->id)];
299 		for (pfp = rtnl_dereference(*fp); pfp;
300 		     fp = &pfp->next, pfp = rtnl_dereference(*fp))
301 			if (pfp == f)
302 				break;
303 
304 		RCU_INIT_POINTER(fnew->next, rtnl_dereference(pfp->next));
305 		rcu_assign_pointer(*fp, fnew);
306 		tcf_unbind_filter(tp, &f->res);
307 		tcf_exts_get_net(&f->exts);
308 		tcf_queue_work(&f->rwork, fw_delete_filter_work);
309 
310 		*arg = fnew;
311 		return err;
312 	}
313 
314 	if (!handle)
315 		return -EINVAL;
316 
317 	if (!head) {
318 		u32 mask = 0xFFFFFFFF;
319 		if (tb[TCA_FW_MASK])
320 			mask = nla_get_u32(tb[TCA_FW_MASK]);
321 
322 		head = kzalloc(sizeof(*head), GFP_KERNEL);
323 		if (!head)
324 			return -ENOBUFS;
325 		head->mask = mask;
326 
327 		rcu_assign_pointer(tp->root, head);
328 	}
329 
330 	f = kzalloc(sizeof(struct fw_filter), GFP_KERNEL);
331 	if (f == NULL)
332 		return -ENOBUFS;
333 
334 	err = tcf_exts_init(&f->exts, net, TCA_FW_ACT, TCA_FW_POLICE);
335 	if (err < 0)
336 		goto errout;
337 	f->id = handle;
338 	f->tp = tp;
339 
340 	err = fw_set_parms(net, tp, f, tb, tca, base, ovr, extack);
341 	if (err < 0)
342 		goto errout;
343 
344 	RCU_INIT_POINTER(f->next, head->ht[fw_hash(handle)]);
345 	rcu_assign_pointer(head->ht[fw_hash(handle)], f);
346 
347 	*arg = f;
348 	return 0;
349 
350 errout:
351 	tcf_exts_destroy(&f->exts);
352 	kfree(f);
353 	return err;
354 }
355 
356 static void fw_walk(struct tcf_proto *tp, struct tcf_walker *arg,
357 		    bool rtnl_held)
358 {
359 	struct fw_head *head = rtnl_dereference(tp->root);
360 	int h;
361 
362 	if (head == NULL)
363 		arg->stop = 1;
364 
365 	if (arg->stop)
366 		return;
367 
368 	for (h = 0; h < HTSIZE; h++) {
369 		struct fw_filter *f;
370 
371 		for (f = rtnl_dereference(head->ht[h]); f;
372 		     f = rtnl_dereference(f->next)) {
373 			if (arg->count < arg->skip) {
374 				arg->count++;
375 				continue;
376 			}
377 			if (arg->fn(tp, f, arg) < 0) {
378 				arg->stop = 1;
379 				return;
380 			}
381 			arg->count++;
382 		}
383 	}
384 }
385 
386 static int fw_dump(struct net *net, struct tcf_proto *tp, void *fh,
387 		   struct sk_buff *skb, struct tcmsg *t, bool rtnl_held)
388 {
389 	struct fw_head *head = rtnl_dereference(tp->root);
390 	struct fw_filter *f = fh;
391 	struct nlattr *nest;
392 
393 	if (f == NULL)
394 		return skb->len;
395 
396 	t->tcm_handle = f->id;
397 
398 	if (!f->res.classid && !tcf_exts_has_actions(&f->exts))
399 		return skb->len;
400 
401 	nest = nla_nest_start_noflag(skb, TCA_OPTIONS);
402 	if (nest == NULL)
403 		goto nla_put_failure;
404 
405 	if (f->res.classid &&
406 	    nla_put_u32(skb, TCA_FW_CLASSID, f->res.classid))
407 		goto nla_put_failure;
408 #ifdef CONFIG_NET_CLS_IND
409 	if (f->ifindex) {
410 		struct net_device *dev;
411 		dev = __dev_get_by_index(net, f->ifindex);
412 		if (dev && nla_put_string(skb, TCA_FW_INDEV, dev->name))
413 			goto nla_put_failure;
414 	}
415 #endif /* CONFIG_NET_CLS_IND */
416 	if (head->mask != 0xFFFFFFFF &&
417 	    nla_put_u32(skb, TCA_FW_MASK, head->mask))
418 		goto nla_put_failure;
419 
420 	if (tcf_exts_dump(skb, &f->exts) < 0)
421 		goto nla_put_failure;
422 
423 	nla_nest_end(skb, nest);
424 
425 	if (tcf_exts_dump_stats(skb, &f->exts) < 0)
426 		goto nla_put_failure;
427 
428 	return skb->len;
429 
430 nla_put_failure:
431 	nla_nest_cancel(skb, nest);
432 	return -1;
433 }
434 
435 static void fw_bind_class(void *fh, u32 classid, unsigned long cl)
436 {
437 	struct fw_filter *f = fh;
438 
439 	if (f && f->res.classid == classid)
440 		f->res.class = cl;
441 }
442 
443 static struct tcf_proto_ops cls_fw_ops __read_mostly = {
444 	.kind		=	"fw",
445 	.classify	=	fw_classify,
446 	.init		=	fw_init,
447 	.destroy	=	fw_destroy,
448 	.get		=	fw_get,
449 	.change		=	fw_change,
450 	.delete		=	fw_delete,
451 	.walk		=	fw_walk,
452 	.dump		=	fw_dump,
453 	.bind_class	=	fw_bind_class,
454 	.owner		=	THIS_MODULE,
455 };
456 
457 static int __init init_fw(void)
458 {
459 	return register_tcf_proto_ops(&cls_fw_ops);
460 }
461 
462 static void __exit exit_fw(void)
463 {
464 	unregister_tcf_proto_ops(&cls_fw_ops);
465 }
466 
467 module_init(init_fw)
468 module_exit(exit_fw)
469 MODULE_LICENSE("GPL");
470