xref: /linux/net/sched/cls_fw.c (revision d642ef71) 
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 
13 #include <linux/module.h>
14 #include <linux/slab.h>
15 #include <linux/types.h>
16 #include <linux/kernel.h>
17 #include <linux/string.h>
18 #include <linux/errno.h>
19 #include <linux/skbuff.h>
20 #include <net/netlink.h>
21 #include <net/act_api.h>
22 #include <net/pkt_cls.h>
23 #include <net/sch_generic.h>
24 #include <net/tc_wrapper.h>
25 
26 #define HTSIZE 256
27 
28 struct fw_head {
29 	u32			mask;
30 	struct fw_filter __rcu	*ht[HTSIZE];
31 	struct rcu_head		rcu;
32 };
33 
34 struct fw_filter {
35 	struct fw_filter __rcu	*next;
36 	u32			id;
37 	struct tcf_result	res;
38 	int			ifindex;
39 	struct tcf_exts		exts;
40 	struct tcf_proto	*tp;
41 	struct rcu_work		rwork;
42 };
43 
44 static u32 fw_hash(u32 handle)
45 {
46 	handle ^= (handle >> 16);
47 	handle ^= (handle >> 8);
48 	return handle % HTSIZE;
49 }
50 
51 TC_INDIRECT_SCOPE int fw_classify(struct sk_buff *skb,
52 				  const struct tcf_proto *tp,
53 				  struct tcf_result *res)
54 {
55 	struct fw_head *head = rcu_dereference_bh(tp->root);
56 	struct fw_filter *f;
57 	int r;
58 	u32 id = skb->mark;
59 
60 	if (head != NULL) {
61 		id &= head->mask;
62 
63 		for (f = rcu_dereference_bh(head->ht[fw_hash(id)]); f;
64 		     f = rcu_dereference_bh(f->next)) {
65 			if (f->id == id) {
66 				*res = f->res;
67 				if (!tcf_match_indev(skb, f->ifindex))
68 					continue;
69 				r = tcf_exts_exec(skb, &f->exts, res);
70 				if (r < 0)
71 					continue;
72 
73 				return r;
74 			}
75 		}
76 	} else {
77 		struct Qdisc *q = tcf_block_q(tp->chain->block);
78 
79 		/* Old method: classify the packet using its skb mark. */
80 		if (id && (TC_H_MAJ(id) == 0 ||
81 			   !(TC_H_MAJ(id ^ q->handle)))) {
82 			res->classid = id;
83 			res->class = 0;
84 			return 0;
85 		}
86 	}
87 
88 	return -1;
89 }
90 
91 static void *fw_get(struct tcf_proto *tp, u32 handle)
92 {
93 	struct fw_head *head = rtnl_dereference(tp->root);
94 	struct fw_filter *f;
95 
96 	if (head == NULL)
97 		return NULL;
98 
99 	f = rtnl_dereference(head->ht[fw_hash(handle)]);
100 	for (; f; f = rtnl_dereference(f->next)) {
101 		if (f->id == handle)
102 			return f;
103 	}
104 	return NULL;
105 }
106 
107 static int fw_init(struct tcf_proto *tp)
108 {
109 	/* We don't allocate fw_head here, because in the old method
110 	 * we don't need it at all.
111 	 */
112 	return 0;
113 }
114 
115 static void __fw_delete_filter(struct fw_filter *f)
116 {
117 	tcf_exts_destroy(&f->exts);
118 	tcf_exts_put_net(&f->exts);
119 	kfree(f);
120 }
121 
122 static void fw_delete_filter_work(struct work_struct *work)
123 {
124 	struct fw_filter *f = container_of(to_rcu_work(work),
125 					   struct fw_filter,
126 					   rwork);
127 	rtnl_lock();
128 	__fw_delete_filter(f);
129 	rtnl_unlock();
130 }
131 
132 static void fw_destroy(struct tcf_proto *tp, bool rtnl_held,
133 		       struct netlink_ext_ack *extack)
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 			if (tcf_exts_get_net(&f->exts))
148 				tcf_queue_work(&f->rwork, fw_delete_filter_work);
149 			else
150 				__fw_delete_filter(f);
151 		}
152 	}
153 	kfree_rcu(head, rcu);
154 }
155 
156 static int fw_delete(struct tcf_proto *tp, void *arg, bool *last,
157 		     bool rtnl_held, struct netlink_ext_ack *extack)
158 {
159 	struct fw_head *head = rtnl_dereference(tp->root);
160 	struct fw_filter *f = arg;
161 	struct fw_filter __rcu **fp;
162 	struct fw_filter *pfp;
163 	int ret = -EINVAL;
164 	int h;
165 
166 	if (head == NULL || f == NULL)
167 		goto out;
168 
169 	fp = &head->ht[fw_hash(f->id)];
170 
171 	for (pfp = rtnl_dereference(*fp); pfp;
172 	     fp = &pfp->next, pfp = rtnl_dereference(*fp)) {
173 		if (pfp == f) {
174 			RCU_INIT_POINTER(*fp, rtnl_dereference(f->next));
175 			tcf_unbind_filter(tp, &f->res);
176 			tcf_exts_get_net(&f->exts);
177 			tcf_queue_work(&f->rwork, fw_delete_filter_work);
178 			ret = 0;
179 			break;
180 		}
181 	}
182 
183 	*last = true;
184 	for (h = 0; h < HTSIZE; h++) {
185 		if (rcu_access_pointer(head->ht[h])) {
186 			*last = false;
187 			break;
188 		}
189 	}
190 
191 out:
192 	return ret;
193 }
194 
195 static const struct nla_policy fw_policy[TCA_FW_MAX + 1] = {
196 	[TCA_FW_CLASSID]	= { .type = NLA_U32 },
197 	[TCA_FW_INDEV]		= { .type = NLA_STRING, .len = IFNAMSIZ },
198 	[TCA_FW_MASK]		= { .type = NLA_U32 },
199 };
200 
201 static int fw_set_parms(struct net *net, struct tcf_proto *tp,
202 			struct fw_filter *f, struct nlattr **tb,
203 			struct nlattr **tca, unsigned long base, u32 flags,
204 			struct netlink_ext_ack *extack)
205 {
206 	struct fw_head *head = rtnl_dereference(tp->root);
207 	u32 mask;
208 	int err;
209 
210 	err = tcf_exts_validate(net, tp, tb, tca[TCA_RATE], &f->exts, flags,
211 				extack);
212 	if (err < 0)
213 		return err;
214 
215 	if (tb[TCA_FW_INDEV]) {
216 		int ret;
217 		ret = tcf_change_indev(net, tb[TCA_FW_INDEV], extack);
218 		if (ret < 0)
219 			return ret;
220 		f->ifindex = ret;
221 	}
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 	if (tb[TCA_FW_CLASSID]) {
232 		f->res.classid = nla_get_u32(tb[TCA_FW_CLASSID]);
233 		tcf_bind_filter(tp, &f->res, base);
234 	}
235 
236 	return 0;
237 }
238 
239 static int fw_change(struct net *net, struct sk_buff *in_skb,
240 		     struct tcf_proto *tp, unsigned long base,
241 		     u32 handle, struct nlattr **tca, void **arg,
242 		     u32 flags, struct netlink_ext_ack *extack)
243 {
244 	struct fw_head *head = rtnl_dereference(tp->root);
245 	struct fw_filter *f = *arg;
246 	struct nlattr *opt = tca[TCA_OPTIONS];
247 	struct nlattr *tb[TCA_FW_MAX + 1];
248 	int err;
249 
250 	if (!opt)
251 		return handle ? -EINVAL : 0; /* Succeed if it is old method. */
252 
253 	err = nla_parse_nested_deprecated(tb, TCA_FW_MAX, opt, fw_policy,
254 					  NULL);
255 	if (err < 0)
256 		return err;
257 
258 	if (f) {
259 		struct fw_filter *pfp, *fnew;
260 		struct fw_filter __rcu **fp;
261 
262 		if (f->id != handle && handle)
263 			return -EINVAL;
264 
265 		fnew = kzalloc(sizeof(struct fw_filter), GFP_KERNEL);
266 		if (!fnew)
267 			return -ENOBUFS;
268 
269 		fnew->id = f->id;
270 		fnew->ifindex = f->ifindex;
271 		fnew->tp = f->tp;
272 
273 		err = tcf_exts_init(&fnew->exts, net, TCA_FW_ACT,
274 				    TCA_FW_POLICE);
275 		if (err < 0) {
276 			kfree(fnew);
277 			return err;
278 		}
279 
280 		err = fw_set_parms(net, tp, fnew, tb, tca, base, flags, extack);
281 		if (err < 0) {
282 			tcf_exts_destroy(&fnew->exts);
283 			kfree(fnew);
284 			return err;
285 		}
286 
287 		fp = &head->ht[fw_hash(fnew->id)];
288 		for (pfp = rtnl_dereference(*fp); pfp;
289 		     fp = &pfp->next, pfp = rtnl_dereference(*fp))
290 			if (pfp == f)
291 				break;
292 
293 		RCU_INIT_POINTER(fnew->next, rtnl_dereference(pfp->next));
294 		rcu_assign_pointer(*fp, fnew);
295 		tcf_unbind_filter(tp, &f->res);
296 		tcf_exts_get_net(&f->exts);
297 		tcf_queue_work(&f->rwork, fw_delete_filter_work);
298 
299 		*arg = fnew;
300 		return err;
301 	}
302 
303 	if (!handle)
304 		return -EINVAL;
305 
306 	if (!head) {
307 		u32 mask = 0xFFFFFFFF;
308 		if (tb[TCA_FW_MASK])
309 			mask = nla_get_u32(tb[TCA_FW_MASK]);
310 
311 		head = kzalloc(sizeof(*head), GFP_KERNEL);
312 		if (!head)
313 			return -ENOBUFS;
314 		head->mask = mask;
315 
316 		rcu_assign_pointer(tp->root, head);
317 	}
318 
319 	f = kzalloc(sizeof(struct fw_filter), GFP_KERNEL);
320 	if (f == NULL)
321 		return -ENOBUFS;
322 
323 	err = tcf_exts_init(&f->exts, net, TCA_FW_ACT, TCA_FW_POLICE);
324 	if (err < 0)
325 		goto errout;
326 	f->id = handle;
327 	f->tp = tp;
328 
329 	err = fw_set_parms(net, tp, f, tb, tca, base, flags, extack);
330 	if (err < 0)
331 		goto errout;
332 
333 	RCU_INIT_POINTER(f->next, head->ht[fw_hash(handle)]);
334 	rcu_assign_pointer(head->ht[fw_hash(handle)], f);
335 
336 	*arg = f;
337 	return 0;
338 
339 errout:
340 	tcf_exts_destroy(&f->exts);
341 	kfree(f);
342 	return err;
343 }
344 
345 static void fw_walk(struct tcf_proto *tp, struct tcf_walker *arg,
346 		    bool rtnl_held)
347 {
348 	struct fw_head *head = rtnl_dereference(tp->root);
349 	int h;
350 
351 	if (head == NULL)
352 		arg->stop = 1;
353 
354 	if (arg->stop)
355 		return;
356 
357 	for (h = 0; h < HTSIZE; h++) {
358 		struct fw_filter *f;
359 
360 		for (f = rtnl_dereference(head->ht[h]); f;
361 		     f = rtnl_dereference(f->next)) {
362 			if (!tc_cls_stats_dump(tp, arg, f))
363 				return;
364 		}
365 	}
366 }
367 
368 static int fw_dump(struct net *net, struct tcf_proto *tp, void *fh,
369 		   struct sk_buff *skb, struct tcmsg *t, bool rtnl_held)
370 {
371 	struct fw_head *head = rtnl_dereference(tp->root);
372 	struct fw_filter *f = fh;
373 	struct nlattr *nest;
374 
375 	if (f == NULL)
376 		return skb->len;
377 
378 	t->tcm_handle = f->id;
379 
380 	if (!f->res.classid && !tcf_exts_has_actions(&f->exts))
381 		return skb->len;
382 
383 	nest = nla_nest_start_noflag(skb, TCA_OPTIONS);
384 	if (nest == NULL)
385 		goto nla_put_failure;
386 
387 	if (f->res.classid &&
388 	    nla_put_u32(skb, TCA_FW_CLASSID, f->res.classid))
389 		goto nla_put_failure;
390 	if (f->ifindex) {
391 		struct net_device *dev;
392 		dev = __dev_get_by_index(net, f->ifindex);
393 		if (dev && nla_put_string(skb, TCA_FW_INDEV, dev->name))
394 			goto nla_put_failure;
395 	}
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, void *q,
416 			  unsigned long base)
417 {
418 	struct fw_filter *f = fh;
419 
420 	tc_cls_bind_class(classid, cl, q, &f->res, base);
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_DESCRIPTION("SKB mark based TC classifier");
450 MODULE_LICENSE("GPL");
451