xref: /linux/net/sched/cls_fw.c (revision 87c9c16317882dd6dbbc07e349bc3223e14f3244) 
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 
25 #define HTSIZE 256
26 
27 struct fw_head {
28 	u32			mask;
29 	struct fw_filter __rcu	*ht[HTSIZE];
30 	struct rcu_head		rcu;
31 };
32 
33 struct fw_filter {
34 	struct fw_filter __rcu	*next;
35 	u32			id;
36 	struct tcf_result	res;
37 	int			ifindex;
38 	struct tcf_exts		exts;
39 	struct tcf_proto	*tp;
40 	struct rcu_work		rwork;
41 };
42 
43 static u32 fw_hash(u32 handle)
44 {
45 	handle ^= (handle >> 16);
46 	handle ^= (handle >> 8);
47 	return handle % HTSIZE;
48 }
49 
50 static int fw_classify(struct sk_buff *skb, const struct tcf_proto *tp,
51 		       struct tcf_result *res)
52 {
53 	struct fw_head *head = rcu_dereference_bh(tp->root);
54 	struct fw_filter *f;
55 	int r;
56 	u32 id = skb->mark;
57 
58 	if (head != NULL) {
59 		id &= head->mask;
60 
61 		for (f = rcu_dereference_bh(head->ht[fw_hash(id)]); f;
62 		     f = rcu_dereference_bh(f->next)) {
63 			if (f->id == id) {
64 				*res = f->res;
65 				if (!tcf_match_indev(skb, f->ifindex))
66 					continue;
67 				r = tcf_exts_exec(skb, &f->exts, res);
68 				if (r < 0)
69 					continue;
70 
71 				return r;
72 			}
73 		}
74 	} else {
75 		struct Qdisc *q = tcf_block_q(tp->chain->block);
76 
77 		/* Old method: classify the packet using its skb mark. */
78 		if (id && (TC_H_MAJ(id) == 0 ||
79 			   !(TC_H_MAJ(id ^ q->handle)))) {
80 			res->classid = id;
81 			res->class = 0;
82 			return 0;
83 		}
84 	}
85 
86 	return -1;
87 }
88 
89 static void *fw_get(struct tcf_proto *tp, u32 handle)
90 {
91 	struct fw_head *head = rtnl_dereference(tp->root);
92 	struct fw_filter *f;
93 
94 	if (head == NULL)
95 		return NULL;
96 
97 	f = rtnl_dereference(head->ht[fw_hash(handle)]);
98 	for (; f; f = rtnl_dereference(f->next)) {
99 		if (f->id == handle)
100 			return f;
101 	}
102 	return NULL;
103 }
104 
105 static int fw_init(struct tcf_proto *tp)
106 {
107 	/* We don't allocate fw_head here, because in the old method
108 	 * we don't need it at all.
109 	 */
110 	return 0;
111 }
112 
113 static void __fw_delete_filter(struct fw_filter *f)
114 {
115 	tcf_exts_destroy(&f->exts);
116 	tcf_exts_put_net(&f->exts);
117 	kfree(f);
118 }
119 
120 static void fw_delete_filter_work(struct work_struct *work)
121 {
122 	struct fw_filter *f = container_of(to_rcu_work(work),
123 					   struct fw_filter,
124 					   rwork);
125 	rtnl_lock();
126 	__fw_delete_filter(f);
127 	rtnl_unlock();
128 }
129 
130 static void fw_destroy(struct tcf_proto *tp, bool rtnl_held,
131 		       struct netlink_ext_ack *extack)
132 {
133 	struct fw_head *head = rtnl_dereference(tp->root);
134 	struct fw_filter *f;
135 	int h;
136 
137 	if (head == NULL)
138 		return;
139 
140 	for (h = 0; h < HTSIZE; h++) {
141 		while ((f = rtnl_dereference(head->ht[h])) != NULL) {
142 			RCU_INIT_POINTER(head->ht[h],
143 					 rtnl_dereference(f->next));
144 			tcf_unbind_filter(tp, &f->res);
145 			if (tcf_exts_get_net(&f->exts))
146 				tcf_queue_work(&f->rwork, fw_delete_filter_work);
147 			else
148 				__fw_delete_filter(f);
149 		}
150 	}
151 	kfree_rcu(head, rcu);
152 }
153 
154 static int fw_delete(struct tcf_proto *tp, void *arg, bool *last,
155 		     bool rtnl_held, struct netlink_ext_ack *extack)
156 {
157 	struct fw_head *head = rtnl_dereference(tp->root);
158 	struct fw_filter *f = arg;
159 	struct fw_filter __rcu **fp;
160 	struct fw_filter *pfp;
161 	int ret = -EINVAL;
162 	int h;
163 
164 	if (head == NULL || f == NULL)
165 		goto out;
166 
167 	fp = &head->ht[fw_hash(f->id)];
168 
169 	for (pfp = rtnl_dereference(*fp); pfp;
170 	     fp = &pfp->next, pfp = rtnl_dereference(*fp)) {
171 		if (pfp == f) {
172 			RCU_INIT_POINTER(*fp, rtnl_dereference(f->next));
173 			tcf_unbind_filter(tp, &f->res);
174 			tcf_exts_get_net(&f->exts);
175 			tcf_queue_work(&f->rwork, fw_delete_filter_work);
176 			ret = 0;
177 			break;
178 		}
179 	}
180 
181 	*last = true;
182 	for (h = 0; h < HTSIZE; h++) {
183 		if (rcu_access_pointer(head->ht[h])) {
184 			*last = false;
185 			break;
186 		}
187 	}
188 
189 out:
190 	return ret;
191 }
192 
193 static const struct nla_policy fw_policy[TCA_FW_MAX + 1] = {
194 	[TCA_FW_CLASSID]	= { .type = NLA_U32 },
195 	[TCA_FW_INDEV]		= { .type = NLA_STRING, .len = IFNAMSIZ },
196 	[TCA_FW_MASK]		= { .type = NLA_U32 },
197 };
198 
199 static int fw_set_parms(struct net *net, struct tcf_proto *tp,
200 			struct fw_filter *f, struct nlattr **tb,
201 			struct nlattr **tca, unsigned long base, bool ovr,
202 			struct netlink_ext_ack *extack)
203 {
204 	struct fw_head *head = rtnl_dereference(tp->root);
205 	u32 mask;
206 	int err;
207 
208 	err = tcf_exts_validate(net, tp, tb, tca[TCA_RATE], &f->exts, ovr,
209 				true, extack);
210 	if (err < 0)
211 		return err;
212 
213 	if (tb[TCA_FW_CLASSID]) {
214 		f->res.classid = nla_get_u32(tb[TCA_FW_CLASSID]);
215 		tcf_bind_filter(tp, &f->res, base);
216 	}
217 
218 	if (tb[TCA_FW_INDEV]) {
219 		int ret;
220 		ret = tcf_change_indev(net, tb[TCA_FW_INDEV], extack);
221 		if (ret < 0)
222 			return ret;
223 		f->ifindex = ret;
224 	}
225 
226 	err = -EINVAL;
227 	if (tb[TCA_FW_MASK]) {
228 		mask = nla_get_u32(tb[TCA_FW_MASK]);
229 		if (mask != head->mask)
230 			return err;
231 	} else if (head->mask != 0xFFFFFFFF)
232 		return err;
233 
234 	return 0;
235 }
236 
237 static int fw_change(struct net *net, struct sk_buff *in_skb,
238 		     struct tcf_proto *tp, unsigned long base,
239 		     u32 handle, struct nlattr **tca, void **arg,
240 		     bool ovr, bool rtnl_held,
241 		     struct netlink_ext_ack *extack)
242 {
243 	struct fw_head *head = rtnl_dereference(tp->root);
244 	struct fw_filter *f = *arg;
245 	struct nlattr *opt = tca[TCA_OPTIONS];
246 	struct nlattr *tb[TCA_FW_MAX + 1];
247 	int err;
248 
249 	if (!opt)
250 		return handle ? -EINVAL : 0; /* Succeed if it is old method. */
251 
252 	err = nla_parse_nested_deprecated(tb, TCA_FW_MAX, opt, fw_policy,
253 					  NULL);
254 	if (err < 0)
255 		return err;
256 
257 	if (f) {
258 		struct fw_filter *pfp, *fnew;
259 		struct fw_filter __rcu **fp;
260 
261 		if (f->id != handle && handle)
262 			return -EINVAL;
263 
264 		fnew = kzalloc(sizeof(struct fw_filter), GFP_KERNEL);
265 		if (!fnew)
266 			return -ENOBUFS;
267 
268 		fnew->id = f->id;
269 		fnew->res = f->res;
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, ovr, 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, ovr, 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 (arg->count < arg->skip) {
363 				arg->count++;
364 				continue;
365 			}
366 			if (arg->fn(tp, f, arg) < 0) {
367 				arg->stop = 1;
368 				return;
369 			}
370 			arg->count++;
371 		}
372 	}
373 }
374 
375 static int fw_dump(struct net *net, struct tcf_proto *tp, void *fh,
376 		   struct sk_buff *skb, struct tcmsg *t, bool rtnl_held)
377 {
378 	struct fw_head *head = rtnl_dereference(tp->root);
379 	struct fw_filter *f = fh;
380 	struct nlattr *nest;
381 
382 	if (f == NULL)
383 		return skb->len;
384 
385 	t->tcm_handle = f->id;
386 
387 	if (!f->res.classid && !tcf_exts_has_actions(&f->exts))
388 		return skb->len;
389 
390 	nest = nla_nest_start_noflag(skb, TCA_OPTIONS);
391 	if (nest == NULL)
392 		goto nla_put_failure;
393 
394 	if (f->res.classid &&
395 	    nla_put_u32(skb, TCA_FW_CLASSID, f->res.classid))
396 		goto nla_put_failure;
397 	if (f->ifindex) {
398 		struct net_device *dev;
399 		dev = __dev_get_by_index(net, f->ifindex);
400 		if (dev && nla_put_string(skb, TCA_FW_INDEV, dev->name))
401 			goto nla_put_failure;
402 	}
403 	if (head->mask != 0xFFFFFFFF &&
404 	    nla_put_u32(skb, TCA_FW_MASK, head->mask))
405 		goto nla_put_failure;
406 
407 	if (tcf_exts_dump(skb, &f->exts) < 0)
408 		goto nla_put_failure;
409 
410 	nla_nest_end(skb, nest);
411 
412 	if (tcf_exts_dump_stats(skb, &f->exts) < 0)
413 		goto nla_put_failure;
414 
415 	return skb->len;
416 
417 nla_put_failure:
418 	nla_nest_cancel(skb, nest);
419 	return -1;
420 }
421 
422 static void fw_bind_class(void *fh, u32 classid, unsigned long cl, void *q,
423 			  unsigned long base)
424 {
425 	struct fw_filter *f = fh;
426 
427 	if (f && f->res.classid == classid) {
428 		if (cl)
429 			__tcf_bind_filter(q, &f->res, base);
430 		else
431 			__tcf_unbind_filter(q, &f->res);
432 	}
433 }
434 
435 static struct tcf_proto_ops cls_fw_ops __read_mostly = {
436 	.kind		=	"fw",
437 	.classify	=	fw_classify,
438 	.init		=	fw_init,
439 	.destroy	=	fw_destroy,
440 	.get		=	fw_get,
441 	.change		=	fw_change,
442 	.delete		=	fw_delete,
443 	.walk		=	fw_walk,
444 	.dump		=	fw_dump,
445 	.bind_class	=	fw_bind_class,
446 	.owner		=	THIS_MODULE,
447 };
448 
449 static int __init init_fw(void)
450 {
451 	return register_tcf_proto_ops(&cls_fw_ops);
452 }
453 
454 static void __exit exit_fw(void)
455 {
456 	unregister_tcf_proto_ops(&cls_fw_ops);
457 }
458 
459 module_init(init_fw)
460 module_exit(exit_fw)
461 MODULE_LICENSE("GPL");
462