xref: /openbmc/linux/net/sched/cls_api.c (revision 9ac8d3fb)
1 /*
2  * net/sched/cls_api.c	Packet classifier API.
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  *
13  * Eduardo J. Blanco <ejbs@netlabs.com.uy> :990222: kmod support
14  *
15  */
16 
17 #include <linux/module.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 <linux/init.h>
24 #include <linux/kmod.h>
25 #include <linux/netlink.h>
26 #include <linux/err.h>
27 #include <net/net_namespace.h>
28 #include <net/sock.h>
29 #include <net/netlink.h>
30 #include <net/pkt_sched.h>
31 #include <net/pkt_cls.h>
32 
33 /* The list of all installed classifier types */
34 
35 static struct tcf_proto_ops *tcf_proto_base __read_mostly;
36 
37 /* Protects list of registered TC modules. It is pure SMP lock. */
38 static DEFINE_RWLOCK(cls_mod_lock);
39 
40 /* Find classifier type by string name */
41 
42 static struct tcf_proto_ops *tcf_proto_lookup_ops(struct nlattr *kind)
43 {
44 	struct tcf_proto_ops *t = NULL;
45 
46 	if (kind) {
47 		read_lock(&cls_mod_lock);
48 		for (t = tcf_proto_base; t; t = t->next) {
49 			if (nla_strcmp(kind, t->kind) == 0) {
50 				if (!try_module_get(t->owner))
51 					t = NULL;
52 				break;
53 			}
54 		}
55 		read_unlock(&cls_mod_lock);
56 	}
57 	return t;
58 }
59 
60 /* Register(unregister) new classifier type */
61 
62 int register_tcf_proto_ops(struct tcf_proto_ops *ops)
63 {
64 	struct tcf_proto_ops *t, **tp;
65 	int rc = -EEXIST;
66 
67 	write_lock(&cls_mod_lock);
68 	for (tp = &tcf_proto_base; (t = *tp) != NULL; tp = &t->next)
69 		if (!strcmp(ops->kind, t->kind))
70 			goto out;
71 
72 	ops->next = NULL;
73 	*tp = ops;
74 	rc = 0;
75 out:
76 	write_unlock(&cls_mod_lock);
77 	return rc;
78 }
79 EXPORT_SYMBOL(register_tcf_proto_ops);
80 
81 int unregister_tcf_proto_ops(struct tcf_proto_ops *ops)
82 {
83 	struct tcf_proto_ops *t, **tp;
84 	int rc = -ENOENT;
85 
86 	write_lock(&cls_mod_lock);
87 	for (tp = &tcf_proto_base; (t=*tp) != NULL; tp = &t->next)
88 		if (t == ops)
89 			break;
90 
91 	if (!t)
92 		goto out;
93 	*tp = t->next;
94 	rc = 0;
95 out:
96 	write_unlock(&cls_mod_lock);
97 	return rc;
98 }
99 EXPORT_SYMBOL(unregister_tcf_proto_ops);
100 
101 static int tfilter_notify(struct sk_buff *oskb, struct nlmsghdr *n,
102 			  struct tcf_proto *tp, unsigned long fh, int event);
103 
104 
105 /* Select new prio value from the range, managed by kernel. */
106 
107 static inline u32 tcf_auto_prio(struct tcf_proto *tp)
108 {
109 	u32 first = TC_H_MAKE(0xC0000000U, 0U);
110 
111 	if (tp)
112 		first = tp->prio-1;
113 
114 	return first;
115 }
116 
117 /* Add/change/delete/get a filter node */
118 
119 static int tc_ctl_tfilter(struct sk_buff *skb, struct nlmsghdr *n, void *arg)
120 {
121 	struct net *net = sock_net(skb->sk);
122 	struct nlattr *tca[TCA_MAX + 1];
123 	spinlock_t *root_lock;
124 	struct tcmsg *t;
125 	u32 protocol;
126 	u32 prio;
127 	u32 nprio;
128 	u32 parent;
129 	struct net_device *dev;
130 	struct Qdisc  *q;
131 	struct tcf_proto **back, **chain;
132 	struct tcf_proto *tp;
133 	struct tcf_proto_ops *tp_ops;
134 	const struct Qdisc_class_ops *cops;
135 	unsigned long cl;
136 	unsigned long fh;
137 	int err;
138 
139 	if (net != &init_net)
140 		return -EINVAL;
141 
142 replay:
143 	t = NLMSG_DATA(n);
144 	protocol = TC_H_MIN(t->tcm_info);
145 	prio = TC_H_MAJ(t->tcm_info);
146 	nprio = prio;
147 	parent = t->tcm_parent;
148 	cl = 0;
149 
150 	if (prio == 0) {
151 		/* If no priority is given, user wants we allocated it. */
152 		if (n->nlmsg_type != RTM_NEWTFILTER || !(n->nlmsg_flags&NLM_F_CREATE))
153 			return -ENOENT;
154 		prio = TC_H_MAKE(0x80000000U, 0U);
155 	}
156 
157 	/* Find head of filter chain. */
158 
159 	/* Find link */
160 	dev = __dev_get_by_index(&init_net, t->tcm_ifindex);
161 	if (dev == NULL)
162 		return -ENODEV;
163 
164 	err = nlmsg_parse(n, sizeof(*t), tca, TCA_MAX, NULL);
165 	if (err < 0)
166 		return err;
167 
168 	/* Find qdisc */
169 	if (!parent) {
170 		struct netdev_queue *dev_queue = netdev_get_tx_queue(dev, 0);
171 		q = dev_queue->qdisc_sleeping;
172 		parent = q->handle;
173 	} else {
174 		q = qdisc_lookup(dev, TC_H_MAJ(t->tcm_parent));
175 		if (q == NULL)
176 			return -EINVAL;
177 	}
178 
179 	/* Is it classful? */
180 	if ((cops = q->ops->cl_ops) == NULL)
181 		return -EINVAL;
182 
183 	/* Do we search for filter, attached to class? */
184 	if (TC_H_MIN(parent)) {
185 		cl = cops->get(q, parent);
186 		if (cl == 0)
187 			return -ENOENT;
188 	}
189 
190 	/* And the last stroke */
191 	chain = cops->tcf_chain(q, cl);
192 	err = -EINVAL;
193 	if (chain == NULL)
194 		goto errout;
195 
196 	/* Check the chain for existence of proto-tcf with this priority */
197 	for (back = chain; (tp=*back) != NULL; back = &tp->next) {
198 		if (tp->prio >= prio) {
199 			if (tp->prio == prio) {
200 				if (!nprio || (tp->protocol != protocol && protocol))
201 					goto errout;
202 			} else
203 				tp = NULL;
204 			break;
205 		}
206 	}
207 
208 	root_lock = qdisc_root_sleeping_lock(q);
209 
210 	if (tp == NULL) {
211 		/* Proto-tcf does not exist, create new one */
212 
213 		if (tca[TCA_KIND] == NULL || !protocol)
214 			goto errout;
215 
216 		err = -ENOENT;
217 		if (n->nlmsg_type != RTM_NEWTFILTER || !(n->nlmsg_flags&NLM_F_CREATE))
218 			goto errout;
219 
220 
221 		/* Create new proto tcf */
222 
223 		err = -ENOBUFS;
224 		tp = kzalloc(sizeof(*tp), GFP_KERNEL);
225 		if (tp == NULL)
226 			goto errout;
227 		err = -ENOENT;
228 		tp_ops = tcf_proto_lookup_ops(tca[TCA_KIND]);
229 		if (tp_ops == NULL) {
230 #ifdef CONFIG_MODULES
231 			struct nlattr *kind = tca[TCA_KIND];
232 			char name[IFNAMSIZ];
233 
234 			if (kind != NULL &&
235 			    nla_strlcpy(name, kind, IFNAMSIZ) < IFNAMSIZ) {
236 				rtnl_unlock();
237 				request_module("cls_%s", name);
238 				rtnl_lock();
239 				tp_ops = tcf_proto_lookup_ops(kind);
240 				/* We dropped the RTNL semaphore in order to
241 				 * perform the module load.  So, even if we
242 				 * succeeded in loading the module we have to
243 				 * replay the request.  We indicate this using
244 				 * -EAGAIN.
245 				 */
246 				if (tp_ops != NULL) {
247 					module_put(tp_ops->owner);
248 					err = -EAGAIN;
249 				}
250 			}
251 #endif
252 			kfree(tp);
253 			goto errout;
254 		}
255 		tp->ops = tp_ops;
256 		tp->protocol = protocol;
257 		tp->prio = nprio ? : tcf_auto_prio(*back);
258 		tp->q = q;
259 		tp->classify = tp_ops->classify;
260 		tp->classid = parent;
261 
262 		err = tp_ops->init(tp);
263 		if (err != 0) {
264 			module_put(tp_ops->owner);
265 			kfree(tp);
266 			goto errout;
267 		}
268 
269 		spin_lock_bh(root_lock);
270 		tp->next = *back;
271 		*back = tp;
272 		spin_unlock_bh(root_lock);
273 
274 	} else if (tca[TCA_KIND] && nla_strcmp(tca[TCA_KIND], tp->ops->kind))
275 		goto errout;
276 
277 	fh = tp->ops->get(tp, t->tcm_handle);
278 
279 	if (fh == 0) {
280 		if (n->nlmsg_type == RTM_DELTFILTER && t->tcm_handle == 0) {
281 			spin_lock_bh(root_lock);
282 			*back = tp->next;
283 			spin_unlock_bh(root_lock);
284 
285 			tfilter_notify(skb, n, tp, fh, RTM_DELTFILTER);
286 			tcf_destroy(tp);
287 			err = 0;
288 			goto errout;
289 		}
290 
291 		err = -ENOENT;
292 		if (n->nlmsg_type != RTM_NEWTFILTER ||
293 		    !(n->nlmsg_flags & NLM_F_CREATE))
294 			goto errout;
295 	} else {
296 		switch (n->nlmsg_type) {
297 		case RTM_NEWTFILTER:
298 			err = -EEXIST;
299 			if (n->nlmsg_flags & NLM_F_EXCL)
300 				goto errout;
301 			break;
302 		case RTM_DELTFILTER:
303 			err = tp->ops->delete(tp, fh);
304 			if (err == 0)
305 				tfilter_notify(skb, n, tp, fh, RTM_DELTFILTER);
306 			goto errout;
307 		case RTM_GETTFILTER:
308 			err = tfilter_notify(skb, n, tp, fh, RTM_NEWTFILTER);
309 			goto errout;
310 		default:
311 			err = -EINVAL;
312 			goto errout;
313 		}
314 	}
315 
316 	err = tp->ops->change(tp, cl, t->tcm_handle, tca, &fh);
317 	if (err == 0)
318 		tfilter_notify(skb, n, tp, fh, RTM_NEWTFILTER);
319 
320 errout:
321 	if (cl)
322 		cops->put(q, cl);
323 	if (err == -EAGAIN)
324 		/* Replay the request. */
325 		goto replay;
326 	return err;
327 }
328 
329 static int tcf_fill_node(struct sk_buff *skb, struct tcf_proto *tp,
330 			 unsigned long fh, u32 pid, u32 seq, u16 flags, int event)
331 {
332 	struct tcmsg *tcm;
333 	struct nlmsghdr  *nlh;
334 	unsigned char *b = skb_tail_pointer(skb);
335 
336 	nlh = NLMSG_NEW(skb, pid, seq, event, sizeof(*tcm), flags);
337 	tcm = NLMSG_DATA(nlh);
338 	tcm->tcm_family = AF_UNSPEC;
339 	tcm->tcm__pad1 = 0;
340 	tcm->tcm__pad1 = 0;
341 	tcm->tcm_ifindex = qdisc_dev(tp->q)->ifindex;
342 	tcm->tcm_parent = tp->classid;
343 	tcm->tcm_info = TC_H_MAKE(tp->prio, tp->protocol);
344 	NLA_PUT_STRING(skb, TCA_KIND, tp->ops->kind);
345 	tcm->tcm_handle = fh;
346 	if (RTM_DELTFILTER != event) {
347 		tcm->tcm_handle = 0;
348 		if (tp->ops->dump && tp->ops->dump(tp, fh, skb, tcm) < 0)
349 			goto nla_put_failure;
350 	}
351 	nlh->nlmsg_len = skb_tail_pointer(skb) - b;
352 	return skb->len;
353 
354 nlmsg_failure:
355 nla_put_failure:
356 	nlmsg_trim(skb, b);
357 	return -1;
358 }
359 
360 static int tfilter_notify(struct sk_buff *oskb, struct nlmsghdr *n,
361 			  struct tcf_proto *tp, unsigned long fh, int event)
362 {
363 	struct sk_buff *skb;
364 	u32 pid = oskb ? NETLINK_CB(oskb).pid : 0;
365 
366 	skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
367 	if (!skb)
368 		return -ENOBUFS;
369 
370 	if (tcf_fill_node(skb, tp, fh, pid, n->nlmsg_seq, 0, event) <= 0) {
371 		kfree_skb(skb);
372 		return -EINVAL;
373 	}
374 
375 	return rtnetlink_send(skb, &init_net, pid, RTNLGRP_TC,
376 			      n->nlmsg_flags & NLM_F_ECHO);
377 }
378 
379 struct tcf_dump_args {
380 	struct tcf_walker w;
381 	struct sk_buff *skb;
382 	struct netlink_callback *cb;
383 };
384 
385 static int tcf_node_dump(struct tcf_proto *tp, unsigned long n,
386 			 struct tcf_walker *arg)
387 {
388 	struct tcf_dump_args *a = (void *)arg;
389 
390 	return tcf_fill_node(a->skb, tp, n, NETLINK_CB(a->cb->skb).pid,
391 			     a->cb->nlh->nlmsg_seq, NLM_F_MULTI, RTM_NEWTFILTER);
392 }
393 
394 static int tc_dump_tfilter(struct sk_buff *skb, struct netlink_callback *cb)
395 {
396 	struct net *net = sock_net(skb->sk);
397 	struct netdev_queue *dev_queue;
398 	int t;
399 	int s_t;
400 	struct net_device *dev;
401 	struct Qdisc *q;
402 	struct tcf_proto *tp, **chain;
403 	struct tcmsg *tcm = (struct tcmsg *)NLMSG_DATA(cb->nlh);
404 	unsigned long cl = 0;
405 	const struct Qdisc_class_ops *cops;
406 	struct tcf_dump_args arg;
407 
408 	if (net != &init_net)
409 		return 0;
410 
411 	if (cb->nlh->nlmsg_len < NLMSG_LENGTH(sizeof(*tcm)))
412 		return skb->len;
413 	if ((dev = dev_get_by_index(&init_net, tcm->tcm_ifindex)) == NULL)
414 		return skb->len;
415 
416 	dev_queue = netdev_get_tx_queue(dev, 0);
417 	if (!tcm->tcm_parent)
418 		q = dev_queue->qdisc_sleeping;
419 	else
420 		q = qdisc_lookup(dev, TC_H_MAJ(tcm->tcm_parent));
421 	if (!q)
422 		goto out;
423 	if ((cops = q->ops->cl_ops) == NULL)
424 		goto errout;
425 	if (TC_H_MIN(tcm->tcm_parent)) {
426 		cl = cops->get(q, tcm->tcm_parent);
427 		if (cl == 0)
428 			goto errout;
429 	}
430 	chain = cops->tcf_chain(q, cl);
431 	if (chain == NULL)
432 		goto errout;
433 
434 	s_t = cb->args[0];
435 
436 	for (tp=*chain, t=0; tp; tp = tp->next, t++) {
437 		if (t < s_t) continue;
438 		if (TC_H_MAJ(tcm->tcm_info) &&
439 		    TC_H_MAJ(tcm->tcm_info) != tp->prio)
440 			continue;
441 		if (TC_H_MIN(tcm->tcm_info) &&
442 		    TC_H_MIN(tcm->tcm_info) != tp->protocol)
443 			continue;
444 		if (t > s_t)
445 			memset(&cb->args[1], 0, sizeof(cb->args)-sizeof(cb->args[0]));
446 		if (cb->args[1] == 0) {
447 			if (tcf_fill_node(skb, tp, 0, NETLINK_CB(cb->skb).pid,
448 					  cb->nlh->nlmsg_seq, NLM_F_MULTI,
449 					  RTM_NEWTFILTER) <= 0)
450 				break;
451 
452 			cb->args[1] = 1;
453 		}
454 		if (tp->ops->walk == NULL)
455 			continue;
456 		arg.w.fn = tcf_node_dump;
457 		arg.skb = skb;
458 		arg.cb = cb;
459 		arg.w.stop = 0;
460 		arg.w.skip = cb->args[1]-1;
461 		arg.w.count = 0;
462 		tp->ops->walk(tp, &arg.w);
463 		cb->args[1] = arg.w.count+1;
464 		if (arg.w.stop)
465 			break;
466 	}
467 
468 	cb->args[0] = t;
469 
470 errout:
471 	if (cl)
472 		cops->put(q, cl);
473 out:
474 	dev_put(dev);
475 	return skb->len;
476 }
477 
478 void tcf_exts_destroy(struct tcf_proto *tp, struct tcf_exts *exts)
479 {
480 #ifdef CONFIG_NET_CLS_ACT
481 	if (exts->action) {
482 		tcf_action_destroy(exts->action, TCA_ACT_UNBIND);
483 		exts->action = NULL;
484 	}
485 #endif
486 }
487 EXPORT_SYMBOL(tcf_exts_destroy);
488 
489 int tcf_exts_validate(struct tcf_proto *tp, struct nlattr **tb,
490 		  struct nlattr *rate_tlv, struct tcf_exts *exts,
491 		  const struct tcf_ext_map *map)
492 {
493 	memset(exts, 0, sizeof(*exts));
494 
495 #ifdef CONFIG_NET_CLS_ACT
496 	{
497 		struct tc_action *act;
498 
499 		if (map->police && tb[map->police]) {
500 			act = tcf_action_init_1(tb[map->police], rate_tlv,
501 						"police", TCA_ACT_NOREPLACE,
502 						TCA_ACT_BIND);
503 			if (IS_ERR(act))
504 				return PTR_ERR(act);
505 
506 			act->type = TCA_OLD_COMPAT;
507 			exts->action = act;
508 		} else if (map->action && tb[map->action]) {
509 			act = tcf_action_init(tb[map->action], rate_tlv, NULL,
510 					      TCA_ACT_NOREPLACE, TCA_ACT_BIND);
511 			if (IS_ERR(act))
512 				return PTR_ERR(act);
513 
514 			exts->action = act;
515 		}
516 	}
517 #else
518 	if ((map->action && tb[map->action]) ||
519 	    (map->police && tb[map->police]))
520 		return -EOPNOTSUPP;
521 #endif
522 
523 	return 0;
524 }
525 EXPORT_SYMBOL(tcf_exts_validate);
526 
527 void tcf_exts_change(struct tcf_proto *tp, struct tcf_exts *dst,
528 		     struct tcf_exts *src)
529 {
530 #ifdef CONFIG_NET_CLS_ACT
531 	if (src->action) {
532 		struct tc_action *act;
533 		tcf_tree_lock(tp);
534 		act = xchg(&dst->action, src->action);
535 		tcf_tree_unlock(tp);
536 		if (act)
537 			tcf_action_destroy(act, TCA_ACT_UNBIND);
538 	}
539 #endif
540 }
541 EXPORT_SYMBOL(tcf_exts_change);
542 
543 int tcf_exts_dump(struct sk_buff *skb, struct tcf_exts *exts,
544 		  const struct tcf_ext_map *map)
545 {
546 #ifdef CONFIG_NET_CLS_ACT
547 	if (map->action && exts->action) {
548 		/*
549 		 * again for backward compatible mode - we want
550 		 * to work with both old and new modes of entering
551 		 * tc data even if iproute2  was newer - jhs
552 		 */
553 		struct nlattr *nest;
554 
555 		if (exts->action->type != TCA_OLD_COMPAT) {
556 			nest = nla_nest_start(skb, map->action);
557 			if (nest == NULL)
558 				goto nla_put_failure;
559 			if (tcf_action_dump(skb, exts->action, 0, 0) < 0)
560 				goto nla_put_failure;
561 			nla_nest_end(skb, nest);
562 		} else if (map->police) {
563 			nest = nla_nest_start(skb, map->police);
564 			if (nest == NULL)
565 				goto nla_put_failure;
566 			if (tcf_action_dump_old(skb, exts->action, 0, 0) < 0)
567 				goto nla_put_failure;
568 			nla_nest_end(skb, nest);
569 		}
570 	}
571 #endif
572 	return 0;
573 nla_put_failure: __attribute__ ((unused))
574 	return -1;
575 }
576 EXPORT_SYMBOL(tcf_exts_dump);
577 
578 
579 int tcf_exts_dump_stats(struct sk_buff *skb, struct tcf_exts *exts,
580 			const struct tcf_ext_map *map)
581 {
582 #ifdef CONFIG_NET_CLS_ACT
583 	if (exts->action)
584 		if (tcf_action_copy_stats(skb, exts->action, 1) < 0)
585 			goto nla_put_failure;
586 #endif
587 	return 0;
588 nla_put_failure: __attribute__ ((unused))
589 	return -1;
590 }
591 EXPORT_SYMBOL(tcf_exts_dump_stats);
592 
593 static int __init tc_filter_init(void)
594 {
595 	rtnl_register(PF_UNSPEC, RTM_NEWTFILTER, tc_ctl_tfilter, NULL);
596 	rtnl_register(PF_UNSPEC, RTM_DELTFILTER, tc_ctl_tfilter, NULL);
597 	rtnl_register(PF_UNSPEC, RTM_GETTFILTER, tc_ctl_tfilter,
598 						 tc_dump_tfilter);
599 
600 	return 0;
601 }
602 
603 subsys_initcall(tc_filter_init);
604