xref: /openbmc/linux/net/sched/cls_api.c (revision d5cb9783536a41df9f9cba5b0a1d78047ed787f7)
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 <asm/uaccess.h>
18 #include <asm/system.h>
19 #include <linux/bitops.h>
20 #include <linux/config.h>
21 #include <linux/module.h>
22 #include <linux/types.h>
23 #include <linux/kernel.h>
24 #include <linux/sched.h>
25 #include <linux/string.h>
26 #include <linux/mm.h>
27 #include <linux/socket.h>
28 #include <linux/sockios.h>
29 #include <linux/in.h>
30 #include <linux/errno.h>
31 #include <linux/interrupt.h>
32 #include <linux/netdevice.h>
33 #include <linux/skbuff.h>
34 #include <linux/rtnetlink.h>
35 #include <linux/init.h>
36 #include <linux/kmod.h>
37 #include <net/sock.h>
38 #include <net/pkt_sched.h>
39 #include <net/pkt_cls.h>
40 
41 #if 0 /* control */
42 #define DPRINTK(format,args...) printk(KERN_DEBUG format,##args)
43 #else
44 #define DPRINTK(format,args...)
45 #endif
46 
47 /* The list of all installed classifier types */
48 
49 static struct tcf_proto_ops *tcf_proto_base;
50 
51 /* Protects list of registered TC modules. It is pure SMP lock. */
52 static DEFINE_RWLOCK(cls_mod_lock);
53 
54 /* Find classifier type by string name */
55 
56 static struct tcf_proto_ops * tcf_proto_lookup_ops(struct rtattr *kind)
57 {
58 	struct tcf_proto_ops *t = NULL;
59 
60 	if (kind) {
61 		read_lock(&cls_mod_lock);
62 		for (t = tcf_proto_base; t; t = t->next) {
63 			if (rtattr_strcmp(kind, t->kind) == 0) {
64 				if (!try_module_get(t->owner))
65 					t = NULL;
66 				break;
67 			}
68 		}
69 		read_unlock(&cls_mod_lock);
70 	}
71 	return t;
72 }
73 
74 /* Register(unregister) new classifier type */
75 
76 int register_tcf_proto_ops(struct tcf_proto_ops *ops)
77 {
78 	struct tcf_proto_ops *t, **tp;
79 	int rc = -EEXIST;
80 
81 	write_lock(&cls_mod_lock);
82 	for (tp = &tcf_proto_base; (t = *tp) != NULL; tp = &t->next)
83 		if (!strcmp(ops->kind, t->kind))
84 			goto out;
85 
86 	ops->next = NULL;
87 	*tp = ops;
88 	rc = 0;
89 out:
90 	write_unlock(&cls_mod_lock);
91 	return rc;
92 }
93 
94 int unregister_tcf_proto_ops(struct tcf_proto_ops *ops)
95 {
96 	struct tcf_proto_ops *t, **tp;
97 	int rc = -ENOENT;
98 
99 	write_lock(&cls_mod_lock);
100 	for (tp = &tcf_proto_base; (t=*tp) != NULL; tp = &t->next)
101 		if (t == ops)
102 			break;
103 
104 	if (!t)
105 		goto out;
106 	*tp = t->next;
107 	rc = 0;
108 out:
109 	write_unlock(&cls_mod_lock);
110 	return rc;
111 }
112 
113 static int tfilter_notify(struct sk_buff *oskb, struct nlmsghdr *n,
114 			  struct tcf_proto *tp, unsigned long fh, int event);
115 
116 
117 /* Select new prio value from the range, managed by kernel. */
118 
119 static __inline__ u32 tcf_auto_prio(struct tcf_proto *tp)
120 {
121 	u32 first = TC_H_MAKE(0xC0000000U,0U);
122 
123 	if (tp)
124 		first = tp->prio-1;
125 
126 	return first;
127 }
128 
129 /* Add/change/delete/get a filter node */
130 
131 static int tc_ctl_tfilter(struct sk_buff *skb, struct nlmsghdr *n, void *arg)
132 {
133 	struct rtattr **tca;
134 	struct tcmsg *t;
135 	u32 protocol;
136 	u32 prio;
137 	u32 nprio;
138 	u32 parent;
139 	struct net_device *dev;
140 	struct Qdisc  *q;
141 	struct tcf_proto **back, **chain;
142 	struct tcf_proto *tp;
143 	struct tcf_proto_ops *tp_ops;
144 	struct Qdisc_class_ops *cops;
145 	unsigned long cl;
146 	unsigned long fh;
147 	int err;
148 
149 replay:
150 	tca = arg;
151 	t = NLMSG_DATA(n);
152 	protocol = TC_H_MIN(t->tcm_info);
153 	prio = TC_H_MAJ(t->tcm_info);
154 	nprio = prio;
155 	parent = t->tcm_parent;
156 	cl = 0;
157 
158 	if (prio == 0) {
159 		/* If no priority is given, user wants we allocated it. */
160 		if (n->nlmsg_type != RTM_NEWTFILTER || !(n->nlmsg_flags&NLM_F_CREATE))
161 			return -ENOENT;
162 		prio = TC_H_MAKE(0x80000000U,0U);
163 	}
164 
165 	/* Find head of filter chain. */
166 
167 	/* Find link */
168 	if ((dev = __dev_get_by_index(t->tcm_ifindex)) == NULL)
169 		return -ENODEV;
170 
171 	/* Find qdisc */
172 	if (!parent) {
173 		q = dev->qdisc_sleeping;
174 		parent = q->handle;
175 	} else if ((q = qdisc_lookup(dev, TC_H_MAJ(t->tcm_parent))) == NULL)
176 		return -EINVAL;
177 
178 	/* Is it classful? */
179 	if ((cops = q->ops->cl_ops) == NULL)
180 		return -EINVAL;
181 
182 	/* Do we search for filter, attached to class? */
183 	if (TC_H_MIN(parent)) {
184 		cl = cops->get(q, parent);
185 		if (cl == 0)
186 			return -ENOENT;
187 	}
188 
189 	/* And the last stroke */
190 	chain = cops->tcf_chain(q, cl);
191 	err = -EINVAL;
192 	if (chain == NULL)
193 		goto errout;
194 
195 	/* Check the chain for existence of proto-tcf with this priority */
196 	for (back = chain; (tp=*back) != NULL; back = &tp->next) {
197 		if (tp->prio >= prio) {
198 			if (tp->prio == prio) {
199 				if (!nprio || (tp->protocol != protocol && protocol))
200 					goto errout;
201 			} else
202 				tp = NULL;
203 			break;
204 		}
205 	}
206 
207 	if (tp == NULL) {
208 		/* Proto-tcf does not exist, create new one */
209 
210 		if (tca[TCA_KIND-1] == NULL || !protocol)
211 			goto errout;
212 
213 		err = -ENOENT;
214 		if (n->nlmsg_type != RTM_NEWTFILTER || !(n->nlmsg_flags&NLM_F_CREATE))
215 			goto errout;
216 
217 
218 		/* Create new proto tcf */
219 
220 		err = -ENOBUFS;
221 		if ((tp = kmalloc(sizeof(*tp), GFP_KERNEL)) == NULL)
222 			goto errout;
223 		err = -EINVAL;
224 		tp_ops = tcf_proto_lookup_ops(tca[TCA_KIND-1]);
225 		if (tp_ops == NULL) {
226 #ifdef CONFIG_KMOD
227 			struct rtattr *kind = tca[TCA_KIND-1];
228 			char name[IFNAMSIZ];
229 
230 			if (kind != NULL &&
231 			    rtattr_strlcpy(name, kind, IFNAMSIZ) < IFNAMSIZ) {
232 				rtnl_unlock();
233 				request_module("cls_%s", name);
234 				rtnl_lock();
235 				tp_ops = tcf_proto_lookup_ops(kind);
236 				/* We dropped the RTNL semaphore in order to
237 				 * perform the module load.  So, even if we
238 				 * succeeded in loading the module we have to
239 				 * replay the request.  We indicate this using
240 				 * -EAGAIN.
241 				 */
242 				if (tp_ops != NULL) {
243 					module_put(tp_ops->owner);
244 					err = -EAGAIN;
245 				}
246 			}
247 #endif
248 			kfree(tp);
249 			goto errout;
250 		}
251 		memset(tp, 0, sizeof(*tp));
252 		tp->ops = tp_ops;
253 		tp->protocol = protocol;
254 		tp->prio = nprio ? : tcf_auto_prio(*back);
255 		tp->q = q;
256 		tp->classify = tp_ops->classify;
257 		tp->classid = parent;
258 		if ((err = tp_ops->init(tp)) != 0) {
259 			module_put(tp_ops->owner);
260 			kfree(tp);
261 			goto errout;
262 		}
263 
264 		qdisc_lock_tree(dev);
265 		tp->next = *back;
266 		*back = tp;
267 		qdisc_unlock_tree(dev);
268 
269 	} else if (tca[TCA_KIND-1] && rtattr_strcmp(tca[TCA_KIND-1], tp->ops->kind))
270 		goto errout;
271 
272 	fh = tp->ops->get(tp, t->tcm_handle);
273 
274 	if (fh == 0) {
275 		if (n->nlmsg_type == RTM_DELTFILTER && t->tcm_handle == 0) {
276 			qdisc_lock_tree(dev);
277 			*back = tp->next;
278 			qdisc_unlock_tree(dev);
279 
280 			tfilter_notify(skb, n, tp, fh, RTM_DELTFILTER);
281 			tcf_destroy(tp);
282 			err = 0;
283 			goto errout;
284 		}
285 
286 		err = -ENOENT;
287 		if (n->nlmsg_type != RTM_NEWTFILTER || !(n->nlmsg_flags&NLM_F_CREATE))
288 			goto errout;
289 	} else {
290 		switch (n->nlmsg_type) {
291 		case RTM_NEWTFILTER:
292 			err = -EEXIST;
293 			if (n->nlmsg_flags&NLM_F_EXCL)
294 				goto errout;
295 			break;
296 		case RTM_DELTFILTER:
297 			err = tp->ops->delete(tp, fh);
298 			if (err == 0)
299 				tfilter_notify(skb, n, tp, fh, RTM_DELTFILTER);
300 			goto errout;
301 		case RTM_GETTFILTER:
302 			err = tfilter_notify(skb, n, tp, fh, RTM_NEWTFILTER);
303 			goto errout;
304 		default:
305 			err = -EINVAL;
306 			goto errout;
307 		}
308 	}
309 
310 	err = tp->ops->change(tp, cl, t->tcm_handle, tca, &fh);
311 	if (err == 0)
312 		tfilter_notify(skb, n, tp, fh, RTM_NEWTFILTER);
313 
314 errout:
315 	if (cl)
316 		cops->put(q, cl);
317 	if (err == -EAGAIN)
318 		/* Replay the request. */
319 		goto replay;
320 	return err;
321 }
322 
323 static int
324 tcf_fill_node(struct sk_buff *skb, struct tcf_proto *tp, unsigned long fh,
325 	      u32 pid, u32 seq, u16 flags, int event)
326 {
327 	struct tcmsg *tcm;
328 	struct nlmsghdr  *nlh;
329 	unsigned char	 *b = skb->tail;
330 
331 	nlh = NLMSG_NEW(skb, pid, seq, event, sizeof(*tcm), flags);
332 	tcm = NLMSG_DATA(nlh);
333 	tcm->tcm_family = AF_UNSPEC;
334 	tcm->tcm__pad1 = 0;
335 	tcm->tcm__pad1 = 0;
336 	tcm->tcm_ifindex = tp->q->dev->ifindex;
337 	tcm->tcm_parent = tp->classid;
338 	tcm->tcm_info = TC_H_MAKE(tp->prio, tp->protocol);
339 	RTA_PUT(skb, TCA_KIND, IFNAMSIZ, tp->ops->kind);
340 	tcm->tcm_handle = fh;
341 	if (RTM_DELTFILTER != event) {
342 		tcm->tcm_handle = 0;
343 		if (tp->ops->dump && tp->ops->dump(tp, fh, skb, tcm) < 0)
344 			goto rtattr_failure;
345 	}
346 	nlh->nlmsg_len = skb->tail - b;
347 	return skb->len;
348 
349 nlmsg_failure:
350 rtattr_failure:
351 	skb_trim(skb, b - skb->data);
352 	return -1;
353 }
354 
355 static int tfilter_notify(struct sk_buff *oskb, struct nlmsghdr *n,
356 			  struct tcf_proto *tp, unsigned long fh, int event)
357 {
358 	struct sk_buff *skb;
359 	u32 pid = oskb ? NETLINK_CB(oskb).pid : 0;
360 
361 	skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
362 	if (!skb)
363 		return -ENOBUFS;
364 
365 	if (tcf_fill_node(skb, tp, fh, pid, n->nlmsg_seq, 0, event) <= 0) {
366 		kfree_skb(skb);
367 		return -EINVAL;
368 	}
369 
370 	return rtnetlink_send(skb, pid, RTNLGRP_TC, n->nlmsg_flags&NLM_F_ECHO);
371 }
372 
373 struct tcf_dump_args
374 {
375 	struct tcf_walker w;
376 	struct sk_buff *skb;
377 	struct netlink_callback *cb;
378 };
379 
380 static int tcf_node_dump(struct tcf_proto *tp, unsigned long n, struct tcf_walker *arg)
381 {
382 	struct tcf_dump_args *a = (void*)arg;
383 
384 	return tcf_fill_node(a->skb, tp, n, NETLINK_CB(a->cb->skb).pid,
385 			     a->cb->nlh->nlmsg_seq, NLM_F_MULTI, RTM_NEWTFILTER);
386 }
387 
388 static int tc_dump_tfilter(struct sk_buff *skb, struct netlink_callback *cb)
389 {
390 	int t;
391 	int s_t;
392 	struct net_device *dev;
393 	struct Qdisc *q;
394 	struct tcf_proto *tp, **chain;
395 	struct tcmsg *tcm = (struct tcmsg*)NLMSG_DATA(cb->nlh);
396 	unsigned long cl = 0;
397 	struct Qdisc_class_ops *cops;
398 	struct tcf_dump_args arg;
399 
400 	if (cb->nlh->nlmsg_len < NLMSG_LENGTH(sizeof(*tcm)))
401 		return skb->len;
402 	if ((dev = dev_get_by_index(tcm->tcm_ifindex)) == NULL)
403 		return skb->len;
404 
405 	read_lock_bh(&qdisc_tree_lock);
406 	if (!tcm->tcm_parent)
407 		q = dev->qdisc_sleeping;
408 	else
409 		q = qdisc_lookup(dev, TC_H_MAJ(tcm->tcm_parent));
410 	if (!q)
411 		goto out;
412 	if ((cops = q->ops->cl_ops) == NULL)
413 		goto errout;
414 	if (TC_H_MIN(tcm->tcm_parent)) {
415 		cl = cops->get(q, tcm->tcm_parent);
416 		if (cl == 0)
417 			goto errout;
418 	}
419 	chain = cops->tcf_chain(q, cl);
420 	if (chain == NULL)
421 		goto errout;
422 
423 	s_t = cb->args[0];
424 
425 	for (tp=*chain, t=0; tp; tp = tp->next, t++) {
426 		if (t < s_t) continue;
427 		if (TC_H_MAJ(tcm->tcm_info) &&
428 		    TC_H_MAJ(tcm->tcm_info) != tp->prio)
429 			continue;
430 		if (TC_H_MIN(tcm->tcm_info) &&
431 		    TC_H_MIN(tcm->tcm_info) != tp->protocol)
432 			continue;
433 		if (t > s_t)
434 			memset(&cb->args[1], 0, sizeof(cb->args)-sizeof(cb->args[0]));
435 		if (cb->args[1] == 0) {
436 			if (tcf_fill_node(skb, tp, 0, NETLINK_CB(cb->skb).pid,
437 					  cb->nlh->nlmsg_seq, NLM_F_MULTI, RTM_NEWTFILTER) <= 0) {
438 				break;
439 			}
440 			cb->args[1] = 1;
441 		}
442 		if (tp->ops->walk == NULL)
443 			continue;
444 		arg.w.fn = tcf_node_dump;
445 		arg.skb = skb;
446 		arg.cb = cb;
447 		arg.w.stop = 0;
448 		arg.w.skip = cb->args[1]-1;
449 		arg.w.count = 0;
450 		tp->ops->walk(tp, &arg.w);
451 		cb->args[1] = arg.w.count+1;
452 		if (arg.w.stop)
453 			break;
454 	}
455 
456 	cb->args[0] = t;
457 
458 errout:
459 	if (cl)
460 		cops->put(q, cl);
461 out:
462 	read_unlock_bh(&qdisc_tree_lock);
463 	dev_put(dev);
464 	return skb->len;
465 }
466 
467 void
468 tcf_exts_destroy(struct tcf_proto *tp, struct tcf_exts *exts)
469 {
470 #ifdef CONFIG_NET_CLS_ACT
471 	if (exts->action) {
472 		tcf_action_destroy(exts->action, TCA_ACT_UNBIND);
473 		exts->action = NULL;
474 	}
475 #elif defined CONFIG_NET_CLS_POLICE
476 	if (exts->police) {
477 		tcf_police_release(exts->police, TCA_ACT_UNBIND);
478 		exts->police = NULL;
479 	}
480 #endif
481 }
482 
483 
484 int
485 tcf_exts_validate(struct tcf_proto *tp, struct rtattr **tb,
486 	          struct rtattr *rate_tlv, struct tcf_exts *exts,
487 	          struct tcf_ext_map *map)
488 {
489 	memset(exts, 0, sizeof(*exts));
490 
491 #ifdef CONFIG_NET_CLS_ACT
492 	{
493 		int err;
494 		struct tc_action *act;
495 
496 		if (map->police && tb[map->police-1]) {
497 			act = tcf_action_init_1(tb[map->police-1], rate_tlv, "police",
498 				TCA_ACT_NOREPLACE, TCA_ACT_BIND, &err);
499 			if (act == NULL)
500 				return err;
501 
502 			act->type = TCA_OLD_COMPAT;
503 			exts->action = act;
504 		} else if (map->action && tb[map->action-1]) {
505 			act = tcf_action_init(tb[map->action-1], rate_tlv, NULL,
506 				TCA_ACT_NOREPLACE, TCA_ACT_BIND, &err);
507 			if (act == NULL)
508 				return err;
509 
510 			exts->action = act;
511 		}
512 	}
513 #elif defined CONFIG_NET_CLS_POLICE
514 	if (map->police && tb[map->police-1]) {
515 		struct tcf_police *p;
516 
517 		p = tcf_police_locate(tb[map->police-1], rate_tlv);
518 		if (p == NULL)
519 			return -EINVAL;
520 
521 		exts->police = p;
522 	} else if (map->action && tb[map->action-1])
523 		return -EOPNOTSUPP;
524 #else
525 	if ((map->action && tb[map->action-1]) ||
526 	    (map->police && tb[map->police-1]))
527 		return -EOPNOTSUPP;
528 #endif
529 
530 	return 0;
531 }
532 
533 void
534 tcf_exts_change(struct tcf_proto *tp, struct tcf_exts *dst,
535 	        struct tcf_exts *src)
536 {
537 #ifdef CONFIG_NET_CLS_ACT
538 	if (src->action) {
539 		struct tc_action *act;
540 		tcf_tree_lock(tp);
541 		act = xchg(&dst->action, src->action);
542 		tcf_tree_unlock(tp);
543 		if (act)
544 			tcf_action_destroy(act, TCA_ACT_UNBIND);
545 	}
546 #elif defined CONFIG_NET_CLS_POLICE
547 	if (src->police) {
548 		struct tcf_police *p;
549 		tcf_tree_lock(tp);
550 		p = xchg(&dst->police, src->police);
551 		tcf_tree_unlock(tp);
552 		if (p)
553 			tcf_police_release(p, TCA_ACT_UNBIND);
554 	}
555 #endif
556 }
557 
558 int
559 tcf_exts_dump(struct sk_buff *skb, struct tcf_exts *exts,
560 	      struct tcf_ext_map *map)
561 {
562 #ifdef CONFIG_NET_CLS_ACT
563 	if (map->action && exts->action) {
564 		/*
565 		 * again for backward compatible mode - we want
566 		 * to work with both old and new modes of entering
567 		 * tc data even if iproute2  was newer - jhs
568 		 */
569 		struct rtattr * p_rta = (struct rtattr*) skb->tail;
570 
571 		if (exts->action->type != TCA_OLD_COMPAT) {
572 			RTA_PUT(skb, map->action, 0, NULL);
573 			if (tcf_action_dump(skb, exts->action, 0, 0) < 0)
574 				goto rtattr_failure;
575 			p_rta->rta_len = skb->tail - (u8*)p_rta;
576 		} else if (map->police) {
577 			RTA_PUT(skb, map->police, 0, NULL);
578 			if (tcf_action_dump_old(skb, exts->action, 0, 0) < 0)
579 				goto rtattr_failure;
580 			p_rta->rta_len = skb->tail - (u8*)p_rta;
581 		}
582 	}
583 #elif defined CONFIG_NET_CLS_POLICE
584 	if (map->police && exts->police) {
585 		struct rtattr * p_rta = (struct rtattr*) skb->tail;
586 
587 		RTA_PUT(skb, map->police, 0, NULL);
588 
589 		if (tcf_police_dump(skb, exts->police) < 0)
590 			goto rtattr_failure;
591 
592 		p_rta->rta_len = skb->tail - (u8*)p_rta;
593 	}
594 #endif
595 	return 0;
596 rtattr_failure: __attribute__ ((unused))
597 	return -1;
598 }
599 
600 int
601 tcf_exts_dump_stats(struct sk_buff *skb, struct tcf_exts *exts,
602 	            struct tcf_ext_map *map)
603 {
604 #ifdef CONFIG_NET_CLS_ACT
605 	if (exts->action)
606 		if (tcf_action_copy_stats(skb, exts->action, 1) < 0)
607 			goto rtattr_failure;
608 #elif defined CONFIG_NET_CLS_POLICE
609 	if (exts->police)
610 		if (tcf_police_dump_stats(skb, exts->police) < 0)
611 			goto rtattr_failure;
612 #endif
613 	return 0;
614 rtattr_failure: __attribute__ ((unused))
615 	return -1;
616 }
617 
618 static int __init tc_filter_init(void)
619 {
620 	struct rtnetlink_link *link_p = rtnetlink_links[PF_UNSPEC];
621 
622 	/* Setup rtnetlink links. It is made here to avoid
623 	   exporting large number of public symbols.
624 	 */
625 
626 	if (link_p) {
627 		link_p[RTM_NEWTFILTER-RTM_BASE].doit = tc_ctl_tfilter;
628 		link_p[RTM_DELTFILTER-RTM_BASE].doit = tc_ctl_tfilter;
629 		link_p[RTM_GETTFILTER-RTM_BASE].doit = tc_ctl_tfilter;
630 		link_p[RTM_GETTFILTER-RTM_BASE].dumpit = tc_dump_tfilter;
631 	}
632 	return 0;
633 }
634 
635 subsys_initcall(tc_filter_init);
636 
637 EXPORT_SYMBOL(register_tcf_proto_ops);
638 EXPORT_SYMBOL(unregister_tcf_proto_ops);
639 EXPORT_SYMBOL(tcf_exts_validate);
640 EXPORT_SYMBOL(tcf_exts_destroy);
641 EXPORT_SYMBOL(tcf_exts_change);
642 EXPORT_SYMBOL(tcf_exts_dump);
643 EXPORT_SYMBOL(tcf_exts_dump_stats);
644