xref: /kernel/linux/linux-5.10/net/sched/cls_route.c (revision 8c2ecf20) 
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * net/sched/cls_route.c	ROUTE4 classifier.
4 *
5 * Authors:	Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
6 */
7
8#include <linux/module.h>
9#include <linux/slab.h>
10#include <linux/types.h>
11#include <linux/kernel.h>
12#include <linux/string.h>
13#include <linux/errno.h>
14#include <linux/skbuff.h>
15#include <net/dst.h>
16#include <net/route.h>
17#include <net/netlink.h>
18#include <net/act_api.h>
19#include <net/pkt_cls.h>
20
21/*
22 * 1. For now we assume that route tags < 256.
23 *    It allows to use direct table lookups, instead of hash tables.
24 * 2. For now we assume that "from TAG" and "fromdev DEV" statements
25 *    are mutually  exclusive.
26 * 3. "to TAG from ANY" has higher priority, than "to ANY from XXX"
27 */
28struct route4_fastmap {
29	struct route4_filter		*filter;
30	u32				id;
31	int				iif;
32};
33
34struct route4_head {
35	struct route4_fastmap		fastmap[16];
36	struct route4_bucket __rcu	*table[256 + 1];
37	struct rcu_head			rcu;
38};
39
40struct route4_bucket {
41	/* 16 FROM buckets + 16 IIF buckets + 1 wildcard bucket */
42	struct route4_filter __rcu	*ht[16 + 16 + 1];
43	struct rcu_head			rcu;
44};
45
46struct route4_filter {
47	struct route4_filter __rcu	*next;
48	u32			id;
49	int			iif;
50
51	struct tcf_result	res;
52	struct tcf_exts		exts;
53	u32			handle;
54	struct route4_bucket	*bkt;
55	struct tcf_proto	*tp;
56	struct rcu_work		rwork;
57};
58
59#define ROUTE4_FAILURE ((struct route4_filter *)(-1L))
60
61static inline int route4_fastmap_hash(u32 id, int iif)
62{
63	return id & 0xF;
64}
65
66static DEFINE_SPINLOCK(fastmap_lock);
67static void
68route4_reset_fastmap(struct route4_head *head)
69{
70	spin_lock_bh(&fastmap_lock);
71	memset(head->fastmap, 0, sizeof(head->fastmap));
72	spin_unlock_bh(&fastmap_lock);
73}
74
75static void
76route4_set_fastmap(struct route4_head *head, u32 id, int iif,
77		   struct route4_filter *f)
78{
79	int h = route4_fastmap_hash(id, iif);
80
81	/* fastmap updates must look atomic to aling id, iff, filter */
82	spin_lock_bh(&fastmap_lock);
83	head->fastmap[h].id = id;
84	head->fastmap[h].iif = iif;
85	head->fastmap[h].filter = f;
86	spin_unlock_bh(&fastmap_lock);
87}
88
89static inline int route4_hash_to(u32 id)
90{
91	return id & 0xFF;
92}
93
94static inline int route4_hash_from(u32 id)
95{
96	return (id >> 16) & 0xF;
97}
98
99static inline int route4_hash_iif(int iif)
100{
101	return 16 + ((iif >> 16) & 0xF);
102}
103
104static inline int route4_hash_wild(void)
105{
106	return 32;
107}
108
109#define ROUTE4_APPLY_RESULT()					\
110{								\
111	*res = f->res;						\
112	if (tcf_exts_has_actions(&f->exts)) {			\
113		int r = tcf_exts_exec(skb, &f->exts, res);	\
114		if (r < 0) {					\
115			dont_cache = 1;				\
116			continue;				\
117		}						\
118		return r;					\
119	} else if (!dont_cache)					\
120		route4_set_fastmap(head, id, iif, f);		\
121	return 0;						\
122}
123
124static int route4_classify(struct sk_buff *skb, const struct tcf_proto *tp,
125			   struct tcf_result *res)
126{
127	struct route4_head *head = rcu_dereference_bh(tp->root);
128	struct dst_entry *dst;
129	struct route4_bucket *b;
130	struct route4_filter *f;
131	u32 id, h;
132	int iif, dont_cache = 0;
133
134	dst = skb_dst(skb);
135	if (!dst)
136		goto failure;
137
138	id = dst->tclassid;
139
140	iif = inet_iif(skb);
141
142	h = route4_fastmap_hash(id, iif);
143
144	spin_lock(&fastmap_lock);
145	if (id == head->fastmap[h].id &&
146	    iif == head->fastmap[h].iif &&
147	    (f = head->fastmap[h].filter) != NULL) {
148		if (f == ROUTE4_FAILURE) {
149			spin_unlock(&fastmap_lock);
150			goto failure;
151		}
152
153		*res = f->res;
154		spin_unlock(&fastmap_lock);
155		return 0;
156	}
157	spin_unlock(&fastmap_lock);
158
159	h = route4_hash_to(id);
160
161restart:
162	b = rcu_dereference_bh(head->table[h]);
163	if (b) {
164		for (f = rcu_dereference_bh(b->ht[route4_hash_from(id)]);
165		     f;
166		     f = rcu_dereference_bh(f->next))
167			if (f->id == id)
168				ROUTE4_APPLY_RESULT();
169
170		for (f = rcu_dereference_bh(b->ht[route4_hash_iif(iif)]);
171		     f;
172		     f = rcu_dereference_bh(f->next))
173			if (f->iif == iif)
174				ROUTE4_APPLY_RESULT();
175
176		for (f = rcu_dereference_bh(b->ht[route4_hash_wild()]);
177		     f;
178		     f = rcu_dereference_bh(f->next))
179			ROUTE4_APPLY_RESULT();
180	}
181	if (h < 256) {
182		h = 256;
183		id &= ~0xFFFF;
184		goto restart;
185	}
186
187	if (!dont_cache)
188		route4_set_fastmap(head, id, iif, ROUTE4_FAILURE);
189failure:
190	return -1;
191}
192
193static inline u32 to_hash(u32 id)
194{
195	u32 h = id & 0xFF;
196
197	if (id & 0x8000)
198		h += 256;
199	return h;
200}
201
202static inline u32 from_hash(u32 id)
203{
204	id &= 0xFFFF;
205	if (id == 0xFFFF)
206		return 32;
207	if (!(id & 0x8000)) {
208		if (id > 255)
209			return 256;
210		return id & 0xF;
211	}
212	return 16 + (id & 0xF);
213}
214
215static void *route4_get(struct tcf_proto *tp, u32 handle)
216{
217	struct route4_head *head = rtnl_dereference(tp->root);
218	struct route4_bucket *b;
219	struct route4_filter *f;
220	unsigned int h1, h2;
221
222	h1 = to_hash(handle);
223	if (h1 > 256)
224		return NULL;
225
226	h2 = from_hash(handle >> 16);
227	if (h2 > 32)
228		return NULL;
229
230	b = rtnl_dereference(head->table[h1]);
231	if (b) {
232		for (f = rtnl_dereference(b->ht[h2]);
233		     f;
234		     f = rtnl_dereference(f->next))
235			if (f->handle == handle)
236				return f;
237	}
238	return NULL;
239}
240
241static int route4_init(struct tcf_proto *tp)
242{
243	struct route4_head *head;
244
245	head = kzalloc(sizeof(struct route4_head), GFP_KERNEL);
246	if (head == NULL)
247		return -ENOBUFS;
248
249	rcu_assign_pointer(tp->root, head);
250	return 0;
251}
252
253static void __route4_delete_filter(struct route4_filter *f)
254{
255	tcf_exts_destroy(&f->exts);
256	tcf_exts_put_net(&f->exts);
257	kfree(f);
258}
259
260static void route4_delete_filter_work(struct work_struct *work)
261{
262	struct route4_filter *f = container_of(to_rcu_work(work),
263					       struct route4_filter,
264					       rwork);
265	rtnl_lock();
266	__route4_delete_filter(f);
267	rtnl_unlock();
268}
269
270static void route4_queue_work(struct route4_filter *f)
271{
272	tcf_queue_work(&f->rwork, route4_delete_filter_work);
273}
274
275static void route4_destroy(struct tcf_proto *tp, bool rtnl_held,
276			   struct netlink_ext_ack *extack)
277{
278	struct route4_head *head = rtnl_dereference(tp->root);
279	int h1, h2;
280
281	if (head == NULL)
282		return;
283
284	for (h1 = 0; h1 <= 256; h1++) {
285		struct route4_bucket *b;
286
287		b = rtnl_dereference(head->table[h1]);
288		if (b) {
289			for (h2 = 0; h2 <= 32; h2++) {
290				struct route4_filter *f;
291
292				while ((f = rtnl_dereference(b->ht[h2])) != NULL) {
293					struct route4_filter *next;
294
295					next = rtnl_dereference(f->next);
296					RCU_INIT_POINTER(b->ht[h2], next);
297					tcf_unbind_filter(tp, &f->res);
298					if (tcf_exts_get_net(&f->exts))
299						route4_queue_work(f);
300					else
301						__route4_delete_filter(f);
302				}
303			}
304			RCU_INIT_POINTER(head->table[h1], NULL);
305			kfree_rcu(b, rcu);
306		}
307	}
308	kfree_rcu(head, rcu);
309}
310
311static int route4_delete(struct tcf_proto *tp, void *arg, bool *last,
312			 bool rtnl_held, struct netlink_ext_ack *extack)
313{
314	struct route4_head *head = rtnl_dereference(tp->root);
315	struct route4_filter *f = arg;
316	struct route4_filter __rcu **fp;
317	struct route4_filter *nf;
318	struct route4_bucket *b;
319	unsigned int h = 0;
320	int i, h1;
321
322	if (!head || !f)
323		return -EINVAL;
324
325	h = f->handle;
326	b = f->bkt;
327
328	fp = &b->ht[from_hash(h >> 16)];
329	for (nf = rtnl_dereference(*fp); nf;
330	     fp = &nf->next, nf = rtnl_dereference(*fp)) {
331		if (nf == f) {
332			/* unlink it */
333			RCU_INIT_POINTER(*fp, rtnl_dereference(f->next));
334
335			/* Remove any fastmap lookups that might ref filter
336			 * notice we unlink'd the filter so we can't get it
337			 * back in the fastmap.
338			 */
339			route4_reset_fastmap(head);
340
341			/* Delete it */
342			tcf_unbind_filter(tp, &f->res);
343			tcf_exts_get_net(&f->exts);
344			tcf_queue_work(&f->rwork, route4_delete_filter_work);
345
346			/* Strip RTNL protected tree */
347			for (i = 0; i <= 32; i++) {
348				struct route4_filter *rt;
349
350				rt = rtnl_dereference(b->ht[i]);
351				if (rt)
352					goto out;
353			}
354
355			/* OK, session has no flows */
356			RCU_INIT_POINTER(head->table[to_hash(h)], NULL);
357			kfree_rcu(b, rcu);
358			break;
359		}
360	}
361
362out:
363	*last = true;
364	for (h1 = 0; h1 <= 256; h1++) {
365		if (rcu_access_pointer(head->table[h1])) {
366			*last = false;
367			break;
368		}
369	}
370
371	return 0;
372}
373
374static const struct nla_policy route4_policy[TCA_ROUTE4_MAX + 1] = {
375	[TCA_ROUTE4_CLASSID]	= { .type = NLA_U32 },
376	[TCA_ROUTE4_TO]		= { .type = NLA_U32 },
377	[TCA_ROUTE4_FROM]	= { .type = NLA_U32 },
378	[TCA_ROUTE4_IIF]	= { .type = NLA_U32 },
379};
380
381static int route4_set_parms(struct net *net, struct tcf_proto *tp,
382			    unsigned long base, struct route4_filter *f,
383			    u32 handle, struct route4_head *head,
384			    struct nlattr **tb, struct nlattr *est, int new,
385			    bool ovr, struct netlink_ext_ack *extack)
386{
387	u32 id = 0, to = 0, nhandle = 0x8000;
388	struct route4_filter *fp;
389	unsigned int h1;
390	struct route4_bucket *b;
391	int err;
392
393	err = tcf_exts_validate(net, tp, tb, est, &f->exts, ovr, true, extack);
394	if (err < 0)
395		return err;
396
397	if (tb[TCA_ROUTE4_TO]) {
398		if (new && handle & 0x8000)
399			return -EINVAL;
400		to = nla_get_u32(tb[TCA_ROUTE4_TO]);
401		if (to > 0xFF)
402			return -EINVAL;
403		nhandle = to;
404	}
405
406	if (tb[TCA_ROUTE4_FROM]) {
407		if (tb[TCA_ROUTE4_IIF])
408			return -EINVAL;
409		id = nla_get_u32(tb[TCA_ROUTE4_FROM]);
410		if (id > 0xFF)
411			return -EINVAL;
412		nhandle |= id << 16;
413	} else if (tb[TCA_ROUTE4_IIF]) {
414		id = nla_get_u32(tb[TCA_ROUTE4_IIF]);
415		if (id > 0x7FFF)
416			return -EINVAL;
417		nhandle |= (id | 0x8000) << 16;
418	} else
419		nhandle |= 0xFFFF << 16;
420
421	if (handle && new) {
422		nhandle |= handle & 0x7F00;
423		if (nhandle != handle)
424			return -EINVAL;
425	}
426
427	if (!nhandle) {
428		NL_SET_ERR_MSG(extack, "Replacing with handle of 0 is invalid");
429		return -EINVAL;
430	}
431
432	h1 = to_hash(nhandle);
433	b = rtnl_dereference(head->table[h1]);
434	if (!b) {
435		b = kzalloc(sizeof(struct route4_bucket), GFP_KERNEL);
436		if (b == NULL)
437			return -ENOBUFS;
438
439		rcu_assign_pointer(head->table[h1], b);
440	} else {
441		unsigned int h2 = from_hash(nhandle >> 16);
442
443		for (fp = rtnl_dereference(b->ht[h2]);
444		     fp;
445		     fp = rtnl_dereference(fp->next))
446			if (fp->handle == f->handle)
447				return -EEXIST;
448	}
449
450	if (tb[TCA_ROUTE4_TO])
451		f->id = to;
452
453	if (tb[TCA_ROUTE4_FROM])
454		f->id = to | id<<16;
455	else if (tb[TCA_ROUTE4_IIF])
456		f->iif = id;
457
458	f->handle = nhandle;
459	f->bkt = b;
460	f->tp = tp;
461
462	if (tb[TCA_ROUTE4_CLASSID]) {
463		f->res.classid = nla_get_u32(tb[TCA_ROUTE4_CLASSID]);
464		tcf_bind_filter(tp, &f->res, base);
465	}
466
467	return 0;
468}
469
470static int route4_change(struct net *net, struct sk_buff *in_skb,
471			 struct tcf_proto *tp, unsigned long base, u32 handle,
472			 struct nlattr **tca, void **arg, bool ovr,
473			 bool rtnl_held, struct netlink_ext_ack *extack)
474{
475	struct route4_head *head = rtnl_dereference(tp->root);
476	struct route4_filter __rcu **fp;
477	struct route4_filter *fold, *f1, *pfp, *f = NULL;
478	struct route4_bucket *b;
479	struct nlattr *opt = tca[TCA_OPTIONS];
480	struct nlattr *tb[TCA_ROUTE4_MAX + 1];
481	unsigned int h, th;
482	int err;
483	bool new = true;
484
485	if (!handle) {
486		NL_SET_ERR_MSG(extack, "Creating with handle of 0 is invalid");
487		return -EINVAL;
488	}
489
490	if (opt == NULL)
491		return handle ? -EINVAL : 0;
492
493	err = nla_parse_nested_deprecated(tb, TCA_ROUTE4_MAX, opt,
494					  route4_policy, NULL);
495	if (err < 0)
496		return err;
497
498	fold = *arg;
499	if (fold && handle && fold->handle != handle)
500			return -EINVAL;
501
502	err = -ENOBUFS;
503	f = kzalloc(sizeof(struct route4_filter), GFP_KERNEL);
504	if (!f)
505		goto errout;
506
507	err = tcf_exts_init(&f->exts, net, TCA_ROUTE4_ACT, TCA_ROUTE4_POLICE);
508	if (err < 0)
509		goto errout;
510
511	if (fold) {
512		f->id = fold->id;
513		f->iif = fold->iif;
514		f->handle = fold->handle;
515
516		f->tp = fold->tp;
517		f->bkt = fold->bkt;
518		new = false;
519	}
520
521	err = route4_set_parms(net, tp, base, f, handle, head, tb,
522			       tca[TCA_RATE], new, ovr, extack);
523	if (err < 0)
524		goto errout;
525
526	h = from_hash(f->handle >> 16);
527	fp = &f->bkt->ht[h];
528	for (pfp = rtnl_dereference(*fp);
529	     (f1 = rtnl_dereference(*fp)) != NULL;
530	     fp = &f1->next)
531		if (f->handle < f1->handle)
532			break;
533
534	tcf_block_netif_keep_dst(tp->chain->block);
535	rcu_assign_pointer(f->next, f1);
536	rcu_assign_pointer(*fp, f);
537
538	if (fold) {
539		th = to_hash(fold->handle);
540		h = from_hash(fold->handle >> 16);
541		b = rtnl_dereference(head->table[th]);
542		if (b) {
543			fp = &b->ht[h];
544			for (pfp = rtnl_dereference(*fp); pfp;
545			     fp = &pfp->next, pfp = rtnl_dereference(*fp)) {
546				if (pfp == fold) {
547					rcu_assign_pointer(*fp, fold->next);
548					break;
549				}
550			}
551		}
552	}
553
554	route4_reset_fastmap(head);
555	*arg = f;
556	if (fold) {
557		tcf_unbind_filter(tp, &fold->res);
558		tcf_exts_get_net(&fold->exts);
559		tcf_queue_work(&fold->rwork, route4_delete_filter_work);
560	}
561	return 0;
562
563errout:
564	if (f)
565		tcf_exts_destroy(&f->exts);
566	kfree(f);
567	return err;
568}
569
570static void route4_walk(struct tcf_proto *tp, struct tcf_walker *arg,
571			bool rtnl_held)
572{
573	struct route4_head *head = rtnl_dereference(tp->root);
574	unsigned int h, h1;
575
576	if (head == NULL || arg->stop)
577		return;
578
579	for (h = 0; h <= 256; h++) {
580		struct route4_bucket *b = rtnl_dereference(head->table[h]);
581
582		if (b) {
583			for (h1 = 0; h1 <= 32; h1++) {
584				struct route4_filter *f;
585
586				for (f = rtnl_dereference(b->ht[h1]);
587				     f;
588				     f = rtnl_dereference(f->next)) {
589					if (arg->count < arg->skip) {
590						arg->count++;
591						continue;
592					}
593					if (arg->fn(tp, f, arg) < 0) {
594						arg->stop = 1;
595						return;
596					}
597					arg->count++;
598				}
599			}
600		}
601	}
602}
603
604static int route4_dump(struct net *net, struct tcf_proto *tp, void *fh,
605		       struct sk_buff *skb, struct tcmsg *t, bool rtnl_held)
606{
607	struct route4_filter *f = fh;
608	struct nlattr *nest;
609	u32 id;
610
611	if (f == NULL)
612		return skb->len;
613
614	t->tcm_handle = f->handle;
615
616	nest = nla_nest_start_noflag(skb, TCA_OPTIONS);
617	if (nest == NULL)
618		goto nla_put_failure;
619
620	if (!(f->handle & 0x8000)) {
621		id = f->id & 0xFF;
622		if (nla_put_u32(skb, TCA_ROUTE4_TO, id))
623			goto nla_put_failure;
624	}
625	if (f->handle & 0x80000000) {
626		if ((f->handle >> 16) != 0xFFFF &&
627		    nla_put_u32(skb, TCA_ROUTE4_IIF, f->iif))
628			goto nla_put_failure;
629	} else {
630		id = f->id >> 16;
631		if (nla_put_u32(skb, TCA_ROUTE4_FROM, id))
632			goto nla_put_failure;
633	}
634	if (f->res.classid &&
635	    nla_put_u32(skb, TCA_ROUTE4_CLASSID, f->res.classid))
636		goto nla_put_failure;
637
638	if (tcf_exts_dump(skb, &f->exts) < 0)
639		goto nla_put_failure;
640
641	nla_nest_end(skb, nest);
642
643	if (tcf_exts_dump_stats(skb, &f->exts) < 0)
644		goto nla_put_failure;
645
646	return skb->len;
647
648nla_put_failure:
649	nla_nest_cancel(skb, nest);
650	return -1;
651}
652
653static void route4_bind_class(void *fh, u32 classid, unsigned long cl, void *q,
654			      unsigned long base)
655{
656	struct route4_filter *f = fh;
657
658	if (f && f->res.classid == classid) {
659		if (cl)
660			__tcf_bind_filter(q, &f->res, base);
661		else
662			__tcf_unbind_filter(q, &f->res);
663	}
664}
665
666static struct tcf_proto_ops cls_route4_ops __read_mostly = {
667	.kind		=	"route",
668	.classify	=	route4_classify,
669	.init		=	route4_init,
670	.destroy	=	route4_destroy,
671	.get		=	route4_get,
672	.change		=	route4_change,
673	.delete		=	route4_delete,
674	.walk		=	route4_walk,
675	.dump		=	route4_dump,
676	.bind_class	=	route4_bind_class,
677	.owner		=	THIS_MODULE,
678};
679
680static int __init init_route4(void)
681{
682	return register_tcf_proto_ops(&cls_route4_ops);
683}
684
685static void __exit exit_route4(void)
686{
687	unregister_tcf_proto_ops(&cls_route4_ops);
688}
689
690module_init(init_route4)
691module_exit(exit_route4)
692MODULE_LICENSE("GPL");
693