xref: /kernel/linux/linux-6.6/net/sched/cls_route.c (revision 62306a36) 
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#include <net/tc_wrapper.h>
21
22/*
23 * 1. For now we assume that route tags < 256.
24 *    It allows to use direct table lookups, instead of hash tables.
25 * 2. For now we assume that "from TAG" and "fromdev DEV" statements
26 *    are mutually  exclusive.
27 * 3. "to TAG from ANY" has higher priority, than "to ANY from XXX"
28 */
29struct route4_fastmap {
30	struct route4_filter		*filter;
31	u32				id;
32	int				iif;
33};
34
35struct route4_head {
36	struct route4_fastmap		fastmap[16];
37	struct route4_bucket __rcu	*table[256 + 1];
38	struct rcu_head			rcu;
39};
40
41struct route4_bucket {
42	/* 16 FROM buckets + 16 IIF buckets + 1 wildcard bucket */
43	struct route4_filter __rcu	*ht[16 + 16 + 1];
44	struct rcu_head			rcu;
45};
46
47struct route4_filter {
48	struct route4_filter __rcu	*next;
49	u32			id;
50	int			iif;
51
52	struct tcf_result	res;
53	struct tcf_exts		exts;
54	u32			handle;
55	struct route4_bucket	*bkt;
56	struct tcf_proto	*tp;
57	struct rcu_work		rwork;
58};
59
60#define ROUTE4_FAILURE ((struct route4_filter *)(-1L))
61
62static inline int route4_fastmap_hash(u32 id, int iif)
63{
64	return id & 0xF;
65}
66
67static DEFINE_SPINLOCK(fastmap_lock);
68static void
69route4_reset_fastmap(struct route4_head *head)
70{
71	spin_lock_bh(&fastmap_lock);
72	memset(head->fastmap, 0, sizeof(head->fastmap));
73	spin_unlock_bh(&fastmap_lock);
74}
75
76static void
77route4_set_fastmap(struct route4_head *head, u32 id, int iif,
78		   struct route4_filter *f)
79{
80	int h = route4_fastmap_hash(id, iif);
81
82	/* fastmap updates must look atomic to aling id, iff, filter */
83	spin_lock_bh(&fastmap_lock);
84	head->fastmap[h].id = id;
85	head->fastmap[h].iif = iif;
86	head->fastmap[h].filter = f;
87	spin_unlock_bh(&fastmap_lock);
88}
89
90static inline int route4_hash_to(u32 id)
91{
92	return id & 0xFF;
93}
94
95static inline int route4_hash_from(u32 id)
96{
97	return (id >> 16) & 0xF;
98}
99
100static inline int route4_hash_iif(int iif)
101{
102	return 16 + ((iif >> 16) & 0xF);
103}
104
105static inline int route4_hash_wild(void)
106{
107	return 32;
108}
109
110#define ROUTE4_APPLY_RESULT()					\
111{								\
112	*res = f->res;						\
113	if (tcf_exts_has_actions(&f->exts)) {			\
114		int r = tcf_exts_exec(skb, &f->exts, res);	\
115		if (r < 0) {					\
116			dont_cache = 1;				\
117			continue;				\
118		}						\
119		return r;					\
120	} else if (!dont_cache)					\
121		route4_set_fastmap(head, id, iif, f);		\
122	return 0;						\
123}
124
125TC_INDIRECT_SCOPE int route4_classify(struct sk_buff *skb,
126				      const struct tcf_proto *tp,
127				      struct tcf_result *res)
128{
129	struct route4_head *head = rcu_dereference_bh(tp->root);
130	struct dst_entry *dst;
131	struct route4_bucket *b;
132	struct route4_filter *f;
133	u32 id, h;
134	int iif, dont_cache = 0;
135
136	dst = skb_dst(skb);
137	if (!dst)
138		goto failure;
139
140	id = dst->tclassid;
141
142	iif = inet_iif(skb);
143
144	h = route4_fastmap_hash(id, iif);
145
146	spin_lock(&fastmap_lock);
147	if (id == head->fastmap[h].id &&
148	    iif == head->fastmap[h].iif &&
149	    (f = head->fastmap[h].filter) != NULL) {
150		if (f == ROUTE4_FAILURE) {
151			spin_unlock(&fastmap_lock);
152			goto failure;
153		}
154
155		*res = f->res;
156		spin_unlock(&fastmap_lock);
157		return 0;
158	}
159	spin_unlock(&fastmap_lock);
160
161	h = route4_hash_to(id);
162
163restart:
164	b = rcu_dereference_bh(head->table[h]);
165	if (b) {
166		for (f = rcu_dereference_bh(b->ht[route4_hash_from(id)]);
167		     f;
168		     f = rcu_dereference_bh(f->next))
169			if (f->id == id)
170				ROUTE4_APPLY_RESULT();
171
172		for (f = rcu_dereference_bh(b->ht[route4_hash_iif(iif)]);
173		     f;
174		     f = rcu_dereference_bh(f->next))
175			if (f->iif == iif)
176				ROUTE4_APPLY_RESULT();
177
178		for (f = rcu_dereference_bh(b->ht[route4_hash_wild()]);
179		     f;
180		     f = rcu_dereference_bh(f->next))
181			ROUTE4_APPLY_RESULT();
182	}
183	if (h < 256) {
184		h = 256;
185		id &= ~0xFFFF;
186		goto restart;
187	}
188
189	if (!dont_cache)
190		route4_set_fastmap(head, id, iif, ROUTE4_FAILURE);
191failure:
192	return -1;
193}
194
195static inline u32 to_hash(u32 id)
196{
197	u32 h = id & 0xFF;
198
199	if (id & 0x8000)
200		h += 256;
201	return h;
202}
203
204static inline u32 from_hash(u32 id)
205{
206	id &= 0xFFFF;
207	if (id == 0xFFFF)
208		return 32;
209	if (!(id & 0x8000)) {
210		if (id > 255)
211			return 256;
212		return id & 0xF;
213	}
214	return 16 + (id & 0xF);
215}
216
217static void *route4_get(struct tcf_proto *tp, u32 handle)
218{
219	struct route4_head *head = rtnl_dereference(tp->root);
220	struct route4_bucket *b;
221	struct route4_filter *f;
222	unsigned int h1, h2;
223
224	h1 = to_hash(handle);
225	if (h1 > 256)
226		return NULL;
227
228	h2 = from_hash(handle >> 16);
229	if (h2 > 32)
230		return NULL;
231
232	b = rtnl_dereference(head->table[h1]);
233	if (b) {
234		for (f = rtnl_dereference(b->ht[h2]);
235		     f;
236		     f = rtnl_dereference(f->next))
237			if (f->handle == handle)
238				return f;
239	}
240	return NULL;
241}
242
243static int route4_init(struct tcf_proto *tp)
244{
245	struct route4_head *head;
246
247	head = kzalloc(sizeof(struct route4_head), GFP_KERNEL);
248	if (head == NULL)
249		return -ENOBUFS;
250
251	rcu_assign_pointer(tp->root, head);
252	return 0;
253}
254
255static void __route4_delete_filter(struct route4_filter *f)
256{
257	tcf_exts_destroy(&f->exts);
258	tcf_exts_put_net(&f->exts);
259	kfree(f);
260}
261
262static void route4_delete_filter_work(struct work_struct *work)
263{
264	struct route4_filter *f = container_of(to_rcu_work(work),
265					       struct route4_filter,
266					       rwork);
267	rtnl_lock();
268	__route4_delete_filter(f);
269	rtnl_unlock();
270}
271
272static void route4_queue_work(struct route4_filter *f)
273{
274	tcf_queue_work(&f->rwork, route4_delete_filter_work);
275}
276
277static void route4_destroy(struct tcf_proto *tp, bool rtnl_held,
278			   struct netlink_ext_ack *extack)
279{
280	struct route4_head *head = rtnl_dereference(tp->root);
281	int h1, h2;
282
283	if (head == NULL)
284		return;
285
286	for (h1 = 0; h1 <= 256; h1++) {
287		struct route4_bucket *b;
288
289		b = rtnl_dereference(head->table[h1]);
290		if (b) {
291			for (h2 = 0; h2 <= 32; h2++) {
292				struct route4_filter *f;
293
294				while ((f = rtnl_dereference(b->ht[h2])) != NULL) {
295					struct route4_filter *next;
296
297					next = rtnl_dereference(f->next);
298					RCU_INIT_POINTER(b->ht[h2], next);
299					tcf_unbind_filter(tp, &f->res);
300					if (tcf_exts_get_net(&f->exts))
301						route4_queue_work(f);
302					else
303						__route4_delete_filter(f);
304				}
305			}
306			RCU_INIT_POINTER(head->table[h1], NULL);
307			kfree_rcu(b, rcu);
308		}
309	}
310	kfree_rcu(head, rcu);
311}
312
313static int route4_delete(struct tcf_proto *tp, void *arg, bool *last,
314			 bool rtnl_held, struct netlink_ext_ack *extack)
315{
316	struct route4_head *head = rtnl_dereference(tp->root);
317	struct route4_filter *f = arg;
318	struct route4_filter __rcu **fp;
319	struct route4_filter *nf;
320	struct route4_bucket *b;
321	unsigned int h = 0;
322	int i, h1;
323
324	if (!head || !f)
325		return -EINVAL;
326
327	h = f->handle;
328	b = f->bkt;
329
330	fp = &b->ht[from_hash(h >> 16)];
331	for (nf = rtnl_dereference(*fp); nf;
332	     fp = &nf->next, nf = rtnl_dereference(*fp)) {
333		if (nf == f) {
334			/* unlink it */
335			RCU_INIT_POINTER(*fp, rtnl_dereference(f->next));
336
337			/* Remove any fastmap lookups that might ref filter
338			 * notice we unlink'd the filter so we can't get it
339			 * back in the fastmap.
340			 */
341			route4_reset_fastmap(head);
342
343			/* Delete it */
344			tcf_unbind_filter(tp, &f->res);
345			tcf_exts_get_net(&f->exts);
346			tcf_queue_work(&f->rwork, route4_delete_filter_work);
347
348			/* Strip RTNL protected tree */
349			for (i = 0; i <= 32; i++) {
350				struct route4_filter *rt;
351
352				rt = rtnl_dereference(b->ht[i]);
353				if (rt)
354					goto out;
355			}
356
357			/* OK, session has no flows */
358			RCU_INIT_POINTER(head->table[to_hash(h)], NULL);
359			kfree_rcu(b, rcu);
360			break;
361		}
362	}
363
364out:
365	*last = true;
366	for (h1 = 0; h1 <= 256; h1++) {
367		if (rcu_access_pointer(head->table[h1])) {
368			*last = false;
369			break;
370		}
371	}
372
373	return 0;
374}
375
376static const struct nla_policy route4_policy[TCA_ROUTE4_MAX + 1] = {
377	[TCA_ROUTE4_CLASSID]	= { .type = NLA_U32 },
378	[TCA_ROUTE4_TO]		= { .type = NLA_U32 },
379	[TCA_ROUTE4_FROM]	= { .type = NLA_U32 },
380	[TCA_ROUTE4_IIF]	= { .type = NLA_U32 },
381};
382
383static int route4_set_parms(struct net *net, struct tcf_proto *tp,
384			    unsigned long base, struct route4_filter *f,
385			    u32 handle, struct route4_head *head,
386			    struct nlattr **tb, struct nlattr *est, int new,
387			    u32 flags, struct netlink_ext_ack *extack)
388{
389	u32 id = 0, to = 0, nhandle = 0x8000;
390	struct route4_filter *fp;
391	unsigned int h1;
392	struct route4_bucket *b;
393	int err;
394
395	err = tcf_exts_validate(net, tp, tb, est, &f->exts, flags, extack);
396	if (err < 0)
397		return err;
398
399	if (tb[TCA_ROUTE4_TO]) {
400		if (new && handle & 0x8000)
401			return -EINVAL;
402		to = nla_get_u32(tb[TCA_ROUTE4_TO]);
403		if (to > 0xFF)
404			return -EINVAL;
405		nhandle = to;
406	}
407
408	if (tb[TCA_ROUTE4_FROM]) {
409		if (tb[TCA_ROUTE4_IIF])
410			return -EINVAL;
411		id = nla_get_u32(tb[TCA_ROUTE4_FROM]);
412		if (id > 0xFF)
413			return -EINVAL;
414		nhandle |= id << 16;
415	} else if (tb[TCA_ROUTE4_IIF]) {
416		id = nla_get_u32(tb[TCA_ROUTE4_IIF]);
417		if (id > 0x7FFF)
418			return -EINVAL;
419		nhandle |= (id | 0x8000) << 16;
420	} else
421		nhandle |= 0xFFFF << 16;
422
423	if (handle && new) {
424		nhandle |= handle & 0x7F00;
425		if (nhandle != handle)
426			return -EINVAL;
427	}
428
429	if (!nhandle) {
430		NL_SET_ERR_MSG(extack, "Replacing with handle of 0 is invalid");
431		return -EINVAL;
432	}
433
434	h1 = to_hash(nhandle);
435	b = rtnl_dereference(head->table[h1]);
436	if (!b) {
437		b = kzalloc(sizeof(struct route4_bucket), GFP_KERNEL);
438		if (b == NULL)
439			return -ENOBUFS;
440
441		rcu_assign_pointer(head->table[h1], b);
442	} else {
443		unsigned int h2 = from_hash(nhandle >> 16);
444
445		for (fp = rtnl_dereference(b->ht[h2]);
446		     fp;
447		     fp = rtnl_dereference(fp->next))
448			if (fp->handle == f->handle)
449				return -EEXIST;
450	}
451
452	if (tb[TCA_ROUTE4_TO])
453		f->id = to;
454
455	if (tb[TCA_ROUTE4_FROM])
456		f->id = to | id<<16;
457	else if (tb[TCA_ROUTE4_IIF])
458		f->iif = id;
459
460	f->handle = nhandle;
461	f->bkt = b;
462	f->tp = tp;
463
464	if (tb[TCA_ROUTE4_CLASSID]) {
465		f->res.classid = nla_get_u32(tb[TCA_ROUTE4_CLASSID]);
466		tcf_bind_filter(tp, &f->res, base);
467	}
468
469	return 0;
470}
471
472static int route4_change(struct net *net, struct sk_buff *in_skb,
473			 struct tcf_proto *tp, unsigned long base, u32 handle,
474			 struct nlattr **tca, void **arg, u32 flags,
475			 struct netlink_ext_ack *extack)
476{
477	struct route4_head *head = rtnl_dereference(tp->root);
478	struct route4_filter __rcu **fp;
479	struct route4_filter *fold, *f1, *pfp, *f = NULL;
480	struct route4_bucket *b;
481	struct nlattr *opt = tca[TCA_OPTIONS];
482	struct nlattr *tb[TCA_ROUTE4_MAX + 1];
483	unsigned int h, th;
484	int err;
485	bool new = true;
486
487	if (!handle) {
488		NL_SET_ERR_MSG(extack, "Creating with handle of 0 is invalid");
489		return -EINVAL;
490	}
491
492	if (opt == NULL)
493		return -EINVAL;
494
495	err = nla_parse_nested_deprecated(tb, TCA_ROUTE4_MAX, opt,
496					  route4_policy, NULL);
497	if (err < 0)
498		return err;
499
500	fold = *arg;
501	if (fold && fold->handle != handle)
502			return -EINVAL;
503
504	err = -ENOBUFS;
505	f = kzalloc(sizeof(struct route4_filter), GFP_KERNEL);
506	if (!f)
507		goto errout;
508
509	err = tcf_exts_init(&f->exts, net, TCA_ROUTE4_ACT, TCA_ROUTE4_POLICE);
510	if (err < 0)
511		goto errout;
512
513	if (fold) {
514		f->id = fold->id;
515		f->iif = fold->iif;
516		f->handle = fold->handle;
517
518		f->tp = fold->tp;
519		f->bkt = fold->bkt;
520		new = false;
521	}
522
523	err = route4_set_parms(net, tp, base, f, handle, head, tb,
524			       tca[TCA_RATE], new, flags, extack);
525	if (err < 0)
526		goto errout;
527
528	h = from_hash(f->handle >> 16);
529	fp = &f->bkt->ht[h];
530	for (pfp = rtnl_dereference(*fp);
531	     (f1 = rtnl_dereference(*fp)) != NULL;
532	     fp = &f1->next)
533		if (f->handle < f1->handle)
534			break;
535
536	tcf_block_netif_keep_dst(tp->chain->block);
537	rcu_assign_pointer(f->next, f1);
538	rcu_assign_pointer(*fp, f);
539
540	if (fold) {
541		th = to_hash(fold->handle);
542		h = from_hash(fold->handle >> 16);
543		b = rtnl_dereference(head->table[th]);
544		if (b) {
545			fp = &b->ht[h];
546			for (pfp = rtnl_dereference(*fp); pfp;
547			     fp = &pfp->next, pfp = rtnl_dereference(*fp)) {
548				if (pfp == fold) {
549					rcu_assign_pointer(*fp, fold->next);
550					break;
551				}
552			}
553		}
554	}
555
556	route4_reset_fastmap(head);
557	*arg = f;
558	if (fold) {
559		tcf_unbind_filter(tp, &fold->res);
560		tcf_exts_get_net(&fold->exts);
561		tcf_queue_work(&fold->rwork, route4_delete_filter_work);
562	}
563	return 0;
564
565errout:
566	if (f)
567		tcf_exts_destroy(&f->exts);
568	kfree(f);
569	return err;
570}
571
572static void route4_walk(struct tcf_proto *tp, struct tcf_walker *arg,
573			bool rtnl_held)
574{
575	struct route4_head *head = rtnl_dereference(tp->root);
576	unsigned int h, h1;
577
578	if (head == NULL || arg->stop)
579		return;
580
581	for (h = 0; h <= 256; h++) {
582		struct route4_bucket *b = rtnl_dereference(head->table[h]);
583
584		if (b) {
585			for (h1 = 0; h1 <= 32; h1++) {
586				struct route4_filter *f;
587
588				for (f = rtnl_dereference(b->ht[h1]);
589				     f;
590				     f = rtnl_dereference(f->next)) {
591					if (!tc_cls_stats_dump(tp, arg, f))
592						return;
593				}
594			}
595		}
596	}
597}
598
599static int route4_dump(struct net *net, struct tcf_proto *tp, void *fh,
600		       struct sk_buff *skb, struct tcmsg *t, bool rtnl_held)
601{
602	struct route4_filter *f = fh;
603	struct nlattr *nest;
604	u32 id;
605
606	if (f == NULL)
607		return skb->len;
608
609	t->tcm_handle = f->handle;
610
611	nest = nla_nest_start_noflag(skb, TCA_OPTIONS);
612	if (nest == NULL)
613		goto nla_put_failure;
614
615	if (!(f->handle & 0x8000)) {
616		id = f->id & 0xFF;
617		if (nla_put_u32(skb, TCA_ROUTE4_TO, id))
618			goto nla_put_failure;
619	}
620	if (f->handle & 0x80000000) {
621		if ((f->handle >> 16) != 0xFFFF &&
622		    nla_put_u32(skb, TCA_ROUTE4_IIF, f->iif))
623			goto nla_put_failure;
624	} else {
625		id = f->id >> 16;
626		if (nla_put_u32(skb, TCA_ROUTE4_FROM, id))
627			goto nla_put_failure;
628	}
629	if (f->res.classid &&
630	    nla_put_u32(skb, TCA_ROUTE4_CLASSID, f->res.classid))
631		goto nla_put_failure;
632
633	if (tcf_exts_dump(skb, &f->exts) < 0)
634		goto nla_put_failure;
635
636	nla_nest_end(skb, nest);
637
638	if (tcf_exts_dump_stats(skb, &f->exts) < 0)
639		goto nla_put_failure;
640
641	return skb->len;
642
643nla_put_failure:
644	nla_nest_cancel(skb, nest);
645	return -1;
646}
647
648static void route4_bind_class(void *fh, u32 classid, unsigned long cl, void *q,
649			      unsigned long base)
650{
651	struct route4_filter *f = fh;
652
653	tc_cls_bind_class(classid, cl, q, &f->res, base);
654}
655
656static struct tcf_proto_ops cls_route4_ops __read_mostly = {
657	.kind		=	"route",
658	.classify	=	route4_classify,
659	.init		=	route4_init,
660	.destroy	=	route4_destroy,
661	.get		=	route4_get,
662	.change		=	route4_change,
663	.delete		=	route4_delete,
664	.walk		=	route4_walk,
665	.dump		=	route4_dump,
666	.bind_class	=	route4_bind_class,
667	.owner		=	THIS_MODULE,
668};
669
670static int __init init_route4(void)
671{
672	return register_tcf_proto_ops(&cls_route4_ops);
673}
674
675static void __exit exit_route4(void)
676{
677	unregister_tcf_proto_ops(&cls_route4_ops);
678}
679
680module_init(init_route4)
681module_exit(exit_route4)
682MODULE_LICENSE("GPL");
683