xref: /kernel/linux/linux-6.6/net/sched/em_meta.c (revision 62306a36) 
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * net/sched/em_meta.c	Metadata ematch
4 *
5 * Authors:	Thomas Graf <tgraf@suug.ch>
6 *
7 * ==========================================================================
8 *
9 * 	The metadata ematch compares two meta objects where each object
10 * 	represents either a meta value stored in the kernel or a static
11 * 	value provided by userspace. The objects are not provided by
12 * 	userspace itself but rather a definition providing the information
13 * 	to build them. Every object is of a certain type which must be
14 * 	equal to the object it is being compared to.
15 *
16 * 	The definition of a objects conists of the type (meta type), a
17 * 	identifier (meta id) and additional type specific information.
18 * 	The meta id is either TCF_META_TYPE_VALUE for values provided by
19 * 	userspace or a index to the meta operations table consisting of
20 * 	function pointers to type specific meta data collectors returning
21 * 	the value of the requested meta value.
22 *
23 * 	         lvalue                                   rvalue
24 * 	      +-----------+                           +-----------+
25 * 	      | type: INT |                           | type: INT |
26 * 	 def  | id: DEV   |                           | id: VALUE |
27 * 	      | data:     |                           | data: 3   |
28 * 	      +-----------+                           +-----------+
29 * 	            |                                       |
30 * 	            ---> meta_ops[INT][DEV](...)            |
31 *	                      |                             |
32 * 	            -----------                             |
33 * 	            V                                       V
34 * 	      +-----------+                           +-----------+
35 * 	      | type: INT |                           | type: INT |
36 * 	 obj  | id: DEV |                             | id: VALUE |
37 * 	      | data: 2   |<--data got filled out     | data: 3   |
38 * 	      +-----------+                           +-----------+
39 * 	            |                                         |
40 * 	            --------------> 2  equals 3 <--------------
41 *
42 * 	This is a simplified schema, the complexity varies depending
43 * 	on the meta type. Obviously, the length of the data must also
44 * 	be provided for non-numeric types.
45 *
46 * 	Additionally, type dependent modifiers such as shift operators
47 * 	or mask may be applied to extend the functionality. As of now,
48 * 	the variable length type supports shifting the byte string to
49 * 	the right, eating up any number of octets and thus supporting
50 * 	wildcard interface name comparisons such as "ppp%" matching
51 * 	ppp0..9.
52 *
53 * 	NOTE: Certain meta values depend on other subsystems and are
54 * 	      only available if that subsystem is enabled in the kernel.
55 */
56
57#include <linux/slab.h>
58#include <linux/module.h>
59#include <linux/types.h>
60#include <linux/kernel.h>
61#include <linux/sched.h>
62#include <linux/sched/loadavg.h>
63#include <linux/string.h>
64#include <linux/skbuff.h>
65#include <linux/random.h>
66#include <linux/if_vlan.h>
67#include <linux/tc_ematch/tc_em_meta.h>
68#include <net/dst.h>
69#include <net/route.h>
70#include <net/pkt_cls.h>
71#include <net/sock.h>
72
73struct meta_obj {
74	unsigned long		value;
75	unsigned int		len;
76};
77
78struct meta_value {
79	struct tcf_meta_val	hdr;
80	unsigned long		val;
81	unsigned int		len;
82};
83
84struct meta_match {
85	struct meta_value	lvalue;
86	struct meta_value	rvalue;
87};
88
89static inline int meta_id(struct meta_value *v)
90{
91	return TCF_META_ID(v->hdr.kind);
92}
93
94static inline int meta_type(struct meta_value *v)
95{
96	return TCF_META_TYPE(v->hdr.kind);
97}
98
99#define META_COLLECTOR(FUNC) static void meta_##FUNC(struct sk_buff *skb, \
100	struct tcf_pkt_info *info, struct meta_value *v, \
101	struct meta_obj *dst, int *err)
102
103/**************************************************************************
104 * System status & misc
105 **************************************************************************/
106
107META_COLLECTOR(int_random)
108{
109	get_random_bytes(&dst->value, sizeof(dst->value));
110}
111
112static inline unsigned long fixed_loadavg(int load)
113{
114	int rnd_load = load + (FIXED_1/200);
115	int rnd_frac = ((rnd_load & (FIXED_1-1)) * 100) >> FSHIFT;
116
117	return ((rnd_load >> FSHIFT) * 100) + rnd_frac;
118}
119
120META_COLLECTOR(int_loadavg_0)
121{
122	dst->value = fixed_loadavg(avenrun[0]);
123}
124
125META_COLLECTOR(int_loadavg_1)
126{
127	dst->value = fixed_loadavg(avenrun[1]);
128}
129
130META_COLLECTOR(int_loadavg_2)
131{
132	dst->value = fixed_loadavg(avenrun[2]);
133}
134
135/**************************************************************************
136 * Device names & indices
137 **************************************************************************/
138
139static inline int int_dev(struct net_device *dev, struct meta_obj *dst)
140{
141	if (unlikely(dev == NULL))
142		return -1;
143
144	dst->value = dev->ifindex;
145	return 0;
146}
147
148static inline int var_dev(struct net_device *dev, struct meta_obj *dst)
149{
150	if (unlikely(dev == NULL))
151		return -1;
152
153	dst->value = (unsigned long) dev->name;
154	dst->len = strlen(dev->name);
155	return 0;
156}
157
158META_COLLECTOR(int_dev)
159{
160	*err = int_dev(skb->dev, dst);
161}
162
163META_COLLECTOR(var_dev)
164{
165	*err = var_dev(skb->dev, dst);
166}
167
168/**************************************************************************
169 * vlan tag
170 **************************************************************************/
171
172META_COLLECTOR(int_vlan_tag)
173{
174	unsigned short tag;
175
176	if (skb_vlan_tag_present(skb))
177		dst->value = skb_vlan_tag_get(skb);
178	else if (!__vlan_get_tag(skb, &tag))
179		dst->value = tag;
180	else
181		*err = -1;
182}
183
184
185
186/**************************************************************************
187 * skb attributes
188 **************************************************************************/
189
190META_COLLECTOR(int_priority)
191{
192	dst->value = skb->priority;
193}
194
195META_COLLECTOR(int_protocol)
196{
197	/* Let userspace take care of the byte ordering */
198	dst->value = skb_protocol(skb, false);
199}
200
201META_COLLECTOR(int_pkttype)
202{
203	dst->value = skb->pkt_type;
204}
205
206META_COLLECTOR(int_pktlen)
207{
208	dst->value = skb->len;
209}
210
211META_COLLECTOR(int_datalen)
212{
213	dst->value = skb->data_len;
214}
215
216META_COLLECTOR(int_maclen)
217{
218	dst->value = skb->mac_len;
219}
220
221META_COLLECTOR(int_rxhash)
222{
223	dst->value = skb_get_hash(skb);
224}
225
226/**************************************************************************
227 * Netfilter
228 **************************************************************************/
229
230META_COLLECTOR(int_mark)
231{
232	dst->value = skb->mark;
233}
234
235/**************************************************************************
236 * Traffic Control
237 **************************************************************************/
238
239META_COLLECTOR(int_tcindex)
240{
241	dst->value = skb->tc_index;
242}
243
244/**************************************************************************
245 * Routing
246 **************************************************************************/
247
248META_COLLECTOR(int_rtclassid)
249{
250	if (unlikely(skb_dst(skb) == NULL))
251		*err = -1;
252	else
253#ifdef CONFIG_IP_ROUTE_CLASSID
254		dst->value = skb_dst(skb)->tclassid;
255#else
256		dst->value = 0;
257#endif
258}
259
260META_COLLECTOR(int_rtiif)
261{
262	if (unlikely(skb_rtable(skb) == NULL))
263		*err = -1;
264	else
265		dst->value = inet_iif(skb);
266}
267
268/**************************************************************************
269 * Socket Attributes
270 **************************************************************************/
271
272#define skip_nonlocal(skb) \
273	(unlikely(skb->sk == NULL))
274
275META_COLLECTOR(int_sk_family)
276{
277	if (skip_nonlocal(skb)) {
278		*err = -1;
279		return;
280	}
281	dst->value = skb->sk->sk_family;
282}
283
284META_COLLECTOR(int_sk_state)
285{
286	if (skip_nonlocal(skb)) {
287		*err = -1;
288		return;
289	}
290	dst->value = skb->sk->sk_state;
291}
292
293META_COLLECTOR(int_sk_reuse)
294{
295	if (skip_nonlocal(skb)) {
296		*err = -1;
297		return;
298	}
299	dst->value = skb->sk->sk_reuse;
300}
301
302META_COLLECTOR(int_sk_bound_if)
303{
304	if (skip_nonlocal(skb)) {
305		*err = -1;
306		return;
307	}
308	/* No error if bound_dev_if is 0, legal userspace check */
309	dst->value = skb->sk->sk_bound_dev_if;
310}
311
312META_COLLECTOR(var_sk_bound_if)
313{
314	int bound_dev_if;
315
316	if (skip_nonlocal(skb)) {
317		*err = -1;
318		return;
319	}
320
321	bound_dev_if = READ_ONCE(skb->sk->sk_bound_dev_if);
322	if (bound_dev_if == 0) {
323		dst->value = (unsigned long) "any";
324		dst->len = 3;
325	} else {
326		struct net_device *dev;
327
328		rcu_read_lock();
329		dev = dev_get_by_index_rcu(sock_net(skb->sk),
330					   bound_dev_if);
331		*err = var_dev(dev, dst);
332		rcu_read_unlock();
333	}
334}
335
336META_COLLECTOR(int_sk_refcnt)
337{
338	if (skip_nonlocal(skb)) {
339		*err = -1;
340		return;
341	}
342	dst->value = refcount_read(&skb->sk->sk_refcnt);
343}
344
345META_COLLECTOR(int_sk_rcvbuf)
346{
347	const struct sock *sk = skb_to_full_sk(skb);
348
349	if (!sk) {
350		*err = -1;
351		return;
352	}
353	dst->value = sk->sk_rcvbuf;
354}
355
356META_COLLECTOR(int_sk_shutdown)
357{
358	const struct sock *sk = skb_to_full_sk(skb);
359
360	if (!sk) {
361		*err = -1;
362		return;
363	}
364	dst->value = sk->sk_shutdown;
365}
366
367META_COLLECTOR(int_sk_proto)
368{
369	const struct sock *sk = skb_to_full_sk(skb);
370
371	if (!sk) {
372		*err = -1;
373		return;
374	}
375	dst->value = sk->sk_protocol;
376}
377
378META_COLLECTOR(int_sk_type)
379{
380	const struct sock *sk = skb_to_full_sk(skb);
381
382	if (!sk) {
383		*err = -1;
384		return;
385	}
386	dst->value = sk->sk_type;
387}
388
389META_COLLECTOR(int_sk_rmem_alloc)
390{
391	const struct sock *sk = skb_to_full_sk(skb);
392
393	if (!sk) {
394		*err = -1;
395		return;
396	}
397	dst->value = sk_rmem_alloc_get(sk);
398}
399
400META_COLLECTOR(int_sk_wmem_alloc)
401{
402	const struct sock *sk = skb_to_full_sk(skb);
403
404	if (!sk) {
405		*err = -1;
406		return;
407	}
408	dst->value = sk_wmem_alloc_get(sk);
409}
410
411META_COLLECTOR(int_sk_omem_alloc)
412{
413	const struct sock *sk = skb_to_full_sk(skb);
414
415	if (!sk) {
416		*err = -1;
417		return;
418	}
419	dst->value = atomic_read(&sk->sk_omem_alloc);
420}
421
422META_COLLECTOR(int_sk_rcv_qlen)
423{
424	const struct sock *sk = skb_to_full_sk(skb);
425
426	if (!sk) {
427		*err = -1;
428		return;
429	}
430	dst->value = sk->sk_receive_queue.qlen;
431}
432
433META_COLLECTOR(int_sk_snd_qlen)
434{
435	const struct sock *sk = skb_to_full_sk(skb);
436
437	if (!sk) {
438		*err = -1;
439		return;
440	}
441	dst->value = sk->sk_write_queue.qlen;
442}
443
444META_COLLECTOR(int_sk_wmem_queued)
445{
446	const struct sock *sk = skb_to_full_sk(skb);
447
448	if (!sk) {
449		*err = -1;
450		return;
451	}
452	dst->value = READ_ONCE(sk->sk_wmem_queued);
453}
454
455META_COLLECTOR(int_sk_fwd_alloc)
456{
457	const struct sock *sk = skb_to_full_sk(skb);
458
459	if (!sk) {
460		*err = -1;
461		return;
462	}
463	dst->value = sk_forward_alloc_get(sk);
464}
465
466META_COLLECTOR(int_sk_sndbuf)
467{
468	const struct sock *sk = skb_to_full_sk(skb);
469
470	if (!sk) {
471		*err = -1;
472		return;
473	}
474	dst->value = sk->sk_sndbuf;
475}
476
477META_COLLECTOR(int_sk_alloc)
478{
479	const struct sock *sk = skb_to_full_sk(skb);
480
481	if (!sk) {
482		*err = -1;
483		return;
484	}
485	dst->value = (__force int) sk->sk_allocation;
486}
487
488META_COLLECTOR(int_sk_hash)
489{
490	if (skip_nonlocal(skb)) {
491		*err = -1;
492		return;
493	}
494	dst->value = skb->sk->sk_hash;
495}
496
497META_COLLECTOR(int_sk_lingertime)
498{
499	const struct sock *sk = skb_to_full_sk(skb);
500
501	if (!sk) {
502		*err = -1;
503		return;
504	}
505	dst->value = READ_ONCE(sk->sk_lingertime) / HZ;
506}
507
508META_COLLECTOR(int_sk_err_qlen)
509{
510	const struct sock *sk = skb_to_full_sk(skb);
511
512	if (!sk) {
513		*err = -1;
514		return;
515	}
516	dst->value = sk->sk_error_queue.qlen;
517}
518
519META_COLLECTOR(int_sk_ack_bl)
520{
521	const struct sock *sk = skb_to_full_sk(skb);
522
523	if (!sk) {
524		*err = -1;
525		return;
526	}
527	dst->value = READ_ONCE(sk->sk_ack_backlog);
528}
529
530META_COLLECTOR(int_sk_max_ack_bl)
531{
532	const struct sock *sk = skb_to_full_sk(skb);
533
534	if (!sk) {
535		*err = -1;
536		return;
537	}
538	dst->value = READ_ONCE(sk->sk_max_ack_backlog);
539}
540
541META_COLLECTOR(int_sk_prio)
542{
543	const struct sock *sk = skb_to_full_sk(skb);
544
545	if (!sk) {
546		*err = -1;
547		return;
548	}
549	dst->value = sk->sk_priority;
550}
551
552META_COLLECTOR(int_sk_rcvlowat)
553{
554	const struct sock *sk = skb_to_full_sk(skb);
555
556	if (!sk) {
557		*err = -1;
558		return;
559	}
560	dst->value = READ_ONCE(sk->sk_rcvlowat);
561}
562
563META_COLLECTOR(int_sk_rcvtimeo)
564{
565	const struct sock *sk = skb_to_full_sk(skb);
566
567	if (!sk) {
568		*err = -1;
569		return;
570	}
571	dst->value = READ_ONCE(sk->sk_rcvtimeo) / HZ;
572}
573
574META_COLLECTOR(int_sk_sndtimeo)
575{
576	const struct sock *sk = skb_to_full_sk(skb);
577
578	if (!sk) {
579		*err = -1;
580		return;
581	}
582	dst->value = READ_ONCE(sk->sk_sndtimeo) / HZ;
583}
584
585META_COLLECTOR(int_sk_sendmsg_off)
586{
587	const struct sock *sk = skb_to_full_sk(skb);
588
589	if (!sk) {
590		*err = -1;
591		return;
592	}
593	dst->value = sk->sk_frag.offset;
594}
595
596META_COLLECTOR(int_sk_write_pend)
597{
598	const struct sock *sk = skb_to_full_sk(skb);
599
600	if (!sk) {
601		*err = -1;
602		return;
603	}
604	dst->value = sk->sk_write_pending;
605}
606
607/**************************************************************************
608 * Meta value collectors assignment table
609 **************************************************************************/
610
611struct meta_ops {
612	void		(*get)(struct sk_buff *, struct tcf_pkt_info *,
613			       struct meta_value *, struct meta_obj *, int *);
614};
615
616#define META_ID(name) TCF_META_ID_##name
617#define META_FUNC(name) { .get = meta_##name }
618
619/* Meta value operations table listing all meta value collectors and
620 * assigns them to a type and meta id. */
621static struct meta_ops __meta_ops[TCF_META_TYPE_MAX + 1][TCF_META_ID_MAX + 1] = {
622	[TCF_META_TYPE_VAR] = {
623		[META_ID(DEV)]			= META_FUNC(var_dev),
624		[META_ID(SK_BOUND_IF)] 		= META_FUNC(var_sk_bound_if),
625	},
626	[TCF_META_TYPE_INT] = {
627		[META_ID(RANDOM)]		= META_FUNC(int_random),
628		[META_ID(LOADAVG_0)]		= META_FUNC(int_loadavg_0),
629		[META_ID(LOADAVG_1)]		= META_FUNC(int_loadavg_1),
630		[META_ID(LOADAVG_2)]		= META_FUNC(int_loadavg_2),
631		[META_ID(DEV)]			= META_FUNC(int_dev),
632		[META_ID(PRIORITY)]		= META_FUNC(int_priority),
633		[META_ID(PROTOCOL)]		= META_FUNC(int_protocol),
634		[META_ID(PKTTYPE)]		= META_FUNC(int_pkttype),
635		[META_ID(PKTLEN)]		= META_FUNC(int_pktlen),
636		[META_ID(DATALEN)]		= META_FUNC(int_datalen),
637		[META_ID(MACLEN)]		= META_FUNC(int_maclen),
638		[META_ID(NFMARK)]		= META_FUNC(int_mark),
639		[META_ID(TCINDEX)]		= META_FUNC(int_tcindex),
640		[META_ID(RTCLASSID)]		= META_FUNC(int_rtclassid),
641		[META_ID(RTIIF)]		= META_FUNC(int_rtiif),
642		[META_ID(SK_FAMILY)]		= META_FUNC(int_sk_family),
643		[META_ID(SK_STATE)]		= META_FUNC(int_sk_state),
644		[META_ID(SK_REUSE)]		= META_FUNC(int_sk_reuse),
645		[META_ID(SK_BOUND_IF)]		= META_FUNC(int_sk_bound_if),
646		[META_ID(SK_REFCNT)]		= META_FUNC(int_sk_refcnt),
647		[META_ID(SK_RCVBUF)]		= META_FUNC(int_sk_rcvbuf),
648		[META_ID(SK_SNDBUF)]		= META_FUNC(int_sk_sndbuf),
649		[META_ID(SK_SHUTDOWN)]		= META_FUNC(int_sk_shutdown),
650		[META_ID(SK_PROTO)]		= META_FUNC(int_sk_proto),
651		[META_ID(SK_TYPE)]		= META_FUNC(int_sk_type),
652		[META_ID(SK_RMEM_ALLOC)]	= META_FUNC(int_sk_rmem_alloc),
653		[META_ID(SK_WMEM_ALLOC)]	= META_FUNC(int_sk_wmem_alloc),
654		[META_ID(SK_OMEM_ALLOC)]	= META_FUNC(int_sk_omem_alloc),
655		[META_ID(SK_WMEM_QUEUED)]	= META_FUNC(int_sk_wmem_queued),
656		[META_ID(SK_RCV_QLEN)]		= META_FUNC(int_sk_rcv_qlen),
657		[META_ID(SK_SND_QLEN)]		= META_FUNC(int_sk_snd_qlen),
658		[META_ID(SK_ERR_QLEN)]		= META_FUNC(int_sk_err_qlen),
659		[META_ID(SK_FORWARD_ALLOCS)]	= META_FUNC(int_sk_fwd_alloc),
660		[META_ID(SK_ALLOCS)]		= META_FUNC(int_sk_alloc),
661		[META_ID(SK_HASH)]		= META_FUNC(int_sk_hash),
662		[META_ID(SK_LINGERTIME)]	= META_FUNC(int_sk_lingertime),
663		[META_ID(SK_ACK_BACKLOG)]	= META_FUNC(int_sk_ack_bl),
664		[META_ID(SK_MAX_ACK_BACKLOG)]	= META_FUNC(int_sk_max_ack_bl),
665		[META_ID(SK_PRIO)]		= META_FUNC(int_sk_prio),
666		[META_ID(SK_RCVLOWAT)]		= META_FUNC(int_sk_rcvlowat),
667		[META_ID(SK_RCVTIMEO)]		= META_FUNC(int_sk_rcvtimeo),
668		[META_ID(SK_SNDTIMEO)]		= META_FUNC(int_sk_sndtimeo),
669		[META_ID(SK_SENDMSG_OFF)]	= META_FUNC(int_sk_sendmsg_off),
670		[META_ID(SK_WRITE_PENDING)]	= META_FUNC(int_sk_write_pend),
671		[META_ID(VLAN_TAG)]		= META_FUNC(int_vlan_tag),
672		[META_ID(RXHASH)]		= META_FUNC(int_rxhash),
673	}
674};
675
676static inline struct meta_ops *meta_ops(struct meta_value *val)
677{
678	return &__meta_ops[meta_type(val)][meta_id(val)];
679}
680
681/**************************************************************************
682 * Type specific operations for TCF_META_TYPE_VAR
683 **************************************************************************/
684
685static int meta_var_compare(struct meta_obj *a, struct meta_obj *b)
686{
687	int r = a->len - b->len;
688
689	if (r == 0)
690		r = memcmp((void *) a->value, (void *) b->value, a->len);
691
692	return r;
693}
694
695static int meta_var_change(struct meta_value *dst, struct nlattr *nla)
696{
697	int len = nla_len(nla);
698
699	dst->val = (unsigned long)kmemdup(nla_data(nla), len, GFP_KERNEL);
700	if (dst->val == 0UL)
701		return -ENOMEM;
702	dst->len = len;
703	return 0;
704}
705
706static void meta_var_destroy(struct meta_value *v)
707{
708	kfree((void *) v->val);
709}
710
711static void meta_var_apply_extras(struct meta_value *v,
712				  struct meta_obj *dst)
713{
714	int shift = v->hdr.shift;
715
716	if (shift && shift < dst->len)
717		dst->len -= shift;
718}
719
720static int meta_var_dump(struct sk_buff *skb, struct meta_value *v, int tlv)
721{
722	if (v->val && v->len &&
723	    nla_put(skb, tlv, v->len, (void *) v->val))
724		goto nla_put_failure;
725	return 0;
726
727nla_put_failure:
728	return -1;
729}
730
731/**************************************************************************
732 * Type specific operations for TCF_META_TYPE_INT
733 **************************************************************************/
734
735static int meta_int_compare(struct meta_obj *a, struct meta_obj *b)
736{
737	/* Let gcc optimize it, the unlikely is not really based on
738	 * some numbers but jump free code for mismatches seems
739	 * more logical. */
740	if (unlikely(a->value == b->value))
741		return 0;
742	else if (a->value < b->value)
743		return -1;
744	else
745		return 1;
746}
747
748static int meta_int_change(struct meta_value *dst, struct nlattr *nla)
749{
750	if (nla_len(nla) >= sizeof(unsigned long)) {
751		dst->val = *(unsigned long *) nla_data(nla);
752		dst->len = sizeof(unsigned long);
753	} else if (nla_len(nla) == sizeof(u32)) {
754		dst->val = nla_get_u32(nla);
755		dst->len = sizeof(u32);
756	} else
757		return -EINVAL;
758
759	return 0;
760}
761
762static void meta_int_apply_extras(struct meta_value *v,
763				  struct meta_obj *dst)
764{
765	if (v->hdr.shift)
766		dst->value >>= v->hdr.shift;
767
768	if (v->val)
769		dst->value &= v->val;
770}
771
772static int meta_int_dump(struct sk_buff *skb, struct meta_value *v, int tlv)
773{
774	if (v->len == sizeof(unsigned long)) {
775		if (nla_put(skb, tlv, sizeof(unsigned long), &v->val))
776			goto nla_put_failure;
777	} else if (v->len == sizeof(u32)) {
778		if (nla_put_u32(skb, tlv, v->val))
779			goto nla_put_failure;
780	}
781
782	return 0;
783
784nla_put_failure:
785	return -1;
786}
787
788/**************************************************************************
789 * Type specific operations table
790 **************************************************************************/
791
792struct meta_type_ops {
793	void	(*destroy)(struct meta_value *);
794	int	(*compare)(struct meta_obj *, struct meta_obj *);
795	int	(*change)(struct meta_value *, struct nlattr *);
796	void	(*apply_extras)(struct meta_value *, struct meta_obj *);
797	int	(*dump)(struct sk_buff *, struct meta_value *, int);
798};
799
800static const struct meta_type_ops __meta_type_ops[TCF_META_TYPE_MAX + 1] = {
801	[TCF_META_TYPE_VAR] = {
802		.destroy = meta_var_destroy,
803		.compare = meta_var_compare,
804		.change = meta_var_change,
805		.apply_extras = meta_var_apply_extras,
806		.dump = meta_var_dump
807	},
808	[TCF_META_TYPE_INT] = {
809		.compare = meta_int_compare,
810		.change = meta_int_change,
811		.apply_extras = meta_int_apply_extras,
812		.dump = meta_int_dump
813	}
814};
815
816static inline const struct meta_type_ops *meta_type_ops(struct meta_value *v)
817{
818	return &__meta_type_ops[meta_type(v)];
819}
820
821/**************************************************************************
822 * Core
823 **************************************************************************/
824
825static int meta_get(struct sk_buff *skb, struct tcf_pkt_info *info,
826		    struct meta_value *v, struct meta_obj *dst)
827{
828	int err = 0;
829
830	if (meta_id(v) == TCF_META_ID_VALUE) {
831		dst->value = v->val;
832		dst->len = v->len;
833		return 0;
834	}
835
836	meta_ops(v)->get(skb, info, v, dst, &err);
837	if (err < 0)
838		return err;
839
840	if (meta_type_ops(v)->apply_extras)
841		meta_type_ops(v)->apply_extras(v, dst);
842
843	return 0;
844}
845
846static int em_meta_match(struct sk_buff *skb, struct tcf_ematch *m,
847			 struct tcf_pkt_info *info)
848{
849	int r;
850	struct meta_match *meta = (struct meta_match *) m->data;
851	struct meta_obj l_value, r_value;
852
853	if (meta_get(skb, info, &meta->lvalue, &l_value) < 0 ||
854	    meta_get(skb, info, &meta->rvalue, &r_value) < 0)
855		return 0;
856
857	r = meta_type_ops(&meta->lvalue)->compare(&l_value, &r_value);
858
859	switch (meta->lvalue.hdr.op) {
860	case TCF_EM_OPND_EQ:
861		return !r;
862	case TCF_EM_OPND_LT:
863		return r < 0;
864	case TCF_EM_OPND_GT:
865		return r > 0;
866	}
867
868	return 0;
869}
870
871static void meta_delete(struct meta_match *meta)
872{
873	if (meta) {
874		const struct meta_type_ops *ops = meta_type_ops(&meta->lvalue);
875
876		if (ops && ops->destroy) {
877			ops->destroy(&meta->lvalue);
878			ops->destroy(&meta->rvalue);
879		}
880	}
881
882	kfree(meta);
883}
884
885static inline int meta_change_data(struct meta_value *dst, struct nlattr *nla)
886{
887	if (nla) {
888		if (nla_len(nla) == 0)
889			return -EINVAL;
890
891		return meta_type_ops(dst)->change(dst, nla);
892	}
893
894	return 0;
895}
896
897static inline int meta_is_supported(struct meta_value *val)
898{
899	return !meta_id(val) || meta_ops(val)->get;
900}
901
902static const struct nla_policy meta_policy[TCA_EM_META_MAX + 1] = {
903	[TCA_EM_META_HDR]	= { .len = sizeof(struct tcf_meta_hdr) },
904};
905
906static int em_meta_change(struct net *net, void *data, int len,
907			  struct tcf_ematch *m)
908{
909	int err;
910	struct nlattr *tb[TCA_EM_META_MAX + 1];
911	struct tcf_meta_hdr *hdr;
912	struct meta_match *meta = NULL;
913
914	err = nla_parse_deprecated(tb, TCA_EM_META_MAX, data, len,
915				   meta_policy, NULL);
916	if (err < 0)
917		goto errout;
918
919	err = -EINVAL;
920	if (tb[TCA_EM_META_HDR] == NULL)
921		goto errout;
922	hdr = nla_data(tb[TCA_EM_META_HDR]);
923
924	if (TCF_META_TYPE(hdr->left.kind) != TCF_META_TYPE(hdr->right.kind) ||
925	    TCF_META_TYPE(hdr->left.kind) > TCF_META_TYPE_MAX ||
926	    TCF_META_ID(hdr->left.kind) > TCF_META_ID_MAX ||
927	    TCF_META_ID(hdr->right.kind) > TCF_META_ID_MAX)
928		goto errout;
929
930	meta = kzalloc(sizeof(*meta), GFP_KERNEL);
931	if (meta == NULL) {
932		err = -ENOMEM;
933		goto errout;
934	}
935
936	memcpy(&meta->lvalue.hdr, &hdr->left, sizeof(hdr->left));
937	memcpy(&meta->rvalue.hdr, &hdr->right, sizeof(hdr->right));
938
939	if (!meta_is_supported(&meta->lvalue) ||
940	    !meta_is_supported(&meta->rvalue)) {
941		err = -EOPNOTSUPP;
942		goto errout;
943	}
944
945	if (meta_change_data(&meta->lvalue, tb[TCA_EM_META_LVALUE]) < 0 ||
946	    meta_change_data(&meta->rvalue, tb[TCA_EM_META_RVALUE]) < 0)
947		goto errout;
948
949	m->datalen = sizeof(*meta);
950	m->data = (unsigned long) meta;
951
952	err = 0;
953errout:
954	if (err && meta)
955		meta_delete(meta);
956	return err;
957}
958
959static void em_meta_destroy(struct tcf_ematch *m)
960{
961	if (m)
962		meta_delete((struct meta_match *) m->data);
963}
964
965static int em_meta_dump(struct sk_buff *skb, struct tcf_ematch *em)
966{
967	struct meta_match *meta = (struct meta_match *) em->data;
968	struct tcf_meta_hdr hdr;
969	const struct meta_type_ops *ops;
970
971	memset(&hdr, 0, sizeof(hdr));
972	memcpy(&hdr.left, &meta->lvalue.hdr, sizeof(hdr.left));
973	memcpy(&hdr.right, &meta->rvalue.hdr, sizeof(hdr.right));
974
975	if (nla_put(skb, TCA_EM_META_HDR, sizeof(hdr), &hdr))
976		goto nla_put_failure;
977
978	ops = meta_type_ops(&meta->lvalue);
979	if (ops->dump(skb, &meta->lvalue, TCA_EM_META_LVALUE) < 0 ||
980	    ops->dump(skb, &meta->rvalue, TCA_EM_META_RVALUE) < 0)
981		goto nla_put_failure;
982
983	return 0;
984
985nla_put_failure:
986	return -1;
987}
988
989static struct tcf_ematch_ops em_meta_ops = {
990	.kind	  = TCF_EM_META,
991	.change	  = em_meta_change,
992	.match	  = em_meta_match,
993	.destroy  = em_meta_destroy,
994	.dump	  = em_meta_dump,
995	.owner	  = THIS_MODULE,
996	.link	  = LIST_HEAD_INIT(em_meta_ops.link)
997};
998
999static int __init init_em_meta(void)
1000{
1001	return tcf_em_register(&em_meta_ops);
1002}
1003
1004static void __exit exit_em_meta(void)
1005{
1006	tcf_em_unregister(&em_meta_ops);
1007}
1008
1009MODULE_LICENSE("GPL");
1010
1011module_init(init_em_meta);
1012module_exit(exit_em_meta);
1013
1014MODULE_ALIAS_TCF_EMATCH(TCF_EM_META);
1015