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