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 * 	Additionaly, type dependant 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{
78	unsigned long		value;
79	unsigned int		len;
80};
81
82struct meta_value
83{
84	struct tcf_meta_val	hdr;
85	unsigned long		val;
86	unsigned int		len;
87};
88
89struct meta_match
90{
91	struct meta_value	lvalue;
92	struct meta_value	rvalue;
93};
94
95static inline int meta_id(struct meta_value *v)
96{
97	return TCF_META_ID(v->hdr.kind);
98}
99
100static inline int meta_type(struct meta_value *v)
101{
102	return TCF_META_TYPE(v->hdr.kind);
103}
104
105#define META_COLLECTOR(FUNC) static void meta_##FUNC(struct sk_buff *skb, \
106	struct tcf_pkt_info *info, struct meta_value *v, \
107	struct meta_obj *dst, int *err)
108
109/**************************************************************************
110 * System status & misc
111 **************************************************************************/
112
113META_COLLECTOR(int_random)
114{
115	get_random_bytes(&dst->value, sizeof(dst->value));
116}
117
118static inline unsigned long fixed_loadavg(int load)
119{
120	int rnd_load = load + (FIXED_1/200);
121	int rnd_frac = ((rnd_load & (FIXED_1-1)) * 100) >> FSHIFT;
122
123	return ((rnd_load >> FSHIFT) * 100) + rnd_frac;
124}
125
126META_COLLECTOR(int_loadavg_0)
127{
128	dst->value = fixed_loadavg(avenrun[0]);
129}
130
131META_COLLECTOR(int_loadavg_1)
132{
133	dst->value = fixed_loadavg(avenrun[1]);
134}
135
136META_COLLECTOR(int_loadavg_2)
137{
138	dst->value = fixed_loadavg(avenrun[2]);
139}
140
141/**************************************************************************
142 * Device names & indices
143 **************************************************************************/
144
145static inline int int_dev(struct net_device *dev, struct meta_obj *dst)
146{
147	if (unlikely(dev == NULL))
148		return -1;
149
150	dst->value = dev->ifindex;
151	return 0;
152}
153
154static inline int var_dev(struct net_device *dev, struct meta_obj *dst)
155{
156	if (unlikely(dev == NULL))
157		return -1;
158
159	dst->value = (unsigned long) dev->name;
160	dst->len = strlen(dev->name);
161	return 0;
162}
163
164META_COLLECTOR(int_dev)
165{
166	*err = int_dev(skb->dev, dst);
167}
168
169META_COLLECTOR(var_dev)
170{
171	*err = var_dev(skb->dev, dst);
172}
173
174/**************************************************************************
175 * vlan tag
176 **************************************************************************/
177
178META_COLLECTOR(int_vlan_tag)
179{
180	unsigned short tag;
181
182	tag = vlan_tx_tag_get(skb);
183	if (!tag && __vlan_get_tag(skb, &tag))
184		*err = -1;
185	else
186		dst->value = tag;
187}
188
189
190
191/**************************************************************************
192 * skb attributes
193 **************************************************************************/
194
195META_COLLECTOR(int_priority)
196{
197	dst->value = skb->priority;
198}
199
200META_COLLECTOR(int_protocol)
201{
202	/* Let userspace take care of the byte ordering */
203	dst->value = skb->protocol;
204}
205
206META_COLLECTOR(int_pkttype)
207{
208	dst->value = skb->pkt_type;
209}
210
211META_COLLECTOR(int_pktlen)
212{
213	dst->value = skb->len;
214}
215
216META_COLLECTOR(int_datalen)
217{
218	dst->value = skb->data_len;
219}
220
221META_COLLECTOR(int_maclen)
222{
223	dst->value = skb->mac_len;
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_NET_CLS_ROUTE
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 = skb_rtable(skb)->fl.iif;
266}
267
268/**************************************************************************
269 * Socket Attributes
270 **************************************************************************/
271
272#define SKIP_NONLOCAL(skb)			\
273	if (unlikely(skb->sk == NULL)) {	\
274		*err = -1;			\
275		return;				\
276	}
277
278META_COLLECTOR(int_sk_family)
279{
280	SKIP_NONLOCAL(skb);
281	dst->value = skb->sk->sk_family;
282}
283
284META_COLLECTOR(int_sk_state)
285{
286	SKIP_NONLOCAL(skb);
287	dst->value = skb->sk->sk_state;
288}
289
290META_COLLECTOR(int_sk_reuse)
291{
292	SKIP_NONLOCAL(skb);
293	dst->value = skb->sk->sk_reuse;
294}
295
296META_COLLECTOR(int_sk_bound_if)
297{
298	SKIP_NONLOCAL(skb);
299	/* No error if bound_dev_if is 0, legal userspace check */
300	dst->value = skb->sk->sk_bound_dev_if;
301}
302
303META_COLLECTOR(var_sk_bound_if)
304{
305	SKIP_NONLOCAL(skb);
306
307	if (skb->sk->sk_bound_dev_if == 0) {
308		dst->value = (unsigned long) "any";
309		dst->len = 3;
310	} else {
311		struct net_device *dev;
312
313		rcu_read_lock();
314		dev = dev_get_by_index_rcu(sock_net(skb->sk),
315					   skb->sk->sk_bound_dev_if);
316		*err = var_dev(dev, dst);
317		rcu_read_unlock();
318	}
319}
320
321META_COLLECTOR(int_sk_refcnt)
322{
323	SKIP_NONLOCAL(skb);
324	dst->value = atomic_read(&skb->sk->sk_refcnt);
325}
326
327META_COLLECTOR(int_sk_rcvbuf)
328{
329	SKIP_NONLOCAL(skb);
330	dst->value = skb->sk->sk_rcvbuf;
331}
332
333META_COLLECTOR(int_sk_shutdown)
334{
335	SKIP_NONLOCAL(skb);
336	dst->value = skb->sk->sk_shutdown;
337}
338
339META_COLLECTOR(int_sk_proto)
340{
341	SKIP_NONLOCAL(skb);
342	dst->value = skb->sk->sk_protocol;
343}
344
345META_COLLECTOR(int_sk_type)
346{
347	SKIP_NONLOCAL(skb);
348	dst->value = skb->sk->sk_type;
349}
350
351META_COLLECTOR(int_sk_rmem_alloc)
352{
353	SKIP_NONLOCAL(skb);
354	dst->value = sk_rmem_alloc_get(skb->sk);
355}
356
357META_COLLECTOR(int_sk_wmem_alloc)
358{
359	SKIP_NONLOCAL(skb);
360	dst->value = sk_wmem_alloc_get(skb->sk);
361}
362
363META_COLLECTOR(int_sk_omem_alloc)
364{
365	SKIP_NONLOCAL(skb);
366	dst->value = atomic_read(&skb->sk->sk_omem_alloc);
367}
368
369META_COLLECTOR(int_sk_rcv_qlen)
370{
371	SKIP_NONLOCAL(skb);
372	dst->value = skb->sk->sk_receive_queue.qlen;
373}
374
375META_COLLECTOR(int_sk_snd_qlen)
376{
377	SKIP_NONLOCAL(skb);
378	dst->value = skb->sk->sk_write_queue.qlen;
379}
380
381META_COLLECTOR(int_sk_wmem_queued)
382{
383	SKIP_NONLOCAL(skb);
384	dst->value = skb->sk->sk_wmem_queued;
385}
386
387META_COLLECTOR(int_sk_fwd_alloc)
388{
389	SKIP_NONLOCAL(skb);
390	dst->value = skb->sk->sk_forward_alloc;
391}
392
393META_COLLECTOR(int_sk_sndbuf)
394{
395	SKIP_NONLOCAL(skb);
396	dst->value = skb->sk->sk_sndbuf;
397}
398
399META_COLLECTOR(int_sk_alloc)
400{
401	SKIP_NONLOCAL(skb);
402	dst->value = skb->sk->sk_allocation;
403}
404
405META_COLLECTOR(int_sk_route_caps)
406{
407	SKIP_NONLOCAL(skb);
408	dst->value = skb->sk->sk_route_caps;
409}
410
411META_COLLECTOR(int_sk_hash)
412{
413	SKIP_NONLOCAL(skb);
414	dst->value = skb->sk->sk_hash;
415}
416
417META_COLLECTOR(int_sk_lingertime)
418{
419	SKIP_NONLOCAL(skb);
420	dst->value = skb->sk->sk_lingertime / HZ;
421}
422
423META_COLLECTOR(int_sk_err_qlen)
424{
425	SKIP_NONLOCAL(skb);
426	dst->value = skb->sk->sk_error_queue.qlen;
427}
428
429META_COLLECTOR(int_sk_ack_bl)
430{
431	SKIP_NONLOCAL(skb);
432	dst->value = skb->sk->sk_ack_backlog;
433}
434
435META_COLLECTOR(int_sk_max_ack_bl)
436{
437	SKIP_NONLOCAL(skb);
438	dst->value = skb->sk->sk_max_ack_backlog;
439}
440
441META_COLLECTOR(int_sk_prio)
442{
443	SKIP_NONLOCAL(skb);
444	dst->value = skb->sk->sk_priority;
445}
446
447META_COLLECTOR(int_sk_rcvlowat)
448{
449	SKIP_NONLOCAL(skb);
450	dst->value = skb->sk->sk_rcvlowat;
451}
452
453META_COLLECTOR(int_sk_rcvtimeo)
454{
455	SKIP_NONLOCAL(skb);
456	dst->value = skb->sk->sk_rcvtimeo / HZ;
457}
458
459META_COLLECTOR(int_sk_sndtimeo)
460{
461	SKIP_NONLOCAL(skb);
462	dst->value = skb->sk->sk_sndtimeo / HZ;
463}
464
465META_COLLECTOR(int_sk_sendmsg_off)
466{
467	SKIP_NONLOCAL(skb);
468	dst->value = skb->sk->sk_sndmsg_off;
469}
470
471META_COLLECTOR(int_sk_write_pend)
472{
473	SKIP_NONLOCAL(skb);
474	dst->value = skb->sk->sk_write_pending;
475}
476
477/**************************************************************************
478 * Meta value collectors assignment table
479 **************************************************************************/
480
481struct meta_ops
482{
483	void		(*get)(struct sk_buff *, struct tcf_pkt_info *,
484			       struct meta_value *, struct meta_obj *, int *);
485};
486
487#define META_ID(name) TCF_META_ID_##name
488#define META_FUNC(name) { .get = meta_##name }
489
490/* Meta value operations table listing all meta value collectors and
491 * assigns them to a type and meta id. */
492static struct meta_ops __meta_ops[TCF_META_TYPE_MAX+1][TCF_META_ID_MAX+1] = {
493	[TCF_META_TYPE_VAR] = {
494		[META_ID(DEV)]			= META_FUNC(var_dev),
495		[META_ID(SK_BOUND_IF)] 		= META_FUNC(var_sk_bound_if),
496	},
497	[TCF_META_TYPE_INT] = {
498		[META_ID(RANDOM)]		= META_FUNC(int_random),
499		[META_ID(LOADAVG_0)]		= META_FUNC(int_loadavg_0),
500		[META_ID(LOADAVG_1)]		= META_FUNC(int_loadavg_1),
501		[META_ID(LOADAVG_2)]		= META_FUNC(int_loadavg_2),
502		[META_ID(DEV)]			= META_FUNC(int_dev),
503		[META_ID(PRIORITY)]		= META_FUNC(int_priority),
504		[META_ID(PROTOCOL)]		= META_FUNC(int_protocol),
505		[META_ID(PKTTYPE)]		= META_FUNC(int_pkttype),
506		[META_ID(PKTLEN)]		= META_FUNC(int_pktlen),
507		[META_ID(DATALEN)]		= META_FUNC(int_datalen),
508		[META_ID(MACLEN)]		= META_FUNC(int_maclen),
509		[META_ID(NFMARK)]		= META_FUNC(int_mark),
510		[META_ID(TCINDEX)]		= META_FUNC(int_tcindex),
511		[META_ID(RTCLASSID)]		= META_FUNC(int_rtclassid),
512		[META_ID(RTIIF)]		= META_FUNC(int_rtiif),
513		[META_ID(SK_FAMILY)]		= META_FUNC(int_sk_family),
514		[META_ID(SK_STATE)]		= META_FUNC(int_sk_state),
515		[META_ID(SK_REUSE)]		= META_FUNC(int_sk_reuse),
516		[META_ID(SK_BOUND_IF)]		= META_FUNC(int_sk_bound_if),
517		[META_ID(SK_REFCNT)]		= META_FUNC(int_sk_refcnt),
518		[META_ID(SK_RCVBUF)]		= META_FUNC(int_sk_rcvbuf),
519		[META_ID(SK_SNDBUF)]		= META_FUNC(int_sk_sndbuf),
520		[META_ID(SK_SHUTDOWN)]		= META_FUNC(int_sk_shutdown),
521		[META_ID(SK_PROTO)]		= META_FUNC(int_sk_proto),
522		[META_ID(SK_TYPE)]		= META_FUNC(int_sk_type),
523		[META_ID(SK_RMEM_ALLOC)]	= META_FUNC(int_sk_rmem_alloc),
524		[META_ID(SK_WMEM_ALLOC)]	= META_FUNC(int_sk_wmem_alloc),
525		[META_ID(SK_OMEM_ALLOC)]	= META_FUNC(int_sk_omem_alloc),
526		[META_ID(SK_WMEM_QUEUED)]	= META_FUNC(int_sk_wmem_queued),
527		[META_ID(SK_RCV_QLEN)]		= META_FUNC(int_sk_rcv_qlen),
528		[META_ID(SK_SND_QLEN)]		= META_FUNC(int_sk_snd_qlen),
529		[META_ID(SK_ERR_QLEN)]		= META_FUNC(int_sk_err_qlen),
530		[META_ID(SK_FORWARD_ALLOCS)]	= META_FUNC(int_sk_fwd_alloc),
531		[META_ID(SK_ALLOCS)]		= META_FUNC(int_sk_alloc),
532		[META_ID(SK_ROUTE_CAPS)]	= META_FUNC(int_sk_route_caps),
533		[META_ID(SK_HASH)]		= META_FUNC(int_sk_hash),
534		[META_ID(SK_LINGERTIME)]	= META_FUNC(int_sk_lingertime),
535		[META_ID(SK_ACK_BACKLOG)]	= META_FUNC(int_sk_ack_bl),
536		[META_ID(SK_MAX_ACK_BACKLOG)]	= META_FUNC(int_sk_max_ack_bl),
537		[META_ID(SK_PRIO)]		= META_FUNC(int_sk_prio),
538		[META_ID(SK_RCVLOWAT)]		= META_FUNC(int_sk_rcvlowat),
539		[META_ID(SK_RCVTIMEO)]		= META_FUNC(int_sk_rcvtimeo),
540		[META_ID(SK_SNDTIMEO)]		= META_FUNC(int_sk_sndtimeo),
541		[META_ID(SK_SENDMSG_OFF)]	= META_FUNC(int_sk_sendmsg_off),
542		[META_ID(SK_WRITE_PENDING)]	= META_FUNC(int_sk_write_pend),
543		[META_ID(VLAN_TAG)]		= META_FUNC(int_vlan_tag),
544	}
545};
546
547static inline struct meta_ops * meta_ops(struct meta_value *val)
548{
549	return &__meta_ops[meta_type(val)][meta_id(val)];
550}
551
552/**************************************************************************
553 * Type specific operations for TCF_META_TYPE_VAR
554 **************************************************************************/
555
556static int meta_var_compare(struct meta_obj *a, struct meta_obj *b)
557{
558	int r = a->len - b->len;
559
560	if (r == 0)
561		r = memcmp((void *) a->value, (void *) b->value, a->len);
562
563	return r;
564}
565
566static int meta_var_change(struct meta_value *dst, struct nlattr *nla)
567{
568	int len = nla_len(nla);
569
570	dst->val = (unsigned long)kmemdup(nla_data(nla), len, GFP_KERNEL);
571	if (dst->val == 0UL)
572		return -ENOMEM;
573	dst->len = len;
574	return 0;
575}
576
577static void meta_var_destroy(struct meta_value *v)
578{
579	kfree((void *) v->val);
580}
581
582static void meta_var_apply_extras(struct meta_value *v,
583				  struct meta_obj *dst)
584{
585	int shift = v->hdr.shift;
586
587	if (shift && shift < dst->len)
588		dst->len -= shift;
589}
590
591static int meta_var_dump(struct sk_buff *skb, struct meta_value *v, int tlv)
592{
593	if (v->val && v->len)
594		NLA_PUT(skb, tlv, v->len, (void *) v->val);
595	return 0;
596
597nla_put_failure:
598	return -1;
599}
600
601/**************************************************************************
602 * Type specific operations for TCF_META_TYPE_INT
603 **************************************************************************/
604
605static int meta_int_compare(struct meta_obj *a, struct meta_obj *b)
606{
607	/* Let gcc optimize it, the unlikely is not really based on
608	 * some numbers but jump free code for mismatches seems
609	 * more logical. */
610	if (unlikely(a->value == b->value))
611		return 0;
612	else if (a->value < b->value)
613		return -1;
614	else
615		return 1;
616}
617
618static int meta_int_change(struct meta_value *dst, struct nlattr *nla)
619{
620	if (nla_len(nla) >= sizeof(unsigned long)) {
621		dst->val = *(unsigned long *) nla_data(nla);
622		dst->len = sizeof(unsigned long);
623	} else if (nla_len(nla) == sizeof(u32)) {
624		dst->val = nla_get_u32(nla);
625		dst->len = sizeof(u32);
626	} else
627		return -EINVAL;
628
629	return 0;
630}
631
632static void meta_int_apply_extras(struct meta_value *v,
633				  struct meta_obj *dst)
634{
635	if (v->hdr.shift)
636		dst->value >>= v->hdr.shift;
637
638	if (v->val)
639		dst->value &= v->val;
640}
641
642static int meta_int_dump(struct sk_buff *skb, struct meta_value *v, int tlv)
643{
644	if (v->len == sizeof(unsigned long))
645		NLA_PUT(skb, tlv, sizeof(unsigned long), &v->val);
646	else if (v->len == sizeof(u32)) {
647		NLA_PUT_U32(skb, tlv, v->val);
648	}
649
650	return 0;
651
652nla_put_failure:
653	return -1;
654}
655
656/**************************************************************************
657 * Type specific operations table
658 **************************************************************************/
659
660struct meta_type_ops
661{
662	void	(*destroy)(struct meta_value *);
663	int	(*compare)(struct meta_obj *, struct meta_obj *);
664	int	(*change)(struct meta_value *, struct nlattr *);
665	void	(*apply_extras)(struct meta_value *, struct meta_obj *);
666	int	(*dump)(struct sk_buff *, struct meta_value *, int);
667};
668
669static struct meta_type_ops __meta_type_ops[TCF_META_TYPE_MAX+1] = {
670	[TCF_META_TYPE_VAR] = {
671		.destroy = meta_var_destroy,
672		.compare = meta_var_compare,
673		.change = meta_var_change,
674		.apply_extras = meta_var_apply_extras,
675		.dump = meta_var_dump
676	},
677	[TCF_META_TYPE_INT] = {
678		.compare = meta_int_compare,
679		.change = meta_int_change,
680		.apply_extras = meta_int_apply_extras,
681		.dump = meta_int_dump
682	}
683};
684
685static inline struct meta_type_ops * meta_type_ops(struct meta_value *v)
686{
687	return &__meta_type_ops[meta_type(v)];
688}
689
690/**************************************************************************
691 * Core
692 **************************************************************************/
693
694static int meta_get(struct sk_buff *skb, struct tcf_pkt_info *info,
695		    struct meta_value *v, struct meta_obj *dst)
696{
697	int err = 0;
698
699	if (meta_id(v) == TCF_META_ID_VALUE) {
700		dst->value = v->val;
701		dst->len = v->len;
702		return 0;
703	}
704
705	meta_ops(v)->get(skb, info, v, dst, &err);
706	if (err < 0)
707		return err;
708
709	if (meta_type_ops(v)->apply_extras)
710	    meta_type_ops(v)->apply_extras(v, dst);
711
712	return 0;
713}
714
715static int em_meta_match(struct sk_buff *skb, struct tcf_ematch *m,
716			 struct tcf_pkt_info *info)
717{
718	int r;
719	struct meta_match *meta = (struct meta_match *) m->data;
720	struct meta_obj l_value, r_value;
721
722	if (meta_get(skb, info, &meta->lvalue, &l_value) < 0 ||
723	    meta_get(skb, info, &meta->rvalue, &r_value) < 0)
724		return 0;
725
726	r = meta_type_ops(&meta->lvalue)->compare(&l_value, &r_value);
727
728	switch (meta->lvalue.hdr.op) {
729		case TCF_EM_OPND_EQ:
730			return !r;
731		case TCF_EM_OPND_LT:
732			return r < 0;
733		case TCF_EM_OPND_GT:
734			return r > 0;
735	}
736
737	return 0;
738}
739
740static void meta_delete(struct meta_match *meta)
741{
742	if (meta) {
743		struct meta_type_ops *ops = meta_type_ops(&meta->lvalue);
744
745		if (ops && ops->destroy) {
746			ops->destroy(&meta->lvalue);
747			ops->destroy(&meta->rvalue);
748		}
749	}
750
751	kfree(meta);
752}
753
754static inline int meta_change_data(struct meta_value *dst, struct nlattr *nla)
755{
756	if (nla) {
757		if (nla_len(nla) == 0)
758			return -EINVAL;
759
760		return meta_type_ops(dst)->change(dst, nla);
761	}
762
763	return 0;
764}
765
766static inline int meta_is_supported(struct meta_value *val)
767{
768	return (!meta_id(val) || meta_ops(val)->get);
769}
770
771static const struct nla_policy meta_policy[TCA_EM_META_MAX + 1] = {
772	[TCA_EM_META_HDR]	= { .len = sizeof(struct tcf_meta_hdr) },
773};
774
775static int em_meta_change(struct tcf_proto *tp, void *data, int len,
776			  struct tcf_ematch *m)
777{
778	int err;
779	struct nlattr *tb[TCA_EM_META_MAX + 1];
780	struct tcf_meta_hdr *hdr;
781	struct meta_match *meta = NULL;
782
783	err = nla_parse(tb, TCA_EM_META_MAX, data, len, meta_policy);
784	if (err < 0)
785		goto errout;
786
787	err = -EINVAL;
788	if (tb[TCA_EM_META_HDR] == NULL)
789		goto errout;
790	hdr = nla_data(tb[TCA_EM_META_HDR]);
791
792	if (TCF_META_TYPE(hdr->left.kind) != TCF_META_TYPE(hdr->right.kind) ||
793	    TCF_META_TYPE(hdr->left.kind) > TCF_META_TYPE_MAX ||
794	    TCF_META_ID(hdr->left.kind) > TCF_META_ID_MAX ||
795	    TCF_META_ID(hdr->right.kind) > TCF_META_ID_MAX)
796		goto errout;
797
798	meta = kzalloc(sizeof(*meta), GFP_KERNEL);
799	if (meta == NULL)
800		goto errout;
801
802	memcpy(&meta->lvalue.hdr, &hdr->left, sizeof(hdr->left));
803	memcpy(&meta->rvalue.hdr, &hdr->right, sizeof(hdr->right));
804
805	if (!meta_is_supported(&meta->lvalue) ||
806	    !meta_is_supported(&meta->rvalue)) {
807		err = -EOPNOTSUPP;
808		goto errout;
809	}
810
811	if (meta_change_data(&meta->lvalue, tb[TCA_EM_META_LVALUE]) < 0 ||
812	    meta_change_data(&meta->rvalue, tb[TCA_EM_META_RVALUE]) < 0)
813		goto errout;
814
815	m->datalen = sizeof(*meta);
816	m->data = (unsigned long) meta;
817
818	err = 0;
819errout:
820	if (err && meta)
821		meta_delete(meta);
822	return err;
823}
824
825static void em_meta_destroy(struct tcf_proto *tp, struct tcf_ematch *m)
826{
827	if (m)
828		meta_delete((struct meta_match *) m->data);
829}
830
831static int em_meta_dump(struct sk_buff *skb, struct tcf_ematch *em)
832{
833	struct meta_match *meta = (struct meta_match *) em->data;
834	struct tcf_meta_hdr hdr;
835	struct meta_type_ops *ops;
836
837	memset(&hdr, 0, sizeof(hdr));
838	memcpy(&hdr.left, &meta->lvalue.hdr, sizeof(hdr.left));
839	memcpy(&hdr.right, &meta->rvalue.hdr, sizeof(hdr.right));
840
841	NLA_PUT(skb, TCA_EM_META_HDR, sizeof(hdr), &hdr);
842
843	ops = meta_type_ops(&meta->lvalue);
844	if (ops->dump(skb, &meta->lvalue, TCA_EM_META_LVALUE) < 0 ||
845	    ops->dump(skb, &meta->rvalue, TCA_EM_META_RVALUE) < 0)
846		goto nla_put_failure;
847
848	return 0;
849
850nla_put_failure:
851	return -1;
852}
853
854static struct tcf_ematch_ops em_meta_ops = {
855	.kind	  = TCF_EM_META,
856	.change	  = em_meta_change,
857	.match	  = em_meta_match,
858	.destroy  = em_meta_destroy,
859	.dump	  = em_meta_dump,
860	.owner	  = THIS_MODULE,
861	.link	  = LIST_HEAD_INIT(em_meta_ops.link)
862};
863
864static int __init init_em_meta(void)
865{
866	return tcf_em_register(&em_meta_ops);
867}
868
869static void __exit exit_em_meta(void)
870{
871	tcf_em_unregister(&em_meta_ops);
872}
873
874MODULE_LICENSE("GPL");
875
876module_init(init_em_meta);
877module_exit(exit_em_meta);
878
879MODULE_ALIAS_TCF_EMATCH(TCF_EM_META);
880