summaryrefslogtreecommitdiffstats
path: root/net/sched/em_meta.c
blob: cf68a59fdc5a4d4d6ac2bfbd5b63f99cd4574cee (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
/*
 * net/sched/em_meta.c	Metadata ematch
 *
 *		This program is free software; you can redistribute it and/or
 *		modify it under the terms of the GNU General Public License
 *		as published by the Free Software Foundation; either version
 *		2 of the License, or (at your option) any later version.
 *
 * Authors:	Thomas Graf <tgraf@suug.ch>
 *
 * ==========================================================================
 * 
 * 	The metadata ematch compares two meta objects where each object
 * 	represents either a meta value stored in the kernel or a static
 * 	value provided by userspace. The objects are not provided by
 * 	userspace itself but rather a definition providing the information
 * 	to build them. Every object is of a certain type which must be
 * 	equal to the object it is being compared to.
 *
 * 	The definition of a objects conists of the type (meta type), a
 * 	identifier (meta id) and additional type specific information.
 * 	The meta id is either TCF_META_TYPE_VALUE for values provided by
 * 	userspace or a index to the meta operations table consisting of
 * 	function pointers to type specific meta data collectors returning
 * 	the value of the requested meta value.
 *
 * 	         lvalue                                   rvalue
 * 	      +-----------+                           +-----------+
 * 	      | type: INT |                           | type: INT |
 * 	 def  | id: DEV   |                           | id: VALUE |
 * 	      | data:     |                           | data: 3   |
 * 	      +-----------+                           +-----------+
 * 	            |                                       |
 * 	            ---> meta_ops[INT][DEV](...)            |
 *	                      |                             |
 * 	            -----------                             |
 * 	            V                                       V
 * 	      +-----------+                           +-----------+
 * 	      | type: INT |                           | type: INT |
 * 	 obj  | id: DEV |                             | id: VALUE |
 * 	      | data: 2   |<--data got filled out     | data: 3   |
 * 	      +-----------+                           +-----------+
 * 	            |                                         |
 * 	            --------------> 2  equals 3 <--------------
 *
 * 	This is a simplified schema, the complexity varies depending
 * 	on the meta type. Obviously, the length of the data must also
 * 	be provided for non-numeric types.
 *
 * 	Additionaly, type dependant modifiers such as shift operators
 * 	or mask may be applied to extend the functionaliy. As of now,
 * 	the variable length type supports shifting the byte string to
 * 	the right, eating up any number of octets and thus supporting
 * 	wildcard interface name comparisons such as "ppp%" matching
 * 	ppp0..9.
 *
 * 	NOTE: Certain meta values depend on other subsystems and are
 * 	      only available if that subsytem is enabled in the kernel.
 */

#include <linux/config.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/string.h>
#include <linux/skbuff.h>
#include <linux/random.h>
#include <linux/tc_ematch/tc_em_meta.h>
#include <net/dst.h>
#include <net/route.h>
#include <net/pkt_cls.h>
#include <net/sock.h>

struct meta_obj
{
	unsigned long		value;
	unsigned int		len;
};

struct meta_value
{
	struct tcf_meta_val	hdr;
	unsigned long		val;
	unsigned int		len;
};

struct meta_match
{
	struct meta_value	lvalue;
	struct meta_value	rvalue;
};

static inline int meta_id(struct meta_value *v)
{
	return TCF_META_ID(v->hdr.kind);
}

static inline int meta_type(struct meta_value *v)
{
	return TCF_META_TYPE(v->hdr.kind);
}

#define META_COLLECTOR(FUNC) static void meta_##FUNC(struct sk_buff *skb, \
	struct tcf_pkt_info *info, struct meta_value *v, \
	struct meta_obj *dst, int *err)

/**************************************************************************
 * System status & misc
 **************************************************************************/

META_COLLECTOR(int_random)
{
	get_random_bytes(&dst->value, sizeof(dst->value));
}

static inline unsigned long fixed_loadavg(int load)
{
	int rnd_load = load + (FIXED_1/200);
	int rnd_frac = ((rnd_load & (FIXED_1-1)) * 100) >> FSHIFT;

	return ((rnd_load >> FSHIFT) * 100) + rnd_frac;
}

META_COLLECTOR(int_loadavg_0)
{
	dst->value = fixed_loadavg(avenrun[0]);
}

META_COLLECTOR(int_loadavg_1)
{
	dst->value = fixed_loadavg(avenrun[1]);
}

META_COLLECTOR(int_loadavg_2)
{
	dst->value = fixed_loadavg(avenrun[2]);
}

/**************************************************************************
 * Device names & indices
 **************************************************************************/

static inline int int_dev(struct net_device *dev, struct meta_obj *dst)
{
	if (unlikely(dev == NULL))
		return -1;

	dst->value = dev->ifindex;
	return 0;
}

static inline int var_dev(struct net_device *dev, struct meta_obj *dst)
{
	if (unlikely(dev == NULL))
		return -1;

	dst->value = (unsigned long) dev->name;
	dst->len = strlen(dev->name);
	return 0;
}

META_COLLECTOR(int_dev)
{
	*err = int_dev(skb->dev, dst);
}

META_COLLECTOR(var_dev)
{
	*err = var_dev(skb->dev, dst);
}

/**************************************************************************
 * skb attributes
 **************************************************************************/

META_COLLECTOR(int_priority)
{
	dst->value = skb->priority;
}

META_COLLECTOR(int_protocol)
{
	/* Let userspace take care of the byte ordering */
	dst->value = skb->protocol;
}

META_COLLECTOR(int_pkttype)
{
	dst->value = skb->pkt_type;
}

META_COLLECTOR(int_pktlen)
{
	dst->value = skb->len;
}

META_COLLECTOR(int_datalen)
{
	dst->value = skb->data_len;
}

META_COLLECTOR(int_maclen)
{
	dst->value = skb->mac_len;
}

/**************************************************************************
 * Netfilter
 **************************************************************************/

META_COLLECTOR(int_nfmark)
{
#ifdef CONFIG_NETFILTER
	dst->value = skb->nfmark;
#else
	dst->value = 0;
#endif
}

/**************************************************************************
 * Traffic Control
 **************************************************************************/

META_COLLECTOR(int_tcindex)
{
	dst->value = skb->tc_index;
}

/**************************************************************************
 * Routing
 **************************************************************************/

META_COLLECTOR(int_rtclassid)
{
	if (unlikely(skb->dst == NULL))
		*err = -1;
	else
#ifdef CONFIG_NET_CLS_ROUTE
		dst->value = skb->dst->tclassid;
#else
		dst->value = 0;
#endif
}

META_COLLECTOR(int_rtiif)
{
	if (unlikely(skb->dst == NULL))
		*err = -1;
	else
		dst->value = ((struct rtable*) skb->dst)->fl.iif;
}

/**************************************************************************
 * Socket Attributes
 **************************************************************************/

#define SKIP_NONLOCAL(skb)			\
	if (unlikely(skb->sk == NULL)) {	\
		*err = -1;			\
		return;				\
	}

META_COLLECTOR(int_sk_family)
{
	SKIP_NONLOCAL(skb);
	dst->value = skb->sk->sk_family;
}

META_COLLECTOR(int_sk_state)
{
	SKIP_NONLOCAL(skb);
	dst->value = skb->sk->sk_state;
}

META_COLLECTOR(int_sk_reuse)
{
	SKIP_NONLOCAL(skb);
	dst->value = skb->sk->sk_reuse;
}

META_COLLECTOR(int_sk_bound_if)
{
	SKIP_NONLOCAL(skb);
	/* No error if bound_dev_if is 0, legal userspace check */
	dst->value = skb->sk->sk_bound_dev_if;
}

META_COLLECTOR(var_sk_bound_if)
{
	SKIP_NONLOCAL(skb);

	 if (skb->sk->sk_bound_dev_if == 0) {
		dst->value = (unsigned long) "any";
		dst->len = 3;
	 } else  {
		struct net_device *dev;
		
		dev = dev_get_by_index(skb->sk->sk_bound_dev_if);
		*err = var_dev(dev, dst);
		if (dev)
			dev_put(dev);
	 }
}

META_COLLECTOR(int_sk_refcnt)
{
	SKIP_NONLOCAL(skb);
	dst->value = atomic_read(&skb->sk->sk_refcnt);
}

META_COLLECTOR(int_sk_rcvbuf)
{
	SKIP_NONLOCAL(skb);
	dst->value = skb->sk->sk_rcvbuf;
}

META_COLLECTOR(int_sk_shutdown)
{
	SKIP_NONLOCAL(skb);
	dst->value = skb->sk->sk_shutdown;
}

META_COLLECTOR(int_sk_proto)
{
	SKIP_NONLOCAL(skb);
	dst->value = skb->sk->sk_protocol;
}

META_COLLECTOR(int_sk_type)
{
	SKIP_NONLOCAL(skb);
	dst->value = skb->sk->sk_type;
}

META_COLLECTOR(int_sk_rmem_alloc)
{
	SKIP_NONLOCAL(skb);
	dst->value = atomic_read(&skb->sk->sk_rmem_alloc);
}

META_COLLECTOR(int_sk_wmem_alloc)
{
	SKIP_NONLOCAL(skb);
	dst->value = atomic_read(&skb->sk->sk_wmem_alloc);
}

META_COLLECTOR(int_sk_omem_alloc)
{
	SKIP_NONLOCAL(skb);
	dst->value = atomic_read(&skb->sk->sk_omem_alloc);
}

META_COLLECTOR(int_sk_rcv_qlen)
{
	SKIP_NONLOCAL(skb);
	dst->value = skb->sk->sk_receive_queue.qlen;
}

META_COLLECTOR(int_sk_snd_qlen)
{
	SKIP_NONLOCAL(skb);
	dst->value = skb->sk->sk_write_queue.qlen;
}

META_COLLECTOR(int_sk_wmem_queued)
{
	SKIP_NONLOCAL(skb);
	dst->value = skb->sk->sk_wmem_queued;
}

META_COLLECTOR(int_sk_fwd_alloc)
{
	SKIP_NONLOCAL(skb);
	dst->value = skb->sk->sk_forward_alloc;
}

META_COLLECTOR(int_sk_sndbuf)
{
	SKIP_NONLOCAL(skb);
	dst->value = skb->sk->sk_sndbuf;
}

META_COLLECTOR(int_sk_alloc)
{
	SKIP_NONLOCAL(skb);
	dst->value = skb->sk->sk_allocation;
}

META_COLLECTOR(int_sk_route_caps)
{
	SKIP_NONLOCAL(skb);
	dst->value = skb->sk->sk_route_caps;
}

META_COLLECTOR(int_sk_hash)
{
	SKIP_NONLOCAL(skb);
	dst->value = skb->sk->sk_hash;
}

META_COLLECTOR(int_sk_lingertime)
{
	SKIP_NONLOCAL(skb);
	dst->value = skb->sk->sk_lingertime / HZ;
}

META_COLLECTOR(int_sk_err_qlen)
{
	SKIP_NONLOCAL(skb);
	dst->value = skb->sk->sk_error_queue.qlen;
}

META_COLLECTOR(int_sk_ack_bl)
{
	SKIP_NONLOCAL(skb);
	dst->value = skb->sk->sk_ack_backlog;
}

META_COLLECTOR(int_sk_max_ack_bl)
{
	SKIP_NONLOCAL(skb);
	dst->value = skb->sk->sk_max_ack_backlog;
}

META_COLLECTOR(int_sk_prio)
{
	SKIP_NONLOCAL(skb);
	dst->value = skb->sk->sk_priority;
}

META_COLLECTOR(int_sk_rcvlowat)
{
	SKIP_NONLOCAL(skb);
	dst->value = skb->sk->sk_rcvlowat;
}

META_COLLECTOR(int_sk_rcvtimeo)
{
	SKIP_NONLOCAL(skb);
	dst->value = skb->sk->sk_rcvtimeo / HZ;
}

META_COLLECTOR(int_sk_sndtimeo)
{
	SKIP_NONLOCAL(skb);
	dst->value = skb->sk->sk_sndtimeo / HZ;
}

META_COLLECTOR(int_sk_sendmsg_off)
{
	SKIP_NONLOCAL(skb);
	dst->value = skb->sk->sk_sndmsg_off;
}

META_COLLECTOR(int_sk_write_pend)
{
	SKIP_NONLOCAL(skb);
	dst->value = skb->sk->sk_write_pending;
}

/**************************************************************************
 * Meta value collectors assignment table
 **************************************************************************/

struct meta_ops
{
	void		(*get)(struct sk_buff *, struct tcf_pkt_info *,
			       struct meta_value *, struct meta_obj *, int *);
};

#define META_ID(name) TCF_META_ID_##name
#define META_FUNC(name) { .get = meta_##name }

/* Meta value operations table listing all meta value collectors and
 * assigns them to a type and meta id. */
static struct meta_ops __meta_ops[TCF_META_TYPE_MAX+1][TCF_META_ID_MAX+1] = {
	[TCF_META_TYPE_VAR] = {
		[META_ID(DEV)]			= META_FUNC(var_dev),
		[META_ID(SK_BOUND_IF)] 		= META_FUNC(var_sk_bound_if),
	},
	[TCF_META_TYPE_INT] = {
		[META_ID(RANDOM)]		= META_FUNC(int_random),
		[META_ID(LOADAVG_0)]		= META_FUNC(int_loadavg_0),
		[META_ID(LOADAVG_1)]		= META_FUNC(int_loadavg_1),
		[META_ID(LOADAVG_2)]		= META_FUNC(int_loadavg_2),
		[META_ID(DEV)]			= META_FUNC(int_dev),
		[META_ID(PRIORITY)]		= META_FUNC(int_priority),
		[META_ID(PROTOCOL)]		= META_FUNC(int_protocol),
		[META_ID(PKTTYPE)]		= META_FUNC(int_pkttype),
		[META_ID(PKTLEN)]		= META_FUNC(int_pktlen),
		[META_ID(DATALEN)]		= META_FUNC(int_datalen),
		[META_ID(MACLEN)]		= META_FUNC(int_maclen),
		[META_ID(NFMARK)]		= META_FUNC(int_nfmark),
		[META_ID(TCINDEX)]		= META_FUNC(int_tcindex),
		[META_ID(RTCLASSID)]		= META_FUNC(int_rtclassid),
		[META_ID(RTIIF)]		= META_FUNC(int_rtiif),
		[META_ID(SK_FAMILY)]		= META_FUNC(int_sk_family),
		[META_ID(SK_STATE)]		= META_FUNC(int_sk_state),
		[META_ID(SK_REUSE)]		= META_FUNC(int_sk_reuse),
		[META_ID(SK_BOUND_IF)]		= META_FUNC(int_sk_bound_if),
		[META_ID(SK_REFCNT)]		= META_FUNC(int_sk_refcnt),
		[META_ID(SK_RCVBUF)]		= META_FUNC(int_sk_rcvbuf),
		[META_ID(SK_SNDBUF)]		= META_FUNC(int_sk_sndbuf),
		[META_ID(SK_SHUTDOWN)]		= META_FUNC(int_sk_shutdown),
		[META_ID(SK_PROTO)]		= META_FUNC(int_sk_proto),
		[META_ID(SK_TYPE)]		= META_FUNC(int_sk_type),
		[META_ID(SK_RMEM_ALLOC)]	= META_FUNC(int_sk_rmem_alloc),
		[META_ID(SK_WMEM_ALLOC)]	= META_FUNC(int_sk_wmem_alloc),
		[META_ID(SK_OMEM_ALLOC)]	= META_FUNC(int_sk_omem_alloc),
		[META_ID(SK_WMEM_QUEUED)]	= META_FUNC(int_sk_wmem_queued),
		[META_ID(SK_RCV_QLEN)]		= META_FUNC(int_sk_rcv_qlen),
		[META_ID(SK_SND_QLEN)]		= META_FUNC(int_sk_snd_qlen),
		[META_ID(SK_ERR_QLEN)]		= META_FUNC(int_sk_err_qlen),
		[META_ID(SK_FORWARD_ALLOCS)]	= META_FUNC(int_sk_fwd_alloc),
		[META_ID(SK_ALLOCS)]		= META_FUNC(int_sk_alloc),
		[META_ID(SK_ROUTE_CAPS)]	= META_FUNC(int_sk_route_caps),
		[META_ID(SK_HASH)]		= META_FUNC(int_sk_hash),
		[META_ID(SK_LINGERTIME)]	= META_FUNC(int_sk_lingertime),
		[META_ID(SK_ACK_BACKLOG)]	= META_FUNC(int_sk_ack_bl),
		[META_ID(SK_MAX_ACK_BACKLOG)]	= META_FUNC(int_sk_max_ack_bl),
		[META_ID(SK_PRIO)]		= META_FUNC(int_sk_prio),
		[META_ID(SK_RCVLOWAT)]		= META_FUNC(int_sk_rcvlowat),
		[META_ID(SK_RCVTIMEO)]		= META_FUNC(int_sk_rcvtimeo),
		[META_ID(SK_SNDTIMEO)]		= META_FUNC(int_sk_sndtimeo),
		[META_ID(SK_SENDMSG_OFF)]	= META_FUNC(int_sk_sendmsg_off),
		[META_ID(SK_WRITE_PENDING)]	= META_FUNC(int_sk_write_pend),
	}
};

static inline struct meta_ops * meta_ops(struct meta_value *val)
{
	return &__meta_ops[meta_type(val)][meta_id(val)];
}

/**************************************************************************
 * Type specific operations for TCF_META_TYPE_VAR
 **************************************************************************/

static int meta_var_compare(struct meta_obj *a, struct meta_obj *b)
{
	int r = a->len - b->len;

	if (r == 0)
		r = memcmp((void *) a->value, (void *) b->value, a->len);

	return r;
}

static int meta_var_change(struct meta_value *dst, struct rtattr *rta)
{
	int len = RTA_PAYLOAD(rta);

	dst->val = (unsigned long) kmalloc(len, GFP_KERNEL);
	if (dst->val == 0UL)
		return -ENOMEM;
	memcpy((void *) dst->val, RTA_DATA(rta), len);
	dst->len = len;
	return 0;
}

static void meta_var_destroy(struct meta_value *v)
{
	if (v->val)
		kfree((void *) v->val);
}

static void meta_var_apply_extras(struct meta_value *v,
				  struct meta_obj *dst)
{
	int shift = v->hdr.shift;

	if (shift && shift < dst->len)
		dst->len -= shift;
}

static int meta_var_dump(struct sk_buff *skb, struct meta_value *v, int tlv)
{
	if (v->val && v->len)
		RTA_PUT(skb, tlv, v->len, (void *) v->val);
	return 0;

rtattr_failure:
	return -1;
}

/**************************************************************************
 * Type specific operations for TCF_META_TYPE_INT
 **************************************************************************/

static int meta_int_compare(struct meta_obj *a, struct meta_obj *b)
{
	/* Let gcc optimize it, the unlikely is not really based on
	 * some numbers but jump free code for mismatches seems
	 * more logical. */
	if (unlikely(a->value == b->value))
		return 0;
	else if (a->value < b->value)
		return -1;
	else
		return 1;
}

static int meta_int_change(struct meta_value *dst, struct rtattr *rta)
{
	if (RTA_PAYLOAD(rta) >= sizeof(unsigned long)) {
		dst->val = *(unsigned long *) RTA_DATA(rta);
		dst->len = sizeof(unsigned long);
	} else if (RTA_PAYLOAD(rta) == sizeof(u32)) {
		dst->val = *(u32 *) RTA_DATA(rta);
		dst->len = sizeof(u32);
	} else
		return -EINVAL;

	return 0;
}

static void meta_int_apply_extras(struct meta_value *v,
				  struct meta_obj *dst)
{
	if (v->hdr.shift)
		dst->value >>= v->hdr.shift;

	if (v->val)
		dst->value &= v->val;
}

static int meta_int_dump(struct sk_buff *skb, struct meta_value *v, int tlv)
{
	if (v->len == sizeof(unsigned long))
		RTA_PUT(skb, tlv, sizeof(unsigned long), &v->val);
	else if (v->len == sizeof(u32)) {
		u32 d = v->val;
		RTA_PUT(skb, tlv, sizeof(d), &d);
	}

	return 0;

rtattr_failure:
	return -1;
}

/**************************************************************************
 * Type specific operations table
 **************************************************************************/

struct meta_type_ops
{
	void	(*destroy)(struct meta_value *);
	int	(*compare)(struct meta_obj *, struct meta_obj *);
	int	(*change)(struct meta_value *, struct rtattr *);
	void	(*apply_extras)(struct meta_value *, struct meta_obj *);
	int	(*dump)(struct sk_buff *, struct meta_value *, int);
};

static struct meta_type_ops __meta_type_ops[TCF_META_TYPE_MAX+1] = {
	[TCF_META_TYPE_VAR] = {
		.destroy = meta_var_destroy,
		.compare = meta_var_compare,
		.change = meta_var_change,
		.apply_extras = meta_var_apply_extras,
		.dump = meta_var_dump
	},
	[TCF_META_TYPE_INT] = {
		.compare = meta_int_compare,
		.change = meta_int_change,
		.apply_extras = meta_int_apply_extras,
		.dump = meta_int_dump
	}
};

static inline struct meta_type_ops * meta_type_ops(struct meta_value *v)
{
	return &__meta_type_ops[meta_type(v)];
}

/**************************************************************************
 * Core
 **************************************************************************/

static inline int meta_get(struct sk_buff *skb, struct tcf_pkt_info *info, 
			   struct meta_value *v, struct meta_obj *dst)
{
	int err = 0;

	if (meta_id(v) == TCF_META_ID_VALUE) {
		dst->value = v->val;
		dst->len = v->len;
		return 0;
	}

	meta_ops(v)->get(skb, info, v, dst, &err);
	if (err < 0)
		return err;

	if (meta_type_ops(v)->apply_extras)
	    meta_type_ops(v)->apply_extras(v, dst);

	return 0;
}

static int em_meta_match(struct sk_buff *skb, struct tcf_ematch *m,
			 struct tcf_pkt_info *info)
{
	int r;
	struct meta_match *meta = (struct meta_match *) m->data;
	struct meta_obj l_value, r_value;

	if (meta_get(skb, info, &meta->lvalue, &l_value) < 0 ||
	    meta_get(skb, info, &meta->rvalue, &r_value) < 0)
		return 0;

	r = meta_type_ops(&meta->lvalue)->compare(&l_value, &r_value);

	switch (meta->lvalue.hdr.op) {
		case TCF_EM_OPND_EQ:
			return !r;
		case TCF_EM_OPND_LT:
			return r < 0;
		case TCF_EM_OPND_GT:
			return r > 0;
	}

	return 0;
}

static inline void meta_delete(struct meta_match *meta)
{
	struct meta_type_ops *ops = meta_type_ops(&meta->lvalue);

	if (ops && ops->destroy) {
		ops->destroy(&meta->lvalue);
		ops->destroy(&meta->rvalue);
	}

	kfree(meta);
}

static inline int meta_change_data(struct meta_value *dst, struct rtattr *rta)
{
	if (rta) {
		if (RTA_PAYLOAD(rta) == 0)
			return -EINVAL;

		return meta_type_ops(dst)->change(dst, rta);
	}

	return 0;
}

static inline int meta_is_supported(struct meta_value *val)
{
	return (!meta_id(val) || meta_ops(val)->get);
}

static int em_meta_change(struct tcf_proto *tp, void *data, int len,
			  struct tcf_ematch *m)
{
	int err = -EINVAL;
	struct rtattr *tb[TCA_EM_META_MAX];
	struct tcf_meta_hdr *hdr;
	struct meta_match *meta = NULL;
	
	if (rtattr_parse(tb, TCA_EM_META_MAX, data, len) < 0)
		goto errout;

	if (tb[TCA_EM_META_HDR-1] == NULL ||
	    RTA_PAYLOAD(tb[TCA_EM_META_HDR-1]) < sizeof(*hdr))
		goto errout;
	hdr = RTA_DATA(tb[TCA_EM_META_HDR-1]);

	if (TCF_META_TYPE(hdr->left.kind) != TCF_META_TYPE(hdr->right.kind) ||
	    TCF_META_TYPE(hdr->left.kind) > TCF_META_TYPE_MAX ||
	    TCF_META_ID(hdr->left.kind) > TCF_META_ID_MAX ||
	    TCF_META_ID(hdr->right.kind) > TCF_META_ID_MAX)
		goto errout;

	meta = kmalloc(sizeof(*meta), GFP_KERNEL);
	if (meta == NULL)
		goto errout;
	memset(meta, 0, sizeof(*meta));

	memcpy(&meta->lvalue.hdr, &hdr->left, sizeof(hdr->left));
	memcpy(&meta->rvalue.hdr, &hdr->right, sizeof(hdr->right));

	if (!meta_is_supported(&meta->lvalue) ||
	    !meta_is_supported(&meta->rvalue)) {
		err = -EOPNOTSUPP;
		goto errout;
	}

	if (meta_change_data(&meta->lvalue, tb[TCA_EM_META_LVALUE-1]) < 0 ||
	    meta_change_data(&meta->rvalue, tb[TCA_EM_META_RVALUE-1]) < 0)
		goto errout;

	m->datalen = sizeof(*meta);
	m->data = (unsigned long) meta;

	err = 0;
errout:
	if (err && meta)
		meta_delete(meta);
	return err;
}

static void em_meta_destroy(struct tcf_proto *tp, struct tcf_ematch *m)
{
	if (m)
		meta_delete((struct meta_match *) m->data);
}

static int em_meta_dump(struct sk_buff *skb, struct tcf_ematch *em)
{
	struct meta_match *meta = (struct meta_match *) em->data;
	struct tcf_meta_hdr hdr;
	struct meta_type_ops *ops;

	memset(&hdr, 0, sizeof(hdr));
	memcpy(&hdr.left, &meta->lvalue.hdr, sizeof(hdr.left));
	memcpy(&hdr.right, &meta->rvalue.hdr, sizeof(hdr.right));

	RTA_PUT(skb, TCA_EM_META_HDR, sizeof(hdr), &hdr);

	ops = meta_type_ops(&meta->lvalue);
	if (ops->dump(skb, &meta->lvalue, TCA_EM_META_LVALUE) < 0 ||
	    ops->dump(skb, &meta->rvalue, TCA_EM_META_RVALUE) < 0)
		goto rtattr_failure;

	return 0;

rtattr_failure:
	return -1;
}		

static struct tcf_ematch_ops em_meta_ops = {
	.kind	  = TCF_EM_META,
	.change	  = em_meta_change,
	.match	  = em_meta_match,
	.destroy  = em_meta_destroy,
	.dump	  = em_meta_dump,
	.owner	  = THIS_MODULE,
	.link	  = LIST_HEAD_INIT(em_meta_ops.link)
};

static int __init init_em_meta(void)
{
	return tcf_em_register(&em_meta_ops);
}

static void __exit exit_em_meta(void) 
{
	tcf_em_unregister(&em_meta_ops);
}

MODULE_LICENSE("GPL");

module_init(init_em_meta);
module_exit(exit_em_meta);
OpenPOWER on IntegriCloud