summaryrefslogtreecommitdiffstats
path: root/net/sched/act_api.c
blob: a512b18c0088506bc577d8b3a1113871206c6d47 (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
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
/*
 * net/sched/act_api.c	Packet action API.
 *
 *		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.
 *
 * Author:	Jamal Hadi Salim
 *
 *
 */

#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/skbuff.h>
#include <linux/init.h>
#include <linux/kmod.h>
#include <linux/err.h>
#include <linux/module.h>
#include <net/net_namespace.h>
#include <net/sock.h>
#include <net/sch_generic.h>
#include <net/act_api.h>
#include <net/netlink.h>

static void free_tcf(struct rcu_head *head)
{
	struct tc_action *p = container_of(head, struct tc_action, tcfa_rcu);

	free_percpu(p->cpu_bstats);
	free_percpu(p->cpu_qstats);
	kfree(p);
}

static void tcf_hash_destroy(struct tcf_hashinfo *hinfo, struct tc_action *p)
{
	spin_lock_bh(&hinfo->lock);
	hlist_del(&p->tcfa_head);
	spin_unlock_bh(&hinfo->lock);
	gen_kill_estimator(&p->tcfa_bstats,
			   &p->tcfa_rate_est);
	/*
	 * gen_estimator est_timer() might access p->tcfa_lock
	 * or bstats, wait a RCU grace period before freeing p
	 */
	call_rcu(&p->tcfa_rcu, free_tcf);
}

int __tcf_hash_release(struct tc_action *p, bool bind, bool strict)
{
	int ret = 0;

	if (p) {
		if (bind)
			p->tcfa_bindcnt--;
		else if (strict && p->tcfa_bindcnt > 0)
			return -EPERM;

		p->tcfa_refcnt--;
		if (p->tcfa_bindcnt <= 0 && p->tcfa_refcnt <= 0) {
			if (p->ops->cleanup)
				p->ops->cleanup(p, bind);
			tcf_hash_destroy(p->hinfo, p);
			ret = ACT_P_DELETED;
		}
	}

	return ret;
}
EXPORT_SYMBOL(__tcf_hash_release);

static int tcf_dump_walker(struct tcf_hashinfo *hinfo, struct sk_buff *skb,
			   struct netlink_callback *cb)
{
	int err = 0, index = -1, i = 0, s_i = 0, n_i = 0;
	struct nlattr *nest;

	spin_lock_bh(&hinfo->lock);

	s_i = cb->args[0];

	for (i = 0; i < (hinfo->hmask + 1); i++) {
		struct hlist_head *head;
		struct tc_action *p;

		head = &hinfo->htab[tcf_hash(i, hinfo->hmask)];

		hlist_for_each_entry_rcu(p, head, tcfa_head) {
			index++;
			if (index < s_i)
				continue;

			nest = nla_nest_start(skb, n_i);
			if (nest == NULL)
				goto nla_put_failure;
			err = tcf_action_dump_1(skb, p, 0, 0);
			if (err < 0) {
				index--;
				nlmsg_trim(skb, nest);
				goto done;
			}
			nla_nest_end(skb, nest);
			n_i++;
			if (n_i >= TCA_ACT_MAX_PRIO)
				goto done;
		}
	}
done:
	spin_unlock_bh(&hinfo->lock);
	if (n_i)
		cb->args[0] += n_i;
	return n_i;

nla_put_failure:
	nla_nest_cancel(skb, nest);
	goto done;
}

static int tcf_del_walker(struct tcf_hashinfo *hinfo, struct sk_buff *skb,
			  const struct tc_action_ops *ops)
{
	struct nlattr *nest;
	int i = 0, n_i = 0;
	int ret = -EINVAL;

	nest = nla_nest_start(skb, 0);
	if (nest == NULL)
		goto nla_put_failure;
	if (nla_put_string(skb, TCA_KIND, ops->kind))
		goto nla_put_failure;
	for (i = 0; i < (hinfo->hmask + 1); i++) {
		struct hlist_head *head;
		struct hlist_node *n;
		struct tc_action *p;

		head = &hinfo->htab[tcf_hash(i, hinfo->hmask)];
		hlist_for_each_entry_safe(p, n, head, tcfa_head) {
			ret = __tcf_hash_release(p, false, true);
			if (ret == ACT_P_DELETED) {
				module_put(p->ops->owner);
				n_i++;
			} else if (ret < 0)
				goto nla_put_failure;
		}
	}
	if (nla_put_u32(skb, TCA_FCNT, n_i))
		goto nla_put_failure;
	nla_nest_end(skb, nest);

	return n_i;
nla_put_failure:
	nla_nest_cancel(skb, nest);
	return ret;
}

int tcf_generic_walker(struct tc_action_net *tn, struct sk_buff *skb,
		       struct netlink_callback *cb, int type,
		       const struct tc_action_ops *ops)
{
	struct tcf_hashinfo *hinfo = tn->hinfo;

	if (type == RTM_DELACTION) {
		return tcf_del_walker(hinfo, skb, ops);
	} else if (type == RTM_GETACTION) {
		return tcf_dump_walker(hinfo, skb, cb);
	} else {
		WARN(1, "tcf_generic_walker: unknown action %d\n", type);
		return -EINVAL;
	}
}
EXPORT_SYMBOL(tcf_generic_walker);

static struct tc_action *tcf_hash_lookup(u32 index, struct tcf_hashinfo *hinfo)
{
	struct tc_action *p = NULL;
	struct hlist_head *head;

	spin_lock_bh(&hinfo->lock);
	head = &hinfo->htab[tcf_hash(index, hinfo->hmask)];
	hlist_for_each_entry_rcu(p, head, tcfa_head)
		if (p->tcfa_index == index)
			break;
	spin_unlock_bh(&hinfo->lock);

	return p;
}

u32 tcf_hash_new_index(struct tc_action_net *tn)
{
	struct tcf_hashinfo *hinfo = tn->hinfo;
	u32 val = hinfo->index;

	do {
		if (++val == 0)
			val = 1;
	} while (tcf_hash_lookup(val, hinfo));

	hinfo->index = val;
	return val;
}
EXPORT_SYMBOL(tcf_hash_new_index);

int tcf_hash_search(struct tc_action_net *tn, struct tc_action **a, u32 index)
{
	struct tcf_hashinfo *hinfo = tn->hinfo;
	struct tc_action *p = tcf_hash_lookup(index, hinfo);

	if (p) {
		*a = p;
		return 1;
	}
	return 0;
}
EXPORT_SYMBOL(tcf_hash_search);

bool tcf_hash_check(struct tc_action_net *tn, u32 index, struct tc_action **a,
		    int bind)
{
	struct tcf_hashinfo *hinfo = tn->hinfo;
	struct tc_action *p = NULL;

	if (index && (p = tcf_hash_lookup(index, hinfo)) != NULL) {
		if (bind)
			p->tcfa_bindcnt++;
		p->tcfa_refcnt++;
		*a = p;
		return true;
	}
	return false;
}
EXPORT_SYMBOL(tcf_hash_check);

void tcf_hash_cleanup(struct tc_action *a, struct nlattr *est)
{
	if (est)
		gen_kill_estimator(&a->tcfa_bstats,
				   &a->tcfa_rate_est);
	call_rcu(&a->tcfa_rcu, free_tcf);
}
EXPORT_SYMBOL(tcf_hash_cleanup);

int tcf_hash_create(struct tc_action_net *tn, u32 index, struct nlattr *est,
		    struct tc_action **a, const struct tc_action_ops *ops,
		    int bind, bool cpustats)
{
	struct tc_action *p = kzalloc(ops->size, GFP_KERNEL);
	struct tcf_hashinfo *hinfo = tn->hinfo;
	int err = -ENOMEM;

	if (unlikely(!p))
		return -ENOMEM;
	p->tcfa_refcnt = 1;
	if (bind)
		p->tcfa_bindcnt = 1;

	if (cpustats) {
		p->cpu_bstats = netdev_alloc_pcpu_stats(struct gnet_stats_basic_cpu);
		if (!p->cpu_bstats) {
err1:
			kfree(p);
			return err;
		}
		p->cpu_qstats = alloc_percpu(struct gnet_stats_queue);
		if (!p->cpu_qstats) {
err2:
			free_percpu(p->cpu_bstats);
			goto err1;
		}
	}
	spin_lock_init(&p->tcfa_lock);
	INIT_HLIST_NODE(&p->tcfa_head);
	p->tcfa_index = index ? index : tcf_hash_new_index(tn);
	p->tcfa_tm.install = jiffies;
	p->tcfa_tm.lastuse = jiffies;
	p->tcfa_tm.firstuse = 0;
	if (est) {
		err = gen_new_estimator(&p->tcfa_bstats, p->cpu_bstats,
					&p->tcfa_rate_est,
					&p->tcfa_lock, NULL, est);
		if (err) {
			free_percpu(p->cpu_qstats);
			goto err2;
		}
	}

	p->hinfo = hinfo;
	p->ops = ops;
	INIT_LIST_HEAD(&p->list);
	*a = p;
	return 0;
}
EXPORT_SYMBOL(tcf_hash_create);

void tcf_hash_insert(struct tc_action_net *tn, struct tc_action *a)
{
	struct tcf_hashinfo *hinfo = tn->hinfo;
	unsigned int h = tcf_hash(a->tcfa_index, hinfo->hmask);

	spin_lock_bh(&hinfo->lock);
	hlist_add_head(&a->tcfa_head, &hinfo->htab[h]);
	spin_unlock_bh(&hinfo->lock);
}
EXPORT_SYMBOL(tcf_hash_insert);

void tcf_hashinfo_destroy(const struct tc_action_ops *ops,
			  struct tcf_hashinfo *hinfo)
{
	int i;

	for (i = 0; i < hinfo->hmask + 1; i++) {
		struct tc_action *p;
		struct hlist_node *n;

		hlist_for_each_entry_safe(p, n, &hinfo->htab[i], tcfa_head) {
			int ret;

			ret = __tcf_hash_release(p, false, true);
			if (ret == ACT_P_DELETED)
				module_put(ops->owner);
			else if (ret < 0)
				return;
		}
	}
	kfree(hinfo->htab);
}
EXPORT_SYMBOL(tcf_hashinfo_destroy);

static LIST_HEAD(act_base);
static DEFINE_RWLOCK(act_mod_lock);

int tcf_register_action(struct tc_action_ops *act,
			struct pernet_operations *ops)
{
	struct tc_action_ops *a;
	int ret;

	if (!act->act || !act->dump || !act->init || !act->walk || !act->lookup)
		return -EINVAL;

	/* We have to register pernet ops before making the action ops visible,
	 * otherwise tcf_action_init_1() could get a partially initialized
	 * netns.
	 */
	ret = register_pernet_subsys(ops);
	if (ret)
		return ret;

	write_lock(&act_mod_lock);
	list_for_each_entry(a, &act_base, head) {
		if (act->type == a->type || (strcmp(act->kind, a->kind) == 0)) {
			write_unlock(&act_mod_lock);
			unregister_pernet_subsys(ops);
			return -EEXIST;
		}
	}
	list_add_tail(&act->head, &act_base);
	write_unlock(&act_mod_lock);

	return 0;
}
EXPORT_SYMBOL(tcf_register_action);

int tcf_unregister_action(struct tc_action_ops *act,
			  struct pernet_operations *ops)
{
	struct tc_action_ops *a;
	int err = -ENOENT;

	write_lock(&act_mod_lock);
	list_for_each_entry(a, &act_base, head) {
		if (a == act) {
			list_del(&act->head);
			err = 0;
			break;
		}
	}
	write_unlock(&act_mod_lock);
	if (!err)
		unregister_pernet_subsys(ops);
	return err;
}
EXPORT_SYMBOL(tcf_unregister_action);

/* lookup by name */
static struct tc_action_ops *tc_lookup_action_n(char *kind)
{
	struct tc_action_ops *a, *res = NULL;

	if (kind) {
		read_lock(&act_mod_lock);
		list_for_each_entry(a, &act_base, head) {
			if (strcmp(kind, a->kind) == 0) {
				if (try_module_get(a->owner))
					res = a;
				break;
			}
		}
		read_unlock(&act_mod_lock);
	}
	return res;
}

/* lookup by nlattr */
static struct tc_action_ops *tc_lookup_action(struct nlattr *kind)
{
	struct tc_action_ops *a, *res = NULL;

	if (kind) {
		read_lock(&act_mod_lock);
		list_for_each_entry(a, &act_base, head) {
			if (nla_strcmp(kind, a->kind) == 0) {
				if (try_module_get(a->owner))
					res = a;
				break;
			}
		}
		read_unlock(&act_mod_lock);
	}
	return res;
}

int tcf_action_exec(struct sk_buff *skb, struct tc_action **actions,
		    int nr_actions, struct tcf_result *res)
{
	int ret = -1, i;

	if (skb->tc_verd & TC_NCLS) {
		skb->tc_verd = CLR_TC_NCLS(skb->tc_verd);
		ret = TC_ACT_OK;
		goto exec_done;
	}
	for (i = 0; i < nr_actions; i++) {
		const struct tc_action *a = actions[i];

repeat:
		ret = a->ops->act(skb, a, res);
		if (ret == TC_ACT_REPEAT)
			goto repeat;	/* we need a ttl - JHS */
		if (ret != TC_ACT_PIPE)
			goto exec_done;
	}
exec_done:
	return ret;
}
EXPORT_SYMBOL(tcf_action_exec);

int tcf_action_destroy(struct list_head *actions, int bind)
{
	struct tc_action *a, *tmp;
	int ret = 0;

	list_for_each_entry_safe(a, tmp, actions, list) {
		ret = __tcf_hash_release(a, bind, true);
		if (ret == ACT_P_DELETED)
			module_put(a->ops->owner);
		else if (ret < 0)
			return ret;
	}
	return ret;
}

int
tcf_action_dump_old(struct sk_buff *skb, struct tc_action *a, int bind, int ref)
{
	return a->ops->dump(skb, a, bind, ref);
}

int
tcf_action_dump_1(struct sk_buff *skb, struct tc_action *a, int bind, int ref)
{
	int err = -EINVAL;
	unsigned char *b = skb_tail_pointer(skb);
	struct nlattr *nest;

	if (nla_put_string(skb, TCA_KIND, a->ops->kind))
		goto nla_put_failure;
	if (tcf_action_copy_stats(skb, a, 0))
		goto nla_put_failure;
	nest = nla_nest_start(skb, TCA_OPTIONS);
	if (nest == NULL)
		goto nla_put_failure;
	err = tcf_action_dump_old(skb, a, bind, ref);
	if (err > 0) {
		nla_nest_end(skb, nest);
		return err;
	}

nla_put_failure:
	nlmsg_trim(skb, b);
	return -1;
}
EXPORT_SYMBOL(tcf_action_dump_1);

int tcf_action_dump(struct sk_buff *skb, struct list_head *actions,
		    int bind, int ref)
{
	struct tc_action *a;
	int err = -EINVAL;
	struct nlattr *nest;

	list_for_each_entry(a, actions, list) {
		nest = nla_nest_start(skb, a->order);
		if (nest == NULL)
			goto nla_put_failure;
		err = tcf_action_dump_1(skb, a, bind, ref);
		if (err < 0)
			goto errout;
		nla_nest_end(skb, nest);
	}

	return 0;

nla_put_failure:
	err = -EINVAL;
errout:
	nla_nest_cancel(skb, nest);
	return err;
}

struct tc_action *tcf_action_init_1(struct net *net, struct nlattr *nla,
				    struct nlattr *est, char *name, int ovr,
				    int bind)
{
	struct tc_action *a;
	struct tc_action_ops *a_o;
	char act_name[IFNAMSIZ];
	struct nlattr *tb[TCA_ACT_MAX + 1];
	struct nlattr *kind;
	int err;

	if (name == NULL) {
		err = nla_parse_nested(tb, TCA_ACT_MAX, nla, NULL);
		if (err < 0)
			goto err_out;
		err = -EINVAL;
		kind = tb[TCA_ACT_KIND];
		if (kind == NULL)
			goto err_out;
		if (nla_strlcpy(act_name, kind, IFNAMSIZ) >= IFNAMSIZ)
			goto err_out;
	} else {
		err = -EINVAL;
		if (strlcpy(act_name, name, IFNAMSIZ) >= IFNAMSIZ)
			goto err_out;
	}

	a_o = tc_lookup_action_n(act_name);
	if (a_o == NULL) {
#ifdef CONFIG_MODULES
		rtnl_unlock();
		request_module("act_%s", act_name);
		rtnl_lock();

		a_o = tc_lookup_action_n(act_name);

		/* We dropped the RTNL semaphore in order to
		 * perform the module load.  So, even if we
		 * succeeded in loading the module we have to
		 * tell the caller to replay the request.  We
		 * indicate this using -EAGAIN.
		 */
		if (a_o != NULL) {
			err = -EAGAIN;
			goto err_mod;
		}
#endif
		err = -ENOENT;
		goto err_out;
	}

	/* backward compatibility for policer */
	if (name == NULL)
		err = a_o->init(net, tb[TCA_ACT_OPTIONS], est, &a, ovr, bind);
	else
		err = a_o->init(net, nla, est, &a, ovr, bind);
	if (err < 0)
		goto err_mod;

	/* module count goes up only when brand new policy is created
	 * if it exists and is only bound to in a_o->init() then
	 * ACT_P_CREATED is not returned (a zero is).
	 */
	if (err != ACT_P_CREATED)
		module_put(a_o->owner);

	return a;

err_mod:
	module_put(a_o->owner);
err_out:
	return ERR_PTR(err);
}

static void cleanup_a(struct list_head *actions, int ovr)
{
	struct tc_action *a;

	if (!ovr)
		return;

	list_for_each_entry(a, actions, list)
		a->tcfa_refcnt--;
}

int tcf_action_init(struct net *net, struct nlattr *nla, struct nlattr *est,
		    char *name, int ovr, int bind, struct list_head *actions)
{
	struct nlattr *tb[TCA_ACT_MAX_PRIO + 1];
	struct tc_action *act;
	int err;
	int i;

	err = nla_parse_nested(tb, TCA_ACT_MAX_PRIO, nla, NULL);
	if (err < 0)
		return err;

	for (i = 1; i <= TCA_ACT_MAX_PRIO && tb[i]; i++) {
		act = tcf_action_init_1(net, tb[i], est, name, ovr, bind);
		if (IS_ERR(act)) {
			err = PTR_ERR(act);
			goto err;
		}
		act->order = i;
		if (ovr)
			act->tcfa_refcnt++;
		list_add_tail(&act->list, actions);
	}

	/* Remove the temp refcnt which was necessary to protect against
	 * destroying an existing action which was being replaced
	 */
	cleanup_a(actions, ovr);
	return 0;

err:
	tcf_action_destroy(actions, bind);
	return err;
}

int tcf_action_copy_stats(struct sk_buff *skb, struct tc_action *p,
			  int compat_mode)
{
	int err = 0;
	struct gnet_dump d;

	if (p == NULL)
		goto errout;

	/* compat_mode being true specifies a call that is supposed
	 * to add additional backward compatibility statistic TLVs.
	 */
	if (compat_mode) {
		if (p->type == TCA_OLD_COMPAT)
			err = gnet_stats_start_copy_compat(skb, 0,
							   TCA_STATS,
							   TCA_XSTATS,
							   &p->tcfa_lock, &d,
							   TCA_PAD);
		else
			return 0;
	} else
		err = gnet_stats_start_copy(skb, TCA_ACT_STATS,
					    &p->tcfa_lock, &d, TCA_ACT_PAD);

	if (err < 0)
		goto errout;

	if (gnet_stats_copy_basic(NULL, &d, p->cpu_bstats, &p->tcfa_bstats) < 0 ||
	    gnet_stats_copy_rate_est(&d, &p->tcfa_bstats,
				     &p->tcfa_rate_est) < 0 ||
	    gnet_stats_copy_queue(&d, p->cpu_qstats,
				  &p->tcfa_qstats,
				  p->tcfa_qstats.qlen) < 0)
		goto errout;

	if (gnet_stats_finish_copy(&d) < 0)
		goto errout;

	return 0;

errout:
	return -1;
}

static int tca_get_fill(struct sk_buff *skb, struct list_head *actions,
			u32 portid, u32 seq, u16 flags, int event, int bind,
			int ref)
{
	struct tcamsg *t;
	struct nlmsghdr *nlh;
	unsigned char *b = skb_tail_pointer(skb);
	struct nlattr *nest;

	nlh = nlmsg_put(skb, portid, seq, event, sizeof(*t), flags);
	if (!nlh)
		goto out_nlmsg_trim;
	t = nlmsg_data(nlh);
	t->tca_family = AF_UNSPEC;
	t->tca__pad1 = 0;
	t->tca__pad2 = 0;

	nest = nla_nest_start(skb, TCA_ACT_TAB);
	if (nest == NULL)
		goto out_nlmsg_trim;

	if (tcf_action_dump(skb, actions, bind, ref) < 0)
		goto out_nlmsg_trim;

	nla_nest_end(skb, nest);

	nlh->nlmsg_len = skb_tail_pointer(skb) - b;
	return skb->len;

out_nlmsg_trim:
	nlmsg_trim(skb, b);
	return -1;
}

static int
act_get_notify(struct net *net, u32 portid, struct nlmsghdr *n,
	       struct list_head *actions, int event)
{
	struct sk_buff *skb;

	skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
	if (!skb)
		return -ENOBUFS;
	if (tca_get_fill(skb, actions, portid, n->nlmsg_seq, 0, event,
			 0, 0) <= 0) {
		kfree_skb(skb);
		return -EINVAL;
	}

	return rtnl_unicast(skb, net, portid);
}

static struct tc_action *tcf_action_get_1(struct net *net, struct nlattr *nla,
					  struct nlmsghdr *n, u32 portid)
{
	struct nlattr *tb[TCA_ACT_MAX + 1];
	const struct tc_action_ops *ops;
	struct tc_action *a;
	int index;
	int err;

	err = nla_parse_nested(tb, TCA_ACT_MAX, nla, NULL);
	if (err < 0)
		goto err_out;

	err = -EINVAL;
	if (tb[TCA_ACT_INDEX] == NULL ||
	    nla_len(tb[TCA_ACT_INDEX]) < sizeof(index))
		goto err_out;
	index = nla_get_u32(tb[TCA_ACT_INDEX]);

	err = -EINVAL;
	ops = tc_lookup_action(tb[TCA_ACT_KIND]);
	if (!ops) /* could happen in batch of actions */
		goto err_out;
	err = -ENOENT;
	if (ops->lookup(net, &a, index) == 0)
		goto err_mod;

	module_put(ops->owner);
	return a;

err_mod:
	module_put(ops->owner);
err_out:
	return ERR_PTR(err);
}

static int tca_action_flush(struct net *net, struct nlattr *nla,
			    struct nlmsghdr *n, u32 portid)
{
	struct sk_buff *skb;
	unsigned char *b;
	struct nlmsghdr *nlh;
	struct tcamsg *t;
	struct netlink_callback dcb;
	struct nlattr *nest;
	struct nlattr *tb[TCA_ACT_MAX + 1];
	const struct tc_action_ops *ops;
	struct nlattr *kind;
	int err = -ENOMEM;

	skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
	if (!skb) {
		pr_debug("tca_action_flush: failed skb alloc\n");
		return err;
	}

	b = skb_tail_pointer(skb);

	err = nla_parse_nested(tb, TCA_ACT_MAX, nla, NULL);
	if (err < 0)
		goto err_out;

	err = -EINVAL;
	kind = tb[TCA_ACT_KIND];
	ops = tc_lookup_action(kind);
	if (!ops) /*some idjot trying to flush unknown action */
		goto err_out;

	nlh = nlmsg_put(skb, portid, n->nlmsg_seq, RTM_DELACTION,
			sizeof(*t), 0);
	if (!nlh)
		goto out_module_put;
	t = nlmsg_data(nlh);
	t->tca_family = AF_UNSPEC;
	t->tca__pad1 = 0;
	t->tca__pad2 = 0;

	nest = nla_nest_start(skb, TCA_ACT_TAB);
	if (nest == NULL)
		goto out_module_put;

	err = ops->walk(net, skb, &dcb, RTM_DELACTION, ops);
	if (err < 0)
		goto out_module_put;
	if (err == 0)
		goto noflush_out;

	nla_nest_end(skb, nest);

	nlh->nlmsg_len = skb_tail_pointer(skb) - b;
	nlh->nlmsg_flags |= NLM_F_ROOT;
	module_put(ops->owner);
	err = rtnetlink_send(skb, net, portid, RTNLGRP_TC,
			     n->nlmsg_flags & NLM_F_ECHO);
	if (err > 0)
		return 0;

	return err;

out_module_put:
	module_put(ops->owner);
err_out:
noflush_out:
	kfree_skb(skb);
	return err;
}

static int
tcf_del_notify(struct net *net, struct nlmsghdr *n, struct list_head *actions,
	       u32 portid)
{
	int ret;
	struct sk_buff *skb;

	skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
	if (!skb)
		return -ENOBUFS;

	if (tca_get_fill(skb, actions, portid, n->nlmsg_seq, 0, RTM_DELACTION,
			 0, 1) <= 0) {
		kfree_skb(skb);
		return -EINVAL;
	}

	/* now do the delete */
	ret = tcf_action_destroy(actions, 0);
	if (ret < 0) {
		kfree_skb(skb);
		return ret;
	}

	ret = rtnetlink_send(skb, net, portid, RTNLGRP_TC,
			     n->nlmsg_flags & NLM_F_ECHO);
	if (ret > 0)
		return 0;
	return ret;
}

static int
tca_action_gd(struct net *net, struct nlattr *nla, struct nlmsghdr *n,
	      u32 portid, int event)
{
	int i, ret;
	struct nlattr *tb[TCA_ACT_MAX_PRIO + 1];
	struct tc_action *act;
	LIST_HEAD(actions);

	ret = nla_parse_nested(tb, TCA_ACT_MAX_PRIO, nla, NULL);
	if (ret < 0)
		return ret;

	if (event == RTM_DELACTION && n->nlmsg_flags & NLM_F_ROOT) {
		if (tb[1] != NULL)
			return tca_action_flush(net, tb[1], n, portid);
		else
			return -EINVAL;
	}

	for (i = 1; i <= TCA_ACT_MAX_PRIO && tb[i]; i++) {
		act = tcf_action_get_1(net, tb[i], n, portid);
		if (IS_ERR(act)) {
			ret = PTR_ERR(act);
			goto err;
		}
		act->order = i;
		if (event == RTM_GETACTION)
			act->tcfa_refcnt++;
		list_add_tail(&act->list, &actions);
	}

	if (event == RTM_GETACTION)
		ret = act_get_notify(net, portid, n, &actions, event);
	else { /* delete */
		ret = tcf_del_notify(net, n, &actions, portid);
		if (ret)
			goto err;
		return ret;
	}
err:
	tcf_action_destroy(&actions, 0);
	return ret;
}

static int
tcf_add_notify(struct net *net, struct nlmsghdr *n, struct list_head *actions,
	       u32 portid)
{
	struct sk_buff *skb;
	int err = 0;

	skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
	if (!skb)
		return -ENOBUFS;

	if (tca_get_fill(skb, actions, portid, n->nlmsg_seq, n->nlmsg_flags,
			 RTM_NEWACTION, 0, 0) <= 0) {
		kfree_skb(skb);
		return -EINVAL;
	}

	err = rtnetlink_send(skb, net, portid, RTNLGRP_TC,
			     n->nlmsg_flags & NLM_F_ECHO);
	if (err > 0)
		err = 0;
	return err;
}

static int tcf_action_add(struct net *net, struct nlattr *nla,
			  struct nlmsghdr *n, u32 portid, int ovr)
{
	int ret = 0;
	LIST_HEAD(actions);

	ret = tcf_action_init(net, nla, NULL, NULL, ovr, 0, &actions);
	if (ret)
		return ret;

	return tcf_add_notify(net, n, &actions, portid);
}

static int tc_ctl_action(struct sk_buff *skb, struct nlmsghdr *n)
{
	struct net *net = sock_net(skb->sk);
	struct nlattr *tca[TCA_ACT_MAX + 1];
	u32 portid = skb ? NETLINK_CB(skb).portid : 0;
	int ret = 0, ovr = 0;

	if ((n->nlmsg_type != RTM_GETACTION) &&
	    !netlink_capable(skb, CAP_NET_ADMIN))
		return -EPERM;

	ret = nlmsg_parse(n, sizeof(struct tcamsg), tca, TCA_ACT_MAX, NULL);
	if (ret < 0)
		return ret;

	if (tca[TCA_ACT_TAB] == NULL) {
		pr_notice("tc_ctl_action: received NO action attribs\n");
		return -EINVAL;
	}

	/* n->nlmsg_flags & NLM_F_CREATE */
	switch (n->nlmsg_type) {
	case RTM_NEWACTION:
		/* we are going to assume all other flags
		 * imply create only if it doesn't exist
		 * Note that CREATE | EXCL implies that
		 * but since we want avoid ambiguity (eg when flags
		 * is zero) then just set this
		 */
		if (n->nlmsg_flags & NLM_F_REPLACE)
			ovr = 1;
replay:
		ret = tcf_action_add(net, tca[TCA_ACT_TAB], n, portid, ovr);
		if (ret == -EAGAIN)
			goto replay;
		break;
	case RTM_DELACTION:
		ret = tca_action_gd(net, tca[TCA_ACT_TAB], n,
				    portid, RTM_DELACTION);
		break;
	case RTM_GETACTION:
		ret = tca_action_gd(net, tca[TCA_ACT_TAB], n,
				    portid, RTM_GETACTION);
		break;
	default:
		BUG();
	}

	return ret;
}

static struct nlattr *find_dump_kind(const struct nlmsghdr *n)
{
	struct nlattr *tb1, *tb2[TCA_ACT_MAX + 1];
	struct nlattr *tb[TCA_ACT_MAX_PRIO + 1];
	struct nlattr *nla[TCAA_MAX + 1];
	struct nlattr *kind;

	if (nlmsg_parse(n, sizeof(struct tcamsg), nla, TCAA_MAX, NULL) < 0)
		return NULL;
	tb1 = nla[TCA_ACT_TAB];
	if (tb1 == NULL)
		return NULL;

	if (nla_parse(tb, TCA_ACT_MAX_PRIO, nla_data(tb1),
		      NLMSG_ALIGN(nla_len(tb1)), NULL) < 0)
		return NULL;

	if (tb[1] == NULL)
		return NULL;
	if (nla_parse(tb2, TCA_ACT_MAX, nla_data(tb[1]),
		      nla_len(tb[1]), NULL) < 0)
		return NULL;
	kind = tb2[TCA_ACT_KIND];

	return kind;
}

static int tc_dump_action(struct sk_buff *skb, struct netlink_callback *cb)
{
	struct net *net = sock_net(skb->sk);
	struct nlmsghdr *nlh;
	unsigned char *b = skb_tail_pointer(skb);
	struct nlattr *nest;
	struct tc_action_ops *a_o;
	int ret = 0;
	struct tcamsg *t = (struct tcamsg *) nlmsg_data(cb->nlh);
	struct nlattr *kind = find_dump_kind(cb->nlh);

	if (kind == NULL) {
		pr_info("tc_dump_action: action bad kind\n");
		return 0;
	}

	a_o = tc_lookup_action(kind);
	if (a_o == NULL)
		return 0;

	nlh = nlmsg_put(skb, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq,
			cb->nlh->nlmsg_type, sizeof(*t), 0);
	if (!nlh)
		goto out_module_put;
	t = nlmsg_data(nlh);
	t->tca_family = AF_UNSPEC;
	t->tca__pad1 = 0;
	t->tca__pad2 = 0;

	nest = nla_nest_start(skb, TCA_ACT_TAB);
	if (nest == NULL)
		goto out_module_put;

	ret = a_o->walk(net, skb, cb, RTM_GETACTION, a_o);
	if (ret < 0)
		goto out_module_put;

	if (ret > 0) {
		nla_nest_end(skb, nest);
		ret = skb->len;
	} else
		nlmsg_trim(skb, b);

	nlh->nlmsg_len = skb_tail_pointer(skb) - b;
	if (NETLINK_CB(cb->skb).portid && ret)
		nlh->nlmsg_flags |= NLM_F_MULTI;
	module_put(a_o->owner);
	return skb->len;

out_module_put:
	module_put(a_o->owner);
	nlmsg_trim(skb, b);
	return skb->len;
}

static int __init tc_action_init(void)
{
	rtnl_register(PF_UNSPEC, RTM_NEWACTION, tc_ctl_action, NULL, NULL);
	rtnl_register(PF_UNSPEC, RTM_DELACTION, tc_ctl_action, NULL, NULL);
	rtnl_register(PF_UNSPEC, RTM_GETACTION, tc_ctl_action, tc_dump_action,
		      NULL);

	return 0;
}

subsys_initcall(tc_action_init);