Bootlin logo

Elixir Cross Referencer

  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
/*
 * This is a module which is used for queueing packets and communicating with
 * userspace via nfnetlink.
 *
 * (C) 2005 by Harald Welte <laforge@netfilter.org>
 * (C) 2007 by Patrick McHardy <kaber@trash.net>
 *
 * Based on the old ipv4-only ip_queue.c:
 * (C) 2000-2002 James Morris <jmorris@intercode.com.au>
 * (C) 2003-2005 Netfilter Core Team <coreteam@netfilter.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 */
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/slab.h>
#include <linux/notifier.h>
#include <linux/netdevice.h>
#include <linux/netfilter.h>
#include <linux/proc_fs.h>
#include <linux/netfilter_ipv4.h>
#include <linux/netfilter_ipv6.h>
#include <linux/netfilter/nfnetlink.h>
#include <linux/netfilter/nfnetlink_queue.h>
#include <linux/list.h>
#include <net/sock.h>
#include <net/netfilter/nf_queue.h>

#include <asm/atomic.h>

#ifdef CONFIG_BRIDGE_NETFILTER
#include "../bridge/br_private.h"
#endif

#define NFQNL_QMAX_DEFAULT 1024

struct nfqnl_instance {
	struct hlist_node hlist;		/* global list of queues */
	struct rcu_head rcu;

	int peer_pid;
	unsigned int queue_maxlen;
	unsigned int copy_range;
	unsigned int queue_dropped;
	unsigned int queue_user_dropped;


	u_int16_t queue_num;			/* number of this queue */
	u_int8_t copy_mode;
/*
 * Following fields are dirtied for each queued packet,
 * keep them in same cache line if possible.
 */
	spinlock_t	lock;
	unsigned int	queue_total;
	atomic_t	id_sequence;		/* 'sequence' of pkt ids */
	struct list_head queue_list;		/* packets in queue */
};

typedef int (*nfqnl_cmpfn)(struct nf_queue_entry *, unsigned long);

static DEFINE_SPINLOCK(instances_lock);

#define INSTANCE_BUCKETS	16
static struct hlist_head instance_table[INSTANCE_BUCKETS] __read_mostly;

static inline u_int8_t instance_hashfn(u_int16_t queue_num)
{
	return ((queue_num >> 8) | queue_num) % INSTANCE_BUCKETS;
}

static struct nfqnl_instance *
instance_lookup(u_int16_t queue_num)
{
	struct hlist_head *head;
	struct hlist_node *pos;
	struct nfqnl_instance *inst;

	head = &instance_table[instance_hashfn(queue_num)];
	hlist_for_each_entry_rcu(inst, pos, head, hlist) {
		if (inst->queue_num == queue_num)
			return inst;
	}
	return NULL;
}

static struct nfqnl_instance *
instance_create(u_int16_t queue_num, int pid)
{
	struct nfqnl_instance *inst;
	unsigned int h;
	int err;

	spin_lock(&instances_lock);
	if (instance_lookup(queue_num)) {
		err = -EEXIST;
		goto out_unlock;
	}

	inst = kzalloc(sizeof(*inst), GFP_ATOMIC);
	if (!inst) {
		err = -ENOMEM;
		goto out_unlock;
	}

	inst->queue_num = queue_num;
	inst->peer_pid = pid;
	inst->queue_maxlen = NFQNL_QMAX_DEFAULT;
	inst->copy_range = 0xfffff;
	inst->copy_mode = NFQNL_COPY_NONE;
	spin_lock_init(&inst->lock);
	INIT_LIST_HEAD(&inst->queue_list);

	if (!try_module_get(THIS_MODULE)) {
		err = -EAGAIN;
		goto out_free;
	}

	h = instance_hashfn(queue_num);
	hlist_add_head_rcu(&inst->hlist, &instance_table[h]);

	spin_unlock(&instances_lock);

	return inst;

out_free:
	kfree(inst);
out_unlock:
	spin_unlock(&instances_lock);
	return ERR_PTR(err);
}

static void nfqnl_flush(struct nfqnl_instance *queue, nfqnl_cmpfn cmpfn,
			unsigned long data);

static void
instance_destroy_rcu(struct rcu_head *head)
{
	struct nfqnl_instance *inst = container_of(head, struct nfqnl_instance,
						   rcu);

	nfqnl_flush(inst, NULL, 0);
	kfree(inst);
	module_put(THIS_MODULE);
}

static void
__instance_destroy(struct nfqnl_instance *inst)
{
	hlist_del_rcu(&inst->hlist);
	call_rcu(&inst->rcu, instance_destroy_rcu);
}

static void
instance_destroy(struct nfqnl_instance *inst)
{
	spin_lock(&instances_lock);
	__instance_destroy(inst);
	spin_unlock(&instances_lock);
}

static inline void
__enqueue_entry(struct nfqnl_instance *queue, struct nf_queue_entry *entry)
{
       list_add_tail(&entry->list, &queue->queue_list);
       queue->queue_total++;
}

static struct nf_queue_entry *
find_dequeue_entry(struct nfqnl_instance *queue, unsigned int id)
{
	struct nf_queue_entry *entry = NULL, *i;

	spin_lock_bh(&queue->lock);

	list_for_each_entry(i, &queue->queue_list, list) {
		if (i->id == id) {
			entry = i;
			break;
		}
	}

	if (entry) {
		list_del(&entry->list);
		queue->queue_total--;
	}

	spin_unlock_bh(&queue->lock);

	return entry;
}

static void
nfqnl_flush(struct nfqnl_instance *queue, nfqnl_cmpfn cmpfn, unsigned long data)
{
	struct nf_queue_entry *entry, *next;

	spin_lock_bh(&queue->lock);
	list_for_each_entry_safe(entry, next, &queue->queue_list, list) {
		if (!cmpfn || cmpfn(entry, data)) {
			list_del(&entry->list);
			queue->queue_total--;
			nf_reinject(entry, NF_DROP);
		}
	}
	spin_unlock_bh(&queue->lock);
}

static struct sk_buff *
nfqnl_build_packet_message(struct nfqnl_instance *queue,
			   struct nf_queue_entry *entry)
{
	sk_buff_data_t old_tail;
	size_t size;
	size_t data_len = 0;
	struct sk_buff *skb;
	struct nfqnl_msg_packet_hdr pmsg;
	struct nlmsghdr *nlh;
	struct nfgenmsg *nfmsg;
	struct sk_buff *entskb = entry->skb;
	struct net_device *indev;
	struct net_device *outdev;

	size =    NLMSG_SPACE(sizeof(struct nfgenmsg))
		+ nla_total_size(sizeof(struct nfqnl_msg_packet_hdr))
		+ nla_total_size(sizeof(u_int32_t))	/* ifindex */
		+ nla_total_size(sizeof(u_int32_t))	/* ifindex */
#ifdef CONFIG_BRIDGE_NETFILTER
		+ nla_total_size(sizeof(u_int32_t))	/* ifindex */
		+ nla_total_size(sizeof(u_int32_t))	/* ifindex */
#endif
		+ nla_total_size(sizeof(u_int32_t))	/* mark */
		+ nla_total_size(sizeof(struct nfqnl_msg_packet_hw))
		+ nla_total_size(sizeof(struct nfqnl_msg_packet_timestamp));

	outdev = entry->outdev;

	switch ((enum nfqnl_config_mode)ACCESS_ONCE(queue->copy_mode)) {
	case NFQNL_COPY_META:
	case NFQNL_COPY_NONE:
		break;

	case NFQNL_COPY_PACKET:
		if (entskb->ip_summed == CHECKSUM_PARTIAL &&
		    skb_checksum_help(entskb))
			return NULL;

		data_len = ACCESS_ONCE(queue->copy_range);
		if (data_len == 0 || data_len > entskb->len)
			data_len = entskb->len;

		size += nla_total_size(data_len);
		break;
	}


	skb = alloc_skb(size, GFP_ATOMIC);
	if (!skb)
		goto nlmsg_failure;

	old_tail = skb->tail;
	nlh = NLMSG_PUT(skb, 0, 0,
			NFNL_SUBSYS_QUEUE << 8 | NFQNL_MSG_PACKET,
			sizeof(struct nfgenmsg));
	nfmsg = NLMSG_DATA(nlh);
	nfmsg->nfgen_family = entry->pf;
	nfmsg->version = NFNETLINK_V0;
	nfmsg->res_id = htons(queue->queue_num);

	entry->id = atomic_inc_return(&queue->id_sequence);
	pmsg.packet_id 		= htonl(entry->id);
	pmsg.hw_protocol	= entskb->protocol;
	pmsg.hook		= entry->hook;

	NLA_PUT(skb, NFQA_PACKET_HDR, sizeof(pmsg), &pmsg);

	indev = entry->indev;
	if (indev) {
#ifndef CONFIG_BRIDGE_NETFILTER
		NLA_PUT_BE32(skb, NFQA_IFINDEX_INDEV, htonl(indev->ifindex));
#else
		if (entry->pf == PF_BRIDGE) {
			/* Case 1: indev is physical input device, we need to
			 * look for bridge group (when called from
			 * netfilter_bridge) */
			NLA_PUT_BE32(skb, NFQA_IFINDEX_PHYSINDEV,
				     htonl(indev->ifindex));
			/* this is the bridge group "brX" */
			/* rcu_read_lock()ed by __nf_queue */
			NLA_PUT_BE32(skb, NFQA_IFINDEX_INDEV,
				     htonl(br_port_get_rcu(indev)->br->dev->ifindex));
		} else {
			/* Case 2: indev is bridge group, we need to look for
			 * physical device (when called from ipv4) */
			NLA_PUT_BE32(skb, NFQA_IFINDEX_INDEV,
				     htonl(indev->ifindex));
			if (entskb->nf_bridge && entskb->nf_bridge->physindev)
				NLA_PUT_BE32(skb, NFQA_IFINDEX_PHYSINDEV,
					     htonl(entskb->nf_bridge->physindev->ifindex));
		}
#endif
	}

	if (outdev) {
#ifndef CONFIG_BRIDGE_NETFILTER
		NLA_PUT_BE32(skb, NFQA_IFINDEX_OUTDEV, htonl(outdev->ifindex));
#else
		if (entry->pf == PF_BRIDGE) {
			/* Case 1: outdev is physical output device, we need to
			 * look for bridge group (when called from
			 * netfilter_bridge) */
			NLA_PUT_BE32(skb, NFQA_IFINDEX_PHYSOUTDEV,
				     htonl(outdev->ifindex));
			/* this is the bridge group "brX" */
			/* rcu_read_lock()ed by __nf_queue */
			NLA_PUT_BE32(skb, NFQA_IFINDEX_OUTDEV,
				     htonl(br_port_get_rcu(outdev)->br->dev->ifindex));
		} else {
			/* Case 2: outdev is bridge group, we need to look for
			 * physical output device (when called from ipv4) */
			NLA_PUT_BE32(skb, NFQA_IFINDEX_OUTDEV,
				     htonl(outdev->ifindex));
			if (entskb->nf_bridge && entskb->nf_bridge->physoutdev)
				NLA_PUT_BE32(skb, NFQA_IFINDEX_PHYSOUTDEV,
					     htonl(entskb->nf_bridge->physoutdev->ifindex));
		}
#endif
	}

	if (entskb->mark)
		NLA_PUT_BE32(skb, NFQA_MARK, htonl(entskb->mark));

	if (indev && entskb->dev) {
		struct nfqnl_msg_packet_hw phw;
		int len = dev_parse_header(entskb, phw.hw_addr);
		if (len) {
			phw.hw_addrlen = htons(len);
			NLA_PUT(skb, NFQA_HWADDR, sizeof(phw), &phw);
		}
	}

	if (entskb->tstamp.tv64) {
		struct nfqnl_msg_packet_timestamp ts;
		struct timeval tv = ktime_to_timeval(entskb->tstamp);
		ts.sec = cpu_to_be64(tv.tv_sec);
		ts.usec = cpu_to_be64(tv.tv_usec);

		NLA_PUT(skb, NFQA_TIMESTAMP, sizeof(ts), &ts);
	}

	if (data_len) {
		struct nlattr *nla;
		int sz = nla_attr_size(data_len);

		if (skb_tailroom(skb) < nla_total_size(data_len)) {
			printk(KERN_WARNING "nf_queue: no tailroom!\n");
			goto nlmsg_failure;
		}

		nla = (struct nlattr *)skb_put(skb, nla_total_size(data_len));
		nla->nla_type = NFQA_PAYLOAD;
		nla->nla_len = sz;

		if (skb_copy_bits(entskb, 0, nla_data(nla), data_len))
			BUG();
	}

	nlh->nlmsg_len = skb->tail - old_tail;
	return skb;

nlmsg_failure:
nla_put_failure:
	if (skb)
		kfree_skb(skb);
	if (net_ratelimit())
		printk(KERN_ERR "nf_queue: error creating packet message\n");
	return NULL;
}

static int
nfqnl_enqueue_packet(struct nf_queue_entry *entry, unsigned int queuenum)
{
	struct sk_buff *nskb;
	struct nfqnl_instance *queue;
	int err;

	/* rcu_read_lock()ed by nf_hook_slow() */
	queue = instance_lookup(queuenum);
	if (!queue)
		goto err_out;

	if (queue->copy_mode == NFQNL_COPY_NONE)
		goto err_out;

	nskb = nfqnl_build_packet_message(queue, entry);
	if (nskb == NULL)
		goto err_out;

	spin_lock_bh(&queue->lock);

	if (!queue->peer_pid)
		goto err_out_free_nskb;

	if (queue->queue_total >= queue->queue_maxlen) {
		queue->queue_dropped++;
		if (net_ratelimit())
			  printk(KERN_WARNING "nf_queue: full at %d entries, "
				 "dropping packets(s).\n",
				 queue->queue_total);
		goto err_out_free_nskb;
	}

	/* nfnetlink_unicast will either free the nskb or add it to a socket */
	err = nfnetlink_unicast(nskb, &init_net, queue->peer_pid, MSG_DONTWAIT);
	if (err < 0) {
		queue->queue_user_dropped++;
		goto err_out_unlock;
	}

	__enqueue_entry(queue, entry);

	spin_unlock_bh(&queue->lock);
	return 0;

err_out_free_nskb:
	kfree_skb(nskb);
err_out_unlock:
	spin_unlock_bh(&queue->lock);
err_out:
	return -1;
}

static int
nfqnl_mangle(void *data, int data_len, struct nf_queue_entry *e)
{
	struct sk_buff *nskb;
	int diff;

	diff = data_len - e->skb->len;
	if (diff < 0) {
		if (pskb_trim(e->skb, data_len))
			return -ENOMEM;
	} else if (diff > 0) {
		if (data_len > 0xFFFF)
			return -EINVAL;
		if (diff > skb_tailroom(e->skb)) {
			nskb = skb_copy_expand(e->skb, skb_headroom(e->skb),
					       diff, GFP_ATOMIC);
			if (!nskb) {
				printk(KERN_WARNING "nf_queue: OOM "
				      "in mangle, dropping packet\n");
				return -ENOMEM;
			}
			kfree_skb(e->skb);
			e->skb = nskb;
		}
		skb_put(e->skb, diff);
	}
	if (!skb_make_writable(e->skb, data_len))
		return -ENOMEM;
	skb_copy_to_linear_data(e->skb, data, data_len);
	e->skb->ip_summed = CHECKSUM_NONE;
	return 0;
}

static int
nfqnl_set_mode(struct nfqnl_instance *queue,
	       unsigned char mode, unsigned int range)
{
	int status = 0;

	spin_lock_bh(&queue->lock);
	switch (mode) {
	case NFQNL_COPY_NONE:
	case NFQNL_COPY_META:
		queue->copy_mode = mode;
		queue->copy_range = 0;
		break;

	case NFQNL_COPY_PACKET:
		queue->copy_mode = mode;
		/* we're using struct nlattr which has 16bit nla_len */
		if (range > 0xffff)
			queue->copy_range = 0xffff;
		else
			queue->copy_range = range;
		break;

	default:
		status = -EINVAL;

	}
	spin_unlock_bh(&queue->lock);

	return status;
}

static int
dev_cmp(struct nf_queue_entry *entry, unsigned long ifindex)
{
	if (entry->indev)
		if (entry->indev->ifindex == ifindex)
			return 1;
	if (entry->outdev)
		if (entry->outdev->ifindex == ifindex)
			return 1;
#ifdef CONFIG_BRIDGE_NETFILTER
	if (entry->skb->nf_bridge) {
		if (entry->skb->nf_bridge->physindev &&
		    entry->skb->nf_bridge->physindev->ifindex == ifindex)
			return 1;
		if (entry->skb->nf_bridge->physoutdev &&
		    entry->skb->nf_bridge->physoutdev->ifindex == ifindex)
			return 1;
	}
#endif
	return 0;
}

/* drop all packets with either indev or outdev == ifindex from all queue
 * instances */
static void
nfqnl_dev_drop(int ifindex)
{
	int i;

	rcu_read_lock();

	for (i = 0; i < INSTANCE_BUCKETS; i++) {
		struct hlist_node *tmp;
		struct nfqnl_instance *inst;
		struct hlist_head *head = &instance_table[i];

		hlist_for_each_entry_rcu(inst, tmp, head, hlist)
			nfqnl_flush(inst, dev_cmp, ifindex);
	}

	rcu_read_unlock();
}

#define RCV_SKB_FAIL(err) do { netlink_ack(skb, nlh, (err)); return; } while (0)

static int
nfqnl_rcv_dev_event(struct notifier_block *this,
		    unsigned long event, void *ptr)
{
	struct net_device *dev = ptr;

	if (!net_eq(dev_net(dev), &init_net))
		return NOTIFY_DONE;

	/* Drop any packets associated with the downed device */
	if (event == NETDEV_DOWN)
		nfqnl_dev_drop(dev->ifindex);
	return NOTIFY_DONE;
}

static struct notifier_block nfqnl_dev_notifier = {
	.notifier_call	= nfqnl_rcv_dev_event,
};

static int
nfqnl_rcv_nl_event(struct notifier_block *this,
		   unsigned long event, void *ptr)
{
	struct netlink_notify *n = ptr;

	if (event == NETLINK_URELEASE && n->protocol == NETLINK_NETFILTER) {
		int i;

		/* destroy all instances for this pid */
		spin_lock(&instances_lock);
		for (i = 0; i < INSTANCE_BUCKETS; i++) {
			struct hlist_node *tmp, *t2;
			struct nfqnl_instance *inst;
			struct hlist_head *head = &instance_table[i];

			hlist_for_each_entry_safe(inst, tmp, t2, head, hlist) {
				if ((n->net == &init_net) &&
				    (n->pid == inst->peer_pid))
					__instance_destroy(inst);
			}
		}
		spin_unlock(&instances_lock);
	}
	return NOTIFY_DONE;
}

static struct notifier_block nfqnl_rtnl_notifier = {
	.notifier_call	= nfqnl_rcv_nl_event,
};

static const struct nla_policy nfqa_verdict_policy[NFQA_MAX+1] = {
	[NFQA_VERDICT_HDR]	= { .len = sizeof(struct nfqnl_msg_verdict_hdr) },
	[NFQA_MARK]		= { .type = NLA_U32 },
	[NFQA_PAYLOAD]		= { .type = NLA_UNSPEC },
};

static int
nfqnl_recv_verdict(struct sock *ctnl, struct sk_buff *skb,
		   const struct nlmsghdr *nlh,
		   const struct nlattr * const nfqa[])
{
	struct nfgenmsg *nfmsg = NLMSG_DATA(nlh);
	u_int16_t queue_num = ntohs(nfmsg->res_id);

	struct nfqnl_msg_verdict_hdr *vhdr;
	struct nfqnl_instance *queue;
	unsigned int verdict;
	struct nf_queue_entry *entry;
	int err;

	rcu_read_lock();
	queue = instance_lookup(queue_num);
	if (!queue) {
		err = -ENODEV;
		goto err_out_unlock;
	}

	if (queue->peer_pid != NETLINK_CB(skb).pid) {
		err = -EPERM;
		goto err_out_unlock;
	}

	if (!nfqa[NFQA_VERDICT_HDR]) {
		err = -EINVAL;
		goto err_out_unlock;
	}

	vhdr = nla_data(nfqa[NFQA_VERDICT_HDR]);
	verdict = ntohl(vhdr->verdict);

	if ((verdict & NF_VERDICT_MASK) > NF_MAX_VERDICT) {
		err = -EINVAL;
		goto err_out_unlock;
	}

	entry = find_dequeue_entry(queue, ntohl(vhdr->id));
	if (entry == NULL) {
		err = -ENOENT;
		goto err_out_unlock;
	}
	rcu_read_unlock();

	if (nfqa[NFQA_PAYLOAD]) {
		if (nfqnl_mangle(nla_data(nfqa[NFQA_PAYLOAD]),
				 nla_len(nfqa[NFQA_PAYLOAD]), entry) < 0)
			verdict = NF_DROP;
	}

	if (nfqa[NFQA_MARK])
		entry->skb->mark = ntohl(nla_get_be32(nfqa[NFQA_MARK]));

	nf_reinject(entry, verdict);
	return 0;

err_out_unlock:
	rcu_read_unlock();
	return err;
}

static int
nfqnl_recv_unsupp(struct sock *ctnl, struct sk_buff *skb,
		  const struct nlmsghdr *nlh,
		  const struct nlattr * const nfqa[])
{
	return -ENOTSUPP;
}

static const struct nla_policy nfqa_cfg_policy[NFQA_CFG_MAX+1] = {
	[NFQA_CFG_CMD]		= { .len = sizeof(struct nfqnl_msg_config_cmd) },
	[NFQA_CFG_PARAMS]	= { .len = sizeof(struct nfqnl_msg_config_params) },
};

static const struct nf_queue_handler nfqh = {
	.name 	= "nf_queue",
	.outfn	= &nfqnl_enqueue_packet,
};

static int
nfqnl_recv_config(struct sock *ctnl, struct sk_buff *skb,
		  const struct nlmsghdr *nlh,
		  const struct nlattr * const nfqa[])
{
	struct nfgenmsg *nfmsg = NLMSG_DATA(nlh);
	u_int16_t queue_num = ntohs(nfmsg->res_id);
	struct nfqnl_instance *queue;
	struct nfqnl_msg_config_cmd *cmd = NULL;
	int ret = 0;

	if (nfqa[NFQA_CFG_CMD]) {
		cmd = nla_data(nfqa[NFQA_CFG_CMD]);

		/* Commands without queue context - might sleep */
		switch (cmd->command) {
		case NFQNL_CFG_CMD_PF_BIND:
			return nf_register_queue_handler(ntohs(cmd->pf),
							 &nfqh);
		case NFQNL_CFG_CMD_PF_UNBIND:
			return nf_unregister_queue_handler(ntohs(cmd->pf),
							   &nfqh);
		}
	}

	rcu_read_lock();
	queue = instance_lookup(queue_num);
	if (queue && queue->peer_pid != NETLINK_CB(skb).pid) {
		ret = -EPERM;
		goto err_out_unlock;
	}

	if (cmd != NULL) {
		switch (cmd->command) {
		case NFQNL_CFG_CMD_BIND:
			if (queue) {
				ret = -EBUSY;
				goto err_out_unlock;
			}
			queue = instance_create(queue_num, NETLINK_CB(skb).pid);
			if (IS_ERR(queue)) {
				ret = PTR_ERR(queue);
				goto err_out_unlock;
			}
			break;
		case NFQNL_CFG_CMD_UNBIND:
			if (!queue) {
				ret = -ENODEV;
				goto err_out_unlock;
			}
			instance_destroy(queue);
			break;
		case NFQNL_CFG_CMD_PF_BIND:
		case NFQNL_CFG_CMD_PF_UNBIND:
			break;
		default:
			ret = -ENOTSUPP;
			break;
		}
	}

	if (nfqa[NFQA_CFG_PARAMS]) {
		struct nfqnl_msg_config_params *params;

		if (!queue) {
			ret = -ENODEV;
			goto err_out_unlock;
		}
		params = nla_data(nfqa[NFQA_CFG_PARAMS]);
		nfqnl_set_mode(queue, params->copy_mode,
				ntohl(params->copy_range));
	}

	if (nfqa[NFQA_CFG_QUEUE_MAXLEN]) {
		__be32 *queue_maxlen;

		if (!queue) {
			ret = -ENODEV;
			goto err_out_unlock;
		}
		queue_maxlen = nla_data(nfqa[NFQA_CFG_QUEUE_MAXLEN]);
		spin_lock_bh(&queue->lock);
		queue->queue_maxlen = ntohl(*queue_maxlen);
		spin_unlock_bh(&queue->lock);
	}

err_out_unlock:
	rcu_read_unlock();
	return ret;
}

static const struct nfnl_callback nfqnl_cb[NFQNL_MSG_MAX] = {
	[NFQNL_MSG_PACKET]	= { .call = nfqnl_recv_unsupp,
				    .attr_count = NFQA_MAX, },
	[NFQNL_MSG_VERDICT]	= { .call = nfqnl_recv_verdict,
				    .attr_count = NFQA_MAX,
				    .policy = nfqa_verdict_policy },
	[NFQNL_MSG_CONFIG]	= { .call = nfqnl_recv_config,
				    .attr_count = NFQA_CFG_MAX,
				    .policy = nfqa_cfg_policy },
};

static const struct nfnetlink_subsystem nfqnl_subsys = {
	.name		= "nf_queue",
	.subsys_id	= NFNL_SUBSYS_QUEUE,
	.cb_count	= NFQNL_MSG_MAX,
	.cb		= nfqnl_cb,
};

#ifdef CONFIG_PROC_FS
struct iter_state {
	unsigned int bucket;
};

static struct hlist_node *get_first(struct seq_file *seq)
{
	struct iter_state *st = seq->private;

	if (!st)
		return NULL;

	for (st->bucket = 0; st->bucket < INSTANCE_BUCKETS; st->bucket++) {
		if (!hlist_empty(&instance_table[st->bucket]))
			return instance_table[st->bucket].first;
	}
	return NULL;
}

static struct hlist_node *get_next(struct seq_file *seq, struct hlist_node *h)
{
	struct iter_state *st = seq->private;

	h = h->next;
	while (!h) {
		if (++st->bucket >= INSTANCE_BUCKETS)
			return NULL;

		h = instance_table[st->bucket].first;
	}
	return h;
}

static struct hlist_node *get_idx(struct seq_file *seq, loff_t pos)
{
	struct hlist_node *head;
	head = get_first(seq);

	if (head)
		while (pos && (head = get_next(seq, head)))
			pos--;
	return pos ? NULL : head;
}

static void *seq_start(struct seq_file *seq, loff_t *pos)
	__acquires(instances_lock)
{
	spin_lock(&instances_lock);
	return get_idx(seq, *pos);
}

static void *seq_next(struct seq_file *s, void *v, loff_t *pos)
{
	(*pos)++;
	return get_next(s, v);
}

static void seq_stop(struct seq_file *s, void *v)
	__releases(instances_lock)
{
	spin_unlock(&instances_lock);
}

static int seq_show(struct seq_file *s, void *v)
{
	const struct nfqnl_instance *inst = v;

	return seq_printf(s, "%5d %6d %5d %1d %5d %5d %5d %8d %2d\n",
			  inst->queue_num,
			  inst->peer_pid, inst->queue_total,
			  inst->copy_mode, inst->copy_range,
			  inst->queue_dropped, inst->queue_user_dropped,
			  atomic_read(&inst->id_sequence), 1);
}

static const struct seq_operations nfqnl_seq_ops = {
	.start	= seq_start,
	.next	= seq_next,
	.stop	= seq_stop,
	.show	= seq_show,
};

static int nfqnl_open(struct inode *inode, struct file *file)
{
	return seq_open_private(file, &nfqnl_seq_ops,
			sizeof(struct iter_state));
}

static const struct file_operations nfqnl_file_ops = {
	.owner	 = THIS_MODULE,
	.open	 = nfqnl_open,
	.read	 = seq_read,
	.llseek	 = seq_lseek,
	.release = seq_release_private,
};

#endif /* PROC_FS */

static int __init nfnetlink_queue_init(void)
{
	int i, status = -ENOMEM;

	for (i = 0; i < INSTANCE_BUCKETS; i++)
		INIT_HLIST_HEAD(&instance_table[i]);

	netlink_register_notifier(&nfqnl_rtnl_notifier);
	status = nfnetlink_subsys_register(&nfqnl_subsys);
	if (status < 0) {
		printk(KERN_ERR "nf_queue: failed to create netlink socket\n");
		goto cleanup_netlink_notifier;
	}

#ifdef CONFIG_PROC_FS
	if (!proc_create("nfnetlink_queue", 0440,
			 proc_net_netfilter, &nfqnl_file_ops))
		goto cleanup_subsys;
#endif

	register_netdevice_notifier(&nfqnl_dev_notifier);
	return status;

#ifdef CONFIG_PROC_FS
cleanup_subsys:
	nfnetlink_subsys_unregister(&nfqnl_subsys);
#endif
cleanup_netlink_notifier:
	netlink_unregister_notifier(&nfqnl_rtnl_notifier);
	return status;
}

static void __exit nfnetlink_queue_fini(void)
{
	nf_unregister_queue_handlers(&nfqh);
	unregister_netdevice_notifier(&nfqnl_dev_notifier);
#ifdef CONFIG_PROC_FS
	remove_proc_entry("nfnetlink_queue", proc_net_netfilter);
#endif
	nfnetlink_subsys_unregister(&nfqnl_subsys);
	netlink_unregister_notifier(&nfqnl_rtnl_notifier);

	rcu_barrier(); /* Wait for completion of call_rcu()'s */
}

MODULE_DESCRIPTION("netfilter packet queue handler");
MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
MODULE_LICENSE("GPL");
MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_QUEUE);

module_init(nfnetlink_queue_init);
module_exit(nfnetlink_queue_fini);