Free Electrons

Embedded Linux Experts

  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
/*
 * IPv6 fragment reassembly for connection tracking
 *
 * Copyright (C)2004 USAGI/WIDE Project
 *
 * Author:
 *	Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp>
 *
 * Based on: net/ipv6/reassembly.c
 *
 * 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.
 */

#define pr_fmt(fmt) "IPv6-nf: " fmt

#include <linux/errno.h>
#include <linux/types.h>
#include <linux/string.h>
#include <linux/socket.h>
#include <linux/sockios.h>
#include <linux/jiffies.h>
#include <linux/net.h>
#include <linux/list.h>
#include <linux/netdevice.h>
#include <linux/in6.h>
#include <linux/ipv6.h>
#include <linux/icmpv6.h>
#include <linux/random.h>
#include <linux/slab.h>

#include <net/sock.h>
#include <net/snmp.h>
#include <net/inet_frag.h>

#include <net/ipv6.h>
#include <net/protocol.h>
#include <net/transp_v6.h>
#include <net/rawv6.h>
#include <net/ndisc.h>
#include <net/addrconf.h>
#include <net/inet_ecn.h>
#include <net/netfilter/ipv6/nf_conntrack_ipv6.h>
#include <linux/sysctl.h>
#include <linux/netfilter.h>
#include <linux/netfilter_ipv6.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <net/netfilter/ipv6/nf_defrag_ipv6.h>

static const char nf_frags_cache_name[] = "nf-frags";

struct nf_ct_frag6_skb_cb
{
	struct inet6_skb_parm	h;
	int			offset;
	struct sk_buff		*orig;
};

#define NFCT_FRAG6_CB(skb)	((struct nf_ct_frag6_skb_cb*)((skb)->cb))

static struct inet_frags nf_frags;

#ifdef CONFIG_SYSCTL
static int zero;

static struct ctl_table nf_ct_frag6_sysctl_table[] = {
	{
		.procname	= "nf_conntrack_frag6_timeout",
		.data		= &init_net.nf_frag.frags.timeout,
		.maxlen		= sizeof(unsigned int),
		.mode		= 0644,
		.proc_handler	= proc_dointvec_jiffies,
	},
	{
		.procname	= "nf_conntrack_frag6_low_thresh",
		.data		= &init_net.nf_frag.frags.low_thresh,
		.maxlen		= sizeof(unsigned int),
		.mode		= 0644,
		.proc_handler	= proc_dointvec_minmax,
		.extra1		= &zero,
		.extra2		= &init_net.nf_frag.frags.high_thresh
	},
	{
		.procname	= "nf_conntrack_frag6_high_thresh",
		.data		= &init_net.nf_frag.frags.high_thresh,
		.maxlen		= sizeof(unsigned int),
		.mode		= 0644,
		.proc_handler	= proc_dointvec_minmax,
		.extra1		= &init_net.nf_frag.frags.low_thresh
	},
	{ }
};

static int nf_ct_frag6_sysctl_register(struct net *net)
{
	struct ctl_table *table;
	struct ctl_table_header *hdr;

	table = nf_ct_frag6_sysctl_table;
	if (!net_eq(net, &init_net)) {
		table = kmemdup(table, sizeof(nf_ct_frag6_sysctl_table),
				GFP_KERNEL);
		if (table == NULL)
			goto err_alloc;

		table[0].data = &net->nf_frag.frags.timeout;
		table[1].data = &net->nf_frag.frags.low_thresh;
		table[1].extra2 = &net->nf_frag.frags.high_thresh;
		table[2].data = &net->nf_frag.frags.high_thresh;
		table[2].extra1 = &net->nf_frag.frags.low_thresh;
		table[2].extra2 = &init_net.nf_frag.frags.high_thresh;
	}

	hdr = register_net_sysctl(net, "net/netfilter", table);
	if (hdr == NULL)
		goto err_reg;

	net->nf_frag.sysctl.frags_hdr = hdr;
	return 0;

err_reg:
	if (!net_eq(net, &init_net))
		kfree(table);
err_alloc:
	return -ENOMEM;
}

static void __net_exit nf_ct_frags6_sysctl_unregister(struct net *net)
{
	struct ctl_table *table;

	table = net->nf_frag.sysctl.frags_hdr->ctl_table_arg;
	unregister_net_sysctl_table(net->nf_frag.sysctl.frags_hdr);
	if (!net_eq(net, &init_net))
		kfree(table);
}

#else
static int nf_ct_frag6_sysctl_register(struct net *net)
{
	return 0;
}
static void __net_exit nf_ct_frags6_sysctl_unregister(struct net *net)
{
}
#endif

static inline u8 ip6_frag_ecn(const struct ipv6hdr *ipv6h)
{
	return 1 << (ipv6_get_dsfield(ipv6h) & INET_ECN_MASK);
}

static unsigned int nf_hash_frag(__be32 id, const struct in6_addr *saddr,
				 const struct in6_addr *daddr)
{
	net_get_random_once(&nf_frags.rnd, sizeof(nf_frags.rnd));
	return jhash_3words(ipv6_addr_hash(saddr), ipv6_addr_hash(daddr),
			    (__force u32)id, nf_frags.rnd);
}


static unsigned int nf_hashfn(const struct inet_frag_queue *q)
{
	const struct frag_queue *nq;

	nq = container_of(q, struct frag_queue, q);
	return nf_hash_frag(nq->id, &nq->saddr, &nq->daddr);
}

static void nf_skb_free(struct sk_buff *skb)
{
	if (NFCT_FRAG6_CB(skb)->orig)
		kfree_skb(NFCT_FRAG6_CB(skb)->orig);
}

static void nf_ct_frag6_expire(unsigned long data)
{
	struct frag_queue *fq;
	struct net *net;

	fq = container_of((struct inet_frag_queue *)data, struct frag_queue, q);
	net = container_of(fq->q.net, struct net, nf_frag.frags);

	ip6_expire_frag_queue(net, fq, &nf_frags);
}

/* Creation primitives. */
static inline struct frag_queue *fq_find(struct net *net, __be32 id,
					 u32 user, struct in6_addr *src,
					 struct in6_addr *dst, int iif, u8 ecn)
{
	struct inet_frag_queue *q;
	struct ip6_create_arg arg;
	unsigned int hash;

	arg.id = id;
	arg.user = user;
	arg.src = src;
	arg.dst = dst;
	arg.iif = iif;
	arg.ecn = ecn;

	local_bh_disable();
	hash = nf_hash_frag(id, src, dst);

	q = inet_frag_find(&net->nf_frag.frags, &nf_frags, &arg, hash);
	local_bh_enable();
	if (IS_ERR_OR_NULL(q)) {
		inet_frag_maybe_warn_overflow(q, pr_fmt());
		return NULL;
	}
	return container_of(q, struct frag_queue, q);
}


static int nf_ct_frag6_queue(struct frag_queue *fq, struct sk_buff *skb,
			     const struct frag_hdr *fhdr, int nhoff)
{
	struct sk_buff *prev, *next;
	unsigned int payload_len;
	int offset, end;
	u8 ecn;

	if (fq->q.flags & INET_FRAG_COMPLETE) {
		pr_debug("Already completed\n");
		goto err;
	}

	payload_len = ntohs(ipv6_hdr(skb)->payload_len);

	offset = ntohs(fhdr->frag_off) & ~0x7;
	end = offset + (payload_len -
			((u8 *)(fhdr + 1) - (u8 *)(ipv6_hdr(skb) + 1)));

	if ((unsigned int)end > IPV6_MAXPLEN) {
		pr_debug("offset is too large.\n");
		return -1;
	}

	ecn = ip6_frag_ecn(ipv6_hdr(skb));

	if (skb->ip_summed == CHECKSUM_COMPLETE) {
		const unsigned char *nh = skb_network_header(skb);
		skb->csum = csum_sub(skb->csum,
				     csum_partial(nh, (u8 *)(fhdr + 1) - nh,
						  0));
	}

	/* Is this the final fragment? */
	if (!(fhdr->frag_off & htons(IP6_MF))) {
		/* If we already have some bits beyond end
		 * or have different end, the segment is corrupted.
		 */
		if (end < fq->q.len ||
		    ((fq->q.flags & INET_FRAG_LAST_IN) && end != fq->q.len)) {
			pr_debug("already received last fragment\n");
			goto err;
		}
		fq->q.flags |= INET_FRAG_LAST_IN;
		fq->q.len = end;
	} else {
		/* Check if the fragment is rounded to 8 bytes.
		 * Required by the RFC.
		 */
		if (end & 0x7) {
			/* RFC2460 says always send parameter problem in
			 * this case. -DaveM
			 */
			pr_debug("end of fragment not rounded to 8 bytes.\n");
			return -1;
		}
		if (end > fq->q.len) {
			/* Some bits beyond end -> corruption. */
			if (fq->q.flags & INET_FRAG_LAST_IN) {
				pr_debug("last packet already reached.\n");
				goto err;
			}
			fq->q.len = end;
		}
	}

	if (end == offset)
		goto err;

	/* Point into the IP datagram 'data' part. */
	if (!pskb_pull(skb, (u8 *) (fhdr + 1) - skb->data)) {
		pr_debug("queue: message is too short.\n");
		goto err;
	}
	if (pskb_trim_rcsum(skb, end - offset)) {
		pr_debug("Can't trim\n");
		goto err;
	}

	/* Find out which fragments are in front and at the back of us
	 * in the chain of fragments so far.  We must know where to put
	 * this fragment, right?
	 */
	prev = fq->q.fragments_tail;
	if (!prev || NFCT_FRAG6_CB(prev)->offset < offset) {
		next = NULL;
		goto found;
	}
	prev = NULL;
	for (next = fq->q.fragments; next != NULL; next = next->next) {
		if (NFCT_FRAG6_CB(next)->offset >= offset)
			break;	/* bingo! */
		prev = next;
	}

found:
	/* RFC5722, Section 4:
	 *                                  When reassembling an IPv6 datagram, if
	 *   one or more its constituent fragments is determined to be an
	 *   overlapping fragment, the entire datagram (and any constituent
	 *   fragments, including those not yet received) MUST be silently
	 *   discarded.
	 */

	/* Check for overlap with preceding fragment. */
	if (prev &&
	    (NFCT_FRAG6_CB(prev)->offset + prev->len) > offset)
		goto discard_fq;

	/* Look for overlap with succeeding segment. */
	if (next && NFCT_FRAG6_CB(next)->offset < end)
		goto discard_fq;

	NFCT_FRAG6_CB(skb)->offset = offset;

	/* Insert this fragment in the chain of fragments. */
	skb->next = next;
	if (!next)
		fq->q.fragments_tail = skb;
	if (prev)
		prev->next = skb;
	else
		fq->q.fragments = skb;

	if (skb->dev) {
		fq->iif = skb->dev->ifindex;
		skb->dev = NULL;
	}
	fq->q.stamp = skb->tstamp;
	fq->q.meat += skb->len;
	fq->ecn |= ecn;
	if (payload_len > fq->q.max_size)
		fq->q.max_size = payload_len;
	add_frag_mem_limit(&fq->q, skb->truesize);

	/* The first fragment.
	 * nhoffset is obtained from the first fragment, of course.
	 */
	if (offset == 0) {
		fq->nhoffset = nhoff;
		fq->q.flags |= INET_FRAG_FIRST_IN;
	}

	return 0;

discard_fq:
	inet_frag_kill(&fq->q, &nf_frags);
err:
	return -1;
}

/*
 *	Check if this packet is complete.
 *	Returns NULL on failure by any reason, and pointer
 *	to current nexthdr field in reassembled frame.
 *
 *	It is called with locked fq, and caller must check that
 *	queue is eligible for reassembly i.e. it is not COMPLETE,
 *	the last and the first frames arrived and all the bits are here.
 */
static struct sk_buff *
nf_ct_frag6_reasm(struct frag_queue *fq, struct net_device *dev)
{
	struct sk_buff *fp, *op, *head = fq->q.fragments;
	int    payload_len;
	u8 ecn;

	inet_frag_kill(&fq->q, &nf_frags);

	WARN_ON(head == NULL);
	WARN_ON(NFCT_FRAG6_CB(head)->offset != 0);

	ecn = ip_frag_ecn_table[fq->ecn];
	if (unlikely(ecn == 0xff))
		goto out_fail;

	/* Unfragmented part is taken from the first segment. */
	payload_len = ((head->data - skb_network_header(head)) -
		       sizeof(struct ipv6hdr) + fq->q.len -
		       sizeof(struct frag_hdr));
	if (payload_len > IPV6_MAXPLEN) {
		pr_debug("payload len is too large.\n");
		goto out_oversize;
	}

	/* Head of list must not be cloned. */
	if (skb_unclone(head, GFP_ATOMIC)) {
		pr_debug("skb is cloned but can't expand head");
		goto out_oom;
	}

	/* If the first fragment is fragmented itself, we split
	 * it to two chunks: the first with data and paged part
	 * and the second, holding only fragments. */
	if (skb_has_frag_list(head)) {
		struct sk_buff *clone;
		int i, plen = 0;

		clone = alloc_skb(0, GFP_ATOMIC);
		if (clone == NULL)
			goto out_oom;

		clone->next = head->next;
		head->next = clone;
		skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list;
		skb_frag_list_init(head);
		for (i = 0; i < skb_shinfo(head)->nr_frags; i++)
			plen += skb_frag_size(&skb_shinfo(head)->frags[i]);
		clone->len = clone->data_len = head->data_len - plen;
		head->data_len -= clone->len;
		head->len -= clone->len;
		clone->csum = 0;
		clone->ip_summed = head->ip_summed;

		NFCT_FRAG6_CB(clone)->orig = NULL;
		add_frag_mem_limit(&fq->q, clone->truesize);
	}

	/* We have to remove fragment header from datagram and to relocate
	 * header in order to calculate ICV correctly. */
	skb_network_header(head)[fq->nhoffset] = skb_transport_header(head)[0];
	memmove(head->head + sizeof(struct frag_hdr), head->head,
		(head->data - head->head) - sizeof(struct frag_hdr));
	head->mac_header += sizeof(struct frag_hdr);
	head->network_header += sizeof(struct frag_hdr);

	skb_shinfo(head)->frag_list = head->next;
	skb_reset_transport_header(head);
	skb_push(head, head->data - skb_network_header(head));

	for (fp=head->next; fp; fp = fp->next) {
		head->data_len += fp->len;
		head->len += fp->len;
		if (head->ip_summed != fp->ip_summed)
			head->ip_summed = CHECKSUM_NONE;
		else if (head->ip_summed == CHECKSUM_COMPLETE)
			head->csum = csum_add(head->csum, fp->csum);
		head->truesize += fp->truesize;
	}
	sub_frag_mem_limit(&fq->q, head->truesize);

	head->ignore_df = 1;
	head->next = NULL;
	head->dev = dev;
	head->tstamp = fq->q.stamp;
	ipv6_hdr(head)->payload_len = htons(payload_len);
	ipv6_change_dsfield(ipv6_hdr(head), 0xff, ecn);
	IP6CB(head)->frag_max_size = sizeof(struct ipv6hdr) + fq->q.max_size;

	/* Yes, and fold redundant checksum back. 8) */
	if (head->ip_summed == CHECKSUM_COMPLETE)
		head->csum = csum_partial(skb_network_header(head),
					  skb_network_header_len(head),
					  head->csum);

	fq->q.fragments = NULL;
	fq->q.fragments_tail = NULL;

	/* all original skbs are linked into the NFCT_FRAG6_CB(head).orig */
	fp = skb_shinfo(head)->frag_list;
	if (fp && NFCT_FRAG6_CB(fp)->orig == NULL)
		/* at above code, head skb is divided into two skbs. */
		fp = fp->next;

	op = NFCT_FRAG6_CB(head)->orig;
	for (; fp; fp = fp->next) {
		struct sk_buff *orig = NFCT_FRAG6_CB(fp)->orig;

		op->next = orig;
		op = orig;
		NFCT_FRAG6_CB(fp)->orig = NULL;
	}

	return head;

out_oversize:
	net_dbg_ratelimited("nf_ct_frag6_reasm: payload len = %d\n",
			    payload_len);
	goto out_fail;
out_oom:
	net_dbg_ratelimited("nf_ct_frag6_reasm: no memory for reassembly\n");
out_fail:
	return NULL;
}

/*
 * find the header just before Fragment Header.
 *
 * if success return 0 and set ...
 * (*prevhdrp): the value of "Next Header Field" in the header
 *		just before Fragment Header.
 * (*prevhoff): the offset of "Next Header Field" in the header
 *		just before Fragment Header.
 * (*fhoff)   : the offset of Fragment Header.
 *
 * Based on ipv6_skip_hdr() in net/ipv6/exthdr.c
 *
 */
static int
find_prev_fhdr(struct sk_buff *skb, u8 *prevhdrp, int *prevhoff, int *fhoff)
{
	u8 nexthdr = ipv6_hdr(skb)->nexthdr;
	const int netoff = skb_network_offset(skb);
	u8 prev_nhoff = netoff + offsetof(struct ipv6hdr, nexthdr);
	int start = netoff + sizeof(struct ipv6hdr);
	int len = skb->len - start;
	u8 prevhdr = NEXTHDR_IPV6;

	while (nexthdr != NEXTHDR_FRAGMENT) {
		struct ipv6_opt_hdr hdr;
		int hdrlen;

		if (!ipv6_ext_hdr(nexthdr)) {
			return -1;
		}
		if (nexthdr == NEXTHDR_NONE) {
			pr_debug("next header is none\n");
			return -1;
		}
		if (len < (int)sizeof(struct ipv6_opt_hdr)) {
			pr_debug("too short\n");
			return -1;
		}
		if (skb_copy_bits(skb, start, &hdr, sizeof(hdr)))
			BUG();
		if (nexthdr == NEXTHDR_AUTH)
			hdrlen = (hdr.hdrlen+2)<<2;
		else
			hdrlen = ipv6_optlen(&hdr);

		prevhdr = nexthdr;
		prev_nhoff = start;

		nexthdr = hdr.nexthdr;
		len -= hdrlen;
		start += hdrlen;
	}

	if (len < 0)
		return -1;

	*prevhdrp = prevhdr;
	*prevhoff = prev_nhoff;
	*fhoff = start;

	return 0;
}

struct sk_buff *nf_ct_frag6_gather(struct sk_buff *skb, u32 user)
{
	struct sk_buff *clone;
	struct net_device *dev = skb->dev;
	struct net *net = skb_dst(skb) ? dev_net(skb_dst(skb)->dev)
				       : dev_net(skb->dev);
	struct frag_hdr *fhdr;
	struct frag_queue *fq;
	struct ipv6hdr *hdr;
	int fhoff, nhoff;
	u8 prevhdr;
	struct sk_buff *ret_skb = NULL;

	/* Jumbo payload inhibits frag. header */
	if (ipv6_hdr(skb)->payload_len == 0) {
		pr_debug("payload len = 0\n");
		return skb;
	}

	if (find_prev_fhdr(skb, &prevhdr, &nhoff, &fhoff) < 0)
		return skb;

	clone = skb_clone(skb, GFP_ATOMIC);
	if (clone == NULL) {
		pr_debug("Can't clone skb\n");
		return skb;
	}

	NFCT_FRAG6_CB(clone)->orig = skb;

	if (!pskb_may_pull(clone, fhoff + sizeof(*fhdr))) {
		pr_debug("message is too short.\n");
		goto ret_orig;
	}

	skb_set_transport_header(clone, fhoff);
	hdr = ipv6_hdr(clone);
	fhdr = (struct frag_hdr *)skb_transport_header(clone);

	fq = fq_find(net, fhdr->identification, user, &hdr->saddr, &hdr->daddr,
		     skb->dev ? skb->dev->ifindex : 0, ip6_frag_ecn(hdr));
	if (fq == NULL) {
		pr_debug("Can't find and can't create new queue\n");
		goto ret_orig;
	}

	spin_lock_bh(&fq->q.lock);

	if (nf_ct_frag6_queue(fq, clone, fhdr, nhoff) < 0) {
		spin_unlock_bh(&fq->q.lock);
		pr_debug("Can't insert skb to queue\n");
		inet_frag_put(&fq->q, &nf_frags);
		goto ret_orig;
	}

	if (fq->q.flags == (INET_FRAG_FIRST_IN | INET_FRAG_LAST_IN) &&
	    fq->q.meat == fq->q.len) {
		ret_skb = nf_ct_frag6_reasm(fq, dev);
		if (ret_skb == NULL)
			pr_debug("Can't reassemble fragmented packets\n");
	}
	spin_unlock_bh(&fq->q.lock);

	inet_frag_put(&fq->q, &nf_frags);
	return ret_skb;

ret_orig:
	kfree_skb(clone);
	return skb;
}

void nf_ct_frag6_consume_orig(struct sk_buff *skb)
{
	struct sk_buff *s, *s2;

	for (s = NFCT_FRAG6_CB(skb)->orig; s;) {
		s2 = s->next;
		s->next = NULL;
		consume_skb(s);
		s = s2;
	}
}

static int nf_ct_net_init(struct net *net)
{
	net->nf_frag.frags.high_thresh = IPV6_FRAG_HIGH_THRESH;
	net->nf_frag.frags.low_thresh = IPV6_FRAG_LOW_THRESH;
	net->nf_frag.frags.timeout = IPV6_FRAG_TIMEOUT;
	inet_frags_init_net(&net->nf_frag.frags);

	return nf_ct_frag6_sysctl_register(net);
}

static void nf_ct_net_exit(struct net *net)
{
	nf_ct_frags6_sysctl_unregister(net);
	inet_frags_exit_net(&net->nf_frag.frags, &nf_frags);
}

static struct pernet_operations nf_ct_net_ops = {
	.init = nf_ct_net_init,
	.exit = nf_ct_net_exit,
};

int nf_ct_frag6_init(void)
{
	int ret = 0;

	nf_frags.hashfn = nf_hashfn;
	nf_frags.constructor = ip6_frag_init;
	nf_frags.destructor = NULL;
	nf_frags.skb_free = nf_skb_free;
	nf_frags.qsize = sizeof(struct frag_queue);
	nf_frags.match = ip6_frag_match;
	nf_frags.frag_expire = nf_ct_frag6_expire;
	nf_frags.frags_cache_name = nf_frags_cache_name;
	ret = inet_frags_init(&nf_frags);
	if (ret)
		goto out;
	ret = register_pernet_subsys(&nf_ct_net_ops);
	if (ret)
		inet_frags_fini(&nf_frags);

out:
	return ret;
}

void nf_ct_frag6_cleanup(void)
{
	unregister_pernet_subsys(&nf_ct_net_ops);
	inet_frags_fini(&nf_frags);
}