reassembly.c revision 81566e8322c3f6c6f9a2277fe0e440fee8d917bd 
1/*
2 *	IPv6 fragment reassembly
3 *	Linux INET6 implementation
4 *
5 *	Authors:
6 *	Pedro Roque		<roque@di.fc.ul.pt>
7 *
8 *	$Id: reassembly.c,v 1.26 2001/03/07 22:00:57 davem Exp $
9 *
10 *	Based on: net/ipv4/ip_fragment.c
11 *
12 *	This program is free software; you can redistribute it and/or
13 *      modify it under the terms of the GNU General Public License
14 *      as published by the Free Software Foundation; either version
15 *      2 of the License, or (at your option) any later version.
16 */
17
18/*
19 *	Fixes:
20 *	Andi Kleen	Make it work with multiple hosts.
21 *			More RFC compliance.
22 *
23 *      Horst von Brand Add missing #include <linux/string.h>
24 *	Alexey Kuznetsov	SMP races, threading, cleanup.
25 *	Patrick McHardy		LRU queue of frag heads for evictor.
26 *	Mitsuru KANDA @USAGI	Register inet6_protocol{}.
27 *	David Stevens and
28 *	YOSHIFUJI,H. @USAGI	Always remove fragment header to
29 *				calculate ICV correctly.
30 */
31#include <linux/errno.h>
32#include <linux/types.h>
33#include <linux/string.h>
34#include <linux/socket.h>
35#include <linux/sockios.h>
36#include <linux/jiffies.h>
37#include <linux/net.h>
38#include <linux/list.h>
39#include <linux/netdevice.h>
40#include <linux/in6.h>
41#include <linux/ipv6.h>
42#include <linux/icmpv6.h>
43#include <linux/random.h>
44#include <linux/jhash.h>
45#include <linux/skbuff.h>
46
47#include <net/sock.h>
48#include <net/snmp.h>
49
50#include <net/ipv6.h>
51#include <net/ip6_route.h>
52#include <net/protocol.h>
53#include <net/transp_v6.h>
54#include <net/rawv6.h>
55#include <net/ndisc.h>
56#include <net/addrconf.h>
57#include <net/inet_frag.h>
58
59struct ip6frag_skb_cb
60{
61	struct inet6_skb_parm	h;
62	int			offset;
63};
64
65#define FRAG6_CB(skb)	((struct ip6frag_skb_cb*)((skb)->cb))
66
67
68/*
69 *	Equivalent of ipv4 struct ipq
70 */
71
72struct frag_queue
73{
74	struct inet_frag_queue	q;
75
76	__be32			id;		/* fragment id		*/
77	struct in6_addr		saddr;
78	struct in6_addr		daddr;
79
80	int			iif;
81	unsigned int		csum;
82	__u16			nhoffset;
83};
84
85static struct inet_frags ip6_frags;
86
87int ip6_frag_nqueues(struct net *net)
88{
89	return net->ipv6.frags.nqueues;
90}
91
92int ip6_frag_mem(struct net *net)
93{
94	return atomic_read(&net->ipv6.frags.mem);
95}
96
97static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff *prev,
98			  struct net_device *dev);
99
100/*
101 * callers should be careful not to use the hash value outside the ipfrag_lock
102 * as doing so could race with ipfrag_hash_rnd being recalculated.
103 */
104static unsigned int ip6qhashfn(__be32 id, struct in6_addr *saddr,
105			       struct in6_addr *daddr)
106{
107	u32 a, b, c;
108
109	a = (__force u32)saddr->s6_addr32[0];
110	b = (__force u32)saddr->s6_addr32[1];
111	c = (__force u32)saddr->s6_addr32[2];
112
113	a += JHASH_GOLDEN_RATIO;
114	b += JHASH_GOLDEN_RATIO;
115	c += ip6_frags.rnd;
116	__jhash_mix(a, b, c);
117
118	a += (__force u32)saddr->s6_addr32[3];
119	b += (__force u32)daddr->s6_addr32[0];
120	c += (__force u32)daddr->s6_addr32[1];
121	__jhash_mix(a, b, c);
122
123	a += (__force u32)daddr->s6_addr32[2];
124	b += (__force u32)daddr->s6_addr32[3];
125	c += (__force u32)id;
126	__jhash_mix(a, b, c);
127
128	return c & (INETFRAGS_HASHSZ - 1);
129}
130
131static unsigned int ip6_hashfn(struct inet_frag_queue *q)
132{
133	struct frag_queue *fq;
134
135	fq = container_of(q, struct frag_queue, q);
136	return ip6qhashfn(fq->id, &fq->saddr, &fq->daddr);
137}
138
139int ip6_frag_match(struct inet_frag_queue *q, void *a)
140{
141	struct frag_queue *fq;
142	struct ip6_create_arg *arg = a;
143
144	fq = container_of(q, struct frag_queue, q);
145	return (fq->id == arg->id &&
146			ipv6_addr_equal(&fq->saddr, arg->src) &&
147			ipv6_addr_equal(&fq->daddr, arg->dst));
148}
149EXPORT_SYMBOL(ip6_frag_match);
150
151/* Memory Tracking Functions. */
152static inline void frag_kfree_skb(struct netns_frags *nf,
153		struct sk_buff *skb, int *work)
154{
155	if (work)
156		*work -= skb->truesize;
157	atomic_sub(skb->truesize, &nf->mem);
158	kfree_skb(skb);
159}
160
161void ip6_frag_init(struct inet_frag_queue *q, void *a)
162{
163	struct frag_queue *fq = container_of(q, struct frag_queue, q);
164	struct ip6_create_arg *arg = a;
165
166	fq->id = arg->id;
167	ipv6_addr_copy(&fq->saddr, arg->src);
168	ipv6_addr_copy(&fq->daddr, arg->dst);
169}
170EXPORT_SYMBOL(ip6_frag_init);
171
172/* Destruction primitives. */
173
174static __inline__ void fq_put(struct frag_queue *fq)
175{
176	inet_frag_put(&fq->q, &ip6_frags);
177}
178
179/* Kill fq entry. It is not destroyed immediately,
180 * because caller (and someone more) holds reference count.
181 */
182static __inline__ void fq_kill(struct frag_queue *fq)
183{
184	inet_frag_kill(&fq->q, &ip6_frags);
185}
186
187static void ip6_evictor(struct net *net, struct inet6_dev *idev)
188{
189	int evicted;
190
191	evicted = inet_frag_evictor(&net->ipv6.frags, &ip6_frags);
192	if (evicted)
193		IP6_ADD_STATS_BH(idev, IPSTATS_MIB_REASMFAILS, evicted);
194}
195
196static void ip6_frag_expire(unsigned long data)
197{
198	struct frag_queue *fq;
199	struct net_device *dev = NULL;
200
201	fq = container_of((struct inet_frag_queue *)data, struct frag_queue, q);
202
203	spin_lock(&fq->q.lock);
204
205	if (fq->q.last_in & COMPLETE)
206		goto out;
207
208	fq_kill(fq);
209
210	dev = dev_get_by_index(&init_net, fq->iif);
211	if (!dev)
212		goto out;
213
214	rcu_read_lock();
215	IP6_INC_STATS_BH(__in6_dev_get(dev), IPSTATS_MIB_REASMTIMEOUT);
216	IP6_INC_STATS_BH(__in6_dev_get(dev), IPSTATS_MIB_REASMFAILS);
217	rcu_read_unlock();
218
219	/* Don't send error if the first segment did not arrive. */
220	if (!(fq->q.last_in&FIRST_IN) || !fq->q.fragments)
221		goto out;
222
223	/*
224	   But use as source device on which LAST ARRIVED
225	   segment was received. And do not use fq->dev
226	   pointer directly, device might already disappeared.
227	 */
228	fq->q.fragments->dev = dev;
229	icmpv6_send(fq->q.fragments, ICMPV6_TIME_EXCEED, ICMPV6_EXC_FRAGTIME, 0, dev);
230out:
231	if (dev)
232		dev_put(dev);
233	spin_unlock(&fq->q.lock);
234	fq_put(fq);
235}
236
237static __inline__ struct frag_queue *
238fq_find(struct net *net, __be32 id, struct in6_addr *src, struct in6_addr *dst,
239	struct inet6_dev *idev)
240{
241	struct inet_frag_queue *q;
242	struct ip6_create_arg arg;
243	unsigned int hash;
244
245	arg.id = id;
246	arg.src = src;
247	arg.dst = dst;
248	hash = ip6qhashfn(id, src, dst);
249
250	q = inet_frag_find(&net->ipv6.frags, &ip6_frags, &arg, hash);
251	if (q == NULL)
252		goto oom;
253
254	return container_of(q, struct frag_queue, q);
255
256oom:
257	IP6_INC_STATS_BH(idev, IPSTATS_MIB_REASMFAILS);
258	return NULL;
259}
260
261static int ip6_frag_queue(struct frag_queue *fq, struct sk_buff *skb,
262			   struct frag_hdr *fhdr, int nhoff)
263{
264	struct sk_buff *prev, *next;
265	struct net_device *dev;
266	int offset, end;
267
268	if (fq->q.last_in & COMPLETE)
269		goto err;
270
271	offset = ntohs(fhdr->frag_off) & ~0x7;
272	end = offset + (ntohs(ipv6_hdr(skb)->payload_len) -
273			((u8 *)(fhdr + 1) - (u8 *)(ipv6_hdr(skb) + 1)));
274
275	if ((unsigned int)end > IPV6_MAXPLEN) {
276		IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
277				 IPSTATS_MIB_INHDRERRORS);
278		icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
279				  ((u8 *)&fhdr->frag_off -
280				   skb_network_header(skb)));
281		return -1;
282	}
283
284	if (skb->ip_summed == CHECKSUM_COMPLETE) {
285		const unsigned char *nh = skb_network_header(skb);
286		skb->csum = csum_sub(skb->csum,
287				     csum_partial(nh, (u8 *)(fhdr + 1) - nh,
288						  0));
289	}
290
291	/* Is this the final fragment? */
292	if (!(fhdr->frag_off & htons(IP6_MF))) {
293		/* If we already have some bits beyond end
294		 * or have different end, the segment is corrupted.
295		 */
296		if (end < fq->q.len ||
297		    ((fq->q.last_in & LAST_IN) && end != fq->q.len))
298			goto err;
299		fq->q.last_in |= LAST_IN;
300		fq->q.len = end;
301	} else {
302		/* Check if the fragment is rounded to 8 bytes.
303		 * Required by the RFC.
304		 */
305		if (end & 0x7) {
306			/* RFC2460 says always send parameter problem in
307			 * this case. -DaveM
308			 */
309			IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
310					 IPSTATS_MIB_INHDRERRORS);
311			icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
312					  offsetof(struct ipv6hdr, payload_len));
313			return -1;
314		}
315		if (end > fq->q.len) {
316			/* Some bits beyond end -> corruption. */
317			if (fq->q.last_in & LAST_IN)
318				goto err;
319			fq->q.len = end;
320		}
321	}
322
323	if (end == offset)
324		goto err;
325
326	/* Point into the IP datagram 'data' part. */
327	if (!pskb_pull(skb, (u8 *) (fhdr + 1) - skb->data))
328		goto err;
329
330	if (pskb_trim_rcsum(skb, end - offset))
331		goto err;
332
333	/* Find out which fragments are in front and at the back of us
334	 * in the chain of fragments so far.  We must know where to put
335	 * this fragment, right?
336	 */
337	prev = NULL;
338	for(next = fq->q.fragments; next != NULL; next = next->next) {
339		if (FRAG6_CB(next)->offset >= offset)
340			break;	/* bingo! */
341		prev = next;
342	}
343
344	/* We found where to put this one.  Check for overlap with
345	 * preceding fragment, and, if needed, align things so that
346	 * any overlaps are eliminated.
347	 */
348	if (prev) {
349		int i = (FRAG6_CB(prev)->offset + prev->len) - offset;
350
351		if (i > 0) {
352			offset += i;
353			if (end <= offset)
354				goto err;
355			if (!pskb_pull(skb, i))
356				goto err;
357			if (skb->ip_summed != CHECKSUM_UNNECESSARY)
358				skb->ip_summed = CHECKSUM_NONE;
359		}
360	}
361
362	/* Look for overlap with succeeding segments.
363	 * If we can merge fragments, do it.
364	 */
365	while (next && FRAG6_CB(next)->offset < end) {
366		int i = end - FRAG6_CB(next)->offset; /* overlap is 'i' bytes */
367
368		if (i < next->len) {
369			/* Eat head of the next overlapped fragment
370			 * and leave the loop. The next ones cannot overlap.
371			 */
372			if (!pskb_pull(next, i))
373				goto err;
374			FRAG6_CB(next)->offset += i;	/* next fragment */
375			fq->q.meat -= i;
376			if (next->ip_summed != CHECKSUM_UNNECESSARY)
377				next->ip_summed = CHECKSUM_NONE;
378			break;
379		} else {
380			struct sk_buff *free_it = next;
381
382			/* Old fragment is completely overridden with
383			 * new one drop it.
384			 */
385			next = next->next;
386
387			if (prev)
388				prev->next = next;
389			else
390				fq->q.fragments = next;
391
392			fq->q.meat -= free_it->len;
393			frag_kfree_skb(fq->q.net, free_it, NULL);
394		}
395	}
396
397	FRAG6_CB(skb)->offset = offset;
398
399	/* Insert this fragment in the chain of fragments. */
400	skb->next = next;
401	if (prev)
402		prev->next = skb;
403	else
404		fq->q.fragments = skb;
405
406	dev = skb->dev;
407	if (dev) {
408		fq->iif = dev->ifindex;
409		skb->dev = NULL;
410	}
411	fq->q.stamp = skb->tstamp;
412	fq->q.meat += skb->len;
413	atomic_add(skb->truesize, &fq->q.net->mem);
414
415	/* The first fragment.
416	 * nhoffset is obtained from the first fragment, of course.
417	 */
418	if (offset == 0) {
419		fq->nhoffset = nhoff;
420		fq->q.last_in |= FIRST_IN;
421	}
422
423	if (fq->q.last_in == (FIRST_IN | LAST_IN) && fq->q.meat == fq->q.len)
424		return ip6_frag_reasm(fq, prev, dev);
425
426	write_lock(&ip6_frags.lock);
427	list_move_tail(&fq->q.lru_list, &fq->q.net->lru_list);
428	write_unlock(&ip6_frags.lock);
429	return -1;
430
431err:
432	IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_REASMFAILS);
433	kfree_skb(skb);
434	return -1;
435}
436
437/*
438 *	Check if this packet is complete.
439 *	Returns NULL on failure by any reason, and pointer
440 *	to current nexthdr field in reassembled frame.
441 *
442 *	It is called with locked fq, and caller must check that
443 *	queue is eligible for reassembly i.e. it is not COMPLETE,
444 *	the last and the first frames arrived and all the bits are here.
445 */
446static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff *prev,
447			  struct net_device *dev)
448{
449	struct sk_buff *fp, *head = fq->q.fragments;
450	int    payload_len;
451	unsigned int nhoff;
452
453	fq_kill(fq);
454
455	/* Make the one we just received the head. */
456	if (prev) {
457		head = prev->next;
458		fp = skb_clone(head, GFP_ATOMIC);
459
460		if (!fp)
461			goto out_oom;
462
463		fp->next = head->next;
464		prev->next = fp;
465
466		skb_morph(head, fq->q.fragments);
467		head->next = fq->q.fragments->next;
468
469		kfree_skb(fq->q.fragments);
470		fq->q.fragments = head;
471	}
472
473	BUG_TRAP(head != NULL);
474	BUG_TRAP(FRAG6_CB(head)->offset == 0);
475
476	/* Unfragmented part is taken from the first segment. */
477	payload_len = ((head->data - skb_network_header(head)) -
478		       sizeof(struct ipv6hdr) + fq->q.len -
479		       sizeof(struct frag_hdr));
480	if (payload_len > IPV6_MAXPLEN)
481		goto out_oversize;
482
483	/* Head of list must not be cloned. */
484	if (skb_cloned(head) && pskb_expand_head(head, 0, 0, GFP_ATOMIC))
485		goto out_oom;
486
487	/* If the first fragment is fragmented itself, we split
488	 * it to two chunks: the first with data and paged part
489	 * and the second, holding only fragments. */
490	if (skb_shinfo(head)->frag_list) {
491		struct sk_buff *clone;
492		int i, plen = 0;
493
494		if ((clone = alloc_skb(0, GFP_ATOMIC)) == NULL)
495			goto out_oom;
496		clone->next = head->next;
497		head->next = clone;
498		skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list;
499		skb_shinfo(head)->frag_list = NULL;
500		for (i=0; i<skb_shinfo(head)->nr_frags; i++)
501			plen += skb_shinfo(head)->frags[i].size;
502		clone->len = clone->data_len = head->data_len - plen;
503		head->data_len -= clone->len;
504		head->len -= clone->len;
505		clone->csum = 0;
506		clone->ip_summed = head->ip_summed;
507		atomic_add(clone->truesize, &fq->q.net->mem);
508	}
509
510	/* We have to remove fragment header from datagram and to relocate
511	 * header in order to calculate ICV correctly. */
512	nhoff = fq->nhoffset;
513	skb_network_header(head)[nhoff] = skb_transport_header(head)[0];
514	memmove(head->head + sizeof(struct frag_hdr), head->head,
515		(head->data - head->head) - sizeof(struct frag_hdr));
516	head->mac_header += sizeof(struct frag_hdr);
517	head->network_header += sizeof(struct frag_hdr);
518
519	skb_shinfo(head)->frag_list = head->next;
520	skb_reset_transport_header(head);
521	skb_push(head, head->data - skb_network_header(head));
522	atomic_sub(head->truesize, &fq->q.net->mem);
523
524	for (fp=head->next; fp; fp = fp->next) {
525		head->data_len += fp->len;
526		head->len += fp->len;
527		if (head->ip_summed != fp->ip_summed)
528			head->ip_summed = CHECKSUM_NONE;
529		else if (head->ip_summed == CHECKSUM_COMPLETE)
530			head->csum = csum_add(head->csum, fp->csum);
531		head->truesize += fp->truesize;
532		atomic_sub(fp->truesize, &fq->q.net->mem);
533	}
534
535	head->next = NULL;
536	head->dev = dev;
537	head->tstamp = fq->q.stamp;
538	ipv6_hdr(head)->payload_len = htons(payload_len);
539	IP6CB(head)->nhoff = nhoff;
540
541	/* Yes, and fold redundant checksum back. 8) */
542	if (head->ip_summed == CHECKSUM_COMPLETE)
543		head->csum = csum_partial(skb_network_header(head),
544					  skb_network_header_len(head),
545					  head->csum);
546
547	rcu_read_lock();
548	IP6_INC_STATS_BH(__in6_dev_get(dev), IPSTATS_MIB_REASMOKS);
549	rcu_read_unlock();
550	fq->q.fragments = NULL;
551	return 1;
552
553out_oversize:
554	if (net_ratelimit())
555		printk(KERN_DEBUG "ip6_frag_reasm: payload len = %d\n", payload_len);
556	goto out_fail;
557out_oom:
558	if (net_ratelimit())
559		printk(KERN_DEBUG "ip6_frag_reasm: no memory for reassembly\n");
560out_fail:
561	rcu_read_lock();
562	IP6_INC_STATS_BH(__in6_dev_get(dev), IPSTATS_MIB_REASMFAILS);
563	rcu_read_unlock();
564	return -1;
565}
566
567static int ipv6_frag_rcv(struct sk_buff *skb)
568{
569	struct frag_hdr *fhdr;
570	struct frag_queue *fq;
571	struct ipv6hdr *hdr = ipv6_hdr(skb);
572	struct net *net;
573
574	IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_REASMREQDS);
575
576	/* Jumbo payload inhibits frag. header */
577	if (hdr->payload_len==0) {
578		IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_INHDRERRORS);
579		icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
580				  skb_network_header_len(skb));
581		return -1;
582	}
583	if (!pskb_may_pull(skb, (skb_transport_offset(skb) +
584				 sizeof(struct frag_hdr)))) {
585		IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_INHDRERRORS);
586		icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
587				  skb_network_header_len(skb));
588		return -1;
589	}
590
591	hdr = ipv6_hdr(skb);
592	fhdr = (struct frag_hdr *)skb_transport_header(skb);
593
594	if (!(fhdr->frag_off & htons(0xFFF9))) {
595		/* It is not a fragmented frame */
596		skb->transport_header += sizeof(struct frag_hdr);
597		IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_REASMOKS);
598
599		IP6CB(skb)->nhoff = (u8 *)fhdr - skb_network_header(skb);
600		return 1;
601	}
602
603	net = skb->dev->nd_net;
604	if (atomic_read(&net->ipv6.frags.mem) > net->ipv6.frags.high_thresh)
605		ip6_evictor(net, ip6_dst_idev(skb->dst));
606
607	if ((fq = fq_find(net, fhdr->identification, &hdr->saddr, &hdr->daddr,
608			  ip6_dst_idev(skb->dst))) != NULL) {
609		int ret;
610
611		spin_lock(&fq->q.lock);
612
613		ret = ip6_frag_queue(fq, skb, fhdr, IP6CB(skb)->nhoff);
614
615		spin_unlock(&fq->q.lock);
616		fq_put(fq);
617		return ret;
618	}
619
620	IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_REASMFAILS);
621	kfree_skb(skb);
622	return -1;
623}
624
625static struct inet6_protocol frag_protocol =
626{
627	.handler	=	ipv6_frag_rcv,
628	.flags		=	INET6_PROTO_NOPOLICY,
629};
630
631#ifdef CONFIG_SYSCTL
632static struct ctl_table ip6_frags_ctl_table[] = {
633	{
634		.ctl_name	= NET_IPV6_IP6FRAG_HIGH_THRESH,
635		.procname	= "ip6frag_high_thresh",
636		.data		= &init_net.ipv6.frags.high_thresh,
637		.maxlen		= sizeof(int),
638		.mode		= 0644,
639		.proc_handler	= &proc_dointvec
640	},
641	{
642		.ctl_name	= NET_IPV6_IP6FRAG_LOW_THRESH,
643		.procname	= "ip6frag_low_thresh",
644		.data		= &init_net.ipv6.frags.low_thresh,
645		.maxlen		= sizeof(int),
646		.mode		= 0644,
647		.proc_handler	= &proc_dointvec
648	},
649	{
650		.ctl_name	= NET_IPV6_IP6FRAG_TIME,
651		.procname	= "ip6frag_time",
652		.data		= &init_net.ipv6.frags.timeout,
653		.maxlen		= sizeof(int),
654		.mode		= 0644,
655		.proc_handler	= &proc_dointvec_jiffies,
656		.strategy	= &sysctl_jiffies,
657	},
658	{
659		.ctl_name	= NET_IPV6_IP6FRAG_SECRET_INTERVAL,
660		.procname	= "ip6frag_secret_interval",
661		.data		= &ip6_frags.secret_interval,
662		.maxlen		= sizeof(int),
663		.mode		= 0644,
664		.proc_handler	= &proc_dointvec_jiffies,
665		.strategy	= &sysctl_jiffies
666	},
667	{ }
668};
669
670static int ip6_frags_sysctl_register(struct net *net)
671{
672	struct ctl_table *table;
673	struct ctl_table_header *hdr;
674
675	table = ip6_frags_ctl_table;
676	if (net != &init_net) {
677		table = kmemdup(table, sizeof(ip6_frags_ctl_table), GFP_KERNEL);
678		if (table == NULL)
679			goto err_alloc;
680
681		table[0].data = &net->ipv6.frags.high_thresh;
682		table[1].data = &net->ipv6.frags.low_thresh;
683		table[2].data = &net->ipv6.frags.timeout;
684		table[3].mode &= ~0222;
685	}
686
687	hdr = register_net_sysctl_table(net, net_ipv6_ctl_path, table);
688	if (hdr == NULL)
689		goto err_reg;
690
691	net->ipv6.sysctl.frags_hdr = hdr;
692	return 0;
693
694err_reg:
695	if (net != &init_net)
696		kfree(table);
697err_alloc:
698	return -ENOMEM;
699}
700
701static void ip6_frags_sysctl_unregister(struct net *net)
702{
703	struct ctl_table *table;
704
705	table = net->ipv6.sysctl.frags_hdr->ctl_table_arg;
706	unregister_net_sysctl_table(net->ipv6.sysctl.frags_hdr);
707	kfree(table);
708}
709#else
710static inline int ip6_frags_sysctl_register(struct net *net)
711{
712	return 0;
713}
714
715static inline void ip6_frags_sysctl_unregister(struct net *net)
716{
717}
718#endif
719
720static int ipv6_frags_init_net(struct net *net)
721{
722	net->ipv6.frags.high_thresh = 256 * 1024;
723	net->ipv6.frags.low_thresh = 192 * 1024;
724	net->ipv6.frags.timeout = IPV6_FRAG_TIMEOUT;
725
726	inet_frags_init_net(&net->ipv6.frags);
727
728	return ip6_frags_sysctl_register(net);
729}
730
731static void ipv6_frags_exit_net(struct net *net)
732{
733	ip6_frags_sysctl_unregister(net);
734	inet_frags_exit_net(&net->ipv6.frags, &ip6_frags);
735}
736
737static struct pernet_operations ip6_frags_ops = {
738	.init = ipv6_frags_init_net,
739	.exit = ipv6_frags_exit_net,
740};
741
742int __init ipv6_frag_init(void)
743{
744	int ret;
745
746	ret = inet6_add_protocol(&frag_protocol, IPPROTO_FRAGMENT);
747	if (ret)
748		goto out;
749
750	register_pernet_subsys(&ip6_frags_ops);
751
752	ip6_frags.hashfn = ip6_hashfn;
753	ip6_frags.constructor = ip6_frag_init;
754	ip6_frags.destructor = NULL;
755	ip6_frags.skb_free = NULL;
756	ip6_frags.qsize = sizeof(struct frag_queue);
757	ip6_frags.match = ip6_frag_match;
758	ip6_frags.frag_expire = ip6_frag_expire;
759	ip6_frags.secret_interval = 10 * 60 * HZ;
760	inet_frags_init(&ip6_frags);
761out:
762	return ret;
763}
764
765void ipv6_frag_exit(void)
766{
767	inet_frags_fini(&ip6_frags);
768	unregister_pernet_subsys(&ip6_frags_ops);
769	inet6_del_protocol(&frag_protocol, IPPROTO_FRAGMENT);
770}
771