xref: /openbmc/linux/net/ipv6/reassembly.c (revision 3366e358) 
1 /*
2  *	IPv6 fragment reassembly
3  *	Linux INET6 implementation
4  *
5  *	Authors:
6  *	Pedro Roque		<roque@di.fc.ul.pt>
7  *
8  *	Based on: net/ipv4/ip_fragment.c
9  *
10  *	This program is free software; you can redistribute it and/or
11  *      modify it under the terms of the GNU General Public License
12  *      as published by the Free Software Foundation; either version
13  *      2 of the License, or (at your option) any later version.
14  */
15 
16 /*
17  *	Fixes:
18  *	Andi Kleen	Make it work with multiple hosts.
19  *			More RFC compliance.
20  *
21  *      Horst von Brand Add missing #include <linux/string.h>
22  *	Alexey Kuznetsov	SMP races, threading, cleanup.
23  *	Patrick McHardy		LRU queue of frag heads for evictor.
24  *	Mitsuru KANDA @USAGI	Register inet6_protocol{}.
25  *	David Stevens and
26  *	YOSHIFUJI,H. @USAGI	Always remove fragment header to
27  *				calculate ICV correctly.
28  */
29 #include <linux/errno.h>
30 #include <linux/types.h>
31 #include <linux/string.h>
32 #include <linux/socket.h>
33 #include <linux/sockios.h>
34 #include <linux/jiffies.h>
35 #include <linux/net.h>
36 #include <linux/list.h>
37 #include <linux/netdevice.h>
38 #include <linux/in6.h>
39 #include <linux/ipv6.h>
40 #include <linux/icmpv6.h>
41 #include <linux/random.h>
42 #include <linux/jhash.h>
43 #include <linux/skbuff.h>
44 
45 #include <net/sock.h>
46 #include <net/snmp.h>
47 
48 #include <net/ipv6.h>
49 #include <net/ip6_route.h>
50 #include <net/protocol.h>
51 #include <net/transp_v6.h>
52 #include <net/rawv6.h>
53 #include <net/ndisc.h>
54 #include <net/addrconf.h>
55 #include <net/inet_frag.h>
56 
57 struct ip6frag_skb_cb
58 {
59 	struct inet6_skb_parm	h;
60 	int			offset;
61 };
62 
63 #define FRAG6_CB(skb)	((struct ip6frag_skb_cb*)((skb)->cb))
64 
65 
66 /*
67  *	Equivalent of ipv4 struct ipq
68  */
69 
70 struct frag_queue
71 {
72 	struct inet_frag_queue	q;
73 
74 	__be32			id;		/* fragment id		*/
75 	u32			user;
76 	struct in6_addr		saddr;
77 	struct in6_addr		daddr;
78 
79 	int			iif;
80 	unsigned int		csum;
81 	__u16			nhoffset;
82 };
83 
84 static struct inet_frags ip6_frags;
85 
86 int ip6_frag_nqueues(struct net *net)
87 {
88 	return net->ipv6.frags.nqueues;
89 }
90 
91 int ip6_frag_mem(struct net *net)
92 {
93 	return atomic_read(&net->ipv6.frags.mem);
94 }
95 
96 static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff *prev,
97 			  struct net_device *dev);
98 
99 /*
100  * callers should be careful not to use the hash value outside the ipfrag_lock
101  * as doing so could race with ipfrag_hash_rnd being recalculated.
102  */
103 unsigned int inet6_hash_frag(__be32 id, const struct in6_addr *saddr,
104 			     const struct in6_addr *daddr, u32 rnd)
105 {
106 	u32 a, b, c;
107 
108 	a = (__force u32)saddr->s6_addr32[0];
109 	b = (__force u32)saddr->s6_addr32[1];
110 	c = (__force u32)saddr->s6_addr32[2];
111 
112 	a += JHASH_GOLDEN_RATIO;
113 	b += JHASH_GOLDEN_RATIO;
114 	c += rnd;
115 	__jhash_mix(a, b, c);
116 
117 	a += (__force u32)saddr->s6_addr32[3];
118 	b += (__force u32)daddr->s6_addr32[0];
119 	c += (__force u32)daddr->s6_addr32[1];
120 	__jhash_mix(a, b, c);
121 
122 	a += (__force u32)daddr->s6_addr32[2];
123 	b += (__force u32)daddr->s6_addr32[3];
124 	c += (__force u32)id;
125 	__jhash_mix(a, b, c);
126 
127 	return c & (INETFRAGS_HASHSZ - 1);
128 }
129 EXPORT_SYMBOL_GPL(inet6_hash_frag);
130 
131 static 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 inet6_hash_frag(fq->id, &fq->saddr, &fq->daddr, ip6_frags.rnd);
137 }
138 
139 int 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 && fq->user == arg->user &&
146 			ipv6_addr_equal(&fq->saddr, arg->src) &&
147 			ipv6_addr_equal(&fq->daddr, arg->dst));
148 }
149 EXPORT_SYMBOL(ip6_frag_match);
150 
151 /* Memory Tracking Functions. */
152 static 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 
161 void 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 	fq->user = arg->user;
168 	ipv6_addr_copy(&fq->saddr, arg->src);
169 	ipv6_addr_copy(&fq->daddr, arg->dst);
170 }
171 EXPORT_SYMBOL(ip6_frag_init);
172 
173 /* Destruction primitives. */
174 
175 static __inline__ void fq_put(struct frag_queue *fq)
176 {
177 	inet_frag_put(&fq->q, &ip6_frags);
178 }
179 
180 /* Kill fq entry. It is not destroyed immediately,
181  * because caller (and someone more) holds reference count.
182  */
183 static __inline__ void fq_kill(struct frag_queue *fq)
184 {
185 	inet_frag_kill(&fq->q, &ip6_frags);
186 }
187 
188 static void ip6_evictor(struct net *net, struct inet6_dev *idev)
189 {
190 	int evicted;
191 
192 	evicted = inet_frag_evictor(&net->ipv6.frags, &ip6_frags);
193 	if (evicted)
194 		IP6_ADD_STATS_BH(net, idev, IPSTATS_MIB_REASMFAILS, evicted);
195 }
196 
197 static void ip6_frag_expire(unsigned long data)
198 {
199 	struct frag_queue *fq;
200 	struct net_device *dev = NULL;
201 	struct net *net;
202 
203 	fq = container_of((struct inet_frag_queue *)data, struct frag_queue, q);
204 
205 	spin_lock(&fq->q.lock);
206 
207 	if (fq->q.last_in & INET_FRAG_COMPLETE)
208 		goto out;
209 
210 	fq_kill(fq);
211 
212 	net = container_of(fq->q.net, struct net, ipv6.frags);
213 	rcu_read_lock();
214 	dev = dev_get_by_index_rcu(net, fq->iif);
215 	if (!dev)
216 		goto out_rcu_unlock;
217 
218 	IP6_INC_STATS_BH(net, __in6_dev_get(dev), IPSTATS_MIB_REASMTIMEOUT);
219 	IP6_INC_STATS_BH(net, __in6_dev_get(dev), IPSTATS_MIB_REASMFAILS);
220 
221 	/* Don't send error if the first segment did not arrive. */
222 	if (!(fq->q.last_in & INET_FRAG_FIRST_IN) || !fq->q.fragments)
223 		goto out_rcu_unlock;
224 
225 	/*
226 	   But use as source device on which LAST ARRIVED
227 	   segment was received. And do not use fq->dev
228 	   pointer directly, device might already disappeared.
229 	 */
230 	fq->q.fragments->dev = dev;
231 	icmpv6_send(fq->q.fragments, ICMPV6_TIME_EXCEED, ICMPV6_EXC_FRAGTIME, 0);
232 out_rcu_unlock:
233 	rcu_read_unlock();
234 out:
235 	spin_unlock(&fq->q.lock);
236 	fq_put(fq);
237 }
238 
239 static __inline__ struct frag_queue *
240 fq_find(struct net *net, __be32 id, struct in6_addr *src, struct in6_addr *dst)
241 {
242 	struct inet_frag_queue *q;
243 	struct ip6_create_arg arg;
244 	unsigned int hash;
245 
246 	arg.id = id;
247 	arg.user = IP6_DEFRAG_LOCAL_DELIVER;
248 	arg.src = src;
249 	arg.dst = dst;
250 
251 	read_lock(&ip6_frags.lock);
252 	hash = inet6_hash_frag(id, src, dst, ip6_frags.rnd);
253 
254 	q = inet_frag_find(&net->ipv6.frags, &ip6_frags, &arg, hash);
255 	if (q == NULL)
256 		return NULL;
257 
258 	return container_of(q, struct frag_queue, q);
259 }
260 
261 static 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 	struct net *net = dev_net(skb_dst(skb)->dev);
268 
269 	if (fq->q.last_in & INET_FRAG_COMPLETE)
270 		goto err;
271 
272 	offset = ntohs(fhdr->frag_off) & ~0x7;
273 	end = offset + (ntohs(ipv6_hdr(skb)->payload_len) -
274 			((u8 *)(fhdr + 1) - (u8 *)(ipv6_hdr(skb) + 1)));
275 
276 	if ((unsigned int)end > IPV6_MAXPLEN) {
277 		IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
278 				 IPSTATS_MIB_INHDRERRORS);
279 		icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
280 				  ((u8 *)&fhdr->frag_off -
281 				   skb_network_header(skb)));
282 		return -1;
283 	}
284 
285 	if (skb->ip_summed == CHECKSUM_COMPLETE) {
286 		const unsigned char *nh = skb_network_header(skb);
287 		skb->csum = csum_sub(skb->csum,
288 				     csum_partial(nh, (u8 *)(fhdr + 1) - nh,
289 						  0));
290 	}
291 
292 	/* Is this the final fragment? */
293 	if (!(fhdr->frag_off & htons(IP6_MF))) {
294 		/* If we already have some bits beyond end
295 		 * or have different end, the segment is corrupted.
296 		 */
297 		if (end < fq->q.len ||
298 		    ((fq->q.last_in & INET_FRAG_LAST_IN) && end != fq->q.len))
299 			goto err;
300 		fq->q.last_in |= INET_FRAG_LAST_IN;
301 		fq->q.len = end;
302 	} else {
303 		/* Check if the fragment is rounded to 8 bytes.
304 		 * Required by the RFC.
305 		 */
306 		if (end & 0x7) {
307 			/* RFC2460 says always send parameter problem in
308 			 * this case. -DaveM
309 			 */
310 			IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
311 					 IPSTATS_MIB_INHDRERRORS);
312 			icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
313 					  offsetof(struct ipv6hdr, payload_len));
314 			return -1;
315 		}
316 		if (end > fq->q.len) {
317 			/* Some bits beyond end -> corruption. */
318 			if (fq->q.last_in & INET_FRAG_LAST_IN)
319 				goto err;
320 			fq->q.len = end;
321 		}
322 	}
323 
324 	if (end == offset)
325 		goto err;
326 
327 	/* Point into the IP datagram 'data' part. */
328 	if (!pskb_pull(skb, (u8 *) (fhdr + 1) - skb->data))
329 		goto err;
330 
331 	if (pskb_trim_rcsum(skb, end - offset))
332 		goto err;
333 
334 	/* Find out which fragments are in front and at the back of us
335 	 * in the chain of fragments so far.  We must know where to put
336 	 * this fragment, right?
337 	 */
338 	prev = NULL;
339 	for(next = fq->q.fragments; next != NULL; next = next->next) {
340 		if (FRAG6_CB(next)->offset >= offset)
341 			break;	/* bingo! */
342 		prev = next;
343 	}
344 
345 	/* We found where to put this one.  Check for overlap with
346 	 * preceding fragment, and, if needed, align things so that
347 	 * any overlaps are eliminated.
348 	 */
349 	if (prev) {
350 		int i = (FRAG6_CB(prev)->offset + prev->len) - offset;
351 
352 		if (i > 0) {
353 			offset += i;
354 			if (end <= offset)
355 				goto err;
356 			if (!pskb_pull(skb, i))
357 				goto err;
358 			if (skb->ip_summed != CHECKSUM_UNNECESSARY)
359 				skb->ip_summed = CHECKSUM_NONE;
360 		}
361 	}
362 
363 	/* Look for overlap with succeeding segments.
364 	 * If we can merge fragments, do it.
365 	 */
366 	while (next && FRAG6_CB(next)->offset < end) {
367 		int i = end - FRAG6_CB(next)->offset; /* overlap is 'i' bytes */
368 
369 		if (i < next->len) {
370 			/* Eat head of the next overlapped fragment
371 			 * and leave the loop. The next ones cannot overlap.
372 			 */
373 			if (!pskb_pull(next, i))
374 				goto err;
375 			FRAG6_CB(next)->offset += i;	/* next fragment */
376 			fq->q.meat -= i;
377 			if (next->ip_summed != CHECKSUM_UNNECESSARY)
378 				next->ip_summed = CHECKSUM_NONE;
379 			break;
380 		} else {
381 			struct sk_buff *free_it = next;
382 
383 			/* Old fragment is completely overridden with
384 			 * new one drop it.
385 			 */
386 			next = next->next;
387 
388 			if (prev)
389 				prev->next = next;
390 			else
391 				fq->q.fragments = next;
392 
393 			fq->q.meat -= free_it->len;
394 			frag_kfree_skb(fq->q.net, free_it, NULL);
395 		}
396 	}
397 
398 	FRAG6_CB(skb)->offset = offset;
399 
400 	/* Insert this fragment in the chain of fragments. */
401 	skb->next = next;
402 	if (prev)
403 		prev->next = skb;
404 	else
405 		fq->q.fragments = skb;
406 
407 	dev = skb->dev;
408 	if (dev) {
409 		fq->iif = dev->ifindex;
410 		skb->dev = NULL;
411 	}
412 	fq->q.stamp = skb->tstamp;
413 	fq->q.meat += skb->len;
414 	atomic_add(skb->truesize, &fq->q.net->mem);
415 
416 	/* The first fragment.
417 	 * nhoffset is obtained from the first fragment, of course.
418 	 */
419 	if (offset == 0) {
420 		fq->nhoffset = nhoff;
421 		fq->q.last_in |= INET_FRAG_FIRST_IN;
422 	}
423 
424 	if (fq->q.last_in == (INET_FRAG_FIRST_IN | INET_FRAG_LAST_IN) &&
425 	    fq->q.meat == fq->q.len)
426 		return ip6_frag_reasm(fq, prev, dev);
427 
428 	write_lock(&ip6_frags.lock);
429 	list_move_tail(&fq->q.lru_list, &fq->q.net->lru_list);
430 	write_unlock(&ip6_frags.lock);
431 	return -1;
432 
433 err:
434 	IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
435 		      IPSTATS_MIB_REASMFAILS);
436 	kfree_skb(skb);
437 	return -1;
438 }
439 
440 /*
441  *	Check if this packet is complete.
442  *	Returns NULL on failure by any reason, and pointer
443  *	to current nexthdr field in reassembled frame.
444  *
445  *	It is called with locked fq, and caller must check that
446  *	queue is eligible for reassembly i.e. it is not COMPLETE,
447  *	the last and the first frames arrived and all the bits are here.
448  */
449 static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff *prev,
450 			  struct net_device *dev)
451 {
452 	struct net *net = container_of(fq->q.net, struct net, ipv6.frags);
453 	struct sk_buff *fp, *head = fq->q.fragments;
454 	int    payload_len;
455 	unsigned int nhoff;
456 
457 	fq_kill(fq);
458 
459 	/* Make the one we just received the head. */
460 	if (prev) {
461 		head = prev->next;
462 		fp = skb_clone(head, GFP_ATOMIC);
463 
464 		if (!fp)
465 			goto out_oom;
466 
467 		fp->next = head->next;
468 		prev->next = fp;
469 
470 		skb_morph(head, fq->q.fragments);
471 		head->next = fq->q.fragments->next;
472 
473 		kfree_skb(fq->q.fragments);
474 		fq->q.fragments = head;
475 	}
476 
477 	WARN_ON(head == NULL);
478 	WARN_ON(FRAG6_CB(head)->offset != 0);
479 
480 	/* Unfragmented part is taken from the first segment. */
481 	payload_len = ((head->data - skb_network_header(head)) -
482 		       sizeof(struct ipv6hdr) + fq->q.len -
483 		       sizeof(struct frag_hdr));
484 	if (payload_len > IPV6_MAXPLEN)
485 		goto out_oversize;
486 
487 	/* Head of list must not be cloned. */
488 	if (skb_cloned(head) && pskb_expand_head(head, 0, 0, GFP_ATOMIC))
489 		goto out_oom;
490 
491 	/* If the first fragment is fragmented itself, we split
492 	 * it to two chunks: the first with data and paged part
493 	 * and the second, holding only fragments. */
494 	if (skb_has_frags(head)) {
495 		struct sk_buff *clone;
496 		int i, plen = 0;
497 
498 		if ((clone = alloc_skb(0, GFP_ATOMIC)) == NULL)
499 			goto out_oom;
500 		clone->next = head->next;
501 		head->next = clone;
502 		skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list;
503 		skb_frag_list_init(head);
504 		for (i=0; i<skb_shinfo(head)->nr_frags; i++)
505 			plen += skb_shinfo(head)->frags[i].size;
506 		clone->len = clone->data_len = head->data_len - plen;
507 		head->data_len -= clone->len;
508 		head->len -= clone->len;
509 		clone->csum = 0;
510 		clone->ip_summed = head->ip_summed;
511 		atomic_add(clone->truesize, &fq->q.net->mem);
512 	}
513 
514 	/* We have to remove fragment header from datagram and to relocate
515 	 * header in order to calculate ICV correctly. */
516 	nhoff = fq->nhoffset;
517 	skb_network_header(head)[nhoff] = skb_transport_header(head)[0];
518 	memmove(head->head + sizeof(struct frag_hdr), head->head,
519 		(head->data - head->head) - sizeof(struct frag_hdr));
520 	head->mac_header += sizeof(struct frag_hdr);
521 	head->network_header += sizeof(struct frag_hdr);
522 
523 	skb_shinfo(head)->frag_list = head->next;
524 	skb_reset_transport_header(head);
525 	skb_push(head, head->data - skb_network_header(head));
526 	atomic_sub(head->truesize, &fq->q.net->mem);
527 
528 	for (fp=head->next; fp; fp = fp->next) {
529 		head->data_len += fp->len;
530 		head->len += fp->len;
531 		if (head->ip_summed != fp->ip_summed)
532 			head->ip_summed = CHECKSUM_NONE;
533 		else if (head->ip_summed == CHECKSUM_COMPLETE)
534 			head->csum = csum_add(head->csum, fp->csum);
535 		head->truesize += fp->truesize;
536 		atomic_sub(fp->truesize, &fq->q.net->mem);
537 	}
538 
539 	head->next = NULL;
540 	head->dev = dev;
541 	head->tstamp = fq->q.stamp;
542 	ipv6_hdr(head)->payload_len = htons(payload_len);
543 	IP6CB(head)->nhoff = nhoff;
544 
545 	/* Yes, and fold redundant checksum back. 8) */
546 	if (head->ip_summed == CHECKSUM_COMPLETE)
547 		head->csum = csum_partial(skb_network_header(head),
548 					  skb_network_header_len(head),
549 					  head->csum);
550 
551 	rcu_read_lock();
552 	IP6_INC_STATS_BH(net, __in6_dev_get(dev), IPSTATS_MIB_REASMOKS);
553 	rcu_read_unlock();
554 	fq->q.fragments = NULL;
555 	return 1;
556 
557 out_oversize:
558 	if (net_ratelimit())
559 		printk(KERN_DEBUG "ip6_frag_reasm: payload len = %d\n", payload_len);
560 	goto out_fail;
561 out_oom:
562 	if (net_ratelimit())
563 		printk(KERN_DEBUG "ip6_frag_reasm: no memory for reassembly\n");
564 out_fail:
565 	rcu_read_lock();
566 	IP6_INC_STATS_BH(net, __in6_dev_get(dev), IPSTATS_MIB_REASMFAILS);
567 	rcu_read_unlock();
568 	return -1;
569 }
570 
571 static int ipv6_frag_rcv(struct sk_buff *skb)
572 {
573 	struct frag_hdr *fhdr;
574 	struct frag_queue *fq;
575 	struct ipv6hdr *hdr = ipv6_hdr(skb);
576 	struct net *net = dev_net(skb_dst(skb)->dev);
577 
578 	IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_REASMREQDS);
579 
580 	/* Jumbo payload inhibits frag. header */
581 	if (hdr->payload_len==0)
582 		goto fail_hdr;
583 
584 	if (!pskb_may_pull(skb, (skb_transport_offset(skb) +
585 				 sizeof(struct frag_hdr))))
586 		goto fail_hdr;
587 
588 	hdr = ipv6_hdr(skb);
589 	fhdr = (struct frag_hdr *)skb_transport_header(skb);
590 
591 	if (!(fhdr->frag_off & htons(0xFFF9))) {
592 		/* It is not a fragmented frame */
593 		skb->transport_header += sizeof(struct frag_hdr);
594 		IP6_INC_STATS_BH(net,
595 				 ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_REASMOKS);
596 
597 		IP6CB(skb)->nhoff = (u8 *)fhdr - skb_network_header(skb);
598 		return 1;
599 	}
600 
601 	if (atomic_read(&net->ipv6.frags.mem) > net->ipv6.frags.high_thresh)
602 		ip6_evictor(net, ip6_dst_idev(skb_dst(skb)));
603 
604 	fq = fq_find(net, fhdr->identification, &hdr->saddr, &hdr->daddr);
605 	if (fq != NULL) {
606 		int ret;
607 
608 		spin_lock(&fq->q.lock);
609 
610 		ret = ip6_frag_queue(fq, skb, fhdr, IP6CB(skb)->nhoff);
611 
612 		spin_unlock(&fq->q.lock);
613 		fq_put(fq);
614 		return ret;
615 	}
616 
617 	IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_REASMFAILS);
618 	kfree_skb(skb);
619 	return -1;
620 
621 fail_hdr:
622 	IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_INHDRERRORS);
623 	icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, skb_network_header_len(skb));
624 	return -1;
625 }
626 
627 static const struct inet6_protocol frag_protocol =
628 {
629 	.handler	=	ipv6_frag_rcv,
630 	.flags		=	INET6_PROTO_NOPOLICY,
631 };
632 
633 #ifdef CONFIG_SYSCTL
634 static struct ctl_table ip6_frags_ns_ctl_table[] = {
635 	{
636 		.procname	= "ip6frag_high_thresh",
637 		.data		= &init_net.ipv6.frags.high_thresh,
638 		.maxlen		= sizeof(int),
639 		.mode		= 0644,
640 		.proc_handler	= proc_dointvec
641 	},
642 	{
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 		.procname	= "ip6frag_time",
651 		.data		= &init_net.ipv6.frags.timeout,
652 		.maxlen		= sizeof(int),
653 		.mode		= 0644,
654 		.proc_handler	= proc_dointvec_jiffies,
655 	},
656 	{ }
657 };
658 
659 static struct ctl_table ip6_frags_ctl_table[] = {
660 	{
661 		.procname	= "ip6frag_secret_interval",
662 		.data		= &ip6_frags.secret_interval,
663 		.maxlen		= sizeof(int),
664 		.mode		= 0644,
665 		.proc_handler	= proc_dointvec_jiffies,
666 	},
667 	{ }
668 };
669 
670 static int __net_init ip6_frags_ns_sysctl_register(struct net *net)
671 {
672 	struct ctl_table *table;
673 	struct ctl_table_header *hdr;
674 
675 	table = ip6_frags_ns_ctl_table;
676 	if (!net_eq(net, &init_net)) {
677 		table = kmemdup(table, sizeof(ip6_frags_ns_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 	}
685 
686 	hdr = register_net_sysctl_table(net, net_ipv6_ctl_path, table);
687 	if (hdr == NULL)
688 		goto err_reg;
689 
690 	net->ipv6.sysctl.frags_hdr = hdr;
691 	return 0;
692 
693 err_reg:
694 	if (!net_eq(net, &init_net))
695 		kfree(table);
696 err_alloc:
697 	return -ENOMEM;
698 }
699 
700 static void __net_exit ip6_frags_ns_sysctl_unregister(struct net *net)
701 {
702 	struct ctl_table *table;
703 
704 	table = net->ipv6.sysctl.frags_hdr->ctl_table_arg;
705 	unregister_net_sysctl_table(net->ipv6.sysctl.frags_hdr);
706 	if (!net_eq(net, &init_net))
707 		kfree(table);
708 }
709 
710 static struct ctl_table_header *ip6_ctl_header;
711 
712 static int ip6_frags_sysctl_register(void)
713 {
714 	ip6_ctl_header = register_net_sysctl_rotable(net_ipv6_ctl_path,
715 			ip6_frags_ctl_table);
716 	return ip6_ctl_header == NULL ? -ENOMEM : 0;
717 }
718 
719 static void ip6_frags_sysctl_unregister(void)
720 {
721 	unregister_net_sysctl_table(ip6_ctl_header);
722 }
723 #else
724 static inline int ip6_frags_ns_sysctl_register(struct net *net)
725 {
726 	return 0;
727 }
728 
729 static inline void ip6_frags_ns_sysctl_unregister(struct net *net)
730 {
731 }
732 
733 static inline int ip6_frags_sysctl_register(void)
734 {
735 	return 0;
736 }
737 
738 static inline void ip6_frags_sysctl_unregister(void)
739 {
740 }
741 #endif
742 
743 static int __net_init ipv6_frags_init_net(struct net *net)
744 {
745 	net->ipv6.frags.high_thresh = IPV6_FRAG_HIGH_THRESH;
746 	net->ipv6.frags.low_thresh = IPV6_FRAG_LOW_THRESH;
747 	net->ipv6.frags.timeout = IPV6_FRAG_TIMEOUT;
748 
749 	inet_frags_init_net(&net->ipv6.frags);
750 
751 	return ip6_frags_ns_sysctl_register(net);
752 }
753 
754 static void __net_exit ipv6_frags_exit_net(struct net *net)
755 {
756 	ip6_frags_ns_sysctl_unregister(net);
757 	inet_frags_exit_net(&net->ipv6.frags, &ip6_frags);
758 }
759 
760 static struct pernet_operations ip6_frags_ops = {
761 	.init = ipv6_frags_init_net,
762 	.exit = ipv6_frags_exit_net,
763 };
764 
765 int __init ipv6_frag_init(void)
766 {
767 	int ret;
768 
769 	ret = inet6_add_protocol(&frag_protocol, IPPROTO_FRAGMENT);
770 	if (ret)
771 		goto out;
772 
773 	ret = ip6_frags_sysctl_register();
774 	if (ret)
775 		goto err_sysctl;
776 
777 	ret = register_pernet_subsys(&ip6_frags_ops);
778 	if (ret)
779 		goto err_pernet;
780 
781 	ip6_frags.hashfn = ip6_hashfn;
782 	ip6_frags.constructor = ip6_frag_init;
783 	ip6_frags.destructor = NULL;
784 	ip6_frags.skb_free = NULL;
785 	ip6_frags.qsize = sizeof(struct frag_queue);
786 	ip6_frags.match = ip6_frag_match;
787 	ip6_frags.frag_expire = ip6_frag_expire;
788 	ip6_frags.secret_interval = 10 * 60 * HZ;
789 	inet_frags_init(&ip6_frags);
790 out:
791 	return ret;
792 
793 err_pernet:
794 	ip6_frags_sysctl_unregister();
795 err_sysctl:
796 	inet6_del_protocol(&frag_protocol, IPPROTO_FRAGMENT);
797 	goto out;
798 }
799 
800 void ipv6_frag_exit(void)
801 {
802 	inet_frags_fini(&ip6_frags);
803 	ip6_frags_sysctl_unregister();
804 	unregister_pernet_subsys(&ip6_frags_ops);
805 	inet6_del_protocol(&frag_protocol, IPPROTO_FRAGMENT);
806 }
807