xref: /openbmc/linux/net/ipv6/reassembly.c (revision 22246614)
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 
59 struct 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 
72 struct 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 
85 static struct inet_frags ip6_frags;
86 
87 int ip6_frag_nqueues(struct net *net)
88 {
89 	return net->ipv6.frags.nqueues;
90 }
91 
92 int ip6_frag_mem(struct net *net)
93 {
94 	return atomic_read(&net->ipv6.frags.mem);
95 }
96 
97 static 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  */
104 static 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 
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 ip6qhashfn(fq->id, &fq->saddr, &fq->daddr);
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 &&
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 	ipv6_addr_copy(&fq->saddr, arg->src);
168 	ipv6_addr_copy(&fq->daddr, arg->dst);
169 }
170 EXPORT_SYMBOL(ip6_frag_init);
171 
172 /* Destruction primitives. */
173 
174 static __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  */
182 static __inline__ void fq_kill(struct frag_queue *fq)
183 {
184 	inet_frag_kill(&fq->q, &ip6_frags);
185 }
186 
187 static 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 
196 static void ip6_frag_expire(unsigned long data)
197 {
198 	struct frag_queue *fq;
199 	struct net_device *dev = NULL;
200 	struct net *net;
201 
202 	fq = container_of((struct inet_frag_queue *)data, struct frag_queue, q);
203 
204 	spin_lock(&fq->q.lock);
205 
206 	if (fq->q.last_in & INET_FRAG_COMPLETE)
207 		goto out;
208 
209 	fq_kill(fq);
210 
211 	net = container_of(fq->q.net, struct net, ipv6.frags);
212 	dev = dev_get_by_index(net, fq->iif);
213 	if (!dev)
214 		goto out;
215 
216 	rcu_read_lock();
217 	IP6_INC_STATS_BH(__in6_dev_get(dev), IPSTATS_MIB_REASMTIMEOUT);
218 	IP6_INC_STATS_BH(__in6_dev_get(dev), IPSTATS_MIB_REASMFAILS);
219 	rcu_read_unlock();
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;
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, dev);
232 out:
233 	if (dev)
234 		dev_put(dev);
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 	struct inet6_dev *idev)
242 {
243 	struct inet_frag_queue *q;
244 	struct ip6_create_arg arg;
245 	unsigned int hash;
246 
247 	arg.id = id;
248 	arg.src = src;
249 	arg.dst = dst;
250 	hash = ip6qhashfn(id, src, dst);
251 
252 	q = inet_frag_find(&net->ipv6.frags, &ip6_frags, &arg, hash);
253 	if (q == NULL)
254 		goto oom;
255 
256 	return container_of(q, struct frag_queue, q);
257 
258 oom:
259 	IP6_INC_STATS_BH(idev, IPSTATS_MIB_REASMFAILS);
260 	return NULL;
261 }
262 
263 static int ip6_frag_queue(struct frag_queue *fq, struct sk_buff *skb,
264 			   struct frag_hdr *fhdr, int nhoff)
265 {
266 	struct sk_buff *prev, *next;
267 	struct net_device *dev;
268 	int offset, end;
269 
270 	if (fq->q.last_in & INET_FRAG_COMPLETE)
271 		goto err;
272 
273 	offset = ntohs(fhdr->frag_off) & ~0x7;
274 	end = offset + (ntohs(ipv6_hdr(skb)->payload_len) -
275 			((u8 *)(fhdr + 1) - (u8 *)(ipv6_hdr(skb) + 1)));
276 
277 	if ((unsigned int)end > IPV6_MAXPLEN) {
278 		IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
279 				 IPSTATS_MIB_INHDRERRORS);
280 		icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
281 				  ((u8 *)&fhdr->frag_off -
282 				   skb_network_header(skb)));
283 		return -1;
284 	}
285 
286 	if (skb->ip_summed == CHECKSUM_COMPLETE) {
287 		const unsigned char *nh = skb_network_header(skb);
288 		skb->csum = csum_sub(skb->csum,
289 				     csum_partial(nh, (u8 *)(fhdr + 1) - nh,
290 						  0));
291 	}
292 
293 	/* Is this the final fragment? */
294 	if (!(fhdr->frag_off & htons(IP6_MF))) {
295 		/* If we already have some bits beyond end
296 		 * or have different end, the segment is corrupted.
297 		 */
298 		if (end < fq->q.len ||
299 		    ((fq->q.last_in & INET_FRAG_LAST_IN) && end != fq->q.len))
300 			goto err;
301 		fq->q.last_in |= INET_FRAG_LAST_IN;
302 		fq->q.len = end;
303 	} else {
304 		/* Check if the fragment is rounded to 8 bytes.
305 		 * Required by the RFC.
306 		 */
307 		if (end & 0x7) {
308 			/* RFC2460 says always send parameter problem in
309 			 * this case. -DaveM
310 			 */
311 			IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
312 					 IPSTATS_MIB_INHDRERRORS);
313 			icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
314 					  offsetof(struct ipv6hdr, payload_len));
315 			return -1;
316 		}
317 		if (end > fq->q.len) {
318 			/* Some bits beyond end -> corruption. */
319 			if (fq->q.last_in & INET_FRAG_LAST_IN)
320 				goto err;
321 			fq->q.len = end;
322 		}
323 	}
324 
325 	if (end == offset)
326 		goto err;
327 
328 	/* Point into the IP datagram 'data' part. */
329 	if (!pskb_pull(skb, (u8 *) (fhdr + 1) - skb->data))
330 		goto err;
331 
332 	if (pskb_trim_rcsum(skb, end - offset))
333 		goto err;
334 
335 	/* Find out which fragments are in front and at the back of us
336 	 * in the chain of fragments so far.  We must know where to put
337 	 * this fragment, right?
338 	 */
339 	prev = NULL;
340 	for(next = fq->q.fragments; next != NULL; next = next->next) {
341 		if (FRAG6_CB(next)->offset >= offset)
342 			break;	/* bingo! */
343 		prev = next;
344 	}
345 
346 	/* We found where to put this one.  Check for overlap with
347 	 * preceding fragment, and, if needed, align things so that
348 	 * any overlaps are eliminated.
349 	 */
350 	if (prev) {
351 		int i = (FRAG6_CB(prev)->offset + prev->len) - offset;
352 
353 		if (i > 0) {
354 			offset += i;
355 			if (end <= offset)
356 				goto err;
357 			if (!pskb_pull(skb, i))
358 				goto err;
359 			if (skb->ip_summed != CHECKSUM_UNNECESSARY)
360 				skb->ip_summed = CHECKSUM_NONE;
361 		}
362 	}
363 
364 	/* Look for overlap with succeeding segments.
365 	 * If we can merge fragments, do it.
366 	 */
367 	while (next && FRAG6_CB(next)->offset < end) {
368 		int i = end - FRAG6_CB(next)->offset; /* overlap is 'i' bytes */
369 
370 		if (i < next->len) {
371 			/* Eat head of the next overlapped fragment
372 			 * and leave the loop. The next ones cannot overlap.
373 			 */
374 			if (!pskb_pull(next, i))
375 				goto err;
376 			FRAG6_CB(next)->offset += i;	/* next fragment */
377 			fq->q.meat -= i;
378 			if (next->ip_summed != CHECKSUM_UNNECESSARY)
379 				next->ip_summed = CHECKSUM_NONE;
380 			break;
381 		} else {
382 			struct sk_buff *free_it = next;
383 
384 			/* Old fragment is completely overridden with
385 			 * new one drop it.
386 			 */
387 			next = next->next;
388 
389 			if (prev)
390 				prev->next = next;
391 			else
392 				fq->q.fragments = next;
393 
394 			fq->q.meat -= free_it->len;
395 			frag_kfree_skb(fq->q.net, free_it, NULL);
396 		}
397 	}
398 
399 	FRAG6_CB(skb)->offset = offset;
400 
401 	/* Insert this fragment in the chain of fragments. */
402 	skb->next = next;
403 	if (prev)
404 		prev->next = skb;
405 	else
406 		fq->q.fragments = skb;
407 
408 	dev = skb->dev;
409 	if (dev) {
410 		fq->iif = dev->ifindex;
411 		skb->dev = NULL;
412 	}
413 	fq->q.stamp = skb->tstamp;
414 	fq->q.meat += skb->len;
415 	atomic_add(skb->truesize, &fq->q.net->mem);
416 
417 	/* The first fragment.
418 	 * nhoffset is obtained from the first fragment, of course.
419 	 */
420 	if (offset == 0) {
421 		fq->nhoffset = nhoff;
422 		fq->q.last_in |= INET_FRAG_FIRST_IN;
423 	}
424 
425 	if (fq->q.last_in == (INET_FRAG_FIRST_IN | INET_FRAG_LAST_IN) &&
426 	    fq->q.meat == fq->q.len)
427 		return ip6_frag_reasm(fq, prev, dev);
428 
429 	write_lock(&ip6_frags.lock);
430 	list_move_tail(&fq->q.lru_list, &fq->q.net->lru_list);
431 	write_unlock(&ip6_frags.lock);
432 	return -1;
433 
434 err:
435 	IP6_INC_STATS(ip6_dst_idev(skb->dst), 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 sk_buff *fp, *head = fq->q.fragments;
453 	int    payload_len;
454 	unsigned int nhoff;
455 
456 	fq_kill(fq);
457 
458 	/* Make the one we just received the head. */
459 	if (prev) {
460 		head = prev->next;
461 		fp = skb_clone(head, GFP_ATOMIC);
462 
463 		if (!fp)
464 			goto out_oom;
465 
466 		fp->next = head->next;
467 		prev->next = fp;
468 
469 		skb_morph(head, fq->q.fragments);
470 		head->next = fq->q.fragments->next;
471 
472 		kfree_skb(fq->q.fragments);
473 		fq->q.fragments = head;
474 	}
475 
476 	BUG_TRAP(head != NULL);
477 	BUG_TRAP(FRAG6_CB(head)->offset == 0);
478 
479 	/* Unfragmented part is taken from the first segment. */
480 	payload_len = ((head->data - skb_network_header(head)) -
481 		       sizeof(struct ipv6hdr) + fq->q.len -
482 		       sizeof(struct frag_hdr));
483 	if (payload_len > IPV6_MAXPLEN)
484 		goto out_oversize;
485 
486 	/* Head of list must not be cloned. */
487 	if (skb_cloned(head) && pskb_expand_head(head, 0, 0, GFP_ATOMIC))
488 		goto out_oom;
489 
490 	/* If the first fragment is fragmented itself, we split
491 	 * it to two chunks: the first with data and paged part
492 	 * and the second, holding only fragments. */
493 	if (skb_shinfo(head)->frag_list) {
494 		struct sk_buff *clone;
495 		int i, plen = 0;
496 
497 		if ((clone = alloc_skb(0, GFP_ATOMIC)) == NULL)
498 			goto out_oom;
499 		clone->next = head->next;
500 		head->next = clone;
501 		skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list;
502 		skb_shinfo(head)->frag_list = NULL;
503 		for (i=0; i<skb_shinfo(head)->nr_frags; i++)
504 			plen += skb_shinfo(head)->frags[i].size;
505 		clone->len = clone->data_len = head->data_len - plen;
506 		head->data_len -= clone->len;
507 		head->len -= clone->len;
508 		clone->csum = 0;
509 		clone->ip_summed = head->ip_summed;
510 		atomic_add(clone->truesize, &fq->q.net->mem);
511 	}
512 
513 	/* We have to remove fragment header from datagram and to relocate
514 	 * header in order to calculate ICV correctly. */
515 	nhoff = fq->nhoffset;
516 	skb_network_header(head)[nhoff] = skb_transport_header(head)[0];
517 	memmove(head->head + sizeof(struct frag_hdr), head->head,
518 		(head->data - head->head) - sizeof(struct frag_hdr));
519 	head->mac_header += sizeof(struct frag_hdr);
520 	head->network_header += sizeof(struct frag_hdr);
521 
522 	skb_shinfo(head)->frag_list = head->next;
523 	skb_reset_transport_header(head);
524 	skb_push(head, head->data - skb_network_header(head));
525 	atomic_sub(head->truesize, &fq->q.net->mem);
526 
527 	for (fp=head->next; fp; fp = fp->next) {
528 		head->data_len += fp->len;
529 		head->len += fp->len;
530 		if (head->ip_summed != fp->ip_summed)
531 			head->ip_summed = CHECKSUM_NONE;
532 		else if (head->ip_summed == CHECKSUM_COMPLETE)
533 			head->csum = csum_add(head->csum, fp->csum);
534 		head->truesize += fp->truesize;
535 		atomic_sub(fp->truesize, &fq->q.net->mem);
536 	}
537 
538 	head->next = NULL;
539 	head->dev = dev;
540 	head->tstamp = fq->q.stamp;
541 	ipv6_hdr(head)->payload_len = htons(payload_len);
542 	IP6CB(head)->nhoff = nhoff;
543 
544 	/* Yes, and fold redundant checksum back. 8) */
545 	if (head->ip_summed == CHECKSUM_COMPLETE)
546 		head->csum = csum_partial(skb_network_header(head),
547 					  skb_network_header_len(head),
548 					  head->csum);
549 
550 	rcu_read_lock();
551 	IP6_INC_STATS_BH(__in6_dev_get(dev), IPSTATS_MIB_REASMOKS);
552 	rcu_read_unlock();
553 	fq->q.fragments = NULL;
554 	return 1;
555 
556 out_oversize:
557 	if (net_ratelimit())
558 		printk(KERN_DEBUG "ip6_frag_reasm: payload len = %d\n", payload_len);
559 	goto out_fail;
560 out_oom:
561 	if (net_ratelimit())
562 		printk(KERN_DEBUG "ip6_frag_reasm: no memory for reassembly\n");
563 out_fail:
564 	rcu_read_lock();
565 	IP6_INC_STATS_BH(__in6_dev_get(dev), IPSTATS_MIB_REASMFAILS);
566 	rcu_read_unlock();
567 	return -1;
568 }
569 
570 static int ipv6_frag_rcv(struct sk_buff *skb)
571 {
572 	struct frag_hdr *fhdr;
573 	struct frag_queue *fq;
574 	struct ipv6hdr *hdr = ipv6_hdr(skb);
575 	struct net *net;
576 
577 	IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_REASMREQDS);
578 
579 	/* Jumbo payload inhibits frag. header */
580 	if (hdr->payload_len==0) {
581 		IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_INHDRERRORS);
582 		icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
583 				  skb_network_header_len(skb));
584 		return -1;
585 	}
586 	if (!pskb_may_pull(skb, (skb_transport_offset(skb) +
587 				 sizeof(struct frag_hdr)))) {
588 		IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_INHDRERRORS);
589 		icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
590 				  skb_network_header_len(skb));
591 		return -1;
592 	}
593 
594 	hdr = ipv6_hdr(skb);
595 	fhdr = (struct frag_hdr *)skb_transport_header(skb);
596 
597 	if (!(fhdr->frag_off & htons(0xFFF9))) {
598 		/* It is not a fragmented frame */
599 		skb->transport_header += sizeof(struct frag_hdr);
600 		IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_REASMOKS);
601 
602 		IP6CB(skb)->nhoff = (u8 *)fhdr - skb_network_header(skb);
603 		return 1;
604 	}
605 
606 	net = dev_net(skb->dev);
607 	if (atomic_read(&net->ipv6.frags.mem) > net->ipv6.frags.high_thresh)
608 		ip6_evictor(net, ip6_dst_idev(skb->dst));
609 
610 	if ((fq = fq_find(net, fhdr->identification, &hdr->saddr, &hdr->daddr,
611 			  ip6_dst_idev(skb->dst))) != NULL) {
612 		int ret;
613 
614 		spin_lock(&fq->q.lock);
615 
616 		ret = ip6_frag_queue(fq, skb, fhdr, IP6CB(skb)->nhoff);
617 
618 		spin_unlock(&fq->q.lock);
619 		fq_put(fq);
620 		return ret;
621 	}
622 
623 	IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_REASMFAILS);
624 	kfree_skb(skb);
625 	return -1;
626 }
627 
628 static struct inet6_protocol frag_protocol =
629 {
630 	.handler	=	ipv6_frag_rcv,
631 	.flags		=	INET6_PROTO_NOPOLICY,
632 };
633 
634 #ifdef CONFIG_SYSCTL
635 static struct ctl_table ip6_frags_ctl_table[] = {
636 	{
637 		.ctl_name	= NET_IPV6_IP6FRAG_HIGH_THRESH,
638 		.procname	= "ip6frag_high_thresh",
639 		.data		= &init_net.ipv6.frags.high_thresh,
640 		.maxlen		= sizeof(int),
641 		.mode		= 0644,
642 		.proc_handler	= &proc_dointvec
643 	},
644 	{
645 		.ctl_name	= NET_IPV6_IP6FRAG_LOW_THRESH,
646 		.procname	= "ip6frag_low_thresh",
647 		.data		= &init_net.ipv6.frags.low_thresh,
648 		.maxlen		= sizeof(int),
649 		.mode		= 0644,
650 		.proc_handler	= &proc_dointvec
651 	},
652 	{
653 		.ctl_name	= NET_IPV6_IP6FRAG_TIME,
654 		.procname	= "ip6frag_time",
655 		.data		= &init_net.ipv6.frags.timeout,
656 		.maxlen		= sizeof(int),
657 		.mode		= 0644,
658 		.proc_handler	= &proc_dointvec_jiffies,
659 		.strategy	= &sysctl_jiffies,
660 	},
661 	{
662 		.ctl_name	= NET_IPV6_IP6FRAG_SECRET_INTERVAL,
663 		.procname	= "ip6frag_secret_interval",
664 		.data		= &ip6_frags.secret_interval,
665 		.maxlen		= sizeof(int),
666 		.mode		= 0644,
667 		.proc_handler	= &proc_dointvec_jiffies,
668 		.strategy	= &sysctl_jiffies
669 	},
670 	{ }
671 };
672 
673 static int ip6_frags_sysctl_register(struct net *net)
674 {
675 	struct ctl_table *table;
676 	struct ctl_table_header *hdr;
677 
678 	table = ip6_frags_ctl_table;
679 	if (net != &init_net) {
680 		table = kmemdup(table, sizeof(ip6_frags_ctl_table), GFP_KERNEL);
681 		if (table == NULL)
682 			goto err_alloc;
683 
684 		table[0].data = &net->ipv6.frags.high_thresh;
685 		table[1].data = &net->ipv6.frags.low_thresh;
686 		table[2].data = &net->ipv6.frags.timeout;
687 		table[3].mode &= ~0222;
688 	}
689 
690 	hdr = register_net_sysctl_table(net, net_ipv6_ctl_path, table);
691 	if (hdr == NULL)
692 		goto err_reg;
693 
694 	net->ipv6.sysctl.frags_hdr = hdr;
695 	return 0;
696 
697 err_reg:
698 	if (net != &init_net)
699 		kfree(table);
700 err_alloc:
701 	return -ENOMEM;
702 }
703 
704 static void ip6_frags_sysctl_unregister(struct net *net)
705 {
706 	struct ctl_table *table;
707 
708 	table = net->ipv6.sysctl.frags_hdr->ctl_table_arg;
709 	unregister_net_sysctl_table(net->ipv6.sysctl.frags_hdr);
710 	kfree(table);
711 }
712 #else
713 static inline int ip6_frags_sysctl_register(struct net *net)
714 {
715 	return 0;
716 }
717 
718 static inline void ip6_frags_sysctl_unregister(struct net *net)
719 {
720 }
721 #endif
722 
723 static int ipv6_frags_init_net(struct net *net)
724 {
725 	net->ipv6.frags.high_thresh = 256 * 1024;
726 	net->ipv6.frags.low_thresh = 192 * 1024;
727 	net->ipv6.frags.timeout = IPV6_FRAG_TIMEOUT;
728 
729 	inet_frags_init_net(&net->ipv6.frags);
730 
731 	return ip6_frags_sysctl_register(net);
732 }
733 
734 static void ipv6_frags_exit_net(struct net *net)
735 {
736 	ip6_frags_sysctl_unregister(net);
737 	inet_frags_exit_net(&net->ipv6.frags, &ip6_frags);
738 }
739 
740 static struct pernet_operations ip6_frags_ops = {
741 	.init = ipv6_frags_init_net,
742 	.exit = ipv6_frags_exit_net,
743 };
744 
745 int __init ipv6_frag_init(void)
746 {
747 	int ret;
748 
749 	ret = inet6_add_protocol(&frag_protocol, IPPROTO_FRAGMENT);
750 	if (ret)
751 		goto out;
752 
753 	register_pernet_subsys(&ip6_frags_ops);
754 
755 	ip6_frags.hashfn = ip6_hashfn;
756 	ip6_frags.constructor = ip6_frag_init;
757 	ip6_frags.destructor = NULL;
758 	ip6_frags.skb_free = NULL;
759 	ip6_frags.qsize = sizeof(struct frag_queue);
760 	ip6_frags.match = ip6_frag_match;
761 	ip6_frags.frag_expire = ip6_frag_expire;
762 	ip6_frags.secret_interval = 10 * 60 * HZ;
763 	inet_frags_init(&ip6_frags);
764 out:
765 	return ret;
766 }
767 
768 void ipv6_frag_exit(void)
769 {
770 	inet_frags_fini(&ip6_frags);
771 	unregister_pernet_subsys(&ip6_frags_ops);
772 	inet6_del_protocol(&frag_protocol, IPPROTO_FRAGMENT);
773 }
774