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1 /*
2  * IPv6 fragment reassembly for connection tracking
3  *
4  * Copyright (C)2004 USAGI/WIDE Project
5  *
6  * Author:
7  *	Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp>
8  *
9  * Based on: net/ipv6/reassembly.c
10  *
11  * This program is free software; you can redistribute it and/or
12  * modify it under the terms of the GNU General Public License
13  * as published by the Free Software Foundation; either version
14  * 2 of the License, or (at your option) any later version.
15  */
16 
17 #define pr_fmt(fmt) "IPv6-nf: " fmt
18 
19 #include <linux/errno.h>
20 #include <linux/types.h>
21 #include <linux/string.h>
22 #include <linux/socket.h>
23 #include <linux/sockios.h>
24 #include <linux/jiffies.h>
25 #include <linux/net.h>
26 #include <linux/list.h>
27 #include <linux/netdevice.h>
28 #include <linux/in6.h>
29 #include <linux/ipv6.h>
30 #include <linux/icmpv6.h>
31 #include <linux/random.h>
32 #include <linux/slab.h>
33 
34 #include <net/sock.h>
35 #include <net/snmp.h>
36 #include <net/inet_frag.h>
37 
38 #include <net/ipv6.h>
39 #include <net/protocol.h>
40 #include <net/transp_v6.h>
41 #include <net/rawv6.h>
42 #include <net/ndisc.h>
43 #include <net/addrconf.h>
44 #include <net/inet_ecn.h>
45 #include <net/netfilter/ipv6/nf_conntrack_ipv6.h>
46 #include <linux/sysctl.h>
47 #include <linux/netfilter.h>
48 #include <linux/netfilter_ipv6.h>
49 #include <linux/kernel.h>
50 #include <linux/module.h>
51 #include <net/netfilter/ipv6/nf_defrag_ipv6.h>
52 
53 
54 struct nf_ct_frag6_skb_cb
55 {
56 	struct inet6_skb_parm	h;
57 	int			offset;
58 	struct sk_buff		*orig;
59 };
60 
61 #define NFCT_FRAG6_CB(skb)	((struct nf_ct_frag6_skb_cb*)((skb)->cb))
62 
63 static struct inet_frags nf_frags;
64 
65 #ifdef CONFIG_SYSCTL
66 static struct ctl_table nf_ct_frag6_sysctl_table[] = {
67 	{
68 		.procname	= "nf_conntrack_frag6_timeout",
69 		.data		= &init_net.nf_frag.frags.timeout,
70 		.maxlen		= sizeof(unsigned int),
71 		.mode		= 0644,
72 		.proc_handler	= proc_dointvec_jiffies,
73 	},
74 	{
75 		.procname	= "nf_conntrack_frag6_low_thresh",
76 		.data		= &init_net.nf_frag.frags.low_thresh,
77 		.maxlen		= sizeof(unsigned int),
78 		.mode		= 0644,
79 		.proc_handler	= proc_dointvec,
80 	},
81 	{
82 		.procname	= "nf_conntrack_frag6_high_thresh",
83 		.data		= &init_net.nf_frag.frags.high_thresh,
84 		.maxlen		= sizeof(unsigned int),
85 		.mode		= 0644,
86 		.proc_handler	= proc_dointvec,
87 	},
88 	{ }
89 };
90 
nf_ct_frag6_sysctl_register(struct net * net)91 static int nf_ct_frag6_sysctl_register(struct net *net)
92 {
93 	struct ctl_table *table;
94 	struct ctl_table_header *hdr;
95 
96 	table = nf_ct_frag6_sysctl_table;
97 	if (!net_eq(net, &init_net)) {
98 		table = kmemdup(table, sizeof(nf_ct_frag6_sysctl_table),
99 				GFP_KERNEL);
100 		if (table == NULL)
101 			goto err_alloc;
102 
103 		table[0].data = &net->nf_frag.frags.timeout;
104 		table[1].data = &net->nf_frag.frags.low_thresh;
105 		table[2].data = &net->nf_frag.frags.high_thresh;
106 	}
107 
108 	hdr = register_net_sysctl(net, "net/netfilter", table);
109 	if (hdr == NULL)
110 		goto err_reg;
111 
112 	net->nf_frag.sysctl.frags_hdr = hdr;
113 	return 0;
114 
115 err_reg:
116 	if (!net_eq(net, &init_net))
117 		kfree(table);
118 err_alloc:
119 	return -ENOMEM;
120 }
121 
nf_ct_frags6_sysctl_unregister(struct net * net)122 static void __net_exit nf_ct_frags6_sysctl_unregister(struct net *net)
123 {
124 	struct ctl_table *table;
125 
126 	table = net->nf_frag.sysctl.frags_hdr->ctl_table_arg;
127 	unregister_net_sysctl_table(net->nf_frag.sysctl.frags_hdr);
128 	if (!net_eq(net, &init_net))
129 		kfree(table);
130 }
131 
132 #else
nf_ct_frag6_sysctl_register(struct net * net)133 static int nf_ct_frag6_sysctl_register(struct net *net)
134 {
135 	return 0;
136 }
nf_ct_frags6_sysctl_unregister(struct net * net)137 static void __net_exit nf_ct_frags6_sysctl_unregister(struct net *net)
138 {
139 }
140 #endif
141 
ip6_frag_ecn(const struct ipv6hdr * ipv6h)142 static inline u8 ip6_frag_ecn(const struct ipv6hdr *ipv6h)
143 {
144 	return 1 << (ipv6_get_dsfield(ipv6h) & INET_ECN_MASK);
145 }
146 
nf_hashfn(struct inet_frag_queue * q)147 static unsigned int nf_hashfn(struct inet_frag_queue *q)
148 {
149 	const struct frag_queue *nq;
150 
151 	nq = container_of(q, struct frag_queue, q);
152 	return inet6_hash_frag(nq->id, &nq->saddr, &nq->daddr, nf_frags.rnd);
153 }
154 
nf_skb_free(struct sk_buff * skb)155 static void nf_skb_free(struct sk_buff *skb)
156 {
157 	if (NFCT_FRAG6_CB(skb)->orig)
158 		kfree_skb(NFCT_FRAG6_CB(skb)->orig);
159 }
160 
nf_ct_frag6_expire(unsigned long data)161 static void nf_ct_frag6_expire(unsigned long data)
162 {
163 	struct frag_queue *fq;
164 	struct net *net;
165 
166 	fq = container_of((struct inet_frag_queue *)data, struct frag_queue, q);
167 	net = container_of(fq->q.net, struct net, nf_frag.frags);
168 
169 	ip6_expire_frag_queue(net, fq, &nf_frags);
170 }
171 
172 /* Creation primitives. */
fq_find(struct net * net,__be32 id,u32 user,struct in6_addr * src,struct in6_addr * dst,u8 ecn)173 static inline struct frag_queue *fq_find(struct net *net, __be32 id,
174 					 u32 user, struct in6_addr *src,
175 					 struct in6_addr *dst, u8 ecn)
176 {
177 	struct inet_frag_queue *q;
178 	struct ip6_create_arg arg;
179 	unsigned int hash;
180 
181 	arg.id = id;
182 	arg.user = user;
183 	arg.src = src;
184 	arg.dst = dst;
185 	arg.ecn = ecn;
186 
187 	read_lock_bh(&nf_frags.lock);
188 	hash = inet6_hash_frag(id, src, dst, nf_frags.rnd);
189 
190 	q = inet_frag_find(&net->nf_frag.frags, &nf_frags, &arg, hash);
191 	local_bh_enable();
192 	if (IS_ERR_OR_NULL(q)) {
193 		inet_frag_maybe_warn_overflow(q, pr_fmt());
194 		return NULL;
195 	}
196 	return container_of(q, struct frag_queue, q);
197 }
198 
199 
nf_ct_frag6_queue(struct frag_queue * fq,struct sk_buff * skb,const struct frag_hdr * fhdr,int nhoff)200 static int nf_ct_frag6_queue(struct frag_queue *fq, struct sk_buff *skb,
201 			     const struct frag_hdr *fhdr, int nhoff)
202 {
203 	struct sk_buff *prev, *next;
204 	unsigned int payload_len;
205 	int offset, end;
206 	u8 ecn;
207 
208 	if (fq->q.last_in & INET_FRAG_COMPLETE) {
209 		pr_debug("Already completed\n");
210 		goto err;
211 	}
212 
213 	payload_len = ntohs(ipv6_hdr(skb)->payload_len);
214 
215 	offset = ntohs(fhdr->frag_off) & ~0x7;
216 	end = offset + (payload_len -
217 			((u8 *)(fhdr + 1) - (u8 *)(ipv6_hdr(skb) + 1)));
218 
219 	if ((unsigned int)end > IPV6_MAXPLEN) {
220 		pr_debug("offset is too large.\n");
221 		return -1;
222 	}
223 
224 	ecn = ip6_frag_ecn(ipv6_hdr(skb));
225 
226 	if (skb->ip_summed == CHECKSUM_COMPLETE) {
227 		const unsigned char *nh = skb_network_header(skb);
228 		skb->csum = csum_sub(skb->csum,
229 				     csum_partial(nh, (u8 *)(fhdr + 1) - nh,
230 						  0));
231 	}
232 
233 	/* Is this the final fragment? */
234 	if (!(fhdr->frag_off & htons(IP6_MF))) {
235 		/* If we already have some bits beyond end
236 		 * or have different end, the segment is corrupted.
237 		 */
238 		if (end < fq->q.len ||
239 		    ((fq->q.last_in & INET_FRAG_LAST_IN) && end != fq->q.len)) {
240 			pr_debug("already received last fragment\n");
241 			goto err;
242 		}
243 		fq->q.last_in |= INET_FRAG_LAST_IN;
244 		fq->q.len = end;
245 	} else {
246 		/* Check if the fragment is rounded to 8 bytes.
247 		 * Required by the RFC.
248 		 */
249 		if (end & 0x7) {
250 			/* RFC2460 says always send parameter problem in
251 			 * this case. -DaveM
252 			 */
253 			pr_debug("end of fragment not rounded to 8 bytes.\n");
254 			return -1;
255 		}
256 		if (end > fq->q.len) {
257 			/* Some bits beyond end -> corruption. */
258 			if (fq->q.last_in & INET_FRAG_LAST_IN) {
259 				pr_debug("last packet already reached.\n");
260 				goto err;
261 			}
262 			fq->q.len = end;
263 		}
264 	}
265 
266 	if (end == offset)
267 		goto err;
268 
269 	/* Point into the IP datagram 'data' part. */
270 	if (!pskb_pull(skb, (u8 *) (fhdr + 1) - skb->data)) {
271 		pr_debug("queue: message is too short.\n");
272 		goto err;
273 	}
274 	if (pskb_trim_rcsum(skb, end - offset)) {
275 		pr_debug("Can't trim\n");
276 		goto err;
277 	}
278 
279 	/* Find out which fragments are in front and at the back of us
280 	 * in the chain of fragments so far.  We must know where to put
281 	 * this fragment, right?
282 	 */
283 	prev = fq->q.fragments_tail;
284 	if (!prev || NFCT_FRAG6_CB(prev)->offset < offset) {
285 		next = NULL;
286 		goto found;
287 	}
288 	prev = NULL;
289 	for (next = fq->q.fragments; next != NULL; next = next->next) {
290 		if (NFCT_FRAG6_CB(next)->offset >= offset)
291 			break;	/* bingo! */
292 		prev = next;
293 	}
294 
295 found:
296 	/* RFC5722, Section 4:
297 	 *                                  When reassembling an IPv6 datagram, if
298 	 *   one or more its constituent fragments is determined to be an
299 	 *   overlapping fragment, the entire datagram (and any constituent
300 	 *   fragments, including those not yet received) MUST be silently
301 	 *   discarded.
302 	 */
303 
304 	/* Check for overlap with preceding fragment. */
305 	if (prev &&
306 	    (NFCT_FRAG6_CB(prev)->offset + prev->len) > offset)
307 		goto discard_fq;
308 
309 	/* Look for overlap with succeeding segment. */
310 	if (next && NFCT_FRAG6_CB(next)->offset < end)
311 		goto discard_fq;
312 
313 	NFCT_FRAG6_CB(skb)->offset = offset;
314 
315 	/* Insert this fragment in the chain of fragments. */
316 	skb->next = next;
317 	if (!next)
318 		fq->q.fragments_tail = skb;
319 	if (prev)
320 		prev->next = skb;
321 	else
322 		fq->q.fragments = skb;
323 
324 	if (skb->dev) {
325 		fq->iif = skb->dev->ifindex;
326 		skb->dev = NULL;
327 	}
328 	fq->q.stamp = skb->tstamp;
329 	fq->q.meat += skb->len;
330 	fq->ecn |= ecn;
331 	if (payload_len > fq->q.max_size)
332 		fq->q.max_size = payload_len;
333 	add_frag_mem_limit(&fq->q, skb->truesize);
334 
335 	/* The first fragment.
336 	 * nhoffset is obtained from the first fragment, of course.
337 	 */
338 	if (offset == 0) {
339 		fq->nhoffset = nhoff;
340 		fq->q.last_in |= INET_FRAG_FIRST_IN;
341 	}
342 
343 	inet_frag_lru_move(&fq->q);
344 	return 0;
345 
346 discard_fq:
347 	inet_frag_kill(&fq->q, &nf_frags);
348 err:
349 	return -1;
350 }
351 
352 /*
353  *	Check if this packet is complete.
354  *	Returns NULL on failure by any reason, and pointer
355  *	to current nexthdr field in reassembled frame.
356  *
357  *	It is called with locked fq, and caller must check that
358  *	queue is eligible for reassembly i.e. it is not COMPLETE,
359  *	the last and the first frames arrived and all the bits are here.
360  */
361 static struct sk_buff *
nf_ct_frag6_reasm(struct frag_queue * fq,struct net_device * dev)362 nf_ct_frag6_reasm(struct frag_queue *fq, struct net_device *dev)
363 {
364 	struct sk_buff *fp, *op, *head = fq->q.fragments;
365 	int    payload_len;
366 	u8 ecn;
367 
368 	inet_frag_kill(&fq->q, &nf_frags);
369 
370 	WARN_ON(head == NULL);
371 	WARN_ON(NFCT_FRAG6_CB(head)->offset != 0);
372 
373 	ecn = ip_frag_ecn_table[fq->ecn];
374 	if (unlikely(ecn == 0xff))
375 		goto out_fail;
376 
377 	/* Unfragmented part is taken from the first segment. */
378 	payload_len = ((head->data - skb_network_header(head)) -
379 		       sizeof(struct ipv6hdr) + fq->q.len -
380 		       sizeof(struct frag_hdr));
381 	if (payload_len > IPV6_MAXPLEN) {
382 		pr_debug("payload len is too large.\n");
383 		goto out_oversize;
384 	}
385 
386 	/* Head of list must not be cloned. */
387 	if (skb_unclone(head, GFP_ATOMIC)) {
388 		pr_debug("skb is cloned but can't expand head");
389 		goto out_oom;
390 	}
391 
392 	/* If the first fragment is fragmented itself, we split
393 	 * it to two chunks: the first with data and paged part
394 	 * and the second, holding only fragments. */
395 	if (skb_has_frag_list(head)) {
396 		struct sk_buff *clone;
397 		int i, plen = 0;
398 
399 		clone = alloc_skb(0, GFP_ATOMIC);
400 		if (clone == NULL)
401 			goto out_oom;
402 
403 		clone->next = head->next;
404 		head->next = clone;
405 		skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list;
406 		skb_frag_list_init(head);
407 		for (i = 0; i < skb_shinfo(head)->nr_frags; i++)
408 			plen += skb_frag_size(&skb_shinfo(head)->frags[i]);
409 		clone->len = clone->data_len = head->data_len - plen;
410 		head->data_len -= clone->len;
411 		head->len -= clone->len;
412 		clone->csum = 0;
413 		clone->ip_summed = head->ip_summed;
414 
415 		NFCT_FRAG6_CB(clone)->orig = NULL;
416 		add_frag_mem_limit(&fq->q, clone->truesize);
417 	}
418 
419 	/* We have to remove fragment header from datagram and to relocate
420 	 * header in order to calculate ICV correctly. */
421 	skb_network_header(head)[fq->nhoffset] = skb_transport_header(head)[0];
422 	memmove(head->head + sizeof(struct frag_hdr), head->head,
423 		(head->data - head->head) - sizeof(struct frag_hdr));
424 	head->mac_header += sizeof(struct frag_hdr);
425 	head->network_header += sizeof(struct frag_hdr);
426 
427 	skb_shinfo(head)->frag_list = head->next;
428 	skb_reset_transport_header(head);
429 	skb_push(head, head->data - skb_network_header(head));
430 
431 	for (fp=head->next; fp; fp = fp->next) {
432 		head->data_len += fp->len;
433 		head->len += fp->len;
434 		if (head->ip_summed != fp->ip_summed)
435 			head->ip_summed = CHECKSUM_NONE;
436 		else if (head->ip_summed == CHECKSUM_COMPLETE)
437 			head->csum = csum_add(head->csum, fp->csum);
438 		head->truesize += fp->truesize;
439 	}
440 	sub_frag_mem_limit(&fq->q, head->truesize);
441 
442 	head->local_df = 1;
443 	head->next = NULL;
444 	head->dev = dev;
445 	head->tstamp = fq->q.stamp;
446 	ipv6_hdr(head)->payload_len = htons(payload_len);
447 	ipv6_change_dsfield(ipv6_hdr(head), 0xff, ecn);
448 	IP6CB(head)->frag_max_size = sizeof(struct ipv6hdr) + fq->q.max_size;
449 
450 	/* Yes, and fold redundant checksum back. 8) */
451 	if (head->ip_summed == CHECKSUM_COMPLETE)
452 		head->csum = csum_partial(skb_network_header(head),
453 					  skb_network_header_len(head),
454 					  head->csum);
455 
456 	fq->q.fragments = NULL;
457 	fq->q.fragments_tail = NULL;
458 
459 	/* all original skbs are linked into the NFCT_FRAG6_CB(head).orig */
460 	fp = skb_shinfo(head)->frag_list;
461 	if (fp && NFCT_FRAG6_CB(fp)->orig == NULL)
462 		/* at above code, head skb is divided into two skbs. */
463 		fp = fp->next;
464 
465 	op = NFCT_FRAG6_CB(head)->orig;
466 	for (; fp; fp = fp->next) {
467 		struct sk_buff *orig = NFCT_FRAG6_CB(fp)->orig;
468 
469 		op->next = orig;
470 		op = orig;
471 		NFCT_FRAG6_CB(fp)->orig = NULL;
472 	}
473 
474 	return head;
475 
476 out_oversize:
477 	net_dbg_ratelimited("nf_ct_frag6_reasm: payload len = %d\n",
478 			    payload_len);
479 	goto out_fail;
480 out_oom:
481 	net_dbg_ratelimited("nf_ct_frag6_reasm: no memory for reassembly\n");
482 out_fail:
483 	return NULL;
484 }
485 
486 /*
487  * find the header just before Fragment Header.
488  *
489  * if success return 0 and set ...
490  * (*prevhdrp): the value of "Next Header Field" in the header
491  *		just before Fragment Header.
492  * (*prevhoff): the offset of "Next Header Field" in the header
493  *		just before Fragment Header.
494  * (*fhoff)   : the offset of Fragment Header.
495  *
496  * Based on ipv6_skip_hdr() in net/ipv6/exthdr.c
497  *
498  */
499 static int
find_prev_fhdr(struct sk_buff * skb,u8 * prevhdrp,int * prevhoff,int * fhoff)500 find_prev_fhdr(struct sk_buff *skb, u8 *prevhdrp, int *prevhoff, int *fhoff)
501 {
502 	u8 nexthdr = ipv6_hdr(skb)->nexthdr;
503 	const int netoff = skb_network_offset(skb);
504 	u8 prev_nhoff = netoff + offsetof(struct ipv6hdr, nexthdr);
505 	int start = netoff + sizeof(struct ipv6hdr);
506 	int len = skb->len - start;
507 	u8 prevhdr = NEXTHDR_IPV6;
508 
509 	while (nexthdr != NEXTHDR_FRAGMENT) {
510 		struct ipv6_opt_hdr hdr;
511 		int hdrlen;
512 
513 		if (!ipv6_ext_hdr(nexthdr)) {
514 			return -1;
515 		}
516 		if (nexthdr == NEXTHDR_NONE) {
517 			pr_debug("next header is none\n");
518 			return -1;
519 		}
520 		if (len < (int)sizeof(struct ipv6_opt_hdr)) {
521 			pr_debug("too short\n");
522 			return -1;
523 		}
524 		if (skb_copy_bits(skb, start, &hdr, sizeof(hdr)))
525 			BUG();
526 		if (nexthdr == NEXTHDR_AUTH)
527 			hdrlen = (hdr.hdrlen+2)<<2;
528 		else
529 			hdrlen = ipv6_optlen(&hdr);
530 
531 		prevhdr = nexthdr;
532 		prev_nhoff = start;
533 
534 		nexthdr = hdr.nexthdr;
535 		len -= hdrlen;
536 		start += hdrlen;
537 	}
538 
539 	if (len < 0)
540 		return -1;
541 
542 	*prevhdrp = prevhdr;
543 	*prevhoff = prev_nhoff;
544 	*fhoff = start;
545 
546 	return 0;
547 }
548 
nf_ct_frag6_gather(struct sk_buff * skb,u32 user)549 struct sk_buff *nf_ct_frag6_gather(struct sk_buff *skb, u32 user)
550 {
551 	struct sk_buff *clone;
552 	struct net_device *dev = skb->dev;
553 	struct net *net = skb_dst(skb) ? dev_net(skb_dst(skb)->dev)
554 				       : dev_net(skb->dev);
555 	struct frag_hdr *fhdr;
556 	struct frag_queue *fq;
557 	struct ipv6hdr *hdr;
558 	int fhoff, nhoff;
559 	u8 prevhdr;
560 	struct sk_buff *ret_skb = NULL;
561 
562 	/* Jumbo payload inhibits frag. header */
563 	if (ipv6_hdr(skb)->payload_len == 0) {
564 		pr_debug("payload len = 0\n");
565 		return skb;
566 	}
567 
568 	if (find_prev_fhdr(skb, &prevhdr, &nhoff, &fhoff) < 0)
569 		return skb;
570 
571 	clone = skb_clone(skb, GFP_ATOMIC);
572 	if (clone == NULL) {
573 		pr_debug("Can't clone skb\n");
574 		return skb;
575 	}
576 
577 	NFCT_FRAG6_CB(clone)->orig = skb;
578 
579 	if (!pskb_may_pull(clone, fhoff + sizeof(*fhdr))) {
580 		pr_debug("message is too short.\n");
581 		goto ret_orig;
582 	}
583 
584 	skb_set_transport_header(clone, fhoff);
585 	hdr = ipv6_hdr(clone);
586 	fhdr = (struct frag_hdr *)skb_transport_header(clone);
587 
588 	local_bh_disable();
589 	inet_frag_evictor(&net->nf_frag.frags, &nf_frags, false);
590 	local_bh_enable();
591 
592 	fq = fq_find(net, fhdr->identification, user, &hdr->saddr, &hdr->daddr,
593 		     ip6_frag_ecn(hdr));
594 	if (fq == NULL) {
595 		pr_debug("Can't find and can't create new queue\n");
596 		goto ret_orig;
597 	}
598 
599 	spin_lock_bh(&fq->q.lock);
600 
601 	if (nf_ct_frag6_queue(fq, clone, fhdr, nhoff) < 0) {
602 		spin_unlock_bh(&fq->q.lock);
603 		pr_debug("Can't insert skb to queue\n");
604 		inet_frag_put(&fq->q, &nf_frags);
605 		goto ret_orig;
606 	}
607 
608 	if (fq->q.last_in == (INET_FRAG_FIRST_IN | INET_FRAG_LAST_IN) &&
609 	    fq->q.meat == fq->q.len) {
610 		ret_skb = nf_ct_frag6_reasm(fq, dev);
611 		if (ret_skb == NULL)
612 			pr_debug("Can't reassemble fragmented packets\n");
613 	}
614 	spin_unlock_bh(&fq->q.lock);
615 
616 	inet_frag_put(&fq->q, &nf_frags);
617 	return ret_skb;
618 
619 ret_orig:
620 	kfree_skb(clone);
621 	return skb;
622 }
623 
nf_ct_frag6_output(unsigned int hooknum,struct sk_buff * skb,struct net_device * in,struct net_device * out,int (* okfn)(struct sk_buff *))624 void nf_ct_frag6_output(unsigned int hooknum, struct sk_buff *skb,
625 			struct net_device *in, struct net_device *out,
626 			int (*okfn)(struct sk_buff *))
627 {
628 	struct sk_buff *s, *s2;
629 	unsigned int ret = 0;
630 
631 	for (s = NFCT_FRAG6_CB(skb)->orig; s;) {
632 		nf_conntrack_put_reasm(s->nfct_reasm);
633 		nf_conntrack_get_reasm(skb);
634 		s->nfct_reasm = skb;
635 
636 		s2 = s->next;
637 		s->next = NULL;
638 
639 		if (ret != -ECANCELED)
640 			ret = NF_HOOK_THRESH(NFPROTO_IPV6, hooknum, s,
641 					     in, out, okfn,
642 					     NF_IP6_PRI_CONNTRACK_DEFRAG + 1);
643 		else
644 			kfree_skb(s);
645 
646 		s = s2;
647 	}
648 	nf_conntrack_put_reasm(skb);
649 }
650 
nf_ct_net_init(struct net * net)651 static int nf_ct_net_init(struct net *net)
652 {
653 	net->nf_frag.frags.high_thresh = IPV6_FRAG_HIGH_THRESH;
654 	net->nf_frag.frags.low_thresh = IPV6_FRAG_LOW_THRESH;
655 	net->nf_frag.frags.timeout = IPV6_FRAG_TIMEOUT;
656 	inet_frags_init_net(&net->nf_frag.frags);
657 
658 	return nf_ct_frag6_sysctl_register(net);
659 }
660 
nf_ct_net_exit(struct net * net)661 static void nf_ct_net_exit(struct net *net)
662 {
663 	nf_ct_frags6_sysctl_unregister(net);
664 	inet_frags_exit_net(&net->nf_frag.frags, &nf_frags);
665 }
666 
667 static struct pernet_operations nf_ct_net_ops = {
668 	.init = nf_ct_net_init,
669 	.exit = nf_ct_net_exit,
670 };
671 
nf_ct_frag6_init(void)672 int nf_ct_frag6_init(void)
673 {
674 	int ret = 0;
675 
676 	nf_frags.hashfn = nf_hashfn;
677 	nf_frags.constructor = ip6_frag_init;
678 	nf_frags.destructor = NULL;
679 	nf_frags.skb_free = nf_skb_free;
680 	nf_frags.qsize = sizeof(struct frag_queue);
681 	nf_frags.match = ip6_frag_match;
682 	nf_frags.frag_expire = nf_ct_frag6_expire;
683 	nf_frags.secret_interval = 10 * 60 * HZ;
684 	inet_frags_init(&nf_frags);
685 
686 	ret = register_pernet_subsys(&nf_ct_net_ops);
687 	if (ret)
688 		inet_frags_fini(&nf_frags);
689 
690 	return ret;
691 }
692 
nf_ct_frag6_cleanup(void)693 void nf_ct_frag6_cleanup(void)
694 {
695 	unregister_pernet_subsys(&nf_ct_net_ops);
696 	inet_frags_fini(&nf_frags);
697 }
698