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TOMOYO Linux Cross Reference
Linux/net/ipv6/reassembly.c

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  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 
 30 #define pr_fmt(fmt) "IPv6: " fmt
 31 
 32 #include <linux/errno.h>
 33 #include <linux/types.h>
 34 #include <linux/string.h>
 35 #include <linux/socket.h>
 36 #include <linux/sockios.h>
 37 #include <linux/jiffies.h>
 38 #include <linux/net.h>
 39 #include <linux/list.h>
 40 #include <linux/netdevice.h>
 41 #include <linux/in6.h>
 42 #include <linux/ipv6.h>
 43 #include <linux/icmpv6.h>
 44 #include <linux/random.h>
 45 #include <linux/jhash.h>
 46 #include <linux/skbuff.h>
 47 #include <linux/slab.h>
 48 #include <linux/export.h>
 49 
 50 #include <net/sock.h>
 51 #include <net/snmp.h>
 52 
 53 #include <net/ipv6.h>
 54 #include <net/ip6_route.h>
 55 #include <net/protocol.h>
 56 #include <net/transp_v6.h>
 57 #include <net/rawv6.h>
 58 #include <net/ndisc.h>
 59 #include <net/addrconf.h>
 60 #include <net/inet_frag.h>
 61 #include <net/inet_ecn.h>
 62 
 63 static const char ip6_frag_cache_name[] = "ip6-frags";
 64 
 65 struct ip6frag_skb_cb {
 66         struct inet6_skb_parm   h;
 67         int                     offset;
 68 };
 69 
 70 #define FRAG6_CB(skb)   ((struct ip6frag_skb_cb *)((skb)->cb))
 71 
 72 static u8 ip6_frag_ecn(const struct ipv6hdr *ipv6h)
 73 {
 74         return 1 << (ipv6_get_dsfield(ipv6h) & INET_ECN_MASK);
 75 }
 76 
 77 static struct inet_frags ip6_frags;
 78 
 79 static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff *prev,
 80                           struct net_device *dev);
 81 
 82 /*
 83  * callers should be careful not to use the hash value outside the ipfrag_lock
 84  * as doing so could race with ipfrag_hash_rnd being recalculated.
 85  */
 86 static unsigned int inet6_hash_frag(__be32 id, const struct in6_addr *saddr,
 87                                     const struct in6_addr *daddr)
 88 {
 89         net_get_random_once(&ip6_frags.rnd, sizeof(ip6_frags.rnd));
 90         return jhash_3words(ipv6_addr_hash(saddr), ipv6_addr_hash(daddr),
 91                             (__force u32)id, ip6_frags.rnd);
 92 }
 93 
 94 static unsigned int ip6_hashfn(const struct inet_frag_queue *q)
 95 {
 96         const struct frag_queue *fq;
 97 
 98         fq = container_of(q, struct frag_queue, q);
 99         return inet6_hash_frag(fq->id, &fq->saddr, &fq->daddr);
100 }
101 
102 bool ip6_frag_match(const struct inet_frag_queue *q, const void *a)
103 {
104         const struct frag_queue *fq;
105         const struct ip6_create_arg *arg = a;
106 
107         fq = container_of(q, struct frag_queue, q);
108         return  fq->id == arg->id &&
109                 fq->user == arg->user &&
110                 ipv6_addr_equal(&fq->saddr, arg->src) &&
111                 ipv6_addr_equal(&fq->daddr, arg->dst) &&
112                 (arg->iif == fq->iif ||
113                  !(ipv6_addr_type(arg->dst) & (IPV6_ADDR_MULTICAST |
114                                                IPV6_ADDR_LINKLOCAL)));
115 }
116 EXPORT_SYMBOL(ip6_frag_match);
117 
118 void ip6_frag_init(struct inet_frag_queue *q, const void *a)
119 {
120         struct frag_queue *fq = container_of(q, struct frag_queue, q);
121         const struct ip6_create_arg *arg = a;
122 
123         fq->id = arg->id;
124         fq->user = arg->user;
125         fq->saddr = *arg->src;
126         fq->daddr = *arg->dst;
127         fq->ecn = arg->ecn;
128 }
129 EXPORT_SYMBOL(ip6_frag_init);
130 
131 void ip6_expire_frag_queue(struct net *net, struct frag_queue *fq,
132                            struct inet_frags *frags)
133 {
134         struct net_device *dev = NULL;
135 
136         spin_lock(&fq->q.lock);
137 
138         if (fq->q.flags & INET_FRAG_COMPLETE)
139                 goto out;
140 
141         inet_frag_kill(&fq->q, frags);
142 
143         rcu_read_lock();
144         dev = dev_get_by_index_rcu(net, fq->iif);
145         if (!dev)
146                 goto out_rcu_unlock;
147 
148         __IP6_INC_STATS(net, __in6_dev_get(dev), IPSTATS_MIB_REASMFAILS);
149 
150         if (inet_frag_evicting(&fq->q))
151                 goto out_rcu_unlock;
152 
153         __IP6_INC_STATS(net, __in6_dev_get(dev), IPSTATS_MIB_REASMTIMEOUT);
154 
155         /* Don't send error if the first segment did not arrive. */
156         if (!(fq->q.flags & INET_FRAG_FIRST_IN) || !fq->q.fragments)
157                 goto out_rcu_unlock;
158 
159         /* But use as source device on which LAST ARRIVED
160          * segment was received. And do not use fq->dev
161          * pointer directly, device might already disappeared.
162          */
163         fq->q.fragments->dev = dev;
164         icmpv6_send(fq->q.fragments, ICMPV6_TIME_EXCEED, ICMPV6_EXC_FRAGTIME, 0);
165 out_rcu_unlock:
166         rcu_read_unlock();
167 out:
168         spin_unlock(&fq->q.lock);
169         inet_frag_put(&fq->q, frags);
170 }
171 EXPORT_SYMBOL(ip6_expire_frag_queue);
172 
173 static void ip6_frag_expire(struct timer_list *t)
174 {
175         struct inet_frag_queue *frag = from_timer(frag, t, timer);
176         struct frag_queue *fq;
177         struct net *net;
178 
179         fq = container_of(frag, struct frag_queue, q);
180         net = container_of(fq->q.net, struct net, ipv6.frags);
181 
182         ip6_expire_frag_queue(net, fq, &ip6_frags);
183 }
184 
185 static struct frag_queue *
186 fq_find(struct net *net, __be32 id, const struct in6_addr *src,
187         const struct in6_addr *dst, int iif, u8 ecn)
188 {
189         struct inet_frag_queue *q;
190         struct ip6_create_arg arg;
191         unsigned int hash;
192 
193         arg.id = id;
194         arg.user = IP6_DEFRAG_LOCAL_DELIVER;
195         arg.src = src;
196         arg.dst = dst;
197         arg.iif = iif;
198         arg.ecn = ecn;
199 
200         hash = inet6_hash_frag(id, src, dst);
201 
202         q = inet_frag_find(&net->ipv6.frags, &ip6_frags, &arg, hash);
203         if (IS_ERR_OR_NULL(q)) {
204                 inet_frag_maybe_warn_overflow(q, pr_fmt());
205                 return NULL;
206         }
207         return container_of(q, struct frag_queue, q);
208 }
209 
210 static int ip6_frag_queue(struct frag_queue *fq, struct sk_buff *skb,
211                            struct frag_hdr *fhdr, int nhoff)
212 {
213         struct sk_buff *prev, *next;
214         struct net_device *dev;
215         int offset, end, fragsize;
216         struct net *net = dev_net(skb_dst(skb)->dev);
217         u8 ecn;
218 
219         if (fq->q.flags & INET_FRAG_COMPLETE)
220                 goto err;
221 
222         offset = ntohs(fhdr->frag_off) & ~0x7;
223         end = offset + (ntohs(ipv6_hdr(skb)->payload_len) -
224                         ((u8 *)(fhdr + 1) - (u8 *)(ipv6_hdr(skb) + 1)));
225 
226         if ((unsigned int)end > IPV6_MAXPLEN) {
227                 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
228                                 IPSTATS_MIB_INHDRERRORS);
229                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
230                                   ((u8 *)&fhdr->frag_off -
231                                    skb_network_header(skb)));
232                 return -1;
233         }
234 
235         ecn = ip6_frag_ecn(ipv6_hdr(skb));
236 
237         if (skb->ip_summed == CHECKSUM_COMPLETE) {
238                 const unsigned char *nh = skb_network_header(skb);
239                 skb->csum = csum_sub(skb->csum,
240                                      csum_partial(nh, (u8 *)(fhdr + 1) - nh,
241                                                   0));
242         }
243 
244         /* Is this the final fragment? */
245         if (!(fhdr->frag_off & htons(IP6_MF))) {
246                 /* If we already have some bits beyond end
247                  * or have different end, the segment is corrupted.
248                  */
249                 if (end < fq->q.len ||
250                     ((fq->q.flags & INET_FRAG_LAST_IN) && end != fq->q.len))
251                         goto err;
252                 fq->q.flags |= INET_FRAG_LAST_IN;
253                 fq->q.len = end;
254         } else {
255                 /* Check if the fragment is rounded to 8 bytes.
256                  * Required by the RFC.
257                  */
258                 if (end & 0x7) {
259                         /* RFC2460 says always send parameter problem in
260                          * this case. -DaveM
261                          */
262                         __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
263                                         IPSTATS_MIB_INHDRERRORS);
264                         icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
265                                           offsetof(struct ipv6hdr, payload_len));
266                         return -1;
267                 }
268                 if (end > fq->q.len) {
269                         /* Some bits beyond end -> corruption. */
270                         if (fq->q.flags & INET_FRAG_LAST_IN)
271                                 goto err;
272                         fq->q.len = end;
273                 }
274         }
275 
276         if (end == offset)
277                 goto err;
278 
279         /* Point into the IP datagram 'data' part. */
280         if (!pskb_pull(skb, (u8 *) (fhdr + 1) - skb->data))
281                 goto err;
282 
283         if (pskb_trim_rcsum(skb, end - offset))
284                 goto err;
285 
286         /* Find out which fragments are in front and at the back of us
287          * in the chain of fragments so far.  We must know where to put
288          * this fragment, right?
289          */
290         prev = fq->q.fragments_tail;
291         if (!prev || FRAG6_CB(prev)->offset < offset) {
292                 next = NULL;
293                 goto found;
294         }
295         prev = NULL;
296         for (next = fq->q.fragments; next != NULL; next = next->next) {
297                 if (FRAG6_CB(next)->offset >= offset)
298                         break;  /* bingo! */
299                 prev = next;
300         }
301 
302 found:
303         /* RFC5722, Section 4, amended by Errata ID : 3089
304          *                          When reassembling an IPv6 datagram, if
305          *   one or more its constituent fragments is determined to be an
306          *   overlapping fragment, the entire datagram (and any constituent
307          *   fragments) MUST be silently discarded.
308          */
309 
310         /* Check for overlap with preceding fragment. */
311         if (prev &&
312             (FRAG6_CB(prev)->offset + prev->len) > offset)
313                 goto discard_fq;
314 
315         /* Look for overlap with succeeding segment. */
316         if (next && FRAG6_CB(next)->offset < end)
317                 goto discard_fq;
318 
319         FRAG6_CB(skb)->offset = offset;
320 
321         /* Insert this fragment in the chain of fragments. */
322         skb->next = next;
323         if (!next)
324                 fq->q.fragments_tail = skb;
325         if (prev)
326                 prev->next = skb;
327         else
328                 fq->q.fragments = skb;
329 
330         dev = skb->dev;
331         if (dev) {
332                 fq->iif = dev->ifindex;
333                 skb->dev = NULL;
334         }
335         fq->q.stamp = skb->tstamp;
336         fq->q.meat += skb->len;
337         fq->ecn |= ecn;
338         add_frag_mem_limit(fq->q.net, skb->truesize);
339 
340         fragsize = -skb_network_offset(skb) + skb->len;
341         if (fragsize > fq->q.max_size)
342                 fq->q.max_size = fragsize;
343 
344         /* The first fragment.
345          * nhoffset is obtained from the first fragment, of course.
346          */
347         if (offset == 0) {
348                 fq->nhoffset = nhoff;
349                 fq->q.flags |= INET_FRAG_FIRST_IN;
350         }
351 
352         if (fq->q.flags == (INET_FRAG_FIRST_IN | INET_FRAG_LAST_IN) &&
353             fq->q.meat == fq->q.len) {
354                 int res;
355                 unsigned long orefdst = skb->_skb_refdst;
356 
357                 skb->_skb_refdst = 0UL;
358                 res = ip6_frag_reasm(fq, prev, dev);
359                 skb->_skb_refdst = orefdst;
360                 return res;
361         }
362 
363         skb_dst_drop(skb);
364         return -1;
365 
366 discard_fq:
367         inet_frag_kill(&fq->q, &ip6_frags);
368 err:
369         __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
370                         IPSTATS_MIB_REASMFAILS);
371         kfree_skb(skb);
372         return -1;
373 }
374 
375 /*
376  *      Check if this packet is complete.
377  *      Returns NULL on failure by any reason, and pointer
378  *      to current nexthdr field in reassembled frame.
379  *
380  *      It is called with locked fq, and caller must check that
381  *      queue is eligible for reassembly i.e. it is not COMPLETE,
382  *      the last and the first frames arrived and all the bits are here.
383  */
384 static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff *prev,
385                           struct net_device *dev)
386 {
387         struct net *net = container_of(fq->q.net, struct net, ipv6.frags);
388         struct sk_buff *fp, *head = fq->q.fragments;
389         int    payload_len;
390         unsigned int nhoff;
391         int sum_truesize;
392         u8 ecn;
393 
394         inet_frag_kill(&fq->q, &ip6_frags);
395 
396         ecn = ip_frag_ecn_table[fq->ecn];
397         if (unlikely(ecn == 0xff))
398                 goto out_fail;
399 
400         /* Make the one we just received the head. */
401         if (prev) {
402                 head = prev->next;
403                 fp = skb_clone(head, GFP_ATOMIC);
404 
405                 if (!fp)
406                         goto out_oom;
407 
408                 fp->next = head->next;
409                 if (!fp->next)
410                         fq->q.fragments_tail = fp;
411                 prev->next = fp;
412 
413                 skb_morph(head, fq->q.fragments);
414                 head->next = fq->q.fragments->next;
415 
416                 consume_skb(fq->q.fragments);
417                 fq->q.fragments = head;
418         }
419 
420         WARN_ON(head == NULL);
421         WARN_ON(FRAG6_CB(head)->offset != 0);
422 
423         /* Unfragmented part is taken from the first segment. */
424         payload_len = ((head->data - skb_network_header(head)) -
425                        sizeof(struct ipv6hdr) + fq->q.len -
426                        sizeof(struct frag_hdr));
427         if (payload_len > IPV6_MAXPLEN)
428                 goto out_oversize;
429 
430         /* Head of list must not be cloned. */
431         if (skb_unclone(head, GFP_ATOMIC))
432                 goto out_oom;
433 
434         /* If the first fragment is fragmented itself, we split
435          * it to two chunks: the first with data and paged part
436          * and the second, holding only fragments. */
437         if (skb_has_frag_list(head)) {
438                 struct sk_buff *clone;
439                 int i, plen = 0;
440 
441                 clone = alloc_skb(0, GFP_ATOMIC);
442                 if (!clone)
443                         goto out_oom;
444                 clone->next = head->next;
445                 head->next = clone;
446                 skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list;
447                 skb_frag_list_init(head);
448                 for (i = 0; i < skb_shinfo(head)->nr_frags; i++)
449                         plen += skb_frag_size(&skb_shinfo(head)->frags[i]);
450                 clone->len = clone->data_len = head->data_len - plen;
451                 head->data_len -= clone->len;
452                 head->len -= clone->len;
453                 clone->csum = 0;
454                 clone->ip_summed = head->ip_summed;
455                 add_frag_mem_limit(fq->q.net, clone->truesize);
456         }
457 
458         /* We have to remove fragment header from datagram and to relocate
459          * header in order to calculate ICV correctly. */
460         nhoff = fq->nhoffset;
461         skb_network_header(head)[nhoff] = skb_transport_header(head)[0];
462         memmove(head->head + sizeof(struct frag_hdr), head->head,
463                 (head->data - head->head) - sizeof(struct frag_hdr));
464         if (skb_mac_header_was_set(head))
465                 head->mac_header += sizeof(struct frag_hdr);
466         head->network_header += sizeof(struct frag_hdr);
467 
468         skb_reset_transport_header(head);
469         skb_push(head, head->data - skb_network_header(head));
470 
471         sum_truesize = head->truesize;
472         for (fp = head->next; fp;) {
473                 bool headstolen;
474                 int delta;
475                 struct sk_buff *next = fp->next;
476 
477                 sum_truesize += fp->truesize;
478                 if (head->ip_summed != fp->ip_summed)
479                         head->ip_summed = CHECKSUM_NONE;
480                 else if (head->ip_summed == CHECKSUM_COMPLETE)
481                         head->csum = csum_add(head->csum, fp->csum);
482 
483                 if (skb_try_coalesce(head, fp, &headstolen, &delta)) {
484                         kfree_skb_partial(fp, headstolen);
485                 } else {
486                         if (!skb_shinfo(head)->frag_list)
487                                 skb_shinfo(head)->frag_list = fp;
488                         head->data_len += fp->len;
489                         head->len += fp->len;
490                         head->truesize += fp->truesize;
491                 }
492                 fp = next;
493         }
494         sub_frag_mem_limit(fq->q.net, sum_truesize);
495 
496         head->next = NULL;
497         head->dev = dev;
498         head->tstamp = fq->q.stamp;
499         ipv6_hdr(head)->payload_len = htons(payload_len);
500         ipv6_change_dsfield(ipv6_hdr(head), 0xff, ecn);
501         IP6CB(head)->nhoff = nhoff;
502         IP6CB(head)->flags |= IP6SKB_FRAGMENTED;
503         IP6CB(head)->frag_max_size = fq->q.max_size;
504 
505         /* Yes, and fold redundant checksum back. 8) */
506         skb_postpush_rcsum(head, skb_network_header(head),
507                            skb_network_header_len(head));
508 
509         rcu_read_lock();
510         __IP6_INC_STATS(net, __in6_dev_get(dev), IPSTATS_MIB_REASMOKS);
511         rcu_read_unlock();
512         fq->q.fragments = NULL;
513         fq->q.fragments_tail = NULL;
514         return 1;
515 
516 out_oversize:
517         net_dbg_ratelimited("ip6_frag_reasm: payload len = %d\n", payload_len);
518         goto out_fail;
519 out_oom:
520         net_dbg_ratelimited("ip6_frag_reasm: no memory for reassembly\n");
521 out_fail:
522         rcu_read_lock();
523         __IP6_INC_STATS(net, __in6_dev_get(dev), IPSTATS_MIB_REASMFAILS);
524         rcu_read_unlock();
525         return -1;
526 }
527 
528 static int ipv6_frag_rcv(struct sk_buff *skb)
529 {
530         struct frag_hdr *fhdr;
531         struct frag_queue *fq;
532         const struct ipv6hdr *hdr = ipv6_hdr(skb);
533         struct net *net = dev_net(skb_dst(skb)->dev);
534 
535         if (IP6CB(skb)->flags & IP6SKB_FRAGMENTED)
536                 goto fail_hdr;
537 
538         __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_REASMREQDS);
539 
540         /* Jumbo payload inhibits frag. header */
541         if (hdr->payload_len == 0)
542                 goto fail_hdr;
543 
544         if (!pskb_may_pull(skb, (skb_transport_offset(skb) +
545                                  sizeof(struct frag_hdr))))
546                 goto fail_hdr;
547 
548         hdr = ipv6_hdr(skb);
549         fhdr = (struct frag_hdr *)skb_transport_header(skb);
550 
551         if (!(fhdr->frag_off & htons(0xFFF9))) {
552                 /* It is not a fragmented frame */
553                 skb->transport_header += sizeof(struct frag_hdr);
554                 __IP6_INC_STATS(net,
555                                 ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_REASMOKS);
556 
557                 IP6CB(skb)->nhoff = (u8 *)fhdr - skb_network_header(skb);
558                 IP6CB(skb)->flags |= IP6SKB_FRAGMENTED;
559                 return 1;
560         }
561 
562         fq = fq_find(net, fhdr->identification, &hdr->saddr, &hdr->daddr,
563                      skb->dev ? skb->dev->ifindex : 0, ip6_frag_ecn(hdr));
564         if (fq) {
565                 int ret;
566 
567                 spin_lock(&fq->q.lock);
568 
569                 ret = ip6_frag_queue(fq, skb, fhdr, IP6CB(skb)->nhoff);
570 
571                 spin_unlock(&fq->q.lock);
572                 inet_frag_put(&fq->q, &ip6_frags);
573                 return ret;
574         }
575 
576         __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_REASMFAILS);
577         kfree_skb(skb);
578         return -1;
579 
580 fail_hdr:
581         __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
582                         IPSTATS_MIB_INHDRERRORS);
583         icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, skb_network_header_len(skb));
584         return -1;
585 }
586 
587 static const struct inet6_protocol frag_protocol = {
588         .handler        =       ipv6_frag_rcv,
589         .flags          =       INET6_PROTO_NOPOLICY,
590 };
591 
592 #ifdef CONFIG_SYSCTL
593 static int zero;
594 
595 static struct ctl_table ip6_frags_ns_ctl_table[] = {
596         {
597                 .procname       = "ip6frag_high_thresh",
598                 .data           = &init_net.ipv6.frags.high_thresh,
599                 .maxlen         = sizeof(int),
600                 .mode           = 0644,
601                 .proc_handler   = proc_dointvec_minmax,
602                 .extra1         = &init_net.ipv6.frags.low_thresh
603         },
604         {
605                 .procname       = "ip6frag_low_thresh",
606                 .data           = &init_net.ipv6.frags.low_thresh,
607                 .maxlen         = sizeof(int),
608                 .mode           = 0644,
609                 .proc_handler   = proc_dointvec_minmax,
610                 .extra1         = &zero,
611                 .extra2         = &init_net.ipv6.frags.high_thresh
612         },
613         {
614                 .procname       = "ip6frag_time",
615                 .data           = &init_net.ipv6.frags.timeout,
616                 .maxlen         = sizeof(int),
617                 .mode           = 0644,
618                 .proc_handler   = proc_dointvec_jiffies,
619         },
620         { }
621 };
622 
623 /* secret interval has been deprecated */
624 static int ip6_frags_secret_interval_unused;
625 static struct ctl_table ip6_frags_ctl_table[] = {
626         {
627                 .procname       = "ip6frag_secret_interval",
628                 .data           = &ip6_frags_secret_interval_unused,
629                 .maxlen         = sizeof(int),
630                 .mode           = 0644,
631                 .proc_handler   = proc_dointvec_jiffies,
632         },
633         { }
634 };
635 
636 static int __net_init ip6_frags_ns_sysctl_register(struct net *net)
637 {
638         struct ctl_table *table;
639         struct ctl_table_header *hdr;
640 
641         table = ip6_frags_ns_ctl_table;
642         if (!net_eq(net, &init_net)) {
643                 table = kmemdup(table, sizeof(ip6_frags_ns_ctl_table), GFP_KERNEL);
644                 if (!table)
645                         goto err_alloc;
646 
647                 table[0].data = &net->ipv6.frags.high_thresh;
648                 table[0].extra1 = &net->ipv6.frags.low_thresh;
649                 table[0].extra2 = &init_net.ipv6.frags.high_thresh;
650                 table[1].data = &net->ipv6.frags.low_thresh;
651                 table[1].extra2 = &net->ipv6.frags.high_thresh;
652                 table[2].data = &net->ipv6.frags.timeout;
653 
654                 /* Don't export sysctls to unprivileged users */
655                 if (net->user_ns != &init_user_ns)
656                         table[0].procname = NULL;
657         }
658 
659         hdr = register_net_sysctl(net, "net/ipv6", table);
660         if (!hdr)
661                 goto err_reg;
662 
663         net->ipv6.sysctl.frags_hdr = hdr;
664         return 0;
665 
666 err_reg:
667         if (!net_eq(net, &init_net))
668                 kfree(table);
669 err_alloc:
670         return -ENOMEM;
671 }
672 
673 static void __net_exit ip6_frags_ns_sysctl_unregister(struct net *net)
674 {
675         struct ctl_table *table;
676 
677         table = net->ipv6.sysctl.frags_hdr->ctl_table_arg;
678         unregister_net_sysctl_table(net->ipv6.sysctl.frags_hdr);
679         if (!net_eq(net, &init_net))
680                 kfree(table);
681 }
682 
683 static struct ctl_table_header *ip6_ctl_header;
684 
685 static int ip6_frags_sysctl_register(void)
686 {
687         ip6_ctl_header = register_net_sysctl(&init_net, "net/ipv6",
688                         ip6_frags_ctl_table);
689         return ip6_ctl_header == NULL ? -ENOMEM : 0;
690 }
691 
692 static void ip6_frags_sysctl_unregister(void)
693 {
694         unregister_net_sysctl_table(ip6_ctl_header);
695 }
696 #else
697 static int ip6_frags_ns_sysctl_register(struct net *net)
698 {
699         return 0;
700 }
701 
702 static void ip6_frags_ns_sysctl_unregister(struct net *net)
703 {
704 }
705 
706 static int ip6_frags_sysctl_register(void)
707 {
708         return 0;
709 }
710 
711 static void ip6_frags_sysctl_unregister(void)
712 {
713 }
714 #endif
715 
716 static int __net_init ipv6_frags_init_net(struct net *net)
717 {
718         net->ipv6.frags.high_thresh = IPV6_FRAG_HIGH_THRESH;
719         net->ipv6.frags.low_thresh = IPV6_FRAG_LOW_THRESH;
720         net->ipv6.frags.timeout = IPV6_FRAG_TIMEOUT;
721 
722         inet_frags_init_net(&net->ipv6.frags);
723 
724         return ip6_frags_ns_sysctl_register(net);
725 }
726 
727 static void __net_exit ipv6_frags_exit_net(struct net *net)
728 {
729         ip6_frags_ns_sysctl_unregister(net);
730         inet_frags_exit_net(&net->ipv6.frags, &ip6_frags);
731 }
732 
733 static struct pernet_operations ip6_frags_ops = {
734         .init = ipv6_frags_init_net,
735         .exit = ipv6_frags_exit_net,
736 };
737 
738 int __init ipv6_frag_init(void)
739 {
740         int ret;
741 
742         ret = inet6_add_protocol(&frag_protocol, IPPROTO_FRAGMENT);
743         if (ret)
744                 goto out;
745 
746         ret = ip6_frags_sysctl_register();
747         if (ret)
748                 goto err_sysctl;
749 
750         ret = register_pernet_subsys(&ip6_frags_ops);
751         if (ret)
752                 goto err_pernet;
753 
754         ip6_frags.hashfn = ip6_hashfn;
755         ip6_frags.constructor = ip6_frag_init;
756         ip6_frags.destructor = NULL;
757         ip6_frags.qsize = sizeof(struct frag_queue);
758         ip6_frags.match = ip6_frag_match;
759         ip6_frags.frag_expire = ip6_frag_expire;
760         ip6_frags.frags_cache_name = ip6_frag_cache_name;
761         ret = inet_frags_init(&ip6_frags);
762         if (ret)
763                 goto err_pernet;
764 out:
765         return ret;
766 
767 err_pernet:
768         ip6_frags_sysctl_unregister();
769 err_sysctl:
770         inet6_del_protocol(&frag_protocol, IPPROTO_FRAGMENT);
771         goto out;
772 }
773 
774 void ipv6_frag_exit(void)
775 {
776         inet_frags_fini(&ip6_frags);
777         ip6_frags_sysctl_unregister();
778         unregister_pernet_subsys(&ip6_frags_ops);
779         inet6_del_protocol(&frag_protocol, IPPROTO_FRAGMENT);
780 }
781 

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