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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 struct ip6frag_skb_cb
 64 {
 65         struct inet6_skb_parm   h;
 66         int                     offset;
 67 };
 68 
 69 #define FRAG6_CB(skb)   ((struct ip6frag_skb_cb*)((skb)->cb))
 70 
 71 static inline u8 ip6_frag_ecn(const struct ipv6hdr *ipv6h)
 72 {
 73         return 1 << (ipv6_get_dsfield(ipv6h) & INET_ECN_MASK);
 74 }
 75 
 76 static struct inet_frags ip6_frags;
 77 
 78 static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff *prev,
 79                           struct net_device *dev);
 80 
 81 /*
 82  * callers should be careful not to use the hash value outside the ipfrag_lock
 83  * as doing so could race with ipfrag_hash_rnd being recalculated.
 84  */
 85 unsigned int inet6_hash_frag(__be32 id, const struct in6_addr *saddr,
 86                              const struct in6_addr *daddr, u32 rnd)
 87 {
 88         u32 c;
 89 
 90         c = jhash_3words(ipv6_addr_hash(saddr), ipv6_addr_hash(daddr),
 91                          (__force u32)id, rnd);
 92 
 93         return c & (INETFRAGS_HASHSZ - 1);
 94 }
 95 EXPORT_SYMBOL_GPL(inet6_hash_frag);
 96 
 97 static unsigned int ip6_hashfn(struct inet_frag_queue *q)
 98 {
 99         struct frag_queue *fq;
100 
101         fq = container_of(q, struct frag_queue, q);
102         return inet6_hash_frag(fq->id, &fq->saddr, &fq->daddr, ip6_frags.rnd);
103 }
104 
105 bool ip6_frag_match(struct inet_frag_queue *q, void *a)
106 {
107         struct frag_queue *fq;
108         struct ip6_create_arg *arg = a;
109 
110         fq = container_of(q, struct frag_queue, q);
111         return  fq->id == arg->id &&
112                 fq->user == arg->user &&
113                 ipv6_addr_equal(&fq->saddr, arg->src) &&
114                 ipv6_addr_equal(&fq->daddr, arg->dst);
115 }
116 EXPORT_SYMBOL(ip6_frag_match);
117 
118 void ip6_frag_init(struct inet_frag_queue *q, void *a)
119 {
120         struct frag_queue *fq = container_of(q, struct frag_queue, q);
121         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.last_in & 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_BH(net, __in6_dev_get(dev), IPSTATS_MIB_REASMTIMEOUT);
149         IP6_INC_STATS_BH(net, __in6_dev_get(dev), IPSTATS_MIB_REASMFAILS);
150 
151         /* Don't send error if the first segment did not arrive. */
152         if (!(fq->q.last_in & INET_FRAG_FIRST_IN) || !fq->q.fragments)
153                 goto out_rcu_unlock;
154 
155         /*
156            But use as source device on which LAST ARRIVED
157            segment was received. And do not use fq->dev
158            pointer directly, device might already disappeared.
159          */
160         fq->q.fragments->dev = dev;
161         icmpv6_send(fq->q.fragments, ICMPV6_TIME_EXCEED, ICMPV6_EXC_FRAGTIME, 0);
162 out_rcu_unlock:
163         rcu_read_unlock();
164 out:
165         spin_unlock(&fq->q.lock);
166         inet_frag_put(&fq->q, frags);
167 }
168 EXPORT_SYMBOL(ip6_expire_frag_queue);
169 
170 static void ip6_frag_expire(unsigned long data)
171 {
172         struct frag_queue *fq;
173         struct net *net;
174 
175         fq = container_of((struct inet_frag_queue *)data, struct frag_queue, q);
176         net = container_of(fq->q.net, struct net, ipv6.frags);
177 
178         ip6_expire_frag_queue(net, fq, &ip6_frags);
179 }
180 
181 static __inline__ struct frag_queue *
182 fq_find(struct net *net, __be32 id, const struct in6_addr *src,
183         const struct in6_addr *dst, u8 ecn)
184 {
185         struct inet_frag_queue *q;
186         struct ip6_create_arg arg;
187         unsigned int hash;
188 
189         arg.id = id;
190         arg.user = IP6_DEFRAG_LOCAL_DELIVER;
191         arg.src = src;
192         arg.dst = dst;
193         arg.ecn = ecn;
194 
195         read_lock(&ip6_frags.lock);
196         hash = inet6_hash_frag(id, src, dst, ip6_frags.rnd);
197 
198         q = inet_frag_find(&net->ipv6.frags, &ip6_frags, &arg, hash);
199         if (IS_ERR_OR_NULL(q)) {
200                 inet_frag_maybe_warn_overflow(q, pr_fmt());
201                 return NULL;
202         }
203         return container_of(q, struct frag_queue, q);
204 }
205 
206 static int ip6_frag_queue(struct frag_queue *fq, struct sk_buff *skb,
207                            struct frag_hdr *fhdr, int nhoff)
208 {
209         struct sk_buff *prev, *next;
210         struct net_device *dev;
211         int offset, end;
212         struct net *net = dev_net(skb_dst(skb)->dev);
213         u8 ecn;
214 
215         if (fq->q.last_in & INET_FRAG_COMPLETE)
216                 goto err;
217 
218         offset = ntohs(fhdr->frag_off) & ~0x7;
219         end = offset + (ntohs(ipv6_hdr(skb)->payload_len) -
220                         ((u8 *)(fhdr + 1) - (u8 *)(ipv6_hdr(skb) + 1)));
221 
222         if ((unsigned int)end > IPV6_MAXPLEN) {
223                 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
224                                  IPSTATS_MIB_INHDRERRORS);
225                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
226                                   ((u8 *)&fhdr->frag_off -
227                                    skb_network_header(skb)));
228                 return -1;
229         }
230 
231         ecn = ip6_frag_ecn(ipv6_hdr(skb));
232 
233         if (skb->ip_summed == CHECKSUM_COMPLETE) {
234                 const unsigned char *nh = skb_network_header(skb);
235                 skb->csum = csum_sub(skb->csum,
236                                      csum_partial(nh, (u8 *)(fhdr + 1) - nh,
237                                                   0));
238         }
239 
240         /* Is this the final fragment? */
241         if (!(fhdr->frag_off & htons(IP6_MF))) {
242                 /* If we already have some bits beyond end
243                  * or have different end, the segment is corrupted.
244                  */
245                 if (end < fq->q.len ||
246                     ((fq->q.last_in & INET_FRAG_LAST_IN) && end != fq->q.len))
247                         goto err;
248                 fq->q.last_in |= INET_FRAG_LAST_IN;
249                 fq->q.len = end;
250         } else {
251                 /* Check if the fragment is rounded to 8 bytes.
252                  * Required by the RFC.
253                  */
254                 if (end & 0x7) {
255                         /* RFC2460 says always send parameter problem in
256                          * this case. -DaveM
257                          */
258                         IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
259                                          IPSTATS_MIB_INHDRERRORS);
260                         icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
261                                           offsetof(struct ipv6hdr, payload_len));
262                         return -1;
263                 }
264                 if (end > fq->q.len) {
265                         /* Some bits beyond end -> corruption. */
266                         if (fq->q.last_in & INET_FRAG_LAST_IN)
267                                 goto err;
268                         fq->q.len = end;
269                 }
270         }
271 
272         if (end == offset)
273                 goto err;
274 
275         /* Point into the IP datagram 'data' part. */
276         if (!pskb_pull(skb, (u8 *) (fhdr + 1) - skb->data))
277                 goto err;
278 
279         if (pskb_trim_rcsum(skb, end - offset))
280                 goto err;
281 
282         /* Find out which fragments are in front and at the back of us
283          * in the chain of fragments so far.  We must know where to put
284          * this fragment, right?
285          */
286         prev = fq->q.fragments_tail;
287         if (!prev || FRAG6_CB(prev)->offset < offset) {
288                 next = NULL;
289                 goto found;
290         }
291         prev = NULL;
292         for(next = fq->q.fragments; next != NULL; next = next->next) {
293                 if (FRAG6_CB(next)->offset >= offset)
294                         break;  /* bingo! */
295                 prev = next;
296         }
297 
298 found:
299         /* RFC5722, Section 4, amended by Errata ID : 3089
300          *                          When reassembling an IPv6 datagram, if
301          *   one or more its constituent fragments is determined to be an
302          *   overlapping fragment, the entire datagram (and any constituent
303          *   fragments) MUST be silently discarded.
304          */
305 
306         /* Check for overlap with preceding fragment. */
307         if (prev &&
308             (FRAG6_CB(prev)->offset + prev->len) > offset)
309                 goto discard_fq;
310 
311         /* Look for overlap with succeeding segment. */
312         if (next && FRAG6_CB(next)->offset < end)
313                 goto discard_fq;
314 
315         FRAG6_CB(skb)->offset = offset;
316 
317         /* Insert this fragment in the chain of fragments. */
318         skb->next = next;
319         if (!next)
320                 fq->q.fragments_tail = skb;
321         if (prev)
322                 prev->next = skb;
323         else
324                 fq->q.fragments = skb;
325 
326         dev = skb->dev;
327         if (dev) {
328                 fq->iif = dev->ifindex;
329                 skb->dev = NULL;
330         }
331         fq->q.stamp = skb->tstamp;
332         fq->q.meat += skb->len;
333         fq->ecn |= ecn;
334         add_frag_mem_limit(&fq->q, skb->truesize);
335 
336         /* The first fragment.
337          * nhoffset is obtained from the first fragment, of course.
338          */
339         if (offset == 0) {
340                 fq->nhoffset = nhoff;
341                 fq->q.last_in |= INET_FRAG_FIRST_IN;
342         }
343 
344         if (fq->q.last_in == (INET_FRAG_FIRST_IN | INET_FRAG_LAST_IN) &&
345             fq->q.meat == fq->q.len) {
346                 int res;
347                 unsigned long orefdst = skb->_skb_refdst;
348 
349                 skb->_skb_refdst = 0UL;
350                 res = ip6_frag_reasm(fq, prev, dev);
351                 skb->_skb_refdst = orefdst;
352                 return res;
353         }
354 
355         skb_dst_drop(skb);
356         inet_frag_lru_move(&fq->q);
357         return -1;
358 
359 discard_fq:
360         inet_frag_kill(&fq->q, &ip6_frags);
361 err:
362         IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
363                       IPSTATS_MIB_REASMFAILS);
364         kfree_skb(skb);
365         return -1;
366 }
367 
368 /*
369  *      Check if this packet is complete.
370  *      Returns NULL on failure by any reason, and pointer
371  *      to current nexthdr field in reassembled frame.
372  *
373  *      It is called with locked fq, and caller must check that
374  *      queue is eligible for reassembly i.e. it is not COMPLETE,
375  *      the last and the first frames arrived and all the bits are here.
376  */
377 static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff *prev,
378                           struct net_device *dev)
379 {
380         struct net *net = container_of(fq->q.net, struct net, ipv6.frags);
381         struct sk_buff *fp, *head = fq->q.fragments;
382         int    payload_len;
383         unsigned int nhoff;
384         int sum_truesize;
385         u8 ecn;
386 
387         inet_frag_kill(&fq->q, &ip6_frags);
388 
389         ecn = ip_frag_ecn_table[fq->ecn];
390         if (unlikely(ecn == 0xff))
391                 goto out_fail;
392 
393         /* Make the one we just received the head. */
394         if (prev) {
395                 head = prev->next;
396                 fp = skb_clone(head, GFP_ATOMIC);
397 
398                 if (!fp)
399                         goto out_oom;
400 
401                 fp->next = head->next;
402                 if (!fp->next)
403                         fq->q.fragments_tail = fp;
404                 prev->next = fp;
405 
406                 skb_morph(head, fq->q.fragments);
407                 head->next = fq->q.fragments->next;
408 
409                 consume_skb(fq->q.fragments);
410                 fq->q.fragments = head;
411         }
412 
413         WARN_ON(head == NULL);
414         WARN_ON(FRAG6_CB(head)->offset != 0);
415 
416         /* Unfragmented part is taken from the first segment. */
417         payload_len = ((head->data - skb_network_header(head)) -
418                        sizeof(struct ipv6hdr) + fq->q.len -
419                        sizeof(struct frag_hdr));
420         if (payload_len > IPV6_MAXPLEN)
421                 goto out_oversize;
422 
423         /* Head of list must not be cloned. */
424         if (skb_unclone(head, GFP_ATOMIC))
425                 goto out_oom;
426 
427         /* If the first fragment is fragmented itself, we split
428          * it to two chunks: the first with data and paged part
429          * and the second, holding only fragments. */
430         if (skb_has_frag_list(head)) {
431                 struct sk_buff *clone;
432                 int i, plen = 0;
433 
434                 if ((clone = alloc_skb(0, GFP_ATOMIC)) == NULL)
435                         goto out_oom;
436                 clone->next = head->next;
437                 head->next = clone;
438                 skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list;
439                 skb_frag_list_init(head);
440                 for (i = 0; i < skb_shinfo(head)->nr_frags; i++)
441                         plen += skb_frag_size(&skb_shinfo(head)->frags[i]);
442                 clone->len = clone->data_len = head->data_len - plen;
443                 head->data_len -= clone->len;
444                 head->len -= clone->len;
445                 clone->csum = 0;
446                 clone->ip_summed = head->ip_summed;
447                 add_frag_mem_limit(&fq->q, clone->truesize);
448         }
449 
450         /* We have to remove fragment header from datagram and to relocate
451          * header in order to calculate ICV correctly. */
452         nhoff = fq->nhoffset;
453         skb_network_header(head)[nhoff] = skb_transport_header(head)[0];
454         memmove(head->head + sizeof(struct frag_hdr), head->head,
455                 (head->data - head->head) - sizeof(struct frag_hdr));
456         head->mac_header += sizeof(struct frag_hdr);
457         head->network_header += sizeof(struct frag_hdr);
458 
459         skb_reset_transport_header(head);
460         skb_push(head, head->data - skb_network_header(head));
461 
462         sum_truesize = head->truesize;
463         for (fp = head->next; fp;) {
464                 bool headstolen;
465                 int delta;
466                 struct sk_buff *next = fp->next;
467 
468                 sum_truesize += fp->truesize;
469                 if (head->ip_summed != fp->ip_summed)
470                         head->ip_summed = CHECKSUM_NONE;
471                 else if (head->ip_summed == CHECKSUM_COMPLETE)
472                         head->csum = csum_add(head->csum, fp->csum);
473 
474                 if (skb_try_coalesce(head, fp, &headstolen, &delta)) {
475                         kfree_skb_partial(fp, headstolen);
476                 } else {
477                         if (!skb_shinfo(head)->frag_list)
478                                 skb_shinfo(head)->frag_list = fp;
479                         head->data_len += fp->len;
480                         head->len += fp->len;
481                         head->truesize += fp->truesize;
482                 }
483                 fp = next;
484         }
485         sub_frag_mem_limit(&fq->q, sum_truesize);
486 
487         head->next = NULL;
488         head->dev = dev;
489         head->tstamp = fq->q.stamp;
490         ipv6_hdr(head)->payload_len = htons(payload_len);
491         ipv6_change_dsfield(ipv6_hdr(head), 0xff, ecn);
492         IP6CB(head)->nhoff = nhoff;
493         IP6CB(head)->flags |= IP6SKB_FRAGMENTED;
494 
495         /* Yes, and fold redundant checksum back. 8) */
496         if (head->ip_summed == CHECKSUM_COMPLETE)
497                 head->csum = csum_partial(skb_network_header(head),
498                                           skb_network_header_len(head),
499                                           head->csum);
500 
501         rcu_read_lock();
502         IP6_INC_STATS_BH(net, __in6_dev_get(dev), IPSTATS_MIB_REASMOKS);
503         rcu_read_unlock();
504         fq->q.fragments = NULL;
505         fq->q.fragments_tail = NULL;
506         return 1;
507 
508 out_oversize:
509         net_dbg_ratelimited("ip6_frag_reasm: payload len = %d\n", payload_len);
510         goto out_fail;
511 out_oom:
512         net_dbg_ratelimited("ip6_frag_reasm: no memory for reassembly\n");
513 out_fail:
514         rcu_read_lock();
515         IP6_INC_STATS_BH(net, __in6_dev_get(dev), IPSTATS_MIB_REASMFAILS);
516         rcu_read_unlock();
517         return -1;
518 }
519 
520 static int ipv6_frag_rcv(struct sk_buff *skb)
521 {
522         struct frag_hdr *fhdr;
523         struct frag_queue *fq;
524         const struct ipv6hdr *hdr = ipv6_hdr(skb);
525         struct net *net = dev_net(skb_dst(skb)->dev);
526         int evicted;
527 
528         if (IP6CB(skb)->flags & IP6SKB_FRAGMENTED)
529                 goto fail_hdr;
530 
531         IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_REASMREQDS);
532 
533         /* Jumbo payload inhibits frag. header */
534         if (hdr->payload_len==0)
535                 goto fail_hdr;
536 
537         if (!pskb_may_pull(skb, (skb_transport_offset(skb) +
538                                  sizeof(struct frag_hdr))))
539                 goto fail_hdr;
540 
541         hdr = ipv6_hdr(skb);
542         fhdr = (struct frag_hdr *)skb_transport_header(skb);
543 
544         if (!(fhdr->frag_off & htons(0xFFF9))) {
545                 /* It is not a fragmented frame */
546                 skb->transport_header += sizeof(struct frag_hdr);
547                 IP6_INC_STATS_BH(net,
548                                  ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_REASMOKS);
549 
550                 IP6CB(skb)->nhoff = (u8 *)fhdr - skb_network_header(skb);
551                 IP6CB(skb)->flags |= IP6SKB_FRAGMENTED;
552                 return 1;
553         }
554 
555         evicted = inet_frag_evictor(&net->ipv6.frags, &ip6_frags, false);
556         if (evicted)
557                 IP6_ADD_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
558                                  IPSTATS_MIB_REASMFAILS, evicted);
559 
560         fq = fq_find(net, fhdr->identification, &hdr->saddr, &hdr->daddr,
561                      ip6_frag_ecn(hdr));
562         if (fq != NULL) {
563                 int ret;
564 
565                 spin_lock(&fq->q.lock);
566 
567                 ret = ip6_frag_queue(fq, skb, fhdr, IP6CB(skb)->nhoff);
568 
569                 spin_unlock(&fq->q.lock);
570                 inet_frag_put(&fq->q, &ip6_frags);
571                 return ret;
572         }
573 
574         IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_REASMFAILS);
575         kfree_skb(skb);
576         return -1;
577 
578 fail_hdr:
579         IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_INHDRERRORS);
580         icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, skb_network_header_len(skb));
581         return -1;
582 }
583 
584 static const struct inet6_protocol frag_protocol =
585 {
586         .handler        =       ipv6_frag_rcv,
587         .flags          =       INET6_PROTO_NOPOLICY,
588 };
589 
590 #ifdef CONFIG_SYSCTL
591 static struct ctl_table ip6_frags_ns_ctl_table[] = {
592         {
593                 .procname       = "ip6frag_high_thresh",
594                 .data           = &init_net.ipv6.frags.high_thresh,
595                 .maxlen         = sizeof(int),
596                 .mode           = 0644,
597                 .proc_handler   = proc_dointvec
598         },
599         {
600                 .procname       = "ip6frag_low_thresh",
601                 .data           = &init_net.ipv6.frags.low_thresh,
602                 .maxlen         = sizeof(int),
603                 .mode           = 0644,
604                 .proc_handler   = proc_dointvec
605         },
606         {
607                 .procname       = "ip6frag_time",
608                 .data           = &init_net.ipv6.frags.timeout,
609                 .maxlen         = sizeof(int),
610                 .mode           = 0644,
611                 .proc_handler   = proc_dointvec_jiffies,
612         },
613         { }
614 };
615 
616 static struct ctl_table ip6_frags_ctl_table[] = {
617         {
618                 .procname       = "ip6frag_secret_interval",
619                 .data           = &ip6_frags.secret_interval,
620                 .maxlen         = sizeof(int),
621                 .mode           = 0644,
622                 .proc_handler   = proc_dointvec_jiffies,
623         },
624         { }
625 };
626 
627 static int __net_init ip6_frags_ns_sysctl_register(struct net *net)
628 {
629         struct ctl_table *table;
630         struct ctl_table_header *hdr;
631 
632         table = ip6_frags_ns_ctl_table;
633         if (!net_eq(net, &init_net)) {
634                 table = kmemdup(table, sizeof(ip6_frags_ns_ctl_table), GFP_KERNEL);
635                 if (table == NULL)
636                         goto err_alloc;
637 
638                 table[0].data = &net->ipv6.frags.high_thresh;
639                 table[1].data = &net->ipv6.frags.low_thresh;
640                 table[2].data = &net->ipv6.frags.timeout;
641 
642                 /* Don't export sysctls to unprivileged users */
643                 if (net->user_ns != &init_user_ns)
644                         table[0].procname = NULL;
645         }
646 
647         hdr = register_net_sysctl(net, "net/ipv6", table);
648         if (hdr == NULL)
649                 goto err_reg;
650 
651         net->ipv6.sysctl.frags_hdr = hdr;
652         return 0;
653 
654 err_reg:
655         if (!net_eq(net, &init_net))
656                 kfree(table);
657 err_alloc:
658         return -ENOMEM;
659 }
660 
661 static void __net_exit ip6_frags_ns_sysctl_unregister(struct net *net)
662 {
663         struct ctl_table *table;
664 
665         table = net->ipv6.sysctl.frags_hdr->ctl_table_arg;
666         unregister_net_sysctl_table(net->ipv6.sysctl.frags_hdr);
667         if (!net_eq(net, &init_net))
668                 kfree(table);
669 }
670 
671 static struct ctl_table_header *ip6_ctl_header;
672 
673 static int ip6_frags_sysctl_register(void)
674 {
675         ip6_ctl_header = register_net_sysctl(&init_net, "net/ipv6",
676                         ip6_frags_ctl_table);
677         return ip6_ctl_header == NULL ? -ENOMEM : 0;
678 }
679 
680 static void ip6_frags_sysctl_unregister(void)
681 {
682         unregister_net_sysctl_table(ip6_ctl_header);
683 }
684 #else
685 static inline int ip6_frags_ns_sysctl_register(struct net *net)
686 {
687         return 0;
688 }
689 
690 static inline void ip6_frags_ns_sysctl_unregister(struct net *net)
691 {
692 }
693 
694 static inline int ip6_frags_sysctl_register(void)
695 {
696         return 0;
697 }
698 
699 static inline void ip6_frags_sysctl_unregister(void)
700 {
701 }
702 #endif
703 
704 static int __net_init ipv6_frags_init_net(struct net *net)
705 {
706         net->ipv6.frags.high_thresh = IPV6_FRAG_HIGH_THRESH;
707         net->ipv6.frags.low_thresh = IPV6_FRAG_LOW_THRESH;
708         net->ipv6.frags.timeout = IPV6_FRAG_TIMEOUT;
709 
710         inet_frags_init_net(&net->ipv6.frags);
711 
712         return ip6_frags_ns_sysctl_register(net);
713 }
714 
715 static void __net_exit ipv6_frags_exit_net(struct net *net)
716 {
717         ip6_frags_ns_sysctl_unregister(net);
718         inet_frags_exit_net(&net->ipv6.frags, &ip6_frags);
719 }
720 
721 static struct pernet_operations ip6_frags_ops = {
722         .init = ipv6_frags_init_net,
723         .exit = ipv6_frags_exit_net,
724 };
725 
726 int __init ipv6_frag_init(void)
727 {
728         int ret;
729 
730         ret = inet6_add_protocol(&frag_protocol, IPPROTO_FRAGMENT);
731         if (ret)
732                 goto out;
733 
734         ret = ip6_frags_sysctl_register();
735         if (ret)
736                 goto err_sysctl;
737 
738         ret = register_pernet_subsys(&ip6_frags_ops);
739         if (ret)
740                 goto err_pernet;
741 
742         ip6_frags.hashfn = ip6_hashfn;
743         ip6_frags.constructor = ip6_frag_init;
744         ip6_frags.destructor = NULL;
745         ip6_frags.skb_free = NULL;
746         ip6_frags.qsize = sizeof(struct frag_queue);
747         ip6_frags.match = ip6_frag_match;
748         ip6_frags.frag_expire = ip6_frag_expire;
749         ip6_frags.secret_interval = 10 * 60 * HZ;
750         inet_frags_init(&ip6_frags);
751 out:
752         return ret;
753 
754 err_pernet:
755         ip6_frags_sysctl_unregister();
756 err_sysctl:
757         inet6_del_protocol(&frag_protocol, IPPROTO_FRAGMENT);
758         goto out;
759 }
760 
761 void ipv6_frag_exit(void)
762 {
763         inet_frags_fini(&ip6_frags);
764         ip6_frags_sysctl_unregister();
765         unregister_pernet_subsys(&ip6_frags_ops);
766         inet6_del_protocol(&frag_protocol, IPPROTO_FRAGMENT);
767 }
768 

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