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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_BH(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_BH(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(unsigned long data)
174 {
175         struct frag_queue *fq;
176         struct net *net;
177 
178         fq = container_of((struct inet_frag_queue *)data, struct frag_queue, q);
179         net = container_of(fq->q.net, struct net, ipv6.frags);
180 
181         ip6_expire_frag_queue(net, fq, &ip6_frags);
182 }
183 
184 static struct frag_queue *
185 fq_find(struct net *net, __be32 id, const struct in6_addr *src,
186         const struct in6_addr *dst, int iif, u8 ecn)
187 {
188         struct inet_frag_queue *q;
189         struct ip6_create_arg arg;
190         unsigned int hash;
191 
192         arg.id = id;
193         arg.user = IP6_DEFRAG_LOCAL_DELIVER;
194         arg.src = src;
195         arg.dst = dst;
196         arg.iif = iif;
197         arg.ecn = ecn;
198 
199         hash = inet6_hash_frag(id, src, dst);
200 
201         q = inet_frag_find(&net->ipv6.frags, &ip6_frags, &arg, hash);
202         if (IS_ERR_OR_NULL(q)) {
203                 inet_frag_maybe_warn_overflow(q, pr_fmt());
204                 return NULL;
205         }
206         return container_of(q, struct frag_queue, q);
207 }
208 
209 static int ip6_frag_queue(struct frag_queue *fq, struct sk_buff *skb,
210                            struct frag_hdr *fhdr, int nhoff)
211 {
212         struct sk_buff *prev, *next;
213         struct net_device *dev;
214         int offset, end;
215         struct net *net = dev_net(skb_dst(skb)->dev);
216         u8 ecn;
217 
218         if (fq->q.flags & INET_FRAG_COMPLETE)
219                 goto err;
220 
221         offset = ntohs(fhdr->frag_off) & ~0x7;
222         end = offset + (ntohs(ipv6_hdr(skb)->payload_len) -
223                         ((u8 *)(fhdr + 1) - (u8 *)(ipv6_hdr(skb) + 1)));
224 
225         if ((unsigned int)end > IPV6_MAXPLEN) {
226                 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
227                                  IPSTATS_MIB_INHDRERRORS);
228                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
229                                   ((u8 *)&fhdr->frag_off -
230                                    skb_network_header(skb)));
231                 return -1;
232         }
233 
234         ecn = ip6_frag_ecn(ipv6_hdr(skb));
235 
236         if (skb->ip_summed == CHECKSUM_COMPLETE) {
237                 const unsigned char *nh = skb_network_header(skb);
238                 skb->csum = csum_sub(skb->csum,
239                                      csum_partial(nh, (u8 *)(fhdr + 1) - nh,
240                                                   0));
241         }
242 
243         /* Is this the final fragment? */
244         if (!(fhdr->frag_off & htons(IP6_MF))) {
245                 /* If we already have some bits beyond end
246                  * or have different end, the segment is corrupted.
247                  */
248                 if (end < fq->q.len ||
249                     ((fq->q.flags & INET_FRAG_LAST_IN) && end != fq->q.len))
250                         goto err;
251                 fq->q.flags |= INET_FRAG_LAST_IN;
252                 fq->q.len = end;
253         } else {
254                 /* Check if the fragment is rounded to 8 bytes.
255                  * Required by the RFC.
256                  */
257                 if (end & 0x7) {
258                         /* RFC2460 says always send parameter problem in
259                          * this case. -DaveM
260                          */
261                         IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
262                                          IPSTATS_MIB_INHDRERRORS);
263                         icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
264                                           offsetof(struct ipv6hdr, payload_len));
265                         return -1;
266                 }
267                 if (end > fq->q.len) {
268                         /* Some bits beyond end -> corruption. */
269                         if (fq->q.flags & INET_FRAG_LAST_IN)
270                                 goto err;
271                         fq->q.len = end;
272                 }
273         }
274 
275         if (end == offset)
276                 goto err;
277 
278         /* Point into the IP datagram 'data' part. */
279         if (!pskb_pull(skb, (u8 *) (fhdr + 1) - skb->data))
280                 goto err;
281 
282         if (pskb_trim_rcsum(skb, end - offset))
283                 goto err;
284 
285         /* Find out which fragments are in front and at the back of us
286          * in the chain of fragments so far.  We must know where to put
287          * this fragment, right?
288          */
289         prev = fq->q.fragments_tail;
290         if (!prev || FRAG6_CB(prev)->offset < offset) {
291                 next = NULL;
292                 goto found;
293         }
294         prev = NULL;
295         for (next = fq->q.fragments; next != NULL; next = next->next) {
296                 if (FRAG6_CB(next)->offset >= offset)
297                         break;  /* bingo! */
298                 prev = next;
299         }
300 
301 found:
302         /* RFC5722, Section 4, amended by Errata ID : 3089
303          *                          When reassembling an IPv6 datagram, if
304          *   one or more its constituent fragments is determined to be an
305          *   overlapping fragment, the entire datagram (and any constituent
306          *   fragments) MUST be silently discarded.
307          */
308 
309         /* Check for overlap with preceding fragment. */
310         if (prev &&
311             (FRAG6_CB(prev)->offset + prev->len) > offset)
312                 goto discard_fq;
313 
314         /* Look for overlap with succeeding segment. */
315         if (next && FRAG6_CB(next)->offset < end)
316                 goto discard_fq;
317 
318         FRAG6_CB(skb)->offset = offset;
319 
320         /* Insert this fragment in the chain of fragments. */
321         skb->next = next;
322         if (!next)
323                 fq->q.fragments_tail = skb;
324         if (prev)
325                 prev->next = skb;
326         else
327                 fq->q.fragments = skb;
328 
329         dev = skb->dev;
330         if (dev) {
331                 fq->iif = dev->ifindex;
332                 skb->dev = NULL;
333         }
334         fq->q.stamp = skb->tstamp;
335         fq->q.meat += skb->len;
336         fq->ecn |= ecn;
337         add_frag_mem_limit(fq->q.net, skb->truesize);
338 
339         /* The first fragment.
340          * nhoffset is obtained from the first fragment, of course.
341          */
342         if (offset == 0) {
343                 fq->nhoffset = nhoff;
344                 fq->q.flags |= INET_FRAG_FIRST_IN;
345         }
346 
347         if (fq->q.flags == (INET_FRAG_FIRST_IN | INET_FRAG_LAST_IN) &&
348             fq->q.meat == fq->q.len) {
349                 int res;
350                 unsigned long orefdst = skb->_skb_refdst;
351 
352                 skb->_skb_refdst = 0UL;
353                 res = ip6_frag_reasm(fq, prev, dev);
354                 skb->_skb_refdst = orefdst;
355                 return res;
356         }
357 
358         skb_dst_drop(skb);
359         return -1;
360 
361 discard_fq:
362         inet_frag_kill(&fq->q, &ip6_frags);
363 err:
364         IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
365                          IPSTATS_MIB_REASMFAILS);
366         kfree_skb(skb);
367         return -1;
368 }
369 
370 /*
371  *      Check if this packet is complete.
372  *      Returns NULL on failure by any reason, and pointer
373  *      to current nexthdr field in reassembled frame.
374  *
375  *      It is called with locked fq, and caller must check that
376  *      queue is eligible for reassembly i.e. it is not COMPLETE,
377  *      the last and the first frames arrived and all the bits are here.
378  */
379 static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff *prev,
380                           struct net_device *dev)
381 {
382         struct net *net = container_of(fq->q.net, struct net, ipv6.frags);
383         struct sk_buff *fp, *head = fq->q.fragments;
384         int    payload_len;
385         unsigned int nhoff;
386         int sum_truesize;
387         u8 ecn;
388 
389         inet_frag_kill(&fq->q, &ip6_frags);
390 
391         ecn = ip_frag_ecn_table[fq->ecn];
392         if (unlikely(ecn == 0xff))
393                 goto out_fail;
394 
395         /* Make the one we just received the head. */
396         if (prev) {
397                 head = prev->next;
398                 fp = skb_clone(head, GFP_ATOMIC);
399 
400                 if (!fp)
401                         goto out_oom;
402 
403                 fp->next = head->next;
404                 if (!fp->next)
405                         fq->q.fragments_tail = fp;
406                 prev->next = fp;
407 
408                 skb_morph(head, fq->q.fragments);
409                 head->next = fq->q.fragments->next;
410 
411                 consume_skb(fq->q.fragments);
412                 fq->q.fragments = head;
413         }
414 
415         WARN_ON(head == NULL);
416         WARN_ON(FRAG6_CB(head)->offset != 0);
417 
418         /* Unfragmented part is taken from the first segment. */
419         payload_len = ((head->data - skb_network_header(head)) -
420                        sizeof(struct ipv6hdr) + fq->q.len -
421                        sizeof(struct frag_hdr));
422         if (payload_len > IPV6_MAXPLEN)
423                 goto out_oversize;
424 
425         /* Head of list must not be cloned. */
426         if (skb_unclone(head, GFP_ATOMIC))
427                 goto out_oom;
428 
429         /* If the first fragment is fragmented itself, we split
430          * it to two chunks: the first with data and paged part
431          * and the second, holding only fragments. */
432         if (skb_has_frag_list(head)) {
433                 struct sk_buff *clone;
434                 int i, plen = 0;
435 
436                 clone = alloc_skb(0, GFP_ATOMIC);
437                 if (!clone)
438                         goto out_oom;
439                 clone->next = head->next;
440                 head->next = clone;
441                 skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list;
442                 skb_frag_list_init(head);
443                 for (i = 0; i < skb_shinfo(head)->nr_frags; i++)
444                         plen += skb_frag_size(&skb_shinfo(head)->frags[i]);
445                 clone->len = clone->data_len = head->data_len - plen;
446                 head->data_len -= clone->len;
447                 head->len -= clone->len;
448                 clone->csum = 0;
449                 clone->ip_summed = head->ip_summed;
450                 add_frag_mem_limit(fq->q.net, clone->truesize);
451         }
452 
453         /* We have to remove fragment header from datagram and to relocate
454          * header in order to calculate ICV correctly. */
455         nhoff = fq->nhoffset;
456         skb_network_header(head)[nhoff] = skb_transport_header(head)[0];
457         memmove(head->head + sizeof(struct frag_hdr), head->head,
458                 (head->data - head->head) - sizeof(struct frag_hdr));
459         head->mac_header += sizeof(struct frag_hdr);
460         head->network_header += sizeof(struct frag_hdr);
461 
462         skb_reset_transport_header(head);
463         skb_push(head, head->data - skb_network_header(head));
464 
465         sum_truesize = head->truesize;
466         for (fp = head->next; fp;) {
467                 bool headstolen;
468                 int delta;
469                 struct sk_buff *next = fp->next;
470 
471                 sum_truesize += fp->truesize;
472                 if (head->ip_summed != fp->ip_summed)
473                         head->ip_summed = CHECKSUM_NONE;
474                 else if (head->ip_summed == CHECKSUM_COMPLETE)
475                         head->csum = csum_add(head->csum, fp->csum);
476 
477                 if (skb_try_coalesce(head, fp, &headstolen, &delta)) {
478                         kfree_skb_partial(fp, headstolen);
479                 } else {
480                         if (!skb_shinfo(head)->frag_list)
481                                 skb_shinfo(head)->frag_list = fp;
482                         head->data_len += fp->len;
483                         head->len += fp->len;
484                         head->truesize += fp->truesize;
485                 }
486                 fp = next;
487         }
488         sub_frag_mem_limit(fq->q.net, sum_truesize);
489 
490         head->next = NULL;
491         head->dev = dev;
492         head->tstamp = fq->q.stamp;
493         ipv6_hdr(head)->payload_len = htons(payload_len);
494         ipv6_change_dsfield(ipv6_hdr(head), 0xff, ecn);
495         IP6CB(head)->nhoff = nhoff;
496         IP6CB(head)->flags |= IP6SKB_FRAGMENTED;
497 
498         /* Yes, and fold redundant checksum back. 8) */
499         skb_postpush_rcsum(head, skb_network_header(head),
500                            skb_network_header_len(head));
501 
502         rcu_read_lock();
503         IP6_INC_STATS_BH(net, __in6_dev_get(dev), IPSTATS_MIB_REASMOKS);
504         rcu_read_unlock();
505         fq->q.fragments = NULL;
506         fq->q.fragments_tail = NULL;
507         return 1;
508 
509 out_oversize:
510         net_dbg_ratelimited("ip6_frag_reasm: payload len = %d\n", payload_len);
511         goto out_fail;
512 out_oom:
513         net_dbg_ratelimited("ip6_frag_reasm: no memory for reassembly\n");
514 out_fail:
515         rcu_read_lock();
516         IP6_INC_STATS_BH(net, __in6_dev_get(dev), IPSTATS_MIB_REASMFAILS);
517         rcu_read_unlock();
518         return -1;
519 }
520 
521 static int ipv6_frag_rcv(struct sk_buff *skb)
522 {
523         struct frag_hdr *fhdr;
524         struct frag_queue *fq;
525         const struct ipv6hdr *hdr = ipv6_hdr(skb);
526         struct net *net = dev_net(skb_dst(skb)->dev);
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         fq = fq_find(net, fhdr->identification, &hdr->saddr, &hdr->daddr,
556                      skb->dev ? skb->dev->ifindex : 0, ip6_frag_ecn(hdr));
557         if (fq) {
558                 int ret;
559 
560                 spin_lock(&fq->q.lock);
561 
562                 ret = ip6_frag_queue(fq, skb, fhdr, IP6CB(skb)->nhoff);
563 
564                 spin_unlock(&fq->q.lock);
565                 inet_frag_put(&fq->q, &ip6_frags);
566                 return ret;
567         }
568 
569         IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_REASMFAILS);
570         kfree_skb(skb);
571         return -1;
572 
573 fail_hdr:
574         IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
575                          IPSTATS_MIB_INHDRERRORS);
576         icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, skb_network_header_len(skb));
577         return -1;
578 }
579 
580 static const struct inet6_protocol frag_protocol = {
581         .handler        =       ipv6_frag_rcv,
582         .flags          =       INET6_PROTO_NOPOLICY,
583 };
584 
585 #ifdef CONFIG_SYSCTL
586 static int zero;
587 
588 static struct ctl_table ip6_frags_ns_ctl_table[] = {
589         {
590                 .procname       = "ip6frag_high_thresh",
591                 .data           = &init_net.ipv6.frags.high_thresh,
592                 .maxlen         = sizeof(int),
593                 .mode           = 0644,
594                 .proc_handler   = proc_dointvec_minmax,
595                 .extra1         = &init_net.ipv6.frags.low_thresh
596         },
597         {
598                 .procname       = "ip6frag_low_thresh",
599                 .data           = &init_net.ipv6.frags.low_thresh,
600                 .maxlen         = sizeof(int),
601                 .mode           = 0644,
602                 .proc_handler   = proc_dointvec_minmax,
603                 .extra1         = &zero,
604                 .extra2         = &init_net.ipv6.frags.high_thresh
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 /* secret interval has been deprecated */
617 static int ip6_frags_secret_interval_unused;
618 static struct ctl_table ip6_frags_ctl_table[] = {
619         {
620                 .procname       = "ip6frag_secret_interval",
621                 .data           = &ip6_frags_secret_interval_unused,
622                 .maxlen         = sizeof(int),
623                 .mode           = 0644,
624                 .proc_handler   = proc_dointvec_jiffies,
625         },
626         { }
627 };
628 
629 static int __net_init ip6_frags_ns_sysctl_register(struct net *net)
630 {
631         struct ctl_table *table;
632         struct ctl_table_header *hdr;
633 
634         table = ip6_frags_ns_ctl_table;
635         if (!net_eq(net, &init_net)) {
636                 table = kmemdup(table, sizeof(ip6_frags_ns_ctl_table), GFP_KERNEL);
637                 if (!table)
638                         goto err_alloc;
639 
640                 table[0].data = &net->ipv6.frags.high_thresh;
641                 table[0].extra1 = &net->ipv6.frags.low_thresh;
642                 table[0].extra2 = &init_net.ipv6.frags.high_thresh;
643                 table[1].data = &net->ipv6.frags.low_thresh;
644                 table[1].extra2 = &net->ipv6.frags.high_thresh;
645                 table[2].data = &net->ipv6.frags.timeout;
646 
647                 /* Don't export sysctls to unprivileged users */
648                 if (net->user_ns != &init_user_ns)
649                         table[0].procname = NULL;
650         }
651 
652         hdr = register_net_sysctl(net, "net/ipv6", table);
653         if (!hdr)
654                 goto err_reg;
655 
656         net->ipv6.sysctl.frags_hdr = hdr;
657         return 0;
658 
659 err_reg:
660         if (!net_eq(net, &init_net))
661                 kfree(table);
662 err_alloc:
663         return -ENOMEM;
664 }
665 
666 static void __net_exit ip6_frags_ns_sysctl_unregister(struct net *net)
667 {
668         struct ctl_table *table;
669 
670         table = net->ipv6.sysctl.frags_hdr->ctl_table_arg;
671         unregister_net_sysctl_table(net->ipv6.sysctl.frags_hdr);
672         if (!net_eq(net, &init_net))
673                 kfree(table);
674 }
675 
676 static struct ctl_table_header *ip6_ctl_header;
677 
678 static int ip6_frags_sysctl_register(void)
679 {
680         ip6_ctl_header = register_net_sysctl(&init_net, "net/ipv6",
681                         ip6_frags_ctl_table);
682         return ip6_ctl_header == NULL ? -ENOMEM : 0;
683 }
684 
685 static void ip6_frags_sysctl_unregister(void)
686 {
687         unregister_net_sysctl_table(ip6_ctl_header);
688 }
689 #else
690 static int ip6_frags_ns_sysctl_register(struct net *net)
691 {
692         return 0;
693 }
694 
695 static void ip6_frags_ns_sysctl_unregister(struct net *net)
696 {
697 }
698 
699 static int ip6_frags_sysctl_register(void)
700 {
701         return 0;
702 }
703 
704 static void ip6_frags_sysctl_unregister(void)
705 {
706 }
707 #endif
708 
709 static int __net_init ipv6_frags_init_net(struct net *net)
710 {
711         int res;
712 
713         net->ipv6.frags.high_thresh = IPV6_FRAG_HIGH_THRESH;
714         net->ipv6.frags.low_thresh = IPV6_FRAG_LOW_THRESH;
715         net->ipv6.frags.timeout = IPV6_FRAG_TIMEOUT;
716 
717         res = inet_frags_init_net(&net->ipv6.frags);
718         if (res)
719                 return res;
720         res = ip6_frags_ns_sysctl_register(net);
721         if (res)
722                 inet_frags_uninit_net(&net->ipv6.frags);
723         return res;
724 }
725 
726 static void __net_exit ipv6_frags_exit_net(struct net *net)
727 {
728         ip6_frags_ns_sysctl_unregister(net);
729         inet_frags_exit_net(&net->ipv6.frags, &ip6_frags);
730 }
731 
732 static struct pernet_operations ip6_frags_ops = {
733         .init = ipv6_frags_init_net,
734         .exit = ipv6_frags_exit_net,
735 };
736 
737 int __init ipv6_frag_init(void)
738 {
739         int ret;
740 
741         ret = inet6_add_protocol(&frag_protocol, IPPROTO_FRAGMENT);
742         if (ret)
743                 goto out;
744 
745         ret = ip6_frags_sysctl_register();
746         if (ret)
747                 goto err_sysctl;
748 
749         ret = register_pernet_subsys(&ip6_frags_ops);
750         if (ret)
751                 goto err_pernet;
752 
753         ip6_frags.hashfn = ip6_hashfn;
754         ip6_frags.constructor = ip6_frag_init;
755         ip6_frags.destructor = NULL;
756         ip6_frags.qsize = sizeof(struct frag_queue);
757         ip6_frags.match = ip6_frag_match;
758         ip6_frags.frag_expire = ip6_frag_expire;
759         ip6_frags.frags_cache_name = ip6_frag_cache_name;
760         ret = inet_frags_init(&ip6_frags);
761         if (ret)
762                 goto err_pernet;
763 out:
764         return ret;
765 
766 err_pernet:
767         ip6_frags_sysctl_unregister();
768 err_sysctl:
769         inet6_del_protocol(&frag_protocol, IPPROTO_FRAGMENT);
770         goto out;
771 }
772 
773 void ipv6_frag_exit(void)
774 {
775         inet_frags_fini(&ip6_frags);
776         ip6_frags_sysctl_unregister();
777         unregister_pernet_subsys(&ip6_frags_ops);
778         inet6_del_protocol(&frag_protocol, IPPROTO_FRAGMENT);
779 }
780 

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