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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  *      $Id: reassembly.c,v 1.26 2001/03/07 22:00:57 davem Exp $
   9  *
  10  *      Based on: net/ipv4/ip_fragment.c
  11  *
  12  *      This program is free software; you can redistribute it and/or
  13  *      modify it under the terms of the GNU General Public License
  14  *      as published by the Free Software Foundation; either version
  15  *      2 of the License, or (at your option) any later version.
  16  */
  17
  18 /*
  19  *      Fixes:
  20  *      Andi Kleen      Make it work with multiple hosts.
  21  *                      More RFC compliance.
  22  *
  23  *      Horst von Brand Add missing #include <linux/string.h>
  24  *      Alexey Kuznetsov        SMP races, threading, cleanup.
  25  *      Patrick McHardy         LRU queue of frag heads for evictor.
  26  *      Mitsuru KANDA @USAGI    Register inet6_protocol{}.
  27  *      David Stevens and
  28  *      YOSHIFUJI,H. @USAGI     Always remove fragment header to
  29  *                              calculate ICV correctly.
  30  */
  31 #include <linux/errno.h>
  32 #include <linux/types.h>
  33 #include <linux/string.h>
  34 #include <linux/socket.h>
  35 #include <linux/sockios.h>
  36 #include <linux/jiffies.h>
  37 #include <linux/net.h>
  38 #include <linux/list.h>
  39 #include <linux/netdevice.h>
  40 #include <linux/in6.h>
  41 #include <linux/ipv6.h>
  42 #include <linux/icmpv6.h>
  43 #include <linux/random.h>
  44 #include <linux/jhash.h>
  45 #include <linux/skbuff.h>
  46
  47 #include <net/sock.h>
  48 #include <net/snmp.h>
  49
  50 #include <net/ipv6.h>
  51 #include <net/ip6_route.h>
  52 #include <net/protocol.h>
  53 #include <net/transp_v6.h>
  54 #include <net/rawv6.h>
  55 #include <net/ndisc.h>
  56 #include <net/addrconf.h>
  57 #include <net/inet_frag.h>
  58
  59 struct ip6frag_skb_cb
  60 {
  61         struct inet6_skb_parm   h;
  62         int                     offset;
  63 };
  64
  65 #define FRAG6_CB(skb)   ((struct ip6frag_skb_cb*)((skb)->cb))
  66
  67
  68 /*
  69  *      Equivalent of ipv4 struct ipq
  70  */
  71
  72 struct frag_queue
  73 {
  74         struct inet_frag_queue  q;
  75
  76         __be32                  id;             /* fragment id          */
  77         struct in6_addr         saddr;
  78         struct in6_addr         daddr;
  79
  80         int                     iif;
  81         unsigned int            csum;
  82         __u16                   nhoffset;
  83 };
  84
  85 static struct inet_frags ip6_frags;
  86
  87 int ip6_frag_nqueues(struct net *net)
  88 {
  89         return net->ipv6.frags.nqueues;
  90 }
  91
  92 int ip6_frag_mem(struct net *net)
  93 {
  94         return atomic_read(&net->ipv6.frags.mem);
  95 }
  96
  97 static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff *prev,
  98                           struct net_device *dev);
  99
 100 /*
 101  * callers should be careful not to use the hash value outside the ipfrag_lock
 102  * as doing so could race with ipfrag_hash_rnd being recalculated.
 103  */
 104 static unsigned int ip6qhashfn(__be32 id, struct in6_addr *saddr,
 105                                struct in6_addr *daddr)
 106 {
 107         u32 a, b, c;
 108
 109         a = (__force u32)saddr->s6_addr32[0];
 110         b = (__force u32)saddr->s6_addr32[1];
 111         c = (__force u32)saddr->s6_addr32[2];
 112
 113         a += JHASH_GOLDEN_RATIO;
 114         b += JHASH_GOLDEN_RATIO;
 115         c += ip6_frags.rnd;
 116         __jhash_mix(a, b, c);
 117
 118         a += (__force u32)saddr->s6_addr32[3];
 119         b += (__force u32)daddr->s6_addr32[0];
 120         c += (__force u32)daddr->s6_addr32[1];
 121         __jhash_mix(a, b, c);
 122
 123         a += (__force u32)daddr->s6_addr32[2];
 124         b += (__force u32)daddr->s6_addr32[3];
 125         c += (__force u32)id;
 126         __jhash_mix(a, b, c);
 127
 128         return c & (INETFRAGS_HASHSZ - 1);
 129 }
 130
 131 static unsigned int ip6_hashfn(struct inet_frag_queue *q)
 132 {
 133         struct frag_queue *fq;
 134
 135         fq = container_of(q, struct frag_queue, q);
 136         return ip6qhashfn(fq->id, &fq->saddr, &fq->daddr);
 137 }
 138
 139 int ip6_frag_match(struct inet_frag_queue *q, void *a)
 140 {
 141         struct frag_queue *fq;
 142         struct ip6_create_arg *arg = a;
 143
 144         fq = container_of(q, struct frag_queue, q);
 145         return (fq->id == arg->id &&
 146                         ipv6_addr_equal(&fq->saddr, arg->src) &&
 147                         ipv6_addr_equal(&fq->daddr, arg->dst));
 148 }
 149 EXPORT_SYMBOL(ip6_frag_match);
 150
 151 /* Memory Tracking Functions. */
 152 static inline void frag_kfree_skb(struct netns_frags *nf,
 153                 struct sk_buff *skb, int *work)
 154 {
 155         if (work)
 156                 *work -= skb->truesize;
 157         atomic_sub(skb->truesize, &nf->mem);
 158         kfree_skb(skb);
 159 }
 160
 161 void ip6_frag_init(struct inet_frag_queue *q, void *a)
 162 {
 163         struct frag_queue *fq = container_of(q, struct frag_queue, q);
 164         struct ip6_create_arg *arg = a;
 165
 166         fq->id = arg->id;
 167         ipv6_addr_copy(&fq->saddr, arg->src);
 168         ipv6_addr_copy(&fq->daddr, arg->dst);
 169 }
 170 EXPORT_SYMBOL(ip6_frag_init);
 171
 172 /* Destruction primitives. */
 173
 174 static __inline__ void fq_put(struct frag_queue *fq)
 175 {
 176         inet_frag_put(&fq->q, &ip6_frags);
 177 }
 178
 179 /* Kill fq entry. It is not destroyed immediately,
 180  * because caller (and someone more) holds reference count.
 181  */
 182 static __inline__ void fq_kill(struct frag_queue *fq)
 183 {
 184         inet_frag_kill(&fq->q, &ip6_frags);
 185 }
 186
 187 static void ip6_evictor(struct net *net, struct inet6_dev *idev)
 188 {
 189         int evicted;
 190
 191         evicted = inet_frag_evictor(&net->ipv6.frags, &ip6_frags);
 192         if (evicted)
 193                 IP6_ADD_STATS_BH(idev, IPSTATS_MIB_REASMFAILS, evicted);
 194 }
 195
 196 static void ip6_frag_expire(unsigned long data)
 197 {
 198         struct frag_queue *fq;
 199         struct net_device *dev = NULL;
 200
 201         fq = container_of((struct inet_frag_queue *)data, struct frag_queue, q);
 202
 203         spin_lock(&fq->q.lock);
 204
 205         if (fq->q.last_in & INET_FRAG_COMPLETE)
 206                 goto out;
 207
 208         fq_kill(fq);
 209
 210         dev = dev_get_by_index(&init_net, fq->iif);
 211         if (!dev)
 212                 goto out;
 213
 214         rcu_read_lock();
 215         IP6_INC_STATS_BH(__in6_dev_get(dev), IPSTATS_MIB_REASMTIMEOUT);
 216         IP6_INC_STATS_BH(__in6_dev_get(dev), IPSTATS_MIB_REASMFAILS);
 217         rcu_read_unlock();
 218
 219         /* Don't send error if the first segment did not arrive. */
 220         if (!(fq->q.last_in & INET_FRAG_FIRST_IN) || !fq->q.fragments)
 221                 goto out;
 222
 223         /*
 224            But use as source device on which LAST ARRIVED
 225            segment was received. And do not use fq->dev
 226            pointer directly, device might already disappeared.
 227          */
 228         fq->q.fragments->dev = dev;
 229         icmpv6_send(fq->q.fragments, ICMPV6_TIME_EXCEED, ICMPV6_EXC_FRAGTIME, 0, dev);
 230 out:
 231         if (dev)
 232                 dev_put(dev);
 233         spin_unlock(&fq->q.lock);
 234         fq_put(fq);
 235 }
 236
 237 static __inline__ struct frag_queue *
 238 fq_find(struct net *net, __be32 id, struct in6_addr *src, struct in6_addr *dst,
 239         struct inet6_dev *idev)
 240 {
 241         struct inet_frag_queue *q;
 242         struct ip6_create_arg arg;
 243         unsigned int hash;
 244
 245         arg.id = id;
 246         arg.src = src;
 247         arg.dst = dst;
 248         hash = ip6qhashfn(id, src, dst);
 249
 250         q = inet_frag_find(&net->ipv6.frags, &ip6_frags, &arg, hash);
 251         if (q == NULL)
 252                 goto oom;
 253
 254         return container_of(q, struct frag_queue, q);
 255
 256 oom:
 257         IP6_INC_STATS_BH(idev, IPSTATS_MIB_REASMFAILS);
 258         return NULL;
 259 }
 260
 261 static int ip6_frag_queue(struct frag_queue *fq, struct sk_buff *skb,
 262                            struct frag_hdr *fhdr, int nhoff)
 263 {
 264         struct sk_buff *prev, *next;
 265         struct net_device *dev;
 266         int offset, end;
 267
 268         if (fq->q.last_in & INET_FRAG_COMPLETE)
 269                 goto err;
 270
 271         offset = ntohs(fhdr->frag_off) & ~0x7;
 272         end = offset + (ntohs(ipv6_hdr(skb)->payload_len) -
 273                         ((u8 *)(fhdr + 1) - (u8 *)(ipv6_hdr(skb) + 1)));
 274
 275         if ((unsigned int)end > IPV6_MAXPLEN) {
 276                 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
 277                                  IPSTATS_MIB_INHDRERRORS);
 278                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 279                                   ((u8 *)&fhdr->frag_off -
 280                                    skb_network_header(skb)));
 281                 return -1;
 282         }
 283
 284         if (skb->ip_summed == CHECKSUM_COMPLETE) {
 285                 const unsigned char *nh = skb_network_header(skb);
 286                 skb->csum = csum_sub(skb->csum,
 287                                      csum_partial(nh, (u8 *)(fhdr + 1) - nh,
 288                                                   0));
 289         }
 290
 291         /* Is this the final fragment? */
 292         if (!(fhdr->frag_off & htons(IP6_MF))) {
 293                 /* If we already have some bits beyond end
 294                  * or have different end, the segment is corrupted.
 295                  */
 296                 if (end < fq->q.len ||
 297                     ((fq->q.last_in & INET_FRAG_LAST_IN) && end != fq->q.len))
 298                         goto err;
 299                 fq->q.last_in |= INET_FRAG_LAST_IN;
 300                 fq->q.len = end;
 301         } else {
 302                 /* Check if the fragment is rounded to 8 bytes.
 303                  * Required by the RFC.
 304                  */
 305                 if (end & 0x7) {
 306                         /* RFC2460 says always send parameter problem in
 307                          * this case. -DaveM
 308                          */
 309                         IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
 310                                          IPSTATS_MIB_INHDRERRORS);
 311                         icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 312                                           offsetof(struct ipv6hdr, payload_len));
 313                         return -1;
 314                 }
 315                 if (end > fq->q.len) {
 316                         /* Some bits beyond end -> corruption. */
 317                         if (fq->q.last_in & INET_FRAG_LAST_IN)
 318                                 goto err;
 319                         fq->q.len = end;
 320                 }
 321         }
 322
 323         if (end == offset)
 324                 goto err;
 325
 326         /* Point into the IP datagram 'data' part. */
 327         if (!pskb_pull(skb, (u8 *) (fhdr + 1) - skb->data))
 328                 goto err;
 329
 330         if (pskb_trim_rcsum(skb, end - offset))
 331                 goto err;
 332
 333         /* Find out which fragments are in front and at the back of us
 334          * in the chain of fragments so far.  We must know where to put
 335          * this fragment, right?
 336          */
 337         prev = NULL;
 338         for(next = fq->q.fragments; next != NULL; next = next->next) {
 339                 if (FRAG6_CB(next)->offset >= offset)
 340                         break;  /* bingo! */
 341                 prev = next;
 342         }
 343
 344         /* We found where to put this one.  Check for overlap with
 345          * preceding fragment, and, if needed, align things so that
 346          * any overlaps are eliminated.
 347          */
 348         if (prev) {
 349                 int i = (FRAG6_CB(prev)->offset + prev->len) - offset;
 350
 351                 if (i > 0) {
 352                         offset += i;
 353                         if (end <= offset)
 354                                 goto err;
 355                         if (!pskb_pull(skb, i))
 356                                 goto err;
 357                         if (skb->ip_summed != CHECKSUM_UNNECESSARY)
 358                                 skb->ip_summed = CHECKSUM_NONE;
 359                 }
 360         }
 361
 362         /* Look for overlap with succeeding segments.
 363          * If we can merge fragments, do it.
 364          */
 365         while (next && FRAG6_CB(next)->offset < end) {
 366                 int i = end - FRAG6_CB(next)->offset; /* overlap is 'i' bytes */
 367
 368                 if (i < next->len) {
 369                         /* Eat head of the next overlapped fragment
 370                          * and leave the loop. The next ones cannot overlap.
 371                          */
 372                         if (!pskb_pull(next, i))
 373                                 goto err;
 374                         FRAG6_CB(next)->offset += i;    /* next fragment */
 375                         fq->q.meat -= i;
 376                         if (next->ip_summed != CHECKSUM_UNNECESSARY)
 377                                 next->ip_summed = CHECKSUM_NONE;
 378                         break;
 379                 } else {
 380                         struct sk_buff *free_it = next;
 381
 382                         /* Old fragment is completely overridden with
 383                          * new one drop it.
 384                          */
 385                         next = next->next;
 386
 387                         if (prev)
 388                                 prev->next = next;
 389                         else
 390                                 fq->q.fragments = next;
 391
 392                         fq->q.meat -= free_it->len;
 393                         frag_kfree_skb(fq->q.net, free_it, NULL);
 394                 }
 395         }
 396
 397         FRAG6_CB(skb)->offset = offset;
 398
 399         /* Insert this fragment in the chain of fragments. */
 400         skb->next = next;
 401         if (prev)
 402                 prev->next = skb;
 403         else
 404                 fq->q.fragments = skb;
 405
 406         dev = skb->dev;
 407         if (dev) {
 408                 fq->iif = dev->ifindex;
 409                 skb->dev = NULL;
 410         }
 411         fq->q.stamp = skb->tstamp;
 412         fq->q.meat += skb->len;
 413         atomic_add(skb->truesize, &fq->q.net->mem);
 414
 415         /* The first fragment.
 416          * nhoffset is obtained from the first fragment, of course.
 417          */
 418         if (offset == 0) {
 419                 fq->nhoffset = nhoff;
 420                 fq->q.last_in |= INET_FRAG_FIRST_IN;
 421         }
 422
 423         if (fq->q.last_in == (INET_FRAG_FIRST_IN | INET_FRAG_LAST_IN) &&
 424             fq->q.meat == fq->q.len)
 425                 return ip6_frag_reasm(fq, prev, dev);
 426
 427         write_lock(&ip6_frags.lock);
 428         list_move_tail(&fq->q.lru_list, &fq->q.net->lru_list);
 429         write_unlock(&ip6_frags.lock);
 430         return -1;
 431
 432 err:
 433         IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_REASMFAILS);
 434         kfree_skb(skb);
 435         return -1;
 436 }
 437
 438 /*
 439  *      Check if this packet is complete.
 440  *      Returns NULL on failure by any reason, and pointer
 441  *      to current nexthdr field in reassembled frame.
 442  *
 443  *      It is called with locked fq, and caller must check that
 444  *      queue is eligible for reassembly i.e. it is not COMPLETE,
 445  *      the last and the first frames arrived and all the bits are here.
 446  */
 447 static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff *prev,
 448                           struct net_device *dev)
 449 {
 450         struct sk_buff *fp, *head = fq->q.fragments;
 451         int    payload_len;
 452         unsigned int nhoff;
 453
 454         fq_kill(fq);
 455
 456         /* Make the one we just received the head. */
 457         if (prev) {
 458                 head = prev->next;
 459                 fp = skb_clone(head, GFP_ATOMIC);
 460
 461                 if (!fp)
 462                         goto out_oom;
 463
 464                 fp->next = head->next;
 465                 prev->next = fp;
 466
 467                 skb_morph(head, fq->q.fragments);
 468                 head->next = fq->q.fragments->next;
 469
 470                 kfree_skb(fq->q.fragments);
 471                 fq->q.fragments = head;
 472         }
 473
 474         BUG_TRAP(head != NULL);
 475         BUG_TRAP(FRAG6_CB(head)->offset == 0);
 476
 477         /* Unfragmented part is taken from the first segment. */
 478         payload_len = ((head->data - skb_network_header(head)) -
 479                        sizeof(struct ipv6hdr) + fq->q.len -
 480                        sizeof(struct frag_hdr));
 481         if (payload_len > IPV6_MAXPLEN)
 482                 goto out_oversize;
 483
 484         /* Head of list must not be cloned. */
 485         if (skb_cloned(head) && pskb_expand_head(head, 0, 0, GFP_ATOMIC))
 486                 goto out_oom;
 487
 488         /* If the first fragment is fragmented itself, we split
 489          * it to two chunks: the first with data and paged part
 490          * and the second, holding only fragments. */
 491         if (skb_shinfo(head)->frag_list) {
 492                 struct sk_buff *clone;
 493                 int i, plen = 0;
 494
 495                 if ((clone = alloc_skb(0, GFP_ATOMIC)) == NULL)
 496                         goto out_oom;
 497                 clone->next = head->next;
 498                 head->next = clone;
 499                 skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list;
 500                 skb_shinfo(head)->frag_list = NULL;
 501                 for (i=0; i<skb_shinfo(head)->nr_frags; i++)
 502                         plen += skb_shinfo(head)->frags[i].size;
 503                 clone->len = clone->data_len = head->data_len - plen;
 504                 head->data_len -= clone->len;
 505                 head->len -= clone->len;
 506                 clone->csum = 0;
 507                 clone->ip_summed = head->ip_summed;
 508                 atomic_add(clone->truesize, &fq->q.net->mem);
 509         }
 510
 511         /* We have to remove fragment header from datagram and to relocate
 512          * header in order to calculate ICV correctly. */
 513         nhoff = fq->nhoffset;
 514         skb_network_header(head)[nhoff] = skb_transport_header(head)[0];
 515         memmove(head->head + sizeof(struct frag_hdr), head->head,
 516                 (head->data - head->head) - sizeof(struct frag_hdr));
 517         head->mac_header += sizeof(struct frag_hdr);
 518         head->network_header += sizeof(struct frag_hdr);
 519
 520         skb_shinfo(head)->frag_list = head->next;
 521         skb_reset_transport_header(head);
 522         skb_push(head, head->data - skb_network_header(head));
 523         atomic_sub(head->truesize, &fq->q.net->mem);
 524
 525         for (fp=head->next; fp; fp = fp->next) {
 526                 head->data_len += fp->len;
 527                 head->len += fp->len;
 528                 if (head->ip_summed != fp->ip_summed)
 529                         head->ip_summed = CHECKSUM_NONE;
 530                 else if (head->ip_summed == CHECKSUM_COMPLETE)
 531                         head->csum = csum_add(head->csum, fp->csum);
 532                 head->truesize += fp->truesize;
 533                 atomic_sub(fp->truesize, &fq->q.net->mem);
 534         }
 535
 536         head->next = NULL;
 537         head->dev = dev;
 538         head->tstamp = fq->q.stamp;
 539         ipv6_hdr(head)->payload_len = htons(payload_len);
 540         IP6CB(head)->nhoff = nhoff;
 541
 542         /* Yes, and fold redundant checksum back. 8) */
 543         if (head->ip_summed == CHECKSUM_COMPLETE)
 544                 head->csum = csum_partial(skb_network_header(head),
 545                                           skb_network_header_len(head),
 546                                           head->csum);
 547
 548         rcu_read_lock();
 549         IP6_INC_STATS_BH(__in6_dev_get(dev), IPSTATS_MIB_REASMOKS);
 550         rcu_read_unlock();
 551         fq->q.fragments = NULL;
 552         return 1;
 553
 554 out_oversize:
 555         if (net_ratelimit())
 556                 printk(KERN_DEBUG "ip6_frag_reasm: payload len = %d\n", payload_len);
 557         goto out_fail;
 558 out_oom:
 559         if (net_ratelimit())
 560                 printk(KERN_DEBUG "ip6_frag_reasm: no memory for reassembly\n");
 561 out_fail:
 562         rcu_read_lock();
 563         IP6_INC_STATS_BH(__in6_dev_get(dev), IPSTATS_MIB_REASMFAILS);
 564         rcu_read_unlock();
 565         return -1;
 566 }
 567
 568 static int ipv6_frag_rcv(struct sk_buff *skb)
 569 {
 570         struct frag_hdr *fhdr;
 571         struct frag_queue *fq;
 572         struct ipv6hdr *hdr = ipv6_hdr(skb);
 573         struct net *net;
 574
 575         IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_REASMREQDS);
 576
 577         /* Jumbo payload inhibits frag. header */
 578         if (hdr->payload_len==0) {
 579                 IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_INHDRERRORS);
 580                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 581                                   skb_network_header_len(skb));
 582                 return -1;
 583         }
 584         if (!pskb_may_pull(skb, (skb_transport_offset(skb) +
 585                                  sizeof(struct frag_hdr)))) {
 586                 IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_INHDRERRORS);
 587                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 588                                   skb_network_header_len(skb));
 589                 return -1;
 590         }
 591
 592         hdr = ipv6_hdr(skb);
 593         fhdr = (struct frag_hdr *)skb_transport_header(skb);
 594
 595         if (!(fhdr->frag_off & htons(0xFFF9))) {
 596                 /* It is not a fragmented frame */
 597                 skb->transport_header += sizeof(struct frag_hdr);
 598                 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_REASMOKS);
 599
 600                 IP6CB(skb)->nhoff = (u8 *)fhdr - skb_network_header(skb);
 601                 return 1;
 602         }
 603
 604         net = dev_net(skb->dev);
 605         if (atomic_read(&net->ipv6.frags.mem) > net->ipv6.frags.high_thresh)
 606                 ip6_evictor(net, ip6_dst_idev(skb->dst));
 607
 608         if ((fq = fq_find(net, fhdr->identification, &hdr->saddr, &hdr->daddr,
 609                           ip6_dst_idev(skb->dst))) != NULL) {
 610                 int ret;
 611
 612                 spin_lock(&fq->q.lock);
 613
 614                 ret = ip6_frag_queue(fq, skb, fhdr, IP6CB(skb)->nhoff);
 615
 616                 spin_unlock(&fq->q.lock);
 617                 fq_put(fq);
 618                 return ret;
 619         }
 620
 621         IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_REASMFAILS);
 622         kfree_skb(skb);
 623         return -1;
 624 }
 625
 626 static struct inet6_protocol frag_protocol =
 627 {
 628         .handler        =       ipv6_frag_rcv,
 629         .flags          =       INET6_PROTO_NOPOLICY,
 630 };
 631
 632 #ifdef CONFIG_SYSCTL
 633 static struct ctl_table ip6_frags_ctl_table[] = {
 634         {
 635                 .ctl_name       = NET_IPV6_IP6FRAG_HIGH_THRESH,
 636                 .procname       = "ip6frag_high_thresh",
 637                 .data           = &init_net.ipv6.frags.high_thresh,
 638                 .maxlen         = sizeof(int),
 639                 .mode           = 0644,
 640                 .proc_handler   = &proc_dointvec
 641         },
 642         {
 643                 .ctl_name       = NET_IPV6_IP6FRAG_LOW_THRESH,
 644                 .procname       = "ip6frag_low_thresh",
 645                 .data           = &init_net.ipv6.frags.low_thresh,
 646                 .maxlen         = sizeof(int),
 647                 .mode           = 0644,
 648                 .proc_handler   = &proc_dointvec
 649         },
 650         {
 651                 .ctl_name       = NET_IPV6_IP6FRAG_TIME,
 652                 .procname       = "ip6frag_time",
 653                 .data           = &init_net.ipv6.frags.timeout,
 654                 .maxlen         = sizeof(int),
 655                 .mode           = 0644,
 656                 .proc_handler   = &proc_dointvec_jiffies,
 657                 .strategy       = &sysctl_jiffies,
 658         },
 659         {
 660                 .ctl_name       = NET_IPV6_IP6FRAG_SECRET_INTERVAL,
 661                 .procname       = "ip6frag_secret_interval",
 662                 .data           = &ip6_frags.secret_interval,
 663                 .maxlen         = sizeof(int),
 664                 .mode           = 0644,
 665                 .proc_handler   = &proc_dointvec_jiffies,
 666                 .strategy       = &sysctl_jiffies
 667         },
 668         { }
 669 };
 670
 671 static int ip6_frags_sysctl_register(struct net *net)
 672 {
 673         struct ctl_table *table;
 674         struct ctl_table_header *hdr;
 675
 676         table = ip6_frags_ctl_table;
 677         if (net != &init_net) {
 678                 table = kmemdup(table, sizeof(ip6_frags_ctl_table), GFP_KERNEL);
 679                 if (table == NULL)
 680                         goto err_alloc;
 681
 682                 table[0].data = &net->ipv6.frags.high_thresh;
 683                 table[1].data = &net->ipv6.frags.low_thresh;
 684                 table[2].data = &net->ipv6.frags.timeout;
 685                 table[3].mode &= ~0222;
 686         }
 687
 688         hdr = register_net_sysctl_table(net, net_ipv6_ctl_path, table);
 689         if (hdr == NULL)
 690                 goto err_reg;
 691
 692         net->ipv6.sysctl.frags_hdr = hdr;
 693         return 0;
 694
 695 err_reg:
 696         if (net != &init_net)
 697                 kfree(table);
 698 err_alloc:
 699         return -ENOMEM;
 700 }
 701
 702 static void ip6_frags_sysctl_unregister(struct net *net)
 703 {
 704         struct ctl_table *table;
 705
 706         table = net->ipv6.sysctl.frags_hdr->ctl_table_arg;
 707         unregister_net_sysctl_table(net->ipv6.sysctl.frags_hdr);
 708         kfree(table);
 709 }
 710 #else
 711 static inline int ip6_frags_sysctl_register(struct net *net)
 712 {
 713         return 0;
 714 }
 715
 716 static inline void ip6_frags_sysctl_unregister(struct net *net)
 717 {
 718 }
 719 #endif
 720
 721 static int ipv6_frags_init_net(struct net *net)
 722 {
 723         net->ipv6.frags.high_thresh = 256 * 1024;
 724         net->ipv6.frags.low_thresh = 192 * 1024;
 725         net->ipv6.frags.timeout = IPV6_FRAG_TIMEOUT;
 726
 727         inet_frags_init_net(&net->ipv6.frags);
 728
 729         return ip6_frags_sysctl_register(net);
 730 }
 731
 732 static void ipv6_frags_exit_net(struct net *net)
 733 {
 734         ip6_frags_sysctl_unregister(net);
 735         inet_frags_exit_net(&net->ipv6.frags, &ip6_frags);
 736 }
 737
 738 static struct pernet_operations ip6_frags_ops = {
 739         .init = ipv6_frags_init_net,
 740         .exit = ipv6_frags_exit_net,
 741 };
 742
 743 int __init ipv6_frag_init(void)
 744 {
 745         int ret;
 746
 747         ret = inet6_add_protocol(&frag_protocol, IPPROTO_FRAGMENT);
 748         if (ret)
 749                 goto out;
 750
 751         register_pernet_subsys(&ip6_frags_ops);
 752
 753         ip6_frags.hashfn = ip6_hashfn;
 754         ip6_frags.constructor = ip6_frag_init;
 755         ip6_frags.destructor = NULL;
 756         ip6_frags.skb_free = 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.secret_interval = 10 * 60 * HZ;
 761         inet_frags_init(&ip6_frags);
 762 out:
 763         return ret;
 764 }
 765
 766 void ipv6_frag_exit(void)
 767 {
 768         inet_frags_fini(&ip6_frags);
 769         unregister_pernet_subsys(&ip6_frags_ops);
 770         inet6_del_protocol(&frag_protocol, IPPROTO_FRAGMENT);
 771 }