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#include <linux/errno.h>
  30#include <linux/types.h>
  31#include <linux/string.h>
  32#include <linux/socket.h>
  33#include <linux/sockios.h>
  34#include <linux/jiffies.h>
  35#include <linux/net.h>
  36#include <linux/list.h>
  37#include <linux/netdevice.h>
  38#include <linux/in6.h>
  39#include <linux/ipv6.h>
  40#include <linux/icmpv6.h>
  41#include <linux/random.h>
  42#include <linux/jhash.h>
  43#include <linux/skbuff.h>
  44#include <linux/slab.h>
  45#include <linux/export.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
  59struct 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
  72struct frag_queue
  73{
  74        struct inet_frag_queue  q;
  75
  76        __be32                  id;             /* fragment id          */
  77        u32                     user;
  78        struct in6_addr         saddr;
  79        struct in6_addr         daddr;
  80
  81        int                     iif;
  82        unsigned int            csum;
  83        __u16                   nhoffset;
  84};
  85
  86static struct inet_frags ip6_frags;
  87
  88int ip6_frag_nqueues(struct net *net)
  89{
  90        return net->ipv6.frags.nqueues;
  91}
  92
  93int ip6_frag_mem(struct net *net)
  94{
  95        return atomic_read(&net->ipv6.frags.mem);
  96}
  97
  98static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff *prev,
  99                          struct net_device *dev);
 100
 101/*
 102 * callers should be careful not to use the hash value outside the ipfrag_lock
 103 * as doing so could race with ipfrag_hash_rnd being recalculated.
 104 */
 105unsigned int inet6_hash_frag(__be32 id, const struct in6_addr *saddr,
 106                             const struct in6_addr *daddr, u32 rnd)
 107{
 108        u32 c;
 109
 110        c = jhash_3words((__force u32)saddr->s6_addr32[0],
 111                         (__force u32)saddr->s6_addr32[1],
 112                         (__force u32)saddr->s6_addr32[2],
 113                         rnd);
 114
 115        c = jhash_3words((__force u32)saddr->s6_addr32[3],
 116                         (__force u32)daddr->s6_addr32[0],
 117                         (__force u32)daddr->s6_addr32[1],
 118                         c);
 119
 120        c =  jhash_3words((__force u32)daddr->s6_addr32[2],
 121                          (__force u32)daddr->s6_addr32[3],
 122                          (__force u32)id,
 123                          c);
 124
 125        return c & (INETFRAGS_HASHSZ - 1);
 126}
 127EXPORT_SYMBOL_GPL(inet6_hash_frag);
 128
 129static unsigned int ip6_hashfn(struct inet_frag_queue *q)
 130{
 131        struct frag_queue *fq;
 132
 133        fq = container_of(q, struct frag_queue, q);
 134        return inet6_hash_frag(fq->id, &fq->saddr, &fq->daddr, ip6_frags.rnd);
 135}
 136
 137bool ip6_frag_match(struct inet_frag_queue *q, void *a)
 138{
 139        struct frag_queue *fq;
 140        struct ip6_create_arg *arg = a;
 141
 142        fq = container_of(q, struct frag_queue, q);
 143        return  fq->id == arg->id &&
 144                fq->user == arg->user &&
 145                ipv6_addr_equal(&fq->saddr, arg->src) &&
 146                ipv6_addr_equal(&fq->daddr, arg->dst);
 147}
 148EXPORT_SYMBOL(ip6_frag_match);
 149
 150void ip6_frag_init(struct inet_frag_queue *q, void *a)
 151{
 152        struct frag_queue *fq = container_of(q, struct frag_queue, q);
 153        struct ip6_create_arg *arg = a;
 154
 155        fq->id = arg->id;
 156        fq->user = arg->user;
 157        fq->saddr = *arg->src;
 158        fq->daddr = *arg->dst;
 159}
 160EXPORT_SYMBOL(ip6_frag_init);
 161
 162/* Destruction primitives. */
 163
 164static __inline__ void fq_put(struct frag_queue *fq)
 165{
 166        inet_frag_put(&fq->q, &ip6_frags);
 167}
 168
 169/* Kill fq entry. It is not destroyed immediately,
 170 * because caller (and someone more) holds reference count.
 171 */
 172static __inline__ void fq_kill(struct frag_queue *fq)
 173{
 174        inet_frag_kill(&fq->q, &ip6_frags);
 175}
 176
 177static void ip6_evictor(struct net *net, struct inet6_dev *idev)
 178{
 179        int evicted;
 180
 181        evicted = inet_frag_evictor(&net->ipv6.frags, &ip6_frags);
 182        if (evicted)
 183                IP6_ADD_STATS_BH(net, idev, IPSTATS_MIB_REASMFAILS, evicted);
 184}
 185
 186static void ip6_frag_expire(unsigned long data)
 187{
 188        struct frag_queue *fq;
 189        struct net_device *dev = NULL;
 190        struct net *net;
 191
 192        fq = container_of((struct inet_frag_queue *)data, struct frag_queue, q);
 193
 194        spin_lock(&fq->q.lock);
 195
 196        if (fq->q.last_in & INET_FRAG_COMPLETE)
 197                goto out;
 198
 199        fq_kill(fq);
 200
 201        net = container_of(fq->q.net, struct net, ipv6.frags);
 202        rcu_read_lock();
 203        dev = dev_get_by_index_rcu(net, fq->iif);
 204        if (!dev)
 205                goto out_rcu_unlock;
 206
 207        IP6_INC_STATS_BH(net, __in6_dev_get(dev), IPSTATS_MIB_REASMTIMEOUT);
 208        IP6_INC_STATS_BH(net, __in6_dev_get(dev), IPSTATS_MIB_REASMFAILS);
 209
 210        /* Don't send error if the first segment did not arrive. */
 211        if (!(fq->q.last_in & INET_FRAG_FIRST_IN) || !fq->q.fragments)
 212                goto out_rcu_unlock;
 213
 214        /*
 215           But use as source device on which LAST ARRIVED
 216           segment was received. And do not use fq->dev
 217           pointer directly, device might already disappeared.
 218         */
 219        fq->q.fragments->dev = dev;
 220        icmpv6_send(fq->q.fragments, ICMPV6_TIME_EXCEED, ICMPV6_EXC_FRAGTIME, 0);
 221out_rcu_unlock:
 222        rcu_read_unlock();
 223out:
 224        spin_unlock(&fq->q.lock);
 225        fq_put(fq);
 226}
 227
 228static __inline__ struct frag_queue *
 229fq_find(struct net *net, __be32 id, const struct in6_addr *src, const struct in6_addr *dst)
 230{
 231        struct inet_frag_queue *q;
 232        struct ip6_create_arg arg;
 233        unsigned int hash;
 234
 235        arg.id = id;
 236        arg.user = IP6_DEFRAG_LOCAL_DELIVER;
 237        arg.src = src;
 238        arg.dst = dst;
 239
 240        read_lock(&ip6_frags.lock);
 241        hash = inet6_hash_frag(id, src, dst, ip6_frags.rnd);
 242
 243        q = inet_frag_find(&net->ipv6.frags, &ip6_frags, &arg, hash);
 244        if (q == NULL)
 245                return NULL;
 246
 247        return container_of(q, struct frag_queue, q);
 248}
 249
 250static int ip6_frag_queue(struct frag_queue *fq, struct sk_buff *skb,
 251                           struct frag_hdr *fhdr, int nhoff)
 252{
 253        struct sk_buff *prev, *next;
 254        struct net_device *dev;
 255        int offset, end;
 256        struct net *net = dev_net(skb_dst(skb)->dev);
 257
 258        if (fq->q.last_in & INET_FRAG_COMPLETE)
 259                goto err;
 260
 261        offset = ntohs(fhdr->frag_off) & ~0x7;
 262        end = offset + (ntohs(ipv6_hdr(skb)->payload_len) -
 263                        ((u8 *)(fhdr + 1) - (u8 *)(ipv6_hdr(skb) + 1)));
 264
 265        if ((unsigned int)end > IPV6_MAXPLEN) {
 266                IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
 267                                 IPSTATS_MIB_INHDRERRORS);
 268                icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 269                                  ((u8 *)&fhdr->frag_off -
 270                                   skb_network_header(skb)));
 271                return -1;
 272        }
 273
 274        if (skb->ip_summed == CHECKSUM_COMPLETE) {
 275                const unsigned char *nh = skb_network_header(skb);
 276                skb->csum = csum_sub(skb->csum,
 277                                     csum_partial(nh, (u8 *)(fhdr + 1) - nh,
 278                                                  0));
 279        }
 280
 281        /* Is this the final fragment? */
 282        if (!(fhdr->frag_off & htons(IP6_MF))) {
 283                /* If we already have some bits beyond end
 284                 * or have different end, the segment is corrupted.
 285                 */
 286                if (end < fq->q.len ||
 287                    ((fq->q.last_in & INET_FRAG_LAST_IN) && end != fq->q.len))
 288                        goto err;
 289                fq->q.last_in |= INET_FRAG_LAST_IN;
 290                fq->q.len = end;
 291        } else {
 292                /* Check if the fragment is rounded to 8 bytes.
 293                 * Required by the RFC.
 294                 */
 295                if (end & 0x7) {
 296                        /* RFC2460 says always send parameter problem in
 297                         * this case. -DaveM
 298                         */
 299                        IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
 300                                         IPSTATS_MIB_INHDRERRORS);
 301                        icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 302                                          offsetof(struct ipv6hdr, payload_len));
 303                        return -1;
 304                }
 305                if (end > fq->q.len) {
 306                        /* Some bits beyond end -> corruption. */
 307                        if (fq->q.last_in & INET_FRAG_LAST_IN)
 308                                goto err;
 309                        fq->q.len = end;
 310                }
 311        }
 312
 313        if (end == offset)
 314                goto err;
 315
 316        /* Point into the IP datagram 'data' part. */
 317        if (!pskb_pull(skb, (u8 *) (fhdr + 1) - skb->data))
 318                goto err;
 319
 320        if (pskb_trim_rcsum(skb, end - offset))
 321                goto err;
 322
 323        /* Find out which fragments are in front and at the back of us
 324         * in the chain of fragments so far.  We must know where to put
 325         * this fragment, right?
 326         */
 327        prev = fq->q.fragments_tail;
 328        if (!prev || FRAG6_CB(prev)->offset < offset) {
 329                next = NULL;
 330                goto found;
 331        }
 332        prev = NULL;
 333        for(next = fq->q.fragments; next != NULL; next = next->next) {
 334                if (FRAG6_CB(next)->offset >= offset)
 335                        break;  /* bingo! */
 336                prev = next;
 337        }
 338
 339found:
 340        /* RFC5722, Section 4, amended by Errata ID : 3089
 341         *                          When reassembling an IPv6 datagram, if
 342         *   one or more its constituent fragments is determined to be an
 343         *   overlapping fragment, the entire datagram (and any constituent
 344         *   fragments) MUST be silently discarded.
 345         */
 346
 347        /* Check for overlap with preceding fragment. */
 348        if (prev &&
 349            (FRAG6_CB(prev)->offset + prev->len) > offset)
 350                goto discard_fq;
 351
 352        /* Look for overlap with succeeding segment. */
 353        if (next && FRAG6_CB(next)->offset < end)
 354                goto discard_fq;
 355
 356        FRAG6_CB(skb)->offset = offset;
 357
 358        /* Insert this fragment in the chain of fragments. */
 359        skb->next = next;
 360        if (!next)
 361                fq->q.fragments_tail = skb;
 362        if (prev)
 363                prev->next = skb;
 364        else
 365                fq->q.fragments = skb;
 366
 367        dev = skb->dev;
 368        if (dev) {
 369                fq->iif = dev->ifindex;
 370                skb->dev = NULL;
 371        }
 372        fq->q.stamp = skb->tstamp;
 373        fq->q.meat += skb->len;
 374        atomic_add(skb->truesize, &fq->q.net->mem);
 375
 376        /* The first fragment.
 377         * nhoffset is obtained from the first fragment, of course.
 378         */
 379        if (offset == 0) {
 380                fq->nhoffset = nhoff;
 381                fq->q.last_in |= INET_FRAG_FIRST_IN;
 382        }
 383
 384        if (fq->q.last_in == (INET_FRAG_FIRST_IN | INET_FRAG_LAST_IN) &&
 385            fq->q.meat == fq->q.len)
 386                return ip6_frag_reasm(fq, prev, dev);
 387
 388        write_lock(&ip6_frags.lock);
 389        list_move_tail(&fq->q.lru_list, &fq->q.net->lru_list);
 390        write_unlock(&ip6_frags.lock);
 391        return -1;
 392
 393discard_fq:
 394        fq_kill(fq);
 395err:
 396        IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 397                      IPSTATS_MIB_REASMFAILS);
 398        kfree_skb(skb);
 399        return -1;
 400}
 401
 402/*
 403 *      Check if this packet is complete.
 404 *      Returns NULL on failure by any reason, and pointer
 405 *      to current nexthdr field in reassembled frame.
 406 *
 407 *      It is called with locked fq, and caller must check that
 408 *      queue is eligible for reassembly i.e. it is not COMPLETE,
 409 *      the last and the first frames arrived and all the bits are here.
 410 */
 411static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff *prev,
 412                          struct net_device *dev)
 413{
 414        struct net *net = container_of(fq->q.net, struct net, ipv6.frags);
 415        struct sk_buff *fp, *head = fq->q.fragments;
 416        int    payload_len;
 417        unsigned int nhoff;
 418        int sum_truesize;
 419
 420        fq_kill(fq);
 421
 422        /* Make the one we just received the head. */
 423        if (prev) {
 424                head = prev->next;
 425                fp = skb_clone(head, GFP_ATOMIC);
 426
 427                if (!fp)
 428                        goto out_oom;
 429
 430                fp->next = head->next;
 431                if (!fp->next)
 432                        fq->q.fragments_tail = fp;
 433                prev->next = fp;
 434
 435                skb_morph(head, fq->q.fragments);
 436                head->next = fq->q.fragments->next;
 437
 438                consume_skb(fq->q.fragments);
 439                fq->q.fragments = head;
 440        }
 441
 442        WARN_ON(head == NULL);
 443        WARN_ON(FRAG6_CB(head)->offset != 0);
 444
 445        /* Unfragmented part is taken from the first segment. */
 446        payload_len = ((head->data - skb_network_header(head)) -
 447                       sizeof(struct ipv6hdr) + fq->q.len -
 448                       sizeof(struct frag_hdr));
 449        if (payload_len > IPV6_MAXPLEN)
 450                goto out_oversize;
 451
 452        /* Head of list must not be cloned. */
 453        if (skb_cloned(head) && pskb_expand_head(head, 0, 0, GFP_ATOMIC))
 454                goto out_oom;
 455
 456        /* If the first fragment is fragmented itself, we split
 457         * it to two chunks: the first with data and paged part
 458         * and the second, holding only fragments. */
 459        if (skb_has_frag_list(head)) {
 460                struct sk_buff *clone;
 461                int i, plen = 0;
 462
 463                if ((clone = alloc_skb(0, GFP_ATOMIC)) == NULL)
 464                        goto out_oom;
 465                clone->next = head->next;
 466                head->next = clone;
 467                skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list;
 468                skb_frag_list_init(head);
 469                for (i = 0; i < skb_shinfo(head)->nr_frags; i++)
 470                        plen += skb_frag_size(&skb_shinfo(head)->frags[i]);
 471                clone->len = clone->data_len = head->data_len - plen;
 472                head->data_len -= clone->len;
 473                head->len -= clone->len;
 474                clone->csum = 0;
 475                clone->ip_summed = head->ip_summed;
 476                atomic_add(clone->truesize, &fq->q.net->mem);
 477        }
 478
 479        /* We have to remove fragment header from datagram and to relocate
 480         * header in order to calculate ICV correctly. */
 481        nhoff = fq->nhoffset;
 482        skb_network_header(head)[nhoff] = skb_transport_header(head)[0];
 483        memmove(head->head + sizeof(struct frag_hdr), head->head,
 484                (head->data - head->head) - sizeof(struct frag_hdr));
 485        head->mac_header += sizeof(struct frag_hdr);
 486        head->network_header += sizeof(struct frag_hdr);
 487
 488        skb_reset_transport_header(head);
 489        skb_push(head, head->data - skb_network_header(head));
 490
 491        sum_truesize = head->truesize;
 492        for (fp = head->next; fp;) {
 493                bool headstolen;
 494                int delta;
 495                struct sk_buff *next = fp->next;
 496
 497                sum_truesize += fp->truesize;
 498                if (head->ip_summed != fp->ip_summed)
 499                        head->ip_summed = CHECKSUM_NONE;
 500                else if (head->ip_summed == CHECKSUM_COMPLETE)
 501                        head->csum = csum_add(head->csum, fp->csum);
 502
 503                if (skb_try_coalesce(head, fp, &headstolen, &delta)) {
 504                        kfree_skb_partial(fp, headstolen);
 505                } else {
 506                        if (!skb_shinfo(head)->frag_list)
 507                                skb_shinfo(head)->frag_list = fp;
 508                        head->data_len += fp->len;
 509                        head->len += fp->len;
 510                        head->truesize += fp->truesize;
 511                }
 512                fp = next;
 513        }
 514        atomic_sub(sum_truesize, &fq->q.net->mem);
 515
 516        head->next = NULL;
 517        head->dev = dev;
 518        head->tstamp = fq->q.stamp;
 519        ipv6_hdr(head)->payload_len = htons(payload_len);
 520        IP6CB(head)->nhoff = nhoff;
 521
 522        /* Yes, and fold redundant checksum back. 8) */
 523        if (head->ip_summed == CHECKSUM_COMPLETE)
 524                head->csum = csum_partial(skb_network_header(head),
 525                                          skb_network_header_len(head),
 526                                          head->csum);
 527
 528        rcu_read_lock();
 529        IP6_INC_STATS_BH(net, __in6_dev_get(dev), IPSTATS_MIB_REASMOKS);
 530        rcu_read_unlock();
 531        fq->q.fragments = NULL;
 532        fq->q.fragments_tail = NULL;
 533        return 1;
 534
 535out_oversize:
 536        net_dbg_ratelimited("ip6_frag_reasm: payload len = %d\n", payload_len);
 537        goto out_fail;
 538out_oom:
 539        net_dbg_ratelimited("ip6_frag_reasm: no memory for reassembly\n");
 540out_fail:
 541        rcu_read_lock();
 542        IP6_INC_STATS_BH(net, __in6_dev_get(dev), IPSTATS_MIB_REASMFAILS);
 543        rcu_read_unlock();
 544        return -1;
 545}
 546
 547static int ipv6_frag_rcv(struct sk_buff *skb)
 548{
 549        struct frag_hdr *fhdr;
 550        struct frag_queue *fq;
 551        const struct ipv6hdr *hdr = ipv6_hdr(skb);
 552        struct net *net = dev_net(skb_dst(skb)->dev);
 553
 554        IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_REASMREQDS);
 555
 556        /* Jumbo payload inhibits frag. header */
 557        if (hdr->payload_len==0)
 558                goto fail_hdr;
 559
 560        if (!pskb_may_pull(skb, (skb_transport_offset(skb) +
 561                                 sizeof(struct frag_hdr))))
 562                goto fail_hdr;
 563
 564        hdr = ipv6_hdr(skb);
 565        fhdr = (struct frag_hdr *)skb_transport_header(skb);
 566
 567        if (!(fhdr->frag_off & htons(0xFFF9))) {
 568                /* It is not a fragmented frame */
 569                skb->transport_header += sizeof(struct frag_hdr);
 570                IP6_INC_STATS_BH(net,
 571                                 ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_REASMOKS);
 572
 573                IP6CB(skb)->nhoff = (u8 *)fhdr - skb_network_header(skb);
 574                return 1;
 575        }
 576
 577        if (atomic_read(&net->ipv6.frags.mem) > net->ipv6.frags.high_thresh)
 578                ip6_evictor(net, ip6_dst_idev(skb_dst(skb)));
 579
 580        fq = fq_find(net, fhdr->identification, &hdr->saddr, &hdr->daddr);
 581        if (fq != NULL) {
 582                int ret;
 583
 584                spin_lock(&fq->q.lock);
 585
 586                ret = ip6_frag_queue(fq, skb, fhdr, IP6CB(skb)->nhoff);
 587
 588                spin_unlock(&fq->q.lock);
 589                fq_put(fq);
 590                return ret;
 591        }
 592
 593        IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_REASMFAILS);
 594        kfree_skb(skb);
 595        return -1;
 596
 597fail_hdr:
 598        IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_INHDRERRORS);
 599        icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, skb_network_header_len(skb));
 600        return -1;
 601}
 602
 603static const struct inet6_protocol frag_protocol =
 604{
 605        .handler        =       ipv6_frag_rcv,
 606        .flags          =       INET6_PROTO_NOPOLICY,
 607};
 608
 609#ifdef CONFIG_SYSCTL
 610static struct ctl_table ip6_frags_ns_ctl_table[] = {
 611        {
 612                .procname       = "ip6frag_high_thresh",
 613                .data           = &init_net.ipv6.frags.high_thresh,
 614                .maxlen         = sizeof(int),
 615                .mode           = 0644,
 616                .proc_handler   = proc_dointvec
 617        },
 618        {
 619                .procname       = "ip6frag_low_thresh",
 620                .data           = &init_net.ipv6.frags.low_thresh,
 621                .maxlen         = sizeof(int),
 622                .mode           = 0644,
 623                .proc_handler   = proc_dointvec
 624        },
 625        {
 626                .procname       = "ip6frag_time",
 627                .data           = &init_net.ipv6.frags.timeout,
 628                .maxlen         = sizeof(int),
 629                .mode           = 0644,
 630                .proc_handler   = proc_dointvec_jiffies,
 631        },
 632        { }
 633};
 634
 635static struct ctl_table ip6_frags_ctl_table[] = {
 636        {
 637                .procname       = "ip6frag_secret_interval",
 638                .data           = &ip6_frags.secret_interval,
 639                .maxlen         = sizeof(int),
 640                .mode           = 0644,
 641                .proc_handler   = proc_dointvec_jiffies,
 642        },
 643        { }
 644};
 645
 646static int __net_init ip6_frags_ns_sysctl_register(struct net *net)
 647{
 648        struct ctl_table *table;
 649        struct ctl_table_header *hdr;
 650
 651        table = ip6_frags_ns_ctl_table;
 652        if (!net_eq(net, &init_net)) {
 653                table = kmemdup(table, sizeof(ip6_frags_ns_ctl_table), GFP_KERNEL);
 654                if (table == NULL)
 655                        goto err_alloc;
 656
 657                table[0].data = &net->ipv6.frags.high_thresh;
 658                table[1].data = &net->ipv6.frags.low_thresh;
 659                table[2].data = &net->ipv6.frags.timeout;
 660        }
 661
 662        hdr = register_net_sysctl(net, "net/ipv6", table);
 663        if (hdr == NULL)
 664                goto err_reg;
 665
 666        net->ipv6.sysctl.frags_hdr = hdr;
 667        return 0;
 668
 669err_reg:
 670        if (!net_eq(net, &init_net))
 671                kfree(table);
 672err_alloc:
 673        return -ENOMEM;
 674}
 675
 676static void __net_exit ip6_frags_ns_sysctl_unregister(struct net *net)
 677{
 678        struct ctl_table *table;
 679
 680        table = net->ipv6.sysctl.frags_hdr->ctl_table_arg;
 681        unregister_net_sysctl_table(net->ipv6.sysctl.frags_hdr);
 682        if (!net_eq(net, &init_net))
 683                kfree(table);
 684}
 685
 686static struct ctl_table_header *ip6_ctl_header;
 687
 688static int ip6_frags_sysctl_register(void)
 689{
 690        ip6_ctl_header = register_net_sysctl(&init_net, "net/ipv6",
 691                        ip6_frags_ctl_table);
 692        return ip6_ctl_header == NULL ? -ENOMEM : 0;
 693}
 694
 695static void ip6_frags_sysctl_unregister(void)
 696{
 697        unregister_net_sysctl_table(ip6_ctl_header);
 698}
 699#else
 700static inline int ip6_frags_ns_sysctl_register(struct net *net)
 701{
 702        return 0;
 703}
 704
 705static inline void ip6_frags_ns_sysctl_unregister(struct net *net)
 706{
 707}
 708
 709static inline int ip6_frags_sysctl_register(void)
 710{
 711        return 0;
 712}
 713
 714static inline void ip6_frags_sysctl_unregister(void)
 715{
 716}
 717#endif
 718
 719static int __net_init ipv6_frags_init_net(struct net *net)
 720{
 721        net->ipv6.frags.high_thresh = IPV6_FRAG_HIGH_THRESH;
 722        net->ipv6.frags.low_thresh = IPV6_FRAG_LOW_THRESH;
 723        net->ipv6.frags.timeout = IPV6_FRAG_TIMEOUT;
 724
 725        inet_frags_init_net(&net->ipv6.frags);
 726
 727        return ip6_frags_ns_sysctl_register(net);
 728}
 729
 730static void __net_exit ipv6_frags_exit_net(struct net *net)
 731{
 732        ip6_frags_ns_sysctl_unregister(net);
 733        inet_frags_exit_net(&net->ipv6.frags, &ip6_frags);
 734}
 735
 736static struct pernet_operations ip6_frags_ops = {
 737        .init = ipv6_frags_init_net,
 738        .exit = ipv6_frags_exit_net,
 739};
 740
 741int __init ipv6_frag_init(void)
 742{
 743        int ret;
 744
 745        ret = inet6_add_protocol(&frag_protocol, IPPROTO_FRAGMENT);
 746        if (ret)
 747                goto out;
 748
 749        ret = ip6_frags_sysctl_register();
 750        if (ret)
 751                goto err_sysctl;
 752
 753        ret = register_pernet_subsys(&ip6_frags_ops);
 754        if (ret)
 755                goto err_pernet;
 756
 757        ip6_frags.hashfn = ip6_hashfn;
 758        ip6_frags.constructor = ip6_frag_init;
 759        ip6_frags.destructor = NULL;
 760        ip6_frags.skb_free = NULL;
 761        ip6_frags.qsize = sizeof(struct frag_queue);
 762        ip6_frags.match = ip6_frag_match;
 763        ip6_frags.frag_expire = ip6_frag_expire;
 764        ip6_frags.secret_interval = 10 * 60 * HZ;
 765        inet_frags_init(&ip6_frags);
 766out:
 767        return ret;
 768
 769err_pernet:
 770        ip6_frags_sysctl_unregister();
 771err_sysctl:
 772        inet6_del_protocol(&frag_protocol, IPPROTO_FRAGMENT);
 773        goto out;
 774}
 775
 776void ipv6_frag_exit(void)
 777{
 778        inet_frags_fini(&ip6_frags);
 779        ip6_frags_sysctl_unregister();
 780        unregister_pernet_subsys(&ip6_frags_ops);
 781        inet6_del_protocol(&frag_protocol, IPPROTO_FRAGMENT);
 782}
 783
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