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
  68static struct inet_frags ip6_frags;
  69
  70static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff *prev,
  71                          struct net_device *dev);
  72
  73/*
  74 * callers should be careful not to use the hash value outside the ipfrag_lock
  75 * as doing so could race with ipfrag_hash_rnd being recalculated.
  76 */
  77unsigned int inet6_hash_frag(__be32 id, const struct in6_addr *saddr,
  78                             const struct in6_addr *daddr, u32 rnd)
  79{
  80        u32 c;
  81
  82        c = jhash_3words((__force u32)saddr->s6_addr32[0],
  83                         (__force u32)saddr->s6_addr32[1],
  84                         (__force u32)saddr->s6_addr32[2],
  85                         rnd);
  86
  87        c = jhash_3words((__force u32)saddr->s6_addr32[3],
  88                         (__force u32)daddr->s6_addr32[0],
  89                         (__force u32)daddr->s6_addr32[1],
  90                         c);
  91
  92        c =  jhash_3words((__force u32)daddr->s6_addr32[2],
  93                          (__force u32)daddr->s6_addr32[3],
  94                          (__force u32)id,
  95                          c);
  96
  97        return c & (INETFRAGS_HASHSZ - 1);
  98}
  99EXPORT_SYMBOL_GPL(inet6_hash_frag);
 100
 101static unsigned int ip6_hashfn(struct inet_frag_queue *q)
 102{
 103        struct frag_queue *fq;
 104
 105        fq = container_of(q, struct frag_queue, q);
 106        return inet6_hash_frag(fq->id, &fq->saddr, &fq->daddr, ip6_frags.rnd);
 107}
 108
 109bool ip6_frag_match(struct inet_frag_queue *q, void *a)
 110{
 111        struct frag_queue *fq;
 112        struct ip6_create_arg *arg = a;
 113
 114        fq = container_of(q, struct frag_queue, q);
 115        return  fq->id == arg->id &&
 116                fq->user == arg->user &&
 117                ipv6_addr_equal(&fq->saddr, arg->src) &&
 118                ipv6_addr_equal(&fq->daddr, arg->dst);
 119}
 120EXPORT_SYMBOL(ip6_frag_match);
 121
 122void ip6_frag_init(struct inet_frag_queue *q, void *a)
 123{
 124        struct frag_queue *fq = container_of(q, struct frag_queue, q);
 125        struct ip6_create_arg *arg = a;
 126
 127        fq->id = arg->id;
 128        fq->user = arg->user;
 129        fq->saddr = *arg->src;
 130        fq->daddr = *arg->dst;
 131}
 132EXPORT_SYMBOL(ip6_frag_init);
 133
 134void ip6_expire_frag_queue(struct net *net, struct frag_queue *fq,
 135                           struct inet_frags *frags)
 136{
 137        struct net_device *dev = NULL;
 138
 139        spin_lock(&fq->q.lock);
 140
 141        if (fq->q.last_in & INET_FRAG_COMPLETE)
 142                goto out;
 143
 144        inet_frag_kill(&fq->q, frags);
 145
 146        rcu_read_lock();
 147        dev = dev_get_by_index_rcu(net, fq->iif);
 148        if (!dev)
 149                goto out_rcu_unlock;
 150
 151        IP6_INC_STATS_BH(net, __in6_dev_get(dev), IPSTATS_MIB_REASMTIMEOUT);
 152        IP6_INC_STATS_BH(net, __in6_dev_get(dev), IPSTATS_MIB_REASMFAILS);
 153
 154        /* Don't send error if the first segment did not arrive. */
 155        if (!(fq->q.last_in & INET_FRAG_FIRST_IN) || !fq->q.fragments)
 156                goto out_rcu_unlock;
 157
 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);
 165out_rcu_unlock:
 166        rcu_read_unlock();
 167out:
 168        spin_unlock(&fq->q.lock);
 169        inet_frag_put(&fq->q, frags);
 170}
 171EXPORT_SYMBOL(ip6_expire_frag_queue);
 172
 173static 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
 184static __inline__ struct frag_queue *
 185fq_find(struct net *net, __be32 id, const struct in6_addr *src, const struct in6_addr *dst)
 186{
 187        struct inet_frag_queue *q;
 188        struct ip6_create_arg arg;
 189        unsigned int hash;
 190
 191        arg.id = id;
 192        arg.user = IP6_DEFRAG_LOCAL_DELIVER;
 193        arg.src = src;
 194        arg.dst = dst;
 195
 196        read_lock(&ip6_frags.lock);
 197        hash = inet6_hash_frag(id, src, dst, ip6_frags.rnd);
 198
 199        q = inet_frag_find(&net->ipv6.frags, &ip6_frags, &arg, hash);
 200        if (q == NULL)
 201                return NULL;
 202
 203        return container_of(q, struct frag_queue, q);
 204}
 205
 206static 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
 214        if (fq->q.last_in & INET_FRAG_COMPLETE)
 215                goto err;
 216
 217        offset = ntohs(fhdr->frag_off) & ~0x7;
 218        end = offset + (ntohs(ipv6_hdr(skb)->payload_len) -
 219                        ((u8 *)(fhdr + 1) - (u8 *)(ipv6_hdr(skb) + 1)));
 220
 221        if ((unsigned int)end > IPV6_MAXPLEN) {
 222                IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
 223                                 IPSTATS_MIB_INHDRERRORS);
 224                icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 225                                  ((u8 *)&fhdr->frag_off -
 226                                   skb_network_header(skb)));
 227                return -1;
 228        }
 229
 230        if (skb->ip_summed == CHECKSUM_COMPLETE) {
 231                const unsigned char *nh = skb_network_header(skb);
 232                skb->csum = csum_sub(skb->csum,
 233                                     csum_partial(nh, (u8 *)(fhdr + 1) - nh,
 234                                                  0));
 235        }
 236
 237        /* Is this the final fragment? */
 238        if (!(fhdr->frag_off & htons(IP6_MF))) {
 239                /* If we already have some bits beyond end
 240                 * or have different end, the segment is corrupted.
 241                 */
 242                if (end < fq->q.len ||
 243                    ((fq->q.last_in & INET_FRAG_LAST_IN) && end != fq->q.len))
 244                        goto err;
 245                fq->q.last_in |= INET_FRAG_LAST_IN;
 246                fq->q.len = end;
 247        } else {
 248                /* Check if the fragment is rounded to 8 bytes.
 249                 * Required by the RFC.
 250                 */
 251                if (end & 0x7) {
 252                        /* RFC2460 says always send parameter problem in
 253                         * this case. -DaveM
 254                         */
 255                        IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
 256                                         IPSTATS_MIB_INHDRERRORS);
 257                        icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 258                                          offsetof(struct ipv6hdr, payload_len));
 259                        return -1;
 260                }
 261                if (end > fq->q.len) {
 262                        /* Some bits beyond end -> corruption. */
 263                        if (fq->q.last_in & INET_FRAG_LAST_IN)
 264                                goto err;
 265                        fq->q.len = end;
 266                }
 267        }
 268
 269        if (end == offset)
 270                goto err;
 271
 272        /* Point into the IP datagram 'data' part. */
 273        if (!pskb_pull(skb, (u8 *) (fhdr + 1) - skb->data))
 274                goto err;
 275
 276        if (pskb_trim_rcsum(skb, end - offset))
 277                goto err;
 278
 279        /* Find out which fragments are in front and at the back of us
 280         * in the chain of fragments so far.  We must know where to put
 281         * this fragment, right?
 282         */
 283        prev = fq->q.fragments_tail;
 284        if (!prev || FRAG6_CB(prev)->offset < offset) {
 285                next = NULL;
 286                goto found;
 287        }
 288        prev = NULL;
 289        for(next = fq->q.fragments; next != NULL; next = next->next) {
 290                if (FRAG6_CB(next)->offset >= offset)
 291                        break;  /* bingo! */
 292                prev = next;
 293        }
 294
 295found:
 296        /* RFC5722, Section 4, amended by Errata ID : 3089
 297         *                          When reassembling an IPv6 datagram, if
 298         *   one or more its constituent fragments is determined to be an
 299         *   overlapping fragment, the entire datagram (and any constituent
 300         *   fragments) MUST be silently discarded.
 301         */
 302
 303        /* Check for overlap with preceding fragment. */
 304        if (prev &&
 305            (FRAG6_CB(prev)->offset + prev->len) > offset)
 306                goto discard_fq;
 307
 308        /* Look for overlap with succeeding segment. */
 309        if (next && FRAG6_CB(next)->offset < end)
 310                goto discard_fq;
 311
 312        FRAG6_CB(skb)->offset = offset;
 313
 314        /* Insert this fragment in the chain of fragments. */
 315        skb->next = next;
 316        if (!next)
 317                fq->q.fragments_tail = skb;
 318        if (prev)
 319                prev->next = skb;
 320        else
 321                fq->q.fragments = skb;
 322
 323        dev = skb->dev;
 324        if (dev) {
 325                fq->iif = dev->ifindex;
 326                skb->dev = NULL;
 327        }
 328        fq->q.stamp = skb->tstamp;
 329        fq->q.meat += skb->len;
 330        atomic_add(skb->truesize, &fq->q.net->mem);
 331
 332        /* The first fragment.
 333         * nhoffset is obtained from the first fragment, of course.
 334         */
 335        if (offset == 0) {
 336                fq->nhoffset = nhoff;
 337                fq->q.last_in |= INET_FRAG_FIRST_IN;
 338        }
 339
 340        if (fq->q.last_in == (INET_FRAG_FIRST_IN | INET_FRAG_LAST_IN) &&
 341            fq->q.meat == fq->q.len)
 342                return ip6_frag_reasm(fq, prev, dev);
 343
 344        write_lock(&ip6_frags.lock);
 345        list_move_tail(&fq->q.lru_list, &fq->q.net->lru_list);
 346        write_unlock(&ip6_frags.lock);
 347        return -1;
 348
 349discard_fq:
 350        inet_frag_kill(&fq->q, &ip6_frags);
 351err:
 352        IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 353                      IPSTATS_MIB_REASMFAILS);
 354        kfree_skb(skb);
 355        return -1;
 356}
 357
 358/*
 359 *      Check if this packet is complete.
 360 *      Returns NULL on failure by any reason, and pointer
 361 *      to current nexthdr field in reassembled frame.
 362 *
 363 *      It is called with locked fq, and caller must check that
 364 *      queue is eligible for reassembly i.e. it is not COMPLETE,
 365 *      the last and the first frames arrived and all the bits are here.
 366 */
 367static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff *prev,
 368                          struct net_device *dev)
 369{
 370        struct net *net = container_of(fq->q.net, struct net, ipv6.frags);
 371        struct sk_buff *fp, *head = fq->q.fragments;
 372        int    payload_len;
 373        unsigned int nhoff;
 374        int sum_truesize;
 375
 376        inet_frag_kill(&fq->q, &ip6_frags);
 377
 378        /* Make the one we just received the head. */
 379        if (prev) {
 380                head = prev->next;
 381                fp = skb_clone(head, GFP_ATOMIC);
 382
 383                if (!fp)
 384                        goto out_oom;
 385
 386                fp->next = head->next;
 387                if (!fp->next)
 388                        fq->q.fragments_tail = fp;
 389                prev->next = fp;
 390
 391                skb_morph(head, fq->q.fragments);
 392                head->next = fq->q.fragments->next;
 393
 394                consume_skb(fq->q.fragments);
 395                fq->q.fragments = head;
 396        }
 397
 398        WARN_ON(head == NULL);
 399        WARN_ON(FRAG6_CB(head)->offset != 0);
 400
 401        /* Unfragmented part is taken from the first segment. */
 402        payload_len = ((head->data - skb_network_header(head)) -
 403                       sizeof(struct ipv6hdr) + fq->q.len -
 404                       sizeof(struct frag_hdr));
 405        if (payload_len > IPV6_MAXPLEN)
 406                goto out_oversize;
 407
 408        /* Head of list must not be cloned. */
 409        if (skb_cloned(head) && pskb_expand_head(head, 0, 0, GFP_ATOMIC))
 410                goto out_oom;
 411
 412        /* If the first fragment is fragmented itself, we split
 413         * it to two chunks: the first with data and paged part
 414         * and the second, holding only fragments. */
 415        if (skb_has_frag_list(head)) {
 416                struct sk_buff *clone;
 417                int i, plen = 0;
 418
 419                if ((clone = alloc_skb(0, GFP_ATOMIC)) == NULL)
 420                        goto out_oom;
 421                clone->next = head->next;
 422                head->next = clone;
 423                skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list;
 424                skb_frag_list_init(head);
 425                for (i = 0; i < skb_shinfo(head)->nr_frags; i++)
 426                        plen += skb_frag_size(&skb_shinfo(head)->frags[i]);
 427                clone->len = clone->data_len = head->data_len - plen;
 428                head->data_len -= clone->len;
 429                head->len -= clone->len;
 430                clone->csum = 0;
 431                clone->ip_summed = head->ip_summed;
 432                atomic_add(clone->truesize, &fq->q.net->mem);
 433        }
 434
 435        /* We have to remove fragment header from datagram and to relocate
 436         * header in order to calculate ICV correctly. */
 437        nhoff = fq->nhoffset;
 438        skb_network_header(head)[nhoff] = skb_transport_header(head)[0];
 439        memmove(head->head + sizeof(struct frag_hdr), head->head,
 440                (head->data - head->head) - sizeof(struct frag_hdr));
 441        head->mac_header += sizeof(struct frag_hdr);
 442        head->network_header += sizeof(struct frag_hdr);
 443
 444        skb_reset_transport_header(head);
 445        skb_push(head, head->data - skb_network_header(head));
 446
 447        sum_truesize = head->truesize;
 448        for (fp = head->next; fp;) {
 449                bool headstolen;
 450                int delta;
 451                struct sk_buff *next = fp->next;
 452
 453                sum_truesize += fp->truesize;
 454                if (head->ip_summed != fp->ip_summed)
 455                        head->ip_summed = CHECKSUM_NONE;
 456                else if (head->ip_summed == CHECKSUM_COMPLETE)
 457                        head->csum = csum_add(head->csum, fp->csum);
 458
 459                if (skb_try_coalesce(head, fp, &headstolen, &delta)) {
 460                        kfree_skb_partial(fp, headstolen);
 461                } else {
 462                        if (!skb_shinfo(head)->frag_list)
 463                                skb_shinfo(head)->frag_list = fp;
 464                        head->data_len += fp->len;
 465                        head->len += fp->len;
 466                        head->truesize += fp->truesize;
 467                }
 468                fp = next;
 469        }
 470        atomic_sub(sum_truesize, &fq->q.net->mem);
 471
 472        head->next = NULL;
 473        head->dev = dev;
 474        head->tstamp = fq->q.stamp;
 475        ipv6_hdr(head)->payload_len = htons(payload_len);
 476        IP6CB(head)->nhoff = nhoff;
 477
 478        /* Yes, and fold redundant checksum back. 8) */
 479        if (head->ip_summed == CHECKSUM_COMPLETE)
 480                head->csum = csum_partial(skb_network_header(head),
 481                                          skb_network_header_len(head),
 482                                          head->csum);
 483
 484        rcu_read_lock();
 485        IP6_INC_STATS_BH(net, __in6_dev_get(dev), IPSTATS_MIB_REASMOKS);
 486        rcu_read_unlock();
 487        fq->q.fragments = NULL;
 488        fq->q.fragments_tail = NULL;
 489        return 1;
 490
 491out_oversize:
 492        net_dbg_ratelimited("ip6_frag_reasm: payload len = %d\n", payload_len);
 493        goto out_fail;
 494out_oom:
 495        net_dbg_ratelimited("ip6_frag_reasm: no memory for reassembly\n");
 496out_fail:
 497        rcu_read_lock();
 498        IP6_INC_STATS_BH(net, __in6_dev_get(dev), IPSTATS_MIB_REASMFAILS);
 499        rcu_read_unlock();
 500        return -1;
 501}
 502
 503static int ipv6_frag_rcv(struct sk_buff *skb)
 504{
 505        struct frag_hdr *fhdr;
 506        struct frag_queue *fq;
 507        const struct ipv6hdr *hdr = ipv6_hdr(skb);
 508        struct net *net = dev_net(skb_dst(skb)->dev);
 509        int evicted;
 510
 511        IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_REASMREQDS);
 512
 513        /* Jumbo payload inhibits frag. header */
 514        if (hdr->payload_len==0)
 515                goto fail_hdr;
 516
 517        if (!pskb_may_pull(skb, (skb_transport_offset(skb) +
 518                                 sizeof(struct frag_hdr))))
 519                goto fail_hdr;
 520
 521        hdr = ipv6_hdr(skb);
 522        fhdr = (struct frag_hdr *)skb_transport_header(skb);
 523
 524        if (!(fhdr->frag_off & htons(0xFFF9))) {
 525                /* It is not a fragmented frame */
 526                skb->transport_header += sizeof(struct frag_hdr);
 527                IP6_INC_STATS_BH(net,
 528                                 ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_REASMOKS);
 529
 530                IP6CB(skb)->nhoff = (u8 *)fhdr - skb_network_header(skb);
 531                return 1;
 532        }
 533
 534        evicted = inet_frag_evictor(&net->ipv6.frags, &ip6_frags, false);
 535        if (evicted)
 536                IP6_ADD_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
 537                                 IPSTATS_MIB_REASMFAILS, evicted);
 538
 539        fq = fq_find(net, fhdr->identification, &hdr->saddr, &hdr->daddr);
 540        if (fq != NULL) {
 541                int ret;
 542
 543                spin_lock(&fq->q.lock);
 544
 545                ret = ip6_frag_queue(fq, skb, fhdr, IP6CB(skb)->nhoff);
 546
 547                spin_unlock(&fq->q.lock);
 548                inet_frag_put(&fq->q, &ip6_frags);
 549                return ret;
 550        }
 551
 552        IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_REASMFAILS);
 553        kfree_skb(skb);
 554        return -1;
 555
 556fail_hdr:
 557        IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_INHDRERRORS);
 558        icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, skb_network_header_len(skb));
 559        return -1;
 560}
 561
 562static const struct inet6_protocol frag_protocol =
 563{
 564        .handler        =       ipv6_frag_rcv,
 565        .flags          =       INET6_PROTO_NOPOLICY,
 566};
 567
 568#ifdef CONFIG_SYSCTL
 569static struct ctl_table ip6_frags_ns_ctl_table[] = {
 570        {
 571                .procname       = "ip6frag_high_thresh",
 572                .data           = &init_net.ipv6.frags.high_thresh,
 573                .maxlen         = sizeof(int),
 574                .mode           = 0644,
 575                .proc_handler   = proc_dointvec
 576        },
 577        {
 578                .procname       = "ip6frag_low_thresh",
 579                .data           = &init_net.ipv6.frags.low_thresh,
 580                .maxlen         = sizeof(int),
 581                .mode           = 0644,
 582                .proc_handler   = proc_dointvec
 583        },
 584        {
 585                .procname       = "ip6frag_time",
 586                .data           = &init_net.ipv6.frags.timeout,
 587                .maxlen         = sizeof(int),
 588                .mode           = 0644,
 589                .proc_handler   = proc_dointvec_jiffies,
 590        },
 591        { }
 592};
 593
 594static struct ctl_table ip6_frags_ctl_table[] = {
 595        {
 596                .procname       = "ip6frag_secret_interval",
 597                .data           = &ip6_frags.secret_interval,
 598                .maxlen         = sizeof(int),
 599                .mode           = 0644,
 600                .proc_handler   = proc_dointvec_jiffies,
 601        },
 602        { }
 603};
 604
 605static int __net_init ip6_frags_ns_sysctl_register(struct net *net)
 606{
 607        struct ctl_table *table;
 608        struct ctl_table_header *hdr;
 609
 610        table = ip6_frags_ns_ctl_table;
 611        if (!net_eq(net, &init_net)) {
 612                table = kmemdup(table, sizeof(ip6_frags_ns_ctl_table), GFP_KERNEL);
 613                if (table == NULL)
 614                        goto err_alloc;
 615
 616                table[0].data = &net->ipv6.frags.high_thresh;
 617                table[1].data = &net->ipv6.frags.low_thresh;
 618                table[2].data = &net->ipv6.frags.timeout;
 619        }
 620
 621        hdr = register_net_sysctl(net, "net/ipv6", table);
 622        if (hdr == NULL)
 623                goto err_reg;
 624
 625        net->ipv6.sysctl.frags_hdr = hdr;
 626        return 0;
 627
 628err_reg:
 629        if (!net_eq(net, &init_net))
 630                kfree(table);
 631err_alloc:
 632        return -ENOMEM;
 633}
 634
 635static void __net_exit ip6_frags_ns_sysctl_unregister(struct net *net)
 636{
 637        struct ctl_table *table;
 638
 639        table = net->ipv6.sysctl.frags_hdr->ctl_table_arg;
 640        unregister_net_sysctl_table(net->ipv6.sysctl.frags_hdr);
 641        if (!net_eq(net, &init_net))
 642                kfree(table);
 643}
 644
 645static struct ctl_table_header *ip6_ctl_header;
 646
 647static int ip6_frags_sysctl_register(void)
 648{
 649        ip6_ctl_header = register_net_sysctl(&init_net, "net/ipv6",
 650                        ip6_frags_ctl_table);
 651        return ip6_ctl_header == NULL ? -ENOMEM : 0;
 652}
 653
 654static void ip6_frags_sysctl_unregister(void)
 655{
 656        unregister_net_sysctl_table(ip6_ctl_header);
 657}
 658#else
 659static inline int ip6_frags_ns_sysctl_register(struct net *net)
 660{
 661        return 0;
 662}
 663
 664static inline void ip6_frags_ns_sysctl_unregister(struct net *net)
 665{
 666}
 667
 668static inline int ip6_frags_sysctl_register(void)
 669{
 670        return 0;
 671}
 672
 673static inline void ip6_frags_sysctl_unregister(void)
 674{
 675}
 676#endif
 677
 678static int __net_init ipv6_frags_init_net(struct net *net)
 679{
 680        net->ipv6.frags.high_thresh = IPV6_FRAG_HIGH_THRESH;
 681        net->ipv6.frags.low_thresh = IPV6_FRAG_LOW_THRESH;
 682        net->ipv6.frags.timeout = IPV6_FRAG_TIMEOUT;
 683
 684        inet_frags_init_net(&net->ipv6.frags);
 685
 686        return ip6_frags_ns_sysctl_register(net);
 687}
 688
 689static void __net_exit ipv6_frags_exit_net(struct net *net)
 690{
 691        ip6_frags_ns_sysctl_unregister(net);
 692        inet_frags_exit_net(&net->ipv6.frags, &ip6_frags);
 693}
 694
 695static struct pernet_operations ip6_frags_ops = {
 696        .init = ipv6_frags_init_net,
 697        .exit = ipv6_frags_exit_net,
 698};
 699
 700int __init ipv6_frag_init(void)
 701{
 702        int ret;
 703
 704        ret = inet6_add_protocol(&frag_protocol, IPPROTO_FRAGMENT);
 705        if (ret)
 706                goto out;
 707
 708        ret = ip6_frags_sysctl_register();
 709        if (ret)
 710                goto err_sysctl;
 711
 712        ret = register_pernet_subsys(&ip6_frags_ops);
 713        if (ret)
 714                goto err_pernet;
 715
 716        ip6_frags.hashfn = ip6_hashfn;
 717        ip6_frags.constructor = ip6_frag_init;
 718        ip6_frags.destructor = NULL;
 719        ip6_frags.skb_free = NULL;
 720        ip6_frags.qsize = sizeof(struct frag_queue);
 721        ip6_frags.match = ip6_frag_match;
 722        ip6_frags.frag_expire = ip6_frag_expire;
 723        ip6_frags.secret_interval = 10 * 60 * HZ;
 724        inet_frags_init(&ip6_frags);
 725out:
 726        return ret;
 727
 728err_pernet:
 729        ip6_frags_sysctl_unregister();
 730err_sysctl:
 731        inet6_del_protocol(&frag_protocol, IPPROTO_FRAGMENT);
 732        goto out;
 733}
 734
 735void ipv6_frag_exit(void)
 736{
 737        inet_frags_fini(&ip6_frags);
 738        ip6_frags_sysctl_unregister();
 739        unregister_pernet_subsys(&ip6_frags_ops);
 740        inet6_del_protocol(&frag_protocol, IPPROTO_FRAGMENT);
 741}
 742
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