net/ipv6/icmp.c

   1 /*
   2  *      Internet Control Message Protocol (ICMPv6)
   3  *      Linux INET6 implementation
   4  *
   5  *      Authors:
   6  *      Pedro Roque             <roque@di.fc.ul.pt>
   7  *
   8  *      $Id: icmp.c,v 1.38 2002/02/08 03:57:19 davem Exp $
   9  *
  10  *      Based on net/ipv4/icmp.c
  11  *
  12  *      RFC 1885
  13  *
  14  *      This program is free software; you can redistribute it and/or
  15  *      modify it under the terms of the GNU General Public License
  16  *      as published by the Free Software Foundation; either version
  17  *      2 of the License, or (at your option) any later version.
  18  */
  19
  20 /*
  21  *      Changes:
  22  *
  23  *      Andi Kleen              :       exception handling
  24  *      Andi Kleen                      add rate limits. never reply to a icmp.
  25  *                                      add more length checks and other fixes.
  26  *      yoshfuji                :       ensure to sent parameter problem for
  27  *                                      fragments.
  28  *      YOSHIFUJI Hideaki @USAGI:       added sysctl for icmp rate limit.
  29  *      Randy Dunlap and
  30  *      YOSHIFUJI Hideaki @USAGI:       Per-interface statistics support
  31  *      Kazunori MIYAZAWA @USAGI:       change output process to use ip6_append_data
  32  */
  33
  34 #include <linux/module.h>
  35 #include <linux/errno.h>
  36 #include <linux/types.h>
  37 #include <linux/socket.h>
  38 #include <linux/in.h>
  39 #include <linux/kernel.h>
  40 #include <linux/sockios.h>
  41 #include <linux/net.h>
  42 #include <linux/skbuff.h>
  43 #include <linux/init.h>
  44 #include <linux/netfilter.h>
  45
  46 #ifdef CONFIG_SYSCTL
  47 #include <linux/sysctl.h>
  48 #endif
  49
  50 #include <linux/inet.h>
  51 #include <linux/netdevice.h>
  52 #include <linux/icmpv6.h>
  53
  54 #include <net/ip.h>
  55 #include <net/sock.h>
  56
  57 #include <net/ipv6.h>
  58 #include <net/ip6_checksum.h>
  59 #include <net/protocol.h>
  60 #include <net/raw.h>
  61 #include <net/rawv6.h>
  62 #include <net/transp_v6.h>
  63 #include <net/ip6_route.h>
  64 #include <net/addrconf.h>
  65 #include <net/icmp.h>
  66
  67 #include <asm/uaccess.h>
  68 #include <asm/system.h>
  69
  70 DEFINE_SNMP_STAT(struct icmpv6_mib, icmpv6_statistics) __read_mostly;
  71 EXPORT_SYMBOL(icmpv6_statistics);
  72 DEFINE_SNMP_STAT(struct icmpv6msg_mib, icmpv6msg_statistics) __read_mostly;
  73 EXPORT_SYMBOL(icmpv6msg_statistics);
  74
  75 /*
  76  *      The ICMP socket(s). This is the most convenient way to flow control
  77  *      our ICMP output as well as maintain a clean interface throughout
  78  *      all layers. All Socketless IP sends will soon be gone.
  79  *
  80  *      On SMP we have one ICMP socket per-cpu.
  81  */
  82 static DEFINE_PER_CPU(struct socket *, __icmpv6_socket) = NULL;
  83 #define icmpv6_socket   __get_cpu_var(__icmpv6_socket)
  84
  85 static int icmpv6_rcv(struct sk_buff **pskb);
  86
  87 static struct inet6_protocol icmpv6_protocol = {
  88         .handler        =       icmpv6_rcv,
  89         .flags          =       INET6_PROTO_FINAL,
  90 };
  91
  92 static __inline__ int icmpv6_xmit_lock(void)
  93 {
  94         local_bh_disable();
  95
  96         if (unlikely(!spin_trylock(&icmpv6_socket->sk->sk_lock.slock))) {
  97                 /* This can happen if the output path (f.e. SIT or
  98                  * ip6ip6 tunnel) signals dst_link_failure() for an
  99                  * outgoing ICMP6 packet.
 100                  */
 101                 local_bh_enable();
 102                 return 1;
 103         }
 104         return 0;
 105 }
 106
 107 static __inline__ void icmpv6_xmit_unlock(void)
 108 {
 109         spin_unlock_bh(&icmpv6_socket->sk->sk_lock.slock);
 110 }
 111
 112 /*
 113  * Slightly more convenient version of icmpv6_send.
 114  */
 115 void icmpv6_param_prob(struct sk_buff *skb, int code, int pos)
 116 {
 117         icmpv6_send(skb, ICMPV6_PARAMPROB, code, pos, skb->dev);
 118         kfree_skb(skb);
 119 }
 120
 121 /*
 122  * Figure out, may we reply to this packet with icmp error.
 123  *
 124  * We do not reply, if:
 125  *      - it was icmp error message.
 126  *      - it is truncated, so that it is known, that protocol is ICMPV6
 127  *        (i.e. in the middle of some exthdr)
 128  *
 129  *      --ANK (980726)
 130  */
 131
 132 static int is_ineligible(struct sk_buff *skb)
 133 {
 134         int ptr = (u8 *)(ipv6_hdr(skb) + 1) - skb->data;
 135         int len = skb->len - ptr;
 136         __u8 nexthdr = ipv6_hdr(skb)->nexthdr;
 137
 138         if (len < 0)
 139                 return 1;
 140
 141         ptr = ipv6_skip_exthdr(skb, ptr, &nexthdr);
 142         if (ptr < 0)
 143                 return 0;
 144         if (nexthdr == IPPROTO_ICMPV6) {
 145                 u8 _type, *tp;
 146                 tp = skb_header_pointer(skb,
 147                         ptr+offsetof(struct icmp6hdr, icmp6_type),
 148                         sizeof(_type), &_type);
 149                 if (tp == NULL ||
 150                     !(*tp & ICMPV6_INFOMSG_MASK))
 151                         return 1;
 152         }
 153         return 0;
 154 }
 155
 156 static int sysctl_icmpv6_time __read_mostly = 1*HZ;
 157
 158 /*
 159  * Check the ICMP output rate limit
 160  */
 161 static inline int icmpv6_xrlim_allow(struct sock *sk, int type,
 162                                      struct flowi *fl)
 163 {
 164         struct dst_entry *dst;
 165         int res = 0;
 166
 167         /* Informational messages are not limited. */
 168         if (type & ICMPV6_INFOMSG_MASK)
 169                 return 1;
 170
 171         /* Do not limit pmtu discovery, it would break it. */
 172         if (type == ICMPV6_PKT_TOOBIG)
 173                 return 1;
 174
 175         /*
 176          * Look up the output route.
 177          * XXX: perhaps the expire for routing entries cloned by
 178          * this lookup should be more aggressive (not longer than timeout).
 179          */
 180         dst = ip6_route_output(sk, fl);
 181         if (dst->error) {
 182                 IP6_INC_STATS(ip6_dst_idev(dst),
 183                               IPSTATS_MIB_OUTNOROUTES);
 184         } else if (dst->dev && (dst->dev->flags&IFF_LOOPBACK)) {
 185                 res = 1;
 186         } else {
 187                 struct rt6_info *rt = (struct rt6_info *)dst;
 188                 int tmo = sysctl_icmpv6_time;
 189
 190                 /* Give more bandwidth to wider prefixes. */
 191                 if (rt->rt6i_dst.plen < 128)
 192                         tmo >>= ((128 - rt->rt6i_dst.plen)>>5);
 193
 194                 res = xrlim_allow(dst, tmo);
 195         }
 196         dst_release(dst);
 197         return res;
 198 }
 199
 200 /*
 201  *      an inline helper for the "simple" if statement below
 202  *      checks if parameter problem report is caused by an
 203  *      unrecognized IPv6 option that has the Option Type
 204  *      highest-order two bits set to 10
 205  */
 206
 207 static __inline__ int opt_unrec(struct sk_buff *skb, __u32 offset)
 208 {
 209         u8 _optval, *op;
 210
 211         offset += skb_network_offset(skb);
 212         op = skb_header_pointer(skb, offset, sizeof(_optval), &_optval);
 213         if (op == NULL)
 214                 return 1;
 215         return (*op & 0xC0) == 0x80;
 216 }
 217
 218 static int icmpv6_push_pending_frames(struct sock *sk, struct flowi *fl, struct icmp6hdr *thdr, int len)
 219 {
 220         struct sk_buff *skb;
 221         struct icmp6hdr *icmp6h;
 222         int err = 0;
 223
 224         if ((skb = skb_peek(&sk->sk_write_queue)) == NULL)
 225                 goto out;
 226
 227         icmp6h = icmp6_hdr(skb);
 228         memcpy(icmp6h, thdr, sizeof(struct icmp6hdr));
 229         icmp6h->icmp6_cksum = 0;
 230
 231         if (skb_queue_len(&sk->sk_write_queue) == 1) {
 232                 skb->csum = csum_partial((char *)icmp6h,
 233                                         sizeof(struct icmp6hdr), skb->csum);
 234                 icmp6h->icmp6_cksum = csum_ipv6_magic(&fl->fl6_src,
 235                                                       &fl->fl6_dst,
 236                                                       len, fl->proto,
 237                                                       skb->csum);
 238         } else {
 239                 __wsum tmp_csum = 0;
 240
 241                 skb_queue_walk(&sk->sk_write_queue, skb) {
 242                         tmp_csum = csum_add(tmp_csum, skb->csum);
 243                 }
 244
 245                 tmp_csum = csum_partial((char *)icmp6h,
 246                                         sizeof(struct icmp6hdr), tmp_csum);
 247                 icmp6h->icmp6_cksum = csum_ipv6_magic(&fl->fl6_src,
 248                                                       &fl->fl6_dst,
 249                                                       len, fl->proto,
 250                                                       tmp_csum);
 251         }
 252         ip6_push_pending_frames(sk);
 253 out:
 254         return err;
 255 }
 256
 257 struct icmpv6_msg {
 258         struct sk_buff  *skb;
 259         int             offset;
 260         uint8_t         type;
 261 };
 262
 263 static int icmpv6_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb)
 264 {
 265         struct icmpv6_msg *msg = (struct icmpv6_msg *) from;
 266         struct sk_buff *org_skb = msg->skb;
 267         __wsum csum = 0;
 268
 269         csum = skb_copy_and_csum_bits(org_skb, msg->offset + offset,
 270                                       to, len, csum);
 271         skb->csum = csum_block_add(skb->csum, csum, odd);
 272         if (!(msg->type & ICMPV6_INFOMSG_MASK))
 273                 nf_ct_attach(skb, org_skb);
 274         return 0;
 275 }
 276
 277 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
 278 static void mip6_addr_swap(struct sk_buff *skb)
 279 {
 280         struct ipv6hdr *iph = ipv6_hdr(skb);
 281         struct inet6_skb_parm *opt = IP6CB(skb);
 282         struct ipv6_destopt_hao *hao;
 283         struct in6_addr tmp;
 284         int off;
 285
 286         if (opt->dsthao) {
 287                 off = ipv6_find_tlv(skb, opt->dsthao, IPV6_TLV_HAO);
 288                 if (likely(off >= 0)) {
 289                         hao = (struct ipv6_destopt_hao *)
 290                                         (skb_network_header(skb) + off);
 291                         ipv6_addr_copy(&tmp, &iph->saddr);
 292                         ipv6_addr_copy(&iph->saddr, &hao->addr);
 293                         ipv6_addr_copy(&hao->addr, &tmp);
 294                 }
 295         }
 296 }
 297 #else
 298 static inline void mip6_addr_swap(struct sk_buff *skb) {}
 299 #endif
 300
 301 /*
 302  *      Send an ICMP message in response to a packet in error
 303  */
 304 void icmpv6_send(struct sk_buff *skb, int type, int code, __u32 info,
 305                  struct net_device *dev)
 306 {
 307         struct inet6_dev *idev = NULL;
 308         struct ipv6hdr *hdr = ipv6_hdr(skb);
 309         struct sock *sk;
 310         struct ipv6_pinfo *np;
 311         struct in6_addr *saddr = NULL;
 312         struct dst_entry *dst;
 313         struct icmp6hdr tmp_hdr;
 314         struct flowi fl;
 315         struct icmpv6_msg msg;
 316         int iif = 0;
 317         int addr_type = 0;
 318         int len;
 319         int hlimit, tclass;
 320         int err = 0;
 321
 322         if ((u8 *)hdr < skb->head ||
 323             (skb->network_header + sizeof(*hdr)) > skb->tail)
 324                 return;
 325
 326         /*
 327          *      Make sure we respect the rules
 328          *      i.e. RFC 1885 2.4(e)
 329          *      Rule (e.1) is enforced by not using icmpv6_send
 330          *      in any code that processes icmp errors.
 331          */
 332         addr_type = ipv6_addr_type(&hdr->daddr);
 333
 334         if (ipv6_chk_addr(&hdr->daddr, skb->dev, 0))
 335                 saddr = &hdr->daddr;
 336
 337         /*
 338          *      Dest addr check
 339          */
 340
 341         if ((addr_type & IPV6_ADDR_MULTICAST || skb->pkt_type != PACKET_HOST)) {
 342                 if (type != ICMPV6_PKT_TOOBIG &&
 343                     !(type == ICMPV6_PARAMPROB &&
 344                       code == ICMPV6_UNK_OPTION &&
 345                       (opt_unrec(skb, info))))
 346                         return;
 347
 348                 saddr = NULL;
 349         }
 350
 351         addr_type = ipv6_addr_type(&hdr->saddr);
 352
 353         /*
 354          *      Source addr check
 355          */
 356
 357         if (addr_type & IPV6_ADDR_LINKLOCAL)
 358                 iif = skb->dev->ifindex;
 359
 360         /*
 361          *      Must not send error if the source does not uniquely
 362          *      identify a single node (RFC2463 Section 2.4).
 363          *      We check unspecified / multicast addresses here,
 364          *      and anycast addresses will be checked later.
 365          */
 366         if ((addr_type == IPV6_ADDR_ANY) || (addr_type & IPV6_ADDR_MULTICAST)) {
 367                 LIMIT_NETDEBUG(KERN_DEBUG "icmpv6_send: addr_any/mcast source\n");
 368                 return;
 369         }
 370
 371         /*
 372          *      Never answer to a ICMP packet.
 373          */
 374         if (is_ineligible(skb)) {
 375                 LIMIT_NETDEBUG(KERN_DEBUG "icmpv6_send: no reply to icmp error\n");
 376                 return;
 377         }
 378
 379         mip6_addr_swap(skb);
 380
 381         memset(&fl, 0, sizeof(fl));
 382         fl.proto = IPPROTO_ICMPV6;
 383         ipv6_addr_copy(&fl.fl6_dst, &hdr->saddr);
 384         if (saddr)
 385                 ipv6_addr_copy(&fl.fl6_src, saddr);
 386         fl.oif = iif;
 387         fl.fl_icmp_type = type;
 388         fl.fl_icmp_code = code;
 389         security_skb_classify_flow(skb, &fl);
 390
 391         if (icmpv6_xmit_lock())
 392                 return;
 393
 394         sk = icmpv6_socket->sk;
 395         np = inet6_sk(sk);
 396
 397         if (!icmpv6_xrlim_allow(sk, type, &fl))
 398                 goto out;
 399
 400         tmp_hdr.icmp6_type = type;
 401         tmp_hdr.icmp6_code = code;
 402         tmp_hdr.icmp6_cksum = 0;
 403         tmp_hdr.icmp6_pointer = htonl(info);
 404
 405         if (!fl.oif && ipv6_addr_is_multicast(&fl.fl6_dst))
 406                 fl.oif = np->mcast_oif;
 407
 408         err = ip6_dst_lookup(sk, &dst, &fl);
 409         if (err)
 410                 goto out;
 411
 412         /*
 413          * We won't send icmp if the destination is known
 414          * anycast.
 415          */
 416         if (((struct rt6_info *)dst)->rt6i_flags & RTF_ANYCAST) {
 417                 LIMIT_NETDEBUG(KERN_DEBUG "icmpv6_send: acast source\n");
 418                 goto out_dst_release;
 419         }
 420
 421         if ((err = xfrm_lookup(&dst, &fl, sk, 0)) < 0)
 422                 goto out;
 423
 424         if (ipv6_addr_is_multicast(&fl.fl6_dst))
 425                 hlimit = np->mcast_hops;
 426         else
 427                 hlimit = np->hop_limit;
 428         if (hlimit < 0)
 429                 hlimit = dst_metric(dst, RTAX_HOPLIMIT);
 430         if (hlimit < 0)
 431                 hlimit = ipv6_get_hoplimit(dst->dev);
 432
 433         tclass = np->tclass;
 434         if (tclass < 0)
 435                 tclass = 0;
 436
 437         msg.skb = skb;
 438         msg.offset = skb_network_offset(skb);
 439         msg.type = type;
 440
 441         len = skb->len - msg.offset;
 442         len = min_t(unsigned int, len, IPV6_MIN_MTU - sizeof(struct ipv6hdr) -sizeof(struct icmp6hdr));
 443         if (len < 0) {
 444                 LIMIT_NETDEBUG(KERN_DEBUG "icmp: len problem\n");
 445                 goto out_dst_release;
 446         }
 447
 448         idev = in6_dev_get(skb->dev);
 449
 450         err = ip6_append_data(sk, icmpv6_getfrag, &msg,
 451                               len + sizeof(struct icmp6hdr),
 452                               sizeof(struct icmp6hdr),
 453                               hlimit, tclass, NULL, &fl, (struct rt6_info*)dst,
 454                               MSG_DONTWAIT);
 455         if (err) {
 456                 ip6_flush_pending_frames(sk);
 457                 goto out_put;
 458         }
 459         err = icmpv6_push_pending_frames(sk, &fl, &tmp_hdr, len + sizeof(struct icmp6hdr));
 460
 461         ICMP6_INC_STATS_BH(idev, ICMP6_MIB_OUTMSGS);
 462
 463 out_put:
 464         if (likely(idev != NULL))
 465                 in6_dev_put(idev);
 466 out_dst_release:
 467         dst_release(dst);
 468 out:
 469         icmpv6_xmit_unlock();
 470 }
 471
 472 EXPORT_SYMBOL(icmpv6_send);
 473
 474 static void icmpv6_echo_reply(struct sk_buff *skb)
 475 {
 476         struct sock *sk;
 477         struct inet6_dev *idev;
 478         struct ipv6_pinfo *np;
 479         struct in6_addr *saddr = NULL;
 480         struct icmp6hdr *icmph = icmp6_hdr(skb);
 481         struct icmp6hdr tmp_hdr;
 482         struct flowi fl;
 483         struct icmpv6_msg msg;
 484         struct dst_entry *dst;
 485         int err = 0;
 486         int hlimit;
 487         int tclass;
 488
 489         saddr = &ipv6_hdr(skb)->daddr;
 490
 491         if (!ipv6_unicast_destination(skb))
 492                 saddr = NULL;
 493
 494         memcpy(&tmp_hdr, icmph, sizeof(tmp_hdr));
 495         tmp_hdr.icmp6_type = ICMPV6_ECHO_REPLY;
 496
 497         memset(&fl, 0, sizeof(fl));
 498         fl.proto = IPPROTO_ICMPV6;
 499         ipv6_addr_copy(&fl.fl6_dst, &ipv6_hdr(skb)->saddr);
 500         if (saddr)
 501                 ipv6_addr_copy(&fl.fl6_src, saddr);
 502         fl.oif = skb->dev->ifindex;
 503         fl.fl_icmp_type = ICMPV6_ECHO_REPLY;
 504         security_skb_classify_flow(skb, &fl);
 505
 506         if (icmpv6_xmit_lock())
 507                 return;
 508
 509         sk = icmpv6_socket->sk;
 510         np = inet6_sk(sk);
 511
 512         if (!fl.oif && ipv6_addr_is_multicast(&fl.fl6_dst))
 513                 fl.oif = np->mcast_oif;
 514
 515         err = ip6_dst_lookup(sk, &dst, &fl);
 516         if (err)
 517                 goto out;
 518         if ((err = xfrm_lookup(&dst, &fl, sk, 0)) < 0)
 519                 goto out;
 520
 521         if (ipv6_addr_is_multicast(&fl.fl6_dst))
 522                 hlimit = np->mcast_hops;
 523         else
 524                 hlimit = np->hop_limit;
 525         if (hlimit < 0)
 526                 hlimit = dst_metric(dst, RTAX_HOPLIMIT);
 527         if (hlimit < 0)
 528                 hlimit = ipv6_get_hoplimit(dst->dev);
 529
 530         tclass = np->tclass;
 531         if (tclass < 0)
 532                 tclass = 0;
 533
 534         idev = in6_dev_get(skb->dev);
 535
 536         msg.skb = skb;
 537         msg.offset = 0;
 538         msg.type = ICMPV6_ECHO_REPLY;
 539
 540         err = ip6_append_data(sk, icmpv6_getfrag, &msg, skb->len + sizeof(struct icmp6hdr),
 541                                 sizeof(struct icmp6hdr), hlimit, tclass, NULL, &fl,
 542                                 (struct rt6_info*)dst, MSG_DONTWAIT);
 543
 544         if (err) {
 545                 ip6_flush_pending_frames(sk);
 546                 goto out_put;
 547         }
 548         err = icmpv6_push_pending_frames(sk, &fl, &tmp_hdr, skb->len + sizeof(struct icmp6hdr));
 549
 550 out_put:
 551         if (likely(idev != NULL))
 552                 in6_dev_put(idev);
 553         dst_release(dst);
 554 out:
 555         icmpv6_xmit_unlock();
 556 }
 557
 558 static void icmpv6_notify(struct sk_buff *skb, int type, int code, __be32 info)
 559 {
 560         struct in6_addr *saddr, *daddr;
 561         struct inet6_protocol *ipprot;
 562         struct sock *sk;
 563         int inner_offset;
 564         int hash;
 565         u8 nexthdr;
 566
 567         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
 568                 return;
 569
 570         nexthdr = ((struct ipv6hdr *)skb->data)->nexthdr;
 571         if (ipv6_ext_hdr(nexthdr)) {
 572                 /* now skip over extension headers */
 573                 inner_offset = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &nexthdr);
 574                 if (inner_offset<0)
 575                         return;
 576         } else {
 577                 inner_offset = sizeof(struct ipv6hdr);
 578         }
 579
 580         /* Checkin header including 8 bytes of inner protocol header. */
 581         if (!pskb_may_pull(skb, inner_offset+8))
 582                 return;
 583
 584         saddr = &ipv6_hdr(skb)->saddr;
 585         daddr = &ipv6_hdr(skb)->daddr;
 586
 587         /* BUGGG_FUTURE: we should try to parse exthdrs in this packet.
 588            Without this we will not able f.e. to make source routed
 589            pmtu discovery.
 590            Corresponding argument (opt) to notifiers is already added.
 591            --ANK (980726)
 592          */
 593
 594         hash = nexthdr & (MAX_INET_PROTOS - 1);
 595
 596         rcu_read_lock();
 597         ipprot = rcu_dereference(inet6_protos[hash]);
 598         if (ipprot && ipprot->err_handler)
 599                 ipprot->err_handler(skb, NULL, type, code, inner_offset, info);
 600         rcu_read_unlock();
 601
 602         read_lock(&raw_v6_lock);
 603         if ((sk = sk_head(&raw_v6_htable[hash])) != NULL) {
 604                 while ((sk = __raw_v6_lookup(sk, nexthdr, saddr, daddr,
 605                                             IP6CB(skb)->iif))) {
 606                         rawv6_err(sk, skb, NULL, type, code, inner_offset, info);
 607                         sk = sk_next(sk);
 608                 }
 609         }
 610         read_unlock(&raw_v6_lock);
 611 }
 612
 613 /*
 614  *      Handle icmp messages
 615  */
 616
 617 static int icmpv6_rcv(struct sk_buff **pskb)
 618 {
 619         struct sk_buff *skb = *pskb;
 620         struct net_device *dev = skb->dev;
 621         struct inet6_dev *idev = __in6_dev_get(dev);
 622         struct in6_addr *saddr, *daddr;
 623         struct ipv6hdr *orig_hdr;
 624         struct icmp6hdr *hdr;
 625         int type;
 626
 627         ICMP6_INC_STATS_BH(idev, ICMP6_MIB_INMSGS);
 628
 629         saddr = &ipv6_hdr(skb)->saddr;
 630         daddr = &ipv6_hdr(skb)->daddr;
 631
 632         /* Perform checksum. */
 633         switch (skb->ip_summed) {
 634         case CHECKSUM_COMPLETE:
 635                 if (!csum_ipv6_magic(saddr, daddr, skb->len, IPPROTO_ICMPV6,
 636                                      skb->csum))
 637                         break;
 638                 /* fall through */
 639         case CHECKSUM_NONE:
 640                 skb->csum = ~csum_unfold(csum_ipv6_magic(saddr, daddr, skb->len,
 641                                              IPPROTO_ICMPV6, 0));
 642                 if (__skb_checksum_complete(skb)) {
 643                         LIMIT_NETDEBUG(KERN_DEBUG "ICMPv6 checksum failed [" NIP6_FMT " > " NIP6_FMT "]\n",
 644                                        NIP6(*saddr), NIP6(*daddr));
 645                         goto discard_it;
 646                 }
 647         }
 648
 649         if (!pskb_pull(skb, sizeof(struct icmp6hdr)))
 650                 goto discard_it;
 651
 652         hdr = icmp6_hdr(skb);
 653
 654         type = hdr->icmp6_type;
 655
 656         ICMP6MSGIN_INC_STATS_BH(idev, type);
 657
 658         switch (type) {
 659         case ICMPV6_ECHO_REQUEST:
 660                 icmpv6_echo_reply(skb);
 661                 break;
 662
 663         case ICMPV6_ECHO_REPLY:
 664                 /* we couldn't care less */
 665                 break;
 666
 667         case ICMPV6_PKT_TOOBIG:
 668                 /* BUGGG_FUTURE: if packet contains rthdr, we cannot update
 669                    standard destination cache. Seems, only "advanced"
 670                    destination cache will allow to solve this problem
 671                    --ANK (980726)
 672                  */
 673                 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
 674                         goto discard_it;
 675                 hdr = icmp6_hdr(skb);
 676                 orig_hdr = (struct ipv6hdr *) (hdr + 1);
 677                 rt6_pmtu_discovery(&orig_hdr->daddr, &orig_hdr->saddr, dev,
 678                                    ntohl(hdr->icmp6_mtu));
 679
 680                 /*
 681                  *      Drop through to notify
 682                  */
 683
 684         case ICMPV6_DEST_UNREACH:
 685         case ICMPV6_TIME_EXCEED:
 686         case ICMPV6_PARAMPROB:
 687                 icmpv6_notify(skb, type, hdr->icmp6_code, hdr->icmp6_mtu);
 688                 break;
 689
 690         case NDISC_ROUTER_SOLICITATION:
 691         case NDISC_ROUTER_ADVERTISEMENT:
 692         case NDISC_NEIGHBOUR_SOLICITATION:
 693         case NDISC_NEIGHBOUR_ADVERTISEMENT:
 694         case NDISC_REDIRECT:
 695                 ndisc_rcv(skb);
 696                 break;
 697
 698         case ICMPV6_MGM_QUERY:
 699                 igmp6_event_query(skb);
 700                 break;
 701
 702         case ICMPV6_MGM_REPORT:
 703                 igmp6_event_report(skb);
 704                 break;
 705
 706         case ICMPV6_MGM_REDUCTION:
 707         case ICMPV6_NI_QUERY:
 708         case ICMPV6_NI_REPLY:
 709         case ICMPV6_MLD2_REPORT:
 710         case ICMPV6_DHAAD_REQUEST:
 711         case ICMPV6_DHAAD_REPLY:
 712         case ICMPV6_MOBILE_PREFIX_SOL:
 713         case ICMPV6_MOBILE_PREFIX_ADV:
 714                 break;
 715
 716         default:
 717                 LIMIT_NETDEBUG(KERN_DEBUG "icmpv6: msg of unknown type\n");
 718
 719                 /* informational */
 720                 if (type & ICMPV6_INFOMSG_MASK)
 721                         break;
 722
 723                 /*
 724                  * error of unknown type.
 725                  * must pass to upper level
 726                  */
 727
 728                 icmpv6_notify(skb, type, hdr->icmp6_code, hdr->icmp6_mtu);
 729         }
 730
 731         kfree_skb(skb);
 732         return 0;
 733
 734 discard_it:
 735         ICMP6_INC_STATS_BH(idev, ICMP6_MIB_INERRORS);
 736         kfree_skb(skb);
 737         return 0;
 738 }
 739
 740 /*
 741  * Special lock-class for __icmpv6_socket:
 742  */
 743 static struct lock_class_key icmpv6_socket_sk_dst_lock_key;
 744
 745 int __init icmpv6_init(struct net_proto_family *ops)
 746 {
 747         struct sock *sk;
 748         int err, i, j;
 749
 750         for_each_possible_cpu(i) {
 751                 err = sock_create_kern(PF_INET6, SOCK_RAW, IPPROTO_ICMPV6,
 752                                        &per_cpu(__icmpv6_socket, i));
 753                 if (err < 0) {
 754                         printk(KERN_ERR
 755                                "Failed to initialize the ICMP6 control socket "
 756                                "(err %d).\n",
 757                                err);
 758                         goto fail;
 759                 }
 760
 761                 sk = per_cpu(__icmpv6_socket, i)->sk;
 762                 sk->sk_allocation = GFP_ATOMIC;
 763                 /*
 764                  * Split off their lock-class, because sk->sk_dst_lock
 765                  * gets used from softirqs, which is safe for
 766                  * __icmpv6_socket (because those never get directly used
 767                  * via userspace syscalls), but unsafe for normal sockets.
 768                  */
 769                 lockdep_set_class(&sk->sk_dst_lock,
 770                                   &icmpv6_socket_sk_dst_lock_key);
 771
 772                 /* Enough space for 2 64K ICMP packets, including
 773                  * sk_buff struct overhead.
 774                  */
 775                 sk->sk_sndbuf =
 776                         (2 * ((64 * 1024) + sizeof(struct sk_buff)));
 777
 778                 sk->sk_prot->unhash(sk);
 779         }
 780
 781
 782         if (inet6_add_protocol(&icmpv6_protocol, IPPROTO_ICMPV6) < 0) {
 783                 printk(KERN_ERR "Failed to register ICMP6 protocol\n");
 784                 err = -EAGAIN;
 785                 goto fail;
 786         }
 787
 788         return 0;
 789
 790  fail:
 791         for (j = 0; j < i; j++) {
 792                 if (!cpu_possible(j))
 793                         continue;
 794                 sock_release(per_cpu(__icmpv6_socket, j));
 795         }
 796
 797         return err;
 798 }
 799
 800 void icmpv6_cleanup(void)
 801 {
 802         int i;
 803
 804         for_each_possible_cpu(i) {
 805                 sock_release(per_cpu(__icmpv6_socket, i));
 806         }
 807         inet6_del_protocol(&icmpv6_protocol, IPPROTO_ICMPV6);
 808 }
 809
 810 static const struct icmp6_err {
 811         int err;
 812         int fatal;
 813 } tab_unreach[] = {
 814         {       /* NOROUTE */
 815                 .err    = ENETUNREACH,
 816                 .fatal  = 0,
 817         },
 818         {       /* ADM_PROHIBITED */
 819                 .err    = EACCES,
 820                 .fatal  = 1,
 821         },
 822         {       /* Was NOT_NEIGHBOUR, now reserved */
 823                 .err    = EHOSTUNREACH,
 824                 .fatal  = 0,
 825         },
 826         {       /* ADDR_UNREACH */
 827                 .err    = EHOSTUNREACH,
 828                 .fatal  = 0,
 829         },
 830         {       /* PORT_UNREACH */
 831                 .err    = ECONNREFUSED,
 832                 .fatal  = 1,
 833         },
 834 };
 835
 836 int icmpv6_err_convert(int type, int code, int *err)
 837 {
 838         int fatal = 0;
 839
 840         *err = EPROTO;
 841
 842         switch (type) {
 843         case ICMPV6_DEST_UNREACH:
 844                 fatal = 1;
 845                 if (code <= ICMPV6_PORT_UNREACH) {
 846                         *err  = tab_unreach[code].err;
 847                         fatal = tab_unreach[code].fatal;
 848                 }
 849                 break;
 850
 851         case ICMPV6_PKT_TOOBIG:
 852                 *err = EMSGSIZE;
 853                 break;
 854
 855         case ICMPV6_PARAMPROB:
 856                 *err = EPROTO;
 857                 fatal = 1;
 858                 break;
 859
 860         case ICMPV6_TIME_EXCEED:
 861                 *err = EHOSTUNREACH;
 862                 break;
 863         }
 864
 865         return fatal;
 866 }
 867
 868 EXPORT_SYMBOL(icmpv6_err_convert);
 869
 870 #ifdef CONFIG_SYSCTL
 871 ctl_table ipv6_icmp_table[] = {
 872         {
 873                 .ctl_name       = NET_IPV6_ICMP_RATELIMIT,
 874                 .procname       = "ratelimit",
 875                 .data           = &sysctl_icmpv6_time,
 876                 .maxlen         = sizeof(int),
 877                 .mode           = 0644,
 878                 .proc_handler   = &proc_dointvec
 879         },
 880         { .ctl_name = 0 },
 881 };
 882 #endif
 883