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 #include <net/xfrm.h>
  67
  68 #include <asm/uaccess.h>
  69 #include <asm/system.h>
  70
  71 DEFINE_SNMP_STAT(struct icmpv6_mib, icmpv6_statistics) __read_mostly;
  72 EXPORT_SYMBOL(icmpv6_statistics);
  73 DEFINE_SNMP_STAT(struct icmpv6msg_mib, icmpv6msg_statistics) __read_mostly;
  74 EXPORT_SYMBOL(icmpv6msg_statistics);
  75
  76 /*
  77  *      The ICMP socket(s). This is the most convenient way to flow control
  78  *      our ICMP output as well as maintain a clean interface throughout
  79  *      all layers. All Socketless IP sends will soon be gone.
  80  *
  81  *      On SMP we have one ICMP socket per-cpu.
  82  */
  83 static DEFINE_PER_CPU(struct socket *, __icmpv6_socket) = NULL;
  84 #define icmpv6_socket   __get_cpu_var(__icmpv6_socket)
  85
  86 static int icmpv6_rcv(struct sk_buff *skb);
  87
  88 static struct inet6_protocol icmpv6_protocol = {
  89         .handler        =       icmpv6_rcv,
  90         .flags          =       INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
  91 };
  92
  93 static __inline__ int icmpv6_xmit_lock(void)
  94 {
  95         local_bh_disable();
  96
  97         if (unlikely(!spin_trylock(&icmpv6_socket->sk->sk_lock.slock))) {
  98                 /* This can happen if the output path (f.e. SIT or
  99                  * ip6ip6 tunnel) signals dst_link_failure() for an
 100                  * outgoing ICMP6 packet.
 101                  */
 102                 local_bh_enable();
 103                 return 1;
 104         }
 105         return 0;
 106 }
 107
 108 static __inline__ void icmpv6_xmit_unlock(void)
 109 {
 110         spin_unlock_bh(&icmpv6_socket->sk->sk_lock.slock);
 111 }
 112
 113 /*
 114  * Slightly more convenient version of icmpv6_send.
 115  */
 116 void icmpv6_param_prob(struct sk_buff *skb, int code, int pos)
 117 {
 118         icmpv6_send(skb, ICMPV6_PARAMPROB, code, pos, skb->dev);
 119         kfree_skb(skb);
 120 }
 121
 122 /*
 123  * Figure out, may we reply to this packet with icmp error.
 124  *
 125  * We do not reply, if:
 126  *      - it was icmp error message.
 127  *      - it is truncated, so that it is known, that protocol is ICMPV6
 128  *        (i.e. in the middle of some exthdr)
 129  *
 130  *      --ANK (980726)
 131  */
 132
 133 static int is_ineligible(struct sk_buff *skb)
 134 {
 135         int ptr = (u8 *)(ipv6_hdr(skb) + 1) - skb->data;
 136         int len = skb->len - ptr;
 137         __u8 nexthdr = ipv6_hdr(skb)->nexthdr;
 138
 139         if (len < 0)
 140                 return 1;
 141
 142         ptr = ipv6_skip_exthdr(skb, ptr, &nexthdr);
 143         if (ptr < 0)
 144                 return 0;
 145         if (nexthdr == IPPROTO_ICMPV6) {
 146                 u8 _type, *tp;
 147                 tp = skb_header_pointer(skb,
 148                         ptr+offsetof(struct icmp6hdr, icmp6_type),
 149                         sizeof(_type), &_type);
 150                 if (tp == NULL ||
 151                     !(*tp & ICMPV6_INFOMSG_MASK))
 152                         return 1;
 153         }
 154         return 0;
 155 }
 156
 157 /*
 158  * Check the ICMP output rate limit
 159  */
 160 static inline int icmpv6_xrlim_allow(struct sock *sk, int type,
 161                                      struct flowi *fl)
 162 {
 163         struct dst_entry *dst;
 164         int res = 0;
 165
 166         /* Informational messages are not limited. */
 167         if (type & ICMPV6_INFOMSG_MASK)
 168                 return 1;
 169
 170         /* Do not limit pmtu discovery, it would break it. */
 171         if (type == ICMPV6_PKT_TOOBIG)
 172                 return 1;
 173
 174         /*
 175          * Look up the output route.
 176          * XXX: perhaps the expire for routing entries cloned by
 177          * this lookup should be more aggressive (not longer than timeout).
 178          */
 179         dst = ip6_route_output(sk, fl);
 180         if (dst->error) {
 181                 IP6_INC_STATS(ip6_dst_idev(dst),
 182                               IPSTATS_MIB_OUTNOROUTES);
 183         } else if (dst->dev && (dst->dev->flags&IFF_LOOPBACK)) {
 184                 res = 1;
 185         } else {
 186                 struct rt6_info *rt = (struct rt6_info *)dst;
 187                 int tmo = init_net.ipv6.sysctl.icmpv6_time;
 188
 189                 /* Give more bandwidth to wider prefixes. */
 190                 if (rt->rt6i_dst.plen < 128)
 191                         tmo >>= ((128 - rt->rt6i_dst.plen)>>5);
 192
 193                 res = xrlim_allow(dst, tmo);
 194         }
 195         dst_release(dst);
 196         return res;
 197 }
 198
 199 /*
 200  *      an inline helper for the "simple" if statement below
 201  *      checks if parameter problem report is caused by an
 202  *      unrecognized IPv6 option that has the Option Type
 203  *      highest-order two bits set to 10
 204  */
 205
 206 static __inline__ int opt_unrec(struct sk_buff *skb, __u32 offset)
 207 {
 208         u8 _optval, *op;
 209
 210         offset += skb_network_offset(skb);
 211         op = skb_header_pointer(skb, offset, sizeof(_optval), &_optval);
 212         if (op == NULL)
 213                 return 1;
 214         return (*op & 0xC0) == 0x80;
 215 }
 216
 217 static int icmpv6_push_pending_frames(struct sock *sk, struct flowi *fl, struct icmp6hdr *thdr, int len)
 218 {
 219         struct sk_buff *skb;
 220         struct icmp6hdr *icmp6h;
 221         int err = 0;
 222
 223         if ((skb = skb_peek(&sk->sk_write_queue)) == NULL)
 224                 goto out;
 225
 226         icmp6h = icmp6_hdr(skb);
 227         memcpy(icmp6h, thdr, sizeof(struct icmp6hdr));
 228         icmp6h->icmp6_cksum = 0;
 229
 230         if (skb_queue_len(&sk->sk_write_queue) == 1) {
 231                 skb->csum = csum_partial((char *)icmp6h,
 232                                         sizeof(struct icmp6hdr), skb->csum);
 233                 icmp6h->icmp6_cksum = csum_ipv6_magic(&fl->fl6_src,
 234                                                       &fl->fl6_dst,
 235                                                       len, fl->proto,
 236                                                       skb->csum);
 237         } else {
 238                 __wsum tmp_csum = 0;
 239
 240                 skb_queue_walk(&sk->sk_write_queue, skb) {
 241                         tmp_csum = csum_add(tmp_csum, skb->csum);
 242                 }
 243
 244                 tmp_csum = csum_partial((char *)icmp6h,
 245                                         sizeof(struct icmp6hdr), tmp_csum);
 246                 icmp6h->icmp6_cksum = csum_ipv6_magic(&fl->fl6_src,
 247                                                       &fl->fl6_dst,
 248                                                       len, fl->proto,
 249                                                       tmp_csum);
 250         }
 251         ip6_push_pending_frames(sk);
 252 out:
 253         return err;
 254 }
 255
 256 struct icmpv6_msg {
 257         struct sk_buff  *skb;
 258         int             offset;
 259         uint8_t         type;
 260 };
 261
 262 static int icmpv6_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb)
 263 {
 264         struct icmpv6_msg *msg = (struct icmpv6_msg *) from;
 265         struct sk_buff *org_skb = msg->skb;
 266         __wsum csum = 0;
 267
 268         csum = skb_copy_and_csum_bits(org_skb, msg->offset + offset,
 269                                       to, len, csum);
 270         skb->csum = csum_block_add(skb->csum, csum, odd);
 271         if (!(msg->type & ICMPV6_INFOMSG_MASK))
 272                 nf_ct_attach(skb, org_skb);
 273         return 0;
 274 }
 275
 276 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
 277 static void mip6_addr_swap(struct sk_buff *skb)
 278 {
 279         struct ipv6hdr *iph = ipv6_hdr(skb);
 280         struct inet6_skb_parm *opt = IP6CB(skb);
 281         struct ipv6_destopt_hao *hao;
 282         struct in6_addr tmp;
 283         int off;
 284
 285         if (opt->dsthao) {
 286                 off = ipv6_find_tlv(skb, opt->dsthao, IPV6_TLV_HAO);
 287                 if (likely(off >= 0)) {
 288                         hao = (struct ipv6_destopt_hao *)
 289                                         (skb_network_header(skb) + off);
 290                         ipv6_addr_copy(&tmp, &iph->saddr);
 291                         ipv6_addr_copy(&iph->saddr, &hao->addr);
 292                         ipv6_addr_copy(&hao->addr, &tmp);
 293                 }
 294         }
 295 }
 296 #else
 297 static inline void mip6_addr_swap(struct sk_buff *skb) {}
 298 #endif
 299
 300 /*
 301  *      Send an ICMP message in response to a packet in error
 302  */
 303 void icmpv6_send(struct sk_buff *skb, int type, int code, __u32 info,
 304                  struct net_device *dev)
 305 {
 306         struct inet6_dev *idev = NULL;
 307         struct ipv6hdr *hdr = ipv6_hdr(skb);
 308         struct sock *sk;
 309         struct ipv6_pinfo *np;
 310         struct in6_addr *saddr = NULL;
 311         struct dst_entry *dst;
 312         struct dst_entry *dst2;
 313         struct icmp6hdr tmp_hdr;
 314         struct flowi fl;
 315         struct flowi fl2;
 316         struct icmpv6_msg msg;
 317         int iif = 0;
 318         int addr_type = 0;
 319         int len;
 320         int hlimit, tclass;
 321         int err = 0;
 322
 323         if ((u8 *)hdr < skb->head ||
 324             (skb->network_header + sizeof(*hdr)) > skb->tail)
 325                 return;
 326
 327         /*
 328          *      Make sure we respect the rules
 329          *      i.e. RFC 1885 2.4(e)
 330          *      Rule (e.1) is enforced by not using icmpv6_send
 331          *      in any code that processes icmp errors.
 332          */
 333         addr_type = ipv6_addr_type(&hdr->daddr);
 334
 335         if (ipv6_chk_addr(&init_net, &hdr->daddr, skb->dev, 0))
 336                 saddr = &hdr->daddr;
 337
 338         /*
 339          *      Dest addr check
 340          */
 341
 342         if ((addr_type & IPV6_ADDR_MULTICAST || skb->pkt_type != PACKET_HOST)) {
 343                 if (type != ICMPV6_PKT_TOOBIG &&
 344                     !(type == ICMPV6_PARAMPROB &&
 345                       code == ICMPV6_UNK_OPTION &&
 346                       (opt_unrec(skb, info))))
 347                         return;
 348
 349                 saddr = NULL;
 350         }
 351
 352         addr_type = ipv6_addr_type(&hdr->saddr);
 353
 354         /*
 355          *      Source addr check
 356          */
 357
 358         if (addr_type & IPV6_ADDR_LINKLOCAL)
 359                 iif = skb->dev->ifindex;
 360
 361         /*
 362          *      Must not send error if the source does not uniquely
 363          *      identify a single node (RFC2463 Section 2.4).
 364          *      We check unspecified / multicast addresses here,
 365          *      and anycast addresses will be checked later.
 366          */
 367         if ((addr_type == IPV6_ADDR_ANY) || (addr_type & IPV6_ADDR_MULTICAST)) {
 368                 LIMIT_NETDEBUG(KERN_DEBUG "icmpv6_send: addr_any/mcast source\n");
 369                 return;
 370         }
 371
 372         /*
 373          *      Never answer to a ICMP packet.
 374          */
 375         if (is_ineligible(skb)) {
 376                 LIMIT_NETDEBUG(KERN_DEBUG "icmpv6_send: no reply to icmp error\n");
 377                 return;
 378         }
 379
 380         mip6_addr_swap(skb);
 381
 382         memset(&fl, 0, sizeof(fl));
 383         fl.proto = IPPROTO_ICMPV6;
 384         ipv6_addr_copy(&fl.fl6_dst, &hdr->saddr);
 385         if (saddr)
 386                 ipv6_addr_copy(&fl.fl6_src, saddr);
 387         fl.oif = iif;
 388         fl.fl_icmp_type = type;
 389         fl.fl_icmp_code = code;
 390         security_skb_classify_flow(skb, &fl);
 391
 392         if (icmpv6_xmit_lock())
 393                 return;
 394
 395         sk = icmpv6_socket->sk;
 396         np = inet6_sk(sk);
 397
 398         if (!icmpv6_xrlim_allow(sk, type, &fl))
 399                 goto out;
 400
 401         tmp_hdr.icmp6_type = type;
 402         tmp_hdr.icmp6_code = code;
 403         tmp_hdr.icmp6_cksum = 0;
 404         tmp_hdr.icmp6_pointer = htonl(info);
 405
 406         if (!fl.oif && ipv6_addr_is_multicast(&fl.fl6_dst))
 407                 fl.oif = np->mcast_oif;
 408
 409         err = ip6_dst_lookup(sk, &dst, &fl);
 410         if (err)
 411                 goto out;
 412
 413         /*
 414          * We won't send icmp if the destination is known
 415          * anycast.
 416          */
 417         if (((struct rt6_info *)dst)->rt6i_flags & RTF_ANYCAST) {
 418                 LIMIT_NETDEBUG(KERN_DEBUG "icmpv6_send: acast source\n");
 419                 goto out_dst_release;
 420         }
 421
 422         /* No need to clone since we're just using its address. */
 423         dst2 = dst;
 424
 425         err = xfrm_lookup(&dst, &fl, sk, 0);
 426         switch (err) {
 427         case 0:
 428                 if (dst != dst2)
 429                         goto route_done;
 430                 break;
 431         case -EPERM:
 432                 dst = NULL;
 433                 break;
 434         default:
 435                 goto out;
 436         }
 437
 438         if (xfrm_decode_session_reverse(skb, &fl2, AF_INET6))
 439                 goto out;
 440
 441         if (ip6_dst_lookup(sk, &dst2, &fl))
 442                 goto out;
 443
 444         err = xfrm_lookup(&dst2, &fl, sk, XFRM_LOOKUP_ICMP);
 445         if (err == -ENOENT) {
 446                 if (!dst)
 447                         goto out;
 448                 goto route_done;
 449         }
 450
 451         dst_release(dst);
 452         dst = dst2;
 453
 454         if (err)
 455                 goto out;
 456
 457 route_done:
 458         if (ipv6_addr_is_multicast(&fl.fl6_dst))
 459                 hlimit = np->mcast_hops;
 460         else
 461                 hlimit = np->hop_limit;
 462         if (hlimit < 0)
 463                 hlimit = dst_metric(dst, RTAX_HOPLIMIT);
 464         if (hlimit < 0)
 465                 hlimit = ipv6_get_hoplimit(dst->dev);
 466
 467         tclass = np->tclass;
 468         if (tclass < 0)
 469                 tclass = 0;
 470
 471         msg.skb = skb;
 472         msg.offset = skb_network_offset(skb);
 473         msg.type = type;
 474
 475         len = skb->len - msg.offset;
 476         len = min_t(unsigned int, len, IPV6_MIN_MTU - sizeof(struct ipv6hdr) -sizeof(struct icmp6hdr));
 477         if (len < 0) {
 478                 LIMIT_NETDEBUG(KERN_DEBUG "icmp: len problem\n");
 479                 goto out_dst_release;
 480         }
 481
 482         idev = in6_dev_get(skb->dev);
 483
 484         err = ip6_append_data(sk, icmpv6_getfrag, &msg,
 485                               len + sizeof(struct icmp6hdr),
 486                               sizeof(struct icmp6hdr),
 487                               hlimit, tclass, NULL, &fl, (struct rt6_info*)dst,
 488                               MSG_DONTWAIT);
 489         if (err) {
 490                 ip6_flush_pending_frames(sk);
 491                 goto out_put;
 492         }
 493         err = icmpv6_push_pending_frames(sk, &fl, &tmp_hdr, len + sizeof(struct icmp6hdr));
 494
 495 out_put:
 496         if (likely(idev != NULL))
 497                 in6_dev_put(idev);
 498 out_dst_release:
 499         dst_release(dst);
 500 out:
 501         icmpv6_xmit_unlock();
 502 }
 503
 504 EXPORT_SYMBOL(icmpv6_send);
 505
 506 static void icmpv6_echo_reply(struct sk_buff *skb)
 507 {
 508         struct sock *sk;
 509         struct inet6_dev *idev;
 510         struct ipv6_pinfo *np;
 511         struct in6_addr *saddr = NULL;
 512         struct icmp6hdr *icmph = icmp6_hdr(skb);
 513         struct icmp6hdr tmp_hdr;
 514         struct flowi fl;
 515         struct icmpv6_msg msg;
 516         struct dst_entry *dst;
 517         int err = 0;
 518         int hlimit;
 519         int tclass;
 520
 521         saddr = &ipv6_hdr(skb)->daddr;
 522
 523         if (!ipv6_unicast_destination(skb))
 524                 saddr = NULL;
 525
 526         memcpy(&tmp_hdr, icmph, sizeof(tmp_hdr));
 527         tmp_hdr.icmp6_type = ICMPV6_ECHO_REPLY;
 528
 529         memset(&fl, 0, sizeof(fl));
 530         fl.proto = IPPROTO_ICMPV6;
 531         ipv6_addr_copy(&fl.fl6_dst, &ipv6_hdr(skb)->saddr);
 532         if (saddr)
 533                 ipv6_addr_copy(&fl.fl6_src, saddr);
 534         fl.oif = skb->dev->ifindex;
 535         fl.fl_icmp_type = ICMPV6_ECHO_REPLY;
 536         security_skb_classify_flow(skb, &fl);
 537
 538         if (icmpv6_xmit_lock())
 539                 return;
 540
 541         sk = icmpv6_socket->sk;
 542         np = inet6_sk(sk);
 543
 544         if (!fl.oif && ipv6_addr_is_multicast(&fl.fl6_dst))
 545                 fl.oif = np->mcast_oif;
 546
 547         err = ip6_dst_lookup(sk, &dst, &fl);
 548         if (err)
 549                 goto out;
 550         if ((err = xfrm_lookup(&dst, &fl, sk, 0)) < 0)
 551                 goto out;
 552
 553         if (ipv6_addr_is_multicast(&fl.fl6_dst))
 554                 hlimit = np->mcast_hops;
 555         else
 556                 hlimit = np->hop_limit;
 557         if (hlimit < 0)
 558                 hlimit = dst_metric(dst, RTAX_HOPLIMIT);
 559         if (hlimit < 0)
 560                 hlimit = ipv6_get_hoplimit(dst->dev);
 561
 562         tclass = np->tclass;
 563         if (tclass < 0)
 564                 tclass = 0;
 565
 566         idev = in6_dev_get(skb->dev);
 567
 568         msg.skb = skb;
 569         msg.offset = 0;
 570         msg.type = ICMPV6_ECHO_REPLY;
 571
 572         err = ip6_append_data(sk, icmpv6_getfrag, &msg, skb->len + sizeof(struct icmp6hdr),
 573                                 sizeof(struct icmp6hdr), hlimit, tclass, NULL, &fl,
 574                                 (struct rt6_info*)dst, MSG_DONTWAIT);
 575
 576         if (err) {
 577                 ip6_flush_pending_frames(sk);
 578                 goto out_put;
 579         }
 580         err = icmpv6_push_pending_frames(sk, &fl, &tmp_hdr, skb->len + sizeof(struct icmp6hdr));
 581
 582 out_put:
 583         if (likely(idev != NULL))
 584                 in6_dev_put(idev);
 585         dst_release(dst);
 586 out:
 587         icmpv6_xmit_unlock();
 588 }
 589
 590 static void icmpv6_notify(struct sk_buff *skb, int type, int code, __be32 info)
 591 {
 592         struct inet6_protocol *ipprot;
 593         int inner_offset;
 594         int hash;
 595         u8 nexthdr;
 596
 597         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
 598                 return;
 599
 600         nexthdr = ((struct ipv6hdr *)skb->data)->nexthdr;
 601         if (ipv6_ext_hdr(nexthdr)) {
 602                 /* now skip over extension headers */
 603                 inner_offset = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &nexthdr);
 604                 if (inner_offset<0)
 605                         return;
 606         } else {
 607                 inner_offset = sizeof(struct ipv6hdr);
 608         }
 609
 610         /* Checkin header including 8 bytes of inner protocol header. */
 611         if (!pskb_may_pull(skb, inner_offset+8))
 612                 return;
 613
 614         /* BUGGG_FUTURE: we should try to parse exthdrs in this packet.
 615            Without this we will not able f.e. to make source routed
 616            pmtu discovery.
 617            Corresponding argument (opt) to notifiers is already added.
 618            --ANK (980726)
 619          */
 620
 621         hash = nexthdr & (MAX_INET_PROTOS - 1);
 622
 623         rcu_read_lock();
 624         ipprot = rcu_dereference(inet6_protos[hash]);
 625         if (ipprot && ipprot->err_handler)
 626                 ipprot->err_handler(skb, NULL, type, code, inner_offset, info);
 627         rcu_read_unlock();
 628
 629         raw6_icmp_error(skb, nexthdr, type, code, inner_offset, info);
 630 }
 631
 632 /*
 633  *      Handle icmp messages
 634  */
 635
 636 static int icmpv6_rcv(struct sk_buff *skb)
 637 {
 638         struct net_device *dev = skb->dev;
 639         struct inet6_dev *idev = __in6_dev_get(dev);
 640         struct in6_addr *saddr, *daddr;
 641         struct ipv6hdr *orig_hdr;
 642         struct icmp6hdr *hdr;
 643         int type;
 644
 645         if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
 646                 int nh;
 647
 648                 if (!(skb->sp && skb->sp->xvec[skb->sp->len - 1]->props.flags &
 649                                  XFRM_STATE_ICMP))
 650                         goto drop_no_count;
 651
 652                 if (!pskb_may_pull(skb, sizeof(*hdr) + sizeof(*orig_hdr)))
 653                         goto drop_no_count;
 654
 655                 nh = skb_network_offset(skb);
 656                 skb_set_network_header(skb, sizeof(*hdr));
 657
 658                 if (!xfrm6_policy_check_reverse(NULL, XFRM_POLICY_IN, skb))
 659                         goto drop_no_count;
 660
 661                 skb_set_network_header(skb, nh);
 662         }
 663
 664         ICMP6_INC_STATS_BH(idev, ICMP6_MIB_INMSGS);
 665
 666         saddr = &ipv6_hdr(skb)->saddr;
 667         daddr = &ipv6_hdr(skb)->daddr;
 668
 669         /* Perform checksum. */
 670         switch (skb->ip_summed) {
 671         case CHECKSUM_COMPLETE:
 672                 if (!csum_ipv6_magic(saddr, daddr, skb->len, IPPROTO_ICMPV6,
 673                                      skb->csum))
 674                         break;
 675                 /* fall through */
 676         case CHECKSUM_NONE:
 677                 skb->csum = ~csum_unfold(csum_ipv6_magic(saddr, daddr, skb->len,
 678                                              IPPROTO_ICMPV6, 0));
 679                 if (__skb_checksum_complete(skb)) {
 680                         LIMIT_NETDEBUG(KERN_DEBUG "ICMPv6 checksum failed [" NIP6_FMT " > " NIP6_FMT "]\n",
 681                                        NIP6(*saddr), NIP6(*daddr));
 682                         goto discard_it;
 683                 }
 684         }
 685
 686         __skb_pull(skb, sizeof(*hdr));
 687
 688         hdr = icmp6_hdr(skb);
 689
 690         type = hdr->icmp6_type;
 691
 692         ICMP6MSGIN_INC_STATS_BH(idev, type);
 693
 694         switch (type) {
 695         case ICMPV6_ECHO_REQUEST:
 696                 icmpv6_echo_reply(skb);
 697                 break;
 698
 699         case ICMPV6_ECHO_REPLY:
 700                 /* we couldn't care less */
 701                 break;
 702
 703         case ICMPV6_PKT_TOOBIG:
 704                 /* BUGGG_FUTURE: if packet contains rthdr, we cannot update
 705                    standard destination cache. Seems, only "advanced"
 706                    destination cache will allow to solve this problem
 707                    --ANK (980726)
 708                  */
 709                 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
 710                         goto discard_it;
 711                 hdr = icmp6_hdr(skb);
 712                 orig_hdr = (struct ipv6hdr *) (hdr + 1);
 713                 rt6_pmtu_discovery(&orig_hdr->daddr, &orig_hdr->saddr, dev,
 714                                    ntohl(hdr->icmp6_mtu));
 715
 716                 /*
 717                  *      Drop through to notify
 718                  */
 719
 720         case ICMPV6_DEST_UNREACH:
 721         case ICMPV6_TIME_EXCEED:
 722         case ICMPV6_PARAMPROB:
 723                 icmpv6_notify(skb, type, hdr->icmp6_code, hdr->icmp6_mtu);
 724                 break;
 725
 726         case NDISC_ROUTER_SOLICITATION:
 727         case NDISC_ROUTER_ADVERTISEMENT:
 728         case NDISC_NEIGHBOUR_SOLICITATION:
 729         case NDISC_NEIGHBOUR_ADVERTISEMENT:
 730         case NDISC_REDIRECT:
 731                 ndisc_rcv(skb);
 732                 break;
 733
 734         case ICMPV6_MGM_QUERY:
 735                 igmp6_event_query(skb);
 736                 break;
 737
 738         case ICMPV6_MGM_REPORT:
 739                 igmp6_event_report(skb);
 740                 break;
 741
 742         case ICMPV6_MGM_REDUCTION:
 743         case ICMPV6_NI_QUERY:
 744         case ICMPV6_NI_REPLY:
 745         case ICMPV6_MLD2_REPORT:
 746         case ICMPV6_DHAAD_REQUEST:
 747         case ICMPV6_DHAAD_REPLY:
 748         case ICMPV6_MOBILE_PREFIX_SOL:
 749         case ICMPV6_MOBILE_PREFIX_ADV:
 750                 break;
 751
 752         default:
 753                 LIMIT_NETDEBUG(KERN_DEBUG "icmpv6: msg of unknown type\n");
 754
 755                 /* informational */
 756                 if (type & ICMPV6_INFOMSG_MASK)
 757                         break;
 758
 759                 /*
 760                  * error of unknown type.
 761                  * must pass to upper level
 762                  */
 763
 764                 icmpv6_notify(skb, type, hdr->icmp6_code, hdr->icmp6_mtu);
 765         }
 766
 767         kfree_skb(skb);
 768         return 0;
 769
 770 discard_it:
 771         ICMP6_INC_STATS_BH(idev, ICMP6_MIB_INERRORS);
 772 drop_no_count:
 773         kfree_skb(skb);
 774         return 0;
 775 }
 776
 777 /*
 778  * Special lock-class for __icmpv6_socket:
 779  */
 780 static struct lock_class_key icmpv6_socket_sk_dst_lock_key;
 781
 782 int __init icmpv6_init(struct net_proto_family *ops)
 783 {
 784         struct sock *sk;
 785         int err, i, j;
 786
 787         for_each_possible_cpu(i) {
 788                 err = sock_create_kern(PF_INET6, SOCK_RAW, IPPROTO_ICMPV6,
 789                                        &per_cpu(__icmpv6_socket, i));
 790                 if (err < 0) {
 791                         printk(KERN_ERR
 792                                "Failed to initialize the ICMP6 control socket "
 793                                "(err %d).\n",
 794                                err);
 795                         goto fail;
 796                 }
 797
 798                 sk = per_cpu(__icmpv6_socket, i)->sk;
 799                 sk->sk_allocation = GFP_ATOMIC;
 800                 /*
 801                  * Split off their lock-class, because sk->sk_dst_lock
 802                  * gets used from softirqs, which is safe for
 803                  * __icmpv6_socket (because those never get directly used
 804                  * via userspace syscalls), but unsafe for normal sockets.
 805                  */
 806                 lockdep_set_class(&sk->sk_dst_lock,
 807                                   &icmpv6_socket_sk_dst_lock_key);
 808
 809                 /* Enough space for 2 64K ICMP packets, including
 810                  * sk_buff struct overhead.
 811                  */
 812                 sk->sk_sndbuf =
 813                         (2 * ((64 * 1024) + sizeof(struct sk_buff)));
 814
 815                 sk->sk_prot->unhash(sk);
 816         }
 817
 818
 819         if (inet6_add_protocol(&icmpv6_protocol, IPPROTO_ICMPV6) < 0) {
 820                 printk(KERN_ERR "Failed to register ICMP6 protocol\n");
 821                 err = -EAGAIN;
 822                 goto fail;
 823         }
 824
 825         return 0;
 826
 827  fail:
 828         for (j = 0; j < i; j++) {
 829                 if (!cpu_possible(j))
 830                         continue;
 831                 sock_release(per_cpu(__icmpv6_socket, j));
 832         }
 833
 834         return err;
 835 }
 836
 837 void icmpv6_cleanup(void)
 838 {
 839         int i;
 840
 841         for_each_possible_cpu(i) {
 842                 sock_release(per_cpu(__icmpv6_socket, i));
 843         }
 844         inet6_del_protocol(&icmpv6_protocol, IPPROTO_ICMPV6);
 845 }
 846
 847 static const struct icmp6_err {
 848         int err;
 849         int fatal;
 850 } tab_unreach[] = {
 851         {       /* NOROUTE */
 852                 .err    = ENETUNREACH,
 853                 .fatal  = 0,
 854         },
 855         {       /* ADM_PROHIBITED */
 856                 .err    = EACCES,
 857                 .fatal  = 1,
 858         },
 859         {       /* Was NOT_NEIGHBOUR, now reserved */
 860                 .err    = EHOSTUNREACH,
 861                 .fatal  = 0,
 862         },
 863         {       /* ADDR_UNREACH */
 864                 .err    = EHOSTUNREACH,
 865                 .fatal  = 0,
 866         },
 867         {       /* PORT_UNREACH */
 868                 .err    = ECONNREFUSED,
 869                 .fatal  = 1,
 870         },
 871 };
 872
 873 int icmpv6_err_convert(int type, int code, int *err)
 874 {
 875         int fatal = 0;
 876
 877         *err = EPROTO;
 878
 879         switch (type) {
 880         case ICMPV6_DEST_UNREACH:
 881                 fatal = 1;
 882                 if (code <= ICMPV6_PORT_UNREACH) {
 883                         *err  = tab_unreach[code].err;
 884                         fatal = tab_unreach[code].fatal;
 885                 }
 886                 break;
 887
 888         case ICMPV6_PKT_TOOBIG:
 889                 *err = EMSGSIZE;
 890                 break;
 891
 892         case ICMPV6_PARAMPROB:
 893                 *err = EPROTO;
 894                 fatal = 1;
 895                 break;
 896
 897         case ICMPV6_TIME_EXCEED:
 898                 *err = EHOSTUNREACH;
 899                 break;
 900         }
 901
 902         return fatal;
 903 }
 904
 905 EXPORT_SYMBOL(icmpv6_err_convert);
 906
 907 #ifdef CONFIG_SYSCTL
 908 ctl_table ipv6_icmp_table_template[] = {
 909         {
 910                 .ctl_name       = NET_IPV6_ICMP_RATELIMIT,
 911                 .procname       = "ratelimit",
 912                 .data           = &init_net.ipv6.sysctl.icmpv6_time,
 913                 .maxlen         = sizeof(int),
 914                 .mode           = 0644,
 915                 .proc_handler   = &proc_dointvec
 916         },
 917         { .ctl_name = 0 },
 918 };
 919
 920 struct ctl_table *ipv6_icmp_sysctl_init(struct net *net)
 921 {
 922         struct ctl_table *table;
 923
 924         table = kmemdup(ipv6_icmp_table_template,
 925                         sizeof(ipv6_icmp_table_template),
 926                         GFP_KERNEL);
 927         return table;
 928 }
 929 #endif
 930