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/sched.h>
  41 #include <linux/sockios.h>
  42 #include <linux/net.h>
  43 #include <linux/skbuff.h>
  44 #include <linux/init.h>
  45 #include <linux/netfilter.h>
  46
  47 #ifdef CONFIG_SYSCTL
  48 #include <linux/sysctl.h>
  49 #endif
  50
  51 #include <linux/inet.h>
  52 #include <linux/netdevice.h>
  53 #include <linux/icmpv6.h>
  54
  55 #include <net/ip.h>
  56 #include <net/sock.h>
  57
  58 #include <net/ipv6.h>
  59 #include <net/ip6_checksum.h>
  60 #include <net/protocol.h>
  61 #include <net/raw.h>
  62 #include <net/rawv6.h>
  63 #include <net/transp_v6.h>
  64 #include <net/ip6_route.h>
  65 #include <net/addrconf.h>
  66 #include <net/icmp.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
  73 /*
  74  *      The ICMP socket(s). This is the most convenient way to flow control
  75  *      our ICMP output as well as maintain a clean interface throughout
  76  *      all layers. All Socketless IP sends will soon be gone.
  77  *
  78  *      On SMP we have one ICMP socket per-cpu.
  79  */
  80 static DEFINE_PER_CPU(struct socket *, __icmpv6_socket) = NULL;
  81 #define icmpv6_socket   __get_cpu_var(__icmpv6_socket)
  82
  83 static int icmpv6_rcv(struct sk_buff **pskb);
  84
  85 static struct inet6_protocol icmpv6_protocol = {
  86         .handler        =       icmpv6_rcv,
  87         .flags          =       INET6_PROTO_FINAL,
  88 };
  89
  90 static __inline__ int icmpv6_xmit_lock(void)
  91 {
  92         local_bh_disable();
  93
  94         if (unlikely(!spin_trylock(&icmpv6_socket->sk->sk_lock.slock))) {
  95                 /* This can happen if the output path (f.e. SIT or
  96                  * ip6ip6 tunnel) signals dst_link_failure() for an
  97                  * outgoing ICMP6 packet.
  98                  */
  99                 local_bh_enable();
 100                 return 1;
 101         }
 102         return 0;
 103 }
 104
 105 static __inline__ void icmpv6_xmit_unlock(void)
 106 {
 107         spin_unlock_bh(&icmpv6_socket->sk->sk_lock.slock);
 108 }
 109
 110 /*
 111  * Slightly more convenient version of icmpv6_send.
 112  */
 113 void icmpv6_param_prob(struct sk_buff *skb, int code, int pos)
 114 {
 115         icmpv6_send(skb, ICMPV6_PARAMPROB, code, pos, skb->dev);
 116         kfree_skb(skb);
 117 }
 118
 119 /*
 120  * Figure out, may we reply to this packet with icmp error.
 121  *
 122  * We do not reply, if:
 123  *      - it was icmp error message.
 124  *      - it is truncated, so that it is known, that protocol is ICMPV6
 125  *        (i.e. in the middle of some exthdr)
 126  *
 127  *      --ANK (980726)
 128  */
 129
 130 static int is_ineligible(struct sk_buff *skb)
 131 {
 132         int ptr = (u8*)(skb->nh.ipv6h+1) - skb->data;
 133         int len = skb->len - ptr;
 134         __u8 nexthdr = skb->nh.ipv6h->nexthdr;
 135
 136         if (len < 0)
 137                 return 1;
 138
 139         ptr = ipv6_skip_exthdr(skb, ptr, &nexthdr);
 140         if (ptr < 0)
 141                 return 0;
 142         if (nexthdr == IPPROTO_ICMPV6) {
 143                 u8 _type, *tp;
 144                 tp = skb_header_pointer(skb,
 145                         ptr+offsetof(struct icmp6hdr, icmp6_type),
 146                         sizeof(_type), &_type);
 147                 if (tp == NULL ||
 148                     !(*tp & ICMPV6_INFOMSG_MASK))
 149                         return 1;
 150         }
 151         return 0;
 152 }
 153
 154 static int sysctl_icmpv6_time __read_mostly = 1*HZ;
 155
 156 /*
 157  * Check the ICMP output rate limit
 158  */
 159 static inline int icmpv6_xrlim_allow(struct sock *sk, int type,
 160                                      struct flowi *fl)
 161 {
 162         struct dst_entry *dst;
 163         int res = 0;
 164
 165         /* Informational messages are not limited. */
 166         if (type & ICMPV6_INFOMSG_MASK)
 167                 return 1;
 168
 169         /* Do not limit pmtu discovery, it would break it. */
 170         if (type == ICMPV6_PKT_TOOBIG)
 171                 return 1;
 172
 173         /*
 174          * Look up the output route.
 175          * XXX: perhaps the expire for routing entries cloned by
 176          * this lookup should be more aggressive (not longer than timeout).
 177          */
 178         dst = ip6_route_output(sk, fl);
 179         if (dst->error) {
 180                 IP6_INC_STATS(ip6_dst_idev(dst),
 181                               IPSTATS_MIB_OUTNOROUTES);
 182         } else if (dst->dev && (dst->dev->flags&IFF_LOOPBACK)) {
 183                 res = 1;
 184         } else {
 185                 struct rt6_info *rt = (struct rt6_info *)dst;
 186                 int tmo = sysctl_icmpv6_time;
 187
 188                 /* Give more bandwidth to wider prefixes. */
 189                 if (rt->rt6i_dst.plen < 128)
 190                         tmo >>= ((128 - rt->rt6i_dst.plen)>>5);
 191
 192                 res = xrlim_allow(dst, tmo);
 193         }
 194         dst_release(dst);
 195         return res;
 196 }
 197
 198 /*
 199  *      an inline helper for the "simple" if statement below
 200  *      checks if parameter problem report is caused by an
 201  *      unrecognized IPv6 option that has the Option Type
 202  *      highest-order two bits set to 10
 203  */
 204
 205 static __inline__ int opt_unrec(struct sk_buff *skb, __u32 offset)
 206 {
 207         u8 _optval, *op;
 208
 209         offset += skb->nh.raw - skb->data;
 210         op = skb_header_pointer(skb, offset, sizeof(_optval), &_optval);
 211         if (op == NULL)
 212                 return 1;
 213         return (*op & 0xC0) == 0x80;
 214 }
 215
 216 static int icmpv6_push_pending_frames(struct sock *sk, struct flowi *fl, struct icmp6hdr *thdr, int len)
 217 {
 218         struct sk_buff *skb;
 219         struct icmp6hdr *icmp6h;
 220         int err = 0;
 221
 222         if ((skb = skb_peek(&sk->sk_write_queue)) == NULL)
 223                 goto out;
 224
 225         icmp6h = (struct icmp6hdr*) skb->h.raw;
 226         memcpy(icmp6h, thdr, sizeof(struct icmp6hdr));
 227         icmp6h->icmp6_cksum = 0;
 228
 229         if (skb_queue_len(&sk->sk_write_queue) == 1) {
 230                 skb->csum = csum_partial((char *)icmp6h,
 231                                         sizeof(struct icmp6hdr), skb->csum);
 232                 icmp6h->icmp6_cksum = csum_ipv6_magic(&fl->fl6_src,
 233                                                       &fl->fl6_dst,
 234                                                       len, fl->proto,
 235                                                       skb->csum);
 236         } else {
 237                 __wsum tmp_csum = 0;
 238
 239                 skb_queue_walk(&sk->sk_write_queue, skb) {
 240                         tmp_csum = csum_add(tmp_csum, skb->csum);
 241                 }
 242
 243                 tmp_csum = csum_partial((char *)icmp6h,
 244                                         sizeof(struct icmp6hdr), tmp_csum);
 245                 icmp6h->icmp6_cksum = csum_ipv6_magic(&fl->fl6_src,
 246                                                       &fl->fl6_dst,
 247                                                       len, fl->proto,
 248                                                       tmp_csum);
 249         }
 250         ip6_push_pending_frames(sk);
 251 out:
 252         return err;
 253 }
 254
 255 struct icmpv6_msg {
 256         struct sk_buff  *skb;
 257         int             offset;
 258         uint8_t         type;
 259 };
 260
 261 static int icmpv6_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb)
 262 {
 263         struct icmpv6_msg *msg = (struct icmpv6_msg *) from;
 264         struct sk_buff *org_skb = msg->skb;
 265         __wsum csum = 0;
 266
 267         csum = skb_copy_and_csum_bits(org_skb, msg->offset + offset,
 268                                       to, len, csum);
 269         skb->csum = csum_block_add(skb->csum, csum, odd);
 270         if (!(msg->type & ICMPV6_INFOMSG_MASK))
 271                 nf_ct_attach(skb, org_skb);
 272         return 0;
 273 }
 274
 275 #ifdef CONFIG_IPV6_MIP6
 276 static void mip6_addr_swap(struct sk_buff *skb)
 277 {
 278         struct ipv6hdr *iph = skb->nh.ipv6h;
 279         struct inet6_skb_parm *opt = IP6CB(skb);
 280         struct ipv6_destopt_hao *hao;
 281         struct in6_addr tmp;
 282         int off;
 283
 284         if (opt->dsthao) {
 285                 off = ipv6_find_tlv(skb, opt->dsthao, IPV6_TLV_HAO);
 286                 if (likely(off >= 0)) {
 287                         hao = (struct ipv6_destopt_hao *)(skb->nh.raw + off);
 288                         ipv6_addr_copy(&tmp, &iph->saddr);
 289                         ipv6_addr_copy(&iph->saddr, &hao->addr);
 290                         ipv6_addr_copy(&hao->addr, &tmp);
 291                 }
 292         }
 293 }
 294 #else
 295 static inline void mip6_addr_swap(struct sk_buff *skb) {}
 296 #endif
 297
 298 /*
 299  *      Send an ICMP message in response to a packet in error
 300  */
 301 void icmpv6_send(struct sk_buff *skb, int type, int code, __u32 info,
 302                  struct net_device *dev)
 303 {
 304         struct inet6_dev *idev = NULL;
 305         struct ipv6hdr *hdr = skb->nh.ipv6h;
 306         struct sock *sk;
 307         struct ipv6_pinfo *np;
 308         struct in6_addr *saddr = NULL;
 309         struct dst_entry *dst;
 310         struct icmp6hdr tmp_hdr;
 311         struct flowi fl;
 312         struct icmpv6_msg msg;
 313         int iif = 0;
 314         int addr_type = 0;
 315         int len;
 316         int hlimit, tclass;
 317         int err = 0;
 318
 319         if ((u8*)hdr < skb->head || (u8*)(hdr+1) > skb->tail)
 320                 return;
 321
 322         /*
 323          *      Make sure we respect the rules
 324          *      i.e. RFC 1885 2.4(e)
 325          *      Rule (e.1) is enforced by not using icmpv6_send
 326          *      in any code that processes icmp errors.
 327          */
 328         addr_type = ipv6_addr_type(&hdr->daddr);
 329
 330         if (ipv6_chk_addr(&hdr->daddr, skb->dev, 0))
 331                 saddr = &hdr->daddr;
 332
 333         /*
 334          *      Dest addr check
 335          */
 336
 337         if ((addr_type & IPV6_ADDR_MULTICAST || skb->pkt_type != PACKET_HOST)) {
 338                 if (type != ICMPV6_PKT_TOOBIG &&
 339                     !(type == ICMPV6_PARAMPROB &&
 340                       code == ICMPV6_UNK_OPTION &&
 341                       (opt_unrec(skb, info))))
 342                         return;
 343
 344                 saddr = NULL;
 345         }
 346
 347         addr_type = ipv6_addr_type(&hdr->saddr);
 348
 349         /*
 350          *      Source addr check
 351          */
 352
 353         if (addr_type & IPV6_ADDR_LINKLOCAL)
 354                 iif = skb->dev->ifindex;
 355
 356         /*
 357          *      Must not send error if the source does not uniquely
 358          *      identify a single node (RFC2463 Section 2.4).
 359          *      We check unspecified / multicast addresses here,
 360          *      and anycast addresses will be checked later.
 361          */
 362         if ((addr_type == IPV6_ADDR_ANY) || (addr_type & IPV6_ADDR_MULTICAST)) {
 363                 LIMIT_NETDEBUG(KERN_DEBUG "icmpv6_send: addr_any/mcast source\n");
 364                 return;
 365         }
 366
 367         /*
 368          *      Never answer to a ICMP packet.
 369          */
 370         if (is_ineligible(skb)) {
 371                 LIMIT_NETDEBUG(KERN_DEBUG "icmpv6_send: no reply to icmp error\n");
 372                 return;
 373         }
 374
 375         mip6_addr_swap(skb);
 376
 377         memset(&fl, 0, sizeof(fl));
 378         fl.proto = IPPROTO_ICMPV6;
 379         ipv6_addr_copy(&fl.fl6_dst, &hdr->saddr);
 380         if (saddr)
 381                 ipv6_addr_copy(&fl.fl6_src, saddr);
 382         fl.oif = iif;
 383         fl.fl_icmp_type = type;
 384         fl.fl_icmp_code = code;
 385         security_skb_classify_flow(skb, &fl);
 386
 387         if (icmpv6_xmit_lock())
 388                 return;
 389
 390         sk = icmpv6_socket->sk;
 391         np = inet6_sk(sk);
 392
 393         if (!icmpv6_xrlim_allow(sk, type, &fl))
 394                 goto out;
 395
 396         tmp_hdr.icmp6_type = type;
 397         tmp_hdr.icmp6_code = code;
 398         tmp_hdr.icmp6_cksum = 0;
 399         tmp_hdr.icmp6_pointer = htonl(info);
 400
 401         if (!fl.oif && ipv6_addr_is_multicast(&fl.fl6_dst))
 402                 fl.oif = np->mcast_oif;
 403
 404         err = ip6_dst_lookup(sk, &dst, &fl);
 405         if (err)
 406                 goto out;
 407
 408         /*
 409          * We won't send icmp if the destination is known
 410          * anycast.
 411          */
 412         if (((struct rt6_info *)dst)->rt6i_flags & RTF_ANYCAST) {
 413                 LIMIT_NETDEBUG(KERN_DEBUG "icmpv6_send: acast source\n");
 414                 goto out_dst_release;
 415         }
 416
 417         if ((err = xfrm_lookup(&dst, &fl, sk, 0)) < 0)
 418                 goto out;
 419
 420         if (ipv6_addr_is_multicast(&fl.fl6_dst))
 421                 hlimit = np->mcast_hops;
 422         else
 423                 hlimit = np->hop_limit;
 424         if (hlimit < 0)
 425                 hlimit = dst_metric(dst, RTAX_HOPLIMIT);
 426         if (hlimit < 0)
 427                 hlimit = ipv6_get_hoplimit(dst->dev);
 428
 429         tclass = np->tclass;
 430         if (tclass < 0)
 431                 tclass = 0;
 432
 433         msg.skb = skb;
 434         msg.offset = skb->nh.raw - skb->data;
 435         msg.type = type;
 436
 437         len = skb->len - msg.offset;
 438         len = min_t(unsigned int, len, IPV6_MIN_MTU - sizeof(struct ipv6hdr) -sizeof(struct icmp6hdr));
 439         if (len < 0) {
 440                 LIMIT_NETDEBUG(KERN_DEBUG "icmp: len problem\n");
 441                 goto out_dst_release;
 442         }
 443
 444         idev = in6_dev_get(skb->dev);
 445
 446         err = ip6_append_data(sk, icmpv6_getfrag, &msg,
 447                               len + sizeof(struct icmp6hdr),
 448                               sizeof(struct icmp6hdr),
 449                               hlimit, tclass, NULL, &fl, (struct rt6_info*)dst,
 450                               MSG_DONTWAIT);
 451         if (err) {
 452                 ip6_flush_pending_frames(sk);
 453                 goto out_put;
 454         }
 455         err = icmpv6_push_pending_frames(sk, &fl, &tmp_hdr, len + sizeof(struct icmp6hdr));
 456
 457         if (type >= ICMPV6_DEST_UNREACH && type <= ICMPV6_PARAMPROB)
 458                 ICMP6_INC_STATS_OFFSET_BH(idev, ICMP6_MIB_OUTDESTUNREACHS, type - ICMPV6_DEST_UNREACH);
 459         ICMP6_INC_STATS_BH(idev, ICMP6_MIB_OUTMSGS);
 460
 461 out_put:
 462         if (likely(idev != NULL))
 463                 in6_dev_put(idev);
 464 out_dst_release:
 465         dst_release(dst);
 466 out:
 467         icmpv6_xmit_unlock();
 468 }
 469
 470 static void icmpv6_echo_reply(struct sk_buff *skb)
 471 {
 472         struct sock *sk;
 473         struct inet6_dev *idev;
 474         struct ipv6_pinfo *np;
 475         struct in6_addr *saddr = NULL;
 476         struct icmp6hdr *icmph = (struct icmp6hdr *) skb->h.raw;
 477         struct icmp6hdr tmp_hdr;
 478         struct flowi fl;
 479         struct icmpv6_msg msg;
 480         struct dst_entry *dst;
 481         int err = 0;
 482         int hlimit;
 483         int tclass;
 484
 485         saddr = &skb->nh.ipv6h->daddr;
 486
 487         if (!ipv6_unicast_destination(skb))
 488                 saddr = NULL;
 489
 490         memcpy(&tmp_hdr, icmph, sizeof(tmp_hdr));
 491         tmp_hdr.icmp6_type = ICMPV6_ECHO_REPLY;
 492
 493         memset(&fl, 0, sizeof(fl));
 494         fl.proto = IPPROTO_ICMPV6;
 495         ipv6_addr_copy(&fl.fl6_dst, &skb->nh.ipv6h->saddr);
 496         if (saddr)
 497                 ipv6_addr_copy(&fl.fl6_src, saddr);
 498         fl.oif = skb->dev->ifindex;
 499         fl.fl_icmp_type = ICMPV6_ECHO_REPLY;
 500         security_skb_classify_flow(skb, &fl);
 501
 502         if (icmpv6_xmit_lock())
 503                 return;
 504
 505         sk = icmpv6_socket->sk;
 506         np = inet6_sk(sk);
 507
 508         if (!fl.oif && ipv6_addr_is_multicast(&fl.fl6_dst))
 509                 fl.oif = np->mcast_oif;
 510
 511         err = ip6_dst_lookup(sk, &dst, &fl);
 512         if (err)
 513                 goto out;
 514         if ((err = xfrm_lookup(&dst, &fl, sk, 0)) < 0)
 515                 goto out;
 516
 517         if (ipv6_addr_is_multicast(&fl.fl6_dst))
 518                 hlimit = np->mcast_hops;
 519         else
 520                 hlimit = np->hop_limit;
 521         if (hlimit < 0)
 522                 hlimit = dst_metric(dst, RTAX_HOPLIMIT);
 523         if (hlimit < 0)
 524                 hlimit = ipv6_get_hoplimit(dst->dev);
 525
 526         tclass = np->tclass;
 527         if (tclass < 0)
 528                 tclass = 0;
 529
 530         idev = in6_dev_get(skb->dev);
 531
 532         msg.skb = skb;
 533         msg.offset = 0;
 534         msg.type = ICMPV6_ECHO_REPLY;
 535
 536         err = ip6_append_data(sk, icmpv6_getfrag, &msg, skb->len + sizeof(struct icmp6hdr),
 537                                 sizeof(struct icmp6hdr), hlimit, tclass, NULL, &fl,
 538                                 (struct rt6_info*)dst, MSG_DONTWAIT);
 539
 540         if (err) {
 541                 ip6_flush_pending_frames(sk);
 542                 goto out_put;
 543         }
 544         err = icmpv6_push_pending_frames(sk, &fl, &tmp_hdr, skb->len + sizeof(struct icmp6hdr));
 545
 546         ICMP6_INC_STATS_BH(idev, ICMP6_MIB_OUTECHOREPLIES);
 547         ICMP6_INC_STATS_BH(idev, ICMP6_MIB_OUTMSGS);
 548
 549 out_put:
 550         if (likely(idev != NULL))
 551                 in6_dev_put(idev);
 552         dst_release(dst);
 553 out:
 554         icmpv6_xmit_unlock();
 555 }
 556
 557 static void icmpv6_notify(struct sk_buff *skb, int type, int code, __be32 info)
 558 {
 559         struct in6_addr *saddr, *daddr;
 560         struct inet6_protocol *ipprot;
 561         struct sock *sk;
 562         int inner_offset;
 563         int hash;
 564         u8 nexthdr;
 565
 566         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
 567                 return;
 568
 569         nexthdr = ((struct ipv6hdr *)skb->data)->nexthdr;
 570         if (ipv6_ext_hdr(nexthdr)) {
 571                 /* now skip over extension headers */
 572                 inner_offset = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &nexthdr);
 573                 if (inner_offset<0)
 574                         return;
 575         } else {
 576                 inner_offset = sizeof(struct ipv6hdr);
 577         }
 578
 579         /* Checkin header including 8 bytes of inner protocol header. */
 580         if (!pskb_may_pull(skb, inner_offset+8))
 581                 return;
 582
 583         saddr = &skb->nh.ipv6h->saddr;
 584         daddr = &skb->nh.ipv6h->daddr;
 585
 586         /* BUGGG_FUTURE: we should try to parse exthdrs in this packet.
 587            Without this we will not able f.e. to make source routed
 588            pmtu discovery.
 589            Corresponding argument (opt) to notifiers is already added.
 590            --ANK (980726)
 591          */
 592
 593         hash = nexthdr & (MAX_INET_PROTOS - 1);
 594
 595         rcu_read_lock();
 596         ipprot = rcu_dereference(inet6_protos[hash]);
 597         if (ipprot && ipprot->err_handler)
 598                 ipprot->err_handler(skb, NULL, type, code, inner_offset, info);
 599         rcu_read_unlock();
 600
 601         read_lock(&raw_v6_lock);
 602         if ((sk = sk_head(&raw_v6_htable[hash])) != NULL) {
 603                 while((sk = __raw_v6_lookup(sk, nexthdr, daddr, saddr,
 604                                             IP6CB(skb)->iif))) {
 605                         rawv6_err(sk, skb, NULL, type, code, inner_offset, info);
 606                         sk = sk_next(sk);
 607                 }
 608         }
 609         read_unlock(&raw_v6_lock);
 610 }
 611
 612 /*
 613  *      Handle icmp messages
 614  */
 615
 616 static int icmpv6_rcv(struct sk_buff **pskb)
 617 {
 618         struct sk_buff *skb = *pskb;
 619         struct net_device *dev = skb->dev;
 620         struct inet6_dev *idev = __in6_dev_get(dev);
 621         struct in6_addr *saddr, *daddr;
 622         struct ipv6hdr *orig_hdr;
 623         struct icmp6hdr *hdr;
 624         int type;
 625
 626         ICMP6_INC_STATS_BH(idev, ICMP6_MIB_INMSGS);
 627
 628         saddr = &skb->nh.ipv6h->saddr;
 629         daddr = &skb->nh.ipv6h->daddr;
 630
 631         /* Perform checksum. */
 632         switch (skb->ip_summed) {
 633         case CHECKSUM_COMPLETE:
 634                 if (!csum_ipv6_magic(saddr, daddr, skb->len, IPPROTO_ICMPV6,
 635                                      skb->csum))
 636                         break;
 637                 /* fall through */
 638         case CHECKSUM_NONE:
 639                 skb->csum = ~csum_unfold(csum_ipv6_magic(saddr, daddr, skb->len,
 640                                              IPPROTO_ICMPV6, 0));
 641                 if (__skb_checksum_complete(skb)) {
 642                         LIMIT_NETDEBUG(KERN_DEBUG "ICMPv6 checksum failed [" NIP6_FMT " > " NIP6_FMT "]\n",
 643                                        NIP6(*saddr), NIP6(*daddr));
 644                         goto discard_it;
 645                 }
 646         }
 647
 648         if (!pskb_pull(skb, sizeof(struct icmp6hdr)))
 649                 goto discard_it;
 650
 651         hdr = (struct icmp6hdr *) skb->h.raw;
 652
 653         type = hdr->icmp6_type;
 654
 655         if (type >= ICMPV6_DEST_UNREACH && type <= ICMPV6_PARAMPROB)
 656                 ICMP6_INC_STATS_OFFSET_BH(idev, ICMP6_MIB_INDESTUNREACHS, type - ICMPV6_DEST_UNREACH);
 657         else if (type >= ICMPV6_ECHO_REQUEST && type <= NDISC_REDIRECT)
 658                 ICMP6_INC_STATS_OFFSET_BH(idev, ICMP6_MIB_INECHOS, type - ICMPV6_ECHO_REQUEST);
 659
 660         switch (type) {
 661         case ICMPV6_ECHO_REQUEST:
 662                 icmpv6_echo_reply(skb);
 663                 break;
 664
 665         case ICMPV6_ECHO_REPLY:
 666                 /* we couldn't care less */
 667                 break;
 668
 669         case ICMPV6_PKT_TOOBIG:
 670                 /* BUGGG_FUTURE: if packet contains rthdr, we cannot update
 671                    standard destination cache. Seems, only "advanced"
 672                    destination cache will allow to solve this problem
 673                    --ANK (980726)
 674                  */
 675                 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
 676                         goto discard_it;
 677                 hdr = (struct icmp6hdr *) skb->h.raw;
 678                 orig_hdr = (struct ipv6hdr *) (hdr + 1);
 679                 rt6_pmtu_discovery(&orig_hdr->daddr, &orig_hdr->saddr, dev,
 680                                    ntohl(hdr->icmp6_mtu));
 681
 682                 /*
 683                  *      Drop through to notify
 684                  */
 685
 686         case ICMPV6_DEST_UNREACH:
 687         case ICMPV6_TIME_EXCEED:
 688         case ICMPV6_PARAMPROB:
 689                 icmpv6_notify(skb, type, hdr->icmp6_code, hdr->icmp6_mtu);
 690                 break;
 691
 692         case NDISC_ROUTER_SOLICITATION:
 693         case NDISC_ROUTER_ADVERTISEMENT:
 694         case NDISC_NEIGHBOUR_SOLICITATION:
 695         case NDISC_NEIGHBOUR_ADVERTISEMENT:
 696         case NDISC_REDIRECT:
 697                 ndisc_rcv(skb);
 698                 break;
 699
 700         case ICMPV6_MGM_QUERY:
 701                 igmp6_event_query(skb);
 702                 break;
 703
 704         case ICMPV6_MGM_REPORT:
 705                 igmp6_event_report(skb);
 706                 break;
 707
 708         case ICMPV6_MGM_REDUCTION:
 709         case ICMPV6_NI_QUERY:
 710         case ICMPV6_NI_REPLY:
 711         case ICMPV6_MLD2_REPORT:
 712         case ICMPV6_DHAAD_REQUEST:
 713         case ICMPV6_DHAAD_REPLY:
 714         case ICMPV6_MOBILE_PREFIX_SOL:
 715         case ICMPV6_MOBILE_PREFIX_ADV:
 716                 break;
 717
 718         default:
 719                 LIMIT_NETDEBUG(KERN_DEBUG "icmpv6: msg of unknown type\n");
 720
 721                 /* informational */
 722                 if (type & ICMPV6_INFOMSG_MASK)
 723                         break;
 724
 725                 /*
 726                  * error of unknown type.
 727                  * must pass to upper level
 728                  */
 729
 730                 icmpv6_notify(skb, type, hdr->icmp6_code, hdr->icmp6_mtu);
 731         };
 732         kfree_skb(skb);
 733         return 0;
 734
 735 discard_it:
 736         ICMP6_INC_STATS_BH(idev, ICMP6_MIB_INERRORS);
 737         kfree_skb(skb);
 738         return 0;
 739 }
 740
 741 /*
 742  * Special lock-class for __icmpv6_socket:
 743  */
 744 static struct lock_class_key icmpv6_socket_sk_dst_lock_key;
 745
 746 int __init icmpv6_init(struct net_proto_family *ops)
 747 {
 748         struct sock *sk;
 749         int err, i, j;
 750
 751         for_each_possible_cpu(i) {
 752                 err = sock_create_kern(PF_INET6, SOCK_RAW, IPPROTO_ICMPV6,
 753                                        &per_cpu(__icmpv6_socket, i));
 754                 if (err < 0) {
 755                         printk(KERN_ERR
 756                                "Failed to initialize the ICMP6 control socket "
 757                                "(err %d).\n",
 758                                err);
 759                         goto fail;
 760                 }
 761
 762                 sk = per_cpu(__icmpv6_socket, i)->sk;
 763                 sk->sk_allocation = GFP_ATOMIC;
 764                 /*
 765                  * Split off their lock-class, because sk->sk_dst_lock
 766                  * gets used from softirqs, which is safe for
 767                  * __icmpv6_socket (because those never get directly used
 768                  * via userspace syscalls), but unsafe for normal sockets.
 769                  */
 770                 lockdep_set_class(&sk->sk_dst_lock,
 771                                   &icmpv6_socket_sk_dst_lock_key);
 772
 773                 /* Enough space for 2 64K ICMP packets, including
 774                  * sk_buff struct overhead.
 775                  */
 776                 sk->sk_sndbuf =
 777                         (2 * ((64 * 1024) + sizeof(struct sk_buff)));
 778
 779                 sk->sk_prot->unhash(sk);
 780         }
 781
 782
 783         if (inet6_add_protocol(&icmpv6_protocol, IPPROTO_ICMPV6) < 0) {
 784                 printk(KERN_ERR "Failed to register ICMP6 protocol\n");
 785                 err = -EAGAIN;
 786                 goto fail;
 787         }
 788
 789         return 0;
 790
 791  fail:
 792         for (j = 0; j < i; j++) {
 793                 if (!cpu_possible(j))
 794                         continue;
 795                 sock_release(per_cpu(__icmpv6_socket, j));
 796         }
 797
 798         return err;
 799 }
 800
 801 void icmpv6_cleanup(void)
 802 {
 803         int i;
 804
 805         for_each_possible_cpu(i) {
 806                 sock_release(per_cpu(__icmpv6_socket, i));
 807         }
 808         inet6_del_protocol(&icmpv6_protocol, IPPROTO_ICMPV6);
 809 }
 810
 811 static const struct icmp6_err {
 812         int err;
 813         int fatal;
 814 } tab_unreach[] = {
 815         {       /* NOROUTE */
 816                 .err    = ENETUNREACH,
 817                 .fatal  = 0,
 818         },
 819         {       /* ADM_PROHIBITED */
 820                 .err    = EACCES,
 821                 .fatal  = 1,
 822         },
 823         {       /* Was NOT_NEIGHBOUR, now reserved */
 824                 .err    = EHOSTUNREACH,
 825                 .fatal  = 0,
 826         },
 827         {       /* ADDR_UNREACH */
 828                 .err    = EHOSTUNREACH,
 829                 .fatal  = 0,
 830         },
 831         {       /* PORT_UNREACH */
 832                 .err    = ECONNREFUSED,
 833                 .fatal  = 1,
 834         },
 835 };
 836
 837 int icmpv6_err_convert(int type, int code, int *err)
 838 {
 839         int fatal = 0;
 840
 841         *err = EPROTO;
 842
 843         switch (type) {
 844         case ICMPV6_DEST_UNREACH:
 845                 fatal = 1;
 846                 if (code <= ICMPV6_PORT_UNREACH) {
 847                         *err  = tab_unreach[code].err;
 848                         fatal = tab_unreach[code].fatal;
 849                 }
 850                 break;
 851
 852         case ICMPV6_PKT_TOOBIG:
 853                 *err = EMSGSIZE;
 854                 break;
 855
 856         case ICMPV6_PARAMPROB:
 857                 *err = EPROTO;
 858                 fatal = 1;
 859                 break;
 860
 861         case ICMPV6_TIME_EXCEED:
 862                 *err = EHOSTUNREACH;
 863                 break;
 864         };
 865
 866         return fatal;
 867 }
 868
 869 #ifdef CONFIG_SYSCTL
 870 ctl_table ipv6_icmp_table[] = {
 871         {
 872                 .ctl_name       = NET_IPV6_ICMP_RATELIMIT,
 873                 .procname       = "ratelimit",
 874                 .data           = &sysctl_icmpv6_time,
 875                 .maxlen         = sizeof(int),
 876                 .mode           = 0644,
 877                 .proc_handler   = &proc_dointvec
 878         },
 879         { .ctl_name = 0 },
 880 };
 881 #endif
 882