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  *      Based on net/ipv4/icmp.c
   9  *
  10  *      RFC 1885
  11  *
  12  *      This program is free software; you can redistribute it and/or
  13  *      modify it under the terms of the GNU General Public License
  14  *      as published by the Free Software Foundation; either version
  15  *      2 of the License, or (at your option) any later version.
  16  */
  17
  18 /*
  19  *      Changes:
  20  *
  21  *      Andi Kleen              :       exception handling
  22  *      Andi Kleen                      add rate limits. never reply to a icmp.
  23  *                                      add more length checks and other fixes.
  24  *      yoshfuji                :       ensure to sent parameter problem for
  25  *                                      fragments.
  26  *      YOSHIFUJI Hideaki @USAGI:       added sysctl for icmp rate limit.
  27  *      Randy Dunlap and
  28  *      YOSHIFUJI Hideaki @USAGI:       Per-interface statistics support
  29  *      Kazunori MIYAZAWA @USAGI:       change output process to use ip6_append_data
  30  */
  31
  32 #include <linux/module.h>
  33 #include <linux/errno.h>
  34 #include <linux/types.h>
  35 #include <linux/socket.h>
  36 #include <linux/in.h>
  37 #include <linux/kernel.h>
  38 #include <linux/sockios.h>
  39 #include <linux/net.h>
  40 #include <linux/skbuff.h>
  41 #include <linux/init.h>
  42 #include <linux/netfilter.h>
  43 #include <linux/slab.h>
  44
  45 #ifdef CONFIG_SYSCTL
  46 #include <linux/sysctl.h>
  47 #endif
  48
  49 #include <linux/inet.h>
  50 #include <linux/netdevice.h>
  51 #include <linux/icmpv6.h>
  52
  53 #include <net/ip.h>
  54 #include <net/sock.h>
  55
  56 #include <net/ipv6.h>
  57 #include <net/ip6_checksum.h>
  58 #include <net/protocol.h>
  59 #include <net/raw.h>
  60 #include <net/rawv6.h>
  61 #include <net/transp_v6.h>
  62 #include <net/ip6_route.h>
  63 #include <net/addrconf.h>
  64 #include <net/icmp.h>
  65 #include <net/xfrm.h>
  66 #include <net/inet_common.h>
  67
  68 #include <asm/uaccess.h>
  69 #include <asm/system.h>
  70
  71 /*
  72  *      The ICMP socket(s). This is the most convenient way to flow control
  73  *      our ICMP output as well as maintain a clean interface throughout
  74  *      all layers. All Socketless IP sends will soon be gone.
  75  *
  76  *      On SMP we have one ICMP socket per-cpu.
  77  */
  78 static inline struct sock *icmpv6_sk(struct net *net)
  79 {
  80         return net->ipv6.icmp_sk[smp_processor_id()];
  81 }
  82
  83 static int icmpv6_rcv(struct sk_buff *skb);
  84
  85 static const struct inet6_protocol icmpv6_protocol = {
  86         .handler        =       icmpv6_rcv,
  87         .flags          =       INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
  88 };
  89
  90 static __inline__ struct sock *icmpv6_xmit_lock(struct net *net)
  91 {
  92         struct sock *sk;
  93
  94         local_bh_disable();
  95
  96         sk = icmpv6_sk(net);
  97         if (unlikely(!spin_trylock(&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 NULL;
 104         }
 105         return sk;
 106 }
 107
 108 static __inline__ void icmpv6_xmit_unlock(struct sock *sk)
 109 {
 110         spin_unlock_bh(&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, u8 code, int pos)
 117 {
 118         icmpv6_send(skb, ICMPV6_PARAMPROB, code, pos);
 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, u8 type,
 161                                      struct flowi *fl)
 162 {
 163         struct dst_entry *dst;
 164         struct net *net = sock_net(sk);
 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(net, sk, fl);
 181         if (dst->error) {
 182                 IP6_INC_STATS(net, 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 = net->ipv6.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(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(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, u8 type, u8 code, __u32 info)
 305 {
 306         struct net *net = dev_net(skb->dev);
 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 dst_entry *dst2;
 314         struct icmp6hdr tmp_hdr;
 315         struct flowi fl;
 316         struct flowi fl2;
 317         struct icmpv6_msg msg;
 318         int iif = 0;
 319         int addr_type = 0;
 320         int len;
 321         int hlimit;
 322         int err = 0;
 323
 324         if ((u8 *)hdr < skb->head ||
 325             (skb->network_header + sizeof(*hdr)) > skb->tail)
 326                 return;
 327
 328         /*
 329          *      Make sure we respect the rules
 330          *      i.e. RFC 1885 2.4(e)
 331          *      Rule (e.1) is enforced by not using icmpv6_send
 332          *      in any code that processes icmp errors.
 333          */
 334         addr_type = ipv6_addr_type(&hdr->daddr);
 335
 336         if (ipv6_chk_addr(net, &hdr->daddr, skb->dev, 0))
 337                 saddr = &hdr->daddr;
 338
 339         /*
 340          *      Dest addr check
 341          */
 342
 343         if ((addr_type & IPV6_ADDR_MULTICAST || skb->pkt_type != PACKET_HOST)) {
 344                 if (type != ICMPV6_PKT_TOOBIG &&
 345                     !(type == ICMPV6_PARAMPROB &&
 346                       code == ICMPV6_UNK_OPTION &&
 347                       (opt_unrec(skb, info))))
 348                         return;
 349
 350                 saddr = NULL;
 351         }
 352
 353         addr_type = ipv6_addr_type(&hdr->saddr);
 354
 355         /*
 356          *      Source addr check
 357          */
 358
 359         if (addr_type & IPV6_ADDR_LINKLOCAL)
 360                 iif = skb->dev->ifindex;
 361
 362         /*
 363          *      Must not send error if the source does not uniquely
 364          *      identify a single node (RFC2463 Section 2.4).
 365          *      We check unspecified / multicast addresses here,
 366          *      and anycast addresses will be checked later.
 367          */
 368         if ((addr_type == IPV6_ADDR_ANY) || (addr_type & IPV6_ADDR_MULTICAST)) {
 369                 LIMIT_NETDEBUG(KERN_DEBUG "icmpv6_send: addr_any/mcast source\n");
 370                 return;
 371         }
 372
 373         /*
 374          *      Never answer to a ICMP packet.
 375          */
 376         if (is_ineligible(skb)) {
 377                 LIMIT_NETDEBUG(KERN_DEBUG "icmpv6_send: no reply to icmp error\n");
 378                 return;
 379         }
 380
 381         mip6_addr_swap(skb);
 382
 383         memset(&fl, 0, sizeof(fl));
 384         fl.proto = IPPROTO_ICMPV6;
 385         ipv6_addr_copy(&fl.fl6_dst, &hdr->saddr);
 386         if (saddr)
 387                 ipv6_addr_copy(&fl.fl6_src, saddr);
 388         fl.oif = iif;
 389         fl.fl_icmp_type = type;
 390         fl.fl_icmp_code = code;
 391         security_skb_classify_flow(skb, &fl);
 392
 393         sk = icmpv6_xmit_lock(net);
 394         if (sk == NULL)
 395                 return;
 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(net, &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 relookup_failed;
 440
 441         if (ip6_dst_lookup(sk, &dst2, &fl2))
 442                 goto relookup_failed;
 443
 444         err = xfrm_lookup(net, &dst2, &fl2, sk, XFRM_LOOKUP_ICMP);
 445         switch (err) {
 446         case 0:
 447                 dst_release(dst);
 448                 dst = dst2;
 449                 break;
 450         case -EPERM:
 451                 goto out_dst_release;
 452         default:
 453 relookup_failed:
 454                 if (!dst)
 455                         goto out;
 456                 break;
 457         }
 458
 459 route_done:
 460         if (ipv6_addr_is_multicast(&fl.fl6_dst))
 461                 hlimit = np->mcast_hops;
 462         else
 463                 hlimit = np->hop_limit;
 464         if (hlimit < 0)
 465                 hlimit = ip6_dst_hoplimit(dst);
 466
 467         msg.skb = skb;
 468         msg.offset = skb_network_offset(skb);
 469         msg.type = type;
 470
 471         len = skb->len - msg.offset;
 472         len = min_t(unsigned int, len, IPV6_MIN_MTU - sizeof(struct ipv6hdr) -sizeof(struct icmp6hdr));
 473         if (len < 0) {
 474                 LIMIT_NETDEBUG(KERN_DEBUG "icmp: len problem\n");
 475                 goto out_dst_release;
 476         }
 477
 478         idev = in6_dev_get(skb->dev);
 479
 480         err = ip6_append_data(sk, icmpv6_getfrag, &msg,
 481                               len + sizeof(struct icmp6hdr),
 482                               sizeof(struct icmp6hdr), hlimit,
 483                               np->tclass, NULL, &fl, (struct rt6_info*)dst,
 484                               MSG_DONTWAIT);
 485         if (err) {
 486                 ip6_flush_pending_frames(sk);
 487                 goto out_put;
 488         }
 489         err = icmpv6_push_pending_frames(sk, &fl, &tmp_hdr, len + sizeof(struct icmp6hdr));
 490
 491 out_put:
 492         if (likely(idev != NULL))
 493                 in6_dev_put(idev);
 494 out_dst_release:
 495         dst_release(dst);
 496 out:
 497         icmpv6_xmit_unlock(sk);
 498 }
 499
 500 EXPORT_SYMBOL(icmpv6_send);
 501
 502 static void icmpv6_echo_reply(struct sk_buff *skb)
 503 {
 504         struct net *net = dev_net(skb->dev);
 505         struct sock *sk;
 506         struct inet6_dev *idev;
 507         struct ipv6_pinfo *np;
 508         struct in6_addr *saddr = NULL;
 509         struct icmp6hdr *icmph = icmp6_hdr(skb);
 510         struct icmp6hdr tmp_hdr;
 511         struct flowi fl;
 512         struct icmpv6_msg msg;
 513         struct dst_entry *dst;
 514         int err = 0;
 515         int hlimit;
 516
 517         saddr = &ipv6_hdr(skb)->daddr;
 518
 519         if (!ipv6_unicast_destination(skb))
 520                 saddr = NULL;
 521
 522         memcpy(&tmp_hdr, icmph, sizeof(tmp_hdr));
 523         tmp_hdr.icmp6_type = ICMPV6_ECHO_REPLY;
 524
 525         memset(&fl, 0, sizeof(fl));
 526         fl.proto = IPPROTO_ICMPV6;
 527         ipv6_addr_copy(&fl.fl6_dst, &ipv6_hdr(skb)->saddr);
 528         if (saddr)
 529                 ipv6_addr_copy(&fl.fl6_src, saddr);
 530         fl.oif = skb->dev->ifindex;
 531         fl.fl_icmp_type = ICMPV6_ECHO_REPLY;
 532         security_skb_classify_flow(skb, &fl);
 533
 534         sk = icmpv6_xmit_lock(net);
 535         if (sk == NULL)
 536                 return;
 537         np = inet6_sk(sk);
 538
 539         if (!fl.oif && ipv6_addr_is_multicast(&fl.fl6_dst))
 540                 fl.oif = np->mcast_oif;
 541
 542         err = ip6_dst_lookup(sk, &dst, &fl);
 543         if (err)
 544                 goto out;
 545         if ((err = xfrm_lookup(net, &dst, &fl, sk, 0)) < 0)
 546                 goto out;
 547
 548         if (ipv6_addr_is_multicast(&fl.fl6_dst))
 549                 hlimit = np->mcast_hops;
 550         else
 551                 hlimit = np->hop_limit;
 552         if (hlimit < 0)
 553                 hlimit = ip6_dst_hoplimit(dst);
 554
 555         idev = in6_dev_get(skb->dev);
 556
 557         msg.skb = skb;
 558         msg.offset = 0;
 559         msg.type = ICMPV6_ECHO_REPLY;
 560
 561         err = ip6_append_data(sk, icmpv6_getfrag, &msg, skb->len + sizeof(struct icmp6hdr),
 562                                 sizeof(struct icmp6hdr), hlimit, np->tclass, NULL, &fl,
 563                                 (struct rt6_info*)dst, MSG_DONTWAIT);
 564
 565         if (err) {
 566                 ip6_flush_pending_frames(sk);
 567                 goto out_put;
 568         }
 569         err = icmpv6_push_pending_frames(sk, &fl, &tmp_hdr, skb->len + sizeof(struct icmp6hdr));
 570
 571 out_put:
 572         if (likely(idev != NULL))
 573                 in6_dev_put(idev);
 574         dst_release(dst);
 575 out:
 576         icmpv6_xmit_unlock(sk);
 577 }
 578
 579 static void icmpv6_notify(struct sk_buff *skb, u8 type, u8 code, __be32 info)
 580 {
 581         const struct inet6_protocol *ipprot;
 582         int inner_offset;
 583         int hash;
 584         u8 nexthdr;
 585
 586         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
 587                 return;
 588
 589         nexthdr = ((struct ipv6hdr *)skb->data)->nexthdr;
 590         if (ipv6_ext_hdr(nexthdr)) {
 591                 /* now skip over extension headers */
 592                 inner_offset = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &nexthdr);
 593                 if (inner_offset<0)
 594                         return;
 595         } else {
 596                 inner_offset = sizeof(struct ipv6hdr);
 597         }
 598
 599         /* Checkin header including 8 bytes of inner protocol header. */
 600         if (!pskb_may_pull(skb, inner_offset+8))
 601                 return;
 602
 603         /* BUGGG_FUTURE: we should try to parse exthdrs in this packet.
 604            Without this we will not able f.e. to make source routed
 605            pmtu discovery.
 606            Corresponding argument (opt) to notifiers is already added.
 607            --ANK (980726)
 608          */
 609
 610         hash = nexthdr & (MAX_INET_PROTOS - 1);
 611
 612         rcu_read_lock();
 613         ipprot = rcu_dereference(inet6_protos[hash]);
 614         if (ipprot && ipprot->err_handler)
 615                 ipprot->err_handler(skb, NULL, type, code, inner_offset, info);
 616         rcu_read_unlock();
 617
 618         raw6_icmp_error(skb, nexthdr, type, code, inner_offset, info);
 619 }
 620
 621 /*
 622  *      Handle icmp messages
 623  */
 624
 625 static int icmpv6_rcv(struct sk_buff *skb)
 626 {
 627         struct net_device *dev = skb->dev;
 628         struct inet6_dev *idev = __in6_dev_get(dev);
 629         struct in6_addr *saddr, *daddr;
 630         struct ipv6hdr *orig_hdr;
 631         struct icmp6hdr *hdr;
 632         u8 type;
 633
 634         if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
 635                 struct sec_path *sp = skb_sec_path(skb);
 636                 int nh;
 637
 638                 if (!(sp && sp->xvec[sp->len - 1]->props.flags &
 639                                  XFRM_STATE_ICMP))
 640                         goto drop_no_count;
 641
 642                 if (!pskb_may_pull(skb, sizeof(*hdr) + sizeof(*orig_hdr)))
 643                         goto drop_no_count;
 644
 645                 nh = skb_network_offset(skb);
 646                 skb_set_network_header(skb, sizeof(*hdr));
 647
 648                 if (!xfrm6_policy_check_reverse(NULL, XFRM_POLICY_IN, skb))
 649                         goto drop_no_count;
 650
 651                 skb_set_network_header(skb, nh);
 652         }
 653
 654         ICMP6_INC_STATS_BH(dev_net(dev), idev, ICMP6_MIB_INMSGS);
 655
 656         saddr = &ipv6_hdr(skb)->saddr;
 657         daddr = &ipv6_hdr(skb)->daddr;
 658
 659         /* Perform checksum. */
 660         switch (skb->ip_summed) {
 661         case CHECKSUM_COMPLETE:
 662                 if (!csum_ipv6_magic(saddr, daddr, skb->len, IPPROTO_ICMPV6,
 663                                      skb->csum))
 664                         break;
 665                 /* fall through */
 666         case CHECKSUM_NONE:
 667                 skb->csum = ~csum_unfold(csum_ipv6_magic(saddr, daddr, skb->len,
 668                                              IPPROTO_ICMPV6, 0));
 669                 if (__skb_checksum_complete(skb)) {
 670                         LIMIT_NETDEBUG(KERN_DEBUG "ICMPv6 checksum failed [%pI6 > %pI6]\n",
 671                                        saddr, daddr);
 672                         goto discard_it;
 673                 }
 674         }
 675
 676         if (!pskb_pull(skb, sizeof(*hdr)))
 677                 goto discard_it;
 678
 679         hdr = icmp6_hdr(skb);
 680
 681         type = hdr->icmp6_type;
 682
 683         ICMP6MSGIN_INC_STATS_BH(dev_net(dev), idev, type);
 684
 685         switch (type) {
 686         case ICMPV6_ECHO_REQUEST:
 687                 icmpv6_echo_reply(skb);
 688                 break;
 689
 690         case ICMPV6_ECHO_REPLY:
 691                 /* we couldn't care less */
 692                 break;
 693
 694         case ICMPV6_PKT_TOOBIG:
 695                 /* BUGGG_FUTURE: if packet contains rthdr, we cannot update
 696                    standard destination cache. Seems, only "advanced"
 697                    destination cache will allow to solve this problem
 698                    --ANK (980726)
 699                  */
 700                 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
 701                         goto discard_it;
 702                 hdr = icmp6_hdr(skb);
 703                 orig_hdr = (struct ipv6hdr *) (hdr + 1);
 704                 rt6_pmtu_discovery(&orig_hdr->daddr, &orig_hdr->saddr, dev,
 705                                    ntohl(hdr->icmp6_mtu));
 706
 707                 /*
 708                  *      Drop through to notify
 709                  */
 710
 711         case ICMPV6_DEST_UNREACH:
 712         case ICMPV6_TIME_EXCEED:
 713         case ICMPV6_PARAMPROB:
 714                 icmpv6_notify(skb, type, hdr->icmp6_code, hdr->icmp6_mtu);
 715                 break;
 716
 717         case NDISC_ROUTER_SOLICITATION:
 718         case NDISC_ROUTER_ADVERTISEMENT:
 719         case NDISC_NEIGHBOUR_SOLICITATION:
 720         case NDISC_NEIGHBOUR_ADVERTISEMENT:
 721         case NDISC_REDIRECT:
 722                 ndisc_rcv(skb);
 723                 break;
 724
 725         case ICMPV6_MGM_QUERY:
 726                 igmp6_event_query(skb);
 727                 break;
 728
 729         case ICMPV6_MGM_REPORT:
 730                 igmp6_event_report(skb);
 731                 break;
 732
 733         case ICMPV6_MGM_REDUCTION:
 734         case ICMPV6_NI_QUERY:
 735         case ICMPV6_NI_REPLY:
 736         case ICMPV6_MLD2_REPORT:
 737         case ICMPV6_DHAAD_REQUEST:
 738         case ICMPV6_DHAAD_REPLY:
 739         case ICMPV6_MOBILE_PREFIX_SOL:
 740         case ICMPV6_MOBILE_PREFIX_ADV:
 741                 break;
 742
 743         default:
 744                 LIMIT_NETDEBUG(KERN_DEBUG "icmpv6: msg of unknown type\n");
 745
 746                 /* informational */
 747                 if (type & ICMPV6_INFOMSG_MASK)
 748                         break;
 749
 750                 /*
 751                  * error of unknown type.
 752                  * must pass to upper level
 753                  */
 754
 755                 icmpv6_notify(skb, type, hdr->icmp6_code, hdr->icmp6_mtu);
 756         }
 757
 758         kfree_skb(skb);
 759         return 0;
 760
 761 discard_it:
 762         ICMP6_INC_STATS_BH(dev_net(dev), idev, ICMP6_MIB_INERRORS);
 763 drop_no_count:
 764         kfree_skb(skb);
 765         return 0;
 766 }
 767
 768 void icmpv6_flow_init(struct sock *sk, struct flowi *fl,
 769                       u8 type,
 770                       const struct in6_addr *saddr,
 771                       const struct in6_addr *daddr,
 772                       int oif)
 773 {
 774         memset(fl, 0, sizeof(*fl));
 775         ipv6_addr_copy(&fl->fl6_src, saddr);
 776         ipv6_addr_copy(&fl->fl6_dst, daddr);
 777         fl->proto               = IPPROTO_ICMPV6;
 778         fl->fl_icmp_type        = type;
 779         fl->fl_icmp_code        = 0;
 780         fl->oif                 = oif;
 781         security_sk_classify_flow(sk, fl);
 782 }
 783
 784 /*
 785  * Special lock-class for __icmpv6_sk:
 786  */
 787 static struct lock_class_key icmpv6_socket_sk_dst_lock_key;
 788
 789 static int __net_init icmpv6_sk_init(struct net *net)
 790 {
 791         struct sock *sk;
 792         int err, i, j;
 793
 794         net->ipv6.icmp_sk =
 795                 kzalloc(nr_cpu_ids * sizeof(struct sock *), GFP_KERNEL);
 796         if (net->ipv6.icmp_sk == NULL)
 797                 return -ENOMEM;
 798
 799         for_each_possible_cpu(i) {
 800                 err = inet_ctl_sock_create(&sk, PF_INET6,
 801                                            SOCK_RAW, IPPROTO_ICMPV6, net);
 802                 if (err < 0) {
 803                         printk(KERN_ERR
 804                                "Failed to initialize the ICMP6 control socket "
 805                                "(err %d).\n",
 806                                err);
 807                         goto fail;
 808                 }
 809
 810                 net->ipv6.icmp_sk[i] = sk;
 811
 812                 /*
 813                  * Split off their lock-class, because sk->sk_dst_lock
 814                  * gets used from softirqs, which is safe for
 815                  * __icmpv6_sk (because those never get directly used
 816                  * via userspace syscalls), but unsafe for normal sockets.
 817                  */
 818                 lockdep_set_class(&sk->sk_dst_lock,
 819                                   &icmpv6_socket_sk_dst_lock_key);
 820
 821                 /* Enough space for 2 64K ICMP packets, including
 822                  * sk_buff struct overhead.
 823                  */
 824                 sk->sk_sndbuf =
 825                         (2 * ((64 * 1024) + sizeof(struct sk_buff)));
 826         }
 827         return 0;
 828
 829  fail:
 830         for (j = 0; j < i; j++)
 831                 inet_ctl_sock_destroy(net->ipv6.icmp_sk[j]);
 832         kfree(net->ipv6.icmp_sk);
 833         return err;
 834 }
 835
 836 static void __net_exit icmpv6_sk_exit(struct net *net)
 837 {
 838         int i;
 839
 840         for_each_possible_cpu(i) {
 841                 inet_ctl_sock_destroy(net->ipv6.icmp_sk[i]);
 842         }
 843         kfree(net->ipv6.icmp_sk);
 844 }
 845
 846 static struct pernet_operations icmpv6_sk_ops = {
 847        .init = icmpv6_sk_init,
 848        .exit = icmpv6_sk_exit,
 849 };
 850
 851 int __init icmpv6_init(void)
 852 {
 853         int err;
 854
 855         err = register_pernet_subsys(&icmpv6_sk_ops);
 856         if (err < 0)
 857                 return err;
 858
 859         err = -EAGAIN;
 860         if (inet6_add_protocol(&icmpv6_protocol, IPPROTO_ICMPV6) < 0)
 861                 goto fail;
 862         return 0;
 863
 864 fail:
 865         printk(KERN_ERR "Failed to register ICMP6 protocol\n");
 866         unregister_pernet_subsys(&icmpv6_sk_ops);
 867         return err;
 868 }
 869
 870 void icmpv6_cleanup(void)
 871 {
 872         unregister_pernet_subsys(&icmpv6_sk_ops);
 873         inet6_del_protocol(&icmpv6_protocol, IPPROTO_ICMPV6);
 874 }
 875
 876
 877 static const struct icmp6_err {
 878         int err;
 879         int fatal;
 880 } tab_unreach[] = {
 881         {       /* NOROUTE */
 882                 .err    = ENETUNREACH,
 883                 .fatal  = 0,
 884         },
 885         {       /* ADM_PROHIBITED */
 886                 .err    = EACCES,
 887                 .fatal  = 1,
 888         },
 889         {       /* Was NOT_NEIGHBOUR, now reserved */
 890                 .err    = EHOSTUNREACH,
 891                 .fatal  = 0,
 892         },
 893         {       /* ADDR_UNREACH */
 894                 .err    = EHOSTUNREACH,
 895                 .fatal  = 0,
 896         },
 897         {       /* PORT_UNREACH */
 898                 .err    = ECONNREFUSED,
 899                 .fatal  = 1,
 900         },
 901 };
 902
 903 int icmpv6_err_convert(u8 type, u8 code, int *err)
 904 {
 905         int fatal = 0;
 906
 907         *err = EPROTO;
 908
 909         switch (type) {
 910         case ICMPV6_DEST_UNREACH:
 911                 fatal = 1;
 912                 if (code <= ICMPV6_PORT_UNREACH) {
 913                         *err  = tab_unreach[code].err;
 914                         fatal = tab_unreach[code].fatal;
 915                 }
 916                 break;
 917
 918         case ICMPV6_PKT_TOOBIG:
 919                 *err = EMSGSIZE;
 920                 break;
 921
 922         case ICMPV6_PARAMPROB:
 923                 *err = EPROTO;
 924                 fatal = 1;
 925                 break;
 926
 927         case ICMPV6_TIME_EXCEED:
 928                 *err = EHOSTUNREACH;
 929                 break;
 930         }
 931
 932         return fatal;
 933 }
 934
 935 EXPORT_SYMBOL(icmpv6_err_convert);
 936
 937 #ifdef CONFIG_SYSCTL
 938 ctl_table ipv6_icmp_table_template[] = {
 939         {
 940                 .procname       = "ratelimit",
 941                 .data           = &init_net.ipv6.sysctl.icmpv6_time,
 942                 .maxlen         = sizeof(int),
 943                 .mode           = 0644,
 944                 .proc_handler   = proc_dointvec_ms_jiffies,
 945         },
 946         { },
 947 };
 948
 949 struct ctl_table * __net_init ipv6_icmp_sysctl_init(struct net *net)
 950 {
 951         struct ctl_table *table;
 952
 953         table = kmemdup(ipv6_icmp_table_template,
 954                         sizeof(ipv6_icmp_table_template),
 955                         GFP_KERNEL);
 956
 957         if (table)
 958                 table[0].data = &net->ipv6.sysctl.icmpv6_time;
 959
 960         return table;
 961 }
 962 #endif
 963