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
  44 #ifdef CONFIG_SYSCTL
  45 #include <linux/sysctl.h>
  46 #endif
  47
  48 #include <linux/inet.h>
  49 #include <linux/netdevice.h>
  50 #include <linux/icmpv6.h>
  51
  52 #include <net/ip.h>
  53 #include <net/sock.h>
  54
  55 #include <net/ipv6.h>
  56 #include <net/ip6_checksum.h>
  57 #include <net/protocol.h>
  58 #include <net/raw.h>
  59 #include <net/rawv6.h>
  60 #include <net/transp_v6.h>
  61 #include <net/ip6_route.h>
  62 #include <net/addrconf.h>
  63 #include <net/icmp.h>
  64 #include <net/xfrm.h>
  65 #include <net/inet_common.h>
  66
  67 #include <asm/uaccess.h>
  68 #include <asm/system.h>
  69
  70 DEFINE_SNMP_STAT(struct icmpv6_mib, icmpv6_statistics) __read_mostly;
  71 EXPORT_SYMBOL(icmpv6_statistics);
  72 DEFINE_SNMP_STAT(struct icmpv6msg_mib, icmpv6msg_statistics) __read_mostly;
  73 EXPORT_SYMBOL(icmpv6msg_statistics);
  74
  75 /*
  76  *      The ICMP socket(s). This is the most convenient way to flow control
  77  *      our ICMP output as well as maintain a clean interface throughout
  78  *      all layers. All Socketless IP sends will soon be gone.
  79  *
  80  *      On SMP we have one ICMP socket per-cpu.
  81  */
  82 static inline struct sock *icmpv6_sk(struct net *net)
  83 {
  84         return net->ipv6.icmp_sk[smp_processor_id()];
  85 }
  86
  87 static int icmpv6_rcv(struct sk_buff *skb);
  88
  89 static struct inet6_protocol icmpv6_protocol = {
  90         .handler        =       icmpv6_rcv,
  91         .flags          =       INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
  92 };
  93
  94 static __inline__ struct sock *icmpv6_xmit_lock(struct net *net)
  95 {
  96         struct sock *sk;
  97
  98         local_bh_disable();
  99
 100         sk = icmpv6_sk(net);
 101         if (unlikely(!spin_trylock(&sk->sk_lock.slock))) {
 102                 /* This can happen if the output path (f.e. SIT or
 103                  * ip6ip6 tunnel) signals dst_link_failure() for an
 104                  * outgoing ICMP6 packet.
 105                  */
 106                 local_bh_enable();
 107                 return NULL;
 108         }
 109         return sk;
 110 }
 111
 112 static __inline__ void icmpv6_xmit_unlock(struct sock *sk)
 113 {
 114         spin_unlock_bh(&sk->sk_lock.slock);
 115 }
 116
 117 /*
 118  * Slightly more convenient version of icmpv6_send.
 119  */
 120 void icmpv6_param_prob(struct sk_buff *skb, int code, int pos)
 121 {
 122         icmpv6_send(skb, ICMPV6_PARAMPROB, code, pos, skb->dev);
 123         kfree_skb(skb);
 124 }
 125
 126 /*
 127  * Figure out, may we reply to this packet with icmp error.
 128  *
 129  * We do not reply, if:
 130  *      - it was icmp error message.
 131  *      - it is truncated, so that it is known, that protocol is ICMPV6
 132  *        (i.e. in the middle of some exthdr)
 133  *
 134  *      --ANK (980726)
 135  */
 136
 137 static int is_ineligible(struct sk_buff *skb)
 138 {
 139         int ptr = (u8 *)(ipv6_hdr(skb) + 1) - skb->data;
 140         int len = skb->len - ptr;
 141         __u8 nexthdr = ipv6_hdr(skb)->nexthdr;
 142
 143         if (len < 0)
 144                 return 1;
 145
 146         ptr = ipv6_skip_exthdr(skb, ptr, &nexthdr);
 147         if (ptr < 0)
 148                 return 0;
 149         if (nexthdr == IPPROTO_ICMPV6) {
 150                 u8 _type, *tp;
 151                 tp = skb_header_pointer(skb,
 152                         ptr+offsetof(struct icmp6hdr, icmp6_type),
 153                         sizeof(_type), &_type);
 154                 if (tp == NULL ||
 155                     !(*tp & ICMPV6_INFOMSG_MASK))
 156                         return 1;
 157         }
 158         return 0;
 159 }
 160
 161 /*
 162  * Check the ICMP output rate limit
 163  */
 164 static inline int icmpv6_xrlim_allow(struct sock *sk, int type,
 165                                      struct flowi *fl)
 166 {
 167         struct dst_entry *dst;
 168         struct net *net = sock_net(sk);
 169         int res = 0;
 170
 171         /* Informational messages are not limited. */
 172         if (type & ICMPV6_INFOMSG_MASK)
 173                 return 1;
 174
 175         /* Do not limit pmtu discovery, it would break it. */
 176         if (type == ICMPV6_PKT_TOOBIG)
 177                 return 1;
 178
 179         /*
 180          * Look up the output route.
 181          * XXX: perhaps the expire for routing entries cloned by
 182          * this lookup should be more aggressive (not longer than timeout).
 183          */
 184         dst = ip6_route_output(net, sk, fl);
 185         if (dst->error) {
 186                 IP6_INC_STATS(net, ip6_dst_idev(dst),
 187                               IPSTATS_MIB_OUTNOROUTES);
 188         } else if (dst->dev && (dst->dev->flags&IFF_LOOPBACK)) {
 189                 res = 1;
 190         } else {
 191                 struct rt6_info *rt = (struct rt6_info *)dst;
 192                 int tmo = net->ipv6.sysctl.icmpv6_time;
 193
 194                 /* Give more bandwidth to wider prefixes. */
 195                 if (rt->rt6i_dst.plen < 128)
 196                         tmo >>= ((128 - rt->rt6i_dst.plen)>>5);
 197
 198                 res = xrlim_allow(dst, tmo);
 199         }
 200         dst_release(dst);
 201         return res;
 202 }
 203
 204 /*
 205  *      an inline helper for the "simple" if statement below
 206  *      checks if parameter problem report is caused by an
 207  *      unrecognized IPv6 option that has the Option Type
 208  *      highest-order two bits set to 10
 209  */
 210
 211 static __inline__ int opt_unrec(struct sk_buff *skb, __u32 offset)
 212 {
 213         u8 _optval, *op;
 214
 215         offset += skb_network_offset(skb);
 216         op = skb_header_pointer(skb, offset, sizeof(_optval), &_optval);
 217         if (op == NULL)
 218                 return 1;
 219         return (*op & 0xC0) == 0x80;
 220 }
 221
 222 static int icmpv6_push_pending_frames(struct sock *sk, struct flowi *fl, struct icmp6hdr *thdr, int len)
 223 {
 224         struct sk_buff *skb;
 225         struct icmp6hdr *icmp6h;
 226         int err = 0;
 227
 228         if ((skb = skb_peek(&sk->sk_write_queue)) == NULL)
 229                 goto out;
 230
 231         icmp6h = icmp6_hdr(skb);
 232         memcpy(icmp6h, thdr, sizeof(struct icmp6hdr));
 233         icmp6h->icmp6_cksum = 0;
 234
 235         if (skb_queue_len(&sk->sk_write_queue) == 1) {
 236                 skb->csum = csum_partial(icmp6h,
 237                                         sizeof(struct icmp6hdr), skb->csum);
 238                 icmp6h->icmp6_cksum = csum_ipv6_magic(&fl->fl6_src,
 239                                                       &fl->fl6_dst,
 240                                                       len, fl->proto,
 241                                                       skb->csum);
 242         } else {
 243                 __wsum tmp_csum = 0;
 244
 245                 skb_queue_walk(&sk->sk_write_queue, skb) {
 246                         tmp_csum = csum_add(tmp_csum, skb->csum);
 247                 }
 248
 249                 tmp_csum = csum_partial(icmp6h,
 250                                         sizeof(struct icmp6hdr), tmp_csum);
 251                 icmp6h->icmp6_cksum = csum_ipv6_magic(&fl->fl6_src,
 252                                                       &fl->fl6_dst,
 253                                                       len, fl->proto,
 254                                                       tmp_csum);
 255         }
 256         ip6_push_pending_frames(sk);
 257 out:
 258         return err;
 259 }
 260
 261 struct icmpv6_msg {
 262         struct sk_buff  *skb;
 263         int             offset;
 264         uint8_t         type;
 265 };
 266
 267 static int icmpv6_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb)
 268 {
 269         struct icmpv6_msg *msg = (struct icmpv6_msg *) from;
 270         struct sk_buff *org_skb = msg->skb;
 271         __wsum csum = 0;
 272
 273         csum = skb_copy_and_csum_bits(org_skb, msg->offset + offset,
 274                                       to, len, csum);
 275         skb->csum = csum_block_add(skb->csum, csum, odd);
 276         if (!(msg->type & ICMPV6_INFOMSG_MASK))
 277                 nf_ct_attach(skb, org_skb);
 278         return 0;
 279 }
 280
 281 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
 282 static void mip6_addr_swap(struct sk_buff *skb)
 283 {
 284         struct ipv6hdr *iph = ipv6_hdr(skb);
 285         struct inet6_skb_parm *opt = IP6CB(skb);
 286         struct ipv6_destopt_hao *hao;
 287         struct in6_addr tmp;
 288         int off;
 289
 290         if (opt->dsthao) {
 291                 off = ipv6_find_tlv(skb, opt->dsthao, IPV6_TLV_HAO);
 292                 if (likely(off >= 0)) {
 293                         hao = (struct ipv6_destopt_hao *)
 294                                         (skb_network_header(skb) + off);
 295                         ipv6_addr_copy(&tmp, &iph->saddr);
 296                         ipv6_addr_copy(&iph->saddr, &hao->addr);
 297                         ipv6_addr_copy(&hao->addr, &tmp);
 298                 }
 299         }
 300 }
 301 #else
 302 static inline void mip6_addr_swap(struct sk_buff *skb) {}
 303 #endif
 304
 305 /*
 306  *      Send an ICMP message in response to a packet in error
 307  */
 308 void icmpv6_send(struct sk_buff *skb, int type, int code, __u32 info,
 309                  struct net_device *dev)
 310 {
 311         struct net *net = dev_net(skb->dev);
 312         struct inet6_dev *idev = NULL;
 313         struct ipv6hdr *hdr = ipv6_hdr(skb);
 314         struct sock *sk;
 315         struct ipv6_pinfo *np;
 316         struct in6_addr *saddr = NULL;
 317         struct dst_entry *dst;
 318         struct dst_entry *dst2;
 319         struct icmp6hdr tmp_hdr;
 320         struct flowi fl;
 321         struct flowi fl2;
 322         struct icmpv6_msg msg;
 323         int iif = 0;
 324         int addr_type = 0;
 325         int len;
 326         int hlimit, tclass;
 327         int err = 0;
 328
 329         if ((u8 *)hdr < skb->head ||
 330             (skb->network_header + sizeof(*hdr)) > skb->tail)
 331                 return;
 332
 333         /*
 334          *      Make sure we respect the rules
 335          *      i.e. RFC 1885 2.4(e)
 336          *      Rule (e.1) is enforced by not using icmpv6_send
 337          *      in any code that processes icmp errors.
 338          */
 339         addr_type = ipv6_addr_type(&hdr->daddr);
 340
 341         if (ipv6_chk_addr(net, &hdr->daddr, skb->dev, 0))
 342                 saddr = &hdr->daddr;
 343
 344         /*
 345          *      Dest addr check
 346          */
 347
 348         if ((addr_type & IPV6_ADDR_MULTICAST || skb->pkt_type != PACKET_HOST)) {
 349                 if (type != ICMPV6_PKT_TOOBIG &&
 350                     !(type == ICMPV6_PARAMPROB &&
 351                       code == ICMPV6_UNK_OPTION &&
 352                       (opt_unrec(skb, info))))
 353                         return;
 354
 355                 saddr = NULL;
 356         }
 357
 358         addr_type = ipv6_addr_type(&hdr->saddr);
 359
 360         /*
 361          *      Source addr check
 362          */
 363
 364         if (addr_type & IPV6_ADDR_LINKLOCAL)
 365                 iif = skb->dev->ifindex;
 366
 367         /*
 368          *      Must not send error if the source does not uniquely
 369          *      identify a single node (RFC2463 Section 2.4).
 370          *      We check unspecified / multicast addresses here,
 371          *      and anycast addresses will be checked later.
 372          */
 373         if ((addr_type == IPV6_ADDR_ANY) || (addr_type & IPV6_ADDR_MULTICAST)) {
 374                 LIMIT_NETDEBUG(KERN_DEBUG "icmpv6_send: addr_any/mcast source\n");
 375                 return;
 376         }
 377
 378         /*
 379          *      Never answer to a ICMP packet.
 380          */
 381         if (is_ineligible(skb)) {
 382                 LIMIT_NETDEBUG(KERN_DEBUG "icmpv6_send: no reply to icmp error\n");
 383                 return;
 384         }
 385
 386         mip6_addr_swap(skb);
 387
 388         memset(&fl, 0, sizeof(fl));
 389         fl.proto = IPPROTO_ICMPV6;
 390         ipv6_addr_copy(&fl.fl6_dst, &hdr->saddr);
 391         if (saddr)
 392                 ipv6_addr_copy(&fl.fl6_src, saddr);
 393         fl.oif = iif;
 394         fl.fl_icmp_type = type;
 395         fl.fl_icmp_code = code;
 396         security_skb_classify_flow(skb, &fl);
 397
 398         sk = icmpv6_xmit_lock(net);
 399         if (sk == NULL)
 400                 return;
 401         np = inet6_sk(sk);
 402
 403         if (!icmpv6_xrlim_allow(sk, type, &fl))
 404                 goto out;
 405
 406         tmp_hdr.icmp6_type = type;
 407         tmp_hdr.icmp6_code = code;
 408         tmp_hdr.icmp6_cksum = 0;
 409         tmp_hdr.icmp6_pointer = htonl(info);
 410
 411         if (!fl.oif && ipv6_addr_is_multicast(&fl.fl6_dst))
 412                 fl.oif = np->mcast_oif;
 413
 414         err = ip6_dst_lookup(sk, &dst, &fl);
 415         if (err)
 416                 goto out;
 417
 418         /*
 419          * We won't send icmp if the destination is known
 420          * anycast.
 421          */
 422         if (((struct rt6_info *)dst)->rt6i_flags & RTF_ANYCAST) {
 423                 LIMIT_NETDEBUG(KERN_DEBUG "icmpv6_send: acast source\n");
 424                 goto out_dst_release;
 425         }
 426
 427         /* No need to clone since we're just using its address. */
 428         dst2 = dst;
 429
 430         err = xfrm_lookup(net, &dst, &fl, sk, 0);
 431         switch (err) {
 432         case 0:
 433                 if (dst != dst2)
 434                         goto route_done;
 435                 break;
 436         case -EPERM:
 437                 dst = NULL;
 438                 break;
 439         default:
 440                 goto out;
 441         }
 442
 443         if (xfrm_decode_session_reverse(skb, &fl2, AF_INET6))
 444                 goto relookup_failed;
 445
 446         if (ip6_dst_lookup(sk, &dst2, &fl))
 447                 goto relookup_failed;
 448
 449         err = xfrm_lookup(net, &dst2, &fl, sk, XFRM_LOOKUP_ICMP);
 450         switch (err) {
 451         case 0:
 452                 dst_release(dst);
 453                 dst = dst2;
 454                 break;
 455         case -EPERM:
 456                 goto out_dst_release;
 457         default:
 458 relookup_failed:
 459                 if (!dst)
 460                         goto out;
 461                 break;
 462         }
 463
 464 route_done:
 465         if (ipv6_addr_is_multicast(&fl.fl6_dst))
 466                 hlimit = np->mcast_hops;
 467         else
 468                 hlimit = np->hop_limit;
 469         if (hlimit < 0)
 470                 hlimit = ip6_dst_hoplimit(dst);
 471
 472         tclass = np->tclass;
 473         if (tclass < 0)
 474                 tclass = 0;
 475
 476         msg.skb = skb;
 477         msg.offset = skb_network_offset(skb);
 478         msg.type = type;
 479
 480         len = skb->len - msg.offset;
 481         len = min_t(unsigned int, len, IPV6_MIN_MTU - sizeof(struct ipv6hdr) -sizeof(struct icmp6hdr));
 482         if (len < 0) {
 483                 LIMIT_NETDEBUG(KERN_DEBUG "icmp: len problem\n");
 484                 goto out_dst_release;
 485         }
 486
 487         idev = in6_dev_get(skb->dev);
 488
 489         err = ip6_append_data(sk, icmpv6_getfrag, &msg,
 490                               len + sizeof(struct icmp6hdr),
 491                               sizeof(struct icmp6hdr),
 492                               hlimit, tclass, NULL, &fl, (struct rt6_info*)dst,
 493                               MSG_DONTWAIT);
 494         if (err) {
 495                 ip6_flush_pending_frames(sk);
 496                 goto out_put;
 497         }
 498         err = icmpv6_push_pending_frames(sk, &fl, &tmp_hdr, len + sizeof(struct icmp6hdr));
 499
 500 out_put:
 501         if (likely(idev != NULL))
 502                 in6_dev_put(idev);
 503 out_dst_release:
 504         dst_release(dst);
 505 out:
 506         icmpv6_xmit_unlock(sk);
 507 }
 508
 509 EXPORT_SYMBOL(icmpv6_send);
 510
 511 static void icmpv6_echo_reply(struct sk_buff *skb)
 512 {
 513         struct net *net = dev_net(skb->dev);
 514         struct sock *sk;
 515         struct inet6_dev *idev;
 516         struct ipv6_pinfo *np;
 517         struct in6_addr *saddr = NULL;
 518         struct icmp6hdr *icmph = icmp6_hdr(skb);
 519         struct icmp6hdr tmp_hdr;
 520         struct flowi fl;
 521         struct icmpv6_msg msg;
 522         struct dst_entry *dst;
 523         int err = 0;
 524         int hlimit;
 525         int tclass;
 526
 527         saddr = &ipv6_hdr(skb)->daddr;
 528
 529         if (!ipv6_unicast_destination(skb))
 530                 saddr = NULL;
 531
 532         memcpy(&tmp_hdr, icmph, sizeof(tmp_hdr));
 533         tmp_hdr.icmp6_type = ICMPV6_ECHO_REPLY;
 534
 535         memset(&fl, 0, sizeof(fl));
 536         fl.proto = IPPROTO_ICMPV6;
 537         ipv6_addr_copy(&fl.fl6_dst, &ipv6_hdr(skb)->saddr);
 538         if (saddr)
 539                 ipv6_addr_copy(&fl.fl6_src, saddr);
 540         fl.oif = skb->dev->ifindex;
 541         fl.fl_icmp_type = ICMPV6_ECHO_REPLY;
 542         security_skb_classify_flow(skb, &fl);
 543
 544         sk = icmpv6_xmit_lock(net);
 545         if (sk == NULL)
 546                 return;
 547         np = inet6_sk(sk);
 548
 549         if (!fl.oif && ipv6_addr_is_multicast(&fl.fl6_dst))
 550                 fl.oif = np->mcast_oif;
 551
 552         err = ip6_dst_lookup(sk, &dst, &fl);
 553         if (err)
 554                 goto out;
 555         if ((err = xfrm_lookup(net, &dst, &fl, sk, 0)) < 0)
 556                 goto out;
 557
 558         if (ipv6_addr_is_multicast(&fl.fl6_dst))
 559                 hlimit = np->mcast_hops;
 560         else
 561                 hlimit = np->hop_limit;
 562         if (hlimit < 0)
 563                 hlimit = ip6_dst_hoplimit(dst);
 564
 565         tclass = np->tclass;
 566         if (tclass < 0)
 567                 tclass = 0;
 568
 569         idev = in6_dev_get(skb->dev);
 570
 571         msg.skb = skb;
 572         msg.offset = 0;
 573         msg.type = ICMPV6_ECHO_REPLY;
 574
 575         err = ip6_append_data(sk, icmpv6_getfrag, &msg, skb->len + sizeof(struct icmp6hdr),
 576                                 sizeof(struct icmp6hdr), hlimit, tclass, NULL, &fl,
 577                                 (struct rt6_info*)dst, MSG_DONTWAIT);
 578
 579         if (err) {
 580                 ip6_flush_pending_frames(sk);
 581                 goto out_put;
 582         }
 583         err = icmpv6_push_pending_frames(sk, &fl, &tmp_hdr, skb->len + sizeof(struct icmp6hdr));
 584
 585 out_put:
 586         if (likely(idev != NULL))
 587                 in6_dev_put(idev);
 588         dst_release(dst);
 589 out:
 590         icmpv6_xmit_unlock(sk);
 591 }
 592
 593 static void icmpv6_notify(struct sk_buff *skb, int type, int code, __be32 info)
 594 {
 595         struct inet6_protocol *ipprot;
 596         int inner_offset;
 597         int hash;
 598         u8 nexthdr;
 599
 600         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
 601                 return;
 602
 603         nexthdr = ((struct ipv6hdr *)skb->data)->nexthdr;
 604         if (ipv6_ext_hdr(nexthdr)) {
 605                 /* now skip over extension headers */
 606                 inner_offset = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &nexthdr);
 607                 if (inner_offset<0)
 608                         return;
 609         } else {
 610                 inner_offset = sizeof(struct ipv6hdr);
 611         }
 612
 613         /* Checkin header including 8 bytes of inner protocol header. */
 614         if (!pskb_may_pull(skb, inner_offset+8))
 615                 return;
 616
 617         /* BUGGG_FUTURE: we should try to parse exthdrs in this packet.
 618            Without this we will not able f.e. to make source routed
 619            pmtu discovery.
 620            Corresponding argument (opt) to notifiers is already added.
 621            --ANK (980726)
 622          */
 623
 624         hash = nexthdr & (MAX_INET_PROTOS - 1);
 625
 626         rcu_read_lock();
 627         ipprot = rcu_dereference(inet6_protos[hash]);
 628         if (ipprot && ipprot->err_handler)
 629                 ipprot->err_handler(skb, NULL, type, code, inner_offset, info);
 630         rcu_read_unlock();
 631
 632         raw6_icmp_error(skb, nexthdr, type, code, inner_offset, info);
 633 }
 634
 635 /*
 636  *      Handle icmp messages
 637  */
 638
 639 static int icmpv6_rcv(struct sk_buff *skb)
 640 {
 641         struct net_device *dev = skb->dev;
 642         struct inet6_dev *idev = __in6_dev_get(dev);
 643         struct in6_addr *saddr, *daddr;
 644         struct ipv6hdr *orig_hdr;
 645         struct icmp6hdr *hdr;
 646         int type;
 647
 648         if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
 649                 struct sec_path *sp = skb_sec_path(skb);
 650                 int nh;
 651
 652                 if (!(sp && sp->xvec[sp->len - 1]->props.flags &
 653                                  XFRM_STATE_ICMP))
 654                         goto drop_no_count;
 655
 656                 if (!pskb_may_pull(skb, sizeof(*hdr) + sizeof(*orig_hdr)))
 657                         goto drop_no_count;
 658
 659                 nh = skb_network_offset(skb);
 660                 skb_set_network_header(skb, sizeof(*hdr));
 661
 662                 if (!xfrm6_policy_check_reverse(NULL, XFRM_POLICY_IN, skb))
 663                         goto drop_no_count;
 664
 665                 skb_set_network_header(skb, nh);
 666         }
 667
 668         ICMP6_INC_STATS_BH(dev_net(dev), idev, ICMP6_MIB_INMSGS);
 669
 670         saddr = &ipv6_hdr(skb)->saddr;
 671         daddr = &ipv6_hdr(skb)->daddr;
 672
 673         /* Perform checksum. */
 674         switch (skb->ip_summed) {
 675         case CHECKSUM_COMPLETE:
 676                 if (!csum_ipv6_magic(saddr, daddr, skb->len, IPPROTO_ICMPV6,
 677                                      skb->csum))
 678                         break;
 679                 /* fall through */
 680         case CHECKSUM_NONE:
 681                 skb->csum = ~csum_unfold(csum_ipv6_magic(saddr, daddr, skb->len,
 682                                              IPPROTO_ICMPV6, 0));
 683                 if (__skb_checksum_complete(skb)) {
 684                         LIMIT_NETDEBUG(KERN_DEBUG "ICMPv6 checksum failed [%pI6 > %pI6]\n",
 685                                        saddr, daddr);
 686                         goto discard_it;
 687                 }
 688         }
 689
 690         if (!pskb_pull(skb, sizeof(*hdr)))
 691                 goto discard_it;
 692
 693         hdr = icmp6_hdr(skb);
 694
 695         type = hdr->icmp6_type;
 696
 697         ICMP6MSGIN_INC_STATS_BH(dev_net(dev), idev, type);
 698
 699         switch (type) {
 700         case ICMPV6_ECHO_REQUEST:
 701                 icmpv6_echo_reply(skb);
 702                 break;
 703
 704         case ICMPV6_ECHO_REPLY:
 705                 /* we couldn't care less */
 706                 break;
 707
 708         case ICMPV6_PKT_TOOBIG:
 709                 /* BUGGG_FUTURE: if packet contains rthdr, we cannot update
 710                    standard destination cache. Seems, only "advanced"
 711                    destination cache will allow to solve this problem
 712                    --ANK (980726)
 713                  */
 714                 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
 715                         goto discard_it;
 716                 hdr = icmp6_hdr(skb);
 717                 orig_hdr = (struct ipv6hdr *) (hdr + 1);
 718                 rt6_pmtu_discovery(&orig_hdr->daddr, &orig_hdr->saddr, dev,
 719                                    ntohl(hdr->icmp6_mtu));
 720
 721                 /*
 722                  *      Drop through to notify
 723                  */
 724
 725         case ICMPV6_DEST_UNREACH:
 726         case ICMPV6_TIME_EXCEED:
 727         case ICMPV6_PARAMPROB:
 728                 icmpv6_notify(skb, type, hdr->icmp6_code, hdr->icmp6_mtu);
 729                 break;
 730
 731         case NDISC_ROUTER_SOLICITATION:
 732         case NDISC_ROUTER_ADVERTISEMENT:
 733         case NDISC_NEIGHBOUR_SOLICITATION:
 734         case NDISC_NEIGHBOUR_ADVERTISEMENT:
 735         case NDISC_REDIRECT:
 736                 ndisc_rcv(skb);
 737                 break;
 738
 739         case ICMPV6_MGM_QUERY:
 740                 igmp6_event_query(skb);
 741                 break;
 742
 743         case ICMPV6_MGM_REPORT:
 744                 igmp6_event_report(skb);
 745                 break;
 746
 747         case ICMPV6_MGM_REDUCTION:
 748         case ICMPV6_NI_QUERY:
 749         case ICMPV6_NI_REPLY:
 750         case ICMPV6_MLD2_REPORT:
 751         case ICMPV6_DHAAD_REQUEST:
 752         case ICMPV6_DHAAD_REPLY:
 753         case ICMPV6_MOBILE_PREFIX_SOL:
 754         case ICMPV6_MOBILE_PREFIX_ADV:
 755                 break;
 756
 757         default:
 758                 LIMIT_NETDEBUG(KERN_DEBUG "icmpv6: msg of unknown type\n");
 759
 760                 /* informational */
 761                 if (type & ICMPV6_INFOMSG_MASK)
 762                         break;
 763
 764                 /*
 765                  * error of unknown type.
 766                  * must pass to upper level
 767                  */
 768
 769                 icmpv6_notify(skb, type, hdr->icmp6_code, hdr->icmp6_mtu);
 770         }
 771
 772         kfree_skb(skb);
 773         return 0;
 774
 775 discard_it:
 776         ICMP6_INC_STATS_BH(dev_net(dev), idev, ICMP6_MIB_INERRORS);
 777 drop_no_count:
 778         kfree_skb(skb);
 779         return 0;
 780 }
 781
 782 void icmpv6_flow_init(struct sock *sk, struct flowi *fl,
 783                       u8 type,
 784                       const struct in6_addr *saddr,
 785                       const struct in6_addr *daddr,
 786                       int oif)
 787 {
 788         memset(fl, 0, sizeof(*fl));
 789         ipv6_addr_copy(&fl->fl6_src, saddr);
 790         ipv6_addr_copy(&fl->fl6_dst, daddr);
 791         fl->proto               = IPPROTO_ICMPV6;
 792         fl->fl_icmp_type        = type;
 793         fl->fl_icmp_code        = 0;
 794         fl->oif                 = oif;
 795         security_sk_classify_flow(sk, fl);
 796 }
 797
 798 /*
 799  * Special lock-class for __icmpv6_sk:
 800  */
 801 static struct lock_class_key icmpv6_socket_sk_dst_lock_key;
 802
 803 static int __net_init icmpv6_sk_init(struct net *net)
 804 {
 805         struct sock *sk;
 806         int err, i, j;
 807
 808         net->ipv6.icmp_sk =
 809                 kzalloc(nr_cpu_ids * sizeof(struct sock *), GFP_KERNEL);
 810         if (net->ipv6.icmp_sk == NULL)
 811                 return -ENOMEM;
 812
 813         for_each_possible_cpu(i) {
 814                 err = inet_ctl_sock_create(&sk, PF_INET6,
 815                                            SOCK_RAW, IPPROTO_ICMPV6, net);
 816                 if (err < 0) {
 817                         printk(KERN_ERR
 818                                "Failed to initialize the ICMP6 control socket "
 819                                "(err %d).\n",
 820                                err);
 821                         goto fail;
 822                 }
 823
 824                 net->ipv6.icmp_sk[i] = sk;
 825
 826                 /*
 827                  * Split off their lock-class, because sk->sk_dst_lock
 828                  * gets used from softirqs, which is safe for
 829                  * __icmpv6_sk (because those never get directly used
 830                  * via userspace syscalls), but unsafe for normal sockets.
 831                  */
 832                 lockdep_set_class(&sk->sk_dst_lock,
 833                                   &icmpv6_socket_sk_dst_lock_key);
 834
 835                 /* Enough space for 2 64K ICMP packets, including
 836                  * sk_buff struct overhead.
 837                  */
 838                 sk->sk_sndbuf =
 839                         (2 * ((64 * 1024) + sizeof(struct sk_buff)));
 840         }
 841         return 0;
 842
 843  fail:
 844         for (j = 0; j < i; j++)
 845                 inet_ctl_sock_destroy(net->ipv6.icmp_sk[j]);
 846         kfree(net->ipv6.icmp_sk);
 847         return err;
 848 }
 849
 850 static void __net_exit icmpv6_sk_exit(struct net *net)
 851 {
 852         int i;
 853
 854         for_each_possible_cpu(i) {
 855                 inet_ctl_sock_destroy(net->ipv6.icmp_sk[i]);
 856         }
 857         kfree(net->ipv6.icmp_sk);
 858 }
 859
 860 static struct pernet_operations icmpv6_sk_ops = {
 861        .init = icmpv6_sk_init,
 862        .exit = icmpv6_sk_exit,
 863 };
 864
 865 int __init icmpv6_init(void)
 866 {
 867         int err;
 868
 869         err = register_pernet_subsys(&icmpv6_sk_ops);
 870         if (err < 0)
 871                 return err;
 872
 873         err = -EAGAIN;
 874         if (inet6_add_protocol(&icmpv6_protocol, IPPROTO_ICMPV6) < 0)
 875                 goto fail;
 876         return 0;
 877
 878 fail:
 879         printk(KERN_ERR "Failed to register ICMP6 protocol\n");
 880         unregister_pernet_subsys(&icmpv6_sk_ops);
 881         return err;
 882 }
 883
 884 void icmpv6_cleanup(void)
 885 {
 886         unregister_pernet_subsys(&icmpv6_sk_ops);
 887         inet6_del_protocol(&icmpv6_protocol, IPPROTO_ICMPV6);
 888 }
 889
 890
 891 static const struct icmp6_err {
 892         int err;
 893         int fatal;
 894 } tab_unreach[] = {
 895         {       /* NOROUTE */
 896                 .err    = ENETUNREACH,
 897                 .fatal  = 0,
 898         },
 899         {       /* ADM_PROHIBITED */
 900                 .err    = EACCES,
 901                 .fatal  = 1,
 902         },
 903         {       /* Was NOT_NEIGHBOUR, now reserved */
 904                 .err    = EHOSTUNREACH,
 905                 .fatal  = 0,
 906         },
 907         {       /* ADDR_UNREACH */
 908                 .err    = EHOSTUNREACH,
 909                 .fatal  = 0,
 910         },
 911         {       /* PORT_UNREACH */
 912                 .err    = ECONNREFUSED,
 913                 .fatal  = 1,
 914         },
 915 };
 916
 917 int icmpv6_err_convert(int type, int code, int *err)
 918 {
 919         int fatal = 0;
 920
 921         *err = EPROTO;
 922
 923         switch (type) {
 924         case ICMPV6_DEST_UNREACH:
 925                 fatal = 1;
 926                 if (code <= ICMPV6_PORT_UNREACH) {
 927                         *err  = tab_unreach[code].err;
 928                         fatal = tab_unreach[code].fatal;
 929                 }
 930                 break;
 931
 932         case ICMPV6_PKT_TOOBIG:
 933                 *err = EMSGSIZE;
 934                 break;
 935
 936         case ICMPV6_PARAMPROB:
 937                 *err = EPROTO;
 938                 fatal = 1;
 939                 break;
 940
 941         case ICMPV6_TIME_EXCEED:
 942                 *err = EHOSTUNREACH;
 943                 break;
 944         }
 945
 946         return fatal;
 947 }
 948
 949 EXPORT_SYMBOL(icmpv6_err_convert);
 950
 951 #ifdef CONFIG_SYSCTL
 952 ctl_table ipv6_icmp_table_template[] = {
 953         {
 954                 .ctl_name       = NET_IPV6_ICMP_RATELIMIT,
 955                 .procname       = "ratelimit",
 956                 .data           = &init_net.ipv6.sysctl.icmpv6_time,
 957                 .maxlen         = sizeof(int),
 958                 .mode           = 0644,
 959                 .proc_handler   = proc_dointvec_ms_jiffies,
 960                 .strategy       = sysctl_ms_jiffies
 961         },
 962         { .ctl_name = 0 },
 963 };
 964
 965 struct ctl_table *ipv6_icmp_sysctl_init(struct net *net)
 966 {
 967         struct ctl_table *table;
 968
 969         table = kmemdup(ipv6_icmp_table_template,
 970                         sizeof(ipv6_icmp_table_template),
 971                         GFP_KERNEL);
 972
 973         if (table)
 974                 table[0].data = &net->ipv6.sysctl.icmpv6_time;
 975
 976         return table;
 977 }
 978 #endif
 979