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 bool icmpv6_xrlim_allow(struct sock *sk, u8 type,
 161                                       struct flowi6 *fl6)
 162 {
 163         struct dst_entry *dst;
 164         struct net *net = sock_net(sk);
 165         bool res = false;
 166
 167         /* Informational messages are not limited. */
 168         if (type & ICMPV6_INFOMSG_MASK)
 169                 return true;
 170
 171         /* Do not limit pmtu discovery, it would break it. */
 172         if (type == ICMPV6_PKT_TOOBIG)
 173                 return true;
 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, fl6);
 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 = true;
 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                 if (!rt->rt6i_peer)
 195                         rt6_bind_peer(rt, 1);
 196                 res = inet_peer_xrlim_allow(rt->rt6i_peer, tmo);
 197         }
 198         dst_release(dst);
 199         return res;
 200 }
 201
 202 /*
 203  *      an inline helper for the "simple" if statement below
 204  *      checks if parameter problem report is caused by an
 205  *      unrecognized IPv6 option that has the Option Type
 206  *      highest-order two bits set to 10
 207  */
 208
 209 static __inline__ int opt_unrec(struct sk_buff *skb, __u32 offset)
 210 {
 211         u8 _optval, *op;
 212
 213         offset += skb_network_offset(skb);
 214         op = skb_header_pointer(skb, offset, sizeof(_optval), &_optval);
 215         if (op == NULL)
 216                 return 1;
 217         return (*op & 0xC0) == 0x80;
 218 }
 219
 220 static int icmpv6_push_pending_frames(struct sock *sk, struct flowi6 *fl6, struct icmp6hdr *thdr, int len)
 221 {
 222         struct sk_buff *skb;
 223         struct icmp6hdr *icmp6h;
 224         int err = 0;
 225
 226         if ((skb = skb_peek(&sk->sk_write_queue)) == NULL)
 227                 goto out;
 228
 229         icmp6h = icmp6_hdr(skb);
 230         memcpy(icmp6h, thdr, sizeof(struct icmp6hdr));
 231         icmp6h->icmp6_cksum = 0;
 232
 233         if (skb_queue_len(&sk->sk_write_queue) == 1) {
 234                 skb->csum = csum_partial(icmp6h,
 235                                         sizeof(struct icmp6hdr), skb->csum);
 236                 icmp6h->icmp6_cksum = csum_ipv6_magic(&fl6->saddr,
 237                                                       &fl6->daddr,
 238                                                       len, fl6->flowi6_proto,
 239                                                       skb->csum);
 240         } else {
 241                 __wsum tmp_csum = 0;
 242
 243                 skb_queue_walk(&sk->sk_write_queue, skb) {
 244                         tmp_csum = csum_add(tmp_csum, skb->csum);
 245                 }
 246
 247                 tmp_csum = csum_partial(icmp6h,
 248                                         sizeof(struct icmp6hdr), tmp_csum);
 249                 icmp6h->icmp6_cksum = csum_ipv6_magic(&fl6->saddr,
 250                                                       &fl6->daddr,
 251                                                       len, fl6->flowi6_proto,
 252                                                       tmp_csum);
 253         }
 254         ip6_push_pending_frames(sk);
 255 out:
 256         return err;
 257 }
 258
 259 struct icmpv6_msg {
 260         struct sk_buff  *skb;
 261         int             offset;
 262         uint8_t         type;
 263 };
 264
 265 static int icmpv6_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb)
 266 {
 267         struct icmpv6_msg *msg = (struct icmpv6_msg *) from;
 268         struct sk_buff *org_skb = msg->skb;
 269         __wsum csum = 0;
 270
 271         csum = skb_copy_and_csum_bits(org_skb, msg->offset + offset,
 272                                       to, len, csum);
 273         skb->csum = csum_block_add(skb->csum, csum, odd);
 274         if (!(msg->type & ICMPV6_INFOMSG_MASK))
 275                 nf_ct_attach(skb, org_skb);
 276         return 0;
 277 }
 278
 279 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
 280 static void mip6_addr_swap(struct sk_buff *skb)
 281 {
 282         struct ipv6hdr *iph = ipv6_hdr(skb);
 283         struct inet6_skb_parm *opt = IP6CB(skb);
 284         struct ipv6_destopt_hao *hao;
 285         struct in6_addr tmp;
 286         int off;
 287
 288         if (opt->dsthao) {
 289                 off = ipv6_find_tlv(skb, opt->dsthao, IPV6_TLV_HAO);
 290                 if (likely(off >= 0)) {
 291                         hao = (struct ipv6_destopt_hao *)
 292                                         (skb_network_header(skb) + off);
 293                         ipv6_addr_copy(&tmp, &iph->saddr);
 294                         ipv6_addr_copy(&iph->saddr, &hao->addr);
 295                         ipv6_addr_copy(&hao->addr, &tmp);
 296                 }
 297         }
 298 }
 299 #else
 300 static inline void mip6_addr_swap(struct sk_buff *skb) {}
 301 #endif
 302
 303 static struct dst_entry *icmpv6_route_lookup(struct net *net, struct sk_buff *skb,
 304                                              struct sock *sk, struct flowi6 *fl6)
 305 {
 306         struct dst_entry *dst, *dst2;
 307         struct flowi6 fl2;
 308         int err;
 309
 310         err = ip6_dst_lookup(sk, &dst, fl6);
 311         if (err)
 312                 return ERR_PTR(err);
 313
 314         /*
 315          * We won't send icmp if the destination is known
 316          * anycast.
 317          */
 318         if (((struct rt6_info *)dst)->rt6i_flags & RTF_ANYCAST) {
 319                 LIMIT_NETDEBUG(KERN_DEBUG "icmpv6_send: acast source\n");
 320                 dst_release(dst);
 321                 return ERR_PTR(-EINVAL);
 322         }
 323
 324         /* No need to clone since we're just using its address. */
 325         dst2 = dst;
 326
 327         dst = xfrm_lookup(net, dst, flowi6_to_flowi(fl6), sk, 0);
 328         if (!IS_ERR(dst)) {
 329                 if (dst != dst2)
 330                         return dst;
 331         } else {
 332                 if (PTR_ERR(dst) == -EPERM)
 333                         dst = NULL;
 334                 else
 335                         return dst;
 336         }
 337
 338         err = xfrm_decode_session_reverse(skb, flowi6_to_flowi(&fl2), AF_INET6);
 339         if (err)
 340                 goto relookup_failed;
 341
 342         err = ip6_dst_lookup(sk, &dst2, &fl2);
 343         if (err)
 344                 goto relookup_failed;
 345
 346         dst2 = xfrm_lookup(net, dst2, flowi6_to_flowi(&fl2), sk, XFRM_LOOKUP_ICMP);
 347         if (!IS_ERR(dst2)) {
 348                 dst_release(dst);
 349                 dst = dst2;
 350         } else {
 351                 err = PTR_ERR(dst2);
 352                 if (err == -EPERM) {
 353                         dst_release(dst);
 354                         return dst2;
 355                 } else
 356                         goto relookup_failed;
 357         }
 358
 359 relookup_failed:
 360         if (dst)
 361                 return dst;
 362         return ERR_PTR(err);
 363 }
 364
 365 /*
 366  *      Send an ICMP message in response to a packet in error
 367  */
 368 void icmpv6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info)
 369 {
 370         struct net *net = dev_net(skb->dev);
 371         struct inet6_dev *idev = NULL;
 372         struct ipv6hdr *hdr = ipv6_hdr(skb);
 373         struct sock *sk;
 374         struct ipv6_pinfo *np;
 375         const struct in6_addr *saddr = NULL;
 376         struct dst_entry *dst;
 377         struct icmp6hdr tmp_hdr;
 378         struct flowi6 fl6;
 379         struct icmpv6_msg msg;
 380         int iif = 0;
 381         int addr_type = 0;
 382         int len;
 383         int hlimit;
 384         int err = 0;
 385
 386         if ((u8 *)hdr < skb->head ||
 387             (skb->network_header + sizeof(*hdr)) > skb->tail)
 388                 return;
 389
 390         /*
 391          *      Make sure we respect the rules
 392          *      i.e. RFC 1885 2.4(e)
 393          *      Rule (e.1) is enforced by not using icmpv6_send
 394          *      in any code that processes icmp errors.
 395          */
 396         addr_type = ipv6_addr_type(&hdr->daddr);
 397
 398         if (ipv6_chk_addr(net, &hdr->daddr, skb->dev, 0))
 399                 saddr = &hdr->daddr;
 400
 401         /*
 402          *      Dest addr check
 403          */
 404
 405         if ((addr_type & IPV6_ADDR_MULTICAST || skb->pkt_type != PACKET_HOST)) {
 406                 if (type != ICMPV6_PKT_TOOBIG &&
 407                     !(type == ICMPV6_PARAMPROB &&
 408                       code == ICMPV6_UNK_OPTION &&
 409                       (opt_unrec(skb, info))))
 410                         return;
 411
 412                 saddr = NULL;
 413         }
 414
 415         addr_type = ipv6_addr_type(&hdr->saddr);
 416
 417         /*
 418          *      Source addr check
 419          */
 420
 421         if (addr_type & IPV6_ADDR_LINKLOCAL)
 422                 iif = skb->dev->ifindex;
 423
 424         /*
 425          *      Must not send error if the source does not uniquely
 426          *      identify a single node (RFC2463 Section 2.4).
 427          *      We check unspecified / multicast addresses here,
 428          *      and anycast addresses will be checked later.
 429          */
 430         if ((addr_type == IPV6_ADDR_ANY) || (addr_type & IPV6_ADDR_MULTICAST)) {
 431                 LIMIT_NETDEBUG(KERN_DEBUG "icmpv6_send: addr_any/mcast source\n");
 432                 return;
 433         }
 434
 435         /*
 436          *      Never answer to a ICMP packet.
 437          */
 438         if (is_ineligible(skb)) {
 439                 LIMIT_NETDEBUG(KERN_DEBUG "icmpv6_send: no reply to icmp error\n");
 440                 return;
 441         }
 442
 443         mip6_addr_swap(skb);
 444
 445         memset(&fl6, 0, sizeof(fl6));
 446         fl6.flowi6_proto = IPPROTO_ICMPV6;
 447         ipv6_addr_copy(&fl6.daddr, &hdr->saddr);
 448         if (saddr)
 449                 ipv6_addr_copy(&fl6.saddr, saddr);
 450         fl6.flowi6_oif = iif;
 451         fl6.fl6_icmp_type = type;
 452         fl6.fl6_icmp_code = code;
 453         security_skb_classify_flow(skb, flowi6_to_flowi(&fl6));
 454
 455         sk = icmpv6_xmit_lock(net);
 456         if (sk == NULL)
 457                 return;
 458         np = inet6_sk(sk);
 459
 460         if (!icmpv6_xrlim_allow(sk, type, &fl6))
 461                 goto out;
 462
 463         tmp_hdr.icmp6_type = type;
 464         tmp_hdr.icmp6_code = code;
 465         tmp_hdr.icmp6_cksum = 0;
 466         tmp_hdr.icmp6_pointer = htonl(info);
 467
 468         if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr))
 469                 fl6.flowi6_oif = np->mcast_oif;
 470
 471         dst = icmpv6_route_lookup(net, skb, sk, &fl6);
 472         if (IS_ERR(dst))
 473                 goto out;
 474
 475         if (ipv6_addr_is_multicast(&fl6.daddr))
 476                 hlimit = np->mcast_hops;
 477         else
 478                 hlimit = np->hop_limit;
 479         if (hlimit < 0)
 480                 hlimit = ip6_dst_hoplimit(dst);
 481
 482         msg.skb = skb;
 483         msg.offset = skb_network_offset(skb);
 484         msg.type = type;
 485
 486         len = skb->len - msg.offset;
 487         len = min_t(unsigned int, len, IPV6_MIN_MTU - sizeof(struct ipv6hdr) -sizeof(struct icmp6hdr));
 488         if (len < 0) {
 489                 LIMIT_NETDEBUG(KERN_DEBUG "icmp: len problem\n");
 490                 goto out_dst_release;
 491         }
 492
 493         idev = in6_dev_get(skb->dev);
 494
 495         err = ip6_append_data(sk, icmpv6_getfrag, &msg,
 496                               len + sizeof(struct icmp6hdr),
 497                               sizeof(struct icmp6hdr), hlimit,
 498                               np->tclass, NULL, &fl6, (struct rt6_info*)dst,
 499                               MSG_DONTWAIT, np->dontfrag);
 500         if (err) {
 501                 ICMP6_INC_STATS_BH(net, idev, ICMP6_MIB_OUTERRORS);
 502                 ip6_flush_pending_frames(sk);
 503                 goto out_put;
 504         }
 505         err = icmpv6_push_pending_frames(sk, &fl6, &tmp_hdr, len + sizeof(struct icmp6hdr));
 506
 507 out_put:
 508         if (likely(idev != NULL))
 509                 in6_dev_put(idev);
 510 out_dst_release:
 511         dst_release(dst);
 512 out:
 513         icmpv6_xmit_unlock(sk);
 514 }
 515
 516 EXPORT_SYMBOL(icmpv6_send);
 517
 518 static void icmpv6_echo_reply(struct sk_buff *skb)
 519 {
 520         struct net *net = dev_net(skb->dev);
 521         struct sock *sk;
 522         struct inet6_dev *idev;
 523         struct ipv6_pinfo *np;
 524         const struct in6_addr *saddr = NULL;
 525         struct icmp6hdr *icmph = icmp6_hdr(skb);
 526         struct icmp6hdr tmp_hdr;
 527         struct flowi6 fl6;
 528         struct icmpv6_msg msg;
 529         struct dst_entry *dst;
 530         int err = 0;
 531         int hlimit;
 532
 533         saddr = &ipv6_hdr(skb)->daddr;
 534
 535         if (!ipv6_unicast_destination(skb))
 536                 saddr = NULL;
 537
 538         memcpy(&tmp_hdr, icmph, sizeof(tmp_hdr));
 539         tmp_hdr.icmp6_type = ICMPV6_ECHO_REPLY;
 540
 541         memset(&fl6, 0, sizeof(fl6));
 542         fl6.flowi6_proto = IPPROTO_ICMPV6;
 543         ipv6_addr_copy(&fl6.daddr, &ipv6_hdr(skb)->saddr);
 544         if (saddr)
 545                 ipv6_addr_copy(&fl6.saddr, saddr);
 546         fl6.flowi6_oif = skb->dev->ifindex;
 547         fl6.fl6_icmp_type = ICMPV6_ECHO_REPLY;
 548         security_skb_classify_flow(skb, flowi6_to_flowi(&fl6));
 549
 550         sk = icmpv6_xmit_lock(net);
 551         if (sk == NULL)
 552                 return;
 553         np = inet6_sk(sk);
 554
 555         if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr))
 556                 fl6.flowi6_oif = np->mcast_oif;
 557
 558         err = ip6_dst_lookup(sk, &dst, &fl6);
 559         if (err)
 560                 goto out;
 561         dst = xfrm_lookup(net, dst, flowi6_to_flowi(&fl6), sk, 0);
 562         if (IS_ERR(dst))
 563                 goto out;
 564
 565         if (ipv6_addr_is_multicast(&fl6.daddr))
 566                 hlimit = np->mcast_hops;
 567         else
 568                 hlimit = np->hop_limit;
 569         if (hlimit < 0)
 570                 hlimit = ip6_dst_hoplimit(dst);
 571
 572         idev = in6_dev_get(skb->dev);
 573
 574         msg.skb = skb;
 575         msg.offset = 0;
 576         msg.type = ICMPV6_ECHO_REPLY;
 577
 578         err = ip6_append_data(sk, icmpv6_getfrag, &msg, skb->len + sizeof(struct icmp6hdr),
 579                                 sizeof(struct icmp6hdr), hlimit, np->tclass, NULL, &fl6,
 580                                 (struct rt6_info*)dst, MSG_DONTWAIT,
 581                                 np->dontfrag);
 582
 583         if (err) {
 584                 ICMP6_INC_STATS_BH(net, idev, ICMP6_MIB_OUTERRORS);
 585                 ip6_flush_pending_frames(sk);
 586                 goto out_put;
 587         }
 588         err = icmpv6_push_pending_frames(sk, &fl6, &tmp_hdr, skb->len + sizeof(struct icmp6hdr));
 589
 590 out_put:
 591         if (likely(idev != NULL))
 592                 in6_dev_put(idev);
 593         dst_release(dst);
 594 out:
 595         icmpv6_xmit_unlock(sk);
 596 }
 597
 598 static void icmpv6_notify(struct sk_buff *skb, u8 type, u8 code, __be32 info)
 599 {
 600         const struct inet6_protocol *ipprot;
 601         int inner_offset;
 602         int hash;
 603         u8 nexthdr;
 604
 605         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
 606                 return;
 607
 608         nexthdr = ((struct ipv6hdr *)skb->data)->nexthdr;
 609         if (ipv6_ext_hdr(nexthdr)) {
 610                 /* now skip over extension headers */
 611                 inner_offset = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &nexthdr);
 612                 if (inner_offset<0)
 613                         return;
 614         } else {
 615                 inner_offset = sizeof(struct ipv6hdr);
 616         }
 617
 618         /* Checkin header including 8 bytes of inner protocol header. */
 619         if (!pskb_may_pull(skb, inner_offset+8))
 620                 return;
 621
 622         /* BUGGG_FUTURE: we should try to parse exthdrs in this packet.
 623            Without this we will not able f.e. to make source routed
 624            pmtu discovery.
 625            Corresponding argument (opt) to notifiers is already added.
 626            --ANK (980726)
 627          */
 628
 629         hash = nexthdr & (MAX_INET_PROTOS - 1);
 630
 631         rcu_read_lock();
 632         ipprot = rcu_dereference(inet6_protos[hash]);
 633         if (ipprot && ipprot->err_handler)
 634                 ipprot->err_handler(skb, NULL, type, code, inner_offset, info);
 635         rcu_read_unlock();
 636
 637         raw6_icmp_error(skb, nexthdr, type, code, inner_offset, info);
 638 }
 639
 640 /*
 641  *      Handle icmp messages
 642  */
 643
 644 static int icmpv6_rcv(struct sk_buff *skb)
 645 {
 646         struct net_device *dev = skb->dev;
 647         struct inet6_dev *idev = __in6_dev_get(dev);
 648         const struct in6_addr *saddr, *daddr;
 649         const struct ipv6hdr *orig_hdr;
 650         struct icmp6hdr *hdr;
 651         u8 type;
 652
 653         if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
 654                 struct sec_path *sp = skb_sec_path(skb);
 655                 int nh;
 656
 657                 if (!(sp && sp->xvec[sp->len - 1]->props.flags &
 658                                  XFRM_STATE_ICMP))
 659                         goto drop_no_count;
 660
 661                 if (!pskb_may_pull(skb, sizeof(*hdr) + sizeof(*orig_hdr)))
 662                         goto drop_no_count;
 663
 664                 nh = skb_network_offset(skb);
 665                 skb_set_network_header(skb, sizeof(*hdr));
 666
 667                 if (!xfrm6_policy_check_reverse(NULL, XFRM_POLICY_IN, skb))
 668                         goto drop_no_count;
 669
 670                 skb_set_network_header(skb, nh);
 671         }
 672
 673         ICMP6_INC_STATS_BH(dev_net(dev), idev, ICMP6_MIB_INMSGS);
 674
 675         saddr = &ipv6_hdr(skb)->saddr;
 676         daddr = &ipv6_hdr(skb)->daddr;
 677
 678         /* Perform checksum. */
 679         switch (skb->ip_summed) {
 680         case CHECKSUM_COMPLETE:
 681                 if (!csum_ipv6_magic(saddr, daddr, skb->len, IPPROTO_ICMPV6,
 682                                      skb->csum))
 683                         break;
 684                 /* fall through */
 685         case CHECKSUM_NONE:
 686                 skb->csum = ~csum_unfold(csum_ipv6_magic(saddr, daddr, skb->len,
 687                                              IPPROTO_ICMPV6, 0));
 688                 if (__skb_checksum_complete(skb)) {
 689                         LIMIT_NETDEBUG(KERN_DEBUG "ICMPv6 checksum failed [%pI6 > %pI6]\n",
 690                                        saddr, daddr);
 691                         goto discard_it;
 692                 }
 693         }
 694
 695         if (!pskb_pull(skb, sizeof(*hdr)))
 696                 goto discard_it;
 697
 698         hdr = icmp6_hdr(skb);
 699
 700         type = hdr->icmp6_type;
 701
 702         ICMP6MSGIN_INC_STATS_BH(dev_net(dev), idev, type);
 703
 704         switch (type) {
 705         case ICMPV6_ECHO_REQUEST:
 706                 icmpv6_echo_reply(skb);
 707                 break;
 708
 709         case ICMPV6_ECHO_REPLY:
 710                 /* we couldn't care less */
 711                 break;
 712
 713         case ICMPV6_PKT_TOOBIG:
 714                 /* BUGGG_FUTURE: if packet contains rthdr, we cannot update
 715                    standard destination cache. Seems, only "advanced"
 716                    destination cache will allow to solve this problem
 717                    --ANK (980726)
 718                  */
 719                 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
 720                         goto discard_it;
 721                 hdr = icmp6_hdr(skb);
 722                 orig_hdr = (struct ipv6hdr *) (hdr + 1);
 723                 rt6_pmtu_discovery(&orig_hdr->daddr, &orig_hdr->saddr, dev,
 724                                    ntohl(hdr->icmp6_mtu));
 725
 726                 /*
 727                  *      Drop through to notify
 728                  */
 729
 730         case ICMPV6_DEST_UNREACH:
 731         case ICMPV6_TIME_EXCEED:
 732         case ICMPV6_PARAMPROB:
 733                 icmpv6_notify(skb, type, hdr->icmp6_code, hdr->icmp6_mtu);
 734                 break;
 735
 736         case NDISC_ROUTER_SOLICITATION:
 737         case NDISC_ROUTER_ADVERTISEMENT:
 738         case NDISC_NEIGHBOUR_SOLICITATION:
 739         case NDISC_NEIGHBOUR_ADVERTISEMENT:
 740         case NDISC_REDIRECT:
 741                 ndisc_rcv(skb);
 742                 break;
 743
 744         case ICMPV6_MGM_QUERY:
 745                 igmp6_event_query(skb);
 746                 break;
 747
 748         case ICMPV6_MGM_REPORT:
 749                 igmp6_event_report(skb);
 750                 break;
 751
 752         case ICMPV6_MGM_REDUCTION:
 753         case ICMPV6_NI_QUERY:
 754         case ICMPV6_NI_REPLY:
 755         case ICMPV6_MLD2_REPORT:
 756         case ICMPV6_DHAAD_REQUEST:
 757         case ICMPV6_DHAAD_REPLY:
 758         case ICMPV6_MOBILE_PREFIX_SOL:
 759         case ICMPV6_MOBILE_PREFIX_ADV:
 760                 break;
 761
 762         default:
 763                 LIMIT_NETDEBUG(KERN_DEBUG "icmpv6: msg of unknown type\n");
 764
 765                 /* informational */
 766                 if (type & ICMPV6_INFOMSG_MASK)
 767                         break;
 768
 769                 /*
 770                  * error of unknown type.
 771                  * must pass to upper level
 772                  */
 773
 774                 icmpv6_notify(skb, type, hdr->icmp6_code, hdr->icmp6_mtu);
 775         }
 776
 777         kfree_skb(skb);
 778         return 0;
 779
 780 discard_it:
 781         ICMP6_INC_STATS_BH(dev_net(dev), idev, ICMP6_MIB_INERRORS);
 782 drop_no_count:
 783         kfree_skb(skb);
 784         return 0;
 785 }
 786
 787 void icmpv6_flow_init(struct sock *sk, struct flowi6 *fl6,
 788                       u8 type,
 789                       const struct in6_addr *saddr,
 790                       const struct in6_addr *daddr,
 791                       int oif)
 792 {
 793         memset(fl6, 0, sizeof(*fl6));
 794         ipv6_addr_copy(&fl6->saddr, saddr);
 795         ipv6_addr_copy(&fl6->daddr, daddr);
 796         fl6->flowi6_proto       = IPPROTO_ICMPV6;
 797         fl6->fl6_icmp_type      = type;
 798         fl6->fl6_icmp_code      = 0;
 799         fl6->flowi6_oif         = oif;
 800         security_sk_classify_flow(sk, flowi6_to_flowi(fl6));
 801 }
 802
 803 /*
 804  * Special lock-class for __icmpv6_sk:
 805  */
 806 static struct lock_class_key icmpv6_socket_sk_dst_lock_key;
 807
 808 static int __net_init icmpv6_sk_init(struct net *net)
 809 {
 810         struct sock *sk;
 811         int err, i, j;
 812
 813         net->ipv6.icmp_sk =
 814                 kzalloc(nr_cpu_ids * sizeof(struct sock *), GFP_KERNEL);
 815         if (net->ipv6.icmp_sk == NULL)
 816                 return -ENOMEM;
 817
 818         for_each_possible_cpu(i) {
 819                 err = inet_ctl_sock_create(&sk, PF_INET6,
 820                                            SOCK_RAW, IPPROTO_ICMPV6, net);
 821                 if (err < 0) {
 822                         printk(KERN_ERR
 823                                "Failed to initialize the ICMP6 control socket "
 824                                "(err %d).\n",
 825                                err);
 826                         goto fail;
 827                 }
 828
 829                 net->ipv6.icmp_sk[i] = sk;
 830
 831                 /*
 832                  * Split off their lock-class, because sk->sk_dst_lock
 833                  * gets used from softirqs, which is safe for
 834                  * __icmpv6_sk (because those never get directly used
 835                  * via userspace syscalls), but unsafe for normal sockets.
 836                  */
 837                 lockdep_set_class(&sk->sk_dst_lock,
 838                                   &icmpv6_socket_sk_dst_lock_key);
 839
 840                 /* Enough space for 2 64K ICMP packets, including
 841                  * sk_buff struct overhead.
 842                  */
 843                 sk->sk_sndbuf =
 844                         (2 * ((64 * 1024) + sizeof(struct sk_buff)));
 845         }
 846         return 0;
 847
 848  fail:
 849         for (j = 0; j < i; j++)
 850                 inet_ctl_sock_destroy(net->ipv6.icmp_sk[j]);
 851         kfree(net->ipv6.icmp_sk);
 852         return err;
 853 }
 854
 855 static void __net_exit icmpv6_sk_exit(struct net *net)
 856 {
 857         int i;
 858
 859         for_each_possible_cpu(i) {
 860                 inet_ctl_sock_destroy(net->ipv6.icmp_sk[i]);
 861         }
 862         kfree(net->ipv6.icmp_sk);
 863 }
 864
 865 static struct pernet_operations icmpv6_sk_ops = {
 866        .init = icmpv6_sk_init,
 867        .exit = icmpv6_sk_exit,
 868 };
 869
 870 int __init icmpv6_init(void)
 871 {
 872         int err;
 873
 874         err = register_pernet_subsys(&icmpv6_sk_ops);
 875         if (err < 0)
 876                 return err;
 877
 878         err = -EAGAIN;
 879         if (inet6_add_protocol(&icmpv6_protocol, IPPROTO_ICMPV6) < 0)
 880                 goto fail;
 881         return 0;
 882
 883 fail:
 884         printk(KERN_ERR "Failed to register ICMP6 protocol\n");
 885         unregister_pernet_subsys(&icmpv6_sk_ops);
 886         return err;
 887 }
 888
 889 void icmpv6_cleanup(void)
 890 {
 891         unregister_pernet_subsys(&icmpv6_sk_ops);
 892         inet6_del_protocol(&icmpv6_protocol, IPPROTO_ICMPV6);
 893 }
 894
 895
 896 static const struct icmp6_err {
 897         int err;
 898         int fatal;
 899 } tab_unreach[] = {
 900         {       /* NOROUTE */
 901                 .err    = ENETUNREACH,
 902                 .fatal  = 0,
 903         },
 904         {       /* ADM_PROHIBITED */
 905                 .err    = EACCES,
 906                 .fatal  = 1,
 907         },
 908         {       /* Was NOT_NEIGHBOUR, now reserved */
 909                 .err    = EHOSTUNREACH,
 910                 .fatal  = 0,
 911         },
 912         {       /* ADDR_UNREACH */
 913                 .err    = EHOSTUNREACH,
 914                 .fatal  = 0,
 915         },
 916         {       /* PORT_UNREACH */
 917                 .err    = ECONNREFUSED,
 918                 .fatal  = 1,
 919         },
 920 };
 921
 922 int icmpv6_err_convert(u8 type, u8 code, int *err)
 923 {
 924         int fatal = 0;
 925
 926         *err = EPROTO;
 927
 928         switch (type) {
 929         case ICMPV6_DEST_UNREACH:
 930                 fatal = 1;
 931                 if (code <= ICMPV6_PORT_UNREACH) {
 932                         *err  = tab_unreach[code].err;
 933                         fatal = tab_unreach[code].fatal;
 934                 }
 935                 break;
 936
 937         case ICMPV6_PKT_TOOBIG:
 938                 *err = EMSGSIZE;
 939                 break;
 940
 941         case ICMPV6_PARAMPROB:
 942                 *err = EPROTO;
 943                 fatal = 1;
 944                 break;
 945
 946         case ICMPV6_TIME_EXCEED:
 947                 *err = EHOSTUNREACH;
 948                 break;
 949         }
 950
 951         return fatal;
 952 }
 953
 954 EXPORT_SYMBOL(icmpv6_err_convert);
 955
 956 #ifdef CONFIG_SYSCTL
 957 ctl_table ipv6_icmp_table_template[] = {
 958         {
 959                 .procname       = "ratelimit",
 960                 .data           = &init_net.ipv6.sysctl.icmpv6_time,
 961                 .maxlen         = sizeof(int),
 962                 .mode           = 0644,
 963                 .proc_handler   = proc_dointvec_ms_jiffies,
 964         },
 965         { },
 966 };
 967
 968 struct ctl_table * __net_init ipv6_icmp_sysctl_init(struct net *net)
 969 {
 970         struct ctl_table *table;
 971
 972         table = kmemdup(ipv6_icmp_table_template,
 973                         sizeof(ipv6_icmp_table_template),
 974                         GFP_KERNEL);
 975
 976         if (table)
 977                 table[0].data = &net->ipv6.sysctl.icmpv6_time;
 978
 979         return table;
 980 }
 981 #endif
 982