net/ipv6/icmp.c

   1 /*
   2  *      Internet Control Message Protocol (ICMPv6)
   3  *      Linux INET6 implementation
   4  *
   5  *      Authors:
   6  *      Pedro Roque             <roque@di.fc.ul.pt>
   7  *
   8  *      $Id: icmp.c,v 1.38 2002/02/08 03:57:19 davem Exp $
   9  *
  10  *      Based on net/ipv4/icmp.c
  11  *
  12  *      RFC 1885
  13  *
  14  *      This program is free software; you can redistribute it and/or
  15  *      modify it under the terms of the GNU General Public License
  16  *      as published by the Free Software Foundation; either version
  17  *      2 of the License, or (at your option) any later version.
  18  */
  19
  20 /*
  21  *      Changes:
  22  *
  23  *      Andi Kleen              :       exception handling
  24  *      Andi Kleen                      add rate limits. never reply to a icmp.
  25  *                                      add more length checks and other fixes.
  26  *      yoshfuji                :       ensure to sent parameter problem for
  27  *                                      fragments.
  28  *      YOSHIFUJI Hideaki @USAGI:       added sysctl for icmp rate limit.
  29  *      Randy Dunlap and
  30  *      YOSHIFUJI Hideaki @USAGI:       Per-interface statistics support
  31  *      Kazunori MIYAZAWA @USAGI:       change output process to use ip6_append_data
  32  */
  33
  34 #include <linux/module.h>
  35 #include <linux/errno.h>
  36 #include <linux/types.h>
  37 #include <linux/socket.h>
  38 #include <linux/in.h>
  39 #include <linux/kernel.h>
  40 #include <linux/sockios.h>
  41 #include <linux/net.h>
  42 #include <linux/skbuff.h>
  43 #include <linux/init.h>
  44 #include <linux/netfilter.h>
  45
  46 #ifdef CONFIG_SYSCTL
  47 #include <linux/sysctl.h>
  48 #endif
  49
  50 #include <linux/inet.h>
  51 #include <linux/netdevice.h>
  52 #include <linux/icmpv6.h>
  53
  54 #include <net/ip.h>
  55 #include <net/sock.h>
  56
  57 #include <net/ipv6.h>
  58 #include <net/ip6_checksum.h>
  59 #include <net/protocol.h>
  60 #include <net/raw.h>
  61 #include <net/rawv6.h>
  62 #include <net/transp_v6.h>
  63 #include <net/ip6_route.h>
  64 #include <net/addrconf.h>
  65 #include <net/icmp.h>
  66 #include <net/xfrm.h>
  67
  68 #include <asm/uaccess.h>
  69 #include <asm/system.h>
  70
  71 DEFINE_SNMP_STAT(struct icmpv6_mib, icmpv6_statistics) __read_mostly;
  72 EXPORT_SYMBOL(icmpv6_statistics);
  73 DEFINE_SNMP_STAT(struct icmpv6msg_mib, icmpv6msg_statistics) __read_mostly;
  74 EXPORT_SYMBOL(icmpv6msg_statistics);
  75
  76 /*
  77  *      The ICMP socket(s). This is the most convenient way to flow control
  78  *      our ICMP output as well as maintain a clean interface throughout
  79  *      all layers. All Socketless IP sends will soon be gone.
  80  *
  81  *      On SMP we have one ICMP socket per-cpu.
  82  */
  83 static inline struct sock *icmpv6_sk(struct net *net)
  84 {
  85         return net->ipv6.icmp_sk[smp_processor_id()];
  86 }
  87
  88 static int icmpv6_rcv(struct sk_buff *skb);
  89
  90 static struct inet6_protocol icmpv6_protocol = {
  91         .handler        =       icmpv6_rcv,
  92         .flags          =       INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
  93 };
  94
  95 static __inline__ int icmpv6_xmit_lock(struct sock *sk)
  96 {
  97         local_bh_disable();
  98
  99         if (unlikely(!spin_trylock(&sk->sk_lock.slock))) {
 100                 /* This can happen if the output path (f.e. SIT or
 101                  * ip6ip6 tunnel) signals dst_link_failure() for an
 102                  * outgoing ICMP6 packet.
 103                  */
 104                 local_bh_enable();
 105                 return 1;
 106         }
 107         return 0;
 108 }
 109
 110 static __inline__ void icmpv6_xmit_unlock(struct sock *sk)
 111 {
 112         spin_unlock_bh(&sk->sk_lock.slock);
 113 }
 114
 115 /*
 116  * Slightly more convenient version of icmpv6_send.
 117  */
 118 void icmpv6_param_prob(struct sk_buff *skb, int code, int pos)
 119 {
 120         icmpv6_send(skb, ICMPV6_PARAMPROB, code, pos, skb->dev);
 121         kfree_skb(skb);
 122 }
 123
 124 /*
 125  * Figure out, may we reply to this packet with icmp error.
 126  *
 127  * We do not reply, if:
 128  *      - it was icmp error message.
 129  *      - it is truncated, so that it is known, that protocol is ICMPV6
 130  *        (i.e. in the middle of some exthdr)
 131  *
 132  *      --ANK (980726)
 133  */
 134
 135 static int is_ineligible(struct sk_buff *skb)
 136 {
 137         int ptr = (u8 *)(ipv6_hdr(skb) + 1) - skb->data;
 138         int len = skb->len - ptr;
 139         __u8 nexthdr = ipv6_hdr(skb)->nexthdr;
 140
 141         if (len < 0)
 142                 return 1;
 143
 144         ptr = ipv6_skip_exthdr(skb, ptr, &nexthdr);
 145         if (ptr < 0)
 146                 return 0;
 147         if (nexthdr == IPPROTO_ICMPV6) {
 148                 u8 _type, *tp;
 149                 tp = skb_header_pointer(skb,
 150                         ptr+offsetof(struct icmp6hdr, icmp6_type),
 151                         sizeof(_type), &_type);
 152                 if (tp == NULL ||
 153                     !(*tp & ICMPV6_INFOMSG_MASK))
 154                         return 1;
 155         }
 156         return 0;
 157 }
 158
 159 /*
 160  * Check the ICMP output rate limit
 161  */
 162 static inline int icmpv6_xrlim_allow(struct sock *sk, int type,
 163                                      struct flowi *fl)
 164 {
 165         struct dst_entry *dst;
 166         struct net *net = sk->sk_net;
 167         int res = 0;
 168
 169         /* Informational messages are not limited. */
 170         if (type & ICMPV6_INFOMSG_MASK)
 171                 return 1;
 172
 173         /* Do not limit pmtu discovery, it would break it. */
 174         if (type == ICMPV6_PKT_TOOBIG)
 175                 return 1;
 176
 177         /*
 178          * Look up the output route.
 179          * XXX: perhaps the expire for routing entries cloned by
 180          * this lookup should be more aggressive (not longer than timeout).
 181          */
 182         dst = ip6_route_output(net, sk, fl);
 183         if (dst->error) {
 184                 IP6_INC_STATS(ip6_dst_idev(dst),
 185                               IPSTATS_MIB_OUTNOROUTES);
 186         } else if (dst->dev && (dst->dev->flags&IFF_LOOPBACK)) {
 187                 res = 1;
 188         } else {
 189                 struct rt6_info *rt = (struct rt6_info *)dst;
 190                 int tmo = net->ipv6.sysctl.icmpv6_time;
 191
 192                 /* Give more bandwidth to wider prefixes. */
 193                 if (rt->rt6i_dst.plen < 128)
 194                         tmo >>= ((128 - rt->rt6i_dst.plen)>>5);
 195
 196                 res = xrlim_allow(dst, 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 flowi *fl, 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((char *)icmp6h,
 235                                         sizeof(struct icmp6hdr), skb->csum);
 236                 icmp6h->icmp6_cksum = csum_ipv6_magic(&fl->fl6_src,
 237                                                       &fl->fl6_dst,
 238                                                       len, fl->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((char *)icmp6h,
 248                                         sizeof(struct icmp6hdr), tmp_csum);
 249                 icmp6h->icmp6_cksum = csum_ipv6_magic(&fl->fl6_src,
 250                                                       &fl->fl6_dst,
 251                                                       len, fl->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 /*
 304  *      Send an ICMP message in response to a packet in error
 305  */
 306 void icmpv6_send(struct sk_buff *skb, int type, int code, __u32 info,
 307                  struct net_device *dev)
 308 {
 309         struct net *net = dev_net(skb->dev);
 310         struct inet6_dev *idev = NULL;
 311         struct ipv6hdr *hdr = ipv6_hdr(skb);
 312         struct sock *sk;
 313         struct ipv6_pinfo *np;
 314         struct in6_addr *saddr = NULL;
 315         struct dst_entry *dst;
 316         struct dst_entry *dst2;
 317         struct icmp6hdr tmp_hdr;
 318         struct flowi fl;
 319         struct flowi fl2;
 320         struct icmpv6_msg msg;
 321         int iif = 0;
 322         int addr_type = 0;
 323         int len;
 324         int hlimit, tclass;
 325         int err = 0;
 326
 327         if ((u8 *)hdr < skb->head ||
 328             (skb->network_header + sizeof(*hdr)) > skb->tail)
 329                 return;
 330
 331         /*
 332          *      Make sure we respect the rules
 333          *      i.e. RFC 1885 2.4(e)
 334          *      Rule (e.1) is enforced by not using icmpv6_send
 335          *      in any code that processes icmp errors.
 336          */
 337         addr_type = ipv6_addr_type(&hdr->daddr);
 338
 339         if (ipv6_chk_addr(net, &hdr->daddr, skb->dev, 0))
 340                 saddr = &hdr->daddr;
 341
 342         /*
 343          *      Dest addr check
 344          */
 345
 346         if ((addr_type & IPV6_ADDR_MULTICAST || skb->pkt_type != PACKET_HOST)) {
 347                 if (type != ICMPV6_PKT_TOOBIG &&
 348                     !(type == ICMPV6_PARAMPROB &&
 349                       code == ICMPV6_UNK_OPTION &&
 350                       (opt_unrec(skb, info))))
 351                         return;
 352
 353                 saddr = NULL;
 354         }
 355
 356         addr_type = ipv6_addr_type(&hdr->saddr);
 357
 358         /*
 359          *      Source addr check
 360          */
 361
 362         if (addr_type & IPV6_ADDR_LINKLOCAL)
 363                 iif = skb->dev->ifindex;
 364
 365         /*
 366          *      Must not send error if the source does not uniquely
 367          *      identify a single node (RFC2463 Section 2.4).
 368          *      We check unspecified / multicast addresses here,
 369          *      and anycast addresses will be checked later.
 370          */
 371         if ((addr_type == IPV6_ADDR_ANY) || (addr_type & IPV6_ADDR_MULTICAST)) {
 372                 LIMIT_NETDEBUG(KERN_DEBUG "icmpv6_send: addr_any/mcast source\n");
 373                 return;
 374         }
 375
 376         /*
 377          *      Never answer to a ICMP packet.
 378          */
 379         if (is_ineligible(skb)) {
 380                 LIMIT_NETDEBUG(KERN_DEBUG "icmpv6_send: no reply to icmp error\n");
 381                 return;
 382         }
 383
 384         mip6_addr_swap(skb);
 385
 386         memset(&fl, 0, sizeof(fl));
 387         fl.proto = IPPROTO_ICMPV6;
 388         ipv6_addr_copy(&fl.fl6_dst, &hdr->saddr);
 389         if (saddr)
 390                 ipv6_addr_copy(&fl.fl6_src, saddr);
 391         fl.oif = iif;
 392         fl.fl_icmp_type = type;
 393         fl.fl_icmp_code = code;
 394         security_skb_classify_flow(skb, &fl);
 395
 396         sk = icmpv6_sk(net);
 397         np = inet6_sk(sk);
 398
 399         if (icmpv6_xmit_lock(sk))
 400                 return;
 401
 402         if (!icmpv6_xrlim_allow(sk, type, &fl))
 403                 goto out;
 404
 405         tmp_hdr.icmp6_type = type;
 406         tmp_hdr.icmp6_code = code;
 407         tmp_hdr.icmp6_cksum = 0;
 408         tmp_hdr.icmp6_pointer = htonl(info);
 409
 410         if (!fl.oif && ipv6_addr_is_multicast(&fl.fl6_dst))
 411                 fl.oif = np->mcast_oif;
 412
 413         err = ip6_dst_lookup(sk, &dst, &fl);
 414         if (err)
 415                 goto out;
 416
 417         /*
 418          * We won't send icmp if the destination is known
 419          * anycast.
 420          */
 421         if (((struct rt6_info *)dst)->rt6i_flags & RTF_ANYCAST) {
 422                 LIMIT_NETDEBUG(KERN_DEBUG "icmpv6_send: acast source\n");
 423                 goto out_dst_release;
 424         }
 425
 426         /* No need to clone since we're just using its address. */
 427         dst2 = dst;
 428
 429         err = xfrm_lookup(&dst, &fl, sk, 0);
 430         switch (err) {
 431         case 0:
 432                 if (dst != dst2)
 433                         goto route_done;
 434                 break;
 435         case -EPERM:
 436                 dst = NULL;
 437                 break;
 438         default:
 439                 goto out;
 440         }
 441
 442         if (xfrm_decode_session_reverse(skb, &fl2, AF_INET6))
 443                 goto out;
 444
 445         if (ip6_dst_lookup(sk, &dst2, &fl))
 446                 goto out;
 447
 448         err = xfrm_lookup(&dst2, &fl, sk, XFRM_LOOKUP_ICMP);
 449         if (err == -ENOENT) {
 450                 if (!dst)
 451                         goto out;
 452                 goto route_done;
 453         }
 454
 455         dst_release(dst);
 456         dst = dst2;
 457
 458         if (err)
 459                 goto out;
 460
 461 route_done:
 462         if (ipv6_addr_is_multicast(&fl.fl6_dst))
 463                 hlimit = np->mcast_hops;
 464         else
 465                 hlimit = np->hop_limit;
 466         if (hlimit < 0)
 467                 hlimit = ip6_dst_hoplimit(dst);
 468
 469         tclass = np->tclass;
 470         if (tclass < 0)
 471                 tclass = 0;
 472
 473         msg.skb = skb;
 474         msg.offset = skb_network_offset(skb);
 475         msg.type = type;
 476
 477         len = skb->len - msg.offset;
 478         len = min_t(unsigned int, len, IPV6_MIN_MTU - sizeof(struct ipv6hdr) -sizeof(struct icmp6hdr));
 479         if (len < 0) {
 480                 LIMIT_NETDEBUG(KERN_DEBUG "icmp: len problem\n");
 481                 goto out_dst_release;
 482         }
 483
 484         idev = in6_dev_get(skb->dev);
 485
 486         err = ip6_append_data(sk, icmpv6_getfrag, &msg,
 487                               len + sizeof(struct icmp6hdr),
 488                               sizeof(struct icmp6hdr),
 489                               hlimit, tclass, NULL, &fl, (struct rt6_info*)dst,
 490                               MSG_DONTWAIT);
 491         if (err) {
 492                 ip6_flush_pending_frames(sk);
 493                 goto out_put;
 494         }
 495         err = icmpv6_push_pending_frames(sk, &fl, &tmp_hdr, len + sizeof(struct icmp6hdr));
 496
 497 out_put:
 498         if (likely(idev != NULL))
 499                 in6_dev_put(idev);
 500 out_dst_release:
 501         dst_release(dst);
 502 out:
 503         icmpv6_xmit_unlock(sk);
 504 }
 505
 506 EXPORT_SYMBOL(icmpv6_send);
 507
 508 static void icmpv6_echo_reply(struct sk_buff *skb)
 509 {
 510         struct net *net = dev_net(skb->dev);
 511         struct sock *sk;
 512         struct inet6_dev *idev;
 513         struct ipv6_pinfo *np;
 514         struct in6_addr *saddr = NULL;
 515         struct icmp6hdr *icmph = icmp6_hdr(skb);
 516         struct icmp6hdr tmp_hdr;
 517         struct flowi fl;
 518         struct icmpv6_msg msg;
 519         struct dst_entry *dst;
 520         int err = 0;
 521         int hlimit;
 522         int tclass;
 523
 524         saddr = &ipv6_hdr(skb)->daddr;
 525
 526         if (!ipv6_unicast_destination(skb))
 527                 saddr = NULL;
 528
 529         memcpy(&tmp_hdr, icmph, sizeof(tmp_hdr));
 530         tmp_hdr.icmp6_type = ICMPV6_ECHO_REPLY;
 531
 532         memset(&fl, 0, sizeof(fl));
 533         fl.proto = IPPROTO_ICMPV6;
 534         ipv6_addr_copy(&fl.fl6_dst, &ipv6_hdr(skb)->saddr);
 535         if (saddr)
 536                 ipv6_addr_copy(&fl.fl6_src, saddr);
 537         fl.oif = skb->dev->ifindex;
 538         fl.fl_icmp_type = ICMPV6_ECHO_REPLY;
 539         security_skb_classify_flow(skb, &fl);
 540
 541         sk = icmpv6_sk(net);
 542         np = inet6_sk(sk);
 543
 544         if (icmpv6_xmit_lock(sk))
 545                 return;
 546
 547         if (!fl.oif && ipv6_addr_is_multicast(&fl.fl6_dst))
 548                 fl.oif = np->mcast_oif;
 549
 550         err = ip6_dst_lookup(sk, &dst, &fl);
 551         if (err)
 552                 goto out;
 553         if ((err = xfrm_lookup(&dst, &fl, sk, 0)) < 0)
 554                 goto out;
 555
 556         if (ipv6_addr_is_multicast(&fl.fl6_dst))
 557                 hlimit = np->mcast_hops;
 558         else
 559                 hlimit = np->hop_limit;
 560         if (hlimit < 0)
 561                 hlimit = ip6_dst_hoplimit(dst);
 562
 563         tclass = np->tclass;
 564         if (tclass < 0)
 565                 tclass = 0;
 566
 567         idev = in6_dev_get(skb->dev);
 568
 569         msg.skb = skb;
 570         msg.offset = 0;
 571         msg.type = ICMPV6_ECHO_REPLY;
 572
 573         err = ip6_append_data(sk, icmpv6_getfrag, &msg, skb->len + sizeof(struct icmp6hdr),
 574                                 sizeof(struct icmp6hdr), hlimit, tclass, NULL, &fl,
 575                                 (struct rt6_info*)dst, MSG_DONTWAIT);
 576
 577         if (err) {
 578                 ip6_flush_pending_frames(sk);
 579                 goto out_put;
 580         }
 581         err = icmpv6_push_pending_frames(sk, &fl, &tmp_hdr, skb->len + sizeof(struct icmp6hdr));
 582
 583 out_put:
 584         if (likely(idev != NULL))
 585                 in6_dev_put(idev);
 586         dst_release(dst);
 587 out:
 588         icmpv6_xmit_unlock(sk);
 589 }
 590
 591 static void icmpv6_notify(struct sk_buff *skb, int type, int code, __be32 info)
 592 {
 593         struct inet6_protocol *ipprot;
 594         int inner_offset;
 595         int hash;
 596         u8 nexthdr;
 597
 598         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
 599                 return;
 600
 601         nexthdr = ((struct ipv6hdr *)skb->data)->nexthdr;
 602         if (ipv6_ext_hdr(nexthdr)) {
 603                 /* now skip over extension headers */
 604                 inner_offset = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &nexthdr);
 605                 if (inner_offset<0)
 606                         return;
 607         } else {
 608                 inner_offset = sizeof(struct ipv6hdr);
 609         }
 610
 611         /* Checkin header including 8 bytes of inner protocol header. */
 612         if (!pskb_may_pull(skb, inner_offset+8))
 613                 return;
 614
 615         /* BUGGG_FUTURE: we should try to parse exthdrs in this packet.
 616            Without this we will not able f.e. to make source routed
 617            pmtu discovery.
 618            Corresponding argument (opt) to notifiers is already added.
 619            --ANK (980726)
 620          */
 621
 622         hash = nexthdr & (MAX_INET_PROTOS - 1);
 623
 624         rcu_read_lock();
 625         ipprot = rcu_dereference(inet6_protos[hash]);
 626         if (ipprot && ipprot->err_handler)
 627                 ipprot->err_handler(skb, NULL, type, code, inner_offset, info);
 628         rcu_read_unlock();
 629
 630         raw6_icmp_error(skb, nexthdr, type, code, inner_offset, info);
 631 }
 632
 633 /*
 634  *      Handle icmp messages
 635  */
 636
 637 static int icmpv6_rcv(struct sk_buff *skb)
 638 {
 639         struct net_device *dev = skb->dev;
 640         struct inet6_dev *idev = __in6_dev_get(dev);
 641         struct in6_addr *saddr, *daddr;
 642         struct ipv6hdr *orig_hdr;
 643         struct icmp6hdr *hdr;
 644         int type;
 645
 646         if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
 647                 int nh;
 648
 649                 if (!(skb->sp && skb->sp->xvec[skb->sp->len - 1]->props.flags &
 650                                  XFRM_STATE_ICMP))
 651                         goto drop_no_count;
 652
 653                 if (!pskb_may_pull(skb, sizeof(*hdr) + sizeof(*orig_hdr)))
 654                         goto drop_no_count;
 655
 656                 nh = skb_network_offset(skb);
 657                 skb_set_network_header(skb, sizeof(*hdr));
 658
 659                 if (!xfrm6_policy_check_reverse(NULL, XFRM_POLICY_IN, skb))
 660                         goto drop_no_count;
 661
 662                 skb_set_network_header(skb, nh);
 663         }
 664
 665         ICMP6_INC_STATS_BH(idev, ICMP6_MIB_INMSGS);
 666
 667         saddr = &ipv6_hdr(skb)->saddr;
 668         daddr = &ipv6_hdr(skb)->daddr;
 669
 670         /* Perform checksum. */
 671         switch (skb->ip_summed) {
 672         case CHECKSUM_COMPLETE:
 673                 if (!csum_ipv6_magic(saddr, daddr, skb->len, IPPROTO_ICMPV6,
 674                                      skb->csum))
 675                         break;
 676                 /* fall through */
 677         case CHECKSUM_NONE:
 678                 skb->csum = ~csum_unfold(csum_ipv6_magic(saddr, daddr, skb->len,
 679                                              IPPROTO_ICMPV6, 0));
 680                 if (__skb_checksum_complete(skb)) {
 681                         LIMIT_NETDEBUG(KERN_DEBUG "ICMPv6 checksum failed [" NIP6_FMT " > " NIP6_FMT "]\n",
 682                                        NIP6(*saddr), NIP6(*daddr));
 683                         goto discard_it;
 684                 }
 685         }
 686
 687         if (!pskb_pull(skb, sizeof(*hdr)))
 688                 goto discard_it;
 689
 690         hdr = icmp6_hdr(skb);
 691
 692         type = hdr->icmp6_type;
 693
 694         ICMP6MSGIN_INC_STATS_BH(idev, type);
 695
 696         switch (type) {
 697         case ICMPV6_ECHO_REQUEST:
 698                 icmpv6_echo_reply(skb);
 699                 break;
 700
 701         case ICMPV6_ECHO_REPLY:
 702                 /* we couldn't care less */
 703                 break;
 704
 705         case ICMPV6_PKT_TOOBIG:
 706                 /* BUGGG_FUTURE: if packet contains rthdr, we cannot update
 707                    standard destination cache. Seems, only "advanced"
 708                    destination cache will allow to solve this problem
 709                    --ANK (980726)
 710                  */
 711                 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
 712                         goto discard_it;
 713                 hdr = icmp6_hdr(skb);
 714                 orig_hdr = (struct ipv6hdr *) (hdr + 1);
 715                 rt6_pmtu_discovery(&orig_hdr->daddr, &orig_hdr->saddr, dev,
 716                                    ntohl(hdr->icmp6_mtu));
 717
 718                 /*
 719                  *      Drop through to notify
 720                  */
 721
 722         case ICMPV6_DEST_UNREACH:
 723         case ICMPV6_TIME_EXCEED:
 724         case ICMPV6_PARAMPROB:
 725                 icmpv6_notify(skb, type, hdr->icmp6_code, hdr->icmp6_mtu);
 726                 break;
 727
 728         case NDISC_ROUTER_SOLICITATION:
 729         case NDISC_ROUTER_ADVERTISEMENT:
 730         case NDISC_NEIGHBOUR_SOLICITATION:
 731         case NDISC_NEIGHBOUR_ADVERTISEMENT:
 732         case NDISC_REDIRECT:
 733                 ndisc_rcv(skb);
 734                 break;
 735
 736         case ICMPV6_MGM_QUERY:
 737                 igmp6_event_query(skb);
 738                 break;
 739
 740         case ICMPV6_MGM_REPORT:
 741                 igmp6_event_report(skb);
 742                 break;
 743
 744         case ICMPV6_MGM_REDUCTION:
 745         case ICMPV6_NI_QUERY:
 746         case ICMPV6_NI_REPLY:
 747         case ICMPV6_MLD2_REPORT:
 748         case ICMPV6_DHAAD_REQUEST:
 749         case ICMPV6_DHAAD_REPLY:
 750         case ICMPV6_MOBILE_PREFIX_SOL:
 751         case ICMPV6_MOBILE_PREFIX_ADV:
 752                 break;
 753
 754         default:
 755                 LIMIT_NETDEBUG(KERN_DEBUG "icmpv6: msg of unknown type\n");
 756
 757                 /* informational */
 758                 if (type & ICMPV6_INFOMSG_MASK)
 759                         break;
 760
 761                 /*
 762                  * error of unknown type.
 763                  * must pass to upper level
 764                  */
 765
 766                 icmpv6_notify(skb, type, hdr->icmp6_code, hdr->icmp6_mtu);
 767         }
 768
 769         kfree_skb(skb);
 770         return 0;
 771
 772 discard_it:
 773         ICMP6_INC_STATS_BH(idev, ICMP6_MIB_INERRORS);
 774 drop_no_count:
 775         kfree_skb(skb);
 776         return 0;
 777 }
 778
 779 void icmpv6_flow_init(struct sock *sk, struct flowi *fl,
 780                       u8 type,
 781                       const struct in6_addr *saddr,
 782                       const struct in6_addr *daddr,
 783                       int oif)
 784 {
 785         memset(fl, 0, sizeof(*fl));
 786         ipv6_addr_copy(&fl->fl6_src, saddr);
 787         ipv6_addr_copy(&fl->fl6_dst, daddr);
 788         fl->proto               = IPPROTO_ICMPV6;
 789         fl->fl_icmp_type        = type;
 790         fl->fl_icmp_code        = 0;
 791         fl->oif                 = oif;
 792         security_sk_classify_flow(sk, fl);
 793 }
 794
 795 /*
 796  * Special lock-class for __icmpv6_sk:
 797  */
 798 static struct lock_class_key icmpv6_socket_sk_dst_lock_key;
 799
 800 static int __net_init icmpv6_sk_init(struct net *net)
 801 {
 802         struct sock *sk;
 803         int err, i, j;
 804
 805         net->ipv6.icmp_sk =
 806                 kzalloc(nr_cpu_ids * sizeof(struct sock *), GFP_KERNEL);
 807         if (net->ipv6.icmp_sk == NULL)
 808                 return -ENOMEM;
 809
 810         for_each_possible_cpu(i) {
 811                 struct socket *sock;
 812                 err = sock_create_kern(PF_INET6, SOCK_RAW, IPPROTO_ICMPV6,
 813                                        &sock);
 814                 if (err < 0) {
 815                         printk(KERN_ERR
 816                                "Failed to initialize the ICMP6 control socket "
 817                                "(err %d).\n",
 818                                err);
 819                         goto fail;
 820                 }
 821
 822                 net->ipv6.icmp_sk[i] = sk = sock->sk;
 823                 sk_change_net(sk, net);
 824
 825                 sk->sk_allocation = GFP_ATOMIC;
 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                 sk->sk_prot->unhash(sk);
 842         }
 843         return 0;
 844
 845  fail:
 846         for (j = 0; j < i; j++)
 847                 sk_release_kernel(net->ipv6.icmp_sk[j]);
 848         kfree(net->ipv6.icmp_sk);
 849         return err;
 850 }
 851
 852 static void __net_exit icmpv6_sk_exit(struct net *net)
 853 {
 854         int i;
 855
 856         for_each_possible_cpu(i) {
 857                 sk_release_kernel(net->ipv6.icmp_sk[i]);
 858         }
 859         kfree(net->ipv6.icmp_sk);
 860 }
 861
 862 static struct pernet_operations icmpv6_sk_ops = {
 863        .init = icmpv6_sk_init,
 864        .exit = icmpv6_sk_exit,
 865 };
 866
 867 int __init icmpv6_init(void)
 868 {
 869         int err;
 870
 871         err = register_pernet_subsys(&icmpv6_sk_ops);
 872         if (err < 0)
 873                 return err;
 874
 875         err = -EAGAIN;
 876         if (inet6_add_protocol(&icmpv6_protocol, IPPROTO_ICMPV6) < 0)
 877                 goto fail;
 878         return 0;
 879
 880 fail:
 881         printk(KERN_ERR "Failed to register ICMP6 protocol\n");
 882         unregister_pernet_subsys(&icmpv6_sk_ops);
 883         return err;
 884 }
 885
 886 void icmpv6_cleanup(void)
 887 {
 888         unregister_pernet_subsys(&icmpv6_sk_ops);
 889         inet6_del_protocol(&icmpv6_protocol, IPPROTO_ICMPV6);
 890 }
 891
 892
 893 static const struct icmp6_err {
 894         int err;
 895         int fatal;
 896 } tab_unreach[] = {
 897         {       /* NOROUTE */
 898                 .err    = ENETUNREACH,
 899                 .fatal  = 0,
 900         },
 901         {       /* ADM_PROHIBITED */
 902                 .err    = EACCES,
 903                 .fatal  = 1,
 904         },
 905         {       /* Was NOT_NEIGHBOUR, now reserved */
 906                 .err    = EHOSTUNREACH,
 907                 .fatal  = 0,
 908         },
 909         {       /* ADDR_UNREACH */
 910                 .err    = EHOSTUNREACH,
 911                 .fatal  = 0,
 912         },
 913         {       /* PORT_UNREACH */
 914                 .err    = ECONNREFUSED,
 915                 .fatal  = 1,
 916         },
 917 };
 918
 919 int icmpv6_err_convert(int type, int code, int *err)
 920 {
 921         int fatal = 0;
 922
 923         *err = EPROTO;
 924
 925         switch (type) {
 926         case ICMPV6_DEST_UNREACH:
 927                 fatal = 1;
 928                 if (code <= ICMPV6_PORT_UNREACH) {
 929                         *err  = tab_unreach[code].err;
 930                         fatal = tab_unreach[code].fatal;
 931                 }
 932                 break;
 933
 934         case ICMPV6_PKT_TOOBIG:
 935                 *err = EMSGSIZE;
 936                 break;
 937
 938         case ICMPV6_PARAMPROB:
 939                 *err = EPROTO;
 940                 fatal = 1;
 941                 break;
 942
 943         case ICMPV6_TIME_EXCEED:
 944                 *err = EHOSTUNREACH;
 945                 break;
 946         }
 947
 948         return fatal;
 949 }
 950
 951 EXPORT_SYMBOL(icmpv6_err_convert);
 952
 953 #ifdef CONFIG_SYSCTL
 954 ctl_table ipv6_icmp_table_template[] = {
 955         {
 956                 .ctl_name       = NET_IPV6_ICMP_RATELIMIT,
 957                 .procname       = "ratelimit",
 958                 .data           = &init_net.ipv6.sysctl.icmpv6_time,
 959                 .maxlen         = sizeof(int),
 960                 .mode           = 0644,
 961                 .proc_handler   = &proc_dointvec
 962         },
 963         { .ctl_name = 0 },
 964 };
 965
 966 struct ctl_table *ipv6_icmp_sysctl_init(struct net *net)
 967 {
 968         struct ctl_table *table;
 969
 970         table = kmemdup(ipv6_icmp_table_template,
 971                         sizeof(ipv6_icmp_table_template),
 972                         GFP_KERNEL);
 973
 974         if (table)
 975                 table[0].data = &net->ipv6.sysctl.icmpv6_time;
 976
 977         return table;
 978 }
 979 #endif
 980