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((char *)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((char *)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(&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(&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(&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                 int nh;
 650
 651                 if (!(skb->sp && skb->sp->xvec[skb->sp->len - 1]->props.flags &
 652                                  XFRM_STATE_ICMP))
 653                         goto drop_no_count;
 654
 655                 if (!pskb_may_pull(skb, sizeof(*hdr) + sizeof(*orig_hdr)))
 656                         goto drop_no_count;
 657
 658                 nh = skb_network_offset(skb);
 659                 skb_set_network_header(skb, sizeof(*hdr));
 660
 661                 if (!xfrm6_policy_check_reverse(NULL, XFRM_POLICY_IN, skb))
 662                         goto drop_no_count;
 663
 664                 skb_set_network_header(skb, nh);
 665         }
 666
 667         ICMP6_INC_STATS_BH(dev_net(dev), idev, ICMP6_MIB_INMSGS);
 668
 669         saddr = &ipv6_hdr(skb)->saddr;
 670         daddr = &ipv6_hdr(skb)->daddr;
 671
 672         /* Perform checksum. */
 673         switch (skb->ip_summed) {
 674         case CHECKSUM_COMPLETE:
 675                 if (!csum_ipv6_magic(saddr, daddr, skb->len, IPPROTO_ICMPV6,
 676                                      skb->csum))
 677                         break;
 678                 /* fall through */
 679         case CHECKSUM_NONE:
 680                 skb->csum = ~csum_unfold(csum_ipv6_magic(saddr, daddr, skb->len,
 681                                              IPPROTO_ICMPV6, 0));
 682                 if (__skb_checksum_complete(skb)) {
 683                         LIMIT_NETDEBUG(KERN_DEBUG "ICMPv6 checksum failed [" NIP6_FMT " > " NIP6_FMT "]\n",
 684                                        NIP6(*saddr), NIP6(*daddr));
 685                         goto discard_it;
 686                 }
 687         }
 688
 689         if (!pskb_pull(skb, sizeof(*hdr)))
 690                 goto discard_it;
 691
 692         hdr = icmp6_hdr(skb);
 693
 694         type = hdr->icmp6_type;
 695
 696         ICMP6MSGIN_INC_STATS_BH(dev_net(dev), idev, type);
 697
 698         switch (type) {
 699         case ICMPV6_ECHO_REQUEST:
 700                 icmpv6_echo_reply(skb);
 701                 break;
 702
 703         case ICMPV6_ECHO_REPLY:
 704                 /* we couldn't care less */
 705                 break;
 706
 707         case ICMPV6_PKT_TOOBIG:
 708                 /* BUGGG_FUTURE: if packet contains rthdr, we cannot update
 709                    standard destination cache. Seems, only "advanced"
 710                    destination cache will allow to solve this problem
 711                    --ANK (980726)
 712                  */
 713                 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
 714                         goto discard_it;
 715                 hdr = icmp6_hdr(skb);
 716                 orig_hdr = (struct ipv6hdr *) (hdr + 1);
 717                 rt6_pmtu_discovery(&orig_hdr->daddr, &orig_hdr->saddr, dev,
 718                                    ntohl(hdr->icmp6_mtu));
 719
 720                 /*
 721                  *      Drop through to notify
 722                  */
 723
 724         case ICMPV6_DEST_UNREACH:
 725         case ICMPV6_TIME_EXCEED:
 726         case ICMPV6_PARAMPROB:
 727                 icmpv6_notify(skb, type, hdr->icmp6_code, hdr->icmp6_mtu);
 728                 break;
 729
 730         case NDISC_ROUTER_SOLICITATION:
 731         case NDISC_ROUTER_ADVERTISEMENT:
 732         case NDISC_NEIGHBOUR_SOLICITATION:
 733         case NDISC_NEIGHBOUR_ADVERTISEMENT:
 734         case NDISC_REDIRECT:
 735                 ndisc_rcv(skb);
 736                 break;
 737
 738         case ICMPV6_MGM_QUERY:
 739                 igmp6_event_query(skb);
 740                 break;
 741
 742         case ICMPV6_MGM_REPORT:
 743                 igmp6_event_report(skb);
 744                 break;
 745
 746         case ICMPV6_MGM_REDUCTION:
 747         case ICMPV6_NI_QUERY:
 748         case ICMPV6_NI_REPLY:
 749         case ICMPV6_MLD2_REPORT:
 750         case ICMPV6_DHAAD_REQUEST:
 751         case ICMPV6_DHAAD_REPLY:
 752         case ICMPV6_MOBILE_PREFIX_SOL:
 753         case ICMPV6_MOBILE_PREFIX_ADV:
 754                 break;
 755
 756         default:
 757                 LIMIT_NETDEBUG(KERN_DEBUG "icmpv6: msg of unknown type\n");
 758
 759                 /* informational */
 760                 if (type & ICMPV6_INFOMSG_MASK)
 761                         break;
 762
 763                 /*
 764                  * error of unknown type.
 765                  * must pass to upper level
 766                  */
 767
 768                 icmpv6_notify(skb, type, hdr->icmp6_code, hdr->icmp6_mtu);
 769         }
 770
 771         kfree_skb(skb);
 772         return 0;
 773
 774 discard_it:
 775         ICMP6_INC_STATS_BH(dev_net(dev), idev, ICMP6_MIB_INERRORS);
 776 drop_no_count:
 777         kfree_skb(skb);
 778         return 0;
 779 }
 780
 781 void icmpv6_flow_init(struct sock *sk, struct flowi *fl,
 782                       u8 type,
 783                       const struct in6_addr *saddr,
 784                       const struct in6_addr *daddr,
 785                       int oif)
 786 {
 787         memset(fl, 0, sizeof(*fl));
 788         ipv6_addr_copy(&fl->fl6_src, saddr);
 789         ipv6_addr_copy(&fl->fl6_dst, daddr);
 790         fl->proto               = IPPROTO_ICMPV6;
 791         fl->fl_icmp_type        = type;
 792         fl->fl_icmp_code        = 0;
 793         fl->oif                 = oif;
 794         security_sk_classify_flow(sk, fl);
 795 }
 796
 797 /*
 798  * Special lock-class for __icmpv6_sk:
 799  */
 800 static struct lock_class_key icmpv6_socket_sk_dst_lock_key;
 801
 802 static int __net_init icmpv6_sk_init(struct net *net)
 803 {
 804         struct sock *sk;
 805         int err, i, j;
 806
 807         net->ipv6.icmp_sk =
 808                 kzalloc(nr_cpu_ids * sizeof(struct sock *), GFP_KERNEL);
 809         if (net->ipv6.icmp_sk == NULL)
 810                 return -ENOMEM;
 811
 812         for_each_possible_cpu(i) {
 813                 err = inet_ctl_sock_create(&sk, PF_INET6,
 814                                            SOCK_RAW, IPPROTO_ICMPV6, net);
 815                 if (err < 0) {
 816                         printk(KERN_ERR
 817                                "Failed to initialize the ICMP6 control socket "
 818                                "(err %d).\n",
 819                                err);
 820                         goto fail;
 821                 }
 822
 823                 net->ipv6.icmp_sk[i] = sk;
 824
 825                 /*
 826                  * Split off their lock-class, because sk->sk_dst_lock
 827                  * gets used from softirqs, which is safe for
 828                  * __icmpv6_sk (because those never get directly used
 829                  * via userspace syscalls), but unsafe for normal sockets.
 830                  */
 831                 lockdep_set_class(&sk->sk_dst_lock,
 832                                   &icmpv6_socket_sk_dst_lock_key);
 833
 834                 /* Enough space for 2 64K ICMP packets, including
 835                  * sk_buff struct overhead.
 836                  */
 837                 sk->sk_sndbuf =
 838                         (2 * ((64 * 1024) + sizeof(struct sk_buff)));
 839         }
 840         return 0;
 841
 842  fail:
 843         for (j = 0; j < i; j++)
 844                 inet_ctl_sock_destroy(net->ipv6.icmp_sk[j]);
 845         kfree(net->ipv6.icmp_sk);
 846         return err;
 847 }
 848
 849 static void __net_exit icmpv6_sk_exit(struct net *net)
 850 {
 851         int i;
 852
 853         for_each_possible_cpu(i) {
 854                 inet_ctl_sock_destroy(net->ipv6.icmp_sk[i]);
 855         }
 856         kfree(net->ipv6.icmp_sk);
 857 }
 858
 859 static struct pernet_operations icmpv6_sk_ops = {
 860        .init = icmpv6_sk_init,
 861        .exit = icmpv6_sk_exit,
 862 };
 863
 864 int __init icmpv6_init(void)
 865 {
 866         int err;
 867
 868         err = register_pernet_subsys(&icmpv6_sk_ops);
 869         if (err < 0)
 870                 return err;
 871
 872         err = -EAGAIN;
 873         if (inet6_add_protocol(&icmpv6_protocol, IPPROTO_ICMPV6) < 0)
 874                 goto fail;
 875         return 0;
 876
 877 fail:
 878         printk(KERN_ERR "Failed to register ICMP6 protocol\n");
 879         unregister_pernet_subsys(&icmpv6_sk_ops);
 880         return err;
 881 }
 882
 883 void icmpv6_cleanup(void)
 884 {
 885         unregister_pernet_subsys(&icmpv6_sk_ops);
 886         inet6_del_protocol(&icmpv6_protocol, IPPROTO_ICMPV6);
 887 }
 888
 889
 890 static const struct icmp6_err {
 891         int err;
 892         int fatal;
 893 } tab_unreach[] = {
 894         {       /* NOROUTE */
 895                 .err    = ENETUNREACH,
 896                 .fatal  = 0,
 897         },
 898         {       /* ADM_PROHIBITED */
 899                 .err    = EACCES,
 900                 .fatal  = 1,
 901         },
 902         {       /* Was NOT_NEIGHBOUR, now reserved */
 903                 .err    = EHOSTUNREACH,
 904                 .fatal  = 0,
 905         },
 906         {       /* ADDR_UNREACH */
 907                 .err    = EHOSTUNREACH,
 908                 .fatal  = 0,
 909         },
 910         {       /* PORT_UNREACH */
 911                 .err    = ECONNREFUSED,
 912                 .fatal  = 1,
 913         },
 914 };
 915
 916 int icmpv6_err_convert(int type, int code, int *err)
 917 {
 918         int fatal = 0;
 919
 920         *err = EPROTO;
 921
 922         switch (type) {
 923         case ICMPV6_DEST_UNREACH:
 924                 fatal = 1;
 925                 if (code <= ICMPV6_PORT_UNREACH) {
 926                         *err  = tab_unreach[code].err;
 927                         fatal = tab_unreach[code].fatal;
 928                 }
 929                 break;
 930
 931         case ICMPV6_PKT_TOOBIG:
 932                 *err = EMSGSIZE;
 933                 break;
 934
 935         case ICMPV6_PARAMPROB:
 936                 *err = EPROTO;
 937                 fatal = 1;
 938                 break;
 939
 940         case ICMPV6_TIME_EXCEED:
 941                 *err = EHOSTUNREACH;
 942                 break;
 943         }
 944
 945         return fatal;
 946 }
 947
 948 EXPORT_SYMBOL(icmpv6_err_convert);
 949
 950 #ifdef CONFIG_SYSCTL
 951 ctl_table ipv6_icmp_table_template[] = {
 952         {
 953                 .ctl_name       = NET_IPV6_ICMP_RATELIMIT,
 954                 .procname       = "ratelimit",
 955                 .data           = &init_net.ipv6.sysctl.icmpv6_time,
 956                 .maxlen         = sizeof(int),
 957                 .mode           = 0644,
 958                 .proc_handler   = &proc_dointvec_ms_jiffies,
 959                 .strategy       = &sysctl_ms_jiffies
 960         },
 961         { .ctl_name = 0 },
 962 };
 963
 964 struct ctl_table *ipv6_icmp_sysctl_init(struct net *net)
 965 {
 966         struct ctl_table *table;
 967
 968         table = kmemdup(ipv6_icmp_table_template,
 969                         sizeof(ipv6_icmp_table_template),
 970                         GFP_KERNEL);
 971
 972         if (table)
 973                 table[0].data = &net->ipv6.sysctl.icmpv6_time;
 974
 975         return table;
 976 }
 977 #endif
 978