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
  70 /*
  71  *      The ICMP socket(s). This is the most convenient way to flow control
  72  *      our ICMP output as well as maintain a clean interface throughout
  73  *      all layers. All Socketless IP sends will soon be gone.
  74  *
  75  *      On SMP we have one ICMP socket per-cpu.
  76  */
  77 static inline struct sock *icmpv6_sk(struct net *net)
  78 {
  79         return net->ipv6.icmp_sk[smp_processor_id()];
  80 }
  81
  82 static int icmpv6_rcv(struct sk_buff *skb);
  83
  84 static const struct inet6_protocol icmpv6_protocol = {
  85         .handler        =       icmpv6_rcv,
  86         .flags          =       INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
  87 };
  88
  89 static __inline__ struct sock *icmpv6_xmit_lock(struct net *net)
  90 {
  91         struct sock *sk;
  92
  93         local_bh_disable();
  94
  95         sk = icmpv6_sk(net);
  96         if (unlikely(!spin_trylock(&sk->sk_lock.slock))) {
  97                 /* This can happen if the output path (f.e. SIT or
  98                  * ip6ip6 tunnel) signals dst_link_failure() for an
  99                  * outgoing ICMP6 packet.
 100                  */
 101                 local_bh_enable();
 102                 return NULL;
 103         }
 104         return sk;
 105 }
 106
 107 static __inline__ void icmpv6_xmit_unlock(struct sock *sk)
 108 {
 109         spin_unlock_bh(&sk->sk_lock.slock);
 110 }
 111
 112 /*
 113  * Slightly more convenient version of icmpv6_send.
 114  */
 115 void icmpv6_param_prob(struct sk_buff *skb, u8 code, int pos)
 116 {
 117         icmpv6_send(skb, ICMPV6_PARAMPROB, code, pos);
 118         kfree_skb(skb);
 119 }
 120
 121 /*
 122  * Figure out, may we reply to this packet with icmp error.
 123  *
 124  * We do not reply, if:
 125  *      - it was icmp error message.
 126  *      - it is truncated, so that it is known, that protocol is ICMPV6
 127  *        (i.e. in the middle of some exthdr)
 128  *
 129  *      --ANK (980726)
 130  */
 131
 132 static int is_ineligible(struct sk_buff *skb)
 133 {
 134         int ptr = (u8 *)(ipv6_hdr(skb) + 1) - skb->data;
 135         int len = skb->len - ptr;
 136         __u8 nexthdr = ipv6_hdr(skb)->nexthdr;
 137         __be16 frag_off;
 138
 139         if (len < 0)
 140                 return 1;
 141
 142         ptr = ipv6_skip_exthdr(skb, ptr, &nexthdr, &frag_off);
 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                         tmp = iph->saddr;
 294                         iph->saddr = hao->addr;
 295                         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         fl6.daddr = hdr->saddr;
 448         if (saddr)
 449                 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         else if (!fl6.flowi6_oif)
 471                 fl6.flowi6_oif = np->ucast_oif;
 472
 473         dst = icmpv6_route_lookup(net, skb, sk, &fl6);
 474         if (IS_ERR(dst))
 475                 goto out;
 476
 477         if (ipv6_addr_is_multicast(&fl6.daddr))
 478                 hlimit = np->mcast_hops;
 479         else
 480                 hlimit = np->hop_limit;
 481         if (hlimit < 0)
 482                 hlimit = ip6_dst_hoplimit(dst);
 483
 484         msg.skb = skb;
 485         msg.offset = skb_network_offset(skb);
 486         msg.type = type;
 487
 488         len = skb->len - msg.offset;
 489         len = min_t(unsigned int, len, IPV6_MIN_MTU - sizeof(struct ipv6hdr) -sizeof(struct icmp6hdr));
 490         if (len < 0) {
 491                 LIMIT_NETDEBUG(KERN_DEBUG "icmp: len problem\n");
 492                 goto out_dst_release;
 493         }
 494
 495         rcu_read_lock();
 496         idev = __in6_dev_get(skb->dev);
 497
 498         err = ip6_append_data(sk, icmpv6_getfrag, &msg,
 499                               len + sizeof(struct icmp6hdr),
 500                               sizeof(struct icmp6hdr), hlimit,
 501                               np->tclass, NULL, &fl6, (struct rt6_info *)dst,
 502                               MSG_DONTWAIT, np->dontfrag);
 503         if (err) {
 504                 ICMP6_INC_STATS_BH(net, idev, ICMP6_MIB_OUTERRORS);
 505                 ip6_flush_pending_frames(sk);
 506         } else {
 507                 err = icmpv6_push_pending_frames(sk, &fl6, &tmp_hdr,
 508                                                  len + sizeof(struct icmp6hdr));
 509         }
 510         rcu_read_unlock();
 511 out_dst_release:
 512         dst_release(dst);
 513 out:
 514         icmpv6_xmit_unlock(sk);
 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         fl6.daddr = ipv6_hdr(skb)->saddr;
 544         if (saddr)
 545                 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         else if (!fl6.flowi6_oif)
 558                 fl6.flowi6_oif = np->ucast_oif;
 559
 560         err = ip6_dst_lookup(sk, &dst, &fl6);
 561         if (err)
 562                 goto out;
 563         dst = xfrm_lookup(net, dst, flowi6_to_flowi(&fl6), sk, 0);
 564         if (IS_ERR(dst))
 565                 goto out;
 566
 567         if (ipv6_addr_is_multicast(&fl6.daddr))
 568                 hlimit = np->mcast_hops;
 569         else
 570                 hlimit = np->hop_limit;
 571         if (hlimit < 0)
 572                 hlimit = ip6_dst_hoplimit(dst);
 573
 574         idev = __in6_dev_get(skb->dev);
 575
 576         msg.skb = skb;
 577         msg.offset = 0;
 578         msg.type = ICMPV6_ECHO_REPLY;
 579
 580         err = ip6_append_data(sk, icmpv6_getfrag, &msg, skb->len + sizeof(struct icmp6hdr),
 581                                 sizeof(struct icmp6hdr), hlimit, np->tclass, NULL, &fl6,
 582                                 (struct rt6_info *)dst, MSG_DONTWAIT,
 583                                 np->dontfrag);
 584
 585         if (err) {
 586                 ICMP6_INC_STATS_BH(net, idev, ICMP6_MIB_OUTERRORS);
 587                 ip6_flush_pending_frames(sk);
 588         } else {
 589                 err = icmpv6_push_pending_frames(sk, &fl6, &tmp_hdr,
 590                                                  skb->len + sizeof(struct icmp6hdr));
 591         }
 592         dst_release(dst);
 593 out:
 594         icmpv6_xmit_unlock(sk);
 595 }
 596
 597 static void icmpv6_notify(struct sk_buff *skb, u8 type, u8 code, __be32 info)
 598 {
 599         const struct inet6_protocol *ipprot;
 600         int inner_offset;
 601         int hash;
 602         u8 nexthdr;
 603         __be16 frag_off;
 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),
 612                                                 &nexthdr, &frag_off);
 613                 if (inner_offset<0)
 614                         return;
 615         } else {
 616                 inner_offset = sizeof(struct ipv6hdr);
 617         }
 618
 619         /* Checkin header including 8 bytes of inner protocol header. */
 620         if (!pskb_may_pull(skb, inner_offset+8))
 621                 return;
 622
 623         /* BUGGG_FUTURE: we should try to parse exthdrs in this packet.
 624            Without this we will not able f.e. to make source routed
 625            pmtu discovery.
 626            Corresponding argument (opt) to notifiers is already added.
 627            --ANK (980726)
 628          */
 629
 630         hash = nexthdr & (MAX_INET_PROTOS - 1);
 631
 632         rcu_read_lock();
 633         ipprot = rcu_dereference(inet6_protos[hash]);
 634         if (ipprot && ipprot->err_handler)
 635                 ipprot->err_handler(skb, NULL, type, code, inner_offset, info);
 636         rcu_read_unlock();
 637
 638         raw6_icmp_error(skb, nexthdr, type, code, inner_offset, info);
 639 }
 640
 641 /*
 642  *      Handle icmp messages
 643  */
 644
 645 static int icmpv6_rcv(struct sk_buff *skb)
 646 {
 647         struct net_device *dev = skb->dev;
 648         struct inet6_dev *idev = __in6_dev_get(dev);
 649         const struct in6_addr *saddr, *daddr;
 650         const struct ipv6hdr *orig_hdr;
 651         struct icmp6hdr *hdr;
 652         u8 type;
 653
 654         if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
 655                 struct sec_path *sp = skb_sec_path(skb);
 656                 int nh;
 657
 658                 if (!(sp && sp->xvec[sp->len - 1]->props.flags &
 659                                  XFRM_STATE_ICMP))
 660                         goto drop_no_count;
 661
 662                 if (!pskb_may_pull(skb, sizeof(*hdr) + sizeof(*orig_hdr)))
 663                         goto drop_no_count;
 664
 665                 nh = skb_network_offset(skb);
 666                 skb_set_network_header(skb, sizeof(*hdr));
 667
 668                 if (!xfrm6_policy_check_reverse(NULL, XFRM_POLICY_IN, skb))
 669                         goto drop_no_count;
 670
 671                 skb_set_network_header(skb, nh);
 672         }
 673
 674         ICMP6_INC_STATS_BH(dev_net(dev), idev, ICMP6_MIB_INMSGS);
 675
 676         saddr = &ipv6_hdr(skb)->saddr;
 677         daddr = &ipv6_hdr(skb)->daddr;
 678
 679         /* Perform checksum. */
 680         switch (skb->ip_summed) {
 681         case CHECKSUM_COMPLETE:
 682                 if (!csum_ipv6_magic(saddr, daddr, skb->len, IPPROTO_ICMPV6,
 683                                      skb->csum))
 684                         break;
 685                 /* fall through */
 686         case CHECKSUM_NONE:
 687                 skb->csum = ~csum_unfold(csum_ipv6_magic(saddr, daddr, skb->len,
 688                                              IPPROTO_ICMPV6, 0));
 689                 if (__skb_checksum_complete(skb)) {
 690                         LIMIT_NETDEBUG(KERN_DEBUG "ICMPv6 checksum failed [%pI6 > %pI6]\n",
 691                                        saddr, daddr);
 692                         goto discard_it;
 693                 }
 694         }
 695
 696         if (!pskb_pull(skb, sizeof(*hdr)))
 697                 goto discard_it;
 698
 699         hdr = icmp6_hdr(skb);
 700
 701         type = hdr->icmp6_type;
 702
 703         ICMP6MSGIN_INC_STATS_BH(dev_net(dev), idev, type);
 704
 705         switch (type) {
 706         case ICMPV6_ECHO_REQUEST:
 707                 icmpv6_echo_reply(skb);
 708                 break;
 709
 710         case ICMPV6_ECHO_REPLY:
 711                 /* we couldn't care less */
 712                 break;
 713
 714         case ICMPV6_PKT_TOOBIG:
 715                 /* BUGGG_FUTURE: if packet contains rthdr, we cannot update
 716                    standard destination cache. Seems, only "advanced"
 717                    destination cache will allow to solve this problem
 718                    --ANK (980726)
 719                  */
 720                 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
 721                         goto discard_it;
 722                 hdr = icmp6_hdr(skb);
 723                 orig_hdr = (struct ipv6hdr *) (hdr + 1);
 724                 rt6_pmtu_discovery(&orig_hdr->daddr, &orig_hdr->saddr, dev,
 725                                    ntohl(hdr->icmp6_mtu));
 726
 727                 /*
 728                  *      Drop through to notify
 729                  */
 730
 731         case ICMPV6_DEST_UNREACH:
 732         case ICMPV6_TIME_EXCEED:
 733         case ICMPV6_PARAMPROB:
 734                 icmpv6_notify(skb, type, hdr->icmp6_code, hdr->icmp6_mtu);
 735                 break;
 736
 737         case NDISC_ROUTER_SOLICITATION:
 738         case NDISC_ROUTER_ADVERTISEMENT:
 739         case NDISC_NEIGHBOUR_SOLICITATION:
 740         case NDISC_NEIGHBOUR_ADVERTISEMENT:
 741         case NDISC_REDIRECT:
 742                 ndisc_rcv(skb);
 743                 break;
 744
 745         case ICMPV6_MGM_QUERY:
 746                 igmp6_event_query(skb);
 747                 break;
 748
 749         case ICMPV6_MGM_REPORT:
 750                 igmp6_event_report(skb);
 751                 break;
 752
 753         case ICMPV6_MGM_REDUCTION:
 754         case ICMPV6_NI_QUERY:
 755         case ICMPV6_NI_REPLY:
 756         case ICMPV6_MLD2_REPORT:
 757         case ICMPV6_DHAAD_REQUEST:
 758         case ICMPV6_DHAAD_REPLY:
 759         case ICMPV6_MOBILE_PREFIX_SOL:
 760         case ICMPV6_MOBILE_PREFIX_ADV:
 761                 break;
 762
 763         default:
 764                 LIMIT_NETDEBUG(KERN_DEBUG "icmpv6: msg of unknown type\n");
 765
 766                 /* informational */
 767                 if (type & ICMPV6_INFOMSG_MASK)
 768                         break;
 769
 770                 /*
 771                  * error of unknown type.
 772                  * must pass to upper level
 773                  */
 774
 775                 icmpv6_notify(skb, type, hdr->icmp6_code, hdr->icmp6_mtu);
 776         }
 777
 778         kfree_skb(skb);
 779         return 0;
 780
 781 discard_it:
 782         ICMP6_INC_STATS_BH(dev_net(dev), idev, ICMP6_MIB_INERRORS);
 783 drop_no_count:
 784         kfree_skb(skb);
 785         return 0;
 786 }
 787
 788 void icmpv6_flow_init(struct sock *sk, struct flowi6 *fl6,
 789                       u8 type,
 790                       const struct in6_addr *saddr,
 791                       const struct in6_addr *daddr,
 792                       int oif)
 793 {
 794         memset(fl6, 0, sizeof(*fl6));
 795         fl6->saddr = *saddr;
 796         fl6->daddr = *daddr;
 797         fl6->flowi6_proto       = IPPROTO_ICMPV6;
 798         fl6->fl6_icmp_type      = type;
 799         fl6->fl6_icmp_code      = 0;
 800         fl6->flowi6_oif         = oif;
 801         security_sk_classify_flow(sk, flowi6_to_flowi(fl6));
 802 }
 803
 804 /*
 805  * Special lock-class for __icmpv6_sk:
 806  */
 807 static struct lock_class_key icmpv6_socket_sk_dst_lock_key;
 808
 809 static int __net_init icmpv6_sk_init(struct net *net)
 810 {
 811         struct sock *sk;
 812         int err, i, j;
 813
 814         net->ipv6.icmp_sk =
 815                 kzalloc(nr_cpu_ids * sizeof(struct sock *), GFP_KERNEL);
 816         if (net->ipv6.icmp_sk == NULL)
 817                 return -ENOMEM;
 818
 819         for_each_possible_cpu(i) {
 820                 err = inet_ctl_sock_create(&sk, PF_INET6,
 821                                            SOCK_RAW, IPPROTO_ICMPV6, net);
 822                 if (err < 0) {
 823                         printk(KERN_ERR
 824                                "Failed to initialize the ICMP6 control socket "
 825                                "(err %d).\n",
 826                                err);
 827                         goto fail;
 828                 }
 829
 830                 net->ipv6.icmp_sk[i] = sk;
 831
 832                 /*
 833                  * Split off their lock-class, because sk->sk_dst_lock
 834                  * gets used from softirqs, which is safe for
 835                  * __icmpv6_sk (because those never get directly used
 836                  * via userspace syscalls), but unsafe for normal sockets.
 837                  */
 838                 lockdep_set_class(&sk->sk_dst_lock,
 839                                   &icmpv6_socket_sk_dst_lock_key);
 840
 841                 /* Enough space for 2 64K ICMP packets, including
 842                  * sk_buff struct overhead.
 843                  */
 844                 sk->sk_sndbuf = 2 * SKB_TRUESIZE(64 * 1024);
 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 EXPORT_SYMBOL(icmpv6_err_convert);
 954
 955 #ifdef CONFIG_SYSCTL
 956 ctl_table ipv6_icmp_table_template[] = {
 957         {
 958                 .procname       = "ratelimit",
 959                 .data           = &init_net.ipv6.sysctl.icmpv6_time,
 960                 .maxlen         = sizeof(int),
 961                 .mode           = 0644,
 962                 .proc_handler   = proc_dointvec_ms_jiffies,
 963         },
 964         { },
 965 };
 966
 967 struct ctl_table * __net_init ipv6_icmp_sysctl_init(struct net *net)
 968 {
 969         struct ctl_table *table;
 970
 971         table = kmemdup(ipv6_icmp_table_template,
 972                         sizeof(ipv6_icmp_table_template),
 973                         GFP_KERNEL);
 974
 975         if (table)
 976                 table[0].data = &net->ipv6.sysctl.icmpv6_time;
 977
 978         return table;
 979 }
 980 #endif
 981