net/ipv6/icmp.c

   1 /*
   2  *      Internet Control Message Protocol (ICMPv6)
   3  *      Linux INET6 implementation
   4  *
   5  *      Authors:
   6  *      Pedro Roque             <roque@di.fc.ul.pt>
   7  *
   8  *      Based on net/ipv4/icmp.c
   9  *
  10  *      RFC 1885
  11  *
  12  *      This program is free software; you can redistribute it and/or
  13  *      modify it under the terms of the GNU General Public License
  14  *      as published by the Free Software Foundation; either version
  15  *      2 of the License, or (at your option) any later version.
  16  */
  17
  18 /*
  19  *      Changes:
  20  *
  21  *      Andi Kleen              :       exception handling
  22  *      Andi Kleen                      add rate limits. never reply to a icmp.
  23  *                                      add more length checks and other fixes.
  24  *      yoshfuji                :       ensure to sent parameter problem for
  25  *                                      fragments.
  26  *      YOSHIFUJI Hideaki @USAGI:       added sysctl for icmp rate limit.
  27  *      Randy Dunlap and
  28  *      YOSHIFUJI Hideaki @USAGI:       Per-interface statistics support
  29  *      Kazunori MIYAZAWA @USAGI:       change output process to use ip6_append_data
  30  */
  31
  32 #include <linux/module.h>
  33 #include <linux/errno.h>
  34 #include <linux/types.h>
  35 #include <linux/socket.h>
  36 #include <linux/in.h>
  37 #include <linux/kernel.h>
  38 #include <linux/sockios.h>
  39 #include <linux/net.h>
  40 #include <linux/skbuff.h>
  41 #include <linux/init.h>
  42 #include <linux/netfilter.h>
  43 #include <linux/slab.h>
  44
  45 #ifdef CONFIG_SYSCTL
  46 #include <linux/sysctl.h>
  47 #endif
  48
  49 #include <linux/inet.h>
  50 #include <linux/netdevice.h>
  51 #include <linux/icmpv6.h>
  52
  53 #include <net/ip.h>
  54 #include <net/sock.h>
  55
  56 #include <net/ipv6.h>
  57 #include <net/ip6_checksum.h>
  58 #include <net/protocol.h>
  59 #include <net/raw.h>
  60 #include <net/rawv6.h>
  61 #include <net/transp_v6.h>
  62 #include <net/ip6_route.h>
  63 #include <net/addrconf.h>
  64 #include <net/icmp.h>
  65 #include <net/xfrm.h>
  66 #include <net/inet_common.h>
  67
  68 #include <asm/uaccess.h>
  69 #include <asm/system.h>
  70
  71 /*
  72  *      The ICMP socket(s). This is the most convenient way to flow control
  73  *      our ICMP output as well as maintain a clean interface throughout
  74  *      all layers. All Socketless IP sends will soon be gone.
  75  *
  76  *      On SMP we have one ICMP socket per-cpu.
  77  */
  78 static inline struct sock *icmpv6_sk(struct net *net)
  79 {
  80         return net->ipv6.icmp_sk[smp_processor_id()];
  81 }
  82
  83 static int icmpv6_rcv(struct sk_buff *skb);
  84
  85 static const struct inet6_protocol icmpv6_protocol = {
  86         .handler        =       icmpv6_rcv,
  87         .flags          =       INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
  88 };
  89
  90 static __inline__ struct sock *icmpv6_xmit_lock(struct net *net)
  91 {
  92         struct sock *sk;
  93
  94         local_bh_disable();
  95
  96         sk = icmpv6_sk(net);
  97         if (unlikely(!spin_trylock(&sk->sk_lock.slock))) {
  98                 /* This can happen if the output path (f.e. SIT or
  99                  * ip6ip6 tunnel) signals dst_link_failure() for an
 100                  * outgoing ICMP6 packet.
 101                  */
 102                 local_bh_enable();
 103                 return NULL;
 104         }
 105         return sk;
 106 }
 107
 108 static __inline__ void icmpv6_xmit_unlock(struct sock *sk)
 109 {
 110         spin_unlock_bh(&sk->sk_lock.slock);
 111 }
 112
 113 /*
 114  * Slightly more convenient version of icmpv6_send.
 115  */
 116 void icmpv6_param_prob(struct sk_buff *skb, u8 code, int pos)
 117 {
 118         icmpv6_send(skb, ICMPV6_PARAMPROB, code, pos);
 119         kfree_skb(skb);
 120 }
 121
 122 /*
 123  * Figure out, may we reply to this packet with icmp error.
 124  *
 125  * We do not reply, if:
 126  *      - it was icmp error message.
 127  *      - it is truncated, so that it is known, that protocol is ICMPV6
 128  *        (i.e. in the middle of some exthdr)
 129  *
 130  *      --ANK (980726)
 131  */
 132
 133 static int is_ineligible(struct sk_buff *skb)
 134 {
 135         int ptr = (u8 *)(ipv6_hdr(skb) + 1) - skb->data;
 136         int len = skb->len - ptr;
 137         __u8 nexthdr = ipv6_hdr(skb)->nexthdr;
 138         __be16 frag_off;
 139
 140         if (len < 0)
 141                 return 1;
 142
 143         ptr = ipv6_skip_exthdr(skb, ptr, &nexthdr, &frag_off);
 144         if (ptr < 0)
 145                 return 0;
 146         if (nexthdr == IPPROTO_ICMPV6) {
 147                 u8 _type, *tp;
 148                 tp = skb_header_pointer(skb,
 149                         ptr+offsetof(struct icmp6hdr, icmp6_type),
 150                         sizeof(_type), &_type);
 151                 if (tp == NULL ||
 152                     !(*tp & ICMPV6_INFOMSG_MASK))
 153                         return 1;
 154         }
 155         return 0;
 156 }
 157
 158 /*
 159  * Check the ICMP output rate limit
 160  */
 161 static inline bool icmpv6_xrlim_allow(struct sock *sk, u8 type,
 162                                       struct flowi6 *fl6)
 163 {
 164         struct dst_entry *dst;
 165         struct net *net = sock_net(sk);
 166         bool res = false;
 167
 168         /* Informational messages are not limited. */
 169         if (type & ICMPV6_INFOMSG_MASK)
 170                 return true;
 171
 172         /* Do not limit pmtu discovery, it would break it. */
 173         if (type == ICMPV6_PKT_TOOBIG)
 174                 return true;
 175
 176         /*
 177          * Look up the output route.
 178          * XXX: perhaps the expire for routing entries cloned by
 179          * this lookup should be more aggressive (not longer than timeout).
 180          */
 181         dst = ip6_route_output(net, sk, fl6);
 182         if (dst->error) {
 183                 IP6_INC_STATS(net, ip6_dst_idev(dst),
 184                               IPSTATS_MIB_OUTNOROUTES);
 185         } else if (dst->dev && (dst->dev->flags&IFF_LOOPBACK)) {
 186                 res = true;
 187         } else {
 188                 struct rt6_info *rt = (struct rt6_info *)dst;
 189                 int tmo = net->ipv6.sysctl.icmpv6_time;
 190
 191                 /* Give more bandwidth to wider prefixes. */
 192                 if (rt->rt6i_dst.plen < 128)
 193                         tmo >>= ((128 - rt->rt6i_dst.plen)>>5);
 194
 195                 if (!rt->rt6i_peer)
 196                         rt6_bind_peer(rt, 1);
 197                 res = inet_peer_xrlim_allow(rt->rt6i_peer, tmo);
 198         }
 199         dst_release(dst);
 200         return res;
 201 }
 202
 203 /*
 204  *      an inline helper for the "simple" if statement below
 205  *      checks if parameter problem report is caused by an
 206  *      unrecognized IPv6 option that has the Option Type
 207  *      highest-order two bits set to 10
 208  */
 209
 210 static __inline__ int opt_unrec(struct sk_buff *skb, __u32 offset)
 211 {
 212         u8 _optval, *op;
 213
 214         offset += skb_network_offset(skb);
 215         op = skb_header_pointer(skb, offset, sizeof(_optval), &_optval);
 216         if (op == NULL)
 217                 return 1;
 218         return (*op & 0xC0) == 0x80;
 219 }
 220
 221 static int icmpv6_push_pending_frames(struct sock *sk, struct flowi6 *fl6, struct icmp6hdr *thdr, int len)
 222 {
 223         struct sk_buff *skb;
 224         struct icmp6hdr *icmp6h;
 225         int err = 0;
 226
 227         if ((skb = skb_peek(&sk->sk_write_queue)) == NULL)
 228                 goto out;
 229
 230         icmp6h = icmp6_hdr(skb);
 231         memcpy(icmp6h, thdr, sizeof(struct icmp6hdr));
 232         icmp6h->icmp6_cksum = 0;
 233
 234         if (skb_queue_len(&sk->sk_write_queue) == 1) {
 235                 skb->csum = csum_partial(icmp6h,
 236                                         sizeof(struct icmp6hdr), skb->csum);
 237                 icmp6h->icmp6_cksum = csum_ipv6_magic(&fl6->saddr,
 238                                                       &fl6->daddr,
 239                                                       len, fl6->flowi6_proto,
 240                                                       skb->csum);
 241         } else {
 242                 __wsum tmp_csum = 0;
 243
 244                 skb_queue_walk(&sk->sk_write_queue, skb) {
 245                         tmp_csum = csum_add(tmp_csum, skb->csum);
 246                 }
 247
 248                 tmp_csum = csum_partial(icmp6h,
 249                                         sizeof(struct icmp6hdr), tmp_csum);
 250                 icmp6h->icmp6_cksum = csum_ipv6_magic(&fl6->saddr,
 251                                                       &fl6->daddr,
 252                                                       len, fl6->flowi6_proto,
 253                                                       tmp_csum);
 254         }
 255         ip6_push_pending_frames(sk);
 256 out:
 257         return err;
 258 }
 259
 260 struct icmpv6_msg {
 261         struct sk_buff  *skb;
 262         int             offset;
 263         uint8_t         type;
 264 };
 265
 266 static int icmpv6_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb)
 267 {
 268         struct icmpv6_msg *msg = (struct icmpv6_msg *) from;
 269         struct sk_buff *org_skb = msg->skb;
 270         __wsum csum = 0;
 271
 272         csum = skb_copy_and_csum_bits(org_skb, msg->offset + offset,
 273                                       to, len, csum);
 274         skb->csum = csum_block_add(skb->csum, csum, odd);
 275         if (!(msg->type & ICMPV6_INFOMSG_MASK))
 276                 nf_ct_attach(skb, org_skb);
 277         return 0;
 278 }
 279
 280 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
 281 static void mip6_addr_swap(struct sk_buff *skb)
 282 {
 283         struct ipv6hdr *iph = ipv6_hdr(skb);
 284         struct inet6_skb_parm *opt = IP6CB(skb);
 285         struct ipv6_destopt_hao *hao;
 286         struct in6_addr tmp;
 287         int off;
 288
 289         if (opt->dsthao) {
 290                 off = ipv6_find_tlv(skb, opt->dsthao, IPV6_TLV_HAO);
 291                 if (likely(off >= 0)) {
 292                         hao = (struct ipv6_destopt_hao *)
 293                                         (skb_network_header(skb) + off);
 294                         tmp = iph->saddr;
 295                         iph->saddr = hao->addr;
 296                         hao->addr = tmp;
 297                 }
 298         }
 299 }
 300 #else
 301 static inline void mip6_addr_swap(struct sk_buff *skb) {}
 302 #endif
 303
 304 static struct dst_entry *icmpv6_route_lookup(struct net *net, struct sk_buff *skb,
 305                                              struct sock *sk, struct flowi6 *fl6)
 306 {
 307         struct dst_entry *dst, *dst2;
 308         struct flowi6 fl2;
 309         int err;
 310
 311         err = ip6_dst_lookup(sk, &dst, fl6);
 312         if (err)
 313                 return ERR_PTR(err);
 314
 315         /*
 316          * We won't send icmp if the destination is known
 317          * anycast.
 318          */
 319         if (((struct rt6_info *)dst)->rt6i_flags & RTF_ANYCAST) {
 320                 LIMIT_NETDEBUG(KERN_DEBUG "icmpv6_send: acast source\n");
 321                 dst_release(dst);
 322                 return ERR_PTR(-EINVAL);
 323         }
 324
 325         /* No need to clone since we're just using its address. */
 326         dst2 = dst;
 327
 328         dst = xfrm_lookup(net, dst, flowi6_to_flowi(fl6), sk, 0);
 329         if (!IS_ERR(dst)) {
 330                 if (dst != dst2)
 331                         return dst;
 332         } else {
 333                 if (PTR_ERR(dst) == -EPERM)
 334                         dst = NULL;
 335                 else
 336                         return dst;
 337         }
 338
 339         err = xfrm_decode_session_reverse(skb, flowi6_to_flowi(&fl2), AF_INET6);
 340         if (err)
 341                 goto relookup_failed;
 342
 343         err = ip6_dst_lookup(sk, &dst2, &fl2);
 344         if (err)
 345                 goto relookup_failed;
 346
 347         dst2 = xfrm_lookup(net, dst2, flowi6_to_flowi(&fl2), sk, XFRM_LOOKUP_ICMP);
 348         if (!IS_ERR(dst2)) {
 349                 dst_release(dst);
 350                 dst = dst2;
 351         } else {
 352                 err = PTR_ERR(dst2);
 353                 if (err == -EPERM) {
 354                         dst_release(dst);
 355                         return dst2;
 356                 } else
 357                         goto relookup_failed;
 358         }
 359
 360 relookup_failed:
 361         if (dst)
 362                 return dst;
 363         return ERR_PTR(err);
 364 }
 365
 366 /*
 367  *      Send an ICMP message in response to a packet in error
 368  */
 369 void icmpv6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info)
 370 {
 371         struct net *net = dev_net(skb->dev);
 372         struct inet6_dev *idev = NULL;
 373         struct ipv6hdr *hdr = ipv6_hdr(skb);
 374         struct sock *sk;
 375         struct ipv6_pinfo *np;
 376         const struct in6_addr *saddr = NULL;
 377         struct dst_entry *dst;
 378         struct icmp6hdr tmp_hdr;
 379         struct flowi6 fl6;
 380         struct icmpv6_msg msg;
 381         int iif = 0;
 382         int addr_type = 0;
 383         int len;
 384         int hlimit;
 385         int err = 0;
 386
 387         if ((u8 *)hdr < skb->head ||
 388             (skb->network_header + sizeof(*hdr)) > skb->tail)
 389                 return;
 390
 391         /*
 392          *      Make sure we respect the rules
 393          *      i.e. RFC 1885 2.4(e)
 394          *      Rule (e.1) is enforced by not using icmpv6_send
 395          *      in any code that processes icmp errors.
 396          */
 397         addr_type = ipv6_addr_type(&hdr->daddr);
 398
 399         if (ipv6_chk_addr(net, &hdr->daddr, skb->dev, 0))
 400                 saddr = &hdr->daddr;
 401
 402         /*
 403          *      Dest addr check
 404          */
 405
 406         if ((addr_type & IPV6_ADDR_MULTICAST || skb->pkt_type != PACKET_HOST)) {
 407                 if (type != ICMPV6_PKT_TOOBIG &&
 408                     !(type == ICMPV6_PARAMPROB &&
 409                       code == ICMPV6_UNK_OPTION &&
 410                       (opt_unrec(skb, info))))
 411                         return;
 412
 413                 saddr = NULL;
 414         }
 415
 416         addr_type = ipv6_addr_type(&hdr->saddr);
 417
 418         /*
 419          *      Source addr check
 420          */
 421
 422         if (addr_type & IPV6_ADDR_LINKLOCAL)
 423                 iif = skb->dev->ifindex;
 424
 425         /*
 426          *      Must not send error if the source does not uniquely
 427          *      identify a single node (RFC2463 Section 2.4).
 428          *      We check unspecified / multicast addresses here,
 429          *      and anycast addresses will be checked later.
 430          */
 431         if ((addr_type == IPV6_ADDR_ANY) || (addr_type & IPV6_ADDR_MULTICAST)) {
 432                 LIMIT_NETDEBUG(KERN_DEBUG "icmpv6_send: addr_any/mcast source\n");
 433                 return;
 434         }
 435
 436         /*
 437          *      Never answer to a ICMP packet.
 438          */
 439         if (is_ineligible(skb)) {
 440                 LIMIT_NETDEBUG(KERN_DEBUG "icmpv6_send: no reply to icmp error\n");
 441                 return;
 442         }
 443
 444         mip6_addr_swap(skb);
 445
 446         memset(&fl6, 0, sizeof(fl6));
 447         fl6.flowi6_proto = IPPROTO_ICMPV6;
 448         fl6.daddr = hdr->saddr;
 449         if (saddr)
 450                 fl6.saddr = *saddr;
 451         fl6.flowi6_oif = iif;
 452         fl6.fl6_icmp_type = type;
 453         fl6.fl6_icmp_code = code;
 454         security_skb_classify_flow(skb, flowi6_to_flowi(&fl6));
 455
 456         sk = icmpv6_xmit_lock(net);
 457         if (sk == NULL)
 458                 return;
 459         np = inet6_sk(sk);
 460
 461         if (!icmpv6_xrlim_allow(sk, type, &fl6))
 462                 goto out;
 463
 464         tmp_hdr.icmp6_type = type;
 465         tmp_hdr.icmp6_code = code;
 466         tmp_hdr.icmp6_cksum = 0;
 467         tmp_hdr.icmp6_pointer = htonl(info);
 468
 469         if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr))
 470                 fl6.flowi6_oif = np->mcast_oif;
 471
 472         dst = icmpv6_route_lookup(net, skb, sk, &fl6);
 473         if (IS_ERR(dst))
 474                 goto out;
 475
 476         if (ipv6_addr_is_multicast(&fl6.daddr))
 477                 hlimit = np->mcast_hops;
 478         else
 479                 hlimit = np->hop_limit;
 480         if (hlimit < 0)
 481                 hlimit = ip6_dst_hoplimit(dst);
 482
 483         msg.skb = skb;
 484         msg.offset = skb_network_offset(skb);
 485         msg.type = type;
 486
 487         len = skb->len - msg.offset;
 488         len = min_t(unsigned int, len, IPV6_MIN_MTU - sizeof(struct ipv6hdr) -sizeof(struct icmp6hdr));
 489         if (len < 0) {
 490                 LIMIT_NETDEBUG(KERN_DEBUG "icmp: len problem\n");
 491                 goto out_dst_release;
 492         }
 493
 494         rcu_read_lock();
 495         idev = __in6_dev_get(skb->dev);
 496
 497         err = ip6_append_data(sk, icmpv6_getfrag, &msg,
 498                               len + sizeof(struct icmp6hdr),
 499                               sizeof(struct icmp6hdr), hlimit,
 500                               np->tclass, NULL, &fl6, (struct rt6_info*)dst,
 501                               MSG_DONTWAIT, np->dontfrag);
 502         if (err) {
 503                 ICMP6_INC_STATS_BH(net, idev, ICMP6_MIB_OUTERRORS);
 504                 ip6_flush_pending_frames(sk);
 505         } else {
 506                 err = icmpv6_push_pending_frames(sk, &fl6, &tmp_hdr,
 507                                                  len + sizeof(struct icmp6hdr));
 508         }
 509         rcu_read_unlock();
 510 out_dst_release:
 511         dst_release(dst);
 512 out:
 513         icmpv6_xmit_unlock(sk);
 514 }
 515 EXPORT_SYMBOL(icmpv6_send);
 516
 517 static void icmpv6_echo_reply(struct sk_buff *skb)
 518 {
 519         struct net *net = dev_net(skb->dev);
 520         struct sock *sk;
 521         struct inet6_dev *idev;
 522         struct ipv6_pinfo *np;
 523         const struct in6_addr *saddr = NULL;
 524         struct icmp6hdr *icmph = icmp6_hdr(skb);
 525         struct icmp6hdr tmp_hdr;
 526         struct flowi6 fl6;
 527         struct icmpv6_msg msg;
 528         struct dst_entry *dst;
 529         int err = 0;
 530         int hlimit;
 531
 532         saddr = &ipv6_hdr(skb)->daddr;
 533
 534         if (!ipv6_unicast_destination(skb))
 535                 saddr = NULL;
 536
 537         memcpy(&tmp_hdr, icmph, sizeof(tmp_hdr));
 538         tmp_hdr.icmp6_type = ICMPV6_ECHO_REPLY;
 539
 540         memset(&fl6, 0, sizeof(fl6));
 541         fl6.flowi6_proto = IPPROTO_ICMPV6;
 542         fl6.daddr = ipv6_hdr(skb)->saddr;
 543         if (saddr)
 544                 fl6.saddr = *saddr;
 545         fl6.flowi6_oif = skb->dev->ifindex;
 546         fl6.fl6_icmp_type = ICMPV6_ECHO_REPLY;
 547         security_skb_classify_flow(skb, flowi6_to_flowi(&fl6));
 548
 549         sk = icmpv6_xmit_lock(net);
 550         if (sk == NULL)
 551                 return;
 552         np = inet6_sk(sk);
 553
 554         if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr))
 555                 fl6.flowi6_oif = np->mcast_oif;
 556
 557         err = ip6_dst_lookup(sk, &dst, &fl6);
 558         if (err)
 559                 goto out;
 560         dst = xfrm_lookup(net, dst, flowi6_to_flowi(&fl6), sk, 0);
 561         if (IS_ERR(dst))
 562                 goto out;
 563
 564         if (ipv6_addr_is_multicast(&fl6.daddr))
 565                 hlimit = np->mcast_hops;
 566         else
 567                 hlimit = np->hop_limit;
 568         if (hlimit < 0)
 569                 hlimit = ip6_dst_hoplimit(dst);
 570
 571         idev = __in6_dev_get(skb->dev);
 572
 573         msg.skb = skb;
 574         msg.offset = 0;
 575         msg.type = ICMPV6_ECHO_REPLY;
 576
 577         err = ip6_append_data(sk, icmpv6_getfrag, &msg, skb->len + sizeof(struct icmp6hdr),
 578                                 sizeof(struct icmp6hdr), hlimit, np->tclass, NULL, &fl6,
 579                                 (struct rt6_info*)dst, MSG_DONTWAIT,
 580                                 np->dontfrag);
 581
 582         if (err) {
 583                 ICMP6_INC_STATS_BH(net, idev, ICMP6_MIB_OUTERRORS);
 584                 ip6_flush_pending_frames(sk);
 585         } else {
 586                 err = icmpv6_push_pending_frames(sk, &fl6, &tmp_hdr,
 587                                                  skb->len + sizeof(struct icmp6hdr));
 588         }
 589         dst_release(dst);
 590 out:
 591         icmpv6_xmit_unlock(sk);
 592 }
 593
 594 static void icmpv6_notify(struct sk_buff *skb, u8 type, u8 code, __be32 info)
 595 {
 596         const struct inet6_protocol *ipprot;
 597         int inner_offset;
 598         int hash;
 599         u8 nexthdr;
 600         __be16 frag_off;
 601
 602         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
 603                 return;
 604
 605         nexthdr = ((struct ipv6hdr *)skb->data)->nexthdr;
 606         if (ipv6_ext_hdr(nexthdr)) {
 607                 /* now skip over extension headers */
 608                 inner_offset = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr),
 609                                                 &nexthdr, &frag_off);
 610                 if (inner_offset<0)
 611                         return;
 612         } else {
 613                 inner_offset = sizeof(struct ipv6hdr);
 614         }
 615
 616         /* Checkin header including 8 bytes of inner protocol header. */
 617         if (!pskb_may_pull(skb, inner_offset+8))
 618                 return;
 619
 620         /* BUGGG_FUTURE: we should try to parse exthdrs in this packet.
 621            Without this we will not able f.e. to make source routed
 622            pmtu discovery.
 623            Corresponding argument (opt) to notifiers is already added.
 624            --ANK (980726)
 625          */
 626
 627         hash = nexthdr & (MAX_INET_PROTOS - 1);
 628
 629         rcu_read_lock();
 630         ipprot = rcu_dereference(inet6_protos[hash]);
 631         if (ipprot && ipprot->err_handler)
 632                 ipprot->err_handler(skb, NULL, type, code, inner_offset, info);
 633         rcu_read_unlock();
 634
 635         raw6_icmp_error(skb, nexthdr, type, code, inner_offset, info);
 636 }
 637
 638 /*
 639  *      Handle icmp messages
 640  */
 641
 642 static int icmpv6_rcv(struct sk_buff *skb)
 643 {
 644         struct net_device *dev = skb->dev;
 645         struct inet6_dev *idev = __in6_dev_get(dev);
 646         const struct in6_addr *saddr, *daddr;
 647         const struct ipv6hdr *orig_hdr;
 648         struct icmp6hdr *hdr;
 649         u8 type;
 650
 651         if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
 652                 struct sec_path *sp = skb_sec_path(skb);
 653                 int nh;
 654
 655                 if (!(sp && sp->xvec[sp->len - 1]->props.flags &
 656                                  XFRM_STATE_ICMP))
 657                         goto drop_no_count;
 658
 659                 if (!pskb_may_pull(skb, sizeof(*hdr) + sizeof(*orig_hdr)))
 660                         goto drop_no_count;
 661
 662                 nh = skb_network_offset(skb);
 663                 skb_set_network_header(skb, sizeof(*hdr));
 664
 665                 if (!xfrm6_policy_check_reverse(NULL, XFRM_POLICY_IN, skb))
 666                         goto drop_no_count;
 667
 668                 skb_set_network_header(skb, nh);
 669         }
 670
 671         ICMP6_INC_STATS_BH(dev_net(dev), idev, ICMP6_MIB_INMSGS);
 672
 673         saddr = &ipv6_hdr(skb)->saddr;
 674         daddr = &ipv6_hdr(skb)->daddr;
 675
 676         /* Perform checksum. */
 677         switch (skb->ip_summed) {
 678         case CHECKSUM_COMPLETE:
 679                 if (!csum_ipv6_magic(saddr, daddr, skb->len, IPPROTO_ICMPV6,
 680                                      skb->csum))
 681                         break;
 682                 /* fall through */
 683         case CHECKSUM_NONE:
 684                 skb->csum = ~csum_unfold(csum_ipv6_magic(saddr, daddr, skb->len,
 685                                              IPPROTO_ICMPV6, 0));
 686                 if (__skb_checksum_complete(skb)) {
 687                         LIMIT_NETDEBUG(KERN_DEBUG "ICMPv6 checksum failed [%pI6 > %pI6]\n",
 688                                        saddr, daddr);
 689                         goto discard_it;
 690                 }
 691         }
 692
 693         if (!pskb_pull(skb, sizeof(*hdr)))
 694                 goto discard_it;
 695
 696         hdr = icmp6_hdr(skb);
 697
 698         type = hdr->icmp6_type;
 699
 700         ICMP6MSGIN_INC_STATS_BH(dev_net(dev), idev, type);
 701
 702         switch (type) {
 703         case ICMPV6_ECHO_REQUEST:
 704                 icmpv6_echo_reply(skb);
 705                 break;
 706
 707         case ICMPV6_ECHO_REPLY:
 708                 /* we couldn't care less */
 709                 break;
 710
 711         case ICMPV6_PKT_TOOBIG:
 712                 /* BUGGG_FUTURE: if packet contains rthdr, we cannot update
 713                    standard destination cache. Seems, only "advanced"
 714                    destination cache will allow to solve this problem
 715                    --ANK (980726)
 716                  */
 717                 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
 718                         goto discard_it;
 719                 hdr = icmp6_hdr(skb);
 720                 orig_hdr = (struct ipv6hdr *) (hdr + 1);
 721                 rt6_pmtu_discovery(&orig_hdr->daddr, &orig_hdr->saddr, dev,
 722                                    ntohl(hdr->icmp6_mtu));
 723
 724                 /*
 725                  *      Drop through to notify
 726                  */
 727
 728         case ICMPV6_DEST_UNREACH:
 729         case ICMPV6_TIME_EXCEED:
 730         case ICMPV6_PARAMPROB:
 731                 icmpv6_notify(skb, type, hdr->icmp6_code, hdr->icmp6_mtu);
 732                 break;
 733
 734         case NDISC_ROUTER_SOLICITATION:
 735         case NDISC_ROUTER_ADVERTISEMENT:
 736         case NDISC_NEIGHBOUR_SOLICITATION:
 737         case NDISC_NEIGHBOUR_ADVERTISEMENT:
 738         case NDISC_REDIRECT:
 739                 ndisc_rcv(skb);
 740                 break;
 741
 742         case ICMPV6_MGM_QUERY:
 743                 igmp6_event_query(skb);
 744                 break;
 745
 746         case ICMPV6_MGM_REPORT:
 747                 igmp6_event_report(skb);
 748                 break;
 749
 750         case ICMPV6_MGM_REDUCTION:
 751         case ICMPV6_NI_QUERY:
 752         case ICMPV6_NI_REPLY:
 753         case ICMPV6_MLD2_REPORT:
 754         case ICMPV6_DHAAD_REQUEST:
 755         case ICMPV6_DHAAD_REPLY:
 756         case ICMPV6_MOBILE_PREFIX_SOL:
 757         case ICMPV6_MOBILE_PREFIX_ADV:
 758                 break;
 759
 760         default:
 761                 LIMIT_NETDEBUG(KERN_DEBUG "icmpv6: msg of unknown type\n");
 762
 763                 /* informational */
 764                 if (type & ICMPV6_INFOMSG_MASK)
 765                         break;
 766
 767                 /*
 768                  * error of unknown type.
 769                  * must pass to upper level
 770                  */
 771
 772                 icmpv6_notify(skb, type, hdr->icmp6_code, hdr->icmp6_mtu);
 773         }
 774
 775         kfree_skb(skb);
 776         return 0;
 777
 778 discard_it:
 779         ICMP6_INC_STATS_BH(dev_net(dev), idev, ICMP6_MIB_INERRORS);
 780 drop_no_count:
 781         kfree_skb(skb);
 782         return 0;
 783 }
 784
 785 void icmpv6_flow_init(struct sock *sk, struct flowi6 *fl6,
 786                       u8 type,
 787                       const struct in6_addr *saddr,
 788                       const struct in6_addr *daddr,
 789                       int oif)
 790 {
 791         memset(fl6, 0, sizeof(*fl6));
 792         fl6->saddr = *saddr;
 793         fl6->daddr = *daddr;
 794         fl6->flowi6_proto       = IPPROTO_ICMPV6;
 795         fl6->fl6_icmp_type      = type;
 796         fl6->fl6_icmp_code      = 0;
 797         fl6->flowi6_oif         = oif;
 798         security_sk_classify_flow(sk, flowi6_to_flowi(fl6));
 799 }
 800
 801 /*
 802  * Special lock-class for __icmpv6_sk:
 803  */
 804 static struct lock_class_key icmpv6_socket_sk_dst_lock_key;
 805
 806 static int __net_init icmpv6_sk_init(struct net *net)
 807 {
 808         struct sock *sk;
 809         int err, i, j;
 810
 811         net->ipv6.icmp_sk =
 812                 kzalloc(nr_cpu_ids * sizeof(struct sock *), GFP_KERNEL);
 813         if (net->ipv6.icmp_sk == NULL)
 814                 return -ENOMEM;
 815
 816         for_each_possible_cpu(i) {
 817                 err = inet_ctl_sock_create(&sk, PF_INET6,
 818                                            SOCK_RAW, IPPROTO_ICMPV6, net);
 819                 if (err < 0) {
 820                         printk(KERN_ERR
 821                                "Failed to initialize the ICMP6 control socket "
 822                                "(err %d).\n",
 823                                err);
 824                         goto fail;
 825                 }
 826
 827                 net->ipv6.icmp_sk[i] = sk;
 828
 829                 /*
 830                  * Split off their lock-class, because sk->sk_dst_lock
 831                  * gets used from softirqs, which is safe for
 832                  * __icmpv6_sk (because those never get directly used
 833                  * via userspace syscalls), but unsafe for normal sockets.
 834                  */
 835                 lockdep_set_class(&sk->sk_dst_lock,
 836                                   &icmpv6_socket_sk_dst_lock_key);
 837
 838                 /* Enough space for 2 64K ICMP packets, including
 839                  * sk_buff struct overhead.
 840                  */
 841                 sk->sk_sndbuf = 2 * SKB_TRUESIZE(64 * 1024);
 842         }
 843         return 0;
 844
 845  fail:
 846         for (j = 0; j < i; j++)
 847                 inet_ctl_sock_destroy(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                 inet_ctl_sock_destroy(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(u8 type, u8 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                 .procname       = "ratelimit",
 957                 .data           = &init_net.ipv6.sysctl.icmpv6_time,
 958                 .maxlen         = sizeof(int),
 959                 .mode           = 0644,
 960                 .proc_handler   = proc_dointvec_ms_jiffies,
 961         },
 962         { },
 963 };
 964
 965 struct ctl_table * __net_init ipv6_icmp_sysctl_init(struct net *net)
 966 {
 967         struct ctl_table *table;
 968
 969         table = kmemdup(ipv6_icmp_table_template,
 970                         sizeof(ipv6_icmp_table_template),
 971                         GFP_KERNEL);
 972
 973         if (table)
 974                 table[0].data = &net->ipv6.sysctl.icmpv6_time;
 975
 976         return table;
 977 }
 978 #endif
 979