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 #define pr_fmt(fmt) "IPv6: " fmt
  33
  34 #include <linux/module.h>
  35 #include <linux/errno.h>
  36 #include <linux/types.h>
  37 #include <linux/socket.h>
  38 #include <linux/in.h>
  39 #include <linux/kernel.h>
  40 #include <linux/sockios.h>
  41 #include <linux/net.h>
  42 #include <linux/skbuff.h>
  43 #include <linux/init.h>
  44 #include <linux/netfilter.h>
  45 #include <linux/slab.h>
  46
  47 #ifdef CONFIG_SYSCTL
  48 #include <linux/sysctl.h>
  49 #endif
  50
  51 #include <linux/inet.h>
  52 #include <linux/netdevice.h>
  53 #include <linux/icmpv6.h>
  54
  55 #include <net/ip.h>
  56 #include <net/sock.h>
  57
  58 #include <net/ipv6.h>
  59 #include <net/ip6_checksum.h>
  60 #include <net/ping.h>
  61 #include <net/protocol.h>
  62 #include <net/raw.h>
  63 #include <net/rawv6.h>
  64 #include <net/transp_v6.h>
  65 #include <net/ip6_route.h>
  66 #include <net/addrconf.h>
  67 #include <net/icmp.h>
  68 #include <net/xfrm.h>
  69 #include <net/inet_common.h>
  70 #include <net/dsfield.h>
  71 #include <net/l3mdev.h>
  72
  73 #include <asm/uaccess.h>
  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 void icmpv6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
  88                        u8 type, u8 code, int offset, __be32 info)
  89 {
  90         /* icmpv6_notify checks 8 bytes can be pulled, icmp6hdr is 8 bytes */
  91         struct icmp6hdr *icmp6 = (struct icmp6hdr *) (skb->data + offset);
  92         struct net *net = dev_net(skb->dev);
  93
  94         if (type == ICMPV6_PKT_TOOBIG)
  95                 ip6_update_pmtu(skb, net, info, 0, 0);
  96         else if (type == NDISC_REDIRECT)
  97                 ip6_redirect(skb, net, skb->dev->ifindex, 0);
  98
  99         if (!(type & ICMPV6_INFOMSG_MASK))
 100                 if (icmp6->icmp6_type == ICMPV6_ECHO_REQUEST)
 101                         ping_err(skb, offset, ntohl(info));
 102 }
 103
 104 static int icmpv6_rcv(struct sk_buff *skb);
 105
 106 static const struct inet6_protocol icmpv6_protocol = {
 107         .handler        =       icmpv6_rcv,
 108         .err_handler    =       icmpv6_err,
 109         .flags          =       INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
 110 };
 111
 112 static __inline__ struct sock *icmpv6_xmit_lock(struct net *net)
 113 {
 114         struct sock *sk;
 115
 116         local_bh_disable();
 117
 118         sk = icmpv6_sk(net);
 119         if (unlikely(!spin_trylock(&sk->sk_lock.slock))) {
 120                 /* This can happen if the output path (f.e. SIT or
 121                  * ip6ip6 tunnel) signals dst_link_failure() for an
 122                  * outgoing ICMP6 packet.
 123                  */
 124                 local_bh_enable();
 125                 return NULL;
 126         }
 127         return sk;
 128 }
 129
 130 static __inline__ void icmpv6_xmit_unlock(struct sock *sk)
 131 {
 132         spin_unlock_bh(&sk->sk_lock.slock);
 133 }
 134
 135 /*
 136  * Figure out, may we reply to this packet with icmp error.
 137  *
 138  * We do not reply, if:
 139  *      - it was icmp error message.
 140  *      - it is truncated, so that it is known, that protocol is ICMPV6
 141  *        (i.e. in the middle of some exthdr)
 142  *
 143  *      --ANK (980726)
 144  */
 145
 146 static bool is_ineligible(const struct sk_buff *skb)
 147 {
 148         int ptr = (u8 *)(ipv6_hdr(skb) + 1) - skb->data;
 149         int len = skb->len - ptr;
 150         __u8 nexthdr = ipv6_hdr(skb)->nexthdr;
 151         __be16 frag_off;
 152
 153         if (len < 0)
 154                 return true;
 155
 156         ptr = ipv6_skip_exthdr(skb, ptr, &nexthdr, &frag_off);
 157         if (ptr < 0)
 158                 return false;
 159         if (nexthdr == IPPROTO_ICMPV6) {
 160                 u8 _type, *tp;
 161                 tp = skb_header_pointer(skb,
 162                         ptr+offsetof(struct icmp6hdr, icmp6_type),
 163                         sizeof(_type), &_type);
 164                 if (!tp || !(*tp & ICMPV6_INFOMSG_MASK))
 165                         return true;
 166         }
 167         return false;
 168 }
 169
 170 /*
 171  * Check the ICMP output rate limit
 172  */
 173 static bool icmpv6_xrlim_allow(struct sock *sk, u8 type,
 174                                struct flowi6 *fl6)
 175 {
 176         struct net *net = sock_net(sk);
 177         struct dst_entry *dst;
 178         bool res = false;
 179
 180         /* Informational messages are not limited. */
 181         if (type & ICMPV6_INFOMSG_MASK)
 182                 return true;
 183
 184         /* Do not limit pmtu discovery, it would break it. */
 185         if (type == ICMPV6_PKT_TOOBIG)
 186                 return true;
 187
 188         /*
 189          * Look up the output route.
 190          * XXX: perhaps the expire for routing entries cloned by
 191          * this lookup should be more aggressive (not longer than timeout).
 192          */
 193         dst = ip6_route_output(net, sk, fl6);
 194         if (dst->error) {
 195                 IP6_INC_STATS(net, ip6_dst_idev(dst),
 196                               IPSTATS_MIB_OUTNOROUTES);
 197         } else if (dst->dev && (dst->dev->flags&IFF_LOOPBACK)) {
 198                 res = true;
 199         } else {
 200                 struct rt6_info *rt = (struct rt6_info *)dst;
 201                 int tmo = net->ipv6.sysctl.icmpv6_time;
 202
 203                 /* Give more bandwidth to wider prefixes. */
 204                 if (rt->rt6i_dst.plen < 128)
 205                         tmo >>= ((128 - rt->rt6i_dst.plen)>>5);
 206
 207                 if (icmp_global_allow()) {
 208                         struct inet_peer *peer;
 209
 210                         peer = inet_getpeer_v6(net->ipv6.peers,
 211                                                &fl6->daddr, 1);
 212                         res = inet_peer_xrlim_allow(peer, tmo);
 213                         if (peer)
 214                                 inet_putpeer(peer);
 215                 }
 216         }
 217         dst_release(dst);
 218         return res;
 219 }
 220
 221 /*
 222  *      an inline helper for the "simple" if statement below
 223  *      checks if parameter problem report is caused by an
 224  *      unrecognized IPv6 option that has the Option Type
 225  *      highest-order two bits set to 10
 226  */
 227
 228 static bool opt_unrec(struct sk_buff *skb, __u32 offset)
 229 {
 230         u8 _optval, *op;
 231
 232         offset += skb_network_offset(skb);
 233         op = skb_header_pointer(skb, offset, sizeof(_optval), &_optval);
 234         if (!op)
 235                 return true;
 236         return (*op & 0xC0) == 0x80;
 237 }
 238
 239 int icmpv6_push_pending_frames(struct sock *sk, struct flowi6 *fl6,
 240                                struct icmp6hdr *thdr, int len)
 241 {
 242         struct sk_buff *skb;
 243         struct icmp6hdr *icmp6h;
 244         int err = 0;
 245
 246         skb = skb_peek(&sk->sk_write_queue);
 247         if (!skb)
 248                 goto out;
 249
 250         icmp6h = icmp6_hdr(skb);
 251         memcpy(icmp6h, thdr, sizeof(struct icmp6hdr));
 252         icmp6h->icmp6_cksum = 0;
 253
 254         if (skb_queue_len(&sk->sk_write_queue) == 1) {
 255                 skb->csum = csum_partial(icmp6h,
 256                                         sizeof(struct icmp6hdr), skb->csum);
 257                 icmp6h->icmp6_cksum = csum_ipv6_magic(&fl6->saddr,
 258                                                       &fl6->daddr,
 259                                                       len, fl6->flowi6_proto,
 260                                                       skb->csum);
 261         } else {
 262                 __wsum tmp_csum = 0;
 263
 264                 skb_queue_walk(&sk->sk_write_queue, skb) {
 265                         tmp_csum = csum_add(tmp_csum, skb->csum);
 266                 }
 267
 268                 tmp_csum = csum_partial(icmp6h,
 269                                         sizeof(struct icmp6hdr), tmp_csum);
 270                 icmp6h->icmp6_cksum = csum_ipv6_magic(&fl6->saddr,
 271                                                       &fl6->daddr,
 272                                                       len, fl6->flowi6_proto,
 273                                                       tmp_csum);
 274         }
 275         ip6_push_pending_frames(sk);
 276 out:
 277         return err;
 278 }
 279
 280 struct icmpv6_msg {
 281         struct sk_buff  *skb;
 282         int             offset;
 283         uint8_t         type;
 284 };
 285
 286 static int icmpv6_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb)
 287 {
 288         struct icmpv6_msg *msg = (struct icmpv6_msg *) from;
 289         struct sk_buff *org_skb = msg->skb;
 290         __wsum csum = 0;
 291
 292         csum = skb_copy_and_csum_bits(org_skb, msg->offset + offset,
 293                                       to, len, csum);
 294         skb->csum = csum_block_add(skb->csum, csum, odd);
 295         if (!(msg->type & ICMPV6_INFOMSG_MASK))
 296                 nf_ct_attach(skb, org_skb);
 297         return 0;
 298 }
 299
 300 #if IS_ENABLED(CONFIG_IPV6_MIP6)
 301 static void mip6_addr_swap(struct sk_buff *skb)
 302 {
 303         struct ipv6hdr *iph = ipv6_hdr(skb);
 304         struct inet6_skb_parm *opt = IP6CB(skb);
 305         struct ipv6_destopt_hao *hao;
 306         struct in6_addr tmp;
 307         int off;
 308
 309         if (opt->dsthao) {
 310                 off = ipv6_find_tlv(skb, opt->dsthao, IPV6_TLV_HAO);
 311                 if (likely(off >= 0)) {
 312                         hao = (struct ipv6_destopt_hao *)
 313                                         (skb_network_header(skb) + off);
 314                         tmp = iph->saddr;
 315                         iph->saddr = hao->addr;
 316                         hao->addr = tmp;
 317                 }
 318         }
 319 }
 320 #else
 321 static inline void mip6_addr_swap(struct sk_buff *skb) {}
 322 #endif
 323
 324 static struct dst_entry *icmpv6_route_lookup(struct net *net,
 325                                              struct sk_buff *skb,
 326                                              struct sock *sk,
 327                                              struct flowi6 *fl6)
 328 {
 329         struct dst_entry *dst, *dst2;
 330         struct flowi6 fl2;
 331         int err;
 332
 333         err = ip6_dst_lookup(net, sk, &dst, fl6);
 334         if (err)
 335                 return ERR_PTR(err);
 336
 337         /*
 338          * We won't send icmp if the destination is known
 339          * anycast.
 340          */
 341         if (ipv6_anycast_destination(dst, &fl6->daddr)) {
 342                 net_dbg_ratelimited("icmp6_send: acast source\n");
 343                 dst_release(dst);
 344                 return ERR_PTR(-EINVAL);
 345         }
 346
 347         /* No need to clone since we're just using its address. */
 348         dst2 = dst;
 349
 350         dst = xfrm_lookup(net, dst, flowi6_to_flowi(fl6), sk, 0);
 351         if (!IS_ERR(dst)) {
 352                 if (dst != dst2)
 353                         return dst;
 354         } else {
 355                 if (PTR_ERR(dst) == -EPERM)
 356                         dst = NULL;
 357                 else
 358                         return dst;
 359         }
 360
 361         err = xfrm_decode_session_reverse(skb, flowi6_to_flowi(&fl2), AF_INET6);
 362         if (err)
 363                 goto relookup_failed;
 364
 365         err = ip6_dst_lookup(net, sk, &dst2, &fl2);
 366         if (err)
 367                 goto relookup_failed;
 368
 369         dst2 = xfrm_lookup(net, dst2, flowi6_to_flowi(&fl2), sk, XFRM_LOOKUP_ICMP);
 370         if (!IS_ERR(dst2)) {
 371                 dst_release(dst);
 372                 dst = dst2;
 373         } else {
 374                 err = PTR_ERR(dst2);
 375                 if (err == -EPERM) {
 376                         dst_release(dst);
 377                         return dst2;
 378                 } else
 379                         goto relookup_failed;
 380         }
 381
 382 relookup_failed:
 383         if (dst)
 384                 return dst;
 385         return ERR_PTR(err);
 386 }
 387
 388 /*
 389  *      Send an ICMP message in response to a packet in error
 390  */
 391 static void icmp6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info,
 392                        const struct in6_addr *force_saddr)
 393 {
 394         struct net *net = dev_net(skb->dev);
 395         struct inet6_dev *idev = NULL;
 396         struct ipv6hdr *hdr = ipv6_hdr(skb);
 397         struct sock *sk;
 398         struct ipv6_pinfo *np;
 399         const struct in6_addr *saddr = NULL;
 400         struct dst_entry *dst;
 401         struct icmp6hdr tmp_hdr;
 402         struct flowi6 fl6;
 403         struct icmpv6_msg msg;
 404         struct sockcm_cookie sockc_unused = {0};
 405         struct ipcm6_cookie ipc6;
 406         int iif = 0;
 407         int addr_type = 0;
 408         int len;
 409         int err = 0;
 410         u32 mark = IP6_REPLY_MARK(net, skb->mark);
 411
 412         if ((u8 *)hdr < skb->head ||
 413             (skb_network_header(skb) + sizeof(*hdr)) > skb_tail_pointer(skb))
 414                 return;
 415
 416         /*
 417          *      Make sure we respect the rules
 418          *      i.e. RFC 1885 2.4(e)
 419          *      Rule (e.1) is enforced by not using icmp6_send
 420          *      in any code that processes icmp errors.
 421          */
 422         addr_type = ipv6_addr_type(&hdr->daddr);
 423
 424         if (ipv6_chk_addr(net, &hdr->daddr, skb->dev, 0) ||
 425             ipv6_chk_acast_addr_src(net, skb->dev, &hdr->daddr))
 426                 saddr = &hdr->daddr;
 427
 428         /*
 429          *      Dest addr check
 430          */
 431
 432         if (addr_type & IPV6_ADDR_MULTICAST || skb->pkt_type != PACKET_HOST) {
 433                 if (type != ICMPV6_PKT_TOOBIG &&
 434                     !(type == ICMPV6_PARAMPROB &&
 435                       code == ICMPV6_UNK_OPTION &&
 436                       (opt_unrec(skb, info))))
 437                         return;
 438
 439                 saddr = NULL;
 440         }
 441
 442         addr_type = ipv6_addr_type(&hdr->saddr);
 443
 444         /*
 445          *      Source addr check
 446          */
 447
 448         if (__ipv6_addr_needs_scope_id(addr_type))
 449                 iif = skb->dev->ifindex;
 450         else
 451                 iif = l3mdev_master_ifindex(skb->dev);
 452
 453         /*
 454          *      Must not send error if the source does not uniquely
 455          *      identify a single node (RFC2463 Section 2.4).
 456          *      We check unspecified / multicast addresses here,
 457          *      and anycast addresses will be checked later.
 458          */
 459         if ((addr_type == IPV6_ADDR_ANY) || (addr_type & IPV6_ADDR_MULTICAST)) {
 460                 net_dbg_ratelimited("icmp6_send: addr_any/mcast source [%pI6c > %pI6c]\n",
 461                                     &hdr->saddr, &hdr->daddr);
 462                 return;
 463         }
 464
 465         /*
 466          *      Never answer to a ICMP packet.
 467          */
 468         if (is_ineligible(skb)) {
 469                 net_dbg_ratelimited("icmp6_send: no reply to icmp error [%pI6c > %pI6c]\n",
 470                                     &hdr->saddr, &hdr->daddr);
 471                 return;
 472         }
 473
 474         mip6_addr_swap(skb);
 475
 476         memset(&fl6, 0, sizeof(fl6));
 477         fl6.flowi6_proto = IPPROTO_ICMPV6;
 478         fl6.daddr = hdr->saddr;
 479         if (force_saddr)
 480                 saddr = force_saddr;
 481         if (saddr)
 482                 fl6.saddr = *saddr;
 483         fl6.flowi6_mark = mark;
 484         fl6.flowi6_oif = iif;
 485         fl6.fl6_icmp_type = type;
 486         fl6.fl6_icmp_code = code;
 487         security_skb_classify_flow(skb, flowi6_to_flowi(&fl6));
 488
 489         sk = icmpv6_xmit_lock(net);
 490         if (!sk)
 491                 return;
 492         sk->sk_mark = mark;
 493         np = inet6_sk(sk);
 494
 495         if (!icmpv6_xrlim_allow(sk, type, &fl6))
 496                 goto out;
 497
 498         tmp_hdr.icmp6_type = type;
 499         tmp_hdr.icmp6_code = code;
 500         tmp_hdr.icmp6_cksum = 0;
 501         tmp_hdr.icmp6_pointer = htonl(info);
 502
 503         if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr))
 504                 fl6.flowi6_oif = np->mcast_oif;
 505         else if (!fl6.flowi6_oif)
 506                 fl6.flowi6_oif = np->ucast_oif;
 507
 508         ipc6.tclass = np->tclass;
 509         fl6.flowlabel = ip6_make_flowinfo(ipc6.tclass, fl6.flowlabel);
 510
 511         dst = icmpv6_route_lookup(net, skb, sk, &fl6);
 512         if (IS_ERR(dst))
 513                 goto out;
 514
 515         ipc6.hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst);
 516         ipc6.dontfrag = np->dontfrag;
 517         ipc6.opt = NULL;
 518
 519         msg.skb = skb;
 520         msg.offset = skb_network_offset(skb);
 521         msg.type = type;
 522
 523         len = skb->len - msg.offset;
 524         len = min_t(unsigned int, len, IPV6_MIN_MTU - sizeof(struct ipv6hdr) - sizeof(struct icmp6hdr));
 525         if (len < 0) {
 526                 net_dbg_ratelimited("icmp: len problem [%pI6c > %pI6c]\n",
 527                                     &hdr->saddr, &hdr->daddr);
 528                 goto out_dst_release;
 529         }
 530
 531         rcu_read_lock();
 532         idev = __in6_dev_get(skb->dev);
 533
 534         err = ip6_append_data(sk, icmpv6_getfrag, &msg,
 535                               len + sizeof(struct icmp6hdr),
 536                               sizeof(struct icmp6hdr),
 537                               &ipc6, &fl6, (struct rt6_info *)dst,
 538                               MSG_DONTWAIT, &sockc_unused);
 539         if (err) {
 540                 ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTERRORS);
 541                 ip6_flush_pending_frames(sk);
 542         } else {
 543                 err = icmpv6_push_pending_frames(sk, &fl6, &tmp_hdr,
 544                                                  len + sizeof(struct icmp6hdr));
 545         }
 546         rcu_read_unlock();
 547 out_dst_release:
 548         dst_release(dst);
 549 out:
 550         icmpv6_xmit_unlock(sk);
 551 }
 552
 553 /* Slightly more convenient version of icmp6_send.
 554  */
 555 void icmpv6_param_prob(struct sk_buff *skb, u8 code, int pos)
 556 {
 557         icmp6_send(skb, ICMPV6_PARAMPROB, code, pos, NULL);
 558         kfree_skb(skb);
 559 }
 560
 561 /* Generate icmpv6 with type/code ICMPV6_DEST_UNREACH/ICMPV6_ADDR_UNREACH
 562  * if sufficient data bytes are available
 563  * @nhs is the size of the tunnel header(s) :
 564  *  Either an IPv4 header for SIT encap
 565  *         an IPv4 header + GRE header for GRE encap
 566  */
 567 int ip6_err_gen_icmpv6_unreach(struct sk_buff *skb, int nhs, int type,
 568                                unsigned int data_len)
 569 {
 570         struct in6_addr temp_saddr;
 571         struct rt6_info *rt;
 572         struct sk_buff *skb2;
 573         u32 info = 0;
 574
 575         if (!pskb_may_pull(skb, nhs + sizeof(struct ipv6hdr) + 8))
 576                 return 1;
 577
 578         /* RFC 4884 (partial) support for ICMP extensions */
 579         if (data_len < 128 || (data_len & 7) || skb->len < data_len)
 580                 data_len = 0;
 581
 582         skb2 = data_len ? skb_copy(skb, GFP_ATOMIC) : skb_clone(skb, GFP_ATOMIC);
 583
 584         if (!skb2)
 585                 return 1;
 586
 587         skb_dst_drop(skb2);
 588         skb_pull(skb2, nhs);
 589         skb_reset_network_header(skb2);
 590
 591         rt = rt6_lookup(dev_net(skb->dev), &ipv6_hdr(skb2)->saddr, NULL, 0, 0);
 592
 593         if (rt && rt->dst.dev)
 594                 skb2->dev = rt->dst.dev;
 595
 596         ipv6_addr_set_v4mapped(ip_hdr(skb)->saddr, &temp_saddr);
 597
 598         if (data_len) {
 599                 /* RFC 4884 (partial) support :
 600                  * insert 0 padding at the end, before the extensions
 601                  */
 602                 __skb_push(skb2, nhs);
 603                 skb_reset_network_header(skb2);
 604                 memmove(skb2->data, skb2->data + nhs, data_len - nhs);
 605                 memset(skb2->data + data_len - nhs, 0, nhs);
 606                 /* RFC 4884 4.5 : Length is measured in 64-bit words,
 607                  * and stored in reserved[0]
 608                  */
 609                 info = (data_len/8) << 24;
 610         }
 611         if (type == ICMP_TIME_EXCEEDED)
 612                 icmp6_send(skb2, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT,
 613                            info, &temp_saddr);
 614         else
 615                 icmp6_send(skb2, ICMPV6_DEST_UNREACH, ICMPV6_ADDR_UNREACH,
 616                            info, &temp_saddr);
 617         if (rt)
 618                 ip6_rt_put(rt);
 619
 620         kfree_skb(skb2);
 621
 622         return 0;
 623 }
 624 EXPORT_SYMBOL(ip6_err_gen_icmpv6_unreach);
 625
 626 static void icmpv6_echo_reply(struct sk_buff *skb)
 627 {
 628         struct net *net = dev_net(skb->dev);
 629         struct sock *sk;
 630         struct inet6_dev *idev;
 631         struct ipv6_pinfo *np;
 632         const struct in6_addr *saddr = NULL;
 633         struct icmp6hdr *icmph = icmp6_hdr(skb);
 634         struct icmp6hdr tmp_hdr;
 635         struct flowi6 fl6;
 636         struct icmpv6_msg msg;
 637         struct dst_entry *dst;
 638         struct ipcm6_cookie ipc6;
 639         int err = 0;
 640         u32 mark = IP6_REPLY_MARK(net, skb->mark);
 641         struct sockcm_cookie sockc_unused = {0};
 642
 643         saddr = &ipv6_hdr(skb)->daddr;
 644
 645         if (!ipv6_unicast_destination(skb) &&
 646             !(net->ipv6.sysctl.anycast_src_echo_reply &&
 647               ipv6_anycast_destination(skb_dst(skb), saddr)))
 648                 saddr = NULL;
 649
 650         memcpy(&tmp_hdr, icmph, sizeof(tmp_hdr));
 651         tmp_hdr.icmp6_type = ICMPV6_ECHO_REPLY;
 652
 653         memset(&fl6, 0, sizeof(fl6));
 654         fl6.flowi6_proto = IPPROTO_ICMPV6;
 655         fl6.daddr = ipv6_hdr(skb)->saddr;
 656         if (saddr)
 657                 fl6.saddr = *saddr;
 658         fl6.flowi6_oif = skb->dev->ifindex;
 659         fl6.fl6_icmp_type = ICMPV6_ECHO_REPLY;
 660         fl6.flowi6_mark = mark;
 661         security_skb_classify_flow(skb, flowi6_to_flowi(&fl6));
 662
 663         sk = icmpv6_xmit_lock(net);
 664         if (!sk)
 665                 return;
 666         sk->sk_mark = mark;
 667         np = inet6_sk(sk);
 668
 669         if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr))
 670                 fl6.flowi6_oif = np->mcast_oif;
 671         else if (!fl6.flowi6_oif)
 672                 fl6.flowi6_oif = np->ucast_oif;
 673
 674         err = ip6_dst_lookup(net, sk, &dst, &fl6);
 675         if (err)
 676                 goto out;
 677         dst = xfrm_lookup(net, dst, flowi6_to_flowi(&fl6), sk, 0);
 678         if (IS_ERR(dst))
 679                 goto out;
 680
 681         idev = __in6_dev_get(skb->dev);
 682
 683         msg.skb = skb;
 684         msg.offset = 0;
 685         msg.type = ICMPV6_ECHO_REPLY;
 686
 687         ipc6.hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst);
 688         ipc6.tclass = ipv6_get_dsfield(ipv6_hdr(skb));
 689         ipc6.dontfrag = np->dontfrag;
 690         ipc6.opt = NULL;
 691
 692         err = ip6_append_data(sk, icmpv6_getfrag, &msg, skb->len + sizeof(struct icmp6hdr),
 693                                 sizeof(struct icmp6hdr), &ipc6, &fl6,
 694                                 (struct rt6_info *)dst, MSG_DONTWAIT,
 695                                 &sockc_unused);
 696
 697         if (err) {
 698                 __ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTERRORS);
 699                 ip6_flush_pending_frames(sk);
 700         } else {
 701                 err = icmpv6_push_pending_frames(sk, &fl6, &tmp_hdr,
 702                                                  skb->len + sizeof(struct icmp6hdr));
 703         }
 704         dst_release(dst);
 705 out:
 706         icmpv6_xmit_unlock(sk);
 707 }
 708
 709 void icmpv6_notify(struct sk_buff *skb, u8 type, u8 code, __be32 info)
 710 {
 711         const struct inet6_protocol *ipprot;
 712         int inner_offset;
 713         __be16 frag_off;
 714         u8 nexthdr;
 715         struct net *net = dev_net(skb->dev);
 716
 717         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
 718                 goto out;
 719
 720         nexthdr = ((struct ipv6hdr *)skb->data)->nexthdr;
 721         if (ipv6_ext_hdr(nexthdr)) {
 722                 /* now skip over extension headers */
 723                 inner_offset = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr),
 724                                                 &nexthdr, &frag_off);
 725                 if (inner_offset < 0)
 726                         goto out;
 727         } else {
 728                 inner_offset = sizeof(struct ipv6hdr);
 729         }
 730
 731         /* Checkin header including 8 bytes of inner protocol header. */
 732         if (!pskb_may_pull(skb, inner_offset+8))
 733                 goto out;
 734
 735         /* BUGGG_FUTURE: we should try to parse exthdrs in this packet.
 736            Without this we will not able f.e. to make source routed
 737            pmtu discovery.
 738            Corresponding argument (opt) to notifiers is already added.
 739            --ANK (980726)
 740          */
 741
 742         ipprot = rcu_dereference(inet6_protos[nexthdr]);
 743         if (ipprot && ipprot->err_handler)
 744                 ipprot->err_handler(skb, NULL, type, code, inner_offset, info);
 745
 746         raw6_icmp_error(skb, nexthdr, type, code, inner_offset, info);
 747         return;
 748
 749 out:
 750         __ICMP6_INC_STATS(net, __in6_dev_get(skb->dev), ICMP6_MIB_INERRORS);
 751 }
 752
 753 /*
 754  *      Handle icmp messages
 755  */
 756
 757 static int icmpv6_rcv(struct sk_buff *skb)
 758 {
 759         struct net_device *dev = skb->dev;
 760         struct inet6_dev *idev = __in6_dev_get(dev);
 761         const struct in6_addr *saddr, *daddr;
 762         struct icmp6hdr *hdr;
 763         u8 type;
 764         bool success = false;
 765
 766         if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
 767                 struct sec_path *sp = skb_sec_path(skb);
 768                 int nh;
 769
 770                 if (!(sp && sp->xvec[sp->len - 1]->props.flags &
 771                                  XFRM_STATE_ICMP))
 772                         goto drop_no_count;
 773
 774                 if (!pskb_may_pull(skb, sizeof(*hdr) + sizeof(struct ipv6hdr)))
 775                         goto drop_no_count;
 776
 777                 nh = skb_network_offset(skb);
 778                 skb_set_network_header(skb, sizeof(*hdr));
 779
 780                 if (!xfrm6_policy_check_reverse(NULL, XFRM_POLICY_IN, skb))
 781                         goto drop_no_count;
 782
 783                 skb_set_network_header(skb, nh);
 784         }
 785
 786         __ICMP6_INC_STATS(dev_net(dev), idev, ICMP6_MIB_INMSGS);
 787
 788         saddr = &ipv6_hdr(skb)->saddr;
 789         daddr = &ipv6_hdr(skb)->daddr;
 790
 791         if (skb_checksum_validate(skb, IPPROTO_ICMPV6, ip6_compute_pseudo)) {
 792                 net_dbg_ratelimited("ICMPv6 checksum failed [%pI6c > %pI6c]\n",
 793                                     saddr, daddr);
 794                 goto csum_error;
 795         }
 796
 797         if (!pskb_pull(skb, sizeof(*hdr)))
 798                 goto discard_it;
 799
 800         hdr = icmp6_hdr(skb);
 801
 802         type = hdr->icmp6_type;
 803
 804         ICMP6MSGIN_INC_STATS(dev_net(dev), idev, type);
 805
 806         switch (type) {
 807         case ICMPV6_ECHO_REQUEST:
 808                 icmpv6_echo_reply(skb);
 809                 break;
 810
 811         case ICMPV6_ECHO_REPLY:
 812                 success = ping_rcv(skb);
 813                 break;
 814
 815         case ICMPV6_PKT_TOOBIG:
 816                 /* BUGGG_FUTURE: if packet contains rthdr, we cannot update
 817                    standard destination cache. Seems, only "advanced"
 818                    destination cache will allow to solve this problem
 819                    --ANK (980726)
 820                  */
 821                 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
 822                         goto discard_it;
 823                 hdr = icmp6_hdr(skb);
 824
 825                 /*
 826                  *      Drop through to notify
 827                  */
 828
 829         case ICMPV6_DEST_UNREACH:
 830         case ICMPV6_TIME_EXCEED:
 831         case ICMPV6_PARAMPROB:
 832                 icmpv6_notify(skb, type, hdr->icmp6_code, hdr->icmp6_mtu);
 833                 break;
 834
 835         case NDISC_ROUTER_SOLICITATION:
 836         case NDISC_ROUTER_ADVERTISEMENT:
 837         case NDISC_NEIGHBOUR_SOLICITATION:
 838         case NDISC_NEIGHBOUR_ADVERTISEMENT:
 839         case NDISC_REDIRECT:
 840                 ndisc_rcv(skb);
 841                 break;
 842
 843         case ICMPV6_MGM_QUERY:
 844                 igmp6_event_query(skb);
 845                 break;
 846
 847         case ICMPV6_MGM_REPORT:
 848                 igmp6_event_report(skb);
 849                 break;
 850
 851         case ICMPV6_MGM_REDUCTION:
 852         case ICMPV6_NI_QUERY:
 853         case ICMPV6_NI_REPLY:
 854         case ICMPV6_MLD2_REPORT:
 855         case ICMPV6_DHAAD_REQUEST:
 856         case ICMPV6_DHAAD_REPLY:
 857         case ICMPV6_MOBILE_PREFIX_SOL:
 858         case ICMPV6_MOBILE_PREFIX_ADV:
 859                 break;
 860
 861         default:
 862                 /* informational */
 863                 if (type & ICMPV6_INFOMSG_MASK)
 864                         break;
 865
 866                 net_dbg_ratelimited("icmpv6: msg of unknown type [%pI6c > %pI6c]\n",
 867                                     saddr, daddr);
 868
 869                 /*
 870                  * error of unknown type.
 871                  * must pass to upper level
 872                  */
 873
 874                 icmpv6_notify(skb, type, hdr->icmp6_code, hdr->icmp6_mtu);
 875         }
 876
 877         /* until the v6 path can be better sorted assume failure and
 878          * preserve the status quo behaviour for the rest of the paths to here
 879          */
 880         if (success)
 881                 consume_skb(skb);
 882         else
 883                 kfree_skb(skb);
 884
 885         return 0;
 886
 887 csum_error:
 888         __ICMP6_INC_STATS(dev_net(dev), idev, ICMP6_MIB_CSUMERRORS);
 889 discard_it:
 890         __ICMP6_INC_STATS(dev_net(dev), idev, ICMP6_MIB_INERRORS);
 891 drop_no_count:
 892         kfree_skb(skb);
 893         return 0;
 894 }
 895
 896 void icmpv6_flow_init(struct sock *sk, struct flowi6 *fl6,
 897                       u8 type,
 898                       const struct in6_addr *saddr,
 899                       const struct in6_addr *daddr,
 900                       int oif)
 901 {
 902         memset(fl6, 0, sizeof(*fl6));
 903         fl6->saddr = *saddr;
 904         fl6->daddr = *daddr;
 905         fl6->flowi6_proto       = IPPROTO_ICMPV6;
 906         fl6->fl6_icmp_type      = type;
 907         fl6->fl6_icmp_code      = 0;
 908         fl6->flowi6_oif         = oif;
 909         security_sk_classify_flow(sk, flowi6_to_flowi(fl6));
 910 }
 911
 912 static int __net_init icmpv6_sk_init(struct net *net)
 913 {
 914         struct sock *sk;
 915         int err, i, j;
 916
 917         net->ipv6.icmp_sk =
 918                 kzalloc(nr_cpu_ids * sizeof(struct sock *), GFP_KERNEL);
 919         if (!net->ipv6.icmp_sk)
 920                 return -ENOMEM;
 921
 922         for_each_possible_cpu(i) {
 923                 err = inet_ctl_sock_create(&sk, PF_INET6,
 924                                            SOCK_RAW, IPPROTO_ICMPV6, net);
 925                 if (err < 0) {
 926                         pr_err("Failed to initialize the ICMP6 control socket (err %d)\n",
 927                                err);
 928                         goto fail;
 929                 }
 930
 931                 net->ipv6.icmp_sk[i] = sk;
 932
 933                 /* Enough space for 2 64K ICMP packets, including
 934                  * sk_buff struct overhead.
 935                  */
 936                 sk->sk_sndbuf = 2 * SKB_TRUESIZE(64 * 1024);
 937         }
 938         return 0;
 939
 940  fail:
 941         for (j = 0; j < i; j++)
 942                 inet_ctl_sock_destroy(net->ipv6.icmp_sk[j]);
 943         kfree(net->ipv6.icmp_sk);
 944         return err;
 945 }
 946
 947 static void __net_exit icmpv6_sk_exit(struct net *net)
 948 {
 949         int i;
 950
 951         for_each_possible_cpu(i) {
 952                 inet_ctl_sock_destroy(net->ipv6.icmp_sk[i]);
 953         }
 954         kfree(net->ipv6.icmp_sk);
 955 }
 956
 957 static struct pernet_operations icmpv6_sk_ops = {
 958         .init = icmpv6_sk_init,
 959         .exit = icmpv6_sk_exit,
 960 };
 961
 962 int __init icmpv6_init(void)
 963 {
 964         int err;
 965
 966         err = register_pernet_subsys(&icmpv6_sk_ops);
 967         if (err < 0)
 968                 return err;
 969
 970         err = -EAGAIN;
 971         if (inet6_add_protocol(&icmpv6_protocol, IPPROTO_ICMPV6) < 0)
 972                 goto fail;
 973
 974         err = inet6_register_icmp_sender(icmp6_send);
 975         if (err)
 976                 goto sender_reg_err;
 977         return 0;
 978
 979 sender_reg_err:
 980         inet6_del_protocol(&icmpv6_protocol, IPPROTO_ICMPV6);
 981 fail:
 982         pr_err("Failed to register ICMP6 protocol\n");
 983         unregister_pernet_subsys(&icmpv6_sk_ops);
 984         return err;
 985 }
 986
 987 void icmpv6_cleanup(void)
 988 {
 989         inet6_unregister_icmp_sender(icmp6_send);
 990         unregister_pernet_subsys(&icmpv6_sk_ops);
 991         inet6_del_protocol(&icmpv6_protocol, IPPROTO_ICMPV6);
 992 }
 993
 994
 995 static const struct icmp6_err {
 996         int err;
 997         int fatal;
 998 } tab_unreach[] = {
 999         {       /* NOROUTE */
1000                 .err    = ENETUNREACH,
1001                 .fatal  = 0,
1002         },
1003         {       /* ADM_PROHIBITED */
1004                 .err    = EACCES,
1005                 .fatal  = 1,
1006         },
1007         {       /* Was NOT_NEIGHBOUR, now reserved */
1008                 .err    = EHOSTUNREACH,
1009                 .fatal  = 0,
1010         },
1011         {       /* ADDR_UNREACH */
1012                 .err    = EHOSTUNREACH,
1013                 .fatal  = 0,
1014         },
1015         {       /* PORT_UNREACH */
1016                 .err    = ECONNREFUSED,
1017                 .fatal  = 1,
1018         },
1019         {       /* POLICY_FAIL */
1020                 .err    = EACCES,
1021                 .fatal  = 1,
1022         },
1023         {       /* REJECT_ROUTE */
1024                 .err    = EACCES,
1025                 .fatal  = 1,
1026         },
1027 };
1028
1029 int icmpv6_err_convert(u8 type, u8 code, int *err)
1030 {
1031         int fatal = 0;
1032
1033         *err = EPROTO;
1034
1035         switch (type) {
1036         case ICMPV6_DEST_UNREACH:
1037                 fatal = 1;
1038                 if (code < ARRAY_SIZE(tab_unreach)) {
1039                         *err  = tab_unreach[code].err;
1040                         fatal = tab_unreach[code].fatal;
1041                 }
1042                 break;
1043
1044         case ICMPV6_PKT_TOOBIG:
1045                 *err = EMSGSIZE;
1046                 break;
1047
1048         case ICMPV6_PARAMPROB:
1049                 *err = EPROTO;
1050                 fatal = 1;
1051                 break;
1052
1053         case ICMPV6_TIME_EXCEED:
1054                 *err = EHOSTUNREACH;
1055                 break;
1056         }
1057
1058         return fatal;
1059 }
1060 EXPORT_SYMBOL(icmpv6_err_convert);
1061
1062 #ifdef CONFIG_SYSCTL
1063 static struct ctl_table ipv6_icmp_table_template[] = {
1064         {
1065                 .procname       = "ratelimit",
1066                 .data           = &init_net.ipv6.sysctl.icmpv6_time,
1067                 .maxlen         = sizeof(int),
1068                 .mode           = 0644,
1069                 .proc_handler   = proc_dointvec_ms_jiffies,
1070         },
1071         { },
1072 };
1073
1074 struct ctl_table * __net_init ipv6_icmp_sysctl_init(struct net *net)
1075 {
1076         struct ctl_table *table;
1077
1078         table = kmemdup(ipv6_icmp_table_template,
1079                         sizeof(ipv6_icmp_table_template),
1080                         GFP_KERNEL);
1081
1082         if (table)
1083                 table[0].data = &net->ipv6.sysctl.icmpv6_time;
1084
1085         return table;
1086 }
1087 #endif