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, 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 { 393 struct net *net = dev_net(skb->dev); 394 struct inet6_dev *idev = NULL; 395 struct ipv6hdr *hdr = ipv6_hdr(skb); 396 struct sock *sk; 397 struct ipv6_pinfo *np; 398 const struct in6_addr *saddr = NULL; 399 struct dst_entry *dst; 400 struct icmp6hdr tmp_hdr; 401 struct flowi6 fl6; 402 struct icmpv6_msg msg; 403 struct sockcm_cookie sockc_unused = {0}; 404 int iif = 0; 405 int addr_type = 0; 406 int len; 407 int hlimit; 408 int err = 0; 409 u32 mark = IP6_REPLY_MARK(net, skb->mark); 410 411 if ((u8 *)hdr < skb->head || 412 (skb_network_header(skb) + sizeof(*hdr)) > skb_tail_pointer(skb)) 413 return; 414 415 /* 416 * Make sure we respect the rules 417 * i.e. RFC 1885 2.4(e) 418 * Rule (e.1) is enforced by not using icmp6_send 419 * in any code that processes icmp errors. 420 */ 421 addr_type = ipv6_addr_type(&hdr->daddr); 422 423 if (ipv6_chk_addr(net, &hdr->daddr, skb->dev, 0) || 424 ipv6_chk_acast_addr_src(net, skb->dev, &hdr->daddr)) 425 saddr = &hdr->daddr; 426 427 /* 428 * Dest addr check 429 */ 430 431 if (addr_type & IPV6_ADDR_MULTICAST || skb->pkt_type != PACKET_HOST) { 432 if (type != ICMPV6_PKT_TOOBIG && 433 !(type == ICMPV6_PARAMPROB && 434 code == ICMPV6_UNK_OPTION && 435 (opt_unrec(skb, info)))) 436 return; 437 438 saddr = NULL; 439 } 440 441 addr_type = ipv6_addr_type(&hdr->saddr); 442 443 /* 444 * Source addr check 445 */ 446 447 if (__ipv6_addr_needs_scope_id(addr_type)) 448 iif = skb->dev->ifindex; 449 450 /* 451 * Must not send error if the source does not uniquely 452 * identify a single node (RFC2463 Section 2.4). 453 * We check unspecified / multicast addresses here, 454 * and anycast addresses will be checked later. 455 */ 456 if ((addr_type == IPV6_ADDR_ANY) || (addr_type & IPV6_ADDR_MULTICAST)) { 457 net_dbg_ratelimited("icmp6_send: addr_any/mcast source [%pI6c > %pI6c]\n", 458 &hdr->saddr, &hdr->daddr); 459 return; 460 } 461 462 /* 463 * Never answer to a ICMP packet. 464 */ 465 if (is_ineligible(skb)) { 466 net_dbg_ratelimited("icmp6_send: no reply to icmp error [%pI6c > %pI6c]\n", 467 &hdr->saddr, &hdr->daddr); 468 return; 469 } 470 471 mip6_addr_swap(skb); 472 473 memset(&fl6, 0, sizeof(fl6)); 474 fl6.flowi6_proto = IPPROTO_ICMPV6; 475 fl6.daddr = hdr->saddr; 476 if (saddr) 477 fl6.saddr = *saddr; 478 fl6.flowi6_mark = mark; 479 fl6.flowi6_oif = iif; 480 fl6.fl6_icmp_type = type; 481 fl6.fl6_icmp_code = code; 482 security_skb_classify_flow(skb, flowi6_to_flowi(&fl6)); 483 484 sk = icmpv6_xmit_lock(net); 485 if (!sk) 486 return; 487 sk->sk_mark = mark; 488 np = inet6_sk(sk); 489 490 if (!icmpv6_xrlim_allow(sk, type, &fl6)) 491 goto out; 492 493 tmp_hdr.icmp6_type = type; 494 tmp_hdr.icmp6_code = code; 495 tmp_hdr.icmp6_cksum = 0; 496 tmp_hdr.icmp6_pointer = htonl(info); 497 498 if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr)) 499 fl6.flowi6_oif = np->mcast_oif; 500 else if (!fl6.flowi6_oif) 501 fl6.flowi6_oif = np->ucast_oif; 502 503 if (!fl6.flowi6_oif) 504 fl6.flowi6_oif = l3mdev_master_ifindex(skb->dev); 505 506 dst = icmpv6_route_lookup(net, skb, sk, &fl6); 507 if (IS_ERR(dst)) 508 goto out; 509 510 hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst); 511 512 msg.skb = skb; 513 msg.offset = skb_network_offset(skb); 514 msg.type = type; 515 516 len = skb->len - msg.offset; 517 len = min_t(unsigned int, len, IPV6_MIN_MTU - sizeof(struct ipv6hdr) - sizeof(struct icmp6hdr)); 518 if (len < 0) { 519 net_dbg_ratelimited("icmp: len problem [%pI6c > %pI6c]\n", 520 &hdr->saddr, &hdr->daddr); 521 goto out_dst_release; 522 } 523 524 rcu_read_lock(); 525 idev = __in6_dev_get(skb->dev); 526 527 err = ip6_append_data(sk, icmpv6_getfrag, &msg, 528 len + sizeof(struct icmp6hdr), 529 sizeof(struct icmp6hdr), hlimit, 530 np->tclass, NULL, &fl6, (struct rt6_info *)dst, 531 MSG_DONTWAIT, np->dontfrag, &sockc_unused); 532 if (err) { 533 ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTERRORS); 534 ip6_flush_pending_frames(sk); 535 } else { 536 err = icmpv6_push_pending_frames(sk, &fl6, &tmp_hdr, 537 len + sizeof(struct icmp6hdr)); 538 } 539 rcu_read_unlock(); 540 out_dst_release: 541 dst_release(dst); 542 out: 543 icmpv6_xmit_unlock(sk); 544 } 545 546 /* Slightly more convenient version of icmp6_send. 547 */ 548 void icmpv6_param_prob(struct sk_buff *skb, u8 code, int pos) 549 { 550 icmp6_send(skb, ICMPV6_PARAMPROB, code, pos); 551 kfree_skb(skb); 552 } 553 554 static void icmpv6_echo_reply(struct sk_buff *skb) 555 { 556 struct net *net = dev_net(skb->dev); 557 struct sock *sk; 558 struct inet6_dev *idev; 559 struct ipv6_pinfo *np; 560 const struct in6_addr *saddr = NULL; 561 struct icmp6hdr *icmph = icmp6_hdr(skb); 562 struct icmp6hdr tmp_hdr; 563 struct flowi6 fl6; 564 struct icmpv6_msg msg; 565 struct dst_entry *dst; 566 int err = 0; 567 int hlimit; 568 u8 tclass; 569 u32 mark = IP6_REPLY_MARK(net, skb->mark); 570 struct sockcm_cookie sockc_unused = {0}; 571 572 saddr = &ipv6_hdr(skb)->daddr; 573 574 if (!ipv6_unicast_destination(skb) && 575 !(net->ipv6.sysctl.anycast_src_echo_reply && 576 ipv6_anycast_destination(skb_dst(skb), saddr))) 577 saddr = NULL; 578 579 memcpy(&tmp_hdr, icmph, sizeof(tmp_hdr)); 580 tmp_hdr.icmp6_type = ICMPV6_ECHO_REPLY; 581 582 memset(&fl6, 0, sizeof(fl6)); 583 fl6.flowi6_proto = IPPROTO_ICMPV6; 584 fl6.daddr = ipv6_hdr(skb)->saddr; 585 if (saddr) 586 fl6.saddr = *saddr; 587 fl6.flowi6_oif = l3mdev_fib_oif(skb->dev); 588 fl6.fl6_icmp_type = ICMPV6_ECHO_REPLY; 589 fl6.flowi6_mark = mark; 590 security_skb_classify_flow(skb, flowi6_to_flowi(&fl6)); 591 592 sk = icmpv6_xmit_lock(net); 593 if (!sk) 594 return; 595 sk->sk_mark = mark; 596 np = inet6_sk(sk); 597 598 if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr)) 599 fl6.flowi6_oif = np->mcast_oif; 600 else if (!fl6.flowi6_oif) 601 fl6.flowi6_oif = np->ucast_oif; 602 603 err = ip6_dst_lookup(net, sk, &dst, &fl6); 604 if (err) 605 goto out; 606 dst = xfrm_lookup(net, dst, flowi6_to_flowi(&fl6), sk, 0); 607 if (IS_ERR(dst)) 608 goto out; 609 610 hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst); 611 612 idev = __in6_dev_get(skb->dev); 613 614 msg.skb = skb; 615 msg.offset = 0; 616 msg.type = ICMPV6_ECHO_REPLY; 617 618 tclass = ipv6_get_dsfield(ipv6_hdr(skb)); 619 err = ip6_append_data(sk, icmpv6_getfrag, &msg, skb->len + sizeof(struct icmp6hdr), 620 sizeof(struct icmp6hdr), hlimit, tclass, NULL, &fl6, 621 (struct rt6_info *)dst, MSG_DONTWAIT, 622 np->dontfrag, &sockc_unused); 623 624 if (err) { 625 ICMP6_INC_STATS_BH(net, idev, ICMP6_MIB_OUTERRORS); 626 ip6_flush_pending_frames(sk); 627 } else { 628 err = icmpv6_push_pending_frames(sk, &fl6, &tmp_hdr, 629 skb->len + sizeof(struct icmp6hdr)); 630 } 631 dst_release(dst); 632 out: 633 icmpv6_xmit_unlock(sk); 634 } 635 636 void icmpv6_notify(struct sk_buff *skb, u8 type, u8 code, __be32 info) 637 { 638 const struct inet6_protocol *ipprot; 639 int inner_offset; 640 __be16 frag_off; 641 u8 nexthdr; 642 struct net *net = dev_net(skb->dev); 643 644 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr))) 645 goto out; 646 647 nexthdr = ((struct ipv6hdr *)skb->data)->nexthdr; 648 if (ipv6_ext_hdr(nexthdr)) { 649 /* now skip over extension headers */ 650 inner_offset = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), 651 &nexthdr, &frag_off); 652 if (inner_offset < 0) 653 goto out; 654 } else { 655 inner_offset = sizeof(struct ipv6hdr); 656 } 657 658 /* Checkin header including 8 bytes of inner protocol header. */ 659 if (!pskb_may_pull(skb, inner_offset+8)) 660 goto out; 661 662 /* BUGGG_FUTURE: we should try to parse exthdrs in this packet. 663 Without this we will not able f.e. to make source routed 664 pmtu discovery. 665 Corresponding argument (opt) to notifiers is already added. 666 --ANK (980726) 667 */ 668 669 ipprot = rcu_dereference(inet6_protos[nexthdr]); 670 if (ipprot && ipprot->err_handler) 671 ipprot->err_handler(skb, NULL, type, code, inner_offset, info); 672 673 raw6_icmp_error(skb, nexthdr, type, code, inner_offset, info); 674 return; 675 676 out: 677 ICMP6_INC_STATS_BH(net, __in6_dev_get(skb->dev), ICMP6_MIB_INERRORS); 678 } 679 680 /* 681 * Handle icmp messages 682 */ 683 684 static int icmpv6_rcv(struct sk_buff *skb) 685 { 686 struct net_device *dev = skb->dev; 687 struct inet6_dev *idev = __in6_dev_get(dev); 688 const struct in6_addr *saddr, *daddr; 689 struct icmp6hdr *hdr; 690 u8 type; 691 bool success = false; 692 693 if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) { 694 struct sec_path *sp = skb_sec_path(skb); 695 int nh; 696 697 if (!(sp && sp->xvec[sp->len - 1]->props.flags & 698 XFRM_STATE_ICMP)) 699 goto drop_no_count; 700 701 if (!pskb_may_pull(skb, sizeof(*hdr) + sizeof(struct ipv6hdr))) 702 goto drop_no_count; 703 704 nh = skb_network_offset(skb); 705 skb_set_network_header(skb, sizeof(*hdr)); 706 707 if (!xfrm6_policy_check_reverse(NULL, XFRM_POLICY_IN, skb)) 708 goto drop_no_count; 709 710 skb_set_network_header(skb, nh); 711 } 712 713 ICMP6_INC_STATS_BH(dev_net(dev), idev, ICMP6_MIB_INMSGS); 714 715 saddr = &ipv6_hdr(skb)->saddr; 716 daddr = &ipv6_hdr(skb)->daddr; 717 718 if (skb_checksum_validate(skb, IPPROTO_ICMPV6, ip6_compute_pseudo)) { 719 net_dbg_ratelimited("ICMPv6 checksum failed [%pI6c > %pI6c]\n", 720 saddr, daddr); 721 goto csum_error; 722 } 723 724 if (!pskb_pull(skb, sizeof(*hdr))) 725 goto discard_it; 726 727 hdr = icmp6_hdr(skb); 728 729 type = hdr->icmp6_type; 730 731 ICMP6MSGIN_INC_STATS_BH(dev_net(dev), idev, type); 732 733 switch (type) { 734 case ICMPV6_ECHO_REQUEST: 735 icmpv6_echo_reply(skb); 736 break; 737 738 case ICMPV6_ECHO_REPLY: 739 success = ping_rcv(skb); 740 break; 741 742 case ICMPV6_PKT_TOOBIG: 743 /* BUGGG_FUTURE: if packet contains rthdr, we cannot update 744 standard destination cache. Seems, only "advanced" 745 destination cache will allow to solve this problem 746 --ANK (980726) 747 */ 748 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr))) 749 goto discard_it; 750 hdr = icmp6_hdr(skb); 751 752 /* 753 * Drop through to notify 754 */ 755 756 case ICMPV6_DEST_UNREACH: 757 case ICMPV6_TIME_EXCEED: 758 case ICMPV6_PARAMPROB: 759 icmpv6_notify(skb, type, hdr->icmp6_code, hdr->icmp6_mtu); 760 break; 761 762 case NDISC_ROUTER_SOLICITATION: 763 case NDISC_ROUTER_ADVERTISEMENT: 764 case NDISC_NEIGHBOUR_SOLICITATION: 765 case NDISC_NEIGHBOUR_ADVERTISEMENT: 766 case NDISC_REDIRECT: 767 ndisc_rcv(skb); 768 break; 769 770 case ICMPV6_MGM_QUERY: 771 igmp6_event_query(skb); 772 break; 773 774 case ICMPV6_MGM_REPORT: 775 igmp6_event_report(skb); 776 break; 777 778 case ICMPV6_MGM_REDUCTION: 779 case ICMPV6_NI_QUERY: 780 case ICMPV6_NI_REPLY: 781 case ICMPV6_MLD2_REPORT: 782 case ICMPV6_DHAAD_REQUEST: 783 case ICMPV6_DHAAD_REPLY: 784 case ICMPV6_MOBILE_PREFIX_SOL: 785 case ICMPV6_MOBILE_PREFIX_ADV: 786 break; 787 788 default: 789 /* informational */ 790 if (type & ICMPV6_INFOMSG_MASK) 791 break; 792 793 net_dbg_ratelimited("icmpv6: msg of unknown type [%pI6c > %pI6c]\n", 794 saddr, daddr); 795 796 /* 797 * error of unknown type. 798 * must pass to upper level 799 */ 800 801 icmpv6_notify(skb, type, hdr->icmp6_code, hdr->icmp6_mtu); 802 } 803 804 /* until the v6 path can be better sorted assume failure and 805 * preserve the status quo behaviour for the rest of the paths to here 806 */ 807 if (success) 808 consume_skb(skb); 809 else 810 kfree_skb(skb); 811 812 return 0; 813 814 csum_error: 815 ICMP6_INC_STATS_BH(dev_net(dev), idev, ICMP6_MIB_CSUMERRORS); 816 discard_it: 817 ICMP6_INC_STATS_BH(dev_net(dev), idev, ICMP6_MIB_INERRORS); 818 drop_no_count: 819 kfree_skb(skb); 820 return 0; 821 } 822 823 void icmpv6_flow_init(struct sock *sk, struct flowi6 *fl6, 824 u8 type, 825 const struct in6_addr *saddr, 826 const struct in6_addr *daddr, 827 int oif) 828 { 829 memset(fl6, 0, sizeof(*fl6)); 830 fl6->saddr = *saddr; 831 fl6->daddr = *daddr; 832 fl6->flowi6_proto = IPPROTO_ICMPV6; 833 fl6->fl6_icmp_type = type; 834 fl6->fl6_icmp_code = 0; 835 fl6->flowi6_oif = oif; 836 security_sk_classify_flow(sk, flowi6_to_flowi(fl6)); 837 } 838 839 static int __net_init icmpv6_sk_init(struct net *net) 840 { 841 struct sock *sk; 842 int err, i, j; 843 844 net->ipv6.icmp_sk = 845 kzalloc(nr_cpu_ids * sizeof(struct sock *), GFP_KERNEL); 846 if (!net->ipv6.icmp_sk) 847 return -ENOMEM; 848 849 for_each_possible_cpu(i) { 850 err = inet_ctl_sock_create(&sk, PF_INET6, 851 SOCK_RAW, IPPROTO_ICMPV6, net); 852 if (err < 0) { 853 pr_err("Failed to initialize the ICMP6 control socket (err %d)\n", 854 err); 855 goto fail; 856 } 857 858 net->ipv6.icmp_sk[i] = sk; 859 860 /* Enough space for 2 64K ICMP packets, including 861 * sk_buff struct overhead. 862 */ 863 sk->sk_sndbuf = 2 * SKB_TRUESIZE(64 * 1024); 864 } 865 return 0; 866 867 fail: 868 for (j = 0; j < i; j++) 869 inet_ctl_sock_destroy(net->ipv6.icmp_sk[j]); 870 kfree(net->ipv6.icmp_sk); 871 return err; 872 } 873 874 static void __net_exit icmpv6_sk_exit(struct net *net) 875 { 876 int i; 877 878 for_each_possible_cpu(i) { 879 inet_ctl_sock_destroy(net->ipv6.icmp_sk[i]); 880 } 881 kfree(net->ipv6.icmp_sk); 882 } 883 884 static struct pernet_operations icmpv6_sk_ops = { 885 .init = icmpv6_sk_init, 886 .exit = icmpv6_sk_exit, 887 }; 888 889 int __init icmpv6_init(void) 890 { 891 int err; 892 893 err = register_pernet_subsys(&icmpv6_sk_ops); 894 if (err < 0) 895 return err; 896 897 err = -EAGAIN; 898 if (inet6_add_protocol(&icmpv6_protocol, IPPROTO_ICMPV6) < 0) 899 goto fail; 900 901 err = inet6_register_icmp_sender(icmp6_send); 902 if (err) 903 goto sender_reg_err; 904 return 0; 905 906 sender_reg_err: 907 inet6_del_protocol(&icmpv6_protocol, IPPROTO_ICMPV6); 908 fail: 909 pr_err("Failed to register ICMP6 protocol\n"); 910 unregister_pernet_subsys(&icmpv6_sk_ops); 911 return err; 912 } 913 914 void icmpv6_cleanup(void) 915 { 916 inet6_unregister_icmp_sender(icmp6_send); 917 unregister_pernet_subsys(&icmpv6_sk_ops); 918 inet6_del_protocol(&icmpv6_protocol, IPPROTO_ICMPV6); 919 } 920 921 922 static const struct icmp6_err { 923 int err; 924 int fatal; 925 } tab_unreach[] = { 926 { /* NOROUTE */ 927 .err = ENETUNREACH, 928 .fatal = 0, 929 }, 930 { /* ADM_PROHIBITED */ 931 .err = EACCES, 932 .fatal = 1, 933 }, 934 { /* Was NOT_NEIGHBOUR, now reserved */ 935 .err = EHOSTUNREACH, 936 .fatal = 0, 937 }, 938 { /* ADDR_UNREACH */ 939 .err = EHOSTUNREACH, 940 .fatal = 0, 941 }, 942 { /* PORT_UNREACH */ 943 .err = ECONNREFUSED, 944 .fatal = 1, 945 }, 946 { /* POLICY_FAIL */ 947 .err = EACCES, 948 .fatal = 1, 949 }, 950 { /* REJECT_ROUTE */ 951 .err = EACCES, 952 .fatal = 1, 953 }, 954 }; 955 956 int icmpv6_err_convert(u8 type, u8 code, int *err) 957 { 958 int fatal = 0; 959 960 *err = EPROTO; 961 962 switch (type) { 963 case ICMPV6_DEST_UNREACH: 964 fatal = 1; 965 if (code < ARRAY_SIZE(tab_unreach)) { 966 *err = tab_unreach[code].err; 967 fatal = tab_unreach[code].fatal; 968 } 969 break; 970 971 case ICMPV6_PKT_TOOBIG: 972 *err = EMSGSIZE; 973 break; 974 975 case ICMPV6_PARAMPROB: 976 *err = EPROTO; 977 fatal = 1; 978 break; 979 980 case ICMPV6_TIME_EXCEED: 981 *err = EHOSTUNREACH; 982 break; 983 } 984 985 return fatal; 986 } 987 EXPORT_SYMBOL(icmpv6_err_convert); 988 989 #ifdef CONFIG_SYSCTL 990 static struct ctl_table ipv6_icmp_table_template[] = { 991 { 992 .procname = "ratelimit", 993 .data = &init_net.ipv6.sysctl.icmpv6_time, 994 .maxlen = sizeof(int), 995 .mode = 0644, 996 .proc_handler = proc_dointvec_ms_jiffies, 997 }, 998 { }, 999 }; 1000 1001 struct ctl_table * __net_init ipv6_icmp_sysctl_init(struct net *net) 1002 { 1003 struct ctl_table *table; 1004 1005 table = kmemdup(ipv6_icmp_table_template, 1006 sizeof(ipv6_icmp_table_template), 1007 GFP_KERNEL); 1008 1009 if (table) 1010 table[0].data = &net->ipv6.sysctl.icmpv6_time; 1011 1012 return table; 1013 } 1014 #endif 1015