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 72 #include <asm/uaccess.h> 73 74 /* 75 * The ICMP socket(s). This is the most convenient way to flow control 76 * our ICMP output as well as maintain a clean interface throughout 77 * all layers. All Socketless IP sends will soon be gone. 78 * 79 * On SMP we have one ICMP socket per-cpu. 80 */ 81 static inline struct sock *icmpv6_sk(struct net *net) 82 { 83 return net->ipv6.icmp_sk[smp_processor_id()]; 84 } 85 86 static void icmpv6_err(struct sk_buff *skb, struct inet6_skb_parm *opt, 87 u8 type, u8 code, int offset, __be32 info) 88 { 89 /* icmpv6_notify checks 8 bytes can be pulled, icmp6hdr is 8 bytes */ 90 struct icmp6hdr *icmp6 = (struct icmp6hdr *) (skb->data + offset); 91 struct net *net = dev_net(skb->dev); 92 93 if (type == ICMPV6_PKT_TOOBIG) 94 ip6_update_pmtu(skb, net, info, 0, 0); 95 else if (type == NDISC_REDIRECT) 96 ip6_redirect(skb, net, skb->dev->ifindex, 0); 97 98 if (!(type & ICMPV6_INFOMSG_MASK)) 99 if (icmp6->icmp6_type == ICMPV6_ECHO_REQUEST) 100 ping_err(skb, offset, info); 101 } 102 103 static int icmpv6_rcv(struct sk_buff *skb); 104 105 static const struct inet6_protocol icmpv6_protocol = { 106 .handler = icmpv6_rcv, 107 .err_handler = icmpv6_err, 108 .flags = INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL, 109 }; 110 111 static __inline__ struct sock *icmpv6_xmit_lock(struct net *net) 112 { 113 struct sock *sk; 114 115 local_bh_disable(); 116 117 sk = icmpv6_sk(net); 118 if (unlikely(!spin_trylock(&sk->sk_lock.slock))) { 119 /* This can happen if the output path (f.e. SIT or 120 * ip6ip6 tunnel) signals dst_link_failure() for an 121 * outgoing ICMP6 packet. 122 */ 123 local_bh_enable(); 124 return NULL; 125 } 126 return sk; 127 } 128 129 static __inline__ void icmpv6_xmit_unlock(struct sock *sk) 130 { 131 spin_unlock_bh(&sk->sk_lock.slock); 132 } 133 134 /* 135 * Figure out, may we reply to this packet with icmp error. 136 * 137 * We do not reply, if: 138 * - it was icmp error message. 139 * - it is truncated, so that it is known, that protocol is ICMPV6 140 * (i.e. in the middle of some exthdr) 141 * 142 * --ANK (980726) 143 */ 144 145 static bool is_ineligible(const struct sk_buff *skb) 146 { 147 int ptr = (u8 *)(ipv6_hdr(skb) + 1) - skb->data; 148 int len = skb->len - ptr; 149 __u8 nexthdr = ipv6_hdr(skb)->nexthdr; 150 __be16 frag_off; 151 152 if (len < 0) 153 return true; 154 155 ptr = ipv6_skip_exthdr(skb, ptr, &nexthdr, &frag_off); 156 if (ptr < 0) 157 return false; 158 if (nexthdr == IPPROTO_ICMPV6) { 159 u8 _type, *tp; 160 tp = skb_header_pointer(skb, 161 ptr+offsetof(struct icmp6hdr, icmp6_type), 162 sizeof(_type), &_type); 163 if (tp == NULL || 164 !(*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 &rt->rt6i_dst.addr, 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 == NULL) 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 if ((skb = skb_peek(&sk->sk_write_queue)) == NULL) 247 goto out; 248 249 icmp6h = icmp6_hdr(skb); 250 memcpy(icmp6h, thdr, sizeof(struct icmp6hdr)); 251 icmp6h->icmp6_cksum = 0; 252 253 if (skb_queue_len(&sk->sk_write_queue) == 1) { 254 skb->csum = csum_partial(icmp6h, 255 sizeof(struct icmp6hdr), skb->csum); 256 icmp6h->icmp6_cksum = csum_ipv6_magic(&fl6->saddr, 257 &fl6->daddr, 258 len, fl6->flowi6_proto, 259 skb->csum); 260 } else { 261 __wsum tmp_csum = 0; 262 263 skb_queue_walk(&sk->sk_write_queue, skb) { 264 tmp_csum = csum_add(tmp_csum, skb->csum); 265 } 266 267 tmp_csum = csum_partial(icmp6h, 268 sizeof(struct icmp6hdr), tmp_csum); 269 icmp6h->icmp6_cksum = csum_ipv6_magic(&fl6->saddr, 270 &fl6->daddr, 271 len, fl6->flowi6_proto, 272 tmp_csum); 273 } 274 ip6_push_pending_frames(sk); 275 out: 276 return err; 277 } 278 279 struct icmpv6_msg { 280 struct sk_buff *skb; 281 int offset; 282 uint8_t type; 283 }; 284 285 static int icmpv6_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb) 286 { 287 struct icmpv6_msg *msg = (struct icmpv6_msg *) from; 288 struct sk_buff *org_skb = msg->skb; 289 __wsum csum = 0; 290 291 csum = skb_copy_and_csum_bits(org_skb, msg->offset + offset, 292 to, len, csum); 293 skb->csum = csum_block_add(skb->csum, csum, odd); 294 if (!(msg->type & ICMPV6_INFOMSG_MASK)) 295 nf_ct_attach(skb, org_skb); 296 return 0; 297 } 298 299 #if IS_ENABLED(CONFIG_IPV6_MIP6) 300 static void mip6_addr_swap(struct sk_buff *skb) 301 { 302 struct ipv6hdr *iph = ipv6_hdr(skb); 303 struct inet6_skb_parm *opt = IP6CB(skb); 304 struct ipv6_destopt_hao *hao; 305 struct in6_addr tmp; 306 int off; 307 308 if (opt->dsthao) { 309 off = ipv6_find_tlv(skb, opt->dsthao, IPV6_TLV_HAO); 310 if (likely(off >= 0)) { 311 hao = (struct ipv6_destopt_hao *) 312 (skb_network_header(skb) + off); 313 tmp = iph->saddr; 314 iph->saddr = hao->addr; 315 hao->addr = tmp; 316 } 317 } 318 } 319 #else 320 static inline void mip6_addr_swap(struct sk_buff *skb) {} 321 #endif 322 323 static struct dst_entry *icmpv6_route_lookup(struct net *net, 324 struct sk_buff *skb, 325 struct sock *sk, 326 struct flowi6 *fl6) 327 { 328 struct dst_entry *dst, *dst2; 329 struct flowi6 fl2; 330 int err; 331 332 err = ip6_dst_lookup(sk, &dst, fl6); 333 if (err) 334 return ERR_PTR(err); 335 336 /* 337 * We won't send icmp if the destination is known 338 * anycast. 339 */ 340 if (((struct rt6_info *)dst)->rt6i_flags & RTF_ANYCAST) { 341 LIMIT_NETDEBUG(KERN_DEBUG "icmp6_send: acast source\n"); 342 dst_release(dst); 343 return ERR_PTR(-EINVAL); 344 } 345 346 /* No need to clone since we're just using its address. */ 347 dst2 = dst; 348 349 dst = xfrm_lookup(net, dst, flowi6_to_flowi(fl6), sk, 0); 350 if (!IS_ERR(dst)) { 351 if (dst != dst2) 352 return dst; 353 } else { 354 if (PTR_ERR(dst) == -EPERM) 355 dst = NULL; 356 else 357 return dst; 358 } 359 360 err = xfrm_decode_session_reverse(skb, flowi6_to_flowi(&fl2), AF_INET6); 361 if (err) 362 goto relookup_failed; 363 364 err = ip6_dst_lookup(sk, &dst2, &fl2); 365 if (err) 366 goto relookup_failed; 367 368 dst2 = xfrm_lookup(net, dst2, flowi6_to_flowi(&fl2), sk, XFRM_LOOKUP_ICMP); 369 if (!IS_ERR(dst2)) { 370 dst_release(dst); 371 dst = dst2; 372 } else { 373 err = PTR_ERR(dst2); 374 if (err == -EPERM) { 375 dst_release(dst); 376 return dst2; 377 } else 378 goto relookup_failed; 379 } 380 381 relookup_failed: 382 if (dst) 383 return dst; 384 return ERR_PTR(err); 385 } 386 387 /* 388 * Send an ICMP message in response to a packet in error 389 */ 390 static void icmp6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info) 391 { 392 struct net *net = dev_net(skb->dev); 393 struct inet6_dev *idev = NULL; 394 struct ipv6hdr *hdr = ipv6_hdr(skb); 395 struct sock *sk; 396 struct ipv6_pinfo *np; 397 const struct in6_addr *saddr = NULL; 398 struct dst_entry *dst; 399 struct icmp6hdr tmp_hdr; 400 struct flowi6 fl6; 401 struct icmpv6_msg msg; 402 int iif = 0; 403 int addr_type = 0; 404 int len; 405 int hlimit; 406 int err = 0; 407 u32 mark = IP6_REPLY_MARK(net, skb->mark); 408 409 if ((u8 *)hdr < skb->head || 410 (skb_network_header(skb) + sizeof(*hdr)) > skb_tail_pointer(skb)) 411 return; 412 413 /* 414 * Make sure we respect the rules 415 * i.e. RFC 1885 2.4(e) 416 * Rule (e.1) is enforced by not using icmp6_send 417 * in any code that processes icmp errors. 418 */ 419 addr_type = ipv6_addr_type(&hdr->daddr); 420 421 if (ipv6_chk_addr(net, &hdr->daddr, skb->dev, 0) || 422 ipv6_chk_acast_addr_src(net, skb->dev, &hdr->daddr)) 423 saddr = &hdr->daddr; 424 425 /* 426 * Dest addr check 427 */ 428 429 if ((addr_type & IPV6_ADDR_MULTICAST || skb->pkt_type != PACKET_HOST)) { 430 if (type != ICMPV6_PKT_TOOBIG && 431 !(type == ICMPV6_PARAMPROB && 432 code == ICMPV6_UNK_OPTION && 433 (opt_unrec(skb, info)))) 434 return; 435 436 saddr = NULL; 437 } 438 439 addr_type = ipv6_addr_type(&hdr->saddr); 440 441 /* 442 * Source addr check 443 */ 444 445 if (__ipv6_addr_needs_scope_id(addr_type)) 446 iif = skb->dev->ifindex; 447 448 /* 449 * Must not send error if the source does not uniquely 450 * identify a single node (RFC2463 Section 2.4). 451 * We check unspecified / multicast addresses here, 452 * and anycast addresses will be checked later. 453 */ 454 if ((addr_type == IPV6_ADDR_ANY) || (addr_type & IPV6_ADDR_MULTICAST)) { 455 LIMIT_NETDEBUG(KERN_DEBUG "icmp6_send: addr_any/mcast source\n"); 456 return; 457 } 458 459 /* 460 * Never answer to a ICMP packet. 461 */ 462 if (is_ineligible(skb)) { 463 LIMIT_NETDEBUG(KERN_DEBUG "icmp6_send: no reply to icmp error\n"); 464 return; 465 } 466 467 mip6_addr_swap(skb); 468 469 memset(&fl6, 0, sizeof(fl6)); 470 fl6.flowi6_proto = IPPROTO_ICMPV6; 471 fl6.daddr = hdr->saddr; 472 if (saddr) 473 fl6.saddr = *saddr; 474 fl6.flowi6_mark = mark; 475 fl6.flowi6_oif = iif; 476 fl6.fl6_icmp_type = type; 477 fl6.fl6_icmp_code = code; 478 security_skb_classify_flow(skb, flowi6_to_flowi(&fl6)); 479 480 sk = icmpv6_xmit_lock(net); 481 if (sk == NULL) 482 return; 483 sk->sk_mark = mark; 484 np = inet6_sk(sk); 485 486 if (!icmpv6_xrlim_allow(sk, type, &fl6)) 487 goto out; 488 489 tmp_hdr.icmp6_type = type; 490 tmp_hdr.icmp6_code = code; 491 tmp_hdr.icmp6_cksum = 0; 492 tmp_hdr.icmp6_pointer = htonl(info); 493 494 if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr)) 495 fl6.flowi6_oif = np->mcast_oif; 496 else if (!fl6.flowi6_oif) 497 fl6.flowi6_oif = np->ucast_oif; 498 499 dst = icmpv6_route_lookup(net, skb, sk, &fl6); 500 if (IS_ERR(dst)) 501 goto out; 502 503 hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst); 504 505 msg.skb = skb; 506 msg.offset = skb_network_offset(skb); 507 msg.type = type; 508 509 len = skb->len - msg.offset; 510 len = min_t(unsigned int, len, IPV6_MIN_MTU - sizeof(struct ipv6hdr) - sizeof(struct icmp6hdr)); 511 if (len < 0) { 512 LIMIT_NETDEBUG(KERN_DEBUG "icmp: len problem\n"); 513 goto out_dst_release; 514 } 515 516 rcu_read_lock(); 517 idev = __in6_dev_get(skb->dev); 518 519 err = ip6_append_data(sk, icmpv6_getfrag, &msg, 520 len + sizeof(struct icmp6hdr), 521 sizeof(struct icmp6hdr), hlimit, 522 np->tclass, NULL, &fl6, (struct rt6_info *)dst, 523 MSG_DONTWAIT, np->dontfrag); 524 if (err) { 525 ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTERRORS); 526 ip6_flush_pending_frames(sk); 527 } else { 528 err = icmpv6_push_pending_frames(sk, &fl6, &tmp_hdr, 529 len + sizeof(struct icmp6hdr)); 530 } 531 rcu_read_unlock(); 532 out_dst_release: 533 dst_release(dst); 534 out: 535 icmpv6_xmit_unlock(sk); 536 } 537 538 /* Slightly more convenient version of icmp6_send. 539 */ 540 void icmpv6_param_prob(struct sk_buff *skb, u8 code, int pos) 541 { 542 icmp6_send(skb, ICMPV6_PARAMPROB, code, pos); 543 kfree_skb(skb); 544 } 545 546 static void icmpv6_echo_reply(struct sk_buff *skb) 547 { 548 struct net *net = dev_net(skb->dev); 549 struct sock *sk; 550 struct inet6_dev *idev; 551 struct ipv6_pinfo *np; 552 const struct in6_addr *saddr = NULL; 553 struct icmp6hdr *icmph = icmp6_hdr(skb); 554 struct icmp6hdr tmp_hdr; 555 struct flowi6 fl6; 556 struct icmpv6_msg msg; 557 struct dst_entry *dst; 558 int err = 0; 559 int hlimit; 560 u8 tclass; 561 u32 mark = IP6_REPLY_MARK(net, skb->mark); 562 563 saddr = &ipv6_hdr(skb)->daddr; 564 565 if (!ipv6_unicast_destination(skb) && 566 !(net->ipv6.sysctl.anycast_src_echo_reply && 567 ipv6_anycast_destination(skb))) 568 saddr = NULL; 569 570 memcpy(&tmp_hdr, icmph, sizeof(tmp_hdr)); 571 tmp_hdr.icmp6_type = ICMPV6_ECHO_REPLY; 572 573 memset(&fl6, 0, sizeof(fl6)); 574 fl6.flowi6_proto = IPPROTO_ICMPV6; 575 fl6.daddr = ipv6_hdr(skb)->saddr; 576 if (saddr) 577 fl6.saddr = *saddr; 578 fl6.flowi6_oif = skb->dev->ifindex; 579 fl6.fl6_icmp_type = ICMPV6_ECHO_REPLY; 580 fl6.flowi6_mark = mark; 581 security_skb_classify_flow(skb, flowi6_to_flowi(&fl6)); 582 583 sk = icmpv6_xmit_lock(net); 584 if (sk == NULL) 585 return; 586 sk->sk_mark = mark; 587 np = inet6_sk(sk); 588 589 if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr)) 590 fl6.flowi6_oif = np->mcast_oif; 591 else if (!fl6.flowi6_oif) 592 fl6.flowi6_oif = np->ucast_oif; 593 594 err = ip6_dst_lookup(sk, &dst, &fl6); 595 if (err) 596 goto out; 597 dst = xfrm_lookup(net, dst, flowi6_to_flowi(&fl6), sk, 0); 598 if (IS_ERR(dst)) 599 goto out; 600 601 hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst); 602 603 idev = __in6_dev_get(skb->dev); 604 605 msg.skb = skb; 606 msg.offset = 0; 607 msg.type = ICMPV6_ECHO_REPLY; 608 609 tclass = ipv6_get_dsfield(ipv6_hdr(skb)); 610 err = ip6_append_data(sk, icmpv6_getfrag, &msg, skb->len + sizeof(struct icmp6hdr), 611 sizeof(struct icmp6hdr), hlimit, tclass, NULL, &fl6, 612 (struct rt6_info *)dst, MSG_DONTWAIT, 613 np->dontfrag); 614 615 if (err) { 616 ICMP6_INC_STATS_BH(net, idev, ICMP6_MIB_OUTERRORS); 617 ip6_flush_pending_frames(sk); 618 } else { 619 err = icmpv6_push_pending_frames(sk, &fl6, &tmp_hdr, 620 skb->len + sizeof(struct icmp6hdr)); 621 } 622 dst_release(dst); 623 out: 624 icmpv6_xmit_unlock(sk); 625 } 626 627 void icmpv6_notify(struct sk_buff *skb, u8 type, u8 code, __be32 info) 628 { 629 const struct inet6_protocol *ipprot; 630 int inner_offset; 631 __be16 frag_off; 632 u8 nexthdr; 633 struct net *net = dev_net(skb->dev); 634 635 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr))) 636 goto out; 637 638 nexthdr = ((struct ipv6hdr *)skb->data)->nexthdr; 639 if (ipv6_ext_hdr(nexthdr)) { 640 /* now skip over extension headers */ 641 inner_offset = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), 642 &nexthdr, &frag_off); 643 if (inner_offset < 0) 644 goto out; 645 } else { 646 inner_offset = sizeof(struct ipv6hdr); 647 } 648 649 /* Checkin header including 8 bytes of inner protocol header. */ 650 if (!pskb_may_pull(skb, inner_offset+8)) 651 goto out; 652 653 /* BUGGG_FUTURE: we should try to parse exthdrs in this packet. 654 Without this we will not able f.e. to make source routed 655 pmtu discovery. 656 Corresponding argument (opt) to notifiers is already added. 657 --ANK (980726) 658 */ 659 660 ipprot = rcu_dereference(inet6_protos[nexthdr]); 661 if (ipprot && ipprot->err_handler) 662 ipprot->err_handler(skb, NULL, type, code, inner_offset, info); 663 664 raw6_icmp_error(skb, nexthdr, type, code, inner_offset, info); 665 return; 666 667 out: 668 ICMP6_INC_STATS_BH(net, __in6_dev_get(skb->dev), ICMP6_MIB_INERRORS); 669 } 670 671 /* 672 * Handle icmp messages 673 */ 674 675 static int icmpv6_rcv(struct sk_buff *skb) 676 { 677 struct net_device *dev = skb->dev; 678 struct inet6_dev *idev = __in6_dev_get(dev); 679 const struct in6_addr *saddr, *daddr; 680 struct icmp6hdr *hdr; 681 u8 type; 682 683 if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) { 684 struct sec_path *sp = skb_sec_path(skb); 685 int nh; 686 687 if (!(sp && sp->xvec[sp->len - 1]->props.flags & 688 XFRM_STATE_ICMP)) 689 goto drop_no_count; 690 691 if (!pskb_may_pull(skb, sizeof(*hdr) + sizeof(struct ipv6hdr))) 692 goto drop_no_count; 693 694 nh = skb_network_offset(skb); 695 skb_set_network_header(skb, sizeof(*hdr)); 696 697 if (!xfrm6_policy_check_reverse(NULL, XFRM_POLICY_IN, skb)) 698 goto drop_no_count; 699 700 skb_set_network_header(skb, nh); 701 } 702 703 ICMP6_INC_STATS_BH(dev_net(dev), idev, ICMP6_MIB_INMSGS); 704 705 saddr = &ipv6_hdr(skb)->saddr; 706 daddr = &ipv6_hdr(skb)->daddr; 707 708 if (skb_checksum_validate(skb, IPPROTO_ICMPV6, ip6_compute_pseudo)) { 709 LIMIT_NETDEBUG(KERN_DEBUG 710 "ICMPv6 checksum failed [%pI6c > %pI6c]\n", 711 saddr, daddr); 712 goto csum_error; 713 } 714 715 if (!pskb_pull(skb, sizeof(*hdr))) 716 goto discard_it; 717 718 hdr = icmp6_hdr(skb); 719 720 type = hdr->icmp6_type; 721 722 ICMP6MSGIN_INC_STATS_BH(dev_net(dev), idev, type); 723 724 switch (type) { 725 case ICMPV6_ECHO_REQUEST: 726 icmpv6_echo_reply(skb); 727 break; 728 729 case ICMPV6_ECHO_REPLY: 730 ping_rcv(skb); 731 break; 732 733 case ICMPV6_PKT_TOOBIG: 734 /* BUGGG_FUTURE: if packet contains rthdr, we cannot update 735 standard destination cache. Seems, only "advanced" 736 destination cache will allow to solve this problem 737 --ANK (980726) 738 */ 739 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr))) 740 goto discard_it; 741 hdr = icmp6_hdr(skb); 742 743 /* 744 * Drop through to notify 745 */ 746 747 case ICMPV6_DEST_UNREACH: 748 case ICMPV6_TIME_EXCEED: 749 case ICMPV6_PARAMPROB: 750 icmpv6_notify(skb, type, hdr->icmp6_code, hdr->icmp6_mtu); 751 break; 752 753 case NDISC_ROUTER_SOLICITATION: 754 case NDISC_ROUTER_ADVERTISEMENT: 755 case NDISC_NEIGHBOUR_SOLICITATION: 756 case NDISC_NEIGHBOUR_ADVERTISEMENT: 757 case NDISC_REDIRECT: 758 ndisc_rcv(skb); 759 break; 760 761 case ICMPV6_MGM_QUERY: 762 igmp6_event_query(skb); 763 break; 764 765 case ICMPV6_MGM_REPORT: 766 igmp6_event_report(skb); 767 break; 768 769 case ICMPV6_MGM_REDUCTION: 770 case ICMPV6_NI_QUERY: 771 case ICMPV6_NI_REPLY: 772 case ICMPV6_MLD2_REPORT: 773 case ICMPV6_DHAAD_REQUEST: 774 case ICMPV6_DHAAD_REPLY: 775 case ICMPV6_MOBILE_PREFIX_SOL: 776 case ICMPV6_MOBILE_PREFIX_ADV: 777 break; 778 779 default: 780 LIMIT_NETDEBUG(KERN_DEBUG "icmpv6: msg of unknown type\n"); 781 782 /* informational */ 783 if (type & ICMPV6_INFOMSG_MASK) 784 break; 785 786 /* 787 * error of unknown type. 788 * must pass to upper level 789 */ 790 791 icmpv6_notify(skb, type, hdr->icmp6_code, hdr->icmp6_mtu); 792 } 793 794 kfree_skb(skb); 795 return 0; 796 797 csum_error: 798 ICMP6_INC_STATS_BH(dev_net(dev), idev, ICMP6_MIB_CSUMERRORS); 799 discard_it: 800 ICMP6_INC_STATS_BH(dev_net(dev), idev, ICMP6_MIB_INERRORS); 801 drop_no_count: 802 kfree_skb(skb); 803 return 0; 804 } 805 806 void icmpv6_flow_init(struct sock *sk, struct flowi6 *fl6, 807 u8 type, 808 const struct in6_addr *saddr, 809 const struct in6_addr *daddr, 810 int oif) 811 { 812 memset(fl6, 0, sizeof(*fl6)); 813 fl6->saddr = *saddr; 814 fl6->daddr = *daddr; 815 fl6->flowi6_proto = IPPROTO_ICMPV6; 816 fl6->fl6_icmp_type = type; 817 fl6->fl6_icmp_code = 0; 818 fl6->flowi6_oif = oif; 819 security_sk_classify_flow(sk, flowi6_to_flowi(fl6)); 820 } 821 822 /* 823 * Special lock-class for __icmpv6_sk: 824 */ 825 static struct lock_class_key icmpv6_socket_sk_dst_lock_key; 826 827 static int __net_init icmpv6_sk_init(struct net *net) 828 { 829 struct sock *sk; 830 int err, i, j; 831 832 net->ipv6.icmp_sk = 833 kzalloc(nr_cpu_ids * sizeof(struct sock *), GFP_KERNEL); 834 if (net->ipv6.icmp_sk == NULL) 835 return -ENOMEM; 836 837 for_each_possible_cpu(i) { 838 err = inet_ctl_sock_create(&sk, PF_INET6, 839 SOCK_RAW, IPPROTO_ICMPV6, net); 840 if (err < 0) { 841 pr_err("Failed to initialize the ICMP6 control socket (err %d)\n", 842 err); 843 goto fail; 844 } 845 846 net->ipv6.icmp_sk[i] = sk; 847 848 /* 849 * Split off their lock-class, because sk->sk_dst_lock 850 * gets used from softirqs, which is safe for 851 * __icmpv6_sk (because those never get directly used 852 * via userspace syscalls), but unsafe for normal sockets. 853 */ 854 lockdep_set_class(&sk->sk_dst_lock, 855 &icmpv6_socket_sk_dst_lock_key); 856 857 /* Enough space for 2 64K ICMP packets, including 858 * sk_buff struct overhead. 859 */ 860 sk->sk_sndbuf = 2 * SKB_TRUESIZE(64 * 1024); 861 } 862 return 0; 863 864 fail: 865 for (j = 0; j < i; j++) 866 inet_ctl_sock_destroy(net->ipv6.icmp_sk[j]); 867 kfree(net->ipv6.icmp_sk); 868 return err; 869 } 870 871 static void __net_exit icmpv6_sk_exit(struct net *net) 872 { 873 int i; 874 875 for_each_possible_cpu(i) { 876 inet_ctl_sock_destroy(net->ipv6.icmp_sk[i]); 877 } 878 kfree(net->ipv6.icmp_sk); 879 } 880 881 static struct pernet_operations icmpv6_sk_ops = { 882 .init = icmpv6_sk_init, 883 .exit = icmpv6_sk_exit, 884 }; 885 886 int __init icmpv6_init(void) 887 { 888 int err; 889 890 err = register_pernet_subsys(&icmpv6_sk_ops); 891 if (err < 0) 892 return err; 893 894 err = -EAGAIN; 895 if (inet6_add_protocol(&icmpv6_protocol, IPPROTO_ICMPV6) < 0) 896 goto fail; 897 898 err = inet6_register_icmp_sender(icmp6_send); 899 if (err) 900 goto sender_reg_err; 901 return 0; 902 903 sender_reg_err: 904 inet6_del_protocol(&icmpv6_protocol, IPPROTO_ICMPV6); 905 fail: 906 pr_err("Failed to register ICMP6 protocol\n"); 907 unregister_pernet_subsys(&icmpv6_sk_ops); 908 return err; 909 } 910 911 void icmpv6_cleanup(void) 912 { 913 inet6_unregister_icmp_sender(icmp6_send); 914 unregister_pernet_subsys(&icmpv6_sk_ops); 915 inet6_del_protocol(&icmpv6_protocol, IPPROTO_ICMPV6); 916 } 917 918 919 static const struct icmp6_err { 920 int err; 921 int fatal; 922 } tab_unreach[] = { 923 { /* NOROUTE */ 924 .err = ENETUNREACH, 925 .fatal = 0, 926 }, 927 { /* ADM_PROHIBITED */ 928 .err = EACCES, 929 .fatal = 1, 930 }, 931 { /* Was NOT_NEIGHBOUR, now reserved */ 932 .err = EHOSTUNREACH, 933 .fatal = 0, 934 }, 935 { /* ADDR_UNREACH */ 936 .err = EHOSTUNREACH, 937 .fatal = 0, 938 }, 939 { /* PORT_UNREACH */ 940 .err = ECONNREFUSED, 941 .fatal = 1, 942 }, 943 { /* POLICY_FAIL */ 944 .err = EACCES, 945 .fatal = 1, 946 }, 947 { /* REJECT_ROUTE */ 948 .err = EACCES, 949 .fatal = 1, 950 }, 951 }; 952 953 int icmpv6_err_convert(u8 type, u8 code, int *err) 954 { 955 int fatal = 0; 956 957 *err = EPROTO; 958 959 switch (type) { 960 case ICMPV6_DEST_UNREACH: 961 fatal = 1; 962 if (code < ARRAY_SIZE(tab_unreach)) { 963 *err = tab_unreach[code].err; 964 fatal = tab_unreach[code].fatal; 965 } 966 break; 967 968 case ICMPV6_PKT_TOOBIG: 969 *err = EMSGSIZE; 970 break; 971 972 case ICMPV6_PARAMPROB: 973 *err = EPROTO; 974 fatal = 1; 975 break; 976 977 case ICMPV6_TIME_EXCEED: 978 *err = EHOSTUNREACH; 979 break; 980 } 981 982 return fatal; 983 } 984 EXPORT_SYMBOL(icmpv6_err_convert); 985 986 #ifdef CONFIG_SYSCTL 987 static struct ctl_table ipv6_icmp_table_template[] = { 988 { 989 .procname = "ratelimit", 990 .data = &init_net.ipv6.sysctl.icmpv6_time, 991 .maxlen = sizeof(int), 992 .mode = 0644, 993 .proc_handler = proc_dointvec_ms_jiffies, 994 }, 995 { }, 996 }; 997 998 struct ctl_table * __net_init ipv6_icmp_sysctl_init(struct net *net) 999 { 1000 struct ctl_table *table; 1001 1002 table = kmemdup(ipv6_icmp_table_template, 1003 sizeof(ipv6_icmp_table_template), 1004 GFP_KERNEL); 1005 1006 if (table) 1007 table[0].data = &net->ipv6.sysctl.icmpv6_time; 1008 1009 return table; 1010 } 1011 #endif 1012 1013