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 inline bool icmpv6_xrlim_allow(struct sock *sk, u8 type, 174 struct flowi6 *fl6) 175 { 176 struct dst_entry *dst; 177 struct net *net = sock_net(sk); 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 struct inet_peer *peer; 203 204 /* Give more bandwidth to wider prefixes. */ 205 if (rt->rt6i_dst.plen < 128) 206 tmo >>= ((128 - rt->rt6i_dst.plen)>>5); 207 208 peer = inet_getpeer_v6(net->ipv6.peers, &rt->rt6i_dst.addr, 1); 209 res = inet_peer_xrlim_allow(peer, tmo); 210 if (peer) 211 inet_putpeer(peer); 212 } 213 dst_release(dst); 214 return res; 215 } 216 217 /* 218 * an inline helper for the "simple" if statement below 219 * checks if parameter problem report is caused by an 220 * unrecognized IPv6 option that has the Option Type 221 * highest-order two bits set to 10 222 */ 223 224 static bool opt_unrec(struct sk_buff *skb, __u32 offset) 225 { 226 u8 _optval, *op; 227 228 offset += skb_network_offset(skb); 229 op = skb_header_pointer(skb, offset, sizeof(_optval), &_optval); 230 if (op == NULL) 231 return true; 232 return (*op & 0xC0) == 0x80; 233 } 234 235 int icmpv6_push_pending_frames(struct sock *sk, struct flowi6 *fl6, 236 struct icmp6hdr *thdr, int len) 237 { 238 struct sk_buff *skb; 239 struct icmp6hdr *icmp6h; 240 int err = 0; 241 242 if ((skb = skb_peek(&sk->sk_write_queue)) == NULL) 243 goto out; 244 245 icmp6h = icmp6_hdr(skb); 246 memcpy(icmp6h, thdr, sizeof(struct icmp6hdr)); 247 icmp6h->icmp6_cksum = 0; 248 249 if (skb_queue_len(&sk->sk_write_queue) == 1) { 250 skb->csum = csum_partial(icmp6h, 251 sizeof(struct icmp6hdr), skb->csum); 252 icmp6h->icmp6_cksum = csum_ipv6_magic(&fl6->saddr, 253 &fl6->daddr, 254 len, fl6->flowi6_proto, 255 skb->csum); 256 } else { 257 __wsum tmp_csum = 0; 258 259 skb_queue_walk(&sk->sk_write_queue, skb) { 260 tmp_csum = csum_add(tmp_csum, skb->csum); 261 } 262 263 tmp_csum = csum_partial(icmp6h, 264 sizeof(struct icmp6hdr), tmp_csum); 265 icmp6h->icmp6_cksum = csum_ipv6_magic(&fl6->saddr, 266 &fl6->daddr, 267 len, fl6->flowi6_proto, 268 tmp_csum); 269 } 270 ip6_push_pending_frames(sk); 271 out: 272 return err; 273 } 274 275 struct icmpv6_msg { 276 struct sk_buff *skb; 277 int offset; 278 uint8_t type; 279 }; 280 281 static int icmpv6_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb) 282 { 283 struct icmpv6_msg *msg = (struct icmpv6_msg *) from; 284 struct sk_buff *org_skb = msg->skb; 285 __wsum csum = 0; 286 287 csum = skb_copy_and_csum_bits(org_skb, msg->offset + offset, 288 to, len, csum); 289 skb->csum = csum_block_add(skb->csum, csum, odd); 290 if (!(msg->type & ICMPV6_INFOMSG_MASK)) 291 nf_ct_attach(skb, org_skb); 292 return 0; 293 } 294 295 #if IS_ENABLED(CONFIG_IPV6_MIP6) 296 static void mip6_addr_swap(struct sk_buff *skb) 297 { 298 struct ipv6hdr *iph = ipv6_hdr(skb); 299 struct inet6_skb_parm *opt = IP6CB(skb); 300 struct ipv6_destopt_hao *hao; 301 struct in6_addr tmp; 302 int off; 303 304 if (opt->dsthao) { 305 off = ipv6_find_tlv(skb, opt->dsthao, IPV6_TLV_HAO); 306 if (likely(off >= 0)) { 307 hao = (struct ipv6_destopt_hao *) 308 (skb_network_header(skb) + off); 309 tmp = iph->saddr; 310 iph->saddr = hao->addr; 311 hao->addr = tmp; 312 } 313 } 314 } 315 #else 316 static inline void mip6_addr_swap(struct sk_buff *skb) {} 317 #endif 318 319 static struct dst_entry *icmpv6_route_lookup(struct net *net, 320 struct sk_buff *skb, 321 struct sock *sk, 322 struct flowi6 *fl6) 323 { 324 struct dst_entry *dst, *dst2; 325 struct flowi6 fl2; 326 int err; 327 328 err = ip6_dst_lookup(sk, &dst, fl6); 329 if (err) 330 return ERR_PTR(err); 331 332 /* 333 * We won't send icmp if the destination is known 334 * anycast. 335 */ 336 if (((struct rt6_info *)dst)->rt6i_flags & RTF_ANYCAST) { 337 LIMIT_NETDEBUG(KERN_DEBUG "icmp6_send: acast source\n"); 338 dst_release(dst); 339 return ERR_PTR(-EINVAL); 340 } 341 342 /* No need to clone since we're just using its address. */ 343 dst2 = dst; 344 345 dst = xfrm_lookup(net, dst, flowi6_to_flowi(fl6), sk, 0); 346 if (!IS_ERR(dst)) { 347 if (dst != dst2) 348 return dst; 349 } else { 350 if (PTR_ERR(dst) == -EPERM) 351 dst = NULL; 352 else 353 return dst; 354 } 355 356 err = xfrm_decode_session_reverse(skb, flowi6_to_flowi(&fl2), AF_INET6); 357 if (err) 358 goto relookup_failed; 359 360 err = ip6_dst_lookup(sk, &dst2, &fl2); 361 if (err) 362 goto relookup_failed; 363 364 dst2 = xfrm_lookup(net, dst2, flowi6_to_flowi(&fl2), sk, XFRM_LOOKUP_ICMP); 365 if (!IS_ERR(dst2)) { 366 dst_release(dst); 367 dst = dst2; 368 } else { 369 err = PTR_ERR(dst2); 370 if (err == -EPERM) { 371 dst_release(dst); 372 return dst2; 373 } else 374 goto relookup_failed; 375 } 376 377 relookup_failed: 378 if (dst) 379 return dst; 380 return ERR_PTR(err); 381 } 382 383 /* 384 * Send an ICMP message in response to a packet in error 385 */ 386 static void icmp6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info) 387 { 388 struct net *net = dev_net(skb->dev); 389 struct inet6_dev *idev = NULL; 390 struct ipv6hdr *hdr = ipv6_hdr(skb); 391 struct sock *sk; 392 struct ipv6_pinfo *np; 393 const struct in6_addr *saddr = NULL; 394 struct dst_entry *dst; 395 struct icmp6hdr tmp_hdr; 396 struct flowi6 fl6; 397 struct icmpv6_msg msg; 398 int iif = 0; 399 int addr_type = 0; 400 int len; 401 int hlimit; 402 int err = 0; 403 404 if ((u8 *)hdr < skb->head || 405 (skb_network_header(skb) + sizeof(*hdr)) > skb_tail_pointer(skb)) 406 return; 407 408 /* 409 * Make sure we respect the rules 410 * i.e. RFC 1885 2.4(e) 411 * Rule (e.1) is enforced by not using icmp6_send 412 * in any code that processes icmp errors. 413 */ 414 addr_type = ipv6_addr_type(&hdr->daddr); 415 416 if (ipv6_chk_addr(net, &hdr->daddr, skb->dev, 0)) 417 saddr = &hdr->daddr; 418 419 /* 420 * Dest addr check 421 */ 422 423 if ((addr_type & IPV6_ADDR_MULTICAST || skb->pkt_type != PACKET_HOST)) { 424 if (type != ICMPV6_PKT_TOOBIG && 425 !(type == ICMPV6_PARAMPROB && 426 code == ICMPV6_UNK_OPTION && 427 (opt_unrec(skb, info)))) 428 return; 429 430 saddr = NULL; 431 } 432 433 addr_type = ipv6_addr_type(&hdr->saddr); 434 435 /* 436 * Source addr check 437 */ 438 439 if (__ipv6_addr_needs_scope_id(addr_type)) 440 iif = skb->dev->ifindex; 441 442 /* 443 * Must not send error if the source does not uniquely 444 * identify a single node (RFC2463 Section 2.4). 445 * We check unspecified / multicast addresses here, 446 * and anycast addresses will be checked later. 447 */ 448 if ((addr_type == IPV6_ADDR_ANY) || (addr_type & IPV6_ADDR_MULTICAST)) { 449 LIMIT_NETDEBUG(KERN_DEBUG "icmp6_send: addr_any/mcast source\n"); 450 return; 451 } 452 453 /* 454 * Never answer to a ICMP packet. 455 */ 456 if (is_ineligible(skb)) { 457 LIMIT_NETDEBUG(KERN_DEBUG "icmp6_send: no reply to icmp error\n"); 458 return; 459 } 460 461 mip6_addr_swap(skb); 462 463 memset(&fl6, 0, sizeof(fl6)); 464 fl6.flowi6_proto = IPPROTO_ICMPV6; 465 fl6.daddr = hdr->saddr; 466 if (saddr) 467 fl6.saddr = *saddr; 468 fl6.flowi6_oif = iif; 469 fl6.fl6_icmp_type = type; 470 fl6.fl6_icmp_code = code; 471 security_skb_classify_flow(skb, flowi6_to_flowi(&fl6)); 472 473 sk = icmpv6_xmit_lock(net); 474 if (sk == NULL) 475 return; 476 np = inet6_sk(sk); 477 478 if (!icmpv6_xrlim_allow(sk, type, &fl6)) 479 goto out; 480 481 tmp_hdr.icmp6_type = type; 482 tmp_hdr.icmp6_code = code; 483 tmp_hdr.icmp6_cksum = 0; 484 tmp_hdr.icmp6_pointer = htonl(info); 485 486 if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr)) 487 fl6.flowi6_oif = np->mcast_oif; 488 else if (!fl6.flowi6_oif) 489 fl6.flowi6_oif = np->ucast_oif; 490 491 dst = icmpv6_route_lookup(net, skb, sk, &fl6); 492 if (IS_ERR(dst)) 493 goto out; 494 495 if (ipv6_addr_is_multicast(&fl6.daddr)) 496 hlimit = np->mcast_hops; 497 else 498 hlimit = np->hop_limit; 499 if (hlimit < 0) 500 hlimit = ip6_dst_hoplimit(dst); 501 502 msg.skb = skb; 503 msg.offset = skb_network_offset(skb); 504 msg.type = type; 505 506 len = skb->len - msg.offset; 507 len = min_t(unsigned int, len, IPV6_MIN_MTU - sizeof(struct ipv6hdr) -sizeof(struct icmp6hdr)); 508 if (len < 0) { 509 LIMIT_NETDEBUG(KERN_DEBUG "icmp: len problem\n"); 510 goto out_dst_release; 511 } 512 513 rcu_read_lock(); 514 idev = __in6_dev_get(skb->dev); 515 516 err = ip6_append_data(sk, icmpv6_getfrag, &msg, 517 len + sizeof(struct icmp6hdr), 518 sizeof(struct icmp6hdr), hlimit, 519 np->tclass, NULL, &fl6, (struct rt6_info *)dst, 520 MSG_DONTWAIT, np->dontfrag); 521 if (err) { 522 ICMP6_INC_STATS_BH(net, idev, ICMP6_MIB_OUTERRORS); 523 ip6_flush_pending_frames(sk); 524 } else { 525 err = icmpv6_push_pending_frames(sk, &fl6, &tmp_hdr, 526 len + sizeof(struct icmp6hdr)); 527 } 528 rcu_read_unlock(); 529 out_dst_release: 530 dst_release(dst); 531 out: 532 icmpv6_xmit_unlock(sk); 533 } 534 535 /* Slightly more convenient version of icmp6_send. 536 */ 537 void icmpv6_param_prob(struct sk_buff *skb, u8 code, int pos) 538 { 539 icmp6_send(skb, ICMPV6_PARAMPROB, code, pos); 540 kfree_skb(skb); 541 } 542 543 static void icmpv6_echo_reply(struct sk_buff *skb) 544 { 545 struct net *net = dev_net(skb->dev); 546 struct sock *sk; 547 struct inet6_dev *idev; 548 struct ipv6_pinfo *np; 549 const struct in6_addr *saddr = NULL; 550 struct icmp6hdr *icmph = icmp6_hdr(skb); 551 struct icmp6hdr tmp_hdr; 552 struct flowi6 fl6; 553 struct icmpv6_msg msg; 554 struct dst_entry *dst; 555 int err = 0; 556 int hlimit; 557 u8 tclass; 558 559 saddr = &ipv6_hdr(skb)->daddr; 560 561 if (!ipv6_unicast_destination(skb) && 562 !(net->ipv6.sysctl.anycast_src_echo_reply && 563 ipv6_anycast_destination(skb))) 564 saddr = NULL; 565 566 memcpy(&tmp_hdr, icmph, sizeof(tmp_hdr)); 567 tmp_hdr.icmp6_type = ICMPV6_ECHO_REPLY; 568 569 memset(&fl6, 0, sizeof(fl6)); 570 fl6.flowi6_proto = IPPROTO_ICMPV6; 571 fl6.daddr = ipv6_hdr(skb)->saddr; 572 if (saddr) 573 fl6.saddr = *saddr; 574 fl6.flowi6_oif = skb->dev->ifindex; 575 fl6.fl6_icmp_type = ICMPV6_ECHO_REPLY; 576 security_skb_classify_flow(skb, flowi6_to_flowi(&fl6)); 577 578 sk = icmpv6_xmit_lock(net); 579 if (sk == NULL) 580 return; 581 np = inet6_sk(sk); 582 583 if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr)) 584 fl6.flowi6_oif = np->mcast_oif; 585 else if (!fl6.flowi6_oif) 586 fl6.flowi6_oif = np->ucast_oif; 587 588 err = ip6_dst_lookup(sk, &dst, &fl6); 589 if (err) 590 goto out; 591 dst = xfrm_lookup(net, dst, flowi6_to_flowi(&fl6), sk, 0); 592 if (IS_ERR(dst)) 593 goto out; 594 595 if (ipv6_addr_is_multicast(&fl6.daddr)) 596 hlimit = np->mcast_hops; 597 else 598 hlimit = np->hop_limit; 599 if (hlimit < 0) 600 hlimit = ip6_dst_hoplimit(dst); 601 602 idev = __in6_dev_get(skb->dev); 603 604 msg.skb = skb; 605 msg.offset = 0; 606 msg.type = ICMPV6_ECHO_REPLY; 607 608 tclass = ipv6_get_dsfield(ipv6_hdr(skb)); 609 err = ip6_append_data(sk, icmpv6_getfrag, &msg, skb->len + sizeof(struct icmp6hdr), 610 sizeof(struct icmp6hdr), hlimit, tclass, NULL, &fl6, 611 (struct rt6_info *)dst, MSG_DONTWAIT, 612 np->dontfrag); 613 614 if (err) { 615 ICMP6_INC_STATS_BH(net, idev, ICMP6_MIB_OUTERRORS); 616 ip6_flush_pending_frames(sk); 617 } else { 618 err = icmpv6_push_pending_frames(sk, &fl6, &tmp_hdr, 619 skb->len + sizeof(struct icmp6hdr)); 620 } 621 dst_release(dst); 622 out: 623 icmpv6_xmit_unlock(sk); 624 } 625 626 void icmpv6_notify(struct sk_buff *skb, u8 type, u8 code, __be32 info) 627 { 628 const struct inet6_protocol *ipprot; 629 int inner_offset; 630 __be16 frag_off; 631 u8 nexthdr; 632 633 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr))) 634 return; 635 636 nexthdr = ((struct ipv6hdr *)skb->data)->nexthdr; 637 if (ipv6_ext_hdr(nexthdr)) { 638 /* now skip over extension headers */ 639 inner_offset = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), 640 &nexthdr, &frag_off); 641 if (inner_offset<0) 642 return; 643 } else { 644 inner_offset = sizeof(struct ipv6hdr); 645 } 646 647 /* Checkin header including 8 bytes of inner protocol header. */ 648 if (!pskb_may_pull(skb, inner_offset+8)) 649 return; 650 651 /* BUGGG_FUTURE: we should try to parse exthdrs in this packet. 652 Without this we will not able f.e. to make source routed 653 pmtu discovery. 654 Corresponding argument (opt) to notifiers is already added. 655 --ANK (980726) 656 */ 657 658 rcu_read_lock(); 659 ipprot = rcu_dereference(inet6_protos[nexthdr]); 660 if (ipprot && ipprot->err_handler) 661 ipprot->err_handler(skb, NULL, type, code, inner_offset, info); 662 rcu_read_unlock(); 663 664 raw6_icmp_error(skb, nexthdr, type, code, inner_offset, info); 665 } 666 667 /* 668 * Handle icmp messages 669 */ 670 671 static int icmpv6_rcv(struct sk_buff *skb) 672 { 673 struct net_device *dev = skb->dev; 674 struct inet6_dev *idev = __in6_dev_get(dev); 675 const struct in6_addr *saddr, *daddr; 676 struct icmp6hdr *hdr; 677 u8 type; 678 679 if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) { 680 struct sec_path *sp = skb_sec_path(skb); 681 int nh; 682 683 if (!(sp && sp->xvec[sp->len - 1]->props.flags & 684 XFRM_STATE_ICMP)) 685 goto drop_no_count; 686 687 if (!pskb_may_pull(skb, sizeof(*hdr) + sizeof(struct ipv6hdr))) 688 goto drop_no_count; 689 690 nh = skb_network_offset(skb); 691 skb_set_network_header(skb, sizeof(*hdr)); 692 693 if (!xfrm6_policy_check_reverse(NULL, XFRM_POLICY_IN, skb)) 694 goto drop_no_count; 695 696 skb_set_network_header(skb, nh); 697 } 698 699 ICMP6_INC_STATS_BH(dev_net(dev), idev, ICMP6_MIB_INMSGS); 700 701 saddr = &ipv6_hdr(skb)->saddr; 702 daddr = &ipv6_hdr(skb)->daddr; 703 704 /* Perform checksum. */ 705 switch (skb->ip_summed) { 706 case CHECKSUM_COMPLETE: 707 if (!csum_ipv6_magic(saddr, daddr, skb->len, IPPROTO_ICMPV6, 708 skb->csum)) 709 break; 710 /* fall through */ 711 case CHECKSUM_NONE: 712 skb->csum = ~csum_unfold(csum_ipv6_magic(saddr, daddr, skb->len, 713 IPPROTO_ICMPV6, 0)); 714 if (__skb_checksum_complete(skb)) { 715 LIMIT_NETDEBUG(KERN_DEBUG 716 "ICMPv6 checksum failed [%pI6c > %pI6c]\n", 717 saddr, daddr); 718 goto csum_error; 719 } 720 } 721 722 if (!pskb_pull(skb, sizeof(*hdr))) 723 goto discard_it; 724 725 hdr = icmp6_hdr(skb); 726 727 type = hdr->icmp6_type; 728 729 ICMP6MSGIN_INC_STATS_BH(dev_net(dev), idev, type); 730 731 switch (type) { 732 case ICMPV6_ECHO_REQUEST: 733 icmpv6_echo_reply(skb); 734 break; 735 736 case ICMPV6_ECHO_REPLY: 737 ping_rcv(skb); 738 break; 739 740 case ICMPV6_PKT_TOOBIG: 741 /* BUGGG_FUTURE: if packet contains rthdr, we cannot update 742 standard destination cache. Seems, only "advanced" 743 destination cache will allow to solve this problem 744 --ANK (980726) 745 */ 746 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr))) 747 goto discard_it; 748 hdr = icmp6_hdr(skb); 749 750 /* 751 * Drop through to notify 752 */ 753 754 case ICMPV6_DEST_UNREACH: 755 case ICMPV6_TIME_EXCEED: 756 case ICMPV6_PARAMPROB: 757 icmpv6_notify(skb, type, hdr->icmp6_code, hdr->icmp6_mtu); 758 break; 759 760 case NDISC_ROUTER_SOLICITATION: 761 case NDISC_ROUTER_ADVERTISEMENT: 762 case NDISC_NEIGHBOUR_SOLICITATION: 763 case NDISC_NEIGHBOUR_ADVERTISEMENT: 764 case NDISC_REDIRECT: 765 ndisc_rcv(skb); 766 break; 767 768 case ICMPV6_MGM_QUERY: 769 igmp6_event_query(skb); 770 break; 771 772 case ICMPV6_MGM_REPORT: 773 igmp6_event_report(skb); 774 break; 775 776 case ICMPV6_MGM_REDUCTION: 777 case ICMPV6_NI_QUERY: 778 case ICMPV6_NI_REPLY: 779 case ICMPV6_MLD2_REPORT: 780 case ICMPV6_DHAAD_REQUEST: 781 case ICMPV6_DHAAD_REPLY: 782 case ICMPV6_MOBILE_PREFIX_SOL: 783 case ICMPV6_MOBILE_PREFIX_ADV: 784 break; 785 786 default: 787 LIMIT_NETDEBUG(KERN_DEBUG "icmpv6: msg of unknown type\n"); 788 789 /* informational */ 790 if (type & ICMPV6_INFOMSG_MASK) 791 break; 792 793 /* 794 * error of unknown type. 795 * must pass to upper level 796 */ 797 798 icmpv6_notify(skb, type, hdr->icmp6_code, hdr->icmp6_mtu); 799 } 800 801 kfree_skb(skb); 802 return 0; 803 804 csum_error: 805 ICMP6_INC_STATS_BH(dev_net(dev), idev, ICMP6_MIB_CSUMERRORS); 806 discard_it: 807 ICMP6_INC_STATS_BH(dev_net(dev), idev, ICMP6_MIB_INERRORS); 808 drop_no_count: 809 kfree_skb(skb); 810 return 0; 811 } 812 813 void icmpv6_flow_init(struct sock *sk, struct flowi6 *fl6, 814 u8 type, 815 const struct in6_addr *saddr, 816 const struct in6_addr *daddr, 817 int oif) 818 { 819 memset(fl6, 0, sizeof(*fl6)); 820 fl6->saddr = *saddr; 821 fl6->daddr = *daddr; 822 fl6->flowi6_proto = IPPROTO_ICMPV6; 823 fl6->fl6_icmp_type = type; 824 fl6->fl6_icmp_code = 0; 825 fl6->flowi6_oif = oif; 826 security_sk_classify_flow(sk, flowi6_to_flowi(fl6)); 827 } 828 829 /* 830 * Special lock-class for __icmpv6_sk: 831 */ 832 static struct lock_class_key icmpv6_socket_sk_dst_lock_key; 833 834 static int __net_init icmpv6_sk_init(struct net *net) 835 { 836 struct sock *sk; 837 int err, i, j; 838 839 net->ipv6.icmp_sk = 840 kzalloc(nr_cpu_ids * sizeof(struct sock *), GFP_KERNEL); 841 if (net->ipv6.icmp_sk == NULL) 842 return -ENOMEM; 843 844 for_each_possible_cpu(i) { 845 err = inet_ctl_sock_create(&sk, PF_INET6, 846 SOCK_RAW, IPPROTO_ICMPV6, net); 847 if (err < 0) { 848 pr_err("Failed to initialize the ICMP6 control socket (err %d)\n", 849 err); 850 goto fail; 851 } 852 853 net->ipv6.icmp_sk[i] = sk; 854 855 /* 856 * Split off their lock-class, because sk->sk_dst_lock 857 * gets used from softirqs, which is safe for 858 * __icmpv6_sk (because those never get directly used 859 * via userspace syscalls), but unsafe for normal sockets. 860 */ 861 lockdep_set_class(&sk->sk_dst_lock, 862 &icmpv6_socket_sk_dst_lock_key); 863 864 /* Enough space for 2 64K ICMP packets, including 865 * sk_buff struct overhead. 866 */ 867 sk->sk_sndbuf = 2 * SKB_TRUESIZE(64 * 1024); 868 } 869 return 0; 870 871 fail: 872 for (j = 0; j < i; j++) 873 inet_ctl_sock_destroy(net->ipv6.icmp_sk[j]); 874 kfree(net->ipv6.icmp_sk); 875 return err; 876 } 877 878 static void __net_exit icmpv6_sk_exit(struct net *net) 879 { 880 int i; 881 882 for_each_possible_cpu(i) { 883 inet_ctl_sock_destroy(net->ipv6.icmp_sk[i]); 884 } 885 kfree(net->ipv6.icmp_sk); 886 } 887 888 static struct pernet_operations icmpv6_sk_ops = { 889 .init = icmpv6_sk_init, 890 .exit = icmpv6_sk_exit, 891 }; 892 893 int __init icmpv6_init(void) 894 { 895 int err; 896 897 err = register_pernet_subsys(&icmpv6_sk_ops); 898 if (err < 0) 899 return err; 900 901 err = -EAGAIN; 902 if (inet6_add_protocol(&icmpv6_protocol, IPPROTO_ICMPV6) < 0) 903 goto fail; 904 905 err = inet6_register_icmp_sender(icmp6_send); 906 if (err) 907 goto sender_reg_err; 908 return 0; 909 910 sender_reg_err: 911 inet6_del_protocol(&icmpv6_protocol, IPPROTO_ICMPV6); 912 fail: 913 pr_err("Failed to register ICMP6 protocol\n"); 914 unregister_pernet_subsys(&icmpv6_sk_ops); 915 return err; 916 } 917 918 void icmpv6_cleanup(void) 919 { 920 inet6_unregister_icmp_sender(icmp6_send); 921 unregister_pernet_subsys(&icmpv6_sk_ops); 922 inet6_del_protocol(&icmpv6_protocol, IPPROTO_ICMPV6); 923 } 924 925 926 static const struct icmp6_err { 927 int err; 928 int fatal; 929 } tab_unreach[] = { 930 { /* NOROUTE */ 931 .err = ENETUNREACH, 932 .fatal = 0, 933 }, 934 { /* ADM_PROHIBITED */ 935 .err = EACCES, 936 .fatal = 1, 937 }, 938 { /* Was NOT_NEIGHBOUR, now reserved */ 939 .err = EHOSTUNREACH, 940 .fatal = 0, 941 }, 942 { /* ADDR_UNREACH */ 943 .err = EHOSTUNREACH, 944 .fatal = 0, 945 }, 946 { /* PORT_UNREACH */ 947 .err = ECONNREFUSED, 948 .fatal = 1, 949 }, 950 { /* POLICY_FAIL */ 951 .err = EACCES, 952 .fatal = 1, 953 }, 954 { /* REJECT_ROUTE */ 955 .err = EACCES, 956 .fatal = 1, 957 }, 958 }; 959 960 int icmpv6_err_convert(u8 type, u8 code, int *err) 961 { 962 int fatal = 0; 963 964 *err = EPROTO; 965 966 switch (type) { 967 case ICMPV6_DEST_UNREACH: 968 fatal = 1; 969 if (code < ARRAY_SIZE(tab_unreach)) { 970 *err = tab_unreach[code].err; 971 fatal = tab_unreach[code].fatal; 972 } 973 break; 974 975 case ICMPV6_PKT_TOOBIG: 976 *err = EMSGSIZE; 977 break; 978 979 case ICMPV6_PARAMPROB: 980 *err = EPROTO; 981 fatal = 1; 982 break; 983 984 case ICMPV6_TIME_EXCEED: 985 *err = EHOSTUNREACH; 986 break; 987 } 988 989 return fatal; 990 } 991 EXPORT_SYMBOL(icmpv6_err_convert); 992 993 #ifdef CONFIG_SYSCTL 994 static struct ctl_table ipv6_icmp_table_template[] = { 995 { 996 .procname = "ratelimit", 997 .data = &init_net.ipv6.sysctl.icmpv6_time, 998 .maxlen = sizeof(int), 999 .mode = 0644, 1000 .proc_handler = proc_dointvec_ms_jiffies, 1001 }, 1002 { }, 1003 }; 1004 1005 struct ctl_table * __net_init ipv6_icmp_sysctl_init(struct net *net) 1006 { 1007 struct ctl_table *table; 1008 1009 table = kmemdup(ipv6_icmp_table_template, 1010 sizeof(ipv6_icmp_table_template), 1011 GFP_KERNEL); 1012 1013 if (table) 1014 table[0].data = &net->ipv6.sysctl.icmpv6_time; 1015 1016 return table; 1017 } 1018 #endif 1019 1020