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 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 static void icmpv6_echo_reply(struct sk_buff *skb) 562 { 563 struct net *net = dev_net(skb->dev); 564 struct sock *sk; 565 struct inet6_dev *idev; 566 struct ipv6_pinfo *np; 567 const struct in6_addr *saddr = NULL; 568 struct icmp6hdr *icmph = icmp6_hdr(skb); 569 struct icmp6hdr tmp_hdr; 570 struct flowi6 fl6; 571 struct icmpv6_msg msg; 572 struct dst_entry *dst; 573 struct ipcm6_cookie ipc6; 574 int err = 0; 575 u32 mark = IP6_REPLY_MARK(net, skb->mark); 576 struct sockcm_cookie sockc_unused = {0}; 577 578 saddr = &ipv6_hdr(skb)->daddr; 579 580 if (!ipv6_unicast_destination(skb) && 581 !(net->ipv6.sysctl.anycast_src_echo_reply && 582 ipv6_anycast_destination(skb_dst(skb), saddr))) 583 saddr = NULL; 584 585 memcpy(&tmp_hdr, icmph, sizeof(tmp_hdr)); 586 tmp_hdr.icmp6_type = ICMPV6_ECHO_REPLY; 587 588 memset(&fl6, 0, sizeof(fl6)); 589 fl6.flowi6_proto = IPPROTO_ICMPV6; 590 fl6.daddr = ipv6_hdr(skb)->saddr; 591 if (saddr) 592 fl6.saddr = *saddr; 593 fl6.flowi6_oif = skb->dev->ifindex; 594 fl6.fl6_icmp_type = ICMPV6_ECHO_REPLY; 595 fl6.flowi6_mark = mark; 596 security_skb_classify_flow(skb, flowi6_to_flowi(&fl6)); 597 598 sk = icmpv6_xmit_lock(net); 599 if (!sk) 600 return; 601 sk->sk_mark = mark; 602 np = inet6_sk(sk); 603 604 if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr)) 605 fl6.flowi6_oif = np->mcast_oif; 606 else if (!fl6.flowi6_oif) 607 fl6.flowi6_oif = np->ucast_oif; 608 609 err = ip6_dst_lookup(net, sk, &dst, &fl6); 610 if (err) 611 goto out; 612 dst = xfrm_lookup(net, dst, flowi6_to_flowi(&fl6), sk, 0); 613 if (IS_ERR(dst)) 614 goto out; 615 616 idev = __in6_dev_get(skb->dev); 617 618 msg.skb = skb; 619 msg.offset = 0; 620 msg.type = ICMPV6_ECHO_REPLY; 621 622 ipc6.hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst); 623 ipc6.tclass = ipv6_get_dsfield(ipv6_hdr(skb)); 624 ipc6.dontfrag = np->dontfrag; 625 ipc6.opt = NULL; 626 627 err = ip6_append_data(sk, icmpv6_getfrag, &msg, skb->len + sizeof(struct icmp6hdr), 628 sizeof(struct icmp6hdr), &ipc6, &fl6, 629 (struct rt6_info *)dst, MSG_DONTWAIT, 630 &sockc_unused); 631 632 if (err) { 633 __ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTERRORS); 634 ip6_flush_pending_frames(sk); 635 } else { 636 err = icmpv6_push_pending_frames(sk, &fl6, &tmp_hdr, 637 skb->len + sizeof(struct icmp6hdr)); 638 } 639 dst_release(dst); 640 out: 641 icmpv6_xmit_unlock(sk); 642 } 643 644 void icmpv6_notify(struct sk_buff *skb, u8 type, u8 code, __be32 info) 645 { 646 const struct inet6_protocol *ipprot; 647 int inner_offset; 648 __be16 frag_off; 649 u8 nexthdr; 650 struct net *net = dev_net(skb->dev); 651 652 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr))) 653 goto out; 654 655 nexthdr = ((struct ipv6hdr *)skb->data)->nexthdr; 656 if (ipv6_ext_hdr(nexthdr)) { 657 /* now skip over extension headers */ 658 inner_offset = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), 659 &nexthdr, &frag_off); 660 if (inner_offset < 0) 661 goto out; 662 } else { 663 inner_offset = sizeof(struct ipv6hdr); 664 } 665 666 /* Checkin header including 8 bytes of inner protocol header. */ 667 if (!pskb_may_pull(skb, inner_offset+8)) 668 goto out; 669 670 /* BUGGG_FUTURE: we should try to parse exthdrs in this packet. 671 Without this we will not able f.e. to make source routed 672 pmtu discovery. 673 Corresponding argument (opt) to notifiers is already added. 674 --ANK (980726) 675 */ 676 677 ipprot = rcu_dereference(inet6_protos[nexthdr]); 678 if (ipprot && ipprot->err_handler) 679 ipprot->err_handler(skb, NULL, type, code, inner_offset, info); 680 681 raw6_icmp_error(skb, nexthdr, type, code, inner_offset, info); 682 return; 683 684 out: 685 __ICMP6_INC_STATS(net, __in6_dev_get(skb->dev), ICMP6_MIB_INERRORS); 686 } 687 688 /* 689 * Handle icmp messages 690 */ 691 692 static int icmpv6_rcv(struct sk_buff *skb) 693 { 694 struct net_device *dev = skb->dev; 695 struct inet6_dev *idev = __in6_dev_get(dev); 696 const struct in6_addr *saddr, *daddr; 697 struct icmp6hdr *hdr; 698 u8 type; 699 bool success = false; 700 701 if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) { 702 struct sec_path *sp = skb_sec_path(skb); 703 int nh; 704 705 if (!(sp && sp->xvec[sp->len - 1]->props.flags & 706 XFRM_STATE_ICMP)) 707 goto drop_no_count; 708 709 if (!pskb_may_pull(skb, sizeof(*hdr) + sizeof(struct ipv6hdr))) 710 goto drop_no_count; 711 712 nh = skb_network_offset(skb); 713 skb_set_network_header(skb, sizeof(*hdr)); 714 715 if (!xfrm6_policy_check_reverse(NULL, XFRM_POLICY_IN, skb)) 716 goto drop_no_count; 717 718 skb_set_network_header(skb, nh); 719 } 720 721 __ICMP6_INC_STATS(dev_net(dev), idev, ICMP6_MIB_INMSGS); 722 723 saddr = &ipv6_hdr(skb)->saddr; 724 daddr = &ipv6_hdr(skb)->daddr; 725 726 if (skb_checksum_validate(skb, IPPROTO_ICMPV6, ip6_compute_pseudo)) { 727 net_dbg_ratelimited("ICMPv6 checksum failed [%pI6c > %pI6c]\n", 728 saddr, daddr); 729 goto csum_error; 730 } 731 732 if (!pskb_pull(skb, sizeof(*hdr))) 733 goto discard_it; 734 735 hdr = icmp6_hdr(skb); 736 737 type = hdr->icmp6_type; 738 739 ICMP6MSGIN_INC_STATS(dev_net(dev), idev, type); 740 741 switch (type) { 742 case ICMPV6_ECHO_REQUEST: 743 icmpv6_echo_reply(skb); 744 break; 745 746 case ICMPV6_ECHO_REPLY: 747 success = ping_rcv(skb); 748 break; 749 750 case ICMPV6_PKT_TOOBIG: 751 /* BUGGG_FUTURE: if packet contains rthdr, we cannot update 752 standard destination cache. Seems, only "advanced" 753 destination cache will allow to solve this problem 754 --ANK (980726) 755 */ 756 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr))) 757 goto discard_it; 758 hdr = icmp6_hdr(skb); 759 760 /* 761 * Drop through to notify 762 */ 763 764 case ICMPV6_DEST_UNREACH: 765 case ICMPV6_TIME_EXCEED: 766 case ICMPV6_PARAMPROB: 767 icmpv6_notify(skb, type, hdr->icmp6_code, hdr->icmp6_mtu); 768 break; 769 770 case NDISC_ROUTER_SOLICITATION: 771 case NDISC_ROUTER_ADVERTISEMENT: 772 case NDISC_NEIGHBOUR_SOLICITATION: 773 case NDISC_NEIGHBOUR_ADVERTISEMENT: 774 case NDISC_REDIRECT: 775 ndisc_rcv(skb); 776 break; 777 778 case ICMPV6_MGM_QUERY: 779 igmp6_event_query(skb); 780 break; 781 782 case ICMPV6_MGM_REPORT: 783 igmp6_event_report(skb); 784 break; 785 786 case ICMPV6_MGM_REDUCTION: 787 case ICMPV6_NI_QUERY: 788 case ICMPV6_NI_REPLY: 789 case ICMPV6_MLD2_REPORT: 790 case ICMPV6_DHAAD_REQUEST: 791 case ICMPV6_DHAAD_REPLY: 792 case ICMPV6_MOBILE_PREFIX_SOL: 793 case ICMPV6_MOBILE_PREFIX_ADV: 794 break; 795 796 default: 797 /* informational */ 798 if (type & ICMPV6_INFOMSG_MASK) 799 break; 800 801 net_dbg_ratelimited("icmpv6: msg of unknown type [%pI6c > %pI6c]\n", 802 saddr, daddr); 803 804 /* 805 * error of unknown type. 806 * must pass to upper level 807 */ 808 809 icmpv6_notify(skb, type, hdr->icmp6_code, hdr->icmp6_mtu); 810 } 811 812 /* until the v6 path can be better sorted assume failure and 813 * preserve the status quo behaviour for the rest of the paths to here 814 */ 815 if (success) 816 consume_skb(skb); 817 else 818 kfree_skb(skb); 819 820 return 0; 821 822 csum_error: 823 __ICMP6_INC_STATS(dev_net(dev), idev, ICMP6_MIB_CSUMERRORS); 824 discard_it: 825 __ICMP6_INC_STATS(dev_net(dev), idev, ICMP6_MIB_INERRORS); 826 drop_no_count: 827 kfree_skb(skb); 828 return 0; 829 } 830 831 void icmpv6_flow_init(struct sock *sk, struct flowi6 *fl6, 832 u8 type, 833 const struct in6_addr *saddr, 834 const struct in6_addr *daddr, 835 int oif) 836 { 837 memset(fl6, 0, sizeof(*fl6)); 838 fl6->saddr = *saddr; 839 fl6->daddr = *daddr; 840 fl6->flowi6_proto = IPPROTO_ICMPV6; 841 fl6->fl6_icmp_type = type; 842 fl6->fl6_icmp_code = 0; 843 fl6->flowi6_oif = oif; 844 security_sk_classify_flow(sk, flowi6_to_flowi(fl6)); 845 } 846 847 static int __net_init icmpv6_sk_init(struct net *net) 848 { 849 struct sock *sk; 850 int err, i, j; 851 852 net->ipv6.icmp_sk = 853 kzalloc(nr_cpu_ids * sizeof(struct sock *), GFP_KERNEL); 854 if (!net->ipv6.icmp_sk) 855 return -ENOMEM; 856 857 for_each_possible_cpu(i) { 858 err = inet_ctl_sock_create(&sk, PF_INET6, 859 SOCK_RAW, IPPROTO_ICMPV6, net); 860 if (err < 0) { 861 pr_err("Failed to initialize the ICMP6 control socket (err %d)\n", 862 err); 863 goto fail; 864 } 865 866 net->ipv6.icmp_sk[i] = sk; 867 868 /* Enough space for 2 64K ICMP packets, including 869 * sk_buff struct overhead. 870 */ 871 sk->sk_sndbuf = 2 * SKB_TRUESIZE(64 * 1024); 872 } 873 return 0; 874 875 fail: 876 for (j = 0; j < i; j++) 877 inet_ctl_sock_destroy(net->ipv6.icmp_sk[j]); 878 kfree(net->ipv6.icmp_sk); 879 return err; 880 } 881 882 static void __net_exit icmpv6_sk_exit(struct net *net) 883 { 884 int i; 885 886 for_each_possible_cpu(i) { 887 inet_ctl_sock_destroy(net->ipv6.icmp_sk[i]); 888 } 889 kfree(net->ipv6.icmp_sk); 890 } 891 892 static struct pernet_operations icmpv6_sk_ops = { 893 .init = icmpv6_sk_init, 894 .exit = icmpv6_sk_exit, 895 }; 896 897 int __init icmpv6_init(void) 898 { 899 int err; 900 901 err = register_pernet_subsys(&icmpv6_sk_ops); 902 if (err < 0) 903 return err; 904 905 err = -EAGAIN; 906 if (inet6_add_protocol(&icmpv6_protocol, IPPROTO_ICMPV6) < 0) 907 goto fail; 908 909 err = inet6_register_icmp_sender(icmp6_send); 910 if (err) 911 goto sender_reg_err; 912 return 0; 913 914 sender_reg_err: 915 inet6_del_protocol(&icmpv6_protocol, IPPROTO_ICMPV6); 916 fail: 917 pr_err("Failed to register ICMP6 protocol\n"); 918 unregister_pernet_subsys(&icmpv6_sk_ops); 919 return err; 920 } 921 922 void icmpv6_cleanup(void) 923 { 924 inet6_unregister_icmp_sender(icmp6_send); 925 unregister_pernet_subsys(&icmpv6_sk_ops); 926 inet6_del_protocol(&icmpv6_protocol, IPPROTO_ICMPV6); 927 } 928 929 930 static const struct icmp6_err { 931 int err; 932 int fatal; 933 } tab_unreach[] = { 934 { /* NOROUTE */ 935 .err = ENETUNREACH, 936 .fatal = 0, 937 }, 938 { /* ADM_PROHIBITED */ 939 .err = EACCES, 940 .fatal = 1, 941 }, 942 { /* Was NOT_NEIGHBOUR, now reserved */ 943 .err = EHOSTUNREACH, 944 .fatal = 0, 945 }, 946 { /* ADDR_UNREACH */ 947 .err = EHOSTUNREACH, 948 .fatal = 0, 949 }, 950 { /* PORT_UNREACH */ 951 .err = ECONNREFUSED, 952 .fatal = 1, 953 }, 954 { /* POLICY_FAIL */ 955 .err = EACCES, 956 .fatal = 1, 957 }, 958 { /* REJECT_ROUTE */ 959 .err = EACCES, 960 .fatal = 1, 961 }, 962 }; 963 964 int icmpv6_err_convert(u8 type, u8 code, int *err) 965 { 966 int fatal = 0; 967 968 *err = EPROTO; 969 970 switch (type) { 971 case ICMPV6_DEST_UNREACH: 972 fatal = 1; 973 if (code < ARRAY_SIZE(tab_unreach)) { 974 *err = tab_unreach[code].err; 975 fatal = tab_unreach[code].fatal; 976 } 977 break; 978 979 case ICMPV6_PKT_TOOBIG: 980 *err = EMSGSIZE; 981 break; 982 983 case ICMPV6_PARAMPROB: 984 *err = EPROTO; 985 fatal = 1; 986 break; 987 988 case ICMPV6_TIME_EXCEED: 989 *err = EHOSTUNREACH; 990 break; 991 } 992 993 return fatal; 994 } 995 EXPORT_SYMBOL(icmpv6_err_convert); 996 997 #ifdef CONFIG_SYSCTL 998 static struct ctl_table ipv6_icmp_table_template[] = { 999 { 1000 .procname = "ratelimit", 1001 .data = &init_net.ipv6.sysctl.icmpv6_time, 1002 .maxlen = sizeof(int), 1003 .mode = 0644, 1004 .proc_handler = proc_dointvec_ms_jiffies, 1005 }, 1006 { }, 1007 }; 1008 1009 struct ctl_table * __net_init ipv6_icmp_sysctl_init(struct net *net) 1010 { 1011 struct ctl_table *table; 1012 1013 table = kmemdup(ipv6_icmp_table_template, 1014 sizeof(ipv6_icmp_table_template), 1015 GFP_KERNEL); 1016 1017 if (table) 1018 table[0].data = &net->ipv6.sysctl.icmpv6_time; 1019 1020 return table; 1021 } 1022 #endif 1023