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 ipv6_chk_acast_addr_src(net, skb->dev, &hdr->daddr)) 418 saddr = &hdr->daddr; 419 420 /* 421 * Dest addr check 422 */ 423 424 if ((addr_type & IPV6_ADDR_MULTICAST || skb->pkt_type != PACKET_HOST)) { 425 if (type != ICMPV6_PKT_TOOBIG && 426 !(type == ICMPV6_PARAMPROB && 427 code == ICMPV6_UNK_OPTION && 428 (opt_unrec(skb, info)))) 429 return; 430 431 saddr = NULL; 432 } 433 434 addr_type = ipv6_addr_type(&hdr->saddr); 435 436 /* 437 * Source addr check 438 */ 439 440 if (__ipv6_addr_needs_scope_id(addr_type)) 441 iif = skb->dev->ifindex; 442 443 /* 444 * Must not send error if the source does not uniquely 445 * identify a single node (RFC2463 Section 2.4). 446 * We check unspecified / multicast addresses here, 447 * and anycast addresses will be checked later. 448 */ 449 if ((addr_type == IPV6_ADDR_ANY) || (addr_type & IPV6_ADDR_MULTICAST)) { 450 LIMIT_NETDEBUG(KERN_DEBUG "icmp6_send: addr_any/mcast source\n"); 451 return; 452 } 453 454 /* 455 * Never answer to a ICMP packet. 456 */ 457 if (is_ineligible(skb)) { 458 LIMIT_NETDEBUG(KERN_DEBUG "icmp6_send: no reply to icmp error\n"); 459 return; 460 } 461 462 mip6_addr_swap(skb); 463 464 memset(&fl6, 0, sizeof(fl6)); 465 fl6.flowi6_proto = IPPROTO_ICMPV6; 466 fl6.daddr = hdr->saddr; 467 if (saddr) 468 fl6.saddr = *saddr; 469 fl6.flowi6_oif = iif; 470 fl6.fl6_icmp_type = type; 471 fl6.fl6_icmp_code = code; 472 security_skb_classify_flow(skb, flowi6_to_flowi(&fl6)); 473 474 sk = icmpv6_xmit_lock(net); 475 if (sk == NULL) 476 return; 477 np = inet6_sk(sk); 478 479 if (!icmpv6_xrlim_allow(sk, type, &fl6)) 480 goto out; 481 482 tmp_hdr.icmp6_type = type; 483 tmp_hdr.icmp6_code = code; 484 tmp_hdr.icmp6_cksum = 0; 485 tmp_hdr.icmp6_pointer = htonl(info); 486 487 if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr)) 488 fl6.flowi6_oif = np->mcast_oif; 489 else if (!fl6.flowi6_oif) 490 fl6.flowi6_oif = np->ucast_oif; 491 492 dst = icmpv6_route_lookup(net, skb, sk, &fl6); 493 if (IS_ERR(dst)) 494 goto out; 495 496 if (ipv6_addr_is_multicast(&fl6.daddr)) 497 hlimit = np->mcast_hops; 498 else 499 hlimit = np->hop_limit; 500 if (hlimit < 0) 501 hlimit = ip6_dst_hoplimit(dst); 502 503 msg.skb = skb; 504 msg.offset = skb_network_offset(skb); 505 msg.type = type; 506 507 len = skb->len - msg.offset; 508 len = min_t(unsigned int, len, IPV6_MIN_MTU - sizeof(struct ipv6hdr) -sizeof(struct icmp6hdr)); 509 if (len < 0) { 510 LIMIT_NETDEBUG(KERN_DEBUG "icmp: len problem\n"); 511 goto out_dst_release; 512 } 513 514 rcu_read_lock(); 515 idev = __in6_dev_get(skb->dev); 516 517 err = ip6_append_data(sk, icmpv6_getfrag, &msg, 518 len + sizeof(struct icmp6hdr), 519 sizeof(struct icmp6hdr), hlimit, 520 np->tclass, NULL, &fl6, (struct rt6_info *)dst, 521 MSG_DONTWAIT, np->dontfrag); 522 if (err) { 523 ICMP6_INC_STATS_BH(net, idev, ICMP6_MIB_OUTERRORS); 524 ip6_flush_pending_frames(sk); 525 } else { 526 err = icmpv6_push_pending_frames(sk, &fl6, &tmp_hdr, 527 len + sizeof(struct icmp6hdr)); 528 } 529 rcu_read_unlock(); 530 out_dst_release: 531 dst_release(dst); 532 out: 533 icmpv6_xmit_unlock(sk); 534 } 535 536 /* Slightly more convenient version of icmp6_send. 537 */ 538 void icmpv6_param_prob(struct sk_buff *skb, u8 code, int pos) 539 { 540 icmp6_send(skb, ICMPV6_PARAMPROB, code, pos); 541 kfree_skb(skb); 542 } 543 544 static void icmpv6_echo_reply(struct sk_buff *skb) 545 { 546 struct net *net = dev_net(skb->dev); 547 struct sock *sk; 548 struct inet6_dev *idev; 549 struct ipv6_pinfo *np; 550 const struct in6_addr *saddr = NULL; 551 struct icmp6hdr *icmph = icmp6_hdr(skb); 552 struct icmp6hdr tmp_hdr; 553 struct flowi6 fl6; 554 struct icmpv6_msg msg; 555 struct dst_entry *dst; 556 int err = 0; 557 int hlimit; 558 u8 tclass; 559 560 saddr = &ipv6_hdr(skb)->daddr; 561 562 if (!ipv6_unicast_destination(skb) && 563 !(net->ipv6.sysctl.anycast_src_echo_reply && 564 ipv6_anycast_destination(skb))) 565 saddr = NULL; 566 567 memcpy(&tmp_hdr, icmph, sizeof(tmp_hdr)); 568 tmp_hdr.icmp6_type = ICMPV6_ECHO_REPLY; 569 570 memset(&fl6, 0, sizeof(fl6)); 571 fl6.flowi6_proto = IPPROTO_ICMPV6; 572 fl6.daddr = ipv6_hdr(skb)->saddr; 573 if (saddr) 574 fl6.saddr = *saddr; 575 fl6.flowi6_oif = skb->dev->ifindex; 576 fl6.fl6_icmp_type = ICMPV6_ECHO_REPLY; 577 security_skb_classify_flow(skb, flowi6_to_flowi(&fl6)); 578 579 sk = icmpv6_xmit_lock(net); 580 if (sk == NULL) 581 return; 582 np = inet6_sk(sk); 583 584 if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr)) 585 fl6.flowi6_oif = np->mcast_oif; 586 else if (!fl6.flowi6_oif) 587 fl6.flowi6_oif = np->ucast_oif; 588 589 err = ip6_dst_lookup(sk, &dst, &fl6); 590 if (err) 591 goto out; 592 dst = xfrm_lookup(net, dst, flowi6_to_flowi(&fl6), sk, 0); 593 if (IS_ERR(dst)) 594 goto out; 595 596 if (ipv6_addr_is_multicast(&fl6.daddr)) 597 hlimit = np->mcast_hops; 598 else 599 hlimit = np->hop_limit; 600 if (hlimit < 0) 601 hlimit = ip6_dst_hoplimit(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; 633 634 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr))) 635 return; 636 637 nexthdr = ((struct ipv6hdr *)skb->data)->nexthdr; 638 if (ipv6_ext_hdr(nexthdr)) { 639 /* now skip over extension headers */ 640 inner_offset = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), 641 &nexthdr, &frag_off); 642 if (inner_offset<0) 643 return; 644 } else { 645 inner_offset = sizeof(struct ipv6hdr); 646 } 647 648 /* Checkin header including 8 bytes of inner protocol header. */ 649 if (!pskb_may_pull(skb, inner_offset+8)) 650 return; 651 652 /* BUGGG_FUTURE: we should try to parse exthdrs in this packet. 653 Without this we will not able f.e. to make source routed 654 pmtu discovery. 655 Corresponding argument (opt) to notifiers is already added. 656 --ANK (980726) 657 */ 658 659 rcu_read_lock(); 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 rcu_read_unlock(); 664 665 raw6_icmp_error(skb, nexthdr, type, code, inner_offset, info); 666 } 667 668 /* 669 * Handle icmp messages 670 */ 671 672 static int icmpv6_rcv(struct sk_buff *skb) 673 { 674 struct net_device *dev = skb->dev; 675 struct inet6_dev *idev = __in6_dev_get(dev); 676 const struct in6_addr *saddr, *daddr; 677 struct icmp6hdr *hdr; 678 u8 type; 679 680 if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) { 681 struct sec_path *sp = skb_sec_path(skb); 682 int nh; 683 684 if (!(sp && sp->xvec[sp->len - 1]->props.flags & 685 XFRM_STATE_ICMP)) 686 goto drop_no_count; 687 688 if (!pskb_may_pull(skb, sizeof(*hdr) + sizeof(struct ipv6hdr))) 689 goto drop_no_count; 690 691 nh = skb_network_offset(skb); 692 skb_set_network_header(skb, sizeof(*hdr)); 693 694 if (!xfrm6_policy_check_reverse(NULL, XFRM_POLICY_IN, skb)) 695 goto drop_no_count; 696 697 skb_set_network_header(skb, nh); 698 } 699 700 ICMP6_INC_STATS_BH(dev_net(dev), idev, ICMP6_MIB_INMSGS); 701 702 saddr = &ipv6_hdr(skb)->saddr; 703 daddr = &ipv6_hdr(skb)->daddr; 704 705 /* Perform checksum. */ 706 switch (skb->ip_summed) { 707 case CHECKSUM_COMPLETE: 708 if (!csum_ipv6_magic(saddr, daddr, skb->len, IPPROTO_ICMPV6, 709 skb->csum)) 710 break; 711 /* fall through */ 712 case CHECKSUM_NONE: 713 skb->csum = ~csum_unfold(csum_ipv6_magic(saddr, daddr, skb->len, 714 IPPROTO_ICMPV6, 0)); 715 if (__skb_checksum_complete(skb)) { 716 LIMIT_NETDEBUG(KERN_DEBUG 717 "ICMPv6 checksum failed [%pI6c > %pI6c]\n", 718 saddr, daddr); 719 goto csum_error; 720 } 721 } 722 723 if (!pskb_pull(skb, sizeof(*hdr))) 724 goto discard_it; 725 726 hdr = icmp6_hdr(skb); 727 728 type = hdr->icmp6_type; 729 730 ICMP6MSGIN_INC_STATS_BH(dev_net(dev), idev, type); 731 732 switch (type) { 733 case ICMPV6_ECHO_REQUEST: 734 icmpv6_echo_reply(skb); 735 break; 736 737 case ICMPV6_ECHO_REPLY: 738 ping_rcv(skb); 739 break; 740 741 case ICMPV6_PKT_TOOBIG: 742 /* BUGGG_FUTURE: if packet contains rthdr, we cannot update 743 standard destination cache. Seems, only "advanced" 744 destination cache will allow to solve this problem 745 --ANK (980726) 746 */ 747 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr))) 748 goto discard_it; 749 hdr = icmp6_hdr(skb); 750 751 /* 752 * Drop through to notify 753 */ 754 755 case ICMPV6_DEST_UNREACH: 756 case ICMPV6_TIME_EXCEED: 757 case ICMPV6_PARAMPROB: 758 icmpv6_notify(skb, type, hdr->icmp6_code, hdr->icmp6_mtu); 759 break; 760 761 case NDISC_ROUTER_SOLICITATION: 762 case NDISC_ROUTER_ADVERTISEMENT: 763 case NDISC_NEIGHBOUR_SOLICITATION: 764 case NDISC_NEIGHBOUR_ADVERTISEMENT: 765 case NDISC_REDIRECT: 766 ndisc_rcv(skb); 767 break; 768 769 case ICMPV6_MGM_QUERY: 770 igmp6_event_query(skb); 771 break; 772 773 case ICMPV6_MGM_REPORT: 774 igmp6_event_report(skb); 775 break; 776 777 case ICMPV6_MGM_REDUCTION: 778 case ICMPV6_NI_QUERY: 779 case ICMPV6_NI_REPLY: 780 case ICMPV6_MLD2_REPORT: 781 case ICMPV6_DHAAD_REQUEST: 782 case ICMPV6_DHAAD_REPLY: 783 case ICMPV6_MOBILE_PREFIX_SOL: 784 case ICMPV6_MOBILE_PREFIX_ADV: 785 break; 786 787 default: 788 LIMIT_NETDEBUG(KERN_DEBUG "icmpv6: msg of unknown type\n"); 789 790 /* informational */ 791 if (type & ICMPV6_INFOMSG_MASK) 792 break; 793 794 /* 795 * error of unknown type. 796 * must pass to upper level 797 */ 798 799 icmpv6_notify(skb, type, hdr->icmp6_code, hdr->icmp6_mtu); 800 } 801 802 kfree_skb(skb); 803 return 0; 804 805 csum_error: 806 ICMP6_INC_STATS_BH(dev_net(dev), idev, ICMP6_MIB_CSUMERRORS); 807 discard_it: 808 ICMP6_INC_STATS_BH(dev_net(dev), idev, ICMP6_MIB_INERRORS); 809 drop_no_count: 810 kfree_skb(skb); 811 return 0; 812 } 813 814 void icmpv6_flow_init(struct sock *sk, struct flowi6 *fl6, 815 u8 type, 816 const struct in6_addr *saddr, 817 const struct in6_addr *daddr, 818 int oif) 819 { 820 memset(fl6, 0, sizeof(*fl6)); 821 fl6->saddr = *saddr; 822 fl6->daddr = *daddr; 823 fl6->flowi6_proto = IPPROTO_ICMPV6; 824 fl6->fl6_icmp_type = type; 825 fl6->fl6_icmp_code = 0; 826 fl6->flowi6_oif = oif; 827 security_sk_classify_flow(sk, flowi6_to_flowi(fl6)); 828 } 829 830 /* 831 * Special lock-class for __icmpv6_sk: 832 */ 833 static struct lock_class_key icmpv6_socket_sk_dst_lock_key; 834 835 static int __net_init icmpv6_sk_init(struct net *net) 836 { 837 struct sock *sk; 838 int err, i, j; 839 840 net->ipv6.icmp_sk = 841 kzalloc(nr_cpu_ids * sizeof(struct sock *), GFP_KERNEL); 842 if (net->ipv6.icmp_sk == NULL) 843 return -ENOMEM; 844 845 for_each_possible_cpu(i) { 846 err = inet_ctl_sock_create(&sk, PF_INET6, 847 SOCK_RAW, IPPROTO_ICMPV6, net); 848 if (err < 0) { 849 pr_err("Failed to initialize the ICMP6 control socket (err %d)\n", 850 err); 851 goto fail; 852 } 853 854 net->ipv6.icmp_sk[i] = sk; 855 856 /* 857 * Split off their lock-class, because sk->sk_dst_lock 858 * gets used from softirqs, which is safe for 859 * __icmpv6_sk (because those never get directly used 860 * via userspace syscalls), but unsafe for normal sockets. 861 */ 862 lockdep_set_class(&sk->sk_dst_lock, 863 &icmpv6_socket_sk_dst_lock_key); 864 865 /* Enough space for 2 64K ICMP packets, including 866 * sk_buff struct overhead. 867 */ 868 sk->sk_sndbuf = 2 * SKB_TRUESIZE(64 * 1024); 869 } 870 return 0; 871 872 fail: 873 for (j = 0; j < i; j++) 874 inet_ctl_sock_destroy(net->ipv6.icmp_sk[j]); 875 kfree(net->ipv6.icmp_sk); 876 return err; 877 } 878 879 static void __net_exit icmpv6_sk_exit(struct net *net) 880 { 881 int i; 882 883 for_each_possible_cpu(i) { 884 inet_ctl_sock_destroy(net->ipv6.icmp_sk[i]); 885 } 886 kfree(net->ipv6.icmp_sk); 887 } 888 889 static struct pernet_operations icmpv6_sk_ops = { 890 .init = icmpv6_sk_init, 891 .exit = icmpv6_sk_exit, 892 }; 893 894 int __init icmpv6_init(void) 895 { 896 int err; 897 898 err = register_pernet_subsys(&icmpv6_sk_ops); 899 if (err < 0) 900 return err; 901 902 err = -EAGAIN; 903 if (inet6_add_protocol(&icmpv6_protocol, IPPROTO_ICMPV6) < 0) 904 goto fail; 905 906 err = inet6_register_icmp_sender(icmp6_send); 907 if (err) 908 goto sender_reg_err; 909 return 0; 910 911 sender_reg_err: 912 inet6_del_protocol(&icmpv6_protocol, IPPROTO_ICMPV6); 913 fail: 914 pr_err("Failed to register ICMP6 protocol\n"); 915 unregister_pernet_subsys(&icmpv6_sk_ops); 916 return err; 917 } 918 919 void icmpv6_cleanup(void) 920 { 921 inet6_unregister_icmp_sender(icmp6_send); 922 unregister_pernet_subsys(&icmpv6_sk_ops); 923 inet6_del_protocol(&icmpv6_protocol, IPPROTO_ICMPV6); 924 } 925 926 927 static const struct icmp6_err { 928 int err; 929 int fatal; 930 } tab_unreach[] = { 931 { /* NOROUTE */ 932 .err = ENETUNREACH, 933 .fatal = 0, 934 }, 935 { /* ADM_PROHIBITED */ 936 .err = EACCES, 937 .fatal = 1, 938 }, 939 { /* Was NOT_NEIGHBOUR, now reserved */ 940 .err = EHOSTUNREACH, 941 .fatal = 0, 942 }, 943 { /* ADDR_UNREACH */ 944 .err = EHOSTUNREACH, 945 .fatal = 0, 946 }, 947 { /* PORT_UNREACH */ 948 .err = ECONNREFUSED, 949 .fatal = 1, 950 }, 951 { /* POLICY_FAIL */ 952 .err = EACCES, 953 .fatal = 1, 954 }, 955 { /* REJECT_ROUTE */ 956 .err = EACCES, 957 .fatal = 1, 958 }, 959 }; 960 961 int icmpv6_err_convert(u8 type, u8 code, int *err) 962 { 963 int fatal = 0; 964 965 *err = EPROTO; 966 967 switch (type) { 968 case ICMPV6_DEST_UNREACH: 969 fatal = 1; 970 if (code < ARRAY_SIZE(tab_unreach)) { 971 *err = tab_unreach[code].err; 972 fatal = tab_unreach[code].fatal; 973 } 974 break; 975 976 case ICMPV6_PKT_TOOBIG: 977 *err = EMSGSIZE; 978 break; 979 980 case ICMPV6_PARAMPROB: 981 *err = EPROTO; 982 fatal = 1; 983 break; 984 985 case ICMPV6_TIME_EXCEED: 986 *err = EHOSTUNREACH; 987 break; 988 } 989 990 return fatal; 991 } 992 EXPORT_SYMBOL(icmpv6_err_convert); 993 994 #ifdef CONFIG_SYSCTL 995 static struct ctl_table ipv6_icmp_table_template[] = { 996 { 997 .procname = "ratelimit", 998 .data = &init_net.ipv6.sysctl.icmpv6_time, 999 .maxlen = sizeof(int), 1000 .mode = 0644, 1001 .proc_handler = proc_dointvec_ms_jiffies, 1002 }, 1003 { }, 1004 }; 1005 1006 struct ctl_table * __net_init ipv6_icmp_sysctl_init(struct net *net) 1007 { 1008 struct ctl_table *table; 1009 1010 table = kmemdup(ipv6_icmp_table_template, 1011 sizeof(ipv6_icmp_table_template), 1012 GFP_KERNEL); 1013 1014 if (table) 1015 table[0].data = &net->ipv6.sysctl.icmpv6_time; 1016 1017 return table; 1018 } 1019 #endif 1020 1021