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 71 #include <asm/uaccess.h> 72 73 /* 74 * The ICMP socket(s). This is the most convenient way to flow control 75 * our ICMP output as well as maintain a clean interface throughout 76 * all layers. All Socketless IP sends will soon be gone. 77 * 78 * On SMP we have one ICMP socket per-cpu. 79 */ 80 static inline struct sock *icmpv6_sk(struct net *net) 81 { 82 return net->ipv6.icmp_sk[smp_processor_id()]; 83 } 84 85 static void icmpv6_err(struct sk_buff *skb, struct inet6_skb_parm *opt, 86 u8 type, u8 code, int offset, __be32 info) 87 { 88 /* icmpv6_notify checks 8 bytes can be pulled, icmp6hdr is 8 bytes */ 89 struct icmp6hdr *icmp6 = (struct icmp6hdr *) (skb->data + offset); 90 struct net *net = dev_net(skb->dev); 91 92 if (type == ICMPV6_PKT_TOOBIG) 93 ip6_update_pmtu(skb, net, info, 0, 0); 94 else if (type == NDISC_REDIRECT) 95 ip6_redirect(skb, net, skb->dev->ifindex, 0); 96 97 if (!(type & ICMPV6_INFOMSG_MASK)) 98 if (icmp6->icmp6_type == ICMPV6_ECHO_REQUEST) 99 ping_err(skb, offset, info); 100 } 101 102 static int icmpv6_rcv(struct sk_buff *skb); 103 104 static const struct inet6_protocol icmpv6_protocol = { 105 .handler = icmpv6_rcv, 106 .err_handler = icmpv6_err, 107 .flags = INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL, 108 }; 109 110 static __inline__ struct sock *icmpv6_xmit_lock(struct net *net) 111 { 112 struct sock *sk; 113 114 local_bh_disable(); 115 116 sk = icmpv6_sk(net); 117 if (unlikely(!spin_trylock(&sk->sk_lock.slock))) { 118 /* This can happen if the output path (f.e. SIT or 119 * ip6ip6 tunnel) signals dst_link_failure() for an 120 * outgoing ICMP6 packet. 121 */ 122 local_bh_enable(); 123 return NULL; 124 } 125 return sk; 126 } 127 128 static __inline__ void icmpv6_xmit_unlock(struct sock *sk) 129 { 130 spin_unlock_bh(&sk->sk_lock.slock); 131 } 132 133 /* 134 * Figure out, may we reply to this packet with icmp error. 135 * 136 * We do not reply, if: 137 * - it was icmp error message. 138 * - it is truncated, so that it is known, that protocol is ICMPV6 139 * (i.e. in the middle of some exthdr) 140 * 141 * --ANK (980726) 142 */ 143 144 static bool is_ineligible(const struct sk_buff *skb) 145 { 146 int ptr = (u8 *)(ipv6_hdr(skb) + 1) - skb->data; 147 int len = skb->len - ptr; 148 __u8 nexthdr = ipv6_hdr(skb)->nexthdr; 149 __be16 frag_off; 150 151 if (len < 0) 152 return true; 153 154 ptr = ipv6_skip_exthdr(skb, ptr, &nexthdr, &frag_off); 155 if (ptr < 0) 156 return false; 157 if (nexthdr == IPPROTO_ICMPV6) { 158 u8 _type, *tp; 159 tp = skb_header_pointer(skb, 160 ptr+offsetof(struct icmp6hdr, icmp6_type), 161 sizeof(_type), &_type); 162 if (tp == NULL || 163 !(*tp & ICMPV6_INFOMSG_MASK)) 164 return true; 165 } 166 return false; 167 } 168 169 /* 170 * Check the ICMP output rate limit 171 */ 172 static inline bool icmpv6_xrlim_allow(struct sock *sk, u8 type, 173 struct flowi6 *fl6) 174 { 175 struct dst_entry *dst; 176 struct net *net = sock_net(sk); 177 bool res = false; 178 179 /* Informational messages are not limited. */ 180 if (type & ICMPV6_INFOMSG_MASK) 181 return true; 182 183 /* Do not limit pmtu discovery, it would break it. */ 184 if (type == ICMPV6_PKT_TOOBIG) 185 return true; 186 187 /* 188 * Look up the output route. 189 * XXX: perhaps the expire for routing entries cloned by 190 * this lookup should be more aggressive (not longer than timeout). 191 */ 192 dst = ip6_route_output(net, sk, fl6); 193 if (dst->error) { 194 IP6_INC_STATS(net, ip6_dst_idev(dst), 195 IPSTATS_MIB_OUTNOROUTES); 196 } else if (dst->dev && (dst->dev->flags&IFF_LOOPBACK)) { 197 res = true; 198 } else { 199 struct rt6_info *rt = (struct rt6_info *)dst; 200 int tmo = net->ipv6.sysctl.icmpv6_time; 201 struct inet_peer *peer; 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 peer = inet_getpeer_v6(net->ipv6.peers, &rt->rt6i_dst.addr, 1); 208 res = inet_peer_xrlim_allow(peer, tmo); 209 if (peer) 210 inet_putpeer(peer); 211 } 212 dst_release(dst); 213 return res; 214 } 215 216 /* 217 * an inline helper for the "simple" if statement below 218 * checks if parameter problem report is caused by an 219 * unrecognized IPv6 option that has the Option Type 220 * highest-order two bits set to 10 221 */ 222 223 static bool opt_unrec(struct sk_buff *skb, __u32 offset) 224 { 225 u8 _optval, *op; 226 227 offset += skb_network_offset(skb); 228 op = skb_header_pointer(skb, offset, sizeof(_optval), &_optval); 229 if (op == NULL) 230 return true; 231 return (*op & 0xC0) == 0x80; 232 } 233 234 int icmpv6_push_pending_frames(struct sock *sk, struct flowi6 *fl6, 235 struct icmp6hdr *thdr, int len) 236 { 237 struct sk_buff *skb; 238 struct icmp6hdr *icmp6h; 239 int err = 0; 240 241 if ((skb = skb_peek(&sk->sk_write_queue)) == NULL) 242 goto out; 243 244 icmp6h = icmp6_hdr(skb); 245 memcpy(icmp6h, thdr, sizeof(struct icmp6hdr)); 246 icmp6h->icmp6_cksum = 0; 247 248 if (skb_queue_len(&sk->sk_write_queue) == 1) { 249 skb->csum = csum_partial(icmp6h, 250 sizeof(struct icmp6hdr), skb->csum); 251 icmp6h->icmp6_cksum = csum_ipv6_magic(&fl6->saddr, 252 &fl6->daddr, 253 len, fl6->flowi6_proto, 254 skb->csum); 255 } else { 256 __wsum tmp_csum = 0; 257 258 skb_queue_walk(&sk->sk_write_queue, skb) { 259 tmp_csum = csum_add(tmp_csum, skb->csum); 260 } 261 262 tmp_csum = csum_partial(icmp6h, 263 sizeof(struct icmp6hdr), tmp_csum); 264 icmp6h->icmp6_cksum = csum_ipv6_magic(&fl6->saddr, 265 &fl6->daddr, 266 len, fl6->flowi6_proto, 267 tmp_csum); 268 } 269 ip6_push_pending_frames(sk); 270 out: 271 return err; 272 } 273 274 struct icmpv6_msg { 275 struct sk_buff *skb; 276 int offset; 277 uint8_t type; 278 }; 279 280 static int icmpv6_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb) 281 { 282 struct icmpv6_msg *msg = (struct icmpv6_msg *) from; 283 struct sk_buff *org_skb = msg->skb; 284 __wsum csum = 0; 285 286 csum = skb_copy_and_csum_bits(org_skb, msg->offset + offset, 287 to, len, csum); 288 skb->csum = csum_block_add(skb->csum, csum, odd); 289 if (!(msg->type & ICMPV6_INFOMSG_MASK)) 290 nf_ct_attach(skb, org_skb); 291 return 0; 292 } 293 294 #if IS_ENABLED(CONFIG_IPV6_MIP6) 295 static void mip6_addr_swap(struct sk_buff *skb) 296 { 297 struct ipv6hdr *iph = ipv6_hdr(skb); 298 struct inet6_skb_parm *opt = IP6CB(skb); 299 struct ipv6_destopt_hao *hao; 300 struct in6_addr tmp; 301 int off; 302 303 if (opt->dsthao) { 304 off = ipv6_find_tlv(skb, opt->dsthao, IPV6_TLV_HAO); 305 if (likely(off >= 0)) { 306 hao = (struct ipv6_destopt_hao *) 307 (skb_network_header(skb) + off); 308 tmp = iph->saddr; 309 iph->saddr = hao->addr; 310 hao->addr = tmp; 311 } 312 } 313 } 314 #else 315 static inline void mip6_addr_swap(struct sk_buff *skb) {} 316 #endif 317 318 struct dst_entry *icmpv6_route_lookup(struct net *net, struct sk_buff *skb, 319 struct sock *sk, struct flowi6 *fl6) 320 { 321 struct dst_entry *dst, *dst2; 322 struct flowi6 fl2; 323 int err; 324 325 err = ip6_dst_lookup(sk, &dst, fl6); 326 if (err) 327 return ERR_PTR(err); 328 329 /* 330 * We won't send icmp if the destination is known 331 * anycast. 332 */ 333 if (((struct rt6_info *)dst)->rt6i_flags & RTF_ANYCAST) { 334 LIMIT_NETDEBUG(KERN_DEBUG "icmp6_send: acast source\n"); 335 dst_release(dst); 336 return ERR_PTR(-EINVAL); 337 } 338 339 /* No need to clone since we're just using its address. */ 340 dst2 = dst; 341 342 dst = xfrm_lookup(net, dst, flowi6_to_flowi(fl6), sk, 0); 343 if (!IS_ERR(dst)) { 344 if (dst != dst2) 345 return dst; 346 } else { 347 if (PTR_ERR(dst) == -EPERM) 348 dst = NULL; 349 else 350 return dst; 351 } 352 353 err = xfrm_decode_session_reverse(skb, flowi6_to_flowi(&fl2), AF_INET6); 354 if (err) 355 goto relookup_failed; 356 357 err = ip6_dst_lookup(sk, &dst2, &fl2); 358 if (err) 359 goto relookup_failed; 360 361 dst2 = xfrm_lookup(net, dst2, flowi6_to_flowi(&fl2), sk, XFRM_LOOKUP_ICMP); 362 if (!IS_ERR(dst2)) { 363 dst_release(dst); 364 dst = dst2; 365 } else { 366 err = PTR_ERR(dst2); 367 if (err == -EPERM) { 368 dst_release(dst); 369 return dst2; 370 } else 371 goto relookup_failed; 372 } 373 374 relookup_failed: 375 if (dst) 376 return dst; 377 return ERR_PTR(err); 378 } 379 380 /* 381 * Send an ICMP message in response to a packet in error 382 */ 383 static void icmp6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info) 384 { 385 struct net *net = dev_net(skb->dev); 386 struct inet6_dev *idev = NULL; 387 struct ipv6hdr *hdr = ipv6_hdr(skb); 388 struct sock *sk; 389 struct ipv6_pinfo *np; 390 const struct in6_addr *saddr = NULL; 391 struct dst_entry *dst; 392 struct icmp6hdr tmp_hdr; 393 struct flowi6 fl6; 394 struct icmpv6_msg msg; 395 int iif = 0; 396 int addr_type = 0; 397 int len; 398 int hlimit; 399 int err = 0; 400 401 if ((u8 *)hdr < skb->head || 402 (skb_network_header(skb) + sizeof(*hdr)) > skb_tail_pointer(skb)) 403 return; 404 405 /* 406 * Make sure we respect the rules 407 * i.e. RFC 1885 2.4(e) 408 * Rule (e.1) is enforced by not using icmp6_send 409 * in any code that processes icmp errors. 410 */ 411 addr_type = ipv6_addr_type(&hdr->daddr); 412 413 if (ipv6_chk_addr(net, &hdr->daddr, skb->dev, 0)) 414 saddr = &hdr->daddr; 415 416 /* 417 * Dest addr check 418 */ 419 420 if ((addr_type & IPV6_ADDR_MULTICAST || skb->pkt_type != PACKET_HOST)) { 421 if (type != ICMPV6_PKT_TOOBIG && 422 !(type == ICMPV6_PARAMPROB && 423 code == ICMPV6_UNK_OPTION && 424 (opt_unrec(skb, info)))) 425 return; 426 427 saddr = NULL; 428 } 429 430 addr_type = ipv6_addr_type(&hdr->saddr); 431 432 /* 433 * Source addr check 434 */ 435 436 if (__ipv6_addr_needs_scope_id(addr_type)) 437 iif = skb->dev->ifindex; 438 439 /* 440 * Must not send error if the source does not uniquely 441 * identify a single node (RFC2463 Section 2.4). 442 * We check unspecified / multicast addresses here, 443 * and anycast addresses will be checked later. 444 */ 445 if ((addr_type == IPV6_ADDR_ANY) || (addr_type & IPV6_ADDR_MULTICAST)) { 446 LIMIT_NETDEBUG(KERN_DEBUG "icmp6_send: addr_any/mcast source\n"); 447 return; 448 } 449 450 /* 451 * Never answer to a ICMP packet. 452 */ 453 if (is_ineligible(skb)) { 454 LIMIT_NETDEBUG(KERN_DEBUG "icmp6_send: no reply to icmp error\n"); 455 return; 456 } 457 458 mip6_addr_swap(skb); 459 460 memset(&fl6, 0, sizeof(fl6)); 461 fl6.flowi6_proto = IPPROTO_ICMPV6; 462 fl6.daddr = hdr->saddr; 463 if (saddr) 464 fl6.saddr = *saddr; 465 fl6.flowi6_oif = iif; 466 fl6.fl6_icmp_type = type; 467 fl6.fl6_icmp_code = code; 468 security_skb_classify_flow(skb, flowi6_to_flowi(&fl6)); 469 470 sk = icmpv6_xmit_lock(net); 471 if (sk == NULL) 472 return; 473 np = inet6_sk(sk); 474 475 if (!icmpv6_xrlim_allow(sk, type, &fl6)) 476 goto out; 477 478 tmp_hdr.icmp6_type = type; 479 tmp_hdr.icmp6_code = code; 480 tmp_hdr.icmp6_cksum = 0; 481 tmp_hdr.icmp6_pointer = htonl(info); 482 483 if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr)) 484 fl6.flowi6_oif = np->mcast_oif; 485 else if (!fl6.flowi6_oif) 486 fl6.flowi6_oif = np->ucast_oif; 487 488 dst = icmpv6_route_lookup(net, skb, sk, &fl6); 489 if (IS_ERR(dst)) 490 goto out; 491 492 if (ipv6_addr_is_multicast(&fl6.daddr)) 493 hlimit = np->mcast_hops; 494 else 495 hlimit = np->hop_limit; 496 if (hlimit < 0) 497 hlimit = ip6_dst_hoplimit(dst); 498 499 msg.skb = skb; 500 msg.offset = skb_network_offset(skb); 501 msg.type = type; 502 503 len = skb->len - msg.offset; 504 len = min_t(unsigned int, len, IPV6_MIN_MTU - sizeof(struct ipv6hdr) -sizeof(struct icmp6hdr)); 505 if (len < 0) { 506 LIMIT_NETDEBUG(KERN_DEBUG "icmp: len problem\n"); 507 goto out_dst_release; 508 } 509 510 rcu_read_lock(); 511 idev = __in6_dev_get(skb->dev); 512 513 err = ip6_append_data(sk, icmpv6_getfrag, &msg, 514 len + sizeof(struct icmp6hdr), 515 sizeof(struct icmp6hdr), hlimit, 516 np->tclass, NULL, &fl6, (struct rt6_info *)dst, 517 MSG_DONTWAIT, np->dontfrag); 518 if (err) { 519 ICMP6_INC_STATS_BH(net, idev, ICMP6_MIB_OUTERRORS); 520 ip6_flush_pending_frames(sk); 521 } else { 522 err = icmpv6_push_pending_frames(sk, &fl6, &tmp_hdr, 523 len + sizeof(struct icmp6hdr)); 524 } 525 rcu_read_unlock(); 526 out_dst_release: 527 dst_release(dst); 528 out: 529 icmpv6_xmit_unlock(sk); 530 } 531 532 /* Slightly more convenient version of icmp6_send. 533 */ 534 void icmpv6_param_prob(struct sk_buff *skb, u8 code, int pos) 535 { 536 icmp6_send(skb, ICMPV6_PARAMPROB, code, pos); 537 kfree_skb(skb); 538 } 539 540 static void icmpv6_echo_reply(struct sk_buff *skb) 541 { 542 struct net *net = dev_net(skb->dev); 543 struct sock *sk; 544 struct inet6_dev *idev; 545 struct ipv6_pinfo *np; 546 const struct in6_addr *saddr = NULL; 547 struct icmp6hdr *icmph = icmp6_hdr(skb); 548 struct icmp6hdr tmp_hdr; 549 struct flowi6 fl6; 550 struct icmpv6_msg msg; 551 struct dst_entry *dst; 552 int err = 0; 553 int hlimit; 554 555 saddr = &ipv6_hdr(skb)->daddr; 556 557 if (!ipv6_unicast_destination(skb)) 558 saddr = NULL; 559 560 memcpy(&tmp_hdr, icmph, sizeof(tmp_hdr)); 561 tmp_hdr.icmp6_type = ICMPV6_ECHO_REPLY; 562 563 memset(&fl6, 0, sizeof(fl6)); 564 fl6.flowi6_proto = IPPROTO_ICMPV6; 565 fl6.daddr = ipv6_hdr(skb)->saddr; 566 if (saddr) 567 fl6.saddr = *saddr; 568 fl6.flowi6_oif = skb->dev->ifindex; 569 fl6.fl6_icmp_type = ICMPV6_ECHO_REPLY; 570 security_skb_classify_flow(skb, flowi6_to_flowi(&fl6)); 571 572 sk = icmpv6_xmit_lock(net); 573 if (sk == NULL) 574 return; 575 np = inet6_sk(sk); 576 577 if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr)) 578 fl6.flowi6_oif = np->mcast_oif; 579 else if (!fl6.flowi6_oif) 580 fl6.flowi6_oif = np->ucast_oif; 581 582 err = ip6_dst_lookup(sk, &dst, &fl6); 583 if (err) 584 goto out; 585 dst = xfrm_lookup(net, dst, flowi6_to_flowi(&fl6), sk, 0); 586 if (IS_ERR(dst)) 587 goto out; 588 589 if (ipv6_addr_is_multicast(&fl6.daddr)) 590 hlimit = np->mcast_hops; 591 else 592 hlimit = np->hop_limit; 593 if (hlimit < 0) 594 hlimit = ip6_dst_hoplimit(dst); 595 596 idev = __in6_dev_get(skb->dev); 597 598 msg.skb = skb; 599 msg.offset = 0; 600 msg.type = ICMPV6_ECHO_REPLY; 601 602 err = ip6_append_data(sk, icmpv6_getfrag, &msg, skb->len + sizeof(struct icmp6hdr), 603 sizeof(struct icmp6hdr), hlimit, np->tclass, NULL, &fl6, 604 (struct rt6_info *)dst, MSG_DONTWAIT, 605 np->dontfrag); 606 607 if (err) { 608 ICMP6_INC_STATS_BH(net, idev, ICMP6_MIB_OUTERRORS); 609 ip6_flush_pending_frames(sk); 610 } else { 611 err = icmpv6_push_pending_frames(sk, &fl6, &tmp_hdr, 612 skb->len + sizeof(struct icmp6hdr)); 613 } 614 dst_release(dst); 615 out: 616 icmpv6_xmit_unlock(sk); 617 } 618 619 void icmpv6_notify(struct sk_buff *skb, u8 type, u8 code, __be32 info) 620 { 621 const struct inet6_protocol *ipprot; 622 int inner_offset; 623 __be16 frag_off; 624 u8 nexthdr; 625 626 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr))) 627 return; 628 629 nexthdr = ((struct ipv6hdr *)skb->data)->nexthdr; 630 if (ipv6_ext_hdr(nexthdr)) { 631 /* now skip over extension headers */ 632 inner_offset = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), 633 &nexthdr, &frag_off); 634 if (inner_offset<0) 635 return; 636 } else { 637 inner_offset = sizeof(struct ipv6hdr); 638 } 639 640 /* Checkin header including 8 bytes of inner protocol header. */ 641 if (!pskb_may_pull(skb, inner_offset+8)) 642 return; 643 644 /* BUGGG_FUTURE: we should try to parse exthdrs in this packet. 645 Without this we will not able f.e. to make source routed 646 pmtu discovery. 647 Corresponding argument (opt) to notifiers is already added. 648 --ANK (980726) 649 */ 650 651 rcu_read_lock(); 652 ipprot = rcu_dereference(inet6_protos[nexthdr]); 653 if (ipprot && ipprot->err_handler) 654 ipprot->err_handler(skb, NULL, type, code, inner_offset, info); 655 rcu_read_unlock(); 656 657 raw6_icmp_error(skb, nexthdr, type, code, inner_offset, info); 658 } 659 660 /* 661 * Handle icmp messages 662 */ 663 664 static int icmpv6_rcv(struct sk_buff *skb) 665 { 666 struct net_device *dev = skb->dev; 667 struct inet6_dev *idev = __in6_dev_get(dev); 668 const struct in6_addr *saddr, *daddr; 669 struct icmp6hdr *hdr; 670 u8 type; 671 672 if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) { 673 struct sec_path *sp = skb_sec_path(skb); 674 int nh; 675 676 if (!(sp && sp->xvec[sp->len - 1]->props.flags & 677 XFRM_STATE_ICMP)) 678 goto drop_no_count; 679 680 if (!pskb_may_pull(skb, sizeof(*hdr) + sizeof(struct ipv6hdr))) 681 goto drop_no_count; 682 683 nh = skb_network_offset(skb); 684 skb_set_network_header(skb, sizeof(*hdr)); 685 686 if (!xfrm6_policy_check_reverse(NULL, XFRM_POLICY_IN, skb)) 687 goto drop_no_count; 688 689 skb_set_network_header(skb, nh); 690 } 691 692 ICMP6_INC_STATS_BH(dev_net(dev), idev, ICMP6_MIB_INMSGS); 693 694 saddr = &ipv6_hdr(skb)->saddr; 695 daddr = &ipv6_hdr(skb)->daddr; 696 697 /* Perform checksum. */ 698 switch (skb->ip_summed) { 699 case CHECKSUM_COMPLETE: 700 if (!csum_ipv6_magic(saddr, daddr, skb->len, IPPROTO_ICMPV6, 701 skb->csum)) 702 break; 703 /* fall through */ 704 case CHECKSUM_NONE: 705 skb->csum = ~csum_unfold(csum_ipv6_magic(saddr, daddr, skb->len, 706 IPPROTO_ICMPV6, 0)); 707 if (__skb_checksum_complete(skb)) { 708 LIMIT_NETDEBUG(KERN_DEBUG 709 "ICMPv6 checksum failed [%pI6c > %pI6c]\n", 710 saddr, daddr); 711 goto csum_error; 712 } 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 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