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/protocol.h> 61 #include <net/raw.h> 62 #include <net/rawv6.h> 63 #include <net/transp_v6.h> 64 #include <net/ip6_route.h> 65 #include <net/addrconf.h> 66 #include <net/icmp.h> 67 #include <net/xfrm.h> 68 #include <net/inet_common.h> 69 70 #include <asm/uaccess.h> 71 72 /* 73 * The ICMP socket(s). This is the most convenient way to flow control 74 * our ICMP output as well as maintain a clean interface throughout 75 * all layers. All Socketless IP sends will soon be gone. 76 * 77 * On SMP we have one ICMP socket per-cpu. 78 */ 79 static inline struct sock *icmpv6_sk(struct net *net) 80 { 81 return net->ipv6.icmp_sk[smp_processor_id()]; 82 } 83 84 static int icmpv6_rcv(struct sk_buff *skb); 85 86 static const struct inet6_protocol icmpv6_protocol = { 87 .handler = icmpv6_rcv, 88 .flags = INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL, 89 }; 90 91 static __inline__ struct sock *icmpv6_xmit_lock(struct net *net) 92 { 93 struct sock *sk; 94 95 local_bh_disable(); 96 97 sk = icmpv6_sk(net); 98 if (unlikely(!spin_trylock(&sk->sk_lock.slock))) { 99 /* This can happen if the output path (f.e. SIT or 100 * ip6ip6 tunnel) signals dst_link_failure() for an 101 * outgoing ICMP6 packet. 102 */ 103 local_bh_enable(); 104 return NULL; 105 } 106 return sk; 107 } 108 109 static __inline__ void icmpv6_xmit_unlock(struct sock *sk) 110 { 111 spin_unlock_bh(&sk->sk_lock.slock); 112 } 113 114 /* 115 * Slightly more convenient version of icmpv6_send. 116 */ 117 void icmpv6_param_prob(struct sk_buff *skb, u8 code, int pos) 118 { 119 icmpv6_send(skb, ICMPV6_PARAMPROB, code, pos); 120 kfree_skb(skb); 121 } 122 123 /* 124 * Figure out, may we reply to this packet with icmp error. 125 * 126 * We do not reply, if: 127 * - it was icmp error message. 128 * - it is truncated, so that it is known, that protocol is ICMPV6 129 * (i.e. in the middle of some exthdr) 130 * 131 * --ANK (980726) 132 */ 133 134 static bool is_ineligible(const struct sk_buff *skb) 135 { 136 int ptr = (u8 *)(ipv6_hdr(skb) + 1) - skb->data; 137 int len = skb->len - ptr; 138 __u8 nexthdr = ipv6_hdr(skb)->nexthdr; 139 __be16 frag_off; 140 141 if (len < 0) 142 return true; 143 144 ptr = ipv6_skip_exthdr(skb, ptr, &nexthdr, &frag_off); 145 if (ptr < 0) 146 return false; 147 if (nexthdr == IPPROTO_ICMPV6) { 148 u8 _type, *tp; 149 tp = skb_header_pointer(skb, 150 ptr+offsetof(struct icmp6hdr, icmp6_type), 151 sizeof(_type), &_type); 152 if (tp == NULL || 153 !(*tp & ICMPV6_INFOMSG_MASK)) 154 return true; 155 } 156 return false; 157 } 158 159 /* 160 * Check the ICMP output rate limit 161 */ 162 static inline bool icmpv6_xrlim_allow(struct sock *sk, u8 type, 163 struct flowi6 *fl6) 164 { 165 struct dst_entry *dst; 166 struct net *net = sock_net(sk); 167 bool res = false; 168 169 /* Informational messages are not limited. */ 170 if (type & ICMPV6_INFOMSG_MASK) 171 return true; 172 173 /* Do not limit pmtu discovery, it would break it. */ 174 if (type == ICMPV6_PKT_TOOBIG) 175 return true; 176 177 /* 178 * Look up the output route. 179 * XXX: perhaps the expire for routing entries cloned by 180 * this lookup should be more aggressive (not longer than timeout). 181 */ 182 dst = ip6_route_output(net, sk, fl6); 183 if (dst->error) { 184 IP6_INC_STATS(net, ip6_dst_idev(dst), 185 IPSTATS_MIB_OUTNOROUTES); 186 } else if (dst->dev && (dst->dev->flags&IFF_LOOPBACK)) { 187 res = true; 188 } else { 189 struct rt6_info *rt = (struct rt6_info *)dst; 190 int tmo = net->ipv6.sysctl.icmpv6_time; 191 struct inet_peer *peer; 192 193 /* Give more bandwidth to wider prefixes. */ 194 if (rt->rt6i_dst.plen < 128) 195 tmo >>= ((128 - rt->rt6i_dst.plen)>>5); 196 197 peer = rt6_get_peer_create(rt); 198 res = inet_peer_xrlim_allow(peer, tmo); 199 } 200 dst_release(dst); 201 return res; 202 } 203 204 /* 205 * an inline helper for the "simple" if statement below 206 * checks if parameter problem report is caused by an 207 * unrecognized IPv6 option that has the Option Type 208 * highest-order two bits set to 10 209 */ 210 211 static bool opt_unrec(struct sk_buff *skb, __u32 offset) 212 { 213 u8 _optval, *op; 214 215 offset += skb_network_offset(skb); 216 op = skb_header_pointer(skb, offset, sizeof(_optval), &_optval); 217 if (op == NULL) 218 return true; 219 return (*op & 0xC0) == 0x80; 220 } 221 222 static int icmpv6_push_pending_frames(struct sock *sk, struct flowi6 *fl6, struct icmp6hdr *thdr, int len) 223 { 224 struct sk_buff *skb; 225 struct icmp6hdr *icmp6h; 226 int err = 0; 227 228 if ((skb = skb_peek(&sk->sk_write_queue)) == NULL) 229 goto out; 230 231 icmp6h = icmp6_hdr(skb); 232 memcpy(icmp6h, thdr, sizeof(struct icmp6hdr)); 233 icmp6h->icmp6_cksum = 0; 234 235 if (skb_queue_len(&sk->sk_write_queue) == 1) { 236 skb->csum = csum_partial(icmp6h, 237 sizeof(struct icmp6hdr), skb->csum); 238 icmp6h->icmp6_cksum = csum_ipv6_magic(&fl6->saddr, 239 &fl6->daddr, 240 len, fl6->flowi6_proto, 241 skb->csum); 242 } else { 243 __wsum tmp_csum = 0; 244 245 skb_queue_walk(&sk->sk_write_queue, skb) { 246 tmp_csum = csum_add(tmp_csum, skb->csum); 247 } 248 249 tmp_csum = csum_partial(icmp6h, 250 sizeof(struct icmp6hdr), tmp_csum); 251 icmp6h->icmp6_cksum = csum_ipv6_magic(&fl6->saddr, 252 &fl6->daddr, 253 len, fl6->flowi6_proto, 254 tmp_csum); 255 } 256 ip6_push_pending_frames(sk); 257 out: 258 return err; 259 } 260 261 struct icmpv6_msg { 262 struct sk_buff *skb; 263 int offset; 264 uint8_t type; 265 }; 266 267 static int icmpv6_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb) 268 { 269 struct icmpv6_msg *msg = (struct icmpv6_msg *) from; 270 struct sk_buff *org_skb = msg->skb; 271 __wsum csum = 0; 272 273 csum = skb_copy_and_csum_bits(org_skb, msg->offset + offset, 274 to, len, csum); 275 skb->csum = csum_block_add(skb->csum, csum, odd); 276 if (!(msg->type & ICMPV6_INFOMSG_MASK)) 277 nf_ct_attach(skb, org_skb); 278 return 0; 279 } 280 281 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE) 282 static void mip6_addr_swap(struct sk_buff *skb) 283 { 284 struct ipv6hdr *iph = ipv6_hdr(skb); 285 struct inet6_skb_parm *opt = IP6CB(skb); 286 struct ipv6_destopt_hao *hao; 287 struct in6_addr tmp; 288 int off; 289 290 if (opt->dsthao) { 291 off = ipv6_find_tlv(skb, opt->dsthao, IPV6_TLV_HAO); 292 if (likely(off >= 0)) { 293 hao = (struct ipv6_destopt_hao *) 294 (skb_network_header(skb) + off); 295 tmp = iph->saddr; 296 iph->saddr = hao->addr; 297 hao->addr = tmp; 298 } 299 } 300 } 301 #else 302 static inline void mip6_addr_swap(struct sk_buff *skb) {} 303 #endif 304 305 static struct dst_entry *icmpv6_route_lookup(struct net *net, struct sk_buff *skb, 306 struct sock *sk, struct flowi6 *fl6) 307 { 308 struct dst_entry *dst, *dst2; 309 struct flowi6 fl2; 310 int err; 311 312 err = ip6_dst_lookup(sk, &dst, fl6); 313 if (err) 314 return ERR_PTR(err); 315 316 /* 317 * We won't send icmp if the destination is known 318 * anycast. 319 */ 320 if (((struct rt6_info *)dst)->rt6i_flags & RTF_ANYCAST) { 321 LIMIT_NETDEBUG(KERN_DEBUG "icmpv6_send: acast source\n"); 322 dst_release(dst); 323 return ERR_PTR(-EINVAL); 324 } 325 326 /* No need to clone since we're just using its address. */ 327 dst2 = dst; 328 329 dst = xfrm_lookup(net, dst, flowi6_to_flowi(fl6), sk, 0); 330 if (!IS_ERR(dst)) { 331 if (dst != dst2) 332 return dst; 333 } else { 334 if (PTR_ERR(dst) == -EPERM) 335 dst = NULL; 336 else 337 return dst; 338 } 339 340 err = xfrm_decode_session_reverse(skb, flowi6_to_flowi(&fl2), AF_INET6); 341 if (err) 342 goto relookup_failed; 343 344 err = ip6_dst_lookup(sk, &dst2, &fl2); 345 if (err) 346 goto relookup_failed; 347 348 dst2 = xfrm_lookup(net, dst2, flowi6_to_flowi(&fl2), sk, XFRM_LOOKUP_ICMP); 349 if (!IS_ERR(dst2)) { 350 dst_release(dst); 351 dst = dst2; 352 } else { 353 err = PTR_ERR(dst2); 354 if (err == -EPERM) { 355 dst_release(dst); 356 return dst2; 357 } else 358 goto relookup_failed; 359 } 360 361 relookup_failed: 362 if (dst) 363 return dst; 364 return ERR_PTR(err); 365 } 366 367 /* 368 * Send an ICMP message in response to a packet in error 369 */ 370 void icmpv6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info) 371 { 372 struct net *net = dev_net(skb->dev); 373 struct inet6_dev *idev = NULL; 374 struct ipv6hdr *hdr = ipv6_hdr(skb); 375 struct sock *sk; 376 struct ipv6_pinfo *np; 377 const struct in6_addr *saddr = NULL; 378 struct dst_entry *dst; 379 struct icmp6hdr tmp_hdr; 380 struct flowi6 fl6; 381 struct icmpv6_msg msg; 382 int iif = 0; 383 int addr_type = 0; 384 int len; 385 int hlimit; 386 int err = 0; 387 388 if ((u8 *)hdr < skb->head || 389 (skb->network_header + sizeof(*hdr)) > skb->tail) 390 return; 391 392 /* 393 * Make sure we respect the rules 394 * i.e. RFC 1885 2.4(e) 395 * Rule (e.1) is enforced by not using icmpv6_send 396 * in any code that processes icmp errors. 397 */ 398 addr_type = ipv6_addr_type(&hdr->daddr); 399 400 if (ipv6_chk_addr(net, &hdr->daddr, skb->dev, 0)) 401 saddr = &hdr->daddr; 402 403 /* 404 * Dest addr check 405 */ 406 407 if ((addr_type & IPV6_ADDR_MULTICAST || skb->pkt_type != PACKET_HOST)) { 408 if (type != ICMPV6_PKT_TOOBIG && 409 !(type == ICMPV6_PARAMPROB && 410 code == ICMPV6_UNK_OPTION && 411 (opt_unrec(skb, info)))) 412 return; 413 414 saddr = NULL; 415 } 416 417 addr_type = ipv6_addr_type(&hdr->saddr); 418 419 /* 420 * Source addr check 421 */ 422 423 if (addr_type & IPV6_ADDR_LINKLOCAL) 424 iif = skb->dev->ifindex; 425 426 /* 427 * Must not send error if the source does not uniquely 428 * identify a single node (RFC2463 Section 2.4). 429 * We check unspecified / multicast addresses here, 430 * and anycast addresses will be checked later. 431 */ 432 if ((addr_type == IPV6_ADDR_ANY) || (addr_type & IPV6_ADDR_MULTICAST)) { 433 LIMIT_NETDEBUG(KERN_DEBUG "icmpv6_send: addr_any/mcast source\n"); 434 return; 435 } 436 437 /* 438 * Never answer to a ICMP packet. 439 */ 440 if (is_ineligible(skb)) { 441 LIMIT_NETDEBUG(KERN_DEBUG "icmpv6_send: no reply to icmp error\n"); 442 return; 443 } 444 445 mip6_addr_swap(skb); 446 447 memset(&fl6, 0, sizeof(fl6)); 448 fl6.flowi6_proto = IPPROTO_ICMPV6; 449 fl6.daddr = hdr->saddr; 450 if (saddr) 451 fl6.saddr = *saddr; 452 fl6.flowi6_oif = iif; 453 fl6.fl6_icmp_type = type; 454 fl6.fl6_icmp_code = code; 455 security_skb_classify_flow(skb, flowi6_to_flowi(&fl6)); 456 457 sk = icmpv6_xmit_lock(net); 458 if (sk == NULL) 459 return; 460 np = inet6_sk(sk); 461 462 if (!icmpv6_xrlim_allow(sk, type, &fl6)) 463 goto out; 464 465 tmp_hdr.icmp6_type = type; 466 tmp_hdr.icmp6_code = code; 467 tmp_hdr.icmp6_cksum = 0; 468 tmp_hdr.icmp6_pointer = htonl(info); 469 470 if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr)) 471 fl6.flowi6_oif = np->mcast_oif; 472 else if (!fl6.flowi6_oif) 473 fl6.flowi6_oif = np->ucast_oif; 474 475 dst = icmpv6_route_lookup(net, skb, sk, &fl6); 476 if (IS_ERR(dst)) 477 goto out; 478 479 if (ipv6_addr_is_multicast(&fl6.daddr)) 480 hlimit = np->mcast_hops; 481 else 482 hlimit = np->hop_limit; 483 if (hlimit < 0) 484 hlimit = ip6_dst_hoplimit(dst); 485 486 msg.skb = skb; 487 msg.offset = skb_network_offset(skb); 488 msg.type = type; 489 490 len = skb->len - msg.offset; 491 len = min_t(unsigned int, len, IPV6_MIN_MTU - sizeof(struct ipv6hdr) -sizeof(struct icmp6hdr)); 492 if (len < 0) { 493 LIMIT_NETDEBUG(KERN_DEBUG "icmp: len problem\n"); 494 goto out_dst_release; 495 } 496 497 rcu_read_lock(); 498 idev = __in6_dev_get(skb->dev); 499 500 err = ip6_append_data(sk, icmpv6_getfrag, &msg, 501 len + sizeof(struct icmp6hdr), 502 sizeof(struct icmp6hdr), hlimit, 503 np->tclass, NULL, &fl6, (struct rt6_info *)dst, 504 MSG_DONTWAIT, np->dontfrag); 505 if (err) { 506 ICMP6_INC_STATS_BH(net, idev, ICMP6_MIB_OUTERRORS); 507 ip6_flush_pending_frames(sk); 508 } else { 509 err = icmpv6_push_pending_frames(sk, &fl6, &tmp_hdr, 510 len + sizeof(struct icmp6hdr)); 511 } 512 rcu_read_unlock(); 513 out_dst_release: 514 dst_release(dst); 515 out: 516 icmpv6_xmit_unlock(sk); 517 } 518 EXPORT_SYMBOL(icmpv6_send); 519 520 static void icmpv6_echo_reply(struct sk_buff *skb) 521 { 522 struct net *net = dev_net(skb->dev); 523 struct sock *sk; 524 struct inet6_dev *idev; 525 struct ipv6_pinfo *np; 526 const struct in6_addr *saddr = NULL; 527 struct icmp6hdr *icmph = icmp6_hdr(skb); 528 struct icmp6hdr tmp_hdr; 529 struct flowi6 fl6; 530 struct icmpv6_msg msg; 531 struct dst_entry *dst; 532 int err = 0; 533 int hlimit; 534 535 saddr = &ipv6_hdr(skb)->daddr; 536 537 if (!ipv6_unicast_destination(skb)) 538 saddr = NULL; 539 540 memcpy(&tmp_hdr, icmph, sizeof(tmp_hdr)); 541 tmp_hdr.icmp6_type = ICMPV6_ECHO_REPLY; 542 543 memset(&fl6, 0, sizeof(fl6)); 544 fl6.flowi6_proto = IPPROTO_ICMPV6; 545 fl6.daddr = ipv6_hdr(skb)->saddr; 546 if (saddr) 547 fl6.saddr = *saddr; 548 fl6.flowi6_oif = skb->dev->ifindex; 549 fl6.fl6_icmp_type = ICMPV6_ECHO_REPLY; 550 security_skb_classify_flow(skb, flowi6_to_flowi(&fl6)); 551 552 sk = icmpv6_xmit_lock(net); 553 if (sk == NULL) 554 return; 555 np = inet6_sk(sk); 556 557 if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr)) 558 fl6.flowi6_oif = np->mcast_oif; 559 else if (!fl6.flowi6_oif) 560 fl6.flowi6_oif = np->ucast_oif; 561 562 err = ip6_dst_lookup(sk, &dst, &fl6); 563 if (err) 564 goto out; 565 dst = xfrm_lookup(net, dst, flowi6_to_flowi(&fl6), sk, 0); 566 if (IS_ERR(dst)) 567 goto out; 568 569 if (ipv6_addr_is_multicast(&fl6.daddr)) 570 hlimit = np->mcast_hops; 571 else 572 hlimit = np->hop_limit; 573 if (hlimit < 0) 574 hlimit = ip6_dst_hoplimit(dst); 575 576 idev = __in6_dev_get(skb->dev); 577 578 msg.skb = skb; 579 msg.offset = 0; 580 msg.type = ICMPV6_ECHO_REPLY; 581 582 err = ip6_append_data(sk, icmpv6_getfrag, &msg, skb->len + sizeof(struct icmp6hdr), 583 sizeof(struct icmp6hdr), hlimit, np->tclass, NULL, &fl6, 584 (struct rt6_info *)dst, MSG_DONTWAIT, 585 np->dontfrag); 586 587 if (err) { 588 ICMP6_INC_STATS_BH(net, idev, ICMP6_MIB_OUTERRORS); 589 ip6_flush_pending_frames(sk); 590 } else { 591 err = icmpv6_push_pending_frames(sk, &fl6, &tmp_hdr, 592 skb->len + sizeof(struct icmp6hdr)); 593 } 594 dst_release(dst); 595 out: 596 icmpv6_xmit_unlock(sk); 597 } 598 599 static void icmpv6_notify(struct sk_buff *skb, u8 type, u8 code, __be32 info) 600 { 601 const struct inet6_protocol *ipprot; 602 int inner_offset; 603 int hash; 604 u8 nexthdr; 605 __be16 frag_off; 606 607 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr))) 608 return; 609 610 nexthdr = ((struct ipv6hdr *)skb->data)->nexthdr; 611 if (ipv6_ext_hdr(nexthdr)) { 612 /* now skip over extension headers */ 613 inner_offset = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), 614 &nexthdr, &frag_off); 615 if (inner_offset<0) 616 return; 617 } else { 618 inner_offset = sizeof(struct ipv6hdr); 619 } 620 621 /* Checkin header including 8 bytes of inner protocol header. */ 622 if (!pskb_may_pull(skb, inner_offset+8)) 623 return; 624 625 /* BUGGG_FUTURE: we should try to parse exthdrs in this packet. 626 Without this we will not able f.e. to make source routed 627 pmtu discovery. 628 Corresponding argument (opt) to notifiers is already added. 629 --ANK (980726) 630 */ 631 632 hash = nexthdr & (MAX_INET_PROTOS - 1); 633 634 rcu_read_lock(); 635 ipprot = rcu_dereference(inet6_protos[hash]); 636 if (ipprot && ipprot->err_handler) 637 ipprot->err_handler(skb, NULL, type, code, inner_offset, info); 638 rcu_read_unlock(); 639 640 raw6_icmp_error(skb, nexthdr, type, code, inner_offset, info); 641 } 642 643 /* 644 * Handle icmp messages 645 */ 646 647 static int icmpv6_rcv(struct sk_buff *skb) 648 { 649 struct net_device *dev = skb->dev; 650 struct inet6_dev *idev = __in6_dev_get(dev); 651 const struct in6_addr *saddr, *daddr; 652 const struct ipv6hdr *orig_hdr; 653 struct icmp6hdr *hdr; 654 u8 type; 655 656 if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) { 657 struct sec_path *sp = skb_sec_path(skb); 658 int nh; 659 660 if (!(sp && sp->xvec[sp->len - 1]->props.flags & 661 XFRM_STATE_ICMP)) 662 goto drop_no_count; 663 664 if (!pskb_may_pull(skb, sizeof(*hdr) + sizeof(*orig_hdr))) 665 goto drop_no_count; 666 667 nh = skb_network_offset(skb); 668 skb_set_network_header(skb, sizeof(*hdr)); 669 670 if (!xfrm6_policy_check_reverse(NULL, XFRM_POLICY_IN, skb)) 671 goto drop_no_count; 672 673 skb_set_network_header(skb, nh); 674 } 675 676 ICMP6_INC_STATS_BH(dev_net(dev), idev, ICMP6_MIB_INMSGS); 677 678 saddr = &ipv6_hdr(skb)->saddr; 679 daddr = &ipv6_hdr(skb)->daddr; 680 681 /* Perform checksum. */ 682 switch (skb->ip_summed) { 683 case CHECKSUM_COMPLETE: 684 if (!csum_ipv6_magic(saddr, daddr, skb->len, IPPROTO_ICMPV6, 685 skb->csum)) 686 break; 687 /* fall through */ 688 case CHECKSUM_NONE: 689 skb->csum = ~csum_unfold(csum_ipv6_magic(saddr, daddr, skb->len, 690 IPPROTO_ICMPV6, 0)); 691 if (__skb_checksum_complete(skb)) { 692 LIMIT_NETDEBUG(KERN_DEBUG "ICMPv6 checksum failed [%pI6 > %pI6]\n", 693 saddr, daddr); 694 goto discard_it; 695 } 696 } 697 698 if (!pskb_pull(skb, sizeof(*hdr))) 699 goto discard_it; 700 701 hdr = icmp6_hdr(skb); 702 703 type = hdr->icmp6_type; 704 705 ICMP6MSGIN_INC_STATS_BH(dev_net(dev), idev, type); 706 707 switch (type) { 708 case ICMPV6_ECHO_REQUEST: 709 icmpv6_echo_reply(skb); 710 break; 711 712 case ICMPV6_ECHO_REPLY: 713 /* we couldn't care less */ 714 break; 715 716 case ICMPV6_PKT_TOOBIG: 717 /* BUGGG_FUTURE: if packet contains rthdr, we cannot update 718 standard destination cache. Seems, only "advanced" 719 destination cache will allow to solve this problem 720 --ANK (980726) 721 */ 722 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr))) 723 goto discard_it; 724 hdr = icmp6_hdr(skb); 725 orig_hdr = (struct ipv6hdr *) (hdr + 1); 726 rt6_pmtu_discovery(&orig_hdr->daddr, &orig_hdr->saddr, dev, 727 ntohl(hdr->icmp6_mtu)); 728 729 /* 730 * Drop through to notify 731 */ 732 733 case ICMPV6_DEST_UNREACH: 734 case ICMPV6_TIME_EXCEED: 735 case ICMPV6_PARAMPROB: 736 icmpv6_notify(skb, type, hdr->icmp6_code, hdr->icmp6_mtu); 737 break; 738 739 case NDISC_ROUTER_SOLICITATION: 740 case NDISC_ROUTER_ADVERTISEMENT: 741 case NDISC_NEIGHBOUR_SOLICITATION: 742 case NDISC_NEIGHBOUR_ADVERTISEMENT: 743 case NDISC_REDIRECT: 744 ndisc_rcv(skb); 745 break; 746 747 case ICMPV6_MGM_QUERY: 748 igmp6_event_query(skb); 749 break; 750 751 case ICMPV6_MGM_REPORT: 752 igmp6_event_report(skb); 753 break; 754 755 case ICMPV6_MGM_REDUCTION: 756 case ICMPV6_NI_QUERY: 757 case ICMPV6_NI_REPLY: 758 case ICMPV6_MLD2_REPORT: 759 case ICMPV6_DHAAD_REQUEST: 760 case ICMPV6_DHAAD_REPLY: 761 case ICMPV6_MOBILE_PREFIX_SOL: 762 case ICMPV6_MOBILE_PREFIX_ADV: 763 break; 764 765 default: 766 LIMIT_NETDEBUG(KERN_DEBUG "icmpv6: msg of unknown type\n"); 767 768 /* informational */ 769 if (type & ICMPV6_INFOMSG_MASK) 770 break; 771 772 /* 773 * error of unknown type. 774 * must pass to upper level 775 */ 776 777 icmpv6_notify(skb, type, hdr->icmp6_code, hdr->icmp6_mtu); 778 } 779 780 kfree_skb(skb); 781 return 0; 782 783 discard_it: 784 ICMP6_INC_STATS_BH(dev_net(dev), idev, ICMP6_MIB_INERRORS); 785 drop_no_count: 786 kfree_skb(skb); 787 return 0; 788 } 789 790 void icmpv6_flow_init(struct sock *sk, struct flowi6 *fl6, 791 u8 type, 792 const struct in6_addr *saddr, 793 const struct in6_addr *daddr, 794 int oif) 795 { 796 memset(fl6, 0, sizeof(*fl6)); 797 fl6->saddr = *saddr; 798 fl6->daddr = *daddr; 799 fl6->flowi6_proto = IPPROTO_ICMPV6; 800 fl6->fl6_icmp_type = type; 801 fl6->fl6_icmp_code = 0; 802 fl6->flowi6_oif = oif; 803 security_sk_classify_flow(sk, flowi6_to_flowi(fl6)); 804 } 805 806 /* 807 * Special lock-class for __icmpv6_sk: 808 */ 809 static struct lock_class_key icmpv6_socket_sk_dst_lock_key; 810 811 static int __net_init icmpv6_sk_init(struct net *net) 812 { 813 struct sock *sk; 814 int err, i, j; 815 816 net->ipv6.icmp_sk = 817 kzalloc(nr_cpu_ids * sizeof(struct sock *), GFP_KERNEL); 818 if (net->ipv6.icmp_sk == NULL) 819 return -ENOMEM; 820 821 for_each_possible_cpu(i) { 822 err = inet_ctl_sock_create(&sk, PF_INET6, 823 SOCK_RAW, IPPROTO_ICMPV6, net); 824 if (err < 0) { 825 pr_err("Failed to initialize the ICMP6 control socket (err %d)\n", 826 err); 827 goto fail; 828 } 829 830 net->ipv6.icmp_sk[i] = sk; 831 832 /* 833 * Split off their lock-class, because sk->sk_dst_lock 834 * gets used from softirqs, which is safe for 835 * __icmpv6_sk (because those never get directly used 836 * via userspace syscalls), but unsafe for normal sockets. 837 */ 838 lockdep_set_class(&sk->sk_dst_lock, 839 &icmpv6_socket_sk_dst_lock_key); 840 841 /* Enough space for 2 64K ICMP packets, including 842 * sk_buff struct overhead. 843 */ 844 sk->sk_sndbuf = 2 * SKB_TRUESIZE(64 * 1024); 845 } 846 return 0; 847 848 fail: 849 for (j = 0; j < i; j++) 850 inet_ctl_sock_destroy(net->ipv6.icmp_sk[j]); 851 kfree(net->ipv6.icmp_sk); 852 return err; 853 } 854 855 static void __net_exit icmpv6_sk_exit(struct net *net) 856 { 857 int i; 858 859 for_each_possible_cpu(i) { 860 inet_ctl_sock_destroy(net->ipv6.icmp_sk[i]); 861 } 862 kfree(net->ipv6.icmp_sk); 863 } 864 865 static struct pernet_operations icmpv6_sk_ops = { 866 .init = icmpv6_sk_init, 867 .exit = icmpv6_sk_exit, 868 }; 869 870 int __init icmpv6_init(void) 871 { 872 int err; 873 874 err = register_pernet_subsys(&icmpv6_sk_ops); 875 if (err < 0) 876 return err; 877 878 err = -EAGAIN; 879 if (inet6_add_protocol(&icmpv6_protocol, IPPROTO_ICMPV6) < 0) 880 goto fail; 881 return 0; 882 883 fail: 884 pr_err("Failed to register ICMP6 protocol\n"); 885 unregister_pernet_subsys(&icmpv6_sk_ops); 886 return err; 887 } 888 889 void icmpv6_cleanup(void) 890 { 891 unregister_pernet_subsys(&icmpv6_sk_ops); 892 inet6_del_protocol(&icmpv6_protocol, IPPROTO_ICMPV6); 893 } 894 895 896 static const struct icmp6_err { 897 int err; 898 int fatal; 899 } tab_unreach[] = { 900 { /* NOROUTE */ 901 .err = ENETUNREACH, 902 .fatal = 0, 903 }, 904 { /* ADM_PROHIBITED */ 905 .err = EACCES, 906 .fatal = 1, 907 }, 908 { /* Was NOT_NEIGHBOUR, now reserved */ 909 .err = EHOSTUNREACH, 910 .fatal = 0, 911 }, 912 { /* ADDR_UNREACH */ 913 .err = EHOSTUNREACH, 914 .fatal = 0, 915 }, 916 { /* PORT_UNREACH */ 917 .err = ECONNREFUSED, 918 .fatal = 1, 919 }, 920 }; 921 922 int icmpv6_err_convert(u8 type, u8 code, int *err) 923 { 924 int fatal = 0; 925 926 *err = EPROTO; 927 928 switch (type) { 929 case ICMPV6_DEST_UNREACH: 930 fatal = 1; 931 if (code <= ICMPV6_PORT_UNREACH) { 932 *err = tab_unreach[code].err; 933 fatal = tab_unreach[code].fatal; 934 } 935 break; 936 937 case ICMPV6_PKT_TOOBIG: 938 *err = EMSGSIZE; 939 break; 940 941 case ICMPV6_PARAMPROB: 942 *err = EPROTO; 943 fatal = 1; 944 break; 945 946 case ICMPV6_TIME_EXCEED: 947 *err = EHOSTUNREACH; 948 break; 949 } 950 951 return fatal; 952 } 953 EXPORT_SYMBOL(icmpv6_err_convert); 954 955 #ifdef CONFIG_SYSCTL 956 ctl_table ipv6_icmp_table_template[] = { 957 { 958 .procname = "ratelimit", 959 .data = &init_net.ipv6.sysctl.icmpv6_time, 960 .maxlen = sizeof(int), 961 .mode = 0644, 962 .proc_handler = proc_dointvec_ms_jiffies, 963 }, 964 { }, 965 }; 966 967 struct ctl_table * __net_init ipv6_icmp_sysctl_init(struct net *net) 968 { 969 struct ctl_table *table; 970 971 table = kmemdup(ipv6_icmp_table_template, 972 sizeof(ipv6_icmp_table_template), 973 GFP_KERNEL); 974 975 if (table) 976 table[0].data = &net->ipv6.sysctl.icmpv6_time; 977 978 return table; 979 } 980 #endif 981 982