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 { 393 struct net *net = dev_net(skb->dev); 394 struct inet6_dev *idev = NULL; 395 struct ipv6hdr *hdr = ipv6_hdr(skb); 396 struct sock *sk; 397 struct ipv6_pinfo *np; 398 const struct in6_addr *saddr = NULL; 399 struct dst_entry *dst; 400 struct icmp6hdr tmp_hdr; 401 struct flowi6 fl6; 402 struct icmpv6_msg msg; 403 struct sockcm_cookie sockc_unused = {0}; 404 struct ipcm6_cookie ipc6; 405 int iif = 0; 406 int addr_type = 0; 407 int len; 408 int err = 0; 409 u32 mark = IP6_REPLY_MARK(net, skb->mark); 410 411 if ((u8 *)hdr < skb->head || 412 (skb_network_header(skb) + sizeof(*hdr)) > skb_tail_pointer(skb)) 413 return; 414 415 /* 416 * Make sure we respect the rules 417 * i.e. RFC 1885 2.4(e) 418 * Rule (e.1) is enforced by not using icmp6_send 419 * in any code that processes icmp errors. 420 */ 421 addr_type = ipv6_addr_type(&hdr->daddr); 422 423 if (ipv6_chk_addr(net, &hdr->daddr, skb->dev, 0) || 424 ipv6_chk_acast_addr_src(net, skb->dev, &hdr->daddr)) 425 saddr = &hdr->daddr; 426 427 /* 428 * Dest addr check 429 */ 430 431 if (addr_type & IPV6_ADDR_MULTICAST || skb->pkt_type != PACKET_HOST) { 432 if (type != ICMPV6_PKT_TOOBIG && 433 !(type == ICMPV6_PARAMPROB && 434 code == ICMPV6_UNK_OPTION && 435 (opt_unrec(skb, info)))) 436 return; 437 438 saddr = NULL; 439 } 440 441 addr_type = ipv6_addr_type(&hdr->saddr); 442 443 /* 444 * Source addr check 445 */ 446 447 if (__ipv6_addr_needs_scope_id(addr_type)) 448 iif = skb->dev->ifindex; 449 else 450 iif = l3mdev_master_ifindex(skb->dev); 451 452 /* 453 * Must not send error if the source does not uniquely 454 * identify a single node (RFC2463 Section 2.4). 455 * We check unspecified / multicast addresses here, 456 * and anycast addresses will be checked later. 457 */ 458 if ((addr_type == IPV6_ADDR_ANY) || (addr_type & IPV6_ADDR_MULTICAST)) { 459 net_dbg_ratelimited("icmp6_send: addr_any/mcast source [%pI6c > %pI6c]\n", 460 &hdr->saddr, &hdr->daddr); 461 return; 462 } 463 464 /* 465 * Never answer to a ICMP packet. 466 */ 467 if (is_ineligible(skb)) { 468 net_dbg_ratelimited("icmp6_send: no reply to icmp error [%pI6c > %pI6c]\n", 469 &hdr->saddr, &hdr->daddr); 470 return; 471 } 472 473 mip6_addr_swap(skb); 474 475 memset(&fl6, 0, sizeof(fl6)); 476 fl6.flowi6_proto = IPPROTO_ICMPV6; 477 fl6.daddr = hdr->saddr; 478 if (saddr) 479 fl6.saddr = *saddr; 480 fl6.flowi6_mark = mark; 481 fl6.flowi6_oif = iif; 482 fl6.fl6_icmp_type = type; 483 fl6.fl6_icmp_code = code; 484 security_skb_classify_flow(skb, flowi6_to_flowi(&fl6)); 485 486 sk = icmpv6_xmit_lock(net); 487 if (!sk) 488 return; 489 sk->sk_mark = mark; 490 np = inet6_sk(sk); 491 492 if (!icmpv6_xrlim_allow(sk, type, &fl6)) 493 goto out; 494 495 tmp_hdr.icmp6_type = type; 496 tmp_hdr.icmp6_code = code; 497 tmp_hdr.icmp6_cksum = 0; 498 tmp_hdr.icmp6_pointer = htonl(info); 499 500 if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr)) 501 fl6.flowi6_oif = np->mcast_oif; 502 else if (!fl6.flowi6_oif) 503 fl6.flowi6_oif = np->ucast_oif; 504 505 ipc6.tclass = np->tclass; 506 fl6.flowlabel = ip6_make_flowinfo(ipc6.tclass, fl6.flowlabel); 507 508 dst = icmpv6_route_lookup(net, skb, sk, &fl6); 509 if (IS_ERR(dst)) 510 goto out; 511 512 ipc6.hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst); 513 ipc6.dontfrag = np->dontfrag; 514 ipc6.opt = NULL; 515 516 msg.skb = skb; 517 msg.offset = skb_network_offset(skb); 518 msg.type = type; 519 520 len = skb->len - msg.offset; 521 len = min_t(unsigned int, len, IPV6_MIN_MTU - sizeof(struct ipv6hdr) - sizeof(struct icmp6hdr)); 522 if (len < 0) { 523 net_dbg_ratelimited("icmp: len problem [%pI6c > %pI6c]\n", 524 &hdr->saddr, &hdr->daddr); 525 goto out_dst_release; 526 } 527 528 rcu_read_lock(); 529 idev = __in6_dev_get(skb->dev); 530 531 err = ip6_append_data(sk, icmpv6_getfrag, &msg, 532 len + sizeof(struct icmp6hdr), 533 sizeof(struct icmp6hdr), 534 &ipc6, &fl6, (struct rt6_info *)dst, 535 MSG_DONTWAIT, &sockc_unused); 536 if (err) { 537 ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTERRORS); 538 ip6_flush_pending_frames(sk); 539 } else { 540 err = icmpv6_push_pending_frames(sk, &fl6, &tmp_hdr, 541 len + sizeof(struct icmp6hdr)); 542 } 543 rcu_read_unlock(); 544 out_dst_release: 545 dst_release(dst); 546 out: 547 icmpv6_xmit_unlock(sk); 548 } 549 550 /* Slightly more convenient version of icmp6_send. 551 */ 552 void icmpv6_param_prob(struct sk_buff *skb, u8 code, int pos) 553 { 554 icmp6_send(skb, ICMPV6_PARAMPROB, code, pos); 555 kfree_skb(skb); 556 } 557 558 static void icmpv6_echo_reply(struct sk_buff *skb) 559 { 560 struct net *net = dev_net(skb->dev); 561 struct sock *sk; 562 struct inet6_dev *idev; 563 struct ipv6_pinfo *np; 564 const struct in6_addr *saddr = NULL; 565 struct icmp6hdr *icmph = icmp6_hdr(skb); 566 struct icmp6hdr tmp_hdr; 567 struct flowi6 fl6; 568 struct icmpv6_msg msg; 569 struct dst_entry *dst; 570 struct ipcm6_cookie ipc6; 571 int err = 0; 572 u32 mark = IP6_REPLY_MARK(net, skb->mark); 573 struct sockcm_cookie sockc_unused = {0}; 574 575 saddr = &ipv6_hdr(skb)->daddr; 576 577 if (!ipv6_unicast_destination(skb) && 578 !(net->ipv6.sysctl.anycast_src_echo_reply && 579 ipv6_anycast_destination(skb_dst(skb), saddr))) 580 saddr = NULL; 581 582 memcpy(&tmp_hdr, icmph, sizeof(tmp_hdr)); 583 tmp_hdr.icmp6_type = ICMPV6_ECHO_REPLY; 584 585 memset(&fl6, 0, sizeof(fl6)); 586 fl6.flowi6_proto = IPPROTO_ICMPV6; 587 fl6.daddr = ipv6_hdr(skb)->saddr; 588 if (saddr) 589 fl6.saddr = *saddr; 590 fl6.flowi6_oif = l3mdev_fib_oif(skb->dev); 591 fl6.fl6_icmp_type = ICMPV6_ECHO_REPLY; 592 fl6.flowi6_mark = mark; 593 security_skb_classify_flow(skb, flowi6_to_flowi(&fl6)); 594 595 sk = icmpv6_xmit_lock(net); 596 if (!sk) 597 return; 598 sk->sk_mark = mark; 599 np = inet6_sk(sk); 600 601 if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr)) 602 fl6.flowi6_oif = np->mcast_oif; 603 else if (!fl6.flowi6_oif) 604 fl6.flowi6_oif = np->ucast_oif; 605 606 err = ip6_dst_lookup(net, sk, &dst, &fl6); 607 if (err) 608 goto out; 609 dst = xfrm_lookup(net, dst, flowi6_to_flowi(&fl6), sk, 0); 610 if (IS_ERR(dst)) 611 goto out; 612 613 idev = __in6_dev_get(skb->dev); 614 615 msg.skb = skb; 616 msg.offset = 0; 617 msg.type = ICMPV6_ECHO_REPLY; 618 619 ipc6.hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst); 620 ipc6.tclass = ipv6_get_dsfield(ipv6_hdr(skb)); 621 ipc6.dontfrag = np->dontfrag; 622 ipc6.opt = NULL; 623 624 err = ip6_append_data(sk, icmpv6_getfrag, &msg, skb->len + sizeof(struct icmp6hdr), 625 sizeof(struct icmp6hdr), &ipc6, &fl6, 626 (struct rt6_info *)dst, MSG_DONTWAIT, 627 &sockc_unused); 628 629 if (err) { 630 __ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTERRORS); 631 ip6_flush_pending_frames(sk); 632 } else { 633 err = icmpv6_push_pending_frames(sk, &fl6, &tmp_hdr, 634 skb->len + sizeof(struct icmp6hdr)); 635 } 636 dst_release(dst); 637 out: 638 icmpv6_xmit_unlock(sk); 639 } 640 641 void icmpv6_notify(struct sk_buff *skb, u8 type, u8 code, __be32 info) 642 { 643 const struct inet6_protocol *ipprot; 644 int inner_offset; 645 __be16 frag_off; 646 u8 nexthdr; 647 struct net *net = dev_net(skb->dev); 648 649 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr))) 650 goto out; 651 652 nexthdr = ((struct ipv6hdr *)skb->data)->nexthdr; 653 if (ipv6_ext_hdr(nexthdr)) { 654 /* now skip over extension headers */ 655 inner_offset = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), 656 &nexthdr, &frag_off); 657 if (inner_offset < 0) 658 goto out; 659 } else { 660 inner_offset = sizeof(struct ipv6hdr); 661 } 662 663 /* Checkin header including 8 bytes of inner protocol header. */ 664 if (!pskb_may_pull(skb, inner_offset+8)) 665 goto out; 666 667 /* BUGGG_FUTURE: we should try to parse exthdrs in this packet. 668 Without this we will not able f.e. to make source routed 669 pmtu discovery. 670 Corresponding argument (opt) to notifiers is already added. 671 --ANK (980726) 672 */ 673 674 ipprot = rcu_dereference(inet6_protos[nexthdr]); 675 if (ipprot && ipprot->err_handler) 676 ipprot->err_handler(skb, NULL, type, code, inner_offset, info); 677 678 raw6_icmp_error(skb, nexthdr, type, code, inner_offset, info); 679 return; 680 681 out: 682 __ICMP6_INC_STATS(net, __in6_dev_get(skb->dev), ICMP6_MIB_INERRORS); 683 } 684 685 /* 686 * Handle icmp messages 687 */ 688 689 static int icmpv6_rcv(struct sk_buff *skb) 690 { 691 struct net_device *dev = skb->dev; 692 struct inet6_dev *idev = __in6_dev_get(dev); 693 const struct in6_addr *saddr, *daddr; 694 struct icmp6hdr *hdr; 695 u8 type; 696 bool success = false; 697 698 if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) { 699 struct sec_path *sp = skb_sec_path(skb); 700 int nh; 701 702 if (!(sp && sp->xvec[sp->len - 1]->props.flags & 703 XFRM_STATE_ICMP)) 704 goto drop_no_count; 705 706 if (!pskb_may_pull(skb, sizeof(*hdr) + sizeof(struct ipv6hdr))) 707 goto drop_no_count; 708 709 nh = skb_network_offset(skb); 710 skb_set_network_header(skb, sizeof(*hdr)); 711 712 if (!xfrm6_policy_check_reverse(NULL, XFRM_POLICY_IN, skb)) 713 goto drop_no_count; 714 715 skb_set_network_header(skb, nh); 716 } 717 718 __ICMP6_INC_STATS(dev_net(dev), idev, ICMP6_MIB_INMSGS); 719 720 saddr = &ipv6_hdr(skb)->saddr; 721 daddr = &ipv6_hdr(skb)->daddr; 722 723 if (skb_checksum_validate(skb, IPPROTO_ICMPV6, ip6_compute_pseudo)) { 724 net_dbg_ratelimited("ICMPv6 checksum failed [%pI6c > %pI6c]\n", 725 saddr, daddr); 726 goto csum_error; 727 } 728 729 if (!pskb_pull(skb, sizeof(*hdr))) 730 goto discard_it; 731 732 hdr = icmp6_hdr(skb); 733 734 type = hdr->icmp6_type; 735 736 ICMP6MSGIN_INC_STATS(dev_net(dev), idev, type); 737 738 switch (type) { 739 case ICMPV6_ECHO_REQUEST: 740 icmpv6_echo_reply(skb); 741 break; 742 743 case ICMPV6_ECHO_REPLY: 744 success = ping_rcv(skb); 745 break; 746 747 case ICMPV6_PKT_TOOBIG: 748 /* BUGGG_FUTURE: if packet contains rthdr, we cannot update 749 standard destination cache. Seems, only "advanced" 750 destination cache will allow to solve this problem 751 --ANK (980726) 752 */ 753 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr))) 754 goto discard_it; 755 hdr = icmp6_hdr(skb); 756 757 /* 758 * Drop through to notify 759 */ 760 761 case ICMPV6_DEST_UNREACH: 762 case ICMPV6_TIME_EXCEED: 763 case ICMPV6_PARAMPROB: 764 icmpv6_notify(skb, type, hdr->icmp6_code, hdr->icmp6_mtu); 765 break; 766 767 case NDISC_ROUTER_SOLICITATION: 768 case NDISC_ROUTER_ADVERTISEMENT: 769 case NDISC_NEIGHBOUR_SOLICITATION: 770 case NDISC_NEIGHBOUR_ADVERTISEMENT: 771 case NDISC_REDIRECT: 772 ndisc_rcv(skb); 773 break; 774 775 case ICMPV6_MGM_QUERY: 776 igmp6_event_query(skb); 777 break; 778 779 case ICMPV6_MGM_REPORT: 780 igmp6_event_report(skb); 781 break; 782 783 case ICMPV6_MGM_REDUCTION: 784 case ICMPV6_NI_QUERY: 785 case ICMPV6_NI_REPLY: 786 case ICMPV6_MLD2_REPORT: 787 case ICMPV6_DHAAD_REQUEST: 788 case ICMPV6_DHAAD_REPLY: 789 case ICMPV6_MOBILE_PREFIX_SOL: 790 case ICMPV6_MOBILE_PREFIX_ADV: 791 break; 792 793 default: 794 /* informational */ 795 if (type & ICMPV6_INFOMSG_MASK) 796 break; 797 798 net_dbg_ratelimited("icmpv6: msg of unknown type [%pI6c > %pI6c]\n", 799 saddr, daddr); 800 801 /* 802 * error of unknown type. 803 * must pass to upper level 804 */ 805 806 icmpv6_notify(skb, type, hdr->icmp6_code, hdr->icmp6_mtu); 807 } 808 809 /* until the v6 path can be better sorted assume failure and 810 * preserve the status quo behaviour for the rest of the paths to here 811 */ 812 if (success) 813 consume_skb(skb); 814 else 815 kfree_skb(skb); 816 817 return 0; 818 819 csum_error: 820 __ICMP6_INC_STATS(dev_net(dev), idev, ICMP6_MIB_CSUMERRORS); 821 discard_it: 822 __ICMP6_INC_STATS(dev_net(dev), idev, ICMP6_MIB_INERRORS); 823 drop_no_count: 824 kfree_skb(skb); 825 return 0; 826 } 827 828 void icmpv6_flow_init(struct sock *sk, struct flowi6 *fl6, 829 u8 type, 830 const struct in6_addr *saddr, 831 const struct in6_addr *daddr, 832 int oif) 833 { 834 memset(fl6, 0, sizeof(*fl6)); 835 fl6->saddr = *saddr; 836 fl6->daddr = *daddr; 837 fl6->flowi6_proto = IPPROTO_ICMPV6; 838 fl6->fl6_icmp_type = type; 839 fl6->fl6_icmp_code = 0; 840 fl6->flowi6_oif = oif; 841 security_sk_classify_flow(sk, flowi6_to_flowi(fl6)); 842 } 843 844 static int __net_init icmpv6_sk_init(struct net *net) 845 { 846 struct sock *sk; 847 int err, i, j; 848 849 net->ipv6.icmp_sk = 850 kzalloc(nr_cpu_ids * sizeof(struct sock *), GFP_KERNEL); 851 if (!net->ipv6.icmp_sk) 852 return -ENOMEM; 853 854 for_each_possible_cpu(i) { 855 err = inet_ctl_sock_create(&sk, PF_INET6, 856 SOCK_RAW, IPPROTO_ICMPV6, net); 857 if (err < 0) { 858 pr_err("Failed to initialize the ICMP6 control socket (err %d)\n", 859 err); 860 goto fail; 861 } 862 863 net->ipv6.icmp_sk[i] = sk; 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