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 <linux/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 *this_cpu_ptr(net->ipv6.icmp_sk); 85 } 86 87 static int 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, skb->dev->ifindex, 0, sock_net_uid(net, NULL)); 96 else if (type == NDISC_REDIRECT) 97 ip6_redirect(skb, net, skb->dev->ifindex, 0, 98 sock_net_uid(net, NULL)); 99 100 if (!(type & ICMPV6_INFOMSG_MASK)) 101 if (icmp6->icmp6_type == ICMPV6_ECHO_REQUEST) 102 ping_err(skb, offset, ntohl(info)); 103 104 return 0; 105 } 106 107 static int icmpv6_rcv(struct sk_buff *skb); 108 109 static const struct inet6_protocol icmpv6_protocol = { 110 .handler = icmpv6_rcv, 111 .err_handler = icmpv6_err, 112 .flags = INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL, 113 }; 114 115 /* Called with BH disabled */ 116 static __inline__ struct sock *icmpv6_xmit_lock(struct net *net) 117 { 118 struct sock *sk; 119 120 sk = icmpv6_sk(net); 121 if (unlikely(!spin_trylock(&sk->sk_lock.slock))) { 122 /* This can happen if the output path (f.e. SIT or 123 * ip6ip6 tunnel) signals dst_link_failure() for an 124 * outgoing ICMP6 packet. 125 */ 126 return NULL; 127 } 128 return sk; 129 } 130 131 static __inline__ void icmpv6_xmit_unlock(struct sock *sk) 132 { 133 spin_unlock(&sk->sk_lock.slock); 134 } 135 136 /* 137 * Figure out, may we reply to this packet with icmp error. 138 * 139 * We do not reply, if: 140 * - it was icmp error message. 141 * - it is truncated, so that it is known, that protocol is ICMPV6 142 * (i.e. in the middle of some exthdr) 143 * 144 * --ANK (980726) 145 */ 146 147 static bool is_ineligible(const struct sk_buff *skb) 148 { 149 int ptr = (u8 *)(ipv6_hdr(skb) + 1) - skb->data; 150 int len = skb->len - ptr; 151 __u8 nexthdr = ipv6_hdr(skb)->nexthdr; 152 __be16 frag_off; 153 154 if (len < 0) 155 return true; 156 157 ptr = ipv6_skip_exthdr(skb, ptr, &nexthdr, &frag_off); 158 if (ptr < 0) 159 return false; 160 if (nexthdr == IPPROTO_ICMPV6) { 161 u8 _type, *tp; 162 tp = skb_header_pointer(skb, 163 ptr+offsetof(struct icmp6hdr, icmp6_type), 164 sizeof(_type), &_type); 165 if (!tp || !(*tp & ICMPV6_INFOMSG_MASK)) 166 return true; 167 } 168 return false; 169 } 170 171 static bool icmpv6_mask_allow(int type) 172 { 173 /* Informational messages are not limited. */ 174 if (type & ICMPV6_INFOMSG_MASK) 175 return true; 176 177 /* Do not limit pmtu discovery, it would break it. */ 178 if (type == ICMPV6_PKT_TOOBIG) 179 return true; 180 181 return false; 182 } 183 184 static bool icmpv6_global_allow(int type) 185 { 186 if (icmpv6_mask_allow(type)) 187 return true; 188 189 if (icmp_global_allow()) 190 return true; 191 192 return false; 193 } 194 195 /* 196 * Check the ICMP output rate limit 197 */ 198 static bool icmpv6_xrlim_allow(struct sock *sk, u8 type, 199 struct flowi6 *fl6) 200 { 201 struct net *net = sock_net(sk); 202 struct dst_entry *dst; 203 bool res = false; 204 205 if (icmpv6_mask_allow(type)) 206 return true; 207 208 /* 209 * Look up the output route. 210 * XXX: perhaps the expire for routing entries cloned by 211 * this lookup should be more aggressive (not longer than timeout). 212 */ 213 dst = ip6_route_output(net, sk, fl6); 214 if (dst->error) { 215 IP6_INC_STATS(net, ip6_dst_idev(dst), 216 IPSTATS_MIB_OUTNOROUTES); 217 } else if (dst->dev && (dst->dev->flags&IFF_LOOPBACK)) { 218 res = true; 219 } else { 220 struct rt6_info *rt = (struct rt6_info *)dst; 221 int tmo = net->ipv6.sysctl.icmpv6_time; 222 struct inet_peer *peer; 223 224 /* Give more bandwidth to wider prefixes. */ 225 if (rt->rt6i_dst.plen < 128) 226 tmo >>= ((128 - rt->rt6i_dst.plen)>>5); 227 228 peer = inet_getpeer_v6(net->ipv6.peers, &fl6->daddr, 1); 229 res = inet_peer_xrlim_allow(peer, tmo); 230 if (peer) 231 inet_putpeer(peer); 232 } 233 dst_release(dst); 234 return res; 235 } 236 237 /* 238 * an inline helper for the "simple" if statement below 239 * checks if parameter problem report is caused by an 240 * unrecognized IPv6 option that has the Option Type 241 * highest-order two bits set to 10 242 */ 243 244 static bool opt_unrec(struct sk_buff *skb, __u32 offset) 245 { 246 u8 _optval, *op; 247 248 offset += skb_network_offset(skb); 249 op = skb_header_pointer(skb, offset, sizeof(_optval), &_optval); 250 if (!op) 251 return true; 252 return (*op & 0xC0) == 0x80; 253 } 254 255 void icmpv6_push_pending_frames(struct sock *sk, struct flowi6 *fl6, 256 struct icmp6hdr *thdr, int len) 257 { 258 struct sk_buff *skb; 259 struct icmp6hdr *icmp6h; 260 261 skb = skb_peek(&sk->sk_write_queue); 262 if (!skb) 263 return; 264 265 icmp6h = icmp6_hdr(skb); 266 memcpy(icmp6h, thdr, sizeof(struct icmp6hdr)); 267 icmp6h->icmp6_cksum = 0; 268 269 if (skb_queue_len(&sk->sk_write_queue) == 1) { 270 skb->csum = csum_partial(icmp6h, 271 sizeof(struct icmp6hdr), skb->csum); 272 icmp6h->icmp6_cksum = csum_ipv6_magic(&fl6->saddr, 273 &fl6->daddr, 274 len, fl6->flowi6_proto, 275 skb->csum); 276 } else { 277 __wsum tmp_csum = 0; 278 279 skb_queue_walk(&sk->sk_write_queue, skb) { 280 tmp_csum = csum_add(tmp_csum, skb->csum); 281 } 282 283 tmp_csum = csum_partial(icmp6h, 284 sizeof(struct icmp6hdr), tmp_csum); 285 icmp6h->icmp6_cksum = csum_ipv6_magic(&fl6->saddr, 286 &fl6->daddr, 287 len, fl6->flowi6_proto, 288 tmp_csum); 289 } 290 ip6_push_pending_frames(sk); 291 } 292 293 struct icmpv6_msg { 294 struct sk_buff *skb; 295 int offset; 296 uint8_t type; 297 }; 298 299 static int icmpv6_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb) 300 { 301 struct icmpv6_msg *msg = (struct icmpv6_msg *) from; 302 struct sk_buff *org_skb = msg->skb; 303 __wsum csum = 0; 304 305 csum = skb_copy_and_csum_bits(org_skb, msg->offset + offset, 306 to, len, csum); 307 skb->csum = csum_block_add(skb->csum, csum, odd); 308 if (!(msg->type & ICMPV6_INFOMSG_MASK)) 309 nf_ct_attach(skb, org_skb); 310 return 0; 311 } 312 313 #if IS_ENABLED(CONFIG_IPV6_MIP6) 314 static void mip6_addr_swap(struct sk_buff *skb) 315 { 316 struct ipv6hdr *iph = ipv6_hdr(skb); 317 struct inet6_skb_parm *opt = IP6CB(skb); 318 struct ipv6_destopt_hao *hao; 319 struct in6_addr tmp; 320 int off; 321 322 if (opt->dsthao) { 323 off = ipv6_find_tlv(skb, opt->dsthao, IPV6_TLV_HAO); 324 if (likely(off >= 0)) { 325 hao = (struct ipv6_destopt_hao *) 326 (skb_network_header(skb) + off); 327 tmp = iph->saddr; 328 iph->saddr = hao->addr; 329 hao->addr = tmp; 330 } 331 } 332 } 333 #else 334 static inline void mip6_addr_swap(struct sk_buff *skb) {} 335 #endif 336 337 static struct dst_entry *icmpv6_route_lookup(struct net *net, 338 struct sk_buff *skb, 339 struct sock *sk, 340 struct flowi6 *fl6) 341 { 342 struct dst_entry *dst, *dst2; 343 struct flowi6 fl2; 344 int err; 345 346 err = ip6_dst_lookup(net, sk, &dst, fl6); 347 if (err) 348 return ERR_PTR(err); 349 350 /* 351 * We won't send icmp if the destination is known 352 * anycast. 353 */ 354 if (ipv6_anycast_destination(dst, &fl6->daddr)) { 355 net_dbg_ratelimited("icmp6_send: acast source\n"); 356 dst_release(dst); 357 return ERR_PTR(-EINVAL); 358 } 359 360 /* No need to clone since we're just using its address. */ 361 dst2 = dst; 362 363 dst = xfrm_lookup(net, dst, flowi6_to_flowi(fl6), sk, 0); 364 if (!IS_ERR(dst)) { 365 if (dst != dst2) 366 return dst; 367 } else { 368 if (PTR_ERR(dst) == -EPERM) 369 dst = NULL; 370 else 371 return dst; 372 } 373 374 err = xfrm_decode_session_reverse(skb, flowi6_to_flowi(&fl2), AF_INET6); 375 if (err) 376 goto relookup_failed; 377 378 err = ip6_dst_lookup(net, sk, &dst2, &fl2); 379 if (err) 380 goto relookup_failed; 381 382 dst2 = xfrm_lookup(net, dst2, flowi6_to_flowi(&fl2), sk, XFRM_LOOKUP_ICMP); 383 if (!IS_ERR(dst2)) { 384 dst_release(dst); 385 dst = dst2; 386 } else { 387 err = PTR_ERR(dst2); 388 if (err == -EPERM) { 389 dst_release(dst); 390 return dst2; 391 } else 392 goto relookup_failed; 393 } 394 395 relookup_failed: 396 if (dst) 397 return dst; 398 return ERR_PTR(err); 399 } 400 401 static int icmp6_iif(const struct sk_buff *skb) 402 { 403 int iif = skb->dev->ifindex; 404 405 /* for local traffic to local address, skb dev is the loopback 406 * device. Check if there is a dst attached to the skb and if so 407 * get the real device index. Same is needed for replies to a link 408 * local address on a device enslaved to an L3 master device 409 */ 410 if (unlikely(iif == LOOPBACK_IFINDEX || netif_is_l3_master(skb->dev))) { 411 const struct rt6_info *rt6 = skb_rt6_info(skb); 412 413 if (rt6) 414 iif = rt6->rt6i_idev->dev->ifindex; 415 } 416 417 return iif; 418 } 419 420 /* 421 * Send an ICMP message in response to a packet in error 422 */ 423 static void icmp6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info, 424 const struct in6_addr *force_saddr) 425 { 426 struct inet6_dev *idev = NULL; 427 struct ipv6hdr *hdr = ipv6_hdr(skb); 428 struct sock *sk; 429 struct net *net; 430 struct ipv6_pinfo *np; 431 const struct in6_addr *saddr = NULL; 432 struct dst_entry *dst; 433 struct icmp6hdr tmp_hdr; 434 struct flowi6 fl6; 435 struct icmpv6_msg msg; 436 struct ipcm6_cookie ipc6; 437 int iif = 0; 438 int addr_type = 0; 439 int len; 440 u32 mark; 441 442 if ((u8 *)hdr < skb->head || 443 (skb_network_header(skb) + sizeof(*hdr)) > skb_tail_pointer(skb)) 444 return; 445 446 if (!skb->dev) 447 return; 448 net = dev_net(skb->dev); 449 mark = IP6_REPLY_MARK(net, skb->mark); 450 /* 451 * Make sure we respect the rules 452 * i.e. RFC 1885 2.4(e) 453 * Rule (e.1) is enforced by not using icmp6_send 454 * in any code that processes icmp errors. 455 */ 456 addr_type = ipv6_addr_type(&hdr->daddr); 457 458 if (ipv6_chk_addr(net, &hdr->daddr, skb->dev, 0) || 459 ipv6_chk_acast_addr_src(net, skb->dev, &hdr->daddr)) 460 saddr = &hdr->daddr; 461 462 /* 463 * Dest addr check 464 */ 465 466 if (addr_type & IPV6_ADDR_MULTICAST || skb->pkt_type != PACKET_HOST) { 467 if (type != ICMPV6_PKT_TOOBIG && 468 !(type == ICMPV6_PARAMPROB && 469 code == ICMPV6_UNK_OPTION && 470 (opt_unrec(skb, info)))) 471 return; 472 473 saddr = NULL; 474 } 475 476 addr_type = ipv6_addr_type(&hdr->saddr); 477 478 /* 479 * Source addr check 480 */ 481 482 if (__ipv6_addr_needs_scope_id(addr_type)) { 483 iif = icmp6_iif(skb); 484 } else { 485 dst = skb_dst(skb); 486 iif = l3mdev_master_ifindex(dst ? dst->dev : skb->dev); 487 } 488 489 /* 490 * Must not send error if the source does not uniquely 491 * identify a single node (RFC2463 Section 2.4). 492 * We check unspecified / multicast addresses here, 493 * and anycast addresses will be checked later. 494 */ 495 if ((addr_type == IPV6_ADDR_ANY) || (addr_type & IPV6_ADDR_MULTICAST)) { 496 net_dbg_ratelimited("icmp6_send: addr_any/mcast source [%pI6c > %pI6c]\n", 497 &hdr->saddr, &hdr->daddr); 498 return; 499 } 500 501 /* 502 * Never answer to a ICMP packet. 503 */ 504 if (is_ineligible(skb)) { 505 net_dbg_ratelimited("icmp6_send: no reply to icmp error [%pI6c > %pI6c]\n", 506 &hdr->saddr, &hdr->daddr); 507 return; 508 } 509 510 /* Needed by both icmp_global_allow and icmpv6_xmit_lock */ 511 local_bh_disable(); 512 513 /* Check global sysctl_icmp_msgs_per_sec ratelimit */ 514 if (!(skb->dev->flags&IFF_LOOPBACK) && !icmpv6_global_allow(type)) 515 goto out_bh_enable; 516 517 mip6_addr_swap(skb); 518 519 memset(&fl6, 0, sizeof(fl6)); 520 fl6.flowi6_proto = IPPROTO_ICMPV6; 521 fl6.daddr = hdr->saddr; 522 if (force_saddr) 523 saddr = force_saddr; 524 if (saddr) 525 fl6.saddr = *saddr; 526 fl6.flowi6_mark = mark; 527 fl6.flowi6_oif = iif; 528 fl6.fl6_icmp_type = type; 529 fl6.fl6_icmp_code = code; 530 fl6.flowi6_uid = sock_net_uid(net, NULL); 531 fl6.mp_hash = rt6_multipath_hash(net, &fl6, skb, NULL); 532 security_skb_classify_flow(skb, flowi6_to_flowi(&fl6)); 533 534 sk = icmpv6_xmit_lock(net); 535 if (!sk) 536 goto out_bh_enable; 537 538 sk->sk_mark = mark; 539 np = inet6_sk(sk); 540 541 if (!icmpv6_xrlim_allow(sk, type, &fl6)) 542 goto out; 543 544 tmp_hdr.icmp6_type = type; 545 tmp_hdr.icmp6_code = code; 546 tmp_hdr.icmp6_cksum = 0; 547 tmp_hdr.icmp6_pointer = htonl(info); 548 549 if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr)) 550 fl6.flowi6_oif = np->mcast_oif; 551 else if (!fl6.flowi6_oif) 552 fl6.flowi6_oif = np->ucast_oif; 553 554 ipcm6_init_sk(&ipc6, np); 555 fl6.flowlabel = ip6_make_flowinfo(ipc6.tclass, fl6.flowlabel); 556 557 dst = icmpv6_route_lookup(net, skb, sk, &fl6); 558 if (IS_ERR(dst)) 559 goto out; 560 561 ipc6.hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst); 562 563 msg.skb = skb; 564 msg.offset = skb_network_offset(skb); 565 msg.type = type; 566 567 len = skb->len - msg.offset; 568 len = min_t(unsigned int, len, IPV6_MIN_MTU - sizeof(struct ipv6hdr) - sizeof(struct icmp6hdr)); 569 if (len < 0) { 570 net_dbg_ratelimited("icmp: len problem [%pI6c > %pI6c]\n", 571 &hdr->saddr, &hdr->daddr); 572 goto out_dst_release; 573 } 574 575 rcu_read_lock(); 576 idev = __in6_dev_get(skb->dev); 577 578 if (ip6_append_data(sk, icmpv6_getfrag, &msg, 579 len + sizeof(struct icmp6hdr), 580 sizeof(struct icmp6hdr), 581 &ipc6, &fl6, (struct rt6_info *)dst, 582 MSG_DONTWAIT)) { 583 ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTERRORS); 584 ip6_flush_pending_frames(sk); 585 } else { 586 icmpv6_push_pending_frames(sk, &fl6, &tmp_hdr, 587 len + sizeof(struct icmp6hdr)); 588 } 589 rcu_read_unlock(); 590 out_dst_release: 591 dst_release(dst); 592 out: 593 icmpv6_xmit_unlock(sk); 594 out_bh_enable: 595 local_bh_enable(); 596 } 597 598 /* Slightly more convenient version of icmp6_send. 599 */ 600 void icmpv6_param_prob(struct sk_buff *skb, u8 code, int pos) 601 { 602 icmp6_send(skb, ICMPV6_PARAMPROB, code, pos, NULL); 603 kfree_skb(skb); 604 } 605 606 /* Generate icmpv6 with type/code ICMPV6_DEST_UNREACH/ICMPV6_ADDR_UNREACH 607 * if sufficient data bytes are available 608 * @nhs is the size of the tunnel header(s) : 609 * Either an IPv4 header for SIT encap 610 * an IPv4 header + GRE header for GRE encap 611 */ 612 int ip6_err_gen_icmpv6_unreach(struct sk_buff *skb, int nhs, int type, 613 unsigned int data_len) 614 { 615 struct in6_addr temp_saddr; 616 struct rt6_info *rt; 617 struct sk_buff *skb2; 618 u32 info = 0; 619 620 if (!pskb_may_pull(skb, nhs + sizeof(struct ipv6hdr) + 8)) 621 return 1; 622 623 /* RFC 4884 (partial) support for ICMP extensions */ 624 if (data_len < 128 || (data_len & 7) || skb->len < data_len) 625 data_len = 0; 626 627 skb2 = data_len ? skb_copy(skb, GFP_ATOMIC) : skb_clone(skb, GFP_ATOMIC); 628 629 if (!skb2) 630 return 1; 631 632 skb_dst_drop(skb2); 633 skb_pull(skb2, nhs); 634 skb_reset_network_header(skb2); 635 636 rt = rt6_lookup(dev_net(skb->dev), &ipv6_hdr(skb2)->saddr, NULL, 0, 637 skb, 0); 638 639 if (rt && rt->dst.dev) 640 skb2->dev = rt->dst.dev; 641 642 ipv6_addr_set_v4mapped(ip_hdr(skb)->saddr, &temp_saddr); 643 644 if (data_len) { 645 /* RFC 4884 (partial) support : 646 * insert 0 padding at the end, before the extensions 647 */ 648 __skb_push(skb2, nhs); 649 skb_reset_network_header(skb2); 650 memmove(skb2->data, skb2->data + nhs, data_len - nhs); 651 memset(skb2->data + data_len - nhs, 0, nhs); 652 /* RFC 4884 4.5 : Length is measured in 64-bit words, 653 * and stored in reserved[0] 654 */ 655 info = (data_len/8) << 24; 656 } 657 if (type == ICMP_TIME_EXCEEDED) 658 icmp6_send(skb2, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT, 659 info, &temp_saddr); 660 else 661 icmp6_send(skb2, ICMPV6_DEST_UNREACH, ICMPV6_ADDR_UNREACH, 662 info, &temp_saddr); 663 if (rt) 664 ip6_rt_put(rt); 665 666 kfree_skb(skb2); 667 668 return 0; 669 } 670 EXPORT_SYMBOL(ip6_err_gen_icmpv6_unreach); 671 672 static void icmpv6_echo_reply(struct sk_buff *skb) 673 { 674 struct net *net = dev_net(skb->dev); 675 struct sock *sk; 676 struct inet6_dev *idev; 677 struct ipv6_pinfo *np; 678 const struct in6_addr *saddr = NULL; 679 struct icmp6hdr *icmph = icmp6_hdr(skb); 680 struct icmp6hdr tmp_hdr; 681 struct flowi6 fl6; 682 struct icmpv6_msg msg; 683 struct dst_entry *dst; 684 struct ipcm6_cookie ipc6; 685 u32 mark = IP6_REPLY_MARK(net, skb->mark); 686 687 saddr = &ipv6_hdr(skb)->daddr; 688 689 if (!ipv6_unicast_destination(skb) && 690 !(net->ipv6.sysctl.anycast_src_echo_reply && 691 ipv6_anycast_destination(skb_dst(skb), saddr))) 692 saddr = NULL; 693 694 memcpy(&tmp_hdr, icmph, sizeof(tmp_hdr)); 695 tmp_hdr.icmp6_type = ICMPV6_ECHO_REPLY; 696 697 memset(&fl6, 0, sizeof(fl6)); 698 fl6.flowi6_proto = IPPROTO_ICMPV6; 699 fl6.daddr = ipv6_hdr(skb)->saddr; 700 if (saddr) 701 fl6.saddr = *saddr; 702 fl6.flowi6_oif = icmp6_iif(skb); 703 fl6.fl6_icmp_type = ICMPV6_ECHO_REPLY; 704 fl6.flowi6_mark = mark; 705 fl6.flowi6_uid = sock_net_uid(net, NULL); 706 security_skb_classify_flow(skb, flowi6_to_flowi(&fl6)); 707 708 local_bh_disable(); 709 sk = icmpv6_xmit_lock(net); 710 if (!sk) 711 goto out_bh_enable; 712 sk->sk_mark = mark; 713 np = inet6_sk(sk); 714 715 if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr)) 716 fl6.flowi6_oif = np->mcast_oif; 717 else if (!fl6.flowi6_oif) 718 fl6.flowi6_oif = np->ucast_oif; 719 720 if (ip6_dst_lookup(net, sk, &dst, &fl6)) 721 goto out; 722 dst = xfrm_lookup(net, dst, flowi6_to_flowi(&fl6), sk, 0); 723 if (IS_ERR(dst)) 724 goto out; 725 726 idev = __in6_dev_get(skb->dev); 727 728 msg.skb = skb; 729 msg.offset = 0; 730 msg.type = ICMPV6_ECHO_REPLY; 731 732 ipcm6_init_sk(&ipc6, np); 733 ipc6.hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst); 734 ipc6.tclass = ipv6_get_dsfield(ipv6_hdr(skb)); 735 736 if (ip6_append_data(sk, icmpv6_getfrag, &msg, 737 skb->len + sizeof(struct icmp6hdr), 738 sizeof(struct icmp6hdr), &ipc6, &fl6, 739 (struct rt6_info *)dst, MSG_DONTWAIT)) { 740 __ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTERRORS); 741 ip6_flush_pending_frames(sk); 742 } else { 743 icmpv6_push_pending_frames(sk, &fl6, &tmp_hdr, 744 skb->len + sizeof(struct icmp6hdr)); 745 } 746 dst_release(dst); 747 out: 748 icmpv6_xmit_unlock(sk); 749 out_bh_enable: 750 local_bh_enable(); 751 } 752 753 void icmpv6_notify(struct sk_buff *skb, u8 type, u8 code, __be32 info) 754 { 755 const struct inet6_protocol *ipprot; 756 int inner_offset; 757 __be16 frag_off; 758 u8 nexthdr; 759 struct net *net = dev_net(skb->dev); 760 761 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr))) 762 goto out; 763 764 nexthdr = ((struct ipv6hdr *)skb->data)->nexthdr; 765 if (ipv6_ext_hdr(nexthdr)) { 766 /* now skip over extension headers */ 767 inner_offset = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), 768 &nexthdr, &frag_off); 769 if (inner_offset < 0) 770 goto out; 771 } else { 772 inner_offset = sizeof(struct ipv6hdr); 773 } 774 775 /* Checkin header including 8 bytes of inner protocol header. */ 776 if (!pskb_may_pull(skb, inner_offset+8)) 777 goto out; 778 779 /* BUGGG_FUTURE: we should try to parse exthdrs in this packet. 780 Without this we will not able f.e. to make source routed 781 pmtu discovery. 782 Corresponding argument (opt) to notifiers is already added. 783 --ANK (980726) 784 */ 785 786 ipprot = rcu_dereference(inet6_protos[nexthdr]); 787 if (ipprot && ipprot->err_handler) 788 ipprot->err_handler(skb, NULL, type, code, inner_offset, info); 789 790 raw6_icmp_error(skb, nexthdr, type, code, inner_offset, info); 791 return; 792 793 out: 794 __ICMP6_INC_STATS(net, __in6_dev_get(skb->dev), ICMP6_MIB_INERRORS); 795 } 796 797 /* 798 * Handle icmp messages 799 */ 800 801 static int icmpv6_rcv(struct sk_buff *skb) 802 { 803 struct net *net = dev_net(skb->dev); 804 struct net_device *dev = skb->dev; 805 struct inet6_dev *idev = __in6_dev_get(dev); 806 const struct in6_addr *saddr, *daddr; 807 struct icmp6hdr *hdr; 808 u8 type; 809 bool success = false; 810 811 if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) { 812 struct sec_path *sp = skb_sec_path(skb); 813 int nh; 814 815 if (!(sp && sp->xvec[sp->len - 1]->props.flags & 816 XFRM_STATE_ICMP)) 817 goto drop_no_count; 818 819 if (!pskb_may_pull(skb, sizeof(*hdr) + sizeof(struct ipv6hdr))) 820 goto drop_no_count; 821 822 nh = skb_network_offset(skb); 823 skb_set_network_header(skb, sizeof(*hdr)); 824 825 if (!xfrm6_policy_check_reverse(NULL, XFRM_POLICY_IN, skb)) 826 goto drop_no_count; 827 828 skb_set_network_header(skb, nh); 829 } 830 831 __ICMP6_INC_STATS(dev_net(dev), idev, ICMP6_MIB_INMSGS); 832 833 saddr = &ipv6_hdr(skb)->saddr; 834 daddr = &ipv6_hdr(skb)->daddr; 835 836 if (skb_checksum_validate(skb, IPPROTO_ICMPV6, ip6_compute_pseudo)) { 837 net_dbg_ratelimited("ICMPv6 checksum failed [%pI6c > %pI6c]\n", 838 saddr, daddr); 839 goto csum_error; 840 } 841 842 if (!pskb_pull(skb, sizeof(*hdr))) 843 goto discard_it; 844 845 hdr = icmp6_hdr(skb); 846 847 type = hdr->icmp6_type; 848 849 ICMP6MSGIN_INC_STATS(dev_net(dev), idev, type); 850 851 switch (type) { 852 case ICMPV6_ECHO_REQUEST: 853 if (!net->ipv6.sysctl.icmpv6_echo_ignore_all) 854 icmpv6_echo_reply(skb); 855 break; 856 857 case ICMPV6_ECHO_REPLY: 858 success = ping_rcv(skb); 859 break; 860 861 case ICMPV6_PKT_TOOBIG: 862 /* BUGGG_FUTURE: if packet contains rthdr, we cannot update 863 standard destination cache. Seems, only "advanced" 864 destination cache will allow to solve this problem 865 --ANK (980726) 866 */ 867 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr))) 868 goto discard_it; 869 hdr = icmp6_hdr(skb); 870 871 /* to notify */ 872 /* fall through */ 873 case ICMPV6_DEST_UNREACH: 874 case ICMPV6_TIME_EXCEED: 875 case ICMPV6_PARAMPROB: 876 icmpv6_notify(skb, type, hdr->icmp6_code, hdr->icmp6_mtu); 877 break; 878 879 case NDISC_ROUTER_SOLICITATION: 880 case NDISC_ROUTER_ADVERTISEMENT: 881 case NDISC_NEIGHBOUR_SOLICITATION: 882 case NDISC_NEIGHBOUR_ADVERTISEMENT: 883 case NDISC_REDIRECT: 884 ndisc_rcv(skb); 885 break; 886 887 case ICMPV6_MGM_QUERY: 888 igmp6_event_query(skb); 889 break; 890 891 case ICMPV6_MGM_REPORT: 892 igmp6_event_report(skb); 893 break; 894 895 case ICMPV6_MGM_REDUCTION: 896 case ICMPV6_NI_QUERY: 897 case ICMPV6_NI_REPLY: 898 case ICMPV6_MLD2_REPORT: 899 case ICMPV6_DHAAD_REQUEST: 900 case ICMPV6_DHAAD_REPLY: 901 case ICMPV6_MOBILE_PREFIX_SOL: 902 case ICMPV6_MOBILE_PREFIX_ADV: 903 break; 904 905 default: 906 /* informational */ 907 if (type & ICMPV6_INFOMSG_MASK) 908 break; 909 910 net_dbg_ratelimited("icmpv6: msg of unknown type [%pI6c > %pI6c]\n", 911 saddr, daddr); 912 913 /* 914 * error of unknown type. 915 * must pass to upper level 916 */ 917 918 icmpv6_notify(skb, type, hdr->icmp6_code, hdr->icmp6_mtu); 919 } 920 921 /* until the v6 path can be better sorted assume failure and 922 * preserve the status quo behaviour for the rest of the paths to here 923 */ 924 if (success) 925 consume_skb(skb); 926 else 927 kfree_skb(skb); 928 929 return 0; 930 931 csum_error: 932 __ICMP6_INC_STATS(dev_net(dev), idev, ICMP6_MIB_CSUMERRORS); 933 discard_it: 934 __ICMP6_INC_STATS(dev_net(dev), idev, ICMP6_MIB_INERRORS); 935 drop_no_count: 936 kfree_skb(skb); 937 return 0; 938 } 939 940 void icmpv6_flow_init(struct sock *sk, struct flowi6 *fl6, 941 u8 type, 942 const struct in6_addr *saddr, 943 const struct in6_addr *daddr, 944 int oif) 945 { 946 memset(fl6, 0, sizeof(*fl6)); 947 fl6->saddr = *saddr; 948 fl6->daddr = *daddr; 949 fl6->flowi6_proto = IPPROTO_ICMPV6; 950 fl6->fl6_icmp_type = type; 951 fl6->fl6_icmp_code = 0; 952 fl6->flowi6_oif = oif; 953 security_sk_classify_flow(sk, flowi6_to_flowi(fl6)); 954 } 955 956 static void __net_exit icmpv6_sk_exit(struct net *net) 957 { 958 int i; 959 960 for_each_possible_cpu(i) 961 inet_ctl_sock_destroy(*per_cpu_ptr(net->ipv6.icmp_sk, i)); 962 free_percpu(net->ipv6.icmp_sk); 963 } 964 965 static int __net_init icmpv6_sk_init(struct net *net) 966 { 967 struct sock *sk; 968 int err, i; 969 970 net->ipv6.icmp_sk = alloc_percpu(struct sock *); 971 if (!net->ipv6.icmp_sk) 972 return -ENOMEM; 973 974 for_each_possible_cpu(i) { 975 err = inet_ctl_sock_create(&sk, PF_INET6, 976 SOCK_RAW, IPPROTO_ICMPV6, net); 977 if (err < 0) { 978 pr_err("Failed to initialize the ICMP6 control socket (err %d)\n", 979 err); 980 goto fail; 981 } 982 983 *per_cpu_ptr(net->ipv6.icmp_sk, i) = sk; 984 985 /* Enough space for 2 64K ICMP packets, including 986 * sk_buff struct overhead. 987 */ 988 sk->sk_sndbuf = 2 * SKB_TRUESIZE(64 * 1024); 989 } 990 return 0; 991 992 fail: 993 icmpv6_sk_exit(net); 994 return err; 995 } 996 997 static struct pernet_operations icmpv6_sk_ops = { 998 .init = icmpv6_sk_init, 999 .exit = icmpv6_sk_exit, 1000 }; 1001 1002 int __init icmpv6_init(void) 1003 { 1004 int err; 1005 1006 err = register_pernet_subsys(&icmpv6_sk_ops); 1007 if (err < 0) 1008 return err; 1009 1010 err = -EAGAIN; 1011 if (inet6_add_protocol(&icmpv6_protocol, IPPROTO_ICMPV6) < 0) 1012 goto fail; 1013 1014 err = inet6_register_icmp_sender(icmp6_send); 1015 if (err) 1016 goto sender_reg_err; 1017 return 0; 1018 1019 sender_reg_err: 1020 inet6_del_protocol(&icmpv6_protocol, IPPROTO_ICMPV6); 1021 fail: 1022 pr_err("Failed to register ICMP6 protocol\n"); 1023 unregister_pernet_subsys(&icmpv6_sk_ops); 1024 return err; 1025 } 1026 1027 void icmpv6_cleanup(void) 1028 { 1029 inet6_unregister_icmp_sender(icmp6_send); 1030 unregister_pernet_subsys(&icmpv6_sk_ops); 1031 inet6_del_protocol(&icmpv6_protocol, IPPROTO_ICMPV6); 1032 } 1033 1034 1035 static const struct icmp6_err { 1036 int err; 1037 int fatal; 1038 } tab_unreach[] = { 1039 { /* NOROUTE */ 1040 .err = ENETUNREACH, 1041 .fatal = 0, 1042 }, 1043 { /* ADM_PROHIBITED */ 1044 .err = EACCES, 1045 .fatal = 1, 1046 }, 1047 { /* Was NOT_NEIGHBOUR, now reserved */ 1048 .err = EHOSTUNREACH, 1049 .fatal = 0, 1050 }, 1051 { /* ADDR_UNREACH */ 1052 .err = EHOSTUNREACH, 1053 .fatal = 0, 1054 }, 1055 { /* PORT_UNREACH */ 1056 .err = ECONNREFUSED, 1057 .fatal = 1, 1058 }, 1059 { /* POLICY_FAIL */ 1060 .err = EACCES, 1061 .fatal = 1, 1062 }, 1063 { /* REJECT_ROUTE */ 1064 .err = EACCES, 1065 .fatal = 1, 1066 }, 1067 }; 1068 1069 int icmpv6_err_convert(u8 type, u8 code, int *err) 1070 { 1071 int fatal = 0; 1072 1073 *err = EPROTO; 1074 1075 switch (type) { 1076 case ICMPV6_DEST_UNREACH: 1077 fatal = 1; 1078 if (code < ARRAY_SIZE(tab_unreach)) { 1079 *err = tab_unreach[code].err; 1080 fatal = tab_unreach[code].fatal; 1081 } 1082 break; 1083 1084 case ICMPV6_PKT_TOOBIG: 1085 *err = EMSGSIZE; 1086 break; 1087 1088 case ICMPV6_PARAMPROB: 1089 *err = EPROTO; 1090 fatal = 1; 1091 break; 1092 1093 case ICMPV6_TIME_EXCEED: 1094 *err = EHOSTUNREACH; 1095 break; 1096 } 1097 1098 return fatal; 1099 } 1100 EXPORT_SYMBOL(icmpv6_err_convert); 1101 1102 #ifdef CONFIG_SYSCTL 1103 static struct ctl_table ipv6_icmp_table_template[] = { 1104 { 1105 .procname = "ratelimit", 1106 .data = &init_net.ipv6.sysctl.icmpv6_time, 1107 .maxlen = sizeof(int), 1108 .mode = 0644, 1109 .proc_handler = proc_dointvec_ms_jiffies, 1110 }, 1111 { 1112 .procname = "echo_ignore_all", 1113 .data = &init_net.ipv6.sysctl.icmpv6_echo_ignore_all, 1114 .maxlen = sizeof(int), 1115 .mode = 0644, 1116 .proc_handler = proc_dointvec, 1117 }, 1118 { }, 1119 }; 1120 1121 struct ctl_table * __net_init ipv6_icmp_sysctl_init(struct net *net) 1122 { 1123 struct ctl_table *table; 1124 1125 table = kmemdup(ipv6_icmp_table_template, 1126 sizeof(ipv6_icmp_table_template), 1127 GFP_KERNEL); 1128 1129 if (table) { 1130 table[0].data = &net->ipv6.sysctl.icmpv6_time; 1131 table[1].data = &net->ipv6.sysctl.icmpv6_echo_ignore_all; 1132 } 1133 return table; 1134 } 1135 #endif 1136