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 if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr) && 688 net->ipv6.sysctl.icmpv6_echo_ignore_multicast) 689 return; 690 691 saddr = &ipv6_hdr(skb)->daddr; 692 693 if (!ipv6_unicast_destination(skb) && 694 !(net->ipv6.sysctl.anycast_src_echo_reply && 695 ipv6_anycast_destination(skb_dst(skb), saddr))) 696 saddr = NULL; 697 698 memcpy(&tmp_hdr, icmph, sizeof(tmp_hdr)); 699 tmp_hdr.icmp6_type = ICMPV6_ECHO_REPLY; 700 701 memset(&fl6, 0, sizeof(fl6)); 702 fl6.flowi6_proto = IPPROTO_ICMPV6; 703 fl6.daddr = ipv6_hdr(skb)->saddr; 704 if (saddr) 705 fl6.saddr = *saddr; 706 fl6.flowi6_oif = icmp6_iif(skb); 707 fl6.fl6_icmp_type = ICMPV6_ECHO_REPLY; 708 fl6.flowi6_mark = mark; 709 fl6.flowi6_uid = sock_net_uid(net, NULL); 710 security_skb_classify_flow(skb, flowi6_to_flowi(&fl6)); 711 712 local_bh_disable(); 713 sk = icmpv6_xmit_lock(net); 714 if (!sk) 715 goto out_bh_enable; 716 sk->sk_mark = mark; 717 np = inet6_sk(sk); 718 719 if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr)) 720 fl6.flowi6_oif = np->mcast_oif; 721 else if (!fl6.flowi6_oif) 722 fl6.flowi6_oif = np->ucast_oif; 723 724 if (ip6_dst_lookup(net, sk, &dst, &fl6)) 725 goto out; 726 dst = xfrm_lookup(net, dst, flowi6_to_flowi(&fl6), sk, 0); 727 if (IS_ERR(dst)) 728 goto out; 729 730 idev = __in6_dev_get(skb->dev); 731 732 msg.skb = skb; 733 msg.offset = 0; 734 msg.type = ICMPV6_ECHO_REPLY; 735 736 ipcm6_init_sk(&ipc6, np); 737 ipc6.hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst); 738 ipc6.tclass = ipv6_get_dsfield(ipv6_hdr(skb)); 739 740 if (ip6_append_data(sk, icmpv6_getfrag, &msg, 741 skb->len + sizeof(struct icmp6hdr), 742 sizeof(struct icmp6hdr), &ipc6, &fl6, 743 (struct rt6_info *)dst, MSG_DONTWAIT)) { 744 __ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTERRORS); 745 ip6_flush_pending_frames(sk); 746 } else { 747 icmpv6_push_pending_frames(sk, &fl6, &tmp_hdr, 748 skb->len + sizeof(struct icmp6hdr)); 749 } 750 dst_release(dst); 751 out: 752 icmpv6_xmit_unlock(sk); 753 out_bh_enable: 754 local_bh_enable(); 755 } 756 757 void icmpv6_notify(struct sk_buff *skb, u8 type, u8 code, __be32 info) 758 { 759 const struct inet6_protocol *ipprot; 760 int inner_offset; 761 __be16 frag_off; 762 u8 nexthdr; 763 struct net *net = dev_net(skb->dev); 764 765 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr))) 766 goto out; 767 768 nexthdr = ((struct ipv6hdr *)skb->data)->nexthdr; 769 if (ipv6_ext_hdr(nexthdr)) { 770 /* now skip over extension headers */ 771 inner_offset = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), 772 &nexthdr, &frag_off); 773 if (inner_offset < 0) 774 goto out; 775 } else { 776 inner_offset = sizeof(struct ipv6hdr); 777 } 778 779 /* Checkin header including 8 bytes of inner protocol header. */ 780 if (!pskb_may_pull(skb, inner_offset+8)) 781 goto out; 782 783 /* BUGGG_FUTURE: we should try to parse exthdrs in this packet. 784 Without this we will not able f.e. to make source routed 785 pmtu discovery. 786 Corresponding argument (opt) to notifiers is already added. 787 --ANK (980726) 788 */ 789 790 ipprot = rcu_dereference(inet6_protos[nexthdr]); 791 if (ipprot && ipprot->err_handler) 792 ipprot->err_handler(skb, NULL, type, code, inner_offset, info); 793 794 raw6_icmp_error(skb, nexthdr, type, code, inner_offset, info); 795 return; 796 797 out: 798 __ICMP6_INC_STATS(net, __in6_dev_get(skb->dev), ICMP6_MIB_INERRORS); 799 } 800 801 /* 802 * Handle icmp messages 803 */ 804 805 static int icmpv6_rcv(struct sk_buff *skb) 806 { 807 struct net *net = dev_net(skb->dev); 808 struct net_device *dev = skb->dev; 809 struct inet6_dev *idev = __in6_dev_get(dev); 810 const struct in6_addr *saddr, *daddr; 811 struct icmp6hdr *hdr; 812 u8 type; 813 bool success = false; 814 815 if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) { 816 struct sec_path *sp = skb_sec_path(skb); 817 int nh; 818 819 if (!(sp && sp->xvec[sp->len - 1]->props.flags & 820 XFRM_STATE_ICMP)) 821 goto drop_no_count; 822 823 if (!pskb_may_pull(skb, sizeof(*hdr) + sizeof(struct ipv6hdr))) 824 goto drop_no_count; 825 826 nh = skb_network_offset(skb); 827 skb_set_network_header(skb, sizeof(*hdr)); 828 829 if (!xfrm6_policy_check_reverse(NULL, XFRM_POLICY_IN, skb)) 830 goto drop_no_count; 831 832 skb_set_network_header(skb, nh); 833 } 834 835 __ICMP6_INC_STATS(dev_net(dev), idev, ICMP6_MIB_INMSGS); 836 837 saddr = &ipv6_hdr(skb)->saddr; 838 daddr = &ipv6_hdr(skb)->daddr; 839 840 if (skb_checksum_validate(skb, IPPROTO_ICMPV6, ip6_compute_pseudo)) { 841 net_dbg_ratelimited("ICMPv6 checksum failed [%pI6c > %pI6c]\n", 842 saddr, daddr); 843 goto csum_error; 844 } 845 846 if (!pskb_pull(skb, sizeof(*hdr))) 847 goto discard_it; 848 849 hdr = icmp6_hdr(skb); 850 851 type = hdr->icmp6_type; 852 853 ICMP6MSGIN_INC_STATS(dev_net(dev), idev, type); 854 855 switch (type) { 856 case ICMPV6_ECHO_REQUEST: 857 if (!net->ipv6.sysctl.icmpv6_echo_ignore_all) 858 icmpv6_echo_reply(skb); 859 break; 860 861 case ICMPV6_ECHO_REPLY: 862 success = ping_rcv(skb); 863 break; 864 865 case ICMPV6_PKT_TOOBIG: 866 /* BUGGG_FUTURE: if packet contains rthdr, we cannot update 867 standard destination cache. Seems, only "advanced" 868 destination cache will allow to solve this problem 869 --ANK (980726) 870 */ 871 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr))) 872 goto discard_it; 873 hdr = icmp6_hdr(skb); 874 875 /* to notify */ 876 /* fall through */ 877 case ICMPV6_DEST_UNREACH: 878 case ICMPV6_TIME_EXCEED: 879 case ICMPV6_PARAMPROB: 880 icmpv6_notify(skb, type, hdr->icmp6_code, hdr->icmp6_mtu); 881 break; 882 883 case NDISC_ROUTER_SOLICITATION: 884 case NDISC_ROUTER_ADVERTISEMENT: 885 case NDISC_NEIGHBOUR_SOLICITATION: 886 case NDISC_NEIGHBOUR_ADVERTISEMENT: 887 case NDISC_REDIRECT: 888 ndisc_rcv(skb); 889 break; 890 891 case ICMPV6_MGM_QUERY: 892 igmp6_event_query(skb); 893 break; 894 895 case ICMPV6_MGM_REPORT: 896 igmp6_event_report(skb); 897 break; 898 899 case ICMPV6_MGM_REDUCTION: 900 case ICMPV6_NI_QUERY: 901 case ICMPV6_NI_REPLY: 902 case ICMPV6_MLD2_REPORT: 903 case ICMPV6_DHAAD_REQUEST: 904 case ICMPV6_DHAAD_REPLY: 905 case ICMPV6_MOBILE_PREFIX_SOL: 906 case ICMPV6_MOBILE_PREFIX_ADV: 907 break; 908 909 default: 910 /* informational */ 911 if (type & ICMPV6_INFOMSG_MASK) 912 break; 913 914 net_dbg_ratelimited("icmpv6: msg of unknown type [%pI6c > %pI6c]\n", 915 saddr, daddr); 916 917 /* 918 * error of unknown type. 919 * must pass to upper level 920 */ 921 922 icmpv6_notify(skb, type, hdr->icmp6_code, hdr->icmp6_mtu); 923 } 924 925 /* until the v6 path can be better sorted assume failure and 926 * preserve the status quo behaviour for the rest of the paths to here 927 */ 928 if (success) 929 consume_skb(skb); 930 else 931 kfree_skb(skb); 932 933 return 0; 934 935 csum_error: 936 __ICMP6_INC_STATS(dev_net(dev), idev, ICMP6_MIB_CSUMERRORS); 937 discard_it: 938 __ICMP6_INC_STATS(dev_net(dev), idev, ICMP6_MIB_INERRORS); 939 drop_no_count: 940 kfree_skb(skb); 941 return 0; 942 } 943 944 void icmpv6_flow_init(struct sock *sk, struct flowi6 *fl6, 945 u8 type, 946 const struct in6_addr *saddr, 947 const struct in6_addr *daddr, 948 int oif) 949 { 950 memset(fl6, 0, sizeof(*fl6)); 951 fl6->saddr = *saddr; 952 fl6->daddr = *daddr; 953 fl6->flowi6_proto = IPPROTO_ICMPV6; 954 fl6->fl6_icmp_type = type; 955 fl6->fl6_icmp_code = 0; 956 fl6->flowi6_oif = oif; 957 security_sk_classify_flow(sk, flowi6_to_flowi(fl6)); 958 } 959 960 static void __net_exit icmpv6_sk_exit(struct net *net) 961 { 962 int i; 963 964 for_each_possible_cpu(i) 965 inet_ctl_sock_destroy(*per_cpu_ptr(net->ipv6.icmp_sk, i)); 966 free_percpu(net->ipv6.icmp_sk); 967 } 968 969 static int __net_init icmpv6_sk_init(struct net *net) 970 { 971 struct sock *sk; 972 int err, i; 973 974 net->ipv6.icmp_sk = alloc_percpu(struct sock *); 975 if (!net->ipv6.icmp_sk) 976 return -ENOMEM; 977 978 for_each_possible_cpu(i) { 979 err = inet_ctl_sock_create(&sk, PF_INET6, 980 SOCK_RAW, IPPROTO_ICMPV6, net); 981 if (err < 0) { 982 pr_err("Failed to initialize the ICMP6 control socket (err %d)\n", 983 err); 984 goto fail; 985 } 986 987 *per_cpu_ptr(net->ipv6.icmp_sk, i) = sk; 988 989 /* Enough space for 2 64K ICMP packets, including 990 * sk_buff struct overhead. 991 */ 992 sk->sk_sndbuf = 2 * SKB_TRUESIZE(64 * 1024); 993 } 994 return 0; 995 996 fail: 997 icmpv6_sk_exit(net); 998 return err; 999 } 1000 1001 static struct pernet_operations icmpv6_sk_ops = { 1002 .init = icmpv6_sk_init, 1003 .exit = icmpv6_sk_exit, 1004 }; 1005 1006 int __init icmpv6_init(void) 1007 { 1008 int err; 1009 1010 err = register_pernet_subsys(&icmpv6_sk_ops); 1011 if (err < 0) 1012 return err; 1013 1014 err = -EAGAIN; 1015 if (inet6_add_protocol(&icmpv6_protocol, IPPROTO_ICMPV6) < 0) 1016 goto fail; 1017 1018 err = inet6_register_icmp_sender(icmp6_send); 1019 if (err) 1020 goto sender_reg_err; 1021 return 0; 1022 1023 sender_reg_err: 1024 inet6_del_protocol(&icmpv6_protocol, IPPROTO_ICMPV6); 1025 fail: 1026 pr_err("Failed to register ICMP6 protocol\n"); 1027 unregister_pernet_subsys(&icmpv6_sk_ops); 1028 return err; 1029 } 1030 1031 void icmpv6_cleanup(void) 1032 { 1033 inet6_unregister_icmp_sender(icmp6_send); 1034 unregister_pernet_subsys(&icmpv6_sk_ops); 1035 inet6_del_protocol(&icmpv6_protocol, IPPROTO_ICMPV6); 1036 } 1037 1038 1039 static const struct icmp6_err { 1040 int err; 1041 int fatal; 1042 } tab_unreach[] = { 1043 { /* NOROUTE */ 1044 .err = ENETUNREACH, 1045 .fatal = 0, 1046 }, 1047 { /* ADM_PROHIBITED */ 1048 .err = EACCES, 1049 .fatal = 1, 1050 }, 1051 { /* Was NOT_NEIGHBOUR, now reserved */ 1052 .err = EHOSTUNREACH, 1053 .fatal = 0, 1054 }, 1055 { /* ADDR_UNREACH */ 1056 .err = EHOSTUNREACH, 1057 .fatal = 0, 1058 }, 1059 { /* PORT_UNREACH */ 1060 .err = ECONNREFUSED, 1061 .fatal = 1, 1062 }, 1063 { /* POLICY_FAIL */ 1064 .err = EACCES, 1065 .fatal = 1, 1066 }, 1067 { /* REJECT_ROUTE */ 1068 .err = EACCES, 1069 .fatal = 1, 1070 }, 1071 }; 1072 1073 int icmpv6_err_convert(u8 type, u8 code, int *err) 1074 { 1075 int fatal = 0; 1076 1077 *err = EPROTO; 1078 1079 switch (type) { 1080 case ICMPV6_DEST_UNREACH: 1081 fatal = 1; 1082 if (code < ARRAY_SIZE(tab_unreach)) { 1083 *err = tab_unreach[code].err; 1084 fatal = tab_unreach[code].fatal; 1085 } 1086 break; 1087 1088 case ICMPV6_PKT_TOOBIG: 1089 *err = EMSGSIZE; 1090 break; 1091 1092 case ICMPV6_PARAMPROB: 1093 *err = EPROTO; 1094 fatal = 1; 1095 break; 1096 1097 case ICMPV6_TIME_EXCEED: 1098 *err = EHOSTUNREACH; 1099 break; 1100 } 1101 1102 return fatal; 1103 } 1104 EXPORT_SYMBOL(icmpv6_err_convert); 1105 1106 #ifdef CONFIG_SYSCTL 1107 static struct ctl_table ipv6_icmp_table_template[] = { 1108 { 1109 .procname = "ratelimit", 1110 .data = &init_net.ipv6.sysctl.icmpv6_time, 1111 .maxlen = sizeof(int), 1112 .mode = 0644, 1113 .proc_handler = proc_dointvec_ms_jiffies, 1114 }, 1115 { 1116 .procname = "echo_ignore_all", 1117 .data = &init_net.ipv6.sysctl.icmpv6_echo_ignore_all, 1118 .maxlen = sizeof(int), 1119 .mode = 0644, 1120 .proc_handler = proc_dointvec, 1121 }, 1122 { 1123 .procname = "echo_ignore_multicast", 1124 .data = &init_net.ipv6.sysctl.icmpv6_echo_ignore_multicast, 1125 .maxlen = sizeof(int), 1126 .mode = 0644, 1127 .proc_handler = proc_dointvec, 1128 }, 1129 { }, 1130 }; 1131 1132 struct ctl_table * __net_init ipv6_icmp_sysctl_init(struct net *net) 1133 { 1134 struct ctl_table *table; 1135 1136 table = kmemdup(ipv6_icmp_table_template, 1137 sizeof(ipv6_icmp_table_template), 1138 GFP_KERNEL); 1139 1140 if (table) { 1141 table[0].data = &net->ipv6.sysctl.icmpv6_time; 1142 table[1].data = &net->ipv6.sysctl.icmpv6_echo_ignore_all; 1143 table[2].data = &net->ipv6.sysctl.icmpv6_echo_ignore_multicast; 1144 } 1145 return table; 1146 } 1147 #endif 1148