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, ntohl(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 dst = icmpv6_route_lookup(net, skb, sk, &fl6); 506 if (IS_ERR(dst)) 507 goto out; 508 509 ipc6.hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst); 510 ipc6.tclass = np->tclass; 511 ipc6.dontfrag = np->dontfrag; 512 ipc6.opt = NULL; 513 514 msg.skb = skb; 515 msg.offset = skb_network_offset(skb); 516 msg.type = type; 517 518 len = skb->len - msg.offset; 519 len = min_t(unsigned int, len, IPV6_MIN_MTU - sizeof(struct ipv6hdr) - sizeof(struct icmp6hdr)); 520 if (len < 0) { 521 net_dbg_ratelimited("icmp: len problem [%pI6c > %pI6c]\n", 522 &hdr->saddr, &hdr->daddr); 523 goto out_dst_release; 524 } 525 526 rcu_read_lock(); 527 idev = __in6_dev_get(skb->dev); 528 529 err = ip6_append_data(sk, icmpv6_getfrag, &msg, 530 len + sizeof(struct icmp6hdr), 531 sizeof(struct icmp6hdr), 532 &ipc6, &fl6, (struct rt6_info *)dst, 533 MSG_DONTWAIT, &sockc_unused); 534 if (err) { 535 ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTERRORS); 536 ip6_flush_pending_frames(sk); 537 } else { 538 err = icmpv6_push_pending_frames(sk, &fl6, &tmp_hdr, 539 len + sizeof(struct icmp6hdr)); 540 } 541 rcu_read_unlock(); 542 out_dst_release: 543 dst_release(dst); 544 out: 545 icmpv6_xmit_unlock(sk); 546 } 547 548 /* Slightly more convenient version of icmp6_send. 549 */ 550 void icmpv6_param_prob(struct sk_buff *skb, u8 code, int pos) 551 { 552 icmp6_send(skb, ICMPV6_PARAMPROB, code, pos); 553 kfree_skb(skb); 554 } 555 556 static void icmpv6_echo_reply(struct sk_buff *skb) 557 { 558 struct net *net = dev_net(skb->dev); 559 struct sock *sk; 560 struct inet6_dev *idev; 561 struct ipv6_pinfo *np; 562 const struct in6_addr *saddr = NULL; 563 struct icmp6hdr *icmph = icmp6_hdr(skb); 564 struct icmp6hdr tmp_hdr; 565 struct flowi6 fl6; 566 struct icmpv6_msg msg; 567 struct dst_entry *dst; 568 struct ipcm6_cookie ipc6; 569 int err = 0; 570 u32 mark = IP6_REPLY_MARK(net, skb->mark); 571 struct sockcm_cookie sockc_unused = {0}; 572 573 saddr = &ipv6_hdr(skb)->daddr; 574 575 if (!ipv6_unicast_destination(skb) && 576 !(net->ipv6.sysctl.anycast_src_echo_reply && 577 ipv6_anycast_destination(skb_dst(skb), saddr))) 578 saddr = NULL; 579 580 memcpy(&tmp_hdr, icmph, sizeof(tmp_hdr)); 581 tmp_hdr.icmp6_type = ICMPV6_ECHO_REPLY; 582 583 memset(&fl6, 0, sizeof(fl6)); 584 fl6.flowi6_proto = IPPROTO_ICMPV6; 585 fl6.daddr = ipv6_hdr(skb)->saddr; 586 if (saddr) 587 fl6.saddr = *saddr; 588 fl6.flowi6_oif = l3mdev_fib_oif(skb->dev); 589 fl6.fl6_icmp_type = ICMPV6_ECHO_REPLY; 590 fl6.flowi6_mark = mark; 591 security_skb_classify_flow(skb, flowi6_to_flowi(&fl6)); 592 593 sk = icmpv6_xmit_lock(net); 594 if (!sk) 595 return; 596 sk->sk_mark = mark; 597 np = inet6_sk(sk); 598 599 if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr)) 600 fl6.flowi6_oif = np->mcast_oif; 601 else if (!fl6.flowi6_oif) 602 fl6.flowi6_oif = np->ucast_oif; 603 604 err = ip6_dst_lookup(net, sk, &dst, &fl6); 605 if (err) 606 goto out; 607 dst = xfrm_lookup(net, dst, flowi6_to_flowi(&fl6), sk, 0); 608 if (IS_ERR(dst)) 609 goto out; 610 611 idev = __in6_dev_get(skb->dev); 612 613 msg.skb = skb; 614 msg.offset = 0; 615 msg.type = ICMPV6_ECHO_REPLY; 616 617 ipc6.hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst); 618 ipc6.tclass = ipv6_get_dsfield(ipv6_hdr(skb)); 619 ipc6.dontfrag = np->dontfrag; 620 ipc6.opt = NULL; 621 622 err = ip6_append_data(sk, icmpv6_getfrag, &msg, skb->len + sizeof(struct icmp6hdr), 623 sizeof(struct icmp6hdr), &ipc6, &fl6, 624 (struct rt6_info *)dst, MSG_DONTWAIT, 625 &sockc_unused); 626 627 if (err) { 628 __ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTERRORS); 629 ip6_flush_pending_frames(sk); 630 } else { 631 err = icmpv6_push_pending_frames(sk, &fl6, &tmp_hdr, 632 skb->len + sizeof(struct icmp6hdr)); 633 } 634 dst_release(dst); 635 out: 636 icmpv6_xmit_unlock(sk); 637 } 638 639 void icmpv6_notify(struct sk_buff *skb, u8 type, u8 code, __be32 info) 640 { 641 const struct inet6_protocol *ipprot; 642 int inner_offset; 643 __be16 frag_off; 644 u8 nexthdr; 645 struct net *net = dev_net(skb->dev); 646 647 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr))) 648 goto out; 649 650 nexthdr = ((struct ipv6hdr *)skb->data)->nexthdr; 651 if (ipv6_ext_hdr(nexthdr)) { 652 /* now skip over extension headers */ 653 inner_offset = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), 654 &nexthdr, &frag_off); 655 if (inner_offset < 0) 656 goto out; 657 } else { 658 inner_offset = sizeof(struct ipv6hdr); 659 } 660 661 /* Checkin header including 8 bytes of inner protocol header. */ 662 if (!pskb_may_pull(skb, inner_offset+8)) 663 goto out; 664 665 /* BUGGG_FUTURE: we should try to parse exthdrs in this packet. 666 Without this we will not able f.e. to make source routed 667 pmtu discovery. 668 Corresponding argument (opt) to notifiers is already added. 669 --ANK (980726) 670 */ 671 672 ipprot = rcu_dereference(inet6_protos[nexthdr]); 673 if (ipprot && ipprot->err_handler) 674 ipprot->err_handler(skb, NULL, type, code, inner_offset, info); 675 676 raw6_icmp_error(skb, nexthdr, type, code, inner_offset, info); 677 return; 678 679 out: 680 __ICMP6_INC_STATS(net, __in6_dev_get(skb->dev), ICMP6_MIB_INERRORS); 681 } 682 683 /* 684 * Handle icmp messages 685 */ 686 687 static int icmpv6_rcv(struct sk_buff *skb) 688 { 689 struct net_device *dev = skb->dev; 690 struct inet6_dev *idev = __in6_dev_get(dev); 691 const struct in6_addr *saddr, *daddr; 692 struct icmp6hdr *hdr; 693 u8 type; 694 bool success = false; 695 696 if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) { 697 struct sec_path *sp = skb_sec_path(skb); 698 int nh; 699 700 if (!(sp && sp->xvec[sp->len - 1]->props.flags & 701 XFRM_STATE_ICMP)) 702 goto drop_no_count; 703 704 if (!pskb_may_pull(skb, sizeof(*hdr) + sizeof(struct ipv6hdr))) 705 goto drop_no_count; 706 707 nh = skb_network_offset(skb); 708 skb_set_network_header(skb, sizeof(*hdr)); 709 710 if (!xfrm6_policy_check_reverse(NULL, XFRM_POLICY_IN, skb)) 711 goto drop_no_count; 712 713 skb_set_network_header(skb, nh); 714 } 715 716 __ICMP6_INC_STATS(dev_net(dev), idev, ICMP6_MIB_INMSGS); 717 718 saddr = &ipv6_hdr(skb)->saddr; 719 daddr = &ipv6_hdr(skb)->daddr; 720 721 if (skb_checksum_validate(skb, IPPROTO_ICMPV6, ip6_compute_pseudo)) { 722 net_dbg_ratelimited("ICMPv6 checksum failed [%pI6c > %pI6c]\n", 723 saddr, daddr); 724 goto csum_error; 725 } 726 727 if (!pskb_pull(skb, sizeof(*hdr))) 728 goto discard_it; 729 730 hdr = icmp6_hdr(skb); 731 732 type = hdr->icmp6_type; 733 734 ICMP6MSGIN_INC_STATS(dev_net(dev), idev, type); 735 736 switch (type) { 737 case ICMPV6_ECHO_REQUEST: 738 icmpv6_echo_reply(skb); 739 break; 740 741 case ICMPV6_ECHO_REPLY: 742 success = ping_rcv(skb); 743 break; 744 745 case ICMPV6_PKT_TOOBIG: 746 /* BUGGG_FUTURE: if packet contains rthdr, we cannot update 747 standard destination cache. Seems, only "advanced" 748 destination cache will allow to solve this problem 749 --ANK (980726) 750 */ 751 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr))) 752 goto discard_it; 753 hdr = icmp6_hdr(skb); 754 755 /* 756 * Drop through to notify 757 */ 758 759 case ICMPV6_DEST_UNREACH: 760 case ICMPV6_TIME_EXCEED: 761 case ICMPV6_PARAMPROB: 762 icmpv6_notify(skb, type, hdr->icmp6_code, hdr->icmp6_mtu); 763 break; 764 765 case NDISC_ROUTER_SOLICITATION: 766 case NDISC_ROUTER_ADVERTISEMENT: 767 case NDISC_NEIGHBOUR_SOLICITATION: 768 case NDISC_NEIGHBOUR_ADVERTISEMENT: 769 case NDISC_REDIRECT: 770 ndisc_rcv(skb); 771 break; 772 773 case ICMPV6_MGM_QUERY: 774 igmp6_event_query(skb); 775 break; 776 777 case ICMPV6_MGM_REPORT: 778 igmp6_event_report(skb); 779 break; 780 781 case ICMPV6_MGM_REDUCTION: 782 case ICMPV6_NI_QUERY: 783 case ICMPV6_NI_REPLY: 784 case ICMPV6_MLD2_REPORT: 785 case ICMPV6_DHAAD_REQUEST: 786 case ICMPV6_DHAAD_REPLY: 787 case ICMPV6_MOBILE_PREFIX_SOL: 788 case ICMPV6_MOBILE_PREFIX_ADV: 789 break; 790 791 default: 792 /* informational */ 793 if (type & ICMPV6_INFOMSG_MASK) 794 break; 795 796 net_dbg_ratelimited("icmpv6: msg of unknown type [%pI6c > %pI6c]\n", 797 saddr, daddr); 798 799 /* 800 * error of unknown type. 801 * must pass to upper level 802 */ 803 804 icmpv6_notify(skb, type, hdr->icmp6_code, hdr->icmp6_mtu); 805 } 806 807 /* until the v6 path can be better sorted assume failure and 808 * preserve the status quo behaviour for the rest of the paths to here 809 */ 810 if (success) 811 consume_skb(skb); 812 else 813 kfree_skb(skb); 814 815 return 0; 816 817 csum_error: 818 __ICMP6_INC_STATS(dev_net(dev), idev, ICMP6_MIB_CSUMERRORS); 819 discard_it: 820 __ICMP6_INC_STATS(dev_net(dev), idev, ICMP6_MIB_INERRORS); 821 drop_no_count: 822 kfree_skb(skb); 823 return 0; 824 } 825 826 void icmpv6_flow_init(struct sock *sk, struct flowi6 *fl6, 827 u8 type, 828 const struct in6_addr *saddr, 829 const struct in6_addr *daddr, 830 int oif) 831 { 832 memset(fl6, 0, sizeof(*fl6)); 833 fl6->saddr = *saddr; 834 fl6->daddr = *daddr; 835 fl6->flowi6_proto = IPPROTO_ICMPV6; 836 fl6->fl6_icmp_type = type; 837 fl6->fl6_icmp_code = 0; 838 fl6->flowi6_oif = oif; 839 security_sk_classify_flow(sk, flowi6_to_flowi(fl6)); 840 } 841 842 static int __net_init icmpv6_sk_init(struct net *net) 843 { 844 struct sock *sk; 845 int err, i, j; 846 847 net->ipv6.icmp_sk = 848 kzalloc(nr_cpu_ids * sizeof(struct sock *), GFP_KERNEL); 849 if (!net->ipv6.icmp_sk) 850 return -ENOMEM; 851 852 for_each_possible_cpu(i) { 853 err = inet_ctl_sock_create(&sk, PF_INET6, 854 SOCK_RAW, IPPROTO_ICMPV6, net); 855 if (err < 0) { 856 pr_err("Failed to initialize the ICMP6 control socket (err %d)\n", 857 err); 858 goto fail; 859 } 860 861 net->ipv6.icmp_sk[i] = sk; 862 863 /* Enough space for 2 64K ICMP packets, including 864 * sk_buff struct overhead. 865 */ 866 sk->sk_sndbuf = 2 * SKB_TRUESIZE(64 * 1024); 867 } 868 return 0; 869 870 fail: 871 for (j = 0; j < i; j++) 872 inet_ctl_sock_destroy(net->ipv6.icmp_sk[j]); 873 kfree(net->ipv6.icmp_sk); 874 return err; 875 } 876 877 static void __net_exit icmpv6_sk_exit(struct net *net) 878 { 879 int i; 880 881 for_each_possible_cpu(i) { 882 inet_ctl_sock_destroy(net->ipv6.icmp_sk[i]); 883 } 884 kfree(net->ipv6.icmp_sk); 885 } 886 887 static struct pernet_operations icmpv6_sk_ops = { 888 .init = icmpv6_sk_init, 889 .exit = icmpv6_sk_exit, 890 }; 891 892 int __init icmpv6_init(void) 893 { 894 int err; 895 896 err = register_pernet_subsys(&icmpv6_sk_ops); 897 if (err < 0) 898 return err; 899 900 err = -EAGAIN; 901 if (inet6_add_protocol(&icmpv6_protocol, IPPROTO_ICMPV6) < 0) 902 goto fail; 903 904 err = inet6_register_icmp_sender(icmp6_send); 905 if (err) 906 goto sender_reg_err; 907 return 0; 908 909 sender_reg_err: 910 inet6_del_protocol(&icmpv6_protocol, IPPROTO_ICMPV6); 911 fail: 912 pr_err("Failed to register ICMP6 protocol\n"); 913 unregister_pernet_subsys(&icmpv6_sk_ops); 914 return err; 915 } 916 917 void icmpv6_cleanup(void) 918 { 919 inet6_unregister_icmp_sender(icmp6_send); 920 unregister_pernet_subsys(&icmpv6_sk_ops); 921 inet6_del_protocol(&icmpv6_protocol, IPPROTO_ICMPV6); 922 } 923 924 925 static const struct icmp6_err { 926 int err; 927 int fatal; 928 } tab_unreach[] = { 929 { /* NOROUTE */ 930 .err = ENETUNREACH, 931 .fatal = 0, 932 }, 933 { /* ADM_PROHIBITED */ 934 .err = EACCES, 935 .fatal = 1, 936 }, 937 { /* Was NOT_NEIGHBOUR, now reserved */ 938 .err = EHOSTUNREACH, 939 .fatal = 0, 940 }, 941 { /* ADDR_UNREACH */ 942 .err = EHOSTUNREACH, 943 .fatal = 0, 944 }, 945 { /* PORT_UNREACH */ 946 .err = ECONNREFUSED, 947 .fatal = 1, 948 }, 949 { /* POLICY_FAIL */ 950 .err = EACCES, 951 .fatal = 1, 952 }, 953 { /* REJECT_ROUTE */ 954 .err = EACCES, 955 .fatal = 1, 956 }, 957 }; 958 959 int icmpv6_err_convert(u8 type, u8 code, int *err) 960 { 961 int fatal = 0; 962 963 *err = EPROTO; 964 965 switch (type) { 966 case ICMPV6_DEST_UNREACH: 967 fatal = 1; 968 if (code < ARRAY_SIZE(tab_unreach)) { 969 *err = tab_unreach[code].err; 970 fatal = tab_unreach[code].fatal; 971 } 972 break; 973 974 case ICMPV6_PKT_TOOBIG: 975 *err = EMSGSIZE; 976 break; 977 978 case ICMPV6_PARAMPROB: 979 *err = EPROTO; 980 fatal = 1; 981 break; 982 983 case ICMPV6_TIME_EXCEED: 984 *err = EHOSTUNREACH; 985 break; 986 } 987 988 return fatal; 989 } 990 EXPORT_SYMBOL(icmpv6_err_convert); 991 992 #ifdef CONFIG_SYSCTL 993 static struct ctl_table ipv6_icmp_table_template[] = { 994 { 995 .procname = "ratelimit", 996 .data = &init_net.ipv6.sysctl.icmpv6_time, 997 .maxlen = sizeof(int), 998 .mode = 0644, 999 .proc_handler = proc_dointvec_ms_jiffies, 1000 }, 1001 { }, 1002 }; 1003 1004 struct ctl_table * __net_init ipv6_icmp_sysctl_init(struct net *net) 1005 { 1006 struct ctl_table *table; 1007 1008 table = kmemdup(ipv6_icmp_table_template, 1009 sizeof(ipv6_icmp_table_template), 1010 GFP_KERNEL); 1011 1012 if (table) 1013 table[0].data = &net->ipv6.sysctl.icmpv6_time; 1014 1015 return table; 1016 } 1017 #endif 1018