icmp.c 23 KB
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020
/*
 *	Internet Control Message Protocol (ICMPv6)
 *	Linux INET6 implementation
 *
 *	Authors:
 *	Pedro Roque		<roque@di.fc.ul.pt>
 *
 *	Based on net/ipv4/icmp.c
 *
 *	RFC 1885
 *
 *	This program is free software; you can redistribute it and/or
 *      modify it under the terms of the GNU General Public License
 *      as published by the Free Software Foundation; either version
 *      2 of the License, or (at your option) any later version.
 */

/*
 *	Changes:
 *
 *	Andi Kleen		:	exception handling
 *	Andi Kleen			add rate limits. never reply to a icmp.
 *					add more length checks and other fixes.
 *	yoshfuji		:	ensure to sent parameter problem for
 *					fragments.
 *	YOSHIFUJI Hideaki @USAGI:	added sysctl for icmp rate limit.
 *	Randy Dunlap and
 *	YOSHIFUJI Hideaki @USAGI:	Per-interface statistics support
 *	Kazunori MIYAZAWA @USAGI:       change output process to use ip6_append_data
 */

#define pr_fmt(fmt) "IPv6: " fmt

#include <linux/module.h>
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/in.h>
#include <linux/kernel.h>
#include <linux/sockios.h>
#include <linux/net.h>
#include <linux/skbuff.h>
#include <linux/init.h>
#include <linux/netfilter.h>
#include <linux/slab.h>

#ifdef CONFIG_SYSCTL
#include <linux/sysctl.h>
#endif

#include <linux/inet.h>
#include <linux/netdevice.h>
#include <linux/icmpv6.h>

#include <net/ip.h>
#include <net/sock.h>

#include <net/ipv6.h>
#include <net/ip6_checksum.h>
#include <net/ping.h>
#include <net/protocol.h>
#include <net/raw.h>
#include <net/rawv6.h>
#include <net/transp_v6.h>
#include <net/ip6_route.h>
#include <net/addrconf.h>
#include <net/icmp.h>
#include <net/xfrm.h>
#include <net/inet_common.h>
#include <net/dsfield.h>

#include <asm/uaccess.h>

/*
 *	The ICMP socket(s). This is the most convenient way to flow control
 *	our ICMP output as well as maintain a clean interface throughout
 *	all layers. All Socketless IP sends will soon be gone.
 *
 *	On SMP we have one ICMP socket per-cpu.
 */
static inline struct sock *icmpv6_sk(struct net *net)
{
	return net->ipv6.icmp_sk[smp_processor_id()];
}

static void icmpv6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
		       u8 type, u8 code, int offset, __be32 info)
{
	/* icmpv6_notify checks 8 bytes can be pulled, icmp6hdr is 8 bytes */
	struct icmp6hdr *icmp6 = (struct icmp6hdr *) (skb->data + offset);
	struct net *net = dev_net(skb->dev);

	if (type == ICMPV6_PKT_TOOBIG)
		ip6_update_pmtu(skb, net, info, 0, 0);
	else if (type == NDISC_REDIRECT)
		ip6_redirect(skb, net, skb->dev->ifindex, 0);

	if (!(type & ICMPV6_INFOMSG_MASK))
		if (icmp6->icmp6_type == ICMPV6_ECHO_REQUEST)
			ping_err(skb, offset, info);
}

static int icmpv6_rcv(struct sk_buff *skb);

static const struct inet6_protocol icmpv6_protocol = {
	.handler	=	icmpv6_rcv,
	.err_handler	=	icmpv6_err,
	.flags		=	INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
};

static __inline__ struct sock *icmpv6_xmit_lock(struct net *net)
{
	struct sock *sk;

	local_bh_disable();

	sk = icmpv6_sk(net);
	if (unlikely(!spin_trylock(&sk->sk_lock.slock))) {
		/* This can happen if the output path (f.e. SIT or
		 * ip6ip6 tunnel) signals dst_link_failure() for an
		 * outgoing ICMP6 packet.
		 */
		local_bh_enable();
		return NULL;
	}
	return sk;
}

static __inline__ void icmpv6_xmit_unlock(struct sock *sk)
{
	spin_unlock_bh(&sk->sk_lock.slock);
}

/*
 * Figure out, may we reply to this packet with icmp error.
 *
 * We do not reply, if:
 *	- it was icmp error message.
 *	- it is truncated, so that it is known, that protocol is ICMPV6
 *	  (i.e. in the middle of some exthdr)
 *
 *	--ANK (980726)
 */

static bool is_ineligible(const struct sk_buff *skb)
{
	int ptr = (u8 *)(ipv6_hdr(skb) + 1) - skb->data;
	int len = skb->len - ptr;
	__u8 nexthdr = ipv6_hdr(skb)->nexthdr;
	__be16 frag_off;

	if (len < 0)
		return true;

	ptr = ipv6_skip_exthdr(skb, ptr, &nexthdr, &frag_off);
	if (ptr < 0)
		return false;
	if (nexthdr == IPPROTO_ICMPV6) {
		u8 _type, *tp;
		tp = skb_header_pointer(skb,
			ptr+offsetof(struct icmp6hdr, icmp6_type),
			sizeof(_type), &_type);
		if (tp == NULL ||
		    !(*tp & ICMPV6_INFOMSG_MASK))
			return true;
	}
	return false;
}

/*
 * Check the ICMP output rate limit
 */
static inline bool icmpv6_xrlim_allow(struct sock *sk, u8 type,
				      struct flowi6 *fl6)
{
	struct dst_entry *dst;
	struct net *net = sock_net(sk);
	bool res = false;

	/* Informational messages are not limited. */
	if (type & ICMPV6_INFOMSG_MASK)
		return true;

	/* Do not limit pmtu discovery, it would break it. */
	if (type == ICMPV6_PKT_TOOBIG)
		return true;

	/*
	 * Look up the output route.
	 * XXX: perhaps the expire for routing entries cloned by
	 * this lookup should be more aggressive (not longer than timeout).
	 */
	dst = ip6_route_output(net, sk, fl6);
	if (dst->error) {
		IP6_INC_STATS(net, ip6_dst_idev(dst),
			      IPSTATS_MIB_OUTNOROUTES);
	} else if (dst->dev && (dst->dev->flags&IFF_LOOPBACK)) {
		res = true;
	} else {
		struct rt6_info *rt = (struct rt6_info *)dst;
		int tmo = net->ipv6.sysctl.icmpv6_time;
		struct inet_peer *peer;

		/* Give more bandwidth to wider prefixes. */
		if (rt->rt6i_dst.plen < 128)
			tmo >>= ((128 - rt->rt6i_dst.plen)>>5);

		peer = inet_getpeer_v6(net->ipv6.peers, &rt->rt6i_dst.addr, 1);
		res = inet_peer_xrlim_allow(peer, tmo);
		if (peer)
			inet_putpeer(peer);
	}
	dst_release(dst);
	return res;
}

/*
 *	an inline helper for the "simple" if statement below
 *	checks if parameter problem report is caused by an
 *	unrecognized IPv6 option that has the Option Type
 *	highest-order two bits set to 10
 */

static bool opt_unrec(struct sk_buff *skb, __u32 offset)
{
	u8 _optval, *op;

	offset += skb_network_offset(skb);
	op = skb_header_pointer(skb, offset, sizeof(_optval), &_optval);
	if (op == NULL)
		return true;
	return (*op & 0xC0) == 0x80;
}

int icmpv6_push_pending_frames(struct sock *sk, struct flowi6 *fl6,
			       struct icmp6hdr *thdr, int len)
{
	struct sk_buff *skb;
	struct icmp6hdr *icmp6h;
	int err = 0;

	if ((skb = skb_peek(&sk->sk_write_queue)) == NULL)
		goto out;

	icmp6h = icmp6_hdr(skb);
	memcpy(icmp6h, thdr, sizeof(struct icmp6hdr));
	icmp6h->icmp6_cksum = 0;

	if (skb_queue_len(&sk->sk_write_queue) == 1) {
		skb->csum = csum_partial(icmp6h,
					sizeof(struct icmp6hdr), skb->csum);
		icmp6h->icmp6_cksum = csum_ipv6_magic(&fl6->saddr,
						      &fl6->daddr,
						      len, fl6->flowi6_proto,
						      skb->csum);
	} else {
		__wsum tmp_csum = 0;

		skb_queue_walk(&sk->sk_write_queue, skb) {
			tmp_csum = csum_add(tmp_csum, skb->csum);
		}

		tmp_csum = csum_partial(icmp6h,
					sizeof(struct icmp6hdr), tmp_csum);
		icmp6h->icmp6_cksum = csum_ipv6_magic(&fl6->saddr,
						      &fl6->daddr,
						      len, fl6->flowi6_proto,
						      tmp_csum);
	}
	ip6_push_pending_frames(sk);
out:
	return err;
}

struct icmpv6_msg {
	struct sk_buff	*skb;
	int		offset;
	uint8_t		type;
};

static int icmpv6_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb)
{
	struct icmpv6_msg *msg = (struct icmpv6_msg *) from;
	struct sk_buff *org_skb = msg->skb;
	__wsum csum = 0;

	csum = skb_copy_and_csum_bits(org_skb, msg->offset + offset,
				      to, len, csum);
	skb->csum = csum_block_add(skb->csum, csum, odd);
	if (!(msg->type & ICMPV6_INFOMSG_MASK))
		nf_ct_attach(skb, org_skb);
	return 0;
}

#if IS_ENABLED(CONFIG_IPV6_MIP6)
static void mip6_addr_swap(struct sk_buff *skb)
{
	struct ipv6hdr *iph = ipv6_hdr(skb);
	struct inet6_skb_parm *opt = IP6CB(skb);
	struct ipv6_destopt_hao *hao;
	struct in6_addr tmp;
	int off;

	if (opt->dsthao) {
		off = ipv6_find_tlv(skb, opt->dsthao, IPV6_TLV_HAO);
		if (likely(off >= 0)) {
			hao = (struct ipv6_destopt_hao *)
					(skb_network_header(skb) + off);
			tmp = iph->saddr;
			iph->saddr = hao->addr;
			hao->addr = tmp;
		}
	}
}
#else
static inline void mip6_addr_swap(struct sk_buff *skb) {}
#endif

static struct dst_entry *icmpv6_route_lookup(struct net *net,
					     struct sk_buff *skb,
					     struct sock *sk,
					     struct flowi6 *fl6)
{
	struct dst_entry *dst, *dst2;
	struct flowi6 fl2;
	int err;

	err = ip6_dst_lookup(sk, &dst, fl6);
	if (err)
		return ERR_PTR(err);

	/*
	 * We won't send icmp if the destination is known
	 * anycast.
	 */
	if (((struct rt6_info *)dst)->rt6i_flags & RTF_ANYCAST) {
		LIMIT_NETDEBUG(KERN_DEBUG "icmp6_send: acast source\n");
		dst_release(dst);
		return ERR_PTR(-EINVAL);
	}

	/* No need to clone since we're just using its address. */
	dst2 = dst;

	dst = xfrm_lookup(net, dst, flowi6_to_flowi(fl6), sk, 0);
	if (!IS_ERR(dst)) {
		if (dst != dst2)
			return dst;
	} else {
		if (PTR_ERR(dst) == -EPERM)
			dst = NULL;
		else
			return dst;
	}

	err = xfrm_decode_session_reverse(skb, flowi6_to_flowi(&fl2), AF_INET6);
	if (err)
		goto relookup_failed;

	err = ip6_dst_lookup(sk, &dst2, &fl2);
	if (err)
		goto relookup_failed;

	dst2 = xfrm_lookup(net, dst2, flowi6_to_flowi(&fl2), sk, XFRM_LOOKUP_ICMP);
	if (!IS_ERR(dst2)) {
		dst_release(dst);
		dst = dst2;
	} else {
		err = PTR_ERR(dst2);
		if (err == -EPERM) {
			dst_release(dst);
			return dst2;
		} else
			goto relookup_failed;
	}

relookup_failed:
	if (dst)
		return dst;
	return ERR_PTR(err);
}

/*
 *	Send an ICMP message in response to a packet in error
 */
static void icmp6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info)
{
	struct net *net = dev_net(skb->dev);
	struct inet6_dev *idev = NULL;
	struct ipv6hdr *hdr = ipv6_hdr(skb);
	struct sock *sk;
	struct ipv6_pinfo *np;
	const struct in6_addr *saddr = NULL;
	struct dst_entry *dst;
	struct icmp6hdr tmp_hdr;
	struct flowi6 fl6;
	struct icmpv6_msg msg;
	int iif = 0;
	int addr_type = 0;
	int len;
	int hlimit;
	int err = 0;

	if ((u8 *)hdr < skb->head ||
	    (skb_network_header(skb) + sizeof(*hdr)) > skb_tail_pointer(skb))
		return;

	/*
	 *	Make sure we respect the rules
	 *	i.e. RFC 1885 2.4(e)
	 *	Rule (e.1) is enforced by not using icmp6_send
	 *	in any code that processes icmp errors.
	 */
	addr_type = ipv6_addr_type(&hdr->daddr);

	if (ipv6_chk_addr(net, &hdr->daddr, skb->dev, 0) ||
	    ipv6_chk_acast_addr_src(net, skb->dev, &hdr->daddr))
		saddr = &hdr->daddr;

	/*
	 *	Dest addr check
	 */

	if ((addr_type & IPV6_ADDR_MULTICAST || skb->pkt_type != PACKET_HOST)) {
		if (type != ICMPV6_PKT_TOOBIG &&
		    !(type == ICMPV6_PARAMPROB &&
		      code == ICMPV6_UNK_OPTION &&
		      (opt_unrec(skb, info))))
			return;

		saddr = NULL;
	}

	addr_type = ipv6_addr_type(&hdr->saddr);

	/*
	 *	Source addr check
	 */

	if (__ipv6_addr_needs_scope_id(addr_type))
		iif = skb->dev->ifindex;

	/*
	 *	Must not send error if the source does not uniquely
	 *	identify a single node (RFC2463 Section 2.4).
	 *	We check unspecified / multicast addresses here,
	 *	and anycast addresses will be checked later.
	 */
	if ((addr_type == IPV6_ADDR_ANY) || (addr_type & IPV6_ADDR_MULTICAST)) {
		LIMIT_NETDEBUG(KERN_DEBUG "icmp6_send: addr_any/mcast source\n");
		return;
	}

	/*
	 *	Never answer to a ICMP packet.
	 */
	if (is_ineligible(skb)) {
		LIMIT_NETDEBUG(KERN_DEBUG "icmp6_send: no reply to icmp error\n");
		return;
	}

	mip6_addr_swap(skb);

	memset(&fl6, 0, sizeof(fl6));
	fl6.flowi6_proto = IPPROTO_ICMPV6;
	fl6.daddr = hdr->saddr;
	if (saddr)
		fl6.saddr = *saddr;
	fl6.flowi6_oif = iif;
	fl6.fl6_icmp_type = type;
	fl6.fl6_icmp_code = code;
	security_skb_classify_flow(skb, flowi6_to_flowi(&fl6));

	sk = icmpv6_xmit_lock(net);
	if (sk == NULL)
		return;
	np = inet6_sk(sk);

	if (!icmpv6_xrlim_allow(sk, type, &fl6))
		goto out;

	tmp_hdr.icmp6_type = type;
	tmp_hdr.icmp6_code = code;
	tmp_hdr.icmp6_cksum = 0;
	tmp_hdr.icmp6_pointer = htonl(info);

	if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr))
		fl6.flowi6_oif = np->mcast_oif;
	else if (!fl6.flowi6_oif)
		fl6.flowi6_oif = np->ucast_oif;

	dst = icmpv6_route_lookup(net, skb, sk, &fl6);
	if (IS_ERR(dst))
		goto out;

	if (ipv6_addr_is_multicast(&fl6.daddr))
		hlimit = np->mcast_hops;
	else
		hlimit = np->hop_limit;
	if (hlimit < 0)
		hlimit = ip6_dst_hoplimit(dst);

	msg.skb = skb;
	msg.offset = skb_network_offset(skb);
	msg.type = type;

	len = skb->len - msg.offset;
	len = min_t(unsigned int, len, IPV6_MIN_MTU - sizeof(struct ipv6hdr) -sizeof(struct icmp6hdr));
	if (len < 0) {
		LIMIT_NETDEBUG(KERN_DEBUG "icmp: len problem\n");
		goto out_dst_release;
	}

	rcu_read_lock();
	idev = __in6_dev_get(skb->dev);

	err = ip6_append_data(sk, icmpv6_getfrag, &msg,
			      len + sizeof(struct icmp6hdr),
			      sizeof(struct icmp6hdr), hlimit,
			      np->tclass, NULL, &fl6, (struct rt6_info *)dst,
			      MSG_DONTWAIT, np->dontfrag);
	if (err) {
		ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTERRORS);
		ip6_flush_pending_frames(sk);
	} else {
		err = icmpv6_push_pending_frames(sk, &fl6, &tmp_hdr,
						 len + sizeof(struct icmp6hdr));
	}
	rcu_read_unlock();
out_dst_release:
	dst_release(dst);
out:
	icmpv6_xmit_unlock(sk);
}

/* Slightly more convenient version of icmp6_send.
 */
void icmpv6_param_prob(struct sk_buff *skb, u8 code, int pos)
{
	icmp6_send(skb, ICMPV6_PARAMPROB, code, pos);
	kfree_skb(skb);
}

static void icmpv6_echo_reply(struct sk_buff *skb)
{
	struct net *net = dev_net(skb->dev);
	struct sock *sk;
	struct inet6_dev *idev;
	struct ipv6_pinfo *np;
	const struct in6_addr *saddr = NULL;
	struct icmp6hdr *icmph = icmp6_hdr(skb);
	struct icmp6hdr tmp_hdr;
	struct flowi6 fl6;
	struct icmpv6_msg msg;
	struct dst_entry *dst;
	int err = 0;
	int hlimit;
	u8 tclass;

	saddr = &ipv6_hdr(skb)->daddr;

	if (!ipv6_unicast_destination(skb) &&
	    !(net->ipv6.sysctl.anycast_src_echo_reply &&
	      ipv6_anycast_destination(skb)))
		saddr = NULL;

	memcpy(&tmp_hdr, icmph, sizeof(tmp_hdr));
	tmp_hdr.icmp6_type = ICMPV6_ECHO_REPLY;

	memset(&fl6, 0, sizeof(fl6));
	fl6.flowi6_proto = IPPROTO_ICMPV6;
	fl6.daddr = ipv6_hdr(skb)->saddr;
	if (saddr)
		fl6.saddr = *saddr;
	fl6.flowi6_oif = skb->dev->ifindex;
	fl6.fl6_icmp_type = ICMPV6_ECHO_REPLY;
	security_skb_classify_flow(skb, flowi6_to_flowi(&fl6));

	sk = icmpv6_xmit_lock(net);
	if (sk == NULL)
		return;
	np = inet6_sk(sk);

	if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr))
		fl6.flowi6_oif = np->mcast_oif;
	else if (!fl6.flowi6_oif)
		fl6.flowi6_oif = np->ucast_oif;

	err = ip6_dst_lookup(sk, &dst, &fl6);
	if (err)
		goto out;
	dst = xfrm_lookup(net, dst, flowi6_to_flowi(&fl6), sk, 0);
	if (IS_ERR(dst))
		goto out;

	if (ipv6_addr_is_multicast(&fl6.daddr))
		hlimit = np->mcast_hops;
	else
		hlimit = np->hop_limit;
	if (hlimit < 0)
		hlimit = ip6_dst_hoplimit(dst);

	idev = __in6_dev_get(skb->dev);

	msg.skb = skb;
	msg.offset = 0;
	msg.type = ICMPV6_ECHO_REPLY;

	tclass = ipv6_get_dsfield(ipv6_hdr(skb));
	err = ip6_append_data(sk, icmpv6_getfrag, &msg, skb->len + sizeof(struct icmp6hdr),
				sizeof(struct icmp6hdr), hlimit, tclass, NULL, &fl6,
				(struct rt6_info *)dst, MSG_DONTWAIT,
				np->dontfrag);

	if (err) {
		ICMP6_INC_STATS_BH(net, idev, ICMP6_MIB_OUTERRORS);
		ip6_flush_pending_frames(sk);
	} else {
		err = icmpv6_push_pending_frames(sk, &fl6, &tmp_hdr,
						 skb->len + sizeof(struct icmp6hdr));
	}
	dst_release(dst);
out:
	icmpv6_xmit_unlock(sk);
}

void icmpv6_notify(struct sk_buff *skb, u8 type, u8 code, __be32 info)
{
	const struct inet6_protocol *ipprot;
	int inner_offset;
	__be16 frag_off;
	u8 nexthdr;

	if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
		return;

	nexthdr = ((struct ipv6hdr *)skb->data)->nexthdr;
	if (ipv6_ext_hdr(nexthdr)) {
		/* now skip over extension headers */
		inner_offset = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr),
						&nexthdr, &frag_off);
		if (inner_offset<0)
			return;
	} else {
		inner_offset = sizeof(struct ipv6hdr);
	}

	/* Checkin header including 8 bytes of inner protocol header. */
	if (!pskb_may_pull(skb, inner_offset+8))
		return;

	/* BUGGG_FUTURE: we should try to parse exthdrs in this packet.
	   Without this we will not able f.e. to make source routed
	   pmtu discovery.
	   Corresponding argument (opt) to notifiers is already added.
	   --ANK (980726)
	 */

	rcu_read_lock();
	ipprot = rcu_dereference(inet6_protos[nexthdr]);
	if (ipprot && ipprot->err_handler)
		ipprot->err_handler(skb, NULL, type, code, inner_offset, info);
	rcu_read_unlock();

	raw6_icmp_error(skb, nexthdr, type, code, inner_offset, info);
}

/*
 *	Handle icmp messages
 */

static int icmpv6_rcv(struct sk_buff *skb)
{
	struct net_device *dev = skb->dev;
	struct inet6_dev *idev = __in6_dev_get(dev);
	const struct in6_addr *saddr, *daddr;
	struct icmp6hdr *hdr;
	u8 type;

	if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
		struct sec_path *sp = skb_sec_path(skb);
		int nh;

		if (!(sp && sp->xvec[sp->len - 1]->props.flags &
				 XFRM_STATE_ICMP))
			goto drop_no_count;

		if (!pskb_may_pull(skb, sizeof(*hdr) + sizeof(struct ipv6hdr)))
			goto drop_no_count;

		nh = skb_network_offset(skb);
		skb_set_network_header(skb, sizeof(*hdr));

		if (!xfrm6_policy_check_reverse(NULL, XFRM_POLICY_IN, skb))
			goto drop_no_count;

		skb_set_network_header(skb, nh);
	}

	ICMP6_INC_STATS_BH(dev_net(dev), idev, ICMP6_MIB_INMSGS);

	saddr = &ipv6_hdr(skb)->saddr;
	daddr = &ipv6_hdr(skb)->daddr;

	/* Perform checksum. */
	switch (skb->ip_summed) {
	case CHECKSUM_COMPLETE:
		if (!csum_ipv6_magic(saddr, daddr, skb->len, IPPROTO_ICMPV6,
				     skb->csum))
			break;
		/* fall through */
	case CHECKSUM_NONE:
		skb->csum = ~csum_unfold(csum_ipv6_magic(saddr, daddr, skb->len,
					     IPPROTO_ICMPV6, 0));
		if (__skb_checksum_complete(skb)) {
			LIMIT_NETDEBUG(KERN_DEBUG
				       "ICMPv6 checksum failed [%pI6c > %pI6c]\n",
				       saddr, daddr);
			goto csum_error;
		}
	}

	if (!pskb_pull(skb, sizeof(*hdr)))
		goto discard_it;

	hdr = icmp6_hdr(skb);

	type = hdr->icmp6_type;

	ICMP6MSGIN_INC_STATS_BH(dev_net(dev), idev, type);

	switch (type) {
	case ICMPV6_ECHO_REQUEST:
		icmpv6_echo_reply(skb);
		break;

	case ICMPV6_ECHO_REPLY:
		ping_rcv(skb);
		break;

	case ICMPV6_PKT_TOOBIG:
		/* BUGGG_FUTURE: if packet contains rthdr, we cannot update
		   standard destination cache. Seems, only "advanced"
		   destination cache will allow to solve this problem
		   --ANK (980726)
		 */
		if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
			goto discard_it;
		hdr = icmp6_hdr(skb);

		/*
		 *	Drop through to notify
		 */

	case ICMPV6_DEST_UNREACH:
	case ICMPV6_TIME_EXCEED:
	case ICMPV6_PARAMPROB:
		icmpv6_notify(skb, type, hdr->icmp6_code, hdr->icmp6_mtu);
		break;

	case NDISC_ROUTER_SOLICITATION:
	case NDISC_ROUTER_ADVERTISEMENT:
	case NDISC_NEIGHBOUR_SOLICITATION:
	case NDISC_NEIGHBOUR_ADVERTISEMENT:
	case NDISC_REDIRECT:
		ndisc_rcv(skb);
		break;

	case ICMPV6_MGM_QUERY:
		igmp6_event_query(skb);
		break;

	case ICMPV6_MGM_REPORT:
		igmp6_event_report(skb);
		break;

	case ICMPV6_MGM_REDUCTION:
	case ICMPV6_NI_QUERY:
	case ICMPV6_NI_REPLY:
	case ICMPV6_MLD2_REPORT:
	case ICMPV6_DHAAD_REQUEST:
	case ICMPV6_DHAAD_REPLY:
	case ICMPV6_MOBILE_PREFIX_SOL:
	case ICMPV6_MOBILE_PREFIX_ADV:
		break;

	default:
		LIMIT_NETDEBUG(KERN_DEBUG "icmpv6: msg of unknown type\n");

		/* informational */
		if (type & ICMPV6_INFOMSG_MASK)
			break;

		/*
		 * error of unknown type.
		 * must pass to upper level
		 */

		icmpv6_notify(skb, type, hdr->icmp6_code, hdr->icmp6_mtu);
	}

	kfree_skb(skb);
	return 0;

csum_error:
	ICMP6_INC_STATS_BH(dev_net(dev), idev, ICMP6_MIB_CSUMERRORS);
discard_it:
	ICMP6_INC_STATS_BH(dev_net(dev), idev, ICMP6_MIB_INERRORS);
drop_no_count:
	kfree_skb(skb);
	return 0;
}

void icmpv6_flow_init(struct sock *sk, struct flowi6 *fl6,
		      u8 type,
		      const struct in6_addr *saddr,
		      const struct in6_addr *daddr,
		      int oif)
{
	memset(fl6, 0, sizeof(*fl6));
	fl6->saddr = *saddr;
	fl6->daddr = *daddr;
	fl6->flowi6_proto 	= IPPROTO_ICMPV6;
	fl6->fl6_icmp_type	= type;
	fl6->fl6_icmp_code	= 0;
	fl6->flowi6_oif		= oif;
	security_sk_classify_flow(sk, flowi6_to_flowi(fl6));
}

/*
 * Special lock-class for __icmpv6_sk:
 */
static struct lock_class_key icmpv6_socket_sk_dst_lock_key;

static int __net_init icmpv6_sk_init(struct net *net)
{
	struct sock *sk;
	int err, i, j;

	net->ipv6.icmp_sk =
		kzalloc(nr_cpu_ids * sizeof(struct sock *), GFP_KERNEL);
	if (net->ipv6.icmp_sk == NULL)
		return -ENOMEM;

	for_each_possible_cpu(i) {
		err = inet_ctl_sock_create(&sk, PF_INET6,
					   SOCK_RAW, IPPROTO_ICMPV6, net);
		if (err < 0) {
			pr_err("Failed to initialize the ICMP6 control socket (err %d)\n",
			       err);
			goto fail;
		}

		net->ipv6.icmp_sk[i] = sk;

		/*
		 * Split off their lock-class, because sk->sk_dst_lock
		 * gets used from softirqs, which is safe for
		 * __icmpv6_sk (because those never get directly used
		 * via userspace syscalls), but unsafe for normal sockets.
		 */
		lockdep_set_class(&sk->sk_dst_lock,
				  &icmpv6_socket_sk_dst_lock_key);

		/* Enough space for 2 64K ICMP packets, including
		 * sk_buff struct overhead.
		 */
		sk->sk_sndbuf = 2 * SKB_TRUESIZE(64 * 1024);
	}
	return 0;

 fail:
	for (j = 0; j < i; j++)
		inet_ctl_sock_destroy(net->ipv6.icmp_sk[j]);
	kfree(net->ipv6.icmp_sk);
	return err;
}

static void __net_exit icmpv6_sk_exit(struct net *net)
{
	int i;

	for_each_possible_cpu(i) {
		inet_ctl_sock_destroy(net->ipv6.icmp_sk[i]);
	}
	kfree(net->ipv6.icmp_sk);
}

static struct pernet_operations icmpv6_sk_ops = {
       .init = icmpv6_sk_init,
       .exit = icmpv6_sk_exit,
};

int __init icmpv6_init(void)
{
	int err;

	err = register_pernet_subsys(&icmpv6_sk_ops);
	if (err < 0)
		return err;

	err = -EAGAIN;
	if (inet6_add_protocol(&icmpv6_protocol, IPPROTO_ICMPV6) < 0)
		goto fail;

	err = inet6_register_icmp_sender(icmp6_send);
	if (err)
		goto sender_reg_err;
	return 0;

sender_reg_err:
	inet6_del_protocol(&icmpv6_protocol, IPPROTO_ICMPV6);
fail:
	pr_err("Failed to register ICMP6 protocol\n");
	unregister_pernet_subsys(&icmpv6_sk_ops);
	return err;
}

void icmpv6_cleanup(void)
{
	inet6_unregister_icmp_sender(icmp6_send);
	unregister_pernet_subsys(&icmpv6_sk_ops);
	inet6_del_protocol(&icmpv6_protocol, IPPROTO_ICMPV6);
}


static const struct icmp6_err {
	int err;
	int fatal;
} tab_unreach[] = {
	{	/* NOROUTE */
		.err	= ENETUNREACH,
		.fatal	= 0,
	},
	{	/* ADM_PROHIBITED */
		.err	= EACCES,
		.fatal	= 1,
	},
	{	/* Was NOT_NEIGHBOUR, now reserved */
		.err	= EHOSTUNREACH,
		.fatal	= 0,
	},
	{	/* ADDR_UNREACH	*/
		.err	= EHOSTUNREACH,
		.fatal	= 0,
	},
	{	/* PORT_UNREACH	*/
		.err	= ECONNREFUSED,
		.fatal	= 1,
	},
	{	/* POLICY_FAIL */
		.err	= EACCES,
		.fatal	= 1,
	},
	{	/* REJECT_ROUTE	*/
		.err	= EACCES,
		.fatal	= 1,
	},
};

int icmpv6_err_convert(u8 type, u8 code, int *err)
{
	int fatal = 0;

	*err = EPROTO;

	switch (type) {
	case ICMPV6_DEST_UNREACH:
		fatal = 1;
		if (code < ARRAY_SIZE(tab_unreach)) {
			*err  = tab_unreach[code].err;
			fatal = tab_unreach[code].fatal;
		}
		break;

	case ICMPV6_PKT_TOOBIG:
		*err = EMSGSIZE;
		break;

	case ICMPV6_PARAMPROB:
		*err = EPROTO;
		fatal = 1;
		break;

	case ICMPV6_TIME_EXCEED:
		*err = EHOSTUNREACH;
		break;
	}

	return fatal;
}
EXPORT_SYMBOL(icmpv6_err_convert);

#ifdef CONFIG_SYSCTL
static struct ctl_table ipv6_icmp_table_template[] = {
	{
		.procname	= "ratelimit",
		.data		= &init_net.ipv6.sysctl.icmpv6_time,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= proc_dointvec_ms_jiffies,
	},
	{ },
};

struct ctl_table * __net_init ipv6_icmp_sysctl_init(struct net *net)
{
	struct ctl_table *table;

	table = kmemdup(ipv6_icmp_table_template,
			sizeof(ipv6_icmp_table_template),
			GFP_KERNEL);

	if (table)
		table[0].data = &net->ipv6.sysctl.icmpv6_time;

	return table;
}
#endif