icmp.c 23.1 KB
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/*
 *	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
 */

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#define pr_fmt(fmt) "IPv6: " fmt

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#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>
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#include <linux/netfilter.h>
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#include <linux/slab.h>
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#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>
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#include <net/ping.h>
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#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>
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#include <net/xfrm.h>
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#include <net/inet_common.h>
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#include <net/dsfield.h>
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#include <net/l3mdev.h>
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#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.
 */
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static inline struct sock *icmpv6_sk(struct net *net)
{
	return net->ipv6.icmp_sk[smp_processor_id()];
}
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static void icmpv6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
		       u8 type, u8 code, int offset, __be32 info)
{
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	/* icmpv6_notify checks 8 bytes can be pulled, icmp6hdr is 8 bytes */
	struct icmp6hdr *icmp6 = (struct icmp6hdr *) (skb->data + offset);
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	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)
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		ip6_redirect(skb, net, skb->dev->ifindex, 0);
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	if (!(type & ICMPV6_INFOMSG_MASK))
		if (icmp6->icmp6_type == ICMPV6_ECHO_REQUEST)
			ping_err(skb, offset, info);
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}

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static int icmpv6_rcv(struct sk_buff *skb);
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static const struct inet6_protocol icmpv6_protocol = {
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	.handler	=	icmpv6_rcv,
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	.err_handler	=	icmpv6_err,
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	.flags		=	INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
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};

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

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	local_bh_disable();

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	sk = icmpv6_sk(net);
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	if (unlikely(!spin_trylock(&sk->sk_lock.slock))) {
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		/* 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();
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		return NULL;
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	}
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	return sk;
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}

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

/*
 * 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)
 */

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static bool is_ineligible(const struct sk_buff *skb)
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{
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	int ptr = (u8 *)(ipv6_hdr(skb) + 1) - skb->data;
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	int len = skb->len - ptr;
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	__u8 nexthdr = ipv6_hdr(skb)->nexthdr;
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	__be16 frag_off;
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	if (len < 0)
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		return true;
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	ptr = ipv6_skip_exthdr(skb, ptr, &nexthdr, &frag_off);
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	if (ptr < 0)
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		return false;
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	if (nexthdr == IPPROTO_ICMPV6) {
		u8 _type, *tp;
		tp = skb_header_pointer(skb,
			ptr+offsetof(struct icmp6hdr, icmp6_type),
			sizeof(_type), &_type);
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		if (!tp || !(*tp & ICMPV6_INFOMSG_MASK))
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			return true;
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	}
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	return false;
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}

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/*
 * Check the ICMP output rate limit
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 */
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static bool icmpv6_xrlim_allow(struct sock *sk, u8 type,
			       struct flowi6 *fl6)
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{
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	struct net *net = sock_net(sk);
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	struct dst_entry *dst;
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	bool res = false;
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	/* Informational messages are not limited. */
	if (type & ICMPV6_INFOMSG_MASK)
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		return true;
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	/* Do not limit pmtu discovery, it would break it. */
	if (type == ICMPV6_PKT_TOOBIG)
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		return true;
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	/*
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	 * Look up the output route.
	 * XXX: perhaps the expire for routing entries cloned by
	 * this lookup should be more aggressive (not longer than timeout).
	 */
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	dst = ip6_route_output(net, sk, fl6);
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	if (dst->error) {
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		IP6_INC_STATS(net, ip6_dst_idev(dst),
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			      IPSTATS_MIB_OUTNOROUTES);
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	} else if (dst->dev && (dst->dev->flags&IFF_LOOPBACK)) {
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		res = true;
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	} else {
		struct rt6_info *rt = (struct rt6_info *)dst;
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		int tmo = net->ipv6.sysctl.icmpv6_time;
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		/* Give more bandwidth to wider prefixes. */
		if (rt->rt6i_dst.plen < 128)
			tmo >>= ((128 - rt->rt6i_dst.plen)>>5);

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		if (icmp_global_allow()) {
			struct inet_peer *peer;

			peer = inet_getpeer_v6(net->ipv6.peers,
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					       &fl6->daddr, 1);
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			res = inet_peer_xrlim_allow(peer, tmo);
			if (peer)
				inet_putpeer(peer);
		}
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	}
	dst_release(dst);
	return res;
}

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

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

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

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

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

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

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

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

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

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

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#if IS_ENABLED(CONFIG_IPV6_MIP6)
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static void mip6_addr_swap(struct sk_buff *skb)
{
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	struct ipv6hdr *iph = ipv6_hdr(skb);
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	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)) {
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			hao = (struct ipv6_destopt_hao *)
					(skb_network_header(skb) + off);
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			tmp = iph->saddr;
			iph->saddr = hao->addr;
			hao->addr = tmp;
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		}
	}
}
#else
static inline void mip6_addr_swap(struct sk_buff *skb) {}
#endif

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

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

	/*
	 * We won't send icmp if the destination is known
	 * anycast.
	 */
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	if (ipv6_anycast_destination(dst, &fl6->daddr)) {
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		net_dbg_ratelimited("icmp6_send: acast source\n");
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		dst_release(dst);
		return ERR_PTR(-EINVAL);
	}

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

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

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

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

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

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

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/*
 *	Send an ICMP message in response to a packet in error
 */
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static void icmp6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info)
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{
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	struct net *net = dev_net(skb->dev);
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	struct inet6_dev *idev = NULL;
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	struct ipv6hdr *hdr = ipv6_hdr(skb);
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	struct sock *sk;
	struct ipv6_pinfo *np;
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	const struct in6_addr *saddr = NULL;
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	struct dst_entry *dst;
	struct icmp6hdr tmp_hdr;
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	struct flowi6 fl6;
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	struct icmpv6_msg msg;
	int iif = 0;
	int addr_type = 0;
	int len;
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	int hlimit;
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	int err = 0;
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	u32 mark = IP6_REPLY_MARK(net, skb->mark);
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	if ((u8 *)hdr < skb->head ||
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	    (skb_network_header(skb) + sizeof(*hdr)) > skb_tail_pointer(skb))
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		return;

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

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

	/*
	 *	Dest addr check
	 */

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

		saddr = NULL;
	}

	addr_type = ipv6_addr_type(&hdr->saddr);

	/*
	 *	Source addr check
	 */

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

	/*
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	 *	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.
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	 */
	if ((addr_type == IPV6_ADDR_ANY) || (addr_type & IPV6_ADDR_MULTICAST)) {
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		net_dbg_ratelimited("icmp6_send: addr_any/mcast source\n");
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		return;
	}

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

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	mip6_addr_swap(skb);

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	memset(&fl6, 0, sizeof(fl6));
	fl6.flowi6_proto = IPPROTO_ICMPV6;
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	fl6.daddr = hdr->saddr;
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	if (saddr)
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		fl6.saddr = *saddr;
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	fl6.flowi6_mark = mark;
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	fl6.flowi6_oif = iif;
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	fl6.fl6_icmp_type = type;
	fl6.fl6_icmp_code = code;
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	security_skb_classify_flow(skb, flowi6_to_flowi(&fl6));
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	sk = icmpv6_xmit_lock(net);
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	if (!sk)
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		return;
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	sk->sk_mark = mark;
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	np = inet6_sk(sk);
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	if (!icmpv6_xrlim_allow(sk, type, &fl6))
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		goto out;

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

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	if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr))
		fl6.flowi6_oif = np->mcast_oif;
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	else if (!fl6.flowi6_oif)
		fl6.flowi6_oif = np->ucast_oif;
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	if (!fl6.flowi6_oif)
		fl6.flowi6_oif = l3mdev_master_ifindex(skb->dev);

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	dst = icmpv6_route_lookup(net, skb, sk, &fl6);
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	if (IS_ERR(dst))
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		goto out;
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	hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst);
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	msg.skb = skb;
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	msg.offset = skb_network_offset(skb);
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	msg.type = type;
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	len = skb->len - msg.offset;
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	len = min_t(unsigned int, len, IPV6_MIN_MTU - sizeof(struct ipv6hdr) - sizeof(struct icmp6hdr));
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	if (len < 0) {
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		net_dbg_ratelimited("icmp: len problem\n");
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		goto out_dst_release;
	}

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	rcu_read_lock();
	idev = __in6_dev_get(skb->dev);
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	err = ip6_append_data(sk, icmpv6_getfrag, &msg,
			      len + sizeof(struct icmp6hdr),
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			      sizeof(struct icmp6hdr), hlimit,
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			      np->tclass, NULL, &fl6, (struct rt6_info *)dst,
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			      MSG_DONTWAIT, np->dontfrag);
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	if (err) {
529
		ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTERRORS);
L
Linus Torvalds 已提交
530
		ip6_flush_pending_frames(sk);
E
Eric Dumazet 已提交
531 532 533
	} else {
		err = icmpv6_push_pending_frames(sk, &fl6, &tmp_hdr,
						 len + sizeof(struct icmp6hdr));
L
Linus Torvalds 已提交
534
	}
E
Eric Dumazet 已提交
535
	rcu_read_unlock();
L
Linus Torvalds 已提交
536 537 538
out_dst_release:
	dst_release(dst);
out:
539
	icmpv6_xmit_unlock(sk);
L
Linus Torvalds 已提交
540
}
541 542 543 544 545 546 547 548

/* 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);
}
549

L
Linus Torvalds 已提交
550 551
static void icmpv6_echo_reply(struct sk_buff *skb)
{
552
	struct net *net = dev_net(skb->dev);
553
	struct sock *sk;
L
Linus Torvalds 已提交
554
	struct inet6_dev *idev;
555
	struct ipv6_pinfo *np;
556
	const struct in6_addr *saddr = NULL;
557
	struct icmp6hdr *icmph = icmp6_hdr(skb);
L
Linus Torvalds 已提交
558
	struct icmp6hdr tmp_hdr;
559
	struct flowi6 fl6;
L
Linus Torvalds 已提交
560 561 562 563
	struct icmpv6_msg msg;
	struct dst_entry *dst;
	int err = 0;
	int hlimit;
564
	u8 tclass;
565
	u32 mark = IP6_REPLY_MARK(net, skb->mark);
L
Linus Torvalds 已提交
566

567
	saddr = &ipv6_hdr(skb)->daddr;
L
Linus Torvalds 已提交
568

569
	if (!ipv6_unicast_destination(skb) &&
570
	    !(net->ipv6.sysctl.anycast_src_echo_reply &&
571
	      ipv6_anycast_destination(skb_dst(skb), saddr)))
L
Linus Torvalds 已提交
572 573 574 575 576
		saddr = NULL;

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

577 578
	memset(&fl6, 0, sizeof(fl6));
	fl6.flowi6_proto = IPPROTO_ICMPV6;
A
Alexey Dobriyan 已提交
579
	fl6.daddr = ipv6_hdr(skb)->saddr;
L
Linus Torvalds 已提交
580
	if (saddr)
A
Alexey Dobriyan 已提交
581
		fl6.saddr = *saddr;
D
David Ahern 已提交
582
	fl6.flowi6_oif = l3mdev_fib_oif(skb->dev);
583
	fl6.fl6_icmp_type = ICMPV6_ECHO_REPLY;
584
	fl6.flowi6_mark = mark;
585
	security_skb_classify_flow(skb, flowi6_to_flowi(&fl6));
L
Linus Torvalds 已提交
586

587
	sk = icmpv6_xmit_lock(net);
588
	if (!sk)
589
		return;
590
	sk->sk_mark = mark;
591
	np = inet6_sk(sk);
592

593 594
	if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr))
		fl6.flowi6_oif = np->mcast_oif;
595 596
	else if (!fl6.flowi6_oif)
		fl6.flowi6_oif = np->ucast_oif;
L
Linus Torvalds 已提交
597

598
	err = ip6_dst_lookup(net, sk, &dst, &fl6);
L
Linus Torvalds 已提交
599 600
	if (err)
		goto out;
601
	dst = xfrm_lookup(net, dst, flowi6_to_flowi(&fl6), sk, 0);
602
	if (IS_ERR(dst))
603
		goto out;
L
Linus Torvalds 已提交
604

605
	hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst);
L
Linus Torvalds 已提交
606

E
Eric Dumazet 已提交
607
	idev = __in6_dev_get(skb->dev);
L
Linus Torvalds 已提交
608 609 610

	msg.skb = skb;
	msg.offset = 0;
611
	msg.type = ICMPV6_ECHO_REPLY;
L
Linus Torvalds 已提交
612

613
	tclass = ipv6_get_dsfield(ipv6_hdr(skb));
L
Linus Torvalds 已提交
614
	err = ip6_append_data(sk, icmpv6_getfrag, &msg, skb->len + sizeof(struct icmp6hdr),
615
				sizeof(struct icmp6hdr), hlimit, tclass, NULL, &fl6,
616
				(struct rt6_info *)dst, MSG_DONTWAIT,
617
				np->dontfrag);
L
Linus Torvalds 已提交
618 619

	if (err) {
E
Eric Dumazet 已提交
620
		ICMP6_INC_STATS_BH(net, idev, ICMP6_MIB_OUTERRORS);
L
Linus Torvalds 已提交
621
		ip6_flush_pending_frames(sk);
E
Eric Dumazet 已提交
622 623 624
	} else {
		err = icmpv6_push_pending_frames(sk, &fl6, &tmp_hdr,
						 skb->len + sizeof(struct icmp6hdr));
L
Linus Torvalds 已提交
625 626
	}
	dst_release(dst);
627
out:
628
	icmpv6_xmit_unlock(sk);
L
Linus Torvalds 已提交
629 630
}

631
void icmpv6_notify(struct sk_buff *skb, u8 type, u8 code, __be32 info)
L
Linus Torvalds 已提交
632
{
633
	const struct inet6_protocol *ipprot;
L
Linus Torvalds 已提交
634
	int inner_offset;
635
	__be16 frag_off;
636
	u8 nexthdr;
637
	struct net *net = dev_net(skb->dev);
L
Linus Torvalds 已提交
638 639

	if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
640
		goto out;
L
Linus Torvalds 已提交
641 642 643 644

	nexthdr = ((struct ipv6hdr *)skb->data)->nexthdr;
	if (ipv6_ext_hdr(nexthdr)) {
		/* now skip over extension headers */
645 646
		inner_offset = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr),
						&nexthdr, &frag_off);
647
		if (inner_offset < 0)
648
			goto out;
L
Linus Torvalds 已提交
649 650 651 652 653 654
	} else {
		inner_offset = sizeof(struct ipv6hdr);
	}

	/* Checkin header including 8 bytes of inner protocol header. */
	if (!pskb_may_pull(skb, inner_offset+8))
655
		goto out;
L
Linus Torvalds 已提交
656 657 658 659 660 661 662 663

	/* 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)
	 */

664
	ipprot = rcu_dereference(inet6_protos[nexthdr]);
L
Linus Torvalds 已提交
665 666 667
	if (ipprot && ipprot->err_handler)
		ipprot->err_handler(skb, NULL, type, code, inner_offset, info);

668
	raw6_icmp_error(skb, nexthdr, type, code, inner_offset, info);
669 670 671 672
	return;

out:
	ICMP6_INC_STATS_BH(net, __in6_dev_get(skb->dev), ICMP6_MIB_INERRORS);
L
Linus Torvalds 已提交
673
}
674

L
Linus Torvalds 已提交
675 676 677 678
/*
 *	Handle icmp messages
 */

679
static int icmpv6_rcv(struct sk_buff *skb)
L
Linus Torvalds 已提交
680 681 682
{
	struct net_device *dev = skb->dev;
	struct inet6_dev *idev = __in6_dev_get(dev);
683
	const struct in6_addr *saddr, *daddr;
L
Linus Torvalds 已提交
684
	struct icmp6hdr *hdr;
685
	u8 type;
686
	bool success = false;
L
Linus Torvalds 已提交
687

688
	if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
689
		struct sec_path *sp = skb_sec_path(skb);
690 691
		int nh;

692
		if (!(sp && sp->xvec[sp->len - 1]->props.flags &
693 694 695
				 XFRM_STATE_ICMP))
			goto drop_no_count;

696
		if (!pskb_may_pull(skb, sizeof(*hdr) + sizeof(struct ipv6hdr)))
697 698 699 700 701 702 703 704 705 706 707
			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);
	}

708
	ICMP6_INC_STATS_BH(dev_net(dev), idev, ICMP6_MIB_INMSGS);
L
Linus Torvalds 已提交
709

710 711
	saddr = &ipv6_hdr(skb)->saddr;
	daddr = &ipv6_hdr(skb)->daddr;
L
Linus Torvalds 已提交
712

T
Tom Herbert 已提交
713
	if (skb_checksum_validate(skb, IPPROTO_ICMPV6, ip6_compute_pseudo)) {
714 715
		net_dbg_ratelimited("ICMPv6 checksum failed [%pI6c > %pI6c]\n",
				    saddr, daddr);
T
Tom Herbert 已提交
716
		goto csum_error;
L
Linus Torvalds 已提交
717 718
	}

719 720
	if (!pskb_pull(skb, sizeof(*hdr)))
		goto discard_it;
L
Linus Torvalds 已提交
721

722
	hdr = icmp6_hdr(skb);
L
Linus Torvalds 已提交
723 724 725

	type = hdr->icmp6_type;

726
	ICMP6MSGIN_INC_STATS_BH(dev_net(dev), idev, type);
L
Linus Torvalds 已提交
727 728 729 730 731 732 733

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

	case ICMPV6_ECHO_REPLY:
734
		success = ping_rcv(skb);
L
Linus Torvalds 已提交
735 736 737 738 739 740 741 742 743 744
		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;
745
		hdr = icmp6_hdr(skb);
L
Linus Torvalds 已提交
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

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

788
		net_dbg_ratelimited("icmpv6: msg of unknown type\n");
789

790 791 792
		/*
		 * error of unknown type.
		 * must pass to upper level
L
Linus Torvalds 已提交
793 794 795
		 */

		icmpv6_notify(skb, type, hdr->icmp6_code, hdr->icmp6_mtu);
796 797
	}

798 799 800 801 802 803 804 805
	/* until the v6 path can be better sorted assume failure and
	 * preserve the status quo behaviour for the rest of the paths to here
	 */
	if (success)
		consume_skb(skb);
	else
		kfree_skb(skb);

L
Linus Torvalds 已提交
806 807
	return 0;

808 809
csum_error:
	ICMP6_INC_STATS_BH(dev_net(dev), idev, ICMP6_MIB_CSUMERRORS);
L
Linus Torvalds 已提交
810
discard_it:
811
	ICMP6_INC_STATS_BH(dev_net(dev), idev, ICMP6_MIB_INERRORS);
812
drop_no_count:
L
Linus Torvalds 已提交
813 814 815 816
	kfree_skb(skb);
	return 0;
}

817
void icmpv6_flow_init(struct sock *sk, struct flowi6 *fl6,
818 819 820 821 822
		      u8 type,
		      const struct in6_addr *saddr,
		      const struct in6_addr *daddr,
		      int oif)
{
823
	memset(fl6, 0, sizeof(*fl6));
A
Alexey Dobriyan 已提交
824 825
	fl6->saddr = *saddr;
	fl6->daddr = *daddr;
826
	fl6->flowi6_proto	= IPPROTO_ICMPV6;
827 828
	fl6->fl6_icmp_type	= type;
	fl6->fl6_icmp_code	= 0;
829 830
	fl6->flowi6_oif		= oif;
	security_sk_classify_flow(sk, flowi6_to_flowi(fl6));
831 832
}

833
/*
834
 * Special lock-class for __icmpv6_sk:
835 836 837
 */
static struct lock_class_key icmpv6_socket_sk_dst_lock_key;

838
static int __net_init icmpv6_sk_init(struct net *net)
L
Linus Torvalds 已提交
839 840 841 842
{
	struct sock *sk;
	int err, i, j;

843 844
	net->ipv6.icmp_sk =
		kzalloc(nr_cpu_ids * sizeof(struct sock *), GFP_KERNEL);
845
	if (!net->ipv6.icmp_sk)
846 847
		return -ENOMEM;

848
	for_each_possible_cpu(i) {
849 850
		err = inet_ctl_sock_create(&sk, PF_INET6,
					   SOCK_RAW, IPPROTO_ICMPV6, net);
L
Linus Torvalds 已提交
851
		if (err < 0) {
852
			pr_err("Failed to initialize the ICMP6 control socket (err %d)\n",
L
Linus Torvalds 已提交
853 854 855 856
			       err);
			goto fail;
		}

857
		net->ipv6.icmp_sk[i] = sk;
858

859 860 861
		/*
		 * Split off their lock-class, because sk->sk_dst_lock
		 * gets used from softirqs, which is safe for
862
		 * __icmpv6_sk (because those never get directly used
863 864 865 866
		 * via userspace syscalls), but unsafe for normal sockets.
		 */
		lockdep_set_class(&sk->sk_dst_lock,
				  &icmpv6_socket_sk_dst_lock_key);
L
Linus Torvalds 已提交
867 868 869 870

		/* Enough space for 2 64K ICMP packets, including
		 * sk_buff struct overhead.
		 */
E
Eric Dumazet 已提交
871
		sk->sk_sndbuf = 2 * SKB_TRUESIZE(64 * 1024);
L
Linus Torvalds 已提交
872 873 874 875
	}
	return 0;

 fail:
876
	for (j = 0; j < i; j++)
877
		inet_ctl_sock_destroy(net->ipv6.icmp_sk[j]);
878
	kfree(net->ipv6.icmp_sk);
L
Linus Torvalds 已提交
879 880 881
	return err;
}

882
static void __net_exit icmpv6_sk_exit(struct net *net)
L
Linus Torvalds 已提交
883 884 885
{
	int i;

886
	for_each_possible_cpu(i) {
887
		inet_ctl_sock_destroy(net->ipv6.icmp_sk[i]);
L
Linus Torvalds 已提交
888
	}
889 890 891
	kfree(net->ipv6.icmp_sk);
}

892
static struct pernet_operations icmpv6_sk_ops = {
893 894
	.init = icmpv6_sk_init,
	.exit = icmpv6_sk_exit,
895 896 897 898 899 900 901 902 903 904 905 906 907
};

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;
908 909 910 911

	err = inet6_register_icmp_sender(icmp6_send);
	if (err)
		goto sender_reg_err;
912 913
	return 0;

914 915
sender_reg_err:
	inet6_del_protocol(&icmpv6_protocol, IPPROTO_ICMPV6);
916
fail:
917
	pr_err("Failed to register ICMP6 protocol\n");
918 919 920 921
	unregister_pernet_subsys(&icmpv6_sk_ops);
	return err;
}

922
void icmpv6_cleanup(void)
923
{
924
	inet6_unregister_icmp_sender(icmp6_send);
925
	unregister_pernet_subsys(&icmpv6_sk_ops);
L
Linus Torvalds 已提交
926 927 928
	inet6_del_protocol(&icmpv6_protocol, IPPROTO_ICMPV6);
}

929

930
static const struct icmp6_err {
L
Linus Torvalds 已提交
931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953
	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,
	},
954 955 956 957 958 959 960 961
	{	/* POLICY_FAIL */
		.err	= EACCES,
		.fatal	= 1,
	},
	{	/* REJECT_ROUTE	*/
		.err	= EACCES,
		.fatal	= 1,
	},
L
Linus Torvalds 已提交
962 963
};

964
int icmpv6_err_convert(u8 type, u8 code, int *err)
L
Linus Torvalds 已提交
965 966 967 968 969 970 971 972
{
	int fatal = 0;

	*err = EPROTO;

	switch (type) {
	case ICMPV6_DEST_UNREACH:
		fatal = 1;
973
		if (code < ARRAY_SIZE(tab_unreach)) {
L
Linus Torvalds 已提交
974 975 976 977 978 979 980 981
			*err  = tab_unreach[code].err;
			fatal = tab_unreach[code].fatal;
		}
		break;

	case ICMPV6_PKT_TOOBIG:
		*err = EMSGSIZE;
		break;
982

L
Linus Torvalds 已提交
983 984 985 986 987 988 989 990
	case ICMPV6_PARAMPROB:
		*err = EPROTO;
		fatal = 1;
		break;

	case ICMPV6_TIME_EXCEED:
		*err = EHOSTUNREACH;
		break;
991
	}
L
Linus Torvalds 已提交
992 993 994

	return fatal;
}
995 996
EXPORT_SYMBOL(icmpv6_err_convert);

L
Linus Torvalds 已提交
997
#ifdef CONFIG_SYSCTL
S
stephen hemminger 已提交
998
static struct ctl_table ipv6_icmp_table_template[] = {
L
Linus Torvalds 已提交
999 1000
	{
		.procname	= "ratelimit",
1001
		.data		= &init_net.ipv6.sysctl.icmpv6_time,
L
Linus Torvalds 已提交
1002 1003
		.maxlen		= sizeof(int),
		.mode		= 0644,
A
Alexey Dobriyan 已提交
1004
		.proc_handler	= proc_dointvec_ms_jiffies,
L
Linus Torvalds 已提交
1005
	},
1006
	{ },
L
Linus Torvalds 已提交
1007
};
1008

1009
struct ctl_table * __net_init ipv6_icmp_sysctl_init(struct net *net)
1010 1011 1012 1013 1014 1015
{
	struct ctl_table *table;

	table = kmemdup(ipv6_icmp_table_template,
			sizeof(ipv6_icmp_table_template),
			GFP_KERNEL);
1016

1017
	if (table)
1018 1019
		table[0].data = &net->ipv6.sysctl.icmpv6_time;

1020 1021
	return table;
}
L
Linus Torvalds 已提交
1022
#endif