[linux.git] / net / ipv6 / ip6_input.c

/*
 *	IPv6 input
 *	Linux INET6 implementation
 *
 *	Authors:
 *	Pedro Roque		<[email protected]>
 *	Ian P. Morris		<[email protected]>
 *
 *	Based in linux/net/ipv4/ip_input.c
 *
 *	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
 *
 * 	Mitsuru KANDA @USAGI and
 * 	YOSHIFUJI Hideaki @USAGI: Remove ipv6_parse_exthdrs().
 */

#include <linux/errno.h>
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/sockios.h>
#include <linux/net.h>
#include <linux/netdevice.h>
#include <linux/in6.h>
#include <linux/icmpv6.h>
#include <linux/mroute6.h>
#include <linux/slab.h>

#include <linux/netfilter.h>
#include <linux/netfilter_ipv6.h>

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

#include <net/ipv6.h>
#include <net/protocol.h>
#include <net/transp_v6.h>
#include <net/rawv6.h>
#include <net/ndisc.h>
#include <net/ip6_route.h>
#include <net/addrconf.h>
#include <net/xfrm.h>


int ip6_rcv_finish(struct sk_buff *skb)
{
	if (sysctl_ip_early_demux && !skb_dst(skb)) {
		const struct inet6_protocol *ipprot;

		ipprot = rcu_dereference(inet6_protos[ipv6_hdr(skb)->nexthdr]);
		if (ipprot && ipprot->early_demux)
			ipprot->early_demux(skb);
	}
	if (!skb_dst(skb))
		ip6_route_input(skb);

	return dst_input(skb);
}

int ipv6_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, struct net_device *orig_dev)
{
	const struct ipv6hdr *hdr;
	u32 		pkt_len;
	struct inet6_dev *idev;
	struct net *net = dev_net(skb->dev);

	if (skb->pkt_type == PACKET_OTHERHOST) {
		kfree_skb(skb);
		return NET_RX_DROP;
	}

	rcu_read_lock();

	idev = __in6_dev_get(skb->dev);

	IP6_UPD_PO_STATS_BH(net, idev, IPSTATS_MIB_IN, skb->len);

	if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL ||
	    !idev || unlikely(idev->cnf.disable_ipv6)) {
		IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INDISCARDS);
		goto drop;
	}

	memset(IP6CB(skb), 0, sizeof(struct inet6_skb_parm));

	/*
	 * Store incoming device index. When the packet will
	 * be queued, we cannot refer to skb->dev anymore.
	 *
	 * BTW, when we send a packet for our own local address on a
	 * non-loopback interface (e.g. ethX), it is being delivered
	 * via the loopback interface (lo) here; skb->dev = loopback_dev.
	 * It, however, should be considered as if it is being
	 * arrived via the sending interface (ethX), because of the
	 * nature of scoping architecture. --yoshfuji
	 */
	IP6CB(skb)->iif = skb_dst(skb) ? ip6_dst_idev(skb_dst(skb))->dev->ifindex : dev->ifindex;

	if (unlikely(!pskb_may_pull(skb, sizeof(*hdr))))
		goto err;

	hdr = ipv6_hdr(skb);

	if (hdr->version != 6)
		goto err;

	/*
	 * RFC4291 2.5.3
	 * A packet received on an interface with a destination address
	 * of loopback must be dropped.
	 */
	if (!(dev->flags & IFF_LOOPBACK) &&
	    ipv6_addr_loopback(&hdr->daddr))
		goto err;

	/*
	 * RFC4291 2.7
	 * Multicast addresses must not be used as source addresses in IPv6
	 * packets or appear in any Routing header.
	 */
	if (ipv6_addr_is_multicast(&hdr->saddr))
		goto err;

	skb->transport_header = skb->network_header + sizeof(*hdr);
	IP6CB(skb)->nhoff = offsetof(struct ipv6hdr, nexthdr);

	pkt_len = ntohs(hdr->payload_len);

	/* pkt_len may be zero if Jumbo payload option is present */
	if (pkt_len || hdr->nexthdr != NEXTHDR_HOP) {
		if (pkt_len + sizeof(struct ipv6hdr) > skb->len) {
			IP6_INC_STATS_BH(net,
					 idev, IPSTATS_MIB_INTRUNCATEDPKTS);
			goto drop;
		}
		if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr))) {
			IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INHDRERRORS);
			goto drop;
		}
		hdr = ipv6_hdr(skb);
	}

	if (hdr->nexthdr == NEXTHDR_HOP) {
		if (ipv6_parse_hopopts(skb) < 0) {
			IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INHDRERRORS);
			rcu_read_unlock();
			return NET_RX_DROP;
		}
	}

	rcu_read_unlock();

	/* Must drop socket now because of tproxy. */
	skb_orphan(skb);

	return NF_HOOK(NFPROTO_IPV6, NF_INET_PRE_ROUTING, skb, dev, NULL,
		       ip6_rcv_finish);
err:
	IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INHDRERRORS);
drop:
	rcu_read_unlock();
	kfree_skb(skb);
	return NET_RX_DROP;
}

/*
 *	Deliver the packet to the host
 */


static int ip6_input_finish(struct sk_buff *skb)
{
	struct net *net = dev_net(skb_dst(skb)->dev);
	const struct inet6_protocol *ipprot;
	struct inet6_dev *idev;
	unsigned int nhoff;
	int nexthdr;
	bool raw;

	/*
	 *	Parse extension headers
	 */

	rcu_read_lock();
resubmit:
	idev = ip6_dst_idev(skb_dst(skb));
	if (!pskb_pull(skb, skb_transport_offset(skb)))
		goto discard;
	nhoff = IP6CB(skb)->nhoff;
	nexthdr = skb_network_header(skb)[nhoff];

	raw = raw6_local_deliver(skb, nexthdr);
	if ((ipprot = rcu_dereference(inet6_protos[nexthdr])) != NULL) {
		int ret;

		if (ipprot->flags & INET6_PROTO_FINAL) {
			const struct ipv6hdr *hdr;

			/* Free reference early: we don't need it any more,
			   and it may hold ip_conntrack module loaded
			   indefinitely. */
			nf_reset(skb);

			skb_postpull_rcsum(skb, skb_network_header(skb),
					   skb_network_header_len(skb));
			hdr = ipv6_hdr(skb);
			if (ipv6_addr_is_multicast(&hdr->daddr) &&
			    !ipv6_chk_mcast_addr(skb->dev, &hdr->daddr,
			    &hdr->saddr) &&
			    !ipv6_is_mld(skb, nexthdr))
				goto discard;
		}
		if (!(ipprot->flags & INET6_PROTO_NOPOLICY) &&
		    !xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
			goto discard;

		ret = ipprot->handler(skb);
		if (ret > 0)
			goto resubmit;
		else if (ret == 0)
			IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INDELIVERS);
	} else {
		if (!raw) {
			if (xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
				IP6_INC_STATS_BH(net, idev,
						 IPSTATS_MIB_INUNKNOWNPROTOS);
				icmpv6_send(skb, ICMPV6_PARAMPROB,
					    ICMPV6_UNK_NEXTHDR, nhoff);
			}
		} else
			IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INDELIVERS);
		kfree_skb(skb);
	}
	rcu_read_unlock();
	return 0;

discard:
	IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INDISCARDS);
	rcu_read_unlock();
	kfree_skb(skb);
	return 0;
}


int ip6_input(struct sk_buff *skb)
{
	return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_IN, skb, skb->dev, NULL,
		       ip6_input_finish);
}

int ip6_mc_input(struct sk_buff *skb)
{
	const struct ipv6hdr *hdr;
	bool deliver;

	IP6_UPD_PO_STATS_BH(dev_net(skb_dst(skb)->dev),
			 ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_INMCAST,
			 skb->len);

	hdr = ipv6_hdr(skb);
	deliver = ipv6_chk_mcast_addr(skb->dev, &hdr->daddr, NULL);

#ifdef CONFIG_IPV6_MROUTE
	/*
	 *      IPv6 multicast router mode is now supported ;)
	 */
	if (dev_net(skb->dev)->ipv6.devconf_all->mc_forwarding &&
	    !(ipv6_addr_type(&hdr->daddr) & IPV6_ADDR_LINKLOCAL) &&
	    likely(!(IP6CB(skb)->flags & IP6SKB_FORWARDED))) {
		/*
		 * Okay, we try to forward - split and duplicate
		 * packets.
		 */
		struct sk_buff *skb2;
		struct inet6_skb_parm *opt = IP6CB(skb);

		/* Check for MLD */
		if (unlikely(opt->ra)) {
			/* Check if this is a mld message */
			u8 *ptr = skb_network_header(skb) + opt->ra;
			struct icmp6hdr *icmp6;
			u8 nexthdr = hdr->nexthdr;
			__be16 frag_off;
			int offset;

			/* Check if the value of Router Alert
			 * is for MLD (0x0000).
			 */
			if ((ptr[2] | ptr[3]) == 0) {
				deliver = false;

				if (!ipv6_ext_hdr(nexthdr)) {
					/* BUG */
					goto out;
				}
				offset = ipv6_skip_exthdr(skb, sizeof(*hdr),
							  &nexthdr, &frag_off);
				if (offset < 0)
					goto out;

				if (nexthdr != IPPROTO_ICMPV6)
					goto out;

				if (!pskb_may_pull(skb, (skb_network_header(skb) +
						   offset + 1 - skb->data)))
					goto out;

				icmp6 = (struct icmp6hdr *)(skb_network_header(skb) + offset);

				switch (icmp6->icmp6_type) {
				case ICMPV6_MGM_QUERY:
				case ICMPV6_MGM_REPORT:
				case ICMPV6_MGM_REDUCTION:
				case ICMPV6_MLD2_REPORT:
					deliver = true;
					break;
				}
				goto out;
			}
			/* unknown RA - process it normally */
		}

		if (deliver)
			skb2 = skb_clone(skb, GFP_ATOMIC);
		else {
			skb2 = skb;
			skb = NULL;
		}

		if (skb2) {
			ip6_mr_input(skb2);
		}
	}
out:
#endif
	if (likely(deliver))
		ip6_input(skb);
	else {
		/* discard */
		kfree_skb(skb);
	}

	return 0;
}
Commit	Line	Data
1da177e4 LT	1	/*
1da177e4 LT	2	* IPv6 input
1ab1457c	3	* Linux INET6 implementation
1da177e4 LT	4	*
	5	* Authors:
	6	* Pedro Roque <[email protected]>
	7	* Ian P. Morris <[email protected]>
	8	*
1da177e4 LT	9	* Based in linux/net/ipv4/ip_input.c
	10	*
	11	* This program is free software; you can redistribute it and/or
	12	* modify it under the terms of the GNU General Public License
	13	* as published by the Free Software Foundation; either version
	14	* 2 of the License, or (at your option) any later version.
	15	*/
	16	/* Changes
	17	*
	18	* Mitsuru KANDA @USAGI and
	19	* YOSHIFUJI Hideaki @USAGI: Remove ipv6_parse_exthdrs().
	20	*/
	21
	22	#include <linux/errno.h>
	23	#include <linux/types.h>
	24	#include <linux/socket.h>
	25	#include <linux/sockios.h>
1da177e4 LT	26	#include <linux/net.h>
	27	#include <linux/netdevice.h>
	28	#include <linux/in6.h>
	29	#include <linux/icmpv6.h>
7bc570c8	30	#include <linux/mroute6.h>
5a0e3ad6	31	#include <linux/slab.h>
1da177e4 LT	32
	33	#include <linux/netfilter.h>
	34	#include <linux/netfilter_ipv6.h>
	35
	36	#include <net/sock.h>
	37	#include <net/snmp.h>
	38
	39	#include <net/ipv6.h>
	40	#include <net/protocol.h>
	41	#include <net/transp_v6.h>
	42	#include <net/rawv6.h>
	43	#include <net/ndisc.h>
	44	#include <net/ip6_route.h>
	45	#include <net/addrconf.h>
	46	#include <net/xfrm.h>
	47
	48
	49
c7109986	50	int ip6_rcv_finish(struct sk_buff *skb)
1da177e4	51	{
c7109986 ED	52	if (sysctl_ip_early_demux && !skb_dst(skb)) {
	53	const struct inet6_protocol *ipprot;
	54
c7109986 ED	55	ipprot = rcu_dereference(inet6_protos[ipv6_hdr(skb)->nexthdr]);
	56	if (ipprot && ipprot->early_demux)
	57	ipprot->early_demux(skb);
c7109986 ED	58	}
c7109986 ED	59	if (!skb_dst(skb))
1da177e4 LT	60	ip6_route_input(skb);
	61
	62	return dst_input(skb);
	63	}
	64
f2ccd8fa	65	int ipv6_rcv(struct sk_buff skb, struct net_device dev, struct packet_type pt, struct net_device orig_dev)
1da177e4	66	{
b71d1d42	67	const struct ipv6hdr *hdr;
1da177e4	68	u32 pkt_len;
a11d206d	69	struct inet6_dev *idev;
483a47d2	70	struct net *net = dev_net(skb->dev);
1da177e4	71
a11d206d YH	72	if (skb->pkt_type == PACKET_OTHERHOST) {
a11d206d YH	73	kfree_skb(skb);
5c91face	74	return NET_RX_DROP;
a11d206d YH	75	}
	76
	77	rcu_read_lock();
1da177e4	78
a11d206d YH	79	idev = __in6_dev_get(skb->dev);
a11d206d YH	80
edf391ff	81	IP6_UPD_PO_STATS_BH(net, idev, IPSTATS_MIB_IN, skb->len);
1da177e4	82
778d80be YH	83	if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL \|\|
778d80be YH	84	!idev \|\| unlikely(idev->cnf.disable_ipv6)) {
483a47d2	85	IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INDISCARDS);
71f6f6df	86	goto drop;
1da177e4 LT	87	}
1da177e4 LT	88
6b7fdc3a GC	89	memset(IP6CB(skb), 0, sizeof(struct inet6_skb_parm));
6b7fdc3a GC	90
1da177e4 LT	91	/*
	92	* Store incoming device index. When the packet will
	93	* be queued, we cannot refer to skb->dev anymore.
	94	*
	95	* BTW, when we send a packet for our own local address on a
	96	* non-loopback interface (e.g. ethX), it is being delivered
de3cb747	97	* via the loopback interface (lo) here; skb->dev = loopback_dev.
1da177e4 LT	98	* It, however, should be considered as if it is being
	99	* arrived via the sending interface (ethX), because of the
	100	* nature of scoping architecture. --yoshfuji
	101	*/
adf30907	102	IP6CB(skb)->iif = skb_dst(skb) ? ip6_dst_idev(skb_dst(skb))->dev->ifindex : dev->ifindex;
1da177e4	103
2889139a	104	if (unlikely(!pskb_may_pull(skb, sizeof(*hdr))))
1da177e4 LT	105	goto err;
1da177e4 LT	106
0660e03f	107	hdr = ipv6_hdr(skb);
1da177e4 LT	108
	109	if (hdr->version != 6)
	110	goto err;
	111
f630e43a YH	112	/*
	113	* RFC4291 2.5.3
	114	* A packet received on an interface with a destination address
	115	* of loopback must be dropped.
	116	*/
	117	if (!(dev->flags & IFF_LOOPBACK) &&
	118	ipv6_addr_loopback(&hdr->daddr))
	119	goto err;
	120
c457338d BH	121	/*
	122	* RFC4291 2.7
	123	* Multicast addresses must not be used as source addresses in IPv6
	124	* packets or appear in any Routing header.
	125	*/
	126	if (ipv6_addr_is_multicast(&hdr->saddr))
	127	goto err;
	128
b0e380b1	129	skb->transport_header = skb->network_header + sizeof(*hdr);
951dbc8a PM	130	IP6CB(skb)->nhoff = offsetof(struct ipv6hdr, nexthdr);
951dbc8a PM	131
1da177e4 LT	132	pkt_len = ntohs(hdr->payload_len);
	133
	134	/* pkt_len may be zero if Jumbo payload option is present */
	135	if (pkt_len \|\| hdr->nexthdr != NEXTHDR_HOP) {
60e5c166	136	if (pkt_len + sizeof(struct ipv6hdr) > skb->len) {
483a47d2 DL	137	IP6_INC_STATS_BH(net,
483a47d2 DL	138	idev, IPSTATS_MIB_INTRUNCATEDPKTS);
60e5c166 MC	139	goto drop;
60e5c166 MC	140	}
1da177e4	141	if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr))) {
483a47d2	142	IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INHDRERRORS);
1da177e4 LT	143	goto drop;
1da177e4 LT	144	}
0660e03f	145	hdr = ipv6_hdr(skb);
1da177e4 LT	146	}
	147
	148	if (hdr->nexthdr == NEXTHDR_HOP) {
e5bbef20	149	if (ipv6_parse_hopopts(skb) < 0) {
483a47d2	150	IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INHDRERRORS);
a11d206d	151	rcu_read_unlock();
5c91face	152	return NET_RX_DROP;
1da177e4	153	}
1da177e4 LT	154	}
1da177e4 LT	155
a11d206d YH	156	rcu_read_unlock();
a11d206d YH	157
71f9dacd HX	158	/* Must drop socket now because of tproxy. */
	159	skb_orphan(skb);
	160
b2e0b385	161	return NF_HOOK(NFPROTO_IPV6, NF_INET_PRE_ROUTING, skb, dev, NULL,
6e23ae2a	162	ip6_rcv_finish);
1da177e4	163	err:
483a47d2	164	IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INHDRERRORS);
1da177e4	165	drop:
a11d206d	166	rcu_read_unlock();
1da177e4	167	kfree_skb(skb);
5c91face	168	return NET_RX_DROP;
1da177e4 LT	169	}
	170
	171	/*
	172	* Deliver the packet to the host
	173	*/
	174
	175
ad643a79	176	static int ip6_input_finish(struct sk_buff *skb)
1da177e4	177	{
f9242b6b	178	struct net *net = dev_net(skb_dst(skb)->dev);
41135cc8	179	const struct inet6_protocol *ipprot;
f9242b6b	180	struct inet6_dev *idev;
1da177e4	181	unsigned int nhoff;
a50feda5 ED	182	int nexthdr;
a50feda5 ED	183	bool raw;
1da177e4	184
1da177e4 LT	185	/*
	186	* Parse extension headers
	187	*/
	188
1da177e4 LT	189	rcu_read_lock();
1da177e4 LT	190	resubmit:
adf30907	191	idev = ip6_dst_idev(skb_dst(skb));
ea2ae17d	192	if (!pskb_pull(skb, skb_transport_offset(skb)))
1da177e4	193	goto discard;
951dbc8a	194	nhoff = IP6CB(skb)->nhoff;
d56f90a7	195	nexthdr = skb_network_header(skb)[nhoff];
1da177e4	196
69d6da0b	197	raw = raw6_local_deliver(skb, nexthdr);
f9242b6b	198	if ((ipprot = rcu_dereference(inet6_protos[nexthdr])) != NULL) {
1da177e4	199	int ret;
1ab1457c	200
1da177e4	201	if (ipprot->flags & INET6_PROTO_FINAL) {
b71d1d42	202	const struct ipv6hdr *hdr;
1da177e4	203
9fb9cbb1 YK	204	/* Free reference early: we don't need it any more,
	205	and it may hold ip_conntrack module loaded
	206	indefinitely. */
	207	nf_reset(skb);
	208
d56f90a7	209	skb_postpull_rcsum(skb, skb_network_header(skb),
cfe1fc77	210	skb_network_header_len(skb));
0660e03f	211	hdr = ipv6_hdr(skb);
1da177e4 LT	212	if (ipv6_addr_is_multicast(&hdr->daddr) &&
	213	!ipv6_chk_mcast_addr(skb->dev, &hdr->daddr,
	214	&hdr->saddr) &&
	215	!ipv6_is_mld(skb, nexthdr))
	216	goto discard;
	217	}
	218	if (!(ipprot->flags & INET6_PROTO_NOPOLICY) &&
1ab1457c	219	!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
1da177e4	220	goto discard;
1ab1457c	221
e5bbef20	222	ret = ipprot->handler(skb);
1da177e4 LT	223	if (ret > 0)
	224	goto resubmit;
	225	else if (ret == 0)
483a47d2	226	IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INDELIVERS);
1da177e4	227	} else {
69d6da0b	228	if (!raw) {
1da177e4	229	if (xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
483a47d2 DL	230	IP6_INC_STATS_BH(net, idev,
483a47d2 DL	231	IPSTATS_MIB_INUNKNOWNPROTOS);
fad87aca	232	icmpv6_send(skb, ICMPV6_PARAMPROB,
3ffe533c	233	ICMPV6_UNK_NEXTHDR, nhoff);
1da177e4	234	}
fad87aca	235	} else
483a47d2	236	IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INDELIVERS);
fad87aca	237	kfree_skb(skb);
1da177e4 LT	238	}
	239	rcu_read_unlock();
	240	return 0;
	241
	242	discard:
483a47d2	243	IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INDISCARDS);
1da177e4 LT	244	rcu_read_unlock();
	245	kfree_skb(skb);
	246	return 0;
	247	}
	248
	249
	250	int ip6_input(struct sk_buff *skb)
	251	{
b2e0b385	252	return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_IN, skb, skb->dev, NULL,
6e23ae2a	253	ip6_input_finish);
1da177e4 LT	254	}
	255
	256	int ip6_mc_input(struct sk_buff *skb)
	257	{
b71d1d42	258	const struct ipv6hdr *hdr;
a50feda5	259	bool deliver;
1da177e4	260
adf30907 ED	261	IP6_UPD_PO_STATS_BH(dev_net(skb_dst(skb)->dev),
adf30907 ED	262	ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_INMCAST,
edf391ff	263	skb->len);
1da177e4	264
0660e03f	265	hdr = ipv6_hdr(skb);
4c7966b8	266	deliver = ipv6_chk_mcast_addr(skb->dev, &hdr->daddr, NULL);
1da177e4	267
7bc570c8	268	#ifdef CONFIG_IPV6_MROUTE
1da177e4	269	/*
7bc570c8	270	* IPv6 multicast router mode is now supported ;)
1da177e4	271	*/
53b7997f	272	if (dev_net(skb->dev)->ipv6.devconf_all->mc_forwarding &&
1d6e55f1	273	!(ipv6_addr_type(&hdr->daddr) & IPV6_ADDR_LINKLOCAL) &&
7bc570c8 YH	274	likely(!(IP6CB(skb)->flags & IP6SKB_FORWARDED))) {
	275	/*
	276	* Okay, we try to forward - split and duplicate
	277	* packets.
	278	*/
	279	struct sk_buff *skb2;
	280	struct inet6_skb_parm *opt = IP6CB(skb);
	281
	282	/* Check for MLD */
	283	if (unlikely(opt->ra)) {
	284	/* Check if this is a mld message */
	285	u8 *ptr = skb_network_header(skb) + opt->ra;
	286	struct icmp6hdr *icmp6;
	287	u8 nexthdr = hdr->nexthdr;
75f2811c	288	__be16 frag_off;
7bc570c8 YH	289	int offset;
	290
	291	/* Check if the value of Router Alert
	292	* is for MLD (0x0000).
	293	*/
	294	if ((ptr[2] \| ptr[3]) == 0) {
a50feda5	295	deliver = false;
aba6096b	296
7bc570c8 YH	297	if (!ipv6_ext_hdr(nexthdr)) {
7bc570c8 YH	298	/* BUG */
aba6096b	299	goto out;
7bc570c8 YH	300	}
7bc570c8 YH	301	offset = ipv6_skip_exthdr(skb, sizeof(*hdr),
75f2811c	302	&nexthdr, &frag_off);
7bc570c8	303	if (offset < 0)
aba6096b	304	goto out;
7bc570c8 YH	305
7bc570c8 YH	306	if (nexthdr != IPPROTO_ICMPV6)
aba6096b	307	goto out;
7bc570c8 YH	308
	309	if (!pskb_may_pull(skb, (skb_network_header(skb) +
	310	offset + 1 - skb->data)))
aba6096b	311	goto out;
7bc570c8 YH	312
	313	icmp6 = (struct icmp6hdr *)(skb_network_header(skb) + offset);
	314
	315	switch (icmp6->icmp6_type) {
	316	case ICMPV6_MGM_QUERY:
	317	case ICMPV6_MGM_REPORT:
	318	case ICMPV6_MGM_REDUCTION:
	319	case ICMPV6_MLD2_REPORT:
a50feda5	320	deliver = true;
7bc570c8	321	break;
7bc570c8	322	}
7bc570c8 YH	323	goto out;
	324	}
	325	/* unknown RA - process it normally */
	326	}
1da177e4	327
7bc570c8 YH	328	if (deliver)
	329	skb2 = skb_clone(skb, GFP_ATOMIC);
	330	else {
	331	skb2 = skb;
	332	skb = NULL;
	333	}
1ab1457c	334
7bc570c8	335	if (skb2) {
7bc570c8	336	ip6_mr_input(skb2);
1da177e4 LT	337	}
1da177e4 LT	338	}
7bc570c8	339	out:
aba6096b YH	340	#endif
aba6096b YH	341	if (likely(deliver))
1da177e4	342	ip6_input(skb);
aba6096b YH	343	else {
	344	/* discard */
	345	kfree_skb(skb);
1da177e4	346	}
1da177e4 LT	347
	348	return 0;
	349	}