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

/*
 *	IPv6 input
 *	Linux INET6 implementation
 *
 *	Authors:
 *	Pedro Roque		<roque@di.fc.ul.pt>
 *	Ian P. Morris		<I.P.Morris@soton.ac.uk>
 *
 *	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>
#include <net/inet_ecn.h>
#include <net/dst_metadata.h>

int ip6_rcv_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
{
	void (*edemux)(struct sk_buff *skb);

	/* if ingress device is enslaved to an L3 master device pass the
	 * skb to its handler for processing
	 */
	skb = l3mdev_ip6_rcv(skb);
	if (!skb)
		return NET_RX_SUCCESS;

	if (net->ipv4.sysctl_ip_early_demux && !skb_dst(skb) && skb->sk == NULL) {
		const struct inet6_protocol *ipprot;

		ipprot = rcu_dereference(inet6_protos[ipv6_hdr(skb)->nexthdr]);
		if (ipprot && (edemux = READ_ONCE(ipprot->early_demux)))
			edemux(skb);
	}
	if (!skb_valid_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(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(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_valid_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;

	__IP6_ADD_STATS(net, idev,
			IPSTATS_MIB_NOECTPKTS +
				(ipv6_get_dsfield(hdr) & INET_ECN_MASK),
			max_t(unsigned short, 1, skb_shinfo(skb)->gso_segs));
	/*
	 * RFC4291 2.5.3
	 * The loopback address must not be used as the source address in IPv6
	 * packets that are sent outside of a single node. [..]
	 * A packet received on an interface with a destination address
	 * of loopback must be dropped.
	 */
	if ((ipv6_addr_loopback(&hdr->saddr) ||
	     ipv6_addr_loopback(&hdr->daddr)) &&
	     !(dev->flags & IFF_LOOPBACK))
		goto err;

	/* RFC4291 Errata ID: 3480
	 * Interface-Local scope spans only a single interface on a
	 * node and is useful only for loopback transmission of
	 * multicast.  Packets with interface-local scope received
	 * from another node must be discarded.
	 */
	if (!(skb->pkt_type == PACKET_LOOPBACK ||
	      dev->flags & IFF_LOOPBACK) &&
	    ipv6_addr_is_multicast(&hdr->daddr) &&
	    IPV6_ADDR_MC_SCOPE(&hdr->daddr) == 1)
		goto err;

	/* If enabled, drop unicast packets that were encapsulated in link-layer
	 * multicast or broadcast to protected against the so-called "hole-196"
	 * attack in 802.11 wireless.
	 */
	if (!ipv6_addr_is_multicast(&hdr->daddr) &&
	    (skb->pkt_type == PACKET_BROADCAST ||
	     skb->pkt_type == PACKET_MULTICAST) &&
	    idev->cnf.drop_unicast_in_l2_multicast)
		goto err;

	/* RFC4291 2.7
	 * Nodes must not originate a packet to a multicast address whose scope
	 * field contains the reserved value 0; if such a packet is received, it
	 * must be silently dropped.
	 */
	if (ipv6_addr_is_multicast(&hdr->daddr) &&
	    IPV6_ADDR_MC_SCOPE(&hdr->daddr) == 0)
		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(net,
					idev, IPSTATS_MIB_INTRUNCATEDPKTS);
			goto drop;
		}
		if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr))) {
			__IP6_INC_STATS(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(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,
		       net, NULL, skb, dev, NULL,
		       ip6_rcv_finish);
err:
	__IP6_INC_STATS(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 net *net, struct sock *sk, struct sk_buff *skb)
{
	const struct inet6_protocol *ipprot;
	struct inet6_dev *idev;
	unsigned int nhoff;
	int nexthdr;
	bool raw;
	bool have_final = false;

	/*
	 *	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];

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

		if (have_final) {
			if (!(ipprot->flags & INET6_PROTO_FINAL)) {
				/* Once we've seen a final protocol don't
				 * allow encapsulation on any non-final
				 * ones. This allows foo in UDP encapsulation
				 * to work.
				 */
				goto discard;
			}
		} else if (ipprot->flags & INET6_PROTO_FINAL) {
			const struct ipv6hdr *hdr;

			/* Only do this once for first final protocol */
			have_final = true;

			/* 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, skb_network_header_len(skb)))
				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) {
			if (ipprot->flags & INET6_PROTO_FINAL) {
				/* Not an extension header, most likely UDP
				 * encapsulation. Use return value as nexthdr
				 * protocol not nhoff (which presumably is
				 * not set by handler).
				 */
				nexthdr = ret;
				goto resubmit_final;
			} else {
				goto resubmit;
			}
		} else if (ret == 0) {
			__IP6_INC_STATS(net, idev, IPSTATS_MIB_INDELIVERS);
		}
	} else {
		if (!raw) {
			if (xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
				__IP6_INC_STATS(net, idev,
						IPSTATS_MIB_INUNKNOWNPROTOS);
				icmpv6_send(skb, ICMPV6_PARAMPROB,
					    ICMPV6_UNK_NEXTHDR, nhoff);
			}
			kfree_skb(skb);
		} else {
			__IP6_INC_STATS(net, idev, IPSTATS_MIB_INDELIVERS);
			consume_skb(skb);
		}
	}
	rcu_read_unlock();
	return 0;

discard:
	__IP6_INC_STATS(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,
		       dev_net(skb->dev), NULL, skb, skb->dev, NULL,
		       ip6_input_finish);
}
EXPORT_SYMBOL_GPL(ip6_input);

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

	__IP6_UPD_PO_STATS(dev_net(skb_dst(skb)->dev),
			 __in6_dev_get_safely(skb->dev), 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_LOOPBACK|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->flags & IP6SKB_ROUTERALERT)) {
			/* Check if this is a mld message */
			u8 nexthdr = hdr->nexthdr;
			__be16 frag_off;
			int offset;

			/* Check if the value of Router Alert
			 * is for MLD (0x0000).
			 */
			if (opt->ra == htons(IPV6_OPT_ROUTERALERT_MLD)) {
				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 (ipv6_is_mld(skb, nexthdr, offset))
					deliver = true;

				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 <roque@di.fc.ul.pt>
	7	* Ian P. Morris <I.P.Morris@soton.ac.uk>
	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	*
67ba4152 IM	18	* Mitsuru KANDA @USAGI and
67ba4152 IM	19	* YOSHIFUJI Hideaki @USAGI: Remove ipv6_parse_exthdrs().
1da177e4 LT	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>
1f07d03e	47	#include <net/inet_ecn.h>
48fb6b55	48	#include <net/dst_metadata.h>
1da177e4	49
0c4b51f0	50	int ip6_rcv_finish(struct net net, struct sock sk, struct sk_buff *skb)
1da177e4	51	{
dddb64bc	52	void (edemux)(struct sk_buff skb);
dddb64bc	53
74b20582 DA	54	/* if ingress device is enslaved to an L3 master device pass the
	55	* skb to its handler for processing
	56	*/
	57	skb = l3mdev_ip6_rcv(skb);
	58	if (!skb)
	59	return NET_RX_SUCCESS;
	60
e21145a9	61	if (net->ipv4.sysctl_ip_early_demux && !skb_dst(skb) && skb->sk == NULL) {
c7109986 ED	62	const struct inet6_protocol *ipprot;
c7109986 ED	63
c7109986	64	ipprot = rcu_dereference(inet6_protos[ipv6_hdr(skb)->nexthdr]);
dddb64bc	65	if (ipprot && (edemux = READ_ONCE(ipprot->early_demux)))
dddb64bc	66	edemux(skb);
c7109986	67	}
48fb6b55	68	if (!skb_valid_dst(skb))
1da177e4 LT	69	ip6_route_input(skb);
	70
	71	return dst_input(skb);
	72	}
	73
f2ccd8fa	74	int ipv6_rcv(struct sk_buff skb, struct net_device dev, struct packet_type pt, struct net_device orig_dev)
1da177e4	75	{
b71d1d42	76	const struct ipv6hdr *hdr;
67ba4152	77	u32 pkt_len;
a11d206d	78	struct inet6_dev *idev;
483a47d2	79	struct net *net = dev_net(skb->dev);
1da177e4	80
a11d206d YH	81	if (skb->pkt_type == PACKET_OTHERHOST) {
a11d206d YH	82	kfree_skb(skb);
5c91face	83	return NET_RX_DROP;
a11d206d YH	84	}
	85
	86	rcu_read_lock();
1da177e4	87
a11d206d YH	88	idev = __in6_dev_get(skb->dev);
a11d206d YH	89
c2005eb0	90	__IP6_UPD_PO_STATS(net, idev, IPSTATS_MIB_IN, skb->len);
1da177e4	91
778d80be YH	92	if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL \|\|
778d80be YH	93	!idev \|\| unlikely(idev->cnf.disable_ipv6)) {
1d015503	94	__IP6_INC_STATS(net, idev, IPSTATS_MIB_INDISCARDS);
71f6f6df	95	goto drop;
1da177e4 LT	96	}
1da177e4 LT	97
6b7fdc3a GC	98	memset(IP6CB(skb), 0, sizeof(struct inet6_skb_parm));
6b7fdc3a GC	99
1da177e4 LT	100	/*
	101	* Store incoming device index. When the packet will
	102	* be queued, we cannot refer to skb->dev anymore.
	103	*
	104	* BTW, when we send a packet for our own local address on a
	105	* non-loopback interface (e.g. ethX), it is being delivered
de3cb747	106	* via the loopback interface (lo) here; skb->dev = loopback_dev.
1da177e4 LT	107	* It, however, should be considered as if it is being
	108	* arrived via the sending interface (ethX), because of the
	109	* nature of scoping architecture. --yoshfuji
	110	*/
48fb6b55	111	IP6CB(skb)->iif = skb_valid_dst(skb) ? ip6_dst_idev(skb_dst(skb))->dev->ifindex : dev->ifindex;
1da177e4	112
2889139a	113	if (unlikely(!pskb_may_pull(skb, sizeof(*hdr))))
1da177e4 LT	114	goto err;
1da177e4 LT	115
0660e03f	116	hdr = ipv6_hdr(skb);
1da177e4 LT	117
	118	if (hdr->version != 6)
	119	goto err;
	120
1d015503 ED	121	__IP6_ADD_STATS(net, idev,
1d015503 ED	122	IPSTATS_MIB_NOECTPKTS +
1f07d03e	123	(ipv6_get_dsfield(hdr) & INET_ECN_MASK),
1d015503	124	max_t(unsigned short, 1, skb_shinfo(skb)->gso_segs));
f630e43a YH	125	/*
f630e43a YH	126	* RFC4291 2.5.3
0aa8c13e FW	127	* The loopback address must not be used as the source address in IPv6
0aa8c13e FW	128	* packets that are sent outside of a single node. [..]
f630e43a YH	129	* A packet received on an interface with a destination address
	130	* of loopback must be dropped.
	131	*/
0aa8c13e FW	132	if ((ipv6_addr_loopback(&hdr->saddr) \|\|
	133	ipv6_addr_loopback(&hdr->daddr)) &&
	134	!(dev->flags & IFF_LOOPBACK))
f630e43a YH	135	goto err;
f630e43a YH	136
1c4a154e HFS	137	/* RFC4291 Errata ID: 3480
	138	* Interface-Local scope spans only a single interface on a
	139	* node and is useful only for loopback transmission of
	140	* multicast. Packets with interface-local scope received
	141	* from another node must be discarded.
	142	*/
	143	if (!(skb->pkt_type == PACKET_LOOPBACK \|\|
	144	dev->flags & IFF_LOOPBACK) &&
	145	ipv6_addr_is_multicast(&hdr->daddr) &&
	146	IPV6_ADDR_MC_SCOPE(&hdr->daddr) == 1)
	147	goto err;
	148
abbc3043 JB	149	/* If enabled, drop unicast packets that were encapsulated in link-layer
	150	* multicast or broadcast to protected against the so-called "hole-196"
	151	* attack in 802.11 wireless.
	152	*/
	153	if (!ipv6_addr_is_multicast(&hdr->daddr) &&
	154	(skb->pkt_type == PACKET_BROADCAST \|\|
	155	skb->pkt_type == PACKET_MULTICAST) &&
	156	idev->cnf.drop_unicast_in_l2_multicast)
	157	goto err;
	158
20314092 HFS	159	/* RFC4291 2.7
	160	* Nodes must not originate a packet to a multicast address whose scope
	161	* field contains the reserved value 0; if such a packet is received, it
	162	* must be silently dropped.
	163	*/
	164	if (ipv6_addr_is_multicast(&hdr->daddr) &&
	165	IPV6_ADDR_MC_SCOPE(&hdr->daddr) == 0)
	166	goto err;
	167
c457338d BH	168	/*
	169	* RFC4291 2.7
	170	* Multicast addresses must not be used as source addresses in IPv6
	171	* packets or appear in any Routing header.
	172	*/
	173	if (ipv6_addr_is_multicast(&hdr->saddr))
	174	goto err;
	175
b0e380b1	176	skb->transport_header = skb->network_header + sizeof(*hdr);
951dbc8a PM	177	IP6CB(skb)->nhoff = offsetof(struct ipv6hdr, nexthdr);
951dbc8a PM	178
1da177e4 LT	179	pkt_len = ntohs(hdr->payload_len);
	180
	181	/* pkt_len may be zero if Jumbo payload option is present */
	182	if (pkt_len \|\| hdr->nexthdr != NEXTHDR_HOP) {
60e5c166	183	if (pkt_len + sizeof(struct ipv6hdr) > skb->len) {
1d015503 ED	184	__IP6_INC_STATS(net,
1d015503 ED	185	idev, IPSTATS_MIB_INTRUNCATEDPKTS);
60e5c166 MC	186	goto drop;
60e5c166 MC	187	}
1da177e4	188	if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr))) {
1d015503	189	__IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
1da177e4 LT	190	goto drop;
1da177e4 LT	191	}
0660e03f	192	hdr = ipv6_hdr(skb);
1da177e4 LT	193	}
	194
	195	if (hdr->nexthdr == NEXTHDR_HOP) {
e5bbef20	196	if (ipv6_parse_hopopts(skb) < 0) {
1d015503	197	__IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
a11d206d	198	rcu_read_unlock();
5c91face	199	return NET_RX_DROP;
1da177e4	200	}
1da177e4 LT	201	}
1da177e4 LT	202
a11d206d YH	203	rcu_read_unlock();
a11d206d YH	204
71f9dacd HX	205	/* Must drop socket now because of tproxy. */
	206	skb_orphan(skb);
	207
29a26a56 EB	208	return NF_HOOK(NFPROTO_IPV6, NF_INET_PRE_ROUTING,
29a26a56 EB	209	net, NULL, skb, dev, NULL,
6e23ae2a	210	ip6_rcv_finish);
1da177e4	211	err:
1d015503	212	__IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
1da177e4	213	drop:
a11d206d	214	rcu_read_unlock();
1da177e4	215	kfree_skb(skb);
5c91face	216	return NET_RX_DROP;
1da177e4 LT	217	}
	218
	219	/*
	220	* Deliver the packet to the host
	221	*/
	222
	223
0c4b51f0	224	static int ip6_input_finish(struct net net, struct sock sk, struct sk_buff *skb)
1da177e4	225	{
41135cc8	226	const struct inet6_protocol *ipprot;
f9242b6b	227	struct inet6_dev *idev;
1da177e4	228	unsigned int nhoff;
a50feda5 ED	229	int nexthdr;
a50feda5 ED	230	bool raw;
1da44f9c	231	bool have_final = false;
1da177e4	232
1da177e4 LT	233	/*
	234	* Parse extension headers
	235	*/
	236
1da177e4	237	rcu_read_lock();
1b0ccfe5	238	resubmit:
adf30907	239	idev = ip6_dst_idev(skb_dst(skb));
ea2ae17d	240	if (!pskb_pull(skb, skb_transport_offset(skb)))
1da177e4	241	goto discard;
951dbc8a	242	nhoff = IP6CB(skb)->nhoff;
d56f90a7	243	nexthdr = skb_network_header(skb)[nhoff];
1da177e4	244
4c64242a	245	resubmit_final:
69d6da0b	246	raw = raw6_local_deliver(skb, nexthdr);
e5d08d71	247	ipprot = rcu_dereference(inet6_protos[nexthdr]);
53b24b8f	248	if (ipprot) {
1da177e4	249	int ret;
1ab1457c	250
1da44f9c TH	251	if (have_final) {
	252	if (!(ipprot->flags & INET6_PROTO_FINAL)) {
	253	/* Once we've seen a final protocol don't
	254	* allow encapsulation on any non-final
	255	* ones. This allows foo in UDP encapsulation
	256	* to work.
	257	*/
	258	goto discard;
	259	}
	260	} else if (ipprot->flags & INET6_PROTO_FINAL) {
b71d1d42	261	const struct ipv6hdr *hdr;
1da177e4	262
1da44f9c TH	263	/* Only do this once for first final protocol */
	264	have_final = true;
	265
9fb9cbb1 YK	266	/* Free reference early: we don't need it any more,
	267	and it may hold ip_conntrack module loaded
	268	indefinitely. */
	269	nf_reset(skb);
	270
d56f90a7	271	skb_postpull_rcsum(skb, skb_network_header(skb),
cfe1fc77	272	skb_network_header_len(skb));
0660e03f	273	hdr = ipv6_hdr(skb);
1da177e4 LT	274	if (ipv6_addr_is_multicast(&hdr->daddr) &&
	275	!ipv6_chk_mcast_addr(skb->dev, &hdr->daddr,
	276	&hdr->saddr) &&
daad1512	277	!ipv6_is_mld(skb, nexthdr, skb_network_header_len(skb)))
1da177e4 LT	278	goto discard;
	279	}
	280	if (!(ipprot->flags & INET6_PROTO_NOPOLICY) &&
1ab1457c	281	!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
1da177e4	282	goto discard;
1ab1457c	283
e5bbef20	284	ret = ipprot->handler(skb);
4c64242a TH	285	if (ret > 0) {
	286	if (ipprot->flags & INET6_PROTO_FINAL) {
	287	/* Not an extension header, most likely UDP
	288	* encapsulation. Use return value as nexthdr
	289	* protocol not nhoff (which presumably is
	290	* not set by handler).
	291	*/
	292	nexthdr = ret;
	293	goto resubmit_final;
	294	} else {
	295	goto resubmit;
	296	}
	297	} else if (ret == 0) {
1d015503	298	__IP6_INC_STATS(net, idev, IPSTATS_MIB_INDELIVERS);
4c64242a	299	}
1da177e4	300	} else {
69d6da0b	301	if (!raw) {
1da177e4	302	if (xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1d015503 ED	303	__IP6_INC_STATS(net, idev,
1d015503 ED	304	IPSTATS_MIB_INUNKNOWNPROTOS);
fad87aca	305	icmpv6_send(skb, ICMPV6_PARAMPROB,
3ffe533c	306	ICMPV6_UNK_NEXTHDR, nhoff);
1da177e4	307	}
d8c6f4b9 NH	308	kfree_skb(skb);
d8c6f4b9 NH	309	} else {
1d015503	310	__IP6_INC_STATS(net, idev, IPSTATS_MIB_INDELIVERS);
d8c6f4b9 NH	311	consume_skb(skb);
d8c6f4b9 NH	312	}
1da177e4 LT	313	}
	314	rcu_read_unlock();
	315	return 0;
	316
	317	discard:
1d015503	318	__IP6_INC_STATS(net, idev, IPSTATS_MIB_INDISCARDS);
1da177e4 LT	319	rcu_read_unlock();
	320	kfree_skb(skb);
	321	return 0;
	322	}
	323
	324
	325	int ip6_input(struct sk_buff *skb)
	326	{
29a26a56 EB	327	return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_IN,
29a26a56 EB	328	dev_net(skb->dev), NULL, skb, skb->dev, NULL,
6e23ae2a	329	ip6_input_finish);
1da177e4	330	}
b4869aa2	331	EXPORT_SYMBOL_GPL(ip6_input);
1da177e4 LT	332
	333	int ip6_mc_input(struct sk_buff *skb)
	334	{
b71d1d42	335	const struct ipv6hdr *hdr;
a50feda5	336	bool deliver;
1da177e4	337
c2005eb0	338	__IP6_UPD_PO_STATS(dev_net(skb_dst(skb)->dev),
bdb7cc64	339	__in6_dev_get_safely(skb->dev), IPSTATS_MIB_INMCAST,
edf391ff	340	skb->len);
1da177e4	341
0660e03f	342	hdr = ipv6_hdr(skb);
4c7966b8	343	deliver = ipv6_chk_mcast_addr(skb->dev, &hdr->daddr, NULL);
1da177e4	344
7bc570c8	345	#ifdef CONFIG_IPV6_MROUTE
1da177e4	346	/*
7bc570c8	347	* IPv6 multicast router mode is now supported ;)
1da177e4	348	*/
53b7997f	349	if (dev_net(skb->dev)->ipv6.devconf_all->mc_forwarding &&
ddf64354 HFS	350	!(ipv6_addr_type(&hdr->daddr) &
ddf64354 HFS	351	(IPV6_ADDR_LOOPBACK\|IPV6_ADDR_LINKLOCAL)) &&
7bc570c8 YH	352	likely(!(IP6CB(skb)->flags & IP6SKB_FORWARDED))) {
	353	/*
	354	* Okay, we try to forward - split and duplicate
	355	* packets.
	356	*/
	357	struct sk_buff *skb2;
	358	struct inet6_skb_parm *opt = IP6CB(skb);
	359
	360	/* Check for MLD */
dd3332bf	361	if (unlikely(opt->flags & IP6SKB_ROUTERALERT)) {
7bc570c8	362	/* Check if this is a mld message */
7bc570c8	363	u8 nexthdr = hdr->nexthdr;
75f2811c	364	__be16 frag_off;
7bc570c8 YH	365	int offset;
	366
	367	/* Check if the value of Router Alert
	368	* is for MLD (0x0000).
	369	*/
dd3332bf	370	if (opt->ra == htons(IPV6_OPT_ROUTERALERT_MLD)) {
a50feda5	371	deliver = false;
aba6096b	372
7bc570c8 YH	373	if (!ipv6_ext_hdr(nexthdr)) {
7bc570c8 YH	374	/* BUG */
aba6096b	375	goto out;
7bc570c8 YH	376	}
7bc570c8 YH	377	offset = ipv6_skip_exthdr(skb, sizeof(*hdr),
75f2811c	378	&nexthdr, &frag_off);
7bc570c8	379	if (offset < 0)
aba6096b	380	goto out;
7bc570c8	381
4c938d22 A	382	if (ipv6_is_mld(skb, nexthdr, offset))
4c938d22 A	383	deliver = true;
7bc570c8	384
4c938d22	385	goto out;
7bc570c8 YH	386	}
	387	/* unknown RA - process it normally */
	388	}
1da177e4	389
7bc570c8 YH	390	if (deliver)
	391	skb2 = skb_clone(skb, GFP_ATOMIC);
	392	else {
	393	skb2 = skb;
	394	skb = NULL;
	395	}
1ab1457c	396
7bc570c8	397	if (skb2) {
7bc570c8	398	ip6_mr_input(skb2);
1da177e4 LT	399	}
1da177e4 LT	400	}
7bc570c8	401	out:
aba6096b YH	402	#endif
aba6096b YH	403	if (likely(deliver))
1da177e4	404	ip6_input(skb);
aba6096b YH	405	else {
	406	/* discard */
	407	kfree_skb(skb);
1da177e4	408	}
1da177e4 LT	409
	410	return 0;
	411	}