[linux-2.6-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
	 * 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 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),
			 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_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	/*
	126	* RFC4291 2.5.3
	127	* A packet received on an interface with a destination address
	128	* of loopback must be dropped.
	129	*/
	130	if (!(dev->flags & IFF_LOOPBACK) &&
	131	ipv6_addr_loopback(&hdr->daddr))
	132	goto err;
	133
1c4a154e HFS	134	/* RFC4291 Errata ID: 3480
	135	* Interface-Local scope spans only a single interface on a
	136	* node and is useful only for loopback transmission of
	137	* multicast. Packets with interface-local scope received
	138	* from another node must be discarded.
	139	*/
	140	if (!(skb->pkt_type == PACKET_LOOPBACK \|\|
	141	dev->flags & IFF_LOOPBACK) &&
	142	ipv6_addr_is_multicast(&hdr->daddr) &&
	143	IPV6_ADDR_MC_SCOPE(&hdr->daddr) == 1)
	144	goto err;
	145
abbc3043 JB	146	/* If enabled, drop unicast packets that were encapsulated in link-layer
	147	* multicast or broadcast to protected against the so-called "hole-196"
	148	* attack in 802.11 wireless.
	149	*/
	150	if (!ipv6_addr_is_multicast(&hdr->daddr) &&
	151	(skb->pkt_type == PACKET_BROADCAST \|\|
	152	skb->pkt_type == PACKET_MULTICAST) &&
	153	idev->cnf.drop_unicast_in_l2_multicast)
	154	goto err;
	155
20314092 HFS	156	/* RFC4291 2.7
	157	* Nodes must not originate a packet to a multicast address whose scope
	158	* field contains the reserved value 0; if such a packet is received, it
	159	* must be silently dropped.
	160	*/
	161	if (ipv6_addr_is_multicast(&hdr->daddr) &&
	162	IPV6_ADDR_MC_SCOPE(&hdr->daddr) == 0)
	163	goto err;
	164
c457338d BH	165	/*
	166	* RFC4291 2.7
	167	* Multicast addresses must not be used as source addresses in IPv6
	168	* packets or appear in any Routing header.
	169	*/
	170	if (ipv6_addr_is_multicast(&hdr->saddr))
	171	goto err;
	172
b0e380b1	173	skb->transport_header = skb->network_header + sizeof(*hdr);
951dbc8a PM	174	IP6CB(skb)->nhoff = offsetof(struct ipv6hdr, nexthdr);
951dbc8a PM	175
1da177e4 LT	176	pkt_len = ntohs(hdr->payload_len);
	177
	178	/* pkt_len may be zero if Jumbo payload option is present */
	179	if (pkt_len \|\| hdr->nexthdr != NEXTHDR_HOP) {
60e5c166	180	if (pkt_len + sizeof(struct ipv6hdr) > skb->len) {
1d015503 ED	181	__IP6_INC_STATS(net,
1d015503 ED	182	idev, IPSTATS_MIB_INTRUNCATEDPKTS);
60e5c166 MC	183	goto drop;
60e5c166 MC	184	}
1da177e4	185	if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr))) {
1d015503	186	__IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
1da177e4 LT	187	goto drop;
1da177e4 LT	188	}
0660e03f	189	hdr = ipv6_hdr(skb);
1da177e4 LT	190	}
	191
	192	if (hdr->nexthdr == NEXTHDR_HOP) {
e5bbef20	193	if (ipv6_parse_hopopts(skb) < 0) {
1d015503	194	__IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
a11d206d	195	rcu_read_unlock();
5c91face	196	return NET_RX_DROP;
1da177e4	197	}
1da177e4 LT	198	}
1da177e4 LT	199
a11d206d YH	200	rcu_read_unlock();
a11d206d YH	201
71f9dacd HX	202	/* Must drop socket now because of tproxy. */
	203	skb_orphan(skb);
	204
29a26a56 EB	205	return NF_HOOK(NFPROTO_IPV6, NF_INET_PRE_ROUTING,
29a26a56 EB	206	net, NULL, skb, dev, NULL,
6e23ae2a	207	ip6_rcv_finish);
1da177e4	208	err:
1d015503	209	__IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
1da177e4	210	drop:
a11d206d	211	rcu_read_unlock();
1da177e4	212	kfree_skb(skb);
5c91face	213	return NET_RX_DROP;
1da177e4 LT	214	}
	215
	216	/*
	217	* Deliver the packet to the host
	218	*/
	219
	220
0c4b51f0	221	static int ip6_input_finish(struct net net, struct sock sk, struct sk_buff *skb)
1da177e4	222	{
41135cc8	223	const struct inet6_protocol *ipprot;
f9242b6b	224	struct inet6_dev *idev;
1da177e4	225	unsigned int nhoff;
a50feda5 ED	226	int nexthdr;
a50feda5 ED	227	bool raw;
1da44f9c	228	bool have_final = false;
1da177e4	229
1da177e4 LT	230	/*
	231	* Parse extension headers
	232	*/
	233
1da177e4	234	rcu_read_lock();
1b0ccfe5	235	resubmit:
adf30907	236	idev = ip6_dst_idev(skb_dst(skb));
ea2ae17d	237	if (!pskb_pull(skb, skb_transport_offset(skb)))
1da177e4	238	goto discard;
951dbc8a	239	nhoff = IP6CB(skb)->nhoff;
d56f90a7	240	nexthdr = skb_network_header(skb)[nhoff];
1da177e4	241
4c64242a	242	resubmit_final:
69d6da0b	243	raw = raw6_local_deliver(skb, nexthdr);
e5d08d71	244	ipprot = rcu_dereference(inet6_protos[nexthdr]);
53b24b8f	245	if (ipprot) {
1da177e4	246	int ret;
1ab1457c	247
1da44f9c TH	248	if (have_final) {
	249	if (!(ipprot->flags & INET6_PROTO_FINAL)) {
	250	/* Once we've seen a final protocol don't
	251	* allow encapsulation on any non-final
	252	* ones. This allows foo in UDP encapsulation
	253	* to work.
	254	*/
	255	goto discard;
	256	}
	257	} else if (ipprot->flags & INET6_PROTO_FINAL) {
b71d1d42	258	const struct ipv6hdr *hdr;
1da177e4	259
1da44f9c TH	260	/* Only do this once for first final protocol */
	261	have_final = true;
	262
9fb9cbb1 YK	263	/* Free reference early: we don't need it any more,
	264	and it may hold ip_conntrack module loaded
	265	indefinitely. */
	266	nf_reset(skb);
	267
d56f90a7	268	skb_postpull_rcsum(skb, skb_network_header(skb),
cfe1fc77	269	skb_network_header_len(skb));
0660e03f	270	hdr = ipv6_hdr(skb);
1da177e4 LT	271	if (ipv6_addr_is_multicast(&hdr->daddr) &&
	272	!ipv6_chk_mcast_addr(skb->dev, &hdr->daddr,
	273	&hdr->saddr) &&
daad1512	274	!ipv6_is_mld(skb, nexthdr, skb_network_header_len(skb)))
1da177e4 LT	275	goto discard;
	276	}
	277	if (!(ipprot->flags & INET6_PROTO_NOPOLICY) &&
1ab1457c	278	!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
1da177e4	279	goto discard;
1ab1457c	280
e5bbef20	281	ret = ipprot->handler(skb);
4c64242a TH	282	if (ret > 0) {
	283	if (ipprot->flags & INET6_PROTO_FINAL) {
	284	/* Not an extension header, most likely UDP
	285	* encapsulation. Use return value as nexthdr
	286	* protocol not nhoff (which presumably is
	287	* not set by handler).
	288	*/
	289	nexthdr = ret;
	290	goto resubmit_final;
	291	} else {
	292	goto resubmit;
	293	}
	294	} else if (ret == 0) {
1d015503	295	__IP6_INC_STATS(net, idev, IPSTATS_MIB_INDELIVERS);
4c64242a	296	}
1da177e4	297	} else {
69d6da0b	298	if (!raw) {
1da177e4	299	if (xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1d015503 ED	300	__IP6_INC_STATS(net, idev,
1d015503 ED	301	IPSTATS_MIB_INUNKNOWNPROTOS);
fad87aca	302	icmpv6_send(skb, ICMPV6_PARAMPROB,
3ffe533c	303	ICMPV6_UNK_NEXTHDR, nhoff);
1da177e4	304	}
d8c6f4b9 NH	305	kfree_skb(skb);
d8c6f4b9 NH	306	} else {
1d015503	307	__IP6_INC_STATS(net, idev, IPSTATS_MIB_INDELIVERS);
d8c6f4b9 NH	308	consume_skb(skb);
d8c6f4b9 NH	309	}
1da177e4 LT	310	}
	311	rcu_read_unlock();
	312	return 0;
	313
	314	discard:
1d015503	315	__IP6_INC_STATS(net, idev, IPSTATS_MIB_INDISCARDS);
1da177e4 LT	316	rcu_read_unlock();
	317	kfree_skb(skb);
	318	return 0;
	319	}
	320
	321
	322	int ip6_input(struct sk_buff *skb)
	323	{
29a26a56 EB	324	return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_IN,
29a26a56 EB	325	dev_net(skb->dev), NULL, skb, skb->dev, NULL,
6e23ae2a	326	ip6_input_finish);
1da177e4	327	}
b4869aa2	328	EXPORT_SYMBOL_GPL(ip6_input);
1da177e4 LT	329
	330	int ip6_mc_input(struct sk_buff *skb)
	331	{
b71d1d42	332	const struct ipv6hdr *hdr;
a50feda5	333	bool deliver;
1da177e4	334
c2005eb0	335	__IP6_UPD_PO_STATS(dev_net(skb_dst(skb)->dev),
adf30907	336	ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_INMCAST,
edf391ff	337	skb->len);
1da177e4	338
0660e03f	339	hdr = ipv6_hdr(skb);
4c7966b8	340	deliver = ipv6_chk_mcast_addr(skb->dev, &hdr->daddr, NULL);
1da177e4	341
7bc570c8	342	#ifdef CONFIG_IPV6_MROUTE
1da177e4	343	/*
7bc570c8	344	* IPv6 multicast router mode is now supported ;)
1da177e4	345	*/
53b7997f	346	if (dev_net(skb->dev)->ipv6.devconf_all->mc_forwarding &&
ddf64354 HFS	347	!(ipv6_addr_type(&hdr->daddr) &
ddf64354 HFS	348	(IPV6_ADDR_LOOPBACK\|IPV6_ADDR_LINKLOCAL)) &&
7bc570c8 YH	349	likely(!(IP6CB(skb)->flags & IP6SKB_FORWARDED))) {
	350	/*
	351	* Okay, we try to forward - split and duplicate
	352	* packets.
	353	*/
	354	struct sk_buff *skb2;
	355	struct inet6_skb_parm *opt = IP6CB(skb);
	356
	357	/* Check for MLD */
dd3332bf	358	if (unlikely(opt->flags & IP6SKB_ROUTERALERT)) {
7bc570c8	359	/* Check if this is a mld message */
7bc570c8	360	u8 nexthdr = hdr->nexthdr;
75f2811c	361	__be16 frag_off;
7bc570c8 YH	362	int offset;
	363
	364	/* Check if the value of Router Alert
	365	* is for MLD (0x0000).
	366	*/
dd3332bf	367	if (opt->ra == htons(IPV6_OPT_ROUTERALERT_MLD)) {
a50feda5	368	deliver = false;
aba6096b	369
7bc570c8 YH	370	if (!ipv6_ext_hdr(nexthdr)) {
7bc570c8 YH	371	/* BUG */
aba6096b	372	goto out;
7bc570c8 YH	373	}
7bc570c8 YH	374	offset = ipv6_skip_exthdr(skb, sizeof(*hdr),
75f2811c	375	&nexthdr, &frag_off);
7bc570c8	376	if (offset < 0)
aba6096b	377	goto out;
7bc570c8	378
4c938d22 A	379	if (ipv6_is_mld(skb, nexthdr, offset))
4c938d22 A	380	deliver = true;
7bc570c8	381
4c938d22	382	goto out;
7bc570c8 YH	383	}
	384	/* unknown RA - process it normally */
	385	}
1da177e4	386
7bc570c8 YH	387	if (deliver)
	388	skb2 = skb_clone(skb, GFP_ATOMIC);
	389	else {
	390	skb2 = skb;
	391	skb = NULL;
	392	}
1ab1457c	393
7bc570c8	394	if (skb2) {
7bc570c8	395	ip6_mr_input(skb2);
1da177e4 LT	396	}
1da177e4 LT	397	}
7bc570c8	398	out:
aba6096b YH	399	#endif
aba6096b YH	400	if (likely(deliver))
1da177e4	401	ip6_input(skb);
aba6096b YH	402	else {
	403	/* discard */
	404	kfree_skb(skb);
1da177e4	405	}
1da177e4 LT	406
	407	return 0;
	408	}