[deliverable/linux.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>
 *
 *	$Id: ip6_input.c,v 1.19 2000/12/13 18:31:50 davem Exp $
 *
 *	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/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>


inline int ip6_rcv_finish( struct sk_buff *skb)
{
	if (skb->dst == NULL)
		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)
{
	struct ipv6hdr *hdr;
	u32 		pkt_len;
	struct inet6_dev *idev;

	if (skb->pkt_type == PACKET_OTHERHOST) {
		kfree_skb(skb);
		return 0;
	}

	rcu_read_lock();

	idev = __in6_dev_get(skb->dev);

	IP6_INC_STATS_BH(idev, IPSTATS_MIB_INRECEIVES);

	if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL) {
		IP6_INC_STATS_BH(idev, IPSTATS_MIB_INDISCARDS);
		rcu_read_unlock();
		goto out;
	}

	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 ? ip6_dst_idev(skb->dst)->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;

	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(idev, IPSTATS_MIB_INTRUNCATEDPKTS);
			goto drop;
		}
		if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr))) {
			IP6_INC_STATS_BH(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(idev, IPSTATS_MIB_INHDRERRORS);
			rcu_read_unlock();
			return 0;
		}
	}

	rcu_read_unlock();

	return NF_HOOK(PF_INET6, NF_INET_PRE_ROUTING, skb, dev, NULL,
		       ip6_rcv_finish);
err:
	IP6_INC_STATS_BH(idev, IPSTATS_MIB_INHDRERRORS);
drop:
	rcu_read_unlock();
	kfree_skb(skb);
out:
	return 0;
}

/*
 *	Deliver the packet to the host
 */


static int ip6_input_finish(struct sk_buff *skb)
{
	struct inet6_protocol *ipprot;
	unsigned int nhoff;
	int nexthdr, raw;
	u8 hash;
	struct inet6_dev *idev;

	/*
	 *	Parse extension headers
	 */

	rcu_read_lock();
resubmit:
	idev = ip6_dst_idev(skb->dst);
	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);

	hash = nexthdr & (MAX_INET_PROTOS - 1);
	if ((ipprot = rcu_dereference(inet6_protos[hash])) != NULL) {
		int ret;

		if (ipprot->flags & INET6_PROTO_FINAL) {
			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(idev, IPSTATS_MIB_INDELIVERS);
	} else {
		if (!raw) {
			if (xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
				IP6_INC_STATS_BH(idev, IPSTATS_MIB_INUNKNOWNPROTOS);
				icmpv6_send(skb, ICMPV6_PARAMPROB,
					    ICMPV6_UNK_NEXTHDR, nhoff,
					    skb->dev);
			}
		} else
			IP6_INC_STATS_BH(idev, IPSTATS_MIB_INDELIVERS);
		kfree_skb(skb);
	}
	rcu_read_unlock();
	return 0;

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


int ip6_input(struct sk_buff *skb)
{
	return NF_HOOK(PF_INET6, NF_INET_LOCAL_IN, skb, skb->dev, NULL,
		       ip6_input_finish);
}

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

	IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_INMCASTPKTS);

	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 (ipv6_devconf.mc_forwarding &&
	    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;
			int offset;

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

				if (!ipv6_ext_hdr(nexthdr)) {
					/* BUG */
					goto out;
				}
				offset = ipv6_skip_exthdr(skb, sizeof(*hdr),
							  &nexthdr);
				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 = 1;
					break;
				}
				goto out;
			}
			/* unknown RA - process it normally */
		}

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

		if (skb2) {
			skb2->dev = skb2->dst->dev;
			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	*
	9	* $Id: ip6_input.c,v 1.19 2000/12/13 18:31:50 davem Exp $
	10	*
	11	* Based in linux/net/ipv4/ip_input.c
	12	*
	13	* This program is free software; you can redistribute it and/or
	14	* modify it under the terms of the GNU General Public License
	15	* as published by the Free Software Foundation; either version
	16	* 2 of the License, or (at your option) any later version.
	17	*/
	18	/* Changes
	19	*
	20	* Mitsuru KANDA @USAGI and
	21	* YOSHIFUJI Hideaki @USAGI: Remove ipv6_parse_exthdrs().
	22	*/
	23
	24	#include <linux/errno.h>
	25	#include <linux/types.h>
	26	#include <linux/socket.h>
	27	#include <linux/sockios.h>
1da177e4 LT	28	#include <linux/net.h>
	29	#include <linux/netdevice.h>
	30	#include <linux/in6.h>
	31	#include <linux/icmpv6.h>
7bc570c8	32	#include <linux/mroute6.h>
1da177e4 LT	33
	34	#include <linux/netfilter.h>
	35	#include <linux/netfilter_ipv6.h>
	36
	37	#include <net/sock.h>
	38	#include <net/snmp.h>
	39
	40	#include <net/ipv6.h>
	41	#include <net/protocol.h>
	42	#include <net/transp_v6.h>
	43	#include <net/rawv6.h>
	44	#include <net/ndisc.h>
	45	#include <net/ip6_route.h>
	46	#include <net/addrconf.h>
	47	#include <net/xfrm.h>
	48
	49
	50
1ab1457c	51	inline int ip6_rcv_finish( struct sk_buff *skb)
1da177e4 LT	52	{
	53	if (skb->dst == NULL)
	54	ip6_route_input(skb);
	55
	56	return dst_input(skb);
	57	}
	58
f2ccd8fa	59	int ipv6_rcv(struct sk_buff skb, struct net_device dev, struct packet_type pt, struct net_device orig_dev)
1da177e4 LT	60	{
	61	struct ipv6hdr *hdr;
	62	u32 pkt_len;
a11d206d	63	struct inet6_dev *idev;
1da177e4	64
a11d206d YH	65	if (skb->pkt_type == PACKET_OTHERHOST) {
	66	kfree_skb(skb);
	67	return 0;
	68	}
	69
	70	rcu_read_lock();
1da177e4	71
a11d206d YH	72	idev = __in6_dev_get(skb->dev);
	73
	74	IP6_INC_STATS_BH(idev, IPSTATS_MIB_INRECEIVES);
1da177e4 LT	75
1da177e4 LT	76	if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL) {
a11d206d YH	77	IP6_INC_STATS_BH(idev, IPSTATS_MIB_INDISCARDS);
a11d206d YH	78	rcu_read_unlock();
1da177e4 LT	79	goto out;
	80	}
	81
6b7fdc3a GC	82	memset(IP6CB(skb), 0, sizeof(struct inet6_skb_parm));
6b7fdc3a GC	83
1da177e4 LT	84	/*
	85	* Store incoming device index. When the packet will
	86	* be queued, we cannot refer to skb->dev anymore.
	87	*
	88	* BTW, when we send a packet for our own local address on a
	89	* non-loopback interface (e.g. ethX), it is being delivered
de3cb747	90	* via the loopback interface (lo) here; skb->dev = loopback_dev.
1da177e4 LT	91	* It, however, should be considered as if it is being
	92	* arrived via the sending interface (ethX), because of the
	93	* nature of scoping architecture. --yoshfuji
	94	*/
7a3025b1	95	IP6CB(skb)->iif = skb->dst ? ip6_dst_idev(skb->dst)->dev->ifindex : dev->ifindex;
1da177e4	96
2889139a	97	if (unlikely(!pskb_may_pull(skb, sizeof(*hdr))))
1da177e4 LT	98	goto err;
1da177e4 LT	99
0660e03f	100	hdr = ipv6_hdr(skb);
1da177e4 LT	101
	102	if (hdr->version != 6)
	103	goto err;
	104
f630e43a YH	105	/*
	106	* RFC4291 2.5.3
	107	* A packet received on an interface with a destination address
	108	* of loopback must be dropped.
	109	*/
	110	if (!(dev->flags & IFF_LOOPBACK) &&
	111	ipv6_addr_loopback(&hdr->daddr))
	112	goto err;
	113
b0e380b1	114	skb->transport_header = skb->network_header + sizeof(*hdr);
951dbc8a PM	115	IP6CB(skb)->nhoff = offsetof(struct ipv6hdr, nexthdr);
951dbc8a PM	116
1da177e4 LT	117	pkt_len = ntohs(hdr->payload_len);
	118
	119	/* pkt_len may be zero if Jumbo payload option is present */
	120	if (pkt_len \|\| hdr->nexthdr != NEXTHDR_HOP) {
60e5c166 MC	121	if (pkt_len + sizeof(struct ipv6hdr) > skb->len) {
	122	IP6_INC_STATS_BH(idev, IPSTATS_MIB_INTRUNCATEDPKTS);
	123	goto drop;
	124	}
1da177e4	125	if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr))) {
a11d206d	126	IP6_INC_STATS_BH(idev, IPSTATS_MIB_INHDRERRORS);
1da177e4 LT	127	goto drop;
1da177e4 LT	128	}
0660e03f	129	hdr = ipv6_hdr(skb);
1da177e4 LT	130	}
	131
	132	if (hdr->nexthdr == NEXTHDR_HOP) {
e5bbef20	133	if (ipv6_parse_hopopts(skb) < 0) {
a11d206d YH	134	IP6_INC_STATS_BH(idev, IPSTATS_MIB_INHDRERRORS);
a11d206d YH	135	rcu_read_unlock();
1da177e4 LT	136	return 0;
1da177e4 LT	137	}
1da177e4 LT	138	}
1da177e4 LT	139
a11d206d YH	140	rcu_read_unlock();
a11d206d YH	141
6e23ae2a PM	142	return NF_HOOK(PF_INET6, NF_INET_PRE_ROUTING, skb, dev, NULL,
6e23ae2a PM	143	ip6_rcv_finish);
1da177e4	144	err:
a11d206d	145	IP6_INC_STATS_BH(idev, IPSTATS_MIB_INHDRERRORS);
1da177e4	146	drop:
a11d206d	147	rcu_read_unlock();
1da177e4 LT	148	kfree_skb(skb);
	149	out:
	150	return 0;
	151	}
	152
	153	/*
	154	* Deliver the packet to the host
	155	*/
	156
	157
ad643a79	158	static int ip6_input_finish(struct sk_buff *skb)
1da177e4 LT	159	{
1da177e4 LT	160	struct inet6_protocol *ipprot;
1da177e4	161	unsigned int nhoff;
69d6da0b	162	int nexthdr, raw;
1da177e4	163	u8 hash;
a11d206d	164	struct inet6_dev *idev;
1da177e4	165
1da177e4 LT	166	/*
	167	* Parse extension headers
	168	*/
	169
1da177e4 LT	170	rcu_read_lock();
1da177e4 LT	171	resubmit:
a11d206d	172	idev = ip6_dst_idev(skb->dst);
ea2ae17d	173	if (!pskb_pull(skb, skb_transport_offset(skb)))
1da177e4	174	goto discard;
951dbc8a	175	nhoff = IP6CB(skb)->nhoff;
d56f90a7	176	nexthdr = skb_network_header(skb)[nhoff];
1da177e4	177
69d6da0b	178	raw = raw6_local_deliver(skb, nexthdr);
1da177e4 LT	179
	180	hash = nexthdr & (MAX_INET_PROTOS - 1);
	181	if ((ipprot = rcu_dereference(inet6_protos[hash])) != NULL) {
	182	int ret;
1ab1457c	183
1da177e4	184	if (ipprot->flags & INET6_PROTO_FINAL) {
1ab1457c	185	struct ipv6hdr *hdr;
1da177e4	186
9fb9cbb1 YK	187	/* Free reference early: we don't need it any more,
	188	and it may hold ip_conntrack module loaded
	189	indefinitely. */
	190	nf_reset(skb);
	191
d56f90a7	192	skb_postpull_rcsum(skb, skb_network_header(skb),
cfe1fc77	193	skb_network_header_len(skb));
0660e03f	194	hdr = ipv6_hdr(skb);
1da177e4 LT	195	if (ipv6_addr_is_multicast(&hdr->daddr) &&
	196	!ipv6_chk_mcast_addr(skb->dev, &hdr->daddr,
	197	&hdr->saddr) &&
	198	!ipv6_is_mld(skb, nexthdr))
	199	goto discard;
	200	}
	201	if (!(ipprot->flags & INET6_PROTO_NOPOLICY) &&
1ab1457c	202	!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
1da177e4	203	goto discard;
1ab1457c	204
e5bbef20	205	ret = ipprot->handler(skb);
1da177e4 LT	206	if (ret > 0)
	207	goto resubmit;
	208	else if (ret == 0)
a11d206d	209	IP6_INC_STATS_BH(idev, IPSTATS_MIB_INDELIVERS);
1da177e4	210	} else {
69d6da0b	211	if (!raw) {
1da177e4	212	if (xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
a11d206d	213	IP6_INC_STATS_BH(idev, IPSTATS_MIB_INUNKNOWNPROTOS);
fad87aca	214	icmpv6_send(skb, ICMPV6_PARAMPROB,
1ab1457c YH	215	ICMPV6_UNK_NEXTHDR, nhoff,
1ab1457c YH	216	skb->dev);
1da177e4	217	}
fad87aca	218	} else
a11d206d	219	IP6_INC_STATS_BH(idev, IPSTATS_MIB_INDELIVERS);
fad87aca	220	kfree_skb(skb);
1da177e4 LT	221	}
	222	rcu_read_unlock();
	223	return 0;
	224
	225	discard:
a11d206d	226	IP6_INC_STATS_BH(idev, IPSTATS_MIB_INDISCARDS);
1da177e4 LT	227	rcu_read_unlock();
	228	kfree_skb(skb);
	229	return 0;
	230	}
	231
	232
	233	int ip6_input(struct sk_buff *skb)
	234	{
6e23ae2a PM	235	return NF_HOOK(PF_INET6, NF_INET_LOCAL_IN, skb, skb->dev, NULL,
6e23ae2a PM	236	ip6_input_finish);
1da177e4 LT	237	}
	238
	239	int ip6_mc_input(struct sk_buff *skb)
	240	{
	241	struct ipv6hdr *hdr;
	242	int deliver;
	243
a11d206d	244	IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_INMCASTPKTS);
1da177e4	245
0660e03f	246	hdr = ipv6_hdr(skb);
4c7966b8	247	deliver = ipv6_chk_mcast_addr(skb->dev, &hdr->daddr, NULL);
1da177e4	248
7bc570c8	249	#ifdef CONFIG_IPV6_MROUTE
1da177e4	250	/*
7bc570c8	251	* IPv6 multicast router mode is now supported ;)
1da177e4	252	*/
7bc570c8 YH	253	if (ipv6_devconf.mc_forwarding &&
	254	likely(!(IP6CB(skb)->flags & IP6SKB_FORWARDED))) {
	255	/*
	256	* Okay, we try to forward - split and duplicate
	257	* packets.
	258	*/
	259	struct sk_buff *skb2;
	260	struct inet6_skb_parm *opt = IP6CB(skb);
	261
	262	/* Check for MLD */
	263	if (unlikely(opt->ra)) {
	264	/* Check if this is a mld message */
	265	u8 *ptr = skb_network_header(skb) + opt->ra;
	266	struct icmp6hdr *icmp6;
	267	u8 nexthdr = hdr->nexthdr;
	268	int offset;
	269
	270	/* Check if the value of Router Alert
	271	* is for MLD (0x0000).
	272	*/
	273	if ((ptr[2] \| ptr[3]) == 0) {
aba6096b YH	274	deliver = 0;
aba6096b YH	275
7bc570c8 YH	276	if (!ipv6_ext_hdr(nexthdr)) {
7bc570c8 YH	277	/* BUG */
aba6096b	278	goto out;
7bc570c8 YH	279	}
	280	offset = ipv6_skip_exthdr(skb, sizeof(*hdr),
	281	&nexthdr);
	282	if (offset < 0)
aba6096b	283	goto out;
7bc570c8 YH	284
7bc570c8 YH	285	if (nexthdr != IPPROTO_ICMPV6)
aba6096b	286	goto out;
7bc570c8 YH	287
	288	if (!pskb_may_pull(skb, (skb_network_header(skb) +
	289	offset + 1 - skb->data)))
aba6096b	290	goto out;
7bc570c8 YH	291
	292	icmp6 = (struct icmp6hdr *)(skb_network_header(skb) + offset);
	293
	294	switch (icmp6->icmp6_type) {
	295	case ICMPV6_MGM_QUERY:
	296	case ICMPV6_MGM_REPORT:
	297	case ICMPV6_MGM_REDUCTION:
	298	case ICMPV6_MLD2_REPORT:
aba6096b	299	deliver = 1;
7bc570c8	300	break;
7bc570c8	301	}
7bc570c8 YH	302	goto out;
	303	}
	304	/* unknown RA - process it normally */
	305	}
1da177e4	306
7bc570c8 YH	307	if (deliver)
	308	skb2 = skb_clone(skb, GFP_ATOMIC);
	309	else {
	310	skb2 = skb;
	311	skb = NULL;
	312	}
1ab1457c	313
7bc570c8 YH	314	if (skb2) {
	315	skb2->dev = skb2->dst->dev;
	316	ip6_mr_input(skb2);
1da177e4 LT	317	}
1da177e4 LT	318	}
7bc570c8	319	out:
aba6096b YH	320	#endif
aba6096b YH	321	if (likely(deliver))
1da177e4	322	ip6_input(skb);
aba6096b YH	323	else {
	324	/* discard */
	325	kfree_skb(skb);
1da177e4	326	}
1da177e4 LT	327
	328	return 0;
	329	}