[net-next-2.6.git] / net / ipv4 / ip_input.c

/*
 * INET		An implementation of the TCP/IP protocol suite for the LINUX
 *		operating system.  INET is implemented using the  BSD Socket
 *		interface as the means of communication with the user level.
 *
 *		The Internet Protocol (IP) module.
 *
 * Version:	$Id: ip_input.c,v 1.55 2002/01/12 07:39:45 davem Exp $
 *
 * Authors:	Ross Biro
 *		Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
 *		Donald Becker, <becker@super.org>
 *		Alan Cox, <Alan.Cox@linux.org>
 *		Richard Underwood
 *		Stefan Becker, <stefanb@yello.ping.de>
 *		Jorge Cwik, <jorge@laser.satlink.net>
 *		Arnt Gulbrandsen, <agulbra@nvg.unit.no>
 *		
 *
 * Fixes:
 *		Alan Cox	:	Commented a couple of minor bits of surplus code
 *		Alan Cox	:	Undefining IP_FORWARD doesn't include the code
 *					(just stops a compiler warning).
 *		Alan Cox	:	Frames with >=MAX_ROUTE record routes, strict routes or loose routes
 *					are junked rather than corrupting things.
 *		Alan Cox	:	Frames to bad broadcast subnets are dumped
 *					We used to process them non broadcast and
 *					boy could that cause havoc.
 *		Alan Cox	:	ip_forward sets the free flag on the
 *					new frame it queues. Still crap because
 *					it copies the frame but at least it
 *					doesn't eat memory too.
 *		Alan Cox	:	Generic queue code and memory fixes.
 *		Fred Van Kempen :	IP fragment support (borrowed from NET2E)
 *		Gerhard Koerting:	Forward fragmented frames correctly.
 *		Gerhard Koerting: 	Fixes to my fix of the above 8-).
 *		Gerhard Koerting:	IP interface addressing fix.
 *		Linus Torvalds	:	More robustness checks
 *		Alan Cox	:	Even more checks: Still not as robust as it ought to be
 *		Alan Cox	:	Save IP header pointer for later
 *		Alan Cox	:	ip option setting
 *		Alan Cox	:	Use ip_tos/ip_ttl settings
 *		Alan Cox	:	Fragmentation bogosity removed
 *					(Thanks to Mark.Bush@prg.ox.ac.uk)
 *		Dmitry Gorodchanin :	Send of a raw packet crash fix.
 *		Alan Cox	:	Silly ip bug when an overlength
 *					fragment turns up. Now frees the
 *					queue.
 *		Linus Torvalds/ :	Memory leakage on fragmentation
 *		Alan Cox	:	handling.
 *		Gerhard Koerting:	Forwarding uses IP priority hints
 *		Teemu Rantanen	:	Fragment problems.
 *		Alan Cox	:	General cleanup, comments and reformat
 *		Alan Cox	:	SNMP statistics
 *		Alan Cox	:	BSD address rule semantics. Also see
 *					UDP as there is a nasty checksum issue
 *					if you do things the wrong way.
 *		Alan Cox	:	Always defrag, moved IP_FORWARD to the config.in file
 *		Alan Cox	: 	IP options adjust sk->priority.
 *		Pedro Roque	:	Fix mtu/length error in ip_forward.
 *		Alan Cox	:	Avoid ip_chk_addr when possible.
 *	Richard Underwood	:	IP multicasting.
 *		Alan Cox	:	Cleaned up multicast handlers.
 *		Alan Cox	:	RAW sockets demultiplex in the BSD style.
 *		Gunther Mayer	:	Fix the SNMP reporting typo
 *		Alan Cox	:	Always in group 224.0.0.1
 *	Pauline Middelink	:	Fast ip_checksum update when forwarding
 *					Masquerading support.
 *		Alan Cox	:	Multicast loopback error for 224.0.0.1
 *		Alan Cox	:	IP_MULTICAST_LOOP option.
 *		Alan Cox	:	Use notifiers.
 *		Bjorn Ekwall	:	Removed ip_csum (from slhc.c too)
 *		Bjorn Ekwall	:	Moved ip_fast_csum to ip.h (inline!)
 *		Stefan Becker   :       Send out ICMP HOST REDIRECT
 *	Arnt Gulbrandsen	:	ip_build_xmit
 *		Alan Cox	:	Per socket routing cache
 *		Alan Cox	:	Fixed routing cache, added header cache.
 *		Alan Cox	:	Loopback didn't work right in original ip_build_xmit - fixed it.
 *		Alan Cox	:	Only send ICMP_REDIRECT if src/dest are the same net.
 *		Alan Cox	:	Incoming IP option handling.
 *		Alan Cox	:	Set saddr on raw output frames as per BSD.
 *		Alan Cox	:	Stopped broadcast source route explosions.
 *		Alan Cox	:	Can disable source routing
 *		Takeshi Sone    :	Masquerading didn't work.
 *	Dave Bonn,Alan Cox	:	Faster IP forwarding whenever possible.
 *		Alan Cox	:	Memory leaks, tramples, misc debugging.
 *		Alan Cox	:	Fixed multicast (by popular demand 8))
 *		Alan Cox	:	Fixed forwarding (by even more popular demand 8))
 *		Alan Cox	:	Fixed SNMP statistics [I think]
 *	Gerhard Koerting	:	IP fragmentation forwarding fix
 *		Alan Cox	:	Device lock against page fault.
 *		Alan Cox	:	IP_HDRINCL facility.
 *	Werner Almesberger	:	Zero fragment bug
 *		Alan Cox	:	RAW IP frame length bug
 *		Alan Cox	:	Outgoing firewall on build_xmit
 *		A.N.Kuznetsov	:	IP_OPTIONS support throughout the kernel
 *		Alan Cox	:	Multicast routing hooks
 *		Jos Vos		:	Do accounting *before* call_in_firewall
 *	Willy Konynenberg	:	Transparent proxying support
 *
 *  
 *
 * To Fix:
 *		IP fragmentation wants rewriting cleanly. The RFC815 algorithm is much more efficient
 *		and could be made very efficient with the addition of some virtual memory hacks to permit
 *		the allocation of a buffer that can then be 'grown' by twiddling page tables.
 *		Output fragmentation wants updating along with the buffer management to use a single 
 *		interleaved copy algorithm so that fragmenting has a one copy overhead. Actual packet
 *		output should probably do its own fragmentation at the UDP/RAW layer. TCP shouldn't cause
 *		fragmentation anyway.
 *
 *		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.
 */

#include <asm/system.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/config.h>

#include <linux/net.h>
#include <linux/socket.h>
#include <linux/sockios.h>
#include <linux/in.h>
#include <linux/inet.h>
#include <linux/inetdevice.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>

#include <net/snmp.h>
#include <net/ip.h>
#include <net/protocol.h>
#include <net/route.h>
#include <linux/skbuff.h>
#include <net/sock.h>
#include <net/arp.h>
#include <net/icmp.h>
#include <net/raw.h>
#include <net/checksum.h>
#include <linux/netfilter_ipv4.h>
#include <net/xfrm.h>
#include <linux/mroute.h>
#include <linux/netlink.h>

/*
 *	SNMP management statistics
 */

DEFINE_SNMP_STAT(struct ipstats_mib, ip_statistics) __read_mostly;

/*
 *	Process Router Attention IP option
 */ 
int ip_call_ra_chain(struct sk_buff *skb)
{
	struct ip_ra_chain *ra;
	u8 protocol = skb->nh.iph->protocol;
	struct sock *last = NULL;

	read_lock(&ip_ra_lock);
	for (ra = ip_ra_chain; ra; ra = ra->next) {
		struct sock *sk = ra->sk;

		/* If socket is bound to an interface, only report
		 * the packet if it came  from that interface.
		 */
		if (sk && inet_sk(sk)->num == protocol &&
		    (!sk->sk_bound_dev_if ||
		     sk->sk_bound_dev_if == skb->dev->ifindex)) {
			if (skb->nh.iph->frag_off & htons(IP_MF|IP_OFFSET)) {
				skb = ip_defrag(skb, IP_DEFRAG_CALL_RA_CHAIN);
				if (skb == NULL) {
					read_unlock(&ip_ra_lock);
					return 1;
				}
			}
			if (last) {
				struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
				if (skb2)
					raw_rcv(last, skb2);
			}
			last = sk;
			nf_reset(skb);
		}
	}

	if (last) {
		raw_rcv(last, skb);
		read_unlock(&ip_ra_lock);
		return 1;
	}
	read_unlock(&ip_ra_lock);
	return 0;
}

static inline int ip_local_deliver_finish(struct sk_buff *skb)
{
	int ihl = skb->nh.iph->ihl*4;

	__skb_pull(skb, ihl);

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

        /* Point into the IP datagram, just past the header. */
        skb->h.raw = skb->data;

	rcu_read_lock();
	{
		/* Note: See raw.c and net/raw.h, RAWV4_HTABLE_SIZE==MAX_INET_PROTOS */
		int protocol = skb->nh.iph->protocol;
		int hash;
		struct sock *raw_sk;
		struct net_protocol *ipprot;

	resubmit:
		hash = protocol & (MAX_INET_PROTOS - 1);
		raw_sk = sk_head(&raw_v4_htable[hash]);

		/* If there maybe a raw socket we must check - if not we
		 * don't care less
		 */
		if (raw_sk && !raw_v4_input(skb, skb->nh.iph, hash))
			raw_sk = NULL;

		if ((ipprot = rcu_dereference(inet_protos[hash])) != NULL) {
			int ret;

			if (!ipprot->no_policy &&
			    !xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
				kfree_skb(skb);
				goto out;
			}
			ret = ipprot->handler(skb);
			if (ret < 0) {
				protocol = -ret;
				goto resubmit;
			}
			IP_INC_STATS_BH(IPSTATS_MIB_INDELIVERS);
		} else {
			if (!raw_sk) {
				if (xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
					IP_INC_STATS_BH(IPSTATS_MIB_INUNKNOWNPROTOS);
					icmp_send(skb, ICMP_DEST_UNREACH,
						  ICMP_PROT_UNREACH, 0);
				}
			} else
				IP_INC_STATS_BH(IPSTATS_MIB_INDELIVERS);
			kfree_skb(skb);
		}
	}
 out:
	rcu_read_unlock();

	return 0;
}

/*
 * 	Deliver IP Packets to the higher protocol layers.
 */ 
int ip_local_deliver(struct sk_buff *skb)
{
	/*
	 *	Reassemble IP fragments.
	 */

	if (skb->nh.iph->frag_off & htons(IP_MF|IP_OFFSET)) {
		skb = ip_defrag(skb, IP_DEFRAG_LOCAL_DELIVER);
		if (!skb)
			return 0;
	}

	return NF_HOOK(PF_INET, NF_IP_LOCAL_IN, skb, skb->dev, NULL,
		       ip_local_deliver_finish);
}

static inline int ip_rcv_options(struct sk_buff *skb)
{
	struct ip_options *opt;
	struct iphdr *iph;
	struct net_device *dev = skb->dev;

	/* It looks as overkill, because not all
	   IP options require packet mangling.
	   But it is the easiest for now, especially taking
	   into account that combination of IP options
	   and running sniffer is extremely rare condition.
					      --ANK (980813)
	*/
	if (skb_cow(skb, skb_headroom(skb))) {
		IP_INC_STATS_BH(IPSTATS_MIB_INDISCARDS);
		goto drop;
	}

	iph = skb->nh.iph;

	if (ip_options_compile(NULL, skb)) {
		IP_INC_STATS_BH(IPSTATS_MIB_INHDRERRORS);
		goto drop;
	}

	opt = &(IPCB(skb)->opt);
	if (unlikely(opt->srr)) {
		struct in_device *in_dev = in_dev_get(dev);
		if (in_dev) {
			if (!IN_DEV_SOURCE_ROUTE(in_dev)) {
				if (IN_DEV_LOG_MARTIANS(in_dev) &&
				    net_ratelimit())
					printk(KERN_INFO "source route option "
					       "%u.%u.%u.%u -> %u.%u.%u.%u\n",
					       NIPQUAD(iph->saddr),
					       NIPQUAD(iph->daddr));
				in_dev_put(in_dev);
				goto drop;
			}

			in_dev_put(in_dev);
		}

		if (ip_options_rcv_srr(skb))
			goto drop;
	}

	return 0;
drop:
	return -1;
}

static inline int ip_rcv_finish(struct sk_buff *skb)
{
	struct iphdr *iph = skb->nh.iph;

	/*
	 *	Initialise the virtual path cache for the packet. It describes
	 *	how the packet travels inside Linux networking.
	 */ 
	if (likely(skb->dst == NULL)) {
		int err = ip_route_input(skb, iph->daddr, iph->saddr, iph->tos,
					 skb->dev);
		if (unlikely(err)) {
			if (err == -EHOSTUNREACH)
				IP_INC_STATS_BH(IPSTATS_MIB_INADDRERRORS);
			goto drop; 
		}
	}

#ifdef CONFIG_NET_CLS_ROUTE
	if (unlikely(skb->dst->tclassid)) {
		struct ip_rt_acct *st = ip_rt_acct + 256*smp_processor_id();
		u32 idx = skb->dst->tclassid;
		st[idx&0xFF].o_packets++;
		st[idx&0xFF].o_bytes+=skb->len;
		st[(idx>>16)&0xFF].i_packets++;
		st[(idx>>16)&0xFF].i_bytes+=skb->len;
	}
#endif

	if (iph->ihl > 5 && ip_rcv_options(skb))
		goto drop;

	return dst_input(skb);

drop:
        kfree_skb(skb);
        return NET_RX_DROP;
}

/*
 * 	Main IP Receive routine.
 */ 
int ip_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, struct net_device *orig_dev)
{
	struct iphdr *iph;
	u32 len;

	/* When the interface is in promisc. mode, drop all the crap
	 * that it receives, do not try to analyse it.
	 */
	if (skb->pkt_type == PACKET_OTHERHOST)
		goto drop;

	IP_INC_STATS_BH(IPSTATS_MIB_INRECEIVES);

	if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL) {
		IP_INC_STATS_BH(IPSTATS_MIB_INDISCARDS);
		goto out;
	}

	if (!pskb_may_pull(skb, sizeof(struct iphdr)))
		goto inhdr_error;

	iph = skb->nh.iph;

	/*
	 *	RFC1122: 3.1.2.2 MUST silently discard any IP frame that fails the checksum.
	 *
	 *	Is the datagram acceptable?
	 *
	 *	1.	Length at least the size of an ip header
	 *	2.	Version of 4
	 *	3.	Checksums correctly. [Speed optimisation for later, skip loopback checksums]
	 *	4.	Doesn't have a bogus length
	 */

	if (iph->ihl < 5 || iph->version != 4)
		goto inhdr_error;

	if (!pskb_may_pull(skb, iph->ihl*4))
		goto inhdr_error;

	iph = skb->nh.iph;

	if (unlikely(ip_fast_csum((u8 *)iph, iph->ihl)))
		goto inhdr_error;

	len = ntohs(iph->tot_len);
	if (skb->len < len || len < (iph->ihl*4))
		goto inhdr_error;

	/* Our transport medium may have padded the buffer out. Now we know it
	 * is IP we can trim to the true length of the frame.
	 * Note this now means skb->len holds ntohs(iph->tot_len).
	 */
	if (pskb_trim_rcsum(skb, len)) {
		IP_INC_STATS_BH(IPSTATS_MIB_INDISCARDS);
		goto drop;
	}

	return NF_HOOK(PF_INET, NF_IP_PRE_ROUTING, skb, dev, NULL,
		       ip_rcv_finish);

inhdr_error:
	IP_INC_STATS_BH(IPSTATS_MIB_INHDRERRORS);
drop:
        kfree_skb(skb);
out:
        return NET_RX_DROP;
}

EXPORT_SYMBOL(ip_statistics);
Commit	Line	Data
1da177e4 LT	1	/*
	2	* INET An implementation of the TCP/IP protocol suite for the LINUX
	3	* operating system. INET is implemented using the BSD Socket
	4	* interface as the means of communication with the user level.
	5	*
	6	* The Internet Protocol (IP) module.
	7	*
	8	* Version: $Id: ip_input.c,v 1.55 2002/01/12 07:39:45 davem Exp $
	9	*
02c30a84	10	* Authors: Ross Biro
1da177e4 LT	11	* Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
	12	* Donald Becker, <becker@super.org>
	13	* Alan Cox, <Alan.Cox@linux.org>
	14	* Richard Underwood
	15	* Stefan Becker, <stefanb@yello.ping.de>
	16	* Jorge Cwik, <jorge@laser.satlink.net>
	17	* Arnt Gulbrandsen, <agulbra@nvg.unit.no>
	18	*
	19	*
	20	* Fixes:
	21	* Alan Cox : Commented a couple of minor bits of surplus code
	22	* Alan Cox : Undefining IP_FORWARD doesn't include the code
	23	* (just stops a compiler warning).
	24	* Alan Cox : Frames with >=MAX_ROUTE record routes, strict routes or loose routes
	25	* are junked rather than corrupting things.
	26	* Alan Cox : Frames to bad broadcast subnets are dumped
	27	* We used to process them non broadcast and
	28	* boy could that cause havoc.
	29	* Alan Cox : ip_forward sets the free flag on the
	30	* new frame it queues. Still crap because
	31	* it copies the frame but at least it
	32	* doesn't eat memory too.
	33	* Alan Cox : Generic queue code and memory fixes.
	34	* Fred Van Kempen : IP fragment support (borrowed from NET2E)
	35	* Gerhard Koerting: Forward fragmented frames correctly.
	36	* Gerhard Koerting: Fixes to my fix of the above 8-).
	37	* Gerhard Koerting: IP interface addressing fix.
	38	* Linus Torvalds : More robustness checks
	39	* Alan Cox : Even more checks: Still not as robust as it ought to be
	40	* Alan Cox : Save IP header pointer for later
	41	* Alan Cox : ip option setting
	42	* Alan Cox : Use ip_tos/ip_ttl settings
	43	* Alan Cox : Fragmentation bogosity removed
	44	* (Thanks to Mark.Bush@prg.ox.ac.uk)
	45	* Dmitry Gorodchanin : Send of a raw packet crash fix.
	46	* Alan Cox : Silly ip bug when an overlength
	47	* fragment turns up. Now frees the
	48	* queue.
	49	* Linus Torvalds/ : Memory leakage on fragmentation
	50	* Alan Cox : handling.
	51	* Gerhard Koerting: Forwarding uses IP priority hints
	52	* Teemu Rantanen : Fragment problems.
	53	* Alan Cox : General cleanup, comments and reformat
	54	* Alan Cox : SNMP statistics
	55	* Alan Cox : BSD address rule semantics. Also see
	56	* UDP as there is a nasty checksum issue
	57	* if you do things the wrong way.
	58	* Alan Cox : Always defrag, moved IP_FORWARD to the config.in file
	59	* Alan Cox : IP options adjust sk->priority.
	60	* Pedro Roque : Fix mtu/length error in ip_forward.
	61	* Alan Cox : Avoid ip_chk_addr when possible.
	62	* Richard Underwood : IP multicasting.
	63	* Alan Cox : Cleaned up multicast handlers.
	64	* Alan Cox : RAW sockets demultiplex in the BSD style.
	65	* Gunther Mayer : Fix the SNMP reporting typo
	66	* Alan Cox : Always in group 224.0.0.1
	67	* Pauline Middelink : Fast ip_checksum update when forwarding
	68	* Masquerading support.
	69	* Alan Cox : Multicast loopback error for 224.0.0.1
	70	* Alan Cox : IP_MULTICAST_LOOP option.
	71	* Alan Cox : Use notifiers.
	72	* Bjorn Ekwall : Removed ip_csum (from slhc.c too)
	73	* Bjorn Ekwall : Moved ip_fast_csum to ip.h (inline!)
	74	* Stefan Becker : Send out ICMP HOST REDIRECT
75	* Arnt Gulbrandsen : ip_build_xmit
76	* Alan Cox : Per socket routing cache
77	* Alan Cox : Fixed routing cache, added header cache.
78	* Alan Cox : Loopback didn't work right in original ip_build_xmit - fixed it.
79	* Alan Cox : Only send ICMP_REDIRECT if src/dest are the same net.
80	* Alan Cox : Incoming IP option handling.
81	* Alan Cox : Set saddr on raw output frames as per BSD.
82	* Alan Cox : Stopped broadcast source route explosions.
83	* Alan Cox : Can disable source routing
84	* Takeshi Sone : Masquerading didn't work.
85	* Dave Bonn,Alan Cox : Faster IP forwarding whenever possible.
86	* Alan Cox : Memory leaks, tramples, misc debugging.
87	* Alan Cox : Fixed multicast (by popular demand 8))
88	* Alan Cox : Fixed forwarding (by even more popular demand 8))
89	* Alan Cox : Fixed SNMP statistics [I think]
90	* Gerhard Koerting : IP fragmentation forwarding fix
91	* Alan Cox : Device lock against page fault.
92	* Alan Cox : IP_HDRINCL facility.
93	* Werner Almesberger : Zero fragment bug
94	* Alan Cox : RAW IP frame length bug
95	* Alan Cox : Outgoing firewall on build_xmit
96	* A.N.Kuznetsov : IP_OPTIONS support throughout the kernel
97	* Alan Cox : Multicast routing hooks
98	* Jos Vos : Do accounting before call_in_firewall
99	* Willy Konynenberg : Transparent proxying support
100	*
101	*
102	*
103	* To Fix:
104	* IP fragmentation wants rewriting cleanly. The RFC815 algorithm is much more efficient
105	* and could be made very efficient with the addition of some virtual memory hacks to permit
106	* the allocation of a buffer that can then be 'grown' by twiddling page tables.
107	* Output fragmentation wants updating along with the buffer management to use a single
108	* interleaved copy algorithm so that fragmenting has a one copy overhead. Actual packet
109	* output should probably do its own fragmentation at the UDP/RAW layer. TCP shouldn't cause
110	* fragmentation anyway.
111	*
112	* This program is free software; you can redistribute it and/or
113	* modify it under the terms of the GNU General Public License
114	* as published by the Free Software Foundation; either version
115	* 2 of the License, or (at your option) any later version.
116	*/
117
118	#include <asm/system.h>
119	#include <linux/module.h>
120	#include <linux/types.h>
121	#include <linux/kernel.h>
122	#include <linux/string.h>
123	#include <linux/errno.h>
124	#include <linux/config.h>
125
126	#include <linux/net.h>
127	#include <linux/socket.h>
128	#include <linux/sockios.h>
129	#include <linux/in.h>
130	#include <linux/inet.h>
14c85021	131	#include <linux/inetdevice.h>
1da177e4 LT	132	#include <linux/netdevice.h>
	133	#include <linux/etherdevice.h>
	134
	135	#include <net/snmp.h>
	136	#include <net/ip.h>
	137	#include <net/protocol.h>
	138	#include <net/route.h>
	139	#include <linux/skbuff.h>
	140	#include <net/sock.h>
	141	#include <net/arp.h>
	142	#include <net/icmp.h>
	143	#include <net/raw.h>
	144	#include <net/checksum.h>
	145	#include <linux/netfilter_ipv4.h>
	146	#include <net/xfrm.h>
	147	#include <linux/mroute.h>
	148	#include <linux/netlink.h>
	149
	150	/*
	151	* SNMP management statistics
	152	*/
	153
ba89966c	154	DEFINE_SNMP_STAT(struct ipstats_mib, ip_statistics) __read_mostly;
1da177e4 LT	155
	156	/*
	157	* Process Router Attention IP option
	158	*/
	159	int ip_call_ra_chain(struct sk_buff *skb)
	160	{
	161	struct ip_ra_chain *ra;
	162	u8 protocol = skb->nh.iph->protocol;
	163	struct sock *last = NULL;
	164
	165	read_lock(&ip_ra_lock);
	166	for (ra = ip_ra_chain; ra; ra = ra->next) {
	167	struct sock *sk = ra->sk;
	168
	169	/* If socket is bound to an interface, only report
	170	* the packet if it came from that interface.
	171	*/
	172	if (sk && inet_sk(sk)->num == protocol &&
	173	(!sk->sk_bound_dev_if \|\|
	174	sk->sk_bound_dev_if == skb->dev->ifindex)) {
	175	if (skb->nh.iph->frag_off & htons(IP_MF\|IP_OFFSET)) {
	176	skb = ip_defrag(skb, IP_DEFRAG_CALL_RA_CHAIN);
	177	if (skb == NULL) {
	178	read_unlock(&ip_ra_lock);
	179	return 1;
	180	}
	181	}
	182	if (last) {
	183	struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
	184	if (skb2)
	185	raw_rcv(last, skb2);
	186	}
	187	last = sk;
2715bcf9	188	nf_reset(skb);
1da177e4 LT	189	}
	190	}
	191
	192	if (last) {
	193	raw_rcv(last, skb);
	194	read_unlock(&ip_ra_lock);
	195	return 1;
	196	}
	197	read_unlock(&ip_ra_lock);
	198	return 0;
	199	}
	200
	201	static inline int ip_local_deliver_finish(struct sk_buff *skb)
	202	{
	203	int ihl = skb->nh.iph->ihl*4;
	204
1da177e4 LT	205	__skb_pull(skb, ihl);
	206
	207	/* Free reference early: we don't need it any more, and it may
	208	hold ip_conntrack module loaded indefinitely. */
	209	nf_reset(skb);
	210
	211	/* Point into the IP datagram, just past the header. */
	212	skb->h.raw = skb->data;
	213
	214	rcu_read_lock();
	215	{
	216	/* Note: See raw.c and net/raw.h, RAWV4_HTABLE_SIZE==MAX_INET_PROTOS */
	217	int protocol = skb->nh.iph->protocol;
	218	int hash;
	219	struct sock *raw_sk;
	220	struct net_protocol *ipprot;
	221
	222	resubmit:
	223	hash = protocol & (MAX_INET_PROTOS - 1);
	224	raw_sk = sk_head(&raw_v4_htable[hash]);
	225
	226	/* If there maybe a raw socket we must check - if not we
	227	* don't care less
	228	*/
d13964f4 PM	229	if (raw_sk && !raw_v4_input(skb, skb->nh.iph, hash))
d13964f4 PM	230	raw_sk = NULL;
1da177e4 LT	231
	232	if ((ipprot = rcu_dereference(inet_protos[hash])) != NULL) {
	233	int ret;
	234
	235	if (!ipprot->no_policy &&
	236	!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
	237	kfree_skb(skb);
	238	goto out;
	239	}
	240	ret = ipprot->handler(skb);
	241	if (ret < 0) {
	242	protocol = -ret;
	243	goto resubmit;
	244	}
	245	IP_INC_STATS_BH(IPSTATS_MIB_INDELIVERS);
	246	} else {
	247	if (!raw_sk) {
	248	if (xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
	249	IP_INC_STATS_BH(IPSTATS_MIB_INUNKNOWNPROTOS);
	250	icmp_send(skb, ICMP_DEST_UNREACH,
	251	ICMP_PROT_UNREACH, 0);
	252	}
	253	} else
	254	IP_INC_STATS_BH(IPSTATS_MIB_INDELIVERS);
	255	kfree_skb(skb);
	256	}
	257	}
	258	out:
	259	rcu_read_unlock();
	260
	261	return 0;
	262	}
	263
	264	/*
	265	* Deliver IP Packets to the higher protocol layers.
	266	*/
	267	int ip_local_deliver(struct sk_buff *skb)
	268	{
	269	/*
	270	* Reassemble IP fragments.
	271	*/
	272
	273	if (skb->nh.iph->frag_off & htons(IP_MF\|IP_OFFSET)) {
	274	skb = ip_defrag(skb, IP_DEFRAG_LOCAL_DELIVER);
	275	if (!skb)
	276	return 0;
	277	}
	278
	279	return NF_HOOK(PF_INET, NF_IP_LOCAL_IN, skb, skb->dev, NULL,
	280	ip_local_deliver_finish);
	281	}
	282
d245407e TG	283	static inline int ip_rcv_options(struct sk_buff *skb)
	284	{
	285	struct ip_options *opt;
	286	struct iphdr *iph;
	287	struct net_device *dev = skb->dev;
	288
	289	/* It looks as overkill, because not all
	290	IP options require packet mangling.
	291	But it is the easiest for now, especially taking
	292	into account that combination of IP options
	293	and running sniffer is extremely rare condition.
	294	--ANK (980813)
	295	*/
	296	if (skb_cow(skb, skb_headroom(skb))) {
	297	IP_INC_STATS_BH(IPSTATS_MIB_INDISCARDS);
	298	goto drop;
	299	}
	300
	301	iph = skb->nh.iph;
	302
	303	if (ip_options_compile(NULL, skb)) {
	304	IP_INC_STATS_BH(IPSTATS_MIB_INHDRERRORS);
	305	goto drop;
	306	}
	307
	308	opt = &(IPCB(skb)->opt);
	309	if (unlikely(opt->srr)) {
	310	struct in_device *in_dev = in_dev_get(dev);
	311	if (in_dev) {
	312	if (!IN_DEV_SOURCE_ROUTE(in_dev)) {
	313	if (IN_DEV_LOG_MARTIANS(in_dev) &&
	314	net_ratelimit())
	315	printk(KERN_INFO "source route option "
	316	"%u.%u.%u.%u -> %u.%u.%u.%u\n",
	317	NIPQUAD(iph->saddr),
	318	NIPQUAD(iph->daddr));
	319	in_dev_put(in_dev);
	320	goto drop;
	321	}
	322
	323	in_dev_put(in_dev);
	324	}
	325
	326	if (ip_options_rcv_srr(skb))
	327	goto drop;
	328	}
	329
	330	return 0;
	331	drop:
	332	return -1;
	333	}
	334
1da177e4 LT	335	static inline int ip_rcv_finish(struct sk_buff *skb)
1da177e4 LT	336	{
1da177e4 LT	337	struct iphdr *iph = skb->nh.iph;
	338
	339	/*
	340	* Initialise the virtual path cache for the packet. It describes
	341	* how the packet travels inside Linux networking.
	342	*/
3e192bea TG	343	if (likely(skb->dst == NULL)) {
	344	int err = ip_route_input(skb, iph->daddr, iph->saddr, iph->tos,
	345	skb->dev);
	346	if (unlikely(err)) {
2c2910a4 DE	347	if (err == -EHOSTUNREACH)
2c2910a4 DE	348	IP_INC_STATS_BH(IPSTATS_MIB_INADDRERRORS);
1da177e4	349	goto drop;
2c2910a4	350	}
1da177e4 LT	351	}
	352
	353	#ifdef CONFIG_NET_CLS_ROUTE
3e192bea	354	if (unlikely(skb->dst->tclassid)) {
1da177e4 LT	355	struct ip_rt_acct st = ip_rt_acct + 256smp_processor_id();
	356	u32 idx = skb->dst->tclassid;
	357	st[idx&0xFF].o_packets++;
	358	st[idx&0xFF].o_bytes+=skb->len;
	359	st[(idx>>16)&0xFF].i_packets++;
	360	st[(idx>>16)&0xFF].i_bytes+=skb->len;
	361	}
	362	#endif
	363
d245407e TG	364	if (iph->ihl > 5 && ip_rcv_options(skb))
d245407e TG	365	goto drop;
1da177e4 LT	366
	367	return dst_input(skb);
	368
1da177e4 LT	369	drop:
	370	kfree_skb(skb);
	371	return NET_RX_DROP;
	372	}
	373
	374	/*
	375	* Main IP Receive routine.
	376	*/
f2ccd8fa	377	int ip_rcv(struct sk_buff skb, struct net_device dev, struct packet_type pt, struct net_device orig_dev)
1da177e4 LT	378	{
1da177e4 LT	379	struct iphdr *iph;
58615242	380	u32 len;
1da177e4 LT	381
	382	/* When the interface is in promisc. mode, drop all the crap
	383	* that it receives, do not try to analyse it.
	384	*/
	385	if (skb->pkt_type == PACKET_OTHERHOST)
	386	goto drop;
	387
	388	IP_INC_STATS_BH(IPSTATS_MIB_INRECEIVES);
	389
	390	if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL) {
	391	IP_INC_STATS_BH(IPSTATS_MIB_INDISCARDS);
	392	goto out;
	393	}
	394
	395	if (!pskb_may_pull(skb, sizeof(struct iphdr)))
	396	goto inhdr_error;
	397
	398	iph = skb->nh.iph;
	399
	400	/*
	401	* RFC1122: 3.1.2.2 MUST silently discard any IP frame that fails the checksum.
	402	*
	403	* Is the datagram acceptable?
	404	*
	405	* 1. Length at least the size of an ip header
	406	* 2. Version of 4
	407	* 3. Checksums correctly. [Speed optimisation for later, skip loopback checksums]
	408	* 4. Doesn't have a bogus length
	409	*/
	410
	411	if (iph->ihl < 5 \|\| iph->version != 4)
58615242	412	goto inhdr_error;
1da177e4 LT	413
	414	if (!pskb_may_pull(skb, iph->ihl*4))
	415	goto inhdr_error;
	416
	417	iph = skb->nh.iph;
	418
e9c60422	419	if (unlikely(ip_fast_csum((u8 *)iph, iph->ihl)))
58615242	420	goto inhdr_error;
1da177e4	421
58615242 TG	422	len = ntohs(iph->tot_len);
	423	if (skb->len < len \|\| len < (iph->ihl*4))
	424	goto inhdr_error;
1da177e4	425
58615242 TG	426	/* Our transport medium may have padded the buffer out. Now we know it
	427	* is IP we can trim to the true length of the frame.
	428	* Note this now means skb->len holds ntohs(iph->tot_len).
	429	*/
	430	if (pskb_trim_rcsum(skb, len)) {
	431	IP_INC_STATS_BH(IPSTATS_MIB_INDISCARDS);
	432	goto drop;
1da177e4 LT	433	}
	434
	435	return NF_HOOK(PF_INET, NF_IP_PRE_ROUTING, skb, dev, NULL,
	436	ip_rcv_finish);
	437
	438	inhdr_error:
	439	IP_INC_STATS_BH(IPSTATS_MIB_INHDRERRORS);
	440	drop:
	441	kfree_skb(skb);
	442	out:
	443	return NET_RX_DROP;
	444	}
	445
1da177e4	446	EXPORT_SYMBOL(ip_statistics);