route.c 75.1 KB
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/*
 * 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.
 *
 *		ROUTE - implementation of the IP router.
 *
 * Version:	$Id: route.c,v 1.103 2002/01/12 07:44:09 davem Exp $
 *
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 * Authors:	Ross Biro
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 *		Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
 *		Alan Cox, <gw4pts@gw4pts.ampr.org>
 *		Linus Torvalds, <Linus.Torvalds@helsinki.fi>
 *		Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
 *
 * Fixes:
 *		Alan Cox	:	Verify area fixes.
 *		Alan Cox	:	cli() protects routing changes
 *		Rui Oliveira	:	ICMP routing table updates
 *		(rco@di.uminho.pt)	Routing table insertion and update
 *		Linus Torvalds	:	Rewrote bits to be sensible
 *		Alan Cox	:	Added BSD route gw semantics
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 *		Alan Cox	:	Super /proc >4K
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 *		Alan Cox	:	MTU in route table
 *		Alan Cox	: 	MSS actually. Also added the window
 *					clamper.
 *		Sam Lantinga	:	Fixed route matching in rt_del()
 *		Alan Cox	:	Routing cache support.
 *		Alan Cox	:	Removed compatibility cruft.
 *		Alan Cox	:	RTF_REJECT support.
 *		Alan Cox	:	TCP irtt support.
 *		Jonathan Naylor	:	Added Metric support.
 *	Miquel van Smoorenburg	:	BSD API fixes.
 *	Miquel van Smoorenburg	:	Metrics.
 *		Alan Cox	:	Use __u32 properly
 *		Alan Cox	:	Aligned routing errors more closely with BSD
 *					our system is still very different.
 *		Alan Cox	:	Faster /proc handling
 *	Alexey Kuznetsov	:	Massive rework to support tree based routing,
 *					routing caches and better behaviour.
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 *
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 *		Olaf Erb	:	irtt wasn't being copied right.
 *		Bjorn Ekwall	:	Kerneld route support.
 *		Alan Cox	:	Multicast fixed (I hope)
 * 		Pavel Krauz	:	Limited broadcast fixed
 *		Mike McLagan	:	Routing by source
 *	Alexey Kuznetsov	:	End of old history. Split to fib.c and
 *					route.c and rewritten from scratch.
 *		Andi Kleen	:	Load-limit warning messages.
 *	Vitaly E. Lavrov	:	Transparent proxy revived after year coma.
 *	Vitaly E. Lavrov	:	Race condition in ip_route_input_slow.
 *	Tobias Ringstrom	:	Uninitialized res.type in ip_route_output_slow.
 *	Vladimir V. Ivanov	:	IP rule info (flowid) is really useful.
 *		Marc Boucher	:	routing by fwmark
 *	Robert Olsson		:	Added rt_cache statistics
 *	Arnaldo C. Melo		:	Convert proc stuff to seq_file
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 *	Eric Dumazet		:	hashed spinlocks and rt_check_expire() fixes.
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 * 	Ilia Sotnikov		:	Ignore TOS on PMTUD and Redirect
 * 	Ilia Sotnikov		:	Removed TOS from hash calculations
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 *
 *		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 <linux/module.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <linux/bitops.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/mm.h>
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#include <linux/bootmem.h>
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#include <linux/string.h>
#include <linux/socket.h>
#include <linux/sockios.h>
#include <linux/errno.h>
#include <linux/in.h>
#include <linux/inet.h>
#include <linux/netdevice.h>
#include <linux/proc_fs.h>
#include <linux/init.h>
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#include <linux/workqueue.h>
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#include <linux/skbuff.h>
#include <linux/inetdevice.h>
#include <linux/igmp.h>
#include <linux/pkt_sched.h>
#include <linux/mroute.h>
#include <linux/netfilter_ipv4.h>
#include <linux/random.h>
#include <linux/jhash.h>
#include <linux/rcupdate.h>
#include <linux/times.h>
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#include <net/dst.h>
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#include <net/net_namespace.h>
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#include <net/protocol.h>
#include <net/ip.h>
#include <net/route.h>
#include <net/inetpeer.h>
#include <net/sock.h>
#include <net/ip_fib.h>
#include <net/arp.h>
#include <net/tcp.h>
#include <net/icmp.h>
#include <net/xfrm.h>
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#include <net/netevent.h>
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#include <net/rtnetlink.h>
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#ifdef CONFIG_SYSCTL
#include <linux/sysctl.h>
#endif

#define RT_FL_TOS(oldflp) \
    ((u32)(oldflp->fl4_tos & (IPTOS_RT_MASK | RTO_ONLINK)))

#define IP_MAX_MTU	0xFFF0

#define RT_GC_TIMEOUT (300*HZ)

static int ip_rt_max_size;
static int ip_rt_gc_timeout		= RT_GC_TIMEOUT;
static int ip_rt_gc_interval		= 60 * HZ;
static int ip_rt_gc_min_interval	= HZ / 2;
static int ip_rt_redirect_number	= 9;
static int ip_rt_redirect_load		= HZ / 50;
static int ip_rt_redirect_silence	= ((HZ / 50) << (9 + 1));
static int ip_rt_error_cost		= HZ;
static int ip_rt_error_burst		= 5 * HZ;
static int ip_rt_gc_elasticity		= 8;
static int ip_rt_mtu_expires		= 10 * 60 * HZ;
static int ip_rt_min_pmtu		= 512 + 20 + 20;
static int ip_rt_min_advmss		= 256;
static int ip_rt_secret_interval	= 10 * 60 * HZ;

#define RTprint(a...)	printk(KERN_DEBUG a)

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static void rt_worker_func(struct work_struct *work);
static DECLARE_DELAYED_WORK(expires_work, rt_worker_func);
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static struct timer_list rt_secret_timer;

/*
 *	Interface to generic destination cache.
 */

static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie);
static void		 ipv4_dst_destroy(struct dst_entry *dst);
static void		 ipv4_dst_ifdown(struct dst_entry *dst,
					 struct net_device *dev, int how);
static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst);
static void		 ipv4_link_failure(struct sk_buff *skb);
static void		 ip_rt_update_pmtu(struct dst_entry *dst, u32 mtu);
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static int rt_garbage_collect(struct dst_ops *ops);
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static struct dst_ops ipv4_dst_ops = {
	.family =		AF_INET,
	.protocol =		__constant_htons(ETH_P_IP),
	.gc =			rt_garbage_collect,
	.check =		ipv4_dst_check,
	.destroy =		ipv4_dst_destroy,
	.ifdown =		ipv4_dst_ifdown,
	.negative_advice =	ipv4_negative_advice,
	.link_failure =		ipv4_link_failure,
	.update_pmtu =		ip_rt_update_pmtu,
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	.local_out =		ip_local_out,
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	.entry_size =		sizeof(struct rtable),
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	.entries =		ATOMIC_INIT(0),
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};

#define ECN_OR_COST(class)	TC_PRIO_##class

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const __u8 ip_tos2prio[16] = {
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	TC_PRIO_BESTEFFORT,
	ECN_OR_COST(FILLER),
	TC_PRIO_BESTEFFORT,
	ECN_OR_COST(BESTEFFORT),
	TC_PRIO_BULK,
	ECN_OR_COST(BULK),
	TC_PRIO_BULK,
	ECN_OR_COST(BULK),
	TC_PRIO_INTERACTIVE,
	ECN_OR_COST(INTERACTIVE),
	TC_PRIO_INTERACTIVE,
	ECN_OR_COST(INTERACTIVE),
	TC_PRIO_INTERACTIVE_BULK,
	ECN_OR_COST(INTERACTIVE_BULK),
	TC_PRIO_INTERACTIVE_BULK,
	ECN_OR_COST(INTERACTIVE_BULK)
};


/*
 * Route cache.
 */

/* The locking scheme is rather straight forward:
 *
 * 1) Read-Copy Update protects the buckets of the central route hash.
 * 2) Only writers remove entries, and they hold the lock
 *    as they look at rtable reference counts.
 * 3) Only readers acquire references to rtable entries,
 *    they do so with atomic increments and with the
 *    lock held.
 */

struct rt_hash_bucket {
	struct rtable	*chain;
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};
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#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) || \
	defined(CONFIG_PROVE_LOCKING)
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/*
 * Instead of using one spinlock for each rt_hash_bucket, we use a table of spinlocks
 * The size of this table is a power of two and depends on the number of CPUS.
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 * (on lockdep we have a quite big spinlock_t, so keep the size down there)
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 */
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#ifdef CONFIG_LOCKDEP
# define RT_HASH_LOCK_SZ	256
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#else
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# if NR_CPUS >= 32
#  define RT_HASH_LOCK_SZ	4096
# elif NR_CPUS >= 16
#  define RT_HASH_LOCK_SZ	2048
# elif NR_CPUS >= 8
#  define RT_HASH_LOCK_SZ	1024
# elif NR_CPUS >= 4
#  define RT_HASH_LOCK_SZ	512
# else
#  define RT_HASH_LOCK_SZ	256
# endif
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#endif

static spinlock_t	*rt_hash_locks;
# define rt_hash_lock_addr(slot) &rt_hash_locks[(slot) & (RT_HASH_LOCK_SZ - 1)]
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static __init void rt_hash_lock_init(void)
{
	int i;

	rt_hash_locks = kmalloc(sizeof(spinlock_t) * RT_HASH_LOCK_SZ,
			GFP_KERNEL);
	if (!rt_hash_locks)
		panic("IP: failed to allocate rt_hash_locks\n");

	for (i = 0; i < RT_HASH_LOCK_SZ; i++)
		spin_lock_init(&rt_hash_locks[i]);
}
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#else
# define rt_hash_lock_addr(slot) NULL
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static inline void rt_hash_lock_init(void)
{
}
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#endif
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static struct rt_hash_bucket 	*rt_hash_table;
static unsigned			rt_hash_mask;
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static unsigned int		rt_hash_log;
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static atomic_t			rt_genid;
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static DEFINE_PER_CPU(struct rt_cache_stat, rt_cache_stat);
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#define RT_CACHE_STAT_INC(field) \
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	(__raw_get_cpu_var(rt_cache_stat).field++)
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static unsigned int rt_hash_code(u32 daddr, u32 saddr)
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{
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	return jhash_2words(daddr, saddr, atomic_read(&rt_genid))
		& rt_hash_mask;
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}

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#define rt_hash(daddr, saddr, idx) \
	rt_hash_code((__force u32)(__be32)(daddr),\
		     (__force u32)(__be32)(saddr) ^ ((idx) << 5))

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#ifdef CONFIG_PROC_FS
struct rt_cache_iter_state {
	int bucket;
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	int genid;
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};

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static struct rtable *rt_cache_get_first(struct rt_cache_iter_state *st)
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{
	struct rtable *r = NULL;

	for (st->bucket = rt_hash_mask; st->bucket >= 0; --st->bucket) {
		rcu_read_lock_bh();
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		r = rcu_dereference(rt_hash_table[st->bucket].chain);
		while (r) {
			if (r->rt_genid == st->genid)
				return r;
			r = rcu_dereference(r->u.dst.rt_next);
		}
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		rcu_read_unlock_bh();
	}
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	return r;
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}

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static struct rtable *__rt_cache_get_next(struct rt_cache_iter_state *st,
					  struct rtable *r)
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{
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	r = r->u.dst.rt_next;
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	while (!r) {
		rcu_read_unlock_bh();
		if (--st->bucket < 0)
			break;
		rcu_read_lock_bh();
		r = rt_hash_table[st->bucket].chain;
	}
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	return rcu_dereference(r);
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}

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static struct rtable *rt_cache_get_next(struct rt_cache_iter_state *st,
					struct rtable *r)
{
	while ((r = __rt_cache_get_next(st, r)) != NULL) {
		if (r->rt_genid == st->genid)
			break;
	}
	return r;
}

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static struct rtable *rt_cache_get_idx(struct rt_cache_iter_state *st, loff_t pos)
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{
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	struct rtable *r = rt_cache_get_first(st);
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	if (r)
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		while (pos && (r = rt_cache_get_next(st, r)))
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			--pos;
	return pos ? NULL : r;
}

static void *rt_cache_seq_start(struct seq_file *seq, loff_t *pos)
{
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	struct rt_cache_iter_state *st = seq->private;

	if (*pos)
		return rt_cache_get_idx(st, *pos - 1);
	st->genid = atomic_read(&rt_genid);
	return SEQ_START_TOKEN;
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}

static void *rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
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	struct rtable *r;
	struct rt_cache_iter_state *st = seq->private;
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	if (v == SEQ_START_TOKEN)
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		r = rt_cache_get_first(st);
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	else
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		r = rt_cache_get_next(st, v);
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	++*pos;
	return r;
}

static void rt_cache_seq_stop(struct seq_file *seq, void *v)
{
	if (v && v != SEQ_START_TOKEN)
		rcu_read_unlock_bh();
}

static int rt_cache_seq_show(struct seq_file *seq, void *v)
{
	if (v == SEQ_START_TOKEN)
		seq_printf(seq, "%-127s\n",
			   "Iface\tDestination\tGateway \tFlags\t\tRefCnt\tUse\t"
			   "Metric\tSource\t\tMTU\tWindow\tIRTT\tTOS\tHHRef\t"
			   "HHUptod\tSpecDst");
	else {
		struct rtable *r = v;
		char temp[256];

		sprintf(temp, "%s\t%08lX\t%08lX\t%8X\t%d\t%u\t%d\t"
			      "%08lX\t%d\t%u\t%u\t%02X\t%d\t%1d\t%08X",
			r->u.dst.dev ? r->u.dst.dev->name : "*",
			(unsigned long)r->rt_dst, (unsigned long)r->rt_gateway,
			r->rt_flags, atomic_read(&r->u.dst.__refcnt),
			r->u.dst.__use, 0, (unsigned long)r->rt_src,
			(dst_metric(&r->u.dst, RTAX_ADVMSS) ?
			     (int)dst_metric(&r->u.dst, RTAX_ADVMSS) + 40 : 0),
			dst_metric(&r->u.dst, RTAX_WINDOW),
			(int)((dst_metric(&r->u.dst, RTAX_RTT) >> 3) +
			      dst_metric(&r->u.dst, RTAX_RTTVAR)),
			r->fl.fl4_tos,
			r->u.dst.hh ? atomic_read(&r->u.dst.hh->hh_refcnt) : -1,
			r->u.dst.hh ? (r->u.dst.hh->hh_output ==
				       dev_queue_xmit) : 0,
			r->rt_spec_dst);
		seq_printf(seq, "%-127s\n", temp);
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	}
	return 0;
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}

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static const struct seq_operations rt_cache_seq_ops = {
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	.start  = rt_cache_seq_start,
	.next   = rt_cache_seq_next,
	.stop   = rt_cache_seq_stop,
	.show   = rt_cache_seq_show,
};

static int rt_cache_seq_open(struct inode *inode, struct file *file)
{
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	return seq_open_private(file, &rt_cache_seq_ops,
			sizeof(struct rt_cache_iter_state));
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}

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static const struct file_operations rt_cache_seq_fops = {
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	.owner	 = THIS_MODULE,
	.open	 = rt_cache_seq_open,
	.read	 = seq_read,
	.llseek	 = seq_lseek,
	.release = seq_release_private,
};


static void *rt_cpu_seq_start(struct seq_file *seq, loff_t *pos)
{
	int cpu;

	if (*pos == 0)
		return SEQ_START_TOKEN;

	for (cpu = *pos-1; cpu < NR_CPUS; ++cpu) {
		if (!cpu_possible(cpu))
			continue;
		*pos = cpu+1;
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		return &per_cpu(rt_cache_stat, cpu);
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	}
	return NULL;
}

static void *rt_cpu_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
	int cpu;

	for (cpu = *pos; cpu < NR_CPUS; ++cpu) {
		if (!cpu_possible(cpu))
			continue;
		*pos = cpu+1;
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		return &per_cpu(rt_cache_stat, cpu);
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	}
	return NULL;
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}

static void rt_cpu_seq_stop(struct seq_file *seq, void *v)
{

}

static int rt_cpu_seq_show(struct seq_file *seq, void *v)
{
	struct rt_cache_stat *st = v;

	if (v == SEQ_START_TOKEN) {
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		seq_printf(seq, "entries  in_hit in_slow_tot in_slow_mc in_no_route in_brd in_martian_dst in_martian_src  out_hit out_slow_tot out_slow_mc  gc_total gc_ignored gc_goal_miss gc_dst_overflow in_hlist_search out_hlist_search\n");
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		return 0;
	}
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	seq_printf(seq,"%08x  %08x %08x %08x %08x %08x %08x %08x "
		   " %08x %08x %08x %08x %08x %08x %08x %08x %08x \n",
		   atomic_read(&ipv4_dst_ops.entries),
		   st->in_hit,
		   st->in_slow_tot,
		   st->in_slow_mc,
		   st->in_no_route,
		   st->in_brd,
		   st->in_martian_dst,
		   st->in_martian_src,

		   st->out_hit,
		   st->out_slow_tot,
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		   st->out_slow_mc,
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		   st->gc_total,
		   st->gc_ignored,
		   st->gc_goal_miss,
		   st->gc_dst_overflow,
		   st->in_hlist_search,
		   st->out_hlist_search
		);
	return 0;
}

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static const struct seq_operations rt_cpu_seq_ops = {
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	.start  = rt_cpu_seq_start,
	.next   = rt_cpu_seq_next,
	.stop   = rt_cpu_seq_stop,
	.show   = rt_cpu_seq_show,
};


static int rt_cpu_seq_open(struct inode *inode, struct file *file)
{
	return seq_open(file, &rt_cpu_seq_ops);
}

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static const struct file_operations rt_cpu_seq_fops = {
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	.owner	 = THIS_MODULE,
	.open	 = rt_cpu_seq_open,
	.read	 = seq_read,
	.llseek	 = seq_lseek,
	.release = seq_release,
};

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#ifdef CONFIG_NET_CLS_ROUTE
static int ip_rt_acct_read(char *buffer, char **start, off_t offset,
			   int length, int *eof, void *data)
{
	unsigned int i;

	if ((offset & 3) || (length & 3))
		return -EIO;

	if (offset >= sizeof(struct ip_rt_acct) * 256) {
		*eof = 1;
		return 0;
	}

	if (offset + length >= sizeof(struct ip_rt_acct) * 256) {
		length = sizeof(struct ip_rt_acct) * 256 - offset;
		*eof = 1;
	}

	offset /= sizeof(u32);

	if (length > 0) {
		u32 *dst = (u32 *) buffer;

		*start = buffer;
		memset(dst, 0, length);

		for_each_possible_cpu(i) {
			unsigned int j;
			u32 *src;

			src = ((u32 *) per_cpu_ptr(ip_rt_acct, i)) + offset;
			for (j = 0; j < length/4; j++)
				dst[j] += src[j];
		}
	}
	return length;
}
#endif
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static __init int ip_rt_proc_init(struct net *net)
{
	struct proc_dir_entry *pde;

	pde = proc_net_fops_create(net, "rt_cache", S_IRUGO,
			&rt_cache_seq_fops);
	if (!pde)
		goto err1;

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	pde = proc_create("rt_cache", S_IRUGO,
			  net->proc_net_stat, &rt_cpu_seq_fops);
555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579
	if (!pde)
		goto err2;

#ifdef CONFIG_NET_CLS_ROUTE
	pde = create_proc_read_entry("rt_acct", 0, net->proc_net,
			ip_rt_acct_read, NULL);
	if (!pde)
		goto err3;
#endif
	return 0;

#ifdef CONFIG_NET_CLS_ROUTE
err3:
	remove_proc_entry("rt_cache", net->proc_net_stat);
#endif
err2:
	remove_proc_entry("rt_cache", net->proc_net);
err1:
	return -ENOMEM;
}
#else
static inline int ip_rt_proc_init(struct net *net)
{
	return 0;
}
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#endif /* CONFIG_PROC_FS */
581

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static __inline__ void rt_free(struct rtable *rt)
{
	call_rcu_bh(&rt->u.dst.rcu_head, dst_rcu_free);
}

static __inline__ void rt_drop(struct rtable *rt)
{
	ip_rt_put(rt);
	call_rcu_bh(&rt->u.dst.rcu_head, dst_rcu_free);
}

static __inline__ int rt_fast_clean(struct rtable *rth)
{
	/* Kill broadcast/multicast entries very aggresively, if they
	   collide in hash table with more useful entries */
	return (rth->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST)) &&
598
		rth->fl.iif && rth->u.dst.rt_next;
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}

static __inline__ int rt_valuable(struct rtable *rth)
{
	return (rth->rt_flags & (RTCF_REDIRECTED | RTCF_NOTIFY)) ||
		rth->u.dst.expires;
}

static int rt_may_expire(struct rtable *rth, unsigned long tmo1, unsigned long tmo2)
{
	unsigned long age;
	int ret = 0;

	if (atomic_read(&rth->u.dst.__refcnt))
		goto out;

	ret = 1;
	if (rth->u.dst.expires &&
	    time_after_eq(jiffies, rth->u.dst.expires))
		goto out;

	age = jiffies - rth->u.dst.lastuse;
	ret = 0;
	if ((age <= tmo1 && !rt_fast_clean(rth)) ||
	    (age <= tmo2 && rt_valuable(rth)))
		goto out;
	ret = 1;
out:	return ret;
}

/* Bits of score are:
 * 31: very valuable
 * 30: not quite useless
 * 29..0: usage counter
 */
static inline u32 rt_score(struct rtable *rt)
{
	u32 score = jiffies - rt->u.dst.lastuse;

	score = ~score & ~(3<<30);

	if (rt_valuable(rt))
		score |= (1<<31);

	if (!rt->fl.iif ||
	    !(rt->rt_flags & (RTCF_BROADCAST|RTCF_MULTICAST|RTCF_LOCAL)))
		score |= (1<<30);

	return score;
}

static inline int compare_keys(struct flowi *fl1, struct flowi *fl2)
{
652 653
	return ((__force u32)((fl1->nl_u.ip4_u.daddr ^ fl2->nl_u.ip4_u.daddr) |
		(fl1->nl_u.ip4_u.saddr ^ fl2->nl_u.ip4_u.saddr)) |
654
		(fl1->mark ^ fl2->mark) |
655 656 657 658
		(*(u16 *)&fl1->nl_u.ip4_u.tos ^
		 *(u16 *)&fl2->nl_u.ip4_u.tos) |
		(fl1->oif ^ fl2->oif) |
		(fl1->iif ^ fl2->iif)) == 0;
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}

661 662 663 664 665
static inline int compare_netns(struct rtable *rt1, struct rtable *rt2)
{
	return rt1->u.dst.dev->nd_net == rt2->u.dst.dev->nd_net;
}

666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695
/*
 * Perform a full scan of hash table and free all entries.
 * Can be called by a softirq or a process.
 * In the later case, we want to be reschedule if necessary
 */
static void rt_do_flush(int process_context)
{
	unsigned int i;
	struct rtable *rth, *next;

	for (i = 0; i <= rt_hash_mask; i++) {
		if (process_context && need_resched())
			cond_resched();
		rth = rt_hash_table[i].chain;
		if (!rth)
			continue;

		spin_lock_bh(rt_hash_lock_addr(i));
		rth = rt_hash_table[i].chain;
		rt_hash_table[i].chain = NULL;
		spin_unlock_bh(rt_hash_lock_addr(i));

		for (; rth; rth = next) {
			next = rth->u.dst.rt_next;
			rt_free(rth);
		}
	}
}

static void rt_check_expire(void)
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{
697 698
	static unsigned int rover;
	unsigned int i = rover, goal;
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	struct rtable *rth, **rthp;
700 701 702 703 704 705
	u64 mult;

	mult = ((u64)ip_rt_gc_interval) << rt_hash_log;
	if (ip_rt_gc_timeout > 1)
		do_div(mult, ip_rt_gc_timeout);
	goal = (unsigned int)mult;
706 707
	if (goal > rt_hash_mask)
		goal = rt_hash_mask + 1;
708
	for (; goal > 0; goal--) {
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		unsigned long tmo = ip_rt_gc_timeout;

		i = (i + 1) & rt_hash_mask;
		rthp = &rt_hash_table[i].chain;

714 715 716
		if (need_resched())
			cond_resched();

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		if (*rthp == NULL)
718
			continue;
719
		spin_lock_bh(rt_hash_lock_addr(i));
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		while ((rth = *rthp) != NULL) {
721 722 723 724 725
			if (rth->rt_genid != atomic_read(&rt_genid)) {
				*rthp = rth->u.dst.rt_next;
				rt_free(rth);
				continue;
			}
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			if (rth->u.dst.expires) {
				/* Entry is expired even if it is in use */
728
				if (time_before_eq(jiffies, rth->u.dst.expires)) {
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					tmo >>= 1;
730
					rthp = &rth->u.dst.rt_next;
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					continue;
				}
			} else if (!rt_may_expire(rth, tmo, ip_rt_gc_timeout)) {
				tmo >>= 1;
735
				rthp = &rth->u.dst.rt_next;
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				continue;
			}

			/* Cleanup aged off entries. */
740
			*rthp = rth->u.dst.rt_next;
741
			rt_free(rth);
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		}
743
		spin_unlock_bh(rt_hash_lock_addr(i));
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	}
	rover = i;
746 747 748 749
}

/*
 * rt_worker_func() is run in process context.
750
 * we call rt_check_expire() to scan part of the hash table
751 752 753
 */
static void rt_worker_func(struct work_struct *work)
{
754
	rt_check_expire();
755
	schedule_delayed_work(&expires_work, ip_rt_gc_interval);
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}

758 759 760 761 762
/*
 * Pertubation of rt_genid by a small quantity [1..256]
 * Using 8 bits of shuffling ensure we can call rt_cache_invalidate()
 * many times (2^24) without giving recent rt_genid.
 * Jenkins hash is strong enough that litle changes of rt_genid are OK.
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 */
764
static void rt_cache_invalidate(void)
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{
766
	unsigned char shuffle;
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768 769
	get_random_bytes(&shuffle, sizeof(shuffle));
	atomic_add(shuffle + 1U, &rt_genid);
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}

772 773 774 775
/*
 * delay < 0  : invalidate cache (fast : entries will be deleted later)
 * delay >= 0 : invalidate & flush cache (can be long)
 */
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void rt_cache_flush(int delay)
{
778 779 780
	rt_cache_invalidate();
	if (delay >= 0)
		rt_do_flush(!in_softirq());
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}

783
/*
784
 * We change rt_genid and let gc do the cleanup
785
 */
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static void rt_secret_rebuild(unsigned long dummy)
{
788
	rt_cache_invalidate();
789
	mod_timer(&rt_secret_timer, jiffies + ip_rt_secret_interval);
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}

/*
   Short description of GC goals.

   We want to build algorithm, which will keep routing cache
   at some equilibrium point, when number of aged off entries
   is kept approximately equal to newly generated ones.

   Current expiration strength is variable "expire".
   We try to adjust it dynamically, so that if networking
   is idle expires is large enough to keep enough of warm entries,
   and when load increases it reduces to limit cache size.
 */

805
static int rt_garbage_collect(struct dst_ops *ops)
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{
	static unsigned long expire = RT_GC_TIMEOUT;
	static unsigned long last_gc;
	static int rover;
	static int equilibrium;
	struct rtable *rth, **rthp;
	unsigned long now = jiffies;
	int goal;

	/*
	 * Garbage collection is pretty expensive,
	 * do not make it too frequently.
	 */

	RT_CACHE_STAT_INC(gc_total);

	if (now - last_gc < ip_rt_gc_min_interval &&
	    atomic_read(&ipv4_dst_ops.entries) < ip_rt_max_size) {
		RT_CACHE_STAT_INC(gc_ignored);
		goto out;
	}

	/* Calculate number of entries, which we want to expire now. */
	goal = atomic_read(&ipv4_dst_ops.entries) -
		(ip_rt_gc_elasticity << rt_hash_log);
	if (goal <= 0) {
		if (equilibrium < ipv4_dst_ops.gc_thresh)
			equilibrium = ipv4_dst_ops.gc_thresh;
		goal = atomic_read(&ipv4_dst_ops.entries) - equilibrium;
		if (goal > 0) {
836
			equilibrium += min_t(unsigned int, goal >> 1, rt_hash_mask + 1);
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			goal = atomic_read(&ipv4_dst_ops.entries) - equilibrium;
		}
	} else {
		/* We are in dangerous area. Try to reduce cache really
		 * aggressively.
		 */
843
		goal = max_t(unsigned int, goal >> 1, rt_hash_mask + 1);
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		equilibrium = atomic_read(&ipv4_dst_ops.entries) - goal;
	}

	if (now - last_gc >= ip_rt_gc_min_interval)
		last_gc = now;

	if (goal <= 0) {
		equilibrium += goal;
		goto work_done;
	}

	do {
		int i, k;

		for (i = rt_hash_mask, k = rover; i >= 0; i--) {
			unsigned long tmo = expire;

			k = (k + 1) & rt_hash_mask;
			rthp = &rt_hash_table[k].chain;
863
			spin_lock_bh(rt_hash_lock_addr(k));
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			while ((rth = *rthp) != NULL) {
865 866
				if (rth->rt_genid == atomic_read(&rt_genid) &&
					!rt_may_expire(rth, tmo, expire)) {
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					tmo >>= 1;
868
					rthp = &rth->u.dst.rt_next;
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					continue;
				}
871
				*rthp = rth->u.dst.rt_next;
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				rt_free(rth);
				goal--;
			}
875
			spin_unlock_bh(rt_hash_lock_addr(k));
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			if (goal <= 0)
				break;
		}
		rover = k;

		if (goal <= 0)
			goto work_done;

		/* Goal is not achieved. We stop process if:

		   - if expire reduced to zero. Otherwise, expire is halfed.
		   - if table is not full.
		   - if we are called from interrupt.
		   - jiffies check is just fallback/debug loop breaker.
		     We will not spin here for long time in any case.
		 */

		RT_CACHE_STAT_INC(gc_goal_miss);

		if (expire == 0)
			break;

		expire >>= 1;
#if RT_CACHE_DEBUG >= 2
		printk(KERN_DEBUG "expire>> %u %d %d %d\n", expire,
				atomic_read(&ipv4_dst_ops.entries), goal, i);
#endif

		if (atomic_read(&ipv4_dst_ops.entries) < ip_rt_max_size)
			goto out;
	} while (!in_softirq() && time_before_eq(jiffies, now));

	if (atomic_read(&ipv4_dst_ops.entries) < ip_rt_max_size)
		goto out;
	if (net_ratelimit())
		printk(KERN_WARNING "dst cache overflow\n");
	RT_CACHE_STAT_INC(gc_dst_overflow);
	return 1;

work_done:
	expire += ip_rt_gc_min_interval;
	if (expire > ip_rt_gc_timeout ||
	    atomic_read(&ipv4_dst_ops.entries) < ipv4_dst_ops.gc_thresh)
		expire = ip_rt_gc_timeout;
#if RT_CACHE_DEBUG >= 2
	printk(KERN_DEBUG "expire++ %u %d %d %d\n", expire,
			atomic_read(&ipv4_dst_ops.entries), goal, rover);
#endif
out:	return 0;
}

static int rt_intern_hash(unsigned hash, struct rtable *rt, struct rtable **rp)
{
	struct rtable	*rth, **rthp;
	unsigned long	now;
	struct rtable *cand, **candp;
	u32 		min_score;
	int		chain_length;
	int attempts = !in_softirq();

restart:
	chain_length = 0;
	min_score = ~(u32)0;
	cand = NULL;
	candp = NULL;
	now = jiffies;

	rthp = &rt_hash_table[hash].chain;

945
	spin_lock_bh(rt_hash_lock_addr(hash));
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	while ((rth = *rthp) != NULL) {
947 948 949 950 951
		if (rth->rt_genid != atomic_read(&rt_genid)) {
			*rthp = rth->u.dst.rt_next;
			rt_free(rth);
			continue;
		}
952
		if (compare_keys(&rth->fl, &rt->fl) && compare_netns(rth, rt)) {
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			/* Put it first */
954
			*rthp = rth->u.dst.rt_next;
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			/*
			 * Since lookup is lockfree, the deletion
			 * must be visible to another weakly ordered CPU before
			 * the insertion at the start of the hash chain.
			 */
960
			rcu_assign_pointer(rth->u.dst.rt_next,
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					   rt_hash_table[hash].chain);
			/*
			 * Since lookup is lockfree, the update writes
			 * must be ordered for consistency on SMP.
			 */
			rcu_assign_pointer(rt_hash_table[hash].chain, rth);

968
			dst_use(&rth->u.dst, now);
969
			spin_unlock_bh(rt_hash_lock_addr(hash));
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			rt_drop(rt);
			*rp = rth;
			return 0;
		}

		if (!atomic_read(&rth->u.dst.__refcnt)) {
			u32 score = rt_score(rth);

			if (score <= min_score) {
				cand = rth;
				candp = rthp;
				min_score = score;
			}
		}

		chain_length++;

988
		rthp = &rth->u.dst.rt_next;
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	}

	if (cand) {
		/* ip_rt_gc_elasticity used to be average length of chain
		 * length, when exceeded gc becomes really aggressive.
		 *
		 * The second limit is less certain. At the moment it allows
		 * only 2 entries per bucket. We will see.
		 */
		if (chain_length > ip_rt_gc_elasticity) {
999
			*candp = cand->u.dst.rt_next;
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			rt_free(cand);
		}
	}

	/* Try to bind route to arp only if it is output
	   route or unicast forwarding path.
	 */
	if (rt->rt_type == RTN_UNICAST || rt->fl.iif == 0) {
		int err = arp_bind_neighbour(&rt->u.dst);
		if (err) {
1010
			spin_unlock_bh(rt_hash_lock_addr(hash));
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			if (err != -ENOBUFS) {
				rt_drop(rt);
				return err;
			}

			/* Neighbour tables are full and nothing
			   can be released. Try to shrink route cache,
			   it is most likely it holds some neighbour records.
			 */
			if (attempts-- > 0) {
				int saved_elasticity = ip_rt_gc_elasticity;
				int saved_int = ip_rt_gc_min_interval;
				ip_rt_gc_elasticity	= 1;
				ip_rt_gc_min_interval	= 0;
1026
				rt_garbage_collect(&ipv4_dst_ops);
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				ip_rt_gc_min_interval	= saved_int;
				ip_rt_gc_elasticity	= saved_elasticity;
				goto restart;
			}

			if (net_ratelimit())
				printk(KERN_WARNING "Neighbour table overflow.\n");
			rt_drop(rt);
			return -ENOBUFS;
		}
	}

1039
	rt->u.dst.rt_next = rt_hash_table[hash].chain;
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#if RT_CACHE_DEBUG >= 2
1041
	if (rt->u.dst.rt_next) {
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		struct rtable *trt;
		printk(KERN_DEBUG "rt_cache @%02x: %u.%u.%u.%u", hash,
		       NIPQUAD(rt->rt_dst));
1045
		for (trt = rt->u.dst.rt_next; trt; trt = trt->u.dst.rt_next)
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			printk(" . %u.%u.%u.%u", NIPQUAD(trt->rt_dst));
		printk("\n");
	}
#endif
	rt_hash_table[hash].chain = rt;
1051
	spin_unlock_bh(rt_hash_lock_addr(hash));
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	*rp = rt;
	return 0;
}

void rt_bind_peer(struct rtable *rt, int create)
{
	static DEFINE_SPINLOCK(rt_peer_lock);
	struct inet_peer *peer;

	peer = inet_getpeer(rt->rt_dst, create);

	spin_lock_bh(&rt_peer_lock);
	if (rt->peer == NULL) {
		rt->peer = peer;
		peer = NULL;
	}
	spin_unlock_bh(&rt_peer_lock);
	if (peer)
		inet_putpeer(peer);
}

/*
 * Peer allocation may fail only in serious out-of-memory conditions.  However
 * we still can generate some output.
 * Random ID selection looks a bit dangerous because we have no chances to
 * select ID being unique in a reasonable period of time.
 * But broken packet identifier may be better than no packet at all.
 */
static void ip_select_fb_ident(struct iphdr *iph)
{
	static DEFINE_SPINLOCK(ip_fb_id_lock);
	static u32 ip_fallback_id;
	u32 salt;

	spin_lock_bh(&ip_fb_id_lock);
1087
	salt = secure_ip_id((__force __be32)ip_fallback_id ^ iph->daddr);
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	iph->id = htons(salt & 0xFFFF);
	ip_fallback_id = salt;
	spin_unlock_bh(&ip_fb_id_lock);
}

void __ip_select_ident(struct iphdr *iph, struct dst_entry *dst, int more)
{
	struct rtable *rt = (struct rtable *) dst;

	if (rt) {
		if (rt->peer == NULL)
			rt_bind_peer(rt, 1);

		/* If peer is attached to destination, it is never detached,
		   so that we need not to grab a lock to dereference it.
		 */
		if (rt->peer) {
			iph->id = htons(inet_getid(rt->peer, more));
			return;
		}
	} else
1109
		printk(KERN_DEBUG "rt_bind_peer(0) @%p\n",
1110
		       __builtin_return_address(0));
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	ip_select_fb_ident(iph);
}

static void rt_del(unsigned hash, struct rtable *rt)
{
1117
	struct rtable **rthp, *aux;
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1119
	rthp = &rt_hash_table[hash].chain;
1120
	spin_lock_bh(rt_hash_lock_addr(hash));
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	ip_rt_put(rt);
1122 1123 1124 1125 1126
	while ((aux = *rthp) != NULL) {
		if (aux == rt || (aux->rt_genid != atomic_read(&rt_genid))) {
			*rthp = aux->u.dst.rt_next;
			rt_free(aux);
			continue;
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		}
1128 1129
		rthp = &aux->u.dst.rt_next;
	}
1130
	spin_unlock_bh(rt_hash_lock_addr(hash));
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}

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void ip_rt_redirect(__be32 old_gw, __be32 daddr, __be32 new_gw,
		    __be32 saddr, struct net_device *dev)
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{
	int i, k;
	struct in_device *in_dev = in_dev_get(dev);
	struct rtable *rth, **rthp;
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	__be32  skeys[2] = { saddr, 0 };
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	int  ikeys[2] = { dev->ifindex, 0 };
1141
	struct netevent_redirect netevent;
1142
	struct net *net;
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	if (!in_dev)
		return;

1147
	net = dev->nd_net;
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	if (new_gw == old_gw || !IN_DEV_RX_REDIRECTS(in_dev)
1149
	    || ipv4_is_multicast(new_gw) || ipv4_is_lbcast(new_gw)
1150
	    || ipv4_is_zeronet(new_gw))
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		goto reject_redirect;

	if (!IN_DEV_SHARED_MEDIA(in_dev)) {
		if (!inet_addr_onlink(in_dev, new_gw, old_gw))
			goto reject_redirect;
		if (IN_DEV_SEC_REDIRECTS(in_dev) && ip_fib_check_default(new_gw, dev))
			goto reject_redirect;
	} else {
1159
		if (inet_addr_type(net, new_gw) != RTN_UNICAST)
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			goto reject_redirect;
	}

	for (i = 0; i < 2; i++) {
		for (k = 0; k < 2; k++) {
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			unsigned hash = rt_hash(daddr, skeys[i], ikeys[k]);
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			rthp=&rt_hash_table[hash].chain;

			rcu_read_lock();
			while ((rth = rcu_dereference(*rthp)) != NULL) {
				struct rtable *rt;

				if (rth->fl.fl4_dst != daddr ||
				    rth->fl.fl4_src != skeys[i] ||
				    rth->fl.oif != ikeys[k] ||
1176
				    rth->fl.iif != 0 ||
1177 1178
				    rth->rt_genid != atomic_read(&rt_genid) ||
				    rth->u.dst.dev->nd_net != net) {
1179
					rthp = &rth->u.dst.rt_next;
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					continue;
				}

				if (rth->rt_dst != daddr ||
				    rth->rt_src != saddr ||
				    rth->u.dst.error ||
				    rth->rt_gateway != old_gw ||
				    rth->u.dst.dev != dev)
					break;

				dst_hold(&rth->u.dst);
				rcu_read_unlock();

				rt = dst_alloc(&ipv4_dst_ops);
				if (rt == NULL) {
					ip_rt_put(rth);
					in_dev_put(in_dev);
					return;
				}

				/* Copy all the information. */
				*rt = *rth;
1202
				INIT_RCU_HEAD(&rt->u.dst.rcu_head);
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				rt->u.dst.__use		= 1;
				atomic_set(&rt->u.dst.__refcnt, 1);
				rt->u.dst.child		= NULL;
				if (rt->u.dst.dev)
					dev_hold(rt->u.dst.dev);
				if (rt->idev)
					in_dev_hold(rt->idev);
				rt->u.dst.obsolete	= 0;
				rt->u.dst.lastuse	= jiffies;
				rt->u.dst.path		= &rt->u.dst;
				rt->u.dst.neighbour	= NULL;
				rt->u.dst.hh		= NULL;
				rt->u.dst.xfrm		= NULL;
1216
				rt->rt_genid		= atomic_read(&rt_genid);
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				rt->rt_flags		|= RTCF_REDIRECTED;

				/* Gateway is different ... */
				rt->rt_gateway		= new_gw;

				/* Redirect received -> path was valid */
				dst_confirm(&rth->u.dst);

				if (rt->peer)
					atomic_inc(&rt->peer->refcnt);

				if (arp_bind_neighbour(&rt->u.dst) ||
				    !(rt->u.dst.neighbour->nud_state &
					    NUD_VALID)) {
					if (rt->u.dst.neighbour)
						neigh_event_send(rt->u.dst.neighbour, NULL);
					ip_rt_put(rth);
					rt_drop(rt);
					goto do_next;
				}
1237

1238 1239
				netevent.old = &rth->u.dst;
				netevent.new = &rt->u.dst;
1240 1241
				call_netevent_notifiers(NETEVENT_REDIRECT,
							&netevent);
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				rt_del(hash, rth);
				if (!rt_intern_hash(hash, rt, &rt))
					ip_rt_put(rt);
				goto do_next;
			}
			rcu_read_unlock();
		do_next:
			;
		}
	}
	in_dev_put(in_dev);
	return;

reject_redirect:
#ifdef CONFIG_IP_ROUTE_VERBOSE
	if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit())
		printk(KERN_INFO "Redirect from %u.%u.%u.%u on %s about "
			"%u.%u.%u.%u ignored.\n"
1261
			"  Advised path = %u.%u.%u.%u -> %u.%u.%u.%u\n",
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		       NIPQUAD(old_gw), dev->name, NIPQUAD(new_gw),
1263
		       NIPQUAD(saddr), NIPQUAD(daddr));
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#endif
	in_dev_put(in_dev);
}

static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst)
{
	struct rtable *rt = (struct rtable*)dst;
	struct dst_entry *ret = dst;

	if (rt) {
		if (dst->obsolete) {
			ip_rt_put(rt);
			ret = NULL;
		} else if ((rt->rt_flags & RTCF_REDIRECTED) ||
			   rt->u.dst.expires) {
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			unsigned hash = rt_hash(rt->fl.fl4_dst, rt->fl.fl4_src,
						rt->fl.oif);
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#if RT_CACHE_DEBUG >= 1
1282
			printk(KERN_DEBUG "ipv4_negative_advice: redirect to "
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					  "%u.%u.%u.%u/%02x dropped\n",
				NIPQUAD(rt->rt_dst), rt->fl.fl4_tos);
#endif
			rt_del(hash, rt);
			ret = NULL;
		}
	}
	return ret;
}

/*
 * Algorithm:
 *	1. The first ip_rt_redirect_number redirects are sent
 *	   with exponential backoff, then we stop sending them at all,
 *	   assuming that the host ignores our redirects.
 *	2. If we did not see packets requiring redirects
 *	   during ip_rt_redirect_silence, we assume that the host
 *	   forgot redirected route and start to send redirects again.
 *
 * This algorithm is much cheaper and more intelligent than dumb load limiting
 * in icmp.c.
 *
 * NOTE. Do not forget to inhibit load limiting for redirects (redundant)
 * and "frag. need" (breaks PMTU discovery) in icmp.c.
 */

void ip_rt_send_redirect(struct sk_buff *skb)
{
	struct rtable *rt = (struct rtable*)skb->dst;
	struct in_device *in_dev = in_dev_get(rt->u.dst.dev);

	if (!in_dev)
		return;

	if (!IN_DEV_TX_REDIRECTS(in_dev))
		goto out;

	/* No redirected packets during ip_rt_redirect_silence;
	 * reset the algorithm.
	 */
	if (time_after(jiffies, rt->u.dst.rate_last + ip_rt_redirect_silence))
		rt->u.dst.rate_tokens = 0;

	/* Too many ignored redirects; do not send anything
	 * set u.dst.rate_last to the last seen redirected packet.
	 */
	if (rt->u.dst.rate_tokens >= ip_rt_redirect_number) {
		rt->u.dst.rate_last = jiffies;
		goto out;
	}

	/* Check for load limit; set rate_last to the latest sent
	 * redirect.
	 */
1337 1338
	if (rt->u.dst.rate_tokens == 0 ||
	    time_after(jiffies,
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		       (rt->u.dst.rate_last +
			(ip_rt_redirect_load << rt->u.dst.rate_tokens)))) {
		icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, rt->rt_gateway);
		rt->u.dst.rate_last = jiffies;
		++rt->u.dst.rate_tokens;
#ifdef CONFIG_IP_ROUTE_VERBOSE
		if (IN_DEV_LOG_MARTIANS(in_dev) &&
		    rt->u.dst.rate_tokens == ip_rt_redirect_number &&
		    net_ratelimit())
			printk(KERN_WARNING "host %u.%u.%u.%u/if%d ignores "
				"redirects for %u.%u.%u.%u to %u.%u.%u.%u.\n",
				NIPQUAD(rt->rt_src), rt->rt_iif,
				NIPQUAD(rt->rt_dst), NIPQUAD(rt->rt_gateway));
#endif
	}
out:
1355
	in_dev_put(in_dev);
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}

static int ip_error(struct sk_buff *skb)
{
	struct rtable *rt = (struct rtable*)skb->dst;
	unsigned long now;
	int code;

	switch (rt->u.dst.error) {
		case EINVAL:
		default:
			goto out;
		case EHOSTUNREACH:
			code = ICMP_HOST_UNREACH;
			break;
		case ENETUNREACH:
			code = ICMP_NET_UNREACH;
1373
			IP_INC_STATS_BH(IPSTATS_MIB_INNOROUTES);
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			break;
		case EACCES:
			code = ICMP_PKT_FILTERED;
			break;
	}

	now = jiffies;
	rt->u.dst.rate_tokens += now - rt->u.dst.rate_last;
	if (rt->u.dst.rate_tokens > ip_rt_error_burst)
		rt->u.dst.rate_tokens = ip_rt_error_burst;
	rt->u.dst.rate_last = now;
	if (rt->u.dst.rate_tokens >= ip_rt_error_cost) {
		rt->u.dst.rate_tokens -= ip_rt_error_cost;
		icmp_send(skb, ICMP_DEST_UNREACH, code, 0);
	}

out:	kfree_skb(skb);
	return 0;
1392
}
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/*
 *	The last two values are not from the RFC but
 *	are needed for AMPRnet AX.25 paths.
 */

1399
static const unsigned short mtu_plateau[] =
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{32000, 17914, 8166, 4352, 2002, 1492, 576, 296, 216, 128 };

static __inline__ unsigned short guess_mtu(unsigned short old_mtu)
{
	int i;
1405

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	for (i = 0; i < ARRAY_SIZE(mtu_plateau); i++)
		if (old_mtu > mtu_plateau[i])
			return mtu_plateau[i];
	return 68;
}

1412 1413
unsigned short ip_rt_frag_needed(struct net *net, struct iphdr *iph,
				 unsigned short new_mtu)
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{
	int i;
	unsigned short old_mtu = ntohs(iph->tot_len);
	struct rtable *rth;
1418 1419
	__be32  skeys[2] = { iph->saddr, 0, };
	__be32  daddr = iph->daddr;
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	unsigned short est_mtu = 0;

	if (ipv4_config.no_pmtu_disc)
		return 0;

	for (i = 0; i < 2; i++) {
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		unsigned hash = rt_hash(daddr, skeys[i], 0);
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		rcu_read_lock();
		for (rth = rcu_dereference(rt_hash_table[hash].chain); rth;
1430
		     rth = rcu_dereference(rth->u.dst.rt_next)) {
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			if (rth->fl.fl4_dst == daddr &&
			    rth->fl.fl4_src == skeys[i] &&
			    rth->rt_dst  == daddr &&
			    rth->rt_src  == iph->saddr &&
			    rth->fl.iif == 0 &&
1436
			    !(dst_metric_locked(&rth->u.dst, RTAX_MTU)) &&
1437 1438
			    rth->u.dst.dev->nd_net == net &&
			    rth->rt_genid == atomic_read(&rt_genid)) {
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				unsigned short mtu = new_mtu;

				if (new_mtu < 68 || new_mtu >= old_mtu) {

					/* BSD 4.2 compatibility hack :-( */
					if (mtu == 0 &&
					    old_mtu >= rth->u.dst.metrics[RTAX_MTU-1] &&
					    old_mtu >= 68 + (iph->ihl << 2))
						old_mtu -= iph->ihl << 2;

					mtu = guess_mtu(old_mtu);
				}
				if (mtu <= rth->u.dst.metrics[RTAX_MTU-1]) {
1452
					if (mtu < rth->u.dst.metrics[RTAX_MTU-1]) {
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						dst_confirm(&rth->u.dst);
						if (mtu < ip_rt_min_pmtu) {
							mtu = ip_rt_min_pmtu;
							rth->u.dst.metrics[RTAX_LOCK-1] |=
								(1 << RTAX_MTU);
						}
						rth->u.dst.metrics[RTAX_MTU-1] = mtu;
						dst_set_expires(&rth->u.dst,
							ip_rt_mtu_expires);
					}
					est_mtu = mtu;
				}
			}
		}
		rcu_read_unlock();
	}
	return est_mtu ? : new_mtu;
}

static void ip_rt_update_pmtu(struct dst_entry *dst, u32 mtu)
{
	if (dst->metrics[RTAX_MTU-1] > mtu && mtu >= 68 &&
	    !(dst_metric_locked(dst, RTAX_MTU))) {
		if (mtu < ip_rt_min_pmtu) {
			mtu = ip_rt_min_pmtu;
			dst->metrics[RTAX_LOCK-1] |= (1 << RTAX_MTU);
		}
		dst->metrics[RTAX_MTU-1] = mtu;
		dst_set_expires(dst, ip_rt_mtu_expires);
1482
		call_netevent_notifiers(NETEVENT_PMTU_UPDATE, dst);
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	}
}

static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie)
{
	return NULL;
}

static void ipv4_dst_destroy(struct dst_entry *dst)
{
	struct rtable *rt = (struct rtable *) dst;
	struct inet_peer *peer = rt->peer;
	struct in_device *idev = rt->idev;

	if (peer) {
		rt->peer = NULL;
		inet_putpeer(peer);
	}

	if (idev) {
		rt->idev = NULL;
		in_dev_put(idev);
	}
}

static void ipv4_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
			    int how)
{
	struct rtable *rt = (struct rtable *) dst;
	struct in_device *idev = rt->idev;
1513 1514 1515
	if (dev != dev->nd_net->loopback_dev && idev && idev->dev == dev) {
		struct in_device *loopback_idev =
			in_dev_get(dev->nd_net->loopback_dev);
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		if (loopback_idev) {
			rt->idev = loopback_idev;
			in_dev_put(idev);
		}
	}
}

static void ipv4_link_failure(struct sk_buff *skb)
{
	struct rtable *rt;

	icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0);

	rt = (struct rtable *) skb->dst;
	if (rt)
		dst_set_expires(&rt->u.dst, 0);
}

static int ip_rt_bug(struct sk_buff *skb)
{
	printk(KERN_DEBUG "ip_rt_bug: %u.%u.%u.%u -> %u.%u.%u.%u, %s\n",
1537
		NIPQUAD(ip_hdr(skb)->saddr), NIPQUAD(ip_hdr(skb)->daddr),
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		skb->dev ? skb->dev->name : "?");
	kfree_skb(skb);
	return 0;
}

/*
   We do not cache source address of outgoing interface,
   because it is used only by IP RR, TS and SRR options,
   so that it out of fast path.

   BTW remember: "addr" is allowed to be not aligned
   in IP options!
 */

void ip_rt_get_source(u8 *addr, struct rtable *rt)
{
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	__be32 src;
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	struct fib_result res;

	if (rt->fl.iif == 0)
		src = rt->rt_src;
1559
	else if (fib_lookup(rt->u.dst.dev->nd_net, &rt->fl, &res) == 0) {
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		src = FIB_RES_PREFSRC(res);
		fib_res_put(&res);
	} else
		src = inet_select_addr(rt->u.dst.dev, rt->rt_gateway,
					RT_SCOPE_UNIVERSE);
	memcpy(addr, &src, 4);
}

#ifdef CONFIG_NET_CLS_ROUTE
static void set_class_tag(struct rtable *rt, u32 tag)
{
	if (!(rt->u.dst.tclassid & 0xFFFF))
		rt->u.dst.tclassid |= tag & 0xFFFF;
	if (!(rt->u.dst.tclassid & 0xFFFF0000))
		rt->u.dst.tclassid |= tag & 0xFFFF0000;
}
#endif

static void rt_set_nexthop(struct rtable *rt, struct fib_result *res, u32 itag)
{
	struct fib_info *fi = res->fi;

	if (fi) {
		if (FIB_RES_GW(*res) &&
		    FIB_RES_NH(*res).nh_scope == RT_SCOPE_LINK)
			rt->rt_gateway = FIB_RES_GW(*res);
		memcpy(rt->u.dst.metrics, fi->fib_metrics,
		       sizeof(rt->u.dst.metrics));
		if (fi->fib_mtu == 0) {
			rt->u.dst.metrics[RTAX_MTU-1] = rt->u.dst.dev->mtu;
			if (rt->u.dst.metrics[RTAX_LOCK-1] & (1 << RTAX_MTU) &&
			    rt->rt_gateway != rt->rt_dst &&
			    rt->u.dst.dev->mtu > 576)
				rt->u.dst.metrics[RTAX_MTU-1] = 576;
		}
#ifdef CONFIG_NET_CLS_ROUTE
		rt->u.dst.tclassid = FIB_RES_NH(*res).nh_tclassid;
#endif
	} else
		rt->u.dst.metrics[RTAX_MTU-1]= rt->u.dst.dev->mtu;

	if (rt->u.dst.metrics[RTAX_HOPLIMIT-1] == 0)
		rt->u.dst.metrics[RTAX_HOPLIMIT-1] = sysctl_ip_default_ttl;
	if (rt->u.dst.metrics[RTAX_MTU-1] > IP_MAX_MTU)
		rt->u.dst.metrics[RTAX_MTU-1] = IP_MAX_MTU;
	if (rt->u.dst.metrics[RTAX_ADVMSS-1] == 0)
		rt->u.dst.metrics[RTAX_ADVMSS-1] = max_t(unsigned int, rt->u.dst.dev->mtu - 40,
				       ip_rt_min_advmss);
	if (rt->u.dst.metrics[RTAX_ADVMSS-1] > 65535 - 40)
		rt->u.dst.metrics[RTAX_ADVMSS-1] = 65535 - 40;

#ifdef CONFIG_NET_CLS_ROUTE
#ifdef CONFIG_IP_MULTIPLE_TABLES
	set_class_tag(rt, fib_rules_tclass(res));
#endif
	set_class_tag(rt, itag);
#endif
1617
	rt->rt_type = res->type;
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}

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static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
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				u8 tos, struct net_device *dev, int our)
{
	unsigned hash;
	struct rtable *rth;
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	__be32 spec_dst;
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	struct in_device *in_dev = in_dev_get(dev);
	u32 itag = 0;

	/* Primary sanity checks. */

	if (in_dev == NULL)
		return -EINVAL;

1634
	if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) ||
1635
	    ipv4_is_loopback(saddr) || skb->protocol != htons(ETH_P_IP))
L
Linus Torvalds 已提交
1636 1637
		goto e_inval;

1638 1639
	if (ipv4_is_zeronet(saddr)) {
		if (!ipv4_is_local_multicast(daddr))
L
Linus Torvalds 已提交
1640 1641 1642 1643 1644 1645 1646 1647 1648 1649 1650 1651 1652 1653
			goto e_inval;
		spec_dst = inet_select_addr(dev, 0, RT_SCOPE_LINK);
	} else if (fib_validate_source(saddr, 0, tos, 0,
					dev, &spec_dst, &itag) < 0)
		goto e_inval;

	rth = dst_alloc(&ipv4_dst_ops);
	if (!rth)
		goto e_nobufs;

	rth->u.dst.output= ip_rt_bug;

	atomic_set(&rth->u.dst.__refcnt, 1);
	rth->u.dst.flags= DST_HOST;
1654
	if (IN_DEV_CONF_GET(in_dev, NOPOLICY))
L
Linus Torvalds 已提交
1655 1656 1657 1658
		rth->u.dst.flags |= DST_NOPOLICY;
	rth->fl.fl4_dst	= daddr;
	rth->rt_dst	= daddr;
	rth->fl.fl4_tos	= tos;
1659
	rth->fl.mark    = skb->mark;
L
Linus Torvalds 已提交
1660 1661 1662 1663 1664 1665 1666
	rth->fl.fl4_src	= saddr;
	rth->rt_src	= saddr;
#ifdef CONFIG_NET_CLS_ROUTE
	rth->u.dst.tclassid = itag;
#endif
	rth->rt_iif	=
	rth->fl.iif	= dev->ifindex;
1667
	rth->u.dst.dev	= init_net.loopback_dev;
L
Linus Torvalds 已提交
1668 1669 1670 1671 1672
	dev_hold(rth->u.dst.dev);
	rth->idev	= in_dev_get(rth->u.dst.dev);
	rth->fl.oif	= 0;
	rth->rt_gateway	= daddr;
	rth->rt_spec_dst= spec_dst;
1673
	rth->rt_genid	= atomic_read(&rt_genid);
L
Linus Torvalds 已提交
1674
	rth->rt_flags	= RTCF_MULTICAST;
1675
	rth->rt_type	= RTN_MULTICAST;
L
Linus Torvalds 已提交
1676 1677 1678 1679 1680 1681
	if (our) {
		rth->u.dst.input= ip_local_deliver;
		rth->rt_flags |= RTCF_LOCAL;
	}

#ifdef CONFIG_IP_MROUTE
1682
	if (!ipv4_is_local_multicast(daddr) && IN_DEV_MFORWARD(in_dev))
L
Linus Torvalds 已提交
1683 1684 1685 1686 1687
		rth->u.dst.input = ip_mr_input;
#endif
	RT_CACHE_STAT_INC(in_slow_mc);

	in_dev_put(in_dev);
A
Al Viro 已提交
1688
	hash = rt_hash(daddr, saddr, dev->ifindex);
L
Linus Torvalds 已提交
1689 1690 1691 1692 1693 1694 1695 1696 1697 1698 1699 1700 1701 1702 1703
	return rt_intern_hash(hash, rth, (struct rtable**) &skb->dst);

e_nobufs:
	in_dev_put(in_dev);
	return -ENOBUFS;

e_inval:
	in_dev_put(in_dev);
	return -EINVAL;
}


static void ip_handle_martian_source(struct net_device *dev,
				     struct in_device *in_dev,
				     struct sk_buff *skb,
A
Al Viro 已提交
1704 1705
				     __be32 daddr,
				     __be32 saddr)
L
Linus Torvalds 已提交
1706 1707 1708 1709 1710 1711 1712 1713 1714 1715 1716
{
	RT_CACHE_STAT_INC(in_martian_src);
#ifdef CONFIG_IP_ROUTE_VERBOSE
	if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) {
		/*
		 *	RFC1812 recommendation, if source is martian,
		 *	the only hint is MAC header.
		 */
		printk(KERN_WARNING "martian source %u.%u.%u.%u from "
			"%u.%u.%u.%u, on dev %s\n",
			NIPQUAD(daddr), NIPQUAD(saddr), dev->name);
1717
		if (dev->hard_header_len && skb_mac_header_was_set(skb)) {
L
Linus Torvalds 已提交
1718
			int i;
1719
			const unsigned char *p = skb_mac_header(skb);
L
Linus Torvalds 已提交
1720 1721 1722 1723 1724 1725 1726 1727 1728 1729 1730 1731
			printk(KERN_WARNING "ll header: ");
			for (i = 0; i < dev->hard_header_len; i++, p++) {
				printk("%02x", *p);
				if (i < (dev->hard_header_len - 1))
					printk(":");
			}
			printk("\n");
		}
	}
#endif
}

1732 1733 1734
static inline int __mkroute_input(struct sk_buff *skb,
				  struct fib_result* res,
				  struct in_device *in_dev,
A
Al Viro 已提交
1735
				  __be32 daddr, __be32 saddr, u32 tos,
1736
				  struct rtable **result)
L
Linus Torvalds 已提交
1737 1738 1739 1740 1741 1742
{

	struct rtable *rth;
	int err;
	struct in_device *out_dev;
	unsigned flags = 0;
1743 1744
	__be32 spec_dst;
	u32 itag;
L
Linus Torvalds 已提交
1745 1746 1747 1748 1749 1750 1751 1752 1753 1754 1755

	/* get a working reference to the output device */
	out_dev = in_dev_get(FIB_RES_DEV(*res));
	if (out_dev == NULL) {
		if (net_ratelimit())
			printk(KERN_CRIT "Bug in ip_route_input" \
			       "_slow(). Please, report\n");
		return -EINVAL;
	}


1756
	err = fib_validate_source(saddr, daddr, tos, FIB_RES_OIF(*res),
L
Linus Torvalds 已提交
1757 1758
				  in_dev->dev, &spec_dst, &itag);
	if (err < 0) {
1759
		ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr,
L
Linus Torvalds 已提交
1760
					 saddr);
1761

L
Linus Torvalds 已提交
1762 1763 1764 1765 1766 1767 1768
		err = -EINVAL;
		goto cleanup;
	}

	if (err)
		flags |= RTCF_DIRECTSRC;

1769
	if (out_dev == in_dev && err && !(flags & RTCF_MASQ) &&
L
Linus Torvalds 已提交
1770 1771 1772 1773 1774 1775 1776 1777
	    (IN_DEV_SHARED_MEDIA(out_dev) ||
	     inet_addr_onlink(out_dev, saddr, FIB_RES_GW(*res))))
		flags |= RTCF_DOREDIRECT;

	if (skb->protocol != htons(ETH_P_IP)) {
		/* Not IP (i.e. ARP). Do not create route, if it is
		 * invalid for proxy arp. DNAT routes are always valid.
		 */
1778
		if (out_dev == in_dev) {
L
Linus Torvalds 已提交
1779 1780 1781 1782 1783 1784 1785 1786 1787 1788 1789 1790
			err = -EINVAL;
			goto cleanup;
		}
	}


	rth = dst_alloc(&ipv4_dst_ops);
	if (!rth) {
		err = -ENOBUFS;
		goto cleanup;
	}

1791
	atomic_set(&rth->u.dst.__refcnt, 1);
L
Linus Torvalds 已提交
1792
	rth->u.dst.flags= DST_HOST;
1793
	if (IN_DEV_CONF_GET(in_dev, NOPOLICY))
L
Linus Torvalds 已提交
1794
		rth->u.dst.flags |= DST_NOPOLICY;
1795
	if (IN_DEV_CONF_GET(out_dev, NOXFRM))
L
Linus Torvalds 已提交
1796 1797 1798 1799
		rth->u.dst.flags |= DST_NOXFRM;
	rth->fl.fl4_dst	= daddr;
	rth->rt_dst	= daddr;
	rth->fl.fl4_tos	= tos;
1800
	rth->fl.mark    = skb->mark;
L
Linus Torvalds 已提交
1801 1802 1803 1804 1805 1806 1807 1808 1809 1810 1811 1812 1813
	rth->fl.fl4_src	= saddr;
	rth->rt_src	= saddr;
	rth->rt_gateway	= daddr;
	rth->rt_iif 	=
		rth->fl.iif	= in_dev->dev->ifindex;
	rth->u.dst.dev	= (out_dev)->dev;
	dev_hold(rth->u.dst.dev);
	rth->idev	= in_dev_get(rth->u.dst.dev);
	rth->fl.oif 	= 0;
	rth->rt_spec_dst= spec_dst;

	rth->u.dst.input = ip_forward;
	rth->u.dst.output = ip_output;
1814
	rth->rt_genid = atomic_read(&rt_genid);
L
Linus Torvalds 已提交
1815 1816 1817 1818 1819 1820 1821 1822 1823 1824 1825

	rt_set_nexthop(rth, res, itag);

	rth->rt_flags = flags;

	*result = rth;
	err = 0;
 cleanup:
	/* release the working reference to the output device */
	in_dev_put(out_dev);
	return err;
1826
}
L
Linus Torvalds 已提交
1827

1828 1829 1830 1831 1832
static inline int ip_mkroute_input(struct sk_buff *skb,
				   struct fib_result* res,
				   const struct flowi *fl,
				   struct in_device *in_dev,
				   __be32 daddr, __be32 saddr, u32 tos)
L
Linus Torvalds 已提交
1833
{
C
Chuck Short 已提交
1834
	struct rtable* rth = NULL;
L
Linus Torvalds 已提交
1835 1836 1837 1838 1839 1840 1841 1842 1843 1844 1845 1846 1847 1848
	int err;
	unsigned hash;

#ifdef CONFIG_IP_ROUTE_MULTIPATH
	if (res->fi && res->fi->fib_nhs > 1 && fl->oif == 0)
		fib_select_multipath(fl, res);
#endif

	/* create a routing cache entry */
	err = __mkroute_input(skb, res, in_dev, daddr, saddr, tos, &rth);
	if (err)
		return err;

	/* put it into the cache */
A
Al Viro 已提交
1849
	hash = rt_hash(daddr, saddr, fl->iif);
1850
	return rt_intern_hash(hash, rth, (struct rtable**)&skb->dst);
L
Linus Torvalds 已提交
1851 1852 1853 1854 1855 1856 1857 1858 1859 1860 1861 1862
}

/*
 *	NOTE. We drop all the packets that has local source
 *	addresses, because every properly looped back packet
 *	must have correct destination already attached by output routine.
 *
 *	Such approach solves two big problems:
 *	1. Not simplex devices are handled properly.
 *	2. IP spoofing attempts are filtered with 100% of guarantee.
 */

A
Al Viro 已提交
1863
static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
L
Linus Torvalds 已提交
1864 1865 1866 1867 1868 1869 1870 1871 1872 1873
			       u8 tos, struct net_device *dev)
{
	struct fib_result res;
	struct in_device *in_dev = in_dev_get(dev);
	struct flowi fl = { .nl_u = { .ip4_u =
				      { .daddr = daddr,
					.saddr = saddr,
					.tos = tos,
					.scope = RT_SCOPE_UNIVERSE,
				      } },
1874
			    .mark = skb->mark,
L
Linus Torvalds 已提交
1875 1876 1877 1878 1879
			    .iif = dev->ifindex };
	unsigned	flags = 0;
	u32		itag = 0;
	struct rtable * rth;
	unsigned	hash;
A
Al Viro 已提交
1880
	__be32		spec_dst;
L
Linus Torvalds 已提交
1881 1882
	int		err = -EINVAL;
	int		free_res = 0;
1883
	struct net    * net = dev->nd_net;
L
Linus Torvalds 已提交
1884 1885 1886 1887 1888 1889 1890 1891 1892 1893

	/* IP on this device is disabled. */

	if (!in_dev)
		goto out;

	/* Check for the most weird martians, which can be not detected
	   by fib_lookup.
	 */

1894
	if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) ||
1895
	    ipv4_is_loopback(saddr))
L
Linus Torvalds 已提交
1896 1897
		goto martian_source;

1898
	if (daddr == htonl(0xFFFFFFFF) || (saddr == 0 && daddr == 0))
L
Linus Torvalds 已提交
1899 1900 1901 1902 1903
		goto brd_input;

	/* Accept zero addresses only to limited broadcast;
	 * I even do not know to fix it or not. Waiting for complains :-)
	 */
1904
	if (ipv4_is_zeronet(saddr))
L
Linus Torvalds 已提交
1905 1906
		goto martian_source;

1907
	if (ipv4_is_lbcast(daddr) || ipv4_is_zeronet(daddr) ||
1908
	    ipv4_is_loopback(daddr))
L
Linus Torvalds 已提交
1909 1910 1911 1912 1913
		goto martian_destination;

	/*
	 *	Now we are ready to route packet.
	 */
1914
	if ((err = fib_lookup(net, &fl, &res)) != 0) {
L
Linus Torvalds 已提交
1915
		if (!IN_DEV_FORWARD(in_dev))
1916
			goto e_hostunreach;
L
Linus Torvalds 已提交
1917 1918 1919 1920 1921 1922 1923 1924 1925 1926 1927 1928
		goto no_route;
	}
	free_res = 1;

	RT_CACHE_STAT_INC(in_slow_tot);

	if (res.type == RTN_BROADCAST)
		goto brd_input;

	if (res.type == RTN_LOCAL) {
		int result;
		result = fib_validate_source(saddr, daddr, tos,
1929
					     net->loopback_dev->ifindex,
L
Linus Torvalds 已提交
1930 1931 1932 1933 1934 1935 1936 1937 1938 1939
					     dev, &spec_dst, &itag);
		if (result < 0)
			goto martian_source;
		if (result)
			flags |= RTCF_DIRECTSRC;
		spec_dst = daddr;
		goto local_input;
	}

	if (!IN_DEV_FORWARD(in_dev))
1940
		goto e_hostunreach;
L
Linus Torvalds 已提交
1941 1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 1954
	if (res.type != RTN_UNICAST)
		goto martian_destination;

	err = ip_mkroute_input(skb, &res, &fl, in_dev, daddr, saddr, tos);
done:
	in_dev_put(in_dev);
	if (free_res)
		fib_res_put(&res);
out:	return err;

brd_input:
	if (skb->protocol != htons(ETH_P_IP))
		goto e_inval;

1955
	if (ipv4_is_zeronet(saddr))
L
Linus Torvalds 已提交
1956 1957 1958 1959 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974
		spec_dst = inet_select_addr(dev, 0, RT_SCOPE_LINK);
	else {
		err = fib_validate_source(saddr, 0, tos, 0, dev, &spec_dst,
					  &itag);
		if (err < 0)
			goto martian_source;
		if (err)
			flags |= RTCF_DIRECTSRC;
	}
	flags |= RTCF_BROADCAST;
	res.type = RTN_BROADCAST;
	RT_CACHE_STAT_INC(in_brd);

local_input:
	rth = dst_alloc(&ipv4_dst_ops);
	if (!rth)
		goto e_nobufs;

	rth->u.dst.output= ip_rt_bug;
1975
	rth->rt_genid = atomic_read(&rt_genid);
L
Linus Torvalds 已提交
1976 1977 1978

	atomic_set(&rth->u.dst.__refcnt, 1);
	rth->u.dst.flags= DST_HOST;
1979
	if (IN_DEV_CONF_GET(in_dev, NOPOLICY))
L
Linus Torvalds 已提交
1980 1981 1982 1983
		rth->u.dst.flags |= DST_NOPOLICY;
	rth->fl.fl4_dst	= daddr;
	rth->rt_dst	= daddr;
	rth->fl.fl4_tos	= tos;
1984
	rth->fl.mark    = skb->mark;
L
Linus Torvalds 已提交
1985 1986 1987 1988 1989 1990 1991
	rth->fl.fl4_src	= saddr;
	rth->rt_src	= saddr;
#ifdef CONFIG_NET_CLS_ROUTE
	rth->u.dst.tclassid = itag;
#endif
	rth->rt_iif	=
	rth->fl.iif	= dev->ifindex;
1992
	rth->u.dst.dev	= net->loopback_dev;
L
Linus Torvalds 已提交
1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004
	dev_hold(rth->u.dst.dev);
	rth->idev	= in_dev_get(rth->u.dst.dev);
	rth->rt_gateway	= daddr;
	rth->rt_spec_dst= spec_dst;
	rth->u.dst.input= ip_local_deliver;
	rth->rt_flags 	= flags|RTCF_LOCAL;
	if (res.type == RTN_UNREACHABLE) {
		rth->u.dst.input= ip_error;
		rth->u.dst.error= -err;
		rth->rt_flags 	&= ~RTCF_LOCAL;
	}
	rth->rt_type	= res.type;
A
Al Viro 已提交
2005
	hash = rt_hash(daddr, saddr, fl.iif);
L
Linus Torvalds 已提交
2006 2007 2008 2009 2010 2011 2012
	err = rt_intern_hash(hash, rth, (struct rtable**)&skb->dst);
	goto done;

no_route:
	RT_CACHE_STAT_INC(in_no_route);
	spec_dst = inet_select_addr(dev, 0, RT_SCOPE_UNIVERSE);
	res.type = RTN_UNREACHABLE;
2013 2014
	if (err == -ESRCH)
		err = -ENETUNREACH;
L
Linus Torvalds 已提交
2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027
	goto local_input;

	/*
	 *	Do not cache martian addresses: they should be logged (RFC1812)
	 */
martian_destination:
	RT_CACHE_STAT_INC(in_martian_dst);
#ifdef CONFIG_IP_ROUTE_VERBOSE
	if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit())
		printk(KERN_WARNING "martian destination %u.%u.%u.%u from "
			"%u.%u.%u.%u, dev %s\n",
			NIPQUAD(daddr), NIPQUAD(saddr), dev->name);
#endif
2028 2029

e_hostunreach:
2030 2031
	err = -EHOSTUNREACH;
	goto done;
2032

L
Linus Torvalds 已提交
2033 2034 2035 2036 2037 2038 2039 2040 2041 2042 2043 2044 2045
e_inval:
	err = -EINVAL;
	goto done;

e_nobufs:
	err = -ENOBUFS;
	goto done;

martian_source:
	ip_handle_martian_source(dev, in_dev, skb, daddr, saddr);
	goto e_inval;
}

A
Al Viro 已提交
2046
int ip_route_input(struct sk_buff *skb, __be32 daddr, __be32 saddr,
L
Linus Torvalds 已提交
2047 2048 2049 2050 2051
		   u8 tos, struct net_device *dev)
{
	struct rtable * rth;
	unsigned	hash;
	int iif = dev->ifindex;
2052
	struct net *net;
L
Linus Torvalds 已提交
2053

2054
	net = dev->nd_net;
L
Linus Torvalds 已提交
2055
	tos &= IPTOS_RT_MASK;
A
Al Viro 已提交
2056
	hash = rt_hash(daddr, saddr, iif);
L
Linus Torvalds 已提交
2057 2058 2059

	rcu_read_lock();
	for (rth = rcu_dereference(rt_hash_table[hash].chain); rth;
2060
	     rth = rcu_dereference(rth->u.dst.rt_next)) {
L
Linus Torvalds 已提交
2061 2062 2063 2064
		if (rth->fl.fl4_dst == daddr &&
		    rth->fl.fl4_src == saddr &&
		    rth->fl.iif == iif &&
		    rth->fl.oif == 0 &&
2065
		    rth->fl.mark == skb->mark &&
2066
		    rth->fl.fl4_tos == tos &&
2067 2068
		    rth->u.dst.dev->nd_net == net &&
		    rth->rt_genid == atomic_read(&rt_genid)) {
2069
			dst_use(&rth->u.dst, jiffies);
L
Linus Torvalds 已提交
2070 2071 2072 2073 2074 2075 2076 2077 2078 2079 2080 2081 2082 2083 2084 2085 2086 2087 2088 2089
			RT_CACHE_STAT_INC(in_hit);
			rcu_read_unlock();
			skb->dst = (struct dst_entry*)rth;
			return 0;
		}
		RT_CACHE_STAT_INC(in_hlist_search);
	}
	rcu_read_unlock();

	/* Multicast recognition logic is moved from route cache to here.
	   The problem was that too many Ethernet cards have broken/missing
	   hardware multicast filters :-( As result the host on multicasting
	   network acquires a lot of useless route cache entries, sort of
	   SDR messages from all the world. Now we try to get rid of them.
	   Really, provided software IP multicast filter is organized
	   reasonably (at least, hashed), it does not result in a slowdown
	   comparing with route cache reject entries.
	   Note, that multicast routers are not affected, because
	   route cache entry is created eventually.
	 */
2090
	if (ipv4_is_multicast(daddr)) {
L
Linus Torvalds 已提交
2091 2092 2093
		struct in_device *in_dev;

		rcu_read_lock();
2094
		if ((in_dev = __in_dev_get_rcu(dev)) != NULL) {
L
Linus Torvalds 已提交
2095
			int our = ip_check_mc(in_dev, daddr, saddr,
2096
				ip_hdr(skb)->protocol);
L
Linus Torvalds 已提交
2097 2098
			if (our
#ifdef CONFIG_IP_MROUTE
2099 2100
			    || (!ipv4_is_local_multicast(daddr) &&
				IN_DEV_MFORWARD(in_dev))
L
Linus Torvalds 已提交
2101 2102 2103 2104 2105 2106 2107 2108 2109 2110 2111 2112 2113 2114
#endif
			    ) {
				rcu_read_unlock();
				return ip_route_input_mc(skb, daddr, saddr,
							 tos, dev, our);
			}
		}
		rcu_read_unlock();
		return -EINVAL;
	}
	return ip_route_input_slow(skb, daddr, saddr, tos, dev);
}

static inline int __mkroute_output(struct rtable **result,
2115
				   struct fib_result* res,
L
Linus Torvalds 已提交
2116
				   const struct flowi *fl,
2117 2118 2119
				   const struct flowi *oldflp,
				   struct net_device *dev_out,
				   unsigned flags)
L
Linus Torvalds 已提交
2120 2121 2122 2123 2124 2125
{
	struct rtable *rth;
	struct in_device *in_dev;
	u32 tos = RT_FL_TOS(oldflp);
	int err = 0;

2126
	if (ipv4_is_loopback(fl->fl4_src) && !(dev_out->flags&IFF_LOOPBACK))
L
Linus Torvalds 已提交
2127 2128
		return -EINVAL;

2129
	if (fl->fl4_dst == htonl(0xFFFFFFFF))
L
Linus Torvalds 已提交
2130
		res->type = RTN_BROADCAST;
2131
	else if (ipv4_is_multicast(fl->fl4_dst))
L
Linus Torvalds 已提交
2132
		res->type = RTN_MULTICAST;
2133
	else if (ipv4_is_lbcast(fl->fl4_dst) || ipv4_is_zeronet(fl->fl4_dst))
L
Linus Torvalds 已提交
2134 2135 2136 2137 2138 2139 2140 2141 2142 2143 2144 2145 2146 2147 2148 2149 2150 2151
		return -EINVAL;

	if (dev_out->flags & IFF_LOOPBACK)
		flags |= RTCF_LOCAL;

	/* get work reference to inet device */
	in_dev = in_dev_get(dev_out);
	if (!in_dev)
		return -EINVAL;

	if (res->type == RTN_BROADCAST) {
		flags |= RTCF_BROADCAST | RTCF_LOCAL;
		if (res->fi) {
			fib_info_put(res->fi);
			res->fi = NULL;
		}
	} else if (res->type == RTN_MULTICAST) {
		flags |= RTCF_MULTICAST|RTCF_LOCAL;
2152
		if (!ip_check_mc(in_dev, oldflp->fl4_dst, oldflp->fl4_src,
L
Linus Torvalds 已提交
2153 2154 2155 2156 2157 2158 2159 2160 2161 2162 2163 2164 2165 2166 2167 2168 2169
				 oldflp->proto))
			flags &= ~RTCF_LOCAL;
		/* If multicast route do not exist use
		   default one, but do not gateway in this case.
		   Yes, it is hack.
		 */
		if (res->fi && res->prefixlen < 4) {
			fib_info_put(res->fi);
			res->fi = NULL;
		}
	}


	rth = dst_alloc(&ipv4_dst_ops);
	if (!rth) {
		err = -ENOBUFS;
		goto cleanup;
2170
	}
L
Linus Torvalds 已提交
2171

2172
	atomic_set(&rth->u.dst.__refcnt, 1);
L
Linus Torvalds 已提交
2173
	rth->u.dst.flags= DST_HOST;
2174
	if (IN_DEV_CONF_GET(in_dev, NOXFRM))
L
Linus Torvalds 已提交
2175
		rth->u.dst.flags |= DST_NOXFRM;
2176
	if (IN_DEV_CONF_GET(in_dev, NOPOLICY))
L
Linus Torvalds 已提交
2177 2178 2179 2180 2181 2182
		rth->u.dst.flags |= DST_NOPOLICY;

	rth->fl.fl4_dst	= oldflp->fl4_dst;
	rth->fl.fl4_tos	= tos;
	rth->fl.fl4_src	= oldflp->fl4_src;
	rth->fl.oif	= oldflp->oif;
2183
	rth->fl.mark    = oldflp->mark;
L
Linus Torvalds 已提交
2184 2185 2186
	rth->rt_dst	= fl->fl4_dst;
	rth->rt_src	= fl->fl4_src;
	rth->rt_iif	= oldflp->oif ? : dev_out->ifindex;
2187
	/* get references to the devices that are to be hold by the routing
L
Linus Torvalds 已提交
2188 2189 2190 2191 2192 2193 2194 2195
	   cache entry */
	rth->u.dst.dev	= dev_out;
	dev_hold(dev_out);
	rth->idev	= in_dev_get(dev_out);
	rth->rt_gateway = fl->fl4_dst;
	rth->rt_spec_dst= fl->fl4_src;

	rth->u.dst.output=ip_output;
2196
	rth->rt_genid = atomic_read(&rt_genid);
L
Linus Torvalds 已提交
2197 2198 2199 2200 2201 2202 2203 2204 2205

	RT_CACHE_STAT_INC(out_slow_tot);

	if (flags & RTCF_LOCAL) {
		rth->u.dst.input = ip_local_deliver;
		rth->rt_spec_dst = fl->fl4_dst;
	}
	if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) {
		rth->rt_spec_dst = fl->fl4_src;
2206
		if (flags & RTCF_LOCAL &&
L
Linus Torvalds 已提交
2207 2208 2209 2210 2211 2212 2213
		    !(dev_out->flags & IFF_LOOPBACK)) {
			rth->u.dst.output = ip_mc_output;
			RT_CACHE_STAT_INC(out_slow_mc);
		}
#ifdef CONFIG_IP_MROUTE
		if (res->type == RTN_MULTICAST) {
			if (IN_DEV_MFORWARD(in_dev) &&
2214
			    !ipv4_is_local_multicast(oldflp->fl4_dst)) {
L
Linus Torvalds 已提交
2215 2216 2217 2218 2219 2220 2221 2222 2223 2224 2225 2226 2227 2228 2229 2230 2231 2232 2233
				rth->u.dst.input = ip_mr_input;
				rth->u.dst.output = ip_mc_output;
			}
		}
#endif
	}

	rt_set_nexthop(rth, res, 0);

	rth->rt_flags = flags;

	*result = rth;
 cleanup:
	/* release work reference to inet device */
	in_dev_put(in_dev);

	return err;
}

2234 2235 2236 2237 2238 2239
static inline int ip_mkroute_output(struct rtable **rp,
				    struct fib_result* res,
				    const struct flowi *fl,
				    const struct flowi *oldflp,
				    struct net_device *dev_out,
				    unsigned flags)
L
Linus Torvalds 已提交
2240
{
C
Chuck Short 已提交
2241
	struct rtable *rth = NULL;
L
Linus Torvalds 已提交
2242 2243 2244
	int err = __mkroute_output(&rth, res, fl, oldflp, dev_out, flags);
	unsigned hash;
	if (err == 0) {
A
Al Viro 已提交
2245
		hash = rt_hash(oldflp->fl4_dst, oldflp->fl4_src, oldflp->oif);
L
Linus Torvalds 已提交
2246 2247
		err = rt_intern_hash(hash, rth, rp);
	}
2248

L
Linus Torvalds 已提交
2249 2250 2251 2252 2253 2254 2255
	return err;
}

/*
 * Major route resolver routine.
 */

2256 2257
static int ip_route_output_slow(struct net *net, struct rtable **rp,
				const struct flowi *oldflp)
L
Linus Torvalds 已提交
2258 2259 2260 2261 2262 2263 2264 2265 2266 2267
{
	u32 tos	= RT_FL_TOS(oldflp);
	struct flowi fl = { .nl_u = { .ip4_u =
				      { .daddr = oldflp->fl4_dst,
					.saddr = oldflp->fl4_src,
					.tos = tos & IPTOS_RT_MASK,
					.scope = ((tos & RTO_ONLINK) ?
						  RT_SCOPE_LINK :
						  RT_SCOPE_UNIVERSE),
				      } },
2268
			    .mark = oldflp->mark,
2269
			    .iif = net->loopback_dev->ifindex,
L
Linus Torvalds 已提交
2270 2271 2272 2273 2274 2275 2276 2277 2278 2279 2280 2281 2282 2283 2284
			    .oif = oldflp->oif };
	struct fib_result res;
	unsigned flags = 0;
	struct net_device *dev_out = NULL;
	int free_res = 0;
	int err;


	res.fi		= NULL;
#ifdef CONFIG_IP_MULTIPLE_TABLES
	res.r		= NULL;
#endif

	if (oldflp->fl4_src) {
		err = -EINVAL;
2285
		if (ipv4_is_multicast(oldflp->fl4_src) ||
2286
		    ipv4_is_lbcast(oldflp->fl4_src) ||
2287
		    ipv4_is_zeronet(oldflp->fl4_src))
L
Linus Torvalds 已提交
2288 2289 2290
			goto out;

		/* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2291
		dev_out = ip_dev_find(net, oldflp->fl4_src);
2292
		if (dev_out == NULL)
L
Linus Torvalds 已提交
2293 2294 2295 2296
			goto out;

		/* I removed check for oif == dev_out->oif here.
		   It was wrong for two reasons:
2297 2298
		   1. ip_dev_find(net, saddr) can return wrong iface, if saddr
		      is assigned to multiple interfaces.
L
Linus Torvalds 已提交
2299 2300 2301 2302
		   2. Moreover, we are allowed to send packets with saddr
		      of another iface. --ANK
		 */

2303
		if (oldflp->oif == 0
2304 2305
		    && (ipv4_is_multicast(oldflp->fl4_dst) ||
			oldflp->fl4_dst == htonl(0xFFFFFFFF))) {
L
Linus Torvalds 已提交
2306 2307 2308 2309 2310 2311 2312 2313 2314 2315 2316 2317 2318 2319 2320 2321 2322 2323 2324 2325 2326 2327 2328 2329 2330
			/* Special hack: user can direct multicasts
			   and limited broadcast via necessary interface
			   without fiddling with IP_MULTICAST_IF or IP_PKTINFO.
			   This hack is not just for fun, it allows
			   vic,vat and friends to work.
			   They bind socket to loopback, set ttl to zero
			   and expect that it will work.
			   From the viewpoint of routing cache they are broken,
			   because we are not allowed to build multicast path
			   with loopback source addr (look, routing cache
			   cannot know, that ttl is zero, so that packet
			   will not leave this host and route is valid).
			   Luckily, this hack is good workaround.
			 */

			fl.oif = dev_out->ifindex;
			goto make_route;
		}
		if (dev_out)
			dev_put(dev_out);
		dev_out = NULL;
	}


	if (oldflp->oif) {
2331
		dev_out = dev_get_by_index(net, oldflp->oif);
L
Linus Torvalds 已提交
2332 2333 2334
		err = -ENODEV;
		if (dev_out == NULL)
			goto out;
2335 2336 2337

		/* RACE: Check return value of inet_select_addr instead. */
		if (__in_dev_get_rtnl(dev_out) == NULL) {
L
Linus Torvalds 已提交
2338 2339 2340 2341
			dev_put(dev_out);
			goto out;	/* Wrong error code */
		}

2342 2343
		if (ipv4_is_local_multicast(oldflp->fl4_dst) ||
		    oldflp->fl4_dst == htonl(0xFFFFFFFF)) {
L
Linus Torvalds 已提交
2344 2345 2346 2347 2348 2349
			if (!fl.fl4_src)
				fl.fl4_src = inet_select_addr(dev_out, 0,
							      RT_SCOPE_LINK);
			goto make_route;
		}
		if (!fl.fl4_src) {
2350
			if (ipv4_is_multicast(oldflp->fl4_dst))
L
Linus Torvalds 已提交
2351 2352 2353 2354 2355 2356 2357 2358 2359 2360 2361 2362 2363 2364
				fl.fl4_src = inet_select_addr(dev_out, 0,
							      fl.fl4_scope);
			else if (!oldflp->fl4_dst)
				fl.fl4_src = inet_select_addr(dev_out, 0,
							      RT_SCOPE_HOST);
		}
	}

	if (!fl.fl4_dst) {
		fl.fl4_dst = fl.fl4_src;
		if (!fl.fl4_dst)
			fl.fl4_dst = fl.fl4_src = htonl(INADDR_LOOPBACK);
		if (dev_out)
			dev_put(dev_out);
2365
		dev_out = net->loopback_dev;
L
Linus Torvalds 已提交
2366
		dev_hold(dev_out);
2367
		fl.oif = net->loopback_dev->ifindex;
L
Linus Torvalds 已提交
2368 2369 2370 2371 2372
		res.type = RTN_LOCAL;
		flags |= RTCF_LOCAL;
		goto make_route;
	}

2373
	if (fib_lookup(net, &fl, &res)) {
L
Linus Torvalds 已提交
2374 2375 2376 2377 2378 2379 2380 2381 2382 2383 2384 2385 2386 2387 2388 2389 2390 2391 2392 2393 2394 2395 2396 2397 2398 2399 2400 2401 2402 2403 2404 2405 2406 2407 2408 2409 2410 2411
		res.fi = NULL;
		if (oldflp->oif) {
			/* Apparently, routing tables are wrong. Assume,
			   that the destination is on link.

			   WHY? DW.
			   Because we are allowed to send to iface
			   even if it has NO routes and NO assigned
			   addresses. When oif is specified, routing
			   tables are looked up with only one purpose:
			   to catch if destination is gatewayed, rather than
			   direct. Moreover, if MSG_DONTROUTE is set,
			   we send packet, ignoring both routing tables
			   and ifaddr state. --ANK


			   We could make it even if oif is unknown,
			   likely IPv6, but we do not.
			 */

			if (fl.fl4_src == 0)
				fl.fl4_src = inet_select_addr(dev_out, 0,
							      RT_SCOPE_LINK);
			res.type = RTN_UNICAST;
			goto make_route;
		}
		if (dev_out)
			dev_put(dev_out);
		err = -ENETUNREACH;
		goto out;
	}
	free_res = 1;

	if (res.type == RTN_LOCAL) {
		if (!fl.fl4_src)
			fl.fl4_src = fl.fl4_dst;
		if (dev_out)
			dev_put(dev_out);
2412
		dev_out = net->loopback_dev;
L
Linus Torvalds 已提交
2413 2414 2415 2416 2417 2418 2419 2420 2421 2422 2423 2424 2425 2426 2427
		dev_hold(dev_out);
		fl.oif = dev_out->ifindex;
		if (res.fi)
			fib_info_put(res.fi);
		res.fi = NULL;
		flags |= RTCF_LOCAL;
		goto make_route;
	}

#ifdef CONFIG_IP_ROUTE_MULTIPATH
	if (res.fi->fib_nhs > 1 && fl.oif == 0)
		fib_select_multipath(&fl, &res);
	else
#endif
	if (!res.prefixlen && res.type == RTN_UNICAST && !fl.oif)
2428
		fib_select_default(net, &fl, &res);
L
Linus Torvalds 已提交
2429 2430 2431 2432 2433 2434 2435 2436 2437 2438 2439 2440 2441 2442 2443 2444 2445 2446 2447 2448 2449 2450

	if (!fl.fl4_src)
		fl.fl4_src = FIB_RES_PREFSRC(res);

	if (dev_out)
		dev_put(dev_out);
	dev_out = FIB_RES_DEV(res);
	dev_hold(dev_out);
	fl.oif = dev_out->ifindex;


make_route:
	err = ip_mkroute_output(rp, &res, &fl, oldflp, dev_out, flags);


	if (free_res)
		fib_res_put(&res);
	if (dev_out)
		dev_put(dev_out);
out:	return err;
}

2451 2452
int __ip_route_output_key(struct net *net, struct rtable **rp,
			  const struct flowi *flp)
L
Linus Torvalds 已提交
2453 2454 2455 2456
{
	unsigned hash;
	struct rtable *rth;

A
Al Viro 已提交
2457
	hash = rt_hash(flp->fl4_dst, flp->fl4_src, flp->oif);
L
Linus Torvalds 已提交
2458 2459 2460

	rcu_read_lock_bh();
	for (rth = rcu_dereference(rt_hash_table[hash].chain); rth;
2461
		rth = rcu_dereference(rth->u.dst.rt_next)) {
L
Linus Torvalds 已提交
2462 2463 2464 2465
		if (rth->fl.fl4_dst == flp->fl4_dst &&
		    rth->fl.fl4_src == flp->fl4_src &&
		    rth->fl.iif == 0 &&
		    rth->fl.oif == flp->oif &&
2466
		    rth->fl.mark == flp->mark &&
L
Linus Torvalds 已提交
2467
		    !((rth->fl.fl4_tos ^ flp->fl4_tos) &
2468
			    (IPTOS_RT_MASK | RTO_ONLINK)) &&
2469 2470
		    rth->u.dst.dev->nd_net == net &&
		    rth->rt_genid == atomic_read(&rt_genid)) {
2471
			dst_use(&rth->u.dst, jiffies);
L
Linus Torvalds 已提交
2472 2473 2474 2475 2476 2477 2478 2479 2480
			RT_CACHE_STAT_INC(out_hit);
			rcu_read_unlock_bh();
			*rp = rth;
			return 0;
		}
		RT_CACHE_STAT_INC(out_hlist_search);
	}
	rcu_read_unlock_bh();

2481
	return ip_route_output_slow(net, rp, flp);
L
Linus Torvalds 已提交
2482 2483
}

2484 2485
EXPORT_SYMBOL_GPL(__ip_route_output_key);

2486 2487 2488 2489 2490 2491 2492 2493 2494 2495 2496
static void ipv4_rt_blackhole_update_pmtu(struct dst_entry *dst, u32 mtu)
{
}

static struct dst_ops ipv4_dst_blackhole_ops = {
	.family			=	AF_INET,
	.protocol		=	__constant_htons(ETH_P_IP),
	.destroy		=	ipv4_dst_destroy,
	.check			=	ipv4_dst_check,
	.update_pmtu		=	ipv4_rt_blackhole_update_pmtu,
	.entry_size		=	sizeof(struct rtable),
2497
	.entries		=	ATOMIC_INIT(0),
2498 2499 2500 2501 2502 2503 2504 2505 2506 2507 2508 2509 2510 2511
};


static int ipv4_dst_blackhole(struct rtable **rp, struct flowi *flp, struct sock *sk)
{
	struct rtable *ort = *rp;
	struct rtable *rt = (struct rtable *)
		dst_alloc(&ipv4_dst_blackhole_ops);

	if (rt) {
		struct dst_entry *new = &rt->u.dst;

		atomic_set(&new->__refcnt, 1);
		new->__use = 1;
2512 2513
		new->input = dst_discard;
		new->output = dst_discard;
2514 2515 2516 2517 2518 2519 2520 2521 2522 2523 2524
		memcpy(new->metrics, ort->u.dst.metrics, RTAX_MAX*sizeof(u32));

		new->dev = ort->u.dst.dev;
		if (new->dev)
			dev_hold(new->dev);

		rt->fl = ort->fl;

		rt->idev = ort->idev;
		if (rt->idev)
			in_dev_hold(rt->idev);
2525
		rt->rt_genid = atomic_read(&rt_genid);
2526 2527 2528 2529 2530 2531 2532 2533 2534 2535 2536 2537 2538 2539 2540 2541 2542 2543 2544
		rt->rt_flags = ort->rt_flags;
		rt->rt_type = ort->rt_type;
		rt->rt_dst = ort->rt_dst;
		rt->rt_src = ort->rt_src;
		rt->rt_iif = ort->rt_iif;
		rt->rt_gateway = ort->rt_gateway;
		rt->rt_spec_dst = ort->rt_spec_dst;
		rt->peer = ort->peer;
		if (rt->peer)
			atomic_inc(&rt->peer->refcnt);

		dst_free(new);
	}

	dst_release(&(*rp)->u.dst);
	*rp = rt;
	return (rt ? 0 : -ENOMEM);
}

2545 2546
int ip_route_output_flow(struct net *net, struct rtable **rp, struct flowi *flp,
			 struct sock *sk, int flags)
L
Linus Torvalds 已提交
2547 2548 2549
{
	int err;

2550
	if ((err = __ip_route_output_key(net, rp, flp)) != 0)
L
Linus Torvalds 已提交
2551 2552 2553 2554 2555 2556 2557
		return err;

	if (flp->proto) {
		if (!flp->fl4_src)
			flp->fl4_src = (*rp)->rt_src;
		if (!flp->fl4_dst)
			flp->fl4_dst = (*rp)->rt_dst;
2558 2559
		err = __xfrm_lookup((struct dst_entry **)rp, flp, sk,
				    flags ? XFRM_LOOKUP_WAIT : 0);
2560 2561 2562 2563
		if (err == -EREMOTE)
			err = ipv4_dst_blackhole(rp, flp, sk);

		return err;
L
Linus Torvalds 已提交
2564 2565 2566 2567 2568
	}

	return 0;
}

2569 2570
EXPORT_SYMBOL_GPL(ip_route_output_flow);

2571
int ip_route_output_key(struct net *net, struct rtable **rp, struct flowi *flp)
L
Linus Torvalds 已提交
2572
{
2573
	return ip_route_output_flow(net, rp, flp, NULL, 0);
L
Linus Torvalds 已提交
2574 2575 2576
}

static int rt_fill_info(struct sk_buff *skb, u32 pid, u32 seq, int event,
2577
			int nowait, unsigned int flags)
L
Linus Torvalds 已提交
2578 2579 2580
{
	struct rtable *rt = (struct rtable*)skb->dst;
	struct rtmsg *r;
2581
	struct nlmsghdr *nlh;
2582 2583
	long expires;
	u32 id = 0, ts = 0, tsage = 0, error;
2584 2585 2586

	nlh = nlmsg_put(skb, pid, seq, event, sizeof(*r), flags);
	if (nlh == NULL)
2587
		return -EMSGSIZE;
2588 2589

	r = nlmsg_data(nlh);
L
Linus Torvalds 已提交
2590 2591 2592 2593 2594
	r->rtm_family	 = AF_INET;
	r->rtm_dst_len	= 32;
	r->rtm_src_len	= 0;
	r->rtm_tos	= rt->fl.fl4_tos;
	r->rtm_table	= RT_TABLE_MAIN;
2595
	NLA_PUT_U32(skb, RTA_TABLE, RT_TABLE_MAIN);
L
Linus Torvalds 已提交
2596 2597 2598 2599 2600 2601
	r->rtm_type	= rt->rt_type;
	r->rtm_scope	= RT_SCOPE_UNIVERSE;
	r->rtm_protocol = RTPROT_UNSPEC;
	r->rtm_flags	= (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED;
	if (rt->rt_flags & RTCF_NOTIFY)
		r->rtm_flags |= RTM_F_NOTIFY;
2602

2603
	NLA_PUT_BE32(skb, RTA_DST, rt->rt_dst);
2604

L
Linus Torvalds 已提交
2605 2606
	if (rt->fl.fl4_src) {
		r->rtm_src_len = 32;
2607
		NLA_PUT_BE32(skb, RTA_SRC, rt->fl.fl4_src);
L
Linus Torvalds 已提交
2608 2609
	}
	if (rt->u.dst.dev)
2610
		NLA_PUT_U32(skb, RTA_OIF, rt->u.dst.dev->ifindex);
L
Linus Torvalds 已提交
2611 2612
#ifdef CONFIG_NET_CLS_ROUTE
	if (rt->u.dst.tclassid)
2613
		NLA_PUT_U32(skb, RTA_FLOW, rt->u.dst.tclassid);
L
Linus Torvalds 已提交
2614 2615
#endif
	if (rt->fl.iif)
2616
		NLA_PUT_BE32(skb, RTA_PREFSRC, rt->rt_spec_dst);
L
Linus Torvalds 已提交
2617
	else if (rt->rt_src != rt->fl.fl4_src)
2618
		NLA_PUT_BE32(skb, RTA_PREFSRC, rt->rt_src);
2619

L
Linus Torvalds 已提交
2620
	if (rt->rt_dst != rt->rt_gateway)
2621
		NLA_PUT_BE32(skb, RTA_GATEWAY, rt->rt_gateway);
2622

L
Linus Torvalds 已提交
2623
	if (rtnetlink_put_metrics(skb, rt->u.dst.metrics) < 0)
2624 2625
		goto nla_put_failure;

2626 2627
	error = rt->u.dst.error;
	expires = rt->u.dst.expires ? rt->u.dst.expires - jiffies : 0;
L
Linus Torvalds 已提交
2628
	if (rt->peer) {
2629
		id = rt->peer->ip_id_count;
L
Linus Torvalds 已提交
2630
		if (rt->peer->tcp_ts_stamp) {
2631
			ts = rt->peer->tcp_ts;
2632
			tsage = get_seconds() - rt->peer->tcp_ts_stamp;
L
Linus Torvalds 已提交
2633 2634
		}
	}
2635

L
Linus Torvalds 已提交
2636 2637
	if (rt->fl.iif) {
#ifdef CONFIG_IP_MROUTE
2638
		__be32 dst = rt->rt_dst;
L
Linus Torvalds 已提交
2639

2640
		if (ipv4_is_multicast(dst) && !ipv4_is_local_multicast(dst) &&
2641
		    IPV4_DEVCONF_ALL(&init_net, MC_FORWARDING)) {
L
Linus Torvalds 已提交
2642 2643 2644 2645 2646
			int err = ipmr_get_route(skb, r, nowait);
			if (err <= 0) {
				if (!nowait) {
					if (err == 0)
						return 0;
2647
					goto nla_put_failure;
L
Linus Torvalds 已提交
2648 2649
				} else {
					if (err == -EMSGSIZE)
2650
						goto nla_put_failure;
2651
					error = err;
L
Linus Torvalds 已提交
2652 2653 2654 2655
				}
			}
		} else
#endif
2656
			NLA_PUT_U32(skb, RTA_IIF, rt->fl.iif);
L
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2657 2658
	}

2659 2660 2661
	if (rtnl_put_cacheinfo(skb, &rt->u.dst, id, ts, tsage,
			       expires, error) < 0)
		goto nla_put_failure;
2662 2663

	return nlmsg_end(skb, nlh);
L
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2664

2665
nla_put_failure:
2666 2667
	nlmsg_cancel(skb, nlh);
	return -EMSGSIZE;
L
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2668 2669
}

2670
static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr* nlh, void *arg)
L
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2671
{
2672
	struct net *net = in_skb->sk->sk_net;
2673 2674
	struct rtmsg *rtm;
	struct nlattr *tb[RTA_MAX+1];
L
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2675
	struct rtable *rt = NULL;
A
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2676 2677 2678
	__be32 dst = 0;
	__be32 src = 0;
	u32 iif;
2679
	int err;
L
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2680 2681
	struct sk_buff *skb;

2682 2683 2684
	if (net != &init_net)
		return -EINVAL;

2685 2686 2687 2688 2689 2690
	err = nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX, rtm_ipv4_policy);
	if (err < 0)
		goto errout;

	rtm = nlmsg_data(nlh);

L
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2691
	skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
2692 2693 2694 2695
	if (skb == NULL) {
		err = -ENOBUFS;
		goto errout;
	}
L
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2696 2697 2698 2699

	/* Reserve room for dummy headers, this skb can pass
	   through good chunk of routing engine.
	 */
2700
	skb_reset_mac_header(skb);
2701
	skb_reset_network_header(skb);
2702 2703

	/* Bugfix: need to give ip_route_input enough of an IP header to not gag. */
2704
	ip_hdr(skb)->protocol = IPPROTO_ICMP;
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	skb_reserve(skb, MAX_HEADER + sizeof(struct iphdr));

2707 2708
	src = tb[RTA_SRC] ? nla_get_be32(tb[RTA_SRC]) : 0;
	dst = tb[RTA_DST] ? nla_get_be32(tb[RTA_DST]) : 0;
2709
	iif = tb[RTA_IIF] ? nla_get_u32(tb[RTA_IIF]) : 0;
L
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2710 2711

	if (iif) {
2712 2713
		struct net_device *dev;

2714
		dev = __dev_get_by_index(&init_net, iif);
2715 2716 2717 2718 2719
		if (dev == NULL) {
			err = -ENODEV;
			goto errout_free;
		}

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2720 2721 2722 2723 2724
		skb->protocol	= htons(ETH_P_IP);
		skb->dev	= dev;
		local_bh_disable();
		err = ip_route_input(skb, dst, src, rtm->rtm_tos, dev);
		local_bh_enable();
2725 2726 2727

		rt = (struct rtable*) skb->dst;
		if (err == 0 && rt->u.dst.error)
L
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2728 2729
			err = -rt->u.dst.error;
	} else {
2730 2731 2732 2733 2734 2735 2736 2737 2738 2739
		struct flowi fl = {
			.nl_u = {
				.ip4_u = {
					.daddr = dst,
					.saddr = src,
					.tos = rtm->rtm_tos,
				},
			},
			.oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0,
		};
2740
		err = ip_route_output_key(&init_net, &rt, &fl);
L
Linus Torvalds 已提交
2741
	}
2742

L
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2743
	if (err)
2744
		goto errout_free;
L
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2745 2746 2747 2748 2749 2750

	skb->dst = &rt->u.dst;
	if (rtm->rtm_flags & RTM_F_NOTIFY)
		rt->rt_flags |= RTCF_NOTIFY;

	err = rt_fill_info(skb, NETLINK_CB(in_skb).pid, nlh->nlmsg_seq,
2751
				RTM_NEWROUTE, 0, 0);
2752 2753
	if (err <= 0)
		goto errout_free;
L
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2754

2755
	err = rtnl_unicast(skb, &init_net, NETLINK_CB(in_skb).pid);
2756
errout:
2757
	return err;
L
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2758

2759
errout_free:
L
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2760
	kfree_skb(skb);
2761
	goto errout;
L
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2762 2763 2764 2765 2766 2767 2768 2769 2770
}

int ip_rt_dump(struct sk_buff *skb,  struct netlink_callback *cb)
{
	struct rtable *rt;
	int h, s_h;
	int idx, s_idx;

	s_h = cb->args[0];
2771 2772
	if (s_h < 0)
		s_h = 0;
L
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2773
	s_idx = idx = cb->args[1];
2774
	for (h = s_h; h <= rt_hash_mask; h++) {
L
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2775 2776
		rcu_read_lock_bh();
		for (rt = rcu_dereference(rt_hash_table[h].chain), idx = 0; rt;
2777
		     rt = rcu_dereference(rt->u.dst.rt_next), idx++) {
L
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2778 2779
			if (idx < s_idx)
				continue;
2780 2781
			if (rt->rt_genid != atomic_read(&rt_genid))
				continue;
L
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2782 2783
			skb->dst = dst_clone(&rt->u.dst);
			if (rt_fill_info(skb, NETLINK_CB(cb->skb).pid,
2784
					 cb->nlh->nlmsg_seq, RTM_NEWROUTE,
2785
					 1, NLM_F_MULTI) <= 0) {
L
Linus Torvalds 已提交
2786 2787 2788 2789 2790 2791 2792
				dst_release(xchg(&skb->dst, NULL));
				rcu_read_unlock_bh();
				goto done;
			}
			dst_release(xchg(&skb->dst, NULL));
		}
		rcu_read_unlock_bh();
2793
		s_idx = 0;
L
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2794 2795 2796 2797 2798 2799 2800 2801 2802 2803 2804 2805 2806 2807 2808 2809 2810 2811 2812 2813 2814 2815 2816 2817
	}

done:
	cb->args[0] = h;
	cb->args[1] = idx;
	return skb->len;
}

void ip_rt_multicast_event(struct in_device *in_dev)
{
	rt_cache_flush(0);
}

#ifdef CONFIG_SYSCTL
static int flush_delay;

static int ipv4_sysctl_rtcache_flush(ctl_table *ctl, int write,
					struct file *filp, void __user *buffer,
					size_t *lenp, loff_t *ppos)
{
	if (write) {
		proc_dointvec(ctl, write, filp, buffer, lenp, ppos);
		rt_cache_flush(flush_delay);
		return 0;
2818
	}
L
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2819 2820 2821 2822 2823 2824 2825 2826 2827 2828

	return -EINVAL;
}

static int ipv4_sysctl_rtcache_flush_strategy(ctl_table *table,
						int __user *name,
						int nlen,
						void __user *oldval,
						size_t __user *oldlenp,
						void __user *newval,
2829
						size_t newlen)
L
Linus Torvalds 已提交
2830 2831 2832 2833 2834
{
	int delay;
	if (newlen != sizeof(int))
		return -EINVAL;
	if (get_user(delay, (int __user *)newval))
2835 2836
		return -EFAULT;
	rt_cache_flush(delay);
L
Linus Torvalds 已提交
2837 2838 2839 2840
	return 0;
}

ctl_table ipv4_route_table[] = {
2841
	{
L
Linus Torvalds 已提交
2842 2843 2844 2845
		.ctl_name 	= NET_IPV4_ROUTE_FLUSH,
		.procname	= "flush",
		.data		= &flush_delay,
		.maxlen		= sizeof(int),
2846
		.mode		= 0200,
L
Linus Torvalds 已提交
2847 2848 2849 2850 2851 2852 2853 2854 2855 2856 2857 2858 2859 2860 2861 2862 2863 2864 2865 2866 2867
		.proc_handler	= &ipv4_sysctl_rtcache_flush,
		.strategy	= &ipv4_sysctl_rtcache_flush_strategy,
	},
	{
		.ctl_name	= NET_IPV4_ROUTE_GC_THRESH,
		.procname	= "gc_thresh",
		.data		= &ipv4_dst_ops.gc_thresh,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec,
	},
	{
		.ctl_name	= NET_IPV4_ROUTE_MAX_SIZE,
		.procname	= "max_size",
		.data		= &ip_rt_max_size,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec,
	},
	{
		/*  Deprecated. Use gc_min_interval_ms */
2868

L
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2869 2870 2871 2872 2873 2874 2875 2876 2877 2878 2879 2880 2881 2882 2883 2884 2885 2886 2887 2888 2889 2890 2891 2892 2893 2894 2895 2896 2897 2898 2899 2900 2901 2902 2903 2904 2905 2906 2907 2908 2909 2910 2911 2912 2913 2914 2915 2916 2917 2918 2919 2920 2921 2922 2923 2924 2925 2926 2927 2928 2929 2930 2931 2932 2933 2934 2935 2936 2937 2938 2939 2940 2941 2942 2943 2944 2945 2946 2947 2948 2949 2950 2951 2952 2953 2954 2955 2956 2957 2958 2959 2960 2961 2962 2963 2964 2965 2966 2967 2968 2969 2970 2971 2972 2973 2974 2975 2976 2977 2978 2979 2980 2981 2982 2983 2984 2985 2986 2987 2988 2989 2990
		.ctl_name	= NET_IPV4_ROUTE_GC_MIN_INTERVAL,
		.procname	= "gc_min_interval",
		.data		= &ip_rt_gc_min_interval,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec_jiffies,
		.strategy	= &sysctl_jiffies,
	},
	{
		.ctl_name	= NET_IPV4_ROUTE_GC_MIN_INTERVAL_MS,
		.procname	= "gc_min_interval_ms",
		.data		= &ip_rt_gc_min_interval,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec_ms_jiffies,
		.strategy	= &sysctl_ms_jiffies,
	},
	{
		.ctl_name	= NET_IPV4_ROUTE_GC_TIMEOUT,
		.procname	= "gc_timeout",
		.data		= &ip_rt_gc_timeout,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec_jiffies,
		.strategy	= &sysctl_jiffies,
	},
	{
		.ctl_name	= NET_IPV4_ROUTE_GC_INTERVAL,
		.procname	= "gc_interval",
		.data		= &ip_rt_gc_interval,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec_jiffies,
		.strategy	= &sysctl_jiffies,
	},
	{
		.ctl_name	= NET_IPV4_ROUTE_REDIRECT_LOAD,
		.procname	= "redirect_load",
		.data		= &ip_rt_redirect_load,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec,
	},
	{
		.ctl_name	= NET_IPV4_ROUTE_REDIRECT_NUMBER,
		.procname	= "redirect_number",
		.data		= &ip_rt_redirect_number,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec,
	},
	{
		.ctl_name	= NET_IPV4_ROUTE_REDIRECT_SILENCE,
		.procname	= "redirect_silence",
		.data		= &ip_rt_redirect_silence,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec,
	},
	{
		.ctl_name	= NET_IPV4_ROUTE_ERROR_COST,
		.procname	= "error_cost",
		.data		= &ip_rt_error_cost,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec,
	},
	{
		.ctl_name	= NET_IPV4_ROUTE_ERROR_BURST,
		.procname	= "error_burst",
		.data		= &ip_rt_error_burst,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec,
	},
	{
		.ctl_name	= NET_IPV4_ROUTE_GC_ELASTICITY,
		.procname	= "gc_elasticity",
		.data		= &ip_rt_gc_elasticity,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec,
	},
	{
		.ctl_name	= NET_IPV4_ROUTE_MTU_EXPIRES,
		.procname	= "mtu_expires",
		.data		= &ip_rt_mtu_expires,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec_jiffies,
		.strategy	= &sysctl_jiffies,
	},
	{
		.ctl_name	= NET_IPV4_ROUTE_MIN_PMTU,
		.procname	= "min_pmtu",
		.data		= &ip_rt_min_pmtu,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec,
	},
	{
		.ctl_name	= NET_IPV4_ROUTE_MIN_ADVMSS,
		.procname	= "min_adv_mss",
		.data		= &ip_rt_min_advmss,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec,
	},
	{
		.ctl_name	= NET_IPV4_ROUTE_SECRET_INTERVAL,
		.procname	= "secret_interval",
		.data		= &ip_rt_secret_interval,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec_jiffies,
		.strategy	= &sysctl_jiffies,
	},
	{ .ctl_name = 0 }
};
#endif

#ifdef CONFIG_NET_CLS_ROUTE
2991
struct ip_rt_acct *ip_rt_acct __read_mostly;
L
Linus Torvalds 已提交
2992 2993 2994 2995 2996 2997 2998 2999 3000 3001 3002 3003 3004 3005
#endif /* CONFIG_NET_CLS_ROUTE */

static __initdata unsigned long rhash_entries;
static int __init set_rhash_entries(char *str)
{
	if (!str)
		return 0;
	rhash_entries = simple_strtoul(str, &str, 0);
	return 1;
}
__setup("rhash_entries=", set_rhash_entries);

int __init ip_rt_init(void)
{
3006
	int rc = 0;
L
Linus Torvalds 已提交
3007

3008 3009
	atomic_set(&rt_genid, (int) ((num_physpages ^ (num_physpages>>8)) ^
			     (jiffies ^ (jiffies >> 7))));
L
Linus Torvalds 已提交
3010 3011

#ifdef CONFIG_NET_CLS_ROUTE
3012
	ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct));
L
Linus Torvalds 已提交
3013 3014 3015 3016
	if (!ip_rt_acct)
		panic("IP: failed to allocate ip_rt_acct\n");
#endif

A
Alexey Dobriyan 已提交
3017 3018
	ipv4_dst_ops.kmem_cachep =
		kmem_cache_create("ip_dst_cache", sizeof(struct rtable), 0,
3019
				  SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
L
Linus Torvalds 已提交
3020

3021 3022
	ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep;

3023 3024 3025 3026 3027
	rt_hash_table = (struct rt_hash_bucket *)
		alloc_large_system_hash("IP route cache",
					sizeof(struct rt_hash_bucket),
					rhash_entries,
					(num_physpages >= 128 * 1024) ?
3028
					15 : 17,
3029
					0,
3030 3031 3032
					&rt_hash_log,
					&rt_hash_mask,
					0);
3033 3034
	memset(rt_hash_table, 0, (rt_hash_mask + 1) * sizeof(struct rt_hash_bucket));
	rt_hash_lock_init();
L
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3035 3036 3037 3038 3039 3040 3041

	ipv4_dst_ops.gc_thresh = (rt_hash_mask + 1);
	ip_rt_max_size = (rt_hash_mask + 1) * 16;

	devinet_init();
	ip_fib_init();

3042
	setup_timer(&rt_secret_timer, rt_secret_rebuild, 0);
L
Linus Torvalds 已提交
3043 3044 3045 3046

	/* All the timers, started at system startup tend
	   to synchronize. Perturb it a bit.
	 */
3047 3048
	schedule_delayed_work(&expires_work,
		net_random() % ip_rt_gc_interval + ip_rt_gc_interval);
L
Linus Torvalds 已提交
3049 3050 3051 3052 3053

	rt_secret_timer.expires = jiffies + net_random() % ip_rt_secret_interval +
		ip_rt_secret_interval;
	add_timer(&rt_secret_timer);

3054 3055
	if (ip_rt_proc_init(&init_net))
		printk(KERN_ERR "Unable to create route proc files\n");
L
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3056 3057 3058 3059
#ifdef CONFIG_XFRM
	xfrm_init();
	xfrm4_init();
#endif
3060 3061
	rtnl_register(PF_INET, RTM_GETROUTE, inet_rtm_getroute, NULL);

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3062 3063 3064 3065 3066 3067
	return rc;
}

EXPORT_SYMBOL(__ip_select_ident);
EXPORT_SYMBOL(ip_route_input);
EXPORT_SYMBOL(ip_route_output_key);