route.c 77.9 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>
#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>
#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>
#include <net/ip_mp_alg.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_min_delay		= 2 * HZ;
static int ip_rt_max_delay		= 10 * 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;
static unsigned long rt_deadline;

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

static struct timer_list rt_flush_timer;
static struct timer_list rt_periodic_timer;
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);
static int rt_garbage_collect(void);


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,
	.entry_size =		sizeof(struct rtable),
};

#define ECN_OR_COST(class)	TC_PRIO_##class

__u8 ip_tos2prio[16] = {
	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)]
# define rt_hash_lock_init()	{ \
		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]); \
		}
#else
# define rt_hash_lock_addr(slot) NULL
# define rt_hash_lock_init()
#endif
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static struct rt_hash_bucket 	*rt_hash_table;
static unsigned			rt_hash_mask;
static int			rt_hash_log;
static unsigned int		rt_hash_rnd;

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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 int rt_intern_hash(unsigned hash, struct rtable *rth,
				struct rtable **res);

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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, rt_hash_rnd)
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		& rt_hash_mask);
}

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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;
};

static struct rtable *rt_cache_get_first(struct seq_file *seq)
{
	struct rtable *r = NULL;
	struct rt_cache_iter_state *st = seq->private;

	for (st->bucket = rt_hash_mask; st->bucket >= 0; --st->bucket) {
		rcu_read_lock_bh();
		r = rt_hash_table[st->bucket].chain;
		if (r)
			break;
		rcu_read_unlock_bh();
	}
	return r;
}

static struct rtable *rt_cache_get_next(struct seq_file *seq, struct rtable *r)
{
	struct rt_cache_iter_state *st = rcu_dereference(seq->private);

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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;
	}
	return r;
}

static struct rtable *rt_cache_get_idx(struct seq_file *seq, loff_t pos)
{
	struct rtable *r = rt_cache_get_first(seq);

	if (r)
		while (pos && (r = rt_cache_get_next(seq, r)))
			--pos;
	return pos ? NULL : r;
}

static void *rt_cache_seq_start(struct seq_file *seq, loff_t *pos)
{
	return *pos ? rt_cache_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
}

static void *rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
	struct rtable *r = NULL;

	if (v == SEQ_START_TOKEN)
		r = rt_cache_get_first(seq);
	else
		r = rt_cache_get_next(seq, v);
	++*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)
{
	struct seq_file *seq;
	int rc = -ENOMEM;
	struct rt_cache_iter_state *s = kmalloc(sizeof(*s), GFP_KERNEL);

	if (!s)
		goto out;
	rc = seq_open(file, &rt_cache_seq_ops);
	if (rc)
		goto out_kfree;
	seq          = file->private_data;
	seq->private = s;
	memset(s, 0, sizeof(*s));
out:
	return rc;
out_kfree:
	kfree(s);
	goto out;
}

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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,
};

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

static __inline__ void rt_drop(struct rtable *rt)
{
	multipath_remove(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)) &&
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		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)
{
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	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)) |
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		(fl1->mark ^ fl2->mark) |
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		(*(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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}

#ifdef CONFIG_IP_ROUTE_MULTIPATH_CACHED
static struct rtable **rt_remove_balanced_route(struct rtable **chain_head,
						struct rtable *expentry,
						int *removed_count)
{
	int passedexpired = 0;
	struct rtable **nextstep = NULL;
	struct rtable **rthp = chain_head;
	struct rtable *rth;

	if (removed_count)
		*removed_count = 0;

	while ((rth = *rthp) != NULL) {
		if (rth == expentry)
			passedexpired = 1;

		if (((*rthp)->u.dst.flags & DST_BALANCED) != 0  &&
		    compare_keys(&(*rthp)->fl, &expentry->fl)) {
			if (*rthp == expentry) {
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				*rthp = rth->u.dst.rt_next;
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				continue;
			} else {
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				*rthp = rth->u.dst.rt_next;
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				rt_free(rth);
				if (removed_count)
					++(*removed_count);
			}
		} else {
			if (!((*rthp)->u.dst.flags & DST_BALANCED) &&
			    passedexpired && !nextstep)
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				nextstep = &rth->u.dst.rt_next;
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			rthp = &rth->u.dst.rt_next;
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		}
	}

	rt_free(expentry);
	if (removed_count)
		++(*removed_count);

	return nextstep;
}
#endif /* CONFIG_IP_ROUTE_MULTIPATH_CACHED */


/* This runs via a timer and thus is always in BH context. */
static void rt_check_expire(unsigned long dummy)
{
626 627
	static unsigned int rover;
	unsigned int i = rover, goal;
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	struct rtable *rth, **rthp;
	unsigned long now = jiffies;
630 631 632 633 634 635 636 637
	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;
	if (goal > rt_hash_mask) goal = rt_hash_mask + 1;
	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;

643 644
		if (*rthp == 0)
			continue;
645
		spin_lock(rt_hash_lock_addr(i));
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		while ((rth = *rthp) != NULL) {
			if (rth->u.dst.expires) {
				/* Entry is expired even if it is in use */
				if (time_before_eq(now, rth->u.dst.expires)) {
					tmo >>= 1;
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					rthp = &rth->u.dst.rt_next;
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					continue;
				}
			} else if (!rt_may_expire(rth, tmo, ip_rt_gc_timeout)) {
				tmo >>= 1;
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				rthp = &rth->u.dst.rt_next;
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				continue;
			}

			/* Cleanup aged off entries. */
#ifdef CONFIG_IP_ROUTE_MULTIPATH_CACHED
			/* remove all related balanced entries if necessary */
			if (rth->u.dst.flags & DST_BALANCED) {
				rthp = rt_remove_balanced_route(
					&rt_hash_table[i].chain,
					rth, NULL);
				if (!rthp)
					break;
			} else {
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				*rthp = rth->u.dst.rt_next;
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				rt_free(rth);
			}
#else /* CONFIG_IP_ROUTE_MULTIPATH_CACHED */
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			*rthp = rth->u.dst.rt_next;
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			rt_free(rth);
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#endif /* CONFIG_IP_ROUTE_MULTIPATH_CACHED */
		}
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		spin_unlock(rt_hash_lock_addr(i));
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		/* Fallback loop breaker. */
		if (time_after(jiffies, now))
			break;
	}
	rover = i;
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	mod_timer(&rt_periodic_timer, jiffies + ip_rt_gc_interval);
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}

/* This can run from both BH and non-BH contexts, the latter
 * in the case of a forced flush event.
 */
static void rt_run_flush(unsigned long dummy)
{
	int i;
	struct rtable *rth, *next;

	rt_deadline = 0;

	get_random_bytes(&rt_hash_rnd, 4);

	for (i = rt_hash_mask; i >= 0; i--) {
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		spin_lock_bh(rt_hash_lock_addr(i));
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		rth = rt_hash_table[i].chain;
		if (rth)
			rt_hash_table[i].chain = NULL;
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		spin_unlock_bh(rt_hash_lock_addr(i));
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		for (; rth; rth = next) {
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			next = rth->u.dst.rt_next;
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			rt_free(rth);
		}
	}
}

static DEFINE_SPINLOCK(rt_flush_lock);

void rt_cache_flush(int delay)
{
	unsigned long now = jiffies;
	int user_mode = !in_softirq();

	if (delay < 0)
		delay = ip_rt_min_delay;

	/* flush existing multipath state*/
	multipath_flush();

	spin_lock_bh(&rt_flush_lock);

	if (del_timer(&rt_flush_timer) && delay > 0 && rt_deadline) {
		long tmo = (long)(rt_deadline - now);

		/* If flush timer is already running
		   and flush request is not immediate (delay > 0):

		   if deadline is not achieved, prolongate timer to "delay",
		   otherwise fire it at deadline time.
		 */

		if (user_mode && tmo < ip_rt_max_delay-ip_rt_min_delay)
			tmo = 0;
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		if (delay > tmo)
			delay = tmo;
	}

	if (delay <= 0) {
		spin_unlock_bh(&rt_flush_lock);
		rt_run_flush(0);
		return;
	}

	if (rt_deadline == 0)
		rt_deadline = now + ip_rt_max_delay;

	mod_timer(&rt_flush_timer, now+delay);
	spin_unlock_bh(&rt_flush_lock);
}

static void rt_secret_rebuild(unsigned long dummy)
{
	unsigned long now = jiffies;

	rt_cache_flush(0);
	mod_timer(&rt_secret_timer, now + ip_rt_secret_interval);
}

/*
   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.
 */

static int rt_garbage_collect(void)
{
	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) {
			equilibrium += min_t(unsigned int, goal / 2, rt_hash_mask + 1);
			goal = atomic_read(&ipv4_dst_ops.entries) - equilibrium;
		}
	} else {
		/* We are in dangerous area. Try to reduce cache really
		 * aggressively.
		 */
		goal = max_t(unsigned int, goal / 2, rt_hash_mask + 1);
		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;
838
			spin_lock_bh(rt_hash_lock_addr(k));
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			while ((rth = *rthp) != NULL) {
				if (!rt_may_expire(rth, tmo, expire)) {
					tmo >>= 1;
842
					rthp = &rth->u.dst.rt_next;
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					continue;
				}
#ifdef CONFIG_IP_ROUTE_MULTIPATH_CACHED
				/* remove all related balanced entries
				 * if necessary
				 */
				if (rth->u.dst.flags & DST_BALANCED) {
					int r;

					rthp = rt_remove_balanced_route(
853
						&rt_hash_table[k].chain,
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						rth,
						&r);
					goal -= r;
					if (!rthp)
						break;
				} else {
860
					*rthp = rth->u.dst.rt_next;
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					rt_free(rth);
					goal--;
				}
#else /* CONFIG_IP_ROUTE_MULTIPATH_CACHED */
865
				*rthp = rth->u.dst.rt_next;
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				rt_free(rth);
				goal--;
#endif /* CONFIG_IP_ROUTE_MULTIPATH_CACHED */
			}
870
			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;

940
	spin_lock_bh(rt_hash_lock_addr(hash));
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	while ((rth = *rthp) != NULL) {
#ifdef CONFIG_IP_ROUTE_MULTIPATH_CACHED
		if (!(rth->u.dst.flags & DST_BALANCED) &&
		    compare_keys(&rth->fl, &rt->fl)) {
#else
		if (compare_keys(&rth->fl, &rt->fl)) {
#endif
			/* Put it first */
949
			*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.
			 */
955
			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);

			rth->u.dst.__use++;
			dst_hold(&rth->u.dst);
			rth->u.dst.lastuse = now;
966
			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++;

985
		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) {
996
			*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) {
1007
			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;
				rt_garbage_collect();
				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;
		}
	}

1036
	rt->u.dst.rt_next = rt_hash_table[hash].chain;
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#if RT_CACHE_DEBUG >= 2
1038
	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));
1042
		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;
1048
	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);
1084
	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
1106
		printk(KERN_DEBUG "rt_bind_peer(0) @%p\n",
1107
		       __builtin_return_address(0));
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	ip_select_fb_ident(iph);
}

static void rt_del(unsigned hash, struct rtable *rt)
{
	struct rtable **rthp;

1116
	spin_lock_bh(rt_hash_lock_addr(hash));
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	ip_rt_put(rt);
	for (rthp = &rt_hash_table[hash].chain; *rthp;
1119
	     rthp = &(*rthp)->u.dst.rt_next)
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		if (*rthp == rt) {
1121
			*rthp = rt->u.dst.rt_next;
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			rt_free(rt);
			break;
		}
1125
	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 };
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	struct netevent_redirect netevent;
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	if (!in_dev)
		return;

	if (new_gw == old_gw || !IN_DEV_RX_REDIRECTS(in_dev)
	    || MULTICAST(new_gw) || BADCLASS(new_gw) || ZERONET(new_gw))
		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 {
		if (inet_addr_type(new_gw) != RTN_UNICAST)
			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] ||
				    rth->fl.iif != 0) {
1169
					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;
1192
				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;

				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;
				}
1227

1228 1229
				netevent.old = &rth->u.dst;
				netevent.new = &rt->u.dst;
1230 1231
				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"
1251
			"  Advised path = %u.%u.%u.%u -> %u.%u.%u.%u\n",
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		       NIPQUAD(old_gw), dev->name, NIPQUAD(new_gw),
1253
		       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
			printk(KERN_DEBUG "ip_rt_advice: redirect to "
					  "%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.
	 */
1327 1328
	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:
1345
	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;
			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;
1381
}
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/*
 *	The last two values are not from the RFC but
 *	are needed for AMPRnet AX.25 paths.
 */

1388
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;
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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;
}

unsigned short ip_rt_frag_needed(struct iphdr *iph, unsigned short new_mtu)
{
	int i;
	unsigned short old_mtu = ntohs(iph->tot_len);
	struct rtable *rth;
1406 1407
	__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;
1418
		     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 &&
			    !(dst_metric_locked(&rth->u.dst, RTAX_MTU))) {
				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]) {
1438
					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);
1468
		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;
	if (dev != &loopback_dev && idev && idev->dev == dev) {
		struct in_device *loopback_idev = in_dev_get(&loopback_dev);
		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",
1522
		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;
	else if (fib_lookup(&rt->fl, &res) == 0) {
		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
1602
	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;

	if (MULTICAST(saddr) || BADCLASS(saddr) || LOOPBACK(saddr) ||
	    skb->protocol != htons(ETH_P_IP))
		goto e_inval;

	if (ZERONET(saddr)) {
		if (!LOCAL_MCAST(daddr))
			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;
	if (in_dev->cnf.no_policy)
		rth->u.dst.flags |= DST_NOPOLICY;
	rth->fl.fl4_dst	= daddr;
	rth->rt_dst	= daddr;
	rth->fl.fl4_tos	= tos;
1644
	rth->fl.mark    = skb->mark;
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	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;
	rth->u.dst.dev	= &loopback_dev;
	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;
	rth->rt_type	= RTN_MULTICAST;
	rth->rt_flags	= RTCF_MULTICAST;
	if (our) {
		rth->u.dst.input= ip_local_deliver;
		rth->rt_flags |= RTCF_LOCAL;
	}

#ifdef CONFIG_IP_MROUTE
	if (!LOCAL_MCAST(daddr) && IN_DEV_MFORWARD(in_dev))
		rth->u.dst.input = ip_mr_input;
#endif
	RT_CACHE_STAT_INC(in_slow_mc);

	in_dev_put(in_dev);
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	hash = rt_hash(daddr, saddr, dev->ifindex);
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	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
1688 1689
				     __be32 daddr,
				     __be32 saddr)
L
Linus Torvalds 已提交
1690 1691 1692 1693 1694 1695 1696 1697 1698 1699 1700
{
	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);
1701
		if (dev->hard_header_len && skb_mac_header_was_set(skb)) {
L
Linus Torvalds 已提交
1702
			int i;
1703
			const unsigned char *p = skb_mac_header(skb);
L
Linus Torvalds 已提交
1704 1705 1706 1707 1708 1709 1710 1711 1712 1713 1714 1715
			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
}

1716 1717 1718
static inline int __mkroute_input(struct sk_buff *skb,
				  struct fib_result* res,
				  struct in_device *in_dev,
A
Al Viro 已提交
1719
				  __be32 daddr, __be32 saddr, u32 tos,
1720
				  struct rtable **result)
L
Linus Torvalds 已提交
1721 1722 1723 1724 1725 1726
{

	struct rtable *rth;
	int err;
	struct in_device *out_dev;
	unsigned flags = 0;
1727 1728
	__be32 spec_dst;
	u32 itag;
L
Linus Torvalds 已提交
1729 1730 1731 1732 1733 1734 1735 1736 1737 1738 1739

	/* 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;
	}


1740
	err = fib_validate_source(saddr, daddr, tos, FIB_RES_OIF(*res),
L
Linus Torvalds 已提交
1741 1742
				  in_dev->dev, &spec_dst, &itag);
	if (err < 0) {
1743
		ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr,
L
Linus Torvalds 已提交
1744
					 saddr);
1745

L
Linus Torvalds 已提交
1746 1747 1748 1749 1750 1751 1752 1753 1754 1755 1756 1757 1758 1759 1760 1761 1762 1763 1764 1765 1766 1767 1768 1769 1770 1771 1772 1773 1774
		err = -EINVAL;
		goto cleanup;
	}

	if (err)
		flags |= RTCF_DIRECTSRC;

	if (out_dev == in_dev && err && !(flags & (RTCF_NAT | RTCF_MASQ)) &&
	    (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.
		 */
		if (out_dev == in_dev && !(flags & RTCF_DNAT)) {
			err = -EINVAL;
			goto cleanup;
		}
	}


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

1775
	atomic_set(&rth->u.dst.__refcnt, 1);
L
Linus Torvalds 已提交
1776 1777 1778 1779 1780 1781 1782
	rth->u.dst.flags= DST_HOST;
#ifdef CONFIG_IP_ROUTE_MULTIPATH_CACHED
	if (res->fi->fib_nhs > 1)
		rth->u.dst.flags |= DST_BALANCED;
#endif
	if (in_dev->cnf.no_policy)
		rth->u.dst.flags |= DST_NOPOLICY;
1783
	if (out_dev->cnf.no_xfrm)
L
Linus Torvalds 已提交
1784 1785 1786 1787
		rth->u.dst.flags |= DST_NOXFRM;
	rth->fl.fl4_dst	= daddr;
	rth->rt_dst	= daddr;
	rth->fl.fl4_tos	= tos;
1788
	rth->fl.mark    = skb->mark;
L
Linus Torvalds 已提交
1789 1790 1791 1792 1793 1794 1795 1796 1797 1798 1799 1800 1801 1802 1803 1804 1805 1806 1807 1808 1809 1810 1811 1812
	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;

	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;
1813
}
L
Linus Torvalds 已提交
1814

1815 1816
static inline int ip_mkroute_input_def(struct sk_buff *skb,
				       struct fib_result* res,
L
Linus Torvalds 已提交
1817 1818
				       const struct flowi *fl,
				       struct in_device *in_dev,
A
Al Viro 已提交
1819
				       __be32 daddr, __be32 saddr, u32 tos)
L
Linus Torvalds 已提交
1820
{
C
Chuck Short 已提交
1821
	struct rtable* rth = NULL;
L
Linus Torvalds 已提交
1822 1823 1824 1825 1826 1827 1828 1829 1830 1831 1832 1833 1834 1835
	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
1836
	hash = rt_hash(daddr, saddr, fl->iif);
1837
	return rt_intern_hash(hash, rth, (struct rtable**)&skb->dst);
L
Linus Torvalds 已提交
1838 1839
}

1840 1841
static inline int ip_mkroute_input(struct sk_buff *skb,
				   struct fib_result* res,
L
Linus Torvalds 已提交
1842 1843
				   const struct flowi *fl,
				   struct in_device *in_dev,
A
Al Viro 已提交
1844
				   __be32 daddr, __be32 saddr, u32 tos)
L
Linus Torvalds 已提交
1845 1846
{
#ifdef CONFIG_IP_ROUTE_MULTIPATH_CACHED
1847 1848
	struct rtable* rth = NULL, *rtres;
	unsigned char hop, hopcount;
L
Linus Torvalds 已提交
1849 1850 1851 1852 1853 1854 1855 1856 1857 1858 1859 1860
	int err = -EINVAL;
	unsigned int hash;

	if (res->fi)
		hopcount = res->fi->fib_nhs;
	else
		hopcount = 1;

	/* distinguish between multipath and singlepath */
	if (hopcount < 2)
		return ip_mkroute_input_def(skb, res, fl, in_dev, daddr,
					    saddr, tos);
1861

L
Linus Torvalds 已提交
1862 1863 1864 1865
	/* add all alternatives to the routing cache */
	for (hop = 0; hop < hopcount; hop++) {
		res->nh_sel = hop;

1866 1867 1868 1869
		/* put reference to previous result */
		if (hop)
			ip_rt_put(rtres);

L
Linus Torvalds 已提交
1870 1871 1872 1873 1874 1875 1876
		/* 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
1877
		hash = rt_hash(daddr, saddr, fl->iif);
1878
		err = rt_intern_hash(hash, rth, &rtres);
L
Linus Torvalds 已提交
1879 1880 1881 1882 1883 1884 1885 1886 1887 1888
		if (err)
			return err;

		/* forward hop information to multipath impl. */
		multipath_set_nhinfo(rth,
				     FIB_RES_NETWORK(*res),
				     FIB_RES_NETMASK(*res),
				     res->prefixlen,
				     &FIB_RES_NH(*res));
	}
1889
	skb->dst = &rtres->u.dst;
L
Linus Torvalds 已提交
1890 1891 1892 1893 1894 1895 1896 1897 1898 1899 1900 1901 1902 1903 1904 1905 1906
	return err;
#else /* CONFIG_IP_ROUTE_MULTIPATH_CACHED  */
	return ip_mkroute_input_def(skb, res, fl, in_dev, daddr, saddr, tos);
#endif /* CONFIG_IP_ROUTE_MULTIPATH_CACHED  */
}


/*
 *	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
1907
static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
L
Linus Torvalds 已提交
1908 1909 1910 1911 1912 1913 1914 1915 1916 1917
			       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,
				      } },
1918
			    .mark = skb->mark,
L
Linus Torvalds 已提交
1919 1920 1921 1922 1923
			    .iif = dev->ifindex };
	unsigned	flags = 0;
	u32		itag = 0;
	struct rtable * rth;
	unsigned	hash;
A
Al Viro 已提交
1924
	__be32		spec_dst;
L
Linus Torvalds 已提交
1925 1926 1927 1928 1929 1930 1931 1932 1933 1934 1935 1936 1937 1938 1939
	int		err = -EINVAL;
	int		free_res = 0;

	/* 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.
	 */

	if (MULTICAST(saddr) || BADCLASS(saddr) || LOOPBACK(saddr))
		goto martian_source;

1940
	if (daddr == htonl(0xFFFFFFFF) || (saddr == 0 && daddr == 0))
L
Linus Torvalds 已提交
1941 1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956
		goto brd_input;

	/* Accept zero addresses only to limited broadcast;
	 * I even do not know to fix it or not. Waiting for complains :-)
	 */
	if (ZERONET(saddr))
		goto martian_source;

	if (BADCLASS(daddr) || ZERONET(daddr) || LOOPBACK(daddr))
		goto martian_destination;

	/*
	 *	Now we are ready to route packet.
	 */
	if ((err = fib_lookup(&fl, &res)) != 0) {
		if (!IN_DEV_FORWARD(in_dev))
1957
			goto e_hostunreach;
L
Linus Torvalds 已提交
1958 1959 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980
		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,
					     loopback_dev.ifindex,
					     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))
1981
		goto e_hostunreach;
L
Linus Torvalds 已提交
1982 1983 1984 1985 1986 1987 1988 1989
	if (res.type != RTN_UNICAST)
		goto martian_destination;

	err = ip_mkroute_input(skb, &res, &fl, in_dev, daddr, saddr, tos);
	if (err == -ENOBUFS)
		goto e_nobufs;
	if (err == -EINVAL)
		goto e_inval;
1990

L
Linus Torvalds 已提交
1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028
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;

	if (ZERONET(saddr))
		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;

	atomic_set(&rth->u.dst.__refcnt, 1);
	rth->u.dst.flags= DST_HOST;
	if (in_dev->cnf.no_policy)
		rth->u.dst.flags |= DST_NOPOLICY;
	rth->fl.fl4_dst	= daddr;
	rth->rt_dst	= daddr;
	rth->fl.fl4_tos	= tos;
2029
	rth->fl.mark    = skb->mark;
L
Linus Torvalds 已提交
2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040 2041 2042 2043 2044 2045 2046 2047 2048 2049
	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;
	rth->u.dst.dev	= &loopback_dev;
	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
2050
	hash = rt_hash(daddr, saddr, fl.iif);
L
Linus Torvalds 已提交
2051 2052 2053 2054 2055 2056 2057 2058 2059 2060 2061 2062 2063 2064 2065 2066 2067 2068 2069 2070
	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;
	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
2071 2072

e_hostunreach:
2073 2074
	err = -EHOSTUNREACH;
	goto done;
2075

L
Linus Torvalds 已提交
2076 2077 2078 2079 2080 2081 2082 2083 2084 2085 2086 2087 2088
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
2089
int ip_route_input(struct sk_buff *skb, __be32 daddr, __be32 saddr,
L
Linus Torvalds 已提交
2090 2091 2092 2093 2094 2095 2096
		   u8 tos, struct net_device *dev)
{
	struct rtable * rth;
	unsigned	hash;
	int iif = dev->ifindex;

	tos &= IPTOS_RT_MASK;
A
Al Viro 已提交
2097
	hash = rt_hash(daddr, saddr, iif);
L
Linus Torvalds 已提交
2098 2099 2100

	rcu_read_lock();
	for (rth = rcu_dereference(rt_hash_table[hash].chain); rth;
2101
	     rth = rcu_dereference(rth->u.dst.rt_next)) {
L
Linus Torvalds 已提交
2102 2103 2104 2105
		if (rth->fl.fl4_dst == daddr &&
		    rth->fl.fl4_src == saddr &&
		    rth->fl.iif == iif &&
		    rth->fl.oif == 0 &&
2106
		    rth->fl.mark == skb->mark &&
L
Linus Torvalds 已提交
2107 2108 2109 2110 2111 2112 2113 2114 2115 2116 2117 2118 2119 2120 2121 2122 2123 2124 2125 2126 2127 2128 2129 2130 2131 2132 2133 2134
		    rth->fl.fl4_tos == tos) {
			rth->u.dst.lastuse = jiffies;
			dst_hold(&rth->u.dst);
			rth->u.dst.__use++;
			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.
	 */
	if (MULTICAST(daddr)) {
		struct in_device *in_dev;

		rcu_read_lock();
2135
		if ((in_dev = __in_dev_get_rcu(dev)) != NULL) {
L
Linus Torvalds 已提交
2136
			int our = ip_check_mc(in_dev, daddr, saddr,
2137
				ip_hdr(skb)->protocol);
L
Linus Torvalds 已提交
2138 2139 2140 2141 2142 2143 2144 2145 2146 2147 2148 2149 2150 2151 2152 2153 2154
			if (our
#ifdef CONFIG_IP_MROUTE
			    || (!LOCAL_MCAST(daddr) && IN_DEV_MFORWARD(in_dev))
#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,
2155
				   struct fib_result* res,
L
Linus Torvalds 已提交
2156
				   const struct flowi *fl,
2157 2158 2159
				   const struct flowi *oldflp,
				   struct net_device *dev_out,
				   unsigned flags)
L
Linus Torvalds 已提交
2160 2161 2162 2163 2164 2165 2166 2167 2168
{
	struct rtable *rth;
	struct in_device *in_dev;
	u32 tos = RT_FL_TOS(oldflp);
	int err = 0;

	if (LOOPBACK(fl->fl4_src) && !(dev_out->flags&IFF_LOOPBACK))
		return -EINVAL;

2169
	if (fl->fl4_dst == htonl(0xFFFFFFFF))
L
Linus Torvalds 已提交
2170 2171 2172 2173 2174 2175 2176 2177 2178 2179 2180 2181 2182 2183 2184 2185 2186 2187 2188 2189 2190 2191
		res->type = RTN_BROADCAST;
	else if (MULTICAST(fl->fl4_dst))
		res->type = RTN_MULTICAST;
	else if (BADCLASS(fl->fl4_dst) || ZERONET(fl->fl4_dst))
		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;
2192
		if (!ip_check_mc(in_dev, oldflp->fl4_dst, oldflp->fl4_src,
L
Linus Torvalds 已提交
2193 2194 2195 2196 2197 2198 2199 2200 2201 2202 2203 2204 2205 2206 2207 2208 2209
				 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;
2210
	}
L
Linus Torvalds 已提交
2211

2212
	atomic_set(&rth->u.dst.__refcnt, 1);
L
Linus Torvalds 已提交
2213 2214 2215 2216 2217 2218 2219 2220 2221 2222 2223 2224 2225 2226 2227 2228 2229
	rth->u.dst.flags= DST_HOST;
#ifdef CONFIG_IP_ROUTE_MULTIPATH_CACHED
	if (res->fi) {
		rth->rt_multipath_alg = res->fi->fib_mp_alg;
		if (res->fi->fib_nhs > 1)
			rth->u.dst.flags |= DST_BALANCED;
	}
#endif
	if (in_dev->cnf.no_xfrm)
		rth->u.dst.flags |= DST_NOXFRM;
	if (in_dev->cnf.no_policy)
		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;
2230
	rth->fl.mark    = oldflp->mark;
L
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2231 2232 2233
	rth->rt_dst	= fl->fl4_dst;
	rth->rt_src	= fl->fl4_src;
	rth->rt_iif	= oldflp->oif ? : dev_out->ifindex;
2234
	/* get references to the devices that are to be hold by the routing
L
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2235 2236 2237 2238 2239 2240 2241 2242 2243 2244 2245 2246 2247 2248 2249 2250 2251
	   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;

	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;
2252
		if (flags & RTCF_LOCAL &&
L
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2253 2254 2255 2256 2257 2258 2259 2260 2261 2262 2263 2264 2265 2266 2267 2268 2269 2270 2271 2272 2273 2274 2275 2276 2277 2278 2279 2280 2281 2282 2283 2284 2285 2286
		    !(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) &&
			    !LOCAL_MCAST(oldflp->fl4_dst)) {
				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;
}

static inline int ip_mkroute_output_def(struct rtable **rp,
					struct fib_result* res,
					const struct flowi *fl,
					const struct flowi *oldflp,
					struct net_device *dev_out,
					unsigned flags)
{
C
Chuck Short 已提交
2287
	struct rtable *rth = NULL;
L
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2288 2289 2290
	int err = __mkroute_output(&rth, res, fl, oldflp, dev_out, flags);
	unsigned hash;
	if (err == 0) {
A
Al Viro 已提交
2291
		hash = rt_hash(oldflp->fl4_dst, oldflp->fl4_src, oldflp->oif);
L
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2292 2293
		err = rt_intern_hash(hash, rth, rp);
	}
2294

L
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	return err;
}

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)
{
#ifdef CONFIG_IP_ROUTE_MULTIPATH_CACHED
	unsigned char hop;
	unsigned hash;
	int err = -EINVAL;
C
Chuck Short 已提交
2309
	struct rtable *rth = NULL;
L
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2310 2311 2312 2313 2314 2315 2316 2317 2318 2319 2320 2321 2322

	if (res->fi && res->fi->fib_nhs > 1) {
		unsigned char hopcount = res->fi->fib_nhs;

		for (hop = 0; hop < hopcount; hop++) {
			struct net_device *dev2nexthop;

			res->nh_sel = hop;

			/* hold a work reference to the output device */
			dev2nexthop = FIB_RES_DEV(*res);
			dev_hold(dev2nexthop);

2323 2324 2325 2326
			/* put reference to previous result */
			if (hop)
				ip_rt_put(*rp);

L
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2327 2328 2329 2330 2331 2332
			err = __mkroute_output(&rth, res, fl, oldflp,
					       dev2nexthop, flags);

			if (err != 0)
				goto cleanup;

A
Al Viro 已提交
2333 2334
			hash = rt_hash(oldflp->fl4_dst, oldflp->fl4_src,
					oldflp->oif);
L
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			err = rt_intern_hash(hash, rth, rp);

			/* forward hop information to multipath impl. */
			multipath_set_nhinfo(rth,
					     FIB_RES_NETWORK(*res),
					     FIB_RES_NETMASK(*res),
					     res->prefixlen,
					     &FIB_RES_NH(*res));
		cleanup:
			/* release work reference to output device */
			dev_put(dev2nexthop);

			if (err != 0)
				return err;
		}
		return err;
	} else {
		return ip_mkroute_output_def(rp, res, fl, oldflp, dev_out,
					     flags);
	}
#else /* CONFIG_IP_ROUTE_MULTIPATH_CACHED */
	return ip_mkroute_output_def(rp, res, fl, oldflp, dev_out, flags);
#endif
}

/*
 * Major route resolver routine.
 */

static int ip_route_output_slow(struct rtable **rp, const struct flowi *oldflp)
{
	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),
				      } },
2375
			    .mark = oldflp->mark,
L
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2376 2377 2378 2379 2380 2381 2382 2383 2384 2385 2386 2387 2388 2389 2390 2391 2392 2393 2394 2395 2396 2397 2398
			    .iif = loopback_dev.ifindex,
			    .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;
		if (MULTICAST(oldflp->fl4_src) ||
		    BADCLASS(oldflp->fl4_src) ||
		    ZERONET(oldflp->fl4_src))
			goto out;

		/* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
		dev_out = ip_dev_find(oldflp->fl4_src);
2399
		if (dev_out == NULL)
L
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2400 2401 2402 2403 2404 2405 2406 2407 2408 2409
			goto out;

		/* I removed check for oif == dev_out->oif here.
		   It was wrong for two reasons:
		   1. ip_dev_find(saddr) can return wrong iface, if saddr is
		      assigned to multiple interfaces.
		   2. Moreover, we are allowed to send packets with saddr
		      of another iface. --ANK
		 */

2410
		if (oldflp->oif == 0
2411
		    && (MULTICAST(oldflp->fl4_dst) || oldflp->fl4_dst == htonl(0xFFFFFFFF))) {
L
Linus Torvalds 已提交
2412 2413 2414 2415 2416 2417 2418 2419 2420 2421 2422 2423 2424 2425 2426 2427 2428 2429 2430 2431 2432 2433 2434 2435 2436 2437 2438 2439 2440
			/* 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) {
		dev_out = dev_get_by_index(oldflp->oif);
		err = -ENODEV;
		if (dev_out == NULL)
			goto out;
2441 2442 2443

		/* RACE: Check return value of inet_select_addr instead. */
		if (__in_dev_get_rtnl(dev_out) == NULL) {
L
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2444 2445 2446 2447
			dev_put(dev_out);
			goto out;	/* Wrong error code */
		}

2448
		if (LOCAL_MCAST(oldflp->fl4_dst) || oldflp->fl4_dst == htonl(0xFFFFFFFF)) {
L
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2449 2450 2451 2452 2453 2454 2455 2456 2457 2458 2459 2460 2461 2462 2463 2464 2465 2466 2467 2468 2469 2470 2471 2472 2473 2474 2475 2476 2477 2478 2479 2480 2481 2482 2483 2484 2485 2486 2487 2488 2489 2490 2491 2492 2493 2494 2495 2496 2497 2498 2499 2500 2501 2502 2503 2504 2505 2506 2507 2508 2509 2510 2511 2512 2513 2514 2515 2516 2517 2518 2519 2520 2521 2522 2523 2524 2525 2526 2527 2528 2529 2530 2531 2532 2533 2534 2535 2536 2537 2538 2539 2540 2541 2542 2543 2544 2545 2546 2547 2548 2549 2550 2551 2552 2553 2554 2555 2556 2557 2558 2559 2560
			if (!fl.fl4_src)
				fl.fl4_src = inet_select_addr(dev_out, 0,
							      RT_SCOPE_LINK);
			goto make_route;
		}
		if (!fl.fl4_src) {
			if (MULTICAST(oldflp->fl4_dst))
				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);
		dev_out = &loopback_dev;
		dev_hold(dev_out);
		fl.oif = loopback_dev.ifindex;
		res.type = RTN_LOCAL;
		flags |= RTCF_LOCAL;
		goto make_route;
	}

	if (fib_lookup(&fl, &res)) {
		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);
		dev_out = &loopback_dev;
		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)
		fib_select_default(&fl, &res);

	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;
}

int __ip_route_output_key(struct rtable **rp, const struct flowi *flp)
{
	unsigned hash;
	struct rtable *rth;

A
Al Viro 已提交
2561
	hash = rt_hash(flp->fl4_dst, flp->fl4_src, flp->oif);
L
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2562 2563 2564

	rcu_read_lock_bh();
	for (rth = rcu_dereference(rt_hash_table[hash].chain); rth;
2565
		rth = rcu_dereference(rth->u.dst.rt_next)) {
L
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2566 2567 2568 2569
		if (rth->fl.fl4_dst == flp->fl4_dst &&
		    rth->fl.fl4_src == flp->fl4_src &&
		    rth->fl.iif == 0 &&
		    rth->fl.oif == flp->oif &&
2570
		    rth->fl.mark == flp->mark &&
L
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2571 2572 2573 2574 2575 2576 2577 2578 2579 2580 2581 2582 2583 2584 2585 2586 2587 2588 2589 2590 2591 2592 2593 2594 2595 2596 2597 2598
		    !((rth->fl.fl4_tos ^ flp->fl4_tos) &
			    (IPTOS_RT_MASK | RTO_ONLINK))) {

			/* check for multipath routes and choose one if
			 * necessary
			 */
			if (multipath_select_route(flp, rth, rp)) {
				dst_hold(&(*rp)->u.dst);
				RT_CACHE_STAT_INC(out_hit);
				rcu_read_unlock_bh();
				return 0;
			}

			rth->u.dst.lastuse = jiffies;
			dst_hold(&rth->u.dst);
			rth->u.dst.__use++;
			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();

	return ip_route_output_slow(rp, flp);
}

2599 2600
EXPORT_SYMBOL_GPL(__ip_route_output_key);

L
Linus Torvalds 已提交
2601 2602 2603 2604 2605 2606 2607 2608 2609 2610 2611 2612 2613 2614 2615 2616 2617 2618
int ip_route_output_flow(struct rtable **rp, struct flowi *flp, struct sock *sk, int flags)
{
	int err;

	if ((err = __ip_route_output_key(rp, flp)) != 0)
		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;
		return xfrm_lookup((struct dst_entry **)rp, flp, sk, flags);
	}

	return 0;
}

2619 2620
EXPORT_SYMBOL_GPL(ip_route_output_flow);

L
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2621 2622 2623 2624 2625 2626
int ip_route_output_key(struct rtable **rp, struct flowi *flp)
{
	return ip_route_output_flow(rp, flp, NULL, 0);
}

static int rt_fill_info(struct sk_buff *skb, u32 pid, u32 seq, int event,
2627
			int nowait, unsigned int flags)
L
Linus Torvalds 已提交
2628 2629 2630
{
	struct rtable *rt = (struct rtable*)skb->dst;
	struct rtmsg *r;
2631
	struct nlmsghdr *nlh;
2632 2633
	long expires;
	u32 id = 0, ts = 0, tsage = 0, error;
2634 2635 2636

	nlh = nlmsg_put(skb, pid, seq, event, sizeof(*r), flags);
	if (nlh == NULL)
2637
		return -EMSGSIZE;
2638 2639

	r = nlmsg_data(nlh);
L
Linus Torvalds 已提交
2640 2641 2642 2643 2644
	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;
2645
	NLA_PUT_U32(skb, RTA_TABLE, RT_TABLE_MAIN);
L
Linus Torvalds 已提交
2646 2647 2648 2649 2650 2651
	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;
2652

2653
	NLA_PUT_BE32(skb, RTA_DST, rt->rt_dst);
2654

L
Linus Torvalds 已提交
2655 2656
	if (rt->fl.fl4_src) {
		r->rtm_src_len = 32;
2657
		NLA_PUT_BE32(skb, RTA_SRC, rt->fl.fl4_src);
L
Linus Torvalds 已提交
2658 2659
	}
	if (rt->u.dst.dev)
2660
		NLA_PUT_U32(skb, RTA_OIF, rt->u.dst.dev->ifindex);
L
Linus Torvalds 已提交
2661 2662
#ifdef CONFIG_NET_CLS_ROUTE
	if (rt->u.dst.tclassid)
2663
		NLA_PUT_U32(skb, RTA_FLOW, rt->u.dst.tclassid);
L
Linus Torvalds 已提交
2664 2665
#endif
#ifdef CONFIG_IP_ROUTE_MULTIPATH_CACHED
2666 2667
	if (rt->rt_multipath_alg != IP_MP_ALG_NONE)
		NLA_PUT_U32(skb, RTA_MP_ALGO, rt->rt_multipath_alg);
L
Linus Torvalds 已提交
2668 2669
#endif
	if (rt->fl.iif)
2670
		NLA_PUT_BE32(skb, RTA_PREFSRC, rt->rt_spec_dst);
L
Linus Torvalds 已提交
2671
	else if (rt->rt_src != rt->fl.fl4_src)
2672
		NLA_PUT_BE32(skb, RTA_PREFSRC, rt->rt_src);
2673

L
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2674
	if (rt->rt_dst != rt->rt_gateway)
2675
		NLA_PUT_BE32(skb, RTA_GATEWAY, rt->rt_gateway);
2676

L
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2677
	if (rtnetlink_put_metrics(skb, rt->u.dst.metrics) < 0)
2678 2679
		goto nla_put_failure;

2680 2681
	error = rt->u.dst.error;
	expires = rt->u.dst.expires ? rt->u.dst.expires - jiffies : 0;
L
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2682
	if (rt->peer) {
2683
		id = rt->peer->ip_id_count;
L
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2684
		if (rt->peer->tcp_ts_stamp) {
2685
			ts = rt->peer->tcp_ts;
2686
			tsage = get_seconds() - rt->peer->tcp_ts_stamp;
L
Linus Torvalds 已提交
2687 2688
		}
	}
2689

L
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2690 2691
	if (rt->fl.iif) {
#ifdef CONFIG_IP_MROUTE
2692
		__be32 dst = rt->rt_dst;
L
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2693 2694 2695 2696 2697 2698 2699 2700

		if (MULTICAST(dst) && !LOCAL_MCAST(dst) &&
		    ipv4_devconf.mc_forwarding) {
			int err = ipmr_get_route(skb, r, nowait);
			if (err <= 0) {
				if (!nowait) {
					if (err == 0)
						return 0;
2701
					goto nla_put_failure;
L
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2702 2703
				} else {
					if (err == -EMSGSIZE)
2704
						goto nla_put_failure;
2705
					error = err;
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2706 2707 2708 2709
				}
			}
		} else
#endif
2710
			NLA_PUT_U32(skb, RTA_IIF, rt->fl.iif);
L
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2711 2712
	}

2713 2714 2715
	if (rtnl_put_cacheinfo(skb, &rt->u.dst, id, ts, tsage,
			       expires, error) < 0)
		goto nla_put_failure;
2716 2717

	return nlmsg_end(skb, nlh);
L
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2718

2719
nla_put_failure:
2720 2721
	nlmsg_cancel(skb, nlh);
	return -EMSGSIZE;
L
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2722 2723
}

2724
static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr* nlh, void *arg)
L
Linus Torvalds 已提交
2725
{
2726 2727
	struct rtmsg *rtm;
	struct nlattr *tb[RTA_MAX+1];
L
Linus Torvalds 已提交
2728
	struct rtable *rt = NULL;
A
Al Viro 已提交
2729 2730 2731
	__be32 dst = 0;
	__be32 src = 0;
	u32 iif;
2732
	int err;
L
Linus Torvalds 已提交
2733 2734
	struct sk_buff *skb;

2735 2736 2737 2738 2739 2740
	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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2741
	skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
2742 2743 2744 2745
	if (skb == NULL) {
		err = -ENOBUFS;
		goto errout;
	}
L
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2746 2747 2748 2749

	/* Reserve room for dummy headers, this skb can pass
	   through good chunk of routing engine.
	 */
2750
	skb_reset_mac_header(skb);
2751
	skb_reset_network_header(skb);
2752 2753

	/* Bugfix: need to give ip_route_input enough of an IP header to not gag. */
2754
	ip_hdr(skb)->protocol = IPPROTO_ICMP;
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	skb_reserve(skb, MAX_HEADER + sizeof(struct iphdr));

2757 2758
	src = tb[RTA_SRC] ? nla_get_be32(tb[RTA_SRC]) : 0;
	dst = tb[RTA_DST] ? nla_get_be32(tb[RTA_DST]) : 0;
2759
	iif = tb[RTA_IIF] ? nla_get_u32(tb[RTA_IIF]) : 0;
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	if (iif) {
2762 2763 2764 2765 2766 2767 2768 2769
		struct net_device *dev;

		dev = __dev_get_by_index(iif);
		if (dev == NULL) {
			err = -ENODEV;
			goto errout_free;
		}

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		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();
2775 2776 2777

		rt = (struct rtable*) skb->dst;
		if (err == 0 && rt->u.dst.error)
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			err = -rt->u.dst.error;
	} else {
2780 2781 2782 2783 2784 2785 2786 2787 2788 2789
		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,
		};
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		err = ip_route_output_key(&rt, &fl);
	}
2792

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	if (err)
2794
		goto errout_free;
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	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,
2801
				RTM_NEWROUTE, 0, 0);
2802 2803
	if (err <= 0)
		goto errout_free;
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2805
	err = rtnl_unicast(skb, NETLINK_CB(in_skb).pid);
2806
errout:
2807
	return err;
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2808

2809
errout_free:
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	kfree_skb(skb);
2811
	goto errout;
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}

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];
	s_idx = idx = cb->args[1];
	for (h = 0; h <= rt_hash_mask; h++) {
		if (h < s_h) continue;
		if (h > s_h)
			s_idx = 0;
		rcu_read_lock_bh();
		for (rt = rcu_dereference(rt_hash_table[h].chain), idx = 0; rt;
2828
		     rt = rcu_dereference(rt->u.dst.rt_next), idx++) {
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			if (idx < s_idx)
				continue;
			skb->dst = dst_clone(&rt->u.dst);
			if (rt_fill_info(skb, NETLINK_CB(cb->skb).pid,
2833
					 cb->nlh->nlmsg_seq, RTM_NEWROUTE,
2834
					 1, NLM_F_MULTI) <= 0) {
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				dst_release(xchg(&skb->dst, NULL));
				rcu_read_unlock_bh();
				goto done;
			}
			dst_release(xchg(&skb->dst, NULL));
		}
		rcu_read_unlock_bh();
	}

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;
2866
	}
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	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,
2877
						size_t newlen)
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{
	int delay;
	if (newlen != sizeof(int))
		return -EINVAL;
	if (get_user(delay, (int __user *)newval))
2883 2884
		return -EFAULT;
	rt_cache_flush(delay);
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	return 0;
}

ctl_table ipv4_route_table[] = {
2889
	{
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		.ctl_name 	= NET_IPV4_ROUTE_FLUSH,
		.procname	= "flush",
		.data		= &flush_delay,
		.maxlen		= sizeof(int),
2894
		.mode		= 0200,
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		.proc_handler	= &ipv4_sysctl_rtcache_flush,
		.strategy	= &ipv4_sysctl_rtcache_flush_strategy,
	},
	{
		.ctl_name	= NET_IPV4_ROUTE_MIN_DELAY,
		.procname	= "min_delay",
		.data		= &ip_rt_min_delay,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec_jiffies,
		.strategy	= &sysctl_jiffies,
	},
	{
		.ctl_name	= NET_IPV4_ROUTE_MAX_DELAY,
		.procname	= "max_delay",
		.data		= &ip_rt_max_delay,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec_jiffies,
		.strategy	= &sysctl_jiffies,
	},
	{
		.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 */
2934

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		.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
struct ip_rt_acct *ip_rt_acct;

/* This code sucks.  But you should have seen it before! --RR */

/* IP route accounting ptr for this logical cpu number. */
#define IP_RT_ACCT_CPU(i) (ip_rt_acct + i * 256)

#ifdef CONFIG_PROC_FS
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 *src = ((u32 *) IP_RT_ACCT_CPU(0)) + offset;
		u32 *dst = (u32 *) buffer;

		/* Copy first cpu. */
		*start = buffer;
		memcpy(dst, src, length);

		/* Add the other cpus in, one int at a time */
3094
		for_each_possible_cpu(i) {
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Linus Torvalds 已提交
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			unsigned int j;

			src = ((u32 *) IP_RT_ACCT_CPU(i)) + offset;

			for (j = 0; j < length/4; j++)
				dst[j] += src[j];
		}
	}
	return length;
}
#endif /* CONFIG_PROC_FS */
#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)
{
3120
	int rc = 0;
L
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3121 3122 3123 3124 3125

	rt_hash_rnd = (int) ((num_physpages ^ (num_physpages>>8)) ^
			     (jiffies ^ (jiffies >> 7)));

#ifdef CONFIG_NET_CLS_ROUTE
3126 3127
	{
	int order;
L
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3128 3129 3130 3131 3132 3133 3134
	for (order = 0;
	     (PAGE_SIZE << order) < 256 * sizeof(struct ip_rt_acct) * NR_CPUS; order++)
		/* NOTHING */;
	ip_rt_acct = (struct ip_rt_acct *)__get_free_pages(GFP_KERNEL, order);
	if (!ip_rt_acct)
		panic("IP: failed to allocate ip_rt_acct\n");
	memset(ip_rt_acct, 0, PAGE_SIZE << order);
3135
	}
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3136 3137
#endif

A
Alexey Dobriyan 已提交
3138 3139 3140
	ipv4_dst_ops.kmem_cachep =
		kmem_cache_create("ip_dst_cache", sizeof(struct rtable), 0,
				  SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL);
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Linus Torvalds 已提交
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3142 3143 3144 3145 3146
	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) ?
3147
					15 : 17,
3148
					0,
3149 3150 3151
					&rt_hash_log,
					&rt_hash_mask,
					0);
3152 3153
	memset(rt_hash_table, 0, (rt_hash_mask + 1) * sizeof(struct rt_hash_bucket));
	rt_hash_lock_init();
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3154 3155 3156 3157 3158 3159 3160 3161 3162 3163 3164 3165 3166 3167 3168 3169 3170 3171 3172 3173 3174 3175 3176 3177 3178 3179 3180 3181 3182

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

	devinet_init();
	ip_fib_init();

	init_timer(&rt_flush_timer);
	rt_flush_timer.function = rt_run_flush;
	init_timer(&rt_periodic_timer);
	rt_periodic_timer.function = rt_check_expire;
	init_timer(&rt_secret_timer);
	rt_secret_timer.function = rt_secret_rebuild;

	/* All the timers, started at system startup tend
	   to synchronize. Perturb it a bit.
	 */
	rt_periodic_timer.expires = jiffies + net_random() % ip_rt_gc_interval +
					ip_rt_gc_interval;
	add_timer(&rt_periodic_timer);

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

#ifdef CONFIG_PROC_FS
	{
	struct proc_dir_entry *rtstat_pde = NULL; /* keep gcc happy */
	if (!proc_net_fops_create("rt_cache", S_IRUGO, &rt_cache_seq_fops) ||
3183 3184
	    !(rtstat_pde = create_proc_entry("rt_cache", S_IRUGO,
					     proc_net_stat))) {
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		return -ENOMEM;
	}
	rtstat_pde->proc_fops = &rt_cpu_seq_fops;
	}
#ifdef CONFIG_NET_CLS_ROUTE
	create_proc_read_entry("rt_acct", 0, proc_net, ip_rt_acct_read, NULL);
#endif
#endif
#ifdef CONFIG_XFRM
	xfrm_init();
	xfrm4_init();
#endif
3197 3198
	rtnl_register(PF_INET, RTM_GETROUTE, inet_rtm_getroute, NULL);

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	return rc;
}

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