route.c 74.9 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>
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#include <linux/workqueue.h>
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#include <linux/skbuff.h>
#include <linux/inetdevice.h>
#include <linux/igmp.h>
#include <linux/pkt_sched.h>
#include <linux/mroute.h>
#include <linux/netfilter_ipv4.h>
#include <linux/random.h>
#include <linux/jhash.h>
#include <linux/rcupdate.h>
#include <linux/times.h>
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#include <net/dst.h>
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#include <net/net_namespace.h>
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#include <net/protocol.h>
#include <net/ip.h>
#include <net/route.h>
#include <net/inetpeer.h>
#include <net/sock.h>
#include <net/ip_fib.h>
#include <net/arp.h>
#include <net/tcp.h>
#include <net/icmp.h>
#include <net/xfrm.h>
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#include <net/netevent.h>
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#include <net/rtnetlink.h>
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#ifdef CONFIG_SYSCTL
#include <linux/sysctl.h>
#endif

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

#define IP_MAX_MTU	0xFFF0

#define RT_GC_TIMEOUT (300*HZ)

static int ip_rt_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;
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static int ip_rt_flush_expected;
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static unsigned long rt_deadline;

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

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

/*
 *	Interface to generic destination cache.
 */

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

#define ECN_OR_COST(class)	TC_PRIO_##class

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


/*
 * Route cache.
 */

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

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

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

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

	for (i = 0; i < RT_HASH_LOCK_SZ; i++)
		spin_lock_init(&rt_hash_locks[i]);
}
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#else
# define rt_hash_lock_addr(slot) NULL
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static inline void rt_hash_lock_init(void)
{
}
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#endif
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static struct rt_hash_bucket 	*rt_hash_table;
static unsigned			rt_hash_mask;
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static unsigned int		rt_hash_log;
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static 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();
	}
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	return rcu_dereference(r);
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}

static struct rtable *rt_cache_get_next(struct seq_file *seq, struct rtable *r)
{
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	struct rt_cache_iter_state *st = 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;
	}
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	return rcu_dereference(r);
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}

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)
{
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	return seq_open_private(file, &rt_cache_seq_ops,
			sizeof(struct rt_cache_iter_state));
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}

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


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

	if (*pos == 0)
		return SEQ_START_TOKEN;

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

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

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

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

}

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

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

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

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


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

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

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

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

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

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

	offset /= sizeof(u32);

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

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

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

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

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

	pde = create_proc_entry("rt_cache", S_IRUGO, net->proc_net_stat);
	if (!pde)
		goto err2;

	pde->proc_fops = &rt_cpu_seq_fops;

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

#ifdef CONFIG_NET_CLS_ROUTE
err3:
	remove_proc_entry("rt_cache", net->proc_net_stat);
#endif
err2:
	remove_proc_entry("rt_cache", net->proc_net);
err1:
	return -ENOMEM;
}
#else
static inline int ip_rt_proc_init(struct net *net)
{
	return 0;
}
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#endif /* CONFIG_PROC_FS */
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static __inline__ void rt_free(struct rtable *rt)
{
	call_rcu_bh(&rt->u.dst.rcu_head, dst_rcu_free);
}

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

static __inline__ int rt_fast_clean(struct rtable *rth)
{
	/* Kill broadcast/multicast entries very aggresively, if they
	   collide in hash table with more useful entries */
	return (rth->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST)) &&
588
		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)
{
642 643
	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)) |
644
		(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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}

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/*
 * Perform a full scan of hash table and free all entries.
 * Can be called by a softirq or a process.
 * In the later case, we want to be reschedule if necessary
 */
static void rt_do_flush(int process_context)
{
	unsigned int i;
	struct rtable *rth, *next;

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

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

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

static void rt_check_expire(void)
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{
682 683
	static unsigned int rover;
	unsigned int i = rover, goal;
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	struct rtable *rth, **rthp;
685 686 687 688 689 690
	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;
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	if (goal > rt_hash_mask)
		goal = rt_hash_mask + 1;
693
	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;

699 700 701
		if (need_resched())
			cond_resched();

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		if (*rthp == NULL)
703
			continue;
704
		spin_lock_bh(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 */
708
				if (time_before_eq(jiffies, rth->u.dst.expires)) {
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					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. */
720
			*rthp = rth->u.dst.rt_next;
721
			rt_free(rth);
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		}
723
		spin_unlock_bh(rt_hash_lock_addr(i));
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	}
	rover = i;
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}

/*
 * rt_worker_func() is run in process context.
 * If a whole flush was scheduled, it is done.
 * Else, we call rt_check_expire() to scan part of the hash table
 */
static void rt_worker_func(struct work_struct *work)
{
	if (ip_rt_flush_expected) {
		ip_rt_flush_expected = 0;
		rt_do_flush(1);
	} else
		rt_check_expire();
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	schedule_delayed_work(&expires_work, 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.
 */
746
static void rt_run_flush(unsigned long process_context)
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{
	rt_deadline = 0;

	get_random_bytes(&rt_hash_rnd, 4);

752
	rt_do_flush(process_context);
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}

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;

	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);
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		rt_run_flush(user_mode);
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		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);
}

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/*
 * We change rt_hash_rnd and ask next rt_worker_func() invocation
 * to perform a flush in process context
 */
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static void rt_secret_rebuild(unsigned long dummy)
{
803 804 805 806 807
	get_random_bytes(&rt_hash_rnd, 4);
	ip_rt_flush_expected = 1;
	cancel_delayed_work(&expires_work);
	schedule_delayed_work(&expires_work, HZ/10);
	mod_timer(&rt_secret_timer, jiffies + ip_rt_secret_interval);
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}

/*
   Short description of GC goals.

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

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

823
static int rt_garbage_collect(struct dst_ops *ops)
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{
	static unsigned long expire = RT_GC_TIMEOUT;
	static unsigned long last_gc;
	static int rover;
	static int equilibrium;
	struct rtable *rth, **rthp;
	unsigned long now = jiffies;
	int goal;

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

	RT_CACHE_STAT_INC(gc_total);

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

	/* Calculate number of entries, which we want to expire now. */
	goal = atomic_read(&ipv4_dst_ops.entries) -
		(ip_rt_gc_elasticity << rt_hash_log);
	if (goal <= 0) {
		if (equilibrium < ipv4_dst_ops.gc_thresh)
			equilibrium = ipv4_dst_ops.gc_thresh;
		goal = atomic_read(&ipv4_dst_ops.entries) - equilibrium;
		if (goal > 0) {
854
			equilibrium += min_t(unsigned int, goal >> 1, rt_hash_mask + 1);
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			goal = atomic_read(&ipv4_dst_ops.entries) - equilibrium;
		}
	} else {
		/* We are in dangerous area. Try to reduce cache really
		 * aggressively.
		 */
861
		goal = max_t(unsigned int, goal >> 1, rt_hash_mask + 1);
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		equilibrium = atomic_read(&ipv4_dst_ops.entries) - goal;
	}

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

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

	do {
		int i, k;

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

			k = (k + 1) & rt_hash_mask;
			rthp = &rt_hash_table[k].chain;
881
			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;
885
					rthp = &rth->u.dst.rt_next;
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					continue;
				}
888
				*rthp = rth->u.dst.rt_next;
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				rt_free(rth);
				goal--;
			}
892
			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;

962
	spin_lock_bh(rt_hash_lock_addr(hash));
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	while ((rth = *rthp) != NULL) {
		if (compare_keys(&rth->fl, &rt->fl)) {
			/* Put it first */
966
			*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.
			 */
972
			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);

980
			dst_use(&rth->u.dst, now);
981
			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++;

1000
		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) {
1011
			*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) {
1022
			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;
1038
				rt_garbage_collect(&ipv4_dst_ops);
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				ip_rt_gc_min_interval	= saved_int;
				ip_rt_gc_elasticity	= saved_elasticity;
				goto restart;
			}

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

1051
	rt->u.dst.rt_next = rt_hash_table[hash].chain;
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#if RT_CACHE_DEBUG >= 2
1053
	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));
1057
		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;
1063
	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);
1099
	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
1121
		printk(KERN_DEBUG "rt_bind_peer(0) @%p\n",
1122
		       __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;

1131
	spin_lock_bh(rt_hash_lock_addr(hash));
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	ip_rt_put(rt);
	for (rthp = &rt_hash_table[hash].chain; *rthp;
1134
	     rthp = &(*rthp)->u.dst.rt_next)
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		if (*rthp == rt) {
1136
			*rthp = rt->u.dst.rt_next;
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			rt_free(rt);
			break;
		}
1140
	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 };
1151
	struct netevent_redirect netevent;
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	if (!in_dev)
		return;

	if (new_gw == old_gw || !IN_DEV_RX_REDIRECTS(in_dev)
1157
	    || ipv4_is_multicast(new_gw) || ipv4_is_lbcast(new_gw)
1158
	    || ipv4_is_zeronet(new_gw))
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		goto reject_redirect;

	if (!IN_DEV_SHARED_MEDIA(in_dev)) {
		if (!inet_addr_onlink(in_dev, new_gw, old_gw))
			goto reject_redirect;
		if (IN_DEV_SEC_REDIRECTS(in_dev) && ip_fib_check_default(new_gw, dev))
			goto reject_redirect;
	} else {
1167
		if (inet_addr_type(&init_net, new_gw) != RTN_UNICAST)
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			goto reject_redirect;
	}

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

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

				if (rth->fl.fl4_dst != daddr ||
				    rth->fl.fl4_src != skeys[i] ||
				    rth->fl.oif != ikeys[k] ||
				    rth->fl.iif != 0) {
1185
					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;
1208
				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;
				}
1243

1244 1245
				netevent.old = &rth->u.dst;
				netevent.new = &rt->u.dst;
1246 1247
				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"
1267
			"  Advised path = %u.%u.%u.%u -> %u.%u.%u.%u\n",
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		       NIPQUAD(old_gw), dev->name, NIPQUAD(new_gw),
1269
		       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
1288
			printk(KERN_DEBUG "ipv4_negative_advice: redirect to "
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					  "%u.%u.%u.%u/%02x dropped\n",
				NIPQUAD(rt->rt_dst), rt->fl.fl4_tos);
#endif
			rt_del(hash, rt);
			ret = NULL;
		}
	}
	return ret;
}

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

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

	if (!in_dev)
		return;

	if (!IN_DEV_TX_REDIRECTS(in_dev))
		goto out;

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

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

	/* Check for load limit; set rate_last to the latest sent
	 * redirect.
	 */
1343 1344
	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:
1361
	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;
1379
			IP_INC_STATS_BH(IPSTATS_MIB_INNOROUTES);
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			break;
		case EACCES:
			code = ICMP_PKT_FILTERED;
			break;
	}

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

out:	kfree_skb(skb);
	return 0;
1398
}
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/*
 *	The last two values are not from the RFC but
 *	are needed for AMPRnet AX.25 paths.
 */

1405
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;
1411

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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;
1423 1424
	__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;
1435
		     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]) {
1455
					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);
1485
		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;
1516 1517 1518
	if (dev != dev->nd_net->loopback_dev && idev && idev->dev == dev) {
		struct in_device *loopback_idev =
			in_dev_get(dev->nd_net->loopback_dev);
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		if (loopback_idev) {
			rt->idev = loopback_idev;
			in_dev_put(idev);
		}
	}
}

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

	icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0);

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

static int ip_rt_bug(struct sk_buff *skb)
{
	printk(KERN_DEBUG "ip_rt_bug: %u.%u.%u.%u -> %u.%u.%u.%u, %s\n",
1540
		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;
1562
	else if (fib_lookup(rt->u.dst.dev->nd_net, &rt->fl, &res) == 0) {
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		src = FIB_RES_PREFSRC(res);
		fib_res_put(&res);
	} else
		src = inet_select_addr(rt->u.dst.dev, rt->rt_gateway,
					RT_SCOPE_UNIVERSE);
	memcpy(addr, &src, 4);
}

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

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

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

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

#ifdef CONFIG_NET_CLS_ROUTE
#ifdef CONFIG_IP_MULTIPLE_TABLES
	set_class_tag(rt, fib_rules_tclass(res));
#endif
	set_class_tag(rt, itag);
#endif
1620
	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;

1637
	if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) ||
1638
	    ipv4_is_loopback(saddr) || skb->protocol != htons(ETH_P_IP))
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		goto e_inval;

1641 1642
	if (ipv4_is_zeronet(saddr)) {
		if (!ipv4_is_local_multicast(daddr))
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			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;
1657
	if (IN_DEV_CONF_GET(in_dev, NOPOLICY))
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		rth->u.dst.flags |= DST_NOPOLICY;
	rth->fl.fl4_dst	= daddr;
	rth->rt_dst	= daddr;
	rth->fl.fl4_tos	= tos;
1662
	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;
1670
	rth->u.dst.dev	= init_net.loopback_dev;
L
Linus Torvalds 已提交
1671 1672 1673 1674 1675 1676 1677 1678 1679 1680 1681 1682 1683
	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
1684
	if (!ipv4_is_local_multicast(daddr) && IN_DEV_MFORWARD(in_dev))
L
Linus Torvalds 已提交
1685 1686 1687 1688 1689
		rth->u.dst.input = ip_mr_input;
#endif
	RT_CACHE_STAT_INC(in_slow_mc);

	in_dev_put(in_dev);
A
Al Viro 已提交
1690
	hash = rt_hash(daddr, saddr, dev->ifindex);
L
Linus Torvalds 已提交
1691 1692 1693 1694 1695 1696 1697 1698 1699 1700 1701 1702 1703 1704 1705
	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
1706 1707
				     __be32 daddr,
				     __be32 saddr)
L
Linus Torvalds 已提交
1708 1709 1710 1711 1712 1713 1714 1715 1716 1717 1718
{
	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);
1719
		if (dev->hard_header_len && skb_mac_header_was_set(skb)) {
L
Linus Torvalds 已提交
1720
			int i;
1721
			const unsigned char *p = skb_mac_header(skb);
L
Linus Torvalds 已提交
1722 1723 1724 1725 1726 1727 1728 1729 1730 1731 1732 1733
			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
}

1734 1735 1736
static inline int __mkroute_input(struct sk_buff *skb,
				  struct fib_result* res,
				  struct in_device *in_dev,
A
Al Viro 已提交
1737
				  __be32 daddr, __be32 saddr, u32 tos,
1738
				  struct rtable **result)
L
Linus Torvalds 已提交
1739 1740 1741 1742 1743 1744
{

	struct rtable *rth;
	int err;
	struct in_device *out_dev;
	unsigned flags = 0;
1745 1746
	__be32 spec_dst;
	u32 itag;
L
Linus Torvalds 已提交
1747 1748 1749 1750 1751 1752 1753 1754 1755 1756 1757

	/* 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;
	}


1758
	err = fib_validate_source(saddr, daddr, tos, FIB_RES_OIF(*res),
L
Linus Torvalds 已提交
1759 1760
				  in_dev->dev, &spec_dst, &itag);
	if (err < 0) {
1761
		ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr,
L
Linus Torvalds 已提交
1762
					 saddr);
1763

L
Linus Torvalds 已提交
1764 1765 1766 1767 1768 1769 1770
		err = -EINVAL;
		goto cleanup;
	}

	if (err)
		flags |= RTCF_DIRECTSRC;

1771
	if (out_dev == in_dev && err && !(flags & RTCF_MASQ) &&
L
Linus Torvalds 已提交
1772 1773 1774 1775 1776 1777 1778 1779
	    (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.
		 */
1780
		if (out_dev == in_dev) {
L
Linus Torvalds 已提交
1781 1782 1783 1784 1785 1786 1787 1788 1789 1790 1791 1792
			err = -EINVAL;
			goto cleanup;
		}
	}


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

1793
	atomic_set(&rth->u.dst.__refcnt, 1);
L
Linus Torvalds 已提交
1794
	rth->u.dst.flags= DST_HOST;
1795
	if (IN_DEV_CONF_GET(in_dev, NOPOLICY))
L
Linus Torvalds 已提交
1796
		rth->u.dst.flags |= DST_NOPOLICY;
1797
	if (IN_DEV_CONF_GET(out_dev, NOXFRM))
L
Linus Torvalds 已提交
1798 1799 1800 1801
		rth->u.dst.flags |= DST_NOXFRM;
	rth->fl.fl4_dst	= daddr;
	rth->rt_dst	= daddr;
	rth->fl.fl4_tos	= tos;
1802
	rth->fl.mark    = skb->mark;
L
Linus Torvalds 已提交
1803 1804 1805 1806 1807 1808 1809 1810 1811 1812 1813 1814 1815 1816 1817 1818 1819 1820 1821 1822 1823 1824 1825 1826
	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;
1827
}
L
Linus Torvalds 已提交
1828

1829 1830 1831 1832 1833
static inline int ip_mkroute_input(struct sk_buff *skb,
				   struct fib_result* res,
				   const struct flowi *fl,
				   struct in_device *in_dev,
				   __be32 daddr, __be32 saddr, u32 tos)
L
Linus Torvalds 已提交
1834
{
C
Chuck Short 已提交
1835
	struct rtable* rth = NULL;
L
Linus Torvalds 已提交
1836 1837 1838 1839 1840 1841 1842 1843 1844 1845 1846 1847 1848 1849
	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
1850
	hash = rt_hash(daddr, saddr, fl->iif);
1851
	return rt_intern_hash(hash, rth, (struct rtable**)&skb->dst);
L
Linus Torvalds 已提交
1852 1853 1854 1855 1856 1857 1858 1859 1860 1861 1862 1863
}

/*
 *	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
1864
static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
L
Linus Torvalds 已提交
1865 1866 1867 1868 1869 1870 1871 1872 1873 1874
			       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,
				      } },
1875
			    .mark = skb->mark,
L
Linus Torvalds 已提交
1876 1877 1878 1879 1880
			    .iif = dev->ifindex };
	unsigned	flags = 0;
	u32		itag = 0;
	struct rtable * rth;
	unsigned	hash;
A
Al Viro 已提交
1881
	__be32		spec_dst;
L
Linus Torvalds 已提交
1882 1883
	int		err = -EINVAL;
	int		free_res = 0;
1884
	struct net    * net = dev->nd_net;
L
Linus Torvalds 已提交
1885 1886 1887 1888 1889 1890 1891 1892 1893 1894

	/* 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.
	 */

1895
	if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) ||
1896
	    ipv4_is_loopback(saddr))
L
Linus Torvalds 已提交
1897 1898
		goto martian_source;

1899
	if (daddr == htonl(0xFFFFFFFF) || (saddr == 0 && daddr == 0))
L
Linus Torvalds 已提交
1900 1901 1902 1903 1904
		goto brd_input;

	/* Accept zero addresses only to limited broadcast;
	 * I even do not know to fix it or not. Waiting for complains :-)
	 */
1905
	if (ipv4_is_zeronet(saddr))
L
Linus Torvalds 已提交
1906 1907
		goto martian_source;

1908
	if (ipv4_is_lbcast(daddr) || ipv4_is_zeronet(daddr) ||
1909
	    ipv4_is_loopback(daddr))
L
Linus Torvalds 已提交
1910 1911 1912 1913 1914
		goto martian_destination;

	/*
	 *	Now we are ready to route packet.
	 */
1915
	if ((err = fib_lookup(net, &fl, &res)) != 0) {
L
Linus Torvalds 已提交
1916
		if (!IN_DEV_FORWARD(in_dev))
1917
			goto e_hostunreach;
L
Linus Torvalds 已提交
1918 1919 1920 1921 1922 1923 1924 1925 1926 1927 1928 1929
		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,
1930
					     net->loopback_dev->ifindex,
L
Linus Torvalds 已提交
1931 1932 1933 1934 1935 1936 1937 1938 1939 1940
					     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))
1941
		goto e_hostunreach;
L
Linus Torvalds 已提交
1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 1954 1955
	if (res.type != RTN_UNICAST)
		goto martian_destination;

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

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

1956
	if (ipv4_is_zeronet(saddr))
L
Linus Torvalds 已提交
1957 1958 1959 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978
		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;
1979
	if (IN_DEV_CONF_GET(in_dev, NOPOLICY))
L
Linus Torvalds 已提交
1980 1981 1982 1983
		rth->u.dst.flags |= DST_NOPOLICY;
	rth->fl.fl4_dst	= daddr;
	rth->rt_dst	= daddr;
	rth->fl.fl4_tos	= tos;
1984
	rth->fl.mark    = skb->mark;
L
Linus Torvalds 已提交
1985 1986 1987 1988 1989 1990 1991
	rth->fl.fl4_src	= saddr;
	rth->rt_src	= saddr;
#ifdef CONFIG_NET_CLS_ROUTE
	rth->u.dst.tclassid = itag;
#endif
	rth->rt_iif	=
	rth->fl.iif	= dev->ifindex;
1992
	rth->u.dst.dev	= net->loopback_dev;
L
Linus Torvalds 已提交
1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004
	dev_hold(rth->u.dst.dev);
	rth->idev	= in_dev_get(rth->u.dst.dev);
	rth->rt_gateway	= daddr;
	rth->rt_spec_dst= spec_dst;
	rth->u.dst.input= ip_local_deliver;
	rth->rt_flags 	= flags|RTCF_LOCAL;
	if (res.type == RTN_UNREACHABLE) {
		rth->u.dst.input= ip_error;
		rth->u.dst.error= -err;
		rth->rt_flags 	&= ~RTCF_LOCAL;
	}
	rth->rt_type	= res.type;
A
Al Viro 已提交
2005
	hash = rt_hash(daddr, saddr, fl.iif);
L
Linus Torvalds 已提交
2006 2007 2008 2009 2010 2011 2012
	err = rt_intern_hash(hash, rth, (struct rtable**)&skb->dst);
	goto done;

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

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

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

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

e_nobufs:
	err = -ENOBUFS;
	goto done;

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

A
Al Viro 已提交
2046
int ip_route_input(struct sk_buff *skb, __be32 daddr, __be32 saddr,
L
Linus Torvalds 已提交
2047 2048 2049 2050 2051 2052 2053
		   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
2054
	hash = rt_hash(daddr, saddr, iif);
L
Linus Torvalds 已提交
2055 2056 2057

	rcu_read_lock();
	for (rth = rcu_dereference(rt_hash_table[hash].chain); rth;
2058
	     rth = rcu_dereference(rth->u.dst.rt_next)) {
L
Linus Torvalds 已提交
2059 2060 2061 2062
		if (rth->fl.fl4_dst == daddr &&
		    rth->fl.fl4_src == saddr &&
		    rth->fl.iif == iif &&
		    rth->fl.oif == 0 &&
2063
		    rth->fl.mark == skb->mark &&
L
Linus Torvalds 已提交
2064
		    rth->fl.fl4_tos == tos) {
2065
			dst_use(&rth->u.dst, jiffies);
L
Linus Torvalds 已提交
2066 2067 2068 2069 2070 2071 2072 2073 2074 2075 2076 2077 2078 2079 2080 2081 2082 2083 2084 2085
			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.
	 */
2086
	if (ipv4_is_multicast(daddr)) {
L
Linus Torvalds 已提交
2087 2088 2089
		struct in_device *in_dev;

		rcu_read_lock();
2090
		if ((in_dev = __in_dev_get_rcu(dev)) != NULL) {
L
Linus Torvalds 已提交
2091
			int our = ip_check_mc(in_dev, daddr, saddr,
2092
				ip_hdr(skb)->protocol);
L
Linus Torvalds 已提交
2093 2094
			if (our
#ifdef CONFIG_IP_MROUTE
2095 2096
			    || (!ipv4_is_local_multicast(daddr) &&
				IN_DEV_MFORWARD(in_dev))
L
Linus Torvalds 已提交
2097 2098 2099 2100 2101 2102 2103 2104 2105 2106 2107 2108 2109 2110
#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,
2111
				   struct fib_result* res,
L
Linus Torvalds 已提交
2112
				   const struct flowi *fl,
2113 2114 2115
				   const struct flowi *oldflp,
				   struct net_device *dev_out,
				   unsigned flags)
L
Linus Torvalds 已提交
2116 2117 2118 2119 2120 2121
{
	struct rtable *rth;
	struct in_device *in_dev;
	u32 tos = RT_FL_TOS(oldflp);
	int err = 0;

2122
	if (ipv4_is_loopback(fl->fl4_src) && !(dev_out->flags&IFF_LOOPBACK))
L
Linus Torvalds 已提交
2123 2124
		return -EINVAL;

2125
	if (fl->fl4_dst == htonl(0xFFFFFFFF))
L
Linus Torvalds 已提交
2126
		res->type = RTN_BROADCAST;
2127
	else if (ipv4_is_multicast(fl->fl4_dst))
L
Linus Torvalds 已提交
2128
		res->type = RTN_MULTICAST;
2129
	else if (ipv4_is_lbcast(fl->fl4_dst) || ipv4_is_zeronet(fl->fl4_dst))
L
Linus Torvalds 已提交
2130 2131 2132 2133 2134 2135 2136 2137 2138 2139 2140 2141 2142 2143 2144 2145 2146 2147
		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;
2148
		if (!ip_check_mc(in_dev, oldflp->fl4_dst, oldflp->fl4_src,
L
Linus Torvalds 已提交
2149 2150 2151 2152 2153 2154 2155 2156 2157 2158 2159 2160 2161 2162 2163 2164 2165
				 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;
2166
	}
L
Linus Torvalds 已提交
2167

2168
	atomic_set(&rth->u.dst.__refcnt, 1);
L
Linus Torvalds 已提交
2169
	rth->u.dst.flags= DST_HOST;
2170
	if (IN_DEV_CONF_GET(in_dev, NOXFRM))
L
Linus Torvalds 已提交
2171
		rth->u.dst.flags |= DST_NOXFRM;
2172
	if (IN_DEV_CONF_GET(in_dev, NOPOLICY))
L
Linus Torvalds 已提交
2173 2174 2175 2176 2177 2178
		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;
2179
	rth->fl.mark    = oldflp->mark;
L
Linus Torvalds 已提交
2180 2181 2182
	rth->rt_dst	= fl->fl4_dst;
	rth->rt_src	= fl->fl4_src;
	rth->rt_iif	= oldflp->oif ? : dev_out->ifindex;
2183
	/* get references to the devices that are to be hold by the routing
L
Linus Torvalds 已提交
2184 2185 2186 2187 2188 2189 2190 2191 2192 2193 2194 2195 2196 2197 2198 2199 2200
	   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;
2201
		if (flags & RTCF_LOCAL &&
L
Linus Torvalds 已提交
2202 2203 2204 2205 2206 2207 2208
		    !(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) &&
2209
			    !ipv4_is_local_multicast(oldflp->fl4_dst)) {
L
Linus Torvalds 已提交
2210 2211 2212 2213 2214 2215 2216 2217 2218 2219 2220 2221 2222 2223 2224 2225 2226 2227 2228
				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;
}

2229 2230 2231 2232 2233 2234
static inline int ip_mkroute_output(struct rtable **rp,
				    struct fib_result* res,
				    const struct flowi *fl,
				    const struct flowi *oldflp,
				    struct net_device *dev_out,
				    unsigned flags)
L
Linus Torvalds 已提交
2235
{
C
Chuck Short 已提交
2236
	struct rtable *rth = NULL;
L
Linus Torvalds 已提交
2237 2238 2239
	int err = __mkroute_output(&rth, res, fl, oldflp, dev_out, flags);
	unsigned hash;
	if (err == 0) {
A
Al Viro 已提交
2240
		hash = rt_hash(oldflp->fl4_dst, oldflp->fl4_src, oldflp->oif);
L
Linus Torvalds 已提交
2241 2242
		err = rt_intern_hash(hash, rth, rp);
	}
2243

L
Linus Torvalds 已提交
2244 2245 2246 2247 2248 2249 2250
	return err;
}

/*
 * Major route resolver routine.
 */

2251 2252
static int ip_route_output_slow(struct net *net, struct rtable **rp,
				const struct flowi *oldflp)
L
Linus Torvalds 已提交
2253 2254 2255 2256 2257 2258 2259 2260 2261 2262
{
	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),
				      } },
2263
			    .mark = oldflp->mark,
2264
			    .iif = net->loopback_dev->ifindex,
L
Linus Torvalds 已提交
2265 2266 2267 2268 2269 2270 2271 2272 2273 2274 2275 2276 2277 2278 2279
			    .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;
2280
		if (ipv4_is_multicast(oldflp->fl4_src) ||
2281
		    ipv4_is_lbcast(oldflp->fl4_src) ||
2282
		    ipv4_is_zeronet(oldflp->fl4_src))
L
Linus Torvalds 已提交
2283 2284 2285
			goto out;

		/* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2286
		dev_out = ip_dev_find(net, oldflp->fl4_src);
2287
		if (dev_out == NULL)
L
Linus Torvalds 已提交
2288 2289 2290 2291
			goto out;

		/* I removed check for oif == dev_out->oif here.
		   It was wrong for two reasons:
2292 2293
		   1. ip_dev_find(net, saddr) can return wrong iface, if saddr
		      is assigned to multiple interfaces.
L
Linus Torvalds 已提交
2294 2295 2296 2297
		   2. Moreover, we are allowed to send packets with saddr
		      of another iface. --ANK
		 */

2298
		if (oldflp->oif == 0
2299 2300
		    && (ipv4_is_multicast(oldflp->fl4_dst) ||
			oldflp->fl4_dst == htonl(0xFFFFFFFF))) {
L
Linus Torvalds 已提交
2301 2302 2303 2304 2305 2306 2307 2308 2309 2310 2311 2312 2313 2314 2315 2316 2317 2318 2319 2320 2321 2322 2323 2324 2325
			/* 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) {
2326
		dev_out = dev_get_by_index(net, oldflp->oif);
L
Linus Torvalds 已提交
2327 2328 2329
		err = -ENODEV;
		if (dev_out == NULL)
			goto out;
2330 2331 2332

		/* RACE: Check return value of inet_select_addr instead. */
		if (__in_dev_get_rtnl(dev_out) == NULL) {
L
Linus Torvalds 已提交
2333 2334 2335 2336
			dev_put(dev_out);
			goto out;	/* Wrong error code */
		}

2337 2338
		if (ipv4_is_local_multicast(oldflp->fl4_dst) ||
		    oldflp->fl4_dst == htonl(0xFFFFFFFF)) {
L
Linus Torvalds 已提交
2339 2340 2341 2342 2343 2344
			if (!fl.fl4_src)
				fl.fl4_src = inet_select_addr(dev_out, 0,
							      RT_SCOPE_LINK);
			goto make_route;
		}
		if (!fl.fl4_src) {
2345
			if (ipv4_is_multicast(oldflp->fl4_dst))
L
Linus Torvalds 已提交
2346 2347 2348 2349 2350 2351 2352 2353 2354 2355 2356 2357 2358 2359
				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);
2360
		dev_out = net->loopback_dev;
L
Linus Torvalds 已提交
2361
		dev_hold(dev_out);
2362
		fl.oif = net->loopback_dev->ifindex;
L
Linus Torvalds 已提交
2363 2364 2365 2366 2367
		res.type = RTN_LOCAL;
		flags |= RTCF_LOCAL;
		goto make_route;
	}

2368
	if (fib_lookup(net, &fl, &res)) {
L
Linus Torvalds 已提交
2369 2370 2371 2372 2373 2374 2375 2376 2377 2378 2379 2380 2381 2382 2383 2384 2385 2386 2387 2388 2389 2390 2391 2392 2393 2394 2395 2396 2397 2398 2399 2400 2401 2402 2403 2404 2405 2406
		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);
2407
		dev_out = net->loopback_dev;
L
Linus Torvalds 已提交
2408 2409 2410 2411 2412 2413 2414 2415 2416 2417 2418 2419 2420 2421 2422
		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)
2423
		fib_select_default(net, &fl, &res);
L
Linus Torvalds 已提交
2424 2425 2426 2427 2428 2429 2430 2431 2432 2433 2434 2435 2436 2437 2438 2439 2440 2441 2442 2443 2444 2445

	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;
}

2446 2447
int __ip_route_output_key(struct net *net, struct rtable **rp,
			  const struct flowi *flp)
L
Linus Torvalds 已提交
2448 2449 2450 2451
{
	unsigned hash;
	struct rtable *rth;

A
Al Viro 已提交
2452
	hash = rt_hash(flp->fl4_dst, flp->fl4_src, flp->oif);
L
Linus Torvalds 已提交
2453 2454 2455

	rcu_read_lock_bh();
	for (rth = rcu_dereference(rt_hash_table[hash].chain); rth;
2456
		rth = rcu_dereference(rth->u.dst.rt_next)) {
L
Linus Torvalds 已提交
2457 2458 2459 2460
		if (rth->fl.fl4_dst == flp->fl4_dst &&
		    rth->fl.fl4_src == flp->fl4_src &&
		    rth->fl.iif == 0 &&
		    rth->fl.oif == flp->oif &&
2461
		    rth->fl.mark == flp->mark &&
L
Linus Torvalds 已提交
2462 2463
		    !((rth->fl.fl4_tos ^ flp->fl4_tos) &
			    (IPTOS_RT_MASK | RTO_ONLINK))) {
2464
			dst_use(&rth->u.dst, jiffies);
L
Linus Torvalds 已提交
2465 2466 2467 2468 2469 2470 2471 2472 2473
			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();

2474
	return ip_route_output_slow(net, rp, flp);
L
Linus Torvalds 已提交
2475 2476
}

2477 2478
EXPORT_SYMBOL_GPL(__ip_route_output_key);

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
static void ipv4_rt_blackhole_update_pmtu(struct dst_entry *dst, u32 mtu)
{
}

static struct dst_ops ipv4_dst_blackhole_ops = {
	.family			=	AF_INET,
	.protocol		=	__constant_htons(ETH_P_IP),
	.destroy		=	ipv4_dst_destroy,
	.check			=	ipv4_dst_check,
	.update_pmtu		=	ipv4_rt_blackhole_update_pmtu,
	.entry_size		=	sizeof(struct rtable),
};


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

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

		atomic_set(&new->__refcnt, 1);
		new->__use = 1;
2504 2505
		new->input = dst_discard;
		new->output = dst_discard;
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
		memcpy(new->metrics, ort->u.dst.metrics, RTAX_MAX*sizeof(u32));

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

		rt->fl = ort->fl;

		rt->idev = ort->idev;
		if (rt->idev)
			in_dev_hold(rt->idev);
		rt->rt_flags = ort->rt_flags;
		rt->rt_type = ort->rt_type;
		rt->rt_dst = ort->rt_dst;
		rt->rt_src = ort->rt_src;
		rt->rt_iif = ort->rt_iif;
		rt->rt_gateway = ort->rt_gateway;
		rt->rt_spec_dst = ort->rt_spec_dst;
		rt->peer = ort->peer;
		if (rt->peer)
			atomic_inc(&rt->peer->refcnt);

		dst_free(new);
	}

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

2536 2537
int ip_route_output_flow(struct net *net, struct rtable **rp, struct flowi *flp,
			 struct sock *sk, int flags)
L
Linus Torvalds 已提交
2538 2539 2540
{
	int err;

2541
	if ((err = __ip_route_output_key(net, rp, flp)) != 0)
L
Linus Torvalds 已提交
2542 2543 2544 2545 2546 2547 2548
		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;
2549 2550
		err = __xfrm_lookup((struct dst_entry **)rp, flp, sk,
				    flags ? XFRM_LOOKUP_WAIT : 0);
2551 2552 2553 2554
		if (err == -EREMOTE)
			err = ipv4_dst_blackhole(rp, flp, sk);

		return err;
L
Linus Torvalds 已提交
2555 2556 2557 2558 2559
	}

	return 0;
}

2560 2561
EXPORT_SYMBOL_GPL(ip_route_output_flow);

L
Linus Torvalds 已提交
2562 2563
int ip_route_output_key(struct rtable **rp, struct flowi *flp)
{
2564
	return ip_route_output_flow(&init_net, rp, flp, NULL, 0);
L
Linus Torvalds 已提交
2565 2566 2567
}

static int rt_fill_info(struct sk_buff *skb, u32 pid, u32 seq, int event,
2568
			int nowait, unsigned int flags)
L
Linus Torvalds 已提交
2569 2570 2571
{
	struct rtable *rt = (struct rtable*)skb->dst;
	struct rtmsg *r;
2572
	struct nlmsghdr *nlh;
2573 2574
	long expires;
	u32 id = 0, ts = 0, tsage = 0, error;
2575 2576 2577

	nlh = nlmsg_put(skb, pid, seq, event, sizeof(*r), flags);
	if (nlh == NULL)
2578
		return -EMSGSIZE;
2579 2580

	r = nlmsg_data(nlh);
L
Linus Torvalds 已提交
2581 2582 2583 2584 2585
	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;
2586
	NLA_PUT_U32(skb, RTA_TABLE, RT_TABLE_MAIN);
L
Linus Torvalds 已提交
2587 2588 2589 2590 2591 2592
	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;
2593

2594
	NLA_PUT_BE32(skb, RTA_DST, rt->rt_dst);
2595

L
Linus Torvalds 已提交
2596 2597
	if (rt->fl.fl4_src) {
		r->rtm_src_len = 32;
2598
		NLA_PUT_BE32(skb, RTA_SRC, rt->fl.fl4_src);
L
Linus Torvalds 已提交
2599 2600
	}
	if (rt->u.dst.dev)
2601
		NLA_PUT_U32(skb, RTA_OIF, rt->u.dst.dev->ifindex);
L
Linus Torvalds 已提交
2602 2603
#ifdef CONFIG_NET_CLS_ROUTE
	if (rt->u.dst.tclassid)
2604
		NLA_PUT_U32(skb, RTA_FLOW, rt->u.dst.tclassid);
L
Linus Torvalds 已提交
2605 2606
#endif
	if (rt->fl.iif)
2607
		NLA_PUT_BE32(skb, RTA_PREFSRC, rt->rt_spec_dst);
L
Linus Torvalds 已提交
2608
	else if (rt->rt_src != rt->fl.fl4_src)
2609
		NLA_PUT_BE32(skb, RTA_PREFSRC, rt->rt_src);
2610

L
Linus Torvalds 已提交
2611
	if (rt->rt_dst != rt->rt_gateway)
2612
		NLA_PUT_BE32(skb, RTA_GATEWAY, rt->rt_gateway);
2613

L
Linus Torvalds 已提交
2614
	if (rtnetlink_put_metrics(skb, rt->u.dst.metrics) < 0)
2615 2616
		goto nla_put_failure;

2617 2618
	error = rt->u.dst.error;
	expires = rt->u.dst.expires ? rt->u.dst.expires - jiffies : 0;
L
Linus Torvalds 已提交
2619
	if (rt->peer) {
2620
		id = rt->peer->ip_id_count;
L
Linus Torvalds 已提交
2621
		if (rt->peer->tcp_ts_stamp) {
2622
			ts = rt->peer->tcp_ts;
2623
			tsage = get_seconds() - rt->peer->tcp_ts_stamp;
L
Linus Torvalds 已提交
2624 2625
		}
	}
2626

L
Linus Torvalds 已提交
2627 2628
	if (rt->fl.iif) {
#ifdef CONFIG_IP_MROUTE
2629
		__be32 dst = rt->rt_dst;
L
Linus Torvalds 已提交
2630

2631
		if (ipv4_is_multicast(dst) && !ipv4_is_local_multicast(dst) &&
2632
		    IPV4_DEVCONF_ALL(&init_net, MC_FORWARDING)) {
L
Linus Torvalds 已提交
2633 2634 2635 2636 2637
			int err = ipmr_get_route(skb, r, nowait);
			if (err <= 0) {
				if (!nowait) {
					if (err == 0)
						return 0;
2638
					goto nla_put_failure;
L
Linus Torvalds 已提交
2639 2640
				} else {
					if (err == -EMSGSIZE)
2641
						goto nla_put_failure;
2642
					error = err;
L
Linus Torvalds 已提交
2643 2644 2645 2646
				}
			}
		} else
#endif
2647
			NLA_PUT_U32(skb, RTA_IIF, rt->fl.iif);
L
Linus Torvalds 已提交
2648 2649
	}

2650 2651 2652
	if (rtnl_put_cacheinfo(skb, &rt->u.dst, id, ts, tsage,
			       expires, error) < 0)
		goto nla_put_failure;
2653 2654

	return nlmsg_end(skb, nlh);
L
Linus Torvalds 已提交
2655

2656
nla_put_failure:
2657 2658
	nlmsg_cancel(skb, nlh);
	return -EMSGSIZE;
L
Linus Torvalds 已提交
2659 2660
}

2661
static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr* nlh, void *arg)
L
Linus Torvalds 已提交
2662
{
2663
	struct net *net = in_skb->sk->sk_net;
2664 2665
	struct rtmsg *rtm;
	struct nlattr *tb[RTA_MAX+1];
L
Linus Torvalds 已提交
2666
	struct rtable *rt = NULL;
A
Al Viro 已提交
2667 2668 2669
	__be32 dst = 0;
	__be32 src = 0;
	u32 iif;
2670
	int err;
L
Linus Torvalds 已提交
2671 2672
	struct sk_buff *skb;

2673 2674 2675
	if (net != &init_net)
		return -EINVAL;

2676 2677 2678 2679 2680 2681
	err = nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX, rtm_ipv4_policy);
	if (err < 0)
		goto errout;

	rtm = nlmsg_data(nlh);

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	skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
2683 2684 2685 2686
	if (skb == NULL) {
		err = -ENOBUFS;
		goto errout;
	}
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	/* Reserve room for dummy headers, this skb can pass
	   through good chunk of routing engine.
	 */
2691
	skb_reset_mac_header(skb);
2692
	skb_reset_network_header(skb);
2693 2694

	/* Bugfix: need to give ip_route_input enough of an IP header to not gag. */
2695
	ip_hdr(skb)->protocol = IPPROTO_ICMP;
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	skb_reserve(skb, MAX_HEADER + sizeof(struct iphdr));

2698 2699
	src = tb[RTA_SRC] ? nla_get_be32(tb[RTA_SRC]) : 0;
	dst = tb[RTA_DST] ? nla_get_be32(tb[RTA_DST]) : 0;
2700
	iif = tb[RTA_IIF] ? nla_get_u32(tb[RTA_IIF]) : 0;
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	if (iif) {
2703 2704
		struct net_device *dev;

2705
		dev = __dev_get_by_index(&init_net, iif);
2706 2707 2708 2709 2710
		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();
2716 2717 2718

		rt = (struct rtable*) skb->dst;
		if (err == 0 && rt->u.dst.error)
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			err = -rt->u.dst.error;
	} else {
2721 2722 2723 2724 2725 2726 2727 2728 2729 2730
		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);
	}
2733

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	if (err)
2735
		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,
2742
				RTM_NEWROUTE, 0, 0);
2743 2744
	if (err <= 0)
		goto errout_free;
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2746
	err = rtnl_unicast(skb, &init_net, NETLINK_CB(in_skb).pid);
2747
errout:
2748
	return err;
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2749

2750
errout_free:
L
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	kfree_skb(skb);
2752
	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];
2762 2763
	if (s_h < 0)
		s_h = 0;
L
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	s_idx = idx = cb->args[1];
2765
	for (h = s_h; h <= rt_hash_mask; h++) {
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		rcu_read_lock_bh();
		for (rt = rcu_dereference(rt_hash_table[h].chain), idx = 0; rt;
2768
		     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,
2773
					 cb->nlh->nlmsg_seq, RTM_NEWROUTE,
2774
					 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();
2782
		s_idx = 0;
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	}

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;
2807
	}
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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,
2818
						size_t newlen)
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{
	int delay;
	if (newlen != sizeof(int))
		return -EINVAL;
	if (get_user(delay, (int __user *)newval))
2824 2825
		return -EFAULT;
	rt_cache_flush(delay);
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	return 0;
}

ctl_table ipv4_route_table[] = {
2830
	{
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		.ctl_name 	= NET_IPV4_ROUTE_FLUSH,
		.procname	= "flush",
		.data		= &flush_delay,
		.maxlen		= sizeof(int),
2835
		.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 */
2875

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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
2998
struct ip_rt_acct *ip_rt_acct __read_mostly;
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2999 3000 3001 3002 3003 3004 3005 3006 3007 3008 3009 3010 3011 3012
#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)
{
3013
	int rc = 0;
L
Linus Torvalds 已提交
3014 3015 3016 3017 3018

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

#ifdef CONFIG_NET_CLS_ROUTE
3019
	ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct));
L
Linus Torvalds 已提交
3020 3021 3022 3023
	if (!ip_rt_acct)
		panic("IP: failed to allocate ip_rt_acct\n");
#endif

A
Alexey Dobriyan 已提交
3024 3025
	ipv4_dst_ops.kmem_cachep =
		kmem_cache_create("ip_dst_cache", sizeof(struct rtable), 0,
3026
				  SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
L
Linus Torvalds 已提交
3027

3028 3029
	ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep;

3030 3031 3032 3033 3034
	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) ?
3035
					15 : 17,
3036
					0,
3037 3038 3039
					&rt_hash_log,
					&rt_hash_mask,
					0);
3040 3041
	memset(rt_hash_table, 0, (rt_hash_mask + 1) * sizeof(struct rt_hash_bucket));
	rt_hash_lock_init();
L
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3042 3043 3044 3045 3046 3047 3048

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

	devinet_init();
	ip_fib_init();

3049 3050
	setup_timer(&rt_flush_timer, rt_run_flush, 0);
	setup_timer(&rt_secret_timer, rt_secret_rebuild, 0);
L
Linus Torvalds 已提交
3051 3052 3053 3054

	/* All the timers, started at system startup tend
	   to synchronize. Perturb it a bit.
	 */
3055 3056
	schedule_delayed_work(&expires_work,
		net_random() % ip_rt_gc_interval + ip_rt_gc_interval);
L
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3057 3058 3059 3060 3061

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

3062 3063
	if (ip_rt_proc_init(&init_net))
		printk(KERN_ERR "Unable to create route proc files\n");
L
Linus Torvalds 已提交
3064 3065 3066 3067
#ifdef CONFIG_XFRM
	xfrm_init();
	xfrm4_init();
#endif
3068 3069
	rtnl_register(PF_INET, RTM_GETROUTE, inet_rtm_getroute, NULL);

L
Linus Torvalds 已提交
3070 3071 3072 3073 3074 3075
	return rc;
}

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