path: root/net/ipv4/fib_semantics.c

/*
 * INET		An implementation of the TCP/IP protocol suite for the LINUX
 *		operating system.  INET is implemented using the  BSD Socket
 *		interface as the means of communication with the user level.
 *
 *		IPv4 Forwarding Information Base: semantics.
 *
 * Authors:	Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
 *
 *		This program is free software; you can redistribute it and/or
 *		modify it under the terms of the GNU General Public License
 *		as published by the Free Software Foundation; either version
 *		2 of the License, or (at your option) any later version.
 */

#include <asm/uaccess.h>
#include <asm/system.h>
#include <linux/bitops.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/jiffies.h>
#include <linux/mm.h>
#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/inetdevice.h>
#include <linux/netdevice.h>
#include <linux/if_arp.h>
#include <linux/proc_fs.h>
#include <linux/skbuff.h>
#include <linux/init.h>

#include <net/arp.h>
#include <net/ip.h>
#include <net/protocol.h>
#include <net/route.h>
#include <net/tcp.h>
#include <net/sock.h>
#include <net/ip_fib.h>
#include <net/netlink.h>
#include <net/nexthop.h>

#include "fib_lookup.h"

static DEFINE_SPINLOCK(fib_info_lock);
static struct hlist_head *fib_info_hash;
static struct hlist_head *fib_info_laddrhash;
static unsigned int fib_hash_size;
static unsigned int fib_info_cnt;

#define DEVINDEX_HASHBITS 8
#define DEVINDEX_HASHSIZE (1U << DEVINDEX_HASHBITS)
static struct hlist_head fib_info_devhash[DEVINDEX_HASHSIZE];

#ifdef CONFIG_IP_ROUTE_MULTIPATH

static DEFINE_SPINLOCK(fib_multipath_lock);

#define for_nexthops(fi) { int nhsel; const struct fib_nh * nh; \
for (nhsel=0, nh = (fi)->fib_nh; nhsel < (fi)->fib_nhs; nh++, nhsel++)

#define change_nexthops(fi) { int nhsel; struct fib_nh * nh; \
for (nhsel=0, nh = (struct fib_nh *)((fi)->fib_nh); nhsel < (fi)->fib_nhs; nh++, nhsel++)

#else /* CONFIG_IP_ROUTE_MULTIPATH */

/* Hope, that gcc will optimize it to get rid of dummy loop */

#define for_nexthops(fi) { int nhsel = 0; const struct fib_nh * nh = (fi)->fib_nh; \
for (nhsel=0; nhsel < 1; nhsel++)

#define change_nexthops(fi) { int nhsel = 0; struct fib_nh * nh = (struct fib_nh *)((fi)->fib_nh); \
for (nhsel=0; nhsel < 1; nhsel++)

#endif /* CONFIG_IP_ROUTE_MULTIPATH */

#define endfor_nexthops(fi) }


static const struct
{
	int	error;
	u8	scope;
} fib_props[RTN_MAX + 1] = {
	{
		.error	= 0,
		.scope	= RT_SCOPE_NOWHERE,
	},	/* RTN_UNSPEC */
	{
		.error	= 0,
		.scope	= RT_SCOPE_UNIVERSE,
	},	/* RTN_UNICAST */
	{
		.error	= 0,
		.scope	= RT_SCOPE_HOST,
	},	/* RTN_LOCAL */
	{
		.error	= 0,
		.scope	= RT_SCOPE_LINK,
	},	/* RTN_BROADCAST */
	{
		.error	= 0,
		.scope	= RT_SCOPE_LINK,
	},	/* RTN_ANYCAST */
	{
		.error	= 0,
		.scope	= RT_SCOPE_UNIVERSE,
	},	/* RTN_MULTICAST */
	{
		.error	= -EINVAL,
		.scope	= RT_SCOPE_UNIVERSE,
	},	/* RTN_BLACKHOLE */
	{
		.error	= -EHOSTUNREACH,
		.scope	= RT_SCOPE_UNIVERSE,
	},	/* RTN_UNREACHABLE */
	{
		.error	= -EACCES,
		.scope	= RT_SCOPE_UNIVERSE,
	},	/* RTN_PROHIBIT */
	{
		.error	= -EAGAIN,
		.scope	= RT_SCOPE_UNIVERSE,
	},	/* RTN_THROW */
	{
		.error	= -EINVAL,
		.scope	= RT_SCOPE_NOWHERE,
	},	/* RTN_NAT */
	{
		.error	= -EINVAL,
		.scope	= RT_SCOPE_NOWHERE,
	},	/* RTN_XRESOLVE */
};


/* Release a nexthop info record */

void free_fib_info(struct fib_info *fi)
{
	if (fi->fib_dead == 0) {
		printk(KERN_WARNING "Freeing alive fib_info %p\n", fi);
		return;
	}
	change_nexthops(fi) {
		if (nh->nh_dev)
			dev_put(nh->nh_dev);
		nh->nh_dev = NULL;
	} endfor_nexthops(fi);
	fib_info_cnt--;
	release_net(fi->fib_net);
	kfree(fi);
}

void fib_release_info(struct fib_info *fi)
{
	spin_lock_bh(&fib_info_lock);
	if (fi && --fi->fib_treeref == 0) {
		hlist_del(&fi->fib_hash);
		if (fi->fib_prefsrc)
			hlist_del(&fi->fib_lhash);
		change_nexthops(fi) {
			if (!nh->nh_dev)
				continue;
			hlist_del(&nh->nh_hash);
		} endfor_nexthops(fi)
		fi->fib_dead = 1;
		fib_info_put(fi);
	}
	spin_unlock_bh(&fib_info_lock);
}

static __inline__ int nh_comp(const struct fib_info *fi, const struct fib_info *ofi)
{
	const struct fib_nh *onh = ofi->fib_nh;

	for_nexthops(fi) {
		if (nh->nh_oif != onh->nh_oif ||
		    nh->nh_gw  != onh->nh_gw ||
		    nh->nh_scope != onh->nh_scope ||
#ifdef CONFIG_IP_ROUTE_MULTIPATH
		    nh->nh_weight != onh->nh_weight ||
#endif
#ifdef CONFIG_NET_CLS_ROUTE
		    nh->nh_tclassid != onh->nh_tclassid ||
#endif
		    ((nh->nh_flags^onh->nh_flags)&~RTNH_F_DEAD))
			return -1;
		onh++;
	} endfor_nexthops(fi);
	return 0;
}

static inline unsigned int fib_devindex_hashfn(unsigned int val)
{
	unsigned int mask = DEVINDEX_HASHSIZE - 1;

	return (val ^
		(val >> DEVINDEX_HASHBITS) ^
		(val >> (DEVINDEX_HASHBITS * 2))) & mask;
}

static inline unsigned int fib_info_hashfn(const struct fib_info *fi)
{
	unsigned int mask = (fib_hash_size - 1);
	unsigned int val = fi->fib_nhs;

	val ^= fi->fib_protocol;
	val ^= (__force u32)fi->fib_prefsrc;
	val ^= fi->fib_priority;
	for_nexthops(fi) {
		val ^= fib_devindex_hashfn(nh->nh_oif);
	} endfor_nexthops(fi)

	return (val ^ (val >> 7) ^ (val >> 12)) & mask;
}

static struct fib_info *fib_find_info(const struct fib_info *nfi)
{
	struct hlist_head *head;
	struct hlist_node *node;
	struct fib_info *fi;
	<