path: root/net/ipv4/fib_frontend.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: FIB frontend.
 *
 * Version:	$Id: fib_frontend.c,v 1.26 2001/10/31 21:55:54 davem Exp $
 *
 * 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 <linux/module.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <linux/bitops.h>
#include <linux/capability.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/sched.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_addr.h>
#include <linux/if_arp.h>
#include <linux/skbuff.h>
#include <linux/netlink.h>
#include <linux/init.h>
#include <linux/list.h>

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

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

#ifndef CONFIG_IP_MULTIPLE_TABLES

struct fib_table *ip_fib_local_table;
struct fib_table *ip_fib_main_table;

#define FIB_TABLE_HASHSZ 1
static struct hlist_head fib_table_hash[FIB_TABLE_HASHSZ];

#else

#define FIB_TABLE_HASHSZ 256
static struct hlist_head fib_table_hash[FIB_TABLE_HASHSZ];

struct fib_table *fib_new_table(u32 id)
{
	struct fib_table *tb;
	unsigned int h;

	if (id == 0)
		id = RT_TABLE_MAIN;
	tb = fib_get_table(id);
	if (tb)
		return tb;
	tb = fib_hash_init(id);
	if (!tb)
		return NULL;
	h = id & (FIB_TABLE_HASHSZ - 1);
	hlist_add_head_rcu(&tb->tb_hlist, &fib_table_hash[h]);
	return tb;
}

struct fib_table *fib_get_table(u32 id)
{
	struct fib_table *tb;
	struct hlist_node *node;
	unsigned int h;

	if (id == 0)
		id = RT_TABLE_MAIN;
	h = id & (FIB_TABLE_HASHSZ - 1);
	rcu_read_lock();
	hlist_for_each_entry_rcu(tb, node, &fib_table_hash[h], tb_hlist) {
		if (tb->tb_id == id) {
			rcu_read_unlock();
			return tb;
		}
	}
	rcu_read_unlock();
	return NULL;
}
#endif /* CONFIG_IP_MULTIPLE_TABLES */

static void fib_flush(void)
{
	int flushed = 0;
	struct fib_table *tb;
	struct hlist_node *node;
	unsigned int h;

	for (h = 0; h < FIB_TABLE_HASHSZ; h++) {
		hlist_for_each_entry(tb, node, &fib_table_hash[h], tb_hlist)
			flushed += tb->tb_flush(tb);
	}

	if (flushed)
		rt_cache_flush(-1);
}

/*
 *	Find the first device with a given source address.
 */

struct net_device * ip_dev_find(__be32 addr)
{
	struct flowi fl = { .nl_u = { .ip4_u = { .daddr = addr } } };
	struct fib_result res;
	struct net_device *dev = NULL;

#ifdef CONFIG_IP_MULTIPLE_TABLES
	res.r = NULL;
#endif

	if (!ip_fib_local_table ||
	    ip_fib_local_table->tb_lookup(ip_fib_local_table, &fl, &res))
		return NULL;
	if (res.type != RTN_LOCAL)
		goto out;
	dev = FIB_RES_DEV(res);

	if (dev)
		dev_hold(dev);
out:
	fib_res_put(&res);
	return dev;
}

unsigned inet_addr_type(__be32 addr)
{
	struct flowi		fl = { .nl_u = { .ip4_u = { .daddr = addr } } };
	struct fib_result	res;
	unsigned ret = RTN_BROADCAST;

	if (ZERONET(addr) || BADCLASS(addr))
		return RTN_BROADCAST;
	if (MULTICAST(addr))
		return RTN_MULTICAST;

#ifdef CONFIG_IP_MULTIPLE_TABLES
	res.r = NULL;
#endif
	
	if (ip_fib_local_table) {
		ret = RTN_UNICAST;
		if (!ip_fib_local_table->tb_lookup(ip_fib_local_table,
						   &fl, &res)) {
			ret = res.type;
			fib_res_put(&res);
		}
	}
	return ret;
}

/* Given (packet source, input interface) and optional (dst, oif, tos):
   - (main) check, that source is valid i.e. not broadcast or our local
     address.
   - figure out what "logical" interface this packet arrived
     and calculate "specific destination" address.
   - check, that packet arrived from expected physical interface.
 */

int fib_validate_source(__be32 src, __be32 dst, u8 tos, int oif,
			struct net_device *dev, __be32 *spec_dst, u32 *itag)
{
	struct in_device *in_dev;
	struct flowi fl = { .nl_u = {