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.
 *
 * 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/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/init.h>
#include <linux/list.h>
#include <linux/slab.h>

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

#ifndef CONFIG_IP_MULTIPLE_TABLES

static int __net_init fib4_rules_init(struct net *net)
{
	struct fib_table *local_table, *main_table;

	local_table = fib_hash_table(RT_TABLE_LOCAL);
	if (local_table == NULL)
		return -ENOMEM;

	main_table  = fib_hash_table(RT_TABLE_MAIN);
	if (main_table == NULL)
		goto fail;

	hlist_add_head_rcu(&local_table->tb_hlist,
				&net->ipv4.fib_table_hash[TABLE_LOCAL_INDEX]);
	hlist_add_head_rcu(&main_table->tb_hlist,
				&net->ipv4.fib_table_hash[TABLE_MAIN_INDEX]);
	return 0;

fail:
	kfree(local_table);
	return -ENOMEM;
}
#else

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

	if (id == 0)
		id = RT_TABLE_MAIN;
	tb = fib_get_table(net, id);
	if (tb)
		return tb;

	tb = fib_hash_table(id);
	if (!tb)
		return NULL;
	h = id & (FIB_TABLE_HASHSZ - 1);
	hlist_add_head_rcu(&tb->tb_hlist, &net->ipv4.fib_table_hash[h]);
	return tb;
}

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

	if (id == 0)
		id = RT_TABLE_MAIN;
	h = id & (FIB_TABLE_HASHSZ - 1);

	rcu_read_lock();
	head = &net->ipv4.fib_table_hash[h];
	hlist_for_each_entry_rcu(tb, node, head, tb_hlist) {
		if (tb->tb_id == id) {
			rcu_read_unlock();
			return tb;
		}
	}
	rcu_read_unlock();
	return NULL;
}
#endif /* CONFIG_IP_MULTIPLE_TABLES */

void fib_select_default(struct net *net,
			const struct flowi *flp, struct fib_result *res)
{
	struct fib_table *tb;
	int table = RT_TABLE_MAIN;
#ifdef CONFIG_IP_MULTIPLE_TABLES
	if (res->r == NULL || res->r->action != FR_ACT_TO_TBL)
		return;
	table = res->r->table;
#endif
	tb = fib_get_table(net, table);
	if (FIB_RES_GW(*res) && FIB_RES_NH(*res).nh_scope == RT_SCOPE_LINK)
		fib_table_select_default(tb, flp, res);
}

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