/*
 * Copyright (c) 2007-2012 Nicira, Inc.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of version 2 of the GNU General Public
 * License as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301, USA
 */

#ifndef COMPAT_H
#define COMPAT_H 1

#include <linux/in.h>
#include <linux/in_route.h>
#include <linux/netlink.h>
#include <net/route.h>
#include <net/xfrm.h>

#if LINUX_VERSION_CODE >= KERNEL_VERSION(3,13,0)
#define GROUP_ID(grp)	0
#else
#define GROUP_ID(grp)	((grp)->id)
#endif

#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,36)
#define rt_dst(rt) (rt->dst)
#else
#define rt_dst(rt) (rt->u.dst)
#endif

#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,33)
#define inet_sport(sk)	(inet_sk(sk)->sport)
#else
#define inet_sport(sk)	(inet_sk(sk)->inet_sport)
#endif

static inline struct rtable *find_route(struct net *net,
					__be32 *saddr, __be32 daddr,
					u8 ipproto, u8 tos, u32 skb_mark)
{
	struct rtable *rt;
	/* Tunnel configuration keeps DSCP part of TOS bits, But Linux
	 * router expect RT_TOS bits only. */

#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,39)
	struct flowi fl = { .nl_u = { .ip4_u = {
					.daddr = daddr,
					.saddr = *saddr,
					.tos   = RT_TOS(tos) } },
					.mark = skb_mark,
					.proto = ipproto };

	if (unlikely(ip_route_output_key(net, &rt, &fl)))
		return ERR_PTR(-EADDRNOTAVAIL);
	*saddr = fl.nl_u.ip4_u.saddr;
	return rt;
#else
	struct flowi4 fl = { .daddr = daddr,
			     .saddr = *saddr,
			     .flowi4_tos = RT_TOS(tos),
			     .flowi4_mark = skb_mark,
			     .flowi4_proto = ipproto };

	rt = ip_route_output_key(net, &fl);
	*saddr = fl.saddr;
	return rt;
#endif
}
#endif /* compat.h */