path: root/net/ipv4/ip_tunnel.c

/*
 * Copyright (c) 2013 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
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/capability.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
#include <linux/skbuff.h>
#include <linux/netdevice.h>
#include <linux/in.h>
#include <linux/tcp.h>
#include <linux/udp.h>
#include <linux/if_arp.h>
#include <linux/mroute.h>
#include <linux/init.h>
#include <linux/in6.h>
#include <linux/inetdevice.h>
#include <linux/igmp.h>
#include <linux/netfilter_ipv4.h>
#include <linux/etherdevice.h>
#include <linux/if_ether.h>
#include <linux/if_vlan.h>
#include <linux/rculist.h>
#include <linux/err.h>

#include <net/sock.h>
#include <net/ip.h>
#include <net/icmp.h>
#include <net/protocol.h>
#include <net/ip_tunnels.h>
#include <net/arp.h>
#include <net/checksum.h>
#include <net/dsfield.h>
#include <net/inet_ecn.h>
#include <net/xfrm.h>
#include <net/net_namespace.h>
#include <net/netns/generic.h>
#include <net/rtnetlink.h>

#if IS_ENABLED(CONFIG_IPV6)
#include <net/ipv6.h>
#include <net/ip6_fib.h>
#include <net/ip6_route.h>
#endif

static unsigned int ip_tunnel_hash(__be32 key, __be32 remote)
{
	return hash_32((__force u32)key ^ (__force u32)remote,
			 IP_TNL_HASH_BITS);
}

static void __tunnel_dst_set(struct ip_tunnel_dst *idst,
			     struct dst_entry *dst)
{
	struct dst_entry *old_dst;

	if (dst) {
		if (dst->flags & DST_NOCACHE)
			dst = NULL;
		else
			dst_clone(dst);
	}
	old_dst = xchg((__force struct dst_entry **)&idst->dst, dst);
	dst_release(old_dst);
}

static void tunnel_dst_set(struct ip_tunnel *t, struct dst_entry *dst)
{
	__tunnel_dst_set(this_cpu_ptr(t->dst_cache), dst);
}

static void tunnel_dst_reset(struct ip_tunnel *t)
{
	tunnel_dst_set(t, NULL);
}

static void tunnel_dst_reset_all(struct ip_tunnel *t)
{
	int i;

	for_each_possible_cpu(i)
		__tunnel_dst_set(per_cpu_ptr(t->dst_cache, i), NULL);
}

static struct rtable *tunnel_rtable_get(struct ip_tunnel *t, u32 cookie)
{
	struct dst_entry *dst;

	rcu_read_lock();
	dst = rcu_dereference(this_cpu_ptr(t->dst_cache)->dst);
	if (dst) {
		if (dst->obsolete && dst->ops->check(dst, cookie) == NULL) {
			rcu_read_unlock();
			tunnel_dst_reset(t);
			return NULL;
		}
		dst_hold(dst);
	}
	rcu_read_unlock();
	return (struct rtable *)dst;
}

/* Often modified stats are per cpu, other are shared (netdev->stats) */
struct rtnl_link_stats64 *ip_tunnel_get_stats64(struct net_device *dev,
						struct rtnl_link_stats64 *tot)
{
	int i;

	for_each_possible_cpu(i) {
		const struct pcpu_sw_netstats *tstats =
						   per_cpu_ptr(dev->tstats, i);
		u64 rx_packets, rx_bytes, tx_packets, tx_bytes;
		unsigned int start;

		do {
			start = u64_stats_fetch_begin_bh(&tstats->syncp);
			rx_packets = tstats->rx_packets;
			tx_packets = tstats->tx_packets;
			rx_bytes = tstats->rx_bytes;
			tx_bytes = tstats->tx_bytes;
		} while (u64_stats_fetch_retry_bh(&tstats->syncp, start));

		tot->rx_packets += rx_packets;
		tot->tx_packets += tx_packets;
		tot->rx_bytes   += rx_bytes;
		tot->