path: root/net/xfrm/xfrm_interface.c

// SPDX-License-Identifier: GPL-2.0
/*
 *	XFRM virtual interface
 *
 *	Copyright (C) 2018 secunet Security Networks AG
 *
 *	Author:
 *	Steffen Klassert <steffen.klassert@secunet.com>
 */

#include <linux/module.h>
#include <linux/capability.h>
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/sockios.h>
#include <linux/icmp.h>
#include <linux/if.h>
#include <linux/in.h>
#include <linux/ip.h>
#include <linux/net.h>
#include <linux/in6.h>
#include <linux/netdevice.h>
#include <linux/if_link.h>
#include <linux/if_arp.h>
#include <linux/icmpv6.h>
#include <linux/init.h>
#include <linux/route.h>
#include <linux/rtnetlink.h>
#include <linux/netfilter_ipv6.h>
#include <linux/slab.h>
#include <linux/hash.h>

#include <linux/uaccess.h>
#include <linux/atomic.h>

#include <net/icmp.h>
#include <net/ip.h>
#include <net/ipv6.h>
#include <net/ip6_route.h>
#include <net/ip_tunnels.h>
#include <net/addrconf.h>
#include <net/xfrm.h>
#include <net/net_namespace.h>
#include <net/netns/generic.h>
#include <linux/etherdevice.h>

static int xfrmi_dev_init(struct net_device *dev);
static void xfrmi_dev_setup(struct net_device *dev);
static struct rtnl_link_ops xfrmi_link_ops __read_mostly;
static unsigned int xfrmi_net_id __read_mostly;
static const struct net_device_ops xfrmi_netdev_ops;

#define XFRMI_HASH_BITS	8
#define XFRMI_HASH_SIZE	BIT(XFRMI_HASH_BITS)

struct xfrmi_net {
	/* lists for storing interfaces in use */
	struct xfrm_if __rcu *xfrmi[XFRMI_HASH_SIZE];
};

#define for_each_xfrmi_rcu(start, xi) \
	for (xi = rcu_dereference(start); xi; xi = rcu_dereference(xi->next))

static u32 xfrmi_hash(u32 if_id)
{
	return hash_32(if_id, XFRMI_HASH_BITS);
}

static struct xfrm_if *xfrmi_lookup(struct net *net, struct xfrm_state *x)
{
	struct xfrmi_net *xfrmn = net_generic(net, xfrmi_net_id);
	struct xfrm_if *xi;

	for_each_xfrmi_rcu(xfrmn->xfrmi[xfrmi_hash(x->if_id)], xi) {
		if (x->if_id == xi->p.if_id &&
		    (xi->dev->flags & IFF_UP))
			return xi;
	}

	return NULL;
}

static struct xfrm_if *xfrmi_decode_session(struct sk_buff *skb,
					    unsigned short family)
{
	struct net_device *dev;
	int ifindex = 0;

	if (!secpath_exists(skb) || !skb->dev)
		return NULL;

	switch (family) {
	case AF_INET6:
		ifindex = inet6_sdif(skb);
		break;
	case AF_INET:
		ifindex = inet_sdif(skb);
		break;
	}

	if (ifindex) {
		struct net *net = xs_net(xfrm_input_state(skb));

		dev = dev_get_by_index_rcu(net, ifindex);
	} else {
		dev = skb->dev;
	}

	if (!dev || !(dev->flags & IFF_UP))
		return NULL;
	if (dev->netdev_ops != &xfrmi_netdev_ops)
		return NULL;

	return netdev_priv(dev);
}

static void xfrmi_link(struct xfrmi_net *xfrmn, struct xfrm_if *xi)
{
	struct xfrm_if __rcu **xip = &xfrmn->xfrmi[xfrmi_hash(xi->p.if_id)];

	rcu_assign_pointer(xi->next , rtnl_dereference(*xip));
	rcu_assign_pointer(*xip, xi);
}

static void xfrmi_unlink(struct xfrmi_net *xfrmn, struct xfrm_if *xi)
{
	struct xfrm_if __rcu **xip;
	struct xfrm_if *iter;

	for (xip = &xfrmn->xfrmi[xfrmi_hash(xi->p.if_id)];
	     (iter = rtnl_dereference(*xip)) != NULL;
	     xip = &iter->next) {
		if (xi == iter) {
			rcu_assign_pointer(*xip, xi->next);
			break;
		}
	}
}

static void xfrmi_dev_free(struct net_device *dev)
{
	struct xfrm_if *xi = netdev_priv(dev);

	gro_cells_destroy(&xi->gro_cells);
	free_percpu(dev->tstats);
}

static int xfrmi_create(struct net_device *dev)
{
	struct xfrm_if *xi = netdev_priv(dev);
	struct net *net = dev_net(dev);
	struct xfrmi_net *xfrmn = net_generic(net, xfrmi_net_id);
	int err;

	dev->rtnl_link_ops = &xfrmi_link_ops;
	err = register_netdevice(dev);
	if (err < 0)
		goto out;

	xfrmi_link(xfrmn, xi);

	return 0;

out:
	return err;
}

static struct xfrm_if *xfrmi_locate(struct net *net, struct xfrm_if_parms *p)
{
	struct xfrm_if __rcu **xip;
	struct xfrm_if *xi;
	struct xfrmi_net *xfrmn = net_generic(net, xfrmi_net_id);

	for (xip = &xfrmn->xfrmi[xfrmi_hash(p->if_id)];
	     (xi = rtnl_dereference(*xip)) != NULL;
	     xip = &xi->next)
		if (xi->p.if_id == p->if_id)
			return xi;

	return NULL;
}

static void xfrmi_dev_uninit(struct net_device *dev)
{
	struct xfrm_if *xi = netdev_priv<