net/xfrm/xfrm_device.c - kernel/msm-5.4 - Gitiles

 /*
  * xfrm_device.c - IPsec device offloading code.
  *
  * Copyright (c) 2015 secunet Security Networks AG
  *
  * Author:
  * Steffen Klassert <steffen.klassert@secunet.com>
  *
  * 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/errno.h>
 #include <linux/module.h>
 #include <linux/netdevice.h>
 #include <linux/skbuff.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>
 #include <net/dst.h>
 #include <net/xfrm.h>
 #include <linux/notifier.h>

 #ifdef CONFIG_XFRM_OFFLOAD
 static void __xfrm_transport_prep(struct xfrm_state *x, struct sk_buff *skb,
 				  unsigned int hsize)
 {
 	struct xfrm_offload *xo = xfrm_offload(skb);

 	skb_reset_mac_len(skb);
 	pskb_pull(skb, skb->mac_len + hsize + x->props.header_len);

 	if (xo->flags & XFRM_GSO_SEGMENT) {
 		skb_reset_transport_header(skb);
 		skb->transport_header -= x->props.header_len;
 	}
 }

 static void __xfrm_mode_tunnel_prep(struct xfrm_state *x, struct sk_buff *skb,
 				    unsigned int hsize)

 {
 	struct xfrm_offload *xo = xfrm_offload(skb);

 	if (xo->flags & XFRM_GSO_SEGMENT)
 		skb->transport_header = skb->network_header + hsize;

 	skb_reset_mac_len(skb);
 	pskb_pull(skb, skb->mac_len + x->props.header_len);
 }

 /* Adjust pointers into the packet when IPsec is done at layer2 */
 static void xfrm_outer_mode_prep(struct xfrm_state *x, struct sk_buff *skb)
 {
 	switch (x->outer_mode->encap) {
 	case XFRM_MODE_TUNNEL:
 		if (x->outer_mode->family == AF_INET)
 			return __xfrm_mode_tunnel_prep(x, skb,
 						       sizeof(struct iphdr));
 		if (x->outer_mode->family == AF_INET6)
 			return __xfrm_mode_tunnel_prep(x, skb,
 						       sizeof(struct ipv6hdr));
 		break;
 	case XFRM_MODE_TRANSPORT:
 		if (x->outer_mode->family == AF_INET)
 			return __xfrm_transport_prep(x, skb,
 						     sizeof(struct iphdr));
 		if (x->outer_mode->family == AF_INET6)
 			return __xfrm_transport_prep(x, skb,
 						     sizeof(struct ipv6hdr));
 		break;
 	case XFRM_MODE_ROUTEOPTIMIZATION:
 	case XFRM_MODE_IN_TRIGGER:
 	case XFRM_MODE_BEET:
 		break;
 	}
 }

 struct sk_buff *validate_xmit_xfrm(struct sk_buff *skb, netdev_features_t features, bool *again)
 {
 	int err;
 	unsigned long flags;
 	struct xfrm_state *x;
 	struct sk_buff *skb2;
 	struct softnet_data *sd;
 	netdev_features_t esp_features = features;
 	struct xfrm_offload *xo = xfrm_offload(skb);
 	struct sec_path *sp;

 	if (!xo)
 		return skb;

 	if (!(features & NETIF_F_HW_ESP))
 		esp_features = features & ~(NETIF_F_SG | NETIF_F_CSUM_MASK);

 	sp = skb_sec_path(skb);
 	x = sp->xvec[sp->len - 1];
 	if (xo->flags & XFRM_GRO || x->xso.flags & XFRM_OFFLOAD_INBOUND)
 		return skb;

 	local_irq_save(flags);
 	sd = this_cpu_ptr(&softnet_data);
 	err = !skb_queue_empty(&sd->xfrm_backlog);
 	local_irq_restore(flags);

 	if (err) {
 		*again = true;
 		return skb;
 	}

 	if (skb_is_gso(skb)) {
 		struct net_device *dev = skb->dev;

 		if (unlikely(x->xso.dev != dev)) {
 			struct sk_buff *segs;

 			/* Packet got rerouted, fixup features and segment it. */
 			esp_features = esp_features & ~(NETIF_F_HW_ESP
 							| NETIF_F_GSO_ESP);

 			segs = skb_gso_segment(skb, esp_features);
 			if (IS_ERR(segs)) {
 				kfree_skb(skb);
 				atomic_long_inc(&dev->tx_dropped);
 				return NULL;
 			} else {
 				consume_skb(skb);
 				skb = segs;
 			}
 		}
 	}

 	if (!skb->next) {
 		esp_features |= skb->dev->gso_partial_features;
 		xfrm_outer_mode_prep(x, skb);

 		xo->flags |= XFRM_DEV_RESUME;

 		err = x->type_offload->xmit(x, skb, esp_features);
 		if (err) {
 			if (err == -EINPROGRESS)
 				return NULL;

 			XFRM_INC_STATS(xs_net(x), LINUX_MIB_XFRMOUTSTATEPROTOERROR);
 			kfree_skb(skb);
 			return NULL;
 		}

 		skb_push(skb, skb->data - skb_mac_header(skb));

 		return skb;
 	}

 	skb2 = skb;

 	do {
 		struct sk_buff *nskb = skb2->next;

 		esp_features |= skb->dev->gso_partial_features;
 		skb_mark_not_on_list(skb2);

 		xo = xfrm_offload(skb2);
 		xo->flags |= XFRM_DEV_RESUME;

 		xfrm_outer_mode_prep(x, skb2);

 		err = x->type_offload->xmit(x, skb2, esp_features);
 		if (!err) {
 			skb2->next = nskb;
 		} else if (err != -EINPROGRESS) {
 			XFRM_INC_STATS(xs_net(x), LINUX_MIB_XFRMOUTSTATEPROTOERROR);
 			skb2->next = nskb;
 			kfree_skb_list(skb2);
 			return NULL;
 		} else {
 			if (skb == skb2)
 				skb = nskb;

 			if (!skb)
 				return NULL;

 			goto skip_push;
 		}

 		skb_push(skb2, skb2->data - skb_mac_header(skb2));

 skip_push:
 		skb2 = nskb;
 	} while (skb2);

 	return skb;
 }
 EXPORT_SYMBOL_GPL(validate_xmit_xfrm);

 int xfrm_dev_state_add(struct net *net, struct xfrm_state *x,
 		       struct xfrm_user_offload *xuo)
 {
 	int err;
 	struct dst_entry *dst;
 	struct net_device *dev;
 	struct xfrm_state_offload *xso = &x->xso;
 	xfrm_address_t *saddr;
 	xfrm_address_t *daddr;

 	if (!x->type_offload)
 		return -EINVAL;

 	/* We don't yet support UDP encapsulation and TFC padding. */
 	if (x->encap || x->tfcpad)
 		return -EINVAL;

 	dev = dev_get_by_index(net, xuo->ifindex);
 	if (!dev) {
 		if (!(xuo->flags & XFRM_OFFLOAD_INBOUND)) {
 			saddr = &x->props.saddr;
 			daddr = &x->id.daddr;
 		} else {
 			saddr = &x->id.daddr;
 			daddr = &x->props.saddr;
 		}

 		dst = __xfrm_dst_lookup(net, 0, 0, saddr, daddr,
 					x->props.family,
 					xfrm_smark_get(0, x));
 		if (IS_ERR(dst))
 			return 0;

 		dev = dst->dev;

 		dev_hold(dev);
 		dst_release(dst);
 	}

 	if (!dev->xfrmdev_ops || !dev->xfrmdev_ops->xdo_dev_state_add) {
 		xso->dev = NULL;
 		dev_put(dev);
 		return 0;
 	}

 	if (x->props.flags & XFRM_STATE_ESN &&
 	    !dev->xfrmdev_ops->xdo_dev_state_advance_esn) {
 		xso->dev = NULL;
 		dev_put(dev);
 		return -EINVAL;
 	}

 	xso->dev = dev;
 	xso->num_exthdrs = 1;
 	xso->flags = xuo->flags;

 	err = dev->xfrmdev_ops->xdo_dev_state_add(x);
 	if (err) {
 		xso->num_exthdrs = 0;
 		xso->flags = 0;
 		xso->dev = NULL;
 		dev_put(dev);

 		if (err != -EOPNOTSUPP)
 			return err;
 	}

 	return 0;
 }
 EXPORT_SYMBOL_GPL(xfrm_dev_state_add);

 bool xfrm_dev_offload_ok(struct sk_buff *skb, struct xfrm_state *x)
 {
 	int mtu;
 	struct dst_entry *dst = skb_dst(skb);
 	struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 	struct net_device *dev = x->xso.dev;

 	if (!x->type_offload || x->encap)
 		return false;

 	if ((!dev || (dev == xfrm_dst_path(dst)->dev)) &&
 	    (!xdst->child->xfrm && x->type->get_mtu)) {
 		mtu = x->type->get_mtu(x, xdst->child_mtu_cached);

 		if (skb->len <= mtu)
 			goto ok;

 		if (skb_is_gso(skb) && skb_gso_validate_network_len(skb, mtu))
 			goto ok;
 	}

 	return false;

 ok:
 	if (dev && dev->xfrmdev_ops && dev->xfrmdev_ops->xdo_dev_offload_ok)
 		return x->xso.dev->xfrmdev_ops->xdo_dev_offload_ok(skb, x);

 	return true;
 }
 EXPORT_SYMBOL_GPL(xfrm_dev_offload_ok);

 void xfrm_dev_resume(struct sk_buff *skb)
 {
 	struct net_device *dev = skb->dev;
 	int ret = NETDEV_TX_BUSY;
 	struct netdev_queue *txq;
 	struct softnet_data *sd;
 	unsigned long flags;

 	rcu_read_lock();
 	txq = netdev_core_pick_tx(dev, skb, NULL);

 	HARD_TX_LOCK(dev, txq, smp_processor_id());
 	if (!netif_xmit_frozen_or_stopped(txq))
 		skb = dev_hard_start_xmit(skb, dev, txq, &ret);
 	HARD_TX_UNLOCK(dev, txq);

 	if (!dev_xmit_complete(ret)) {
 		local_irq_save(flags);
 		sd = this_cpu_ptr(&softnet_data);
 		skb_queue_tail(&sd->xfrm_backlog, skb);
 		raise_softirq_irqoff(NET_TX_SOFTIRQ);
 		local_irq_restore(flags);
 	}
 	rcu_read_unlock();
 }
 EXPORT_SYMBOL_GPL(xfrm_dev_resume);

 void xfrm_dev_backlog(struct softnet_data *sd)
 {
 	struct sk_buff_head *xfrm_backlog = &sd->xfrm_backlog;
 	struct sk_buff_head list;
 	struct sk_buff *skb;

 	if (skb_queue_empty(xfrm_backlog))
 		return;

 	__skb_queue_head_init(&list);

 	spin_lock(&xfrm_backlog->lock);
 	skb_queue_splice_init(xfrm_backlog, &list);
 	spin_unlock(&xfrm_backlog->lock);

 	while (!skb_queue_empty(&list)) {
 		skb = __skb_dequeue(&list);
 		xfrm_dev_resume(skb);
 	}

 }
 #endif

 static int xfrm_api_check(struct net_device *dev)
 {
 #ifdef CONFIG_XFRM_OFFLOAD
 	if ((dev->features & NETIF_F_HW_ESP_TX_CSUM) &&
 	    !(dev->features & NETIF_F_HW_ESP))
 		return NOTIFY_BAD;

 	if ((dev->features & NETIF_F_HW_ESP) &&
 	    (!(dev->xfrmdev_ops &&
 	       dev->xfrmdev_ops->xdo_dev_state_add &&
 	       dev->xfrmdev_ops->xdo_dev_state_delete)))
 		return NOTIFY_BAD;
 #else
 	if (dev->features & (NETIF_F_HW_ESP | NETIF_F_HW_ESP_TX_CSUM))
 		return NOTIFY_BAD;
 #endif

 	return NOTIFY_DONE;
 }

 static int xfrm_dev_register(struct net_device *dev)
 {
 	return xfrm_api_check(dev);
 }

 static int xfrm_dev_feat_change(struct net_device *dev)
 {
 	return xfrm_api_check(dev);
 }

 static int xfrm_dev_down(struct net_device *dev)
 {
 	if (dev->features & NETIF_F_HW_ESP)
 		xfrm_dev_state_flush(dev_net(dev), dev, true);

 	return NOTIFY_DONE;
 }

 static int xfrm_dev_event(struct notifier_block *this, unsigned long event, void *ptr)
 {
 	struct net_device *dev = netdev_notifier_info_to_dev(ptr);

 	switch (event) {
 	case NETDEV_REGISTER:
 		return xfrm_dev_register(dev);

 	case NETDEV_FEAT_CHANGE:
 		return xfrm_dev_feat_change(dev);

 	case NETDEV_DOWN:
 		return xfrm_dev_down(dev);
 	}
 	return NOTIFY_DONE;
 }

 static struct notifier_block xfrm_dev_notifier = {
 	.notifier_call	= xfrm_dev_event,
 };

 void __init xfrm_dev_init(void)
 {
 	register_netdevice_notifier(&xfrm_dev_notifier);
 }
	/*
	* xfrm_device.c - IPsec device offloading code.
	*
	* Copyright (c) 2015 secunet Security Networks AG
	*
	* Author:
	* Steffen Klassert <steffen.klassert@secunet.com>
	*
	* 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/errno.h>
	#include <linux/module.h>
	#include <linux/netdevice.h>
	#include <linux/skbuff.h>
	#include <linux/slab.h>
	#include <linux/spinlock.h>
	#include <net/dst.h>
	#include <net/xfrm.h>
	#include <linux/notifier.h>

	#ifdef CONFIG_XFRM_OFFLOAD
	static void __xfrm_transport_prep(struct xfrm_state x, struct sk_buff skb,
	unsigned int hsize)
	{
	struct xfrm_offload *xo = xfrm_offload(skb);

	skb_reset_mac_len(skb);
	pskb_pull(skb, skb->mac_len + hsize + x->props.header_len);

	if (xo->flags & XFRM_GSO_SEGMENT) {
	skb_reset_transport_header(skb);
	skb->transport_header -= x->props.header_len;
	}
	}

	static void __xfrm_mode_tunnel_prep(struct xfrm_state x, struct sk_buff skb,
	unsigned int hsize)

	{
	struct xfrm_offload *xo = xfrm_offload(skb);

	if (xo->flags & XFRM_GSO_SEGMENT)
	skb->transport_header = skb->network_header + hsize;

	skb_reset_mac_len(skb);
	pskb_pull(skb, skb->mac_len + x->props.header_len);
	}

	/* Adjust pointers into the packet when IPsec is done at layer2 */
	static void xfrm_outer_mode_prep(struct xfrm_state x, struct sk_buff skb)
	{
	switch (x->outer_mode->encap) {
	case XFRM_MODE_TUNNEL:
	if (x->outer_mode->family == AF_INET)
	return __xfrm_mode_tunnel_prep(x, skb,
	sizeof(struct iphdr));
	if (x->outer_mode->family == AF_INET6)
	return __xfrm_mode_tunnel_prep(x, skb,
	sizeof(struct ipv6hdr));
	break;
	case XFRM_MODE_TRANSPORT:
	if (x->outer_mode->family == AF_INET)
	return __xfrm_transport_prep(x, skb,
	sizeof(struct iphdr));
	if (x->outer_mode->family == AF_INET6)
	return __xfrm_transport_prep(x, skb,
	sizeof(struct ipv6hdr));
	break;
	case XFRM_MODE_ROUTEOPTIMIZATION:
	case XFRM_MODE_IN_TRIGGER:
	case XFRM_MODE_BEET:
	break;
	}
	}

	struct sk_buff validate_xmit_xfrm(struct sk_buff skb, netdev_features_t features, bool *again)
	{
	int err;
	unsigned long flags;
	struct xfrm_state *x;
	struct sk_buff *skb2;
	struct softnet_data *sd;
	netdev_features_t esp_features = features;
	struct xfrm_offload *xo = xfrm_offload(skb);
	struct sec_path *sp;

	if (!xo)
	return skb;

	if (!(features & NETIF_F_HW_ESP))
	esp_features = features & ~(NETIF_F_SG \| NETIF_F_CSUM_MASK);

	sp = skb_sec_path(skb);
	x = sp->xvec[sp->len - 1];
	if (xo->flags & XFRM_GRO \|\| x->xso.flags & XFRM_OFFLOAD_INBOUND)
	return skb;

	local_irq_save(flags);
	sd = this_cpu_ptr(&softnet_data);
	err = !skb_queue_empty(&sd->xfrm_backlog);
	local_irq_restore(flags);

	if (err) {
	*again = true;
	return skb;
	}

	if (skb_is_gso(skb)) {
	struct net_device *dev = skb->dev;

	if (unlikely(x->xso.dev != dev)) {
	struct sk_buff *segs;

	/* Packet got rerouted, fixup features and segment it. */
	esp_features = esp_features & ~(NETIF_F_HW_ESP
	\| NETIF_F_GSO_ESP);

	segs = skb_gso_segment(skb, esp_features);
	if (IS_ERR(segs)) {
	kfree_skb(skb);
	atomic_long_inc(&dev->tx_dropped);
	return NULL;
	} else {
	consume_skb(skb);
	skb = segs;
	}
	}
	}

	if (!skb->next) {
	esp_features \|= skb->dev->gso_partial_features;
	xfrm_outer_mode_prep(x, skb);

	xo->flags \|= XFRM_DEV_RESUME;

	err = x->type_offload->xmit(x, skb, esp_features);
	if (err) {
	if (err == -EINPROGRESS)
	return NULL;

	XFRM_INC_STATS(xs_net(x), LINUX_MIB_XFRMOUTSTATEPROTOERROR);
	kfree_skb(skb);
	return NULL;
	}

	skb_push(skb, skb->data - skb_mac_header(skb));

	return skb;
	}

	skb2 = skb;

	do {
	struct sk_buff *nskb = skb2->next;

	esp_features \|= skb->dev->gso_partial_features;
	skb_mark_not_on_list(skb2);

	xo = xfrm_offload(skb2);
	xo->flags \|= XFRM_DEV_RESUME;

	xfrm_outer_mode_prep(x, skb2);

	err = x->type_offload->xmit(x, skb2, esp_features);
	if (!err) {
	skb2->next = nskb;
	} else if (err != -EINPROGRESS) {
	XFRM_INC_STATS(xs_net(x), LINUX_MIB_XFRMOUTSTATEPROTOERROR);
	skb2->next = nskb;
	kfree_skb_list(skb2);
	return NULL;
	} else {
	if (skb == skb2)
	skb = nskb;

	if (!skb)
	return NULL;

	goto skip_push;
	}

	skb_push(skb2, skb2->data - skb_mac_header(skb2));

	skip_push:
	skb2 = nskb;
	} while (skb2);

	return skb;
	}
	EXPORT_SYMBOL_GPL(validate_xmit_xfrm);

	int xfrm_dev_state_add(struct net net, struct xfrm_state x,
	struct xfrm_user_offload *xuo)
	{
	int err;
	struct dst_entry *dst;
	struct net_device *dev;
	struct xfrm_state_offload *xso = &x->xso;
	xfrm_address_t *saddr;
	xfrm_address_t *daddr;

	if (!x->type_offload)
	return -EINVAL;

	/* We don't yet support UDP encapsulation and TFC padding. */
	if (x->encap \|\| x->tfcpad)
	return -EINVAL;

	dev = dev_get_by_index(net, xuo->ifindex);
	if (!dev) {
	if (!(xuo->flags & XFRM_OFFLOAD_INBOUND)) {
	saddr = &x->props.saddr;
	daddr = &x->id.daddr;
	} else {
	saddr = &x->id.daddr;
	daddr = &x->props.saddr;
	}

	dst = __xfrm_dst_lookup(net, 0, 0, saddr, daddr,
	x->props.family,
	xfrm_smark_get(0, x));
	if (IS_ERR(dst))
	return 0;

	dev = dst->dev;

	dev_hold(dev);
	dst_release(dst);
	}

	if (!dev->xfrmdev_ops \|\| !dev->xfrmdev_ops->xdo_dev_state_add) {
	xso->dev = NULL;
	dev_put(dev);
	return 0;
	}

	if (x->props.flags & XFRM_STATE_ESN &&
	!dev->xfrmdev_ops->xdo_dev_state_advance_esn) {
	xso->dev = NULL;
	dev_put(dev);
	return -EINVAL;
	}

	xso->dev = dev;
	xso->num_exthdrs = 1;
	xso->flags = xuo->flags;

	err = dev->xfrmdev_ops->xdo_dev_state_add(x);
	if (err) {
	xso->num_exthdrs = 0;
	xso->flags = 0;
	xso->dev = NULL;
	dev_put(dev);

	if (err != -EOPNOTSUPP)
	return err;
	}

	return 0;
	}
	EXPORT_SYMBOL_GPL(xfrm_dev_state_add);

	bool xfrm_dev_offload_ok(struct sk_buff skb, struct xfrm_state x)
	{
	int mtu;
	struct dst_entry *dst = skb_dst(skb);
	struct xfrm_dst xdst = (struct xfrm_dst )dst;
	struct net_device *dev = x->xso.dev;

	if (!x->type_offload \|\| x->encap)
	return false;

	if ((!dev \|\| (dev == xfrm_dst_path(dst)->dev)) &&
	(!xdst->child->xfrm && x->type->get_mtu)) {
	mtu = x->type->get_mtu(x, xdst->child_mtu_cached);

	if (skb->len <= mtu)
	goto ok;

	if (skb_is_gso(skb) && skb_gso_validate_network_len(skb, mtu))
	goto ok;
	}

	return false;

	ok:
	if (dev && dev->xfrmdev_ops && dev->xfrmdev_ops->xdo_dev_offload_ok)
	return x->xso.dev->xfrmdev_ops->xdo_dev_offload_ok(skb, x);

	return true;
	}
	EXPORT_SYMBOL_GPL(xfrm_dev_offload_ok);

	void xfrm_dev_resume(struct sk_buff *skb)
	{
	struct net_device *dev = skb->dev;
	int ret = NETDEV_TX_BUSY;
	struct netdev_queue *txq;
	struct softnet_data *sd;
	unsigned long flags;

	rcu_read_lock();
	txq = netdev_core_pick_tx(dev, skb, NULL);

	HARD_TX_LOCK(dev, txq, smp_processor_id());
	if (!netif_xmit_frozen_or_stopped(txq))
	skb = dev_hard_start_xmit(skb, dev, txq, &ret);
	HARD_TX_UNLOCK(dev, txq);

	if (!dev_xmit_complete(ret)) {
	local_irq_save(flags);
	sd = this_cpu_ptr(&softnet_data);
	skb_queue_tail(&sd->xfrm_backlog, skb);
	raise_softirq_irqoff(NET_TX_SOFTIRQ);
	local_irq_restore(flags);
	}
	rcu_read_unlock();
	}
	EXPORT_SYMBOL_GPL(xfrm_dev_resume);

	void xfrm_dev_backlog(struct softnet_data *sd)
	{
	struct sk_buff_head *xfrm_backlog = &sd->xfrm_backlog;
	struct sk_buff_head list;
	struct sk_buff *skb;

	if (skb_queue_empty(xfrm_backlog))
	return;

	__skb_queue_head_init(&list);

	spin_lock(&xfrm_backlog->lock);
	skb_queue_splice_init(xfrm_backlog, &list);
	spin_unlock(&xfrm_backlog->lock);

	while (!skb_queue_empty(&list)) {
	skb = __skb_dequeue(&list);
	xfrm_dev_resume(skb);
	}

	}
	#endif

	static int xfrm_api_check(struct net_device *dev)
	{
	#ifdef CONFIG_XFRM_OFFLOAD
	if ((dev->features & NETIF_F_HW_ESP_TX_CSUM) &&
	!(dev->features & NETIF_F_HW_ESP))
	return NOTIFY_BAD;

	if ((dev->features & NETIF_F_HW_ESP) &&
	(!(dev->xfrmdev_ops &&
	dev->xfrmdev_ops->xdo_dev_state_add &&
	dev->xfrmdev_ops->xdo_dev_state_delete)))
	return NOTIFY_BAD;
	#else
	if (dev->features & (NETIF_F_HW_ESP \| NETIF_F_HW_ESP_TX_CSUM))
	return NOTIFY_BAD;
	#endif

	return NOTIFY_DONE;
	}

	static int xfrm_dev_register(struct net_device *dev)
	{
	return xfrm_api_check(dev);
	}

	static int xfrm_dev_feat_change(struct net_device *dev)
	{
	return xfrm_api_check(dev);
	}

	static int xfrm_dev_down(struct net_device *dev)
	{
	if (dev->features & NETIF_F_HW_ESP)
	xfrm_dev_state_flush(dev_net(dev), dev, true);

	return NOTIFY_DONE;
	}

	static int xfrm_dev_event(struct notifier_block this, unsigned long event, void ptr)
	{
	struct net_device *dev = netdev_notifier_info_to_dev(ptr);

	switch (event) {
	case NETDEV_REGISTER:
	return xfrm_dev_register(dev);

	case NETDEV_FEAT_CHANGE:
	return xfrm_dev_feat_change(dev);

	case NETDEV_DOWN:
	return xfrm_dev_down(dev);
	}
	return NOTIFY_DONE;
	}

	static struct notifier_block xfrm_dev_notifier = {
	.notifier_call = xfrm_dev_event,
	};

	void __init xfrm_dev_init(void)
	{
	register_netdevice_notifier(&xfrm_dev_notifier);
	}