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/*
* 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
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);
if (!xo)
return skb;
if (!(features & NETIF_F_HW_ESP))
esp_features = features & ~(NETIF_F_SG | NETIF_F_CSUM_MASK);
x = skb->sp->xvec[skb->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.offload_handle || (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) {
x->outer_mode->xmit(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;
skb2->next = NULL;
xo = xfrm_offload(skb2);
xo->flags |= XFRM_DEV_RESUME;
x->outer_mode->xmit(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, TFC padding and ESN. */
if (x->encap || x->tfcpad || (x->props.flags & XFRM_STATE_ESN))
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, x->props.output_mark);
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;
}
xso->dev = dev;
xso->num_exthdrs = 1;
xso->flags = xuo->flags;
err = dev->xfrmdev_ops->xdo_dev_state_add(x);
if (err) {
dev_put(dev);
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 || (x->xso.offload_handle && (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_mtu(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_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_dev_register(struct net_device *dev)
{
if ((dev->features & NETIF_F_HW_ESP) && !dev->xfrmdev_ops)
return NOTIFY_BAD;
if ((dev->features & NETIF_F_HW_ESP_TX_CSUM) &&
!(dev->features & NETIF_F_HW_ESP))
return NOTIFY_BAD;
return NOTIFY_DONE;
}
static int xfrm_dev_unregister(struct net_device *dev)
{
xfrm_policy_cache_flush();
return NOTIFY_DONE;
}
static int xfrm_dev_feat_change(struct net_device *dev)
{
if ((dev->features & NETIF_F_HW_ESP) && !dev->xfrmdev_ops)
return NOTIFY_BAD;
else if (!(dev->features & NETIF_F_HW_ESP))
dev->xfrmdev_ops = NULL;
if ((dev->features & NETIF_F_HW_ESP_TX_CSUM) &&
!(dev->features & NETIF_F_HW_ESP))
return NOTIFY_BAD;
return NOTIFY_DONE;
}
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);
xfrm_policy_cache_flush();
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_UNREGISTER:
return xfrm_dev_unregister(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 __net_init xfrm_dev_init(void)
{
register_netdevice_notifier(&xfrm_dev_notifier);
}
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