xfrm: Add an IPsec hardware offloading API

This patch adds all the bits that are needed to do
IPsec hardware offload for IPsec states and ESP packets.
We add xfrmdev_ops to the net_device. xfrmdev_ops has
function pointers that are needed to manage the xfrm
states in the hardware and to do a per packet
offloading decision.

Joint work with:
Ilan Tayari <ilant@mellanox.com>
Guy Shapiro <guysh@mellanox.com>
Yossi Kuperman <yossiku@mellanox.com>

Signed-off-by: Guy Shapiro <guysh@mellanox.com>
Signed-off-by: Ilan Tayari <ilant@mellanox.com>
Signed-off-by: Yossi Kuperman <yossiku@mellanox.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

1 files changed, 137 insertions, 1 deletions

diff --git a/net/xfrm/xfrm_device.c b/net/xfrm/xfrm_device.c
index 34a260a61be9..9bac2ba9052c 100644
--- a/net/xfrm/xfrm_device.c
+++ b/net/xfrm/xfrm_device.c
@@ -22,13 +22,149 @@
 #include <net/xfrm.h>
 #include <linux/notifier.h>
 
+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 0;
+
+	/* We don't yet support UDP encapsulation, TFC padding and ESN. */
+	if (x->encap || x->tfcpad || (x->props.flags & XFRM_STATE_ESN))
+		return 0;
+
+	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);
+		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) {
+		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 ((x->xso.offload_handle && (dev == dst->path->dev)) &&
+	     !dst->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);
+
+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)
+{
+	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->hw_features & NETIF_F_HW_ESP)
+		xfrm_dev_state_flush(dev_net(dev), dev, true);
+
+	xfrm_garbage_collect(dev_net(dev));
+
+	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:
-		xfrm_garbage_collect(dev_net(dev));
+		return xfrm_dev_down(dev);
 	}
 	return NOTIFY_DONE;
 }