xfrm: Add mode handlers for IPsec on layer 2

This patch adds a gso_segment and xmit callback for the
xfrm_mode and implement these functions for tunnel and
transport mode.

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

1 files changed, 32 insertions, 0 deletions

diff --git a/net/ipv4/xfrm4_mode_transport.c b/net/ipv4/xfrm4_mode_transport.c
index 4acc0508c5eb..6c2411d09386 100644
--- a/net/ipv4/xfrm4_mode_transport.c
+++ b/net/ipv4/xfrm4_mode_transport.c
@@ -12,6 +12,7 @@
 #include <net/dst.h>
 #include <net/ip.h>
 #include <net/xfrm.h>
+#include <net/protocol.h>
 
 /* Add encapsulation header.
  *
@@ -56,9 +57,40 @@ static int xfrm4_transport_input(struct xfrm_state *x, struct sk_buff *skb)
 	return 0;
 }
 
+static struct sk_buff *xfrm4_transport_gso_segment(struct xfrm_state *x,
+						   struct sk_buff *skb,
+						   netdev_features_t features)
+{
+	const struct net_offload *ops;
+	struct sk_buff *segs = ERR_PTR(-EINVAL);
+	struct xfrm_offload *xo = xfrm_offload(skb);
+
+	skb->transport_header += x->props.header_len;
+	ops = rcu_dereference(inet_offloads[xo->proto]);
+	if (likely(ops && ops->callbacks.gso_segment))
+		segs = ops->callbacks.gso_segment(skb, features);
+
+	return segs;
+}
+
+static void xfrm4_transport_xmit(struct xfrm_state *x, struct sk_buff *skb)
+{
+	struct xfrm_offload *xo = xfrm_offload(skb);
+
+	skb_reset_mac_len(skb);
+	pskb_pull(skb, skb->mac_len + sizeof(struct iphdr) + x->props.header_len);
+
+	if (xo->flags & XFRM_GSO_SEGMENT) {
+		 skb_reset_transport_header(skb);
+		 skb->transport_header -= x->props.header_len;
+	}
+}
+
 static struct xfrm_mode xfrm4_transport_mode = {
 	.input = xfrm4_transport_input,
 	.output = xfrm4_transport_output,
+	.gso_segment = xfrm4_transport_gso_segment,
+	.xmit = xfrm4_transport_xmit,
 	.owner = THIS_MODULE,
 	.encap = XFRM_MODE_TRANSPORT,
 };