v4 GRE: Add TCP segmentation offload for GRE
Following patch adds GRE protocol offload handler so that
skb_gso_segment() can segment GRE packets.
SKB GSO CB is added to keep track of total header length so that
skb_segment can push entire header. e.g. in case of GRE, skb_segment
need to push inner and outer headers to every segment.
New NETIF_F_GRE_GSO feature is added for devices which support HW
GRE TSO offload. Currently none of devices support it therefore GRE GSO
always fall backs to software GSO.
[ Compute pkt_len before ip_local_out() invocation. -DaveM ]
Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/netdev_features.h b/include/linux/netdev_features.h
index 5ac3212..3dd3934 100644
--- a/include/linux/netdev_features.h
+++ b/include/linux/netdev_features.h
@@ -41,7 +41,7 @@
NETIF_F_TSO_ECN_BIT, /* ... TCP ECN support */
NETIF_F_TSO6_BIT, /* ... TCPv6 segmentation */
NETIF_F_FSO_BIT, /* ... FCoE segmentation */
- NETIF_F_GSO_RESERVED1, /* ... free (fill GSO_MASK to 8 bits) */
+ NETIF_F_GSO_GRE_BIT, /* ... GRE with TSO */
/**/NETIF_F_GSO_LAST, /* [can't be last bit, see GSO_MASK] */
NETIF_F_GSO_RESERVED2 /* ... free (fill GSO_MASK to 8 bits) */
= NETIF_F_GSO_LAST,
@@ -102,6 +102,7 @@
#define NETIF_F_VLAN_CHALLENGED __NETIF_F(VLAN_CHALLENGED)
#define NETIF_F_RXFCS __NETIF_F(RXFCS)
#define NETIF_F_RXALL __NETIF_F(RXALL)
+#define NETIF_F_GRE_GSO __NETIF_F(GSO_GRE)
/* Features valid for ethtool to change */
/* = all defined minus driver/device-class-related */
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index ca6ee7d..821c7f4 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -314,6 +314,8 @@
SKB_GSO_TCPV6 = 1 << 4,
SKB_GSO_FCOE = 1 << 5,
+
+ SKB_GSO_GRE = 1 << 6,
};
#if BITS_PER_LONG > 32
@@ -2732,6 +2734,21 @@
}
#endif
+/* Keeps track of mac header offset relative to skb->head.
+ * It is useful for TSO of Tunneling protocol. e.g. GRE.
+ * For non-tunnel skb it points to skb_mac_header() and for
+ * tunnel skb it points to outer mac header. */
+struct skb_gso_cb {
+ int mac_offset;
+};
+#define SKB_GSO_CB(skb) ((struct skb_gso_cb *)(skb)->cb)
+
+static inline int skb_tnl_header_len(const struct sk_buff *inner_skb)
+{
+ return (skb_mac_header(inner_skb) - inner_skb->head) -
+ SKB_GSO_CB(inner_skb)->mac_offset;
+}
+
static inline bool skb_is_gso(const struct sk_buff *skb)
{
return skb_shinfo(skb)->gso_size;