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>
This commit is contained in:
Pravin B Shelar 2013-02-14 14:02:41 +00:00 committed by David S. Miller
commit 68c3316311
12 changed files with 226 additions and 11 deletions

View file

@ -41,7 +41,7 @@ enum {
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 @@ enum {
#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 */

View file

@ -314,6 +314,8 @@ enum {
SKB_GSO_TCPV6 = 1 << 4,
SKB_GSO_FCOE = 1 << 5,
SKB_GSO_GRE = 1 << 6,
};
#if BITS_PER_LONG > 32
@ -2732,6 +2734,21 @@ static inline struct sec_path *skb_sec_path(struct sk_buff *skb)
}
#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;