[IPV6]: Added GSO support for TCPv6

This patch adds GSO support for IPv6 and TCPv6.  This is based on a patch
by Ananda Raju <Ananda.Raju@neterion.com>.  His original description is:

	This patch enables TSO over IPv6. Currently Linux network stacks
	restricts TSO over IPv6 by clearing of the NETIF_F_TSO bit from
	"dev->features". This patch will remove this restriction.

	This patch will introduce a new flag NETIF_F_TSO6 which will be used
	to check whether device supports TSO over IPv6. If device support TSO
	over IPv6 then we don't clear of NETIF_F_TSO and which will make the
	TCP layer to create TSO packets. Any device supporting TSO over IPv6
	will set NETIF_F_TSO6 flag in "dev->features" along with NETIF_F_TSO.

	In case when user disables TSO using ethtool, NETIF_F_TSO will get
	cleared from "dev->features". So even if we have NETIF_F_TSO6 we don't
	get TSO packets created by TCP layer.

	SKB_GSO_TCPV4 renamed to SKB_GSO_TCP to make it generic GSO packet.
	SKB_GSO_UDPV4 renamed to SKB_GSO_UDP as UFO is not a IPv4 feature.
	UFO is supported over IPv6 also

	The following table shows there is significant improvement in
	throughput with normal frames and CPU usage for both normal and jumbo.

	--------------------------------------------------
	|          |     1500        |      9600         |
	|          ------------------|-------------------|
	|          | thru     CPU    |  thru     CPU     |
	--------------------------------------------------
	| TSO OFF  | 2.00   5.5% id  |  5.66   20.0% id  |
	--------------------------------------------------
	| TSO ON   | 2.63   78.0 id  |  5.67   39.0% id  |
	--------------------------------------------------

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

4 files changed, 9 insertions, 8 deletions

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 6db03ab..85f99f6 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -315,9 +315,10 @@ struct net_device
 #define NETIF_F_GSO_SHIFT	16
 #define NETIF_F_GSO_MASK	0xffff0000
 #define NETIF_F_TSO		(SKB_GSO_TCPV4 << NETIF_F_GSO_SHIFT)
-#define NETIF_F_UFO		(SKB_GSO_UDPV4 << NETIF_F_GSO_SHIFT)
+#define NETIF_F_UFO		(SKB_GSO_UDP << NETIF_F_GSO_SHIFT)
 #define NETIF_F_GSO_ROBUST	(SKB_GSO_DODGY << NETIF_F_GSO_SHIFT)
-#define NETIF_F_TSO_ECN		(SKB_GSO_TCPV4_ECN << NETIF_F_GSO_SHIFT)
+#define NETIF_F_TSO_ECN		(SKB_GSO_TCP_ECN << NETIF_F_GSO_SHIFT)
+#define NETIF_F_TSO6		(SKB_GSO_TCPV6 << NETIF_F_GSO_SHIFT)
 
 #define NETIF_F_GEN_CSUM	(NETIF_F_NO_CSUM | NETIF_F_HW_CSUM)
 #define NETIF_F_ALL_CSUM	(NETIF_F_IP_CSUM | NETIF_F_GEN_CSUM)
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 59918be9..57d7d49 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -171,13 +171,15 @@ enum {
 
 enum {
 	SKB_GSO_TCPV4 = 1 << 0,
-	SKB_GSO_UDPV4 = 1 << 1,
+	SKB_GSO_UDP = 1 << 1,
 
 	/* This indicates the skb is from an untrusted source. */
 	SKB_GSO_DODGY = 1 << 2,
 
 	/* This indicates the tcp segment has CWR set. */
-	SKB_GSO_TCPV4_ECN = 1 << 3,
+	SKB_GSO_TCP_ECN = 1 << 3,
+
+	SKB_GSO_TCPV6 = 1 << 4,
 };
 
 /** 
diff --git a/include/net/ip6_route.h b/include/net/ip6_route.h
index a398ae5..ab29daf 100644
--- a/include/net/ip6_route.h
+++ b/include/net/ip6_route.h
@@ -146,7 +146,7 @@ static inline void ip6_dst_store(struct sock *sk, struct dst_entry *dst,
 	struct rt6_info *rt = (struct rt6_info *) dst;
 
 	write_lock(&sk->sk_dst_lock);
-	__sk_dst_set(sk, dst);
+	sk_setup_caps(sk, dst);
 	np->daddr_cache = daddr;
 	np->dst_cookie = rt->rt6i_node ? rt->rt6i_node->fn_sernum : 0;
 	write_unlock(&sk->sk_dst_lock);
diff --git a/include/net/tcp_ecn.h b/include/net/tcp_ecn.h
index 7bb366f..4629d77 100644
--- a/include/net/tcp_ecn.h
+++ b/include/net/tcp_ecn.h
@@ -55,9 +55,7 @@ static inline void TCP_ECN_send(struct sock *sk, struct tcp_sock *tp,
 			if (tp->ecn_flags&TCP_ECN_QUEUE_CWR) {
 				tp->ecn_flags &= ~TCP_ECN_QUEUE_CWR;
 				skb->h.th->cwr = 1;
-				if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
-					skb_shinfo(skb)->gso_type |=
-						SKB_GSO_TCPV4_ECN;
+				skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
 			}
 		} else {
 			/* ACK or retransmitted segment: clear ECT|CE */