[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, 4 insertions, 10 deletions

diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c
index e19457f..0f26073 100644
--- a/net/ipv6/af_inet6.c
+++ b/net/ipv6/af_inet6.c
@@ -660,8 +660,6 @@ int inet6_sk_rebuild_header(struct sock *sk)
 		}
 
 		ip6_dst_store(sk, dst, NULL);
-		sk->sk_route_caps = dst->dev->features &
-			~(NETIF_F_IP_CSUM | NETIF_F_TSO);
 	}
 
 	return 0;
diff --git a/net/ipv6/inet6_connection_sock.c b/net/ipv6/inet6_connection_sock.c
index eb2865d..5624f373 100644
--- a/net/ipv6/inet6_connection_sock.c
+++ b/net/ipv6/inet6_connection_sock.c
@@ -187,8 +187,6 @@ int inet6_csk_xmit(struct sk_buff *skb, int ipfragok)
 		}
 
 		ip6_dst_store(sk, dst, NULL);
-		sk->sk_route_caps = dst->dev->features &
-			~(NETIF_F_IP_CSUM | NETIF_F_TSO);
 	}
 
 	skb->dst = dst_clone(dst);
diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index abb94de..11007c7 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -230,7 +230,7 @@ int ip6_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl,
 	skb->priority = sk->sk_priority;
 
 	mtu = dst_mtu(dst);
-	if ((skb->len <= mtu) || ipfragok) {
+	if ((skb->len <= mtu) || ipfragok || skb_shinfo(skb)->gso_size) {
 		IP6_INC_STATS(IPSTATS_MIB_OUTREQUESTS);
 		return NF_HOOK(PF_INET6, NF_IP6_LOCAL_OUT, skb, NULL, dst->dev,
 				dst_output);
@@ -835,7 +835,7 @@ static inline int ip6_ufo_append_data(struct sock *sk,
 		/* specify the length of each IP datagram fragment*/
 		skb_shinfo(skb)->gso_size = mtu - fragheaderlen - 
 					    sizeof(struct frag_hdr);
-		skb_shinfo(skb)->gso_type = SKB_GSO_UDPV4;
+		skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
 		ipv6_select_ident(skb, &fhdr);
 		skb_shinfo(skb)->ip6_frag_id = fhdr.identification;
 		__skb_queue_tail(&sk->sk_write_queue, skb);
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index bf7f8c2..7ea5bea 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -270,9 +270,8 @@ static int tcp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
 	ipv6_addr_copy(&np->saddr, saddr);
 	inet->rcv_saddr = LOOPBACK4_IPV6;
 
+	sk->sk_gso_type = SKB_GSO_TCPV6;
 	ip6_dst_store(sk, dst, NULL);
-	sk->sk_route_caps = dst->dev->features &
-		~(NETIF_F_IP_CSUM | NETIF_F_TSO);
 
 	icsk->icsk_ext_hdr_len = 0;
 	if (np->opt)
@@ -930,9 +929,8 @@ static struct sock * tcp_v6_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
 	 * comment in that function for the gory details. -acme
 	 */
 
+	sk->sk_gso_type = SKB_GSO_TCPV6;
 	ip6_dst_store(newsk, dst, NULL);
-	newsk->sk_route_caps = dst->dev->features &
-		~(NETIF_F_IP_CSUM | NETIF_F_TSO);
 
 	newtcp6sk = (struct tcp6_sock *)newsk;
 	inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;