[NET]: Merge TSO/UFO fields in sk_buff

Having separate fields in sk_buff for TSO/UFO (tso_size/ufo_size) is not
going to scale if we add any more segmentation methods (e.g., DCCP).  So
let's merge them.

They were used to tell the protocol of a packet.  This function has been
subsumed by the new gso_type field.  This is essentially a set of netdev
feature bits (shifted by 16 bits) that are required to process a specific
skb.  As such it's easy to tell whether a given device can process a GSO
skb: you just have to and the gso_type field and the netdev's features
field.

I've made gso_type a conjunction.  The idea is that you have a base type
(e.g., SKB_GSO_TCPV4) that can be modified further to support new features.
For example, if we add a hardware TSO type that supports ECN, they would
declare NETIF_F_TSO | NETIF_F_TSO_ECN.  All TSO packets with CWR set would
have a gso_type of SKB_GSO_TCPV4 | SKB_GSO_TCPV4_ECN while all other TSO
packets would be SKB_GSO_TCPV4.  This means that only the CWR packets need
to be emulated in software.

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

1 files changed, 4 insertions, 3 deletions

diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index d29620f4910e..abb94de33768 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -148,7 +148,7 @@ static int ip6_output2(struct sk_buff *skb)
 
 int ip6_output(struct sk_buff *skb)
 {
-        if ((skb->len > dst_mtu(skb->dst) && !skb_shinfo(skb)->ufo_size) ||
+        if ((skb->len > dst_mtu(skb->dst) && !skb_shinfo(skb)->gso_size) ||
                                 dst_allfrag(skb->dst))
                 return ip6_fragment(skb, ip6_output2);
         else
@@ -833,8 +833,9 @@ static inline int ip6_ufo_append_data(struct sock *sk,
                 struct frag_hdr fhdr;
 
                 /* specify the length of each IP datagram fragment*/
-                skb_shinfo(skb)->ufo_size = (mtu - fragheaderlen) - 
-                                                sizeof(struct frag_hdr);
+                skb_shinfo(skb)->gso_size = mtu - fragheaderlen - 
+                                            sizeof(struct frag_hdr);
+                skb_shinfo(skb)->gso_type = SKB_GSO_UDPV4;
                 ipv6_select_ident(skb, &fhdr);
                 skb_shinfo(skb)->ip6_frag_id = fhdr.identification;
                 __skb_queue_tail(&sk->sk_write_queue, skb);