[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, 9 insertions, 7 deletions

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index fe63d4efbd4d..368d98578c14 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -172,9 +172,9 @@ struct sk_buff *__alloc_skb(unsigned int size, gfp_t gfp_mask,
         shinfo = skb_shinfo(skb);
         atomic_set(&shinfo->dataref, 1);
         shinfo->nr_frags  = 0;
-        shinfo->tso_size = 0;
-        shinfo->tso_segs = 0;
-        shinfo->ufo_size = 0;
+        shinfo->gso_size = 0;
+        shinfo->gso_segs = 0;
+        shinfo->gso_type = 0;
         shinfo->ip6_frag_id = 0;
         shinfo->frag_list = NULL;
 
@@ -238,8 +238,9 @@ struct sk_buff *alloc_skb_from_cache(kmem_cache_t *cp,
 
         atomic_set(&(skb_shinfo(skb)->dataref), 1);
         skb_shinfo(skb)->nr_frags  = 0;
-        skb_shinfo(skb)->tso_size = 0;
-        skb_shinfo(skb)->tso_segs = 0;
+        skb_shinfo(skb)->gso_size = 0;
+        skb_shinfo(skb)->gso_segs = 0;
+        skb_shinfo(skb)->gso_type = 0;
         skb_shinfo(skb)->frag_list = NULL;
 out:
         return skb;
@@ -528,8 +529,9 @@ static void copy_skb_header(struct sk_buff *new, const struct sk_buff *old)
 #endif
         skb_copy_secmark(new, old);
         atomic_set(&new->users, 1);
-        skb_shinfo(new)->tso_size = skb_shinfo(old)->tso_size;
-        skb_shinfo(new)->tso_segs = skb_shinfo(old)->tso_segs;
+        skb_shinfo(new)->gso_size = skb_shinfo(old)->gso_size;
+        skb_shinfo(new)->gso_segs = skb_shinfo(old)->gso_segs;
+        skb_shinfo(new)->gso_type = skb_shinfo(old)->gso_type;
 }
 
 /**