[NET]: Generalise TSO-specific bits from skb_setup_caps

This patch generalises the TSO-specific bits from sk_setup_caps by adding
the sk_gso_type member to struct sock.  This makes sk_setup_caps generic
so that it can be used by TCPv6 or UFO.

The only catch is that whoever uses this must provide a GSO implementation
for their protocol which I think is a fair deal :) For now UFO continues to
live without a GSO implementation which is OK since it doesn't use the sock
caps field at the moment.

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

3 files changed, 20 insertions, 7 deletions

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index aa2d3c12c4d..6db03ab7cec 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -313,6 +313,7 @@ struct net_device
 
         /* Segmentation offload features */
 #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_GSO_ROBUST      (SKB_GSO_DODGY << NETIF_F_GSO_SHIFT)
@@ -991,13 +992,18 @@ extern void dev_seq_stop(struct seq_file *seq, void *v);
 
 extern void linkwatch_run_queue(void);
 
-static inline int skb_gso_ok(struct sk_buff *skb, int features)
+static inline int net_gso_ok(int features, int gso_type)
 {
-        int feature = skb_shinfo(skb)->gso_size ?
-                      skb_shinfo(skb)->gso_type << NETIF_F_GSO_SHIFT : 0;
+        int feature = gso_type << NETIF_F_GSO_SHIFT;
         return (features & feature) == feature;
 }
 
+static inline int skb_gso_ok(struct sk_buff *skb, int features)
+{
+        return net_gso_ok(features, skb_shinfo(skb)->gso_size ?
+                                    skb_shinfo(skb)->gso_type : 0);
+}
+
 static inline int netif_needs_gso(struct net_device *dev, struct sk_buff *skb)
 {
         return !skb_gso_ok(skb, dev->features);
diff --git a/include/net/sock.h b/include/net/sock.h
index 7136bae48c2..7b3d6b85694 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -140,6 +140,7 @@ struct sock_common {
   *     @sk_flags: %SO_LINGER (l_onoff), %SO_BROADCAST, %SO_KEEPALIVE, %SO_OOBINLINE settings
   *     @sk_no_check: %SO_NO_CHECK setting, wether or not checkup packets
   *     @sk_route_caps: route capabilities (e.g. %NETIF_F_TSO)
+  *     @sk_gso_type: GSO type (e.g. %SKB_GSO_TCPV4)
   *     @sk_lingertime: %SO_LINGER l_linger setting
   *     @sk_backlog: always used with the per-socket spinlock held
   *     @sk_callback_lock: used with the callbacks in the end of this struct
@@ -211,6 +212,7 @@ struct sock {
         gfp_t                   sk_allocation;
         int                     sk_sndbuf;
         int                     sk_route_caps;
+        int                     sk_gso_type;
         int                     sk_rcvlowat;
         unsigned long           sk_flags;
         unsigned long           sk_lingertime;
@@ -1025,15 +1027,20 @@ extern struct dst_entry *__sk_dst_check(struct sock *sk, u32 cookie);
 
 extern struct dst_entry *sk_dst_check(struct sock *sk, u32 cookie);
 
+static inline int sk_can_gso(const struct sock *sk)
+{
+        return net_gso_ok(sk->sk_route_caps, sk->sk_gso_type);
+}
+
 static inline void sk_setup_caps(struct sock *sk, struct dst_entry *dst)
 {
         __sk_dst_set(sk, dst);
         sk->sk_route_caps = dst->dev->features;
         if (sk->sk_route_caps & NETIF_F_GSO)
-                sk->sk_route_caps |= NETIF_F_TSO;
-        if (sk->sk_route_caps & NETIF_F_TSO) {
+                sk->sk_route_caps |= NETIF_F_GSO_MASK;
+        if (sk_can_gso(sk)) {
                 if (dst->header_len)
-                        sk->sk_route_caps &= ~NETIF_F_TSO;
+                        sk->sk_route_caps &= ~NETIF_F_GSO_MASK;
                 else 
                         sk->sk_route_caps |= NETIF_F_SG | NETIF_F_HW_CSUM;
         }
diff --git a/include/net/tcp.h b/include/net/tcp.h
index 624921e7633..3cd803b0d7a 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -751,7 +751,7 @@ static inline int tcp_is_cwnd_limited(const struct sock *sk, u32 in_flight)
         if (in_flight >= tp->snd_cwnd)
                 return 1;
 
-        if (!(sk->sk_route_caps & NETIF_F_TSO))
+        if (!sk_can_gso(sk))
                 return 0;
 
         left = tp->snd_cwnd - in_flight;