net: Add Software fallback infrastructure for socket dependent offloads

With socket dependent offloads we rely on the netdev to transform
the transmitted packets before sending them to the wire.
When a packet from an offloaded socket is rerouted to a different
device we need to detect it and do the transformation in software.

Signed-off-by: Ilya Lesokhin <ilyal@mellanox.com>
Signed-off-by: Boris Pismenny <borisp@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 21 insertions, 0 deletions

diff --git a/include/net/sock.h b/include/net/sock.h
index 74d725fdbe0f..3c568b36ee36 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -481,6 +481,11 @@ struct sock {
         void                    (*sk_error_report)(struct sock *sk);
         int                     (*sk_backlog_rcv)(struct sock *sk,
                                                   struct sk_buff *skb);
+#ifdef CONFIG_SOCK_VALIDATE_XMIT
+        struct sk_buff*         (*sk_validate_xmit_skb)(struct sock *sk,
+                                                        struct net_device *dev,
+                                                        struct sk_buff *skb);
+#endif
         void                    (*sk_destruct)(struct sock *sk);
         struct sock_reuseport __rcu     *sk_reuseport_cb;
         struct rcu_head         sk_rcu;
@@ -2332,6 +2337,22 @@ static inline bool sk_fullsock(const struct sock *sk)
         return (1 << sk->sk_state) & ~(TCPF_TIME_WAIT | TCPF_NEW_SYN_RECV);
 }
 
+/* Checks if this SKB belongs to an HW offloaded socket
+ * and whether any SW fallbacks are required based on dev.
+ */
+static inline struct sk_buff *sk_validate_xmit_skb(struct sk_buff *skb,
+                                                   struct net_device *dev)
+{
+#ifdef CONFIG_SOCK_VALIDATE_XMIT
+        struct sock *sk = skb->sk;
+
+        if (sk && sk_fullsock(sk) && sk->sk_validate_xmit_skb)
+                skb = sk->sk_validate_xmit_skb(sk, dev, skb);
+#endif
+
+        return skb;
+}
+
 /* This helper checks if a socket is a LISTEN or NEW_SYN_RECV
  * SYNACK messages can be attached to either ones (depending on SYNCOOKIE)
  */