ipv4: add a sock pointer to dst->output() path.

In the dst->output() path for ipv4, the code assumes the skb it has to
transmit is attached to an inet socket, specifically via
ip_mc_output() : The sk_mc_loop() test triggers a WARN_ON() when the
provider of the packet is an AF_PACKET socket.

The dst->output() method gets an additional 'struct sock *sk'
parameter. This needs a cascade of changes so that this parameter can
be propagated from vxlan to final consumer.

Fixes: 8f646c922d55 ("vxlan: keep original skb ownership")
Reported-by: lucien xin <lucien.xin@gmail.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/ip.h b/include/net/ip.h
index 77e73d2..3ec2b0f 100644
--- a/include/net/ip.h
+++ b/include/net/ip.h
@@ -104,13 +104,18 @@
 	   struct net_device *orig_dev);
 int ip_local_deliver(struct sk_buff *skb);
 int ip_mr_input(struct sk_buff *skb);
-int ip_output(struct sk_buff *skb);
-int ip_mc_output(struct sk_buff *skb);
+int ip_output(struct sock *sk, struct sk_buff *skb);
+int ip_mc_output(struct sock *sk, struct sk_buff *skb);
 int ip_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *));
 int ip_do_nat(struct sk_buff *skb);
 void ip_send_check(struct iphdr *ip);
 int __ip_local_out(struct sk_buff *skb);
-int ip_local_out(struct sk_buff *skb);
+int ip_local_out_sk(struct sock *sk, struct sk_buff *skb);
+static inline int ip_local_out(struct sk_buff *skb)
+{
+	return ip_local_out_sk(skb->sk, skb);
+}
+
 int ip_queue_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl);
 void ip_init(void);
 int ip_append_data(struct sock *sk, struct flowi4 *fl4,