net: introduce keepalive function in struct proto

Direct call of tcp_set_keepalive() function from protocol-agnostic
sock_setsockopt() function in net/core/sock.c violates network
layering. And newly introduced protocol (SMC-R) will need its own
keepalive function. Therefore, add "keepalive" function pointer
to "struct proto", and call it from sock_setsockopt() via this pointer.

Signed-off-by: Ursula Braun <ubraun@linux.vnet.ibm.com>
Reviewed-by: Utz Bacher <utz.bacher@de.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/sock.h b/include/net/sock.h
index f0e867f..99deda6 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -1024,6 +1024,7 @@
 	int			(*getsockopt)(struct sock *sk, int level,
 					int optname, char __user *optval,
 					int __user *option);
+	void			(*keepalive)(struct sock *sk, int valbool);
 #ifdef CONFIG_COMPAT
 	int			(*compat_setsockopt)(struct sock *sk,
 					int level,