net/smc: respond to test link messages

Add TEST LINK message responses, which also serves as preparation for
support of sockopt TCP_KEEPALIVE.

Signed-off-by: Karsten Graul <kgraul@linux.vnet.ibm.com>
Signed-off-by: Ursula Braun <ubraun@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2 files changed