selftests: fcnal: Test SO_DONTROUTE on raw and ping sockets.

Use ping -r to test the kernel behaviour with raw and ping sockets
having the SO_DONTROUTE option.

Since ipv4_ping_novrf() is called with different values of
net.ipv4.ping_group_range, then it tests both raw and ping sockets
(ping uses ping sockets if its user ID belongs to ping_group_range
and raw sockets otherwise).

With both socket types, sending packets to a neighbour (on link) host,
should work. When the host is behind a router, sending should fail.
Signed-off-by: Guillaume Nault <gnault@redhat.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

tools/testing/selftests/net/fcnal-test.sh

@@ -584,6 +584,20 @@ ipv4_ping_novrf()
 		log_test_addr ${a} $? 0 "ping out, address bind"
 	done
 
+	#
+	# out, but don't use gateway if peer is not on link
+	#
+	a=${NSB_IP}
+	log_start
+	run_cmd ping -c 1 -w 1 -r ${a}
+	log_test_addr ${a} $? 0 "ping out (don't route), peer on link"
+
+	a=${NSB_LO_IP}
+	log_start
+	show_hint "Fails since peer is not on link"
+	run_cmd ping -c 1 -w 1 -r ${a}
+	log_test_addr ${a} $? 1 "ping out (don't route), peer not on link"
+
 	#
 	# in
 	#