teamd: lw: arp_ping: only check arp reply message

Currently we check both arp request and reply message for arp_ping link
watch. But if we enabled validate_active and validate_inactive at the
same time, we will receive the other slave's arp request as the switch
broadcasts arp request message. i.e. slave1 receives arp request from
slave2 and vice versa.

Then the arp check will pass even the target is unreachable. Fix it by
only check arp reply message.

Reported-by: LiLiang <liali@redhat.com>
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
diff --git a/teamd/teamd_lw_arp_ping.c b/teamd/teamd_lw_arp_ping.c
index 01cd6e1..81806f0 100644
--- a/teamd/teamd_lw_arp_ping.c
+++ b/teamd/teamd_lw_arp_ping.c
@@ -336,7 +336,8 @@
 		if (ap.ah.ar_hrd != htons(ll_my.sll_hatype) ||
 		    ap.ah.ar_pro != htons(ETH_P_IP) ||
 		    ap.ah.ar_hln != ll_my.sll_halen ||
-		    ap.ah.ar_pln != 4) {
+		    ap.ah.ar_pln != 4 ||
+		    ap.ah.ar_op != htons(ARPOP_REPLY)) {
 			return 0;
 		}