pinctrl: send RST instead of RST_ACK bit for lb hc

Currently an ovn-controller send RST_ACK after receive SYN_ACK in
load balancer health check, but for a windows as load balancer
backend this behavior unexcpected and windows send SYN_ACK like a
tcp retransmission after every RST_ACK, finaly after few reties windows
send RST bit to ovn-controller. In this case the svc_mon status flapping
between online and offline, which triger the ovn-northd for each changes
and increase CPU-usage ovn-northd to 100%.

This patch fixing this behavior for windows and doesn't affect linux with
send RST instead of RST_ACK after received SYN_ACK.

In RFC1122 section 4.2.2.13 described the ways for closing a connection:
https://datatracker.ietf.org/doc/html/rfc1122#page-87
A TCP connection may terminate in two ways: (1) the normal
    TCP close sequence using a FIN handshake, and (2) an "abort"
    in which one or more RST segments are sent and the
    connection state is immediately discarded.
For example, nmap tool use the same logic with RST for scaning ports.

Signed-off-by: Evgenii Kovalev <ekovalev.off@gmail.com>
Acked-by: Mark Michelson <mmichels@redhat.com>
Signed-off-by: Dumitru Ceara <dceara@redhat.com>

controller/pinctrl.c

@@ -7827,7 +7827,6 @@ pinctrl_handle_tcp_svc_check(struct rconn *swconn,
         return false;
     }
 
-    uint32_t tcp_seq = ntohl(get_16aligned_be32(&th->tcp_seq));
     uint32_t tcp_ack = ntohl(get_16aligned_be32(&th->tcp_ack));
 
     if (th->tcp_dst != svc_mon->tp_src) {
@@ -7845,9 +7844,9 @@ pinctrl_handle_tcp_svc_check(struct rconn *swconn,
         svc_mon->state = SVC_MON_S_ONLINE;
 
         /* Send RST-ACK packet. */
-        svc_monitor_send_tcp_health_check__(swconn, svc_mon, TCP_RST | TCP_ACK,
-                                            htonl(tcp_ack + 1),
-                                            htonl(tcp_seq + 1), th->tcp_dst);
+        svc_monitor_send_tcp_health_check__(swconn, svc_mon, TCP_RST,
+                                            htonl(tcp_ack),
+                                            htonl(0), th->tcp_dst);
         /* Calculate next_send_time. */
         svc_mon->next_send_time = time_msec() + svc_mon->interval;
         return true;