Tcp.Keepalive
TCP keepalives.
A TCP implementation may send "keep-alives" (empty TCP ACKs with the sequence number set to one less than the current sequence number for the connection) in order to provoke the peer to respond with an ACK of the current sequence number. If the peer doesn't recognise the connection (e.g. because the connection state has been dropped) then it will return a RST; if the peer (or the network in-between) fails to respond to a configured number of repeated probes then the connection is assumed to be lost.
type action = [
| `SendProbe
we should send a keep-alive now
*)| `Wait of Duration.t
sleep for a given number of nanoseconds
*)| `Close
connection should be closed
*) ]
An I/O action to perform
val alive : state
An alive connection
val next :
configuration:Tcpip.Tcp.Keepalive.t ->
ns:int64 ->
state ->
action * state
next ~configuration ~ns state
returns the action we should take given that we last received a packet ns
nanoseconds ago and the new state of the connection