// Performs handling of all Change Request Protocol messages,
// over all connections. Has exclusive access to forward timeout information,
// and uses requestTimeoutLock for access to request timeout information.
// Top-level function of the processing goroutine.
func process() {
for {
select {
// Requesting Change Request Timeout
case timeout := <-requestTimedOut:
requestTimeoutLock.Lock()
if timeout.canceled {
break
}
log.Print("shared/chrequest: request timeout: ",
*timeout.request.RequestId)
// Remove this request timeout.
cancelRequestTimeout(
uint16(*timeout.request.RequestNode),
*timeout.request.RequestId)
// Request the change again, with double the timeout.
addRequestTimeout(timeout.request, timeout.duration*2)
requestTimeoutLock.Unlock()
forward := new(chproto.ChangeForward)
forward.Request = timeout.request
processForward(forward)
// Forwarded Change Forward Timeout
case timeout := <-forwardTimedOut:
if timeout.canceled {
break
}
// Remove this forward timeout.
cancelForwardTimeout(
uint16(*timeout.forward.Request.RequestNode),
*timeout.forward.Request.RequestId)
// Try sending it somewhere else.
processForward(timeout.forward)
// New Change Request
case newRequest := <-newRequestCh:
requestTimeoutLock.Lock()
addRequestTimeout(newRequest,
config.CHANGE_TIMEOUT_PERIOD)
requestTimeoutLock.Unlock()
forward := new(chproto.ChangeForward)
forward.Request = newRequest
processForward(forward)
// Received Change Forward Message
case receivedForward := <-receivedForwardCh:
processForward(receivedForward.forward)
// Received Change Forward Ack Message
case receivedAck := <-receivedAckCh:
ack := receivedAck.ack
// If we did not have a forwarded change forward,
// with this requesting node and request ID,
// and this node as the last node it was sent to,
// discard the message.
timeout, exists := getForwardTimeout(
uint16(*ack.RequestNode),
*ack.RequestId)
if !exists {
break
}
ignores := timeout.forward.Ignores
if uint16(ignores[len(ignores)-1]) != receivedAck.node {
break
}
// Remove this forward timeout.
cancelForwardTimeout(
uint16(*timeout.forward.Request.RequestNode),
*timeout.forward.Request.RequestId)
// Connection Terminated
case terminatedConn := <-terminatedConnCh:
node := terminatedConn.node
conn := terminatedConn.conn
// Remove this connection from our connection list.
index := -1
for i, _ := range connections[node] {
if conn == connections[node][i] {
index = i
break
}
}
if index == -1 {
break
}
connections[node] = append(connections[node][:index],
connections[node][index+1:]...)
// Connection Received
case receivedConn := <-receivedConnCh:
node := receivedConn.node
conn := receivedConn.conn
// Add to our connections list.
connections[node] = append(connections[node], conn)
}
}
}
