fsm: Lower minimal ConnectRetry interval to 1s

Lower the minConnectRetryInterval from 5s to 1s.
As this interval also defines the wait time before
the initial connection attempt, lowering it helps
in situations where fast re(connection) times
are required.

The change also allows for wider variation for the
random jitter applied for the ConnectRetry timer.

Signed-off-by: Rastislav Szabo <[email protected]>

Author: rastislavs

pkg/server/fsm.go

@@ -37,7 +37,7 @@ import (
 )
 
 const (
-	minConnectRetryInterval = 5
+	minConnectRetryInterval = 1
 )
 
 type fsmStateReasonType uint8
@@ -494,7 +494,7 @@ func (h *fsmHandler) connectLoop(ctx context.Context, wg *sync.WaitGroup) {
 	defer wg.Done()
 	fsm := h.fsm
 
-	retry, addr, port, password, ttl, ttlMin, mss, localAddress, localPort, bindInterface := func() (int, string, int, string, uint8, uint8, uint16, string, int, string) {
+	retryInterval, addr, port, password, ttl, ttlMin, mss, localAddress, localPort, bindInterface := func() (int, string, int, string, uint8, uint8, uint16, string, int, string) {
 		fsm.lock.RLock()
 		defer fsm.lock.RUnlock()
 
@@ -527,7 +527,7 @@ func (h *fsmHandler) connectLoop(ctx context.Context, wg *sync.WaitGroup) {
 	tick := minConnectRetryInterval
 	for {
 		r := rand.New(rand.NewSource(time.Now().UnixNano()))
-		timer := time.NewTimer(time.Duration(r.Intn(tick)+tick) * time.Second)
+		timer := time.NewTimer(time.Duration(r.Intn(tick*1000)+tick*1000) * time.Millisecond)
 		select {
 		case <-ctx.Done():
 			fsm.logger.Debug("stop connect loop",
@@ -556,7 +556,7 @@ func (h *fsmHandler) connectLoop(ctx context.Context, wg *sync.WaitGroup) {
 		if err == nil {
 			d := net.Dialer{
 				LocalAddr: laddr,
-				Timeout:   time.Duration(tick-1) * time.Second,
+				Timeout:   time.Duration(max(retryInterval-1, minConnectRetryInterval)) * time.Second,
 				Control: func(network, address string, c syscall.RawConn) error {
 					return dialerControl(fsm.logger, network, address, c, ttl, ttlMin, mss, password, bindInterface)
 				},
@@ -594,7 +594,7 @@ func (h *fsmHandler) connectLoop(ctx context.Context, wg *sync.WaitGroup) {
 				}
 			}
 		}
-		tick = retry
+		tick = retryInterval
 	}
 }