Remove PauseTx and PauseRx of the reverse proxy from the e2e test

Part of the patches to fix #17737

During the development of #17938,
we agreed that during the transition to L7 forward proxy, unused
features and features targeting L4 reverse proxy will be dropped.

This feature falls under the unused feature.

Signed-off-by: Chun-Hung Tseng <henrybear327@gmail.com>

Author: henrybear327

pkg/proxy/server.go

@@ -146,12 +146,6 @@ type server struct {
 	modifyRxMu sync.RWMutex
 	modifyRx   func(data []byte) []byte
 
-	pauseTxMu sync.Mutex
-	pauseTxc  chan struct{}
-
-	pauseRxMu sync.Mutex
-	pauseRxc  chan struct{}
-
 	latencyTxMu sync.RWMutex
 	latencyTx   time.Duration
 
@@ -177,9 +171,6 @@ func NewServer(cfg ServerConfig) Server {
 		readyc: make(chan struct{}),
 		donec:  make(chan struct{}),
 		errc:   make(chan error, 16),
-
-		pauseTxc: make(chan struct{}),
-		pauseRxc: make(chan struct{}),
 	}
 
 	_, fromPort, err := net.SplitHostPort(cfg.From.Host)
@@ -202,9 +193,6 @@ func NewServer(cfg ServerConfig) Server {
 		s.retryInterval = defaultRetryInterval
 	}
 
-	close(s.pauseTxc)
-	close(s.pauseRxc)
-
 	if strings.HasPrefix(s.from.Scheme, "http") {
 		s.from.Scheme = "tcp"
 	}
@@ -443,27 +431,6 @@ func (s *server) ioCopy(dst io.Writer, src io.Reader, ptype proxyType) {
 			panic("unknown proxy type")
 		}
 
-		// pause before packet dropping, blocking, and forwarding
-		var pausec chan struct{}
-		switch ptype {
-		case proxyTx:
-			s.pauseTxMu.Lock()
-			pausec = s.pauseTxc
-			s.pauseTxMu.Unlock()
-		case proxyRx:
-			s.pauseRxMu.Lock()
-			pausec = s.pauseRxc
-			s.pauseRxMu.Unlock()
-		default:
-			panic("unknown proxy type")
-		}
-		select {
-		case <-pausec:
-		case <-s.donec:
-			return
-		}
-
-		// pause first, and then drop packets
 		if nr2 == 0 {
 			continue
 		}
@@ -774,68 +741,6 @@ func (s *server) UnblackholeRx() {
 	)
 }
 
-func (s *server) PauseTx() {
-	s.pauseTxMu.Lock()
-	s.pauseTxc = make(chan struct{})
-	s.pauseTxMu.Unlock()
-
-	s.lg.Info(
-		"paused tx",
-		zap.String("from", s.From()),
-		zap.String("to", s.To()),
-	)
-}
-
-func (s *server) UnpauseTx() {
-	s.pauseTxMu.Lock()
-	select {
-	case <-s.pauseTxc: // already unpaused
-	case <-s.donec:
-		s.pauseTxMu.Unlock()
-		return
-	default:
-		close(s.pauseTxc)
-	}
-	s.pauseTxMu.Unlock()
-
-	s.lg.Info(
-		"unpaused tx",
-		zap.String("from", s.From()),
-		zap.String("to", s.To()),
-	)
-}
-
-func (s *server) PauseRx() {
-	s.pauseRxMu.Lock()
-	s.pauseRxc = make(chan struct{})
-	s.pauseRxMu.Unlock()
-
-	s.lg.Info(
-		"paused rx",
-		zap.String("from", s.To()),
-		zap.String("to", s.From()),
-	)
-}
-
-func (s *server) UnpauseRx() {
-	s.pauseRxMu.Lock()
-	select {
-	case <-s.pauseRxc: // already unpaused
-	case <-s.donec:
-		s.pauseRxMu.Unlock()
-		return
-	default:
-		close(s.pauseRxc)
-	}
-	s.pauseRxMu.Unlock()
-
-	s.lg.Info(
-		"unpaused rx",
-		zap.String("from", s.To()),
-		zap.String("to", s.From()),
-	)
-}
-
 func (s *server) ResetListener() error {
 	s.listenerMu.Lock()
 	defer s.listenerMu.Unlock()