Merge release-20200608.0-61-g67f261a87 (automated)

2 files changed, 31 insertions, 29 deletions

diff --git a/pkg/tcpip/transport/tcp/accept.go b/pkg/tcpip/transport/tcp/accept.go
index ad197e8db..7679fe169 100644
--- a/pkg/tcpip/transport/tcp/accept.go
+++ b/pkg/tcpip/transport/tcp/accept.go
@@ -222,12 +222,6 @@ func (l *listenContext) createConnectingEndpoint(s *segment, iss seqnum.Value, i
 
 	n.initGSO()
 
-	// Create sender and receiver.
-	//
-	// The receiver at least temporarily has a zero receive window scale,
-	// but the caller may change it (before starting the protocol loop).
-	n.snd = newSender(n, iss, irs, s.window, rcvdSynOpts.MSS, rcvdSynOpts.WS)
-	n.rcv = newReceiver(n, irs, seqnum.Size(n.initialReceiveWindow()), 0, seqnum.Size(n.receiveBufferSize()))
 	// Bootstrap the auto tuning algorithm. Starting at zero will result in
 	// a large step function on the first window adjustment causing the
 	// window to grow to a really large value.
@@ -295,7 +289,7 @@ func (l *listenContext) createEndpointAndPerformHandshake(s *segment, opts *head
 	}
 
 	// Perform the 3-way handshake.
-	h := newPassiveHandshake(ep, ep.rcv.rcvWnd, isn, irs, opts, deferAccept)
+	h := newPassiveHandshake(ep, seqnum.Size(ep.initialReceiveWindow()), isn, irs, opts, deferAccept)
 	if err := h.execute(); err != nil {
 		ep.mu.Unlock()
 		ep.Close()
@@ -536,6 +530,9 @@ func (e *endpoint) handleListenSegment(ctx *listenContext, s *segment) {
 			return
 		}
 
+		iss := s.ackNumber - 1
+		irs := s.sequenceNumber - 1
+
 		// Since SYN cookies are in use this is potentially an ACK to a
 		// SYN-ACK we sent but don't have a half open connection state
 		// as cookies are being used to protect against a potential SYN
@@ -546,7 +543,7 @@ func (e *endpoint) handleListenSegment(ctx *listenContext, s *segment) {
 		// when under a potential syn flood attack.
 		//
 		// Validate the cookie.
-		data, ok := ctx.isCookieValid(s.id, s.ackNumber-1, s.sequenceNumber-1)
+		data, ok := ctx.isCookieValid(s.id, iss, irs)
 		if !ok || int(data) >= len(mssTable) {
 			e.stack.Stats().TCP.ListenOverflowInvalidSynCookieRcvd.Increment()
 			e.stack.Stats().DroppedPackets.Increment()
@@ -571,7 +568,7 @@ func (e *endpoint) handleListenSegment(ctx *listenContext, s *segment) {
 			rcvdSynOptions.TSEcr = s.parsedOptions.TSEcr
 		}
 
-		n, err := ctx.createConnectingEndpoint(s, s.ackNumber-1, s.sequenceNumber-1, rcvdSynOptions, &waiter.Queue{})
+		n, err := ctx.createConnectingEndpoint(s, iss, irs, rcvdSynOptions, &waiter.Queue{})
 		if err != nil {
 			e.stack.Stats().TCP.FailedConnectionAttempts.Increment()
 			e.stats.FailedConnectionAttempts.Increment()
@@ -589,10 +586,17 @@ func (e *endpoint) handleListenSegment(ctx *listenContext, s *segment) {
 		n.tsOffset = 0
 
 		// Switch state to connected.
-		// We do not use transitionToStateEstablishedLocked here as there is
-		// no handshake state available when doing a SYN cookie based accept.
 		n.isConnectNotified = true
-		n.setEndpointState(StateEstablished)
+		n.transitionToStateEstablishedLocked(&handshake{
+			ep:          n,
+			iss:         iss,
+			ackNum:      irs + 1,
+			rcvWnd:      seqnum.Size(n.initialReceiveWindow()),
+			sndWnd:      s.window,
+			rcvWndScale: e.rcvWndScaleForHandshake(),
+			sndWndScale: rcvdSynOptions.WS,
+			mss:         rcvdSynOptions.MSS,
+		})
 
 		// Do the delivery in a separate goroutine so
 		// that we don't block the listen loop in case
diff --git a/pkg/tcpip/transport/tcp/connect.go b/pkg/tcpip/transport/tcp/connect.go
index 7da93dcc4..91ee3b0be 100644
--- a/pkg/tcpip/transport/tcp/connect.go
+++ b/pkg/tcpip/transport/tcp/connect.go
@@ -995,24 +995,22 @@ func (e *endpoint) completeWorkerLocked() {
 
 // transitionToStateEstablisedLocked transitions a given endpoint
 // to an established state using the handshake parameters provided.
-// It also initializes sender/receiver if required.
+// It also initializes sender/receiver.
 func (e *endpoint) transitionToStateEstablishedLocked(h *handshake) {
-	if e.snd == nil {
-		// Transfer handshake state to TCP connection. We disable
-		// receive window scaling if the peer doesn't support it
-		// (indicated by a negative send window scale).
-		e.snd = newSender(e, h.iss, h.ackNum-1, h.sndWnd, h.mss, h.sndWndScale)
-	}
-	if e.rcv == nil {
-		rcvBufSize := seqnum.Size(e.receiveBufferSize())
-		e.rcvListMu.Lock()
-		e.rcv = newReceiver(e, h.ackNum-1, h.rcvWnd, h.effectiveRcvWndScale(), rcvBufSize)
-		// Bootstrap the auto tuning algorithm. Starting at zero will
-		// result in a really large receive window after the first auto
-		// tuning adjustment.
-		e.rcvAutoParams.prevCopied = int(h.rcvWnd)
-		e.rcvListMu.Unlock()
-	}
+	// Transfer handshake state to TCP connection. We disable
+	// receive window scaling if the peer doesn't support it
+	// (indicated by a negative send window scale).
+	e.snd = newSender(e, h.iss, h.ackNum-1, h.sndWnd, h.mss, h.sndWndScale)
+
+	rcvBufSize := seqnum.Size(e.receiveBufferSize())
+	e.rcvListMu.Lock()
+	e.rcv = newReceiver(e, h.ackNum-1, h.rcvWnd, h.effectiveRcvWndScale(), rcvBufSize)
+	// Bootstrap the auto tuning algorithm. Starting at zero will
+	// result in a really large receive window after the first auto
+	// tuning adjustment.
+	e.rcvAutoParams.prevCopied = int(h.rcvWnd)
+	e.rcvListMu.Unlock()
+
 	e.setEndpointState(StateEstablished)
 }