From 12c256568ba784c07cf73822359faac2971e8306 Mon Sep 17 00:00:00 2001
From: Tamir Duberstein <tamird@google.com>
Date: Tue, 23 Jul 2019 12:09:15 -0700
Subject: Deduplicate EndpointState.connected some

This fixes a bug introduced in cl/251934850 that caused
connect-accept-close-connect races to result in the second connect call
failiing when it should have succeeded.

PiperOrigin-RevId: 259584525
---
 pkg/tcpip/transport/tcp/endpoint.go       | 24 +++++++++++++-----------
 pkg/tcpip/transport/tcp/endpoint_state.go |  7 +++++--
 2 files changed, 18 insertions(+), 13 deletions(-)

(limited to 'pkg/tcpip')

diff --git a/pkg/tcpip/transport/tcp/endpoint.go b/pkg/tcpip/transport/tcp/endpoint.go
index 89154391b..cc49c8272 100644
--- a/pkg/tcpip/transport/tcp/endpoint.go
+++ b/pkg/tcpip/transport/tcp/endpoint.go
@@ -489,8 +489,8 @@ func (e *endpoint) Readiness(mask waiter.EventMask) waiter.EventMask {
 				result |= waiter.EventIn
 			}
 		}
-
-	case StateEstablished, StateFinWait1, StateFinWait2, StateTimeWait, StateCloseWait, StateLastAck, StateClosing:
+	}
+	if e.state.connected() {
 		// Determine if the endpoint is writable if requested.
 		if (mask & waiter.EventOut) != 0 {
 			e.sndBufMu.Lock()
@@ -1323,6 +1323,17 @@ func (e *endpoint) connect(addr tcpip.FullAddress, handshake bool, run bool) (er
 		return err
 	}
 
+	if e.state.connected() {
+		// The endpoint is already connected. If caller hasn't been
+		// notified yet, return success.
+		if !e.isConnectNotified {
+			e.isConnectNotified = true
+			return nil
+		}
+		// Otherwise return that it's already connected.
+		return tcpip.ErrAlreadyConnected
+	}
+
 	nicid := addr.NIC
 	switch e.state {
 	case StateBound:
@@ -1347,15 +1358,6 @@ func (e *endpoint) connect(addr tcpip.FullAddress, handshake bool, run bool) (er
 		// yet.
 		return tcpip.ErrAlreadyConnecting
 
-	case StateEstablished:
-		// The endpoint is already connected. If caller hasn't been notified yet, return success.
-		if !e.isConnectNotified {
-			e.isConnectNotified = true
-			return nil
-		}
-		// Otherwise return that it's already connected.
-		return tcpip.ErrAlreadyConnected
-
 	case StateError:
 		return e.hardError
 
diff --git a/pkg/tcpip/transport/tcp/endpoint_state.go b/pkg/tcpip/transport/tcp/endpoint_state.go
index b93959034..b3f0f6c5d 100644
--- a/pkg/tcpip/transport/tcp/endpoint_state.go
+++ b/pkg/tcpip/transport/tcp/endpoint_state.go
@@ -50,6 +50,8 @@ func (e *endpoint) beforeSave() {
 
 	switch e.state {
 	case StateInitial, StateBound:
+		// TODO(b/138137272): this enumeration duplicates
+		// EndpointState.connected. remove it.
 	case StateEstablished, StateSynSent, StateSynRecv, StateFinWait1, StateFinWait2, StateTimeWait, StateCloseWait, StateLastAck, StateClosing:
 		if e.route.Capabilities()&stack.CapabilitySaveRestore == 0 {
 			if e.route.Capabilities()&stack.CapabilityDisconnectOk == 0 {
@@ -149,9 +151,10 @@ var connectingLoading sync.WaitGroup
 func (e *endpoint) loadState(state EndpointState) {
 	// This is to ensure that the loading wait groups include all applicable
 	// endpoints before any asynchronous calls to the Wait() methods.
-	switch state {
-	case StateEstablished, StateFinWait1, StateFinWait2, StateTimeWait, StateCloseWait, StateLastAck, StateClosing:
+	if state.connected() {
 		connectedLoading.Add(1)
+	}
+	switch state {
 	case StateListen:
 		listenLoading.Add(1)
 	case StateConnecting, StateSynSent, StateSynRecv:
-- 
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