From b69352245ab729cc01088c8258a3167f069bd684 Mon Sep 17 00:00:00 2001
From: Bhasker Hariharan <bhaskerh@google.com>
Date: Wed, 2 Sep 2020 18:19:50 -0700
Subject: Fix Accept to not return error for sockets in accept queue.

Accept on gVisor will return an error if a socket in the accept queue was closed
before Accept() was called. Linux will return the new fd even if the returned
socket is already closed by the peer say due to a RST being sent by the peer.

This seems to be intentional in linux more details on the github issue.

Fixes #3780

PiperOrigin-RevId: 329828404
---
 pkg/tcpip/transport/packet/endpoint.go | 20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

(limited to 'pkg/tcpip/transport/packet')

diff --git a/pkg/tcpip/transport/packet/endpoint.go b/pkg/tcpip/transport/packet/endpoint.go
index 81093e9ca..8bd4e5e37 100644
--- a/pkg/tcpip/transport/packet/endpoint.go
+++ b/pkg/tcpip/transport/packet/endpoint.go
@@ -192,13 +192,13 @@ func (ep *endpoint) Read(addr *tcpip.FullAddress) (buffer.View, tcpip.ControlMes
 	return ep.ReadPacket(addr, nil)
 }
 
-func (ep *endpoint) Write(p tcpip.Payloader, opts tcpip.WriteOptions) (int64, <-chan struct{}, *tcpip.Error) {
+func (*endpoint) Write(p tcpip.Payloader, opts tcpip.WriteOptions) (int64, <-chan struct{}, *tcpip.Error) {
 	// TODO(gvisor.dev/issue/173): Implement.
 	return 0, nil, tcpip.ErrInvalidOptionValue
 }
 
 // Peek implements tcpip.Endpoint.Peek.
-func (ep *endpoint) Peek([][]byte) (int64, tcpip.ControlMessages, *tcpip.Error) {
+func (*endpoint) Peek([][]byte) (int64, tcpip.ControlMessages, *tcpip.Error) {
 	return 0, tcpip.ControlMessages{}, nil
 }
 
@@ -210,25 +210,25 @@ func (*endpoint) Disconnect() *tcpip.Error {
 
 // Connect implements tcpip.Endpoint.Connect. Packet sockets cannot be
 // connected, and this function always returnes tcpip.ErrNotSupported.
-func (ep *endpoint) Connect(addr tcpip.FullAddress) *tcpip.Error {
+func (*endpoint) Connect(addr tcpip.FullAddress) *tcpip.Error {
 	return tcpip.ErrNotSupported
 }
 
 // Shutdown implements tcpip.Endpoint.Shutdown. Packet sockets cannot be used
 // with Shutdown, and this function always returns tcpip.ErrNotSupported.
-func (ep *endpoint) Shutdown(flags tcpip.ShutdownFlags) *tcpip.Error {
+func (*endpoint) Shutdown(flags tcpip.ShutdownFlags) *tcpip.Error {
 	return tcpip.ErrNotSupported
 }
 
 // Listen implements tcpip.Endpoint.Listen. Packet sockets cannot be used with
 // Listen, and this function always returns tcpip.ErrNotSupported.
-func (ep *endpoint) Listen(backlog int) *tcpip.Error {
+func (*endpoint) Listen(backlog int) *tcpip.Error {
 	return tcpip.ErrNotSupported
 }
 
 // Accept implements tcpip.Endpoint.Accept. Packet sockets cannot be used with
 // Accept, and this function always returns tcpip.ErrNotSupported.
-func (ep *endpoint) Accept() (tcpip.Endpoint, *waiter.Queue, *tcpip.Error) {
+func (*endpoint) Accept(*tcpip.FullAddress) (tcpip.Endpoint, *waiter.Queue, *tcpip.Error) {
 	return nil, nil, tcpip.ErrNotSupported
 }
 
@@ -267,12 +267,12 @@ func (ep *endpoint) Bind(addr tcpip.FullAddress) *tcpip.Error {
 }
 
 // GetLocalAddress implements tcpip.Endpoint.GetLocalAddress.
-func (ep *endpoint) GetLocalAddress() (tcpip.FullAddress, *tcpip.Error) {
+func (*endpoint) GetLocalAddress() (tcpip.FullAddress, *tcpip.Error) {
 	return tcpip.FullAddress{}, tcpip.ErrNotSupported
 }
 
 // GetRemoteAddress implements tcpip.Endpoint.GetRemoteAddress.
-func (ep *endpoint) GetRemoteAddress() (tcpip.FullAddress, *tcpip.Error) {
+func (*endpoint) GetRemoteAddress() (tcpip.FullAddress, *tcpip.Error) {
 	// Even a connected socket doesn't return a remote address.
 	return tcpip.FullAddress{}, tcpip.ErrNotConnected
 }
@@ -371,7 +371,7 @@ func (*endpoint) GetSockOpt(tcpip.GettableSocketOption) *tcpip.Error {
 }
 
 // GetSockOptBool implements tcpip.Endpoint.GetSockOptBool.
-func (ep *endpoint) GetSockOptBool(opt tcpip.SockOptBool) (bool, *tcpip.Error) {
+func (*endpoint) GetSockOptBool(opt tcpip.SockOptBool) (bool, *tcpip.Error) {
 	return false, tcpip.ErrNotSupported
 }
 
@@ -508,7 +508,7 @@ func (ep *endpoint) HandlePacket(nicID tcpip.NICID, localAddr tcpip.LinkAddress,
 }
 
 // State implements socket.Socket.State.
-func (ep *endpoint) State() uint32 {
+func (*endpoint) State() uint32 {
 	return 0
 }
 
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