From 5d449c870622f7088825af5650786e8bb755567a Mon Sep 17 00:00:00 2001 From: Ghanan Gowripalan Date: Thu, 27 Aug 2020 12:48:19 -0700 Subject: Add function to get error from a tcpip.Endpoint In an upcoming CL, socket option types are made to implement a marker interface with pointer receivers. Since this results in calling methods of an interface with a pointer, we incur an allocation when attempting to get an Endpoint's last error with the current implementation. When calling the method of an interface, the compiler is unable to determine what the interface implementation does with the pointer (since calling a method on an interface uses virtual dispatch at runtime so the compiler does not know what the interface method will do) so it allocates on the heap to be safe incase an implementation continues to hold the pointer after the functioon returns (the reference escapes the scope of the object). In the example below, the compiler does not know what b.foo does with the reference to a it allocates a on the heap as the reference to a may escape the scope of a. ``` var a int var b someInterface b.foo(&a) ``` This change removes the opportunity for that allocation. RELNOTES: n/a PiperOrigin-RevId: 328796559 --- pkg/tcpip/tcpip.go | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) (limited to 'pkg/tcpip/tcpip.go') diff --git a/pkg/tcpip/tcpip.go b/pkg/tcpip/tcpip.go index 609b8af33..cae943608 100644 --- a/pkg/tcpip/tcpip.go +++ b/pkg/tcpip/tcpip.go @@ -620,6 +620,9 @@ type Endpoint interface { // SetOwner sets the task owner to the endpoint owner. SetOwner(owner PacketOwner) + + // LastError clears and returns the last error reported by the endpoint. + LastError() *Error } // LinkPacketInfo holds Link layer information for a received packet. @@ -839,10 +842,6 @@ const ( PMTUDiscoveryProbe ) -// ErrorOption is used in GetSockOpt to specify that the last error reported by -// the endpoint should be cleared and returned. -type ErrorOption struct{} - // BindToDeviceOption is used by SetSockOpt/GetSockOpt to specify that sockets // should bind only on a specific NIC. type BindToDeviceOption NICID -- cgit v1.2.3