sharedmem: mark as GSO-compatible

Really, any LinkWriter is compatible with gVisor GSO: there's nothing special to be done. Anything with a WritePackets method is good to go. PiperOrigin-RevId: 537048401

Author: kevinGC

pkg/tcpip/link/fdbased/endpoint.go

@@ -754,7 +754,7 @@ func (e *endpoint) GSOMaxSize() uint32 {
 returne.gsoMaxSize
 }
 
-// SupportsHWGSO implements stack.GSOEndpoint.
+// SupportedGSO implements stack.GSOEndpoint.
 func (e*endpoint) SupportedGSO() stack.SupportedGSO {
 returne.gsoKind
 }

pkg/tcpip/link/sharedmem/sharedmem.go

@@ -133,8 +133,15 @@ type Options struct {
 // VirtioNetHeaderRequired if true, indicates that all outbound packets should have
 // a virtio header and inbound packets should have a virtio header as well.
 VirtioNetHeaderRequiredbool
+
+// GSOMaxSize is the maximum GSO packet size. It is zero if GSO is
+// disabled. Note that only gVisor GSO is supported, not host GSO.
+GSOMaxSizeuint32
 }
 
+var_ stack.LinkEndpoint= (*endpoint)(nil)
+var_ stack.GSOEndpoint= (*endpoint)(nil)
+
 typeendpointstruct {
 // mtu (maximum transmission unit) is the maximum size of a packet.
 // mtu is immutable.
@@ -160,6 +167,11 @@ type endpoint struct {
 // hdrSize is immutable.
 hdrSizeuint32
 
+// gSOMaxSize is the maximum GSO packet size. It is zero if GSO is
+// disabled. Note that only gVisor GSO is supported, not host GSO.
+// gsoMaxSize is immutable.
+gsoMaxSizeuint32
+
 // virtioNetHeaderRequired if true indicates that a virtio header is expected
 // in all inbound/outbound packets.
 virtioNetHeaderRequiredbool
@@ -202,6 +214,7 @@ func New(opts Options) (stack.LinkEndpoint, error) {
 peerFD: opts.PeerFD,
 onClosed: opts.OnClosed,
 virtioNetHeaderRequired: opts.VirtioNetHeaderRequired,
+gsoMaxSize: opts.GSOMaxSize,
  }
 
 iferr:=e.tx.init(opts.BufferSize, &opts.TX); err!=nil {
@@ -480,3 +493,13 @@ func (e *endpoint) dispatchLoop(d stack.NetworkDispatcher) {
 func (*endpoint) ARPHardwareType() header.ARPHardwareType {
 returnheader.ARPHardwareEther
 }
+
+// GSOMaxSize implements stack.GSOEndpoint.
+func (e*endpoint) GSOMaxSize() uint32 {
+returne.gsoMaxSize
+}
+
+// SupportsGSO implements stack.GSOEndpoint.
+func (e*endpoint) SupportedGSO() stack.SupportedGSO {
+returnstack.GvisorGSOSupported
+}