Implement splice methods for pipes and sockets.

This also allows the tee(2) implementation to be enabled, since dup can now be
properly supported via WriteTo.

Note that this change necessitated some minor restructoring with the
fs.FileOperations splice methods. If the *fs.File is passed through directly,
then only public API methods are accessible, which will deadlock immediately
since the locking is already done by fs.Splice. Instead, we pass through an
abstract io.Reader or io.Writer, which elide locks and use the underlying
fs.FileOperations directly.

PiperOrigin-RevId: 268805207

1 files changed, 3 insertions, 4 deletions

diff --git a/pkg/tcpip/transport/raw/endpoint.go b/pkg/tcpip/transport/raw/endpoint.go
index 13e17e2a6..cf1c5c433 100644
--- a/pkg/tcpip/transport/raw/endpoint.go
+++ b/pkg/tcpip/transport/raw/endpoint.go
@@ -207,7 +207,7 @@ func (ep *endpoint) Read(addr *tcpip.FullAddress) (buffer.View, tcpip.ControlMes
 }
 
 // Write implements tcpip.Endpoint.Write.
-func (ep *endpoint) Write(payload tcpip.Payload, opts tcpip.WriteOptions) (int64, <-chan struct{}, *tcpip.Error) {
+func (ep *endpoint) Write(p tcpip.Payloader, opts tcpip.WriteOptions) (int64, <-chan struct{}, *tcpip.Error) {
 	// MSG_MORE is unimplemented. This also means that MSG_EOR is a no-op.
 	if opts.More {
 		return 0, nil, tcpip.ErrInvalidOptionValue
@@ -220,9 +220,8 @@ func (ep *endpoint) Write(payload tcpip.Payload, opts tcpip.WriteOptions) (int64
 		return 0, nil, tcpip.ErrInvalidEndpointState
 	}
 
-	payloadBytes, err := payload.Get(payload.Size())
+	payloadBytes, err := p.FullPayload()
 	if err != nil {
-		ep.mu.RUnlock()
 		return 0, nil, err
 	}
 
@@ -230,7 +229,7 @@ func (ep *endpoint) Write(payload tcpip.Payload, opts tcpip.WriteOptions) (int64
 	// destination address, route using that address.
 	if !ep.associated {
 		ip := header.IPv4(payloadBytes)
-		if !ip.IsValid(payload.Size()) {
+		if !ip.IsValid(len(payloadBytes)) {
 			ep.mu.RUnlock()
 			return 0, nil, tcpip.ErrInvalidOptionValue
 		}