Only carry GSO options in the packet buffer

With this change, GSO options no longer needs to be passed around as
a function argument in the write path.

This change is done in preparation for a later change that defers
segmentation, and may change GSO options for a packet as it flows
down the stack.

Updates #170.

PiperOrigin-RevId: 369774872

1 files changed, 10 insertions, 10 deletions

diff --git a/pkg/tcpip/link/qdisc/fifo/endpoint.go b/pkg/tcpip/link/qdisc/fifo/endpoint.go
index 128ef6e87..bba6a6973 100644
--- a/pkg/tcpip/link/qdisc/fifo/endpoint.go
+++ b/pkg/tcpip/link/qdisc/fifo/endpoint.go
@@ -91,7 +91,7 @@ func (q *queueDispatcher) dispatchLoop() {
 			}
 			// We pass a protocol of zero here because each packet carries its
 			// NetworkProtocol.
-			q.lower.WritePackets(stack.RouteInfo{}, nil /* gso */, batch, 0 /* protocol */)
+			q.lower.WritePackets(stack.RouteInfo{}, batch, 0 /* protocol */)
 			for pkt := batch.Front(); pkt != nil; pkt = pkt.Next() {
 				batch.Remove(pkt)
 			}
@@ -150,12 +150,12 @@ func (e *endpoint) GSOMaxSize() uint32 {
 }
 
 // WritePacket implements stack.LinkEndpoint.WritePacket.
-func (e *endpoint) WritePacket(r stack.RouteInfo, gso *stack.GSO, protocol tcpip.NetworkProtocolNumber, pkt *stack.PacketBuffer) tcpip.Error {
-	// WritePacket caller's do not set the following fields in PacketBuffer
-	// so we populate them here.
-	pkt.EgressRoute = r
-	pkt.GSOOptions = gso
-	pkt.NetworkProtocolNumber = protocol
+//
+// The packet must have the following fields populated:
+//  - pkt.EgressRoute
+//  - pkt.GSOOptions
+//  - pkt.NetworkProtocolNumber
+func (e *endpoint) WritePacket(r stack.RouteInfo, protocol tcpip.NetworkProtocolNumber, pkt *stack.PacketBuffer) tcpip.Error {
 	d := e.dispatchers[int(pkt.Hash)%len(e.dispatchers)]
 	if !d.q.enqueue(pkt) {
 		return &tcpip.ErrNoBufferSpace{}
@@ -166,12 +166,12 @@ func (e *endpoint) WritePacket(r stack.RouteInfo, gso *stack.GSO, protocol tcpip
 
 // WritePackets implements stack.LinkEndpoint.WritePackets.
 //
-// Being a batch API, each packet in pkts should have the following
-// fields populated:
+// Each packet in the packet buffer list must have the following fields
+// populated:
 //  - pkt.EgressRoute
 //  - pkt.GSOOptions
 //  - pkt.NetworkProtocolNumber
-func (e *endpoint) WritePackets(r stack.RouteInfo, gso *stack.GSO, pkts stack.PacketBufferList, protocol tcpip.NetworkProtocolNumber) (int, tcpip.Error) {
+func (e *endpoint) WritePackets(r stack.RouteInfo, pkts stack.PacketBufferList, protocol tcpip.NetworkProtocolNumber) (int, tcpip.Error) {
 	enqueued := 0
 	for pkt := pkts.Front(); pkt != nil; {
 		d := e.dispatchers[int(pkt.Hash)%len(e.dispatchers)]