Populate EgressRoute, GSO, Netproto for batch writes

We loop over the list of packets anyways so setting these aren't
expensive.

Now that they are populated only by the link endpoint that uses them,
TCP does not need to.

PiperOrigin-RevId: 352090853

pkg/tcpip/link/packetsocket/endpoint.go

@@ -43,7 +43,7 @@ func (e *endpoint) WritePacket(r *stack.Route, gso *stack.GSO, protocol tcpip.Ne
 // WritePackets implements stack.LinkEndpoint.WritePackets.
 func (e *endpoint) WritePackets(r *stack.Route, gso *stack.GSO, pkts stack.PacketBufferList, proto tcpip.NetworkProtocolNumber) (int, *tcpip.Error) {
 	for pkt := pkts.Front(); pkt != nil; pkt = pkt.Next() {
-		e.Endpoint.DeliverOutboundPacket(pkt.EgressRoute.RemoteLinkAddress(), pkt.EgressRoute.LocalLinkAddress, pkt.NetworkProtocolNumber, pkt)
+		e.Endpoint.DeliverOutboundPacket(r.RemoteLinkAddress(), r.LocalLinkAddress, pkt.NetworkProtocolNumber, pkt)
 	}
 
 	return e.Endpoint.WritePackets(r, gso, pkts, proto)

pkg/tcpip/link/qdisc/fifo/endpoint.go

@@ -166,15 +166,12 @@ func (e *endpoint) WritePacket(r *stack.Route, gso *stack.GSO, protocol tcpip.Ne
 }
 
 // WritePackets implements stack.LinkEndpoint.WritePackets.
-//
-// Being a batch API, each packet in pkts should have the following fields
-// populated:
-//   - pkt.EgressRoute
-//   - pkt.GSOOptions
-//   - pkt.NetworkProtocolNumber
-func (e *endpoint) WritePackets(_ *stack.Route, _ *stack.GSO, pkts stack.PacketBufferList, _ tcpip.NetworkProtocolNumber) (int, *tcpip.Error) {
+func (e *endpoint) WritePackets(r *stack.Route, gso *stack.GSO, pkts stack.PacketBufferList, protocol tcpip.NetworkProtocolNumber) (int, *tcpip.Error) {
 	enqueued := 0
 	for pkt := pkts.Front(); pkt != nil; {
+		pkt.EgressRoute = r
+		pkt.GSOOptions = gso
+		pkt.NetworkProtocolNumber = protocol
 		d := e.dispatchers[int(pkt.Hash)%len(e.dispatchers)]
 		nxt := pkt.Next()
 		if !d.q.enqueue(pkt) {

pkg/tcpip/transport/tcp/connect.go

@@ -784,9 +784,6 @@ func sendTCPBatch(r *stack.Route, tf tcpFields, data buffer.VectorisedView, gso
 		})
 		pkt.Hash = tf.txHash
 		pkt.Owner = owner
-		pkt.EgressRoute = r
-		pkt.GSOOptions = gso
-		pkt.NetworkProtocolNumber = r.NetProto
 		data.ReadToVV(&pkt.Data, packetSize)
 		buildTCPHdr(r, tf, pkt, gso)
 		tf.seq = tf.seq.Add(seqnum.Size(packetSize))