Populate EgressRoute, GSO, Netproto in NIC

fdbased and qdisc layers expect these fields to already be
populated before being reached.

PiperOrigin-RevId: 353099492

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

@@ -165,12 +165,15 @@ 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:
+//  - 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) {
 	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/stack/nic.go

@@ -344,6 +344,9 @@ func (n *NIC) writePacket(r RouteInfo, gso *GSO, protocol tcpip.NetworkProtocolN
 	// WritePacket takes ownership of pkt, calculate numBytes first.
 	numBytes := pkt.Size()
 
+	pkt.EgressRoute = r
+	pkt.GSOOptions = gso
+	pkt.NetworkProtocolNumber = protocol
 	if err := n.LinkEndpoint.WritePacket(r, gso, protocol, pkt); err != nil {
 		return err
 	}
@@ -357,7 +360,14 @@ func (n *NIC) writePacket(r RouteInfo, gso *GSO, protocol tcpip.NetworkProtocolN
 func (n *NIC) WritePackets(r *Route, gso *GSO, pkts PacketBufferList, protocol tcpip.NetworkProtocolNumber) (int, *tcpip.Error) {
 	// TODO(gvisor.dev/issue/4458): Queue packets whie link address resolution
 	// is being peformed like WritePacket.
-	writtenPackets, err := n.LinkEndpoint.WritePackets(r.Fields(), gso, pkts, protocol)
+	routeInfo := r.Fields()
+	for pkt := pkts.Front(); pkt != nil; pkt = pkt.Next() {
+		pkt.EgressRoute = routeInfo
+		pkt.GSOOptions = gso
+		pkt.NetworkProtocolNumber = protocol
+	}
+
+	writtenPackets, err := n.LinkEndpoint.WritePackets(routeInfo, gso, pkts, protocol)
 	n.stats.Tx.Packets.IncrementBy(uint64(writtenPackets))
 	writtenBytes := 0
 	for i, pb := 0, pkts.Front(); i < writtenPackets && pb != nil; i, pb = i+1, pb.Next() {