Make UDP traceroute work.

Adds support to generate Port Unreachable messages for UDP
datagrams received on a port for which there is no valid
endpoint.

Fixes #703

PiperOrigin-RevId: 267034418

1 files changed, 11 insertions, 1 deletions

diff --git a/pkg/tcpip/stack/nic.go b/pkg/tcpip/stack/nic.go
index f947b55db..ae56e0ffd 100644
--- a/pkg/tcpip/stack/nic.go
+++ b/pkg/tcpip/stack/nic.go
@@ -679,7 +679,7 @@ func (n *NIC) DeliverTransportPacket(r *Route, protocol tcpip.TransportProtocolN
 
 	// We could not find an appropriate destination for this packet, so
 	// deliver it to the global handler.
-	if !transProto.HandleUnknownDestinationPacket(r, id, vv) {
+	if !transProto.HandleUnknownDestinationPacket(r, id, netHeader, vv) {
 		n.stack.stats.MalformedRcvdPackets.Increment()
 	}
 }
@@ -720,6 +720,11 @@ func (n *NIC) ID() tcpip.NICID {
 	return n.id
 }
 
+// Stack returns the instance of the Stack that owns this NIC.
+func (n *NIC) Stack() *Stack {
+	return n.stack
+}
+
 type networkEndpointKind int32
 
 const (
@@ -823,3 +828,8 @@ func (r *referencedNetworkEndpoint) tryIncRef() bool {
 		}
 	}
 }
+
+// stack returns the Stack instance that owns the underlying endpoint.
+func (r *referencedNetworkEndpoint) stack() *Stack {
+	return r.nic.stack
+}