libnet/portmapper: remove dead DeleteForwardingTableEntry

Prior to commit 4f09af626, DeleteForwardingTableEntry had a Linux
implementation. That's not the case anymore, and it's a no-op on
Windows. Remove it.

Signed-off-by: Albin Kerouanton <albinker@gmail.com>

daemon/libnetwork/portmapper/mapper.go

@@ -123,15 +123,11 @@ func (pm *PortMapper) MapRange(container net.Addr, hostIP net.IP, hostPortStart,
 		return nil, ErrPortMappedForIP
 	}
 
-	containerIP, containerPort := getIPAndPort(m.container)
-
 	var err error
 	m.stopUserlandProxy, err = newDummyProxy(m.proto, hostIP, allocatedHostPort)
 	if err != nil {
 		// FIXME(thaJeztah): both stopping the proxy and deleting iptables rules can produce an error, and both are not currently handled.
 		m.stopUserlandProxy()
-		// need to undo the iptables rules before we return
-		pm.DeleteForwardingTableEntry(m.proto, hostIP, allocatedHostPort, containerIP.String(), containerPort)
 		return nil, err
 	}
 
@@ -156,12 +152,6 @@ func (pm *PortMapper) Unmap(host net.Addr) error {
 
 	delete(pm.currentMappings, key)
 
-	containerIP, containerPort := getIPAndPort(data.container)
-	hostIP, hostPort := getIPAndPort(data.host)
-	if err := pm.DeleteForwardingTableEntry(data.proto, hostIP, hostPort, containerIP.String(), containerPort); err != nil {
-		log.G(context.TODO()).Errorf("Error on iptables delete: %s", err)
-	}
-
 	switch a := host.(type) {
 	case *net.TCPAddr:
 		pm.allocator.ReleasePort(a.IP, "tcp", a.Port)

daemon/libnetwork/portmapper/mapper_windows.go

@@ -1,7 +1,6 @@
 package portmapper
 
 import (
-	"net"
 	"sync"
 
 	"github.com/moby/moby/v2/daemon/libnetwork/portallocator"
@@ -19,8 +18,3 @@ type PortMapper struct {
 
 	allocator *portallocator.PortAllocator
 }
-
-// DeleteForwardingTableEntry removes a port mapping from the forwarding table
-func (pm *PortMapper) DeleteForwardingTableEntry(proto string, sourceIP net.IP, sourcePort int, containerIP string, containerPort int) error {
-	return nil
-}