Add "ignore" option to port forwarding settings

Signed-off-by: Jan Dubois <[email protected]>

Author: jandubois

pkg/hostagent/hostagent.go

@@ -86,12 +86,17 @@ func New(instName string, stdout, stderr io.Writer, sigintCh chan os.Signal) (*H
 		AdditionalArgs: sshArgs,
 	}
 
+	ports := make([]limayaml.Port, 0, 2+len(y.Ports))
+	ports = append(ports, limayaml.Port{GuestPort: sshGuestPort, Ignore: true})
+	ports = append(ports, limayaml.Port{GuestPort: y.SSH.LocalPort, Ignore: true})
+	ports = append(ports, y.Ports...)
+
 	a := &HostAgent{
 		l:             l,
 		y:             y,
 		instDir:       inst.Dir,
 		sshConfig:     sshConfig,
-		portForwarder: newPortForwarder(l, sshConfig, y.SSH.LocalPort, y.Ports),
+		portForwarder: newPortForwarder(l, sshConfig, y.SSH.LocalPort, ports),
 		qExe:          qExe,
 		qArgs:         qArgs,
 		sigintCh:      sigintCh,

pkg/hostagent/port.go

@@ -31,35 +31,30 @@ func newPortForwarder(l *logrus.Logger, sshConfig *ssh.SSHConfig, sshHostPort in
 	}
 }
 
-func (pf *portForwarder) forwardingAddresses(guestPort int) (string, string) {
+func (pf *portForwarder) forwardingAddresses(guest api.IPPort) (string, string) {
 	for _, port := range pf.ports {
-		if port.GuestPortRange[0] <= guestPort && guestPort <= port.GuestPortRange[1] {
-			guestAddr := fmt.Sprintf("%s:%d", port.GuestIP, guestPort)
+		if port.GuestPortRange[0] <= guest.Port && guest.Port <= port.GuestPortRange[1] {
+			guestAddr := fmt.Sprintf("%s:%d", port.GuestIP, guest.Port)
+			if port.Ignore {
+				return guestAddr, ""
+			}
 			offset := port.HostPortRange[0] - port.GuestPortRange[0]
-			hostAddr := fmt.Sprintf("%s:%d", port.HostIP, guestPort + offset)
+			hostAddr := fmt.Sprintf("%s:%d", port.HostIP, guest.Port + offset)
 			return guestAddr, hostAddr
 		}
 	}
-	addr := "127.0.0.1:" + strconv.Itoa(guestPort)
+	addr := "127.0.0.1:" + strconv.Itoa(guest.Port)
 	return addr, addr
 }
 
 func (pf *portForwarder) OnEvent(ctx context.Context, ev api.Event) {
-	ignore := func(x api.IPPort) bool {
-		switch x.Port {
-		case sshGuestPort, pf.sshHostPort:
-			return true
-		default:
-			return false
-		}
-	}
 	for _, f := range ev.LocalPortsRemoved {
-		if ignore(f) {
-			continue
-		}
 		// pf.tcp might be inconsistent with the actual state of the SSH master,
 		// so we always attempt to cancel forwarding, even when f.Port is not tracked in pf.tcp.
-		guestAddr, hostAddr := pf.forwardingAddresses(f.Port)
+		guestAddr, hostAddr := pf.forwardingAddresses(f)
+		if hostAddr == "" {
+			continue
+		}
 		pf.l.Infof("Stopping forwarding TCP from %s to %s", guestAddr, hostAddr)
 		verbCancel := true
 		if err := forwardSSH(ctx, pf.sshConfig, pf.sshHostPort, hostAddr, guestAddr, verbCancel); err != nil {
@@ -72,10 +67,11 @@ func (pf *portForwarder) OnEvent(ctx context.Context, ev api.Event) {
 		delete(pf.tcp, f.Port)
 	}
 	for _, f := range ev.LocalPortsAdded {
-		if ignore(f) {
+		guestAddr, hostAddr := pf.forwardingAddresses(f)
+		if hostAddr == "" {
+			pf.l.Infof("Not forwarding TCP from %s", guestAddr)
 			continue
 		}
-		guestAddr, hostAddr := pf.forwardingAddresses(f.Port)
 		pf.l.Infof("Forwarding TCP from %s to %s", guestAddr, hostAddr)
 		if err := forwardSSH(ctx, pf.sshConfig, pf.sshHostPort, hostAddr, guestAddr, false); err != nil {
 			pf.l.WithError(err).Warnf("failed to setting up forward TCP port %d (negligible if already forwarded)", f.Port)

pkg/limayaml/default.yaml

@@ -90,6 +90,8 @@ containerd:
 #   - guestPort: 80
 #     hostPort: 8080 # overrides the default value 80
 
+#   - guestPort: 8888
+#     ignore: true (don't forward this port)
 
 # Provisioning scripts need to be idempotent because they might be called
 # multiple times, e.g. when the host VM is being restarted.

pkg/limayaml/limayaml.go

@@ -99,4 +99,5 @@ type Port struct {
 	HostPort       int    `yaml:"hostPort,omitempty"`
 	HostPortRange  [2]int `yaml:"hostPortRange,omitempty"`
 	Proto          Proto  `yaml:"proto,omitempty"`
+	Ignore         bool   `yaml:"ignore,omitempty"`
 }