cmd/cli: extend list of valid interfaces for MacOS

By parsing "networksetup -listallhardwareports" output to get list of
available hardware ports.

cmd/cli/net_darwin.go

@@ -43,22 +43,32 @@ func networkServiceName(ifaceName string, r io.Reader) string {
 	return ""
 }
 
-// validInterface reports whether the *net.Interface is a valid one, which includes en0 -> en10.
-// - en0: physical wireless
-// - en1: Thunderbolt 1
-// - en2: Thunderbolt 2
-// - en3: Thunderbolt 3
-// - en4: Thunderbolt 4
-// - ...
-// - en10: iPad
-//
-// For full list, see: https://unix.stackexchange.com/questions/603506/what-are-these-ifconfig-interfaces-on-macos
-func validInterface(iface *net.Interface) bool {
-	switch iface.Name {
-	case "en0", "en1", "en2", "en3", "en4", "en5",
-		"en6", "en7", "en8", "en9", "en10":
-		return true
-	default:
-		return false
-	}
+// validInterface reports whether the *net.Interface is a valid one.
+func validInterface(iface *net.Interface, validIfacesMap map[string]struct{}) bool {
+	_, ok := validIfacesMap[iface.Name]
+	return ok
+}
+
+func validInterfacesMap() map[string]struct{} {
+	b, err := exec.Command("networksetup", "-listallhardwareports").Output()
+	if err != nil {
+		return nil
+	}
+	return parseListAllHardwarePorts(bytes.NewReader(b))
+}
+
+// parseListAllHardwarePorts parses output of "networksetup -listallhardwareports"
+// and returns map presents all hardware ports.
+func parseListAllHardwarePorts(r io.Reader) map[string]struct{} {
+	m := make(map[string]struct{})
+	scanner := bufio.NewScanner(r)
+	for scanner.Scan() {
+		line := scanner.Text()
+		after, ok := strings.CutPrefix(line, "Device: ")
+		if !ok {
+			continue
+		}
+		m[after] = struct{}{}
+	}
+	return m
 }

cmd/cli/net_darwin_test.go

@@ -1,6 +1,7 @@
 package cli
 
 import (
+	"maps"
 	"strings"
 	"testing"
 
@@ -57,3 +58,47 @@ func Test_networkServiceName(t *testing.T) {
 		})
 	}
 }
+
+const listallhardwareportsOutput = `
+Hardware Port: Ethernet Adapter (en6)
+Device: en6
+Ethernet Address: 3a:3e:fc:1e:ab:41
+
+Hardware Port: Ethernet Adapter (en7)
+Device: en7
+Ethernet Address: 3a:3e:fc:1e:ab:42
+
+Hardware Port: Thunderbolt Bridge
+Device: bridge0
+Ethernet Address: 36:21:bb:3a:7a:40
+
+Hardware Port: Wi-Fi
+Device: en0
+Ethernet Address: a0:78:17:68:56:3f
+
+Hardware Port: Thunderbolt 1
+Device: en1
+Ethernet Address: 36:21:bb:3a:7a:40
+
+Hardware Port: Thunderbolt 2
+Device: en2
+Ethernet Address: 36:21:bb:3a:7a:44
+
+VLAN Configurations
+===================
+`
+
+func Test_parseListAllHardwarePorts(t *testing.T) {
+	expected := map[string]struct{}{
+		"en0":     {},
+		"en1":     {},
+		"en2":     {},
+		"en6":     {},
+		"en7":     {},
+		"bridge0": {},
+	}
+	m := parseListAllHardwarePorts(strings.NewReader(listallhardwareportsOutput))
+	if !maps.Equal(m, expected) {
+		t.Errorf("unexpected output, want: %v, got: %v", expected, m)
+	}
+}

cmd/cli/net_others.go

@@ -6,4 +6,6 @@ import "net"
 
 func patchNetIfaceName(iface *net.Interface) error { return nil }
 
-func validInterface(iface *net.Interface) bool { return true }
+func validInterface(iface *net.Interface, validIfacesMap map[string]struct{}) bool { return true }
+
+func validInterfacesMap() map[string]struct{} { return nil }

cmd/cli/net_windows.go

@@ -10,7 +10,7 @@ func patchNetIfaceName(iface *net.Interface) error {
 
 // validInterface reports whether the *net.Interface is a valid one.
 // On Windows, only physical interfaces are considered valid.
-func validInterface(iface *net.Interface) bool {
+func validInterface(iface *net.Interface, validIfacesMap map[string]struct{}) bool {
 	if iface == nil {
 		return false
 	}
@@ -19,3 +19,5 @@ func validInterface(iface *net.Interface) bool {
 	}
 	return false
 }
+
+func validInterfacesMap() map[string]struct{} { return nil }

cmd/cli/prog.go

@@ -868,13 +868,14 @@ func canBeLocalUpstream(addr string) bool {
 // the interface that matches excludeIfaceName. The context is used to clarify the
 // log message when error happens.
 func withEachPhysicalInterfaces(excludeIfaceName, context string, f func(i *net.Interface) error) {
+	validIfacesMap := validInterfacesMap()
 	interfaces.ForeachInterface(func(i interfaces.Interface, prefixes []netip.Prefix) {
 		// Skip loopback/virtual interface.
 		if i.IsLoopback() || len(i.HardwareAddr) == 0 {
 			return
 		}
 		// Skip invalid interface.
-		if !validInterface(i.Interface) {
+		if !validInterface(i.Interface, validIfacesMap) {
 			return
 		}
 		netIface := i.Interface