wgengine/router: refactor udm-pro into broader ubnt support

Fixes #14453

Signed-off-by: Jason Barnett <J@sonBarnett.com>

version/distro/distro.go

@@ -9,7 +9,6 @@ import (
 	"os"
 	"runtime"
 	"strconv"
-	"strings"
 
 	"tailscale.com/types/lazy"
 	"tailscale.com/util/lineiter"
@@ -31,7 +30,7 @@ const (
 	WDMyCloud = Distro("wdmycloud")
 	Unraid    = Distro("unraid")
 	Alpine    = Distro("alpine")
-	UDMPro    = Distro("udmpro")
+	UBNT      = Distro("ubnt") // Ubiquiti Networks
 )
 
 var distro lazy.SyncValue[Distro]
@@ -77,9 +76,12 @@ func linuxDistro() Distro {
 	case have("/usr/local/bin/freenas-debug"):
 		// TrueNAS Scale runs on debian
 		return TrueNAS
-	case isUDMPro():
-		// UDM-Pro runs on debian
-		return UDMPro
+	case have("/usr/bin/ubnt-device-info"):
+		// UBNT runs on Debian-based systems. This MUST be checked before Debian.
+		//
+		// Currently supported product families:
+		// - UDM (UniFi Dream Machine, UDM-Pro)
+		return UBNT
 	case have("/etc/debian_version"):
 		return Debian
 	case have("/etc/arch-release"):
@@ -152,44 +154,3 @@ func DSMVersion() int {
 		return 0
 	})
 }
-
-// isUDMPro checks a couple of files known to exist on a UDM-Pro and returns
-// true if the expected content exists in the files.
-func isUDMPro() bool {
-	// This is a performance guardrail against trying to load both
-	// /etc/board.info and /sys/firmware/devicetree/base/soc/board-cfg/id when
-	// not running on Debian so we don't make unnecessary calls in situations
-	// where we definitely are NOT on a UDM Pro. In other words, the have() call
-	// is much cheaper than the two os.ReadFile() in fileContainsAnyString().
-	// That said, on Debian systems we will still be making the two
-	// os.ReadFile() in fileContainsAnyString().
-	if !have("/etc/debian_version") {
-		return false
-	}
-	if exists, err := fileContainsAnyString("/etc/board.info", "UDMPRO", "Dream Machine PRO"); err == nil && exists {
-		return true
-	}
-	if exists, err := fileContainsAnyString("/sys/firmware/devicetree/base/soc/board-cfg/id", "udm pro"); err == nil && exists {
-		return true
-	}
-	return false
-}
-
-// fileContainsAnyString is used to determine if one or more of the provided
-// strings exists in a file. This is not efficient for larger files. If you want
-// to use this function to parse large files, please refactor to use
-// `io.LimitedReader`.
-func fileContainsAnyString(filePath string, searchStrings ...string) (bool, error) {
-	data, err := os.ReadFile(filePath)
-	if err != nil {
-		return false, err
-	}
-
-	content := string(data)
-	for _, searchString := range searchStrings {
-		if strings.Contains(content, searchString) {
-			return true, nil
-		}
-	}
-	return false, nil
-}

wgengine/router/router_linux.go

@@ -1184,7 +1184,7 @@ var (
 )
 
 // baseIPRules are the policy routing rules that Tailscale uses, when not
-// running on a UDM-Pro.
+// running on a UBNT device.
 //
 // The priority is the value represented here added to r.ipPolicyPrefBase,
 // which is usually 5200.
@@ -1236,15 +1236,15 @@ var baseIPRules = []netlink.Rule{
 	// usual rules (pref 32766 and 32767, ie. main and default).
 }
 
-// udmProIPRules are the policy routing rules that Tailscale uses, when running
-// on a UDM-Pro.
+// ubntIPRules are the policy routing rules that Tailscale uses, when running
+// on a UBNT device.
 //
 // The priority is the value represented here added to
 // r.ipPolicyPrefBase, which is usually 5200.
 //
 // This represents an experiment that will be used to gather more information.
 // If this goes well, Tailscale may opt to use this for all of Linux.
-var udmProIPRules = []netlink.Rule{
+var ubntIPRules = []netlink.Rule{
 	// non-fwmark packets fall through to the usual rules (pref 32766 and 32767,
 	// ie. main and default).
 	{
@@ -1256,10 +1256,10 @@ var udmProIPRules = []netlink.Rule{
 }
 
 // ipRules returns the appropriate list of ip rules to be used by Tailscale. See
-// comments on baseIPRules and udmProIPRules for more details.
+// comments on baseIPRules and ubntIPRules for more details.
 func ipRules() []netlink.Rule {
-	if getDistroFunc() == distro.UDMPro {
-		return udmProIPRules
+	if getDistroFunc() == distro.UBNT {
+		return ubntIPRules
 	}
 	return baseIPRules
 }

wgengine/router/router_linux_test.go

@@ -1233,14 +1233,14 @@ func adjustFwmask(t *testing.T, s string) string {
 	return fwmaskAdjustRe.ReplaceAllString(s, "$1")
 }
 
-func TestIPRulesForUDMPro(t *testing.T) {
+func TestIPRulesForUBNT(t *testing.T) {
 	// Override the global getDistroFunc
 	getDistroFunc = func() distro.Distro {
-		return distro.UDMPro
+		return distro.UBNT
 	}
 	defer func() { getDistroFunc = distro.Get }() // Restore original after the test
 
-	expected := udmProIPRules
+	expected := ubntIPRules
 	actual := ipRules()
 
 	if len(expected) != len(actual) {