net/{interfaces,netns}: change which build tag means mac/ios Network/System Extension

We used to use "redo" for that, but it was pretty vague.

Also, fix the build tags broken in interfaces_default_route_test.go from
a9745a0b684bb92ccb1965709adea6e9a98c0cd6, moving those Linux-specific
tests to interfaces_linux_test.go.

Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>

ipn/ipnlocal/peerapi_macios_ext.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build darwin,redo ios,redo
+// +build darwin,ts_macext ios,ts_macext
 
 package ipnlocal
 

net/interfaces/interfaces_default_route_test.go

@@ -2,15 +2,11 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build linux,!redo
+// +build linux darwin,!ts_macext
 
 package interfaces
 
 import (
-	"fmt"
-	"io/ioutil"
-	"os"
-	"path/filepath"
 	"testing"
 )
 
@@ -23,64 +19,3 @@ func TestDefaultRouteInterface(t *testing.T) {
 	}
 	t.Logf("got %q", v)
 }
-
-// test the specific /proc/net/route path as found on Google Cloud Run instances
-func TestGoogleCloudRunDefaultRouteInterface(t *testing.T) {
-	dir := t.TempDir()
-	savedProcNetRoutePath := procNetRoutePath
-	defer func() { procNetRoutePath = savedProcNetRoutePath }()
-	procNetRoutePath = filepath.Join(dir, "CloudRun")
-	buf := []byte("Iface\tDestination\tGateway\tFlags\tRefCnt\tUse\tMetric\tMask\tMTU\tWindow\tIRTT\n" +
-		"eth0\t8008FEA9\t00000000\t0001\t0\t0\t0\t01FFFFFF\t0\t0\t0\n" +
-		"eth1\t00000000\t00000000\t0001\t0\t0\t0\t00000000\t0\t0\t0\n")
-	err := ioutil.WriteFile(procNetRoutePath, buf, 0644)
-	if err != nil {
-		t.Fatal(err)
-	}
-	got, err := DefaultRouteInterface()
-	if err != nil {
-		t.Fatal(err)
-	}
-
-	if got != "eth1" {
-		t.Fatalf("got %s, want eth1", got)
-	}
-}
-
-// we read chunks of /proc/net/route at a time, test that files longer than the chunk
-// size can be handled.
-func TestExtremelyLongProcNetRoute(t *testing.T) {
-	dir := t.TempDir()
-	savedProcNetRoutePath := procNetRoutePath
-	defer func() { procNetRoutePath = savedProcNetRoutePath }()
-	procNetRoutePath = filepath.Join(dir, "VeryLong")
-	f, err := os.Create(procNetRoutePath)
-	if err != nil {
-		t.Fatal(err)
-	}
-	_, err = f.Write([]byte("Iface\tDestination\tGateway\tFlags\tRefCnt\tUse\tMetric\tMask\tMTU\tWindow\tIRTT\n"))
-	if err != nil {
-		t.Fatal(err)
-	}
-
-	for n := 0; n <= 1000; n++ {
-		line := fmt.Sprintf("eth%d\t8008FEA9\t00000000\t0001\t0\t0\t0\t01FFFFFF\t0\t0\t0\n", n)
-		_, err := f.Write([]byte(line))
-		if err != nil {
-			t.Fatal(err)
-		}
-	}
-	_, err = f.Write([]byte("tokenring1\t00000000\t00000000\t0001\t0\t0\t0\t00000000\t0\t0\t0\n"))
-	if err != nil {
-		t.Fatal(err)
-	}
-
-	got, err := DefaultRouteInterface()
-	if err != nil {
-		t.Fatal(err)
-	}
-
-	if got != "tokenring1" {
-		t.Fatalf("got %q, want tokenring1", got)
-	}
-}

net/interfaces/interfaces_linux_test.go

@@ -4,7 +4,74 @@
 
 package interfaces
 
-import "testing"
+import (
+	"fmt"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+// test the specific /proc/net/route path as found on Google Cloud Run instances
+func TestGoogleCloudRunDefaultRouteInterface(t *testing.T) {
+	dir := t.TempDir()
+	savedProcNetRoutePath := procNetRoutePath
+	defer func() { procNetRoutePath = savedProcNetRoutePath }()
+	procNetRoutePath = filepath.Join(dir, "CloudRun")
+	buf := []byte("Iface\tDestination\tGateway\tFlags\tRefCnt\tUse\tMetric\tMask\tMTU\tWindow\tIRTT\n" +
+		"eth0\t8008FEA9\t00000000\t0001\t0\t0\t0\t01FFFFFF\t0\t0\t0\n" +
+		"eth1\t00000000\t00000000\t0001\t0\t0\t0\t00000000\t0\t0\t0\n")
+	err := ioutil.WriteFile(procNetRoutePath, buf, 0644)
+	if err != nil {
+		t.Fatal(err)
+	}
+	got, err := DefaultRouteInterface()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if got != "eth1" {
+		t.Fatalf("got %s, want eth1", got)
+	}
+}
+
+// we read chunks of /proc/net/route at a time, test that files longer than the chunk
+// size can be handled.
+func TestExtremelyLongProcNetRoute(t *testing.T) {
+	dir := t.TempDir()
+	savedProcNetRoutePath := procNetRoutePath
+	defer func() { procNetRoutePath = savedProcNetRoutePath }()
+	procNetRoutePath = filepath.Join(dir, "VeryLong")
+	f, err := os.Create(procNetRoutePath)
+	if err != nil {
+		t.Fatal(err)
+	}
+	_, err = f.Write([]byte("Iface\tDestination\tGateway\tFlags\tRefCnt\tUse\tMetric\tMask\tMTU\tWindow\tIRTT\n"))
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	for n := 0; n <= 1000; n++ {
+		line := fmt.Sprintf("eth%d\t8008FEA9\t00000000\t0001\t0\t0\t0\t01FFFFFF\t0\t0\t0\n", n)
+		_, err := f.Write([]byte(line))
+		if err != nil {
+			t.Fatal(err)
+		}
+	}
+	_, err = f.Write([]byte("tokenring1\t00000000\t00000000\t0001\t0\t0\t0\t00000000\t0\t0\t0\n"))
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	got, err := DefaultRouteInterface()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if got != "tokenring1" {
+		t.Fatalf("got %q, want tokenring1", got)
+	}
+}
 
 func BenchmarkDefaultRouteInterface(b *testing.B) {
 	b.ReportAllocs()

net/netns/netns_darwin_tailscaled.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build darwin,!redo
+// +build darwin,!ts_macext
 
 package netns
 

net/netns/netns_default.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build !linux,!windows,!darwin darwin,redo
+// +build !linux,!windows,!darwin darwin,ts_macext
 
 package netns