wgengine/router: avoid unncessary routing configuration changes

The iOS and macOS networking extension API only exposes a single setter for the entire routing and DNS configuration, and does not appear to do any kind of diffing or deltas when applying changes. This results in spurious "network changed" errors in Chrome, even when the `OneCGNATRoute` flag from df9ce972c7 is used (because we're setting the same configuration repeatedly). Since we already keep track of the current routing and DNS configuration in CallbackRouter, use that to detect if they're actually changing, and only invoke the platform setter if it's actually necessary. Updates #3102 Signed-off-by: Mihai Parparita <mihai@tailscale.com>
2022-06-28 15:32:09 -07:00
parent 3b1f99ded1
commit 06aa141632
3 changed files with 150 additions and 5 deletions
@@ -2,12 +2,15 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.

-//go:build linux || windows
-// +build linux windows
-
 package router

-import "inet.af/netaddr"
+import (
+	"reflect"
+	"testing"
+
+	"inet.af/netaddr"
+	"tailscale.com/types/preftype"
+)

 func mustCIDRs(ss ...string) []netaddr.IPPrefix {
 	var ret []netaddr.IPPrefix
@@ -16,3 +19,127 @@ func mustCIDRs(ss ...string) []netaddr.IPPrefix {
 	}
 	return ret
 }
+
+func TestConfigEqual(t *testing.T) {
+	testedFields := []string{
+		"LocalAddrs", "Routes", "LocalRoutes", "SubnetRoutes",
+		"SNATSubnetRoutes", "NetfilterMode",
+	}
+	configType := reflect.TypeOf(Config{})
+	configFields := []string{}
+	for i := 0; i < configType.NumField(); i++ {
+		configFields = append(configFields, configType.Field(i).Name)
+	}
+	if !reflect.DeepEqual(configFields, testedFields) {
+		t.Errorf("Config.Equal check might be out of sync\nfields: %q\nhandled: %q\n",
+			configFields, testedFields)
+	}
+
+	nets := func(strs ...string) (ns []netaddr.IPPrefix) {
+		for _, s := range strs {
+			n, err := netaddr.ParseIPPrefix(s)
+			if err != nil {
+				panic(err)
+			}
+			ns = append(ns, n)
+		}
+		return ns
+	}
+	tests := []struct {
+		a, b *Config
+		want bool
+	}{
+		{
+			nil,
+			nil,
+			true,
+		},
+		{
+			&Config{},
+			nil,
+			false,
+		},
+		{
+			nil,
+			&Config{},
+			false,
+		},
+		{
+			&Config{},
+			&Config{},
+			true,
+		},
+
+		{
+			&Config{LocalAddrs: nets("100.1.27.82/32")},
+			&Config{LocalAddrs: nets("100.2.19.82/32")},
+			false,
+		},
+		{
+			&Config{LocalAddrs: nets("100.1.27.82/32")},
+			&Config{LocalAddrs: nets("100.1.27.82/32")},
+			true,
+		},
+
+		{
+			&Config{Routes: nets("100.1.27.0/24")},
+			&Config{Routes: nets("100.2.19.0/24")},
+			false,
+		},
+		{
+			&Config{Routes: nets("100.2.19.0/24")},
+			&Config{Routes: nets("100.2.19.0/24")},
+			true,
+		},
+
+		{
+			&Config{LocalRoutes: nets("100.1.27.0/24")},
+			&Config{LocalRoutes: nets("100.2.19.0/24")},
+			false,
+		},
+		{
+			&Config{LocalRoutes: nets("100.1.27.0/24")},
+			&Config{LocalRoutes: nets("100.1.27.0/24")},
+			true,
+		},
+
+		{
+			&Config{SubnetRoutes: nets("100.1.27.0/24")},
+			&Config{SubnetRoutes: nets("100.2.19.0/24")},
+			false,
+		},
+		{
+			&Config{SubnetRoutes: nets("100.1.27.0/24")},
+			&Config{SubnetRoutes: nets("100.1.27.0/24")},
+			true,
+		},
+
+		{
+			&Config{SNATSubnetRoutes: false},
+			&Config{SNATSubnetRoutes: true},
+			false,
+		},
+		{
+			&Config{SNATSubnetRoutes: false},
+			&Config{SNATSubnetRoutes: false},
+			true,
+		},
+
+		{
+			&Config{NetfilterMode: preftype.NetfilterOff},
+			&Config{NetfilterMode: preftype.NetfilterNoDivert},
+			false,
+		},
+		{
+			&Config{NetfilterMode: preftype.NetfilterNoDivert},
+			&Config{NetfilterMode: preftype.NetfilterNoDivert},
+			true,
+		},
+	}
+	for i, tt := range tests {
+		got := tt.a.Equal(tt.b)
+		if got != tt.want {
+			t.Errorf("%d. Equal = %v; want %v", i, got, tt.want)
+		}
+	}
+}