wgengine: add BSD userspace router to darwin

Darwin and FreeBSD are compatible enough to share the userspace router.

The OSX router delegates to the BSD userspace router unless `SetRoutesFunc` is set.
That preserves the mechanism that allows `ipn-go-bridge` to specify its own routing behavior.

Fixes #177

Signed-off-by: Reinaldo de Souza <github@rei.nal.do>

wgengine/router/router_darwin.go

@@ -13,6 +13,7 @@ import (
 type darwinRouter struct {
 	logf    logger.Logf
 	tunname string
+	Router
 }
 
 func newUserspaceRouter(logf logger.Logf, _ *device.Device, tundev tun.Device) (Router, error) {
@@ -20,26 +21,27 @@ func newUserspaceRouter(logf logger.Logf, _ *device.Device, tundev tun.Device) (
 	if err != nil {
 		return nil, err
 	}
+
+	userspaceRouter, err := newUserspaceBSDRouter(logf, nil, tundev)
+	if err != nil {
+		return nil, err
+	}
+
 	return &darwinRouter{
 		logf:    logf,
 		tunname: tunname,
+		Router:  userspaceRouter,
 	}, nil
 }
 
-func (r *darwinRouter) Up() error {
-	return nil
-}
-
 func (r *darwinRouter) Set(cfg *Config) error {
-	if SetRoutesFunc == nil {
-		return nil
-	}
 	if cfg == nil {
 		cfg = &shutdownConfig
 	}
-	return SetRoutesFunc(cfg)
-}
 
-func (r *darwinRouter) Close() error {
+	if SetRoutesFunc != nil {
-	return nil
+		return SetRoutesFunc(cfg)
+	}
+
+	return r.Router.Set(cfg)
 }

wgengine/router/router_freebsd.go

@@ -5,14 +5,8 @@
 package router
 
 import (
-	"errors"
-	"fmt"
-	"log"
-	"os/exec"
-
 	"github.com/tailscale/wireguard-go/device"
 	"github.com/tailscale/wireguard-go/tun"
-	"inet.af/netaddr"
 	"tailscale.com/types/logger"
 )
 
@@ -21,139 +15,6 @@ import (
 // Work is currently underway for an in-kernel FreeBSD implementation of wireguard
 // https://svnweb.freebsd.org/base?view=revision&revision=357986
 
-type freebsdRouter struct {
-	logf    logger.Logf
-	tunname string
-	local   netaddr.IPPrefix
-	routes  map[netaddr.IPPrefix]struct{}
-}
-
 func newUserspaceRouter(logf logger.Logf, _ *device.Device, tundev tun.Device) (Router, error) {
-	tunname, err := tundev.Name()
+	return newUserspaceBSDRouter(logf, nil, tundev)
-	if err != nil {
-		return nil, err
-	}
-	return &freebsdRouter{
-		logf:    logf,
-		tunname: tunname,
-	}, nil
 }
-
-func cmd(args ...string) *exec.Cmd {
-	if len(args) == 0 {
-		log.Fatalf("exec.Cmd(%#v) invalid; need argv[0]\n", args)
-	}
-	return exec.Command(args[0], args[1:]...)
-}
-
-func (r *freebsdRouter) Up() error {
-	ifup := []string{"ifconfig", r.tunname, "up"}
-	if out, err := cmd(ifup...).CombinedOutput(); err != nil {
-		r.logf("running ifconfig failed: %v\n%s", err, out)
-		return err
-	}
-	return nil
-}
-
-func (r *freebsdRouter) Set(cfg *Config) error {
-	if cfg == nil {
-		cfg = &shutdownConfig
-	}
-	if len(cfg.LocalAddrs) == 0 {
-		return nil
-	}
-	// TODO: support configuring multiple local addrs on interface.
-	if len(cfg.LocalAddrs) != 1 {
-		return errors.New("freebsd doesn't support setting multiple local addrs yet")
-	}
-	localAddr := cfg.LocalAddrs[0]
-
-	var errq error
-
-	// Update the address.
-	if localAddr != r.local {
-		// If the interface is already set, remove it.
-		if r.local != (netaddr.IPPrefix{}) {
-			addrdel := []string{"ifconfig", r.tunname,
-				"inet", r.local.String(), "-alias"}
-			out, err := cmd(addrdel...).CombinedOutput()
-			if err != nil {
-				r.logf("addr del failed: %v: %v\n%s", addrdel, err, out)
-				if errq == nil {
-					errq = err
-				}
-			}
-		}
-
-		// Add the interface.
-		addradd := []string{"ifconfig", r.tunname,
-			"inet", localAddr.String(), localAddr.IP.String()}
-		out, err := cmd(addradd...).CombinedOutput()
-		if err != nil {
-			r.logf("addr add failed: %v: %v\n%s", addradd, err, out)
-			if errq == nil {
-				errq = err
-			}
-		}
-	}
-
-	newRoutes := make(map[netaddr.IPPrefix]struct{})
-	for _, route := range cfg.Routes {
-		newRoutes[route] = struct{}{}
-	}
-	// Delete any pre-existing routes.
-	for route := range r.routes {
-		if _, keep := newRoutes[route]; !keep {
-			net := route.IPNet()
-			nip := net.IP.Mask(net.Mask)
-			nstr := fmt.Sprintf("%v/%d", nip, route.Bits)
-			routedel := []string{"route", "-q", "-n",
-				"del", "-inet", nstr,
-				"-iface", r.tunname}
-			out, err := cmd(routedel...).CombinedOutput()
-			if err != nil {
-				r.logf("route del failed: %v: %v\n%s", routedel, err, out)
-				if errq == nil {
-					errq = err
-				}
-			}
-		}
-	}
-	// Add the routes.
-	for route := range newRoutes {
-		if _, exists := r.routes[route]; !exists {
-			net := route.IPNet()
-			nip := net.IP.Mask(net.Mask)
-			nstr := fmt.Sprintf("%v/%d", nip, route.Bits)
-			routeadd := []string{"route", "-q", "-n",
-				"add", "-inet", nstr,
-				"-iface", r.tunname}
-			out, err := cmd(routeadd...).CombinedOutput()
-			if err != nil {
-				r.logf("addr add failed: %v: %v\n%s", routeadd, err, out)
-				if errq == nil {
-					errq = err
-				}
-			}
-		}
-	}
-
-	// Store the interface and routes so we know what to change on an update.
-	r.local = localAddr
-	r.routes = newRoutes
-
-	if err := r.replaceResolvConf(cfg.DNS, cfg.DNSDomains); err != nil {
-		errq = fmt.Errorf("replacing resolv.conf failed: %v", err)
-	}
-
-	return errq
-}
-
-func (r *freebsdRouter) Close() error {
-	return nil
-}
-
-// TODO(mbaillie): these are no-ops for now. They could re-use the Linux funcs
-// (sans systemd parts), but I note Linux DNS is disabled(?) so leaving for now.
-func (r *freebsdRouter) replaceResolvConf(_ []netaddr.IP, _ []string) error { return nil }
-func (r *freebsdRouter) restoreResolvConf() error                           { return nil }

wgengine/router/router_userspace_bsd.go

@@ -0,0 +1,156 @@
+// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build darwin freebsd
+
+package router
+
+import (
+	"errors"
+	"fmt"
+	"log"
+	"os/exec"
+
+	"github.com/tailscale/wireguard-go/device"
+	"github.com/tailscale/wireguard-go/tun"
+	"inet.af/netaddr"
+	"tailscale.com/types/logger"
+)
+
+type userspaceBSDRouter struct {
+	logf    logger.Logf
+	tunname string
+	local   netaddr.IPPrefix
+	routes  map[netaddr.IPPrefix]struct{}
+}
+
+func newUserspaceBSDRouter(logf logger.Logf, _ *device.Device, tundev tun.Device) (Router, error) {
+	tunname, err := tundev.Name()
+	if err != nil {
+		return nil, err
+	}
+	return &userspaceBSDRouter{
+		logf:    logf,
+		tunname: tunname,
+	}, nil
+}
+
+func (r *userspaceBSDRouter) cmd(args ...string) *exec.Cmd {
+	if len(args) == 0 {
+		log.Fatalf("exec.Cmd(%#v) invalid; need argv[0]\n", args)
+	}
+	return exec.Command(args[0], args[1:]...)
+}
+
+func (r *userspaceBSDRouter) Up() error {
+	ifup := []string{"ifconfig", r.tunname, "up"}
+	if out, err := r.cmd(ifup...).CombinedOutput(); err != nil {
+		r.logf("running ifconfig failed: %v\n%s", err, out)
+		return err
+	}
+	return nil
+}
+
+func (r *userspaceBSDRouter) Set(cfg *Config) error {
+	if cfg == nil {
+		cfg = &shutdownConfig
+	}
+	if len(cfg.LocalAddrs) == 0 {
+		return nil
+	}
+	// TODO: support configuring multiple local addrs on interface.
+	if len(cfg.LocalAddrs) != 1 {
+		return errors.New("freebsd doesn't support setting multiple local addrs yet")
+	}
+	localAddr := cfg.LocalAddrs[0]
+
+	var errq error
+
+	// Update the address.
+	if localAddr != r.local {
+		// If the interface is already set, remove it.
+		if r.local != (netaddr.IPPrefix{}) {
+			addrdel := []string{"ifconfig", r.tunname,
+				"inet", r.local.String(), "-alias"}
+			out, err := r.cmd(addrdel...).CombinedOutput()
+			if err != nil {
+				r.logf("addr del failed: %v: %v\n%s", addrdel, err, out)
+				if errq == nil {
+					errq = err
+				}
+			}
+		}
+
+		// Add the interface.
+		addradd := []string{"ifconfig", r.tunname,
+			"inet", localAddr.String(), localAddr.IP.String()}
+		out, err := r.cmd(addradd...).CombinedOutput()
+		if err != nil {
+			r.logf("addr add failed: %v: %v\n%s", addradd, err, out)
+			if errq == nil {
+				errq = err
+			}
+		}
+	}
+
+	newRoutes := make(map[netaddr.IPPrefix]struct{})
+	for _, route := range cfg.Routes {
+		newRoutes[route] = struct{}{}
+	}
+	// Delete any pre-existing routes.
+	for route := range r.routes {
+		if _, keep := newRoutes[route]; !keep {
+			net := route.IPNet()
+			nip := net.IP.Mask(net.Mask)
+			nstr := fmt.Sprintf("%v/%d", nip, route.Bits)
+			routedel := []string{"route", "-q", "-n",
+				"del", "-inet", nstr,
+				"-iface", r.tunname}
+			out, err := r.cmd(routedel...).CombinedOutput()
+			if err != nil {
+				r.logf("route del failed: %v: %v\n%s", routedel, err, out)
+				if errq == nil {
+					errq = err
+				}
+			}
+		}
+	}
+	// Add the routes.
+	for route := range newRoutes {
+		if _, exists := r.routes[route]; !exists {
+			net := route.IPNet()
+			nip := net.IP.Mask(net.Mask)
+			nstr := fmt.Sprintf("%v/%d", nip, route.Bits)
+			routeadd := []string{"route", "-q", "-n",
+				"add", "-inet", nstr,
+				"-iface", r.tunname}
+			out, err := r.cmd(routeadd...).CombinedOutput()
+			if err != nil {
+				r.logf("addr add failed: %v: %v\n%s", routeadd, err, out)
+				if errq == nil {
+					errq = err
+				}
+			}
+		}
+	}
+
+	// Store the interface and routes so we know what to change on an update.
+	r.local = localAddr
+	r.routes = newRoutes
+
+	if err := r.replaceResolvConf(cfg.DNS, cfg.DNSDomains); err != nil {
+		errq = fmt.Errorf("replacing resolv.conf failed: %v", err)
+	}
+
+	return errq
+}
+
+func (r *userspaceBSDRouter) Close() error {
+	return nil
+}
+
+// TODO(mbaillie): these are no-ops for now. They could re-use the Linux funcs
+// (sans systemd parts), but I note Linux DNS is disabled(?) so leaving for now.
+func (r *userspaceBSDRouter) replaceResolvConf(_ []netaddr.IP, _ []string) error { return nil }
+func (r *userspaceBSDRouter) restoreResolvConf() error                           { return nil }