wgengine: create freebsd-specific implementation

Signed-off-by: wardn <wardn@users.noreply.github.com>

wgengine/router_freebsd.go

@@ -0,0 +1,158 @@
+// 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.
+
+package wgengine
+
+import (
+	"fmt"
+	"log"
+	"net"
+	"os/exec"
+
+	"github.com/tailscale/wireguard-go/device"
+	"github.com/tailscale/wireguard-go/tun"
+	"github.com/tailscale/wireguard-go/wgcfg"
+	"tailscale.com/types/logger"
+)
+
+// For now this router only supports the userspace WireGuard implementations.
+//
+// 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   wgcfg.CIDR
+	routes  map[wgcfg.CIDR]struct{}
+}
+
+func newUserspaceRouter(logf logger.Logf, _ *device.Device, tundev tun.Device) (Router, error) {
+	tunname, err := tundev.Name()
+	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) SetRoutes(rs RouteSettings) error {
+	var errq error
+
+	// Update the address.
+	if rs.LocalAddr != r.local {
+		// If the interface is already set, remove it.
+		if r.local != (wgcfg.CIDR{}) {
+			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", rs.LocalAddr.String(), rs.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[wgcfg.CIDR]struct{})
+	for _, peer := range rs.Cfg.Peers {
+		for _, route := range peer.AllowedIPs {
+			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.Mask)
+			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.Mask)
+			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 = rs.LocalAddr
+	r.routes = newRoutes
+
+	if err := r.replaceResolvConf(rs.DNS, rs.DNSDomains); err != nil {
+		errq = fmt.Errorf("replacing resolv.conf failed: %v", err)
+	}
+
+	return errq
+}
+
+func (r *freebsdRouter) Close() error {
+	out, err := cmd("ifconfig", r.tunname, "down").CombinedOutput()
+	if err != nil {
+		r.logf("running ifconfig failed: %v\n%s", err, out)
+	}
+
+	if err := r.restoreResolvConf(); err != nil {
+		r.logf("failed to restore system resolv.conf: %v", err)
+	}
+
+	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(_ []net.IP, _ []string) error { return nil }
+func (r *freebsdRouter) restoreResolvConf() error                       { return nil }

wgengine/router_openbsd.go

@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build openbsd freebsd
-
 package wgengine
 
 import (
@@ -27,7 +25,7 @@
 // `ifstated(8)`/`devd(8)`, or become possible with the OpenBSD kernel
 // implementation. This merits further investigation.
 
-type bsdRouter struct {
+type openbsdRouter struct {
 	logf    logger.Logf
 	tunname string
 	local   wgcfg.CIDR
@@ -39,7 +37,7 @@ func newUserspaceRouter(logf logger.Logf, _ *device.Device, tundev tun.Device) (
 	if err != nil {
 		return nil, err
 	}
-	return &bsdRouter{
+	return &openbsdRouter{
 		logf:    logf,
 		tunname: tunname,
 	}, nil
@@ -53,7 +51,7 @@ func cmd(args ...string) *exec.Cmd {
 	return exec.Command(args[0], args[1:]...)
 }
 
-func (r *bsdRouter) Up() error {
+func (r *openbsdRouter) 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)
@@ -62,7 +60,7 @@ func (r *bsdRouter) Up() error {
 	return nil
 }
 
-func (r *bsdRouter) SetRoutes(rs RouteSettings) error {
+func (r *openbsdRouter) SetRoutes(rs RouteSettings) error {
 	var errq error
 
 	if rs.LocalAddr != r.local {
@@ -160,7 +158,7 @@ func (r *bsdRouter) SetRoutes(rs RouteSettings) error {
 	return errq
 }
 
-func (r *bsdRouter) Close() error {
+func (r *openbsdRouter) Close() error {
 	out, err := cmd("ifconfig", r.tunname, "down").CombinedOutput()
 	if err != nil {
 		r.logf("running ifconfig failed: %v\n%s", err, out)
@@ -177,5 +175,5 @@ func (r *bsdRouter) Close() error {
 
 // 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 *bsdRouter) replaceResolvConf(_ []net.IP, _ []string) error { return nil }
-func (r *bsdRouter) restoreResolvConf() error                       { return nil }
+func (r *openbsdRouter) replaceResolvConf(_ []net.IP, _ []string) error { return nil }
+func (r *openbsdRouter) restoreResolvConf() error                       { return nil }