chore(all): make code compilable for other platforms than Linux

internal/routing/default.go

@@ -6,7 +6,6 @@ import (
 	"net/netip"
 
 	"github.com/qdm12/gluetun/internal/netlink"
-	"golang.org/x/sys/unix"
 )
 
 var ErrRouteDefaultNotFound = errors.New("default route not found")
@@ -30,7 +29,7 @@ func (r *Routing) DefaultRoutes() (defaultRoutes []DefaultRoute, err error) {
 	}
 
 	for _, route := range routes {
-		if route.Table != unix.RT_TABLE_MAIN {
+		if route.Table != tableMain {
 			// ignore non-main table
 			continue
 		}

internal/routing/local.go

@@ -6,7 +6,6 @@ import (
 	"net/netip"
 
 	"github.com/qdm12/gluetun/internal/netlink"
-	"golang.org/x/sys/unix"
 )
 
 var (
@@ -48,7 +47,7 @@ func (r *Routing) LocalNetworks() (localNetworks []LocalNetwork, err error) {
 	}
 
 	for _, route := range routes {
-		if route.Table != unix.RT_TABLE_MAIN ||
+		if route.Table != tableMain ||
 			(route.Gw.IsValid() && !route.Gw.IsUnspecified()) ||
 			(route.Dst.IsValid() && route.Dst.Addr().IsUnspecified()) {
 			continue

internal/routing/tables_linux.go

@@ -0,0 +1,8 @@
+package routing
+
+import "golang.org/x/sys/unix"
+
+const (
+	tableMain  = unix.RT_TABLE_MAIN
+	tableLocal = unix.RT_TABLE_LOCAL
+)

internal/routing/tables_unspecified.go

@@ -0,0 +1,8 @@
+//go:build !linux
+
+package routing
+
+const (
+	tableMain  = 0
+	tableLocal = 0
+)

internal/routing/vpn.go

@@ -6,7 +6,6 @@ import (
 	"net/netip"
 
 	"github.com/qdm12/gluetun/internal/netlink"
-	"golang.org/x/sys/unix"
 )
 
 var (
@@ -35,7 +34,7 @@ func (r *Routing) VPNLocalGatewayIP(vpnIntf string) (ip netip.Addr, err error) {
 			return route.Gw, nil
 		case route.Dst.IsSingleIP() &&
 			route.Dst.Addr().Compare(route.Src) == 0 &&
-			route.Table == unix.RT_TABLE_LOCAL: // Wireguard
+			route.Table == tableLocal: // Wireguard
 			route.Src = route.Src.Unmap()
 			if route.Src.Is6() {
 				return netip.Addr{}, fmt.Errorf("%w: %s", ErrVPNLocalGatewayIPv6NotSupported, route.Src)