Linux legacy routing (#1774)

* Add Linux legacy routing if ip rule functionality is not available

* Ignore exclusion route errors if host has no route

* Exclude iOS from route manager

* Also retrieve IPv6 routes

* Ignore loopback addresses not being in the main table

* Ignore "not supported" errors on cleanup

* Fix regression in ListenUDP not using fwmarks

client/internal/routemanager/routemanager.go

@@ -1,8 +1,9 @@
-//go:build !android
+//go:build !android && !ios
 
 package routemanager
 
 import (
+	"errors"
 	"fmt"
 	"net/netip"
 	"sync"
@@ -53,6 +54,9 @@ func (rm *RouteManager) AddRouteRef(connID nbnet.ConnectionID, prefix netip.Pref
 	if ref.count == 0 {
 		log.Debugf("Adding route for prefix %s", prefix)
 		nexthop, intf, err := rm.addRoute(prefix)
+		if errors.Is(err, errRouteNotFound) {
+			return nil
+		}
 		if err != nil {
 			return fmt.Errorf("failed to add route for prefix %s: %w", prefix, err)
 		}

client/internal/routemanager/systemops.go

@@ -0,0 +1,410 @@
+//go:build !android && !ios
+
+package routemanager
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"net"
+	"net/netip"
+
+	"github.com/hashicorp/go-multierror"
+	"github.com/libp2p/go-netroute"
+	log "github.com/sirupsen/logrus"
+
+	"github.com/netbirdio/netbird/client/internal/peer"
+	"github.com/netbirdio/netbird/iface"
+	nbnet "github.com/netbirdio/netbird/util/net"
+)
+
+var splitDefaultv4_1 = netip.PrefixFrom(netip.IPv4Unspecified(), 1)
+var splitDefaultv4_2 = netip.PrefixFrom(netip.AddrFrom4([4]byte{128}), 1)
+var splitDefaultv6_1 = netip.PrefixFrom(netip.IPv6Unspecified(), 1)
+var splitDefaultv6_2 = netip.PrefixFrom(netip.AddrFrom16([16]byte{0x80}), 1)
+
+var errRouteNotFound = fmt.Errorf("route not found")
+
+// TODO: fix: for default our wg address now appears as the default gw
+func addRouteForCurrentDefaultGateway(prefix netip.Prefix) error {
+	addr := netip.IPv4Unspecified()
+	if prefix.Addr().Is6() {
+		addr = netip.IPv6Unspecified()
+	}
+
+	defaultGateway, _, err := getNextHop(addr)
+	if err != nil && !errors.Is(err, errRouteNotFound) {
+		return fmt.Errorf("get existing route gateway: %s", err)
+	}
+
+	if !prefix.Contains(defaultGateway) {
+		log.Debugf("Skipping adding a new route for gateway %s because it is not in the network %s", defaultGateway, prefix)
+		return nil
+	}
+
+	gatewayPrefix := netip.PrefixFrom(defaultGateway, 32)
+	if defaultGateway.Is6() {
+		gatewayPrefix = netip.PrefixFrom(defaultGateway, 128)
+	}
+
+	ok, err := existsInRouteTable(gatewayPrefix)
+	if err != nil {
+		return fmt.Errorf("unable to check if there is an existing route for gateway %s. error: %s", gatewayPrefix, err)
+	}
+
+	if ok {
+		log.Debugf("Skipping adding a new route for gateway %s because it already exists", gatewayPrefix)
+		return nil
+	}
+
+	var exitIntf string
+	gatewayHop, intf, err := getNextHop(defaultGateway)
+	if err != nil && !errors.Is(err, errRouteNotFound) {
+		return fmt.Errorf("unable to get the next hop for the default gateway address. error: %s", err)
+	}
+	if intf != nil {
+		exitIntf = intf.Name
+	}
+
+	log.Debugf("Adding a new route for gateway %s with next hop %s", gatewayPrefix, gatewayHop)
+	return addToRouteTable(gatewayPrefix, gatewayHop, exitIntf)
+}
+
+func getNextHop(ip netip.Addr) (netip.Addr, *net.Interface, error) {
+	r, err := netroute.New()
+	if err != nil {
+		return netip.Addr{}, nil, fmt.Errorf("new netroute: %w", err)
+	}
+	intf, gateway, preferredSrc, err := r.Route(ip.AsSlice())
+	if err != nil {
+		log.Warnf("Failed to get route for %s: %v", ip, err)
+		return netip.Addr{}, nil, errRouteNotFound
+	}
+
+	log.Debugf("Route for %s: interface %v, nexthop %v, preferred source %v", ip, intf, gateway, preferredSrc)
+	if gateway == nil {
+		if preferredSrc == nil {
+			return netip.Addr{}, nil, errRouteNotFound
+		}
+		log.Debugf("No next hop found for ip %s, using preferred source %s", ip, preferredSrc)
+
+		addr, ok := netip.AddrFromSlice(preferredSrc)
+		if !ok {
+			return netip.Addr{}, nil, fmt.Errorf("failed to parse IP address: %s", preferredSrc)
+		}
+		return addr.Unmap(), intf, nil
+	}
+
+	addr, ok := netip.AddrFromSlice(gateway)
+	if !ok {
+		return netip.Addr{}, nil, fmt.Errorf("failed to parse IP address: %s", gateway)
+	}
+
+	return addr.Unmap(), intf, nil
+}
+
+func existsInRouteTable(prefix netip.Prefix) (bool, error) {
+	routes, err := getRoutesFromTable()
+	if err != nil {
+		return false, fmt.Errorf("get routes from table: %w", err)
+	}
+	for _, tableRoute := range routes {
+		if tableRoute == prefix {
+			return true, nil
+		}
+	}
+	return false, nil
+}
+
+func isSubRange(prefix netip.Prefix) (bool, error) {
+	routes, err := getRoutesFromTable()
+	if err != nil {
+		return false, fmt.Errorf("get routes from table: %w", err)
+	}
+	for _, tableRoute := range routes {
+		if tableRoute.Bits() > minRangeBits && tableRoute.Contains(prefix.Addr()) && tableRoute.Bits() < prefix.Bits() {
+			return true, nil
+		}
+	}
+	return false, nil
+}
+
+// getRouteToNonVPNIntf returns the next hop and interface for the given prefix.
+// If the next hop or interface is pointing to the VPN interface, it will return an error
+func addRouteToNonVPNIntf(
+	prefix netip.Prefix,
+	vpnIntf *iface.WGIface,
+	initialNextHop netip.Addr,
+	initialIntf *net.Interface,
+) (netip.Addr, string, error) {
+	addr := prefix.Addr()
+	switch {
+	case addr.IsLoopback():
+		return netip.Addr{}, "", fmt.Errorf("adding route for loopback address %s is not allowed", prefix)
+	case addr.IsLinkLocalUnicast():
+		return netip.Addr{}, "", fmt.Errorf("adding route for link-local unicast address %s is not allowed", prefix)
+	case addr.IsLinkLocalMulticast():
+		return netip.Addr{}, "", fmt.Errorf("adding route for link-local multicast address %s is not allowed", prefix)
+	case addr.IsInterfaceLocalMulticast():
+		return netip.Addr{}, "", fmt.Errorf("adding route for interface-local multicast address %s is not allowed", prefix)
+	case addr.IsUnspecified():
+		return netip.Addr{}, "", fmt.Errorf("adding route for unspecified address %s is not allowed", prefix)
+	case addr.IsMulticast():
+		return netip.Addr{}, "", fmt.Errorf("adding route for multicast address %s is not allowed", prefix)
+	}
+
+	// Determine the exit interface and next hop for the prefix, so we can add a specific route
+	nexthop, intf, err := getNextHop(addr)
+	if err != nil {
+		return netip.Addr{}, "", fmt.Errorf("get next hop: %w", err)
+	}
+
+	log.Debugf("Found next hop %s for prefix %s with interface %v", nexthop, prefix, intf)
+	exitNextHop := nexthop
+	var exitIntf string
+	if intf != nil {
+		exitIntf = intf.Name
+	}
+
+	vpnAddr, ok := netip.AddrFromSlice(vpnIntf.Address().IP)
+	if !ok {
+		return netip.Addr{}, "", fmt.Errorf("failed to convert vpn address to netip.Addr")
+	}
+
+	// if next hop is the VPN address or the interface is the VPN interface, we should use the initial values
+	if exitNextHop == vpnAddr || exitIntf == vpnIntf.Name() {
+		log.Debugf("Route for prefix %s is pointing to the VPN interface", prefix)
+		exitNextHop = initialNextHop
+		if initialIntf != nil {
+			exitIntf = initialIntf.Name
+		}
+	}
+
+	log.Debugf("Adding a new route for prefix %s with next hop %s", prefix, exitNextHop)
+	if err := addToRouteTable(prefix, exitNextHop, exitIntf); err != nil {
+		return netip.Addr{}, "", fmt.Errorf("add route to table: %w", err)
+	}
+
+	return exitNextHop, exitIntf, nil
+}
+
+// genericAddVPNRoute adds a new route to the vpn interface, it splits the default prefix
+// in two /1 prefixes to avoid replacing the existing default route
+func genericAddVPNRoute(prefix netip.Prefix, intf string) error {
+	if prefix == defaultv4 {
+		if err := addToRouteTable(splitDefaultv4_1, netip.Addr{}, intf); err != nil {
+			return err
+		}
+		if err := addToRouteTable(splitDefaultv4_2, netip.Addr{}, intf); err != nil {
+			if err2 := removeFromRouteTable(splitDefaultv4_1, netip.Addr{}, intf); err2 != nil {
+				log.Warnf("Failed to rollback route addition: %s", err2)
+			}
+			return err
+		}
+
+		// TODO: remove once IPv6 is supported on the interface
+		if err := addToRouteTable(splitDefaultv6_1, netip.Addr{}, intf); err != nil {
+			return fmt.Errorf("add unreachable route split 1: %w", err)
+		}
+		if err := addToRouteTable(splitDefaultv6_2, netip.Addr{}, intf); err != nil {
+			if err2 := removeFromRouteTable(splitDefaultv6_1, netip.Addr{}, intf); err2 != nil {
+				log.Warnf("Failed to rollback route addition: %s", err2)
+			}
+			return fmt.Errorf("add unreachable route split 2: %w", err)
+		}
+
+		return nil
+	} else if prefix == defaultv6 {
+		if err := addToRouteTable(splitDefaultv6_1, netip.Addr{}, intf); err != nil {
+			return fmt.Errorf("add unreachable route split 1: %w", err)
+		}
+		if err := addToRouteTable(splitDefaultv6_2, netip.Addr{}, intf); err != nil {
+			if err2 := removeFromRouteTable(splitDefaultv6_1, netip.Addr{}, intf); err2 != nil {
+				log.Warnf("Failed to rollback route addition: %s", err2)
+			}
+			return fmt.Errorf("add unreachable route split 2: %w", err)
+		}
+
+		return nil
+	}
+
+	return addNonExistingRoute(prefix, intf)
+}
+
+// addNonExistingRoute adds a new route to the vpn interface if it doesn't exist in the current routing table
+func addNonExistingRoute(prefix netip.Prefix, intf string) error {
+	ok, err := existsInRouteTable(prefix)
+	if err != nil {
+		return fmt.Errorf("exists in route table: %w", err)
+	}
+	if ok {
+		log.Warnf("Skipping adding a new route for network %s because it already exists", prefix)
+		return nil
+	}
+
+	ok, err = isSubRange(prefix)
+	if err != nil {
+		return fmt.Errorf("sub range: %w", err)
+	}
+
+	if ok {
+		err := addRouteForCurrentDefaultGateway(prefix)
+		if err != nil {
+			log.Warnf("Unable to add route for current default gateway route. Will proceed without it. error: %s", err)
+		}
+	}
+
+	return addToRouteTable(prefix, netip.Addr{}, intf)
+}
+
+// genericRemoveVPNRoute removes the route from the vpn interface. If a default prefix is given,
+// it will remove the split /1 prefixes
+func genericRemoveVPNRoute(prefix netip.Prefix, intf string) error {
+	if prefix == defaultv4 {
+		var result *multierror.Error
+		if err := removeFromRouteTable(splitDefaultv4_1, netip.Addr{}, intf); err != nil {
+			result = multierror.Append(result, err)
+		}
+		if err := removeFromRouteTable(splitDefaultv4_2, netip.Addr{}, intf); err != nil {
+			result = multierror.Append(result, err)
+		}
+
+		// TODO: remove once IPv6 is supported on the interface
+		if err := removeFromRouteTable(splitDefaultv6_1, netip.Addr{}, intf); err != nil {
+			result = multierror.Append(result, err)
+		}
+		if err := removeFromRouteTable(splitDefaultv6_2, netip.Addr{}, intf); err != nil {
+			result = multierror.Append(result, err)
+		}
+
+		return result.ErrorOrNil()
+	} else if prefix == defaultv6 {
+		var result *multierror.Error
+		if err := removeFromRouteTable(splitDefaultv6_1, netip.Addr{}, intf); err != nil {
+			result = multierror.Append(result, err)
+		}
+		if err := removeFromRouteTable(splitDefaultv6_2, netip.Addr{}, intf); err != nil {
+			result = multierror.Append(result, err)
+		}
+
+		return result.ErrorOrNil()
+	}
+
+	return removeFromRouteTable(prefix, netip.Addr{}, intf)
+}
+
+func getPrefixFromIP(ip net.IP) (*netip.Prefix, error) {
+	addr, ok := netip.AddrFromSlice(ip)
+	if !ok {
+		return nil, fmt.Errorf("parse IP address: %s", ip)
+	}
+	addr = addr.Unmap()
+
+	var prefixLength int
+	switch {
+	case addr.Is4():
+		prefixLength = 32
+	case addr.Is6():
+		prefixLength = 128
+	default:
+		return nil, fmt.Errorf("invalid IP address: %s", addr)
+	}
+
+	prefix := netip.PrefixFrom(addr, prefixLength)
+	return &prefix, nil
+}
+
+func setupRoutingWithRouteManager(routeManager **RouteManager, initAddresses []net.IP, wgIface *iface.WGIface) (peer.BeforeAddPeerHookFunc, peer.AfterRemovePeerHookFunc, error) {
+	initialNextHopV4, initialIntfV4, err := getNextHop(netip.IPv4Unspecified())
+	if err != nil && !errors.Is(err, errRouteNotFound) {
+		log.Errorf("Unable to get initial v4 default next hop: %v", err)
+	}
+	initialNextHopV6, initialIntfV6, err := getNextHop(netip.IPv6Unspecified())
+	if err != nil && !errors.Is(err, errRouteNotFound) {
+		log.Errorf("Unable to get initial v6 default next hop: %v", err)
+	}
+
+	*routeManager = NewRouteManager(
+		func(prefix netip.Prefix) (netip.Addr, string, error) {
+			addr := prefix.Addr()
+			nexthop, intf := initialNextHopV4, initialIntfV4
+			if addr.Is6() {
+				nexthop, intf = initialNextHopV6, initialIntfV6
+			}
+			return addRouteToNonVPNIntf(prefix, wgIface, nexthop, intf)
+		},
+		removeFromRouteTable,
+	)
+
+	return setupHooks(*routeManager, initAddresses)
+}
+
+func cleanupRoutingWithRouteManager(routeManager *RouteManager) error {
+	if routeManager == nil {
+		return nil
+	}
+
+	// TODO: Remove hooks selectively
+	nbnet.RemoveDialerHooks()
+	nbnet.RemoveListenerHooks()
+
+	if err := routeManager.Flush(); err != nil {
+		return fmt.Errorf("flush route manager: %w", err)
+	}
+
+	return nil
+}
+
+func setupHooks(routeManager *RouteManager, initAddresses []net.IP) (peer.BeforeAddPeerHookFunc, peer.AfterRemovePeerHookFunc, error) {
+	beforeHook := func(connID nbnet.ConnectionID, ip net.IP) error {
+		prefix, err := getPrefixFromIP(ip)
+		if err != nil {
+			return fmt.Errorf("convert ip to prefix: %w", err)
+		}
+
+		if err := routeManager.AddRouteRef(connID, *prefix); err != nil {
+			return fmt.Errorf("adding route reference: %v", err)
+		}
+
+		return nil
+	}
+	afterHook := func(connID nbnet.ConnectionID) error {
+		if err := routeManager.RemoveRouteRef(connID); err != nil {
+			return fmt.Errorf("remove route reference: %w", err)
+		}
+
+		return nil
+	}
+
+	for _, ip := range initAddresses {
+		if err := beforeHook("init", ip); err != nil {
+			log.Errorf("Failed to add route reference: %v", err)
+		}
+	}
+
+	nbnet.AddDialerHook(func(ctx context.Context, connID nbnet.ConnectionID, resolvedIPs []net.IPAddr) error {
+		if ctx.Err() != nil {
+			return ctx.Err()
+		}
+
+		var result *multierror.Error
+		for _, ip := range resolvedIPs {
+			result = multierror.Append(result, beforeHook(connID, ip.IP))
+		}
+		return result.ErrorOrNil()
+	})
+
+	nbnet.AddDialerCloseHook(func(connID nbnet.ConnectionID, conn *net.Conn) error {
+		return afterHook(connID)
+	})
+
+	nbnet.AddListenerWriteHook(func(connID nbnet.ConnectionID, ip *net.IPAddr, data []byte) error {
+		return beforeHook(connID, ip.IP)
+	})
+
+	nbnet.AddListenerCloseHook(func(connID nbnet.ConnectionID, conn net.PacketConn) error {
+		return afterHook(connID)
+	})
+
+	return beforeHook, afterHook, nil
+}

client/internal/routemanager/systemops_linux.go

@@ -35,6 +35,9 @@ const (
 
 var ErrTableIDExists = errors.New("ID exists with different name")
 
+var routeManager = &RouteManager{}
+var isLegacy = os.Getenv("NB_USE_LEGACY_ROUTING") == "true"
+
 type ruleParams struct {
 	fwmark         int
 	tableID        int
@@ -66,7 +69,12 @@ func getSetupRules() []ruleParams {
 // enabling VPN connectivity.
 //
 // The rules are inserted in reverse order, as rules are added from the bottom up in the rule list.
-func setupRouting([]net.IP, *iface.WGIface) (_ peer.BeforeAddPeerHookFunc, _ peer.AfterRemovePeerHookFunc, err error) {
+func setupRouting(initAddresses []net.IP, wgIface *iface.WGIface) (_ peer.BeforeAddPeerHookFunc, _ peer.AfterRemovePeerHookFunc, err error) {
+	if isLegacy {
+		log.Infof("Using legacy routing setup")
+		return setupRoutingWithRouteManager(&routeManager, initAddresses, wgIface)
+	}
+
 	if err = addRoutingTableName(); err != nil {
 		log.Errorf("Error adding routing table name: %v", err)
 	}
@@ -82,6 +90,11 @@ func setupRouting([]net.IP, *iface.WGIface) (_ peer.BeforeAddPeerHookFunc, _ pee
 	rules := getSetupRules()
 	for _, rule := range rules {
 		if err := addRule(rule); err != nil {
+			if errors.Is(err, syscall.EOPNOTSUPP) {
+				log.Warnf("Rule operations are not supported, falling back to the legacy routing setup")
+				isLegacy = true
+				return setupRoutingWithRouteManager(&routeManager, initAddresses, wgIface)
+			}
 			return nil, nil, fmt.Errorf("%s: %w", rule.description, err)
 		}
 	}
@@ -93,6 +106,10 @@ func setupRouting([]net.IP, *iface.WGIface) (_ peer.BeforeAddPeerHookFunc, _ pee
 // It systematically removes the three rules and any associated routing table entries to ensure a clean state.
 // The function uses error aggregation to report any errors encountered during the cleanup process.
 func cleanupRouting() error {
+	if isLegacy {
+		return cleanupRoutingWithRouteManager(routeManager)
+	}
+
 	var result *multierror.Error
 
 	if err := flushRoutes(NetbirdVPNTableID, netlink.FAMILY_V4); err != nil {
@@ -104,7 +121,7 @@ func cleanupRouting() error {
 
 	rules := getSetupRules()
 	for _, rule := range rules {
-		if err := removeAllRules(rule); err != nil {
+		if err := removeAllRules(rule); err != nil && !errors.Is(err, syscall.EOPNOTSUPP) {
 			result = multierror.Append(result, fmt.Errorf("%s: %w", rule.description, err))
 		}
 	}
@@ -112,49 +129,104 @@ func cleanupRouting() error {
 	return result.ErrorOrNil()
 }
 
+func addToRouteTable(prefix netip.Prefix, nexthop netip.Addr, intf string) error {
+	return addRoute(prefix, nexthop, intf, syscall.RT_TABLE_MAIN)
+}
+
+func removeFromRouteTable(prefix netip.Prefix, nexthop netip.Addr, intf string) error {
+	return removeRoute(prefix, nexthop, intf, syscall.RT_TABLE_MAIN)
+}
+
 func addVPNRoute(prefix netip.Prefix, intf string) error {
-	// No need to check if routes exist as main table takes precedence over the VPN table via Rule 2
+	if isLegacy {
+		return genericAddVPNRoute(prefix, intf)
+	}
+
+	// No need to check if routes exist as main table takes precedence over the VPN table via Rule 1
 
 	// TODO remove this once we have ipv6 support
 	if prefix == defaultv4 {
-		if err := addUnreachableRoute(&defaultv6, NetbirdVPNTableID, netlink.FAMILY_V6); err != nil {
+		if err := addUnreachableRoute(defaultv6, NetbirdVPNTableID); err != nil {
 			return fmt.Errorf("add blackhole: %w", err)
 		}
 	}
-	if err := addRoute(&prefix, nil, &intf, NetbirdVPNTableID, netlink.FAMILY_V4); err != nil {
+	if err := addRoute(prefix, netip.Addr{}, intf, NetbirdVPNTableID); err != nil {
 		return fmt.Errorf("add route: %w", err)
 	}
 	return nil
 }
 
 func removeVPNRoute(prefix netip.Prefix, intf string) error {
+	if isLegacy {
+		return genericRemoveVPNRoute(prefix, intf)
+	}
+
 	// TODO remove this once we have ipv6 support
 	if prefix == defaultv4 {
-		if err := removeUnreachableRoute(&defaultv6, NetbirdVPNTableID, netlink.FAMILY_V6); err != nil {
+		if err := removeUnreachableRoute(defaultv6, NetbirdVPNTableID); err != nil {
 			return fmt.Errorf("remove unreachable route: %w", err)
 		}
 	}
-	if err := removeRoute(&prefix, nil, &intf, NetbirdVPNTableID, netlink.FAMILY_V4); err != nil {
+	if err := removeRoute(prefix, netip.Addr{}, intf, NetbirdVPNTableID); err != nil {
 		return fmt.Errorf("remove route: %w", err)
 	}
 	return nil
 }
 
+func getRoutesFromTable() ([]netip.Prefix, error) {
+	v4Routes, err := getRoutes(syscall.RT_TABLE_MAIN, netlink.FAMILY_V4)
+	if err != nil {
+		return nil, fmt.Errorf("get v4 routes: %w", err)
+	}
+	v6Routes, err := getRoutes(syscall.RT_TABLE_MAIN, netlink.FAMILY_V6)
+	if err != nil {
+		return nil, fmt.Errorf("get v6 routes: %w", err)
+
+	}
+	return append(v4Routes, v6Routes...), nil
+}
+
+// getRoutes fetches routes from a specific routing table identified by tableID.
+func getRoutes(tableID, family int) ([]netip.Prefix, error) {
+	var prefixList []netip.Prefix
+
+	routes, err := netlink.RouteListFiltered(family, &netlink.Route{Table: tableID}, netlink.RT_FILTER_TABLE)
+	if err != nil {
+		return nil, fmt.Errorf("list routes from table %d: %v", tableID, err)
+	}
+
+	for _, route := range routes {
+		if route.Dst != nil {
+			addr, ok := netip.AddrFromSlice(route.Dst.IP)
+			if !ok {
+				return nil, fmt.Errorf("parse route destination IP: %v", route.Dst.IP)
+			}
+
+			ones, _ := route.Dst.Mask.Size()
+
+			prefix := netip.PrefixFrom(addr, ones)
+			if prefix.IsValid() {
+				prefixList = append(prefixList, prefix)
+			}
+		}
+	}
+
+	return prefixList, nil
+}
+
 // addRoute adds a route to a specific routing table identified by tableID.
-func addRoute(prefix *netip.Prefix, addr, intf *string, tableID, family int) error {
+func addRoute(prefix netip.Prefix, addr netip.Addr, intf string, tableID int) error {
 	route := &netlink.Route{
 		Scope:  netlink.SCOPE_UNIVERSE,
 		Table:  tableID,
-		Family: family,
+		Family: getAddressFamily(prefix),
 	}
 
-	if prefix != nil {
 	_, ipNet, err := net.ParseCIDR(prefix.String())
 	if err != nil {
 		return fmt.Errorf("parse prefix %s: %w", prefix, err)
 	}
 	route.Dst = ipNet
-	}
 
 	if err := addNextHop(addr, intf, route); err != nil {
 		return fmt.Errorf("add gateway and device: %w", err)
@@ -170,7 +242,7 @@ func addRoute(prefix *netip.Prefix, addr, intf *string, tableID, family int) err
 // addUnreachableRoute adds an unreachable route for the specified IP family and routing table.
 // ipFamily should be netlink.FAMILY_V4 for IPv4 or netlink.FAMILY_V6 for IPv6.
 // tableID specifies the routing table to which the unreachable route will be added.
-func addUnreachableRoute(prefix *netip.Prefix, tableID, ipFamily int) error {
+func addUnreachableRoute(prefix netip.Prefix, tableID int) error {
 	_, ipNet, err := net.ParseCIDR(prefix.String())
 	if err != nil {
 		return fmt.Errorf("parse prefix %s: %w", prefix, err)
@@ -179,7 +251,7 @@ func addUnreachableRoute(prefix *netip.Prefix, tableID, ipFamily int) error {
 	route := &netlink.Route{
 		Type:   syscall.RTN_UNREACHABLE,
 		Table:  tableID,
-		Family: ipFamily,
+		Family: getAddressFamily(prefix),
 		Dst:    ipNet,
 	}
 
@@ -190,7 +262,7 @@ func addUnreachableRoute(prefix *netip.Prefix, tableID, ipFamily int) error {
 	return nil
 }
 
-func removeUnreachableRoute(prefix *netip.Prefix, tableID, ipFamily int) error {
+func removeUnreachableRoute(prefix netip.Prefix, tableID int) error {
 	_, ipNet, err := net.ParseCIDR(prefix.String())
 	if err != nil {
 		return fmt.Errorf("parse prefix %s: %w", prefix, err)
@@ -199,7 +271,7 @@ func removeUnreachableRoute(prefix *netip.Prefix, tableID, ipFamily int) error {
 	route := &netlink.Route{
 		Type:   syscall.RTN_UNREACHABLE,
 		Table:  tableID,
-		Family: ipFamily,
+		Family: getAddressFamily(prefix),
 		Dst:    ipNet,
 	}
 
@@ -212,7 +284,7 @@ func removeUnreachableRoute(prefix *netip.Prefix, tableID, ipFamily int) error {
 }
 
 // removeRoute removes a route from a specific routing table identified by tableID.
-func removeRoute(prefix *netip.Prefix, addr, intf *string, tableID, family int) error {
+func removeRoute(prefix netip.Prefix, addr netip.Addr, intf string, tableID int) error {
 	_, ipNet, err := net.ParseCIDR(prefix.String())
 	if err != nil {
 		return fmt.Errorf("parse prefix %s: %w", prefix, err)
@@ -221,7 +293,7 @@ func removeRoute(prefix *netip.Prefix, addr, intf *string, tableID, family int)
 	route := &netlink.Route{
 		Scope:  netlink.SCOPE_UNIVERSE,
 		Table:  tableID,
-		Family: family,
+		Family: getAddressFamily(prefix),
 		Dst:    ipNet,
 	}
 
@@ -392,23 +464,25 @@ func removeAllRules(params ruleParams) error {
 }
 
 // addNextHop adds the gateway and device to the route.
-func addNextHop(addr *string, intf *string, route *netlink.Route) error {
+func addNextHop(addr netip.Addr, intf string, route *netlink.Route) error {
-	if addr != nil {
+	if addr.IsValid() {
-		ip := net.ParseIP(*addr)
+		route.Gw = addr.AsSlice()
-		if ip == nil {
-			return fmt.Errorf("parsing address %s failed", *addr)
 	}
 
-		route.Gw = ip
+	if intf != "" {
-	}
+		link, err := netlink.LinkByName(intf)
-
-	if intf != nil {
-		link, err := netlink.LinkByName(*intf)
 		if err != nil {
-			return fmt.Errorf("set interface %s: %w", *intf, err)
+			return fmt.Errorf("set interface %s: %w", intf, err)
 		}
 		route.LinkIndex = link.Attrs().Index
 	}
 
 	return nil
 }
+
+func getAddressFamily(prefix netip.Prefix) int {
+	if prefix.Addr().Is4() {
+		return netlink.FAMILY_V4
+	}
+	return netlink.FAMILY_V6
+}

client/internal/routemanager/systemops_linux_test.go

@@ -21,8 +21,6 @@ var expectedLoopbackInt = "lo"
 var expectedExternalInt = "dummyext0"
 var expectedInternalInt = "dummyint0"
 
-var errRouteNotFound = fmt.Errorf("route not found")
-
 func init() {
 	testCases = append(testCases, []testCase{
 		{

client/internal/routemanager/systemops_nonlinux.go

@@ -3,414 +3,21 @@
 package routemanager
 
 import (
-	"context"
-	"errors"
-	"fmt"
-	"net"
 	"net/netip"
 	"runtime"
 
-	"github.com/hashicorp/go-multierror"
-	"github.com/libp2p/go-netroute"
 	log "github.com/sirupsen/logrus"
-
-	"github.com/netbirdio/netbird/client/internal/peer"
-	"github.com/netbirdio/netbird/iface"
-	nbnet "github.com/netbirdio/netbird/util/net"
 )
 
-var splitDefaultv4_1 = netip.PrefixFrom(netip.IPv4Unspecified(), 1)
-var splitDefaultv4_2 = netip.PrefixFrom(netip.AddrFrom4([4]byte{128}), 1)
-var splitDefaultv6_1 = netip.PrefixFrom(netip.IPv6Unspecified(), 1)
-var splitDefaultv6_2 = netip.PrefixFrom(netip.AddrFrom16([16]byte{0x80}), 1)
-
-var errRouteNotFound = fmt.Errorf("route not found")
-
 func enableIPForwarding() error {
 	log.Infof("Enable IP forwarding is not implemented on %s", runtime.GOOS)
 	return nil
 }
 
-// TODO: fix: for default our wg address now appears as the default gw
-func addRouteForCurrentDefaultGateway(prefix netip.Prefix) error {
-	addr := netip.IPv4Unspecified()
-	if prefix.Addr().Is6() {
-		addr = netip.IPv6Unspecified()
-	}
-
-	defaultGateway, _, err := getNextHop(addr)
-	if err != nil && !errors.Is(err, errRouteNotFound) {
-		return fmt.Errorf("get existing route gateway: %s", err)
-	}
-
-	if !prefix.Contains(defaultGateway) {
-		log.Debugf("Skipping adding a new route for gateway %s because it is not in the network %s", defaultGateway, prefix)
-		return nil
-	}
-
-	gatewayPrefix := netip.PrefixFrom(defaultGateway, 32)
-	if defaultGateway.Is6() {
-		gatewayPrefix = netip.PrefixFrom(defaultGateway, 128)
-	}
-
-	ok, err := existsInRouteTable(gatewayPrefix)
-	if err != nil {
-		return fmt.Errorf("unable to check if there is an existing route for gateway %s. error: %s", gatewayPrefix, err)
-	}
-
-	if ok {
-		log.Debugf("Skipping adding a new route for gateway %s because it already exists", gatewayPrefix)
-		return nil
-	}
-
-	var exitIntf string
-	gatewayHop, intf, err := getNextHop(defaultGateway)
-	if err != nil && !errors.Is(err, errRouteNotFound) {
-		return fmt.Errorf("unable to get the next hop for the default gateway address. error: %s", err)
-	}
-	if intf != nil {
-		exitIntf = intf.Name
-	}
-
-	log.Debugf("Adding a new route for gateway %s with next hop %s", gatewayPrefix, gatewayHop)
-	return addToRouteTable(gatewayPrefix, gatewayHop, exitIntf)
-}
-
-func getNextHop(ip netip.Addr) (netip.Addr, *net.Interface, error) {
-	r, err := netroute.New()
-	if err != nil {
-		return netip.Addr{}, nil, fmt.Errorf("new netroute: %w", err)
-	}
-	intf, gateway, preferredSrc, err := r.Route(ip.AsSlice())
-	if err != nil {
-		log.Errorf("Getting routes returned an error: %v", err)
-		return netip.Addr{}, nil, errRouteNotFound
-	}
-
-	log.Debugf("Route for %s: interface %v, nexthop %v, preferred source %v", ip, intf, gateway, preferredSrc)
-	if gateway == nil {
-		if preferredSrc == nil {
-			return netip.Addr{}, nil, errRouteNotFound
-		}
-		log.Debugf("No next hop found for ip %s, using preferred source %s", ip, preferredSrc)
-
-		addr, ok := netip.AddrFromSlice(preferredSrc)
-		if !ok {
-			return netip.Addr{}, nil, fmt.Errorf("failed to parse IP address: %s", preferredSrc)
-		}
-		return addr.Unmap(), intf, nil
-	}
-
-	addr, ok := netip.AddrFromSlice(gateway)
-	if !ok {
-		return netip.Addr{}, nil, fmt.Errorf("failed to parse IP address: %s", gateway)
-	}
-
-	return addr.Unmap(), intf, nil
-}
-
-func existsInRouteTable(prefix netip.Prefix) (bool, error) {
-	routes, err := getRoutesFromTable()
-	if err != nil {
-		return false, fmt.Errorf("get routes from table: %w", err)
-	}
-	for _, tableRoute := range routes {
-		if tableRoute == prefix {
-			return true, nil
-		}
-	}
-	return false, nil
-}
-
-func isSubRange(prefix netip.Prefix) (bool, error) {
-	routes, err := getRoutesFromTable()
-	if err != nil {
-		return false, fmt.Errorf("get routes from table: %w", err)
-	}
-	for _, tableRoute := range routes {
-		if tableRoute.Bits() > minRangeBits && tableRoute.Contains(prefix.Addr()) && tableRoute.Bits() < prefix.Bits() {
-			return true, nil
-		}
-	}
-	return false, nil
-}
-
-// getRouteToNonVPNIntf returns the next hop and interface for the given prefix.
-// If the next hop or interface is pointing to the VPN interface, it will return an error
-func addRouteToNonVPNIntf(
-	prefix netip.Prefix,
-	vpnIntf *iface.WGIface,
-	initialNextHop netip.Addr,
-	initialIntf *net.Interface,
-) (netip.Addr, string, error) {
-	addr := prefix.Addr()
-	switch {
-	case addr.IsLoopback():
-		return netip.Addr{}, "", fmt.Errorf("adding route for loopback address %s is not allowed", prefix)
-	case addr.IsLinkLocalUnicast():
-		return netip.Addr{}, "", fmt.Errorf("adding route for link-local unicast address %s is not allowed", prefix)
-	case addr.IsLinkLocalMulticast():
-		return netip.Addr{}, "", fmt.Errorf("adding route for link-local multicast address %s is not allowed", prefix)
-	case addr.IsInterfaceLocalMulticast():
-		return netip.Addr{}, "", fmt.Errorf("adding route for interface-local multicast address %s is not allowed", prefix)
-	case addr.IsUnspecified():
-		return netip.Addr{}, "", fmt.Errorf("adding route for unspecified address %s is not allowed", prefix)
-	case addr.IsMulticast():
-		return netip.Addr{}, "", fmt.Errorf("adding route for multicast address %s is not allowed", prefix)
-	}
-
-	// Determine the exit interface and next hop for the prefix, so we can add a specific route
-	nexthop, intf, err := getNextHop(addr)
-	if err != nil {
-		return netip.Addr{}, "", fmt.Errorf("get next hop: %s", err)
-	}
-
-	log.Debugf("Found next hop %s for prefix %s with interface %v", nexthop, prefix, intf)
-	exitNextHop := nexthop
-	var exitIntf string
-	if intf != nil {
-		exitIntf = intf.Name
-	}
-
-	vpnAddr, ok := netip.AddrFromSlice(vpnIntf.Address().IP)
-	if !ok {
-		return netip.Addr{}, "", fmt.Errorf("failed to convert vpn address to netip.Addr")
-	}
-
-	// if next hop is the VPN address or the interface is the VPN interface, we should use the initial values
-	if exitNextHop == vpnAddr || exitIntf == vpnIntf.Name() {
-		log.Debugf("Route for prefix %s is pointing to the VPN interface", prefix)
-		exitNextHop = initialNextHop
-		if initialIntf != nil {
-			exitIntf = initialIntf.Name
-		}
-	}
-
-	log.Debugf("Adding a new route for prefix %s with next hop %s", prefix, exitNextHop)
-	if err := addToRouteTable(prefix, exitNextHop, exitIntf); err != nil {
-		return netip.Addr{}, "", fmt.Errorf("add route to table: %w", err)
-	}
-
-	return exitNextHop, exitIntf, nil
-}
-
-// addVPNRoute adds a new route to the vpn interface, it splits the default prefix
-// in two /1 prefixes to avoid replacing the existing default route
 func addVPNRoute(prefix netip.Prefix, intf string) error {
-	if prefix == defaultv4 {
+	return genericAddVPNRoute(prefix, intf)
-		if err := addToRouteTable(splitDefaultv4_1, netip.Addr{}, intf); err != nil {
-			return err
-		}
-		if err := addToRouteTable(splitDefaultv4_2, netip.Addr{}, intf); err != nil {
-			if err2 := removeFromRouteTable(splitDefaultv4_1, netip.Addr{}, intf); err2 != nil {
-				log.Warnf("Failed to rollback route addition: %s", err2)
-			}
-			return err
 }
 
-		// TODO: remove once IPv6 is supported on the interface
-		if err := addToRouteTable(splitDefaultv6_1, netip.Addr{}, intf); err != nil {
-			return fmt.Errorf("add unreachable route split 1: %w", err)
-		}
-		if err := addToRouteTable(splitDefaultv6_2, netip.Addr{}, intf); err != nil {
-			if err2 := removeFromRouteTable(splitDefaultv6_1, netip.Addr{}, intf); err2 != nil {
-				log.Warnf("Failed to rollback route addition: %s", err2)
-			}
-			return fmt.Errorf("add unreachable route split 2: %w", err)
-		}
-
-		return nil
-	} else if prefix == defaultv6 {
-		if err := addToRouteTable(splitDefaultv6_1, netip.Addr{}, intf); err != nil {
-			return fmt.Errorf("add unreachable route split 1: %w", err)
-		}
-		if err := addToRouteTable(splitDefaultv6_2, netip.Addr{}, intf); err != nil {
-			if err2 := removeFromRouteTable(splitDefaultv6_1, netip.Addr{}, intf); err2 != nil {
-				log.Warnf("Failed to rollback route addition: %s", err2)
-			}
-			return fmt.Errorf("add unreachable route split 2: %w", err)
-		}
-
-		return nil
-	}
-
-	return addNonExistingRoute(prefix, intf)
-}
-
-// addNonExistingRoute adds a new route to the vpn interface if it doesn't exist in the current routing table
-func addNonExistingRoute(prefix netip.Prefix, intf string) error {
-	ok, err := existsInRouteTable(prefix)
-	if err != nil {
-		return fmt.Errorf("exists in route table: %w", err)
-	}
-	if ok {
-		log.Warnf("Skipping adding a new route for network %s because it already exists", prefix)
-		return nil
-	}
-
-	ok, err = isSubRange(prefix)
-	if err != nil {
-		return fmt.Errorf("sub range: %w", err)
-	}
-
-	if ok {
-		err := addRouteForCurrentDefaultGateway(prefix)
-		if err != nil {
-			log.Warnf("Unable to add route for current default gateway route. Will proceed without it. error: %s", err)
-		}
-	}
-
-	return addToRouteTable(prefix, netip.Addr{}, intf)
-}
-
-// removeVPNRoute removes the route from the vpn interface. If a default prefix is given,
-// it will remove the split /1 prefixes
 func removeVPNRoute(prefix netip.Prefix, intf string) error {
-	if prefix == defaultv4 {
+	return genericRemoveVPNRoute(prefix, intf)
-		var result *multierror.Error
-		if err := removeFromRouteTable(splitDefaultv4_1, netip.Addr{}, intf); err != nil {
-			result = multierror.Append(result, err)
-		}
-		if err := removeFromRouteTable(splitDefaultv4_2, netip.Addr{}, intf); err != nil {
-			result = multierror.Append(result, err)
-		}
-
-		// TODO: remove once IPv6 is supported on the interface
-		if err := removeFromRouteTable(splitDefaultv6_1, netip.Addr{}, intf); err != nil {
-			result = multierror.Append(result, err)
-		}
-		if err := removeFromRouteTable(splitDefaultv6_2, netip.Addr{}, intf); err != nil {
-			result = multierror.Append(result, err)
-		}
-
-		return result.ErrorOrNil()
-	} else if prefix == defaultv6 {
-		var result *multierror.Error
-		if err := removeFromRouteTable(splitDefaultv6_1, netip.Addr{}, intf); err != nil {
-			result = multierror.Append(result, err)
-		}
-		if err := removeFromRouteTable(splitDefaultv6_2, netip.Addr{}, intf); err != nil {
-			result = multierror.Append(result, err)
-		}
-
-		return result.ErrorOrNil()
-	}
-
-	return removeFromRouteTable(prefix, netip.Addr{}, intf)
-}
-
-func getPrefixFromIP(ip net.IP) (*netip.Prefix, error) {
-	addr, ok := netip.AddrFromSlice(ip)
-	if !ok {
-		return nil, fmt.Errorf("parse IP address: %s", ip)
-	}
-	addr = addr.Unmap()
-
-	var prefixLength int
-	switch {
-	case addr.Is4():
-		prefixLength = 32
-	case addr.Is6():
-		prefixLength = 128
-	default:
-		return nil, fmt.Errorf("invalid IP address: %s", addr)
-	}
-
-	prefix := netip.PrefixFrom(addr, prefixLength)
-	return &prefix, nil
-}
-
-func setupRoutingWithRouteManager(routeManager **RouteManager, initAddresses []net.IP, wgIface *iface.WGIface) (peer.BeforeAddPeerHookFunc, peer.AfterRemovePeerHookFunc, error) {
-	initialNextHopV4, initialIntfV4, err := getNextHop(netip.IPv4Unspecified())
-	if err != nil {
-		log.Errorf("Unable to get initial v4 default next hop: %v", err)
-	}
-	initialNextHopV6, initialIntfV6, err := getNextHop(netip.IPv6Unspecified())
-	if err != nil {
-		log.Errorf("Unable to get initial v6 default next hop: %v", err)
-	}
-
-	*routeManager = NewRouteManager(
-		func(prefix netip.Prefix) (netip.Addr, string, error) {
-			addr := prefix.Addr()
-			nexthop, intf := initialNextHopV4, initialIntfV4
-			if addr.Is6() {
-				nexthop, intf = initialNextHopV6, initialIntfV6
-			}
-			return addRouteToNonVPNIntf(prefix, wgIface, nexthop, intf)
-		},
-		removeFromRouteTable,
-	)
-
-	return setupHooks(*routeManager, initAddresses)
-}
-
-func cleanupRoutingWithRouteManager(routeManager *RouteManager) error {
-	if routeManager == nil {
-		return nil
-	}
-
-	// TODO: Remove hooks selectively
-	nbnet.RemoveDialerHooks()
-	nbnet.RemoveListenerHooks()
-
-	if err := routeManager.Flush(); err != nil {
-		return fmt.Errorf("flush route manager: %w", err)
-	}
-
-	return nil
-}
-
-func setupHooks(routeManager *RouteManager, initAddresses []net.IP) (peer.BeforeAddPeerHookFunc, peer.AfterRemovePeerHookFunc, error) {
-	beforeHook := func(connID nbnet.ConnectionID, ip net.IP) error {
-		prefix, err := getPrefixFromIP(ip)
-		if err != nil {
-			return fmt.Errorf("convert ip to prefix: %w", err)
-		}
-
-		if err := routeManager.AddRouteRef(connID, *prefix); err != nil {
-			return fmt.Errorf("adding route reference: %v", err)
-		}
-
-		return nil
-	}
-	afterHook := func(connID nbnet.ConnectionID) error {
-		if err := routeManager.RemoveRouteRef(connID); err != nil {
-			return fmt.Errorf("remove route reference: %w", err)
-		}
-
-		return nil
-	}
-
-	for _, ip := range initAddresses {
-		if err := beforeHook("init", ip); err != nil {
-			log.Errorf("Failed to add route reference: %v", err)
-		}
-	}
-
-	nbnet.AddDialerHook(func(ctx context.Context, connID nbnet.ConnectionID, resolvedIPs []net.IPAddr) error {
-		if ctx.Err() != nil {
-			return ctx.Err()
-		}
-
-		var result *multierror.Error
-		for _, ip := range resolvedIPs {
-			result = multierror.Append(result, beforeHook(connID, ip.IP))
-		}
-		return result.ErrorOrNil()
-	})
-
-	nbnet.AddDialerCloseHook(func(connID nbnet.ConnectionID, conn *net.Conn) error {
-		return afterHook(connID)
-	})
-
-	nbnet.AddListenerWriteHook(func(connID nbnet.ConnectionID, ip *net.IPAddr, data []byte) error {
-		return beforeHook(connID, ip.IP)
-	})
-
-	nbnet.AddListenerCloseHook(func(connID nbnet.ConnectionID, conn net.PacketConn) error {
-		return afterHook(connID)
-	})
-
-	return beforeHook, afterHook, nil
 }

client/internal/routemanager/systemops_test.go

@@ -1,13 +1,15 @@
-//go:build !linux && !ios
+//go:build !android && !ios
 
 package routemanager
 
 import (
 	"bytes"
+	"context"
 	"fmt"
 	"net"
 	"net/netip"
 	"os"
+	"runtime"
 	"strings"
 	"testing"
 
@@ -20,16 +22,9 @@ import (
 	"github.com/netbirdio/netbird/iface"
 )
 
-func assertWGOutInterface(t *testing.T, prefix netip.Prefix, wgIface *iface.WGIface, invert bool) {
+type dialer interface {
-	t.Helper()
+	Dial(network, address string) (net.Conn, error)
-
+	DialContext(ctx context.Context, network, address string) (net.Conn, error)
-	prefixGateway, _, err := getNextHop(prefix.Addr())
-	require.NoError(t, err, "getNextHop should not return err")
-	if invert {
-		assert.NotEqual(t, wgIface.Address().IP.String(), prefixGateway.String(), "route should not point to wireguard interface IP")
-	} else {
-		assert.Equal(t, wgIface.Address().IP.String(), prefixGateway.String(), "route should point to wireguard interface IP")
-	}
 }
 
 func TestAddRemoveRoutes(t *testing.T) {
@@ -72,8 +67,8 @@ func TestAddRemoveRoutes(t *testing.T) {
 				assert.NoError(t, cleanupRouting())
 			})
 
-			err = addVPNRoute(testCase.prefix, wgInterface.Name())
+			err = genericAddVPNRoute(testCase.prefix, wgInterface.Name())
-			require.NoError(t, err, "addVPNRoute should not return err")
+			require.NoError(t, err, "genericAddVPNRoute should not return err")
 
 			if testCase.shouldRouteToWireguard {
 				assertWGOutInterface(t, testCase.prefix, wgInterface, false)
@@ -83,8 +78,8 @@ func TestAddRemoveRoutes(t *testing.T) {
 			exists, err := existsInRouteTable(testCase.prefix)
 			require.NoError(t, err, "existsInRouteTable should not return err")
 			if exists && testCase.shouldRouteToWireguard {
-				err = removeVPNRoute(testCase.prefix, wgInterface.Name())
+				err = genericRemoveVPNRoute(testCase.prefix, wgInterface.Name())
-				require.NoError(t, err, "removeVPNRoute should not return err")
+				require.NoError(t, err, "genericRemoveVPNRoute should not return err")
 
 				prefixGateway, _, err := getNextHop(testCase.prefix.Addr())
 				require.NoError(t, err, "getNextHop should not return err")
@@ -144,7 +139,7 @@ func TestGetNextHop(t *testing.T) {
 	}
 }
 
-func TestAddExistAndRemoveRouteNonAndroid(t *testing.T) {
+func TestAddExistAndRemoveRoute(t *testing.T) {
 	defaultGateway, _, err := getNextHop(netip.MustParseAddr("0.0.0.0"))
 	t.Log("defaultGateway: ", defaultGateway)
 	if err != nil {
@@ -205,20 +200,14 @@ func TestAddExistAndRemoveRouteNonAndroid(t *testing.T) {
 			err = wgInterface.Create()
 			require.NoError(t, err, "should create testing wireguard interface")
 
-			_, _, err = setupRouting(nil, nil)
-			require.NoError(t, err)
-			t.Cleanup(func() {
-				assert.NoError(t, cleanupRouting())
-			})
-
 			// Prepare the environment
 			if testCase.preExistingPrefix.IsValid() {
-				err := addVPNRoute(testCase.preExistingPrefix, wgInterface.Name())
+				err := genericAddVPNRoute(testCase.preExistingPrefix, wgInterface.Name())
 				require.NoError(t, err, "should not return err when adding pre-existing route")
 			}
 
 			// Add the route
-			err = addVPNRoute(testCase.prefix, wgInterface.Name())
+			err = genericAddVPNRoute(testCase.prefix, wgInterface.Name())
 			require.NoError(t, err, "should not return err when adding route")
 
 			if testCase.shouldAddRoute {
@@ -228,7 +217,7 @@ func TestAddExistAndRemoveRouteNonAndroid(t *testing.T) {
 				require.True(t, ok, "route should exist")
 
 				// remove route again if added
-				err = removeVPNRoute(testCase.prefix, wgInterface.Name())
+				err = genericRemoveVPNRoute(testCase.prefix, wgInterface.Name())
 				require.NoError(t, err, "should not return err")
 			}
 
@@ -284,12 +273,6 @@ func TestIsSubRange(t *testing.T) {
 }
 
 func TestExistsInRouteTable(t *testing.T) {
-	_, _, err := setupRouting(nil, nil)
-	require.NoError(t, err)
-	t.Cleanup(func() {
-		assert.NoError(t, cleanupRouting())
-	})
-
 	addresses, err := net.InterfaceAddrs()
 	if err != nil {
 		t.Fatal("shouldn't return error when fetching interface addresses: ", err)
@@ -298,10 +281,19 @@ func TestExistsInRouteTable(t *testing.T) {
 	var addressPrefixes []netip.Prefix
 	for _, address := range addresses {
 		p := netip.MustParsePrefix(address.String())
-		// Windows sometimes has hidden interface link local addrs that don't turn up on any interface
+		if p.Addr().Is6() {
-		if p.Addr().Is4() && !p.Addr().IsLinkLocalUnicast() {
+			continue
-			addressPrefixes = append(addressPrefixes, p.Masked())
 		}
+		// Windows sometimes has hidden interface link local addrs that don't turn up on any interface
+		if runtime.GOOS == "windows" && p.Addr().IsLinkLocalUnicast() {
+			continue
+		}
+		// Linux loopback 127/8 is in the local table, not in the main table and always takes precedence
+		if runtime.GOOS == "linux" && p.Addr().IsLoopback() {
+			continue
+		}
+
+		addressPrefixes = append(addressPrefixes, p.Masked())
 	}
 
 	for _, prefix := range addressPrefixes {
@@ -314,3 +306,97 @@ func TestExistsInRouteTable(t *testing.T) {
 		}
 	}
 }
+
+func createWGInterface(t *testing.T, interfaceName, ipAddressCIDR string, listenPort int) *iface.WGIface {
+	t.Helper()
+
+	peerPrivateKey, err := wgtypes.GeneratePrivateKey()
+	require.NoError(t, err)
+
+	newNet, err := stdnet.NewNet()
+	require.NoError(t, err)
+
+	wgInterface, err := iface.NewWGIFace(interfaceName, ipAddressCIDR, listenPort, peerPrivateKey.String(), iface.DefaultMTU, newNet, nil)
+	require.NoError(t, err, "should create testing WireGuard interface")
+
+	err = wgInterface.Create()
+	require.NoError(t, err, "should create testing WireGuard interface")
+
+	t.Cleanup(func() {
+		wgInterface.Close()
+	})
+
+	return wgInterface
+}
+
+func setupTestEnv(t *testing.T) {
+	t.Helper()
+
+	setupDummyInterfacesAndRoutes(t)
+
+	wgIface := createWGInterface(t, expectedVPNint, "100.64.0.1/24", 51820)
+	t.Cleanup(func() {
+		assert.NoError(t, wgIface.Close())
+	})
+
+	_, _, err := setupRouting(nil, wgIface)
+	require.NoError(t, err, "setupRouting should not return err")
+	t.Cleanup(func() {
+		assert.NoError(t, cleanupRouting())
+	})
+
+	// default route exists in main table and vpn table
+	err = addVPNRoute(netip.MustParsePrefix("0.0.0.0/0"), wgIface.Name())
+	require.NoError(t, err, "addVPNRoute should not return err")
+	t.Cleanup(func() {
+		err = removeVPNRoute(netip.MustParsePrefix("0.0.0.0/0"), wgIface.Name())
+		assert.NoError(t, err, "removeVPNRoute should not return err")
+	})
+
+	// 10.0.0.0/8 route exists in main table and vpn table
+	err = addVPNRoute(netip.MustParsePrefix("10.0.0.0/8"), wgIface.Name())
+	require.NoError(t, err, "addVPNRoute should not return err")
+	t.Cleanup(func() {
+		err = removeVPNRoute(netip.MustParsePrefix("10.0.0.0/8"), wgIface.Name())
+		assert.NoError(t, err, "removeVPNRoute should not return err")
+	})
+
+	// 10.10.0.0/24 more specific route exists in vpn table
+	err = addVPNRoute(netip.MustParsePrefix("10.10.0.0/24"), wgIface.Name())
+	require.NoError(t, err, "addVPNRoute should not return err")
+	t.Cleanup(func() {
+		err = removeVPNRoute(netip.MustParsePrefix("10.10.0.0/24"), wgIface.Name())
+		assert.NoError(t, err, "removeVPNRoute should not return err")
+	})
+
+	// 127.0.10.0/24 more specific route exists in vpn table
+	err = addVPNRoute(netip.MustParsePrefix("127.0.10.0/24"), wgIface.Name())
+	require.NoError(t, err, "addVPNRoute should not return err")
+	t.Cleanup(func() {
+		err = removeVPNRoute(netip.MustParsePrefix("127.0.10.0/24"), wgIface.Name())
+		assert.NoError(t, err, "removeVPNRoute should not return err")
+	})
+
+	// unique route in vpn table
+	err = addVPNRoute(netip.MustParsePrefix("172.16.0.0/12"), wgIface.Name())
+	require.NoError(t, err, "addVPNRoute should not return err")
+	t.Cleanup(func() {
+		err = removeVPNRoute(netip.MustParsePrefix("172.16.0.0/12"), wgIface.Name())
+		assert.NoError(t, err, "removeVPNRoute should not return err")
+	})
+}
+
+func assertWGOutInterface(t *testing.T, prefix netip.Prefix, wgIface *iface.WGIface, invert bool) {
+	t.Helper()
+	if runtime.GOOS == "linux" && prefix.Addr().IsLoopback() {
+		return
+	}
+
+	prefixGateway, _, err := getNextHop(prefix.Addr())
+	require.NoError(t, err, "getNextHop should not return err")
+	if invert {
+		assert.NotEqual(t, wgIface.Address().IP.String(), prefixGateway.String(), "route should not point to wireguard interface IP")
+	} else {
+		assert.Equal(t, wgIface.Address().IP.String(), prefixGateway.String(), "route should point to wireguard interface IP")
+	}
+}

client/internal/routemanager/sytemops_test.go

@@ -1,101 +0,0 @@
-//go:build !android && !ios
-
-package routemanager
-
-import (
-	"context"
-	"net"
-	"net/netip"
-	"testing"
-
-	"github.com/stretchr/testify/assert"
-	"github.com/stretchr/testify/require"
-	"golang.zx2c4.com/wireguard/wgctrl/wgtypes"
-
-	"github.com/netbirdio/netbird/client/internal/stdnet"
-	"github.com/netbirdio/netbird/iface"
-)
-
-type dialer interface {
-	Dial(network, address string) (net.Conn, error)
-	DialContext(ctx context.Context, network, address string) (net.Conn, error)
-}
-
-func createWGInterface(t *testing.T, interfaceName, ipAddressCIDR string, listenPort int) *iface.WGIface {
-	t.Helper()
-
-	peerPrivateKey, err := wgtypes.GeneratePrivateKey()
-	require.NoError(t, err)
-
-	newNet, err := stdnet.NewNet(nil)
-	require.NoError(t, err)
-
-	wgInterface, err := iface.NewWGIFace(interfaceName, ipAddressCIDR, listenPort, peerPrivateKey.String(), iface.DefaultMTU, newNet, nil)
-	require.NoError(t, err, "should create testing WireGuard interface")
-
-	err = wgInterface.Create()
-	require.NoError(t, err, "should create testing WireGuard interface")
-
-	t.Cleanup(func() {
-		wgInterface.Close()
-	})
-
-	return wgInterface
-}
-
-func setupTestEnv(t *testing.T) {
-	t.Helper()
-
-	setupDummyInterfacesAndRoutes(t)
-
-	wgIface := createWGInterface(t, expectedVPNint, "100.64.0.1/24", 51820)
-	t.Cleanup(func() {
-		assert.NoError(t, wgIface.Close())
-	})
-
-	_, _, err := setupRouting(nil, wgIface)
-	require.NoError(t, err, "setupRouting should not return err")
-	t.Cleanup(func() {
-		assert.NoError(t, cleanupRouting())
-	})
-
-	// default route exists in main table and vpn table
-	err = addVPNRoute(netip.MustParsePrefix("0.0.0.0/0"), wgIface.Name())
-	require.NoError(t, err, "addVPNRoute should not return err")
-	t.Cleanup(func() {
-		err = removeVPNRoute(netip.MustParsePrefix("0.0.0.0/0"), wgIface.Name())
-		assert.NoError(t, err, "removeVPNRoute should not return err")
-	})
-
-	// 10.0.0.0/8 route exists in main table and vpn table
-	err = addVPNRoute(netip.MustParsePrefix("10.0.0.0/8"), wgIface.Name())
-	require.NoError(t, err, "addVPNRoute should not return err")
-	t.Cleanup(func() {
-		err = removeVPNRoute(netip.MustParsePrefix("10.0.0.0/8"), wgIface.Name())
-		assert.NoError(t, err, "removeVPNRoute should not return err")
-	})
-
-	// 10.10.0.0/24 more specific route exists in vpn table
-	err = addVPNRoute(netip.MustParsePrefix("10.10.0.0/24"), wgIface.Name())
-	require.NoError(t, err, "addVPNRoute should not return err")
-	t.Cleanup(func() {
-		err = removeVPNRoute(netip.MustParsePrefix("10.10.0.0/24"), wgIface.Name())
-		assert.NoError(t, err, "removeVPNRoute should not return err")
-	})
-
-	// 127.0.10.0/24 more specific route exists in vpn table
-	err = addVPNRoute(netip.MustParsePrefix("127.0.10.0/24"), wgIface.Name())
-	require.NoError(t, err, "addVPNRoute should not return err")
-	t.Cleanup(func() {
-		err = removeVPNRoute(netip.MustParsePrefix("127.0.10.0/24"), wgIface.Name())
-		assert.NoError(t, err, "removeVPNRoute should not return err")
-	})
-
-	// unique route in vpn table
-	err = addVPNRoute(netip.MustParsePrefix("172.16.0.0/12"), wgIface.Name())
-	require.NoError(t, err, "addVPNRoute should not return err")
-	t.Cleanup(func() {
-		err = removeVPNRoute(netip.MustParsePrefix("172.16.0.0/12"), wgIface.Name())
-		assert.NoError(t, err, "removeVPNRoute should not return err")
-	})
-}

util/net/dialer.go

@@ -35,7 +35,7 @@ func DialUDP(network string, laddr, raddr *net.UDPAddr) (*net.UDPConn, error) {
 	udpConn, ok := conn.(*net.UDPConn)
 	if !ok {
 		if err := conn.Close(); err != nil {
-			log.Errorf("Failed to closeConn connection: %v", err)
+			log.Errorf("Failed to close connection: %v", err)
 		}
 		return nil, fmt.Errorf("expected UDP connection, got different type")
 	}

util/net/listener_generic.go

@@ -145,10 +145,19 @@ func closeConn(id ConnectionID, conn net.PacketConn) error {
 // ListenUDP listens on the network address and returns a transport.UDPConn
 // which includes support for write and close hooks.
 func ListenUDP(network string, laddr *net.UDPAddr) (*UDPConn, error) {
-	udpConn, err := net.ListenUDP(network, laddr)
+	conn, err := NewListener().ListenPacket(context.Background(), network, laddr.String())
 	if err != nil {
 		return nil, fmt.Errorf("listen UDP: %w", err)
 	}
-	connID := GenerateConnID()
+
-	return &UDPConn{UDPConn: udpConn, ID: connID, seenAddrs: &sync.Map{}}, nil
+	packetConn := conn.(*PacketConn)
+	udpConn, ok := packetConn.PacketConn.(*net.UDPConn)
+	if !ok {
+		if err := packetConn.Close(); err != nil {
+			log.Errorf("Failed to close connection: %v", err)
+		}
+		return nil, fmt.Errorf("expected UDPConn, got different type")
+	}
+
+	return &UDPConn{UDPConn: udpConn, ID: packetConn.ID, seenAddrs: &sync.Map{}}, nil
 }