[client] Unify route selection in the route manager

Move route select/deselect handling from the daemon server into exported
routemanager methods (SelectRoutes, DeselectRoutes, SelectAllRoutes,
DeselectAllRoutes) so every consumer shares one implementation: v4/v6
exit-pair expansion, exit-node mutual exclusion, and selection triggering.

Previously the exit-node exclusivity lived only in the daemon's
SelectNetworks RPC, so the Android and iOS bindings could leave two exit
nodes selected until the next network map reconciliation. Both bindings
now call the shared manager methods and enforce exclusivity at toggle
time, matching the desktop behavior.

client/internal/routemanager/manager.go

@@ -52,6 +52,10 @@ type Manager interface {
 	UpdateRoutes(updateSerial uint64, serverRoutes map[route.ID]*route.Route, clientRoutes route.HAMap, useNewDNSRoute bool) error
 	ClassifyRoutes(newRoutes []*route.Route) (map[route.ID]*route.Route, route.HAMap)
 	TriggerSelection(route.HAMap)
+	SelectRoutes(ids []route.NetID, appendRoute bool) error
+	DeselectRoutes(ids []route.NetID) error
+	SelectAllRoutes()
+	DeselectAllRoutes()
 	GetRouteSelector() *routeselector.RouteSelector
 	GetClientRoutes() route.HAMap
 	GetSelectedClientRoutes() route.HAMap
@@ -800,7 +804,7 @@ func (m *DefaultManager) collectExitNodeInfo(clientRoutes route.HAMap) exitNodeI
 	var info exitNodeInfo
 
 	for haID, routes := range clientRoutes {
-		if !m.isExitNodeRoute(routes) {
+		if !isExitNodeRoutes(routes) {
 			continue
 		}
 
@@ -820,13 +824,6 @@ func (m *DefaultManager) collectExitNodeInfo(clientRoutes route.HAMap) exitNodeI
 	return info
 }
 
-func (m *DefaultManager) isExitNodeRoute(routes []*route.Route) bool {
-	if len(routes) == 0 {
-		return false
-	}
-	return route.IsV4DefaultRoute(routes[0].Network) || route.IsV6DefaultRoute(routes[0].Network)
-}
-
 func (m *DefaultManager) categorizeUserSelection(netID route.NetID, info *exitNodeInfo) {
 	if m.routeSelector.IsSelected(netID) {
 		info.userSelected = append(info.userSelected, netID)

client/internal/routemanager/mock.go

@@ -16,6 +16,8 @@ type MockManager struct {
 	ClassifyRoutesFunc           func(routes []*route.Route) (map[route.ID]*route.Route, route.HAMap)
 	UpdateRoutesFunc             func(updateSerial uint64, serverRoutes map[route.ID]*route.Route, clientRoutes route.HAMap, useNewDNSRoute bool) error
 	TriggerSelectionFunc         func(haMap route.HAMap)
+	SelectRoutesFunc             func(ids []route.NetID, appendRoute bool) error
+	DeselectRoutesFunc           func(ids []route.NetID) error
 	GetRouteSelectorFunc         func() *routeselector.RouteSelector
 	GetClientRoutesFunc          func() route.HAMap
 	GetSelectedClientRoutesFunc  func() route.HAMap
@@ -55,6 +57,30 @@ func (m *MockManager) TriggerSelection(networks route.HAMap) {
 	}
 }
 
+// SelectRoutes mock implementation of SelectRoutes from Manager interface
+func (m *MockManager) SelectRoutes(ids []route.NetID, appendRoute bool) error {
+	if m.SelectRoutesFunc != nil {
+		return m.SelectRoutesFunc(ids, appendRoute)
+	}
+	return nil
+}
+
+// DeselectRoutes mock implementation of DeselectRoutes from Manager interface
+func (m *MockManager) DeselectRoutes(ids []route.NetID) error {
+	if m.DeselectRoutesFunc != nil {
+		return m.DeselectRoutesFunc(ids)
+	}
+	return nil
+}
+
+// SelectAllRoutes mock implementation of SelectAllRoutes from Manager interface
+func (m *MockManager) SelectAllRoutes() {
+}
+
+// DeselectAllRoutes mock implementation of DeselectAllRoutes from Manager interface
+func (m *MockManager) DeselectAllRoutes() {
+}
+
 // GetRouteSelector mock implementation of GetRouteSelector from Manager interface
 func (m *MockManager) GetRouteSelector() *routeselector.RouteSelector {
 	if m.GetRouteSelectorFunc != nil {

client/internal/routemanager/selection.go

@@ -0,0 +1,120 @@
+package routemanager
+
+import (
+	"fmt"
+	"slices"
+
+	log "github.com/sirupsen/logrus"
+	"golang.org/x/exp/maps"
+
+	"github.com/netbirdio/netbird/route"
+)
+
+// SelectRoutes selects the routes with the given network IDs and applies the
+// new selection. V4/v6 exit-node pairs are expanded automatically. Exit nodes
+// are mutually exclusive: if the selection activates an exit node, every other
+// available exit node is deselected so two can't be active at once. With
+// appendRoute=false the previous selection is replaced instead of extended.
+func (m *DefaultManager) SelectRoutes(ids []route.NetID, appendRoute bool) error {
+	if err := m.selectRoutes(ids, appendRoute); err != nil {
+		return err
+	}
+	m.TriggerSelection(m.GetClientRoutes())
+	return nil
+}
+
+// DeselectRoutes removes the routes with the given network IDs from the
+// selection and applies the change. V4/v6 exit-node pairs are expanded
+// automatically.
+func (m *DefaultManager) DeselectRoutes(ids []route.NetID) error {
+	if err := m.deselectRoutes(ids); err != nil {
+		return err
+	}
+	m.TriggerSelection(m.GetClientRoutes())
+	return nil
+}
+
+func (m *DefaultManager) deselectRoutes(ids []route.NetID) error {
+	routesMap := m.GetClientRoutesWithNetID()
+	routes := route.ExpandV6ExitPairs(slices.Clone(ids), routesMap)
+
+	log.Debugf("deselecting routes with ids: %v", routes)
+
+	if err := m.routeSelector.DeselectRoutes(routes, maps.Keys(routesMap)); err != nil {
+		return fmt.Errorf("deselect routes: %w", err)
+	}
+
+	return nil
+}
+
+// SelectAllRoutes selects every available route and applies the selection.
+func (m *DefaultManager) SelectAllRoutes() {
+	m.routeSelector.SelectAllRoutes()
+	m.TriggerSelection(m.GetClientRoutes())
+}
+
+// DeselectAllRoutes deselects every route and applies the change.
+func (m *DefaultManager) DeselectAllRoutes() {
+	m.routeSelector.DeselectAllRoutes()
+	m.TriggerSelection(m.GetClientRoutes())
+}
+
+func (m *DefaultManager) selectRoutes(ids []route.NetID, appendRoute bool) error {
+	routesMap := m.GetClientRoutesWithNetID()
+	routes := route.ExpandV6ExitPairs(slices.Clone(ids), routesMap)
+	allIDs := maps.Keys(routesMap)
+
+	log.Debugf("selecting routes with ids: %v", routes)
+
+	if err := m.routeSelector.SelectRoutes(routes, appendRoute, allIDs); err != nil {
+		return fmt.Errorf("select routes: %w", err)
+	}
+
+	// Exit nodes are mutually exclusive: if this selection activates an
+	// exit node, deselect every other available exit node so two can't be
+	// selected at once. Non-exit route selections are left untouched.
+	if requestActivatesExitNode(routes, routesMap) {
+		if others := otherExitNodeIDs(routesMap, routes); len(others) > 0 {
+			if err := m.routeSelector.DeselectRoutes(others, allIDs); err != nil {
+				return fmt.Errorf("deselect sibling exit nodes: %w", err)
+			}
+		}
+	}
+
+	return nil
+}
+
+func isExitNodeRoutes(routes []*route.Route) bool {
+	return len(routes) > 0 && (route.IsV4DefaultRoute(routes[0].Network) || route.IsV6DefaultRoute(routes[0].Network))
+}
+
+// requestActivatesExitNode reports whether any requested NetID maps to an exit
+// node (default route) in the current route table.
+func requestActivatesExitNode(requested []route.NetID, routesMap map[route.NetID][]*route.Route) bool {
+	for _, id := range requested {
+		if isExitNodeRoutes(routesMap[id]) {
+			return true
+		}
+	}
+	return false
+}
+
+// otherExitNodeIDs returns every available exit-node NetID that is not in the
+// requested set — the siblings to deselect so a single exit node stays active.
+func otherExitNodeIDs(routesMap map[route.NetID][]*route.Route, requested []route.NetID) []route.NetID {
+	keep := make(map[route.NetID]struct{}, len(requested))
+	for _, id := range requested {
+		keep[id] = struct{}{}
+	}
+	var others []route.NetID
+	for id, routes := range routesMap {
+		if !isExitNodeRoutes(routes) {
+			continue
+		}
+		if _, ok := keep[id]; ok {
+			continue
+		}
+		others = append(others, id)
+	}
+	return others
+}

client/internal/routemanager/selection_test.go

@@ -0,0 +1,82 @@
+package routemanager
+
+import (
+	"net/netip"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"github.com/netbirdio/netbird/client/internal/routeselector"
+	"github.com/netbirdio/netbird/route"
+)
+
+func v6ExitRoute(netID, peer string) *route.Route {
+	return &route.Route{
+		NetID:   route.NetID(netID),
+		Network: netip.MustParsePrefix("::/0"),
+		Peer:    peer,
+	}
+}
+
+func newSelectionTestManager() *DefaultManager {
+	return &DefaultManager{
+		routeSelector: routeselector.NewRouteSelector(),
+		clientRoutes: route.HAMap{
+			"exitA|0.0.0.0/0":    {exitRoute("exitA", "p1", true)},
+			"exitA-v6|::/0":      {v6ExitRoute("exitA-v6", "p1")},
+			"exitB|0.0.0.0/0":    {exitRoute("exitB", "p2", true)},
+			"lan|192.168.1.0/24": {{NetID: "lan", Network: netip.MustParsePrefix("192.168.1.0/24"), Peer: "p3"}},
+		},
+	}
+}
+
+func TestSelectRoutes_ExitNodeExclusivity(t *testing.T) {
+	m := newSelectionTestManager()
+
+	// Selecting an exit node selects its v6 pair and deselects the sibling.
+	require.NoError(t, m.selectRoutes([]route.NetID{"exitA"}, true))
+	assert.True(t, m.routeSelector.IsSelected("exitA"), "exitA should be selected")
+	assert.True(t, m.routeSelector.IsSelected("exitA-v6"), "the v6 pair follows its v4 base")
+	assert.False(t, m.routeSelector.IsSelected("exitB"), "the sibling exit node must be deselected")
+
+	// Switching to the sibling deselects the previous exit node and its v6 pair.
+	require.NoError(t, m.selectRoutes([]route.NetID{"exitB"}, true))
+	assert.True(t, m.routeSelector.IsSelected("exitB"), "exitB should now be selected")
+	assert.False(t, m.routeSelector.IsSelected("exitA"), "the previous exit node must be deselected")
+	assert.False(t, m.routeSelector.IsSelected("exitA-v6"), "the previous exit node's v6 pair must be deselected")
+	assert.True(t, m.routeSelector.IsSelected("lan"), "non-exit route selection is untouched")
+
+	// Selecting a non-exit route leaves the active exit node alone.
+	require.NoError(t, m.selectRoutes([]route.NetID{"lan"}, true))
+	assert.True(t, m.routeSelector.IsSelected("exitB"), "selecting a non-exit route keeps the exit node")
+
+	// Deselecting the active exit node turns every exit node off.
+	require.NoError(t, m.deselectRoutes([]route.NetID{"exitB"}))
+	assert.False(t, m.routeSelector.IsSelected("exitB"), "exitB should be deselected")
+	assert.False(t, m.routeSelector.IsSelected("exitA"), "exitA stays deselected")
+	assert.True(t, m.routeSelector.IsSelected("lan"), "non-exit route selection is untouched")
+}
+
+func TestSelectRoutes_UnknownRoute(t *testing.T) {
+	m := newSelectionTestManager()
+
+	assert.Error(t, m.selectRoutes([]route.NetID{"missing"}, true), "selecting an unavailable route must fail")
+	assert.Error(t, m.deselectRoutes([]route.NetID{"missing"}), "deselecting an unavailable route must fail")
+}
+
+func TestExitNodeSelectionHelpers(t *testing.T) {
+	routesMap := map[route.NetID][]*route.Route{
+		"exitA": {{Network: netip.MustParsePrefix("0.0.0.0/0")}},
+		"exitB": {{Network: netip.MustParsePrefix("::/0")}},
+		"lan":   {{Network: netip.MustParsePrefix("192.168.0.0/16")}},
+	}
+
+	assert.True(t, requestActivatesExitNode([]route.NetID{"exitA"}, routesMap), "v4 default route is an exit node")
+	assert.True(t, requestActivatesExitNode([]route.NetID{"exitB"}, routesMap), "v6 default route is an exit node")
+	assert.False(t, requestActivatesExitNode([]route.NetID{"lan"}, routesMap), "lan route is not an exit node")
+	assert.False(t, requestActivatesExitNode([]route.NetID{"missing"}, routesMap), "unknown id is not an exit node")
+
+	others := otherExitNodeIDs(routesMap, []route.NetID{"exitB"})
+	assert.ElementsMatch(t, []route.NetID{"exitA"}, others, "only the other exit node is a sibling; the lan route is ignored")
+}