package integration

import (
	"cmp"
	"encoding/json"
	"fmt"
	"maps"
	"net/netip"
	"slices"
	"sort"
	"strconv"
	"strings"
	"testing"
	"time"

	cmpdiff "github.com/google/go-cmp/cmp"
	"github.com/google/go-cmp/cmp/cmpopts"
	v1 "github.com/juanfont/headscale/gen/go/headscale/v1"
	policyv2 "github.com/juanfont/headscale/hscontrol/policy/v2"
	"github.com/juanfont/headscale/hscontrol/routes"
	"github.com/juanfont/headscale/hscontrol/types"
	"github.com/juanfont/headscale/hscontrol/util"
	"github.com/juanfont/headscale/integration/dockertestutil"
	"github.com/juanfont/headscale/integration/hsic"
	"github.com/juanfont/headscale/integration/integrationutil"
	"github.com/juanfont/headscale/integration/tsic"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
	xmaps "golang.org/x/exp/maps"
	"tailscale.com/ipn/ipnstate"
	"tailscale.com/net/tsaddr"
	"tailscale.com/tailcfg"
	"tailscale.com/types/ipproto"
	"tailscale.com/types/views"
	"tailscale.com/util/must"
	"tailscale.com/util/slicesx"
	"tailscale.com/wgengine/filter"
)

var allPorts = filter.PortRange{First: 0, Last: 0xffff}

// This test is both testing the routes command and the propagation of
// routes.
func TestEnablingRoutes(t *testing.T) {
	IntegrationSkip(t)

	spec := ScenarioSpec{
		NodesPerUser: 3,
		Users:        []string{"user1"},
	}

	scenario, err := NewScenario(spec)

	require.NoErrorf(t, err, "failed to create scenario: %s", err)
	defer scenario.ShutdownAssertNoPanics(t)

	err = scenario.CreateHeadscaleEnv(
		[]tsic.Option{tsic.WithAcceptRoutes()},
		hsic.WithTestName("rt-enable"))
	requireNoErrHeadscaleEnv(t, err)

	allClients, err := scenario.ListTailscaleClients()
	requireNoErrListClients(t, err)

	err = scenario.WaitForTailscaleSync()
	requireNoErrSync(t, err)

	headscale, err := scenario.Headscale()
	requireNoErrGetHeadscale(t, err)

	expectedRoutes := map[string]string{
		"1": "10.0.0.0/24",
		"2": "10.0.1.0/24",
		"3": "10.0.2.0/24",
	}

	// advertise routes using the up command
	for _, client := range allClients {
		status := client.MustStatus()
		command := []string{
			"tailscale",
			"set",
			"--advertise-routes=" + expectedRoutes[string(status.Self.ID)],
		}
		_, _, err = client.Execute(command)
		require.NoErrorf(t, err, "failed to advertise route: %s", err)
	}

	err = scenario.WaitForTailscaleSync()
	requireNoErrSync(t, err)

	var nodes []*v1.Node
	// Wait for route advertisements to propagate to NodeStore
	assert.EventuallyWithT(t, func(ct *assert.CollectT) {
		var err error

		nodes, err = headscale.ListNodes()
		assert.NoError(ct, err)

		for _, node := range nodes {
			assert.Len(ct, node.GetAvailableRoutes(), 1)
			assert.Empty(ct, node.GetApprovedRoutes())
			assert.Empty(ct, node.GetSubnetRoutes())
		}
	}, integrationutil.ScaledTimeout(10*time.Second), 100*time.Millisecond, "route advertisements should propagate to all nodes")

	// Verify that no routes has been sent to the client,
	// they are not yet enabled.
	for _, client := range allClients {
		assert.EventuallyWithT(t, func(c *assert.CollectT) {
			status, err := client.Status()
			assert.NoError(c, err)

			for _, peerKey := range status.Peers() {
				peerStatus := status.Peer[peerKey]

				assert.Nil(c, peerStatus.PrimaryRoutes)
			}
		}, integrationutil.ScaledTimeout(5*time.Second), 200*time.Millisecond, "Verifying no routes are active before approval")
	}

	for _, node := range nodes {
		_, err := headscale.ApproveRoutes(
			node.GetId(),
			util.MustStringsToPrefixes(node.GetAvailableRoutes()),
		)
		require.NoError(t, err)
	}

	// Wait for route approvals to propagate to NodeStore
	assert.EventuallyWithT(t, func(ct *assert.CollectT) {
		var err error

		nodes, err = headscale.ListNodes()
		assert.NoError(ct, err)

		for _, node := range nodes {
			assert.Len(ct, node.GetAvailableRoutes(), 1)
			assert.Len(ct, node.GetApprovedRoutes(), 1)
			assert.Len(ct, node.GetSubnetRoutes(), 1)
		}
	}, integrationutil.ScaledTimeout(10*time.Second), 100*time.Millisecond, "route approvals should propagate to all nodes")

	// Wait for route state changes to propagate to clients
	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		// Verify that the clients can see the new routes
		for _, client := range allClients {
			status, err := client.Status()
			assert.NoError(c, err)

			for _, peerKey := range status.Peers() {
				peerStatus := status.Peer[peerKey]

				assert.NotNil(c, peerStatus.PrimaryRoutes)
				assert.NotNil(c, peerStatus.AllowedIPs)

				if peerStatus.AllowedIPs != nil {
					assert.Len(c, peerStatus.AllowedIPs.AsSlice(), 3)
				}

				requirePeerSubnetRoutesWithCollect(c, peerStatus, []netip.Prefix{netip.MustParsePrefix(expectedRoutes[string(peerStatus.ID)])})
			}
		}
	}, integrationutil.ScaledTimeout(10*time.Second), 500*time.Millisecond, "clients should see new routes")

	_, err = headscale.ApproveRoutes(
		1,
		[]netip.Prefix{netip.MustParsePrefix("10.0.1.0/24")},
	)
	require.NoError(t, err)

	_, err = headscale.ApproveRoutes(
		2,
		[]netip.Prefix{},
	)
	require.NoError(t, err)

	// Wait for route state changes to propagate to nodes
	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		var err error

		nodes, err = headscale.ListNodes()
		assert.NoError(c, err)

		for _, node := range nodes {
			if node.GetId() == 1 {
				assert.Len(c, node.GetAvailableRoutes(), 1) // 10.0.0.0/24
				assert.Len(c, node.GetApprovedRoutes(), 1)  // 10.0.1.0/24
				assert.Empty(c, node.GetSubnetRoutes())
			} else if node.GetId() == 2 {
				assert.Len(c, node.GetAvailableRoutes(), 1) // 10.0.1.0/24
				assert.Empty(c, node.GetApprovedRoutes())
				assert.Empty(c, node.GetSubnetRoutes())
			} else {
				assert.Len(c, node.GetAvailableRoutes(), 1) // 10.0.2.0/24
				assert.Len(c, node.GetApprovedRoutes(), 1)  // 10.0.2.0/24
				assert.Len(c, node.GetSubnetRoutes(), 1)    // 10.0.2.0/24
			}
		}
	}, integrationutil.ScaledTimeout(10*time.Second), 500*time.Millisecond, "route state changes should propagate to nodes")

	// Verify that the clients can see the new routes
	for _, client := range allClients {
		assert.EventuallyWithT(t, func(c *assert.CollectT) {
			status, err := client.Status()
			assert.NoError(c, err)

			for _, peerKey := range status.Peers() {
				peerStatus := status.Peer[peerKey]

				switch peerStatus.ID {
				case "1":
					requirePeerSubnetRoutesWithCollect(c, peerStatus, nil)
				case "2":
					requirePeerSubnetRoutesWithCollect(c, peerStatus, nil)
				default:
					requirePeerSubnetRoutesWithCollect(c, peerStatus, []netip.Prefix{netip.MustParsePrefix("10.0.2.0/24")})
				}
			}
		}, integrationutil.ScaledTimeout(5*time.Second), 200*time.Millisecond, "Verifying final route state visible to clients")
	}
}

//nolint:gocyclo // complex HA failover test scenario
func TestHASubnetRouterFailover(t *testing.T) {
	IntegrationSkip(t)

	propagationTime := integrationutil.ScaledTimeout(60 * time.Second)

	// Helper function to validate primary routes table state
	validatePrimaryRoutes := func(t *testing.T, headscale ControlServer, expectedRoutes *routes.DebugRoutes, message string) {
		t.Helper()
		assert.EventuallyWithT(t, func(c *assert.CollectT) {
			primaryRoutesState, err := headscale.PrimaryRoutes()
			assert.NoError(c, err)

			if diff := cmpdiff.Diff(expectedRoutes, primaryRoutesState, util.PrefixComparer); diff != "" {
				t.Log(message)
				t.Errorf("validatePrimaryRoutes mismatch (-want +got):\n%s", diff)
			}
		}, propagationTime, 200*time.Millisecond, "Validating primary routes table")
	}

	spec := ScenarioSpec{
		NodesPerUser: 3,
		Users:        []string{"user1", "user2"},
		Networks: map[string][]string{
			"usernet1": {"user1"},
			"usernet2": {"user2"},
		},
		ExtraService: map[string][]extraServiceFunc{
			"usernet1": {Webservice},
		},
		// We build the head image with curl and traceroute, so only use
		// that for this test.
		Versions: []string{"head"},
	}

	scenario, err := NewScenario(spec)
	require.NoErrorf(t, err, "failed to create scenario: %s", err)
	// defer scenario.ShutdownAssertNoPanics(t)

	err = scenario.CreateHeadscaleEnv(
		[]tsic.Option{tsic.WithAcceptRoutes()},
		hsic.WithTestName("rt-hafailover"),
	)
	requireNoErrHeadscaleEnv(t, err)

	allClients, err := scenario.ListTailscaleClients()
	requireNoErrListClients(t, err)

	err = scenario.WaitForTailscaleSync()
	requireNoErrSync(t, err)

	headscale, err := scenario.Headscale()
	requireNoErrGetHeadscale(t, err)

	prefp, err := scenario.SubnetOfNetwork("usernet1")
	require.NoError(t, err)

	pref := *prefp
	t.Logf("usernet1 prefix: %s", pref.String())

	usernet1, err := scenario.Network("usernet1")
	require.NoError(t, err)

	services, err := scenario.Services("usernet1")
	require.NoError(t, err)
	require.Len(t, services, 1)

	web := services[0]
	webip := netip.MustParseAddr(web.GetIPInNetwork(usernet1))
	weburl := fmt.Sprintf("http://%s/etc/hostname", webip)
	t.Logf("webservice: %s, %s", webip.String(), weburl)

	// Sort nodes by ID
	sort.SliceStable(allClients, func(i, j int) bool {
		statusI := allClients[i].MustStatus()
		statusJ := allClients[j].MustStatus()

		return statusI.Self.ID < statusJ.Self.ID
	})

	// This is ok because the scenario makes users in order, so the three first
	// nodes, which are subnet routes, will be created first, and the last user
	// will be created with the second.
	subRouter1 := allClients[0]
	subRouter2 := allClients[1]
	subRouter3 := allClients[2]

	client := allClients[3]

	t.Logf("%s (%s) picked as client", client.Hostname(), client.MustID())
	t.Logf("=== Initial Route Advertisement - Setting up HA configuration with 3 routers ===")
	t.Logf("[%s] Starting test section", time.Now().Format(TimestampFormat))
	t.Logf("  - Router 1 (%s): Advertising route %s - will become PRIMARY when approved", subRouter1.Hostname(), pref.String())
	t.Logf("  - Router 2 (%s): Advertising route %s - will be STANDBY when approved", subRouter2.Hostname(), pref.String())
	t.Logf("  - Router 3 (%s): Advertising route %s - will be STANDBY when approved", subRouter3.Hostname(), pref.String())
	t.Logf("  Expected: All 3 routers advertise the same route for redundancy, but only one will be primary at a time")

	for _, client := range allClients[:3] {
		command := []string{
			"tailscale",
			"set",
			"--advertise-routes=" + pref.String(),
		}
		_, _, err = client.Execute(command)
		require.NoErrorf(t, err, "failed to advertise route: %s", err)
	}

	err = scenario.WaitForTailscaleSync()
	requireNoErrSync(t, err)

	// Wait for route configuration changes after advertising routes
	var nodes []*v1.Node

	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		nodes, err = headscale.ListNodes()
		assert.NoError(c, err)
		assert.Len(c, nodes, 6)
		require.GreaterOrEqual(t, len(nodes), 3, "need at least 3 nodes to avoid panic")
		requireNodeRouteCountWithCollect(c, nodes[0], 1, 0, 0)
		requireNodeRouteCountWithCollect(c, nodes[1], 1, 0, 0)
		requireNodeRouteCountWithCollect(c, nodes[2], 1, 0, 0)
	}, propagationTime, 200*time.Millisecond, "Waiting for route advertisements: All 3 routers should have advertised routes (available=1) but none approved yet (approved=0, subnet=0)")

	// Verify that no routes has been sent to the client,
	// they are not yet enabled.
	for _, client := range allClients {
		assert.EventuallyWithT(t, func(c *assert.CollectT) {
			status, err := client.Status()
			assert.NoError(c, err)

			for _, peerKey := range status.Peers() {
				peerStatus := status.Peer[peerKey]

				assert.Nil(c, peerStatus.PrimaryRoutes)
				requirePeerSubnetRoutesWithCollect(c, peerStatus, nil)
			}
		}, propagationTime, 200*time.Millisecond, "Verifying no routes are active before approval")
	}

	// Declare variables that will be used across multiple EventuallyWithT blocks
	var (
		srs1, srs2, srs3 *ipnstate.Status
		clientStatus     *ipnstate.Status
		srs1PeerStatus   *ipnstate.PeerStatus
		srs2PeerStatus   *ipnstate.PeerStatus
		srs3PeerStatus   *ipnstate.PeerStatus
	)

	// Helper function to check test failure and print route map if needed
	checkFailureAndPrintRoutes := func(t *testing.T, client TailscaleClient) { //nolint:thelper
		if t.Failed() {
			t.Logf("[%s] Test failed at this checkpoint", time.Now().Format(TimestampFormat))

			status, err := client.Status()
			if err == nil {
				printCurrentRouteMap(t, xmaps.Values(status.Peer)...)
			}

			t.FailNow()
		}
	}

	// Validate primary routes table state - no routes approved yet
	validatePrimaryRoutes(t, headscale, &routes.DebugRoutes{
		AvailableRoutes: map[types.NodeID][]netip.Prefix{},
		PrimaryRoutes:   map[string]types.NodeID{}, // No primary routes yet
	}, "Primary routes table should be empty (no approved routes yet)")

	checkFailureAndPrintRoutes(t, client)

	// Enable route on node 1
	t.Logf("=== Approving route on router 1 (%s) - Single router mode (no HA yet) ===", subRouter1.Hostname())
	t.Logf("[%s] Starting test section", time.Now().Format(TimestampFormat))
	t.Logf("  Expected: Router 1 becomes PRIMARY with route %s active", pref.String())
	t.Logf("  Expected: Routers 2 & 3 remain with advertised but unapproved routes")
	t.Logf("  Expected: Client can access webservice through router 1 only")

	_, err = headscale.ApproveRoutes(
		MustFindNode(subRouter1.Hostname(), nodes).GetId(),
		[]netip.Prefix{pref},
	)
	require.NoError(t, err)

	// Wait for route approval on first subnet router
	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		nodes, err = headscale.ListNodes()
		assert.NoError(c, err)
		assert.Len(c, nodes, 6)
		require.GreaterOrEqual(t, len(nodes), 3, "need at least 3 nodes to avoid panic")
		requireNodeRouteCountWithCollect(c, nodes[0], 1, 1, 1)
		requireNodeRouteCountWithCollect(c, nodes[1], 1, 0, 0)
		requireNodeRouteCountWithCollect(c, nodes[2], 1, 0, 0)
	}, propagationTime, 200*time.Millisecond, "Router 1 approval verification: Should be PRIMARY (available=1, approved=1, subnet=1), others still unapproved (available=1, approved=0, subnet=0)")

	// Verify that the client has routes from the primary machine and can access
	// the webservice.
	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		srs1 = subRouter1.MustStatus()
		srs2 = subRouter2.MustStatus()
		srs3 = subRouter3.MustStatus()
		clientStatus = client.MustStatus()

		srs1PeerStatus = clientStatus.Peer[srs1.Self.PublicKey]
		srs2PeerStatus = clientStatus.Peer[srs2.Self.PublicKey]
		srs3PeerStatus = clientStatus.Peer[srs3.Self.PublicKey]

		assert.NotNil(c, srs1PeerStatus, "Router 1 peer should exist")
		assert.NotNil(c, srs2PeerStatus, "Router 2 peer should exist")
		assert.NotNil(c, srs3PeerStatus, "Router 3 peer should exist")

		if srs1PeerStatus == nil || srs2PeerStatus == nil || srs3PeerStatus == nil {
			return
		}

		assert.True(c, srs1PeerStatus.Online, "Router 1 should be online and serving as PRIMARY")
		assert.True(c, srs2PeerStatus.Online, "Router 2 should be online but NOT serving routes (unapproved)")
		assert.True(c, srs3PeerStatus.Online, "Router 3 should be online but NOT serving routes (unapproved)")

		assert.Nil(c, srs2PeerStatus.PrimaryRoutes)
		assert.Nil(c, srs3PeerStatus.PrimaryRoutes)
		assert.NotNil(c, srs1PeerStatus.PrimaryRoutes)

		requirePeerSubnetRoutesWithCollect(c, srs1PeerStatus, []netip.Prefix{pref})
		requirePeerSubnetRoutesWithCollect(c, srs2PeerStatus, nil)
		requirePeerSubnetRoutesWithCollect(c, srs3PeerStatus, nil)

		if srs1PeerStatus.PrimaryRoutes != nil {
			t.Logf("got list: %v, want in: %v", srs1PeerStatus.PrimaryRoutes.AsSlice(), pref)
			assert.Contains(c,
				srs1PeerStatus.PrimaryRoutes.AsSlice(),
				pref,
			)
		}
	}, propagationTime, 200*time.Millisecond, "Verifying Router 1 is PRIMARY with routes after approval")

	t.Logf("=== Validating connectivity through PRIMARY router 1 (%s) to webservice at %s ===", must.Get(subRouter1.IPv4()).String(), webip.String())
	t.Logf("[%s] Starting test section", time.Now().Format(TimestampFormat))
	t.Logf("  Expected: Traffic flows through router 1 as it's the only approved route")
	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		result, err := client.Curl(weburl)
		assert.NoError(c, err)
		assert.Len(c, result, 13)
	}, propagationTime, 200*time.Millisecond, "Verifying client can reach webservice through router 1")

	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		tr, err := client.Traceroute(webip)
		assert.NoError(c, err)

		ip, err := subRouter1.IPv4()
		if !assert.NoError(c, err, "failed to get IPv4 for subRouter1") {
			return
		}

		assertTracerouteViaIPWithCollect(c, tr, ip)
	}, propagationTime, 200*time.Millisecond, "Verifying traceroute goes through router 1")

	// Validate primary routes table state - router 1 is primary
	validatePrimaryRoutes(t, headscale, &routes.DebugRoutes{
		AvailableRoutes: map[types.NodeID][]netip.Prefix{
			types.NodeID(MustFindNode(subRouter1.Hostname(), nodes).GetId()): {pref},
			// Note: Router 2 and 3 are available but not approved
		},
		PrimaryRoutes: map[string]types.NodeID{
			pref.String(): types.NodeID(MustFindNode(subRouter1.Hostname(), nodes).GetId()),
		},
	}, "Router 1 should be primary for route "+pref.String())

	checkFailureAndPrintRoutes(t, client)

	// Enable route on node 2, now we will have a HA subnet router
	t.Logf("=== Enabling High Availability by approving route on router 2 (%s) ===", subRouter2.Hostname())
	t.Logf("[%s] Starting test section", time.Now().Format(TimestampFormat))
	t.Logf("  Current state: Router 1 is PRIMARY and actively serving traffic")
	t.Logf("  Expected: Router 2 becomes STANDBY (approved but not primary)")
	t.Logf("  Expected: Router 1 remains PRIMARY (no flapping - stability preferred)")
	t.Logf("  Expected: HA is now active - if router 1 fails, router 2 can take over")

	_, err = headscale.ApproveRoutes(
		MustFindNode(subRouter2.Hostname(), nodes).GetId(),
		[]netip.Prefix{pref},
	)
	require.NoError(t, err)

	// Wait for route approval on second subnet router
	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		nodes, err = headscale.ListNodes()
		assert.NoError(c, err)
		assert.Len(c, nodes, 6)

		if len(nodes) >= 3 {
			requireNodeRouteCountWithCollect(c, nodes[0], 1, 1, 1)
			requireNodeRouteCountWithCollect(c, nodes[1], 1, 1, 0)
			requireNodeRouteCountWithCollect(c, nodes[2], 1, 0, 0)
		}
	}, integrationutil.ScaledTimeout(3*time.Second), 200*time.Millisecond, "HA setup verification: Router 2 approved as STANDBY (available=1, approved=1, subnet=0), Router 1 stays PRIMARY (subnet=1)")

	// Verify that the client has routes from the primary machine
	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		srs1 = subRouter1.MustStatus()
		srs2 = subRouter2.MustStatus()
		srs3 = subRouter3.MustStatus()
		clientStatus = client.MustStatus()

		srs1PeerStatus = clientStatus.Peer[srs1.Self.PublicKey]
		srs2PeerStatus = clientStatus.Peer[srs2.Self.PublicKey]
		srs3PeerStatus = clientStatus.Peer[srs3.Self.PublicKey]

		assert.NotNil(c, srs1PeerStatus, "Router 1 peer should exist")
		assert.NotNil(c, srs2PeerStatus, "Router 2 peer should exist")
		assert.NotNil(c, srs3PeerStatus, "Router 3 peer should exist")

		if srs1PeerStatus == nil || srs2PeerStatus == nil || srs3PeerStatus == nil {
			return
		}

		assert.True(c, srs1PeerStatus.Online, "Router 1 should be online and remain PRIMARY")
		assert.True(c, srs2PeerStatus.Online, "Router 2 should be online and now approved as STANDBY")
		assert.True(c, srs3PeerStatus.Online, "Router 3 should be online but still unapproved")

		assert.Nil(c, srs2PeerStatus.PrimaryRoutes)
		assert.Nil(c, srs3PeerStatus.PrimaryRoutes)
		assert.NotNil(c, srs1PeerStatus.PrimaryRoutes)

		requirePeerSubnetRoutesWithCollect(c, srs1PeerStatus, []netip.Prefix{pref})
		requirePeerSubnetRoutesWithCollect(c, srs2PeerStatus, nil)
		requirePeerSubnetRoutesWithCollect(c, srs3PeerStatus, nil)

		if srs1PeerStatus.PrimaryRoutes != nil {
			t.Logf("got list: %v, want in: %v", srs1PeerStatus.PrimaryRoutes.AsSlice(), pref)
			assert.Contains(c,
				srs1PeerStatus.PrimaryRoutes.AsSlice(),
				pref,
			)
		}
	}, propagationTime, 200*time.Millisecond, "Verifying Router 1 remains PRIMARY after Router 2 approval")

	// Validate primary routes table state - router 1 still primary, router 2 approved but standby
	validatePrimaryRoutes(t, headscale, &routes.DebugRoutes{
		AvailableRoutes: map[types.NodeID][]netip.Prefix{
			types.NodeID(MustFindNode(subRouter1.Hostname(), nodes).GetId()): {pref},
			types.NodeID(MustFindNode(subRouter2.Hostname(), nodes).GetId()): {pref},
			// Note: Router 3 is available but not approved
		},
		PrimaryRoutes: map[string]types.NodeID{
			pref.String(): types.NodeID(MustFindNode(subRouter1.Hostname(), nodes).GetId()),
		},
	}, "Router 1 should remain primary after router 2 approval")

	checkFailureAndPrintRoutes(t, client)

	t.Logf("=== Validating HA configuration - Router 1 PRIMARY, Router 2 STANDBY ===")
	t.Logf("[%s] Starting test section", time.Now().Format(TimestampFormat))
	t.Logf("  Current routing: Traffic through router 1 (%s) to %s", must.Get(subRouter1.IPv4()), webip.String())
	t.Logf("  Expected: Router 1 continues to handle all traffic (no change from before)")
	t.Logf("  Expected: Router 2 is ready to take over if router 1 fails")
	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		result, err := client.Curl(weburl)
		assert.NoError(c, err)
		assert.Len(c, result, 13)
	}, propagationTime, 200*time.Millisecond, "Verifying client can reach webservice through router 1 in HA mode")

	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		tr, err := client.Traceroute(webip)
		assert.NoError(c, err)

		ip, err := subRouter1.IPv4()
		if !assert.NoError(c, err, "failed to get IPv4 for subRouter1") {
			return
		}

		assertTracerouteViaIPWithCollect(c, tr, ip)
	}, propagationTime, 200*time.Millisecond, "Verifying traceroute still goes through router 1 in HA mode")

	// Validate primary routes table state - router 1 primary, router 2 approved (standby)
	validatePrimaryRoutes(t, headscale, &routes.DebugRoutes{
		AvailableRoutes: map[types.NodeID][]netip.Prefix{
			types.NodeID(MustFindNode(subRouter1.Hostname(), nodes).GetId()): {pref},
			types.NodeID(MustFindNode(subRouter2.Hostname(), nodes).GetId()): {pref},
			// Note: Router 3 is available but not approved
		},
		PrimaryRoutes: map[string]types.NodeID{
			pref.String(): types.NodeID(MustFindNode(subRouter1.Hostname(), nodes).GetId()),
		},
	}, "Router 1 primary with router 2 as standby")

	checkFailureAndPrintRoutes(t, client)

	// Enable route on node 3, now we will have a second standby and all will
	// be enabled.
	t.Logf("=== Adding second STANDBY router by approving route on router 3 (%s) ===", subRouter3.Hostname())
	t.Logf("[%s] Starting test section", time.Now().Format(TimestampFormat))
	t.Logf("  Current state: Router 1 PRIMARY, Router 2 STANDBY")
	t.Logf("  Expected: Router 3 becomes second STANDBY (approved but not primary)")
	t.Logf("  Expected: Router 1 remains PRIMARY, Router 2 remains first STANDBY")
	t.Logf("  Expected: Full HA configuration with 1 PRIMARY + 2 STANDBY routers")

	_, err = headscale.ApproveRoutes(
		MustFindNode(subRouter3.Hostname(), nodes).GetId(),
		[]netip.Prefix{pref},
	)
	require.NoError(t, err)

	// Wait for route approval on third subnet router
	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		nodes, err = headscale.ListNodes()
		assert.NoError(c, err)
		assert.Len(c, nodes, 6)
		require.GreaterOrEqual(t, len(nodes), 3, "need at least 3 nodes to avoid panic")
		requireNodeRouteCountWithCollect(c, nodes[0], 1, 1, 1)
		requireNodeRouteCountWithCollect(c, nodes[1], 1, 1, 0)
		requireNodeRouteCountWithCollect(c, nodes[2], 1, 1, 0)
	}, integrationutil.ScaledTimeout(3*time.Second), 200*time.Millisecond, "Full HA verification: Router 3 approved as second STANDBY (available=1, approved=1, subnet=0), Router 1 PRIMARY, Router 2 first STANDBY")

	// Verify that the client has routes from the primary machine
	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		srs1 = subRouter1.MustStatus()
		srs2 = subRouter2.MustStatus()
		srs3 = subRouter3.MustStatus()
		clientStatus = client.MustStatus()

		srs1PeerStatus = clientStatus.Peer[srs1.Self.PublicKey]
		srs2PeerStatus = clientStatus.Peer[srs2.Self.PublicKey]
		srs3PeerStatus = clientStatus.Peer[srs3.Self.PublicKey]

		assert.NotNil(c, srs1PeerStatus, "Router 1 peer should exist")
		assert.NotNil(c, srs2PeerStatus, "Router 2 peer should exist")
		assert.NotNil(c, srs3PeerStatus, "Router 3 peer should exist")

		if srs1PeerStatus == nil || srs2PeerStatus == nil || srs3PeerStatus == nil {
			return
		}

		assert.True(c, srs1PeerStatus.Online, "Router 1 should be online and remain PRIMARY")
		assert.True(c, srs2PeerStatus.Online, "Router 2 should be online as first STANDBY")
		assert.True(c, srs3PeerStatus.Online, "Router 3 should be online as second STANDBY")

		assert.Nil(c, srs2PeerStatus.PrimaryRoutes)
		assert.Nil(c, srs3PeerStatus.PrimaryRoutes)
		assert.NotNil(c, srs1PeerStatus.PrimaryRoutes)

		requirePeerSubnetRoutesWithCollect(c, srs1PeerStatus, []netip.Prefix{pref})
		requirePeerSubnetRoutesWithCollect(c, srs2PeerStatus, nil)
		requirePeerSubnetRoutesWithCollect(c, srs3PeerStatus, nil)

		if srs1PeerStatus.PrimaryRoutes != nil {
			t.Logf("got list: %v, want in: %v", srs1PeerStatus.PrimaryRoutes.AsSlice(), pref)
			assert.Contains(c,
				srs1PeerStatus.PrimaryRoutes.AsSlice(),
				pref,
			)
		}
	}, propagationTime, 200*time.Millisecond, "Verifying full HA with 3 routers: Router 1 PRIMARY, Routers 2 & 3 STANDBY")

	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		result, err := client.Curl(weburl)
		assert.NoError(c, err)
		assert.Len(c, result, 13)
	}, propagationTime, 200*time.Millisecond, "Verifying client can reach webservice through router 1 with full HA")

	// Wait for traceroute to work correctly through the expected router
	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		tr, err := client.Traceroute(webip)
		assert.NoError(c, err)

		// Get the expected router IP - use a more robust approach to handle temporary disconnections
		ips, err := subRouter1.IPs()
		assert.NoError(c, err)
		assert.NotEmpty(c, ips, "subRouter1 should have IP addresses")

		var expectedIP netip.Addr

		for _, ip := range ips {
			if ip.Is4() {
				expectedIP = ip
				break
			}
		}

		assert.True(c, expectedIP.IsValid(), "subRouter1 should have a valid IPv4 address")

		assertTracerouteViaIPWithCollect(c, tr, expectedIP)
	}, propagationTime, 200*time.Millisecond, "Verifying traffic still flows through PRIMARY router 1 with full HA setup active")

	// Validate primary routes table state - all 3 routers approved, router 1 still primary
	validatePrimaryRoutes(t, headscale, &routes.DebugRoutes{
		AvailableRoutes: map[types.NodeID][]netip.Prefix{
			types.NodeID(MustFindNode(subRouter1.Hostname(), nodes).GetId()): {pref},
			types.NodeID(MustFindNode(subRouter2.Hostname(), nodes).GetId()): {pref},
			types.NodeID(MustFindNode(subRouter3.Hostname(), nodes).GetId()): {pref},
		},
		PrimaryRoutes: map[string]types.NodeID{
			pref.String(): types.NodeID(MustFindNode(subRouter1.Hostname(), nodes).GetId()),
		},
	}, "Router 1 primary with all 3 routers approved")

	checkFailureAndPrintRoutes(t, client)

	// Take down the current primary
	t.Logf("=== FAILOVER TEST: Taking down PRIMARY router 1 (%s) ===", subRouter1.Hostname())
	t.Logf("[%s] Starting test section", time.Now().Format(TimestampFormat))
	t.Logf("  Current state: Router 1 PRIMARY (serving traffic), Router 2 & 3 STANDBY")
	t.Logf("  Action: Shutting down router 1 to simulate failure")
	t.Logf("  Expected: Router 2 (%s) should automatically become new PRIMARY", subRouter2.Hostname())
	t.Logf("  Expected: Router 3 remains STANDBY")
	t.Logf("  Expected: Traffic seamlessly fails over to router 2")

	err = subRouter1.Down()
	require.NoError(t, err)

	// Wait for router status changes after r1 goes down
	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		srs2 = subRouter2.MustStatus()
		clientStatus = client.MustStatus()

		srs1PeerStatus = clientStatus.Peer[srs1.Self.PublicKey]
		srs2PeerStatus = clientStatus.Peer[srs2.Self.PublicKey]
		srs3PeerStatus = clientStatus.Peer[srs3.Self.PublicKey]

		assert.NotNil(c, srs1PeerStatus, "Router 1 peer should exist")
		assert.NotNil(c, srs2PeerStatus, "Router 2 peer should exist")
		assert.NotNil(c, srs3PeerStatus, "Router 3 peer should exist")

		if srs1PeerStatus == nil || srs2PeerStatus == nil || srs3PeerStatus == nil {
			return
		}

		assert.False(c, srs1PeerStatus.Online, "r1 should be offline")
		assert.True(c, srs2PeerStatus.Online, "r2 should be online")
		assert.True(c, srs3PeerStatus.Online, "r3 should be online")

		assert.Nil(c, srs1PeerStatus.PrimaryRoutes)
		assert.NotNil(c, srs2PeerStatus.PrimaryRoutes)
		assert.Nil(c, srs3PeerStatus.PrimaryRoutes)

		requirePeerSubnetRoutesWithCollect(c, srs1PeerStatus, nil)
		requirePeerSubnetRoutesWithCollect(c, srs2PeerStatus, []netip.Prefix{pref})
		requirePeerSubnetRoutesWithCollect(c, srs3PeerStatus, nil)

		if srs2PeerStatus.PrimaryRoutes != nil {
			assert.Contains(c,
				srs2PeerStatus.PrimaryRoutes.AsSlice(),
				pref,
			)
		}
	}, propagationTime, 200*time.Millisecond, "Failover verification: Router 1 offline, Router 2 should be new PRIMARY with routes, Router 3 still STANDBY")

	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		result, err := client.Curl(weburl)
		assert.NoError(c, err)
		assert.Len(c, result, 13)
	}, propagationTime, 200*time.Millisecond, "Verifying client can reach webservice through router 2 after failover")

	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		tr, err := client.Traceroute(webip)
		assert.NoError(c, err)

		ip, err := subRouter2.IPv4()
		if !assert.NoError(c, err, "failed to get IPv4 for subRouter2") {
			return
		}

		assertTracerouteViaIPWithCollect(c, tr, ip)
	}, propagationTime, 200*time.Millisecond, "Verifying traceroute goes through router 2 after failover")

	// Validate primary routes table state - router 2 is now primary after router 1 failure
	validatePrimaryRoutes(t, headscale, &routes.DebugRoutes{
		AvailableRoutes: map[types.NodeID][]netip.Prefix{
			// Router 1 is disconnected, so not in AvailableRoutes
			types.NodeID(MustFindNode(subRouter2.Hostname(), nodes).GetId()): {pref},
			types.NodeID(MustFindNode(subRouter3.Hostname(), nodes).GetId()): {pref},
		},
		PrimaryRoutes: map[string]types.NodeID{
			pref.String(): types.NodeID(MustFindNode(subRouter2.Hostname(), nodes).GetId()),
		},
	}, "Router 2 should be primary after router 1 failure")

	checkFailureAndPrintRoutes(t, client)

	// Take down subnet router 2, leaving none available
	t.Logf("=== FAILOVER TEST: Taking down NEW PRIMARY router 2 (%s) ===", subRouter2.Hostname())
	t.Logf("[%s] Starting test section", time.Now().Format(TimestampFormat))
	t.Logf("  Current state: Router 1 OFFLINE, Router 2 PRIMARY (serving traffic), Router 3 STANDBY")
	t.Logf("  Action: Shutting down router 2 to simulate cascading failure")
	t.Logf("  Expected: Router 3 (%s) should become new PRIMARY (last remaining router)", subRouter3.Hostname())
	t.Logf("  Expected: With only 1 router left, HA is effectively disabled")
	t.Logf("  Expected: Traffic continues through router 3")

	err = subRouter2.Down()
	require.NoError(t, err)

	// Wait for router status changes after r2 goes down
	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		clientStatus, err = client.Status()
		assert.NoError(c, err)

		srs1PeerStatus = clientStatus.Peer[srs1.Self.PublicKey]
		srs2PeerStatus = clientStatus.Peer[srs2.Self.PublicKey]
		srs3PeerStatus = clientStatus.Peer[srs3.Self.PublicKey]

		assert.NotNil(c, srs1PeerStatus, "Router 1 peer should exist")
		assert.NotNil(c, srs2PeerStatus, "Router 2 peer should exist")
		assert.NotNil(c, srs3PeerStatus, "Router 3 peer should exist")

		if srs1PeerStatus == nil || srs2PeerStatus == nil || srs3PeerStatus == nil {
			return
		}

		assert.False(c, srs1PeerStatus.Online, "Router 1 should still be offline")
		assert.False(c, srs2PeerStatus.Online, "Router 2 should now be offline after failure")
		assert.True(c, srs3PeerStatus.Online, "Router 3 should be online and taking over as PRIMARY")

		assert.Nil(c, srs1PeerStatus.PrimaryRoutes)
		assert.Nil(c, srs2PeerStatus.PrimaryRoutes)
		assert.NotNil(c, srs3PeerStatus.PrimaryRoutes)

		requirePeerSubnetRoutesWithCollect(c, srs1PeerStatus, nil)
		requirePeerSubnetRoutesWithCollect(c, srs2PeerStatus, nil)
		requirePeerSubnetRoutesWithCollect(c, srs3PeerStatus, []netip.Prefix{pref})
	}, propagationTime, 200*time.Millisecond, "Second failover verification: Router 1 & 2 offline, Router 3 should be new PRIMARY (last router standing) with routes")

	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		result, err := client.Curl(weburl)
		assert.NoError(c, err)
		assert.Len(c, result, 13)
	}, propagationTime, 200*time.Millisecond, "Verifying client can reach webservice through router 3 after second failover")

	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		tr, err := client.Traceroute(webip)
		assert.NoError(c, err)

		ip, err := subRouter3.IPv4()
		if !assert.NoError(c, err, "failed to get IPv4 for subRouter3") {
			return
		}

		assertTracerouteViaIPWithCollect(c, tr, ip)
	}, propagationTime, 200*time.Millisecond, "Verifying traceroute goes through router 3 after second failover")

	// Validate primary routes table state - router 3 is now primary after router 2 failure
	validatePrimaryRoutes(t, headscale, &routes.DebugRoutes{
		AvailableRoutes: map[types.NodeID][]netip.Prefix{
			// Routers 1 and 2 are disconnected, so not in AvailableRoutes
			types.NodeID(MustFindNode(subRouter3.Hostname(), nodes).GetId()): {pref},
		},
		PrimaryRoutes: map[string]types.NodeID{
			pref.String(): types.NodeID(MustFindNode(subRouter3.Hostname(), nodes).GetId()),
		},
	}, "Router 3 should be primary after router 2 failure")

	checkFailureAndPrintRoutes(t, client)

	// Bring up subnet router 1, making the route available from there.
	t.Logf("=== RECOVERY TEST: Bringing router 1 (%s) back online ===", subRouter1.Hostname())
	t.Logf("[%s] Starting test section", time.Now().Format(TimestampFormat))
	t.Logf("  Current state: Router 1 OFFLINE, Router 2 OFFLINE, Router 3 PRIMARY (only router)")
	t.Logf("  Action: Starting router 1 to restore HA capability")
	t.Logf("  Expected: Router 3 remains PRIMARY (stability - no unnecessary failover)")
	t.Logf("  Expected: Router 1 becomes STANDBY (ready for HA)")
	t.Logf("  Expected: HA is restored with 2 routers available")

	err = subRouter1.Up()
	require.NoError(t, err)

	// Wait for router status changes after r1 comes back up
	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		clientStatus, err = client.Status()
		assert.NoError(c, err)

		srs1PeerStatus = clientStatus.Peer[srs1.Self.PublicKey]
		srs2PeerStatus = clientStatus.Peer[srs2.Self.PublicKey]
		srs3PeerStatus = clientStatus.Peer[srs3.Self.PublicKey]

		assert.NotNil(c, srs1PeerStatus, "Router 1 peer should exist")
		assert.NotNil(c, srs2PeerStatus, "Router 2 peer should exist")
		assert.NotNil(c, srs3PeerStatus, "Router 3 peer should exist")

		if srs1PeerStatus == nil || srs2PeerStatus == nil || srs3PeerStatus == nil {
			return
		}

		assert.True(c, srs1PeerStatus.Online, "Router 1 should be back online as STANDBY")
		assert.False(c, srs2PeerStatus.Online, "Router 2 should still be offline")
		assert.True(c, srs3PeerStatus.Online, "Router 3 should remain online as PRIMARY")

		assert.Nil(c, srs1PeerStatus.PrimaryRoutes)
		assert.Nil(c, srs2PeerStatus.PrimaryRoutes)
		assert.NotNil(c, srs3PeerStatus.PrimaryRoutes)

		requirePeerSubnetRoutesWithCollect(c, srs1PeerStatus, nil)
		requirePeerSubnetRoutesWithCollect(c, srs2PeerStatus, nil)
		requirePeerSubnetRoutesWithCollect(c, srs3PeerStatus, []netip.Prefix{pref})

		if srs3PeerStatus.PrimaryRoutes != nil {
			assert.Contains(c,
				srs3PeerStatus.PrimaryRoutes.AsSlice(),
				pref,
			)
		}
	}, propagationTime, 200*time.Millisecond, "Recovery verification: Router 1 back online as STANDBY, Router 3 remains PRIMARY (no flapping) with routes")

	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		result, err := client.Curl(weburl)
		assert.NoError(c, err)
		assert.Len(c, result, 13)
	}, propagationTime, 200*time.Millisecond, "Verifying client can still reach webservice through router 3 after router 1 recovery")

	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		tr, err := client.Traceroute(webip)
		assert.NoError(c, err)

		ip, err := subRouter3.IPv4()
		if !assert.NoError(c, err, "failed to get IPv4 for subRouter3") {
			return
		}

		assertTracerouteViaIPWithCollect(c, tr, ip)
	}, propagationTime, 200*time.Millisecond, "Verifying traceroute still goes through router 3 after router 1 recovery")

	// Validate primary routes table state - router 3 remains primary after router 1 comes back
	validatePrimaryRoutes(t, headscale, &routes.DebugRoutes{
		AvailableRoutes: map[types.NodeID][]netip.Prefix{
			types.NodeID(MustFindNode(subRouter1.Hostname(), nodes).GetId()): {pref},
			// Router 2 is still disconnected
			types.NodeID(MustFindNode(subRouter3.Hostname(), nodes).GetId()): {pref},
		},
		PrimaryRoutes: map[string]types.NodeID{
			pref.String(): types.NodeID(MustFindNode(subRouter3.Hostname(), nodes).GetId()),
		},
	}, "Router 3 should remain primary after router 1 recovery")

	checkFailureAndPrintRoutes(t, client)

	// Bring up subnet router 2, should result in no change.
	t.Logf("=== FULL RECOVERY TEST: Bringing router 2 (%s) back online ===", subRouter2.Hostname())
	t.Logf("[%s] Starting test section", time.Now().Format(TimestampFormat))
	t.Logf("  Current state: Router 1 STANDBY, Router 2 OFFLINE, Router 3 PRIMARY")
	t.Logf("  Action: Starting router 2 to restore full HA (3 routers)")
	t.Logf("  Expected: Router 3 (%s) remains PRIMARY (stability - avoid unnecessary failovers)", subRouter3.Hostname())
	t.Logf("  Expected: Router 1 (%s) remains first STANDBY", subRouter1.Hostname())
	t.Logf("  Expected: Router 2 (%s) becomes second STANDBY", subRouter2.Hostname())
	t.Logf("  Expected: Full HA restored with all 3 routers online")

	err = subRouter2.Up()
	require.NoError(t, err)

	// Wait for nodestore batch processing to complete and online status to be updated
	// NodeStore batching timeout is 500ms, so we wait up to 10 seconds for all routers to be online
	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		clientStatus, err = client.Status()
		assert.NoError(c, err)

		srs1PeerStatus = clientStatus.Peer[srs1.Self.PublicKey]
		srs2PeerStatus = clientStatus.Peer[srs2.Self.PublicKey]
		srs3PeerStatus = clientStatus.Peer[srs3.Self.PublicKey]

		assert.NotNil(c, srs1PeerStatus, "Router 1 peer should exist")
		assert.NotNil(c, srs2PeerStatus, "Router 2 peer should exist")
		assert.NotNil(c, srs3PeerStatus, "Router 3 peer should exist")

		if srs1PeerStatus == nil || srs2PeerStatus == nil || srs3PeerStatus == nil {
			return
		}

		assert.True(c, srs1PeerStatus.Online, "Router 1 should be online as STANDBY")
		assert.True(c, srs2PeerStatus.Online, "Router 2 should be back online as STANDBY")
		assert.True(c, srs3PeerStatus.Online, "Router 3 should remain online as PRIMARY")

		assert.Nil(c, srs1PeerStatus.PrimaryRoutes)
		assert.Nil(c, srs2PeerStatus.PrimaryRoutes)
		assert.NotNil(c, srs3PeerStatus.PrimaryRoutes)

		requirePeerSubnetRoutesWithCollect(c, srs1PeerStatus, nil)
		requirePeerSubnetRoutesWithCollect(c, srs2PeerStatus, nil)
		requirePeerSubnetRoutesWithCollect(c, srs3PeerStatus, []netip.Prefix{pref})

		if srs3PeerStatus.PrimaryRoutes != nil {
			assert.Contains(c,
				srs3PeerStatus.PrimaryRoutes.AsSlice(),
				pref,
			)
		}
	}, integrationutil.ScaledTimeout(10*time.Second), 500*time.Millisecond, "Full recovery verification: All 3 routers online, Router 3 remains PRIMARY (no flapping) with routes")

	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		result, err := client.Curl(weburl)
		assert.NoError(c, err)
		assert.Len(c, result, 13)
	}, propagationTime, 200*time.Millisecond, "Verifying client can reach webservice through router 3 after full recovery")

	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		tr, err := client.Traceroute(webip)
		assert.NoError(c, err)

		ip, err := subRouter3.IPv4()
		if !assert.NoError(c, err, "failed to get IPv4 for subRouter3") {
			return
		}

		assertTracerouteViaIPWithCollect(c, tr, ip)
	}, propagationTime, 200*time.Millisecond, "Verifying traceroute goes through router 3 after full recovery")

	// Validate primary routes table state - router 3 remains primary after all routers back online
	validatePrimaryRoutes(t, headscale, &routes.DebugRoutes{
		AvailableRoutes: map[types.NodeID][]netip.Prefix{
			types.NodeID(MustFindNode(subRouter1.Hostname(), nodes).GetId()): {pref},
			types.NodeID(MustFindNode(subRouter2.Hostname(), nodes).GetId()): {pref},
			types.NodeID(MustFindNode(subRouter3.Hostname(), nodes).GetId()): {pref},
		},
		PrimaryRoutes: map[string]types.NodeID{
			pref.String(): types.NodeID(MustFindNode(subRouter3.Hostname(), nodes).GetId()),
		},
	}, "Router 3 should remain primary after full recovery")

	checkFailureAndPrintRoutes(t, client)

	t.Logf("=== ROUTE DISABLE TEST: Removing approved route from PRIMARY router 3 (%s) ===", subRouter3.Hostname())
	t.Logf("[%s] Starting test section", time.Now().Format(TimestampFormat))
	t.Logf("  Current state: Router 1 STANDBY, Router 2 STANDBY, Router 3 PRIMARY")
	t.Logf("  Action: Disabling route approval on router 3 (route still advertised but not approved)")
	t.Logf("  Expected: Router 1 (%s) should become new PRIMARY (lowest ID with approved route)", subRouter1.Hostname())
	t.Logf("  Expected: Router 2 (%s) remains STANDBY", subRouter2.Hostname())
	t.Logf("  Expected: Router 3 (%s) goes to advertised-only state (no longer serving)", subRouter3.Hostname())
	_, err = headscale.ApproveRoutes(MustFindNode(subRouter3.Hostname(), nodes).GetId(), []netip.Prefix{})

	// Wait for nodestore batch processing and route state changes to complete
	// NodeStore batching timeout is 500ms, so we wait up to 10 seconds for route failover
	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		nodes, err = headscale.ListNodes()
		assert.NoError(c, err)
		assert.Len(c, nodes, 6)

		// After disabling route on r3, r1 should become primary with 1 subnet route
		requireNodeRouteCountWithCollect(c, MustFindNode(subRouter1.Hostname(), nodes), 1, 1, 1)
		requireNodeRouteCountWithCollect(c, MustFindNode(subRouter2.Hostname(), nodes), 1, 1, 0)
		requireNodeRouteCountWithCollect(c, MustFindNode(subRouter3.Hostname(), nodes), 1, 0, 0)
	}, integrationutil.ScaledTimeout(10*time.Second), 500*time.Millisecond, "Route disable verification: Router 3 route disabled, Router 1 should be new PRIMARY, Router 2 STANDBY")

	// Verify that the route is announced from subnet router 1
	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		clientStatus, err = client.Status()
		assert.NoError(c, err)

		srs1PeerStatus = clientStatus.Peer[srs1.Self.PublicKey]
		srs2PeerStatus = clientStatus.Peer[srs2.Self.PublicKey]
		srs3PeerStatus = clientStatus.Peer[srs3.Self.PublicKey]

		assert.NotNil(c, srs1PeerStatus, "Router 1 peer should exist")
		assert.NotNil(c, srs2PeerStatus, "Router 2 peer should exist")
		assert.NotNil(c, srs3PeerStatus, "Router 3 peer should exist")

		if srs1PeerStatus == nil || srs2PeerStatus == nil || srs3PeerStatus == nil {
			return
		}

		assert.NotNil(c, srs1PeerStatus.PrimaryRoutes)
		assert.Nil(c, srs2PeerStatus.PrimaryRoutes)
		assert.Nil(c, srs3PeerStatus.PrimaryRoutes)

		requirePeerSubnetRoutesWithCollect(c, srs1PeerStatus, []netip.Prefix{pref})
		requirePeerSubnetRoutesWithCollect(c, srs2PeerStatus, nil)
		requirePeerSubnetRoutesWithCollect(c, srs3PeerStatus, nil)

		if srs1PeerStatus.PrimaryRoutes != nil {
			assert.Contains(c,
				srs1PeerStatus.PrimaryRoutes.AsSlice(),
				pref,
			)
		}
	}, propagationTime, 200*time.Millisecond, "Verifying Router 1 becomes PRIMARY after Router 3 route disabled")

	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		result, err := client.Curl(weburl)
		assert.NoError(c, err)
		assert.Len(c, result, 13)
	}, propagationTime, 200*time.Millisecond, "Verifying client can reach webservice through router 1 after route disable")

	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		tr, err := client.Traceroute(webip)
		assert.NoError(c, err)

		ip, err := subRouter1.IPv4()
		if !assert.NoError(c, err, "failed to get IPv4 for subRouter1") {
			return
		}

		assertTracerouteViaIPWithCollect(c, tr, ip)
	}, propagationTime, 200*time.Millisecond, "Verifying traceroute goes through router 1 after route disable")

	// Validate primary routes table state - router 1 is primary after router 3 route disabled
	validatePrimaryRoutes(t, headscale, &routes.DebugRoutes{
		AvailableRoutes: map[types.NodeID][]netip.Prefix{
			types.NodeID(MustFindNode(subRouter1.Hostname(), nodes).GetId()): {pref},
			types.NodeID(MustFindNode(subRouter2.Hostname(), nodes).GetId()): {pref},
			// Router 3's route is no longer approved, so not in AvailableRoutes
		},
		PrimaryRoutes: map[string]types.NodeID{
			pref.String(): types.NodeID(MustFindNode(subRouter1.Hostname(), nodes).GetId()),
		},
	}, "Router 1 should be primary after router 3 route disabled")

	checkFailureAndPrintRoutes(t, client)

	// Disable the route of subnet router 1, making it failover to 2
	t.Logf("=== ROUTE DISABLE TEST: Removing approved route from NEW PRIMARY router 1 (%s) ===", subRouter1.Hostname())
	t.Logf("[%s] Starting test section", time.Now().Format(TimestampFormat))
	t.Logf("  Current state: Router 1 PRIMARY, Router 2 STANDBY, Router 3 advertised-only")
	t.Logf("  Action: Disabling route approval on router 1")
	t.Logf("  Expected: Router 2 (%s) should become new PRIMARY (only remaining approved route)", subRouter2.Hostname())
	t.Logf("  Expected: Router 1 (%s) goes to advertised-only state", subRouter1.Hostname())
	t.Logf("  Expected: Router 3 (%s) remains advertised-only", subRouter3.Hostname())
	_, err = headscale.ApproveRoutes(MustFindNode(subRouter1.Hostname(), nodes).GetId(), []netip.Prefix{})

	// Wait for nodestore batch processing and route state changes to complete
	// NodeStore batching timeout is 500ms, so we wait up to 10 seconds for route failover
	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		nodes, err = headscale.ListNodes()
		assert.NoError(c, err)
		assert.Len(c, nodes, 6)

		// After disabling route on r1, r2 should become primary with 1 subnet route
		requireNodeRouteCountWithCollect(c, MustFindNode(subRouter1.Hostname(), nodes), 1, 0, 0)
		requireNodeRouteCountWithCollect(c, MustFindNode(subRouter2.Hostname(), nodes), 1, 1, 1)
		requireNodeRouteCountWithCollect(c, MustFindNode(subRouter3.Hostname(), nodes), 1, 0, 0)
	}, integrationutil.ScaledTimeout(10*time.Second), 500*time.Millisecond, "Second route disable verification: Router 1 route disabled, Router 2 should be new PRIMARY")

	// Verify that the route is announced from subnet router 1
	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		clientStatus, err = client.Status()
		assert.NoError(c, err)

		srs1PeerStatus = clientStatus.Peer[srs1.Self.PublicKey]
		srs2PeerStatus = clientStatus.Peer[srs2.Self.PublicKey]
		srs3PeerStatus = clientStatus.Peer[srs3.Self.PublicKey]

		assert.NotNil(c, srs1PeerStatus, "Router 1 peer should exist")
		assert.NotNil(c, srs2PeerStatus, "Router 2 peer should exist")
		assert.NotNil(c, srs3PeerStatus, "Router 3 peer should exist")

		if srs1PeerStatus == nil || srs2PeerStatus == nil || srs3PeerStatus == nil {
			return
		}

		assert.Nil(c, srs1PeerStatus.PrimaryRoutes)
		assert.NotNil(c, srs2PeerStatus.PrimaryRoutes)
		assert.Nil(c, srs3PeerStatus.PrimaryRoutes)

		requirePeerSubnetRoutesWithCollect(c, srs1PeerStatus, nil)
		requirePeerSubnetRoutesWithCollect(c, srs2PeerStatus, []netip.Prefix{pref})
		requirePeerSubnetRoutesWithCollect(c, srs3PeerStatus, nil)

		if srs2PeerStatus.PrimaryRoutes != nil {
			assert.Contains(c,
				srs2PeerStatus.PrimaryRoutes.AsSlice(),
				pref,
			)
		}
	}, propagationTime, 200*time.Millisecond, "Verifying Router 2 becomes PRIMARY after Router 1 route disabled")

	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		result, err := client.Curl(weburl)
		assert.NoError(c, err)
		assert.Len(c, result, 13)
	}, propagationTime, 200*time.Millisecond, "Verifying client can reach webservice through router 2 after second route disable")

	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		tr, err := client.Traceroute(webip)
		assert.NoError(c, err)

		ip, err := subRouter2.IPv4()
		if !assert.NoError(c, err, "failed to get IPv4 for subRouter2") {
			return
		}

		assertTracerouteViaIPWithCollect(c, tr, ip)
	}, propagationTime, 200*time.Millisecond, "Verifying traceroute goes through router 2 after second route disable")

	// Validate primary routes table state - router 2 is primary after router 1 route disabled
	validatePrimaryRoutes(t, headscale, &routes.DebugRoutes{
		AvailableRoutes: map[types.NodeID][]netip.Prefix{
			// Router 1's route is no longer approved, so not in AvailableRoutes
			types.NodeID(MustFindNode(subRouter2.Hostname(), nodes).GetId()): {pref},
			// Router 3's route is still not approved
		},
		PrimaryRoutes: map[string]types.NodeID{
			pref.String(): types.NodeID(MustFindNode(subRouter2.Hostname(), nodes).GetId()),
		},
	}, "Router 2 should be primary after router 1 route disabled")

	checkFailureAndPrintRoutes(t, client)

	// enable the route of subnet router 1, no change expected
	t.Logf("=== ROUTE RE-ENABLE TEST: Re-approving route on router 1 (%s) ===", subRouter1.Hostname())
	t.Logf("[%s] Starting test section", time.Now().Format(TimestampFormat))
	t.Logf("  Current state: Router 1 advertised-only, Router 2 PRIMARY, Router 3 advertised-only")
	t.Logf("  Action: Re-enabling route approval on router 1")
	t.Logf("  Expected: Router 2 (%s) remains PRIMARY (stability - no unnecessary flapping)", subRouter2.Hostname())
	t.Logf("  Expected: Router 1 (%s) becomes STANDBY (approved but not primary)", subRouter1.Hostname())
	t.Logf("  Expected: HA fully restored with Router 2 PRIMARY and Router 1 STANDBY")

	r1Node := MustFindNode(subRouter1.Hostname(), nodes)
	_, err = headscale.ApproveRoutes(
		r1Node.GetId(),
		util.MustStringsToPrefixes(r1Node.GetAvailableRoutes()),
	)

	// Wait for route state changes after re-enabling r1
	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		nodes, err = headscale.ListNodes()
		assert.NoError(c, err)
		assert.Len(c, nodes, 6)

		requireNodeRouteCountWithCollect(c, MustFindNode(subRouter1.Hostname(), nodes), 1, 1, 0)
		requireNodeRouteCountWithCollect(c, MustFindNode(subRouter2.Hostname(), nodes), 1, 1, 1)
		requireNodeRouteCountWithCollect(c, MustFindNode(subRouter3.Hostname(), nodes), 1, 0, 0)
	}, propagationTime, 200*time.Millisecond, "Re-enable verification: Router 1 approved as STANDBY, Router 2 remains PRIMARY (no flapping), full HA restored")

	// Verify that the route is announced from subnet router 1
	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		clientStatus, err = client.Status()
		assert.NoError(c, err)

		srs1PeerStatus = clientStatus.Peer[srs1.Self.PublicKey]
		srs2PeerStatus = clientStatus.Peer[srs2.Self.PublicKey]
		srs3PeerStatus = clientStatus.Peer[srs3.Self.PublicKey]

		assert.NotNil(c, srs1PeerStatus, "Router 1 peer should exist")
		assert.NotNil(c, srs2PeerStatus, "Router 2 peer should exist")
		assert.NotNil(c, srs3PeerStatus, "Router 3 peer should exist")

		if srs1PeerStatus == nil || srs2PeerStatus == nil || srs3PeerStatus == nil {
			return
		}

		assert.Nil(c, srs1PeerStatus.PrimaryRoutes)
		assert.NotNil(c, srs2PeerStatus.PrimaryRoutes)
		assert.Nil(c, srs3PeerStatus.PrimaryRoutes)

		if srs2PeerStatus.PrimaryRoutes != nil {
			assert.Contains(c,
				srs2PeerStatus.PrimaryRoutes.AsSlice(),
				pref,
			)
		}
	}, propagationTime, 200*time.Millisecond, "Verifying Router 2 remains PRIMARY after Router 1 route re-enabled")

	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		result, err := client.Curl(weburl)
		assert.NoError(c, err)
		assert.Len(c, result, 13)
	}, propagationTime, 200*time.Millisecond, "Verifying client can reach webservice through router 2 after route re-enable")

	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		tr, err := client.Traceroute(webip)
		assert.NoError(c, err)

		ip, err := subRouter2.IPv4()
		if !assert.NoError(c, err, "failed to get IPv4 for subRouter2") {
			return
		}

		assertTracerouteViaIPWithCollect(c, tr, ip)
	}, propagationTime, 200*time.Millisecond, "Verifying traceroute still goes through router 2 after route re-enable")

	// Validate primary routes table state after router 1 re-approval
	validatePrimaryRoutes(t, headscale, &routes.DebugRoutes{
		AvailableRoutes: map[types.NodeID][]netip.Prefix{
			types.NodeID(MustFindNode(subRouter1.Hostname(), nodes).GetId()): {pref},
			types.NodeID(MustFindNode(subRouter2.Hostname(), nodes).GetId()): {pref},
			// Router 3 route is still not approved
		},
		PrimaryRoutes: map[string]types.NodeID{
			pref.String(): types.NodeID(MustFindNode(subRouter2.Hostname(), nodes).GetId()),
		},
	}, "Router 2 should remain primary after router 1 re-approval")

	checkFailureAndPrintRoutes(t, client)

	// Enable route on node 3, we now have all routes re-enabled
	t.Logf("=== ROUTE RE-ENABLE TEST: Re-approving route on router 3 (%s) - Full HA Restoration ===", subRouter3.Hostname())
	t.Logf("[%s] Starting test section", time.Now().Format(TimestampFormat))
	t.Logf("  Current state: Router 1 STANDBY, Router 2 PRIMARY, Router 3 advertised-only")
	t.Logf("  Action: Re-enabling route approval on router 3")
	t.Logf("  Expected: Router 2 (%s) remains PRIMARY (stability preferred)", subRouter2.Hostname())
	t.Logf("  Expected: Routers 1 & 3 are both STANDBY")
	t.Logf("  Expected: Full HA restored with all 3 routers available")

	r3Node := MustFindNode(subRouter3.Hostname(), nodes)
	_, err = headscale.ApproveRoutes(
		r3Node.GetId(),
		util.MustStringsToPrefixes(r3Node.GetAvailableRoutes()),
	)

	// Wait for route state changes after re-enabling r3
	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		nodes, err = headscale.ListNodes()
		assert.NoError(c, err)
		assert.Len(c, nodes, 6)
		require.GreaterOrEqual(t, len(nodes), 3, "need at least 3 nodes to avoid panic")
		// After router 3 re-approval: Router 2 remains PRIMARY, Routers 1&3 are STANDBY
		// SubnetRoutes should only show routes for PRIMARY node (actively serving)
		requireNodeRouteCountWithCollect(c, nodes[0], 1, 1, 0) // Router 1: STANDBY (available, approved, but not serving)
		requireNodeRouteCountWithCollect(c, nodes[1], 1, 1, 1) // Router 2: PRIMARY (available, approved, and serving)
		requireNodeRouteCountWithCollect(c, nodes[2], 1, 1, 0) // Router 3: STANDBY (available, approved, but not serving)
	}, propagationTime, 200*time.Millisecond, "Waiting for route state after router 3 re-approval")

	// Validate primary routes table state after router 3 re-approval
	validatePrimaryRoutes(t, headscale, &routes.DebugRoutes{
		AvailableRoutes: map[types.NodeID][]netip.Prefix{
			types.NodeID(MustFindNode(subRouter1.Hostname(), nodes).GetId()): {pref},
			types.NodeID(MustFindNode(subRouter2.Hostname(), nodes).GetId()): {pref},
			types.NodeID(MustFindNode(subRouter3.Hostname(), nodes).GetId()): {pref},
		},
		PrimaryRoutes: map[string]types.NodeID{
			pref.String(): types.NodeID(MustFindNode(subRouter2.Hostname(), nodes).GetId()),
		},
	}, "Router 2 should remain primary after router 3 re-approval")

	checkFailureAndPrintRoutes(t, client)
}

// TestSubnetRouteACL verifies that Subnet routes are distributed
// as expected when ACLs are activated.
// It implements the issue from
// https://github.com/juanfont/headscale/issues/1604
func TestSubnetRouteACL(t *testing.T) {
	IntegrationSkip(t)

	user := "user4"

	spec := ScenarioSpec{
		NodesPerUser: 2,
		Users:        []string{user},
	}

	scenario, err := NewScenario(spec)

	require.NoErrorf(t, err, "failed to create scenario: %s", err)
	defer scenario.ShutdownAssertNoPanics(t)

	err = scenario.CreateHeadscaleEnv([]tsic.Option{
		tsic.WithAcceptRoutes(),
	}, hsic.WithTestName("rt-subnetacl"), hsic.WithACLPolicy(
		&policyv2.Policy{
			Groups: policyv2.Groups{
				policyv2.Group("group:admins"): []policyv2.Username{policyv2.Username(user + "@")},
			},
			ACLs: []policyv2.ACL{
				{
					Action:  "accept",
					Sources: []policyv2.Alias{groupp("group:admins")},
					Destinations: []policyv2.AliasWithPorts{
						aliasWithPorts(groupp("group:admins"), tailcfg.PortRangeAny),
					},
				},
				{
					Action:  "accept",
					Sources: []policyv2.Alias{groupp("group:admins")},
					Destinations: []policyv2.AliasWithPorts{
						aliasWithPorts(prefixp("10.33.0.0/16"), tailcfg.PortRangeAny),
					},
				},
			},
		},
	))
	requireNoErrHeadscaleEnv(t, err)

	allClients, err := scenario.ListTailscaleClients()
	requireNoErrListClients(t, err)

	err = scenario.WaitForTailscaleSync()
	requireNoErrSync(t, err)

	headscale, err := scenario.Headscale()
	requireNoErrGetHeadscale(t, err)

	expectedRoutes := map[string]string{
		"1": "10.33.0.0/16",
	}

	// Sort nodes by ID
	sort.SliceStable(allClients, func(i, j int) bool {
		statusI := allClients[i].MustStatus()
		statusJ := allClients[j].MustStatus()

		return statusI.Self.ID < statusJ.Self.ID
	})

	subRouter1 := allClients[0]

	client := allClients[1]

	for _, client := range allClients {
		assert.EventuallyWithT(t, func(c *assert.CollectT) {
			status, err := client.Status()
			assert.NoError(c, err)

			if route, ok := expectedRoutes[string(status.Self.ID)]; ok {
				command := []string{
					"tailscale",
					"set",
					"--advertise-routes=" + route,
				}
				_, _, err = client.Execute(command)
				assert.NoErrorf(c, err, "failed to advertise route: %s", err)
			}
		}, integrationutil.ScaledTimeout(5*time.Second), 200*time.Millisecond, "Configuring route advertisements")
	}

	err = scenario.WaitForTailscaleSync()
	requireNoErrSync(t, err)

	// Wait for route advertisements to propagate to the server
	var nodes []*v1.Node

	require.EventuallyWithT(t, func(c *assert.CollectT) {
		var err error

		nodes, err = headscale.ListNodes()
		assert.NoError(c, err)
		assert.Len(c, nodes, 2)

		// Find the node that should have the route by checking node IDs
		var (
			routeNode *v1.Node
			otherNode *v1.Node
		)

		for _, node := range nodes {
			nodeIDStr := strconv.FormatUint(node.GetId(), 10)
			if _, shouldHaveRoute := expectedRoutes[nodeIDStr]; shouldHaveRoute {
				routeNode = node
			} else {
				otherNode = node
			}
		}

		assert.NotNil(c, routeNode, "could not find node that should have route")
		assert.NotNil(c, otherNode, "could not find node that should not have route")

		// After NodeStore fix: routes are properly tracked in route manager
		// This test uses a policy with NO auto-approvers, so routes should be:
		// announced=1, approved=0, subnet=0 (routes announced but not approved)
		requireNodeRouteCountWithCollect(c, routeNode, 1, 0, 0)
		requireNodeRouteCountWithCollect(c, otherNode, 0, 0, 0)
	}, integrationutil.ScaledTimeout(10*time.Second), 100*time.Millisecond, "route advertisements should propagate to server")

	// Verify that no routes has been sent to the client,
	// they are not yet enabled.
	for _, client := range allClients {
		assert.EventuallyWithT(t, func(c *assert.CollectT) {
			status, err := client.Status()
			assert.NoError(c, err)

			for _, peerKey := range status.Peers() {
				peerStatus := status.Peer[peerKey]

				assert.Nil(c, peerStatus.PrimaryRoutes)
				requirePeerSubnetRoutesWithCollect(c, peerStatus, nil)
			}
		}, integrationutil.ScaledTimeout(5*time.Second), 200*time.Millisecond, "Verifying no routes are active before approval")
	}

	_, err = headscale.ApproveRoutes(
		1,
		[]netip.Prefix{netip.MustParsePrefix(expectedRoutes["1"])},
	)
	require.NoError(t, err)

	// Wait for route state changes to propagate to nodes
	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		nodes, err = headscale.ListNodes()
		assert.NoError(c, err)
		assert.Len(c, nodes, 2)

		requireNodeRouteCountWithCollect(c, nodes[0], 1, 1, 1)
		requireNodeRouteCountWithCollect(c, nodes[1], 0, 0, 0)
	}, integrationutil.ScaledTimeout(10*time.Second), 500*time.Millisecond, "route state changes should propagate to nodes")

	// Verify that the client has routes from the primary machine
	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		srs1, err := subRouter1.Status()
		assert.NoError(c, err)

		clientStatus, err := client.Status()
		assert.NoError(c, err)

		srs1PeerStatus := clientStatus.Peer[srs1.Self.PublicKey]

		assert.NotNil(c, srs1PeerStatus, "Router 1 peer should exist")

		if srs1PeerStatus == nil {
			return
		}

		requirePeerSubnetRoutesWithCollect(c, srs1PeerStatus, []netip.Prefix{netip.MustParsePrefix(expectedRoutes["1"])})
	}, integrationutil.ScaledTimeout(5*time.Second), 200*time.Millisecond, "Verifying client can see subnet routes from router")

	// Wait for packet filter updates to propagate to client netmap
	wantClientFilter := []filter.Match{
		{
			IPProto: views.SliceOf([]ipproto.Proto{
				ipproto.TCP, ipproto.UDP, ipproto.ICMPv4, ipproto.ICMPv6,
			}),
			Srcs: []netip.Prefix{
				netip.MustParsePrefix("100.64.0.1/32"),
				netip.MustParsePrefix("100.64.0.2/32"),
				netip.MustParsePrefix("fd7a:115c:a1e0::1/128"),
				netip.MustParsePrefix("fd7a:115c:a1e0::2/128"),
			},
			Dsts: []filter.NetPortRange{
				{
					Net:   netip.MustParsePrefix("100.64.0.2/32"),
					Ports: allPorts,
				},
				{
					Net:   netip.MustParsePrefix("fd7a:115c:a1e0::2/128"),
					Ports: allPorts,
				},
			},
			Caps: []filter.CapMatch{},
		},
	}

	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		clientNm, err := client.Netmap()
		assert.NoError(c, err)

		if diff := cmpdiff.Diff(wantClientFilter, clientNm.PacketFilter, util.ViewSliceIPProtoComparer, util.PrefixComparer); diff != "" {
			assert.Fail(c, fmt.Sprintf("Client (%s) filter, unexpected result (-want +got):\n%s", client.Hostname(), diff))
		}
	}, integrationutil.ScaledTimeout(10*time.Second), 200*time.Millisecond, "Waiting for client packet filter to update")

	// Wait for packet filter updates to propagate to subnet router netmap
	// The two ACL rules (group:admins -> group:admins:* and group:admins -> 10.33.0.0/16:*)
	// are merged into one filter rule since they share the same SrcIPs and IPProto.
	wantSubnetFilter := []filter.Match{
		{
			IPProto: views.SliceOf([]ipproto.Proto{
				ipproto.TCP, ipproto.UDP, ipproto.ICMPv4, ipproto.ICMPv6,
			}),
			Srcs: []netip.Prefix{
				netip.MustParsePrefix("100.64.0.1/32"),
				netip.MustParsePrefix("100.64.0.2/32"),
				netip.MustParsePrefix("fd7a:115c:a1e0::1/128"),
				netip.MustParsePrefix("fd7a:115c:a1e0::2/128"),
			},
			Dsts: []filter.NetPortRange{
				{
					Net:   netip.MustParsePrefix("100.64.0.1/32"),
					Ports: allPorts,
				},
				{
					Net:   netip.MustParsePrefix("fd7a:115c:a1e0::1/128"),
					Ports: allPorts,
				},
				{
					Net:   netip.MustParsePrefix("10.33.0.0/16"),
					Ports: allPorts,
				},
			},
			Caps: []filter.CapMatch{},
		},
	}

	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		subnetNm, err := subRouter1.Netmap()
		assert.NoError(c, err)

		if diff := cmpdiff.Diff(wantSubnetFilter, subnetNm.PacketFilter, util.ViewSliceIPProtoComparer, util.PrefixComparer); diff != "" {
			assert.Fail(c, fmt.Sprintf("Subnet (%s) filter, unexpected result (-want +got):\n%s", subRouter1.Hostname(), diff))
		}
	}, integrationutil.ScaledTimeout(10*time.Second), 200*time.Millisecond, "Waiting for subnet router packet filter to update")
}

// TestEnablingExitRoutes tests enabling exit routes for clients.
// Its more or less the same as TestEnablingRoutes, but with the --advertise-exit-node flag
// set during login instead of set.
func TestEnablingExitRoutes(t *testing.T) {
	IntegrationSkip(t)

	user := "user2" //nolint:goconst // test-specific value, not related to userToDelete constant

	spec := ScenarioSpec{
		NodesPerUser: 2,
		Users:        []string{user},
	}

	scenario, err := NewScenario(spec)

	require.NoErrorf(t, err, "failed to create scenario")
	defer scenario.ShutdownAssertNoPanics(t)

	err = scenario.CreateHeadscaleEnv([]tsic.Option{
		tsic.WithExtraLoginArgs([]string{"--advertise-exit-node"}),
	}, hsic.WithTestName("rt-exitroute"))
	requireNoErrHeadscaleEnv(t, err)

	allClients, err := scenario.ListTailscaleClients()
	requireNoErrListClients(t, err)

	err = scenario.WaitForTailscaleSync()
	requireNoErrSync(t, err)

	headscale, err := scenario.Headscale()
	requireNoErrGetHeadscale(t, err)

	err = scenario.WaitForTailscaleSync()
	requireNoErrSync(t, err)

	var nodes []*v1.Node

	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		var err error

		nodes, err = headscale.ListNodes()
		assert.NoError(c, err)
		assert.Len(c, nodes, 2)

		requireNodeRouteCountWithCollect(c, nodes[0], 2, 0, 0)
		requireNodeRouteCountWithCollect(c, nodes[1], 2, 0, 0)
	}, integrationutil.ScaledTimeout(10*time.Second), 200*time.Millisecond, "Waiting for route advertisements to propagate")

	// Verify that no routes has been sent to the client,
	// they are not yet enabled.
	for _, client := range allClients {
		assert.EventuallyWithT(t, func(c *assert.CollectT) {
			status, err := client.Status()
			assert.NoError(c, err)

			for _, peerKey := range status.Peers() {
				peerStatus := status.Peer[peerKey]

				assert.Nil(c, peerStatus.PrimaryRoutes)
			}
		}, integrationutil.ScaledTimeout(5*time.Second), 200*time.Millisecond, "Verifying no exit routes are active before approval")
	}

	// Enable all routes, but do v4 on one and v6 on other to ensure they
	// are both added since they are exit routes.
	_, err = headscale.ApproveRoutes(
		nodes[0].GetId(),
		[]netip.Prefix{tsaddr.AllIPv4()},
	)
	require.NoError(t, err)
	_, err = headscale.ApproveRoutes(
		nodes[1].GetId(),
		[]netip.Prefix{tsaddr.AllIPv6()},
	)
	require.NoError(t, err)

	// Wait for route state changes to propagate
	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		nodes, err = headscale.ListNodes()
		assert.NoError(c, err)
		assert.Len(c, nodes, 2)

		requireNodeRouteCountWithCollect(c, nodes[0], 2, 2, 2)
		requireNodeRouteCountWithCollect(c, nodes[1], 2, 2, 2)
	}, integrationutil.ScaledTimeout(10*time.Second), 500*time.Millisecond, "route state changes should propagate to both nodes")

	// Wait for route state changes to propagate to clients
	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		// Verify that the clients can see the new routes
		for _, client := range allClients {
			status, err := client.Status()
			assert.NoError(c, err)

			for _, peerKey := range status.Peers() {
				peerStatus := status.Peer[peerKey]

				assert.NotNil(c, peerStatus.AllowedIPs)

				if peerStatus.AllowedIPs != nil {
					assert.Len(c, peerStatus.AllowedIPs.AsSlice(), 4)
					assert.Contains(c, peerStatus.AllowedIPs.AsSlice(), tsaddr.AllIPv4())
					assert.Contains(c, peerStatus.AllowedIPs.AsSlice(), tsaddr.AllIPv6())
				}
			}
		}
	}, integrationutil.ScaledTimeout(10*time.Second), 500*time.Millisecond, "clients should see new routes")
}

// TestSubnetRouterMultiNetwork is an evolution of the subnet router test.
// This test will set up multiple docker networks and use two isolated tailscale
// clients and a service available in one of the networks to validate that a
// subnet router is working as expected.
func TestSubnetRouterMultiNetwork(t *testing.T) {
	IntegrationSkip(t)

	spec := ScenarioSpec{
		NodesPerUser: 1,
		Users:        []string{"user1", "user2"},
		Networks: map[string][]string{
			"usernet1": {"user1"},
			"usernet2": {"user2"},
		},
		ExtraService: map[string][]extraServiceFunc{
			"usernet1": {Webservice},
		},
	}

	scenario, err := NewScenario(spec)

	require.NoErrorf(t, err, "failed to create scenario: %s", err)
	defer scenario.ShutdownAssertNoPanics(t)

	err = scenario.CreateHeadscaleEnv([]tsic.Option{tsic.WithAcceptRoutes()},
		hsic.WithTestName("rt-multinet"),
	)
	requireNoErrHeadscaleEnv(t, err)

	allClients, err := scenario.ListTailscaleClients()
	requireNoErrListClients(t, err)

	err = scenario.WaitForTailscaleSync()
	requireNoErrSync(t, err)

	headscale, err := scenario.Headscale()
	requireNoErrGetHeadscale(t, err)
	assert.NotNil(t, headscale)

	pref, err := scenario.SubnetOfNetwork("usernet1")
	require.NoError(t, err)

	var user1c, user2c TailscaleClient

	for _, c := range allClients {
		s := c.MustStatus()
		if s.User[s.Self.UserID].LoginName == "user1@test.no" {
			user1c = c
		}

		if s.User[s.Self.UserID].LoginName == "user2@test.no" {
			user2c = c
		}
	}

	require.NotNil(t, user1c)
	require.NotNil(t, user2c)

	// Advertise the route for the dockersubnet of user1
	command := []string{
		"tailscale",
		"set",
		"--advertise-routes=" + pref.String(),
	}
	_, _, err = user1c.Execute(command)
	require.NoErrorf(t, err, "failed to advertise route: %s", err)

	var nodes []*v1.Node
	// Wait for route advertisements to propagate to NodeStore
	assert.EventuallyWithT(t, func(ct *assert.CollectT) {
		var err error

		nodes, err = headscale.ListNodes()
		assert.NoError(ct, err)
		assert.Len(ct, nodes, 2)
		requireNodeRouteCountWithCollect(ct, nodes[0], 1, 0, 0)
	}, integrationutil.ScaledTimeout(10*time.Second), 100*time.Millisecond, "route advertisements should propagate")

	// Verify that no routes has been sent to the client,
	// they are not yet enabled.
	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		status, err := user1c.Status()
		assert.NoError(c, err)

		for _, peerKey := range status.Peers() {
			peerStatus := status.Peer[peerKey]

			assert.Nil(c, peerStatus.PrimaryRoutes)
			requirePeerSubnetRoutesWithCollect(c, peerStatus, nil)
		}
	}, integrationutil.ScaledTimeout(5*time.Second), 200*time.Millisecond, "Verifying no routes are active before approval")

	// Enable route
	_, err = headscale.ApproveRoutes(
		nodes[0].GetId(),
		[]netip.Prefix{*pref},
	)
	require.NoError(t, err)

	// Wait for route state changes to propagate to nodes
	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		var err error

		nodes, err = headscale.ListNodes()
		assert.NoError(c, err)
		assert.Len(c, nodes, 2)
		requireNodeRouteCountWithCollect(c, nodes[0], 1, 1, 1)
	}, integrationutil.ScaledTimeout(10*time.Second), 500*time.Millisecond, "route state changes should propagate to nodes")

	// Verify that the routes have been sent to the client
	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		status, err := user2c.Status()
		assert.NoError(c, err)

		for _, peerKey := range status.Peers() {
			peerStatus := status.Peer[peerKey]

			if peerStatus.PrimaryRoutes != nil {
				assert.Contains(c, peerStatus.PrimaryRoutes.AsSlice(), *pref)
			}

			requirePeerSubnetRoutesWithCollect(c, peerStatus, []netip.Prefix{*pref})
		}
	}, integrationutil.ScaledTimeout(10*time.Second), 500*time.Millisecond, "routes should be visible to client")

	usernet1, err := scenario.Network("usernet1")
	require.NoError(t, err)

	services, err := scenario.Services("usernet1")
	require.NoError(t, err)
	require.Len(t, services, 1)

	web := services[0]
	webip := netip.MustParseAddr(web.GetIPInNetwork(usernet1))

	url := fmt.Sprintf("http://%s/etc/hostname", webip)
	t.Logf("url from %s to %s", user2c.Hostname(), url)

	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		result, err := user2c.Curl(url)
		assert.NoError(c, err)
		assert.Len(c, result, 13)
	}, integrationutil.ScaledTimeout(5*time.Second), 200*time.Millisecond, "Verifying client can reach webservice through subnet route")

	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		tr, err := user2c.Traceroute(webip)
		assert.NoError(c, err)

		ip, err := user1c.IPv4()
		if !assert.NoError(c, err, "failed to get IPv4 for user1c") {
			return
		}

		assertTracerouteViaIPWithCollect(c, tr, ip)
	}, integrationutil.ScaledTimeout(5*time.Second), 200*time.Millisecond, "Verifying traceroute goes through subnet router")
}

func TestSubnetRouterMultiNetworkExitNode(t *testing.T) {
	IntegrationSkip(t)

	spec := ScenarioSpec{
		NodesPerUser: 1,
		Users:        []string{"user1", "user2"},
		Networks: map[string][]string{
			"usernet1": {"user1"},
			"usernet2": {"user2"},
		},
		ExtraService: map[string][]extraServiceFunc{
			"usernet1": {Webservice},
		},
	}

	scenario, err := NewScenario(spec)

	require.NoErrorf(t, err, "failed to create scenario: %s", err)
	defer scenario.ShutdownAssertNoPanics(t)

	err = scenario.CreateHeadscaleEnv([]tsic.Option{},
		hsic.WithTestName("rt-multinetexit"),
	)
	requireNoErrHeadscaleEnv(t, err)

	allClients, err := scenario.ListTailscaleClients()
	requireNoErrListClients(t, err)

	err = scenario.WaitForTailscaleSync()
	requireNoErrSync(t, err)

	headscale, err := scenario.Headscale()
	requireNoErrGetHeadscale(t, err)
	assert.NotNil(t, headscale)

	var user1c, user2c TailscaleClient

	for _, c := range allClients {
		s := c.MustStatus()
		if s.User[s.Self.UserID].LoginName == "user1@test.no" {
			user1c = c
		}

		if s.User[s.Self.UserID].LoginName == "user2@test.no" {
			user2c = c
		}
	}

	require.NotNil(t, user1c)
	require.NotNil(t, user2c)

	// Advertise the exit nodes for the dockersubnet of user1
	command := []string{
		"tailscale",
		"set",
		"--advertise-exit-node",
	}
	_, _, err = user1c.Execute(command)
	require.NoErrorf(t, err, "failed to advertise route: %s", err)

	var nodes []*v1.Node
	// Wait for route advertisements to propagate to NodeStore
	assert.EventuallyWithT(t, func(ct *assert.CollectT) {
		var err error

		nodes, err = headscale.ListNodes()
		assert.NoError(ct, err)
		assert.Len(ct, nodes, 2)
		requireNodeRouteCountWithCollect(ct, nodes[0], 2, 0, 0)
	}, integrationutil.ScaledTimeout(10*time.Second), 100*time.Millisecond, "route advertisements should propagate")

	// Verify that no routes has been sent to the client,
	// they are not yet enabled.
	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		status, err := user1c.Status()
		assert.NoError(c, err)

		for _, peerKey := range status.Peers() {
			peerStatus := status.Peer[peerKey]

			assert.Nil(c, peerStatus.PrimaryRoutes)
			requirePeerSubnetRoutesWithCollect(c, peerStatus, nil)
		}
	}, integrationutil.ScaledTimeout(5*time.Second), 200*time.Millisecond, "Verifying no routes sent to client before approval")

	// Enable route
	_, err = headscale.ApproveRoutes(nodes[0].GetId(), []netip.Prefix{tsaddr.AllIPv4()})
	require.NoError(t, err)

	// Wait for route state changes to propagate to nodes
	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		nodes, err = headscale.ListNodes()
		assert.NoError(c, err)
		assert.Len(c, nodes, 2)
		requireNodeRouteCountWithCollect(c, nodes[0], 2, 2, 2)
	}, integrationutil.ScaledTimeout(10*time.Second), 500*time.Millisecond, "route state changes should propagate to nodes")

	// Verify that the routes have been sent to the client
	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		status, err := user2c.Status()
		assert.NoError(c, err)

		for _, peerKey := range status.Peers() {
			peerStatus := status.Peer[peerKey]

			requirePeerSubnetRoutesWithCollect(c, peerStatus, []netip.Prefix{tsaddr.AllIPv4(), tsaddr.AllIPv6()})
		}
	}, integrationutil.ScaledTimeout(10*time.Second), 500*time.Millisecond, "routes should be visible to client")

	// Tell user2c to use user1c as an exit node.
	command = []string{
		"tailscale",
		"set",
		"--exit-node",
		user1c.Hostname(),
	}
	_, _, err = user2c.Execute(command)
	require.NoErrorf(t, err, "failed to advertise route: %s", err)

	usernet1, err := scenario.Network("usernet1")
	require.NoError(t, err)

	services, err := scenario.Services("usernet1")
	require.NoError(t, err)
	require.Len(t, services, 1)

	web := services[0]
	webip := netip.MustParseAddr(web.GetIPInNetwork(usernet1))

	// We can't mess to much with ip forwarding in containers so
	// we settle for a simple ping here.
	// Direct is false since we use internal DERP which means we
	// can't discover a direct path between docker networks.
	err = user2c.Ping(webip.String(),
		tsic.WithPingUntilDirect(false),
		tsic.WithPingCount(1),
		tsic.WithPingTimeout(7*time.Second),
	)
	require.NoError(t, err)
}

func MustFindNode(hostname string, nodes []*v1.Node) *v1.Node {
	for _, node := range nodes {
		if node.GetName() == hostname {
			return node
		}
	}

	panic("node not found")
}

// TestAutoApproveMultiNetwork tests auto approving of routes
// by setting up two networks where network1 has three subnet
// routers:
// - routerUsernet1: advertising the docker network
// - routerSubRoute: advertising a subroute, a /24 inside a auto approved /16
// - routeExitNode: advertising an exit node
//
// Each router is tested step by step through the following scenarios
//   - Policy is set to auto approve the nodes route
//   - Node advertises route and it is verified that it is auto approved and sent to nodes
//   - Policy is changed to _not_ auto approve the route
//   - Verify that peers can still see the node
//   - Disable route, making it unavailable
//   - Verify that peers can no longer use node
//   - Policy is changed back to auto approve route, check that routes already existing is approved.
//   - Verify that routes can now be seen by peers.
//
//nolint:gocyclo // complex multi-network auto-approve test scenario
func TestAutoApproveMultiNetwork(t *testing.T) {
	IntegrationSkip(t)

	// Timeout for EventuallyWithT assertions.
	// Set generously to account for CI infrastructure variability.
	assertTimeout := integrationutil.ScaledTimeout(60 * time.Second)

	bigRoute := netip.MustParsePrefix("10.42.0.0/16")
	subRoute := netip.MustParsePrefix("10.42.7.0/24")
	notApprovedRoute := netip.MustParsePrefix("192.168.0.0/24")

	tests := []struct {
		name     string
		pol      *policyv2.Policy
		approver string
		spec     ScenarioSpec
		withURL  bool
	}{
		{
			name: "authkey-tag",
			pol: &policyv2.Policy{
				ACLs: []policyv2.ACL{
					{
						Action:  "accept",
						Sources: []policyv2.Alias{wildcard()},
						Destinations: []policyv2.AliasWithPorts{
							aliasWithPorts(wildcard(), tailcfg.PortRangeAny),
						},
					},
				},
				TagOwners: policyv2.TagOwners{
					policyv2.Tag("tag:approve"): policyv2.Owners{usernameOwner("user1@")},
				},
				AutoApprovers: policyv2.AutoApproverPolicy{
					Routes: map[netip.Prefix]policyv2.AutoApprovers{
						bigRoute: {tagApprover("tag:approve")},
					},
					ExitNode: policyv2.AutoApprovers{tagApprover("tag:approve")},
				},
			},
			approver: "tag:approve",
			spec: ScenarioSpec{
				NodesPerUser: 3,
				Users:        []string{"user1", "user2"},
				Networks: map[string][]string{
					"usernet1": {"user1"},
					"usernet2": {"user2"},
				},
				ExtraService: map[string][]extraServiceFunc{
					"usernet1": {Webservice},
				},
				// We build the head image with curl and traceroute, so only use
				// that for this test.
				Versions: []string{"head"},
			},
		},
		{
			name: "authkey-user",
			pol: &policyv2.Policy{
				ACLs: []policyv2.ACL{
					{
						Action:  "accept",
						Sources: []policyv2.Alias{wildcard()},
						Destinations: []policyv2.AliasWithPorts{
							aliasWithPorts(wildcard(), tailcfg.PortRangeAny),
						},
					},
				},
				AutoApprovers: policyv2.AutoApproverPolicy{
					Routes: map[netip.Prefix]policyv2.AutoApprovers{
						bigRoute: {usernameApprover("user1@")},
					},
					ExitNode: policyv2.AutoApprovers{usernameApprover("user1@")},
				},
			},
			approver: "user1@",
			spec: ScenarioSpec{
				NodesPerUser: 3,
				Users:        []string{"user1", "user2"},
				Networks: map[string][]string{
					"usernet1": {"user1"},
					"usernet2": {"user2"},
				},
				ExtraService: map[string][]extraServiceFunc{
					"usernet1": {Webservice},
				},
				// We build the head image with curl and traceroute, so only use
				// that for this test.
				Versions: []string{"head"},
			},
		},
		{
			name: "authkey-group",
			pol: &policyv2.Policy{
				ACLs: []policyv2.ACL{
					{
						Action:  "accept",
						Sources: []policyv2.Alias{wildcard()},
						Destinations: []policyv2.AliasWithPorts{
							aliasWithPorts(wildcard(), tailcfg.PortRangeAny),
						},
					},
				},
				Groups: policyv2.Groups{
					policyv2.Group("group:approve"): []policyv2.Username{policyv2.Username("user1@")},
				},
				AutoApprovers: policyv2.AutoApproverPolicy{
					Routes: map[netip.Prefix]policyv2.AutoApprovers{
						bigRoute: {groupApprover("group:approve")},
					},
					ExitNode: policyv2.AutoApprovers{groupApprover("group:approve")},
				},
			},
			approver: "group:approve",
			spec: ScenarioSpec{
				NodesPerUser: 3,
				Users:        []string{"user1", "user2"},
				Networks: map[string][]string{
					"usernet1": {"user1"},
					"usernet2": {"user2"},
				},
				ExtraService: map[string][]extraServiceFunc{
					"usernet1": {Webservice},
				},
				// We build the head image with curl and traceroute, so only use
				// that for this test.
				Versions: []string{"head"},
			},
		},
		{
			name: "webauth-user",
			pol: &policyv2.Policy{
				ACLs: []policyv2.ACL{
					{
						Action:  "accept",
						Sources: []policyv2.Alias{wildcard()},
						Destinations: []policyv2.AliasWithPorts{
							aliasWithPorts(wildcard(), tailcfg.PortRangeAny),
						},
					},
				},
				AutoApprovers: policyv2.AutoApproverPolicy{
					Routes: map[netip.Prefix]policyv2.AutoApprovers{
						bigRoute: {usernameApprover("user1@")},
					},
					ExitNode: policyv2.AutoApprovers{usernameApprover("user1@")},
				},
			},
			approver: "user1@",
			spec: ScenarioSpec{
				NodesPerUser: 3,
				Users:        []string{"user1", "user2"},
				Networks: map[string][]string{
					"usernet1": {"user1"},
					"usernet2": {"user2"},
				},
				ExtraService: map[string][]extraServiceFunc{
					"usernet1": {Webservice},
				},
				// We build the head image with curl and traceroute, so only use
				// that for this test.
				Versions: []string{"head"},
			},
			withURL: true,
		},
		{
			name: "webauth-tag",
			pol: &policyv2.Policy{
				ACLs: []policyv2.ACL{
					{
						Action:  "accept",
						Sources: []policyv2.Alias{wildcard()},
						Destinations: []policyv2.AliasWithPorts{
							aliasWithPorts(wildcard(), tailcfg.PortRangeAny),
						},
					},
				},
				TagOwners: policyv2.TagOwners{
					policyv2.Tag("tag:approve"): policyv2.Owners{usernameOwner("user1@")},
				},
				AutoApprovers: policyv2.AutoApproverPolicy{
					Routes: map[netip.Prefix]policyv2.AutoApprovers{
						bigRoute: {tagApprover("tag:approve")},
					},
					ExitNode: policyv2.AutoApprovers{tagApprover("tag:approve")},
				},
			},
			approver: "tag:approve",
			spec: ScenarioSpec{
				NodesPerUser: 3,
				Users:        []string{"user1", "user2"},
				Networks: map[string][]string{
					"usernet1": {"user1"},
					"usernet2": {"user2"},
				},
				ExtraService: map[string][]extraServiceFunc{
					"usernet1": {Webservice},
				},
				// We build the head image with curl and traceroute, so only use
				// that for this test.
				Versions: []string{"head"},
			},
			withURL: true,
		},
		{
			name: "webauth-group",
			pol: &policyv2.Policy{
				ACLs: []policyv2.ACL{
					{
						Action:  "accept",
						Sources: []policyv2.Alias{wildcard()},
						Destinations: []policyv2.AliasWithPorts{
							aliasWithPorts(wildcard(), tailcfg.PortRangeAny),
						},
					},
				},
				Groups: policyv2.Groups{
					policyv2.Group("group:approve"): []policyv2.Username{policyv2.Username("user1@")},
				},
				AutoApprovers: policyv2.AutoApproverPolicy{
					Routes: map[netip.Prefix]policyv2.AutoApprovers{
						bigRoute: {groupApprover("group:approve")},
					},
					ExitNode: policyv2.AutoApprovers{groupApprover("group:approve")},
				},
			},
			approver: "group:approve",
			spec: ScenarioSpec{
				NodesPerUser: 3,
				Users:        []string{"user1", "user2"},
				Networks: map[string][]string{
					"usernet1": {"user1"},
					"usernet2": {"user2"},
				},
				ExtraService: map[string][]extraServiceFunc{
					"usernet1": {Webservice},
				},
				// We build the head image with curl and traceroute, so only use
				// that for this test.
				Versions: []string{"head"},
			},
			withURL: true,
		},
	}

	for _, tt := range tests {
		for _, polMode := range []types.PolicyMode{types.PolicyModeDB, types.PolicyModeFile} {
			for _, advertiseDuringUp := range []bool{false, true} {
				name := fmt.Sprintf("%s-advertiseduringup-%t-pol-%s", tt.name, advertiseDuringUp, polMode)
				t.Run(name, func(t *testing.T) {
					// Create a deep copy of the policy to avoid mutating the shared test case.
					// Each subtest modifies AutoApprovers.Routes (add then delete), so we need
					// an isolated copy to prevent state leakage between sequential test runs.
					pol := &policyv2.Policy{
						ACLs:      slices.Clone(tt.pol.ACLs),
						Groups:    maps.Clone(tt.pol.Groups),
						TagOwners: maps.Clone(tt.pol.TagOwners),
						AutoApprovers: policyv2.AutoApproverPolicy{
							ExitNode: slices.Clone(tt.pol.AutoApprovers.ExitNode),
							Routes:   maps.Clone(tt.pol.AutoApprovers.Routes),
						},
					}

					scenario, err := NewScenario(tt.spec)

					require.NoErrorf(t, err, "failed to create scenario: %s", err)
					defer scenario.ShutdownAssertNoPanics(t)

					var nodes []*v1.Node

					opts := []hsic.Option{
						hsic.WithTestName("autoapprovemulti"),
						hsic.WithACLPolicy(pol),
						hsic.WithPolicyMode(polMode), // test iterates over file and DB policy modes
					}

					tsOpts := []tsic.Option{
						tsic.WithAcceptRoutes(),
					}

					route, err := scenario.SubnetOfNetwork("usernet1")
					require.NoError(t, err)

					// For tag-based approvers, nodes must be tagged with that tag
					// (tags-as-identity model: tagged nodes are identified by their tags)
					var (
						preAuthKeyTags []string
						webauthTagUser string
					)

					if strings.HasPrefix(tt.approver, "tag:") {
						preAuthKeyTags = []string{tt.approver}
						if tt.withURL {
							// For webauth, only user1 can request tags (per tagOwners policy)
							webauthTagUser = "user1" //nolint:goconst // test value, not a constant
						}
					}

					err = scenario.createHeadscaleEnvWithTags(tt.withURL, tsOpts, preAuthKeyTags, webauthTagUser,
						opts...,
					)
					requireNoErrHeadscaleEnv(t, err)

					allClients, err := scenario.ListTailscaleClients()
					requireNoErrListClients(t, err)

					err = scenario.WaitForTailscaleSync()
					requireNoErrSync(t, err)

					services, err := scenario.Services("usernet1")
					require.NoError(t, err)
					require.Len(t, services, 1)

					usernet1, err := scenario.Network("usernet1")
					require.NoError(t, err)

					headscale, err := scenario.Headscale()
					requireNoErrGetHeadscale(t, err)
					assert.NotNil(t, headscale)

					// Add the Docker network route to the auto-approvers
					// Keep existing auto-approvers (like bigRoute) in place
					var approvers policyv2.AutoApprovers

					switch {
					case strings.HasPrefix(tt.approver, "tag:"):
						approvers = append(approvers, tagApprover(tt.approver))
					case strings.HasPrefix(tt.approver, "group:"):
						approvers = append(approvers, groupApprover(tt.approver))
					default:
						approvers = append(approvers, usernameApprover(tt.approver))
					}
					// pol.AutoApprovers.Routes is already initialized in the deep copy above
					prefix := *route
					pol.AutoApprovers.Routes[prefix] = approvers
					err = headscale.SetPolicy(pol)
					require.NoError(t, err)

					if advertiseDuringUp {
						tsOpts = append(tsOpts,
							tsic.WithExtraLoginArgs([]string{"--advertise-routes=" + route.String()}),
						)
					}

					// For webauth with tag approver, the node needs to advertise the tag during registration
					// (tags-as-identity model: webauth nodes can use --advertise-tags if authorized by tagOwners)
					if tt.withURL && strings.HasPrefix(tt.approver, "tag:") {
						tsOpts = append(tsOpts, tsic.WithTags([]string{tt.approver}))
					}

					tsOpts = append(tsOpts, tsic.WithNetwork(usernet1))

					// This whole dance is to add a node _after_ all the other nodes
					// with an additional tsOpt which advertises the route as part
					// of the `tailscale up` command. If we do this as part of the
					// scenario creation, it will be added to all nodes and turn
					// into a HA node, which isn't something we are testing here.
					routerUsernet1, err := scenario.CreateTailscaleNode("head", tsOpts...)
					require.NoError(t, err)

					defer func() {
						_, _, err := routerUsernet1.Shutdown()
						require.NoError(t, err)
					}()

					if tt.withURL {
						u, err := routerUsernet1.LoginWithURL(headscale.GetEndpoint())
						require.NoError(t, err)

						body, err := doLoginURL(routerUsernet1.Hostname(), u)
						require.NoError(t, err)

						err = scenario.runHeadscaleRegister("user1", body)
						require.NoError(t, err)

						// Wait for the client to sync with the server after webauth registration.
						// Unlike authkey login which blocks until complete, webauth registration
						// happens on the server side and the client needs time to receive the network map.
						err = routerUsernet1.WaitForRunning(integrationutil.PeerSyncTimeout())
						require.NoError(t, err, "webauth client failed to reach Running state")
					} else {
						userMap, err := headscale.MapUsers()
						require.NoError(t, err)

						// If the approver is a tag, create a tagged PreAuthKey
						// (tags-as-identity model: tags come from PreAuthKey, not --advertise-tags)
						var pak *v1.PreAuthKey
						if strings.HasPrefix(tt.approver, "tag:") {
							pak, err = scenario.CreatePreAuthKeyWithTags(userMap["user1"].GetId(), false, false, []string{tt.approver})
						} else {
							pak, err = scenario.CreatePreAuthKey(userMap["user1"].GetId(), false, false)
						}

						require.NoError(t, err)

						err = routerUsernet1.Login(headscale.GetEndpoint(), pak.GetKey())
						require.NoError(t, err)
					}
					// extra creation end.

					// Wait for the node to be fully running before getting its ID
					// This is especially important for webauth flow where login is asynchronous
					err = routerUsernet1.WaitForRunning(integrationutil.ScaledTimeout(30 * time.Second))
					require.NoError(t, err)

					// Wait for bidirectional peer synchronization.
					// Both the router and all existing clients must see each other.
					// This is critical for connectivity - without this, the WireGuard
					// tunnels may not be established despite peers appearing in netmaps.

					// Router waits for all existing clients
					err = routerUsernet1.WaitForPeers(len(allClients), integrationutil.PeerSyncTimeout(), integrationutil.PeerSyncRetryInterval())
					require.NoError(t, err, "router failed to see all peers")

					// All clients wait for the router (they should see 6 peers including the router)
					for _, existingClient := range allClients {
						err = existingClient.WaitForPeers(len(allClients), integrationutil.PeerSyncTimeout(), integrationutil.PeerSyncRetryInterval())
						require.NoErrorf(t, err, "client %s failed to see all peers including router", existingClient.Hostname())
					}

					routerUsernet1ID := routerUsernet1.MustID()

					web := services[0]
					webip := netip.MustParseAddr(web.GetIPInNetwork(usernet1))
					weburl := fmt.Sprintf("http://%s/etc/hostname", webip)
					t.Logf("webservice: %s, %s", webip.String(), weburl)

					// Sort nodes by ID
					sort.SliceStable(allClients, func(i, j int) bool {
						statusI := allClients[i].MustStatus()
						statusJ := allClients[j].MustStatus()

						return statusI.Self.ID < statusJ.Self.ID
					})

					// This is ok because the scenario makes users in order, so the three first
					// nodes, which are subnet routes, will be created first, and the last user
					// will be created with the second.
					routerSubRoute := allClients[1]
					routerExitNode := allClients[2]

					client := allClients[3]

					if !advertiseDuringUp {
						// Advertise the route for the dockersubnet of user1
						command := []string{
							"tailscale",
							"set",
							"--advertise-routes=" + route.String(),
						}
						_, _, err = routerUsernet1.Execute(command)
						require.NoErrorf(t, err, "failed to advertise route: %s", err)
					}

					// Wait for route state changes to propagate.
					// Use a longer timeout (30s) to account for CI infrastructure variability -
					// when advertiseDuringUp=true, routes are sent during registration and may
					// take longer to propagate through the server's auto-approval logic in slow
					// environments.
					assert.EventuallyWithT(t, func(c *assert.CollectT) {
						// These route should auto approve, so the node is expected to have a route
						// for all counts.
						nodes, err := headscale.ListNodes()
						assert.NoError(c, err)

						routerNode := MustFindNode(routerUsernet1.Hostname(), nodes)
						t.Logf("Initial auto-approval check - Router node %s: announced=%v, approved=%v, subnet=%v",
							routerNode.GetName(),
							routerNode.GetAvailableRoutes(),
							routerNode.GetApprovedRoutes(),
							routerNode.GetSubnetRoutes())

						requireNodeRouteCountWithCollect(c, routerNode, 1, 1, 1)
					}, assertTimeout, 500*time.Millisecond, "Initial route auto-approval: Route should be approved via policy")

					// Verify that the routes have been sent to the client.
					assert.EventuallyWithT(t, func(c *assert.CollectT) {
						status, err := client.Status()
						assert.NoError(c, err)

						// Debug output to understand peer visibility
						t.Logf("Client %s sees %d peers", client.Hostname(), len(status.Peers()))

						routerPeerFound := false

						for _, peerKey := range status.Peers() {
							peerStatus := status.Peer[peerKey]

							if peerStatus.ID == routerUsernet1ID.StableID() {
								routerPeerFound = true

								t.Logf("Client sees router peer %s (ID=%s): AllowedIPs=%v, PrimaryRoutes=%v",
									peerStatus.HostName,
									peerStatus.ID,
									peerStatus.AllowedIPs,
									peerStatus.PrimaryRoutes)

								assert.NotNil(c, peerStatus.PrimaryRoutes)

								if peerStatus.PrimaryRoutes != nil {
									assert.Contains(c, peerStatus.PrimaryRoutes.AsSlice(), *route)
								}

								requirePeerSubnetRoutesWithCollect(c, peerStatus, []netip.Prefix{*route})
							} else {
								requirePeerSubnetRoutesWithCollect(c, peerStatus, nil)
							}
						}

						assert.True(c, routerPeerFound, "Client should see the router peer")
					}, assertTimeout, 200*time.Millisecond, "Verifying routes sent to client after auto-approval")

					// Verify WireGuard tunnel connectivity to the router before testing route.
					// The client may have the route in its netmap but the actual tunnel may not
					// be established yet, especially in CI environments with higher latency.
					routerIPv4, err := routerUsernet1.IPv4()
					require.NoError(t, err, "failed to get router IPv4")
					assert.EventuallyWithT(t, func(c *assert.CollectT) {
						err := client.Ping(
							routerIPv4.String(),
							tsic.WithPingUntilDirect(false), // DERP relay is fine
							tsic.WithPingCount(1),
							tsic.WithPingTimeout(5*time.Second),
						)
						assert.NoError(c, err, "ping to router should succeed")
					}, assertTimeout, 200*time.Millisecond, "Verifying WireGuard tunnel to router is established")

					url := fmt.Sprintf("http://%s/etc/hostname", webip)
					t.Logf("url from %s to %s", client.Hostname(), url)

					assert.EventuallyWithT(t, func(c *assert.CollectT) {
						result, err := client.Curl(url)
						assert.NoError(c, err)
						assert.Len(c, result, 13)
					}, assertTimeout, 200*time.Millisecond, "Verifying client can reach webservice through auto-approved route")

					assert.EventuallyWithT(t, func(c *assert.CollectT) {
						tr, err := client.Traceroute(webip)
						assert.NoError(c, err)

						ip, err := routerUsernet1.IPv4()
						if !assert.NoError(c, err, "failed to get IPv4 for routerUsernet1") {
							return
						}

						assertTracerouteViaIPWithCollect(c, tr, ip)
					}, assertTimeout, 200*time.Millisecond, "Verifying traceroute goes through auto-approved router")

					// Remove the auto approval from the policy, any routes already enabled should be allowed.
					prefix = *route
					delete(pol.AutoApprovers.Routes, prefix)
					err = headscale.SetPolicy(pol)
					require.NoError(t, err)
					t.Logf("Policy updated: removed auto-approver for route %s", prefix)

					// Wait for route state changes to propagate
					assert.EventuallyWithT(t, func(c *assert.CollectT) {
						// Routes already approved should remain approved even after policy change
						nodes, err = headscale.ListNodes()
						assert.NoError(c, err)

						routerNode := MustFindNode(routerUsernet1.Hostname(), nodes)
						t.Logf("After policy removal - Router node %s: announced=%v, approved=%v, subnet=%v",
							routerNode.GetName(),
							routerNode.GetAvailableRoutes(),
							routerNode.GetApprovedRoutes(),
							routerNode.GetSubnetRoutes())

						requireNodeRouteCountWithCollect(c, routerNode, 1, 1, 1)
					}, assertTimeout, 500*time.Millisecond, "Routes should remain approved after auto-approver removal")

					// Verify that the routes have been sent to the client.
					assert.EventuallyWithT(t, func(c *assert.CollectT) {
						status, err := client.Status()
						assert.NoError(c, err)

						for _, peerKey := range status.Peers() {
							peerStatus := status.Peer[peerKey]

							if peerStatus.ID == routerUsernet1ID.StableID() {
								assert.NotNil(c, peerStatus.PrimaryRoutes)

								if peerStatus.PrimaryRoutes != nil {
									assert.Contains(c, peerStatus.PrimaryRoutes.AsSlice(), *route)
								}

								requirePeerSubnetRoutesWithCollect(c, peerStatus, []netip.Prefix{*route})
							} else {
								requirePeerSubnetRoutesWithCollect(c, peerStatus, nil)
							}
						}
					}, assertTimeout, 200*time.Millisecond, "Verifying routes remain after policy change")

					url = fmt.Sprintf("http://%s/etc/hostname", webip)
					t.Logf("url from %s to %s", client.Hostname(), url)

					assert.EventuallyWithT(t, func(c *assert.CollectT) {
						result, err := client.Curl(url)
						assert.NoError(c, err)
						assert.Len(c, result, 13)
					}, assertTimeout, 200*time.Millisecond, "Verifying client can still reach webservice after policy change")

					assert.EventuallyWithT(t, func(c *assert.CollectT) {
						tr, err := client.Traceroute(webip)
						assert.NoError(c, err)

						ip, err := routerUsernet1.IPv4()
						if !assert.NoError(c, err, "failed to get IPv4 for routerUsernet1") {
							return
						}

						assertTracerouteViaIPWithCollect(c, tr, ip)
					}, assertTimeout, 200*time.Millisecond, "Verifying traceroute still goes through router after policy change")

					// Disable the route, making it unavailable since it is no longer auto-approved
					_, err = headscale.ApproveRoutes(
						MustFindNode(routerUsernet1.Hostname(), nodes).GetId(),
						[]netip.Prefix{},
					)
					require.NoError(t, err)

					// Wait for route state changes to propagate
					assert.EventuallyWithT(t, func(c *assert.CollectT) {
						// These route should auto approve, so the node is expected to have a route
						// for all counts.
						nodes, err = headscale.ListNodes()
						assert.NoError(c, err)
						requireNodeRouteCountWithCollect(c, MustFindNode(routerUsernet1.Hostname(), nodes), 1, 0, 0)
					}, assertTimeout, 500*time.Millisecond, "route state changes should propagate")

					// Verify that the routes have been sent to the client.
					assert.EventuallyWithT(t, func(c *assert.CollectT) {
						status, err := client.Status()
						assert.NoError(c, err)

						for _, peerKey := range status.Peers() {
							peerStatus := status.Peer[peerKey]
							requirePeerSubnetRoutesWithCollect(c, peerStatus, nil)
						}
					}, assertTimeout, 200*time.Millisecond, "Verifying routes disabled after route removal")

					// Add the route back to the auto approver in the policy, the route should
					// now become available again.
					var newApprovers policyv2.AutoApprovers

					switch {
					case strings.HasPrefix(tt.approver, "tag:"):
						newApprovers = append(newApprovers, tagApprover(tt.approver))
					case strings.HasPrefix(tt.approver, "group:"):
						newApprovers = append(newApprovers, groupApprover(tt.approver))
					default:
						newApprovers = append(newApprovers, usernameApprover(tt.approver))
					}
					// pol.AutoApprovers.Routes is already initialized in the deep copy above
					prefix = *route
					pol.AutoApprovers.Routes[prefix] = newApprovers
					err = headscale.SetPolicy(pol)
					require.NoError(t, err)

					// Wait for route state changes to propagate
					assert.EventuallyWithT(t, func(c *assert.CollectT) {
						// These route should auto approve, so the node is expected to have a route
						// for all counts.
						nodes, err = headscale.ListNodes()
						assert.NoError(c, err)
						requireNodeRouteCountWithCollect(c, MustFindNode(routerUsernet1.Hostname(), nodes), 1, 1, 1)
					}, assertTimeout, 500*time.Millisecond, "route state changes should propagate")

					// Verify that the routes have been sent to the client.
					assert.EventuallyWithT(t, func(c *assert.CollectT) {
						status, err := client.Status()
						assert.NoError(c, err)

						for _, peerKey := range status.Peers() {
							peerStatus := status.Peer[peerKey]

							if peerStatus.ID == routerUsernet1ID.StableID() {
								assert.NotNil(c, peerStatus.PrimaryRoutes)

								if peerStatus.PrimaryRoutes != nil {
									assert.Contains(c, peerStatus.PrimaryRoutes.AsSlice(), *route)
								}

								requirePeerSubnetRoutesWithCollect(c, peerStatus, []netip.Prefix{*route})
							} else {
								requirePeerSubnetRoutesWithCollect(c, peerStatus, nil)
							}
						}
					}, assertTimeout, 200*time.Millisecond, "Verifying routes re-enabled after policy re-approval")

					url = fmt.Sprintf("http://%s/etc/hostname", webip)
					t.Logf("url from %s to %s", client.Hostname(), url)

					assert.EventuallyWithT(t, func(c *assert.CollectT) {
						result, err := client.Curl(url)
						assert.NoError(c, err)
						assert.Len(c, result, 13)
					}, assertTimeout, 200*time.Millisecond, "Verifying client can reach webservice after route re-approval")

					assert.EventuallyWithT(t, func(c *assert.CollectT) {
						tr, err := client.Traceroute(webip)
						assert.NoError(c, err)

						ip, err := routerUsernet1.IPv4()
						if !assert.NoError(c, err, "failed to get IPv4 for routerUsernet1") {
							return
						}

						assertTracerouteViaIPWithCollect(c, tr, ip)
					}, assertTimeout, 200*time.Millisecond, "Verifying traceroute goes through router after re-approval")

					// Advertise and validate a subnet of an auto approved route, /24 inside the
					// auto approved /16.
					command := []string{
						"tailscale",
						"set",
						"--advertise-routes=" + subRoute.String(),
					}
					_, _, err = routerSubRoute.Execute(command)
					require.NoErrorf(t, err, "failed to advertise route: %s", err)

					// Wait for route state changes to propagate
					assert.EventuallyWithT(t, func(c *assert.CollectT) {
						// These route should auto approve, so the node is expected to have a route
						// for all counts.
						nodes, err = headscale.ListNodes()
						assert.NoError(c, err)
						requireNodeRouteCountWithCollect(c, MustFindNode(routerUsernet1.Hostname(), nodes), 1, 1, 1)
						requireNodeRouteCountWithCollect(c, nodes[1], 1, 1, 1)
					}, assertTimeout, 500*time.Millisecond, "route state changes should propagate")

					// Verify that the routes have been sent to the client.
					assert.EventuallyWithT(t, func(c *assert.CollectT) {
						status, err := client.Status()
						assert.NoError(c, err)

						for _, peerKey := range status.Peers() {
							peerStatus := status.Peer[peerKey]

							if peerStatus.ID == routerUsernet1ID.StableID() {
								if peerStatus.PrimaryRoutes != nil {
									assert.Contains(c, peerStatus.PrimaryRoutes.AsSlice(), *route)
								}

								requirePeerSubnetRoutesWithCollect(c, peerStatus, []netip.Prefix{*route})
							} else if peerStatus.ID == "2" {
								if peerStatus.PrimaryRoutes != nil {
									assert.Contains(c, peerStatus.PrimaryRoutes.AsSlice(), subRoute)
								}

								requirePeerSubnetRoutesWithCollect(c, peerStatus, []netip.Prefix{subRoute})
							} else {
								requirePeerSubnetRoutesWithCollect(c, peerStatus, nil)
							}
						}
					}, assertTimeout, 200*time.Millisecond, "Verifying sub-route propagated to client")

					// Advertise a not approved route will not end up anywhere
					command = []string{
						"tailscale",
						"set",
						"--advertise-routes=" + notApprovedRoute.String(),
					}
					_, _, err = routerSubRoute.Execute(command)
					require.NoErrorf(t, err, "failed to advertise route: %s", err)

					// Wait for route state changes to propagate
					assert.EventuallyWithT(t, func(c *assert.CollectT) {
						// These route should auto approve, so the node is expected to have a route
						// for all counts.
						nodes, err = headscale.ListNodes()
						assert.NoError(c, err)
						requireNodeRouteCountWithCollect(c, MustFindNode(routerUsernet1.Hostname(), nodes), 1, 1, 1)
						requireNodeRouteCountWithCollect(c, nodes[1], 1, 1, 0)
						requireNodeRouteCountWithCollect(c, nodes[2], 0, 0, 0)
					}, assertTimeout, 500*time.Millisecond, "route state changes should propagate")

					// Verify that the routes have been sent to the client.
					assert.EventuallyWithT(t, func(c *assert.CollectT) {
						status, err := client.Status()
						assert.NoError(c, err)

						for _, peerKey := range status.Peers() {
							peerStatus := status.Peer[peerKey]

							if peerStatus.ID == routerUsernet1ID.StableID() {
								assert.NotNil(c, peerStatus.PrimaryRoutes)

								if peerStatus.PrimaryRoutes != nil {
									assert.Contains(c, peerStatus.PrimaryRoutes.AsSlice(), *route)
								}

								requirePeerSubnetRoutesWithCollect(c, peerStatus, []netip.Prefix{*route})
							} else {
								requirePeerSubnetRoutesWithCollect(c, peerStatus, nil)
							}
						}
					}, assertTimeout, 200*time.Millisecond, "Verifying unapproved route not propagated")

					// Exit routes are also automatically approved
					command = []string{
						"tailscale",
						"set",
						"--advertise-exit-node",
					}
					_, _, err = routerExitNode.Execute(command)
					require.NoErrorf(t, err, "failed to advertise route: %s", err)

					// Wait for route state changes to propagate
					assert.EventuallyWithT(t, func(c *assert.CollectT) {
						nodes, err = headscale.ListNodes()
						assert.NoError(c, err)
						requireNodeRouteCountWithCollect(c, MustFindNode(routerUsernet1.Hostname(), nodes), 1, 1, 1)
						requireNodeRouteCountWithCollect(c, nodes[1], 1, 1, 0)
						requireNodeRouteCountWithCollect(c, nodes[2], 2, 2, 2)
					}, assertTimeout, 500*time.Millisecond, "route state changes should propagate")

					// Verify that the routes have been sent to the client.
					assert.EventuallyWithT(t, func(c *assert.CollectT) {
						status, err := client.Status()
						assert.NoError(c, err)

						for _, peerKey := range status.Peers() {
							peerStatus := status.Peer[peerKey]

							if peerStatus.ID == routerUsernet1ID.StableID() {
								if peerStatus.PrimaryRoutes != nil {
									assert.Contains(c, peerStatus.PrimaryRoutes.AsSlice(), *route)
								}

								requirePeerSubnetRoutesWithCollect(c, peerStatus, []netip.Prefix{*route})
							} else if peerStatus.ID == "3" {
								requirePeerSubnetRoutesWithCollect(c, peerStatus, []netip.Prefix{tsaddr.AllIPv4(), tsaddr.AllIPv6()})
							} else {
								requirePeerSubnetRoutesWithCollect(c, peerStatus, nil)
							}
						}
					}, assertTimeout, 200*time.Millisecond, "Verifying exit node routes propagated to client")
				})
			}
		}
	}
}

// assertTracerouteViaIPWithCollect is a version of assertTracerouteViaIP that works with assert.CollectT.
func assertTracerouteViaIPWithCollect(c *assert.CollectT, tr util.Traceroute, ip netip.Addr) {
	assert.NotNil(c, tr)
	assert.True(c, tr.Success)
	assert.NoError(c, tr.Err) //nolint:testifylint // using assert.CollectT
	assert.NotEmpty(c, tr.Route)
	// Since we're inside EventuallyWithT, we can't use require.Greater with t
	// but assert.NotEmpty above ensures len(tr.Route) > 0
	if len(tr.Route) > 0 {
		assert.Equal(c, tr.Route[0].IP.String(), ip.String())
	}
}

func SortPeerStatus(a, b *ipnstate.PeerStatus) int {
	return cmp.Compare(a.ID, b.ID)
}

func printCurrentRouteMap(t *testing.T, routers ...*ipnstate.PeerStatus) {
	t.Helper()
	t.Logf("== Current routing map ==")
	slices.SortFunc(routers, SortPeerStatus)

	for _, router := range routers {
		got := filterNonRoutes(router)
		t.Logf("  Router %s (%s) is serving:", router.HostName, router.ID)
		t.Logf("    AllowedIPs: %v", got)

		if router.PrimaryRoutes != nil {
			t.Logf("    PrimaryRoutes: %v", router.PrimaryRoutes.AsSlice())
		}
	}
}

// filterNonRoutes returns the list of routes that a [ipnstate.PeerStatus] is serving.
func filterNonRoutes(status *ipnstate.PeerStatus) []netip.Prefix {
	return slicesx.Filter(nil, status.AllowedIPs.AsSlice(), func(p netip.Prefix) bool {
		if tsaddr.IsExitRoute(p) {
			return true
		}

		return !slices.ContainsFunc(status.TailscaleIPs, p.Contains)
	})
}

func requirePeerSubnetRoutesWithCollect(c *assert.CollectT, status *ipnstate.PeerStatus, expected []netip.Prefix) {
	if status.AllowedIPs.Len() <= 2 && len(expected) != 0 {
		assert.Fail(c, fmt.Sprintf("peer %s (%s) has no subnet routes, expected %v", status.HostName, status.ID, expected))
		return
	}

	if len(expected) == 0 {
		expected = []netip.Prefix{}
	}

	got := filterNonRoutes(status)

	if diff := cmpdiff.Diff(expected, got, util.PrefixComparer, cmpopts.EquateEmpty()); diff != "" {
		assert.Fail(c, fmt.Sprintf("peer %s (%s) subnet routes, unexpected result (-want +got):\n%s", status.HostName, status.ID, diff))
	}
}

func requireNodeRouteCountWithCollect(c *assert.CollectT, node *v1.Node, announced, approved, subnet int) {
	assert.Lenf(c, node.GetAvailableRoutes(), announced, "expected %q announced routes(%v) to have %d route, had %d", node.GetName(), node.GetAvailableRoutes(), announced, len(node.GetAvailableRoutes()))
	assert.Lenf(c, node.GetApprovedRoutes(), approved, "expected %q approved routes(%v) to have %d route, had %d", node.GetName(), node.GetApprovedRoutes(), approved, len(node.GetApprovedRoutes()))
	assert.Lenf(c, node.GetSubnetRoutes(), subnet, "expected %q subnet routes(%v) to have %d route, had %d", node.GetName(), node.GetSubnetRoutes(), subnet, len(node.GetSubnetRoutes()))
}

// TestSubnetRouteACLFiltering tests that a node can only access subnet routes
// that are explicitly allowed in the ACL.
func TestSubnetRouteACLFiltering(t *testing.T) {
	IntegrationSkip(t)

	// Use router and node users for better clarity
	routerUser := "router"
	nodeUser := "node"

	spec := ScenarioSpec{
		NodesPerUser: 1,
		Users:        []string{routerUser, nodeUser},
		Networks: map[string][]string{
			"usernet1": {routerUser, nodeUser},
		},
		ExtraService: map[string][]extraServiceFunc{
			"usernet1": {Webservice},
		},
		// We build the head image with curl and traceroute, so only use
		// that for this test.
		Versions: []string{"head"},
	}

	scenario, err := NewScenario(spec)

	require.NoErrorf(t, err, "failed to create scenario: %s", err)
	defer scenario.ShutdownAssertNoPanics(t)

	// Set up the ACL policy that allows the node to access only one of the subnet routes (10.10.10.0/24)
	aclPolicyStr := `{
		"hosts": {
			"router": "100.64.0.1/32",
			"node": "100.64.0.2/32"
		},
		"acls": [
			{
				"action": "accept",
				"src": [
					"*"
				],
				"dst": [
					"router:8000"
				]
			},
			{
				"action": "accept",
				"src": [
					"node"
				],
				"dst": [
					"*:*"
				]
			}
		]
	}`

	route, err := scenario.SubnetOfNetwork("usernet1")
	require.NoError(t, err)

	services, err := scenario.Services("usernet1")
	require.NoError(t, err)
	require.Len(t, services, 1)

	usernet1, err := scenario.Network("usernet1")
	require.NoError(t, err)

	web := services[0]
	webip := netip.MustParseAddr(web.GetIPInNetwork(usernet1))
	weburl := fmt.Sprintf("http://%s/etc/hostname", webip)
	t.Logf("webservice: %s, %s", webip.String(), weburl)

	aclPolicy := &policyv2.Policy{}
	err = json.Unmarshal([]byte(aclPolicyStr), aclPolicy)
	require.NoError(t, err)

	err = scenario.CreateHeadscaleEnv([]tsic.Option{
		tsic.WithAcceptRoutes(),
	}, hsic.WithTestName("routeaclfilter"),
		hsic.WithACLPolicy(aclPolicy),
		hsic.WithPolicyMode(types.PolicyModeDB), // test updates policy at runtime via CLI
	)
	requireNoErrHeadscaleEnv(t, err)

	err = scenario.WaitForTailscaleSync()
	requireNoErrSync(t, err)

	headscale, err := scenario.Headscale()
	requireNoErrGetHeadscale(t, err)

	// Get the router and node clients by user
	routerClients, err := scenario.ListTailscaleClients(routerUser)
	require.NoError(t, err)
	require.Len(t, routerClients, 1)
	routerClient := routerClients[0]

	nodeClients, err := scenario.ListTailscaleClients(nodeUser)
	require.NoError(t, err)
	require.Len(t, nodeClients, 1)
	nodeClient := nodeClients[0]

	routerIP, err := routerClient.IPv4()
	require.NoError(t, err, "failed to get router IPv4")
	nodeIP, err := nodeClient.IPv4()
	require.NoError(t, err, "failed to get node IPv4")

	aclPolicy.Hosts = policyv2.Hosts{
		policyv2.Host(routerUser): policyv2.Prefix(must.Get(routerIP.Prefix(32))),
		policyv2.Host(nodeUser):   policyv2.Prefix(must.Get(nodeIP.Prefix(32))),
	}
	aclPolicy.ACLs[1].Destinations = []policyv2.AliasWithPorts{
		aliasWithPorts(prefixp(route.String()), tailcfg.PortRangeAny),
	}
	require.NoError(t, headscale.SetPolicy(aclPolicy))

	// Set up the subnet routes for the router
	routes := []netip.Prefix{
		*route,                                 // This should be accessible by the client
		netip.MustParsePrefix("10.10.11.0/24"), // These should NOT be accessible
		netip.MustParsePrefix("10.10.12.0/24"),
	}

	routeArg := "--advertise-routes=" + routes[0].String() + "," + routes[1].String() + "," + routes[2].String()
	command := []string{
		"tailscale",
		"set",
		routeArg,
	}

	_, _, err = routerClient.Execute(command)
	require.NoErrorf(t, err, "failed to advertise routes: %s", err)

	err = scenario.WaitForTailscaleSync()
	requireNoErrSync(t, err)

	var routerNode, nodeNode *v1.Node
	// Wait for route advertisements to propagate to NodeStore
	assert.EventuallyWithT(t, func(ct *assert.CollectT) {
		// List nodes and verify the router has 3 available routes
		nodes, err := headscale.NodesByUser()
		assert.NoError(ct, err)
		assert.Len(ct, nodes, 2)

		// Find the router node
		routerNode = nodes[routerUser][0]
		nodeNode = nodes[nodeUser][0]

		assert.NotNil(ct, routerNode, "Router node not found")
		assert.NotNil(ct, nodeNode, "Client node not found")

		// Check that the router has 3 routes available but not approved yet
		requireNodeRouteCountWithCollect(ct, routerNode, 3, 0, 0)
		requireNodeRouteCountWithCollect(ct, nodeNode, 0, 0, 0)
	}, integrationutil.ScaledTimeout(10*time.Second), 100*time.Millisecond, "route advertisements should propagate to router node")

	// Approve all routes for the router
	_, err = headscale.ApproveRoutes(
		routerNode.GetId(),
		util.MustStringsToPrefixes(routerNode.GetAvailableRoutes()),
	)
	require.NoError(t, err)

	// Wait for route state changes to propagate
	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		// List nodes and verify the router has 3 available routes
		var err error

		nodes, err := headscale.NodesByUser()
		assert.NoError(c, err)
		assert.Len(c, nodes, 2)

		// Find the router node
		routerNode = nodes[routerUser][0]

		// Check that the router has 3 routes now approved and available
		requireNodeRouteCountWithCollect(c, routerNode, 3, 3, 3)
	}, integrationutil.ScaledTimeout(15*time.Second), 500*time.Millisecond, "route state changes should propagate")

	// Now check the client node status
	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		nodeStatus, err := nodeClient.Status()
		assert.NoError(c, err)

		routerStatus, err := routerClient.Status()
		assert.NoError(c, err)

		// Check that the node can see the subnet routes from the router
		routerPeerStatus := nodeStatus.Peer[routerStatus.Self.PublicKey]

		// The node should only have 1 subnet route
		requirePeerSubnetRoutesWithCollect(c, routerPeerStatus, []netip.Prefix{*route})
	}, integrationutil.ScaledTimeout(5*time.Second), 200*time.Millisecond, "Verifying node sees filtered subnet routes")

	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		result, err := nodeClient.Curl(weburl)
		assert.NoError(c, err)
		assert.Len(c, result, 13)
	}, integrationutil.ScaledTimeout(60*time.Second), 200*time.Millisecond, "Verifying node can reach webservice through allowed route")

	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		tr, err := nodeClient.Traceroute(webip)
		assert.NoError(c, err)

		ip, err := routerClient.IPv4()
		if !assert.NoError(c, err, "failed to get IPv4 for routerClient") {
			return
		}

		assertTracerouteViaIPWithCollect(c, tr, ip)
	}, integrationutil.ScaledTimeout(60*time.Second), 200*time.Millisecond, "Verifying traceroute goes through router")
}

// TestGrantViaSubnetSteering validates that via grants steer different source
// groups through different tagged subnet routers to the same destination.
// Per Tailscale docs, via enables traffic steering: routing specific source
// groups through specific tagged intermediate nodes (subnet routers).
func TestGrantViaSubnetSteering(t *testing.T) {
	IntegrationSkip(t)

	assertTimeout := 60 * time.Second

	spec := ScenarioSpec{
		NodesPerUser: 0,
		Users:        []string{"router", "client"},
		Networks: map[string][]string{
			"usernet1": {"router"},
			"usernet2": {"client"},
		},
		ExtraService: map[string][]extraServiceFunc{
			"usernet1": {Webservice},
		},
		Versions: []string{"head"},
	}

	scenario, err := NewScenario(spec)

	require.NoErrorf(t, err, "failed to create scenario: %s", err)
	defer scenario.ShutdownAssertNoPanics(t)

	// Get the subnet for usernet1 before creating headscale
	// (needed for policy construction).
	route, err := scenario.SubnetOfNetwork("usernet1")
	require.NoError(t, err)

	pol := &policyv2.Policy{
		TagOwners: policyv2.TagOwners{
			policyv2.Tag("tag:router-a"): policyv2.Owners{usernameOwner("router@")},
			policyv2.Tag("tag:router-b"): policyv2.Owners{usernameOwner("router@")},
			policyv2.Tag("tag:group-a"):  policyv2.Owners{usernameOwner("client@")},
			policyv2.Tag("tag:group-b"):  policyv2.Owners{usernameOwner("client@")},
		},
		Grants: []policyv2.Grant{
			// Allow all tagged nodes to communicate with each other (peer connectivity).
			// Uses tag-based src/dst to avoid creating rules for the subnet prefix,
			// so only via grants control subnet route visibility.
			{
				Sources: policyv2.Aliases{
					tagp("tag:router-a"), tagp("tag:router-b"),
					tagp("tag:group-a"), tagp("tag:group-b"),
				},
				Destinations: policyv2.Aliases{
					tagp("tag:router-a"), tagp("tag:router-b"),
					tagp("tag:group-a"), tagp("tag:group-b"),
				},
				InternetProtocols: []policyv2.ProtocolPort{
					{Protocol: "*", Ports: []tailcfg.PortRange{tailcfg.PortRangeAny}},
				},
			},
			// Via grant: steer tag:group-a traffic to usernet1 subnet through tag:router-a.
			{
				Sources:      policyv2.Aliases{tagp("tag:group-a")},
				Destinations: policyv2.Aliases{prefixp(route.String())},
				InternetProtocols: []policyv2.ProtocolPort{
					{Protocol: "*", Ports: []tailcfg.PortRange{tailcfg.PortRangeAny}},
				},
				Via: []policyv2.Tag{policyv2.Tag("tag:router-a")},
			},
			// Via grant: steer tag:group-b traffic to usernet1 subnet through tag:router-b.
			{
				Sources:      policyv2.Aliases{tagp("tag:group-b")},
				Destinations: policyv2.Aliases{prefixp(route.String())},
				InternetProtocols: []policyv2.ProtocolPort{
					{Protocol: "*", Ports: []tailcfg.PortRange{tailcfg.PortRangeAny}},
				},
				Via: []policyv2.Tag{policyv2.Tag("tag:router-b")},
			},
		},
		AutoApprovers: policyv2.AutoApproverPolicy{
			Routes: map[netip.Prefix]policyv2.AutoApprovers{
				*route: {tagApprover("tag:router-a"), tagApprover("tag:router-b")},
			},
		},
	}

	headscale, err := scenario.Headscale(
		hsic.WithTestName("grantvia-subnet"),
		hsic.WithACLPolicy(pol),
		hsic.WithPolicyMode(types.PolicyModeDB),
	)
	requireNoErrGetHeadscale(t, err)

	usernet1, err := scenario.Network("usernet1")
	require.NoError(t, err)
	usernet2, err := scenario.Network("usernet2")
	require.NoError(t, err)

	// Create users on headscale server.
	_, err = scenario.CreateUser("router")
	require.NoError(t, err)
	_, err = scenario.CreateUser("client")
	require.NoError(t, err)

	userMap, err := headscale.MapUsers()
	require.NoError(t, err)

	// Create Router A (tag:router-a) on usernet1.
	routerA, err := scenario.CreateTailscaleNode("head",
		tsic.WithNetwork(usernet1),
		tsic.WithAcceptRoutes(),
	)
	require.NoError(t, err)

	defer func() { _, _, _ = routerA.Shutdown() }()

	pakRouterA, err := scenario.CreatePreAuthKeyWithTags(
		userMap["router"].GetId(), false, false, []string{"tag:router-a"},
	)
	require.NoError(t, err)
	err = routerA.Login(headscale.GetEndpoint(), pakRouterA.GetKey())
	require.NoError(t, err)
	err = routerA.WaitForRunning(30 * time.Second)
	require.NoError(t, err)

	// Create Router B (tag:router-b) on usernet1.
	routerB, err := scenario.CreateTailscaleNode("head",
		tsic.WithNetwork(usernet1),
		tsic.WithAcceptRoutes(),
	)
	require.NoError(t, err)

	defer func() { _, _, _ = routerB.Shutdown() }()

	pakRouterB, err := scenario.CreatePreAuthKeyWithTags(
		userMap["router"].GetId(), false, false, []string{"tag:router-b"},
	)
	require.NoError(t, err)
	err = routerB.Login(headscale.GetEndpoint(), pakRouterB.GetKey())
	require.NoError(t, err)
	err = routerB.WaitForRunning(30 * time.Second)
	require.NoError(t, err)

	// Create Client A (tag:group-a) on usernet2.
	clientA, err := scenario.CreateTailscaleNode("head",
		tsic.WithNetwork(usernet2),
		tsic.WithAcceptRoutes(),
	)
	require.NoError(t, err)

	defer func() { _, _, _ = clientA.Shutdown() }()

	pakClientA, err := scenario.CreatePreAuthKeyWithTags(
		userMap["client"].GetId(), false, false, []string{"tag:group-a"},
	)
	require.NoError(t, err)
	err = clientA.Login(headscale.GetEndpoint(), pakClientA.GetKey())
	require.NoError(t, err)
	err = clientA.WaitForRunning(30 * time.Second)
	require.NoError(t, err)

	// Create Client B (tag:group-b) on usernet2.
	clientB, err := scenario.CreateTailscaleNode("head",
		tsic.WithNetwork(usernet2),
		tsic.WithAcceptRoutes(),
	)
	require.NoError(t, err)

	defer func() { _, _, _ = clientB.Shutdown() }()

	pakClientB, err := scenario.CreatePreAuthKeyWithTags(
		userMap["client"].GetId(), false, false, []string{"tag:group-b"},
	)
	require.NoError(t, err)
	err = clientB.Login(headscale.GetEndpoint(), pakClientB.GetKey())
	require.NoError(t, err)
	err = clientB.WaitForRunning(30 * time.Second)
	require.NoError(t, err)

	// Wait for all peers to see each other (4 nodes, each sees 3 peers).
	allNodes := []TailscaleClient{routerA, routerB, clientA, clientB}
	for _, node := range allNodes {
		err = node.WaitForPeers(len(allNodes)-1, 60*time.Second, 1*time.Second)
		require.NoErrorf(t, err, "node %s failed to see all peers", node.Hostname())
	}

	// Both routers advertise usernet1 subnet.
	for _, router := range []TailscaleClient{routerA, routerB} {
		command := []string{
			"tailscale", "set",
			"--advertise-routes=" + route.String(),
		}
		_, _, err = router.Execute(command)
		require.NoErrorf(t, err, "failed to advertise route on %s", router.Hostname())
	}

	// Wait for auto-approval on both routers.
	// Only check announced and approved counts. SubnetRoutes (primary election)
	// is a global single-primary-per-prefix model, so only one router wins.
	// Via steering should override this per-client, which is what we test below.
	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		nodes, err := headscale.ListNodes()
		assert.NoError(c, err)

		routerANode := MustFindNode(routerA.Hostname(), nodes)
		t.Logf("Router A %s: announced=%v, approved=%v, subnet=%v",
			routerANode.GetName(),
			routerANode.GetAvailableRoutes(),
			routerANode.GetApprovedRoutes(),
			routerANode.GetSubnetRoutes())
		assert.Len(c, routerANode.GetAvailableRoutes(), 1, "Router A should have 1 announced route")
		assert.Len(c, routerANode.GetApprovedRoutes(), 1, "Router A should have 1 approved route")

		routerBNode := MustFindNode(routerB.Hostname(), nodes)
		t.Logf("Router B %s: announced=%v, approved=%v, subnet=%v",
			routerBNode.GetName(),
			routerBNode.GetAvailableRoutes(),
			routerBNode.GetApprovedRoutes(),
			routerBNode.GetSubnetRoutes())
		assert.Len(c, routerBNode.GetAvailableRoutes(), 1, "Router B should have 1 announced route")
		assert.Len(c, routerBNode.GetApprovedRoutes(), 1, "Router B should have 1 approved route")
	}, assertTimeout, 500*time.Millisecond, "Both routers should have auto-approved routes")

	// Get webservice info.
	services, err := scenario.Services("usernet1")
	require.NoError(t, err)
	require.Len(t, services, 1)

	web := services[0]
	webip := netip.MustParseAddr(web.GetIPInNetwork(usernet1))
	weburl := fmt.Sprintf("http://%s/etc/hostname", webip)
	t.Logf("webservice: %s, %s", webip.String(), weburl)

	// Verify Client A sees only Router A's subnet route (via steering).
	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		status, err := clientA.Status()
		assert.NoError(c, err)

		routerAID := routerA.MustID()
		routerBID := routerB.MustID()

		for _, peerKey := range status.Peers() {
			peerStatus := status.Peer[peerKey]

			switch peerStatus.ID {
			case routerAID.StableID():
				// Client A should see Router A's subnet route.
				t.Logf("Client A sees Router A: AllowedIPs=%v, PrimaryRoutes=%v",
					peerStatus.AllowedIPs, peerStatus.PrimaryRoutes)
				requirePeerSubnetRoutesWithCollect(c, peerStatus, []netip.Prefix{*route})
			case routerBID.StableID():
				// Client A should NOT see Router B's subnet route.
				t.Logf("Client A sees Router B: AllowedIPs=%v, PrimaryRoutes=%v",
					peerStatus.AllowedIPs, peerStatus.PrimaryRoutes)
				requirePeerSubnetRoutesWithCollect(c, peerStatus, nil)
			}
		}
	}, assertTimeout, 500*time.Millisecond, "Client A should see only Router A's subnet route")

	// Verify Client B sees only Router B's subnet route (via steering).
	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		status, err := clientB.Status()
		assert.NoError(c, err)

		routerAID := routerA.MustID()
		routerBID := routerB.MustID()

		for _, peerKey := range status.Peers() {
			peerStatus := status.Peer[peerKey]

			switch peerStatus.ID {
			case routerAID.StableID():
				// Client B should NOT see Router A's subnet route.
				t.Logf("Client B sees Router A: AllowedIPs=%v, PrimaryRoutes=%v",
					peerStatus.AllowedIPs, peerStatus.PrimaryRoutes)
				requirePeerSubnetRoutesWithCollect(c, peerStatus, nil)
			case routerBID.StableID():
				// Client B should see Router B's subnet route.
				t.Logf("Client B sees Router B: AllowedIPs=%v, PrimaryRoutes=%v",
					peerStatus.AllowedIPs, peerStatus.PrimaryRoutes)
				requirePeerSubnetRoutesWithCollect(c, peerStatus, []netip.Prefix{*route})
			}
		}
	}, assertTimeout, 500*time.Millisecond, "Client B should see only Router B's subnet route")

	// Verify Client A can reach the webservice.
	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		result, err := clientA.Curl(weburl)
		assert.NoError(c, err)
		assert.Len(c, result, 13)
	}, assertTimeout, 200*time.Millisecond, "Client A should reach webservice")

	// Verify Client B can reach the webservice.
	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		result, err := clientB.Curl(weburl)
		assert.NoError(c, err)
		assert.Len(c, result, 13)
	}, assertTimeout, 200*time.Millisecond, "Client B should reach webservice")

	// Verify Client A's traffic goes through Router A.
	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		tr, err := clientA.Traceroute(webip)
		assert.NoError(c, err)

		ip, err := routerA.IPv4()
		if !assert.NoError(c, err, "failed to get IPv4 for routerA") {
			return
		}

		assertTracerouteViaIPWithCollect(c, tr, ip)
	}, assertTimeout, 200*time.Millisecond, "Client A traceroute should go through Router A")

	// Verify Client B's traffic goes through Router B.
	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		tr, err := clientB.Traceroute(webip)
		assert.NoError(c, err)

		ip, err := routerB.IPv4()
		if !assert.NoError(c, err, "failed to get IPv4 for routerB") {
			return
		}

		assertTracerouteViaIPWithCollect(c, tr, ip)
	}, assertTimeout, 200*time.Millisecond, "Client B traceroute should go through Router B")
}

// TestGrantViaExitNodeSteering validates that via grants steer different
// source groups through different tagged exit nodes for internet traffic.
// Per Tailscale docs, via with autogroup:internet steers exit node traffic
// through specific tagged nodes.
func TestGrantViaExitNodeSteering(t *testing.T) {
	IntegrationSkip(t)

	assertTimeout := 60 * time.Second

	spec := ScenarioSpec{
		NodesPerUser: 0,
		Users:        []string{"exit", "client"},
		Networks: map[string][]string{
			"usernet1": {"exit"},
			"usernet2": {"client"},
		},
		ExtraService: map[string][]extraServiceFunc{
			"usernet1": {Webservice},
		},
		Versions: []string{"head"},
	}

	scenario, err := NewScenario(spec)

	require.NoErrorf(t, err, "failed to create scenario: %s", err)
	defer scenario.ShutdownAssertNoPanics(t)

	pol := &policyv2.Policy{
		TagOwners: policyv2.TagOwners{
			policyv2.Tag("tag:exit-a"):  policyv2.Owners{usernameOwner("exit@")},
			policyv2.Tag("tag:exit-b"):  policyv2.Owners{usernameOwner("exit@")},
			policyv2.Tag("tag:group-a"): policyv2.Owners{usernameOwner("client@")},
			policyv2.Tag("tag:group-b"): policyv2.Owners{usernameOwner("client@")},
		},
		Grants: []policyv2.Grant{
			// Allow all tagged nodes to communicate with each other (peer connectivity).
			{
				Sources: policyv2.Aliases{
					tagp("tag:exit-a"), tagp("tag:exit-b"),
					tagp("tag:group-a"), tagp("tag:group-b"),
				},
				Destinations: policyv2.Aliases{
					tagp("tag:exit-a"), tagp("tag:exit-b"),
					tagp("tag:group-a"), tagp("tag:group-b"),
				},
				InternetProtocols: []policyv2.ProtocolPort{
					{Protocol: "*", Ports: []tailcfg.PortRange{tailcfg.PortRangeAny}},
				},
			},
			// Via grant: steer tag:group-a internet traffic through tag:exit-a.
			{
				Sources:      policyv2.Aliases{tagp("tag:group-a")},
				Destinations: policyv2.Aliases{autogroupp("autogroup:internet")},
				InternetProtocols: []policyv2.ProtocolPort{
					{Protocol: "*", Ports: []tailcfg.PortRange{tailcfg.PortRangeAny}},
				},
				Via: []policyv2.Tag{policyv2.Tag("tag:exit-a")},
			},
			// Via grant: steer tag:group-b internet traffic through tag:exit-b.
			{
				Sources:      policyv2.Aliases{tagp("tag:group-b")},
				Destinations: policyv2.Aliases{autogroupp("autogroup:internet")},
				InternetProtocols: []policyv2.ProtocolPort{
					{Protocol: "*", Ports: []tailcfg.PortRange{tailcfg.PortRangeAny}},
				},
				Via: []policyv2.Tag{policyv2.Tag("tag:exit-b")},
			},
		},
		AutoApprovers: policyv2.AutoApproverPolicy{
			ExitNode: policyv2.AutoApprovers{
				tagApprover("tag:exit-a"),
				tagApprover("tag:exit-b"),
			},
		},
	}

	headscale, err := scenario.Headscale(
		hsic.WithTestName("grantvia-exit"),
		hsic.WithACLPolicy(pol),
		hsic.WithPolicyMode(types.PolicyModeDB),
	)
	requireNoErrGetHeadscale(t, err)

	usernet1, err := scenario.Network("usernet1")
	require.NoError(t, err)
	usernet2, err := scenario.Network("usernet2")
	require.NoError(t, err)

	// Create users on headscale server.
	_, err = scenario.CreateUser("exit")
	require.NoError(t, err)
	_, err = scenario.CreateUser("client")
	require.NoError(t, err)

	userMap, err := headscale.MapUsers()
	require.NoError(t, err)

	// Create Exit A (tag:exit-a) on usernet1.
	exitA, err := scenario.CreateTailscaleNode("head",
		tsic.WithNetwork(usernet1),
		tsic.WithAcceptRoutes(),
	)
	require.NoError(t, err)

	defer func() { _, _, _ = exitA.Shutdown() }()

	pakExitA, err := scenario.CreatePreAuthKeyWithTags(
		userMap["exit"].GetId(), false, false, []string{"tag:exit-a"},
	)
	require.NoError(t, err)
	err = exitA.Login(headscale.GetEndpoint(), pakExitA.GetKey())
	require.NoError(t, err)
	err = exitA.WaitForRunning(30 * time.Second)
	require.NoError(t, err)

	// Create Exit B (tag:exit-b) on usernet1.
	exitB, err := scenario.CreateTailscaleNode("head",
		tsic.WithNetwork(usernet1),
		tsic.WithAcceptRoutes(),
	)
	require.NoError(t, err)

	defer func() { _, _, _ = exitB.Shutdown() }()

	pakExitB, err := scenario.CreatePreAuthKeyWithTags(
		userMap["exit"].GetId(), false, false, []string{"tag:exit-b"},
	)
	require.NoError(t, err)
	err = exitB.Login(headscale.GetEndpoint(), pakExitB.GetKey())
	require.NoError(t, err)
	err = exitB.WaitForRunning(30 * time.Second)
	require.NoError(t, err)

	// Create Client A (tag:group-a) on usernet2.
	clientA, err := scenario.CreateTailscaleNode("head",
		tsic.WithNetwork(usernet2),
		tsic.WithAcceptRoutes(),
	)
	require.NoError(t, err)

	defer func() { _, _, _ = clientA.Shutdown() }()

	pakClientA, err := scenario.CreatePreAuthKeyWithTags(
		userMap["client"].GetId(), false, false, []string{"tag:group-a"},
	)
	require.NoError(t, err)
	err = clientA.Login(headscale.GetEndpoint(), pakClientA.GetKey())
	require.NoError(t, err)
	err = clientA.WaitForRunning(30 * time.Second)
	require.NoError(t, err)

	// Create Client B (tag:group-b) on usernet2.
	clientB, err := scenario.CreateTailscaleNode("head",
		tsic.WithNetwork(usernet2),
		tsic.WithAcceptRoutes(),
	)
	require.NoError(t, err)

	defer func() { _, _, _ = clientB.Shutdown() }()

	pakClientB, err := scenario.CreatePreAuthKeyWithTags(
		userMap["client"].GetId(), false, false, []string{"tag:group-b"},
	)
	require.NoError(t, err)
	err = clientB.Login(headscale.GetEndpoint(), pakClientB.GetKey())
	require.NoError(t, err)
	err = clientB.WaitForRunning(30 * time.Second)
	require.NoError(t, err)

	// Wait for all peers to see each other (4 nodes, each sees 3 peers).
	allNodes := []TailscaleClient{exitA, exitB, clientA, clientB}
	for _, node := range allNodes {
		err = node.WaitForPeers(len(allNodes)-1, 60*time.Second, 1*time.Second)
		require.NoErrorf(t, err, "node %s failed to see all peers", node.Hostname())
	}

	// Both exit nodes advertise exit routes.
	for _, exitNode := range []TailscaleClient{exitA, exitB} {
		command := []string{
			"tailscale", "set",
			"--advertise-exit-node",
		}
		_, _, err = exitNode.Execute(command)
		require.NoErrorf(t, err, "failed to advertise exit node on %s", exitNode.Hostname())
	}

	// Wait for auto-approval on both exit nodes.
	// Exit routes = 2 per node (0.0.0.0/0 + ::/0). Only check announced/approved;
	// primary election may only give one node the subnet designation.
	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		nodes, err := headscale.ListNodes()
		assert.NoError(c, err)

		exitANode := MustFindNode(exitA.Hostname(), nodes)
		t.Logf("Exit A %s: announced=%v, approved=%v, subnet=%v",
			exitANode.GetName(),
			exitANode.GetAvailableRoutes(),
			exitANode.GetApprovedRoutes(),
			exitANode.GetSubnetRoutes())
		assert.Len(c, exitANode.GetAvailableRoutes(), 2, "Exit A should have 2 announced routes")
		assert.Len(c, exitANode.GetApprovedRoutes(), 2, "Exit A should have 2 approved routes")

		exitBNode := MustFindNode(exitB.Hostname(), nodes)
		t.Logf("Exit B %s: announced=%v, approved=%v, subnet=%v",
			exitBNode.GetName(),
			exitBNode.GetAvailableRoutes(),
			exitBNode.GetApprovedRoutes(),
			exitBNode.GetSubnetRoutes())
		assert.Len(c, exitBNode.GetAvailableRoutes(), 2, "Exit B should have 2 announced routes")
		assert.Len(c, exitBNode.GetApprovedRoutes(), 2, "Exit B should have 2 approved routes")
	}, assertTimeout, 500*time.Millisecond, "Both exit nodes should have auto-approved exit routes")

	exitAID := exitA.MustID()
	exitBID := exitB.MustID()

	// Via steering: Client A should see exit routes ONLY on Exit A (not Exit B).
	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		status, err := clientA.Status()
		assert.NoError(c, err)

		for _, peerKey := range status.Peers() {
			peerStatus := status.Peer[peerKey]

			switch peerStatus.ID {
			case exitAID.StableID():
				// Client A should see Exit A's exit routes.
				t.Logf("Client A sees Exit A: AllowedIPs=%v, ExitNode=%v",
					peerStatus.AllowedIPs, peerStatus.ExitNode)
				got := filterNonRoutes(peerStatus)
				assert.NotEmpty(c, got, "Client A should see Exit A's exit routes")
			case exitBID.StableID():
				// Client A should NOT see Exit B's exit routes.
				t.Logf("Client A sees Exit B: AllowedIPs=%v, ExitNode=%v",
					peerStatus.AllowedIPs, peerStatus.ExitNode)
				got := filterNonRoutes(peerStatus)
				assert.Empty(c, got, "Client A should NOT see Exit B's exit routes")
			}
		}
	}, assertTimeout, 500*time.Millisecond, "Client A should see exit routes only via Exit A")

	// Via steering: Client B should see exit routes ONLY on Exit B (not Exit A).
	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		status, err := clientB.Status()
		assert.NoError(c, err)

		for _, peerKey := range status.Peers() {
			peerStatus := status.Peer[peerKey]

			switch peerStatus.ID {
			case exitBID.StableID():
				// Client B should see Exit B's exit routes.
				t.Logf("Client B sees Exit B: AllowedIPs=%v, ExitNode=%v",
					peerStatus.AllowedIPs, peerStatus.ExitNode)
				got := filterNonRoutes(peerStatus)
				assert.NotEmpty(c, got, "Client B should see Exit B's exit routes")
			case exitAID.StableID():
				// Client B should NOT see Exit A's exit routes.
				t.Logf("Client B sees Exit A: AllowedIPs=%v, ExitNode=%v",
					peerStatus.AllowedIPs, peerStatus.ExitNode)
				got := filterNonRoutes(peerStatus)
				assert.Empty(c, got, "Client B should NOT see Exit A's exit routes")
			}
		}
	}, assertTimeout, 500*time.Millisecond, "Client B should see exit routes only via Exit B")

	services, err := scenario.Services("usernet1")
	require.NoError(t, err)
	require.Len(t, services, 1)

	web := services[0]
	webip := netip.MustParseAddr(web.GetIPInNetwork(usernet1))
	weburl := fmt.Sprintf("http://%s/etc/hostname", webip)
	t.Logf("webservice: %s, %s", webip.String(), weburl)

	// Negative test: Client A tries to set the WRONG exit node (Exit B, not designated by via).
	// Via steering removes exit routes from non-designated exit nodes in the network map,
	// so the Tailscale client itself rejects the command since Exit B has no exit routes
	// from Client A's perspective.
	exitBStatus := exitB.MustStatus()
	wrongExitCmd := []string{
		"tailscale", "set",
		"--exit-node=" + exitBStatus.Self.DNSName,
	}
	_, _, err = clientA.Execute(wrongExitCmd)
	require.Error(t, err, "Client A should not be able to set non-designated Exit B as exit node")

	// Positive test: Each client selects the exit node designated by via.
	exitAStatus := exitA.MustStatus()
	commandA := []string{
		"tailscale", "set",
		"--exit-node=" + exitAStatus.Self.DNSName,
	}
	_, _, err = clientA.Execute(commandA)
	require.NoError(t, err, "Client A failed to set exit node to Exit A")

	commandB := []string{
		"tailscale", "set",
		"--exit-node=" + exitBStatus.Self.DNSName,
	}
	_, _, err = clientB.Execute(commandB)
	require.NoError(t, err, "Client B failed to set exit node to Exit B")

	// Verify traffic flows through the via-designated exit nodes.
	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		result, err := clientA.Curl(weburl)
		assert.NoError(c, err)
		assert.Len(c, result, 13)
	}, assertTimeout, 200*time.Millisecond, "Client A should reach webservice via Exit A")

	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		tr, err := clientA.Traceroute(webip)
		assert.NoError(c, err)

		ip, err := exitA.IPv4()
		if !assert.NoError(c, err, "failed to get IPv4 for exitA") {
			return
		}

		assertTracerouteViaIPWithCollect(c, tr, ip)
	}, assertTimeout, 200*time.Millisecond, "Client A traceroute should go through Exit A")

	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		result, err := clientB.Curl(weburl)
		assert.NoError(c, err)
		assert.Len(c, result, 13)
	}, assertTimeout, 200*time.Millisecond, "Client B should reach webservice via Exit B")

	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		tr, err := clientB.Traceroute(webip)
		assert.NoError(c, err)

		ip, err := exitB.IPv4()
		if !assert.NoError(c, err, "failed to get IPv4 for exitB") {
			return
		}

		assertTracerouteViaIPWithCollect(c, tr, ip)
	}, assertTimeout, 200*time.Millisecond, "Client B traceroute should go through Exit B")
}

// TestGrantViaMixedSteering validates cross-steering when the same servers
// advertise both subnet routes and exit routes simultaneously. Via grants
// steer each client group through different servers for subnet vs exit traffic:
//   - group-a uses server-a for subnet, server-b for exit
//   - group-b uses server-b for subnet, server-a for exit
//
// Uses three networks:
//   - usernet1: servers + webservice (subnet destination)
//   - usernet2: clients
//   - externet: webservice reachable only via exit nodes (servers also connected)
func TestGrantViaMixedSteering(t *testing.T) {
	IntegrationSkip(t)

	assertTimeout := 60 * time.Second

	spec := ScenarioSpec{
		NodesPerUser: 0,
		Users:        []string{"server", "client"},
		Networks: map[string][]string{
			"usernet1": {"server"},
			"usernet2": {"client"},
			"externet": {},
		},
		ExtraService: map[string][]extraServiceFunc{
			"usernet1": {Webservice},
			"externet": {Webservice},
		},
		Versions: []string{"head"},
	}

	scenario, err := NewScenario(spec)

	require.NoErrorf(t, err, "failed to create scenario: %s", err)
	defer scenario.ShutdownAssertNoPanics(t)

	route, err := scenario.SubnetOfNetwork("usernet1")
	require.NoError(t, err)

	pol := &policyv2.Policy{
		TagOwners: policyv2.TagOwners{
			policyv2.Tag("tag:server-a"): policyv2.Owners{usernameOwner("server@")},
			policyv2.Tag("tag:server-b"): policyv2.Owners{usernameOwner("server@")},
			policyv2.Tag("tag:group-a"):  policyv2.Owners{usernameOwner("client@")},
			policyv2.Tag("tag:group-b"):  policyv2.Owners{usernameOwner("client@")},
		},
		Grants: []policyv2.Grant{
			// Allow all tagged nodes to communicate with each other (peer connectivity).
			{
				Sources: policyv2.Aliases{
					tagp("tag:server-a"), tagp("tag:server-b"),
					tagp("tag:group-a"), tagp("tag:group-b"),
				},
				Destinations: policyv2.Aliases{
					tagp("tag:server-a"), tagp("tag:server-b"),
					tagp("tag:group-a"), tagp("tag:group-b"),
				},
				InternetProtocols: []policyv2.ProtocolPort{
					{Protocol: "*", Ports: []tailcfg.PortRange{tailcfg.PortRangeAny}},
				},
			},
			// Subnet steering: group-a through server-a, group-b through server-b.
			{
				Sources:      policyv2.Aliases{tagp("tag:group-a")},
				Destinations: policyv2.Aliases{prefixp(route.String())},
				InternetProtocols: []policyv2.ProtocolPort{
					{Protocol: "*", Ports: []tailcfg.PortRange{tailcfg.PortRangeAny}},
				},
				Via: []policyv2.Tag{policyv2.Tag("tag:server-a")},
			},
			{
				Sources:      policyv2.Aliases{tagp("tag:group-b")},
				Destinations: policyv2.Aliases{prefixp(route.String())},
				InternetProtocols: []policyv2.ProtocolPort{
					{Protocol: "*", Ports: []tailcfg.PortRange{tailcfg.PortRangeAny}},
				},
				Via: []policyv2.Tag{policyv2.Tag("tag:server-b")},
			},
			// Exit steering: CROSSED - group-a through server-b, group-b through server-a.
			{
				Sources:      policyv2.Aliases{tagp("tag:group-a")},
				Destinations: policyv2.Aliases{autogroupp("autogroup:internet")},
				InternetProtocols: []policyv2.ProtocolPort{
					{Protocol: "*", Ports: []tailcfg.PortRange{tailcfg.PortRangeAny}},
				},
				Via: []policyv2.Tag{policyv2.Tag("tag:server-b")},
			},
			{
				Sources:      policyv2.Aliases{tagp("tag:group-b")},
				Destinations: policyv2.Aliases{autogroupp("autogroup:internet")},
				InternetProtocols: []policyv2.ProtocolPort{
					{Protocol: "*", Ports: []tailcfg.PortRange{tailcfg.PortRangeAny}},
				},
				Via: []policyv2.Tag{policyv2.Tag("tag:server-a")},
			},
		},
		AutoApprovers: policyv2.AutoApproverPolicy{
			Routes: map[netip.Prefix]policyv2.AutoApprovers{
				*route: {tagApprover("tag:server-a"), tagApprover("tag:server-b")},
			},
			ExitNode: policyv2.AutoApprovers{
				tagApprover("tag:server-a"),
				tagApprover("tag:server-b"),
			},
		},
	}

	headscale, err := scenario.Headscale(
		hsic.WithTestName("grantvia-mixed"),
		hsic.WithACLPolicy(pol),
		hsic.WithPolicyMode(types.PolicyModeDB),
	)
	requireNoErrGetHeadscale(t, err)

	usernet1, err := scenario.Network("usernet1")
	require.NoError(t, err)
	usernet2, err := scenario.Network("usernet2")
	require.NoError(t, err)
	externet, err := scenario.Network("externet")
	require.NoError(t, err)

	// Create users.
	_, err = scenario.CreateUser("server")
	require.NoError(t, err)
	_, err = scenario.CreateUser("client")
	require.NoError(t, err)

	userMap, err := headscale.MapUsers()
	require.NoError(t, err)

	// Create Server A (tag:server-a) on usernet1.
	serverA, err := scenario.CreateTailscaleNode("head",
		tsic.WithNetwork(usernet1),
		tsic.WithAcceptRoutes(),
	)
	require.NoError(t, err)

	defer func() { _, _, _ = serverA.Shutdown() }()

	pakServerA, err := scenario.CreatePreAuthKeyWithTags(
		userMap["server"].GetId(), false, false, []string{"tag:server-a"},
	)
	require.NoError(t, err)
	err = serverA.Login(headscale.GetEndpoint(), pakServerA.GetKey())
	require.NoError(t, err)
	err = serverA.WaitForRunning(30 * time.Second)
	require.NoError(t, err)

	// Connect Server A to externet AFTER login to avoid link change race
	// (adding a network interface restarts tailscaled's connection).
	err = dockertestutil.AddContainerToNetwork(scenario.Pool(), externet, serverA.Hostname())
	require.NoError(t, err, "failed to connect Server A to externet")

	// Create Server B (tag:server-b) on usernet1.
	serverB, err := scenario.CreateTailscaleNode("head",
		tsic.WithNetwork(usernet1),
		tsic.WithAcceptRoutes(),
	)
	require.NoError(t, err)

	defer func() { _, _, _ = serverB.Shutdown() }()

	pakServerB, err := scenario.CreatePreAuthKeyWithTags(
		userMap["server"].GetId(), false, false, []string{"tag:server-b"},
	)
	require.NoError(t, err)
	err = serverB.Login(headscale.GetEndpoint(), pakServerB.GetKey())
	require.NoError(t, err)
	err = serverB.WaitForRunning(30 * time.Second)
	require.NoError(t, err)

	// Connect Server B to externet AFTER login.
	err = dockertestutil.AddContainerToNetwork(scenario.Pool(), externet, serverB.Hostname())
	require.NoError(t, err, "failed to connect Server B to externet")

	// Create Client A (tag:group-a) on usernet2.
	clientA, err := scenario.CreateTailscaleNode("head",
		tsic.WithNetwork(usernet2),
		tsic.WithAcceptRoutes(),
	)
	require.NoError(t, err)

	defer func() { _, _, _ = clientA.Shutdown() }()

	pakClientA, err := scenario.CreatePreAuthKeyWithTags(
		userMap["client"].GetId(), false, false, []string{"tag:group-a"},
	)
	require.NoError(t, err)
	err = clientA.Login(headscale.GetEndpoint(), pakClientA.GetKey())
	require.NoError(t, err)
	err = clientA.WaitForRunning(30 * time.Second)
	require.NoError(t, err)

	// Create Client B (tag:group-b) on usernet2.
	clientB, err := scenario.CreateTailscaleNode("head",
		tsic.WithNetwork(usernet2),
		tsic.WithAcceptRoutes(),
	)
	require.NoError(t, err)

	defer func() { _, _, _ = clientB.Shutdown() }()

	pakClientB, err := scenario.CreatePreAuthKeyWithTags(
		userMap["client"].GetId(), false, false, []string{"tag:group-b"},
	)
	require.NoError(t, err)
	err = clientB.Login(headscale.GetEndpoint(), pakClientB.GetKey())
	require.NoError(t, err)
	err = clientB.WaitForRunning(30 * time.Second)
	require.NoError(t, err)

	// Wait for all peers to see each other (4 nodes, each sees 3 peers).
	allNodes := []TailscaleClient{serverA, serverB, clientA, clientB}
	for _, node := range allNodes {
		err = node.WaitForPeers(len(allNodes)-1, 60*time.Second, 1*time.Second)
		require.NoErrorf(t, err, "node %s failed to see all peers", node.Hostname())
	}

	// Both servers advertise subnet + exit routes.
	for _, server := range []TailscaleClient{serverA, serverB} {
		command := []string{
			"tailscale", "set",
			"--advertise-routes=" + route.String(),
			"--advertise-exit-node",
		}
		_, _, err = server.Execute(command)
		require.NoErrorf(t, err, "failed to advertise routes on %s", server.Hostname())
	}

	// Wait for auto-approval: 1 subnet + 2 exit = 3 announced, 3 approved per server.
	// Primary election is global, so subnet count may differ between servers.
	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		nodes, err := headscale.ListNodes()
		assert.NoError(c, err)

		serverANode := MustFindNode(serverA.Hostname(), nodes)
		t.Logf("Server A %s: announced=%v, approved=%v, subnet=%v",
			serverANode.GetName(),
			serverANode.GetAvailableRoutes(),
			serverANode.GetApprovedRoutes(),
			serverANode.GetSubnetRoutes())
		assert.Len(c, serverANode.GetAvailableRoutes(), 3, "Server A should have 3 announced routes")
		assert.Len(c, serverANode.GetApprovedRoutes(), 3, "Server A should have 3 approved routes")

		serverBNode := MustFindNode(serverB.Hostname(), nodes)
		t.Logf("Server B %s: announced=%v, approved=%v, subnet=%v",
			serverBNode.GetName(),
			serverBNode.GetAvailableRoutes(),
			serverBNode.GetApprovedRoutes(),
			serverBNode.GetSubnetRoutes())
		assert.Len(c, serverBNode.GetAvailableRoutes(), 3, "Server B should have 3 announced routes")
		assert.Len(c, serverBNode.GetApprovedRoutes(), 3, "Server B should have 3 approved routes")
	}, assertTimeout, 500*time.Millisecond, "Both servers should have auto-approved subnet + exit routes")

	// Get webservice info.
	services, err := scenario.Services("usernet1")
	require.NoError(t, err)
	require.Len(t, services, 1)

	web := services[0]
	webip := netip.MustParseAddr(web.GetIPInNetwork(usernet1))
	weburl := fmt.Sprintf("http://%s/etc/hostname", webip)
	t.Logf("webservice: %s, %s", webip.String(), weburl)

	// Get externet webservice (exit-only destination, not covered by subnet route).
	externetServices, err := scenario.Services("externet")
	require.NoError(t, err)
	require.Len(t, externetServices, 1)

	extWeb := externetServices[0]
	extWebIP := netip.MustParseAddr(extWeb.GetIPInNetwork(externet))
	extWebURL := fmt.Sprintf("http://%s/etc/hostname", extWebIP)
	t.Logf("externet webservice: %s, %s", extWebIP.String(), extWebURL)

	serverAID := serverA.MustID()
	serverBID := serverB.MustID()

	// Verify Client A sees Server A's subnet route but NOT Server B's.
	// (subnet via steering: group-a -> server-a)
	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		status, err := clientA.Status()
		assert.NoError(c, err)

		for _, peerKey := range status.Peers() {
			peerStatus := status.Peer[peerKey]

			switch peerStatus.ID {
			case serverAID.StableID():
				t.Logf("Client A sees Server A: AllowedIPs=%v, PrimaryRoutes=%v",
					peerStatus.AllowedIPs, peerStatus.PrimaryRoutes)
				requirePeerSubnetRoutesWithCollect(c, peerStatus, []netip.Prefix{*route})
			case serverBID.StableID():
				t.Logf("Client A sees Server B: AllowedIPs=%v, PrimaryRoutes=%v",
					peerStatus.AllowedIPs, peerStatus.PrimaryRoutes)
				// Server B should only show exit routes to Client A, not the subnet.
				got := filterNonRoutes(peerStatus)
				for _, r := range got {
					assert.True(c, tsaddr.IsExitRoute(r),
						"Client A should not see Server B's subnet route, got %s", r)
				}
			}
		}
	}, assertTimeout, 500*time.Millisecond, "Client A should see subnet route only via Server A")

	// Verify Client B sees Server B's subnet route but NOT Server A's.
	// (subnet via steering: group-b -> server-b)
	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		status, err := clientB.Status()
		assert.NoError(c, err)

		for _, peerKey := range status.Peers() {
			peerStatus := status.Peer[peerKey]

			switch peerStatus.ID {
			case serverBID.StableID():
				t.Logf("Client B sees Server B: AllowedIPs=%v, PrimaryRoutes=%v",
					peerStatus.AllowedIPs, peerStatus.PrimaryRoutes)
				requirePeerSubnetRoutesWithCollect(c, peerStatus, []netip.Prefix{*route})
			case serverAID.StableID():
				t.Logf("Client B sees Server A: AllowedIPs=%v, PrimaryRoutes=%v",
					peerStatus.AllowedIPs, peerStatus.PrimaryRoutes)
				// Server A should only show exit routes to Client B, not the subnet.
				got := filterNonRoutes(peerStatus)
				for _, r := range got {
					assert.True(c, tsaddr.IsExitRoute(r),
						"Client B should not see Server A's subnet route, got %s", r)
				}
			}
		}
	}, assertTimeout, 500*time.Millisecond, "Client B should see subnet route only via Server B")

	// Verify subnet route steering: Client A reaches webservice through Server A.
	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		result, err := clientA.Curl(weburl)
		assert.NoError(c, err)
		assert.Len(c, result, 13)
	}, assertTimeout, 200*time.Millisecond, "Client A should reach webservice")

	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		tr, err := clientA.Traceroute(webip)
		assert.NoError(c, err)

		ip, err := serverA.IPv4()
		if !assert.NoError(c, err, "failed to get IPv4 for serverA") {
			return
		}

		assertTracerouteViaIPWithCollect(c, tr, ip)
	}, assertTimeout, 200*time.Millisecond, "Client A subnet traceroute should go through Server A")

	// Verify subnet route steering: Client B reaches webservice through Server B.
	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		result, err := clientB.Curl(weburl)
		assert.NoError(c, err)
		assert.Len(c, result, 13)
	}, assertTimeout, 200*time.Millisecond, "Client B should reach webservice")

	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		tr, err := clientB.Traceroute(webip)
		assert.NoError(c, err)

		ip, err := serverB.IPv4()
		if !assert.NoError(c, err, "failed to get IPv4 for serverB") {
			return
		}

		assertTracerouteViaIPWithCollect(c, tr, ip)
	}, assertTimeout, 200*time.Millisecond, "Client B subnet traceroute should go through Server B")

	// Via exit steering: Client A should see exit routes ONLY on Server B (crossed).
	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		status, err := clientA.Status()
		assert.NoError(c, err)

		for _, peerKey := range status.Peers() {
			peerStatus := status.Peer[peerKey]

			switch peerStatus.ID {
			case serverBID.StableID():
				// Client A should see Server B's exit routes (via steers exit to server-b).
				t.Logf("Client A sees Server B: AllowedIPs=%v", peerStatus.AllowedIPs)
				got := filterNonRoutes(peerStatus)
				hasExit := slices.ContainsFunc(got, tsaddr.IsExitRoute)
				assert.True(c, hasExit, "Client A should see Server B's exit routes")
			case serverAID.StableID():
				// Client A should NOT see Server A's exit routes (only subnet).
				t.Logf("Client A sees Server A: AllowedIPs=%v", peerStatus.AllowedIPs)

				got := filterNonRoutes(peerStatus)
				for _, r := range got {
					assert.False(c, tsaddr.IsExitRoute(r),
						"Client A should NOT see Server A's exit routes, got %s", r)
				}
			}
		}
	}, assertTimeout, 500*time.Millisecond, "Client A should see exit routes only via Server B")

	// Via exit steering: Client B should see exit routes ONLY on Server A (crossed).
	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		status, err := clientB.Status()
		assert.NoError(c, err)

		for _, peerKey := range status.Peers() {
			peerStatus := status.Peer[peerKey]

			switch peerStatus.ID {
			case serverAID.StableID():
				// Client B should see Server A's exit routes (via steers exit to server-a).
				t.Logf("Client B sees Server A: AllowedIPs=%v", peerStatus.AllowedIPs)
				got := filterNonRoutes(peerStatus)
				hasExit := slices.ContainsFunc(got, tsaddr.IsExitRoute)
				assert.True(c, hasExit, "Client B should see Server A's exit routes")
			case serverBID.StableID():
				// Client B should NOT see Server B's exit routes (only subnet).
				t.Logf("Client B sees Server B: AllowedIPs=%v", peerStatus.AllowedIPs)

				got := filterNonRoutes(peerStatus)
				for _, r := range got {
					assert.False(c, tsaddr.IsExitRoute(r),
						"Client B should NOT see Server B's exit routes, got %s", r)
				}
			}
		}
	}, assertTimeout, 500*time.Millisecond, "Client B should see exit routes only via Server A")

	// Select the via-designated exit nodes, then validate traffic.
	// Client A -> Server B (via steered), Client B -> Server A (via steered).
	serverBStatus := serverB.MustStatus()
	commandExitA := []string{
		"tailscale", "set",
		"--exit-node=" + serverBStatus.Self.DNSName,
	}
	_, _, err = clientA.Execute(commandExitA)
	require.NoError(t, err, "Client A failed to set exit node to Server B")

	serverAStatus := serverA.MustStatus()
	commandExitB := []string{
		"tailscale", "set",
		"--exit-node=" + serverAStatus.Self.DNSName,
	}
	_, _, err = clientB.Execute(commandExitB)
	require.NoError(t, err, "Client B failed to set exit node to Server A")

	// Subnet traffic should still go through the subnet router (takes priority).
	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		result, err := clientA.Curl(weburl)
		assert.NoError(c, err)
		assert.Len(c, result, 13)
	}, assertTimeout, 200*time.Millisecond, "Client A should reach subnet webservice")

	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		tr, err := clientA.Traceroute(webip)
		assert.NoError(c, err)

		ip, err := serverA.IPv4()
		if !assert.NoError(c, err, "failed to get IPv4 for serverA") {
			return
		}

		assertTracerouteViaIPWithCollect(c, tr, ip)
	}, assertTimeout, 200*time.Millisecond, "Client A subnet traffic should go through Server A (not exit node)")

	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		result, err := clientB.Curl(weburl)
		assert.NoError(c, err)
		assert.Len(c, result, 13)
	}, assertTimeout, 200*time.Millisecond, "Client B should reach subnet webservice")

	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		tr, err := clientB.Traceroute(webip)
		assert.NoError(c, err)

		ip, err := serverB.IPv4()
		if !assert.NoError(c, err, "failed to get IPv4 for serverB") {
			return
		}

		assertTracerouteViaIPWithCollect(c, tr, ip)
	}, assertTimeout, 200*time.Millisecond, "Client B subnet traffic should go through Server B (not exit node)")

	// Exit traffic to externet (not covered by subnet route) goes through exit node.
	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		result, err := clientA.Curl(extWebURL)
		assert.NoError(c, err)
		assert.Len(c, result, 13)
	}, assertTimeout, 200*time.Millisecond, "Client A should reach externet via exit node")

	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		tr, err := clientA.Traceroute(extWebIP)
		assert.NoError(c, err)

		ip, err := serverB.IPv4()
		if !assert.NoError(c, err, "failed to get IPv4 for serverB") {
			return
		}

		assertTracerouteViaIPWithCollect(c, tr, ip)
	}, assertTimeout, 200*time.Millisecond, "Client A exit traffic should go through Server B")

	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		result, err := clientB.Curl(extWebURL)
		assert.NoError(c, err)
		assert.Len(c, result, 13)
	}, assertTimeout, 200*time.Millisecond, "Client B should reach externet via exit node")

	assert.EventuallyWithT(t, func(c *assert.CollectT) {
		tr, err := clientB.Traceroute(extWebIP)
		assert.NoError(c, err)

		ip, err := serverA.IPv4()
		if !assert.NoError(c, err, "failed to get IPv4 for serverA") {
			return
		}

		assertTracerouteViaIPWithCollect(c, tr, ip)
	}, assertTimeout, 200*time.Millisecond, "Client B exit traffic should go through Server A")
}