policy/v2: use approved node routes in wildcard SrcIPs

Per Tailscale documentation, the wildcard (*) source includes "any
approved subnets" — the actually-advertised-and-approved routes from
nodes, not the autoApprover policy prefixes.

Change Asterix.resolve() to return just the base CGNAT+ULA set, and
add approved subnet routes as separate SrcIPs entries in the filter
compilation path. This preserves individual route prefixes that would
otherwise be merged by IPSet (e.g., 10.0.0.0/8 absorbing 10.33.0.0/16).

Also swap rule ordering in compileGrantWithAutogroupSelf() to emit
non-self destination rules before autogroup:self rules, matching the
Tailscale FilterRule wire format ordering.

Remove the unused AutoApproverPolicy.prefixes() method.

Updates #2180

hscontrol/policy/v2/filter.go

@@ -21,6 +21,34 @@ var (
 	errSelfInSources = errors.New("autogroup:self cannot be used in sources")
 )
 
+// sourcesHaveWildcard returns true if any of the source aliases is
+// a wildcard (*). Used to determine whether approved subnet routes
+// should be appended to SrcIPs.
+func sourcesHaveWildcard(srcs Aliases) bool {
+	for _, src := range srcs {
+		if _, ok := src.(Asterix); ok {
+			return true
+		}
+	}
+
+	return false
+}
+
+// srcIPsWithRoutes returns the SrcIPs string slice, appending
+// approved subnet routes when the sources include a wildcard.
+func srcIPsWithRoutes(
+	resolved ResolvedAddresses,
+	hasWildcard bool,
+	nodes views.Slice[types.NodeView],
+) []string {
+	ips := resolved.Strings()
+	if hasWildcard {
+		ips = append(ips, approvedSubnetRoutes(nodes)...)
+	}
+
+	return ips
+}
+
 // compileFilterRules takes a set of nodes and an ACLPolicy and generates a
 // set of Tailscale compatible FilterRules used to allow traffic on clients.
 func (pol *Policy) compileFilterRules(
@@ -48,12 +76,14 @@ func (pol *Policy) compileFilterRules(
 			continue
 		}
 
+		hasWildcard := sourcesHaveWildcard(grant.Sources)
+
 		for _, ipp := range grant.InternetProtocols {
 			destPorts := pol.destinationsToNetPortRange(users, nodes, grant.Destinations, ipp.Ports)
 
 			if len(destPorts) > 0 {
 				rules = append(rules, tailcfg.FilterRule{
-					SrcIPs:   srcIPs.Strings(),
+					SrcIPs:   srcIPsWithRoutes(srcIPs, hasWildcard, nodes),
 					DstPorts: destPorts,
 					IPProto:  ipp.Protocol.toIANAProtocolNumbers(),
 				})
@@ -76,7 +106,7 @@ func (pol *Policy) compileFilterRules(
 			}
 
 			rules = append(rules, tailcfg.FilterRule{
-				SrcIPs:   srcIPs.Strings(),
+				SrcIPs:   srcIPsWithRoutes(srcIPs, hasWildcard, nodes),
 				CapGrant: capGrants,
 			})
 		}
@@ -222,7 +252,38 @@ func (pol *Policy) compileGrantWithAutogroupSelf(
 		return rules, nil
 	}
 
+	hasWildcard := sourcesHaveWildcard(grant.Sources)
+
 	for _, ipp := range grant.InternetProtocols {
+		// Handle non-self destinations first to match Tailscale's
+		// rule ordering in the FilterRule wire format.
+		if len(otherDests) > 0 {
+			var srcIPs netipx.IPSetBuilder
+
+			for _, ips := range resolvedSrcs {
+				for _, pref := range ips.Prefixes() {
+					srcIPs.AddPrefix(pref)
+				}
+			}
+
+			srcResolved, err := newResolved(&srcIPs)
+			if err != nil {
+				return nil, err
+			}
+
+			if !srcResolved.Empty() {
+				destPorts := pol.destinationsToNetPortRange(users, nodes, otherDests, ipp.Ports)
+
+				if len(destPorts) > 0 {
+					rules = append(rules, tailcfg.FilterRule{
+						SrcIPs:   srcIPsWithRoutes(srcResolved, hasWildcard, nodes),
+						DstPorts: destPorts,
+						IPProto:  ipp.Protocol.toIANAProtocolNumbers(),
+					})
+				}
+			}
+		}
+
 		// Handle autogroup:self destinations (if any)
 		// Tagged nodes don't participate in autogroup:self (identity is tag-based, not user-based)
 		if len(autogroupSelfDests) > 0 && !node.IsTagged() {
@@ -277,33 +338,6 @@ func (pol *Policy) compileGrantWithAutogroupSelf(
 				}
 			}
 		}
-
-		if len(otherDests) > 0 {
-			var srcIPs netipx.IPSetBuilder
-
-			for _, ips := range resolvedSrcs {
-				for _, pref := range ips.Prefixes() {
-					srcIPs.AddPrefix(pref)
-				}
-			}
-
-			srcResolved, err := newResolved(&srcIPs)
-			if err != nil {
-				return nil, err
-			}
-
-			if !srcResolved.Empty() {
-				destPorts := pol.destinationsToNetPortRange(users, nodes, otherDests, ipp.Ports)
-
-				if len(destPorts) > 0 {
-					rules = append(rules, tailcfg.FilterRule{
-						SrcIPs:   srcResolved.Strings(),
-						DstPorts: destPorts,
-						IPProto:  ipp.Protocol.toIANAProtocolNumbers(),
-					})
-				}
-			}
-		}
 	}
 
 	return rules, nil

hscontrol/policy/v2/tailscale_acl_data_compat_test.go

@@ -89,7 +89,11 @@ func setupACLCompatNodes(users types.Users) types.Nodes {
 		{
 			ID: 7, GivenName: "subnet-router",
 			IPv4: ptrAddr("100.92.142.61"), IPv6: ptrAddr("fd7a:115c:a1e0::3e37:8e3d"),
-			Tags: []string{"tag:router"}, Hostinfo: &tailcfg.Hostinfo{},
+			Tags: []string{"tag:router"},
+			Hostinfo: &tailcfg.Hostinfo{
+				RoutableIPs: []netip.Prefix{netip.MustParsePrefix("10.33.0.0/16")},
+			},
+			ApprovedRoutes: []netip.Prefix{netip.MustParsePrefix("10.33.0.0/16")},
 		},
 		{
 			ID: 8, GivenName: "exit-node",
@@ -146,11 +150,13 @@ type aclTestFile struct {
 	} `json:"input"`
 	Topology struct {
 		Nodes map[string]struct {
-			Hostname string   `json:"hostname"`
-			Tags     []string `json:"tags"`
-			IPv4     string   `json:"ipv4"`
-			IPv6     string   `json:"ipv6"`
-			User     string   `json:"user"`
+			Hostname       string   `json:"hostname"`
+			Tags           []string `json:"tags"`
+			IPv4           string   `json:"ipv4"`
+			IPv6           string   `json:"ipv6"`
+			User           string   `json:"user"`
+			RoutableIPs    []string `json:"routable_ips"`
+			ApprovedRoutes []string `json:"approved_routes"`
 		} `json:"nodes"`
 	} `json:"topology"`
 	Captures map[string]struct {

hscontrol/policy/v2/tailscale_grants_compat_test.go

@@ -20,6 +20,7 @@ package v2
 
 import (
 	"encoding/json"
+	"net/netip"
 	"os"
 	"path/filepath"
 	"strings"
@@ -136,7 +137,10 @@ func setupGrantsCompatNodes(users types.Users) types.Nodes {
 		IPv4:      ptrAddr("100.92.142.61"),
 		IPv6:      ptrAddr("fd7a:115c:a1e0::3e37:8e3d"),
 		Tags:      []string{"tag:router"},
-		Hostinfo:  &tailcfg.Hostinfo{},
+		Hostinfo: &tailcfg.Hostinfo{
+			RoutableIPs: []netip.Prefix{netip.MustParsePrefix("10.33.0.0/16")},
+		},
+		ApprovedRoutes: []netip.Prefix{netip.MustParsePrefix("10.33.0.0/16")},
 	}
 
 	nodeExitNode := &types.Node{

hscontrol/policy/v2/types.go

@@ -296,19 +296,33 @@ func (a Asterix) Resolve(p *Policy, u types.Users, n views.Slice[types.NodeView]
 	return newResolvedAddresses(a.resolve(p, u, n))
 }
 
-func (a Asterix) resolve(p *Policy, _ types.Users, _ views.Slice[types.NodeView]) (*netipx.IPSet, error) {
-	if p != nil && len(p.AutoApprovers.prefixes()) > 0 {
-		var ipb netipx.IPSetBuilder
-		ipb.AddSet(asterixResolved())
+func (a Asterix) resolve(_ *Policy, _ types.Users, _ views.Slice[types.NodeView]) (*netipx.IPSet, error) {
+	return asterixResolved(), nil
+}
 
-		for _, pfx := range p.AutoApprovers.prefixes() {
-			ipb.AddPrefix(pfx)
+// approvedSubnetRoutes collects all approved non-exit subnet routes
+// advertised across all nodes. Per Tailscale documentation, wildcard
+// (*) SrcIPs include "any approved subnets".
+//
+// These are collected separately from the Asterix IPSet because
+// IPSet merges overlapping ranges (e.g. 10.0.0.0/8 absorbs
+// 10.33.0.0/16), but Tailscale preserves individual route entries.
+func approvedSubnetRoutes(nodes views.Slice[types.NodeView]) []string {
+	seen := make(map[string]bool)
+
+	var routes []string
+
+	for _, node := range nodes.All() {
+		for _, route := range node.SubnetRoutes() {
+			s := route.String()
+			if !seen[s] {
+				seen[s] = true
+				routes = append(routes, s)
+			}
 		}
-
-		return ipb.IPSet()
 	}
 
-	return asterixResolved(), nil
+	return routes
 }
 
 // Username is a string that represents a username, it must contain an @.
@@ -1481,22 +1495,6 @@ func (ap AutoApproverPolicy) MarshalJSON() ([]byte, error) {
 	return json.Marshal(&obj)
 }
 
-// prefixes returns the prefixes that have auto-approvers defined in the policy.
-// It filters out exit routes since they are not associated with a specific prefix and are handled separately.
-func (ap AutoApproverPolicy) prefixes() []netip.Prefix {
-	prefixes := make([]netip.Prefix, 0, len(ap.Routes))
-
-	for prefix := range ap.Routes {
-		if tsaddr.IsExitRoute(prefix) {
-			continue
-		}
-
-		prefixes = append(prefixes, prefix)
-	}
-
-	return prefixes
-}
-
 // resolveAutoApprovers resolves the AutoApprovers to a map of netip.Prefix to netipx.IPSet.
 // The resulting map can be used to quickly look up if a node can self-approve a route.
 // It is intended for internal use in a PolicyManager.