simplify expandAlias function, move seperate logic out

Signed-off-by: Kristoffer Dalby <kristoffer@tailscale.com>

acls.go

@@ -338,9 +338,8 @@ func (h *Headscale) generateSSHRules() ([]*tailcfg.SSHRule, error) {
 
 		principals := make([]*tailcfg.SSHPrincipal, 0, len(sshACL.Sources))
 		for innerIndex, rawSrc := range sshACL.Sources {
-			expandedSrcs, err := expandAlias(
+			expandedSrcs, err := h.aclPolicy.expandAlias(
 				machines,
-				*h.aclPolicy,
 				rawSrc,
 				h.cfg.OIDC.StripEmaildomain,
 			)
@@ -391,16 +390,16 @@ func sshCheckAction(duration string) (*tailcfg.SSHAction, error) {
 
 func generateACLPolicySrc(
 	machines []Machine,
-	aclPolicy ACLPolicy,
+	pol ACLPolicy,
 	src string,
 	stripEmaildomain bool,
 ) ([]string, error) {
-	return expandAlias(machines, aclPolicy, src, stripEmaildomain)
+	return pol.expandAlias(machines, src, stripEmaildomain)
 }
 
 func generateACLPolicyDest(
 	machines []Machine,
-	aclPolicy ACLPolicy,
+	pol ACLPolicy,
 	dest string,
 	needsWildcard bool,
 	stripEmaildomain bool,
@@ -448,9 +447,8 @@ func generateACLPolicyDest(
 		alias = fmt.Sprintf("%s:%s", tokens[0], tokens[1])
 	}
 
-	expanded, err := expandAlias(
+	expanded, err := pol.expandAlias(
 		machines,
-		aclPolicy,
 		alias,
 		stripEmaildomain,
 	)
@@ -534,13 +532,11 @@ func parseProtocol(protocol string) ([]int, bool, error) {
 // - an ip
 // - a cidr
 // and transform these in IPAddresses.
-func expandAlias(
+func (pol *ACLPolicy) expandAlias(
 	machines Machines,
-	aclPolicy ACLPolicy,
 	alias string,
 	stripEmailDomain bool,
 ) ([]string, error) {
-	ips := []string{}
 	if alias == "*" {
 		return []string{"*"}, nil
 	}
@@ -549,120 +545,48 @@ func expandAlias(
 		Str("alias", alias).
 		Msg("Expanding")
 
+	// if alias is a group
 	if strings.HasPrefix(alias, "group:") {
-		users, err := expandGroup(aclPolicy, alias, stripEmailDomain)
+		return pol.getIPsFromGroup(alias, machines, stripEmailDomain)
-		if err != nil {
-			return ips, err
-		}
-		for _, n := range users {
-			nodes := filterMachinesByUser(machines, n)
-			for _, node := range nodes {
-				ips = append(ips, node.IPAddresses.ToStringSlice()...)
-			}
-		}
-
-		return ips, nil
 	}
 
+	// if alias is a tag
 	if strings.HasPrefix(alias, "tag:") {
-		// check for forced tags
+		return pol.getIPsFromTag(alias, machines, stripEmailDomain)
-		for _, machine := range machines {
-			if contains(machine.ForcedTags, alias) {
-				ips = append(ips, machine.IPAddresses.ToStringSlice()...)
-			}
-		}
-
-		// find tag owners
-		owners, err := expandTagOwners(aclPolicy, alias, stripEmailDomain)
-		if err != nil {
-			if errors.Is(err, errInvalidTag) {
-				if len(ips) == 0 {
-					return ips, fmt.Errorf(
-						"%w. %v isn't owned by a TagOwner and no forced tags are defined",
-						errInvalidTag,
-						alias,
-					)
-				}
-
-				return ips, nil
-			} else {
-				return ips, err
-			}
-		}
-
-		// filter out machines per tag owner
-		for _, user := range owners {
-			machines := filterMachinesByUser(machines, user)
-			for _, machine := range machines {
-				hi := machine.GetHostInfo()
-				if contains(hi.RequestTags, alias) {
-					ips = append(ips, machine.IPAddresses.ToStringSlice()...)
-				}
-			}
-		}
-
-		return ips, nil
 	}
 
 	// if alias is a user
-	nodes := filterMachinesByUser(machines, alias)
+	if ips := pol.getIPsForUser(alias, machines, stripEmailDomain); len(ips) > 0 {
-	nodes = excludeCorrectlyTaggedNodes(aclPolicy, nodes, alias, stripEmailDomain)
-
-	for _, n := range nodes {
-		ips = append(ips, n.IPAddresses.ToStringSlice()...)
-	}
-	if len(ips) > 0 {
 		return ips, nil
 	}
 
 	// if alias is an host
-	if h, ok := aclPolicy.Hosts[alias]; ok {
+	if h, ok := pol.Hosts[alias]; ok {
 		log.Trace().Str("host", h.String()).Msg("expandAlias got hosts entry")
 
-		return expandAlias(machines, aclPolicy, h.String(), stripEmailDomain)
+		return pol.expandAlias(machines, h.String(), stripEmailDomain)
 	}
 
 	// if alias is an IP
 	if ip, err := netip.ParseAddr(alias); err == nil {
-		log.Trace().Str("ip", ip.String()).Msg("expandAlias got ip")
+		return pol.getIPsFromSingleIP(ip, machines)
-		ips := []string{ip.String()}
-		matches := machines.FilterByIP(ip)
-
-		for _, machine := range matches {
-			ips = append(ips, machine.IPAddresses.ToStringSlice()...)
 	}
 
-		return lo.Uniq(ips), nil
+	// if alias is an IP Prefix (CIDR)
-	}
+	if prefix, err := netip.ParsePrefix(alias); err == nil {
-
+		return pol.getIPsFromIPPrefix(prefix, machines)
-	if cidr, err := netip.ParsePrefix(alias); err == nil {
-		log.Trace().Str("cidr", cidr.String()).Msg("expandAlias got cidr")
-		val := []string{cidr.String()}
-		// This is suboptimal and quite expensive, but if we only add the cidr, we will miss all the relevant IPv6
-		// addresses for the hosts that belong to tailscale. This doesnt really affect stuff like subnet routers.
-		for _, machine := range machines {
-			for _, ip := range machine.IPAddresses {
-				// log.Trace().
-				// 	Msgf("checking if machine ip (%s) is part of cidr (%s): %v, is single ip cidr (%v), addr: %s", ip.String(), cidr.String(), cidr.Contains(ip), cidr.IsSingleIP(), cidr.Addr().String())
-				if cidr.Contains(ip) {
-					val = append(val, machine.IPAddresses.ToStringSlice()...)
-				}
-			}
-		}
-
-		return lo.Uniq(val), nil
 	}
 
 	log.Warn().Msgf("No IPs found with the alias %v", alias)
 
-	return ips, nil
+	return []string{}, nil
 }
 
 // excludeCorrectlyTaggedNodes will remove from the list of input nodes the ones
 // that are correctly tagged since they should not be listed as being in the user
 // we assume in this function that we only have nodes from 1 user.
 func excludeCorrectlyTaggedNodes(
-	aclPolicy ACLPolicy,
+	aclPolicy *ACLPolicy,
 	nodes []Machine,
 	user string,
 	stripEmailDomain bool,
@@ -670,7 +594,7 @@ func excludeCorrectlyTaggedNodes(
 	out := []Machine{}
 	tags := []string{}
 	for tag := range aclPolicy.TagOwners {
-		owners, _ := expandTagOwners(aclPolicy, user, stripEmailDomain)
+		owners, _ := getTagOwners(aclPolicy, user, stripEmailDomain)
 		ns := append(owners, user)
 		if contains(ns, user) {
 			tags = append(tags, tag)
@@ -758,15 +682,15 @@ func filterMachinesByUser(machines []Machine, user string) []Machine {
 	return out
 }
 
-// expandTagOwners will return a list of user. An owner can be either a user or a group
+// getTagOwners will return a list of user. An owner can be either a user or a group
 // a group cannot be composed of groups.
-func expandTagOwners(
+func getTagOwners(
-	aclPolicy ACLPolicy,
+	pol *ACLPolicy,
 	tag string,
 	stripEmailDomain bool,
 ) ([]string, error) {
 	var owners []string
-	ows, ok := aclPolicy.TagOwners[tag]
+	ows, ok := pol.TagOwners[tag]
 	if !ok {
 		return []string{}, fmt.Errorf(
 			"%w. %v isn't owned by a TagOwner. Please add one first. https://tailscale.com/kb/1018/acls/#tag-owners",
@@ -776,7 +700,7 @@ func expandTagOwners(
 	}
 	for _, owner := range ows {
 		if strings.HasPrefix(owner, "group:") {
-			gs, err := expandGroup(aclPolicy, owner, stripEmailDomain)
+			gs, err := pol.getUsersInGroup(owner, stripEmailDomain)
 			if err != nil {
 				return []string{}, err
 			}
@@ -789,15 +713,15 @@ func expandTagOwners(
 	return owners, nil
 }
 
-// expandGroup will return the list of user inside the group
+// getUsersInGroup will return the list of user inside the group
 // after some validation.
-func expandGroup(
+func (pol *ACLPolicy) getUsersInGroup(
-	aclPolicy ACLPolicy,
 	group string,
 	stripEmailDomain bool,
 ) ([]string, error) {
-	outGroups := []string{}
+	users := []string{}
-	aclGroups, ok := aclPolicy.Groups[group]
+	log.Trace().Caller().Interface("pol", pol).Msg("test")
+	aclGroups, ok := pol.Groups[group]
 	if !ok {
 		return []string{}, fmt.Errorf(
 			"group %v isn't registered. %w",
@@ -820,8 +744,129 @@ func expandGroup(
 				errInvalidGroup,
 			)
 		}
-		outGroups = append(outGroups, grp)
+		users = append(users, grp)
 	}
 
-	return outGroups, nil
+	return users, nil
+}
+
+func (pol *ACLPolicy) getIPsFromGroup(
+	group string,
+	machines Machines,
+	stripEmailDomain bool,
+) ([]string, error) {
+	ips := []string{}
+
+	users, err := pol.getUsersInGroup(group, stripEmailDomain)
+	if err != nil {
+		return ips, err
+	}
+	for _, n := range users {
+		nodes := filterMachinesByUser(machines, n)
+		for _, node := range nodes {
+			ips = append(ips, node.IPAddresses.ToStringSlice()...)
+		}
+	}
+
+	return ips, nil
+}
+
+func (pol *ACLPolicy) getIPsFromTag(
+	alias string,
+	machines Machines,
+	stripEmailDomain bool,
+) ([]string, error) {
+	ips := []string{}
+
+	// check for forced tags
+	for _, machine := range machines {
+		if contains(machine.ForcedTags, alias) {
+			ips = append(ips, machine.IPAddresses.ToStringSlice()...)
+		}
+	}
+
+	// find tag owners
+	owners, err := getTagOwners(pol, alias, stripEmailDomain)
+	if err != nil {
+		if errors.Is(err, errInvalidTag) {
+			if len(ips) == 0 {
+				return ips, fmt.Errorf(
+					"%w. %v isn't owned by a TagOwner and no forced tags are defined",
+					errInvalidTag,
+					alias,
+				)
+			}
+
+			return ips, nil
+		} else {
+			return ips, err
+		}
+	}
+
+	// filter out machines per tag owner
+	for _, user := range owners {
+		machines := filterMachinesByUser(machines, user)
+		for _, machine := range machines {
+			hi := machine.GetHostInfo()
+			if contains(hi.RequestTags, alias) {
+				ips = append(ips, machine.IPAddresses.ToStringSlice()...)
+			}
+		}
+	}
+
+	return ips, nil
+}
+
+func (pol *ACLPolicy) getIPsForUser(
+	user string,
+	machines Machines,
+	stripEmailDomain bool,
+) []string {
+	ips := []string{}
+
+	nodes := filterMachinesByUser(machines, user)
+	nodes = excludeCorrectlyTaggedNodes(pol, nodes, user, stripEmailDomain)
+
+	for _, n := range nodes {
+		ips = append(ips, n.IPAddresses.ToStringSlice()...)
+	}
+
+	return ips
+}
+
+func (pol *ACLPolicy) getIPsFromSingleIP(
+	ip netip.Addr,
+	machines Machines,
+) ([]string, error) {
+	log.Trace().Str("ip", ip.String()).Msg("expandAlias got ip")
+
+	ips := []string{ip.String()}
+	matches := machines.FilterByIP(ip)
+
+	for _, machine := range matches {
+		ips = append(ips, machine.IPAddresses.ToStringSlice()...)
+	}
+
+	return lo.Uniq(ips), nil
+}
+
+func (pol *ACLPolicy) getIPsFromIPPrefix(
+	prefix netip.Prefix,
+	machines Machines,
+) ([]string, error) {
+	log.Trace().Str("prefix", prefix.String()).Msg("expandAlias got prefix")
+	val := []string{prefix.String()}
+	// This is suboptimal and quite expensive, but if we only add the prefix, we will miss all the relevant IPv6
+	// addresses for the hosts that belong to tailscale. This doesnt really affect stuff like subnet routers.
+	for _, machine := range machines {
+		for _, ip := range machine.IPAddresses {
+			// log.Trace().
+			// 	Msgf("checking if machine ip (%s) is part of prefix (%s): %v, is single ip prefix (%v), addr: %s", ip.String(), prefix.String(), prefix.Contains(ip), prefix.IsSingleIP(), prefix.Addr().String())
+			if prefix.Contains(ip) {
+				val = append(val, machine.IPAddresses.ToStringSlice()...)
+			}
+		}
+	}
+
+	return lo.Uniq(val), nil
 }

acls_test.go

@@ -556,26 +556,31 @@ func (s *Suite) TestPortGroup(c *check.C) {
 }
 
 func Test_expandGroup(t *testing.T) {
+	type field struct {
+		pol ACLPolicy
+	}
 	type args struct {
-		aclPolicy        ACLPolicy
 		group            string
 		stripEmailDomain bool
 	}
 	tests := []struct {
 		name    string
+		field   field
 		args    args
 		want    []string
 		wantErr bool
 	}{
 		{
 			name: "simple test",
-			args: args{
+			field: field{
-				aclPolicy: ACLPolicy{
+				pol: ACLPolicy{
 					Groups: Groups{
 						"group:test": []string{"user1", "user2", "user3"},
 						"group:foo":  []string{"user2", "user3"},
 					},
 				},
+			},
+			args: args{
 				group:            "group:test",
 				stripEmailDomain: true,
 			},
@@ -584,13 +589,15 @@ func Test_expandGroup(t *testing.T) {
 		},
 		{
 			name: "InexistantGroup",
-			args: args{
+			field: field{
-				aclPolicy: ACLPolicy{
+				pol: ACLPolicy{
 					Groups: Groups{
 						"group:test": []string{"user1", "user2", "user3"},
 						"group:foo":  []string{"user2", "user3"},
 					},
 				},
+			},
+			args: args{
 				group:            "group:undefined",
 				stripEmailDomain: true,
 			},
@@ -599,8 +606,8 @@ func Test_expandGroup(t *testing.T) {
 		},
 		{
 			name: "Expand emails in group",
-			args: args{
+			field: field{
-				aclPolicy: ACLPolicy{
+				pol: ACLPolicy{
 					Groups: Groups{
 						"group:admin": []string{
 							"joe.bar@gmail.com",
@@ -608,6 +615,8 @@ func Test_expandGroup(t *testing.T) {
 						},
 					},
 				},
+			},
+			args: args{
 				group:            "group:admin",
 				stripEmailDomain: true,
 			},
@@ -616,8 +625,8 @@ func Test_expandGroup(t *testing.T) {
 		},
 		{
 			name: "Expand emails in group",
-			args: args{
+			field: field{
-				aclPolicy: ACLPolicy{
+				pol: ACLPolicy{
 					Groups: Groups{
 						"group:admin": []string{
 							"joe.bar@gmail.com",
@@ -625,6 +634,8 @@ func Test_expandGroup(t *testing.T) {
 						},
 					},
 				},
+			},
+			args: args{
 				group:            "group:admin",
 				stripEmailDomain: false,
 			},
@@ -634,8 +645,7 @@ func Test_expandGroup(t *testing.T) {
 	}
 	for _, test := range tests {
 		t.Run(test.name, func(t *testing.T) {
-			got, err := expandGroup(
+			got, err := test.field.pol.getUsersInGroup(
-				test.args.aclPolicy,
 				test.args.group,
 				test.args.stripEmailDomain,
 			)
@@ -653,7 +663,7 @@ func Test_expandGroup(t *testing.T) {
 
 func Test_expandTagOwners(t *testing.T) {
 	type args struct {
-		aclPolicy        ACLPolicy
+		aclPolicy        *ACLPolicy
 		tag              string
 		stripEmailDomain bool
 	}
@@ -666,7 +676,7 @@ func Test_expandTagOwners(t *testing.T) {
 		{
 			name: "simple tag expansion",
 			args: args{
-				aclPolicy: ACLPolicy{
+				aclPolicy: &ACLPolicy{
 					TagOwners: TagOwners{"tag:test": []string{"user1"}},
 				},
 				tag:              "tag:test",
@@ -678,7 +688,7 @@ func Test_expandTagOwners(t *testing.T) {
 		{
 			name: "expand with tag and group",
 			args: args{
-				aclPolicy: ACLPolicy{
+				aclPolicy: &ACLPolicy{
 					Groups:    Groups{"group:foo": []string{"user1", "user2"}},
 					TagOwners: TagOwners{"tag:test": []string{"group:foo"}},
 				},
@@ -691,7 +701,7 @@ func Test_expandTagOwners(t *testing.T) {
 		{
 			name: "expand with user and group",
 			args: args{
-				aclPolicy: ACLPolicy{
+				aclPolicy: &ACLPolicy{
 					Groups:    Groups{"group:foo": []string{"user1", "user2"}},
 					TagOwners: TagOwners{"tag:test": []string{"group:foo", "user3"}},
 				},
@@ -704,7 +714,7 @@ func Test_expandTagOwners(t *testing.T) {
 		{
 			name: "invalid tag",
 			args: args{
-				aclPolicy: ACLPolicy{
+				aclPolicy: &ACLPolicy{
 					TagOwners: TagOwners{"tag:foo": []string{"group:foo", "user1"}},
 				},
 				tag:              "tag:test",
@@ -716,7 +726,7 @@ func Test_expandTagOwners(t *testing.T) {
 		{
 			name: "invalid group",
 			args: args{
-				aclPolicy: ACLPolicy{
+				aclPolicy: &ACLPolicy{
 					Groups:    Groups{"group:bar": []string{"user1", "user2"}},
 					TagOwners: TagOwners{"tag:test": []string{"group:foo", "user2"}},
 				},
@@ -729,7 +739,7 @@ func Test_expandTagOwners(t *testing.T) {
 	}
 	for _, test := range tests {
 		t.Run(test.name, func(t *testing.T) {
-			got, err := expandTagOwners(
+			got, err := getTagOwners(
 				test.args.aclPolicy,
 				test.args.tag,
 				test.args.stripEmailDomain,
@@ -908,6 +918,9 @@ func Test_listMachinesInUser(t *testing.T) {
 }
 
 func Test_expandAlias(t *testing.T) {
+	type field struct {
+		pol ACLPolicy
+	}
 	type args struct {
 		machines         []Machine
 		aclPolicy        ACLPolicy
@@ -916,12 +929,16 @@ func Test_expandAlias(t *testing.T) {
 	}
 	tests := []struct {
 		name    string
+		field   field
 		args    args
 		want    []string
 		wantErr bool
 	}{
 		{
 			name: "wildcard",
+			field: field{
+				pol: ACLPolicy{},
+			},
 			args: args{
 				alias: "*",
 				machines: []Machine{
@@ -932,7 +949,6 @@ func Test_expandAlias(t *testing.T) {
 						},
 					},
 				},
-				aclPolicy:        ACLPolicy{},
 				stripEmailDomain: true,
 			},
 			want:    []string{"*"},
@@ -940,6 +956,11 @@ func Test_expandAlias(t *testing.T) {
 		},
 		{
 			name: "simple group",
+			field: field{
+				pol: ACLPolicy{
+					Groups: Groups{"group:accountant": []string{"joe", "marc"}},
+				},
+			},
 			args: args{
 				alias: "group:accountant",
 				machines: []Machine{
@@ -968,9 +989,6 @@ func Test_expandAlias(t *testing.T) {
 						User: User{Name: "mickael"},
 					},
 				},
-				aclPolicy: ACLPolicy{
-					Groups: Groups{"group:accountant": []string{"joe", "marc"}},
-				},
 				stripEmailDomain: true,
 			},
 			want:    []string{"100.64.0.1", "100.64.0.2", "100.64.0.3"},
@@ -978,6 +996,11 @@ func Test_expandAlias(t *testing.T) {
 		},
 		{
 			name: "wrong group",
+			field: field{
+				pol: ACLPolicy{
+					Groups: Groups{"group:accountant": []string{"joe", "marc"}},
+				},
+			},
 			args: args{
 				alias: "group:hr",
 				machines: []Machine{
@@ -1006,9 +1029,6 @@ func Test_expandAlias(t *testing.T) {
 						User: User{Name: "mickael"},
 					},
 				},
-				aclPolicy: ACLPolicy{
-					Groups: Groups{"group:accountant": []string{"joe", "marc"}},
-				},
 				stripEmailDomain: true,
 			},
 			want:    []string{},
@@ -1016,10 +1036,12 @@ func Test_expandAlias(t *testing.T) {
 		},
 		{
 			name: "simple ipaddress",
+			field: field{
+				pol: ACLPolicy{},
+			},
 			args: args{
 				alias:            "10.0.0.3",
 				machines:         []Machine{},
-				aclPolicy:        ACLPolicy{},
 				stripEmailDomain: true,
 			},
 			want:    []string{"10.0.0.3"},
@@ -1027,10 +1049,12 @@ func Test_expandAlias(t *testing.T) {
 		},
 		{
 			name: "simple host by ip passed through",
+			field: field{
+				pol: ACLPolicy{},
+			},
 			args: args{
 				alias:            "10.0.0.1",
 				machines:         []Machine{},
-				aclPolicy:        ACLPolicy{},
 				stripEmailDomain: true,
 			},
 			want:    []string{"10.0.0.1"},
@@ -1038,6 +1062,9 @@ func Test_expandAlias(t *testing.T) {
 		},
 		{
 			name: "simple host by ipv4 single ipv4",
+			field: field{
+				pol: ACLPolicy{},
+			},
 			args: args{
 				alias: "10.0.0.1",
 				machines: []Machine{
@@ -1048,7 +1075,6 @@ func Test_expandAlias(t *testing.T) {
 						User: User{Name: "mickael"},
 					},
 				},
-				aclPolicy:        ACLPolicy{},
 				stripEmailDomain: true,
 			},
 			want:    []string{"10.0.0.1"},
@@ -1056,6 +1082,9 @@ func Test_expandAlias(t *testing.T) {
 		},
 		{
 			name: "simple host by ipv4 single dual stack",
+			field: field{
+				pol: ACLPolicy{},
+			},
 			args: args{
 				alias: "10.0.0.1",
 				machines: []Machine{
@@ -1067,7 +1096,6 @@ func Test_expandAlias(t *testing.T) {
 						User: User{Name: "mickael"},
 					},
 				},
-				aclPolicy:        ACLPolicy{},
 				stripEmailDomain: true,
 			},
 			want:    []string{"10.0.0.1", "fd7a:115c:a1e0:ab12:4843:2222:6273:2222"},
@@ -1075,6 +1103,9 @@ func Test_expandAlias(t *testing.T) {
 		},
 		{
 			name: "simple host by ipv6 single dual stack",
+			field: field{
+				pol: ACLPolicy{},
+			},
 			args: args{
 				alias: "fd7a:115c:a1e0:ab12:4843:2222:6273:2222",
 				machines: []Machine{
@@ -1086,7 +1117,6 @@ func Test_expandAlias(t *testing.T) {
 						User: User{Name: "mickael"},
 					},
 				},
-				aclPolicy:        ACLPolicy{},
 				stripEmailDomain: true,
 			},
 			want:    []string{"fd7a:115c:a1e0:ab12:4843:2222:6273:2222", "10.0.0.1"},
@@ -1094,14 +1124,16 @@ func Test_expandAlias(t *testing.T) {
 		},
 		{
 			name: "simple host by hostname alias",
-			args: args{
+			field: field{
-				alias:    "testy",
+				pol: ACLPolicy{
-				machines: []Machine{},
-				aclPolicy: ACLPolicy{
 					Hosts: Hosts{
 						"testy": netip.MustParsePrefix("10.0.0.132/32"),
 					},
 				},
+			},
+			args: args{
+				alias:            "testy",
+				machines:         []Machine{},
 				stripEmailDomain: true,
 			},
 			want:    []string{"10.0.0.132/32"},
@@ -1109,14 +1141,16 @@ func Test_expandAlias(t *testing.T) {
 		},
 		{
 			name: "private network",
-			args: args{
+			field: field{
-				alias:    "homeNetwork",
+				pol: ACLPolicy{
-				machines: []Machine{},
-				aclPolicy: ACLPolicy{
 					Hosts: Hosts{
 						"homeNetwork": netip.MustParsePrefix("192.168.1.0/24"),
 					},
 				},
+			},
+			args: args{
+				alias:            "homeNetwork",
+				machines:         []Machine{},
 				stripEmailDomain: true,
 			},
 			want:    []string{"192.168.1.0/24"},
@@ -1124,6 +1158,9 @@ func Test_expandAlias(t *testing.T) {
 		},
 		{
 			name: "simple CIDR",
+			field: field{
+				pol: ACLPolicy{},
+			},
 			args: args{
 				alias:            "10.0.0.0/16",
 				machines:         []Machine{},
@@ -1135,6 +1172,11 @@ func Test_expandAlias(t *testing.T) {
 		},
 		{
 			name: "simple tag",
+			field: field{
+				pol: ACLPolicy{
+					TagOwners: TagOwners{"tag:hr-webserver": []string{"joe"}},
+				},
+			},
 			args: args{
 				alias: "tag:hr-webserver",
 				machines: []Machine{
@@ -1173,9 +1215,6 @@ func Test_expandAlias(t *testing.T) {
 						User: User{Name: "joe"},
 					},
 				},
-				aclPolicy: ACLPolicy{
-					TagOwners: TagOwners{"tag:hr-webserver": []string{"joe"}},
-				},
 				stripEmailDomain: true,
 			},
 			want:    []string{"100.64.0.1", "100.64.0.2"},
@@ -1183,6 +1222,14 @@ func Test_expandAlias(t *testing.T) {
 		},
 		{
 			name: "No tag defined",
+			field: field{
+				pol: ACLPolicy{
+					Groups: Groups{"group:accountant": []string{"joe", "marc"}},
+					TagOwners: TagOwners{
+						"tag:accountant-webserver": []string{"group:accountant"},
+					},
+				},
+			},
 			args: args{
 				alias: "tag:hr-webserver",
 				machines: []Machine{
@@ -1211,12 +1258,6 @@ func Test_expandAlias(t *testing.T) {
 						User: User{Name: "mickael"},
 					},
 				},
-				aclPolicy: ACLPolicy{
-					Groups: Groups{"group:accountant": []string{"joe", "marc"}},
-					TagOwners: TagOwners{
-						"tag:accountant-webserver": []string{"group:accountant"},
-					},
-				},
 				stripEmailDomain: true,
 			},
 			want:    []string{},
@@ -1224,6 +1265,9 @@ func Test_expandAlias(t *testing.T) {
 		},
 		{
 			name: "Forced tag defined",
+			field: field{
+				pol: ACLPolicy{},
+			},
 			args: args{
 				alias: "tag:hr-webserver",
 				machines: []Machine{
@@ -1254,7 +1298,6 @@ func Test_expandAlias(t *testing.T) {
 						User: User{Name: "mickael"},
 					},
 				},
-				aclPolicy:        ACLPolicy{},
 				stripEmailDomain: true,
 			},
 			want:    []string{"100.64.0.1", "100.64.0.2"},
@@ -1262,6 +1305,13 @@ func Test_expandAlias(t *testing.T) {
 		},
 		{
 			name: "Forced tag with legitimate tagOwner",
+			field: field{
+				pol: ACLPolicy{
+					TagOwners: TagOwners{
+						"tag:hr-webserver": []string{"joe"},
+					},
+				},
+			},
 			args: args{
 				alias: "tag:hr-webserver",
 				machines: []Machine{
@@ -1296,11 +1346,6 @@ func Test_expandAlias(t *testing.T) {
 						User: User{Name: "mickael"},
 					},
 				},
-				aclPolicy: ACLPolicy{
-					TagOwners: TagOwners{
-						"tag:hr-webserver": []string{"joe"},
-					},
-				},
 				stripEmailDomain: true,
 			},
 			want:    []string{"100.64.0.1", "100.64.0.2"},
@@ -1308,6 +1353,11 @@ func Test_expandAlias(t *testing.T) {
 		},
 		{
 			name: "list host in user without correctly tagged servers",
+			field: field{
+				pol: ACLPolicy{
+					TagOwners: TagOwners{"tag:accountant-webserver": []string{"joe"}},
+				},
+			},
 			args: args{
 				alias: "joe",
 				machines: []Machine{
@@ -1346,9 +1396,6 @@ func Test_expandAlias(t *testing.T) {
 						User: User{Name: "joe"},
 					},
 				},
-				aclPolicy: ACLPolicy{
-					TagOwners: TagOwners{"tag:accountant-webserver": []string{"joe"}},
-				},
 				stripEmailDomain: true,
 			},
 			want:    []string{"100.64.0.4"},
@@ -1357,9 +1404,8 @@ func Test_expandAlias(t *testing.T) {
 	}
 	for _, test := range tests {
 		t.Run(test.name, func(t *testing.T) {
-			got, err := expandAlias(
+			got, err := test.field.pol.expandAlias(
 				test.args.machines,
-				test.args.aclPolicy,
 				test.args.alias,
 				test.args.stripEmailDomain,
 			)
@@ -1377,7 +1423,7 @@ func Test_expandAlias(t *testing.T) {
 
 func Test_excludeCorrectlyTaggedNodes(t *testing.T) {
 	type args struct {
-		aclPolicy        ACLPolicy
+		aclPolicy        *ACLPolicy
 		nodes            []Machine
 		user             string
 		stripEmailDomain bool
@@ -1391,7 +1437,7 @@ func Test_excludeCorrectlyTaggedNodes(t *testing.T) {
 		{
 			name: "exclude nodes with valid tags",
 			args: args{
-				aclPolicy: ACLPolicy{
+				aclPolicy: &ACLPolicy{
 					TagOwners: TagOwners{"tag:accountant-webserver": []string{"joe"}},
 				},
 				nodes: []Machine{
@@ -1437,7 +1483,7 @@ func Test_excludeCorrectlyTaggedNodes(t *testing.T) {
 		{
 			name: "exclude nodes with valid tags, and owner is in a group",
 			args: args{
-				aclPolicy: ACLPolicy{
+				aclPolicy: &ACLPolicy{
 					Groups: Groups{
 						"group:accountant": []string{"joe", "bar"},
 					},
@@ -1488,7 +1534,7 @@ func Test_excludeCorrectlyTaggedNodes(t *testing.T) {
 		{
 			name: "exclude nodes with valid tags and with forced tags",
 			args: args{
-				aclPolicy: ACLPolicy{
+				aclPolicy: &ACLPolicy{
 					TagOwners: TagOwners{"tag:accountant-webserver": []string{"joe"}},
 				},
 				nodes: []Machine{
@@ -1530,7 +1576,7 @@ func Test_excludeCorrectlyTaggedNodes(t *testing.T) {
 		{
 			name: "all nodes have invalid tags, don't exclude them",
 			args: args{
-				aclPolicy: ACLPolicy{
+				aclPolicy: &ACLPolicy{
 					TagOwners: TagOwners{"tag:accountant-webserver": []string{"joe"}},
 				},
 				nodes: []Machine{

acls_types.go

@@ -111,8 +111,8 @@ func (hosts *Hosts) UnmarshalYAML(data []byte) error {
 }
 
 // IsZero is perhaps a bit naive here.
-func (policy ACLPolicy) IsZero() bool {
+func (pol ACLPolicy) IsZero() bool {
-	if len(policy.Groups) == 0 && len(policy.Hosts) == 0 && len(policy.ACLs) == 0 {
+	if len(pol.Groups) == 0 && len(pol.Hosts) == 0 && len(pol.ACLs) == 0 {
 		return true
 	}
 

machine.go

@@ -893,7 +893,7 @@ func getTags(
 	validTagMap := make(map[string]bool)
 	invalidTagMap := make(map[string]bool)
 	for _, tag := range machine.HostInfo.RequestTags {
-		owners, err := expandTagOwners(*aclPolicy, tag, stripEmailDomain)
+		owners, err := getTagOwners(aclPolicy, tag, stripEmailDomain)
 		if errors.Is(err, errInvalidTag) {
 			invalidTagMap[tag] = true
 
@@ -1207,7 +1207,7 @@ func (h *Headscale) EnableAutoApprovedRoutes(machine *Machine) error {
 			if approvedAlias == machine.User.Name {
 				approvedRoutes = append(approvedRoutes, advertisedRoute)
 			} else {
-				approvedIps, err := expandAlias([]Machine{*machine}, *h.aclPolicy, approvedAlias, h.cfg.OIDC.StripEmaildomain)
+				approvedIps, err := h.aclPolicy.expandAlias([]Machine{*machine}, approvedAlias, h.cfg.OIDC.StripEmaildomain)
 				if err != nil {
 					log.Err(err).
 						Str("alias", approvedAlias).