wgengine/filter: remove the Matches type.

It only served to obscure the underlying slice type without
adding much value.

Signed-off-by: David Anderson <danderson@tailscale.com>

control/controlclient/filter.go

@@ -9,9 +9,9 @@ import (
 	"tailscale.com/wgengine/filter"
 )
 
-// Parse a backward-compatible FilterRule used by control's wire format,
+// Parse a backward-compatible FilterRule used by control's wire
-// producing the most current filter.Matches format.
+// format, producing the most current filter format.
-func (c *Direct) parsePacketFilter(pf []tailcfg.FilterRule) filter.Matches {
+func (c *Direct) parsePacketFilter(pf []tailcfg.FilterRule) []filter.Match {
 	mm, err := filter.MatchesFromFilterRules(pf)
 	if err != nil {
 		c.logf("parsePacketFilter: %s\n", err)

control/controlclient/netmap.go

@@ -34,7 +34,7 @@ type NetworkMap struct {
 	Peers         []*tailcfg.Node // sorted by Node.ID
 	DNS           tailcfg.DNSConfig
 	Hostinfo      tailcfg.Hostinfo
-	PacketFilter  filter.Matches
+	PacketFilter  []filter.Match
 
 	// DERPMap is the last DERP server map received. It's reused
 	// between updates and should not be modified.

ipn/local.go

@@ -523,7 +523,7 @@ func (b *LocalBackend) updateFilter(netMap *controlclient.NetworkMap, prefs *Pre
 	var (
 		haveNetmap   = netMap != nil
 		addrs        []wgcfg.CIDR
-		packetFilter filter.Matches
+		packetFilter []filter.Match
 		advRoutes    []wgcfg.CIDR
 		shieldsUp    = prefs == nil || prefs.ShieldsUp // Be conservative when not ready
 	)
@@ -551,7 +551,7 @@ func (b *LocalBackend) updateFilter(netMap *controlclient.NetworkMap, prefs *Pre
 	if shieldsUp {
 		b.logf("netmap packet filter: (shields up)")
 		var prevFilter *filter.Filter // don't reuse old filter state
-		b.e.SetFilter(filter.New(filter.Matches{}, localNets, prevFilter, b.logf))
+		b.e.SetFilter(filter.New(nil, localNets, prevFilter, b.logf))
 	} else {
 		b.logf("netmap packet filter: %v", packetFilter)
 		b.e.SetFilter(filter.New(packetFilter, localNets, b.e.GetFilter(), b.logf))

wgengine/filter/filter.go

@@ -92,7 +92,7 @@ const (
 // NewAllowAll returns a packet filter that accepts everything to and
 // from localNets.
 func NewAllowAll(localNets []netaddr.IPPrefix, logf logger.Logf) *Filter {
-	return New(Matches{Match{NetPortRangeAny, NetAny}}, localNets, nil, logf)
+	return New([]Match{Match{NetPortRangeAny, NetAny}}, localNets, nil, logf)
 }
 
 // NewAllowNone returns a packet filter that rejects everything.
@@ -105,7 +105,7 @@ func NewAllowNone(logf logger.Logf) *Filter {
 // by matches. If shareStateWith is non-nil, the returned filter
 // shares state with the previous one, to enable changing rules at
 // runtime without breaking existing stateful flows.
-func New(matches Matches, localNets []netaddr.IPPrefix, shareStateWith *Filter, logf logger.Logf) *Filter {
+func New(matches []Match, localNets []netaddr.IPPrefix, shareStateWith *Filter, logf logger.Logf) *Filter {
 	var state *filterState
 	if shareStateWith != nil {
 		state = shareStateWith.state

wgengine/filter/filter_test.go

@@ -97,7 +97,7 @@ func netports(netPorts ...string) (ret []NetPortRange) {
 	return ret
 }
 
-var matches = Matches{
+var matches = []Match{
 	{Srcs: nets("8.1.1.1", "8.2.2.2"), Dsts: netports("1.2.3.4:22", "5.6.7.8:23-24")},
 	{Srcs: nets("8.1.1.1", "8.2.2.2"), Dsts: netports("5.6.7.8:27-28")},
 	{Srcs: nets("2.2.2.2"), Dsts: netports("8.1.1.1:22")},
@@ -115,13 +115,13 @@ func newFilter(logf logger.Logf) *Filter {
 }
 
 func TestMarshal(t *testing.T) {
-	for _, ent := range []Matches{Matches{matches[0]}, matches} {
+	for _, ent := range [][]Match{[]Match{matches[0]}, matches} {
 		b, err := json.Marshal(ent)
 		if err != nil {
 			t.Fatalf("marshal: %v", err)
 		}
 
-		mm2 := Matches{}
+		mm2 := []Match{}
 		if err := json.Unmarshal(b, &mm2); err != nil {
 			t.Fatalf("unmarshal: %v (%v)", err, string(b))
 		}

wgengine/filter/match.go

@@ -81,6 +81,3 @@ func (m Match) String() string {
 	}
 	return fmt.Sprintf("%v=>%v", ss, ds)
 }
-
-// Matches is a list of packet matchers.
-type Matches []Match

wgengine/filter/match4.go

@@ -80,7 +80,7 @@ func (ms matches4) String() string {
 	return b.String()
 }
 
-func newMatches4(ms Matches) (ret matches4) {
+func newMatches4(ms []Match) (ret matches4) {
 	for _, m := range ms {
 		var m4 match4
 		for _, src := range m.Srcs {

wgengine/filter/tailcfg.go

@@ -14,7 +14,7 @@ import (
 // MatchesFromFilterRules converts tailcfg FilterRules into Matches.
 // If an error is returned, the Matches result is still valid,
 // containing the rules that were successfully converted.
-func MatchesFromFilterRules(pf []tailcfg.FilterRule) (Matches, error) {
+func MatchesFromFilterRules(pf []tailcfg.FilterRule) ([]Match, error) {
 	mm := make([]Match, 0, len(pf))
 	var erracc error
 

wgengine/tstun/tun_test.go

@@ -98,7 +98,7 @@ func netports(netPorts ...string) (ret []filter.NetPortRange) {
 }
 
 func setfilter(logf logger.Logf, tun *TUN) {
-	matches := filter.Matches{
+	matches := []filter.Match{
 		{Srcs: nets("5.6.7.8"), Dsts: netports("1.2.3.4:89-90")},
 		{Srcs: nets("1.2.3.4"), Dsts: netports("5.6.7.8:98")},
 	}