1 files changed, 73 insertions, 44 deletions

diff --git a/net/interfaces/interfaces.go b/net/interfaces/interfaces.go
index 3a0ffeb0b..f2988af34 100644
--- a/net/interfaces/interfaces.go
+++ b/net/interfaces/interfaces.go
@@ -6,10 +6,10 @@
 package interfaces
 
 import (
+	"bytes"
 	"fmt"
 	"net"
 	"net/http"
-	"reflect"
 	"runtime"
 	"sort"
 	"strings"
@@ -190,6 +190,9 @@ func ForeachInterface(fn func(Interface, []netaddr.IPPrefix)) error {
 				}
 			}
 		}
+		sort.Slice(pfxs, func(i, j int) bool {
+			return pfxs[i].IP.Less(pfxs[j].IP)
+		})
 		fn(Interface{iface}, pfxs)
 	}
 	return nil
@@ -204,7 +207,7 @@ type State struct {
 	// IPPrefix, where the IP is the interface IP address and Bits is
 	// the subnet mask.
 	InterfaceIPs map[string][]netaddr.IPPrefix
-	InterfaceUp  map[string]bool
+	Interface    map[string]Interface
 
 	// HaveV6Global is whether this machine has an IPv6 global address
 	// on some non-Tailscale interface that's up.
@@ -235,14 +238,14 @@ type State struct {
 func (s *State) String() string {
 	var sb strings.Builder
 	fmt.Fprintf(&sb, "interfaces.State{defaultRoute=%v ifs={", s.DefaultRouteInterface)
-	ifs := make([]string, 0, len(s.InterfaceUp))
-	for k := range s.InterfaceUp {
+	ifs := make([]string, 0, len(s.Interface))
+	for k := range s.Interface {
 		if anyInterestingIP(s.InterfaceIPs[k]) {
 			ifs = append(ifs, k)
 		}
 	}
 	sort.Slice(ifs, func(i, j int) bool {
-		upi, upj := s.InterfaceUp[ifs[i]], s.InterfaceUp[ifs[j]]
+		upi, upj := s.Interface[ifs[i]].IsUp(), s.Interface[ifs[j]].IsUp()
 		if upi != upj {
 			// Up sorts before down.
 			return upi
@@ -253,7 +256,7 @@ func (s *State) String() string {
 		if i > 0 {
 			sb.WriteString(" ")
 		}
-		if s.InterfaceUp[ifName] {
+		if s.Interface[ifName].IsUp() {
 			fmt.Fprintf(&sb, "%s:[", ifName)
 			needSpace := false
 			for _, pfx := range s.InterfaceIPs[ifName] {
@@ -286,50 +289,76 @@ func (s *State) String() string {
 	return sb.String()
 }
 
-func (s *State) Equal(s2 *State) bool {
-	return reflect.DeepEqual(s, s2)
-}
-
-func (s *State) HasPAC() bool { return s != nil && s.PAC != "" }
-
-// AnyInterfaceUp reports whether any interface seems like it has Internet access.
-func (s *State) AnyInterfaceUp() bool {
-	return s != nil && (s.HaveV4 || s.HaveV6Global)
-}
-
-// RemoveUninterestingInterfacesAndAddresses removes uninteresting IPs
-// from InterfaceIPs, also removing from both the InterfaceIPs and
-// InterfaceUp map any interfaces that don't have any interesting IPs.
-func (s *State) RemoveUninterestingInterfacesAndAddresses() {
-	for ifName := range s.InterfaceUp {
-		ips := s.InterfaceIPs[ifName]
-		keep := ips[:0]
-		for _, pfx := range ips {
-			if isInterestingIP(pfx.IP) {
-				keep = append(keep, pfx)
-			}
-		}
-		if len(keep) == 0 {
-			delete(s.InterfaceUp, ifName)
-			delete(s.InterfaceIPs, ifName)
+// EqualFiltered reports whether s and s2 are equal,
+// considering only interfaces in s for which filter returns true.
+func (s *State) EqualFiltered(s2 *State, filter func(i Interface, ips []netaddr.IPPrefix) bool) bool {
+	if s == nil && s2 == nil {
+		return true
+	}
+	if s == nil || s2 == nil {
+		return false
+	}
+	if s.HaveV6Global != s2.HaveV6Global ||
+		s.HaveV4 != s2.HaveV4 ||
+		s.IsExpensive != s2.IsExpensive ||
+		s.DefaultRouteInterface != s2.DefaultRouteInterface ||
+		s.HTTPProxy != s2.HTTPProxy ||
+		s.PAC != s2.PAC {
+		return false
+	}
+	for iname, i := range s.Interface {
+		ips := s.InterfaceIPs[iname]
+		if !filter(i, ips) {
 			continue
 		}
-		if len(keep) < len(ips) {
-			s.InterfaceIPs[ifName] = keep
+		i2, ok := s2.Interface[iname]
+		if !ok {
+			return false
+		}
+		ips2, ok := s2.InterfaceIPs[iname]
+		if !ok {
+			return false
+		}
+		if !interfacesEqual(i, i2) || !prefixesEqual(ips, ips2) {
+			return false
 		}
 	}
+	return true
+}
+
+func interfacesEqual(a, b Interface) bool {
+	return a.Index == b.Index &&
+		a.MTU == b.MTU &&
+		a.Name == b.Name &&
+		a.Flags == b.Flags &&
+		bytes.Equal([]byte(a.HardwareAddr), []byte(b.HardwareAddr))
 }
 
-// RemoveTailscaleInterfaces modifes s to remove any interfaces that
-// are owned by this process. (TODO: make this true; currently it
-// uses some heuristics)
-func (s *State) RemoveTailscaleInterfaces() {
-	for name, pfxs := range s.InterfaceIPs {
-		if isTailscaleInterface(name, pfxs) {
-			delete(s.InterfaceIPs, name)
-			delete(s.InterfaceUp, name)
+func prefixesEqual(a, b []netaddr.IPPrefix) bool {
+	if len(a) != len(b) {
+		return false
+	}
+	for i, v := range a {
+		if b[i] != v {
+			return false
 		}
 	}
+	return true
+}
+
+// FilterInteresting reports whether i is an interesting non-Tailscale interface.
+func FilterInteresting(i Interface, ips []netaddr.IPPrefix) bool {
+	return !isTailscaleInterface(i.Name, ips) && anyInterestingIP(ips)
+}
+
+// FilterAll always returns true, to use EqualFiltered against all interfaces.
+func FilterAll(i Interface, ips []netaddr.IPPrefix) bool { return true }
+
+func (s *State) HasPAC() bool { return s != nil && s.PAC != "" }
+
+// AnyInterfaceUp reports whether any interface seems like it has Internet access.
+func (s *State) AnyInterfaceUp() bool {
+	return s != nil && (s.HaveV4 || s.HaveV6Global)
 }
 
 func hasTailscaleIP(pfxs []netaddr.IPPrefix) bool {
@@ -364,11 +393,11 @@ var getPAC func() string
 func GetState() (*State, error) {
 	s := &State{
 		InterfaceIPs: make(map[string][]netaddr.IPPrefix),
-		InterfaceUp:  make(map[string]bool),
+		Interface:    make(map[string]Interface),
 	}
 	if err := ForeachInterface(func(ni Interface, pfxs []netaddr.IPPrefix) {
 		ifUp := ni.IsUp()
-		s.InterfaceUp[ni.Name] = ifUp
+		s.Interface[ni.Name] = ni
 		s.InterfaceIPs[ni.Name] = append(s.InterfaceIPs[ni.Name], pfxs...)
 		if !ifUp || isTailscaleInterface(ni.Name, pfxs) {
 			return