net/{interfaces,netcheck}: rename some fields, funcs

Split out of Denton's #2164, to make that diff smaller to review.

This change has no behavior changes.

Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>

net/interfaces/interfaces.go

@@ -213,9 +213,9 @@ type State struct {
 	InterfaceIPs map[string][]netaddr.IPPrefix
 	Interface    map[string]Interface
 
-	// HaveV6Global is whether this machine has an IPv6 global address
-	// on some non-Tailscale interface that's up.
-	HaveV6Global bool
+	// HaveV6 is whether this machine has an IPv6 Global or Unique Local Address
+	// which might provide connectivity on a non-Tailscale interface that's up.
+	HaveV6 bool
 
 	// HaveV4 is whether the machine has some non-localhost,
 	// non-link-local IPv4 address on a non-Tailscale interface that's up.
@@ -289,7 +289,7 @@ func (s *State) String() string {
 	if s.PAC != "" {
 		fmt.Fprintf(&sb, " pac=%s", s.PAC)
 	}
-	fmt.Fprintf(&sb, " v4=%v v6global=%v}", s.HaveV4, s.HaveV6Global)
+	fmt.Fprintf(&sb, " v4=%v v6=%v}", s.HaveV4, s.HaveV6)
 	return sb.String()
 }
 
@@ -302,7 +302,7 @@ func (s *State) EqualFiltered(s2 *State, filter func(i Interface, ips []netaddr.
 	if s == nil || s2 == nil {
 		return false
 	}
-	if s.HaveV6Global != s2.HaveV6Global ||
+	if s.HaveV6 != s2.HaveV6 ||
 		s.HaveV4 != s2.HaveV4 ||
 		s.IsExpensive != s2.IsExpensive ||
 		s.DefaultRouteInterface != s2.DefaultRouteInterface ||
@@ -362,7 +362,7 @@ 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)
+	return s != nil && (s.HaveV4 || s.HaveV6)
 }
 
 func hasTailscaleIP(pfxs []netaddr.IPPrefix) bool {
@@ -410,7 +410,7 @@ func GetState() (*State, error) {
 			if pfx.IP().IsLoopback() || pfx.IP().IsLinkLocalUnicast() {
 				continue
 			}
-			s.HaveV6Global = s.HaveV6Global || isGlobalV6(pfx.IP())
+			s.HaveV6 = s.HaveV6 || isUsableV6(pfx.IP())
 			s.HaveV4 = s.HaveV4 || pfx.IP().Is4()
 		}
 	}); err != nil {
@@ -503,7 +503,7 @@ func isPrivateIP(ip netaddr.IP) bool {
 	return private1.Contains(ip) || private2.Contains(ip) || private3.Contains(ip)
 }
 
-func isGlobalV6(ip netaddr.IP) bool {
+func isUsableV6(ip netaddr.IP) bool {
 	return v6Global1.Contains(ip) ||
 		(tsaddr.IsULA(ip) && !tsaddr.TailscaleULARange().Contains(ip))
 }

net/interfaces/interfaces_test.go

@@ -46,7 +46,7 @@ func TestLikelyHomeRouterIP(t *testing.T) {
 	t.Logf("myIP = %v; gw = %v", my, gw)
 }
 
-func TestIsGlobalV6(t *testing.T) {
+func TestIsUsableV6(t *testing.T) {
 	tests := []struct {
 		name string
 		ip   string
@@ -61,8 +61,8 @@ func TestIsGlobalV6(t *testing.T) {
 	}
 
 	for _, test := range tests {
-		if got := isGlobalV6(netaddr.MustParseIP(test.ip)); got != test.want {
-			t.Errorf("isGlobalV6(%s) = %v, want %v", test.name, got, test.want)
+		if got := isUsableV6(netaddr.MustParseIP(test.ip)); got != test.want {
+			t.Errorf("isUsableV6(%s) = %v, want %v", test.name, got, test.want)
 		}
 	}
 }

net/netcheck/netcheck.go

@@ -336,7 +336,7 @@ func makeProbePlan(dm *tailcfg.DERPMap, ifState *interfaces.State, last *Report)
 	if last == nil || len(last.RegionLatency) == 0 {
 		return makeProbePlanInitial(dm, ifState)
 	}
-	have6if := ifState.HaveV6Global
+	have6if := ifState.HaveV6
 	have4if := ifState.HaveV4
 	plan = make(probePlan)
 	if !have4if && !have6if {
@@ -425,7 +425,7 @@ func makeProbePlanInitial(dm *tailcfg.DERPMap, ifState *interfaces.State) (plan
 			if ifState.HaveV4 && nodeMight4(n) {
 				p4 = append(p4, probe{delay: delay, node: n.Name, proto: probeIPv4})
 			}
-			if ifState.HaveV6Global && nodeMight6(n) {
+			if ifState.HaveV6 && nodeMight6(n) {
 				p6 = append(p6, probe{delay: delay, node: n.Name, proto: probeIPv6})
 			}
 		}
@@ -808,7 +808,7 @@ func (c *Client) GetReport(ctx context.Context, dm *tailcfg.DERPMap) (*Report, e
 		go c.readPackets(ctx, u4)
 	}
 
-	if ifState.HaveV6Global {
+	if ifState.HaveV6 {
 		if f := c.GetSTUNConn6; f != nil {
 			rs.pc6 = f()
 		} else {

net/netcheck/netcheck_test.go

@@ -443,8 +443,8 @@ func TestMakeProbePlan(t *testing.T) {
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			ifState := &interfaces.State{
-				HaveV6Global: tt.have6if,
-				HaveV4:       !tt.no4,
+				HaveV6: tt.have6if,
+				HaveV4: !tt.no4,
 			}
 			got := makeProbePlan(tt.dm, ifState, tt.last)
 			if !reflect.DeepEqual(got, tt.want) {