Stop using DHCP on iOS and tvOS

We do not have the `com.apple.developer.networking.multicast` entitlement and are unable to obtain it for non-technical reasons.

cmd/internal/build_libbox/main.go

@@ -46,7 +46,7 @@ var (
 	sharedFlags []string
 	debugFlags  []string
 	sharedTags  []string
-	darwinTags  []string
+	macOSTags   []string
 	memcTags    []string
 	notMemcTags []string
 	debugTags   []string
@@ -63,7 +63,7 @@ func init() {
 	debugFlags = append(debugFlags, "-ldflags", "-X github.com/sagernet/sing-box/constant.Version="+currentTag)
 
 	sharedTags = append(sharedTags, "with_gvisor", "with_quic", "with_wireguard", "with_utls", "with_clash_api", "with_conntrack")
-	darwinTags = append(darwinTags, "with_dhcp")
+	macOSTags = append(macOSTags, "with_dhcp")
 	memcTags = append(memcTags, "with_tailscale")
 	notMemcTags = append(notMemcTags, "with_low_memory")
 	debugTags = append(debugTags, "debug")
@@ -160,7 +160,9 @@ func buildApple() {
 		"-tags-not-macos=with_low_memory",
 	}
 	if !withTailscale {
-		args = append(args, "-tags-macos="+strings.Join(memcTags, ","))
+		args = append(args, "-tags-macos="+strings.Join(append(macOSTags, memcTags...), ","))
+	} else {
+		args = append(args, "-tags-macos="+strings.Join(macOSTags, ","))
 	}
 
 	if !debugEnabled {
@@ -169,7 +171,7 @@ func buildApple() {
 		args = append(args, debugFlags...)
 	}
 
-	tags := append(sharedTags, darwinTags...)
+	tags := sharedTags
 	if withTailscale {
 		tags = append(tags, memcTags...)
 	}

dns/transport/local/local_darwin.go

@@ -74,12 +74,14 @@ func (t *Transport) Start(stage adapter.StartStage) error {
 			break
 		}
 	}
-	if t.fallback {
-		t.dhcpTransport = newDHCPTransport(t.TransportAdapter, log.ContextWithOverrideLevel(t.ctx, log.LevelDebug), t.dialer, t.logger)
-		if t.dhcpTransport != nil {
-			err := t.dhcpTransport.Start(stage)
-			if err != nil {
-				return err
+	if !C.IsIos {
+		if t.fallback {
+			t.dhcpTransport = newDHCPTransport(t.TransportAdapter, log.ContextWithOverrideLevel(t.ctx, log.LevelDebug), t.dialer, t.logger)
+			if t.dhcpTransport != nil {
+				err := t.dhcpTransport.Start(stage)
+				if err != nil {
+					return err
+				}
 			}
 		}
 	}
@@ -104,10 +106,12 @@ func (t *Transport) Exchange(ctx context.Context, message *mDNS.Msg) (*mDNS.Msg,
 	if !t.fallback {
 		return t.exchange(ctx, message, domain)
 	}
-	if t.dhcpTransport != nil {
-		dhcpTransports, _ := t.dhcpTransport.Fetch()
-		if len(dhcpTransports) > 0 {
-			return t.dhcpTransport.Exchange0(ctx, message, dhcpTransports)
+	if !C.IsIos {
+		if t.dhcpTransport != nil {
+			dhcpTransports, _ := t.dhcpTransport.Fetch()
+			if len(dhcpTransports) > 0 {
+				return t.dhcpTransport.Exchange0(ctx, message, dhcpTransports)
+			}
 		}
 	}
 	if t.preferGo {
@@ -131,5 +135,9 @@ func (t *Transport) Exchange(ctx context.Context, message *mDNS.Msg) (*mDNS.Msg,
 		}
 		return dns.FixedResponse(message.Id, question, addresses, C.DefaultDNSTTL), nil
 	}
-	return nil, E.New("only A and AAAA queries are supported on Apple platforms when using TUN and DHCP unavailable.")
+	if C.IsIos {
+		return nil, E.New("only A and AAAA queries are supported on iOS and tvOS when using NetworkExtension.")
+	} else {
+		return nil, E.New("only A and AAAA queries are supported on macOS when using NetworkExtension and DHCP unavailable.")
+	}
 }