Wake up AWDL on Darwin if awdl0 is an enabled multicast interface

src/yggdrasil/multicast.go

@@ -50,7 +50,7 @@ func (m *multicast) start() error {
 		}
 		listenString := fmt.Sprintf("[::]:%v", addr.Port)
 		lc := net.ListenConfig{
-			Control: multicastReuse,
+			Control: m.multicastReuse,
 		}
 		conn, err := lc.ListenPacket(context.Background(), "udp6", listenString)
 		if err != nil {
@@ -61,6 +61,7 @@ func (m *multicast) start() error {
 			// Windows can't set this flag, so we need to handle it in other ways
 		}
 
+		m.multicastWake()
 		go m.listen()
 		go m.announce()
 	}

src/yggdrasil/multicast_darwin.go

@@ -2,10 +2,33 @@
 
 package yggdrasil
 
+/*
+#cgo CFLAGS: -x objective-c
+#cgo LDFLAGS: -framework Foundation
+#import <Foundation/Foundation.h>
+void WakeUpAWDL() {
+	id delegateObject; // Assume this exists.
+	NSNetServiceBrowser *serviceBrowser;
+
+	serviceBrowser = [[NSNetServiceBrowser alloc] init];
+	serviceBrowser.includesPeerToPeer = YES;
+	[serviceBrowser searchForServicesOfType:@"_yggdrasil._tcp" inDomain:@""];
+}
+*/
+import "C"
 import "syscall"
 import "golang.org/x/sys/unix"
 
-func multicastReuse(network string, address string, c syscall.RawConn) error {
+func (m *multicast) multicastWake() {
+	for _, intf := range m.interfaces() {
+		if intf.Name == "awdl0" {
+			m.core.log.Infoln("Multicast discovery is waking up AWDL")
+			C.WakeUpAWDL()
+		}
+	}
+}
+
+func (m *multicast) multicastReuse(network string, address string, c syscall.RawConn) error {
 	var control error
 	var reuseport error
 	var recvanyif error

src/yggdrasil/multicast_other.go

@@ -4,6 +4,10 @@ package yggdrasil
 
 import "syscall"
 
-func multicastReuse(network string, address string, c syscall.RawConn) error {
+func (m *multicast) multicastWake() {
+
+}
+
+func (m *multicast) multicastReuse(network string, address string, c syscall.RawConn) error {
 	return nil
 }

src/yggdrasil/multicast_unix.go

@@ -5,7 +5,11 @@ package yggdrasil
 import "syscall"
 import "golang.org/x/sys/unix"
 
-func multicastReuse(network string, address string, c syscall.RawConn) error {
+func (m *multicast) multicastWake() {
+
+}
+
+func (m *multicast) multicastReuse(network string, address string, c syscall.RawConn) error {
 	var control error
 	var reuseport error
 

src/yggdrasil/multicast_windows.go

@@ -5,7 +5,11 @@ package yggdrasil
 import "syscall"
 import "golang.org/x/sys/windows"
 
-func multicastReuse(network string, address string, c syscall.RawConn) error {
+func (m *multicast) multicastWake() {
+
+}
+
+func (m *multicast) multicastReuse(network string, address string, c syscall.RawConn) error {
 	var control error
 	var reuseaddr error